Continuous control of asymmetric forebody vortices in a bi-stable state

Science.gov (United States)

Wang, Qi-te; Cheng, Ke-ming; Gu, Yun-song; Li, Zhuo-qi

2018-02-01

Aiming at the problem of continuous control of asymmetric forebody vortices at a high angle of attack in a bi-stable regime, a dual synthetic jet actuator embedded in an ogive forebody was designed. Alternating unsteady disturbance with varying degree asymmetrical flow fields near the nozzles is generated by adjusting the duty cycle of the drive signal of the actuator, specifically embodying the asymmetric time-averaged pattern of jet velocity, vorticity, and turbulent kinetic energy. Experimental results show that within the range of relatively high angles of attack, including the angle-of-attack region in a bi-stable state, the lateral force of the ogive forebody is continuously controlled by adjusting the duty cycle of the drive signal; the position of the forebody vortices in space, the vorticity magnitude, the total pressure coefficient near the vortex core, and the vortex breakdown location are continuously changed with the duty cycle increased observed from the time-averaged flow field. Instantaneous flow field results indicate that although the forebody vortices are in an unsteady oscillation state, a continuous change in the forebody vortices' oscillation balance position as the duty cycle increases leads to a continuous change in the model's surface pressure distribution and time-averaged lateral force. Different from the traditional control principle, in this study, other different degree asymmetrical states of the forebody vortices except the bi-stable state are obtained using the dual synthetic jet control technology.

Palladium-catalyzed asymmetric alkylation in the synthesis of cyclopentanoid and cycloheptanoid core structures bearing all-carbon quaternary stereocenters

KAUST Repository

Hong, Allen Y.

2011-12-01

General catalytic asymmetric routes toward cyclopentanoid and cycloheptanoid core structures embedded in numerous natural products have been developed. The central stereoselective transformation in our divergent strategies is the enantioselective decarboxylative alkylation of seven-membered β-ketoesters to form α-quaternary vinylogous esters. Recognition of the unusual reactivity of β-hydroxyketones resulting from the addition of hydride or organometallic reagents enabled divergent access to γ-quaternary acylcyclopentenes through a ring contraction pathway or γ-quaternary cycloheptenones through a carbonyl transposition pathway. Synthetic applications of these compounds were explored through the preparation of mono-, bi-, and tricyclic derivatives that can serve as valuable intermediates for the total synthesis of complex natural products. This work complements our previous work with cyclohexanoid systems.

Asymmetric Horner-Wadsworth-Emmons Reactions with meso-Dialdehydes: Scope, Mechanism, and Synthetic Applications

DEFF Research Database (Denmark)

Rein, Tobias; Vares, Lauri; Kawasaki, Ikuo

1999-01-01

Asymmetric Homer-Wadsworth-Emmons reactions between chiral phosphonate reagents and various meso-dialdehydes have been investigated. A mechanistic model useful for rationalizing the experimentally observed stereoselectivities is presented. Furthermore; strategies for applying these reactions...

Asymmetric Total Synthesis of Ieodomycin B

Directory of Open Access Journals (Sweden)

Shuangjie Lin

2017-01-01

Full Text Available Ieodomycin B, which shows in vitro antimicrobial activity, was isolated from a marine Bacillus species. A novel asymmetric total synthetic approach to ieodomycin B using commercially available geraniol was achieved. The approach involves the generation of 1,3-trans-dihydroxyl at C-3 and C-5 positions via a Crimmins-modified Evans aldol reaction and a chelation-controlled Mukaiyama aldol reaction of a p-methoxybenzyl-protected aldehyde, as well as the generation of a lactone ring in a deprotection–lactonization one-pot reaction.

Effects of Asymmetric Secondary Eyewall on Tropical Cyclone Evolution in Hurricane Ike (2008)

Science.gov (United States)

Zhang, Guosheng; Perrie, William

2018-02-01

The secondary eyewall plays an important role in tropical cyclone evolution and intensification and is routinely assumed to be axisymmetric. A unique opportunity to investigate the characteristics of the secondary eyewall in two dimensions is provided by the high spatial resolution (about 1 km) sea surface winds that were observed by spaceborne synthetic aperture radar over Hurricane Ike (2008). Here we extract the asymmetric characteristics using our Symmetric Hurricane Estimates for Winds model and analyze the related hurricane evolution by comparisons with aircraft measurements. Compared to the classic eyewall replacement cycle theory, our investigation finds that the primary eyewall did not weaken and the secondary eyewall did not shrink over a period of more than 30 hr. We suggest that the reason for this persistence is that a boundary layer inflow pathway is provided by the relatively low winds in the asymmetric secondary eyewall area, as observed by synthetic aperture radar.

pClone: Synthetic Biology Tool Makes Promoter Research Accessible to Beginning Biology Students

Science.gov (United States)

Eckdahl, Todd; Cronk, Brian; Andresen, Corinne; Frederick, Paul; Huckuntod, Samantha; Shinneman, Claire; Wacker, Annie; Yuan, Jason

2014-01-01

The Vision and Change report recommended genuine research experiences for undergraduate biology students. Authentic research improves science education, increases the number of scientifically literate citizens, and encourages students to pursue research. Synthetic biology is well suited for undergraduate research and is a growing area of science. We developed a laboratory module called pClone that empowers students to use advances in molecular cloning methods to discover new promoters for use by synthetic biologists. Our educational goals are consistent with Vision and Change and emphasize core concepts and competencies. pClone is a family of three plasmids that students use to clone a new transcriptional promoter or mutate a canonical promoter and measure promoter activity in Escherichia coli. We also developed the Registry of Functional Promoters, an open-access database of student promoter research results. Using pre- and posttests, we measured significant learning gains among students using pClone in introductory biology and genetics classes. Student posttest scores were significantly better than scores of students who did not use pClone. pClone is an easy and affordable mechanism for large-enrollment labs to meet the high standards of Vision and Change. PMID:26086659

Asymmetric synthesis of synthetic alkaloids by a tandem biocatalysis/Ugi/Pictet-Spengler-type

NARCIS (Netherlands)

Znabet, A.; Zonneveld, J.; Janssen, E.; de Kanter, F.J.J.; Helliwell, M.; Turner, N.J.; Ruijter, E.; Orru, R.V.A.

2010-01-01

We have combined the biocatalytic desymmetrization of 3,4-cis-substituted meso-pyrrolidines with an Ugi-type multicomponent reaction followed in situ by a Pictet-Spengler-type cyclization reaction sequence for the rapid asymmetric synthesis of alkaloid-like polycyclic compounds. © The Royal Society

Efficient One-Step Fusion PCR Based on Dual-Asymmetric Primers and Two-Step Annealing

DEFF Research Database (Denmark)

Liu, Yilan; Chen, Jinjin; Thygesen, Anders

2018-01-01

Gene splicing by fusion PCR is a versatile and widely used methodology, especially in synthetic biology. We here describe a rapid method for splicing two fragments by one-round fusion PCR with a dual-asymmetric primers and two-step annealing (ODT) method. During the process, the asymmetric...... intermediate fragments were generated in the early stage. Thereafter, they were hybridized in the subsequent cycles to serve as template for the target full-length product. The process parameters such as primer ratio, elongation temperature and cycle numbers were optimized. In addition, the fusion products...

Enantioselective syntheses and biological studies of aeruginosin 298-A and its analogs: application of catalytic asymmetric phase-transfer reaction.

Science.gov (United States)

Fukuta, Yuhei; Ohshima, Takashi; Gnanadesikan, Vijay; Shibuguchi, Tomoyuki; Nemoto, Tetsuhiro; Kisugi, Takaya; Okino, Tatsufumi; Shibasaki, Masakatsu

2004-04-13

Aeruginosin 298-A was isolated from the freshwater cyanobacterium Microcystis aeruginosa (NIES-298) and is an equipotent thrombin and trypsin inhibitor. A variety of analogs were synthesized to gain insight into the structure-activity relations. We developed a versatile synthetic process for aeruginosin 298-A as well as several attractive analogs, in which all stereocenters were controlled by catalytic asymmetric phase-transfer reaction promoted by two-center asymmetric catalysts and catalytic asymmetric epoxidation promoted by a lanthanide-BINOL complex. Furthermore, serine protease inhibitory activities of aeruginosin 298-A and its analogs were examined.

Broadband Wireline Provider Service: Asymmetric xDSL; BBRI_DSLasym12

Data.gov (United States)

University of Rhode Island Geospatial Extension Program — This dataset represents the availability of wireline broadband Internet access in Rhode Island via Asymmetric xDSL technology. Broadband availability is summarized...

Multiply-Imputed Synthetic Data: Advice to the Imputer

Directory of Open Access Journals (Sweden)

Loong Bronwyn

2017-12-01

Full Text Available Several statistical agencies have started to use multiply-imputed synthetic microdata to create public-use data in major surveys. The purpose of doing this is to protect the confidentiality of respondents’ identities and sensitive attributes, while allowing standard complete-data analyses of microdata. A key challenge, faced by advocates of synthetic data, is demonstrating that valid statistical inferences can be obtained from such synthetic data for non-confidential questions. Large discrepancies between observed-data and synthetic-data analytic results for such questions may arise because of uncongeniality; that is, differences in the types of inputs available to the imputer, who has access to the actual data, and to the analyst, who has access only to the synthetic data. Here, we discuss a simple, but possibly canonical, example of uncongeniality when using multiple imputation to create synthetic data, which specifically addresses the choices made by the imputer. An initial, unanticipated but not surprising, conclusion is that non-confidential design information used to impute synthetic data should be released with the confidential synthetic data to allow users of synthetic data to avoid possible grossly conservative inferences.

Broadband chirality and asymmetric transmission in ultrathin 90°-twisted Babinet-inverted metasurfaces

Science.gov (United States)

Shi, J. H.; Ma, H. F.; Guan, C. Y.; Wang, Z. P.; Cui, T. J.

2014-04-01

A broadband asymmetric transmission of linearly polarized waves with totally suppressed copolarization transmission is experimentally demonstrated in ultrathin 90°-twisted Babinet-inverted metasurfaces constructed by an array of asymmetrically split ring apertures. The only accessible direction-dependent cross-polarization transmission is allowed in this anisotropic chiral metamaterial. Through full-wave simulation and experiment results, the bilayered Babinet-inverted metasurface reveals broadband artificial chirality and asymmetric transmission, with a transmission contrast that is better than 17.7 dB within a 50% relative bandwidth for two opposite directions. In particular, we can modify polarization conversion efficiency and the bandwidth of asymmetric transmission via parametric study.

Accelerating foreign-key joins using asymmetric memory channels

NARCIS (Netherlands)

Pirk, H.; Manegold, S.; Kersten, M.

2011-01-01

Indexed Foreign-Key Joins expose a very asymmetric access pattern: the Foreign-Key Index is sequentially scanned whilst the Primary-Key table is target of many quasi-random lookups which is the dominant cost factor. To reduce the costs of the random lookups the fact-table can be (re-) partitioned at

Unravelling Thiol’s Role in Directing Asymmetric Growth of Au Nanorod–Au Nanoparticle Dimers

KAUST Repository

Huang, Jianfeng

2015-12-15

Asymmetric nanocrystals have practical significance in nanotechnologies but present fundamental synthetic challenges. Thiol ligands have proven effective in breaking the symmetric growth of metallic nanocrystals but their exact roles in the synthesis remain elusive. Here, we synthesized an unprecedented Au nanorod-Au nanoparticle (AuNR-AuNP) dimer structure with the assistance of a thiol ligand. On the basis of our experimental observations, we unraveled for the first time that the thiol could cause an inhomogeneous distribution of surface strains on the seed crystals as well as a modulated reduction rate of metal precursors, which jointly induced the asymmetric growth of monometallic dimers. © 2015 American Chemical Society.

Hadron scattering in an asymmetric box

International Nuclear Information System (INIS)

Li Xin; Chen Ying; Meng Guozhan; Feng Xu; Gong Ming; He Song; Li Gang; Liu Chuan; Liu Yubin; Ma Jianping; Meng Xiangfei; Shen Yan; Zhang Jianbo

2007-01-01

We propose to study hadron-hadron scattering using lattice QCD in an asymmetric box which allows one to access more non-degenerate low-momentum modes for a given volume. The conventional Luescher's formula applicable in a symmetric box is modified accordingly. To illustrate the feasibility of this approach, pion-pion elastic scattering phase shifts in the I = 2, J = 0 channel are calculated within quenched approximation using improved gauge and Wilson fermion actions on anisotropic lattices in an asymmetric box. After the chiral and continuum extrapolation, we find that our quenched results for the scattering phase shifts in this channel are consistent with the experimental data when the three-momentum of the pion is below 300MeV. Agreement is also found when compared with previous theoretical results from lattice and other means. Moreover, with the usage of asymmetric volume, we are able to compute the scattering phases in the low-momentum range (pion three momentum less than about 350MeV in the center of mass frame) for over a dozen values of the pion three-momenta, much more than using the conventional symmetric box with comparable volume

Accessible solitons of fractional dimension

Energy Technology Data Exchange (ETDEWEB)

Zhong, Wei-Ping, E-mail: zhongwp6@126.com [Department of Electronic and Information Engineering, Shunde Polytechnic, Guangdong Province, Shunde 528300 (China); Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Belić, Milivoj [Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Zhang, Yiqi [Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China)

2016-05-15

We demonstrate that accessible solitons described by an extended Schrödinger equation with the Laplacian of fractional dimension can exist in strongly nonlocal nonlinear media. The soliton solutions of the model are constructed by two special functions, the associated Legendre polynomials and the Laguerre polynomials in the fraction-dimensional space. Our results show that these fractional accessible solitons form a soliton family which includes crescent solitons, and asymmetric single-layer and multi-layer necklace solitons. -- Highlights: •Analytic solutions of a fractional Schrödinger equation are obtained. •The solutions are produced by means of self-similar method applied to the fractional Schrödinger equation with parabolic potential. •The fractional accessible solitons form crescent, asymmetric single-layer and multilayer necklace profiles. •The model applies to the propagation of optical pulses in strongly nonlocal nonlinear media.

Synthetic biology and biosecurity: challenging the "myths".

Science.gov (United States)

Jefferson, Catherine; Lentzos, Filippa; Marris, Claire

2014-01-01

Synthetic biology, a field that aims to "make biology easier to engineer," is routinely described as leading to an increase in the "dual-use" threat, i.e., the potential for the same scientific research to be "used" for peaceful purposes or "misused" for warfare or terrorism. Fears have been expressed that the "de-skilling" of biology, combined with online access to the genomic DNA sequences of pathogenic organisms and the reduction in price for DNA synthesis, will make biology increasingly accessible to people operating outside well-equipped professional research laboratories, including people with malevolent intentions. The emergence of do-it-yourself (DIY) biology communities and of the student iGEM competition has come to epitomize this supposed trend toward greater ease of access and the associated potential threat from rogue actors. In this article, we identify five "myths" that permeate discussions about synthetic biology and biosecurity, and argue that they embody misleading assumptions about both synthetic biology and bioterrorism. We demonstrate how these myths are challenged by more realistic understandings of the scientific research currently being conducted in both professional and DIY laboratories, and by an analysis of historical cases of bioterrorism. We show that the importance of tacit knowledge is commonly overlooked in the dominant narrative: the focus is on access to biological materials and digital information, rather than on human practices and institutional dimensions. As a result, public discourse on synthetic biology and biosecurity tends to portray speculative scenarios about the future as realities in the present or the near future, when this is not warranted. We suggest that these "myths" play an important role in defining synthetic biology as a "promissory" field of research and as an "emerging technology" in need of governance.

Studies Toward the Asymmetric Synthesis of the Right Part of the Mycalamides

OpenAIRE

Zhong, H. Marlon; Sohn, Jeong-Hun; Rawal, Viresh H.

2007-01-01

Described herein is the asymmetric synthesis of a functionalized, trioxadecalin unit that comprises the right-hand part of the mycalamides and related natural products. The synthetic route involves a 16-step sequence that accomplishes the formation of two heterocyclic rings and the generation of five stereocenters. The synthesis commenced with a C2 symmetric starting material, diethyl D-tartrate, and took advantage of a relay of diastereoselective reactions to extend this four-carbon chain an...

Application of Carbohydrate-Templated Asymmetric Diels-Alder Reaction to the Syntheses of ent-Penicillones A and B.

Science.gov (United States)

Weng, Chia-Hao; Hsu, Day-Shin; Liao, Chun-Chen

2016-11-18

Total syntheses of ent-penicillones A (ent-1) and B (ent-2) from 3,5-dimethylcatechol (3) were accomplished in 10 and 9 synthetic steps, respectively. A carbohydrate-templated asymmetric intramolecular Diels-Alder reaction of a masked o-benzoquinone (MOB) 9 and an aqueous acid-catalyzed intramolecular aldol reaction are the key synthetic steps. In addition, the absolute configurations of the bicyclo[2.2.2]oct-5-en-2-one core obtained from the per-O-benzylated α-d-glucopyranosyl as a carbohydrate template in the intramolecular Diels-Alder reaction of MOBs were revised.

Synthetic Biology: Knowledge Accessed by Everyone (Open Sources)

Science.gov (United States)

Sánchez Reyes, Patricia Margarita

2016-01-01

Using the principles of biology, along with engineering and with the help of computer, scientists manage to copy. DNA sequences from nature and use them to create new organisms. DNA is created through engineering and computer science managing to create life inside a laboratory. We cannot dismiss the role that synthetic biology could lead in…

Ships as salient objects in synthetic aperture radar imaginary

CSIR Research Space (South Africa)

Schwegmann, Colin P

2016-07-01

Full Text Available The widespread access to Synthetic Aperture Radar data has created a need for more precise ship extraction, specifically in low-to-medium resolution imagery. While Synthetic Aperture Radar pixel resolution is improving for a large swaths...

Synthetic biology and biosecurity: challenging the ‘myths’

Directory of Open Access Journals (Sweden)

Catherine eJefferson

2014-08-01

Full Text Available Synthetic biology, a field that aims to ‘make biology easier to engineer’, is routinely described as leading to an increase in the ‘dual use’ threat, i.e. the potential for the same piece of scientific research to be ‘used’ for peaceful purposes or ‘misused’ for warfare or terrorism. Fears have been expressed that the ‘de-skilling’ of biology, combined with online access to the genomic DNA sequences of pathogenic organisms and the reduction in price for DNA synthesis, will make biology increasingly accessible to people operating outside well-equipped professional research laboratories, including people with malevolent intentions. The emergence of DIY biology communities and of the student iGEM competition has come to epitomize this supposed trend towards greater ease of access and the associated potential threat from rogue actors. In this article, we identify 5 ‘myths’ that permeate discussions about synthetic biology and biosecurity, and argue that they embody misleading assumptions about both synthetic biology and bioterrorism. We demonstrate how these myths are challenged by more realistic understandings of the scientific research currently being conducted in both professional and DIY laboratories, and by an analysis of historical cases of bioterrorism. We show that the importance of tacit knowledge is commonly overlooked in the dominant narrative: the focus is on access to biological materials and digital information, rather than on human practices and institutional dimensions. As a result, public discourse on synthetic biology and biosecurity tends to portray speculative scenarios about the future as realities in the present or the near future, when this is not warranted. We suggest that these ‘myths’ play an important role in defining synthetic biology as a ‘promissory’ field of research and as an ‘emerging technology’ in need of governance.

Synthetic Biology and Biosecurity: Challenging the “Myths”

Science.gov (United States)

Jefferson, Catherine; Lentzos, Filippa; Marris, Claire

2014-01-01

Synthetic biology, a field that aims to “make biology easier to engineer,” is routinely described as leading to an increase in the “dual-use” threat, i.e., the potential for the same scientific research to be “used” for peaceful purposes or “misused” for warfare or terrorism. Fears have been expressed that the “de-skilling” of biology, combined with online access to the genomic DNA sequences of pathogenic organisms and the reduction in price for DNA synthesis, will make biology increasingly accessible to people operating outside well-equipped professional research laboratories, including people with malevolent intentions. The emergence of do-it-yourself (DIY) biology communities and of the student iGEM competition has come to epitomize this supposed trend toward greater ease of access and the associated potential threat from rogue actors. In this article, we identify five “myths” that permeate discussions about synthetic biology and biosecurity, and argue that they embody misleading assumptions about both synthetic biology and bioterrorism. We demonstrate how these myths are challenged by more realistic understandings of the scientific research currently being conducted in both professional and DIY laboratories, and by an analysis of historical cases of bioterrorism. We show that the importance of tacit knowledge is commonly overlooked in the dominant narrative: the focus is on access to biological materials and digital information, rather than on human practices and institutional dimensions. As a result, public discourse on synthetic biology and biosecurity tends to portray speculative scenarios about the future as realities in the present or the near future, when this is not warranted. We suggest that these “myths” play an important role in defining synthetic biology as a “promissory” field of research and as an “emerging technology” in need of governance. PMID:25191649

Asymmetric Construction of Benzindoloquinolizidine: Application of An Organocatalytic Enantioselective Conjugate Addition-Cyclization Cascade Reaction

International Nuclear Information System (INIS)

Kim, Cheolwoong; Seo, Seung Woo; Lee, Yona; Kim, Sunggon

2014-01-01

We have developed the synthetic methodology of enantioenriched benzindoloquinolizidines based on the organocatalytic enantioselective conjugate addition-cyclization cascade reaction of o-N-(3-indoleacetyl)amino-cinnamaldehydes with malonates followed by an acid-catalyzed intramolecular Pictet-Spengler type cyclization. The asymmetric reaction using diphenylprolinol TMS ether as an organocatalyst produces the desired products with good to excellent yields and high enantioselectivities (up to 98% ee). The evaluation of the applications of this synthetic methodology for generating enantioenriched benzindolo-quinolizidines and studies on the biological activity of these compounds against human prostate cancer in particular are now in progress. Results of these studies will be presented in due course. Many new types of chemical reactions have been developed to facilitate easier synthesis of complex compounds. Among the strategies, domino reactions, which have been utilized for the efficient and stereoselective construction of complex molecules from simple precursors in a single process, are widely used due to their high synthetic efficiency by reducing both the number of synthetic operation required and the quantities of chemicals and solvents used

Living GenoChemetics by hyphenating synthetic biology and synthetic chemistry in vivo.

Science.gov (United States)

Sharma, Sunil V; Tong, Xiaoxue; Pubill-Ulldemolins, Cristina; Cartmell, Christopher; Bogosyan, Emma J A; Rackham, Emma J; Marelli, Enrico; Hamed, Refaat B; Goss, Rebecca J M

2017-08-09

Marrying synthetic biology with synthetic chemistry provides a powerful approach toward natural product diversification, combining the best of both worlds: expediency and synthetic capability of biogenic pathways and chemical diversity enabled by organic synthesis. Biosynthetic pathway engineering can be employed to insert a chemically orthogonal tag into a complex natural scaffold affording the possibility of site-selective modification without employing protecting group strategies. Here we show that, by installing a sufficiently reactive handle (e.g., a C-Br bond) and developing compatible mild aqueous chemistries, synchronous biosynthesis of the tagged metabolite and its subsequent chemical modification in living culture can be achieved. This approach can potentially enable many new applications: for example, assay of directed evolution of enzymes catalyzing halo-metabolite biosynthesis in living cells or generating and following the fate of tagged metabolites and biomolecules in living systems. We report synthetic biological access to new-to-nature bromo-metabolites and the concomitant biorthogonal cross-coupling of halo-metabolites in living cultures.Coupling synthetic biology and chemical reactions in cells is a challenging task. The authors engineer bacteria capable of generating bromo-metabolites, develop a mild Suzuki-Miyaura cross-coupling reaction compatible with cell growth and carry out the cross-coupling chemistry in live cell cultures.

Asymmetric epigenetic modification and elimination of rDNA sequences by polyploidization in wheat.

Science.gov (United States)

Guo, Xiang; Han, Fangpu

2014-11-01

rRNA genes consist of long tandem repeats clustered on chromosomes, and their products are important functional components of the ribosome. In common wheat (Triticum aestivum), rDNA loci from the A and D genomes were largely lost during the evolutionary process. This biased DNA elimination may be related to asymmetric transcription and epigenetic modifications caused by the polyploid formation. Here, we observed both sets of parental nucleolus organizing regions (NORs) were expressed after hybridization, but asymmetric silencing of one parental NOR was immediately induced by chromosome doubling, and reversing the ploidy status could not reactivate silenced NORs. Furthermore, increased CHG and CHH DNA methylation on promoters was accompanied by asymmetric silencing of NORs. Enrichment of H3K27me3 and H3K9me2 modifications was also observed to be a direct response to increased DNA methylation and transcriptional inactivation of NOR loci. Both A and D genome NOR loci with these modifications started to disappear in the S4 generation and were completely eliminated by the S7 generation in synthetic tetraploid wheat. Our results indicated that asymmetric epigenetic modification and elimination of rDNA sequences between different donor genomes may lead to stable allopolyploid wheat with increased differentiation and diversity. © 2014 American Society of Plant Biologists. All rights reserved.

Copper(I)-Catalyzed Asymmetric Desymmetrization through Inverse-Electron-Demand aza-Diels-Alder Reaction: Efficient Access to Tetrahydropyridazines Bearing a Unique α-Chiral Silane Moiety.

Science.gov (United States)

Wei, Liang; Zhou, Yu; Song, Zhi-Min; Tao, Hai-Yan; Lin, Zhenyang; Wang, Chun-Jiang

2017-04-11

An unprecedented copper(I)-catalyzed asymmetric desymmetrization of 5-silylcyclopentadienes with in situ formed azoalkene was realized through an inverse-electron-demand aza-Diels-Alder reaction (IEDDA) pathway, in which 5-silylcyclopentadienes served as efficient enophiles. This new protocol provides a facile access to the biologically important heterocyclic tetrahydropyridazines containing a unique α-chiral silane motif and three adjoining stereogenic centers in generally good yield (up to 92 %) with exclusive regioselectivity, high diastereoselectivity (>20:1 diastereomeric ratio), and excellent enantioselectivity (up to 98 % enantiomeric excess). DFT calculations and control experiments further confirmed the proposed reaction mechanism. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Asymmetric catalysis in Brazil: development and potential for advancement of Brazilian chemical industry

International Nuclear Information System (INIS)

Braga, Antonio Luiz; Luedtke, Diogo Seibert; Schneider, Paulo Henrique; Andrade, Leandro Helgueira; Paixao, Marcio Weber

2013-01-01

The preparation of enantiomerically pure or enriched substances is of fundamental importance to pharmaceutical, food, agrochemical, and cosmetics industries and involves a growing market of hundreds of billions of dollars. However, most chemical processes used for their production are not environmentally friendly because in most cases, stoichiometric amounts of chiral inductors are used and substantial waste is produced. In this context, asymmetric catalysis has emerged as an efficient tool for the synthesis of enantiomerically enriched compounds using chiral catalysts. More specifically, considering the current scenario in the Brazilian chemical industry, especially that of pharmaceuticals, the immediate prospect for the use of synthetic routes developed in Brazil in an enantioselective fashion or even the discovery of new drugs is practically null. Currently, the industrial production of drugs in Brazil is primarily focused on the production of generic drugs and is basically supported by imports of intermediates from China and India. In order to change this panorama and move forward toward the gradual incorporation of genuinely Brazilian synthetic routes, strong incentive policies, especially those related to continuous funding, will be needed. These incentives could be a breakthrough once we establish several research groups working in the area of organic synthesis and on the development and application of chiral organocatalysts and ligands in asymmetric catalysis, thus contributing to boost the development of the Brazilian chemical industry. Considering these circumstances, Brazil can benefit from this opportunity because we have a wide biodiversity and a large pool of natural resources that can be used as starting materials for the production of new chiral catalysts and are creating competence in asymmetric catalysis and related areas. This may decisively contribute to the growth of chemistry in our country. (author)

Organocatalytic Asymmetric Michael Addition of 4-Hydroxycoumarin to β,γ-Unsaturated α-Keto Esters

Energy Technology Data Exchange (ETDEWEB)

Suh, Chang Won; Han, Tae Hyun; Kim, Dae Young [Soonchunhyang Univ., Asan (Korea, Republic of)

2013-06-15

In conclusion, we have developed organocatalytic enantioselective conjugate addition reaction of 4-hydroxycoumarin (1) to β,γ-unsaturated α-keto esters 2 to afford biologically valuable warfarin derivatives 3. The process is efficiently catalyzed by a binaphthyl-modified thiourea organocatalyst. The coumarin core is present as a characteristic structural motif in a large number of natural products and biologically active molecules.1 Particularly, many of these naturally occurring 4-hydroxycoumarin and their synthetic analogues are important precursors for the synthesis of natural products and pharmaceuticals. Enantioselective organocatalytic conjugate addition of 4-hydroxycoumarin to α,β-unsaturated ketones is a straightforward method to access warfarin which is an effective anticoagulants. Although a number of reactions of α,β-unsaturated ketones as Michael acceptors have been reported, the corresponding β,γ-unsaturated α-keto esters have received relatively little attention as Michael acceptors. Recently, several groups have reported the asymmetric Michael addition of 4-hydroxycoumarin to β,γ-unsaturated α-keto esters catalyzed by Cu(II)-bisoxazoline, N,N'-dioxide-Ni(II) complexes, thiourea catalysts. Although several efficient methods have been achieved by these systems, an effective method for the synthesis of warfarin analogues is still a challenge.

Organocatalytic Asymmetric Michael Addition of 4-Hydroxycoumarin to β,γ-Unsaturated α-Keto Esters

International Nuclear Information System (INIS)

Suh, Chang Won; Han, Tae Hyun; Kim, Dae Young

2013-01-01

In conclusion, we have developed organocatalytic enantioselective conjugate addition reaction of 4-hydroxycoumarin (1) to β,γ-unsaturated α-keto esters 2 to afford biologically valuable warfarin derivatives 3. The process is efficiently catalyzed by a binaphthyl-modified thiourea organocatalyst. The coumarin core is present as a characteristic structural motif in a large number of natural products and biologically active molecules.1 Particularly, many of these naturally occurring 4-hydroxycoumarin and their synthetic analogues are important precursors for the synthesis of natural products and pharmaceuticals. Enantioselective organocatalytic conjugate addition of 4-hydroxycoumarin to α,β-unsaturated ketones is a straightforward method to access warfarin which is an effective anticoagulants. Although a number of reactions of α,β-unsaturated ketones as Michael acceptors have been reported, the corresponding β,γ-unsaturated α-keto esters have received relatively little attention as Michael acceptors. Recently, several groups have reported the asymmetric Michael addition of 4-hydroxycoumarin to β,γ-unsaturated α-keto esters catalyzed by Cu(II)-bisoxazoline, N,N'-dioxide-Ni(II) complexes, thiourea catalysts. Although several efficient methods have been achieved by these systems, an effective method for the synthesis of warfarin analogues is still a challenge

Properties of Asymmetric Detrended Fluctuation Analysis in the time series of RR intervals

Science.gov (United States)

Piskorski, J.; Kosmider, M.; Mieszkowski, D.; Krauze, T.; Wykretowicz, A.; Guzik, P.

2018-02-01

Heart rate asymmetry is a phenomenon by which the accelerations and decelerations of heart rate behave differently, and this difference is consistent and unidirectional, i.e. in most of the analyzed recordings the inequalities have the same directions. So far, it has been established for variance and runs based types of descriptors of RR intervals time series. In this paper we apply the newly developed method of Asymmetric Detrended Fluctuation Analysis, which so far has mainly been used with economic time series, to the set of 420 stationary 30 min time series of RR intervals from young, healthy individuals aged between 20 and 40. This asymmetric approach introduces separate scaling exponents for rising and falling trends. We systematically study the presence of asymmetry in both global and local versions of this method. In this study global means "applying to the whole time series" and local means "applying to windows jumping along the recording". It is found that the correlation structure of the fluctuations left over after detrending in physiological time series shows strong asymmetric features in both magnitude, with α+ physiological data after shuffling or with a group of symmetric synthetic time series.

Fault detection and diagnosis in asymmetric multilevel inverter using artificial neural network

Science.gov (United States)

Raj, Nithin; Jagadanand, G.; George, Saly

2018-04-01

The increased component requirement to realise multilevel inverter (MLI) fallout in a higher fault prospect due to power semiconductors. In this scenario, efficient fault detection and diagnosis (FDD) strategies to detect and locate the power semiconductor faults have to be incorporated in addition to the conventional protection systems. Even though a number of FDD methods have been introduced in the symmetrical cascaded H-bridge (CHB) MLIs, very few methods address the FDD in asymmetric CHB-MLIs. In this paper, the gate-open circuit FDD strategy in asymmetric CHB-MLI is presented. Here, a single artificial neural network (ANN) is used to detect and diagnose the fault in both binary and trinary configurations of the asymmetric CHB-MLIs. In this method, features of the output voltage of the MLIs are used as to train the ANN for FDD method. The results prove the validity of the proposed method in detecting and locating the fault in both asymmetric MLI configurations. Finally, the ANN response to the input parameter variation is also analysed to access the performance of the proposed ANN-based FDD strategy.

Palladium-catalyzed Asymmetric Hydrosilylation of Styrene and Its Derivatives with Chiral Phosphoramidite Ligands Containing Chiral Ferrocenyl Amine

Energy Technology Data Exchange (ETDEWEB)

Park, Hyun-Sub; Kim, Min Young; Ahn, Hyo Jin; Han, Jin Wook [Hanyang University, Seoul (Korea, Republic of)

2016-06-15

Asymmetric hydrosilylation was one of the most effective methods, which provided optically active organosilanes as a synthetically useful intermediate in organic synthesis. One useful transformation is the Tamao-Fleming oxidation, which is an oxidation reaction of carbon[BOND]silicone bond to afford optically active alcohols with retention of configuration. It is demonstrated that a palladium catalyst coordinating with phosphoramidite ligand (S {sub a},R {sub c},R {sub c,})-L3a from (S)-BINOL and chiral bis((R)-1-ferrocenylethyl) amine shows a high catalytic activity and enantioselectivity up to 97% ee in asymmetric hydrosilylation of styrene and its derivatives. The hydrosilylation of various olefin substrates using these ligands is in progress.

Organocatalytic asymmetric allylic amination of Morita–Baylis–Hillman carbonates of isatins

Directory of Open Access Journals (Sweden)

Hang Zhang

2012-08-01

Full Text Available The investigation of a Lewis base catalyzed asymmetric allylic amination of Morita–Baylis–Hillman carbonates derived from isatins afforded an electrophilic pathway to access multifunctional oxindoles bearing a C3-quaternary stereocenter, provided with good to excellent enantioselectivity (up to 94% ee and in high yields (up to 97%.

Synthetic biology analysed tools for discussion and evaluation

CERN Document Server

2016-01-01

Synthetic biology is a dynamic, young, ambitious, attractive, and heterogeneous scientific discipline. It is constantly developing and changing, which makes societal evaluation of this emerging new science a challenging task, prone to misunderstandings. Synthetic biology is difficult to capture, and confusion arises not only regarding which part of synthetic biology the discussion is about, but also with respect to the underlying concepts in use. This book offers a useful toolbox to approach this complex and fragmented field. It provides a biological access to the discussion using a 'layer' model that describes the connectivity of synthetic or semisynthetic organisms and cells to the realm of natural organisms derived by evolution. Instead of directly reviewing the field as a whole, firstly our book addresses the characteristic features of synthetic biology that are relevant to the societal discussion. Some of these features apply only to parts of synthetic biology, whereas others are relevant to synthetic bi...

Enantioselective syntheses of aeruginosin 298-A and its analogues using a catalytic asymmetric phase-transfer reaction and epoxidation.

Science.gov (United States)

Ohshima, Takashi; Gnanadesikan, Vijay; Shibuguchi, Tomoyuki; Fukuta, Yuhei; Nemoto, Tetsuhiro; Shibasaki, Masakatsu

2003-09-17

We developed a versatile synthetic process for aeruginosin 298-A as well as several attractive analogues, in which all stereocenters were controlled by a catalytic asymmetric phase-transfer reaction and epoxidation. Furthermore, drastic counteranion effects in phase-transfer catalysis were observed for the first time, making it possible to three-dimensionally fine-tune the catalyst (ketal part, aromatic part, and counteranion).

Enantioselective Direct α-Amination of Aldehydes via a Photoredox Mechanism: A Strategy for Asymmetric Amine Fragment Coupling

OpenAIRE

Cecere, Giuseppe; Koenig, Christian M.; Alleva, Jennifer L.; MacMillan, David W. C.

2013-01-01

The direct, asymmetric α-amination of aldehydes has been accomplished via a combination of photoredox and organocatalysis. Photon-generated, nitrogen-centered radicals undergo enantioselective α-addition to catalytically formed chiral enamines to directly produce stable α-amino aldehyde adducts bearing synthetically useful amine substitution patterns. Incorporation of a photolabile group on the amine precursor obviates the need to employ a photoredox catalyst in this transformation. Important...

Clinical characteristics in patients with asymmetric idiopathic pulmonary fibrosis.

Science.gov (United States)

Callahan, Sean J; Xia, Meng; Murray, Susan; Flaherty, Kevin R

2016-10-01

A group of patients with idiopathic pulmonary fibrosis (IPF) presents with disease affecting one lung markedly more than the other. At this time, it is unclear how this population differs from those who present with more symmetric disease. We sought to explain the characteristics of the asymmetric group and how their disease progresses. In this retrospective case-control study we accessed an interstitial lung disease (ILD) database and identified 14 asymmetric IPF cases via high-resolution computed tomography (HRCT) scoring of each lung lobe's disease severity. We identified 28 symmetric IPF controls from the same database using the same methods, and compared the clinical features of each group. Patients with asymmetric disease exhibited similar demographics as those in the general IPF population; they were predominantly male (64%), elderly (69 years old), and used tobacco (57%). We found a trend toward significantly increased all-cause mortality in the case population two years following diagnosis (p = 0.089). Pulmonary function tests were significantly lower in the case group at the time of diagnosis, then both groups experienced gradual decline. We found no statistically significant differences in number of IPF exacerbations (cases 43%, controls 39%, p = 0.824) and gastro-esophageal reflux (both groups 50%). Patients with asymmetric IPF resemble patients in the general IPF population but may have a lower overall survival rate. Further systemic factors may be studied to identify reasons for disease asymmetry and clinical decline in this population. Published by Elsevier Ltd.

Asymmetric Formal Aza-Diels-Alder Reaction of Trifluoromethyl Hemiaminals with Enones Catalyzed by Primary Amines.

Science.gov (United States)

Zhang, Sheng; Cha, Lide; Li, Lijun; Hu, Yanbin; Li, Yanan; Zha, Zhenggen; Wang, Zhiyong

2016-04-15

A primary amine-catalyzed asymmetric formal aza-Diels-Alder reaction of trifluoromethyl hemiaminals with enones was developed via a chiral gem-diamine intermediate. This novel protocol allowed facile access to structurally diverse trifluoromethyl-substituted piperidine scaffolds with high stereoselectivity. The utility of this method was further demonstrated through a concise approach to biologically active 4-hydroxypiperidine. More importantly, a stepwise mechanism involving an asymmetric induction process was proposed to rationalize the positive correlation between the chirality of the gem-diamine intermediate and the formal aza-Diels-Alder product.

Studies toward the asymmetric synthesis of the right part of the mycalamides.

Science.gov (United States)

Zhong, H Marlon; Sohn, Jeong-Hun; Rawal, Viresh H

2007-01-19

Described herein is the asymmetric synthesis of a functionalized, trioxadecalin unit that comprises the right-hand part of the mycalamides and related natural products. The synthetic route involves a 16-step sequence that accomplishes the formation of two heterocyclic rings and the generation of five stereocenters. The synthesis commenced with a C2-symmetric starting material, diethyl D-tartrate, and took advantage of a relay of diastereoselective reactions to extend this four-carbon chain and introduce new chiral centers. Subsequent electrophile-mediated cyclization afforded the desired pyran ring, which was then transformed into the desired, functionalized trioxadecalin skeleton.

Enantiopure N-Acyldihydropyridones as Synthetic Intermediates: Asymmetric Synthesis of (-)-Septicine and (-)-Tylophorine.

Science.gov (United States)

Comins, Daniel L.; Chen, Xinghai; Morgan, Lawrence A.

1997-10-17

A concise asymmetric synthesis of (-)-septicine (1) and (-)-tylophorine (2) was accomplished with a high degree of stereocontrol in eight and nine steps, respectively. Addition of 4-(1-butenyl)magnesium bromide to 1-acylpyridinium salt 3, prepared in situ from 4-methoxy-3-(triisopropylsilyl)pyridine and the chloroformate of (-)-trans-2-(alpha-cumyl)cyclohexanol, gave a 91% yield of diastereomerically pure dihydropyridone 7. Oxidative cleavage of 7 and subsequent reduction provided alcohol 6 in 81% yield. Conversion of 6 to the chloride followed by treatment with sodium methoxide gave indolizidinone 9 in high yield. Bromination and conjugate reduction of 9 with L-Selectride, and trapping the intermediate enolate with N-(5-chloro-2-pyridyl)triflimide, provided bromovinyl triflate 11. Palladium-catalyzed cross-coupling of excess (3,4-dimethoxyphenyl)zinc bromide and 11 gave (-)-septicine (1). On the basis of this synthesis, (-)-1 was assigned the Rconfiguration. Reaction of 1 with vanadium(V) trifluoride oxide in TFA/CH(2)Cl(2) effected oxidative coupling to give a 68% yield of (-)-tylophorine (2).

Coping with Asymmetric Channel Losses in CSMA/CA

DEFF Research Database (Denmark)

Paramanathan, Achuthan; Roetter, Daniel Enrique Lucani; Fitzek, Frank

2013-01-01

Inspired by the discrepancy between past theoretical analysis and real measurements for high-load scenarios for intersession network coding, we pinpoint and analyze the source of this discrepancy in wireless networks implementing a CSMA/CA medium access scheme. Our analysis shows that CSMA/CA is ......) confirm the sensitivity of the CSMA/CA scheme in real implementations, and (ii) shows that our adaptive protocol provides a simple, yet potent mechanism to cope with asymmetric channel losses and ultimately to enhance end-to-end throughput in high-load scenarios....

Does asymmetric correlation affect portfolio optimization?

Science.gov (United States)

Fryd, Lukas

2017-07-01

The classical portfolio optimization problem does not assume asymmetric behavior of relationship among asset returns. The existence of asymmetric response in correlation on the bad news could be important information in portfolio optimization. The paper applies Dynamic conditional correlation model (DCC) and his asymmetric version (ADCC) to propose asymmetric behavior of conditional correlation. We analyse asymmetric correlation among S&P index, bonds index and spot gold price before mortgage crisis in 2008. We evaluate forecast ability of the models during and after mortgage crisis and demonstrate the impact of asymmetric correlation on the reduction of portfolio variance.

Asymmetric Propagation Delay-Aware TDMA MAC Protocol for Mobile Underwater Acoustic Sensor Networks

Directory of Open Access Journals (Sweden)

A-Ra Cho

2018-06-01

Full Text Available The propagation delay in mobile underwater acoustic sensor network (MUASN is asymmetric because of its low sound propagation speed, and this asymmetry grows with the increase in packet travel time, which damages the collision avoidance mechanism of the spatial reuse medium access control (MAC protocols for MUASN. We propose an asymmetric propagation delay-aware time division multiple access (APD-TDMA for a MUASN in which periodic data packet transmission is required for a sink node (SN. Collisions at the SN are avoided by deferring data packet transmission after reception of a beacon packet from the SN, and data packets are arrived at the SN in a packet-train manner. The time-offset, which is the time for a node to wait before the transmission of a data packet after reception of a beacon packet, is determined by estimating the propagation delay over two consecutive cycles such that the idle interval at the SN is minimized, and this time-offset is announced by the beacon packet. Simulation results demonstrate that the APD-TDMA improves the channel access delay and the channel utilization by approximately 20% and 30%, respectively, compared with those of the block time bounded TDMA under the given network conditions.

Construction of an Asymmetric Quaternary Carbon Center via Allylation of Hydrazones

International Nuclear Information System (INIS)

Kim, Jin Bum; Satyender, Apuri; Jang, Doo Ok

2013-01-01

Asymmetric indium-mediated allylation of imine derivatives bearing a chiral auxiliary is a reliable strategy for the synthesis of chiral homoallylic amines. Various techniques for indium-mediated stereoselective allylation of imines bearing a chiral auxiliary have been reported. In 1997 Loh and co-workers reported indium-mediated allylation with imines derived from L-valine methyl ester. Since then, many forms of indium-mediated allylation bearing a chiral auxiliary have been reported, including imines derived from (S)-valinol, (R)-phenylglycinol, uracil, (R)-phenylglycinol methyl ester, N-tert-butanesufinamide, and (1R,2S)-1-amino-2-indanol. However, the synthesis of chiral auxiliaries often involves a laborious multi-step synthesis with expensive reagents. Therefore, the development of readily accessible chiral auxiliaries for asymmetric indium-mediated all-ylation is in high demand

Asymmetric cation-binding catalysis

DEFF Research Database (Denmark)

Oliveira, Maria Teresa; Lee, Jiwoong

2017-01-01

The employment of metal salts is quite limited in asymmetric catalysis, although it would provide an additional arsenal of safe and inexpensive reagents to create molecular functions with high optical purity. Cation chelation by polyethers increases the salts' solubility in conventional organic...... solvents, thus increasing their applicability in synthesis. The expansion of this concept to chiral polyethers led to the emergence of asymmetric cation-binding catalysis, where chiral counter anions are generated from metal salts, particularly using BINOL-based polyethers. Alkali metal salts, namely KF...... highly enantioselective silylation reactions in polyether-generated chiral environments, and leading to a record-high turnover in asymmetric organocatalysis. This can lead to further applications by the asymmetric use of other inorganic salts in various organic transformations....

Rhabdomyolysis and Renal Insufficiency Due to Synthetic Cannabinoid Intoxication

Directory of Open Access Journals (Sweden)

Semiha Orhan

2017-12-01

Full Text Available Bonsai is the street name of synthetic marijuana, which is a psychoactive substance. Since synthetic cannabinoids are easily accessible and cheap, their use is becoming widespread day by day. It can cause not only various clinical symptoms but also severe rhabdomyolysis. In this case, with severe rhabdomyolysis, we tried to discuss the treatment challenges of the patient examined in intensive care unit with the history of bonsai use.

Asymmetric Total Synthesis of Four Stereoisomers of the Sex Pheromone of the Western Corn Rootworm

Directory of Open Access Journals (Sweden)

Zhi-Feng Sun

2018-03-01

Full Text Available A convergent synthesis of four stereoisomers of the sex pheromone of the western corn rootworm (8-methyldecan-2-yl propionate, 1 from commercially available chiral starting materials is reported. The key step was Julia–Kocienski olefination between chiral BT-sulfone and chiral aldehyde. This synthetic route provided the four stereoisomers of 1 in 24–29% total yield via a six-step sequence. The simple scale-up strategy provides a new way to achieve the asymmetric synthesis of the sex pheromone.

Synthetic biology between technoscience and thing knowledge.

Science.gov (United States)

Gelfert, Axel

2013-06-01

Synthetic biology presents a challenge to traditional accounts of biology: Whereas traditional biology emphasizes the evolvability, variability, and heterogeneity of living organisms, synthetic biology envisions a future of homogeneous, humanly engineered biological systems that may be combined in modular fashion. The present paper approaches this challenge from the perspective of the epistemology of technoscience. In particular, it is argued that synthetic-biological artifacts lend themselves to an analysis in terms of what has been called 'thing knowledge'. As such, they should neither be regarded as the simple outcome of applying theoretical knowledge and engineering principles to specific technological problems, nor should they be treated as mere sources of new evidence in the general pursuit of scientific understanding. Instead, synthetic-biological artifacts should be viewed as partly autonomous research objects which, qua their material-biological constitution, embody knowledge about the natural world-knowledge that, in turn, can be accessed via continuous experimental interrogation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Specifications of Standards in Systems and Synthetic Biology.

Science.gov (United States)

Schreiber, Falk; Bader, Gary D; Golebiewski, Martin; Hucka, Michael; Kormeier, Benjamin; Le Novère, Nicolas; Myers, Chris; Nickerson, David; Sommer, Björn; Waltemath, Dagmar; Weise, Stephan

2015-09-04

Standards shape our everyday life. From nuts and bolts to electronic devices and technological processes, standardised products and processes are all around us. Standards have technological and economic benefits, such as making information exchange, production, and services more efficient. However, novel, innovative areas often either lack proper standards, or documents about standards in these areas are not available from a centralised platform or formal body (such as the International Standardisation Organisation). Systems and synthetic biology is a relatively novel area, and it is only in the last decade that the standardisation of data, information, and models related to systems and synthetic biology has become a community-wide effort. Several open standards have been established and are under continuous development as a community initiative. COMBINE, the ‘COmputational Modeling in BIology’ NEtwork has been established as an umbrella initiative to coordinate and promote the development of the various community standards and formats for computational models. There are yearly two meeting, HARMONY (Hackathons on Resources for Modeling in Biology), Hackathon-type meetings with a focus on development of the support for standards, and COMBINE forums, workshop-style events with oral presentations, discussion, poster, and breakout sessions for further developing the standards. For more information see http://co.mbine.org/. So far the different standards were published and made accessible through the standards’ web- pages or preprint services. The aim of this special issue is to provide a single, easily accessible and citable platform for the publication of standards in systems and synthetic biology. This special issue is intended to serve as a central access point to standards and related initiatives in systems and synthetic biology, it will be published annually to provide an opportunity for standard development groups to communicate updated specifications.

Charge Asymmetric Cosmic Rays as a probe of Flavor Violating Asymmetric Dark Matter

DEFF Research Database (Denmark)

Masina, Isabella; Sannino, Francesco

2011-01-01

The recently introduced cosmic sum rules combine the data from PAMELA and Fermi-LAT cosmic ray experiments in a way that permits to neatly investigate whether the experimentally observed lepton excesses violate charge symmetry. One can in a simple way determine universal properties of the unknown...... component of the cosmic rays. Here we attribute a potential charge asymmetry to the dark sector. In particular we provide models of asymmetric dark matter able to produce charge asymmetric cosmic rays. We consider spin zero, spin one and spin one-half decaying dark matter candidates. We show that lepton...... flavor violation and asymmetric dark matter are both required to have a charge asymmetry in the cosmic ray lepton excesses. Therefore, an experimental evidence of charge asymmetry in the cosmic ray lepton excesses implies that dark matter is asymmetric....

Strategic communication and behavioral coupling in asymmetric joint action

DEFF Research Database (Denmark)

Vesper, Cordula; Richardson, Michael J.

2014-01-01

How is coordination achieved in asymmetric joint actions where co-actors have unequal access to task information? Pairs of participants performed a non-verbal tapping task with the goal of synchronizing taps to different targets. We tested whether ‘Leaders’ knowing the target locations would...... support ‘Followers’ without this information. Experiment 1 showed that Leaders tapped with higher amplitude that also scaled with specific target distance, thereby emphasizing differences between correct targets and possible alternatives. This strategic communication only occurred when Leaders’ movements...

Cyclodextrins in Asymmetric and Stereospecific Synthesis

Directory of Open Access Journals (Sweden)

Fliur Macaev

2015-09-01

Full Text Available Since their discovery, cyclodextrins have widely been used as green and easily available alternatives to promoters or catalysts of different chemical reactions in water. This review covers the research and application of cyclodextrins and their derivatives in asymmetric and stereospecific syntheses, with their division into three main groups: (1 cyclodextrins promoting asymmetric and stereospecific catalysis in water; (2 cyclodextrins’ complexes with transition metals as asymmetric and stereospecific catalysts; and (3 cyclodextrins’ non-metallic derivatives as asymmetric and stereospecific catalysts. The scope of this review is to systematize existing information on the contribution of cyclodextrins to asymmetric and stereospecific synthesis and, thus, to facilitate further development in this direction.

Principles of asymmetric synthesis

CERN Document Server

Gawley, Robert E; Aube, Jeffrey

2012-01-01

The world is chiral. Most of the molecules in it are chiral, and asymmetric synthesis is an important means by which enantiopure chiral molecules may be obtained for study and sale. Using examples from the literature of asymmetric synthesis, this book presents a detailed analysis of the factors that govern stereoselectivity in organic reactions. After an explanation of the basic physical-organic principles governing stereoselective reactions, the authors provide a detailed, annotated glossary of stereochemical terms. A chapter on "Practical Aspects of Asymmetric Synthesis" provides a critical overview of the most common methods for the preparation of enantiomerically pure compounds, techniques for analysis of stereoisomers using chromatographic, spectroscopic, and chiroptical methods. The authors then present an overview of the most important methods in contemporary asymmetric synthesis organized by reaction type. Thus, there are four chapters on carbon-carbon bond forming reactions, one chapter on reductions...

Realistic Vendor-Specific Synthetic Ultrasound Data for Quality Assurance of 2-D Speckle Tracking Echocardiography: Simulation Pipeline and Open Access Database.

Science.gov (United States)

Alessandrini, Martino; Chakraborty, Bidisha; Heyde, Brecht; Bernard, Olivier; De Craene, Mathieu; Sermesant, Maxime; D'Hooge, Jan

2018-03-01

Two-dimensional (2-D) echocardiography is the modality of choice in the clinic for the diagnosis of cardiac disease. Hereto, speckle tracking (ST) packages complement visual assessment by the cardiologist by providing quantitative diagnostic markers of global and regional cardiac function (e.g., displacement, strain, and strain-rate). Yet, the reported high vendor-dependence between the outputs of different ST packages raises clinical concern and hampers the widespread dissemination of the ST technology. In part, this is due to the lack of a solid commonly accepted quality assurance pipeline for ST packages. Recently, we have developed a framework to benchmark ST algorithms for 3-D echocardiography by using realistic simulated volumetric echocardiographic recordings. Yet, 3-D echocardiography remains an emerging technology, whereas the compelling clinical concern is, so far, directed to the standardization of 2-D ST only. Therefore, by building upon our previous work, we present in this paper a pipeline to generate realistic synthetic sequences for 2-D ST algorithms. Hereto, the synthetic cardiac motion is obtained from a complex electromechanical heart model, whereas realistic vendor-specific texture is obtained by sampling a real clinical ultrasound recording. By modifying the parameters in our pipeline, we generated an open-access library of 105 synthetic sequences encompassing: 1) healthy and ischemic motion patterns; 2) the most common apical probe orientations; and 3) vendor-specific image quality from seven different systems. Ground truth deformation is also provided to allow performance analysis. The application of the provided data set is also demonstrated in the benchmarking of a recent academic ST algorithm.

