Advancing chimeric antigen receptor T cell therapy with CRISPR/Cas9.

PubMed

Ren, Jiangtao; Zhao, Yangbing

2017-09-01

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (CRISPR/Cas9) system, an RNA-guided DNA targeting technology, is triggering a revolution in the field of biology. CRISPR/Cas9 has demonstrated great potential for genetic manipulation. In this review, we discuss the current development of CRISPR/Cas9 technologies for therapeutic applications, especially chimeric antigen receptor (CAR) T cell-based adoptive immunotherapy. Different methods used to facilitate efficient CRISPR delivery and gene editing in T cells are compared. The potential of genetic manipulation using CRISPR/Cas9 system to generate universal CAR T cells and potent T cells that are resistant to exhaustion and inhibition is explored. We also address the safety concerns associated with the use of CRISPR/Cas9 gene editing and provide potential solutions and future directions of CRISPR application in the field of CAR T cell immunotherapy. As an integration-free gene insertion method, CRISPR/Cas9 holds great promise as an efficient gene knock-in platform. Given the tremendous progress that has been made in the past few years, we believe that the CRISPR/Cas9 technology holds immense promise for advancing immunotherapy.

Acyldepsipeptide antibiotics as a potential therapeutic agent against Clostridium difficile recurrent infections.

PubMed

Gil, Fernando; Paredes-Sabja, Daniel

2016-09-01

Alternative antimicrobial therapies based on acyldepsipeptides may hold promising results, based on the fact that they have shown to efficiently eradicate persister cells, stationary cells and cell in biofilm structures of several pathogenic bacteria from the infected host. Clostridium difficile infection is considered the result of extensive hospital use of expanded-spectrum antibiotics, which cause dysbiosis of the intestinal microbiota, enhancing susceptibility to infection and persistence. Considering the urgent need for the development of novel and efficient antimicrobial strategies against C. difficile, we review the potential application to treat C. difficile infections of acyldepsipeptides family of antibiotics, its mechanism of action and current developmental stages.

Development and performance characterization of an electric ground vehicle with independently actuated in-wheel motors

NASA Astrophysics Data System (ADS)

Wang, Rongrong; Chen, Yan; Feng, Daiwei; Huang, Xiaoyu; Wang, Junmin

This paper presents the development and experimental characterizations of a prototyping pure electric ground vehicle, which is equipped with four independently actuated in-wheel motors (FIAIWM) and is powered by a 72 V 200 Ah LiFeYPO 4 battery pack. Such an electric ground vehicle (EGV) employs four in-wheel (or hub) motors to independently drive/brake the four wheels and is one of the promising vehicle architectures primarily due to its actuation flexibility, energy efficiency, and performance potentials. Experimental data obtained from the EGV chassis dynamometer tests were employed to generate the in-wheel motor torque response and power efficiency maps in both driving and regenerative braking modes. A torque distribution method is proposed to show the potentials of optimizing the FIAIWM EGV operational energy efficiency by utilizing the actuation flexibility and the characterized in-wheel motor efficiency and torque response.

Ab-initio investigations for opto-electronic response of (Cd, Zn)Ga2Te4: Promising solar PV materials

NASA Astrophysics Data System (ADS)

Sahariya, Jagrati; Soni, Amit; Kumar, Pancham

2018-04-01

In this paper, the first principle calculations are performed to analyze the structural, electronic and optical behavior of promising solar materials (Cd,Zn)Ga2Te4. To perform these calculations we have used one of the most accurate Full Potential Linearized Augmented Plane Wave (FP-LAPW) method. The ground state properties of these compounds are confirmed over here after proper examination of energy and charge convergence using Perdew-Burke-Ernzerhof (PBE-sol) exchange correlation potential. The investigations performed such as energy band structure, Density of States (DOS), optical parameters like complex dielectric function and absorption co-efficient are discussed over here to understand the overall response of the chosen system.

Gastric-sparing nitric oxide-releasable 'true' prodrugs of aspirin and naproxen.

PubMed

Gund, Machhindra; Gaikwad, Parikshit; Borhade, Namdev; Burhan, Aslam; Desai, Dattatraya C; Sharma, Ankur; Dhiman, Mini; Patil, Mohan; Sheikh, Javed; Thakre, Gajanan; Tipparam, Santhosh G; Sharma, Somesh; Nemmani, Kumar V S; Satyam, Apparao

2014-12-15

Nitric oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) are gaining attention as potentially gastric-sparing NSAIDs. Herein, we report a novel class of '1-(nitrooxy)ethyl ester' group-containing NSAIDS as efficient NO releasing 'true' prodrugs of aspirin and naproxen. While an aspirin prodrug exhibited comparable oral bioavailability and antiplatelet activity (i.e., TXB2 inhibition) to those of aspirin, a naproxen prodrug exhibited better bioavailability than naproxen. These promising NO-NSAIDs protected experimental rats from gastric damage. We therefore believe that these promising NO-NSAIDs could represent a new class of potentially 'Safe NSAIDs' for the treatment of arthritic pain, inflammation and cardiovascular disorders in the case of NO-aspirin. Copyright © 2014 Elsevier Ltd. All rights reserved.

Progress on coal-derived fuels for aviation systems

NASA Technical Reports Server (NTRS)

Witcofski, R. D.

1978-01-01

The results of engineering studies of coal-derived aviation fuels and their potential application to the air transportation system are presented. Synthetic aviation kerosene (SYN. JET-A), liquid methane (LCH4) and liquid hydrogen (LH2) appear to be the most promising coal-derived fuels. Aircraft configurations fueled with LH2, their fuel systems, and their ground requirements at the airport are identified. Energy efficiency, transportation hazards, and costs are among the factors considered. It is indicated that LCH4 is the most energy efficient to produce, and provides the most efficient utilization of coal resources and the least expensive ticket as well.

Photodetectors for scintillator proportionality measurement

NASA Astrophysics Data System (ADS)

Moses, William W.; Choong, Woon-Seng; Hull, Giulia; Payne, Steve; Cherepy, Nerine; Valentine, John D.

2009-10-01

We evaluate photodetectors for use in a Compton Coincidence apparatus designed for measuring scintillator proportionality. There are many requirements placed on the photodetector in these systems, including active area, linearity, and the ability to accurately measure low light levels (which implies high quantum efficiency and high signal-to-noise ratio). Through a combination of measurement and Monte Carlo simulation, we evaluate a number of potential photodetectors, especially photomultiplier tubes and hybrid photodetectors. Of these, we find that the most promising devices available are photomultiplier tubes with high (˜50%) quantum efficiency, although hybrid photodetectors with high quantum efficiency would be preferable.

Maximal power output by solar cells with angular confinement.

PubMed

Höhn, Oliver; Kraus, Tobias; Bauhuis, Gerard; Schwarz, Ulrich T; Bläsi, Benedikt

2014-05-05

Angularly selective filters can increase the efficiency of radiatively limited solar cells. A restriction of the acceptance angle is linked to the kind of utilizable solar spectrum (global or direct radiation). This has to be considered when calculating the potential enhancement of both the efficiency and the power output. In this paper, different concepts to realize angularly selective filters are compared regarding their limits for efficiency and power output per unit area. First experimental results of a promising system based on a thin-film filter as the angularly selective element are given to demonstrate the practical relevance of such systems.

Developing Discontinuous Galerkin Methods for Solving Multiphysics Problems in General Relativity

NASA Astrophysics Data System (ADS)

Kidder, Lawrence; Field, Scott; Teukolsky, Saul; Foucart, Francois; SXS Collaboration

2016-03-01

Multi-messenger observations of the merger of black hole-neutron star and neutron star-neutron star binaries, and of supernova explosions will probe fundamental physics inaccessible to terrestrial experiments. Modeling these systems requires a relativistic treatment of hydrodynamics, including magnetic fields, as well as neutrino transport and nuclear reactions. The accuracy, efficiency, and robustness of current codes that treat all of these problems is not sufficient to keep up with the observational needs. We are building a new numerical code that uses the Discontinuous Galerkin method with a task-based parallelization strategy, a promising combination that will allow multiphysics applications to be treated both accurately and efficiently on petascale and exascale machines. The code will scale to more than 100,000 cores for efficient exploration of the parameter space of potential sources and allowed physics, and the high-fidelity predictions needed to realize the promise of multi-messenger astronomy. I will discuss the current status of the development of this new code.

A low-cost iron-cadmium redox flow battery for large-scale energy storage

NASA Astrophysics Data System (ADS)

Zeng, Y. K.; Zhao, T. S.; Zhou, X. L.; Wei, L.; Jiang, H. R.

2016-10-01

The redox flow battery (RFB) is one of the most promising large-scale energy storage technologies that offer a potential solution to the intermittency of renewable sources such as wind and solar. The prerequisite for widespread utilization of RFBs is low capital cost. In this work, an iron-cadmium redox flow battery (Fe/Cd RFB) with a premixed iron and cadmium solution is developed and tested. It is demonstrated that the coulombic efficiency and energy efficiency of the Fe/Cd RFB reach 98.7% and 80.2% at 120 mA cm-2, respectively. The Fe/Cd RFB exhibits stable efficiencies with capacity retention of 99.87% per cycle during the cycle test. Moreover, the Fe/Cd RFB is estimated to have a low capital cost of 108 kWh-1 for 8-h energy storage. Intrinsically low-cost active materials, high cell performance and excellent capacity retention equip the Fe/Cd RFB to be a promising solution for large-scale energy storage systems.

A highly efficient silole-containing dithienylethene with excellent thermal stability and fatigue resistance: a promising candidate for optical memory storage materials.

PubMed

Chan, Jacky Chi-Hung; Lam, Wai Han; Yam, Vivian Wing-Wah

2014-12-10

Diarylethene compounds are potential candidates for applications in optical memory storage systems and photoswitchable molecular devices; however, they usually show low photocycloreversion quantum yields, which result in ineffective erasure processes. Here, we present the first highly efficient photochromic silole-containing dithienylethene with excellent thermal stability and fatigue resistance. The photochemical quantum yields for photocyclization and photocycloreversion of the compound are found to be high and comparable to each other; the latter of which is rarely found in diarylethene compounds. These would give rise to highly efficient photoswitchable material with effective writing and erasure processes. Incorporation of the silole moiety as a photochromic dithienylethene backbone also was demonstrated to enhance the thermal stability of the closed form, in which the thermal backward reaction to the open form was found to be negligible even at 100 °C, which leads to a promising candidate for use as photoswitchable materials and optical memory storage.

“Wine-Dark Sea” in an Organic Flow Battery: Storing Negative Charge in 2,1,3-Benzothiadiazole Radicals Leads to Improved Cyclability

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

Duan, Wentao; Huang, Jinhua; Kowalski, Jeffrey A.

Redox-active organic materials (ROMs) have shown great promise for redox flow battery applications but generally encounter limited cycling efficiency and stability at relevant redox material concentrations in nonaqueous systems. Here we report a new heterocyclic organic anolyte molecule, 2,1,3-benzothiadiazole, that has high solubility, a low redox potential, and fast electrochemical kinetics. Coupling it with a benchmark catholyte ROM, the nonaqueous organic flow battery demonstrated significant improvement in cyclable redox material concentrations and cell efficiencies compared to the state-of-the-art nonaqueous systems. Especially, this system produced exceeding cyclability with relatively stable efficiencies and capacities at high ROM concentrations (>0.5 M), which ismore » ascribed to the highly delocalized charge densities in the radical anions of 2,1,3-benzothiadiazole, leading to good chemical stability. As a result, this material development represents significant progress toward promising next-generation energy storage.« less

A Review of Microbubble and its Applications in Ozonation

NASA Astrophysics Data System (ADS)

Shangguan, Yufei; Yu, Shuili; Gong, Chao; Wang, Yue; Yang, Wangzhen; Hou, Li-an

2018-03-01

Ozonation has been demonstrated to be an effective technology for the oxidation of organic matters in water treatment. But the low solubility and low mass transfer efficiency limit the application. Microbubble technology has the potential of enhancing gas-liquid mass transfer efficiency, thus it can be applied in ozonation process. The applications of microbubble ozonation have shown advantages over macro bubble ozonation in mass transfer and reaction rate. Microbubble ozonation will be a promising treatment both in water and wastewater treatment.

Moisture removal characteristics of thin layer rough rice under sequenced infrared radiation heating and cooling

USDA-ARS?s Scientific Manuscript database

Rice drying with infrared (IR) radiation has been investigated during recent years and showed promising potential with improved quality and energy efficiency. The objective of this study was to further investigate the moisture removal characteristics of thin layer rough rice heated by IR and cooled ...

Energy efficiency in the U.S. residential sector: An engineering and economic assessment of opportunities for large energy savings and greenhouse gas emissions reductions

NASA Astrophysics Data System (ADS)

Lima de Azevedo, Ines Margarida

Energy efficiency and conservation is a very promising part of a portfolio of the needed strategies to mitigate climate change. Several technologies and energy efficiency measures in the residential sector offer potential for large energy savings. However, while energy efficiency options are currently considered as a means of reducing carbon emissions, there is still large uncertainty about the effect of such measures on overall carbon savings. The first part of this thesis provides a national assessment of the energy efficiency potential in the residential sector under several different scenarios, which include the perspectives of different economic agents (consumers, utilities, ESCOs, and a society). The scenarios also include maximizing energy, electricity or carbon dioxide savings. The second part of this thesis deals with a detailed assessment of the potential for white-light LEDs for energy and carbon dioxide savings in the U.S. commercial and residential sectors. Solid-state lighting shows great promise as a source of efficient, affordable, color-balanced white light. Indeed, assuming market discount rates, the present work demonstrates that white solid-state lighting already has a lower levelized annual cost (LAC) than incandescent bulbs and that it will be lower than that of the most efficient fluorescent bulbs by the end of this decade. However, a large literature indicates that households do not make their decisions in terms of simple expected economic value. The present analysis shows that incorporating the findings from literature on high implicit discount rates from households when performing decisions towards efficient technologies delays the adoption of white LEDs by a couple of years. After a review of the technology, the present work compares the electricity consumption, carbon emissions and cost-effectiveness of current lighting technologies, when accounting for expected performance evolution through 2015. Simulations of lighting electricity consumption and implicit greenhouse gases emissions for the U.S. residential and commercial sectors through 2015 under different policy scenarios (voluntary solid-state lighting adoption, implementation of lighting standards in new construction and rebate programs or equivalent subsidies) are also included.

Carbon nanotube-mediated siRNA delivery for gene silencing in cancer cells

NASA Astrophysics Data System (ADS)

Hong, Tu; Guo, Honglian; Xu, Yaqiong

2011-10-01

Small interfering RNA (siRNA) is potentially a promising tool in influencing gene expression with a high degree of target specificity. However, its poor intracellular uptake, instability in vivo, and non-specific immune stimulations impeded its effect in clinical applications. In this study, carbon nanotubes (CNTs) functionalized with two types of phospholipid-polyethylene glycol (PEG) have shown capabilities to stabilize siRNA in cell culture medium during the transfection and efficiently deliver siRNA into neuroblastoma and breast cancer cells. Moreover, the intrinsic optical properties of CNTs have been investigated through absorption and fluorescence measurements. We have found that the directly-functionalized groups play an important role on the fluorescence imaging of functionalized CNTs. The unique fluorescence imaging and high delivery efficiency make CNTs a promising material to deliver drugs and evaluate the treatment effect simultaneously.

DU Processing Efficiency and Reclamation: Plasma Arc Melting

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

Imhoff, Seth D.; Aikin, Jr., Robert M.; Swenson, Hunter

The work described here corresponds to one piece of a larger effort to increase material usage efficiency during DU processing operations. In order to achieve this goal, multiple technologies and approaches are being tested. These technologies occupy a spectrum of technology readiness levels (TRLs). Plasma arc melting (PAM) is one of the technologies being investigated. PAM utilizes a high temperature plasma to melt materials. Depending on process conditions, there are potential opportunities for recycling and material reclamation. When last routinely operational, the LANL research PAM showed extremely promising results for recycling and reclamation of DU and DU alloys. The currentmore » TRL is lower due to machine idleness for nearly two decades, which has proved difficult to restart. This report describes the existing results, promising techniques, and the process of bringing this technology back to readiness at LANL.« less

Accelerated molecular dynamics: A promising and efficient simulation method for biomolecules

NASA Astrophysics Data System (ADS)

Hamelberg, Donald; Mongan, John; McCammon, J. Andrew

2004-06-01

Many interesting dynamic properties of biological molecules cannot be simulated directly using molecular dynamics because of nanosecond time scale limitations. These systems are trapped in potential energy minima with high free energy barriers for large numbers of computational steps. The dynamic evolution of many molecular systems occurs through a series of rare events as the system moves from one potential energy basin to another. Therefore, we have proposed a robust bias potential function that can be used in an efficient accelerated molecular dynamics approach to simulate the transition of high energy barriers without any advance knowledge of the location of either the potential energy wells or saddle points. In this method, the potential energy landscape is altered by adding a bias potential to the true potential such that the escape rates from potential wells are enhanced, which accelerates and extends the time scale in molecular dynamics simulations. Our definition of the bias potential echoes the underlying shape of the potential energy landscape on the modified surface, thus allowing for the potential energy minima to be well defined, and hence properly sampled during the simulation. We have shown that our approach, which can be extended to biomolecules, samples the conformational space more efficiently than normal molecular dynamics simulations, and converges to the correct canonical distribution.

An Overview of Metallic Nanowire Networks, Promising Building Blocks for Next Generation Transparent Conductors: Emergence, Fundamentals and Challenges

NASA Astrophysics Data System (ADS)

Pirsalami, Sedigheh; Zebarjad, Seyed Mojtaba; Daneshmanesh, Habib

2017-08-01

Transparent conductors (TCs) have a wide range of applications in numerous electronic and optoelectronic devices. This review provides an overview of the emergence of metallic nanowire networks (MNNs) as promising building blocks for the next generation transparent conductors. The fundamental aspects, structure-property relations, fabrication techniques and the corresponding challenges are reviewed. Theoretical and experimental researches suggest that nanowires with smaller diameter, longer length and higher aspect ratio have higher performance. Yet, the development of an efficient synthesis technique for the production of MNNs has remained a challenge. The synthesis method is also crucial to the scalability and the commercial potential of these emerging TCs. The most promising techniques for the synthesis together with their advantages, limitations and the recent findings are here discussed. Finally, we will try to show the promising future research trends in MNNs to have an approach to design the next generation TCs.

The Potential Role of Natural Gas Power Plants with Carbon Capture and Storage as a Bridge to a Low-Carbon Future

EPA Science Inventory

Natural gas combined-cycle (NGCC) turbines with carbon capture and storage (CCS) are a promising technology for reducing carbon dioxide (CO2) emissions in the electric sector. However, the high cost and efficiency penalties associated with CCS, as well as methane leakage from nat...

Biocatalytic Synthesis of the Rare Sugar Kojibiose: Process Scale-Up and Application Testing.

PubMed

Beerens, Koen; De Winter, Karel; Van de Walle, Davy; Grootaert, Charlotte; Kamiloglu, Senem; Miclotte, Lisa; Van de Wiele, Tom; Van Camp, John; Dewettinck, Koen; Desmet, Tom

2017-07-26

Cost-efficient (bio)chemical production processes are essential to evaluate the commercial and industrial applications of promising carbohydrates and also are essential to ensure economically viable production processes. Here, the synthesis of the naturally occurring disaccharide kojibiose (2-O-α-d-glucopyranosyl-d-glucopyranoside) was evaluated using different Bifidobacterium adolescentis sucrose phosphorylase variants. Variant L341I_Q345S was found to efficiently synthesize kojibiose while remaining fully active after 1 week of incubation at 55 °C. Process optimization allowed kojibiose production at the kilogram scale, and simple but efficient downstream processing, using a yeast treatment and crystallization, resulted in more than 3 kg of highly pure crystalline kojibiose (99.8%). These amounts allowed a deeper characterization of its potential in food applications. It was found to have possible beneficial health effects, including delayed glucose release and potential to trigger SCFA production. Finally, we compared the bulk functionality of highly pure kojibiose to that of sucrose, hereby mapping its potential as a new sweetener in confectionery products.

Development and manufacture of reactive-transfer-printed CIGS photovoltaic modules

NASA Astrophysics Data System (ADS)

Eldada, Louay; Sang, Baosheng; Lu, Dingyuan; Stanbery, Billy J.

2010-09-01

In recent years, thin-film photovoltaic (PV) companies started realizing their low manufacturing cost potential, and grabbing an increasingly larger market share from multicrystalline silicon companies. Copper Indium Gallium Selenide (CIGS) is the most promising thin-film PV material, having demonstrated the highest energy conversion efficiency in both cells and modules. However, most CIGS manufacturers still face the challenge of delivering a reliable and rapid manufacturing process that can scale effectively and deliver on the promise of this material system. HelioVolt has developed a reactive transfer process for CIGS absorber formation that has the benefits of good compositional control, high-quality CIGS grains, and a fast reaction. The reactive transfer process is a two stage CIGS fabrication method. Precursor films are deposited onto substrates and reusable print plates in the first stage, while in the second stage, the CIGS layer is formed by rapid heating with Se confinement. High quality CIGS films with large grains were produced on a full-scale manufacturing line, and resulted in high-efficiency large-form-factor modules. With 14% cell efficiency and 12% module efficiency, HelioVolt started to commercialize the process on its first production line with 20 MW nameplate capacity.

Cascaded second-order processes for the efficient generation of narrowband terahertz radiation

NASA Astrophysics Data System (ADS)

Cirmi, Giovanni; Hemmer, Michael; Ravi, Koustuban; Reichert, Fabian; Zapata, Luis E.; Calendron, Anne-Laure; Çankaya, Hüseyin; Ahr, Frederike; Mücke, Oliver D.; Matlis, Nicholas H.; Kärtner, Franz X.

2017-02-01

The generation of high-energy narrowband terahertz radiation has gained heightened importance in recent years due to its potentially transformative impact on spectroscopy, high-resolution radar and more recently electron acceleration. Among various applications, such terahertz radiation is particularly important for table-top free electron lasers, which are at the moment a subject of extensive research. Second-order nonlinear optical methods are among the most promising techniques to achieve the required coherent radiation with energy > 10 mJ, peak field > 100 MV m-1, and frequency between 0.1 and 1 THz. However, they are conventionally thought to suffer from low efficiencies < ˜10-3, due to the high ratio between optical and terahertz photon energies, in what is known as the Manley-Rowe limitation. In this paper, we review the current second-order nonlinear optical methods for the generation of narrowband terahertz radiation. We explain how to employ spectral cascading to increase the efficiency beyond the Manley-Rowe limit and describe the first experimental results in the direction of a terahertz-cascaded optical parametric amplifier, a novel technique which promises to fully exploit spectral cascading to generate narrowband terahertz radiation with few percent optical-to-terahertz conversion efficiency.

GaN-Based Laser Wireless Power Transfer System.

PubMed

De Santi, Carlo; Meneghini, Matteo; Caria, Alessandro; Dogmus, Ezgi; Zegaoui, Malek; Medjdoub, Farid; Kalinic, Boris; Cesca, Tiziana; Meneghesso, Gaudenzio; Zanoni, Enrico

2018-01-17

The aim of this work is to present a potential application of gallium nitride-based optoelectronic devices. By using a laser diode and a photodetector, we designed and demonstrated a free-space compact and lightweight wireless power transfer system, whose efficiency is limited by the efficiency of the receiver. We analyzed the effect of the electrical load, temperature, partial absorption and optical excitation distribution on the efficiency, by identifying heating and band-filling as the most impactful processes. By comparing the final demonstrator with a commercial RF-based Qi system, we conclude that the efficiency is still low at close range, but is promising in medium to long range applications. Efficiency may not be a limiting factor, since this concept can enable entirely new possibilities and designs, especially relevant for space applications.

GaN-Based Laser Wireless Power Transfer System

PubMed Central

Meneghini, Matteo; Caria, Alessandro; Dogmus, Ezgi; Zegaoui, Malek; Medjdoub, Farid; Kalinic, Boris; Meneghesso, Gaudenzio; Zanoni, Enrico

2018-01-01

The aim of this work is to present a potential application of gallium nitride-based optoelectronic devices. By using a laser diode and a photodetector, we designed and demonstrated a free-space compact and lightweight wireless power transfer system, whose efficiency is limited by the efficiency of the receiver. We analyzed the effect of the electrical load, temperature, partial absorption and optical excitation distribution on the efficiency, by identifying heating and band-filling as the most impactful processes. By comparing the final demonstrator with a commercial RF-based Qi system, we conclude that the efficiency is still low at close range, but is promising in medium to long range applications. Efficiency may not be a limiting factor, since this concept can enable entirely new possibilities and designs, especially relevant for space applications. PMID:29342114

Megawatt-class free-electron laser concept for shipboard self-defense

NASA Astrophysics Data System (ADS)

Todd, Alan M. M.; Colson, William B.; Neil, George R.

1997-05-01

An efficient MW-class free electron laser (FEL) directed energy weapon (DEW) system holds promise for satisfying shipboard self-defense (SSD) requirements on future generations of Navy vessels because of the potential for high- power operation and the accessibility to all IR wavelengths. In order to meet shipboard packaging and prime power constraints, the power efficiency and high real-estate gradient achievable in a FEL driven by a superconducting rf accelerator is attractive. Configuration options and the key development issues for such a system are described.

Professional Advanced Research and Analysis

NASA Technical Reports Server (NTRS)

Coulman, George A.

1996-01-01

Reported here is a summary of studies examining some problems in an energy conversion system. Regenerative fuel cell systems have been suggested for future manned space missions, but to meet the needed specific power requirements substantial improvements in the state-of-the-art technologies are needed. Similar improvements are needed, with emphasis on cost reduction in addition to higher conversion efficiency, for fuel cell systems that have potential for terrestrial applications. Polymer Electrolyte Membrane (PEM) fuel cells have been identified as promising candidates for development that would lead to the desired cost reduction and increased efficiency.

Fluorescent carbon nanoparticles derived from natural materials of mango fruit for bio-imaging probes

NASA Astrophysics Data System (ADS)

Jeong, Chan Jin; Roy, Arup Kumer; Kim, Sung Han; Lee, Jung-Eun; Jeong, Ji Hoon; Insik; Park, Sung Young

2014-11-01

Water soluble fluorescent carbon nanoparticles (FCP) obtained from a single natural source, mango fruit, were developed as unique materials for non-toxic bio-imaging with different colors and particle sizes. The prepared FCPs showed blue (FCP-B), green (FCP-G) and yellow (FCP-Y) fluorescence, derived by the controlled carbonization method. The FCPs demonstrated hydrodynamic diameters of 5-15 nm, holding great promise for clinical applications. The biocompatible FCPs demonstrated great potential in biological fields through the results of in vitro imaging and in vivo biodistribution. Using intravenously administered FCPs with different colored particles, we precisely defined the clearance and biodistribution, showing rapid and efficient urinary excretion for safe elimination from the body. These findings therefore suggest the promising possibility of using natural sources for producing fluorescent materials.Water soluble fluorescent carbon nanoparticles (FCP) obtained from a single natural source, mango fruit, were developed as unique materials for non-toxic bio-imaging with different colors and particle sizes. The prepared FCPs showed blue (FCP-B), green (FCP-G) and yellow (FCP-Y) fluorescence, derived by the controlled carbonization method. The FCPs demonstrated hydrodynamic diameters of 5-15 nm, holding great promise for clinical applications. The biocompatible FCPs demonstrated great potential in biological fields through the results of in vitro imaging and in vivo biodistribution. Using intravenously administered FCPs with different colored particles, we precisely defined the clearance and biodistribution, showing rapid and efficient urinary excretion for safe elimination from the body. These findings therefore suggest the promising possibility of using natural sources for producing fluorescent materials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04805a

Helper-Dependent Adenoviral Vectors.

PubMed

Rosewell, Amanda; Vetrini, Francesco; Ng, Philip

2011-10-29

Helper-dependent adenoviral vectors are devoid of all viral coding sequences, possess a large cloning capacity, and can efficiently transduce a wide variety of cell types from various species independent of the cell cycle to mediate long-term transgene expression without chronic toxicity. These non-integrating vectors hold tremendous potential for a variety of gene transfer and gene therapy applications. Here, we review the production technologies, applications, obstacles to clinical translation and their potential resolutions, and the future challenges and unanswered questions regarding this promising gene transfer technology.

Helper-Dependent Adenoviral Vectors

PubMed Central

Rosewell, Amanda; Vetrini, Francesco; Ng, Philip

2012-01-01

Helper-dependent adenoviral vectors are devoid of all viral coding sequences, possess a large cloning capacity, and can efficiently transduce a wide variety of cell types from various species independent of the cell cycle to mediate long-term transgene expression without chronic toxicity. These non-integrating vectors hold tremendous potential for a variety of gene transfer and gene therapy applications. Here, we review the production technologies, applications, obstacles to clinical translation and their potential resolutions, and the future challenges and unanswered questions regarding this promising gene transfer technology. PMID:24533227

A robust gene-stacking method utilizing yeast assembly for plant synthetic biology

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

Shih, Patrick M.; Vuu, Khanh; Mansoori, Nasim

The advent and growth of synthetic biology has demonstrated its potential as a promising avenue of research to address many societal needs. But, plant synthetic biology efforts have been hampered by a dearth of DNA part libraries, versatile transformation vectors and efficient assembly strategies. We describe a versatile system (named jStack) utilizing yeast homologous recombination to efficiently assemble DNA into plant transformation vectors. We also demonstrate how this method can facilitate pathway engineering of molecules of pharmaceutical interest, production of potential biofuels and shuffling of disease-resistance traits between crop species. Our approach provides a powerful alternative to conventional strategies formore » stacking genes and traits to address many impending environmental and agricultural challenges.« less

A robust gene-stacking method utilizing yeast assembly for plant synthetic biology

DOE PAGES

Shih, Patrick M.; Vuu, Khanh; Mansoori, Nasim; ...

2016-10-26

The advent and growth of synthetic biology has demonstrated its potential as a promising avenue of research to address many societal needs. But, plant synthetic biology efforts have been hampered by a dearth of DNA part libraries, versatile transformation vectors and efficient assembly strategies. We describe a versatile system (named jStack) utilizing yeast homologous recombination to efficiently assemble DNA into plant transformation vectors. We also demonstrate how this method can facilitate pathway engineering of molecules of pharmaceutical interest, production of potential biofuels and shuffling of disease-resistance traits between crop species. Our approach provides a powerful alternative to conventional strategies formore » stacking genes and traits to address many impending environmental and agricultural challenges.« less

Thermionic/AMTEC cascade converter concept for high-efficiency space power

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

Hagan, T.H. van; Smith, J.N. Jr.; Schuller, M.

1996-12-31

This paper presents trade studies that address the use of the thermionic/AMTEC cell--a cascaded, high-efficiency, static power conversion concept that appears well-suited to space power applications. Both the thermionic and AMTEC power conversion approaches have been shown to be promising candidates for space power. Thermionics offers system compactness via modest efficiency at high heat rejection temperatures, and AMTEC offers high efficiency at modest heat rejection temperature. From a thermal viewpoint the two are ideally suited for cascaded power conversion: thermionic heat rejection and AMTEC heat source temperatures are essentially the same. In addition to realizing conversion efficiencies potentially as highmore » as 35--40%, such a cascade offers the following perceived benefits: survivability; simplicity; technology readiness; and technology growth. Mechanical approaches and thermal/electric matching criteria for integrating thermionics and AMTEC into a single conversion device are described. Focusing primarily on solar thermal space power applications, parametric trends are presented to show the performance and cost potential that should be achievable with present-day technology in cascaded thermionic/AMTEC systems.« less

Induced Pluripotent Stem Cells: Generation, Characterization, and Differentiation--Methods and Protocols.

PubMed

Graversen, Veronica Kon; Chavala, Sai H

2016-01-01

Reprogramming fibroblasts into induced pluripotent stem cells (iPSC) remains a promising technique for cell replacement therapy. Diverse populations of somatic cells have been examined for their reprogramming potential. Recently, ocular ciliary body epithelial cells (CECs) have been reprogrammed with high reprogramming efficiency and single transcription factor reprogramming, making them an exciting candidate for cellular reprogramming strategies.

Selection of transformation-efficient barley genotypes based on TFA (transformation amenability) haplotype and higher resolution mapping of the TFA loci.

PubMed

Hisano, Hiroshi; Meints, Brigid; Moscou, Matthew J; Cistue, Luis; Echávarri, Begoña; Sato, Kazuhiro; Hayes, Patrick M

2017-04-01

The genetic substitution of transformation amenability alleles from 'Golden Promise' can facilitate the development of transformation-efficient lines from recalcitrant barley cultivars. Barley (Hordeum vulgare) cv. 'Golden Promise' is one of the most useful and well-studied cultivars for genetic manipulation. In a previous report, we identified several transformation amenability (TFA) loci responsible for Agrobacterium-mediated transformation using the F 2 generation of immature embryos, derived from 'Haruna Nijo' × 'Golden Promise,' as explants. In this report, we describe higher density mapping of these TFA regions with additional SNP markers using the same transgenic plants. To demonstrate the robustness of transformability alleles at the TFA loci, we genotyped 202 doubled haploid progeny from the cross 'Golden Promise' × 'Full Pint.' Based on SNP genotype, we selected lines having 'Golden Promise' alleles at TFA loci and used them for transformation. Of the successfully transformed lines, DH120366 came the closest to achieving a level of transformation efficiency comparable to 'Golden Promise.' The results validate that the genetic substitution of TFA alleles from 'Golden Promise' can facilitate the development of transformation-efficient lines from recalcitrant barley cultivars.

Finite Element Analysis in Concurrent Processing: Computational Issues

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, Jaroslaw; Watson, Brian; Vanderplaats, Garrett

2004-01-01

The purpose of this research is to investigate the potential application of new methods for solving large-scale static structural problems on concurrent computers. It is well known that traditional single-processor computational speed will be limited by inherent physical limits. The only path to achieve higher computational speeds lies through concurrent processing. Traditional factorization solution methods for sparse matrices are ill suited for concurrent processing because the null entries get filled, leading to high communication and memory requirements. The research reported herein investigates alternatives to factorization that promise a greater potential to achieve high concurrent computing efficiency. Two methods, and their variants, based on direct energy minimization are studied: a) minimization of the strain energy using the displacement method formulation; b) constrained minimization of the complementary strain energy using the force method formulation. Initial results indicated that in the context of the direct energy minimization the displacement formulation experienced convergence and accuracy difficulties while the force formulation showed promising potential.

Effect of Aggregation on Squaraine Fullerene Bulk-Heterojunction Organic Photovoltaic Devices

NASA Astrophysics Data System (ADS)

Jalan, Ishita

Organic photovoltaics (OPV) offer great promise as a low-cost renewable energy source, the relative low efficiency still challenges its commercialization potential. Small conjugated molecules like Squaraine (SQ) molecules show promising advancement in organic photovoltaics (OPV). Advantages of SQ over other materials is that it has a high extinction coefficient (>105), decent photo-stability, good synthetic reproducibility, and tunable molecular structure. With small chemical modifications, the squaraines can have substantial impact on photophysical properties and aggregation pattern, and thus on operational OPV efficiency. The squaraine molecule that will be studied in this work is a symmetric aniline-based squaraine with n-hexyl chain on the molecular arm with di hydroxyl substituents on the aniline, this will be referred to DHSQ(OH) 2. In this work, the assignment of the monomer and aggregate peak is discussed. It is known that crystallinity is important for efficient charge transport and exciton diffusion in the BHJ, this thesis focuses on thermal and solvent vapor annealing the as-cast films to reduce the amorphous regions. It is observed that crystallinity is improved but often at the expense of larger crystal size. Therefore, to achieve optimal OPV efficiency, this tradeoff is controlled to improve the crystallinity while maintaining a small, highly mixed BHJ morphology.

Phycocyanin: A Potential Drug for Cancer Treatment

PubMed Central

Jiang, Liangqian; Wang, Yujuan; Yin, Qifeng; Liu, Guoxiang; Liu, Huihui; Huang, Yajing; Li, Bing

2017-01-01

Phycocyanin isolated from marine organisms has the characteristics of high efficiency and low toxicity, and it can be used as a functional food. It has been reported that phycocyanin has anti-oxidative function, anti-inflammatory activity, anti-cancer function, immune enhancement function, liver and kidney protection pharmacological effects. Thus, phycocyanin has an important development and utilization as a potential drug, and phycocyanin has become a new hot spot in the field of drug research. So far, there are more and more studies have shown that phycocyanin has the anti-cancer effect, which can block the proliferation of cancer cells and kill cancer cells. Phycocyanin exerts anti-cancer activity by blocking tumor cell cell cycle, inducing tumor cell apoptosis and autophagy, thereby phycocyanin can serve as a promising anti-cancer agent. This review discusses the therapeutic use of phycocyanin and focuses on the latest advances of phycocyanin as a promising anti-cancer drug. PMID:29151925

Cu2O/CuO Bilayered Composite as a High-Efficiency Photocathode for Photoelectrochemical Hydrogen Evolution Reaction

NASA Astrophysics Data System (ADS)

Yang, Yang; Xu, Di; Wu, Qingyong; Diao, Peng

2016-10-01

Solar powered hydrogen evolution reaction (HER) is one of the key reactions in solar-to-chemical energy conversion. It is desirable to develop photocathodic materials that exhibit high activity toward photoelectrochemical (PEC) HER at more positive potentials because a higher potential means a lower overpotential for HER. In this work, the Cu2O/CuO bilayered composites were prepared by a facile method that involved an electrodeposition and a subsequent thermal oxidation. The resulting Cu2O/CuO bilayered composites exhibited a surprisingly high activity and good stability toward PEC HER, expecially at high potentials in alkaline solution. The photocurrent density for HER was 3.15 mA·cm-2 at the potential of 0.40 V vs. RHE, which was one of the two highest reported at the same potential on copper-oxide-based photocathode. The high photoactivity of the bilayered composite was ascribed to the following three advantages of the Cu2O/CuO heterojunction: (1) the broadened light absorption band that made more efficient use of solar energy, (2) the large space-charge-region potential that enabled a high efficiency for electron-hole separation, and (3) the high majority carrier density that ensured a faster charge transportation rate. This work reveals the potential of the Cu2O/CuO bilayered composite as a promising photocathodic material for solar water splitting.

Direct identification of metallic and semiconducting single-walled carbon nanotubes in scanning electron microscopy.

PubMed

Li, Jie; He, Yujun; Han, Yimo; Liu, Kai; Wang, Jiaping; Li, Qunqing; Fan, Shoushan; Jiang, Kaili

2012-08-08

Because of their excellent electrical and optical properties, carbon nanotubes have been regarded as extremely promising candidates for high-performance electronic and optoelectronic applications. However, effective and efficient distinction and separation of metallic and semiconducting single-walled carbon nanotubes are always challenges for their practical applications. Here we show that metallic and semiconducting single-walled carbon nanotubes on SiO(2) can have obviously different contrast in scanning electron microscopy due to their conductivity difference and thus can be effectively and efficiently identified. The correlation between conductivity and contrast difference has been confirmed by using voltage-contrast scanning electron microcopy, peak force tunneling atom force microscopy, and field effect transistor testing. This phenomenon can be understood via a proposed mechanism involving the e-beam-induced surface potential of insulators and the conductivity difference between metallic and semiconducting SWCNTs. This method demonstrates great promise to achieve rapid and large-scale distinguishing between metallic and semiconducting single-walled carbon nanotubes, adding a new function to conventional SEM.

Thermo-economic analysis of a trigeneration HCPVT power plant

NASA Astrophysics Data System (ADS)

Selviaridis, Angelos; Burg, Brian R.; Wallerand, Anna Sophia; Maréchal, François; Michel, Bruno

2015-09-01

The increasing need for electricity and heat in a growing global economy must be combined with CO2 emissions reduction, in order to limit the human influence on the environment. This calls for energy-efficient and cost-competitive renewable energy systems that are able to satisfy both pressing needs. A High-Concentration Photovoltaic Thermal (HCPVT) system is a cogeneration concept that shows promising potential in delivering electricity and heat in an efficient and cost-competitive manner. This study investigates the transient behavior of the HCPVT system and presents a thermo-economic analysis of a MW-scale trigeneration (electricity, heating and cooling) power plant. Transient simulations show a fast dynamic response of the system which results in short heat-up intervals, maximizing heat recuperation throughout the day. Despite suboptimal coupling between demand and supply, partial heat utilization throughout the year and low COP of commercially available devices for the conversion of heat into cooling, the thermo-economic analysis shows promising economic behavior, with a levelized cost of electricity close to current retail prices.

High-performance flat-panel solar thermoelectric generators with high thermal concentration

NASA Astrophysics Data System (ADS)

Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J. Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

2011-07-01

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m-2) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity.

Optimization of a Small Scale Linear Reluctance Accelerator

NASA Astrophysics Data System (ADS)

Barrera, Thor; Beard, Robby

2011-11-01

Reluctance accelerators are extremely promising future methods of transportation. Several problems still plague these devices, most prominently low efficiency. Variables to overcoming efficiency problems are many and difficult to correlate how they affect our accelerator. The study examined several differing variables that present potential challenges in optimizing the efficiency of reluctance accelerators. These include coil and projectile design, power supplies, switching, and the elusive gradient inductance problem. Extensive research in these areas has been performed from computational and theoretical to experimental. Findings show that these parameters share significant similarity to transformer design elements, thus general findings show current optimized parameters the research suggests as a baseline for further research and design. Demonstration of these current findings will be offered at the time of presentation.

New potential solutions for the chemolysis of urinary phosphate calculi determined by an in vitro study.

PubMed

Zhang, Jinqing; Wang, Shuo; Hong, Jingfan; Liu, Chunxiao; Jiang, Yanbin

2015-04-01

To find a more efficient solution for chemolysis of urinary calculi, several organic acids were chosen to form solutions by consulting the composition of a classic solution, Suby G. The solutions together with Renacidin, another classic solution, were designed to react with the 4 phosphate components of urinary stone. The processes were real-time measured and analysed by a focused beam reflectance measurement, and the efficiency factors were investigated and discussed in detail. The results show that several organic acids, e.g. hydroxyacetic acid, lactic acid and α-ketoglutaric acid, are more efficient than citric acid in dissolving urinary phosphate calculus. The new solutions containing the organic acids are promising for improving chemolysis treatment.

Cyanographone and isocyanographone — Two asymmetrically functionalized graphene pseudohalides and their potential use in chemical sensing

NASA Astrophysics Data System (ADS)

Marsoner Steinkasserer, Lukas Eugen; Pohl, Vincent; Paulus, Beate

2018-02-01

Graphene pseudohalides are natural candidates for use in molecular sensing due to their greater chemical activity as compared to both graphene halides and pristine graphene. Though their study is still in its infancy, being hindered until recently by the unavailability of both selective and efficient procedures for their synthesis, they promise to considerably widen the application potential of chemically modified graphenes. Herein, we employ van der Waals density functional theory to study the structural and electronic properties of two selected graphene pseudohalides, namely, cyanographone and isocyanographone and investigate the potential use of the latter as a chemical sensor via electron transport calculations.

Interlayer interactions in graphites.

PubMed

Chen, Xiaobin; Tian, Fuyang; Persson, Clas; Duan, Wenhui; Chen, Nan-xian

2013-11-06

Based on ab initio calculations of both the ABC- and AB-stacked graphites, interlayer potentials (i.e., graphene-graphene interaction) are obtained as a function of the interlayer spacing using a modified Möbius inversion method, and are used to calculate basic physical properties of graphite. Excellent consistency is observed between the calculated and experimental phonon dispersions of AB-stacked graphite, showing the validity of the interlayer potentials. More importantly, layer-related properties for nonideal structures (e.g., the exfoliation energy, cleave energy, stacking fault energy, surface energy, etc.) can be easily predicted from the interlayer potentials, which promise to be extremely efficient and helpful in studying van der Waals structures.

Design of an organic redox mediator and optimization of an organic counter electrode for efficient transparent bifacial dye-sensitized solar cells.

PubMed

Li, Xiong; Ku, Zhiliang; Rong, Yaoguang; Liu, Guanghui; Liu, Linfeng; Liu, Tongfa; Hu, Min; Yang, Ying; Wang, Heng; Xu, Mi; Xiang, Peng; Han, Hongwei

2012-11-07

A new thiolate/disulfide mediator was designed and synthesized by employing DFT calculations as a guide. It possesses high transparency to visible light, a very attractive feature for bifacially active transparent DSCs that require a highly transparent counter electrode (CE). Compared to the reported and most promising thiolate/disulfide mediator T(-)/T(2), this new analogous mediator produced a major enhancement in open circuit potential (V(OC)) by about 40 mV and correspondingly a higher power conversion efficiency (η) for DSCs. Furthermore, a highly uniform and transparent (transmittance > 91%) poly(3,4-ethylenedioxythiophene) (PEDOT(BE)) CE was prepared and could efficiently catalyze the reduction of the disulfide. Based on the novel transparent redox couple and PEDOT(BE) CE, a new type of iodine-free and Pt-free transparent bifacial DSC was successfully fabricated. This new bifacial device could not only yield a promising front-illuminated η of 6.07%, but also produce an attractive η as high as 4.35% for rear-side irradiation, which exceeds the rear-illuminated η of 3.93% achieved for the same type of device, employing the dark-colored I(-)/I(3)(-) electrolyte.

Integrated operation of continuous chromatography and biotransformations for the generic high yield production of fine chemicals.

PubMed

Bechtold, Matthias; Makart, Stefan; Heinemann, Matthias; Panke, Sven

2006-06-25

The rapid progress in biocatalysis in the identification and development of enzymes over the last decade has enormously enlarged the chemical reaction space that can be addressed not only in research applications, but also on industrial scale. This enables us to consider even those groups of reactions that are very promising from a synthetic point of view, but suffer from drawbacks on process level, such as an unfavourable position of the reaction equilibrium. Prominent examples stem from the aldolase-catalyzed enantioselective carbon-carbon bond forming reactions, reactions catalyzed by isomerising enzymes, and reactions that are kinetically controlled. On the other hand, continuous chromatography concepts such as the simulating moving bed technology have matured and are increasingly realized on industrial scale for the efficient separation of difficult compound mixtures - including enantiomers - with unprecedented efficiency. We propose that coupling of enzyme reactor and continuous chromatography is a very suitable and potentially generic process concept to address the thermodynamic limitations of a host of promising biotransformations. This way, it should be possible to establish novel in situ product recovery processes of unprecedented efficiency and selectivity that represent a feasible way to recruit novel biocatalysts to the industrial portfolio.

Superfast Near-Infrared Light-Driven Polymer Multilayer Rockets.

PubMed

Wu, Zhiguang; Si, Tieyan; Gao, Wei; Lin, Xiankun; Wang, Joseph; He, Qiang

2016-02-03

A gold nanoshell-functionalized polymer multilayer nanorocket performs self-propulsion upon the irradiation with NIR light in the absence of chemical fuel. Theoretical simulations reveal that the NIR light-triggered self-thermophoresis drives the propulsion of the nanorocket. The nanorocket also displays -efficient NIR light-triggered propulsion in -biofluids and thus holds considerable promise for various potential biomedical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Generation of THz Wave with Orbital Angular Momentum by Graphene Patch Reflectarray

DTIC Science & Technology

2015-07-01

potential to significantly increase spectral efficiency and channel capacity for wireless communication [1]. A few techniques have been reported to...plane wave. The graphene-based OAM generation is very promising for future applications in THz wireless communication . ACKNOWLEDGEMENT This work is... Dyadic Green’s functions and guided surface waves for a surface conductivity model of graphene,” Journal of Applied Physics, vol. 103, no. 6, pp

Au/ZnS core/shell nanocrystals as an efficient anode photocatalyst in direct methanol fuel cells.

PubMed

Chen, Wei-Ta; Lin, Yin-Kai; Yang, Ting-Ting; Pu, Ying-Chih; Hsu, Yung-Jung

2013-10-04

Au/ZnS core/shell nanocrystals with controllable shell thicknesses were synthesized using a cysteine-assisted hydrothermal method. Incorporating Au/ZnS nanocrystals into the traditional Pt-catalyzed half-cell reaction led to a 43.3% increase in methanol oxidation current under light illumination, demonstrating their promising potential for metal/semiconductor hybrid nanocrystals as the anode photocatalyst in direct methanol fuel cells.

Fatigue reduction during aggregated and distributed sequential stimulation.

PubMed

Bergquist, Austin J; Babbar, Vishvek; Ali, Saima; Popovic, Milos R; Masani, Kei

2017-08-01

Transcutaneous neuromuscular electrical stimulation (NMES) can generate muscle contractions for rehabilitation and exercise. However, NMES-evoked contractions are limited by fatigue when they are delivered "conventionally" (CONV) using a single active electrode. Researchers have developed "sequential" (SEQ) stimulation, involving rotation of pulses between multiple "aggregated" (AGGR-SEQ) or "distributed" (DISTR-SEQ) active electrodes, to reduce fatigue (torque-decline) by reducing motor unit discharge rates. The primary objective was to compare fatigue-related outcomes, "potentiation," "variability," and "efficiency" between CONV, AGGR-SEQ, and DISTR-SEQ stimulation of knee extensors in healthy participants. Torque and current were recorded during testing with fatiguing trains using each NMES type under isometric and isokinetic (180°/s) conditions. Compared with CONV stimulation, SEQ techniques reduced fatigue-related outcomes, increased potentiation, did not affect variability, and reduced efficiency. SEQ techniques hold promise for reducing fatigue during NMES-based rehabilitation and exercise; however, optimization is required to improve efficiency. Muscle Nerve 56: 271-281, 2017. © 2016 Wiley Periodicals, Inc.

Oxygen Reduction Reaction on Platinum-Terminated “Onion-structured” Alloy Catalysts

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

Herron, Jeffrey A.; Jiao, Jiao; Hahn, Konstanze

Using periodic, self-consistent density functional theory (GGA-PW91) calculations, a series of onion-structured metal alloys have been investigated for their catalytic performance towards the oxygen reduction reaction (ORR). The onion-structures consist of a varying number of atomic layers of one or two metals each, pseudomorphically deposited on top of one another to form the overall structure. All catalysts studied feature a Pt overlayer, and often consist of at least one Pd layer below the surface. Three distinct ORR mechanisms were analyzed on the close-packed facets of all the structures considered. These mechanisms include a direct route of O2 dissociation and twomore » hydrogen-assisted routes of O–O bond-breaking in peroxyl (OOH) and in hydrogen peroxide (HOOH) intermediates. A thermochemical analysis of the elementary steps provides information on the operating potential, and thereby energy efficiency of each electrocatalyst. A Sabatier analysis of catalytic activity based on thermochemistry of proton/electron transfer steps and activation energy barrier for O–O bond-breaking steps leads to a “volcano” relation between the surfaces’ activity and the binding energy of O. Several of the onion-structured alloys studied here show promise for achieving energy efficiency higher than that of Pt, by being active at potentials higher than the operating potential of Pt. Furthermore, some have at least as good activity as pure Pt at that operating potential. Thus, a number of the onion-structured alloys studied here are promising as cathode electrocatalysts in proton exchange membrane fuel cells.« less

Trade-offs for food production, nature conservation and climate limit the terrestrial carbon dioxide removal potential.

PubMed

Boysen, Lena R; Lucht, Wolfgang; Gerten, Dieter

2017-10-01

Large-scale biomass plantations (BPs) are a common factor in climate mitigation scenarios as they promise double benefits: extracting carbon from the atmosphere and providing a renewable energy source. However, their terrestrial carbon dioxide removal (tCDR) potentials depend on important factors such as land availability, efficiency of capturing biomass-derived carbon and the timing of operation. Land availability is restricted by the demands of future food production depending on yield increases and population growth, by requirements for nature conservation and, with respect to climate mitigation, avoiding unfavourable albedo changes. We integrate these factors in one spatially explicit biogeochemical simulation framework to explore the tCDR opportunity space on land available after these constraints are taken into account, starting either in 2020 or 2050, and lasting until 2100. We find that assumed future needs for nature protection and food production strongly limit tCDR potentials. BPs on abandoned crop and pasture areas (~1,300 Mha in scenarios of either 8.0 billion people and yield gap reductions of 25% until 2020 or 9.5 billion people and yield gap reductions of 50% until 2050) could, theoretically, sequester ~100 GtC in land carbon stocks and biomass harvest by 2100. However, this potential would be ~80% lower if only cropland was available or ~50% lower if albedo decreases were considered as a factor restricting land availability. Converting instead natural forest, shrubland or grassland into BPs could result in much larger tCDR potentials ̶ but at high environmental costs (e.g. biodiversity loss). The most promising avenue for effective tCDR seems to be improvement of efficient carbon utilization pathways, changes in dietary trends or the restoration of marginal lands for the implementation of tCDR. © 2017 John Wiley & Sons Ltd.

Targeted Delivery of siRNA to Activated T Cells via Transferrin-Polyethylenimine (Tf-PEI) as a Potential Therapy of Asthma

PubMed Central

Xie, Yuran; Kim, Na Hyung; Nadithe, Venkatareddy; Schalk, Dana; Thakur, Archana; Kılıç, Ayşe; Lum, Lawrence G.; Bassett, David JP; Merkel, Olivia M

2016-01-01

Asthma is a worldwide health problem. Activated T cells (ATCs) in the lung, particularly T helper 2 cells (Th2), are strongly associated with inducing airway inflammatory responses and chemoattraction of inflammatory cells in asthma. Small interfering RNA (siRNA) as a promising anti-sense molecule can specifically silence inflammation related genes in ATCs, however, lack of safe and efficient siRNA delivery systems limits the application of siRNA as a therapeutic molecule in asthma. Here, we designed a novel pulmonary delivery system of siRNA, transferrin-polyethylenimine (Tf-PEI), to selectively deliver siRNA to ATCs in the lung. Tf-PEI polyplexes demonstrated optimal physicochemical properties such as size, distribution, zeta-potential, and siRNA condensation efficiency. Moreover, in vitro studies showed significantly enhanced cellular uptake and gene knockdown mediated by Tf-PEI polyplexes in human primary ATCs. Biodistribution of polyplexes in a murine asthmatic model confirmed that Tf-PEI polyplexes can efficiently and selectively deliver siRNA to ATCs. In conclusion, the present work proves the feasibility to target ATCs in asthma via Tf receptor. This strategy could potentially be used to design an efficient siRNA delivery system for asthma therapy. PMID:27001893

Targeted delivery of siRNA to activated T cells via transferrin-polyethylenimine (Tf-PEI) as a potential therapy of asthma.

PubMed

Xie, Yuran; Kim, Na Hyung; Nadithe, Venkatareddy; Schalk, Dana; Thakur, Archana; Kılıç, Ayşe; Lum, Lawrence G; Bassett, David J P; Merkel, Olivia M

2016-05-10

Asthma is a worldwide health problem. Activated T cells (ATCs) in the lung, particularly T helper 2 cells (Th2), are strongly associated with inducing airway inflammatory responses and chemoattraction of inflammatory cells in asthma. Small interfering RNA (siRNA) as a promising anti-sense molecule can specifically silence inflammation related genes in ATCs, however, lack of safe and efficient siRNA delivery systems limits the application of siRNA as a therapeutic molecule in asthma. Here, we designed a novel pulmonary delivery system of siRNA, transferrin-polyethylenimine (Tf-PEI), to selectively deliver siRNA to ATCs in the lung. Tf-PEI polyplexes demonstrated optimal physicochemical properties such as size, distribution, zeta-potential, and siRNA condensation efficiency. Moreover, in vitro studies showed significantly enhanced cellular uptake and gene knockdown mediated by Tf-PEI polyplexes in human primary ATCs. Biodistribution of polyplexes in a murine asthmatic model confirmed that Tf-PEI polyplexes can efficiently and selectively deliver siRNA to ATCs. In conclusion, the present work proves the feasibility to target ATCs in asthma via Tf receptor. This strategy could potentially be used to design an efficient siRNA delivery system for asthma therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrophilic 5-Substituted Uracils as Potential Radiosensitizers: A Density Functional Theory Study.

PubMed

Makurat, Samanta; Chomicz-Mańka, Lidia; Rak, Janusz

2016-08-18

Although 5-bromo-2'-deoxyuridine (5BrdU) possesses significant radiosensitizing power in vitro, clinical studies do not confirm any advantages of radiotherapy employing 5BrdU. This situation calls for a continuous search for efficient radiosensitizers. Using the proposed mechanism of radiosensitization by 5BrdU, we propose a series of 5-substituted uracils, XYU, that should undergo efficient dissociative electron attachment. The DFT-calculated thermodynamic and kinetic data concerning the XYU degradations induced by electron addition suggests that some of the scrutinized derivatives have much better characteristics than 5BrdU itself. Synthesis of these promising candidates for radiosensitizers, followed by studies of their radiosensitizing properties in DNA context, and ultimately in cancer cells, are further steps to confirm their potential applicability in anticancer treatment. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficient thermal diode with ballistic spacer

NASA Astrophysics Data System (ADS)

Chen, Shunda; Donadio, Davide; Benenti, Giuliano; Casati, Giulio

2018-03-01

Thermal rectification is of importance not only for fundamental physics, but also for potential applications in thermal manipulations and thermal management. However, thermal rectification effect usually decays rapidly with system size. Here, we show that a mass-graded system, with two diffusive leads separated by a ballistic spacer, can exhibit large thermal rectification effect, with the rectification factor independent of system size. The underlying mechanism is explained in terms of the effective size-independent thermal gradient and the match or mismatch of the phonon bands. We also show the robustness of the thermal diode upon variation of the model's parameters. Our finding suggests a promising way for designing realistic efficient thermal diodes.

Proneural transcription factor Atoh1 drives highly efficient differentiation of human pluripotent stem cells into dopaminergic neurons.

PubMed

Sagal, Jonathan; Zhan, Xiping; Xu, Jinchong; Tilghman, Jessica; Karuppagounder, Senthilkumar S; Chen, Li; Dawson, Valina L; Dawson, Ted M; Laterra, John; Ying, Mingyao

2014-08-01

Human pluripotent stem cells (PSCs) are a promising cell resource for various applications in regenerative medicine. Highly efficient approaches that differentiate human PSCs into functional lineage-specific neurons are critical for modeling neurological disorders and testing potential therapies. Proneural transcription factors are crucial drivers of neuron development and hold promise for driving highly efficient neuronal conversion in PSCs. Here, we study the functions of proneural transcription factor Atoh1 in the neuronal differentiation of PSCs. We show that Atoh1 is induced during the neuronal conversion of PSCs and that ectopic Atoh1 expression is sufficient to drive PSCs into neurons with high efficiency. Atoh1 induction, in combination with cell extrinsic factors, differentiates PSCs into functional dopaminergic (DA) neurons with >80% purity. Atoh1-induced DA neurons recapitulate key biochemical and electrophysiological features of midbrain DA neurons, the degeneration of which is responsible for clinical symptoms in Parkinson's disease (PD). Atoh1-induced DA neurons provide a reliable disease model for studying PD pathogenesis, such as neurotoxin-induced neurodegeneration in PD. Overall, our results determine the role of Atoh1 in regulating neuronal differentiation and neuron subtype specification of human PSCs. Our Atoh1-mediated differentiation approach will enable large-scale applications of PD patient-derived midbrain DA neurons in mechanistic studies and drug screening for both familial and sporadic PD. ©AlphaMed Press.

One-step Conjugation of Glycyrrhetinic Acid to Cationic Polymers for High-performance Gene Delivery to Cultured Liver Cell.

PubMed

Cong, Yue; Shi, Bingyang; Lu, Yiqing; Wen, Shihui; Chung, Roger; Jin, Dayong

2016-02-23

Gene therapies represent a promising therapeutic route for liver cancers, but major challenges remain in the design of safe and efficient gene-targeting delivery systems. For example, cationic polymers show good transfection efficiency as gene carriers, but are hindered by cytotoxicity and non-specific targeting. Here we report a versatile method of one-step conjugation of glycyrrhetinic acid (GA) to reduce cytotoxicity and improve the cultured liver cell -targeting capability of cationic polymers. We have explored a series of cationic polymer derivatives by coupling different ratios of GA to polypropylenimine (PPI) dendrimer. These new gene carriers (GA-PPI dendrimer) were systematically characterized by UV-vis,(1)H NMR titration, electron microscopy, zeta potential, dynamic light-scattering, gel electrophoresis, confocal microscopy and flow cytometry. We demonstrate that GA-PPI dendrimers can efficiently load and protect pDNA, via formation of nanostructured GA-PPI/pDNA polyplexes. With optimal GA substitution degree (6.31%), GA-PPI dendrimers deliver higher liver cell transfection efficiency (43.5% vs 22.3%) and lower cytotoxicity (94.3% vs 62.5%, cell viability) than the commercial bench-mark DNA carrier bPEI (25 kDa) with cultured liver model cells (HepG2). There results suggest that our new GA-PPI dendrimer are a promising candidate gene carrier for targeted liver cancer therapy.

One-step Conjugation of Glycyrrhetinic Acid to Cationic Polymers for High-performance Gene Delivery to Cultured Liver Cell

PubMed Central

Cong, Yue; Shi, Bingyang; Lu, Yiqing; Wen, Shihui; Chung, Roger; Jin, Dayong

2016-01-01

Gene therapies represent a promising therapeutic route for liver cancers, but major challenges remain in the design of safe and efficient gene-targeting delivery systems. For example, cationic polymers show good transfection efficiency as gene carriers, but are hindered by cytotoxicity and non-specific targeting. Here we report a versatile method of one-step conjugation of glycyrrhetinic acid (GA) to reduce cytotoxicity and improve the cultured liver cell -targeting capability of cationic polymers. We have explored a series of cationic polymer derivatives by coupling different ratios of GA to polypropylenimine (PPI) dendrimer. These new gene carriers (GA-PPI dendrimer) were systematically characterized by UV-vis,1H NMR titration, electron microscopy, zeta potential, dynamic light-scattering, gel electrophoresis, confocal microscopy and flow cytometry. We demonstrate that GA-PPI dendrimers can efficiently load and protect pDNA, via formation of nanostructured GA-PPI/pDNA polyplexes. With optimal GA substitution degree (6.31%), GA-PPI dendrimers deliver higher liver cell transfection efficiency (43.5% vs 22.3%) and lower cytotoxicity (94.3% vs 62.5%, cell viability) than the commercial bench-mark DNA carrier bPEI (25kDa) with cultured liver model cells (HepG2). There results suggest that our new GA-PPI dendrimer are a promising candidate gene carrier for targeted liver cancer therapy. PMID:26902258

Tantalum Sulfide Nanosheets as a Theranostic Nanoplatform for Computed Tomography Imaging-Guided Combinatorial Chemo-Photothermal Therapy.

PubMed

Liu, Yanlan; Ji, Xiaoyuan; Liu, Jianhua; Tong, Winnie W L; Askhatova, Diana; Shi, Jinjun

2017-10-19

Near-infrared (NIR)-absorbing metal-based nanomaterials have shown tremendous potential for cancer therapy, given their facile and controllable synthesis, efficient photothermal conversion, capability of spatiotemporal-controlled drug delivery, and intrinsic imaging function. Tantalum (Ta) is among the most biocompatible metals and arouses negligible adverse biological responses in either oxidized or reduced forms, and thus Ta-derived nanomaterials represent promising candidates for biomedical applications. However, Ta-based nanomaterials by themselves have not been explored for NIR-mediated photothermal ablation therapy. In this work, we report an innovative Ta-based multifunctional nanoplatform composed of biocompatible tantalum sulfide (TaS 2 ) nanosheets (NSs) for simultaneous NIR hyperthermia, drug delivery, and computed tomography (CT) imaging. The TaS 2 NSs exhibit multiple unique features including (i) efficient NIR light-to-heat conversion with a high photothermal conversion efficiency of 39%. (ii) high drug loading (177% by weight), (iii) controlled drug release triggered by NIR light and moderate acidic pH, (iv) high tumor accumulation via heat-enhanced tumor vascular permeability, (v) complete tumor ablation and negligible side effects, and (vi) comparable CT imaging contrast efficiency to the widely clinically used agent iobitridol. We expect that this multifunctional NS platform can serve as a promising candidate for imaging-guided cancer therapy and selection of cancer patients with high tumor accumulation.

Production of liquid fuels out of plant biomass and refuse: Methods, cost, potential (in MIXED)

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

Woick, B.; Friedrich, R.

1981-09-01

Different ways of producing biomass and its conversion into high grade fuel for vehicles are reviewed with particular reference to physical and geographical factors, pertaining in the Federal Republic of Germany (FRG). Even with the potentially small amount of biomass in the FRG, the fueling of diesel engines with rape oil or modified ethanol, which can be obtained from any cellulosic feedstock, seems to pose the fewest difficulties and promises greatest efficiency. However, the amount of fuel produced from biomass can probably only meet a very small percentage of the total amount required.

Toward a High-Efficient Utilization of Solar Radiation by Quad-Band Solar Spectral Splitting.

PubMed

Cao, Feng; Huang, Yi; Tang, Lu; Sun, Tianyi; Boriskina, Svetlana V; Chen, Gang; Ren, Zhifeng

2016-12-01

The promising quad-band solar spectral splitter incorporates the properties of the optical filter and the spectrally selective solar thermal absorber can direct PV band to PV modules and absorb thermal band energy for thermal process with low thermal losses. It provides a new strategy for spectral splitting and offers potential ways for hybrid PVT system design. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Watt-level dysprosium fiber laser at 315 μm with 73% slope efficiency

NASA Astrophysics Data System (ADS)

Woodward, R. I.; Majewski, M. R.; Bharathan, G.; Hudson, D. D.; Fuerbach, A.; Jackson, S. D.

2018-04-01

Rare-earth-doped fiber lasers are emerging as promising high-power mid-infrared sources for the 2.6-3.0 {\\mu}m and 3.3-3.8 {\\mu}m regions based on erbium and holmium ions. The intermediate wavelength range, however, remains vastly underserved, despite prospects for important manufacturing and defense applications. Here, we demonstrate the potential of dysprosium-doped fiber to solve this problem, with a simple in-band pumped grating-stabilized linear cavity generating up to 1.06 W at 3.15 {\\mu}m. A slope efficiency of 73% with respect to launched power (77% relative to absorbed power) is achieved: the highest value for any mid-infrared fiber laser to date, to the best of our knowledge. Opportunities for further power and efficiency scaling are also discussed.

Recent Development of Plasmonic Resonance-Based Photocatalysis and Photovoltaics for Solar Utilization.

PubMed

Fan, Wenguang; Leung, Michael K H

2016-02-02

Increasing utilization of solar energy is an effective strategy to tackle our energy and energy-related environmental issues. Both solar photocatalysis (PC) and solar photovoltaics (PV) have high potential to develop technologies of many practical applications. Substantial research efforts are devoted to enhancing visible light activation of the photoelectrocatalytic reactions by various modifications of nanostructured semiconductors. This review paper emphasizes the recent advancement in material modifications by means of the promising localized surface plasmonic resonance (LSPR) mechanisms. The principles of LSPR and its effects on the photonic efficiency of PV and PC are discussed here. Many research findings reveal the promise of Au and Ag plasmonic nanoparticles (NPs). Continual investigation for increasing the stability of the plasmonic NPs will be fruitful.

Efficient synthetic methods for the installation of boron-nitrogen bonds in conjugated organic molecules.

PubMed

Morgan, Matthew M; Piers, Warren E

2016-04-14

Polycyclic aromatic hydrocarbons in which one or more CC units have been replaced by isoelectronic BN units have attracted interest as potentially improved organic materials in various devices. This promise has been hampered by a lack of access to gram quantities of these materials. However, the exploitation of keystone reactions such as ring closing metathesis, borylative cyclization of amino styrenes and electrophilic borylation has lead to strategies for access to workable amounts of material. These strategies can be augmented by judicious postfunctionalization reactions to diversify the library of materials available. This Frontier article highlights some of the recent successes and shows that the long promised applications of BN-doped PAHs are beginning to be explored in a meaningful way.

Cu2O/CuO Bilayered Composite as a High-Efficiency Photocathode for Photoelectrochemical Hydrogen Evolution Reaction

PubMed Central

Yang, Yang; Xu, Di; Wu, Qingyong; Diao, Peng

2016-01-01

Solar powered hydrogen evolution reaction (HER) is one of the key reactions in solar-to-chemical energy conversion. It is desirable to develop photocathodic materials that exhibit high activity toward photoelectrochemical (PEC) HER at more positive potentials because a higher potential means a lower overpotential for HER. In this work, the Cu2O/CuO bilayered composites were prepared by a facile method that involved an electrodeposition and a subsequent thermal oxidation. The resulting Cu2O/CuO bilayered composites exhibited a surprisingly high activity and good stability toward PEC HER, expecially at high potentials in alkaline solution. The photocurrent density for HER was 3.15 mA·cm−2 at the potential of 0.40 V vs. RHE, which was one of the two highest reported at the same potential on copper-oxide-based photocathode. The high photoactivity of the bilayered composite was ascribed to the following three advantages of the Cu2O/CuO heterojunction: (1) the broadened light absorption band that made more efficient use of solar energy, (2) the large space-charge-region potential that enabled a high efficiency for electron-hole separation, and (3) the high majority carrier density that ensured a faster charge transportation rate. This work reveals the potential of the Cu2O/CuO bilayered composite as a promising photocathodic material for solar water splitting. PMID:27748380

CRISPR-Cas9 therapeutics in cancer: promising strategies and present challenges.

PubMed

Yi, Lang; Li, Jinming

2016-12-01

Cancer is characterized by multiple genetic and epigenetic alterations that drive malignant cell proliferation and confer chemoresistance. The ability to correct or ablate such mutations holds immense promise for combating cancer. Recently, because of its high efficiency and accuracy, the CRISPR-Cas9 genome editing technique has been widely used in cancer therapeutic explorations. Several studies used CRISPR-Cas9 to directly target cancer cell genomic DNA in cellular and animal cancer models which have shown therapeutic potential in expanding our anticancer protocols. Moreover, CRISPR-Cas9 can also be employed to fight oncogenic infections, explore anticancer drugs, and engineer immune cells and oncolytic viruses for cancer immunotherapeutic applications. Here, we summarize these preclinical CRISPR-Cas9-based therapeutic strategies against cancer, and discuss the challenges and improvements in translating therapeutic CRISPR-Cas9 into clinical use, which will facilitate better application of this technique in cancer research. Further, we propose potential directions of the CRISPR-Cas9 system in cancer therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

Nanomanufacturing : nano-structured materials made layer-by-layer.

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

Cox, James V.; Cheng, Shengfeng; Grest, Gary Stephen

Large-scale, high-throughput production of nano-structured materials (i.e. nanomanufacturing) is a strategic area in manufacturing, with markets projected to exceed $1T by 2015. Nanomanufacturing is still in its infancy; process/product developments are costly and only touch on potential opportunities enabled by growing nanoscience discoveries. The greatest promise for high-volume manufacturing lies in age-old coating and imprinting operations. For materials with tailored nm-scale structure, imprinting/embossing must be achieved at high speeds (roll-to-roll) and/or over large areas (batch operation) with feature sizes less than 100 nm. Dispersion coatings with nanoparticles can also tailor structure through self- or directed-assembly. Layering films structured with thesemore » processes have tremendous potential for efficient manufacturing of microelectronics, photovoltaics and other topical nano-structured devices. This project is designed to perform the requisite R and D to bring Sandia's technology base in computational mechanics to bear on this scale-up problem. Project focus is enforced by addressing a promising imprinting process currently being commercialized.« less

A reconfigurable waveguide for energy-efficient transmission and local manipulation of information in a nanomagnetic device

NASA Astrophysics Data System (ADS)

Haldar, Arabinda; Kumar, Dheeraj; Adeyeye, Adekunle Olusola

2016-05-01

Spin-wave-based devices promise to usher in an era of low-power computing where information is carried by the precession of the electrons' spin instead of dissipative translation of their charge. This potential is, however, undermined by the need for a bias magnetic field, which must remain powered on to maintain an anisotropic device characteristic. Here, we propose a reconfigurable waveguide design that can transmit and locally manipulate spin waves without the need for any external bias field once initialized. We experimentally demonstrate the transmission of spin waves in straight as well as curved waveguides without a bias field, which has been elusive so far. Furthermore, we experimentally show a binary gating of the spin-wave signal by controlled switching of the magnetization, locally, in the waveguide. The results have potential implications in high-density integration and energy-efficient operation of nanomagnetic devices at room temperature.

