WorldWideScience

Sample records for asymmetric guide strand

  1. Asymmetric Quantum Transport in a Double-Stranded Kronig-Penney Model

    Science.gov (United States)

    Cheon, Taksu; Poghosyan, Sergey S.

    2015-06-01

    We introduce a double-stranded Kronig-Penney model and analyze its transport properties. Asymmetric fluxes between two strands with suddenly alternating localization patterns are found as the energy is varied. The zero-size limit of the internal lines connecting two strands is examined using quantum graph vertices with four edges. We also consider a two-dimensional Kronig-Penney lattice with two types of alternating layer with δ and δ' connections, and show the existence of energy bands in which the quantum flux can flow only in selected directions.

  2. Oscillating Guided Modes in Graphene-Based Asymmetric Waveguides

    Institute of Scientific and Technical Information of China (English)

    PENG Ping; ZHANG Peng; LIU Jian-Ke; CAO Zhen-Zhou; LI Guan-Qiang

    2012-01-01

    We investigate the guided modes in monolayer graphene-based waveguides with asymmetric quantum well structure induced by unequal dc voltages. The dispersion relation for the guided modes is obtained analytically, the structures of the guided modes are discussed under three distinct cases. For the cases of the classical motion and the Klein tunneling, the asymmetric structure does not influence the mode structures dramatically compared with that in the symmetric waveguide. But for the mixing case of the former two, the mode structures and the motion characteristics for the electron and the hole exhibit different behaviors at same condition. The results may be helpful for the practical application of graphene-based quantum devices.

  3. Asymmetric bias in user guided segmentations of brain structures.

    Science.gov (United States)

    Maltbie, Eric; Bhatt, Kshamta; Paniagua, Beatriz; Smith, Rachel G; Graves, Michael M; Mosconi, Matthew W; Peterson, Sarah; White, Scott; Blocher, Joseph; El-Sayed, Mohammed; Hazlett, Heather C; Styner, Martin A

    2012-01-16

    Brain morphometric studies often incorporate comparative hemispheric asymmetry analyses of segmented brain structures. In this work, we present evidence that common user guided structural segmentation techniques exhibit strong left-right asymmetric biases and thus fundamentally influence any left-right asymmetry analyses. In this study, MRI scans from ten pediatric subjects were employed for studying segmentations of amygdala, globus pallidus, putamen, caudate, and lateral ventricle. Additionally, two pediatric and three adult scans were used for studying hippocampus segmentation. Segmentations of the sub-cortical structures were performed by skilled raters using standard manual and semi-automated methods. The left-right mirrored versions of each image were included in the data and segmented in a random order to assess potential left-right asymmetric bias. Using shape analysis we further assessed whether the asymmetric bias is consistent across subjects and raters with the focus on the hippocampus. The user guided segmentation techniques on the sub-cortical structures exhibited left-right asymmetric volume bias with the hippocampus displaying the most significant asymmetry values (pstudy is to raise awareness in the neuroimaging community regarding the presence of the asymmetric bias and its influence on any left-right hemispheric analyses. We also recommend reexamining previous research results in the light of this new finding.

  4. Persistence of seed-based activity following segmentation of a microRNA guide strand.

    Science.gov (United States)

    Chorn, Guillaume; Zhao, Lihong; Sachs, Alan B; Flanagan, W Michael; Lim, Lee P

    2010-12-01

    microRNAs are ∼ 22 nucleotide regulatory RNAs that are processed into duplexes from hairpin structures and incorporated into Argonaute proteins. Here, we show that a nick in the middle of the guide strand of an miRNA sequence allows for seed-based targeting characteristic of miRNA activity. Insertion of an inverted abasic, a dye, or a small gap between the two segments still permits target knockdown. While activity from the seed region of the segmented miRNA is apparent, activity from the 3' half of the guide strand is impaired, suggesting that an intact guide backbone is required for contribution from the 3' half. miRNA activity was also observed following nicking of a miRNA precursor. These results illustrate a structural flexibility in miRNA duplexes and may have applications in the design of miRNA mimetics.

  5. Guided modes in asymmetric metal-cladding left-handed material waveguides

    Institute of Scientific and Technical Information of China (English)

    Ying He; Xia Zhang; Yanfang Yang; Chunfang Li

    2011-01-01

    @@ We investigate guided modes in the asymmetric waveguide structure with a left-handed material (LHM) layer surrounded by air and metal.A graphical method is proposed to determine the guided modes.New properties of the oscillating and surface guided modes, such as absence of the fundamental mode,coexistence of the oscillating and surface guided modes, fast attenuation of the surface guided modes, and mode degeneracy, are analyzed in detail.%We investigate guided modes in the asymmetric waveguide structure with a left-handed material (LHM) layer surrounded by air and metal. A graphical method is proposed to determine the guided modes. New properties of the oscillating and surface guided modes, such as absence of the fundamental mode, coexistence of the oscillating and surface guided modes, fast attenuation of the surface guided modes, and mode degeneracy, are analyzed in detail. We also investigate dispersive characteristics of the metal-LHMair optical waveguide. The propagation constant increases with decreasing slab thickness for the first-order oscillating mode, which is different from that in traditional metal-cladding waveguides.