Synthetic Jets Flow Control on a vertical stabilizer

Science.gov (United States)

Rathay, Nicholas; Boucher, Matthew; Amitay, Michael

2011-11-01

The vertical stabilizer on most commercial transport aircraft is much larger than required for stability and control. The tail is significantly oversized in order to maintain controllability in the event of asymmetric engine failure and meet flying qualities requirements related to dynamic motion. Using aerodynamic flow control techniques, it may be possible to reduce the size of the tail while maintaining similar control authority during inclement flight conditions. Reducing the size of the tail decreases the weight and the drag of the airplane, which results in considerable savings in fuel costs. In this work, it is shown that synthetic jet (zero-net-mass-flux) actuators are capable of reattaching the separated flow on the rudder and augmenting the performance of the stabilizer. Experiments were conducted in an open-return wind tunnel on a 1/25th scale model of a vertical stabilizer and a partial fuselage section. The surface pressure, aerodynamic loads and data acquired with a Stereo PIV system were used to investigate the effectiveness of this technology as well as provide a more detailed analysis of the flowfield and showed that the synthetic jets are capable of augmenting the side-force by up to 20%.

Asymmetric monometallic nanorod nanoparticle dimer and related compositions and methods

KAUST Repository

Han, Yu

2016-03-31

The fabrication of asymmetric monometallic nanocrystals with novel properties for plasmonics, nanophotonics and nanoelectronics. Asymmetric monometallic plasmonic nanocrystals are of both fundamental synthetic challenge and practical significance. In an example, a thiol-ligand mediated growth strategy that enables the synthesis of unprecedented Au Nanorod-Au Nanoparticle (AuNR-AuNP) dimers from pre-synthesized AuNR seeds. Using high-resolution electron microscopy and tomography, crystal structure and three-dimensional morphology of the dimer, as well as the growth pathway of the AuNP on the AuNR seed, was investigated for this example. The dimer exhibits an extraordinary broadband optical extinction spectrum spanning the UV, visible, and near infrared regions (300 - 1300 nm). This unexpected property makes the AuNR-AuNP dimer example useful for many nanophotonic applications. In two experiments, the dimer example was tested as a surface- enhanced Raman scattering (SERS) substrate and a solar light harvester for photothermal conversion, in comparison with the mixture of AuNR and AuNP. In the SERS experiment, the dimer example showed an enhancement factor about 10 times higher than that of the mixture, when the excitation wavelength (660 nm) was off the two surface plasmon resonance (SPR) bands of the mixture. In the photothermal conversion experiment under simulated sunlight illumination, the dimer example exhibited an energy conversion efficiency about 1.4 times as high as that of the mixture.

Polystyrene-supported cu(II)-R-Box as recyclable catalyst in asymmetric Friedel–Crafts reaction

KAUST Repository

Desyatkin, V. G.

2017-02-12

The complex of copper(II) trifluoromethanesulfonate with chiral isopropyl bis(oxazoline) ligand (i-Pr-Box) was immobilized on accessible and inexpensive Merrifield resin according to a “click” procedure. The resulting catalyst showed high efficiency and recyclability in the asymmetric Friedel–Crafts alkylation of indole and its derivatives. The catalyst can be recycled five times without appreciable loss in activity and enantioselectivity.

Polystyrene-supported cu(II)-R-Box as recyclable catalyst in asymmetric Friedel–Crafts reaction

KAUST Repository

Desyatkin, V. G.; Anokhin, M. V.; Rodionov, Valentin; Beletskaya, I. P.

2017-01-01

The complex of copper(II) trifluoromethanesulfonate with chiral isopropyl bis(oxazoline) ligand (i-Pr-Box) was immobilized on accessible and inexpensive Merrifield resin according to a “click” procedure. The resulting catalyst showed high efficiency and recyclability in the asymmetric Friedel–Crafts alkylation of indole and its derivatives. The catalyst can be recycled five times without appreciable loss in activity and enantioselectivity.

Asymmetric positive feedback loops reliably control biological responses.

Science.gov (United States)

Ratushny, Alexander V; Saleem, Ramsey A; Sitko, Katherine; Ramsey, Stephen A; Aitchison, John D

2012-04-24

Positive feedback is a common mechanism enabling biological systems to respond to stimuli in a switch-like manner. Such systems are often characterized by the requisite formation of a heterodimer where only one of the pair is subject to feedback. This ASymmetric Self-UpREgulation (ASSURE) motif is central to many biological systems, including cholesterol homeostasis (LXRα/RXRα), adipocyte differentiation (PPARγ/RXRα), development and differentiation (RAR/RXR), myogenesis (MyoD/E12) and cellular antiviral defense (IRF3/IRF7). To understand why this motif is so prevalent, we examined its properties in an evolutionarily conserved transcriptional regulatory network in yeast (Oaf1p/Pip2p). We demonstrate that the asymmetry in positive feedback confers a competitive advantage and allows the system to robustly increase its responsiveness while precisely tuning the response to a consistent level in the presence of varying stimuli. This study reveals evolutionary advantages for the ASSURE motif, and mechanisms for control, that are relevant to pharmacologic intervention and synthetic biology applications.

Asymmetric Evolutionary Games

Science.gov (United States)

McAvoy, Alex; Hauert, Christoph

2015-01-01

Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner’s Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games. PMID:26308326

Asymmetrical field emitter

Science.gov (United States)

Fleming, J.G.; Smith, B.K.

1995-10-10

A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

The influence of variability on the optimal shape of an airway tree branching asymmetrically

International Nuclear Information System (INIS)

Mauroy, Benjamin; Bokov, Plamen

2010-01-01

The asymmetry of the bronchial tree has been reported on numerous occasions, and bronchi in the lung bifurcate most of the time into a major and a minor daughter. Asymmetry is most probably bound to play a role on the hydrodynamic resistance and volume occupation of the bronchial tree. Thus, in this work, we search for an optimal asymmetric airway tree crossed by Poiseuille flow that would be a good candidate to model the distal conductive part of the lung. The geometry is controlled by major and minor diameter reduction factors that depend on the generation. We show that the optimal asymmetric tree has diameter reduction factors that are adimensional from the second level of bifurcation and that they are highly dependent on the asymmetric ratio that defines the relative sizes of the major and minor branches in a bifurcation. This optimization also gives access to a cost function whose particularity is to be asymmetric around its minimum. Thus, the cliff-edge hypothesis predicts that if the system suffers variability, then the best tree is shifted from the optimal. We apply a recent theoretical model of cliff-edge in order to measure the role of variability on the determination of the best asymmetric tree. Then, we compare our results with lung data of the literature. In particular, we are able to quantify the variability needed to fit the data and to give hypothesis that could explain, at least partially, the shift found between the optimal tree and the measures in the case of asymmetric bronchial trees. Finally, our model predicts that, even if the population is adapted at best, there always exist individuals whose bronchial trees are associated with larger costs comparatively to the average and who ought to be more sensitive to geometrical remodeling

Cinchona alkaloids in asymmetric organocatalysis

NARCIS (Netherlands)

Marcelli, T.; Hiemstra, H.

2010-01-01

This article reviews the applications of cinchona alkaloids as asymmetric catalysts. In the last few years, characterized by the resurgence of interest in asymmetric organocatalysis, cinchona derivatives have been shown to catalyze an outstanding array of chemical reactions, often with remarkable

Synthetic biology, inspired by synthetic chemistry.

Science.gov (United States)

Malinova, V; Nallani, M; Meier, W P; Sinner, E K

2012-07-16

The topic synthetic biology appears still as an 'empty basket to be filled'. However, there is already plenty of claims and visions, as well as convincing research strategies about the theme of synthetic biology. First of all, synthetic biology seems to be about the engineering of biology - about bottom-up and top-down approaches, compromising complexity versus stability of artificial architectures, relevant in biology. Synthetic biology accounts for heterogeneous approaches towards minimal and even artificial life, the engineering of biochemical pathways on the organismic level, the modelling of molecular processes and finally, the combination of synthetic with nature-derived materials and architectural concepts, such as a cellular membrane. Still, synthetic biology is a discipline, which embraces interdisciplinary attempts in order to have a profound, scientific base to enable the re-design of nature and to compose architectures and processes with man-made matter. We like to give an overview about the developments in the field of synthetic biology, regarding polymer-based analogs of cellular membranes and what questions can be answered by applying synthetic polymer science towards the smallest unit in life, namely a cell. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Manipulating novel quantum phenomena using synthetic gauge fields

Science.gov (United States)

Zhang, Shao-Liang; Zhou, Qi

2017-11-01

The past few years have seen fascinating progress in the creation and utilization of synthetic gauge fields for charge-neutral ultracold atoms. Whereas the synthesis of gauge fields in itself is readily interesting, it is more exciting to explore the new era that will be brought by the interplay between synthetic gauge fields and many other degrees of freedom of highly tunable ultracold atoms. This topical review surveys recent developments in using synthetic gauge fields to manipulate novel quantum phenomena that are not easy to access in other systems. We first summarize current experimental methods of creating synthetic gauge fields, including the use of Raman schemes, shaken lattices, and Raman-dressed lattices. We then discuss how synthetic gauge fields bring new physics to non-interacting systems, including degenerate single-particle ground states, quartic dispersions, topological band structures in lattices, and synthetic dimensions. As for interacting systems, we focus on novel quantum many-body states and quantum macroscopic phenomena induced by interactions in the presence of unconventional single-particle dispersions. For bosons, we discuss how a quartic dispersion leads to non-condensed bosonic states at low temperatures and at the ground state. For fermions, we discuss chiral superfluids in the presence of attractive s-wave interaction, where high partial-wave interactions are not required. Finally, we discuss the challenges in current experiments, and conclude with an outlook for what new exciting developments synthetic gauge fields may bring us in the near future.

Alternative Asymmetric Stochastic Volatility Models

NARCIS (Netherlands)

M. Asai (Manabu); M.J. McAleer (Michael)

2010-01-01

textabstractThe stochastic volatility model usually incorporates asymmetric effects by introducing the negative correlation between the innovations in returns and volatility. In this paper, we propose a new asymmetric stochastic volatility model, based on the leverage and size effects. The model is

Asymmetric ion trap

Science.gov (United States)

Barlow, Stephan E.; Alexander, Michael L.; Follansbee, James C.

1997-01-01

An ion trap having two end cap electrodes disposed asymmetrically about a center of a ring electrode. The inner surface of the end cap electrodes are conformed to an asymmetric pair of equipotential lines of the harmonic formed by the application of voltages to the electrodes. The asymmetry of the end cap electrodes allows ejection of charged species through the closer of the two electrodes which in turn allows for simultaneously detecting anions and cations expelled from the ion trap through the use of two detectors charged with opposite polarity.

Key role of asymmetric interactions in low-dimensional heat transport

International Nuclear Information System (INIS)

Chen, Shunda; Zhang, Yong; Wang, Jiao; Zhao, Hong

2016-01-01

We study the heat current autocorrelation function (HCAF) in one-dimensional, momentum-conserving lattices. In particular, we explore if there is any link between the decaying characteristics of the HCAF and asymmetric interparticle interactions. The Lennard-Jones model is investigated intensively in view of its significance to applications. It is found that, in the time range accessible to numerical simulations, the HCAF decays faster than power-law manners, and in some cases it decays even exponentially. Following the Green–Kubo formula, fast decay of the HCAF implies convergence of the heat conductivity, which is also corroborated by simulations. In addition, with a comparison to the Fermi–Pasta–Ulam-β model of symmetric interactions, the HCAF of the Fermi–Pasta–Ulam-α–β model of asymmetric interactions is also investigated. The results of all these studies lead to that, in certain ranges of parameters, fast decaying of the HCAF can be observed and correlated to the asymmetry degree of interactions. (paper: classical statistical mechanics, equilibrium and non-equilibrium)

Thiophenyl-substituted triazolyl-thione L-alanine: asymmetric synthesis, aggregation and biological properties.

Science.gov (United States)

Saghyan, Ashot S; Simonyan, Hayarpi M; Petrosyan, Satenik G; Geolchanyan, Arpine V; Roviello, Giovanni N; Musumeci, Domenica; Roviello, Valentina

2014-10-01

In this work, we report the asymmetric synthesis and characterization of an artificial amino acid based on triazolyl-thione L-alanine, which was modified with a thiophenyl-substituted moiety, as well as in vitro studies of its nucleic acid-binding ability. We found, by dynamic light scattering studies, that the synthetic amino acid was able to form supramolecular aggregates having a hydrodynamic diameter higher than 200 nm. Furthermore, we demonstrated, by UV and CD experiments, that the heteroaromatic amino acid, whose enzymatic stability was demonstrated by HPLC analysis also after 24 h of incubation in human serum, was able to bind a RNA complex, which is a feature of biomedical interest in view of innovative antiviral strategies based on modulation of RNA-RNA molecular recognition.

Worst Asymmetrical Short-Circuit Current

DEFF Research Database (Denmark)

Arana Aristi, Iván; Holmstrøm, O; Grastrup, L

2010-01-01

In a typical power plant, the production scenario and the short-circuit time were found for the worst asymmetrical short-circuit current. Then, a sensitivity analysis on the missing generator values was realized in order to minimize the uncertainty of the results. Afterward the worst asymmetrical...

Inclined asymmetric librations in exterior resonances

Science.gov (United States)

Voyatzis, G.; Tsiganis, K.; Antoniadou, K. I.

2018-04-01

Librational motion in Celestial Mechanics is generally associated with the existence of stable resonant configurations and signified by the existence of stable periodic solutions and oscillation of critical (resonant) angles. When such an oscillation takes place around a value different than 0 or π , the libration is called asymmetric. In the context of the planar circular restricted three-body problem, asymmetric librations have been identified for the exterior mean motion resonances (MMRs) 1:2, 1:3, etc., as well as for co-orbital motion (1:1). In exterior MMRs the massless body is the outer one. In this paper, we study asymmetric librations in the three-dimensional space. We employ the computational approach of Markellos (Mon Not R Astron Soc 184:273-281, https://doi.org/10.1093/mnras/184.2.273, 1978) and compute families of asymmetric periodic orbits and their stability. Stable asymmetric periodic orbits are surrounded in phase space by domains of initial conditions which correspond to stable evolution and librating resonant angles. Our computations were focused on the spatial circular restricted three-body model of the Sun-Neptune-TNO system (TNO = trans-Neptunian object). We compare our results with numerical integrations of observed TNOs, which reveal that some of them perform 1:2 resonant, inclined asymmetric librations. For the stable 1:2 TNO librators, we find that their libration seems to be related to the vertically stable planar asymmetric orbits of our model, rather than the three-dimensional ones found in the present study.

Reversal modes in asymmetric Ni nanowires

Energy Technology Data Exchange (ETDEWEB)

Leighton, B.; Pereira, A. [Departamento de Fisica, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Escrig, J., E-mail: jescrigm@gmail.com [Departamento de Fisica, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Avda. Ecuador 3493, 917-0124 Santiago (Chile)

2012-11-15

We have investigated the evolution of the magnetization reversal mechanism in asymmetric Ni nanowires as a function of their geometry. Circular nanowires are found to reverse their magnetization by the propagation of a vortex domain wall, while in very asymmetric nanowires the reversal is driven by the propagation of a transverse domain wall. The effect of shape asymmetry of the wire on coercivity and remanence is also studied. Angular dependence of the remanence and coercivity is also addressed. Tailoring the magnetization reversal mechanism in asymmetric nanowires can be useful for magnetic logic and race-track memory, both of which are based on the displacement of magnetic domain walls. Finally, an alternative method to detect the presence of magnetic drops is proposed. - Highlights: Black-Right-Pointing-Pointer Asymmetry strongly modifies the magnetic behavior of a wire. Black-Right-Pointing-Pointer Very asymmetric nanowires reverse their magnetization by a transverse domain wall. Black-Right-Pointing-Pointer An alternative method to detect the presence of magnetic drops is proposed. Black-Right-Pointing-Pointer Tailoring the reversal mode in asymmetric nanowires can be useful for potential applications.

Asymmetric cryptography based on wavefront sensing.

Science.gov (United States)

Peng, Xiang; Wei, Hengzheng; Zhang, Peng

2006-12-15

A system of asymmetric cryptography based on wavefront sensing (ACWS) is proposed for the first time to our knowledge. One of the most significant features of the asymmetric cryptography is that a trapdoor one-way function is required and constructed by analogy to wavefront sensing, in which the public key may be derived from optical parameters, such as the wavelength or the focal length, while the private key may be obtained from a kind of regular point array. The ciphertext is generated by the encoded wavefront and represented with an irregular array. In such an ACWS system, the encryption key is not identical to the decryption key, which is another important feature of an asymmetric cryptographic system. The processes of asymmetric encryption and decryption are formulized mathematically and demonstrated with a set of numerical experiments.

Experimental demonstration of 2.5 Gbit/S incoherent two-dimensional optical code division multiple access system

International Nuclear Information System (INIS)

Glesk, I.; Baby, V.; Bres, C.-S.; Xu, L.; Rand, D.; Prucnal, P.R.

2004-01-01

We demonstrated error-free operation of 4 simultaneous users in a fast frequency-hopping time-spreading optical code division multiple access system operating at 2.5 Gbit/s a Star architecture. Effective power penalty was ≤0.5dB. Novel optical code division multiple access receiver based on Terahertz Optical Asymmetric Demultiplexer was demonstrated to eliminate multiple access interference (Authors)

Asymmetric regulation measures in the European gas sector

International Nuclear Information System (INIS)

Clastres, C.

2003-01-01

Like most of the privatized utilities, the gas market needs to be regulated in order for the positive benefits of competition to fully develop. In addition to the issues of eligibility and access, the regulators have had to deal with several other obstacles, and among other things have raised questions concerning the supply of gas. Asymmetric regulation (release gas and market share reduction measures) is one of the possible responses, making it possible to facilitate access to both resources and consumers. The British regulator was the first to introduce this type of regulation during the 1990's. More recently, Spain and Italy have also adopted it. Although we can find a number of similarities in the causes justifying the use of such regulation, the results obtained vary from one country to another. It appears that they are dependent upon a number of variables including: the existence of national production, the structure of the gas market and finally the level of penetration and growth of gas in various business sectors. (authors)

The adjuvant potential of synthetic alkylglycerols.

Science.gov (United States)

Acevedo, Reinaldo; Gil, Danay; del Campo, Judith; Bracho, Gustavo; Valdés, Yolanda; Pérez, Oliver

2006-04-12

Alkylglycerols (AGs) have shown immune stimulant and adjuvant activity in many studies, but natural sources are not so accessible and their extraction from them is very complicated. Therefore, a group of chemists at IFAL have synthesized AG analogs. The aim of this work was to evaluate the adjuvant potential of different synthetic AGs. A mix of ovoalbumin (Ova) and AGs increase anti-Ova IgG antibodies production in sera of immunized mice. The predominant subclass was IgG1 although higher levels of IgG2a were observed as the carbon chain length of AGs increased. AGs also induced the production of IL-12 and nitric oxide (NO) in the U937 human histiocyte and J774 mouse macrophage cell lines, respectively. These results indicate that synthetic AGs are effective adjuvants for the standardized antigen, Ova.

Quantifying social asymmetric structures.

Science.gov (United States)

Solanas, Antonio; Salafranca, Lluís; Riba, Carles; Sierra, Vicenta; Leiva, David

2006-08-01

Many social phenomena involve a set of dyadic relations among agents whose actions may be dependent. Although individualistic approaches have frequently been applied to analyze social processes, these are not generally concerned with dyadic relations, nor do they deal with dependency. This article describes a mathematical procedure for analyzing dyadic interactions in a social system. The proposed method consists mainly of decomposing asymmetric data into their symmetric and skew-symmetric parts. A quantification of skew symmetry for a social system can be obtained by dividing the norm of the skew-symmetric matrix by the norm of the asymmetric matrix. This calculation makes available to researchers a quantity related to the amount of dyadic reciprocity. With regard to agents, the procedure enables researchers to identify those whose behavior is asymmetric with respect to all agents. It is also possible to derive symmetric measurements among agents and to use multivariate statistical techniques.

pClone: Synthetic Biology Tool Makes Promoter Research Accessible to Beginning Biology Students

Science.gov (United States)

Campbell, A. Malcolm; Eckdahl, Todd; Cronk, Brian; Andresen, Corinne; Frederick, Paul; Huckuntod, Samantha; Shinneman, Claire; Wacker, Annie; Yuan, Jason

2014-01-01

The "Vision and Change" report recommended genuine research experiences for undergraduate biology students. Authentic research improves science education, increases the number of scientifically literate citizens, and encourages students to pursue research. Synthetic biology is well suited for undergraduate research and is a growing area…

Designing asymmetric multiferroics with strong magnetoelectric coupling

Science.gov (United States)

Lu, Xuezeng; Xiang, Hongjun; Rondinelli, James; Materials Theory; Design Group Team

2015-03-01

Multiferroics offer exciting opportunities for electric-field control of magnetism. Single-phase multiferroics suitable for such applications at room temperature need much more study. Here, we propose the concept of an alternative type of multiferroics, namely, the ``asymmetric multiferroic.'' In asymmetric multiferroics, two locally stable ferroelectric states are not symmetrically equivalent, leading to different magnetic properties between these two states. Furthermore, we predict from first principles that a Fe-Cr-Mo superlattice with the LiNbO3-type structure is such an asymmetric multiferroic. The strong ferrimagnetism, high ferroelectric polarization, and significant dependence of the magnetic transition temperature on polarization make this asymmetric multiferroic an ideal candidate for realizing electric-field control of magnetism at room temperature. Our study suggests that the asymmetric multiferroic may provide an alternative playground for voltage control of magnetism and find its applications in spintronics and quantum computing.

Chaos of several typical asymmetric systems

International Nuclear Information System (INIS)

Feng Jingjing; Zhang Qichang; Wang Wei

2012-01-01

The threshold for the onset of chaos in asymmetric nonlinear dynamic systems can be determined using an extended Padé method. In this paper, a double-well asymmetric potential system with damping under external periodic excitation is investigated, as well as an asymmetric triple-well potential system under external and parametric excitation. The integrals of Melnikov functions are established to demonstrate that the motion is chaotic. Threshold values are acquired when homoclinic and heteroclinic bifurcations occur. The results of analytical and numerical integration are compared to verify the effectiveness and feasibility of the analytical method.

Eight new genomes and synthetic controls increase the accessibility of rapid melt-MAMA SNP typing of Coxiella burnetii.

Directory of Open Access Journals (Sweden)

Edvin Karlsson

Full Text Available The case rate of Q fever in Europe has increased dramatically in recent years, mainly because of an epidemic in the Netherlands in 2009. Consequently, there is a need for more extensive genetic characterization of the disease agent Coxiella burnetii in order to better understand the epidemiology and spread of this disease. Genome reference data are essential for this purpose, but only thirteen genome sequences are currently available. Current methods for typing C. burnetii are criticized for having problems in comparing results across laboratories, require the use of genomic control DNA, and/or rely on markers in highly variable regions. We developed in this work a method for single nucleotide polymorphism (SNP typing of C. burnetii isolates and tissue samples based on new assays targeting ten phylogenetically stable synonymous canonical SNPs (canSNPs. These canSNPs represent previously known phylogenetic branches and were here identified from sequence comparisons of twenty-one C. burnetii genomes, eight of which were sequenced in this work. Importantly, synthetic control templates were developed, to make the method useful to laboratories lacking genomic control DNA. An analysis of twenty-one C. burnetii genomes confirmed that the species exhibits high sequence identity. Most of its SNPs (7,493/7,559 shared by >1 genome follow a clonal inheritance pattern and are therefore stable phylogenetic typing markers. The assays were validated using twenty-six genetically diverse C. burnetii isolates and three tissue samples from small ruminants infected during the epidemic in the Netherlands. Each sample was assigned to a clade. Synthetic controls (vector and PCR amplified gave identical results compared to the corresponding genomic controls and are viable alternatives to genomic DNA. The results from the described method indicate that it could be useful for cheap and rapid disease source tracking at non-specialized laboratories, which requires accurate

Admission Control of Integrated Voice and Data CDMA／TDD System Considering Asymmetric Traffic and Power Limit

Institute of Scientific and Technical Information of China (English)

CAOYanbo; ZHOUBin; LIChengshu

2004-01-01

In this paper, we research an admission control scheme of integrated voice and data CDMA/TDD (Code division multiple access/Time division duplex) system considering asymmetric traffic and power limit. A new user can access the system only if the outage probabilities it experiences on the uplink and downlink time slots are below a threshold value. Based on the power limit the results show the voice and data blocking probabilities under different cell coverage~ arrival rates and various uplink/downlink time slot allocation patterns. Furthermore, multicode and multislot schemes are also evaluated under the presented admission control scheme.

Congenital asymmetric crying face: a case report

Directory of Open Access Journals (Sweden)

Semra Kara

2011-12-01

Full Text Available Congenital asymmetric crying face is an anomalia caused by unilateral absence or weakness of depressor anguli oris muscle The major finding of the disease is the absence or weakness in the outer and lower movement of the commissure during crying. The other expression muscles are normal and the face is symmetric at rest. The asymmetry in congenital asymmetric crying face is most evident during infancy but decreases by age. Congenital asymmetric crying face can be associated with cervicofacial, musclebone, respiratory, genitourinary and central nervous system anomalia. It is diagnosed by physical examination. This paper presents a six days old infant with Congenital asymmetric crying face and discusses the case in terms of diagnosis and disease features.

Robust generative asymmetric GMM for brain MR image segmentation.

Science.gov (United States)

Ji, Zexuan; Xia, Yong; Zheng, Yuhui

2017-11-01

Accurate segmentation of brain tissues from magnetic resonance (MR) images based on the unsupervised statistical models such as Gaussian mixture model (GMM) has been widely studied during last decades. However, most GMM based segmentation methods suffer from limited accuracy due to the influences of noise and intensity inhomogeneity in brain MR images. To further improve the accuracy for brain MR image segmentation, this paper presents a Robust Generative Asymmetric GMM (RGAGMM) for simultaneous brain MR image segmentation and intensity inhomogeneity correction. First, we develop an asymmetric distribution to fit the data shapes, and thus construct a spatial constrained asymmetric model. Then, we incorporate two pseudo-likelihood quantities and bias field estimation into the model's log-likelihood, aiming to exploit the neighboring priors of within-cluster and between-cluster and to alleviate the impact of intensity inhomogeneity, respectively. Finally, an expectation maximization algorithm is derived to iteratively maximize the approximation of the data log-likelihood function to overcome the intensity inhomogeneity in the image and segment the brain MR images simultaneously. To demonstrate the performances of the proposed algorithm, we first applied the proposed algorithm to a synthetic brain MR image to show the intermediate illustrations and the estimated distribution of the proposed algorithm. The next group of experiments is carried out in clinical 3T-weighted brain MR images which contain quite serious intensity inhomogeneity and noise. Then we quantitatively compare our algorithm to state-of-the-art segmentation approaches by using Dice coefficient (DC) on benchmark images obtained from IBSR and BrainWeb with different level of noise and intensity inhomogeneity. The comparison results on various brain MR images demonstrate the superior performances of the proposed algorithm in dealing with the noise and intensity inhomogeneity. In this paper, the RGAGMM

Natural - synthetic - artificial!

DEFF Research Database (Denmark)

Nielsen, Peter E

2010-01-01

The terms "natural," "synthetic" and "artificial" are discussed in relation to synthetic and artificial chromosomes and genomes, synthetic and artificial cells and artificial life.......The terms "natural," "synthetic" and "artificial" are discussed in relation to synthetic and artificial chromosomes and genomes, synthetic and artificial cells and artificial life....

Extensible Synthetic File Servers? or: Structuring the Glue between Tester and System Under Test

NARCIS (Netherlands)

Belinfante, Axel; Mullender, Sape J.; Collyer, G.

2007-01-01

We discuss a few simple scenarios of how we can design and develop a compositional synthetic ��?le server that gives access to external processes – in particular, in the context of testing, gives access to the system under test – such that certain parts of said synthethic ��?le server can be

Dynamic JUNQ inclusion bodies are asymmetrically inherited in mammalian cell lines through the asymmetric partitioning of vimentin.

Science.gov (United States)

Ogrodnik, Mikołaj; Salmonowicz, Hanna; Brown, Rachel; Turkowska, Joanna; Średniawa, Władysław; Pattabiraman, Sundararaghavan; Amen, Triana; Abraham, Ayelet-chen; Eichler, Noam; Lyakhovetsky, Roman; Kaganovich, Daniel

2014-06-03

Aging is associated with the accumulation of several types of damage: in particular, damage to the proteome. Recent work points to a conserved replicative rejuvenation mechanism that works by preventing the inheritance of damaged and misfolded proteins by specific cells during division. Asymmetric inheritance of misfolded and aggregated proteins has been shown in bacteria and yeast, but relatively little evidence exists for a similar mechanism in mammalian cells. Here, we demonstrate, using long-term 4D imaging, that the vimentin intermediate filament establishes mitotic polarity in mammalian cell lines and mediates the asymmetric partitioning of damaged proteins. We show that mammalian JUNQ inclusion bodies containing soluble misfolded proteins are inherited asymmetrically, similarly to JUNQ quality-control inclusions observed in yeast. Mammalian IPOD-like inclusion bodies, meanwhile, are not always inherited by the same cell as the JUNQ. Our study suggests that the mammalian cytoskeleton and intermediate filaments provide the physical scaffold for asymmetric inheritance of dynamic quality-control JUNQ inclusions. Mammalian IPOD inclusions containing amyloidogenic proteins are not partitioned as effectively during mitosis as their counterparts in yeast. These findings provide a valuable mechanistic basis for studying the process of asymmetric inheritance in mammalian cells, including cells potentially undergoing polar divisions, such as differentiating stem cells and cancer cells.

Multicatalyst system in asymmetric catalysis

CERN Document Server

Zhou, Jian

2014-01-01

This book introduces multi-catalyst systems by describing their mechanism and advantages in asymmetric catalysis.  Helps organic chemists perform more efficient catalysis with step-by-step methods  Overviews new concepts and progress for greener and economic catalytic reactions  Covers topics of interest in asymmetric catalysis including bifunctional catalysis, cooperative catalysis, multimetallic catalysis, and novel tandem reactions   Has applications for pharmaceuticals, agrochemicals, materials, and flavour and fragrance

A synthetic dataset for evaluating soft and hard fusion algorithms

Science.gov (United States)

Graham, Jacob L.; Hall, David L.; Rimland, Jeffrey

2011-06-01

There is an emerging demand for the development of data fusion techniques and algorithms that are capable of combining conventional "hard" sensor inputs such as video, radar, and multispectral sensor data with "soft" data including textual situation reports, open-source web information, and "hard/soft" data such as image or video data that includes human-generated annotations. New techniques that assist in sense-making over a wide range of vastly heterogeneous sources are critical to improving tactical situational awareness in counterinsurgency (COIN) and other asymmetric warfare situations. A major challenge in this area is the lack of realistic datasets available for test and evaluation of such algorithms. While "soft" message sets exist, they tend to be of limited use for data fusion applications due to the lack of critical message pedigree and other metadata. They also lack corresponding hard sensor data that presents reasonable "fusion opportunities" to evaluate the ability to make connections and inferences that span the soft and hard data sets. This paper outlines the design methodologies, content, and some potential use cases of a COIN-based synthetic soft and hard dataset created under a United States Multi-disciplinary University Research Initiative (MURI) program funded by the U.S. Army Research Office (ARO). The dataset includes realistic synthetic reports from a variety of sources, corresponding synthetic hard data, and an extensive supporting database that maintains "ground truth" through logical grouping of related data into "vignettes." The supporting database also maintains the pedigree of messages and other critical metadata.

Copper(II)-catalyzed enantioselective hydrosilylation of halo-substituted alkyl aryl and heteroaryl ketones: asymmetric synthesis of (R)-fluoxetine and (S)-duloxetine.

Science.gov (United States)

Zhou, Ji-Ning; Fang, Qiang; Hu, Yi-Hu; Yang, Li-Yao; Wu, Fei-Fei; Xie, Lin-Jie; Wu, Jing; Li, Shijun

2014-02-14

A set of reaction conditions has been established to facilitate the non-precious copper-catalyzed enantioselective hydrosilylation of a number of structurally diverse β-, γ- or ε-halo-substituted alkyl aryl ketones and α-, β- or γ-halo-substituted alkyl heteroaryl ketones under air to afford a broad spectrum of halo alcohols in high yields and good to excellent enantioselectivities (up to 99% ee). The developed procedure has been successfully applied to the asymmetric synthesis of antidepressant drugs (R)-fluoxetine and (S)-duloxetine, which highlighted its synthetic utility.

Enantioselective synthesis of chiral 3-aryl-1-indanones through rhodium-catalyzed asymmetric intramolecular 1,4-addition.

Science.gov (United States)

Yu, Yue-Na; Xu, Ming-Hua

2013-03-15

Enantioselective synthesis of potentially useful chiral 3-aryl-1-indanones was achieved through a rhodium-catalyzed asymmetric intramolecular 1,4-addition of pinacolborane chalcone derivatives using extraordinary simple MonoPhos as chiral ligand under relatively mild conditions. This novel protocol offers an easy access to a wide variety of enantioenriched 3-aryl-1-indanone derivatives in high yields (up to 95%) with excellent enantioselectivities (up to 95% ee).

Vortex Dynamics of Asymmetric Heave Plates

Science.gov (United States)

Rusch, Curtis; Maurer, Benjamin; Polagye, Brian

2017-11-01

Heave plates can be used to provide reaction forces for wave energy converters, which harness the power in ocean surface waves to produce electricity. Heave plate inertia includes both the static mass of the heave plate, as well as the ``added mass'' of surrounding water accelerated with the object. Heave plate geometries may be symmetric or asymmetric, with interest in asymmetric designs driven by the resulting hydrodynamic asymmetry. Limited flow visualization has been previously conducted on symmetric heave plates, but flow visualization of asymmetric designs is needed to understand the origin of observed hydrodynamic asymmetries and their dependence on the Keulegan-Carpenter number. For example, it is hypothesized that the time-varying added mass of asymmetric heave plates is caused by vortex shedding, which is related to oscillation amplitude. Here, using direct flow visualization, we explore the relationship between vortex dynamics and time-varying added mass and drag. These results suggest potential pathways for more advanced heave plate designs that can exploit vortex formation and shedding to achieve more favorable hydrodynamic properties for wave energy converters.

Renewable resource management under asymmetric information

DEFF Research Database (Denmark)

Jensen, Frank; Andersen, Peder; Nielsen, Max

2013-01-01

Asymmetric information between fishermen and the regulator is important within fisheries. The regulator may have less information about stock sizes, prices, costs, effort, productivity and catches than fishermen. With asymmetric information, a strong analytical tool is principal-agent analysis....... In this paper, we study asymmetric information about productivity within a principal-agent framework and a tax on fishing effort is considered. It is shown that a second best optimum can be achieved if the effort tax is designed such that low-productivity agents rent is exhausted, while high-productivity agents...... receive an information rent. The information rent is equivalent to the total incentive cost. The incentive costs arise as we want to reveal the agent's type....

Subcopula-based measure of asymmetric association for contingency tables.

Science.gov (United States)

Wei, Zheng; Kim, Daeyoung

2017-10-30

For the analysis of a two-way contingency table, a new asymmetric association measure is developed. The proposed method uses the subcopula-based regression between the discrete variables to measure the asymmetric predictive powers of the variables of interest. Unlike the existing measures of asymmetric association, the subcopula-based measure is insensitive to the number of categories in a variable, and thus, the magnitude of the proposed measure can be interpreted as the degree of asymmetric association in the contingency table. The theoretical properties of the proposed subcopula-based asymmetric association measure are investigated. We illustrate the performance and advantages of the proposed measure using simulation studies and real data examples. Copyright © 2017 John Wiley & Sons, Ltd.

Plant synthetic biology.

Science.gov (United States)

Liu, Wusheng; Stewart, C Neal

2015-05-01

Plant synthetic biology is an emerging field that combines engineering principles with plant biology toward the design and production of new devices. This emerging field should play an important role in future agriculture for traditional crop improvement, but also in enabling novel bioproduction in plants. In this review we discuss the design cycles of synthetic biology as well as key engineering principles, genetic parts, and computational tools that can be utilized in plant synthetic biology. Some pioneering examples are offered as a demonstration of how synthetic biology can be used to modify plants for specific purposes. These include synthetic sensors, synthetic metabolic pathways, and synthetic genomes. We also speculate about the future of synthetic biology of plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthetic nat- or ent-steroids in as few as five chemical steps from epichlorohydrin

Science.gov (United States)

Kim, Wan Shin; Du, Kang; Eastman, Alan; Hughes, Russell P.; Micalizio, Glenn C.

2018-01-01

Today, more than 100 Food and Drug Administration-approved steroidal agents are prescribed daily for indications including heart failure, inflammation, pain and cancer. While triumphs in organic chemistry have enabled the establishment and sustained growth of the steroid pharmaceutical industry, the production of highly functionalized synthetic steroids of varying substitution and stereochemistry remains challenging, despite the numerous reports of elegant strategies for their de novo synthesis. Here, we describe an advance in chemical synthesis that has established an enantiospecific means to access novel steroids with unprecedented facility and flexibility through the sequential use of two powerful ring-forming reactions: a modern metallacycle-mediated annulative cross-coupling and a new acid-catalysed vinylcyclopropane rearrangement cascade. In addition to accessing synthetic steroids of either enantiomeric series, these steroidal products have been selectively functionalized within each of the four carbocyclic rings, a synthetic ent-steroid has been prepared on a multigram scale, the enantiomer of a selective oestrogen has been synthesized, and a novel ent-steroid with growth inhibitory properties in three cancer cell lines has been discovered.

Modelling asymmetric growth in crowded plant communities

DEFF Research Database (Denmark)

Damgaard, Christian

2010-01-01

A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size......-asymmetric growth part, where growth is assumed to be proportional to a power function of the size of the individual, and a term that reduces the relative growth rate as a decreasing function of the individual plant size and the competitive interactions from other plants in the neighbourhood....

Asymmetric Frontal Brain Activity and Parental Rejection

NARCIS (Netherlands)

Huffmeijer, R.; Alink, L.R.A.; Tops, M.; Bakermans-Kranenburg, M.J.; van IJzendoorn, M.H.

2013-01-01

Asymmetric frontal brain activity has been widely implicated in reactions to emotional stimuli and is thought to reflect individual differences in approach-withdrawal motivation. Here, we investigate whether asymmetric frontal activity, as a measure of approach-withdrawal motivation, also predicts

Generation of human induced pluripotent stem cells using non-synthetic mRNA

Directory of Open Access Journals (Sweden)

L. Rohani

2016-05-01

Reprogramming with non-synthetic mRNA holds great promise for safe generation of iPSCs of human origin. Using the protocols described herein we hope to make this method more accessible to other groups as a fast, inexpensive, and non-viral reprogramming approach.

Asymmetric dominance and asymmetric mate choice oppose premating isolation after allopatric divergence.

Science.gov (United States)

Sefc, Kristina M; Hermann, Caroline M; Steinwender, Bernd; Brindl, Hanna; Zimmermann, Holger; Mattersdorfer, Karin; Postl, Lisbeth; Makasa, Lawrence; Sturmbauer, Christian; Koblmüller, Stephan

2015-04-01

Assortative mating promotes reproductive isolation and allows allopatric speciation processes to continue in secondary contact. As mating patterns are determined by mate preferences and intrasexual competition, we investigated male-male competition and behavioral isolation in simulated secondary contact among allopatric populations. Three allopatric color morphs of the cichlid fish Tropheus were tested against each other. Dyadic male-male contests revealed dominance of red males over bluish and yellow-blotch males. Reproductive isolation in the presence of male-male competition was assessed from genetic parentage in experimental ponds and was highly asymmetric among pairs of color morphs. Red females mated only with red males, whereas the other females performed variable degrees of heteromorphic mating. Discrepancies between mating patterns in ponds and female preferences in a competition-free, two-way choice paradigm suggested that the dominance of red males interfered with positive assortative mating of females of the subordinate morphs and provoked asymmetric hybridization. Between the nonred morphs, a significant excess of negative assortative mating by yellow-blotch females with bluish males did not coincide with asymmetric dominance among males. Hence, both negative assortative mating preferences and interference of male-male competition with positive assortative preferences forestall premating isolation, the latter especially in environments unsupportive of competition-driven spatial segregation.

Method development of damage detection in asymmetric buildings

Science.gov (United States)

Wang, Yi; Thambiratnam, David P.; Chan, Tommy H. T.; Nguyen, Andy

2018-01-01

Aesthetics and functionality requirements have caused most buildings to be asymmetric in recent times. Such buildings exhibit complex vibration characteristics under dynamic loads as there is coupling between the lateral and torsional components of vibration, and are referred to as torsionally coupled buildings. These buildings require three dimensional modelling and analysis. In spite of much recent research and some successful applications of vibration based damage detection methods to civil structures in recent years, the applications to asymmetric buildings has been a challenging task for structural engineers. There has been relatively little research on detecting and locating damage specific to torsionally coupled asymmetric buildings. This paper aims to compare the difference in vibration behaviour between symmetric and asymmetric buildings and then use the vibration characteristics for predicting damage in them. The need for developing a special method to detect damage in asymmetric buildings thus becomes evident. Towards this end, this paper modifies the traditional modal strain energy based damage index by decomposing the mode shapes into their lateral and vertical components and to form component specific damage indices. The improved approach is then developed by combining the modified strain energy based damage indices with the modal flexibility method which was modified to suit three dimensional structures to form a new damage indicator. The procedure is illustrated through numerical studies conducted on three dimensional five-story symmetric and asymmetric frame structures with the same layout, after validating the modelling techniques through experimental testing of a laboratory scale asymmetric building model. Vibration parameters obtained from finite element analysis of the intact and damaged building models are then applied into the proposed algorithms for detecting and locating the single and multiple damages in these buildings. The results

A proposed experimental search for chameleons using asymmetric parallel plates

International Nuclear Information System (INIS)

Burrage, Clare; Copeland, Edmund J.; Stevenson, James A.

2016-01-01

Light scalar fields coupled to matter are a common consequence of theories of dark energy and attempts to solve the cosmological constant problem. The chameleon screening mechanism is commonly invoked in order to suppress the fifth forces mediated by these scalars, sufficiently to avoid current experimental constraints, without fine tuning. The force is suppressed dynamically by allowing the mass of the scalar to vary with the local density. Recently it has been shown that near future cold atoms experiments using atom-interferometry have the ability to access a large proportion of the chameleon parameter space. In this work we demonstrate how experiments utilising asymmetric parallel plates can push deeper into the remaining parameter space available to the chameleon.

A proposed experimental search for chameleons using asymmetric parallel plates

Energy Technology Data Exchange (ETDEWEB)

Burrage, Clare; Copeland, Edmund J.; Stevenson, James A., E-mail: Clare.Burrage@nottingham.ac.uk, E-mail: ed.copeland@nottingham.ac.uk, E-mail: james.stevenson@nottingham.ac.uk [School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD (United Kingdom)

2016-08-01

Light scalar fields coupled to matter are a common consequence of theories of dark energy and attempts to solve the cosmological constant problem. The chameleon screening mechanism is commonly invoked in order to suppress the fifth forces mediated by these scalars, sufficiently to avoid current experimental constraints, without fine tuning. The force is suppressed dynamically by allowing the mass of the scalar to vary with the local density. Recently it has been shown that near future cold atoms experiments using atom-interferometry have the ability to access a large proportion of the chameleon parameter space. In this work we demonstrate how experiments utilising asymmetric parallel plates can push deeper into the remaining parameter space available to the chameleon.

Asymmetric Synthesis via Chiral Aziridines

DEFF Research Database (Denmark)

Tanner, David Ackland; Harden, Adrian; Wyatt, Paul

1996-01-01

A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines)]. In the b......A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines...

Optimal multicopy asymmetric Gaussian cloning of coherent states

International Nuclear Information System (INIS)

Fiurasek, Jaromir; Cerf, Nicolas J.

2007-01-01

We investigate the asymmetric Gaussian cloning of coherent states which produces M copies from N input replicas in such a way that the fidelity of each copy may be different. We show that the optimal asymmetric Gaussian cloning can be performed with a single phase-insensitive amplifier and an array of beam splitters. We obtain a simple analytical expression characterizing the set of optimal asymmetric Gaussian cloning machines and prove the optimality of these cloners using the formalism of Gaussian completely positive maps and semidefinite programming techniques. We also present an alternative implementation of the asymmetric cloning machine where the phase-insensitive amplifier is replaced with a beam splitter, heterodyne detector, and feedforward

Optimal multicopy asymmetric Gaussian cloning of coherent states

Science.gov (United States)

Fiurášek, Jaromír; Cerf, Nicolas J.

2007-05-01

We investigate the asymmetric Gaussian cloning of coherent states which produces M copies from N input replicas in such a way that the fidelity of each copy may be different. We show that the optimal asymmetric Gaussian cloning can be performed with a single phase-insensitive amplifier and an array of beam splitters. We obtain a simple analytical expression characterizing the set of optimal asymmetric Gaussian cloning machines and prove the optimality of these cloners using the formalism of Gaussian completely positive maps and semidefinite programming techniques. We also present an alternative implementation of the asymmetric cloning machine where the phase-insensitive amplifier is replaced with a beam splitter, heterodyne detector, and feedforward.

Survey of beta-particle interaction experiments with asymmetric matter

Science.gov (United States)

Van Horn, J. David; Wu, Fei

2018-05-01

Asymmetry is a basic property found at multiple scales in the universe. Asymmetric molecular interactions are fundamental to the operation of biological systems in both signaling and structural roles. Other aspects of asymmetry are observed and useful in many areas of science and engineering, and have been studied since the discovery of chirality in tartrate salts. The observation of parity violation in beta decay provided some impetus for later experiments using asymmetric particles. Here we survey historical work and experiments related to electron (e-) or positron (e+) polarimetry and their interactions with asymmetric materials in gas, liquid and solid forms. Asymmetric interactions may be classified as: 1) stereorecognition, 2) stereoselection and 3) stereoinduction. These three facets of physical stereochemistry are unique but interrelated; and examples from chemistry and materials science illustrate these aspects. Experimental positron and electron interactions with asymmetric materials may be classified in like manner. Thus, a qualitative assessment of helical and polarized positron experiments with different forms of asymmetric matter from the past 40 years is presented, as well as recent experiments with left-hand and right-hand single crystal quartz and organic compounds. The purpose of this classification and review is to evaluate the field for potential new experiments and directions for positron (or electron) studies with asymmetric materials.

Synthetic Cannabinoids

Directory of Open Access Journals (Sweden)

Aslihan Okan Ibiloglu

2017-09-01

Full Text Available Synthetic cannabinoids which is a subgroup of cannabinoids are commonly used for recreational drug use throughout the whole world. Although both marijuana and synthetic cannabinoids stimulate the same receptors, cannabinoid receptor 1 (CB1 and cannabinoid receptor 2 (CB2, studies have shown that synthetic cannabinoids are much more potent than marijuana. The longer use of synthetic cannabinoids can cause severe physical and psychological symptoms that might even result in death, similar to many known illicit drugs. Main treatment options mostly involve symptom management and supportive care. The aim of this article is to discuss clinical and pharmacological properties of the increasingly used synthetic cannabinoids. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2017; 9(3.000: 317-328

A spatial picture of the synthetic large-scale motion from dynamic roughness

Science.gov (United States)

Huynh, David; McKeon, Beverley

2017-11-01

Jacobi and McKeon (2011) set up a dynamic roughness apparatus to excite a synthetic, travelling wave-like disturbance in a wind tunnel, boundary layer study. In the present work, this dynamic roughness has been adapted for a flat-plate, turbulent boundary layer experiment in a water tunnel. A key advantage of operating in water as opposed to air is the longer flow timescales. This makes accessible higher non-dimensional actuation frequencies and correspondingly shorter synthetic length scales, and is thus more amenable to particle image velocimetry. As a result, this experiment provides a novel spatial picture of the synthetic mode, the coupled small scales, and their streamwise development. It is demonstrated that varying the roughness actuation frequency allows for significant tuning of the streamwise wavelength of the synthetic mode, with a range of 3 δ-13 δ being achieved. Employing a phase-locked decomposition, spatial snapshots are constructed of the synthetic large scale and used to analyze its streamwise behavior. Direct spatial filtering is used to separate the synthetic large scale and the related small scales, and the results are compared to those obtained by temporal filtering that invokes Taylor's hypothesis. The support of AFOSR (Grant # FA9550-16-1-0361) is gratefully acknowledged.

Asymmetric underlap optimization of sub-10nm finfets for realizing energy-efficient logic and robust memories

Science.gov (United States)

Akkala, Arun Goud

Leakage currents in CMOS transistors have risen dramatically with technology scaling leading to significant increase in standby power consumption. Among the various transistor candidates, the excellent short channel immunity of Silicon double gate FinFETs have made them the best contender for successful scaling to sub-10nm nodes. For sub-10nm FinFETs, new quantum mechanical leakage mechanisms such as direct source to drain tunneling (DSDT) of charge carriers through channel potential energy barrier arising due to proximity of source/drain regions coupled with the high transport direction electric field is expected to dominate overall leakage. To counter the effects of DSDT and worsening short channel effects and to maintain Ion/ Ioff, performance and power consumption at reasonable values, device optimization techniques are necessary for deeply scaled transistors. In this work, source/drain underlapping of FinFETs has been explored using quantum mechanical device simulations as a potentially promising method to lower DSDT while maintaining the Ion/ Ioff ratio at acceptable levels. By adopting a device/circuit/system level co-design approach, it is shown that asymmetric underlapping, where the drain side underlap is longer than the source side underlap, results in optimal energy efficiency for logic circuits in near-threshold as well as standard, super-threshold operating regimes. In addition, read/write conflict in 6T SRAMs and the degradation in cell noise margins due to the low supply voltage can be mitigated by using optimized asymmetric underlapped n-FinFETs for the access transistor, thereby leading to robust cache memories. When gate-workfunction tuning is possible, using asymmetric underlapped n-FinFETs for both access and pull-down devices in an SRAM bit cell can lead to high-speed and low-leakage caches. Further, it is shown that threshold voltage degradation in the presence of Hot Carrier Injection (HCI) is less severe in asymmetric underlap n-FinFETs. A

Organocatalytic asymmetric selenofunctionalization of tryptamine for the synthesis of hexahydropyrrolo[2,3-b]indole derivatives

Directory of Open Access Journals (Sweden)

Qiang Wei

2013-08-01

Full Text Available A chiral phosphoric acid-catalyzed selenofunctionalization of tryptamine derivatives provides access to 3a-(phenylselenyl-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole derivatives in high yields and with synthetically useful levels of enantioselectivity (up to 89% ee.

Scaling up DNA data storage and random access retrieval

OpenAIRE

Gopalan, Parikshit; Ceze, Luis; Nguyen, Bichlien; Takahashi, Christopher; Newman, Sharon; Parker, Hsing-Yeh; Rashtchian, Cyrus; Seelig, Georg; Stewart, Kendall; Gupta, Gagan; Carlson, Robert; Mulligan, John; Carmean, Douglas; Yekhanin, Sergey; Makarychev, Konstantin

2017-01-01

Current storage technologies can no longer keep pace with exponentially growing amounts of data. Synthetic DNA offers an attractive alternative due to its potential information density of ~ 1018B/mm3, 107 times denser than magnetic tape, and potential durability of thousands of years. Recent advances in DNA data storage have highlighted technical challenges, in particular, coding and random access, but have stored only modest amounts of data in synthetic DNA. This paper demonstrates an end-to...

Seamless Synthetic Aperture Radar Archive for Interferometry Analysis

Science.gov (United States)

Baker, S.; Baru, C.; Bryson, G.; Buechler, B.; Crosby, C.; Fielding, E.; Meertens, C.; Nicoll, J.; Youn, C.

2014-11-01

The NASA Advancing Collaborative Connections for Earth System Science (ACCESS) seamless synthetic aperture radar (SAR) archive (SSARA) project is a collaboration between UNAVCO, the Alaska Satellite Facility (ASF), the Jet Propulsion Laboratory (JPL), and OpenTopography at the San Diego Supercomputer Center (SDSC) to design and implement a seamless distributed access system for SAR data and derived interferometric SAR (InSAR) data products. A unified application programming interface (API) has been created to search the SAR archives at ASF and UNAVCO, 30 and 90-m SRTM DEM data available through OpenTopography, and tropospheric data from the NASA OSCAR project at JPL. The federated query service provides users a single access point to search for SAR granules, InSAR pairs, and corresponding DEM and tropospheric data products from the four archives, as well as the ability to search and download pre-processed InSAR products from ASF and UNAVCO.

VisBOL: Web-Based Tools for Synthetic Biology Design Visualization.

Science.gov (United States)

McLaughlin, James Alastair; Pocock, Matthew; Mısırlı, Göksel; Madsen, Curtis; Wipat, Anil

2016-08-19

VisBOL is a Web-based application that allows the rendering of genetic circuit designs, enabling synthetic biologists to visually convey designs in SBOL visual format. VisBOL designs can be exported to formats including PNG and SVG images to be embedded in Web pages, presentations and publications. The VisBOL tool enables the automated generation of visualizations from designs specified using the Synthetic Biology Open Language (SBOL) version 2.0, as well as a range of well-known bioinformatics formats including GenBank and Pigeoncad notation. VisBOL is provided both as a user accessible Web site and as an open-source (BSD) JavaScript library that can be used to embed diagrams within other content and software.

Time-Dependent-Asymmetric-Linear-Parsimonious Ancestral State Reconstruction.