A graphene oxide/amidoxime hydrogel for enhanced uranium capture

PubMed Central

Wang, Feihong; Li, Hongpeng; Liu, Qi; Li, Zhanshuang; Li, Rumin; Zhang, Hongsen; Liu, Lianhe; Emelchenko, G. A.; Wang, Jun

2016-01-01

The efficient development of selective materials for the recovery of uranium from nuclear waste and seawater is necessary for their potential application in nuclear fuel and the mitigation of nuclear pollution. In this work, a graphene oxide/amidoxime hydrogel (AGH) exhibits a promising adsorption performance for uranium from various aqueous solutions, including simulated seawater. We show high adsorption capacities (Qm = 398.4 mg g−1) and high % removals at ppm or ppb levels in aqueous solutions for uranium species. In the presence of high concentrations of competitive ions such as Mg2+, Ca2+, Ba2+ and Sr2+, AGH displays an enhanced selectivity for uranium. For low uranium concentrations in simulated seawater, AGH binds uranium efficiently and selectively. The results presented here reveal that the AGH is a potential adsorbent for remediating nuclear industrial effluent and adsorbing uranium from seawater. PMID:26758649

A molecular theory for optimal blue energy extraction by electrical double layer expansion

DOE PAGES

Kong, Xian; Gallegos, Alejandro; Lu, Diannan; ...

2015-08-19

We proposed the electrical double layer expansion (CDLE) as a promising alternative to reverse electrodialysis (RED) and pressure retarded osmosis (PRO) processes for extracting osmotic power generated by the salinity difference between freshwater and seawater. The performance of the CDLE process is sensitive to the configuration of porous electrodes and operation parameters for ion extraction and release cycles. In our work, we use a classical density functional theory (CDFT) to examine how the electrode pore size and charging/discharging potentials influence the thermodynamic efficiency of the CDLE cycle. The existence of an optimal charging potential that maximizes the energy output formore » a given pore configuration is predicted, which varies substantially with the pore size, especially when it is smaller than 2 nm. Finally, the thermodynamic efficiency is maximized when the electrode has a pore size about twice the ion diameter.« less

Quantum-Dot-Based Solar Cells: Recent Advances, Strategies, and Challenges.

PubMed

Kim, Mee Rahn; Ma, Dongling

2015-01-02

Among next-generation photovoltaic systems requiring low cost and high efficiency, quantum dot (QD)-based solar cells stand out as a very promising candidate because of the unique and versatile characteristics of QDs. The past decade has already seen rapid conceptual and technological advances on various aspects of QD solar cells, and diverse opportunities, which QDs can offer, predict that there is still ample room for further development and breakthroughs. In this Perspective, we first review the attractive advantages of QDs, such as size-tunable band gaps and multiple exciton generation (MEG), beneficial to solar cell applications. We then analyze major strategies, which have been extensively explored and have largely contributed to the most recent and significant achievements in QD solar cells. Finally, their high potential and challenges are discussed. In particular, QD solar cells are considered to hold immense potential to overcome the theoretical efficiency limit of 31% for single-junction cells.

Energy Efficiency of Biogas Produced from Different Biomass Sources

NASA Astrophysics Data System (ADS)

Begum, Shahida; Nazri, A. H.

2013-06-01

Malaysia has different sources of biomass like palm oil waste, agricultural waste, cow dung, sewage waste and landfill sites, which can be used to produce biogas and as a source of energy. Depending on the type of biomass, the biogas produced can have different calorific value. At the same time the energy, being used to produce biogas is dependent on transportation distance, means of transportation, conversion techniques and for handling of raw materials and digested residues. An energy systems analysis approach based on literature is applied to calculate the energy efficiency of biogas produced from biomass. Basically, the methodology is comprised of collecting data, proposing locations and estimating the energy input needed to produce biogas and output obtained from the generated biogas. The study showed that palm oil and municipal solid waste is two potential sources of biomass. The energy efficiency of biogas produced from palm oil residues and municipal solid wastes is 1.70 and 3.33 respectively. Municipal solid wastes have the higher energy efficiency due to less transportation distance and electricity consumption. Despite the inherent uncertainties in the calculations, it can be concluded that the energy potential to use biomass for biogas production is a promising alternative.

Effect of Yb(3+) on the Crystal Structural Modification and Photoluminescence Properties of GGAG:Ce(3+).

PubMed

Luo, Zhao-Hua; Liu, Yong-Fu; Zhang, Chang-Hua; Zhang, Jian-Xin; Qin, Hai-Ming; Jiang, Hao-Chuan; Jiang, Jun

2016-03-21

Gadolinium gallium aluminum garnet (GGAG) is a very promising host for the highly efficient luminescence of Ce(3+) and shows potential in radiation detection applications. However, the thermodynamically metastable structure would be slanted against it from getting high transparency. To stabilize the crystal structure of GGAG, Yb(3+) ions were codoped at the Gd(3+) site. It is found that the decomposition of garnet was suppressed and the transparency of GGAG ceramic was evidently improved. Moreover, the photoluminescence of GGAG:Ce(3+),xYb(3+) with different Yb(3+) contents has been investigated. When the Ce(3+) ions were excited under 475 nm, a typical near-infrared region emission of Yb(3+) ions can be observed, where silicon solar cells have the strongest absorption. Basing on the lifetimes of Ce(3+) ions in the GGAG:Ce(3+),xYb(3+) sample, the transfer efficiency from Ce(3+) to Yb(3+) and the theoretical internal quantum efficiency can be calculated and reach up to 86% and 186%, respectively. This would make GGAG:Ce(3+),Yb(3+) a potential attractive downconversion candidate for improving the energy conversion efficiency of crystalline silicon (c-Si) solar cells.

High-Efficiency Silicon/Organic Heterojunction Solar Cells with Improved Junction Quality and Interface Passivation.

PubMed

He, Jian; Gao, Pingqi; Ling, Zhaoheng; Ding, Li; Yang, Zhenhai; Ye, Jichun; Cui, Yi

2016-12-27

Silicon/organic heterojunction solar cells (HSCs) based on conjugated polymers, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and n-type silicon (n-Si) have attracted wide attention due to their potential advantages of high efficiency and low cost. However, the state-of-the-art efficiencies are still far from satisfactory due to the inferior junction quality. Here, facile treatments were applied by pretreating the n-Si wafer in tetramethylammonium hydroxide (TMAH) solution and using a capping copper iodide (CuI) layer on the PEDOT:PSS layer to achieve a high-quality Schottky junction. Detailed photoelectric characteristics indicated that the surface recombination was greatly suppressed after TMAH pretreatment, which increased the thickness of the interfacial oxide layer. Furthermore, the CuI capping layer induced a strong inversion layer near the n-Si surface, resulting in an excellent field effect passivation. With the collaborative improvements in the interface chemical and electrical passivation, a competitive open-circuit voltage of 0.656 V and a high fill factor of 78.1% were achieved, leading to a stable efficiency of over 14.3% for the planar n-Si/PEDOT:PSS HSCs. Our findings suggest promising strategies to further exploit the full voltage as well as efficiency potentials for Si/organic solar cells.

Fast electrosynthesis of Fe-containing layered double hydroxide arrays toward highly efficient electrocatalytic oxidation reactions† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc02417j

PubMed Central

Li, Zhenhua; An, Hongli; Wang, Zixuan; Xu, Simin; Evans, David G.; Duan, Xue

2015-01-01

A new electrochemical synthesis route was developed for the fabrication of Fe-containing layered double hydroxide (MFe-LDHs, M = Ni, Co and Li) hierarchical nanoarrays, which exhibit highly-efficient electrocatalytic performances for the oxidation reactions of several small molecules (water, hydrazine, methanol and ethanol). Ultrathin MFe-LDH nanoplatelets (200–300 nm in lateral length; 8–12 nm in thickness) perpendicular to the substrate surface are directly prepared within hundreds of seconds (<300 s) under cathodic potential. The as-obtained NiFe-LDH nanoplatelet arrays display promising behavior in the oxygen evolution reaction (OER), giving rise to a rather low overpotential (0.224 V) at 10.0 mA cm–2 with largely enhanced stability, much superior to previously reported electro-oxidation catalysts as well as the state-of-the-art Ir/C catalyst. Furthermore, the MFe-LDH nanoplatelet arrays can also efficiently catalyze several other fuel molecules’ oxidation (e.g., hydrazine, methanol and ethanol), delivering a satisfactory electrocatalytic activity and a high operation stability. In particular, this preparation method of Fe-containing LDHs is amenable to fast, effective and large-scale production, and shows promising applications in water splitting, fuel cells and other clean energy devices. PMID:29435211

Highly Efficient Flexible Quantum Dot Solar Cells with Improved Electron Extraction Using MgZnO Nanocrystals.

PubMed

Zhang, Xiaoliang; Santra, Pralay Kanti; Tian, Lei; Johansson, Malin B; Rensmo, Håkan; Johansson, Erik M J

2017-08-22

Colloidal quantum dot (CQD) solar cells have high potential for realizing an efficient and lightweight energy supply for flexible or wearable electronic devices. To achieve highly efficient and flexible CQD solar cells, the electron transport layer (ETL), extracting electrons from the CQD solid layer, needs to be processed at a low-temperature and should also suppress interfacial recombination. Herein, a highly stable MgZnO nanocrystal (MZO-NC) layer is reported for efficient flexible PbS CQD solar cells. Solar cells fabricated with MZO-NC ETL give a high power conversion efficiency (PCE) of 10.4% and 9.4%, on glass and flexible plastic substrates, respectively. The reported flexible CQD solar cell has the record efficiency to date of flexible CQD solar cells. Detailed theoretical simulations and extensive characterizations reveal that the MZO-NCs significantly enhance charge extraction from CQD solids and diminish the charge accumulation at the ETL/CQD interface, suppressing charge interfacial recombination. These important results suggest that the low-temperature processed MZO-NCs are very promising for use in efficient flexible solar cells or other flexible optoelectronic devices.

Chitosan-based water-propelled micromotors with strong antibacterial activity.

PubMed

Delezuk, Jorge A M; Ramírez-Herrera, Doris E; Esteban-Fernández de Ávila, Berta; Wang, Joseph

2017-02-09

A rapid and efficient micromotor-based bacteria killing strategy is described. The new antibacterial approach couples the attractive antibacterial properties of chitosan with the efficient water-powered propulsion of magnesium (Mg) micromotors. These Janus micromotors consist of Mg microparticles coated with the biodegradable and biocompatible polymers poly(lactic-co-glycolic acid) (PLGA), alginate (Alg) and chitosan (Chi), with the latter responsible for the antibacterial properties of the micromotor. The distinct speed and efficiency advantages of the new micromotor-based environmentally friendly antibacterial approach have been demonstrated in various control experiments by treating drinking water contaminated with model Escherichia coli (E. coli) bacteria. The new dynamic antibacterial strategy offers dramatic improvements in the antibacterial efficiency, compared to static chitosan-coated microparticles (e.g., 27-fold enhancement), with a 96% killing efficiency within 10 min. Potential real-life applications of these chitosan-based micromotors for environmental remediation have been demonstrated by the efficient treatment of seawater and fresh water samples contaminated with unknown bacteria. Coupling the efficient water-driven propulsion of such biodegradable and biocompatible micromotors with the antibacterial properties of chitosan holds great considerable promise for advanced antimicrobial water treatment operation.

Solar water splitting by photovoltaic-electrolysis with a solar-to-hydrogen efficiency over 30%

PubMed Central

Jia, Jieyang; Seitz, Linsey C.; Benck, Jesse D.; Huo, Yijie; Chen, Yusi; Ng, Jia Wei Desmond; Bilir, Taner; Harris, James S.; Jaramillo, Thomas F.

2016-01-01

Hydrogen production via electrochemical water splitting is a promising approach for storing solar energy. For this technology to be economically competitive, it is critical to develop water splitting systems with high solar-to-hydrogen (STH) efficiencies. Here we report a photovoltaic-electrolysis system with the highest STH efficiency for any water splitting technology to date, to the best of our knowledge. Our system consists of two polymer electrolyte membrane electrolysers in series with one InGaP/GaAs/GaInNAsSb triple-junction solar cell, which produces a large-enough voltage to drive both electrolysers with no additional energy input. The solar concentration is adjusted such that the maximum power point of the photovoltaic is well matched to the operating capacity of the electrolysers to optimize the system efficiency. The system achieves a 48-h average STH efficiency of 30%. These results demonstrate the potential of photovoltaic-electrolysis systems for cost-effective solar energy storage. PMID:27796309

Solar water splitting by photovoltaic-electrolysis with a solar-to-hydrogen efficiency over 30.

PubMed

Jia, Jieyang; Seitz, Linsey C; Benck, Jesse D; Huo, Yijie; Chen, Yusi; Ng, Jia Wei Desmond; Bilir, Taner; Harris, James S; Jaramillo, Thomas F

2016-10-31

Hydrogen production via electrochemical water splitting is a promising approach for storing solar energy. For this technology to be economically competitive, it is critical to develop water splitting systems with high solar-to-hydrogen (STH) efficiencies. Here we report a photovoltaic-electrolysis system with the highest STH efficiency for any water splitting technology to date, to the best of our knowledge. Our system consists of two polymer electrolyte membrane electrolysers in series with one InGaP/GaAs/GaInNAsSb triple-junction solar cell, which produces a large-enough voltage to drive both electrolysers with no additional energy input. The solar concentration is adjusted such that the maximum power point of the photovoltaic is well matched to the operating capacity of the electrolysers to optimize the system efficiency. The system achieves a 48-h average STH efficiency of 30%. These results demonstrate the potential of photovoltaic-electrolysis systems for cost-effective solar energy storage.

Transmission and Distribution Efficiency Improvement Rearch and Development Survey.

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

Brooks, C.L.; Westinghouse Electric Corporation. Advanced Systems Technology.

Purpose of this study was to identify and quantify those technologies for improving transmission and distribution (T and D) system efficiency that could provide the greatest benefits for utility customers in the Pacific Northwest. Improving the efficiency of transmission and distribution systems offers a potential source of conservation within the utility sector. An extensive review of this field resulted in a list of 49 state-of-the-art technologies and 39 future technologies. Of these, 15 from the former list and 7 from the latter were chosen as the most promising and then submitted to an evaluative test - a modeled sample systemmore » for Benton County PUD, a utility with characteristics typical of a BPA customer system. Reducing end-use voltage on secondary distribution systems to decrease the energy consumption of electrical users when possible, called ''Conservation Voltage Reduction,'' was found to be the most cost effective state-of-the-art technology. Voltampere reactive (var) optimization is a similarly cost effective alternative. The most significant reduction in losses on the transmission and distribution system would be achieved through the replacement of standard transformers with high efficiency transformers, such as amorphous steel transformers. Of the future technologies assessed, the ''Distribution Static VAR Generator'' appears to have the greatest potential for technological breakthroughs and, therefore in time, commercialization. ''Improved Dielectric Materials,'' with a relatively low cost and high potential for efficiency improvement, warrant R and D consideration. ''Extruded Three-Conductor Cable'' and ''Six- and Twelve-Phase Transmission'' programs provide only limited gains in efficiency and applicability and are therefore the least cost effective.« less

High-performance flat-panel solar thermoelectric generators with high thermal concentration.

PubMed

Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

2011-05-01

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m(-2)) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity. © 2011 Macmillan Publishers Limited. All rights reserved

Mesoporous composite nanoparticles for dual-modality ultrasound/magnetic resonance imaging and synergistic chemo-/thermotherapy against deep tumors.

PubMed

Zhang, Nan; Wang, Ronghui; Hao, Junnian; Yang, Yang; Zou, Hongmi; Wang, Zhigang

2017-01-01

High-intensity focused ultrasound (HIFU) is a promising and noninvasive treatment for solid tumors, which has been explored for potential clinical applications. However, the clinical applications of HIFU for large and deep tumors such as hepatocellular carcinoma (HCC) are severely limited by unsatisfactory imaging guidance, long therapeutic times, and damage to normal tissue around the tumor due to the high power applied. In this study, we developed doxorubicin/perfluorohexane-encapsulated hollow mesoporous Prussian blue nanoparticles (HMPBs-DOX/PFH) as theranostic agents, which can effectively guide HIFU therapy and enhance its therapeutic effects in combination with chemotherapy, by decreasing the cavitation threshold. We investigated the effects of this agent on ultrasound and magnetic resonance imaging in vitro and in vivo. In addition, we showed a highly efficient HIFU therapeutic effect against HCC tumors, as well as controlled drug release, owing to the phase-transitional performance of the PFH. We therefore conclude that HMPB-DOX/PFH is a safe and efficient nanoplatform, which holds significant promise for cancer theranostics against deep tumors in clinical settings.

Mesoporous composite nanoparticles for dual-modality ultrasound/magnetic resonance imaging and synergistic chemo-/thermotherapy against deep tumors

PubMed Central

Zhang, Nan; Wang, Ronghui; Hao, Junnian; Yang, Yang; Zou, Hongmi; Wang, Zhigang

2017-01-01

High-intensity focused ultrasound (HIFU) is a promising and noninvasive treatment for solid tumors, which has been explored for potential clinical applications. However, the clinical applications of HIFU for large and deep tumors such as hepatocellular carcinoma (HCC) are severely limited by unsatisfactory imaging guidance, long therapeutic times, and damage to normal tissue around the tumor due to the high power applied. In this study, we developed doxorubicin/perfluorohexane-encapsulated hollow mesoporous Prussian blue nanoparticles (HMPBs-DOX/PFH) as theranostic agents, which can effectively guide HIFU therapy and enhance its therapeutic effects in combination with chemotherapy, by decreasing the cavitation threshold. We investigated the effects of this agent on ultrasound and magnetic resonance imaging in vitro and in vivo. In addition, we showed a highly efficient HIFU therapeutic effect against HCC tumors, as well as controlled drug release, owing to the phase-transitional performance of the PFH. We therefore conclude that HMPB-DOX/PFH is a safe and efficient nanoplatform, which holds significant promise for cancer theranostics against deep tumors in clinical settings. PMID:29042775

Algae Derived Biofuel

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

Jahan, Kauser

One of the most promising fuel alternatives is algae biodiesel. Algae reproduce quickly, produce oils more efficiently than crop plants, and require relatively few nutrients for growth. These nutrients can potentially be derived from inexpensive waste sources such as flue gas and wastewater, providing a mutual benefit of helping to mitigate carbon dioxide waste. Algae can also be grown on land unsuitable for agricultural purposes, eliminating competition with food sources. This project focused on cultivating select algae species under various environmental conditions to optimize oil yield. Membrane studies were also conducted to transfer carbon di-oxide more efficiently. An LCA studymore » was also conducted to investigate the energy intensive steps in algae cultivation.« less

Applications of Tunable TiO2 Nanotubes as Nanotemplate and Photovoltaic Device

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

Li, Dongdong; Chang, Pai-Chun; Chien, Chung-Jen

2010-10-26

Highly ordered anodic titanium oxide (ATO) TiO{sub 2} nanotube film has been synthesized via a typical two-step anodization method. Following a reductive doping approach, metallic materials (copper and nickel) can be efficiently electrodeposited into the nanotubes. This versatile process yields reproducible tubular structures in ATO membranes, because of the conductive nature of crystallized TiO{sub 2}, yielding promising potential for nanotemplate applications. In this paper, we present a dye-sensitized solar cell constructed by employing such ATO films. It is observed that the reductive doping treatment can also enhance the solar cell’s short current density and fill factor, resulting in an improvedmore » energy conversion efficiency.« less

Downdating a time-varying square root information filter

NASA Technical Reports Server (NTRS)

Muellerschoen, Ronald J.

1990-01-01

A new method to efficiently downdate an estimate and covariance generated by a discrete time Square Root Information Filter (SRIF) is presented. The method combines the QR factor downdating algorithm of Gill and the decentralized SRIF algorithm of Bierman. Efficient removal of either measurements or a priori information is possible without loss of numerical integrity. Moreover, the method includes features for detecting potential numerical degradation. Performance on a 300 parameter system with 5800 data points shows that the method can be used in real time and hence is a promising tool for interactive data analysis. Additionally, updating a time-varying SRIF filter with either additional measurements or a priori information proceeds analogously.

Tracking historical increases in nitrogen-driven crop production possibilities

NASA Astrophysics Data System (ADS)

Mueller, N. D.; Lassaletta, L.; Billen, G.; Garnier, J.; Gerber, J. S.

2015-12-01

The environmental costs of nitrogen use have prompted a focus on improving the efficiency of nitrogen use in the global food system, the primary source of nitrogen pollution. Typical approaches to improving agricultural nitrogen use efficiency include more targeted field-level use (timing, placement, and rate) and modification of the crop mix. However, global efficiency gains can also be achieved by improving the spatial allocation of nitrogen between regions or countries, due to consistent diminishing returns at high nitrogen use. This concept is examined by constructing a tradeoff frontier (or production possibilities frontier) describing global crop protein yield as a function of applied nitrogen from all sources, given optimal spatial allocation. Yearly variation in country-level input-output nitrogen budgets are utilized to parameterize country-specific hyperbolic yield-response models. Response functions are further characterized for three ~15-year eras beginning in 1961, and series of calculations uses these curves to simulate optimal spatial allocation in each era and determine the frontier. The analyses reveal that excess nitrogen (in recent years) could be reduced by ~40% given optimal spatial allocation. Over time, we find that gains in yield potential and in-country nitrogen use efficiency have led to increases in the global nitrogen production possibilities frontier. However, this promising shift has been accompanied by an actual spatial distribution of nitrogen use that has become less optimal, in an absolute sense, relative to the frontier. We conclude that examination of global production possibilities is a promising approach to understanding production constraints and efficiency opportunities in the global food system.

Three-Dimensional Array of TiN@Pt3Cu Nanowires as an Efficient Porous Electrode for the Lithium-Oxygen Battery.

PubMed

Luo, Wen-Bin; Pham, Thien Viet; Guo, Hai-Peng; Liu, Hua-Kun; Dou, Shi-Xue

2017-02-28

The nonaqueous lithium-oxygen battery is a promising candidate as a next-generation energy storage system because of its potentially high energy density (up to 2-3 kW kg -1 ), exceeding that of any other existing energy storage system for storing sustainable and clean energy to reduce greenhouse gas emissions and the consumption of nonrenewable fossil fuels. To achieve high round-trip efficiency and satisfactory cycling stability, the air electrode structure and the electrocatalysts play important roles. Here, a 3D array composed of one-dimensional TiN@Pt 3 Cu nanowires was synthesized and employed as a whole porous air electrode in a lithium-oxygen battery. The TiN nanowire was primarily used as an air electrode frame and catalyst support to provide a high electronic conductivity network because of the high-orientation one-dimensional crystalline structure. Meanwhile, deposited icosahedral Pt 3 Cu nanocrystals exhibit highly efficient catalytic activity owing to the abundant {111} active lattice facets and multiple twin boundaries. This porous air electrode comprises a one-dimensional TiN@Pt 3 Cu nanowire array that demonstrates excellent energy conversion efficiency and rate performance in full discharge and charge modes. The discharge capacity is up to 4600 mAh g -1 along with an 84% conversion efficiency at a current density of 0.2 mA cm -2 , and when the current density increased to 0.8 mA cm -2 , the discharge capacity is still greater than 3500 mAh g -1 together with a nearly 70% efficiency. This designed array is a promising bifunctional porous air electrode for lithium-oxygen batteries, forming a continuous conductive and high catalytic activity network to facilitate rapid gas and electrolyte diffusion and catalytic reaction throughout the whole energy conversion process.

Optimization of electrode characteristics for the Br₂/H₂ redox flow cell

DOE PAGES

Tucker, Michael C.; Cho, Kyu Taek; Weber, Adam Z.; ...

2014-10-17

The Br₂/H₂ redox flow cell shows promise as a high-power, low-cost energy storage device. The effect of various aspects of material selection, processing, and assembly of electrodes on the operation, performance, and efficiency of the system is determined. In particular, (+) electrode thickness, cell compression, hydrogen pressure, and (–) electrode architecture are investigated. Increasing hydrogen pressure and depositing the (–) catalyst layer on the membrane instead of on the carbon-paper backing layers have a large positive impact on performance, enabling a limiting current density above 2 A cm -2 and a peak power density of 1.4 W cm -2. Maximummore » energy efficiency of 79% is achieved. In addition, the root cause of limiting-current behavior in this system is elucidated, where it is found that Br - reversibly adsorbs at the Pt (–) electrode for potentials exceeding a critical value, and the extent of Br - coverage is potential-dependent. This phenomenon limits maximum cell current density and must be addressed in system modeling and design. These findings are expected to lower system cost and enable higher efficiency.« less

Exploration of Al-Doped ZnO in Photovoltaic Thin Films

NASA Astrophysics Data System (ADS)

Ciccarino, Christopher; Sahiner, M. Alper

The electrical properties of Al doped ZnO-based thin films represent a potential advancement in the push for increasing solar cell efficiency. Doping with Aluminum will theoretically decrease resistivity of the film and therefore achieve this potential as a viable option in the P-N junction phase of photovoltaic cells. The n-type semi-conductive characteristics of the ZnO layer will theoretically be optimized with the addition of Aluminum carriers. In this study, Aluminum doping concentrations ranging from 1-3% by mass were produced, analyzed, and compared. Films were developed onto ITO coated glass using the Pulsed Laser Deposition technique. Target thickness was 250 nm and ellipsometry measurements showed uniformity and accuracy in this regard. Active dopant concentrations were determined using Hall Effect measurements. Efficiency measurements showed possible applications of this doped compound, with upwards of 7% efficiency measured, using a Keithley 2602 SourceMeter set-up. XRD scans showed highly crystalline structures, with effective Al intertwining of the hexagonal wurtzile ZnO molecular structure. This alone indicates a promising future of collaboration between these two materials.

Organic-Inorganic Hybrid Perovskite with Controlled Dopant Modification and Application in Photovoltaic Device.

PubMed

Zhao, Wangen; Yang, Dong; Liu, Shengzhong Frank

2017-07-01

Organic-inorganic hybrid perovskite as a kind of promising photovoltaic material is booming due to its low-cost, high defect tolerance, and easy fabrication, which result in the huge potential in industrial production. In the pursuit of high efficiency photovoltaic devices, high-quality absorbing layer is essential. Therefore, developing organic-inorganic hybrid perovskite thin films with good coverage, improved uniformity, and crystalline in a single pass deposition is of great concern in realizing good performance of perovskite thin-film solar cell. Here, it is found that the introduction of suitable amounts of LiI plays a dramatically positive role in enlarging the grain size and reducing the grain boundaries of absorbing layer. In addition, the carrier lifetime and built-in potential of the LiI doped perovskite device are observed to increase. Thus, it leads to about 15% gain in solar cell efficiency comparing to that without the LiI doping. Meanwhile, a hysteresis reduction is observed and 18.16% power conversion efficiency is achieved in LiI doped perovskite device, as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser deposition of resonant silicon nanoparticles on perovskite for photoluminescence enhancement

NASA Astrophysics Data System (ADS)

Tiguntseva, E. Y.; Zalogina, A. S.; Milichko, V. A.; Zuev, D. A.; Omelyanovich, M. M.; Ishteev, A.; Cerdan Pasaran, A.; Haroldson, R.; Makarov, S. V.; Zakhidov, A. A.

2017-11-01

Hybrid lead halide perovskite based optoelectronics is a promising area of modern technologies yielding excellent characteristics of light emitting diodes and lasers as well as high efficiencies of photovoltaic devices. However, the efficiency of perovskite based devices hold a potential of further improvement. Here we demonstrate high photoluminescence efficiency of perovskites thin films via deposition of resonant silicon nanoparticles on their surface. The deposited nanoparticles have a number of advances over their plasmonic counterparts, which were applied in previous studies. We show experimentally the increase of photoluminescence of perovskite film with the silicon nanoparticles by 150 % as compared to the film without the nanoparticles. The results are supported by numerical calculations. Our results pave the way to high throughput implementation of low loss resonant nanoparticles in order to create highly effective perovskite based optoelectronic devices.

High efficiency coherent optical memory with warm rubidium vapour

PubMed Central

Hosseini, M.; Sparkes, B.M.; Campbell, G.; Lam, P.K.; Buchler, B.C.

2011-01-01

By harnessing aspects of quantum mechanics, communication and information processing could be radically transformed. Promising forms of quantum information technology include optical quantum cryptographic systems and computing using photons for quantum logic operations. As with current information processing systems, some form of memory will be required. Quantum repeaters, which are required for long distance quantum key distribution, require quantum optical memory as do deterministic logic gates for optical quantum computing. Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications. We also show storage and recall of up to 20 pulses from our system. These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory. PMID:21285952

High efficiency coherent optical memory with warm rubidium vapour.

PubMed

Hosseini, M; Sparkes, B M; Campbell, G; Lam, P K; Buchler, B C

2011-02-01

By harnessing aspects of quantum mechanics, communication and information processing could be radically transformed. Promising forms of quantum information technology include optical quantum cryptographic systems and computing using photons for quantum logic operations. As with current information processing systems, some form of memory will be required. Quantum repeaters, which are required for long distance quantum key distribution, require quantum optical memory as do deterministic logic gates for optical quantum computing. Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications. We also show storage and recall of up to 20 pulses from our system. These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory.

Efficient and safe gene delivery to human corneal endothelium using magnetic nanoparticles.

PubMed

Czugala, Marta; Mykhaylyk, Olga; Böhler, Philip; Onderka, Jasmine; Stork, Björn; Wesselborg, Sebastian; Kruse, Friedrich E; Plank, Christian; Singer, Bernhard B; Fuchsluger, Thomas A

2016-07-01

To develop a safe and efficient method for targeted, anti-apoptotic gene therapy of corneal endothelial cells (CECs). Magnetofection (MF), a combination of lipofection with magnetic nanoparticles (MNPs; PEI-Mag2, SO-Mag5, PalD1-Mag1), was tested in human CECs and in explanted human corneas. Effects on cell viability and function were investigated. Immunocompatibility was assessed in human peripheral blood mononuclear cells. Silica iron-oxide MNPs (SO-Mag5) combined with X-tremeGENE-HP achieved high transfection efficiency in human CECs and explanted human corneas, without altering cell viability or function. Magnetofection caused no immunomodulatory effects in human peripheral blood mononuclear cells. Magnetofection with anti-apoptotic P35 gene effectively blocked apoptosis in CECs. Magnetofection is a promising tool for gene therapy of corneal endothelial cells with potential for targeted on-site delivery.

A new method to evaluate the biocontrol potential of single spore isolates of fungal entomopathogens

PubMed Central

Posada, Francisco J.; Vega, Fernando E.

2005-01-01

Fifty Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) strains isolated from the coffee berry borer were used to develop a novel screening method aimed at selecting strains with the highest biocontrol potential. The screening method is based on percent insect mortality, average survival time, mortality distribution, percent spore germination, fungal life cycle duration, and spore production on the insect. Based on these parameters, only 11 strains merited further study. The use of a sound scientific protocol for the selection of promising fungal entomopathogens should lead to more efficient use of time, labor, and financial resources in biological control programs. PMID:17119619

Universal Effectiveness of Inducing Magnetic Moments in Graphene by Amino-Type sp3-Defects

PubMed Central

Wu, Liting; Gao, Shengqing; Li, Ming; Wen, Jianfeng; Li, Xinyu; Liu, Fuchi

2018-01-01

Inducing magnetic moments in graphene is very important for its potential application in spintronics. Introducing sp3-defects on the graphene basal plane is deemed as the most promising approach to produce magnetic graphene. However, its universal validity has not been very well verified experimentally. By functionalization of approximately pure amino groups on graphene basal plane, a spin-generalization efficiency of ~1 μB/100 NH2 was obtained for the first time, thus providing substantial evidence for the validity of inducing magnetic moments by sp3-defects. As well, amino groups provide another potential sp3-type candidate to prepare magnetic graphene. PMID:29673185

Conformation-Directed Formation of Self-Healing Diblock Copolypeptide Hydrogels via Polyion Complexation.

PubMed

Sun, Yintao; Wollenberg, Alexander L; O'Shea, Timothy Mark; Cui, Yanxiang; Zhou, Z Hong; Sofroniew, Michael V; Deming, Timothy J

2017-10-25

Synthetic diblock copolypeptides were designed to incorporate oppositely charged ionic segments that form β-sheet-structured hydrogel assemblies via polyion complexation when mixed in aqueous media. The observed chain conformation directed assembly was found to be required for efficient hydrogel formation and provided distinct and useful properties to these hydrogels, including self-healing after deformation, microporous architecture, and stability against dilution in aqueous media. While many promising self-assembled materials have been prepared using disordered or liquid coacervate polyion complex (PIC) assemblies, the use of ordered chain conformations in PIC assemblies to direct formation of new supramolecular morphologies is unprecedented. The promising attributes and unique features of the β-sheet-structured PIC hydrogels described here highlight the potential of harnessing conformational order derived from PIC assembly to create new supramolecular materials.

Advanced Plasma Propulsion for Human Missions to Jupiter

NASA Technical Reports Server (NTRS)

Donahue, Benjamin B.; Pearson, J. Boise

1999-01-01

This paper will briefly identify a promising fusion plasma power source, which when coupled with a promising electric thruster technology would provide for an efficient interplanetary transfer craft suitable to a 4 year round trip mission to the Jovian system. An advanced, nearly radiation free Inertial Electrostatic Confinement scheme for containing fusion plasma was judged as offering potential for delivering the performance and operational benefits needed for such high energy human expedition missions, without requiring heavy superconducting magnets for containment of the fusion plasma. Once the Jovian transfer stage has matched the heliocentric velocity of Jupiter, the energy requirements for excursions to its outer satellites (Callisto, Ganymede and Europa) by smaller excursion craft are not prohibitive. The overall propulsion, power and thruster system is briefly described and a preliminary vehicle mass statement is presented.

Energetic and environmental assessment of thermochemical and biochemical ways for producing energy from agricultural solid residues: Coffee Cut-Stems case.

PubMed

García, Carlos A; Peña, Álvaro; Betancourt, Ramiro; Cardona, Carlos A

2018-06-15

Forest residues are an important source of biomass. Among these, Coffee Cut-Stems (CCS) are an abundant wood waste in Colombia obtained from coffee crops renovation. However, only low quantities of these residues are used directly in combustion processes for heating and cooking in coffee farms where their energy efficiency is very low. In the present work, an energy and environmental assessment of two bioenergy production processes (ethanol fermentation and gasification) using CCS as raw material was performed. Biomass gasification seems to be the most promising thermochemical method for bioenergy production whereas, ethanol fermentation is a widely studied biochemical method to produce biofuels. Experimental runs of the CCS gasification were carried out and the synthesis gas composition was monitored. Prior to the fermentation process, a treatment of the CCS is required from which sugar content was determined and then, in the fermentation process, the ethanol yield was calculated. Both processes were simulated in order to obtain the mass and energy balance that are used to assess the energy efficiency and the potential environmental impact (PEI). Moderate high energy efficiency and low environmental impacts were obtained from the CCS gasification. In contrast, high environmental impacts in different categories and low energy efficiencies were calculated from the ethanolic fermentation. Biomass gasification seems to be the most promising technology for the use of Coffee Cut-Stems with high energy yields and low environmental issues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Review of solar fuel-producing quantum conversion processes

NASA Technical Reports Server (NTRS)

Peterson, D. B.; Biddle, J. R.; Fujita, T.

1984-01-01

The status and potential of fuel-producing solar photochemical processes are discussed. Research focused on splitting water to produce dihydrogen and is at a relatively early stage of development. Current emphasis is primarily directed toward understanding the basic chemistry underlying such quantum conversion processes. Theoretical analyses by various investigators predict a limiting thermodynamic efficiency of 31% for devices with a single photosystem operating with unfocused sunlight at 300 K. When non-idealities are included, it appears unlikely that actual devices will have efficiencies greater than 12 to 15%. Observed efficiencies are well below theoretical limits. Cyclic homogeneous photochemical processes for splitting water have efficiencies considerably less than 1%. Efficiency can be significantly increased by addition of a sacrificial reagent; however, such systems are no longer cyclic and it is doubtful that they would be economical on a commercial scale. The observed efficiencies for photoelectrochemical processes are also low but such systems appear more promising than homogeneous photochemical systems. Operating and systems options, including operation at elevated temperature and hybrid and coupled quantum-thermal conversion processes, are also considered.

Benefits of VTOL aircraft in offshore petroleum logistics support

NASA Technical Reports Server (NTRS)

Wilcox, D. E.; Shovlin, M. D.

1975-01-01

The mission suitability and potential economic benefits of advanced VTOL aircraft were investigated for logistics support of petroleum operations in the North Sea and the Gulf of Mexico. Concepts such as the tilt rotor and lift/cruise fan are promising for future operations beyond 150 miles offshore, where their high cruise efficiency provides savings in trip time, fuel consumption, and capital investment. Depending upon mission requirements, the aircraft operating costs are reduced by as much as 20 percent to 50 percent from those of current helicopters.

A theoretical/experimental program to develop active optical pollution sensors, part 2

NASA Technical Reports Server (NTRS)

Poultney, S. K.

1975-01-01

Progress is reported on experimental investigations of Lidar and the application of Lidar to environmental and atmospheric science. Specifically the following programs are considered: calibration and application of the LaRC 48-inch Lidar; efficient and certain detection of SO2 and other gases in the calibration tank using the Raman Stack Monitor Lidar; the potential of Lidar remote sensing from the space shuttle; and the planning and mounting of efforts to realize the promise of backscatter differential absorption Lidar.

A new prospect in cancer therapy: targeting cancer stem cells to eradicate cancer.

PubMed

Chen, Li-Sha; Wang, An-Xin; Dong, Bing; Pu, Ke-Feng; Yuan, Li-Hua; Zhu, Yi-Min

2012-12-01

According to the cancer stem cell theory, cancers can be initiated by cancer stem cells. This makes cancer stem cells prime targets for therapeutic intervention. Eradicating cancer stem cells by efficient targeting agents may have the potential to cure cancer. In this review, we summarize recent breakthroughs that have improved our understanding of cancer stem cells, and we discuss the therapeutic strategy of targeting cancer stem cells, a promising future direction for cancer stem cell research.

Bio-inspired evaporation through plasmonic film of nanoparticles at the air-water interface.

PubMed

Wang, Zhenhui; Liu, Yanming; Tao, Peng; Shen, Qingchen; Yi, Nan; Zhang, Fangyu; Liu, Quanlong; Song, Chengyi; Zhang, Di; Shang, Wen; Deng, Tao

2014-08-27

Plasmonic gold nanoparticles self-assembled at the air-water interface to produce an evaporative surface with local control inspired by skins and plant leaves. Fast and efficient evaporation is realized due to the instant and localized plasmonic heating at the evaporative surface. The bio-inspired evaporation process provides an alternative promising approach for evaporation, and has potential applications in sterilization, distillation, and heat transfer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of Triazole Derivatives of Levoglucosenone As Promising Anticancer Agents: Effective Exploration of the Chemical Space through retro-aza-Michael//aza-Michael Isomerizations.

PubMed

Tsai, Yi-Hsuan; Borini Etichetti, Carla M; Di Benedetto, Carolina; Girardini, Javier E; Martins, Felipe Terra; Spanevello, Rolando A; Suárez, Alejandra G; Sarotti, Ariel M

2018-04-06

The design and synthesis of biomass-derived triazoles and the in vitro evaluation as potential anticancer agents are described. The discovery of base-catalyzed retro-aza-Michael//aza-Michael isomerizations allowed the exploration of the chemical space by affording novel types of triazoles, difficult to obtain otherwise. Following this strategy, 2,4-disubstituted 1,2,3-triazoles could be efficiently obtained from the corresponding 1,4-disubstituted analogues.

In-house coordination project for organ and tissue procurement: social responsibility and promising results.

PubMed

Silva, Vanessa Silva E; Moura, Luciana Carvalho; Martins, Luciana Ribeiro; Santos, Roberta Cristina Cardoso Dos; Schirmer, Janine; Roza, Bartira de Aguiar

2016-01-01

to report the results of evaluation regarding changes in the number of potential donor referrals, actual donors, and conversion rates after the implementation of an in-house organ and tissue donation for transplantation coordination project. epidemiological study, both retrospective and transversal, was performed with organ donation data from the Secretariat of Health for the State and the in-house organ donation coordination project of a beneficent hospital. The data was compared using nonparametric statistical Mann-Whitney test, and the Student's t-test, considering a significance level of 5% (p <0.05). there were statistically significant differences (p < 0.05), before and after the implementation of the project on the number of potential donor notification/month (3.05 - 4.7 ), number of actual donor/month (0.78 to 1.60) and rate of conversion ( 24.7 to 34.8 %). The hospitals 1, 2, 7 and 8 had significant results in potential donor, actual donor or conversion rate. the presence of an in-house coordinator is promising and beneficial, the specialist is important to change the indicators of efficiency, which consequently reduces the waiting lists for organ transplants.

In-house coordination project for organ and tissue procurement: social responsibility and promising results 1

PubMed Central

Silva, Vanessa Silva e; Moura, Luciana Carvalho; Martins, Luciana Ribeiro; dos Santos, Roberta Cristina Cardoso; Schirmer, Janine; Roza, Bartira de Aguiar

2016-01-01

Abstract Objectives: to report the results of evaluation regarding changes in the number of potential donor referrals, actual donors, and conversion rates after the implementation of an in-house organ and tissue donation for transplantation coordination project. Methods: epidemiological study, both retrospective and transversal, was performed with organ donation data from the Secretariat of Health for the State and the in-house organ donation coordination project of a beneficent hospital. The data was compared using nonparametric statistical Mann-Whitney test, and the Student's t-test, considering a significance level of 5% (p <0.05). Results: there were statistically significant differences (p < 0.05), before and after the implementation of the project on the number of potential donor notification/month (3.05 - 4.7 ), number of actual donor/month (0.78 to 1.60) and rate of conversion ( 24.7 to 34.8 %). The hospitals 1, 2, 7 and 8 had significant results in potential donor, actual donor or conversion rate. Conclusion: the presence of an in-house coordinator is promising and beneficial, the specialist is important to change the indicators of efficiency, which consequently reduces the waiting lists for organ transplants. PMID:27463111

Solar upconversion with plasmon-enhanced bimolecular complexes

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

Dionne, Jennifer

2017-04-14

Upconversion of sub-bandgap photons is a promising approach to exceed the Shockley-Queisser limit in solar technologies. However, due to the low quantum efficiencies and narrow absorption bandwidths of upconverters, existing systems have only led to fractional percent improvements in photovoltaic devices (~0.01%). In this project, we aimed to develop an efficient upconverting material that could improve cell efficiencies by at least one absolute percent. To achieve this goal, we first used thermodynamic calculations to determine cell efficiencies with realistic upconverting materials. Then, we designed, synthesized, and characterized nanoantennas that promise >100x enhancement in both the upconverter absorption cross-section and emissivemore » radiative rate. Concurrently, we optimized the upconverer by designing new ionic and molecular complexes that promise efficient solid-state upconversion. Lastly, with Bosch, we simulated record-efficiency semi-transparent cells that will allow for ready incorporation of our upconverting materials. While we were not successful in designing record efficiency upconverters during our three years of funding, we gained significant insight into the existing limitations of upconverters and how to best address these challenges. Ongoing work is aimed at addressing these limitations, to make upconversion a cost-competitive solar technology in future years.« less

Engineering Yarrowia lipolytica as a platform for synthesis of drop-in transportation fuels and oleochemicals

PubMed Central

Xu, Peng; Qiao, Kangjian; Ahn, Woo Suk; Stephanopoulos, Gregory

2016-01-01

Harnessing lipogenic pathways and rewiring acyl-CoA and acyl-ACP (acyl carrier protein) metabolism in Yarrowia lipolytica hold great potential for cost-efficient production of diesel, gasoline-like fuels, and oleochemicals. Here we assessed various pathway engineering strategies in Y. lipolytica toward developing a yeast biorefinery platform for sustainable production of fuel-like molecules and oleochemicals. Specifically, acyl-CoA/acyl-ACP processing enzymes were targeted to the cytoplasm, peroxisome, or endoplasmic reticulum to generate fatty acid ethyl esters and fatty alkanes with tailored chain length. Activation of endogenous free fatty acids and the subsequent reduction of fatty acyl-CoAs enabled the efficient synthesis of fatty alcohols. Engineering a hybrid fatty acid synthase shifted the free fatty acids to a medium chain-length scale. Manipulation of alternative cytosolic acetyl-CoA pathways partially decoupled lipogenesis from nitrogen starvation and unleashed the lipogenic potential of Y. lipolytica. Taken together, the strategies reported here represent promising steps to develop a yeast biorefinery platform that potentially upgrades low-value carbons to high-value fuels and oleochemicals in a sustainable and environmentally friendly manner. PMID:27621436

High-Performance Solid-State Thermionic Energy Conversion Based on 2D van der Waals Heterostructures: A First-Principles Study.

PubMed

Wang, Xiaoming; Zebarjadi, Mona; Esfarjani, Keivan

2018-06-18

Two-dimensional (2D) van der Waals heterostructures (vdWHs) have shown multiple functionalities with great potential in electronics and photovoltaics. Here, we show their potential for solid-state thermionic energy conversion and demonstrate a designing strategy towards high-performance devices. We propose two promising thermionic devices, namely, the p-type Pt-G-WSe 2 -G-Pt and n-type Sc-WSe 2 -MoSe 2 -WSe 2 -Sc. We characterize the thermionic energy conversion performance of the latter using first-principles GW calculations combined with real space Green's function (GF) formalism. The optimal barrier height and high thermal resistance lead to an excellent performance. The proposed device is found to have a room temperature equivalent figure of merit of 1.2 which increases to 3 above 600 K. A high performance with cooling efficiency over 30% of the Carnot efficiency above 450 K is achieved. Our designing and characterization method can be used to pursue other potential thermionic devices based on vdWHs.

Carrier separation and transport in perovskite solar cells studied by nanometre-scale profiling of electrical potential

PubMed Central

Jiang, Chun-Sheng; Yang, Mengjin; Zhou, Yuanyuan; To, Bobby; Nanayakkara, Sanjini U.; Luther, Joseph M.; Zhou, Weilie; Berry, Joseph J.; van de Lagemaat, Jao; Padture, Nitin P.; Zhu, Kai; Al-Jassim, Mowafak M.

2015-01-01

Organometal–halide perovskite solar cells have greatly improved in just a few years to a power conversion efficiency exceeding 20%. This technology shows unprecedented promise for terawatt-scale deployment of solar energy because of its low-cost, solution-based processing and earth-abundant materials. We have studied charge separation and transport in perovskite solar cells—which are the fundamental mechanisms of device operation and critical factors for power output—by determining the junction structure across the device using the nanoelectrical characterization technique of Kelvin probe force microscopy. The distribution of electrical potential across both planar and porous devices demonstrates p–n junction structure at the TiO2/perovskite interfaces and minority-carrier diffusion/drift operation of the devices, rather than the operation mechanism of either an excitonic cell or a p-i-n structure. Combining the potential profiling results with solar cell performance parameters measured on optimized and thickened devices, we find that carrier mobility is a main factor that needs to be improved for further gains in efficiency of the perovskite solar cells. PMID:26411597

Carrier Separation and Transport in Perovskite Solar Cells Studied by Nanometre-Scale Profiling of Electrical Potential

DOE PAGES

Jiang, Chun-Sheng; Yang, Mengjin; Zhou, Yuanyuan; ...

2015-09-28

Organometal–halide perovskite solar cells have greatly improved in just a few years to a power conversion efficiency exceeding 20%. This technology shows unprecedented promise for terawatt-scale deployment of solar energy because of its low-cost, solution-based processing and earth-abundant materials. We have studied charge separation and transport in perovskite solar cells—which are the fundamental mechanisms of device operation and critical factors for power output—by determining the junction structure across the device using the nanoelectrical characterization technique of Kelvin probe force microscopy. Moreover, the distribution of electrical potential across both planar and porous devices demonstrates p–n junction structure at the TiO2/perovskite interfacesmore » and minority-carrier diffusion/drift operation of the devices, rather than the operation mechanism of either an excitonic cell or a p-i-n structure. When we combined the potential profiling results with solar cell performance parameters measured on optimized and thickened devices, we find that carrier mobility is a main factor that needs to be improved for further gains in efficiency of the perovskite solar cells.« less

On the potential for BECCS efficiency improvement through heat recovery from both post-combustion and oxy-combustion facilities.

PubMed

Dowell, N Mac; Fajardy, M

2016-10-20

In order to mitigate climate change to no more than 2 °C, it is well understood that it will be necessary to directly remove significant quantities of CO 2 , with bioenergy CCS (BECCS) regarded as a promising technology. However, BECCS will likely be more costly and less efficient at power generation than conventional CCS. Thus, approaches to improve BECCS performance and reduce costs are of importance to facilitate the deployment of this key technology. In this study, the impact of biomass co-firing rate and biomass moisture content on BECCS efficiency with both post- and oxy-combustion CO 2 capture technologies was evaluated. It was found that post-combustion capture BECCS (PCC-BECCS) facilities will be appreciably less efficient than oxy-combustion capture BECCS (OCC-BECCS) facilities. Consequently, PCC-BECCS have the potential to be more carbon negative than OCC-BECCS per unit electricity generated. It was further observed that the biomass moisture content plays an important role in determining the BECCS facilities' efficiency. This will in turn affect the enthalpic content of the BECCS plant exhaust and implies that exhaust gas heat recovery may be an attractive option at higher rates of co-firing. It was found that there is the potential for the recovery of approximately 2.5 GJ heat per t CO 2 at a temperature of 100 °C from both PCC-BECCS and OCC-BECCS. On- and off-site applications for this recovered heat are discussed, considering boiler feedwater pre-heating, solvent regeneration and district heating cases.

Toward a III-V Multijunction Space Cell Technology on Si

NASA Technical Reports Server (NTRS)

Ringel, S. A.; Lueck, M. R.; Andre, C. L.; Fitzgerald, E. A.; Wilt, D. M.; Scheiman, D.

2007-01-01

High efficiency compound semiconductor solar cells grown on Si substrates are of growing interest in the photovoltaics community for both terrestrial and space applications. As a potential substrate for III-V compound photovoltaics, Si has many advantages over traditional Ge and GaAs substrates that include higher thermal conductivity, lower weight, lower material costs, and the potential to leverage the extensive manufacturing base of the Si industry. Such a technology that would retain high solar conversion efficiency at reduced weight and cost would result in space solar cells that simultaneously possess high specific power (W/kg) and high power density (W/m2). For terrestrial solar cells this would result in high efficiency III-V concentrators with improved thermal conductivity, reduced cost, and via the use of SiGe graded interlayers as active component layers the possibility of integrating low bandgap sub-cells that could provide for extremely high conversion efficiency.1 In addition to photovoltaics, there has been an historical interest in III-V/Si integration to provide optical interconnects in Si electronics, which has become of even greater relevance recently due to impending bottlenecks in CMOS based circuitry. As a result, numerous strategies to integrate GaAs with Si have been explored with the primary issue being the approx.4% lattice mismatch between GaAs and Si. Among these efforts, relaxed, compositionally-graded SiGe buffer layers where the substrate lattice constant is effectively tuned from Si to that of Ge so that a close lattice match to subsequent GaAs overlayers have shown great promise. With this approach, threading dislocation densities (TDDs) of approx.1 x 10(exp 6)/sq cm have been uniformly achieved in relaxed Ge layers on Si,5 leading to GaAs on Si with minority carrier lifetimes greater than 10 ns,6 GaAs single junction solar cells on Si with efficiencies greater than 18%,7 InGaAs CW laser diodes on Si,8 and room temperature GaInP red laser diodes on Si.9 Here we report on the first high performance dual junction GaInP/GaAs solar cells grown on Si using this promising SiGe engineered substrate approach.

Effective flocculation of Chlorella vulgaris using chitosan with zeta potential measurement

NASA Astrophysics Data System (ADS)

Low, Y. J.; Lau, S. W.

2017-06-01

Microalgae are considered as one promising source of third-generation biofuels due to their fast growth rates, potentially higher yield rates and wide ranges of growth conditions. However, the extremely low biomass concentration in microalgae cultures presents a great challenge to the harvesting of microalgae because a large volume of water needs to be removed to obtain dry microalgal cells for the subsequent oil extraction process. In this study, the fresh water microalgae Chlorella vulgaris (C. vulgaris) was effectively harvested using both low molecular weight (MW) and high MW chitosan flocculants. The flocculation efficiency was evaluated by physical appearance, supernatant absorbance, zeta potential and solids content after centrifugal dewatering. High flocculation efficiency of 98.0-99.0% was achieved at the optimal dosage of 30-40 mg/g with formation of large microalgae flocs. This study suggests that the polymer bridging mechanism was governing the flocculation behaviour of C. vulgaris using high MW chitosan. Besides, charge patch neutralisation mechanism prevailed at low MW chitosan where lower dosage was sufficient to reach near-zero zeta potential compared with the high MW chitosan. The amount of chitosan polymer present in the culture may also affect the mechanism of flocculation.

Nanobubbles: a promising efficient tool for therapeutic delivery.

PubMed

Cavalli, Roberta; Soster, Marco; Argenziano, Monica

2016-01-01

In recent decades ultrasound-guided delivery of drugs loaded on nanocarriers has been the focus of increasing attention to improve therapeutic treatments. Ultrasound has often been used in combination with microbubbles, micron-sized spherical gas-filled structures stabilized by a shell, to amplify the biophysical effects of the ultrasonic field. Nanometer size bubbles are defined nanobubbles. They were designed to obtain more efficient drug delivery systems. Indeed, their small sizes allow extravasation from blood vessels into surrounding tissues and ultrasound-targeted site-specific release with minimal invasiveness. Additionally, nanobubbles might be endowed with improved stability and longer residence time in systemic circulation. This review will describe the physico-chemical properties of nanobubbles, the formulation parameters and the drug loading approaches, besides potential applications as a therapeutic tool.

Efficient Hydrogen Storage and Production Using a Catalyst with an Imidazoline-Based, Proton-Responsive Ligand.

PubMed

Wang, Lin; Onishi, Naoya; Murata, Kazuhisa; Hirose, Takuji; Muckerman, James T; Fujita, Etsuko; Himeda, Yuichiro

2017-03-22

A series of new imidazoline-based iridium complexes has been developed for hydrogenation of CO 2 and dehydrogenation of formic acid. One of the proton-responsive complexes bearing two -OH groups at ortho and para positions on a coordinating pyridine ring (3 b) can catalyze efficiently the chemical fixation of CO 2 and release H 2 under mild conditions in aqueous media without using organic additives/solvents. Notably, hydrogenation of CO 2 can be efficiently carried out under CO 2 and H 2 at atmospheric pressure in basic water by 3 b, achieving a turnover frequency of 106 h -1 and a turnover number of 7280 at 25 °C, which are higher than ever reported. Moreover, highly efficient CO-free hydrogen production from formic acid in aqueous solution employing the same catalyst under mild conditions has been achieved, thus providing a promising potential H 2 -storage system in water. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

2-Aminoimidazole facilitates efficient gene delivery in a low molecular weight poly(amidoamine) dendrimer.

PubMed

Wang, Jing; Hu, Xuefeng; Wang, Dongli; Xie, Cao; Lu, Weiyue; Song, Jie; Wang, Ruifeng; Gao, Chunli; Liu, Min

2018-06-20

Functional groups have shown great potential in gene delivery. However, a number of the reported functional groups can only overcome one certain physiological barrier, resulting in limited transfection efficiencies. Based on the structure-activity relationships of both imidazolyl and guanidyl, we designed a novel multifunctional group, 2-aminoimidazole (AM), for gene delivery. On modifying with the AM group, the transfection efficiency of low molecular weight poly(amidoamine) (G2) was 200 times greater than the parent dendrimer in vitro. In contrast, the transfection efficiency of G2 showed a decreasing trend when it was grafted with imidazole. Assays revealed that the AM group played multiple roles in gene delivery, including condensing DNA into monodisperse nanoparticles of 80-90 nm in diameter, achieving nearly ten times higher cellular-uptake efficacy, and enhancing the abilities of endosome/lysosome escape and nuclear localization. What's more, AM showed low toxicity. These results demonstrate that the AM group could be a promising tool in non-viral gene delivery.

Efficient hydrogen storage and production using a catalyst with an imidazoline-based, proton-responsive ligand

DOE PAGES

Wang, Lin; Onishi, Naoya; Murata, Kazuhisa; ...

2016-12-28

A series of new imidazoline-based iridium complexes has been developed for hydrogenation of CO 2 and dehydrogenation of formic acid. One of the proton-responsive complexes bearing two –OH groups at ortho and para positions on a coordinating pyridine ring (3 b) can catalyze efficiently the chemical fixation of CO 2 and release H 2 under mild conditions in aqueous media without using organic additives/solvents. Notably, hydrogenation of CO 2 can be efficiently carried out under CO 2 and H 2 at atmospheric pressure in basic water by 3 b, achieving a turnover frequency of 106 h –1 and a turnovermore » number of 7280 at 25 °C, which are higher than ever reported. Furthermore, highly efficient CO-free hydrogen production from formic acid in aqueous solution employing the same catalyst under mild conditions has been achieved, thus providing a promising potential H 2-storage system in water.« less

Solar energy conversion with photon-enhanced thermionic emission

NASA Astrophysics Data System (ADS)

Kribus, Abraham; Segev, Gideon

2016-07-01

Photon-enhanced thermionic emission (PETE) converts sunlight to electricity with the combined photonic and thermal excitation of charge carriers in a semiconductor, leading to electron emission over a vacuum gap. Theoretical analyses predict conversion efficiency that can match, or even exceed, the efficiency of traditional solar thermal and photovoltaic converters. Several materials have been examined as candidates for radiation absorbers and electron emitters, with no conclusion yet on the best set of materials to achieve high efficiency. Analyses have shown the complexity of the energy conversion and transport processes, and the significance of several loss mechanisms, requiring careful control of material properties and optimization of the device structure. Here we survey current research on PETE modeling, materials, and device configurations, outline the advances made, and stress the open issues and future research needed. Based on the substantial progress already made in this young topic, and the potential of high conversion efficiency based on theoretical performance limits, continued research in this direction is very promising and may yield a competitive technology for solar electricity generation.

Enhancement of the reduction efficiency of soluble starch for platinum nanoparticles synthesis.

PubMed

Tongsakul, Duangta; Wongravee, Kanet; Thammacharoen, Chuchaat; Ekgasit, Sanong

2012-08-01

In this work, the efficiency of soluble starch as a reducing and a stabilizing agent in the synthesis of platinum nanoparticles under acidic-alkaline treatment is systematically studied. The degraded intermediates with reducing potential (i.e., small molecules containing aldehyde and α-hydroxy ketone moieties) are concomitantly generated when the alkaline concentration is greater than 0.025 M. The in situ generated species could completely reduce platinum ions (20 mM) and sufficiently stabilize the obtained platinum nanoparticles (5 mM) of uniform particle size (2-4 nm). The reduction is efficient and rapid as a complete conversion is achieved within 5 min. In a stronger alkaline condition, the platinum nanoparticles tend to aggregate and form a bigger domain because extensive degradation generates small starch fragments with less stabilization efficiency. This observation suggests that starch is a promising green material which could be chemically treated and transformed to a powerful reducing agent and stabilizer for the synthesis of metal nanoparticles. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simultaneous Formation of Artificial SEI Film and 3D Host for Stable Metallic Sodium Anodes.

PubMed

Zhang, Di; Li, Bin; Wang, Shuai; Yang, Shubin

2017-11-22

Metallic sodium is a promising anode for sodium-based batteries, owing to its high theoretical capacity (1165 mAh g -1 ) and low potential (-2.714 V vs standard hydrogen electrode). However, the growth of sodium dendrites and the infinite volume change of metallic sodium during sodium striping/plating result in a low Coulombic efficiency and poor cycling stability, generating a safety hazard of sodium-based batteries. Here, an efficient approach was proposed to simultaneously generate an artificial SEI film and 3D host for metallic sodium based on a conversion reaction (CR) between sodium and MoS 2 (4Na + MoS 2 = 2Na 2 S + Mo) at room temperature. In the resultant sodium-MoS 2 hybrid after the conversion reaction (Na-MoS 2 (CR)), the production Na 2 S is homogeneously dispersed on the surface of metallic sodium, which can act as an artificial SEI film, efficiently preventing the growth of sodium dendrites; the residual MoS 2 nanosheets can construct a 3D host to confine metallic sodium, accommodating largely the volume change of sodium. Consequently, the Na-MoS 2 (CR) hybrid exhibits very low overpotential of 25 mV and a very long cycle stability more than 1000 cycles. This novel strategy is promising to promote the development of metal (lithium, sodium, zinc)-based electrodes.

Genetic engineering of human embryonic stem cells with lentiviral vectors.

PubMed

Xiong, Chen; Tang, Dong-Qi; Xie, Chang-Qing; Zhang, Li; Xu, Ke-Feng; Thompson, Winston E; Chou, Wayne; Gibbons, Gary H; Chang, Lung-Ji; Yang, Li-Jun; Chen, Yuqing E

2005-08-01

Human embryonic stem (hES) cells present a valuable source of cells with a vast therapeutic potential. However, the low efficiency of directed differentiation of hES cells remains a major obstacle in their uses for regenerative medicine. While differentiation may be controlled by the genetic manipulation, effective and efficient gene transfer into hES cells has been an elusive goal. Here, we show stable and efficient genetic manipulations of hES cells using lentiviral vectors. This method resulted in the establishment of stable gene expression without loss of pluripotency in hES cells. In addition, lentiviral vectors were effective in conveying the expression of an U6 promoter-driven small interfering RNA (siRNA), which was effective in silencing its specific target. Taken together, our results suggest that lentiviral gene delivery holds great promise for hES cell research and application.

Improvement of efficiency in graphene/gallium nitride nanowire on Silicon photoelectrode for overall water splitting

NASA Astrophysics Data System (ADS)

Bae, Hyojung; Rho, Hokyun; Min, Jung-Wook; Lee, Yong-Tak; Lee, Sang Hyun; Fujii, Katsushi; Lee, Hyo-Jong; Ha, Jun-Seok

2017-11-01

Gallium nitride (GaN) nanowires are one of the most promising photoelectrode materials due to their high stability in acidic and basic electrolytes, and tunable band edge potentials. In this study, GaN nanowire arrays (GaN NWs) were prepared by molecular beam epitaxy (MBE); their large surface area enhanced the solar to hydrogen conversion efficiency. More significantly, graphene was grown by chemical vapor deposition (CVD), which enhanced the electron transfer between NWs for water splitting and protected the GaN NW surface. Structural characterizations of the prepared composite were performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocurrent density of Gr/GaN NWs exhibited a two-fold increase over pristine GaN NWs and sustained water splitting up to 70 min. These improvements may accelerate possible applications for hydrogen generation with high solar to hydrogen conversion efficiency.

A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage.

PubMed

Zhao, Yu; Ding, Yu; Li, Yutao; Peng, Lele; Byon, Hye Ryung; Goodenough, John B; Yu, Guihua

2015-11-21

Electrical energy storage system such as secondary batteries is the principle power source for portable electronics, electric vehicles and stationary energy storage. As an emerging battery technology, Li-redox flow batteries inherit the advantageous features of modular design of conventional redox flow batteries and high voltage and energy efficiency of Li-ion batteries, showing great promise as efficient electrical energy storage system in transportation, commercial, and residential applications. The chemistry of lithium redox flow batteries with aqueous or non-aqueous electrolyte enables widened electrochemical potential window thus may provide much greater energy density and efficiency than conventional redox flow batteries based on proton chemistry. This Review summarizes the design rationale, fundamentals and characterization of Li-redox flow batteries from a chemistry and material perspective, with particular emphasis on the new chemistries and materials. The latest advances and associated challenges/opportunities are comprehensively discussed.

In situ prepared transparent polyaniline electrode and its application in bifacial dye-sensitized solar cells.

PubMed

Tai, Qidong; Chen, Bolei; Guo, Feng; Xu, Sheng; Hu, Hao; Sebo, Bobby; Zhao, Xing-Zhong

2011-05-24

Highly uniform and transparent polyaniline (PANI) electrodes that can be used as counter electrodes in dye-sensitized solar cells (DSSCs) were prepared by a facile in situ polymerization method. They were used to fabricate a novel bifacially active transparent DSSC, which showed conversion efficiencies of 6.54 and 4.26% corresponding to front- and rear-side illumination, respectively. Meanwhile, the efficiency of the same photoanode employing a Pt counter electrode was 6.69%. Compared to conventional Pt-based DSSCs, the design of the bifacial DSSC fabricated in this work would help to bring down the cost of energy production due to the lower cost of the materials and the higher power-generating efficiency of such devices for their capabilities of utilizing the light from both sides. These promising results highlight the potential application of PANI in cost-effective, transparent DSSCs.

Strategies to Maximize the Potential of Marine Biomaterials as a Platform for Cell Therapy

PubMed Central

Kim, Hyeongmin; Lee, Jaehwi

2016-01-01

Marine biopolymers have been explored as a promising cell therapy system for efficient cell delivery and tissue engineering. However, the marine biomaterial-based systems themselves have exhibited limited performance in terms of maintenance of cell viability and functions, promotion of cell proliferation and differentiation as well as cell delivery efficiency. Thus, numerous novel strategies have been devised to improve cell therapy outcomes. The strategies include optimization of physical and biochemical properties, provision of stimuli-responsive functions, and design of platforms for efficient cell delivery and tissue engineering. These approaches have demonstrated substantial improvement of therapeutic outcomes in a variety of research settings. In this review, therefore, research progress made with marine biomaterials as a platform for cell therapy is reported along with current research directions to further advance cell therapies as a tool to cure incurable diseases. PMID:26821034

Molecular Design of Benzodithiophene-Based Organic Photovoltaic Materials.

PubMed

Yao, Huifeng; Ye, Long; Zhang, Hao; Li, Sunsun; Zhang, Shaoqing; Hou, Jianhui

2016-06-22

Advances in the design and application of highly efficient conjugated polymers and small molecules over the past years have enabled the rapid progress in the development of organic photovoltaic (OPV) technology as a promising alternative to conventional solar cells. Among the numerous OPV materials, benzodithiophene (BDT)-based polymers and small molecules have come to the fore in achieving outstanding power conversion efficiency (PCE) and breaking 10% efficiency barrier in the single junction OPV devices. Remarkably, the OPV device featured by BDT-based polymer has recently demonstrated an impressive PCE of 11.21%, indicating the great potential of this class of materials in commercial photovoltaic applications. In this review, we offered an overview of the organic photovoltaic materials based on BDT from the aspects of backbones, functional groups, alkyl chains, and device performance, trying to provide a guideline about the structure-performance relationship. We believe more exciting BDT-based photovoltaic materials and devices will be developed in the near future.

Characterization of the powertrain components for a hybrid quadricycle

NASA Astrophysics Data System (ADS)

De Santis, M.; Agnelli, S.; Silvestri, L.; Di Ilio, G.; Giannini, O.

2016-06-01

This paper presents the experimental characterization of a prototyping hybrid electric quadricycle, which is equipped with two independently actuated hub (in-wheel) motors and powered by a 51 V 132 Ah LiFeYPO4 battery pack. Such a vehicle employs two hub motors located in the rear axles in order to independently drive/brake the rear wheels; such architecture allows to implement a torque vectoring system to improve the vehicle dynamics. Due to its actuation flexibility, energy efficiency and performance potentials, this architecture is one of the promising powertrain design for electric quadricycle. Experimental data obtained from measurements on the vehicle powertrain components going from the battery pack to the inverter and to the in-wheel motor were employed to generate the hub motor torque response and power efficiency maps in both driving and regenerative braking modes. Furthermore, the vehicle is equipped with a gasoline internal combustion engine as range extender whose efficiency was also characterized.

g-force induced giant efficiency of nanoparticles internalization into living cells

PubMed Central

Ocampo, Sandra M.; Rodriguez, Vanessa; de la Cueva, Leonor; Salas, Gorka; Carrascosa, Jose. L.; Josefa Rodríguez, María; García-Romero, Noemí; Luis, Jose; Cuñado, F.; Camarero, Julio; Miranda, Rodolfo; Belda-Iniesta, Cristobal; Ayuso-Sacido, Angel

2015-01-01

Nanotechnology plays an increasingly important role in the biomedical arena. Iron oxide nanoparticles (IONPs)-labelled cells is one of the most promising approaches for a fast and reliable evaluation of grafted cells in both preclinical studies and clinical trials. Current procedures to label living cells with IONPs are based on direct incubation or physical approaches based on magnetic or electrical fields, which always display very low cellular uptake efficiencies. Here we show that centrifugation-mediated internalization (CMI) promotes a high uptake of IONPs in glioblastoma tumour cells, just in a few minutes, and via clathrin-independent endocytosis pathway. CMI results in controllable cellular uptake efficiencies at least three orders of magnitude larger than current procedures. Similar trends are found in human mesenchymal stem cells, thereby demonstrating the general feasibility of the methodology, which is easily transferable to any laboratory with great potential for the development of improved biomedical applications. PMID:26477718

Efficient Near-Infrared-Transparent Perovskite Solar Cells Enabling Direct Comparison of 4-Terminal and Monolithic Perovskite/Silicon Tandem Cells

DOE PAGES

Werner, Jeremie; Barraud, Loris; Walter, Arnaud; ...

2016-07-30

Combining market-proven silicon solar cell technology with an efficient wide band gap top cell into a tandem device is an attractive approach to reduce the cost of photovoltaic systems. For this, perovskite solar cells are promising high-efficiency top cell candidates, but their typical device size (<0.2 cm 2), is still far from standard industrial sizes. Here, we present a 1 cm 2 near-infrared transparent perovskite solar cell with 14.5% steadystate efficiency, as compared to 16.4% on 0.25 cm 2. By mechanically stacking these cells with silicon heterojunction cells, we experimentally demonstrate a 4-terminal tandem measurement with a steady-state efficiency ofmore » 25.2%, with a 0.25 cm 2 top cell. The developed top cell processing methods enable the fabrication of a 20.5% efficient and 1.43 cm 2 large monolithic perovskite/silicon heterojunction tandem solar cell, featuring a rear-side textured bottom cell to increase its near-infrared spectral response. Finally, we compare both tandem configurations to identify efficiency-limiting factors and discuss the potential for further performance improvement.« less

Efficient Near-Infrared-Transparent Perovskite Solar Cells Enabling Direct Comparison of 4-Terminal and Monolithic Perovskite/Silicon Tandem Cells

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

Werner, Jeremie; Barraud, Loris; Walter, Arnaud

Combining market-proven silicon solar cell technology with an efficient wide band gap top cell into a tandem device is an attractive approach to reduce the cost of photovoltaic systems. For this, perovskite solar cells are promising high-efficiency top cell candidates, but their typical device size (<0.2 cm 2), is still far from standard industrial sizes. Here, we present a 1 cm 2 near-infrared transparent perovskite solar cell with 14.5% steadystate efficiency, as compared to 16.4% on 0.25 cm 2. By mechanically stacking these cells with silicon heterojunction cells, we experimentally demonstrate a 4-terminal tandem measurement with a steady-state efficiency ofmore » 25.2%, with a 0.25 cm 2 top cell. The developed top cell processing methods enable the fabrication of a 20.5% efficient and 1.43 cm 2 large monolithic perovskite/silicon heterojunction tandem solar cell, featuring a rear-side textured bottom cell to increase its near-infrared spectral response. Finally, we compare both tandem configurations to identify efficiency-limiting factors and discuss the potential for further performance improvement.« less

Does aquaculture add resilience to the global food system?

