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.

Selection of appropriate isolation method based on morphology of blastocyst for efficient derivation of buffalo embryonic stem cells.

PubMed

Kumar, R; Ahlawat, S P S; Sharma, M; Verma, O P; Sai Kumar, G; Taru Sharma, G

2014-03-01

The efficiency of embryonic stem cell (ESC) derivation from all species except for rodents and primates is very low. There are however, multiple interests in obtaining pluripotent cells from these animals with main expectations in the fields of transgenesis, cloning, regenerative medicine and tissue engineering. Researches are being carried out in laboratories throughout the world to increase the efficiency of ESC isolation for their downstream applications. Thus, the present study was undertaken to study the effect of different isolation methods based on the morphology of blastocyst for efficient derivation of buffalo ESCs. Embryos were produced in vitro through the procedures of maturation, fertilization and culture. Hatched blastocysts or isolated inner cell masses (ICMs) were seeded on mitomycin-C inactivated buffalo fetal fibroblast monolayer for the development of ESC colonies. The ESCs were analyzed for alkaline phosphatase activity, expression of pluripotency markers and karyotypic stability. Primary ESC colonies were obtained after 2-5 days of seeding hatched blastocysts or isolated ICMs on mitomycin-C inactivated feeder layer. Mechanically isolated ICMs attached and formed primary cell colonies more efficiently than ICMs isolated enzymatically. For derivation of ESCs from poorly defined ICMs intact hatched blastocyst culture was the most successful method. Results of this study implied that although ESCs can be obtained using all three methods used in this study, efficiency varies depending upon the morphology of blastocyst and isolation method used. So, appropriate isolation method must be selected depending on the quality of blastocyst for efficient derivation of ESCs.

Chitosan derivatives for gene transfer: effect of phosphorylcholine and diethylaminoethyl grafts on the in vitro transfection efficiency.

PubMed

Picola, Isadora Pfeifer Dalla; Shi, Qin; Fernandes, Júlio Cesar; Petrônio, Maicon Segalla; Lima, Aline Margarete Furuyama; de Oliveira Tiera, Vera Aparecida; Tiera, Marcio José

2016-11-01

The purpose of this work was to improve the functional properties of chitosan for gene transfer by inserting phosphorylcholine (PC) and diethylaminoethyl (DEAE) groups into the main chain. A series of derivatives containing increasing contents of DEAE and a fixed content of PC groups were synthesized and characterized, aiming to evaluate the effect of these groups on the nanoparticles' properties and the in vitro transfection efficiency. The derivatives were soluble at physiological pH levels and all derivatives were less cytotoxic than the control, the lipid lipofectamine. The obtained derivatives complexed pDNA into nanoparticles with smaller sizes and higher zeta potentials than plain chitosan. The in vitro transfection was performed with nanoparticles prepared at pH 6.3 and 7.4 and the results showed that nanoparticles prepared with derivatives containing 20% of PC groups (PC18-CH) and high degrees of substitution by DEAE (PC20-CH-DEAE100, CH-DEAE80, CH-DEAE100) displayed the better transfection efficiencies in HeLa cells, reaching relative values comparable to lipofectamine. The most effective derivative, PC18CH, was selected for complexation with siRNA and its complexes demonstrated an in vitro knockdown efficiency highly dependent on the N/P ratio. Our combined results indicated that, by means of controlled modifications, the limitations of chitosan can be overcome to obtain more effective carriers based on chitosan, and the derivatives here studied hold potential for in vivo studies.

An improved 3D MoF method based on analytical partial derivatives

NASA Astrophysics Data System (ADS)

Chen, Xiang; Zhang, Xiong

2016-12-01

MoF (Moment of Fluid) method is one of the most accurate approaches among various surface reconstruction algorithms. As other second order methods, MoF method needs to solve an implicit optimization problem to obtain the optimal approximate surface. Therefore, the partial derivatives of the objective function have to be involved during the iteration for efficiency and accuracy. However, to the best of our knowledge, the derivatives are currently estimated numerically by finite difference approximation because it is very difficult to obtain the analytical derivatives of the object function for an implicit optimization problem. Employing numerical derivatives in an iteration not only increase the computational cost, but also deteriorate the convergence rate and robustness of the iteration due to their numerical error. In this paper, the analytical first order partial derivatives of the objective function are deduced for 3D problems. The analytical derivatives can be calculated accurately, so they are incorporated into the MoF method to improve its accuracy, efficiency and robustness. Numerical studies show that by using the analytical derivatives the iterations are converged in all mixed cells with the efficiency improvement of 3 to 4 times.

Differentiated cells are more efficient than adult stem cells for cloning by somatic cell nuclear transfer.

PubMed

Sung, Li-Ying; Gao, Shaorong; Shen, Hongmei; Yu, Hui; Song, Yifang; Smith, Sadie L; Chang, Ching-Chien; Inoue, Kimiko; Kuo, Lynn; Lian, Jin; Li, Ao; Tian, X Cindy; Tuck, David P; Weissman, Sherman M; Yang, Xiangzhong; Cheng, Tao

2006-11-01

Since the creation of Dolly via somatic cell nuclear transfer (SCNT), more than a dozen species of mammals have been cloned using this technology. One hypothesis for the limited success of cloning via SCNT (1%-5%) is that the clones are likely to be derived from adult stem cells. Support for this hypothesis comes from the findings that the reproductive cloning efficiency for embryonic stem cells is five to ten times higher than that for somatic cells as donors and that cloned pups cannot be produced directly from cloned embryos derived from differentiated B and T cells or neuronal cells. The question remains as to whether SCNT-derived animal clones can be derived from truly differentiated somatic cells. We tested this hypothesis with mouse hematopoietic cells at different differentiation stages: hematopoietic stem cells, progenitor cells and granulocytes. We found that cloning efficiency increases over the differentiation hierarchy, and terminally differentiated postmitotic granulocytes yield cloned pups with the greatest cloning efficiency.

AN EFFICIENT AQUEOUS N-HETEROCYCLIZATION OF ANILINE DERIVATIVES: MICROWAVE-ASSISTED SYNTHESIS OF N-ARYL AZACYCLOALKANES

EPA Science Inventory

N-aryl azacycloalkanes, an important class of building blocks in natural product and pharmaceuticals, are synthesized via an efficient and simple eco-friendly protocol that involves double N-alkylation of aniline derivatives. The reaction is accelerated by exposure to microwaves ...

T-Shaped Indan-1,3-dione derivatives as promising electron donors for bulk heterojunction small molecule solar cell

NASA Astrophysics Data System (ADS)

Adhikari, Tham; Solanke, Parmeshwar; Pathak, Dinesh; Wagner, Tomas; Bureš, Filip; Reed, Tyler; Nunzi, Jean-Michel

2017-07-01

We report on the photovoltaic performance of novel T-Shaped Indan-1,3-dione derivatives as donors in a solution processed bulk heterojunction solar cells. Small molecule bulk heterojunction solar cells of these molecules with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) were fabricated and characterized. The preliminary characterization of these devices yielded a PCE of 0.24% and 0.33% for two separate derivatives. These low power conversion efficiencies were attributed to a high surface roughness with a large number of dewetting spots. Doping with 10% Polystyrene in the Indan-1,3-dione derivatives decreases surface roughness and dewetting spots thereby improving the efficiency of the devices. Efficiency of the devices was found as 0.39% and 0.51% for two derivatives after doping with polystyrene. The charge transfer mechanism was studied with photoluminescence quenching. The morphology and packing behavior of molecules were further studied using Atomic Force Microscopy (AFM) and X-ray diffraction (XRD).

Immobilized polysaccharide derivatives: chiral packing materials for efficient HPLC resolution.

PubMed

Ikai, Tomoyuki; Yamamoto, Chiyo; Kamigaito, Masami; Okamoto, Yoshio

2007-01-01

Polysaccharide-based chiral packing materials (CPMs) for high-performance liquid chromatography have frequently been used not only to determine the enantiomeric excess of chiral compounds but also to preparatively resolve a wide range of racemates. However, these CPMs can be used with only a limited number of solvents as mobile phases because some organic solvents, such as tetrahydrofuran, chloroform, and so on, dissolve or swell the polysaccharide derivatives coated on a support, e.g., silica gel, and destroy their packed columns. The limitation of mobile phase selection is sometimes a serious problem for the efficient analytical and preparative resolution of enantiomers. This defect can be resolved by the immobilization of the polysaccharide derivatives onto silica gel. Efficient immobilizations have been attained through the radical copolymerization of the polysaccharide derivatives bearing small amounts of polymerizable residues and also through the polycondensation of the polysaccharide derivatives containing a few percent of 3-(triethoxysilyl)propyl residue. (c) 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

Magnetic nanoparticle supported phosphotungstic acid: An efficient catalyst for the synthesis of xanthene derivatives

NASA Astrophysics Data System (ADS)

Patel, Nipun; Katheriya, Deepak; Dadhania, Harsh; Dadhania, Abhishek

2018-05-01

Magnetic nanoparticle supported phosphotungstic acid (Fe3O4@SiO2-HPW) was applied as a highly efficient catalyst for the synthesis of 14H-dibenzoxanthene derivatives via condensation reaction of 2-naphthol and aryl aldehydes. The catalyst was found highly efficient for the synthesis of xanthene derivatives under solvent free condition. The catalyst showed high activity and stability during the reaction and provided excellent yield of the corresponding products in short reaction time. All the synthesized compounds were characterized through FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. Furthermore, the catalyst is magnetically recoverable and can be reused several times without significant loss of its catalytic activity.

Ethanol production from renewable resources.

PubMed

Gong, C S; Cao, N J; Du, J; Tsao, G T

1999-01-01

Vast amounts of renewable biomass are available for conversion to liquid fuel, ethanol. In order to convert biomass to ethanol, the efficient utilization of both cellulose-derived and hemicellulose-derived carbohydrates is essential. Six-carbon sugars are readily utilized for this purpose. Pentoses, on the other hand, are more difficult to convert. Several metabolic factors limit the efficient utilization of pentoses (xylose and arabinose). Recent developments in the improvement of microbial cultures provide the versatility of conversion of both hexoses and pentoses to ethanol more efficiently. In addition, novel bioprocess technologies offer a promising prospective for the efficient conversion of biomass and recovery of ethanol.

Rhodium-catalyzed NH insertion of pyridyl carbenes derived from pyridotriazoles: a general and efficient approach to 2-picolylamines and imidazo[1,5-a]pyridines.

PubMed

Shi, Yi; Gulevich, Anton V; Gevorgyan, Vladimir

2014-12-15

A general and efficient NH insertion reaction of rhodium pyridyl carbenes derived from pyridotriazoles was developed. Various NH-containing compounds, including amides, anilines, enamines, and aliphatic amines, smoothly underwent the NH insertion reaction to afford 2-picolylamine derivatives. The developed transformation was further utilized in a facile one-pot synthesis of imidazo[1,5-a]pyridines. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combination of counterpropagation artificial neural networks and antioxidant activities for comprehensive evaluation of associated-extraction efficiency of various cyclodextrins in the traditional Chinese formula Xue-Zhi-Ning.

PubMed

Sun, Lili; Yang, Jianwen; Wang, Meng; Zhang, Huijie; Liu, Yanan; Ren, Xiaoliang; Qi, Aidi

2015-11-10

Xue-Zhi-Ning (XZN) is a widely used traditional Chinese medicine formula to treat hyperlipidemia. Recently, cyclodextrins (CDs) have been extensively used to minimize problems relative to medicine bioavailability, such as low solubility and poor stability. The objective of this study was to determine the associated-extraction efficiency of various CDs in XZN. Three various type CDs were evaluated, including native CDs (α-CD, β-CD), hydrophilic CD derivatives (HP-β-CD and Me-β-CD), and ionic CD derivatives (SBE-β-CD and CM-β-CD). An ultra high-performance liquid chromatography (UHPLC) fingerprint was applied to determine the components in CD extracts and original aqueous extract (OAE). A counterpropagation artificial neural network (CP-ANN) was used to analyze the components in different extracts and compare the selective extraction of various CDs. Extraction efficiencies of the various CDs in terms of extracted components follow the ranking, ionic CD derivatives>hydrophilic CD derivatives>native CDs>OAE. Besides, different types of CDs have their own selective extraction and ionic CD derivatives present the strongest associated-extraction efficiency. Antioxidant potentials of various extracts were evaluated by determining the inhibition of spontaneous, H2O2-induced, CCl4-induced and Fe(2+)/ascorbic acid-induced lipid peroxidation (LPO) and analyzing the scavenging capacity for DPPH and hydroxyl radicals. The order of extraction efficiencies of the various CDs relative to antioxidant activities is as follows: SBE-β-CD>CM-β-CD>HP-β-CD>Me-β-CD>β-CD>α-CD. It can be demonstrated that all of the CDs studied increase the extraction efficiency and that ionic CD derivatives (SBE-β-CD and CM-β-CD) present the highest extraction capability in terms of amount extracted and antioxidant activities of extracts. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficient OLEDs Fabricated by Solution Process Based on Carbazole and Thienopyrrolediones Derivatives.

PubMed

Lozano-Hernández, Luis-Abraham; Maldonado, José-Luis; Garcias-Morales, Cesar; Espinosa Roa, Arian; Barbosa-García, Oracio; Rodríguez, Mario; Pérez-Gutiérrez, Enrique

2018-01-30

Four low molecular weight compounds-three of them new, two of them with carbazole (Cz) as functional group and the other two with thienopyrroledione (TPD) group-were used as emitting materials in organic light emitting diodes (OLEDs). Devices were fabricated with the configuration ITO/PEDOT:PSS/emitting material/LiF/Al. The hole injector layer (HIL) and the emitting sheet were deposited by spin coating; LiF and Al were thermally evaporated. OLEDs based on carbazole derivatives show luminances up to 4130 cd/m², large current efficiencies about 20 cd/A and, cautiously, a very impressive External Quantum Efficiency (EQE) up to 9.5%, with electroluminescence peaks located around 490 nm (greenish blue region). Whereas, devices manufactured with TPD derivatives, present luminance up to 1729 cd/m², current efficiencies about 4.5 cd/A and EQE of 1.5%. These results are very competitive regarding previous reported materials/devices.

Efficient computation of the Grünwald-Letnikov fractional diffusion derivative using adaptive time step memory

NASA Astrophysics Data System (ADS)

MacDonald, Christopher L.; Bhattacharya, Nirupama; Sprouse, Brian P.; Silva, Gabriel A.

2015-09-01

Computing numerical solutions to fractional differential equations can be computationally intensive due to the effect of non-local derivatives in which all previous time points contribute to the current iteration. In general, numerical approaches that depend on truncating part of the system history while efficient, can suffer from high degrees of error and inaccuracy. Here we present an adaptive time step memory method for smooth functions applied to the Grünwald-Letnikov fractional diffusion derivative. This method is computationally efficient and results in smaller errors during numerical simulations. Sampled points along the system's history at progressively longer intervals are assumed to reflect the values of neighboring time points. By including progressively fewer points backward in time, a temporally 'weighted' history is computed that includes contributions from the entire past of the system, maintaining accuracy, but with fewer points actually calculated, greatly improving computational efficiency.

Simultaneous suppression of TGF-β and ERK signaling contributes to the highly efficient and reproducible generation of mouse embryonic stem cells from previously considered refractory and non-permissive strains.

PubMed

Hassani, Seyedeh-Nafiseh; Totonchi, Mehdi; Farrokhi, Ali; Taei, Adeleh; Larijani, Mehran Rezaei; Gourabi, Hamid; Baharvand, Hossein

2012-06-01

Mouse embryonic stem cells (ESCs) are pluripotent stem cell lines derived from pre-implantation embryos. The efficiency of mESC generation is affected by genetic variation in mice; that is, some mouse strains are refractory or non-permissive to ESC establishment. Developing an efficient method to derive mESCs from strains of various genetic backgrounds should be valuable for establishment of ESCs in various mammalian species. In the present study, we identified dual inhibition of TGF-β and ERK1/2, by SB431542 and PD0325901, respectively led to the highly efficient and reproducible generation of mESC lines from NMRI, C57BL/6, BALB/c, DBA/2, and FVB/N strains, which previously considered refractory or non-permissive for ESC establishment. These mESCs expressed pluripotency markers and retained the capacity to differentiate into derivatives of all three germ layers. The evaluated lines exhibited high rates of chimerism when reintroduced into blastocysts. To our knowledge, this is the first report of efficient (100%) mESC lines generation from different genetic backgrounds. The application of these two inhibitors will not only solve the problems of mESC derivation but also clarifies new signaling pathways in pluripotent mESCs.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes in the Treatment of Eye Diseases.

PubMed

Harrell, C Randall; Simovic Markovic, Bojana; Fellabaum, Crissy; Arsenijevic, Aleksandar; Djonov, Valentin; Arsenijevic, Nebojsa; Volarevic, Vladislav

2018-05-18

Mesenchymal stem cells (MSCs) were, due to their immunomodulatory and pro-angiogenic characteristics, extensively explored as new therapeutic agents in cell-based therapy of uveitis, glaucoma, retinal and ocular surface diseases.Since it was recently revealed that exosomes play an important role in biological functions of MSCs, herewith we summarized current knowledge about the morphology, structure, phenotype and functional characteristics of MSC-derived exosomes emphasizing their therapeutic potential in the treatment of eye diseases.MSC-derived exosomes were as efficient as transplanted MSCs in limiting the extent of eye injury and inflammation. Immediately after intravitreal injection, MSC-derived exosomes, due to nano-dimension, diffused rapidly throughout the retina and significantly attenuated retinal damage and inflammation. MSC-derived exosomes successfully delivered trophic and immunomodulatory factors to the inner retina and efficiently promoted survival and neuritogenesis of injured retinal ganglion cells. MSC-derived exosomes efficiently suppressed migration of inflammatory cells, attenuated detrimental Th1 and Th17 cell-driven immune response and ameliorated experimental autoimmune uveitis. MSC-derived exosomes were able to fuse with the lysosomes within corneal cells, enabling delivering of MSC-derived active β-glucuronidase and consequent catabolism of accumulated glycosaminoglycans, indicating their therapeutic potential in the treatment of Mucopolysaccharidosis VII (Sly Syndrome). Importantly, beneficent effects were noticed only in animals that received MSC-derived exosomes and were not seen after therapy with fibroblasts-derived exosomes confirming specific therapeutic potential of MSCs and their products in the treatment of eye diseases.In conclusion, MSC-derived exosomes represent potentially new therapeutic agents in the therapy of degenerative and inflammatory ocular diseases.

The maximum efficiency of nano heat engines depends on more than temperature

NASA Astrophysics Data System (ADS)

Woods, Mischa; Ng, Nelly; Wehner, Stephanie

Sadi Carnot's theorem regarding the maximum efficiency of heat engines is considered to be of fundamental importance in the theory of heat engines and thermodynamics. Here, we show that at the nano and quantum scale, this law needs to be revised in the sense that more information about the bath other than its temperature is required to decide whether maximum efficiency can be achieved. In particular, we derive new fundamental limitations of the efficiency of heat engines at the nano and quantum scale that show that the Carnot efficiency can only be achieved under special circumstances, and we derive a new maximum efficiency for others. A preprint can be found here arXiv:1506.02322 [quant-ph] Singapore's MOE Tier 3A Grant & STW, Netherlands.

Characterization of basic amino acids-conjugated PAMAM dendrimers as gene carriers for human adipose-derived mesenchymal stem cells.

PubMed

Bae, Yoonhee; Lee, Sunray; Green, Eric S; Park, Jung Hyun; Ko, Kyung Soo; Han, Jin; Choi, Joon Sig

2016-03-30

Since mesenchymal stem cells (MSCs) can self-renew and differentiate into multiple cell types, the delivery of genes to this type of cell can be an important tool in the emerging field of tissue regeneration and engineering. However, development of more efficient and safe nonviral vectors for gene delivery to stem cells in particular still remains a great challenge. In this study, we describe a group of nonviral gene delivery vectors, conjugated PAMAM derivatives (PAMAM-H-R, PAMAM-H-K, and PAMAM-H-O), displaying affinity toward human adipose-derived mesenchymal stem cells (AD-MSCs). Transfection efficiency using pDNA encoding for luciferase (Luc) and enhanced green fluorescent protein (EGFP), and cytotoxicity assays were performed in human AD-MSCs. The results show that transfection efficiencies of conjugated PAMAM derivatives are improved significantly compared to native PAMAM dendrimer, and that among PAMAM derivatives, cytotoxicity of PAMAM-H-K and PAMAM-H-O were very low. Also, treatment of human AD-MSCs to polyplex formation in conjugated PAMAM derivatives, their cellular uptake and localization were analyzed by flow cytometry and confocal microscopy. Copyright © 2016 Elsevier B.V. All rights reserved.

Simple formalism for efficient derivatives and multi-determinant expansions in quantum Monte Carlo

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

Filippi, Claudia, E-mail: c.filippi@utwente.nl; Assaraf, Roland, E-mail: assaraf@lct.jussieu.fr; Moroni, Saverio, E-mail: moroni@democritos.it

2016-05-21

We present a simple and general formalism to compute efficiently the derivatives of a multi-determinant Jastrow-Slater wave function, the local energy, the interatomic forces, and similar quantities needed in quantum Monte Carlo. Through a straightforward manipulation of matrices evaluated on the occupied and virtual orbitals, we obtain an efficiency equivalent to algorithmic differentiation in the computation of the interatomic forces and the optimization of the orbital parameters. Furthermore, for a large multi-determinant expansion, the significant computational gain afforded by a recently introduced table method is here extended to the local value of any one-body operator and to its derivatives, inmore » both all-electron and pseudopotential calculations.« less

Efficient Generation of β-Globin-Expressing Erythroid Cells Using Stromal Cell-Derived Induced Pluripotent Stem Cells from Patients with Sickle Cell Disease.

PubMed

Uchida, Naoya; Haro-Mora, Juan J; Fujita, Atsushi; Lee, Duck-Yeon; Winkler, Thomas; Hsieh, Matthew M; Tisdale, John F

2017-03-01

Human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells represent an ideal source for in vitro modeling of erythropoiesis and a potential alternative source for red blood cell transfusions. However, iPS cell-derived erythroid cells predominantly produce ε- and γ-globin without β-globin production. We recently demonstrated that ES cell-derived sacs (ES sacs), known to express hemangioblast markers, allow for efficient erythroid cell generation with β-globin production. In this study, we generated several iPS cell lines derived from bone marrow stromal cells (MSCs) and peripheral blood erythroid progenitors (EPs) from sickle cell disease patients, and evaluated hematopoietic stem/progenitor cell (HSPC) generation after iPS sac induction as well as subsequent erythroid differentiation. MSC-derived iPS sacs yielded greater amounts of immature hematopoietic progenitors (VEGFR2 + GPA-), definitive HSPCs (CD34 + CD45+), and megakaryoerythroid progenitors (GPA + CD41a+), as compared to EP-derived iPS sacs. Erythroid differentiation from MSC-derived iPS sacs resulted in greater amounts of erythroid cells (GPA+) and higher β-globin (and βS-globin) expression, comparable to ES sac-derived cells. These data demonstrate that human MSC-derived iPS sacs allow for more efficient erythroid cell generation with higher β-globin production, likely due to heightened emergence of immature progenitors. Our findings should be important for iPS cell-derived erythroid cell generation. Stem Cells 2017;35:586-596. © 2016 AlphaMed Press.

Determinants of the efficiency of photon upconversion by triplet-triplet annihilation in the solid state: zinc porphyrin derivatives in PVA.

PubMed

Rautela, Ranjana; Joshi, Neeraj K; Novakovic, Sacha; Wong, Wallace W H; White, Jonathan M; Ghiggino, Kenneth P; Paige, Matthew F; Steer, Ronald P

2017-08-30

Spectroscopic, photophysical and computational studies designed to expose and explain the differences in the efficiencies of non-coherent photon upconversion (NCPU) by triplet-triplet annihilation (TTA) have been carried out for a new series of alkyl-substituted diphenyl and tetraphenyl zinc porphyrins, both in fluid solution and in solid films. Systematic variations in the alkyl-substitution of the phenyl groups in both the di- and tetraphenyl porphyrins introduces small, but well-understood changes in their spectroscopic and photophysical properties and in their TTA efficiencies. In degassed toluene solution TTA occurs for all derivatives and produces the fluorescent S 2 product states in all cases. In PVA matrices, however, none of the di-phenylporphyrins exhibit measurable NCPU whereas all the tetraphenyl-substituted compounds remain upconversion-active. In PVA the NCPU efficiencies of the zinc tetraphenylporphyrins vary significantly with their steric characteristics; the most sterically crowded tetraphenyl derivative exhibits the greatest efficiency. DFT-D computations have been undertaken and help reveal the sources of these differences.

Synthesis of a Monophosphoryl Derivative of Escherichia coli Lipid A and Its Efficient Coupling to a Tumor-Associated Carbohydrate Antigen

PubMed Central

Tang, Shouchu; Wang, Qianli

2010-01-01

Monophosphoryl lipid A is a safe and potent immunostimulant and vaccine adjuvant, which is potentially useful for the development of effective carbohydrate-based conjugate vaccines. This paper presented a convergent and efficient synthesis of a monophosphoryl derivative of E. coli lipid A having an alkyne functionality at the reducing end, which is suitable for the coupling with various molecules. The coupling of this derivative to an N-modified analog of tumor-associated antigen GM3 by click chemistry is also presented. PMID:19943286

Human Adipose-Derived Stem Cells Labeled with Plasmonic Gold Nanostars for Cellular Tracking and Photothermal Cancer Cell Ablation.

PubMed

Shammas, Ronnie L; Fales, Andrew M; Crawford, Bridget M; Wisdom, Amy J; Devi, Gayathri R; Brown, David A; Vo-Dinh, Tuan; Hollenbeck, Scott T

2017-04-01

Gold nanostars are unique nanoplatforms that can be imaged in real time and transform light energy into heat to ablate cells. Adipose-derived stem cells migrate toward tumor niches in response to chemokines. The ability of adipose-derived stem cells to migrate and integrate into tumors makes them ideal vehicles for the targeted delivery of cancer nanotherapeutics. To test the labeling efficiency of gold nanostars, undifferentiated adipose-derived stem cells were incubated with gold nanostars and a commercially available nanoparticle (Qtracker), then imaged using two-photon photoluminescence microscopy. The effects of gold nanostars on cell phenotype, proliferation, and viability were assessed with flow cytometry, 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide metabolic assay, and trypan blue, respectively. Trilineage differentiation of gold nanostar-labeled adipose-derived stem cells was induced with the appropriate media. Photothermolysis was performed on adipose-derived stem cells cultured alone or in co-culture with SKBR3 cancer cells. Efficient uptake of gold nanostars occurred in adipose-derived stem cells, with persistence of the luminescent signal over 4 days. Labeling efficiency and signal quality were greater than with Qtracker. Gold nanostars did not affect cell phenotype, viability, or proliferation, and exhibited stronger luminescence than Qtracker throughout differentiation. Zones of complete ablation surrounding the gold nanostar-labeled adipose-derived stem cells were observed following photothermolysis in both monoculture and co-culture models. Gold nanostars effectively label adipose-derived stem cells without altering cell phenotype. Once labeled, photoactivation of gold nanostar-labeled adipose-derived stem cells ablates neighboring cancer cells, demonstrating the potential of adipose-derived stem cells as a vehicle for the delivery of site-specific cancer therapy.

Efficient production of platelets from mouse embryonic stem cells by enforced expression of Gata2 in late hemogenic endothelial cells

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

Kawaguchi, Manami; Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510; Kitajima, Kenji

Platelets are essential for blood circulation and coagulation. Previous study indicated that overexpression of Gata2 in differentiated mouse embryonic stem cells (ESCs) resulted in robust induction of megakaryocytes (Mks). To evaluate platelet production capacity of the Gata2-induced ESC-derived Mks, we generated iGata2-ESC line carrying the doxycycline-inducible Gata2 expression cassette. When doxycycline was added to day 5 hemogenic endothelial cells in the in vitro differentiation culture of iGata2-ESCs, c-Kit{sup −}Tie2{sup −}CD41{sup +} Mks were predominantly generated. These iGata2-ESC-derived Mks efficiently produced CD41{sup +}CD42b{sup +}CD61{sup +} platelets and adhered to fibrinogen-coated glass coverslips in response to thrombin stimulation. Transmission electron microscopy analysis demonstratedmore » that the iGata2-ESC-derived platelets were discoid-shaped with α-granules and an open canalicular system, but were larger than peripheral blood platelets in size. These results demonstrated that an enforced expression of Gata2 in late HECs of differentiated ESCs efficiently promotes megakaryopoiesis followed by platelet production. This study provides valuable information for ex vivo platelet production from human pluripotent stem cells in future. -- Highlights: •Megakaryocytes are efficiently induced by Gata2 from ESC-derived day 5 HECs. •Gata2-induced ESC-derived megakaryocytes are c-Kit{sup −}Tie2{sup −}CD41{sup +}. •Gata2-induced ESC-derived megakaryocytes produce larger discoid-shaped platelets. •Gata2-induced ESC-derived platelets bind fibrinogen upon thrombin stimulation.« less

Efficient Generation of iPS Cells from Skeletal Muscle Stem Cells

PubMed Central

Tan, Kah Yong; Eminli, Sarah; Hettmer, Simone; Hochedlinger, Konrad; Wagers, Amy J.

2011-01-01

Reprogramming of somatic cells into inducible pluripotent stem cells generally occurs at low efficiency, although what limits reprogramming of particular cell types is poorly understood. Recent data suggest that the differentiation status of the cell targeted for reprogramming may influence its susceptibility to reprogramming as well as the differentiation potential of the induced pluripotent stem (iPS) cells that are derived from it. To assess directly the influence of lineage commitment on iPS cell derivation and differentiation, we evaluated reprogramming in adult stem cell and mature cell populations residing in skeletal muscle. Our data using clonal assays and a second-generation inducible reprogramming system indicate that stem cells found in mouse muscle, including resident satellite cells and mesenchymal progenitors, reprogram with significantly greater efficiency than their more differentiated daughters (myoblasts and fibroblasts). However, in contrast to previous reports, we find no evidence of biased differentiation potential among iPS cells derived from myogenically committed cells. These data support the notion that adult stem cells reprogram more efficiently than terminally differentiated cells, and argue against the suggestion that “epigenetic memory” significantly influences the differentiation potential of iPS cells derived from distinct somatic cell lineages in skeletal muscle. PMID:22028872

First- and second-order sensitivity analysis of linear and nonlinear structures

NASA Technical Reports Server (NTRS)

Haftka, R. T.; Mroz, Z.

1986-01-01

This paper employs the principle of virtual work to derive sensitivity derivatives of structural response with respect to stiffness parameters using both direct and adjoint approaches. The computations required are based on additional load conditions characterized by imposed initial strains, body forces, or surface tractions. As such, they are equally applicable to numerical or analytical solution techniques. The relative efficiency of various approaches for calculating first and second derivatives is assessed. It is shown that for the evaluation of second derivatives the most efficient approach is one that makes use of both the first-order sensitivities and adjoint vectors. Two example problems are used for demonstrating the various approaches.

77 FR 27822 - Self-Regulatory Organizations; Chicago Board Options Exchange, Incorporated; Notice of Proposed...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-11

... in derivatives markets by requiring the clearing of standardized contracts through regulated [central...- traded derivatives. Competition between appropriately regulated OTC derivatives markets and regulated exchanges will make both sets of markets more efficient and thereby better serve end-users of derivatives.\\8...

Palladium-catalyzed one-pot three- or four-component coupling of aryl iodides, alkynes, and amines through C-N bond cleavage: efficient synthesis of indole derivatives.

PubMed

Hao, Wei; Geng, Weizhi; Zhang, Wen-Xiong; Xi, Zhenfeng

2014-02-24

An efficient synthesis of N-substituted indole derivatives was realized by combining the Pd-catalyzed one-pot multicomponent coupling approach with cleavage of the C(sp(3))-N bonds. Three or four components of aryl iodides, alkynes, and amines were involved in this coupling process. The cyclopentadiene-phosphine ligand showed high efficiency. A variety of aryl iodides, including cyclic and acyclic tertiary amino aryl iodides, and substituted 1-bromo-2-iodobenzene derivatives could be used. Both symmetric and unsymmetric alkynes substituted with alkyl, aryl, or trimethylsilyl groups could be applied. Cyclic secondary amines such as piperidine, morpholine, 4-methylpiperidine, 1-methylpiperazine, 2-methylpiperidine, and acyclic amines including secondary and primary amines all showed good reactivity. Further application of the resulting indole derivatives was demonstrated by the synthesis of benzosilolo[2,3-b]indole. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantitative structure activity relationships of some pyridine derivatives as corrosion inhibitors of steel in acidic medium.

PubMed

El Ashry, El Sayed H; El Nemr, Ahmed; Ragab, Safaa

2012-03-01

Quantum chemical calculations using the density functional theory (B3LYP/6-31G DFT) and semi-empirical AM1 methods were performed on ten pyridine derivatives used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies. Quantum chemical parameters such as total negative charge (TNC) on the molecule, energy of highest occupied molecular orbital (E (HOMO)), energy of lowest unoccupied molecular orbital (E (LUMO)) and dipole moment (μ) as well as linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π) were correlated to corrosion inhibition efficiency of ten pyridine derivatives. A possible correlation between corrosion inhibition efficiencies and structural properties was searched to reduce the number of compounds to be selected for testing from a library of compounds. It was found that theoretical data support the experimental results. The results were used to predict the corrosion inhibition of 24 related pyridine derivatives.

Efficient and rapid derivation of primitive neural stem cells and generation of brain subtype neurons from human pluripotent stem cells.

PubMed

Yan, Yiping; Shin, Soojung; Jha, Balendu Shekhar; Liu, Qiuyue; Sheng, Jianting; Li, Fuhai; Zhan, Ming; Davis, Janine; Bharti, Kapil; Zeng, Xianmin; Rao, Mahendra; Malik, Nasir; Vemuri, Mohan C

2013-11-01

Human pluripotent stem cells (hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, are unique cell sources for disease modeling, drug discovery screens, and cell therapy applications. The first step in producing neural lineages from hPSCs is the generation of neural stem cells (NSCs). Current methods of NSC derivation involve the time-consuming, labor-intensive steps of an embryoid body generation or coculture with stromal cell lines that result in low-efficiency derivation of NSCs. In this study, we report a highly efficient serum-free pluripotent stem cell neural induction medium that can induce hPSCs into primitive NSCs (pNSCs) in 7 days, obviating the need for time-consuming, laborious embryoid body generation or rosette picking. The pNSCs expressed the neural stem cell markers Pax6, Sox1, Sox2, and Nestin; were negative for Oct4; could be expanded for multiple passages; and could be differentiated into neurons, astrocytes, and oligodendrocytes, in addition to the brain region-specific neuronal subtypes GABAergic, dopaminergic, and motor neurons. Global gene expression of the transcripts of pNSCs was comparable to that of rosette-derived and human fetal-derived NSCs. This work demonstrates an efficient method to generate expandable pNSCs, which can be further differentiated into central nervous system neurons and glia with temporal, spatial, and positional cues of brain regional heterogeneity. This method of pNSC derivation sets the stage for the scalable production of clinically relevant neural cells for cell therapy applications in good manufacturing practice conditions.

An efficient synthesis of tetramic acid derivatives with extended conjugation from L-Ascorbic Acid

PubMed Central

Singh, Biswajit K; Bisht, Surendra S; Tripathi, Rama P

2006-01-01

Background Tetramic acids with polyenyl substituents are an important class of compounds in medicinal chemistry. Both solid and solution phase syntheses of such molecules have been reported recently. Thiolactomycin, a clinical candidate for treatment of tuberculosis has led to further explorations in this class. We have recently developed an efficient synthesis of tetramic acids derivatives from L- ascorbic acid. In continuation of this work, we have synthesised dienyl tetramic acid derivatives. Results 5,6-O-Isopropylidene-ascorbic acid on reaction with DBU led to the formation of tetronolactonyl allyl alcohol, which on oxidation with pyridinium chlorochromate gave the respective tetranolactonyl allylic aldehydes. Wittig olefination followed by reaction of the resulting tetranolactonyl dienyl esters with different amines resulted in the respective 5-hydroxy lactams. Subsequent dehydration of the hydroxy lactams with p-toluene sulphonic acid afforded the dienyl tetramic acid derivatives. All reactions were performed at ambient temperature and the yields are good. Conclusion An efficient and practical method for the synthesis of dienyl tetramic acid derivatives from inexpensive and easily accessible ascorbic acid has been developed. The compounds bear structural similarities to the tetramic acid based polyenic antibiotics and thus this method offers a new and short route for the synthesis of tetramic acid derivatives of biological significance. PMID:17147830

An efficient synthesis of tetramic acid derivatives with extended conjugation from L-ascorbic acid.

PubMed

Singh, Biswajit K; Bisht, Surendra S; Tripathi, Rama P

2006-12-06

Tetramic acids with polyenyl substituents are an important class of compounds in medicinal chemistry. Both solid and solution phase syntheses of such molecules have been reported recently. Thiolactomycin, a clinical candidate for treatment of tuberculosis has led to further explorations in this class. We have recently developed an efficient synthesis of tetramic acids derivatives from L-ascorbic acid. In continuation of this work, we have synthesised dienyl tetramic acid derivatives. 5,6-O-isopropylidene-ascorbic acid on reaction with DBU led to the formation of tetronolactonyl allyl alcohol, which on oxidation with pyridinium chlorochromate gave the respective tetranolactonyl allylic aldehydes. Wittig olefination followed by reaction of the resulting tetranolactonyl dienyl esters with different amines resulted in the respective 5-hydroxy lactams. Subsequent dehydration of the hydroxy lactams with p-toluene sulphonic acid afforded the dienyl tetramic acid derivatives. All reactions were performed at ambient temperature and the yields are good. An efficient and practical method for the synthesis of dienyl tetramic acid derivatives from inexpensive and easily accessible ascorbic acid has been developed. The compounds bear structural similarities to the tetramic acid based polyenic antibiotics and thus this method offers a new and short route for the synthesis of tetramic acid derivatives of biological significance.

Bioavailability studies and anticancer properties of malvidin based anthocyanins, pyranoanthocyanins and non-oxonium derivatives.

PubMed

Oliveira, Hélder; Wu, Nao; Zhang, Qian; Wang, Jingyi; Oliveira, Joana; de Freitas, Victor; Mateus, Nuno; He, Jingren; Fernandes, Iva

2016-05-18

In this study, the gastric transport efficiency of malvidin-3-glucoside and several derivatives was assayed on the MKN-28 cell model. The transport efficiency was found to increase for all compounds with the incubation time. Pyranoanthocyanins may slightly impair transport efficiency levels in comparison with native anthocyanins. Among the pyranoanthocyanin derivatives the presence of the carbonyl group and the absence of charge were important for the transport efficiency percentage of oxovitisin and apparently compensated the negative effect associated with the additional ring. Moreover, the antiproliferative properties of these compounds in the MCF-7 cancer cell line were assayed, oxovitisin being the most effective compound in inhibiting the proliferation of MCF-7 cells. Also, a kinetic incorporation of oxovitisin was assayed revealing that this pyranoanthocyanin is quickly incorporated into cells. This study confirms the importance of the natural micro-oxidative processes that occur during the ageing of anthocyanin-containing food and their impact on their bioavailability and bioactivity properties.

High-Efficiency and High-Power Mid-Wave Infrared Cascade Lasers

DTIC Science & Technology

2012-10-01

internal quantum efficiency () and factor (2) is usually called the optical extraction efficiency (). The optical extraction efficiency ... quantum efficiency involves more fundamental parameters corresponding to the microscopic processes of the device operation, nevertheless, it can be...deriving parameters such as the internal quantum efficiency of a QC laser, the entire injector miniband can be treated as a single virtual state

Organic Semiconductors for Sprayable Solar Cells: Improving Stability and Efficiency

DTIC Science & Technology

2008-03-25

adopt a bulk heterojunction approach (where donor and acceptor are mixed before deposition). This decision immediately removed pentacene - based...derivative (ADTz) was the first screened, and unfortunately did not yield any photovoltaic performance. The fullerene adduct of pentacene and C60 was...continue). The most encouraging acceptor was the dicyano pentacene chromophore (DC_Pn). The derivatives shown above varied in efficiency from

Organocatalytic sequential α-amination/Corey-Chaykovsky reaction of aldehydes: a high yield synthesis of 4-hydroxypyrazolidine derivatives.

PubMed

Kumar, B Senthil; Venkataramasubramanian, V; Sudalai, Arumugam

2012-05-18

A tandem reaction of in situ generated α-amino aldehydes with dimethyloxosulfonium methylide under Corey-Chaykovsky reaction conditions proceeds efficiently to give 4-hydroxypyrazolidine derivatives in high yields with excellent enantio- and diastereoselectivities. This organocatalytic sequential method provides for the efficient synthesis of anti-1,2-aminoalcohols, structural subunits present in several bioactive molecules as well.

Efficient Estimation of the Standardized Value

ERIC Educational Resources Information Center

Longford, Nicholas T.

2009-01-01

We derive an estimator of the standardized value which, under the standard assumptions of normality and homoscedasticity, is more efficient than the established (asymptotically efficient) estimator and discuss its gains for small samples. (Contains 1 table and 3 figures.)

Progress on coal-derived fuels for aviation systems

NASA Technical Reports Server (NTRS)

Witcofski, R. D.

1978-01-01

Synthetic aviation kerosene (Syn. Jet-A), liquid methane (LCH4), and liquid hydrogen (LH2) appear to be the most promising coal-derived fuels. Liquid hydrogen aircraft configurations, their fuel systems, and their ground requirements at the airport are identified. These aircraft appear viable, particularly for long haul use, where aircraft fueled with coal derived LH2 would consume 9 percent less coal resources than would aircraft fueled with coal derived Syn. Jet-A. Distribution of hydrogen from the point of manufacture to airports may pose problems. Synthetic JET-A would appear to cause fewer concerns to the air transportation industry. Of the three candidate fuels, LCH4 is the most energy efficient to produce, and an aircraft fueled with coal derived LCH4 may provide both the most efficient utilization of coal resources and the least expensive ticket as well.

Estimation efficiency of usage satellite derived and modelled biophysical products for yield forecasting

NASA Astrophysics Data System (ADS)

Kolotii, Andrii; Kussul, Nataliia; Skakun, Sergii; Shelestov, Andrii; Ostapenko, Vadim; Oliinyk, Tamara

2015-04-01

Efficient and timely crop monitoring and yield forecasting are important tasks for ensuring of stability and sustainable economic development [1]. As winter crops pay prominent role in agriculture of Ukraine - the main focus of this study is concentrated on winter wheat. In our previous research [2, 3] it was shown that usage of biophysical parameters of crops such as FAPAR (derived from Geoland-2 portal as for SPOT Vegetation data) is far more efficient for crop yield forecasting to NDVI derived from MODIS data - for available data. In our current work efficiency of usage such biophysical parameters as LAI, FAPAR, FCOVER (derived from SPOT Vegetation and PROBA-V data at resolution of 1 km and simulated within WOFOST model) and NDVI product (derived from MODIS) for winter wheat monitoring and yield forecasting is estimated. As the part of crop monitoring workflow (vegetation anomaly detection, vegetation indexes and products analysis) and yield forecasting SPIRITS tool developed by JRC is used. Statistics extraction is done for landcover maps created in SRI within FP-7 SIGMA project. Efficiency of usage satellite based and modelled with WOFOST model biophysical products is estimated. [1] N. Kussul, S. Skakun, A. Shelestov, O. Kussul, "Sensor Web approach to Flood Monitoring and Risk Assessment", in: IGARSS 2013, 21-26 July 2013, Melbourne, Australia, pp. 815-818. [2] F. Kogan, N. Kussul, T. Adamenko, S. Skakun, O. Kravchenko, O. Kryvobok, A. Shelestov, A. Kolotii, O. Kussul, and A. Lavrenyuk, "Winter wheat yield forecasting in Ukraine based on Earth observation, meteorological data and biophysical models," International Journal of Applied Earth Observation and Geoinformation, vol. 23, pp. 192-203, 2013. [3] Kussul O., Kussul N., Skakun S., Kravchenko O., Shelestov A., Kolotii A, "Assessment of relative efficiency of using MODIS data to winter wheat yield forecasting in Ukraine", in: IGARSS 2013, 21-26 July 2013, Melbourne, Australia, pp. 3235 - 3238.

Compatibility of Segments of Thermoelectric Generators

NASA Technical Reports Server (NTRS)

Snyder, G. Jeffrey; Ursell, Tristan

2009-01-01

A method of calculating (usually for the purpose of maximizing) the power-conversion efficiency of a segmented thermoelectric generator is based on equations derived from the fundamental equations of thermoelectricity. Because it is directly traceable to first principles, the method provides physical explanations in addition to predictions of phenomena involved in segmentation. In comparison with the finite-element method used heretofore to predict (without being able to explain) the behavior of a segmented thermoelectric generator, this method is much simpler to implement in practice: in particular, the efficiency of a segmented thermoelectric generator can be estimated by evaluating equations using only hand-held calculator with this method. In addition, the method provides for determination of cascading ratios. The concept of cascading is illustrated in the figure and the definition of the cascading ratio is defined in the figure caption. An important aspect of the method is its approach to the issue of compatibility among segments, in combination with introduction of the concept of compatibility within a segment. Prior approaches involved the use of only averaged material properties. Two materials in direct contact could be examined for compatibility with each other, but there was no general framework for analysis of compatibility. The present method establishes such a framework. The mathematical derivation of the method begins with the definition of reduced efficiency of a thermoelectric generator as the ratio between (1) its thermal-to-electric power-conversion efficiency and (2) its Carnot efficiency (the maximum efficiency theoretically attainable, given its hot- and cold-side temperatures). The derivation involves calculation of the reduced efficiency of a model thermoelectric generator for which the hot-side temperature is only infinitesimally greater than the cold-side temperature. The derivation includes consideration of the ratio (u) between the electric current and heat-conduction power and leads to the concept of compatibility factor (s) for a given thermoelectric material, defined as the value of u that maximizes the reduced efficiency of the aforementioned model thermoelectric generator.

Eco-efficient one-pot synthesis of quinazoline-2,4(1H,3H)-diones at room temperature in water.

PubMed

Tian, Xin-Chuan; Huang, Xing; Wang, Dan; Gao, Feng

2014-01-01

An efficient one-pot synthesis of quinazoline-2,4(1H,3H)-diones was developed. First, the reactions of anthranilic acid derivatives with potassium cyanate afforded the corresponding urea derivatives. Then, cyclization of the urea derivatives with NaOH afforded the monosodium salts of benzoylene urea. Finally, HCl treatment afforded the desired products in near-quantitative yields. This is an eco-efficient method because all the reactions were carried out in water, and the desired products were obtained simply by filtration. The aqueous filtrate was the only waste generated from the reaction. We scaled up the reaction to 1 kg starting material, thus establishing an alternative approach for the green synthesis of quinazoline-2,4(1H,3H)-diones in the chemical and pharmaceutical industries.

Galactose Derivative-Modified Nanoparticles for Efficient siRNA Delivery to Hepatocellular Carcinoma.

PubMed

Huang, Kuan-Wei; Lai, Yu-Tsung; Chern, Guann-Jen; Huang, Shao-Feng; Tsai, Chia-Lung; Sung, Yun-Chieh; Chiang, Cheng-Chin; Hwang, Pi-Bei; Ho, Ting-Lun; Huang, Rui-Lin; Shiue, Ting-Yun; Chen, Yunching; Wang, Sheng-Kai

2018-05-29

Successful siRNA therapy requires suitable delivery systems with targeting moieties such as small molecules, peptides, antibodies, or aptamers. Galactose (Gal) residues recognized by the asialoglycoprotein receptor (ASGPR) can serve as potent targeting moieties for hepatocellular carcinoma (HCC) cells. However, efficient targeting to HCC via galactose moieties rather than normal liver tissues in HCC patients remains a challenge. To achieve more efficient siRNA delivery in HCC, we synthesized various galactoside derivatives and investigated the siRNA delivery capability of nanoparticles modified with those galactoside derivatives. In this study, we assembled lipid/calcium/phosphate nanoparticles (LCP NPs) conjugated with eight types of galactoside derivatives and demonstrated that phenyl β-d-galactoside-decorated LCP NPs (L4-LCP NPs) exhibited a superior siRNA delivery into HCC cells compared to normal hepatocytes. VEGF siRNAs delivered by L4-LCP NPs downregulated VEGF expression in HCC in vitro and in vivo and led to a potent antiangiogenic effect in the tumor microenvironment of a murine orthotopic HCC model. The efficient delivery of VEGF siRNA by L4-LCP NPs that resulted in significant tumor regression indicates that phenyl galactoside could be a promising HCC-targeting ligand for therapeutic siRNA delivery to treat liver cancer.

Human Ocular Epithelial Cells Endogenously Expressing SOX2 and OCT4 Yield High Efficiency of Pluripotency Reprogramming.

PubMed

Poon, Ming-Wai; He, Jia; Fang, Xiaowei; Zhang, Zhao; Wang, Weixin; Wang, Junwen; Qiu, Fangfang; Tse, Hung-Fat; Li, Wei; Liu, Zuguo; Lian, Qizhou

2015-01-01

A variety of pluripotency reprogramming frequencies from different somatic cells has been observed, indicating cell origin is a critical contributor for efficiency of pluripotency reprogramming. Identifying the cell sources for efficient induced pluripotent stem cells (iPSCs) generation, and defining its advantages or disadvantages on reprogramming, is therefore important. Human ocular tissue-derived conjunctival epithelial cells (OECs) exhibited endogenous expression of reprogramming factors OCT4A (the specific OCT 4 isoform on pluripotency reprogramming) and SOX2. We therefore determined whether OECs could be used for high efficiency of iPSCs generation. We compared the endogenous expression levels of four pluripotency factors and the pluripotency reprograming efficiency of human OECs with that of ocular stromal cells (OSCs). Real-time PCR, microarray analysis, Western blotting and immunostaining assays were employed to compare OECiPSCs with OSCiPSCs on molecular bases of reprogramming efficiency and preferred lineage-differentiation potential. Using the traditional KMOS (KLF4, C-MYC, OCT4 and SOX2) reprogramming protocol, we confirmed that OECs, endogenously expressing reprogramming factors OCT4A and SOX2, yield very high efficiency of iPSCs generation (~1.5%). Furthermore, higher efficiency of retinal pigmented epithelial differentiation (RPE cells) was observed in OECiPSCs compared to OSCiPSCs or skin fibroblast iMR90iPSCs. The findings in this study suggest that conjunctival-derived epithelial (OECs) cells can be easier converted to iPSCs than conjunctival-derived stromal cells (OSCs). This cell type may also have advantages in retinal pigmented epithelial differentiation.

Efficient anaerobic transformation of raw wheat straw by a robust cow rumen-derived microbial consortium.

PubMed

Lazuka, Adèle; Auer, Lucas; Bozonnet, Sophie; Morgavi, Diego P; O'Donohue, Michael; Hernandez-Raquet, Guillermina

2015-11-01

A rumen-derived microbial consortium was enriched on raw wheat straw as sole carbon source in a sequential batch-reactor (SBR) process under strict mesophilic anaerobic conditions. After five cycles of enrichment the procedure enabled to select a stable and efficient lignocellulolytic microbial consortium, mainly constituted by members of Firmicutes and Bacteroidetes phyla. The enriched community, designed rumen-wheat straw-derived consortium (RWS) efficiently hydrolyzed lignocellulosic biomass, degrading 55.5% w/w of raw wheat straw over 15days at 35°C and accumulating carboxylates as main products. Cellulolytic and hemicellulolytic activities, mainly detected on the cell bound fraction, were produced in the earlier steps of degradation, their production being correlated with the maximal lignocellulose degradation rates. Overall, these results demonstrate the potential of RWS to convert unpretreated lignocellulosic substrates into useful chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Second derivatives for approximate spin projection methods

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

Thompson, Lee M.; Hratchian, Hrant P., E-mail: hhratchian@ucmerced.edu

2015-02-07

The use of broken-symmetry electronic structure methods is required in order to obtain correct behavior of electronically strained open-shell systems, such as transition states, biradicals, and transition metals. This approach often has issues with spin contamination, which can lead to significant errors in predicted energies, geometries, and properties. Approximate projection schemes are able to correct for spin contamination and can often yield improved results. To fully make use of these methods and to carry out exploration of the potential energy surface, it is desirable to develop an efficient second energy derivative theory. In this paper, we formulate the analytical secondmore » derivatives for the Yamaguchi approximate projection scheme, building on recent work that has yielded an efficient implementation of the analytical first derivatives.« less

Analytical solution of the nonlinear diffusion equation

NASA Astrophysics Data System (ADS)

Shanker Dubey, Ravi; Goswami, Pranay

2018-05-01

In the present paper, we derive the solution of the nonlinear fractional partial differential equations using an efficient approach based on the q -homotopy analysis transform method ( q -HATM). The fractional diffusion equations derivatives are considered in Caputo sense. The derived results are graphically demonstrated as well.

Derivation of the open-circuit voltage of organic solar cells

NASA Astrophysics Data System (ADS)

Staple, Douglas B.; Oliver, Patricia A. K.; Hill, Ian G.

2014-05-01

Organic photovoltaic cells have improved in efficiency from 1% two decades ago to over 10% today. Continued improvement necessitates a theoretical understanding of the factors determining efficiency. Organic photovoltaic efficiency can be parameterized in terms of open-circuit voltage, short-circuit current, and fill factor. Here we present a theory that explains the dependencies of open-circuit voltage on semiconductor energy levels, light intensity, solar cell and light-source temperatures, charge-carrier recombination, and external fluorescence efficiency. The present theory also explains why recombination at the donor-acceptor heterointerface is a dominant process in heterojunction-based cells. Furthermore, the Carnot efficiency appears, highlighting the connection to basic thermodynamics. The theory presented here is consistent with and builds on the experimental and theoretical observations already in the literature. Crucially, the present theory can be straightforwardly derived in a line-by-line fashion using standard tools from statistical physics.

Effect of co-crystallization on singlet fission efficiency in pentacene derivatives

NASA Astrophysics Data System (ADS)

Wang, Xiaopeng; Sanders, Samuel; Campos, Luis; Sfeir, Matthew; Marom, Noa

Singlet fission (SF), the conversion of one singlet exciton into two triplet excitons, may lead to a twofold increase in the efficiency of organic photovoltaics. Since SF has been observed in crystalline pentacene, this material has drawn interest both experimentally and theoretically. Recently, it has been shown that SF efficiency in rubrene may be improved by modifying the crystal packing. Here, we study the effect of co-crystallization with small molecule H-bond donors on SF efficiency in pentacene derivatives. Five co-crystals are synthetized and their photoluminescence (PL) and absorption spectra are measured. First-principles calculations based on many-body perturbation theory (MBPT) are then employed to study their excitonic properties. By combining experiment and theory, we demonsrate that excitonic properties, including singlet-triplet gaps, exciton binding energies, and exciton localization, are significantly modulated in pentacene co-crystals. Consequently, co-crystallization becomes an effective strategy for improving SF efficiency in molecular crystals of organic semiconductors.

Tactical Synthesis Of Efficient Global Search Algorithms

NASA Technical Reports Server (NTRS)

Nedunuri, Srinivas; Smith, Douglas R.; Cook, William R.

2009-01-01

Algorithm synthesis transforms a formal specification into an efficient algorithm to solve a problem. Algorithm synthesis in Specware combines the formal specification of a problem with a high-level algorithm strategy. To derive an efficient algorithm, a developer must define operators that refine the algorithm by combining the generic operators in the algorithm with the details of the problem specification. This derivation requires skill and a deep understanding of the problem and the algorithmic strategy. In this paper we introduce two tactics to ease this process. The tactics serve a similar purpose to tactics used for determining indefinite integrals in calculus, that is suggesting possible ways to attack the problem.

Gaussian decomposition of high-resolution melt curve derivatives for measuring genome-editing efficiency

PubMed Central

Zaboikin, Michail; Freter, Carl

2018-01-01

We describe a method for measuring genome editing efficiency from in silico analysis of high-resolution melt curve data. The melt curve data derived from amplicons of genome-edited or unmodified target sites were processed to remove the background fluorescent signal emanating from free fluorophore and then corrected for temperature-dependent quenching of fluorescence of double-stranded DNA-bound fluorophore. Corrected data were normalized and numerically differentiated to obtain the first derivatives of the melt curves. These were then mathematically modeled as a sum or superposition of minimal number of Gaussian components. Using Gaussian parameters determined by modeling of melt curve derivatives of unedited samples, we were able to model melt curve derivatives from genetically altered target sites where the mutant population could be accommodated using an additional Gaussian component. From this, the proportion contributed by the mutant component in the target region amplicon could be accurately determined. Mutant component computations compared well with the mutant frequency determination from next generation sequencing data. The results were also consistent with our earlier studies that used difference curve areas from high-resolution melt curves for determining the efficiency of genome-editing reagents. The advantage of the described method is that it does not require calibration curves to estimate proportion of mutants in amplicons of genome-edited target sites. PMID:29300734

Novel flurbiprofen derivatives with improved brain delivery: synthesis, in vitro and in vivo evaluations.

PubMed

Zheng, Dan; Shuai, Xiao; Li, Yanping; Zhou, Peng; Gong, Tao; Sun, Xun; Zhang, Zhirong

2016-09-01

Tarenflurbil (R-flurbiprofen) was acknowledged as a promising candidate in Alzheimer's disease (AD) therapy. However, the Phase III study of tarenflurbil was extremely restricted by its poor delivery efficiency to the brain. To tackle this problem, the novel carriers for tarenflurbil, racemic flurbiprofen (FLU) derivatives (FLU-D1 and FLU-D2) modified by N,N-dimethylethanolamine-related structures were synthesized and characterized. These derivatives showed good safety level in vitro and they possessed much higher cellular uptake efficiency in brain endothelial cells than FLU did. More importantly, the uptake experiments suggested that they were internalized via active transport mechanisms. Biodistribution studies in rats also illustrated a remarkably enhanced accumulation of these derivatives in the brain. FLU-D2, the ester linkage form of these derivatives, achieved a higher brain-targeting efficiency. Its C max and AUC 0- t were enhanced by 12.09-fold and 4.61-fold, respectively compared with those of FLU. Additionally, it could be hydrolyzed by esterase in the brain to release the parent FLU, which might facilitate its therapeutic effect. These in vitro and in vivo results highlighted the improvement of the brain-targeted delivery of FLU by making use of N,N-dimethylethanolamine ligand, with which an active transport mechanism was involved.

Efficient Time-Domain Imaging Processing for One-Stationary Bistatic Forward-Looking SAR Including Motion Errors

PubMed Central

Xie, Hongtu; Shi, Shaoying; Xiao, Hui; Xie, Chao; Wang, Feng; Fang, Qunle

2016-01-01

With the rapid development of the one-stationary bistatic forward-looking synthetic aperture radar (OS-BFSAR) technology, the huge amount of the remote sensing data presents challenges for real-time imaging processing. In this paper, an efficient time-domain algorithm (ETDA) considering the motion errors for the OS-BFSAR imaging processing, is presented. This method can not only precisely handle the large spatial variances, serious range-azimuth coupling and motion errors, but can also greatly improve the imaging efficiency compared with the direct time-domain algorithm (DTDA). Besides, it represents the subimages on polar grids in the ground plane instead of the slant-range plane, and derives the sampling requirements considering motion errors for the polar grids to offer a near-optimum tradeoff between the imaging precision and efficiency. First, OS-BFSAR imaging geometry is built, and the DTDA for the OS-BFSAR imaging is provided. Second, the polar grids of subimages are defined, and the subaperture imaging in the ETDA is derived. The sampling requirements for polar grids are derived from the point of view of the bandwidth. Finally, the implementation and computational load of the proposed ETDA are analyzed. Experimental results based on simulated and measured data validate that the proposed ETDA outperforms the DTDA in terms of the efficiency improvement. PMID:27845757

Potential natural sensitizers extracted from the skin of Canarium odontophyllum fruits for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Lim, Andery; Kumara, N. T. R. N.; Tan, Ai Ling; Mirza, Aminul Huq; Chandrakanthi, R. L. N.; Petra, Mohammad Iskandar; Ming, Lim Chee; Senadeera, G. K. R.; Ekanayake, Piyasiri

2015-03-01

Possibility of use of dye extract from skin samples of a seasonal, indigenous fruit from Borneo, namely Canarium odontophyllum, in dye sensitized solar cells (DSSCs) are explored. Three main groups of flavonoid pigments are detected and these pigments exhibit different UV-vis absorption properties, and hence showing different light harvesting capabilities. When applied in DSSCs. The detected pigment constituents of the extract consist of aurone (maritimein), anthocyanidin (pelargonidin) and anthocyanidin (cyanidin derivatives). When tested in DSSC, the highest conversion efficiency of 1.43% is exhibited by cyanidin derivatives, and this is followed by conversion efficiencies of 0.51% and 0.79% for aurone and pelargonidin, respectively. It is shown that individual pigments, like cyanidin derivatives and pelargonidin, exhibit higher power conversion efficiency when compared to that of C.odontophyllum skin pigment mixture (with a conversion efficiency of only 0.68%). The results indicate a possibility of masking effects of the pigments when used as a mixture. The acidification of C.odontophyllum skin pigments with concentrated hydrochloric acid improves the conversion efficiency of the mixture from 0.68% to 0.99%. The discussion in this paper will draw data and observations from the variation in absorption and adsorption properties, the HOMO-LUMO levels, the energy band gaps and the functional group compositions of the detected flavonoids.

Polypyrrole-derived nitrogen and oxygen co-doped mesoporous carbons as efficient metal-free electrocatalyst for hydrazine oxidation.

PubMed

Meng, Yuying; Zou, Xiaoxin; Huang, Xiaoxi; Goswami, Anandarup; Liu, Zhongwu; Asefa, Tewodros

2014-10-08

We demonstrate that polypyrrole-derived nitrogen and oxygen co-doped mesoporous carbons can serve as efficient, metal-free electrocatalysts for hydrazine oxidation reaction, with low overpotential and high current density. The materials' structures and the nature and type of their included dopants, which can be controlled by varying the synthetic conditions, can affect the electrocatalytic properties of the materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deductive Derivation and Turing-Computerization of Semiparametric Efficient Estimation

PubMed Central

Frangakis, Constantine E.; Qian, Tianchen; Wu, Zhenke; Diaz, Ivan

2015-01-01

Summary Researchers often seek robust inference for a parameter through semiparametric estimation. Efficient semiparametric estimation currently requires theoretical derivation of the efficient influence function (EIF), which can be a challenging and time-consuming task. If this task can be computerized, it can save dramatic human effort, which can be transferred, for example, to the design of new studies. Although the EIF is, in principle, a derivative, simple numerical differentiation to calculate the EIF by a computer masks the EIF’s functional dependence on the parameter of interest. For this reason, the standard approach to obtaining the EIF relies on the theoretical construction of the space of scores under all possible parametric submodels. This process currently depends on the correctness of conjectures about these spaces, and the correct verification of such conjectures. The correct guessing of such conjectures, though successful in some problems, is a nondeductive process, i.e., is not guaranteed to succeed (e.g., is not computerizable), and the verification of conjectures is generally susceptible to mistakes. We propose a method that can deductively produce semiparametric locally efficient estimators. The proposed method is computerizable, meaning that it does not need either conjecturing, or otherwise theoretically deriving the functional form of the EIF, and is guaranteed to produce the desired estimates even for complex parameters. The method is demonstrated through an example. PMID:26237182

Deductive derivation and turing-computerization of semiparametric efficient estimation.

PubMed

Frangakis, Constantine E; Qian, Tianchen; Wu, Zhenke; Diaz, Ivan

2015-12-01

Researchers often seek robust inference for a parameter through semiparametric estimation. Efficient semiparametric estimation currently requires theoretical derivation of the efficient influence function (EIF), which can be a challenging and time-consuming task. If this task can be computerized, it can save dramatic human effort, which can be transferred, for example, to the design of new studies. Although the EIF is, in principle, a derivative, simple numerical differentiation to calculate the EIF by a computer masks the EIF's functional dependence on the parameter of interest. For this reason, the standard approach to obtaining the EIF relies on the theoretical construction of the space of scores under all possible parametric submodels. This process currently depends on the correctness of conjectures about these spaces, and the correct verification of such conjectures. The correct guessing of such conjectures, though successful in some problems, is a nondeductive process, i.e., is not guaranteed to succeed (e.g., is not computerizable), and the verification of conjectures is generally susceptible to mistakes. We propose a method that can deductively produce semiparametric locally efficient estimators. The proposed method is computerizable, meaning that it does not need either conjecturing, or otherwise theoretically deriving the functional form of the EIF, and is guaranteed to produce the desired estimates even for complex parameters. The method is demonstrated through an example. © 2015, The International Biometric Society.

Safety, efficacy and efficiency of laser-assisted IVF in subfertile mutant mouse strains

PubMed Central

Li, Ming-Wen; Kinchen, Kristy L; Vallelunga, Jadine M; Young, Diana L; Wright, Kaleb D K; Gorano, Lisa N; Wasson, Katherine; Lloyd, K C Kent

2013-01-01

In the present report we studied the safety, efficacy and efficiency of using an infrared laser to facilitate IVF by assessing fertilization, development and birth rates after laser-zona drilling (LZD) in 30 subfertile genetically modified (GM) mouse lines. We determined that LZD increased the fertilization rate four to ten times that of regular IVF, thus facilitating the derivation of 26 of 30 (86.7%) GM mouse lines. Cryopreserved two-cell stage embryos derived by LZD-assisted IVF were recovered and developed to blastocysts in vitro at the same rate as frozen–thawed embryos derived by regular IVF. Surprisingly after surgical transfer to pseudopregnant recipients the birth rate of embryos derived by LZD-assisted IVF was significantly lower than that of embryos derived by regular IVF. However this result could be completely mitigated by the addition of 0.25 M sucrose to the culture medium during LZD which caused the oocyte to shrink in volume relative to the perivitelline space. By increasing the distance from the laser target site on the zona pellucida, we hypothesize that the hyperosmotic effect of sucrose reduced the potential for laser-induced cytotoxic thermal damage to the underlying oocytes. With appropriate preparation and cautious application, our results indicate that LZD-assisted IVF is a safe, efficacious and efficient assisted reproductive technology for deriving mutant mouse lines with male factor infertility and subfertility caused by sperm–zona penetration defects. PMID:23315689

In vitro generation of three-dimensional substrate-adherent embryonic stem cell-derived neural aggregates for application in animal models of neurological disorders.