Science.gov (United States)

Didier, Gilles

2017-10-01

The time-dependent-asymmetric-linear parsimony is an ancestral state reconstruction method which extends the standard linear parsimony (a.k.a. Wagner parsimony) approach by taking into account both branch lengths and asymmetric evolutionary costs for reconstructing quantitative characters (asymmetric costs amount to assuming an evolutionary trend toward the direction with the lowest cost). A formal study of the influence of the asymmetry parameter shows that the time-dependent-asymmetric-linear parsimony infers states which are all taken among the known states, except for some degenerate cases corresponding to special values of the asymmetry parameter. This remarkable property holds in particular for the Wagner parsimony. This study leads to a polynomial algorithm which determines, and provides a compact representation of, the parametric reconstruction of a phylogenetic tree, that is for all the unknown nodes, the set of all the possible reconstructed states associated with the asymmetry parameters leading to them. The time-dependent-asymmetric-linear parsimony is finally illustrated with the parametric reconstruction of the body size of cetaceans.

Regio- and enantioselective synthesis of N-substituted pyrazoles by rhodium-catalyzed asymmetric addition to allenes.

Science.gov (United States)

Haydl, Alexander M; Xu, Kun; Breit, Bernhard

2015-06-08

The rhodium-catalyzed asymmetric N-selective coupling of pyrazole derivatives with terminal allenes gives access to enantioenriched secondary and tertiary allylic pyrazoles, which can be employed for the synthesis of medicinally important targets. The reaction tolerates a large variety of functional groups and labelling experiments gave insights into the reaction mechanism. This new methodology was further applied in a highly efficient synthesis of JAK 1/2 inhibitor (R)-ruxolitinib. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

Directory of Open Access Journals (Sweden)

Pankaj Chauhan

2012-12-01

Full Text Available Ball-milling and pestle and mortar grinding have emerged as powerful methods for the development of environmentally benign chemical transformations. Recently, the use of these mechanochemical techniques in asymmetric organocatalysis has increased. This review highlights the progress in asymmetric organocatalytic reactions assisted by mechanochemical techniques.

[From synthetic biology to synthetic humankind].

Science.gov (United States)

Nouvel, Pascal

2015-01-01

In this paper, we propose an historical survey of the expression "synthetic biology" in order to identify its main philosophical components. The result of the analysis is then used to investigate the meaning of the notion of "synthetic man". It is shown that both notions share a common philosophical background that can be summed up by the short but meaningful assertion: "biology is technology". The analysis allows us to distinguish two notions that are often confused in transhumanist literature: the notion of synthetic man and the notion of renewed man. The consequences of this crucial distinction are discussed. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Asymmetric strand segregation: epigenetic costs of genetic fidelity?

Directory of Open Access Journals (Sweden)

Diane P Genereux

2009-06-01

Full Text Available Asymmetric strand segregation has been proposed as a mechanism to minimize effective mutation rates in epithelial tissues. Under asymmetric strand segregation, the double-stranded molecule that contains the oldest DNA strand is preferentially targeted to the somatic stem cell after each round of DNA replication. This oldest DNA strand is expected to have fewer errors than younger strands because some of the errors that arise on daughter strands during their synthesis fail to be repaired. Empirical findings suggest the possibility of asymmetric strand segregation in a subset of mammalian cell lineages, indicating that it may indeed function to increase genetic fidelity. However, the implications of asymmetric strand segregation for the fidelity of epigenetic information remain unexplored. Here, I explore the impact of strand-segregation dynamics on epigenetic fidelity using a mathematical-modelling approach that draws on the known molecular mechanisms of DNA methylation and existing rate estimates from empirical methylation data. I find that, for a wide range of starting methylation densities, asymmetric -- but not symmetric -- strand segregation leads to systematic increases in methylation levels if parent strands are subject to de novo methylation events. I found that epigenetic fidelity can be compromised when enhanced genetic fidelity is achieved through asymmetric strand segregation. Strand segregation dynamics could thus explain the increased DNA methylation densities that are observed in structured cellular populations during aging and in disease.

Ideal 3D asymmetric concentrator

Energy Technology Data Exchange (ETDEWEB)

Garcia-Botella, Angel [Departamento Fisica Aplicada a los Recursos Naturales, Universidad Politecnica de Madrid, E.T.S.I. de Montes, Ciudad Universitaria s/n, 28040 Madrid (Spain); Fernandez-Balbuena, Antonio Alvarez; Vazquez, Daniel; Bernabeu, Eusebio [Departamento de Optica, Universidad Complutense de Madrid, Fac. CC. Fisicas, Ciudad Universitaria s/n, 28040 Madrid (Spain)

2009-01-15

Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used for producing reflective and refractive optical devices, including reverse engineering techniques. In this paper we apply photometric field theory and elliptic ray bundles method to study 3D asymmetric - without rotational or translational symmetry - concentrators, which can be useful components for nontracking solar applications. We study the one-sheet hyperbolic concentrator and we demonstrate its behaviour as ideal 3D asymmetric concentrator. (author)

Computational synthetic geometry

CERN Document Server

Bokowski, Jürgen

1989-01-01

Computational synthetic geometry deals with methods for realizing abstract geometric objects in concrete vector spaces. This research monograph considers a large class of problems from convexity and discrete geometry including constructing convex polytopes from simplicial complexes, vector geometries from incidence structures and hyperplane arrangements from oriented matroids. It turns out that algorithms for these constructions exist if and only if arbitrary polynomial equations are decidable with respect to the underlying field. Besides such complexity theorems a variety of symbolic algorithms are discussed, and the methods are applied to obtain new mathematical results on convex polytopes, projective configurations and the combinatorics of Grassmann varieties. Finally algebraic varieties characterizing matroids and oriented matroids are introduced providing a new basis for applying computer algebra methods in this field. The necessary background knowledge is reviewed briefly. The text is accessible to stud...

Synthetic biology and biosecurity: challenging the "myths".

OpenAIRE

Jefferson, C; Lentzos, F; Marris, C

2014-01-01

15.10.14 KB. Ok to add published version to spiral, OA paper under cc by Synthetic biology, a field that aims to make biology easier to engineer, is routinely described as leading to an increase in the dual-use threat, i.e., the potential for the same scientific research to be used for peaceful purposes or misused for warfare or terrorism. Fears have been expressed that the de-skilling of biology, combined with online access to the genomic DNA sequences of pathogenic organisms an...

Asymmetric hindwing foldings in rove beetles.

Science.gov (United States)

Saito, Kazuya; Yamamoto, Shuhei; Maruyama, Munetoshi; Okabe, Yoji

2014-11-18

Foldable wings of insects are the ultimate deployable structures and have attracted the interest of aerospace engineering scientists as well as entomologists. Rove beetles are known to fold their wings in the most sophisticated ways that have right-left asymmetric patterns. However, the specific folding process and the reason for this asymmetry remain unclear. This study reveals how these asymmetric patterns emerge as a result of the folding process of rove beetles. A high-speed camera was used to reveal the details of the wing-folding movement. The results show that these characteristic asymmetrical patterns emerge as a result of simultaneous folding of overlapped wings. The revealed folding mechanisms can achieve not only highly compact wing storage but also immediate deployment. In addition, the right and left crease patterns are interchangeable, and thus each wing internalizes two crease patterns and can be folded in two different ways. This two-way folding gives freedom of choice for the folding direction to a rove beetle. The use of asymmetric patterns and the capability of two-way folding are unique features not found in artificial structures. These features have great potential to extend the design possibilities for all deployable structures, from space structures to articles of daily use.

Asymmetric catalysis in Brazil: development and potential for advancement of Brazilian chemical industry; Catalise assimetrica no Brasil: desenvolvimento e potencialidades para o avanco da industria quimica brasileira

Energy Technology Data Exchange (ETDEWEB)

Braga, Antonio Luiz, E-mail: braga.antonio@ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Departamento de Quimica; Luedtke, Diogo Seibert; Schneider, Paulo Henrique [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Instituto de Quimica; Andrade, Leandro Helgueira [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica; Paixao, Marcio Weber [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

2013-07-01

The preparation of enantiomerically pure or enriched substances is of fundamental importance to pharmaceutical, food, agrochemical, and cosmetics industries and involves a growing market of hundreds of billions of dollars. However, most chemical processes used for their production are not environmentally friendly because in most cases, stoichiometric amounts of chiral inductors are used and substantial waste is produced. In this context, asymmetric catalysis has emerged as an efficient tool for the synthesis of enantiomerically enriched compounds using chiral catalysts. More specifically, considering the current scenario in the Brazilian chemical industry, especially that of pharmaceuticals, the immediate prospect for the use of synthetic routes developed in Brazil in an enantioselective fashion or even the discovery of new drugs is practically null. Currently, the industrial production of drugs in Brazil is primarily focused on the production of generic drugs and is basically supported by imports of intermediates from China and India. In order to change this panorama and move forward toward the gradual incorporation of genuinely Brazilian synthetic routes, strong incentive policies, especially those related to continuous funding, will be needed. These incentives could be a breakthrough once we establish several research groups working in the area of organic synthesis and on the development and application of chiral organocatalysts and ligands in asymmetric catalysis, thus contributing to boost the development of the Brazilian chemical industry. Considering these circumstances, Brazil can benefit from this opportunity because we have a wide biodiversity and a large pool of natural resources that can be used as starting materials for the production of new chiral catalysts and are creating competence in asymmetric catalysis and related areas. This may decisively contribute to the growth of chemistry in our country. (author)

Email authentication using symmetric and asymmetric key algorithm encryption

Science.gov (United States)

Halim, Mohamad Azhar Abdul; Wen, Chuah Chai; Rahmi, Isredza; Abdullah, Nurul Azma; Rahman, Nurul Hidayah Ab.

2017-10-01

Protection of sensitive or classified data from unauthorized access, hackers and other personals is virtue. Storage of data is done in devices such as USB, external hard disk, laptops, I-Pad or at cloud. Cloud computing presents with both ups and downs. However, storing information elsewhere increases risk of being attacked by hackers. Besides, the risk of losing the device or being stolen is increased in case of storage in portable devices. There are array of mediums of communications and even emails used to send data or information but these technologies come along with severe weaknesses such as absence of confidentiality where the message sent can be altered and sent to the recipient. No proofs are shown to the recipient that the message received is altered. The recipient would not find out unless he or she checks with the sender. Without encrypted of data or message, sniffing tools and software can be used to hack and read the information since it is in plaintext. Therefore, an electronic mail authentication is proposed, namely Hybrid Encryption System (HES). The security of HES is protected using asymmetric and symmetric key algorithms. The asymmetric algorithm is RSA and symmetric algorithm is Advance Encryption Standard. With the combination for both algorithms in the HES may provide the confidentiality and authenticity to the electronic documents send from the sender to the recipient. In a nutshell, the HES will help users to protect their valuable documentation and data from illegal third party user.

The Wing Beat of the Butterfly. The Causality of Asymmetric Cultural Encounters and Escalation in Babel (2006 and Valley of Wolves – Iraq/ Kurtlar Vadisi – Irak (2006

Directory of Open Access Journals (Sweden)

Veronika Bernard

2011-10-01

Full Text Available The term ‘asymmetric conflict’ describes a war-like situation in which the opponents involved do not have equal access to decisive logistic resources. The author of this article states that cultural en­coun­ters can also be of asymmetric quality: in situations of provoked or accidental (intercultural mis­understandings, in hierarchical situations and in cases of emergency. She further states that the mo­vies Babel (2006 and Valley of Wolves – Iraq (2006 can be seen as cinematic adaptations of such cases putting the focus on the causality of asymmetric cultural encounters and escalation. The ar­tic­le deals with the major cinematic tools applied in visualizing this causality in the two films.

Asymmetric Aldol Additions: A Guided-Inquiry Laboratory Activity on Catalysis

Science.gov (United States)

King, Jorge H. Torres; Wang, Hong; Yezierski, Ellen J.

2018-01-01

Despite the importance of asymmetric catalysis in both the pharmaceutical and commodity chemicals industries, asymmetric catalysis is under-represented in undergraduate chemistry laboratory curricula. A novel guided-inquiry experiment based on the asymmetric aldol addition was developed. Students conduct lab work to compare the effectiveness of…

Parallel coupling of symmetric and asymmetric exclusion processes

International Nuclear Information System (INIS)

Tsekouras, K; Kolomeisky, A B

2008-01-01

A system consisting of two parallel coupled channels where particles in one of them follow the rules of totally asymmetric exclusion processes (TASEP) and in another one move as in symmetric simple exclusion processes (SSEP) is investigated theoretically. Particles interact with each other via hard-core exclusion potential, and in the asymmetric channel they can only hop in one direction, while on the symmetric lattice particles jump in both directions with equal probabilities. Inter-channel transitions are also allowed at every site of both lattices. Stationary state properties of the system are solved exactly in the limit of strong couplings between the channels. It is shown that strong symmetric couplings between totally asymmetric and symmetric channels lead to an effective partially asymmetric simple exclusion process (PASEP) and properties of both channels become almost identical. However, strong asymmetric couplings between symmetric and asymmetric channels yield an effective TASEP with nonzero particle flux in the asymmetric channel and zero flux on the symmetric lattice. For intermediate strength of couplings between the lattices a vertical-cluster mean-field method is developed. This approximate approach treats exactly particle dynamics during the vertical transitions between the channels and it neglects the correlations along the channels. Our calculations show that in all cases there are three stationary phases defined by particle dynamics at entrances, at exits or in the bulk of the system, while phase boundaries depend on the strength and symmetry of couplings between the channels. Extensive Monte Carlo computer simulations strongly support our theoretical predictions. Theoretical calculations and computer simulations predict that inter-channel couplings have a strong effect on stationary properties. It is also argued that our results might be relevant for understanding multi-particle dynamics of motor proteins

Multipartite asymmetric quantum cloning

International Nuclear Information System (INIS)

Iblisdir, S.; Gisin, N.; Acin, A.; Cerf, N.J.; Filip, R.; Fiurasek, J.

2005-01-01

We investigate the optimal distribution of quantum information over multipartite systems in asymmetric settings. We introduce cloning transformations that take N identical replicas of a pure state in any dimension as input and yield a collection of clones with nonidentical fidelities. As an example, if the clones are partitioned into a set of M A clones with fidelity F A and another set of M B clones with fidelity F B , the trade-off between these fidelities is analyzed, and particular cases of optimal N→M A +M B cloning machines are exhibited. We also present an optimal 1→1+1+1 cloning machine, which is an example of a tripartite fully asymmetric cloner. Finally, it is shown how these cloning machines can be optically realized

Seasonally asymmetric enhancement of northern vegetation productivity

Science.gov (United States)

Park, T.; Myneni, R.

2017-12-01

Multiple evidences of widespread greening and increasing terrestrial carbon uptake have been documented. In particular, enhanced gross productivity of northern vegetation has been a critical role leading to observed carbon uptake trend. However, seasonal photosynthetic activity and its contribution to observed annual carbon uptake trend and interannual variability are not well understood. Here, we introduce a multiple-source of datasets including ground, atmospheric and satellite observations, and multiple process-based global vegetation models to understand how seasonal variation of land surface vegetation controls a large-scale carbon exchange. Our analysis clearly shows a seasonally asymmetric enhancement of northern vegetation productivity in growing season during last decades. Particularly, increasing gross productivity in late spring and early summer is obvious and dominant driver explaining observed trend and variability. We observe more asymmetric productivity enhancement in warmer region and this spatially varying asymmetricity in northern vegetation are likely explained by canopy development rate, thermal and light availability. These results imply that continued warming may facilitate amplifying asymmetric vegetation activity and cause these trends to become more pervasive, in turn warming induced regime shift in northern land.

Asymmetric Price Responses of Gasoline Stations. Evidence for Heterogeneity of Retailers

Energy Technology Data Exchange (ETDEWEB)

Faber, R.P. [Erasmus University Rotterdam, Rotterdam (Netherlands)

2009-11-15

This paper studies asymmetric price responses of individual firms, via daily retail prices of almost all gasoline stations in the Netherlands and suggested prices of the five largest oil companies over more than two years. I find that 38% of the stations respond asymmetrically to changes in the spot market price. Hence, asymmetric pricing is not a feature of the market as a whole, but of individual firms. For asymmetrically pricing stations, the asymmetry is substantial directly after a change but disappears after one or two days. I study station-specific characteristics and conclude that asymmetric pricing seems to be a phenomenon that is randomly distributed across stations. I also find that none of the five largest oil companies adjust their suggested prices asymmetrically.

Asymmetric Price Responses of Gasoline Stations. Evidence for Heterogeneity of Retailers

International Nuclear Information System (INIS)

Faber, R.P.

2009-11-01

This paper studies asymmetric price responses of individual firms, via daily retail prices of almost all gasoline stations in the Netherlands and suggested prices of the five largest oil companies over more than two years. I find that 38% of the stations respond asymmetrically to changes in the spot market price. Hence, asymmetric pricing is not a feature of the market as a whole, but of individual firms. For asymmetrically pricing stations, the asymmetry is substantial directly after a change but disappears after one or two days. I study station-specific characteristics and conclude that asymmetric pricing seems to be a phenomenon that is randomly distributed across stations. I also find that none of the five largest oil companies adjust their suggested prices asymmetrically.

Observation of asymmetric electromagnetic field profiles in chiral metamaterials

Science.gov (United States)

Hisamoto, Nobuyuki; Ueda, Tetsuya; Sawada, Kei; Tomita, Satoshi

2018-02-01

We experimentally observe asymmetric electromagnetic field profiles along two-dimensional chiral metamaterials. The asymmetric field profiles depending on the chirality and the operation frequency have been reproduced well by the numerical simulation. Around a chiral meta-atom, distribution of a Poynting vector is found to be shifted asymmetrically. These results are explained in terms of an analogy with the side-jump mechanism in the electronic anomalous Hall systems.

Synthetic biology approaches to fluorinated polyketides.

Science.gov (United States)

Thuronyi, Benjamin W; Chang, Michelle C Y

2015-03-17

The catalytic diversity of living systems offers a broad range of opportunities for developing new methods to produce small molecule targets such as fuels, materials, and pharmaceuticals. In addition to providing cost-effective and renewable methods for large-scale commercial processes, the exploration of the unusual chemical phenotypes found in living organisms can also enable the expansion of chemical space for discovery of novel function by combining orthogonal attributes from both synthetic and biological chemistry. In this context, we have focused on the development of new fluorine chemistry using synthetic biology approaches. While fluorine has become an important feature in compounds of synthetic origin, the scope of biological fluorine chemistry in living systems is limited, with fewer than 20 organofluorine natural products identified to date. In order to expand the diversity of biosynthetically accessible organofluorines, we have begun to develop methods for the site-selective introduction of fluorine into complex natural products by engineering biosynthetic machinery to incorporate fluorinated building blocks. To gain insight into how both enzyme active sites and metabolic pathways can be evolved to manage and select for fluorinated compounds, we have studied one of the only characterized natural hosts for organofluorine biosynthesis, the soil microbe Streptomyces cattleya. This information provides a template for designing engineered organofluorine enzymes, pathways, and hosts and has allowed us to initiate construction of enzymatic and cellular pathways for the production of fluorinated polyketides.

Volatile and Nonvolatile Characteristics of Asymmetric Dual-Gate Thyristor RAM with Vertical Structure.

Science.gov (United States)

Kim, Hyun-Min; Kwon, Dae Woong; Kim, Sihyun; Lee, Kitae; Lee, Junil; Park, Euyhwan; Lee, Ryoongbin; Kim, Hyungjin; Kim, Sangwan; Park, Byung-Gook

2018-09-01

In this paper, the volatile and nonvolatile characteristics of asymmetric dual-gate thyristor random access memory (TRAM) are investigated using the technology of a computer-aided design (TCAD) simulation. Owing to the use of two independent gates having different gate dielectric layers, volatile and nonvolatile memory functions can be realized in a single device. The first gate with a silicon oxide layer controls the one-transistor dynamic random access memory (1T-DRAM) characteristics of the device. From the simulation results, a rapid write speed (107) can be achieved. The second gate, whose dielectric material is composed of oxide/nitride/oxide (O/N/O) layers, is used to implement the nonvolatile property by trapping charges in the nitride layer. In addition, this offers an advantage when processing the 3D-stack memory application, as the device has a vertical channel structure with polycrystalline silicon.

Norbadione A: synthetic approach and cesium complexation studies

International Nuclear Information System (INIS)

Desage - El Murr, M.

2003-10-01

This work was dedicated to the study of the synthesis and complexation studies of norbadione A: a pigment originating from a mushroom. A synthetic approach, based on a double Suzuki-Miyaura coupling, was developed. This strategy was applied with high yields to the synthesis of various norbadione A analogues, as well as to the synthesis of simple pulvinic acids. Access to functionalized precursors of the molecule was also studied and the final coupling remains to be done. Besides, a speciation study based on electro-spray ionization mass spectrometry was conducted with norbadione A and one of the analogues. This study allowed the assessment of the cesium complexation abilities of each molecule. Structural data was also obtained and complexation constants were calculated. Finally, norbadione A and various synthetic products have been tested via high-throughput screening methods and strong antioxidant properties were observed. Other biological results are also reported. (author)

Rhodium-catalyzed Asymmetric Hydrogenation of α-Dehydroamino Ketones: A General Approach to Chiral α-amino Ketones.

Science.gov (United States)

Gao, Wenchao; Wang, Qingli; Xie, Yun; Lv, Hui; Zhang, Xumu

2016-01-01

Rhodium/DuanPhos-catalyzed asymmetric hydrogenation of aliphatic α-dehydroamino ketones has been achieved and afforded chiral α-amino ketones in high yields and excellent enantioselectives (up to 99 % ee), which could be reduced further to chiral β-amino alcohols by LiAlH(tBuO)3 with good yields. This protocol provides a readily accessible route for the synthesis of chiral α-amino ketones and chiral β-amino alcohols. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new convenient asymmetric approach to herbarumin Ⅲ

Institute of Scientific and Technical Information of China (English)

Xue Song Chen; Shi Jun Da; Li Hong Yang; Bo Yan Xu; Zhi Xiang Xie; Ying Li

2007-01-01

The asymmetric total synthesis of herbarumin Ⅲ 3, a naturally occurred phytotoxin, along with 8-epi-herbarumin Ⅲ 22, was succeeded in 12 steps from n-butyraldehyde based on Brown's asymmetric allylation, taking modified Julia olefination and Yamaguchi's macro-lactonization as key steps.

Fourier synthesis of asymmetrical optical potentials for atoms

International Nuclear Information System (INIS)

Ritt, G.

2007-01-01

In this work a dissipationless asymmetrical optical potential for cold atoms was produced. In a first step a new type of optical lattice was generated, whose spatial periodicity only corresponds to a quarter of the wavelength of the light used for the generation. This corresponds to the half of the periodicity of a conventional optical lattice, which is formed by the light of the same wavelength. The generation of this new type of optical lattice was reached by the use of two degenerated raman transitions. Virtual processes occur, in which four photons are involved. In conventional optical lattices however virtual two-photon processes occur. By spatially superimposing this optical lattice with a conventional optical lattice an asymmetrical optical potential could be formed. By diffraction of a Bose Einstein condensate of rubidium atoms at the transient activated asymmetrical potential the asymmetrical structure was proven. (orig.)

Pentavalent Uranium Chemistry - Synthetic Pursuit Of A Rare Oxidation State

Energy Technology Data Exchange (ETDEWEB)

Graves, Christopher R [Los Alamos National Laboratory; Kiplinger, Jaqueline L [Los Alamos National Laboratory

2009-01-01

This feature article presents a comprehensive overview of pentavalent uranium systems in non-aqueous solution with a focus on the various synthetic avenues employed to access this unusual and very important oxidation state. Selected characterization data and theoretical aspects are also included. The purpose is to provide a perspective on this rapidly evolving field and identify new possibilities for future developments in pentavalent uranium chemistry.

Engineered Asymmetric Composite Membranes with Rectifying Properties.

Science.gov (United States)

Wen, Liping; Xiao, Kai; Sainath, Annadanam V Sesha; Komura, Motonori; Kong, Xiang-Yu; Xie, Ganhua; Zhang, Zhen; Tian, Ye; Iyoda, Tomokazu; Jiang, Lei

2016-01-27

Asymmetric composite membranes with rectifying properties are developed by grafting pH-stimulus-responsive materials onto the top layer of the composite structure, which is prepared by two novel block copolymers using a phase-separation technique. This engineered asymmetric composite membrane shows potential applications in sensors, filtration, and nanofluidic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Variable angle asymmetric cut monochromator

International Nuclear Information System (INIS)

Smither, R.K.; Fernandez, P.B.

1993-09-01

A variable incident angle, asymmetric cut, double crystal monochromator was tested for use on beamlines at the Advanced Photon Source (APS). For both undulator and wiggler beams the monochromator can expand area of footprint of beam on surface of the crystals to 50 times the area of incident beam; this will reduce the slope errors by a factor of 2500. The asymmetric cut allows one to increase the acceptance angle for incident radiation and obtain a better match to the opening angle of the incident beam. This can increase intensity of the diffracted beam by a factor of 2 to 5 and can make the beam more monochromatic, as well. The monochromator consists of two matched, asymmetric cut (18 degrees), silicon crystals mounted so that they can be rotated about three independent axes. Rotation around the first axis controls the Bragg angle. The second rotation axis is perpendicular to the diffraction planes and controls the increase of the area of the footprint of the beam on the crystal surface. Rotation around the third axis controls the angle between the surface of the crystal and the wider, horizontal axis for the beam and can make the footprint a rectangle with a minimum. length for this area. The asymmetric cut is 18 degrees for the matched pair of crystals, which allows one to expand the footprint area by a factor of 50 for Bragg angles up to 19.15 degrees (6 keV for Si[111] planes). This monochromator, with proper cooling, will be useful for analyzing the high intensity x-ray beams produced by both undulators and wigglers at the APS

Jet-torus connection in radio galaxies. Relativistic hydrodynamics and synthetic emission

Science.gov (United States)

Fromm, C. M.; Perucho, M.; Porth, O.; Younsi, Z.; Ros, E.; Mizuno, Y.; Zensus, J. A.; Rezzolla, L.

2018-01-01

Context. High resolution very long baseline interferometry observations of active galactic nuclei have revealed asymmetric structures in the jets of radio galaxies. These asymmetric structures may be due to internal asymmetries in the jets or they may be induced by the different conditions in the surrounding ambient medium, including the obscuring torus, or a combination of the two. Aims: In this paper we investigate the influence of the ambient medium, including the obscuring torus, on the observed properties of jets from radio galaxies. Methods: We performed special-relativistic hydrodynamic (SRHD) simulations of over-pressured and pressure-matched jets using the special-relativistic hydrodynamics code Ratpenat, which is based on a second-order accurate finite-volume method and an approximate Riemann solver. Using a newly developed radiative transfer code to compute the electromagnetic radiation, we modelled several jets embedded in various ambient medium and torus configurations and subsequently computed the non-thermal emission produced by the jet and thermal absorption from the torus. To better compare the emission simulations with observations we produced synthetic radio maps, taking into account the properties of the observatory. Results: The detailed analysis of our simulations shows that the observed properties such as core shift could be used to distinguish between over-pressured and pressure matched jets. In addition to the properties of the jets, insights into the extent and density of the obscuring torus can be obtained from analyses of the single-dish spectrum and spectral index maps.

Decrease in back strength in asymmetric trunk postures

NARCIS (Netherlands)

Vink, P.; Daanen, H. A M; Meijst, W. J.; Ligteringen, J.

1992-01-01

The extension force against resistance was recorded in 23 postures for 12 subjects to find explanations for the decrease in back strength in asymmetric postures. A reduction in muscle force in asymmetric postures was found up to 40%, but was strongly dependent on the plane in which asymmetry

Subglottic cysts and asymmetrical subglottic narrowing on neck radiograph

International Nuclear Information System (INIS)

Holinger, L.D.; Torium, D.M.; Anandappa, E.C.

1988-01-01

The congenital subglottic hemangioma typically appears as an asymmetric subglottic narrowing or mass on frontal neck radiograph. Therefore, soft tissue neck radiography has been advocated as a definitive non-operative approach for diagnosing these lesions. However, we have noted similar asymmetric subglottic narrowing in patients with acquired subglottic cysts. These retention cysts occur following long-term intubation in the neonate. The mechanism probably involves subglottic fibrosis which obstructs glands with subsequent cyst formation. Acquired subglottic cysts typically appear as an asymmetric narrowing on frontal or lateral soft tissue neck radiographs. These lesions may produce airway compromise but are effectively treated by forceps or laser removal. Acquired subglottic cysts must be included in the differential diagnosis of asymmetric subglottic narrowing. The definitive diagnosis is made by direct laryngoscopy, not soft tissue neck radiograph. (orig.)

Lower Bounds in the Asymmetric External Memory Model

DEFF Research Database (Denmark)

Jacob, Riko; Sitchinava, Nodari

2017-01-01

Motivated by the asymmetric read and write costs of emerging non-volatile memory technologies, we study lower bounds for the problems of sorting, permuting and multiplying a sparse matrix by a dense vector in the asymmetric external memory model (AEM). Given an AEM with internal (symmetric) memory...... of size M, transfers between symmetric and asymmetric memory in blocks of size B and the ratio ω between write and read costs, we show Ω(min (N, ωN/B logω M/B N/B) lower bound for the cost of permuting N input elements. This lower bound also applies to the problem of sorting N elements. This proves...

Designing synthetic biology.

Science.gov (United States)

Agapakis, Christina M

2014-03-21

Synthetic biology is frequently defined as the application of engineering design principles to biology. Such principles are intended to streamline the practice of biological engineering, to shorten the time required to design, build, and test synthetic gene networks. This streamlining of iterative design cycles can facilitate the future construction of biological systems for a range of applications in the production of fuels, foods, materials, and medicines. The promise of these potential applications as well as the emphasis on design has prompted critical reflection on synthetic biology from design theorists and practicing designers from many fields, who can bring valuable perspectives to the discipline. While interdisciplinary connections between biologists and engineers have built synthetic biology via the science and the technology of biology, interdisciplinary collaboration with artists, designers, and social theorists can provide insight on the connections between technology and society. Such collaborations can open up new avenues and new principles for research and design, as well as shed new light on the challenging context-dependence-both biological and social-that face living technologies at many scales. This review is inspired by the session titled "Design and Synthetic Biology: Connecting People and Technology" at Synthetic Biology 6.0 and covers a range of literature on design practice in synthetic biology and beyond. Critical engagement with how design is used to shape the discipline opens up new possibilities for how we might design the future of synthetic biology.

Ultrathin-skinned asymmetric membranes by immiscible solvents treatment

Science.gov (United States)

Friesen, Dwayne T.; Babcock, Walter C.

1989-01-01

Improved semipermeable asymmetric fluid separation membranes useful in gas, vapor and liquid separations are disclosed. The membranes are prepared by substantially filling the pores of asymmetric cellulosic semipermeable membranes having a finely porous layer on one side thereof with a water immiscible organic liquid, followed by contacting the finely porous layer with water.

Asymmetric conditional volatility in international stock markets

Science.gov (United States)

Ferreira, Nuno B.; Menezes, Rui; Mendes, Diana A.

2007-08-01

Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the SP 500, FTSE 100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of changes in macroeconomic variables, we find no significant evidence of asymmetric behaviour of the stock market returns. There are some signs that the Portuguese Stock Market tends to show somewhat less market efficiency than other markets since the effect of the shocks appear to take a longer time to dissipate.

Salt supply to and significance of asymmetric salt diapirs

DEFF Research Database (Denmark)

Koyi, H.; Burliga, S.; Chemia, Zurab

2012-01-01

Salt diapirs can be asymmetric both internally and externally reflecting their evolution history. As such, this asymmetry bear a significant amount of information about the differential loading (± lateral forces) and in turn the salt supply that have shaped the diapir. In two dimensions......, In this study we compare results of analogue and numerical models of diapirs with two natural salt diapris (Klodawa and Gorleben diapirs) to explain their salt supply and asymmetric evolution. In a NW-SE section, the Gorleben salt diapir possesses an asymmetric external geometry represented by a large...... southeastern overhang due to salt extrusion during Middle Cretaceous followed by its burial in Tertiary. This external asymmetry is also reflected in the internal configuration of the diapir which shows different rates of salt flow on the two halves of the structure. The asymmetric external and internal...

Two-channel totally asymmetric simple exclusion processes

International Nuclear Information System (INIS)

Pronina, Ekaterina; Kolomeisky, Anatoly B

2004-01-01

Totally asymmetric simple exclusion processes, consisting of two coupled parallel lattice chains with particles interacting with hard-core exclusion and moving along the channels and between them, are considered. In the limit of strong coupling between the channels, the particle currents, density profiles and a phase diagram are calculated exactly by mapping the system into an effective one-channel totally asymmetric exclusion model. For intermediate couplings, a simple approximate theory, that describes the particle dynamics in vertical clusters of two corresponding parallel sites exactly and neglects the correlations between different vertical clusters, is developed. It is found that, similarly to the case of one-channel totally asymmetric simple exclusion processes, there are three stationary state phases, although the phase boundaries and stationary properties strongly depend on inter-channel coupling. Extensive computer Monte Carlo simulations fully support the theoretical predictions

Appropriate quantization of asymmetric games with continuous strategies

International Nuclear Information System (INIS)

Qin Gan; Chen Xi; Sun Min; Zhou Xianyi; Du Jiangfeng

2005-01-01

We establish a new quantization scheme to study the asymmetric Bertrand duopoly with differentiated products. This scheme is more efficient than the previous symmetric one because it can exactly make the optimal cooperative payoffs at quantum Nash equilibrium. It is also a necessary condition for general asymmetric games with continuous strategies to reach such payoffs

Asymmetric forecasting and commitment policy in a robust control problem

OpenAIRE

Taro Ikeda

2013-01-01

This paper provides a piece of results regarding asymmetric forecasting and commitment monetary policy with a robust control algorithm. Previous studies provide no clarification of the connection between asymmetric preference and robust commitment policy. Three results emerge from general equilibrium modeling with asymmetric preference: (i) the condition for system stability implies an average inflation bias with respect to asymmetry (ii) the effect of asymmetry can be mitigated if policy mak...

Impact of Secondary Interactions in Asymmetric Catalysis

OpenAIRE

Frölander, Anders

2007-01-01

This thesis deals with secondary interactions in asymmetric catalysis and their impact on the outcome of catalytic reactions. The first part revolves around the metal-catalyzed asymmetric allylic alkylation reaction and how interactions within the catalyst affect the stereochemistry. An OH–Pd hydrogen bond in Pd(0)–π-olefin complexes of hydroxy-containing oxazoline ligands was identified by density functional theory computations and helped to rationalize the contrasting results obtained emplo...

How Is Nature Asymmetric?

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 6. How Is Nature Asymmetric? - Discrete Symmetries in Particle Physics and their Violation ... Indian Institute of Technology, Chennai. Aligarh Muslim University. University of Rajasthan, Jaipur. Indian Institute of Science, Bangalore 560012, India.

Exploring asymmetric catalytic transformations

NARCIS (Netherlands)

Guduguntla, Sureshbabu

2017-01-01

In Chapter 2, we report a highly enantioselective synthesis of β-alkyl-substituted alcohols through a one-pot Cu- catalyzed asymmetric allylic alkylation with organolithium reagents followed by reductive ozonolysis. The synthesis of γ-alkyl-substituted alcohols was also achieved through Cu-catalyzed

Simulation of Phenix EOL Asymmetric Test

Energy Technology Data Exchange (ETDEWEB)

Ha, Kwi Seok; Lee, Kwi Lim; Choi, Chi Woong; Kang, Seok Hun; Chang, Won Pyo; Jeong, Hae Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

The asymmetric test of End-Of-Life (EOL) tests on the Phenix plant was used for the evaluation of the MARS-LMR in the Generation IV frame as a part of the code validation. The purpose of the test is to evaluate the ability of the system code to describe asymmetric situations and to identify important phenomena during asymmetrical transient such as a three dimensional effect, buoyancy influence, and thermal stratification in the hot and cold pools. 3-dimensional sodium coolant mixing in the pools has different characteristics from the one dimensional full instantaneous mixing. The velocities and temperatures at the core outlet level differ at each sub-assembly and the temperature in the center of the hot pool may be high because the driver fuels are located at the center region. The temperatures in the hot pool are not the same in the radial and axial locations due to the buoyancy effect. The temperatures in the cold pool also differ along with the elevations and azimuthal directions due to the outlet location of IHX and the thermal stratification

Flatfish: an asymmetric perspective on metamorphosis.

Science.gov (United States)

Schreiber, Alexander M

2013-01-01

The most asymmetrically shaped and behaviorally lateralized of all the vertebrates, the flatfishes are an endless source of fascination to all fortunate enough to study them. Although all vertebrates undergo left-right asymmetric internal organ placement during embryogenesis, flatfish are unusual in that they experience an additional period of postembryonic asymmetric remodeling during metamorphosis, and thus deviate from a bilaterally symmetrical body plan more than other vertebrates. As with amphibian metamorphosis, all the developmental programs of flatfish metamorphosis are ultimately under the control of thyroid hormone. At least one gene pathway involved in embryonic organ lateralization (nodal-lefty-pitx2) is re-expressed in the larval stage during flatfish metamorphosis. Aspects of modern flatfish ontogeny, such as the gradual translocation of one eye to the opposite side of the head and the appearance of key neurocranial elements during metamorphosis, seem to elegantly recapitulate flatfish phylogeny. This chapter highlights the current state of knowledge of the developmental biology of flatfish metamorphosis with emphases on the genetic, morphological, behavioral, and evolutionary origins of flatfish asymmetry. Copyright © 2013 Elsevier Inc. All rights reserved.

Standards vs. labels with imperfect competition and asymmetric information

DEFF Research Database (Denmark)

Baltzer, Kenneth Thomas

2012-01-01

I demonstrate that providing information about product quality is not necessarily the best way to address asymmetric information problems when markets are imperfectly competitive. In a vertical differentiation model I show that a Minimum Quality Standard, which retains asymmetric information...

Standards vs. labels with imperfect competition and asymmetric information

DEFF Research Database (Denmark)

Baltzer, Kenneth Thomas

I demonstrate that providing information about product quality is not necessarily the best way to address asymmetric information problems when markets are imperfectly competitive. In a vertical dierentiation model I show that a Minimum Quality Standard, which retains asymmetric information...

Asymmetrical Polymer Vesicles for Drug delivery and Other Applications

Directory of Open Access Journals (Sweden)

Yi Zhao

2017-06-01

Full Text Available Scientists have been attracted by polymersomes as versatile drug delivery systems since the last two decades. Polymersomes have the potential to be versatile drug delivery systems because of their tunable membrane formulations, stabilities in vivo, various physicochemical properties, controlled release mechanisms, targeting abilities, and capacities to encapsulate a wide range of drugs and other molecules. Asymmetrical polymersomes are nano- to micro-sized polymeric capsules with asymmetrical membranes, which means, they have different outer and inner coronas so that they can exhibit better endocytosis rate and endosomal escape ability than other polymeric systems with symmetrical membranes. Hence, asymmetrical polymersomes are highly promising as self-assembled nano-delivery systems in the future for in vivo therapeutics delivery and diagnostic imaging applications. In this review, we prepared a summary about recent research progresses of asymmetrical polymersomes in the following aspects: synthesis, preparation, applications in drug delivery and others.

Exploiting nanospace for asymmetric catalysis: confinement of immobilized, single-site chiral catalysts enhances enantioselectivity.

Science.gov (United States)

Thomas, John Meurig; Raja, Robert

2008-06-01

In the mid-1990s, it became possible to prepare high-area silicas having pore diameters controllably adjustable in the range ca. 20-200 Å. Moreover, the inner walls of these nanoporous solids could be functionalized to yield single-site, chiral, catalytically active organometallic centers, the precise structures of which could be determined using in situ X-ray absorption and FTIR and multinuclear magic angle spinning (MAS) NMR spectroscopy. This approach opened up the prospect of performing heterogeneous enantioselective conversions in a novel manner, under the spatial restrictions imposed by the nanocavities within which the reactions occur. In particular, it suggested an alternative method for preparing pharmaceutically and agrochemically useful asymmetric products by capitalizing on the notion, initially tentatively perceived, that spatial confinement of prochiral reactants (and transition states formed at the chiral active center) would provide an altogether new method of boosting the enantioselectivity of the anchored chiral catalyst. Initially, we anchored chiral single-site heterogeneous catalysts to nanopores covalently via a ligand attached to Pd(II) or Rh(I) centers. Later, we employed a more convenient and cheaper electrostatic method, relying in part on strong hydrogen bonding. This Account provides many examples of these processes, encompassing hydrogenations, oxidations, and aminations. Of particular note is the facile synthesis from methyl benzoylformate of methyl mandelate, which is a precursor in the synthesis of pemoline, a stimulant of the central nervous system; our procedure offers several viable methods for reducing ketocarboxylic acids. In addition to relying on earlier (synchrotron-based) in situ techniques for characterizing catalysts, we have constructed experimental procedures involving robotically controlled catalytic reactors that allow the kinetics of conversion and enantioselectivity to be monitored continually, and we have access to

Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project

OpenAIRE

Sliva, Anna; Yang, Huanming; Boeke, Jef D.; Mathews, Debra J. H.

2015-01-01

First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) Project is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with...

Capacitorless one-transistor dynamic random-access memory based on asymmetric double-gate Ge/GaAs-heterojunction tunneling field-effect transistor with n-doped boosting layer and drain-underlap structure

Science.gov (United States)

Yoon, Young Jun; Seo, Jae Hwa; Kang, In Man

2018-04-01

In this work, we present a capacitorless one-transistor dynamic random-access memory (1T-DRAM) based on an asymmetric double-gate Ge/GaAs-heterojunction tunneling field-effect transistor (TFET) for DRAM applications. The n-doped boosting layer and gate2 drain-underlap structure is employed in the device to obtain an excellent 1T-DRAM performance. The n-doped layer inserted between the source and channel regions improves the sensing margin because of a high rate of increase in the band-to-band tunneling (BTBT) probability. Furthermore, because the gate2 drain-underlap structure reduces the recombination rate that occurs between the gate2 and drain regions, a device with a gate2 drain-underlap length (L G2_D-underlap) of 10 nm exhibited a longer retention performance. As a result, by applying the n-doped layer and gate2 drain-underlap structure, the proposed device exhibited not only a high sensing margin of 1.11 µA/µm but also a long retention time of greater than 100 ms at a temperature of 358 K (85 °C).

Deliberate ROS production and auxin synergistically trigger the asymmetrical division generating the subsidiary cells in Zea mays stomatal complexes.

Science.gov (United States)

Livanos, Pantelis; Galatis, Basil; Apostolakos, Panagiotis

2016-07-01

Subsidiary cell generation in Poaceae is an outstanding example of local intercellular stimulation. An inductive stimulus emanates from the guard cell mother cells (GMCs) towards their laterally adjacent subsidiary cell mother cells (SMCs) and triggers the asymmetrical division of the latter. Indole-3-acetic acid (IAA) immunolocalization in Zea mays protoderm confirmed that the GMCs function as local sources of auxin and revealed that auxin is polarly accumulated between GMCs and SMCs in a timely-dependent manner. Besides, staining techniques showed that reactive oxygen species (ROS) exhibit a closely similar, also time-dependent, pattern of appearance suggesting ROS implication in subsidiary cell formation. This phenomenon was further investigated by using the specific NADPH-oxidase inhibitor diphenylene iodonium, the ROS scavenger N-acetyl-cysteine, menadione which leads to ROS overproduction, and H2O2. Treatments with diphenylene iodonium, N-acetyl-cysteine, and menadione specifically blocked SMC polarization and asymmetrical division. In contrast, H2O2 promoted the establishment of SMC polarity and subsequently subsidiary cell formation in "younger" protodermal areas. Surprisingly, H2O2 favored the asymmetrical division of the intervening cells of the stomatal rows leading to the creation of extra apical subsidiary cells. Moreover, H2O2 altered IAA localization, whereas synthetic auxin analogue 1-napthaleneacetic acid enhanced ROS accumulation. Combined treatments with ROS modulators along with 1-napthaleneacetic acid or 2,3,5-triiodobenzoic acid, an auxin efflux inhibitor, confirmed the crosstalk between ROS and auxin functioning during subsidiary cell generation. Collectively, our results demonstrate that ROS are critical partners of auxin during development of Z. mays stomatal complexes. The interplay between auxin and ROS seems to be spatially and temporarily regulated.

Diastereoselective Spiroannulation of Phenolic Substrates: Advances Towards the Asymmetric Formation of the Manumycin m-C7N Core Skeleton

Directory of Open Access Journals (Sweden)

Thomas W. Scully

2007-09-01

Full Text Available The asymmetric syntheses of two new spirolactones prepared in optically pure form from L-3-nitrotyrosine are described. The key step, an oxidative spiroannulation, was carried out on the optically active phenols 11a and 11b and afforded the new spirolactones 5a and 5b in 85% and 83% yields, respectively, as mixtures (3:1 dr of diastereomers. The major diastereomers from these mixtures could be isolated in optically pure form by trituration using acetone-hexanes as the solvent. Thus, the optically active spirolactones (+-5a (+ 92.8o, c=0.125 acetone and (+-5b (+112.0o, c= 0.125 acetone were obtained after four synthetic steps from L-3-nitrotyrosine in 41% and 43% yield, respectively.

Cell Chirality Drives Left-Right Asymmetric Morphogenesis.

Science.gov (United States)

Inaki, Mikiko; Sasamura, Takeshi; Matsuno, Kenji

2018-01-01

Most macromolecules found in cells are chiral, meaning that they cannot be superimposed onto their mirror image. However, cells themselves can also be chiral, a subject that has received little attention until very recently. In our studies on the mechanisms of left-right (LR) asymmetric development in Drosophila , we discovered that cells can have an intrinsic chirality to their structure, and that this "cell chirality" is generally responsible for the LR asymmetric development of certain organs in this species. The actin cytoskeleton plays important roles in the formation of cell chirality. In addition, Myosin31DF ( Myo31DF ), which encodes Drosophila Myosin ID, was identified as a molecular switch for cell chirality. In other invertebrate species, including snails and Caenorhabditis elegans , chirality of the blastomeres, another type of cell chirality, determines the LR asymmetry of structures in the body. Thus, chirality at the cellular level may broadly contribute to LR asymmetric development in various invertebrate species. Recently, cell chirality was also reported for various vertebrate cultured cells, and studies suggested that cell chirality is evolutionarily conserved, including the essential role of the actin cytoskeleton. Although the biological roles of cell chirality in vertebrates remain unknown, it may control LR asymmetric development or other morphogenetic events. The investigation of cell chirality has just begun, and this new field should provide valuable new insights in biology and medicine.

Use of nonlinear asymmetrical shock absorber to improve comfort on passenger vehicles

Science.gov (United States)

Silveira, M.; Pontes, B. R.; Balthazar, J. M.

2014-03-01

In this study the behaviour of two different types of shock absorbers, symmetrical (linear) and asymmetrical (nonlinear) is compared for use on passenger vehicles. The analyses use different standard road inputs and include variation of the severity parameter, the asymmetry ratio and the velocity of the vehicle. Performance indices and acceleration values are used to assess the efficacy of the asymmetrical systems. The comparisons show that the asymmetrical system, with nonlinear characteristics, tends to have a smoother and more progressive performance, both for vertical and angular movements. The half-car front asymmetrical system was introduced, and the simulation results show that the use of the asymmetrical system only at the front of the vehicle can further diminish the angular oscillations. As lower levels of acceleration are essential for improved ride comfort, the use of asymmetrical systems for vibrations and impact absorption can be a more advantageous choice for passenger vehicles.

Performance of JPEG Image Transmission Using Proposed Asymmetric Turbo Code

Directory of Open Access Journals (Sweden)

Siddiqi Mohammad Umar

2007-01-01

Full Text Available This paper gives the results of a simulation study on the performance of JPEG image transmission over AWGN and Rayleigh fading channels using typical and proposed asymmetric turbo codes for error control coding. The baseline JPEG algorithm is used to compress a QCIF ( "Suzie" image. The recursive systematic convolutional (RSC encoder with generator polynomials , that is, (13/11 in decimal, and 3G interleaver are used for the typical WCDMA and CDMA2000 turbo codes. The proposed asymmetric turbo code uses generator polynomials , that is, (13/11; 13/9 in decimal, and a code-matched interleaver. The effect of interleaver in the proposed asymmetric turbo code is studied using weight distribution and simulation. The simulation results and performance bound for proposed asymmetric turbo code for the frame length , code rate with Log-MAP decoder over AWGN channel are compared with the typical system. From the simulation results, it is observed that the image transmission using proposed asymmetric turbo code performs better than that with the typical system.

Characterization of Thermal Stability of Synthetic and Semi-Synthetic Engine Oils

Directory of Open Access Journals (Sweden)

Anand Kumar Tripathi

2015-03-01

Full Text Available Engine oils undergo oxidative degradation and wears out during service. Hence it is important to characterize ageing of engine oils at different simulated conditions to evaluate the performance of existing oils and also design new formulations. This work focuses on characterizing the thermo-oxidative degradation of synthetic and semi-synthetic engine oils aged at 120, 149 and 200 °C. Apparent activation energy of decomposition of aged oils evaluated using the isoconversional Kissinger-Akahira-Sunose technique was used as a thermal stability marker. The temporal variation of stability at different ageing temperatures was corroborated with kinematic viscosity, oxidation, sulfation and nitration indices, total base number, antiwear additive content and molecular structure of the organic species present in the oils. At the lowest temperature employed, synthetic oil underwent higher rate of oxidation, while semi-synthetic oil was stable for longer time periods. At higher temperatures, the initial rate of change of average apparent activation energy of synthetic oil correlated well with a similar variation in oxidation number. A mixture of long chain linear, branched, and cyclic hydrocarbons were observed when semi-synthetic oil was degraded at higher temperatures.

Asymmetric Modeling of the Industrial Heavy Water Plant (PIAP)

International Nuclear Information System (INIS)

Teruel, Federico; Aprea, J; Guido Lavalle, German

2000-01-01

Software of asymmetric stationary simulation for the Industrial Heavy Water Plant (PIAP) was developed, based on an existing symmetric simulator (Brigitte 2.0).This software allows to turn off some of the isotopic enrichment twin units present in the plant and to simulate them asymmetrically, in other words, with different selection of parameters between twins.Other incorporations were done, such as passing flows between units and entering flows in strategic points of the plant.The iterative system in which the symmetric simulator is based was insufficient to develop the asymmetric simulator, so the system was modeled according to an implicit scheme for the units that form the simulator.This type of resolution resulted in a simulator that supports a big range of boundary conditions and internal parameters.Moreover, the time of calculus is short (∼3 minutes), making it actually useful.The asymmetric simulator is at the PIAP now, for its study and validation. It shows expected tendencies and results according to the symmetric simulator already validated

The Asymmetric Implementation of the European Banking Union (EBU: Consequences for Financial Stability

Directory of Open Access Journals (Sweden)

Vollmer Uwe

2016-06-01

Full Text Available EU Member States outside the Eurozone are hesitating to enter the European Banking Union (EBU and to establish “close cooperation” in bank supervision with the ECB. This paper analyzes the consequences of such asymmetric integration for financial stability in Europe. It argues that the main obstacles against establishing close cooperation are a lack of voting rights and insufficient access to the fiscal backstop provided by the European Stability Mechanism (ESM. The paper presents arguments as to why international cooperation in bank supervision could be welfare improving, if multinational banks are dominant. It also discusses suitable reform options for making it more attractive for EU Member States to begin a close cooperation with the ECB.

Experimental and theoretical study on minimum achievable foil thickness during asymmetric rolling.

Directory of Open Access Journals (Sweden)

Delin Tang

Full Text Available Parts produced by microforming are becoming ever smaller. Similarly, the foils required in micro-machines are becoming ever thinner. The asymmetric rolling technique is capable of producing foils that are thinner than those produced by the conventional rolling technique. The difference between asymmetric rolling and conventional rolling is the 'cross-shear' zone. However, the influence of the cross-shear zone on the minimum achievable foil thickness during asymmetric rolling is still uncertain. In this paper, we report experiments designed to understand this critical influencing factor on the minimum achievable thickness in asymmetric rolling. Results showed that the minimum achievable thickness of rolled foils produced by asymmetric rolling with a rolling speed ratio of 1.3 can be reduced to about 30% of that possible by conventional rolling technique. Furthermore, the minimum achievable thickness during asymmetric rolling could be correlated to the cross-shear ratio, which, in turn, could be related to the rolling speed ratio. From the experimental results, a formula to calculate the minimum achievable thickness was established, considering the parameters cross-shear ratio, friction coefficient, work roll radius, etc. in asymmetric rolling.

Experimental and theoretical study on minimum achievable foil thickness during asymmetric rolling.

Science.gov (United States)

Tang, Delin; Liu, Xianghua; Song, Meng; Yu, Hailiang

2014-01-01

Parts produced by microforming are becoming ever smaller. Similarly, the foils required in micro-machines are becoming ever thinner. The asymmetric rolling technique is capable of producing foils that are thinner than those produced by the conventional rolling technique. The difference between asymmetric rolling and conventional rolling is the 'cross-shear' zone. However, the influence of the cross-shear zone on the minimum achievable foil thickness during asymmetric rolling is still uncertain. In this paper, we report experiments designed to understand this critical influencing factor on the minimum achievable thickness in asymmetric rolling. Results showed that the minimum achievable thickness of rolled foils produced by asymmetric rolling with a rolling speed ratio of 1.3 can be reduced to about 30% of that possible by conventional rolling technique. Furthermore, the minimum achievable thickness during asymmetric rolling could be correlated to the cross-shear ratio, which, in turn, could be related to the rolling speed ratio. From the experimental results, a formula to calculate the minimum achievable thickness was established, considering the parameters cross-shear ratio, friction coefficient, work roll radius, etc. in asymmetric rolling.