PubMed

Troell, Max; Naylor, Rosamond L; Metian, Marc; Beveridge, Malcolm; Tyedmers, Peter H; Folke, Carl; Arrow, Kenneth J; Barrett, Scott; Crépin, Anne-Sophie; Ehrlich, Paul R; Gren, Asa; Kautsky, Nils; Levin, Simon A; Nyborg, Karine; Österblom, Henrik; Polasky, Stephen; Scheffer, Marten; Walker, Brian H; Xepapadeas, Tasos; de Zeeuw, Aart

2014-09-16

Aquaculture is the fastest growing food sector and continues to expand alongside terrestrial crop and livestock production. Using portfolio theory as a conceptual framework, we explore how current interconnections between the aquaculture, crop, livestock, and fisheries sectors act as an impediment to, or an opportunity for, enhanced resilience in the global food system given increased resource scarcity and climate change. Aquaculture can potentially enhance resilience through improved resource use efficiencies and increased diversification of farmed species, locales of production, and feeding strategies. However, aquaculture's reliance on terrestrial crops and wild fish for feeds, its dependence on freshwater and land for culture sites, and its broad array of environmental impacts diminishes its ability to add resilience. Feeds for livestock and farmed fish that are fed rely largely on the same crops, although the fraction destined for aquaculture is presently small (∼4%). As demand for high-value fed aquaculture products grows, competition for these crops will also rise, as will the demand for wild fish as feed inputs. Many of these crops and forage fish are also consumed directly by humans and provide essential nutrition for low-income households. Their rising use in aquafeeds has the potential to increase price levels and volatility, worsening food insecurity among the most vulnerable populations. Although the diversification of global food production systems that includes aquaculture offers promise for enhanced resilience, such promise will not be realized if government policies fail to provide adequate incentives for resource efficiency, equity, and environmental protection.

Does aquaculture add resilience to the global food system?

PubMed Central

Troell, Max; Naylor, Rosamond L.; Metian, Marc; Beveridge, Malcolm; Tyedmers, Peter H.; Folke, Carl; Arrow, Kenneth J.; Barrett, Scott; Crépin, Anne-Sophie; Ehrlich, Paul R.; Gren, Åsa; Kautsky, Nils; Levin, Simon A.; Nyborg, Karine; Österblom, Henrik; Polasky, Stephen; Scheffer, Marten; Walker, Brian H.; Xepapadeas, Tasos; de Zeeuw, Aart

2014-01-01

Aquaculture is the fastest growing food sector and continues to expand alongside terrestrial crop and livestock production. Using portfolio theory as a conceptual framework, we explore how current interconnections between the aquaculture, crop, livestock, and fisheries sectors act as an impediment to, or an opportunity for, enhanced resilience in the global food system given increased resource scarcity and climate change. Aquaculture can potentially enhance resilience through improved resource use efficiencies and increased diversification of farmed species, locales of production, and feeding strategies. However, aquaculture’s reliance on terrestrial crops and wild fish for feeds, its dependence on freshwater and land for culture sites, and its broad array of environmental impacts diminishes its ability to add resilience. Feeds for livestock and farmed fish that are fed rely largely on the same crops, although the fraction destined for aquaculture is presently small (∼4%). As demand for high-value fed aquaculture products grows, competition for these crops will also rise, as will the demand for wild fish as feed inputs. Many of these crops and forage fish are also consumed directly by humans and provide essential nutrition for low-income households. Their rising use in aquafeeds has the potential to increase price levels and volatility, worsening food insecurity among the most vulnerable populations. Although the diversification of global food production systems that includes aquaculture offers promise for enhanced resilience, such promise will not be realized if government policies fail to provide adequate incentives for resource efficiency, equity, and environmental protection. PMID:25136111

Preparation of Deep Sea Fish Oil-Based Nanostructured Lipid Carriers with Enhanced Cellular Uptake.

PubMed

Zhu, Qiu-Yun; Guissi, Fida; Yang, Ru-Ya; Wang, Qian; Wang, Ke; Chen, Dan; Han, Zhi-Hao; Ma, Yi; Zhang, Min; Gu, Yue-Qing

2015-12-01

Nanostructured lipid carriers (NLC) are a promising pharmaceutical delivery system with mean diameter less than 200 nm which are dispersed in an aqueous phase containing emulsifier(s), to increase the water solubility, stability and bioavailability of oil compounds. Herein we prepared a promising NLC with glyceryl monostearate (GMS) as the solid lipid template and deep sea fish oil as the liquid lipid template using melted-ultrasonic method. Fish oil-NLC had a mean size of 84.7 ± 2.6 nm and a zeta potential that ranged from -17.87 mV to -32.91 mV. The nanoparticles exhibited good stability for four weeks with a high encapsulation efficiency of 87.5 ± 5.2%. Afterwards, confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) were used to investigate the contribution of Fish oil-NLC in enhancing fluorescein isothiocyanate (FITC) cellular uptake in comparison with free FITC. The results of this study indicated the possibility of this carrier to overcome the shortcomings of deep sea fish oil and to provide a novel bifunctional carrier with nutritional potential and drug delivery ability.

Overview and Highlights of WOLEDs and Organic Solar Cells: From Research to Applications

NASA Astrophysics Data System (ADS)

Chan, Maggie Mei-Yee; Tao, Chi-Hang; Yam, Vivian Wing-Wah

Solid-state organic devices are at the vanguard of new generation of electronic components owing to their promise to be easily manufactured onto flexible substrates that potentially reduce the mass production cost for large modules. With the great efforts on improving the power efficiency that meets the realistic requirements for commercial applications, white organic light-emitting devices (WOLEDs) and organic solar cells have attracted much attention over the past two decades and are targeted as the effective ways for reducing the energy consumption and developing renewable energy in the world. Because of their great potentials to generate tremendous savings in both cost and energy usage, WOLEDs are considered as new generations of solid-state lighting sources to replace the incandescent bulbs, while organic solar cells are the most promising candidates to complement the inorganic silicon solar cells for electricity generation. Here, we will provide a survey on the recent developments of WOLEDs and organic solar cells and their current status in these fields. Resistances and hampers to the widespread acceptances of these two areas of developments are also discussed.

Exploiting the 2-Amino-1,3,4-thiadiazole Scaffold To Inhibit Trypanosoma brucei Pteridine Reductase in Support of Early-Stage Drug Discovery

PubMed Central

2017-01-01

Pteridine reductase-1 (PTR1) is a promising drug target for the treatment of trypanosomiasis. We investigated the potential of a previously identified class of thiadiazole inhibitors of Leishmania major PTR1 for activity against Trypanosoma brucei (Tb). We solved crystal structures of several TbPTR1-inhibitor complexes to guide the structure-based design of new thiadiazole derivatives. Subsequent synthesis and enzyme- and cell-based assays confirm new, mid-micromolar inhibitors of TbPTR1 with low toxicity. In particular, compound 4m, a biphenyl-thiadiazole-2,5-diamine with IC50 = 16 μM, was able to potentiate the antitrypanosomal activity of the dihydrofolate reductase inhibitor methotrexate (MTX) with a 4.1-fold decrease of the EC50 value. In addition, the antiparasitic activity of the combination of 4m and MTX was reversed by addition of folic acid. By adopting an efficient hit discovery platform, we demonstrate, using the 2-amino-1,3,4-thiadiazole scaffold, how a promising tool for the development of anti-T. brucei agents can be obtained. PMID:28983525

Exploiting the 2-Amino-1,3,4-thiadiazole Scaffold To Inhibit Trypanosoma brucei Pteridine Reductase in Support of Early-Stage Drug Discovery.

PubMed

Linciano, Pasquale; Dawson, Alice; Pöhner, Ina; Costa, David M; Sá, Monica S; Cordeiro-da-Silva, Anabela; Luciani, Rosaria; Gul, Sheraz; Witt, Gesa; Ellinger, Bernhard; Kuzikov, Maria; Gribbon, Philip; Reinshagen, Jeanette; Wolf, Markus; Behrens, Birte; Hannaert, Véronique; Michels, Paul A M; Nerini, Erika; Pozzi, Cecilia; di Pisa, Flavio; Landi, Giacomo; Santarem, Nuno; Ferrari, Stefania; Saxena, Puneet; Lazzari, Sandra; Cannazza, Giuseppe; Freitas-Junior, Lucio H; Moraes, Carolina B; Pascoalino, Bruno S; Alcântara, Laura M; Bertolacini, Claudia P; Fontana, Vanessa; Wittig, Ulrike; Müller, Wolfgang; Wade, Rebecca C; Hunter, William N; Mangani, Stefano; Costantino, Luca; Costi, Maria P

2017-09-30

Pteridine reductase-1 (PTR1) is a promising drug target for the treatment of trypanosomiasis. We investigated the potential of a previously identified class of thiadiazole inhibitors of Leishmania major PTR1 for activity against Trypanosoma brucei ( Tb ). We solved crystal structures of several Tb PTR1-inhibitor complexes to guide the structure-based design of new thiadiazole derivatives. Subsequent synthesis and enzyme- and cell-based assays confirm new, mid-micromolar inhibitors of Tb PTR1 with low toxicity. In particular, compound 4m , a biphenyl-thiadiazole-2,5-diamine with IC 50 = 16 μM, was able to potentiate the antitrypanosomal activity of the dihydrofolate reductase inhibitor methotrexate (MTX) with a 4.1-fold decrease of the EC 50 value. In addition, the antiparasitic activity of the combination of 4m and MTX was reversed by addition of folic acid. By adopting an efficient hit discovery platform, we demonstrate, using the 2-amino-1,3,4-thiadiazole scaffold, how a promising tool for the development of anti- T. brucei agents can be obtained.

Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials

PubMed Central

Han, Tae-Hee; Choi, Mi-Ri; Jeon, Chan-Woo; Kim, Yun-Hi; Kwon, Soon-Ki; Lee, Tae-Woo

2016-01-01

Although solution processing of small-molecule organic light-emitting diodes (OLEDs) has been considered as a promising alternative to standard vacuum deposition requiring high material and processing cost, the devices have suffered from low luminous efficiency and difficulty of multilayer solution processing. Therefore, high efficiency should be achieved in simple-structured small-molecule OLEDs fabricated using a solution process. We report very efficient solution-processed simple-structured small-molecule OLEDs that use novel universal electron-transporting host materials based on tetraphenylsilane with pyridine moieties. These materials have wide band gaps, high triplet energy levels, and good solution processabilities; they provide balanced charge transport in a mixed-host emitting layer. Orange-red (~97.5 cd/A, ~35.5% photons per electron), green (~101.5 cd/A, ~29.0% photons per electron), and white (~74.2 cd/A, ~28.5% photons per electron) phosphorescent OLEDs exhibited the highest recorded electroluminescent efficiencies of solution-processed OLEDs reported to date. We also demonstrate a solution-processed flexible solid-state lighting device as a potential application of our devices. PMID:27819053

Study on cold head structure of a 300 Hz thermoacoustically driven pulse tube cryocooler

NASA Astrophysics Data System (ADS)

Yu, G. Y.; Wang, X. T.; Dai, W.; Luo, E. C.

2012-04-01

High reliability, compact size and potentially high thermal efficiency make the high frequency thermoacoustically-driven pulse tube cryocooler quite promising for space use. With continuous efforts, the lowest temperature and the thermal efficiency of the coupled system have been greatly improved. So far, a cold head temperature below 60 K has been achieved on such kind of cryocooler with the operation frequency of around 300 Hz. To further improve the thermal efficiency and expedite its practical application, this work focuses on studying the influence of cold head structure on the system performance. Substantial numerical simulations were firstly carried out, which revealed that the cold head structure would greatly influence the cooling power and the thermal efficiency. To validate the predictions, a lot of experiments have been done. The experiments and calculations are in reasonable agreement. With 500 W heating power input into the engine, a no-load temperature of 63 K and a cooling power of 1.16 W at 80 K have been obtained with parallel-plate cold head, indicating encouraging improvement of the thermal efficiency.

Preparation of arginine modified PEI-conjugated chitosan copolymer for DNA delivery.

PubMed

Zhang, Xi; Duan, Yajing; Wang, Dongfang; Bian, Fengling

2015-05-20

Polyethylenimine-conjugated chitosan (CS-PEI) and arginine modified polyethylenimine-conjugated chitosan (CS-PEI-Arg) were prepared, and the copolymers were characterized by FTIR, (1)H NMR, and XRD. The properties of these copolymers like plasmid DNA (pDNA) binding capacity, complexes' size and zeta potential, cytotoxicity and transfection efficiency were also evaluated. The results show that CS-PEI-Arg derivatives can bind pDNA thoroughly, and form complexes with sizes about 170 nm. Cytotoxicity assay in HepG2 and 293T cells show that CS-PEI-Arg has lower cytotoxicity compared with CS-PEI, which is similar to CS and far below that of PEI. In vitro luciferase assay show that CS-PEI-Arg has better transfection efficiency than CS-PEI, which is superior to that of PEI. The best transfection efficiency of CS-PEI-Arg (N/P = 50) is 2.3-fold, 4.2-fold of those of CS-PEI (N/P = 20) and PEI's (N/P = 10) efficiency respectively. These results display that CS-PEI-Arg is a promising candidate as an efficient gene vector. Copyright © 2014 Elsevier Ltd. All rights reserved.

Recent advances in exploitation of nanomaterial for arsenic removal from water: a review

NASA Astrophysics Data System (ADS)

Wong, WeiWen; Wong, H. Y.; Badruzzaman, A. Borhan M.; Goh, H. H.; Zaman, Mukter

2017-01-01

Recently, increasing research efforts have been made to exploit the enormous potential of nanotechnology and nanomaterial in the application of arsenic removal from water. As a result, there are myriad of types of nanomaterials being developed and studied for their arsenic removal capabilities. Nevertheless, challenges such as having a complete understanding of the material properties and removal mechanism make it difficult for researchers to engineer nanomaterials that are best suited for specific water treatment applications. In this review paper, a comprehensive review will be conducted on several selected categories of nanomaterials that possess promising prospects in arsenic removal application. The synthesis process, material properties, as well as arsenic removal performance and removal mechanisms of each of these nanomaterials will be discussed in detail. Fe-based nanomaterials, particularly iron oxide nanoparticles, have displayed advantages in arsenic removal due to their super-paramagnetic property. On the other hand, TiO2-based nanomaterials are the best candidates as photocatalytic arsenic removal agents, having been reported to have more than 200-fold increase in adsorption capacity under UV light irradiation. Zr-based nanomaterials have among the largest BET active area for adsorption—up to 630 m2 g-1—and it has been reported that amorphous ZrO2 performs better than crystalline ZrO2 nanoparticles, having about 1.77 times higher As(III) adsorption capacity. Although Cu-based nanomaterials are relatively uncommon as nano-adsorbents for arsenic in water, recent studies have demonstrated their potential in arsenic removal. CuO nanoparticles synthesized by Martinson et al were reported to have adsorption capacities up to 22.6 mg g-1 and 26.9 mg g-1 for As(V) and As(III) respectively. Among the nanomaterials that have been reviewed in this study, Mg-based nanomaterials were reported to have the highest maximum adsorption capacities for As(V) and As(III), at 378.79 mg g-1 and 643.84 mg g-1 respectively. By combining desired properties of different nanomaterials, composite nanomaterials can be made that have superior potential as efficient arsenic removal agents. Particularly, magnetic composite nanomaterials are interesting because the super-paramagnetic property, which allows efficient separation of nano-adsorbents in water, and high adsorption capacities, could be achieved simultaneously. For instance, Fe-Mn binary oxide nanowires have shown promising As(III) adsorption capacity at 171 mg g-1. Generally, nanomaterials used for arsenic removal face severe degradation in performance in the presence of competing ions in water, especially phosphate ions. This study will contribute to future research in developing nanomaterials used for arsenic removal that are highly efficient, environmentally friendly and cost-effective by providing a thorough, structured and detailed review on various nanomaterial candidates that have promising potential.

Pravastatin chitosan nanogels-loaded erythrocytes as a new delivery strategy for targeting liver cancer.

PubMed

Harisa, Gamaleldin I; Badran, Mohamed M; AlQahtani, Saeed A; Alanazi, Fars K; Attia, Sabry M

2016-01-01

Chitosan nanogels (CNG) are developed as one of the most promising carriers for cancer targeting. However, these carriers are rapidly eliminated from circulation by reticuloendothelial system (RES), which limits their application. Therefore, erythrocytes (ER) loaded CNG as multifunctional carrier may overcome the massive elimination of nanocarriers by RES. In this study, erythrocytes loaded pravastatin-chitosan nanogels (PR-CNG-ER) were utilized as a novel drug carrier to target liver cancer. Thus, PR-CNG formula was developed in nanosize, with good entrapment efficiency, drug loading and sustained release over 48 h. Then, PR-CNG loaded into ER were prepared by hypotonic preswelling technique. The resulting PR-CNG-ER showed 36.85% of entrapment efficiency, 66.82% of cell recovery and release consistent to that of hemoglobin over 48 h. Moreover, PR-CNG-ER exhibited negative zeta potential, increasing of hemolysis percent, marked phosphatidylserine exposure and stomatocytes shape compared to control unloaded erythrocytes. PR-CNG-ER reduced cells viability of HepG2 cells line by 28% compared to unloaded erythrocytes (UER). These results concluded that PR-CNG-ER are promising drug carriers to target liver cancer.

Pravastatin chitosan nanogels-loaded erythrocytes as a new delivery strategy for targeting liver cancer

PubMed Central

Harisa, Gamaleldin I.; Badran, Mohamed M.; AlQahtani, Saeed A.; Alanazi, Fars K.; Attia, Sabry M.

2015-01-01

Chitosan nanogels (CNG) are developed as one of the most promising carriers for cancer targeting. However, these carriers are rapidly eliminated from circulation by reticuloendothelial system (RES), which limits their application. Therefore, erythrocytes (ER) loaded CNG as multifunctional carrier may overcome the massive elimination of nanocarriers by RES. In this study, erythrocytes loaded pravastatin–chitosan nanogels (PR–CNG–ER) were utilized as a novel drug carrier to target liver cancer. Thus, PR–CNG formula was developed in nanosize, with good entrapment efficiency, drug loading and sustained release over 48 h. Then, PR–CNG loaded into ER were prepared by hypotonic preswelling technique. The resulting PR–CNG–ER showed 36.85% of entrapment efficiency, 66.82% of cell recovery and release consistent to that of hemoglobin over 48 h. Moreover, PR–CNG–ER exhibited negative zeta potential, increasing of hemolysis percent, marked phosphatidylserine exposure and stomatocytes shape compared to control unloaded erythrocytes. PR–CNG–ER reduced cells viability of HepG2 cells line by 28% compared to unloaded erythrocytes (UER). These results concluded that PR–CNG–ER are promising drug carriers to target liver cancer. PMID:26903771

A note on the efficiencies of sampling strategies in two-stage Bayesian regional fine mapping of a quantitative trait.

PubMed

Chen, Zhijian; Craiu, Radu V; Bull, Shelley B

2014-11-01

In focused studies designed to follow up associations detected in a genome-wide association study (GWAS), investigators can proceed to fine-map a genomic region by targeted sequencing or dense genotyping of all variants in the region, aiming to identify a functional sequence variant. For the analysis of a quantitative trait, we consider a Bayesian approach to fine-mapping study design that incorporates stratification according to a promising GWAS tag SNP in the same region. Improved cost-efficiency can be achieved when the fine-mapping phase incorporates a two-stage design, with identification of a smaller set of more promising variants in a subsample taken in stage 1, followed by their evaluation in an independent stage 2 subsample. To avoid the potential negative impact of genetic model misspecification on inference we incorporate genetic model selection based on posterior probabilities for each competing model. Our simulation study shows that, compared to simple random sampling that ignores genetic information from GWAS, tag-SNP-based stratified sample allocation methods reduce the number of variants continuing to stage 2 and are more likely to promote the functional sequence variant into confirmation studies. © 2014 WILEY PERIODICALS, INC.

Study of ground state optical transfer for ultracold alkali dimers

NASA Astrophysics Data System (ADS)

Bouloufa-Maafa, Nadia; Londono, Beatriz; Borsalino, Dimitri; Vexiau, Romain; Mahecha, Jorge; Dulieu, Olivier; Luc-Koenig, Eliane

2013-05-01

Control of molecular states by laser pulses offer promising potential applications. The manipulation of molecules by external fields requires precise knowledge of the molecular structure. Our motivation is to perform a detailed analysis of the spectroscopic properties of alkali dimers, with the aim to determine efficient optical paths to form molecules in the absolute ground state and to determine the optimal parameters of the optical lattices where those molecules are manipulated to avoid losses by collisions. To this end, we use state of the art molecular potentials, R-dependent spin-orbit coupling and transition dipole moment to perform our calculations. R-dependent SO coupling are of crucial importance because the transitions occur at internuclear distances where they are affected by this R-dependence. Efficient schemes to transfer RbCs, KRb and KCs to the absolute ground state as well as the optimal parameters of the optical lattices will be presented. This work was supported in part by ``Triangle de la Physique'' under contract 2008-007T-QCCM (Quantum Control of Cold Molecules).

Research Trends in Wireless Visual Sensor Networks When Exploiting Prioritization

PubMed Central

Costa, Daniel G.; Guedes, Luiz Affonso; Vasques, Francisco; Portugal, Paulo

2015-01-01

The development of wireless sensor networks for control and monitoring functions has created a vibrant investigation scenario, where many critical topics, such as communication efficiency and energy consumption, have been investigated in the past few years. However, when sensors are endowed with low-power cameras for visual monitoring, a new scope of challenges is raised, demanding new research efforts. In this context, the resource-constrained nature of sensor nodes has demanded the use of prioritization approaches as a practical mechanism to lower the transmission burden of visual data over wireless sensor networks. Many works in recent years have considered local-level prioritization parameters to enhance the overall performance of those networks, but global-level policies can potentially achieve better results in terms of visual monitoring efficiency. In this paper, we make a broad review of some recent works on priority-based optimizations in wireless visual sensor networks. Moreover, we envisage some research trends when exploiting prioritization, potentially fostering the development of promising optimizations for wireless sensor networks composed of visual sensors. PMID:25599425

Cell internalizable and intracellularly degradable cationic polyurethane micelles as a potential platform for efficient imaging and drug delivery.

PubMed

Ding, Mingming; Zeng, Xin; He, Xueling; Li, Jiehua; Tan, Hong; Fu, Qiang

2014-08-11

A cell internalizable and intracellularly degradable micellar system, assembled from multiblock polyurethanes bearing cell-penetrating gemini quaternary ammonium pendent groups in the side chain and redox-responsive disulfide linkages throughout the backbone, was developed for potential magnetic resonance imaging (MRI) and drug delivery. The nanocarrier is featured as a typical "cleavable core-internalizable shell-protective corona" architecture, which exhibits small size, positive surface charge, high loading capacity, and reduction-triggered destabilization. Furthermore, it can rapidly enter tumor cells and release its cargo in response to an intracellular level of glutathione, resulting in enhanced drug efficacy in vitro. The magnetic micelles loaded with superparamagnetic iron oxide (SPIO) nanoparticles demonstrate excellent MRI contrast enhancement, with T2 relaxivity found to be affected by the morphology of SPIO-clustering inside the micelle core. The multifunctional carrier with good cytocompatibility and nontoxic degradation products can serve as a promising theranostic candidate for efficient intracellular delivery of anticancer drugs and real-time monitoring of therapeutic effect.

Manipulating environmental stresses and stress tolerance of microalgae for enhanced production of lipids and value-added products-A review.

PubMed

Chen, Bailing; Wan, Chun; Mehmood, Muhammad Aamer; Chang, Jo-Shu; Bai, Fengwu; Zhao, Xinqing

2017-11-01

Microalgae have promising potential to produce lipids and a variety of high-value chemicals. Suitable stress conditions such as nitrogen starvation and high salinity could stimulate synthesis and accumulation of lipids and high-value products by microalgae, therefore, various stress-modification strategies were developed to manipulate and optimize cultivation processes to enhance bioproduction efficiency. On the other hand, advancements in omics-based technologies have boosted the research to globally understand microalgal gene regulation under stress conditions, which enable further improvement of production efficiency via genetic engineering. Moreover, integration of multi-omics data, synthetic biology design, and genetic engineering manipulations exhibits a tremendous potential in the betterment of microalgal biorefinery. This review discusses the process manipulation strategies and omics studies on understanding the regulation of metabolite biosynthesis under various stressful conditions, and proposes genetic engineering of microalgae to improve bioproduction via manipulating stress tolerance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental investigation of a 2.5 centimeter diameter Kaufman microthruster

NASA Technical Reports Server (NTRS)

Cohen, A. J.

1973-01-01

A 2.5-centimeter-diameter Kaufman electron bombardment microthruster was fabricated and tested. The microthruster design was based on the 15-centimeter-diameter SERT 2 and 5-centimeter-diameter Lewis experimental thruster designs. The microthruster with a two-grid system, operating at a net accelerating potential of 600 volts and an accelerator potential of 500 volts, produced a calculated 445 micronewton thrust when it was run with a 9-milliampere beam current. A glass grid was initially used in testing. Later a two-grid system was successfully incorporated. Both the propellant utilization efficiency and the total power efficiency were lower than for large-size advanced thrusters, as expected; but they were sufficiently high that 2.5-centimeter thrusters show promise for future space applications. Total power of the microthruster with an assumed 7-watt hollow-cathode neutralizer was less than 30 watts at a thrust level of 445 micronewton (100 Nu LBf). The hollow cathode was operated at zero tip heater power for power requirement tests.

Transportation Energy Futures: Combining Strategies for Deep Reductions in Energy Consumption and GHG Emissions (Brochure)

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

Not Available

2013-03-01

This fact sheet summarizes actions in the areas of light-duty vehicle, non-light-duty vehicle, fuel, and transportation demand that show promise for deep reductions in energy use. Energy efficient transportation strategies have the potential to simultaneously reduce oil consumption and greenhouse gas (GHG) emissions. The Transportation Energy Futures (TEF) project examined how the combination of multiple strategies could achieve deep reductions in GHG emissions and petroleum use on the order of 80%. Led by NREL, in collaboration with Argonne National Laboratory, the project's primary goal was to help inform domestic decisions about transportation energy strategies, priorities, and investments, with an emphasismore » on underexplored opportunities. TEF findings reveal three strategies with the potential to displace most transportation-related petroleum use and GHG emissions: 1) Stabilizing energy use in the transportation sector through efficiency and demand-side approaches. 2) Using additional advanced biofuels. 3) Expanding electric drivetrain technologies.« less

Pump and treat in low permeability media

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

Mackay, D.M.

1996-08-01

Pump and Treat (P&T) is a commonly applied technology whose primary promise for the low permeability environments of interest to these technology reviews is almost certainly containment of the problem. Conventional P&T would be expected to offer little promise of complete restoration in such environments, unless very long time frames (decades or centuries) are considered. A variety of approaches have been proposed to enhance the efficiency of P&T; some appear to offer little promise in low or mixed permeability environments, while others may offer more promise (e.g. hydro- or pneumatic-fracturing, which are described elsewhere in this document, and application ofmore » vacuum to the extraction well(s), which is a proprietary technology whose promise is currently difficult to assess objectively). Understanding the potential advantages and means of optimizing these enhancement approaches requires more understanding of the basic processes limiting P&T performance in low or mixed permeability media. These efforts are probably also necessary to understand the advantages and means of optimizing many of the very different remedial technologies that may be applicable to low or mixed permeability environments. Finally, since a reasonably certain capability of P&T is containment (i.e. prevention of further migration of contaminants), P&T may generally be required as a sort of safety net around sites at which the alternative technologies are being tested or applied. 23 refs.« less

Analysis of transport eco-efficiency scenarios to support sustainability assessment: a study on Dhaka City, Bangladesh.

PubMed

Iqbal, Asif; Allan, Andrew; Afroze, Shirina

2017-08-01

The study focused to assess the level of efficiency (of both emissions and service quality) that can be achieved for the transport system in Dhaka City, Bangladesh. The assessment technique attempted to quantify the extent of eco-efficiency achievable for the system modifications due to planning or strategy. The eco-efficiency analysis was facilitated with a detailed survey data on Dhaka City transport system, which was conducted for 9 months in 2012-2013. Line source modelling (CALINE4) was incorporated to estimate the on-road emission concentration. The eco-efficiency of the transport systems was assessed with the 'multi-criteria analysis' (MCA) technique that enabled the valuation of systems' qualitative and quantitative parameters. As per the analysis, driving indiscipline on road can alone promise about 47% reductions in emissions, which along with the number of private vehicles were the important stressors that restrict achieving eco-efficiency in Dhaka City. Detailed analysis of the transport system together with the potential transport system scenarios can offer a checklist to the policy makers enabling to identify the possible actions needed that can offer greater services to the dwellers against lesser emissions, which in turn can bring sustainability of the system.

Advancing Tissue Engineering: A Tale of Nano-, Micro-, and Macroscale Integration.

PubMed

Leijten, Jeroen; Rouwkema, Jeroen; Zhang, Yu Shrike; Nasajpour, Amir; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

2016-04-27

Tissue engineering has the potential to revolutionize the health care industry. Delivering on this promise requires the generation of efficient, controllable and predictable implants. The integration of nano- and microtechnologies into macroscale regenerative biomaterials plays an essential role in the generation of such implants, by enabling spatiotemporal control of the cellular microenvironment. Here we review the role, function and progress of a wide range of nano- and microtechnologies that are driving the advancements in the field of tissue engineering. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analytical Micromechanics Modeling Technique Developed for Ceramic Matrix Composites Analysis

NASA Technical Reports Server (NTRS)

Min, James B.

2005-01-01

Ceramic matrix composites (CMCs) promise many advantages for next-generation aerospace propulsion systems. Specifically, carbon-reinforced silicon carbide (C/SiC) CMCs enable higher operational temperatures and provide potential component weight savings by virtue of their high specific strength. These attributes may provide systemwide benefits. Higher operating temperatures lessen or eliminate the need for cooling, thereby reducing both fuel consumption and the complex hardware and plumbing required for heat management. This, in turn, lowers system weight, size, and complexity, while improving efficiency, reliability, and service life, resulting in overall lower operating costs.

Plastic efficiency of different implants used for repair of soft and bone tissue defects.

PubMed

Iriyanov, Yu M; Chernov, V F; Radchenko, S A; Chernov, A V

2013-08-01

The results of clinical and experimental morphological studies of regenerates forming after replacement of large defects of the abdominal wall and tibia with implants from different materials (polytetrafluoroethylene, reperene, prolene, titanium, and titanium nickelide) are analyzed. Study of the regenerate histology and fibroarchitectonics has shown good prospects of mesh constructions from titanium nickelide for effective surgical repair of these defects. The use of this implant seems to be theoretically well-based and promising, particularly under conditions of suppurative infection and low individual reparative regenerative potential.

Energy use in the marine transportation industry. Task II. Efficiency improvements. Draft report

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

Not Available

1977-06-02

Research and development areas that hold promise for maritime energy conservation are identified and evaluated. The methodology used in the evaluation of potential research areas and results, conclusions, and recommendations are presented. Fifteen programs are identified in four generic technologies and these are discussed in detail in appendices A-D. The areas are: main propulsion plants, propulsors, hydrodynamics, and vessel operations. Fuels are discussed briefly in appendix E. Additional information is presented on the generic US flag baseline operational and cost parameters; a sample output model is presented. (MCW)

A catalytic tethering strategy: simple aldehydes catalyze intermolecular alkene hydroaminations.

PubMed

MacDonald, Melissa J; Schipper, Derek J; Ng, Peter J; Moran, Joseph; Beauchemin, André M

2011-12-21

Herein we describe a catalytic tethering strategy in which simple aldehyde precatalysts enable, through temporary intramolecularity, room-temperature intermolecular hydroamination reactivity and the synthesis of vicinal diamines. The catalyst allows the formation of a mixed aminal from an allylic amine and a hydroxylamine, resulting in a facile intramolecular hydroamination event. The promising enantioselectivities obtained with a chiral aldehyde also highlight the potential of this catalytic tethering approach in asymmetric catalysis and demonstrate that efficient enantioinduction relying only on temporary intramolecularity is possible. © 2011 American Chemical Society

Novel Material Integration for Reliable and Energy-Efficient NEM Relay Technology

NASA Astrophysics Data System (ADS)

Chen, I.-Ru

Energy-efficient switching devices have become ever more important with the emergence of ubiquitous computing. NEM relays are promising to complement CMOS transistors as circuit building blocks for future ultra-low-power information processing, and as such have recently attracted significant attention from the semiconductor industry and researchers. Relay technology potentially can overcome the energy efficiency limit for conventional CMOS technology due to several key characteristics, including zero OFF-state leakage, abrupt switching behavior, and potentially very low active energy consumption. However, two key issues must be addressed for relay technology to reach its full potential: surface oxide formation at the contacting surfaces leading to increased ON-state resistance after switching, and high switching voltages due to strain gradient present within the relay structure. This dissertation advances NEM relay technology by investigating solutions to both of these pressing issues. Ruthenium, whose native oxide is conductive, is proposed as the contacting material to improve relay ON-state resistance stability. Ruthenium-contact relays are fabricated after overcoming several process integration challenges, and show superior ON-state resistance stability in electrical measurements and extended device lifetime. The relay structural film is optimized via stress matching among all layers within the structure, to provide lower strain gradient (below 10E-3/microm -1) and hence lower switching voltage. These advancements in relay technology, along with the integration of a metallic interconnect layer, enable complex relay-based circuit demonstration. In addition to the experimental efforts, this dissertation theoretically analyzes the energy efficiency limit of a NEM switch, which is generally believed to be limited by the surface adhesion energy. New compact (<1 microm2 footprint), low-voltage (<0.1 V) switch designs are proposed to overcome this limit. The results pave a pathway to scaled energy-efficient electronic device technology.

Flotation: A promising microalgae harvesting and dewatering technology for biofuels production.

PubMed

Ndikubwimana, Theoneste; Chang, Jingyu; Xiao, Zongyuan; Shao, Wenyao; Zeng, Xianhai; Ng, I-Son; Lu, Yinghua

2016-03-01

Microalgal biomass as renewable energy source is believed to be of great potential for reliable and sustainable biofuels production. However, microalgal biomass production is pinned by harvesting and dewatering stage thus hindering the developing and growing microalgae biotechnology industries. Flotation technology applied in mineral industry could be potentially applied in microalgae harvesting and dewatering, however substantial knowledge on different flotation units is essential. This paper presents an overview on different flotation units as promising cost-effective technologies for microalgae harvesting thus bestowing for further research in development and commercialization of microalgae based biofuels. Dispersed air flotation was found to be less energy consuming. Moreover, Jameson cell flotation and dispersed ozone flotation are believed to be energy efficient microalgae flotation approaches. Microalgae harvesting and dewatering by flotation is still at embryonic stage, therefore extended studies with the focus on life cycle assessment, sustainability of the flotation unit, optimization of the operating parameters using different algal species is imperative. Though there are a number of challenges in microalgae harvesting and dewatering, with well designed and developed cultivation, harvesting/dewatering, extraction and conversion technologies, progressively, microalgae technology will be of great potential for biological carbon sequestration, biofuels and biochemicals production. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Operator Guide: An Ambient Persuasive Interface in the Factory

NASA Astrophysics Data System (ADS)

Meschtscherjakov, Alexander; Reitberger, Wolfgang; Pöhr, Florian; Tscheligi, Manfred

In this paper we introduce the context of a semiconductor factory as a promising area for the application of innovative interaction approaches. In order to increase efficiency ambient persuasive interfaces, which influence the operators' behaviour to perform in an optimized way, could constitute a potential strategy. We present insights gained from qualitative studies conducted in a specific semiconductor factory and provide a description of typical work processes and already deployed interfaces in this context. These findings informed the design of a prototype of an ambient persuasive interface within this realm - the "Operator Guide". Its overall aim is to improve work efficiency, while still maintaining a minimal error rate. We provide a detailed description of the Operator Guide along with an outlook of the next steps within a user-centered design approach.

Synthesis and Photovoltaic Properties of a Copolymer based on thieno [2, 3-f] benzofuran and thienopyrroledione

NASA Astrophysics Data System (ADS)

Gao, Yueyue; Yang, Yulin; Zhang, Yong

2017-12-01

A novel donor-acceptor type conjugated polymer PTBFTPD based on two-dimensional (2D) conjugated alkylthienyl substituted thieno[2,3-f]benzofuran (TBF) and thienopyrroledione (TPD) unit, was synthesized and applied as donor material for bulk heterojunction solar cells. The novol polymer possesses a narrow bandgap of 1.83 eV, a deep HOMO energy level (-5.64 eV) and a closer π-π stacking. After conventional devices were fabricated using PTBFTPD as donor blending with PC70BM as acceptor, a power conversion efficiency (PCE) of 4.33% with a high open circuit voltage (Voc) of 1.09 V was obtained. The result indicates the promising potential of thieno [2, 3-f] benzofuran unit for high efficient polymer solar cells with a high voltage.

Hierarchical biointerfaces assembled by leukocyte-inspired particles for specifically recognizing cancer cells.

PubMed

Meng, Jingxin; Liu, Hongliang; Liu, Xueli; Yang, Gao; Zhang, Pengchao; Wang, Shutao; Jiang, Lei

2014-09-24

By mimicking certain biochemical and physical attributes of biological cells, bio-inspired particles have attracted great attention for potential biomedical applications based on cell-like biological functions. Inspired by leukocytes, hierarchical biointerfaces are designed and prepared based on specific molecules-modified leukocyte-inspired particles. These biointerfaces can efficiently recognize cancer cells from whole blood samples through the synergistic effect of molecular recognition and topographical interaction. Compared to flat, mono-micro or nano-biointerfaces, these micro/nano hierarchical biointerfaces are better able to promote specific recognition interactions, resulting in an enhanced cell-capture efficiency. It is anticipated that this study may provide promising guidance to develop new bio-inspired hierarchical biointerfaces for biomedical applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermal power generation during heat cycle near room temperature

NASA Astrophysics Data System (ADS)

Shibata, Takayuki; Fukuzumi, Yuya; Kobayashi, Wataru; Moritomo, Yutaka

2018-01-01

We demonstrate that a sodium-ion secondary battery (SIB)-type thermocell consisting of two types of Prussian blue analogue (PBA) with different electrochemical thermoelectric coefficients (S EC ≡ ∂V/∂T V and T are the redox potential and temperature, respectively) produces electrical energy during heat cycles. The device produces an electrical energy of 2.3 meV/PBA per heat cycle between 295 K (= T L) and 323 K (= T H). The ideal thermal efficiency (η = 1.0%), which is evaluated using the heat capacity (C = 4.16 meV/K) of ideal Na2Co[Fe(CN)6], reaches 11% of the Carnot efficiency (ηth = 8.7%). Our SIB-type thermocell is a promising thermoelectric device that harvests waste heat near room temperature.

Review on Metallic and Plastic Flexible Dye Sensitized Solar Cell

NASA Astrophysics Data System (ADS)

Yugis, A. R.; Mansa, R. F.; Sipaut, C. S.

2015-04-01

Dye sensitized solar cells (DSSCs) are a promising alternative for the development of a new generation of photovoltaic devices. DSSCs have promoted intense research due to their low cost and eco-friendly advantage over conventional silicon-based crystalline solar cells. In recent years, lightweight flexible types of DSSCs have attracted much intention because of drastic reduction in production cost and more extensive application. The substrate that used as electrode of the DSSCs has a dominant impact on the methods and materials that can be applied to the cell and consequently on the resulting performance of DSSCs. Furthermore, the substrates influence significantly the stability of the device. Although the power conversion efficiency still low compared to traditional glass based DSSCs, flexible DSSCs still have potential to be the most efficient and easily implemented technology.

Nonadiabatic Ab Initio Molecular Dynamics with the Floating Occupation Molecular Orbital-Complete Active Space Configuration Interaction Method [Non-Adiabatic Ab Initio Molecular Dynamics with Floating Occupation Molecular Orbitals CASCI Method

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

Hollas, Daniel; Sistik, Lukas; Hohenstein, Edward G.

Here, we show that the floating occupation molecular orbital complete active space configuration interaction (FOMO-CASCI) method is a promising alternative to the widely used complete active space self-consistent field (CASSCF) method in direct nonadiabatic dynamics simulations. We have simulated photodynamics of three archetypal molecules in photodynamics: ethylene, methaniminium cation, and malonaldehyde. We compared the time evolution of electronic populations and reaction mechanisms as revealed by the FOMO-CASCI and CASSCF approaches. Generally, the two approaches provide similar results. Some dynamical differences are observed, but these can be traced back to energetically minor differences in the potential energy surfaces. We suggest thatmore » the FOMO-CASCI method represents, due to its efficiency and stability, a promising approach for direct ab initio dynamics in the excited state.« less

Vertically-aligned BCN Nanotube Arrays with Superior Performance in Electrochemical capacitors

PubMed Central

Zhou, Junshuang; Li, Na; Gao, Faming; Zhao, Yufeng; Hou, Li; Xu, Ziming

2014-01-01

Electrochemical capacitors (EC) have received tremendous interest due to their high potential to satisfy the urgent demand in many advanced applications. The development of new electrode materials is considered to be the most promising approach to enhance the EC performance substantially. Herein, we present a high-capacity capacitor material based on vertically-aligned BC2N nanotube arrays (VA-BC2NNTAs) synthesized by low temperature solvothermal route. The obtained VA-BC2NNTAs display the good aligned nonbuckled tubular structure, which could indeed advantageously enhance capacitor performance. VA-BC2NNTAs exhibit an extremely high specific capacitance, 547 Fg−1, which is about 2–6 times larger than that of the presently available carbon-based materials. Meanwhile, VA-BC2NNTAs maintain an excellent rate capability and high durability. All these characteristics endow VA-BC2NNTAs an alternative promising candidate for an efficient electrode material for electrochemical capacitors (EC). PMID:25124300

Materials-Related Aspects of Thermochemical Water and Carbon Dioxide Splitting: A Review

PubMed Central

Roeb, Martin; Neises, Martina; Monnerie, Nathalie; Call, Friedemann; Simon, Heike; Sattler, Christian; Schmücker, Martin; Pitz-Paal, Robert

2012-01-01

Thermochemical multistep water- and CO2-splitting processes are promising options to face future energy problems. Particularly, the possible incorporation of solar power makes these processes sustainable and environmentally attractive since only water, CO2 and solar power are used; the concentrated solar energy is converted into storable and transportable fuels. One of the major barriers to technological success is the identification of suitable active materials like catalysts and redox materials exhibiting satisfactory durability, reactivity and efficiencies. Moreover, materials play an important role in the construction of key components and for the implementation in commercial solar plants. The most promising thermochemical water- and CO2-splitting processes are being described and discussed with respect to further development and future potential. The main materials-related challenges of those processes are being analyzed. Technical approaches and development progress in terms of solving them are addressed and assessed in this review.

Material Innovation in Advancing Organometal Halide Perovskite Functionality.

PubMed

Zheng, Fan; Saldana-Greco, Diomedes; Liu, Shi; Rappe, Andrew M

2015-12-03

Organometal halide perovskites (OMHPs) have garnered much attention recently for their unprecedented rate of increasing power conversion efficiency (PCE), positioning them as a promising basis for the next-generation photovoltaic devices. However, the gap between the rapid increasing PCE and the incomplete understanding of the structure-property-performance relationship prevents the realization of the true potential of OMHPs. This Perspective aims to provide a concise overview of the current status of OMHP research, highlighting the unique properties of OMHPs that are critical for solar applications but still not adequately explained. Stability and performance challenges of OMHP solar cells are discussed, calling upon combined experimental and theoretical efforts to address these challenges for pioneering commercialization of OMHP solar cells. Various material innovation strategies for improving the performance and stability of OMHPs are surveyed, showing that the OMHP architecture can serve as a promising and robust platform for the design and optimization of materials with desired functionalities.

Low-cost, light-switched, forward-osmosis desalination system

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

Warner, John C.

The looming water crisis is the second largest issue facing humanity after energy. In order to meet the increasing demand for clean water, new efficient and low-cost methods of water purification must be developed. A promising method for dry regions with sea borders is the desalination of seawater. While there remain many disadvantages to current desalination techniques, such as environmental pollution and high cost, there is a strong opportunity for new technology development in this area. In this Phase I program, the development of a light-switchable, low-cost desalination system was explored. The system requires photoselective switching of water solubility. Ninemore » new light-switchable spiropyran-based small molecule and polymeric materials were synthesized, and methods to evaluate their desalination potential were developed and utilized. Severable promising spiropyran analogues proved to be photoswitchable, but so far sufficient photoswitchablity of solubility for a commercial desalination system was not achieved. More development is required.« less

Model predictive control of a lean-burn gasoline engine coupled with a passive selective catalytic reduction system

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

Chen, Pingen; Lin, Qinghua; Prikhodko, Vitaly Y.

Lean-burn gasoline engines have demonstrated 10–20% engine efficiency gain over stoichiometric engines and are widely considered as a promising technology for meeting the 54.5 miles-per-gallon (mpg) Corporate Average Fuel Economy standard by 2025. Nevertheless, NOx emissions control for lean-burn gasoline for meeting the stringent EPA Tier 3 emission standards has been one of the main challenges towards the commercialization of highly-efficient lean-burn gasoline engines in the United States. Passive selective catalytic reduction (SCR) systems, which consist of a three-way catalyst and SCR, have demonstrated great potentials of effectively reducing NOx emissions for lean gasoline engines but may cause significant fuelmore » penalty due to ammonia generation via rich engine combustion. The purpose of this study is to develop a model-predictive control (MPC) scheme for a lean-burn gasoline engine coupled with a passive SCR system to minimize the fuel penalty associated with passive SCR operation while satisfying stringent NOx and NH3 emissions requirements. Simulation results demonstrate that the MPC-based control can reduce the fuel penalty by 47.7% in a simulated US06 cycle and 32.0% in a simulated UDDS cycle, compared to the baseline control, while achieving over 96% deNOx efficiency and less than 15 ppm tailpipe ammonia slip. The proposed MPC control can potentially enable high engine efficiency gain for highly-efficient lean-burn gasoline engine while meeting the stringent EPA Tier 3 emission standards.« less

Biosensors for breast cancer diagnosis: A review of bioreceptors, biotransducers and signal amplification strategies.

PubMed

Mittal, Sunil; Kaur, Hardeep; Gautam, Nandini; Mantha, Anil K

2017-02-15

Breast cancer is highly prevalent in females and accounts for second highest number of deaths, worldwide. Cumbersome, expensive and time consuming detection techniques presently available for detection of breast cancer potentiates the need for development of novel, specific and ultrasensitive devices. Biosensors are the promising and selective detection devices which hold immense potential as point of care (POC) tools. Present review comprehensively scrutinizes various breast cancer biosensors developed so far and their technical evaluation with respect to efficiency and potency of selected bioreceptors and biotransducers. Use of glycoproteins, DNA biomarkers, micro-RNA, circulatory tumor cells (CTC) and some potential biomarkers are introduced briefly. The review also discusses various strategies used in signal amplification such as nanomaterials, redox mediators, p19 protein, duplex specific nucleases (DSN) and redox cycling. Copyright © 2016 Elsevier B.V. All rights reserved.

Efficient generation of hPSC-derived midbrain dopaminergic neurons in a fully defined, scalable, 3D biomaterial platform

PubMed Central

Adil, Maroof M.; Rodrigues, Gonçalo M. C.; Kulkarni, Rishikesh U.; Rao, Antara T.; Chernavsky, Nicole E.; Miller, Evan W.; Schaffer, David V.

2017-01-01

Pluripotent stem cells (PSCs) have major potential as an unlimited source of functional cells for many biomedical applications; however, the development of cell manufacturing systems to enable this promise faces many challenges. For example, there have been major recent advances in the generation of midbrain dopaminergic (mDA) neurons from stem cells for Parkinson’s Disease (PD) therapy; however, production of these cells typically involves undefined components and difficult to scale 2D culture formats. Here, we used a fully defined, 3D, thermoresponsive biomaterial platform to rapidly generate large numbers of action-potential firing mDA neurons after 25 days of differentiation (~40% tyrosine hydroxylase (TH) positive, maturing into 25% cells exhibiting mDA neuron-like spiking behavior). Importantly, mDA neurons generated in 3D exhibited a 30-fold increase in viability upon implantation into rat striatum compared to neurons generated on 2D, consistent with the elevated expression of survival markers FOXA2 and EN1 in 3D. A defined, scalable, and resource-efficient cell culture platform can thus rapidly generate high quality differentiated cells, both neurons and potentially other cell types, with strong potential to accelerate both basic and translational research. PMID:28091566

A novel strategy for highly efficient isolation and analysis of circulating tumor-specific cell-free DNA from lung cancer patients using a reusable conducting polymer nanostructure.

PubMed

Lee, HyungJae; Jeon, SeungHyun; Seo, Jin-Suck; Goh, Sung-Ho; Han, Ji-Youn; Cho, Youngnam

2016-09-01

We have developed a reusable nanostructured polypyrrole nanochip and demonstrated its use in the electric field-mediated recovery of circulating cell-free DNA (cfDNA) from the plasma of lung cancer patients. Although cfDNA has been recognized and widely studied as a versatile and promising biomarker for the diagnosis and prognosis of cancers, the lack of efficient strategies to directly isolate cfDNA from the plasma has become a great hindrance to its potential clinical use. As a proof-of-concept study, we demonstrated a technique for the rapid and efficient isolation of cfDNA with high yield and purity. In particular, the synergistic effects of the electro-activity and the nanostructured features of the polypyrrole polymer enabled repeated retrieval of cfDNA using a single platform. Moreover, polypyrrole nanochip facilitated the amplification of tumor-specific DNA fragments from the plasma samples of patients with lung cancer characterized by mutations in exons 21 of the epidermal growth factor receptor gene (EGFR). Overall, the proposed polypyrrole nanochip has enormous potential for industrial and clinical applications with significantly enhanced efficiency in the recovery of tumor-associated circulating cfDNA. This may ultimately contribute to more robust and reliable evaluation of gene mutations in peripheral blood. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of heterocyclic-based head group modifications on the structure-activity relationship of tocopherol-based lipids for non-viral gene delivery.

PubMed

Gosangi, Mallikarjun; Mujahid, Thasneem Yoosuf; Gopal, Vijaya; Patri, Srilakshmi V

2016-07-12

Gene therapy, a promising strategy for the delivery of therapeutic nucleic acids, is greatly dependent on the development of efficient vectors. In this study, we designed and synthesized several tocopherol-based lipids varying in the head group region. Here, we present the structure-activity relationship of stable aqueous suspensions of lipids that were synthetically prepared and formulated with 1,2-dioleoyl phosphatidyl ethanolamine (DOPE) as the co-lipid. The physicochemical properties such as the hydrodynamic size, zeta potential, stability and morphology of these formulations were investigated. Interaction with plasmid DNA was clearly demonstrated through gel binding and EtBr displacement assays. Further, the transfection potential was examined in mouse neuroblastoma Neuro-2a, hepatocarcinoma HepG2, human embryonic kidney and Chinese hamster ovarian cell lines, all of different origins. Cell-uptake assays with N-methylpiperidinium, N-methylmorpholinium, N-methylimidazolium and N,N-dimethylaminopyridinium head group containing formulations evidently depicted efficient cell uptake as observed by particulate cytoplasmic fluorescence. Trafficking of lipoplexes using an endocytic marker and rhodamine-labeled phospholipid DHPE indicated that the lipoplexes were not sequestered in the lysosomes. Importantly, lipoplexes were non-toxic and mediated good transfection efficiency as analyzed by β-Gal and GFP reporter gene expression assays which established the superior activity of lipids whose structures correlate strongly with the transfection efficiency.

Low-Temperature Solution-Processed ZnSe Electron Transport Layer for Efficient Planar Perovskite Solar Cells with Negligible Hysteresis and Improved Photostability.

PubMed

Li, Xin; Yang, Junyou; Jiang, Qinghui; Lai, Hui; Li, Shuiping; Xin, Jiwu; Chu, Weijing; Hou, Jingdi

2018-05-15

For a typical perovskite solar cell (PKSC), the electron transport layer (ETL) has a great effect on device performance and stability. Herein, we manifest that low-temperature solution-processed ZnSe can be used as a potential ETL for PKSCs. Our optimized device with ZnSe ETL has achieved a high power conversion efficiency (PCE) of 17.78% with negligible hysteresis, compared with the TiO 2 based cell (13.76%). This enhanced photovoltaic performance is attributed to the suitable band alignment, high electron mobility, and reduced charge accumulation at the interface of ETL/perovskite. Encouraging results were obtained when the thin layer of ZnSe cooperated with TiO 2 . It shows that the device based on the TiO 2 /ZnSe ETL with cascade conduction band level can effectively reduce the interfacial charge recombination and promote carrier transfer with the champion PCE of 18.57%. In addition, the ZnSe-based device exhibits a better photostability than the control device due to the greater ultraviolet (UV) light harvesting of the ZnSe layer, which can efficiently prevent the perovskite film from intense UV-light exposure to avoid associated degradation. Consequently, our results present that a promising ETL can be a potential candidate of the n-type ETL for commercialization of efficient and photostable PKSCs.

Curcumin conjugated with PLGA potentiates sustainability, anti-proliferative activity and apoptosis in human colon carcinoma cells.

PubMed

Waghela, Bhargav N; Sharma, Anupama; Dhumale, Suhashini; Pandey, Shashibahl M; Pathak, Chandramani

2015-01-01

Curcumin, an ingredient of turmeric, exhibits a variety of biological activities such as anti-inflammatory, anti-atherosclerotic, anti-proliferative, anti-oxidant, anti-cancer and anti-metastatic. It is a highly pleiotropic molecule that inhibits cell proliferation and induces apoptosis in cancer cells. Despite its imperative biological activities, chemical instability, photo-instability and poor bioavailability limits its utilization as an effective therapeutic agent. Therefore, enhancing the bioavailability of curcumin may improve its therapeutic index for clinical setting. In the present study, we have conjugated curcumin with a biodegradable polymer Poly (D, L-lactic-co-glycolic acid) and evaluated its apoptotic potential in human colon carcinoma cells (HCT 116). The results show that curcumin-PLGA conjugate efficiently inhibits cell proliferation and cell survival in human colon carcinoma cells as compared to native curcumin. Additionally, curcumin conjugated with PLGA shows improved cellular uptake and exhibits controlled release at physiological pH as compared to native curcumin. The curcumin-PLGA conjugate efficiently activates the cascade of caspases and promotes intrinsic apoptotic signaling. Thus, the results suggest that conjugation potentiates the sustainability, anti-proliferative and apoptotic activity of curcumin. This approach could be a promising strategy to improve the therapeutic index of cancer therapy.

Electrochemically assisted photocatalysis: Highly efficient treatment using thermal titanium oxides doped and non-doped electrodes for water disinfection.

PubMed

Dos Santos, Andreia Betina Kreuser; Claro, Elis Marina Turini; Montagnolli, Renato Nallin; Cruz, Jaqueline Matos; Lopes, Paulo Renato Matos; Bidoia, Ederio Dino

2017-12-15

Electrochemically assisted photocatalysis (by electronic drainage) is a highly promising method for disinfection of water. In this research, the efficiency of photolytic oxidation using UV-A radiation and electrochemically assisted photocatalysis (with electric potential of 1.5 V) was studied by using electrodes prepared by thermal treatment and doped with silver, for inactivation of Escherichia coli and Staphylococcus aureus. The Chick-Watson microorganism inactivation model was applied and the electrical energy consumption of the process was calculated. It was observed no significant inactivation of microorganisms when UV-A light or electric potential were applied separately. However, the electrochemically assisted photocatalytic process, with Ag-doped electrode completely inactivated the microbial population after 10 (E. coli) and 60 min (S. aureus). The best performing non-doped electrodes achieved 52.74% (E. coli) and 44.09% (S. aureus) inactivation rates after 60 min. Thus, electrochemically assisted photocatalytic activity was not only effective for the inactivation of microorganisms, but also notably low on electrical energy consumption during the treatment due to small current and low electric potential applied. Copyright © 2017 Elsevier Ltd. All rights reserved.

Towards the development of new phosphors with reduced content of rare earth elements: Structural and optical characterization of Ce:Tb: Al{sub 2}SiO{sub 5}

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

Chiriu, D.; Stagi, L.; Carbonaro, C.M.

2016-05-15

Highlights: • A new promising inert matrix as host of luminescent ions is proposed. • Al2SiO5 matrix is free from Rare earths (critical raw materials). • Doping the matrix with Ce and Tb we obtain an efficient green emitter. • Cerium acts as sensitizer for Terbium emission. - Abstract: A new promising inert matrix as host of luminescent ions is proposed. Al2SiO5 samples, doped with rare earths (Ce, Tb single doped and co-doped) are proposed as good prospect for the development of new UV–vis converter with reduced content of rare earths elements. Structural characterization by Raman, XRD spectroscopy and TEMmore » imaging reveals the sillimanite phase and nano sized dimension of the investigated powders. Optical characterization by steady time and time resolved emission spectroscopy for the single doped and co-doped samples allows to identify an efficient energy transfer from Ce to Tb ions under near UV excitation wavelength. The intense green emission observed in the Ce:Tb co-doped Al2SiO5 system suggests its potential application as efficient blue pumped green emitter phosphor to be exploited for white LED: to this purpose we tested the compound in combination with a red emitting doping ion recording for Ce:Tb:Cr:ASO system a correlated color temperature of 6720 K.« less

Preparation and Application of Electrodes in Capacitive Deionization (CDI): a State-of-Art Review.

PubMed

Jia, Baoping; Zhang, Wei

2016-12-01

As a promising desalination technology, capacitive deionization (CDI) have shown practicality and cost-effectiveness in brackish water treatment. Developing more efficient electrode materials is the key to improving salt removal performance. This work reviewed current progress on electrode fabrication in application of CDI. Fundamental principal (e.g. EDL theory and adsorption isotherms) and process factors (e.g. pore distribution, potential, salt type and concentration) of CDI performance were presented first. It was then followed by in-depth discussion and comparison on properties and fabrication technique of different electrodes, including carbon aerogel, activated carbon, carbon nanotubes, graphene and ordered mesoporous carbon. Finally, polyaniline as conductive polymer and its potential application as CDI electrode-enhancing materials were also discussed.

Near unity ultraviolet absorption in graphene without patterning

NASA Astrophysics Data System (ADS)

Zhu, Jinfeng; Yan, Shuang; Feng, Naixing; Ye, Longfang; Ou, Jun-Yu; Liu, Qing Huo

2018-04-01

Enhancing the light-matter interaction of graphene is an important issue for related photonic devices and applications. In view of its potential ultraviolet applications, we aim to achieve extremely high ultraviolet absorption in graphene without any nanostructure or microstructure patterning. By manipulating the polarization and angle of incident light, the ultraviolet power can be sufficiently coupled to the optical dissipation of graphene based on single-channel coherent perfect absorption in an optimized multilayered thin film structure. The ultraviolet absorbance ratios of single and four atomic graphene layers are enhanced up to 71.4% and 92.2%, respectively. Our research provides a simple and efficient scheme to trap ultraviolet light for developing promising photonic and optoelectronic devices based on graphene and potentially other 2D materials.

Elastin-like polypeptide matrices for enhancing adeno-associated virus-mediated gene delivery to human neural stem cells.

PubMed

Kim, J-S; Chu, H S; Park, K I; Won, J-I; Jang, J-H

2012-03-01

The successful development of efficient and safe gene delivery vectors continues to be a major obstacle to gene delivery in stem cells. In this study, we have developed an elastin-like polypeptide (ELP)-mediated adeno-associated virus (AAV) delivery system for transducing fibroblasts and human neural stem cells (hNSCs). AAVs have significant promise as therapeutic vectors because of their safety and potential for use in gene targeting in stem cell research. ELP has been recently employed as a biologically inspired 'smart' biomaterial that exhibits an inverse temperature phase transition, thereby demonstrating promise as a novel drug carrier. The ELP that was investigated in this study was composed of a repetitive penta-peptide with [Val-Pro-Gly-Val-Gly]. A novel AAV variant, AAV r3.45, which was previously engineered by directed evolution to enhance transduction in rat NSCs, was nonspecifically immobilized onto ELPs that were adsorbed beforehand on a tissue culture polystyrene surface (TCPS). The presence of different ELP quantities on the TCPS led to variations in surface morphology, roughness and wettability, which were ultimately key factors in the modulation of cellular transduction. Importantly, with substantially reduced viral quantities compared with bolus delivery, ELP-mediated AAV delivery significantly enhanced delivery efficiency in fibroblasts and hNSCs, which have great potential for use in tissue engineering applications and neurodegenerative disorder treatments, respectively. The enhancement of cellular transduction in stem cells, as well as the feasibility of ELPs for utilization in three-dimensional scaffolds, will contribute to the advancement of gene therapy for stem cell research and tissue regenerative medicine.

Efficient Synthesis and Discovery of Schiff Bases as Potent Cholinesterase Inhibitors.

PubMed

Razik, Basma M Abd; Osman, Hasnah; Ezzat, Mohammed O; Basiri, Alireza; Salhin, Abdussalam; Kia, Yalda; Murugaiyah, Vikneswaran

2016-01-01

The search for new cholinesterase inhibitors is still a promising approach for management of Alzheimer`s disease. Schiff bases are considered as important class of organic compounds, which have wide range of applications including as enzyme inhibitors. In the present study, a new green ionic liquid mediated strategy was developed for convenient synthesis of two series of Schiff bases 3(a-j) and 5(a-j) as potential cholinesterase inhibitors using aromatic aldehydes and primary amines in [bmim]Br. The synthesized compounds were evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential by modified Ellman's method. The molecular interactions between the most active compound and the enzyme were analyzed by molecular docking. Among them, 3j displayed higher inhibitory activities than reference drug, galanthamine, with IC50 values of 2.05 and 5.77 µM, for AChE and BChE, respectively. Interestingly, all the compounds except 3b displayed higher BChE inhibitions than galanthamine with IC50 values ranging from 5.77 to 18.52 µM. Molecular docking of compound 3j inside the TcAChE and hBChE completely coincided with the inhibitory activities observed. The compound forms strong hydrogen bonding at the peripheral anionic site of AChE whereas on BChE, it had hydrophobic and mild polar interactions. An efficient and eco-friendly synthetic methodology has been developed to synthesize Schiff bases in a very short reaction time and excellent yields in ionic solvent, whereby the compounds from series 3 showed promising cholinesterase inhibitory activity.

Key challenges and recent progress in batteries, fuel cells, and hydrogen storage for clean energy systems

NASA Astrophysics Data System (ADS)

Chalk, Steven G.; Miller, James F.

Reducing or eliminating the dependency on petroleum of transportation systems is a major element of US energy research activities. Batteries are a key enabling technology for the development of clean, fuel-efficient vehicles and are key to making today's hybrid electric vehicles a success. Fuel cells are the key enabling technology for a future hydrogen economy and have the potential to revolutionize the way we power our nations, offering cleaner, more efficient alternatives to today's technology. Additionally fuel cells are significantly more energy efficient than combustion-based power generation technologies. Fuel cells are projected to have energy efficiency twice that of internal combustion engines. However before fuel cells can realize their potential, significant challenges remain. The two most important are cost and durability for both automotive and stationary applications. Recent electrocatalyst developments have shown that Pt alloy catalysts have increased activity and greater durability than Pt catalysts. The durability of conventional fluorocarbon membranes is improving, and hydrocarbon-based membranes have also shown promise of equaling the performance of fluorocarbon membranes at lower cost. Recent announcements have also provided indications that fuel cells can start from freezing conditions without significant deterioration. Hydrogen storage systems for vehicles are inadequate to meet customer driving range expectations (>300 miles or 500 km) without intrusion into vehicle cargo or passenger space. The United States Department of Energy has established three centers of Excellence for hydrogen storage materials development. The centers are focused on complex metal hydrides that can be regenerated onboard a vehicle, chemical hydrides that require off-board reprocessing, and carbon-based storage materials. Recent developments have shown progress toward the 2010 DOE targets. In addition DOE has established an independent storage material testing center to verify storage capacity of promising materials. These developments point to a viable path to achieving the DOE/FreedomCAR cost and performance goals. The transition to hydrogen-powered fuel cell vehicles will occur over the next 10-15 years. In the interim, fossil fuel consumption will be reduced by increased penetration of battery/gasoline hybrid cars.

A fundamental analysis of means of producing and storing energy

NASA Astrophysics Data System (ADS)

Briggs, Michael S.

The goal of this dissertation is to examine some of the most promising non-fossil means for producing electricity and storing energy for transportation, to provide a thorough and (hopefully) unbiased assessment of which hold the most promise, and therefore warrant further research focus. Additionally, recommendations are made for potential means for improving proposed or existing technologies, in particular the technology of a new subcritical reactor design using an electronuclear driver and thermal transmutation of transuranic actinides. The high energy density of liquid hydrocarbon fuels is ideal for transportation applications, but our ability to sustainably produce such fuels (i.e. biofuels) is limited by the low photosynthetic efficiency achieved by plants. While some proposals are made herein to make the most of the potential of biofuels, their limitations ultimately will require the storage of electrical energy (in batteries, hydrogen, or mechanical energy storage) if we are to eliminate our dependence on petroleum for transportation. The outcome of this analysis is that lithium-ion batteries are best suited for such an application. This is based on a significantly better net efficiency with only moderately lower energy density compared to the best means of storing hydrogen, and no additional infrastructure requirements. The analysis also indicates the direction research should take to further improve lithium-ion batteries. Since the sustainability of electric vehicles depends on the means of producing electricity, a focus of this dissertation is assessing the potential to produce electricity with advanced nuclear fission and fusion reactors. While magnetic and inertial confinement fusion are interesting from the standpoint of the plasma and nuclear physics involved, the analysis presented here illustrates that the potential for commercial electricity production with either is slim, with several potential "deal breakers." Further, muon catalyzed fusion is shown to offer no practical means of producing net energy. Furthermore, fusion fuels other than Deuterium-Tritium (DT) have triple product requirements roughly two orders of magnitude greater for net energy production. The analysis of a "catalyzed deuterium" plasma presented herein shows it to be less promising than previous analyses have indicated. The flux of 14.1 MeV neutrons from a DT plasma presents a significant challenge that is likely to limit or prevent commercialization of DT fusion power. The primary alternative approach that may become viable is a so-called helium catalyzed DD cycle. However, there are two significant challenges (the need for active tritium removal and the large onsite tritium inventory) that must be addressed for this option to have significant potential. Greater focus therefore should be placed on advanced fission reactors, in particular thermal thorium reactors and driven subcritical reactors, such as of the general design proposed in this dissertation.

Organic and perovskite solar cells: Working principles, materials and interfaces.

PubMed

Marinova, Nevena; Valero, Silvia; Delgado, Juan Luis

2017-02-15

In the last decades organic solar cells (OSCs) have been considered as a promising photovoltaic technology with the potential to provide reasonable power conversion efficiencies combined with low cost and easy processability. Unexpectedly, Perovskite Solar Cells (PSCs) have experienced unprecedented rise in Power Conversion Efficiency (PCE) thus emerging as a highly efficient photovoltaic technology. OSCs and PSCs are two different kind of devices with distinct charge generation mechanism, which however share some similarities in the materials processing, thus standard strategies developed for OSCs are currently being employed in PSCs. In this article, we recapitulate the main processes in these two types of photovoltaic technologies with an emphasis on interfacial processes and interfacial modification, spotlighting the materials and newest approaches in the interfacial engineering. We discuss on the relevance of well-known materials coming from the OSCs field, which are now being tested in the PSCs field, while maintaining a focus on the importance of the material design for highly efficient, stable and accessible solar cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Fully Solution-Processed Tandem White Quantum-Dot Light-Emitting Diode with an External Quantum Efficiency Exceeding 25.

PubMed

Jiang, Congbiao; Zou, Jianhua; Liu, Yu; Song, Chen; He, Zhiwei; Zhong, Zhenji; Wang, Jian; Yip, Hin-Lap; Peng, Junbiao; Cao, Yong

2018-06-15

Solution-processed electroluminescent tandem white quantum-dot light-emitting diodes (TWQLEDs) have the advantages of being low-cost and high-efficiency and having a wide color gamut combined with color filters, making this a promising backlight technology for high-resolution displays. However, TWQLEDs are rarely reported due to the challenge of designing device structures and the deterioration of film morphology with component layers that can be deposited from solutions. Here, we report an interconnecting layer with the optical, electrical, and mechanical properties required for fully solution-processed TWQLED. The optimized TWQLEDs exhibit a state-of-the-art current efficiency as high as 60.4 cd/A and an extremely high external quantum efficiency of 27.3% at a luminance of 100 000 cd/m 2 . A high color gamut of 124% NTSC 1931 standard can be achieved when combined with commercial color filters. These results represent the highest performance for solution-processed WQLEDs, unlocking the great application potential of TWQLEDs as backlights for new-generation displays.

Correlation between Thermodynamic Efficiency and Ecological Cyclicity for Thermodynamic Power Cycles

PubMed Central

Layton, Astrid; Reap, John; Bras, Bert; Weissburg, Marc

2012-01-01

A sustainable global community requires the successful integration of environment and engineering. In the public and private sectors, designing cyclical (“closed loop”) resource networks increasingly appears as a strategy employed to improve resource efficiency and reduce environmental impacts. Patterning industrial networks on ecological ones has been shown to provide significant improvements at multiple levels. Here, we apply the biological metric cyclicity to 28 familiar thermodynamic power cycles of increasing complexity. These cycles, composed of turbines and the like, are scientifically very different from natural ecosystems. Despite this difference, the application results in a positive correlation between the maximum thermal efficiency and the cyclic structure of the cycles. The immediate impact of these findings results in a simple method for comparing cycles to one another, higher cyclicity values pointing to those cycles which have the potential for a higher maximum thermal efficiency. Such a strong correlation has the promise of impacting both natural ecology and engineering thermodynamics and provides a clear motivation to look for more fundamental scientific connections between natural and engineered systems. PMID:23251638

CRISPR/Cas9 nuclease-mediated gene knock-in in bovine-induced pluripotent cells.

PubMed

Heo, Young Tae; Quan, Xiaoyuan; Xu, Yong Nan; Baek, Soonbong; Choi, Hwan; Kim, Nam-Hyung; Kim, Jongpil

2015-02-01

Efficient and precise genetic engineering in livestock such as cattle holds great promise in agriculture and biomedicine. However, techniques that generate pluripotent stem cells, as well as reliable tools for gene targeting in livestock, are still inefficient, and thus not routinely used. Here, we report highly efficient gene targeting in the bovine genome using bovine pluripotent cells and clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 nuclease. First, we generate induced pluripotent stem cells (iPSCs) from bovine somatic fibroblasts by the ectopic expression of yamanaka factors and GSK3β and MEK inhibitor (2i) treatment. We observed that these bovine iPSCs are highly similar to naïve pluripotent stem cells with regard to gene expression and developmental potential in teratomas. Moreover, CRISPR/Cas9 nuclease, which was specific for the bovine NANOG locus, showed highly efficient editing of the bovine genome in bovine iPSCs and embryos. To conclude, CRISPR/Cas9 nuclease-mediated homologous recombination targeting in bovine pluripotent cells is an efficient gene editing method that can be used to generate transgenic livestock in the future.

Nitrogen-doped diamond electrode shows high performance for electrochemical reduction of nitrobenzene.