PubMed

Hargus, Gunnar; Cui, Yi-Fang; Dihné, Marcel; Bernreuther, Christian; Schachner, Melitta

2012-05-01

In vitro-differentiated embryonic stem (ES) cells comprise a useful source for cell replacement therapy, but the efficiency and safety of a translational approach are highly dependent on optimized protocols for directed differentiation of ES cells into the desired cell types in vitro. Furthermore, the transplantation of three-dimensional ES cell-derived structures instead of a single-cell suspension may improve graft survival and function by providing a beneficial microenvironment for implanted cells. To this end, we have developed a new method to efficiently differentiate mouse ES cells into neural aggregates that consist predominantly (>90%) of postmitotic neurons, neural progenitor cells, and radial glia-like cells. When transplanted into the excitotoxically lesioned striatum of adult mice, these substrate-adherent embryonic stem cell-derived neural aggregates (SENAs) showed significant advantages over transplanted single-cell suspensions of ES cell-derived neural cells, including improved survival of GABAergic neurons, increased cell migration, and significantly decreased risk of teratoma formation. Furthermore, SENAs mediated functional improvement after transplantation into animal models of Parkinson's disease and spinal cord injury. This unit describes in detail how SENAs are efficiently derived from mouse ES cells in vitro and how SENAs are isolated for transplantation. Furthermore, methods are presented for successful implantation of SENAs into animal models of Huntington's disease, Parkinson's disease, and spinal cord injury to study the effects of stem cell-derived neural aggregates in a disease context in vivo.

Rho kinase inhibitor Y-27632 and Accutase dramatically increase mouse embryonic stem cell derivation.

PubMed

Zhang, Peng; Wu, Xinglong; Hu, Chunchao; Wang, Pengbo; Li, Xiangyun

2012-01-01

Although it has been 30 yr since the development of derivation methods for mouse embryonic stem (ES) cells, the biology of derivation of ES cells is poorly understood and the efficiency varies dramatically between cell lines. Recently, the Rho kinase inhibitor Y-27632 and the cell dissociation reagent Accutase were reported to significantly inhibit apoptosis of human ES cells during passaging. Therefore, in the current study, C57BL/6×129/Sv mouse blastocysts were used to evaluate the effect of the combination of the two reagents instead of using the conventional 129 line in mouse ES cell derivation. The data presented in this study suggests that the combination of Y-27632 and Accutase significantly increases the efficiency of mouse ES cell derivation; furthermore, no negative side effects were observed with Y-27632 and Accutase treatment. The newly established ES cell lines retain stable karyotype, surface markers expression, formed teratomas, and contributed to viable chimeras and germline transmission by tetraploid complementation assay. In addition, Y-27632 improved embryoid body formation of ES cells. During ES cell microinjection, Y-27632 prevented the formation of dissociation-induced cell blebs and facilitates the selection and the capture of intact cells. The methods presented in this study clearly demonstrate that inhibition of Rho kinase with Y-27632 and Accutase dissociation improve the derivation efficiently and reproducibility of mouse ES cell generation which is essential for reducing variability in the results obtained from different cell lines.

Targeting glioblastoma-derived pericytes improves chemotherapeutic outcome.

PubMed

Guerra, Daniel A P; Paiva, Ana E; Sena, Isadora F G; Azevedo, Patrick O; Silva, Walison N; Mintz, Akiva; Birbrair, Alexander

2018-05-14

Glioblastoma is the most common malignant brain cancer in adults, with poor prognosis. The blood-brain barrier limits the arrival of several promising anti-glioblastoma drugs, and restricts the design of efficient therapies. Recently, by using state-of-the-art technologies, including thymidine kinase targeting system in combination with glioblastoma xenograft mouse models, it was revealed that targeting glioblastoma-derived pericytes improves chemotherapy efficiency. Strikingly, ibrutinib treatment enhances chemotherapeutic effectiveness, by targeting pericytes, improving blood-brain barrier permeability, and prolonging survival. This study identifies glioblastoma-derived pericyte as a novel target in the brain tumor microenvironment during carcinogenesis. Here, we summarize and evaluate recent advances in the understanding of pericyte's role in the glioblastoma microenvironment.

Efficient generation of induced pluripotent stem cells from human bone marrow mesenchymal stem cells.

PubMed

Yulin, X; Lizhen, L; Lifei, Z; Shan, F; Ru, L; Kaimin, H; Huang, H

2012-01-01

Ectopic expression of defined sets of genetic factors can reprogramme somatic cells to induced pluripotent stem cells (iPSCs) that closely resemble embryonic stem cells. However, the low reprogramming efficiency is a significant handicap for mechanistic studies and potential clinical application. In this study, we used human bone marrow-derived mesenchymal stem cells (hBMMSCs) as target cells for reprogramming and investigated efficient iPSC generation from hBMMSCs using the compounds of p53 siRNA, valproic acid (VPA) and vitamin C (Vc) with four transcription factors OCT4, SOX2, KLF4, and c-MYC (compound induction system). The synergetic mechanism of the compounds was studied. Our results showed that the compound induction system could efficiently reprogramme hBMMSCs to iPSCs. hBMMSC-derived iPSC populations expressed pluripotent markers and had multi-potential to differentiate into three germ layer-derived cells. p53 siRNA, VPA and Vc had a synergetic effect on cell reprogramming and the combinatorial use of these substances greatly improved the efficiency of iPSC generation by suppressing the expression of p53, decreasing cell apoptosis, up-regulating the expression of the pluripotent gene OCT4 and modifying the cell cycle. Therefore, our study highlights a straightforward method for improving the speed and efficiency of iPSC generation and provides versatile tools for investigating early developmental processes such as haemopoiesis and relevant diseases. In addition, this study provides a paradigm for the combinatorial use of genetic factors and molecules to improve the efficiency of iPSC generation.

Bottromycin derivatives: efficient chemical modifications of the ester moiety and evaluation of anti-MRSA and anti-VRE activities.

PubMed

Kobayashi, Yutaka; Ichioka, Maki; Hirose, Tomoyasu; Nagai, Kenichiro; Matsumoto, Atsuko; Matsui, Hidehiro; Hanaki, Hideaki; Masuma, Rokuro; Takahashi, Yoko; Omura, Satoshi; Sunazuka, Toshiaki

2010-10-15

Novel bottromycin derivatives were synthesized from bottromycin A(2) via a hydrazide derivative as a common intermediate. Seventeen derivatives were subjected to in vitro evaluation against drug-resistant gram-positive bacteria. Some compounds showed potent anti-MRSA and anti-VRE activity, as did bottromycin A(2). Notably, a propyl ketone derivative exhibited good antibacterial activity with excellent metabolite stability. Copyright © 2010 Elsevier Ltd. All rights reserved.

Ferrocene Derived Bifunctional Phosphine-Catalyzed Asymmetric Oxa-[4+2] Cycloaddition of α-Substituted Allenones with Enones.

PubMed

Wang, Huamin; Lu, Weike; Zhang, Junliang

2017-10-04

An efficient ferrocene-derived bifunctional phosphine-catalyzed enantioselective oxa-[4+2] cycloaddition of α-substituted allenones with a broad range of enones is investigated for the preparation of stereodefined dihydropyrans in good to excellent yields (up to 99 %) and excellent enantioselectivity (up to 99 % ee). Furthermore, a series of valuable chiral polyheterocyclic frameworks can be efficiently achieved in good yields with excellent enantioselectivities. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel dextran derivatives with unconventional structure formed in an efficient one-pot reaction.

PubMed

Hotzel, Konrad; Heinze, Thomas

2016-11-03

An efficient one-pot synthesis of new dextran derivatives is described. The functional groups of β-alanine, i.e., the carboxyl- and amine group, are converted independently in one-step by iminium chloride to form products with a single substituent. The dextran N-[(dimethylamino)methylene]-β-alanine ester is formed selectively. The structure of the resulting polymers is unambiguously determined by means of NMR- and FTIR-spectroscopy and elemental analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Some Advanced Concepts in Discrete Aerodynamic Sensitivity Analysis

NASA Technical Reports Server (NTRS)

Taylor, Arthur C., III; Green, Lawrence L.; Newman, Perry A.; Putko, Michele M.

2003-01-01

An efficient incremental iterative approach for differentiating advanced flow codes is successfully demonstrated on a two-dimensional inviscid model problem. The method employs the reverse-mode capability of the automatic differentiation software tool ADIFOR 3.0 and is proven to yield accurate first-order aerodynamic sensitivity derivatives. A substantial reduction in CPU time and computer memory is demonstrated in comparison with results from a straightforward, black-box reverse-mode applicaiton of ADIFOR 3.0 to the same flow code. An ADIFOR-assisted procedure for accurate second-rder aerodynamic sensitivity derivatives is successfully verified on an inviscid transonic lifting airfoil example problem. The method requires that first-order derivatives are calculated first using both the forward (direct) and reverse (adjoinct) procedures; then, a very efficient noniterative calculation of all second-order derivatives can be accomplished. Accurate second derivatives (i.e., the complete Hesian matrices) of lift, wave drag, and pitching-moment coefficients are calculated with respect to geometric shape, angle of attack, and freestream Mach number.

Vector Design Tour de Force: Integrating Combinatorial and Rational Approaches to Derive Novel Adeno-associated Virus Variants

PubMed Central

Marsic, Damien; Govindasamy, Lakshmanan; Currlin, Seth; Markusic, David M; Tseng, Yu-Shan; Herzog, Roland W; Agbandje-McKenna, Mavis; Zolotukhin, Sergei

2014-01-01

Methodologies to improve existing adeno-associated virus (AAV) vectors for gene therapy include either rational approaches or directed evolution to derive capsid variants characterized by superior transduction efficiencies in targeted tissues. Here, we integrated both approaches in one unified design strategy of “virtual family shuffling” to derive a combinatorial capsid library whereby only variable regions on the surface of the capsid are modified. Individual sublibraries were first assembled in order to preselect compatible amino acid residues within restricted surface-exposed regions to minimize the generation of dead-end variants. Subsequently, the successful families were interbred to derive a combined library of ~8 × 105 complexity. Next-generation sequencing of the packaged viral DNA revealed capsid surface areas susceptible to directed evolution, thus providing guidance for future designs. We demonstrated the utility of the library by deriving an AAV2-based vector characterized by a 20-fold higher transduction efficiency in murine liver, now equivalent to that of AAV8. PMID:25048217

Some Advanced Concepts in Discrete Aerodynamic Sensitivity Analysis

NASA Technical Reports Server (NTRS)

Taylor, Arthur C., III; Green, Lawrence L.; Newman, Perry A.; Putko, Michele M.

2001-01-01

An efficient incremental-iterative approach for differentiating advanced flow codes is successfully demonstrated on a 2D inviscid model problem. The method employs the reverse-mode capability of the automatic- differentiation software tool ADIFOR 3.0, and is proven to yield accurate first-order aerodynamic sensitivity derivatives. A substantial reduction in CPU time and computer memory is demonstrated in comparison with results from a straight-forward, black-box reverse- mode application of ADIFOR 3.0 to the same flow code. An ADIFOR-assisted procedure for accurate second-order aerodynamic sensitivity derivatives is successfully verified on an inviscid transonic lifting airfoil example problem. The method requires that first-order derivatives are calculated first using both the forward (direct) and reverse (adjoint) procedures; then, a very efficient non-iterative calculation of all second-order derivatives can be accomplished. Accurate second derivatives (i.e., the complete Hessian matrices) of lift, wave-drag, and pitching-moment coefficients are calculated with respect to geometric- shape, angle-of-attack, and freestream Mach number

Specific and highly efficient condensation of GC and IC DNA by polyaza pyridinophane derivatives.

PubMed

Stojković, Marijana Radić; Gonzalez-Garcia, Jorge; Šupljika, Filip; Galiana-Rosello, Cristina; Guijarro, Lluis; Gazze, Salvatore A; Francis, Lewis W; Piantanida, Ivo; Garcia-Espana, Enrique

2018-04-01

Two bis-polyaza pyridinophane derivatives and their monomeric reference compounds revealed strong interactions with ds-DNA and RNA. The bis-derivatives show a specific condensation of GC- and IC-DNA, which is almost two orders of magnitude more efficient than the well-known condensation agent spermine. The type of condensed DNA was identified as ψ-DNA, characterized by the exceptionally strong CD signals. At variance to the almost silent AT(U) polynucleotides, these strong CD signals allow the determination of GC-condensates at nanomolar nucleobase concentrations. Detailed thermodynamic characterisation by ITC reveals significant differences between the DNA binding of the bis-derivative compounds (enthalpy driven) and that of spermine and of their monomeric counterparts (entropy driven). Atomic force microscopy confirmed GC-DNA compaction by the bis-derivatives and the formation of toroid- and rod-like structures responsible for the ψ-type pattern in the CD spectra. Copyright © 2017 Elsevier B.V. All rights reserved.

Low rank approach to computing first and higher order derivatives using automatic differentiation

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

Reed, J. A.; Abdel-Khalik, H. S.; Utke, J.

2012-07-01

This manuscript outlines a new approach for increasing the efficiency of applying automatic differentiation (AD) to large scale computational models. By using the principles of the Efficient Subspace Method (ESM), low rank approximations of the derivatives for first and higher orders can be calculated using minimized computational resources. The output obtained from nuclear reactor calculations typically has a much smaller numerical rank compared to the number of inputs and outputs. This rank deficiency can be exploited to reduce the number of derivatives that need to be calculated using AD. The effective rank can be determined according to ESM by computingmore » derivatives with AD at random inputs. Reduced or pseudo variables are then defined and new derivatives are calculated with respect to the pseudo variables. Two different AD packages are used: OpenAD and Rapsodia. OpenAD is used to determine the effective rank and the subspace that contains the derivatives. Rapsodia is then used to calculate derivatives with respect to the pseudo variables for the desired order. The overall approach is applied to two simple problems and to MATWS, a safety code for sodium cooled reactors. (authors)« less

Air transportation energy efficiency - Alternatives and implications

NASA Technical Reports Server (NTRS)

Williams, L. J.

1976-01-01

Results from recent studies of air transportation energy efficiency alternatives are discussed, along with some of the implications of these alternatives. The fuel-saving alternatives considered include aircraft operation, aircraft modification, derivative aircraft, and new aircraft. In the near-term, energy efficiency improvements should be possible through small improvements in fuel-saving flight procedures, higher density seating, and higher load factors. Additional small near-term improvements could be obtained through aircraft modifications, such as the relatively inexpensive drag reduction modifications. Derivatives of existing aircraft could meet the requirements for new aircraft and provide energy improvements until advanced technology is available to justify the cost of a completely new design. In order to obtain significant improvements in energy efficiency, new aircraft must truly exploit advanced technology in such areas as aerodynamics, composite structures, active controls, and advanced propulsion.

De Novo Design of Boron-Based Host Materials for Highly Efficient Blue and White Phosphorescent OLEDs with Low Efficiency Roll-Off.

PubMed

Xue, Miao-Miao; Huang, Chen-Chao; Yuan, Yi; Cui, Lin-Song; Li, Yong-Xi; Wang, Bo; Jiang, Zuo-Quan; Fung, Man-Keung; Liao, Liang-Sheng

2016-08-10

Borane is an excellent electron-accepting species, and its derivatives have been widely used in a variety of fields. However, the use of borane derivatives as host materials in OLEDs has rarely reported because the device performance is generally not satisfactory. In this work, two novel spiro-bipolar hosts with incorporated borane were designed and synthesized. The strategies used in preparing these materials were to increase the spatial separation of the highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) in the molecules, tune the connecting positions of functional groups, and incorporate specific functional groups with desirable thermal stability. Based on these designs, phosphorescent OLEDs with borane derivatives as hosts and with outstanding device performances were obtained. In particular, devices based on SAF-3-DMB/FIrpic exhibited an external quantum efficiency (EQE) of >25%. More encouragingly, the device was found to have quite a low efficiency roll-off, giving an efficiency of >20% even at a high brightness of 10000 cd/m(2). Furthermore, the EQE of the three-color-based (R + G + B) white OLED employing SAF-3-DMB as a host was also as high as 22.9% with CIE coordinates of (x, y) = (0.40, 0.48). At a brightness of 5000 cd/m(2), there was only a 3% decrease in EQE from its maximum value, implying a very low efficiency roll-off.

Deriving the Generalized Power and Efficiency Equations for Jet Propulsion Systems

NASA Astrophysics Data System (ADS)

Lee, Hsing-Juin; Chang, Chih-Luong

The kinetic power and efficiency equations for general jet propulsion systems are classically given in a much cursory, incomplete, and ununified format. This situation prohibits the propulsion designer from seeing the panorama of interrelated propulsion parameters and effects. And in some cases, it may lead to an energy-inefficient propulsion system design, or induce significant offset in propulsion performance as demonstrated in this study. Thus, herein we attempt to clarify some related concepts and to rigorously derive the associated generalized equations with a complete spectrum of physical parameters to be manipulated in quest of better performance. By a highly efficient interweaved transport scheme, we have derived the following equations for general jet propulsion systems: i.e., generalized total kinetic power, generalized kinetic power delivered to the jet propulsion system, generalized thrust power, generalized available propulsion power, and relevant generalized propulsive, thermal, and overall efficiency equations. Further, the variants of these equations under special conditions are also considered. For taking advantage of the above propulsion theories, we also illustrate some novel propulsion strategies in the final discussion, such as the dive-before-climb launch of rocket from highland mountain on eastbound rail, with perhaps minisatellites as the payloads.

Synergistic effect of iodide ions on the corrosion inhibition of steel in 0.5 M H 2SO 4 by new chalcone derivatives

NASA Astrophysics Data System (ADS)

Bouklah, M.; Hammouti, B.; Aouniti, A.; Benkaddour, M.; Bouyanzer, A.

2006-07-01

The effect of addition of 4',4-dihydroxychalcone (P 1), 4-aminochalcone (P 2) and 4-bromo, 4'-methoxychalcone (P 3) on the corrosion of steel in 0.5 M sulphuric acid has been studied by weight loss measurements, potentiodynamic and EIS measurements. We investigate the synergistic effect of iodide ions on the corrosion inhibition of steel in the presence of chalcone derivatives. The corrosion rates of the steel decrease with the increase of the chalcones concentration, while the inhibition efficiencies increase. The addition of iodide ions enhances the inhibition efficiency considerably. The presence of iodide ions increases the degree of surface coverage. The synergism parameters SΘ and SI, calculated from surface coverage and the values of inhibition efficiency, in the case of chalcone derivatives are found to be larger than unity. The enhanced inhibition efficiency in the presence of iodide ions is only due to synergism and there is a definite contribution from the inhibitors molecules. E (%) obtained from the various methods is in good agreement. Polarisation measurements show also that the compounds act as cathodic inhibitors.

Multi-disciplinary optimization of aeroservoelastic systems

NASA Technical Reports Server (NTRS)

Karpel, Mordechay

1990-01-01

Efficient analytical and computational tools for simultaneous optimal design of the structural and control components of aeroservoelastic systems are presented. The optimization objective is to achieve aircraft performance requirements and sufficient flutter and control stability margins with a minimal weight penalty and without violating the design constraints. Analytical sensitivity derivatives facilitate an efficient optimization process which allows a relatively large number of design variables. Standard finite element and unsteady aerodynamic routines are used to construct a modal data base. Minimum State aerodynamic approximations and dynamic residualization methods are used to construct a high accuracy, low order aeroservoelastic model. Sensitivity derivatives of flutter dynamic pressure, control stability margins and control effectiveness with respect to structural and control design variables are presented. The performance requirements are utilized by equality constraints which affect the sensitivity derivatives. A gradient-based optimization algorithm is used to minimize an overall cost function. A realistic numerical example of a composite wing with four controls is used to demonstrate the modeling technique, the optimization process, and their accuracy and efficiency.

Multidisciplinary optimization of aeroservoelastic systems using reduced-size models

NASA Technical Reports Server (NTRS)

Karpel, Mordechay

1992-01-01

Efficient analytical and computational tools for simultaneous optimal design of the structural and control components of aeroservoelastic systems are presented. The optimization objective is to achieve aircraft performance requirements and sufficient flutter and control stability margins with a minimal weight penalty and without violating the design constraints. Analytical sensitivity derivatives facilitate an efficient optimization process which allows a relatively large number of design variables. Standard finite element and unsteady aerodynamic routines are used to construct a modal data base. Minimum State aerodynamic approximations and dynamic residualization methods are used to construct a high accuracy, low order aeroservoelastic model. Sensitivity derivatives of flutter dynamic pressure, control stability margins and control effectiveness with respect to structural and control design variables are presented. The performance requirements are utilized by equality constraints which affect the sensitivity derivatives. A gradient-based optimization algorithm is used to minimize an overall cost function. A realistic numerical example of a composite wing with four controls is used to demonstrate the modeling technique, the optimization process, and their accuracy and efficiency.

Efficient myogenic differentiation of human adipose-derived stem cells by the transduction of engineered MyoD protein

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

Sung, Min Sun; Biosystems and Bioengineering Program, University of Science and Technology; Mun, Ji-Young

2013-07-19

Highlights: •MyoD was engineered to contain protein transduction domain and endosome-disruptive INF7 peptide. •The engineered MyoD-IT showed efficient nuclear targeting through an endosomal escape by INF7 peptide. •By applying MyoD-IT, human adipose-derived stem cells (hASCs) were differentiated into myogenic cells. •hASCs differentiated by applying MyoD-IT fused to myotubes through co-culturing with mouse myoblasts. •Myogenic differentiation using MyoD-IT is a safe method without the concern of altering the genome. -- Abstract: Human adipose-derived stem cells (hASCs) have great potential as cell sources for the treatment of muscle disorders. To provide a safe method for the myogenic differentiation of hASCs, we engineeredmore » the MyoD protein, a key transcription factor for myogenesis. The engineered MyoD (MyoD-IT) was designed to contain the TAT protein transduction domain for cell penetration and the membrane-disrupting INF7 peptide, which is an improved version of the HA2 peptide derived from influenza. MyoD-IT showed greatly improved nuclear targeting ability through an efficient endosomal escape induced by the pH-sensitive membrane disruption of the INF7 peptide. By applying MyoD-IT to a culture, hASCs were efficiently differentiated into long spindle-shaped myogenic cells expressing myosin heavy chains. Moreover, these cells differentiated by an application of MyoD-IT fused to myotubes with high efficiency through co-culturing with mouse C2C12 myoblasts. Because internalized proteins can be degraded in cells without altering the genome, the myogenic differentiation of hASCs using MyoD-IT would be a safe and clinically applicable method.« less

An efficient chemical synthesis of nicotinamide riboside (NAR) and analogues.

PubMed

Tanimori, Shinji; Ohta, Takeshi; Kirihata, Mitsunori

2002-04-22

A simple and efficient synthesis of nicotinamide riboside (NAR) 1 and derivatives 4 and 5 via trimethylsilyl trifluoromethanesulfonate (TMSOTf)-mediated N-glycosilation followed by spontaneous deacetylation by treating with methanol is reported.

Eigenvalue sensitivity analysis of planar frames with variable joint and support locations

NASA Technical Reports Server (NTRS)

Chuang, Ching H.; Hou, Gene J. W.

1991-01-01

Two sensitivity equations are derived in this study based upon the continuum approach for eigenvalue sensitivity analysis of planar frame structures with variable joint and support locations. A variational form of an eigenvalue equation is first derived in which all of the quantities are expressed in the local coordinate system attached to each member. Material derivative of this variational equation is then sought to account for changes in member's length and orientation resulting form the perturbation of joint and support locations. Finally, eigenvalue sensitivity equations are formulated in either domain quantities (by the domain method) or boundary quantities (by the boundary method). It is concluded that the sensitivity equation derived by the boundary method is more efficient in computation but less accurate than that of the domain method. Nevertheless, both of them in terms of computational efficiency are superior to the conventional direct differentiation method and the finite difference method.

The Size Distribution of Near-Earth Objects Larger Than 10 m

NASA Astrophysics Data System (ADS)

Trilling, D. E.; Valdes, F.; Allen, L.; James, D.; Fuentes, C.; Herrera, D.; Axelrod, T.; Rajagopal, J.

2017-10-01

We analyzed data from the first year of a survey for Near-Earth Objects (NEOs) that we are carrying out with the Dark Energy Camera (DECam) on the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory. We implanted synthetic NEOs into the data stream to derive our nightly detection efficiency as a function of magnitude and rate of motion. Using these measured efficiencies and the solar system absolute magnitudes derived by the Minor Planet Center for the 1377 measurements of 235 unique NEOs detected, we directly derive, for the first time from a single observational data set, the NEO size distribution from 1 km down to 10 m. We find that there are {10}6.6 NEOs larger than 10 m. This result implies a factor of 10 fewer small NEOs than some previous results, though our derived size distribution is in good agreement with several other estimates.

Chemoenzymatic synthesis of new derivatives of glycyrrhetinic acid with antiviral activity. Molecular docking study.

PubMed

Zígolo, M Antonela; Salinas, Maximiliano; Alché, Laura; Baldessari, Alicia; Liñares, Guadalupe García

2018-08-01

We present an efficient approach to the synthesis of a series of glycyrrhetinic acid derivatives. Six derivatives, five of them new compounds, were obtained through chemoenzymatic reactions in very good to excellent yield. In order to find the optimal reaction conditions, the influence of various parameters such as enzyme source, nucleophile:substrate ratio, enzyme:substrate ratio, solvent and temperature was studied. The excellent results obtained by lipase catalysis made the procedure very efficient considering their advantages such as mild reaction conditions and low environmental impact. Moreover, in order to explain the reactivity of glycyrrhetinic acid and the acetylated derivative to different nucleophiles in the enzymatic reactions, molecular docking studies were carried out. In addition, one of the synthesized compounds exhibited remarkable antiviral activity against TK + and TK- strains of Herpes simplex virus type 1 (HSV-1), sensitive and resistant to acyclovir (ACV) treatment. Copyright © 2018 Elsevier Inc. All rights reserved.

86% internal differential efficiency from 8 to 9 µm-emitting, step-taper active-region quantum cascade lasers.

PubMed

Kirch, Jeremy D; Chang, Chun-Chieh; Boyle, Colin; Mawst, Luke J; Lindberg, Don; Earles, Tom; Botez, Dan

2016-10-17

8.4 μm-emitting quantum cascade lasers (QCLs) have been designed to have, right from threshold, both carrier-leakage suppression and miniband-like carrier extraction. The slope-efficiency characteristic temperature T₁, the signature of carrier-leakage suppression, is found to be 665 K. Resonant-tunneling carrier extraction from both the lower laser level (ll) and the level below it, coupled with highly effective ll-depopulation provide a very short ll lifetime (~0.12 ps). As a result the laser-transition differential efficiency reaches 89%, and the internal differential efficiency η_id, derived from a variable mirror-loss study, is found to be 86%, in good agreement with theory. A study of 8.8 μm-emitting QCLs also provides an η_id value of 86%. A corrected equation for the external differential efficiency is derived which leads to a fundamental limit of ~90% for the η_id values of mid-infrared QCLs. In turn, the fundamental wallplug-efficiency limits become ~34% higher than previously predicted.

Synthesis of 8-Aryl-O-methylcyanidins and Their Usage for Dye-Sensitized Solar Cell Devices.

PubMed

Kimura, Yuki; Oyama, Kin-Ichi; Murata, Yasujiro; Wakamiya, Atsushi; Yoshida, Kumi

2017-02-16

Anthocyanins as natural pigments are colorful and environmentally compatible dyes for dye-sensitized solar cells (DSSCs). To increase the efficiency, we designed and synthesized unnatural O -methylflavonols and O -methylcyanidins that possess an aryl group at the 8-position. We synthesized per - O -methylquercetin from quercetin, then using selective demethylation prepared various O -methylquercetins. Using the Suzuki-Miyaura coupling reaction, 8-arylation of per - O -methylquercetin was achieved. Using a LiAlH₄ reduction or Clemmensen reduction, these flavonols were transformed to the corresponding cyanidin derivatives in satisfactory yields. Using these dyes, we fabricated DSSCs, and their efficiency was investigated. The efficiency of tetra - O -methylflavonol was 0.31%. However, the introduction of the 8-aryl residue increased the efficiency to 1.04%. In comparison to these flavonols, O -methylcyanidins exhibited a lower efficiency of 0.05% to 0.52%. The introduction of the 8-aryl group into the cyanidin derivatives did not result in a remarkable increase in the efficiency. These phenomena may be due to the poor fit of the HOMO-LUMO level of the dyes to the TiO₂ conduction band.

Enhancing cadmium bioremediation by a complex of water-hyacinth derived pellets immobilized with Chlorella sp.

PubMed

Shen, Ying; Zhu, Wenzhe; Li, Huan; Ho, Shih-Hsin; Chen, Jianfeng; Xie, Youping; Shi, Xinguo

2018-06-01

A complex of water-hyacinth derived pellets immobilized with Chlorella sp. was applied, for the first time, in the bioremediation of Cadmium (Cd). The Cd(II) removal efficiency of the complex was optimized by investigating several parameters, including the pellet materials, algal culture age, and light intensity. Results showed that the Cd(II) removal efficiency was positively related to the algal immobilization efficiency and the algal bioaccumulation capacity. Since higher surface hydrophilicity leads to higher immobilization efficiency, the water-hyacinth leaf biochar pellet (WLBp) was selected as the optimal carrier. A maximum Cd(II) removal efficiency of 92.45% was obtained by the complex of WLBp immobilized with algal cells in stationary growth phase and illuminated with a light intensity of 119 μmol m -2  s -1 . Recovery tests on both microalgal cells and the WLBp demonstrated that the algal cells and the biochar pellet can be economically recycled and reused. Copyright © 2018 Elsevier Ltd. All rights reserved.

Efficient generation of integration-free human induced pluripotent stem cells from keratinocytes by simple transfection of episomal vectors.

PubMed

Piao, Yulan; Hung, Sandy Shen-Chi; Lim, Shiang Y; Wong, Raymond Ching-Bong; Ko, Minoru S H

2014-07-01

Keratinocytes represent an easily accessible cell source for derivation of human induced pluripotent stem (hiPS) cells, reportedly achieving higher reprogramming efficiency than fibroblasts. However, most studies utilized a retroviral or lentiviral method for reprogramming of keratinocytes, which introduces undesirable transgene integrations into the host genome. Moreover, current protocols of generating integration-free hiPS cells from keratinocytes are mostly inefficient. In this paper, we describe a more efficient, simple-to-use, and cost-effective method for generating integration-free hiPS cells from keratinocytes. Our improved method using lipid-mediated transfection achieved a reprogramming efficiency of ∼0.14% on average. Keratinocyte-derived hiPS cells showed no integration of episomal vectors, expressed stem cell-specific markers and possessed potentials to differentiate into all three germ layers by in vitro embryoid body formation as well as in vivo teratoma formation. To our knowledge, this represents the most efficient method to generate integration-free hiPS cells from keratinocytes. ©AlphaMed Press.

Potential natural sensitizers extracted from the skin of Canarium odontophyllum fruits for dye-sensitized solar cells.

PubMed

Lim, Andery; Kumara, N T R N; Tan, Ai Ling; Mirza, Aminul Huq; Chandrakanthi, R L N; Petra, Mohammad Iskandar; Ming, Lim Chee; Senadeera, G K R; Ekanayake, Piyasiri

2015-03-05

Possibility of use of dye extract from skin samples of a seasonal, indigenous fruit from Borneo, namely Canarium odontophyllum, in dye sensitized solar cells (DSSCs) are explored. Three main groups of flavonoid pigments are detected and these pigments exhibit different UV-vis absorption properties, and hence showing different light harvesting capabilities. When applied in DSSCs. The detected pigment constituents of the extract consist of aurone (maritimein), anthocyanidin (pelargonidin) and anthocyanidin (cyanidin derivatives). When tested in DSSC, the highest conversion efficiency of 1.43% is exhibited by cyanidin derivatives, and this is followed by conversion efficiencies of 0.51% and 0.79% for aurone and pelargonidin, respectively. It is shown that individual pigments, like cyanidin derivatives and pelargonidin, exhibit higher power conversion efficiency when compared to that of C.odontophyllum skin pigment mixture (with a conversion efficiency of only 0.68%). The results indicate a possibility of masking effects of the pigments when used as a mixture. The acidification of C.odontophyllum skin pigments with concentrated hydrochloric acid improves the conversion efficiency of the mixture from 0.68% to 0.99%. The discussion in this paper will draw data and observations from the variation in absorption and adsorption properties, the HOMO-LUMO levels, the energy band gaps and the functional group compositions of the detected flavonoids. Copyright © 2014 Elsevier B.V. All rights reserved.

Efficiency and its bounds for thermal engines at maximum power using Newton's law of cooling.

PubMed

Yan, H; Guo, Hao

2012-01-01

We study a thermal engine model for which Newton's cooling law is obeyed during heat transfer processes. The thermal efficiency and its bounds at maximum output power are derived and discussed. This model, though quite simple, can be applied not only to Carnot engines but also to four other types of engines. For the long thermal contact time limit, new bounds, tighter than what were known before, are obtained. In this case, this model can simulate Otto, Joule-Brayton, Diesel, and Atkinson engines. While in the short contact time limit, which corresponds to the Carnot cycle, the same efficiency bounds as that from Esposito et al. [Phys. Rev. Lett. 105, 150603 (2010)] are derived. In both cases, the thermal efficiency decreases as the ratio between the heat capacities of the working medium during heating and cooling stages increases. This might provide instructions for designing real engines. © 2012 American Physical Society

Electrochemical synthesis of azanucleoside derivatives using a lithium perchlorate-nitromethane system.

PubMed

Kim, Shokaku; Shoji, Takao; Kitano, Yoshikazu; Chiba, Kazuhiro

2013-07-25

We have developed a highly efficient synthetic method for azanucleosides using a lithium perchlorate-nitromethane reaction medium, allowing direct and exclusive installation of various nucleophiles, including protected nucleobases into prolinol derivatives at the preferred 5-position.

Directed evolution and expression tuning of geraniol synthase for efficient geraniol production in Escherichia coli.

PubMed

Tashiro, Miki; Fujii, Akira; Kawai-Noma, Shigeko; Saito, Kyoichi; Umeno, Daisuke

2017-11-17

To achieve an efficient production of geraniol and its derivatives in Escherichia coli, we aimed to improve the activity of geraniol synthase (GES) through a single round of mutagenesis and screening for higher substrate consumption. We isolated GES variants that outperform their parent in geraniol production. The analysis of GES variants indicated that the expression level of GES was the bottleneck for geraniol synthesis. Over-expression of the mutant GES M53 with a 5'-untranslated sequence designed for high translational efficiency, along with the additional expression of mevalonate pathway enzymes, isopentenyl pyrophosphate isomerase, and geranyl pyrophosphate synthase, yielded 300 mg/L/12 h geraniol and its derivatives (>1000 mg/L/42 h in total) in a shaking flask.

Commercial Cargo Derivative Study of the Advanced Hybrid Wing Body Configuration with Over-Wing Engine Nacelles

NASA Technical Reports Server (NTRS)

Hooker, John R.; Wick, Andrew T.; Hardin, Christopher J.

2017-01-01

LM has leveraged our partnership with the Air Force Research Laboratory (AFRL) and NASA on the advanced hybrid wing body (HWB) concept to develop a commercial freighter which addresses the NASA Advanced Air Transport Technology (AATT) Project goals for improved efficiency beyond 2025. The current Air Force Research Laboratory (AFRL) Revolutionary Configurations for Energy Efficiency (RCEE) program established the HWB configuration and technologies needed for military transports to achieve aerodynamic and fuel efficiencies well beyond the commercial industry's most modern designs. This study builds upon that effort to develop a baseline commercial cargo aircraft and two HWB derivative commercial cargo aircraft to quanitify the benefit of the HWB and establish a technology roadmap for further development.

A decoupled recursive approach for constrained flexible multibody system dynamics

NASA Technical Reports Server (NTRS)

Lai, Hao-Jan; Kim, Sung-Soo; Haug, Edward J.; Bae, Dae-Sung

1989-01-01

A variational-vector calculus approach is employed to derive a recursive formulation for dynamic analysis of flexible multibody systems. Kinematic relationships for adjacent flexible bodies are derived in a companion paper, using a state vector notation that represents translational and rotational components simultaneously. Cartesian generalized coordinates are assigned for all body and joint reference frames, to explicitly formulate deformation kinematics under small deformation kinematics and an efficient flexible dynamics recursive algorithm is developed. Dynamic analysis of a closed loop robot is performed to illustrate efficiency of the algorithm.

Exergy Analysis of Rocket Systems

NASA Technical Reports Server (NTRS)

Gilbert, Andrew; Mesmer, Bryan; Watson, Michael D.

2015-01-01

Exergy is defined as the useful work available from a system in a specified environment. Exergy analysis allows for comparison between different system designs, and allows for comparison of subsystem efficiencies within system designs. The proposed paper explores the relationship between the fundamental rocket equation and an exergy balance equation. A previously derived exergy equation related to rocket systems is investigated, and a higher fidelity analysis will be derived. The exergy assessments will enable informed, value-based decision making when comparing alternative rocket system designs, and will allow the most efficient configuration among candidate configurations to be determined.

Titanium isopropoxide as efficient catalyst for the aza-Baylis-Hillman reaction. Selective formation of alpha-methylene-beta-amino acid derivatives.

PubMed

Balan, Daniela; Adolfsson, Hans

2002-04-05

The direct formation of alpha-methylene-beta-amino acid derivatives is achieved using the aza version of the Baylis-Hillman protocol. The products are readily formed in a three-component one-pot reaction between arylaldehydes, sulfonamides, and alpha,beta-unsaturated carbonyl compounds. The reaction is efficiently catalyzed by titanium isopropoxide and 2-hydroxyquinuclidine in the presence of molecular sieves. The protocol allows for structural variation of the substrates, tolerating electron-poor and electron-rich arylaldehydes and various Michael acceptors.

Improved cell therapy protocol for Parkinson’s disease based on differentiation efficiency and safety of hESC-, hiPSC and non-human primate iPSC-derived DA neurons

PubMed Central

Maria, Sundberg; Helle, Bogetofte; Tristan, Lawson; Gaynor, Smith; Arnar, Astradsson; Michele, Moore; Teresia, Osborn; Oliver, Cooper; Roger, Spealman; Penelope, Hallett; Ole, Isacson

2013-01-01

The main motor symptoms of Parkinson’s disease are due to the loss of dopaminergic (DA) neurons in the ventral midbrain (VM). For the future treatment of Parkinson’s disease with cell transplantation it is important to develop efficient differentiation methods for production of human iPSCs and hESCs-derived midbrain-type DA neurons. Here we describe an efficient differentiation and sorting strategy for DA-neurons from both human ES/iPS cells and non-human primate iPSCs. The use of non-human primate iPSCs for neuronal differentiation and autologous transplantation is important for pre-clinical evaluation of safety and efficacy of stem cell-derived DA neurons. The aim of this study was to improve the safety of human- and non-human primate-iPSC (PiPSC)-derived DA neurons. According to our results, NCAM+/CD29low sorting enriched VM DA-neurons from pluripotent stem cell-derived neural cell populations. NCAM+/CD29low DA-neurons were positive for FOXA2/TH and EN1/TH and this cell population had increased expression levels of FOXA2, LMX1A, TH, GIRK2, PITX3, EN1, NURR1 mRNA compared to unsorted neural cell populations. PiPSC-derived NCAM+/CD29low DA-neurons were able to restore motor function of 6-OHDA lesioned rats 16 weeks after transplantation. The transplanted sorted cells also integrated in the rodent brain tissue, with robust TH+/hNCAM+ neuritic innervation of the host striatum. One year after autologous transplantation, the primate iPSC-derived neural cells survived in the striatum of one primate without any immunosuppression. These neural cell grafts contained FOXA2/TH-positive neurons in the graft site. This is an important proof of concept for the feasibility and safety of iPSC-derived cell transplantation therapies in the future. PMID:23666606

Computationally efficient multibody simulations

NASA Technical Reports Server (NTRS)

Ramakrishnan, Jayant; Kumar, Manoj

1994-01-01

Computationally efficient approaches to the solution of the dynamics of multibody systems are presented in this work. The computational efficiency is derived from both the algorithmic and implementational standpoint. Order(n) approaches provide a new formulation of the equations of motion eliminating the assembly and numerical inversion of a system mass matrix as required by conventional algorithms. Computational efficiency is also gained in the implementation phase by the symbolic processing and parallel implementation of these equations. Comparison of this algorithm with existing multibody simulation programs illustrates the increased computational efficiency.

Regioselective 5-exo-dig oxy-cyclization of 2-alkynylbenzamide for the synthesis of isobenzofuran-1-imines and isobenzofuran.

PubMed

Wang, Rui-Xiang; Yuan, Si-Tian; Liu, Jin-Biao; Wu, Jie; Qiu, Guanyinsheng

2018-06-06

A TBAB-mediated brominative 5-exo-dig oxy-cyclization of 2-alkynylbenzamide is described here for the synthesis of isobenzofuran-1-imines and isobenzofuran derivatives at room temperature with a high efficiency and a broad reaction scope. The resulting isobenzofuran derivatives are also applied for synthesising various substituted isobenzofuran derivatives.

Optimization of Turbine Engine Cycle Analysis with Analytic Derivatives

NASA Technical Reports Server (NTRS)

Hearn, Tristan; Hendricks, Eric; Chin, Jeffrey; Gray, Justin; Moore, Kenneth T.

2016-01-01

A new engine cycle analysis tool, called Pycycle, was built using the OpenMDAO framework. Pycycle provides analytic derivatives allowing for an efficient use of gradient-based optimization methods on engine cycle models, without requiring the use of finite difference derivative approximation methods. To demonstrate this, a gradient-based design optimization was performed on a turbofan engine model. Results demonstrate very favorable performance compared to an optimization of an identical model using finite-difference approximated derivatives.

Novel Water Soluble Chitosan Derivatives with 1,2,3-Triazolium and Their Free Radical-Scavenging Activity

PubMed Central

Li, Qing; Sun, Xueqi; Gu, Guodong

2018-01-01

Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium charged units by associating “click reaction” with efficient 1,2,3-triazole quaternization were designed and synthesized. Their free radical-scavenging activity against three free radicals was tested. The inhibitory property and water solubility of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. It is hypothesized that triazole or triazolium groups enable the synthesized chitosan to possess obviously better radical-scavenging activity. Moreover, the scavenging activity against superoxide radical of chitosan derivatives with triazolium (IC50 < 0.01 mg mL−1) was more efficient than that of derivatives with triazole and Vitamin C. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical-scavenging assay, the same pattern were observed, which should be related to the triazolium grafted at the periphery of molecular chains. PMID:29597269

Novel Water Soluble Chitosan Derivatives with 1,2,3-Triazolium and Their Free Radical-Scavenging Activity.

PubMed

Li, Qing; Sun, Xueqi; Gu, Guodong; Guo, Zhanyong

2018-03-28

Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium charged units by associating "click reaction" with efficient 1,2,3-triazole quaternization were designed and synthesized. Their free radical-scavenging activity against three free radicals was tested. The inhibitory property and water solubility of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. It is hypothesized that triazole or triazolium groups enable the synthesized chitosan to possess obviously better radical-scavenging activity. Moreover, the scavenging activity against superoxide radical of chitosan derivatives with triazolium (IC 50 < 0.01 mg mL -1 ) was more efficient than that of derivatives with triazole and Vitamin C. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical-scavenging assay, the same pattern were observed, which should be related to the triazolium grafted at the periphery of molecular chains.

Morphology Control for Fully Printable Organic-Inorganic Bulk-heterojunction Solar Cells Based on a Ti-alkoxide and Semiconducting Polymer.

PubMed

Kato, Takehito; Oinuma, Chihiro; Otsuka, Munechika; Hagiwara, Naoki

2017-01-10

The photoactive layer of a typical organic thin-film bulk-heterojunction (BHJ) solar cell commonly uses fullerene derivatives as the electron-accepting material. However, fullerene derivatives are air-sensitive; therefore, air-stable material is needed as an alternative. In the present study, we propose and describe the properties of Ti-alkoxide as an alternative electron-accepting material to fullerene derivatives to create highly air-stable BHJ solar cells. It is well-known that controlling the morphology in the photoactive layer, which is constructed with fullerene derivatives as the electron acceptor, is important for obtaining a high overall efficiency through the solvent method. The conventional solvent method is useful for high-solubility materials, such as fullerene derivatives. However, for Ti-alkoxides, the conventional solvent method is insufficient, because they only dissolve in specific solvents. Here, we demonstrate a new approach to morphology control that uses the molecular bulkiness of Ti-alkoxides without the conventional solvent method. That is, this method is one approach to obtain highly efficient, air-stable, organic-inorganic bulk-heterojunction solar cells.

A Selective Organic-Based Corrosion Inhibitors Containing Iodide Ion as Enhancer for Protection of Carbon Steel: A Review

NASA Astrophysics Data System (ADS)

Ibrahim, I. M.; Kassim, E. S. Mohd; Husin, H.; Jai, J.; Daud, M.; Hashim, M. A.

2018-05-01

This paper contains a review on the effect of halide ion with a selected inhibitor which is imidazole derivatives on the efficiency of corrosion inhibition. The paper first describes the mechanism of synergistic inhibition effect among halide ions enhancer with inhibitor on the steel surface. Then the paper describes the measured inhibition efficiency and summarizes the synergistic inhibition condition of imidazoline derivatives inhibitor with iodide ions. The characteristic of synergistic inhibition effect and the relationship between the amount of iodide ion consumption and the amount of organic inhibitor consumption are also discussed. It has been shown that, the synergistic effect between imidazole derivative and iodide ion is an effective method to improve the inhibitive performance in different aqueous media.

Horseradish-Peroxidase-Catalyzed Tyrosine Click Reaction.

PubMed

Sato, Shinichi; Nakamura, Kosuke; Nakamura, Hiroyuki

2017-03-02

The efficiency of protein chemical modification on tyrosine residues with N-methylluminol derivatives was drastically improved by using horseradish peroxidase (HRP). In the previous method, based on the use of hemin and H 2 O 2 , oxidative side reactions such as cysteine oxidation were problematic for functionalization of proteins selectively on tyrosine residues. Oxidative activation of N-methylluminol derivatives with a minimum amount of H 2 O 2 prevented the occurrence of oxidative side reactions under HRP-catalyzed conditions. As probes for HRP-catalyzed protein modification, N-methylluminol derivatives showed much higher efficiency than tyramide without inducing oligomerization of probe molecules. Tyrosine modification also proceeded in the presence of β-nicotinamide adenine dinucleotide (NADH, H 2 O 2 -free conditions). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Copper-catalyzed aerobic oxidative C-H functionalization of substituted pyridines: synthesis of imidazopyridine derivatives.

PubMed

Yu, Jipan; Jin, Yunhe; Zhang, Hao; Yang, Xiaobo; Fu, Hua

2013-12-02

A novel, efficient, and practical method for the synthesis of imidazopyridine derivatives has been developed through the copper-catalyzed aerobic oxidative C-H functionalization of substituted pyridines with N-(alkylidene)-4H-1,2,4-triazol-4-amines. The procedure occurs by cleavage of the N-N bond in the N-(alkylidene)-4H-1,2,4-triazol-4-amines and activation of an aryl C-H bond in the substituted pyridines. This is the first example of the preparation of imidazopyridine derivatives by using pyridines as the substrates by transition-metal-catalyzed C-H functionalization. This method should provide a novel and efficient strategy for the synthesis of other nitrogen heterocycles. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Epileptic seizures as condensed sleep: an analysis of network dynamics from electroencephalogram signals.

PubMed

Gast, Heidemarie; Müller, Markus; Rummel, Christian; Roth, Corinne; Mathis, Johannes; Schindler, Kaspar; Bassetti, Claudio L

2014-06-01

Both deepening sleep and evolving epileptic seizures are associated with increasing slow-wave activity. Larger-scale functional networks derived from electroencephalogram indicate that in both transitions dramatic changes of communication between brain areas occur. During seizures these changes seem to be 'condensed', because they evolve more rapidly than during deepening sleep. Here we set out to assess quantitatively functional network dynamics derived from electroencephalogram signals during seizures and normal sleep. Functional networks were derived from electroencephalogram signals from wakefulness, light and deep sleep of 12 volunteers, and from pre-seizure, seizure and post-seizure time periods of 10 patients suffering from focal onset pharmaco-resistant epilepsy. Nodes of the functional network represented electrical signals recorded by single electrodes and were linked if there was non-random cross-correlation between the two corresponding electroencephalogram signals. Network dynamics were then characterized by the evolution of global efficiency, which measures ease of information transmission. Global efficiency was compared with relative delta power. Global efficiency significantly decreased both between light and deep sleep, and between pre-seizure, seizure and post-seizure time periods. The decrease of global efficiency was due to a loss of functional links. While global efficiency decreased significantly, relative delta power increased except between the time periods wakefulness and light sleep, and pre-seizure and seizure. Our results demonstrate that both epileptic seizures and deepening sleep are characterized by dramatic fragmentation of larger-scale functional networks, and further support the similarities between sleep and seizures. © 2013 European Sleep Research Society.

On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

DOE PAGES

Kovilakam, Mahesh; Deshler, Terry

2015-08-26

In situ stratospheric aerosol measurements, from University of Wyoming optical particle counters (OPCs), are compared with Stratospheric Aerosol Gas Experiment (SAGE) II (versions 6.2 and 7.0) and Halogen Occultation Experiment (HALOE) satellite measurements to investigate differences between SAGE II/HALOE-measured extinction and derived surface area and OPC-derived extinction and surface area. Coincident OPC and SAGE II measurements are compared for a volcanic (1991-1996) and nonvolcanic (1997-2005) period. OPC calculated extinctions agree with SAGE II measurements, within instrumental uncertainty, during the volcanic period, but have been a factor of 2 low during the nonvolcanic period. Three systematic errors associated with the OPCmore » measurements, anisokineticity, inlet particle evaporation, and counting efficiency, were investigated. An overestimation of the OPC counting efficiency is found to be the major source of systematic error. With this correction OPC calculated extinction increases by 15-30% (30-50%) for the volcanic (nonvolcanic) measurements. These changes significantly improve the comparison with SAGE II and HALOE extinctions in the nonvolcanic cases but slightly degrade the agreement in the volcanic period. These corrections have impacts on OPC-derived surface area density, exacerbating the poor agreement between OPC and SAGE II (version 6.2) surface areas. Furthermore, this disparity is reconciled with SAGE II version 7.0 surface areas. For both the volcanic and nonvolcanic cases these changes in OPC counting efficiency and in the operational SAGE II surface area algorithm leave the derived surface areas from both platforms in significantly better agreement and within the ± 40% precision of the OPC moment calculations.« less

On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

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

Kovilakam, Mahesh; Deshler, Terry

In situ stratospheric aerosol measurements, from University of Wyoming optical particle counters (OPCs), are compared with Stratospheric Aerosol Gas Experiment (SAGE) II (versions 6.2 and 7.0) and Halogen Occultation Experiment (HALOE) satellite measurements to investigate differences between SAGE II/HALOE-measured extinction and derived surface area and OPC-derived extinction and surface area. Coincident OPC and SAGE II measurements are compared for a volcanic (1991-1996) and nonvolcanic (1997-2005) period. OPC calculated extinctions agree with SAGE II measurements, within instrumental uncertainty, during the volcanic period, but have been a factor of 2 low during the nonvolcanic period. Three systematic errors associated with the OPCmore » measurements, anisokineticity, inlet particle evaporation, and counting efficiency, were investigated. An overestimation of the OPC counting efficiency is found to be the major source of systematic error. With this correction OPC calculated extinction increases by 15-30% (30-50%) for the volcanic (nonvolcanic) measurements. These changes significantly improve the comparison with SAGE II and HALOE extinctions in the nonvolcanic cases but slightly degrade the agreement in the volcanic period. These corrections have impacts on OPC-derived surface area density, exacerbating the poor agreement between OPC and SAGE II (version 6.2) surface areas. Furthermore, this disparity is reconciled with SAGE II version 7.0 surface areas. For both the volcanic and nonvolcanic cases these changes in OPC counting efficiency and in the operational SAGE II surface area algorithm leave the derived surface areas from both platforms in significantly better agreement and within the ± 40% precision of the OPC moment calculations.« less

Updating the limit efficiency of silicon solar cells

NASA Technical Reports Server (NTRS)

Wolf, M.

1979-01-01

Evaluation of the limit efficiency based on the simplest, most basic mathematical method that is appropriate for the conditions imposed by the cell model is discussed. The methodology, the solar cell structure, and the selection of the material parameters used in the evaluation are described. The results are discussed including a set of design goals derived from the limit efficiency.

Heterodyne efficiency of a coherent free-space optical communication model through atmospheric turbulence.

PubMed

Ren, Yongxiong; Dang, Anhong; Liu, Ling; Guo, Hong

2012-10-20

The heterodyne efficiency of a coherent free-space optical (FSO) communication model under the effects of atmospheric turbulence and misalignment is studied in this paper. To be more general, both the transmitted beam and local oscillator beam are assumed to be partially coherent based on the Gaussian Schell model (GSM). By using the derived analytical form of the cross-spectral function of a GSM beam propagating through atmospheric turbulence, a closed-form expression of heterodyne efficiency is derived, assuming that the propagation directions for the transmitted and local oscillator beams are slightly different. Then the impacts of atmospheric turbulence, configuration of the two beams (namely, beam radius and spatial coherence width), detector radius, and misalignment angle over heterodyne efficiency are examined. Numerical results suggest that the beam radius of the two overlapping beams can be optimized to achieve a maximum heterodyne efficiency according to the turbulence conditions and the detector radius. It is also found that atmospheric turbulence conditions will significantly degrade the efficiency of heterodyne detection, and compared to fully coherent beams, partially coherent beams are less sensitive to the changes in turbulence conditions and more robust against misalignment at the receiver.

Synthesis of 8-Aryl-O-methylcyanidins and Their Usage for Dye-Sensitized Solar Cell Devices

PubMed Central

Kimura, Yuki; Oyama, Kin-ichi; Murata, Yasujiro; Wakamiya, Atsushi; Yoshida, Kumi

2017-01-01

Anthocyanins as natural pigments are colorful and environmentally compatible dyes for dye-sensitized solar cells (DSSCs). To increase the efficiency, we designed and synthesized unnatural O-methylflavonols and O-methylcyanidins that possess an aryl group at the 8-position. We synthesized per-O-methylquercetin from quercetin, then using selective demethylation prepared various O-methylquercetins. Using the Suzuki-Miyaura coupling reaction, 8-arylation of per-O-methylquercetin was achieved. Using a LiAlH4 reduction or Clemmensen reduction, these flavonols were transformed to the corresponding cyanidin derivatives in satisfactory yields. Using these dyes, we fabricated DSSCs, and their efficiency was investigated. The efficiency of tetra-O-methylflavonol was 0.31%. However, the introduction of the 8-aryl residue increased the efficiency to 1.04%. In comparison to these flavonols, O-methylcyanidins exhibited a lower efficiency of 0.05% to 0.52%. The introduction of the 8-aryl group into the cyanidin derivatives did not result in a remarkable increase in the efficiency. These phenomena may be due to the poor fit of the HOMO-LUMO level of the dyes to the TiO2 conduction band. PMID:28212330

Thrust and efficiency model for electron-driven magnetic nozzles

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

Little, Justin M.; Choueiri, Edgar Y.

2013-10-15

A performance model is presented for magnetic nozzle plasmas driven by electron thermal expansion to investigate how the thrust coefficient and beam divergence efficiency scale with the incoming plasma flow and magnetic field geometry. Using a transformation from cylindrical to magnetic coordinates, an approximate analytical solution is derived to the axisymmetric two-fluid equations for a collisionless plasma flow along an applied magnetic field. This solution yields an expression for the half-width at half-maximum of the plasma density profile in the far-downstream region, from which simple scaling relations for the thrust coefficient and beam divergence efficiency are derived. It is foundmore » that the beam divergence efficiency is most sensitive to the density profile of the flow into the nozzle throat, with the highest efficiencies occurring for plasmas concentrated along the nozzle axis. Increasing the expansion ratio of the magnetic field leads to efficiency improvements that are more pronounced for incoming plasmas that are not concentrated along the axis. This implies that the additional magnet required to increase the expansion ratio may be worth the added complexity for plasma sources that exhibit poor confinement.« less

The troika of business cycle, efficiency and volatility. An East Asian perspective

NASA Astrophysics Data System (ADS)

Arshad, Shaista; Rizvi, Syed Aun R.

2015-02-01

The EMH has been the subject of much debate over the past few decades, with a recent surge in interest in Asian markets. Asian markets which traditionally comprise of many emerging markets are more volatile and speculative in nature. The heart of our study focuses on the East Asian economies, which have experienced massive capital inflows. This begs the question of whether or not the stock markets are efficient enough for further investment and development. Our paper differs from existing literature as it focuses on deriving weak form efficiency rankings during different business cycle phases. We endeavour further to assess the volatility and business cycle phases. Taking Malaysia, Indonesia, Singapore and South Korea owing to their economic and financial development, we use MF-DFA to derive efficiency rankings and find firstly, the overall efficiency has improved over the past two decades and secondly, markets are more efficient in growth phases in comparison to its preceding decline. Similarly, employing wavelet decomposition in conjunction with EGARCH, we obtain volatility of stock markets in two distinct time horizons, i.e. short term and long term. We find the markets to be more stable during economic boom than its preceding bust. Our results confer with mainstream literature.

Polydopamine-mediated surface modification of scaffold materials for human neural stem cell engineering.

PubMed

Yang, Kisuk; Lee, Jung Seung; Kim, Jin; Lee, Yu Bin; Shin, Heungsoo; Um, Soong Ho; Kim, Jeong Beom; Park, Kook In; Lee, Haeshin; Cho, Seung-Woo

2012-10-01

Surface modification of tissue engineering scaffolds and substrates is required for improving the efficacy of stem cell therapy by generating physicochemical stimulation promoting proliferation and differentiation of stem cells. However, typical surface modification methods including chemical conjugation or physical absorption have several limitations such as multistep, complicated procedures, surface denaturation, batch-to-batch inconsistencies, and low surface conjugation efficiency. In this study, we report a mussel-inspired, biomimetic approach to surface modification for efficient and reliable manipulation of human neural stem cell (NSC) differentiation and proliferation. Our study demonstrates that polydopamine coating facilitates highly efficient, simple immobilization of neurotrophic growth factors and adhesion peptides onto polymer substrates. The growth factor or peptide-immobilized substrates greatly enhance differentiation and proliferation of human NSCs (human fetal brain-derived NSCs and human induced pluripotent stem cell-derived NSCs) at a level comparable or greater than currently available animal-derived coating materials (Matrigel) with safety issues. Therefore, polydopamine-mediated surface modification can provide a versatile platform technology for developing chemically defined, safe, functional substrates and scaffolds for therapeutic applications of human NSCs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fast evaluation of solid harmonic Gaussian integrals for local resolution-of-the-identity methods and range-separated hybrid functionals.

PubMed

Golze, Dorothea; Benedikter, Niels; Iannuzzi, Marcella; Wilhelm, Jan; Hutter, Jürg

2017-01-21

An integral scheme for the efficient evaluation of two-center integrals over contracted solid harmonic Gaussian functions is presented. Integral expressions are derived for local operators that depend on the position vector of one of the two Gaussian centers. These expressions are then used to derive the formula for three-index overlap integrals where two of the three Gaussians are located at the same center. The efficient evaluation of the latter is essential for local resolution-of-the-identity techniques that employ an overlap metric. We compare the performance of our integral scheme to the widely used Cartesian Gaussian-based method of Obara and Saika (OS). Non-local interaction potentials such as standard Coulomb, modified Coulomb, and Gaussian-type operators, which occur in range-separated hybrid functionals, are also included in the performance tests. The speed-up with respect to the OS scheme is up to three orders of magnitude for both integrals and their derivatives. In particular, our method is increasingly efficient for large angular momenta and highly contracted basis sets.

Fast evaluation of solid harmonic Gaussian integrals for local resolution-of-the-identity methods and range-separated hybrid functionals

NASA Astrophysics Data System (ADS)

Golze, Dorothea; Benedikter, Niels; Iannuzzi, Marcella; Wilhelm, Jan; Hutter, Jürg

2017-01-01

An integral scheme for the efficient evaluation of two-center integrals over contracted solid harmonic Gaussian functions is presented. Integral expressions are derived for local operators that depend on the position vector of one of the two Gaussian centers. These expressions are then used to derive the formula for three-index overlap integrals where two of the three Gaussians are located at the same center. The efficient evaluation of the latter is essential for local resolution-of-the-identity techniques that employ an overlap metric. We compare the performance of our integral scheme to the widely used Cartesian Gaussian-based method of Obara and Saika (OS). Non-local interaction potentials such as standard Coulomb, modified Coulomb, and Gaussian-type operators, which occur in range-separated hybrid functionals, are also included in the performance tests. The speed-up with respect to the OS scheme is up to three orders of magnitude for both integrals and their derivatives. In particular, our method is increasingly efficient for large angular momenta and highly contracted basis sets.

In vitro gene expression by cationized derivatives of an artificial protein with repeated RGD sequences, Pronectin.

PubMed

Hosseinkhani, Hossein; Tabata, Yasuhiko

2003-01-09

The objective of this study is to investigate the efficiency of a non-viral gene carrier with RGD sequences, Pronectin F(+) for gene transfection. The Pronectin F(+) was cationized by introducing ethylenediamine (Ed), spermidine (Sd), and spermine (Sm) to the hydroxyl groups while the corresponding gelatin derivative was prepared similarly because gelatin also has one RGD sequence per molecule. The zeta potential and molecular size of Pronectin F(+) and gelatin derivatives were examined before and after polyion complexation with a plasmid DNA of luciferase. When complexed with the plasmid DNA at the Pronectin F(+)/plasmid DNA mixing ratio of 50, the complex exhibited a zeta potential of about 10 mV, which is similar to that of the gelatin derivative-plasmid DNA complex. Irrespective of the type of Pronectin F(+) and gelatin derivatives, their complexation enabled the apparent molecular size of plasmid DNA to reduce to about 200 nm, the size decreasing with the increased derivative/plasmid DNA weight mixing ratio. The rat gastric mucosal (RGM)-1 cells treated with both complexes exhibited significantly stronger luciferase activities than free plasmid DNA although the enhanced extent was significant for the Sm derivative compared with the corresponding Ed and Sd derivatives. Cell attachment was enhanced by the Pronectin F(+) derivative to a significant high extent compared with the gelatin derivative. The amount of plasmid DNA internalized into the cells was enhanced by the complexation with every Pronectin F(+) derivative compared with the gelatin derivative. For both of Pronectin F(+) and gelatin carriers, the buffering capacity of Sm derivatives was higher than that of Ed and Sd derivatives and comparable to that of polyethyleneimine. It is likely that the high efficiency of gene transfection for the Sm derivative is due to the superior buffering effect. We conclude that the Sm derivative of Pronectin F(+) is promising as a non-viral vector of gene transfection.

Study of chemical reactivity in relation to experimental parameters of efficiency in coumarin derivatives for dye sensitized solar cells using DFT.

PubMed

Soto-Rojo, Rody; Baldenebro-López, Jesús; Glossman-Mitnik, Daniel

2015-06-07

A group of dyes derived from coumarin was studied, which consisted of nine molecules using a very similar manufacturing process of dye sensitized solar cells (DSSCs). Optimized geometries, energy levels of the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and ultraviolet-visible spectra were obtained using theoretical calculations, and they were also compared with experimental conversion efficiencies of the DSSC. The representation of an excited state in terms of natural transition orbitals (NTOs) was studied. Chemical reactivity parameters were calculated and correlated with the experimental data linked to the efficiency of the DSSC. A new proposal was obtained to design new molecular systems and to predict their potential use as a dye in DSSCs.

An Expansion Formula with Higher-Order Derivatives for Fractional Operators of Variable Order

PubMed Central

Almeida, Ricardo

2013-01-01

We obtain approximation formulas for fractional integrals and derivatives of Riemann-Liouville and Marchaud types with a variable fractional order. The approximations involve integer-order derivatives only. An estimation for the error is given. The efficiency of the approximation method is illustrated with examples. As applications, we show how the obtained results are useful to solve differential equations, and problems of the calculus of variations that depend on fractional derivatives of Marchaud type. PMID:24319382

Development of an Automatic Differentiation Version of the FPX Rotor Code

NASA Technical Reports Server (NTRS)

Hu, Hong

1996-01-01

The ADIFOR2.0 automatic differentiator is applied to the FPX rotor code along with the grid generator GRGN3. The FPX is an eXtended Full-Potential CFD code for rotor calculations. The automatic differentiation version of the code is obtained, which provides both non-geometry and geometry sensitivity derivatives. The sensitivity derivatives via automatic differentiation are presented and compared with divided difference generated derivatives. The study shows that automatic differentiation method gives accurate derivative values in an efficient manner.

Synthesis of 5'-deoxy-5'-nucleosideacetic acid derivatives

NASA Technical Reports Server (NTRS)

Harada, Kazuo; Orgel, Leslie E.

1990-01-01

Several new 5'-deoxy-5'-nucleosideacetic acid derivatives have been synthesized by the reactions of alkoxycarbonylmethylene triphenylphosphoranes with nucleoside 5'-aldehydes. The oligomerization of adenine derivatives IIa, IIIa, IV, V and guanine derivatives IIc and IIIc in aqueous solution was studied using a water-soluble carbodiimide as a condensing agent. It is found that the saturated acid (IV) tends to cyclize to the lactone, while IIa and unsaturated acids (IIIa and V) oligomerized efficiently, especially in the presence of poly (U) as a template.

10 CFR 431.17 - Determination of efficiency.

Code of Federal Regulations, 2010 CFR

2010-01-01

... method or methods used; the mathematical model, the engineering or statistical analysis, computer... accordance with § 431.16 of this subpart, or by application of an alternative efficiency determination method... must be: (i) Derived from a mathematical model that represents the mechanical and electrical...

Advantages of using a logarithmic scale in pressure-volume diagrams for Carnot and other heat engine cycles

NASA Astrophysics Data System (ADS)

Shieh, Lih-Yir; Kan, Hung-Chih

2014-04-01

We demonstrate that plotting the P-V diagram of an ideal gas Carnot cycle on a logarithmic scale results in a more intuitive approach for deriving the final form of the efficiency equation. The same approach also facilitates the derivation of the efficiency of other thermodynamic engines that employ adiabatic ideal gas processes, such as the Brayton cycle, the Otto cycle, and the Diesel engine. We finally demonstrate that logarithmic plots of isothermal and adiabatic processes help with visualization in approximating an arbitrary process in terms of an infinite number of Carnot cycles.

Stereospecific Palladium-Catalyzed C-H Arylation of Pyroglutamic Acid Derivatives at the C3 Position Enabled by 8-Aminoquinoline as a Directing Group.