Asymmetric synthesis II more methods and applications

CERN Document Server

Christmann, Mathias

2012-01-01

After the overwhelming success of 'Asymmetric Synthesis - The Essentials', narrating the colorful history of asymmetric synthesis, this is the second edition with latest subjects and authors. While the aim of the first edition was mainly to honor the achievements of the pioneers in asymmetric syntheses, the aim of this new edition was bringing the current developments, especially from younger colleagues, to the attention of students. The format of the book remained unchanged, i.e. short conceptual overviews by young leaders in their field including a short biography of the authors. The growing multidisciplinary research within chemistry is reflected in the selection of topics including metal catalysis, organocatalysis, physical organic chemistry, analytical chemistry, and its applications in total synthesis. The prospective reader of this book is a graduate or undergraduate student of advanced organic chemistry as well as the industrial chemist who wants to get a brief update on the current developments in th...

Oxide nanomaterials: synthetic developments, mechanistic studies, and technological innovations.

Science.gov (United States)

Patzke, Greta R; Zhou, Ying; Kontic, Roman; Conrad, Franziska

2011-01-24

Oxide nanomaterials are indispensable for nanotechnological innovations, because they combine an infinite variety of structural motifs and properties with manifold morphological features. Given that new oxide materials are almost reported on a daily basis, considerable synthetic and technological work remains to be done to fully exploit this ever increasing family of compounds for innovative nano-applications. This calls for reliable and scalable preparative approaches to oxide nanomaterials and their development remains a challenge for many complex nanostructured oxides. Oxide nanomaterials with special physicochemical features and unusual morphologies are still difficult to access by classic synthetic pathways. The limitless options for creating nano-oxide building blocks open up new technological perspectives with the potential to revolutionize areas ranging from data processing to biocatalysis. Oxide nanotechnology of the 21st century thus needs a strong interplay of preparative creativity, analytical skills, and new ideas for synergistic implementations. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Asymmetric Effects on Escape Rates of Bistable System

International Nuclear Information System (INIS)

Wang Canjun; Mei Dongcheng; Dai Zucheng

2011-01-01

The asymmetric effects on the escape rates from the stable states x ± in the bistable system are analyzed. The results indicate that the multiplicative noise and the additive noise always enhance the particle escape from stable states x ± of bistable. However, the asymmetric parameter r enhances the particle escape from stable state x + , and holds back the particle escape from stable state x - . (general)

Diagnostic implications of asymmetrical mammographic patterns

International Nuclear Information System (INIS)

Asenjo, M.; Ania, B.J.

1997-01-01

To analyze the effect of asymmetrical mammographic patterns of the diagnosis of breast cancer. In a series of 6, 476 patients referred to a Breast Imaging Diagnosis Unit, we excluded males, women with previous breast surgery, and cases in which mammography was not performed, which left 5,203 women included. Each breast was classified according to one of four patterns of mammographic parenchymal density. Asymmetry was considered to exist when a patient's breasts had different patterns. Breast cancer was confirmed histologically in 282 (5.4%) women. The mammographic pattern was asymmetrical in 8% of the women with cancer and in 2% of the women without cancer (p<0.001). Fine-needle aspiration biopsy was performed in 78% and 96% (p=0.04), respectively, of the women with and without mammographic asymmetry who had neoplasms, and in 33% and 22% (p=0.02), respectively, of the women with and without mammographic asymmetry who did not have neoplasms. Asymmetrical mammographic pattern was four times more frequent in the women with breast cancer. This asymmetry decreased the frequency of needle biopsy in women with cancer, but increased the frequency of needle biopsy in women without cancer. (Author) 11 refs

Uncovering the link between malfunctions in Drosophila neuroblast asymmetric cell division and tumorigenesis

Directory of Open Access Journals (Sweden)

Kelsom Corey

2012-11-01

Full Text Available Abstract Asymmetric cell division is a developmental process utilized by several organisms. On the most basic level, an asymmetric division produces two daughter cells, each possessing a different identity or fate. Drosophila melanogaster progenitor cells, referred to as neuroblasts, undergo asymmetric division to produce a daughter neuroblast and another cell known as a ganglion mother cell (GMC. There are several features of asymmetric division in Drosophila that make it a very complex process, and these aspects will be discussed at length. The cell fate determinants that play a role in specifying daughter cell fate, as well as the mechanisms behind setting up cortical polarity within neuroblasts, have proved to be essential to ensuring that neurogenesis occurs properly. The role that mitotic spindle orientation plays in coordinating asymmetric division, as well as how cell cycle regulators influence asymmetric division machinery, will also be addressed. Most significantly, malfunctions during asymmetric cell division have shown to be causally linked with neoplastic growth and tumor formation. Therefore, it is imperative that the developmental repercussions as a result of asymmetric cell division gone awry be understood.

Using Agent Based Distillation to Explore Issues Related to Asymmetric Warfare

Science.gov (United States)

2009-10-01

official definition of asymmetric warfare , considering that its use was redundant to irregular warfare [30]. 2 Such as the Lanchester Equations...RTP-MP-MSG-069 23 - 1 Using Agent Based Distillation to Explore Issues Related to Asymmetric Warfare Martin Adelantado, Jean-Michel Mathé...shows that both conventional and asymmetric warfare are characterised by nonlinear behaviours and that engagement is a Complex Adaptive System (CAS

Controllable asymmetric transmission via gap-tunable acoustic metasurface

Science.gov (United States)

Liu, Bingyi; Jiang, Yongyuan

2018-04-01

In this work, we utilize the acoustic gradient metasurface (AGM) of a bilayer configuration to realize the controllable asymmetric transmission. Relying on the adjustable gap between the two composing layers, the metasurface could switch from symmetric transmission to asymmetric transmission at a certain gap value. The underlying mechanism is attributed to the interference between the forward diffracted waves scattered by the surface bound waves at two air-AGM interfaces, which is apparently influenced by the interlayer distance. We further utilize the hybrid acoustic elements to construct the desired gradient metasurface with a tunable gap and validate the controllable asymmetric transmission with full-wave simulations. Our work provides the solution for actively controlling the transmission property of an acoustic element, which shows potential application in acoustic communication as a dynamic tunable acoustic diode.

Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 2: aldol, Mannich addition reactions, deracemization and (S) to (R) interconversion of α-amino acids.

Science.gov (United States)

Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim

2013-11-01

This review provides a comprehensive treatment of literature data dealing with asymmetric synthesis of α-amino-β-hydroxy and α,β-diamino acids via homologation of chiral Ni(II) complexes of glycine Schiff bases using aldol and Mannich-type reactions. These reactions proceed with synthetically useful chemical yields and thermodynamically controlled stereoselectivity and allow direct introduction of two stereogenic centers in a single operation with predictable stereochemical outcome. Furthermore, new application of Ni(II) complexes of α-amino acids Schiff bases for deracemization of racemic α-amino acids and (S) to (R) interconversion providing additional synthetic opportunities for preparation of enantiomerically pure α-amino acids, is also reviewed. Origin of observed diastereo-/enantioselectivity in the aldol, Mannich-type and deracemization reactions, generality and limitations of these methodologies are critically discussed.

Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project.

Science.gov (United States)

Sliva, Anna; Yang, Huanming; Boeke, Jef D; Mathews, Debra J H

2015-08-01

First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) PROJECT is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 PROJECT: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms. Copyright © 2015 by the Genetics Society of America.

Water Spray Flow Characteristics Under Synthetic Jet Driven By a Piezoelectric Actuator

Science.gov (United States)

Marchitto, L.; Valentino, G.; Chiatto, M.; de Luca, L.

2017-01-01

Particle Image Velocimetry (PIV) and Phase Doppler Anemometry (PDA) have been applied to investigate the droplets size and velocity distribution of a water spray, under the control of a piezo-element driven synthetic jet (SJ). Tests were carried out under atmospheric conditions within a chamber test rig equipped with optical accesses at two injection pressures, namely 5 and 10 MPa, exploring the variation of the main spray parameters caused by the synthetic jet perturbations. The SJ orifice has been placed at 45° with respect to the water spray axis; the nozzle body has been moved on its own axis and three different nozzle quotes were tested. PIV measurements have been averaged on 300 trials whereas about 105 samples have been acquired for the PDA tests. For each operative condition, the influence region of the SJ device on the spray has been computed through a T-Test algorithm. The synthetic jet locally interacts with the spray, energizing the region downstream the impact. The effect of the actuator decreases at higher injection pressures and moving the impact region upwards. Droplets coalescence can be detected along the synthetic jet axis, while no significant variations are observed along a direction orthogonal to it.

Study on the output factors of asymmetrical rectangular electron beam field

International Nuclear Information System (INIS)

Chen Yinghai; Yang Yueqin; Ma Yuhong; Zheng Jin; Zou Lijuan

2009-01-01

Objective: To evaluate the variant regularity of the output factors of asymmetrical rectangular electron beam field. Methods: The output factors of three special fields with different applicators and energies were measured by ionization chamber method at different off-axis distances. Then deviations of the output factors between asymmetrical and symmetric rectangular fields were calculated. Results: The changes of output factor with different off-axis distances in asymmetrical rectangular fields were basically consistent with those in standard square fields with the same applicator. It revealed that the output factor of asymmetrical rectangular field was related with the off-axis ratio of standard square field. Applicator and field size did not show obvious influence on the output factor. Conclusions: The output factor changes of asymmetrical rectangular field are mainly correlated with the off-axis ratio of standard square field. The correction of the output factor is determined by the off-axis ratio changes in standard square field. (authors)

Accessibility and usability OCW data: The UTPL OCW

Directory of Open Access Journals (Sweden)

Germania Rodríguez

2017-08-01

Full Text Available This data article provides a data description on article entitled “A framework for improving web accessibility and usability of Open Course Ware sites” [3] This Data in Brief presents the data obtained from the accessibility and usability evaluation of the UTPL OCW. The data obtained from the framework evaluation consists of the manual evaluation of the standards criteria and the automatic evaluation of the tools Google PageSpeed and Google Analytics. In addition, this article presents the synthetized tables from standards that are used by the framework to evaluate the accessibility and usability of OCW, and the questionnaires required to extract the data. As a result, the article also provides the data required to reproduce the evaluation of other OCW.

Success Factors of Asymmetric Connections - Example of Large Slovenian Enterprises

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Viktor Vračar

2014-11-01

Full Text Available More and more companies realize the fact that networking or partner collaborations, which are based on partner relations between companies, are essential for their long-term existence. In today’s global competitive environment each company is included at least in some different connections. Very common connections occur between large and smaller enterprises, where the so called asymmetric connections occur, which may be understood as the ability of one organisation to establish power, influence and control over the other organisation and its resources. According to numerous statements, the connections between enterprises are very frequently uneffectivenessful, with opinions on the optimal nature of asymmetric connections being quite common as well, whereby it is, as a rule, a synergic complementing of missing content for both partners. To verify the thesis, that companies achieve more competitiveness and effectiveness through connections, whereby the so called asymmetric connections are common, a structural model of the evolution of asymmetric connection has been developed, which connects the theoretically identified factors and all dependent concepts of competitiveness, efficiency and effectiveness. The empirical research also attempts to further expose the factors of asymmetric connections, which affect efficiency and effectiveness of the connected enterprises.

Symmetrization of the beam-beam interaction in an asymmetric collider

International Nuclear Information System (INIS)

Chin, Y.H.

1990-07-01

This paper studies the idea of symmetrizing both the lattice and the beams of an asymmetric collider, and discusses why this regime should be within the parametric reach of the design in order to credibly ensure its performance. Also examined is the effectiveness of a simple compensation method using the emittance as a free parameter and that it does not work in all cases. At present, when there are no existing asymmetric colliders, it seems prudent to design an asymmetric collider so as to be similar to a symmetric one (without relying on a particular theory of the asymmetric beam-beam interaction that has not passed tests of fidelity). Nevertheless, one must allow for the maximum possible flexibility and freedom in adjusting those parameters that affect luminosity. Such a parameter flexibility will be essential in tuning the collider to the highest luminosity

Force on an Asymmetric Capacitor

National Research Council Canada - National Science Library

Bahder, Thomas

2003-01-01

.... At present, the physical basis for the Biefeld-Brown effect is not understood. The order of magnitude of the net force on the asymmetric capacitor is estimated assuming two different mechanisms of charge conduction between its electrodes...

Asymmetric synthesis of cyclo-archaeol and ß-glucosyl cyclo-archaeol

NARCIS (Netherlands)

Ferrer, C.; Fodran, P.; Barroso, S.; Gibson, R.; Hopmans, E.C.; Sinninghe Damsté, J.S.; Schouten, S.; Minnaard, A.J.

2013-01-01

An efficient asymmetric synthesis of cyclo-archaeol and beta-glucosyl cyclo-archaeol is presented employing catalytic asymmetric conjugate addition and catalytic epoxide ring opening as the key steps. Their occurrence in deep sea hydrothermal vents has been confirmed by chromatographic comparison

Asymmetric Damage Segregation Constitutes an Emergent Population-Level Stress Response

DEFF Research Database (Denmark)

Vedel, Søren; Nunns, Harry; Košmrlj, Andrej

2016-01-01

Asymmetric damage segregation (ADS) is a mechanism for increasing population fitness through non-random, asymmetric partitioning of damaged macromolecules at cell division. ADS has been reported across multiple organisms, though the measured effects on fitness of individuals are often small. Here...

Asymmetric-cut variable-incident-angle monochromator.

Science.gov (United States)

Smither, R K; Graber, T J; Fernandez, P B; Mills, D M

2012-03-01

A novel asymmetric-cut variable-incident-angle monochromator was constructed and tested in 1997 at the Advanced Photon Source of Argonne National Laboratory. The monochromator was originally designed as a high heat load monochromator capable of handling 5-10 kW beams from a wiggler source. This was accomplished by spreading the x-ray beam out on the surface an asymmetric-cut crystal and by using liquid metal cooling of the first crystal. The monochromator turned out to be a highly versatile monochromator that could perform many different types of experiments. The monochromator consisted of two 18° asymmetrically cut Si crystals that could be rotated about 3 independent axes. The first stage (Φ) rotates the crystal around an axis perpendicular to the diffraction plane. This rotation changes the angle of the incident beam with the surface of the crystal without changing the Bragg angle. The second rotation (Ψ) is perpendicular to the first and is used to control the shape of the beam footprint on the crystal. The third rotation (Θ) controls the Bragg angle. Besides the high heat load application, the use of asymmetrically cut crystals allows one to increase or decrease the acceptance angle for crystal diffraction of a monochromatic x-ray beam and allows one to increase or decrease the wavelength bandwidth of the diffraction of a continuum source like a bending-magnet beam or a normal x-ray-tube source. When the monochromator is used in the doubly expanding mode, it is possible to expand the vertical size of the double-diffracted beam by a factor of 10-15. When this was combined with a bending magnet source, it was possible to generate an 8 keV area beam, 16 mm wide by 26 mm high with a uniform intensity and parallel to 1.2 arc sec that could be applied in imaging experiments.

Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers

Directory of Open Access Journals (Sweden)

Arjunan Govindarajan

2017-06-01

Full Text Available We investigate modulational instability (MI in asymmetric dual-core nonlinear directional couplers incorporating the effects of the differences in effective mode areas and group velocity dispersions, as well as phase- and group-velocity mismatches. Using coupled-mode equations for this system, we identify MI conditions from the linearization with respect to small perturbations. First, we compare the MI spectra of the asymmetric system and its symmetric counterpart in the case of the anomalous group-velocity dispersion (GVD. In particular, it is demonstrated that the increase of the inter-core linear-coupling coefficient leads to a reduction of the MI gain spectrum in the asymmetric coupler. The analysis is extended for the asymmetric system in the normal-GVD regime, where the coupling induces and controls the MI, as well as for the system with opposite GVD signs in the two cores. Following the analytical consideration of the MI, numerical simulations are carried out to explore nonlinear development of the MI, revealing the generation of periodic chains of localized peaks with growing amplitudes, which may transform into arrays of solitons.

Specifications of Standards in Systems and Synthetic Biology: Status and Developments in 2016

Directory of Open Access Journals (Sweden)

Schreiber Falk

2016-09-01

Full Text Available Standards are essential to the advancement of science and technology. In systems and synthetic biology, numerous standards and associated tools have been developed over the last 16 years. This special issue of the Journal of Integrative Bioinformatics aims to support the exchange, distribution and archiving of these standards, as well as to provide centralised and easily citable access to them.

Effects of asymmetrical stance and movement on body rotation in pushing.

Science.gov (United States)

Lee, Yun-Ju; Aruin, Alexander S

2015-01-21

Pushing objects in the presence of body asymmetries could increase the risk of back injury. Furthermore, when the object is heavy, it could exacerbate the effects induced by asymmetrical posture. We investigated how the use of asymmetrical posture and/or upper extremity movement affect vertical torque (Tz) and center of pressure (COP) displacement during pushing. Ten healthy volunteers were instructed to push objects of three different weights using two hands (symmetrical hand use) or one hand (asymmetrical hand use) while standing in symmetrical or asymmetrical foot-positions. The peak values of Tz and COP displacement in the medial-lateral direction (COPML) were analyzed. In cases of isolated asymmetry, changes in the Tz were mainly linked with effects of hand-use whereas effects of foot-position dominated changes in the COPML displacement. In cases of a combined asymmetry, the magnitudes of both Tz and COPML were additive when asymmetrical hand-use and foot-position induced the rotation of the lower and upper body in the same direction or subtractive when asymmetries resulted in the rotation of the body segments in the opposite directions. Moreover, larger Tz and COP displacements were seen when pushing the heavy weight. The results point out the importance of using Tz and COPML to describe the isolated or combined effects of asymmetrical upper extremity movement and asymmetrical posture on body rotation during pushing. Furthermore, it suggests that a proper combination of unilateral arm movement and foot placements could help to reduce body rotation even when pushing heavy objects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Project financing versus corporate financing under asymmetric information

OpenAIRE

Anton Miglo

2008-01-01

In recent years financing through the creation of an independent project company or financing by non-recourse debt has become an important part of corporate decisions. Shah and Thakor (JET, 1987) argue that project financing can be optimal when asymmetric information exists between firm's insiders and market participants. In contrast to that paper, we provide an asymmetric information argument for project financing without relying on corporate taxes, costly information production or an assump...

Asymmetric Shaped-Pattern Synthesis for Planar Antenna Arrays

Directory of Open Access Journals (Sweden)

T. M. Bruintjes

2016-01-01

Full Text Available A procedure to synthesize asymmetrically shaped beam patterns is developed for planar antenna arrays. As it is based on the quasi-analytical method of collapsed distributions, the main advantage of this procedure is the ability to realize a shaped (null-free region with very low ripple. Smooth and asymmetrically shaped regions can be used for Direction-of-Arrival estimation and subsequently for efficient tracking with a single output (fully analog beamformer.

Asymmetric collider

International Nuclear Information System (INIS)

Bharadwaj, V.; Colestock, P.; Goderre, G.; Johnson, D.; Martin, P.; Holt, J.; Kaplan, D.

1993-01-01

The study of CP violation in beauty decay is one of the key challenges facing high energy physics. Much work has not yielded a definitive answer how this study might best be performed. However, one clear conclusion is that new accelerator facilities are needed. Proposals include experiments at asymmetric electron-positron colliders and in fixed-target and collider modes at LHC and SSC. Fixed-target and collider experiments at existing accelerators, while they might succeed in a first observation of the effect, will not be adequate to study it thoroughly. Giomataris has emphasized the potential of a new approach to the study of beauty CP violation: the asymmetric proton collider. Such a collider might be realized by the construction of a small storage ring intersecting an existing or soon-to-exist large synchrotron, or by arranging collisions between a large synchrotron and its injector. An experiment at such a collider can combine the advantages of fixed-target-like spectrometer geometry, facilitating triggering, particle identification and the instrumentation of a large acceptance, while the increased √s can provide a factor > 100 increase in beauty-production cross section compared to Tevatron or HERA fixed-target. Beams crossing at a non-zero angle can provide a small interaction region, permitting a first-level decay-vertex trigger to be implemented. To achieve large √s with a large Lorentz boost and high luminosity, the most favorable venue is the high-energy booster (HEB) at the SSC Laboratory, though the CERN SPS and Fermilab Tevatron are also worth considering

An Evolving Asymmetric Game for Modeling Interdictor-Smuggler Problems

Science.gov (United States)

2016-06-01

ASYMMETRIC GAME FOR MODELING INTERDICTOR-SMUGGLER PROBLEMS by Richard J. Allain June 2016 Thesis Advisor: David L. Alderson Second Reader: W...DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE AN EVOLVING ASYMMETRIC GAME FOR MODELING INTERDICTOR- SMUGGLER PROBLEMS 5. FUNDING NUMBERS 6...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited AN EVOLVING

Two H-mixed Synthetic Indices for the Assessment of Research Performance

Directory of Open Access Journals (Sweden)

Fred Y. Ye.

2010-06-01

Full Text Available The author proposes two h-mixed synthetic indices, S=100×1g(h×CPP and T=100×1g(R×h×CPP, for the assessment of research performance, where CPP stands for citations per publication, h for h-index, and R for R-index, the square root of total number of citations in the Hirsch core (Ch. Like their components that respectively measure average citations of all publications, publication output and impact, and total number of citations in the Hirsch core, the h-mixed synthetic indices S and T use readily accessible data to produce a holistic measurement of academic achievement. Higher values correspond to greater academic achievement. The S and T indices are stratified by values of 100 to indicate varying degrees of achievement, where S<100 or T<100 indicates poor levels.

Asymmetric Penning trap coherent states

International Nuclear Information System (INIS)

Contreras-Astorga, Alonso; Fernandez, David J.

2010-01-01

By using a matrix technique, which allows to identify directly the ladder operators, the coherent states of the asymmetric Penning trap are derived as eigenstates of the appropriate annihilation operators. They are compared with those obtained through the displacement operator method.

Asymmetric threat data mining and knowledge discovery

Science.gov (United States)

Gilmore, John F.; Pagels, Michael A.; Palk, Justin

2001-03-01

Asymmetric threats differ from the conventional force-on- force military encounters that the Defense Department has historically been trained to engage. Terrorism by its nature is now an operational activity that is neither easily detected or countered as its very existence depends on small covert attacks exploiting the element of surprise. But terrorism does have defined forms, motivations, tactics and organizational structure. Exploiting a terrorism taxonomy provides the opportunity to discover and assess knowledge of terrorist operations. This paper describes the Asymmetric Threat Terrorist Assessment, Countering, and Knowledge (ATTACK) system. ATTACK has been developed to (a) data mine open source intelligence (OSINT) information from web-based newspaper sources, video news web casts, and actual terrorist web sites, (b) evaluate this information against a terrorism taxonomy, (c) exploit country/region specific social, economic, political, and religious knowledge, and (d) discover and predict potential terrorist activities and association links. Details of the asymmetric threat structure and the ATTACK system architecture are presented with results of an actual terrorist data mining and knowledge discovery test case shown.

Synthetic environments

Science.gov (United States)

Lukes, George E.; Cain, Joel M.

1996-02-01

The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.

Chiral 1,3,2-oxazaborolidines in asymmetric synthesis: recent advances

International Nuclear Information System (INIS)

Glushkov, Vladimir A; Tolstikov, Alexander G

2004-01-01

The use of chiral 1,3,2-oxazaborolidines in asymmetric organic synthesis, particularly, in enantioselective reduction of ketones, imines and oxime ethers, asymmetric Diels-Alder reactions, aldol condensation and atroposelective reduction of lactones is reviewed. Reactions of immobilised 1,3,2-oxazaborolidines are also considered.

Holding-time-aware asymmetric spectrum allocation in virtual optical networks

Science.gov (United States)

Lyu, Chunjian; Li, Hui; Liu, Yuze; Ji, Yuefeng

2017-10-01

Virtual optical networks (VONs) have been considered as a promising solution to support current high-capacity dynamic traffic and achieve rapid applications deployment. Since most of the network services (e.g., high-definition video service, cloud computing, distributed storage) in VONs are provisioned by dedicated data centers, needing different amount of bandwidth resources in both directions, the network traffic is mostly asymmetric. The common strategy, symmetric provisioning of traffic in optical networks, leads to a waste of spectrum resources in such traffic patterns. In this paper, we design a holding-time-aware asymmetric spectrum allocation module based on SDON architecture and an asymmetric spectrum allocation algorithm based on the module is proposed. For the purpose of reducing spectrum resources' waste, the algorithm attempts to reallocate the idle unidirectional spectrum slots in VONs, which are generated due to the asymmetry of services' bidirectional bandwidth. This part of resources can be exploited by other requests, such as short-time non-VON requests. We also introduce a two-dimensional asymmetric resource model for maintaining idle spectrum resources information of VON in spectrum and time domains. Moreover, a simulation is designed to evaluate the performance of the proposed algorithm, and results show that our proposed asymmetric spectrum allocation algorithm can improve the resource waste and reduce blocking probability.

Asymmetric Price Transmission in Indonesia's Wheat Flour Market

OpenAIRE

Varela, Gonzalo J.; Taniguchi, Kiyoshi

2014-01-01

Data indicate that its domestic price in Indonesia has been increasing regardless of movements in the international price of wheat. A test for asymmetric price transmission from international wheat to domestic wheat flour markets is conducted using an error correction model and find the presence of asymmetric price transmission. The upward adjustment in the domestic price of wheat flour is much faster than its adjustment downward when it deviates from long-run equilibrium. Our results are rob...

Asymmetrical Capacitors for Propulsion and the ISR Asymmetrical Capacitator Thruster, Experimental Results and Improved Designs

Science.gov (United States)

Canning, Francis; Winet, Ed; Ice, Bob; Melcher, Cory; Pesavento, Phil; Holmes, Alan; Butler, Carey; Cole, John; Campbell, Jonathan

2004-01-01

The outline of this viewgraph presentation on asymmetrical capacitor thruster development includes: 1) Test apparatus; 2) Devices tested; 3) Circuits used; 4) Data collected (Time averaged, Time resolved); 5) Patterns observed; 6) Force calculation; 7) Electrostatic modeling; 8) Understand it all.

From design to manufacturing of asymmetric teeth gears using computer application

Science.gov (United States)

Suciu, F.; Dascalescu, A.; Ungureanu, M.

2017-05-01

The asymmetric cylindrical gears, with involutes teeth profiles having different base circle diameters, are nonstandard gears, used with the aim to obtain better function parameters for the active profile. We will expect that the manufacturing of these gears became possible only after the design and realization of some specific tools. The paper present how the computer aided design and applications developed in MATLAB, for obtain the geometrical parameters, in the same time for calculation some functional parameters like stress and displacements, transmission error, efficiency of the gears and the 2D models, generated with AUTOLISP applications, are used for computer aided manufacturing of asymmetric gears with standard tools. So the specific tools considered one of the disadvantages of these gears are not necessary and implicitly the expected supplementary costs are reduced. The calculus algorithm established for the asymmetric gear design application use the „direct design“ of the spur gears. This method offers the possibility of determining first the parameters of the gears, followed by the determination of the asymmetric gear rack’s parameters, based on those of the gears. Using original design method and computer applications have been determined the geometrical parameters, the 2D and 3D models of the asymmetric gears and on the base of these models have been manufacturing on CNC machine tool asymmetric gears.

Totally Asymmetric Limit for Models of Heat Conduction

Science.gov (United States)

De Carlo, Leonardo; Gabrielli, Davide

2017-08-01

We consider one dimensional weakly asymmetric boundary driven models of heat conduction. In the cases of a constant diffusion coefficient and of a quadratic mobility we compute the quasi-potential that is a non local functional obtained by the solution of a variational problem. This is done using the dynamic variational approach of the macroscopic fluctuation theory (Bertini et al. in Rev Mod Phys 87:593, 2015). The case of a concave mobility corresponds essentially to the exclusion model that has been discussed in Bertini et al. (J Stat Mech L11001, 2010; Pure Appl Math 64(5):649-696, 2011; Commun Math Phys 289(1):311-334, 2009) and Enaud and Derrida (J Stat Phys 114:537-562, 2004). We consider here the convex case that includes for example the Kipnis-Marchioro-Presutti (KMP) model and its dual (KMPd) (Kipnis et al. in J Stat Phys 27:6574, 1982). This extends to the weakly asymmetric regime the computations in Bertini et al. (J Stat Phys 121(5/6):843-885, 2005). We consider then, both microscopically and macroscopically, the limit of large externalfields. Microscopically we discuss some possible totally asymmetric limits of the KMP model. In one case the totally asymmetric dynamics has a product invariant measure. Another possible limit dynamics has instead a non trivial invariant measure for which we give a duality representation. Macroscopically we show that the quasi-potentials of KMP and KMPd, which are non local for any value of the external field, become local in the limit. Moreover the dependence on one of the external reservoirs disappears. For models having strictly positive quadratic mobilities we obtain instead in the limit a non local functional having a structure similar to the one of the boundary driven asymmetric exclusion process.

Best Speed Fit EDF Scheduling for Performance Asymmetric Multiprocessors

Directory of Open Access Journals (Sweden)

Peng Wu

2017-01-01

Full Text Available In order to improve the performance of a real-time system, asymmetric multiprocessors have been proposed. The benefits of improved system performance and reduced power consumption from such architectures cannot be fully exploited unless suitable task scheduling and task allocation approaches are implemented at the operating system level. Unfortunately, most of the previous research on scheduling algorithms for performance asymmetric multiprocessors is focused on task priority assignment. They simply assign the highest priority task to the fastest processor. In this paper, we propose BSF-EDF (best speed fit for earliest deadline first for performance asymmetric multiprocessor scheduling. This approach chooses a suitable processor rather than the fastest one, when allocating tasks. With this proposed BSF-EDF scheduling, we also derive an effective schedulability test.

Gravity-induced asymmetric distribution of a plant growth hormone

Science.gov (United States)

Bandurski, R. S.; Schulze, A.; Momonoki, Y.

1984-01-01

Dolk (1936) demonstrated that gravistimulation induced an asymmetric distribution of auxin in a horizontally-placed shoot. An attempt is made to determine where and how that asymmetry arises, and to demonstrate that the endogenous auxin, indole-3-acetic acid, becomes asymmetrically distributed in the cortical cells of the Zea mays mesocotyl during 3 min of geostimulation. Further, indole-3-acetic acid derived by hydrolysis of an applied transport form of the hormone, indole-3-acetyl-myo-inositol, becomes asymmetrically distributed within 15 min of geostimulus time. From these and prior data is developed a working theory that the gravitational stimulus induces a selective leakage, or secretion, of the hormone from the vascular tissue to the cortical cells of the mesocotyl.

Asymmetric acoustic transmission in multiple frequency bands

Energy Technology Data Exchange (ETDEWEB)

Sun, Hong-xiang, E-mail: jsdxshx@ujs.edu.cn [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Laboratory of Modern Acoustics, Institute of Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 (China); Yuan, Shou-qi, E-mail: Shouqiy@ujs.edu.cn [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Zhang, Shu-yi [Laboratory of Modern Acoustics, Institute of Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

2015-11-23

We report both experimentally and numerically that the multi-band device of the asymmetric acoustic transmission is realized by placing two periodic gratings with different periods on both sides of two brass plates immersed in water. The asymmetric acoustic transmission can exist in four frequency bands below 1500 kHz, which arises from the interaction between various diffractions from the two gratings and Lamb modes in the brass plates immersed in water. The results indicate that the device has the advantages of multiple band, broader bandwidth, and simpler structure. Our finding should have great potential applications in ultrasonic devices.

Asymmetric acoustic transmission in multiple frequency bands

International Nuclear Information System (INIS)

Sun, Hong-xiang; Yuan, Shou-qi; Zhang, Shu-yi

2015-01-01

We report both experimentally and numerically that the multi-band device of the asymmetric acoustic transmission is realized by placing two periodic gratings with different periods on both sides of two brass plates immersed in water. The asymmetric acoustic transmission can exist in four frequency bands below 1500 kHz, which arises from the interaction between various diffractions from the two gratings and Lamb modes in the brass plates immersed in water. The results indicate that the device has the advantages of multiple band, broader bandwidth, and simpler structure. Our finding should have great potential applications in ultrasonic devices

The asymmetric total synthesis of (+)- and (-)-trypargine via Noyori asymmetric transfer hydrogenation

International Nuclear Information System (INIS)

Pilli, Ronaldo A.; Rodrigues Junior, Manoel Trindade

2009-01-01

A concise and efficient total synthesis of (+)- and (-)-trypargine (6 steps and 38% overall yield), a 1-substituted β-carboline guanidine alkaloid isolated from the skin of the African frog K. senegalensis, was developed based on the construction of the b-carboline moiety via Bischler-Napieralski reaction and the enantioselective reduction of the dihydro-β-carboline intermediate via an asymmetric transfer hydrogenation reaction using Noyori's protocol. (author)

Stable walking with asymmetric legs

International Nuclear Information System (INIS)

Merker, Andreas; Rummel, Juergen; Seyfarth, Andre

2011-01-01

Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

Polarization dependent switching of asymmetric nanorings with a circular field

Directory of Open Access Journals (Sweden)

Nihar R. Pradhan

2016-01-01

Full Text Available We experimentally investigated the switching from onion to vortex states in asymmetric cobalt nanorings by an applied circular field. An in-plane field is applied along the symmetric or asymmetric axis of the ring to establish domain walls (DWs with symmetric or asymmetric polarization. A circular field is then applied to switch from the onion state to the vortex state, moving the DWs in the process. The asymmetry of the ring leads to different switching fields depending on the location of the DWs and direction of applied field. For polarization along the asymmetric axis, the field required to move the DWs to the narrow side of the ring is smaller than the field required to move the DWs to the larger side of the ring. For polarization along the symmetric axis, establishing one DW in the narrow side and one on the wide side, the field required to switch to the vortex state is an intermediate value.

[Combined orthodontic-orthoganthic surgery to treat asymmetric mandibular excess malocclusions].

Science.gov (United States)

Li, Xiao-Bing; Chen, Song; Chen, Yang-Xi; Li, Jun

2005-06-01

To discuss the skeletal and dentoalveolar characteristics of asymmetric mandibular excess malocclusions and to discuss the procedures of combined orthodontic-orthonganthic surgery treatments of asymmetric mandibular excess malocclusions. 25 cases treated by combined orthodontic-orthognathic surgery treatments were reviewed to find out the specialties of this kind of therapy. The asymmetric of mandible presents anterior and posterior teeth tipped both sagitally and horizontally, as well as upper and lower jaws incompatibility. The pre-surgical orthodontic treatments included decomposition of anterior and posterior teeth, leveling and aligning the teeth etc. The post-surgical orthodontic treatments were to detail the occlusions. The patients all got functional and aesthetic good results after the combined orthodontic-orthognathic surgery treatments. The asymmetric mandibular excess affects the harmony of the face badly, and the correction of it must be carried out by the combined orthodontic-orthognathic surgery treatments. The pre- and post-surgical orthodontic treatments are the key stages to make the skeletal corrections stable.

Opportunities in plant synthetic biology.

Science.gov (United States)

Cook, Charis; Martin, Lisa; Bastow, Ruth

2014-05-01

Synthetic biology is an emerging field uniting scientists from all disciplines with the aim of designing or re-designing biological processes. Initially, synthetic biology breakthroughs came from microbiology, chemistry, physics, computer science, materials science, mathematics, and engineering disciplines. A transition to multicellular systems is the next logical step for synthetic biologists and plants will provide an ideal platform for this new phase of research. This meeting report highlights some of the exciting plant synthetic biology projects, and tools and resources, presented and discussed at the 2013 GARNet workshop on plant synthetic biology.

High Current Ionic Diode Using Homogeneously Charged Asymmetric Nanochannel Network Membrane.

Science.gov (United States)

Choi, Eunpyo; Wang, Cong; Chang, Gyu Tae; Park, Jungyul

2016-04-13

A high current ionic diode is achieved using an asymmetric nanochannel network membrane (NCNM) constructed by soft lithography and in situ self-assembly of nanoparticles with uniform surface charge. The asymmetric NCNM exhibits high rectified currents without losing a rectification ratio because of its ionic selectivity gradient and differentiated electrical conductance. Asymmetric ionic transport is analyzed with diode-like I-V curves and visualized via fluorescent dyes, which is closely correlated with ionic selectivity and ion distribution according to variation of NCNM geometries.

From noise to synthetic nucleoli: can synthetic biology achieve new insights?

Science.gov (United States)

Ciechonska, Marta; Grob, Alice; Isalan, Mark

2016-04-18

Synthetic biology aims to re-organise and control biological components to make functional devices. Along the way, the iterative process of designing and testing gene circuits has the potential to yield many insights into the functioning of the underlying chassis of cells. Thus, synthetic biology is converging with disciplines such as systems biology and even classical cell biology, to give a new level of predictability to gene expression, cell metabolism and cellular signalling networks. This review gives an overview of the contributions that synthetic biology has made in understanding gene expression, in terms of cell heterogeneity (noise), the coupling of growth and energy usage to expression, and spatiotemporal considerations. We mainly compare progress in bacterial and mammalian systems, which have some of the most-developed engineering frameworks. Overall, one view of synthetic biology can be neatly summarised as "creating in order to understand."

Design of activated carbon/activated carbon asymmetric capacitors

Science.gov (United States)

Piñeiro-Prado, Isabel; Salinas-Torres, David; Ruiz Rosas, Ramiro; Morallon, Emilia; Cazorla-Amoros, Diego

2016-03-01

Supercapacitors are energy storage devices that offer a high power density and a low energy density in comparison with batteries. Their limited energy density can be overcome by using asymmetric configuration in mass electrodes, where each electrode works within their maximum available potential window, rendering the maximum voltage output of the system. Such asymmetric capacitors must be optimized through careful electrochemical characterization of the electrodes for accurate determination of the capacitance and the potential stability limits. The results of the characterization are then used for optimizing mass ratio of the electrodes from the balance of stored charge. The reliability of the design largely depends on the approach taken for the electrochemical characterization. Therefore, the performance could be lower than expected and even the system could break down, if a well thought out procedure is not followed. In this work, a procedure for the development of asymmetric supercapacitors based on activated carbons is detailed. Three activated carbon materials with different textural properties and surface chemistry have been systematically characterized in neutral aqueous electrolyte. The asymmetric configuration of the masses of both electrodes in the supercapacitor has allowed to cover a higher potential window, resulting in an increase of the energy density of the three devices studied when compared with the symmetric systems, and an improved cycle life.

Design of activated carbon/activated carbon asymmetric capacitors

Directory of Open Access Journals (Sweden)

Isabel ePiñeiro-Prado

2016-03-01

Full Text Available Supercapacitors are energy storage devices that offer a high power density and a low energy density in comparison with batteries. Their limited energy density can be overcome by using asymmetric configuration in mass electrodes, where each electrode works within their maximum available potential window, rendering the maximum voltage output of the system. Such asymmetric capacitors must be optimized through careful electrochemical characterization of the electrodes for accurate determination of the capacitance and the potential stability limits. The results of the characterization are then used for optimizing mass ratio of the electrodes from the balance of stored charge. The reliability of the design largely depends on the approach taken for the electrochemical characterization. Therefore, the performance could be lower than expected and even the system could break down, if a well thought out procedure is not followed.In this work, a procedure for the development of asymmetric supercapacitors based on activated carbons is detailed. Three activated carbon materials with different textural properties and surface chemistry have been systematically characterized in neutral aqueous electrolyte. The asymmetric configuration of the masses of both electrodes in the supercapacitor has allowed to cover a higher potential window, resulting in an increase of the energy density of the three devices studied when compared with the symmetric systems, and an improved cycle life.

Direct catalytic asymmetric aldol-Tishchenko reaction.

Science.gov (United States)

Gnanadesikan, Vijay; Horiuchi, Yoshihiro; Ohshima, Takashi; Shibasaki, Masakatsu

2004-06-30

A direct catalytic asymmetric aldol reaction of propionate equivalent was achieved via the aldol-Tishchenko reaction. Coupling an irreversible Tishchenko reaction to a reversible aldol reaction overcame the retro-aldol reaction problem and thereby afforded the products in high enantio and diastereoselectivity using 10 mol % of the asymmetric catalyst. A variety of ketones and aldehydes, including propyl and butyl ketones, were coupled efficiently, yielding the corresponding aldol-Tishchenko products in up to 96% yield and 95% ee. Diastereoselectivity was generally below the detection limit of 1H NMR (>98:2). Preliminary studies performed to clarify the mechanism revealed that the aldol products were racemic with no diastereoselectivity. On the other hand, the Tishchenko products were obtained in a highly enantiocontrolled manner.

Ion Motion Stability in Asymmetric Surface Electrode Ion Traps

Science.gov (United States)

Shaikh, Fayaz; Ozakin, Arkadas

2010-03-01

Many recently developed designs of the surface electrode ion traps for quantum information processing have asymmetry built into their geometries. The asymmetry helps rotate the trap axes to angles with respect to electrode surface that facilitate laser cooling of ions but introduces a relative angle between the RF and DC fields and invalidates the classical stability analysis of the symmetric case for which the equations of motion are decoupled. For asymmetric case the classical motion of a single ion is given by a coupled, multi-dimensional version of Mathieu's equation. In this poster we discuss the stability diagram of asymmetric surface traps by performing an approximate multiple scale perturbation analysis of the coupled Mathieu equations, and validate the results with numerical simulations. After obtaining the stability diagram for the linear fields, we simulate the motion of an ion in a given asymmetric surface trap, utilizing a method-of-moments calculation of the electrode fields. We obtain the stability diagram and compare it with the ideal case to find the region of validity. Finally, we compare the results of our stability analysis to experiments conducted on a microfabricated asymmetric surface trap.

Asymmetric information and list-price reductions in the housing market

NARCIS (Netherlands)

de Wit, E.; van der Klaauw, B.

2013-01-01

In housing markets with asymmetric information list prices may signal unobserved properties of the house or the seller. Asymmetric information is the starting point for many models for the housing market. In this paper, we estimate the causal effect of list-price reductions on the time houses remain

A living foundry for Synthetic Biological Materials: A synthetic biology roadmap to new advanced materials

Directory of Open Access Journals (Sweden)

Rosalind A. Le Feuvre

2018-06-01

Full Text Available Society is on the cusp of harnessing recent advances in synthetic biology to discover new bio-based products and routes to their affordable and sustainable manufacture. This is no more evident than in the discovery and manufacture of Synthetic Biological Materials, where synthetic biology has the capacity to usher in a new Materials from Biology era that will revolutionise the discovery and manufacture of innovative synthetic biological materials. These will encompass novel, smart, functionalised and hybrid materials for diverse applications whose discovery and routes to bio-production will be stimulated by the fusion of new technologies positioned across physical, digital and biological spheres. This article, which developed from an international workshop held in Manchester, United Kingdom, in 2017 [1], sets out to identify opportunities in the new materials from biology era. It considers requirements, early understanding and foresight of the challenges faced in delivering a Discovery to Manufacturing Pipeline for synthetic biological materials using synthetic biology approaches. This challenge spans the complete production cycle from intelligent and predictive design, fabrication, evaluation and production of synthetic biological materials to new ways of bringing these products to market. Pathway opportunities are identified that will help foster expertise sharing and infrastructure development to accelerate the delivery of a new generation of synthetic biological materials and the leveraging of existing investments in synthetic biology and advanced materials research to achieve this goal. Keywords: Synthetic biology, Materials, Biological materials, Biomaterials, Advanced materials

JET and COMPASS asymmetrical disruptions

Czech Academy of Sciences Publication Activity Database

Gerasimov, S.N.; Abreu, P.; Baruzzo, M.; Drozdov, V.; Dvornova, A.; Havlíček, Josef; Hender, T.C.; Hronová-Bilyková, Olena; Kruezi, U.; Li, X.; Markovič, Tomáš; Pánek, Radomír; Rubinacci, G.; Tsalas, M.; Ventre, S.; Villone, F.; Zakharov, L.E.

2015-01-01

Roč. 55, č. 11 (2015), s. 113006-113006 ISSN 0029-5515 R&D Projects: GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : tokamak * asymmetrical disruption * JET * COMPASS Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.040, year: 2015

Magnetically Modified Asymmetric Supercapacitors, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is for the development of an asymmetric supercapacitor that will have improved energy density and cycle life....

Synthetic biology and metabolic engineering.

Science.gov (United States)

Stephanopoulos, Gregory

2012-11-16

Metabolic engineering emerged 20 years ago as the discipline occupied with the directed modification of metabolic pathways for the microbial synthesis of various products. As such, it deals with the engineering (design, construction, and optimization) of native as well as non-natural routes of product synthesis, aided in this task by the availability of synthetic DNA, the core enabling technology of synthetic biology. The two fields, however, only partially overlap in their interest in pathway engineering. While fabrication of biobricks, synthetic cells, genetic circuits, and nonlinear cell dynamics, along with pathway engineering, have occupied researchers in the field of synthetic biology, the sum total of these areas does not constitute a coherent definition of synthetic biology with a distinct intellectual foundation and well-defined areas of application. This paper reviews the origins of the two fields and advances two distinct paradigms for each of them: that of unit operations for metabolic engineering and electronic circuits for synthetic biology. In this context, metabolic engineering is about engineering cell factories for the biological manufacturing of chemical and pharmaceutical products, whereas the main focus of synthetic biology is fundamental biological research facilitated by the use of synthetic DNA and genetic circuits.

Ideal MHD beta-limits of poloidally asymmetric equilibria

Energy Technology Data Exchange (ETDEWEB)

Todd, A.M.M.; Miller, A.E.; Grimm, R.C.; Okabayashi, M.; Dalhed, H.E. Jr.

1981-05-01

The ideal MHD stability of poloidally asymmetric equilibria, which are typical of a tokamak reactor design with a single-null poloidal divertor is examined. As with symmetric equilibria, stability to non-axisymmetric modes improves with increasing triangularity and ellipticity, and with lower edge safety factor. Pressure profiles optimized with respect to ballooning stability are obtained for an asymmetric shape, resulting in ..beta../sub critical/ approx. = 5.7%. The corresponding value for an equivalent symmetric shape is ..beta../sub critical/ approx. = 6.5%.

Ideal MHD beta-limits of poloidally asymmetric equilibria

International Nuclear Information System (INIS)

Todd, A.M.M.; Miller, A.E.; Grimm, R.C.; Okabayashi, M.; Dalhed, H.E. Jr.

1981-05-01

The ideal MHD stability of poloidally asymmetric equilibria, which are typical of a tokamak reactor design with a single-null poloidal divertor is examined. As with symmetric equilibria, stability to non-axisymmetric modes improves with increasing triangularity and ellipticity, and with lower edge safety factor. Pressure profiles optimized with respect to ballooning stability are obtained for an asymmetric shape, resulting in β/sub critical/ approx. = 5.7%. The corresponding value for an equivalent symmetric shape is β/sub critical/ approx. = 6.5%

Six transformer based asymmetrical embedded Z-source inverters

DEFF Research Database (Denmark)

Wei, Mo; Poh Chiang, Loh; Chi, Jin

2013-01-01

Embedded/Asymmetrical embedded Z-source inverters were proposed to maintain smooth input current/voltage across the dc source and within the impedance network, remain the shoot-through feature used to boost up the dc-link voltage without adding bulky filter at input side. This paper introduces a ...... a class of transformer based asymmetrical embedded Z-source inverters which keep the smooth input current and voltage while achieving enhanced voltage boost capability. The presented inverters are verified by laboratory prototypes experimentally....

Synthetic biological networks

International Nuclear Information System (INIS)

Archer, Eric; Süel, Gürol M

2013-01-01

Despite their obvious relationship and overlap, the field of physics is blessed with many insightful laws, while such laws are sadly absent in biology. Here we aim to discuss how the rise of a more recent field known as synthetic biology may allow us to more directly test hypotheses regarding the possible design principles of natural biological networks and systems. In particular, this review focuses on synthetic gene regulatory networks engineered to perform specific functions or exhibit particular dynamic behaviors. Advances in synthetic biology may set the stage to uncover the relationship of potential biological principles to those developed in physics. (review article)

Synchronised and complementary coordination mechanisms in an asymmetric joint aiming task

DEFF Research Database (Denmark)

Skewes, Joshua Charles; Skewes, Lea; Michael, John

2015-01-01

Many forms of social interaction require that behaviour be coordinated in the here and now. Much research has been conducted on how people coordinate their actions in real time to achieve a joint goal, showing that people use both synchronised (i.e. symmetric) and complementary (i.e. asymmetric) ...... in this asymmetric task, as people synchronise better with an irregular, but adaptive partner, than with a completely predictable, but non-responsive metronome. These results show that given asymmetric task constraints, adaptability, rather than predictability facilitates coordination....

Capability of DFIG WTS to ride through recurring asymmetrical grid faults

DEFF Research Database (Denmark)

Chen, Wenjie; Blaabjerg, Frede; Chen, Min

2014-01-01

The Wind Turbine Systems (WTS) are required to ride through recurring grid faults in some countries. In this paper, the capability of Doubly Fed Induction Generator (DFIG) WTS to ride through recurring asymmetrical grid faults is evaluated and compared with the ride through capability under single...... asymmetrical grid fault. A mathematical model of the DFIG under recurring asymmetrical grid faults is represented. The analysis are verified by simulations on a 1.5MW DFIG model and by experiments on a reduced-scale DFIG test system....

Influence of artificial tip perturbation on asymmetric vortices flow over a chined fuselage

Directory of Open Access Journals (Sweden)

Shi Wei

2015-08-01

Full Text Available An experimental study was conducted with the aim of understanding behavior of asymmetric vortices flow over a chined fuselage. The tests were carried out in a wind tunnel at Reynolds number of 1.87 × 105 under the conditions of high angles of attack and zero angle of sideslip. The results show that leeward vortices flow becomes asymmetric vortices flow when angle of attack increases over 20°. The asymmetric vortices flow is asymmetry of two forebody vortices owing to the increase of angle of attack but not asymmetry of vortex breakdown which appears when angle of attack is above 35°. Asymmetric vortices flow is sensitive to tip perturbation and is non-deterministic due to randomly distributed natural minute geometrical irregularities on the nose tip within machining tolerance. Deterministic asymmetric vortices flow can be obtained by attaching artificial tip perturbation which can trigger asymmetric vortices flow and decide asymmetric vortices flow pattern. Triggered by artificial tip perturbation, the vortex on the same side with perturbation is in a higher position, and the other vortex on the opposite side is in a lower position. Vortex suction on the lower vortex side is larger, which corresponds to a side force pointing to the lower vortex side.

Autorefraction versus subjective refraction in a radially asymmetric multifocal intraocular lens

NARCIS (Netherlands)

Linden, J.W.M. van der; Vrijman, V.; El-Saady, R.; Meulen, I.J. van der; Mourits, M.P.; Lapid-Gortzak, R.

2014-01-01

PURPOSE: To evaluate whether the automated refraction (AR) correlates with subjective manifest (MR) refraction in eyes implanted with radially asymmetric multifocal intraocular lens (IOLs). METHODS: This retrospective study evaluated 52 eyes (52 patients) implanted with a radially asymmetric

A living foundry for Synthetic Biological Materials: A synthetic biology roadmap to new advanced materials.

Science.gov (United States)

Le Feuvre, Rosalind A; Scrutton, Nigel S

2018-06-01

Society is on the cusp of harnessing recent advances in synthetic biology to discover new bio-based products and routes to their affordable and sustainable manufacture. This is no more evident than in the discovery and manufacture of Synthetic Biological Materials , where synthetic biology has the capacity to usher in a new Materials from Biology era that will revolutionise the discovery and manufacture of innovative synthetic biological materials. These will encompass novel, smart, functionalised and hybrid materials for diverse applications whose discovery and routes to bio-production will be stimulated by the fusion of new technologies positioned across physical, digital and biological spheres. This article, which developed from an international workshop held in Manchester, United Kingdom, in 2017 [1], sets out to identify opportunities in the new materials from biology era. It considers requirements, early understanding and foresight of the challenges faced in delivering a Discovery to Manufacturing Pipeline for synthetic biological materials using synthetic biology approaches. This challenge spans the complete production cycle from intelligent and predictive design, fabrication, evaluation and production of synthetic biological materials to new ways of bringing these products to market. Pathway opportunities are identified that will help foster expertise sharing and infrastructure development to accelerate the delivery of a new generation of synthetic biological materials and the leveraging of existing investments in synthetic biology and advanced materials research to achieve this goal.

Cell-free synthetic biology: thinking outside the cell.

Science.gov (United States)

Hodgman, C Eric; Jewett, Michael C

2012-05-01

Cell-free synthetic biology is emerging as a powerful approach aimed to understand, harness, and expand the capabilities of natural biological systems without using intact cells. Cell-free systems bypass cell walls and remove genetic regulation to enable direct access to the inner workings of the cell. The unprecedented level of control and freedom of design, relative to in vivo systems, has inspired the rapid development of engineering foundations for cell-free systems in recent years. These efforts have led to programmed circuits, spatially organized pathways, co-activated catalytic ensembles, rational optimization of synthetic multi-enzyme pathways, and linear scalability from the micro-liter to the 100-liter scale. It is now clear that cell-free systems offer a versatile test-bed for understanding why nature's designs work the way they do and also for enabling biosynthetic routes to novel chemicals, sustainable fuels, and new classes of tunable materials. While challenges remain, the emergence of cell-free systems is poised to open the way to novel products that until now have been impractical, if not impossible, to produce by other means. Copyright © 2011 Elsevier Inc. All rights reserved.

Electron Jet of Asymmetric Reconnection

Science.gov (United States)

Khotyaintsev, Yu. V.; Graham, D. B.; Norgren, C.; Eriksson, E.; Li, W.; Johlander, A.; Vaivads, A.; Andre, M.; Pritchett, P. L.; Retino, A.;

Field factors for asymmetric collimators

International Nuclear Information System (INIS)

Turner, J.R.; Butler, A.P.H.