PubMed

Zhang, Qing; Liu, Yanming; Chen, Shuo; Quan, Xie; Yu, Hongtao

2014-01-30

Effective electrode materials are critical to electrochemical reduction, which is a promising method to pre-treat anti-oxidative and bio-refractory wastewater. Herein, nitrogen-doped diamond (NDD) electrodes that possess superior electrocatalytic properties for reduction were fabricated by microwave-plasma-enhanced chemical vapor deposition technology. Nitrobenzene (NB) was chosen as the probe compound to investigate the material's electro-reduction activity. The effects of potential, electrolyte concentration and pH on NB reduction and aniline (AN) formation efficiencies were studied. NDD exhibited high electrocatalytic activity and selectivity for reduction of NB to AN. The NB removal efficiency and AN formation efficiency were 96.5% and 88.4% under optimal conditions, respectively; these values were 1.13 and 3.38 times higher than those of graphite electrodes. Coulombic efficiencies for NB removal and AN formation were 27.7% and 26.1%, respectively; these values were 4.70 and 16.6 times higher than those of graphite electrodes under identical conditions. LC-MS analysis revealed that the dominant reduction pathway on the NDD electrode was NB to phenylhydroxylamine (PHA) to AN. Copyright © 2013 Elsevier B.V. All rights reserved.

Nonepitaxial Thin-Film InP for Scalable and Efficient Photocathodes.

PubMed

Hettick, Mark; Zheng, Maxwell; Lin, Yongjing; Sutter-Fella, Carolin M; Ager, Joel W; Javey, Ali

2015-06-18

To date, some of the highest performance photocathodes of a photoelectrochemical (PEC) cell have been shown with single-crystalline p-type InP wafers, exhibiting half-cell solar-to-hydrogen conversion efficiencies of over 14%. However, the high cost of single-crystalline InP wafers may present a challenge for future large-scale industrial deployment. Analogous to solar cells, a thin-film approach could address the cost challenges by utilizing the benefits of the InP material while decreasing the use of expensive materials and processes. Here, we demonstrate this approach, using the newly developed thin-film vapor-liquid-solid (TF-VLS) nonepitaxial growth method combined with an atomic-layer deposition protection process to create thin-film InP photocathodes with large grain size and high performance, in the first reported solar device configuration generated by materials grown with this technique. Current-voltage measurements show a photocurrent (29.4 mA/cm(2)) and onset potential (630 mV) approaching single-crystalline wafers and an overall power conversion efficiency of 11.6%, making TF-VLS InP a promising photocathode for scalable and efficient solar hydrogen generation.

Enhancing the Effectiveness of Smoking Treatment Research: Conceptual Bases and Progress

PubMed Central

Baker, Timothy B.; Collins, Linda M.; Mermelstein, Robin; Piper, Megan E.; Schlam, Tanya R.; Cook, Jessica W.; Bolt, Daniel M.; Smith, Stevens S.; Jorenby, Douglas E.; Fraser, David; Loh, Wei-Yin; Theobald, Wendy E.; Fiore, Michael C.

2015-01-01

Background and aims A chronic care strategy could potentially enhance the reach and effectiveness of smoking treatment by providing effective interventions for all smokers, including those who are initially unwilling to quit. This paper describes the conceptual bases of a National Cancer Institute-funded research program designed to develop an optimized, comprehensive, chronic care smoking treatment. Methods This research is grounded in three methodological approaches: 1) the Phase-Based Model, which guides the selection of intervention components to be experimentally evaluated for the different phases of smoking treatment (motivation, preparation, cessation, and maintenance); 2) the Multiphase Optimization Strategy (MOST), which guides the screening of intervention components via efficient experimental designs and, ultimately, the assembly of promising components into an optimized treatment package; and 3) pragmatic research methods, such as electronic health record recruitment, that facilitate the efficient translation of research findings into clinical practice. Using this foundation and working in primary care clinics, we conducted three factorial experiments (reported in three accompanying articles) to screen 15 motivation, preparation, cessation, and maintenance phase intervention components for possible inclusion in a chronic care smoking treatment program. Results This research identified intervention components with relatively strong evidence of effectiveness at particular phases of smoking treatment and it demonstrated the efficiency of the MOST approach in terms both of the number of intervention components tested and of the richness of the information yielded. Conclusions A new, synthesized research approach efficiently evaluates multiple intervention components to identify promising components for every phase of smoking treatment. Many intervention components interact with one another, supporting the use of factorial experiments in smoking treatment development. PMID:26581974

Efficient Solar Energy Harvesting and Storage through a Robust Photocatalyst Driving Reversible Redox Reactions.

PubMed

Zhou, Yangen; Zhang, Shun; Ding, Yu; Zhang, Leyuan; Zhang, Changkun; Zhang, Xiaohong; Zhao, Yu; Yu, Guihua

2018-06-14

Simultaneous solar energy conversion and storage is receiving increasing interest for better utilization of the abundant yet intermittently available sunlight. Photoelectrodes driving nonspontaneous reversible redox reactions in solar-powered redox cells (SPRCs), which can deliver energy via the corresponding reverse reactions, present a cost-effective and promising approach for direct solar energy harvesting and storage. However, the lack of photoelectrodes having both high conversion efficiency and high durability becomes a bottleneck that hampers practical applications of SPRCs. Here, it is shown that a WO 3 -decorated BiVO 4 photoanode, without the need of extra electrocatalysts, can enable a single-photocatalyst-driven SPRC with a solar-to-output energy conversion efficiency as high as 1.25%. This SPRC presents stable performance over 20 solar energy storage/delivery cycles. The high efficiency and stability are attributed to the rapid redox reactions, the well-matched energy level, and the efficient light harvesting and charge separation of the prepared BiVO 4 . This demonstrated device system represents a potential alternative toward the development of low-cost, durable, and easy-to-implement solar energy technologies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mushrooms as Efficient Solar Steam-Generation Devices.

PubMed

Xu, Ning; Hu, Xiaozhen; Xu, Weichao; Li, Xiuqiang; Zhou, Lin; Zhu, Shining; Zhu, Jia

2017-07-01

Solar steam generation is emerging as a promising technology, for its potential in harvesting solar energy for various applications such as desalination and sterilization. Recent studies have reported a variety of artificial structures that are designed and fabricated to improve energy conversion efficiencies by enhancing solar absorption, heat localization, water supply, and vapor transportation. Mushrooms, as a kind of living organism, are surprisingly found to be efficient solar steam-generation devices for the first time. Natural and carbonized mushrooms can achieve ≈62% and ≈78% conversion efficiencies under 1 sun illumination, respectively. It is found that this capability of high solar steam generation is attributed to the unique natural structure of mushroom, umbrella-shaped black pileus, porous context, and fibrous stipe with a small cross section. These features not only provide efficient light absorption, water supply, and vapor escape, but also suppress three components of heat losses at the same time. These findings not only reveal the hidden talent of mushrooms as low-cost materials for solar steam generation, but also provide inspiration for the future development of high-performance solar thermal conversion devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Placement and efficiency effects on radiative forcing of solar installations

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

Burg, Brian R.; Ruch, Patrick; Paredes, Stephan

2015-09-28

The promise for harnessing solar energy being hampered by cost, triggered efforts to reduce them. As a consequence low-efficiency, low-cost photovoltaics (PV) panels prevail. Conversely, in the traditional energy sector efficiency is extremely important due to the direct costs associated to fuels. This also affects solar energy due to the radiative forcing caused by the dark solar panels. In this paper we extend the concept of energy payback time by including the effect of albedo change, which gives a better assessment of the system sustainability. We present an analysis on the short and medium term climate forcing effects of differentmore » solar collectors in Riyadh, Saudi Arabia and demonstrate that efficiency is important to reduce the collector area and cost. This also influences the embodied energy and the global warming potential. We show that a placement of a high concentration photovoltaic thermal solar power station outside of the city using a district cooling system has a double beneficial effect since it improves the solar conversion efficiency and reduces the energy demand for cooling in the city. We also explain the mechanisms of the current economic development of solar technologies and anticipate changes.« less

Cooperative electrocatalytic alcohol oxidation with electron-proton-transfer mediators.

PubMed

Badalyan, Artavazd; Stahl, Shannon S

2016-07-21

The electrochemical oxidation of alcohols is a major focus of energy and chemical conversion efforts, with potential applications ranging from fuel cells to biomass utilization and fine-chemical synthesis. Small-molecule electrocatalysts for processes of this type are promising targets for further development, as demonstrated by recent advances in nickel catalysts for electrochemical production and oxidation of hydrogen. Complexes with tethered amines that resemble the active site of hydrogenases have been shown both to catalyse hydrogen production (from protons and electrons) with rates far exceeding those of such enzymes and to mediate reversible electrocatalytic hydrogen production and oxidation with enzyme-like performance. Progress in electrocatalytic alcohol oxidation has been more modest. Nickel complexes similar to those used for hydrogen oxidation have been shown to mediate efficient electrochemical oxidation of benzyl alcohol, with a turnover frequency of 2.1 per second. These compounds exhibit poor reactivity with ethanol and methanol, however. Organic nitroxyls, such as TEMPO (2,2,6,6-tetramethyl-1-piperidine N-oxyl), are the most widely studied electrocatalysts for alcohol oxidation. These catalysts exhibit good activity (1–2 turnovers per second) with a wide range of alcohols and have great promise for electro-organic synthesis. Their use in energy-conversion applications, however, is limited by the high electrode potentials required to generate the reactive oxoammonium species. Here we report (2,2′-bipyridine)Cu/nitroxyl co-catalyst systems for electrochemical alcohol oxidation that proceed with much faster rates, while operating at an electrode potential a half-volt lower than that used for the TEMPO-only process. The (2,2′-bipyridine)Cu(II) and TEMPO redox partners exhibit cooperative reactivity and exploit the low-potential, proton-coupled TEMPO/TEMPOH redox process rather than the high-potential TEMPO/TEMPO+ process. The results show how electron-proton-transfer mediators, such as TEMPO, may be used in combination with first-row transition metals, such as copper, to achieve efficient two-electron electrochemical processes, thereby introducing a new concept for the development of non-precious-metal electrocatalysts.

Cooperative electrocatalytic alcohol oxidation with electron-proton-transfer mediators

NASA Astrophysics Data System (ADS)

Badalyan, Artavazd; Stahl, Shannon S.

2016-07-01

The electrochemical oxidation of alcohols is a major focus of energy and chemical conversion efforts, with potential applications ranging from fuel cells to biomass utilization and fine-chemical synthesis. Small-molecule electrocatalysts for processes of this type are promising targets for further development, as demonstrated by recent advances in nickel catalysts for electrochemical production and oxidation of hydrogen. Complexes with tethered amines that resemble the active site of hydrogenases have been shown both to catalyse hydrogen production (from protons and electrons) with rates far exceeding those of such enzymes and to mediate reversible electrocatalytic hydrogen production and oxidation with enzyme-like performance. Progress in electrocatalytic alcohol oxidation has been more modest. Nickel complexes similar to those used for hydrogen oxidation have been shown to mediate efficient electrochemical oxidation of benzyl alcohol, with a turnover frequency of 2.1 per second. These compounds exhibit poor reactivity with ethanol and methanol, however. Organic nitroxyls, such as TEMPO (2,2,6,6-tetramethyl-1-piperidine N-oxyl), are the most widely studied electrocatalysts for alcohol oxidation. These catalysts exhibit good activity (1-2 turnovers per second) with a wide range of alcohols and have great promise for electro-organic synthesis. Their use in energy-conversion applications, however, is limited by the high electrode potentials required to generate the reactive oxoammonium species. Here we report (2,2‧-bipyridine)Cu/nitroxyl co-catalyst systems for electrochemical alcohol oxidation that proceed with much faster rates, while operating at an electrode potential a half-volt lower than that used for the TEMPO-only process. The (2,2‧-bipyridine)Cu(II) and TEMPO redox partners exhibit cooperative reactivity and exploit the low-potential, proton-coupled TEMPO/TEMPOH redox process rather than the high-potential TEMPO/TEMPO+ process. The results show how electron-proton-transfer mediators, such as TEMPO, may be used in combination with first-row transition metals, such as copper, to achieve efficient two-electron electrochemical processes, thereby introducing a new concept for the development of non-precious-metal electrocatalysts.

SELF-HEALING NANOMATERIALS: MULTIMILLION-ATOM REACTIVE MOLECULAR DYNAMICS SIMULATIONS

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

Hakamata, Tomoya; Shimamura, Kohei; Shimojo, Fuyuki

Organometal halide perovskites are attracting great attention as promising material for solar cells because of their high power conversion efficiency. The high performance has been attributed to the existence of free charge carriers and their large diffusion lengths, but the nature of carrier transport at the atomistic level remains elusive. Here, nonadiabatic quantum molecular dynamics simulations elucidate the mechanisms underlying the excellent free-carrier transport in CH 3NH 3PbI 3. Pb and I sublattices act as disjunct pathways for rapid and balanced transport of photoexcited electrons and holes, respectively, while minimizing efficiency-degrading charge recombination. On the other hand, CH 3NH 3more » sublattice quickly screens out electrostatic electron-hole attraction to generate free carriers within 1 ps. Together this nano-architecture lets photoexcited electrons and holes dissociate instantaneously and travel far away to be harvested before dissipated as heat. As a result, this work provides much needed structure-property relationships and time-resolved information that potentially lead to rational design of efficient solar cells.« less

Ultrahigh Responsivity-Bandwidth Product in a Compact InP Nanopillar Phototransistor Directly Grown on Silicon

NASA Astrophysics Data System (ADS)

Ko, Wai Son; Bhattacharya, Indrasen; Tran, Thai-Truong D.; Ng, Kar Wei; Adair Gerke, Stephen; Chang-Hasnain, Connie

2016-09-01

Highly sensitive and fast photodetectors can enable low power, high bandwidth on-chip optical interconnects for silicon integrated electronics. III-V compound semiconductor direct-bandgap materials with high absorption coefficients are particularly promising for photodetection in energy-efficient optical links because of the potential to scale down the absorber size, and the resulting capacitance and dark current, while maintaining high quantum efficiency. We demonstrate a compact bipolar junction phototransistor with a high current gain (53.6), bandwidth (7 GHz) and responsivity (9.5 A/W) using a single crystalline indium phosphide nanopillar directly grown on a silicon substrate. Transistor gain is obtained at sub-picowatt optical power and collector bias close to the CMOS line voltage. The quantum efficiency-bandwidth product of 105 GHz is the highest for photodetectors on silicon. The bipolar junction phototransistor combines the receiver front end circuit and absorber into a monolithic integrated device, eliminating the wire capacitance between the detector and first amplifier stage.

Attached cultivation technology of microalgae for efficient biomass feedstock production.

PubMed

Liu, Tianzhong; Wang, Junfeng; Hu, Qiang; Cheng, Pengfei; Ji, Bei; Liu, Jinli; Chen, Yu; Zhang, Wei; Chen, Xiaoling; Chen, Lin; Gao, Lili; Ji, Chunli; Wang, Hui

2013-01-01

The potential of microalgae biofuel has not been realized because of low productivity and high costs associated with the current cultivation systems. In this paper, an attached cultivation method was introduced, in which microalgae cells grew on the surface of vertical artificial supporting material to form algal film. Multiple of the algal films were assembled in an array fashion to dilute solar irradiation to facilitate high photosynthetic efficiency. Results showed that a broad range of microalgae species can grow with this attached method. A biomass productivity of 50-80 g m(-2) d(-1) was obtained outdoors for Scenedesmus obliquus, corresponding to the photosynthetic efficiency of 5.2-8.3% (total solar radiation). This attached method also offers lots of possible advantages over traditional open ponds, such as on water saving, harvesting, contamination controlling and scale-up. The attached cultivation represents a promising technology for economically viable production of microalgae biofuels. Copyright © 2012 Elsevier Ltd. All rights reserved.

Metallic tin quantum sheets confined in graphene toward high-efficiency carbon dioxide electroreduction

NASA Astrophysics Data System (ADS)

Lei, Fengcai; Liu, Wei; Sun, Yongfu; Xu, Jiaqi; Liu, Katong; Liang, Liang; Yao, Tao; Pan, Bicai; Wei, Shiqiang; Xie, Yi

2016-09-01

Ultrathin metal layers can be highly active carbon dioxide electroreduction catalysts, but may also be prone to oxidation. Here we construct a model of graphene confined ultrathin layers of highly reactive metals, taking the synthetic highly reactive tin quantum sheets confined in graphene as an example. The higher electrochemical active area ensures 9 times larger carbon dioxide adsorption capacity relative to bulk tin, while the highly-conductive graphene favours rate-determining electron transfer from carbon dioxide to its radical anion. The lowered tin-tin coordination numbers, revealed by X-ray absorption fine structure spectroscopy, enable tin quantum sheets confined in graphene to efficiently stabilize the carbon dioxide radical anion, verified by 0.13 volts lowered potential of hydroxyl ion adsorption compared with bulk tin. Hence, the tin quantum sheets confined in graphene show enhanced electrocatalytic activity and stability. This work may provide a promising lead for designing efficient and robust catalysts for electrolytic fuel synthesis.

Enabling smart personalized healthcare: a hybrid mobile-cloud approach for ECG telemonitoring.

PubMed

Wang, Xiaoliang; Gui, Qiong; Liu, Bingwei; Jin, Zhanpeng; Chen, Yu

2014-05-01

The severe challenges of the skyrocketing healthcare expenditure and the fast aging population highlight the needs for innovative solutions supporting more accurate, affordable, flexible, and personalized medical diagnosis and treatment. Recent advances of mobile technologies have made mobile devices a promising tool to manage patients' own health status through services like telemedicine. However, the inherent limitations of mobile devices make them less effective in computation- or data-intensive tasks such as medical monitoring. In this study, we propose a new hybrid mobile-cloud computational solution to enable more effective personalized medical monitoring. To demonstrate the efficacy and efficiency of the proposed approach, we present a case study of mobile-cloud based electrocardiograph monitoring and analysis and develop a mobile-cloud prototype. The experimental results show that the proposed approach can significantly enhance the conventional mobile-based medical monitoring in terms of diagnostic accuracy, execution efficiency, and energy efficiency, and holds the potential in addressing future large-scale data analysis in personalized healthcare.

The nature of free-carrier transport in organometal halide perovskites

PubMed Central

Hakamata, Tomoya; Shimamura, Kohei; Shimojo, Fuyuki; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya

2016-01-01

Organometal halide perovskites are attracting great attention as promising material for solar cells because of their high power conversion efficiency. The high performance has been attributed to the existence of free charge carriers and their large diffusion lengths, but the nature of carrier transport at the atomistic level remains elusive. Here, nonadiabatic quantum molecular dynamics simulations elucidate the mechanisms underlying the excellent free-carrier transport in CH3NH3PbI3. Pb and I sublattices act as disjunct pathways for rapid and balanced transport of photoexcited electrons and holes, respectively, while minimizing efficiency-degrading charge recombination. On the other hand, CH3NH3 sublattice quickly screens out electrostatic electron-hole attraction to generate free carriers within 1 ps. Together this nano-architecture lets photoexcited electrons and holes dissociate instantaneously and travel far away to be harvested before dissipated as heat. This work provides much needed structure-property relationships and time-resolved information that potentially lead to rational design of efficient solar cells. PMID:26781627

Commercially Available Activated Carbon Fiber Felt Enables Efficient Solar Steam Generation.

PubMed

Li, Haoran; He, Yurong; Hu, Yanwei; Wang, Xinzhi

2018-03-21

Sun-driven steam generation is now possible and has the potential to help meet future energy needs. Current technologies often use solar condensers to increase solar irradiance. More recently, a technology for solar steam generation that uses heated surface water and low optical concentration is reported. In this work, a commercially available activated carbon fiber felt is used to generate steam efficiently under one sun illumination. The evaporation rate and solar conversion efficiency reach 1.22 kg m -2 h -1 and 79.4%, respectively. The local temperature of the evaporator with a floating activated carbon fiber felt reaches 48 °C. Apart from the high absorptivity (about 94%) of the material, the evaporation performance is enhanced thanks to the well-developed pores for improved water supply and steam escape and the low thermal conductivity, which enables reduced bulk water temperature increase. This study helps to find a promising material for solar steam generation using a water evaporator that can be produced economically (∼6 $/m 2 ) with long-term stability.

Novel concepts for low-cost and high-efficient thin film solar cells

NASA Astrophysics Data System (ADS)

Gómez, D.; Menéndez, A.; Sánchez, P.; Martínez, A.; Andrés, L. J.; Menéndez, M. F.; Campos, N.; García, A.; Sánchez, B.

2011-09-01

This work presents the activities carried out at ITMA Materials Technology related to the building integration of thin film (TF) photovoltaics (PV). Three different approaches have been developed in order to achieve high efficient solar cells at low manufacturing costs: (i) a new route for manufacturing monolithical silicon based thin film solar cells on building materials, (ii) the use of metallic nanoparticles for light trapping (plasmonic effects and light scattering) and (iii) the luminescent sol-gel coating on glass for solar concentration. In the first case, amorphous silicon modules (single junction) have been successfully manufactured at lab scale on steel and commercial ceramic substrates with efficiencies of 5.4% and 4.0%, respectively. Promising initial attempts have been also made in ethylene tetrafluoroethylene (ETFE), a polymer with high potential in textile architecture. In a similar way, the development of nanotechnology based coatings (metallic nanoparticles and luminescent materials) represent the most innovative part of the work and some preliminary results are showed.

Review of two-phase flow liquid metal MHD and turbine energy conversion concepts for space applications

NASA Technical Reports Server (NTRS)

Fabris, Gracio

1992-01-01

Two-phase energy conversion systems could be liquid metal magnetohydrodynamic (LMMHD) with no moving parts or two-phase turbines. Both of them are inherently simple and reliable devices which can operate in a wide range of temperatures. Their thermal efficiency is significantly higher than for conventional cycles due to reheat of vapor by liquid phase during the energy converting expansion. Often they can be more easily coupled to heat sources. These features make two-phase systems particularly promising for space application. Insufficient research has been done in the past. So far achieved LMMHD generator and two-phase turbine efficiencies are in the 40 to 45 percent range. However if certain fluid dynamic and design problems are resolved these efficiencies could be brought into the range of 70 percent. This would make two-phase systems extremely competitive as compared to present or other proposed conversion system for space. Accordingly, well directed research effort on potential space applications of two-phase conversion systems would be a wise investment.

Highly efficient preparation of sphingoid bases from glucosylceramides by chemoenzymatic method[S

PubMed Central

Gowda, Siddabasave Gowda B.; Usuki, Seigo; Hammam, Mostafa A. S.; Murai, Yuta; Igarashi, Yasuyuki; Monde, Kenji

2016-01-01

Sphingoid base derivatives have attracted increasing attention as promising chemotherapeutic candidates against lifestyle diseases such as diabetes and cancer. Natural sphingoid bases can be a potential resource instead of those derived by time-consuming total organic synthesis. In particular, glucosylceramides (GlcCers) in food plants are enriched sources of sphingoid bases, differing from those of animals. Several chemical methodologies to transform GlcCers to sphingoid bases have already investigated; however, these conventional methods using acid or alkaline hydrolysis are not efficient due to poor reaction yield, producing complex by-products and resulting in separation problems. In this study, an extremely efficient and practical chemoenzymatic transformation method has been developed using microwave-enhanced butanolysis of GlcCers and a large amount of readily available almond β-glucosidase for its deglycosylation reaction of lysoGlcCers. The method is superior to conventional acid/base hydrolysis methods in its rapidity and its reaction cleanness (no isomerization, no rearrangement) with excellent overall yield. PMID:26667669

One-pot green synthesis of doxorubicin loaded-silica nanoparticles for in vivo cancer therapy.

PubMed

Jiang, Shan; Hua, Li; Guo, Zilong; Sun, Lin

2018-09-01

The present work reveals a new and simple one-pot green method to load doxorubicin (DOX) drugs in silica nanoparticles for efficient in vivo cancer therapy. The synthesis of DOX loaded silica nanoparticles (SiNPs/DOX) is based on the efficient encapsulation of DOX in surfactant Tween 80 micelles which act as a template for the formation of silica nanoparticles. The release profile, cellular uptake behavior, cytotoxicity and antitumor effect of SiNPs/DOX nanoparticles were investigated and compared to free DOX. The silica nanoparticles improved the cellular drug delivery efficiency and exhibited high cytotoxicity, successfully achieving the inhibition of tumor growth. Notably, the tumor size and weight of SiNPs/DOX group was 2-fold and 1.7-fold smaller than that of free DOX group, and 4-fold and 2-fold smaller than that of PBS group. The one-pot green synthesis system may have the potential to be developed as a promising drug delivery system. Copyright © 2018 Elsevier B.V. All rights reserved.

Deep learning as a tool for increased accuracy and efficiency of histopathological diagnosis

NASA Astrophysics Data System (ADS)

Litjens, Geert; Sánchez, Clara I.; Timofeeva, Nadya; Hermsen, Meyke; Nagtegaal, Iris; Kovacs, Iringo; Hulsbergen-van de Kaa, Christina; Bult, Peter; van Ginneken, Bram; van der Laak, Jeroen

2016-05-01

Pathologists face a substantial increase in workload and complexity of histopathologic cancer diagnosis due to the advent of personalized medicine. Therefore, diagnostic protocols have to focus equally on efficiency and accuracy. In this paper we introduce ‘deep learning’ as a technique to improve the objectivity and efficiency of histopathologic slide analysis. Through two examples, prostate cancer identification in biopsy specimens and breast cancer metastasis detection in sentinel lymph nodes, we show the potential of this new methodology to reduce the workload for pathologists, while at the same time increasing objectivity of diagnoses. We found that all slides containing prostate cancer and micro- and macro-metastases of breast cancer could be identified automatically while 30-40% of the slides containing benign and normal tissue could be excluded without the use of any additional immunohistochemical markers or human intervention. We conclude that ‘deep learning’ holds great promise to improve the efficacy of prostate cancer diagnosis and breast cancer staging.

High-Efficiency and High-Color-Rendering-Index Semitransparent Polymer Solar Cells Induced by Photonic Crystals and Surface Plasmon Resonance.

PubMed

Shen, Ping; Wang, Guoxin; Kang, Bonan; Guo, Wenbin; Shen, Liang

2018-02-21

Semitransparent polymer solar cells (ST-PSCs) show attractive potential in power-generating windows or building-integrated photovoltaics. However, the development of ST-PSCs is lagging behind opaque PSCs because of the contradiction between device efficiency and transmission. Herein, Ag/Au alloy nanoparticles and photonic crystals (PCs) were simultaneously introduced into ST-PSCs, acting compatibly as localized surface plasmon resonances and distributed Bragg reflectors to enhance light absorption and transmission. As a result, ST-PSCs based on a hybrid PTB7-Th:PC 71 BM active layer contribute an efficiency as high as 7.13 ± 0.15% and an average visible transmission beyond 20%, which are superior to most of the reported results. Furthermore, PCs can partly compensate valley range of transmission by balancing reflection and transmission regions, yielding a high color rendering index of 95. We believe that the idea of two light management methods compatibly enhancing the performance of ST-PSCs can offer a promising path to develop photovoltaic applications.

Electrosynthesis of hydrogen peroxide via the reduction of oxygen assisted by power ultrasound.

PubMed

González-García, José; Banks, Craig E; Sljukić, Biljana; Compton, Richard G

2007-04-01

The electrosynthesis of hydrogen peroxide using the oxygen reduction reaction has been studied in the absence and presence of power ultrasound in a non-optimized sono-electrochemical flow reactor (20 cm cathodic compartment length with 6.5 cm inner diameter) with reticulated vitreous glassy carbon electrode (30 x 40 x 10 mm, 10 ppi, 7 cm(2)cm(-3)) as the cathode. The effect of several electrochemical operational variables (pH, volumetric flow, potential) and of the sono-electrochemical parameters (ultrasound amplitude and horn-to-electrode distance) on the cumulative concentration of hydrogen peroxide and current efficiency of the electrosynthesis process have been explored. The application of power ultrasound was found to increase both the cumulative concentration of hydrogen peroxide and the current efficiency. The application of ultrasound is therefore a promising approach to the increased efficiency of production of hydrogen peroxide by electrosynthesis, even in the solutions of lower pH (<12). The results demonstrate the feasibility of at-site-of-use green synthesis of hydrogen peroxide.

Ultrahigh Responsivity-Bandwidth Product in a Compact InP Nanopillar Phototransistor Directly Grown on Silicon

PubMed Central

Ko, Wai Son; Bhattacharya, Indrasen; Tran, Thai-Truong D.; Ng, Kar Wei; Adair Gerke, Stephen; Chang-Hasnain, Connie

2016-01-01

Highly sensitive and fast photodetectors can enable low power, high bandwidth on-chip optical interconnects for silicon integrated electronics. III-V compound semiconductor direct-bandgap materials with high absorption coefficients are particularly promising for photodetection in energy-efficient optical links because of the potential to scale down the absorber size, and the resulting capacitance and dark current, while maintaining high quantum efficiency. We demonstrate a compact bipolar junction phototransistor with a high current gain (53.6), bandwidth (7 GHz) and responsivity (9.5 A/W) using a single crystalline indium phosphide nanopillar directly grown on a silicon substrate. Transistor gain is obtained at sub-picowatt optical power and collector bias close to the CMOS line voltage. The quantum efficiency-bandwidth product of 105 GHz is the highest for photodetectors on silicon. The bipolar junction phototransistor combines the receiver front end circuit and absorber into a monolithic integrated device, eliminating the wire capacitance between the detector and first amplifier stage. PMID:27659796

White organic light-emitting diodes with fluorescent tube efficiency.

PubMed

Reineke, Sebastian; Lindner, Frank; Schwartz, Gregor; Seidler, Nico; Walzer, Karsten; Lüssem, Björn; Leo, Karl

2009-05-14

The development of white organic light-emitting diodes (OLEDs) holds great promise for the production of highly efficient large-area light sources. High internal quantum efficiencies for the conversion of electrical energy to light have been realized. Nevertheless, the overall device power efficiencies are still considerably below the 60-70 lumens per watt of fluorescent tubes, which is the current benchmark for novel light sources. Although some reports about highly power-efficient white OLEDs exist, details about structure and the measurement conditions of these structures have not been fully disclosed: the highest power efficiency reported in the scientific literature is 44 lm W(-1) (ref. 7). Here we report an improved OLED structure which reaches fluorescent tube efficiency. By combining a carefully chosen emitter layer with high-refractive-index substrates, and using a periodic outcoupling structure, we achieve a device power efficiency of 90 lm W(-1) at 1,000 candelas per square metre. This efficiency has the potential to be raised to 124 lm W(-1) if the light outcoupling can be further improved. Besides approaching internal quantum efficiency values of one, we have also focused on reducing energetic and ohmic losses that occur during electron-photon conversion. We anticipate that our results will be a starting point for further research, leading to white OLEDs having efficiencies beyond 100 lm W(-1). This could make white-light OLEDs, with their soft area light and high colour-rendering qualities, the light sources of choice for the future.

Novel sarsasapogenin-triazolyl hybrids as potential anti-Alzheimer's agents: Design, synthesis and biological evaluation.

PubMed

Wang, Wenbao; Wang, Wei; Yao, Guodong; Ren, Qiang; Wang, Di; Wang, Zedan; Liu, Peng; Gao, Pinyi; Zhang, Yan; Wang, Shaojie; Song, Shaojiang

2018-05-10

Sarsasapogenin, an active ingredient in Rhizoma anemarrhenae, is a promising bioactive lead compound in the treatment of Alzheimer's disease. To search for more efficient anti-Alzheimer agents, a series of novel sarsasapogenin-triazolyl hybrids were designed, synthesized, and evaluated for their Aβ 1-42 aggregation inhibitory activities. Most of these new hybrids displayed potent Aβ 1-42 aggregation inhibition. In particular, the promising compounds 6j and 6o displayed a better ability to interrupt the formation of Aβ 1-42 fibrils than curcumin. Moreover, 6j and 6o exhibited moderate neuroprotective effects against H 2 O 2 -induced neurotoxicity in SH-SY5Y cells. To investigate whether 6j and 6o could improve cognitive deficits, we performed behavioral tests to examine the learning and memory impairments induced by intracerebroventricular injection of Aβ 1-42 (ICV-Aβ 1-42 ) in mice and TUNEL staining to observe neuronal apoptosis in the hippocampus. The results obtained indicated that oral treatment with 6j and 6o significantly ameliorated cognitive impairments in behavioral tests and TUNEL staining showed that 6j and 6o attenuated neuronal loss in the brain. Taken together, the results we obtained showed that the sarsasapogenin skeleton could be a promising structural template for the development of new anti-Alzheimer drug candidates, and compounds 6j and 6o have the potential to be important lead compounds for further research. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Treating colon cancer with a suicide gene delivered by self-assembled cationic MPEG-PCL micelles

NASA Astrophysics Data System (ADS)

Duan, Xingmei; Wang, Pan; Men, Ke; Gao, Xiang; Huang, Meijuan; Gou, Maling; Chen, Lijuan; Qian, Zhiyong; Wei, Yuquan

2012-03-01

Biodegradable cationic micelles show promise for applications in gene delivery. In this article, we used DOTAP to modify monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL, MP) micelles in one step, creating novel cationic self-assembled DOTAP and MPEG-PCL hybrid micelles (DMP). These micelles had a mean particle size of 46 +/- 5.6 nm and a zeta potential of 41.8 +/- 0.5 mV, and had the capacity to bind DNA. Compared with PEI25K (the gold standard), DMP micelles had higher transfection efficiency and lower cytotoxicity. Moreover, we used DMP to deliver the Survivin-T34A gene (S-T34A, a suicide gene) to treat colon cancer. DMP delivered the Survivin-T34A gene (DMP/S-T34A) and could induce apoptosis in cancer cells, resulting in inhibition of the growth of C-26 colon cancer cells in vitro. An in vivo study indicated that intraperitoneal administration of DMP micelles delivered the Survivin-T34A gene and efficiently inhibited the growth of abdominal metastatic C-26 colon cancer and the malignant ascites. These data suggest that DMP may be a novel gene carrier, and its delivery of the S-T34A gene may have promising applications in the treatment of colon cancer.

Entropy-Based Search Algorithm for Experimental Design

NASA Astrophysics Data System (ADS)

Malakar, N. K.; Knuth, K. H.

2011-03-01

The scientific method relies on the iterated processes of inference and inquiry. The inference phase consists of selecting the most probable models based on the available data; whereas the inquiry phase consists of using what is known about the models to select the most relevant experiment. Optimizing inquiry involves searching the parameterized space of experiments to select the experiment that promises, on average, to be maximally informative. In the case where it is important to learn about each of the model parameters, the relevance of an experiment is quantified by Shannon entropy of the distribution of experimental outcomes predicted by a probable set of models. If the set of potential experiments is described by many parameters, we must search this high-dimensional entropy space. Brute force search methods will be slow and computationally expensive. We present an entropy-based search algorithm, called nested entropy sampling, to select the most informative experiment for efficient experimental design. This algorithm is inspired by Skilling's nested sampling algorithm used in inference and borrows the concept of a rising threshold while a set of experiment samples are maintained. We demonstrate that this algorithm not only selects highly relevant experiments, but also is more efficient than brute force search. Such entropic search techniques promise to greatly benefit autonomous experimental design.

An update on the clinical use of drug-coated balloons in percutaneous coronary interventions.

PubMed

Cheng, Yanping; Leon, Martin B; Granada, Juan F

2016-06-01

Drug-coated balloons (DCB) promise to deliver anti-proliferative drugs and prevent restenosis leaving nothing behind. Although, randomized clinical trials have demonstrated their efficacy for the treatment of in-stent restenosis, clinical evidence supporting their use in other coronary applications is still lacking. This review summarizes the development status of clinically available DCB technologies and provides an update on the current data for their coronary use. Current generation DCB prevent restenosis by delivering paclitaxel particles on the surface of the vessel wall. Although clinically available technologies share a common mechanism of action, important differences in pharmacokinetic behavior and safety profiles do exist. Future technological improvements include the development of coatings displaying: high transfer efficiency; low particle embolization potential; and alternative drug formulations. Optimized balloon-based delivery systems and drug encapsulation technologies also promise to improve the technical limitations of current generation DCB. Although proving clinical superiority against DES may prove to be difficult in mainstream applications (i.e., de novo), new generation DCB technologies have the potential to achieve a strong position in the interventional field in clinical settings in which the efficacy of DES use is not proven or justified (i.e., bifurcations).

High-rate capability of three-dimensionally ordered macroporous T-Nb2O5 through Li+ intercalation pseudocapacitance

NASA Astrophysics Data System (ADS)

Lou, Shuaifeng; Cheng, Xinqun; Wang, Long; Gao, Jinlong; Li, Qin; Ma, Yulin; Gao, Yunzhi; Zuo, Pengjian; Du, Chunyu; Yin, Geping

2017-09-01

Orthorhombic Niobium oxide (T-Nb2O5) has been regarded as a promising anode material for high-rate lithium ion batteries (LIBs) due to its potential to operate at high rates with improved safety and high theoretical capacity of 200 mA h g-1. Herein, three-dimensionally ordered macroporous (3DOM) T-Nb2O5, with mesoporous hierarchical structure, was firstly prepared by a simple approach employing self-assembly polystyrene (PS) microspheres as hard templates. The obtained T-Nb2O5 anode material presents obvious and highly-efficiency pseudocapacitive Li+ intercalation behaviour, which plays a dominant role in the kinetics of electrode process. As a result, rapid Li+ intercalation/de-intercalation are achieved, leading to excellent rate capability and long cycle life. The 3DOM T-Nb2O5 shows a remarkable high capacity of 106 and 77 mA h g-1 at the rate of 20C and 50C. The work presented herein holds great promise for future design of material structure, and demonstrates the great potential of T-Nb2O5 as a practical high-rate anode material for LIBs.

Homogeneous synthesis of quaternized chitin in NaOH/urea aqueous solution as a potential gene vector.

PubMed

Peng, Na; Ai, Ziye; Fang, Zehong; Wang, Yanfeng; Xia, Zhiping; Zhong, Zibiao; Fan, Xiaoli; Ye, Qifa

2016-10-05

Water-soluble quaternized chitins (QCs) were homogeneously synthesized by reacting chitin with (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) in 8wt% NaOH/4wt% urea aqueous solutions. The chemical structure and solution properties of the quaternized chitins were characterized by (1)H NMR, FT-IR, elemental analysis, dynamic light scattering (DLS) and zeta potential measurements. The results demonstrated that the water-soluble QCs, with a degree of substitution (DS) values of 0.27-0.54, could be obtained by varying the concentration of chitin, the molar ratio of CHPTAC to chitin unit, and the reaction time at room temperature (25°C). Two QCs (DS=0.36 and 0.54) were selected and studied as gene carriers. Agarose gel retardation assay revealed that both QCs could condense DNA efficiently when N/P ratio>3. The results of particle size and zeta potential indicated that both QCs had a good ability of condensing plasmid DNA into compact nanoparticles with the size of 100-200nm and zeta potential of +18 to +36mV. Compared to polyethylenimine (PEI, 25kDa), the QCs exhibited outstanding low cytotoxicity. Transfection efficiencies of the QCs/DNA complexes were measured using pGL-3 encoding luciferase as the foreign DNA, and the QCs/DNA complexes showed effective transfection efficiencies in 293T cells. These results revealed that the QCs prepared in NaOH/urea aqueous solutions could be used as promising non-viral gene carriers owing to their excellent characteristics. Copyright © 2016. Published by Elsevier Ltd.

Evaluation of high-perimeter electrode designs for deep brain stimulation

NASA Astrophysics Data System (ADS)

Howell, Bryan; Grill, Warren M.

2014-08-01

Objective. Deep brain stimulation (DBS) is an effective treatment for movement disorders and a promising therapy for treating epilepsy and psychiatric disorders. Despite its clinical success, complications including infections and mis-programing following surgical replacement of the battery-powered implantable pulse generator adversely impact the safety profile of this therapy. We sought to decrease power consumption and extend battery life by modifying the electrode geometry to increase stimulation efficiency. The specific goal of this study was to determine whether electrode contact perimeter or area had a greater effect on increasing stimulation efficiency. Approach. Finite-element method (FEM) models of eight prototype electrode designs were used to calculate the electrode access resistance, and the FEM models were coupled with cable models of passing axons to quantify stimulation efficiency. We also measured in vitro the electrical properties of the prototype electrode designs and measured in vivo the stimulation efficiency following acute implantation in anesthetized cats. Main results. Area had a greater effect than perimeter on altering the electrode access resistance; electrode (access or dynamic) resistance alone did not predict stimulation efficiency because efficiency was dependent on the shape of the potential distribution in the tissue; and, quantitative assessment of stimulation efficiency required consideration of the effects of the electrode-tissue interface impedance. Significance. These results advance understanding of the features of electrode geometry that are important for designing the next generation of efficient DBS electrodes.

Waveforms for optimal sub-keV high-order harmonics with synthesized two- or three-colour laser fields.

PubMed

Jin, Cheng; Wang, Guoli; Wei, Hui; Le, Anh-Thu; Lin, C D

2014-05-30

High-order harmonics extending to the X-ray region generated in a gas medium by intense lasers offer the potential for providing tabletop broadband light sources but so far are limited by their low conversion efficiency. Here we show that harmonics can be enhanced by one to two orders of magnitude without an increase in the total laser power if the laser's waveform is optimized by synthesizing two- or three-colour fields. The harmonics thus generated are also favourably phase-matched so that radiation is efficiently built up in the gas medium. Our results, combined with the emerging intense high-repetition MHz lasers, promise to increase harmonic yields by several orders to make harmonics feasible in the near future as general bright tabletop light sources, including intense attosecond pulses.

Quasi-continuous metasurface for ultra-broadband and polarization-controlled electromagnetic beam deflection.

PubMed

Wang, Yanqin; Pu, Mingbo; Zhang, Zuojun; Li, Xiong; Ma, Xiaoliang; Zhao, Zeyu; Luo, Xiangang

2015-12-04

Two-dimensional metasurface has attracted growing interest in recent years, owing to its ability in manipulating the phase, amplitude and polarization state of electromagnetic wave within a single interface. However, most existing metasurfaces rely on the collective responses of a set of discrete meta-atoms to perform various functionalities. In this paper, we presented a quasi-continuous metasurface for high-efficiency and broadband beam steering in the microwave regime. It is demonstrated both in simulation and experiment that the incident beam deviates from the normal direction after transmitting through the ultrathin metasurface. The efficiency of the proposed metasurface approximates to the theoretical limit of the single-layer metasurface in a broad frequency range, owing to the elimination of the circuit resonance in traditional discrete structures. The proposed scheme promises potential applications in broadband electromagnetic modulation and communication systems, etc.

Treatment of donor cell/embryo with different approaches to improve development after nuclear transfer.

PubMed

Mizutani, Eiji; Wakayama, Sayaka; Wakayama, Teruhiko

2015-01-01

The successful production of cloned animals by somatic cell nuclear transfer (SCNT) is a promising technology with many potential applications in basic research, medicine, and agriculture. However, the low efficiency and the difficulty of cloning are major obstacles to the widespread use of this technology. Since the first mammal cloned from an adult donor cell was born, many attempts have been made to improve animal cloning techniques, and some approaches have successfully improved its efficiency. Nuclear transfer itself is still difficult because it requires an accomplished operator with a practiced technique. Thus, it is very important to find simple and reproducible methods for improving the success rate of SCNT. In this chapter, we will review our recent protocols, which seem to be the simplest and most reliable method to date to improve development of SCNT embryos.

A Survey of Architectural Techniques for Near-Threshold Computing

DOE PAGES

Mittal, Sparsh

2015-12-28

Energy efficiency has now become the primary obstacle in scaling the performance of all classes of computing systems. In low-voltage computing and specifically, near-threshold voltage computing (NTC), which involves operating the transistor very close to and yet above its threshold voltage, holds the promise of providing many-fold improvement in energy efficiency. However, use of NTC also presents several challenges such as increased parametric variation, failure rate and performance loss etc. Our paper surveys several re- cent techniques which aim to offset these challenges for fully leveraging the potential of NTC. By classifying these techniques along several dimensions, we also highlightmore » their similarities and differences. Ultimately, we hope that this paper will provide insights into state-of-art NTC techniques to researchers and system-designers and inspire further research in this field.« less

A Survey of Architectural Techniques for Near-Threshold Computing

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

Mittal, Sparsh

Energy efficiency has now become the primary obstacle in scaling the performance of all classes of computing systems. In low-voltage computing and specifically, near-threshold voltage computing (NTC), which involves operating the transistor very close to and yet above its threshold voltage, holds the promise of providing many-fold improvement in energy efficiency. However, use of NTC also presents several challenges such as increased parametric variation, failure rate and performance loss etc. Our paper surveys several re- cent techniques which aim to offset these challenges for fully leveraging the potential of NTC. By classifying these techniques along several dimensions, we also highlightmore » their similarities and differences. Ultimately, we hope that this paper will provide insights into state-of-art NTC techniques to researchers and system-designers and inspire further research in this field.« less

Wavelength-tunable waveguides based on polycrystalline organic-inorganic perovskite microwires

NASA Astrophysics Data System (ADS)

Wang, Ziyu; Liu, Jingying; Xu, Zai-Quan; Xue, Yunzhou; Jiang, Liangcong; Song, Jingchao; Huang, Fuzhi; Wang, Yusheng; Zhong, Yu Lin; Zhang, Yupeng; Cheng, Yi-Bing; Bao, Qiaoliang

2016-03-01

Hybrid organic-inorganic perovskites have emerged as new photovoltaic materials with impressively high power conversion efficiency due to their high optical absorption coefficient and long charge carrier diffusion length. In addition to high photoluminescence quantum efficiency and chemical tunability, hybrid organic-inorganic perovskites also show intriguing potential for diverse photonic applications. In this work, we demonstrate that polycrystalline organic-inorganic perovskite microwires can function as active optical waveguides with small propagation loss. The successful production of high quality perovskite microwires with different halogen elements enables the guiding of light with different colours. Furthermore, it is interesting to find that out-coupled light intensity from the microwire can be effectively modulated by an external electric field, which behaves as an electro-optical modulator. This finding suggests the promising applications of perovskite microwires as effective building blocks in micro/nano scale photonic circuits.

Wavelength-tunable waveguides based on polycrystalline organic-inorganic perovskite microwires.

PubMed

Wang, Ziyu; Liu, Jingying; Xu, Zai-Quan; Xue, Yunzhou; Jiang, Liangcong; Song, Jingchao; Huang, Fuzhi; Wang, Yusheng; Zhong, Yu Lin; Zhang, Yupeng; Cheng, Yi-Bing; Bao, Qiaoliang

2016-03-28

Hybrid organic-inorganic perovskites have emerged as new photovoltaic materials with impressively high power conversion efficiency due to their high optical absorption coefficient and long charge carrier diffusion length. In addition to high photoluminescence quantum efficiency and chemical tunability, hybrid organic-inorganic perovskites also show intriguing potential for diverse photonic applications. In this work, we demonstrate that polycrystalline organic-inorganic perovskite microwires can function as active optical waveguides with small propagation loss. The successful production of high quality perovskite microwires with different halogen elements enables the guiding of light with different colours. Furthermore, it is interesting to find that out-coupled light intensity from the microwire can be effectively modulated by an external electric field, which behaves as an electro-optical modulator. This finding suggests the promising applications of perovskite microwires as effective building blocks in micro/nano scale photonic circuits.

Geraniol encapsulated in chitosan/gum arabic nanoparticles: a promising system for pest management in sustainable agriculture.

PubMed

de Oliveira, Jhones Luiz; Campos, Estefania Vangelie Ramos; Pereira, Anderson E S; Nunes, Lucas E S; da Silva, Camila C L; Pasquoto, Tatiane; Lima, Renata; Smaniotto, Giovani; Polanczyk, Ricardo Antonio; Fraceto, Leonardo F

2018-05-07

The nanoencapsulation of botanical compounds (such as geraniol) is an important strategy that can be used to increase the stability and efficiency of these substances in integrated pest management. In this study, chitosan/gum arabic nanoparticles containing geraniol were prepared and characterized. In addition, evaluation was made of the biological activity of geraniol encapsulated in chitosan/gum arabic nanoparticles towards whitefly (Bemisia tabaci). The optimized formulation showed a high encapsulation efficiency (>90%) and remained stable for about 120 days. The formulation protected the geraniol against degradation by UV radiation, and the in vitro release was according to a diffusion mechanism that was influenced by temperature. An attraction effect was observed for Bemisia tabaci, indicating the potential of this type of system for use in pest management, especially in trap devices.

Broadband and chiral binary dielectric meta-holograms.

PubMed

Khorasaninejad, Mohammadreza; Ambrosio, Antonio; Kanhaiya, Pritpal; Capasso, Federico

2016-05-01

Subwavelength structured surfaces, known as meta-surfaces, hold promise for future compact and optically thin devices with versatile functionalities. By revisiting the concept of detour phase, we demonstrate high-efficiency holograms with broadband and chiral imaging functionalities. In our devices, the apertures of binary holograms are replaced by subwavelength structured microgratings. We achieve broadband operation from the visible to the near infrared and efficiency as high as 75% in the 1.0 to 1.4 μm range by compensating for the inherent dispersion of the detour phase with that of the subwavelength structure. In addition, we demonstrate chiral holograms that project different images depending on the handedness of the reference beam by incorporating a geometric phase. Our devices' compactness, lightness, and ability to produce images even at large angles have significant potential for important emerging applications such as wearable optics.

Broadband and chiral binary dielectric meta-holograms

PubMed Central

Khorasaninejad, Mohammadreza; Ambrosio, Antonio; Kanhaiya, Pritpal; Capasso, Federico

2016-01-01

Subwavelength structured surfaces, known as meta-surfaces, hold promise for future compact and optically thin devices with versatile functionalities. By revisiting the concept of detour phase, we demonstrate high-efficiency holograms with broadband and chiral imaging functionalities. In our devices, the apertures of binary holograms are replaced by subwavelength structured microgratings. We achieve broadband operation from the visible to the near infrared and efficiency as high as 75% in the 1.0 to 1.4 μm range by compensating for the inherent dispersion of the detour phase with that of the subwavelength structure. In addition, we demonstrate chiral holograms that project different images depending on the handedness of the reference beam by incorporating a geometric phase. Our devices’ compactness, lightness, and ability to produce images even at large angles have significant potential for important emerging applications such as wearable optics. PMID:27386518

Multiple Exciton Generation in Colloidal Nanocrystals

PubMed Central

Smith, Charles; Binks, David

2013-01-01

In a conventional solar cell, the energy of an absorbed photon in excess of the band gap is rapidly lost as heat, and this is one of the main reasons that the theoretical efficiency is limited to ~33%. However, an alternative process, multiple exciton generation (MEG), can occur in colloidal quantum dots. Here, some or all of the excess energy is instead used to promote one or more additional electrons to the conduction band, potentially increasing the photocurrent of a solar cell and thereby its output efficiency. This review will describe the development of this field over the decade since the first experimental demonstration of multiple exciton generation, including the controversies over experimental artefacts, comparison with similar effects in bulk materials, and the underlying mechanisms. We will also describe the current state-of-the-art and outline promising directions for further development. PMID:28348283

Particle Engineering Via Mechanical Dry Coating in the Design of Pharmaceutical Solid Dosage Forms.

PubMed

Qu, Li; Morton, David A V; Zhou, Qi Tony

2015-01-01

Cohesive powders are problematic in the manufacturing of pharmaceutical solid dosage forms because they exhibit poor flowability, fluidization and aerosolization. These undesirable bulk properties of cohesive powders represent a fundamental challenge in the design of efficient pharmaceutical manufacturing processes. Recently, mechanical dry coating has attracted increasing attention as it can improve the bulk properties of cohesive powders in a cheaper, simpler, safer and more environment-friendly way than the existing solvent-based counterparts. In this review, mechanical dry coating techniques are outlined and their potential applications in formulation and manufacturing of pharmaceutical solid dosage forms are discussed. Reported data from the literature have shown that mechanical dry coating holds promise for the design of superior pharmaceutical solid formulations or manufacturing processes by engineering the interfaces of cohesive powders in an efficient and economical way.

In vivo toxicity, biodistribution, and clearance of glutathione-coated gold nanoparticles.

PubMed

Simpson, Carrie A; Salleng, Kenneth J; Cliffel, David E; Feldheim, Daniel L

2013-02-01

Gold nanoparticles are emerging as promising materials from which to construct nanoscale therapeutics and therapeutic delivery systems. However, animal studies have shown that gold nanoparticles modified with certain thiol monolayers such as tiopronin can cause renal complications and morbidity. Although these effects may be eliminated by coadsorbing small amounts of polyethylene glycol (PEG) onto the nanoparticle surface, PEG can also lower cellular internalization efficiency and binding interactions with protein disease targets, significantly reducing the potential for using gold nanoparticles as therapeutics. Using ICP-MS analysis of blood, urine, and several organs, we show in this article that glutathione-coated gold nanoparticles (1.2 nm ± 0.9 nm) cause no morbidity at any concentration up to and including 60 μM and target primary organs although providing gradual dissipation and clearance over time. This study suggests that glutathione may be an attractive alternative to PEG in the design of gold nanoparticle therapeutics. This study describes the utility and toxicity of glutathione coated gold nanoparticles in comparison to PEGylated counterparts that are commonly used to increase "Stealth" properties and lower cytotoxicity. Too much PEG on the NPs can lead to lower cellular internalization efficiency and less efficient binding interactions with protein disease targets, significantly reducing the potential for using gold nanoparticles as therapeutics. Copyright © 2013 Elsevier Inc. All rights reserved.

Development and in vivo evaluation of self-microemulsion as delivery system for α-mangostin.

PubMed

Xu, Wen-Ke; Jiang, Hui; Yang, Kui; Wang, Ya-Qin; Zhang, Qian; Zuo, Jian

2017-03-01

α-Mangostin (MG) is a versatile bioactive compound isolated from mangosteen and possesses significant pharmacokinetic shortages. To augment the potential clinical efficacy, MG-loaded self-microemulsion (MG-SME) was designed and prepared in this study, and its potential as a drug loading system was evaluated based on the pharmacokinetic performance and tissue distribution feature. The formula of MG-SME was optimized by an orthogonal test under the guidance of ternary phase diagram, and the prepared MG-SME was characterized by encapsulation efficiency, size distribution, and morphology. Optimized high performance liquid chromatography method was employed to determine concentrations of MG and characterize the pharmacokinetic and tissue distribution features of MG in rodents. It was found that diluted MG-SME was characterized as spherical particles with a mean diameter of 24.6 nm and an encapsulation efficiency of 87.26%. The delivery system enhanced the area under the curve of MG by 4.75 times and increased the distribution in lymphatic organs. These findings suggested that SME as a nano-sized delivery system efficiently promoted the digestive tract absorption of MG and modified its distribution in tissues. The targeting feature and high oral bioavailability of MG-SME promised a good clinical efficacy, especially for immune diseases. Copyright © 2017. Published by Elsevier Taiwan.

Dense image registration through MRFs and efficient linear programming.

PubMed

Glocker, Ben; Komodakis, Nikos; Tziritas, Georgios; Navab, Nassir; Paragios, Nikos

2008-12-01

In this paper, we introduce a novel and efficient approach to dense image registration, which does not require a derivative of the employed cost function. In such a context, the registration problem is formulated using a discrete Markov random field objective function. First, towards dimensionality reduction on the variables we assume that the dense deformation field can be expressed using a small number of control points (registration grid) and an interpolation strategy. Then, the registration cost is expressed using a discrete sum over image costs (using an arbitrary similarity measure) projected on the control points, and a smoothness term that penalizes local deviations on the deformation field according to a neighborhood system on the grid. Towards a discrete approach, the search space is quantized resulting in a fully discrete model. In order to account for large deformations and produce results on a high resolution level, a multi-scale incremental approach is considered where the optimal solution is iteratively updated. This is done through successive morphings of the source towards the target image. Efficient linear programming using the primal dual principles is considered to recover the lowest potential of the cost function. Very promising results using synthetic data with known deformations and real data demonstrate the potentials of our approach.

High-Efficiency Flexible Solar Cells Based on Organometal Halide Perovskites.

PubMed

Wang, Yuming; Bai, Sai; Cheng, Lu; Wang, Nana; Wang, Jianpu; Gao, Feng; Huang, Wei

2016-06-01

Flexible and light-weight solar cells are important because they not only supply power to wearable and portable devices, but also reduce the transportation and installation cost of solar panels. High-efficiency organometal halide perovskite solar cells can be fabricated by a low-temperature solution process, and hence are promising for flexible-solar-cell applications. Here, the development of perovskite solar cells is briefly discussed, followed by the merits of organometal halide perovskites as promising candidates as high-efficiency, flexible, and light-weight photovoltaic materials. Afterward, recent developments of flexible solar cells based on perovskites are reviewed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Techno-economic projections for advanced small solar thermal electric power plants to years 1990-2000

NASA Technical Reports Server (NTRS)

Fujita, T.; Manvi, R.; Roschke, E. J.; El-Gabalawi, N.; Herrera, G.; Kuo, T. J.; Chen, K. H.

1979-01-01

Advanced technologies applicable to solar thermal electric power systems in the 1990-200 time-frame are delineated for power applications that fulfill a wide spectrum of small power needs with primary emphasis on power ratings less than 10MWe. Projections of power system characteristics (energy and capital costs as a function of capacity factor) are made based on development of identified promising technologies and are used as the basis for comparing technology development options and combinations of these options to determine developmental directions offering potential for significant improvements. Stirling engines, Brayton/Rankine combined cycles and storage/transport concepts encompassing liquid metals, and reversible-reaction chemical systems are considered for two-axis tracking systems such as the central receiver or power tower concept and distributed parabolic dish receivers which can provide efficient low-cost solar energy collection while achieving high temperatures for efficient energy conversion. Pursuit of advanced technology across a broad front can result in post-1985 solar thermal systems having the potential of approaching the goal of competitiveness with conventional power systems.

Embedded vertically aligned cadmium telluride nanorod arrays grown by one-step electrodeposition for enhanced energy conversion efficiency in three-dimensional nanostructured solar cells.

PubMed

Wang, Jun; Liu, Shurong; Mu, Yannan; Liu, Li; A, Runa; Yang, Jiandong; Zhu, Guijie; Meng, Xianwei; Fu, Wuyou; Yang, Haibin

2017-11-01

Vertically aligned CdTe nanorods (NRs) arrays are successfully grown by a simple one-step and template-free electrodeposition method, and then embedded in the CdS window layer to form a novel three-dimensional (3D) heterostructure on flexible substrates. The parameters of electrodeposition such as deposition potential and pH of the solution are varied to analyze their important role in the formation of high quality CdTe NRs arrays. The photovoltaic conversion efficiency of the solar cell based on the 3D heterojunction structure is studied in detail. In comparison with the standard planar heterojunction solar cell, the 3D heterojunction solar cell exhibits better photovoltaic performance, which can be attributed to its enhanced optical absorption ability, increased heterojunction area and improved charge carrier transport. The better photoelectric property of the 3D heterojunction solar cell suggests great application potential in thin film solar cells, and the simple electrodeposition process represents a promising technique for large-scale fabrication of other nanostructured solar energy conversion devices. Copyright © 2017 Elsevier Inc. All rights reserved.

Site-Selective RNA Splicing Nanozyme: DNAzyme and RtcB Conjugates on a Gold Nanoparticle.

PubMed

Petree, Jessica R; Yehl, Kevin; Galior, Kornelia; Glazier, Roxanne; Deal, Brendan; Salaita, Khalid

2018-01-19

Modifying RNA through either splicing or editing is a fundamental biological process for creating protein diversity from the same genetic code. Developing novel chemical biology tools for RNA editing has potential to transiently edit genes and to provide a better understanding of RNA biochemistry. Current techniques used to modify RNA include the use of ribozymes, adenosine deaminase, and tRNA endonucleases. Herein, we report a nanozyme that is capable of splicing virtually any RNA stem-loop. This nanozyme is comprised of a gold nanoparticle functionalized with three enzymes: two catalytic DNA strands with ribonuclease function and an RNA ligase. The nanozyme cleaves and then ligates RNA targets, performing a splicing reaction that is akin to the function of the spliceosome. Our results show that the three-enzyme reaction can remove a 19 nt segment from a 67 nt RNA loop with up to 66% efficiency. The complete nanozyme can perform the same splice reaction at 10% efficiency. These splicing nanozymes represent a new promising approach for gene manipulation that has potential for applications in living cells.

Solid-State Thermionic Nuclear Power for Megawatt Propulsion, Planetary Surface and Commercial Power Project

NASA Technical Reports Server (NTRS)

George, Jeffrey

2014-01-01

Thermionic (TI) power conversion is a promising technology first investigated for power conversion in the 1960's, and of renewed interest due to modern advances in nanotechnology, MEMS, materials and manufacturing. Benefits include high conversion efficiency (20%), static operation with no moving parts and potential for high reliability, greatly reduced plant complexity, and the potential for reduced development costs. Thermionic emission, credited to Edison in 1880, forms the basis of vacuum tubes and much of 20th century electronics. Heat can be converted into electricity when electrons emitted from a hot surface are collected across a small gap. For example, two "small" (6 kWe) Thermionic Space Reactors were flown by the USSR in 1987-88 for ocean radar reconnaissance. Higher powered Nuclear-Thermionic power systems driving Electric Propulsion (Q-thruster, VASIMR, etc.) may offer the breakthrough necessary for human Mars missions of < 1 yr round trip. Power generation on Earth could benefit from simpler, moe economical nuclear plants, and "topping" of more fuel and emission efficient fossil-fuel plants.

Synthesis and characterization of N-(2-hydroxy)propyl-3-trimethyl ammonium chitosan chloride for potential application in gene delivery.

PubMed

Xiao, Bo; Wan, Ying; Wang, Xiaoyu; Zha, Qichen; Liu, Haoming; Qiu, Zhiye; Zhang, Shengmin

2012-03-01

A series of N-(2-hydroxy)propyl-3-trimethyl ammonium chitosan chloride (HTCC) samples with various degrees of quaternization ranging from 12.4 to 43.7% was synthesized. The structures and properties of HTCC were investigated by FT-IR, (1)H NMR, conductometric titration and XRD analysis. It was found that HTCC had a more amorphous structure than chitosan. HTCC samples showed significantly lower cytotoxicity than polyethyleneimine in HepG2 and HeLa cell lines. The samples spontaneously formed complexes with pGL3 luciferase plasmid. These complexes had desirable particle sizes (160-300 nm) and zeta potentials (10.8-18.7 mV) when the weight ratios of HTCC to plasmid altered in the range of 3:1-20:1. In vitro gene transfection results indicated that HTCC had significantly high transfection efficiency compared with chitosan for delivering pGL3 luciferase plasmid to HeLa cells. The results suggest that HTCC could be a promising non-viral vector for safe and efficient DNA delivery. Copyright © 2011 Elsevier B.V. All rights reserved.

Universal electrode interface for electrocatalytic oxidation of liquid fuels.

PubMed

Liao, Hualing; Qiu, Zhipeng; Wan, Qijin; Wang, Zhijie; Liu, Yi; Yang, Nianjun

2014-10-22

Electrocatalytic oxidations of liquid fuels from alcohols, carboxylic acids, and aldehydes were realized on a universal electrode interface. Such an interface was fabricated using carbon nanotubes (CNTs) as the catalyst support and palladium nanoparticles (Pd NPs) as the electrocatalysts. The Pd NPs/CNTs nanocomposite was synthesized using the ethylene glycol reduction method. It was characterized using transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, voltammetry, and impedance. On the Pd NPs/CNTs nanocomposite coated electrode, the oxidations of those liquid fuels occur similarly in two steps: the oxidations of freshly chemisorbed species in the forward (positive-potential) scan and then, in the reverse scan (negative-potential), the oxidations of the incompletely oxidized carbonaceous species formed during the forward scan. The oxidation charges were adopted to study their oxidation mechanisms and oxidation efficiencies. The oxidation efficiency follows the order of aldehyde (formaldehyde) > carboxylic acid (formic acid) > alcohols (ethanol > methanol > glycol > propanol). Such a Pd NPs/CNTs nanocomposite coated electrode is thus promising to be applied as the anode for the facilitation of direct fuel cells.

Influence of cationic lipid concentration on properties of lipid-polymer hybrid nanospheres for gene delivery.

PubMed

Bose, Rajendran J C; Arai, Yoshie; Ahn, Jong Chan; Park, Hansoo; Lee, Soo-Hong

2015-01-01

Nanoparticles have been widely used for nonviral gene delivery. Recently, cationic hybrid nanoparticles consisting of two different materials were suggested as a promising delivery vehicle. In this study, nanospheres with a poly(D,L-lactic-co-glycolic acid) (PLGA) core and cationic lipid shell were prepared, and the effect of cationic lipid concentrations on the properties of lipid polymer hybrid nanocarriers investigated. Lipid-polymer hybrid nanospheres (LPHNSs) were fabricated by the emulsion-solvent evaporation method using different concentrations of cationic lipids and characterized for size, surface charge, stability, plasmid DNA-binding capacity, cytotoxicity, and transfection efficiency. All LPHNSs had narrow size distribution with positive surface charges (ζ-potential 52-60 mV), and showed excellent plasmid DNA-binding capacity. In vitro cytotoxicity measurements with HEK293T, HeLa, HaCaT, and HepG2 cells also showed that LPHNSs exhibited less cytotoxicity than conventional transfection agents, such as Lipofectamine and polyethyleneimine-PLGA. As cationic lipid concentrations increased, the particle size of LPHNSs decreased while their ζ-potential increased. In addition, the in vitro transfection efficiency of LPHNSs increased as lipid concentration increased.

Enhancing light absorption within the carrier transport length in quantum junction solar cells.

PubMed

Fu, Yulan; Hara, Yukihiro; Miller, Christopher W; Lopez, Rene

2015-09-10

Colloidal quantum dot (CQD) solar cells have attracted tremendous attention because of their tunable absorption spectrum window and potentially low processing cost. Recently reported quantum junction solar cells represent a promising approach to building a rectifying photovoltaic device that employs CQD layers on each side of the p-n junction. However, the ultimate efficiency of CQD solar cells is still highly limited by their high trap state density in both p- and n-type CQDs. By modeling photonic structures to enhance the light absorption within the carrier transport length and by ensuring that the carrier generation and collection efficiencies were both augmented, our work shows that overall device current density could be improved. We utilized a two-dimensional numerical model to calculate the characteristics of patterned CQD solar cells based on a simple grating structure. Our calculation predicts a short circuit current density as high as 31  mA/cm², a value nearly 1.5 times larger than that of the conventional flat design, showing the great potential value of patterned quantum junction solar cells.

Ceramic nanocarriers: versatile nanosystem for protein and peptide delivery.

PubMed

Singh, Deependra; Dubey, Pooja; Pradhan, Madhulika; Singh, Manju Rawat

2013-02-01

Proteins and peptides have been established to be the potential drug candidate for various human diseases. But, delivery of these therapeutic protein and peptides is still a challenge due to their several unfavorable properties. Nanotechnology is expanding as a promising tool for the efficient delivery of proteins and peptides. Among numerous nano-based carriers, ceramic nanoparticles have proven themselves as a unique carrier for protein and peptide delivery as they provide a more stable, bioavailable, readily manufacturable, and acceptable proteins and polypeptide formulation. This article provides an overview of the various aspects of ceramic nanoparticles including their classification, methods of preparation, latest advances, and applications as protein and peptide delivery carriers. Ceramic nanocarriers seem to have potential for preserving structural integrity of proteins and peptides, thereby promoting a better therapeutic effect. This approach thus provides pharmaceutical scientists with a new hope for the delivery of proteins and peptides. Still, considerable study on ceramic nanocarrier is necessary with respect to pharmacokinetics, toxicology, and animal studies to confirm their efficiency as well as safety and to establish their clinical usefulness and scale-up to industrial level.

Mission Assessment of the Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)

NASA Technical Reports Server (NTRS)

Dankanich, John W.; Polzin, Kurt A.

2008-01-01

Pulsed inductive thrusters have typically been considered for future, high-power, missions requiring nuclear electric propulsion. These high-power systems, while promising equivalent or improved performance over state-of-the-art propulsion systems, presently have no planned missions for which they are well suited. The ability to efficiently operate an inductive thruster at lower energy and power levels may provide inductive thrusters near term applicability and mission pull. The Faraday Accelerator with Radio-frequency Assisted Discharge concept demonstrated potential for a high-efficiency, low-energy pulsed inductive thruster. The added benefits of energy recapture and/or pulse compression are shown to enhance the performance of the pulsed inductive propulsion system, yielding a system that con compete with and potentially outperform current state-of-the-art electric propulsion technologies. These enhancements lead to mission-level benefits associated with the use of a pulsed inductive thruster. Analyses of low-power near to mid-term missions and higher power far-term missions are undertaken to compare the performance of pulsed inductive thrusters with that delivered by state-of-the-art and development-level electric propulsion systems.

Rationales and Approaches for Studying Metabolism in Eukaryotic Microalgae

PubMed Central

Veyel, Daniel; Erban, Alexander; Fehrle, Ines; Kopka, Joachim; Schroda, Michael

2014-01-01

The generation of efficient production strains is essential for the use of eukaryotic microalgae for biofuel production. Systems biology approaches including metabolite profiling on promising microalgal strains, will provide a better understanding of their metabolic networks, which is crucial for metabolic engineering efforts. Chlamydomonas reinhardtii represents a suited model system for this purpose. We give an overview to genetically amenable microalgal strains with the potential for biofuel production and provide a critical review of currently used protocols for metabolite profiling on Chlamydomonas. We provide our own experimental data to underpin the validity of the conclusions drawn. PMID:24957022

(188)Re-SSS/Lipiodol: Development of a Potential Treatment for HCC from Bench to Bedside.

PubMed

Lepareur, Nicolas; Ardisson, Valérie; Noiret, Nicolas; Garin, Etienne

2012-01-01

Hepatocellular carcinoma (HCC) is the 5th most common tumour worldwide and has a dark prognosis. For nonoperable cases, metabolic radiotherapy with Lipiodol labelled with β-emitters is a promising therapeutic option. The Comprehensive Cancer Centre Eugène Marquis and the National Graduate School of Chemistry of Rennes (ENSCR) have jointly developed a stable and efficient labelling of Lipiodol with rhenium-188 (E(βmax) = 2.1 MeV) for the treatment of HCC. The major "milestones" of this development, from the first syntheses to the recent first injection in man, are described.

Perspective: Rapid synthesis of complex oxides by combinatorial molecular beam epitaxy

DOE PAGES

A. T. Bollinger; Wu, J.; Bozovic, I.

2016-03-15

In this study, the molecular beam epitaxy(MBE) technique is well known for producing atomically smooth thin films as well as impeccable interfaces in multilayers of many different materials. In particular, molecular beam epitaxy is well suited to the growth of complex oxides, materials that hold promise for many applications. Rapid synthesis and high throughput characterization techniques are needed to tap into that potential most efficiently. We discuss our approach to doing that, leaving behind the traditional one-growth-one-compound scheme and instead implementing combinatorial oxide molecular beam epitaxy in a custom built system.

Visible-to-telecom quantum frequency conversion of light from a single quantum emitter.

PubMed

Zaske, Sebastian; Lenhard, Andreas; Keßler, Christian A; Kettler, Jan; Hepp, Christian; Arend, Carsten; Albrecht, Roland; Schulz, Wolfgang-Michael; Jetter, Michael; Michler, Peter; Becher, Christoph

2012-10-05

We demonstrate efficient (>30%) quantum frequency conversion of visible single photons (711 nm) emitted by a quantum dot to a telecom wavelength (1313 nm). Analysis of the first- and second-order coherence before and after wavelength conversion clearly proves that pivotal properties, such as the coherence time and photon antibunching, are fully conserved during the frequency translation process. Our findings underline the great potential of single photon sources on demand in combination with quantum frequency conversion as a promising technique that may pave the way for a number of new applications in quantum technology.