PubMed

Verho, Oscar; Maetani, Micah; Melillo, Bruno; Zoller, Jochen; Schreiber, Stuart L

2017-09-01

An efficient and stereospecific Pd-catalyzed protocol for the C-H arylation of pyroglutamic acid derivatives that uses 8-aminoquinoline as a directing group is described. The reaction was shown to proceed efficiently with a variety of aryl and heteroaryl iodides bearing different functional groups, giving C3-arylated cis products in good to high yields. Removal of the 8-aminoquinoline unit from these C-H arylation products enables access to synthetically useful cis and trans pyroglutamic acid-based building blocks.

The Application of Vinylogous Iminium Salt Derivatives and Microwave Accelerated Vilsmeier-Haack Reactions to Efficient Relay Syntheses of the Polycitone and Storniamide Natural Products

PubMed Central

Gupton, John T.; Banner, Edith J.; Sartin, Melissa D.; Coppock, Matthew B.; Hempel, Jonathan E.; Kharlamova, Anastasia; Fisher, Daniel C.; Giglio, Ben C.; Smith, Kristin L.; Keough, Matt J.; Smith, Timothy M.; Kanters, Rene P.F.; Dominey, Raymond N.; Sikorski, James A.

2008-01-01

Studies directed at the synthesis of polycitone and storniamide natural products via vinylogous iminium salts and microwave accelerated Vilsmeier-Haack formylations are described. The successful strategy relies on the formation of a 2,4-disubstituted pyrrole or a 2,3,4-trisubstituted pyrrole from a vinamidinium salt or vinamidinium salt derivative followed by formylation at the 5-position of the pyrrole. Subsequent transformations of the selectively formylated pyrroles lead to efficient and regiocontrolled relay syntheses of the respective pyrrole containing natural products. PMID:18709182

Enantioselective Organocatalytic Aminomethylation of Aldehydes: A Role for Ionic Interactions and Efficient Access to β2-Amino Acids

PubMed Central

Chi, Yonggui; Gellman, Samuel H.

2009-01-01

Organocatalytic Mannich addition of aldehydes to a formaldehyde-derived iminium species catalyzed by proline-derived chiral pyrrolidines provides β-amino aldehydes with ≥ 90% ee. Mechanistic analysis of the proline-catalyzed reactions suggests that non-hydrogen-bonded ionic interactions at the Mannich reaction transition state can influence stereochemical outcome. The β-amino aldehydes from our process bear a substituent adjacent to the carbonyl and can be efficiently converted to protected β2-amino acids, which are important building blocks for β-peptide foldamers that display useful biological activities. PMID:16719457

Relations between the efficiency, power and dissipation for linear irreversible heat engine at maximum trade-off figure of merit

NASA Astrophysics Data System (ADS)

Iyyappan, I.; Ponmurugan, M.

2018-03-01

A trade of figure of merit (\\dotΩ ) criterion accounts the best compromise between the useful input energy and the lost input energy of the heat devices. When the heat engine is working at maximum \\dotΩ criterion its efficiency increases significantly from the efficiency at maximum power. We derive the general relations between the power, efficiency at maximum \\dotΩ criterion and minimum dissipation for the linear irreversible heat engine. The efficiency at maximum \\dotΩ criterion has the lower bound \

The NASA Aircraft Energy Efficiency Program

NASA Technical Reports Server (NTRS)

Klineberg, J. M.

1978-01-01

The objective of the NASA Aircraft Energy Efficiency Program is to accelerate the development of advanced technology for more energy-efficient subsonic transport aircraft. This program will have application to current transport derivatives in the early 1980s and to all-new aircraft of the late 1980s and early 1990s. Six major technology projects were defined that could result in fuel savings in commercial aircraft: (1) Engine Component Improvement, (2) Energy Efficient Engine, (3) Advanced Turboprops, (4) Energy Efficiency Transport (aerodynamically speaking), (5) Laminar Flow Control, and (6) Composite Primary Structures.

Agrobacterium rhizogenes-mediated transformation of Superroot-derived Lotus corniculatus plants: a valuable tool for functional genomics.

PubMed

Jian, Bo; Hou, Wensheng; Wu, Cunxiang; Liu, Bin; Liu, Wei; Song, Shikui; Bi, Yurong; Han, Tianfu

2009-06-25

Transgenic approaches provide a powerful tool for gene function investigations in plants. However, some legumes are still recalcitrant to current transformation technologies, limiting the extent to which functional genomic studies can be performed on. Superroot of Lotus corniculatus is a continuous root cloning system allowing direct somatic embryogenesis and mass regeneration of plants. Recently, a technique to obtain transgenic L. corniculatus plants from Superroot-derived leaves through A. tumefaciens-mediated transformation was described. However, transformation efficiency was low and it took about six months from gene transfer to PCR identification. In the present study, we developed an A. rhizogenes-mediated transformation of Superroot-derived L. corniculatus for gene function investigation, combining the efficient A. rhizogenes-mediated transformation and the rapid regeneration system of Superroot. The transformation system using A. rhizogenes K599 harbouring pGFPGUSPlus was improved by validating some parameters which may influence the transformation frequency. Using stem sections with one node as explants, a 2-day pre-culture of explants, infection with K599 at OD(600) = 0.6, and co-cultivation on medium (pH 5.4) at 22 degrees C for 2 days enhanced the transformation frequency significantly. As proof of concept, Superroot-derived L. corniculatus was transformed with a gene from wheat encoding an Na+/H+ antiporter (TaNHX2) using the described system. Transgenic Superroot plants were obtained and had increased salt tolerance, as expected from the expression of TaNHX2. A rapid and efficient tool for gene function investigation in L. corniculatus was developed, combining the simplicity and high efficiency of the Superroot regeneration system and the availability of A. rhizogenes-mediated transformation. This system was improved by validating some parameters influencing the transformation frequency, which could reach 92% based on GUS detection. The combination of the highly efficient transformation and the regeneration system of Superroot provides a valuable tool for functional genomics studies in L. corniculatus.

P-selectin- and heparanase-dependent antimetastatic activity of non-anticoagulant heparins.

PubMed

Hostettler, Nina; Naggi, Annamaria; Torri, Giangiacomo; Ishai-Michaeli, Riva; Casu, Benito; Vlodavsky, Israel; Borsig, Lubor

2007-11-01

Vascular cell adhesion molecules, P- and L-selectins, facilitate metastasis of cancer cells in mice by mediating interactions with platelets, endothelium, and leukocytes. Heparanase is an endoglycosidase that degrades heparan sulfate of extracellular matrix, thereby promoting tumor invasion and metastasis. Heparin is known to efficiently attenuate metastasis in different tumor models. Here we identified modified, nonanticoagulant species of heparin that specifically inhibit selectin-mediated cell-cell interactions, heparanase enzymatic activity, or both. We show that selective inhibition of selectin interactions or heparanase with specific heparin derivatives in mouse models of MC-38 colon carcinoma and B16-BL6 melanoma attenuates metastasis. Selectin-specific heparin derivatives attenuated metastasis of MC-38 carcinoma, but heparanase-specific derivatives had no effect, in accordance with the virtual absence of heparanase activity in these cells. Heparin derivatives had no further effect on metastasis in mice deficient in P- and L-selectin, indicating that selectins are the primary targets of heparin antimetastatic activity. Selectin-specific and heparanase-specific derivatives attenuated metastasis of B16-BL6 melanomas to a similar extent. When mice were injected with a derivative containing both heparanase and selectin inhibitory activity, no additional attenuation of metastasis could be observed. Thus, selectin-specific heparin derivatives efficiently attenuated metastasis of both tumor cell types whereas inhibition of heparanase led to reduction of metastasis only in tumor cells producing heparanase.

Sol-Gel Derived Hafnia Coatings

NASA Technical Reports Server (NTRS)

Feldman, Jay D.; Stackpoole, Mairead; Blum, Yigal; Sacks, Michael; Ellerby, Don; Johnson, Sylvia M.; Venkatapathy, Ethiras (Technical Monitor)

2002-01-01

Sol-gel derived hafnia coatings are being developed to provide an oxidation protection layer on ultra-high temperature ceramics for potential use in turbine engines (ultra-efficient engine technology being developed by NASA). Coatings using hafnia sol hafnia filler particles will be discussed along with sol synthesis and characterization.

Characterizing Mechanical and Flow Properties using Injection Falloff Tests, March 28, 2011

EPA Pesticide Factsheets

This presentation asserts that Injection Fall-off Testing is an efficient way to derive in-situ information on most rock types, after-closure analysis can derive rock transmissibility and pore fluid pressure, and this is used to assist in the HF process.

Synthesis and properties of 1,3-dioxo-1H-inden-2(3H)-ylidene fragment and (3-(dicyanomethylene)-5,5-dimethylcyclohex-1-enyl)vinyl fragment containing derivatives of azobenzene for holographic recording materials

NASA Astrophysics Data System (ADS)

Zarins, Elmars; Kokars, Valdis; Ozols, Andris; Augustovs, Peteris

2011-06-01

New glassy 1,3-dioxo-1H-inden-2(3H)-ylidene fragment und (3-(dicyanomethylene)-5,5-dimethylcyclohex-1-enyl)vinyl fragment containing push-pull type derivatives of azobenzene able to create thin layers have been synthesized. Thin films of synthesized glasses for holographic recording were prepared using spin coating technique from saturated chloroform solution. Holographic grating recording in films of 6a-b, 7 and 12 has been experimentally studied at 633 and 532 nm in both transmission and reflection modes with p-p recording beam polarizations. The film 12 was found to be the most efficient at both wavelengths in transmission mode exhibiting the maximum self-diffraction efficiency of 9.9% at 633 nm, and 15.3% at 532 nm. The film of 6a was the most efficient in reflection mode with the maximum selfdiffraction efficiency of about 3%.

Derivation of the King's College London human embryonic stem cell lines.

PubMed

Stephenson, Emma L; Braude, Peter R

2010-04-01

Since the derivation of the first human embryonic stem cell (hESC) line in 1998, there has been substantial interest in the potential of these cells for regenerative medicine and cell therapy and in the use of hESCs carrying clinically relevant genetic mutations as models for disease research and therapeutic target identification. There is still a need to improve derivation efficiency and further the understanding of the basic biology of these cells and to develop clinical grade culture systems with the aim of producing cell lines suitable for subsequent manipulation for therapy. The derivation of initial hESC lines at King's College London is discussed here, with focus on derivation methodology. Each of the derivations was distinctive. Although the stage and morphology of each blastocyst were generally similar in each attempt, the behaviour of the colonies was unpredictable; colony morphology and development was different with each attempt. Days 5, 6 and 7 blastocysts were used successfully, and the number of days until appearance of stem-like cells varied from 4 to 14 d. Routine characterisation analyses were performed on three lines, all of which displayed appropriate marker expression and survived cryopreservation-thaw cycles. From the lines discussed, four are at various stages of the deposition process with the UKSCB, one is pending submission and two are unsuitable for banking. Continued open and transparent reporting of results and collaborations will maximise the efficiency of derivation and facilitate the development of standardised protocols for the derivation and early culture of hESC lines.

Efficient automatic OCR word validation using word partial format derivation and language model

NASA Astrophysics Data System (ADS)

Chen, Siyuan; Misra, Dharitri; Thoma, George R.

2010-01-01

In this paper we present an OCR validation module, implemented for the System for Preservation of Electronic Resources (SPER) developed at the U.S. National Library of Medicine.1 The module detects and corrects suspicious words in the OCR output of scanned textual documents through a procedure of deriving partial formats for each suspicious word, retrieving candidate words by partial-match search from lexicons, and comparing the joint probabilities of N-gram and OCR edit transformation corresponding to the candidates. The partial format derivation, based on OCR error analysis, efficiently and accurately generates candidate words from lexicons represented by ternary search trees. In our test case comprising a historic medico-legal document collection, this OCR validation module yielded the correct words with 87% accuracy and reduced the overall OCR word errors by around 60%.

High-efficiency high performance liquid chromatographic analysis of red wine anthocyanins.

PubMed

de Villiers, André; Cabooter, Deirdre; Lynen, Frédéric; Desmet, Gert; Sandra, Pat

2011-07-22

The analysis of anthocyanins in natural products is of significant relevance in recent times due to the recognised health benefits associated with their consumption. In red grapes and wines in particular, anthocyanins are known to contribute important properties to the sensory (colour and taste), anti-oxidant- and ageing characteristics. However, the detailed investigation of the alteration of these compounds during wine ageing is hampered by the challenges associated with the separation of grape-derived anthocyanins and their derived products. High performance liquid chromatography (HPLC) is primarily used for this purpose, often in combination with mass spectrometric (MS) detection, although conventional HPLC methods provide incomplete resolution. We have previously demonstrated how on-column inter-conversion reactions are responsible for poor chromatographic efficiency in the HPLC analysis of anthocyanins, and how an increase in temperature and decrease in particle size may improve the chromatographic performance. In the current contribution an experimental configuration for the high efficiency analysis of anthocyanins is derived using the kinetic plot method (KPM). Further, it is shown how analysis under optimal conditions, in combination with MS detection, delivers much improved separation and identification of red wine anthocyanins and their derived products. This improved analytical performance holds promise for the in-depth investigation of these influential compounds in wine during ageing. Copyright © 2011 Elsevier B.V. All rights reserved.

Lipid Encapsulation Provides Insufficient Total-Tract Digestibility to Achieve an Optimal Transfer Efficiency of Fatty Acids to Milk Fat

PubMed Central

Bainbridge, Melissa; Kraft, Jana

2016-01-01

Transfer efficiencies of rumen-protected n-3 fatty acids (FA) to milk are low, thus we hypothesized that rumen-protection technologies allow for biohydrogenation and excretion of n-3 FA. The objectives of this study were to i) investigate the ruminal protection and post-ruminal release of the FA derived from the lipid-encapsulated echium oil (EEO), and ii) assess the bioavailability and metabolism of the EEO-derived FA through measuring the FA content in plasma lipid fractions, feces, and milk. The EEO was tested for rumen stability using the in situ nylon bag technique, then the apparent total-tract digestibility was assessed in vivo using six Holstein dairy cattle. Diets consisted of a control (no EEO); 1.5% of dry matter (DM) as EEO and 1.5% DM as encapsulation matrix; and 3% DM as EEO. The EEO was rumen-stable and had no effect on animal production. EEO-derived FA were incorporated into all plasma lipid fractions, with the highest proportion of n-3 FA observed in cholesterol esters. Fecal excretion of EEO-derived FA ranged from 7–14%. Biohydrogenation products increased in milk, plasma, and feces with EEO supplementation. In conclusion, lipid-encapsulation provides inadequate digestibility to achieve an optimal transfer efficiency of n-3 FA to milk. PMID:27741299

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

Greene, Samuel M., E-mail: samuel.greene@chem.ox.ac.uk; Shan, Xiao, E-mail: xiao.shan@chem.ox.ac.uk; Clary, David C., E-mail: david.clary@chem.ox.ac.u

Semiclassical Transition State Theory (SCTST), a method for calculating rate constants of chemical reactions, offers gains in computational efficiency relative to more accurate quantum scattering methods. In full-dimensional (FD) SCTST, reaction probabilities are calculated from third and fourth potential derivatives along all vibrational degrees of freedom. However, the computational cost of FD SCTST scales unfavorably with system size, which prohibits its application to larger systems. In this study, the accuracy and efficiency of 1-D SCTST, in which only third and fourth derivatives along the reaction mode are used, are investigated in comparison to those of FD SCTST. Potential derivatives aremore » obtained from numerical ab initio Hessian matrix calculations at the MP2/cc-pVTZ level of theory, and Richardson extrapolation is applied to improve the accuracy of these derivatives. Reaction barriers are calculated at the CCSD(T)/cc-pVTZ level. Results from FD SCTST agree with results from previous theoretical and experimental studies when Richardson extrapolation is applied. Results from our implementation of 1-D SCTST, which uses only 4 single-point MP2/cc-pVTZ energy calculations in addition to those for conventional TST, agree with FD results to within a factor of 5 at 250 K. This degree of agreement and the efficiency of the 1-D method suggest its potential as a means of approximating rate constants for systems too large for existing quantum scattering methods.« less

Electroreduction of carbon monoxide to liquid fuel on oxide-derived nanocrystalline copper.

PubMed

Li, Christina W; Ciston, Jim; Kanan, Matthew W

2014-04-24

The electrochemical conversion of CO2 and H2O into liquid fuel is ideal for high-density renewable energy storage and could provide an incentive for CO2 capture. However, efficient electrocatalysts for reducing CO2 and its derivatives into a desirable fuel are not available at present. Although many catalysts can reduce CO2 to carbon monoxide (CO), liquid fuel synthesis requires that CO is reduced further, using H2O as a H(+) source. Copper (Cu) is the only known material with an appreciable CO electroreduction activity, but in bulk form its efficiency and selectivity for liquid fuel are far too low for practical use. In particular, H2O reduction to H2 outcompetes CO reduction on Cu electrodes unless extreme overpotentials are applied, at which point gaseous hydrocarbons are the major CO reduction products. Here we show that nanocrystalline Cu prepared from Cu2O ('oxide-derived Cu') produces multi-carbon oxygenates (ethanol, acetate and n-propanol) with up to 57% Faraday efficiency at modest potentials (-0.25 volts to -0.5 volts versus the reversible hydrogen electrode) in CO-saturated alkaline H2O. By comparison, when prepared by traditional vapour condensation, Cu nanoparticles with an average crystallite size similar to that of oxide-derived copper produce nearly exclusive H2 (96% Faraday efficiency) under identical conditions. Our results demonstrate the ability to change the intrinsic catalytic properties of Cu for this notoriously difficult reaction by growing interconnected nanocrystallites from the constrained environment of an oxide lattice. The selectivity for oxygenates, with ethanol as the major product, demonstrates the feasibility of a two-step conversion of CO2 to liquid fuel that could be powered by renewable electricity.

Efficiency and kinetics of the in vitro fertilization process in bovine oocytes with different meiotic competence.

PubMed

Horakova, J; Hanzalova, K; Reckova, Z; Hulinska, P; Machatkova, M

2007-08-01

The aim of the study was to investigate the efficiency and kinetics of fertilization in oocytes with different meiotic competence, as defined by the phase of the follicular wave and follicle size. Oocytes were recovered from cows with synchronized estrus cycles, slaughtered in either the growth (day 3) or the dominant (day 7) phase, separately from large, medium and small follicles. The oocytes were matured and fertilized by a standard protocol. Twenty-four hours after fertilization, the oocytes were denuded from cumulus cells, fixed and stained with bisbensimid Hoechst-PBS. Fertilization was more efficient and the first cleavage was accelerated in growth phase-derived oocytes, as shown by significantly higher (p < or = 0.01) proportions of both normally fertilized and cleaved oocytes (68.8 and 25.1%), in comparison with dominant phase-derived oocytes (44.2 and 10.3%). In the growth-phase derived oocytes, proportions of normally fertilized and cleaved oocytes were significantly higher (p < or = 0.01) in oocytes from large (100.0 and 36.4%) and medium (83.3 and 36.5%) follicles than in those from small (54.8 and 14.6%) follicles. The dominant phase-derived oocytes showed higher proportions of normally fertilized and cleaved oocytes in the populations recovered from small (51.5 and 10.0%) and medium (43.1 and 12.0%) follicles than in those from large (25.0 and 0%) follicles; however, the differences were not significant. It can be concluded that: (i) efficiency and kinetics of fertilization differ in relation to oocyte's meiotic competence; (ii) improved development of embryos from oocytes with greater meiotic competence is associated with a more effective fertilization process.

A site-specific genetic modification for induction of pluripotency and subsequent isolation of derived lung alveolar epithelial type II cells.

PubMed

Yan, Qing; Quan, Yuan; Sun, Huanhuan; Peng, Xinmiao; Zou, Zhengyun; Alcorn, Joseph L; Wetsel, Rick A; Wang, Dachun

2014-02-01

Human induced pluripotent stem cells (hiPSCs) have great therapeutic potential in repairing defective lung alveoli. However, genetic abnormalities caused by vector integrations and low efficiency in generating hiPSCs, as well as difficulty in obtaining transplantable hiPSC-derived cell types are still major obstacles. Here we report a novel strategy using a single nonviral site-specific targeting vector with a combination of Tet-On inducible gene expression system, Cre/lox P switching gene expression system, and alveolar epithelial type II cell (ATIIC)-specific Neomycin(R) transgene expression system. With this strategy, a single copy of all of the required transgenes can be specifically knocked into a site immediately downstream of β-2-microglobulin (B2M) gene locus at a high frequency, without causing B2M dysfunction. Thus, the expression of reprogramming factors, Oct4, Sox2, cMyc, and Klf4, can be precisely regulated for efficient reprogramming of somatic cells into random integration-free or genetic mutation-free hiPSCs. The exogenous reprogramming factor transgenes can be subsequently removed after reprogramming by transient expression of Cre recombinase, and the resulting random integration-free and exogenous reprogramming factor-free hiPSCs can be selectively differentiated into a homogenous population of ATIICs. In addition, we show that these hiPSC-derived ATIICs exhibit ultrastructural characteristics and biological functions of normal ATIICs. When transplanted into bleomycin-challenged mice lungs, hiPSC-derived ATIICs efficiently remain and re-epithelialize injured alveoli to restore pulmonary function, preventing lung fibrosis and increasing survival without tumorigenic side effect. This strategy allows for the first time efficient generation of patient-specific ATIICs for possible future clinical applications. © 2013 AlphaMed Press.

A site-specific genetic modification for induction of pluripotency and subsequent isolation of derived lung alveolar epithelial type II cells

PubMed Central

Yan, Qing; Quan, Yuan; Sun, Huanhuan; Peng, Xinmiao; Zou, Zhengyun; Alcorn, Joseph L.; Wetsel, Rick A.; Wang, Dachun

2013-01-01

Human induced pluripotent stem cells (hiPSCs) have great therapeutic potential in repairing defective lung alveoli. However, genetic abnormalities caused by vector-integrations and low efficiency in generating hiPSCs, as well as difficulty in obtaining transplantable hiPSC-derived cell types, are still major obstacles. Here we report a novel strategy using a single non-viral site-specific-targeting vector with a combination of Tet-On inducible gene expression system, Cre/lox P switching gene expression system, and alveolar epithelial type II cell (ATIIC)-specific NeomycinR trangene expression system. With this strategy, a single copy of all of the required transgenes can be specifically knocked into a site immediately downstream of beta-2-microglobulin (B2M) gene locus at a high frequency, without causing B2M dysfunction. Thus, the expression of reprogramming factors, Oct4, Sox2, cMyc and Klf4, can be precisely regulated for efficient reprogramming of somatic cells into random-integration-free or genetic mutation-free hiPSCs. The exogenous reprogramming factor transgenes can be subsequently removed after reprogramming by transient expression of Cre recombinase, and the resulting random-integration-free and exogenous reprogramming-factor-free hiPSCs can be selectively differentiated into a homogenous population of ATIICs. In addition, we show that these hiPSC-derived ATIICs exhibit ultra-structural characteristics and biological functions of normal ATIICs. When transplanted into bleomycin-challenged mice lungs, hiPSC-derived ATIICs efficiently remain and re-epithelialize injured alveoli to restore pulmonary function, preventing lung fibrosis and increasing survival without tumorigenic side effect. This strategy allows for the first time efficient generation of patient-specific ATIICs for possible future clinical applications. PMID:24123810

Efficient activation of human T cells of both CD4 and CD8 subsets by urease-deficient recombinant Mycobacterium bovis BCG that produced a heat shock protein 70-M. tuberculosis-derived major membrane protein II fusion protein.

PubMed

Mukai, Tetsu; Tsukamoto, Yumiko; Maeda, Yumi; Tamura, Toshiki; Makino, Masahiko

2014-01-01

For the purpose of obtaining Mycobacterium bovis bacillus Calmette-Guérin (BCG) capable of activating human naive T cells, urease-deficient BCG expressing a fusion protein composed of Mycobacterium tuberculosis-derived major membrane protein II (MMP-II) and heat shock protein 70 (HSP70) of BCG (BCG-DHTM) was produced. BCG-DHTM secreted the HSP70-MMP-II fusion protein and effectively activated human monocyte-derived dendritic cells (DCs) by inducing phenotypic changes and enhanced cytokine production. BCG-DHTM-infected DCs activated naive T cells of both CD4 and naive CD8 subsets, in an antigen (Ag)-dependent manner. The T cell activation induced by BCG-DHTM was inhibited by the pretreatment of DCs with chloroquine. The naive CD8(+) T cell activation was mediated by the transporter associated with antigen presentation (TAP) and the proteosome-dependent cytosolic cross-priming pathway. Memory CD8(+) T cells and perforin-producing effector CD8(+) T cells were efficiently produced from the naive T cell population by BCG-DHTM stimulation. Single primary infection with BCG-DHTM in C57BL/6 mice efficiently produced T cells responsive to in vitro secondary stimulation with HSP70, MMP-II, and M. tuberculosis-derived cytosolic protein and inhibited the multiplication of subsequently aerosol-challenged M. tuberculosis more efficiently than did vector control BCG. These results indicate that the introduction of MMP-II and HSP70 into urease-deficient BCG may be useful for improving BCG for control of tuberculosis.

Design and efficient synthesis of novel GM2 analogues with respect to the elucidation of the function of GM2 activator.

PubMed

Komori, Tatsuya; Ando, Takayuki; Imamura, Akihiro; Li, Yu-Teh; Ishida, Hideharu; Kiso, Makoto

2008-10-01

To elucidate the mechanism underlying the hydrolysis of the GalNAcbeta1-->4Gal linkage in ganglioside GM2 [GalNAcbeta1-->4(NeuAcalpha2-->3)Galbeta1-->4Glcbeta1-->1' Cer] by beta-hexosaminidase A (Hex A) with GM2 activator protein, we designed and synthesized two kinds of GM2 linkage analogues-6'-NeuAc-GM2 and alpha-GalNAc-GM2. In this paper, the efficient and systematic synthesis of these GM2 analogues was described. The highlight of our synthesis process is that the key intermediates, newly developed sialyllactose derivatives, were efficiently prepared in sufficient quantities; these derivatives directly served as highly reactive glycosyl acceptors and coupled with GalNTroc donors to furnish the assembly of GM2 tetrasaccharides in large quantities.

Physical effects of DCNQI derivatives doping as an N type organic semiconductor in organic photovoltaic cell performance.

PubMed

Lee, Joo Hyung; Oh, Se Young

2014-08-01

In the previous work, we have reported that organic photovoltaic (OPV) cells using DMDCNQI as an n-type second dopant material showed a high power conversion efficiency (PCE). In the present work, we have synthesized a novel DHDCNQI with long alkyl chains to improve the compatibility between the DHDCNQI dopant molecule and host P3HT polymer. We have fabricated OPV cells consisting of ITO/PEDOT:PSS/P3HT:PCBM:DHDCNQI/Al. We have investigated the characteristics of theses OPV cells using DCNQI derivative dopants from the measurements of the incident photon-to-current collection efficiency and photocurrent. The OPV cell using 3 wt% DHDCNQI exhibited a high PCE of 3.29% due to the high charge separation efficiency, good compatibility and low trap site effect.

AGN outflows and feedback twenty years on

NASA Astrophysics Data System (ADS)

Harrison, C. M.; Costa, T.; Tadhunter, C. N.; Flütsch, A.; Kakkad, D.; Perna, M.; Vietri, G.

2018-03-01

It is twenty years since the seminal works by Magorrian and co-authors and by Silk and Rees, which, along with other related work, ignited an explosion of publications connecting active galactic nucleus (AGN)-driven outflows to galaxy evolution. With a surge in observations of AGN outflows, studies are attempting to test AGN feedback models directly using the outflow properties. With a focus on outflows traced by optical and CO emission lines, we discuss significant challenges that greatly complicate this task, from both an observational and theoretical perspective. We highlight the observational uncertainties involved and the assumptions required when deriving kinetic coupling efficiencies (that is, outflow kinetic power as a fraction of AGN luminosity) from typical observations. Based on recent models we demonstrate that extreme caution should be taken when comparing observationally derived kinetic coupling efficiencies to coupling efficiencies from fiducial feedback models.

Langerhans cells utilize CD1a and langerin to efficiently present nonpeptide antigens to T cells

PubMed Central

Hunger, Robert E.; Sieling, Peter A.; Ochoa, Maria Teresa; Sugaya, Makoto; Burdick, Anne E.; Rea, Thomas H.; Brennan, Patrick J.; Belisle, John T.; Blauvelt, Andrew; Porcelli, Steven A.; Modlin, Robert L.

2004-01-01

Langerhans cells (LCs) constitute a subset of DCs that initiate immune responses in skin. Using leprosy as a model, we investigated whether expression of CD1a and langerin, an LC-specific C-type lectin, imparts a specific functional role to LCs. LC-like DCs and freshly isolated epidermal LCs presented nonpeptide antigens of Mycobacterium leprae to T cell clones derived from a leprosy patient in a CD1a-restricted and langerin-dependent manner. LC-like DCs were more efficient at CD1a-restricted antigen presentation than monocyte-derived DCs. LCs in leprosy lesions coexpress CD1a and langerin, placing LCs in position to efficiently present a subset of antigens to T cells as part of the host response to human infectious disease. PMID:14991068

A DFT study of pyrazine derivatives and their Fe complexes in corrosion inhibition process

NASA Astrophysics Data System (ADS)

Behzadi, Hadi; Roonasi, Payman; Momeni, Mohammad Jafar; Manzetti, Sergio; Esrafili, Mehdi D.; Obot, I. B.; Yousefvand, Mostafa; Morteza Mousavi-Khoshdel, S.

2015-04-01

The DFT/B3LYP calculations were applied to investigate the relationship between electronic properties and corrosion inhibition efficiency of three pyrazine derivatives, 2-methylpyrazine (MP), 2-aminopyrazine (AP) and 2-amino-5-bromopyrazine (ABP). To take into account the solution acidity in experimental conditions, all possible mono-protonated forms, that is protonation at N1, N4 and NH2 sites, as well as the non-protonated form were considered. The molecular orbital analysis showed a good correlation between EHOMO, ELUMO and ΔE (EHOMO - ELUMO) with inhibition efficiency of the three pyrazine derivatives. Four types of interactions between iron and pyrazine molecules, i.e. Fe-π, Fe-N1, Fe-N4 and Fe-NH2 were included in the calculations. As a new approach to this system, inhibition mechanism of the three pyrazine molecules has been discussed in detail based on these four types of interactions. It was found that all four interactions are energetically important. The flat pyrazine ring was substantially deformed followed by a Fe-π interaction. The calculated binding energy of ABP in all forms was found to be higher than two other pyrazines, which is consistent with experimentally observed highest corrosion inhibition efficiency. The lack of Fe-NH2 interaction for MP molecule seems to be the reason for its lower corrosion inhibition efficiency.

Efficient Molecular Organic Light-Emitting Diodes Based on Silole Derivatives

DTIC Science & Technology

2003-01-01

TPD) and tris-(8-hydroxyquinoline) aluminum ( Alq3 ), commonly used in MOLEDs, have hole and electron mobilities that differ by a factor of ~1000 (~10...and subsequent device degradation. In addition to the widely used electron transporter Alq3 , [8] derivatives of nathrolines, [7] oxadiazoles, [9

An efficient and more sustainable one-step continuous-flow multicomponent synthesis approach to chromene derivatives

EPA Science Inventory

A simple and rapid one-step continuous-flow synthesis route has been developed for the preparation of chromene derivatives from the reaction of aromatic aldehydes, α-cyanomethylene compounds and naphthols. In this contribution, a one-step continuous-flow protocol in a continuous ...

Sensitivity analysis for large-scale problems

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Whitworth, Sandra L.

1987-01-01

The development of efficient techniques for calculating sensitivity derivatives is studied. The objective is to present a computational procedure for calculating sensitivity derivatives as part of performing structural reanalysis for large-scale problems. The scope is limited to framed type structures. Both linear static analysis and free-vibration eigenvalue problems are considered.

Lignin-Derived Carbon Fibers as Efficient Heterogeneous Solid Acid Catalysts for Esterification of Oleic Acid

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

Adhikari, Shiba P.; Hood, Zachary D.; Gallego, Nidia C.

Here, the production of biodiesel by the esterification of oleic acid, as an example of free fatty acid (FFA), was explored by using a new solid acid catalyst derived from lignin, a highly abundant low-cost biomass material. The catalyst was synthesized from lignin-derived carbon fiber by straightforward sulfonation and contains 1.86 mmol/g of sulfonic acid (-SO 3H) groups. The catalyst was characterized by a variety of techniques including PXRD, TGA, TPD-MS, SEM, and XPS to understand the surface chemistry and the result of sulfonation. It was found that the sulfonated lignin-derived carbon fiber (CF-SO 3H) catalyst was very efficient atmore » esterifying oleic acid at 80 oC in 4 hours, with 10 wt. % catalyst (in terms of oleic acid content) and at a 10:1 molar ratio of methanol: oleic acid with a yield of 92%. Furthermore, the catalyst can be reused with no significant loss in activity after 4 cycles. Hence, synthesizing solid acid catalysts from lignin-derived carbon fiber affords a novel strategy for producing biodiesel via ‘green chemistry’.« less

Lignin-Derived Carbon Fibers as Efficient Heterogeneous Solid Acid Catalysts for Esterification of Oleic Acid

DOE PAGES

Adhikari, Shiba P.; Hood, Zachary D.; Gallego, Nidia C.; ...

2018-06-04

Here, the production of biodiesel by the esterification of oleic acid, as an example of free fatty acid (FFA), was explored by using a new solid acid catalyst derived from lignin, a highly abundant low-cost biomass material. The catalyst was synthesized from lignin-derived carbon fiber by straightforward sulfonation and contains 1.86 mmol/g of sulfonic acid (-SO 3H) groups. The catalyst was characterized by a variety of techniques including PXRD, TGA, TPD-MS, SEM, and XPS to understand the surface chemistry and the result of sulfonation. It was found that the sulfonated lignin-derived carbon fiber (CF-SO 3H) catalyst was very efficient atmore » esterifying oleic acid at 80 oC in 4 hours, with 10 wt. % catalyst (in terms of oleic acid content) and at a 10:1 molar ratio of methanol: oleic acid with a yield of 92%. Furthermore, the catalyst can be reused with no significant loss in activity after 4 cycles. Hence, synthesizing solid acid catalysts from lignin-derived carbon fiber affords a novel strategy for producing biodiesel via ‘green chemistry’.« less

Efficient and Reproducible Myogenic Differentiation from Human iPS Cells: Prospects for Modeling Miyoshi Myopathy In Vitro

PubMed Central

Tanaka, Akihito; Woltjen, Knut; Miyake, Katsuya; Hotta, Akitsu; Ikeya, Makoto; Yamamoto, Takuya; Nishino, Tokiko; Shoji, Emi; Sehara-Fujisawa, Atsuko; Manabe, Yasuko; Fujii, Nobuharu; Hanaoka, Kazunori; Era, Takumi; Yamashita, Satoshi; Isobe, Ken-ichi; Kimura, En; Sakurai, Hidetoshi

2013-01-01

The establishment of human induced pluripotent stem cells (hiPSCs) has enabled the production of in vitro, patient-specific cell models of human disease. In vitro recreation of disease pathology from patient-derived hiPSCs depends on efficient differentiation protocols producing relevant adult cell types. However, myogenic differentiation of hiPSCs has faced obstacles, namely, low efficiency and/or poor reproducibility. Here, we report the rapid, efficient, and reproducible differentiation of hiPSCs into mature myocytes. We demonstrated that inducible expression of myogenic differentiation1 (MYOD1) in immature hiPSCs for at least 5 days drives cells along the myogenic lineage, with efficiencies reaching 70–90%. Myogenic differentiation driven by MYOD1 occurred even in immature, almost completely undifferentiated hiPSCs, without mesodermal transition. Myocytes induced in this manner reach maturity within 2 weeks of differentiation as assessed by marker gene expression and functional properties, including in vitro and in vivo cell fusion and twitching in response to electrical stimulation. Miyoshi Myopathy (MM) is a congenital distal myopathy caused by defective muscle membrane repair due to mutations in DYSFERLIN. Using our induced differentiation technique, we successfully recreated the pathological condition of MM in vitro, demonstrating defective membrane repair in hiPSC-derived myotubes from an MM patient and phenotypic rescue by expression of full-length DYSFERLIN (DYSF). These findings not only facilitate the pathological investigation of MM, but could potentially be applied in modeling of other human muscular diseases by using patient-derived hiPSCs. PMID:23626698

High-Performing Polycarbazole Derivatives for Efficient Solution-Processing of Organic Solar Cells in Air.

PubMed

Burgués-Ceballos, Ignasi; Hermerschmidt, Felix; Akkuratov, Alexander V; Susarova, Diana K; Troshin, Pavel A; Choulis, Stelios A

2015-12-21

The application of conjugated materials in organic photovoltaics (OPVs) is usually demonstrated in lab-scale spin-coated devices that are processed under controlled inert conditions. Although this is a necessary step to prove high efficiency, testing of promising materials in air should be done in the early stages of research to validate their real potential for low-cost, solution-processed, and large-scale OPVs. Also relevant for approaching commercialization needs is the use of printing techniques that are compatible with upscaling. Here, solution processing of organic solar cells based on three new poly(2,7-carbazole) derivatives is efficiently transferred, without significant losses, to air conditions and to several deposition methods using a simple device architecture. High efficiencies in the range between 5.0 % and 6.3 % are obtained in (rigid) spin-coated, doctor-bladed, and (flexible) slot-die-coated devices, which surpass the reference devices based on poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT). In contrast, inkjet printing does not provide reliable results with the presented polymers, which is attributed to their high molecular weight. When the device area in the best-performing system is increased from 9 mm(2) to 0.7 cm(2), the efficiency drops from 6.2 % to 5.0 %. Photocurrent mapping reveals inhomogeneous current generation derived from changes in the thickness of the active layer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inter-relationships among alternative definitions of feed efficiency in grazing lactating dairy cows.

PubMed

Hurley, A M; López-Villalobos, N; McParland, S; Kennedy, E; Lewis, E; O'Donovan, M; Burke, J L; Berry, D P

2016-01-01

International interest in feed efficiency, and in particular energy intake and residual energy intake (REI), is intensifying due to a greater global demand for animal-derived protein and energy sources. Feed efficiency is a trait of economic importance, and yet is overlooked in national dairy cow breeding goals. This is due primarily to a lack of accurate data on commercial animals, but also a lack of clarity on the most appropriate definition of the feed intake and utilization complex. The objective of the present study was to derive alternative definitions of energetic efficiency in grazing lactating dairy cows and to quantify the inter-relationships among these alternative definitions. Net energy intake (NEI) from pasture and concentrate intake was estimated up to 8 times per lactation for 2,693 lactations from 1,412 Holstein-Friesian cows. Energy values of feed were based on the French Net Energy system where 1 UFL is the net energy requirements for lactation equivalent of 1kg of air-dry barley. A total of 8,183 individual feed intake measurements were available. Energy balance was defined as the difference between NEI and energy expenditure. Efficiency traits were either ratio-based or residual-based; the latter were derived from least squares regression models. Residual energy intake was defined as NEI minus predicted energy to fulfill the requirements for the various energy sinks. The energy sinks (e.g., NEL, metabolic live weight) and additional contributors to energy kinetics (e.g., live weight loss) combined, explained 59% of the variation in NEI, implying that REI represented 41% of the variance in total NEI. The most efficient 10% of test-day records, as defined by REI (n=709), on average were associated with a 7.59 UFL/d less NEI (average NEI of the entire population was 16.23 UFL/d) than the least efficient 10% of test-day records based on REI (n=709). Additionally, the most efficient 10% of test-day records, as defined by REI, were associated with superior energy conversion efficiency (ECE, i.e., NEL divided by NEI; ECE=0.55) compared with the least efficient 10% of test-day records (ECE=0.33). Moreover, REI was positively correlated with energy balance, implying that more negative REI animals (i.e., deemed more efficient) are expected to be, on average, in greater negative energy balance. Many of the correlations among the 14 defined efficiency traits differed from unity, implying that each trait is measuring a different aspect of efficiency. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Optimization of Turbine Engine Cycle Analysis with Analytic Derivatives

NASA Technical Reports Server (NTRS)

Hearn, Tristan; Hendricks, Eric; Chin, Jeffrey; Gray, Justin; Moore, Kenneth T.

2016-01-01

A new engine cycle analysis tool, called Pycycle, was recently built using the OpenMDAO framework. This tool uses equilibrium chemistry based thermodynamics, and provides analytic derivatives. This allows for stable and efficient use of gradient-based optimization and sensitivity analysis methods on engine cycle models, without requiring the use of finite difference derivative approximation methods. To demonstrate this, a gradient-based design optimization was performed on a multi-point turbofan engine model. Results demonstrate very favorable performance compared to an optimization of an identical model using finite-difference approximated derivatives.

Precipitation Efficiency in the Tropical Deep Convective Regime

NASA Technical Reports Server (NTRS)

Li, Xiaofan; Sui, C.-H.; Lau, K.-M.; Lau, William K. M. (Technical Monitor)

2001-01-01

Precipitation efficiency in the tropical deep convective regime is analyzed based on a 2-D cloud resolving simulation. The cloud resolving model is forced by the large-scale vertical velocity and zonal wind and large-scale horizontal advections derived from TOGA COARE for a 20-day period. Precipitation efficiency may be defined as a ratio of surface rain rate to sum of surface evaporation and moisture convergence (LSPE) or a ratio of surface rain rate to sum of condensation and deposition rates of supersaturated vapor (CMPE). Moisture budget shows that the atmosphere is moistened (dryed) when the LSPE is less (more) than 100 %. The LSPE could be larger than 100 % for strong convection. This indicates that the drying processes should be included in cumulus parameterization to avoid moisture bias. Statistical analysis shows that the sum of the condensation and deposition rates is bout 80 % of the sum of the surface evaporation rate and moisture convergence, which ads to proportional relation between the two efficiencies when both efficiencies are less han 100 %. The CMPE increases with increasing mass-weighted mean temperature and creasing surface rain rate. This suggests that precipitation is more efficient for warm environment and strong convection. Approximate balance of rates among the condensation, deposition, rain, and the raindrop evaporation is used to derive an analytical solution of the CMPE.

Simple and Practical Efficiency Lessons

ERIC Educational Resources Information Center

Kolpin, Van

2018-01-01

The derivation of conditions necessary for Pareto efficient production and exchange is a lesson frequently showcased in microeconomic theory textbooks. Traditional delivery of this lesson is, however, limited in its scope of application and can be unnecessarily convoluted. The author shows that the universe of application is greatly expanded and a…

Highly efficient one-pot three-component synthesis of naphthopyran derivatives in water catalyzed by hydroxyapatite

EPA Science Inventory

An expeditious and efficient protocol for the synthesis of naphthopyrans has been developed that proceeds via one-pot three-component sequential reaction in water catalyzed by hydroxyapatite or sodium-modified-hydroxyapatite. The title compounds have been obtained in high yield a...

Rational construction of a stable Zn4O-based MOF for highly efficient CO2 capture and conversion.

PubMed

Zhou, Hui-Fang; Liu, Bo; Hou, Lei; Zhang, Wen-Yan; Wang, Yao-Yu

2018-01-11

By employing a carboxylate ligand derived from benzene-1,4-dicarboxylate, a chemically stable Zn 4 O-based self-penetrating metal-organic framework has been rationally synthesized, which exhibits high CO 2 adsorption and efficient catalytic conversion for CO 2 cycloaddition.

10 CFR 431.197 - Manufacturer's determination of efficiency for distribution transformers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... methods used; the mathematical model, the engineering or statistical analysis, computer simulation or... (b)(3) of this section, or by application of an alternative efficiency determination method (AEDM... section only if: (i) The AEDM has been derived from a mathematical model that represents the electrical...

77 FR 56067 - Changes To Implement Derivation Proceedings

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

... regulations is to establish a more efficient and streamlined patent system. The preamble of this notice sets... patent system, the efficient administration of the Office, and the ability of the Office to complete the... substantially same invention, thus promoting the useful arts by participating in the patent system. Facially...

Efficient numerical method for solving Cauchy problem for the Gamma equation

NASA Astrophysics Data System (ADS)

Koleva, Miglena N.

2011-12-01

In this work we consider Cauchy problem for the so called Gamma equation, derived by transforming the fully nonlinear Black-Scholes equation for option price into a quasilinear parabolic equation for the second derivative (Greek) Γ = VSS of the option price V. We develop an efficient numerical method for solving the model problem concerning different volatility terms. Using suitable change of variables the problem is transformed on finite interval, keeping original behavior of the solution at the infinity. Then we construct Picard-Newton algorithm with adaptive mesh step in time, which can be applied also in the case of non-differentiable functions. Results of numerical simulations are given.

The Comparative Photodegradation Activities of Pentachlorophenol (PCP) and Polychlorinated Biphenyls (PCBs) Using UV Alone and TiO2-Derived Photocatalysts in Methanol Soil Washing Solution

PubMed Central

Zhou, Zeyu; Zhang, Yaxin; Wang, Hongtao; Chen, Tan; Lu, Wenjing

2014-01-01

Photochemical treatment is increasingly being applied to remedy environmental problems. TiO2-derived catalysts are efficiently and widely used in photodegradation applications. The efficiency of various photochemical treatments, namely, the use of UV irradiation without catalyst or with TiO2/graphene-TiO2 photodegradation methods was determined by comparing the photodegadation of two main types of hydrophobic chlorinated aromatic pollutants, namely, pentachlorophenol (PCP) and polychlorinated biphenyls (PCBs). Results show that photodegradation in methanol solution under pure UV irradiation was more efficient than that with either one of the catalysts tested, contrary to previous results in which photodegradation rates were enhanced using TiO2-derived catalysts. The effects of various factors, such as UV light illumination, addition of methanol to the solution, catalyst dosage, and the pH of the reaction mixture, were examined. The degradation pathway was deduced. The photochemical treatment in methanol soil washing solution did not benefit from the use of the catalysts tested. Pure UV irradiation was sufficient for the dechlorination and degradation of the PCP and PCBs. PMID:25254664

Efficient minimization of multipole electrostatic potentials in torsion space

PubMed Central

Bodmer, Nicholas K.

2018-01-01

The development of models of macromolecular electrostatics capable of delivering improved fidelity to quantum mechanical calculations is an active field of research in computational chemistry. Most molecular force field development takes place in the context of models with full Cartesian coordinate degrees of freedom. Nevertheless, a number of macromolecular modeling programs use a reduced set of conformational variables limited to rotatable bonds. Efficient algorithms for minimizing the energies of macromolecular systems with torsional degrees of freedom have been developed with the assumption that all atom-atom interaction potentials are isotropic. We describe novel modifications to address the anisotropy of higher order multipole terms while retaining the efficiency of these approaches. In addition, we present a treatment for obtaining derivatives of atom-centered tensors with respect to torsional degrees of freedom. We apply these results to enable minimization of the Amoeba multipole electrostatics potential in a system with torsional degrees of freedom, and validate the correctness of the gradients by comparison to finite difference approximations. In the interest of enabling a complete model of electrostatics with implicit treatment of solvent-mediated effects, we also derive expressions for the derivative of solvent accessible surface area with respect to torsional degrees of freedom. PMID:29641557

Quantum efficiency harmonic analysis of exciton annihilation in organic light emitting diodes

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

Price, J. S.; Giebink, N. C., E-mail: ncg2@psu.edu

2015-06-29

Various exciton annihilation processes are known to impact the efficiency roll-off of organic light emitting diodes (OLEDs); however, isolating and quantifying their contribution in the presence of other factors such as changing charge balance continue to be a challenge for routine device characterization. Here, we analyze OLED electroluminescence resulting from a sinusoidal dither superimposed on the device bias and show that nonlinearity between recombination current and light output arising from annihilation mixes the quantum efficiency measured at different dither harmonics in a manner that depends uniquely on the type and magnitude of the annihilation process. We derive a series ofmore » analytical relations involving the DC and first harmonic external quantum efficiency that enable annihilation rates to be quantified through linear regression independent of changing charge balance and evaluate them for prototypical fluorescent and phosphorescent OLEDs based on the emitters 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran and platinum octaethylporphyrin, respectively. We go on to show that, in most cases, it is sufficient to calculate the needed quantum efficiency harmonics directly from derivatives of the DC light versus current curve, thus enabling this analysis to be conducted solely from standard light-current-voltage measurement data.« less

Versatile Indolocarbazole-Isomer Derivatives as Highly Emissive Emitters and Ideal Hosts for Thermally Activated Delayed Fluorescent OLEDs with Alleviated Efficiency Roll-Off.

PubMed

Zhang, Dongdong; Song, Xiaozeng; Cai, Minghan; Kaji, Hironori; Duan, Lian

2018-02-01

Maintaining high efficiency at high brightness levels is an exigent challenge for real-world applications of thermally activated delayed fluorescent organic light-emitting diodes (TADF-OLEDs). Here, versatile indolocarbazole-isomer derivatives are developed as highly emissive emitters and ideal hosts for TADF-OLEDs to alleviate efficiency roll-off. It is observed that photophysical and electronic properties of these compounds can be well modulated by varying the indolocarbazole isomers. A photoluminescence quantum yield (η PL ) approaching unity and a maximum external quantum efficiency (EQE max ) of 25.1% are obtained for the emitter with indolo[3,2-a]carbazolyl subunit. Remarkably, record-high EQE/power efficiency of 26.2%/69.7 lm W -1 at the brightness level of 5000 cd m -2 with a voltage of only 3.74 V are also obtained using the same isomer as the host in a green TADF-OLED. It is evident that TADF hosts with high η PL values, fast reverse intersystem crossing processes, and balanced charge transport properties may open the path toward roll-off-free TADF-OLEDs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficient temporal and interlayer parameter prediction for weighted prediction in scalable high efficiency video coding

NASA Astrophysics Data System (ADS)

Tsang, Sik-Ho; Chan, Yui-Lam; Siu, Wan-Chi

2017-01-01

Weighted prediction (WP) is an efficient video coding tool that was introduced since the establishment of the H.264/AVC video coding standard, for compensating the temporal illumination change in motion estimation and compensation. WP parameters, including a multiplicative weight and an additive offset for each reference frame, are required to be estimated and transmitted to the decoder by slice header. These parameters cause extra bits in the coded video bitstream. High efficiency video coding (HEVC) provides WP parameter prediction to reduce the overhead. Therefore, WP parameter prediction is crucial to research works or applications, which are related to WP. Prior art has been suggested to further improve the WP parameter prediction by implicit prediction of image characteristics and derivation of parameters. By exploiting both temporal and interlayer redundancies, we propose three WP parameter prediction algorithms, enhanced implicit WP parameter, enhanced direct WP parameter derivation, and interlayer WP parameter, to further improve the coding efficiency of HEVC. Results show that our proposed algorithms can achieve up to 5.83% and 5.23% bitrate reduction compared to the conventional scalable HEVC in the base layer for SNR scalability and 2× spatial scalability, respectively.

Validated biomechanical model for efficiency and speed of rowing.

PubMed

Pelz, Peter F; Vergé, Angela

2014-10-17

The speed of a competitive rowing crew depends on the number of crew members, their body mass, sex and the type of rowing-sweep rowing or sculling. The time-averaged speed is proportional to the rower's body mass to the 1/36th power, to the number of crew members to the 1/9th power and to the physiological efficiency (accounted for by the rower's sex) to the 1/3rd power. The quality of the rowing shell and propulsion system is captured by one dimensionless parameter that takes the mechanical efficiency, the shape and drag coefficient of the shell and the Froude propulsion efficiency into account. We derive the biomechanical equation for the speed of rowing by two independent methods and further validate it by successfully predicting race times. We derive the theoretical upper limit of the Froude propulsion efficiency for low viscous flows. This upper limit is shown to be a function solely of the velocity ratio of blade to boat speed (i.e., it is completely independent of the blade shape), a result that may also be of interest for other repetitive propulsion systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Efficient evaluation of the Coulomb force in the Gaussian and finite-element Coulomb method.

PubMed

Kurashige, Yuki; Nakajima, Takahito; Sato, Takeshi; Hirao, Kimihiko

2010-06-28

We propose an efficient method for evaluating the Coulomb force in the Gaussian and finite-element Coulomb (GFC) method, which is a linear-scaling approach for evaluating the Coulomb matrix and energy in large molecular systems. The efficient evaluation of the analytical gradient in the GFC is not straightforward as well as the evaluation of the energy because the SCF procedure with the Coulomb matrix does not give a variational solution for the Coulomb energy. Thus, an efficient approximate method is alternatively proposed, in which the Coulomb potential is expanded in the Gaussian and finite-element auxiliary functions as done in the GFC. To minimize the error in the gradient not just in the energy, the derived functions of the original auxiliary functions of the GFC are used additionally for the evaluation of the Coulomb gradient. In fact, the use of the derived functions significantly improves the accuracy of this approach. Although these additional auxiliary functions enlarge the size of the discretized Poisson equation and thereby increase the computational cost, it maintains the near linear scaling as the GFC and does not affects the overall efficiency of the GFC approach.

Deriving the exact nonadiabatic quantum propagator in the mapping variable representation.

PubMed

Hele, Timothy J H; Ananth, Nandini

2016-12-22

We derive an exact quantum propagator for nonadiabatic dynamics in multi-state systems using the mapping variable representation, where classical-like Cartesian variables are used to represent both continuous nuclear degrees of freedom and discrete electronic states. The resulting Liouvillian is a Moyal series that, when suitably approximated, can allow for the use of classical dynamics to efficiently model large systems. We demonstrate that different truncations of the exact Liouvillian lead to existing approximate semiclassical and mixed quantum-classical methods and we derive an associated error term for each method. Furthermore, by combining the imaginary-time path-integral representation of the Boltzmann operator with the exact Liouvillian, we obtain an analytic expression for thermal quantum real-time correlation functions. These results provide a rigorous theoretical foundation for the development of accurate and efficient classical-like dynamics to compute observables such as electron transfer reaction rates in complex quantized systems.

Alternative stable qP wave equations in TTI media with their applications for reverse time migration

NASA Astrophysics Data System (ADS)

Zhou, Yang; Wang, Huazhong; Liu, Wenqing

2015-10-01

Numerical instabilities may arise if the spatial variation of symmetry axis is handled improperly when implementing P-wave modeling and reverse time migration in heterogeneous tilted transversely isotropic (TTI) media, especially in the cases where fast changes exist in TTI symmetry axis’ directions. Based on the pseudo-acoustic approximation to anisotropic elastic wave equations in Cartesian coordinates, alternative second order qP (quasi-P) wave equations in TTI media are derived in this paper. Compared with conventional stable qP wave equations, the proposed equations written in stress components contain only spatial derivatives of wavefield variables (stress components) and are free from spatial derivatives involving media parameters. These lead to an easy and efficient implementation for stable P-wave modeling and imaging. Numerical experiments demonstrate the stability and computational efficiency of the presented equations in complex TTI media.

Pyridine-ring containing twisttetraazaacene: Synthesis, physical properties, crystal structure and picric acid sensing.

PubMed

Yu, Xianglin; Wan, Jiaqi; Chen, Shao; Li, Miao; Gao, Junkuo; Yang, Li; Wang, Huisheng; Chen, Dugang; Pan, Zhiquan; Li, Junbo

2017-11-01

Novel pyridine-ring containing twisttetraazaacene 9,14-diphenylpyreno[4,5-g]isoquinoline (1) and its full-carbon derivative 9,14-diphenyldibenzo[de,qr]tetracene (2) have been synthesized and fully characterized. Studies showed that compound 1 could identify picric acid (PA) over other common nitro compounds with high selectivity and sensitivity. Upon the addition of PA, the emission peak of compound 1 in CH 3 CN was red shifted from 447 to 555nm with a fluorescence quenching efficiency as high as 95%, the detection limit was calculated to be 2.42μM, while its full-carbon derivative (2) could not exhibit this kind of performance. The possible mechanism with the enhanced PA detection efficiency in pyridine-ring containing twisttetraazaacene (1) than its full-carbon derivative (2) was also investigated. Copyright © 2017 Elsevier B.V. All rights reserved.

Tailoring noise frequency spectrum between two consecutive second derivative filtering procedures to improve liquid chromatography-mass spectrometry determinations.

PubMed

Wang, Shau-Chun; Lin, Chiao-Juan; Chiang, Shu-Min; Yu, Sung-Nien

2008-03-15

This paper reports a simple chemometric technique to alter the noise spectrum of a liquid chromatography-mass spectrometry (LC-MS) chromatogram between two consecutive second-derivative filter procedures to improve the peak signal-to-noise (S/N) ratio enhancement. This technique is to multiply one second-derivative filtered LC-MS chromatogram with another artificial chromatogram added with thermal noises prior to the other second-derivative filter. Because the second-derivative filter cannot eliminate frequency components within its own filter bandwidth, more efficient peak S/N ratio improvement cannot be accomplished using consecutive second-derivative filter procedures to process LC-MS chromatograms. In contrast, when the second-derivative filtered LC-MS chromatogram is conditioned with the multiplication alteration prior to the other second-derivative filter, much better ratio improvement is achieved. The noise frequency spectrum of the second-derivative filtered chromatogram, which originally contains frequency components within the filter bandwidth, is altered to span a broader range with multiplication operation. When the frequency range of this modified noise spectrum shifts toward the other regimes, the other second-derivative filter, working as a band-pass filter, is able to provide better filtering efficiency to obtain higher peak S/N ratios. Real LC-MS chromatograms, of which 5-fold peak S/N ratio improvement achieved with two consecutive second-derivative filters remains the same S/N ratio improvement using a one-step second-derivative filter, are improved to accomplish much better ratio enhancement, approximately 25-fold or higher when the noise frequency spectrum is modified between two matched filters. The linear standard curve using the filtered LC-MS signals is validated. The filtered LC-MS signals are also more reproducible. The more accurate determinations of very low-concentration samples (S/N ratio about 5-7) are obtained via standard addition procedures using the filtered signals rather than the determinations using the original signals.

Synthesis and antibacterial activity of novel enolphosphate derivatives.

PubMed

Grison, Claude; Barthes, Nicolas; Finance, Chantal; Duval, Raphael E

2010-10-01

A new class of enolphosphates derivatives, the 1-alkenyldiphosphates, was designed and a rapid and efficient synthesis for these compounds was developed. These new molecules showed interesting in vitro antibacterial activities (MIC) against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative pathogens including Pseudomonas aeruginosa and Escherichia coli. 2010 Elsevier Inc. All rights reserved.

A new practical approach towards the synthesis of unsymmetric and symmetric 1,10-phenanthroline derivatives at room temperature.

PubMed

Cheng, Yongfeng; Han, Xuesong; Ouyang, Huangche; Rao, Yu

2012-03-18

An efficient method towards synthesis of 1,10-phenanthrolines is described. Through Lewis acid-catalyzed annulation reaction between 3-ethoxycyclobutanones and 8-aminoquinolines, a variety of unsymmetric and symmetric 1,10-phenanthroline derivatives were readily prepared with high regioselectivity at room temperature.

Method for hyperspectral imagery exploitation and pixel spectral unmixing

NASA Technical Reports Server (NTRS)

Lin, Ching-Fang (Inventor)

2003-01-01

An efficiently hybrid approach to exploit hyperspectral imagery and unmix spectral pixels. This hybrid approach uses a genetic algorithm to solve the abundance vector for the first pixel of a hyperspectral image cube. This abundance vector is used as initial state in a robust filter to derive the abundance estimate for the next pixel. By using Kalman filter, the abundance estimate for a pixel can be obtained in one iteration procedure which is much fast than genetic algorithm. The output of the robust filter is fed to genetic algorithm again to derive accurate abundance estimate for the current pixel. The using of robust filter solution as starting point of the genetic algorithm speeds up the evolution of the genetic algorithm. After obtaining the accurate abundance estimate, the procedure goes to next pixel, and uses the output of genetic algorithm as the previous state estimate to derive abundance estimate for this pixel using robust filter. And again use the genetic algorithm to derive accurate abundance estimate efficiently based on the robust filter solution. This iteration continues until pixels in a hyperspectral image cube end.

High Color-Purity Green, Orange, and Red Light-Emitting Didoes Based on Chemically Functionalized Graphene Quantum Dots

NASA Astrophysics Data System (ADS)

Kwon, Woosung; Kim, Young-Hoon; Kim, Ji-Hee; Lee, Taehyung; Do, Sungan; Park, Yoonsang; Jeong, Mun Seok; Lee, Tae-Woo; Rhee, Shi-Woo

2016-04-01

Chemically derived graphene quantum dots (GQDs) to date have showed very broad emission linewidth due to many kinds of chemical bondings with different energy levels, which significantly degrades the color purity and color tunability. Here, we show that use of aniline derivatives to chemically functionalize GQDs generates new extrinsic energy levels that lead to photoluminescence of very narrow linewidths. We use transient absorption and time-resolved photoluminescence spectroscopies to study the electronic structures and related electronic transitions of our GQDs, which reveals that their underlying carrier dynamics is strongly related to the chemical properties of aniline derivatives. Using these functionalized GQDs as lumophores, we fabricate light-emitting didoes (LEDs) that exhibit green, orange, and red electroluminescence that has high color purity. The maximum current efficiency of 3.47 cd A-1 and external quantum efficiency of 1.28% are recorded with our LEDs; these are the highest values ever reported for LEDs based on carbon-nanoparticle phosphors. This functionalization of GQDs with aniline derivatives represents a new method to fabricate LEDs that produce natural color.

Site-specific incorporation of probes into RNA polymerase by unnatural-amino-acid mutagenesis and Staudinger-Bertozzi ligation

PubMed Central

Chakraborty, Anirban; Mazumder, Abhishek; Lin, Miaoxin; Hasemeyer, Adam; Xu, Qumiao; Wang, Dongye; Ebright, Yon W.; Ebright, Richard H.

2015-01-01

Summary A three-step procedure comprising (i) unnatural-amino-acid mutagenesis with 4-azido-phenylalanine, (ii) Staudinger-Bertozzi ligation with a probe-phosphine derivative, and (iii) in vitro reconstitution of RNA polymerase (RNAP) enables the efficient site-specific incorporation of a fluorescent probe, a spin label, a crosslinking agent, a cleaving agent, an affinity tag, or any other biochemical or biophysical probe, at any site of interest in RNAP. Straightforward extensions of the procedure enable the efficient site-specific incorporation of two or more different probes in two or more different subunits of RNAP. We present protocols for synthesis of probe-phosphine derivatives, preparation of RNAP subunits and the transcription initiation factor σ, unnatural amino acid mutagenesis of RNAP subunits and σ, Staudinger ligation with unnatural-amino-acid-containing RNAP subunits and σ, quantitation of labelling efficiency and labelling specificity, and reconstitution of RNAP. PMID:25665560

Optimizing piezoelectric receivers for acoustic power transfer applications

NASA Astrophysics Data System (ADS)

Gorostiaga, M.; Wapler, M. C.; Wallrabe, U.

2018-07-01

In this paper, we aim to optimize piezoelectric plate receivers for acoustic power transfer applications by analyzing the influence of the losses and of the acoustic boundary conditions. We derive the analytic expressions of the efficiency of the receiver with the optimal electric loads attached, and analyze the maximum efficiency value and its frequency with different loss and acoustic boundary conditions. To validate the analytical expressions that we have derived, we perform experiments in water with composite transducers of different filling fractions, and see that a lower acoustic impedance mismatch can compensate the influence of large dielectric and acoustic losses to achieve a good performance. Finally, we briefly compare the advantages and drawbacks of composite transducers and pure PZT (lead zirconate titanate) plates as acoustic power receivers, and conclude that 1–3 composites can achieve similar efficiency values in low power applications due to their adjustable acoustic impedance.

Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 1: Executive summary. [using coal or coal derived fuels

NASA Technical Reports Server (NTRS)

Corman, J. C.

1976-01-01

A data base for the comparison of advanced energy conversion systems for utility applications using coal or coal-derived fuels was developed. Estimates of power plant performance (efficiency), capital cost, cost of electricity, natural resource requirements, and environmental intrusion characteristics were made for ten advanced conversion systems. Emphasis was on the energy conversion system in the context of a base loaded utility power plant. All power plant concepts were premised on meeting emission standard requirements. A steam power plant (3500 psig, 1000 F) with a conventional coal-burning furnace-boiler was analyzed as a basis for comparison. Combined cycle gas/steam turbine system results indicated competitive efficiency and a lower cost of electricity compared to the reference steam plant. The Open-Cycle MHD system results indicated the potential for significantly higher efficiency than the reference steam plant but with a higher cost of electricity.

Enhanced secretion of natto phytase by Bacillus subtilis.

PubMed

Tsuji, Shogo; Tanaka, Kosei; Takenaka, Shinji; Yoshida, Ken-ichi

2015-01-01

Phytases comprise a group of phosphatases that trim inorganic phosphates from phytic acid (IP6). In this study, we aimed to achieve the efficient secretion of phytase by Bacillus subtilis. B. subtilis laboratory standard strain 168 and its derivatives exhibit no phytase activity, whereas a natto starter secretes phytase actively. The natto phytase gene was cloned into strain RIK1285, a protease-defective derivative of 168, to construct a random library of its N-terminal fusions with 173 different signal peptides (SPs) identified in the 168 genome. The library was screened to assess the efficiency of phytase secretion based on clear zones around colonies on plates, which appeared when IP6 was hydrolyzed. The pbp SP enhanced the secretion of the natto phytase most efficiently, i.e. twice that of the original SP. Thus, the secreted natto phytase was purified and found to remove up to 3 phosphates from IP6.

Mesoporous nitrogen-doped carbon microfibers derived from Mg-biquinoline-dicarboxy compound for efficient oxygen electroreduction

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

Kong, Aiguo, E-mail: agkong@chem.ecnu.edu.cn; Fan, Xiaohong; Chen, Aoling

An in-situ MgO-templating synthesis route was introduced to obtain the mesoporous nitrogen-doped carbon microfibers by thermal conversion of new Mg-2,2′-biquinoline 4,4-dicarboxy acid coordination compound (Mg-DCA) microfibers. The investigated crystal structure of Mg-DCA testified that the assembling of Mg{sup 2+} and DCA through Mg-O coordination bond and hydrogen bond contributed to the formation of one-dimensional (1D) crystalline Mg-DCA microfibers. The nitrogen-doped carbons derived from the pyrolysis of Mg-DCA showed the well-defined microfiber morphology with high mesopore-surface area. Such mesoporous microfibers exhibited the efficient catalytic activity for oxygen reduction reaction (ORR) in alkaline solutions with better stability and methanol-tolerance performance. - Graphicalmore » abstract: Mesoporous nitrogen-doped carbon microfibers with efficient oxygen electroreduction activity were prepared by thermal conversion of new Mg-biquinoline-based coordination compound microfibers.« less

Comparative transcriptomic analysis of endothelial progenitor cells derived from umbilical cord blood and adult peripheral blood: Implications for the generation of induced pluripotent stem cells.