1996-01-01

In recent years manufacturers have been supplying linear accelerators with either a single pair or a dual pair of collimators. The use of a model to relate off-axis field factors to on-axis field factors obviates the need for repeat measurements whenever the asymmetric collimators are employed. We have investigated the variation of collimator scatter Sc, with distance of the central ray x from the central axis for a variety of non square field sizes. Collimator scatter was measured by in-air measurements with a build-up cap. The Primaty-Off-Centre-Ratio (POCR) was measured in-air by scanning orthogonally across the beam with an ionization chamber. The result of the investigation is the useful prediction of off-axis field factors for a range of rectangular asymmetric fields using the simple product of the on-axis field factor and the POCR in air. The effect of asymmetry on the quality of the beam and hence the percent depth dose will be discussed. (author)

Cross-Layer Scheme to Control Contention Window for Per-Flow in Asymmetric Multi-Hop Networks

Science.gov (United States)

Giang, Pham Thanh; Nakagawa, Kenji

The IEEE 802.11 MAC standard for wireless ad hoc networks adopts Binary Exponential Back-off (BEB) mechanism to resolve bandwidth contention between stations. BEB mechanism controls the bandwidth allocation for each station by choosing a back-off value from one to CW according to the uniform random distribution, where CW is the contention window size. However, in asymmetric multi-hop networks, some stations are disadvantaged in opportunity of access to the shared channel and may suffer severe throughput degradation when the traffic load is large. Then, the network performance is degraded in terms of throughput and fairness. In this paper, we propose a new cross-layer scheme aiming to solve the per-flow unfairness problem and achieve good throughput performance in IEEE 802.11 multi-hop ad hoc networks. Our cross-layer scheme collects useful information from the physical, MAC and link layers of own station. This information is used to determine the optimal Contention Window (CW) size for per-station fairness. We also use this information to adjust CW size for each flow in the station in order to achieve per-flow fairness. Performance of our cross-layer scheme is examined on various asymmetric multi-hop network topologies by using Network Simulator (NS-2).

The effects of asymmetric directional microphone fittings on acceptance of background noise.

Science.gov (United States)

Kim, Jong S; Bryan, Melinda Freyaldenhoven

2011-05-01

The effects of asymmetric directional microphone fittings (i.e., an omnidirectional microphone on one ear and a directional microphone on the other) on speech understanding in noise and acceptance of background noise were investigated in 15 full-time hearing aid users. Subjects were fitted binaurally with four directional microphone conditions (i.e., binaural omnidirectional, right asymmetric directional, left asymmetric directional and binaural directional microphones) using Siemens Intuis Directional behind-the-ear hearing aids. Speech understanding in noise was assessed using the Hearing in Noise Test, and acceptance of background noise was assessed using the Acceptable Noise Level procedure. Speech was presented from 0° while noise was presented from 180° azimuth. The results revealed that speech understanding in noise improved when using asymmetric directional microphones compared to binaural omnidirectional microphone fittings and was not significantly hindered compared to binaural directional microphone fittings. The results also revealed that listeners accepted more background noise when fitted with asymmetric directional microphones as compared to binaural omnidirectional microphones. Lastly, the results revealed that the acceptance of noise was further increased for the binaural directional microphones when compared to the asymmetric directional microphones, maximizing listeners' willingness to accept background noise in the presence of noise. Clinical implications will be discussed.

Synthetic biology and occupational risk.

Science.gov (United States)

Howard, John; Murashov, Vladimir; Schulte, Paul

2017-03-01

Synthetic biology is an emerging interdisciplinary field of biotechnology that involves applying the principles of engineering and chemical design to biological systems. Biosafety professionals have done an excellent job in addressing research laboratory safety as synthetic biology and gene editing have emerged from the larger field of biotechnology. Despite these efforts, risks posed by synthetic biology are of increasing concern as research procedures scale up to industrial processes in the larger bioeconomy. A greater number and variety of workers will be exposed to commercial synthetic biology risks in the future, including risks to a variety of workers from the use of lentiviral vectors as gene transfer devices. There is a need to review and enhance current protection measures in the field of synthetic biology, whether in experimental laboratories where new advances are being researched, in health care settings where treatments using viral vectors as gene delivery systems are increasingly being used, or in the industrial bioeconomy. Enhanced worker protection measures should include increased injury and illness surveillance of the synthetic biology workforce; proactive risk assessment and management of synthetic biology products; research on the relative effectiveness of extrinsic and intrinsic biocontainment methods; specific safety guidance for synthetic biology industrial processes; determination of appropriate medical mitigation measures for lentiviral vector exposure incidents; and greater awareness and involvement in synthetic biology safety by the general occupational safety and health community as well as by government occupational safety and health research and regulatory agencies.

Synthetic Biology and Personalized Medicine

Science.gov (United States)

Jain, K.K.

2013-01-01

Synthetic biology, application of synthetic chemistry to biology, is a broad term that covers the engineering of biological systems with structures and functions not found in nature to process information, manipulate chemicals, produce energy, maintain cell environment and enhance human health. Synthetic biology devices contribute not only to improve our understanding of disease mechanisms, but also provide novel diagnostic tools. Methods based on synthetic biology enable the design of novel strategies for the treatment of cancer, immune diseases metabolic disorders and infectious diseases as well as the production of cheap drugs. The potential of synthetic genome, using an expanded genetic code that is designed for specific drug synthesis as well as delivery and activation of the drug in vivo by a pathological signal, was already pointed out during a lecture delivered at Kuwait University in 2005. Of two approaches to synthetic biology, top-down and bottom-up, the latter is more relevant to the development of personalized medicines as it provides more flexibility in constructing a partially synthetic cell from basic building blocks for a desired task. PMID:22907209

Beam-beam issues in asymmetric colliders

International Nuclear Information System (INIS)

Furman, M.A.

1992-07-01

We discuss generic beam-beam issues for proposed asymmetric e + - e - colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II)

Tracking the emergence of synthetic biology.

Science.gov (United States)

Shapira, Philip; Kwon, Seokbeom; Youtie, Jan

2017-01-01

Synthetic biology is an emerging domain that combines biological and engineering concepts and which has seen rapid growth in research, innovation, and policy interest in recent years. This paper contributes to efforts to delineate this emerging domain by presenting a newly constructed bibliometric definition of synthetic biology. Our approach is dimensioned from a core set of papers in synthetic biology, using procedures to obtain benchmark synthetic biology publication records, extract keywords from these benchmark records, and refine the keywords, supplemented with articles published in dedicated synthetic biology journals. We compare our search strategy with other recent bibliometric approaches to define synthetic biology, using a common source of publication data for the period from 2000 to 2015. The paper details the rapid growth and international spread of research in synthetic biology in recent years, demonstrates that diverse research disciplines are contributing to the multidisciplinary development of synthetic biology research, and visualizes this by profiling synthetic biology research on the map of science. We further show the roles of a relatively concentrated set of research sponsors in funding the growth and trajectories of synthetic biology. In addition to discussing these analyses, the paper notes limitations and suggests lines for further work.

Asymmetric synthesis including enzymatic catalysis of 11C and 13N labelled amino acids

International Nuclear Information System (INIS)

Langstrom, B.; Antonio, G.; Bjurling, P.; Fasth, K.J.; Westerberg, G.; Watanabe, Y.

1993-01-01

Use of asymmetric synthesis in production of 11 C- and 13 N-labelled amino acids has been shown to be a useful approach in order to prepare amino acids routinely for PET-studies. Such PET-studies are focused either on problems related to amino acid transport, protein synthesis rate or the turnover of neurotransmitters from amino acids. The paper discusses matters regarding synthetic strategies and techniques involving production of precursors, labelled intermediates and main reaction sequences. In synthesis using the short-lived β + -emitters like 11 C and 13 N with T 1/2 of 20.3 and 10.0 min respectively, many special aspects have to be considered. The use of enzymes as catalysts has shown to be a useful tool in such preparations. The design of the labelled amino acids especially considering the stereochemistry, the position of the label will be addressed since these points are important both with regard to the application of the labelled amino acids as well as to the synthesis itself. In this presentation of the synthesis of labelled amino acids these various aspects are discussed

Autorefraction versus subjective refraction in a radially asymmetric multifocal intraocular lens

NARCIS (Netherlands)

van der Linden, Jan Willem; Vrijman, Violette; Al-Saady, Rana; El-Saady, Rana; van der Meulen, Ivanka J.; Mourits, Maarten P.; Lapid-Gortzak, Ruth

2014-01-01

To evaluate whether the automated refraction (AR) correlates with subjective manifest (MR) refraction in eyes implanted with radially asymmetric multifocal intraocular lens (IOLs). This retrospective study evaluated 52 eyes (52 patients) implanted with a radially asymmetric multifocal IOL (LS-312

Printability of Synthetic Papers by Electrophotography

Directory of Open Access Journals (Sweden)

Rozália Szentgyörgyvölgyi

2010-04-01

Full Text Available This paper deals with the printability of synthetic papers by the electrophotography technique. Prints of cmyk colour fields from 20% to 100% raster tone values were printed on three types of synthetic papers (one film synthetic paper and two fiber synthetic papers. The investigation of the appearance included densitometric measurement of the cmyk prints. The results have shown differences in the optical density and optical tone value between cmyk prints made on various synthetic papers. The highest optical density and the increase of the optical tone value were observed on the film synthetic paper, where cmyk prints were more saturated. The highest abrasion resistance of cmyk prints was obtained from the fibre synthetic paper.

Smart-DS: Synthetic Models for Advanced, Realistic Testing: Distribution Systems and Scenarios

Energy Technology Data Exchange (ETDEWEB)

Krishnan, Venkat K [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Palmintier, Bryan S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hodge, Brian S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hale, Elaine T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Elgindy, Tarek [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bugbee, Bruce [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rossol, Michael N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lopez, Anthony J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Krishnamurthy, Dheepak [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Vergara, Claudio [MIT; Domingo, Carlos Mateo [IIT Comillas; Postigo, Fernando [IIT Comillas; de Cuadra, Fernando [IIT Comillas; Gomez, Tomas [IIT Comillas; Duenas, Pablo [MIT; Luke, Max [MIT; Li, Vivian [MIT; Vinoth, Mohan [GE Grid Solutions; Kadankodu, Sree [GE Grid Solutions

2017-08-09

The National Renewable Energy Laboratory (NREL) in collaboration with Massachusetts Institute of Technology (MIT), Universidad Pontificia Comillas (Comillas-IIT, Spain) and GE Grid Solutions, is working on an ARPA-E GRID DATA project, titled Smart-DS, to create: 1) High-quality, realistic, synthetic distribution network models, and 2) Advanced tools for automated scenario generation based on high-resolution weather data and generation growth projections. Through these advancements, the Smart-DS project is envisioned to accelerate the development, testing, and adoption of advanced algorithms, approaches, and technologies for sustainable and resilient electric power systems, especially in the realm of U.S. distribution systems. This talk will present the goals and overall approach of the Smart-DS project, including the process of creating the synthetic distribution datasets using reference network model (RNM) and the comprehensive validation process to ensure network realism, feasibility, and applicability to advanced use cases. The talk will provide demonstrations of early versions of synthetic models, along with the lessons learnt from expert engagements to enhance future iterations. Finally, the scenario generation framework, its development plans, and co-ordination with GRID DATA repository teams to house these datasets for public access will also be discussed.

The asymmetric rotator model applied to odd-mass iridium isotopes

International Nuclear Information System (INIS)

Piepenbring, R.

1980-04-01

The method of inversion of the eigenvalue problem previously developed for nuclei with axial symmetry is extended to asymmetric equilibrium shapes. This new approach of the asymmetric rotator model is applied to the odd-mass iridium isotopes. A satisfactory and coherent description of the observed energy spectra is obtained, especially for the lighter isotopes

All Pseudocapacitive MXene-RuO2 Asymmetric Supercapacitors

KAUST Repository

Jiang, Qiu

2018-01-23

2D transition metal carbides and nitrides, known as MXenes, are an emerging class of 2D materials with a wide spectrum of potential applications, in particular in electrochemical energy storage. The hydrophilicity of MXenes combined with their metallic conductivity and surface redox reactions is the key for high-rate pseudocapacitive energy storage in MXene electrodes. However, symmetric MXene supercapacitors have a limited voltage window of around 0.6 V due to possible oxidation at high anodic potentials. In this study, the fact that titanium carbide MXene (Ti3C2Tx) can operate at negative potentials in acidic electrolyte is exploited, to design an all-pseudocapacitive asymmetric device by combining it with a ruthenium oxide (RuO2) positive electrode. This asymmetric device operates at a voltage window of 1.5 V, which is about two times wider than the operating voltage window of symmetric MXene supercapacitors, and is the widest voltage window reported to date for MXene-based supercapacitors. The complementary working potential windows of MXene and RuO2, along with proton-induced pseudocapacitance, significantly enhance the device performance. As a result, the asymmetric devices can deliver an energy density of 37 µW h cm−2 at a power density of 40 mW cm−2, with 86% capacitance retention after 20 000 charge–discharge cycles. These results show that pseudocapacitive negative MXene electrodes can potentially replace carbon-based materials in asymmetric electrochemical capacitors, leading to an increased energy density.

Determination and identification of synthetic cannabinoids and their metabolites in different matrices by modern analytical techniques – a review

International Nuclear Information System (INIS)

Znaleziona, Joanna; Ginterová, Pavlína; Petr, Jan; Ondra, Peter; Válka, Ivo; Ševčík, Juraj; Chrastina, Jan; Maier, Vítězslav

2015-01-01

Highlights: • Synthetic cannabinoids from analytical point of view. • Determination and identification methods of synthetic cannabinoids in different matrices. • Analytical techniques used from thin layer chromatography to high resolution mass spectrometry. • Detailed survey of gas and liquid chromatography methods for synthetic cannabinoids analysis. - Abstract: Synthetic cannabinoids have gained popularity due to their easy accessibility and psychoactive effects. Furthermore, they cannot be detected in urine by routine drug monitoring. The wide range of active ingredients in analyzed matrices hinders the development of a standard analytical method for their determination. Moreover, their possible side effects are not well known which increases the danger. This review is focused on the sample preparation and the determination of synthetic cannabinoids in different matrices (serum, urine, herbal blends, oral fluid, hair) published since 2004. The review includes separation and identification techniques, such as thin layer chromatography, gas and liquid chromatography and capillary electrophoresis, mostly coupled with mass spectrometry. The review also includes results by spectral methods like infrared spectroscopy, nuclear magnetic resonance or direct-injection mass spectrometry

Determination and identification of synthetic cannabinoids and their metabolites in different matrices by modern analytical techniques – a review

Energy Technology Data Exchange (ETDEWEB)

Znaleziona, Joanna; Ginterová, Pavlína; Petr, Jan [Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, Olomouc CZ-77146 (Czech Republic); Ondra, Peter; Válka, Ivo [Department of Forensic Medicine and Medical Law Faculty Hospital, Hněvotínská 3, Olomouc CZ-77146 (Czech Republic); Ševčík, Juraj [Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, Olomouc CZ-77146 (Czech Republic); Chrastina, Jan [Institute of Special Education Studies, Faculty of Education, Palacký University, Žižkovo náměsti 5, Olomouc CZ-77146 (Czech Republic); Maier, Vítězslav, E-mail: vitezslav.maier@upol.cz [Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, Olomouc CZ-77146 (Czech Republic)

2015-05-18

Highlights: • Synthetic cannabinoids from analytical point of view. • Determination and identification methods of synthetic cannabinoids in different matrices. • Analytical techniques used from thin layer chromatography to high resolution mass spectrometry. • Detailed survey of gas and liquid chromatography methods for synthetic cannabinoids analysis. - Abstract: Synthetic cannabinoids have gained popularity due to their easy accessibility and psychoactive effects. Furthermore, they cannot be detected in urine by routine drug monitoring. The wide range of active ingredients in analyzed matrices hinders the development of a standard analytical method for their determination. Moreover, their possible side effects are not well known which increases the danger. This review is focused on the sample preparation and the determination of synthetic cannabinoids in different matrices (serum, urine, herbal blends, oral fluid, hair) published since 2004. The review includes separation and identification techniques, such as thin layer chromatography, gas and liquid chromatography and capillary electrophoresis, mostly coupled with mass spectrometry. The review also includes results by spectral methods like infrared spectroscopy, nuclear magnetic resonance or direct-injection mass spectrometry.

Asymmetric Facial Bone Fragmentation Mirrors Asymmetric Distribution of Cranial Neuromasts in Blind Mexican Cavefish

Directory of Open Access Journals (Sweden)

Joshua B. Gross

2016-10-01

Full Text Available Craniofacial asymmetry is a convergent trait widely distributed across animals that colonize the extreme cave environment. Although craniofacial asymmetry can be discerned easily, other complex phenotypes (such as sensory organ position and numerical variation are challenging to score and compare. Certain bones of the craniofacial complex demonstrate substantial asymmetry, and co-localize to regions harboring dramatically expanded numbers of mechanosensory neuromasts. To determine if a relationship exists between this expansion and bone fragmentation in cavefish, we developed a quantitative measure of positional symmetry across the left-right axis. We found that three different cave-dwelling populations were significantly more asymmetric compared to surface-dwelling fish. Moreover, cave populations did not differ in the degree of neuromast asymmetry. This work establishes a method for quantifying symmetry of a complex phenotype, and demonstrates that facial bone fragmentation mirrors the asymmetric distribution of neuromasts in different cavefish populations. Further developmental studies will provide a clearer picture of the developmental and cellular changes that accompany this extreme phenotype, and help illuminate the genetic basis for facial asymmetry in vertebrates.

Impact of asymmetric lamp positioning on the performance of a closed-conduit UV reactor

Directory of Open Access Journals (Sweden)

Tipu Sultan

2017-06-01

Full Text Available Computational fluid dynamics (CFD analyses for the performance improvement of a closed-conduit ultraviolet (UV reactor were performed by changing the lamp positions from symmetric to asymmetric. The asymmetric lamp positioning can be useful for UV reactor design and optimization. This goal was achieved by incorporating the two performance factors, namely reduction equivalent dose (RED and system dose performance. Four cases were carried out for asymmetric lamp positioning within the UV reactor chamber and each case consisted of four UV lamps that were simulated once symmetrically and four times asymmetrically. The results of the four asymmetric cases were compared with the symmetric one. Moreover, these results were evaluated by using CFD simulations of a closed-conduit UV reactor. The fluence rate model, UVCalc3D was employed to validate the simulations results. The simulation results provide detailed information about the dose distribution, pathogen track modeling and RED. The RED value was increased by approximately 15% by using UVCalc3D fluence rate model. Additionally, the asymmetric lamp positioning of the UV lamps had more than 50% of the pathogens received a better and a higher UV dose than in the symmetric case. Consequently, the system dose performance was improved by asymmetric lamp positioning. It was concluded that the performance parameters (higher RED and system dose performance were improved by using asymmetric lamp positioning.

Evolvable synthetic neural system

Science.gov (United States)

Curtis, Steven A. (Inventor)

2009-01-01

An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

Electron Raman scattering in asymmetrical multiple quantum wells

International Nuclear Information System (INIS)

Betancourt-Riera, R; Rosas, R; Marin-Enriquez, I; Riera, R; Marin, J L

2005-01-01

Optical properties of asymmetrical multiple quantum wells for the construction of quantum cascade lasers are calculated, and expressions for the electronic states of asymmetrical multiple quantum wells are presented. The gain and differential cross-section for an electron Raman scattering process are obtained. Also, the emission spectra for several scattering configurations are discussed, and the corresponding selection rules for the processes involved are studied; an interpretation of the singularities found in the spectra is given. The electron Raman scattering studied here can be used to provide direct information about the efficiency of the lasers

Preview-based Asymmetric Load Reduction of Wind Turbines

DEFF Research Database (Denmark)

Madsen, Mathias; Filsø, Jakob; Soltani, Mohsen

2012-01-01

Controller (MPC) developed is based on a model with individual blade pitching to utilize the LIDAR measurements. The MPC must also maintain a given power reference while satisfying a set of actuator constraints. The designed controller was tested on a 5 MW wind turbine in the FAST simulator and compared......Fatigue loads on wind turbines caused by an asymmetric wind field become an increasing concern when the scale of wind turbines increases. This paper presents a model based predictive approach to reduce asymmetric loads by using Light Detection And Ranging (LIDAR) measurements. The Model Predictive...

Laughlin-like States in Bosonic and Fermionic Atomic Synthetic Ladders

Directory of Open Access Journals (Sweden)

Marcello Calvanese Strinati

2017-06-01

Full Text Available The combination of interactions and static gauge fields plays a pivotal role in our understanding of strongly correlated quantum matter. Cold atomic gases endowed with a synthetic dimension are emerging as an ideal platform to experimentally address this interplay in quasi-one-dimensional systems. A fundamental question is whether these setups can give access to pristine two-dimensional phenomena, such as the fractional quantum Hall effect, and how. We show that unambiguous signatures of bosonic and fermionic Laughlin-like states can be observed and characterized in synthetic ladders. We theoretically diagnose these Laughlin-like states focusing on the chiral current flowing in the ladder, on the central charge of the low-energy theory, and on the properties of the entanglement entropy. Remarkably, Laughlin-like states are separated from conventional liquids by Lifschitz-type transitions, characterized by sharp discontinuities in the current profiles, which we address using extensive simulations based on matrix-product states. Our work provides a qualitative and quantitative guideline towards the observability and understanding of strongly correlated states of matter in synthetic ladders. In particular, we unveil how state-of-the-art experimental settings constitute an ideal starting point to progressively tackle two-dimensional strongly interacting systems from a ladder viewpoint, opening a new perspective for the observation of non-Abelian states of matter.

Prospects of asymmetrically H-terminated zigzag germanene nanoribbons for spintronic application

Energy Technology Data Exchange (ETDEWEB)

Sharma, Varun, E-mail: varun@iiitm.ac.in [Nanomaterials Research Group, ABV-Indian Institute of Information Technology and Management (IIITM), Gwalior 474015 (India); Srivastava, Pankaj [Nanomaterials Research Group, ABV-Indian Institute of Information Technology and Management (IIITM), Gwalior 474015 (India); Jaiswal, Neeraj K. [Discipline of Physics, Indian Institute of Information Technology, Design & Manufacturing, Jabalpur, Dumna Airport Road, Jabalpur 482005 (India)

2017-02-28

Highlights: • Asymmetric hydrogen termination of Zigzag Germanene Nanoribbons (ZGeNR) is presented with their plausible spintronic device application. • It is revealed that asymmetric terminations are energetically more favourable compared to symmetric terminations. • The magnetic moment analysis depicts that asymmetric ZGeNR have a magnetic ground state with a preferred ferromagnetic (FM) coupling. • Presented doped asymmetric ZGeNR exhibits a half-metallic character which makes them qualify for spin-filtering device. - Abstract: First-principles investigations have been performed to explore the spin based electronic and transport properties of asymmetrically H-terminated zigzag germanene nanoribbons (2H−H ZGeNR). Investigations reveal a significant formation energy difference (ΔE{sub F} = E{sub F(2H-H)} − E{sub F(H-H)} ∼ −0.49 eV), highlighting more energetic stability for asymmetric edge termination compared to symmetric edge termination, irrespective of the ribbon width. Further, magnetic moment analysis and total energy calculations were performed to unveil that these structures have a magnetic ground state with preferred ferromagnetic (FM) coupling. The calculated E-k structures project a unique bipolar semiconducting behaviour for 2H−H ZGeNR which is contrast to H-terminated ZGeNR. Half-metallic transformation has also been revealed via suitable p-type or n-type doping for these structures. Finally, transport calculations were performed to highlight the selective contributions of spin-down (spin-up) electrons in the I–V characteristics of the doped 2H−H ZGeNR, suggesting their vitality for spintronic device applications.

The Respiratory Impedance in an Asymmetric Model of the Lung Structure

Directory of Open Access Journals (Sweden)

Robin De Keyser

2011-01-01

Full Text Available This paper presents a model of the respiratory tree as a recurrent, but asymmetric, structure. The intrinsic properties posed by such a system lead to a multi-fractal structure, i.e. a non-integer order model of the total impedance. The fractional order behavior of the asymmetric tree simulated as a dynamic system is assessed by means of Bode plots, on a wide range of frequencies. The results indicate than in a specific frequency range, both the symmetric
and asymmetric representation of the respiratory tree lead to similar values in the impedance.

Process for fabricating PBI hollow fiber asymmetric membranes for gas separation and liquid separation

Science.gov (United States)

Jayaweera, Indira; Krishnan, Gopala N.; Sanjurjo, Angel; Jayaweera, Palitha; Bhamidi, Srinivas

2016-04-26

The invention provides methods for preparing an asymmetric hollow fiber, the asymmetric hollow fibers prepared by such methods, and uses of the asymmetric hollow fibers. One method involves passing a polymeric solution through an outer annular orifice of a tube-in-orifice spinneret, passing a bore fluid though an inner tube of the spinneret, dropping the polymeric solution and bore fluid through an atmosphere over a dropping distance, and quenching the polymeric solution and bore fluid in a bath to form an asymmetric hollow fiber.

Synthetic Cathinones ("Bath Salts")

Science.gov (United States)

... Alcohol Club Drugs Cocaine Fentanyl Hallucinogens Inhalants Heroin Marijuana MDMA (Ecstasy/Molly) Methamphetamine Opioids Over-the-Counter Medicines Prescription Medicines Steroids (Anabolic) Synthetic Cannabinoids (K2/Spice) Synthetic Cathinones (Bath Salts) Tobacco/ ...

Bianisotropic metamaterials based on twisted asymmetric crosses

International Nuclear Information System (INIS)

Reyes-Avendaño, J A; Sampedro, M P; Juárez-Ruiz, E; Pérez-Rodríguez, F

2014-01-01

The effective bianisotropic response of 3D periodic metal-dielectric structures, composed of crosses with asymmetrically-cut wires, is investigated within a general homogenization theory using the Fourier formalism and the form-factor division approach. It is found that the frequency dependence of the effective permittivity for a system of periodically-repeated layers of metal crosses exhibits two strong resonances, whose separation is due to the cross asymmetry. Besides, bianisotropic metamaterials, having a base of four twisted asymmetric crosses, are proposed. The designed metamaterials possess negative refractive index at frequencies determined by the cross asymmetry, the gap between the arms of adjacent crosses lying on the same plane, and the type of Bravais lattice. (papers)

Chemoselective Switch in the Asymmetric Organocatalysis of 5 H -Oxazol-4-ones and N -Itaconimides: Addition-Protonation or [4+2] Cycloaddition

KAUST Repository

Zhu, Bo

2015-12-09

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. We report a synthetic strategy for a chemoselective switch and a diastereo-divergent approach for the asymmetric reaction of 5H-oxazol-4-ones and N-itaconimides catalyzed by L-tert-leucine-derived tertiary amine-urea compounds. The reaction was modulated to harness either tandem conjugate addition-protonation or [4+2] cycloaddition as major product with excellent enantio- and diastereoselectivities. Subjecting the enantio-enriched cycloaddition products to a basic silica gel reagent yields the diastereomer vis-à-vis the product directly obtained under conditions for addition-protonation, thus opening a diastereo-divergent route for creating 1,3-tertiary-hetero-quaternary stereocenters. Quantum chemical studies further provide stereochemical analysis for the [4+2] process and a plausible mechanism for this chemoselective switch is proposed.

Asymmetric Distribution of GFAP in Glioma Multipotent Cells

Science.gov (United States)

Guichet, Pierre-Olivier; Guelfi, Sophie; Ripoll, Chantal; Teigell, Marisa; Sabourin, Jean-Charles; Bauchet, Luc; Rigau, Valérie; Rothhut, Bernard; Hugnot, Jean-Philippe

2016-01-01

Asymmetric division (AD) is a fundamental mechanism whereby unequal inheritance of various cellular compounds during mitosis generates unequal fate in the two daughter cells. Unequal repartitions of transcription factors, receptors as well as mRNA have been abundantly described in AD. In contrast, the involvement of intermediate filaments in this process is still largely unknown. AD occurs in stem cells during development but was also recently observed in cancer stem cells. Here, we demonstrate the asymmetric distribution of the main astrocytic intermediate filament, namely the glial fibrillary acid protein (GFAP), in mitotic glioma multipotent cells isolated from glioblastoma (GBM), the most frequent type of brain tumor. Unequal mitotic repartition of GFAP was also observed in mice non-tumoral neural stem cells indicating that this process occurs across species and is not restricted to cancerous cells. Immunofluorescence and videomicroscopy were used to capture these rare and transient events. Considering the role of intermediate filaments in cytoplasm organization and cell signaling, we propose that asymmetric distribution of GFAP could possibly participate in the regulation of normal and cancerous neural stem cell fate. PMID:26953813

Asymmetric Distribution of GFAP in Glioma Multipotent Cells.

Directory of Open Access Journals (Sweden)

Pierre-Olivier Guichet

Full Text Available Asymmetric division (AD is a fundamental mechanism whereby unequal inheritance of various cellular compounds during mitosis generates unequal fate in the two daughter cells. Unequal repartitions of transcription factors, receptors as well as mRNA have been abundantly described in AD. In contrast, the involvement of intermediate filaments in this process is still largely unknown. AD occurs in stem cells during development but was also recently observed in cancer stem cells. Here, we demonstrate the asymmetric distribution of the main astrocytic intermediate filament, namely the glial fibrillary acid protein (GFAP, in mitotic glioma multipotent cells isolated from glioblastoma (GBM, the most frequent type of brain tumor. Unequal mitotic repartition of GFAP was also observed in mice non-tumoral neural stem cells indicating that this process occurs across species and is not restricted to cancerous cells. Immunofluorescence and videomicroscopy were used to capture these rare and transient events. Considering the role of intermediate filaments in cytoplasm organization and cell signaling, we propose that asymmetric distribution of GFAP could possibly participate in the regulation of normal and cancerous neural stem cell fate.

Origin of Asymmetric Charge Partitioning in the Dissociation of Gas-Phase Protein Homodimers

OpenAIRE

Jurchen, John C.; Williams, Evan R.

2003-01-01

The origin of asymmetric charge and mass partitioning observed for gas-phase dissociation of multiply charged macromolecular complexes has been hotly debated. These experiments hold the potential to provide detailed information about the interactions between the macromolecules within the complex. Here, this unusual phenomenon of asymmetric charge partitioning is investigated for several protein homodimers. Asymmetric charge partitioning in these ions depends on a number of factors, including ...

In situ biomolecule production by bacteria; a synthetic biology approach to medicine.

Science.gov (United States)

Flores Bueso, Yensi; Lehouritis, Panos; Tangney, Mark

2018-04-10

The ability to modify existing microbiota at different sites presents enormous potential for local or indirect management of various diseases. Because bacteria can be maintained for lengthy periods in various regions of the body, they represent a platform with enormous potential for targeted production of biomolecules, which offer tremendous promise for therapeutic and diagnostic approaches for various diseases. While biological medicines are currently limited in the clinic to patient administration of exogenously produced biomolecules from engineered cells, in situ production of biomolecules presents enormous scope in medicine and beyond. The slow pace and high expense of traditional research approaches has particularly hampered the development of biological medicines. It may be argued that bacterial-based medicine has been "waiting" for the advent of enabling technology. We propose that this technology is Synthetic Biology, and that the wait is over. Synthetic Biology facilitates a systematic approach to programming living entities and/or their products, using an approach to Research and Development (R&D) that facilitates rapid, cheap, accessible, yet sophisticated product development. Full engagement with the Synthetic Biology approach to R&D can unlock the potential for bacteria as medicines for cancer and other indications. In this review, we describe how by employing Synthetic Biology, designer bugs can be used as drugs, drug-production factories or diagnostic devices, using oncology as an exemplar for the concept of in situ biomolecule production in medicine. Copyright © 2018 Elsevier B.V. All rights reserved.

Asymmetric cell division of stem cells in the lung and other systems

Directory of Open Access Journals (Sweden)

Mohamed eBerika

2014-07-01

Full Text Available New insights have been added to identification, behavior and cellular properties of embryonic and tissue-specific stem cells over the last few years. The modes of stem cell division, asymmetric versus symmetric, are tightly regulated during development and regeneration. The proper choice of a stem cell to divide asymmetrically or symmetrically has great consequences for development and disease because inappropriate asymmetric division disrupts organ morphogenesis, whereas uncontrolled symmetric division induces tumorigenesis. Therefore, understanding the behavior of lung stem cells could identify innovative solutions for restoring normal morphogenesis and/or regeneration of different organs. In this concise review, we describe recent studies in our laboratory about the mode of division of lung epithelial stem cells. We also compare asymmetric cell division in the lung stem cells with other tissues in different organisms.

Asymmetric Aminalization via Cation-Binding Catalysis

DEFF Research Database (Denmark)

Park, Sang Yeon; Liu, Yidong; Oh, Joong Suk

2018-01-01

Asymmetric cation-binding catalysis, in principle, can generate "chiral" anionic nucleophiles, where the counter cations are coordinated within chiral environments. Nitrogen-nucleophiles are intrinsically basic, therefore, its use as nucleophiles is often challenging and limiting the scope of the...

Molecular Imaging in Synthetic Biology, and Synthetic Biology in Molecular Imaging.

Science.gov (United States)

Gilad, Assaf A; Shapiro, Mikhail G

2017-06-01

Biomedical synthetic biology is an emerging field in which cells are engineered at the genetic level to carry out novel functions with relevance to biomedical and industrial applications. This approach promises new treatments, imaging tools, and diagnostics for diseases ranging from gastrointestinal inflammatory syndromes to cancer, diabetes, and neurodegeneration. As these cellular technologies undergo pre-clinical and clinical development, it is becoming essential to monitor their location and function in vivo, necessitating appropriate molecular imaging strategies, and therefore, we have created an interest group within the World Molecular Imaging Society focusing on synthetic biology and reporter gene technologies. Here, we highlight recent advances in biomedical synthetic biology, including bacterial therapy, immunotherapy, and regenerative medicine. We then discuss emerging molecular imaging approaches to facilitate in vivo applications, focusing on reporter genes for noninvasive modalities such as magnetic resonance, ultrasound, photoacoustic imaging, bioluminescence, and radionuclear imaging. Because reporter genes can be incorporated directly into engineered genetic circuits, they are particularly well suited to imaging synthetic biological constructs, and developing them provides opportunities for creative molecular and genetic engineering.

New designer drugs (synthetic cannabinoids and synthetic cathinones): review of literature.

Science.gov (United States)

Cottencin, Olivier; Rolland, Benjamin; Karila, Laurent

2014-01-01

New designer drugs (synthetic cannabinoids and synthetic cathinones) are new "legal highs" that are sold online for recreational public or private use. Synthetic cannabinoids are psychoactive herbal and chemical products that mimic the effects of cannabis when used. These drugs are available on the Internet or in head shops as incense or air fresheners to circumvent the law. Cathinone is a naturally occurring beta-ketone amphetamine analog found in the leaves of the Catha edulis plant. Synthetic cathinones are phenylalkylamine derivatives that may possess amphetamine-like properties. These drugs are sold online as bath salts. Designer drugs are often labeled as "not for human consumption" to circumvent drug abuse legislation. The absence of legal risks, the ease of obtaining these drugs, the moderate cost, and the availability via the Internet are the main features that attract users, but the number of intoxicated people presenting with emergencies is increasing. There is evidence that negative health and social consequences may affect recreational and chronic users. The addictive potential of designer drugs is not negligible.

Uniform versus asymmetric shading mediates crown recession in conifers.

Directory of Open Access Journals (Sweden)

Amanda L Schoonmaker

Full Text Available In this study we explore the impact of asymmetrical vs. uniform crown shading on the mortality and growth of upper and lower branches within tree crowns, for two conifer species: shade intolerant lodgepole pine (Pinus contorta and shade tolerant white spruce (Picea glauca. We also explore xylem hydraulics, foliar nutrition, and carbohydrate status as drivers for growth and expansion of the lower and upper branches in various types of shading. This study was conducted over a two-year period across 10 regenerating forest sites dominated by lodgepole pine and white spruce, in the lower foothills of Alberta, Canada. Trees were assigned to one of four shading treatments: (1, complete uniform shading of the entire tree, (2 light asymmetric shading where the lower 1/4-1/3 of the tree crown was shaded, (3 heavy asymmetric shading as in (2 except with greater light reduction and (4 control in which no artificial shading occurred and most of the entire crown was exposed to full light. Asymmetrical shading of only the lower crown had a larger negative impact on the bud expansion and growth than did uniform shading, and the effect was stronger in pine relative to spruce. In addition, lower branches in pine also had lower carbon reserves, and reduced xylem-area specific conductivity compared to spruce. For both species, but particularly the pine, the needles of lower branches tended to store less C than upper branches in the asymmetric shade, which could suggest a movement of reserves away from the lower branches. The implications of these findings correspond with the inherent shade tolerance and self-pruning behavior of these conifers and supports a carbon based mechanism for branch mortality--mediated by an asymmetry in light exposure of the crown.

Current status of synthetic epikeratoplasty.

Science.gov (United States)

Thompson, K P; Hanna, K; Waring, G O; Gipson, I; Liu, Y; Gailitis, R P; Johnson-Wint, B; Green, K

1991-01-01

Many of the deficiencies with human tissue epikeratoplasty might be improved by the use of a suitable synthetic lenticule. Potential biomaterials for epikeratoplasty include collagen (types I, III, or IV), collagen-hydrogel copolymers, bioactive synthetics, and coated hydrogels. The biomaterial must be engineered to achieve strict specifications of optical clarity, support of epithelial migration and adhesion, permeability to solutes, and stability to corneal proteases. Attaching synthetic lenticules to the cornea without cutting Bowman's layer by adhesives, laser welding, or direct adhesion may also improve the efficacy of synthetic epikeratoplasty.

Tissue Harmonic Synthetic Aperture Imaging

DEFF Research Database (Denmark)

Rasmussen, Joachim

The main purpose of this PhD project is to develop an ultrasonic method for tissue harmonic synthetic aperture imaging. The motivation is to advance the field of synthetic aperture imaging in ultrasound, which has shown great potentials in the clinic. Suggestions for synthetic aperture tissue...... system complexity compared to conventional synthetic aperture techniques. In this project, SASB is sought combined with a pulse inversion technique for 2nd harmonic tissue harmonic imaging. The advantages in tissue harmonic imaging (THI) are expected to further improve the image quality of SASB...

Life after the synthetic cell

DEFF Research Database (Denmark)

Rasmussen, Steen

2010-01-01

Nature asked eight synthetic-biology experts about the implications for science and society of the “synthetic cell” made by the J. Craig Venter Institute (JCVI). The institute's team assembled, modified and implanted a synthesized genome into a DNA-free bacterial shell to make a self-replicating ......Nature asked eight synthetic-biology experts about the implications for science and society of the “synthetic cell” made by the J. Craig Venter Institute (JCVI). The institute's team assembled, modified and implanted a synthesized genome into a DNA-free bacterial shell to make a self...

Diradical character dependences of the first and second hyperpolarizabilities of asymmetric open-shell singlet systems.

Science.gov (United States)

Nakano, Masayoshi; Champagne, Benoît

2013-06-28

The static first and second hyperpolarizabilities (referred to as β and γ, respectively) of asymmetric open-shell singlet systems have been investigated using the asymmetric two-site diradical model within the valence configuration interaction level of theory in order to reveal the effect of the asymmetric electron distribution on the diradical character and subsequently on β and γ. It is found that the increase of the asymmetric electron distribution causes remarkable changes in the amplitude and the sign of β and γ, and that their variations are intensified with the increase of the diradical character. These results demonstrate that the asymmetric open-shell singlet systems with intermediate diradical characters can exhibit further enhancements of β and γ as compared to conventional asymmetric closed-shell systems and also to symmetric open-shell singlet systems with intermediate diradical characters.

An efficient catalyst for asymmetric Reformatsky reaction

Indian Academy of Sciences (India)

rate enantioselectivity using N,N-dialkylnorephedrines as chiral ligands. ..... temperatures also, there was no product conversion. ... Optimization of reaction conditions for asymmetric Reformatsky reaction between benzaldehyde and α-.

LG tools for asymmetric wargaming

Science.gov (United States)

Stilman, Boris; Yakhnis, Alex; Yakhnis, Vladimir

2002-07-01

Asymmetric operations represent conflict where one of the sides would apply military power to influence the political and civil environment, to facilitate diplomacy, and to interrupt specified illegal activities. This is a special type of conflict where the participants do not initiate full-scale war. Instead, the sides may be engaged in a limited open conflict or one or several sides may covertly engage another side using unconventional or less conventional methods of engagement. They may include peace operations, combating terrorism, counterdrug operations, arms control, support of insurgencies or counterinsurgencies, show of force. An asymmetric conflict can be represented as several concurrent interlinked games of various kinds: military, transportation, economic, political, etc. Thus, various actions of peace violators, terrorists, drug traffickers, etc., can be expressed via moves in different interlinked games. LG tools allow us to fully capture the specificity of asymmetric conflicts employing the major LG concept of hypergame. Hypergame allows modeling concurrent interlinked processes taking place in geographically remote locations at different levels of resolution and time scale. For example, it allows us to model an antiterrorist operation taking place simultaneously in a number of countries around the globe and involving wide range of entities from individuals to combat units to governments. Additionally, LG allows us to model all sides of the conflict at their level of sophistication. Intelligent stakeholders are represented by means of LG generated intelligent strategies. TO generate those strategies, in addition to its own mathematical intelligence, the LG algorithm may incorporate the intelligence of the top-level experts in the respective problem domains. LG models the individual differences between intelligent stakeholders. The LG tools make it possible to incorporate most of the known traits of a stakeholder, i.e., real personalities involved in

Incompressibility of asymmetric nuclear matter

International Nuclear Information System (INIS)

Chen, Liewen; Cai, Baojun; Shen, Chun; Ko, Cheming; Xu, Jun; Li, Baoan

2010-01-01

Using an isospin- and momentum-dependent modified Gogny (MDI) interaction, the Skyrme-Hartree-Fock (SHF) approach, and a phenomenological modified Skyrme-like (MSL) model, we have studied the incompressibility K sat (δ) of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of K sat (δ) in powers of isospin asymmetry δ, i.e., K sat (δ) = K 0 + K sat,2 δ 2 + K sat,4 δ 4 + O(δ 6 ), the magnitude of the 4th-order K sat,4 parameter is generally small. The 2nd-order K sat,2 parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matter at saturation density. Furthermore, the K sat,2 can be expressed as K sat,2 = K sym – 6L – J 0 /K 0 L in terms of the slope parameter L and the curvature parameter K sym of the symmetry energy and the third-order derivative parameter J 0 of the energy of symmetric nuclear matter at saturation density, and we find the higher order J 0 contribution to K sat,2 generally cannot be neglected. Also, we have found a linear correlation between K sym and L as well as between J 0 /K 0 and K 0 . Using these correlations together with the empirical constraints on K 0 and L, the nuclear symmetry energy E sym (ρ0) at normal nuclear density, and the nucleon effective mass, we have obtained an estimated value of K sat,2 = -370 ± 120 MeV for the 2nd-order parameter in the isospin asymmetry expansion of the incompressibility of asymmetric nuclear matter at its saturation density. (author)

Treatment outcome of bimaxillary surgery for asymmetric skeletal class II deformity.

Science.gov (United States)

Chen, Yun-Fang; Liao, Yu-Fang; Chen, Yin-An; Chen, Yu-Ray

2018-05-04

Facial asymmetry is one of the main concerns in patients with a dentofacial deformity. The aims of the study were to (1) evaluate the changes in facial asymmetry after bimaxillary surgery for asymmetric skeletal class II deformity and (2) compare preoperative and postoperative facial asymmetry of class II patients with normal controls. The facial asymmetry was assessed for 30 adults (21 women and 9 men, mean age: 29.3 years) who consecutively underwent bimaxillary surgery for asymmetric skeletal class II deformity using cone-beam computed tomography before and at least 6 months after surgery. Thirty soft tissue and two dental landmarks were identified on each three-dimensional facial image, and the asymmetry index of each landmark was calculated. Results were compared with those of 30 normal control subjects (21 women and 9 men, mean age: 26.2 years) with skeletal class I structure. Six months after surgery, the asymmetric index of the lower face and total face decreased significantly (17.8 ± 29.4 and 16.6 ± 29.5 mm, respectively, both p class II patients had residual chin asymmetry. The postoperative total face asymmetric index was positively correlated with the preoperative asymmetric index (r = 0.37, p class II deformity resulted in a significant improvement in lower face asymmetry. However, approximately 50% of the patients still had residual chin asymmetry. The total face postoperative asymmetry was moderately related to the initial severity of asymmetry. These findings could help clinicians better understand orthognathic outcomes on different facial regions for patients with asymmetric class II deformity.

Asymmetric ring structure of Vps4 required for ESCRT-III disassembly

Science.gov (United States)

Caillat, Christophe; Macheboeuf, Pauline; Wu, Yuanfei; McCarthy, Andrew A.; Boeri-Erba, Elisabetta; Effantin, Gregory; Göttlinger, Heinrich G.; Weissenhorn, Winfried; Renesto, Patricia

2015-12-01

The vacuolar protein sorting 4 AAA-ATPase (Vps4) recycles endosomal sorting complexes required for transport (ESCRT-III) polymers from cellular membranes. Here we present a 3.6-Å X-ray structure of ring-shaped Vps4 from Metallosphera sedula (MsVps4), seen as an asymmetric pseudohexamer. Conserved key interface residues are shown to be important for MsVps4 assembly, ATPase activity in vitro, ESCRT-III disassembly in vitro and HIV-1 budding. ADP binding leads to conformational changes within the protomer, which might propagate within the ring structure. All ATP-binding sites are accessible and the pseudohexamer binds six ATP with micromolar affinity in vitro. In contrast, ADP occupies one high-affinity and five low-affinity binding sites in vitro, consistent with conformational asymmetry induced on ATP hydrolysis. The structure represents a snapshot of an assembled Vps4 conformation and provides insight into the molecular motions the ring structure undergoes in a concerted action to couple ATP hydrolysis to ESCRT-III substrate disassembly.

The Impacts of Dry Dynamic Cores on Asymmetric Hurricane Intensification

Science.gov (United States)

Guimond, Stephen R.; Reisner, Jon M.; Marras, Simone; Giraldo, Francis X.

2016-01-01

The fundamental pathways for tropical cyclone (TC) intensification are explored by considering axisymmetric and asymmetric impulsive thermal perturbations to balanced, TC-like vortices using the dynamic cores of three different nonlinear numerical models. Attempts at reproducing the results of previous work, which used the community WRF Model, revealed a discrepancy with the impacts of purely asymmetric thermal forcing. The current study finds that thermal asymmetries can have an important, largely positive role on the vortex intensification, whereas other studies find that asymmetric impacts are negligible. Analysis of the spectral energetics of each numerical model indicates that the vortex response to asymmetric thermal perturbations is significantly damped in WRF relative to the other models. Spectral kinetic energy budgets show that this anomalous damping is primarily due to the increased removal of kinetic energy from the vertical divergence of the vertical pressure flux, which is related to the flux of inertia-gravity wave energy. The increased kinetic energy in the other two models is shown to originate around the scales of the heating and propagate upscale with time from nonlinear effects. For very large thermal amplitudes (50 K), the anomalous removal of kinetic energy due to inertia-gravity wave activity is much smaller, resulting in good agreement between models. The results of this paper indicate that the numerical treatment of small-scale processes that project strongly onto inertia-gravity wave energy can lead to significant differences in asymmetric TC intensification. Sensitivity tests with different time integration schemes suggest that diffusion entering into the implicit solution procedure is partly responsible for the anomalous damping of energy.

Nickel(0)-catalyzed enantioselective annulations of alkynes and arylenoates enabled by a chiral NHC ligand: efficient access to cyclopentenones.

Science.gov (United States)

Ahlin, Joachim S E; Donets, Pavel A; Cramer, Nicolai

2014-11-24

Cyclopentenones are versatile structural motifs of natural products as well as reactive synthetic intermediates. The nickel-catalyzed reductive [3+2] cycloaddition of α,β-unsaturated aromatic esters and alkynes constitutes an efficient method for their synthesis. Here, nickel(0) catalysts comprising a chiral bulky C1-symmetric N-heterocyclic carbene ligand were shown to enable an efficient asymmetric synthesis of cyclopentenones from mesityl enoates and internal alkynes under mild conditions. The bulky NHC ligand provided the cyclopentenone products in very high enantioselectivity and led to a regioselective incorporation of unsymmetrically substituted alkynes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High power CW output from low confinement asymmetric structure diode laser

NARCIS (Netherlands)

Iordache, G.; Buda, M.; Acket, G.A.; Roer, van de T.G.; Kaufmann, L.M.F.; Karouta, F.; Jagadish, C.; Tan, H.H.

1999-01-01

High power continuous wave output from diode lasers using low loss, low confinement, asymmetric structures is demonstrated. An asymmetric structure with an optical trap layer was grown by metal organic vapour phase epitaxy. Gain guided 50 µm wide stripe 1-3 mm long diode lasers were studied. 1.8 W

Asymmetric statistical features of the Chinese domestic and international gold price fluctuation

Science.gov (United States)

Cao, Guangxi; Zhao, Yingchao; Han, Yan

2015-05-01

Analyzing the statistical features of fluctuation is remarkably significant for financial risk identification and measurement. In this study, the asymmetric detrended fluctuation analysis (A-DFA) method was applied to evaluate asymmetric multifractal scaling behaviors in the Shanghai and New York gold markets. Our findings showed that the multifractal features of the Chinese and international gold spot markets were asymmetric. The gold return series persisted longer in an increasing trend than in a decreasing trend. Moreover, the asymmetric degree of multifractals in the Chinese and international gold markets decreased with the increase in fluctuation range. In addition, the empirical analysis using sliding window technology indicated that multifractal asymmetry in the Chinese and international gold markets was characterized by its time-varying feature. However, the Shanghai and international gold markets basically shared a similar asymmetric degree evolution pattern. The American subprime mortgage crisis (2008) and the European debt crisis (2010) enhanced the asymmetric degree of the multifractal features of the Chinese and international gold markets. Furthermore, we also make statistical tests for the results of multifractatity and asymmetry, and discuss the origin of them. Finally, results of the empirical analysis using the threshold autoregressive conditional heteroskedasticity (TARCH) and exponential generalized autoregressive conditional heteroskedasticity (EGARCH) models exhibited that good news had a more significant effect on the cyclical fluctuation of the gold market than bad news. Moreover, good news exerted a more significant effect on the Chinese gold market than on the international gold market.

Analysis of Surface Plasmon Resonance Curves with a Novel Sigmoid-Asymmetric Fitting Algorithm

Directory of Open Access Journals (Sweden)

Daeho Jang

2015-09-01

Full Text Available The present study introduces a novel curve-fitting algorithm for surface plasmon resonance (SPR curves using a self-constructed, wedge-shaped beam type angular interrogation SPR spectroscopy technique. Previous fitting approaches such as asymmetric and polynomial equations are still unsatisfactory for analyzing full SPR curves and their use is limited to determining the resonance angle. In the present study, we developed a sigmoid-asymmetric equation that provides excellent curve-fitting for the whole SPR curve over a range of incident angles, including regions of the critical angle and resonance angle. Regardless of the bulk fluid type (i.e., water and air, the present sigmoid-asymmetric fitting exhibited nearly perfect matching with a full SPR curve, whereas the asymmetric and polynomial curve fitting methods did not. Because the present curve-fitting sigmoid-asymmetric equation can determine the critical angle as well as the resonance angle, the undesired effect caused by the bulk fluid refractive index was excluded by subtracting the critical angle from the resonance angle in real time. In conclusion, the proposed sigmoid-asymmetric curve-fitting algorithm for SPR curves is widely applicable to various SPR measurements, while excluding the effect of bulk fluids on the sensing layer.

Cell chirality: its origin and roles in left-right asymmetric development.

Science.gov (United States)

Inaki, Mikiko; Liu, Jingyang; Matsuno, Kenji

2016-12-19

An item is chiral if it cannot be superimposed on its mirror image. Most biological molecules are chiral. The homochirality of amino acids ensures that proteins are chiral, which is essential for their functions. Chirality also occurs at the whole-cell level, which was first studied mostly in ciliates, single-celled protozoans. Ciliates show chirality in their cortical structures, which is not determined by genetics, but by 'cortical inheritance'. These studies suggested that molecular chirality directs whole-cell chirality. Intriguingly, chirality in cellular structures and functions is also found in metazoans. In Drosophila, intrinsic cell chirality is observed in various left-right (LR) asymmetric tissues, and appears to be responsible for their LR asymmetric morphogenesis. In other invertebrates, such as snails and Caenorhabditis elegans, blastomere chirality is responsible for subsequent LR asymmetric development. Various cultured cells of vertebrates also show intrinsic chirality in their cellular behaviours and intracellular structural dynamics. Thus, cell chirality may be a general property of eukaryotic cells. In Drosophila, cell chirality drives the LR asymmetric development of individual organs, without establishing the LR axis of the whole embryo. Considering that organ-intrinsic LR asymmetry is also reported in vertebrates, this mechanism may contribute to LR asymmetric development across phyla.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Authors.

Cell chirality: its origin and roles in left–right asymmetric development

Science.gov (United States)

Inaki, Mikiko; Liu, Jingyang

2016-01-01

An item is chiral if it cannot be superimposed on its mirror image. Most biological molecules are chiral. The homochirality of amino acids ensures that proteins are chiral, which is essential for their functions. Chirality also occurs at the whole-cell level, which was first studied mostly in ciliates, single-celled protozoans. Ciliates show chirality in their cortical structures, which is not determined by genetics, but by ‘cortical inheritance’. These studies suggested that molecular chirality directs whole-cell chirality. Intriguingly, chirality in cellular structures and functions is also found in metazoans. In Drosophila, intrinsic cell chirality is observed in various left–right (LR) asymmetric tissues, and appears to be responsible for their LR asymmetric morphogenesis. In other invertebrates, such as snails and Caenorhabditis elegans, blastomere chirality is responsible for subsequent LR asymmetric development. Various cultured cells of vertebrates also show intrinsic chirality in their cellular behaviours and intracellular structural dynamics. Thus, cell chirality may be a general property of eukaryotic cells. In Drosophila, cell chirality drives the LR asymmetric development of individual organs, without establishing the LR axis of the whole embryo. Considering that organ-intrinsic LR asymmetry is also reported in vertebrates, this mechanism may contribute to LR asymmetric development across phyla. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’. PMID:27821533

Creating biological nanomaterials using synthetic biology

International Nuclear Information System (INIS)

Rice, MaryJoe K; Ruder, Warren C

2014-01-01

Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems. (review)

Creating biological nanomaterials using synthetic biology.