Status of the advanced Stirling conversion system project for 25 kW dish Stirling applications

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Schreiber, Jeffrey G.

1991-01-01

Heat engines were evaluated for terrestrial Solar Distributed Heat Receivers. The Stirling engine was identified as one of the most promising heat engines for terrestrial applications. Technology development is also conducted for Stirling convertors directed toward a dynamic power source for space applications. Space power requirements include high reliability with very long life, low vibration, and high system efficiency. The free-piston Stirling engine has the potential for future high power space conversion systems, either nuclear or solar powered. Although both applications appear to be quite different, their requirements complement each other.

Microdosing: Concept, Application and Relevance

PubMed Central

Tewari, Tushar; Mukherjee, Shoibal

2010-01-01

The use of microdose pharmacokinetic studies as an essential tool in drug development is still to catch on. While this approach promises potential cost savings and a quantum leap in efficiencies of the drug development process, major hurdles still need to be overcome before the technique becomes commonplace and part of routine practice. Clear regulations in Europe and the USA have had an enabling effect. The lack of enabling provisions for microdosing studies in Indian regulation, despite low risk and manifest relevance for the local drug development industry, is inconsistent with the country's aspirations to be among the leaders in pharmaceutical research. PMID:21829784

Microdosing: concept, application and relevance.

PubMed

Tewari, Tushar; Mukherjee, Shoibal

2010-04-01

The use of microdose pharmacokinetic studies as an essential tool in drug development is still to catch on. While this approach promises potential cost savings and a quantum leap in efficiencies of the drug development process, major hurdles still need to be overcome before the technique becomes commonplace and part of routine practice. Clear regulations in Europe and the USA have had an enabling effect. The lack of enabling provisions for microdosing studies in Indian regulation, despite low risk and manifest relevance for the local drug development industry, is inconsistent with the country's aspirations to be among the leaders in pharmaceutical research.

On the possibility of singlet fission in crystalline quaterrylene

NASA Astrophysics Data System (ADS)

Wang, Xiaopeng; Liu, Xingyu; Cook, Cameron; Schatschneider, Bohdan; Marom, Noa

2018-05-01

Singlet fission (SF), the spontaneous down-conversion of a singlet exciton into two triplet excitons residing on neighboring molecules, is a promising route to improve organic photovoltaic (OPV) device efficiencies by harvesting two charge carriers from one photon. However, only a few materials have been discovered that exhibit intermolecular SF in the solid state, most of which are acene derivatives. Recently, there has been a growing interest in rylenes as potential SF materials. We use many-body perturbation theory in the GW approximation and the Bethe-Salpeter equation to investigate the possibility of intermolecular SF in crystalline perylene and quaterrylene. A new method is presented for determining the percent charge transfer (%CT) character of an exciton wave-function from double-Bader analysis. This enables relating exciton probability distributions to crystal packing. Based on comparison to known and predicted SF materials with respect to the energy conservation criterion (ES-2ET) and %CT, crystalline quaterrylene is a promising candidate for intermolecular SF. Furthermore, quaterrylene is attractive for OPV applications, thanks to its high stability and narrow optical gap. Perylene is not expected to exhibit SF; however, it is a promising candidate for harvesting sub-gap photons by triplet-triplet annihilation.

On the possibility of singlet fission in crystalline quaterrylene.

PubMed

Wang, Xiaopeng; Liu, Xingyu; Cook, Cameron; Schatschneider, Bohdan; Marom, Noa

2018-05-14

Singlet fission (SF), the spontaneous down-conversion of a singlet exciton into two triplet excitons residing on neighboring molecules, is a promising route to improve organic photovoltaic (OPV) device efficiencies by harvesting two charge carriers from one photon. However, only a few materials have been discovered that exhibit intermolecular SF in the solid state, most of which are acene derivatives. Recently, there has been a growing interest in rylenes as potential SF materials. We use many-body perturbation theory in the GW approximation and the Bethe-Salpeter equation to investigate the possibility of intermolecular SF in crystalline perylene and quaterrylene. A new method is presented for determining the percent charge transfer (%CT) character of an exciton wave-function from double-Bader analysis. This enables relating exciton probability distributions to crystal packing. Based on comparison to known and predicted SF materials with respect to the energy conservation criterion (E S -2E T ) and %CT, crystalline quaterrylene is a promising candidate for intermolecular SF. Furthermore, quaterrylene is attractive for OPV applications, thanks to its high stability and narrow optical gap. Perylene is not expected to exhibit SF; however, it is a promising candidate for harvesting sub-gap photons by triplet-triplet annihilation.

Chem/bio sensing with non-classical light and integrated photonics.

PubMed

Haas, J; Schwartz, M; Rengstl, U; Jetter, M; Michler, P; Mizaikoff, B

2018-01-29

Modern quantum technology currently experiences extensive advances in applicability in communications, cryptography, computing, metrology and lithography. Harnessing this technology platform for chem/bio sensing scenarios is an appealing opportunity enabling ultra-sensitive detection schemes. This is further facilliated by the progress in fabrication, miniaturization and integration of visible and infrared quantum photonics. Especially, the combination of efficient single-photon sources together with waveguiding/sensing structures, serving as active optical transducer, as well as advanced detector materials is promising integrated quantum photonic chem/bio sensors. Besides the intrinsic molecular selectivity and non-destructive character of visible and infrared light based sensing schemes, chem/bio sensors taking advantage of non-classical light sources promise sensitivities beyond the standard quantum limit. In the present review, recent achievements towards on-chip chem/bio quantum photonic sensing platforms based on N00N states are discussed along with appropriate recognition chemistries, facilitating the detection of relevant (bio)analytes at ultra-trace concentration levels. After evaluating recent developments in this field, a perspective for a potentially promising sensor testbed is discussed for reaching integrated quantum sensing with two fiber-coupled GaAs chips together with semiconductor quantum dots serving as single-photon sources.

In vitro immunotoxicity assessment of culture-derived extracellular vesicles in human monocytes

PubMed Central

Rosas, Lucia E.; Elgamal, Ola A.; Mo, Xiaokui; Phelps, Mitch A.; Schmittgen, Thomas D.; Papenfuss, Tracey L.

2016-01-01

The potential to engineer extracellular vesicles (EV) that target specific cells and deliver a therapeutic payload has propelled a growing interest in their development as promising therapeutics. These EV are often produced from cultured cells. Very little is known about the interaction of cell culture-derived EV with cells of the immune system and their potential immunomodulatory effects. The present study evaluated potential immunotoxic effects of HEK293T-derived EV on the human monocytic cell lines THP-1 and U937. Incubation of cells with different doses of EV for 16–24 h was followed by assessment of cytotoxicity and cell function by flow cytometry. Changes in cell functionality were evaluated by the capacity of cells to phagocytize fluorescent microspheres. In addition, the internalization of labeled EV in THP-1 and U937 cells was evaluated. Exposure to EV did not affect the viability of THP-1 or U937 cells. Although lower doses of the EV increased phagocytic capacity in both cell lines, phagocytic efficiency of individual cells was not affected by EV exposure at any of the doses evaluated. This study also demonstrated that THP-1 and U937 monocytic cells are highly permissive to EV entry in a dose-response manner. These results suggest that, although HEK293T-derived EV are efficiently internalized by human monocytic cells, they do not exert a cytotoxic effect or alter phagocytic efficiency on the cell lines evaluated. PMID:27075513

Arbuscular mycorrhizal association enhances drought tolerance potential of promising bioenergy grass (Saccharum arundinaceum retz.).

PubMed

Mirshad, P P; Puthur, Jos T

2016-07-01

The influence of arbuscular mycorrhizal fungi (AMF) (Glomus spp.) on some physiological and biochemical characteristics of bioenergy grass Saccharum arundinaceum subjected to drought stress was studied. The symbiotic association of Glomus spp. was established with S. arundinaceum, a potential bioenergy grass as evident from the increase in percentage of root infection and distribution frequency of vesicles when compared with non-arbuscular mycorrhizal plants. AMF-treated plants exhibited an enhanced accumulation of osmolytes such as sugars and proline and also increased protein content under drought. AMF association significantly increased the accumulation of non-enzymatic antioxidants like phenols, ascorbate and glutathione as well as enhanced the activities of antioxidant enzymes such as SOD (superoxide dismutase), APX (ascorbate peroxidase) and GPX (guaiacol peroxidase) resulting in reduced lipid peroxidation in S. arundinaceum. AMF symbiosis also ameliorated the drought-induced reduction of total chlorophyll content and activities of photosystem I and II. The maximum quantum efficiency of PS II (F v/F m) and potential photochemical efficiency (F v/F o) were higher in AMF plants as compared to non-AMF plants under drought stress. These results indicate that AMF association alleviate drought stress in S. arundinaceum by the accumulation of osmolytes and non-enzymatic antioxidants and enhanced activities of antioxidant enzymes, and hence, the photosynthetic efficiency is improved resulting in increased biomass production. AMF association with energy grasses also improves the acclimatization of S. arundinaceum for growing in marginal lands of drought-affected soils.

Accurate complex scaling of three dimensional numerical potentials

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

Cerioni, Alessandro; Genovese, Luigi; Duchemin, Ivan

2013-05-28

The complex scaling method, which consists in continuing spatial coordinates into the complex plane, is a well-established method that allows to compute resonant eigenfunctions of the time-independent Schroedinger operator. Whenever it is desirable to apply the complex scaling to investigate resonances in physical systems defined on numerical discrete grids, the most direct approach relies on the application of a similarity transformation to the original, unscaled Hamiltonian. We show that such an approach can be conveniently implemented in the Daubechies wavelet basis set, featuring a very promising level of generality, high accuracy, and no need for artificial convergence parameters. Complex scalingmore » of three dimensional numerical potentials can be efficiently and accurately performed. By carrying out an illustrative resonant state computation in the case of a one-dimensional model potential, we then show that our wavelet-based approach may disclose new exciting opportunities in the field of computational non-Hermitian quantum mechanics.« less

Geothermal energy from deep sedimentary basins: The Valley of Mexico (Central Mexico)

NASA Astrophysics Data System (ADS)

Lenhardt, Nils; Götz, Annette E.

2015-04-01

The geothermal potential of the Valley of Mexico has not been addressed in the past, although volcaniclastic settings in other parts of the world contain promising target reservoir formations. A first assessment of the geothermal potential of the Valley of Mexico is based on thermophysical data gained from outcrop analogues, covering all lithofacies types, and evaluation of groundwater temperature and heat flow values from literature. Furthermore, the volumetric approach of Muffler and Cataldi (1978) leads to a first estimation of ca. 4000 TWh (14.4 EJ) of power generation from Neogene volcanic rocks within the Valley of Mexico. Comparison with data from other sedimentary basins where deep geothermal reservoirs are identified shows the high potential of the Valley of Mexico for future geothermal reservoir utilization. The mainly low permeable lithotypes may be operated as stimulated systems, depending on the fracture porosity in the deeper subsurface. In some areas also auto-convective thermal water circulation might be expected and direct heat use without artificial stimulation becomes reasonable. Thermophysical properties of tuffs and siliciclastic rocks qualify them as promising target horizons (Lenhardt and Götz, 2015). The here presented data serve to identify exploration areas and are valuable attributes for reservoir modelling, contributing to (1) a reliable reservoir prognosis, (2) the decision of potential reservoir stimulation, and (3) the planning of long-term efficient reservoir utilization. References Lenhardt, N., Götz, A.E., 2015. Geothermal reservoir potential of volcaniclastic settings: The Valley of Mexico, Central Mexico. Renewable Energy. [in press] Muffler, P., Cataldi, R., 1978. Methods for regional assessment of geothermal resources. Geothermics, 7, 53-89.

Lighting and vegetation for energy-efficient and safe roadway travel.

DOT National Transportation Integrated Search

2009-04-01

The objective of the present study was to identify and evaluate promising approaches to incorporating : lighting and vegetation along roadways with the purpose of identifying the most promising application that : could be incorporated into a demonstr...

Spectrum Control through Discrete Frequency Diffraction in the Presence of Photonic Gauge Potentials

NASA Astrophysics Data System (ADS)

Qin, Chengzhi; Zhou, Feng; Peng, Yugui; Sounas, Dimitrios; Zhu, Xuefeng; Wang, Bing; Dong, Jianji; Zhang, Xinliang; Alù; , Andrea; Lu, Peixiang

2018-03-01

By using optical phase modulators in a fiber-optical circuit, we theoretically and experimentally demonstrate large control over the spectrum of an impinging signal, which may evolve analogously to discrete diffraction in spatial waveguide arrays. The modulation phase acts as a photonic gauge potential in the frequency dimension, realizing efficient control of the central frequency and bandwidth of frequency combs. We experimentally achieve a 50 GHz frequency shift and threefold bandwidth expansion of an impinging comb, as well as the frequency analogue of various refraction phenomena, including negative refraction and perfect focusing in the frequency domain, both for discrete and continuous incident spectra. Our study paves a promising way towards versatile frequency management for optical communications and signal processing using time modulation schemes.

Non-toxic fluorescent phosphonium probes to detect mitochondrial potential.

PubMed

Šarić, Ana; Crnolatac, Ivo; Bouillaud, Frédéric; Sobočanec, Sandra; Mikecin, Ana-Matea; Mačak Šafranko, Željka; Delgeorgiev, Todor; Piantanida, Ivo; Balog, Tihomir; Petit, Patrice X

2017-03-22

We evaluated our phosphonium-based fluorescent probes for selective staining of mitochondria. Currently used probes for monitoring mitochondrial membrane potential show varying degrees of interference with cell metabolism, photo-induced damage and probe binding. Here presented probes are characterised by highly efficient cellular uptake and specific accumulation in mitochondria. Fluorescent detection of the probes was accomplished using flow cytometry and confocal microscopy imaging of yeast and mammalian cells. Toxicity analysis (impedimetry-xCELLigence for the cellular proliferation and Seahorse technology for respiratory properties) confirms that these dyes exhibit no-toxicity on mitochondrial or cellular functioning even for long time incubation. The excellent chemical and photophysical stability of the dyes makes them promising leads toward improved fluorescent probes. Therefore, the probes described here offer to circumvent the problems associated with existing-probe's limitations.

Laser-driven beam lines for delivering intensity modulated radiation therapy with particle beams

PubMed Central

Hofmann, Kerstin M; Schell, Stefan; Wilkens, Jan J

2012-01-01

Abstract Laser-accelerated particles are a promising option for radiation therapy of cancer by potentially combining a compact, cost-efficient treatment unit with the physical advantages of charged particle beams. To design such a treatment unit we consider different dose delivery schemes and analyze the necessary devices in the required particle beam line for each case. Furthermore, we point out that laser-driven treatment units may be ideal tools for motion adaptation during radiotherapy. Reasons for this are the potential of a flexible gantry and the time structure of the beam with high particle numbers in ultrashort bunches. One challenge that needs to be addressed is the secondary radiation produced in several beam line elements. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) PMID:22930653

Novel Fabrication of Biodegradable Superabsorbent Microspheres with Diffusion Barrier through Thermo-Chemical Modification and Their Potential Agriculture Applications for Water Holding and Sustained Release of Fertilizer.

PubMed

Feng, Diejing; Bai, Bo; Wang, Honglun; Suo, Yourui

2017-07-26

Synergistic utilization of water and fertilizer has vital contribution to the modern production of agriculture. This work reports on a simple and facile strategy to prepare biodegradable yeast/sodium alginate/poly(vinyl alcohol) superabsorbent microspheres with a diffusion barrier merit by thermo-chemical modification route. The integrated performances, including water absorbency, water retention, water evaporation ratio, leaching loss control, sustained-release behaviors, and degradation in soil, were systematically investigated. The results revealed that the modified microspheres were a triumphant water and fertilizer manager to effectively hold water and control the unexpected leakage of fertilizer for sustained release. Therefore, this work provides a promising approach to ameliorate the utilization efficiency of water and fertilizer in potential agriculture applications.

Death receptor 3 signaling enhances proliferation of human regulatory T cells.

PubMed

Bittner, Sebastian; Knoll, Gertrud; Ehrenschwender, Martin

2017-04-01

Exploiting regulatory T cells (Tregs) to control aberrant immune reactions is a promising therapeutic approach, but is hampered by their relative paucity. In mice, activation of death receptor 3 (DR3), a member of the TNF-receptor superfamily (TNFRSF), increases Treg frequency and efficiently controls exuberant immune activation. For human Tregs, neither DR3 expression nor potential functions have been described. Here, we show that human Tregs express DR3 and demonstrate DR3-mediated activation of p38, ERK, and NFκB. DR3 stimulation enhances Treg expansion ex vivo while retaining their suppressive capacity. In summary, our results establish a functional role for DR3 signaling in human Tregs and could potentially help to tailor Treg-based therapies. © 2017 Federation of European Biochemical Societies.

Applying Behavioral Economics to Public Health Policy: Illustrative Examples and Promising Directions.

PubMed

Matjasko, Jennifer L; Cawley, John H; Baker-Goering, Madeleine M; Yokum, David V

2016-05-01

Behavioral economics provides an empirically informed perspective on how individuals make decisions, including the important realization that even subtle features of the environment can have meaningful impacts on behavior. This commentary provides examples from the literature and recent government initiatives that incorporate concepts from behavioral economics in order to improve health, decision making, and government efficiency. The examples highlight the potential for behavioral economics to improve the effectiveness of public health policy at low cost. Although incorporating insights from behavioral economics into public health policy has the potential to improve population health, its integration into government public health programs and policies requires careful design and continual evaluation of such interventions. Limitations and drawbacks of the approach are discussed. Copyright © 2016 American Journal of Preventive Medicine. All rights reserved.

Non-toxic fluorescent phosphonium probes to detect mitochondrial potential

NASA Astrophysics Data System (ADS)

Šarić, Ana; Crnolatac, Ivo; Bouillaud, Frédéric; Sobočanec, Sandra; Mikecin, Ana-Matea; Mačak Šafranko, Željka; Delgeorgiev, Todor; Piantanida, Ivo; Balog, Tihomir; Petit, Patrice X.

2017-03-01

We evaluated our phosphonium-based fluorescent probes for selective staining of mitochondria. Currently used probes for monitoring mitochondrial membrane potential show varying degrees of interference with cell metabolism, photo-induced damage and probe binding. Here presented probes are characterised by highly efficient cellular uptake and specific accumulation in mitochondria. Fluorescent detection of the probes was accomplished using flow cytometry and confocal microscopy imaging of yeast and mammalian cells. Toxicity analysis (impedimetry—xCELLigence for the cellular proliferation and Seahorse technology for respiratory properties) confirms that these dyes exhibit no-toxicity on mitochondrial or cellular functioning even for long time incubation. The excellent chemical and photophysical stability of the dyes makes them promising leads toward improved fluorescent probes. Therefore, the probes described here offer to circumvent the problems associated with existing-probe’s limitations.

Direct cytosolic delivery of cargoes in vivo by a chimera consisting of D- and L-arginine residues.

PubMed

Ma, Yan; Gong, Cheng; Ma, Yilong; Fan, Fengkai; Luo, Meijie; Yang, Fei; Zhang, Yu-Hui

2012-09-10

The ability of cell-penetrating peptides (CPPs) to deliver a range of membrane-impermeable molecules into living cells makes them attractive potential vehicles for therapeutics. However, in vivo, the efficiency of CPP delivery to the cytosol remains unsatisfactory owing to endosomal entrapment and/or systemic toxicity, which severely restrict their bioavailability and efficacy in in vivo applications. In this study, we developed a series of novel chimeras consisting of various numbers of d- and l-arginine residues and investigated their cellular uptake behaviors and systemic toxicities. We demonstrated that the intracellular distribution, uptake efficiency, and systemic toxicity of these oligoarginines were all significantly affected by the number of d-arginine residues in the peptide sequence. We also found that a hybrid peptide, (rR)(3)R(2), possessed low systemic toxicity, high uptake efficiency, and, remarkably, achieved efficient cytosolic delivery not only in cultured cells but also in living tissue cells in mice after intravenous injection, implying that this heterogeneous motif might have promising applications in the delivery of cargoes of small sizes directed to cytosolic targets in vivo. Our studies into the uptake mechanism of (rR)(3)R(2) indicate that its cellular uptake was not affected by pharmacological or physical inhibitors of endocytosis but by the elimination of the membrane potential, suggesting that (rR)(3)R(2) does not enter the cells via endocytosis but rather through direct membrane translocation driven by the membrane potential. The results here might provide useful guidelines for the design and application of CPPs in drug delivery. Copyright © 2012 Elsevier B.V. All rights reserved.

Cell and tissue engineering and clinical applications: an overview.

PubMed

Stoltz, J F; Bensoussan, D; Decot, V; Ciree, A; Netter, P; Gillet, P

2006-01-01

Most human tissues do not regenerate spontaneously; this is why cell therapies and tissue engineering are promising alternatives. The principle is simple: cells are collected in a patient and introduced in the damaged tissue or in a tridimentional porous support and harvested in a bioreactor in which the physico-chemical and mechanical parameters are controlled. Once the tissues (or the cells) are mature they may be implanted. In parallel, the development of biotherapies with stem cells is a field of research in turmoil given the hopes for clinical applications that it brings up. Embryonic stem cells are potentially more interesting since they are totipotent, but they can only be obtained at the very early stages of the embryo. The potential of adult stem cells is limited but isolating them induces no ethical problem and it has been known for more than 40 years that bone marrow does possess the regenerating functions of blood cells. Finally, the properties of foetal stem cells (blood cells from the umbilical cord) are forerunners of the haematopoietic system but the ability of these cells to participate to the formation of other tissues is more problematic. Another field for therapeutic research is that of dendritic cells, antigen presenting cells. Their efficiency in cell therapy relies on the initiation of specific immune responses. They represent a promising tool in the development of a protective immune response against antigens which the host is usually unable to generate an efficient response (melanomas, breast against cancer, prostate cancer, ..). Finally, gene therapy, has been nourishing high hopes but few clinical applications can be envisaged in the short term, although potential applications are multiple (haemophilia, myopathies, ..). A large number of clinical areas stand as candidates for clinical applications: leukaemia and cancers, cardiac insufficiency and vascular diseases, cartilage and bone repair, ligaments and tendons, liver diseases, ophthalmology, diabetes, neurological diseases (Parkinson, Huntington disease, ..), .. Various aspects of this new regenerative therapeutic medicine are developed in this work.

GaN transistors on Si for switching and high-frequency applications

NASA Astrophysics Data System (ADS)

Ueda, Tetsuzo; Ishida, Masahiro; Tanaka, Tsuyoshi; Ueda, Daisuke

2014-10-01

In this paper, recent advances of GaN transistors on Si for switching and high-frequency applications are reviewed. Novel epitaxial structures including superlattice interlayers grown by metal organic chemical vapor deposition (MOCVD) relieve the strain and eliminate the cracks in the GaN over large-diameter Si substrates up to 8 in. As a new device structure for high-power switching application, Gate Injection Transistors (GITs) with a p-AlGaN gate over an AlGaN/GaN heterostructure successfully achieve normally-off operations maintaining high drain currents and low on-state resistances. Note that the GITs on Si are free from current collapse up to 600 V, by which the drain current would be markedly reduced after the application of high drain voltages. Highly efficient operations of an inverter and DC-DC converters are presented as promising applications of GITs for power switching. The high efficiencies in an inverter, a resonant LLC converter, and a point-of-load (POL) converter demonstrate the superior potential of the GaN transistors on Si. As for high-frequency transistors, AlGaN/GaN heterojuction field-effect transistors (HFETs) on Si designed specifically for microwave and millimeter-wave frequencies demonstrate a sufficiently high output power at these frequencies. Output powers of 203 W at 2.5 GHz and 10.7 W at 26.5 GHz are achieved by the fabricated GaN transistors. These devices for switching and high-frequency applications are very promising as future energy-efficient electronics because of their inherent low fabrication cost and superior device performance.

Histological assessment of follicular delivery of flutamide by solid lipid nanoparticles: potential tool for the treatment of androgenic alopecia.

PubMed

Hamishehkar, Hamed; Ghanbarzadeh, Saeed; Sepehran, Sasan; Javadzadeh, Yousef; Adib, Zahra Mardhiah; Kouhsoltani, Maryam

2016-01-01

Flutamide is a potent anti-androgen with the several unwanted side effects in systemic administration, therefore, it has attracted special interest in the development of topically applied formulations for the treatment of androgenic alopecia. The purpose of this study was to prepare and characterize the solid lipid nanoparticles (SLNs) of Flutamide for follicular targeting in the treatment of the androgenic alopecia. Flutamide-loaded SLNs, promising drug carriers for topical application were prepared by hot melt homogenization method. Drug permeation and accumulation in the exercised rat skin and histological study on the male hamsters were performed to assess drug delivery efficiency in vitro and in vivo, respectively. The optimized Flutamide-loaded SLNs (size 198 nm, encapsulation efficiency percentage 65% and loading efficiency percentage 3.27%) exhibited a good stability during the period of at least 2 months. The results of X-ray diffraction showed Flutamide amorphous state confirming uniform drug dispersion in the SLNs structure. Higher skin drug deposition (1.75 times) of SLN formulation compared to Flutamide hydroalcoholic solution represented better localization of the drug in the skin. The in vivo studies showed more new hair follicle growth by utilizing Flutamide-loaded SLNs than Flutamide hydroalcoholic solution which could be due to the higher accumulation of SLNs in the hair follicles as well as slowly and continues release of the Flutamide through the SLNs maximizing hair follicle exposure by antiandrogenic drug. It was concluded Flutamide-loaded SLN formulation can be used as a promising colloidal drug carriers for topical administration of Flutamide in the treatment of androgenic alopecia.

Design Studies of a CZT-based Detector Combined with a Pixel-Geometry-Matching Collimator for SPECT Imaging.

PubMed

Weng, Fenghua; Bagchi, Srijeeta; Huang, Qiu; Seo, Youngho

2013-10-01

Single Photon Emission Computed Tomography (SPECT) suffers limited efficiency due to the need for collimators. Collimator properties largely decide the data statistics and image quality. Various materials and configurations of collimators have been investigated in many years. The main thrust of our study is to evaluate the design of pixel-geometry-matching collimators to investigate their potential performances using Geant4 Monte Carlo simulations. Here, a pixel-geometry-matching collimator is defined as a collimator which is divided into the same number of pixels as the detector's and the center of each pixel in the collimator is a one-to-one correspondence to that in the detector. The detector is made of Cadmium Zinc Telluride (CZT), which is one of the most promising materials for applications to detect hard X-rays and γ -rays due to its ability to obtain good energy resolution and high light output at room temperature. For our current project, we have designed a large-area, CZT-based gamma camera (20.192 cm×20.192 cm) with a small pixel pitch (1.60 mm). The detector is pixelated and hence the intrinsic resolution can be as small as the size of the pixel. Materials of collimator, collimator hole geometry, detection efficiency, and spatial resolution of the CZT detector combined with the pixel-matching collimator were calculated and analyzed under different conditions. From the simulation studies, we found that such a camera using rectangular holes has promising imaging characteristics in terms of spatial resolution, detection efficiency, and energy resolution.

Redox-sensitive micelles composed of disulfide-linked Pluronic-linoleic acid for enhanced anticancer efficiency of brusatol

PubMed Central

Chan, Hon Fai; Lin, Zhixiu; Wang, Yitao

2018-01-01

Brusatol (Bru) exhibits promising anticancer effects, with both proliferation inhibition and chemoresistance amelioration activity. However, the poor solubility and insufficient intracellular delivery of Bru greatly restrict its application. Herein, to simultaneously utilize the advantages of Pluronics as drug carriers and tumor microenvironment-responsive drug release profiles, a flexible amphiphilic copolymer with a polymer skeleton, that is, Pluronic® F68 grafting with linoleic acid moieties by redox-reducible disulfide bonds (F68-SS-LA), was synthesized. After characterization by 1H-nuclear magnetic resonance and Fourier transform infrared spectroscopy, the redox-sensitive F68-SS-LA micelles were self-assembled in a much lower critical micelle concentration than that of the unmodified F68 copolymer. Bru was loaded in micelles (Bru/SS-M) with high loading efficiency, narrow size distribution, and excellent storage stability. The redox-sensitive Bru/SS-M exhibited rapid particle dissociation and drug release in response to a redox environment. Based on the enhanced cellular internalization, Bru/SS-M achieved higher cytotoxicity in both Bel-7402 and MCF-7 cells compared with free Bru and nonreducible micelles. The improved anticancer effect was attributed to the remarkably decreased mitochondrial membrane potential and increased reactive oxygen species level as well as apoptotic rate. These results demonstrated that F68-SS-LA micelles possess great potential as an efficient delivery vehicle for Bru to promote its anticancer efficiency via an oxidation pathway. PMID:29491708

Identifying/Quantifying Environmental Trade-offs Inherent in GHG Reduction Strategies for Coal-Fired Power.

PubMed

Schivley, Greg; Ingwersen, Wesley W; Marriott, Joe; Hawkins, Troy R; Skone, Timothy J

2015-07-07

Improvements to coal power plant technology and the cofired combustion of biomass promise direct greenhouse gas (GHG) reductions for existing coal-fired power plants. Questions remain as to what the reduction potentials are from a life cycle perspective and if it will result in unintended increases in impacts to air and water quality and human health. This study provides a unique analysis of the potential environmental impact reductions from upgrading existing subcritical pulverized coal power plants to increase their efficiency, improving environmental controls, cofiring biomass, and exporting steam for industrial use. The climate impacts are examined in both a traditional-100 year GWP-method and a time series analysis that accounts for emission and uptake timing over the life of the power plant. Compared to fleet average pulverized bed boilers (33% efficiency), we find that circulating fluidized bed boilers (39% efficiency) may provide GHG reductions of about 13% when using 100% coal and reductions of about 20-37% when cofiring with 30% biomass. Additional greenhouse gas reductions from combined heat and power are minimal if the steam coproduct displaces steam from an efficient natural gas boiler. These upgrades and cofiring biomass can also reduce other life cycle impacts, although there may be increased impacts to water quality (eutrophication) when using biomass from an intensely cultivated source. Climate change impacts are sensitive to the timing of emissions and carbon sequestration as well as the time horizon over which impacts are considered, particularly for long growth woody biomass.

LOW-ENGINE-FRICTION TECHNOLOGY FOR ADVANCED NATURAL-GAS RECIPROCATING ENGINES

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

Victor Wong; Tian Tian; Luke Moughon

This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston and piston ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and wear. An iterative process of simulation, experimentation and analysis is being followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. To date, a detailed set of piston and piston-ring dynamic and friction models have been developed and applied that illustrate the fundamental relationships among mechanical, surface/material and lubricant design parameters and friction losses. Demonstration of low-friction ring-pack designs in the Waukesha VGFmore » 18GL engine confirmed total engine FEMP (friction mean effective pressure) reduction of 7-10% from the baseline configuration without significantly increasing oil consumption or blow-by flow. This represents a substantial (30-40%) reduction of the ringpack friction alone. The measured FMEP reductions were in good agreement with the model predictions. Further improvements via piston, lubricant, and surface designs offer additional opportunities. Tests of low-friction lubricants are in progress and preliminary results are very promising. The combined analysis of lubricant and surface design indicates that low-viscosity lubricants can be very effective in reducing friction, subject to component wear for extremely thin oils, which can be mitigated with further lubricant formulation and/or engineered surfaces. Hence a combined approach of lubricant design and appropriate wear reduction offers improved potential for minimum engine friction loss. Piston friction studies indicate that a flatter piston with a more flexible skirt, together with optimizing the waviness and film thickness on the piston skirt offer significant friction reduction. Combined with low-friction ring-pack, material and lubricant parameters, a total power cylinder friction reduction of 30-50% is expected, translating to an engine efficiency increase of two percentage points from its current baseline towards the goal of 50% ARES engine efficiency. The design strategies developed in this study have promising potential for application in all modern reciprocating engines as they represent simple, low-cost methods to extract significant fuel savings. The current program has possible spinoffs and applications in other industries as well, including transportation, CHP, and diesel power generation. The progress made in this program has wide engine efficiency implications, and potential deployment of low-friction engine components or lubricants in the near term is possible as current investigations continue.« less

Directed transport by surface chemical potential gradients for enhancing analyte collection in nanoscale sensors.

PubMed

Sitt, Amit; Hess, Henry

2015-05-13

Nanoscale detectors hold great promise for single molecule detection and the analysis of small volumes of dilute samples. However, the probability of an analyte reaching the nanosensor in a dilute solution is extremely low due to the sensor's small size. Here, we examine the use of a chemical potential gradient along a surface to accelerate analyte capture by nanoscale sensors. Utilizing a simple model for transport induced by surface binding energy gradients, we study the effect of the gradient on the efficiency of collecting nanoparticles and single and double stranded DNA. The results indicate that chemical potential gradients along a surface can lead to an acceleration of analyte capture by several orders of magnitude compared to direct collection from the solution. The improvement in collection is limited to a relatively narrow window of gradient slopes, and its extent strongly depends on the size of the gradient patch. Our model allows the optimization of gradient layouts and sheds light on the fundamental characteristics of chemical potential gradient induced transport.

Improved blackwater disinfection using potentiodynamic methods with oxidized boron-doped diamond electrodes.

PubMed

Thostenson, J O; Mourouvin, R; Hawkins, B T; Ngaboyamahina, E; Sellgren, K L; Parker, C B; Deshusses, M A; Stoner, B R; Glass, J T

2018-09-01

Electrochemical disinfection (ECD) has become an important blackwater disinfection technology. ECD is a promising solution for the 2 billion people without access to conventional sanitation practices and in areas deficient in basic utilities (e.g., sewers, electricity, waste treatment). Here, we report on the disinfection of blackwater using potential cycling compared to potentiostatic treatment methods in chloride-containing and chloride-free solutions of blackwater (i.e., untreated wastewater containing feces, urine, and flushwater from a toilet). Potentiodynamic treatment is demonstrated to improve disinfection energy efficiency of blackwater by 24% and 124% compared to static oxidation and reduction methods, respectively. The result is shown to be caused by electrochemical advanced oxidation processes (EAOP) and regeneration of sp 2 -surface-bonded carbon functional groups that serve the dual purpose of catalysts and adsorption sites of oxidant intermediates. Following 24 h electrolysis in blackwater, electrode fouling is shown to be minimized by the potential cycling method when compared to equivalent potentiostatic methods. The potential cycling current density is 40% higher than both the static oxidative and reductive methods. This work enhances the understanding of oxygen reduction catalysts using functionalized carbon materials and electrochemical disinfection anodes, both of which have the potential to bring a cost-effective, energy efficient, and practical solution to the problem of disinfecting blackwater. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

77 FR 56194 - Promising and Practical Strategies to Increase Postsecondary Success; Request for Information

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-12

.../Remedial Education Digital Materials Disability Services Dual Degrees Earn and Learn Efficiency Employer... Accelerated Learning Accessible Materials Achievement Gap Closure Adult Education Affordability Assessment... DEPARTMENT OF EDUCATION Promising and Practical Strategies to Increase Postsecondary Success...

Screening Nylon-3 Polymers, a New Class of Cationic Amphiphiles, for siRNA Delivery

PubMed Central

2015-01-01

Amphiphilic nucleic acid carriers have attracted strong interest. Three groups of nylon-3 copolymers (poly-β-peptides) possessing different cationic/hydrophobic content were evaluated as siRNA delivery agents in this study. Their ability to condense siRNA was determined in SYBR Gold assays. Their cytotoxicity was tested by MTT assays, their efficiency of delivering Alexa Fluor-488-labeled siRNA intracellularly in the presence and absence of uptake inhibitors was assessed by flow cytometry, and their transfection efficacies were studied by luciferase knockdown in a cell line stably expressing luciferase (H1299/Luc). Endosomal release was determined by confocal laser scanning microscopy and colocalization with lysotracker. All polymers efficiently condensed siRNA at nitrogen-to-phosphate (N/P) ratios of 5 or lower, as reflected in hydrodynamic diameters smaller than that at N/P 1. Although several formulations had negative zeta potentials at N/P 1, G2C and G2D polyplexes yielded >80% uptake in H1299/Luc cells, as determined by flow cytometry. Luciferase knockdown (20–65%) was observed after transfection with polyplexes made of the high molecular weight polymers that were the most hydrophobic. The ability of nylon-3 polymers to deliver siRNA intracellularly even at negative zeta potential implies that they mediate transport across cell membranes based on their amphiphilicity. The cellular uptake route was determined to strongly depend on the presence of cholesterol in the cell membrane. These polymers are, therefore, very promising for siRNA delivery at reduced surface charge and toxicity. Our study identified nylon-3 formulations at low N/P ratios for effective gene knockdown, indicating that nylon-3 polymers are a new, promising type of gene delivery agent. PMID:25437915

The role of surfactants in the formulation of elastic liposomal gels containing a synthetic opioid analgesic.

PubMed

Singh, Sima; Vardhan, Harsh; Kotla, Niranjan G; Maddiboyina, Balaji; Sharma, Dinesh; Webster, Thomas J

2016-01-01

Transdermal drug delivery systems have made significant contributions to the medical community, but have yet to completely substitute oral or parenteral delivery. Recently, various strategies have been used to augment the transdermal delivery of therapeutics. Primarily, they include iontophoresis, electrophoresis, sonophoresis, chemical permeation enhancers, microneedles, and vesicular systems. Among these strategies, elastic liposomes appear promising. Elastic vesicle scaffolds have been developed and evaluated as novel topical and transdermal delivery systems, with an infrastructure consisting of hydrophobic and hydrophilic moieties together, and as a result, such scaffolds can accommodate drug molecules with a wide range of solubility. High deformability of these vesicles provides for better penetration of intact vesicles. This system is much more efficient at delivering low- and high-molecular-weight drugs to the skin in terms of quantity and depth. In this work, elastic liposomes of Tramadol HCl were prepared using a solvent evaporation method with different surfactants and were characterized using microscopy, and particle size, shape, drug content, ex vivo release, and zeta potential were also calculated. The prepared elastic liposomes were found to be in the range of 152.4 nm with a zeta potential of -22.4 mV; the entrapment efficiencies of the selected formulation was found to be 79.71%±0.27%. All formulations in the form of a gel were evaluated for physicochemical properties and were found to be homogeneous with no grittiness, and the pH of all formulations was found to be neutral. The optimized selected elastic liposomal formulation followed the Higuchi equation and Fickian diffusion and released the drug for a period of 24 hours. The overall results provide much promise for the continued investigation of deformable vesicles as transdermal drug carriers.

Screening nylon-3 polymers, a new class of cationic amphiphiles, for siRNA delivery.

PubMed

Nadithe, Venkatareddy; Liu, Runhui; Killinger, Bryan A; Movassaghian, Sara; Kim, Na Hyung; Moszczynska, Anna B; Masters, Kristyn S; Gellman, Samuel H; Merkel, Olivia M

2015-02-02

Amphiphilic nucleic acid carriers have attracted strong interest. Three groups of nylon-3 copolymers (poly-β-peptides) possessing different cationic/hydrophobic content were evaluated as siRNA delivery agents in this study. Their ability to condense siRNA was determined in SYBR Gold assays. Their cytotoxicity was tested by MTT assays, their efficiency of delivering Alexa Fluor-488-labeled siRNA intracellularly in the presence and absence of uptake inhibitors was assessed by flow cytometry, and their transfection efficacies were studied by luciferase knockdown in a cell line stably expressing luciferase (H1299/Luc). Endosomal release was determined by confocal laser scanning microscopy and colocalization with lysotracker. All polymers efficiently condensed siRNA at nitrogen-to-phosphate (N/P) ratios of 5 or lower, as reflected in hydrodynamic diameters smaller than that at N/P 1. Although several formulations had negative zeta potentials at N/P 1, G2C and G2D polyplexes yielded >80% uptake in H1299/Luc cells, as determined by flow cytometry. Luciferase knockdown (20-65%) was observed after transfection with polyplexes made of the high molecular weight polymers that were the most hydrophobic. The ability of nylon-3 polymers to deliver siRNA intracellularly even at negative zeta potential implies that they mediate transport across cell membranes based on their amphiphilicity. The cellular uptake route was determined to strongly depend on the presence of cholesterol in the cell membrane. These polymers are, therefore, very promising for siRNA delivery at reduced surface charge and toxicity. Our study identified nylon-3 formulations at low N/P ratios for effective gene knockdown, indicating that nylon-3 polymers are a new, promising type of gene delivery agent.

Characterization of polyethylene glycol-grafted polyethylenimine and superparamagnetic iron oxide nanoparticles (PEG-g-PEI-SPION) as an MRI-visible vector for siRNA delivery in gastric cancer in vitro and in vivo.

PubMed

Chen, Yinting; Lian, Guoda; Liao, Chengde; Wang, Weiwei; Zeng, Linjuan; Qian, Chenchen; Huang, Kaihong; Shuai, Xintao

2013-07-01

Gene therapy is a promising therapeutic method but is severely hampered due to its lack of an ideal delivery system. Therefore, in this study, a nonviral and magnetic resonance imaging (MRI) visible vector, polyethylene glycol-grafted polyethylenimine and superparamagnetic iron oxide nanoparticles (PEG-g-PEI-SPION) was used as a nanocarrier for small interfering RNA (siRNA) delivery in gastric cancer. Biophysical characterization of PEG-g-PEI-SPION was systematically analyzed, including size, zeta potential, siRNA condensation capacity, cell viability, transfection efficiency, cellular uptake, and MRI-visible function in vivo. Besides, CD44 variant isoform 6 (CD44v6), a protein marker for metastatic behavior in gastric cancer, and was chose as the target gene to further analyze the siRNA delivery function of PEG-g-PEI-SPION. Under comprehensive analysis, the appropriate N/P ratio of PEG-g-PEI-SPION/siRNA was 10, and siRNA targeting at human CD44v6 (siCD44v6) transferred by PEG-g-PEI-SPION was effective at downregulating the CD44v6 expression of gastric carcinoma cell line SGC-7901 in vitro. Moreover, knockdown of CD44v6 impaired migrating and invasive abilities of SGC-7901 cells. Furthermore, PEG-g-PEI-SPION was a highly efficient contrast agent for MRI scan in vivo. PEG-g-PEI-SPION was a promising nonviral vector with molecular image tracing capacity for cancer gene therapy. And CD44v6 was a potential target gene for the prevention and detection of metastatic behavior in gastric cancer.

Trial Promoter: A Web-Based Tool for Boosting the Promotion of Clinical Research Through Social Media.

PubMed

Reuter, Katja; Ukpolo, Francis; Ward, Edward; Wilson, Melissa L; Angyan, Praveen

2016-06-29

Scarce information about clinical research, in particular clinical trials, is among the top reasons why potential participants do not take part in clinical studies. Without volunteers, on the other hand, clinical research and the development of novel approaches to preventing, diagnosing, and treating disease are impossible. Promising digital options such as social media have the potential to work alongside traditional methods to boost the promotion of clinical research. However, investigators and research institutions are challenged to leverage these innovations while saving time and resources. To develop and test the efficiency of a Web-based tool that automates the generation and distribution of user-friendly social media messages about clinical trials. Trial Promoter is developed in Ruby on Rails, HTML, cascading style sheet (CSS), and JavaScript. In order to test the tool and the correctness of the generated messages, clinical trials (n=46) were randomized into social media messages and distributed via the microblogging social media platform Twitter and the social network Facebook. The percent correct was calculated to determine the probability with which Trial Promoter generates accurate messages. During a 10-week testing phase, Trial Promoter automatically generated and published 525 user-friendly social media messages on Twitter and Facebook. On average, Trial Promoter correctly used the message templates and substituted the message parameters (text, URLs, and disease hashtags) 97.7% of the time (1563/1600). Trial Promoter may serve as a promising tool to render clinical trial promotion more efficient while requiring limited resources. It supports the distribution of any research or other types of content. The Trial Promoter code and installation instructions are freely available online.

Trial Promoter: A Web-Based Tool for Boosting the Promotion of Clinical Research Through Social Media

PubMed Central

Ukpolo, Francis; Ward, Edward; Wilson, Melissa L

2016-01-01

Background Scarce information about clinical research, in particular clinical trials, is among the top reasons why potential participants do not take part in clinical studies. Without volunteers, on the other hand, clinical research and the development of novel approaches to preventing, diagnosing, and treating disease are impossible. Promising digital options such as social media have the potential to work alongside traditional methods to boost the promotion of clinical research. However, investigators and research institutions are challenged to leverage these innovations while saving time and resources. Objective To develop and test the efficiency of a Web-based tool that automates the generation and distribution of user-friendly social media messages about clinical trials. Methods Trial Promoter is developed in Ruby on Rails, HTML, cascading style sheet (CSS), and JavaScript. In order to test the tool and the correctness of the generated messages, clinical trials (n=46) were randomized into social media messages and distributed via the microblogging social media platform Twitter and the social network Facebook. The percent correct was calculated to determine the probability with which Trial Promoter generates accurate messages. Results During a 10-week testing phase, Trial Promoter automatically generated and published 525 user-friendly social media messages on Twitter and Facebook. On average, Trial Promoter correctly used the message templates and substituted the message parameters (text, URLs, and disease hashtags) 97.7% of the time (1563/1600). Conclusions Trial Promoter may serve as a promising tool to render clinical trial promotion more efficient while requiring limited resources. It supports the distribution of any research or other types of content. The Trial Promoter code and installation instructions are freely available online. PMID:27357424

The role of surfactants in the formulation of elastic liposomal gels containing a synthetic opioid analgesic

PubMed Central

Singh, Sima; Vardhan, Harsh; Kotla, Niranjan G; Maddiboyina, Balaji; Sharma, Dinesh; Webster, Thomas J

2016-01-01

Transdermal drug delivery systems have made significant contributions to the medical community, but have yet to completely substitute oral or parenteral delivery. Recently, various strategies have been used to augment the transdermal delivery of therapeutics. Primarily, they include iontophoresis, electrophoresis, sonophoresis, chemical permeation enhancers, microneedles, and vesicular systems. Among these strategies, elastic liposomes appear promising. Elastic vesicle scaffolds have been developed and evaluated as novel topical and transdermal delivery systems, with an infrastructure consisting of hydrophobic and hydrophilic moieties together, and as a result, such scaffolds can accommodate drug molecules with a wide range of solubility. High deformability of these vesicles provides for better penetration of intact vesicles. This system is much more efficient at delivering low- and high-molecular-weight drugs to the skin in terms of quantity and depth. In this work, elastic liposomes of Tramadol HCl were prepared using a solvent evaporation method with different surfactants and were characterized using microscopy, and particle size, shape, drug content, ex vivo release, and zeta potential were also calculated. The prepared elastic liposomes were found to be in the range of 152.4 nm with a zeta potential of −22.4 mV; the entrapment efficiencies of the selected formulation was found to be 79.71%±0.27%. All formulations in the form of a gel were evaluated for physicochemical properties and were found to be homogeneous with no grittiness, and the pH of all formulations was found to be neutral. The optimized selected elastic liposomal formulation followed the Higuchi equation and Fickian diffusion and released the drug for a period of 24 hours. The overall results provide much promise for the continued investigation of deformable vesicles as transdermal drug carriers. PMID:27114707

Development of Modeling Approaches for Nuclear Thermal Propulsion Test Facilities

NASA Technical Reports Server (NTRS)

Jones, Daniel R.; Allgood, Daniel C.; Nguyen, Ke

2014-01-01

High efficiency of rocket propul-sion systems is essential for humanity to venture be-yond the moon. Nuclear Thermal Propulsion (NTP) is a promising alternative to conventional chemical rock-ets with relatively high thrust and twice the efficiency of the Space Shuttle Main Engine. NASA is in the pro-cess of developing a new NTP engine, and is evaluat-ing ground test facility concepts that allow for the thor-ough testing of NTP devices. NTP engine exhaust, hot gaseous hydrogen, is nominally expected to be free of radioactive byproducts from the nuclear reactor; how-ever, it has the potential to be contaminated due to off-nominal engine reactor performance. Several options are being investigated to mitigate this hazard potential with one option in particular that completely contains the engine exhaust during engine test operations. The exhaust products are subsequently disposed of between engine tests. For this concept (see Figure 1), oxygen is injected into the high-temperature hydrogen exhaust that reacts to produce steam, excess oxygen and any trace amounts of radioactive noble gases released by off-nominal NTP engine reactor performance. Water is injected to condense the potentially contaminated steam into water. This water and the gaseous oxygen (GO2) are subsequently passed to a containment area where the water and GO2 are separated into separate containment tanks.

Towards rewritable multilevel optical data storage in single nanocrystals.

PubMed

Riesen, Nicolas; Pan, Xuanzhao; Badek, Kate; Ruan, Yinlan; Monro, Tanya M; Zhao, Jiangbo; Ebendorff-Heidepriem, Heike; Riesen, Hans

2018-04-30

Novel approaches for digital data storage are imperative, as storage capacities are drastically being outpaced by the exponential growth in data generation. Optical data storage represents the most promising alternative to traditional magnetic and solid-state data storage. In this paper, a novel and energy efficient approach to optical data storage using rare-earth ion doped inorganic insulators is demonstrated. In particular, the nanocrystalline alkaline earth halide BaFCl:Sm is shown to provide great potential for multilevel optical data storage. Proof-of-concept demonstrations reveal for the first time that these phosphors could be used for rewritable, multilevel optical data storage on the physical dimensions of a single nanocrystal. Multilevel information storage is based on the very efficient and reversible conversion of Sm 3+ to Sm 2+ ions upon exposure to UV-C light. The stored information is then read-out using confocal optics by employing the photoluminescence of the Sm 2+ ions in the nanocrystals, with the signal strength depending on the UV-C fluence used during the write step. The latter serves as the mechanism for multilevel data storage in the individual nanocrystals, as demonstrated in this paper. This data storage platform has the potential to be extended to 2D and 3D memory for storage densities that could potentially approach petabyte/cm 3 levels.

The quadrupole model for rigid-body gravity simulations

NASA Astrophysics Data System (ADS)

Dobrovolskis, Anthony R.; Korycansky, D. G.

2013-07-01

We introduce two new models for gravitational simulations of systems of non-spherical bodies, such as comets and asteroids. In both models, one body (the "primary") may be represented by any convenient means, to arbitrary accuracy. In our first model, all of the other bodies are represented by small gravitational "molecules" consisting of a few point masses, rigidly linked together. In our second model, all of the other bodies are treated as point quadrupoles, with gravitational potentials including spherical harmonic terms up to the third degree (rather than only the first degree, as for ideal spheres or point masses). This quadrupole formulation may be regarded as a generalization of MacCullagh's approximation. Both models permit the efficient calculation of the interaction energy, the force, and the torque acting on a small body in an arbitrary external gravitational potential. We test both models for the cases of a triaxial ellipsoid, a rectangular parallelepiped, and "duplex" combinations of two spheres, all in a point-mass potential. These examples were chosen in order to compare the accuracy of our technique with known analytical results, but the ellipsoid and duplex are also useful models for comets and asteroids. We find that both approaches show significant promise for more efficient gravitational simulations of binary asteroids, for example. An appendix also describes the duplex model in detail.

Curcumin Conjugated with PLGA Potentiates Sustainability, Anti-Proliferative Activity and Apoptosis in Human Colon Carcinoma Cells

PubMed Central

Waghela, Bhargav N.; Sharma, Anupama; Dhumale, Suhashini; Pandey, Shashibahl M.; Pathak, Chandramani

2015-01-01

Curcumin, an ingredient of turmeric, exhibits a variety of biological activities such as anti-inflammatory, anti-atherosclerotic, anti-proliferative, anti-oxidant, anti-cancer and anti-metastatic. It is a highly pleiotropic molecule that inhibits cell proliferation and induces apoptosis in cancer cells. Despite its imperative biological activities, chemical instability, photo-instability and poor bioavailability limits its utilization as an effective therapeutic agent. Therefore, enhancing the bioavailability of curcumin may improve its therapeutic index for clinical setting. In the present study, we have conjugated curcumin with a biodegradable polymer Poly (D, L-lactic-co-glycolic acid) and evaluated its apoptotic potential in human colon carcinoma cells (HCT 116). The results show that curcumin-PLGA conjugate efficiently inhibits cell proliferation and cell survival in human colon carcinoma cells as compared to native curcumin. Additionally, curcumin conjugated with PLGA shows improved cellular uptake and exhibits controlled release at physiological pH as compared to native curcumin. The curcumin-PLGA conjugate efficiently activates the cascade of caspases and promotes intrinsic apoptotic signaling. Thus, the results suggest that conjugation potentiates the sustainability, anti-proliferative and apoptotic activity of curcumin. This approach could be a promising strategy to improve the therapeutic index of cancer therapy. PMID:25692854

Evaluation of counting methods for oceanic radium-228

NASA Astrophysics Data System (ADS)

Orr, James C.

1988-07-01

Measurement of open ocean 228Ra is difficult, typically requiring at least 200 L of seawater. The burden of collecting and processing these large-volume samples severely limits the widespread use of this promising tracer. To use smaller-volume samples, a more sensitive means of analysis is required. To seek out new and improved counting method(s), conventional 228Ra counting methods have been compared with some promising techniques which are currently used for other radionuclides. Of the conventional methods, α spectrometry possesses the highest efficiency (3-9%) and lowest background (0.0015 cpm), but it suffers from the need for complex chemical processing after sampling and the need to allow about 1 year for adequate ingrowth of 228Th granddaughter. The other two conventional counting methods measure the short-lived 228Ac daughter while it remains supported by 228Ra, thereby avoiding the complex sample processing and the long delay before counting. The first of these, high-resolution γ spectrometry, offers the simplest processing and an efficiency (4.8%) comparable to α spectrometry; yet its high background (0.16 cpm) and substantial equipment cost (˜30,000) limit its widespread use. The second no-wait method, β-γ coincidence spectrometry, also offers comparable efficiency (5.3%), but it possesses both lower background (0.0054 cpm) and lower initial cost (˜12,000). Three new (i.e., untried for 228Ra) techniques all seem to promise about a fivefold increase in efficiency over conventional methods. By employing liquid scintillation methods, both α spectrometry and β-γ coincidence spectrometry can improve their counter efficiency while retaining low background. The third new 228Ra counting method could be adapted from a technique which measures 224Ra by 220Rn emanation. After allowing for ingrowth and then counting for the 224Ra great-granddaughter, 228Ra could be back calculated, thereby yielding a method with high efficiency, where no sample processing is required. The efficiency and background of each of the three new methods have been estimated and are compared with those of the three methods currently employed to measure oceanic 228Ra. From efficiency and background, the relative figure of merit and the detection limit have been determined for each of the six counters. These data suggest that the new counting methods have the potential to measure most 228Ra samples with just 30 L of seawater, to better than 5% precision. Not only would this reduce the time, effort, and expense involved in sample collection, but 228Ra could then be measured on many small-volume samples (20-30 L) previously collected with only 226Ra in mind. By measuring 228Ra quantitatively on such small-volume samples, three analyses (large-volume 228Ra, large-volume 226Ra, and small-volume 226Ra) could be reduced to one, thereby dramatically improving analytical precision.

Fundamental rate-loss trade-off for the quantum internet

NASA Astrophysics Data System (ADS)

Azuma, Koji; Mizutani, Akihiro; Lo, Hoi-Kwong

2016-11-01

The quantum internet holds promise for achieving quantum communication--such as quantum teleportation and quantum key distribution (QKD)--freely between any clients all over the globe, as well as for the simulation of the evolution of quantum many-body systems. The most primitive function of the quantum internet is to provide quantum entanglement or a secret key to two points efficiently, by using intermediate nodes connected by optical channels with each other. Here we derive a fundamental rate-loss trade-off for a quantum internet protocol, by generalizing the Takeoka-Guha-Wilde bound to be applicable to any network topology. This trade-off has essentially no scaling gap with the quantum communication efficiencies of protocols known to be indispensable to long-distance quantum communication, such as intercity QKD and quantum repeaters. Our result--putting a practical but general limitation on the quantum internet--enables us to grasp the potential of the future quantum internet.

Electrochemical surface modification of carbon mesh anode to improve the performance of air-cathode microbial fuel cells.

PubMed

Luo, Jianmei; Chi, Meiling; Wang, Hongyu; He, Huanhuan; Zhou, Minghua

2013-12-01

A convenient and promising alternative to surface modification of carbon mesh anode was fulfilled by electrochemical oxidation in the electrolyte of nitric acid or ammonium nitrate at ambient temperature. It was confirmed that such an anode modification method was low cost and effective not only in improving the efficiency of power generation in microbial fuel cells (MFCs) for synthetic wastewater treatment, but also helping to reduce the period for MFCs start-up. The MFCs with anode modification in electrolyte of nitric acid performed the best, achieving a Coulombic efficiency enhancement of 71 %. As characterized, the electrochemical modification resulted in the decrease of the anode potential and internal resistance but the increase of current response and nitrogen-containing and oxygen-containing functional groups on the carbon surface, which might contribute to the enhancement on the performances of MFCs.

[Influence of the space layout of a surgical department on use efficiency].

PubMed

Weiss, G; von Baer, R; Riedl, S

2002-02-01

There is a growing gap between the rapidly increasing diagnostic and therapeutic opportunities and the patient demands on one side and the continuously declining hospital budgets on the other side. This gap forces hospitals to search for rationalization potentials and ways to increase their efficiency. It is well known that the operating theatre unit is one of the most important internal cost factors. Many reorganization projects therefore focus on operating theatres. In Germany, several alternative operating room layouts have been developed in order to reduce running und building costs and to reach a high degree of flexibility in their everyday use by means of an improved design. This article analyses and compares the classic operating room and four alternative layouts intended to make them suitable for reaching the promised objectives and, especially, achieving an economically run business management. Furthermore, preferred layouts for certain types of operations are recommended.

Integrated bioleaching of copper metal from waste printed circuit board-a comprehensive review of approaches and challenges.

PubMed

Awasthi, Abhishek Kumar; Zeng, Xianlai; Li, Jinhui

2016-11-01

Waste electrical and electronic equipment (e-waste) is the most rapidly growing waste stream in the world, and the majority of the residues are openly disposed of in developing countries. Waste printed circuit boards (WPCBs) make up the major portion of e-waste, and their informal recycling can cause environmental pollution and health risks. Furthermore, the conventional disposal and recycling techniques-mechanical treatments used to recover valuable metals, including copper-are not sustainable in the long term. Chemical leaching is rapid and efficient but causes secondary pollution. Bioleaching is a promising approach, eco-friendly and economically feasible, but it is slower process. This review considers the recycling potential of microbes and suggests an integrated bioleaching approach for Cu extraction and recovery from WPCBs. The proposed recycling system should be more effective, efficient and both technically and economically feasible.

Photoluminescence in Sm3+ doped Ba2P2O7 phosphor prepared by solution combustion method

NASA Astrophysics Data System (ADS)

Ghawade, Sonal P.; Deshmukh, Kavita A.; Dhoble, S. J.; Deshmukh, Abhay D.

2018-05-01

In this paper, Sm3+ doped Ba2P2O7 phosphors were synthesized via a Solution combustion method. The crystal structure of the phosphor was characterized by XRD. Orange-red emission was observed from these phosphors under near-ultraviolet (UV) excitation at 404 nm. The luminescence properties of the obtained phosphors were characterized by different techniques. The Ba2P2O7:Sm3+ phosphor can be efficiently excited by near-UV and blue light, and their emission spectrum consists of three emission peaks, at 564, 602, and 646 nm, respectively. Based on the results, the as prepared Ba2P2O7:Sm3+ phosphors are promising orange-red-emitting phosphors exhibit great potential may be applicable as a spectral convertor in c-Si solar cell to enhance the efficiency of solar cell in future.

Zr-doped TiO2 as a thermostabilizer in plasmon-enhanced dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Pasche, Anastasia; Grohe, Bernd; Mittler, Silvia; Charpentier, Paul A.

2017-07-01

Harvesting solar energy is a promising solution toward meeting the world's ever-growing energy demand. Dye-sensitized solar cells (DSSCs) are hybrid organic-inorganic solar cells with tremendous potential for commercial application, but they are plagued by inefficiency due to their poor sunlight absorption. Plasmonic silver nanoparticles (AgNPs) have been shown to enhance the absorptive properties of DSSCs, but their plasmonic resonance can cause thermal damage resulting in cell deterioration. Hence, the influence of Zr-doped TiO2 on the efficiency of plasmon-enhanced DSSCs was studied, showing that 5 mol.% Zr-doping of the photoactive TiO2 material can improve the photovoltaic performance of DSSCs by 44%. By examining three different DSSC designs, it became clear that the efficiency enhancing effect of Zr strongly depends on the proximity of the Zr-doped material to the plasmonic AgNPs.

An easily integrative and efficient micromixer and its application to the spectroscopic detection of glucose-catalyst reactions.

PubMed

Kim, D J; Oh, H J; Park, T H; Choo, J B; Lee, S H

2005-03-01

The focus of this paper is on the fabrication of a PDMS-based passive efficient micromixer to be easily integrated into the other on-chip microfluidic system. The mixing is achieved by "strong stretching and folding," which employs a three-dimensional microchannel structure. By the simultaneously vertical and transversal dispersion of fluids, strong advection is developed. Owing to this powerful mixing performance (more than 70% of the mixing is accomplished within 2.3 mm over a wide range of Reynold number (Re)), the smaller integrative mixer can be realized. The feasibility and the potential usefulness of an integrative micromixer were evaluated by incorporating two mixers into the microchannel for the spectroscopic detection of a glucose-catalyst reaction. The results demonstrate a promising performance for diverse applications in the assay or synthesis of biological or chemical materials.

A variational eigenvalue solver on a photonic quantum processor

PubMed Central

Peruzzo, Alberto; McClean, Jarrod; Shadbolt, Peter; Yung, Man-Hong; Zhou, Xiao-Qi; Love, Peter J.; Aspuru-Guzik, Alán; O’Brien, Jeremy L.

2014-01-01

Quantum computers promise to efficiently solve important problems that are intractable on a conventional computer. For quantum systems, where the physical dimension grows exponentially, finding the eigenvalues of certain operators is one such intractable problem and remains a fundamental challenge. The quantum phase estimation algorithm efficiently finds the eigenvalue of a given eigenvector but requires fully coherent evolution. Here we present an alternative approach that greatly reduces the requirements for coherent evolution and combine this method with a new approach to state preparation based on ansätze and classical optimization. We implement the algorithm by combining a highly reconfigurable photonic quantum processor with a conventional computer. We experimentally demonstrate the feasibility of this approach with an example from quantum chemistry—calculating the ground-state molecular energy for He–H+. The proposed approach drastically reduces the coherence time requirements, enhancing the potential of quantum resources available today and in the near future. PMID:25055053

Piezoelectric two-dimensional nanosheets/anionic layer heterojunction for efficient direct current power generation.

PubMed

Kim, Kwon-Ho; Kumar, Brijesh; Lee, Keun Young; Park, Hyun-Kyu; Lee, Ju-Hyuck; Lee, Hyun Hwi; Jun, Hoin; Lee, Dongyun; Kim, Sang-Woo

2013-01-01

Direct current (DC) piezoelectric power generator is promising for the miniaturization of a power package and self-powering of nanorobots and body-implanted devices. Hence, we report the first use of two-dimensional (2D) zinc oxide (ZnO) nanostructure and an anionic nanoclay layer to generate piezoelectric DC output power. The device, made from 2D nanosheets and an anionic nanoclay layer heterojunction, has potential to be the smallest size power package, and could be used to charge wireless nano/micro scale systems without the use of rectifier circuits to convert alternating current into DC to store the generated power. The combined effect of buckling behaviour of the ZnO nanosheets, a self-formed anionic nanoclay layer, and coupled semiconducting and piezoelectric properties of ZnO nanosheets contributes to efficient DC power generation. The networked ZnO nanosheets proved to be structurally stable under huge external mechanical loads.

Heavy Metal Phytoremediation: Microbial Indicators of Soil Health for the Assessment of Remediation Efficiency

NASA Astrophysics Data System (ADS)

Epelde, Lur; Ma Becerril, José; Alkorta, Itziar; Garbisu, Carlos

Phytoremediation is an effective, non-intrusive, inexpensive, aesthetically pleasing, socially accepted, promising phytotechnology for the remediation of polluted soils. The objective of any soil remediation process must be not only to remove the contaminant(s) from the soil but, most importantly, to restore the continued capacity of the soil to perform or function according to its potential (i.e., to recover soil health). Hence, indicators of soil health are needed to properly assess the efficiency of a phytoremediation process. Biological indicators of soil health, especially those related to the size, activity and diversity of the soil microbial communities, are becoming increasingly used, due to their sensitivity and capacity to provide information that integrates many environmental factors. In particular, microbial indicators of soil health are valid tools to evaluate the success of metal phytoremediation procedures such as phytoextraction and phytostabilization processes.

Nanophotonics-enabled solar membrane distillation for off-grid water purification.

PubMed

Dongare, Pratiksha D; Alabastri, Alessandro; Pedersen, Seth; Zodrow, Katherine R; Hogan, Nathaniel J; Neumann, Oara; Wu, Jinjian; Wang, Tianxiao; Deshmukh, Akshay; Elimelech, Menachem; Li, Qilin; Nordlander, Peter; Halas, Naomi J

2017-07-03

With more than a billion people lacking accessible drinking water, there is a critical need to convert nonpotable sources such as seawater to water suitable for human use. However, energy requirements of desalination plants account for half their operating costs, so alternative, lower energy approaches are equally critical. Membrane distillation (MD) has shown potential due to its low operating temperature and pressure requirements, but the requirement of heating the input water makes it energy intensive. Here, we demonstrate nanophotonics-enabled solar membrane distillation (NESMD), where highly localized photothermal heating induced by solar illumination alone drives the distillation process, entirely eliminating the requirement of heating the input water. Unlike MD, NESMD can be scaled to larger systems and shows increased efficiencies with decreased input flow velocities. Along with its increased efficiency at higher ambient temperatures, these properties all point to NESMD as a promising solution for household- or community-scale desalination.

Catalysis Meets Nonthermal Separation for the Production of (Alkyl)phenols and Hydrocarbons from Pyrolysis Oil.

PubMed

Cao, Zhengwen; Engelhardt, Jan; Dierks, Michael; Clough, Matthew T; Wang, Guang-Hui; Heracleous, Eleni; Lappas, Angelos; Rinaldi, Roberto; Schüth, Ferdi

2017-02-20

A simple and efficient hydrodeoxygenation strategy is described to selectively generate and separate high-value alkylphenols from pyrolysis bio-oil, produced directly from lignocellulosic biomass. The overall process is efficient and only requires low pressures of hydrogen gas (5 bar). Initially, an investigation using model compounds indicates that MoC x /C is a promising catalyst for targeted hydrodeoxygenation, enabling selective retention of the desired Ar-OH substituents. By applying this procedure to pyrolysis bio-oil, the primary products (phenol/4-alkylphenols and hydrocarbons) are easily separable from each other by short-path column chromatography, serving as potential valuable feedstocks for industry. The strategy requires no prior fractionation of the lignocellulosic biomass, no further synthetic steps, and no input of additional (e.g., petrochemical) platform molecules. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Expanding the Toolbox of Photoswitches for DNA Nanotechnology Using Arylazopyrazoles.

PubMed

Adam, Volker; Prusty, Deepak K; Centola, Mathias; Škugor, Marko; Hannam, Jeffrey S; Valero, Julián; Klöckner, Bernhard; Famulok, Michael

2018-01-24

Photoregulation is among the most promising tools for development of dynamic DNA nanosystems, due to its high spatiotemporal precision, biocompatibility, and ease of use. So far, azobenzene and its derivatives have shown high potential in photocontrolling DNA duplex hybridization by light-dependent photoisomerization. Despite many recent advances, obtaining sufficiently high photoswitching efficiency under conditions more suitable for work with DNA nanostructures are challenging. Here we introduce a pair of arylazopyrazoles as new photoswitches for efficient and reversible control of DNA hybridization achieved even at room temperature with a low number of required modifications. Their photophysical properties in the native state and in DNA strands result in near-quantitative isomerization rates by irradiation with UV and orange light. To demonstrate the applicability of these photoswitches, we have successfully applied one of them to open and close a DNA hairpin by light at room temperature. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Current State of Silicone-Based Dielectric Elastomer Transducers.

PubMed

Madsen, Frederikke B; Daugaard, Anders E; Hvilsted, Søren; Skov, Anne L

2016-03-01

Silicone elastomers are promising materials for dielectric elastomer transducers (DETs) due to their superior properties such as high efficiency, reliability and fast response times. DETs consist of thin elastomer films sandwiched between compliant electrodes, and they constitute an interesting class of transducer due to their inherent lightweight and potentially large strains. For the field to progress towards industrial implementation, a leap in material development is required, specifically targeting longer lifetime and higher energy densities to provide more efficient transduction at lower driving voltages. In this review, the current state of silicone elastomers for DETs is summarised and critically discussed, including commercial elastomers, composites, polymer blends, grafted elastomers and complex network structures. For future developments in the field it is essential that all aspects of the elastomer are taken into account, namely dielectric losses, lifetime and the very often ignored polymer network integrity and stability. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hollow fiber gas-liquid membrane contactors for acid gas capture: a review.

PubMed

Mansourizadeh, A; Ismail, A F

2009-11-15

Membrane contactors using microporous membranes for acid gas removal have been extensively reviewed and discussed. The microporous membrane acts as a fixed interface between the gas and the liquid phase without dispersing one phase into another that offers a flexible modular and energy efficient device. The gas absorption process can offer a high selectivity and a high driving force for transport even at low concentrations. Using hollow fiber gas-liquid membrane contactors is a promising alternative to conventional gas absorption systems for acid gas capture from gas streams. Important aspects of membrane contactor as an efficient energy devise for acid gas removal including liquid absorbents, membrane characteristics, combination of membrane and absorbent, mass transfer, membrane modules, model development, advantages and disadvantages were critically discussed. In addition, current status and future potential in research and development of gas-liquid membrane contactors for acid gas removal were also briefly discussed.

Fundamental rate-loss trade-off for the quantum internet

PubMed Central

Azuma, Koji; Mizutani, Akihiro; Lo, Hoi-Kwong

2016-01-01

The quantum internet holds promise for achieving quantum communication—such as quantum teleportation and quantum key distribution (QKD)—freely between any clients all over the globe, as well as for the simulation of the evolution of quantum many-body systems. The most primitive function of the quantum internet is to provide quantum entanglement or a secret key to two points efficiently, by using intermediate nodes connected by optical channels with each other. Here we derive a fundamental rate-loss trade-off for a quantum internet protocol, by generalizing the Takeoka–Guha–Wilde bound to be applicable to any network topology. This trade-off has essentially no scaling gap with the quantum communication efficiencies of protocols known to be indispensable to long-distance quantum communication, such as intercity QKD and quantum repeaters. Our result—putting a practical but general limitation on the quantum internet—enables us to grasp the potential of the future quantum internet. PMID:27886172

Stable Formamidinium-Based Perovskite Solar Cells via In Situ Grain Encapsulation

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

Zhu, Kai; Li, Zhen; Yang, Ye

Formamidinium (FA)-based lead iodide perovskites have emerged as the most promising light-absorber materials in the prevailing perovskite solar cells (PSCs). However, they suffer from the phase-instability issue in the ambient atmosphere, which is holding back the realization of the full potential of FA-based PSCs in the context of high efficiency and stability. Herein, the tetraethylorthosilicate hydrolysis process is integrated with the solution crystallization of FA-based perovskites, forming a new film structure with individual perovskite grains encapsulated by amorphous silica layers that are in situ formed at the nanoscale. The silica not only protects perovskite grains from the degradation but alsomore » enhances the charge-carrier dynamics of perovskite films. The underlying mechanism is discussed using a joint experiment-theory approach. Through this in situ grain encapsulation method, PSCs show an efficiency close to 20% with an impressive 97% retention after 1000-h storage under ambient conditions.« less

Nanophotonics-enabled solar membrane distillation for off-grid water purification

PubMed Central

Dongare, Pratiksha D.; Alabastri, Alessandro; Pedersen, Seth; Zodrow, Katherine R.; Hogan, Nathaniel J.; Neumann, Oara; Wu, Jinjian; Wang, Tianxiao; Deshmukh, Akshay; Elimelech, Menachem; Li, Qilin; Nordlander, Peter; Halas, Naomi J.