PubMed

Gao, Xiugong; Yourick, Jeffrey J; Sprando, Robert L

2017-12-01

Induced pluripotent stem cells (iPSCs) offer the potential to generate tissues with ethnic diversity enabling toxicity testing on selected populations. Recently, it has been reported that endothelial progenitor cells (EPCs) derived from umbilical cord blood (CB) or adult peripheral blood (PB) afford a practical and efficient cellular substrate for iPSC generation. However, differences between EPCs from different blood sources have rarely been studied. In the current study, we derived EPCs from blood mononuclear cells (MNCs) and reprogrammed EPCs into iPSCs. We also explored differences between CB-EPCs and PB-EPCs at the molecular and cellular levels through a combination of transcriptomic analysis and cell biology techniques. EPC colonies in CB-MNCs emerged 5-7days earlier, were 3-fold higher in number, and consistently larger in size than in PB-MNCs. Similarly, iPSC colonies generated from CB-EPCs was 2.5-fold higher in number than from PB-EPCs, indicating CB-EPCs have a higher reprogramming efficiency than PB-EPCs. Transcriptomic analysis using microarrays found a total of 1133 genes differentially expressed in CB-EPCs compared with PB-EPCs, with 675 genes upregulated and 458 downregulated. Several canonical pathways were impacted, among which the human embryonic stem cell pluripotency pathway was of particular interest. The differences in the gene expression pattern between CB-EPCs and PB-EPCs provide a molecular basis for the discrepancies seen in their derivation and reprogramming efficiencies, and highlight the advantages of using CB as the cellular source for the generation of iPSCs and their derivative tissues for ethnic-related toxicological applications. Published by Elsevier B.V.

Encapsidated Host Factors in Alphavirus Particles Influence Midgut Infection of Aedes aegypti.

PubMed

Mackenzie-Liu, David; Sokoloski, Kevin J; Purdy, Sarah; Hardy, Richard W

2018-05-16

Transmission of mosquito-borne viruses requires the efficient infection of both a permissive vertebrate host and a competent mosquito vector. The infectivity of Sindbis virus (SINV), the type species of the Alphavirus genus, is influenced by both the original and new host cell. We have shown that infection of vertebrate cells by SINV, chikungunya virus (CHIKV), and Ross River virus (RRV) produces two subpopulations of virus particles separable based on density. In contrast, a single population of viral particles is produced by mosquito cells. Previous studies demonstrated that the denser vertebrate-derived particles and the mosquito-derived particles contain components of the small subunit of the host cell ribosome, whereas the less dense vertebrate-derived particles do not. Infection of mice with RRV showed that both particle subpopulations are produced in an infected vertebrate, but in a tissue specific manner with serum containing only the less dense version of the virus particles. Previous infectivity studies using SINV particles have shown that the denser particles (SINV Heavy ) and mosquito derived particles SINV C6/36 are significantly more infectious in vertebrate cells than the less dense vertebrate derived particles (SINV Light ). The current study shows that SINV Light particles, initiate the infection of the mosquito midgut more efficiently than SINV Heavy particles and that this enhanced infectivity is associated with an exacerbated immune response to SINV Light infection in midgut tissues. The enhanced infection of SINV Light is specific to the midgut as intrathoracically injected virus do not exhibit the same fitness advantage. Together, our data indicate a biologically significant role for the SINV Light subpopulation in the efficient transmission from infected vertebrates to the mosquito vector.

Face-to-Face Packing of 2,3,9,10-Tetrasubstituted Pentacene Derivatives Revealed through a Solid State [4 + 4] Thermal Cycloaddition and Molecular Dynamic Simulation.

PubMed

Pal, Bikash; Lin, Bo-Chao; Dela Cerna, Mark Vincent Carreon; Hsu, Chao-Ping; Lin, Chih-Hsiu

2016-08-05

2,3,9,10-Substituted pentacene tetraesters and pentacene diester-dinitriles were synthesized. These pentacene derivatives underwent an unusual solid state [4 + 4] thermal dimerization with good efficiency and complete stereoselectivity. This observation indicates this series of pentacene derivatives adopt π-π stacking geometry with large mutual overlap in solid state. This notion was confirmed by molecualr dynamic simulation.

A Posteriori Finite Element Bounds for Sensitivity Derivatives of Partial-Differential-Equation Outputs. Revised

NASA Technical Reports Server (NTRS)

Lewis, Robert Michael; Patera, Anthony T.; Peraire, Jaume

1998-01-01

We present a Neumann-subproblem a posteriori finite element procedure for the efficient and accurate calculation of rigorous, 'constant-free' upper and lower bounds for sensitivity derivatives of functionals of the solutions of partial differential equations. The design motivation for sensitivity derivative error control is discussed; the a posteriori finite element procedure is described; the asymptotic bounding properties and computational complexity of the method are summarized; and illustrative numerical results are presented.

Rate constants of chemical reactions from semiclassical transition state theory in full and one dimension.

PubMed

Greene, Samuel M; Shan, Xiao; Clary, David C

2016-06-28

Semiclassical Transition State Theory (SCTST), a method for calculating rate constants of chemical reactions, offers gains in computational efficiency relative to more accurate quantum scattering methods. In full-dimensional (FD) SCTST, reaction probabilities are calculated from third and fourth potential derivatives along all vibrational degrees of freedom. However, the computational cost of FD SCTST scales unfavorably with system size, which prohibits its application to larger systems. In this study, the accuracy and efficiency of 1-D SCTST, in which only third and fourth derivatives along the reaction mode are used, are investigated in comparison to those of FD SCTST. Potential derivatives are obtained from numerical ab initio Hessian matrix calculations at the MP2/cc-pVTZ level of theory, and Richardson extrapolation is applied to improve the accuracy of these derivatives. Reaction barriers are calculated at the CCSD(T)/cc-pVTZ level. Results from FD SCTST agree with results from previous theoretical and experimental studies when Richardson extrapolation is applied. Results from our implementation of 1-D SCTST, which uses only 4 single-point MP2/cc-pVTZ energy calculations in addition to those for conventional TST, agree with FD results to within a factor of 5 at 250 K. This degree of agreement and the efficiency of the 1-D method suggest its potential as a means of approximating rate constants for systems too large for existing quantum scattering methods.

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

Efficient Generation of Gene-Modified Pigs Harboring Precise Orthologous Human Mutation via CRISPR/Cas9-Induced Homology-Directed Repair in Zygotes.

PubMed

Zhou, Xiaoyang; Wang, Lulu; Du, Yinan; Xie, Fei; Li, Liang; Liu, Yu; Liu, Chuanhong; Wang, Shiqiang; Zhang, Shibing; Huang, Xingxu; Wang, Yong; Wei, Hong

2016-01-01

Precise genetic mutation of model animals is highly valuable for functional investigation of human mutations. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9)-induced homology-directed repair (HDR) is usually used for precise genetic mutation, being limited by the relatively low efficiency compared with that of non-homologous end joining (NHEJ). Although inhibition of NHEJ was shown to enhance HDR-derived mutation, in this work, without inhibition of NHEJ, we first generated gene-modified pigs harboring precise orthologous human mutation (Sox10 c.A325>T) via CRISPR/Cas9-induced HDR in zygotes using single-strand oligo DNA (ssODN) as template with an efficiency as high as 80%, indicating that pig zygotes exhibited high activities of HDR relative to NHEJ and were highly amendable to genetic mutation via CIRSPR/Cas9-induced HDR. Besides, we found a higher concentration of ssODN remarkably reduced HDR-derived mutation in pig zygotes, suggesting a possible balance for optimal HDR-derived mutation in zygotes between the excessive accessibility to HDR templates and the activities of HDR relative to NHEJ which appeared to be negatively correlated to ssODN concentration. In addition, the HDR-derived mutation, as well as those from NHEJ, extensively integrated into various tissues including gonad of founder pig without detected off-targeting, suggesting CRISPR/Cas9-induced HDR in zygotes is a reliable approach for precise genetic mutation in pigs. © 2015 WILEY PERIODICALS, INC.

A small and efficient dimerization/packaging signal of rat VL30 RNA and its use in murine leukemia virus-VL30-derived vectors for gene transfer.

PubMed

Torrent, C; Gabus, C; Darlix, J L

1994-02-01

Retroviral genomes consist of two identical RNA molecules associated at their 5' ends by the dimer linkage structure located in the packaging element (Psi or E) necessary for RNA dimerization in vitro and packaging in vivo. In murine leukemia virus (MLV)-derived vectors designed for gene transfer, the Psi + sequence of 600 nucleotides directs the packaging of recombinant RNAs into MLV virions produced by helper cells. By using in vitro RNA dimerization as a screening system, a sequence of rat VL30 RNA located next to the 5' end of the Harvey mouse sarcoma virus genome and as small as 67 nucleotides was found to form stable dimeric RNA. In addition, a purine-rich sequence located at the 5' end of this VL30 RNA seems to be critical for RNA dimerization. When this VL30 element was extended by 107 nucleotides at its 3' end and inserted into an MLV-derived vector lacking MLV Psi +, it directed the efficient encapsidation of recombinant RNAs into MLV virions. Because this VL30 packaging signal is smaller and more efficient in packaging recombinant RNAs than the MLV Psi + and does not contain gag or glyco-gag coding sequences, its use in MLV-derived vectors should render even more unlikely recombinations which could generate replication-competent viruses. Therefore, utilization of the rat VL30 packaging sequence should improve the biological safety of MLV vectors for human gene transfer.

Robust Differentiation of mRNA-Reprogrammed Human Induced Pluripotent Stem Cells Toward a Retinal Lineage.

PubMed

Sridhar, Akshayalakshmi; Ohlemacher, Sarah K; Langer, Kirstin B; Meyer, Jason S

2016-04-01

The derivation of human induced pluripotent stem cells (hiPSCs) from patient-specific sources has allowed for the development of novel approaches to studies of human development and disease. However, traditional methods of generating hiPSCs involve the risks of genomic integration and potential constitutive expression of pluripotency factors and often exhibit low reprogramming efficiencies. The recent description of cellular reprogramming using synthetic mRNA molecules might eliminate these shortcomings; however, the ability of mRNA-reprogrammed hiPSCs to effectively give rise to retinal cell lineages has yet to be demonstrated. Thus, efforts were undertaken to test the ability and efficiency of mRNA-reprogrammed hiPSCs to yield retinal cell types in a directed, stepwise manner. hiPSCs were generated from human fibroblasts via mRNA reprogramming, with parallel cultures of isogenic human fibroblasts reprogrammed via retroviral delivery of reprogramming factors. New lines of mRNA-reprogrammed hiPSCs were established and were subsequently differentiated into a retinal fate using established protocols in a directed, stepwise fashion. The efficiency of retinal differentiation from these lines was compared with retroviral-derived cell lines at various stages of development. On differentiation, mRNA-reprogrammed hiPSCs were capable of robust differentiation to a retinal fate, including the derivation of photoreceptors and retinal ganglion cells, at efficiencies often equal to or greater than their retroviral-derived hiPSC counterparts. Thus, given that hiPSCs derived through mRNA-based reprogramming strategies offer numerous advantages owing to the lack of genomic integration or constitutive expression of pluripotency genes, such methods likely represent a promising new approach for retinal stem cell research, in particular, those for translational applications. In the current report, the ability to derive mRNA-reprogrammed human induced pluripotent stem cells (hiPSCs), followed by the differentiation of these cells toward a retinal lineage, including photoreceptors, retinal ganglion cells, and retinal pigment epithelium, has been demonstrated. The use of mRNA reprogramming to yield pluripotency represents a unique ability to derive pluripotent stem cells without the use of DNA vectors, ensuring the lack of genomic integration and constitutive expression. The studies reported in the present article serve to establish a more reproducible system with which to derive retinal cell types from hiPSCs through the prevention of genomic integration of delivered genes and should also eliminate the risk of constitutive expression of these genes. Such ability has important implications for the study of, and development of potential treatments for, retinal degenerative disorders and the development of novel therapeutic approaches to the treatment of these diseases. ©AlphaMed Press.

Optimization of fiber grating couplers on SOI using advanced search algorithms.

PubMed

Wohlfeil, Benjamin; Zimmermann, Lars; Petermann, Klaus

2014-06-01

A one-dimensional fiber grating coupler is derived from a waveguide with random etches using implementations of particle swarm and genetic algorithms. The resulting gratings yield a theoretical coupling efficiency of up to 1.1 dB and prompt clear design rules for the layout of highly efficient fiber grating couplers.

VirusDetect: An automated pipeline for efficient virus discovery using deep sequencing of small RNAs

USDA-ARS?s Scientific Manuscript database

Accurate detection of viruses in plants and animals is critical for agriculture production and human health. Deep sequencing and assembly of virus-derived siRNAs has proven to be a highly efficient approach for virus discovery. However, to date no computational tools specifically designed for both k...

Clash of the Titans: Comparing productivity via radiation use efficiency for two grass giants of the biofuel field

USDA-ARS?s Scientific Manuscript database

The comparative productivity of switchgrass (Panicum virgatum L.) and Miscanthus (Miscanthus x giganteus) is of critical importance to the biofuel industry. The radiation use efficiency (RUE), when derived in an environment with non-limiting soil water and soil nutrients, provides one metric of re...

Improved design of a tangential entry cyclone separator for separation of particles from exhaust gas of diesel engine.

PubMed

Mukhopadhyay, N

2011-01-01

An effective design of cyclone separator with tangential inlet is developed applying an equation derived from the correlation of collection efficiency with maximum pressure drop components of the cyclone, which can efficiently remove the particles around 1microm of the exhaust gas of diesel engine.

Enhancement of mercury capture by the simultaneous addition of hydrogen bromide (HBr) and fly ashes in a slipstream facility.

PubMed

Cao, Yan; Wang, Quan-Hai; Li, Jun; Cheng, Jen-Chieh; Chan, Chia-Chun; Cohron, Marten; Pan, Wei-Ping

2009-04-15

Low halogen content in tested Powder River Basin (PRB) coals and low loss of ignition content (LOI) in PRB-derived fly ash were likely responsible for higher elemental mercury content (averaging about 75%) in the flue gas and also lower mercury capture efficiency by electrostatic precipitator (ESP) and wet-FGD. To develop a cost-effective approach to mercury capture in a full-scale coal-fired utility boiler burning PRB coal, experiments were conducted adding hydrogen bromide (HBr) or simultaneously adding HBr and selected fly ashes in a slipstream reactor (0.152 x 0.152 m) under real flue gas conditions. The residence time of the flue gas inside the reactorwas about 1.4 s. The average temperature of the slipstream reactor was controlled at about 155 degrees C. Tests were organized into two phases. In Phase 1, only HBr was added to the slipstream reactor, and in Phase 2, HBr and selected fly ash were added simultaneously. HBr injection was effective (>90%) for mercury oxidation at a low temperature (155 degrees C) with an HBr addition concentration of about 4 ppm in the flue gas. Additionally, injected HBr enhanced mercury capture by PRB fly ash in the low-temperature range. The mercury capture efficiency, attesting conditions of the slipstream reactor, reached about 50% at an HBr injection concentration of 4 ppm in the flue gas. Compared to only the addition of HBr, simultaneously adding bituminous-derived fly ash in a minimum amount (30 lb/MMacf), together with HBr injection at 4 ppm, could increase mercury capture efficiency by 30%. Injection of lignite-derived fly ash at 30 lb/MMacf could achieve even higher mercury removal efficiency (an additional 35% mercury capture efficiency compared to HBr addition alone).

Comparison of numerical techniques for integration of stiff ordinary differential equations arising in combustion chemistry

NASA Technical Reports Server (NTRS)

Radhakrishnan, K.

1984-01-01

The efficiency and accuracy of several algorithms recently developed for the efficient numerical integration of stiff ordinary differential equations are compared. The methods examined include two general-purpose codes, EPISODE and LSODE, and three codes (CHEMEQ, CREK1D, and GCKP84) developed specifically to integrate chemical kinetic rate equations. The codes are applied to two test problems drawn from combustion kinetics. The comparisons show that LSODE is the fastest code currently available for the integration of combustion kinetic rate equations. An important finding is that an interactive solution of the algebraic energy conservation equation to compute the temperature does not result in significant errors. In addition, this method is more efficient than evaluating the temperature by integrating its time derivative. Significant reductions in computational work are realized by updating the rate constants (k = at(supra N) N exp(-E/RT) only when the temperature change exceeds an amount delta T that is problem dependent. An approximate expression for the automatic evaluation of delta T is derived and is shown to result in increased efficiency.

Second-law efficiency of solar-thermal cavity receivers

NASA Technical Reports Server (NTRS)

Moynihan, P. I.

1983-01-01

Properly quantified performance of a solar-thermal cavity receiver must not only account for the energy gains and losses as dictated by the First Law of thermodynamics, but it must also account for the quality of that energy. However, energy quality can only be determined from the Second Law. An equation for the Second Law efficiency of a cavity receiver is derived from the definition of available energy, which is a thermodynamic property that measures the maximum amount of work obtainable when a system is allowed to come into unrestrained equilibrium with the surrounding environment. The fundamental concepts of the entropy and availability of radiation were explored from which a workable relationship among the reflected cone half-angle, the insolation, and the concentrator geometric characteristics was developed as part of the derivation of the Second Law efficiency. First and Second Law efficiencies were compared for data collected from two receivers that were designed for different purposes. A Second Law approach to quantifying the performance of a solar-thermal cavity receiver lends greater insight into the total performance than does the conventional First Law method.

Dynamical Origin of Highly Efficient Energy Dissipation in Soft Magnetic Nanoparticles for Magnetic Hyperthermia Applications

NASA Astrophysics Data System (ADS)

Kim, Min-Kwan; Sim, Jaegun; Lee, Jae-Hyeok; Kim, Miyoung; Kim, Sang-Koog

2018-05-01

We explore robust magnetization-dynamic behaviors in soft magnetic nanoparticles in single-domain states and find their related high-efficiency energy-dissipation mechanism using finite-element micromagnetic simulations. We also make analytical derivations that provide deeper physical insights into the magnetization dynamics associated with Gilbert damping parameters under applications of time-varying rotating magnetic fields of different strengths and frequencies and static magnetic fields. Furthermore, we find that the mass-specific energy-dissipation rate at resonance in the steady-state regime changes remarkably with the strength of rotating fields and static fields for given damping constants. The associated magnetization dynamics are well interpreted with the help of the numerical calculation of analytically derived explicit forms. The high-efficiency energy-loss power can be obtained using soft magnetic nanoparticles in the single-domain state by tuning the frequency of rotating fields to the resonance frequency; what is more, it is controllable via the rotating and static field strengths for a given intrinsic damping constant. We provide a better and more efficient means of achieving specific loss power that can be implemented in magnetic hyperthermia applications.

Human serum-derived protein removes the need for coating in defined human pluripotent stem cell culture

PubMed Central

Pijuan-Galitó, Sara; Tamm, Christoffer; Schuster, Jens; Sobol, Maria; Forsberg, Lars; Merry, Catherine L. R.; Annerén, Cecilia

2016-01-01

Reliable, scalable and time-efficient culture methods are required to fully realize the clinical and industrial applications of human pluripotent stem (hPS) cells. Here we present a completely defined, xeno-free medium that supports long-term propagation of hPS cells on uncoated tissue culture plastic. The medium consists of the Essential 8 (E8) formulation supplemented with inter-α-inhibitor (IαI), a human serum-derived protein, recently demonstrated to activate key pluripotency pathways in mouse PS cells. IαI efficiently induces attachment and long-term growth of both embryonic and induced hPS cell lines when added as a soluble protein to the medium at seeding. IαI supplementation efficiently supports adaptation of feeder-dependent hPS cells to xeno-free conditions, clonal growth as well as single-cell survival in the absence of Rho-associated kinase inhibitor (ROCKi). This time-efficient and simplified culture method paves the way for large-scale, high-throughput hPS cell culture, and will be valuable for both basic research and commercial applications. PMID:27405751

An efficient and scalable pipeline for epitope tagging in mammalian stem cells using Cas9 ribonucleoprotein

PubMed Central

Dewari, Pooran Singh; Southgate, Benjamin; Mccarten, Katrina; Monogarov, German; O'Duibhir, Eoghan; Quinn, Niall; Tyrer, Ashley; Leitner, Marie-Christin; Plumb, Colin; Kalantzaki, Maria; Blin, Carla; Finch, Rebecca; Bressan, Raul Bardini; Morrison, Gillian; Jacobi, Ashley M; Behlke, Mark A; von Kriegsheim, Alex; Tomlinson, Simon; Krijgsveld, Jeroen

2018-01-01

CRISPR/Cas9 can be used for precise genetic knock-in of epitope tags into endogenous genes, simplifying experimental analysis of protein function. However, Cas9-assisted epitope tagging in primary mammalian cell cultures is often inefficient and reliant on plasmid-based selection strategies. Here, we demonstrate improved knock-in efficiencies of diverse tags (V5, 3XFLAG, Myc, HA) using co-delivery of Cas9 protein pre-complexed with two-part synthetic modified RNAs (annealed crRNA:tracrRNA) and single-stranded oligodeoxynucleotide (ssODN) repair templates. Knock-in efficiencies of ~5–30%, were achieved without selection in embryonic stem (ES) cells, neural stem (NS) cells, and brain-tumor-derived stem cells. Biallelic-tagged clonal lines were readily derived and used to define Olig2 chromatin-bound interacting partners. Using our novel web-based design tool, we established a 96-well format pipeline that enabled V5-tagging of 60 different transcription factors. This efficient, selection-free and scalable epitope tagging pipeline enables systematic surveys of protein expression levels, subcellular localization, and interactors across diverse mammalian stem cells. PMID:29638216

Unusual Features of Sodium Taurocholate Cotransporting Polypeptide as a Hepatitis B Virus Receptor

PubMed Central

Zong, Li; Sureau, Camille; Barker, Luke; Wands, Jack R.; Tong, Shuping

2016-01-01

ABSTRACT Cell culture (cc)-derived hepatitis B virus (HBV) can infect differentiated HepaRG cells, but efficient infection requires addition of polyethylene glycol (PEG) during inoculation. Identification of sodium taurocholate cotransporting polypeptide (NTCP) as an HBV receptor enabled ccHBV infection of NTCP reconstituted HepG2 cells, although very little hepatitis B surface antigen (HBsAg) is produced. We found infection by patient serum-derived HBV (sHBV), which required purification of viral particles through ultracentrifugation or PEG precipitation, was PEG independent and much more efficient in HepaRG cells than in HepG2/NTCP cells. In contrast to hepatitis B e antigen (HBeAg), HBsAg was not a reliable marker of productive sHBV infection at early time points. A low HBsAg/HBeAg ratio by ccHBV-infected HepG2/NTCP cells was attributable to dimethyl sulfoxide (DMSO) in culture medium, NTCP overexpression, and HBV genotype D. HepG2/NTCP cells released more viral antigens than HepG2 cells after HBV genome delivery by adeno-associated virus, and stable expression of NTCP in a ccHBV producing cell line increased viral mRNAs, proteins, replicative DNA, and covalently closed circular DNA. NTCP protein expression in HepG2/NTCP cells, despite being driven by the cytomegalovirus promoter, was markedly increased by DMSO treatment. This at least partly explains ability of DMSO to promote ccHBV infection in such cell lines. In conclusion, NTCP appeared inefficient to mediate infection by serum-derived HBV. It could promote HBV RNA transcription while inhibiting HBsAg secretion. Efficient PEG-independent sHBV infection of HepaRG cells permits comparative studies of diverse clinical HBV isolates and will help identify additional factors on virion surface promoting attachment to hepatocytes. IMPORTANCE Currently in vitro infection with hepatitis B virus (HBV) depends on cell culture-derived HBV inoculated in the presence of polyethylene glycol. We found patient serum-derived HBV could efficiently infect differentiated HepaRG cells independent of polyethylene glycol, which represents a more physiological infection system. Serum-derived HBV has poor infectivity in HepG2 cells reconstituted with sodium taurocholate cotransporting polypeptide (NTCP), the currently accepted HBV receptor. Moreover, HepG2/NTCP cells secreted very little hepatitis B surface antigen after infection with cell culture-derived HBV, which was attributed to NTCP overexpression, genotype D virus, and dimethyl sulfoxide added to culture medium. NTCP could promote HBV RNA transcription, protein expression, and DNA replication in HepG2 cells stably transfected with HBV DNA, while dimethyl sulfoxide could increase NTCP protein level despite transcriptional control by a cytomegalovirus promoter. Therefore, this study revealed several unusual features of NTCP as an HBV receptor and established conditions for efficient serum virus infection in vitro. PMID:27384660

Efficient synthesis of a fluorine-18 labeled biotin derivative.

PubMed

Claesener, Michael; Breyholz, Hans-Jörg; Hermann, Sven; Faust, Andreas; Wagner, Stefan; Schober, Otmar; Schäfers, Michael; Kopka, Klaus

2012-11-01

The natural occurring vitamin biotin, also known as vitamin H or vitamin B(7), plays a major role in various metabolic reactions. Caused by its high binding affinity to the protein avidin with a dissociation constant of about 10(-15)M the biotin-avidin system was extensively examined for multiple applications. We have synthesized a fluorine-18 labeled biotin derivative [(18)F]4 for a potential application in positron emission tomography (PET). Mesylate precursor 3 was obtained by an efficient two-step reaction via a copper catalyzed azide-alkyne cycloaddition (CuAAC) from easily accessible starting materials. [(18)F]4 was successfully synthesized by a nucleophilic radiofluorination of precursor 3. A biodistribution study by means of small-animal PET imaging in wt-mice was performed and serum stability was examined. Compound [(18)F]4 was obtained from precursor compound 3 with an average specific activity of 16GBq/μmol within 45min and a radiochemical yield of 45±5% (decay corrected). [(18)F]4 demonstrated only negligible decomposition in human serum. A qualitative binding study revealed the high affinity of the synthesized biotin derivative to avidin. Blocking experiments with native biotin showed that binding was site-specific. Biodistribution studies showed that [(18)F]4 was cleared quickly and efficiently from the body by hepatobiliary and renal elimination. An efficient synthesis for [(18)F]4 was established. In vivo characteristics were determined and demonstrated the pharmacokinetic behaviour of [(18)F]4. Copyright © 2012 Elsevier Inc. All rights reserved.

Cholesterol derived cationic lipids as potential non-viral gene delivery vectors and their serum compatibility.

PubMed

Ju, Jia; Huan, Meng-Lei; Wan, Ning; Hou, Yi-Lin; Ma, Xi-Xi; Jia, Yi-Yang; Li, Chen; Zhou, Si-Yuan; Zhang, Bang-Le

2016-05-15

Cholesterol derivatives M1-M6 as synthetic cationic lipids were designed and the biological evaluation of the cationic liposomes based on them as non-viral gene delivery vectors were described. Plasmid pEGFP-N1, used as model gene, was transferred into 293T cells by cationic liposomes formed with M1-M6 and transfection efficiency and GFP expression were tested. Cationic liposomes prepared with cationic lipids M1-M6 exhibited good transfection activity, and the transfection activity was parallel (M2 and M4) or superior (M1 and M6) to that of DC-Chol derived from the same backbone. Among them, the transfection efficiency of cationic lipid M6 was parallel to that of the commercially available Lipofectamine2000. The optimal formulation of M1 and M6 were found to be at a mol ratio of 1:0.5 for cationic lipid/DOPE, and at a N/P charge mol ratio of 3:1 for liposome/DNA. Under optimized conditions, the efficiency of M1 and M6 is greater than that of all the tested commercial liposomes DC-Chol and Lipofectamine2000, even in the presence of serum. The results indicated that M1 and M6 exhibited low cytotoxicity, good serum compatibility and efficient transfection performance, having the potential of being excellent non-viral vectors for gene delivery. Copyright © 2016 Elsevier Ltd. All rights reserved.

Maximum efficiency of ideal heat engines based on a small system: correction to the Carnot efficiency at the nanoscale.

PubMed

Quan, H T

2014-06-01

We study the maximum efficiency of a heat engine based on a small system. It is revealed that due to the finiteness of the system, irreversibility may arise when the working substance contacts with a heat reservoir. As a result, there is a working-substance-dependent correction to the Carnot efficiency. We derive a general and simple expression for the maximum efficiency of a Carnot cycle heat engine in terms of the relative entropy. This maximum efficiency approaches the Carnot efficiency asymptotically when the size of the working substance increases to the thermodynamic limit. Our study extends Carnot's result of the maximum efficiency to an arbitrary working substance and elucidates the subtlety of thermodynamic laws in small systems.

Thermodynamic limits of energy harvesting from outgoing thermal radiation.

PubMed

Buddhiraju, Siddharth; Santhanam, Parthiban; Fan, Shanhui

2018-04-17

We derive the thermodynamic limits of harvesting power from the outgoing thermal radiation from the ambient to the cold outer space. The derivations are based on a duality relation between thermal engines that harvest solar radiation and those that harvest outgoing thermal radiation. In particular, we derive the ultimate limit for harvesting outgoing thermal radiation, which is analogous to the Landsberg limit for solar energy harvesting, and show that the ultimate limit far exceeds what was previously thought to be possible. As an extension of our work, we also derive the ultimate limit of efficiency of thermophotovoltaic systems.

On the Achievable Throughput Over TVWS Sensor Networks

PubMed Central

Caleffi, Marcello; Cacciapuoti, Angela Sara

2016-01-01

In this letter, we study the throughput achievable by an unlicensed sensor network operating over TV white space spectrum in presence of coexistence interference. Through the letter, we first analytically derive the achievable throughput as a function of the channel ordering. Then, we show that the problem of deriving the maximum expected throughput through exhaustive search is computationally unfeasible. Finally, we derive a computational-efficient algorithm characterized by polynomial-time complexity to compute the channel set maximizing the expected throughput and, stemming from this, we derive a closed-form expression of the maximum expected throughput. Numerical simulations validate the theoretical analysis. PMID:27043565

Adenovirus Virus-Associated RNAII-Derived Small RNAs Are Efficiently Incorporated into the RNA-Induced Silencing Complex and Associate with Polyribosomes▿ §

PubMed Central

Xu, Ning; Segerman, Bo; Zhou, Xiaofu; Akusjärvi, Göran

2007-01-01

Adenovirus type 5 encodes two highly structured short RNAs, the virus-associated (VA) RNAI and RNAII. Both are processed by Dicer into small RNAs that are incorporated into the RNA-induced silencing complex (RISC). We show here, by cloning of small RNAs, that approximately 80% of Ago2-containing RISC immunopurified from late-infected cells is associated with VA RNA-derived small RNAs (mivaRNAs). Most surprisingly, VA RNAII, which is expressed at 20-fold lower levels compared to that of VA RNAI, appears to be the preferred substrate for Dicer and accounts for approximately 60% of all small RNAs in RISC. The mivaRNAs are derived from the 3′ strand of the terminal stems of the VA RNAs, with the major fraction of VA RNAII starting at position 138. The small RNAs derived from VA RNAI were more heterogeneous in size, with the two predominant small RNAs starting at positions 137 and 138. Collectively, our results suggest that the mivaRNAs are efficiently used for RISC assembly in late-infected cells. Potentially, they function as miRNAs, regulating translation of cellular mRNAs. In support of this hypothesis, we detected a fraction of the VA RNAII-derived mivaRNAs on polyribosomes. PMID:17652395

Adenovirus virus-associated RNAII-derived small RNAs are efficiently incorporated into the rna-induced silencing complex and associate with polyribosomes.

PubMed

Xu, Ning; Segerman, Bo; Zhou, Xiaofu; Akusjärvi, Göran

2007-10-01

Adenovirus type 5 encodes two highly structured short RNAs, the virus-associated (VA) RNAI and RNAII. Both are processed by Dicer into small RNAs that are incorporated into the RNA-induced silencing complex (RISC). We show here, by cloning of small RNAs, that approximately 80% of Ago2-containing RISC immunopurified from late-infected cells is associated with VA RNA-derived small RNAs (mivaRNAs). Most surprisingly, VA RNAII, which is expressed at 20-fold lower levels compared to that of VA RNAI, appears to be the preferred substrate for Dicer and accounts for approximately 60% of all small RNAs in RISC. The mivaRNAs are derived from the 3' strand of the terminal stems of the VA RNAs, with the major fraction of VA RNAII starting at position 138. The small RNAs derived from VA RNAI were more heterogeneous in size, with the two predominant small RNAs starting at positions 137 and 138. Collectively, our results suggest that the mivaRNAs are efficiently used for RISC assembly in late-infected cells. Potentially, they function as miRNAs, regulating translation of cellular mRNAs. In support of this hypothesis, we detected a fraction of the VA RNAII-derived mivaRNAs on polyribosomes.

Iron Oxide-Supported Copper Oxide Nanoparticles (Nanocat-Fe-CuO): Magnetically Recyclable Catalysts for the Synthesis of Pyrazole Derivatives, 4-Methoxyaniline, and Ullmann-type Condensation Reactions

EPA Science Inventory

An efficient and benign protocol is reported for the synthesis of 4-methoxyaniline, medicinally important pyrazole derivatives, and Ullmann-type condensation reaction using magnetically separable and reusable magnetite-supported copper (nanocat-Fe-CuO) nanoparticles under mild co...

Optimizing Experimental Designs Relative to Costs and Effect Sizes.

ERIC Educational Resources Information Center

Headrick, Todd C.; Zumbo, Bruno D.

A general model is derived for the purpose of efficiently allocating integral numbers of units in multi-level designs given prespecified power levels. The derivation of the model is based on a constrained optimization problem that maximizes a general form of a ratio of expected mean squares subject to a budget constraint. This model provides more…

Study of Adaptive Mathematical Models for Deriving Automated Pilot Performance Measurement Techniques. Volume I. Model Development.

ERIC Educational Resources Information Center

Connelly, Edward A.; And Others

A new approach to deriving human performance measures and criteria for use in automatically evaluating trainee performance is documented in this report. The ultimate application of the research is to provide methods for automatically measuring pilot performance in a flight simulator or from recorded in-flight data. An efficient method of…

Study of Adaptive Mathematical Models for Deriving Automated Pilot Performance Measurement Techniques. Volume II. Appendices. Final Report.

ERIC Educational Resources Information Center

Connelly, E. M.; And Others

A new approach to deriving human performance measures and criteria for use in automatically evaluating trainee performance is described. Ultimately, this approach will allow automatic measurement of pilot performance in a flight simulator or from recorded in-flight data. An efficient method of representing performance data within a computer is…

Fisher classifier and its probability of error estimation

NASA Technical Reports Server (NTRS)

Chittineni, C. B.

1979-01-01

Computationally efficient expressions are derived for estimating the probability of error using the leave-one-out method. The optimal threshold for the classification of patterns projected onto Fisher's direction is derived. A simple generalization of the Fisher classifier to multiple classes is presented. Computational expressions are developed for estimating the probability of error of the multiclass Fisher classifier.

Pyrrolidinones derived from (S)-pyroglutamic acid: penmacric acid and analogues.

PubMed

Anwar, Muhammed; Bailey, Jonathan H; Dickinson, Laura C; Edwards, Hermia J; Goswami, Rajesh; Moloney, Mark G

2003-07-07

Alkylation reactions using alpha-halolactams or lactam enolates derived from bicyclic lactam templates can proceed with high endo- or exo- diastereoselectivity respectively. In the latter case, stereochemical correction by means of enolate generation and hindered phenol quench is possible with moderate efficiency. This protocol has been applied to the synthesis of protected penmacric acid and its analogues.

Mononuclear Copper Complex Catalyzed Four-Electron Reduction of Oxygen

PubMed Central

Fukuzumi, Shunichi; Kotani, Hiroaki; Lucas, Heather R.; Doi, Kaoru; Suenobu, Tomoyoshi; Peterson, Ryan L.; Karlin, Kenneth D.

2010-01-01

A mononuclear CuII complex acts as an efficient catalyst for four-electron reduction of O2 to H2O by a ferrocene derivative via formation of the dinuclear CuII peroxo complex that is further reduced in the presence of protons by a ferrocene derivative to regenerate the CuII complex. PMID:20443560

Efficiency of unconstrained minimization techniques in nonlinear analysis

NASA Technical Reports Server (NTRS)

Kamat, M. P.; Knight, N. F., Jr.

1978-01-01

Unconstrained minimization algorithms have been critically evaluated for their effectiveness in solving structural problems involving geometric and material nonlinearities. The algorithms have been categorized as being zeroth, first, or second order depending upon the highest derivative of the function required by the algorithm. The sensitivity of these algorithms to the accuracy of derivatives clearly suggests using analytically derived gradients instead of finite difference approximations. The use of analytic gradients results in better control of the number of minimizations required for convergence to the exact solution.

Selective hydroxylation of benzene derivatives and alkanes with hydrogen peroxide catalysed by a manganese complex incorporated into mesoporous silica-alumina.

PubMed

Aratani, Yusuke; Yamada, Yusuke; Fukuzumi, Shunichi

2015-03-18

Selective hydroxylation of benzene derivatives and alkanes to the corresponding phenol and alcohol derivatives with hydrogen peroxide was efficiently catalysed by a manganese tris(2-pyridylmethyl)amine (tpa) complex ([(tpa)Mn(II)](2+)) incorporated into mesoporous silica-alumina with highly acidic surfaces in contrast to the reactions in a homogeneous solution where [(tpa)Mn(II)](2+) was converted catalytically to a much less active bis(μ-oxo)dimanganese(III,IV) complex.

On analytic design of loudspeaker arrays with uniform radiation characteristics

PubMed

Aarts; Janssen

2000-01-01

Some notes on analytical derived loudspeaker arrays with uniform radiation characteristics are presented. The array coefficients are derived via analytical means and compared with so-called maximal flat sequences known from telecommunications and information theory. It appears that the newly derived array, i.e., the quadratic phase array, has a higher efficiency than the Bessel array and a flatter response than the Barker array. The method discussed admits generalization to the design of arrays with desired nonuniform radiating characteristics.

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

Efficient synthesis of new 2,3-dihydrooxazole-spirooxindoles hybrids as antimicrobial agents.

PubMed

Tiwari, Shailendra; Pathak, Poonam; Sagar, Ram

2016-05-15

Two series of new 2,3-dihydrooxazole-spirooxindole derivatives were efficiently synthesized starting from N'-(2-oxoindolin-3-ylidene) benzohydrazide/N'-(2-oxoindolin-3-ylidene)-2-phenoxyacetohydrazide using designed synthetic route. Newly synthesized 2,3-dihydrooxazole-spirooxindole derivatives were screened for their antibacterial and antifungal activity against different pathogenic strain of bacteria and fungi. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) were determined for the test compounds as well as for reference standards. Compounds 4e, 4g, 7g have shown good antibacterial activity whereas compounds 4f, 7b, 7d have displayed better antifungal activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heteroleptic Copper(I)-Based Complexes for Photocatalysis: Combinatorial Assembly, Discovery, and Optimization.

PubMed

Minozzi, Clémentine; Caron, Antoine; Grenier-Petel, Jean-Christophe; Santandrea, Jeffrey; Collins, Shawn K

2018-05-04

A library of 50 copper-based complexes derived from bisphosphines and diamines was prepared and evaluated in three mechanistically distinct photocatalytic reactions. In all cases, a copper-based catalyst was identified to afford high yields, where new heteroleptic complexes derived from the bisphosphine BINAP displayed high efficiency across all reaction types. Importantly, the evaluation of the library of copper complexes revealed that even when photophysical data is available, it is not always possible to predict which catalyst structure will be efficient or inefficient in a given process, emphasizing the advantages for catalyst structures with high modularity and structural variability. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

New numerical approximation of fractional derivative with non-local and non-singular kernel: Application to chaotic models

NASA Astrophysics Data System (ADS)

Toufik, Mekkaoui; Atangana, Abdon

2017-10-01

Recently a new concept of fractional differentiation with non-local and non-singular kernel was introduced in order to extend the limitations of the conventional Riemann-Liouville and Caputo fractional derivatives. A new numerical scheme has been developed, in this paper, for the newly established fractional differentiation. We present in general the error analysis. The new numerical scheme was applied to solve linear and non-linear fractional differential equations. We do not need a predictor-corrector to have an efficient algorithm, in this method. The comparison of approximate and exact solutions leaves no doubt believing that, the new numerical scheme is very efficient and converges toward exact solution very rapidly.

Efficiency of aerosol collection on wires exposed in the stratosphere

NASA Technical Reports Server (NTRS)

Lem, H. Y.; Farlow, N. H.

1979-01-01

The theory of inertial impaction is briefly presented. Stratospheric aerosol research experiments were performed duplicating Wong et al. experiments. The use of the curve of inertial parameters vs particle collection efficiency, derived from Wong et al., was found to be justified. The results show that stratospheric aerosol particles of all sizes are collectible by wire impaction technique. Curves and tables are presented and used to correct particle counts for collection efficiencies less than 100%.

A concept for a fuel efficient flight planning aid for general aviation

NASA Technical Reports Server (NTRS)

Collins, B. P.; Haines, A. L.; Wales, C. J.

1982-01-01

A core equation for estimation of fuel burn from path profile data was developed. This equation was used as a necessary ingredient in a dynamic program to define a fuel efficient flight path. The resultant algorithm is oriented toward use by general aviation. The pilot provides a description of the desired ground track, standard aircraft parameters, and weather at selected waypoints. The algorithm then derives the fuel efficient altitudes and velocities at the waypoints.

Finding the quantum thermoelectric with maximal efficiency and minimal entropy production at given power output

NASA Astrophysics Data System (ADS)

Whitney, Robert S.

2015-03-01

We investigate the nonlinear scattering theory for quantum systems with strong Seebeck and Peltier effects, and consider their use as heat engines and refrigerators with finite power outputs. This paper gives detailed derivations of the results summarized in a previous paper [R. S. Whitney, Phys. Rev. Lett. 112, 130601 (2014), 10.1103/PhysRevLett.112.130601]. It shows how to use the scattering theory to find (i) the quantum thermoelectric with maximum possible power output, and (ii) the quantum thermoelectric with maximum efficiency at given power output. The latter corresponds to a minimal entropy production at that power output. These quantities are of quantum origin since they depend on system size over electronic wavelength, and so have no analog in classical thermodynamics. The maximal efficiency coincides with Carnot efficiency at zero power output, but decreases with increasing power output. This gives a fundamental lower bound on entropy production, which means that reversibility (in the thermodynamic sense) is impossible for finite power output. The suppression of efficiency by (nonlinear) phonon and photon effects is addressed in detail; when these effects are strong, maximum efficiency coincides with maximum power. Finally, we show in particular limits (typically without magnetic fields) that relaxation within the quantum system does not allow the system to exceed the bounds derived for relaxation-free systems, however, a general proof of this remains elusive.

Ovulation Statuses of Surrogate Gilts Are Associated with the Efficiency of Excellent Pig Cloning.

PubMed

Huan, Yanjun; Hu, Kui; Xie, Bingteng; Shi, Yongqian; Wang, Feng; Zhou, Yang; Liu, Shichao; Huang, Bo; Zhu, Jiang; Liu, Zhongfeng; He, Yilong; Li, Jingyu; Kong, Qingran; Liu, Zhonghua

2015-01-01

Somatic cell nuclear transfer (SCNT) is an assisted reproductive technique that can produce multiple copies of excellent livestock. However, low cloning efficiency limits the application of SCNT. In this study, we systematically investigated the major influencing factors related to the overall cloning efficiency in pigs. Here, 13620 cloned embryos derived from excellent pigs were transferred into 79 surrogate gilts, and 119 live cloned piglets were eventually generated. During cloning, group of cloned embryos derived from excellent Landrace or Large white pigs presented no significant differences of cleavage and blastocyst rates, blastocyst cell numbers, surrogate pregnancy and delivery rates, average numbers of piglets born and alive and cloning efficiencies, and group of 101-150, 151-200 or 201-250 cloned embryos transferred per surrogate also displayed a similar developmental efficiency. When estrus stage of surrogate gilts was compared, group of embryo transfer on Day 2 of estrus showed significantly higher pregnancy rate, delivery rate, average number of piglets born, average alive piglet number or cloning efficiency than group on Day 1, Day 3, Day 4 or Day 5, respectively (P<0.05). And, in comparison with the preovulation and postovulation groups, group of surrogate gilts during periovulation displayed a significantly higher overall cloning efficiency (P<0.05). Further investigation of surrogate estrus stage and ovulation status displayed that ovulation status was the real factor underlying estrus stage to determine the overall cloning efficiency. And more, follicle puncture for preovulation, not transfer position shallowed for preovulation or deepened for postovulation, significantly improved the average number of piglets alive and cloning efficiency (P<0.05). In conclusion, our results demonstrated that ovulation status of surrogate gilts was the fundamental factor determining the overall cloning efficiency of excellent pigs, and follicle puncture, not transfer position change, improved cloning efficiency. This work would have important implications in preserving and breeding excellent livestock and improving the overall cloning efficiency.

Ovulation Statuses of Surrogate Gilts Are Associated with the Efficiency of Excellent Pig Cloning

PubMed Central

Huan, Yanjun; Hu, Kui; Xie, Bingteng; Shi, Yongqian; Wang, Feng; Zhou, Yang; Liu, Shichao; Huang, Bo; Zhu, Jiang; Liu, Zhongfeng; He, Yilong; Li, Jingyu; Kong, Qingran; Liu, Zhonghua

2015-01-01

Somatic cell nuclear transfer (SCNT) is an assisted reproductive technique that can produce multiple copies of excellent livestock. However, low cloning efficiency limits the application of SCNT. In this study, we systematically investigated the major influencing factors related to the overall cloning efficiency in pigs. Here, 13620 cloned embryos derived from excellent pigs were transferred into 79 surrogate gilts, and 119 live cloned piglets were eventually generated. During cloning, group of cloned embryos derived from excellent Landrace or Large white pigs presented no significant differences of cleavage and blastocyst rates, blastocyst cell numbers, surrogate pregnancy and delivery rates, average numbers of piglets born and alive and cloning efficiencies, and group of 101–150, 151–200 or 201–250 cloned embryos transferred per surrogate also displayed a similar developmental efficiency. When estrus stage of surrogate gilts was compared, group of embryo transfer on Day 2 of estrus showed significantly higher pregnancy rate, delivery rate, average number of piglets born, average alive piglet number or cloning efficiency than group on Day 1, Day 3, Day 4 or Day 5, respectively (P<0.05). And, in comparison with the preovulation and postovulation groups, group of surrogate gilts during periovulation displayed a significantly higher overall cloning efficiency (P<0.05). Further investigation of surrogate estrus stage and ovulation status displayed that ovulation status was the real factor underlying estrus stage to determine the overall cloning efficiency. And more, follicle puncture for preovulation, not transfer position shallowed for preovulation or deepened for postovulation, significantly improved the average number of piglets alive and cloning efficiency (P<0.05). In conclusion, our results demonstrated that ovulation status of surrogate gilts was the fundamental factor determining the overall cloning efficiency of excellent pigs, and follicle puncture, not transfer position change, improved cloning efficiency. This work would have important implications in preserving and breeding excellent livestock and improving the overall cloning efficiency. PMID:26565717

An improved 2D MoF method by using high order derivatives

NASA Astrophysics Data System (ADS)

Chen, Xiang; Zhang, Xiong

2017-11-01

The MoF (Moment of Fluid) method is one of the most accurate approaches among various interface reconstruction algorithms. Alike other second order methods, the MoF method needs to solve an implicit optimization problem to obtain the optimal approximate interface, so an iteration process is inevitable under most circumstances. In order to solve the optimization efficiently, the properties of the objective function are worthy of studying. In 2D problems, the first order derivative has been deduced and applied in the previous researches. In this paper, the high order derivatives of the objective function are deduced on the convex polygon. We show that the nth (n ≥ 2) order derivatives are discontinuous, and the number of the discontinuous points is two times the number of the polygon edge. A rotation algorithm is proposed to successively calculate these discontinuous points, thus the target interval where the optimal solution is located can be determined. Since the high order derivatives of the objective function are continuous in the target interval, the iteration schemes based on high order derivatives can be used to improve the convergence rate. Moreover, when iterating in the target interval, the value of objective function and its derivatives can be directly updated without explicitly solving the volume conservation equation. The direct update makes a further improvement of the efficiency especially when the number of edges of the polygon is increasing. The Halley's method, which is based on the first three order derivatives, is applied as the iteration scheme in this paper and the numerical results indicate that the CPU time is about half of the previous method on the quadrilateral cell and is about one sixth on the decagon cell.

a Novel Discrete Optimal Transport Method for Bayesian Inverse Problems

NASA Astrophysics Data System (ADS)

Bui-Thanh, T.; Myers, A.; Wang, K.; Thiery, A.

2017-12-01

We present the Augmented Ensemble Transform (AET) method for generating approximate samples from a high-dimensional posterior distribution as a solution to Bayesian inverse problems. Solving large-scale inverse problems is critical for some of the most relevant and impactful scientific endeavors of our time. Therefore, constructing novel methods for solving the Bayesian inverse problem in more computationally efficient ways can have a profound impact on the science community. This research derives the novel AET method for exploring a posterior by solving a sequence of linear programming problems, resulting in a series of transport maps which map prior samples to posterior samples, allowing for the computation of moments of the posterior. We show both theoretical and numerical results, indicating this method can offer superior computational efficiency when compared to other SMC methods. Most of this efficiency is derived from matrix scaling methods to solve the linear programming problem and derivative-free optimization for particle movement. We use this method to determine inter-well connectivity in a reservoir and the associated uncertainty related to certain parameters. The attached file shows the difference between the true parameter and the AET parameter in an example 3D reservoir problem. The error is within the Morozov discrepancy allowance with lower computational cost than other particle methods.

Establishment of a Charge Reversal Derivatization Strategy to Improve the Ionization Efficiency of Limaprost and Investigation of the Fragmentation Patterns of Limaprost Derivatives Via Exclusive Neutral Loss and Survival Yield Method

NASA Astrophysics Data System (ADS)

Sun, Dong; Meng, Xiangjun; Ren, Tianming; Fawcett, John Paul; Wang, Hualu; Gu, Jingkai

2018-04-01

Sensitivity is generally an issue in bioassays of prostaglandins and their synthetic analogs due to their extremely low concentration in vivo. To improve the ionization efficiency of limaprost, an oral prostaglandin E1 (PGE1) synthetic analog, we investigated a charge reversal derivatization strategy in electrospray ionization mass spectrometry (ESI-MS). We established that the cholamine derivative exhibits much greater signal intensity in the positive-ion mode compared with limaprost in the negative ion mode. Collision-induced dissociation (CID) involved exclusive neutral mass loss and positive charge migration to form stable cationic product ions with the positive charge on the limaprost residue rather than on the modifying group. This has the effect of maintaining the efficiency and specificity of multiple reaction monitoring (MRM) and avoiding cross talk. CID fragmentation patterns of other limaprost derivatives allowed us to relate the dissociation tendency of different neutral leaving groups to an internal energy distribution scale based on the survival yield method. Knowledge of the energy involved in the production of stabilized positive ions will potentially assist the selection of suitable derivatization reagents for the analysis of a wide variety of lipid acids. [Figure not available: see fulltext.

An optimal control strategy for hybrid actuator systems: Application to an artificial muscle with electric motor assist.

PubMed

Ishihara, Koji; Morimoto, Jun

2018-03-01

Humans use multiple muscles to generate such joint movements as an elbow motion. With multiple lightweight and compliant actuators, joint movements can also be efficiently generated. Similarly, robots can use multiple actuators to efficiently generate a one degree of freedom movement. For this movement, the desired joint torque must be properly distributed to each actuator. One approach to cope with this torque distribution problem is an optimal control method. However, solving the optimal control problem at each control time step has not been deemed a practical approach due to its large computational burden. In this paper, we propose a computationally efficient method to derive an optimal control strategy for a hybrid actuation system composed of multiple actuators, where each actuator has different dynamical properties. We investigated a singularly perturbed system of the hybrid actuator model that subdivided the original large-scale control problem into smaller subproblems so that the optimal control outputs for each actuator can be derived at each control time step and applied our proposed method to our pneumatic-electric hybrid actuator system. Our method derived a torque distribution strategy for the hybrid actuator by dealing with the difficulty of solving real-time optimal control problems. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Sampling for Patient Exit Interviews: Assessment of Methods Using Mathematical Derivation and Computer Simulations.

PubMed

Geldsetzer, Pascal; Fink, Günther; Vaikath, Maria; Bärnighausen, Till

2018-02-01

(1) To evaluate the operational efficiency of various sampling methods for patient exit interviews; (2) to discuss under what circumstances each method yields an unbiased sample; and (3) to propose a new, operationally efficient, and unbiased sampling method. Literature review, mathematical derivation, and Monte Carlo simulations. Our simulations show that in patient exit interviews it is most operationally efficient if the interviewer, after completing an interview, selects the next patient exiting the clinical consultation. We demonstrate mathematically that this method yields a biased sample: patients who spend a longer time with the clinician are overrepresented. This bias can be removed by selecting the next patient who enters, rather than exits, the consultation room. We show that this sampling method is operationally more efficient than alternative methods (systematic and simple random sampling) in most primary health care settings. Under the assumption that the order in which patients enter the consultation room is unrelated to the length of time spent with the clinician and the interviewer, selecting the next patient entering the consultation room tends to be the operationally most efficient unbiased sampling method for patient exit interviews. © 2016 The Authors. Health Services Research published by Wiley Periodicals, Inc. on behalf of Health Research and Educational Trust.

Methods comparison for microsatellite marker development: Different isolation methods, different yield efficiency

NASA Astrophysics Data System (ADS)

Zhan, Aibin; Bao, Zhenmin; Hu, Xiaoli; Lu, Wei; Hu, Jingjie

2009-06-01

Microsatellite markers have become one kind of the most important molecular tools used in various researches. A large number of microsatellite markers are required for the whole genome survey in the fields of molecular ecology, quantitative genetics and genomics. Therefore, it is extremely necessary to select several versatile, low-cost, efficient and time- and labor-saving methods to develop a large panel of microsatellite markers. In this study, we used Zhikong scallop ( Chlamys farreri) as the target species to compare the efficiency of the five methods derived from three strategies for microsatellite marker development. The results showed that the strategy of constructing small insert genomic DNA library resulted in poor efficiency, while the microsatellite-enriched strategy highly improved the isolation efficiency. Although the mining public database strategy is time- and cost-saving, it is difficult to obtain a large number of microsatellite markers, mainly due to the limited sequence data of non-model species deposited in public databases. Based on the results in this study, we recommend two methods, microsatellite-enriched library construction method and FIASCO-colony hybridization method, for large-scale microsatellite marker development. Both methods were derived from the microsatellite-enriched strategy. The experimental results obtained from Zhikong scallop also provide the reference for microsatellite marker development in other species with large genomes.

Retrieval of spheroid particle size distribution from spectral extinction data in the independent mode using PCA approach

NASA Astrophysics Data System (ADS)

Tang, Hong; Lin, Jian-Zhong

2013-01-01

An improved anomalous diffraction approximation (ADA) method is presented for calculating the extinction efficiency of spheroids firstly. In this approach, the extinction efficiency of spheroid particles can be calculated with good accuracy and high efficiency in a wider size range by combining the Latimer method and the ADA theory, and this method can present a more general expression for calculating the extinction efficiency of spheroid particles with various complex refractive indices and aspect ratios. Meanwhile, the visible spectral extinction with varied spheroid particle size distributions and complex refractive indices is surveyed. Furthermore, a selection principle about the spectral extinction data is developed based on PCA (principle component analysis) of first derivative spectral extinction. By calculating the contribution rate of first derivative spectral extinction, the spectral extinction with more significant features can be selected as the input data, and those with less features is removed from the inversion data. In addition, we propose an improved Tikhonov iteration method to retrieve the spheroid particle size distributions in the independent mode. Simulation experiments indicate that the spheroid particle size distributions obtained with the proposed method coincide fairly well with the given distributions, and this inversion method provides a simple, reliable and efficient method to retrieve the spheroid particle size distributions from the spectral extinction data.

EOSCUBE: A Constraint Database System for High-Level Specification and Efficient Generation of EOSDIS Products. Phase 1; Proof-of-Concept

NASA Technical Reports Server (NTRS)

Brodsky, Alexander; Segal, Victor E.

1999-01-01

The EOSCUBE constraint database system is designed to be a software productivity tool for high-level specification and efficient generation of EOSDIS and other scientific products. These products are typically derived from large volumes of multidimensional data which are collected via a range of scientific instruments.

Resource values in analyzing fire management programs for economic efficiency

Treesearch

Irene A. Althaus; Thomas J. Mills

1982-01-01

In analyzing fire management programs for their economic efficiency, it is necessary to assign monetary values to the changes in resource outputs caused by, fire. The derivation of resource values is complicated by imperfect or nonexistent commercial market structures. The valuation concept recommended for fire program analyses is willingness-to-pay because it permits...

Efficiency Versus Instability in Plasma Accelerators

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

Lebedev, Valeri; Burov, Alexey; Nagaitsev, Sergei

2017-01-05

Plasma wake-field acceleration in a strongly nonlinear (a.k.a. the blowout) regime is one of the main candidates for future high-energy colliders. For this case, we derive a universal efficiency-instability relation, between the power efficiency and the key instability parameter of the witness bunch. We also show that in order to stabilize the witness bunch in a regime with high power efficiency, the bunch needs to have high energy spread, which is not presently compatible with collider-quality beam properties. It is unclear how such limitations could be overcome for high-luminosity linear colliders.

Efficient control schemes with limited computation complexity for Tomographic AO systems on VLTs and ELTs

NASA Astrophysics Data System (ADS)

Petit, C.; Le Louarn, M.; Fusco, T.; Madec, P.-Y.

2011-09-01

Various tomographic control solutions have been proposed during the last decades to ensure efficient or even optimal closed-loop correction to tomographic Adaptive Optics (AO) concepts such as Laser Tomographic AO (LTAO), Multi-Conjugate AO (MCAO). The optimal solution, based on Linear Quadratic Gaussian (LQG) approach, as well as suboptimal but efficient solutions such as Pseudo-Open Loop Control (POLC) require multiple Matrix Vector Multiplications (MVM). Disregarding their respective performance, these efficient control solutions thus exhibit strong increase of on-line complexity and their implementation may become difficult in demanding cases. Among them, two cases are of particular interest. First, the system Real-Time Computer architecture and implementation is derived from past or present solutions and does not support multiple MVM. This is the case of the AO Facility which RTC architecture is derived from the SPARTA platform and inherits its simple MVM architecture, which does not fit with LTAO control solutions for instance. Second, considering future systems such as Extremely Large Telescopes, the number of degrees of freedom is twenty to one hundred times bigger than present systems. In these conditions, tomographic control solutions can hardly be used in their standard form and optimized implementation shall be considered. Single MVM tomographic control solutions represent a potential solution, and straightforward solutions such as Virtual Deformable Mirrors have been already proposed for LTAO but with tuning issues. We investigate in this paper the possibility to derive from tomographic control solutions, such as POLC or LQG, simplified control solutions ensuring simple MVM architecture and that could be thus implemented on nowadays systems or future complex systems. We theoretically derive various solutions and analyze their respective performance on various systems thanks to numerical simulation. We discuss the optimization of their performance and stability issues with respect to classic control solutions. We finally discuss off-line computation and implementation constraints.

Degradable polyethylenimine derivate coupled to a bifunctional peptide R13 as a new gene-delivery vector

PubMed Central

Liu, Kehai; Wang, Xiaoyu; Fan, Wei; Zhu, Qing; Yang, Jingya; Gao, Jing; Gao, Shen

2012-01-01

Background To solve the efficiency versus cytotoxicity and tumor-targeting problems of polyethylenimine (PEI) used as a nonviral gene delivery vector, a degradable PEI derivate coupled to a bifunctional peptide R13 was developed. Methods First, we synthesized a degradable PEI derivate by crosslinking low-molecular-weight PEI with pluronic P123, then used tumor-targeting peptide arginine-glycine-aspartate-cysteine (RGDC), in conjunction with the cell-penetrating peptide Tat (49–57), to yield a bifunctional peptide RGDC-Tat (49–57) named R13, which can improve cell selection and increase cellular uptake, and, lastly, adopted R13 to modify the PEI derivates so as to prepare a new polymeric gene vector (P123-PEI-R13). The new gene vector was characterized in terms of its chemical structure and biophysical parameters. We also investigated the specificity, cytotoxicity, and gene transfection efficiency of this vector in αvβ3-positive human cervical carcinoma Hela cells and murine melanoma B16 cells in vitro. Results The vector showed controlled degradation, strong targeting specificity to αvβ3 receptor, and noncytotoxicity in Hela cells and B16 cells at higher doses, in contrast to PEI 25 KDa. The particle size of P123-PEI-R13/DNA complexes was around 100–250 nm, with proper zeta potential. The nanoparticles can protect plasmid DNA from being digested by DNase I at a concentration of 6 U DNase I/μg DNA. The nanoparticles were resistant to dissociation induced by 50% fetal bovine serum and 600 μg/mL sodium heparin. P123-PEI-R13 also revealed higher transfection efficiency in two cell lines as compared with PEI 25 KDa. Conclusion P123-PEI-R13 is a potential candidate as a safe and efficient gene-delivery carrier for gene therapy. PMID:22412301

Technology for aircraft energy efficiency

NASA Technical Reports Server (NTRS)

Klineberg, J. M.

1977-01-01

Six technology programs for reducing fuel use in U.S. commercial aviation are discussed. The six NASA programs are divided into three groups: Propulsion - engine component improvement, energy efficient engine, advanced turboprops; Aerodynamics - energy efficient transport, laminar flow control; and Structures - composite primary structures. Schedules, phases, and applications of these programs are considered, and it is suggested that program results will be applied to current transport derivatives in the early 1980s and to all-new aircraft of the late 1980s and early 1990s.

Infrared measurements of a scramjet exhaust. [to determine combustion efficiency

NASA Technical Reports Server (NTRS)

Reed, R. A.; Slack, M. W.

1980-01-01

Diagnostic 2 - 5 mm infrared spectra of a hydrogen burning scramjet exhaust were measured with an interferometer spectrometer. Exhaust gas temperatures and water vapor partial pressures were determined from the observed intensity and spectral profile of the H2O 2.7 mm infrared emission band. Overall engine combustion efficiencies were derived by combining these measurements with the known engine operating conditions. Efficiencies fall (70 - 50 percent) as fuel equivalence ratios rise (0.4 - 1.0). Data analysis techniques and sensitivity studies are also presented.

Assessing overall, technical, and scale efficiency among home health care agencies.

PubMed

Valdmanis, Vivian G; Rosko, Michael D; Leleu, Hervé; Mukamel, Dana B

2017-06-01

While home health care agencies (HHAs) play a vital role in the production of health, little research has been performed gauging their efficiency. Employing a robust approach to data envelopment analysis (DEA) we assessed overall, technical, and scale efficiency on a nationwide sample of HHAs. After deriving the three efficiency measures, we regressed these scores on a variety of environmental factors. We found that HHAs, on average, could proportionally reduce inputs by 28 % (overall efficiency), 23 % (technical efficiency) and 6 % (scale efficiency). For-profit ownership was positively associated with improvements in overall efficiency and technical efficiency and chain ownership was positively associated with global efficiency. There were also state-by-state variations on all the efficiency measures. As home health becomes an increasingly important player in the health care system, and its share of national health expenditures increases, it has become important to understand the cost structure of the industry and the potential for efficiencies. Therefore, further research is recommended as this sector continues to grow.

MUNICIPAL WASTE COMBUSTION MULTIPOLLUTANT STUDY EMISSION TEST REPORT, MAINE ENERGY RECOVERY COMPANY, REFUSE DERIVED FUEL FACILITY, BIDDEFORD, MAINE - VOLUME III: APPENDICES G-N

EPA Science Inventory

The report gives results of an emission test of a new municipal solid waste combustor, in Biddeford, ME, that burns refuse-derived fuel and is equipped with a lime spray dryer fabric filter (SD/FF) emission control system. Control efficiency of the SD/FF emission control system ...

MUNICIPAL WASTE COMBUSTION MULTIPOLLUTANT STUDY EMISSION TEST REPORT, MAINE ENERGY RECOVERY COMPANY, REFUSE DERIVED FUEL FACILITY, BIDDEFORD, MAINE - VOLUME II: APPENDICES A-F

EPA Science Inventory

The report gives results of an emission test of a new municipal solid waste combustor, in Biddeford, ME, that burns refuse-derived fuel and is equipped with a lime spray dryer fabric filter (SD/FF) emission control system. Control efficiency of the SD/FF emission control system ...

Effects of Reabsorption and Spatial Trap Distributions on the Radiative Quantum Efficiencies of ZnO

DTIC Science & Technology

2010-06-06

in (a)] due to reabsorption, and the probability f reflesc of photon escape due to Fresnel reflection [derived from Eq. (1) and a Kramers- Kronig ...according to Eq. (1) using an index of refraction n(h̄ω) derived from a Kramers- Kronig transformation of the estimated absorption spectrum in Fig. 3(a

Tumor cell-derived microparticles: a new form of cancer vaccine.

PubMed

Zhang, Huafeng; Huang, Bo

2015-08-01

For cancer vaccines, tumor antigen availability is currently not an issue due to technical advances. However, the generation of optimal immune stimulation during vaccination is challenging. We have recently demonstrated that tumor cell-derived microparticles (MP) can function as a new form of potent cancer vaccine by efficiently activating type I interferon pathway in a cGAS/STING dependent manner.

An efficient mode-splitting method for a curvilinear nearshore circulation model

USGS Publications Warehouse

Shi, Fengyan; Kirby, James T.; Hanes, Daniel M.

2007-01-01

A mode-splitting method is applied to the quasi-3D nearshore circulation equations in generalized curvilinear coordinates. The gravity wave mode and the vorticity wave mode of the equations are derived using the two-step projection method. Using an implicit algorithm for the gravity mode and an explicit algorithm for the vorticity mode, we combine the two modes to derive a mixed difference–differential equation with respect to surface elevation. McKee et al.'s [McKee, S., Wall, D.P., and Wilson, S.K., 1996. An alternating direction implicit scheme for parabolic equations with mixed derivative and convective terms. J. Comput. Phys., 126, 64–76.] ADI scheme is then used to solve the parabolic-type equation in dealing with the mixed derivative and convective terms from the curvilinear coordinate transformation. Good convergence rates are found in two typical cases which represent respectively the motions dominated by the gravity mode and the vorticity mode. Time step limitations imposed by the vorticity convective Courant number in vorticity-mode-dominant cases are discussed. Model efficiency and accuracy are verified in model application to tidal current simulations in San Francisco Bight.

Pd/activated carbon sorbents for mid-temperature capture of mercury from coal-derived fuel gas.