Science.gov (United States)

Rice, MaryJoe K; Ruder, Warren C

2014-02-01

Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems.

Orientation- and position-controlled alignment of asymmetric silicon microrod on a substrate with asymmetric electrodes

Science.gov (United States)

Shibata, Akihide; Watanabe, Keiji; Sato, Takuya; Kotaki, Hiroshi; Schuele, Paul J.; Crowder, Mark A.; Zhan, Changqing; Hartzell, John W.; Nakatani, Ryoichi

2014-03-01

In this paper, we demonstrate the orientation-controlled alignment of asymmetric Si microrods on a glass substrate with an asymmetric pair of electrodes. The Si microrods have the shape of a paddle with a blade and a shaft part, and the pair of electrodes consists of a narrow electrode and a wide electrode. By applying AC bias to the electrodes, the Si microrods suspended in a fluid align in such a way to settle across the electrode pair, and over 80% of the aligned Si microrods have an orientation with the blade and the shaft of the paddle on the wide and the narrow electrodes, respectively. When Si microrods have a shell of dielectric film and its thickness on the top face is thicker than that on the bottom face, 97.8% of the Si microrods are aligned with the top face facing upwards. This technique is useful for orientation-controlled alignment of nano- and microsized devices that have polarity or a distinction between the top and bottom faces.

Synthetic Defects for Vibrothermography

Science.gov (United States)

Renshaw, Jeremy; Holland, Stephen D.; Thompson, R. Bruce; Eisenmann, David J.

2010-02-01

Synthetic defects are an important tool used for characterizing the performance of nondestructive evaluation techniques. Viscous material-filled synthetic defects were developed for use in vibrothermography (also known as sonic IR) as a tool to improve inspection accuracy and reliability. This paper describes how the heat-generation response of these VMF synthetic defects is similar to the response of real defects. It also shows how VMF defects can be applied to improve inspection accuracy for complex industrial parts and presents a study of their application in an aircraft engine stator vane.

Electromagnetic resonance in the asymmetric terahertz metamaterials with triangle microstructure

Science.gov (United States)

Xing, Yuanyuan; Zhang, Xiaoyu; Zhang, Qiang; Gu, Yanping; Qian, Yunan; Lin, Xingyue; Tang, Yunhai; Cheng, Xinli; Qin, Changfa; Shen, Jiaoyan; Zang, Taocheng; Ma, Chunlan

2018-05-01

We investigate terahertz transmission properties and electromagnetic resonance modes in the asymmetric triangle structures with the change of asymmetric distance and the direction of electric field. When the THz electric field is perpendicular to the split gap of triangle, the electric field can better excite the THz absorption in the triangle structures. Importantly, electromagnetically induced transparency (EIT) characteristics are observed in the triangle structures due to the destructive interference of the different excited modes. The distributions of electric field and surface current density simulated by finite difference time domain indicate that the bright mode is excited by the side of triangle structures and dark mode is excited by the gap-side of triangle. The present study is helpful to understand the electromagnetic resonance in the asymmetric triangular metamaterials.

Asymmetric adsorption of alanine by quartz powder from ethanol solution

Energy Technology Data Exchange (ETDEWEB)

Furuyama, Shozo; Sawada, Michio; Hachiya, Kinji; Morimoto, Tetsuo (Okayama Univ. (Japan). Faculty of Science)

1982-11-01

The asymmetric adsorption of the racemic alanine by the optically active quartz from ethanol solution at 8/sup 0/C was studied by the /sup 14/C-tracer method and the newly developed /sup 14/C-tracer ninhydrin-colorimetry combination method. The preferential adsorption of L-alanine by levorotatory quartz (l-quartz) and D-alanine by dextrorotatory quartz (d-quartz) was confirmed. The asymmetric adsorptivity (Asub(s)) falls in the range of 1.1 - 1.3, which is comparable with the value determined at - 80/sup 0/C in the previous paper. The effects of water content in the ethanol solution and of the adsorption temperature upon the adsorption affinity of alanine to quartz were also measured. The cause for the asymmetric adsorption is discussed from the crystallographic point of view.

Brownian Motion of Asymmetric Boomerang Colloidal Particles

Science.gov (United States)

Chakrabarty, Ayan; Konya, Andrew; Wang, Feng; Selinger, Jonathan; Sun, Kai; Wei, Qi-Huo

2014-03-01

We used video microscopy and single particle tracking to study the diffusion and local behaviors of asymmetric boomerang particles in a quasi-two dimensional geometry. The motion is biased towards the center of hydrodynamic stress (CoH) and the mean square displacements of the particles are linear at short and long times with different diffusion coefficients and in the crossover regime it is sub-diffusive. Our model based on Langevin theory shows that these behaviors arise from the non-coincidence of the CoH with the center of the body. Since asymmetric boomerangs represent a class of rigid bodies of more generals shape, therefore our findings are generic and true for any non-skewed particle in two dimensions. Both experimental and theoretical results will be discussed.

The synchronization of asymmetric-structured electric coupling neuronal system

Science.gov (United States)

Wang, Guanping; Jin, Wuyin; Liu, Hao; Sun, Wei

2018-02-01

Based on the Hindmarsh-Rose (HR) model, the synchronization dynamics of asymmetric-structured electric coupling two neuronal system is investigated in this paper. It is discovered that when the time-delay scope and coupling strength for the synchronization are correlated positively under unequal time delay, the time-delay difference does not make a clear distinction between the two individual inter-spike intervals (ISI) bifurcation diagrams of the two coupled neurons. Therefore, the superficial difference of the system synchronization dynamics is not obvious for the unequal time-delay feedback. In the asymmetrical current incentives under asymmetric electric coupled system, the two neurons can only be almost completely synchronized in specific area of the interval which end-pointed with two discharge modes for a single neuron under different stimuli currents before coupling, but the intervention of time-delay feedback, together with the change of the coupling strength, can make the coupled system not only almost completely synchronized within anywhere in the front area, but also outside of it.

Synthetic biology: Emerging bioengineering in Indonesia

Science.gov (United States)

Suhandono, Sony

2017-05-01

The development of synthetic biology will shape the new era of science and technology. It is an emerging bioengineering technique involving genetic engineering which can alter the phenotype and behavior of the cell or the new product. Synthetic biology may produce biomaterials, drugs, vaccines, biosensors, and even a recombinant secondary metabolite used in herbal and complementary medicine, such as artemisinin, a malaria drug which is usually extracted from the plant Artemisia annua. The power of synthetic biology has encouraged scientists in Indonesia, and is still in early development. This paper also covers some research from an Indonesian research institute in synthetic biology such as observing the production of bio surfactants and the enhanced production of artemisinin using a transient expression system. Synthetic biology development in Indonesia may also be related to the iGEM competition, a large synthetic biology research competition which was attended by several universities in Indonesia. The application of synthetic biology for drug discovery will be discussed.

Examining Theories of Distributive Justice with an Asymmetric Public Goods Game

Science.gov (United States)

Schmidt, Stephen J.

2015-01-01

In this article, the author presents an asymmetric version of the familiar public goods classroom experiment, in which some players are given more tokens to invest than others, and players collectively decide whether to divide the return to the group investment asymmetrically as well. The asymmetry between players raises normative issues about…

Rhodium/chiral diene-catalyzed asymmetric 1,4-addition of arylboronic acids to chromones: a highly enantioselective pathway for accessing chiral flavanones.

Science.gov (United States)

He, Qijie; So, Chau Ming; Bian, Zhaoxiang; Hayashi, Tamio; Wang, Jun

2015-03-01

Chromone has been noted to be one of the most challenging substrates in the asymmetric 1,4-addition of α,β-unsaturated carbonyl compounds. By employing the rhodium complex associated with a chiral diene ligand, (R,R)-Ph-bod*, the 1,4-addition of a variety of arylboronic acids was realized to give high yields of the corresponding flavanones with excellent enantioselectivities (≥97% ee, 99% ee for most substrates). Ring-opening side products, which would lead to erosion of product enantioselectivity, were not observed under the stated reaction conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Asymmetric Membranes Containing Micron-Size Silicon for High Performance Lithium Ion Battery Anode

International Nuclear Information System (INIS)

Byrd, Ian; Wu, Ji

2016-01-01

Micron-size Si anode is notorious for having extremely poor cycle life. It is mainly caused by the large volume change (∼300%) and poor mechanical strength of the Si electrode. Satisfying methods to address this issue are seriously lacking in literature. In this study, novel single-layer, double-layer and triple-layer asymmetric membranes containing micron-size silicon have been fabricated using a simple phase inversion method to dramatically improve its cyclability. The electrochemical performance of these asymmetric membranes as lithium ion battery anodes are evaluated and compared to pure micron-size Si powders and carbonaceous asymmetric membranes. All three types of asymmetric membrane electrodes demonstrate significantly enhanced stability as compared to pure Si powders. The single-layer asymmetric membrane has the largest capacity degradation due to the loss of pulverized Si powders from the membrane surface, only 40% of whose capacity can be retained in 100 cycles. But this performance is still much better than pure micron-size silicon electrode. After being coated with nanoporous carbonaceous layers on both sides of a single-layer asymmetric membrane to make a triple-layer asymmetric membrane (sandwich structure), the capacity retention is notably increased to 88% in 100 cycles at 610 mAh g"−"1 and 0.5C. The enhanced stability is attributed to the extra nanoporous coatings that can prevent the fractured Si powders from being leached out and allow facile lithium ion diffusions. Such a novel, efficient and scalable method may provide beneficiary guidance for designing high capacity lithium ion battery anodes with large volume change issues.

Metal-catalyzed Asymmetric Hetero-Diels-Alder Reactions of Unactivated Dienes with Glyoxylates

DEFF Research Database (Denmark)

Johannsen, Mogens; Yao, Sulan; Graven, Anette

1998-01-01

The development of a catalytic asymmetric hetero-Diels-Alder methodology for the reaction of unactivated dienes with glyoxylates is presented. Several different asymmetric catalysts can be used, but copper-bisoxazolines and aluminium-BINOL give the highest yield, and the best chemo...

The Synthetic Biology Open Language (SBOL) provides a community standard for communicating designs in synthetic biology.

Science.gov (United States)

Galdzicki, Michal; Clancy, Kevin P; Oberortner, Ernst; Pocock, Matthew; Quinn, Jacqueline Y; Rodriguez, Cesar A; Roehner, Nicholas; Wilson, Mandy L; Adam, Laura; Anderson, J Christopher; Bartley, Bryan A; Beal, Jacob; Chandran, Deepak; Chen, Joanna; Densmore, Douglas; Endy, Drew; Grünberg, Raik; Hallinan, Jennifer; Hillson, Nathan J; Johnson, Jeffrey D; Kuchinsky, Allan; Lux, Matthew; Misirli, Goksel; Peccoud, Jean; Plahar, Hector A; Sirin, Evren; Stan, Guy-Bart; Villalobos, Alan; Wipat, Anil; Gennari, John H; Myers, Chris J; Sauro, Herbert M

2014-06-01

The re-use of previously validated designs is critical to the evolution of synthetic biology from a research discipline to an engineering practice. Here we describe the Synthetic Biology Open Language (SBOL), a proposed data standard for exchanging designs within the synthetic biology community. SBOL represents synthetic biology designs in a community-driven, formalized format for exchange between software tools, research groups and commercial service providers. The SBOL Developers Group has implemented SBOL as an XML/RDF serialization and provides software libraries and specification documentation to help developers implement SBOL in their own software. We describe early successes, including a demonstration of the utility of SBOL for information exchange between several different software tools and repositories from both academic and industrial partners. As a community-driven standard, SBOL will be updated as synthetic biology evolves to provide specific capabilities for different aspects of the synthetic biology workflow.

A method of the asymmetric Abel's inversion in plasma diagnosis

International Nuclear Information System (INIS)

Matoba, Tohru; Funahashi, Akimasa

1975-09-01

In the case of a noncylindrical plasma, axis symmetric components are drawn from observed projected intensities of physical quantities, assuming an asymmetric form. And the radial intensity distribution is determined by Abel's inversion method. The best fitting curve is obtained analytically from measured values by the least-square estimation of nonlinear parameters. The cylindrical symmetric Abel's inversion code ( ABELIC ) and the asymmetric Abel's inversion code ( ABELILSENP 2 ) are described. (auth.)

Fluorescent nanohybrids based on asymmetrical cyanine dyes decorated carbon nanotubes

OpenAIRE

Çavuşlar, Özge; Cavuslar, Ozge

2015-01-01

In this thesis, we focused on imparting new optical properties to carbon nanotubes (CNTs) to allow their optical detection and visualization in biomedical applications. We investigated the interactions of CNTs and DNA wrapped CNTs with asymmetrical cyanine dye molecules to study the applicability of resulting hybrid materials to fluorescent based systems. When CNTs interacted with asymmetrical cyanine dyes, they constructed a light absorbing nanoarray. However, the fluorescence emission of th...

A Canadian refiner's perspective of synthetic crudes

International Nuclear Information System (INIS)

Halford, T.L.; McIntosh, A.P.; Rasmussen

1997-01-01

Some of the factors affecting a refiner's choice of crude oil include refinery hardware, particularly gas oil crackers, products slate and product specifications, crude availability, relative crude price and crude quality. An overview of synthetic crude, the use of synthetic crude combined with other crudes and a comparison of synthetic crude with conventional crude oil was given. The two main users of synthetic crude are basically two groups of refiners, those large groups who use synthetic crude combined with other crudes, and a smaller group who run synthetic crude on specially designed units as a sole feed. The effects of changes in fuel legislation were reviewed. It was predicted that the changes will have a mixed impact on the value of synthetic crude, but low sulphur diesel regulations and gasoline sulphur regulations will make current synthetic crudes attractive. The big future change with a negative impact will be diesel cetane increases to reduce engine emissions. This will reduce synthetic crude attractiveness due to distillate yields and quality and high gas oil yields. Similarly, any legislation limiting aromatics in diesel fuel will also make synthetic crudes less attractive. Problems experienced by refiners with hardware dedicated to synthetic crude (salt, naphthenic acid, fouling, quality variations) were also reviewed. 3 tabs

Asymmetric-shell ignition capsule design to tune the low-mode asymmetry during the peak drive

International Nuclear Information System (INIS)

Gu, Jianfa; Dai, Zhensheng; Song, Peng; Zou, Shiyang; Ye, Wenhua; Zheng, Wudi; Gu, Peijun; Wang, Jianguo; Zhu, Shaoping

2016-01-01

The low-mode radiation flux asymmetry in the hohlraum is a main source of performance degradation in the National Ignition Facility (NIF) implosion experiments. To counteract the deleterious effects of the large positive P2 flux asymmetry during the peak drive, this paper develops a new tuning method called asymmetric-shell ignition capsule design which adopts the intentionally asymmetric CH ablator layer or deuterium-tritium (DT) ice layer. A series of two-dimensional implosion simulations have been performed, and the results show that the intentionally asymmetric DT ice layer can significantly improve the fuel ρR symmetry, hot spot shape, hot spot internal energy, and the final neutron yield compared to the spherical capsule. This indicates that the DT asymmetric-shell capsule design is an effective tuning method, while the CH ablator asymmetric-shell capsule could not correct the fuel ρR asymmetry, and it is not as effective as the DT asymmetric-shell capsule design.

Asymmetric-shell ignition capsule design to tune the low-mode asymmetry during the peak drive

Science.gov (United States)

Gu, Jianfa; Dai, Zhensheng; Song, Peng; Zou, Shiyang; Ye, Wenhua; Zheng, Wudi; Gu, Peijun; Wang, Jianguo; Zhu, Shaoping

2016-08-01

The low-mode radiation flux asymmetry in the hohlraum is a main source of performance degradation in the National Ignition Facility (NIF) implosion experiments. To counteract the deleterious effects of the large positive P2 flux asymmetry during the peak drive, this paper develops a new tuning method called asymmetric-shell ignition capsule design which adopts the intentionally asymmetric CH ablator layer or deuterium-tritium (DT) ice layer. A series of two-dimensional implosion simulations have been performed, and the results show that the intentionally asymmetric DT ice layer can significantly improve the fuel ρR symmetry, hot spot shape, hot spot internal energy, and the final neutron yield compared to the spherical capsule. This indicates that the DT asymmetric-shell capsule design is an effective tuning method, while the CH ablator asymmetric-shell capsule could not correct the fuel ρR asymmetry, and it is not as effective as the DT asymmetric-shell capsule design.

Asymmetric-shell ignition capsule design to tune the low-mode asymmetry during the peak drive

Energy Technology Data Exchange (ETDEWEB)

Gu, Jianfa, E-mail: gu-jianfa@iapcm.ac.cn; Dai, Zhensheng, E-mail: dai-zhensheng@iapcm.ac.cn; Song, Peng; Zou, Shiyang; Ye, Wenhua; Zheng, Wudi; Gu, Peijun; Wang, Jianguo; Zhu, Shaoping [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2016-08-15

The low-mode radiation flux asymmetry in the hohlraum is a main source of performance degradation in the National Ignition Facility (NIF) implosion experiments. To counteract the deleterious effects of the large positive P2 flux asymmetry during the peak drive, this paper develops a new tuning method called asymmetric-shell ignition capsule design which adopts the intentionally asymmetric CH ablator layer or deuterium-tritium (DT) ice layer. A series of two-dimensional implosion simulations have been performed, and the results show that the intentionally asymmetric DT ice layer can significantly improve the fuel ρR symmetry, hot spot shape, hot spot internal energy, and the final neutron yield compared to the spherical capsule. This indicates that the DT asymmetric-shell capsule design is an effective tuning method, while the CH ablator asymmetric-shell capsule could not correct the fuel ρR asymmetry, and it is not as effective as the DT asymmetric-shell capsule design.

Asymmetric dark matter annihilation as a test of non-standard cosmologies

International Nuclear Information System (INIS)

Gelmini, Graciela B.; Huh, Ji-Haeng; Rehagen, Thomas

2013-01-01

We show that the relic abundance of the minority component of asymmetric dark matter can be very sensitive to the expansion rate of the Universe and the temperature of transition between a non-standard pre-Big Bang Nucleosynthesis cosmological phase and the standard radiation dominated phase, if chemical decoupling happens before this transition. In particular, because the annihilation cross section of asymmetric dark matter is typically larger than that of symmetric dark matter in the standard cosmology, the decrease in relic density of the minority component in non-standard cosmologies with respect to the majority component may be compensated by the increase in annihilation cross section, so that the annihilation rate at present of asymmetric dark matter, contrary to general belief, could be larger than that of symmetric dark matter in the standard cosmology. Thus, if the annihilation cross section of the asymmetric dark matter candidate is known, the annihilation rate at present, if detectable, could be used to test the Universe before Big Bang Nucleosynthesis, an epoch from which we do not yet have any data

[Au]/[Pd] Multicatalytic Processes: Direct One-Pot Access to Benzo[ c ]chromenes and Benzo[ b ]furans

KAUST Repository

Oonishi, Yoshihiro; Gó mez-Suá rez, Adriá n; Martin, Anthony R.; Makida, Yusuke; Slawin, Alexandra M. Z.; Nolan, Steven P.

2014-01-01

A new synthetic protocol that combines the advantages offered by eco-friendly solvent-free reactions and sequential transformations is reported. This strategy offers straightforward access to benzo[c]chromenes and benzo[b]furans from commercially

Asymmetric information and economics

Science.gov (United States)

Frieden, B. Roy; Hawkins, Raymond J.

2010-01-01

We present an expression of the economic concept of asymmetric information with which it is possible to derive the dynamical laws of an economy. To illustrate the utility of this approach we show how the assumption of optimal information flow leads to a general class of investment strategies including the well-known Q theory of Tobin. Novel consequences of this formalism include a natural definition of market efficiency and an uncertainty principle relating capital stock and investment flow.

Specifications of Standards in Systems and Synthetic Biology: Status and Developments in 2017

Directory of Open Access Journals (Sweden)

Schreiber Falk

2018-03-01

Full Text Available Standards are essential to the advancement of Systems and Synthetic Biology. COMBINE provides a formal body and a centralised platform to help develop and disseminate relevant standards and related resources. The regular special issue of the Journal of Integrative Bioinformatics aims to support the exchange, distribution and archiving of these standards by providing unified, easily citable access. This paper provides an overview of existing COMBINE standards and presents developments of the last year.

Finding Hope in Synthetic Biology.

Science.gov (United States)

Takala, Tuija

2017-04-01

For some, synthetic biology represents great hope in offering possible solutions to many of the world's biggest problems, from hunger to sustainable development. Others remain fearful of the harmful uses, such as bioweapons, that synthetic biology can lend itself to, and most hold that issues of biosafety are of utmost importance. In this article, I will evaluate these points of view and conclude that although the biggest promises of synthetic biology are unlikely to become reality, and the probability of accidents is fairly substantial, synthetic biology could still be seen to benefit humanity by enhancing our ethical understanding and by offering a boost to world economy.

Geo synthetic-reinforced Pavement systems

International Nuclear Information System (INIS)

Zornberg, J. G.

2014-01-01

Geo synthetics have been used as reinforcement inclusions to improve pavement performance. while there are clear field evidence of the benefit of using geo synthetic reinforcements, the specific conditions or mechanisms that govern the reinforcement of pavements are, at best, unclear and have remained largely unmeasured. Significant research has been recently conducted with the objectives of: (i) determining the relevant properties of geo synthetics that contribute to the enhanced performance of pavement systems, (ii) developing appropriate analytical, laboratory and field methods capable of quantifying the pavement performance, and (iii) enabling the prediction of pavement performance as a function of the properties of the various types of geo synthetics. (Author)

Asymmetric Michael Addition Mediated by Chiral Ionic Liquids.

Science.gov (United States)

Suzuki, Yumiko

2018-06-01

Chiral ionic liquids with a focus on their applications in asymmetric Michael additions and related reactions were reviewed. The examples were classified on the basis of the mode of asymmetric induction (e.g., external induction/non-covalent interaction or internal induction/covalent bond formation), the roles in reactions (as a solvent or catalyst), and their structural features (e.g., imidazolium-based chiral cations, other chiral oniums; proline derivatives). Most of the reactions with high chiral induction are Michael addition of ketones or aldehydes to chalcones or nitrostyrenes where proline-derived chiral ionic liquids catalyze the reaction through enamine/ iminium formation. Many reports demonstrate the recyclability of ionic liquid-tagged pyrrolidines.

Thomson scattering measurements from asymmetric interpenetrating plasma flows

Energy Technology Data Exchange (ETDEWEB)

Ross, J. S., E-mail: ross36@llnl.gov; Moody, J. D.; Fiuza, F.; Ryutov, D.; Divol, L.; Huntington, C. M.; Park, H.-S. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

2014-11-15

Imaging Thomson scattering measurements of collective ion-acoustic fluctuations have been utilized to determine ion temperature and density from laser produced counter-streaming asymmetric flows. Two foils are heated with 8 laser beams each, 500 J per beam, at the Omega Laser facility. Measurements are made 4 mm from the foil surface using a 60 J 2ω probe laser with a 200 ps pulse length. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the multi-ion species, asymmetric flows theoretical form factor for the ion feature such that the ion temperatures, ion densities, and flow velocities for each plasma flow are determined.

Decoding Pure Rotational Molecular Spectra for Asymmetric Molecules

Directory of Open Access Journals (Sweden)

S. A. Cooke

2013-01-01

Full Text Available Rotational spectroscopy can provide insights of unparalleled precision with respect to the wavefunctions of molecular systems that have relevance in fields as diverse as astronomy and biology. In this paper, we demonstrate how asymmetric molecular pure rotational spectra may be analyzed “pictorially” and with simple formulae. It is shown that the interpretation of such spectra relies heavily upon pattern recognition. The presentation of some common spectral line positions in near-prolate asymmetric rotational spectra provides a means by which spectral assignment, and approximate rotational constant determination, may be usefully explored. To aid in this endeavor we have created a supporting, free, web page and mobile web page.

Finite stage asymmetric repeated games: Both players' viewpoints

KAUST Repository

Li, Lichun

2017-01-05

In asymmetric zero-sum games, one player has superior information about the game over the other. It is known that the informed players (maximizer) face the tradeoff of exploiting its superior information at the cost of revealing its superior information, but the basic point of the uninformed player (minimizer)\\'s decision making remains unknown. This paper studies the finite stage asymmetric repeated games from both players\\' viewpoints, and derives that not only security strategies but also the opponents\\' corresponding best responses depends only on the informed player\\'s history action sequences. Moreover, efficient LP formulations to compute both player\\'s security strategies are provided.

Efficient Synthesis of Differentiated syn-1,2-Diol Derivatives by Asymmetric Transfer Hydrogenation-Dynamic Kinetic Resolution of α-Alkoxy-Substituted β-Ketoesters.

Science.gov (United States)

Monnereau, Laure; Cartigny, Damien; Scalone, Michelangelo; Ayad, Tahar; Ratovelomanana-Vidal, Virginie

2015-08-10

Asymmetric transfer hydrogenation was applied to a wide range of racemic aryl α-alkoxy-β-ketoesters in the presence of well-defined, commercially available, chiral catalyst Ru(II) -(N-p-toluenesulfonyl-1,2-diphenylethylenediamine) and a 5:2 mixture of formic acid and triethylamine as the hydrogen source. Under these conditions, dynamic kinetic resolution was efficiently promoted to provide the corresponding syn α-alkoxy-β-hydroxyesters derived from substituted aromatic and heteroaromatic aldehydes with a high level of diastereoselectivity (diastereomeric ratio (d.r.)>99:1) and an almost perfect enantioselectivity (enantiomeric excess (ee)>99 %). Additionally, after extensive screening of the reaction conditions, the use of Ru(II) - and Rh(III) -tethered precatalysts extended this process to more-challenging substrates that bore alkenyl-, alkynyl-, and alkyl substituents to provide the corresponding syn α-alkoxy-β-hydroxyesters with excellent enantiocontrol (up to 99 % ee) and good to perfect diastereocontrol (d.r.>99:1). Lastly, the synthetic utility of the present protocol was demonstrated by application to the asymmetric synthesis of chiral ester ethyl (2S)-2-ethoxy-3-(4-hydroxyphenyl)-propanoate, which is an important pharmacophore in a number of peroxisome proliferator-activated receptor α/γ dual agonist advanced drug candidates used for the treatment of type-II diabetes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent Advances in Substrate-Controlled Asymmetric Cyclization for Natural Product Synthesis

Directory of Open Access Journals (Sweden)

Jeyun Jo

2017-06-01

Full Text Available Asymmetric synthesis of naturally occurring diverse ring systems is an ongoing and challenging research topic. A large variety of remarkable reactions utilizing chiral substrates, auxiliaries, reagents, and catalysts have been intensively investigated. This review specifically describes recent advances in successful asymmetric cyclization reactions to generate cyclic architectures of various natural products in a substrate-controlled manner.

Simulation of seismic signals from asymmetric LANL hydrodynamic calculations

International Nuclear Information System (INIS)

Stevens, J.L.; Rimer, N.; Halda, E.J.; Barker, T.G.; Davis, C.G.; Johnson, W.E.

1993-01-01

Hydrodynamic calculations of an asymmetric nuclear explosion source were propagated to teleseismic distances to investigate the effects of the asymmetric source on seismic signals. The source is an explosion in a 12 meter long canister with the device at one end of the canister and a metal plate adjacent to the explosion. This produces a strongly asymmetric two-lobed source in the hydrodynamic region. The hydrodynamic source is propagated to the far field using a three-step process. The Eulerian hydrodynamic code SOIL was used by LANL to calculate the material velocity, density, and internal energy up to a time of 8.9 milliseconds after the explosion. These quantities were then transferred to an initial grid for the Lagrangian elastic/plastic finite difference code CRAM, which was used by S-CUBED to propagate the signal through the region of nonlinear deformation into the external elastic region. The cavity size and shape at the time of the overlay were determined by searching for a rapid density change in the SOIL grid, and this interior region was then rezoned into a single zone. The CRAM calculation includes material strength and gravity, and includes the effect of the free surface above the explosion. Finally, far field body waves were calculated by integrating over a closed surface in the elastic region and using the representation theorem. A second calculation was performed using an initially spherical source for comparison with the asymmetric calculation

Using real-estate-based financing to access capital.

Science.gov (United States)

Tobin, W C; Kryzaniak, L A

1998-07-01

One strategy employed by healthcare organizations to increase their market presence is the construction of new facilities. Accessing capital to fund such construction, however, has become more of a challenge. One relatively untapped source of building capital is real-estate-based financing. Nonrecourse mortgages, turnkey net leases, and synthetic leases can provide several advantages to healthcare organizations seeking capital, assuming issues related to building ownership, debt and balance sheet effects, and tax-exempt status have been thoroughly explored first.

Quantum computation in semiconductor quantum dots of electron-spin asymmetric anisotropic exchange

International Nuclear Information System (INIS)

Hao Xiang; Zhu Shiqun

2007-01-01

The universal quantum computation is obtained when there exists asymmetric anisotropic exchange between electron spins in coupled semiconductor quantum dots. The asymmetric Heisenberg model can be transformed into the isotropic model through the control of two local unitary rotations for the realization of essential quantum gates. The rotations on each qubit are symmetrical and depend on the strength and orientation of asymmetric exchange. The implementation of the axially symmetric local magnetic fields can assist the construction of quantum logic gates in anisotropic coupled quantum dots. This proposal can efficiently use each physical electron spin as a logical qubit in the universal quantum computation

Evaluation of the Perceptual Characteristics of a Force Induced by Asymmetric Vibrations.

Science.gov (United States)

Tanabe, Takeshi; Yano, Hiroaki; Iwata, Hiroo

2017-08-29

This paper describes the properties of proprioceptive sensations induced by asymmetric vibration using a vibration speaker-type non-grounded haptic interface. We confirm that the vibration speaker generates a perceived force that pulls or pushes a user's hand in a particular direction when an asymmetric amplitude signal that is generated by inverting a part of a sine wave is input. In this paper, to verify the system with respect to various factors of force perception caused by asymmetric vibration, we conducted six experiments and the following results were obtained. (1) The force vector can be controlled by reversing the asymmetric waves. (2) By investigating the physical characteristics of the vibration, asymmetric vibration was confirmed. (3) The presentation of vibration in the shear direction on the finger pad is effective. (4) The point of subjective equality of the perceived force can be controlled by up to 0.43 N by changing the amplitude voltage of the input signals. (5) The minimum stimulation time required for force perception is 66.7 ms. (6) When the vibration is continuously presented for 40 to 50 s, the perceived force decreases because of adaptation. Hence, we confirmed that we can control both the direction and magnitude of the reaction force by changing the input signal of the vibration speaker.

Asymmetrical Representation of Gender in Amharic1

African Journals Online (AJOL)

Administrator

in its grammar. Gender representation in this language is asymmetrical heavily ..... In dictionaries where. Amharic appears either as the target or the source language, verbs are entered ...... The Dialects of Amharic Revisited. Semitica et.

Asymmetric multi-fractality in the U.S. stock indices using index-based model of A-MFDFA

International Nuclear Information System (INIS)

Lee, Minhyuk; Song, Jae Wook; Park, Ji Hwan; Chang, Woojin

2017-01-01

Highlights: • ‘Index-based A-MFDFA’ model is proposed to assess the asymmetric multi-fractality. • The asymmetric multi-fractality in the U.S. stock indices are investigated using ‘Index-based’ and ‘Return-based’ A-MFDFA. • The asymmetric feature is more significantly identified by ‘Index-based’ model than ‘return-based’ model. • Source of multi-fractality and time-varying features are analyzed. - Abstract: We detect the asymmetric multi-fractality in the U.S. stock indices based on the asymmetric multi-fractal detrended fluctuation analysis (A-MFDFA). Instead using the conventional return-based approach, we propose the index-based model of A-MFDFA where the trend based on the evolution of stock index rather than stock price return plays a role for evaluating the asymmetric scaling behaviors. The results show that the multi-fractal behaviors of the U.S. stock indices are asymmetric and the index-based model detects the asymmetric multi-fractality better than return-based model. We also discuss the source of multi-fractality and its asymmetry and observe that the multi-fractal asymmetry in the U.S. stock indices has a time-varying feature where the degree of multi-fractality and asymmetry increase during the financial crisis.

Asymmetric quantum cloning machines

International Nuclear Information System (INIS)

Cerf, N.J.

1998-01-01

A family of asymmetric cloning machines for quantum bits and N-dimensional quantum states is introduced. These machines produce two approximate copies of a single quantum state that emerge from two distinct channels. In particular, an asymmetric Pauli cloning machine is defined that makes two imperfect copies of a quantum bit, while the overall input-to-output operation for each copy is a Pauli channel. A no-cloning inequality is derived, characterizing the impossibility of copying imposed by quantum mechanics. If p and p ' are the probabilities of the depolarizing channels associated with the two outputs, the domain in (√p,√p ' )-space located inside a particular ellipse representing close-to-perfect cloning is forbidden. This ellipse tends to a circle when copying an N-dimensional state with N→∞, which has a simple semi-classical interpretation. The symmetric Pauli cloning machines are then used to provide an upper bound on the quantum capacity of the Pauli channel of probabilities p x , p y and p z . The capacity is proven to be vanishing if (√p x , √p y , √p z ) lies outside an ellipsoid whose pole coincides with the depolarizing channel that underlies the universal cloning machine. Finally, the tradeoff between the quality of the two copies is shown to result from a complementarity akin to Heisenberg uncertainty principle. (author)

Monte Carlo simulation of asymmetrical growth of cube-shaped nanoparticles

International Nuclear Information System (INIS)

Wang Yuanyuan; Xie Huaqing; Wu Zihua; Xing Jiaojiao

2016-01-01

We simulated the asymmetrical growth of cube-shaped nanoparticles by applying the Monte Carlo method. The influence of the specific mechanisms on the crystal growth of nanoparticles has been phenomenologically described by efficient growth possibilities along different directions (or crystal faces). The roles of the thermodynamic and kinetic factors have been evaluated in three phenomenological models. The simulation results would benefit the understanding about the cause and manner of the asymmetrical growth of nanoparticles. (paper)

Models for synthetic biology.

Science.gov (United States)

Kaznessis, Yiannis N

2007-11-06

Synthetic biological engineering is emerging from biology as a distinct discipline based on quantification. The technologies propelling synthetic biology are not new, nor is the concept of designing novel biological molecules. What is new is the emphasis on system behavior. The objective is the design and construction of new biological devices and systems to deliver useful applications. Numerous synthetic gene circuits have been created in the past decade, including bistable switches, oscillators, and logic gates, and possible applications abound, including biofuels, detectors for biochemical and chemical weapons, disease diagnosis, and gene therapies. More than fifty years after the discovery of the molecular structure of DNA, molecular biology is mature enough for real quantification that is useful for biological engineering applications, similar to the revolution in modeling in chemistry in the 1950s. With the excitement that synthetic biology is generating, the engineering and biological science communities appear remarkably willing to cross disciplinary boundaries toward a common goal.

Optical CDMA and WDMA in the access network

Science.gov (United States)

Sargent, Edward H.; Stok, Andrew

2003-08-01

Optical CDMA provides one avenue to sharing the vast bandwidth of optical fiber among a number of active users in a network. In this work we address two questions central to considering the areas of applicability of CDMA in optics: (1) How do we compare fairly optical CDMA codes of different families, and what do we conclude? (2) How do we compare optical CDMA performance with that of conventional optical WDMA? To answer the first question, we present a method of comparing optical CDMA codes of different families, sizes and weights. We outline why the traditional performance metric of bit-error rate versus number of simultaneous users is lacking and propose a different performance measure -- the peak throughput normalized with respect to the size of the code. This metric is used to show that optical-orthogonal codes (OOCs) with a weight of 4 perform best at low offered loads while OOCs with weight 5 should be used at higher offered loads. By applying the technique across different families of codes, we demonstrate that multi-wavelength OOCs (MWOOCs) perform better than both OOCs (by a factor of approximately 1.25) and asymmetric prime-hop codes (by a factor of approximately 3.5), over a wide range of offered loads. In answer to the second question, we present a comparison of the performance of optical code-division multiple-access (CDMA) systems with that of a wavelength-division multiple-access (WDMA) system. The multiple-access techniques are applied in a time-slotted broadcast local-area network. The utilization, defined as the throughput per unit of time-domain bandwidth expansion, and packet delay are used as metrics of performance. When more than seven wavelengths are available, optical CDMA systems using asymmetric prime-hop codes and all-optical signal processing are shown to have higher peak utilization and lower corresponding delay than a WDMA system with the same number of wavelengths. When the encoders/decoders operate at the chip rate, the utilization

Porous asymmetric SiO2-g-PMMA nanoparticles produced by phase inversion

KAUST Repository

Munirasu, Selvaraj

2014-07-22

A new kind of asymmetric organic-inorganic porous structure has been proposed. Asymmetric lattices of polymer grafted silica nanoparticles were manufactured by casting and phase inversion in water. Silica nanoparticles were first functionalized with 3-(dimethylethoxysilyl)propyl-2-bromoisobutyrate, followed by grafting of poly(methylmethacrylate) (PMMA) segments, performed by atom-transfer radical polymerization. Mechanically stable self-standing films were prepared by casting a dispersion of functionalized nanoparticles in different solvents and immersion in water. The resulting asymmetrically porous morphology and nanoparticle assembly was characterized by scanning electron and atomic force microscopy. The PMMA functionalized SiO2 hybrid material in acetone or acetone/dioxane led to the best-assembled structures. Porous asymmetric membranes were prepared by adding free PMMA and PMMA terminated with hydrophilic hydroxyl group. Nitrogen flow of 2800 L m-2 h -1 was measured at 1.3 bar demonstrating the porosity and potential application for membrane technology. © 2014 Springer Science+Business Media New York.

Some Families of Asymmetric Quantum MDS Codes Constructed from Constacyclic Codes

Science.gov (United States)

Huang, Yuanyuan; Chen, Jianzhang; Feng, Chunhui; Chen, Riqing

2018-02-01

Quantum maximal-distance-separable (MDS) codes that satisfy quantum Singleton bound with different lengths have been constructed by some researchers. In this paper, seven families of asymmetric quantum MDS codes are constructed by using constacyclic codes. We weaken the case of Hermitian-dual containing codes that can be applied to construct asymmetric quantum MDS codes with parameters [[n,k,dz/dx

Hierarchical polypyrrole based composites for high performance asymmetric supercapacitors

Science.gov (United States)

Chen, Gao-Feng; Liu, Zhao-Qing; Lin, Jia-Ming; Li, Nan; Su, Yu-Zhi

2015-06-01

An advanced asymmetric supercapacitor with high energy density, exploiting hierarchical polypyrrole (PPy) based composites as both the anode [three dimensional (3D) chuzzle-like Ni@PPy@MnO2] and (3D cochleate-like Ni@MnO2@PPy) cathode, has been developed. The ultrathin PPy and flower-like MnO2 orderly coating on the high-conductivity 3D-Ni enhance charge storage while the unique 3D chuzzle-like and 3D cochleate-like structures provide storage chambers and fast ion transport pathways for benefiting the transport of electrolyte ions. The 3D cochleate-like Ni@MnO2@PPy possesses excellent pseudocapacitance with a relatively negative voltage window while preserved EDLC and free transmission channels conducive to hold the high power, providing an ideal cathode for the asymmetric supercapacitor. It is the first report of assembling hierarchical PPy based composites as both the anode and cathode for asymmetric supercapacitor, which exhibits wide operation voltage of 1.3-1.5 V with maximum energy and power densities of 59.8 Wh kg-1 and 7500 W kg-1.

Asymmetric total synthesis of cladosporin and isocladosporin.

Science.gov (United States)

Zheng, Huaiji; Zhao, Changgui; Fang, Bowen; Jing, Peng; Yang, Juan; Xie, Xingang; She, Xuegong

2012-07-06

The first asymmetric total syntheses of cladosporin and isocladosporin were accomplished in 8 steps with 8% overall yield and 10 steps with 26% overall yield, respectively. The relative configuration of isocladosporin was determined via this total synthesis.

Asymmetric Michael Addition Mediated by Chiral Ionic Liquids

Science.gov (United States)

Suzuki, Yumiko

2018-01-01

Chiral ionic liquids with a focus on their applications in asymmetric Michael additions and related reactions were reviewed. The examples were classified on the basis of the mode of asymmetric induction (e.g., external induction/non-covalent interaction or internal induction/covalent bond formation), the roles in reactions (as a solvent or catalyst), and their structural features (e.g., imidazolium-based chiral cations, other chiral oniums; proline derivatives). Most of the reactions with high chiral induction are Michael addition of ketones or aldehydes to chalcones or nitrostyrenes where proline-derived chiral ionic liquids catalyze the reaction through enamine/ iminium formation. Many reports demonstrate the recyclability of ionic liquid-tagged pyrrolidines. PMID:29861702

Free-Standing Bilayered Nanoparticle Superlattice Nanosheets with Asymmetric Ionic Transport Behaviors.

Science.gov (United States)

Rao, Siyuan; Si, Kae Jye; Yap, Lim Wei; Xiang, Yan; Cheng, Wenlong

2015-11-24

Natural cell membranes can directionally and selectively regulate the ion transport, which is critical for the functioning of living cells. Here, we report on the fabrication of an artificial membrane based on an asymmetric nanoparticle superlattice bilayered nanosheet, which exhibits similar ion transport characteristics. The superlattice nanosheets were fabricated via a drying-mediated self-assembly of polystyrene-capped gold nanoparticles at the liquid-air interface. By adopting a layer-by-layer assembly process, an asymmetric nanomembrane could be obtained consisting of two nanosheets with different nanoparticle size. The resulting nanomembranes exhibit an asymmetric ion transport behavior, and diode-like current-voltage curves were observed. The asymmetric ion transport is attributed to the cone-like nanochannels formed within the membranes, upon which a simulation map was established to illustrate the relationship between the channel structure and the ionic selectivity, in consistency with our experimental results. Our superlattice nanosheet-based design presents a promising strategy for the fabrication of next-generation smart nanomembranes for rationally and selectively regulating the ion transport even at a large ion flux, with potential applications in a wide range of fields, including biosensor devices, energy conversion, biophotonics, and bioelectronics.

A mean-field theory on the differential capacitance of asymmetric ionic liquid electrolytes.

Science.gov (United States)

Han, Yining; Huang, Shanghui; Yan, Tianying

2014-07-16

The size of ions significantly influences the electric double layer structure of room temperature ionic liquid (IL) electrolytes and their differential capacitance (Cd). In this study, we extended the mean-field theory (MFT) developed independently by Kornyshev (2007J. Phys. Chem. B 111 5545-57) and Kilic, Bazant, and Ajdari (2007 Phys. Rev. E 75 021502) (the KKBA MFT) to take into account the asymmetric 1:1 IL electrolytes by introducing an additional parameter ξ for the anion/cation volume ratio, besides the ionic compressibility γ in the KKBA MFT. The MFT of asymmetric ions becomes KKBA MFT upon ξ = 1, and further reduces to Gouy-Chapman theory in the γ → 0 limit. The result of the extended MFT demonstrates that the asymmetric ILs give rise to an asymmetric Cd, with the higher peak in Cd occurring at positive polarization for the smaller anionic size. At high potential, Cd decays asymptotically toward KKBA MFT characterized by γ for the negative polarization, and characterized by ξγ for the positive polarization, with inverse-square-root behavior. At low potential, around the potential of zero charge, the asymmetric ions cause a higher Cd, which exceeds that of Gouy-Chapman theory.

Volume inequalities for asymmetric Wulff shapes

OpenAIRE

Schuster, Franz E.; Weberndorfer, Manuel

2012-01-01

Sharp reverse affine isoperimetric inequalities for asymmetric Wulff shapes and their polars are established, along with the characterization of all extremals. These new inequalities have as special cases previously obtained simplex inequalities by Ball, Barthe and Lutwak, Yang, and Zhang. In particular, they provide the solution to a problem by Zhang.

Migration and Morphology of Asymmetric Barchans in the Central Hexi Corridor of Northwest China

Directory of Open Access Journals (Sweden)

Zhengcai Zhang

2018-06-01

Full Text Available Crescent-shaped barchan dunes often display an asymmetric shape, with one limb longer than the other. As shown in previous studies, asymmetric bimodal winds constitute one major cause of barchan asymmetry, but the heterogeneous conditions of sand availability or flux, as well as topographic influences, may be also important. Understanding the morphology and dynamics of asymmetric barchans may have an impact in a broad range of areas, particularly as these dunes may serve as a proxy for planetary wind regimes and soil conditions in extraterrestrial environments. However, in addition to the existing theories and numerical models that explain barchan asymmetry, direct measurements of migration rates and morphologic changes of real asymmetric barchans over a time span of several years would be beneficial. Therefore, here we report such measurements, which we have acquired by investigating asymmetric barchans in the Hexi Corridor, northwest of China. We have found that dune interactions and asymmetric influx conditions are the most important causes of barchan asymmetry in this field. Particle size distributions in the Hexi Corridor display strong variations over different parts of the asymmetric barchans, as well as over different dunes, with gravel particles being incorporated from the substrate as the dunes migrate. Our observations have shown that upwind sediment sources are important for dune formation in the Hexi Corridor, and that interdune interactions affect dune shape in different ways, depending on their offset. The asymmetric barchans in the Hexi Corridor are active, with an average migration rate (MR between 8 and 53 m year−1, in spite of the different asymmetric shapes. Our data for dune migration rates can be described well by a scaling of MR = A/(W + W0, where W is the barchan cross-wind width, A ≈ 2835 m2 s−1, and W0 ≈ 44 m. A similar scaling fits very well the migration rate as a function of dune along-wind width L, (i.e., MR

Chiral ferrocenes in asymmetric catalysis: synthesis and applications

National Research Council Canada - National Science Library

Dai, Li-Xin; Hou, Xue-Long

2010-01-01

.... It provides a thorough overview of the synthesis and characterization of different types of chiral ferrocene ligands, their application to various catalytic asymmetric reactions, and versatile chiral...

Instantaneous sediment transport model for asymmetric oscillatory sheet flow.

Directory of Open Access Journals (Sweden)

Xin Chen

Full Text Available On the basis of advanced concentration and velocity profiles above a mobile seabed, an instantaneous analytical model is derived for sediment transport in asymmetric oscillatory flow. The applied concentration profile is obtained from the classical exponential law based on mass conservation, and asymmetric velocity profile is developed following the turbulent boundary layer theory and the asymmetric wave theory. The proposed model includes two parts: the basic part that consists of erosion depth and free stream velocity, and can be simplified to the total Shields parameter power 3/2 in accordance with the classical empirical models, and the extra vital part that consists of phase-lead, boundary layer thickness and erosion depth. The effects of suspended sediment, phase-lag and asymmetric boundary layer development are considered particularly in the model. The observed instantaneous transport rate proportional to different velocity exponents due to phase-lag is unified and summarised by the proposed model. Both instantaneous and half period empirical formulas are compared with the developed model, using extensive data on a wide range of flow and sediment conditions. The synchronous variation in instantaneous transport rate with free stream velocity and its decrement caused by increased sediment size are predicted correctly. Net transport rates, especially offshore transport rates with large phase-lag under velocity skewed flows, which existing instantaneous type formulas failed to predict, are predicted correctly in both direction and magnitude by the proposed model. Net sediment transport rates are affected not only by suspended sediment and phase-lag, but also by the boundary layer difference between onshore and offshore.

Predicting tensorial electrophoretic effects in asymmetric colloids

Science.gov (United States)

Mowitz, Aaron J.; Witten, T. A.

2017-12-01

We formulate a numerical method for predicting the tensorial linear response of a rigid, asymmetrically charged body to an applied electric field. This prediction requires calculating the response of the fluid to the Stokes drag forces on the moving body and on the countercharges near its surface. To determine the fluid's motion, we represent both the body and the countercharges using many point sources of drag known as Stokeslets. Finding the correct flow field amounts to finding the set of drag forces on the Stokeslets that is consistent with the relative velocities experienced by each Stokeslet. The method rigorously satisfies the condition that the object moves with no transfer of momentum to the fluid. We demonstrate that a sphere represented by 1999 well-separated Stokeslets on its surface produces flow and drag force like a solid sphere to 1% accuracy. We show that a uniformly charged sphere with 3998 body and countercharge Stokeslets obeys the Smoluchowski prediction [F. Morrison, J. Colloid Interface Sci. 34, 210 (1970), 10.1016/0021-9797(70)90171-2] for electrophoretic mobility when the countercharges lie close to the sphere. Spheres with dipolar and quadrupolar charge distributions rotate and translate as predicted analytically to 4% accuracy or better. We describe how the method can treat general asymmetric shapes and charge distributions. This method offers promise as a way to characterize and manipulate asymmetrically charged colloid-scale objects from biology (e.g., viruses) and technology (e.g., self-assembled clusters).

0114 + 074 - A very asymmetric galaxy in the field of an intermediate-redshift QSO

International Nuclear Information System (INIS)

Akujor, C.E.

1989-01-01

New radio-continuum observations of 0114 + 074 (4C 07.4) are presented. It is shown that this radio source consists of two distinct objects: a point source identified with an 18.0 mag QSO and a highly asymmetric 18.5 mag galaxy. The patently asymmetric structure of the galaxy is most plausibly due to intrinsically asymmetric energy funding of the lobes by the central machine or nucleus, rather than external influences. 41 refs

Outage Analysis of Asymmetric RF-FSO Systems

KAUST Repository

Ansari, Imran Shafique; Abdallah, Mohamed M.; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

2017-01-01

In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channels cascaded with free-space optical (FSO) links is presented. The RF links are modeled by the Rayleigh fading

Meeting Report: Synthetic Biology Jamboree for Undergraduates

Science.gov (United States)

Campbell, A. Malcolm

2005-01-01

The field of synthetic biology (the name is derived from an analogy to synthetic chemistry) has recognized itself as a "field" only since about 2002. Synthetic biology has gotten some high-profile attention recently, but most people are not aware the field even exists. Synthetic biologists apply engineering principles to genomic circuits to…

21 CFR 73.1200 - Synthetic iron oxide.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Synthetic iron oxide. 73.1200 Section 73.1200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically prepared...

21 CFR 73.200 - Synthetic iron oxide.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Synthetic iron oxide. 73.200 Section 73.200 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.200 Synthetic iron oxide. (a) Identity. (1) The color additive synthetic iron oxide consists of any one or any combination of synthetically prepared...

21 CFR 172.888 - Synthetic petroleum wax.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Synthetic petroleum wax. 172.888 Section 172.888... CONSUMPTION Multipurpose Additives § 172.888 Synthetic petroleum wax. Synthetic petroleum wax may be safely used in or on foods in accordance with the following conditions: (a) Synthetic petroleum wax is a...

Asymmetric Flexible MXene-Reduced Graphene Oxide Micro-Supercapacitor

KAUST Repository

Couly, Cedric

2017-11-27

Current microfabrication of micro-supercapacitors often involves multistep processing and delicate lithography protocols. In this study, simple fabrication of an asymmetric MXene-based micro-supercapacitor that is flexible, binder-free, and current-collector-free is reported. The interdigitated device architecture is fabricated using a custom-made mask and a scalable spray coating technique onto a flexible, transparent substrate. The electrode materials are comprised of titanium carbide MXene (Ti3C2Tx) and reduced graphene oxide (rGO), which are both 2D layered materials that contribute to the fast ion diffusion in the interdigitated electrode architecture. This MXene-based asymmetric micro-supercapacitor operates at a 1 V voltage window, while retaining 97% of the initial capacitance after ten thousand cycles, and exhibits an energy density of 8.6 mW h cm−3 at a power density of 0.2 W cm−3. Further, these micro-supercapacitors show a high level of flexibility during mechanical bending. Utilizing the ability of Ti3C2Tx-MXene electrodes to operate at negative potentials in aqueous electrolytes, it is shown that using Ti3C2Tx as a negative electrode and rGO as a positive one in asymmetric architectures is a promising strategy for increasing both energy and power densities of micro-supercapacitors.

Recovery of the Aharonov-Bohm oscillations in asymmetrical quantum rings

Energy Technology Data Exchange (ETDEWEB)

Voskoboynikov, O., E-mail: vam@faculty.nctu.edu.tw [Department of Electronics Engineering, National Chiao Tung University, Hsinchu, Taiwan (China)

2016-07-15

We theoretically investigate suppression and recovery of the Aharonov-Bohm oscillations of the diamagnetic response of electrons (holes) confined in self-assembled In{sub c}Ga{sub 1−c}As/GaAs semiconductor reflection asymmetrical quantum rings. Based on the mapping method and gauge-origin-independent definition for the magnetic vector potential we simulate the energies and wave functions of the electron (hole) under external magnetic and electric fields. We examine the transformation of the ground state wave function of the electron (hole) in reflection asymmetrical rings from localized in one of the potential valleys (dotlike shape of the wave function) to distributed over all volume of the ring (ringlike shape) under an appropriate lateral electric field. This transformation greatly recovers the electron (hole) diamagnetic coefficient and Aharonov-Bohm oscillations of the diamagnetic response of the ring. However, the recovering electric field for the first Aharonov-Bohm diamagnetic oscillation of the electron is a suppressing one for the hole (and vice versa). This can block the recovery of the optical Aharonow-Bohm effect in In{sub c}Ga{sub 1−c}As/GaAs asymmetrically wobbled rings. However, the recovery of the Aharonov-Bohm oscillations for the independent electron (hole) by the external electric field remains interesting and feasible objective for the asymmetric rings.

An intrinsically asymmetric radio galaxy: 0500+630?

Science.gov (United States)

Saikia, D. J.; Thomasson, P.; Jackson, N.; Salter, C. J.; Junor, W.

1996-10-01

As part of a search for high-luminosity radio galaxies with one-sided structures, the radio galaxy 0500+630 has been imaged with both the VLA and MERLIN and its optical spectrum determined using the Isaac Newton Telescope on La Palma. The galaxy is found to have a redshift of 0.290+/-0.004. The radio observations show the source to be highly asymmetric, with an overall structure which cannot be understood easily by ascribing it either to orientation and relativistic beaming effects or to an asymmetric distribution of gas in the central region. A comparison of this source with objects of similar luminosity suggests that it is one of the best examples yet of a source with possibly an intrinsic asymmetry in either the collimation of its jets or the supply of energy from the central engine to opposite sides.