2017-01-01

With more than a billion people lacking accessible drinking water, there is a critical need to convert nonpotable sources such as seawater to water suitable for human use. However, energy requirements of desalination plants account for half their operating costs, so alternative, lower energy approaches are equally critical. Membrane distillation (MD) has shown potential due to its low operating temperature and pressure requirements, but the requirement of heating the input water makes it energy intensive. Here, we demonstrate nanophotonics-enabled solar membrane distillation (NESMD), where highly localized photothermal heating induced by solar illumination alone drives the distillation process, entirely eliminating the requirement of heating the input water. Unlike MD, NESMD can be scaled to larger systems and shows increased efficiencies with decreased input flow velocities. Along with its increased efficiency at higher ambient temperatures, these properties all point to NESMD as a promising solution for household- or community-scale desalination. PMID:28630307

Nutraceutical phycocyanin nanoformulation for efficient drug delivery of paclitaxel in human glioblastoma U87MG cell line

NASA Astrophysics Data System (ADS)

Agrawal, Madhunika; Yadav, Sanjeev Kumar; Agrawal, Satyam Kumar; Karmakar, Surajit

2017-08-01

To enhance the therapeutic efficacy of chemotherapy on glioblastoma U87MG cell line, paclitaxel-loaded phycocyanin nanoparticles (PTX-PcNPs) were prepared by modified desolvation process. PTX-PcNPs were characterised in terms of size, zeta potential, drug loading efficiency and drug release. Confocal laser scanning microscopy showed PTX-PcNPs could be internalised by U87MG cells. The anti-cancer activity was investigated in vitro by 3-(4,5-dimethylthizol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with and without photodynamic therapy. It was observed that formulation could significantly inhibit growth of U87MG cells as compared to PTX alone and also induced apoptosis, which was evidenced by presence of apoptotic bodies and nuclear fragmentation in treated cells. The present study suggests that PTX-PcNPs can act as a promising drug delivery system for cancer treatment. [Figure not available: see fulltext.

Graphene-based photovoltaic cells for near-field thermal energy conversion

PubMed Central

Messina, Riccardo; Ben-Abdallah, Philippe

2013-01-01

Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat. PMID:23474891

Precision Viticulture from Multitemporal, Multispectral Very High Resolution Satellite Data

NASA Astrophysics Data System (ADS)

Kandylakis, Z.; Karantzalos, K.

2016-06-01

In order to exploit efficiently very high resolution satellite multispectral data for precision agriculture applications, validated methodologies should be established which link the observed reflectance spectra with certain crop/plant/fruit biophysical and biochemical quality parameters. To this end, based on concurrent satellite and field campaigns during the veraison period, satellite and in-situ data were collected, along with several grape samples, at specific locations during the harvesting period. These data were collected for a period of three years in two viticultural areas in Northern Greece. After the required data pre-processing, canopy reflectance observations, through the combination of several vegetation indices were correlated with the quantitative results from the grape/must analysis of grape sampling. Results appear quite promising, indicating that certain key quality parameters (like brix levels, total phenolic content, brix to total acidity, anthocyanin levels) which describe the oenological potential, phenolic composition and chromatic characteristics can be efficiently estimated from the satellite data.

Fundamental rate-loss trade-off for the quantum internet.

PubMed

Azuma, Koji; Mizutani, Akihiro; Lo, Hoi-Kwong

2016-11-25

The quantum internet holds promise for achieving quantum communication-such as quantum teleportation and quantum key distribution (QKD)-freely between any clients all over the globe, as well as for the simulation of the evolution of quantum many-body systems. The most primitive function of the quantum internet is to provide quantum entanglement or a secret key to two points efficiently, by using intermediate nodes connected by optical channels with each other. Here we derive a fundamental rate-loss trade-off for a quantum internet protocol, by generalizing the Takeoka-Guha-Wilde bound to be applicable to any network topology. This trade-off has essentially no scaling gap with the quantum communication efficiencies of protocols known to be indispensable to long-distance quantum communication, such as intercity QKD and quantum repeaters. Our result-putting a practical but general limitation on the quantum internet-enables us to grasp the potential of the future quantum internet.

Graphene-based photovoltaic cells for near-field thermal energy conversion.

PubMed

Messina, Riccardo; Ben-Abdallah, Philippe

2013-01-01

Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat.

Cotton-textile-enabled flexible self-sustaining power packs via roll-to-roll fabrication

PubMed Central

Gao, Zan; Bumgardner, Clifton; Song, Ningning; Zhang, Yunya; Li, Jingjing; Li, Xiaodong

2016-01-01

With rising energy concerns, efficient energy conversion and storage devices are required to provide a sustainable, green energy supply. Solar cells hold promise as energy conversion devices due to their utilization of readily accessible solar energy; however, the output of solar cells can be non-continuous and unstable. Therefore, it is necessary to combine solar cells with compatible energy storage devices to realize a stable power supply. To this end, supercapacitors, highly efficient energy storage devices, can be integrated with solar cells to mitigate the power fluctuations. Here, we report on the development of a solar cell-supercapacitor hybrid device as a solution to this energy requirement. A high-performance, cotton-textile-enabled asymmetric supercapacitor is integrated with a flexible solar cell via a scalable roll-to-roll manufacturing approach to fabricate a self-sustaining power pack, demonstrating its potential to continuously power future electronic devices. PMID:27189776

Variable speed control in wells turbine-based oscillating water column devices: optimum rotational speed

NASA Astrophysics Data System (ADS)

Lekube, J.; Garrido, A. J.; Garrido, I.

2018-03-01

The effects of climate change and global warming reveal the need to find alternative sources of clean energy. In this sense, wave energy power plants, and in particular Oscillating Water Column (OWC) devices, offer a huge potential of energy harnessing. Nevertheless, the conversion systems have not reached a commercially mature stage yet so as to compete with conventional power plants. At this point, the use of new control methods over the existing technology arises as a doable way to improve the efficiency of the system. Due to the non-uniform response that the turbine shows to the rotational speed variation, the speed control of the turbo-generator may offer a feasible solution for efficiency improvement during the energy conversion. In this context, a novel speed control approach for OWC systems is presented in this paper, demonstrating its goodness and affording promising results when particularized to the Mutriku’s wave power plant.

Microbial fuel cells: recent developments in design and materials

NASA Astrophysics Data System (ADS)

Bhargavi, G.; Venu, V.; Renganathan, S.

2018-03-01

Microbial Fuel Cells (MFCs) are the promising devices which can produce electricity by anaerobic fermentation of organic / inorganic matter from easily metabolized biomass to complex wastewater using microbes as biocatalysts. MFC technology has been found as a potential technology for electricity generation and concomitant wastewater treatment. However, the high cost of the components and low efficiency are barricading the commercialization of MFC when compared with other energy generating systems. The performance of an MFC is largely relying on the reactor design and electrode materials. On the way to improve the efficiency of an MFC, tremendous exercises have been carried out to explore new electrode materials and reactor designs in recent decades. The current review is excogitated to amass the progress in design and electrode materials, which could bolster further investigations on MFCs to improve their performance, mitigate the cost and successful implementation of technology in field applications as well.

High-efficiency and high-power rechargeable lithium–sulfur dioxide batteries exploiting conventional carbonate-based electrolytes

PubMed Central

Park, Hyeokjun; Lim, Hee-Dae; Lim, Hyung-Kyu; Seong, Won Mo; Moon, Sehwan; Ko, Youngmin; Lee, Byungju; Bae, Youngjoon; Kim, Hyungjun; Kang, Kisuk

2017-01-01

Shedding new light on conventional batteries sometimes inspires a chemistry adoptable for rechargeable batteries. Recently, the primary lithium-sulfur dioxide battery, which offers a high energy density and long shelf-life, is successfully renewed as a promising rechargeable system exhibiting small polarization and good reversibility. Here, we demonstrate for the first time that reversible operation of the lithium-sulfur dioxide battery is also possible by exploiting conventional carbonate-based electrolytes. Theoretical and experimental studies reveal that the sulfur dioxide electrochemistry is highly stable in carbonate-based electrolytes, enabling the reversible formation of lithium dithionite. The use of the carbonate-based electrolyte leads to a remarkable enhancement of power and reversibility; furthermore, the optimized lithium-sulfur dioxide battery with catalysts achieves outstanding cycle stability for over 450 cycles with 0.2 V polarization. This study highlights the potential promise of lithium-sulfur dioxide chemistry along with the viability of conventional carbonate-based electrolytes in metal-gas rechargeable systems. PMID:28492225

Nano-vectors for efficient liver specific gene transfer

PubMed Central

Pathak, Atul; Vyas, Suresh P; Gupta, Kailash C

2008-01-01

Recent progress in nanotechnology has triggered the site specific drug/gene delivery research and gained wide acknowledgment in contemporary DNA therapeutics. Amongst various organs, liver plays a crucial role in various body functions and in addition, the site is a primary location of metastatic tumor growth. In past few years, a plethora of nano-vectors have been developed and investigated to target liver associated cells through receptor mediated endocytosis. This emerging paradigm in cellular drug/gene delivery provides promising approach to eradicate genetic as well as acquired diseases affecting the liver. The present review provides a comprehensive overview of potential of various delivery systems, viz., lipoplexes, liposomes, polyplexes, nanoparticles and so forth to selectively relocate foreign therapeutic DNA into liver specific cell type via the receptor mediated endocytosis. Various receptors like asialoglycoprotein receptors (ASGP-R) provide unique opportunity to target liver parenchymal cells. The results obtained so far reveal tremendous promise and offer enormous options to develop novel DNA-based pharmaceuticals for liver disorders in near future. PMID:18488414

Development of Inhalable Superparamagnetic Iron Oxide Nanoparticles (SPIONs) in Microparticulate System for Antituberculosis Drug Delivery.

PubMed

Miranda, Margarida S; Rodrigues, Márcia T; Domingues, Rui M A; Costa, Rui R; Paz, Elvira; Rodríguez-Abreu, Carlos; Freitas, Paulo; Almeida, Bernardo G; Carvalho, Maria Alice; Gonçalves, Carine; Ferreira, Catarina M; Torrado, Egídio; Reis, Rui L; Pedrosa, Jorge; Gomes, Manuela E

2018-05-23

Tuberculosis (TB) is an infectious disease which affects millions of people worldwide. Inhalable polymeric dry powders are promising alternatives as anti-TB drug carriers to the alveoli milieu and infected macrophages, with potential to significantly improve the therapeutics efficiency. Here, the development of a magnetically responsive microparticulate system for pulmonary delivery of an anti-TB drug candidate (P3) is reported. Microparticles (MPs) are developed based on a cast method using calcium carbonate sacrificial templates and incorporate superparamagnetic iron oxide nanoparticles to concentrate MPs in alveoli and enable drug on demand release upon actuation of an external alternate magnetic field (AMF). The MPs are shown to be suitable for P3 delivery to the lower airways and for alveolar macrophage phagocytosis. The developed MPs reveal unique and promising features to be used as an inhalable dry powder allowing the AMF control over dosage and frequency of drug delivery anticipating improved TB treatments. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elasticity of human embryonic stem cells as determined by atomic force microscopy.

PubMed

Kiss, Robert; Bock, Henry; Pells, Steve; Canetta, Elisabetta; Adya, Ashok K; Moore, Andrew J; De Sousa, Paul; Willoughby, Nicholas A

2011-10-01

The expansive growth and differentiation potential of human embryonic stem cells (hESCs) make them a promising source of cells for regenerative medicine. However, this promise is off set by the propensity for spontaneous or uncontrolled differentiation to result in heterogeneous cell populations. Cell elasticity has recently been shown to characterize particular cell phenotypes, with undifferentiated and differentiated cells sometimes showing significant differences in their elasticities. In this study, we determined the Young's modulus of hESCs by atomic force microscopy using a pyramidal tip. Using this method we are able to take point measurements of elasticity at multiple locations on a single cell, allowing local variations due to cell structure to be identified. We found considerable differences in the elasticity of the analyzed hESCs, reflected by a broad range of Young's modulus (0.05-10 kPa). This surprisingly high variation suggests that elasticity could serve as the basis of a simple and efficient large scale purification/separation technique to discriminate subpopulations of hESCs.

Engineering of Genetically Arrested Parasites (GAPs) For a Precision Malaria Vaccine.

PubMed

Kreutzfeld, Oriana; Müller, Katja; Matuschewski, Kai

2017-01-01

Continuous stage conversion and swift changes in the antigenic repertoire in response to acquired immunity are hallmarks of complex eukaryotic pathogens, including Plasmodium species, the causative agents of malaria. Efficient elimination of Plasmodium liver stages prior to blood infection is one of the most promising malaria vaccine strategies. Here, we describe different genetically arrested parasites (GAPs) that have been engineered in Plasmodium berghei, P. yoelii and P. falciparum and compare their vaccine potential. A better understanding of the immunological mechanisms of prime and boost by arrested sporozoites and experimental strategies to enhance vaccine efficacy by further engineering existing GAPs into a more immunogenic form hold promise for continuous improvements of GAP-based vaccines. A critical hurdle for vaccines that elicit long-lasting protection against malaria, such as GAPs, is safety and efficacy in vulnerable populations. Vaccine research should focus on solutions toward turning malaria into a vaccine-preventable disease, which would offer an exciting new path of malaria control.

Pluripotent Stem Cells in Research and Treatment of Hemoglobinopathies

PubMed Central

Arora, Natasha; Daley, George Q.

2012-01-01

Pluripotent stem cells (PSCs) hold great promise for research and treatment of hemoglobinopathies. In principle, patient-specific induced pluripotent stem cells could be derived from a blood sample, genetically corrected to repair the disease-causing mutation, differentiated into hematopoietic stem cells (HSCs), and returned to the patient to provide a cure through autologous gene and cell therapy. However, there are many challenges at each step of this complex treatment paradigm. Gene repair is currently inefficient in stem cells, but use of zinc finger nucleases and transcription activator-like effector nucleases appear to be a major advance. To date, no successful protocol exists for differentiating PSCs into definitive HSCs. PSCs can be directly differentiated into primitive red blood cells, but not yet in sufficient numbers to enable treating patients, and the cost of clinical scale differentiation is prohibitively expensive with current differentiation methods and efficiencies. Here we review the progress, promise, and remaining hurdles in realizing the potential of PSCs for cell therapy. PMID:22474618

Systematic review of behaviour change techniques to promote participation in physical activity among people with dementia.

PubMed

Nyman, Samuel R; Adamczewska, Natalia; Howlett, Neil

2018-02-01

The objective of this study was to systematically review the evidence for the potential promise of behaviour change techniques (BCTs) to increase physical activity among people with dementia (PWD). PsychINFO, MEDLINE, CINAHL, and the Cochrane Central Register of Controlled Trials databases were searched 01/01/2000-01/12/2016. Randomized controlled/quasi-randomized trials were included if they recruited people diagnosed/suspected to have dementia, used at least one BCT in the intervention arm, and had at least one follow-up measure of physical activity/adherence. Studies were appraised using the Cochrane Collaboration Risk of Bias Tool, and BCTs were coded using Michie et al., 2013, Annals of Behavioral Medicine, 46, 81. taxonomy. Intervention findings were narratively synthesized as either 'very promising', 'quite promising', or 'non-promising', and BCTs were judged as having potential promise if they featured in at least twice as many very/quite promising than non-promising interventions (as per Gardner et al., 2016, Health Psychology Review, 10, 89). Nineteen articles from nine trials reported physical activity findings on behavioural outcomes (two very promising, one quite promising, and two non-promising) or intervention adherence (one quite promising and four non-promising). Thirteen BCTs were used across the interventions. While no BCT had potential promise to increase intervention adherence, three BCTs had potential promise for improving physical activity behaviour outcomes: goal setting (behaviour), social support (unspecified), and using a credible source. Three BCTs have potential promise for use in future interventions to increase physical activity among PWD. Statement of contribution What is already known on this subject? While physical activity is a key lifestyle factor to enhance and maintain health and wellbeing amongst the general population, adults rarely participate in sufficient levels to obtain these benefits. Systematic reviews suggest that specific behaviour change techniques can increase physical activity, although one review suggested that self-regulatory techniques may be counterproductive when promoting physical activity among older people. Until now, no systematic review has been conducted to assess which behaviour change techniques may be associated with greater participation in physical activity among people with dementia. What does this study add? Interventions showed mixed promise for increasing physical activity and little effect on participant adherence. Goal setting (behaviour), social support (unspecified), and using a credible source are promising approaches. No technique showed promise for increasing adherence to physical activity interventions among people with dementia. © 2017 The British Psychological Society.

Near-infrared roll-off-free electroluminescence from highly stable diketopyrrolopyrrole light emitting diodes

PubMed Central

Sassi, Mauro; Buccheri, Nunzio; Rooney, Myles; Botta, Chiara; Bruni, Francesco; Giovanella, Umberto; Brovelli, Sergio; Beverina, Luca

2016-01-01

Organic light emitting diodes (OLEDs) operating in the near-infrared spectral region are gaining growing relevance for emerging photonic technologies, such as lab-on-chip platforms for medical diagnostics, flexible self-medicated pads for photodynamic therapy, night vision and plastic-based telecommunications. The achievement of efficient near-infrared electroluminescence from solution-processed OLEDs is, however, an open challenge due to the low photoluminescence efficiency of most narrow-energy-gap organic emitters. Diketopyrrolopyrrole-boron complexes are promising candidates to overcome this limitation as they feature extremely high photoluminescence quantum yield in the near-infrared region and high chemical stability. Here, by incorporating suitably functionalized diketopyrrolopyrrole derivatives emitting at ~760 nm in an active matrix of poly(9,9-dioctylfluorene-alt-benzothiadiazole) and without using complex light out-coupling or encapsulation strategies, we obtain all-solution-processed NIR-OLEDs with external quantum efficiency as high as 0.5%. Importantly, our test-bed devices show no efficiency roll-off even for high current densities and high operational stability, retaining over 50% of the initial radiant emittance for over 50 hours of continuous operation at 10 mA/cm2, which emphasizes the great applicative potential of the proposed strategy. PMID:27677240

Enhanced xylene removal by photocatalytic oxidation using fiber-illuminated honeycomb reactor at ppb level.

PubMed

Wu, Yi-Ting; Yu, Yi-Hui; Nguyen, Van-Huy; Lu, Kung-Te; Wu, Jeffrey Chi-Sheng; Chang, Luh-Maan; Kuo, Chi-Wen

2013-11-15

The removal of volatile organic compounds (VOCs) at ppb level is one of the most critical challenges in clean rooms for the semiconductor industry. Photocatalytic oxidation is an innovative and promising technology for ppb-level VOCs degradation. We have designed a fiber-illuminated honeycomb reactor (FIHR) in which the removal efficiency of m-xylene is significantly enhanced to 96.5% as compared to 22.0% for UV irradiation only. The results indicate that photocatalysts not only play the role to substantially oxidize m-xylene, but also alter the chemical properties of xylene under UV illumination. Using the FIHR with Mn-TiO2 photocatalyst not only increased the m-xylene removal efficiency, but also increased the CO2 selectivity. Interestingly, Mn-TiO2 in FIHR also showed a very good reusability, 93% removal efficiency was still achieved in 72-h in reaction. Thus, the FIHR gave very high removal efficiency for xylene at ppb level under room temperature. The FIHR has great potential application in the clean room for the air purification system in the future. Copyright © 2013 Elsevier B.V. All rights reserved.

Enhanced broadband absorption in nanowire arrays with integrated Bragg reflectors

NASA Astrophysics Data System (ADS)

Aghaeipour, Mahtab; Pettersson, Håkan

2018-05-01

A near-unity unselective absorption spectrum is desirable for high-performance photovoltaics. Nanowire (NW) arrays are promising candidates for efficient solar cells due to nanophotonic absorption resonances in the solar spectrum. The absorption spectra, however, display undesired dips between the resonance peaks. To achieve improved unselective broadband absorption, we propose to enclose distributed Bragg reflectors (DBRs) in the bottom and top parts of indium phosphide (InP) NWs, respectively. We theoretically show that by enclosing only two periods of In0.56Ga0.44As/InP DBRs, an unselective 78% absorption efficiency (72% for NWs without DBRs) is obtained at normal incidence in the spectral range from 300 nm to 920 nm. Under oblique light incidence, the absorption efficiency is enhanced up to about 85% at an incidence angle of 50°. By increasing the number of DBR periods from two to five, the absorption efficiency is further enhanced up to 95% at normal incidence. In this work, we calculated optical spectra for InP NWs, but the results are expected to be valid for other direct band gap III-V semiconductor materials. We believe that our proposed idea of integrating DBRs in NWs offers great potential for high-performance photovoltaic applications.

Dimethyl ether (DME) as an alternative fuel

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.; Greene, Howard L.

With ever growing concerns on environmental pollution, energy security, and future oil supplies, the global community is seeking non-petroleum based alternative fuels, along with more advanced energy technologies (e.g., fuel cells) to increase the efficiency of energy use. The most promising alternative fuel will be the fuel that has the greatest impact on society. The major impact areas include well-to-wheel greenhouse gas emissions, non-petroleum feed stocks, well-to-wheel efficiencies, fuel versatility, infrastructure, availability, economics, and safety. Compared to some of the other leading alternative fuel candidates (i.e., methane, methanol, ethanol, and Fischer-Tropsch fuels), dimethyl ether appears to have the largest potential impact on society, and should be considered as the fuel of choice for eliminating the dependency on petroleum. DME can be used as a clean high-efficiency compression ignition fuel with reduced NO x, SO x, and particulate matter, it can be efficiently reformed to hydrogen at low temperatures, and does not have large issues with toxicity, production, infrastructure, and transportation as do various other fuels. The literature relevant to DME use is reviewed and summarized to demonstrate the viability of DME as an alternative fuel.

A review of advanced turboprop transport aircraft

NASA Astrophysics Data System (ADS)

Lange, Roy H.

The application of advanced technologies shows the potential for significant improvement in the fuel efficiency and operating costs of future transport aircraft envisioned for operation in the 1990s time period. One of the more promising advanced technologies is embodied in an advanced turboprop concept originated by Hamilton Standard and NASA and known as the propfan. The propfan concept features a highly loaded multibladed, variable pitch propeller geared to a high pressure ratio gas turbine engine. The blades have high sweepback and advanced airfoil sections to achieve 80 percent propulsive efficiency at M=0.80 cruise speed. Aircraft system studies have shown improvements in fuel efficiency of 15-20 percent for propfan advanced transport aircraft as compared to equivalent turbofan transports. Beginning with the Lockheed C-130 and Electra turboprop aircraft, this paper presents an overview of the evolution of propfan aircraft design concepts and system studies. These system studies include possible civil and military transport applications and data on the performance, community and far-field noise characteristics and operating costs of propfan aircraft design concepts. NASA Aircraft Energy Efficiency (ACEE) program propfan projects with industry are reviewed with respect to system studies of propfan aircraft and recommended flight development programs.

High-Efficiency Nanowire Solar Cells with Omnidirectionally Enhanced Absorption Due to Self-Aligned Indium-Tin-Oxide Mie Scatterers.

PubMed

van Dam, Dick; van Hoof, Niels J J; Cui, Yingchao; van Veldhoven, Peter J; Bakkers, Erik P A M; Gómez Rivas, Jaime; Haverkort, Jos E M

2016-12-27

Photovoltaic cells based on arrays of semiconductor nanowires promise efficiencies comparable or even better than their planar counterparts with much less material. One reason for the high efficiencies is their large absorption cross section, but until recently the photocurrent has been limited to less than 70% of the theoretical maximum. Here we enhance the absorption in indium phosphide (InP) nanowire solar cells by employing broadband forward scattering of self-aligned nanoparticles on top of the transparent top contact layer. This results in a nanowire solar cell with a photovoltaic conversion efficiency of 17.8% and a short-circuit current of 29.3 mA/cm 2 under 1 sun illumination, which is the highest reported so far for nanowire solar cells and among the highest reported for III-V solar cells. We also measure the angle-dependent photocurrent, using time-reversed Fourier microscopy, and demonstrate a broadband and omnidirectional absorption enhancement for unpolarized light up to 60° with a wavelength average of 12% due to Mie scattering. These results unambiguously demonstrate the potential of semiconductor nanowires as nanostructures for the next generation of photovoltaic devices.

Silver oxide nanocrystals anchored on titanate nanotubes and nanofibers: promising candidates for entrapment of radioactive iodine anions.

PubMed

Yang, Dongjiang; Liu, Hongwei; Liu, Long; Sarina, Sarina; Zheng, Zhanfeng; Zhu, Huaiyong

2013-11-21

Iodine radioisotopes are released into the environment by the nuclear industry and medical research institutions using radioactive materials. The (129)I(-) anion is one of the more mobile radioactive species due to a long half-life, and it is a great challenge to design long-term management solutions for such radioactive waste. In this study, a new adsorbent structure with the potential to efficiently remove radioactive iodine anions (I(-)) from water is devised: silver oxide (Ag2O) nanocrystals firmly anchored on the surface of titanate nanotubes and nanofibers via coherent interfaces between Ag2O and titanate phases. I(-) anions in fluids can easily access the Ag2O nanocrystals and be efficiently trapped by forming AgI precipitate that firmly attaches to the adsorbent. Due to their one-dimensional morphology, the new adsorbents can be readily dispersed in liquids and easily separated after purification; and the adsorption beds loaded with the adsorbents can permit high flux. This significantly enhances the adsorption efficiency and reduces the separation costs. The proposed structure reveals a new direction in developing efficient adsorbents for the removal of radioactive anions from wastewater.

Enhanced H-filter based on Fåhræus-Lindqvist effect for efficient and robust dialysis without membrane

PubMed Central

Zheng, Wei-Chao; Xie, Rui; He, Li-Qun; Xi, Yue-Heng; Liu, Ying-Mei; Meng, Zhi-Jun; Wang, Wei; Ju, Xiao-Jie; Chen, Gang; Chu, Liang-Yin

2015-01-01

A novel microfluidic device for highly efficient and robust dialysis without membrane is highly desired for the development of portable or wearable microdialyzer. Here we report an enhanced H-filter with pillar array based on Fåhræus-Lindqvist effect (F-L effect) for highly efficient and robust membraneless dialysis of simplified blood for the first time. The H-filter employs two fluids laminarly flowing in the microchannel for continuously membraneless dialysis. With pillar array in the microchannel, the two laminar flows, with one containing blood cells and small molecules and another containing dialyzate solution, can form a cell-free layer at the interface as selective zones for separation. This provides enhanced mixing yet extremely low shear for extraction of small molecules from the blood-cell-containing flow into the dialyzate flow, resulting in robust separation with reduced cell loss and improved efficiency. We demonstrate this by first using Chlorella pyrenoidosa as model cells to quantitatively study the separation performances, and then using simplified human blood for dialysis. The advanced H-filter, with highly efficient and robust performance for membraneless dialysis, shows great potential as promising candidate for rapid blood analysis/separation, and as fundamental structure for portable dialyzer. PMID:26339313

Highly Efficient Visible Colloidal Lead-Halide Perovskite Nanocrystal Light-Emitting Diodes

NASA Astrophysics Data System (ADS)

Yan, Fei; Xing, Jun; Xing, Guichuan; Quan, Lina; Tan, Swee Tiam; Zhao, Jiaxin; Su, Rui; Zhang, Lulu; Chen, Shi; Zhao, Yawen; Huan, Alfred; Sargent, Edward H.; Xiong, Qihua; Demir, Hilmi Volkan

2018-05-01

Lead-halide perovskites have been attracting attention for potential use in solid-state lighting. Following the footsteps of solar cells, the field of perovskite light-emitting diodes (PeLEDs) has been growing rapidly. Their application prospects in lighting, however, remain still uncertain due to a variety of shortcomings in device performance including their limited levels of luminous efficiency achievable thus far. Here we show high-efficiency PeLEDs based on colloidal perovskite nanocrystals (PeNCs) synthesized at room temperature possessing dominant first-order excitonic radiation (enabling a photoluminescence quantum yield of 71% in solid film), unlike in the case of bulk perovskites with slow electron-hole bimolecular radiative recombination (a second-order process). In these PeLEDs, by reaching charge balance in the recombination zone, we find that the Auger nonradiative recombination, with its significant role in emission quenching, is effectively suppressed in low driving current density range. In consequence, these devices reach a record high maximum external quantum efficiency of 12.9% reported to date and an unprecedentedly high power efficiency of 30.3 lm W-1 at luminance levels above 1000 cd m-2 as required for various applications. These findings suggest that, with feasible levels of device performance, the PeNCs hold great promise for their use in LED lighting and displays.

Highly Efficient Broadband Multiplexed Millimeter-Wave Vortices from Metasurface-Enabled Transmit-Arrays of Subwavelength Thickness

NASA Astrophysics Data System (ADS)

Jiang, Zhi Hao; Kang, Lei; Hong, Wei; Werner, Douglas H.

2018-06-01

Structured electromagnetic waves carrying nonvanishing orbital angular momentum (OAM) have recently opened up alternative frontiers in the field of wave physics, holding great promise for a wide range of potential applications. By leveraging geometric phases originating from spin-to-orbital interactions, spin-dependent wave phenomena can be created, leading to a more versatile realm of dispersionless wave-front manipulation. However, the currently available transmissive vortex-beam generators suffer from a narrow bandwidth, require an optically thick device profile, or are limited by a low efficiency, severely restricting their integration into systems and/or widespread usage for practical applications. We present the design methodology and a physical analysis and complete experimental characterization of a class of millimeter-wave Pancharatnam-Berry transmit-arrays with a thickness of about λ0/3 , which enables highly efficient generation and separation of spin-controlled vortex beams over a broad bandwidth, achieving an unprecedented peak efficiency of 88% for a single vortex beam and 71% for dual vortex beams. The proposed transmit-array, which is capable of providing two-dimensional OAM multiplexing and demultiplexing without normal-mode background interference, overcomes all previous roadblocks and paves the way for high-efficiency electromagnetic vortex-beam generation as well as other wave-front-shaping devices from microwave frequencies to optical wavelengths.

Enhanced H-filter based on Fåhræus-Lindqvist effect for efficient and robust dialysis without membrane.

PubMed

Zheng, Wei-Chao; Xie, Rui; He, Li-Qun; Xi, Yue-Heng; Liu, Ying-Mei; Meng, Zhi-Jun; Wang, Wei; Ju, Xiao-Jie; Chen, Gang; Chu, Liang-Yin

2015-07-01

A novel microfluidic device for highly efficient and robust dialysis without membrane is highly desired for the development of portable or wearable microdialyzer. Here we report an enhanced H-filter with pillar array based on Fåhræus-Lindqvist effect (F-L effect) for highly efficient and robust membraneless dialysis of simplified blood for the first time. The H-filter employs two fluids laminarly flowing in the microchannel for continuously membraneless dialysis. With pillar array in the microchannel, the two laminar flows, with one containing blood cells and small molecules and another containing dialyzate solution, can form a cell-free layer at the interface as selective zones for separation. This provides enhanced mixing yet extremely low shear for extraction of small molecules from the blood-cell-containing flow into the dialyzate flow, resulting in robust separation with reduced cell loss and improved efficiency. We demonstrate this by first using Chlorella pyrenoidosa as model cells to quantitatively study the separation performances, and then using simplified human blood for dialysis. The advanced H-filter, with highly efficient and robust performance for membraneless dialysis, shows great potential as promising candidate for rapid blood analysis/separation, and as fundamental structure for portable dialyzer.

Benefit or burden? Perceptions of energy efficiency efforts among low-income housing residents in New York City.

PubMed

Hernández, Diana; Phillips, Douglas

2015-07-01

Low-income households contend with high energy costs and poor thermal comfort due to poor structural conditions and energy inefficiencies in their homes. Energy efficiency upgrades can potentially reduce energy expenses and improve thermal comfort, while also addressing problematic issues in the home environment. The present mixed method pilot study explored the impacts of energy efficiency upgrades in 20 households in a low-income community in New York City. Surveys and interviews were administered to the heads of household in a variety of housing types. Interviews were also conducted with landlords of buildings that had recently undergone upgrades. Findings indicate that energy efficiency measures resulted in improved thermal comfort, enhanced health and safety and reduced energy costs. Participants reported largely positive experiences with the upgrades, resulting in direct and indirect benefits. However, results also indicate negative consequences associated with the upgrades and further illustrate that weatherization alone was insufficient to address all of the issues facing low-income households. Moreover, qualitative results revealed differing experiences of low-income renters compared to homeowners. Overall, energy efficiency upgrades are a promising intervention to mitigate the energy and structurally related challenges facing low-income households, but larger scale research is needed to capture the long-term implications of these upgrades.

Benefit or burden? Perceptions of energy efficiency efforts among low-income housing residents in New York City☆

PubMed Central

Hernández, Diana; Phillips, Douglas

2016-01-01

Low-income households contend with high energy costs and poor thermal comfort due to poor structural conditions and energy inefficiencies in their homes. Energy efficiency upgrades can potentially reduce energy expenses and improve thermal comfort, while also addressing problematic issues in the home environment. The present mixed method pilot study explored the impacts of energy efficiency upgrades in 20 households in a low-income community in New York City. Surveys and interviews were administered to the heads of household in a variety of housing types. Interviews were also conducted with landlords of buildings that had recently undergone upgrades. Findings indicate that energy efficiency measures resulted in improved thermal comfort, enhanced health and safety and reduced energy costs. Participants reported largely positive experiences with the upgrades, resulting in direct and indirect benefits. However, results also indicate negative consequences associated with the upgrades and further illustrate that weatherization alone was insufficient to address all of the issues facing low-income households. Moreover, qualitative results revealed differing experiences of low-income renters compared to homeowners. Overall, energy efficiency upgrades are a promising intervention to mitigate the energy and structurally related challenges facing low-income households, but larger scale research is needed to capture the long-term implications of these upgrades. PMID:27054092

Lighting and vegetation for energy-efficient and safe roadway travel : final report (1,015.15 KB)

DOT National Transportation Integrated Search

2009-05-01

The objective of the present study was to identify and evaluate promising approaches to incorporating : lighting and vegetation along roadways with the purpose of identifying the most promising application that : could be incorporated into a demonstr...

Combining a CD20 Chimeric Antigen Receptor and an Inducible Caspase 9 Suicide Switch to Improve the Efficacy and Safety of T Cell Adoptive Immunotherapy for Lymphoma

PubMed Central

Budde, Lihua E.; Berger, Carolina; Lin, Yukang; Wang, Jinjuan; Lin, Xubin; Frayo, Shani E.; Brouns, Shaunda A.; Spencer, David M.; Till, Brian G.; Jensen, Michael C.; Riddell, Stanley R.; Press, Oliver W.

2013-01-01

Modification of T cells with chimeric antigen receptors (CAR) has emerged as a promising treatment modality for human malignancies. Integration of co-stimulatory domains into CARs can augment the activation and function of genetically targeted T cells against tumors. However, the potential for insertional mutagenesis and toxicities due to the infused cells have made development of safe methods for removing transferred cells an important consideration. We have genetically modified human T cells with a lentiviral vector to express a CD20-CAR containing both CD28 and CD137 co-stimulatory domains, a “suicide gene” relying on inducible activation of caspase 9 (iC9), and a truncated CD19 selectable marker. Rapid expansion (2000 fold) of the transduced T cells was achieved in 28 days after stimulation with artificial antigen presenting cells. Transduced T cells exhibited effective CD20-specific cytotoxic activity in vitro and in a mouse xenograft tumor model. Activation of the iC9 suicide switch resulted in efficient removal of transduced T cells both in vitro and in vivo. Our work demonstrates the feasibility and promise of this approach for treating CD20+ malignancies in a safe and more efficient manner. A phase I clinical trial using this approach in patients with relapsed indolent B-NHL is planned. PMID:24358223

Skin Dendritic Cell Targeting via Microneedle Arrays Laden with Antigen-Encapsulated Poly-d,l-lactide-co-Glycolide Nanoparticles Induces Efficient Antitumor and Antiviral Immune Responses

PubMed Central

2013-01-01

The efficacious delivery of antigens to antigen-presenting cells (APCs), in particular, to dendritic cells (DCs), and their subsequent activation remains a significant challenge in the development of effective vaccines. This study highlights the potential of dissolving microneedle (MN) arrays laden with nanoencapsulated antigen to increase vaccine immunogenicity by targeting antigen specifically to contiguous DC networks within the skin. Following in situ uptake, skin-resident DCs were able to deliver antigen-encapsulated poly-d,l-lactide-co-glycolide (PGLA) nanoparticles to cutaneous draining lymph nodes where they subsequently induced significant expansion of antigen-specific T cells. Moreover, we show that antigen-encapsulated nanoparticle vaccination via microneedles generated robust antigen-specific cellular immune responses in mice. This approach provided complete protection in vivo against both the development of antigen-expressing B16 melanoma tumors and a murine model of para-influenza, through the activation of antigen-specific cytotoxic CD8+ T cells that resulted in efficient clearance of tumors and virus, respectively. In addition, we show promising findings that nanoencapsulation facilitates antigen retention into skin layers and provides antigen stability in microneedles. Therefore, the use of biodegradable polymeric nanoparticles for selective targeting of antigen to skin DC subsets through dissolvable MNs provides a promising technology for improved vaccination efficacy, compliance, and coverage. PMID:23373658

Combining a CD20 chimeric antigen receptor and an inducible caspase 9 suicide switch to improve the efficacy and safety of T cell adoptive immunotherapy for lymphoma.

PubMed

Budde, Lihua E; Berger, Carolina; Lin, Yukang; Wang, Jinjuan; Lin, Xubin; Frayo, Shani E; Brouns, Shaunda A; Spencer, David M; Till, Brian G; Jensen, Michael C; Riddell, Stanley R; Press, Oliver W

2013-01-01

Modification of T cells with chimeric antigen receptors (CAR) has emerged as a promising treatment modality for human malignancies. Integration of co-stimulatory domains into CARs can augment the activation and function of genetically targeted T cells against tumors. However, the potential for insertional mutagenesis and toxicities due to the infused cells have made development of safe methods for removing transferred cells an important consideration. We have genetically modified human T cells with a lentiviral vector to express a CD20-CAR containing both CD28 and CD137 co-stimulatory domains, a "suicide gene" relying on inducible activation of caspase 9 (iC9), and a truncated CD19 selectable marker. Rapid expansion (2000 fold) of the transduced T cells was achieved in 28 days after stimulation with artificial antigen presenting cells. Transduced T cells exhibited effective CD20-specific cytotoxic activity in vitro and in a mouse xenograft tumor model. Activation of the iC9 suicide switch resulted in efficient removal of transduced T cells both in vitro and in vivo. Our work demonstrates the feasibility and promise of this approach for treating CD20(+) malignancies in a safe and more efficient manner. A phase I clinical trial using this approach in patients with relapsed indolent B-NHL is planned.

A theranostic nanoplatform: magneto-gold@fluorescence polymer nanoparticles for tumor targeting T1&T2-MRI/CT/NIR fluorescence imaging and induction of genuine autophagy mediated chemotherapy.

PubMed

Wang, Guannan; Qian, Kun; Mei, Xifan

2018-06-14

Multifunctional nanoparticles, bearing low toxicity and tumor-targeting properties, coupled with multifunctional diagnostic imaging and enhanced treatment efficacy, have drawn tremendous attention due to their enormous potential for medical applications. Herein, we report a new kind of biocompatible and tumor-targeting magneto-gold@fluorescent polymer nanoparticle (MGFs-LyP-1), which is based on ultra-small magneto-gold (Fe 3 O 4 -Au) nanoparticles and NIR emissive fluorescent polymers by a solvent-mediated method. This kind of nanoparticle could be taken up efficiently and simultaneously serve for in vivo tumor targeting T 1 &T 2 -MRI/CT/near infrared (NIR) fluorescence bioimaging. Furthermore, the nanoparticles exhibit small size, higher tumor targeting accumulation, excellent cytocompatibility for long-term tracking, and no disturbing cell proliferation and differentiation. Moreover, clear and convincing evidence proves that as-synthesized MGFs-LyP-1 could elicit genuine autophagy via inducing autophagosome formation, which offers a definite synergistic effect to enhance cancer therapy with doxorubicin (DOX) at a nontoxic concentration through enhancement of the autophagy flux. Meanwhile, the as-prepared nanoparticles could be rapidly cleared from mice without any obvious organ impairment. The results indeed reveal a promising prospect of an MGFs-LyP-1 contrast agent with low toxicity and high efficiency for promising application in biomedicine.

The production of cyanobacterial carbon under nitrogen-limited cultivation and its potential for nitrate removal.

PubMed

Huang, Yingying; Li, Panpan; Chen, Guiqin; Peng, Lin; Chen, Xuechu

2018-01-01

Harmful cyanobacterial blooms (CyanoHABs) represent a serious threat to aquatic ecosystems. A beneficial use for these harmful microorganisms would be a promising resolution of this urgent issue. This study applied a simple method, nitrogen limitation, to cultivate cyanobacteria aimed at producing cyanobacterial carbon for denitrification. Under nitrogen-limited conditions, the common cyanobacterium, Microcystis, efficiently used nitrate, and had a higher intracellular C/N ratio. More importantly, organic carbons easily leached from its dry powder; these leachates were biodegradable and contained a larger amount of dissolved organic carbon (DOC) and carbohydrates, but a smaller amount of dissolved total nitrogen (DTN) and proteins. When applied to an anoxic system with a sediment-water interface, a significant increase of the specific NO X - -N removal rate was observed that was 14.2 times greater than that of the control. This study first suggests that nitrogen-limited cultivation is an efficient way to induce organic and carbohydrate accumulation in cyanobacteria, as well as a high C/N ratio, and that these cyanobacteria can act as a promising carbon source for denitrification. The results indicate that application as a carbon source is not only a new way to utilize cyanobacteria, but it also contributes to nitrogen removal in aquatic ecosystems, further limiting the proliferation of CyanoHABs. Copyright © 2017. Published by Elsevier Ltd.

Summary of past experience in natural laminar flow and experimental program for resilient leading edge

NASA Technical Reports Server (NTRS)

Carmichael, B. H.

1979-01-01

The potential of natural laminar flow for significant drag reduction and improved efficiency for aircraft is assessed. Past experience with natural laminar flow as reported in published and unpublished data and personal observations of various researchers is summarized. Aspects discussed include surface contour, waviness, and smoothness requirements; noise and vibration effects on boundary layer transition, boundary layer stability criteria; flight experience with natural laminar flow and suction stabilized boundary layers; and propeller slipstream, rain, frost, ice and insect contamination effects on boundary layer transition. The resilient leading edge appears to be a very promising method to prevent leading edge insect contamination.

Expression of Plasmodium falciparum Circumsporozoite Proteins in Escherichia coli for Potential Use in a Human Malaria Vaccine

NASA Astrophysics Data System (ADS)

Young, James F.; Hockmeyer, Wayne T.; Gross, Mitchell; Ripley Ballou, W.; Wirtz, Robert A.; Trosper, James H.; Beaudoin, Richard L.; Hollingdale, Michael R.; Miller, Louis H.; Diggs, Carter L.; Rosenberg, Martin

1985-05-01

The circumsporozoite (CS) protein of the human malaria parasite Plasmodium falciparum may be the most promising target for the development of a malaria vaccine. In this study, proteins composed of 16, 32, or 48 tandem copies of a tetrapeptide repeating sequence found in the CS protein were efficiently expressed in the bacterium Escherichia coli. When injected into mice, these recombinant products resulted in the production of high titers of antibodies that reacted with the authentic CS protein on live sporozoites and blocked sporozoite invasion of human hepatoma cells in vitro. These CS protein derivatives are therefore candidates for a human malaria vaccine.

Development and test of a 100 kVA superconducting transformer operated at 77 K

NASA Astrophysics Data System (ADS)

Kummeth, P.; Schlosser, R.; Massek, P.; Schmidt, H.; Albrecht, C.; Breitfelder, D.; Neumüller, H.-W.

2000-05-01

High-temperature superconducting (HTS) transformers are very promising candidates for application in electrical power engineering. Their main advantages are reduced size, weight, better efficiency and reduced potential fire and environmental hazards. We have designed, constructed and tested a 100 kVA HTS power transformer operated at 77 K. The nominal primary and secondary currents (voltages) are 18 A (5.6 kV) and 92 A (1.1 kV), respectively. No-load tests, short-circuit tests and load tests proved repeatedly that the transformer has the rated capacity. HTS winding losses of 20.6 W and iron losses of 403 W were measured.

Traditional and emerging materials for optical metasurfaces

NASA Astrophysics Data System (ADS)

Zhu, Alexander Y.; Kuznetsov, Arseniy I.; Luk'yanchuk, Boris; Engheta, Nader; Genevet, Patrice

2017-03-01

One of the most promising and vibrant research areas in nanotechnology has been the field of metasurfaces. These are two dimensional representations of metaatoms, or artificial interfaces designed to possess specialized electromagnetic properties which do not occur in nature, for specific applications. In this article, we present a brief review of metasurfaces from a materials perspective, and examine how the choice of different materials impact functionalities ranging from operating bandwidth to efficiencies. We place particular emphasis on emerging and non-traditional materials for metasurfaces such as high index dielectrics, topological insulators and digital metamaterials, and the potentially transformative role they could play in shaping further advances in the field.

Confocal microscopy to guide laser ablation of basal cell carinoma: a preliminary feasibility study

NASA Astrophysics Data System (ADS)

Larson, Bjorg A.; Sierra, Heidy; Chen, Jason; Rajadhyaksha, Milind

2013-03-01

Laser ablation may be a promising method for removal of skin lesions, with the potential for better cosmetic outcomes and reduced scarring and infection. An obstacle to implementing laser ablation is that the treatment leaves no tissue for histopathological analysis. Pre-operative and intra-operative mapping of BCCs using confocal microscopy may guide the ablation of the tumor until all tumor is removed. We demonstrate preliminary feasibility of confocal microscopy to guide laser ablation of BCCs in freshly excised tissue from Mohs surgery. A 2940 nm Er:YAG laser provides efficient ablation of tumor with reduced thermal damage to the surrounding tissue.

Monitoring Urban Heat Island Through Google Earth Engine: Potentialities and Difficulties in Different Cities of the United States

NASA Astrophysics Data System (ADS)

Ravanelli, R.; Nascetti, A.; Cirigliano, R. V.; Di Rico, C.; Monti, P.; Crespi, M.

2018-04-01

The aim of this work is to exploit the large-scale analysis capabilities of the innovative Google Earth Engine platform in order to investigate the temporal variations of the Urban Heat Island phenomenon as a whole. A intuitive methodology implementing a largescale correlation analysis between the Land Surface Temperature and Land Cover alterations was thus developed.The results obtained for the Phoenix MA are promising and show how the urbanization heavily affects the magnitude of the UHI effects with significant increases in LST. The proposed methodology is therefore able to efficiently monitor the UHI phenomenon.

Bifunctional alkaline oxygen electrodes

NASA Technical Reports Server (NTRS)

Swette, L.; Kackley, N.; Mccatty, S. A.

1991-01-01

The authors describe the identification and testing of electrocatalysts and supports for the positive electrode of moderate-temperature, single-unit, rechargeable alkaline fuel cells. Recent work on Na(x)Pt3O4, a potential bifunctional catalyst, is described, as well as the application of novel approaches to the development of more efficient bifunctional electrode structures. The three dual-character electrodes considered here showed similar superior performance; the Pt/RhO2 and Rh/RhO2 electrodes showed slightly better performance than the Pt/IrO2 electrode. It is concluded that Na(x)Pt3O4 continues to be a promising bifunctional oxygen electrode catalyst but requires further investigation and development.

High Efficiency Water Heating Technology Development Final Report, Part II: CO 2 and Absorption-Based Residential Heat Pump Water Heater Development

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

Gluesenkamp, Kyle R.; Abdelaziz, Omar; Patel, Viral K.

2017-05-01

The two objectives of this project were to 1.demonstrate an affordable path to an ENERGY STAR qualified electric heat pump water heater (HPWH) based on low-global warming potential (GWP) CO 2 refrigerant, and 2.demonstrate an affordable path to a gas-fired absorption-based heat pump water heater with a gas energy factor (EF) greater than 1.0. The first objective has been met, and the project has identified a promising low-cost option capable of meeting the second objective. This report documents the process followed and results obtained in addressing these objectives.

Assessing the potential of polyculture to accelerate algal biofuel production

DOE PAGES

Newby, Deborah T.; Mathews, Teresa J.; Pate, Ron C.; ...

2016-10-24

To date, the algal biofuel industry has focused on the cultivation of monocultures of highly productive algal strains, but scaling up production remains challenging. However, algal monocultures are difficult to maintain because they are easily contaminated by wild algal strains, grazers, and pathogens. In contrast, theory suggests that polycultures (multispecies assemblages) can promote both ecosystem stability and productivity. A greater understanding of species interactions and how communities change with time will need to be developed before polycultures can be successfully applied to large-scale algal production efforts. Here in this paper we review the agricultural and ecological literature to explore opportunitiesmore » for increased annual biomass production through the use of algal polycultures. We discuss case studies where algal polycultures have been successfully maintained for industries other than the biofuel industry, as well as the few studies that have compared biomass production of algal polycultures to that of monocultures. Assemblages that include species with complementary traits are of particular promise. These assemblages have the potential not only to increase crop productivity and stability, but they may also be capable of utilizing natural resources (e.g. light, nutrients, water) more efficiently via tighter niche packing. Therefore, algal polycultures show promise for enhancing biomass productivity, enabling sustainable production and reducing overall production costs.« less

Importance of Electrode Material in the Electrochemical Treatment of Wastewater Containing Organic Pollutants

NASA Astrophysics Data System (ADS)

Panizza, Marco

Electrochemical oxidation is a promising method for the treatment of wastewaters containing organic compounds. As a general rule, the electrochemical incineration of organics at a given electrode can take place at satisfactory rates and without electrode deactivation only at high anodic potentials in the region of the water discharge due to the participation of the intermediates of oxygen evolution. The nature of the electrode material strongly influences both the selectivity and the efficiency of the process. In particular, anodes with low oxygen evolution overpotential (i.e., good catalysts for oxygen evolution reactions), such as graphite, IrO2, RuO2, and Pt only permit the partial oxidation of organics, while anodes with high oxygen evolution overpotential (i.e., anodes that are poor catalysts for oxygen evolution reactions), such as SnO2, PbO2, and boron-doped diamond (BDD) favor the complete oxidation of organics to CO2 and so are ideal electrodes for wastewater treatment.However, the application of SnO2 and PbO2 anodes may be limited by their short service life and the risk of lead contamination, while BDD electrodes exhibit good chemical and electrochemical stability, a long life, and a wide potential window for water discharge, and are thus promising anodes for industrial-scale wastewater treatment.

Functional polycarbonates and their self-assemblies as promising non-viral vectors.

PubMed

Seow, Wei Yang; Yang, Yi Yan

2009-10-01

Polycarbonates are promising biomaterials due to their biocompatibility, degradability and low toxicity. In this study, a series of COOH-functionalized polycarbonates was synthesized via an organocatalytic ring opening polymerization pathway under mild conditions. The polymers displayed a range of molecular weights (M(w): 3.1, 5.5 and 9.7 kDa) and were very narrowly distributed (polydispersity index: 1.07, 1.07 and 1.15 respectively). Aliphatic amines with different chain lengths (triethylenetetramine, tetraethylenepentamine or pentaethylenehexamine) were then conjugated onto the polycarbonate backbone using DIC/NHS chemistry. These amine-functionalized polycarbonates could form nanoparticles upon simple dissolution in water and had CMC values ranging from 22 to 45 mg/L. It was found that a longer amine chain resulted in greater buffering capacity, more positive zeta potential and smaller hydrodynamic size of the polymeric nanoparticles. Results from gel retardation assays indicated that the polymers were able to condense DNA. In-vitro studies further demonstrated that selected amine-functionalized polycarbonates could mediate efficient luciferase expression in HEK293, HepG2 and 4T1 cell lines at levels that were comparable, or even superior, to the polyethylenimine (PEI) standard. Importantly, minimal cytotoxicty was induced in the cells. These functional polycarbonates therefore have the potential to be a useful non-viral vector for gene therapy.

Bacteriophages and medical oncology: targeted gene therapy of cancer.

PubMed

Bakhshinejad, Babak; Karimi, Marzieh; Sadeghizadeh, Majid

2014-08-01

Targeted gene therapy of cancer is of paramount importance in medical oncology. Bacteriophages, viruses that specifically infect bacterial cells, offer a variety of potential applications in biomedicine. Their genetic flexibility to go under a variety of surface modifications serves as a basis for phage display methodology. These surface manipulations allow bacteriophages to be exploited for targeted delivery of therapeutic genes. Moreover, the excellent safety profile of these viruses paves the way for their potential use as cancer gene therapy platforms. The merge of phage display and combinatorial technology has led to the emergence of phage libraries turning phage display into a high throughput technology. Random peptide libraries, as one of the most frequently used phage libraries, provide a rich source of clinically useful peptide ligands. Peptides are known as a promising category of pharmaceutical agents in medical oncology that present advantages such as inexpensive synthesis, efficient tissue penetration and the lack of immunogenicity. Phage peptide libraries can be screened, through biopanning, against various targets including cancer cells and tissues that results in obtaining cancer-homing ligands. Cancer-specific peptides isolated from phage libraries show huge promise to be utilized for targeting of various gene therapy vectors towards malignant cells. Beyond doubt, bacteriophages will play a more impressive role in the future of medical oncology.

The Potential of Knowing More: A Review of Data-Driven Urban Water Management.

PubMed

Eggimann, Sven; Mutzner, Lena; Wani, Omar; Schneider, Mariane Yvonne; Spuhler, Dorothee; Moy de Vitry, Matthew; Beutler, Philipp; Maurer, Max

2017-03-07

The promise of collecting and utilizing large amounts of data has never been greater in the history of urban water management (UWM). This paper reviews several data-driven approaches which play a key role in bringing forward a sea change. It critically investigates whether data-driven UWM offers a promising foundation for addressing current challenges and supporting fundamental changes in UWM. We discuss the examples of better rain-data management, urban pluvial flood-risk management and forecasting, drinking water and sewer network operation and management, integrated design and management, increasing water productivity, wastewater-based epidemiology and on-site water and wastewater treatment. The accumulated evidence from literature points toward a future UWM that offers significant potential benefits thanks to increased collection and utilization of data. The findings show that data-driven UWM allows us to develop and apply novel methods, to optimize the efficiency of the current network-based approach, and to extend functionality of today's systems. However, generic challenges related to data-driven approaches (e.g., data processing, data availability, data quality, data costs) and the specific challenges of data-driven UWM need to be addressed, namely data access and ownership, current engineering practices and the difficulty of assessing the cost benefits of data-driven UWM.

Bandgap engineering and charge separation in two-dimensional GaS-based van der Waals heterostructures for photocatalytic water splitting

NASA Astrophysics Data System (ADS)

Wang, Biao; Kuang, Anlong; Luo, Xukai; Wang, Guangzhao; Yuan, Hongkuan; Chen, Hong

2018-05-01

Two-dimensional (2D) gallium sulfide (GaS), hexagonal boron nitride (h-BN) and graphitic carbon nitride (g-C3N4) have been fabricated and expected to be promising photocatalysts under ultraviolet irradiation. Here, we employ hybrid density functional calculations to explore the potential of the 2D GaS-based heterojunctions GaS/h-BN (g-C3N4) for the design of efficient water redox photocatalysts. Both heterostructures can be formed via van der Waals (vdW) interaction and are direct bandgap semiconductors, whose bandgaps are reduced comparing with isolated GaS, h-BN or g-C3N4 monolayers and whose bandedges straddle water redox potentials. Furthermore, the optical absorption of GaS/h-BN (g-C3N4) heterostructures is observably enhanced in the ultraviolet-visible (UV-vis) light range. The electron-hole pairs in GaS/h-BN (g-C3N4) heterostructures are completely separated from different layers. In addition, the in-plane biaxial strain can effectively modulate the electronic properties of GaS/h-BN (g-C3N4) heterostructures. Thus the GaS/h-BN (g-C3N4) heterostructures are anticipated to be promising candidates for photocatalytic water splitting to produce hydrogen.

Suppression of Murine Colitis and its Associated Cancer by Carcinoembryonic Antigen-Specific Regulatory T Cells

PubMed Central

Blat, Dan; Zigmond, Ehud; Alteber, Zoya; Waks, Tova; Eshhar, Zelig

2014-01-01

The adoptive transfer of regulatory T cells (Tregs) offers a promising strategy to combat pathologies that are characterized by aberrant immune activation, including graft rejection and autoinflammatory diseases. Expression of a chimeric antigen receptor (CAR) gene in Tregs redirects them to the site of autoimmune activity, thereby increasing their suppressive efficiency while avoiding systemic immunosuppression. Since carcinoembryonic antigen (CEA) has been shown to be overexpressed in both human colitis and colorectal cancer, we treated CEA-transgenic mice that were induced to develop colitis with CEA-specific CAR Tregs. Two disease models were employed: T-cell-transfer colitis as well as the azoxymethane–dextran sodium sulfate model for colitis-associated colorectal cancer. Systemically administered CEA-specific (but not control) CAR Tregs accumulated in the colons of diseased mice. In both model systems, CEA-specific CAR Tregs suppressed the severity of colitis compared to control Tregs. Moreover, in the azoxymethane–dextran sodium sulfate model, CEA-specific CAR Tregs significantly decreased the subsequent colorectal tumor burden. Our data demonstrate that CEA-specific CAR Tregs exhibit a promising potential in ameliorating ulcerative colitis and in hindering colorectal cancer development. Collectively, this study provides a proof of concept for the therapeutic potential of CAR Tregs in colitis patients as well as in other autoimmune inflammatory disorders. PMID:24686242

Assessing the potential of polyculture to accelerate algal biofuel production

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

Newby, Deborah T.; Mathews, Teresa J.; Pate, Ron C.

To date, the algal biofuel industry has focused on the cultivation of monocultures of highly productive algal strains, but scaling up production remains challenging. However, algal monocultures are difficult to maintain because they are easily contaminated by wild algal strains, grazers, and pathogens. In contrast, theory suggests that polycultures (multispecies assemblages) can promote both ecosystem stability and productivity. A greater understanding of species interactions and how communities change with time will need to be developed before polycultures can be successfully applied to large-scale algal production efforts. Here in this paper we review the agricultural and ecological literature to explore opportunitiesmore » for increased annual biomass production through the use of algal polycultures. We discuss case studies where algal polycultures have been successfully maintained for industries other than the biofuel industry, as well as the few studies that have compared biomass production of algal polycultures to that of monocultures. Assemblages that include species with complementary traits are of particular promise. These assemblages have the potential not only to increase crop productivity and stability, but they may also be capable of utilizing natural resources (e.g. light, nutrients, water) more efficiently via tighter niche packing. Therefore, algal polycultures show promise for enhancing biomass productivity, enabling sustainable production and reducing overall production costs.« less

Down-conversion emission of Ce3+-Tb3+ co-doped CaF2 hollow spheres and application for solar cells

NASA Astrophysics Data System (ADS)

Cheng, Yufei; Wang, Yongbo; Teng, Feng; Dong, Hua; Chen, Lida; Mu, Jianglong; Sun, Qian; Fan, Jun; Hu, Xiaoyun; Miao, Hui

2018-03-01

Luminescent downconversion is a promising way to harvest ultraviolet sunlight and transform it into visible light that can be absorbed by solar cells, and has potential to improve their photoelectric conversion efficiency. In this work, the uniform hollow spheres and well dispersed CaF2 phosphors doped with rare-earth Ce3+ and Tb3+ ions are prepared by a one-step hydrothermal synthesis method. Benefiting from the stronger ability of absorption and emission and excellent transparency property, we demonstrate that the application of the doped nanocrystals can efficiently improve visible light transmittance. The chosen phosphors are added in the SiO2 sols so as to get the anti-reflection coatings with wavelength conversion bi-functional films, promoting the optical transmittance in the visible and near-infrared range which matches with the range of the band gap energy of silicon semiconductor. Optimized photoelectric conversion efficiency of 14.35% and the external quantum efficiency over 70% from 450 to 950 nm are obtained through the silicon solar cells with 0.10 g phosphors coating. Compared with the pure glass devices, the photoelectric conversion efficiency is enhanced by 0.69%. This work indicates that fluorescent downconversion not only can serve as proof of principles for improving photoelectric conversion efficiency of solar cells but also may be helpful to practical application in the future.

Concentrating light in Cu(In,Ga)Se2 solar cells

NASA Astrophysics Data System (ADS)

Schmid, M.; Yin, G.; Song, M.; Duan, S.; Heidmann, B.; Sancho-Martinez, D.; Kämmer, S.; Köhler, T.; Manley, P.; Lux-Steiner, M. Ch.

2016-09-01

Light concentration has proven beneficial for solar cells, most notably for highly efficient but expensive absorber materials using high concentrations and large scale optics. Here we investigate light concentration for cost efficient thinfilm solar cells which show nano- or microtextured absorbers. Our absorber material of choice is Cu(In,Ga)Se2 (CIGSe) which has a proven stabilized record efficiency of 22.6% and which - despite being a polycrystalline thin-film material - is very tolerant to environmental influences. Taking a nanoscale approach, we concentrate light in the CIGSe absorber layer by integrating photonic nanostructures made from dielectric materials. The dielectric nanostructures give rise to resonant modes and field localization in their vicinity. Thus when inserted inside or adjacent to the absorber layer, absorption and efficiency enhancement are observed. In contrast to this internal absorption enhancement, external enhancement is exploited in the microscale approach: mm-sized lenses can be used to concentrate light onto CIGSe solar cells with lateral dimensions reduced down to the micrometer range. These micro solar cells come with the benefit of improved heat dissipation compared to the large scale concentrators and promise compact high efficiency devices. Both approaches of light concentration allow for reduction in material consumption by restricting the absorber dimension either vertically (ultra-thin absorbers for dielectric nanostructures) or horizontally (micro absorbers for concentrating lenses) and have significant potential for efficiency enhancement.

Concentrating light in Cu(In,Ga)Se2 solar cells

NASA Astrophysics Data System (ADS)

Schmid, Martina; Yin, Guanchao; Song, Min; Duan, Shengkai; Heidmann, Berit; Sancho-Martinez, Diego; Kämmer, Steven; Köhler, Tristan; Manley, Phillip; Lux-Steiner, Martha Ch.

2017-01-01

Light concentration has proven beneficial for solar cells, most notably for highly efficient but expensive absorber materials using high concentrations and large scale optics. Here, we investigate the light concentration for cost-efficient thin-film solar cells that show nano- or microtextured absorbers. Our absorber material of choice is Cu(In,Ga)Se2 (CIGSe), which has a proven stabilized record efficiency of 22.6% and which-despite being a polycrystalline thin-film material-is very tolerant to environmental influences. Taking a nanoscale approach, we concentrate light in the CIGSe absorber layer by integrating photonic nanostructures made from dielectric materials. The dielectric nanostructures give rise to resonant modes and field localization in their vicinity. Thus, when inserted inside or adjacent to the absorber layer, absorption and efficiency enhancement are observed. In contrast to this internal absorption enhancement, external enhancement is exploited in the microscaled approach: mm-sized lenses can be used to concentrate light onto CIGSe solar cells with lateral dimensions reduced down to the micrometer range. These micro solar cells come with the benefit of improved heat dissipation compared with the large scale concentrators and promise compact high-efficiency devices. Both approaches of light concentration allow for reduction in material consumption by restricting the absorber dimension either vertically (ultrathin absorbers for dielectric nanostructures) or horizontally (microabsorbers for concentrating lenses) and have significant potential for efficiency enhancement.

Efficiency of energy recovery from municipal solid waste and the resultant effect on the greenhouse gas balance.

PubMed

Gohlke, Oliver

2009-11-01

Global warming is a focus of political interest and life-cycle assessment of waste management systems reveals that energy recovery from municipal solid waste is a key issue. This paper demonstrates how the greenhouse gas effects of waste treatment processes can be described in a simplified manner by considering energy efficiency indicators. For evaluation to be consistent, it is necessary to use reasonable system boundaries and to take the generation of electricity and the use of heat into account. The new European R1 efficiency criterion will lead to the development and implementation of optimized processes/systems with increased energy efficiency which, in turn, will exert an influence on the greenhouse gas effects of waste management in Europe. Promising technologies are: the increase of steam parameters, reduction of in-plant energy consumption, and the combined use of heat and power. Plants in Brescia and Amsterdam are current examples of good performance with highly efficient electricity generation. Other examples of particularly high heat recovery rates are the energy-from-waste (EfW) plants in Malmö and Gothenburg. To achieve the full potential of greenhouse gas reduction in waste management, it is necessary to avoid landfilling combustible wastes, for example, by means of landfill taxes and by putting incentives in place for increasing the efficiency of EfW systems.

Non-viral vectors based on magnetoplexes, lipoplexes and polyplexes for VEGF gene delivery into central nervous system cells.

PubMed

Villate-Beitia, Ilia; Puras, Gustavo; Soto-Sánchez, Cristina; Agirre, Mireia; Ojeda, Edilberto; Zarate, Jon; Fernández, Eduardo; Pedraz, José Luis

2017-04-15

Nanotechnology based non-viral vectors hold great promise to deliver therapeutic genes into the central nervous system (CNS) in a safe and controlled way. Vascular endothelial growth factor (VEGF) is a potential therapeutic gene candidate for CNS disorders due to its specific roles in brain angiogenesis and neuroprotection. In this work, we elaborated three different non-viral vectors based on magnetic, cationic lipid and polymeric nanoparticles complexed to the phVEGF165aIRESGFP plasmid, which codifies the VEGF protein -extracellular- and the green fluorescent protein (GFP) -intracellular-. Nanoparticles and corresponding nanoplexes -magnetoplexes, lipoplexes and polyplexes- were characterized in terms of size, zeta potential, polydispersity index, morphology and ability to bind, release and protect DNA. Transfection efficiencies of nanoplexes were measured in terms of percentage of GFP expressing cells, mean fluorescent intensity (MFI) and VEGF (ng/ml) production in HEK293, C6 and primary neuronal culture cells. Magnetoplexes showed the highest transfection efficiencies in C6, followed by lipoplexes, and in primary neuronal culture cells, followed by polyplexes. Lipoplexes were the most efficient in HEK293 cells, followed by magnetoplexes. The biological activity of VEGF was confirmed by its proliferative effect in HUVEC cells. Overall, these results provide new insights for VEGF gene delivery into CNS cells using non-viral vectors. Copyright © 2017. Published by Elsevier B.V.

Internalized compartments encapsulated nanogels for targeted drug delivery

NASA Astrophysics Data System (ADS)

Yu, Jicheng; Zhang, Yuqi; Sun, Wujin; Wang, Chao; Ranson, Davis; Ye, Yanqi; Weng, Yuyan; Gu, Zhen

2016-04-01

Drug delivery systems inspired by natural particulates hold great promise for targeted cancer therapy. An endosome formed by internalization of plasma membrane has a massive amount of membrane proteins and receptors on the surface, which is able to specifically target the homotypic cells. Herein, we describe a simple method to fabricate an internalized compartments encapsulated nanogel with endosome membrane components (EM-NG) from source cancer cells. Following intracellular uptake of methacrylated hyaluronic acid (m-HA) adsorbed SiO2/Fe3O4 nanoparticles encapsulating a crosslinker and a photoinitiator, EM-NG was readily prepared through in situ crosslinking initiated under UV irradiation after internalization. The resulting nanogels loaded with doxorubicin (DOX) displayed enhanced internalization efficiency to the source cells through a specific homotypic affinity in vitro. However, when treated with the non-source cells, the EM-NGs exhibited insignificant difference in therapeutic efficiency compared to a bare HA nanogel with DOX. This study illustrates the potential of utilizing an internalized compartments encapsulated formulation for targeted cancer therapy, and offers guidelines for developing a natural particulate-inspired drug delivery system.Drug delivery systems inspired by natural particulates hold great promise for targeted cancer therapy. An endosome formed by internalization of plasma membrane has a massive amount of membrane proteins and receptors on the surface, which is able to specifically target the homotypic cells. Herein, we describe a simple method to fabricate an internalized compartments encapsulated nanogel with endosome membrane components (EM-NG) from source cancer cells. Following intracellular uptake of methacrylated hyaluronic acid (m-HA) adsorbed SiO2/Fe3O4 nanoparticles encapsulating a crosslinker and a photoinitiator, EM-NG was readily prepared through in situ crosslinking initiated under UV irradiation after internalization. The resulting nanogels loaded with doxorubicin (DOX) displayed enhanced internalization efficiency to the source cells through a specific homotypic affinity in vitro. However, when treated with the non-source cells, the EM-NGs exhibited insignificant difference in therapeutic efficiency compared to a bare HA nanogel with DOX. This study illustrates the potential of utilizing an internalized compartments encapsulated formulation for targeted cancer therapy, and offers guidelines for developing a natural particulate-inspired drug delivery system. Electronic supplementary information (ESI) available: Synthesis of m-HA; synthesis of rhodamine-HA derivative; supplementary data on relative fluorescence intensity of DOX-EN-NGs on HeLa cells. See DOI: 10.1039/c5nr08895j

Core-Crosslinked Polymeric Micelles: Principles, Preparation, Biomedical Applications and Clinical Translation

PubMed Central

Rijcken, Cristianne J.; Kiessling, Fabian; Hennink, Wim E.; Lammers, Twan

2015-01-01

Polymeric micelles (PM) are extensively used to improve the delivery of hydrophobic drugs. Many different PM have been designed and evaluated over the years, and some of them have steadily progressed through clinical trials. Increasing evidence suggests, however, that for prolonged circulation times and for efficient EPR-mediated drug targeting to tumors and to sites of inflammation, PM need to be stabilized, to prevent premature disintegration. Core-crosslinking is among the most popular methods to improve the in vivo stability of PM, and a number of core-crosslinked polymeric micelles (CCPM) have demonstrated promising efficacy in animal models. The latter is particularly true for CCPM in which (pro−) drugs are covalently entrapped. This ensures proper drug retention in the micelles during systemic circulation, efficient drug delivery to pathological sites via EPR, and tailorable drug release kinetics at the target site. We here summarize recent advances in the CCPM field, addressing the chemistry involved in preparing them, their in vitro and in vivo performance, potential biomedical applications, and guidelines for efficient clinical translation. PMID:25893004

Hybrid WDM/OCDMA for next generation access network

NASA Astrophysics Data System (ADS)

Wang, Xu; Wada, Naoya; Miyazaki, T.; Cincotti, G.; Kitayama, Ken-ichi

2007-11-01

Hybrid wavelength division multiplexing/optical code division multiple access (WDM/OCDMA) passive optical network (PON), where asynchronous OCDMA traffic transmits over WDM network, can be one potential candidate for gigabit-symmetric fiber-to-the-home (FTTH) services. In a cost-effective WDM/OCDMA network, a large scale multi-port encoder/decoder can be employed in the central office, and a low cost encoder/decoder will be used in optical network unit (ONU). The WDM/OCDMA system could be one promising solution to the symmetric high capacity access network with high spectral efficiency, cost effective, good flexibility and enhanced security. Asynchronous WDM/OCDMA systems have been experimentally demonstrated using superstructured fiber Bragg gratings (SSFBG) and muti-port OCDMA en/decoders. The total throughput has reached above Tera-bit/s with spectral efficiency of about 0.41. The key enabling techniques include ultra-long SSFBG, multi-port E/D with high power contrast ratio, optical thresholding, differential phase shift keying modulation with balanced detection, forward error correction, and etc. Using multi-level modulation formats to carry multi-bit information with single pulse, the total capacity and spectral efficiency could be further enhanced.