PubMed

Li, Dekui; Han, Jieru; Han, Lina; Wang, Jiancheng; Chang, Liping

2014-07-01

Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great importance. Based on the very excellent Hg removal ability of Pd and the high adsorption abilities of activated carbon (AC) for H₂S and Hg, a series of Pd/AC sorbents was prepared by using pore volume impregnation, and their performance in capturing Hg and H₂S from coal-derived fuel gas was investigated using a laboratory-scale fixed-bed reactor. The effects of loading amount, reaction temperature and reaction atmosphere on Hg removal from coal-derived fuel gas were studied. The sorbents were characterized by N₂ adsorption, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicated that the efficiency of Hg removal increased with the increasing of Pd loading amount, but the effective utilization rate of the active component Pd decreased significantly at the same time. High temperature had a negative influence on the Hg removal. The efficiency of Hg removal in the N₂-H₂S-H₂-CO-Hg atmosphere (simulated coal gas) was higher than that in N₂-H₂S-Hg and N₂-Hg atmospheres, which showed that H₂ and CO, with their reducing capacity, could benefit promote the removal of Hg. The XPS results suggested that there were two different ways of capturing Hg over sorbents in N₂-H₂S-Hg and N₂-Hg atmospheres. Copyright © 2014. Published by Elsevier B.V.

A small and efficient dimerization/packaging signal of rat VL30 RNA and its use in murine leukemia virus-VL30-derived vectors for gene transfer.

PubMed Central

Torrent, C; Gabus, C; Darlix, J L

1994-01-01

Retroviral genomes consist of two identical RNA molecules associated at their 5' ends by the dimer linkage structure located in the packaging element (Psi or E) necessary for RNA dimerization in vitro and packaging in vivo. In murine leukemia virus (MLV)-derived vectors designed for gene transfer, the Psi + sequence of 600 nucleotides directs the packaging of recombinant RNAs into MLV virions produced by helper cells. By using in vitro RNA dimerization as a screening system, a sequence of rat VL30 RNA located next to the 5' end of the Harvey mouse sarcoma virus genome and as small as 67 nucleotides was found to form stable dimeric RNA. In addition, a purine-rich sequence located at the 5' end of this VL30 RNA seems to be critical for RNA dimerization. When this VL30 element was extended by 107 nucleotides at its 3' end and inserted into an MLV-derived vector lacking MLV Psi +, it directed the efficient encapsidation of recombinant RNAs into MLV virions. Because this VL30 packaging signal is smaller and more efficient in packaging recombinant RNAs than the MLV Psi + and does not contain gag or glyco-gag coding sequences, its use in MLV-derived vectors should render even more unlikely recombinations which could generate replication-competent viruses. Therefore, utilization of the rat VL30 packaging sequence should improve the biological safety of MLV vectors for human gene transfer. Images PMID:8289369

Fast gravity, gravity partials, normalized gravity, gravity gradient torque and magnetic field: Derivation, code and data

NASA Technical Reports Server (NTRS)

Gottlieb, Robert G.

1993-01-01

Derivation of first and second partials of the gravitational potential is given in both normalized and unnormalized form. Two different recursion formulas are considered. Derivation of a general gravity gradient torque algorithm which uses the second partial of the gravitational potential is given. Derivation of the geomagnetic field vector is given in a form that closely mimics the gravitational algorithm. Ada code for all algorithms that precomputes all possible data is given. Test cases comparing the new algorithms with previous data are given, as well as speed comparisons showing the relative efficiencies of the new algorithms.

Isolation of Human Induced Pluripotent Stem Cell-Derived Dopaminergic Progenitors by Cell Sorting for Successful Transplantation

PubMed Central

Doi, Daisuke; Samata, Bumpei; Katsukawa, Mitsuko; Kikuchi, Tetsuhiro; Morizane, Asuka; Ono, Yuichi; Sekiguchi, Kiyotoshi; Nakagawa, Masato; Parmar, Malin; Takahashi, Jun

2014-01-01

Summary Human induced pluripotent stem cells (iPSCs) can provide a promising source of midbrain dopaminergic (DA) neurons for cell replacement therapy for Parkinson’s disease. However, iPSC-derived donor cells inevitably contain tumorigenic or inappropriate cells. Here, we show that human iPSC-derived DA progenitor cells can be efficiently isolated by cell sorting using a floor plate marker, CORIN. We induced DA neurons using scalable culture conditions on human laminin fragment, and the sorted CORIN+ cells expressed the midbrain DA progenitor markers, FOXA2 and LMX1A. When transplanted into 6-OHDA-lesioned rats, the CORIN+ cells survived and differentiated into midbrain DA neurons in vivo, resulting in significant improvement of the motor behavior, without tumor formation. In particular, the CORIN+ cells in a NURR1+ cell-dominant stage exhibited the best survival and function as DA neurons. Our method is a favorable strategy in terms of scalability, safety, and efficiency and may be advantageous for clinical application. PMID:24672756

Synthesis of vertical MnO2 wire arrays on hemp-derived carbon for efficient and robust green catalysts

NASA Astrophysics Data System (ADS)

Yang, MinHo; Kim, Dong Seok; Sim, Jae-Wook; Jeong, Jae-Min; Kim, Do Hyun; Choi, Jae Hyung; Kim, Jinsoo; Kim, Seung-Soo; Choi, Bong Gill

2017-06-01

Three-dimensional (3D) carbon materials derived from waste biomass have been attracted increasing attention in catalysis and materials science because of their great potential of catalyst supports with respect to multi-functionality, unique structures, high surface area, and low cost. Here, we present a facile and efficient way for preparing 3D heterogeneous catalysts based on vertical MnO2 wires deposited on hemp-derived 3D porous carbon. The 3D porous carbon materials are fabricated by carbonization and activation processes using hemp (Cannabis Sttiva L.). These 3D porous carbon materials are employed as catalyst supports for direct deposition of vertical MnO2 wires using a one-step hydrothermal method. The XRD and XPS results reveal the crystalline structure of α-MnO2 wires. The resultant composites are further employed as a catalyst for glycolysis of poly(ethylene terephthalate) (PET) with high conversion yield of 98%, which is expected to be expressly profitable for plastics recycling industry.

A simple method for the enrichment of bisphenols using boron nitride.

PubMed

Fischnaller, Martin; Bakry, Rania; Bonn, Günther K

2016-03-01

A simple solid-phase extraction method for the enrichment of 5 bisphenol derivatives using hexagonal boron nitride (BN) was developed. BN was applied to concentrate bisphenol derivatives in spiked water samples and the compounds were analyzed using HPLC coupled to fluorescence detection. The effect of pH and organic solvents on the extraction efficiency was investigated. An enrichment factor up to 100 was achieved without evaporation and reconstitution. The developed method was applied for the determination of bisphenol A migrated from some polycarbonate plastic products. Furthermore, bisphenol derivatives were analyzed in spiked and non-spiked canned food and beverages. None of the analyzed samples exceeded the migration limit set by the European Union of 0.6mg/kg food. The method showed good recovery rates ranging from 80% to 110%. Validation of the method was performed in terms of accuracy and precision. The applied method is robust, fast, efficient and easily adaptable to different analytical problems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficiently computing and deriving topological relation matrices between complex regions with broad boundaries

NASA Astrophysics Data System (ADS)

Du, Shihong; Guo, Luo; Wang, Qiao; Qin, Qimin

The extended 9-intersection matrix is used to formalize topological relations between uncertain regions while it is designed to satisfy the requirements at a concept level, and to deal with the complex regions with broad boundaries (CBBRs) as a whole without considering their hierarchical structures. In contrast to simple regions with broad boundaries, CBBRs have complex hierarchical structures. Therefore, it is necessary to take into account the complex hierarchical structure and to represent the topological relations between all regions in CBBRs as a relation matrix, rather than using the extended 9-intersection matrix to determine topological relations. In this study, a tree model is first used to represent the intrinsic configuration of CBBRs hierarchically. Then, the reasoning tables are presented for deriving topological relations between child, parent and sibling regions from the relations between two given regions in CBBRs. Finally, based on the reasoning, efficient methods are proposed to compute and derive the topological relation matrix. The proposed methods can be incorporated into spatial databases to facilitate geometric-oriented applications.

Statistical thermodynamics foundation for photovoltaic and photothermal conversion. II. Application to photovoltaic conversion

NASA Astrophysics Data System (ADS)

Badescu, Viorel; Landsberg, Peter T.

1995-08-01

The general theory developed in part I was applied to build up two models of photovoltaic conversion. To this end two different systems were analyzed. The first system consists of the whole absorber (converter), for which the balance equations for energy and entropy are written and then used to derive an upper bound for solar energy conversion. The second system covers a part of the absorber (converter), namely the valence and conduction electronic bands. The balance of energy is used in this case to derive, under additional assumptions, another upper limit for the conversion efficiency. This second system deals with the real location where the power is generated. Both models take into consideration the radiation polarization and reflection, and the effects of concentration. The second model yields a more accurate upper bound for the conversion efficiency. A generalized solar cell equation is derived. It is proved that other previous theories are particular cases of the present more general formalism.

Proportional-integral and proportional-integral-derivative-based cyclic sleep controllers with anti-windup technique for energy-efficient and delay-aware passive optical networks

NASA Astrophysics Data System (ADS)

Kikuchi, Takahiro; Kubo, Ryogo

2016-08-01

In energy-efficient passive optical network (PON) systems, the increase in the queuing delays caused by the power-saving mechanism of optical network units (ONUs) is an important issue. Some researchers have proposed quality-of-service (QoS)-aware ONU cyclic sleep controllers in PON systems. We have proposed proportional (P) and proportional-derivative (PD)-based controllers to maintain the average queuing delay at a constant level regardless of the amount of downstream traffic. However, sufficient performance has not been obtained because of the sleep period limitation. In this paper, proportional-integral (PI) and proportional-integral-derivative (PID)-based controllers considering the sleep period limitation, i.e., using an anti-windup (AW) technique, are proposed to improve both the QoS and power-saving performance. Simulations confirm that the proposed controllers provide better performance than conventional controllers in terms of the average downstream queuing delay and the time occupancy of ONU active periods.

Turbine Inlet Air Cooling for Industrial and Aero-derivative Gas Turbine in Malaysia Climate

NASA Astrophysics Data System (ADS)

Nordin, A.; Salim, D. A.; Othoman, M. A.; Kamal, S. N. Omar; Tam, Danny; Yusof, M. KY

2017-12-01

The performance of a gas turbine is dependent on the ambient temperature. A higher temperature results in a reduction of the gas turbine’s power output and an increase in heat rate. The warm and humid climate in Malaysia with its high ambient air temperature has an adverse effect on the performance of gas turbine generators. In this paper, the expected effect of turbine inlet air cooling technology on the annual performance of an aero-derivative gas turbine (GE LM6000PD) is compared against that of an industrial gas turbine (GEFr6B.03) using GT Pro software. This study investigated the annual net energy output and the annual net electrical efficiency of a plant with and without turbine inlet air cooling technology. The results show that the aero-derivative gas turbine responds more favorably to turbine inlet air cooling technology, thereby yielding higher annual net energy output and higher net electrical efficiency when compared to the industrial gas turbine.

Enhanced cellulase producing mutants developed from heterokaryotic Aspergillus strain.

PubMed

Kaur, Baljit; Oberoi, H S; Chadha, B S

2014-03-01

A heterokaryon 28, derived through protoplast fusion between Aspergillus nidulans and Aspergillus tubingensis (Dal8), was subjected cyclic mutagenesis followed by selection on increasing levels of 2-deoxy glucose (2-DG) as selection marker. The derived deregulated cellulase hyper producing mutant '64', when compared to fusant 28, produced 9.83, 7.8, 3.2, 4.2 and 19.74 folds higher endoglucanase, β-glucosidase, cellobiohydrolase, FPase and xylanase, respectively, under shake cultures. The sequence analysis of PCR amplified β-glucosidase gene from wild and mutant showed nucleotide deletion/substitution. The mutants showed highly catalytic efficient β-glucosidase as evident from low Km and high Vmax values. The expression profiling through zymogram analysis also indicated towards over-expression of cellulases. The up/down regulated expressed proteins observed through SDS-PAGE were identified by Peptide mass fingerprinting The cellulase produced by mutants in conjunction with cellulase free xylanase derived from Thermomyces lanuginosus was used for efficient utilization of alkali treated rice straw for obtaining xylo-oligosaccharides and ethanol. Copyright © 2014 Elsevier Ltd. All rights reserved.

Energy Savings Lifetimes and Persistence

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

Hoffman, Ian M.; Schiller, Steven R.; Todd, Annika

2016-02-01

This technical brief explains the concepts of energy savings lifetimes and savings persistence and discusses how program administrators use these factors to calculate savings for efficiency measures, programs and portfolios. Savings lifetime is the length of time that one or more energy efficiency measures or activities save energy, and savings persistence is the change in savings throughout the functional life of a given efficiency measure or activity. Savings lifetimes are essential for assessing the lifecycle benefits and cost effectiveness of efficiency activities and for forecasting loads in resource planning. The brief also provides estimates of savings lifetimes derived from amore » national collection of costs and savings for electric efficiency programs and portfolios.« less

Cryopreservation of Human Adipose-Derived Stem Cells in Combination with Trehalose and Reversible Electroporation.

PubMed

Dovgan, Barbara; Barlič, Ariana; Knežević, Miomir; Miklavčič, Damijan

2017-02-01

New cryopreservation approaches for medically applicable cells are of great importance in clinical medicine. Current protocols employ the use of dimethyl sulfoxide (DMSO), which is toxic to cells and causes undesirable side effects in patients, such as cardiac arrhythmias, neurological events, and others. Trehalose, a nontoxic disaccharide, has been already studied as a cryoprotectant. However, an efficient approach for loading this impermeable sugar into mammalian cells is missing. In our study, we assessed the efficiency of combining reversible electroporation and trehalose for cryopreservation of human adipose-derived stem cells. First, we determined reversible electroporation threshold by loading of propidium iodide into cells. The highest permeabilization while maintaining high cell viability was reached at 1.5 kV/cm, at 8 pulses, 100 µs, and 1 Hz. Second, cells were incubated in 250 or 400 mM trehalose and electroporated before cryopreservation. After thawing, 83.8 ± 1.8 % (mean ± SE) cell recovery was obtained at 250 mM trehalose. By using a standard freezing protocol (10 % DMSO in 90 % fetal bovine serum), cell survival after thawing was about 91.5 ± 1.6 %. We also evaluated possible effects of electroporation on cells' functionality before and after thawing. Successful cell growth and efficient adipogenic and osteogenic differentiation were achieved. In conclusion, electroporation seems to be an efficient method for loading nonpermeable trehalose into human adipose-derived stem cells, allowing long-term cryopreservation in DMSO-free and xeno-free conditions.

Synthesis of ketones from biomass-derived feedstock.

PubMed

Meng, Qinglei; Hou, Minqiang; Liu, Huizhen; Song, Jinliang; Han, Buxing

2017-01-31

Cyclohexanone and its derivatives are very important chemicals, which are currently produced mainly by oxidation of cyclohexane or alkylcyclohexane, hydrogenation of phenols, and alkylation of cyclohexanone. Here we report that bromide salt-modified Pd/C in H 2 O/CH 2 Cl 2 can efficiently catalyse the transformation of aromatic ethers, which can be derived from biomass, to cyclohexanone and its derivatives via hydrogenation and hydrolysis processes. The yield of cyclohexanone from anisole can reach 96%, and the yields of cyclohexanone derivatives produced from the aromatic ethers, which can be extracted from plants or derived from lignin, are also satisfactory. Detailed study shows that the Pd, bromide salt and H 2 O/CH 2 Cl 2 work cooperatively to promote the desired reaction and inhibit the side reaction. Thus high yields of desired products can be obtained. This work opens the way for production of ketones from aromatic ethers that can be derived from biomass.

Probing the Active Surface Sites for CO Reduction on Oxide-Derived Copper Electrocatalysts

DOE PAGES

Verdaguer-Casadevall, Arnau; Li, Christina W.; Johansson, Tobias P.; ...

2015-07-30

CO electroreduction activity on oxide-derived Cu (OD-Cu) was found to correlate with metastable surface features that bind CO strongly. OD-Cu electrodes prepared by H 2 reduction of Cu 2O precursors reduce CO to acetate and ethanol with nearly 50% Faradaic efficiency at moderate overpotential. Temperature-programmed desorption of CO on OD-Cu revealed the presence of surface sites with strong CO binding that are distinct from the terraces and stepped sites found on polycrystalline Cu foil. After annealing at 350 °C, the surface-area corrected current density for CO reduction is 44-fold lower and the Faradaic efficiency is less than 5%. These changesmore » are accompanied by a reduction in the proportion of strong CO binding sites. Here, we propose that the active sites for CO reduction on OD-Cu surfaces are strong CO binding sites that are supported by grain boundaries. Uncovering these sites is a first step toward understanding the surface chemistry necessary for efficient CO electroreduction.« less

Spatio-Temporal Convergence of Maximum Daily Light-Use Efficiency Based on Radiation Absorption by Canopy Chlorophyll

NASA Astrophysics Data System (ADS)

Zhang, Yao; Xiao, Xiangming; Wolf, Sebastian; Wu, Jin; Wu, Xiaocui; Gioli, Beniamino; Wohlfahrt, Georg; Cescatti, Alessandro; van der Tol, Christiaan; Zhou, Sha; Gough, Christopher M.; Gentine, Pierre; Zhang, Yongguang; Steinbrecher, Rainer; Ardö, Jonas

2018-04-01

Light-use efficiency (LUE), which quantifies the plants' efficiency in utilizing solar radiation for photosynthetic carbon fixation, is an important factor for gross primary production estimation. Here we use satellite-based solar-induced chlorophyll fluorescence as a proxy for photosynthetically active radiation absorbed by chlorophyll (APARchl) and derive an estimation of the fraction of APARchl (fPARchl) from four remotely sensed vegetation indicators. By comparing maximum LUE estimated at different scales from 127 eddy flux sites, we found that the maximum daily LUE based on PAR absorption by canopy chlorophyll (ɛmaxchl), unlike other expressions of LUE, tends to converge across biome types. The photosynthetic seasonality in tropical forests can also be tracked by the change of fPARchl, suggesting the corresponding ɛmaxchl to have less seasonal variation. This spatio-temporal convergence of LUE derived from fPARchl can be used to build simple but robust gross primary production models and to better constrain process-based models.

Light-efficient photography.

PubMed

Hasinoff, Samuel W; Kutulakos, Kiriakos N

2011-11-01

In this paper, we consider the problem of imaging a scene with a given depth of field at a given exposure level in the shortest amount of time possible. We show that by 1) collecting a sequence of photos and 2) controlling the aperture, focus, and exposure time of each photo individually, we can span the given depth of field in less total time than it takes to expose a single narrower-aperture photo. Using this as a starting point, we obtain two key results. First, for lenses with continuously variable apertures, we derive a closed-form solution for the globally optimal capture sequence, i.e., that collects light from the specified depth of field in the most efficient way possible. Second, for lenses with discrete apertures, we derive an integer programming problem whose solution is the optimal sequence. Our results are applicable to off-the-shelf cameras and typical photography conditions, and advocate the use of dense, wide-aperture photo sequences as a light-efficient alternative to single-shot, narrow-aperture photography.

Efficient Convex Optimization for Energy-Based Acoustic Sensor Self-Localization and Source Localization in Sensor Networks.

PubMed

Yan, Yongsheng; Wang, Haiyan; Shen, Xiaohong; Leng, Bing; Li, Shuangquan

2018-05-21

The energy reading has been an efficient and attractive measure for collaborative acoustic source localization in practical application due to its cost saving in both energy and computation capability. The maximum likelihood problems by fusing received acoustic energy readings transmitted from local sensors are derived. Aiming to efficiently solve the nonconvex objective of the optimization problem, we present an approximate estimator of the original problem. Then, a direct norm relaxation and semidefinite relaxation, respectively, are utilized to derive the second-order cone programming, semidefinite programming or mixture of them for both cases of sensor self-location and source localization. Furthermore, by taking the colored energy reading noise into account, several minimax optimization problems are formulated, which are also relaxed via the direct norm relaxation and semidefinite relaxation respectively into convex optimization problems. Performance comparison with the existing acoustic energy-based source localization methods is given, where the results show the validity of our proposed methods.

Efficient transduction of equine adipose-derived mesenchymal stem cells by VSV-G pseudotyped lentiviral vectors.

PubMed

Petersen, Gayle F; Hilbert, Bryan; Trope, Gareth; Kalle, Wouter; Strappe, Padraig

2014-12-01

Equine adipose-derived mesenchymal stem cells (EADMSC) provide a unique cell-based approach for treatment of a variety of equine musculoskeletal injuries, via regeneration of diseased or damaged tissue, or the secretion of immunomodulatory molecules. These capabilities can be further enhanced by genetic modification using lentiviral vectors, which provide a safe and efficient method of gene delivery. We investigated the suitability of lentiviral vector technology for gene delivery into EADMSC, using GFP expressing lentiviral vectors pseudotyped with the G glycoprotein from the vesicular stomatitis virus (V-GFP) or, for the first time, the baculovirus gp64 envelope protein (G-GFP). In this study, we produced similarly high titre V-GFP and G-GFP lentiviral vectors. Flow cytometric analysis showed efficient transduction using V-GFP; however G-GFP exhibited a poor ability to transduce EADMSC. Transduction resulted in sustained GFP expression over four passages, with minimal effects on cell viability and doubling time, and an unaltered chondrogenic differentiation potential. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemoenzymatic Dynamic Kinetic Resolution: A Powerful Tool for the Preparation of Enantiomerically Pure Alcohols and Amines

PubMed Central

2015-01-01

Chemoenzymatic dynamic kinetic resolution (DKR) constitutes a convenient and efficient method to access enantiomerically pure alcohol and amine derivatives. This Perspective highlights the work carried out within this field during the past two decades and pinpoints important avenues for future research. First, the Perspective will summarize the more developed area of alcohol DKR, by delineating the way from the earliest proof-of-concept protocols to the current state-of-the-art systems that allows for the highly efficient and selective preparation of a wide range of enantiomerically pure alcohol derivatives. Thereafter, the Perspective will focus on the more challenging DKR of amines, by presenting the currently available homogeneous and heterogeneous methods and their respective limitations. In these two parts, significant attention will be dedicated to the design of efficient racemization methods as an important means of developing milder DKR protocols. In the final part of the Perspective, a brief overview of the research that has been devoted toward improving enzymes as biocatalysts is presented. PMID:25730714

Comparative study of glass tube and mist chamber sampling techniques for the analysis of gaseous carbonyl compounds

NASA Astrophysics Data System (ADS)

François, Stéphanie; Perraud, Véronique; Pflieger, Maryline; Monod, Anne; Wortham, Henri

In this work, glass tube and mist chamber sampling techniques using 2,4-dinitrophenylhydrazine as derivative agent for the analysis of gaseous carbonyl compounds are compared. Trapping efficiencies of formaldehyde, acetaldehyde, propionaldehyde, acetone, acrolein, glyoxal, crotonaldehyde, benzaldehyde, butyraldehyde and valeraldehyde are experimentally determined using a gas-phase generator. In addition to generalise our results to all atmospheric gaseous compounds and derivative agents, theoretical trapping efficiencies and enrichment factors are expressed taking into account mechanisms involved in the two kinds of traps. Theoretical and experimental results show that, as expected, the trapping efficiencies of the glass tube depend mainly on solubility of compounds. The results provide new information and better understanding of phenomena occurring in the mist chamber and the ability of this sampler to concentrate the samples. Hence, the mist chamber is the more convenient sampling method when the trapping is associated to a fast derivatisation of the compounds and the glass tube technique must be used to trap atmospheric compounds without simultaneous derivatisation.

Efficient Convex Optimization for Energy-Based Acoustic Sensor Self-Localization and Source Localization in Sensor Networks

PubMed Central

Yan, Yongsheng; Wang, Haiyan; Shen, Xiaohong; Leng, Bing; Li, Shuangquan

2018-01-01

The energy reading has been an efficient and attractive measure for collaborative acoustic source localization in practical application due to its cost saving in both energy and computation capability. The maximum likelihood problems by fusing received acoustic energy readings transmitted from local sensors are derived. Aiming to efficiently solve the nonconvex objective of the optimization problem, we present an approximate estimator of the original problem. Then, a direct norm relaxation and semidefinite relaxation, respectively, are utilized to derive the second-order cone programming, semidefinite programming or mixture of them for both cases of sensor self-location and source localization. Furthermore, by taking the colored energy reading noise into account, several minimax optimization problems are formulated, which are also relaxed via the direct norm relaxation and semidefinite relaxation respectively into convex optimization problems. Performance comparison with the existing acoustic energy-based source localization methods is given, where the results show the validity of our proposed methods. PMID:29883410

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

New anthracene derivatives as triplet acceptors for efficient green-to-blue low-power upconversion.

PubMed

Liang, Zuo-Qin; Sun, Bin; Ye, Chang-Qing; Wang, Xiao-Mei; Tao, Xu-Tang; Wang, Qin-Hua; Ding, Ping; Wang, Bao; Wang, Jing-Jing

2013-10-21

Three new anthracene derivatives [2-chloro-9,10-dip-tolylanthracene (DTACl), 9,10-dip-tolylanthracene-2-carbonitrile (DTACN), and 9,10-di(naphthalen-1-yl)anthracene-2-carbonitrile (DNACN)] were synthesized as triplet acceptors for low-power upconversion. Their linear absorption, single-photon-excited fluorescence, and upconversion fluorescence properties were studied. The acceptors exhibit high fluorescence yields in DMF. Selective excitation of the sensitizer Pd(II)octaethylporphyrin (PdOEP) in solution containing DTACl, DTACN, or DNA-CN at 532 nm with an ultralow excitation power density of 0.5 W cm(-2) results in anti-Stokes blue emission. The maximum upconversion quantum yield (Φ(UC) =17.4%) was obtained for the couple PdOEP/DTACl. In addition, the efficiency of the triplet-triplet energy transfer process was quantitatively studied by quenching experiments. Experimental results revealed that a highly effective acceptor for upconversion should combine high fluorescence quantum yields with efficient quenching of the sensitizer triplet. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water soluble cationic dextran derivatives containing poly(amidoamine) dendrons for efficient gene delivery.

PubMed

Mai, Kaijin; Zhang, Shanshan; Liang, Bing; Gao, Cong; Du, Wenjun; Zhang, Li-Ming

2015-06-05

To develop new dextran derivatives for efficient gene delivery, the conjugation of poly(amidoamine) dendrons onto biocompatible dextran was carried out by a Cu(I)-catalyzed azide-alkyne cycloaddition, as confirmed by FTIR and (1)H NMR analyses. For resultant dextran conjugates with various generations of poly(amidoamine) dendrons, their buffering capacity and in vitro cytotoxicity were evaluated by acid-base titration and MTT tests, respectively. In particular, their physicochemical characteristics for the complexation with plasmid DNA were investigated by the combined analyses from agarose gel electrophoresis, zeta potential, particle size, transmission electron microscopy and fluorescence emission spectra. Moreover, their complexes with plasmid DNA were studied with respect to their transfection efficiency in human embryonic kidney (HEK293) cell lines. In the case of a higher generation of poly(amidoamine) dendrons, such a dextran conjugate was found to have much lower cytotoxicity and better gene delivery capability when compared to branched polyethylenimine (bPEI, 25kDa), a commonly used gene vector. Copyright © 2015 Elsevier Ltd. All rights reserved.

Higher-order methods for simulations on quantum computers

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

Sornborger, A.T.; Stewart, E.D.

1999-09-01

To implement many-qubit gates for use in quantum simulations on quantum computers efficiently, we develop and present methods reexpressing exp[[minus]i(H[sub 1]+H[sub 2]+[center dot][center dot][center dot])[Delta]t] as a product of factors exp[[minus]iH[sub 1][Delta]t], exp[[minus]iH[sub 2][Delta]t],[hor ellipsis], which is accurate to third or fourth order in [Delta]t. The methods we derive are an extended form of the symplectic method, and can also be used for an integration of classical Hamiltonians on classical computers. We derive both integral and irrational methods, and find the most efficient methods in both cases. [copyright] [ital 1999] [ital The American Physical Society

Efficiency and Impact of Positive and Negative Magnetic Separation on Monocyte Derived Dendritic Cell Generation.

PubMed

Kowalewicz-Kulbat, Magdalena; Ograczyk, Elżbieta; Włodarczyk, Marcin; Krawczyk, Krzysztof; Fol, Marek

2016-06-01

The immunomagnetic separation technique is the basis of monocyte isolation and further generation of monocyte-derived dendritic cells. To compare the efficiency of monocyte positive and negative separation, concentration of beads, and their impact on generated dendritic cells. Monocytes were obtained using monoclonal antibody-coated magnetic beads followed the Ficoll-Paque gradient separation of mononuclear cell fraction from the peripheral blood of 6 healthy volunteers. CD14 expression was analyzed by flow cytometry. Both types of magnetic separation including recommended and reduced concentrations of beads did not affect the yield and the purity of monocytes and their surface CD14 expression. However, DCs originated from the "positively" separated monocytes had noticeable higher expression of CD80.

Structure–efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds

PubMed Central

Letort, Sophie; Bosco, Michaël; Cornelio, Benedetta; Brégier, Frédérique; Daulon, Sébastien; Gouhier, Géraldine

2017-01-01

New derivatives of cyclodextrins were prepared in order to determine the relative importance of the structural key elements involved in the degradation of organophosphorus nerve agents. To avoid a competitive inclusion between the organophosphorus substrate and the iodosobenzoate group, responsible for its degradation, the latter group had to be covalently bound to the cyclodextrin scaffold. Although the presence of the α nucleophile iodosobenzoate was a determinant in the hydrolysis process, an imidazole group was added to get a synergistic effect towards the degradation of the agents. The degradation efficiency was found to be dependent on the relative position of the heterocycle towards the reactive group as well as on the nature of the organophosphorus derivative. PMID:28382180

Structure-efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds.

PubMed

Letort, Sophie; Bosco, Michaël; Cornelio, Benedetta; Brégier, Frédérique; Daulon, Sébastien; Gouhier, Géraldine; Estour, François

2017-01-01

New derivatives of cyclodextrins were prepared in order to determine the relative importance of the structural key elements involved in the degradation of organophosphorus nerve agents. To avoid a competitive inclusion between the organophosphorus substrate and the iodosobenzoate group, responsible for its degradation, the latter group had to be covalently bound to the cyclodextrin scaffold. Although the presence of the α nucleophile iodosobenzoate was a determinant in the hydrolysis process, an imidazole group was added to get a synergistic effect towards the degradation of the agents. The degradation efficiency was found to be dependent on the relative position of the heterocycle towards the reactive group as well as on the nature of the organophosphorus derivative.

Enabling technologies and green processes in cyclodextrin chemistry.

PubMed

Cravotto, Giancarlo; Caporaso, Marina; Jicsinszky, Laszlo; Martina, Katia

2016-01-01

The design of efficient synthetic green strategies for the selective modification of cyclodextrins (CDs) is still a challenging task. Outstanding results have been achieved in recent years by means of so-called enabling technologies, such as microwaves, ultrasound and ball mills, that have become irreplaceable tools in the synthesis of CD derivatives. Several examples of sonochemical selective modification of native α-, β- and γ-CDs have been reported including heterogeneous phase Pd- and Cu-catalysed hydrogenations and couplings. Microwave irradiation has emerged as the technique of choice for the production of highly substituted CD derivatives, CD grafted materials and polymers. Mechanochemical methods have successfully furnished greener, solvent-free syntheses and efficient complexation, while flow microreactors may well improve the repeatability and optimization of critical synthetic protocols.

Alternate aircraft fuels: Prospects and operational implications

NASA Technical Reports Server (NTRS)

Witcofski, R. D.

1977-01-01

The potential use of coal-derived aviation fuels was assessed. The studies addressed the prices and thermal efficiencies associated with the production of coal-derived aviation kerosene, liquid methane and liquid hydrogen and the air terminal requirements and subsonic transport performance when utilizing liquid hydrogen. The fuel production studies indicated that liquid methane can be produced at a lower price and with a higher thermal efficiency than aviation kerosene or liquid hydrogen. Ground facilities of liquefaction, storage, distribution and refueling of liquid hydrogen fueled aircraft at airports appear technically feasibile. The aircraft studies indicate modest onboard energy savings for hydrogen compared to conventional fuels. Liquid hydrogen was found to be superior to both aviation kerosene and liquid methane from the standpoint of aircraft engine emissions.

Acceleration of Singlet Fission in an Aza-Derivative of TIPS-Pentacene.

PubMed

Herz, Julia; Buckup, Tiago; Paulus, Fabian; Engelhart, Jens; Bunz, Uwe H F; Motzkus, Marcus

2014-07-17

The influence of the carbon to nitrogen substitution on the photoinduced dynamics of TIPS-pentacene was investigated by ultrafast transient absorption measurements on spin-coated thin films in the visible and in the near-infrared spectral region. A global target analysis was performed to provide a detailed picture of the excited-state dynamics. We found that the chemical modification has a high impact on the triplet formation and leads to shorter dynamics; hence it speeds up the singlet fission process. A faster relaxation from the singlet into the triplet manifold implies a higher efficiency because other relaxation channels are avoided. The air-stable aza-derivatives have the potential to exceed the energy conversion efficiency of TIPS-pentacene.

High efficiency RF amplifier development over wide dynamic range for accelerator application

NASA Astrophysics Data System (ADS)

Mishra, Jitendra Kumar; Ramarao, B. V.; Pande, Manjiri M.; Joshi, Gopal; Sharma, Archana; Singh, Pitamber

2017-10-01

Superconducting (SC) cavities in an accelerating section are designed to have the same geometrical velocity factor (βg). For these cavities, Radio Frequency (RF) power needed to accelerate charged particles varies with the particle velocity factor (β). RF power requirement from one cavity to other can vary by 2-5 dB within the accelerating section depending on the energy gain in the cavity and beam current. In this paper, we have presented an idea to improve operating efficiency of the SC RF accelerators using envelope tracking technique. A study on envelope tracking technique without feedback is carried out on a 1 kW, 325 MHz, class B (conduction angle of 180 degrees) tuned load power amplifier (PA). We have derived expressions for the efficiency and power output for tuned load amplifier operating on the envelope tracking technique. From the derived expressions, it is observed that under constant load resistance to the device (MOSFET), optimum amplifier efficiency is invariant whereas output power varies with the square of drain bias voltage. Experimental results on 1 kW PA module show that its optimum efficiency is always greater than 62% with variation less than 5% from mean value over 7 dB dynamic range. Low power amplifier modules are the basic building block for the high power amplifiers. Therefore, results for 1 kW PA modules remain valid for the high power solid state amplifiers built using these PA modules. The SC RF accelerators using these constant efficiency power amplifiers can improve overall accelerator efficiency.

Nonlinear Stimulated Raman Exact Passage by Resonance-Locked Inverse Engineering

NASA Astrophysics Data System (ADS)

Dorier, V.; Gevorgyan, M.; Ishkhanyan, A.; Leroy, C.; Jauslin, H. R.; Guérin, S.

2017-12-01

We derive an exact and robust stimulated Raman process for nonlinear quantum systems driven by pulsed external fields. The external fields are designed with closed-form expressions from the inverse engineering of a given efficient and stable dynamics. This technique allows one to induce a controlled population inversion which surpasses the usual nonlinear stimulated Raman adiabatic passage efficiency.

Remarkable effect of halogenation of aromatic compounds on efficiency of nanowire formation through polymerization/crosslinking by high-energy single particle irradiation

NASA Astrophysics Data System (ADS)

Horio, Akifumi; Sakurai, Tsuneaki; Kayama, Kazuto; Lakshmi, G. B. V. S.; Kumar Avasthi, Devesh; Sugimoto, Masaki; Yamaki, Tetsuya; Chiba, Atsuya; Saito, Yuichi; Seki, Shu

2018-01-01

Irradiation of high-energy ion particles on organic films induced solid-state polymerization and crosslinking reactions of the materials along the ion trajectories, resulting in the formation of insoluble uniform nanowires with a precise diameter. The nanowires were isolated by the development process i.e. the irradiated film was immersed in organic solvents, and their morphology was visualized by atomic force microscopy. The target organic materials are 4-vinyltriphenylamine, poly(4-vinyltriphenylamine), and polystyrene derivatives with/without the partial substitutions by halogen atoms. It was found that 4-vinyltriphenylamines, in spite of their small molecular sizes, afforded nanowires more clearly than poly(4-vinyltriphenylamine)s. Moreover, the efficiency of demonstrated polymerization/crosslinking reactions obviously depends on the substituted halogen atom species. The averaged diameters of nanowires from bromo- or iodo- substituted 4-vinyltriphenylamine (9.3 and 9.4 nm, respectively) were larger than that obtained from simple 4-vinyltriphenylamine (6.8 nm). The remarkable effect of halogenation of aromatic compounds on the efficiency of the radiation-induced reactions was also observed for polystyrene derivatives. This contrast was considered to originate from the sum of the efficiency of elementary reactions including dissociative electron attachment.

Active oligonucleotides incorporating alkylating an agent as potential sequence- and base selective modifier of gene expression.

PubMed

Sasaki, S

2001-04-01

A number of cross-linking (alkylating) agents have been developed and incorporated into the oligonulceotides for sequence selective control of gene expression. Recently, potential application of such active oligonucleotides has been expanding from use for improvement of inhibition efficiency to new biotechnology that may enable chemical alteration of genetic information. These interests in active oligonucleotides have encouraged the generation of new cross-linking agents that exhibit high efficiency for application of either in vitro or in vivo. This mini review summarizes structures of alkylating agents, in particular, a new basic skeleton for cross-linking, a 2'-deoxyribose derivative of 2-amino-6-vinylpurine that has been recently developed by the author's group. The 2-amino-6-vinylpurine has been shown to form a complex with cytidine under acidic conditions, and brings the vinyl and the amino reactive groups into proximity to achieve efficient alkylation. A new strategy was designed so that the reactivity of 2-amino-6-vinylpurine can be induced from the corresponding phenylsulfoxide derivative within a duplex with the complementary strand. The validity of the new strategy has been proven by achievement of cytidine-selective cross-linking with remarkably efficiency.

Thermodynamics of the mesoscopic thermoelectric heat engine beyond the linear-response regime.

PubMed

Yamamoto, Kaoru; Hatano, Naomichi

2015-10-01

Mesoscopic thermoelectric heat engine is much anticipated as a device that allows us to utilize with high efficiency wasted heat inaccessible by conventional heat engines. However, the derivation of the heat current in this engine seems to be either not general or described too briefly, even inappropriately in some cases. In this paper, we give a clear-cut derivation of the heat current of the engine with suitable assumptions beyond the linear-response regime. It resolves the confusion in the definition of the heat current in the linear-response regime. After verifying that we can construct the same formalism as that of the cyclic engine, we find the following two interesting results within the Landauer-Büttiker formalism: the efficiency of the mesoscopic thermoelectric engine reaches the Carnot efficiency if and only if the transmission probability is finite at a specific energy and zero otherwise; the unitarity of the transmission probability guarantees the second law of thermodynamics, invalidating Benenti et al.'s argument in the linear-response regime that one could obtain a finite power with the Carnot efficiency under a broken time-reversal symmetry [Phys. Rev. Lett. 106, 230602 (2011)]. These results demonstrate how quantum mechanics constrains thermodynamics.

Analytic Couple Modeling Introducing Device Design Factor, Fin Factor, Thermal Diffusivity Factor, and Inductance Factor

NASA Technical Reports Server (NTRS)

Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

2014-01-01

A set of convenient thermoelectric device solutions have been derived in order to capture a number of factors which are previously only resolved with numerical techniques. The concise conversion efficiency equations derived from governing equations provide intuitive and straight-forward design guidelines. These guidelines allow for better device design without requiring detailed numerical modeling. The analytical modeling accounts for factors such as i) variable temperature boundary conditions, ii) lateral heat transfer, iii) temperature variable material properties, and iv) transient operation. New dimensionless parameters, similar to the figure of merit, are introduced including the device design factor, fin factor, thermal diffusivity factor, and inductance factor. These new device factors allow for the straight-forward description of phenomenon generally only captured with numerical work otherwise. As an example a device design factor of 0.38, which accounts for thermal resistance of the hot and cold shoes, can be used to calculate a conversion efficiency of 2.28 while the ideal conversion efficiency based on figure of merit alone would be 6.15. Likewise an ideal couple with efficiency of 6.15 will be reduced to 5.33 when lateral heat is accounted for with a fin factor of 1.0.

Scaling of electromagnetic transducers for shunt damping and energy harvesting

NASA Astrophysics Data System (ADS)

Elliott, Stephen J.; Zilletti, Michele

2014-04-01

In order for an electromagnetic transducer to operate well as either a mechanical shunt damper or as a vibration energy harvester, it must have good electromechanical coupling. A simple two-port analysis is used to derive a non-dimensional measure of electromechanical coupling, which must be large compared with unity for efficient operation in both of these applications. The two-port parameters for an inertial electromagnetic transducer are derived, from which this non-dimensional coupling parameter can be evaluated. The largest value that this parameter takes is approximately equal to the square of the magnetic flux density times the length of wire in the field, divided by the mechanical damping times the electrical resistance. This parameter is found to be only of the order of one for voice coil devices that weigh approximately 1 kg, and so such devices are generally not efficient, within the definition used here, in either of these applications. The non-dimensional coupling parameter is found to scale in approximate proportion to the device's characteristic length, however, and so although miniaturised devices are less efficient, greater efficiency can be obtained with large devices, such as those used to control civil engineering structures.

Genetically engineered oncolytic Newcastle disease virus mediates cytolysis of prostate cancer stem like cells.

PubMed

Raghunath, Shobana; Pudupakam, Raghavendra Sumanth; Allen, Adria; Biswas, Moanaro; Sriranganathan, Nammalwar

2017-10-20

Oncolytic virotherapy is a promising novel approach that overcomes the limitations posed by radiation and chemotherapy. In this study, the oncolytic efficacy of a recombinant Newcastle disease virus (rNDV) BC-KLQL-GFP, against prostate cancer stem-like/tumor initiating cells was evaluated. Xenograft derived prostaspheres (XPS) induced tumor more efficiently than monolayer cell derived prostaspheres (MCPS) in nude mice. Primary and secondary XPS show enhanced self-renewal and clonogenic potential compared to MCPS. XPS also expressed embryonic stem cell markers, such as Nanog, CD44 and Nestin. Further, prostate specific antigen (PSA) activated recombinant Newcastle Disease Virus (rNDV) was selectively cytotoxic to tumor derived DU145 prostaspheres. An effective concentration (EC 50 ) of 0.11-0.14 multiplicity of infection was sufficient to cause prostasphere cell death in serum free culture. DU145 tumor xenograft derived prostaspheres were used as tumor surrogates as they were enriched for a putative tumor initiating cell population. PSA activated rNDV was efficient in inducing cell death of cells and prostaspheres derived from primary xenografts ex-vivo, thus signifying a potential in vivo efficacy. The EC 50 (∼0.1 MOI) for cytolysis of tumor initiating cells was slightly higher than that was required for the parental cell line, but within the therapeutic margin for safety and efficacy. Copyright © 2017 Elsevier B.V. All rights reserved.

Sparse gammatone signal model optimized for English speech does not match the human auditory filters.

PubMed

Strahl, Stefan; Mertins, Alfred

2008-07-18

Evidence that neurosensory systems use sparse signal representations as well as improved performance of signal processing algorithms using sparse signal models raised interest in sparse signal coding in the last years. For natural audio signals like speech and environmental sounds, gammatone atoms have been derived as expansion functions that generate a nearly optimal sparse signal model (Smith, E., Lewicki, M., 2006. Efficient auditory coding. Nature 439, 978-982). Furthermore, gammatone functions are established models for the human auditory filters. Thus far, a practical application of a sparse gammatone signal model has been prevented by the fact that deriving the sparsest representation is, in general, computationally intractable. In this paper, we applied an accelerated version of the matching pursuit algorithm for gammatone dictionaries allowing real-time and large data set applications. We show that a sparse signal model in general has advantages in audio coding and that a sparse gammatone signal model encodes speech more efficiently in terms of sparseness than a sparse modified discrete cosine transform (MDCT) signal model. We also show that the optimal gammatone parameters derived for English speech do not match the human auditory filters, suggesting for signal processing applications to derive the parameters individually for each applied signal class instead of using psychometrically derived parameters. For brain research, it means that care should be taken with directly transferring findings of optimality for technical to biological systems.

Advancements in rationally designed PGM-free fuel cell catalysts derived from metal–organic frameworks

DOE PAGES

Barkholtz, Heather M.; Liu, Di -Jia

2016-11-14

Over the past several years, metal-organic framework (MOF)-derived platinum group metal free (PGM-free) electrocatalysts have gained considerable attention due to their high efficiency and low cost as potential replacement for platinum in catalyzing oxygen reduction reaction (ORR). In this review, we summarize the recent advancements in design, synthesis and characterization of MOF-derived ORR catalysts and their performances in acidic and alkaline media. As a result, we also discuss the key challenges such as durability and activity enhancement critical in moving forward this emerging electrocatalyst science.

Energy efficiency and allometry of movement of swimming and flying animals.

PubMed

Bale, Rahul; Hao, Max; Bhalla, Amneet Pal Singh; Patankar, Neelesh A

2014-05-27

Which animals use their energy better during movement? One metric to answer this question is the energy cost per unit distance per unit weight. Prior data show that this metric decreases with mass, which is considered to imply that massive animals are more efficient. Although useful, this metric also implies that two dynamically equivalent animals of different sizes will not be considered equally efficient. We resolve this longstanding issue by first determining the scaling of energy cost per unit distance traveled. The scale is found to be M(2/3) or M(1/2), where M is the animal mass. Second, we introduce an energy-consumption coefficient (CE) defined as energy per unit distance traveled divided by this scale. CE is a measure of efficiency of swimming and flying, analogous to how drag coefficient quantifies aerodynamic drag on vehicles. Derivation of the energy-cost scale reveals that the assumption that undulatory swimmers spend energy to overcome drag in the direction of swimming is inappropriate. We derive allometric scalings that capture trends in data of swimming and flying animals over 10-20 orders of magnitude by mass. The energy-consumption coefficient reveals that swimmers beyond a critical mass, and most fliers are almost equally efficient as if they are dynamically equivalent; increasingly massive animals are not more efficient according to the proposed metric. Distinct allometric scalings are discovered for large and small swimmers. Flying animals are found to require relatively more energy compared with swimmers.

Energy efficiency and allometry of movement of swimming and flying animals

PubMed Central

Bale, Rahul; Hao, Max; Bhalla, Amneet Pal Singh; Patankar, Neelesh A.

2014-01-01

Which animals use their energy better during movement? One metric to answer this question is the energy cost per unit distance per unit weight. Prior data show that this metric decreases with mass, which is considered to imply that massive animals are more efficient. Although useful, this metric also implies that two dynamically equivalent animals of different sizes will not be considered equally efficient. We resolve this longstanding issue by first determining the scaling of energy cost per unit distance traveled. The scale is found to be M2/3 or M1/2, where M is the animal mass. Second, we introduce an energy-consumption coefficient (CE) defined as energy per unit distance traveled divided by this scale. CE is a measure of efficiency of swimming and flying, analogous to how drag coefficient quantifies aerodynamic drag on vehicles. Derivation of the energy-cost scale reveals that the assumption that undulatory swimmers spend energy to overcome drag in the direction of swimming is inappropriate. We derive allometric scalings that capture trends in data of swimming and flying animals over 10–20 orders of magnitude by mass. The energy-consumption coefficient reveals that swimmers beyond a critical mass, and most fliers are almost equally efficient as if they are dynamically equivalent; increasingly massive animals are not more efficient according to the proposed metric. Distinct allometric scalings are discovered for large and small swimmers. Flying animals are found to require relatively more energy compared with swimmers. PMID:24821764

Second derivative in the model of classical binary system

NASA Astrophysics Data System (ADS)

Abubekerov, M. K.; Gostev, N. Yu.

2016-06-01

We have obtained an analytical expression for the second derivatives of the light curve with respect to geometric parameters in the model of eclipsing classical binary systems. These expressions are essentially efficient algorithm to calculate the numerical values of these second derivatives for all physical values of geometric parameters. Knowledge of the values of second derivatives of the light curve at some point provides additional information about asymptotical behaviour of the function near this point and can significantly improve the search for the best-fitting light curve through the use of second-order optimization method. We write the expression for the second derivatives in a form which is most compact and uniform for all values of the geometric parameters and so make it easy to write a computer program to calculate the values of these derivatives.

An analytic formula for H-infinity norm sensitivity with applications to control system design

NASA Technical Reports Server (NTRS)

Giesy, Daniel P.; Lim, Kyong B.

1992-01-01

An analytic formula for the sensitivity of singular value peak variation with respect to parameter variation is derived. As a corollary, the derivative of the H-infinity norm of a stable transfer function with respect to a parameter is presented. It depends on some of the first two derivatives of the transfer function with respect to frequency and the parameter. For cases when the transfer function has a linear system realization whose matrices depend on the parameter, analytic formulas for these first two derivatives are derived, and an efficient algorithm for calculating them is discussed. Examples are given which provide numerical verification of the H-infinity norm sensitivity formula and which demonstrate its utility in designing control systems satisfying H-infinity norm constraints. In the appendix, derivative formulas for singular values are paraphrased.

MUNICIPAL WASTE COMBUSTION MULTIPOLLUTANT STUDY EMISSION TEST REPORT, MAINE ENERGY RECOVERY COMPANY, RE- FUSE DERIVED FUEL FACILITY, BIDDEFORD, MAINE - VOLUME I: SUMMARY OF RESULTS

EPA Science Inventory

The report gives results of an emission test of a new municipal solid waste combustor, in Biddeford, ME, that burns refuse-derived fuel and is equipped with a lime spray dryer fabric filter (SD/FF) emission control system. ontrol efficiency of the SD/FF emission control system wa...

Domain Derivatives in Dielectric Rough Surface Scattering

DTIC Science & Technology

2015-01-01

and require the gradient of the objective function in the unknown model parameter vector at each stage of iteration. For large N, finite...differencing becomes numerically intensive, and an efficient alternative is domain differentiation in which the full gradient is obtained by solving a single...derivative calculation of the gradient for a locally perturbed dielectric interface. The method is non-variational, and algebraic in nature in that it

Development of growth and yield models for southern hardwoods: site index determinations

Treesearch

John Paul McTague; Daniel J. Robison; David O' Loughlin; Joseph Roise; Robert Kellison

2006-01-01

Growth and yield data from across 13 southern States, collected from 1967 to 2004 from fully-stocked even-aged southern hardwood forests on a variety of site types, was used to calculate site index curves. These derived curves provide an efficient means to evaluate the productivity-age relation which varies across many sites. These curves were derived for mixed-species...

Efficient biomass pretreatment using ionic liquids derived from lignin and hemicellulose

PubMed Central

Socha, Aaron M.; Parthasarathi, Ramakrishnan; Shi, Jian; Pattathil, Sivakumar; Whyte, Dorian; Bergeron, Maxime; George, Anthe; Tran, Kim; Stavila, Vitalie; Venkatachalam, Sivasankari; Hahn, Michael G.; Simmons, Blake A.; Singh, Seema

2014-01-01

Ionic liquids (ILs), solvents composed entirely of paired ions, have been used in a variety of process chemistry and renewable energy applications. Imidazolium-based ILs effectively dissolve biomass and represent a remarkable platform for biomass pretreatment. Although efficient, imidazolium cations are expensive and thus limited in their large-scale industrial deployment. To replace imidazolium-based ILs with those derived from renewable sources, we synthesized a series of tertiary amine-based ILs from aromatic aldehydes derived from lignin and hemicellulose, the major by-products of lignocellulosic biofuel production. Compositional analysis of switchgrass pretreated with ILs derived from vanillin, p-anisaldehyde, and furfural confirmed their efficacy. Enzymatic hydrolysis of pretreated switchgrass allowed for direct comparison of sugar yields and lignin removal between biomass-derived ILs and 1-ethyl-3-methylimidazolium acetate. Although the rate of cellulose hydrolysis for switchgrass pretreated with biomass-derived ILs was slightly slower than that of 1-ethyl-3-methylimidazolium acetate, 90–95% glucose and 70–75% xylose yields were obtained for these samples after 72-h incubation. Molecular modeling was used to compare IL solvent parameters with experimentally obtained compositional analysis data. Effective pretreatment of lignocellulose was further investigated by powder X-ray diffraction and glycome profiling of switchgrass cell walls. These studies showed different cellulose structural changes and differences in hemicellulose epitopes between switchgrass pretreatments with the aforementioned ILs. Our concept of deriving ILs from lignocellulosic biomass shows significant potential for the realization of a “closed-loop” process for future lignocellulosic biorefineries and has far-reaching economic impacts for other IL-based process technology currently using ILs synthesized from petroleum sources. PMID:25136131

Fluorescent Biphenyl Derivatives of Phenylalanine Suitable for Protein Modification

PubMed Central

Chen, Shengxi; Fahmi, Nour Eddine; Bhattacharya, Chandrabali; Wang, Lin; Jin, Yuguang; Benkovic, Stephen J.; Hecht, Sidney M.

2013-01-01

In a recent study, we demonstrated that structurally compact fluorophores incorporated into the side chains of amino acids could be introduced into dihydrofolate reductase from E. coli (ecDHFR) with minimal disruption of protein structure or function, even where the site of incorporation was within a folded region of the protein. The modified proteins could be employed for FRET measurements, providing sensitive monitors of changes in protein conformation. The very favorable results achieved in that study encouraged us to prepare additional fluorescent amino acids of potential utility for studying protein dynamics. Presently, we describe the synthesis and photophysical characterization of four positional isomers of biphenyl-phenylalanine, all of which were found to exhibit potentially useful fluorescent properties. All four phenylalanine derivatives were used to activate suppressor tRNA transcripts, and incorporated into multiple positions of ecDHFR. All phenylalanine derivatives were incorporated with good efficiency into position 16 of ecDHFR, and afforded modified proteins which consumed NADPH at rates up to about twice the rate measured for wild type. This phenomenon has been noted on a number of occasions previously and shown to be due to an increase in the off-rate of tetrahydrofolate from the enzyme, altering a step that is normally rate limiting. When introduced into sterically accessible position 49, the four phenylalanine derivatives afforded DHFRs having catalytic function comparable to wild type. The four phenylalanine derivatives were also introduced into position 115 of ecDHFR, which is known to be a folded region of the protein less tolerant of structural alteration. As anticipated, significant differences were noted in the catalytic efficiencies of the derived proteins. The ability of two of the sizeable biphenyl-phenylalanine derivatives to be accommodated at position 115 with minimal perturbation of DHFR function is attributed to rotational flexibility about the biphenyl bonds. PMID:24152169

Fiber-coupling efficiency of Gaussian-Schell model beams through an ocean to fiber optical communication link

NASA Astrophysics Data System (ADS)

Hu, Beibei; Shi, Haifeng; Zhang, Yixin

2018-06-01

We theoretically study the fiber-coupling efficiency of Gaussian-Schell model beams propagating through oceanic turbulence. The expression of the fiber-coupling efficiency is derived based on the spatial power spectrum of oceanic turbulence and the cross-spectral density function. Our work shows that the salinity fluctuation has a greater impact on the fiber-coupling efficiency than temperature fluctuation does. We can select longer λ in the "ocean window" and higher spatial coherence of light source to improve the fiber-coupling efficiency of the communication link. We also can achieve the maximum fiber-coupling efficiency by choosing design parameter according specific oceanic turbulence condition. Our results are able to help the design of optical communication link for oceanic turbulence to fiber sensor.

High efficiency solar cell processing

NASA Technical Reports Server (NTRS)

Ho, F.; Iles, P. A.

1985-01-01

At the time of writing, cells made by several groups are approaching 19% efficiency. General aspects of the processing required for such cells are discussed. Most processing used for high efficiency cells is derived from space-cell or concentrator cell technology, and recent advances have been obtained from improved techniques rather than from better understanding of the limiting mechanisms. Theory and modeling are fairly well developed, and adequate to guide further asymptotic increases in performance of near conventional cells. There are several competitive cell designs with promise of higher performance ( 20%) but for these designs further improvements are required. The available cell processing technology to fabricate high efficiency cells is examined.

Calorimetric Measurement for Internal Conversion Efficiency of Photovoltaic Cells/Modules Based on Electrical Substitution Method

NASA Astrophysics Data System (ADS)

Saito, Terubumi; Tatsuta, Muneaki; Abe, Yamato; Takesawa, Minato

2018-02-01

We have succeeded in the direct measurement for solar cell/module internal conversion efficiency based on a calorimetric method or electrical substitution method by which the absorbed radiant power is determined by replacing the heat absorbed in the cell/module with the electrical power. The technique is advantageous in that the reflectance and transmittance measurements, which are required in the conventional methods, are not necessary. Also, the internal quantum efficiency can be derived from conversion efficiencies by using the average photon energy. Agreements of the measured data with the values estimated from the nominal values support the validity of this technique.

An efficient method for computation of the manipulator inertia matrix

NASA Technical Reports Server (NTRS)

Fijany, Amir; Bejczy, Antal K.

1989-01-01

An efficient method of computation of the manipulator inertia matrix is presented. Using spatial notations, the method leads to the definition of the composite rigid-body spatial inertia, which is a spatial representation of the notion of augmented body. The previously proposed methods, the physical interpretations leading to their derivation, and their redundancies are analyzed. The proposed method achieves a greater efficiency by eliminating the redundancy in the intrinsic equations as well as by a better choice of coordinate frame for their projection. In this case, removing the redundancy leads to greater efficiency of the computation in both serial and parallel senses.

Human Cartilage-Derived Progenitor Cells From Committed Chondrocytes for Efficient Cartilage Repair and Regeneration

PubMed Central

Jiang, Yangzi; Cai, Youzhi; Zhang, Wei; Yin, Zi; Hu, Changchang; Tong, Tong; Lu, Ping; Zhang, Shufang; Neculai, Dante

2016-01-01

Articular cartilage is not a physiologically self-renewing tissue. Injury of cartilage often progresses from the articular surface to the subchondral bone, leading to pathogenesis of tissue degenerative diseases, such as osteoarthritis. Therapies to treat cartilage defects using autologous chondrocyte-based tissue engineering have been developed and used for more than 20 years; however, the challenge of chondrocyte expansion in vitro remains. A promising cell source, cartilage stem/progenitor cells (CSPCs), has attracted recent attention. Because their origin and identity are still unclear, the application potential of CSPCs is under active investigation. Here we have captured the emergence of a group of stem/progenitor cells derived from adult human chondrocytes, highlighted by dynamic changes in expression of the mature chondrocyte marker, COL2, and mesenchymal stromal/stem cell (MSC) marker, CD146. These cells are termed chondrocyte-derived progenitor cells (CDPCs). The stem cell-like potency and differentiation status of CDPCs were determined by physical and biochemical cues during culture. A low-density, low-glucose 2-dimensional culture condition (2DLL) was critical for the emergence and proliferation enhancement of CDPCs. CDPCs showed similar phenotype as bone marrow mesenchymal stromal/stem cells but exhibited greater chondrogenic potential. Moreover, the 2DLL-cultured CDPCs proved efficient in cartilage formation both in vitro and in vivo and in repairing large knee cartilage defects (6–13 cm2) in 15 patients. These findings suggest a phenotype conversion between chondrocytes and CDPCs and provide conditions that promote the conversion. These insights expand our understanding of cartilage biology and may enhance the success of chondrocyte-based therapies. Significance Injury of cartilage, a non-self-repairing tissue, often progresses to pathogenesis of degenerative joint diseases, such as osteoarthritis. Although tissue-derived stem cells have been shown to contribute to tissue renewal and homeostasis, the derivation, biological function, and application potential of stem/progenitor cells found in adult human articular cartilage are incompletely understood. This study reports the derivation of a population of cartilage stem/progenitor cells from fully differentiated chondrocytes under specific culture conditions, which have the potential to reassume their chondrocytic phenotype for efficient cartilage regeneration. These findings support the possibility of using in vitro amplified chondrocyte-derived progenitor cells for joint cartilage repair. PMID:27130221

Artificial MicroRNA-Based Specific Gene Silencing of Grain Hardness Genes in Polyploid Cereals Appeared to Be Not Stable Over Transgenic Plant Generations

PubMed Central

Gasparis, Sebastian; Kała, Maciej; Przyborowski, Mateusz; Orczyk, Waclaw; Nadolska-Orczyk, Anna

2017-01-01

Gene silencing by RNA interference is a particularly important tool in the study of gene function in polyploid cereal species for which the collections of natural or induced mutants are very limited. Previously we have been testing small interfering RNA-based approach of gene silencing in wheat and triticale. In this research, artificial microRNAs (amiRs) were studied in the same species and the same target genes to compare effectiveness of both gene silencing pathways. amiR cassettes were designed to silence Puroindoline a (Pina) and Puroindoline b (Pinb) hardness genes in wheat and their orthologues Secaloindoline a (Sina) and Secaloindoline b (Sinb) genes in triticale. Each of the two cassettes contained 21 nt microRNA (miR) precursor derived from conserved regions of Pina/Sina or Pinb/Sinb genes, respectively. Transgenic plants were obtained with high efficiency in two cultivars of wheat and one cultivar of triticale after using the Pinb-derived amiR vector for silencing of Pinb or Sinb, respectively. Lack of transgenic plants in wheat or very low transformation efficiency in triticale was observed using the Pina-derived amiR cassette, despite large numbers of embryos attempted. Silencing of Pinb in wheat and Sinb in triticale was highly efficient in the T1 generation. The transcript level of Pinb in wheat was reduced up to 92% and Sinb in triticale was reduced up to 98%. Moreover, intended silencing of Pinb/Sinb with Pinb-derived amiR cassette was highly correlated with simultaneous silencing of Pina/Sina in the same transgenic plants. High downregulation of Pinb/Pina genes in T1 plants of wheat and Sinb/Sina genes in T1 plants of triticale was associated with strong expression of Pinb-derived amiR. Silencing of the target genes correlated with increased grain hardness in both species. Total protein content in the grains of transgenic wheat was significantly lower. Although, the Pinb-derived amiR cassette was stably inherited in the T2 generation of wheat and triticale the silencing effect including strongly decreased expression of silenced genes as well as strong expression of Pinb-derived amiR was not transmitted. Advantages and disadvantages of posttranscriptional silencing of target genes by means of amiR and siRNA-based approaches in polyploid cereals are discussed. PMID:28119710

Human Cartilage-Derived Progenitor Cells From Committed Chondrocytes for Efficient Cartilage Repair and Regeneration.

PubMed

Jiang, Yangzi; Cai, Youzhi; Zhang, Wei; Yin, Zi; Hu, Changchang; Tong, Tong; Lu, Ping; Zhang, Shufang; Neculai, Dante; Tuan, Rocky S; Ouyang, Hong Wei

2016-06-01

Articular cartilage is not a physiologically self-renewing tissue. Injury of cartilage often progresses from the articular surface to the subchondral bone, leading to pathogenesis of tissue degenerative diseases, such as osteoarthritis. Therapies to treat cartilage defects using autologous chondrocyte-based tissue engineering have been developed and used for more than 20 years; however, the challenge of chondrocyte expansion in vitro remains. A promising cell source, cartilage stem/progenitor cells (CSPCs), has attracted recent attention. Because their origin and identity are still unclear, the application potential of CSPCs is under active investigation. Here we have captured the emergence of a group of stem/progenitor cells derived from adult human chondrocytes, highlighted by dynamic changes in expression of the mature chondrocyte marker, COL2, and mesenchymal stromal/stem cell (MSC) marker, CD146. These cells are termed chondrocyte-derived progenitor cells (CDPCs). The stem cell-like potency and differentiation status of CDPCs were determined by physical and biochemical cues during culture. A low-density, low-glucose 2-dimensional culture condition (2DLL) was critical for the emergence and proliferation enhancement of CDPCs. CDPCs showed similar phenotype as bone marrow mesenchymal stromal/stem cells but exhibited greater chondrogenic potential. Moreover, the 2DLL-cultured CDPCs proved efficient in cartilage formation both in vitro and in vivo and in repairing large knee cartilage defects (6-13 cm(2)) in 15 patients. These findings suggest a phenotype conversion between chondrocytes and CDPCs and provide conditions that promote the conversion. These insights expand our understanding of cartilage biology and may enhance the success of chondrocyte-based therapies. Injury of cartilage, a non-self-repairing tissue, often progresses to pathogenesis of degenerative joint diseases, such as osteoarthritis. Although tissue-derived stem cells have been shown to contribute to tissue renewal and homeostasis, the derivation, biological function, and application potential of stem/progenitor cells found in adult human articular cartilage are incompletely understood. This study reports the derivation of a population of cartilage stem/progenitor cells from fully differentiated chondrocytes under specific culture conditions, which have the potential to reassume their chondrocytic phenotype for efficient cartilage regeneration. These findings support the possibility of using in vitro amplified chondrocyte-derived progenitor cells for joint cartilage repair. ©AlphaMed Press.

Topics in quantum chaos

NASA Astrophysics Data System (ADS)

Jordan, Andrew Noble

2002-09-01

In this dissertation, we study the quantum mechanics of classically chaotic dynamical systems. We begin by considering the decoherence effects a quantum chaotic system has on a simple quantum few state system. Typical time evolution of a quantum system whose classical limit is chaotic generates structures in phase space whose size is much smaller than Planck's constant. A naive application of Heisenberg's uncertainty principle indicates that these structures are not physically relevant. However, if we take the quantum chaotic system in question to be an environment which interacts with a simple two state quantum system (qubit), we show that these small phase-space structures cause the qubit to generically lose quantum coherence if and only if the environment has many degrees of freedom, such as a dilute gas. This implies that many-body environments may be crucial for the phenomenon of quantum decoherence. Next, we turn to an analysis of statistical properties of time correlation functions and matrix elements of quantum chaotic systems. A semiclassical evaluation of matrix elements of an operator indicates that the dominant contribution will be related to a classical time correlation function over the energy surface. For a highly chaotic class of dynamics, these correlation functions may be decomposed into sums of Ruelle resonances, which control exponential decay to the ergodic distribution. The theory is illustrated both numerically and theoretically on the Baker map. For this system, we are able to isolate individual Ruelle modes. We further consider dynamical systems whose approach to ergodicity is given by a power law rather than an exponential in time. We propose a billiard with diffusive boundary conditions, whose classical solution may be calculated analytically. We go on to compare the exact solution with an approximation scheme, as well calculate asympotic corrections. Quantum spectral statistics are calculated assuming the validity of the Again, Altshuler and Andreev ansatz. We find singular behavior of the two point spectral correlator in the limit of small spacing. Finally, we analyse the effect that slow decay to ergodicity has on the structure of the quantum propagator, as well as wavefunction localization. We introduce a statistical quantum description of systems that are composed of both an orderly region and a random region. By averaging over the random region only, we find that measures of localization in momentum space semiclassically diverge with the dimension of the Hilbert space. We illustrate this numerically with quantum maps and suggest various other systems where this behavior should be important.