Improved DFIG Capability during Asymmetrical Grid Faults

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede

2015-01-01

In the wind power application, different asymmetrical types of the grid fault can be categorized after the Y/d transformer, and the positive and negative components of a single-phase fault, phase-to-phase fault, and two-phase fault can be summarized. Due to the newly introduced negative and even...... the natural component of the Doubly-Fed Induction Generator (DFIG) stator flux during the fault period, their effects on the rotor voltage can be investigated. It is concluded that the phase-to-phase fault has the worst scenario due to its highest introduction of the negative stator flux. Afterwards......, the capability of a 2 MW DFIG to ride through asymmetrical grid faults can be estimated at the existing design of the power electronics converter. Finally, a control scheme aimed to improve the DFIG capability is proposed and the simulation results validate its feasibility....

High-Stacking-Density, Superior-Roughness LDH Bridged with Vertically Aligned Graphene for High-Performance Asymmetric Supercapacitors.

Science.gov (United States)

Guo, Wei; Yu, Chang; Li, Shaofeng; Yang, Juan; Liu, Zhibin; Zhao, Changtai; Huang, Huawei; Zhang, Mengdi; Han, Xiaotong; Niu, Yingying; Qiu, Jieshan

2017-10-01

The high-performance electrode materials with tuned surface and interface structure and functionalities are highly demanded for advanced supercapacitors. A novel strategy is presented to conFigure high-stacking-density, superior-roughness nickel manganese layered double hydroxide (LDH) bridged by vertically aligned graphene (VG) with nickel foam (NF) as the conductive collector, yielding the LDH-NF@VG hybrids for asymmetric supercapacitors. The VG nanosheets provide numerous electron transfer channels for quick redox reactions, and well-developed open structure for fast mass transport. Moreover, the high-stacking-density LDH grown and assembled on VG nanosheets result in a superior hydrophilicity derived from the tuned nano/microstructures, especially microroughness. Such a high stacking density with abundant active sites and superior wettability can be easily accessed by aqueous electrolytes. Benefitting from the above features, the LDH-NF@VG can deliver a high capacitance of 2920 F g -1 at a current density of 2 A g -1 , and the asymmetric supercapacitor with the LDH-NF@VG as positive electrode and activated carbon as negative electrode can deliver a high energy density of 56.8 Wh kg -1 at a power density of 260 W kg -1 , with a high specific capacitance retention rate of 87% even after 10 000 cycles. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An optical tweezer in asymmetrical vortex Bessel-Gaussian beams

Energy Technology Data Exchange (ETDEWEB)

Kotlyar, V. V.; Kovalev, A. A., E-mail: alexeysmr@mail.ru; Porfirev, A. P. [Image Processing Systems Institute, 151 Molodogvardeiskaya St., 443001 Samara (Russian Federation); Department of Technical cybernetics, Samara State Aerospace University, Samara 443086 (Russian Federation)

2016-07-14

We study an optical micromanipulation that comprises trapping, rotating, and transporting 5-μm polystyrene microbeads in asymmetric Bessel-Gaussian (BG) laser beams. The beams that carry orbital angular momentum are generated by means of a liquid crystal microdisplay and focused by a microobjective with a numerical aperture of NA = 0.85. We experimentally show that given a constant topological charge, the rate of microparticle motion increases near linearly with increasing asymmetry of the BG beam. Asymmetric BG beams can be used instead of conventional Gaussian beam for trapping and transferring live cells without thermal damage.

Synthetic biology: programming cells for biomedical applications.

Science.gov (United States)

Hörner, Maximilian; Reischmann, Nadine; Weber, Wilfried

2012-01-01

The emerging field of synthetic biology is a novel biological discipline at the interface between traditional biology, chemistry, and engineering sciences. Synthetic biology aims at the rational design of complex synthetic biological devices and systems with desired properties by combining compatible, modular biological parts in a systematic manner. While the first engineered systems were mainly proof-of-principle studies to demonstrate the power of the modular engineering approach of synthetic biology, subsequent systems focus on applications in the health, environmental, and energy sectors. This review describes recent approaches for biomedical applications that were developed along the synthetic biology design hierarchy, at the level of individual parts, of devices, and of complex multicellular systems. It describes how synthetic biological parts can be used for the synthesis of drug-delivery tools, how synthetic biological devices can facilitate the discovery of novel drugs, and how multicellular synthetic ecosystems can give insight into population dynamics of parasites and hosts. These examples demonstrate how this new discipline could contribute to novel solutions in the biopharmaceutical industry.

Role of Synthetic and Dimensional Synthetic Organic Chemistry in Block Copolymer Micelle Nanosensor Engineering

DEFF Research Database (Denmark)

Ek, Pramod Kumar

This thesis investigated the role of amphiphilic triblock copolymer micelle nanomaterials in nanosensors, with emphasis on the synthesis of micelle particle sensors. The thesis is focused on the role of synthetic and dimensional synthetic organic chemistry in amphiphilic triblock core-shellcorona...

Gaze-Stabilizing Central Vestibular Neurons Project Asymmetrically to Extraocular Motoneuron Pools.

Science.gov (United States)

Schoppik, David; Bianco, Isaac H; Prober, David A; Douglass, Adam D; Robson, Drew N; Li, Jennifer M B; Greenwood, Joel S F; Soucy, Edward; Engert, Florian; Schier, Alexander F

2017-11-22

Within reflex circuits, specific anatomical projections allow central neurons to relay sensations to effectors that generate movements. A major challenge is to relate anatomical features of central neural populations, such as asymmetric connectivity, to the computations the populations perform. To address this problem, we mapped the anatomy, modeled the function, and discovered a new behavioral role for a genetically defined population of central vestibular neurons in rhombomeres 5-7 of larval zebrafish. First, we found that neurons within this central population project preferentially to motoneurons that move the eyes downward. Concordantly, when the entire population of asymmetrically projecting neurons was stimulated collectively, only downward eye rotations were observed, demonstrating a functional correlate of the anatomical bias. When these neurons are ablated, fish failed to rotate their eyes following either nose-up or nose-down body tilts. This asymmetrically projecting central population thus participates in both upward and downward gaze stabilization. In addition to projecting to motoneurons, central vestibular neurons also receive direct sensory input from peripheral afferents. To infer whether asymmetric projections can facilitate sensory encoding or motor output, we modeled differentially projecting sets of central vestibular neurons. Whereas motor command strength was independent of projection allocation, asymmetric projections enabled more accurate representation of nose-up stimuli. The model shows how asymmetric connectivity could enhance the representation of imbalance during nose-up postures while preserving gaze stabilization performance. Finally, we found that central vestibular neurons were necessary for a vital behavior requiring maintenance of a nose-up posture: swim bladder inflation. These observations suggest that asymmetric connectivity in the vestibular system facilitates representation of ethologically relevant stimuli without

Word selection affects perceptions of synthetic biology

Directory of Open Access Journals (Sweden)

Tonidandel Scott

2011-07-01

Full Text Available Abstract Members of the synthetic biology community have discussed the significance of word selection when describing synthetic biology to the general public. In particular, many leaders proposed the word "create" was laden with negative connotations. We found that word choice and framing does affect public perception of synthetic biology. In a controlled experiment, participants perceived synthetic biology more negatively when "create" was used to describe the field compared to "construct" (p = 0.008. Contrary to popular opinion among synthetic biologists, however, low religiosity individuals were more influenced negatively by the framing manipulation than high religiosity people. Our results suggest that synthetic biologists directly influence public perception of their field through avoidance of the word "create".

Experimental research on photovoltaic module for asymmetrical compound parabolic concentrator

Energy Technology Data Exchange (ETDEWEB)

Yuan, Jinshe; Wang, Mingyue [Chongqing Normal University, Chongqing (China). Department of Physics; Yang, Changmin [Xian University of Technology, Xian (China). Department of Applied Physics

2008-07-01

The photovoltaic module for the use of fixed asymmetrical CPC concentrator was designed and fabricated based on the performance of polycrystalline-silicon solar cells with back surface field (BSF) structure. The performance of the combination of the module and asymmetrical CPC concentrator was investigated. The results show its effective concentration ratio to be 2.46 and the output power of the PV-a-CPC system to be increased by 2.13 times compared with that of the module approximately. (orig.)

Synthesis of sheath voltage drops in asymmetric radio-frequency discharges

International Nuclear Information System (INIS)

Yonemura, Shigeru; Nanbu, Kenichi; Iwata, Naoaki

2004-01-01

A sheath voltage drop in asymmetric discharges is one of the most important parameters of radio-frequency capacitively coupled plasmas because it determines the kinetic energy of the ions incident on the target or substrate. In this study, we developed a numerical simulation code to estimate the sheath voltage drops and, consequently, the self-bias voltage. We roughly approximated general asymmetric rf discharges to one-dimensional spherical ones. The results obtained by using our simulation code are consistent with measurements and Lieberman's theory

Asymmetric output profile of Xe Laser

NARCIS (Netherlands)

Blok, F.J.; Rubin, P.L.; Verschuur, Jeroen W.J.; Witteman, W.J.

2001-01-01

A new set of asymmetric modes was recently revealed in a Xe slab laser with pronounced lens effects originating from gas heating in the discharge. The appearance of these modes is a threshold effect. Their domain of existence in the Xe laser is discussed. It is shown that mode competition can result

DIFLUORPHOS and SYNPHOS in asymmetric catalysis: Synthetic ...

Indian Academy of Sciences (India)

ture did not significantly affect the stereochemical out- come. For this process ..... economy concepts.36 In 2012, Zhang, Ratovelomanana-. Vidal and co-workers ..... broad spectrum cancer therapeutic agents.53 To this end, dynamic kinetic ...

Dosimetric characteristics of a 6 MV photon beam from a linear accelerator with asymmetric collimator jaws

International Nuclear Information System (INIS)

Palta, J.R.; Ayyangar, K.M.; Suntharalingam, N.

1988-01-01

Dosimetric measurements have been made of a 6 MV photon beam from a linear accelerator equipped with asymmetric jaws. The field size factors for asymmetrically set fields are compared to those for symmetrically set fields. The change of beam quality has been measured as a function of off-axis position of the asymmetric fields to assess its effect on depth dose. Additional measurements include beam penumbra and shape of isodose curves for open and wedge fields as the field opening is moved asymmetrically from the central ray

Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis

OpenAIRE

Kawaguchi, Daichi; Furutachi, Shohei; Kawai, Hiroki; Hozumi, Katsuto; Gotoh, Yukiko

2013-01-01

Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch...

Catalytic asymmetric synthesis of the alkaloid (+)-myrtine

NARCIS (Netherlands)

Pizzuti, Maria Gabriefla; Minnaard, Adriaan J.; Feringa, Ben L.

2008-01-01

A new protocol for the asymmetric synthesis of trans-2,6-disubstituted-4-piperidones has been developed using a catalytic enantioselective conjugate addition reaction in combination with a diastereoselective lithiation-substitution sequence; an efficient synthesis of (+)-myrtine has been achieved

Comprehensive asymmetric dark matter model

OpenAIRE

Lonsdale, Stephen J.; Volkas, Raymond R.

2018-01-01

Asymmetric dark matter (ADM) is motivated by the similar cosmological mass densities measured for ordinary and dark matter. We present a comprehensive theory for ADM that addresses the mass density similarity, going beyond the usual ADM explanations of similar number densities. It features an explicit matter-antimatter asymmetry generation mechanism, has one fully worked out thermal history and suggestions for other possibilities, and meets all phenomenological, cosmological and astrophysical...

Tourist Demand Reactions: Symmetric or Asymmetric across the Business Cycle?

Science.gov (United States)

Bronner, Fred; de Hoog, Robert

2017-09-01

Economizing and spending priorities on different types of vacations are investigated during two periods: an economic downturn and returning prosperity. Two nation-wide samples of vacationers are used: one during a downturn, the other one at the start of the recovery period. Through comparing the results, conclusions can be drawn about symmetric or asymmetric tourist demand across the business cycle. The main summer holiday has an asymmetric profile: being fairly crisis-resistant during a recession and showing considerable growth during an expansion. This does not apply to short vacations and day trips, each having a symmetric profile: during a recession they experience substantial reductions and during expansion comparable growth. So when talking about tourist demand in general , one cannot say that it is symmetric or asymmetric across the business cycle: it depends on the type of vacation. Differences in tourist demand are best explained by the role of Quality-of-Life for vacationers.

Efficient computation of discounted asymmetric information zero-sum stochastic games

KAUST Repository

Li, Lichun; Shamma, Jeff S.

2015-01-01

In asymmetric information zero-sum games, one player has superior information about the game over the other. Asymmetric information games are particularly relevant for security problems, e.g., where an attacker knows its own skill set or alternatively a system administrator knows the state of its resources. In such settings, the informed player is faced with the tradeoff of exploiting its superior information at the cost of revealing its superior information. This tradeoff is typically addressed through randomization, in an effort to keep the uninformed player informationally off balance. A lingering issue is the explicit computation of such strategies. This paper, building on prior work for repeated games, presents an LP formulation to compute suboptimal strategies for the informed player in discounted asymmetric information stochastic games in which state transitions are not affected by the uninformed player. Furthermore, the paper presents bounds between the security level guaranteed by the sub-optimal strategy and the optimal value. The results are illustrated on a stochastic intrusion detection problem.

Efficient computation of discounted asymmetric information zero-sum stochastic games

KAUST Repository

Li, Lichun

2015-12-15

In asymmetric information zero-sum games, one player has superior information about the game over the other. Asymmetric information games are particularly relevant for security problems, e.g., where an attacker knows its own skill set or alternatively a system administrator knows the state of its resources. In such settings, the informed player is faced with the tradeoff of exploiting its superior information at the cost of revealing its superior information. This tradeoff is typically addressed through randomization, in an effort to keep the uninformed player informationally off balance. A lingering issue is the explicit computation of such strategies. This paper, building on prior work for repeated games, presents an LP formulation to compute suboptimal strategies for the informed player in discounted asymmetric information stochastic games in which state transitions are not affected by the uninformed player. Furthermore, the paper presents bounds between the security level guaranteed by the sub-optimal strategy and the optimal value. The results are illustrated on a stochastic intrusion detection problem.

Asymmetric cell division requires specific mechanisms for adjusting global transcription.

Science.gov (United States)

Mena, Adriana; Medina, Daniel A; García-Martínez, José; Begley, Victoria; Singh, Abhyudai; Chávez, Sebastián; Muñoz-Centeno, Mari C; Pérez-Ortín, José E

2017-12-01

Most cells divide symmetrically into two approximately identical cells. There are many examples, however, of asymmetric cell division that can generate sibling cell size differences. Whereas physical asymmetric division mechanisms and cell fate consequences have been investigated, the specific problem caused by asymmetric division at the transcription level has not yet been addressed. In symmetrically dividing cells the nascent transcription rate increases in parallel to cell volume to compensate it by keeping the actual mRNA synthesis rate constant. This cannot apply to the yeast Saccharomyces cerevisiae, where this mechanism would provoke a never-ending increasing mRNA synthesis rate in smaller daughter cells. We show here that, contrarily to other eukaryotes with symmetric division, budding yeast keeps the nascent transcription rates of its RNA polymerases constant and increases mRNA stability. This control on RNA pol II-dependent transcription rate is obtained by controlling the cellular concentration of this enzyme. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Asymmetric catalysis in the cyclopropanation of olefins; Catalise assimetrica na ciclopropanacao de olefinas

Energy Technology Data Exchange (ETDEWEB)

Leao, Raquel A.C.; Ferreira, Vitor F.; Pinheiro, Sergio [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Quimica Organica]. E-mail: cegvito@vm.uff.br

2007-07-01

The main methodologies in the asymmetric cyclopropanation of alkenes with emphasis on asymmetric catalysis are covered. Examples are the Simmons-Smith reaction, the use of diazoalkanes and reactions carried out by decomposition of alpha-diazoesters in the presence of transition metals. (author)

Smoking synthetic marijuana leads to self-mutilation requiring bilateral amputations.

Science.gov (United States)

Meijer, Karim A; Russo, Russell R; Adhvaryu, Dhaval V

2014-04-01

Synthetic cannabinoids have become a worldwide epidemic because they provide a sometimes legal, easily accessible, and presumably safe alternative to marijuana. Recently published reports have linked acute psychosis, myocardial infarctions, convulsions, self-harm, and even terrorist organizations to these designer substances. This case report outlines the first reported case of Black Diamond, a synthetic cannabis, leading to a self-inflicted burn to the bilateral upper extremities requiring a transradial amputation of the right arm and a toe transfer procedure of the left hand after loss of all digits. The patient presented to the emergency department with self-inflicted fourth-degree burns to the bilateral hands and forearms with second-degree burns of the face, for a total body surface area of 14.5%. The patient was found by firefighters with his hands aflame on his kitchen stove. With no previous medical or psychiatric history and collateral information to confirm the patient's mental status prior to use of Black Diamond, the patient's acute psychotic episode was attributed to Black Diamond. After multiple procedures and a lengthy recovery, the patient completed his post-graduate education and entered the professional world. As orthopedic surgeons, we should be involved in educating the public on the harm of these designer drugs, including self-mutilation. The popularity of synthetic drugs in the United States will continue to present a major challenge to all health care providers. Orthopedists are on the front lines of this epidemic because these drugs push patients into risky, traumatic behavior. Copyright 2014, SLACK Incorporated.

Synthetic Biology for Specialty Chemicals.

Science.gov (United States)

Markham, Kelly A; Alper, Hal S

2015-01-01

In this review, we address recent advances in the field of synthetic biology and describe how those tools have been applied to produce a wide variety of chemicals in microorganisms. Here we classify the expansion of the synthetic biology toolbox into three different categories based on their primary function in strain engineering-for design, for construction, and for optimization. Next, focusing on recent years, we look at how chemicals have been produced using these new synthetic biology tools. Advances in producing fuels are briefly described, followed by a more thorough treatment of commodity chemicals, specialty chemicals, pharmaceuticals, and nutraceuticals. Throughout this review, an emphasis is placed on how synthetic biology tools are applied to strain engineering. Finally, we discuss organism and host strain diversity and provide a future outlook in the field.

Mammalian synthetic biology: emerging medical applications.

Science.gov (United States)

Kis, Zoltán; Pereira, Hugo Sant'Ana; Homma, Takayuki; Pedrigi, Ryan M; Krams, Rob

2015-05-06

In this review, we discuss new emerging medical applications of the rapidly evolving field of mammalian synthetic biology. We start with simple mammalian synthetic biological components and move towards more complex and therapy-oriented gene circuits. A comprehensive list of ON-OFF switches, categorized into transcriptional, post-transcriptional, translational and post-translational, is presented in the first sections. Subsequently, Boolean logic gates, synthetic mammalian oscillators and toggle switches will be described. Several synthetic gene networks are further reviewed in the medical applications section, including cancer therapy gene circuits, immuno-regulatory networks, among others. The final sections focus on the applicability of synthetic gene networks to drug discovery, drug delivery, receptor-activating gene circuits and mammalian biomanufacturing processes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Protease-sensitive synthetic prions.

Directory of Open Access Journals (Sweden)

David W Colby

2010-01-01

Full Text Available Prions arise when the cellular prion protein (PrP(C undergoes a self-propagating conformational change; the resulting infectious conformer is designated PrP(Sc. Frequently, PrP(Sc is protease-resistant but protease-sensitive (s prions have been isolated in humans and other animals. We report here that protease-sensitive, synthetic prions were generated in vitro during polymerization of recombinant (rec PrP into amyloid fibers. In 22 independent experiments, recPrP amyloid preparations, but not recPrP monomers or oligomers, transmitted disease to transgenic mice (n = 164, denoted Tg9949 mice, that overexpress N-terminally truncated PrP. Tg9949 control mice (n = 174 did not spontaneously generate prions although they were prone to late-onset spontaneous neurological dysfunction. When synthetic prion isolates from infected Tg9949 mice were serially transmitted in the same line of mice, they exhibited sPrP(Sc and caused neurodegeneration. Interestingly, these protease-sensitive prions did not shorten the life span of Tg9949 mice despite causing extensive neurodegeneration. We inoculated three synthetic prion isolates into Tg4053 mice that overexpress full-length PrP; Tg4053 mice are not prone to developing spontaneous neurological dysfunction. The synthetic prion isolates caused disease in 600-750 days in Tg4053 mice, which exhibited sPrP(Sc. These novel synthetic prions demonstrate that conformational changes in wild-type PrP can produce mouse prions composed exclusively of sPrP(Sc.

A portion of the Pf155/RESA antigen of Plasmodium falciparum is accessible on the surface of infected erythrocytes

International Nuclear Information System (INIS)

Saul, A.; Maloy, W.L.; Howard, R.J.; Rock, E.P.

1988-01-01

An investigation of antigens accessible to lactoperoxidase-catalysed cell surface iodination on intact Plasmodium falciparum-infected red blood cells (RBC) has identified a 125 I-labelled antigen with an apparent size of about 155 kD. This labelled protein was specifically immunoprecipitated by the following antibodies: a rabbit antiserum and a mouse monoclonal antibody raised against a synthetic peptide comprising the 3',8-mer repeat EENVEHDA of the Pf155/RESA protein; a rabbit antiserum raised against a synthetic octapeptide comprising two copies of the 3',4-mer repeat EENV of the Pf155/RESA protein; and rabbit antisera against another synthetic peptide C(MYSNNNVED) 2 . The last antibody shows a strong reaction in asexual blood state parasites with the Pf155/RESA antigen. While this antigen has been described previously as a submembrane component of the outer membrane of infected RBC, this report shows that at least part of it is accessible to the surface of both ring and late trophozoite-infected erythrocytes. 21 refs., 4 figs

Computational Re-design of Synthetic Genetic Oscillators for Independent Amplitude and Frequency Modulation.

Science.gov (United States)

Tomazou, Marios; Barahona, Mauricio; Polizzi, Karen M; Stan, Guy-Bart

2018-04-25

To perform well in biotechnology applications, synthetic genetic oscillators must be engineered to allow independent modulation of amplitude and period. This need is currently unmet. Here, we demonstrate computationally how two classic genetic oscillators, the dual-feedback oscillator and the repressilator, can be re-designed to provide independent control of amplitude and period and improve tunability-that is, a broad dynamic range of periods and amplitudes accessible through the input "dials." Our approach decouples frequency and amplitude modulation by incorporating an orthogonal "sink module" where the key molecular species are channeled for enzymatic degradation. This sink module maintains fast oscillation cycles while alleviating the translational coupling between the oscillator's transcription factors and output. We characterize the behavior of our re-designed oscillators over a broad range of physiologically reasonable parameters, explain why this facilitates broader function and control, and provide general design principles for building synthetic genetic oscillators that are more precisely controllable. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Aspects of collisionless magnetic reconnection in asymmetric systems

Energy Technology Data Exchange (ETDEWEB)

Hesse, Michael; Aunai, Nicolas; Kuznetsova, Masha [Heliophysics Science Division, Code 670, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Zenitani, Seiji [National Astronomical Observatory of Japan, Tokyo (Japan); Birn, Joachim [Space Science Institute, Boulder, Colorado 80301 (United States)

2013-06-15

Asymmetric reconnection is being investigated by means of particle-in-cell simulations. The research has two foci: the direction of the reconnection line in configurations with nonvanishing magnetic fields; and the question why reconnection can be faster if a guide field is added to an otherwise unchanged asymmetric configuration. We find that reconnection prefers a direction, which maximizes the available magnetic energy, and show that this direction coincides with the bisection of the angle between the asymptotic magnetic fields. Regarding the difference in reconnection rates between planar and guide field models, we demonstrate that a guide field can provide essential confinement for particles in the reconnection region, which the weaker magnetic field in one of the inflow directions cannot necessarily provide.

Aspects of collisionless magnetic reconnection in asymmetric systems

International Nuclear Information System (INIS)

Hesse, Michael; Aunai, Nicolas; Kuznetsova, Masha; Zenitani, Seiji; Birn, Joachim

2013-01-01

Asymmetric reconnection is being investigated by means of particle-in-cell simulations. The research has two foci: the direction of the reconnection line in configurations with nonvanishing magnetic fields; and the question why reconnection can be faster if a guide field is added to an otherwise unchanged asymmetric configuration. We find that reconnection prefers a direction, which maximizes the available magnetic energy, and show that this direction coincides with the bisection of the angle between the asymptotic magnetic fields. Regarding the difference in reconnection rates between planar and guide field models, we demonstrate that a guide field can provide essential confinement for particles in the reconnection region, which the weaker magnetic field in one of the inflow directions cannot necessarily provide

Aspects of Collisionless Magnetic Reconnection in Asymmetric Systems

Science.gov (United States)

Hesse, Michael; Aunai, Nicolas; Zeitani, Seiji; Kuznetsova, Masha; Birn, Joachim

2013-01-01

Asymmetric reconnection is being investigated by means of particle-in-cell simulations. The research has two foci: the direction of the reconnection line in configurations with non-vanishing magnetic fields; and the question why reconnection can be faster if a guide field is added to an otherwise unchanged asymmetric configuration. We find that reconnection prefers a direction, which maximizes the available magnetic energy, and show that this direction coincides with the bisection of the angle between the asymptotic magnetic fields. Regarding the difference in reconnection rates between planar and guide field models, we demonstrate that a guide field can provide essential confinement for particles in the reconnection region, which the weaker magnetic field in one of the inflow directions cannot necessarily provide.

Reduction of Asymmetric Information through Corporate Governance Mechanisms

DEFF Research Database (Denmark)

Holm, Claus; Schøler, Finn

Research Question/Issue: Is the reduction of asymmetric information through Corporate Governance mechanisms more important for some listed companies than for others? The purpose of this study is to examine how differences in "ownership dispersion" and "international orientation" affect the partic......Research Question/Issue: Is the reduction of asymmetric information through Corporate Governance mechanisms more important for some listed companies than for others? The purpose of this study is to examine how differences in "ownership dispersion" and "international orientation" affect...... the particular use of the Corporate Governance mechanisms "transparency" and "board independence" in listed companies. Research Findings/Insights: Our findings are based on a Danish dataset which includes 100 listed companies. We find that transparency is a more important Corporate Governance mechanism...

R & D STRATEGIC INVESTMENT IN AN ASYMMETRICAL CASE

Institute of Scientific and Technical Information of China (English)

Minggao XUE; Pu GONG

2006-01-01

This article analyzes R & D investment decisions in an asymmetrical case. The investment decisions share three important characteristics. First, the investment is completely irreversible. Second,there are two kinds of uncertainties over the future returns from the investment and over technology in R & D process, respectively. Third, there is strategic competition in the asymmetrical case. This article presents the optimal investment threshold values and the optimal investment rule of high-efficient firm (leader), and shows that the investment threshold values are reduced by competition of two firms.Finally, the mixed investment strategies for two firms, the probability that each firm separately exercises the option to invest, and the probability that two firms simultaneously exercise the option are given in the paper.

Synergistic Synthetic Biology: Units in Concert

Science.gov (United States)

Trosset, Jean-Yves; Carbonell, Pablo

2013-01-01

Synthetic biology aims at translating the methods and strategies from engineering into biology in order to streamline the design and construction of biological devices through standardized parts. Modular synthetic biology devices are designed by means of an adequate elimination of cross-talk that makes circuits orthogonal and specific. To that end, synthetic constructs need to be adequately optimized through in silico modeling by choosing the right complement of genetic parts and by experimental tuning through directed evolution and craftsmanship. In this review, we consider an additional and complementary tool available to the synthetic biologist for innovative design and successful construction of desired circuit functionalities: biological synergies. Synergy is a prevalent emergent property in biological systems that arises from the concerted action of multiple factors producing an amplification or cancelation effect compared with individual actions alone. Synergies appear in domains as diverse as those involved in chemical and protein activity, polypharmacology, and metabolic pathway complementarity. In conventional synthetic biology designs, synergistic cross-talk between parts and modules is generally attenuated in order to verify their orthogonality. Synergistic interactions, however, can induce emergent behavior that might prove useful for synthetic biology applications, like in functional circuit design, multi-drug treatment, or in sensing and delivery devices. Synergistic design principles are therefore complementary to those coming from orthogonal design and may provide added value to synthetic biology applications. The appropriate modeling, characterization, and design of synergies between biological parts and units will allow the discovery of yet unforeseeable, novel synthetic biology applications. PMID:25022769

Synergistic Synthetic Biology: Units in Concert

International Nuclear Information System (INIS)

Trosset, Jean-Yves; Carbonell, Pablo

2013-01-01

Synthetic biology aims at translating the methods and strategies from engineering into biology in order to streamline the design and construction of biological devices through standardized parts. Modular synthetic biology devices are designed by means of an adequate elimination of cross-talk that makes circuits orthogonal and specific. To that end, synthetic constructs need to be adequately optimized through in silico modeling by choosing the right complement of genetic parts and by experimental tuning through directed evolution and craftsmanship. In this review, we consider an additional and complementary tool available to the synthetic biologist for innovative design and successful construction of desired circuit functionalities: biological synergies. Synergy is a prevalent emergent property in biological systems that arises from the concerted action of multiple factors producing an amplification or cancelation effect compared with individual actions alone. Synergies appear in domains as diverse as those involved in chemical and protein activity, polypharmacology, and metabolic pathway complementarity. In conventional synthetic biology designs, synergistic cross-talk between parts and modules is generally attenuated in order to verify their orthogonality. Synergistic interactions, however, can induce emergent behavior that might prove useful for synthetic biology applications, like in functional circuit design, multi-drug treatment, or in sensing and delivery devices. Synergistic design principles are therefore complementary to those coming from orthogonal design and may provide added value to synthetic biology applications. The appropriate modeling, characterization, and design of synergies between biological parts and units will allow the discovery of yet unforeseeable, novel synthetic biology applications.

The rationality of EIA forecasts under symmetric and asymmetric loss

International Nuclear Information System (INIS)

Auffhammer, Maximilian

2007-01-01

The United States Energy Information Administration publishes annual forecasts of nationally aggregated energy consumption, production, prices, intensity and GDP. These government issued forecasts often serve as reference cases in the calibration of simulation and econometric models, which climate and energy policy are based on. This study tests for rationality of published EIA forecasts under symmetric and asymmetric loss. We find strong empirical evidence of asymmetric loss for oil, coal and electricity prices as well as natural gas consumption, electricity sales, GDP and energy intensity. (author)

The rationality of EIA forecasts under symmetric and asymmetric loss

Energy Technology Data Exchange (ETDEWEB)

Auffhammer, Maximilian [Department of Agricultural and Resource Economics, University of California, 207 Giannini Hall 3310, Berkeley, CA 94720 (United States)

2007-05-15

The United States Energy Information Administration publishes annual forecasts of nationally aggregated energy consumption, production, prices, intensity and GDP. These government issued forecasts often serve as reference cases in the calibration of simulation and econometric models, which climate and energy policy are based on. This study tests for rationality of published EIA forecasts under symmetric and asymmetric loss. We find strong empirical evidence of asymmetric loss for oil, coal and electricity prices as well as natural gas consumption, electricity sales, GDP and energy intensity. (author)

Synthetic Cannabis Overdose and Withdrawal in a Young Adult: A Case Report, Commentary on Regulation, and Review of the Literature.

Science.gov (United States)

Samaan, John; Ferrer, Gerardo F; Akinyemi, Boye; Junquera, Patricia; Oms, Juan; Dumenigo, Rhaisa

2016-01-01

Introduction . Marijuana has been used for its psychotropic effects including enhanced relaxation and perceptual alterations. However, the use of synthetic marijuana (SM) leads to more frequent and drastic side effects than the typical use of regular marijuana, owing to the fact that SM has a shorter duration and an earlier peak of action. Despite all the potential adverse health effects associated with SM use, current health policies on SM are very limited. It is believed that the popularity of SM has increased, due to its easy accessibility in the US and lack of detection in typical urine drug screens for THC. Case Report . One case presented is of a young adult patient, with histories of recurrent synthetic cannabis and recreational cannabis use, who had developed drastic physiological and psychiatric symptoms, including the development of acute-onset psychosis. Conclusion/Discussion . This case, as many others nationwide, exemplifies the impact of synthetic cannabinoid use and abuse in adolescents. Side effects and adverse health consequences of synthetic cannabinoid use warrant stricter regulations and policies in order to decrease psychiatric hospital admissions and associated healthcare costs.

A mean-field theory on the differential capacitance of asymmetric ionic liquid electrolytes

International Nuclear Information System (INIS)

Han, Yining; Huang, Shanghui; Yan, Tianying

2014-01-01

The size of ions significantly influences the electric double layer structure of room temperature ionic liquid (IL) electrolytes and their differential capacitance (C d ). In this study, we extended the mean-field theory (MFT) developed independently by Kornyshev (2007J. Phys. Chem. B 111 5545–57) and Kilic, Bazant, and Ajdari (2007 Phys. Rev. E 75 021502) (the KKBA MFT) to take into account the asymmetric 1:1 IL electrolytes by introducing an additional parameter ξ for the anion/cation volume ratio, besides the ionic compressibility γ in the KKBA MFT. The MFT of asymmetric ions becomes KKBA MFT upon ξ = 1, and further reduces to Gouy–Chapman theory in the γ → 0 limit. The result of the extended MFT demonstrates that the asymmetric ILs give rise to an asymmetric C d , with the higher peak in C d occurring at positive polarization for the smaller anionic size. At high potential, C d decays asymptotically toward KKBA MFT characterized by γ for the negative polarization, and characterized by ξγ for the positive polarization, with inverse-square-root behavior. At low potential, around the potential of zero charge, the asymmetric ions cause a higher C d , which exceeds that of Gouy–Chapman theory. (paper)

DNA-based asymmetric organometallic catalysis in water

NARCIS (Netherlands)

Oelerich, Jens; Roelfes, Gerard

2013-01-01

Here, the first examples of DNA-based organometallic catalysis in water that give rise to high enantioselectivities are described. Copper complexes of strongly intercalating ligands were found to enable the asymmetric intramolecular cyclopropanation of alpha-diazo-beta-keto sulfones in water. Up to

Mixed gas plasticization phenomena in asymmetric membranes

NARCIS (Netherlands)

Visser, Tymen

2006-01-01

This thesis describes the thorough investigation of mixed gas transport behavior of asymmetric membranes in the separation of feed streams containing plasticizing gases in order to gain more insights into the complicated behavior of plasticization. To successfully employ gas separation membranes in

A general model for metabolic scaling in self-similar asymmetric networks.

Directory of Open Access Journals (Sweden)

Alexander Byers Brummer

2017-03-01

Full Text Available How a particular attribute of an organism changes or scales with its body size is known as an allometry. Biological allometries, such as metabolic scaling, have been hypothesized to result from selection to maximize how vascular networks fill space yet minimize internal transport distances and resistances. The West, Brown, Enquist (WBE model argues that these two principles (space-filling and energy minimization are (i general principles underlying the evolution of the diversity of biological networks across plants and animals and (ii can be used to predict how the resulting geometry of biological networks then governs their allometric scaling. Perhaps the most central biological allometry is how metabolic rate scales with body size. A core assumption of the WBE model is that networks are symmetric with respect to their geometric properties. That is, any two given branches within the same generation in the network are assumed to have identical lengths and radii. However, biological networks are rarely if ever symmetric. An open question is: Does incorporating asymmetric branching change or influence the predictions of the WBE model? We derive a general network model that relaxes the symmetric assumption and define two classes of asymmetrically bifurcating networks. We show that asymmetric branching can be incorporated into the WBE model. This asymmetric version of the WBE model results in several theoretical predictions for the structure, physiology, and metabolism of organisms, specifically in the case for the cardiovascular system. We show how network asymmetry can now be incorporated in the many allometric scaling relationships via total network volume. Most importantly, we show that the 3/4 metabolic scaling exponent from Kleiber's Law can still be attained within many asymmetric networks.

Asymmetric rotor-like probes to polarized fluorescence study of the macroscopically oriented uniaxial media: Model parameters recognition

International Nuclear Information System (INIS)

Buczkowski, M.; Fisz, J.J.

2008-01-01

In this paper the possibility of the numerical data modelling in the case of angle- and time-resolved fluorescence spectroscopy is investigated. The asymmetric fluorescence probes are assumed to undergo the restricted rotational diffusion in a hosting medium. This process is described quantitatively by the diffusion tensor and the aligning potential. The evolution of the system is expressed in terms of the Smoluchowski equation with an appropriate time-developing operator. A matrix representation of this operator is calculated, then symmetrized and diagonalized. The resulting propagator is used to generate the synthetic noisy data set that imitates results of experimental measurements. The data set serves as a groundwork to the χ 2 optimization, performed by the genetic algorithm followed by the gradient search, in order to recover model parameters, which are diagonal elements of the diffusion tensor, aligning potential expansion coefficients and directions of the electronic dipole moments. This whole procedure properly identifies model parameters, showing that the outlined formalism should be taken in the account in the case of analysing real experimental data

Control theory meets synthetic biology.

Science.gov (United States)

Del Vecchio, Domitilla; Dy, Aaron J; Qian, Yili

2016-07-01

The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology. © 2016 The Author(s).

Synthetic biology, metaphors and responsibility.

Science.gov (United States)

McLeod, Carmen; Nerlich, Brigitte

2017-08-29

Metaphors are not just decorative rhetorical devices that make speech pretty. They are fundamental tools for thinking about the world and acting on the world. The language we use to make a better world matters; words matter; metaphors matter. Words have consequences - ethical, social and legal ones, as well as political and economic ones. They need to be used 'responsibly'. They also need to be studied carefully - this is what we want to do through this editorial and the related thematic collection. In the context of synthetic biology, natural and social scientists have become increasingly interested in metaphors, a wave of interest that we want to exploit and amplify. We want to build on emerging articles and books on synthetic biology, metaphors of life and the ethical and moral implications of such metaphors. This editorial provides a brief introduction to synthetic biology and responsible innovation, as well as a comprehensive review of literature on the social, cultural and ethical impacts of metaphor use in genomics and synthetic biology. Our aim is to stimulate an interdisciplinary and international discussion on the impact that metaphors can have on science, policy and publics in the context of synthetic biology.

Approaches to chemical synthetic biology.

Science.gov (United States)

Chiarabelli, Cristiano; Stano, Pasquale; Anella, Fabrizio; Carrara, Paolo; Luisi, Pier Luigi

2012-07-16

Synthetic biology is first represented in terms of two complementary aspects, the bio-engineering one, based on the genetic manipulation of extant microbial forms in order to obtain forms of life which do not exist in nature; and the chemical synthetic biology, an approach mostly based on chemical manipulation for the laboratory synthesis of biological structures that do not exist in nature. The paper is mostly devoted to shortly review chemical synthetic biology projects currently carried out in our laboratory. In particular, we describe: the minimal cell project, then the "Never Born Proteins" and lastly the Never Born RNAs. We describe and critically analyze the main results, emphasizing the possible relevance of chemical synthetic biology for the progress in basic science and biotechnology. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Computer simulation of molecular absorption spectra for asymmetric top molecules

International Nuclear Information System (INIS)

Bende, A.; Tosa, V.; Cosma, V.

2001-01-01

The effective Hamiltonian formalism has been used to develop a model for infrared multiple-photon absorption (IRMPA) process in asymmetric top molecules. Assuming a collisionless regime, the interaction between the molecule and laser field can be described by the time-dependent Schroedinger equation. By using the rotating wave approximation and Laplace transformation, the time-dependent problem reduces to a time-independent eigen problem for an effective Hamiltonian which can be solved only numerically for a real vibrational-rotational structure of polyatomic molecule. The vibrational-rotational structure is assumed to be an anharmonic oscillator coupled to an asymmetric rigid rotor. The main assumptions taken into account for this model are the following: (1) the excitation is coherent, i.e. the collision (if present during the laser pulse) does not influence the excitation; (2) the excitation starts from the ground state and is near resonant to a normal mode, thus, the rotating wave approximation can be applied; (3) after absorbing N photons the vibrational energy of the excited mode leak into a quasicontinuum; (4) the thermal population of the ground state is given by the Maxwell-Boltzmann distribution law. The energy levels of the asymmetric top molecules cannot be represented by an explicit formula analogous to that for the symmetric top, according to quantum mechanics, but we can consider it a deviation from the prolate or oblate case of the symmetric top, and we can find in the same manner the selection rules of the asymmetric case using the selection rules for the symmetric case. The infrared bands of asymmetric top molecules are not resolved, but if the dispersion used is not too small, so that the envelopes of the bands can be distinguished from simple maxima, it is possible to draw conclusions as to the type of the bands. In this case, the simulation of the absorption spectra can give us some important information about the types of these bands. In

All conducting polymer electrodes for asymmetric solid-state supercapacitors

KAUST Repository

Kurra, Narendra

2015-02-16

In this study, we report the fabrication of solid-state asymmetric supercapacitors (ASCs) based on conducting polymer electrodes on a plastic substrate. Nanostructured conducting polymers of poly(3,4-ethylenedioxythiophene), PEDOT, and polyaniline (PANI) are deposited electrochemically over Au-coated polyethylene naphthalate (PEN) plastic substrates. Due to the electron donating nature of the oxygen groups in the PEDOT, reduction potentials are higher, allowing it to be used as a negative electrode material. In addition, the high stability of PEDOT in its oxidised state makes it capable to exhibit electrochemical activity in a wide potential window. This can qualify PEDOT to be used as a negative electrode in fabricating asymmetric solid state supercapacitors with PANI as a positive electrode while employing polyvinyl alcohol (PVA)/H2SO4 gel electrolyte. The ASCs exhibit a maximum power density of 2.8 W cm−3 at an energy density of 9 mW h cm−3, which is superior to the carbonaceous and metal oxide based ASC solid state devices. Furthermore, the tandem configuration of asymmetric supercapacitors is shown to be capable of powering a red light emitting diode for about 1 minute after charging for 10 seconds.

Symmetric and asymmetric nuclear matter in the relativistic approach

International Nuclear Information System (INIS)

Huber, H.; Weber, F.; Weigel, M.K.

1995-01-01

Symmetric and asymmetric nuclear matter is studied in the framework of the relativistic Brueckner-Hartree-Fock and in the relativistic version of the so-called Λ 00 approximation. The equations are solved self-consistently in the full Dirac space, so avoiding the ambiguities in the choice of the effective scattering amplitude in matter. The calculations were performed for some modern meson-exchange potentials constructed by Brockmann and Machleidt. In some cases we used also the Groningen potentials. First, we examine the outcome for symmetric matter with respect to other calculations, which restrict themselves to positive-energy states only. The main part is devoted to the properties of asymmetric matter. In this case we obtain additionally to the good agreement with the parameters of symmetric matter, also a quite satisfactory agreement with the semiempirical macroscopic coefficients of asymmetric matter. Furthermore, we tested the assumption of a quadratic dependence of the asymmetry energy for a large range of asymmetries. Included is also the dependence of nucleon self-energies on density and neutron excess. For the purpose of comparison we discuss further the similarities and differences with relativistic Hartree and Hartree-Fock calculations and nonrelativistic Skyrme calculations

Advanced materials for aqueous supercapacitors in the asymmetric design

Directory of Open Access Journals (Sweden)

Muniyandi Rajkumar

2015-12-01

Full Text Available Supercapacitors have been recognized as one of the promising energy storage devices in the future energy technology. In this perspective, rapid progress is made in the development of fundamental and applied aspects of supercapacitors. Various techniques have been developed specifically to estimate the specific capacitance. Numerous efforts have been made in the literature to increase the specific capacitance of electrode materials. Recently, researchers pay more attention on designing supercapacitors of asymmetric type with extending cell voltage and dissimilar materials with complementary working potentials. Researchers try to increase the specific energy of asymmetric supercapacitors (ASCs. Conversely, it is still a challenge to find a suitable operation conditions for ASCs in various designs, especially for the one with battery type electrode. In this review, we describe our recent research works and other reports on the preparation of various nanostructured electrode materials and the performances of both symmetric and asymmetric supercapacitors. Finally, we demonstrate effects of charge balance on the capacitive performances of ASCs which consist of one electrode material of the battery type and one capacitive material. We also demonstrate how to evaluate the charge capacities of both positive and negative electrode materials for this ASC application.

Chemoenzymatic synthesis of chiral 2,2'-bipyridine ligands and their N-oxide derivatives: applications in the asymmetric aminolysis of epoxides and asymmetric allylation of aldehydes.

Science.gov (United States)

Boyd, D R; Sharma, N D; Sbircea, L; Murphy, D; Malone, J F; James, S L; Allen, C C R; Hamilton, J T G

2010-03-07

A series of enantiopure 2,2'-bipyridines have been synthesised from the corresponding cis-dihydrodiol metabolites of 2-chloroquinolines. Several of the resulting hydroxylated 2,2'-bipyridines were found to be useful chiral ligands for the asymmetric aminolysis of meso-epoxides leading to the formation of enantioenriched amino alcohols (-->84% ee). N-oxide and N,N'-dioxide derivatives of these 2,2'-bipyridines, including separable atropisomers, have been synthesised and used as enantioselective organocatalysts in the asymmetric allylation of aldehydes to give allylic alcohols (-->86% ee).

Motion in an Asymmetric Double Well

OpenAIRE

Brizard, Alain J.; Westland, Melissa C.

2016-01-01

The problem of the motion of a particle in an asymmetric double well is solved explicitly in terms of the Weierstrass and Jacobi elliptic functions. While the solution of the orbital motion is expressed simply in terms of the Weierstrass elliptic function, the period of oscillation is more directly expressed in terms of periods of the Jacobi elliptic functions.

Asymmetric Synthesis of Apratoxin E.

Science.gov (United States)

Mao, Zhuo-Ya; Si, Chang-Mei; Liu, Yi-Wen; Dong, Han-Qing; Wei, Bang-Guo; Lin, Guo-Qiang

2016-10-21

An efficient method for asymmetric synthesis of apratoxin E 2 is described in this report. The chiral lactone 8, recycled from the degradation of saponin glycosides, was utilized to prepare the non-peptide fragment 6. In addition to this "from nature to nature" strategy, olefin cross-metathesis (CM) was applied as an alternative approach for the formation of the double bond. Moreover, pentafluorophenyl diphenylphosphinate was found to be an efficient condensation reagent for the macrocyclization.

Carrier-envelope phase-stabilized attosecond pulses from asymmetric molecules

International Nuclear Information System (INIS)

Lan Pengfei; Lu Peixiang; Cao Wei; Li Yuhua; Wang Xinlin

2007-01-01

High-order harmonic generation from asymmetric molecules is investigated, and the concept of phase-stabilized infrared ultrashort laser pulses is extended to the extreme ultraviolet regime. It is shown that the ionization symmetry in consecutive half optical cycles is broken for asymmetric molecules, and both even and odd harmonics with comparable intensity are produced. In the time domain, only one attosecond pulse is generated in each cycle of the driving field, and the carrier-envelope phases of the attosecond pulses are equal. Consequently, a clean attosecond pulse train with the same carrier-envelope phase from pulse to pulse is obtained in the extreme ultraviolet regime

Current drive by asymmetrical heating in a toroidal plasma

International Nuclear Information System (INIS)

Gahl, J.M.

1986-01-01

This report describes the first experimental observation of current generation by asymmetrical heating of ions. A unidirectional fast Alfven wave launched by a slow-wave antenna inside the Texas Tech Tokamak, asymmetrically heated the ions. Measurements of the asymmetry of the toroidal plasma current with probes at the top and bottom of the toroidal plasma column confirmed the current generation indirectly. Current generation, obtained in a one-species, hydrogen plasma, is a phenomenon which had not been predicted previously. Calculations of the dispersion relation for the fast Alfven wave near the fundamental cyclotron resonance in a one-species, hydrogen plasma, using warm plasma theory, support the experimental results

Dicer is dispensable for asymmetric RISC loading in mammals.

Science.gov (United States)

Betancur, Juan G; Tomari, Yukihide

2012-01-01

In flies, asymmetric loading of small RNA duplexes into Argonaute2-containing RNA-induced silencing complex (Ago2-RISC) requires Dicer-2/R2D2 heterodimer, which acts as a protein sensor for the thermodynamic stabilities of the ends of small RNA duplexes. However, the mechanism of small RNA asymmetry sensing in mammalian RISC assembly remains obscure. Here, we quantitatively examined RISC assembly and target silencing activity in the presence or absence of Dicer in mammals. Our data show that, unlike the well-characterized fly Ago2-RISC assembly pathway, mammalian Dicer is dispensable for asymmetric RISC loading in vivo and in vitro.

Synthetic Aperture Sequential Beamforming

DEFF Research Database (Denmark)

Kortbek, Jacob; Jensen, Jørgen Arendt; Gammelmark, Kim Løkke

2008-01-01

A synthetic aperture focusing (SAF) technique denoted Synthetic Aperture Sequential Beamforming (SASB) suitable for 2D and 3D imaging is presented. The technique differ from prior art of SAF in the sense that SAF is performed on pre-beamformed data contrary to channel data. The objective is to im......A synthetic aperture focusing (SAF) technique denoted Synthetic Aperture Sequential Beamforming (SASB) suitable for 2D and 3D imaging is presented. The technique differ from prior art of SAF in the sense that SAF is performed on pre-beamformed data contrary to channel data. The objective...... is to improve and obtain a more range independent lateral resolution compared to conventional dynamic receive focusing (DRF) without compromising frame rate. SASB is a two-stage procedure using two separate beamformers. First a set of Bmode image lines using a single focal point in both transmit and receive...... is stored. The second stage applies the focused image lines from the first stage as input data. The SASB method has been investigated using simulations in Field II and by off-line processing of data acquired with a commercial scanner. The performance of SASB with a static image object is compared with DRF...

Towards a synthetic chloroplast.

Directory of Open Access Journals (Sweden)

Christina M Agapakis

2011-04-01

Full Text Available The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner.We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages.Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices.

ASYMMETRIC MAGNETIC RECONNECTION IN WEAKLY IONIZED CHROMOSPHERIC PLASMAS

International Nuclear Information System (INIS)

Murphy, Nicholas A.; Lukin, Vyacheslav S.

2015-01-01

Realistic models of magnetic reconnection in the solar chromosphere must take into account that the plasma is partially ionized and that plasma conditions within any two magnetic flux bundles undergoing reconnection may not be the same. Asymmetric reconnection in the chromosphere may occur when newly emerged flux interacts with pre-existing, overlying flux. We present 2.5D simulations of asymmetric reconnection in weakly ionized, reacting plasmas where the magnetic field strengths, ion and neutral densities, and temperatures are different in each upstream region. The plasma and neutral components are evolved separately to allow non-equilibrium ionization. As in previous simulations of chromospheric reconnection, the current sheet thins to the scale of the neutral–ion mean free path and the ion and neutral outflows are strongly coupled. However, the ion and neutral inflows are asymmetrically decoupled. In cases with magnetic asymmetry, a net flow of neutrals through the current sheet from the weak-field (high-density) upstream region into the strong-field upstream region results from a neutral pressure gradient. Consequently, neutrals dragged along with the outflow are more likely to originate from the weak-field region. The Hall effect leads to the development of a characteristic quadrupole magnetic field modified by asymmetry, but the X-point geometry expected during Hall reconnection does not occur. All simulations show the development of plasmoids after an initial laminar phase

Cosmology in time asymmetric extensions of general relativity

International Nuclear Information System (INIS)

Leon, Genly; Saridakis, Emmanuel N.

2015-01-01

We investigate the cosmological behavior in a universe governed by time asymmetric extensions of general relativity, which is a novel modified gravity based on the addition of new, time-asymmetric, terms on the Hamiltonian framework, in a way that the algebra of constraints and local physics remain unchanged. Nevertheless, at cosmological scales these new terms can have significant effects that can alter the universe evolution, both at early and late times, and the freedom in the choice of the involved modification function makes the scenario able to produce a huge class of cosmological behaviors. For basic ansatzes of modification, we perform a detailed dynamical analysis, extracting the stable late-time solutions. Amongst others, we find that the universe can result in dark-energy dominated, accelerating solutions, even in the absence of an explicit cosmological constant, in which the dark energy can be quintessence-like, phantom-like, or behave as an effective cosmological constant. Moreover, it can result to matter-domination, or to a Big Rip, or experience the sequence from matter to dark energy domination. Additionally, in the case of closed curvature, the universe may experience a cosmological bounce or turnaround, or even cyclic behavior. Finally, these scenarios can easily satisfy the observational and phenomenological requirements. Hence, time asymmetric cosmology can be a good candidate for the description of the universe

The effect of transverse crack upon parametric instability of a rotor-bearing system with an asymmetric disk

Science.gov (United States)

Han, Qinkai; Chu, Fulei

2012-12-01

It is well known that either the asymmetric disk or transverse crack brings parametric inertia (or stiffness) excitation to the rotor-bearing system. When both of them appear in a rotor system, the parametric instability behaviors have not gained sufficient attentions. Thus, the effect of transverse crack upon parametric instability of a rotor-bearing system with an asymmetric disk is studied. First, the finite element equations of motion are established for the asymmetric rotor system. Both the open and breathing transverse cracks are taken into account in the model. Then, the discrete state transition matrix (DSTM) method is introduced for numerically acquiring the instability regions. Based upon these, some computations for a practical asymmetric rotor system with open or breathing transverse crack are conducted, respectively. Variations of the primary and combination instability regions induced by the asymmetric disk with the crack depth are observed, and the effect of the orientation angle between the crack and asymmetric disk on various instability regions are discussed in detail. It is shown that for the asymmetric angle around 0, the existence of transverse (either open or breathing) crack has attenuation effect upon the instability regions. Under certain crack depth, the instability regions could be vanished by the transverse crack. When the asymmetric angle is around π/2, increasing the crack depth would enhance the instability regions.