Erythrocyte membrane based cationic polymer-mcDNA complexes as an efficient gene delivery system.

PubMed

Huang, Ping; Zhao, Jing; Wei, Chiju; Hou, Xiaohu; Chen, Pingzhang; Tan, Yan; He, Cheng-Yi; Wang, Zhiyong; Chen, Zhi-Ying

2016-12-20

Gene therapy has great promise for the treatment of obtained and inherited serious diseases. However, the lack of safe and efficient gene delivery systems remains a barrier for their clinical application. Here, we reported a potential gene delivery vehicle composed of the erythrocyte membrane and cationic polymers, for example the XtremeGENE from Roche and the ε-caprolactone modified polyethylenimine. In addition to high efficiency, this system showed negligible cytotoxicity compared to the two cationic polymers alone in various cell lines, including human embryonic kidney cells (293T), human liver cancer cells (Huh7 and HepG2), murine dendritic cells (DC2.4) and human umbilical cord mesenchymal stem cells (Hu-MSCs). Moreover, the results of confocal laser scanning microscopy and flow cytometry suggested that the cell uptake of this gene vector was improved and might be introduced by the fusion interaction between the erythrocyte membrane and targeted cells.Thus, all the results revealed that the erythrocyte membrane based gene delivery system might be able to serve as an excellent gene delivery system.

Building a Six-Junction Inverted Metamorphic Concentrator Solar Cell

DOE PAGES

Geisz, John F.; Steiner, Myles A.; Jain, Nikhil; ...

2017-12-20

We propose practical six-junction (6J) inverted metamorphic multijunction (IMM) concentrator solar cell designs with the potential to exceed 50% efficiency using moderately high quality junction materials. We demonstrate the top three junctions and their monolithic integration lattice matched to GaAs using 2.1-eV AlGaInP, 1.7-eV AlGaAs or GaInAsP, and 1.4-eV GaAs with external radiative efficiencies >0.1%. We demonstrate tunnel junctions with peak tunneling current >400 A/cm 2 that are transparent to <2.1-eV light. We compare the bottom three GaInAs(p) junctions with bandgaps of 1.2, 1.0, and 0.7 eV grown on InP and transparent metamorphic grades with low dislocation densities. The solutionmore » to an integration challenge resulting from Zn diffusion in the GaAs junction is illustrated in a five-junction IMM. Excellent 1-sun performance is demonstrated in a complete 6J IMM device with VOC = 5.15 V, and a promising pathway toward >50% efficiency at high concentrations is presented.« less

Exclusive Ni-N4 Sites Realize Near-Unity CO Selectivity for Electrochemical CO2 Reduction.

PubMed

Li, Xiaogang; Bi, Wentuan; Chen, Minglong; Sun, Yuexiang; Ju, Huanxin; Yan, Wensheng; Zhu, Junfa; Wu, Xiaojun; Chu, Wangsheng; Wu, Changzheng; Xie, Yi

2017-10-25

Electrochemical reduction of carbon dioxide (CO 2 ) to value-added carbon products is a promising approach to reduce CO 2 levels and mitigate the energy crisis. However, poor product selectivity is still a major obstacle to the development of CO 2 reduction. Here we demonstrate exclusive Ni-N 4 sites through a topo-chemical transformation strategy, bringing unprecedentedly high activity and selectivity for CO 2 reduction. Topo-chemical transformation by carbon layer coating successfully ensures preservation of the Ni-N 4 structure to a maximum extent and avoids the agglomeration of Ni atoms to particles, providing abundant active sites for the catalytic reaction. The Ni-N 4 structure exhibits excellent activity for electrochemical reduction of CO 2 with particularly high selectivity, achieving high faradaic efficiency over 90% for CO in the potential range from -0.5 to -0.9 V and gives a maximum faradaic efficiency of 99% at -0.81 V with a current density of 28.6 mA cm -2 . We anticipate exclusive catalytic sites will shed new light on the design of high-efficiency electrocatalysts for CO 2 reduction.

Building a Six-Junction Inverted Metamorphic Concentrator Solar Cell

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

Geisz, John F.; Steiner, Myles A.; Jain, Nikhil

We propose practical six-junction (6J) inverted metamorphic multijunction (IMM) concentrator solar cell designs with the potential to exceed 50% efficiency using moderately high quality junction materials. We demonstrate the top three junctions and their monolithic integration lattice matched to GaAs using 2.1-eV AlGaInP, 1.7-eV AlGaAs or GaInAsP, and 1.4-eV GaAs with external radiative efficiencies >0.1%. We demonstrate tunnel junctions with peak tunneling current >400 A/cm 2 that are transparent to <2.1-eV light. We compare the bottom three GaInAs(p) junctions with bandgaps of 1.2, 1.0, and 0.7 eV grown on InP and transparent metamorphic grades with low dislocation densities. The solutionmore » to an integration challenge resulting from Zn diffusion in the GaAs junction is illustrated in a five-junction IMM. Excellent 1-sun performance is demonstrated in a complete 6J IMM device with VOC = 5.15 V, and a promising pathway toward >50% efficiency at high concentrations is presented.« less

Two-step photon up-conversion solar cells

PubMed Central

Asahi, Shigeo; Teranishi, Haruyuki; Kusaki, Kazuki; Kaizu, Toshiyuki; Kita, Takashi

2017-01-01

Reducing the transmission loss for below-gap photons is a straightforward way to break the limit of the energy-conversion efficiency of solar cells (SCs). The up-conversion of below-gap photons is very promising for generating additional photocurrent. Here we propose a two-step photon up-conversion SC with a hetero-interface comprising different bandgaps of Al0.3Ga0.7As and GaAs. The below-gap photons for Al0.3Ga0.7As excite GaAs and generate electrons at the hetero-interface. The accumulated electrons at the hetero-interface are pumped upwards into the Al0.3Ga0.7As barrier by below-gap photons for GaAs. Efficient two-step photon up-conversion is achieved by introducing InAs quantum dots at the hetero-interface. We observe not only a dramatic increase in the additional photocurrent, which exceeds the reported values by approximately two orders of magnitude, but also an increase in the photovoltage. These results suggest that the two-step photon up-conversion SC has a high potential for implementation in the next-generation high-efficiency SCs. PMID:28382945

Potential energy surfaces of Polonium isotopes

NASA Astrophysics Data System (ADS)

Nerlo-Pomorska, B.; Pomorski, K.; Schmitt, C.; Bartel, J.

2015-11-01

The evolution of the potential energy landscape is analysed in detail for ten even-even polonium isotopes in the mass range 188\\lt A\\lt 220 as obtained within the macroscopic-microscopic approach, relying on the Lublin-Strasbourg drop model and the Yukawa-folded single-particle energies for calculating the microscopic shell and pairing corrections. A variant of the modified Funny-Hills nuclear shape parametrization is used to efficiently map possible fission paths. The approach explains the main features of the fragment partition as measured in low-energy fission along the polonium chain. The latter lies in a transitional region of the nuclear chart, and will be essential to consistently understand the evolution of fission properties from neutron-deficient mercury to heavy actinides. The ability of our method to predict fission observables over such an extended region looks promising.

Availability and assessment of fixing additives for the in situ remediation of heavy metal contaminated soils: a review.

PubMed

Guo, Guanlin; Zhou, Qixing; Ma, Lene Q

2006-05-01

The use of low-cost and environmental safety amendments for the in situ immobilization of heavy metals has been investigated as a promising method for contaminated soil remediation. Natural materials and waste products from certain industries with high captive capacity of heavy metals can be obtained and employed. Reduction of extractable metal concentration and phytotoxicity could be evaluated and demonstrated by the feasibility of various amendments in fixing remediation. In this review, an extensive list of references has been compiled to provide a summary of information on a wide range of potentially amendment resources, including organic, inorganic and combined organic-inorganic materials. The assessment based on the economic efficiency and environmental risks brought forth the potential application values and future development directions of this method on solving the soil contamination.

Text and Mobile Media Smoking Cessation Service for Young Adults in South Texas: Operation and Cost-Effectiveness Estimation.

PubMed

Ramirez, Amelie G; Chalela, Patricia; Akopian, David; Munoz, Edgar; Gallion, Kipling J; Despres, Cliff; Morales, Jafet; Escobar, Rodrigo; McAlister, Alfred L

2017-07-01

To realize the promising potential of services delivered via smart phones to help young adults quit smoking at a high level of cost-efficiency, we constructed a texting and mobile media system that was promoted in South Texas via social media advertising and other recruitment channels. During the 6-month service period described here, enrollments were achieved for 798 participants with a mean age of 29.3 years. Seven-month texted follow-up found that 21% (171) of the enrollees reported abstinence at that point. This is consistent with high rates of success found in studies of telephone counseling for young adults and confirms that text and mobile media service specifically designed for young adults provide a feasible and potentially cost-effective approach to promoting cessation.

Bifacial dye-sensitized solar cells: A strategy to enhance overall efficiency based on transparent polyaniline electrode

PubMed Central

Wu, Jihuai; Li, Yan; Tang, Qunwei; Yue, Gentian; Lin, Jianming; Huang, Miaoliang; Meng, Lijian

2014-01-01

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, low-cost, high efficiency, good durability, and easy fabrication. However, enhancing the efficiency of the DSSC still is an important issue. Here we devise a bifacial DSSC based on a transparent polyaniline (PANI) counter electrode (CE). Owing to the sunlight irradiation simultaneously from the front and the rear sides, more dye molecules are excited and more carriers are generated, which results in the enhancement of short-circuit current density and therefore overall conversion efficiency. The photoelectric properties of PANI can be improved by modifying with 4-aminothiophenol (4-ATP). The bifacial DSSC with 4-ATP/PANI CE achieves a light-to-electric energy conversion efficiency of 8.35%, which is increased by ~24.6% compared to the DSSC irradiated from the front only. This new concept along with promising results provides a new approach for enhancing the photovoltaic performances of solar cells. PMID:24504117

Can magneto-plasmonic nanohybrids efficiently combine photothermia with magnetic hyperthermia?

NASA Astrophysics Data System (ADS)

Espinosa, Ana; Bugnet, Mathieu; Radtke, Guillaume; Neveu, Sophie; Botton, Gianluigi A.; Wilhelm, Claire; Abou-Hassan, Ali

2015-11-01

Multifunctional hybrid-design nanomaterials appear to be a promising route to meet the current therapeutics needs required for efficient cancer treatment. Herein, two efficient heat nano-generators were combined into a multifunctional single nanohybrid (a multi-core iron oxide nanoparticle optimized for magnetic hyperthermia, and a gold branched shell with tunable plasmonic properties in the NIR region, for photothermal therapy) which impressively enhanced heat generation, in suspension or in vivo in tumours, opening up exciting new therapeutic perspectives.Multifunctional hybrid-design nanomaterials appear to be a promising route to meet the current therapeutics needs required for efficient cancer treatment. Herein, two efficient heat nano-generators were combined into a multifunctional single nanohybrid (a multi-core iron oxide nanoparticle optimized for magnetic hyperthermia, and a gold branched shell with tunable plasmonic properties in the NIR region, for photothermal therapy) which impressively enhanced heat generation, in suspension or in vivo in tumours, opening up exciting new therapeutic perspectives. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06168g

Stem Cell Therapy: A Promising Therapeutic Method for Intracerebral Hemorrhage.

PubMed

Gao, Liansheng; Xu, Weilin; Li, Tao; Chen, Jingyin; Shao, Anwen; Yan, Feng; Chen, Gao

2018-01-01

Spontaneous intracerebral hemorrhage (ICH) is one type of the most devastating cerebrovascular diseases worldwide, which causes high morbidity and mortality. However, efficient treatment is still lacking. Stem cell therapy has shown good neuroprotective and neurorestorative effect in ICH and is a promising treatment. In this study, our aim was to review the therapeutic effects, strategies, related mechanisms and safety issues of various types of stem cell for ICH treatment. Numerous studies had demonstrated the therapeutic effects of diverse stem cell types in ICH. The potential mechanisms include tissue repair and replacement, neurotrophy, promotion of neurogenesis and angiogenesis, anti-apoptosis, immunoregulation and anti-inflammation and so forth. The microenvironment of the central nervous system (CNS) can also influence the effects of stem cell therapy. The detailed therapeutic strategies for ICH treatment such as cell type, the number of cells, time window, and the routes of medication delivery, varied greatly among different studies and had not been determined. Moreover, the safety issues of stem cell therapy for ICH should not be ignored. Stem cell therapy showed good therapeutic effect in ICH, making it a promising treatment. However, safety should be carefully evaluated, and more clinical trials are required before stem cell therapy can be extensively applied to clinical use.

Stabilized wide bandgap perovskite solar cells by tin substitution

DOE PAGES

Yang, Zhibin; Rajagopal, Adharsh; Jo, Sae Byeok; ...

2016-11-16

Wide bandgap MAPb(I 1-yBr y) 3 perovskites show promising potential for application in tandem solar cells. However, unstable photovoltaic performance caused by phase segregation has been observed under illumination when y is above 0.2. Herein, we successfully demonstrate stabilization of the I/Br phase by partially replacing Pb 2+ with Sn 2+ and verify this stabilization with X-ray diffractometry and transient absorption spectroscopy. The resulting MAPb 0.75Sn 0.25(I 1-yBr y) 3 perovskite solar cells show stable photovoltaic performance under continuous illumination. Among these cells, the one based on MAPb 0.75Sn 0.25(I 0.4Br 0.6) 3 perovskite shows the highest efficiency of 12.59%more » with a bandgap of 1.73 eV, which make it a promising wide bandgap candidate for application in tandem solar cells. The engineering of internal bonding environment by partial Sn substitution is believed to be the main reason for making MAPb 0.75Sn 0.25(I 1-yBr y) 3 perovskite less vulnerable to phase segregation during the photostriction under illumination. Furthermore, this study establishes composition engineering of the metal site as a promising strategy to impart phase stability in hybrid perovskites under illumination.« less

Photothermal ablation cancer therapy using homogeneous CsxWO3 nanorods with broad near-infra-red absorption

NASA Astrophysics Data System (ADS)

Guo, Chongshen; Yin, Shu; Yu, Haijun; Liu, Shaoqin; Dong, Qiang; Goto, Takehiro; Zhang, Zhiwen; Li, Yaping; Sato, Tsugio

2013-06-01

Recently, photothermal ablation therapy (PTA) employing near-infrared radiation (NIR) has been extensively investigated as an emerging modality for cancer management. However, the clinical translation of this promising approach is limited by the lack of PTA agents with broad NIR absorption, low cost and high photothermal conversion efficiency. Herein, we have developed PEGylated homogeneous CsxWO3 nanorods (a mean size ~69.3 nm × 12.8 nm) with broad photo-absorption (780-2500 nm) as a novel NIR absorbent for PTA treatment of human cancer. The prepared CsxWO3 nanocrystals displayed strong near-infrared optical absorption with a high molar extinction coefficient (e.g. 4.8 × 1010 M-1 cm-1 at 980 nm), thus generated significant amounts of heat upon excitation with near-infrared light. The PTA study in two human carcinoma cell lines (i.e. A549 lung cancer cells and HeLa ovarian cancer cells) demonstrated that CsxWO3 nanorods can efficiently cause cell death via hyperthermia induced lysosome destruction, cytoskeleton protein degradation, DNA damage and thereafter cellular necrosis or apoptosis. Our study also confirmed the migration of healthy cells migrated from unirradiated areas to dead cell cycle, which is essential for tissue reconstruction and wound healing after photodestruction of tumor tissue. The prompted results reported in the current study imply the promising potential of CsxWO3 nanorods for application in PTA cancer therapy.Recently, photothermal ablation therapy (PTA) employing near-infrared radiation (NIR) has been extensively investigated as an emerging modality for cancer management. However, the clinical translation of this promising approach is limited by the lack of PTA agents with broad NIR absorption, low cost and high photothermal conversion efficiency. Herein, we have developed PEGylated homogeneous CsxWO3 nanorods (a mean size ~69.3 nm × 12.8 nm) with broad photo-absorption (780-2500 nm) as a novel NIR absorbent for PTA treatment of human cancer. The prepared CsxWO3 nanocrystals displayed strong near-infrared optical absorption with a high molar extinction coefficient (e.g. 4.8 × 1010 M-1 cm-1 at 980 nm), thus generated significant amounts of heat upon excitation with near-infrared light. The PTA study in two human carcinoma cell lines (i.e. A549 lung cancer cells and HeLa ovarian cancer cells) demonstrated that CsxWO3 nanorods can efficiently cause cell death via hyperthermia induced lysosome destruction, cytoskeleton protein degradation, DNA damage and thereafter cellular necrosis or apoptosis. Our study also confirmed the migration of healthy cells migrated from unirradiated areas to dead cell cycle, which is essential for tissue reconstruction and wound healing after photodestruction of tumor tissue. The prompted results reported in the current study imply the promising potential of CsxWO3 nanorods for application in PTA cancer therapy. Electronic supplementary information (ESI) available: EDS spectra, XRD patterns, TG plot of CsxWO3 nanorod are provided in the ESI. Additionally, linear correlations between NIR absorbance and CsxWO3-PEGS nanorod concentrations, cytotoxicity results, TEM image of intracellular distribution of CsxWO3-PEGS nanorods and fluorescence images can be found in the ESI. See DOI: 10.1039/c3nr01025b

Assessment of penetration potential of pH responsive double walled biodegradable nanogels coated with eucalyptus oil for the controlled delivery of 5-fluorouracil: In vitro and ex vivo studies.

PubMed

Sahu, Prashant; Kashaw, Sushil K; Jain, Sanyog; Sau, Samaresh; Iyer, Arun K

2017-05-10

Penetration enhancers coated biodegradable polymeric nanogels loaded with cytotoxic drugs applied via the topical route, can be a promising strategy for improving the chemotherapeutic efficiency of skin cancers. The major objective of proposed research was to investigate the in vitro and ex vivo chemotherapeutic potential of double walled PLGA-chitosan biodegradable nanogel entrapped with 5-fluororuacil (5-FU) coated with eucalyptus oil, topically applied onto the skin. 5-FU was first entrapped in PLGA core by solvent evaporation technique followed by coating with cationic chitosan for ionic interaction with anionic skin cancer cell membrane. A surface coating of eucalyptus oil (1%) was employed to improve the penetration efficacy of the nanogel into stratum corneum. The surface modified biodegradable double walled nanogel was characterized for particle size, charge and thermal properties followed by pH dependent in vitro analysis. Human keratinocyte (HaCaT) cell line was employed for the bio- and cyto-compatibility testing prior to the hemolysis assay and coagulation assessment. A porcine skin ex vivo screening was performed for assessing the penetration potential of the nanogels. DLS and TEM revealed a particle size about 170nm for the double walled nanogels. The nanogels also exhibited high thermal stability as analyzed by thermogravimetry (TG) and differential thermal analysis (DTA). The drug entrapment efficacy was about ~40%. The drug release showed sustained release pattern noted up to 24h. The low hemolysis of 2.39% with short prothrombin time (PT) and activated partial thromboplastin time (APTT) of 14.2 and 35.5s respectively, revealed high biocompatibility of the nanogels. The cellular uptake and localization was assessed by confocal microscopy. The cytotoxicity (MTT assay) on HaCaT cell line demonstrated high cytocompatibilty of the nanogels. An ex vivo evaluation using porcine skin displayed efficient and steady state flux of 5-FU from the biodegradable nanogles into the skin, while the histology of the porcine skin revealed enhanced penetration potential of eucalyptus oil coated PLGA-chitosan double walled nanogels. Taken together the in vivo and ex vivo results portend promising potential for the utility of the biodegradable nanogels for treating skin cancers. Copyright © 2017. Published by Elsevier B.V.

Intervention on toll-like receptors in pancreatic cancer.

PubMed

Vaz, Juan; Andersson, Roland

2014-05-21

Pancreatic ductal adenocarcinoma (PDA) is a devastating disease with pronounced morbidity and a high mortality rate. Currently available treatments lack convincing cost-efficiency determinations and are in most cases not associated with relevant success rate. Experimental stimulation of the immune system in murine PDA models has revealed some promising results. Toll-like receptors (TLRs) are pillars of the immune system that have been linked to several forms of malignancy, including lung, breast and colon cancer. In humans, TLRs are expressed in the pancreatic cancer tissue and in several cancer cell lines, whereas they are not expressed in the normal pancreas. In the present review, we explore the current knowledge concerning the role of different TLRs associated to PDA. Even if almost all known TLRs are expressed in the pancreatic cancer microenvironment, there are only five TLRs suggested as possible therapeutic targets. Most data points at TLR2 and TLR9 as effective tumor markers and agonists could potentially be used as e.g. future adjuvant therapies. The elucidation of the role of TLR3 in PDA is only in its initial phase. The inhibition/blockage of TLR4-related pathways has shown some promising effects, but there are still many steps left before TLR4 inhibitors can be considered as possible therapeutic agents. Finally, TLR7 antagonists seem to be potential candidates for therapy. Independent of their potential in immunotherapies, all existing data indicate that TLRs are strongly involved in the pathophysiology and development of PDA.

Biosurfactants: Promising Molecules for Petroleum Biotechnology Advances.

PubMed

De Almeida, Darne G; Soares Da Silva, Rita de Cássia F; Luna, Juliana M; Rufino, Raquel D; Santos, Valdemir A; Banat, Ibrahim M; Sarubbo, Leonie A

2016-01-01

The growing global demand for sustainable technologies that improves the efficiency of petrochemical processes in the oil industry has driven advances in petroleum biotechnology in recent years. Petroleum industry uses substantial amounts of petrochemical-based synthetic surfactants in its activities as mobilizing agents to increase the availability or recovery of hydrocarbons as well as many other applications related to extraction, treatment, cleaning, and transportation. However, biosurfactants have several potential applications for use across the oil processing chain and in the formulations of petrochemical products such as emulsifying/demulsifying agents, anticorrosive, biocides for sulfate-reducing bacteria, fuel formulation, extraction of bitumen from tar sands, and many other innovative applications. Due to their versatility and proven efficiency, biosurfactants are often presented as valuable versatile tools that can transform and modernize petroleum biotechnology in an attempt to provide a true picture of state of the art and directions or use in the oil industry. We believe that biosurfactants are going to have a significant role in many future applications in the oil industries and in this review therefore, we highlight recent important relevant applications, patents disclosures and potential future applications for biosurfactants in petroleum and related industries.

Gas release-based prescreening combined with reversed-phase HPLC quantitation for efficient selection of high-γ-aminobutyric acid (GABA)-producing lactic acid bacteria.

PubMed

Wu, Qinglong; Shah, Nagendra P

2015-02-01

High γ-aminobutyric acid (GABA)-producing lactobacilli are promising for the manufacture of GABA-rich foods and to synthesize GRAS (generally recognized as safe)-grade GABA. However, common chromatography-based screening is time-consuming and inefficient. In the present study, Korean kimchi was used as a model of lactic acid-based fermented foods, and a gas release-based prescreening of potential GABA producers was developed. The ability to produce GABA by potential GABA producers in de Man, Rogosa, and Sharpe medium supplemented with or without monosodium glutamate was further determined by HPLC. Based on the results, 9 isolates were regarded as high GABA producers, and were further genetically identified as Lactobacillus brevis based on the sequences of 16S rRNA gene. Gas release-based prescreening combined with reversed-phase HPLC confirmation was an efficient and cost-effective method to identify high-GABA-producing LAB, which could be good candidates for probiotics. The GABA that is naturally produced by these high-GABA-producing LAB could be used as a food additive. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Magnetic hyaluronic acid nanospheres via aqueous Diels-Alder chemistry to deliver dexamethasone for adipose tissue engineering.

PubMed

Jia, Yang; Fan, Ming; Chen, Huinan; Miao, Yuting; Xing, Lian; Jiang, Bohong; Cheng, Qifan; Liu, Dongwei; Bao, Weikang; Qian, Bin; Wang, Jionglu; Xing, Xiaodong; Tan, Huaping; Ling, Zhonghua; Chen, Yong

2015-11-15

Biopolymer-based nanospheres have great potential in the field of drug delivery and tissue regenerative medicine. In this work, we present a flexible way to conjugate a magnetic hyaluronic acid (HA) nanosphere system that are capable of vectoring delivery of adipogenic factor, e.g. dexamethasone, for adipose tissue engineering. Conjugation of nanospheres was established by aqueous Diels-Alder chemistry between furan and maleimide of HA derivatives. Simultaneously, a furan functionalized dexamethasone peptide, GQPGK, was synthesized and covalently immobilized into the nanospheres. The magnetic HA nanospheres were fabricated by encapsulating super-paramagnetic iron oxide nanoparticles, which exhibited quick magnetic sensitivity. The aqueous Diels-Alder chemistry made nanospheres high binding efficiency of dexamethasone, and the vectoring delivery of dexamethasone could be easily controlled by a external magnetic field. The potential application of the magnetic HA nanospheres on vectoring delivery of adipogenic factor was confirmed by co-culture of human adipose-derived stem cells (ASCs). In vitro cytotoxicity tests demonstrated that incorporation of dexamethasone into magnetic HA nanospheres showed high efficiency to promote ASCs viabilities, in particular under a magnetic field, which suggested a promising future for adipose regeneration applications. Copyright © 2015 Elsevier Inc. All rights reserved.

Influence of cationic lipid concentration on properties of lipid–polymer hybrid nanospheres for gene delivery

PubMed Central

Bose, Rajendran JC; Arai, Yoshie; Ahn, Jong Chan; Park, Hansoo; Lee, Soo-Hong

2015-01-01

Nanoparticles have been widely used for nonviral gene delivery. Recently, cationic hybrid nanoparticles consisting of two different materials were suggested as a promising delivery vehicle. In this study, nanospheres with a poly(d,l-lactic-co-glycolic acid) (PLGA) core and cationic lipid shell were prepared, and the effect of cationic lipid concentrations on the properties of lipid polymer hybrid nanocarriers investigated. Lipid–polymer hybrid nanospheres (LPHNSs) were fabricated by the emulsion-solvent evaporation method using different concentrations of cationic lipids and characterized for size, surface charge, stability, plasmid DNA-binding capacity, cytotoxicity, and transfection efficiency. All LPHNSs had narrow size distribution with positive surface charges (ζ-potential 52–60 mV), and showed excellent plasmid DNA-binding capacity. In vitro cytotoxicity measurements with HEK293T, HeLa, HaCaT, and HepG2 cells also showed that LPHNSs exhibited less cytotoxicity than conventional transfection agents, such as Lipofectamine and polyethyleneimine–PLGA. As cationic lipid concentrations increased, the particle size of LPHNSs decreased while their ζ-potential increased. In addition, the in vitro transfection efficiency of LPHNSs increased as lipid concentration increased. PMID:26379434

Photosynthetic Energy Conversion Efficiency: Setting a Baseline for Gauging Future Improvements in Important Food and Biofuel Crops1

PubMed Central

2015-01-01

The conversion efficiency (εc) of absorbed radiation into biomass (MJ of dry matter per MJ of absorbed photosynthetically active radiation) is a component of yield potential that has been estimated at less than half the theoretical maximum. Various strategies have been proposed to improve εc, but a statistical analysis to establish baseline εc levels across different crop functional types is lacking. Data from 164 published εc studies conducted in relatively unstressed growth conditions were used to determine the means, greatest contributors to variation, and genetic trends in εc across important food and biofuel crop species. εc was greatest in biofuel crops (0.049–0.066), followed by C4 food crops (0.046–0.049), C3 nonlegumes (0.036–0.041), and finally C3 legumes (0.028–0.035). Despite confining our analysis to relatively unstressed growth conditions, total incident solar radiation and average growing season temperature most often accounted for the largest portion of εc variability. Genetic improvements in εc, when present, were less than 0.7% per year, revealing the unrealized potential of improving εc as a promising contributing strategy to meet projected future agricultural demand. PMID:25829463

Biosurfactants: Promising Molecules for Petroleum Biotechnology Advances

PubMed Central

De Almeida, Darne G.; Soares Da Silva, Rita de Cássia F.; Luna, Juliana M.; Rufino, Raquel D.; Santos, Valdemir A.; Banat, Ibrahim M.; Sarubbo, Leonie A.

2016-01-01

The growing global demand for sustainable technologies that improves the efficiency of petrochemical processes in the oil industry has driven advances in petroleum biotechnology in recent years. Petroleum industry uses substantial amounts of petrochemical-based synthetic surfactants in its activities as mobilizing agents to increase the availability or recovery of hydrocarbons as well as many other applications related to extraction, treatment, cleaning, and transportation. However, biosurfactants have several potential applications for use across the oil processing chain and in the formulations of petrochemical products such as emulsifying/demulsifying agents, anticorrosive, biocides for sulfate-reducing bacteria, fuel formulation, extraction of bitumen from tar sands, and many other innovative applications. Due to their versatility and proven efficiency, biosurfactants are often presented as valuable versatile tools that can transform and modernize petroleum biotechnology in an attempt to provide a true picture of state of the art and directions or use in the oil industry. We believe that biosurfactants are going to have a significant role in many future applications in the oil industries and in this review therefore, we highlight recent important relevant applications, patents disclosures and potential future applications for biosurfactants in petroleum and related industries. PMID:27843439

[Nurse-led in Primary Health Care setting: a well-timed and promising organizational innovation].

PubMed

Torres-Ricarte, Marc; Crusat-Abelló, Ernest; Peñuelas-Rodríguez, Silvia; Zabaleta-del-Olmo, Edurne

2015-01-01

At present, the severe economic crisis along with the increasing prevalence of chronic diseases is leading to different countries to consider updating their Primary Health Care (PHC) services in order to make them more efficient and reduce health inequalities. To that end, various initiatives are being carried out, such as the provision of Nurse-led services and interventions. The purpose of this article is to present the available knowledge, controversies and opportunities for Nurse-led initiatives in the setting of PHC. Nurse- led interventions or health services in PHC have proven to be equal or more effective than usual care in disease prevention, the routine follow-up of patients with chronic conditions, and first contact care for people with minor illness. However, as there are only a few health economic evaluation studies published their efficiency is still potential. In conclusion, the Nurse-led care could be an innovative organizational initiative with the potential to provide an adequate response to the contemporary health needs of the population, as well as an opportunity for the nursing profession and for PHC and health systems in general. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

Beyond insects: current status, achievements and future perspectives of RNAi in mite pests.

PubMed

Niu, Jinzhi; Shen, Guangmao; Christiaens, Olivier; Smagghe, Guy; He, Lin; Wang, Jinjun

2018-05-11

Mites comprise a group of key agricultural pests on a wide range of crops. They cause harm through feeding on the plant and transferring dangerous pathogens, and the rapid evolution of pesticide resistance in mites highlights the need for novel control methods. Currently, RNA interference (RNAi) shows a great potential for insect pest control. Here, we review the literature associated with RNAi in mite pests. We discuss different target genes and RNAi efficiency in various mite species, a promising Varroa control program through RNAi, the synergy of RNAi with plant defense mechanisms and microorganisms, and the current understandings of systemic movement of dsRNA. Based on this, we can conclude that there is a clear potential for an RNAi-based mite control application but further research on several aspects is needed, including: (i) the factors influencing the RNAi efficiency, (ii) the mechanism of environmental RNAi and cross-kingdom dsRNA trafficking, (iii) the mechanism of possible systemic and parental RNAi, and (iv) non-target effects, specifically in predatory mites, should be considered during the RNAi target selection. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

SiRNA Crosslinked Nanoparticles for the Treatment of Inflammation-induced Liver Injury.

PubMed

Tang, Yaqin; Zeng, Ziying; He, Xiao; Wang, Tingting; Ning, Xinghai; Feng, Xuli

2017-02-01

RNA interference mediated by small interfering RNA (siRNA) provides a powerful tool for gene regulation, and has a broad potential as a promising therapeutic strategy. However, therapeutics based on siRNA have had limited clinical success due to their undesirable pharmacokinetic properties. This study presents pH-sensitive nanoparticles-based siRNA delivery systems (PNSDS), which are positive-charge-free nanocarriers, composed of siRNA chemically crosslinked with multi-armed poly(ethylene glycol) carriers via acid-labile acetal linkers. The unique siRNA crosslinked structure of PNSDS allows it to have minimal cytotoxicity, high siRNA loading efficiency, and a stimulus-responsive property that enables the selective intracellular release of siRNA in response to pH conditions. This study demonstrates that PNSDS can deliver tumor necrosis factor alpha (TNF-α) siRNA into macrophages and induce the efficient down regulation of the targeted gene in complete cell culture media. Moreover, PNSDS with mannose targeting moieties can selectively accumulate in mice liver, induce specific inhibition of macrophage TNF-α expression in vivo, and consequently protect mice from inflammation-induced liver damages. Therefore, this novel siRNA delivering platform would greatly improve the therapeutic potential of RNAi based therapies.

Preparation and Characterization of Nanoparticle β-Cyclodextrin:Geraniol Inclusion Complexes.

PubMed

Hadian, Zahra; Maleki, Majedeh; Abdi, Khosro; Atyabi, Fatemeh; Mohammadi, Abdoreza; Khaksar, Ramin

2018-01-01

The aim of the present study was to formulate β-cyclodextrin (β-CD) nanoparticles loaded with geraniol (GR) essential oil (EO) with appropriate physicochemical properties. Complexation of GR with β-CD was optimized by evaluation of four formulations, using the co-precipitation method, and the encapsulation efficiency (EE), loading, size, particle size distribution (PDI) and zeta potential were investigated. Further characterization was performed with nuclear magnetic resonance spectroscopy ( 1 H NMR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and infra-red (IR) spectroscopy analysis. Results showed that the physicochemical properties of the nanoparticles were affected by GR content in formulations that yielded nanoscale-size particles ranging from 111 to 258 nm. The highest encapsulation efficiency (79.4 ± 5.4%) was obtained when the molar ratio of EO to β-CD was 0.44: 0.13 with negative zeta potential (-21.1 ± 0.5 mV). The 1 H-NMR spectrum confirmed the formation structure of the EO and β-CD nanoparticle complex. Complexation with geraniol resulted in changes of IR profile, NMR chemical shifts, DSC properties, and SEM of β-cyclodextrin. Inclusion complex of essential oil with β-cyclodextrin was considered as promising bioactive materials for designing functional food.

Preparation and Characterization of Nanoparticle β-Cyclodextrin:Geraniol Inclusion Complexes

PubMed Central

Hadian, Zahra; Maleki, Majedeh; Abdi, Khosro; Atyabi, Fatemeh; Mohammadi, Abdoreza; Khaksar, Ramin

2018-01-01

The aim of the present study was to formulate β-cyclodextrin (β-CD) nanoparticles loaded with geraniol (GR) essential oil (EO) with appropriate physicochemical properties. Complexation of GR with β-CD was optimized by evaluation of four formulations, using the co-precipitation method, and the encapsulation efficiency (EE), loading, size, particle size distribution (PDI) and zeta potential were investigated. Further characterization was performed with nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and infra-red (IR) spectroscopy analysis. Results showed that the physicochemical properties of the nanoparticles were affected by GR content in formulations that yielded nanoscale-size particles ranging from 111 to 258 nm. The highest encapsulation efficiency (79.4 ± 5.4%) was obtained when the molar ratio of EO to β-CD was 0.44: 0.13 with negative zeta potential (-21.1 ± 0.5 mV). The 1H-NMR spectrum confirmed the formation structure of the EO and β-CD nanoparticle complex. Complexation with geraniol resulted in changes of IR profile, NMR chemical shifts, DSC properties, and SEM of β-cyclodextrin. Inclusion complex of essential oil with β-cyclodextrin was considered as promising bioactive materials for designing functional food.

A metro-access integrated network with all-optical virtual private network function using DPSK/ASK modulation format

NASA Astrophysics Data System (ADS)

Tian, Yue; Leng, Lufeng; Su, Yikai

2008-11-01

All-optical virtual private network (VPN), which offers dedicated optical channels to connect users within a VPN group, is considered a promising approach to efficient internetworking with low latency and enhanced security implemented in the physical layer. On the other hand, time-division multiplexed (TDM) / wavelength-division multiplexed (WDM) network architecture based on a feeder-ring with access-tree topology, is considered a pragmatic migration scenario from current TDM-PONs to future WDM-PONs and a potential convergence scheme for access and metropolitan networks, due to its efficiently shared hardware and bandwidth resources. All-optical VPN internetworking in such a metro-access integrated structure is expected to cover a wider service area and therefore is highly desirable. In this paper, we present a TDM/WDM metro-access integrated network supporting all-optical VPN internetworking among ONUs in different sub- PONs based on orthogonal differential-phase-shift keying (DPSK) / amplitude-shift keying (ASK) modulation format. In each ONU, no laser but a single Mach-Zehnder modulator (MZM) is needed for the upstream and VPN signal generation, which is cost-effective. Experiments and simulations are performed to verify its feasibility as a potential solution to the future access service.

Dual-Functional Hydrazide-Reactive and Anhydride-Containing Oligomeric Hydrogel Building Blocks.

PubMed

Kascholke, Christian; Loth, Tina; Kohn-Polster, Caroline; Möller, Stephanie; Bellstedt, Peter; Schulz-Siegmund, Michaela; Schnabelrauch, Matthias; Hacker, Michael C

2017-03-13

Biomimetic hydrogels are advanced biomaterials that have been developed following different synthetic routes. Covalent postfabrication functionalization is a promising strategy to achieve efficient matrix modification decoupled of general material properties. To this end, dual-functional macromers were synthesized by free radical polymerization of maleic anhydride with diacetone acrylamide (N-(1,1-dimethyl-3-oxobutyl)acrylamide) and pentaerythritol diacrylate monostearate. Amphiphilic oligomers (M n < 7.5 kDa) with anhydride contents of 7-20% offered cross-linking reactivity to yield rigid hydrogels with gelatinous peptides (E = 4-13 kPa) and good cell adhesion properties. Mildly reactive methyl ketones as second functionality remained intact during hydrogel formation and potential of covalent matrix modification was shown using hydrazide and hydrazine model compounds. Successful secondary dihydrazide cross-linking was demonstrated by an increase of hydrogel stiffness (>40%). Efficient hydrazide/hydrazine immobilization depending on solution pH, hydrogel ketone content as well as ligand concentration for bioconjugation was shown and reversibility of hydrazone formation was indicated by physiologically relevant hydrazide release over 7 days. Proof-of-concept experiments with hydrazido-functionalized hyaluronan demonstrated potential for covalent aECM immobilization. The presented dual-functional macromers have perspective as reactive hydrogel building blocks for various biomedical applications.

AVION: A detailed report on the preliminary design of a 79-passenger, high-efficiency, commercial transport aircraft

NASA Technical Reports Server (NTRS)

Mayfield, William; Perkins, Brett; Rogan, William; Schuessler, Randall; Stockert, Joe

1990-01-01

The Avion is the result of an investigation into the preliminary design for a high-efficiency commercial transport aircraft. The Avion is designed to carry 79 passengers and a crew of five through a range of 1,500 nm at 455 kts (M=0.78 at 32,000 ft). It has a gross take-off weight of 77,000 lb and an empty weight of 42,400 lb. Currently there are no American-built aircraft designed to fit the 60 to 90 passenger, short/medium range marketplace. The Avion gathers the premier engineering achievements of flight technology and integrates them into an aircraft which will challenge the current standards of flight efficiency, reliability, and performance. The Avion will increase flight efficiency through reduction of structural weight and the improvement of aerodynamic characteristics and propulsion systems. Its design departs from conventional aircraft design tradition with the incorporation of a three-lifting-surface (or tri-wing) configuration. Further aerodynamic improvements are obtained through modest main wing forward sweeping, variable incidence canards, aerodynamic coupling between the canard and main wing, leading edge extensions, winglets, an aerodynamic tailcone, and a T-tail empennage. The Avion is propelled by propfans, which are one of the most promising developments for raising propulsive efficiencies at high subsonic Mach numbers. Special attention is placed on overall configuration, fuselage layout, performance estimations, component weight estimations, and planform design. Leading U.S. technology promises highly efficient flight for the 21st century; the Avion will fulfill this promise to passenger transport aviation.

Non-destructive soil amendment application techniques on heavy metal-contaminated grassland: Success and long-term immobilising efficiency.

PubMed

Friesl-Hanl, Wolfgang; Platzer, Klaus; Riesing, Johann; Horak, Othmar; Waldner, Georg; Watzinger, Andrea; Gerzabek, Martin H

2017-01-15

Extensive contamination of grassland with cadmium (Cd), lead (Pb) and zinc (Zn) is a typical problem close to Pb/Zn smelter sites. The entry of Cd or Pb into the food chain is very likely, as are toxicity effects of Zn in plants. Previous promising results from pot and field experiments showed the high potential of using amendments for immobilisation to reduce metal input into the food chain via crops grown on smelter-contaminated soils at Arnoldstein (Austria) (Friesl et al., 2006). The aim of this study was to find a practical solution for large-scale contaminations in hilly regions that avoids erosion. Field application of amendments without destroying the vegetation cover (grassland) involved two approaches: (a) slurrying (Slu) the amendments into cut gaps in the vegetation cover and (b) injecting (Inj) the amendments through the vegetation cover. Here, we investigate the immobilising and long-term efficiency of treatments [gravel sludge (2.5%) + red mud (0.5%) (GS + RM)]. Risk assessment was based on soil, plant and water samples taken over a period of 10 years. Ammonium-nitrate-extractable Cd was reduced up to 50%, Pb up to 90%, and Zn over 90%. Plant uptake into the grass mixture and narrow leaf plantain was significantly reduced for Cd, Pb, and Zn. Harvesting early in vegetation period can further reduce uptake and meet the threshold for fodder crops. The reduction of these elements in the seepage water in 24 samplings within these 10 years reached 40%, 45% and 50%, respectively. Immobilisation increased microbial biomass and decreased human bioaccessibility for Pb. Our investigation of the long-term efficiency of GS + RM in all treatments shows that the Slu and Inj amendment application techniques have promising potential as a realistic and practical method for extensively contaminated hilly land. Slurrying performed best. We conclude that grassland remediation methods involving tillage are counterproductive from the viewpoint of bioaccessibility and soil protection and therefore should be avoided. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance of a Cylindrical Hall-Effect Thruster with Magnetic Field Generated by Permanent Magnets

NASA Technical Reports Server (NTRS)

Polzin, Kurt A.; Raitses, Yevgeny; Fisch, Nathaniel J.

2008-01-01

While Hall thrusters can operate at high efficiency at kW power levels, it is difficult to construct one that operates over a broad envelope down to 100W while maintaining an efficiency of 45- 55%. Scaling to low power while holding the main dimensionless parameters constant requires a decrease in the thruster channel size and an increase in the magnetic field strength. Increasing the magnetic field becomes technically challenging since the field can saturate the miniaturized inner components of the magnetic circuit and scaling down the magnetic circuit leaves very little room for magnetic pole pieces and heat shields. An alternative approach is to employ a cylindrical Hall thruster (CHT) geometry. Laboratory model CHTs have operated at power levels ranging from the order of 50 Watts up to 1 kW. These thrusters exhibit performance characteristics which are comparable to conventional, annular Hall thrusters of similar size. Compared to the annular Hall thruster, the CHT has a lower insulator surface area to discharge chamber volume ratio. Consequently, there is the potential for reduced wall losses in the channel of a CHT, and any reduction in wall losses should translate into lower channel heating rates and reduced erosion. This makes the CHT geometry promising for low-power applications. Recently, a CHT that uses permanent magnets to produce the magnetic field topology was tested. This thruster has the promise of reduced power consumption over previous CHT iterations that employed electromagnets. Data are presented for two purposes: to expose the effect different controllable parameters have on the discharge and to summarize performance measurements (thrust, Isp, efficiency) obtained using a thrust stand. These data are used to gain insight into the thruster's operation and to allow for quantitative comparisons between the permanent magnet CHT and the electromagnet CHT.

Facile one-pot synthesis of cellulose nanocrystal-supported hollow CuFe2O4 nanoparticles as efficient catalyst for 4-nitrophenol reduction

NASA Astrophysics Data System (ADS)

Zhang, Sufeng; Zhao, Dongyan; Hou, Chen; Liang, Chen; Li, Hao

2018-06-01

A facile and efficient one-pot method for the synthesis of well-dispersed hollow CuFe2O4 nanoparticles (H-CuFe2O4 NPs) in the presence of cellulose nanocrystals (CNC) as the support was described. Based on the one-pot solvothermal condition control, magnetic H-CuFe2O4 NPs were in-situ grown on the CNC surface uniformly. TEM images indicated good dispersity of H-CuFe2O4 NPs with uniform size of 300 nm. The catalytic activity of H-CuFe2O4/CNC was tested in the catalytic reduction of 4-nitrophenol (4-NP) in aqueous solution. Compared with most CNC-based ferrite catalysts, H-CuFe2O4/CNC catalyst exhibited an excellent catalytic activity toward the reduction of 4-NP. The catalytic performance of H-CuFe2O4/CNC catalyst was remarkably enhanced with the rate constant of 3.24 s-1 g-1, which was higher than H-CuFe2O4 NPs (0.50 s-1 g-1). The high catalytic activity was attributed to the introduction of CNC and the special hollow mesostructure of H-CuFe2O4 NPs. In addition, the H-CuFe2O4/CNC catalyst promised good conversion efficiency without significant decrease even after 10 cycles, confirming relatively high stability. Because of its environmental sustainability and magnetic separability, H-CuFe2O4/CNC catalyst was shown to indicate that the ferrite nanoparticles supported on CNC were acted as a promising catalyst and exhibited potential applications in numerous ferrite based catalytic reactions.

Optimized adipose tissue engineering strategy based on a neo-mechanical processing method.

PubMed

He, Yunfan; Lin, Maohui; Wang, Xuecen; Guan, Jingyan; Dong, Ziqing; Feng, Lu; Xing, Malcolm; Feng, Chuanbo; Li, Xiaojian

2018-05-26

Decellularized adipose tissue (DAT) represents a promising scaffold for adipose tissue engineering. However, the unique and prolonged lipid removal process required for adipose tissue can damage extracellular matrix (ECM) constituents. Moreover, inadequate vascularization limits the recellularization of DAT in vivo. We proposed a neo-mechanical protocol for rapidly breaking adipocytes and removing lipid content from adipose tissue. The lipid-depleted adipose tissue was then subjected to a fast and mild decellularization to fabricate high-quality DAT (M-DAT). Adipose liquid extract (ALE) derived from this mechanical process was collected and incorporated into M-DAT to further optimize in vivo recellularization. Ordinary DAT was fabricated and served as a control. This developed strategy was evaluated based on decellularization efficiency, ECM quality, and recellularization efficiency. Angiogenic factor components and angiogenic potential of ALE were evaluated in vivo and in vitro. M-DAT achieved the same decellularization efficiency, but exhibited better retention of ECM components and recellularization, compared to those with ordinary DAT. Protein quantification revealed considerable levels of angiogenic factors (basic fibroblast growth factor, epidermal growth factor, transforming growth factor-β1, and vascular endothelial growth factor) in ALE. ALE promoted tube formation in vitro and induced intense angiogenesis in M-DAT in vivo; furthermore, higher expression of the adipogenic factor PPARγ and greater numbers of adipocytes were evident following ALE treatment, compared to those in the M-DAT group. Mechanical processing of adipose tissue led to the production of high-quality M-DAT and angiogenic factor-enriched ALE. The combination of ALE and M-DAT could be a promising strategy for engineered adipose tissue construction. This article is protected by copyright. All rights reserved. © 2018 by the Wound Healing Society.

Synthesis of protein-coated biocompatible methotrexate-loaded PLA-PEG-PLA nanoparticles for breast cancer treatment

PubMed Central

Massadeh, Salam; Alaamery, Manal; Al-Qatanani, Shatha; Alarifi, Saqer; Bawazeer, Shahad; Alyafee, Yusra

2016-01-01

Background PLA-PEG-PLA triblock polymer nanoparticles are promising tools for targeted dug delivery. The main aim in designing polymeric nanoparticles for drug delivery is achieving a controlled and targeted release of a specific drug at the therapeutically optimal rate and choosing a suitable preparation method to encapsulate the drug efficiently, which depends mainly on the nature of the drug (hydrophilic or hydrophobic). In this study, methotrexate (MTX)-loaded nanoparticles were prepared by the double emulsion method. Method Biodegradable polymer polyethylene glycol-polylactide acid tri-block was used with poly(vinyl alcohol) as emulsifier. The resulting methotrexate polymer nanoparticles were coated with bovine serum albumin in order to improve their biocompatibility. This study focused on particle size distribution, zeta potential, encapsulation efficiency, loading capacity, and in vitro drug release at various concentrations of PVA (0.5%, 1%, 2%, and 3%). Results Reduced particle size of methotrexate-loaded nanoparticles was obtained using lower PVA concentrations. Enhanced encapsulation efficiency and loading capacity was obtained using 1% PVA. FT-IR characterization was conducted for the void polymer nanoparticles and for drug-loaded nanoparticles with methotrexate, and the protein-coated nanoparticles in solid state showed the structure of the plain PEG-PLA and the drug-loaded nanoparticles with methotrexate. The methotrexate-loaded PLA-PEG-PLA nanoparticles have been studied in vitro; the drug release, drug loading, and yield are reported. Conclusion The drug release profile was monitored over a period of 168 hours, and was free of burst effect before the protein coating. The results obtained from this work are promising; this work can be taken further to develop MTX based therapies.

A dual strategy to improve the penetration and treatment of breast cancer by combining shrinking nanoparticles with collagen depletion by losartan.

PubMed

Cun, Xingli; Ruan, Shaobo; Chen, Jiantao; Zhang, Li; Li, Jianping; He, Qin; Gao, Huile

2016-02-01

Although development of nanomedicines has been a promising direction in tumor treatment, the therapeutic outcome of current nanomedicines is unsatisfying, partly because of the poor retention and penetration in tumors. Recently, a kind of tumor microenvironment sensitive size shrinkable nanoparticles (DOX-AuNPs-GNPs) has been developed by our lab, which could enhance the tumor penetration and retention depending on the size shrinking. However, the further enhancement is still restricted by dense collagen network in tumors. Thus in this study, we combined DOX-AuNPs-GNPs with losartan to deplete tumor collagen (constituted up to 90% of extracellular matrix) to further improve tumor penetration. In vitro, DOX-AuNPs-GNPs can shrink from over 117.8nm to less than 50.0nm and release DOX-AuNPs under the triggering of tumor overexpressed matrix metalloproteinases-2 (MMP-2). In vivo, pretreatment with losartan significantly decrease the collagen level and improve the tumor penetration. In combination, losartan combined with DOX-AuNPs-GNPs showed the best drug delivery efficiency, striking penetration efficiency and best 4T1 breast tumor inhibition effect. In conclusion, this study provided a promising synergetic strategy to improve the tumor treatment efficiency of nanomedicines. We have developed a dual strategy for deep tumor penetration through combining size shrinkable DOX-AuNPs-GNPs with depleting tumor collagen by losartan. Additionally, we demonstrate therapeutic efficacy in breast tumor bearing mouse model. DOX-AuNPs-GNPs co-administration with losartan is a novel and highly attractive strategy for anti-tumor drug delivery with the potential for broad applications in clinic. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Enabling iron pyrite (FeS2) and related ternary pyrite compounds for high-performance solar energy applications

NASA Astrophysics Data System (ADS)

Caban Acevedo, Miguel

The success of solar energy technologies depends not only on highly efficient solar-to-electrical energy conversion, charge storage or chemical fuel production, but also on dramatically reduced cost, to meet the future terawatt energy challenges we face. The enormous scale involved in the development of impactful solar energy technologies demand abundant and inexpensive materials, as well as energy-efficient and cost-effective processes. As a result, the investigation of semiconductor, catalyst and electrode materials made of earth-abundant and sustainable elements may prove to be of significant importance for the long-term adaptation of solar energy technologies on a larger scale. Among earth-abundant semiconductors, iron pyrite (cubic FeS2) has been considered the most promising solar energy absorber with the potential to achieve terawatt energy-scale deployment. Despite extensive synthetic progress and device efforts, the solar conversion efficiency of iron pyrite has remained below 3% since the 1990s, primarily due to a low open circuit voltage (V oc). The low photovoltage (Voc) of iron pyrite has puzzled scientists for decades and limited the development of cost-effective solar energy technologies based on this otherwise promising semiconductor. Here I report a comprehensive investigation of the syntheses and properties of iron pyrite materials, which reveals that the Voc of iron pyrite is limited by the ionization of a high density of intrinsic bulk defect states despite high density surface states and strong surface Fermi level pinning. Contrary to popular belief, bulk defects most-likely caused by intrinsic sulfur vacancies in iron pyrite must be controlled in order to enable this earth-abundant semiconductor for cost-effective and sustainable solar energy conversion. Lastly, the investigation of iron pyrite presented here lead to the discovery of ternary pyrite-type cobalt phosphosulfide (CoPS) as a highly-efficient earth-abundant catalyst material for electrochemical and solar energy driven hydrogen production.

Engineering Streptomyces coelicolor Carbonyl Reductase for Efficient Atorvastatin Precursor Synthesis

PubMed Central

Li, Min; Zhang, Zhi-Jun; Kong, Xu-Dong; Yu, Hui-Lei

2017-01-01

ABSTRACT Streptomyces coelicolor CR1 (ScCR1) has been shown to be a promising biocatalyst for the synthesis of an atorvastatin precursor, ethyl-(S)-4-chloro-3-hydroxybutyrate [(S)-CHBE]. However, limitations of ScCR1 observed for practical application include low activity and poor stability. In this work, protein engineering was employed to improve the catalytic efficiency and stability of ScCR1. First, the crystal structure of ScCR1 complexed with NADH and cosubstrate 2-propanol was solved, and the specific activity of ScCR1 was increased from 38.8 U/mg to 168 U/mg (ScCR1I158V/P168S) by structure-guided engineering. Second, directed evolution was performed to improve the stability using ScCR1I158V/P168S as a template, affording a triple mutant, ScCR1A60T/I158V/P168S, whose thermostability (T5015, defined as the temperature at which 50% of initial enzyme activity is lost following a heat treatment for 15 min) and substrate tolerance (C5015, defined as the concentration at which 50% of initial enzyme activity is lost following incubation for 15 min) were 6.2°C and 4.7-fold higher than those of the wild-type enzyme. Interestingly, the specific activity of the triple mutant was further increased to 260 U/mg. Protein modeling and docking analysis shed light on the origin of the improved activity and stability. In the asymmetric reduction of ethyl-4-chloro-3-oxobutyrate (COBE) on a 300-ml scale, 100 g/liter COBE could be completely converted by only 2 g/liter of lyophilized ScCR1A60T/I158V/P168S within 9 h, affording an excellent enantiomeric excess (ee) of >99% and a space-time yield of 255 g liter−1 day−1. These results suggest high efficiency of the protein engineering strategy and good potential of the resulting variant for efficient synthesis of the atorvastatin precursor. IMPORTANCE Application of the carbonyl reductase ScCR1 in asymmetrically synthesizing (S)-CHBE, a key precursor for the blockbuster drug Lipitor, from COBE has been hindered by its low catalytic activity and poor thermostability and substrate tolerance. In this work, protein engineering was employed to improve the catalytic efficiency and stability of ScCR1. The catalytic efficiency, thermostability, and substrate tolerance of ScCR1 were significantly improved by structure-guided engineering and directed evolution. The engineered ScCR1 may serve as a promising biocatalyst for the biosynthesis of (S)-CHBE, and the protein engineering strategy adopted in this work would serve as a useful approach for future engineering of other reductases toward potential application in organic synthesis. PMID:28389544

Incentives for college student participation in web-based substance use surveys.

PubMed

Patrick, Megan E; Singer, Eleanor; Boyd, Carol J; Cranford, James A; McCabe, Sean Esteban

2013-03-01

The purpose of this study was to examine the effects of two incentive conditions (a $10 pre-incentive only vs. a $2 pre-incentive and a $10 promised incentive) on response rates, sample composition, substantive data, and cost-efficiency in a survey of college student substance use and related behaviors. Participants were 3000 randomly-selected college students invited to participate in a survey on substance use. Registrar data on all invitees was used to compare response rates and respondents, and web-based data collection on participants was used to compare substantive findings. Participants randomized to the pre-incentive plus promised incentive condition were more likely to complete the survey and less likely to give partial responses. Subgroup differences by sex, class year, and race were evaluated among complete responders, although only sex differences were significant. Men were more likely to respond in the pre-incentive plus promised incentive condition than the pre-incentive only condition. Substantive data did not differ across incentive structure, although the pre-incentive plus promised incentive condition was more cost-efficient. Survey research on college student populations is warranted to support the most scientifically sound and cost-efficient studies possible. Although substantive data did not differ, altering the incentive structure could yield cost savings with better response rates and more representative samples. Copyright © 2012 Elsevier Ltd. All rights reserved.

Boosting the Energy Density of Carbon-Based Aqueous Supercapacitors by Optimizing the Surface Charge.

PubMed

Yu, Minghao; Lin, Dun; Feng, Haobin; Zeng, Yinxiang; Tong, Yexiang; Lu, Xihong

2017-05-08

The voltage of carbon-based aqueous supercapacitors is limited by the water splitting reaction occurring in one electrode, generally resulting in the promising but unused potential range of the other electrode. Exploiting this unused potential range provides the possibility for further boosting their energy density. An efficient surface charge control strategy was developed to remarkably enhance the energy density of multiscale porous carbon (MSPC) based aqueous symmetric supercapacitors (SSCs) by controllably tuning the operating potential range of MSPC electrodes. The operating voltage of the SSCs with neutral electrolyte was significantly expanded from 1.4 V to 1.8 V after simple adjustment, enabling the energy density of the optimized SSCs reached twice as much as the original. Such a facile strategy was also demonstrated for the aqueous SSCs with acidic and alkaline electrolytes, and is believed to bring insight in the design of aqueous supercapacitors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alternative Fuels and Their Potential Impact on Aviation

NASA Technical Reports Server (NTRS)

Daggett, D.; Hendricks, R.; Walther, R.

2006-01-01

With a growing gap between the growth rate of petroleum production and demand, and with mounting environmental needs, the aircraft industry is investigating issues related to fuel availability, candidates for alternative fuels, and improved aircraft fuel efficiency. Bio-derived fuels, methanol, ethanol, liquid natural gas, liquid hydrogen, and synthetic fuels are considered in this study for their potential to replace or supplement conventional jet fuels. Most of these fuels present the airplane designers with safety, logistical, and performance challenges. Synthetic fuel made from coal, natural gas, or other hydrocarbon feedstock shows significant promise as a fuel that could be easily integrated into present and future aircraft with little or no modification to current aircraft designs. Alternatives, such as biofuel, and in the longer term hydrogen, have good potential but presently appear to be better suited for use in ground transportation. With the increased use of these fuels, a greater portion of a barrel of crude oil can be used for producing jet fuel because aircraft are not as fuel-flexible as ground vehicles.

Next generation bone tissue engineering: non-viral miR-133a inhibition using collagen-nanohydroxyapatite scaffolds rapidly enhances osteogenesis

NASA Astrophysics Data System (ADS)

Mencía Castaño, Irene; Curtin, Caroline M.; Duffy, Garry P.; O'Brien, Fergal J.

2016-06-01

Bone grafts are the second most transplanted materials worldwide at a global cost to healthcare systems valued over $30 billion every year. The influence of microRNAs in the regenerative capacity of stem cells offers vast therapeutic potential towards bone grafting; however their efficient delivery to the target site remains a major challenge. This study describes how the functionalisation of porous collagen-nanohydroxyapatite (nHA) scaffolds with miR-133a inhibiting complexes, delivered using non-viral nHA particles, enhanced human mesenchymal stem cell-mediated osteogenesis through the novel focus on a key activator of osteogenesis, Runx2. This study showed enhanced Runx2 and osteocalcin expression, as well as increased alkaline phosphatase activity and calcium deposition, thus demonstrating a further enhanced therapeutic potential of a biomaterial previously optimised for bone repair applications. The promising features of this platform offer potential for a myriad of applications beyond bone repair and tissue engineering, thus presenting a new paradigm for microRNA-based therapeutics.

Apoptin towards safe and efficient anticancer therapies.

PubMed

Backendorf, Claude; Noteborn, Mathieu H M

2014-01-01

The chicken anemia virus derived protein apoptin harbors cancer-selective cell killing characteristics, essentially based on phosphorylation-mediated nuclear transfer in cancer cells and efficient cytoplasmic degradation in normal cells. Here, we describe a growing set of preclinical experiments underlying the promises of the anti-cancer potential of apoptin. Various non-replicative oncolytic viral vector systems have revealed the safety and efficacy of apoptin. In addition, apoptin enhanced the oncolytic potential of adenovirus, parvovirus and Newcastle disease virus vectors. Intratumoral injection of attenuated Salmonella typhimurium bacterial strains and plasmid-based systems expressing apoptin resulted in significant tumor regression. In-vitro and in-vivo experiments showed that recombinant membrane-transferring PTD4- or TAT-apoptin proteins have potential as a future anticancer therapeutics. In xenografted hepatoma and melanoma mouse models PTD4-apoptin protein entered both cancer and normal cells, but only killed cancer cells. Combinatorial treatment of PTD4-apoptin with various (chemo)therapeutic compounds revealed an additive or even synergistic effect, reducing the side effects of the single (chemo)therapeutic treatment. Degradable polymeric nanocapsules harboring MBP-apoptin fusion-protein induced tumor-selective cell killing in-vitro and in-vivo and revealed the potential of polymer-apoptin protein vehicles as an anticancer agent.Besides its direct use as an anticancer therapeutic, apoptin research has also generated novel possibilities for drug design. The nuclear location domains of apoptin are attractive tools for targeting therapeutic compounds into the nucleus of cancer cells. Identification of cancer-related processes targeted by apoptin can potentially generate novel drug targets. Recent breakthroughs important for clinical applications are reported inferring apoptin-based clinical trials as a feasible reality.

PHYSICAL EFFECTS OCCURRING DURING GENERATION AND AMPLIFICATION OF LASER RADIATION: Enhancement of the efficiency of flashlamp-pumped lasers by conversion of the spectral composition of the exciting radiation

NASA Astrophysics Data System (ADS)

Levin, M. B.; Cherkasov, A. S.

1989-02-01

An account is given of the published investigations of ways of increasing the efficiency of flashlamp-pumped lasers by frequency conversion of the exciting radiation with the aid of luminescent filters. An analysis is made of the method for calculating the efficiency of luminescent filters absorbing short-wavelength radiation and reemitting it in the absorption region of the active medium. It is shown that the use of rhodamine 6G and other phosphors as luminescent filters can double the efficiency of neodymium glass lasers, increase the efficiency of YAG:Nd3+ lasers by a factor of 1.5, and improve the efficiency of lasers activated with Ti3+ by more than an order of magnitude. The use of luminescent filters in dye lasers can double the efficiency and make it possible to reach average output powers of hundreds of watts. Promising materials for luminescent filters are considered and margins for increasing their efficiency are analyzed. The main results are reported of studies of plasma pump-spectrum converters and it is shown that promising results can be expected by combining luminescent filters and an optimized plasma converter system in an "optical boiler" enclosure.

Porous Co3O4 nanorods anchored on graphene nanosheets as an effective electrocatalysts for aprotic Li-O2 batteries

NASA Astrophysics Data System (ADS)

Yuan, Mengwei; Yang, Yan; Nan, Caiyun; Sun, Genban; Li, Huifeng; Ma, Shulan

2018-06-01

The large over-potential during the battery operation is a great obstacle for the application of Li-O2 batteries. The porous structure and electrical conductivity of the electrocatalysts are significant for the electrocatalytic performance of Li-O2 batteries. In this work, a porous Co3O4/GN nanocomposite (Co3O4 nanorods anchored on graphene nanosheets) is prepared via a facile hydrothermal method assisted with heat treatment. The unique structure of Co3O4/GN endows efficient electrocatalystic activity for Li-O2 batteries. In comparison to the Co3O4, the Co3O4/GN demonstrates a better cycle performance showing more than 40 cycles with a 1500 mAh g-1 capacity limit strategy at a current density of 300 mA g-1, and a reduced over-potential of 110 mV at high current density (1200 mA g-1). The Co3O4/GN also displays a high initial specific capacity (7600 mAh g-1) and a good reversibility in full cycle with a coulombic efficiency of 99.8% in the first cycle. The impressed cyclability, specific capacity, rate performance, and low over-potentials indicate that the as-prepared Co3O4/GN nanocomposite is a promising catalyst candidate for reversible Li-O2 batteries.

The Potential of Solar as Alternative Energy Source for Socio-Economic Wellbeing in Rural Areas, Malaysia

NASA Astrophysics Data System (ADS)

Alam, Rashidah Zainal; Siwar, Chamhuri; Ludin, Norasikin Ahmad

Malaysia's energy sector is highly dependent on fossil fuels as a primary energy source. Economic growth and socio-economic wellbeing also rely on the utilization of energy in daily life routine. Nevertheless, the increasing cost for electricity and declining fossil fuels resources causes various negative impacts to the people and environment especially in rural areas. This prompted Malaysia to shift towards alternative energy sources such as solar energy to ensure social, economic and environmental benefits. The solar energy is one of the potential renewable energy sources in tropical countries particularly in Malaysia. The paper attempts to analyze the benefits and advantages related to energy efficiency of solar for sustainable energy use and socio economic wellbeing in rural areas, Malaysia. The paper uses secondary sources of data such as policies, regulations and research reports from relevant ministries and agencies to attain the objectives. As a signatory country to the UN Convention on Climate Change and the Kyoto Protocol, Malaysia has taken initiatives for decreasing energy dependence on oil to reduce greenhouse gas emissions (GHG) for sustainable development. The paper shows solar energy becomes one of the promising alternative energy sources to alleviate energy poverty in Malaysia for rural areas. Finally, solar energy has increased socio-economic wellbeing and develops green potential and toward achieving energy efficiency in energy sector of Malaysia by preserving environment as well as reducing carbon emission.

Maintaining Sustainability for Green Schools

ERIC Educational Resources Information Center

Kennedy, Mike

2011-01-01

The promise of sustainably designed school facilities is that they will operate more efficiently and last longer than buildings constructed in more traditional ways. But that promise comes with a big if. The payoff is delivered only if the facility managers operate and maintain the buildings in ways that adhere to sustainable strategies called for…

Groundwater resource exploration in Salem district, Tamil Nadu using GIS and remote sensing

NASA Astrophysics Data System (ADS)

Maheswaran, G.; Selvarani, A. Geetha; Elangovan, K.

2016-03-01

Since last decade, the value per barrel of potable groundwater has outpaced the value of a barrel of oil in many areas of the world. Hence, proper assessment of groundwater potential and management practices are the needs of the day. Establishing relationship between remote sensing data and hydrologic phenomenon can maximize the efficiency of water resources development projects. Present study focuses on groundwater potential assessment in Salem district, Tamil Nadu to investigate groundwater resource potential. At the same, all thematic layers important from ground water occurrence and movement point of view were digitized and integrated in the GIS environment. The weights of different parameters/themes were computed using weighed index overlay analysis (WIOA), analytic hierarchy process (AHP) and fuzzy logic technique. Through this integrated GIS analysis, groundwater prospect map of the study area was prepared qualitatively. Field verification at observation wells was used to verify identified potential zones and depth of water measured at observation wells. Generated map from weighed overlay using AHP performed very well in predicting the groundwater surface and hence this methodology proves to be a promising tool for future.

An Overview of Electron Acceptors in Microbial Fuel Cells

PubMed Central

Ucar, Deniz; Zhang, Yifeng; Angelidaki, Irini

2017-01-01

Microbial fuel cells (MFC) have recently received increasing attention due to their promising potential in sustainable wastewater treatment and contaminant removal. In general, contaminants can be removed either as an electron donor via microbial catalyzed oxidization at the anode or removed at the cathode as electron acceptors through reduction. Some contaminants can also function as electron mediators at the anode or cathode. While previous studies have done a thorough assessment of electron donors, cathodic electron acceptors and mediators have not been as well described. Oxygen is widely used as an electron acceptor due to its high oxidation potential and ready availability. Recent studies, however, have begun to assess the use of different electron acceptors because of the (1) diversity of redox potential, (2) needs of alternative and more efficient cathode reaction, and (3) expanding of MFC based technologies in different areas. The aim of this review was to evaluate the performance and applicability of various electron acceptors and mediators used in MFCs. This review also evaluated the corresponding performance, advantages and disadvantages, and future potential applications of select electron acceptors (e.g., nitrate, iron, copper, perchlorate) and mediators. PMID:28469607

Fe Isolated Single Atoms on S, N Codoped Carbon by Copolymer Pyrolysis Strategy for Highly Efficient Oxygen Reduction Reaction.

PubMed

Li, Qiheng; Chen, Wenxing; Xiao, Hai; Gong, Yue; Li, Zhi; Zheng, Lirong; Zheng, Xusheng; Yan, Wensheng; Cheong, Weng-Chon; Shen, Rongan; Fu, Ninghua; Gu, Lin; Zhuang, Zhongbin; Chen, Chen; Wang, Dingsheng; Peng, Qing; Li, Jun; Li, Yadong

2018-06-01

Heteroatom-doped Fe-NC catalyst has emerged as one of the most promising candidates to replace noble metal-based catalysts for highly efficient oxygen reduction reaction (ORR). However, delicate controls over their structure parameters to optimize the catalytic efficiency and molecular-level understandings of the catalytic mechanism are still challenging. Herein, a novel pyrrole-thiophene copolymer pyrolysis strategy to synthesize Fe-isolated single atoms on sulfur and nitrogen-codoped carbon (Fe-ISA/SNC) with controllable S, N doping is rationally designed. The catalytic efficiency of Fe-ISA/SNC shows a volcano-type curve with the increase of sulfur doping. The optimized Fe-ISA/SNC exhibits a half-wave potential of 0.896 V (vs reversible hydrogen electrode (RHE)), which is more positive than those of Fe-isolated single atoms on nitrogen codoped carbon (Fe-ISA/NC, 0.839 V), commercial Pt/C (0.841 V), and most reported nonprecious metal catalysts. Fe-ISA/SNC is methanol tolerable and shows negligible activity decay in alkaline condition during 15 000 voltage cycles. X-ray absorption fine structure analysis and density functional theory calculations reveal that the incorporated sulfur engineers the charges on N atoms surrounding the Fe reactive center. The enriched charge facilitates the rate-limiting reductive release of OH* and therefore improved the overall ORR efficiency. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cooperative Game-Based Energy Efficiency Management over Ultra-Dense Wireless Cellular Networks

PubMed Central

Li, Ming; Chen, Pengpeng; Gao, Shouwan

2016-01-01

Ultra-dense wireless cellular networks have been envisioned as a promising technique for handling the explosive increase of wireless traffic volume. With the extensive deployment of small cells in wireless cellular networks, the network spectral efficiency (SE) is improved with the use of limited frequency. However, the mutual inter-tier and intra-tier interference between or among small cells and macro cells becomes serious. On the other hand, more chances for potential cooperation among different cells are introduced. Energy efficiency (EE) has become one of the most important problems for future wireless networks. This paper proposes a cooperative bargaining game-based method for comprehensive EE management in an ultra-dense wireless cellular network, which highlights the complicated interference influence on energy-saving challenges and the power-coordination process among small cells and macro cells. Especially, a unified EE utility with the consideration of the interference mitigation is proposed to jointly address the SE, the deployment efficiency (DE), and the EE. In particular, closed-form power-coordination solutions for the optimal EE are derived to show the convergence property of the algorithm. Moreover, a simplified algorithm is presented to reduce the complexity of the signaling overhead, which is significant for ultra-dense small cells. Finally, numerical simulations are provided to illustrate the efficiency of the proposed cooperative bargaining game-based and simplified schemes. PMID:27649170

The Effect of Si and Al Concentration Ratios on the Removal of U(VI) under Hanford Site 200 Area Conditions-12115

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

Katsenovich, Yelena; Gonzalez, Nathan; Moreno-Pastor, Carol

2012-07-01

Injection of reactive gases, such as NH{sub 3}, is an innovative technique to mitigate uranium contamination in soil for a vadose zone (VZ) contaminated with radionuclides. A series of experiments were conducted to examine the effect of the concentration ratio of silicon to aluminum in the presence of various bicarbonate concentrations on the coprecipitation process of U(VI). The concentration of Al in all tests remained unchanged at 2.8 mM. Experiments showed that the removal efficiency of uranium was not significantly affected by the different bicarbonate and U(VI) concentrations tested. For the lower Si:Al molar ratios of 2:1 and 18:1, themore » removal efficiency of uranium was relatively low (≤ 8%). For the Si:Al molar ratio of 35:1, the removal efficiency of uranium was increased to an average of ∼82% for all bicarbonate concentrations tested. At higher Si:Al molar ratios (53:1 and above), a relatively high removal efficiency of U(VI), approximately 85% and higher, was observed. These results demonstrate that the U(VI) removal efficiency is more affected by the Si:Al molar ratio than by the bicarbonate concentration in solution. The results of this experiment are promising for the potential implementation of NH{sub 3} gas injection for the remediation of U(VI) -contaminated VZ. (authors)« less

Cooperative Game-Based Energy Efficiency Management over Ultra-Dense Wireless Cellular Networks.