High‐Performance Lithium‐Oxygen Battery Electrolyte Derived from Optimum Combination of Solvent and Lithium Salt

PubMed Central

Ahn, Su Mi; Suk, Jungdon; Kim, Do Youb; Kim, Hwan Kyu

2017-01-01

Abstract To fabricate a sustainable lithium‐oxygen (Li‐O2) battery, it is crucial to identify an optimum electrolyte. Herein, it is found that tetramethylene sulfone (TMS) and lithium nitrate (LiNO3) form the optimum electrolyte, which greatly reduces the overpotential at charge, exhibits superior oxygen efficiency, and allows stable cycling for 100 cycles. Linear sweep voltammetry (LSV) and differential electrochemical mass spectrometry (DEMS) analyses reveal that neat TMS is stable to oxidative decomposition and exhibit good compatibility with a lithium metal. But, when TMS is combined with typical lithium salts, its performance is far from satisfactory. However, the TMS electrolyte containing LiNO3 exhibits a very low overpotential, which minimizes the side reactions and shows high oxygen efficiency. LSV‐DEMS study confirms that the TMS‐LiNO3 electrolyte efficiently produces NO2 −, which initiates a redox shuttle reaction. Interestingly, this NO2 −/NO2 redox reaction derived from the LiNO3 salt is not very effective in solvents other than TMS. Compared with other common Li‐O2 solvents, TMS seems optimum solvent for the efficient use of LiNO3 salt. Good compatibility with lithium metal, high dielectric constant, and low donicity of TMS are considered to be highly favorable to an efficient NO2 −/NO2 redox reaction, which results in a high‐performance Li‐O2 battery. PMID:29051863

Technical assessment of discarded tires gasification as alternative technology for electricity generation.

PubMed

Machin, Einara Blanco; Pedroso, Daniel Travieso; de Carvalho, João Andrade

2017-10-01

Concern about contamination associated with the disposal of tires has led to the search for technologies to reuse discarded tires, which include the use of Tire Derived Fuel (TDF) as fuel in advanced thermal-conversion processes, this allows the energy use of these wastes at affordable costs and reduces the environmental impact on scrap tires disposal. A theoretical assessment of the technical viability of TDF gasification for electric and thermal power generation, from the producer gas combustion in an internal combustion engine and in a gas turbine, was performed. The combustion of producer gas derived from the gasification of TDF in an internal combustion engine driving a generator (ICE-G) appears as the more efficient route for electricity generation when compared with the efficiency obtained with the use of gas turbine (GT-G). A higher global efficiency, considering the electric and thermal generation efficiency can be expected with the use of TDF producer gas in GT-G, where is expected an overall efficiency of 77.49%. The assessment shows that is possible produces up to 7.67MJ and 10.62MJ of electric and thermal energy per kilogram of TDF gasified using an ICE-G and up to 6.06MJ and 13.03MJ of electric and thermal energy respectively per kilogram of gasified TDF using a GT-G. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative evaluation of rRNA depletion procedures for the improved analysis of bacterial biofilm and mixed pathogen culture transcriptomes

PubMed Central

Petrova, Olga E.; Garcia-Alcalde, Fernando; Zampaloni, Claudia; Sauer, Karin

2017-01-01

Global transcriptomic analysis via RNA-seq is often hampered by the high abundance of ribosomal (r)RNA in bacterial cells. To remove rRNA and enrich coding sequences, subtractive hybridization procedures have become the approach of choice prior to RNA-seq, with their efficiency varying in a manner dependent on sample type and composition. Yet, despite an increasing number of RNA-seq studies, comparative evaluation of bacterial rRNA depletion methods has remained limited. Moreover, no such study has utilized RNA derived from bacterial biofilms, which have potentially higher rRNA:mRNA ratios and higher rRNA carryover during RNA-seq analysis. Presently, we evaluated the efficiency of three subtractive hybridization-based kits in depleting rRNA from samples derived from biofilm, as well as planktonic cells of the opportunistic human pathogen Pseudomonas aeruginosa. Our results indicated different rRNA removal efficiency for the three procedures, with the Ribo-Zero kit yielding the highest degree of rRNA depletion, which translated into enhanced enrichment of non-rRNA transcripts and increased depth of RNA-seq coverage. The results indicated that, in addition to improving RNA-seq sensitivity, efficient rRNA removal enhanced detection of low abundance transcripts via qPCR. Finally, we demonstrate that the Ribo-Zero kit also exhibited the highest efficiency when P. aeruginosa/Staphylococcus aureus co-culture RNA samples were tested. PMID:28117413

Multicolor fluorescent biosensor for multiplexed detection of DNA.

PubMed

Hu, Rong; Liu, Tao; Zhang, Xiao-Bing; Huan, Shuang-Yan; Wu, Cuichen; Fu, Ting; Tan, Weihong

2014-05-20

Development of efficient methods for highly sensitive and rapid screening of specific oligonucleotide sequences is essential to the early diagnosis of serious diseases. In this work, an aggregated cationic perylene diimide (PDI) derivative was found to efficiently quench the fluorescence emission of a variety of anionic oligonucleotide-labeled fluorophores that emit at wavelengths from the visible to NIR region. This broad-spectrum quencher was then adopted to develop a multicolor biosensor via a label-free approach for multiplexed fluorescent detection of DNA. The aggregated perylene derivative exhibits a very high quenching efficiency on all ssDNA-labeled dyes associated with biosensor detection, having efficiency values of 98.3 ± 0.9%, 97 ± 1.1%, and 98.2 ± 0.6% for FAM, TAMRA, and Cy5, respectively. An exonuclease-assisted autocatalytic target recycling amplification was also integrated into the sensing system. High quenching efficiency combined with autocatalytic target recycling amplification afforded the biosensor with high sensitivity toward target DNA, resulting in a detection limit of 20 pM, which is about 50-fold lower than that of traditional unamplified homogeneous fluorescent assay methods. The quencher did not interfere with the catalytic activity of nuclease, and the biosensor could be manipulated in either preaddition or postaddition manner with similar sensitivity. Moreover, the proposed sensing system allows for simultaneous and multicolor analysis of several oligonucleotides in homogeneous solution, demonstrating its potential application in the rapid screening of multiple biotargets.

High-Performance Lithium-Oxygen Battery Electrolyte Derived from Optimum Combination of Solvent and Lithium Salt.

PubMed

Ahn, Su Mi; Suk, Jungdon; Kim, Do Youb; Kang, Yongku; Kim, Hwan Kyu; Kim, Dong Wook

2017-10-01

To fabricate a sustainable lithium-oxygen (Li-O 2 ) battery, it is crucial to identify an optimum electrolyte. Herein, it is found that tetramethylene sulfone (TMS) and lithium nitrate (LiNO 3 ) form the optimum electrolyte, which greatly reduces the overpotential at charge, exhibits superior oxygen efficiency, and allows stable cycling for 100 cycles. Linear sweep voltammetry (LSV) and differential electrochemical mass spectrometry (DEMS) analyses reveal that neat TMS is stable to oxidative decomposition and exhibit good compatibility with a lithium metal. But, when TMS is combined with typical lithium salts, its performance is far from satisfactory. However, the TMS electrolyte containing LiNO 3 exhibits a very low overpotential, which minimizes the side reactions and shows high oxygen efficiency. LSV-DEMS study confirms that the TMS-LiNO 3 electrolyte efficiently produces NO 2 - , which initiates a redox shuttle reaction. Interestingly, this NO 2 - /NO 2 redox reaction derived from the LiNO 3 salt is not very effective in solvents other than TMS. Compared with other common Li-O 2 solvents, TMS seems optimum solvent for the efficient use of LiNO 3 salt. Good compatibility with lithium metal, high dielectric constant, and low donicity of TMS are considered to be highly favorable to an efficient NO 2 - /NO 2 redox reaction, which results in a high-performance Li-O 2 battery.

Algae in fish feed: performances and fatty acid metabolism in juvenile Atlantic Salmon.

PubMed

Norambuena, Fernando; Hermon, Karen; Skrzypczyk, Vanessa; Emery, James A; Sharon, Yoni; Beard, Alastair; Turchini, Giovanni M

2015-01-01

Algae are at the base of the aquatic food chain, producing the food resources that fish are adapted to consume. Previous studies have proven that the inclusion of small amounts (<10% of the diet) of algae in fish feed (aquafeed) resulted in positive effects in growth performance and feed utilisation efficiency. Marine algae have also been shown to possess functional activities, helping in the mediation of lipid metabolism, and therefore are increasingly studied in human and animal nutrition. The aim of this study was to assess the potentials of two commercially available algae derived products (dry algae meal), Verdemin (derived from Ulva ohnoi) and Rosamin (derived from diatom Entomoneis spp.) for their possible inclusion into diet of Atlantic Salmon (Salmo salar). Fish performances, feed efficiency, lipid metabolism and final product quality were assessed to investigated the potential of the two algae products (in isolation at two inclusion levels, 2.5% and 5%, or in combination), in experimental diets specifically formulated with low fish meal and fish oil content. The results indicate that inclusion of algae product Verdemin and Rosamin at level of 2.5 and 5.0% did not cause any major positive, nor negative, effect in Atlantic Salmon growth and feed efficiency. An increase in the omega-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) content in whole body of fish fed 5% Rosamin was observed.

Highly efficient transition metal and nitrogen co-doped carbide-derived carbon electrocatalysts for anion exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Ratso, Sander; Kruusenberg, Ivar; Käärik, Maike; Kook, Mati; Puust, Laurits; Saar, Rando; Leis, Jaan; Tammeveski, Kaido

2018-01-01

The search for an efficient electrocatalyst for oxygen reduction reaction (ORR) to replace platinum in fuel cell cathode materials is one of the hottest topics in electrocatalysis. Among the many non-noble metal catalysts, metal/nitrogen/carbon composites made by pyrolysis of cheap materials are the most promising with control over the porosity and final structure of the catalyst a crucial point. In this work we show a method of producing a highly active ORR catalyst in alkaline media with a controllable porous structure using titanium carbide derived carbon as a base structure and dicyandiamide along with FeCl3 or CoCl2 as the dopants. The resulting transition metal-nitrogen co-doped carbide derived carbon (M/N/CDC) catalyst is highly efficient for ORR electrocatalysis with the activity in 0.1 M KOH approaching that of commercial 46.1 wt.% Pt/C. The catalyst materials are also investigated by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy to characterise the changes in morphology and composition causing the raise in electrochemical activity. MEA performance of M/N/CDC cathode materials in H2/O2 alkaline membrane fuel cell is tested with the highest power density reached being 80 mW cm-2 compared to 90 mW cm-2 for Pt/C.

Intracellular sorting of differently charged chitosan derivatives and chitosan-based nanoparticles

NASA Astrophysics Data System (ADS)

Zubareva, A. A.; Shcherbinina, T. S.; Varlamov, V. P.; Svirshchevskaya, E. V.

2015-04-01

Chitosan (Chi) is a biodegradable nontoxic polycation with multiple reactive groups that is easily used to obtain derivatives with a desired charge and hydrophobic properties. The aim of this work was to study the intracellular traffic of positively charged hexanoyl-chitosan (HC) or HC-based nanoparticles (HCNPs) and negatively charged succinoyl-chitosan (SC) and SCNPs in epithelial and macrophage cell lines. By using flow cytometry we demonstrated that positively charged HC adhered to cell membranes quicker and more efficiently than negatively charged SC or NPs. However confocal studies showed that SC and SCNPs penetrated cells much more efficiently than HC while HCNPs did not enter the epithelial cells. Macrophages also phagocyted better negatively charged material but were able to engulf both HC and HCNPs. Upon entering the cells, SC and SCNPs were co-localized with endosomes and lysosomes while HC was found in mitochondria and, to a lesser extent, in lysosomes of epithelial cells. Macrophages, RAW264.7, more efficiently transported all Chi samples to the lysosomal compartment while some positively charged material was still found in mitochondria. Incubation of Chi derivatives and ChiNPs at pH specific to mitochondria (8.0) and lysosomes (4.5) demonstrated the neutralization of Chi charge. We concluded that epithelial cells and, to a lesser extent, macrophages sort charged material to the organelles neutralizing Chi charge.

Advanced Applications of Adifor 3.0 for Efficient Calculation of First-and Second-Order CFD Sensitivity Derivatives

NASA Technical Reports Server (NTRS)

Taylor, Arthur C., III

2004-01-01

This final report will document the accomplishments of the work of this project. 1) The incremental-iterative (II) form of the reverse-mode (adjoint) method for computing first-order (FO) aerodynamic sensitivity derivatives (SDs) has been successfully implemented and tested in a 2D CFD code (called ANSERS) using the reverse-mode capability of ADIFOR 3.0. These preceding results compared very well with similar SDS computed via a black-box (BB) application of the reverse-mode capability of ADIFOR 3.0, and also with similar SDs calculated via the method of finite differences. 2) Second-order (SO) SDs have been implemented in the 2D ASNWERS code using the very efficient strategy that was originally proposed (but not previously tested) of Reference 3, Appendix A. Furthermore, these SO SOs have been validated for accuracy and computational efficiency. 3) Studies were conducted in Quasi-1D and 2D concerning the smoothness (or lack of smoothness) of the FO and SO SD's for flows with shock waves. The phenomenon is documented in the publications of this study (listed subsequently), however, the specific numerical mechanism which is responsible for this unsmoothness phenomenon was not discovered. 4) The FO and SO derivatives for Quasi-1D and 2D flows were applied to predict aerodynamic design uncertainties, and were also applied in robust design optimization studies.

Formation of DNA Adducts by Ellipticine and Its Micellar Form in Rats — A Comparative Study

PubMed Central

Stiborova, Marie; Manhartova, Zuzana; Hodek, Petr; Adam, Vojtech; Kizek, Rene; Frei, Eva

2014-01-01

The requirements for early diagnostics as well as effective treatment of cancer diseases have increased the pressure on development of efficient methods for targeted drug delivery as well as imaging of the treatment success. One of the most recent approaches covering the drug delivery aspects is benefitting from the unique properties of nanomaterials. Ellipticine and its derivatives are efficient anticancer compounds that function through multiple mechanisms. Formation of covalent DNA adducts after ellipticine enzymatic activation is one of the most important mechanisms of its pharmacological action. In this study, we investigated whether ellipticine might be released from its micellar (encapsulated) form to generate covalent adducts analogous to those formed by free ellipticine. The 32P-postlabeling technique was used as a useful imaging method to detect and quantify covalent ellipticine-derived DNA adducts. We compared the efficiencies of free ellipticine and its micellar form (the poly(ethylene oxide)-block-poly(allyl glycidyl ether) (PAGE-PEO) block copolymer, P 119 nanoparticles) to form ellipticine-DNA adducts in rats in vivo. Here, we demonstrate for the first time that treatment of rats with ellipticine in micelles resulted in formation of ellipticine-derived DNA adducts in vivo and suggest that a gradual release of ellipticine from its micellar form might produce the enhanced permeation and retention effect of this ellipticine-micellar delivery system. PMID:25479328

Theory and practical application of out of sequence measurements with results for multi-static tracking

NASA Astrophysics Data System (ADS)

Iny, David

2007-09-01

This paper addresses the out-of-sequence measurement (OOSM) problem associated with multiple platform tracking systems. The problem arises due to different transmission delays in communication of detection reports across platforms. Much of the literature focuses on the improvement to the state estimate by incorporating the OOSM. As the time lag increases, there is diminishing improvement to the state estimate. However, this paper shows that optimal processing of OOSMs may still be beneficial by improving data association as part of a multi-target tracker. This paper derives exact multi-lag algorithms with the property that the standard log likelihood track scoring is independent of the order in which the measurements are processed. The orthogonality principle is applied to generalize the method of Bar- Shalom in deriving the exact A1 algorithm for 1-lag estimation. Theory is also developed for optimal filtering of time averaged measurements and measurements correlated through periodic updates of a target aim-point. An alternative derivation of the multi-lag algorithms is also achieved using an efficient variant of the augmented state Kalman filter (AS-KF). This results in practical and reasonably efficient multi-lag algorithms. Results are compared to a well known ad hoc algorithm for incorporating OOSMs. Finally, the paper presents some simulated multi-target multi-static scenarios where there is a benefit to processing the data out of sequence in order to improve pruning efficiency.

Algae in Fish Feed: Performances and Fatty Acid Metabolism in Juvenile Atlantic Salmon

PubMed Central

Norambuena, Fernando; Hermon, Karen; Skrzypczyk, Vanessa; Emery, James A.; Sharon, Yoni; Beard, Alastair; Turchini, Giovanni M.

2015-01-01

Algae are at the base of the aquatic food chain, producing the food resources that fish are adapted to consume. Previous studies have proven that the inclusion of small amounts (<10% of the diet) of algae in fish feed (aquafeed) resulted in positive effects in growth performance and feed utilisation efficiency. Marine algae have also been shown to possess functional activities, helping in the mediation of lipid metabolism, and therefore are increasingly studied in human and animal nutrition. The aim of this study was to assess the potentials of two commercially available algae derived products (dry algae meal), Verdemin (derived from Ulva ohnoi) and Rosamin (derived from diatom Entomoneis spp.) for their possible inclusion into diet of Atlantic Salmon (Salmo salar). Fish performances, feed efficiency, lipid metabolism and final product quality were assessed to investigated the potential of the two algae products (in isolation at two inclusion levels, 2.5% and 5%, or in combination), in experimental diets specifically formulated with low fish meal and fish oil content. The results indicate that inclusion of algae product Verdemin and Rosamin at level of 2.5 and 5.0% did not cause any major positive, nor negative, effect in Atlantic Salmon growth and feed efficiency. An increase in the omega-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) content in whole body of fish fed 5% Rosamin was observed. PMID:25875839

An efficient method for solving the steady Euler equations

NASA Technical Reports Server (NTRS)

Liou, M. S.

1986-01-01

An efficient numerical procedure for solving a set of nonlinear partial differential equations is given, specifically for the steady Euler equations. Solutions of the equations were obtained by Newton's linearization procedure, commonly used to solve the roots of nonlinear algebraic equations. In application of the same procedure for solving a set of differential equations we give a theorem showing that a quadratic convergence rate can be achieved. While the domain of quadratic convergence depends on the problems studied and is unknown a priori, we show that firstand second-order derivatives of flux vectors determine whether the condition for quadratic convergence is satisfied. The first derivatives enter as an implicit operator for yielding new iterates and the second derivatives indicates smoothness of the flows considered. Consequently flows involving shocks are expected to require larger number of iterations. First-order upwind discretization in conjunction with the Steger-Warming flux-vector splitting is employed on the implicit operator and a diagonal dominant matrix results. However the explicit operator is represented by first- and seond-order upwind differencings, using both Steger-Warming's and van Leer's splittings. We discuss treatment of boundary conditions and solution procedures for solving the resulting block matrix system. With a set of test problems for one- and two-dimensional flows, we show detailed study as to the efficiency, accuracy, and convergence of the present method.

Formation of DNA adducts by ellipticine and its micellar form in rats - a comparative study.

PubMed

Stiborova, Marie; Manhartova, Zuzana; Hodek, Petr; Adam, Vojtech; Kizek, Rene; Frei, Eva

2014-12-03

The requirements for early diagnostics as well as effective treatment of cancer diseases have increased the pressure on development of efficient methods for targeted drug delivery as well as imaging of the treatment success. One of the most recent approaches covering the drug delivery aspects is benefitting from the unique properties of nanomaterials. Ellipticine and its derivatives are efficient anticancer compounds that function through multiple mechanisms. Formation of covalent DNA adducts after ellipticine enzymatic activation is one of the most important mechanisms of its pharmacological action. In this study, we investigated whether ellipticine might be released from its micellar (encapsulated) form to generate covalent adducts analogous to those formed by free ellipticine. The (32)P-postlabeling technique was used as a useful imaging method to detect and quantify covalent ellipticine-derived DNA adducts. We compared the efficiencies of free ellipticine and its micellar form (the poly(ethylene oxide)-block-poly(allyl glycidyl ether) (PAGE-PEO) block copolymer, P 119 nanoparticles) to form ellipticine-DNA adducts in rats in vivo. Here, we demonstrate for the first time that treatment of rats with ellipticine in micelles resulted in formation of ellipticine-derived DNA adducts in vivo and suggest that a gradual release of ellipticine from its micellar form might produce the enhanced permeation and retention effect of this ellipticine-micellar delivery system.

Effect of calf death loss on cloned cattle herd derived from somatic cell nuclear transfer: clones with congenital defects would be removed by the death loss.

PubMed

Watanabe, Shinya

2013-09-01

To increase public understanding on cloned cattle derived from somatic cell nuclear transfer (SCNT), the present review describes the effect of calf death loss on an SCNT cattle herd. The incidence of death loss in SCNT cattle surviving more than 200 days reached the same level as that in conventionally bred cattle. This process could be considered as removal of SCNT cattle with congenital defects caused by calf death loss. As a result of comparative studies of SCNT cattle and conventionally bred cattle, the substantial equivalences in animal health status, milk and meat productive performance have been confirmed. Both sexes of SCNT cattle surviving to adulthood were fertile and their reproductive performance, including efficiency of progeny production, was the same as that in conventionally bred cattle. The presence of substantial equivalence between their progeny and conventionally bred cattle also existed. Despite these scientific findings, the commercial use of food products derived from SCNT cattle and their progeny has not been allowed by governments for reasons including the lack of public acceptance of these products and the low efficiency of animal SCNT. To overcome this situation, communication of the low risk of SCNT technology and research to improve SCNT efficiency are required. © 2013 Japanese Society of Animal Science.

A polymeric prodrug of 5-fluorouracil-1-acetic acid using a multi-hydroxyl polyethylene glycol derivative as the drug carrier.

PubMed

Li, Man; Liang, Zhen; Sun, Xun; Gong, Tao; Zhang, Zhirong

2014-01-01

Macromolecular prodrugs obtained by covalently conjugating small molecular drugs with polymeric carriers were proven to accomplish controlled and sustained release of the therapeutic agents in vitro and in vivo. Polyethylene glycol (PEG) has been extensively used due to its low toxicity, low immunogenicity and high biocompatibility. However, for linear PEG macromolecules, the number of available hydroxyl groups for drug coupling does not change with the length of polymeric chain, which limits the application of PEG for drug conjugation purposes. To increase the drug loading and prolong the retention time of 5-fluorouracil (5-Fu), a macromolecular prodrug of 5-Fu, 5-fluorouracil-1 acid-PAE derivative (5-FA-PAE) was synthesized and tested for the antitumor activity in vivo. PEG with a molecular weight of 38 kDa was selected to synthesize the multi-hydroxyl polyethylene glycol derivative (PAE) through an addition reaction. 5-fluorouracil-1 acetic acid (5-FA), a 5-Fu derivative was coupled with PEG derivatives via ester bond to form a macromolecular prodrug, 5-FA-PAE. The in vitro drug release, pharmacokinetics, in vivo distribution and antitumor effect of the prodrug were investigated, respectively. The PEG-based prodrug obtained in this study possessed an exceedingly high 5-FA loading efficiency of 10.58%, much higher than the maximum drug loading efficiency of unmodified PEG with the same molecular weight, which was 0.98% theoretically. Furthermore, 5-FA-PAE exhibited suitable sustained release in tumors. This study provides a new approach for the development of the delivery to tumors of anticancer agents with PEG derivatives.

Enhancement of mercury capture by the simultaneous addition of hydrogen bromide (HBr) and fly ashes in a slipstream facility

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

Yan Cao; Quan-Hai Wang; Jun Li

2009-04-15

Low halogen content in tested Powder River Basin (PRB) coals and low loss of ignition content (LOI) in PRB-derived fly ash were likely responsible for higher elemental mercury content (averaging about 75%) in the flue gas and also lower mercury capture efficiency by electrostatic precipitator (ESP) and wet-FGD. To develop a cost-effective approach to mercury capture in a full-scale coal-fired utility boiler burning PRB coal, experiments were conducted adding hydrogen bromide (HBr) or simultaneously adding HBr and selected fly ashes in a slipstream reactor (0.152 x 0.152 m) under real flue gas conditions. The residence time of the flue gasmore » inside the reactor was about 1.4 s. The average temperature of the slipstream reactor was controlled at about 155{sup o}C. Tests were organized into two phases. In Phase 1, only HBr was added to the slipstream reactor, and in Phase 2, HBr and selected fly ash were added simultaneously. HBr injection was effective (>90%) for mercury oxidation at a low temperature (155{sup o}C) with an HBr addition concentration of about 4 ppm in the flue gas. Additionally, injected HBr enhanced mercury capture by PRB fly ash in the low-temperature range. The mercury capture efficiency, at testing conditions of the slipstream reactor, reached about 50% at an HBr injection concentration of 4 ppm in the flue gas. Compared to only the addition of HBr, simultaneously adding bituminous-derived fly ash in a minimum amount (30 lb/MMacf), together with HBr injection at 4 ppm, could increase mercury capture efficiency by 30%. Injection of lignite-derived fly ash at 30 lb/MMacf could achieve even higher mercury removal efficiency (an additional 35% mercury capture efficiency compared to HBR addition alone). 25 refs., 5 figs., 1 tab.« less

Green synthesis of chalcones derivatives as intermediate of flavones and their antibacterial activities

NASA Astrophysics Data System (ADS)

VH, Elfi Susanti; Matsjeh, Sabirin; Wahyuningsih, Tutik Dwi; Mustofa, Redjeki, Tri

2016-02-01

Four chalcones derivatives have been synthesized from 3,4-dimethoxybenzaldehyde and acetophenone derivatives (2-hydroxy acetophenone, 2,4-dihydroxy acetophenone, 2,5-dihydroxy acetophenone and 2,6-dihydroxy acetophenone). The synthesis of these chalcones were conducted by Claisen-Schmidt condensation using grinding techniques at room temperature in the absence of solvents. The chalcones were prepared by grinding together equivalent amount of the approriate hydroxyacetophenone and 3,4-dimethoxybenzaldehyde in the presence of solid sodium hydroxide. Grinding techniques for synthesis of the chalcones derivatives is simple, efficient and environmentally benign compared to conventional methods. Then, the four chalcones derivatives undergo cyclization reactions to produce four flavones after reacted with iodine. The synthesized compounds were characterized by spectrometry (IR, 1H-NMR, 13C-NMR and MS).

Metabolic engineering of Saccharomyces cerevisiae for production of fatty acid-derived hydrocarbons.

PubMed

Zhang, Yiming; Nielsen, Jens; Liu, Zihe

2018-06-05

Fatty acid-derived hydrocarbons attract increasing attention as biofuels due to their immiscibility with water, high-energy content, low freezing point, and high compatibility with existing refineries and end-user infrastructures. Yeast Saccharomyces cerevisiae has advantages for production of fatty acid-derived hydrocarbons as its native routes toward fatty acid synthesis involve only a few reactions that allow more efficient conversion of carbon substrates. Here we describe major biosynthetic pathways of fatty acid-derived hydrocarbons in yeast, and summarize key metabolic engineering strategies, including enhancing precursor supply, eliminating competing pathways, and expressing heterologous pathways. With recent advances in yeast production of fatty acid-derived hydrocarbons, our review identifies key research challenges and opportunities for future optimization, and concludes with perspectives and outlooks for further research directions. © 2018 Wiley Periodicals, Inc.

Combustion studies of coal derived solid fuels by thermogravimetric analysis. III. Correlation between burnout temperature and carbon combustion efficiency

USGS Publications Warehouse

Rostam-Abadi, M.; DeBarr, J.A.; Chen, W.T.

1990-01-01

Burning profiles of 35-53 ??m size fractions of an Illinois coal and three partially devolatilized coals prepared from the original coal were obtained using a thermogravimetric analyzer. The burning profile burnout temperatures were higher for lower volatile fuels and correlated well with carbon combustion efficiencies of the fuels when burned in a laboratory-scale laminar flow reactor. Fuels with higher burnout temperatures had lower carbon combustion efficiencies under various time-temperature conditions in the laboratory-scale reactor. ?? 1990.

Data compression for satellite images

NASA Technical Reports Server (NTRS)

Chen, P. H.; Wintz, P. A.

1976-01-01

An efficient data compression system is presented for satellite pictures and two grey level pictures derived from satellite pictures. The compression techniques take advantages of the correlation between adjacent picture elements. Several source coding methods are investigated. Double delta coding is presented and shown to be the most efficient. Both predictive differential quantizing technique and double delta coding can be significantly improved by applying a background skipping technique. An extension code is constructed. This code requires very little storage space and operates efficiently. Simulation results are presented for various coding schemes and source codes.

How noise affects quantum detector tomography

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

Wang, Q., E-mail: wang@physics.leidenuniv.nl; Renema, J. J.; Exter, M. P.van

2015-10-07

We determine the full photon number response of a NbN superconducting nanowire single photon detector via quantum detector tomography, and the results show the separation of linear, effective absorption efficiency from the internal detection efficiencies. In addition, we demonstrate an error budget for the complete quantum characterization of the detector. We find that for short times, the dominant noise source is shot noise, while laser power fluctuations limit the accuracy for longer timescales. The combined standard uncertainty of the internal detection efficiency derived from our measurements is about 2%.

Synthesis of High-Load, Hybrid Silica-Immobilized Heterocyclic Benzyl Phosphate (Si–OHBP) and Triazolyl Phosphate (Si–OHTP) Alkylating Reagents

PubMed Central

2016-01-01

The development of new ROMP-derived silica-immobilized heterocyclic phosphate reagents and their application in purification-free protocols is reported. Grafting of norbornenyl norbornenyl-functionalized (Nb-tagged) silica particles with functionalized Nb-tagged heterocyclic phosphate monomers efficiently yield high-load, hybrid silica-immobilized oligomeric heterobenzyl phosphates (Si–OHBP) and heterotriazolyl phosphates (Si–OHTP) as efficient alkylation agents. Applications of these reagents for the diversification of N-, O-, and S-nucleophilic species, for efficient heterobenzylation and hetero(triazolyl)methylation have been validated. PMID:27300761

Reductive Bis-addition of Aromatic Aldehydes to α,β-Unsaturated Esters via the Use of Sm/Cu(I) in Air: A Route to the Construction of Furofuran Lignans.

PubMed

Liu, Yongjun; Tian, Guang; Li, Jingjing; Qi, Yan; Wen, Yonghong; Du, Feng

2017-06-02

The novel bis-addition of benzaldehydes to acrylates or maleates was achieved by the direct use of samarium metal with the assistance of CuI under mild conditions under dry air, and the useful 2-hydroxylalkyl-γ-butyrolactons and lignan derivatives were thus constructed with high efficiency. The key factors that influence the reaction efficiency were investigated. The use of potassium iodide and molecular sieves as additives can improve the reaction efficiency remarkably.

2D constant-loss taper for mode conversion

NASA Astrophysics Data System (ADS)

Horth, Alexandre; Kashyap, Raman; Quitoriano, Nathaniel J.

2015-03-01

Proposed in this manuscript is a novel taper geometry, the constant-loss taper (CLT). This geometry is derived with 1D slabs of silicon embedded in silicon dioxide using coupled-mode theory (CMT). The efficiency of the CLT is compared to both linear and parabolic tapers using CMT and 2D finite-difference time-domain simulations. It is shown that over a short 2D, 4.45 μm long taper the CLT's mode conversion efficiency is ~90% which is 10% and 18% more efficient than a 2D parabolic or linear taper, respectively.

Basal area increment and growth efficiency as functions of canopy dynamics and stem mechanics

Treesearch

Thomas J. Dean

2004-01-01

Crown and canopy structurecorrelate with growth efficiency and also determine stem size and taper as described by the uniform stress principle of stem formation. A regression model was derived from this principle that expresses basal area increment in terms of the amount and vertical distribution of leaf area and change in these variables during a growth period. This...

Enhanced ambient stability of efficient perovskite solar cells by employing a modified fullerene cathode interlayer

DOE PAGES

Zhu, Zonglong; Chueh, Chu -Chen; Lin, Francis; ...

2016-03-22

A novel fullerene cathode interlayer is employed to facilitate the fabrication of stable and efficient perovskite solar cells. Here, this modified fullerene surfactant significantly increases air stability of the derived devices due to its hydrophobic characteristics to enable 80% of the initial PCE to be retained after being exposed in ambient condition with 20% relative humidity for 14 days.

ESCDL-1, a new cell line derived from chicken embryonic stem cells, supports efficient replication of Mardiviruses

PubMed Central

Jean, Christian; Fragnet-Trapp, Laetitia; Rémy, Sylvie; Chabanne-Vautherot, Danièle; Montillet, Guillaume; Fuet, Aurélie; Denesvre, Caroline; Pain, Bertrand

2017-01-01

Marek’s disease virus is the etiological agent of a major lymphoproliferative disorder in poultry and the prototype of the Mardivirus genus. Primary avian somatic cells are currently used for virus replication and vaccine production, but they are largely refractory to any genetic modification compatible with the preservation of intact viral susceptibility. We explored the concept of induction of viral replication permissiveness in an established pluripotent chicken embryonic stem cell-line (cES) in order to derive a new fully susceptible cell-line. Chicken ES cells were not permissive for Mardivirus infection, but as soon as differentiation was triggered, replication of Marek’s disease virus was detected. From a panel of cyto-differentiating agents, hexamethylene bis (acetamide) (HMBA) was found to be the most efficient regarding the induction of permissiveness. These initial findings prompted us to analyse the effect of HMBA on gene expression, to derive a new mesenchymal cell line, the so-called ESCDL-1, and monitor its susceptibility for Mardivirus replication. All Mardiviruses tested so far replicated equally well on primary embryonic skin cells and on ESCDL-1, and the latter showed no variation related to its passage number in its permissiveness for virus infection. Viral morphogenesis studies confirmed efficient multiplication with, as in other in vitro models, no extra-cellular virus production. We could show that ESCDL-1 can be transfected to express a transgene and subsequently cloned without any loss in permissiveness. Consequently, ESCDL-1 was genetically modified to complement viral gene deletions thus yielding stable trans-complementing cell lines. We herein claim that derivation of stable differentiated cell-lines from cES cell lines might be an alternative solution to the cultivation of primary cells for virology studies. PMID:28406989

Generation of Functional Human Hepatic Endoderm from Human iPS cells

PubMed Central

Sullivan, Gareth J.; Hay, David C.; Park, In-Hyun; Fletcher, Judy; Hannoun, Zara; Payne, Catherine M.; Dalgetty, Donna; Black, James R.; Ross, James A.; Samuel, Kay; Wang, Gang; Daley, George Q.; Lee, Je-Hyuk; Church, George M.; Forbes, Stuart J.; Iredale, John P.; Wilmut, Ian

2009-01-01

With the advent of induced pluripotent stem cell (iPSC) technology, it is now feasible to generate iPSCs with a defined genotype or disease state. When coupled with direct differentiation of defined lineage, such as hepatic endoderm (HE). iPSC would revolutionise the way we study human liver biology and generate efficient “off the shelf” models of human liver disease. Here we show the `proof of concept' that iPSC lines representing both male and female sexes and two ethnic origins can be differentiated to HE at efficiencies of between 70–90%, using a method mimicking a physiological condition. iPSC-derived HE exhibited hepatic morphology, and expressed the hepatic markers, Albumin and E-Cadherin as assessed by immuno-histochemistry. They also expressed alpha fetal protein (AFP), HNF4a, and a metabolic marker, Cyp7A1, demonstrating a definitive endodermal lineage differentiation. Furthermore, iPSC-derived hepatocytes produced and secreted the plasma proteins, fibrinogen, fibronectin, transthyretin (TTR) and AFP, an essential feature for functional HE. Additionally iPSC-derived HE supported both CYP1A2 and 3A4 metabolism, which is essential for drug and toxicology testing. Conclusion This work is first to demonstrate the efficient generation of hepatic endodermal lineage from human iPSC that exhibits key attributes of hepatocytes, and the potential application of iPSC-derived HE in studying human liver biology. In particular, iPSC from individuals representing highly polymorphic variants in metabolic genes and different ethnic groups will provide pharmaceutical development and toxicology studies a unique opportunity to revolutionise predictive drug toxicology assays and allow the creation of in vitro hepatic disease models. PMID:19877180

PiggyBac transposon-mediated gene delivery efficiently generates stable transfectants derived from cultured primary human deciduous tooth dental pulp cells (HDDPCs) and HDDPC-derived iPS cells.

PubMed

Inada, Emi; Saitoh, Issei; Watanabe, Satoshi; Aoki, Reiji; Miura, Hiromi; Ohtsuka, Masato; Murakami, Tomoya; Sawami, Tadashi; Yamasaki, Youichi; Sato, Masahiro

2015-09-14

The ability of human deciduous tooth dental pulp cells (HDDPCs) to differentiate into odontoblasts that generate mineralized tissue holds immense potential for therapeutic use in the field of tooth regenerative medicine. Realization of this potential depends on efficient and optimized protocols for the genetic manipulation of HDDPCs. In this study, we demonstrate the use of a PiggyBac (PB)-based gene transfer system as a method for introducing nonviral transposon DNA into HDDPCs and HDDPC-derived inducible pluripotent stem cells. The transfection efficiency of the PB-based system was significantly greater than previously reported for electroporation-based transfection of plasmid DNA. Using the neomycin resistance gene as a selection marker, HDDPCs were stably transfected at a rate nearly 40-fold higher than that achieved using conventional methods. Using this system, it was also possible to introduce two constructs simultaneously into a single cell. The resulting stable transfectants, expressing tdTomato and enhanced green fluorescent protein, exhibited both red and green fluorescence. The established cell line did not lose the acquired phenotype over three months of culture. Based on our results, we concluded that PB is superior to currently available methods for introducing plasmid DNA into HDDPCs. There may be significant challenges in the direct clinical application of this method for human dental tissue engineering due to safety risks and ethical concerns. However, the high level of transfection achieved with PB may have significant advantages in basic scientific research for dental tissue engineering applications, such as functional studies of genes and proteins. Furthermore, it is a useful tool for the isolation of genetically engineered HDDPC-derived stem cells for studies in tooth regenerative medicine.

Oxygen and iron production by electrolytic smelting of lunar soil

NASA Technical Reports Server (NTRS)

Haskin, Larry A.

1989-01-01

Previous work has shown that Fe(sup 0) and O2 can be derived by electrolysis from silicate smelt of a composition typical of lunar soils (Lindstrom and Haskin 1979). In the present study, the goal is to refine further the conditions necessary to optimize production and to determine efficiencies of production (how much product is derived for a given current) and purity of products. These depend on several factors, including potential imposed between electrodes, configuration and surface area of the electrodes, composition of the electrolyzed silicate melt, and oxygen fugacity. Experiments were designed to measure the dependence on these variables of three parameters that must be known before production by electrolysis can be optimized. These parameters are: Limiting Current; Actual Current; and Efficiencies of Production.

Efficient scheme for parametric fitting of data in arbitrary dimensions.

PubMed

Pang, Ning-Ning; Tzeng, Wen-Jer; Kao, Hisen-Ching

2008-07-01

We propose an efficient scheme for parametric fitting expressed in terms of the Legendre polynomials. For continuous systems, our scheme is exact and the derived explicit expression is very helpful for further analytical studies. For discrete systems, our scheme is almost as accurate as the method of singular value decomposition. Through a few numerical examples, we show that our algorithm costs much less CPU time and memory space than the method of singular value decomposition. Thus, our algorithm is very suitable for a large amount of data fitting. In addition, the proposed scheme can also be used to extract the global structure of fluctuating systems. We then derive the exact relation between the correlation function and the detrended variance function of fluctuating systems in arbitrary dimensions and give a general scaling analysis.

Determination of Aniline and Its Derivatives in Environmental Water by Capillary Electrophoresis with On-Line Concentration

PubMed Central

Liu, Shuhui; Wang, Wenjun; Chen, Jie; Sun, Jianzhi

2012-01-01

This paper describes a simple, sensitive and environmentally benign method for the direct determination of aniline and its derivatives in environmental water samples by capillary zone electrophoresis (CZE) with field-enhanced sample injection. The parameters that influenced the enhancement and separation efficiencies were investigated. Surprisingly, under the optimized conditions, two linear ranges for the calibration plot, 1–50 ng/mL and 50–1000 ng/mL (R > 0.998), were obtained. The detection limit was in the range of 0.29–0.43 ng/mL. To eliminate the effect of the real sample matrix on the stacking efficiency, the standard addition method was applied to the analysis of water samples from local rivers. PMID:22837668

Enabling technologies and green processes in cyclodextrin chemistry

PubMed Central

Caporaso, Marina; Jicsinszky, Laszlo; Martina, Katia

2016-01-01

Summary The design of efficient synthetic green strategies for the selective modification of cyclodextrins (CDs) is still a challenging task. Outstanding results have been achieved in recent years by means of so-called enabling technologies, such as microwaves, ultrasound and ball mills, that have become irreplaceable tools in the synthesis of CD derivatives. Several examples of sonochemical selective modification of native α-, β- and γ-CDs have been reported including heterogeneous phase Pd- and Cu-catalysed hydrogenations and couplings. Microwave irradiation has emerged as the technique of choice for the production of highly substituted CD derivatives, CD grafted materials and polymers. Mechanochemical methods have successfully furnished greener, solvent-free syntheses and efficient complexation, while flow microreactors may well improve the repeatability and optimization of critical synthetic protocols. PMID:26977187

Delaunay-based derivative-free optimization for efficient minimization of time-averaged statistics of turbulent flows

NASA Astrophysics Data System (ADS)

Beyhaghi, Pooriya

2016-11-01

This work considers the problem of the efficient minimization of the infinite time average of a stationary ergodic process in the space of a handful of independent parameters which affect it. Problems of this class, derived from physical or numerical experiments which are sometimes expensive to perform, are ubiquitous in turbulence research. In such problems, any given function evaluation, determined with finite sampling, is associated with a quantifiable amount of uncertainty, which may be reduced via additional sampling. This work proposes the first algorithm of this type. Our algorithm remarkably reduces the overall cost of the optimization process for problems of this class. Further, under certain well-defined conditions, rigorous proof of convergence is established to the global minimum of the problem considered.

Baculovirus: an Insect-derived Vector for Diverse Gene Transfer Applications

PubMed Central

Airenne, Kari J; Hu, Yu-Chen; Kost, Thomas A; Smith, Richard H; Kotin, Robert M; Ono, Chikako; Matsuura, Yoshiharu; Wang, Shu; Ylä-Herttuala, Seppo

2013-01-01

Insect-derived baculoviruses have emerged as versatile and safe workhorses of biotechnology. Baculovirus expression vectors (BEVs) have been applied widely for crop and forest protection, as well as safe tools for recombinant protein production in insect cells. However, BEVs ability to efficiently transduce noninsect cells is still relatively poorly recognized despite the fact that efficient baculovirus-mediated in vitro and ex vivo gene delivery into dormant and dividing vertebrate cells of diverse origin has been described convincingly by many authors. Preliminary proof of therapeutic potential has also been established in preclinical studies. This review summarizes the advantages and current status of baculovirus-mediated gene delivery. Stem cell transduction, preclinical animal studies, tissue engineering, vaccination, cancer gene therapy, viral vector production, and drug discovery are covered. PMID:23439502

An efficient approach for surveillance of childhood diabetes by type derived from electronic health record data: the SEARCH for Diabetes in Youth Study

PubMed Central

Zhong, Victor W; Obeid, Jihad S; Craig, Jean B; Pfaff, Emily R; Thomas, Joan; Jaacks, Lindsay M; Beavers, Daniel P; Carey, Timothy S; Lawrence, Jean M; Dabelea, Dana; Hamman, Richard F; Bowlby, Deborah A; Pihoker, Catherine; Saydah, Sharon H

2016-01-01

Objective To develop an efficient surveillance approach for childhood diabetes by type across 2 large US health care systems, using phenotyping algorithms derived from electronic health record (EHR) data. Materials and Methods Presumptive diabetes cases <20 years of age from 2 large independent health care systems were identified as those having ≥1 of the 5 indicators in the past 3.5 years, including elevated HbA1c, elevated blood glucose, diabetes-related billing codes, patient problem list, and outpatient anti-diabetic medications. EHRs of all the presumptive cases were manually reviewed, and true diabetes status and diabetes type were determined. Algorithms for identifying diabetes cases overall and classifying diabetes type were either prespecified or derived from classification and regression tree analysis. Surveillance approach was developed based on the best algorithms identified. Results We developed a stepwise surveillance approach using billing code–based prespecified algorithms and targeted manual EHR review, which efficiently and accurately ascertained and classified diabetes cases by type, in both health care systems. The sensitivity and positive predictive values in both systems were approximately ≥90% for ascertaining diabetes cases overall and classifying cases with type 1 or type 2 diabetes. About 80% of the cases with “other” type were also correctly classified. This stepwise surveillance approach resulted in a >70% reduction in the number of cases requiring manual validation compared to traditional surveillance methods. Conclusion EHR data may be used to establish an efficient approach for large-scale surveillance for childhood diabetes by type, although some manual effort is still needed. PMID:27107449

An objective frequency domain method for subsurface characterisation using Earth and atmospheric tides

NASA Astrophysics Data System (ADS)

Cuthbert, M. O.; Acworth, I. R.; Halloran, L. J. S.; Rau, G. C.; Bernadi, T. L.

2017-12-01

It has long been recognised that hydraulic properties can be derived from the response of piezometric heads to tidal loadings. However, there is a degree of subjectivity in existing graphical approaches most commonly used to calculate barometric efficiency leading to uncertainties in derived values of compressible storage. Here we demonstrate a novel approach to remove these uncertainties by objectively deriving the barometric efficiency from groundwater hydraulic head responses using a frequency domain method. We take advantage of the presence of worldwide and ubiquitous atmospheric tide fluctuations which occur at 2 cycles per day (cpd). First we use a Fourier transform to calculate the amplitudes of the 2 cpd signals from co-located atmospheric pressure and hydraulic head time series measurements. Next we show how the Earth tide response at the same frequency can be quantified and removed so that this effect does not interfere with the calculation of the barometric efficiency. Finally, the ratio of the amplitude of the response at 2 cpd of hydraulic head to atmospheric pressure is used to quantify the barometric efficiency. This new method allows an objective quantification using `passive' in situ monitoring rather than resorting to aquifer pumping or laboratory tests. The minimum data requirements are 15 days duration of 6-hourly hydraulic head and atmospheric pressure measurements, and modelled Earth tide records which are readily conducted using freely available software. The new approach allows for a rapid and cost-effective alternative to traditional methods of estimating aquifer compressible storage properties without the subjectivity of existing approaches, and will be of importance to improving the spatial coverage of subsurface characterisation for groundwater resource evaluation and land subsidence assessment.

Application of calculated NMR parameters, aromaticity indices and wavefunction properties for evaluation of corrosion inhibition efficiency of pyrazine inhibitors

NASA Astrophysics Data System (ADS)

Behzadi, Hadi; Manzetti, Sergio; Dargahi, Maryam; Roonasi, Payman; Khalilnia, Zahra

2018-01-01

In light of the importance of developing novel corrosion inhibitors, a series of quantum chemical calculations were carried out to evaluate 15N chemical shielding CS tensors as well as aromaticity indexes including NICS, HOMA, FLU, and PDI of three pyrazine derivatives, 2-methylpyrazine (MP), 2-aminopyrazine (AP) and 2-amino-5-bromopyrazine (ABP). The NICS parameters have been shown in previous studies to be paramount to the prediction of anti-corrosion properties, and have been combined here with HOMA, FLU and PDI and detailed wavefunction analysis to determine the effects from bromination and methylation on pyrazine. The results show that the electron density around the nitrogens, represented by CS tensors, can be good indicators of anti-corrosion efficiency. Additionally, the NICS, FLU and PDI, as aromaticity indicators of molecule, are well correlated with experimental corrosion inhibition efficiencies of the studied inhibitors. Bader sampling and detailed wavefunction analysis shows that the major effects from bromination on the pyrazine derivatives affect the Laplacian of the electron density of the ring, delocalizing the aromatic electrons of the carbon atoms into lone pairs and increasing polarization of the Laplacian values. This feature is well agreement with empirical studies, which show that ABP is the most efficient anti-corrosion compound followed by AP and MP, a property which can be attributed and predicted by derivation of the Laplacian of the electron density of the ring nuclei. This study shows the importance of devising DFT methods for development of new corrosion inhibitors, and the strength of electronic and nuclear analysis, and depicts most importantly how corrosion inhibitors composed of aromatic moieties may be modified to increase anti-corrosive properties.

Enzyme efficiency: An open reaction system perspective

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

Banerjee, Kinshuk, E-mail: kb36@rice.edu; Bhattacharyya, Kamal, E-mail: pchemkb@gmail.com

2015-12-21

A measure of enzyme efficiency is proposed for an open reaction network that, in suitable form, applies to closed systems as well. The idea originates from the description of classical enzyme kinetics in terms of cycles. We derive analytical expressions for the efficiency measure by treating the network not only deterministically but also stochastically. The latter accounts for any significant amount of noise that can be present in biological systems and hence reveals its impact on efficiency. Numerical verification of the results is also performed. It is found that the deterministic equation overestimates the efficiency, the more so for verymore » small system sizes. Roles of various kinetics parameters and system sizes on the efficiency are thoroughly explored and compared with the standard definition k{sub 2}/K{sub M}. Study of substrate fluctuation also indicates an interesting efficiency-accuracy balance.« less

GSH- and pH-responsive drug delivery system constructed by water-soluble pillar[5]arene and lysine derivative for controllable drug release.

PubMed

Wu, Xuan; Li, Yan; Lin, Chen; Hu, Xiao-Yu; Wang, Leyong

2015-04-21

Novel GSH- and pH-responsive supramolecular vesicles constructed by an amphiphilic inclusion complex formed from water-soluble pillar[5]arene and lysine derivative have been successfully developed, which can efficiently encapsulate anticancer drug MTZ and show rapid MTZ-release in a simulated acidic tumor environment with high GSH concentration, and exhibit potent antitumor activity.

Cyclopentanone Derivatives from 5-Hydroxymethylfurfural via 1-Hydroxyhexane-2,5-dione as Intermediate.

PubMed

Wozniak, Bartosz; Spannenberg, Anke; Li, Yuehui; Hinze, Sandra; de Vries, Johannes G

2018-01-23

An efficient strategy for the conversion of biomass derived 5-hydroxymethylfurfural (HMF) into 2-hydroxy-3-methylcyclopent-2-enone (MCP) by an intramolecular aldol condensation of 1-hydroxyhexane-2,5-dione (HHD) has been developed. Further transformations of MCP towards the diol, enol acetate, levulinic acid and N-heterocyclic compounds are also reported. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gas chromatographic determination of 1.8-naphthalimide, N-hydroxy-1.8- naphthalimide (N,N-naphthaloylhydroxylamine) and the sodium salt of N-hydroxy-1.8-naphthalimide

Treesearch

Eckhard Melcher; Frederick Green

2003-01-01

A number of naphthalimide (NI) derivatives are used as efficient laser dyes, in medicine or in transmission electron microscopy. Only N,N- naphthaloylhydroxylamine (NHA) has been shown to be an effective wood preservative against wood decay fungi and termite damage. However, limited information is available concerning the analytical detection of Nl-derivatives in...

Synthesis of organosilicon derivatives of [1]benzothieno[3,2-b][1]-benzothiophene for efficient monolayer Langmuir-Blodgett organic field effect transistors.

PubMed

Borshchev, O V; Sizov, A S; Agina, E V; Bessonov, A A; Ponomarenko, S A

2017-01-16

For the first time, the synthesis of organosilicon derivatives of dialkyl[1]benzothieno[3,2-b][1]-benzothiophene (BTBT) capable of forming a semiconducting monolayer at the water-air interface is reported. Self-assembled monolayer organic field-effect transistors prepared from these materials using the Langmuir-Blodgett technique showed high hole mobilities and excellent air stability.

A Formal Model of Ambiguity and its Applications in Machine Translation

DTIC Science & Technology

2010-01-01

structure indicates linguisti- cally implausible segmentation that might be generated using dictionary - driven approaches...derivation. As was done in the monolingual case, the functions LHS, RHSi, RHSo and υ can be extended to a derivation δ. D(q) where q ∈V denotes the... monolingual parses. My algorithm runs more efficiently than O(n6) with many grammars (including those that required using heuristic search with other parsers

Hemin-Graphene Derivatives with Increased Peroxidase Activities Restrain Protein Tyrosine Nitration.

PubMed

Xu, Huan; Yang, Zhen; Li, Hailing; Gao, Zhonghong

2017-12-14

Protein tyrosine nitration is implicated in the occurrence and progression of pathological conditions involving free radical reactions. It is well recognized that hemin can catalyze protein tyrosine nitration in the presence of nitrite and hydrogen peroxide. Generally, the catalytic efficiency is positively correlated to its peroxidase activity. In this study, however, it is found that the efficiency of hemin in catalyzing protein tyrosine nitration is largely suppressed after functionalization with graphene derivatives, even though its peroxidase-like activity is more than quadrupled. Further studies show that the oxidation of tyrosine is still observed for these composites; dityrosine formation, however, is greatly inhibited. Furthermore, these composites also exhibit strong effects on the oxidation of nitrite into nitrate. Therefore, we propose a mechanism in which hemin-graphene derivatives facilitate the oxidation of tyrosine and nitrite to produce tyrosyl radicals and nitrogen dioxide radicals in the presence of hydrogen peroxide, but graphene interlayers serve as barriers that hinder radical-radical coupling reactions; consequently, protein tyrosine nitration is restrained. This property of hemin-graphene derivatives, by which they catalyze substrate oxidation but suppress radical-radical coupling reactions, shows their great potential in selective oxidation procedures for byproduct removal. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Embryonic rather than extraembryonic tissues have more impact on the development of placental hyperplasia in cloned mice.

PubMed

Miki, H; Wakisaka, N; Inoue, K; Ogonuki, N; Mori, M; Kim, J-M; Ohta, A; Ogura, A

2009-06-01

Somatic cell cloning by nuclear transfer (NT) in mice is associated with hyperplastic placentas at term. To dissect the effects of embryonic and extraembryonic tissues on this clone-associated phenotype, we constructed diploid (2n) fused with (<-->) tetraploid (4n) chimeras from NT- and fertilization-derived (FD) embryos. Generally, the 4n cells contributed efficiently to all the extraembryonic tissues but not to the embryo itself. Embryos constructed by 2n NT<-->4n FD aggregation developed hyperplastic placentas (0.33+/-0.22 g) with a predominant contribution by NT-derived cells. Even when the population of FD-derived cells in placentas was increased using multiple FD embryos (up to four) for aggregation, most placentas remained hyperplastic (0.36+/-0.13 g). By contrast, placentas of the reciprocal combination, 2n FD<-->4n NT, were less hyperplastic (0.15+/-0.02 g). These nearly normal-looking placentas had a large proportion of NT-derived cells. Thus, embryonic rather than extraembryonic tissues had more impact on the onset of placental hyperplasia, and that the abnormal placentation in clones occurs in a noncell-autonomous manner. These findings suggest that for improvement of cloning efficiency we should understand the mechanisms regulating placentation, especially those of embryonic origin that might control the proliferation of trophoblastic lineage cells.

Prospects of banana waste utilization in wastewater treatment: A review.

PubMed

Ahmad, Tanweer; Danish, Mohammed

2018-01-15

This review article explores utilization of banana waste (fruit peels, pseudo-stem, trunks, and leaves) as precursor materials to produce an adsorbent, and its application against environmental pollutants such as heavy metals, dyes, organic pollutants, pesticides, and various other gaseous pollutants. In recent past, quite a good number of research articles have been published on the utilization of low-cost adsorbents derived from biomass wastes. The literature survey on banana waste derived adsorbents shown that due to the abundance of banana waste worldwide, it also considered as low-cost adsorbents with promising future application against various environmental pollutants. Furthermore, raw banana biomass can be chemically modified to prepare efficient adsorbent as per requirement; chemical surface functional group modification may enhance the multiple uses of the adsorbent with industrial standard. It was evident from a literature survey that banana waste derived adsorbents have significant removal efficiency against various pollutants. Most of the published articles on banana waste derived adsorbents have been discussed critically, and the conclusion is drawn based on the results reported. Some results with poorly performed experiments were also discussed and pointed out their lacking in reporting. Based on literature survey, the future research prospect on banana wastes has a significant impact on upcoming research strategy. Copyright © 2017 Elsevier Ltd. All rights reserved.

New fundamental parameters for attitude representation

NASA Astrophysics Data System (ADS)

Patera, Russell P.

2017-08-01

A new attitude parameter set is developed to clarify the geometry of combining finite rotations in a rotational sequence and in combining infinitesimal angular increments generated by angular rate. The resulting parameter set of six Pivot Parameters represents a rotation as a great circle arc on a unit sphere that can be located at any clocking location in the rotation plane. Two rotations are combined by linking their arcs at either of the two intersection points of the respective rotation planes. In a similar fashion, linking rotational increments produced by angular rate is used to derive the associated kinematical equations, which are linear and have no singularities. Included in this paper is the derivation of twelve Pivot Parameter elements that represent all twelve Euler Angle sequences, which enables efficient conversions between Pivot Parameters and any Euler Angle sequence. Applications of this new parameter set include the derivation of quaternions and the quaternion composition rule, as well as, the derivation of the analytical solution to time dependent coning motion. The relationships between Pivot Parameters and traditional parameter sets are included in this work. Pivot Parameters are well suited for a variety of aerospace applications due to their effective composition rule, singularity free kinematic equations, efficient conversion to and from Euler Angle sequences and clarity of their geometrical foundation.

Efficient Synthesis of Glaziovianin A Isoflavone Series from Dill and Parsley Extracts and Their in Vitro/in Vivo Antimitotic Activity.

PubMed

Semenov, Victor V; Tsyganov, Dmitry V; Semenova, Marina N; Chuprov-Netochin, Roman N; Raihstat, Mikhail M; Konyushkin, Leonid D; Volynchuk, Polina B; Marusich, Elena I; Nazarenko, Vera V; Leonov, Sergey V; Kiselyov, Alex S

2016-05-27

A concise six-step protocol for the synthesis of isoflavone glaziovianin A (GVA) and its alkoxyphenyl derivatives 9 starting with readily available plant metabolites from dill and parsley seeds was developed. The reaction sequence involved an efficient conversion of the key intermediate epoxides 7 into the respective β-ketoaldehydes 8 followed by their Cu(I)-mediated cyclization into the target series 9. The biological activity of GVA and its derivatives was evaluated using a panel of seven human cancer cell lines and an in vivo sea urchin embryo assay. Both screening platforms confirmed the antimitotic effect of the parent GVA (9cg) and its alkoxy derivatives. Structure-activity relationship studies suggested that compounds 9cd and 9cf substituted with trimethoxy- and dillapiol-derived B-rings, respectively, were less active than the parent 9cg. Of the evaluated human cancer cell lines, the A375 melanoma cell line was the most sensitive to the tested molecules. Notably, the target compounds were not cytotoxic against human peripheral blood mononuclear cells up to 10 μM concentration. Phenotypic readouts from the sea urchin assay unequivocally suggest a direct microtubule-destabilizing effect of isoflavones 9cg, 9cd, and 9cf.

A lower limit to the accretion disc radius in the low-luminosity AGNNGC 1052 derived from high-angular resolution data

NASA Astrophysics Data System (ADS)

Reb, Lennart; Fernández-Ontiveros, Juan A.; Prieto, M. Almudena; Dolag, Klaus

2018-07-01

We investigate the central sub-arcsec region of the low-luminosity active galactic nucleusNGC 1052, using a high-angular resolution data set that covers 10 orders of magnitude in frequency. This allows us to infer the continuum emission within the innermost ˜17 pc around the black hole to be of non-thermal, synchrotron origin and to set a limit to the maximum contribution of a standard accretion disc. Assuming the canonical 10 per cent mass-light conversion efficiency for the standard accretion disc, its inferred accretion power would be too low by one order of magnitude to account for the observed continuum luminosity. We thus introduce a truncated accretion disc and derive a truncation radius to mass-light conversion efficiency relation, which we use to reconcile the inferred accretion power with the continuum luminosity. As a result we find that a disc providing the necessary accretion power must be truncated at rtr ≳ 26 rg, consistent with the inner radius derived from the observations of the Fe Kα line in the X-ray spectrum of this nucleus. This is the first time to derive a limit on the truncation radius of the accretion disc from high-angular resolution data only.

A lower limit to the accretion disc radius in the low-luminosity AGN NGC 1052 derived from high-angular resolution data

NASA Astrophysics Data System (ADS)

Reb, Lennart; Fernández-Ontiveros, Juan A.; Prieto, M. Almudena; Dolag, Klaus

2018-05-01

We investigate the central sub-arcsec region of the low-luminosity active galactic nucleus NGC 1052, using a high-angular resolution dataset that covers 10 orders of magnitude in frequency. This allows us to infer the continuum emission within the innermost ˜17 pc around the black hole to be of non-thermal, synchrotron origin and to set a limit to the maximum contribution of a standard accretion disc. Assuming the canonical 10 per cent mass-light conversion efficiency for the standard accretion disc, its inferred accretion power would be too low by one order of magnitude to account for the observed continuum luminosity. We thus introduce a truncated accretion disc and derive a truncation radius to mass-light conversion efficiency relation, which we use to reconcile the inferred accretion power with the continuum luminosity. As a result we find that a truncated disc providing the necessary accretion power must be truncated at rtr ≳ 26 rg, consistent with the inner radius derived from the observations of the Fe Kα line in the X-ray spectrum of this nucleus. This is the first time to derive a limit on the truncation radius of the accretion disc from high-angular resolution data only.

Diflerent formulations of microbial respiratory losses and microbial efficiency have pronounced short and long term consequences for soil C dynamics and soil respiration

NASA Astrophysics Data System (ADS)

Ballantyne, F.; Billings, S. A.

2016-12-01

Much of the variability in projections of Earth's future C balance derives from uncertainty in how to formulate and parameterize models of biologically mediated transformations of soil organic C (SOC). Over the past decade, models of belowground decomposition have incorporated more realism, namely microbial biomass and exoenzyme pools, but it remains unclear whether microbially mediated decomposition is accurately formulated. Different models and different assumptions about how microbial efficiency, defined in terms of respiratory losses, varies with temperature exert great influence on SOC and CO2 flux projections for the future. Here, we incorporate a physiologically realistic formulation of CO2 loss from microbes, distinct from extant formulations and logically consistent with microbial C uptake and losses, into belowground dynamics and contrast its projections for SOC pools and CO2 flux from soils to those from the phenomenological formulations of efficiency in current models. We quantitatively describe how short and long term SOC dynamics are influenced by different mathematical formulations of efficiency, and that our lack of knowledge regarding loss rates from SOC and microbial biomass pools, specific respiration rate and maximum substrate uptake rate severely constrains our ability to confidently parameterize microbial SOC modules in Earth System Models. Both steady-state SOC and microbial biomass C pools, as well as transient responses to perturbations, can differ substantially depending on how microbial efficiency is derived. In particular, the discrepancy between SOC stocks for different formulations of efficiency varies from negligible to more than two orders of magnitude, depending on the relative values of respiratory versus non-respiratory losses from microbial biomass. Mass-specific respiration and proportional loss rates from soil microbes emerge as key determinants of the consequences of different formulations of efficiency for C flux in soils.

Recombinant rabbit leukemia inhibitory factor and rabbit embryonic fibroblasts support the derivation and maintenance of rabbit embryonic stem cells.

PubMed

Xue, Fei; Ma, Yinghong; Chen, Y Eugene; Zhang, Jifeng; Lin, Tzu-An; Chen, Chien-Hong; Lin, Wei-Wen; Roach, Marsha; Ju, Jyh-Cherng; Yang, Lan; Du, Fuliang; Xu, Jie

2012-08-01

The rabbit is a classical experimental animal species. A major limitation in using rabbits for biomedical research is the lack of germ-line-competent rabbit embryonic stem cells (rbESCs). We hypothesized that the use of homologous feeder cells and recombinant rabbit leukemia inhibitory factor (rbLIF) might improve the chance in deriving germ-line-competent rbES cells. In the present study, we established rabbit embryonic fibroblast (REF) feeder layers and synthesized recombinant rbLIF. We derived a total of seven putative rbESC lines, of which two lines (M5 and M23) were from culture Condition I using mouse embryonic fibroblasts (MEFs) as feeders supplemented with human LIF (hLIF) (MEF+hLIF). Another five lines (R4, R9, R15, R21, and R31) were derived from Condition II using REFs as feeder cells supplemented with rbLIF (REF+rbLIF). Similar derivation efficiency was observed between these two conditions (8.7% vs. 10.2%). In a separate experiment with 2×3 factorial design, we examined the effects of feeder cells (MEF vs. REF) and LIFs (mLIF, hLIF vs. rbLIF) on rbESC culture. Both Conditions I and II supported satisfactory rbESC culture, with similar or better population doubling time and colony-forming efficiency than other combinations of feeder cells with LIFs. Rabbit ESCs derived and maintained on both conditions displayed typical ESC characteristics, including ESC pluripotency marker expression (AP, Oct4, Sox2, Nanog, and SSEA4) and gene expression (Oct4, Sox2, Nanog, c-Myc, Klf4, and Dppa5), and the capacity to differentiate into three primary germ layers in vitro. The present work is the first attempt to establish rbESC lines using homologous feeder cells and recombinant rbLIF, by which the rbESCs were derived and maintained normally. These cell lines are unique resources and may facilitate the derivation of germ-line-competent rbESCs.

Synthesis of new simplified hemiasterlin derivatives with α,β-unsaturated carbonyl moiety.

PubMed

The, Chinh Pham; Thi, Tuyet Anh Dang; Hoang, Thi Phuong; Ngo, Quoc Anh; Doan, Duy Tien; Thi, Thu Ha Nguyen; Thi, Tham Pham; Thi, Thu Ha Vu; Jean, M; van de Weghe, P; Van, Tuyen Nguyen

2014-05-15

In this Letter, we report a convenient and efficient method for the synthesis of new simplified derivatives of hemiasterlin in which the α,α-dimethylbenzylic moiety A is replaced by α,β-unsaturated aryl groups as Michael acceptor. Most of these derivatives have a strong cytotoxic activity on three human tumor cell lines (KB, Hep-G2 and MCF7). Analogs 17b and 17f showed a high cytotoxicity against KB and Hep-G2 cancer cell lines comparable to paclitaxel and ellipticine. Copyright © 2014 Elsevier Ltd. All rights reserved.