Surface modification of synthetic clay aimed at biomolecule adsorption: synthesis and characterization

Directory of Open Access Journals (Sweden)

Angela de Mello Ferreira Guimarães

2007-03-01

Full Text Available This work describes the process for functionalization of laponite through the grafting of 3-mercaptopropyltrimethoxysilane (MPTS. Laponite is synthetic smectite clay with surface area of 350 m²/g. The samples, prior to and after functionalization, were characterized by chemical analyses, thermogravimetric analysis (TGA, x ray diffraction (XRD, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT, scanning electron microscopy and energy dispersive spectrometry (MEV/EDS. Infrared spectroscopy and elemental analyses confirmed the presence of organic chains and thiol groups in the modified clay. The immobilized and available thiol group, measured according to the Volhard method, totaled 1.4 meq/g of clay, with approximately 90% accessible for Ag+ trapping. These results represent an improvement as compared to other works concerning the functionalization of smectite-type clays in which the effect produced by functional group blockage limits the access of species to less than 10% of the complexing sites.

Testing for asymmetric pricing in the Canadian retail gasoline market

International Nuclear Information System (INIS)

Godby, R.; Lintner, A.M.; Stengos, T.; Wandschneider, B.

2000-01-01

This paper applies a Threshold Regression model to test for asymmetric pricing in the retail gasoline market in Canada, using weekly data for the period January 1990 to December 1996. We present results for 13 Canadian cities for both premium and regular gasoline. Within the context of an error correction model we test for the presence of asymmetric price behaviour using average changes in crude prices as well as various lags for the change in crude as possible thresholds. We are unable to find any evidence to support this view. 23 refs

Climate agreements under limited participation, asymmetric information and market imperfections

Energy Technology Data Exchange (ETDEWEB)

Hagem, Cathrine

1996-12-31

This thesis relates to climate agreements and cost efficiency by analysing the formation of a system of quota leading to distributed discharge of emissions between countries. Main fields concerned are the greenhouse effect, the political process, efficient and cost-effective climate agreements, and climate agreements under limited participation, asymmetric information and market imperfections covering fields like limited participation in climate agreements, limited participation and indirect impact on non-participating countries` emissions, limited participation and direct impact on non-participating countries` emissions under asymmetric information, and non-competitive market for tradeable quotas. 166 refs., 7 tabs.

Pseudo-Goldstone modes in isospin-asymmetric nuclear matter

International Nuclear Information System (INIS)

Cohen, T.D.; Broniowski, W.

1995-01-01

The authors analyze the chiral limit in dense isospin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter

Synthetic Biology: Advancing Biological Frontiers by Building Synthetic Systems

OpenAIRE

Chen, Yvonne Yu-Hsuan; Galloway, Kate E; Smolke, Christina D

2012-01-01

Advances in synthetic biology are contributing to diverse research areas, from basic biology to biomanufacturing and disease therapy. We discuss the theoretical foundation, applications, and potential of this emerging field.

Terminal moiety-driven electrical performance of asymmetric small-molecule-based organic solar cells

DEFF Research Database (Denmark)

Huang, Jianhua; Zhang, Shanlin; jiang, Bo

2016-01-01

With respect to the successes from symmetric small molecules, asymmetric ones have recently emerged as an alternative choice. In this paper, we present the synthesis and photovoltaic properties of four asymmetric small molecule donors. The benzo[1,2-b:4,5-b']dithiophene (BDT) end in the asymmetri...

Synthetic biology: an emerging engineering discipline.

Science.gov (United States)

Cheng, Allen A; Lu, Timothy K

2012-01-01

Over the past decade, synthetic biology has emerged as an engineering discipline for biological systems. Compared with other substrates, biology poses a unique set of engineering challenges resulting from an incomplete understanding of natural biological systems and tools for manipulating them. To address these challenges, synthetic biology is advancing from developing proof-of-concept designs to focusing on core platforms for rational and high-throughput biological engineering. These platforms span the entire biological design cycle, including DNA construction, parts libraries, computational design tools, and interfaces for manipulating and probing synthetic circuits. The development of these enabling technologies requires an engineering mindset to be applied to biology, with an emphasis on generalizable techniques in addition to application-specific designs. This review aims to discuss the progress and challenges in synthetic biology and to illustrate areas where synthetic biology may impact biomedical engineering and human health.

Reactive solute transport in an asymmetrical fracture-rock matrix system

Science.gov (United States)

Zhou, Renjie; Zhan, Hongbin

2018-02-01

The understanding of reactive solute transport in a single fracture-rock matrix system is the foundation of studying transport behavior in the complex fractured porous media. When transport properties are asymmetrically distributed in the adjacent rock matrixes, reactive solute transport has to be considered as a coupled three-domain problem, which is more complex than the symmetric case with identical transport properties in the adjacent rock matrixes. This study deals with the transport problem in a single fracture-rock matrix system with asymmetrical distribution of transport properties in the rock matrixes. Mathematical models are developed for such a problem under the first-type and the third-type boundary conditions to analyze the spatio-temporal concentration and mass distribution in the fracture and rock matrix with the help of Laplace transform technique and de Hoog numerical inverse Laplace algorithm. The newly acquired solutions are then tested extensively against previous analytical and numerical solutions and are proven to be robust and accurate. Furthermore, a water flushing phase is imposed on the left boundary of system after a certain time. The diffusive mass exchange along the fracture/rock matrixes interfaces and the relative masses stored in each of three domains (fracture, upper rock matrix, and lower rock matrix) after the water flushing provide great insights of transport with asymmetric distribution of transport properties. This study has the following findings: 1) Asymmetric distribution of transport properties imposes greater controls on solute transport in the rock matrixes. However, transport in the fracture is mildly influenced. 2) The mass stored in the fracture responses quickly to water flushing, while the mass stored in the rock matrix is much less sensitive to the water flushing. 3) The diffusive mass exchange during the water flushing phase has similar patterns under symmetric and asymmetric cases. 4) The characteristic distance

Synthetic peptides for antibody production

NARCIS (Netherlands)

N.D. Zegers (Netty)

1995-01-01

textabstractSynthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps

S4. ASYMMETRIC DRUG-INDUCED PARKINSONISM IS RELATED TO PSYCHOPATHOLOGY

Science.gov (United States)

Pieters, Lydia; Bakker, P Roberto; Van Harten, Peter N

2018-01-01

Abstract Background Drug-Induced Parkinsonism (DIP) is the most common movement disorder induced by antipsychotics. The prevalence of DIP in chronic psychiatric populations ranges between 17 and 72% (1–3). Although, DIP is mostly symmetric, asymmetric DIP is reported in 18 to 54% of the patients. (4). There are no studies to the clinical relevance of asymmetric DIP. We investigated the prevalence of motor asymmetry in DIP and its relationship to the severity of psychopathology in a prospective study. Methods In a cohort study of 207 long-stay psychiatric inpatients the prevalence of DIP was assessed at least two times (mean follow-up 1.1 year) in each patient (5). DIP was assessed with the Unified Parkinson Disease Rating Scale (UPDRS) and the prevalence of persistent DIP was 56.2%. Patients with at least one time parkinsonism in the upper/lower limb(s) were included for analyses. Asymmetry of parkinsonism was calculated with the symmetry index (Figure 1). A cut-off value of ≥ 0,20 was used for the definition of asymmetric DIP. Multilevel mixed models were built to explore the relationship between asymmetry in DIP and the severity of psychopathology, measured on the Clinical Global Impression-Schizophrenia scale severity index (CGI-SCH SI). Results In a cohort study of 207 long-stay psychiatric inpatients the prevalence of DIP was assessed at least two times (mean follow-up 1.1 year) in each patient (5). DIP was assessed with the Unified Parkinson Disease Rating Scale (UPDRS) and the prevalence of persistent DIP was 56.2%. Patients with at least one time parkinsonism in the upper/lower limb(s) were included for analyses. Asymmetry of parkinsonism was calculated with the symmetry index (Figure 1). A cut-off value of ≥ 0,20 was used for the definition of asymmetric DIP. Multilevel mixed models were built to explore the relationship between asymmetry in DIP and the severity of psychopathology, measured on the Clinical Global Impression-Schizophrenia scale

Synthetic LDL as targeted drug delivery vehicle

Science.gov (United States)

Forte, Trudy M [Berkeley, CA; Nikanjam, Mina [Richmond, CA

2012-08-28

The present invention provides a synthetic LDL nanoparticle comprising a lipid moiety and a synthetic chimeric peptide so as to be capable of binding the LDL receptor. The synthetic LDL nanoparticle of the present invention is capable of incorporating and targeting therapeutics to cells expressing the LDL receptor for diseases associated with the expression of the LDL receptor such as central nervous system diseases. The invention further provides methods of using such synthetic LDL nanoparticles.

Programming languages for synthetic biology.

Science.gov (United States)

Umesh, P; Naveen, F; Rao, Chanchala Uma Maheswara; Nair, Achuthsankar S

2010-12-01

In the backdrop of accelerated efforts for creating synthetic organisms, the nature and scope of an ideal programming language for scripting synthetic organism in-silico has been receiving increasing attention. A few programming languages for synthetic biology capable of defining, constructing, networking, editing and delivering genome scale models of cellular processes have been recently attempted. All these represent important points in a spectrum of possibilities. This paper introduces Kera, a state of the art programming language for synthetic biology which is arguably ahead of similar languages or tools such as GEC, Antimony and GenoCAD. Kera is a full-fledged object oriented programming language which is tempered by biopart rule library named Samhita which captures the knowledge regarding the interaction of genome components and catalytic molecules. Prominent feature of the language are demonstrated through a toy example and the road map for the future development of Kera is also presented.

Synthetic biology as red herring.

Science.gov (United States)

Preston, Beth

2013-12-01

It has become commonplace to say that with the advent of technologies like synthetic biology the line between artifacts and living organisms, policed by metaphysicians since antiquity, is beginning to blur. But that line began to blur 10,000 years ago when plants and animals were first domesticated; and has been thoroughly blurred at least since agriculture became the dominant human subsistence pattern many millennia ago. Synthetic biology is ultimately only a late and unexceptional offshoot of this prehistoric development. From this perspective, then, synthetic biology is a red herring, distracting us from more thorough philosophical consideration of the most truly revolutionary human practice-agriculture. In the first section of this paper I will make this case with regard to ontology, arguing that synthetic biology crosses no ontological lines that were not crossed already in the Neolithic. In the second section I will construct a parallel case with regard to cognition, arguing that synthetic biology as biological engineering represents no cognitive advance over what was required for domestication and the new agricultural subsistence pattern it grounds. In the final section I will make the case with regard to human existence, arguing that synthetic biology, even if wildly successful, is not in a position to cause significant existential change in what it is to be human over and above the massive existential change caused by the transition to agriculture. I conclude that a longer historical perspective casts new light on some important issues in philosophy of technology and environmental philosophy. Copyright © 2013 Elsevier Ltd. All rights reserved.

US Competitiveness in Synthetic Biology.

Science.gov (United States)

Gronvall, Gigi Kwik

2015-01-01

Synthetic biology is an emerging technical field that aims to make biology easier to engineer; the field has applications in strategically important sectors for the US economy. While the United States currently leads in synthetic biology R&D, other nations are heavily investing in order to boost their economies, which will inevitably diminish the US leadership position. This outcome is not entirely negative--additional investments will expand markets--but it is critical that the US government take steps to remain competitive: There are applications from which the US population and economy may benefit; there are specific applications with importance for national defense; and US technical leadership will ensure that US experts have a leading role in synthetic biology governance, regulation, and oversight. Measures to increase competitiveness in S&T generally are broadly applicable for synthetic biology and should be pursued. However, the US government will also need to take action on fundamental issues that will affect the field's development, such as countering anti-GMO (genetically modified organism) sentiments and anti-GMO legislation. The United States should maintain its regulatory approach so that it is the product that is regulated, not the method used to create a product. At the same time, the United States needs to ensure that the regulatory framework is updated so that synthetic biology products do not fall into regulatory gaps. Finally, the United States needs to pay close attention to how synthetic biology applications may be governed internationally, such as through the Nagoya Protocol of the Convention on Biological Diversity, so that beneficial applications may be realized.

Synthetic Biology: Mapping the Scientific Landscape

Science.gov (United States)

Oldham, Paul; Hall, Stephen; Burton, Geoff

2012-01-01

This article uses data from Thomson Reuters Web of Science to map and analyse the scientific landscape for synthetic biology. The article draws on recent advances in data visualisation and analytics with the aim of informing upcoming international policy debates on the governance of synthetic biology by the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) of the United Nations Convention on Biological Diversity. We use mapping techniques to identify how synthetic biology can best be understood and the range of institutions, researchers and funding agencies involved. Debates under the Convention are likely to focus on a possible moratorium on the field release of synthetic organisms, cells or genomes. Based on the empirical evidence we propose that guidance could be provided to funding agencies to respect the letter and spirit of the Convention on Biological Diversity in making research investments. Building on the recommendations of the United States Presidential Commission for the Study of Bioethical Issues we demonstrate that it is possible to promote independent and transparent monitoring of developments in synthetic biology using modern information tools. In particular, public and policy understanding and engagement with synthetic biology can be enhanced through the use of online interactive tools. As a step forward in this process we make existing data on the scientific literature on synthetic biology available in an online interactive workbook so that researchers, policy makers and civil society can explore the data and draw conclusions for themselves. PMID:22539946

Intercomparison of wedge factor for symmetric field and asymmetric field used 6MV linac

International Nuclear Information System (INIS)

Ji, Youn Sang; Han, Jae Jin

1999-01-01

Therapy equipment have taken progress for Cancer make use of Radiation for the normal tissue system make much of important for shielding. In modern times independent jaw setting to used equipment as possible make use of asymmetric field. Therefore, the asymmetric field be leave out of consideration wedge factor because of with used wedge for the most of part. These experimentation find out have an effect on the dosimetry of out put compared with of the difference between the symmetric field and asymmetric field for the wedge factor

Cilia are required for asymmetric nodal induction in the sea urchin embryo.

Science.gov (United States)

Tisler, Matthias; Wetzel, Franziska; Mantino, Sabrina; Kremnyov, Stanislav; Thumberger, Thomas; Schweickert, Axel; Blum, Martin; Vick, Philipp

2016-08-23

Left-right (LR) organ asymmetries are a common feature of metazoan animals. In many cases, laterality is established by a conserved asymmetric Nodal signaling cascade during embryogenesis. In most vertebrates, asymmetric nodal induction results from a cilia-driven leftward fluid flow at the left-right organizer (LRO), a ciliated epithelium present during gastrula/neurula stages. Conservation of LRO and flow beyond the vertebrates has not been reported yet. Here we study sea urchin embryos, which use nodal to establish larval LR asymmetry as well. Cilia were found in the archenteron of embryos undergoing gastrulation. Expression of foxj1 and dnah9 suggested that archenteron cilia were motile. Cilia were polarized to the posterior pole of cells, a prerequisite of directed flow. High-speed videography revealed rotating cilia in the archenteron slightly before asymmetric nodal induction. Removal of cilia through brief high salt treatments resulted in aberrant patterns of nodal expression. Our data demonstrate that cilia - like in vertebrates - are required for asymmetric nodal induction in sea urchin embryos. Based on these results we argue that the anterior archenteron represents a bona fide LRO and propose that cilia-based symmetry breakage is a synapomorphy of the deuterostomes.

Synthetic peptides for antibody production

NARCIS (Netherlands)

Zegers, N.D.

1995-01-01

Synthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps that lead to the

The Ethics of Synthetic Biology

DEFF Research Database (Denmark)

Christiansen, Andreas

The dissertation analyses and discusses a number of ethical issues that have been raised in connection with the development of synthetic biology. Synthetic biology is a set of new techniques for DNA-level design and construction of living beings with useful properties. The dissertation especially...

Optimal File-Distribution in Heterogeneous and Asymmetric Storage Networks

Science.gov (United States)

Langner, Tobias; Schindelhauer, Christian; Souza, Alexander

We consider an optimisation problem which is motivated from storage virtualisation in the Internet. While storage networks make use of dedicated hardware to provide homogeneous bandwidth between servers and clients, in the Internet, connections between storage servers and clients are heterogeneous and often asymmetric with respect to upload and download. Thus, for a large file, the question arises how it should be fragmented and distributed among the servers to grant "optimal" access to the contents. We concentrate on the transfer time of a file, which is the time needed for one upload and a sequence of n downloads, using a set of m servers with heterogeneous bandwidths. We assume that fragments of the file can be transferred in parallel to and from multiple servers. This model yields a distribution problem that examines the question of how these fragments should be distributed onto those servers in order to minimise the transfer time. We present an algorithm, called FlowScaling, that finds an optimal solution within running time {O}(m log m). We formulate the distribution problem as a maximum flow problem, which involves a function that states whether a solution with a given transfer time bound exists. This function is then used with a scaling argument to determine an optimal solution within the claimed time complexity.

Dynamics of asymmetric kinetic Ising systems revisited

International Nuclear Information System (INIS)

Huang, Haiping; Kabashima, Yoshiyuki

2014-01-01

The dynamics of an asymmetric kinetic Ising model is studied. Two schemes for improving the existing mean-field description are proposed. In the first scheme, we derive the formulas for instantaneous magnetization, equal-time correlation, and time-delayed correlation, considering the correlation between different local fields. To derive the time-delayed correlation, we emphasize that the small-correlation assumption adopted in previous work (Mézard and Sakellariou, 2011 J. Stat. Mech. L07001) is in fact not required. To confirm the prediction efficiency of our method, we perform extensive simulations on single instances with either temporally constant external driving fields or sinusoidal external fields. In the second scheme, we develop an improved mean-field theory for instantaneous magnetization prediction utilizing the notion of the cavity system in conjunction with a perturbative expansion approach. Its efficiency is numerically confirmed by comparison with the existing mean-field theory when partially asymmetric couplings are present. (paper)

On the Collisionless Asymmetric Magnetic Reconnection Rate

Science.gov (United States)

Liu, Yi-Hsin; Hesse, M.; Cassak, P. A.; Shay, M. A.; Wang, S.; Chen, L.-J.

2018-04-01

A prediction of the steady state reconnection electric field in asymmetric reconnection is obtained by maximizing the reconnection rate as a function of the opening angle made by the upstream magnetic field on the weak magnetic field (magnetosheath) side. The prediction is within a factor of 2 of the widely examined asymmetric reconnection model (Cassak & Shay, 2007, https://doi.org/10.1063/1.2795630) in the collisionless limit, and they scale the same over a wide parameter regime. The previous model had the effective aspect ratio of the diffusion region as a free parameter, which simulations and observations suggest is on the order of 0.1, but the present model has no free parameters. In conjunction with the symmetric case (Liu et al., 2017, https://doi.org/10.1103/PhysRevLett.118.085101), this work further suggests that this nearly universal number 0.1, essentially the normalized fast-reconnection rate, is a geometrical factor arising from maximizing the reconnection rate within magnetohydrodynamic-scale constraints.

Vertical Control and Parallel Trade under Asymmetric Information

Directory of Open Access Journals (Sweden)

Alessandro Avenali

2015-05-01

profits from the manufacturer to the wholesaler. Therefore, in R&D-intensive industries, such as pharmaceuticals, policy makers should anticipate the likely consequences of PT under asymmetric information on the long-run incentives to innovate.

Content metamorphosis in synthetic holography

International Nuclear Information System (INIS)

Desbiens, Jacques

2013-01-01

A synthetic hologram is an optical system made of hundreds of images amalgamated in a structure of holographic cells. Each of these images represents a point of view on a three-dimensional space which makes us consider synthetic holography as a multiple points of view perspective system. In the composition of a computer graphics scene for a synthetic hologram, the field of view of the holographic image can be divided into several viewing zones. We can attribute these divisions to any object or image feature independently and operate different transformations on image content. In computer generated holography, we tend to consider content variations as a continuous animation much like a short movie. However, by composing sequential variations of image features in relation with spatial divisions, we can build new narrative forms distinct from linear cinematographic narration. When observers move freely and change their viewing positions, they travel from one field of view division to another. In synthetic holography, metamorphoses of image content are within the observer's path. In all imaging Medias, the transformation of image features in synchronisation with the observer's position is a rare occurrence. However, this is a predominant characteristic of synthetic holography. This paper describes some of my experimental works in the development of metamorphic holographic images.

Asymmetric neighborhood functions accelerate ordering process of self-organizing maps

International Nuclear Information System (INIS)

Ota, Kaiichiro; Aoki, Takaaki; Kurata, Koji; Aoyagi, Toshio

2011-01-01

A self-organizing map (SOM) algorithm can generate a topographic map from a high-dimensional stimulus space to a low-dimensional array of units. Because a topographic map preserves neighborhood relationships between the stimuli, the SOM can be applied to certain types of information processing such as data visualization. During the learning process, however, topological defects frequently emerge in the map. The presence of defects tends to drastically slow down the formation of a globally ordered topographic map. To remove such topological defects, it has been reported that an asymmetric neighborhood function is effective, but only in the simple case of mapping one-dimensional stimuli to a chain of units. In this paper, we demonstrate that even when high-dimensional stimuli are used, the asymmetric neighborhood function is effective for both artificial and real-world data. Our results suggest that applying the asymmetric neighborhood function to the SOM algorithm improves the reliability of the algorithm. In addition, it enables processing of complicated, high-dimensional data by using this algorithm.

Asymmetric information and bank runs

OpenAIRE

Gu, Chao

2007-01-01

It is known that sunspots can trigger panic-based bank runs and that the optimal banking contract can tolerate panic-based runs. The existing literature assumes that these sunspots are based on a publicly observed extrinsic randomizing device. In this paper, I extend the analysis of panic-based runs to include an asymmetric-information, extrinsic randomizing device. Depositors observe different, but correlated, signals on the stability of the bank. I find that if the signals that depositors o...

Asymmetric information and macroeconomic dynamics

Science.gov (United States)

Hawkins, Raymond J.; Aoki, Masanao; Roy Frieden, B.

2010-09-01

We show how macroeconomic dynamics can be derived from asymmetric information. As an illustration of the utility of this approach we derive the equilibrium density, non-equilibrium densities and the equation of motion for the response to a demand shock for productivity in a simple economy. Novel consequences of this approach include a natural incorporation of time dependence into macroeconomics and a common information-theoretic basis for economics and other fields seeking to link micro-dynamics and macro-observables.

Forecasting Performance of Asymmetric GARCH Stock Market Volatility Models

Directory of Open Access Journals (Sweden)

Hojin Lee

2009-12-01

Full Text Available We investigate the asymmetry between positive and negative returns in their effect on conditional variance of the stock market index and incorporate the characteristics to form an out-of-sample volatility forecast. Contrary to prior evidence, however, the results in this paper suggest that no asymmetric GARCH model is superior to basic GARCH(1,1 model. It is our prior knowledge that, for equity returns, it is unlikely that positive and negative shocks have the same impact on the volatility. In order to reflect this intuition, we implement three diagnostic tests for volatility models: the Sign Bias Test, the Negative Size Bias Test, and the Positive Size Bias Test and the tests against the alternatives of QGARCH and GJR-GARCH. The asymmetry test results indicate that the sign and the size of the unexpected return shock do not influence current volatility differently which contradicts our presumption that there are asymmetric effects in the stock market volatility. This result is in line with various diagnostic tests which are designed to determine whether the GARCH(1,1 volatility estimates adequately represent the data. The diagnostic tests in section 2 indicate that the GARCH(1,1 model for weekly KOSPI returns is robust to the misspecification test. We also investigate two representative asymmetric GARCH models, QGARCH and GJR-GARCH model, for our out-of-sample forecasting performance. The out-of-sample forecasting ability test reveals that no single model is clearly outperforming. It is seen that the GJR-GARCH and QGARCH model give mixed results in forecasting ability on all four criteria across all forecast horizons considered. Also, the predictive accuracy test of Diebold and Mariano based on both absolute and squared prediction errors suggest that the forecasts from the linear and asymmetric GARCH models need not be significantly different from each other.

Asymmetric Strecker Synthesis of α-Amino Acids via a Crystallization-Induced Asymmetric Transformation Using (R)-Phenylglycine Amide as Chiral Auxiliary

NARCIS (Netherlands)

Boesten, Wilhelmus H.J.; Seerden, Jean-Paul G.; Lange, Ben de; Dielemans, Hubertus J.A.; Elsenberg, Henk L.M.; Kaptein, Bernard; Moody, Harold M.; Kellogg, Richard M.; Broxterman, Quirinus B.

2001-01-01

Diastereoselective Strecker reactions based on (R)-phenylglycine amide as chiral auxiliary are reported. The Strecker reaction is accompanied by an in situ crystallization-induced asymmetric transformation, whereby one diastereomer selectively precipitates and can be isolated in 76-93% yield and dr

Asymmetric continuum extreme processes in solids and fluids

CERN Document Server

Teisseyre, Roman

2014-01-01

This book deals with a class of basic deformations in asymmetric continuum theory. It describes molecular deformations and transport velocities in fluids, strain deformations in solids as well as the molecular transport, important in fracture processes.

A mono isocentric radiotherapy technique for craniospinal irradiation using asymmetric jaws

International Nuclear Information System (INIS)

Isin, G; Oezyar, E.; Guerdalli, S.; Arslan, G.; Uzal, D.; Atahan, I. L.

1995-01-01

Dose distribution across the junction of matching of craniospinal fields (lateral cranial fields and posterior spinal field) is important as severe complications may result if the beams overlap or disease may recurs if the gapping is too conservative. Various techniques have been used to achieve an effective transverse plane match and half-beam block technique is one of these techniques. Here, we describe a mono isocentric technique for the treatment of craniospinal fields using the asymmetric jaws of our linear accelerator (Philips SL-25). Before the clinical application of this non-standard technique, basic dosimetry parameters are evaluated. Asymmetric collimator dose distributions for various asymmetric field sizes were obtained and compared with symmetric dose distributions for 6 MV x-ray. A computerized 3-D water phantom with a pair of ionization chambers (reference and field) was used for dose profiles, isodose distributions and Percentage Depth Dose (PDD) for various asymmetric field sizes and different off axis distances. The measured values of off axis ratios for the interested depths were used in MU calculations. This new mono isocentric technique provides an ideal dose distribution at match-line as there is no need to move the patient during treatment. Use of heavy secondary cerrobend blocks (beam splitters) is eliminated. This technique provides the ease of consequent daily set-up's and fulfills the requirements for a conformal radiotherapy

Is synthetic biology mechanical biology?

Science.gov (United States)

Holm, Sune

2015-12-01

A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

Access For All

DEFF Research Database (Denmark)

Andersen, Ove Kjeld; Hjulmand, Christian

2005-01-01

Approximately 30% of the Danish population has severe problems in reading everyday text. In the light of the increasing amount of text available on the Internet this poses a democratic challenge to ensure “equal access” to information. The Talking Internet service - Access For All (AFA) - offers...... a free Internet-based tool for reading aloud any marked text with a synthetic voice. The only requirements are a standard equipped PC running a recent Windows OS and an Internet connection. Experiences gathered from running the service for more than 28 months underline the viability of the concept....... There is a clear need for a free internet based Danish text-to-speech synthesizer. Furthermore, the current state of technology i.e. internet bandwidth, response time and server technology is sufficient for setting up an online automatic reading service that is used by steadily growing number of individuals...

Asymmetric Organocatalytic Cycloadditions

DEFF Research Database (Denmark)

Mose, Rasmus

2016-01-01

has gained broad recognition as it has found several applications in academia and industry. The [4+2] cycloaddition has also been performed in an enantioselective aminocatalytic fashion which allows the generation of optically active products. In this thesis it is demonstrated how trienamines can......Since the onset of the new millennium the field of organocatalysis has undergone a great expansion led by investigations in the field of aminocatalysis. This thesis will address some recent developments in aminocatalyzed cycloadditions and provide a theoretical background hereto. Cycloadditions...... undergo cascade reactions with different electron deficient dienophiles in Diels Alder – nucleophilic ring closing reactions. This methodology opens up for the direct asymmetric formation of hydroisochromenes and hydroisoquinolines which may possess interesting biological activities. It is also...

A synthetic system for expression of components of a bacterial microcompartment.

Science.gov (United States)

Sargent, Frank; Davidson, Fordyce A; Kelly, Ciarán L; Binny, Rachelle; Christodoulides, Natasha; Gibson, David; Johansson, Emelie; Kozyrska, Katarzyna; Lado, Lucia Licandro; Maccallum, Jane; Montague, Rachel; Ortmann, Brian; Owen, Richard; Coulthurst, Sarah J; Dupuy, Lionel; Prescott, Alan R; Palmer, Tracy

2013-11-01

In general, prokaryotes are considered to be single-celled organisms that lack internal membrane-bound organelles. However, many bacteria produce proteinaceous microcompartments that serve a similar purpose, i.e. to concentrate specific enzymic reactions together or to shield the wider cytoplasm from toxic metabolic intermediates. In this paper, a synthetic operon encoding the key structural components of a microcompartment was designed based on the genes for the Salmonella propanediol utilization (Pdu) microcompartment. The genes chosen included pduA, -B, -J, -K, -N, -T and -U, and each was shown to produce protein in an Escherichia coli chassis. In parallel, a set of compatible vectors designed to express non-native cargo proteins was also designed and tested. Engineered hexa-His tags allowed isolation of the components of the microcompartments together with co-expressed, untagged, cargo proteins. Finally, an in vivo protease accessibility assay suggested that a PduD-GFP fusion could be protected from proteolysis when co-expressed with the synthetic microcompartment operon. This work gives encouragement that it may be possible to harness the genes encoding a non-native microcompartment for future biotechnological applications.

Synthetic cannabis and acute ischemic stroke.

Science.gov (United States)

Bernson-Leung, Miya E; Leung, Lester Y; Kumar, Sandeep

2014-01-01

An association between marijuana use and stroke has been previously reported. However, the health risks of newer synthetic cannabinoid compounds are less well known. We describe 2 cases that introduce a previously unreported association between synthetic cannabis use and ischemic stroke in young adults. A 22-year-old woman presented with dysarthria, left hemiplegia, and left hemianesthesia within hours of first use of synthetic cannabis. She was healthy and without identified stroke risk factors other than oral contraceptive use and a patent foramen ovale without venous thromboses. A 26-year-old woman presented with nonfluent aphasia, left facial droop, and left hemianesthesia approximately 12 hours after first use of synthetic cannabis. Her other stroke risk factors included migraine with aura, oral contraceptive use, smoking, and a family history of superficial thrombophlebitis. Both women were found to have acute, large-territory infarctions of the right middle cerebral artery. Our 2 cases had risk factors for ischemic stroke but were otherwise young and healthy and the onset of their deficits occurred within hours after first-time exposure to synthetic cannabis. Synthetic cannabis use is an important consideration in the investigation of stroke in young adults. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

The on-line asymmetric traveling salesman problem

NARCIS (Netherlands)

Ausiello, G.; Bonifaci, V.; Laura, L.

2008-01-01

We consider two on-line versions of the asymmetric traveling salesman problem with triangle inequality. For the homing version, in which the salesman is required to return in the city where it started from, we give a -competitive algorithm and prove that this is best possible. For the nomadic

Quantum optics of lossy asymmetric beam splitters

NARCIS (Netherlands)

Uppu, Ravitej; Wolterink, Tom; Tentrup, Tristan Bernhard Horst; Pinkse, Pepijn Willemszoon Harry

2016-01-01

We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2×2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering

Computing modal dispersion characteristics of radially Asymmetric ...

African Journals Online (AJOL)

We developed a matrix theory that applies to with non-circular/circular but concentric layers fibers. And we compute the dispersion characteristics of radially unconventional fiber, known as Asymmetric Bragg fiber. An attempt has been made to determine how the modal characteristics change as circular Bragg fiber is ...

Nitric Oxide Metabolites and Asymmetric Dimethylarginine Concentrations in Breast Milk

Directory of Open Access Journals (Sweden)

Hakan Öztürk

2017-04-01

Full Text Available Objective: Nitric oxide plays a preventive role in the development of necrotizing enterocolitis. Oral nitrite and nitrate intake has gained importance with the discovery of the conversion of nitrite to nitric oxide in acidic medium out of the synthesis of nitric oxide from L-arginine. Objective of this study was to examine the breast milk concentrations of nitric oxide and asymmetric dimethylarginine which is a competitive inhibitor of nitric oxide and to compare these concentrations in terms of gestational age and maturity of breast milk. Study Design: Forty-one women were included in the study. Milk samples were collected from 3 groups of mothers as term, late preterm and preterm on the postpartum days 3, 7 and 28. Results: When breast milk concentrations of nitric oxide were compared according to the postnatal day of the milk independently from gestational age; nitric oxide concentration was higher in the colostrum than in the transition milk and mature milk (p=0,035; p=0,001; respectively. For the comparison of asymmetric dimethylarginine concentrations among these groups and days; no statistically significant difference was observed in terms of gestational age and maturity of the milk (p=0.865, p=0.115; respectively. Conclusion: The highest nitric oxide concentration was found in the colostrum, suggesting that colostrum is a valuable food for newborns. Plasma concentrations of asymmetric dimethylarginine were negatively correlated with nitric oxide and did not show a correlation with breast milk, suggesting that asymmetric dimethylargininedoesn’t make nitric oxide inhibition in breast milk.

Asymmetric Rolling Process Simulations by Dynamic Explicit Crystallographic Homogenized Finite Element Method

International Nuclear Information System (INIS)

Ngoc Tam, Nguyen; Nakamura, Yasunori; Terao, Toshihiro; Kuramae, Hiroyuki; Nakamachi, Eiji; Sakamoto, Hidetoshi; Morimoto, Hideo

2007-01-01

Recently, the asymmetric rolling (ASR) has been applied to the material processing of aluminum alloy sheet to control micro-crystal structure and texture in order to improve the mechanical properties. Previously, several studies aimed at high formability sheet generation have been carried out experimentally, but finite element simulations to predict the deformation induced texture evolution of the asymmetrically rolled sheet metals have not been investigated rigorously. In this study, crystallographic homogenized finite element (FE) codes are developed and applied to analyze the asymmetrical rolling processes. The textures of sheet metals were measured by electron back scattering diffraction (EBSD), and compared with FE simulations. The results from the dynamic explicit type Crystallographic homogenization FEM code shows that this type of simulation is a comprehensive tool to predict the plastic induced texture evolution

Second-order temporal interference of two independent light beams at an asymmetrical beam splitter

International Nuclear Information System (INIS)

Liu Jianbin; Wang Jingjing; Xu Zhuo

2017-01-01

The second-order temporal interference of classical and nonclassical light at an asymmetrical beam splitter is discussed based on two-photon interference in Feynman’s path integral theory. The visibility of the second-order interference pattern is determined by the properties of the superposed light beams, the ratio between the intensities of these two light beams, and the reflectivity of the asymmetrical beam splitter. Some requirements about the asymmetrical beam splitter have to be satisfied in order to ensure that the visibility of the second-order interference pattern of nonclassical light beams exceeds the classical limit. The visibility of the second-order interference pattern of photons emitted by two independent single-photon sources is independent of the ratio between the intensities. These conclusions are important for the researches and applications in quantum optics and quantum information when an asymmetrical beam splitter is employed. (paper)

D mesons in asymmetric nuclear matter

International Nuclear Information System (INIS)

Mishra, Amruta; Mazumdar, Arindam

2009-01-01

We calculate the in-medium D and D meson masses in isospin-asymmetric nuclear matter in an effective chiral model. The D and D mass modifications arising from their interactions with the nucleons and the scalar mesons in the effective hadronic model are seen to be appreciable at high densities and have a strong isospin dependence. These mass modifications can open the channels of the decay of the charmonium states (Ψ ' ,χ c ,J/Ψ) to DD pairs in dense hadronic matter. The isospin asymmetry in the doublet D=(D 0 ,D + ) is seen to be particularly appreciable at high densities and should show in observables such as their production and flow in asymmetric heavy-ion collisions in the compressed baryonic matter experiments in the future facility of FAIR, GSI. The results of the present work are compared to calculations of the D(D) in-medium masses in the literature using the QCD sum rule approach, quark meson coupling model, and coupled channel approach as well as to those from studies of quarkonium dissociation using heavy-quark potentials from lattice QCD at finite temperatures

Engineering the donor selectivity of D-fructose-6-phosphate aldolase for biocatalytic asymmetric cross-aldol additions of glycolaldehyde.

Science.gov (United States)

Szekrenyi, Anna; Soler, Anna; Garrabou, Xavier; Guérard-Hélaine, Christine; Parella, Teodor; Joglar, Jesús; Lemaire, Marielle; Bujons, Jordi; Clapés, Pere

2014-09-22

D-Fructose-6-phosphate aldolase (FSA) is a unique catalyst for asymmetric cross-aldol additions of glycolaldehyde. A combination of a structure-guided approach of saturation mutagenesis, site-directed mutagenesis, and computational modeling was applied to construct a set of FSA variants that improved the catalytic efficiency towards glycolaldehyde dimerization up to 1800-fold. A combination of mutations in positions L107, A129, and A165 provided a toolbox of FSA variants that expand the synthetic possibilities towards the preparation of aldose-like carbohydrate compounds. The new FSA variants were applied as highly efficient catalysts for cross-aldol additions of glycolaldehyde to N-carbobenzyloxyaminoaldehydes to furnish between 80-98 % aldol adduct under optimized reaction conditions. Donor competition experiments showed high selectivity for glycolaldehyde relative to dihydroxyacetone or hydroxyacetone. These results demonstrate the exceptional malleability of the active site in FSA, which can be remodeled to accept a wide spectrum of donor and acceptor substrates with high efficiency and selectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Feasibility study for an asymmetric B-factory at KEK

International Nuclear Information System (INIS)

Ozaki, Hitoshi; Yoshimura, Yoshio

1990-06-01

In June, 1989, the study group for exploring the feasibility of B meson physics using an asymmetric energy accelerator was organized. This report is the summary of the results of the works that this study group carried out in nine months, and is the Japanese edition of the report of English edition 'Task Force Report on Asymmetric B-factory at KEK'. The activity plan of the study group was to make up the plan exceeding the preceding CLEO-2 experiment by utilizing the features of an asymmetric B-factory. Under this plan, the activities have been carried out by the study meetings twice every week on the physics side and once every two weeks on the accelerator side. Besides, in two study meetings held in October and December, 1989, several persons who have engaged in the research on B meson physics actually in foreign countries were invited, and the discussion was carried out. At present toward the materialization of the plan, the concrete investigation of accelerators and measuring instruments was begun. The significance of a B-factory and the construction project, the physics of a B-factory, the experimental method and the plan for an accelerator are reported. (K.I.)

Data analysis of asymmetric structures advanced approaches in computational statistics

CERN Document Server

Saito, Takayuki

2004-01-01

Data Analysis of Asymmetric Structures provides a comprehensive presentation of a variety of models and theories for the analysis of asymmetry and its applications and provides a wealth of new approaches in every section. It meets both the practical and theoretical needs of research professionals across a wide range of disciplines and  considers data analysis in fields such as psychology, sociology, social science, ecology, and marketing. In seven comprehensive chapters this guide details theories, methods, and models for the analysis of asymmetric structures in a variety of disciplines and presents future opportunities and challenges affecting research developments and business applications.

Energy and Data Throughput for Asymmetric Inter-Session Network Coding

DEFF Research Database (Denmark)

Paramanathan, Achuthan; Heide, Janus; Pahlevani, Peyman

2012-01-01

on commercial platforms. The outcome of this paper confirms the analytical expression, and the results shows that even with a large asymmetric data rate there is a gain in terms of energy consumption and throughput when network coding is applied in compare to the case when network coding is not applied.......In this paper we investigate the impact of asymmetric traffic patterns on the energy consumption and throughput in a wireless multi hop network. Network coding is a novel technique for communication systems and a viable solution for wireless multi hop networks. State-of-the-art research is mainly...

Axisymmetric stability of vertically asymmetric tokamaks at large beta poloidal

International Nuclear Information System (INIS)

Yamazaki, K.; Fishman, H.; Okabayashi, M.; Todd, A.M.M.

1981-09-01

The stability of high-β vertically asymmetric tokamak equilibria to rigid displacements is investigated analytically. It is found that vertical stability at large beta poloidal is mainly determined by a coupling between the shape of the plasma surface and the Shafranov shift of the magnetic axis. To the lowest order, symmetric components of the plasma surface shape are found to be the critical destabilizing elements. Asymmetric components have little effect. The inclusion of higher order terms in the high β tokamak expansion leads to further destabilization. Qualitative agreement between these analytic results and numerical stability calculations using the PEST code is demonstrated

Asymmetric inhibition of Ulk2 causes left-right differences in habenular neuropil formation.

Science.gov (United States)

Taylor, Robert W; Qi, Jenny Y; Talaga, Anna K; Ma, Taylur P; Pan, Luyuan; Bartholomew, Clinton R; Klionsky, Daniel J; Moens, Cecilia B; Gamse, Joshua T

2011-07-06

Studies of the zebrafish epithalamus have provided recent insights into the development of left-right brain asymmetry, which is crucial to normal human brain function. The habenular nuclei of zebrafish are robustly asymmetric, with dense elaboration of neuropil only in the left lateral subnucleus. Because this feature is tightly correlated with asymmetric expression of K(+) channel tetramerization domain-containing proteins 12.1 and 12.2 (Kctd12.1/12.2), we screened for Kctd12.1-interacting proteins to identify molecular mechanisms leading to neuropil asymmetry, and uncovered a novel interaction between Kctd12.1 and Unc-51-like kinase 2 (Ulk2). We show here that knockdown of Ulk2 or overexpression of Kctd12 proteins reduces asymmetric neuropil elaboration. Conversely, overexpression of Ulk2 or mutation of kctd12 genes causes excess neuropil elaboration. We conclude that Ulk2 activity promotes neuropil elaboration while Kctd12 proteins limit Ulk2 activity asymmetrically. This work describes a regulatory mechanism for neuronal process extension that may be conserved in other developmental contexts in addition to the epithalamus.

Analysis of axisymmetric shells subjected to asymmetric loads using field consistent shear flexible curved element

Energy Technology Data Exchange (ETDEWEB)

Balakrishna, C; Sarma, B S [Defence Research and Development Laboratory, Hyderabad (India)

1989-02-01

A formulation for axisymmetric shell analysis under asymmetric load based on Fourier series representation and using field consistent 3 noded curved axisymmetric shell element is presented. Different field inconsistent/consistent interpolations for an element based on shear flexible theory have been studied for thick and thin shells under asymmetric loads. Various examples covering axisymmetric as well as asymmetric loading cases have been analyzed and numerical results show a good agreement with the available results in the case of thin shells. 12 refs.

Catalytic asymmetric epoxidation of alpha,beta-unsaturated amides: efficient synthesis of beta-aryl alpha-hydroxy amides using a one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process.

Science.gov (United States)

Nemoto, Tetsuhiro; Kakei, Hiroyuki; Gnanadesikan, Vijay; Tosaki, Shin-Ya; Ohshima, Takashi; Shibasaki, Masakatsu

2002-12-11

The catalytic asymmetric epoxidation of alpha,beta-unsaturated amides using Sm-BINOL-Ph3As=O complex was succeeded. Using 5-10 mol % of the asymmetric catalyst, a variety of amides were epoxidized efficiently, yielding the corresponding alpha,beta-epoxy amides in up to 99% yield and in more than 99% ee. Moreover, the novel one-pot tandem process, one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process, was developed. This method was successfully utilized for the efficient synthesis of beta-aryl alpha-hydroxy amides, including beta-aryllactyl-leucine methyl esters. Interestingly, it was found that beneficial modifications on the Pd catalyst were achieved by the constituents of the first epoxidation, producing a more suitable catalyst for the Pd-catalyzed epoxide opening reaction in terms of chemoselectivity.

Vibration analysis of paper machine's asymmetric tube roll supported by spherical roller bearings

Science.gov (United States)

Heikkinen, Janne E.; Ghalamchi, Behnam; Viitala, Raine; Sopanen, Jussi; Juhanko, Jari; Mikkola, Aki; Kuosmanen, Petri

2018-05-01

This paper presents a simulation method that is used to study subcritical vibrations of a tube roll in a paper machine. This study employs asymmetric 3D beam elements based on the Timoshenko beam theory. An asymmetric beam model accounts for varying stiffness and mass distributions. Additionally, a detailed rolling element bearing model defines the excitations arising from the set of spherical roller bearings at both ends of the rotor. The results obtained from the simulation model are compared against the results from the measurements. The results indicate that the waviness of the bearing rolling surfaces contributes significantly to the subcritical vibrations while the asymmetric properties of the tube roll have only a fractional effect on the studied vibrations.

Improvement of light-current characteristic linearity in a quantum well laser with asymmetric barriers

DEFF Research Database (Denmark)

Zubov, F. I.; Zhukov, A. E.; Shernyakov, Yu M.

2014-01-01

The effect of asymmetric barriers on the light-current characteristic (LCC) of a quantum well laser was studied theoretically and experimentally. It is shown that the utilization of asymmetric barriers in a waveguide prevents the nonlinearity of LCC and, consequently, allows rising of the maximum...

Imaging with Synthetic Aperture Radar

CERN Document Server

Massonnet, Didier

2008-01-01

Describing a field that has been transformed by the recent availability of data from a new generation of space and airborne systems, the authors offer a synthetic geometrical approach to the description of synthetic aperture radar, one that addresses physicists, radar specialists, as well as experts in image processing.  

New chiral ligands in asymmetric catalysis. Application in stabilization of metal nanoparticles

OpenAIRE

Axet Martí, M. Rosa

2006-01-01

Thesis M. Rosa AxetThis thesis deals with the development and application of diphosphite ligands derived from carbohydrates to rhodium-catalysed asymmetric hydroformylation and hydrogenation reactions. The use of various carbohydrate derivative ligands as stabilisers of metal nanoparticles is also studied. The synthesis and the characterisation of the series of diphosphite ligands are described in Chapter 2. The results of the asymmetric hydroformylation of styrene and related vinyl arenes ar...

Pricing and collecting decisions in a closed-loop supply chain with symmetric and asymmetric information

DEFF Research Database (Denmark)

Wei, Jie; Govindan, Kannan; Li, Yongjian

2015-01-01

. The optimal strategies in closed form are given under the decision scenarios with symmetric information; moreover, the first order conditions that the optimal retail price, optimal wholesale price, and optimal collection rate satisfy are given under the decision scenarios with asymmetric information......The optimal decision problem of a closed-loop supply chain with symmetric and asymmetric information structures is considered using game theory in this paper. The paper aims to explore how the manufacturer and the retailer make their own decisions about wholesale price, retail price, and collection...... rate under symmetric and asymmetric information conditions. Four game models are established, which allow one to examine the strategies of each firm and explore the role of the manufacturer and the retailer in four different game scenarios under symmetric and asymmetric information structures...

[Treatment approaches for synthetic drug addiction].

Science.gov (United States)

Kobayashi, Ohji

2015-09-01

In Japan, synthetic drugs have emerged since late 2000s, and cases of emergency visits and fatal traffic accidents due to acute intoxication have rapidly increased. The synthetic drugs gained popularity mainly because they were cheap and thought to be "legal". The Japanese government restricted not only production and distribution, but also its possession and use in April 2014. As the synthetic drug dependent patients have better social profiles compared to methamphetamine abusers, this legal sanction may have triggered the decrease in the number of synthetic drug dependent patient visits observed at Kanagawa Psychiatric Center since July 2014. Treatment of the synthetic drug dependent patients should begin with empathic inquiry into the motives and positive psychological effects of the drug use. In the maintenance phase, training patients to trust others and express their hidden negative emotions through verbal communications is essential. The recovery is a process of understanding the relationship between psychological isolation and drug abuse, and gaining trust in others to cope with negative emotions that the patients inevitably would face in their subsequent lives.

[Synthetic biology and rearrangements of microbial genetic material].

Science.gov (United States)

Liang, Quan-Feng; Wang, Qian; Qi, Qing-Sheng

2011-10-01

As an emerging discipline, synthetic biology has shown great scientific values and application prospects. Although there have been many reviews of various aspects on synthetic biology over the last years, this article, for the first time, attempted to discuss the relationship and difference between microbial genetics and synthetic biology. We summarized the recent development of synthetic biology in rearranging microbial genetic materials, including synthesis, design and reduction of genetic materials, standardization of genetic parts and modularization of genetic circuits. The relationship between synthetic biology and microbial genetic engineering was also discussed in the paper.

Synthetic Cannabis Overdose and Withdrawal in a Young Adult: A Case Report, Commentary on Regulation, and Review of the Literature

Directory of Open Access Journals (Sweden)

John Samaan

2016-01-01

Full Text Available Introduction. Marijuana has been used for its psychotropic effects including enhanced relaxation and perceptual alterations. However, the use of synthetic marijuana (SM leads to more frequent and drastic side effects than the typical use of regular marijuana, owing to the fact that SM has a shorter duration and an earlier peak of action. Despite all the potential adverse health effects associated with SM use, current health policies on SM are very limited. It is believed that the popularity of SM has increased, due to its easy accessibility in the US and lack of detection in typical urine drug screens for THC. Case Report. One case presented is of a young adult patient, with histories of recurrent synthetic cannabis and recreational cannabis use, who had developed drastic physiological and psychiatric symptoms, including the development of acute-onset psychosis. Conclusion/Discussion. This case, as many others nationwide, exemplifies the impact of synthetic cannabinoid use and abuse in adolescents. Side effects and adverse health consequences of synthetic cannabinoid use warrant stricter regulations and policies in order to decrease psychiatric hospital admissions and associated healthcare costs.

A Model of Composite \\textit{B}\\,--\\,\\textit{L} Asymmetric Dark Matter

OpenAIRE

Ibe, Masahiro; Kamada, Ayuki; Kobayashi, Shin; Nakano, Wakutaka

2018-01-01

As the $B-L$ gauge symmetry is the most plausible addition among the various extensions of the Standard Model, it is attractive to identify symmetry which stabilizes dark matter with the $B-L$ gauge symmetry. Besides, dark matter which is stabilized by $B-L$ naturally leads to asymmetric dark matter. In this paper, we construct a model of composite asymmetric dark matter in a bottom-up approach. By assuming that the entropy of the dark sector is released to the Standard Model sector through a...

Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis.

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Kawaguchi, Daichi; Furutachi, Shohei; Kawai, Hiroki; Hozumi, Katsuto; Gotoh, Yukiko

2013-01-01

Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch ligand Delta-like 1 (Dll1) is required to maintain quiescent NSCs in the adult mouse subventricular zone. Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis. Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny. Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

Synthetic Biology and the Translational Imperative.

Science.gov (United States)

Heidari Feidt, Raheleh; Ienca, Marcello; Elger, Bernice Simone; Folcher, Marc

2017-12-18

Advances at the interface between the biological sciences and engineering are giving rise to emerging research fields such as synthetic biology. Harnessing the potential of synthetic biology requires timely and adequate translation into clinical practice. However, the translational research enterprise is currently facing fundamental obstacles that slow down the transition of scientific discoveries from the laboratory to the patient bedside. These obstacles including scarce financial resources and deficiency of organizational and logistic settings are widely discussed as primary impediments to translational research. In addition, a number of socio-ethical considerations inherent in translational research need to be addressed. As the translational capacity of synthetic biology is tightly linked to its social acceptance and ethical approval, ethical limitations may-together with financial and organizational problems-be co-determinants of suboptimal translation. Therefore, an early assessment of such limitations will contribute to proactively favor successful translation and prevent the promising potential of synthetic biology from remaining under-expressed. Through the discussion of two case-specific inventions in synthetic biology and their associated ethical implications, we illustrate the socio-ethical challenges ahead in the process of implementing synthetic biology into clinical practice. Since reducing the translational lag is essential for delivering the benefits of basic biomedical research to society at large and promoting global health, we advocate a moral obligation to accelerating translational research: the "translational imperative."

Synthetic biology era: Improving antibiotic's world.

Science.gov (United States)

Guzmán-Trampe, Silvia; Ceapa, Corina D; Manzo-Ruiz, Monserrat; Sánchez, Sergio

2017-06-15

The emergence of antibiotic-resistant pathogen microorganisms is problematic in the context of the current spectrum of available medication. The poor specificity and the high toxicity of some available molecules have made imperative the search for new strategies to improve the specificity and to pursue the discovery of novel compounds with increased bioactivity. Using living cells as platforms, synthetic biology has counteracted this problem by offering novel pathways to create synthetic systems with improved and desired functions. Among many other biotechnological approaches, the advances in synthetic biology have made it possible to design and construct novel biological systems in order to look for new drugs with increased bioactivity. Advancements have also been made in the redesigning of RNA and DNA molecules in order to engineer antibiotic clusters for antibiotic overexpression. As for the production of these antibacterial compounds, yeasts and filamentous fungi as well as gene therapy are utilized to enhance protein solubility. Specific delivery is achieved by creating chimeras using plant genes into bacterial hosts. Some of these synthetic systems are currently in clinical trials, proving the proficiency of synthetic biology in terms of both pharmacological activities as well as an increase in the biosafety of treatments. It is possible that we may just be seeing the tip of the iceberg, and synthetic biology applications will overpass expectations beyond our present knowledge. Copyright © 2017. Published by Elsevier Inc.

Bertrand Competition with an Asymmetric No-Discrimination Constraint

NARCIS (Netherlands)

Bouckaert, J.M.C.; Degryse, H.A.; van Dijk, T.

2012-01-01

Abstract: We study the competitive and welfare consequences when only one firm must commit to uniform pricing while the competitor’s pricing policy is left unconstrained. The asymmetric no-discrimination constraint prohibits both behaviour-based price discrimination within the competitive segment

Enantioselective Access to Spirocyclic Sultams by Chiral Cp(x) -Rhodium(III)-Catalyzed Annulations.

Science.gov (United States)

Pham, Manh V; Cramer, Nicolai

2016-02-12

Chiral spirocyclic sultams are a valuable compound class in organic and medicinal chemistry. A rapid entry to this structural motif involves a [3+2] annulation of an N-sulfonyl ketimine and an alkyne. Although the directing-group properties of the imino group for C-H activation have been exploited, the developments of related asymmetric variants have remained very challenging. The use of rhodium(III) complexes equipped with a suitable atropchiral cyclopentadienyl ligand, in conjunction with a carboxylic acid additive, enables an enantioselective and high yielding access to such spirocyclic sultams. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.