PubMed

Li, Ming; Chen, Pengpeng; Gao, Shouwan

2016-09-13

Ultra-dense wireless cellular networks have been envisioned as a promising technique for handling the explosive increase of wireless traffic volume. With the extensive deployment of small cells in wireless cellular networks, the network spectral efficiency (SE) is improved with the use of limited frequency. However, the mutual inter-tier and intra-tier interference between or among small cells and macro cells becomes serious. On the other hand, more chances for potential cooperation among different cells are introduced. Energy efficiency (EE) has become one of the most important problems for future wireless networks. This paper proposes a cooperative bargaining game-based method for comprehensive EE management in an ultra-dense wireless cellular network, which highlights the complicated interference influence on energy-saving challenges and the power-coordination process among small cells and macro cells. Especially, a unified EE utility with the consideration of the interference mitigation is proposed to jointly address the SE, the deployment efficiency (DE), and the EE. In particular, closed-form power-coordination solutions for the optimal EE are derived to show the convergence property of the algorithm. Moreover, a simplified algorithm is presented to reduce the complexity of the signaling overhead, which is significant for ultra-dense small cells. Finally, numerical simulations are provided to illustrate the efficiency of the proposed cooperative bargaining game-based and simplified schemes.

Polyethyleneimine grafted short halloysite nanotubes for gene delivery.

PubMed

Long, Zheru; Zhang, Jun; Shen, Yan; Zhou, Changren; Liu, Mingxian

2017-12-01

Inorganic nanoparticles have attracted much attentions in gene delivery because of their desirable characteristics including low toxicity, well-controlled characteristics, high gene delivery efficiency, and multi-functionalities. Here, natural occurred halloysite nanotubes (HNTs) were developed as a novel non-viral gene vector. To increase the efficiency of endocytosis, HNTs were firstly shortened into an appropriate size (~200nm). Then polyethyleneimine (PEI) was grafted onto HNTs to bind green fluorescence protein (GFP) labeled pDNA. The structure and physical-chemical properties of PEI grafted HNTs (PEI-g-HNTs) were characterized by various methods. PEI-g-HNTs show lower cytotoxicity than PEI. PEI-g-HNTs are positively charged and can bind DNA tightly at designed N/P ratio from 5:1 to 40:1. PEI-g-HNTs/pDNA complexes show much higher transfection efficiency towards both 293T and HeLa cells compared with PEI/pDNA complexes at the equivalent N/P ratio. The transfection efficiencies of PEI-g-HNTs/pDNA complex towards HeLa cell can reach to 44.4% at N/P ratio of 20. PEI-g-HNTs/pDNA complexes possess a higher GFP protein expression than PEI/pDNA from simple western immunoblots. So, PEI-g-HNTs are potential gene vectors with good biocompatibility and high transfection efficiency, which have promising applications in cancer gene therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthetic biology: advancing the design of diverse genetic systems

PubMed Central

Wang, Yen-Hsiang; Wei, Kathy Y.; Smolke, Christina D.

2013-01-01

A main objective of synthetic biology is to make the process of designing genetically-encoded biological systems more systematic, predictable, robust, scalable, and efficient. The examples of genetic systems in the field vary widely in terms of operating hosts, compositional approaches, and network complexity, ranging from a simple genetic switch to search-and-destroy systems. While significant advances in synthesis capabilities support the potential for the implementation of pathway- and genome-scale programs, several design challenges currently restrict the scale of systems that can be reasonably designed and implemented. Synthetic biology offers much promise in developing systems to address challenges faced in manufacturing, the environment and sustainability, and health and medicine, but the realization of this potential is currently limited by the diversity of available parts and effective design frameworks. As researchers make progress in bridging this design gap, advances in the field hint at ever more diverse applications for biological systems. PMID:23413816

General solution for quantitative dark-field contrast imaging with grating interferometers

NASA Astrophysics Data System (ADS)

Strobl, M.

2014-11-01

Grating interferometer based imaging with X-rays and neutrons has proven to hold huge potential for applications in key research fields conveying biology and medicine as well as engineering and magnetism, respectively. The thereby amenable dark-field imaging modality implied the promise to access structural information beyond reach of direct spatial resolution. However, only here a yet missing approach is reported that finally allows exploiting this outstanding potential for non-destructive materials characterizations. It enables to obtain quantitative structural small angle scattering information combined with up to 3-dimensional spatial image resolution even at lab based x-ray or at neutron sources. The implied two orders of magnitude efficiency gain as compared to currently available techniques in this regime paves the way for unprecedented structural investigations of complex sample systems of interest for material science in a vast range of fields.

Occurrence of lignin degradation genotypes and phenotypes among prokaryotes.

PubMed

Tian, Jiang-Hao; Pourcher, Anne-Marie; Bouchez, Théodore; Gelhaye, Eric; Peu, Pascal

2014-12-01

A number of prokaryotes actively contribute to lignin degradation in nature and their activity could be of interest for many applications including the production of biogas/biofuel from lignocellulosic biomass and biopulping. This review compares the reliability and efficiency of the culture-dependent screening methods currently used for the isolation of ligninolytic prokaryotes. Isolated prokaryotes exhibiting lignin-degrading potential are presented according to their phylogenetic groups. With the development of bioinformatics, culture-independent techniques are emerging that allow larger-scale data mining for ligninolytic prokaryotic functions but today, these techniques still have some limits. In this work, two phylogenetic affiliations of isolated prokaryotes exhibiting ligninolytic potential and laccase-encoding prokaryotes were determined on the basis of 16S rDNA sequences, providing a comparative view of results obtained by the two types of screening techniques. The combination of laboratory culture and bioinformatics approaches is a promising way to explore lignin-degrading prokaryotes.

Electricity market design for the prosumer era

NASA Astrophysics Data System (ADS)

Parag, Yael; Sovacool, Benjamin K.

2016-04-01

Prosumers are agents that both consume and produce energy. With the growth in small and medium-sized agents using solar photovoltaic panels, smart meters, vehicle-to-grid electric automobiles, home batteries and other ‘smart’ devices, prosuming offers the potential for consumers and vehicle owners to re-evaluate their energy practices. As the number of prosumers increases, the electric utility sector of today is likely to undergo significant changes over the coming decades, offering possibilities for greening of the system, but also bringing many unknowns and risks that need to be identified and managed. To develop strategies for the future, policymakers and planners need knowledge of how prosumers could be integrated effectively and efficiently into competitive electricity markets. Here we identify and discuss three promising potential prosumer markets related to prosumer grid integration, peer-to-peer models and prosumer community groups. We also caution against optimism by laying out a series of caveats and complexities.

Hierarchical Cu2O foam/g-C3N4 photocathode for photoelectrochemical hydrogen production

NASA Astrophysics Data System (ADS)

Ma, Xinzhou; Zhang, Jingtao; Wang, Biao; Li, Qiuguo; Chu, Sheng

2018-01-01

Solar photoelectrochemical (PEC) hydrogen production is a promising way for solving energy and environment problems. Earth-abundant Cu2O is a potential light absorber for PEC hydrogen production. In this article, hierarchical porous Cu2O foams are prepared by thermal oxidation of the electrochemically deposited Cu foams. PEC performances of the Cu2O foams are systematically studied and discussed. Benefiting from their higher light harvesting and more efficient charge separation, the Cu2O foams demonstrate significantly enhanced photocurrents and photostability compared to their film counterparts. Moreover, by integrating g-C3N4, hierarchical Cu2O foam/g-C3N4 composites are prepared with further improved photocurrent and photostability, appearing to be potential photocathodes for solar PEC hydrogen production. This study may provide a new and useful insight for the development of Cu2O-based photocathodes for PEC hydrogen production.

Mycosporine-Like Amino Acids: Potential Health and Beauty Ingredients

PubMed Central

Chrapusta, Ewelina; Kaminski, Ariel; Duchnik, Kornelia; Bober, Beata; Adamski, Michal; Bialczyk, Jan

2017-01-01

Human skin is constantly exposed to damaging ultraviolet radiation (UVR), which induces a number of acute and chronic disorders. To reduce the risk of UV-induced skin injury, people apply an additional external protection in the form of cosmetic products containing sunscreens. Nowadays, because of the use of some chemical filters raises a lot of controversies, research focuses on exploring novel, fully safe and highly efficient natural UV-absorbing compounds that could be used as active ingredients in sun care products. A promising alternative is the application of multifunctional mycosporine-like amino acids (MAAs), which can effectively compete with commercially available filters. Here, we outline a complete characterization of these compounds and discuss their enormous biotechnological potential with special emphasis on their use as sunscreens, activators of cells proliferation, anti-cancer agents, anti-photoaging molecules, stimulators of skin renewal, and functional ingredients of UV-protective biomaterials. PMID:29065484

Fungal phytotoxins with potential herbicidal activity: chemical and biological characterization.

PubMed

Cimmino, Alessio; Masi, Marco; Evidente, Marco; Superchi, Stefano; Evidente, Antonio

2015-12-19

Covering: 2007 to 2015 Fungal phytotoxins are secondary metabolites playing an important role in the induction of disease symptoms interfering with host plant physiological processes. Although fungal pathogens represent a heavy constraint for agrarian production and for forest and environmental heritage, they can also represent an ecofriendly alternative to manage weeds. Indeed, the phytotoxins produced by weed pathogenic fungi are an efficient tool to design natural, safe bioherbicides. Their use could avoid that of synthetic pesticides causing resistance in the host plants and the long term impact of residues in agricultural products with a risk to human and animal health. The isolation and structural and biological characterization of phytotoxins produced by pathogenic fungi for weeds, including parasitic plants, are described. Structure activity relationships and mode of action studies for some phytotoxins are also reported to elucidate the herbicide potential of these promising fungal metabolites.

Stem cell and genetic therapies for the fetus.

PubMed

Roybal, Jessica L; Santore, Matthew T; Flake, Alan W

2010-02-01

Advances in prenatal diagnosis have led to the prenatal management of a variety of congenital diseases. Although prenatal stem cell and gene therapy await clinical application, they offer tremendous potential for the treatment of many genetic disorders. Normal developmental events in the fetus offer unique biologic advantages for the engraftment of hematopoietic stem cells and efficient gene transfer that are not present after birth. Although barriers to hematopoietic stem cell engraftment exist, progress has been made and preclinical studies are now underway for strategies based on prenatal tolerance induction to facilitate postnatal cellular transplantation. Similarly, in-utero gene therapy shows experimental promise for a host of diseases and proof-in-principle has been demonstrated in murine models, but ethical and safety issues still need to be addressed. Here we review the current status and future potential of prenatal cellular and genetic therapy. Copyright 2009 Elsevier Ltd. All rights reserved.

Wind turbine siting: A summary of the state of the art

NASA Technical Reports Server (NTRS)

Hiester, T. R.

1982-01-01

The process of siting large wind turbines may be divided into two broad steps: site selection, and site evaluation. Site selection is the process of locating windy sites where wind energy development shows promise of economic viability. Site evaluation is the process of determining in detail for a given site the economic potential of the site. The state of the art in the first aspect of siting, site selection is emphasized. Several techniques for assessing the wind resource were explored or developed in the Federal Wind Energy Program. Local topography and meteorology will determine which of the techniques should be used in locating potential sites. None of the techniques can do the job alone, none are foolproof, and all require considerable knowledge and experience to apply correctly. Therefore, efficient siting requires a strategy which is founded on broad based application of several techniques without relying solely on one narrow field of expertise.

Modeling Images of Natural 3D Surfaces: Overview and Potential Applications

NASA Technical Reports Server (NTRS)

Jalobeanu, Andre; Kuehnel, Frank; Stutz, John

2004-01-01

Generative models of natural images have long been used in computer vision. However, since they only describe the of 2D scenes, they fail to capture all the properties of the underlying 3D world. Even though such models are sufficient for many vision tasks a 3D scene model is when it comes to inferring a 3D object or its characteristics. In this paper, we present such a generative model, incorporating both a multiscale surface prior model for surface geometry and reflectance, and an image formation process model based on realistic rendering, the computation of the posterior model parameter densities, and on the critical aspects of the rendering. We also how to efficiently invert the model within a Bayesian framework. We present a few potential applications, such as asteroid modeling and Planetary topography recovery, illustrated by promising results on real images.

Chinese Herbal Medicines as Potential Agents for Alleviation of Heat Stress in Poultry

PubMed Central

MD Saadand, Salwani; Idrus, Zulkifli; Diao, Xiao Ping

2017-01-01

Heat stress negatively affects the productivity of chickens in commercial poultry farms in humid tropics. In this study, the concentrations and types of the antioxidant compounds of eight Chinese herbal medicines, which have previously demonstrated promising effects on suppressing heat stress as a mixture, were investigated using reversed-phase High Performance Liquid Chromatography, spectrophotometry, Liquid Chromatography Mass Spectrometry, and Gas-Liquid Chromatography. Our results provided the levels of phenolic compounds, total amounts of sugars, and total unsaturated fatty acids in the herbal extracts. Apart from the detection and quantification of the active ingredients of herbs that have the potential to mitigate heat stress in poultry, results of this study also provide useful data for developing an efficient and accurate formulation of the herbs' mixtures in order to induce positive effects against heat stress in in vivo studies. PMID:29209556

Towards a 'siliconeural computer': technological successes and challenges.

PubMed

Hughes, Mark A; Shipston, Mike J; Murray, Alan F

2015-07-28

Electronic signals govern the function of both nervous systems and computers, albeit in different ways. As such, hybridizing both systems to create an iono-electric brain-computer interface is a realistic goal; and one that promises exciting advances in both heterotic computing and neuroprosthetics capable of circumventing devastating neuropathology. 'Neural networks' were, in the 1980s, viewed naively as a potential panacea for all computational problems that did not fit well with conventional computing. The field bifurcated during the 1990s into a highly successful and much more realistic machine learning community and an equally pragmatic, biologically oriented 'neuromorphic computing' community. Algorithms found in nature that use the non-synchronous, spiking nature of neuronal signals have been found to be (i) implementable efficiently in silicon and (ii) computationally useful. As a result, interest has grown in techniques that could create mixed 'siliconeural' computers. Here, we discuss potential approaches and focus on one particular platform using parylene-patterned silicon dioxide.

Cavity-enhanced Raman microscopy of individual carbon nanotubes

PubMed Central

Hümmer, Thomas; Noe, Jonathan; Hofmann, Matthias S.; Hänsch, Theodor W.; Högele, Alexander; Hunger, David

2016-01-01

Raman spectroscopy reveals chemically specific information and provides label-free insight into the molecular world. However, the signals are intrinsically weak and call for enhancement techniques. Here, we demonstrate Purcell enhancement of Raman scattering in a tunable high-finesse microcavity, and utilize it for molecular diagnostics by combined Raman and absorption imaging. Studying individual single-wall carbon nanotubes, we identify crucial structural parameters such as nanotube radius, electronic structure and extinction cross-section. We observe a 320-times enhanced Raman scattering spectral density and an effective Purcell factor of 6.2, together with a collection efficiency of 60%. Potential for significantly higher enhancement, quantitative signals, inherent spectral filtering and absence of intrinsic background in cavity-vacuum stimulated Raman scattering render the technique a promising tool for molecular imaging. Furthermore, cavity-enhanced Raman transitions involving localized excitons could potentially be used for gaining quantum control over nanomechanical motion and open a route for molecular cavity optomechanics. PMID:27402165

Antimicrobial Peptides from Fruits and Their Potential Use as Biotechnological Tools—A Review and Outlook

PubMed Central

Meneguetti, Beatriz T.; Machado, Leandro dos Santos; Oshiro, Karen G. N.; Nogueira, Micaella L.; Carvalho, Cristiano M. E.; Franco, Octávio L.

2017-01-01

Bacterial resistance is a major threat to plant crops, animals and human health, and over the years this situation has increasingly spread worldwide. Due to their many bioactive compounds, plants are promising sources of antimicrobial compounds that can potentially be used in the treatment of infections caused by microorganisms. As well as stem, flowers and leaves, fruits have an efficient defense mechanism against pests and pathogens, besides presenting nutritional and functional properties due to their multifunctional molecules. Among such compounds, the antimicrobial peptides (AMPs) feature different antimicrobials that are capable of disrupting the microbial membrane and of acting in binding to intra-cytoplasmic targets of microorganisms. They are therefore capable of controlling or halting the growth of microorganisms. In summary, this review describes the major classes of AMPs found in fruits, their possible use as biotechnological tools and prospects for the pharmaceutical industry and agribusiness. PMID:28119671

Wood-Derived Ultrathin Carbon Nanofiber Aerogels.

PubMed

Li, Si-Cheng; Hu, Bi-Cheng; Ding, Yan-Wei; Liang, Hai-Wei; Li, Chao; Yu, Zi-You; Wu, Zhen-Yu; Chen, Wen-Shuai; Yu, Shu-Hong

2018-06-11

Carbon aerogels with 3D networks of interconnected nanometer-sized particles exhibit fascinating physical properties and show great application potential. Efficient and sustainable methods are required to produce high-performance carbon aerogels on a large scale to boost their practical applications. An economical and sustainable method is now developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels from the wood-based nanofibrillated cellulose (NFC) aerogels via a catalytic pyrolysis process, which guarantees high carbon residual and well maintenance of the nanofibrous morphology during thermal decomposition of the NFC aerogels. The wood-derived CNF aerogels exhibit excellent electrical conductivity, a large surface area, and potential as a binder-free electrode material for supercapacitors. The results suggest great promise in developing new families of carbon aerogels based on the controlled pyrolysis of economical and sustainable nanostructured precursors. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fundamental energy limits of SET-based Brownian NAND and half-adder circuits. Preliminary findings from a physical-information-theoretic methodology

NASA Astrophysics Data System (ADS)

Ercan, İlke; Suyabatmaz, Enes

2018-06-01

The saturation in the efficiency and performance scaling of conventional electronic technologies brings about the development of novel computational paradigms. Brownian circuits are among the promising alternatives that can exploit fluctuations to increase the efficiency of information processing in nanocomputing. A Brownian cellular automaton, where signals propagate randomly and are driven by local transition rules, can be made computationally universal by embedding arbitrary asynchronous circuits on it. One of the potential realizations of such circuits is via single electron tunneling (SET) devices since SET technology enable simulation of noise and fluctuations in a fashion similar to Brownian search. In this paper, we perform a physical-information-theoretic analysis on the efficiency limitations in a Brownian NAND and half-adder circuits implemented using SET technology. The method we employed here establishes a solid ground that enables studying computational and physical features of this emerging technology on an equal footing, and yield fundamental lower bounds that provide valuable insights into how far its efficiency can be improved in principle. In order to provide a basis for comparison, we also analyze a NAND gate and half-adder circuit implemented in complementary metal oxide semiconductor technology to show how the fundamental bound of the Brownian circuit compares against a conventional paradigm.

Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors

PubMed Central

Rennie, Anthony J. R.; Martins, Vitor L.; Smith, Rachel M.; Hall, Peter J.

2016-01-01

Electrochemical double layer capacitors (EDLCs) employing ionic liquid electrolytes are the subject of much research as they promise increased operating potentials, and hence energy densities, when compared with currently available devices. Herein we report on the influence of the particle size distribution of activated carbon material on the performance of ionic liquid based EDLCs. Mesoporous activated carbon was ball-milled for increasing durations and the resultant powders characterized physically (using laser diffraction, nitrogen sorption and SEM) and investigated electrochemically in the form of composite EDLC electrodes. A bi-modal particle size distribution was found for all materials demonstrating an increasing fraction of smaller particles with increased milling duration. In general, cell capacitance decreased with increased milling duration over a wide range of rates using CV and galvanostatic cycling. Reduced coulombic efficiency is observed at low rates (<25 mVs−1) and the efficiency decreases as the volume fraction of the smaller particles increases. Efficiency loss was attributed to side reactions, particularly electrolyte decomposition, arising from interactions with the smaller particles. The effect of reduced efficiency is confirmed by cycling for over 15,000 cycles, which has the important implication that diminished performance and reduced cycle life is caused by the presence of submicron-sized particles. PMID:26911531

Eph A10-modified pH-sensitive liposomes loaded with novel triphenylphosphine-docetaxel conjugate possess hierarchical targetability and sufficient antitumor effect both in vitro and in vivo.

PubMed

Zhang, Jiulong; Yang, Chunrong; Pan, Shuang; Shi, Menghao; Li, Jie; Hu, Haiyang; Qiao, Mingxi; Chen, Dawei; Zhao, Xiuli

2018-11-01

Mitochondrial-targeting therapy was considered to be a promising approach for the efficient treatment of cancer while positive charge induced nonspecific cytotoxicity severely limits its application. To overcome this drawback, a novel mitochondria targeted conjugate triphenylphosphine-docetaxel (TD) has been synthesized successfully and incorporated it into liposomes (EPSLP/TD), which possessed excellent pH-sensitive characteristic, EphA 10 mediated active targetability as well as mitochondria-targeting capability. EPSLP/TD was characterized to have a small particle size, high-encapsulation efficiency and excellent pH-sensitive characteristic. Compared with DTX-loaded liposomes (EPSLP/DTX), EPSLP/TD possessed higher cytotoxicity against MCF-7 cell line. Mitochondrial-targeting assay demonstrated mitochondria-targeting moiety triphenylphosphine (TPP) could efficiently deliver DTX to mitochondria. Western immunoblotting assay indicated that EPSLP/TD could efficiently deliver antitumor drug to mitochondria and induce cell apoptosis via mitochondria-mediated apoptosis pathway. In vivo antitumor study demonstrated EPSLP/TD owed excellent in vivo antitumor activity. Histological assay demonstrated EPSLP/TD showed strongly apoptosis inducing effect, anti-proliferation effect and anti-angiogenesis effect. This work investigated the potential of hierarchical targeting pH-sensitive liposomes is a suitable carrier to activate mitochondria-mediated apoptosis pathway for cancer therapy.

Structure relationship of cationic lipids on gene transfection mediated by cationic liposomes.

PubMed

Paecharoenchai, Orapan; Niyomtham, Nattisa; Apirakaramwong, Auayporn; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Yingyongnarongkul, Boon-ek; Opanasopit, Praneet

2012-12-01

The aim of this study was to investigate the transfection efficiency of cationic liposomes formulated with phosphatidylcholine (PC) and novel synthesized diethanolamine-based cationic lipids at a molar ratio of 5:1 in comparison with Lipofectamine™ 2000. Factors affecting transfection efficiency and cell viability, including the chemical structure of the cationic lipids, such as different amine head group (diamine and polyamine; and non-spermine and spermine) and acyl chain lengths (C14, C16, and C18) and the weight ratio of liposomes to DNA were evaluated on a human cervical carcinoma cell line (HeLa cells) using the pDNA encoding green fluorescent protein (pEGFP-C2). Characterizations of these lipoplexes in terms of size and charge measurement and agarose gel electrophoresis were performed. The results from this study revealed that almost no transfection was observed in the liposome formulations composed of cationic lipids with a non-spermine head group. In addition, the transfection efficiency of these cationic liposomes was in the following order: spermine-C14 > spermine-C16 > spermine-C18. The highest transfection efficiency was observed in the formulation of spermine-C14 liposomes at a weight ratio of 25; furthermore, this formulation was safe for use in vitro. In conclusion, cationic liposomes containing spermine head groups demonstrated promising potential as gene carriers.

Bacteriophage Mediates Efficient Gene Transfer in Combination with Conventional Transfection Reagents

PubMed Central

Donnelly, Amanda; Yata, Teerapong; Bentayebi, Kaoutar; Suwan, Keittisak; Hajitou, Amin

2015-01-01

The development of commercially available transfection reagents for gene transfer applications has revolutionized the field of molecular biology and scientific research. However, the challenge remains in ensuring that they are efficient, safe, reproducible and cost effective. Bacteriophage (phage)-based viral vectors have the potential to be utilized for general gene transfer applications within research and industry. Yet, they require adaptations in order to enable them to efficiently enter cells and overcome mammalian cellular barriers, as they infect bacteria only; furthermore, limited progress has been made at increasing their efficiency. The production of a novel hybrid nanocomplex system consisting of two different nanomaterial systems, phage vectors and conventional transfection reagents, could overcome these limitations. Here we demonstrate that the combination of cationic lipids, cationic polymers or calcium phosphate with M13 bacteriophage-derived vectors, engineered to carry a mammalian transgene cassette, resulted in increased cellular attachment, entry and improved transgene expression in human cells. Moreover, addition of a targeting ligand into the nanocomplex system, through genetic engineering of the phage capsid further increased gene expression and was effective in a stable cell line generation application. Overall, this new hybrid nanocomplex system (i) provides enhanced phage-mediated gene transfer; (ii) is applicable for laboratory transfection processes and (iii) shows promise within industry for large-scale gene transfer applications. PMID:26670247

Integration of CdSe/CdSexTe1−x Type-II Heterojunction Nanorods into Hierarchically Porous TiO2 Electrode for Efficient Solar Energy Conversion

PubMed Central

Lee, Sangheon; Flanagan, Joseph C.; Kang, Joonhyeon; Kim, Jinhyun; Shim, Moonsub; Park, Byungwoo

2015-01-01

Semiconductor sensitized solar cells, a promising candidate for next-generation photovoltaics, have seen notable progress using 0-D quantum dots as light harvesting materials. Integration of higher-dimensional nanostructures and their multi-composition variants into sensitized solar cells is, however, still not fully investigated despite their unique features potentially beneficial for improving performance. Herein, CdSe/CdSexTe1−x type-II heterojunction nanorods are utilized as novel light harvesters for sensitized solar cells for the first time. The CdSe/CdSexTe1−x heterojunction-nanorod sensitized solar cell exhibits ~33% improvement in the power conversion efficiency compared to its single-component counterpart, resulting from superior optoelectronic properties of the type-II heterostructure and 1-octanethiol ligands aiding facile electron extraction at the heterojunction nanorod-TiO2 interface. Additional ~32% enhancement in power conversion efficiency is achieved by introducing percolation channels of large pores in the mesoporous TiO2 electrode, which allow 1-D sensitizers to infiltrate the entire depth of electrode. These strategies combined together lead to 3.02% power conversion efficiency, which is one of the highest values among sensitized solar cells utilizing 1-D nanostructures as sensitizer materials. PMID:26638994

Electrode quenching control for highly efficient CsPbBr3 perovskite light-emitting diodes via surface plasmon resonance and enhanced hole injection by Au nanoparticles.

PubMed

Meng, Yan; Wu, Xiaoyan; Xiong, Ziyang; Lin, Chunyan; Xiong, Zuhong; Blount, Ethan; Chen, Ping

2018-04-27

Compared to organic-inorganic hybrid metal halide perovskites, all-inorganic cesium lead halides (e.g, CsPbBr 3 ) hold greater promise in being emissive materials for light-emitting diodes owing to their superior optoelectronic properties as well as their higher stabilities. However, there is still considerable potential for breakthroughs in the current efficiency of CsPbBr 3 perovskite light-emitting diodes (PeLEDs). Electrode quenching is one of the main problems limiting the current efficiency of PeLEDs when poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) is used as the hole injection layer. In this work, electrode quenching control was realized via incorporating Au NPs into PEDOT:PSS. As a result, the CsPbBr 3 PeLEDs realized an improvement in maximum luminescence ranging from ∼2348 to ∼7660 cd m -2 (∼226% enhancement) and current efficiency from 1.65 to 3.08 cd A -1 (∼86% enhancement). Such substantial enhancement of the electroluminescent performance can be attributed to effective electrode quenching control at the PEDOT:PSS/CsPbBr 3 perovskite interface via the combined effects of local surface plasma resonance coupling and enhanced hole transportation in the PEDOT:PSS layer by Au nanoparticles.

Dendrimers as Carriers for siRNA Delivery and Gene Silencing: A Review

PubMed Central

Huang, Weizhe; He, Ziying

2013-01-01

RNA interference (RNAi) was first literaturally reported in 1998 and has become rapidly a promising tool for therapeutic applications in gene therapy. In a typical RNAi process, small interfering RNAs (siRNA) are used to specifically downregulate the expression of the targeted gene, known as the term “gene silencing.” One key point for successful gene silencing is to employ a safe and efficient siRNA delivery system. In this context, dendrimers are emerging as potential nonviral vectors to deliver siRNA for RNAi purpose. Dendrimers have attracted intense interest since their emanating research in the 1980s and are extensively studied as efficient DNA delivery vectors in gene transfer applications, due to their unique features based on the well-defined and multivalent structures. Knowing that DNA and RNA possess a similar structure in terms of nucleic acid framework and the electronegative nature, one can also use the excellent DNA delivery properties of dendrimers to develop effective siRNA delivery systems. In this review, the development of dendrimer-based siRNA delivery vectors is summarized, focusing on the vector features (siRNA delivery efficiency, cytotoxicity, etc.) of different types of dendrimers and the related investigations on structure-activity relationship to promote safe and efficient siRNA delivery system. PMID:24288498

Electrode quenching control for highly efficient CsPbBr3 perovskite light-emitting diodes via surface plasmon resonance and enhanced hole injection by Au nanoparticles

NASA Astrophysics Data System (ADS)

Meng, Yan; Wu, Xiaoyan; Xiong, Ziyang; Lin, Chunyan; Xiong, Zuhong; Blount, Ethan; Chen, Ping

2018-04-01

Compared to organic-inorganic hybrid metal halide perovskites, all-inorganic cesium lead halides (e.g, CsPbBr3) hold greater promise in being emissive materials for light-emitting diodes owing to their superior optoelectronic properties as well as their higher stabilities. However, there is still considerable potential for breakthroughs in the current efficiency of CsPbBr3 perovskite light-emitting diodes (PeLEDs). Electrode quenching is one of the main problems limiting the current efficiency of PeLEDs when poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) is used as the hole injection layer. In this work, electrode quenching control was realized via incorporating Au NPs into PEDOT:PSS. As a result, the CsPbBr3 PeLEDs realized an improvement in maximum luminescence ranging from ˜2348 to ˜7660 cd m-2 (˜226% enhancement) and current efficiency from 1.65 to 3.08 cd A-1 (˜86% enhancement). Such substantial enhancement of the electroluminescent performance can be attributed to effective electrode quenching control at the PEDOT:PSS/CsPbBr3 perovskite interface via the combined effects of local surface plasma resonance coupling and enhanced hole transportation in the PEDOT:PSS layer by Au nanoparticles.

Integration of CdSe/CdSexTe1-x Type-II Heterojunction Nanorods into Hierarchically Porous TiO2 Electrode for Efficient Solar Energy Conversion.

PubMed

Lee, Sangheon; Flanagan, Joseph C; Kang, Joonhyeon; Kim, Jinhyun; Shim, Moonsub; Park, Byungwoo

2015-12-07

Semiconductor sensitized solar cells, a promising candidate for next-generation photovoltaics, have seen notable progress using 0-D quantum dots as light harvesting materials. Integration of higher-dimensional nanostructures and their multi-composition variants into sensitized solar cells is, however, still not fully investigated despite their unique features potentially beneficial for improving performance. Herein, CdSe/CdSe(x)Te(1-x) type-II heterojunction nanorods are utilized as novel light harvesters for sensitized solar cells for the first time. The CdSe/CdSe(x)Te(1-x) heterojunction-nanorod sensitized solar cell exhibits ~33% improvement in the power conversion efficiency compared to its single-component counterpart, resulting from superior optoelectronic properties of the type-II heterostructure and 1-octanethiol ligands aiding facile electron extraction at the heterojunction nanorod-TiO(2) interface. Additional ~31% enhancement in power conversion efficiency is achieved by introducing percolation channels of large pores in the mesoporous TiO(2) electrode, which allow 1-D sensitizers to infiltrate the entire depth of electrode. These strategies combined together lead to 3.02% power conversion efficiency, which is one of the highest values among sensitized solar cells utilizing 1-D nanostructures as sensitizer materials.

Bacteriophage Mediates Efficient Gene Transfer in Combination with Conventional Transfection Reagents.

PubMed

Donnelly, Amanda; Yata, Teerapong; Bentayebi, Kaoutar; Suwan, Keittisak; Hajitou, Amin

2015-12-08

The development of commercially available transfection reagents for gene transfer applications has revolutionized the field of molecular biology and scientific research. However, the challenge remains in ensuring that they are efficient, safe, reproducible and cost effective. Bacteriophage (phage)-based viral vectors have the potential to be utilized for general gene transfer applications within research and industry. Yet, they require adaptations in order to enable them to efficiently enter cells and overcome mammalian cellular barriers, as they infect bacteria only; furthermore, limited progress has been made at increasing their efficiency. The production of a novel hybrid nanocomplex system consisting of two different nanomaterial systems, phage vectors and conventional transfection reagents, could overcome these limitations. Here we demonstrate that the combination of cationic lipids, cationic polymers or calcium phosphate with M13 bacteriophage-derived vectors, engineered to carry a mammalian transgene cassette, resulted in increased cellular attachment, entry and improved transgene expression in human cells. Moreover, addition of a targeting ligand into the nanocomplex system, through genetic engineering of the phage capsid further increased gene expression and was effective in a stable cell line generation application. Overall, this new hybrid nanocomplex system (i) provides enhanced phage-mediated gene transfer; (ii) is applicable for laboratory transfection processes and (iii) shows promise within industry for large-scale gene transfer applications.

Modelling of fluoride removal via batch monopolar electrocoagulation process using aluminium electrodes

NASA Astrophysics Data System (ADS)

Amri, N.; Hashim, M. I.; Ismail, N.; Rohman, F. S.; Bashah, N. A. A.

2017-09-01

Electrocoagulation (EC) is a promising technology that extensively used to remove fluoride ions efficiently from industrial wastewater. However, it has received very little consideration and understanding on mechanism and factors that affecting the fluoride removal process. In order to determine the efficiency of fluoride removal in EC process, the effect of operating parameters such as voltage and electrolysis time were investigated in this study. A batch experiment with monopolar aluminium electrodes was conducted to identify the model of fluoride removal using empirical model equation. The EC process was investigated using several parameters which include voltage (3 - 12 V) and electrolysis time (0 - 60 minutes) at a constant initial fluoride concentration of 25 mg/L. The result shows that the fluoride removal efficiency increased steadily with increasing voltage and electrolysis time. The best fluoride removal efficiency was obtained with 94.8 % removal at 25 mg/L initial fluoride concentration, voltage of 12 V and 60 minutes electrolysis time. The results indicated that the rate constant, k and number of order, n decreased as the voltage increased. The rate of fluoride removal model was developed based on the empirical model equation using the correlation of k and n. Overall, the result showed that EC process can be considered as a potential alternative technology for fluoride removal in wastewater.

Site-Specific Genome Engineering in Human Pluripotent Stem Cells.

PubMed

Merkert, Sylvia; Martin, Ulrich

2016-06-24

The possibility to generate patient-specific induced pluripotent stem cells (iPSCs) offers an unprecedented potential of applications in clinical therapy and medical research. Human iPSCs and their differentiated derivatives are tools for diseases modelling, drug discovery, safety pharmacology, and toxicology. Moreover, they allow for the engineering of bioartificial tissue and are promising candidates for cellular therapies. For many of these applications, the ability to genetically modify pluripotent stem cells (PSCs) is indispensable, but efficient site-specific and safe technologies for genetic engineering of PSCs were developed only recently. By now, customized engineered nucleases provide excellent tools for targeted genome editing, opening new perspectives for biomedical research and cellular therapies.

In vitro generation of renal tubular epithelial cells from fibroblasts: implications for precision and regenerative medicine in nephrology.

PubMed

Wyatt, Christina M; Dubois, Nicole

2017-02-01

Prior efforts to generate renal epithelial cells in vitro have relied on pluripotent or bone marrow-derived mesenchymal stem cells. A recent publication in Nature Cell Biology describes the generation of induced tubular epithelial cells from fibroblasts, potentially offering a novel platform for personalized drug toxicity screening and in vitro disease modeling. This report serves as a promising proof of principle study and opens future research directions, including the optimization of the reprogramming process, efficient translation to adult human fibroblasts, and the generation of highly specific functional renal cell types. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

FT-NIR: A Tool for Process Monitoring and More.

PubMed

Martoccia, Domenico; Lutz, Holger; Cohen, Yvan; Jerphagnon, Thomas; Jenelten, Urban

2018-03-30

With ever-increasing pressure to optimize product quality, to reduce cost and to safely increase production output from existing assets, all combined with regular changes in terms of feedstock and operational targets, process monitoring with traditional instruments reaches its limits. One promising answer to these challenges is in-line, real time process analysis with spectroscopic instruments, and above all Fourier-Transform Near Infrared spectroscopy (FT-NIR). Its potential to afford decreased batch cycle times, higher yields, reduced rework and minimized batch variance is presented and application examples in the field of fine chemicals are given. We demonstrate that FT-NIR can be an efficient tool for improved process monitoring and optimization, effective process design and advanced process control.

High-dimensional atom localization via spontaneously generated coherence in a microwave-driven atomic system.

PubMed

Wang, Zhiping; Chen, Jinyu; Yu, Benli

2017-02-20

We investigate the two-dimensional (2D) and three-dimensional (3D) atom localization behaviors via spontaneously generated coherence in a microwave-driven four-level atomic system. Owing to the space-dependent atom-field interaction, it is found that the detecting probability and precision of 2D and 3D atom localization behaviors can be significantly improved via adjusting the system parameters, the phase, amplitude, and initial population distribution. Interestingly, the atom can be localized in volumes that are substantially smaller than a cubic optical wavelength. Our scheme opens a promising way to achieve high-precision and high-efficiency atom localization, which provides some potential applications in high-dimensional atom nanolithography.

Three-dimensional atom localization via electromagnetically induced transparency in a three-level atomic system.

PubMed

Wang, Zhiping; Cao, Dewei; Yu, Benli

2016-05-01

We present a new scheme for three-dimensional (3D) atom localization in a three-level atomic system via measuring the absorption of a weak probe field. Owing to the space-dependent atom-field interaction, the position probability distribution of the atom can be directly determined by measuring the probe absorption. It is found that, by properly varying the parameters of the system, the probability of finding the atom in 3D space can be almost 100%. Our scheme opens a promising way to achieve high-precision and high-efficiency 3D atom localization, which provides some potential applications in laser cooling or atom nano-lithography via atom localization.

Nanostructured lipid carriers as a potential vehicle for Carvedilol delivery: Application of factorial design approach.

PubMed

Patil, Ganesh B; Patil, Nandkishor D; Deshmukh, Prashant K; Patil, Pravin O; Bari, Sanjay B

2016-01-01

Present invention relates to design of nanostructured lipid carriers (NLC) to augment oral bioavailability of Carvedilol (CAR). In this attempt, formulations of CAR-NLCs were prepared with glyceryl-monostearate (GMS) as a lipid, poloxamer 188 as a surfactant and tween 80 as a co-surfactant using high pressure homogenizer by 2(3) factorial design approach. Formed CAR-NLCs were assessed for various performance parameters. Accelerated stability studies demonstrated negligible change in particle size and entrapment efficiency, after storage at specified time up to 3 months. The promising findings in this investigation suggest the practicability of these systems for enhancement of bioavailability of drugs like CAR.

Heat shock treatment improves Trametes versicolor laccase production.

PubMed

Wang, Feng; Guo, Chen; Wei, Tao; Zhang, Tian; Liu, Chun-Zhao

2012-09-01

An efficient heat shock strategy has been developed to improve laccase production in submerged Trametes versicolor cultures. The optimized heat shock strategy consists of subjecting T. versicolor mycelial pellets to three heat shock treatments at 45 °C for 45 min, starting at culture day 0, with a 24-h interval between treatments. Laccase production increased by more than 1.6-fold relative to the control in both flasks and a 5-L bioreactor because the expression of the laccase gene was enhanced by heat shock induction. The present work demonstrates that heat shock induction is a promising method because it both improves fungal laccase production and has a good potential in industrial application.

Stability control of a flexible maneuverable tethered space net robot

NASA Astrophysics Data System (ADS)

Zhang, Fan; Huang, Panfeng

2018-04-01

As a promising solution for active space debris capture and removal, a maneuverable Tethered Space Net Robot (TSNR) is proposed as an improved Space Tethered Net (TSN). In addition to the advantages inherit to the TSN, the TSNR's maneuverability expands the capture's potential. However, oscillations caused by the TSNR's flexibility and elasticity of make higher requests of the control scheme. Based on the dynamics model, a modified adaptive super-twisting sliding mode control scheme is proposed in this paper for TSNR stability control. The proposed continuous control force can effectively suppress oscillations. Theoretical verification and numerical simulations demonstrate that the desired trajectory can be tracked steadily and efficiently by employing the proposed control scheme.

Gene Therapy for Hemophilia and Duchenne Muscular Dystrophy in China.

PubMed

Liu, Xionghao; Liu, Mujun; Wu, Lingqian; Liang, Desheng

2018-02-01

Gene therapy is a new technology that provides potential for curing monogenic diseases caused by mutations in a single gene. Hemophilia and Duchenne muscular dystrophy (DMD) are ideal target diseases of gene therapy. Important advances have been made in clinical trials, including studies of adeno-associated virus vectors in hemophilia and antisense in DMD. However, issues regarding the high doses of viral vectors required and limited delivery efficiency of antisense oligonucleotides have not yet been fully addressed. As an alternative strategy to classic gene addition, genome editing based on programmable nucleases has also shown promise to correct mutations in situ. This review describes the recent progress made by Chinese researchers in gene therapy for hemophilia and DMD.

Effect of deep discharge on the electrochemical behavior of cobalt oxides and oxyhydroxides used as conductive additives in Ni-MH cells

NASA Astrophysics Data System (ADS)

Douin, Myriam; Guerlou-Demourgues, Liliane; Goubault, Lionel; Bernard, Patrick; Delmas, Claude

When used as conductive additive at the positive electrode of Ni-MH batteries, the Na 0.6CoO 2 phase is converted, during the first charge, by oxidation, in a γ-hydrated cobalt oxyhydroxide, which exhibits promising performances. The behavior of these phases was studied in specific deep discharge or low potential storage conditions, through electrochemical short-circuit experiments. The evolution of the electrodes during the cycling was followed by X-ray diffraction and SEM analysis. These novel additives appear to be more efficient in these extreme conditions than the CoO or Co(OH) 2 additives, commonly used in industrial devices.

Paracyclophane functionalized with Sc and Li for hydrogen storage

NASA Astrophysics Data System (ADS)

Sathe, Rohit Y.; Dhilip Kumar, T. J.

2018-01-01

Li and Sc metals functionalized on the delocalized π -electrons of benzene rings in [2,2]paracyclophane structure are studied for hydrogen storage efficiency by using the M06 DFT functional with 6-311G(d,p) basis set. It is found that Sc and Li functionalized [2,2]paracyclophane complexes can hold up to 10 H2 molecules and 8 H2 molecules by Kubas-Niu-Jena interaction and charge polarization mechanism with hydrogen weight percentage of 11.4 and 13.5, respectively. Molecular dynamics simulation at various temperatures showed appreciable thermal stability while the chemical potential calculation at room temperature reveals that Sc functionalized [2,2]paracyclophane system will be a promising hydrogen storage material.

Magnetic Phase Transition in Spark-Produced Ternary LaFeSi Nanoalloys.

PubMed

Feng, Jicheng; Geutjens, Ruben; Thang, Nguyen V; Li, Junjie; Guo, Xiaoai; Kéri, Albert; Basak, Shibabrata; Galbács, Gábor; Biskos, George; Nirschl, Hermann; Zandbergen, Henny W; Brück, Ekkes; Schmidt-Ott, Andreas

2018-02-21

Using the magnetocaloric effect in nanoparticles holds great potential for efficient refrigeration and energy conversion. The most promising candidate materials for tailoring the Curie temperature to room temperature are rare-earth-based magnetic nanoalloys. However, only few high-nuclearity lanthanide/transition-metal nanoalloys have been produced so far. Here we report, for the first time, the observation of magnetic response in spark-produced LaFeSi nanoalloys. The results suggest that these nanoalloys can be used to exploit the magnetocaloric effect near room temperature; such a finding can lead to the creation of unique multicomponent materials for energy conversion, thus helping toward the realization of a sustainable energy economy.

Online analysis and process control in recombinant protein production (review).

PubMed

Palmer, Shane M; Kunji, Edmund R S

2012-01-01

Online analysis and control is essential for efficient and reproducible bioprocesses. A key factor in real-time control is the ability to measure critical variables rapidly. Online in situ measurements are the preferred option and minimize the potential loss of sterility. The challenge is to provide sensors with a good lifespan that withstand harsh bioprocess conditions, remain stable for the duration of a process without the need for recalibration, and offer a suitable working range. In recent decades, many new techniques that promise to extend the possibilities of analysis and control, not only by providing new parameters for analysis, but also through the improvement of accepted, well practiced, measurements have arisen.

An isopropanol-assisted fabrication strategy of pinhole-free perovskite films in air for efficient and stable planar perovskite solar cells

NASA Astrophysics Data System (ADS)

Ren, Ziqiu; Zhu, Menghua; Li, Xin; Dong, Cunku

2017-09-01

As a promising photovoltaic device, perovskite solar cells have attracted numerous attention in recent years, where forming a compact and pinhole-free perovskite film in air is of great importance. Herein, we evaluate highly efficient and air stable planar perovskite solar cells in air (relative humidity over 50%) with the modified two-step sequential deposition method by adjusting the CH3NH3I (MAI) concentrations and regulating the crystallization process of the perovskite film. The optimum MAI concentration is 60 mg mL-1 in isopropanol. With a planar structure of FTO/TiO2/MAPbI3/spiro-OMeTAD/Au, the efficient devices composed of compact and pinhole-free perovskite films are constructed in air, achieving a high efficiency of up to 15.10% and maintaining over 80% after 20 days storing without any encapsulation in air. With a facile fabrication process and high photovoltaic performance, this work represents a promising method for fabricating low-cost, highly efficient and stable photovoltaic device.

Utility of adsorbents in the purification of drinking water: a review of characterization, efficiency and safety evaluation of various adsorbents.

PubMed

Dubey, Shashi Prabha; Gopal, Krishna; Bersillon, J L

2009-05-01

Clean drinking water is one of the implicit requisites fora healthy human population. However the growing industrialization and extensive use of chemicals for various concerns, has increased the burden of unwanted pollutants in the drinking water of developing countries like India. The entry of potentially hazardous substances into the biota has been magnifying day by day. In the absence of a possible stoppage of these, otherwise, useful chemicals, the only way to maintain safer water bodies is to develop efficient purifying technologies. One such immensely beneficial procedure that has been in use is that of purification of water using 'adsorbents'. Indigenous minerals and natural plants products have potential for removing many pollutants viz. fluoride, arsenic, nitrate, heavy metals, pesticides as well as trihalomethanes. Adsorbents which are derived from carbon, alumina, zeolite, clay minerals, iron ores, industrial by products, and natural products viz. parts of the plants, herbs and algal biomass offer promising potential of removal. In the recent years attention has been paid to develop process involving screening/pretreatment/activation/impregnation using alkalies, acids, alum, lime, manganese dioxide, ferric chloride and other chemicals which are found to enhance their adsorbing efficiency. Chemical characterization of these adsorbents recapitulates the mechanism of the process. It is imperative to observe that capacities of the adsorbents may vary depending on the characteristics, chemical modifications and concentration of the individual adsorbent. Removal kinetics is found to be based on the experimental conditions viz. pH, concentration of the adsorbate, quantity of the adsorbent and temperature. It is suggested that isotherm model is suitable tool to assess the adsorption capacities in batch and column modes. Safety evaluation and risk assessment of the process/products may be useful to provide guidelines for its sustainable disposal.

Efficient MRI labeling of endothelial progenitor cells: design of thiolated surface stabilized superparamagnetic iron oxide nanoparticles.

PubMed

Shahnaz, Gul; Kremser, Christian; Reinisch, Andreas; Vetter, Anja; Laffleur, Flavia; Rahmat, Deni; Iqbal, Javed; Dünnhaupt, Sarah; Salvenmoser, Willi; Tessadri, Richard; Griesser, Ulrich; Bernkop-Schnürch, Andreas

2013-11-01

The aim of this study was to design thiolated surface stabilized superparamagnetic iron oxide nanoparticles (TSS-SPIONs) for efficient internalization with high MRI sensitivity. TSS-SPIONs were developed by chelation between thiolated chitosan-thioglycolic acid (chitosan-TGA) hydrogel and iron ions (Fe(2+)/Fe(3+)). Likely, unmodified chitosan hydrogel SPIONs (UC-SPIONs) and uncoated SPIONs were used as control. Moreover, TSS-SPIONs were investigated regarding to their iron core size, hydrodynamic diameter, zeta potential, iron contents, molar relaxivities (r1 and r2), and cellular internalization. TSS-SPIONs demonstrated an iron oxide core diameter (crystallite size by XRD) of 3.1 ± 0.02 nm, a hydrodynamic diameter of 94 ± 20 nm, a zeta potential of +21 ± 5 mV, and an iron content of 3.6 ± 0.9 mg/mL. In addition, internalization of TSS-SPIONs into human endothelial progenitor cells (EPC) from umbilical cord blood was more than threefold and 17-fold higher in contrast to UC-SPIONs and SPIONs, respectively. With twofold lower incubation iron concentration of TSS-SPIONs, more than threefold higher internalization was achieved as compared to Resovist®. Also, cell viability of more than 90% was observed in the presence of TSS-SPIONs after 24h. The molar MR relaxivities (r2) value at 1.5 T was threefold higher than that of Resovist® and demonstrated that TSS-SPIONs have the potential as very effective T2 contrast-enhancement agent. According to these findings, TSS-SPIONs with efficient internalization, lower cytotoxicity, and high MRI sensitivity seem to be promising for cell tracking. Copyright © 2013 Elsevier B.V. All rights reserved.

Topical phenytoin nanostructured lipid carriers: design and development.

PubMed

Motawea, Amira; Borg, Thanaa; Abd El-Gawad, Abd El-Gawad H

2018-01-01

Phenytoin (PHT) is an antiepileptic drug that was reported to exhibit high wound healing activity. Nevertheless, its limited solubility, bioavailability, and inefficient distribution during topical administration limit its use. Therefore, this study aims to develop, characterize nanostructured lipid carriers (NLCs), and evaluate their potential in topical delivery of PHT to improve the drug entrapment efficiency and sustained release. The NLCs were prepared by hot homogenization followed by ultra sonication method using 2 3 factorial design. NLC formulations were characterized regarding their particle size (PS), zeta potential (ZP), entrapment efficiency percent (%EE), surface morphology, physicochemical stability, and in vitro release studies. The optimized NLC (F7) was further incorporated in 1%w/v carbopol gel and then characterized for appearance, pH, viscosity, stability, and in vitro drug release. The prepared NLCs were spherical in shape and possessed an average PS of 121.4-258.2 nm, ZP of (-15.4)-(-32.2) mV, and 55.24-88.80 %EE. Solid-state characterization revealed that the drug is dispersed in an amorphous state with hydrogen bond interaction between the drug and the NLC components. NLC formulations were found to be stable at 25 °C for six months. The stored F7-hydrogel showed insignificant changes in viscosity and drug content (p>.05) up to six months at 25 °C that pave a way for industrial fabrication of efficient PHT products. In vitro release studies showed a sustained release from NLC up to 48 h at pH 7.4 following non-Fickian Higuchi kinetics model. These promising findings encourage the potential use of phenytoin loaded lipid nanoparticles for future topical application.

Salinity tolerance ecophysiology of Equisetum giganteum in South America: a study of 11 sites providing a natural gradient of salinity stress

PubMed Central

Husby, Chad E.; Delatorre, José; Oreste, Vittorio; Oberbauer, Steven F.; Palow, Danielle T.; Novara, Lázaro; Grau, Alfredo

2011-01-01

Background and aims The basic set of adaptations necessary for salinity tolerance in vascular plants remains unknown. Although much has been published on salinity stress, almost all studies deal with spermatophytes. Studies of salinity tolerance in pteridophytes are relatively rare but hold promise for revealing the fundamental adaptations that all salt-tolerant vascular plants may share. The most basal pteridophytes to exhibit salinity tolerance are members of the genus Equisetum, including the giant horsetail, Equisetum giganteum, the only pteridophyte to occur in salinity-affected regions of the Atacama Desert valleys of northern Chile. Here it can constitute a significant vegetation component, forming dense stands of shoots >4 m high. Methodology Physiological parameters (stomatal conductances; efficiency of photosystem II; sap osmotic potential) were measured in E. giganteum populations in northern Chile across a range of groundwater salinities at 11 sites. In addition, Na, K, electrical conductivity and total plant water potential were measured in the plants and groundwater from each site. Principal results Equisetum giganteum exhibits similar stomatal conductances and photochemical efficiencies of photosystem II across a wide range of groundwater salinities. It lowers cell sap osmotic potential with increasing salinity and produces positive root pressure, as evidenced by guttation, at the full range of salinities experienced in the Atacama Desert. Equisetum giganteum maintains low Na concentrations in its xylem fluid and cell sap when soil water Na is high. It also maintains high K/Na ratios in xylem fluid and cell sap when soil water has low K/Na ratios. Conclusions Equisetum giganteum is well adapted to salinity stress. Efficient K uptake and Na exclusion are important adaptations and closely similar to those of the facultative halophyte fern Acrostichum aureum. PMID:22476492

Combining and Comparing Coalescent, Distance and Character-Based Approaches for Barcoding Microalgaes: A Test with Chlorella-Like Species (Chlorophyta).

PubMed

Zou, Shanmei; Fei, Cong; Song, Jiameng; Bao, Yachao; He, Meilin; Wang, Changhai

2016-01-01

Several different barcoding methods of distinguishing species have been advanced, but which method is the best is still controversial. Chlorella is becoming particularly promising in the development of second-generation biofuels. However, the taxonomy of Chlorella-like organisms is easily confused. Here we report a comprehensive barcoding analysis of Chlorella-like species from Chlorella, Chloroidium, Dictyosphaerium and Actinastrum based on rbcL, ITS, tufA and 16S sequences to test the efficiency of traditional barcoding, GMYC, ABGD, PTP, P ID and character-based barcoding methods. First of all, the barcoding results gave new insights into the taxonomic assessment of Chlorella-like organisms studied, including the clear species discrimination and resolution of potentially cryptic species complexes in C. sorokiniana, D. ehrenbergianum and C. Vulgaris. The tufA proved to be the most efficient barcoding locus, which thus could be as potential "specific barcode" for Chlorella-like species. The 16S failed in discriminating most closely related species. The resolution of GMYC, PTP, P ID, ABGD and character-based barcoding methods were variable among rbcL, ITS and tufA genes. The best resolution for species differentiation appeared in tufA analysis where GMYC, PTP, ABGD and character-based approaches produced consistent groups while the PTP method over-split the taxa. The character analysis of rbcL, ITS and tufA sequences could clearly distinguish all taxonomic groups respectively, including the potentially cryptic lineages, with many character attributes. Thus, the character-based barcoding provides an attractive complement to coalescent and distance-based barcoding. Our study represents the test that proves the efficiency of multiple DNA barcoding in species discrimination of microalgaes.

Combining and Comparing Coalescent, Distance and Character-Based Approaches for Barcoding Microalgaes: A Test with Chlorella-Like Species (Chlorophyta)

PubMed Central

Zou, Shanmei; Fei, Cong; Song, Jiameng; Bao, Yachao; He, Meilin; Wang, Changhai

2016-01-01

Several different barcoding methods of distinguishing species have been advanced, but which method is the best is still controversial. Chlorella is becoming particularly promising in the development of second-generation biofuels. However, the taxonomy of Chlorella–like organisms is easily confused. Here we report a comprehensive barcoding analysis of Chlorella-like species from Chlorella, Chloroidium, Dictyosphaerium and Actinastrum based on rbcL, ITS, tufA and 16S sequences to test the efficiency of traditional barcoding, GMYC, ABGD, PTP, P ID and character-based barcoding methods. First of all, the barcoding results gave new insights into the taxonomic assessment of Chlorella-like organisms studied, including the clear species discrimination and resolution of potentially cryptic species complexes in C. sorokiniana, D. ehrenbergianum and C. Vulgaris. The tufA proved to be the most efficient barcoding locus, which thus could be as potential “specific barcode” for Chlorella-like species. The 16S failed in discriminating most closely related species. The resolution of GMYC, PTP, P ID, ABGD and character-based barcoding methods were variable among rbcL, ITS and tufA genes. The best resolution for species differentiation appeared in tufA analysis where GMYC, PTP, ABGD and character-based approaches produced consistent groups while the PTP method over-split the taxa. The character analysis of rbcL, ITS and tufA sequences could clearly distinguish all taxonomic groups respectively, including the potentially cryptic lineages, with many character attributes. Thus, the character-based barcoding provides an attractive complement to coalescent and distance-based barcoding. Our study represents the test that proves the efficiency of multiple DNA barcoding in species discrimination of microalgaes. PMID:27092945

DNA vaccination elicits protective immune responses against pandemic and classic swine influenza viruses in pigs.

PubMed

Gorres, J Patrick; Lager, Kelly M; Kong, Wing-Pui; Royals, Michael; Todd, John-Paul; Vincent, Amy L; Wei, Chih-Jen; Loving, Crystal L; Zanella, Eraldo L; Janke, Bruce; Kehrli, Marcus E; Nabel, Gary J; Rao, Srinivas S

2011-11-01

Swine influenza is a highly contagious viral infection in pigs that significantly impacts the pork industry due to weight loss and secondary infections. There is also the potential of a significant threat to public health, as was seen in 2009 when the pandemic H1N1 influenza virus strain emerged from reassortment events among avian, swine, and human influenza viruses within pigs. As classic and pandemic H1N1 strains now circulate in swine, an effective vaccine may be the best strategy to protect the pork industry and public health. Current inactivated-virus vaccines available for swine influenza protect only against viral strains closely related to the vaccine strain, and egg-based production of these vaccines is insufficient to respond to large outbreaks. DNA vaccines are a promising alternative since they can potentially induce broad-based protection with more efficient production methods. In this study we evaluated the potentials of monovalent and trivalent DNA vaccine constructs to (i) elicit both humoral and gamma interferon (IFN-γ) responses and (ii) protect pigs against viral shedding and lung disease after challenge with pandemic H1N1 or classic swine H1N1 influenza virus. We also compared the efficiency of a needle-free vaccine delivery method to that of a conventional needle/syringe injection. We report that DNA vaccination elicits robust serum antibody and cellular responses after three immunizations and confers significant protection against influenza virus challenge. Needle-free delivery elicited improved antibody responses with the same efficiency as conventional injection and should be considered for development as a practical alternative for vaccine administration.

Ecofriendly and Nonvacuum Electrostatic Spray-Assisted Vapor Deposition of Cu(In,Ga)(S,Se)2 Thin Film Solar Cells.

PubMed

Hossain, Md Anower; Wang, Mingqing; Choy, Kwang-Leong

2015-10-14

Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, nonvacuum, and cost-effective electrostatic spray-assisted vapor deposition (ESAVD) method. The generation of a fine aerosol of precursor solution, and their controlled deposition onto a molybdenum substrate, results in adherent, dense, and uniform Cu(In,Ga)S2 (CIGS) films. This is an essential tool to keep the interfacial area of thin film solar cells to a minimum value for efficient charge separation as it helps to achieve the desired surface smoothness uniformity for subsequent cadmium sulfide and window layer deposition. This nonvacuum aerosol based approach for making the CIGSSe film uses environmentally benign precursor solution, and it is cheaper for producing solar cells than that of the vacuum-based thin film solar technology. An optimized CIGSSe thin film solar cell with a device configuration of molybdenum-coated soda-lime glass substrate/CIGSSe/CdS/i-ZnO/AZO shows the photovoltaic (j-V) characteristics of Voc=0.518 V, jsc=28.79 mA cm(-2), fill factor=64.02%, and a promising power conversion efficiency of η=9.55% under simulated AM 1.5 100 mW cm(-2) illuminations, without the use of an antireflection layer. This demonstrates the potential of ESAVD deposition as a promising alternative approach for making thin film CIGSSe solar cells at a lower cost.

Reprogramming of Pancreatic Exocrine Cells AR42J Into Insulin-producing Cells Using mRNAs for Pdx1, Ngn3, and MafA Transcription Factors.

PubMed

Koblas, Tomas; Leontovyc, Ivan; Loukotova, Sarka; Kosinova, Lucie; Saudek, Frantisek

2016-05-17

Direct reprogramming of pancreatic nonendocrine cells into insulin-producing β-cells represents a promising approach for the treatment of insulin-dependent diabetes. However, its clinical application is limited by the potential for insertional mutagenesis associated with the viral vectors currently used for cell reprogramming. With the aim of developing a nonintegrative reprogramming strategy for derivation of insulin-producing cells, here, we evaluated a new approach utilizing synthetic messenger RNAs encoding reprogramming transcription factors. Administration of synthetic mRNAs encoding three key transcription regulators of β-cell differentiation-Pdx1, Neurogenin3, and MafA-efficiently reprogrammed the pancreatic exocrine cells into insulin-producing cells. In addition to the insulin genes expression, the synthetic mRNAs also induced the expressions of genes important for proper pancreatic β-cell function, including Sur1, Kir6.2, Pcsk1, and Pcsk2. Pretreating cells with the chromatin-modifying agent 5-Aza-2'-deoxycytidine further enhanced reprogramming efficiency, increasing the proportion of insulin-producing cells from 3.5 ± 0.9 to 14.3 ± 1.9% (n = 4). Moreover, 5-Aza-2'-deoxycytidine pretreatment enabled the reprogrammed cells to respond to glucose challenge with increased insulin secretion. In conclusion, our results support that the reprogramming of pancreatic exocrine cells into insulin-producing cells, induced by synthetic mRNAs encoding pancreatic transcription factors, represents a promising approach for cell-based diabetes therapy.

Cationic solid-lipid nanoparticles are as efficient as electroporation in DNA vaccination against visceral leishmaniasis in mice.

PubMed

Saljoughian, N; Zahedifard, F; Doroud, D; Doustdari, F; Vasei, M; Papadopoulou, B; Rafati, S

2013-12-01

The use of an appropriate delivery system has recently emerged as a promising approach for the development of effective vaccination against visceral leishmaniasis (VL). Here, we compare two vaccine delivery systems, namely electroporation and cationic solid-lipid nanoparticle (cSLN) formulation, to administer a DNA vaccine harbouring the L. donovani A2 antigen along with L. infantum cysteine proteinases [CPA and CPB without its unusual C-terminal extension (CPB(-CTE) )] and evaluate their potential against L. infantum challenge. Prime-boost administration of the pcDNA-A2-CPA-CPB(-CTE) delivered by either electroporation or cSLN formulation protects BALB/c mice against L. infantum challenge and that protective immunity is associated with high levels of IFN-γ and lower levels of IL-10 production, leading to a strong Th1 immune response. At all time points, the ratio of IFN-γ: IL-10 induced upon restimulation with rA2-rCPA-rCPB and F/T antigens was significantly higher in vaccinated animals. Moreover, Th2-efficient protection was elicited through a high humoral immune response. Nitric oxide production, parasite burden and histopathological analysis were also in concordance with other findings. Overall, these data indicate that similar to the electroporation delivery system, cSLNs as a nanoscale vehicle of Leishmania antigens could improve immune response, hence indicating the promise of these strategies against visceral leishmaniasis. © 2013 John Wiley & Sons Ltd.

[Testicular tissue vitrification: evolution or revolution?].

PubMed

Wyns, C; Abu-Ghannam, G; Poels, J

2013-09-01

Preservation of reproductive health is a major concern for patient long-term quality of life. While sperm freezing has proven to be effective to preserve fertility after puberty, cryopreservation of immature testicular tissue (ITT) is emerging as a promising approach for fertility preservation in young boys. Slow-freezing (SF) is the conventional method used to preserve ITT and has resulted in the birth of mice offspring. In humans, methods to preserve ITT are still at the research stage. Controlled SF using dimethyl sulfoxide showed preservation of proliferative spermatogonia after thawing in a xenotransplantation model used to evaluate the efficiency of freezing and thawing procedures. However, spermatogonial recovery was low and normal differentiation could not be achieved. Both freezing/thawing and the environment of the xenotransplantation model may be implicated. Indeed, with SF, ice crystal formation could damage tissue and cells. For this reason, vitrification, leading to solidification of a liquid without crystallization, may be a promising alternative. ITT vitrification has been investigated in different species and shown spermatogonial survival and differentiation to the round or elongated spermatids stage. Offspring were also recently obtained after vitrification and allotransplantation in avians, confirming the potential of vitrification for fertility preservation. In humans, vitrification appears to be as efficient as SF in terms of spermatogonial survival and initiation of differentiation after xenotransplantation. However, before validation of such fertility preservation methods, completion of normal spermatogenesis and the fertilization capacity of sperm retrieved from cryopreserved and transplanted tissue should be fully investigated. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Biology and biotechnology of Trichoderma.

PubMed

Schuster, André; Schmoll, Monika

2010-07-01

Fungi of the genus Trichoderma are soilborne, green-spored ascomycetes that can be found all over the world. They have been studied with respect to various characteristics and applications and are known as successful colonizers of their habitats, efficiently fighting their competitors. Once established, they launch their potent degradative machinery for decomposition of the often heterogeneous substrate at hand. Therefore, distribution and phylogeny, defense mechanisms, beneficial as well as deleterious interaction with hosts, enzyme production and secretion, sexual development, and response to environmental conditions such as nutrients and light have been studied in great detail with many species of this genus, thus rendering Trichoderma one of the best studied fungi with the genome of three species currently available. Efficient biocontrol strains of the genus are being developed as promising biological fungicides, and their weaponry for this function also includes secondary metabolites with potential applications as novel antibiotics. The cellulases produced by Trichoderma reesei, the biotechnological workhorse of the genus, are important industrial products, especially with respect to production of second generation biofuels from cellulosic waste. Genetic engineering not only led to significant improvements in industrial processes but also to intriguing insights into the biology of these fungi and is now complemented by the availability of a sexual cycle in T. reesei/Hypocrea jecorina, which significantly facilitates both industrial and basic research. This review aims to give a broad overview on the qualities and versatility of the best studied Trichoderma species and to highlight intriguing findings as well as promising applications.

Biology and biotechnology of Trichoderma

PubMed Central

Schuster, André

2010-01-01

Fungi of the genus Trichoderma are soilborne, green-spored ascomycetes that can be found all over the world. They have been studied with respect to various characteristics and applications and are known as successful colonizers of their habitats, efficiently fighting their competitors. Once established, they launch their potent degradative machinery for decomposition of the often heterogeneous substrate at hand. Therefore, distribution and phylogeny, defense mechanisms, beneficial as well as deleterious interaction with hosts, enzyme production and secretion, sexual development, and response to environmental conditions such as nutrients and light have been studied in great detail with many species of this genus, thus rendering Trichoderma one of the best studied fungi with the genome of three species currently available. Efficient biocontrol strains of the genus are being developed as promising biological fungicides, and their weaponry for this function also includes secondary metabolites with potential applications as novel antibiotics. The cellulases produced by Trichoderma reesei, the biotechnological workhorse of the genus, are important industrial products, especially with respect to production of second generation biofuels from cellulosic waste. Genetic engineering not only led to significant improvements in industrial processes but also to intriguing insights into the biology of these fungi and is now complemented by the availability of a sexual cycle in T. reesei/Hypocrea jecorina, which significantly facilitates both industrial and basic research. This review aims to give a broad overview on the qualities and versatility of the best studied Trichoderma species and to highlight intriguing findings as well as promising applications. PMID:20461510

Oncolytic Adenovirus Complexes Coated with Lipids and Calcium Phosphate for Cancer Gene Therapy.

PubMed

Chen, Jianhua; Gao, Pei; Yuan, Sujing; Li, Rongxin; Ni, Aimin; Chu, Liang; Ding, Li; Sun, Ying; Liu, Xin-Yuan; Duan, Yourong

2016-12-27

Oncolytic adenovirus (Onco Ad ) is a promising therapeutic agent for treating cancer. However, the therapeutic potential of Onco Ad is hindered by hepatic sequestration and the host immune response in vivo. Here, we constructed a PEG/Lipids/calcium phosphate (CaP)-Onco Ad (PLC-Onco Ad ) delivery system for ZD55-IL-24, an oncolytic adenovirus that carries the IL-24 gene. The negatively charged PLC-ZD55-IL-24 were disperse and resisted serum-induced aggregation. Compared to naked ZD55-IL-24, the systemic administration of PLC-ZD55-IL-24 in BALB/c mice resulted in reduced liver sequestration and systemic toxicity and evaded the innate immune response. In addition, masking the surface of Onco Ad protected it from neutralization by pre-existing neutralizing antibody. PLC-Onco Ad achieved efficient targeted delivery in Huh-7-bearing nude mice, and intravenous administration of a high dose of PLC-ZD55-IL-24 increased therapeutic efficacy without inducing toxicity. The developed PLC-Onco Ad delivery system represents a promising improvement for oncolytic adenovirus-based cancer gene therapy in vivo.

High-performance single CdS nanowire (nanobelt) Schottky junction solar cells with Au/graphene Schottky electrodes.

PubMed

Ye, Yu; Dai, Yu; Dai, Lun; Shi, Zujin; Liu, Nan; Wang, Fei; Fu, Lei; Peng, Ruomin; Wen, Xiaonan; Chen, Zhijian; Liu, Zhongfan; Qin, Guogang

2010-12-01

High-performance single CdS nanowire (NW) as well as nanobelt (NB) Schottky junction solar cells were fabricated. Au (5 nm)/graphene combined layers were used as the Schottky contact electrodes to the NWs (NBs). Typical as-fabricated NW solar cell shows excellent photovoltaic behavior with an open circuit voltage of ∼0.15 V, a short circuit current of ∼275.0 pA, and an energy conversion efficiency of up to ∼1.65%. The physical mechanism of the combined Schottky electrode was discussed. We attribute the prominent capability of the devices to the high-performance Schottky combined electrode, which has the merits of low series resistance, high transparency, and good Schottky contact to the CdS NW (NB). Besides, a promising site-controllable patterned graphene transfer method, which has the advantages of economizing graphene material and free from additional etching process, was demonstrated in this work. Our results suggest that semiconductor NWs (NBs) are promising materials for novel solar cells, which have potential application in integrated nano-optoelectronic systems.