Viscoelastic material inversion using Sierra-SD and ROL

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

Walsh, Timothy; Aquino, Wilkins; Ridzal, Denis

2014-11-01

In this report we derive frequency-domain methods for inverse characterization of the constitutive parameters of viscoelastic materials. The inverse problem is cast in a PDE-constrained optimization framework with efficient computation of gradients and Hessian vector products through matrix free operations. The abstract optimization operators for first and second derivatives are derived from first principles. Various methods from the Rapid Optimization Library (ROL) are tested on the viscoelastic inversion problem. The methods described herein are applied to compute the viscoelastic bulk and shear moduli of a foam block model, which was recently used in experimental testing for viscoelastic property characterization.

Fullerene derivative-doped zinc oxide nanofilm as the cathode of inverted polymer solar cells with low-bandgap polymer (PTB7-Th) for high performance.

PubMed

Liao, Sih-Hao; Jhuo, Hong-Jyun; Cheng, Yu-Shan; Chen, Show-An

2013-09-14

Modification of a ZnO cathode by doping it with a hydroxyl-containing derivative - giving a ZnO-C60 cathode - provides a fullerene-derivative-rich surface and enhanced electron conduction. Inverted polymer solar cells with the ZnO-C60 cathode display markedly improved power conversion efficiency compared to those with a pristine ZnO cathode, especially when the active layer includes the low-bandgap polymer PTB7-Th. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectroscopic investigation of the interaction of water-soluble azocalix[4]arenes with bovine serum albumin.

PubMed

Fan, Ping; Wan, Lu; Shang, Yunshan; Wang, Jun; Liu, Yulong; Sun, Xiaoyu; Chen, Chen

2015-02-01

In this work, three hydrosoluble azocalix[4]arene derivatives, 5-(o-methylphenylazo)-25,26,27-tris(carboxymethoxy)-28-hydroxycalix[4]arene (o-MAC-Calix), 5-(m-methylphenylazo)-25,26,27-tris(carboxymethoxy)-28-hydroxycalix[4]arene (m-MAC-Calix) and 5-(p-methylphenylazo)-25,26,27-tris(carboxymethoxy)-28-hydroxycalix[4]arene (p-MAC-Calix) were synthesized. Their structures were characterized by infrared spectrum (IR), nuclear magnetic resonance spectrum (1H NMR and 13C NMR) and mass spectrum (MS). The interactions between these compounds and bovine serum albumin (BSA) were studied by fluorescence spectroscopy, UV-vis spectrophotometry and circular dichroic spectroscopy. According to experimental results, three azocalix[4]arene derivatives can efficiently bind to BSA molecules and the o-MAC-Calix displays more efficient interactions with BSA molecules than m-MAC-Calix and p-MAC-Calix. Molecular docking showed that the o-MAC-Calix was embedded in the hydrophobic cavity of helical structure of BSA molecular and the tryptophan (Trp) residue of BSA molecular had strong interaction with o-MAC-Calix. The fluorescence quenching of BSA caused by azocalix[4]arene derivatives is attributed to the static quenching process. In addition, the synchronous fluorescence spectroscopy indicates that these azocalix[4]arene derivatives are more accessible to Trp residues of BSA molecules than the tyrosine (Tyr) residues. The circular dichroic spectroscopy further verified the binding of azocalix[4]arene derivatives and BSA. Copyright © 2014 Elsevier Inc. All rights reserved.

Autologous adipose tissue-derived stromal cells for treatment of spinal cord injury.

PubMed

Kang, Soo-Kyung; Shin, Myung-Joo; Jung, Jin Sup; Kim, Yong Geun; Kim, Cheul-Hong

2006-08-01

Isolated rat adipose tissue-derived stromal cells (rATSCs) contain pluripotent cells that can be differentiated into a variety of cell lineages, including neural cells. Recent work has shown that ATSCs can make neurosphere-like clumps and differentiate into neuron-like cells expressing neuronal markers, but their therapeutic effect is unclear. Here we report that intravenous infusion of oligodendrocyte precursor cells (OPCs) derived from rATSC autograft cells sources improve motor function in rat models of spinal cord injury (SCI). After 4-5 weeks, transplanted rATSC-OPC cells survived and migrated into the injured region of SCI very efficiently (30-35%) and migrated cells were partially differentiated into neurons and oligodendrocyte. Also, we found some of the engrafted OPCs migrated and integrated in the kidney, brain, lung, and liver through the intravenous system. Behavioral analysis revealed the locomotor functions of OPC-autografted SCI rats were significantly restored. Efficient migration of intravenously engrafted rATSC-OPCs cells into SCI lesion suggests that SCI-induced chemotaxic factors facilitate migration of rATSC-OPCs. Here, we verified that engrafted rATSCs and SCI-induced chemotaxic factors indeed play an important role in proliferation, migration, and differentiation of endogeneous spinal cord-derived neural progenitor cells in the injured region. In transplantation paradigms, the interaction between engrafted rATSC-OPCs and endogeneous spinal cord-derived neuronal progenitor cells will be important in promoting healing through fate decisions, resulting in coordinated induction of cell migration and differentiation.

Gold(III) chloride catalyzed synthesis of chiral substituted 3-formyl furans from carbohydrates: application in the synthesis of 1,5-dicarbonyl derivatives and furo[3,2-c]pyridine.

PubMed

Mal, Kanchan; Sharma, Abhinandan; Das, Indrajit

2014-09-08

This report describes a gold(III)-catalyzed efficient general route to densely substituted chiral 3-formyl furans under extremely mild conditions from suitably protected 5-(1-alkynyl)-2,3-dihydropyran-4-one using H2 O as a nucleophile. The reaction proceeds through the initial formation of an activated alkyne-gold(III) complex intermediate, followed by either a domino nucleophilic attack/anti-endo-dig cyclization, or the formation of a cyclic oxonium ion with subsequent attack by H2 O. To confirm the proposed mechanistic pathway, we employed MeOH as a nucleophile instead of H2 O to result in a substituted furo[3,2-c]pyran derivative, as anticipated. The similar furo[3,2-c]pyran skeleton with a hybrid carbohydrate-furan derivative has also been achieved through pyridinium dichromate (PDC) oxidation of a substituted chiral 3-formyl furan. The corresponding protected 5-(1-alkynyl)-2,3-dihydropyran-4-one can be synthesized from the monosaccharides (both hexoses and pentose) following oxidation, iodination, and Sonogashira coupling sequences. Furthermore, to demonstrate the potentiality of chiral 3-formyl furan derivatives, a TiBr4 -catalyzed reaction of these derivatives has been shown to offer efficient access to 1,5-dicarbonyl compounds, which on treatment with NH4 OAc in slightly acidic conditions afforded substituted furo[3,2-c]pyridine. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analytical Study on Multi-Tier 5G Heterogeneous Small Cell Networks: Coverage Performance and Energy Efficiency.

PubMed

Xiao, Zhu; Liu, Hongjing; Havyarimana, Vincent; Li, Tong; Wang, Dong

2016-11-04

In this paper, we investigate the coverage performance and energy efficiency of multi-tier heterogeneous cellular networks (HetNets) which are composed of macrocells and different types of small cells, i.e., picocells and femtocells. By virtue of stochastic geometry tools, we model the multi-tier HetNets based on a Poisson point process (PPP) and analyze the Signal to Interference Ratio (SIR) via studying the cumulative interference from pico-tier and femto-tier. We then derive the analytical expressions of coverage probabilities in order to evaluate coverage performance in different tiers and investigate how it varies with the small cells' deployment density. By taking the fairness and user experience into consideration, we propose a disjoint channel allocation scheme and derive the system channel throughput for various tiers. Further, we formulate the energy efficiency optimization problem for multi-tier HetNets in terms of throughput performance and resource allocation fairness. To solve this problem, we devise a linear programming based approach to obtain the available area of the feasible solutions. System-level simulations demonstrate that the small cells' deployment density has a significant effect on the coverage performance and energy efficiency. Simulation results also reveal that there exits an optimal small cell base station (SBS) density ratio between pico-tier and femto-tier which can be applied to maximize the energy efficiency and at the same time enhance the system performance. Our findings provide guidance for the design of multi-tier HetNets for improving the coverage performance as well as the energy efficiency.

Analytical Study on Multi-Tier 5G Heterogeneous Small Cell Networks: Coverage Performance and Energy Efficiency

PubMed Central

Xiao, Zhu; Liu, Hongjing; Havyarimana, Vincent; Li, Tong; Wang, Dong

2016-01-01

In this paper, we investigate the coverage performance and energy efficiency of multi-tier heterogeneous cellular networks (HetNets) which are composed of macrocells and different types of small cells, i.e., picocells and femtocells. By virtue of stochastic geometry tools, we model the multi-tier HetNets based on a Poisson point process (PPP) and analyze the Signal to Interference Ratio (SIR) via studying the cumulative interference from pico-tier and femto-tier. We then derive the analytical expressions of coverage probabilities in order to evaluate coverage performance in different tiers and investigate how it varies with the small cells’ deployment density. By taking the fairness and user experience into consideration, we propose a disjoint channel allocation scheme and derive the system channel throughput for various tiers. Further, we formulate the energy efficiency optimization problem for multi-tier HetNets in terms of throughput performance and resource allocation fairness. To solve this problem, we devise a linear programming based approach to obtain the available area of the feasible solutions. System-level simulations demonstrate that the small cells’ deployment density has a significant effect on the coverage performance and energy efficiency. Simulation results also reveal that there exits an optimal small cell base station (SBS) density ratio between pico-tier and femto-tier which can be applied to maximize the energy efficiency and at the same time enhance the system performance. Our findings provide guidance for the design of multi-tier HetNets for improving the coverage performance as well as the energy efficiency. PMID:27827917

Drug repurposing of novel quinoline acetohydrazide derivatives as potent COX-2 inhibitors and anti-cancer agents

NASA Astrophysics Data System (ADS)

Manohar, Chelli Sai; Manikandan, A.; Sridhar, P.; Sivakumar, A.; Siva Kumar, B.; Reddy, Sabbasani Rajasekhara

2018-02-01

Novel QuinolineAcetohydrazide (QAh) derivatives (9a-n) were firstly evaluated in silico to determine their anti-inflammatory and anti-cancer efficacy via the mechanisms of COX1 and COX2 inhibition, and NF-ĸB, HDAC and Human Topoisomerase I pathways respectively. In the studied set, the trifluoro substituted QAh derivatives: (E)-N'-(4-(trifluoro methyl) benzylidene)-2-(7-fluoro-2-methoxy quinolin-8-yl) acetohydrazid and (E)-N'-(3-(trifluoro methyl) benzylidene)-2-(7-fluoro-2-methoxy quinolin-8-yl) acetohydrazide are determined to be potential leads, indicated from their best docked scores, relative ligand efficiency, and significant structural attributes evaluated by ab initio simulations. The only setback being their partition co-efficient that retrieved a red flag in the evaluation of their Lipinski parameters. The experimental in vitro studies confirmed the significant enhancement as COX-2 inhibitors and appreciable enhancement in MTT assay of breast and skin cancer cell lines. Significantly, trifluoro substituent in the quinoline scaffold can be reasoned to note the excellent binding affinity to all the evaluated drug targets.

Application of multiwalled carbon nanotubes and its magnetite derivative for emulsified oil removal from produced water.

PubMed

Ibrahim, Taleb H; Sabri, Muhammad A; Khamis, Mustafa I

2018-05-10

Multiwalled carbon nanotubes and their magnetite derivatives were employed as adsorbents for emulsified oil removal from produced water. The experimental parameters for maximum emulsified oil removal efficiency and effective regeneration of these adsorbents were determined. The optimum parameters in terms of adsorbent dosage, contact time, salinity, pH and temperature were 3.0 g/L, 20.0 min, 0 ppm, 7.0 and 25°C for both adsorbents. Due to their low density, multiwalledcarbon nanotubes could not be successfully employed in packed bed columns. The magnetite derivative has a larger density and hence, for the removal of emulsified oil from produced water packed bed column studies were performed utilizing multiwalled carbon magnetite nanotubes. The packed bed column efficiency and behaviour were evaluated using Thomas, Clark, Yan et al. and Bohart and Adams models. The Yan model was found to best describe the column experimental data. The adsorbents were regenerated using n-hexane and reused several times for oil removal from produced water without any significant decrease in their initial adsorption capacities.

Fabrication of an Organic Light-Emitting Diode from New Host π Electron Rich Zinc Complex

NASA Astrophysics Data System (ADS)

Jafari, Mohammad Reza; Janghouri, Mohammad; Shahedi, Zahra

2017-01-01

A new π electron rich zinc complex was used as a fluorescent material in organic light-emitting diodes (OLEDs). Devices with a structure of indium tin oxide/poly (3,4-ethylenedi-oxythiophene):poly(styrenesulfonate) (PEDOT: PSS) (50 nm)/polyvinylcarbazole (60 nm)/Zn: %2 porphyrin derivatives (45 nm)/Al (150 nm) were fabricated. Porphyrin derivatives accounting for 2 wt.% in the π electron rich zinc complex were used as a host. The electroluminescence (EL) spectra of porphyrin derivatives indicated a red shift, as π electron rich zinc complex EL spectra. The device (4) has also a luminance of 3420 cd/m2 and maximum efficiency of 1.58 cd/A at 15 V, which are the highest values among four devices. The result of Commission International del'Eclairage (CIE) (X, Y) coordinate and EL spectrum of device (3) indicated that it is more red shifted compared to other devices. Results of this work indicate that π electron rich zinc complex is a promising host material for high efficiency red OLEDs and has a simple structure compared to Alq3-based devices.

Quantification of Retinogenesis in 3D Cultures Reveals Epigenetic Memory and Higher Efficiency in iPSCs Derived from Rod Photoreceptors.

PubMed

Hiler, Daniel; Chen, Xiang; Hazen, Jennifer; Kupriyanov, Sergey; Carroll, Patrick A; Qu, Chunxu; Xu, Beisi; Johnson, Dianna; Griffiths, Lyra; Frase, Sharon; Rodriguez, Alberto R; Martin, Greg; Zhang, Jiakun; Jeon, Jongrye; Fan, Yiping; Finkelstein, David; Eisenman, Robert N; Baldwin, Kristin; Dyer, Michael A

2015-07-02

Cell-based therapies to treat retinal degeneration are now being tested in clinical trials. However, it is not known whether the source of stem cells is important for the production of differentiated cells suitable for transplantation. To test this, we generated induced pluripotent stem cells (iPSCs) from murine rod photoreceptors (r-iPSCs) and scored their ability to make retinae by using a standardized quantitative protocol called STEM-RET. We discovered that r-iPSCs more efficiently produced differentiated retinae than did embryonic stem cells (ESCs) or fibroblast-derived iPSCs (f-iPSCs). Retinae derived from f-iPSCs had fewer amacrine cells and other inner nuclear layer cells. Integrated epigenetic analysis showed that DNA methylation contributes to the defects in f-iPSC retinogenesis and that rod-specific CTCF insulator protein-binding sites may promote r-iPSC retinogenesis. Together, our data suggest that the source of stem cells is important for producing retinal neurons in three-dimensional (3D) organ cultures. Copyright © 2015 Elsevier Inc. All rights reserved.

Efficient Computation of Anharmonic Force Constants via q-space, with Application to Graphene

NASA Astrophysics Data System (ADS)

Kornbluth, Mordechai; Marianetti, Chris

We present a new approach for extracting anharmonic force constants from a sparse sampling of the anharmonic dynamical tensor. We calculate the derivative of the energy with respect to q-space displacements (phonons) and strain, which guarantees the absence of supercell image errors. Central finite differences provide a well-converged quadratic error tail for each derivative, separating the contribution of each anharmonic order. These derivatives populate the anharmonic dynamical tensor in a sparse mesh that bounds the Brillouin Zone, which ensures comprehensive sampling of q-space while exploiting small-cell calculations for efficient, high-throughput computation. This produces a well-converged and precisely-defined dataset, suitable for big-data approaches. We transform this sparsely-sampled anharmonic dynamical tensor to real-space anharmonic force constants that obey full space-group symmetries by construction. Machine-learning techniques identify the range of real-space interactions. We show the entire process executed for graphene, up to and including the fifth-order anharmonic force constants. This method successfully calculates strain-based phonon renormalization in graphene, even under large strains, which solves a major shortcoming of previous potentials.

Repair of full-thickness tendon injury using connective tissue progenitors efficiently derived from human embryonic stem cells and fetal tissues.

PubMed

Cohen, Shahar; Leshansky, Lucy; Zussman, Eyal; Burman, Michael; Srouji, Samer; Livne, Erella; Abramov, Natalie; Itskovitz-Eldor, Joseph

2010-10-01

The use of stem cells for tissue engineering (TE) encourages scientists to design new platforms in the field of regenerative and reconstructive medicine. Human embryonic stem cells (hESC) have been proposed to be an important cell source for cell-based TE applications as well as an exciting tool for investigating the fundamentals of human development. Here, we describe the efficient derivation of connective tissue progenitors (CTPs) from hESC lines and fetal tissues. The CTPs were significantly expanded and induced to generate tendon tissues in vitro, with ultrastructural characteristics and biomechanical properties typical of mature tendons. We describe a simple method for engineering tendon grafts that can successfully repair injured Achilles tendons and restore the ankle joint extension movement in mice. We also show the CTP's ability to differentiate into bone, cartilage, and fat both in vitro and in vivo. This study offers evidence for the possibility of using stem cell-derived engineered grafts to replace missing tissues, and sets a basic platform for future cell-based TE applications in the fields of orthopedics and reconstructive surgery.

New serine-derived gemini surfactants as gene delivery systems.

PubMed

Cardoso, Ana M; Morais, Catarina M; Cruz, A Rita; Silva, Sandra G; do Vale, M Luísa; Marques, Eduardo F; de Lima, Maria C Pedroso; Jurado, Amália S

2015-01-01

Gemini surfactants have been extensively used for in vitro gene delivery. Amino acid-derived gemini surfactants combine the special aggregation properties characteristic of the gemini surfactants with high biocompatibility and biodegradability. In this work, novel serine-derived gemini surfactants, differing in alkyl chain lengths and in the linker group bridging the spacer to the headgroups (amine, amide and ester), were evaluated for their ability to mediate gene delivery either per se or in combination with helper lipids. Gemini surfactant-based DNA complexes were characterized in terms of hydrodynamic diameter, surface charge, stability in aqueous buffer and ability to protect DNA. Efficient formulations, able to transfect up to 50% of the cells without causing toxicity, were found at very low surfactant/DNA charge ratios (1/1-2/1). The most efficient complexes presented sizes suitable for intravenous administration and negative surface charge, a feature known to preclude potentially adverse interactions with serum components. This work brings forward a new family of gemini surfactants with great potential as gene delivery systems. Copyright © 2014 Elsevier B.V. All rights reserved.

In Vitro Antifungal Activity of Hexahydropyrimidine Derivatives against the Causative Agents of Dermatomycosis

PubMed Central

Caneschi, César A.; Senra, Mônica P.; Carvalho, Gustavo S. G.; da Silva, Adilson D.

2017-01-01

Nitrogenated heterocyclic compounds are present in both natural and synthetic drugs, and hexahydropyrimidine derivatives may prove to be efficient in treating dermatomycosis causing fungi. This study evaluated the antifungal activity of four hexahydropyrimidine derivatives against the dermatomycosis causing fungi. These derivatives were synthesized, characterized, and assessed in terms of their activity against Trichophyton mentagrophytes, Microsporum canis, Microsporum gypseum, Trichophyton rubrum, Fusarium oxysporum, and Epidermophyton floccosum between concentrations 7.8 and 1,000 μg mL−1. Scanning electron micrographs were assessed for the active derivatives and reference drugs, and these micrographs revealed that new agents cause morphological changes in fungi. The derivatives HHP1, HHP3, and HHP4 revealed poor activity against the four fungal strains (MICs range 500–1000 μg mL−1). Compound HHP3 was found to be the best potential antifungal agent among those tested and was the most effective among all the active derivatives that caused morphological changes in the susceptible strains. PMID:29226215

Experimental investigation on secondary combustion characteristics of airbreathing rockets

NASA Astrophysics Data System (ADS)

Mano, Takeshi; Eguchi, Akihiro; Shinohara, Suetsugu; Etou, Takao; Kaneko, Yutaka; Yamamoto, Youichi; Nakagawa, Ichirou

Empirical correlations of the secondary combustion efficiency of the airbreathing rocket were derived. From the results of a series of experiments employing a connected pipe facility, the combustion efficiency was related to dominant parameters. The feasibility of the performance prediction by one-dimensional analysis was also discussed. The analysis was found to be applicable to the flow processes in the secondary combustor, which include two-stream mixing and combustion.

A Systematic Method for the Condition Assessment of Central Heating Plants in Air Force Logistics Command

DTIC Science & Technology

1990-09-01

Oil Combustion/Fuel System 59 Derivation of HTHW Plant Condition Indices ...... ................. .. 65 Distribution System . ........ .. 66 HTHW...with Load ..... ............... .. 54 3. Boiler Efficiency Curve for Gas Combustion . 61 4. Boiler Efficiency Curve for Oil Combustion . 62 v List of...147 6. Round One Relative Responses for Gas and Oil Combustion/Fue System .... ............ . 147 7. Round One Relative Responses for Coal - Combustion

New method for the rapid extraction of natural products: efficient isolation of shikimic acid from star anise.

PubMed

Just, Jeremy; Deans, Bianca J; Olivier, Wesley J; Paull, Brett; Bissember, Alex C; Smith, Jason A

2015-05-15

A new, practical, rapid, and high-yielding process for the pressurized hot water extraction (PHWE) of multigram quantities of shikimic acid from star anise (Illicium verum) using an unmodified household espresso machine has been developed. This operationally simple and inexpensive method enables the efficient and straightforward isolation of shikimic acid and the facile preparation of a range of its synthetic derivatives.

Photovoltaic wire derived from a graphene composite fiber achieving an 8.45 % energy conversion efficiency.

PubMed

Yang, Zhibin; Sun, Hao; Chen, Tao; Qiu, Longbin; Luo, Yongfeng; Peng, Huisheng

2013-07-15

Wired for light: Novel wire-shaped photovoltaic devices have been developed from graphene/Pt composite fibers. The high flexibility, mechanical strength, and electrical conductivity of graphene composite fibers resulted in a maximum energy conversion efficiency of 8.45 %, which is much higher than that of other wire-shaped photovoltaic devices. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rigrod laser-pumped-laser resonator model: II. Application to thin and optically-dilute laser media

NASA Astrophysics Data System (ADS)

Brown, D. C.

2014-08-01

In part I of this paper, and to set the foundation for this part II, we derived the resonator equations describing the normalized intensities, output power, gain, and extraction efficiency for a standard resonator incorporating two dielectric mirrors and a gain element. We then generalized the results to include an absorbing region representing a second laser crystal characterized by a small-signal transmission T0. Explicit expressions were found for the output power extracted into absorption by the second laser crystal and the extraction efficiency, and the limits to each were discussed. It was shown that efficient absorption by a thin or dilute second laser crystal can be realized in resonators in which the mirror reflectivities were high and in which the single-pass absorption was low, due to the finite photon lifetime and multi-passing of the absorbing laser element. In this paper, we apply the model derived in part I to thin or dilute laser materials, concentrating on a Yb, Er:glass intracavity pumped by a 946 nm Nd:YAG laser, a Yb, Er:glass laser-pumped intracavity by a 977 nm diode laser, and an Er:YAG laser-pumped intracavity to a 1530 nm diode laser. It is shown that efficient absorption can be obtained in all cases examined.

Linking the brown and green: nutrient transformation and fate in the Sarracenia microecosystem.

PubMed

Butler, Jessica L; Gotelli, Nicholas J; Ellison, Aaron M

2008-04-01

Linkages between detritus-based ("brown") food webs and producer-based ("green") food webs are critical components of ecosystem functionality, but these linkages are hard to study because it is difficult to measure release of nutrients by brown food webs and their subsequent uptake by plants. In a three-month greenhouse experiment, we examined how the detritus-based food web inhabiting rain-filled leaves of the pitcher plant Sarracenia purpurea affects nitrogen transformation and its subsequent uptake by the plant itself. We used isotopically enriched prey (detritus) and soluble inorganic nitrogen, and manipulated food web structure to determine whether the presence of a complete brown web influences uptake efficiency of nitrogen by the plant. Uptake efficiency of soluble inorganic nitrogen was greater than that of nitrogen derived from mineralized prey. Contrary to expectation, there was no effect of the presence in the food web of macroinvertebrates on uptake efficiency of either form of nitrogen. Further, uptake efficiency of prey-derived nitrogen did not differ significantly among S. purpurea and two congeneric species (S. flava and S. alata) that lack associated food webs. Although upper trophic levels of this brown food web actively process detritus, it is the activity of the microbial component of this web that ultimately determines nitrogen availability for S. purpurea.

Significant enhancement in the power-conversion efficiency of chlorophyll co-sensitized solar cells by mimicking the principles of natural photosynthetic light-harvesting complexes.

PubMed

Wang, Xiao-Feng; Koyama, Yasushi; Kitao, Osamu; Wada, Yuji; Sasaki, Shin-Ich; Tamiaki, Hitoshi; Zhou, Haoshen

2010-04-15

Dye-sensitized solar cells (DSSCs) are similar to natural photosynthesis in the initial processes involving in light-harvesting and charge separation. In order to mimic those natural photosynthetic systems mainly containing multiple pigments, six different chlorophyllous sensitizers have been isolated from natural photosynthetic organism or synthesized based on natural photosynthetic precursors, and used for fabricating DSSCs. These dye sensitizers can be placed into three classes, i.e., a-type, b-type, or c-type, based on the structural similarity to their analogs of the natural photosynthesis pigments chlorophylls a, b, and c. We succeeded in demonstrating homogeneous co-sensitization among these analogues when these were present together on mesoporous TiO2 films, and we measured the photovoltaic performance of the resulting chlorophyll-sensitized solar cells. Significantly enhanced power-conversion efficiencies (eta) were achieved with DSSCs based on co-sensitization of a chlorophyll a derivative with a chlorophyll b or c derivative. A highest power-conversion efficiency of up to 5.4% has been obtained. These results suggest that it is possible to apply multiple pigments and the energy transfer mechanism from natural photosynthetic systems in fabricating high-efficiency DSSCs. 2010 Elsevier B.V. All rights reserved.

An exergy approach to efficiency evaluation of desalination

NASA Astrophysics Data System (ADS)

Ng, Kim Choon; Shahzad, Muhammad Wakil; Son, Hyuk Soo; Hamed, Osman A.

2017-05-01

This paper presents an evaluation process efficiency based on the consumption of primary energy for all types of practical desalination methods available hitherto. The conventional performance ratio has, thus far, been defined with respect to the consumption of derived energy, such as the electricity or steam, which are susceptible to the conversion losses of power plants and boilers that burned the input primary fuels. As derived energies are usually expressed by the units, either kWh or Joules, these units cannot differentiate the grade of energy supplied to the processes accurately. In this paper, the specific energy consumption is revisited for the efficacy of all large-scale desalination plants. In today's combined production of electricity and desalinated water, accomplished with advanced cogeneration concept, the input exergy of fuels is utilized optimally and efficiently in a temperature cascaded manner. By discerning the exergy destruction successively in the turbines and desalination processes, the relative contribution of primary energy to the processes can be accurately apportioned to the input primary energy. Although efficiency is not a law of thermodynamics, however, a common platform for expressing the figures of merit explicit to the efficacy of desalination processes can be developed meaningfully that has the thermodynamic rigor up to the ideal or thermodynamic limit of seawater desalination for all scientists and engineers to aspire to.

Thermodynamics of the mesoscopic thermoelectric heat engine beyond the linear-response regime

NASA Astrophysics Data System (ADS)

Yamamoto, Kaoru; Hatano, Naomichi

2015-10-01

Mesoscopic thermoelectric heat engine is much anticipated as a device that allows us to utilize with high efficiency wasted heat inaccessible by conventional heat engines. However, the derivation of the heat current in this engine seems to be either not general or described too briefly, even inappropriately in some cases. In this paper, we give a clear-cut derivation of the heat current of the engine with suitable assumptions beyond the linear-response regime. It resolves the confusion in the definition of the heat current in the linear-response regime. After verifying that we can construct the same formalism as that of the cyclic engine, we find the following two interesting results within the Landauer-Büttiker formalism: the efficiency of the mesoscopic thermoelectric engine reaches the Carnot efficiency if and only if the transmission probability is finite at a specific energy and zero otherwise; the unitarity of the transmission probability guarantees the second law of thermodynamics, invalidating Benenti et al.'s argument in the linear-response regime that one could obtain a finite power with the Carnot efficiency under a broken time-reversal symmetry [Phys. Rev. Lett. 106, 230602 (2011), 10.1103/PhysRevLett.106.230602]. These results demonstrate how quantum mechanics constrains thermodynamics.

Spherical Tensor Calculus for Local Adaptive Filtering

NASA Astrophysics Data System (ADS)

Reisert, Marco; Burkhardt, Hans

In 3D image processing tensors play an important role. While rank-1 and rank-2 tensors are well understood and commonly used, higher rank tensors are rare. This is probably due to their cumbersome rotation behavior which prevents a computationally efficient use. In this chapter we want to introduce the notion of a spherical tensor which is based on the irreducible representations of the 3D rotation group. In fact, any ordinary cartesian tensor can be decomposed into a sum of spherical tensors, while each spherical tensor has a quite simple rotation behavior. We introduce so called tensorial harmonics that provide an orthogonal basis for spherical tensor fields of any rank. It is just a generalization of the well known spherical harmonics. Additionally we propose a spherical derivative which connects spherical tensor fields of different degree by differentiation. Based on the proposed theory we present two applications. We propose an efficient algorithm for dense tensor voting in 3D, which makes use of tensorial harmonics decomposition of the tensor-valued voting field. In this way it is possible to perform tensor voting by linear-combinations of convolutions in an efficient way. Secondly, we propose an anisotropic smoothing filter that uses a local shape and orientation adaptive filter kernel which can be computed efficiently by the use spherical derivatives.

Performance Analysis of a Self-Propelling Flat Plate Fin with Joint Compliance

NASA Astrophysics Data System (ADS)

Reddy, N. Srinivasa; Sen, Soumen; Pal, Sumit; Shome, Sankar Nath

2017-12-01

Fish fin muscles are compliant and they regulate the stiffness to suit different swimming conditions. This article attempts to understand the significance of presence of compliance in fin muscle with help of a flexible joint flat plate fin model. Blade element method is employed to model hydrodynamics and to compute the forces of interaction during motion of the plate within fluid. The dynamic model of self-propelling fin is developed through multi-body dynamics approach considering the hydrodynamic forces as external forces acting on the fin. The derived hydrodynamic model is validated with experiments on rigid flat plate fin. The effect of the joint stiffness and flapping frequency on the propulsion speed and efficiency is investigated through simulations using the derived and validated model. The propulsion efficiency is found to be highly influenced by the joint stiffness at a given flapping frequency. The fin attained maximum propulsion efficiency when the joint stiffness is tuned to a value at which flapping frequency matches near natural frequency of the fin. At this tuned joint stiffness and flapping frequency, the resulted Strouhal numbers are observed to fall within the optimum range (0.2 to 0.4) for maximized propulsion efficiency of flying birds and swimming aquatic animals reported in literature.

Constrained Total Generalized p-Variation Minimization for Few-View X-Ray Computed Tomography Image Reconstruction.

PubMed

Zhang, Hanming; Wang, Linyuan; Yan, Bin; Li, Lei; Cai, Ailong; Hu, Guoen

2016-01-01

Total generalized variation (TGV)-based computed tomography (CT) image reconstruction, which utilizes high-order image derivatives, is superior to total variation-based methods in terms of the preservation of edge information and the suppression of unfavorable staircase effects. However, conventional TGV regularization employs l1-based form, which is not the most direct method for maximizing sparsity prior. In this study, we propose a total generalized p-variation (TGpV) regularization model to improve the sparsity exploitation of TGV and offer efficient solutions to few-view CT image reconstruction problems. To solve the nonconvex optimization problem of the TGpV minimization model, we then present an efficient iterative algorithm based on the alternating minimization of augmented Lagrangian function. All of the resulting subproblems decoupled by variable splitting admit explicit solutions by applying alternating minimization method and generalized p-shrinkage mapping. In addition, approximate solutions that can be easily performed and quickly calculated through fast Fourier transform are derived using the proximal point method to reduce the cost of inner subproblems. The accuracy and efficiency of the simulated and real data are qualitatively and quantitatively evaluated to validate the efficiency and feasibility of the proposed method. Overall, the proposed method exhibits reasonable performance and outperforms the original TGV-based method when applied to few-view problems.

Organocatalytic upgrading of furfural and 5-hydroxymethyl furfural to C10 and C12 furoins with quantitative yield and atom-efficiency.

PubMed

Zang, Hongjun; Chen, Eugene Y X

2015-03-30

There is increasing interest in the upgrading of C5 furfural (FF) and C6 5-hydroxymethyl furfural (HMF) into C10 and C12 furoins as higher energy-density intermediates for renewable chemicals, materials, and biofuels. This work utilizes the organocatalytic approach, using the in situ generated N,S-heterocyclic carbene catalyst derived from thiazolium ionic liquids (ILs), to achieve highly efficient self-coupling reactions of FF and HMF. Specifically, variations of the thiazolium IL structure have led to the most active and efficient catalyst system of the current series, which is derived from a new thiazolium IL carrying the electron-donating acetate group at the 5-ring position. For FF coupling by this IL (0.1 mol %, 60 °C, 1 h), when combined with Et3N, furoin was obtained in >99% yield. A 97% yield of the C12 furoin was also achieved from the HMF coupling by this catalyst system (10 mol % loading, 120 °C, 3 h). On the other hand, the thiazolium IL bearing the electron-withdrawing group at the 5-ring position is the least active and efficient catalyst. The mechanistic aspects of the coupling reaction by the thiazolium catalyst system have also been examined and a mechanism has been proposed.

pYEMF, a pUC18-derived XcmI T-vector for efficient cloning of PCR products.

PubMed

Gu, Jingsong; Ye, Chunjiang

2011-03-01

A 1330-bp DNA sequence with two XcmI cassettes was inserted into pUC18 to construct an efficient XcmI T-vector parent plasmid, pYEMF. The large size of the inserted DNA fragment improved T-vector cleavage efficiency, and guaranteed good separation of the molecular components after restriction digestion. The pYEMF-T-vector generated from parent plasmid pYEMF permits blue/white colony screening; cloning efficiency analysis showed that most white colonies (>75%) were putative transformants which carried the cloning product. The sequence analysis and design approach presented here will facilitate applications in the fields of molecular biology and genetic engineering.

Photoelectrochemical hydrogen production from biomass derivatives and water.

PubMed

Lu, Xihong; Xie, Shilei; Yang, Hao; Tong, Yexiang; Ji, Hongbing

2014-11-21

Hydrogen, a clean energy carrier with high energy capacity, is a very promising candidate as a primary energy source for the future. Photoelectrochemical (PEC) hydrogen production from renewable biomass derivatives and water is one of the most promising approaches to producing green chemical fuel. Compared to water splitting, hydrogen production from renewable biomass derivatives and water through a PEC process is more efficient from the viewpoint of thermodynamics. Additionally, the carbon dioxide formed can be re-transformed into carbohydrates via photosynthesis in plants. In this review, we focus on the development of photoanodes and systems for PEC hydrogen production from water and renewable biomass derivatives, such as methanol, ethanol, glycerol and sugars. We also discuss the future challenges and opportunities for the design of the state-of-the-art photoanodes and PEC systems for hydrogen production from biomass derivatives and water.

Green synthesis of chalcones derivatives as intermediate of flavones and their antibacterial activities

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

VH, Elfi Susanti, E-mail: elsantivh@yahoo.com; Redjeki, Tri, E-mail: tri-redjeki@yahoo.com; Matsjeh, Sabirin, E-mail: sabirin-mara@yahoo.com

Four chalcones derivatives have been synthesized from 3,4-dimethoxybenzaldehyde and acetophenone derivatives (2-hydroxy acetophenone, 2,4-dihydroxy acetophenone, 2,5-dihydroxy acetophenone and 2,6-dihydroxy acetophenone). The synthesis of these chalcones were conducted by Claisen-Schmidt condensation using grinding techniques at room temperature in the absence of solvents. The chalcones were prepared by grinding together equivalent amount of the approriate hydroxyacetophenone and 3,4-dimethoxybenzaldehyde in the presence of solid sodium hydroxide. Grinding techniques for synthesis of the chalcones derivatives is simple, efficient and environmentally benign compared to conventional methods. Then, the four chalcones derivatives undergo cyclization reactions to produce four flavones after reacted with iodine. The synthesized compoundsmore » were characterized by spectrometry (IR, {sup 1}H-NMR, {sup 13}C-NMR and MS)« less

Chemical Conversions of Biomass-Derived Platform Chemicals over Copper-Silica Nanocomposite Catalysts.

PubMed

Upare, Pravin P; Hwang, Young Kyu; Lee, Jong-Min; Hwang, Dong Won; Chang, Jong-San

2015-07-20

Biomass and biomass-derived carbohydrates have a high extent of functionality, unlike petroleum, which has limited functionality. In biorefinery applications, the development of methods to control the extent of functionality in final products intended for use as fuels and chemicals is a challenge. In the chemical industry, heterogeneous catalysis is an important tool for the defunctionalization of functionalized feedstocks and biomass-derived platform chemicals to produce value-added chemicals. Herein, we review the recent progress in this field, mainly of vapor phase chemical conversion of biomass-derived C4 -C6 carboxylic acids and esters using copper-silica nanocomposite catalysts. We also demonstrate that these nanocomposite catalysts very efficiently convert biomass-derived platform chemicals into cyclic compounds, such as lactones and hydrofurans, with high selectivities and yields. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Derivation of Rabbit Embryonic Stem Cells from Vitrified–Thawed Embryos

PubMed Central

Chen, Chien-Hong; Li, Yi; Hu, Yeshu; An, Li-You; Yang, Lan; Zhang, Jifeng; Chen, Y. Eugene

2015-01-01

Abstract The rabbit is a useful animal model for regenerative medicine. We previously developed pluripotent rabbit embryonic stem cell (rbESC) lines using fresh embryos. We also successfully cryopreserved rabbit embryos by vitrification. In the present work, we combined these two technologies to derive rbESCs using vitrified–thawed (V/T) embryos. We demonstrate that V/T blastocysts (BLs) can be used to derive pluripotent rbESCs with efficiencies comparable to those using fresh BLs. These ESCs are undistinguishable from the ones derived from fresh embryos. We tested the developmental capacity of rbESCs derived from V/T embryos by BL injection experiments and produced chimeric kits. Our work adds cryopreservation to the toolbox of rabbit stem cell research and applications and will greatly expand the available research materials for regenerative medicine in a clinically relevant animal model. PMID:26579970

Catalytic combustion of coal-derived liquids

NASA Technical Reports Server (NTRS)

Bulzan, D. L.; Tacina, R. R.

1981-01-01

A noble metal catalytic reactor was tested with three grades of SRC 2 coal derived liquids, naphtha, middle distillate, and a blend of three parts middle distillate to one part heavy distillate. A petroleum derived number 2 diesel fuel was also tested to provide a direct comparison. The catalytic reactor was tested at inlet temperatures from 600 to 800 K, reference velocities from 10 to 20 m/s, lean fuel air ratios, and a pressure of 3 x 10 to the 5th power Pa. Compared to the diesel, the naphtha gave slightly better combustion efficiency, the middle distillate was almost identical, and the middle heavy blend was slightly poorer. The coal derived liquid fuels contained from 0.58 to 0.95 percent nitrogen by weight. Conversion of fuel nitrogen to NOx was approximately 75 percent for all three grades of the coal derived liquids.

Plant derived edible nanoparticles as a new therapeutic approach against diseases

PubMed Central

Zhang, Mingzhen; Viennois, Emilie; Xu, Changlong; Merlin, Didier

2016-01-01

ABSTRACT In plant cells, nanoparticles containing miRNA, bioactive lipids and proteins serve as extracellular messengers to mediate cell-cell communication in a manner similar to the exosomes secreted by mammalian cells. Notably, such nanoparticles are edible. Moreover, given the proper origin and cargo, plant derived edible nanoparticles could function in interspecies communication and may serve as natural therapeutics against a variety of diseases. In addition, nanoparticles made of plant-derived lipids may be used to efficiently deliver specific drugs. Plant derived edible nanoparticles could be more easily scaled up for mass production, compared to synthetic nanoparticles. In this review, we discuss recent significant developments pertaining to plant derived edible nanoparticles and provide insight into the use of plants as a bio-renewable, sustainable, diversified platform for the production of therapeutic nanoparticles. PMID:27358751

A Survey of Validation Strategies for CRISPR-Cas9 Editing.

PubMed

Sentmanat, Monica F; Peters, Samuel T; Florian, Colin P; Connelly, Jon P; Pruett-Miller, Shondra M

2018-01-17

The T7 endonuclease 1 (T7E1) mismatch detection assay is a widely used method for evaluating the activity of site-specific nucleases, such as the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system. To determine the accuracy and sensitivity of this assay, we compared the editing estimates derived by the T7E1 assay with that of targeted next-generation sequencing (NGS) in pools of edited mammalian cells. Here, we report that estimates of nuclease activity determined by T7E1 most often do not accurately reflect the activity observed in edited cells. Editing efficiencies of CRISPR-Cas9 complexes with similar activity by T7E1 can prove dramatically different by NGS. Additionally, we compared editing efficiencies predicted by the Tracking of Indels by Decomposition (TIDE) assay and the Indel Detection by Amplicon Analysis (IDAA) assay to that observed by targeted NGS for both cellular pools and single-cell derived clones. We show that targeted NGS, TIDE, and IDAA assays predict similar editing efficiencies for pools of cells but that TIDE and IDAA can miscall alleles in edited clones.

Spatio-temporal Convergence of Maximum Daily Light-Use Efficiency Based on Radiation Absorption by Canopy Chlorophyll

DOE PAGES

Zhang, Yao; Xiao, Xiangming; Wolf, Sebastian; ...

2018-04-03

Light-use efficiency (LUE), which quantifies the plants’ efficiency in utilizing solar radiation for photosynthetic carbon fixation, is an important factor for gross primary production (GPP) estimation. Here we use satellite-based solar-induced chlorophyll fluorescence (SIF) as a proxy for photosynthetically active radiation absorbed by chlorophyll (APAR chl) and derive an estimation of the fraction of APAR chl (fPAR chl) from four remotely-sensed vegetation indicators. By comparing maximum LUE estimated at different scales from 127 eddy flux sites, we found that the maximum daily LUE based on PAR absorption by canopy chlorophyll (εmore » $$chl\\atop{max}$$), unlike other expressions of LUE, tends to converge across biome types. The photosynthetic seasonality in tropical forests can also be tracked by the change of fPAR chl, suggesting the corresponding (ε$$chl\\atop{max}$$}$) to have less seasonal variation. Finally, this spatio-temporal convergence of LUE derived from fPAR chl can be used to build simple but robust GPP models and to better constrain process-based models.« less

Onion-derived N, S self-doped carbon materials as highly efficient metal-free electrocatalysts for the oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Yang, Shuting; Mao, Xinxin; Cao, Zhaoxia; Yin, Yanhong; Wang, Zhichao; Shi, Mengjiao; Dong, Hongyu

2018-01-01

Onion-derived nitrogen, sulfur self-doped nanoporous carbon spheres (NSC) as efficient metal-free electrocatalyst were synthesized via a facile hydrothermal and subsequent pyrolysis process. The typical NSC with a high BET specific surface area of 1558 m2 g-1, contains 6.23 at.% N and 0.36 at.% S, and possesses high concentration of pyridinic and graphitic nitrogen species. Experimentally, the best performance was the NSC-A2 which showed excellent catalytic activity to oxygen reduction reaction via a 4 electron mechanism with an onset potential of 0.88 V (vs. RHE), and a superior stability comparable to commercial Pt/C catalyst. The high electrocatalytic activity is attributed to not only the synergistic effect of N and S dual doping in carbon and the sufficient active sites, but also its high BET specific surface area and suitable microporous structure. The results demonstrate that it is a simple and scalable approach for preparing efficient and low-cost carbon-based electrocatalysts for oxygen reduction reaction.

Spatio-temporal Convergence of Maximum Daily Light-Use Efficiency Based on Radiation Absorption by Canopy Chlorophyll

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

Zhang, Yao; Xiao, Xiangming; Wolf, Sebastian

Light-use efficiency (LUE), which quantifies the plants’ efficiency in utilizing solar radiation for photosynthetic carbon fixation, is an important factor for gross primary production (GPP) estimation. Here we use satellite-based solar-induced chlorophyll fluorescence (SIF) as a proxy for photosynthetically active radiation absorbed by chlorophyll (APAR chl) and derive an estimation of the fraction of APAR chl (fPAR chl) from four remotely-sensed vegetation indicators. By comparing maximum LUE estimated at different scales from 127 eddy flux sites, we found that the maximum daily LUE based on PAR absorption by canopy chlorophyll (εmore » $$chl\\atop{max}$$), unlike other expressions of LUE, tends to converge across biome types. The photosynthetic seasonality in tropical forests can also be tracked by the change of fPAR chl, suggesting the corresponding (ε$$chl\\atop{max}$$}$) to have less seasonal variation. Finally, this spatio-temporal convergence of LUE derived from fPAR chl can be used to build simple but robust GPP models and to better constrain process-based models.« less

Feature extraction using first and second derivative extrema (FSDE) for real-time and hardware-efficient spike sorting.

PubMed

Paraskevopoulou, Sivylla E; Barsakcioglu, Deren Y; Saberi, Mohammed R; Eftekhar, Amir; Constandinou, Timothy G

2013-04-30

Next generation neural interfaces aspire to achieve real-time multi-channel systems by integrating spike sorting on chip to overcome limitations in communication channel capacity. The feasibility of this approach relies on developing highly efficient algorithms for feature extraction and clustering with the potential of low-power hardware implementation. We are proposing a feature extraction method, not requiring any calibration, based on first and second derivative features of the spike waveform. The accuracy and computational complexity of the proposed method are quantified and compared against commonly used feature extraction methods, through simulation across four datasets (with different single units) at multiple noise levels (ranging from 5 to 20% of the signal amplitude). The average classification error is shown to be below 7% with a computational complexity of 2N-3, where N is the number of sample points of each spike. Overall, this method presents a good trade-off between accuracy and computational complexity and is thus particularly well-suited for hardware-efficient implementation. Copyright © 2013 Elsevier B.V. All rights reserved.

Nucleophilic catalysis of MeON-neoglycoside formation by aniline derivatives.

PubMed

Loskot, Steven A; Zhang, Jianjun; Langenhan, Joseph M

2013-12-06

Neoglycosylations are increasingly being employed in the synthesis of natural products, drug candidates, glycopeptide mimics, oligosaccharide analogues, and other applications, but the efficiency of these reactions is usually limited by slow reaction times. Here, we show that aniline derivatives such as 2-amino-5-methoxybenzoic acid enhance the rate of acid-catalyzed neoglycosylation for a range of sugar substrates up to a factor of 32 relative to the uncatalyzed reaction.

Basic Economic Principles

NASA Technical Reports Server (NTRS)

Tideman, T. N.

1972-01-01

An economic approach to design efficient transportation systems involves maximizing an objective function that reflects both goals and costs. A demand curve can be derived by finding the quantities of a good that solve the maximization problem as one varies the price of that commodity, holding income and the prices of all other goods constant. A supply curve is derived by applying the idea of profit maximization of firms. The production function determines the relationship between input and output.

Efficient and Convenient Synthesis of 1,8-Dioxodecahydroacridine Derivatives Using Cu-Doped ZnO Nanocrystalline Powder as a Catalyst under Solvent-Free Conditions

PubMed Central

Alinezhad, Heshmatollah; Mohseni Tavakkoli, Sahar

2013-01-01

A simple and convenient one-step method for synthesis of acridines and their derivatives from condensation of aromatic aldehydes, cyclic diketones, and aryl amines using Cu-doped ZnO nanocrystalline powder as a catalyst is reported. The present protocol provides several advantages such as good yields, short reaction time, easy workup, and simplicity in operation. PMID:24294130

Preliminary Results from the Application of Automated Adjoint Code Generation to CFL3D

NASA Technical Reports Server (NTRS)

Carle, Alan; Fagan, Mike; Green, Lawrence L.

1998-01-01

This report describes preliminary results obtained using an automated adjoint code generator for Fortran to augment a widely-used computational fluid dynamics flow solver to compute derivatives. These preliminary results with this augmented code suggest that, even in its infancy, the automated adjoint code generator can accurately and efficiently deliver derivatives for use in transonic Euler-based aerodynamic shape optimization problems with hundreds to thousands of independent design variables.

High-order fractional partial differential equation transform for molecular surface construction.

PubMed

Hu, Langhua; Chen, Duan; Wei, Guo-Wei

2013-01-01

Fractional derivative or fractional calculus plays a significant role in theoretical modeling of scientific and engineering problems. However, only relatively low order fractional derivatives are used at present. In general, it is not obvious what role a high fractional derivative can play and how to make use of arbitrarily high-order fractional derivatives. This work introduces arbitrarily high-order fractional partial differential equations (PDEs) to describe fractional hyperdiffusions. The fractional PDEs are constructed via fractional variational principle. A fast fractional Fourier transform (FFFT) is proposed to numerically integrate the high-order fractional PDEs so as to avoid stringent stability constraints in solving high-order evolution PDEs. The proposed high-order fractional PDEs are applied to the surface generation of proteins. We first validate the proposed method with a variety of test examples in two and three-dimensional settings. The impact of high-order fractional derivatives to surface analysis is examined. We also construct fractional PDE transform based on arbitrarily high-order fractional PDEs. We demonstrate that the use of arbitrarily high-order derivatives gives rise to time-frequency localization, the control of the spectral distribution, and the regulation of the spatial resolution in the fractional PDE transform. Consequently, the fractional PDE transform enables the mode decomposition of images, signals, and surfaces. The effect of the propagation time on the quality of resulting molecular surfaces is also studied. Computational efficiency of the present surface generation method is compared with the MSMS approach in Cartesian representation. We further validate the present method by examining some benchmark indicators of macromolecular surfaces, i.e., surface area, surface enclosed volume, surface electrostatic potential and solvation free energy. Extensive numerical experiments and comparison with an established surface model indicate that the proposed high-order fractional PDEs are robust, stable and efficient for biomolecular surface generation.

A Polymeric Prodrug of 5-Fluorouracil-1-Acetic Acid Using a Multi-Hydroxyl Polyethylene Glycol Derivative as the Drug Carrier

PubMed Central

Sun, Xun; Gong, Tao; Zhang, Zhirong

2014-01-01

Purpose Macromolecular prodrugs obtained by covalently conjugating small molecular drugs with polymeric carriers were proven to accomplish controlled and sustained release of the therapeutic agents in vitro and in vivo. Polyethylene glycol (PEG) has been extensively used due to its low toxicity, low immunogenicity and high biocompatibility. However, for linear PEG macromolecules, the number of available hydroxyl groups for drug coupling does not change with the length of polymeric chain, which limits the application of PEG for drug conjugation purposes. To increase the drug loading and prolong the retention time of 5-fluorouracil (5-Fu), a macromolecular prodrug of 5-Fu, 5-fluorouracil-1 acid-PAE derivative (5-FA-PAE) was synthesized and tested for the antitumor activity in vivo. Methods PEG with a molecular weight of 38 kDa was selected to synthesize the multi-hydroxyl polyethylene glycol derivative (PAE) through an addition reaction. 5-fluorouracil-1 acetic acid (5-FA), a 5-Fu derivative was coupled with PEG derivatives via ester bond to form a macromolecular prodrug, 5-FA-PAE. The in vitro drug release, pharmacokinetics, in vivo distribution and antitumor effect of the prodrug were investigated, respectively. Results The PEG-based prodrug obtained in this study possessed an exceedingly high 5-FA loading efficiency of 10.58%, much higher than the maximum drug loading efficiency of unmodified PEG with the same molecular weight, which was 0.98% theoretically. Furthermore, 5-FA-PAE exhibited suitable sustained release in tumors. Conclusion This study provides a new approach for the development of the delivery to tumors of anticancer agents with PEG derivatives. PMID:25389968

Kinetics and the mass transfer mechanism of hydrogen sulfide removal by biochar derived from rice hull.

PubMed

Shang, Guofeng; Liu, Liang; Chen, Ping; Shen, Guoqing; Li, Qiwu

2016-05-01

The biochar derived from rice hull was evaluated for its abilities to remove hydrogen sulfide (H2S) from gas phase. The surface area and pH of the biochar were compared. The biochar derived from rice hull was evaluated for its abilities to remove hydrogen sulfide (H2S) from gas phase. The surface area and pH of the biochar were compared. The different pyrolysis temperature has great influence on the adsorption of H2S. At the different pyrolysis temperature, the H2S removal efficiency of rice hull-derived biochar was different. The adsorption capacities of biochar were 2.09 mg·g(-1), 2.65 mg·g(-1), 16.30 mg·g(-1), 20.80 mg·g(-1), and 382.70 mg·g(-1), which their pyrolysis temperatures were 100 °C, 200 °C, 300 °C, 400 °C and 500 °C respectively. Based on the Yoon-Nelson model, it analyzed the mass transfer mechanism of hydrogen sulfide adsorption by biochar. The paper focuses on the biochar derived from rice hull-removed hydrogen sulfide (H2S) from gas phase. The surface area and pH of the biochar were compared. The different pyrolysis temperatures have great influence on the adsorption of H2S. At the different pyrolysis temperatures, the H2S removal efficiency of rice hull-derived biohar was different. The adsorption capacities of biochar were 2.09, 2.65, 16.30, 20.80, and 382.70 mg·g(-1), and their pyrolysis temperatures were 100, 200, 300, 400, and 500 °C, respectively. Based on the Yoon-Nelson model, the mass transfer mechanism of hydrogen sulfide adsorption by biochar was analyzed.

Selective binding to transthyretin and tetramer stabilization in serum from patients with familial amyloidotic polyneuropathy by an iodinated diflunisal derivative

PubMed Central

2004-01-01

In familial amyloidotic polyneuropathy, TTR (transthyretin) variants are deposited as amyloid fibrils. It is thought that this process involves TTR tetramer dissociation, which leads to partially unfolded monomers that aggregate and polymerize into amyloid fibrils. This process can be counteracted by stabilization of the tetramer. Several small compounds, such as diclofenac, diflunisal and flufenamic acid, have been reported to bind to TTR in vitro, in the T4 (thyroxine) binding channel that runs through the TTR tetramer, and consequently are considered to stabilize TTR. However, if these agents bind plasma proteins other than TTR, decreased drug availability will occur, compromising their use as therapeutic agents for TTR amyloidosis. In the present work, we compared the action of these compounds and of new derivatives designed to increase both selectivity of binding to TTR and inhibitory potency in relation to TTR amyloid fibril formation. We found two diflunisal derivatives that, in contrast with diclofenac, flufenamic acid and diflunisal, displaced T4 from TTR in plasma preferentially over binding to albumin and thyroxine binding globulin. The same diflunisal derivatives also had a stabilizing effect on TTR tetramers in plasma, as studied by isoelectric focusing of whole plasma under semi-denaturing conditions. In addition, by transmission electron microscopy, we demonstrated that, in contrast with other proposed TTR stabilizers (namely diclofenac, flufenamic acid and diflunisal), one of the diflunisal derivatives tested efficiently inhibited TTR aggregation. Taken together, our ex vivo and in vitro studies present evidence for the selectivity and efficiency of novel diflunisal derivates as TTR stabilizers and as inhibitors of fibril formation. PMID:15080795

Photophysical properties and computational investigation on substituent effects on the structural and electronic properties of 3,6-di(thiophene-2-yl)-carbazole-based derivatives

NASA Astrophysics Data System (ADS)

Sriyab, Suwannee; Gleeson, Matthew Paul; Hannongbua, Supa; Suramitr, Songwut

2016-12-01

A series of 3,6-carbazole-based derivatives, 3,6-CzTh-(1), 3,6-CzTh-(2), 3,6-CzTh-(3) and 3,6-CzTh-(4), were synthesized to investigate the influence of structural distortion on intramolecular charge transfer (ICT) complexation between the conjugation components and carbazole core unit of the 3,6-carbazole-based derivatives. The 3,6-carbazole-based derivatives were synthesized and analysed using UV-Visible, photoluminescence spectroscopy and DFT calculations. The electron-donating substituents on the carbazole core unit, which was linked by formyl and acetyl at the 3,6-positions of the carbazole core so as to directly involve the electron-donating edge substituents in backbone, exhibited conjugation breaks in the middle of the carbazole core units. The break lead to a planar structure with an extraordinary ability to stabilize on the excited state resulting in a strong fluorescence quantum yield (Фfluo ≈ 0.6-0.7). The results of the Time-dependent density functional theory (TD-DFT) calculations were in agreement with the experimental results, and indicated that the low fluorescence of 3,6-CzTh-(1) and 3,6-CzTh-(2) is derived not only from intersystem crossing but also from internal conversion due to the proximity effect; this inference was also supported by the measurements of the photoluminescence spectra at low temperatures. In addition, factors leading efficiently to non-radiative processes were shown to be absent in 3,6-CzTh-(3) and 3,6-CzTh-(4). This work deepens our understanding of 3,6-di(thiophen-2-yl)-carbazole-based derivatives and provides insight into the future design of novel materials for improved fluorescence efficiencies and optoelectronic devices.

Local coding based matching kernel method for image classification.

PubMed

Song, Yan; McLoughlin, Ian Vince; Dai, Li-Rong

2014-01-01

This paper mainly focuses on how to effectively and efficiently measure visual similarity for local feature based representation. Among existing methods, metrics based on Bag of Visual Word (BoV) techniques are efficient and conceptually simple, at the expense of effectiveness. By contrast, kernel based metrics are more effective, but at the cost of greater computational complexity and increased storage requirements. We show that a unified visual matching framework can be developed to encompass both BoV and kernel based metrics, in which local kernel plays an important role between feature pairs or between features and their reconstruction. Generally, local kernels are defined using Euclidean distance or its derivatives, based either explicitly or implicitly on an assumption of Gaussian noise. However, local features such as SIFT and HoG often follow a heavy-tailed distribution which tends to undermine the motivation behind Euclidean metrics. Motivated by recent advances in feature coding techniques, a novel efficient local coding based matching kernel (LCMK) method is proposed. This exploits the manifold structures in Hilbert space derived from local kernels. The proposed method combines advantages of both BoV and kernel based metrics, and achieves a linear computational complexity. This enables efficient and scalable visual matching to be performed on large scale image sets. To evaluate the effectiveness of the proposed LCMK method, we conduct extensive experiments with widely used benchmark datasets, including 15-Scenes, Caltech101/256, PASCAL VOC 2007 and 2011 datasets. Experimental results confirm the effectiveness of the relatively efficient LCMK method.

Time-splitting combined with exponential wave integrator fourier pseudospectral method for Schrödinger-Boussinesq system

NASA Astrophysics Data System (ADS)

Liao, Feng; Zhang, Luming; Wang, Shanshan

2018-02-01

In this article, we formulate an efficient and accurate numerical method for approximations of the coupled Schrödinger-Boussinesq (SBq) system. The main features of our method are based on: (i) the applications of a time-splitting Fourier spectral method for Schrödinger-like equation in SBq system, (ii) the utilizations of exponential wave integrator Fourier pseudospectral for spatial derivatives in the Boussinesq-like equation. The scheme is fully explicit and efficient due to fast Fourier transform. The numerical examples are presented to show the efficiency and accuracy of our method.

Tracking of Indels by DEcomposition is a Simple and Effective Method to Assess Efficiency of Guide RNAs in Zebrafish.

PubMed

Etard, Christelle; Joshi, Swarnima; Stegmaier, Johannes; Mikut, Ralf; Strähle, Uwe

2017-12-01

A bottleneck in CRISPR/Cas9 genome editing is variable efficiencies of in silico-designed gRNAs. We evaluated the sensitivity of the TIDE method (Tracking of Indels by DEcomposition) introduced by Brinkman et al. in 2014 for assessing the cutting efficiencies of gRNAs in zebrafish. We show that this simple method, which involves bulk polymerase chain reaction amplification and Sanger sequencing, is highly effective in tracking well-performing gRNAs in pools of genomic DNA derived from injected embryos. The method is equally effective for tracing INDELs in heterozygotes.

Unitary limit in crossed Andreev transport

DOE PAGES

Sadovskyy, I. A.; Lesovik, G. B.; Vinokur, V. M.

2015-10-08

One of the most promising approaches for generating spin- and energy-entangled electron pairs is splitting a Cooper pair into the metal through spatially separated terminals. Utilizing hybrid systems with the energy-dependent barriers at the superconductor/normal metal (NS) interfaces, one can achieve a practically 100% efficiency outcome of entangled electrons. We investigate a minimalistic one-dimensional model comprising a superconductor and two metallic leads and derive an expression for an electron-to-hole transmission probability as a measure of splitting efficiency. We find the conditions for achieving 100% efficiency and present analytical results for the differential conductance and differential noise.

Signal recognition efficiencies of artificial neural-network pulse-shape discrimination in HPGe -decay searches

NASA Astrophysics Data System (ADS)

Caldwell, A.; Cossavella, F.; Majorovits, B.; Palioselitis, D.; Volynets, O.

2015-07-01

A pulse-shape discrimination method based on artificial neural networks was applied to pulses simulated for different background, signal and signal-like interactions inside a germanium detector. The simulated pulses were used to investigate variations of efficiencies as a function of used training set. It is verified that neural networks are well-suited to identify background pulses in true-coaxial high-purity germanium detectors. The systematic uncertainty on the signal recognition efficiency derived using signal-like evaluation samples from calibration measurements is estimated to be 5 %. This uncertainty is due to differences between signal and calibration samples.

Development of Highly Fluorescent Materials Based on Thiophenylimidazole Dyes

NASA Technical Reports Server (NTRS)

Santos, Javier; Bu, Xiu R.; Mintz, Eric A.; Meador, Michael A. (Technical Monitor)

2000-01-01

Organic fluorescent materials are expected to find many potential applications in optical devices and photo-functionalized materials. Although many investigations have been focused on heterocyclic compounds such as coumarins, bipyridines, rhodamines, and pyrrole derivatives, little is known for fluorescent imidazole materials. We discovered that one particular class of imidazole derivatives is highly fluorescent. A series of monomeric and polymeric based fluorescent dyes were prepared containing a thiophene unit at the second position of the imidazole ring. Dependence of fluorescence efficiency on parameters such as solvent polarity and substituent groups has been investigated. It was found that a formyl group at the 2-position of the thiophene ring dramatically enhance fluorescence properties. Ion recognition probes indicated their potential as sensor materials. These fluorophores have flexibility for introduction of versatile substituent groups that could improve the fluorescence efficiency and sensor properties.

RxTerms - a drug interface terminology derived from RxNorm.

PubMed

Fung, Kin Wah; McDonald, Clement; Bray, Bruce E

2008-11-06

A good interface terminology is an essential component of any Computerized Provider Order Entry system. RxTerms is a drug interface terminology derived from RxNorm. By reorganizing the drug information into two dimensions as prescribers do when writing prescriptions and by eliminating drug names that are less likely to be needed in a prescribing environment, RxTerms helps the user to efficiently enter complete prescription orders. Preliminary evaluation of RxTerms using a list of most commonly prescribed drugs showed that its coverage was very good (99% for both generic and branded drug names). There was significant efficiency gain compared to using the unprocessed RxNorm names. RxTerms fills the gap for a free, up-to-date drug interface terminology that is linked to RxNorm, the U.S. designated standard for clinical drugs.

Acetaldehyde as an intermediate in the electroreduction of carbon monoxide to ethanol on oxide-derived copper

DOE PAGES

Bertheussen, Erlend; Verdaguer-Casadevall, Arnau; Ravasio, Davide; ...

2015-12-21

Oxide-derived copper (OD-Cu) electrodes exhibit unprecedented CO reduction performance towards liquid fuels, producing ethanol and acetate with >50 % Faradaic efficiency at -0.3 V (vs. RHE). By using static headspace-gas chromatography for liquid phase analysis, we identify acetaldehyde as a minor product and key intermediate in the electroreduction of CO to ethanol on OD-Cu electrodes. Acetaldehyde is produced with a Faradaic efficiency of ≈5 % at -0.33 V (vs. RHE). We show that acetaldehyde forms at low steady-state concentrations, and that free acetaldehyde is difficult to detect in alkaline solutions using NMR spectroscopy, requiring alternative methods for detection and quantification.more » Our results indicate an important step towards understanding the CO reduction mechanism on OD-Cu electrodes.« less

Nonlinear optical studies and structure-activity relationship of chalcone derivatives with in silico insights

NASA Astrophysics Data System (ADS)

Kar, Swayamsiddha; Adithya, K. S.; Shankar, Pruthvik; Jagadeesh Babu, N.; Srivastava, Sailesh; Nageswara Rao, G.

2017-07-01

Nine chalcones were prepared via Claisen-Schmidt condensation, and characterized by UV-vis, IR, 1H NMR, 13C NMR and mass spectrometry. One of the representative member 4-NDM-TC has been studied via single crystal XRD and the TGA/DTA technique. SHG efficiency and NLO susceptibilities of the chalcones have been evaluated by the Kurtz and Perry method and Degenerate Four Wave Mixing techniques respectively. 3-Cl-4‧-HC was noted to possess SHG efficiency 1.37 times that of urea while 4-NDM-TC returned the highest third order NLO susceptibilities with respect to CS2. In silico studies help evaluate various physical parameters, in correlating the observed activities. In conclusion, the structure-activity relationship was derived based on the in silico and experimental results for the third order NLO susceptibilities.

Validation of spatially resolved all sky imager derived DNI nowcasts

NASA Astrophysics Data System (ADS)

Kuhn, Pascal; Wilbert, Stefan; Schüler, David; Prahl, Christoph; Haase, Thomas; Ramirez, Lourdes; Zarzalejo, Luis; Meyer, Angela; Vuilleumier, Laurent; Blanc, Philippe; Dubrana, Jean; Kazantzidis, Andreas; Schroedter-Homscheidt, Marion; Hirsch, Tobias; Pitz-Paal, Robert

2017-06-01

Mainly due to clouds, Direct Normal Irradiance (DNI) displays short-term local variabilities affecting the efficiency of concentrating solar power (CSP) plants. To enable efficient plant operation, DNI nowcasts in high spatial and temporal resolutions for 15 to 30 minutes ahead are required. Ground-based All Sky Imagers (ASI) can be used to detect, track and predict 3D positions of clouds possibly shading the plant. The accuracy and reliability of these ASI-derived DNI nowcasts must be known to allow its application in solar power plants. Within the framework of the European project DNICast, an ASI-based nowcasting system was developed and implemented at the Plataforma Solar de Almería (PSA). Its validation methodology and validation results are presented in this work. The nowcasting system outperforms persistence forecasts for volatile irradiance situations.

Both TALENs and CRISPR/Cas9 directly target the HBB IVS2–654 (C > T) mutation in β-thalassemia-derived iPSCs

PubMed Central

Xu, Peng; Tong, Ying; Liu, Xiu-zhen; Wang, Ting-ting; Cheng, Li; Wang, Bo-yu; Lv, Xiang; Huang, Yue; Liu, De-pei

2015-01-01

β-Thalassemia is one of the most common genetic blood diseases and is caused by either point mutations or deletions in the β-globin (HBB) gene. The generation of patient-specific induced pluripotent stem cells (iPSCs) and subsequent correction of the disease-causing mutations may be a potential therapeutic strategy for this disease. Due to the low efficiency of typical homologous recombination, endonucleases, including TALENs and CRISPR/Cas9, have been widely used to enhance the gene correction efficiency in patient-derived iPSCs. Here, we designed TALENs and CRISPR/Cas9 to directly target the intron2 mutation site IVS2-654 in the globin gene. We observed different frequencies of double-strand breaks (DSBs) at IVS2-654 loci using TALENs and CRISPR/Cas9, and TALENs mediated a higher homologous gene targeting efficiency compared to CRISPR/Cas9 when combined with the piggyBac transposon donor. In addition, more obvious off-target events were observed for CRISPR/Cas9 compared to TALENs. Finally, TALENs-corrected iPSC clones were selected for erythroblast differentiation using the OP9 co-culture system and detected relatively higher transcription of HBB than the uncorrected cells. This comparison of using TALENs or CRISPR/Cas9 to correct specific HBB mutations in patient-derived iPSCs will guide future applications of TALENs- or CRISPR/Cas9-based gene therapies in monogenic diseases. PMID:26156589

A conceptual study of the potential for automotive-derived and free-piston Stirling engines in 30- to 400-kilowatt stationary power applications

NASA Technical Reports Server (NTRS)

Vatsky, A.; Chen, H. S.; Dineen, J.

1982-01-01

The technical feasibility of applying automotive-derived kinematic and free-piston Stirling engine concepts for stationary applications was explored. Automotive-derived engines offer cost advantages by providing a mature and developd engine technology base with downrating and parts commonality options for specific applications. Two engine sizes (30 and 400 kW), two Stirling engine configurations (kinematic and free-piston), and two output systems (crankshaft and hydraulic pump) were studied. The study includes the influences of using either hydrogen or helium as the working gas. The first kinematic configuration selects an existing Stirling engine design from an automotive application and adapts it to stationary requirements. A 50,000-hour life requirement was established by downrating the engine to 40 kW and reducing auxiliary loads. Efficiency improvements were gained by selective material and geometric variations and peak brake efficiency of 36.8 percent using helium gas was achieved. The second design was a four-cylinder, 400 kW engine, utilizing a new output drive system known as the z-crank, which provides lower friction losses and variable stroke power control. Three different material and working gas combinations were considered. Brake efficiency levels varied from 40.5 percent to 45.6 percent. A 37.5 kW single-cycle, free-piston hydraulic output design was generated by scaling one cylinder of the original automotive engine and mating it to a counterbalanced reciprocal hydraulic pump. Metallic diaphragms were utilized to transmit power.

Tailored HIV-1 vectors for genetic modification of primary human dendritic cells and monocytes.

PubMed

Durand, Stéphanie; Nguyen, Xuan-Nhi; Turpin, Jocelyn; Cordeil, Stephanie; Nazaret, Nicolas; Croze, Séverine; Mahieux, Renaud; Lachuer, Joël; Legras-Lachuer, Catherine; Cimarelli, Andrea

2013-01-01

Monocyte-derived dendritic cells (MDDCs) play a key role in the regulation of the immune system and are the target of numerous gene therapy applications. The genetic modification of MDDCs is possible with human immunodeficiency virus type 1 (HIV-1)-derived lentiviral vectors (LVs) but requires high viral doses to bypass their natural resistance to viral infection, and this in turn affects their physiological properties. To date, a single viral protein is able to counter this restrictive phenotype, Vpx, a protein derived from members of the HIV-2/simian immunodeficiency virus SM lineage that counters at least two restriction factors present in myeloid cells. By tagging Vpx with a short heterologous membrane-targeting domain, we have obtained HIV-1 LVs incorporating high levels of this protein (HIV-1-Src-Vpx). These vectors efficiently transduce differentiated MDDCs and monocytes either as previously purified populations or as populations within unsorted peripheral blood mononuclear cells (PBMCs). In addition, these vectors can be efficiently pseudotyped with receptor-specific envelopes, further restricting their cellular tropism almost uniquely to MDDCs. Compared to conventional HIV-1 LVs, these novel vectors allow for an efficient genetic modification of MDDCs and, more importantly, do not cause their maturation or affect their survival, which are unwanted side effects of the transduction process. This study describes HIV-1-Src-Vpx LVs as a novel potent tool for the genetic modification of differentiated MDDCs and of circulating monocyte precursors with strong potential for a wide range of gene therapy applications.

Both TALENs and CRISPR/Cas9 directly target the HBB IVS2-654 (C > T) mutation in β-thalassemia-derived iPSCs.

PubMed

Xu, Peng; Tong, Ying; Liu, Xiu-zhen; Wang, Ting-ting; Cheng, Li; Wang, Bo-yu; Lv, Xiang; Huang, Yue; Liu, De-pei

2015-07-09

β-Thalassemia is one of the most common genetic blood diseases and is caused by either point mutations or deletions in the β-globin (HBB) gene. The generation of patient-specific induced pluripotent stem cells (iPSCs) and subsequent correction of the disease-causing mutations may be a potential therapeutic strategy for this disease. Due to the low efficiency of typical homologous recombination, endonucleases, including TALENs and CRISPR/Cas9, have been widely used to enhance the gene correction efficiency in patient-derived iPSCs. Here, we designed TALENs and CRISPR/Cas9 to directly target the intron2 mutation site IVS2-654 in the globin gene. We observed different frequencies of double-strand breaks (DSBs) at IVS2-654 loci using TALENs and CRISPR/Cas9, and TALENs mediated a higher homologous gene targeting efficiency compared to CRISPR/Cas9 when combined with the piggyBac transposon donor. In addition, more obvious off-target events were observed for CRISPR/Cas9 compared to TALENs. Finally, TALENs-corrected iPSC clones were selected for erythroblast differentiation using the OP9 co-culture system and detected relatively higher transcription of HBB than the uncorrected cells. This comparison of using TALENs or CRISPR/Cas9 to correct specific HBB mutations in patient-derived iPSCs will guide future applications of TALENs- or CRISPR/Cas9-based gene therapies in monogenic diseases.

A conceptual study of the potential for automotive-derived and free-piston Stirling engines in 30- to 400-kilowatt stationary power applications

NASA Astrophysics Data System (ADS)

Vatsky, A.; Chen, H. S.; Dineen, J.

1982-05-01

The technical feasibility of applying automotive-derived kinematic and free-piston Stirling engine concepts for stationary applications was explored. Automotive-derived engines offer cost advantages by providing a mature and developd engine technology base with downrating and parts commonality options for specific applications. Two engine sizes (30 and 400 kW), two Stirling engine configurations (kinematic and free-piston), and two output systems (crankshaft and hydraulic pump) were studied. The study includes the influences of using either hydrogen or helium as the working gas. The first kinematic configuration selects an existing Stirling engine design from an automotive application and adapts it to stationary requirements. A 50,000-hour life requirement was established by downrating the engine to 40 kW and reducing auxiliary loads. Efficiency improvements were gained by selective material and geometric variations and peak brake efficiency of 36.8 percent using helium gas was achieved. The second design was a four-cylinder, 400 kW engine, utilizing a new output drive system known as the z-crank, which provides lower friction losses and variable stroke power control. Three different material and working gas combinations were considered. Brake efficiency levels varied from 40.5 percent to 45.6 percent. A 37.5 kW single-cycle, free-piston hydraulic output design was generated by scaling one cylinder of the original automotive engine and mating it to a counterbalanced reciprocal hydraulic pump. Metallic diaphragms were utilized to transmit power.

Improving smoothing efficiency of rigid conformal polishing tool using time-dependent smoothing evaluation model

NASA Astrophysics Data System (ADS)

Song, Chi; Zhang, Xuejun; Zhang, Xin; Hu, Haifei; Zeng, Xuefeng

2017-06-01

A rigid conformal (RC) lap can smooth mid-spatial-frequency (MSF) errors, which are naturally smaller than the tool size, while still removing large-scale errors in a short time. However, the RC-lap smoothing efficiency performance is poorer than expected, and existing smoothing models cannot explicitly specify the methods to improve this efficiency. We presented an explicit time-dependent smoothing evaluation model that contained specific smoothing parameters directly derived from the parametric smoothing model and the Preston equation. Based on the time-dependent model, we proposed a strategy to improve the RC-lap smoothing efficiency, which incorporated the theoretical model, tool optimization, and efficiency limit determination. Two sets of smoothing experiments were performed to demonstrate the smoothing efficiency achieved using the time-dependent smoothing model. A high, theory-like tool influence function and a limiting tool speed of 300 RPM were o

Electron-hole pairs generation rate estimation irradiated by isotope Nickel-63 in silicone using GEANT4

NASA Astrophysics Data System (ADS)

Kovalev, I. V.; Sidorov, V. G.; Zelenkov, P. V.; Khoroshko, A. Y.; Lelekov, A. T.

2015-10-01

To optimize parameters of beta-electrical converter of isotope Nickel-63 radiation, model of the distribution of EHP generation rate in semiconductor must be derived. By using Monte-Carlo methods in GEANT4 system with ultra-low energy electron physics models this distribution in silicon calculated and approximated with Gauss function. Maximal efficient isotope layer thickness and maximal energy efficiency of EHP generation were estimated.

Readily Available Chiral Benzimidazoles-Derived Guanidines as Organocatalysts in the Asymmetric α-Amination of 1,3-Dicarbonyl Compounds.

PubMed

Benavent, Llorenç; Puccetti, Francesco; Baeza, Alejandro; Gómez-Martínez, Melania

2017-08-11

The synthesis and the evaluation as organocatalysts of new chiral guanidines derived from benzimidazoles in the enantioselective α-amination of 1,3-dicarbonyl compounds using di- t -butylazodicarboxylate as aminating agent is herein disclosed. The catalysts are readily synthesized through the reaction of 2-chlorobezimidazole and a chiral amine in moderate-to-good yields. Among all of them, those derived from ( R )-1-phenylethan-1-amine ( 1 ) and ( S )-1-(2-naphthyl)ethan-1-amine ( 3 ) turned out to be the most efficient for such asymmetric transformation, rendering good-to-high yields and moderate-to-good enantioselectivities for the amination products.

Arylation, alkenylation, and alkylation of 2-halopyridine N-oxides with grignard reagents: a solution to the problem of C2/C6 regioselective functionalization of pyridine derivatives.

PubMed

Zhang, Song; Liao, Lian-Yan; Zhang, Fang; Duan, Xin-Fang

2013-03-15

A facile arylation, alkenylation, and alkylation of functionalized 2-halopyridine N-oxides with various Grignard reagents was developed. It represented a highly efficient and selective C-H bond functionalization of pyridine derivatives in the presence of reactive C-Cl or C-Br bonds. Using Cl or Br as a blocking group, C2/C6 site-controllable functionalization of pyridine derivatives has been achieved. Various pyridine compounds can be prepared as illustrated in the total syntheses of Onychine, dielsine, and PARP-1 inhibitor GPI 16539.

Signal processing using sparse derivatives with applications to chromatograms and ECG

NASA Astrophysics Data System (ADS)

Ning, Xiaoran

In this thesis, we investigate the sparsity exist in the derivative domain. Particularly, we focus on the type of signals which posses up to Mth (M > 0) order sparse derivatives. Efforts are put on formulating proper penalty functions and optimization problems to capture properties related to sparse derivatives, searching for fast, computationally efficient solvers. Also the effectiveness of these algorithms are applied to two real world applications. In the first application, we provide an algorithm which jointly addresses the problems of chromatogram baseline correction and noise reduction. The series of chromatogram peaks are modeled as sparse with sparse derivatives, and the baseline is modeled as a low-pass signal. A convex optimization problem is formulated so as to encapsulate these non-parametric models. To account for the positivity of chromatogram peaks, an asymmetric penalty function is also utilized with symmetric penalty functions. A robust, computationally efficient, iterative algorithm is developed that is guaranteed to converge to the unique optimal solution. The approach, termed Baseline Estimation And Denoising with Sparsity (BEADS), is evaluated and compared with two state-of-the-art methods using both simulated and real chromatogram data. Promising result is obtained. In the second application, a novel Electrocardiography (ECG) enhancement algorithm is designed also based on sparse derivatives. In the real medical environment, ECG signals are often contaminated by various kinds of noise or artifacts, for example, morphological changes due to motion artifact, non-stationary noise due to muscular contraction (EMG), etc. Some of these contaminations severely affect the usefulness of ECG signals, especially when computer aided algorithms are utilized. By solving the proposed convex l1 optimization problem, artifacts are reduced by modeling the clean ECG signal as a sum of two signals whose second and third-order derivatives (differences) are sparse respectively. At the end, the algorithm is applied to a QRS detection system and validated using the MIT-BIH Arrhythmia database (109452 anotations), resulting a sensitivity of Se = 99.87%$ and a positive prediction of +P = 99.88%.

Variational Methods in Design Optimization and Sensitivity Analysis for Two-Dimensional Euler Equations

NASA Technical Reports Server (NTRS)

Ibrahim, A. H.; Tiwari, S. N.; Smith, R. E.

1997-01-01

Variational methods (VM) sensitivity analysis employed to derive the costate (adjoint) equations, the transversality conditions, and the functional sensitivity derivatives. In the derivation of the sensitivity equations, the variational methods use the generalized calculus of variations, in which the variable boundary is considered as the design function. The converged solution of the state equations together with the converged solution of the costate equations are integrated along the domain boundary to uniquely determine the functional sensitivity derivatives with respect to the design function. The application of the variational methods to aerodynamic shape optimization problems is demonstrated for internal flow problems at supersonic Mach number range. The study shows, that while maintaining the accuracy of the functional sensitivity derivatives within the reasonable range for engineering prediction purposes, the variational methods show a substantial gain in computational efficiency, i.e., computer time and memory, when compared with the finite difference sensitivity analysis.

Semi-automatic system for ultrasonic measurement of texture

DOEpatents

Thompson, R. Bruce; Wormley, Samuel J.

1991-09-17

A means and method for ultrasonic measurement of texture non-destructively and efficiently. Texture characteristics are derived by transmitting ultrasound energy into the material, measuring the time it takes to be received by ultrasound receiving means, and calculating velocity of the ultrasound energy from the timed measurements. Textured characteristics can then be derived from the velocity calculations. One or more sets of ultrasound transmitters and receivers are utilized to derive velocity measurements in different angular orientations through the material and in different ultrasound modes. An ultrasound transmitter is utilized to direct ultrasound energy to the material and one or more ultrasound receivers are utilized to receive the same. The receivers are at a predetermined fixed distance from the transmitter. A control means is utilized to control transmission of the ultrasound, and a processing means derives timing, calculation of velocity and derivation of texture characteristics.

Semi-automatic system for ultrasonic measurement of texture

DOEpatents

Thompson, R.B.; Wormley, S.J.

1991-09-17

A means and method are disclosed for ultrasonic measurement of texture nondestructively and efficiently. Texture characteristics are derived by transmitting ultrasound energy into the material, measuring the time it takes to be received by ultrasound receiving means, and calculating velocity of the ultrasound energy from the timed measurements. Textured characteristics can then be derived from the velocity calculations. One or more sets of ultrasound transmitters and receivers are utilized to derive velocity measurements in different angular orientations through the material and in different ultrasound modes. An ultrasound transmitter is utilized to direct ultrasound energy to the material and one or more ultrasound receivers are utilized to receive the same. The receivers are at a predetermined fixed distance from the transmitter. A control means is utilized to control transmission of the ultrasound, and a processing means derives timing, calculation of velocity and derivation of texture characteristics. 5 figures.

Complete active space configuration interaction from state-averaged configuration interaction singles natural orbitals: Analytic first derivatives and derivative coupling vectors

NASA Astrophysics Data System (ADS)

Fales, B. Scott; Shu, Yinan; Levine, Benjamin G.; Hohenstein, Edward G.

2017-09-01

A new complete active space configuration interaction (CASCI) method was recently introduced that uses state-averaged natural orbitals from the configuration interaction singles method (configuration interaction singles natural orbital CASCI, CISNO-CASCI). This method has been shown to perform as well or better than state-averaged complete active space self-consistent field for a variety of systems. However, further development and testing of this method have been limited by the lack of available analytic first derivatives of the CISNO-CASCI energy as well as the derivative coupling between electronic states. In the present work, we present a Lagrangian-based formulation of these derivatives as well as a highly efficient implementation of the resulting equations accelerated with graphical processing units. We demonstrate that the CISNO-CASCI method is practical for dynamical simulations of photochemical processes in molecular systems containing hundreds of atoms.

Complete active space configuration interaction from state-averaged configuration interaction singles natural orbitals: Analytic first derivatives and derivative coupling vectors.

PubMed

Fales, B Scott; Shu, Yinan; Levine, Benjamin G; Hohenstein, Edward G

2017-09-07

A new complete active space configuration interaction (CASCI) method was recently introduced that uses state-averaged natural orbitals from the configuration interaction singles method (configuration interaction singles natural orbital CASCI, CISNO-CASCI). This method has been shown to perform as well or better than state-averaged complete active space self-consistent field for a variety of systems. However, further development and testing of this method have been limited by the lack of available analytic first derivatives of the CISNO-CASCI energy as well as the derivative coupling between electronic states. In the present work, we present a Lagrangian-based formulation of these derivatives as well as a highly efficient implementation of the resulting equations accelerated with graphical processing units. We demonstrate that the CISNO-CASCI method is practical for dynamical simulations of photochemical processes in molecular systems containing hundreds of atoms.

A new class of sulfoxide surfactants derived from Tris. Synthesis and preliminary assessments of their properties.

PubMed

Barthélémy, P; Maurizis, J C; Lacombe, J M; Pucci, B

1998-06-16

A new class of non-ionic amphiphilic molecules suitable for biological purposes, especially extraction of membrane proteins, is reported. Such surfactants were prepared in two steps: addition of alkyl or fluoroalkyl mercaptan on Tris(hydroxymethyl)acrylamidomethane (THAM) derivatives, followed by the oxydation of sulfide group in sulfoxide moiety in order to provide water solubility to the molecule. The detergent efficiency of these new surfactants were assayed on rat liver cells.

Exact least squares adaptive beamforming using an orthogonalization network

NASA Astrophysics Data System (ADS)

Yuen, Stanley M.

1991-03-01

The pros and cons of various classical and state-of-the-art methods in adaptive array processing are discussed, and the relevant concepts and historical developments are pointed out. A set of easy-to-understand equations for facilitating derivation of any least-squares-based algorithm is derived. Using this set of equations and incorporating all of the useful properties associated with various techniques, an efficient solution to the real-time adaptive beamforming problem is developed.

Continuous-flow retro-Diels-Alder reaction: an efficient method for the preparation of pyrimidinone derivatives.

PubMed

Nekkaa, Imane; Palkó, Márta; Mándity, István M; Fülöp, Ferenc

2018-01-01

The syntheses of various pyrimidinones as potentially bioactive products by means of the highly controlled continuous-flow retro-Diels-Alder reaction of condensed pyrimidinone derivatives are presented. Noteworthy, the use of this approach allowed us to rapidly screen a selection of conditions and quickly confirm the viability of preparing the desired pyrimidinones in short reaction times. Yields typically higher than those published earlier using conventional batch or microwave processes were achieved.

Synthesis of Cyano-Containing Phenanthridine Derivatives via Catalyst-, Base-, and Oxidant-Free Direct Cyanoalkylarylation of Isocyanides.

PubMed

Song, Weihong; Yan, Peipei; Shen, Dan; Chen, Zhangtao; Zeng, Xiaofei; Zhong, Guofu

2017-04-21

An efficient catalyst-, base-, and oxidant-free direct cyanoalkylarylation of isocyanides with AIBN has been developed under mild conditions. This strategy provides an elusive and rapid access to a wide range of cyano-containing phenanthridine derivatives in good yields via a one-pot alkylation/cyclization radical-cascade process. The mild reaction conditions together with no need of any catalyst, base, or oxidant make this protocol environmentally benign and practical.

Tailored Recovery of Carbons from Waste Tires for Enhanced Performance as Anodes in Lithium-ion Batteries

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

Naskar, Amit K; Bi,; Saha, Dipendu

2014-01-01

Morphologically tailored pyrolysis-recovered carbon black is utilized in lithium-ion batteries as a potential solution for adding value to waste tire-rubber-derived materials. Micronized tire rubber was digested in a hot oleum bath to yield a sulfonated rubber slurry that was then filtered, washed, and compressed into a solid cake. Carbon was recovered from the modified rubber cake by pyrolysis in a nitrogen atmosphere. The chemical pretreatment of rubber produced a carbon monolith with higher yield than that from the control (a fluffy tire-rubber-derived carbon black). The carbon monolith showed a very small volume fraction of pores of widths 3 4 nm,more » reduced specific surface area, and an ordered assembly of graphitic domains. Electrochemical studies on the recovered-carbon-based anode revealed an improved Li-ion battery performance with higher reversible capacity than that of commercial carbon materials. Anodes made with a sulfonated tire-rubber-derived carbon and a control tire-rubber-derived carbon, respectively, exhibited an initial coulombic efficiency of 80% and 45%, respectively. The reversible capacity of the cell with the sulfonated carbon as anode was 400 mAh/g after 100 cycles, with nearly 100% coulombic efficiency. Our success in producing higher performance carbon material from waste tire rubber for potential use in energy storage applications adds a new avenue to tire rubber recycling.« less

Cryopreservation of embryonic stem cell-derived multicellular neural aggregates labeled with micron-sized particles of iron oxide for magnetic resonance imaging.

PubMed

Yan, Yuanwei; Sart, Sébastien; Calixto Bejarano, Fabian; Muroski, Megan E; Strouse, Geoffrey F; Grant, Samuel C; Li, Yan

2015-01-01

Magnetic resonance imaging (MRI) provides an effective approach to track labeled pluripotent stem cell (PSC)-derived neural progenitor cells (NPCs) for neurological disorder treatments after cell labeling with a contrast agent, such as an iron oxide derivative. Cryopreservation of pre-labeled neural cells, especially in three-dimensional (3D) structure, can provide a uniform cell population and preserve the stem cell niche for the subsequent applications. In this study, the effects of cryopreservation on PSC-derived multicellular NPC aggregates labeled with micron-sized particles of iron oxide (MPIO) were investigated. These NPC aggregates were labeled prior to cryopreservation because labeling thawed cells can be limited by inefficient intracellular uptake, variations in labeling efficiency, and increased culture time before use, minimizing their translation to clinical settings. The results indicated that intracellular MPIO incorporation was retained after cryopreservation (70-80% labeling efficiency), and MPIO labeling had little adverse effects on cell recovery, proliferation, cytotoxicity and neural lineage commitment post-cryopreservation. MRI analysis showed comparable detectability for the MPIO-labeled cells before and after cryopreservation indicated by T2 and T2* relaxation rates. Cryopreserving MPIO-labeled 3D multicellular NPC aggregates can be applied in in vivo cell tracking studies and lead to more rapid translation from preservation to clinical implementation. © 2015 American Institute of Chemical Engineers.

Hydrogen Bond Acceptors and Additional Cationic Charges in Methylene Blue Derivatives: Photophysics and Antimicrobial Efficiency

PubMed Central

Felgenträger, Ariane; Maisch, Tim; Dobler, Daniel; Späth, Andreas

2013-01-01

Photodynamic inactivation of bacteria (PIB) by efficient singlet oxygen photosensitizers might be a beneficial alternative to antibiotics in the struggle against multiresistant bacteria. Phenothiazinium dyes belong to the most prominent classes of such sensitizers due to their intense absorption in the red-light region (λ abs, max ca. 600–680 nm, ε > 50000 L mol−1 cm−1), their low toxicity, and their attachment/penetration abilities. Except simple substituents like alkyl or hydroxyalkyl residues, nearly no modifications of the phenothiaziniums have been pursued at the auxochromic sites. By this, the properties of methylene blue derivatives and their fields of application are limited; it remains unclear if their potential antimicrobial efficacy may be enhanced, also to compete with porphyrins. We prepared a set of six mainly novel methylene blue derivatives with the ability of additional hydrogen bonding and/or additional cationic charges to study the substituents' effect on their activity/toxicity profiles and photophysical properties. Direct detection of singlet oxygen was performed at 1270 nm and the singlet oxygen quantum yields were determined. In suspensions with both, Gram-positive and Gram-negative bacteria, some derivatives were highly active upon illumination to inactivate S. aureus and E. coli up to 7 log10 steps (99.99999%) without inherent toxicities in the nonirradiated state. PMID:23509728

Molecular approaches towards development of purified natural products and their structurally known derivatives as efficient anti-cancer drugs: current trends.

PubMed

Saha, Santu Kumar; Khuda-Bukhsh, Anisur Rahman

2013-08-15

Several natural products and their derivatives, either in purified or structurally identified form, exhibit immense pharmacological and biological properties, some of them showing considerable anticancer potential. Although the molecular mechanisms of action of some of these products are yet to be elucidated, extensive research in this area continues to generate new data that are clinically exploitable. Recent advancement in molecular biology, high throughput screening, biomarker identifications, target selection and genomic approaches have enabled us to understand salient interactions of natural products and their derivatives with cancer cells vis-à-vis normal cells. In this review we highlight the recent approaches and application of innovative technologies made to improve quality as well as efficiency of structurally identified natural products and their derivatives, particularly in small molecular forms capable of being used in "targeted therapies" in oncology. These products preferentially involve multiple mechanistic pathways and overcome chemo-resistance in tumor types with cumulative action. We also mention briefly a few physico-chemical features that compare natural products with drugs in recent natural product discovery approaches. We further report here a few purified natural products as examples that provide molecular interventions in cancer therapeutics to give the reader a glimpse of the current trends of approach for discovering useful anticancer drugs. © 2013 Elsevier B.V. All rights reserved.

Rhodium Catalyzed Intramolecular C-H Insertion of α-Aryl-α-diazo Ketones

PubMed Central

Taber, Douglass F.; Tian, Weiwei

2011-01-01

Direct diazo transfer proceeds smoothly with α-aryl ketones. The derived α-aryl-α-diazo ketones cyclize efficiently with Rh catalysis to give the corresponding α-aryl cyclopentanones. PMID:17385917

First-Order Altitude Effects on the Cruise Efficiency of Subsonic Transport Aircraft

NASA Technical Reports Server (NTRS)

Guynn, Mark D.

2011-01-01

Aircraft fuel efficiency is a function of many different parameters, including characteristics of the engines, characteristics of the airframe, and the conditions under which the aircraft is operated. For a given vehicle, the airframe and engine characteristics are for the most part fixed quantities and efficiency is primarily a function of operational conditions. One important influence on cruise efficiency is cruise altitude. Various future scenarios have been postulated for cruise altitude, from the freedom to fly at optimum altitudes to altitude restrictions imposed for environmental reasons. This report provides background on the fundamental relationships determining aircraft cruise efficiency and examines the sensitivity of efficiency to cruise altitude. Analytical models of two current aircraft designs are used to derive quantitative results. Efficiency penalties are found to be generally less than 1% when within roughly 2000 ft of the optimum cruise altitude. Even the restrictive scenario of constant altitude cruise is found to result in a modest fuel consumption penalty if the fixed altitude is in an appropriate range.

Optimal Energy Efficiency Fairness of Nodes in Wireless Powered Communication Networks.

PubMed

Zhang, Jing; Zhou, Qingjie; Ng, Derrick Wing Kwan; Jo, Minho

2017-09-15

In wireless powered communication networks (WPCNs), it is essential to research energy efficiency fairness in order to evaluate the balance of nodes for receiving information and harvesting energy. In this paper, we propose an efficient iterative algorithm for optimal energy efficiency proportional fairness in WPCN. The main idea is to use stochastic geometry to derive the mean proportionally fairness utility function with respect to user association probability and receive threshold. Subsequently, we prove that the relaxed proportionally fairness utility function is a concave function for user association probability and receive threshold, respectively. At the same time, a sub-optimal algorithm by exploiting alternating optimization approach is proposed. Through numerical simulations, we demonstrate that our sub-optimal algorithm can obtain a result close to optimal energy efficiency proportional fairness with significant reduction of computational complexity.

Optimal Energy Efficiency Fairness of Nodes in Wireless Powered Communication Networks

PubMed Central

Zhou, Qingjie; Ng, Derrick Wing Kwan; Jo, Minho

2017-01-01

In wireless powered communication networks (WPCNs), it is essential to research energy efficiency fairness in order to evaluate the balance of nodes for receiving information and harvesting energy. In this paper, we propose an efficient iterative algorithm for optimal energy efficiency proportional fairness in WPCN. The main idea is to use stochastic geometry to derive the mean proportionally fairness utility function with respect to user association probability and receive threshold. Subsequently, we prove that the relaxed proportionally fairness utility function is a concave function for user association probability and receive threshold, respectively. At the same time, a sub-optimal algorithm by exploiting alternating optimization approach is proposed. Through numerical simulations, we demonstrate that our sub-optimal algorithm can obtain a result close to optimal energy efficiency proportional fairness with significant reduction of computational complexity. PMID:28914818

A study on technical efficiency of a DMU (review of literature)

NASA Astrophysics Data System (ADS)

Venkateswarlu, B.; Mahaboob, B.; Subbarami Reddy, C.; Sankar, J. Ravi

2017-11-01

In this research paper the concept of technical efficiency (due to Farell) [1] of a decision making unit (DMU) has been introduced and the measure of technical and cost efficiencies are derived. Timmer’s [2] deterministic approach to estimate the Cobb-Douglas production frontier has been proposed. The idea of extension of Timmer’s [2] method to any production frontier which is linear in parameters has been presented here. The estimation of parameters of Cobb-Douglas production frontier by linear programming approach has been discussed in this paper. Mark et al. [3] proposed a non-parametric method to assess efficiency. Nuti et al. [4] investigated the relationships among technical efficiency scores, weighted per capita cost and overall performance Gahe Zing Samuel Yank et al. [5] used Data envelopment analysis to assess technical assessment in banking sectors.

Self-assembly of gibberellic amide assemblies and their applications in the growth and fabrication of ordered gold nanoparticles

NASA Astrophysics Data System (ADS)

Smoak, Evan M.; Carlo, Andrew D.; Fowles, Catherine C.; Banerjee, Ipsita A.

2010-01-01

Gibberellins are a group of naturally occurring diterpenoid based phytohormones that play a vital role in plant growth and development. In this work, we have studied the self-assembly of gibberellic acid, a phytohormone, which belongs to the family of gibberellins, and designed amide derivatives of gibberellic acid (GA3) for the facile, green synthesis of gold nanoparticles. It was found that the derivatives self-assembled into nanofibers and nanoribbons in aqueous solutions at varying pH. Further, upon incubation with tetrachloroaurate, the self-assembled GA3-amide derivatives efficiently nucleated and formed gold nanoparticles when heated to 60 °C. Energy dispersive x-ray spectroscopy, transmission electron microscopy and scanning electron microscopy analyses revealed that uniform coatings of gold nanoparticles in the 10-20 nm range were obtained at low pH on the nanowire surfaces without the assistance of additional reducing agents. This simple method for the development of morphology controlled gold nanoparticles using a plant hormone derivative opens doors for a new class of plant biomaterials which can efficiently yield gold nanoparticles in an environmentally friendly manner. The gold encrusted nanowires formed using biomimetic methods may lead on to the formation of conductive nanowires, which may be useful for a wide range of applications such as in optoelectronics and sensors. Further, the spontaneous formation of highly organized nanostructures obtained from plant phytohormone derivatives such as gibberellic acid is of particular interest as it might help in further understanding the supramolecular assembly mechanism of more highly organized biological structures.

Mesenchymal stem cells-derived exosomes are more immunosuppressive than microparticles in inflammatory arthritis

PubMed Central

Cosenza, Stella; Toupet, Karine; Maumus, Marie; Luz-Crawford, Patricia; Blanc-Brude, Olivier; Jorgensen, Christian; Noël, Danièle

2018-01-01

Objectives: Mesenchymal stem cells (MSCs) release extracellular vesicles (EVs) that display a therapeutic effect in inflammatory disease models. Although MSCs can prevent arthritis, the role of MSCs-derived EVs has never been reported in rheumatoid arthritis. This prompted us to compare the function of exosomes (Exos) and microparticles (MPs) isolated from MSCs and investigate their immunomodulatory function in arthritis. Methods: MSCs-derived Exos and MPs were isolated by differential ultracentrifugation. Immunosuppressive effects of MPs or Exos were investigated on T and B lymphocytes in vitro and in the Delayed-Type Hypersensitivity (DTH) and Collagen-Induced Arthritis (CIA) models. Results: Exos and MPs from MSCs inhibited T lymphocyte proliferation in a dose-dependent manner and decreased the percentage of CD4+ and CD8+ T cell subsets. Interestingly, Exos increased Treg cell populations while parental MSCs did not. Conversely, plasmablast differentiation was reduced to a similar extent by MSCs, Exos or MPs. IFN-γ priming of MSCs before vesicles isolation did not influence the immunomodulatory function of isolated Exos or MPs. In DTH, we observed a dose-dependent anti-inflammatory effect of MPs and Exos, while in the CIA model, Exos efficiently decreased clinical signs of inflammation. The beneficial effect of Exos was associated with fewer plasmablasts and more Breg-like cells in lymph nodes. Conclusions: Both MSCs-derived MPs and Exos exerted an anti-inflammatory role on T and B lymphocytes independently of MSCs priming. However, Exos were more efficient in suppressing inflammation in vivo. Our work is the first demonstration of the therapeutic potential of MSCs-derived EVs in inflammatory arthritis. PMID:29507629

RE12 derivatives displaying Vaccinia H1-related phosphatase (VHR) inhibition in the presence of detergent and their anti-proliferative activity against HeLa cells.

PubMed

Thuaud, Frédéric; Kojima, Shuntaro; Hirai, Go; Oonuma, Kana; Tsuchiya, Ayako; Uchida, Takako; Tsuchimoto, Teruhisa; Sodeoka, Mikiko

2014-05-01

New derivatives of Vaccinia H1-related phosphatase (VHR) inhibitor RE12 (5) were designed by replacing the long straight alkyl chain with other hydrophobic functionalities containing two aromatic rings, with the aim of obtaining potent, cell-active inhibitors. We established a direct coupling reaction between tetronic acid derivative and thioimidate to prepare the RE derivatives 6a-6i efficiently. These compounds all showed VHR-inhibitory activity in the presence of 0.001% NP-40, whereas RE12 (5) was inactive under this condition, even at 100 μM. Further structure-activity studies focused on terminal substitution afforded trifluoromethyl derivative 6k (RE176) and nitro derivative 6l (RE177). The IC50 value of 6l in the presence of NP-40 was almost equivalent to that of RE12 (5) in its absence. Compound 6k (RE176) potently inhibited proliferation of HeLa cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chitosan derivatives targeting lipid bilayers: Synthesis, biological activity and interaction with model membranes.

PubMed

Martins, Danubia Batista; Nasário, Fábio Domingues; Silva-Gonçalves, Laiz Costa; de Oliveira Tiera, Vera Aparecida; Arcisio-Miranda, Manoel; Tiera, Marcio José; Dos Santos Cabrera, Marcia Perez

2018-02-01

The antimicrobial activity of chitosan and derivatives to human and plant pathogens represents a high-valued prospective market. Presently, two low molecular weight derivatives, endowed with hydrophobic and cationic character at different ratios were synthesized and characterized. They exhibit antimicrobial activity and increased performance in relation to the intermediate and starting compounds. However, just the derivative with higher cationic character showed cytotoxicity towards human cervical carcinoma cells. Considering cell membranes as targets, the mode of action was investigated through the interaction with model lipid vesicles mimicking bacterial, tumoral and erythrocyte membranes. Intense lytic activity and binding are demonstrated for both derivatives in anionic bilayers. The less charged compound exhibits slightly improved selectivity towards bacterial model membranes, suggesting that balancing its hydrophobic/hydrophilic character may improve efficiency. Observing the aggregation of vesicles, we hypothesize that the "charge cluster mechanism", ascribed to some antimicrobial peptides, could be applied to these chitosan derivatives. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Li, Xinle

In conclusion, we have for the first time developed a novel solid base catalyst, Ndoped MOF-253 derived porous carbons (Cz-MOF-253). Cz-MOF-253 is highly porous and exhibit high efficiency in Knoevenagel condensation reaction. Furthermore, Cz-MOF-253 is robust and can be reused up to five times. In comparison, the analogous nitrogen-free catalyst-Cz-DUT-5, and other nitrogen- MOFs derived carbon showed an inferior performance. Moreover, the high basicity and porous nature enable the design of bifunctional catalyst and facilitate tandem condensation-hydrogenation reactions. This work delineates the first attempt that demonstrates MOF-derived carbons as solid base catalyst and its potential application in tandem catalysis. Futuremore » work on exploring new catalytic reactions based on such porous Lewis basic MOF-derived carbons is currently underway.« less

Complexation of triptycene-derived macrotricyclic polyether with paraquat derivatives, diquat, and a 2,7-diazapyrenium salt: guest-induced conformational changes of the host.

PubMed

Han, Ying; Cao, Jing; Li, Peng-Fei; Zong, Qian-Shou; Zhao, Jian-Min; Guo, Jia-Bin; Xiang, Jun-Feng; Chen, Chuan-Feng

2013-04-05

Complexation between a triptycene-derived macrotricyclic polyether containing two dibenzo-[30]-crown-10 cavities and different functionalized paraquat derivatives, diquat, and a 2,7-diazapyrenium salt in both solution and solid state was investigated in detail. It was found that depending on the guests with different terminal functional groups and structures, the macrotricyclic polyether could form 1:1 or 1:2 complexes with the guests in different complexation modes in solution and also in the solid state. Especially, the conformation of the macrotricyclic polyether was efficiently adjusted by the encapsulated guests, which was to some extent similar to substrate-induced fit of enzymes. Moreover, the binding and releasing of the guests in the complexes could be controlled by potassium ions.

Marine Fish Proteins and Peptides for Cosmeceuticals: A Review

PubMed Central

Venkatesan, Jayachandran; Anil, Sukumaran; Kim, Se-Kwon; Shim, Min Suk

2017-01-01

Marine fish provide a rich source of bioactive compounds such as proteins and peptides. The bioactive proteins and peptides derived from marine fish have gained enormous interest in nutraceutical, pharmaceutical, and cosmeceutical industries due to their broad spectrum of bioactivities, including antioxidant, antimicrobial, and anti-aging activities. Recently, the development of cosmeceuticals using marine fish-derived proteins and peptides obtained from chemical or enzymatical hydrolysis of fish processing by-products has increased rapidly owing to their activities in antioxidation and tissue regeneration. Marine fish-derived collagen has been utilized for the development of cosmeceutical products due to its abilities in skin repair and tissue regeneration. Marine fish-derived peptides have also been utilized for various cosmeceutical applications due to their antioxidant, antimicrobial, and matrix metalloproteinase inhibitory activities. In addition, marine fish-derived proteins and hydrolysates demonstrated efficient anti-photoaging activity. The present review highlights and presents an overview of the current status of the isolation and applications of marine fish-derived proteins and peptides. This review also demonstrates that marine fish-derived proteins and peptides have high potential for biocompatible and effective cosmeceuticals. PMID:28524092

Diffractive variable beam splitter: optimal design.

PubMed

Borghi, R; Cincotti, G; Santarsiero, M

2000-01-01

The analytical expression of the phase profile of the optimum diffractive beam splitter with an arbitrary power ratio between the two output beams is derived. The phase function is obtained by an analytical optimization procedure such that the diffraction efficiency of the resulting optical element is the highest for an actual device. Comparisons are presented with the efficiency of a diffractive beam splitter specified by a sawtooth phase function and with the pertinent theoretical upper bound for this type of element.

Application of selected advanced technologies to high performance, single-engine, business airplanes

NASA Technical Reports Server (NTRS)

Domack, C. S.; Martin, G. L.

1984-01-01

Improvements in performance and fuel efficiency are evaluated for five new configurations of a six place, single turboprop, business airplane derived from a conventional, aluminum construction baseline aircraft. Results show the greatest performance gains for enhancements in natural laminar flow. A conceptual diesel engine provides greater fuel efficiency but reduced performance. Less significant effects are produced by the utilization of composite materials construction or by reconfiguration from tractor to pusher propeller installation.

Organocatalytic Upgrading of Furfural and 5-Hydroxymethyl Furfural to C10 and C12 Furoins with Quantitative Yield and Atom-Efficiency

PubMed Central

Zang, Hongjun; Chen, Eugene Y. X.

2015-01-01

There is increasing interest in the upgrading of C5 furfural (FF) and C6 5-hydroxymethyl furfural (HMF) into C10 and C12 furoins as higher energy-density intermediates for renewable chemicals, materials, and biofuels. This work utilizes the organocatalytic approach, using the in situ generated N,S-heterocyclic carbene catalyst derived from thiazolium ionic liquids (ILs), to achieve highly efficient self-coupling reactions of FF and HMF. Specifically, variations of the thiazolium IL structure have led to the most active and efficient catalyst system of the current series, which is derived from a new thiazolium IL carrying the electron-donating acetate group at the 5-ring position. For FF coupling by this IL (0.1 mol %, 60 °C, 1 h), when combined with Et3N, furoin was obtained in >99% yield. A 97% yield of the C12 furoin was also achieved from the HMF coupling by this catalyst system (10 mol % loading, 120 °C, 3 h). On the other hand, the thiazolium IL bearing the electron-withdrawing group at the 5-ring position is the least active and efficient catalyst. The mechanistic aspects of the coupling reaction by the thiazolium catalyst system have also been examined and a mechanism has been proposed. PMID:25830482

Constrained Total Generalized p-Variation Minimization for Few-View X-Ray Computed Tomography Image Reconstruction

PubMed Central

Zhang, Hanming; Wang, Linyuan; Yan, Bin; Li, Lei; Cai, Ailong; Hu, Guoen

2016-01-01

Total generalized variation (TGV)-based computed tomography (CT) image reconstruction, which utilizes high-order image derivatives, is superior to total variation-based methods in terms of the preservation of edge information and the suppression of unfavorable staircase effects. However, conventional TGV regularization employs l1-based form, which is not the most direct method for maximizing sparsity prior. In this study, we propose a total generalized p-variation (TGpV) regularization model to improve the sparsity exploitation of TGV and offer efficient solutions to few-view CT image reconstruction problems. To solve the nonconvex optimization problem of the TGpV minimization model, we then present an efficient iterative algorithm based on the alternating minimization of augmented Lagrangian function. All of the resulting subproblems decoupled by variable splitting admit explicit solutions by applying alternating minimization method and generalized p-shrinkage mapping. In addition, approximate solutions that can be easily performed and quickly calculated through fast Fourier transform are derived using the proximal point method to reduce the cost of inner subproblems. The accuracy and efficiency of the simulated and real data are qualitatively and quantitatively evaluated to validate the efficiency and feasibility of the proposed method. Overall, the proposed method exhibits reasonable performance and outperforms the original TGV-based method when applied to few-view problems. PMID:26901410

Improved hematopoietic differentiation efficiency of gene-corrected beta-thalassemia induced pluripotent stem cells by CRISPR/Cas9 system.

PubMed

Song, Bing; Fan, Yong; He, Wenyin; Zhu, Detu; Niu, Xiaohua; Wang, Ding; Ou, Zhanhui; Luo, Min; Sun, Xiaofang

2015-05-01

The generation of beta-thalassemia (β-Thal) patient-specific induced pluripotent stem cells (iPSCs), subsequent homologous recombination-based gene correction of disease-causing mutations/deletions in the β-globin gene (HBB), and their derived hematopoietic stem cell (HSC) transplantation offers an ideal therapeutic solution for treating this disease. However, the hematopoietic differentiation efficiency of gene-corrected β-Thal iPSCs has not been well evaluated in the previous studies. In this study, we used the latest gene-editing tool, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9), to correct β-Thal iPSCs; gene-corrected cells exhibit normal karyotypes and full pluripotency as human embryonic stem cells (hESCs) showed no off-targeting effects. Then, we evaluated the differentiation efficiency of the gene-corrected β-Thal iPSCs. We found that during hematopoietic differentiation, gene-corrected β-Thal iPSCs showed an increased embryoid body ratio and various hematopoietic progenitor cell percentages. More importantly, the gene-corrected β-Thal iPSC lines restored HBB expression and reduced reactive oxygen species production compared with the uncorrected group. Our study suggested that hematopoietic differentiation efficiency of β-Thal iPSCs was greatly improved once corrected by the CRISPR/Cas9 system, and the information gained from our study would greatly promote the clinical application of β-Thal iPSC-derived HSCs in transplantation.

The mechanics of locomotion in the squid Loligo pealei: locomotory function and unsteady hydrodynamics of the jet and intramantle pressure.

PubMed

Anderson, E J; DeMont, M E

2000-09-01

High-speed, high-resolution digital video recordings of swimming squid (Loligo pealei) were acquired. These recordings were used to determine very accurate swimming kinematics, body deformations and mantle cavity volume. The time-varying squid profile was digitized automatically from the acquired swimming sequences. Mantle cavity volume flow rates were determined under the assumption of axisymmetry and the condition of incompressibility. The data were then used to calculate jet velocity, jet thrust and intramantle pressure, including unsteady effects. Because of the accurate measurements of volume flow rate, the standard use of estimated discharge coefficients was avoided. Equations for jet and whole-cycle propulsive efficiency were developed, including a general equation incorporating unsteady effects. Squid were observed to eject up to 94 % of their intramantle working fluid at relatively high swimming speeds. As a result, the standard use of the so-called large-reservoir approximation in the determination of intramantle pressure by the Bernoulli equation leads to significant errors in calculating intramantle pressure from jet velocity and vice versa. The failure of this approximation in squid locomotion also implies that pressure variation throughout the mantle cannot be ignored. In addition, the unsteady terms of the Bernoulli equation and the momentum equation proved to be significant to the determination of intramantle pressure and jet thrust. Equations of propulsive efficiency derived for squid did not resemble Froude efficiency. Instead, they resembled the equation of rocket motor propulsive efficiency. The Froude equation was found to underestimate the propulsive efficiency of the jet period of the squid locomotory cycle and to overestimate whole-cycle propulsive efficiency when compared with efficiencies calculated from equations derived with the squid locomotory apparatus in mind. The equations for squid propulsive efficiency reveal that the refill period of squid plays a greater role, and the jet period a lesser role, in the low whole-cycle efficiencies predicted in squid and similar jet-propelled organisms. These findings offer new perspectives on locomotory hydrodynamics, intramantle pressure measurements and functional morphology with regard to squid and other jet-propelled organisms.

Discovery of CREBBP Bromodomain Inhibitors by High-Throughput Docking and Hit Optimization Guided by Molecular Dynamics.

PubMed

Xu, Min; Unzue, Andrea; Dong, Jing; Spiliotopoulos, Dimitrios; Nevado, Cristina; Caflisch, Amedeo

2016-02-25

We have identified two chemotypes of CREBBP bromodomain ligands by fragment-based high-throughput docking. Only 17 molecules from the original library of two-million compounds were tested in vitro. Optimization of the two low-micromolar hits, the 4-acylpyrrole 1 and acylbenzene 9, was driven by molecular dynamics results which suggested improvement of the polar interactions with the Arg1173 side chain at the rim of the binding site. The synthesis of only two derivatives of 1 yielded the 4-acylpyrrole 6 which shows a single-digit micromolar affinity for the CREBBP bromodomain and a ligand efficiency of 0.34 kcal/mol per non-hydrogen atom. Optimization of the acylbenzene hit 9 resulted in a series of derivatives with nanomolar potencies, good ligand efficiency and selectivity (see Unzue, A.; Xu, M.; Dong, J.; Wiedmer, L.; Spiliotopoulos, D.; Caflisch, A.; Nevado, C.Fragment-Based Design of Selective Nanomolar Ligands of the CREBBP Bromodomain. J. Med. Chem. 2015, DOI: 10.1021/acs.jmedchem.5b00172). The in silico predicted binding mode of the acylbenzene derivative 10 was validated by solving the structure of the complex with the CREBBP bromodomain.

Sustainable Production of o-Xylene from Biomass-Derived Pinacol and Acrolein.

PubMed

Hu, Yancheng; Li, Ning; Li, Guangyi; Wang, Aiqin; Cong, Yu; Wang, Xiaodong; Zhang, Tao

2017-07-21

o-Xylene (OX) is a large-volume commodity chemical that is conventionally produced from fossil fuels. In this study, an efficient and sustainable two-step route is used to produce OX from biomass-derived pinacol and acrolein. In the first step, the phosphotungstic acid (HPW)-catalyzed pinacol dehydration in 1-ethyl-3-methylimidazolium chloride ([emim]Cl) selectively affords 2,3-dimethylbutadiene. The high selectivity of this reaction can be ascribed to the H-bonding interaction between Cl - and the hydroxy group of pinacol. The stabilization of the carbocation intermediate by the surrounding anion Cl - may be another reason for the high selectivity. Notably, the good reusability of the HPW/[emim]Cl system can reduce the waste output and production cost. In the second step, OX is selectively produced by a Diels-Alder reaction of 2,3-dimethylbutadiene and acrolein, followed by a Pd/C-catalyzed decarbonylation/aromatization cascade in a one-pot fashion. The sustainable two-step process efficiently produces renewable OX in 79 % overall yield. Analogously, biomass-derived crotonaldehyde and pinacol can also serve as the feedstocks for the production of 1,2,4-trimethylbenzene. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the use of nonfluorescent dye labeled ligands in FRET-based receptor binding studies.

PubMed

Tahtaoui, Chouaib; Guillier, Fabrice; Klotz, Philippe; Galzi, Jean-Luc; Hibert, Marcel; Ilien, Brigitte

2005-12-01

The efficiency of fluorescence resonance energy transfer (FRET) is dependent upon donor-acceptor proximity and spectral overlap, whether the acceptor partner is fluorescent or not. We report here on the design, synthesis, and characterization of two novel pirenzepine derivatives that were coupled to patent blue VF and pinacyanol dyes. These nonfluorescent compounds, when added to cells stably expressing enhanced green fluorescent protein (EGFP)-fused muscarinic M1 receptors, promote EGFP fluorescence extinction in a time-, concentration-, and atropine-dependent manner. They display nanomolar affinity for the muscarinic receptor, determined using either FRET or classical radioligand binding conditions. We provide evidence that these compounds behave as potent acceptors of energy from excited EGFP with quenching efficiencies comparable to those of analogous fluorescent bodipy or rhodamine red pirenzepine derivatives. The advantages they offer over fluorescent ligands are illustrated and discussed in terms of reliability, sensitivity, and wider applicability of FRET-based receptor binding assays.

Possibility of Exosome-Based Therapeutics and Challenges in Production of Exosomes Eligible for Therapeutic Application.

PubMed

Yamashita, Takuma; Takahashi, Yuki; Takakura, Yoshinobu

2018-01-01

Exosomes are cell-derived vesicles with a diameter 30-120 nm. Exosomes contain endogenous proteins and nucleic acids; delivery of these molecules to exosome-recipient cells causes biological effects. Exosomes derived from some types of cells such as mesenchymal stem cells and dendritic cells have therapeutic potential and may be biocompatible and efficient agents against various disorders such as organ injury. However, there are many challenges for the development of exosome-based therapeutics. In particular, producing exosomal formulations is the major barrier for therapeutic application because of their heterogeneity and low productivity. Development and optimization of producing methods, including methods for isolation and storage of exosome formulations, are required for realizing exosome-based therapeutics. In addition, improvement of therapeutic potential and delivery efficiency of exosomes are important for their therapeutic application. In this review, we summarize current knowledge about therapeutic application of exosomes and discuss some challenges in their successful use.

Synthesis, spectroscopic characterization and a comparative study of the corrosion inhibitive efficiency of an α-aminophosphonate and Schiff base derivatives: Experimental and theoretical investigations

NASA Astrophysics Data System (ADS)

Benbouguerra, Khalissa; Chafaa, Salah; Chafai, Nadjib; Mehri, Mouna; Moumeni, Ouahiba; Hellal, Abdelkader

2018-04-01

New α-aminophosphonate (α-APD) and Schiff base (E-NDPIMA) derivatives have been prepared and their structures ware proved by IR, UV-Vis, 1H, 13C and 31P NMR spectroscopy. Their inhibitive capacities on the XC48 carbon steel corrosion in 0.5 mol L-1 H2SO4 solution were explored by weight loss, Tafel polarization, electrochemical impedance spectroscopy (EIS) and atomic force microscope (AFM). Experimental results illustrate that the synthesized compounds are an effectives inhibitors and the adsorption of inhibitors molecules on the carbon steel surface obeys Langmuir adsorption isotherm. In addition, quantum chemical calculations performed with density function theory (DFT) method have been used to correlate the inhibition efficiency established experimentally. Also, the molecular dynamics simulations have been utilized to simulate the interactions between the inhibitors molecules and Fe (100) surface in aqueous solution.

Work extraction from quantum systems with bounded fluctuations in work.

PubMed

Richens, Jonathan G; Masanes, Lluis

2016-11-25

In the standard framework of thermodynamics, work is a random variable whose average is bounded by the change in free energy of the system. This average work is calculated without regard for the size of its fluctuations. Here we show that for some processes, such as reversible cooling, the fluctuations in work diverge. Realistic thermal machines may be unable to cope with arbitrarily large fluctuations. Hence, it is important to understand how thermodynamic efficiency rates are modified by bounding fluctuations. We quantify the work content and work of formation of arbitrary finite dimensional quantum states when the fluctuations in work are bounded by a given amount c. By varying c we interpolate between the standard and minimum free energies. We derive fundamental trade-offs between the magnitude of work and its fluctuations. As one application of these results, we derive the corrected Carnot efficiency of a qubit heat engine with bounded fluctuations.

Work extraction from quantum systems with bounded fluctuations in work

PubMed Central

Richens, Jonathan G.; Masanes, Lluis

2016-01-01

In the standard framework of thermodynamics, work is a random variable whose average is bounded by the change in free energy of the system. This average work is calculated without regard for the size of its fluctuations. Here we show that for some processes, such as reversible cooling, the fluctuations in work diverge. Realistic thermal machines may be unable to cope with arbitrarily large fluctuations. Hence, it is important to understand how thermodynamic efficiency rates are modified by bounding fluctuations. We quantify the work content and work of formation of arbitrary finite dimensional quantum states when the fluctuations in work are bounded by a given amount c. By varying c we interpolate between the standard and minimum free energies. We derive fundamental trade-offs between the magnitude of work and its fluctuations. As one application of these results, we derive the corrected Carnot efficiency of a qubit heat engine with bounded fluctuations. PMID:27886177

Work extraction from quantum systems with bounded fluctuations in work

NASA Astrophysics Data System (ADS)

Richens, Jonathan G.; Masanes, Lluis

2016-11-01

In the standard framework of thermodynamics, work is a random variable whose average is bounded by the change in free energy of the system. This average work is calculated without regard for the size of its fluctuations. Here we show that for some processes, such as reversible cooling, the fluctuations in work diverge. Realistic thermal machines may be unable to cope with arbitrarily large fluctuations. Hence, it is important to understand how thermodynamic efficiency rates are modified by bounding fluctuations. We quantify the work content and work of formation of arbitrary finite dimensional quantum states when the fluctuations in work are bounded by a given amount c. By varying c we interpolate between the standard and minimum free energies. We derive fundamental trade-offs between the magnitude of work and its fluctuations. As one application of these results, we derive the corrected Carnot efficiency of a qubit heat engine with bounded fluctuations.

An Efficient Algorithm for Mapping Imaging Data to 3D Unstructured Grids in Computational Biomechanics

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

Einstein, Daniel R.; Kuprat, Andrew P.; Jiao, Xiangmin

2013-01-01

Geometries for organ scale and multiscale simulations of organ function are now routinely derived from imaging data. However, medical images may also contain spatially heterogeneous information other than geometry that are relevant to such simulations either as initial conditions or in the form of model parameters. In this manuscript, we present an algorithm for the efficient and robust mapping of such data to imaging based unstructured polyhedral grids in parallel. We then illustrate the application of our mapping algorithm to three different mapping problems: 1) the mapping of MRI diffusion tensor data to an unstuctured ventricular grid; 2) the mappingmore » of serial cyro-section histology data to an unstructured mouse brain grid; and 3) the mapping of CT-derived volumetric strain data to an unstructured multiscale lung grid. Execution times and parallel performance are reported for each case.« less

Improving the power efficiency of SOA-based UWB over fiber systems via pulse shape randomization

NASA Astrophysics Data System (ADS)

Taki, H.; Azou, S.; Hamie, A.; Al Housseini, A.; Alaeddine, A.; Sharaiha, A.

2016-09-01

A simple pulse shape randomization scheme is considered in this paper for improving the performance of ultra wide band (UWB) communication systems using On Off Keying (OOK) or pulse position modulation (PPM) formats. The advantage of the proposed scheme, which can be either employed for impulse radio (IR) or for carrier-based systems, is first theoretically studied based on closed-form derivations of power spectral densities. Then, we investigate an application to an IR-UWB over optical fiber system, by utilizing the 4th and 5th orders of Gaussian derivatives. Our approach proves to be effective for 1 Gbps-PPM and 2 Gbps-OOK transmissions, with an advantage in terms of power efficiency for short distances. We also examine the performance for a system employing an in-line Semiconductor Optical Amplifier (SOA) with the view to achieve a reach extension, while limiting the cost and system complexity.

Steam gasification of tyre waste, poplar, and refuse-derived fuel: a comparative analysis.

PubMed

Galvagno, S; Casciaro, G; Casu, S; Martino, M; Mingazzini, C; Russo, A; Portofino, S

2009-02-01

In the field of waste management, thermal disposal is a treatment option able to recover resources from "end of life" products. Pyrolysis and gasification are emerging thermal treatments that work under less drastic conditions in comparison with classic direct combustion, providing for reduced gaseous emissions of heavy metals. Moreover, they allow better recovery efficiency since the process by-products can be used as fuels (gas, oils), for both conventional (classic engines and heaters) and high efficiency apparatus (gas turbines and fuel cells), or alternatively as chemical sources or as raw materials for other processes. This paper presents a comparative study of a steam gasification process applied to three different waste types (refuse-derived fuel, poplar wood and scrap tyres), with the aim of comparing the corresponding yields and product compositions and exploring the most valuable uses of the by-products.

Interaction of Benzimidazoles and Benzotriazole: Its Corrosion Protection Properties on Mild Steel in Hydrochloric Acid

NASA Astrophysics Data System (ADS)

Ramya, K.; Mohan, Revathi; Joseph, Abraham

2014-11-01

Synergistic hydrogen-bonded interaction of alkyl benzimidazoles and 1,2,3-benzotrizole and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies, and computational methods. The extent of synergistic interaction increases with temperature. Quantum chemical approach is used to calculate some electronic properties of the molecules and to ascertain the synergistic interaction, inhibitive effect, and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to some parameters, such as total energy, E HOMO, E LUMO, and gap energy (Δ E). 1,2,3-Benzotrizole interacts with benzimidazoles derivatives up to a bond length of approximately 1.99 Å. This interaction represents the formation of a hydrogen bond between the 1,2,3-benzotrizole and benzimidazoles. This synergistic interaction of 1,2,3-benzotrizole and benzimidazole derivatives offers extended inhibition efficiency toward mild steel in hydrochloric acid.

Efficient DNA binding and nuclear uptake by distamycin derivatives conjugated to octa-arginine sequences.

PubMed

Vázquez, Olalla; Blanco-Canosa, Juan B; Vázquez, M Eugenio; Martínez-Costas, Jose; Castedo, Luis; Mascareñas, José L

2008-11-24

Efficient targeting of DNA by designed molecules requires not only careful fine-tuning of their DNA-recognition properties, but also appropriate cell internalization of the compounds so that they can reach the cell nucleus in a short period of time. Previous observations in our group on the relatively high affinity displayed by conjugates between distamycin derivatives and bZIP basic regions for A-rich DNA sites, led us to investigate whether the covalent attachment of a positively charged cell-penetrating peptide to a distamycin-like tripyrrole might yield high affinity DNA binders with improved cell internalization properties. Our work has led to the discovery of synthetic tripyrrole-octa-arginine conjugates that are capable of targeting specific DNA sites that contain A-rich tracts with low nanomolar affinity; they simultaneously exhibit excellent membrane and nuclear translocation properties in living HeLa cells.

Derived virtual devices: a secure distributed file system mechanism

NASA Technical Reports Server (NTRS)

VanMeter, Rodney; Hotz, Steve; Finn, Gregory

1996-01-01

This paper presents the design of derived virtual devices (DVDs). DVDs are the mechanism used by the Netstation Project to provide secure shared access to network-attached peripherals distributed in an untrusted network environment. DVDs improve Input/Output efficiency by allowing user processes to perform I/O operations directly from devices without intermediate transfer through the controlling operating system kernel. The security enforced at the device through the DVD mechanism includes resource boundary checking, user authentication, and restricted operations, e.g., read-only access. To illustrate the application of DVDs, we present the interactions between a network-attached disk and a file system designed to exploit the DVD abstraction. We further discuss third-party transfer as a mechanism intended to provide for efficient data transfer in a typical NAP environment. We show how DVDs facilitate third-party transfer, and provide the security required in a more open network environment.

An efficient plant viral expression system generating orally immunogenic Norwalk virus-like particles.

PubMed

Santi, Luca; Batchelor, Lance; Huang, Zhong; Hjelm, Brooke; Kilbourne, Jacquelyn; Arntzen, Charles J; Chen, Qiang; Mason, Hugh S

2008-03-28

Virus-like particles (VLPs) derived from enteric pathogens like Norwalk virus (NV) are well suited to study oral immunization. We previously described stable transgenic plants that accumulate recombinant NV-like particles (rNVs) that were orally immunogenic in mice and humans. The transgenic approach suffers from long generation time and modest level of antigen accumulation. We now overcome these constraints with an efficient tobacco mosaic virus (TMV)-derived transient expression system using leaves of Nicotiana benthamiana. We produced properly assembled rNV at 0.8 mg/g leaf 12 days post-infection (dpi). Oral immunization of CD1 mice with 100 or 250 microg/dose of partially purified rNV elicited systemic and mucosal immune responses. We conclude that the plant viral transient expression system provides a robust research tool to generate abundant quantities of rNV as enriched, concentrated VLP preparations that are orally immunogenic.

An efficient plant viral expression system generating orally immunogenic Norwalk virus-like particles

PubMed Central

Santi, Luca; Batchelor, Lance; Huang, Zhong; Hjelm, Brooke; Kilbourne, Jacquelyn; Arntzen, Charles J.; Chen, Qiang; Mason, Hugh S.

2009-01-01

Virus like particles (VLPs) derived from enteric pathogens like Norwalk virus (NV) are well suited to study oral immunization. We previously described stable transgenic plants that accumulate recombinant NV-like particles (rNV) that were orally immunogenic in mice and humans. The transgenic approach suffers from long generation time and modest level of antigen accumulation. We now overcome these constraints with an efficient tobacco mosaic virus (TMV)-derived transient expression system using leaves of Nicotiana benthamiana. We produced properly assembled rNV at 0.8 mg/g leaf 12 days post infection. Oral immunization of CD1 mice with 100 or 250 μg/dose of partially purified rNV elicited systemic and mucosal immune responses. We conclude that the plant viral transient expression system provides a robust research tool to generate abundant quantities of rNV as enriched, concentrated VLP preparations that are orally immunogenic. PMID:18325641

Benzaldehyde, 2-hydroxybenzoyl hydrazone derivatives as inhibitors of the corrosion of aluminium in hydrochloric acid.

PubMed

Fouda, A S; Gouda, M M; El-Rahman, S I

2000-05-01

The effect of benzaldehyde, 2-hydroxybenzoyl hydrazone derivatives on the corrosion of aluminium in hydrochloric acid has been investigated using thermometric and polarization techniques. The inhibitive efficiency ranking of these compounds from both techniques was found to be: 2>3>1>4. The inhibitors acted as mixed-type inhibitors but the cathode is more polarized. The relative inhibitive efficiency of these compounds has been explained on the basis of structure of the inhibitors and their mode of interaction at the surface. Results show that these additives are adsorbed on an aluminium surface according to the Langmuir isotherm. Polarization measurements indicated that the rate of corrosion of aluminium rapidly increases with temperature over the range 30-55 degrees C both in the absence and in the presence of inhibitors. Some thermodynamic data of the adsorption process are calculated and discussed.

Measurement of sub-parts-per-billion levels of carbonyl compounds in marine air by a simple cartridge trapping procedure followed by liquid chromatography

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

Xianliang, Zhou; Mopper, K.

1990-10-01

Carbonyl compounds in clean marine air were trapped onto 2,4-dinitrophenylhydrazine- (DNPH-) coated cartridges, and their hydrazone derivatives were separated by HPLC and detected by UV absorbance. More than 20 carbonyl compounds were isolated from marine air with >92% collection efficiency. The technique employs a highly effective reagent purification procedure, which results in much lower blanks compared to previously reported trapping techniques for carbonyl compounds. Blanks were routinely <0.07 ppb for formaldehyde and acetone and <0.02 ppb for the others. Humidity and reactive gases have no detectable effect on collection efficiencies. Carbonyl-DNPH derivatives eluted from the cartridges are stable in acetonitrilemore » for at least 2 weeks, which facilitates field studies. Several previously undetected unknown carbonyl compounds were found in marine air by this technique. Typical results for open ocean and coastal marine air are shown.« less

Evaluation of Far-Field Boundary Conditions for the Gust Response Problem

NASA Technical Reports Server (NTRS)

Scott, James R.; Kreider, Kevin L.; Heminger, John A.

2002-01-01

This paper presents a detailed situ dy of four far-field boundary conditions used in solving the single airfoil gust response problem. The boundary conditions, examined are the partial Sommerfeld radiation condition with only radial derivatives, the full Sommerfeld radiation condition with both radial and tangential derivatives, the Bayliss-Turkel condition of order one, and the Hagstrom-Hariharan condition of order one. The main objectives of the study were to determine which far-field boundary condition was most accurate, which condition was least sensitive to changes in grid. and which condition was best overall in terms of both accuracy and efficiency. Through a systematic study of the flat plate gust response problem, it was determined that the Hagstrom-Hariharan condition was most accurate, the Bayliss-Turkel condition was least sensitive to changes in grid, and Bayliss-Turkel was best in terms of both accuracy and efficiency.