  6. On the Electron Agyrotropy during Rapid Asymmetric Magnetic Island Coalescence in Presence of a Guide Field

    CERN Document Server

    Cazzola, Emanuele; Goldman, Martin V; Newman, David L; Markidis, Stefano; Lapenta, Giovanni

    2016-01-01

    We present an analysis of the properties of the electron velocity distribution during island coalescence in asymmetric reconnection with and without guide field. In a previous study, three main domains were identified, in the case without guide field, as X-, D- and M-regions featuring different reconnection evolutions {Cazzola et al. 2015). These regions are also identified here in the case with guide field. We study the departure from isotropic and gyrotropic behavior by means of different robust detection algorithms proposed in the literature. While in the case without guide field these metrics show an overall agreement, when the guide field is present a discrepancy in the agyrotropy within some relevant regions is observed, such as at the separatrices and inside magnetic islands. Moreover, in light of the new observations from the Multiscale MagnetoSpheric mission, an analysis of the electron velocity phase-space in these domains is presented.

  7. An antemortem guide for the assessment of stranded Australian sea snakes (Hydrophiinae).

    Science.gov (United States)

    Gillett, Amber K; Flint, Mark; Mills, Paul C

    2014-12-01

    Marine snakes of the subfamily Hydrophiinae are obligate ocean dwellers, unlike their amphibious counterparts, the sea kraits (Laticaudinae), and as such they are often referred to as 'true' sea snakes. This specialization means that the presence of a true sea snake on a beach is atypical and likely indicates disease or injury. Traumatic injuries such as eye, jaw, and spinal lesions have been observed in stranded sea snakes and may present as acute injury or progress to chronic debilitation. Diseases, such as neoplasia, leukemia, and parasite overburden, have also been seen in wild sea snakes, and these animals may present similarly. Sick, moribund, or deceased sea snakes are intermittently found washed ashore along Australian beaches, and these specimens may prove valuable as bioindicators of marine health. This review is intended as a guide to the diagnostic investigation of sick or injured sea snakes by suitably qualified people.

  8. Asymmetric composite membranes from chitosan and tricalcium phosphate useful for guided bone regeneration.

    Science.gov (United States)

    Tai, Hung-Yin; Chou, Shiu-Huey; Cheng, Liao-Ping; Yu, Hung-Te; Don, Trong-Ming

    2012-01-01

    To fulfill the properties of barrier membranes useful for guided bone tissue regeneration in the treatment of periodontitis, in this study a simple process combining lyophilization with preheating treatment to produce asymmetric barrier membranes from biodegradable chitosan (CS) and functional β-tricalcium phosphate (TCP) was proposed. By preheating TCP/CS (3:10, w/w) in an acetic acid solution at 40°C, a skin layer that could greatly increase the mechanical properties of the membrane was formed. The asymmetric membrane with a skin layer had a modulus value almost 4-times that of the symmetric porous membrane produced only by lyophilization. This is beneficial for maintaining a secluded space for the bone regeneration, as well as to prevent the invasion of other tissues. The subsequent lyophilization at -20°C then gave the rest of material an interconnected pore structure with high porosity (83.9-90.6%) and suitable pore size (50-150 μm) which could promote the permeability and adhesiveness to bone cells, as demonstrated by the in vitro cell-culture of hFOB1.19 osteoblasts. Furthermore, the TCP particles added to CS could further increase the rigidity and the cell attachment and proliferation of hFOB1.19. The TCP/CS asymmetric composite membrane thus has the potential to be used as the barrier membrane for guided bone regeneration.

  9. A Data-Guided Lexisearch Algorithm for the Asymmetric Traveling Salesman Problem

    Directory of Open Access Journals (Sweden)

    Zakir Hussain Ahmed

    2011-01-01

    Full Text Available A simple lexisearch algorithm that uses path representation method for the asymmetric traveling salesman problem (ATSP is proposed, along with an illustrative example, to obtain exact optimal solution to the problem. Then a data-guided lexisearch algorithm is presented. First, the cost matrix of the problem is transposed depending on the variance of rows and columns, and then the simple lexisearch algorithm is applied. It is shown that this minor preprocessing of the data before the simple lexisearch algorithm is applied improves the computational time substantially. The efficiency of our algorithms to the problem against two existing algorithms has been examined for some TSPLIB and random instances of various sizes. The results show remarkably better performance of our algorithms, especially our data-guided algorithm.

  10. On the Electron Diffusion Region in Asymmetric Reconnection with a Guide Magnetic Field

    Science.gov (United States)

    Hesse, Michael; Liu, Yi-Hsin; Chen, Li-Jen; Bessho, Naoki; Kuznetsova, Masha; Birn, Joachim; Burch, James L.

    2016-01-01

    Particle-in-cell simulations in a 2.5-D geometry and analytical theory are employed to study the electron diffusion region in asymmetric reconnection with a guide magnetic field. The analysis presented here demonstrates that similar to the case without guide field, in-plane flow stagnation and null of the in-plane magnetic field are well separated. In addition, it is shown that the electric field at the local magnetic X point is again dominated by inertial effects, whereas it remains dominated by nongyrotropic pressure effects at the in-plane flow stagnation point. A comparison between local electron Larmor radii and the magnetic gradient scale lengths predicts that distribution should become nongyrotropic in a region enveloping both field reversal and flow stagnation points. This prediction is verified by an analysis of modeled electron distributions, which show clear evidence of mixing in the critical region.

  11. Peripheral nerve regeneration within an asymmetrically porous PLGA/Pluronic F127 nerve guide conduit.

    Science.gov (United States)

    Oh, Se Heang; Kim, Jun Ho; Song, Kyu Sang; Jeon, Byeong Hwa; Yoon, Jin Hwan; Seo, Tae Beom; Namgung, Uk; Lee, Il Woo; Lee, Jin Ho

    2008-04-01

    Asymmetrically porous tubes with selective permeability and hydrophilicity as nerve guide conduits (NGCs) were fabricated using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method. The inner surface of the tube had nano-size pores ( approximately 50nm) which can effectively prevent from fibrous tissue infiltration but permeate nutrients and retain neurotrophic factors, while the outer surface had micro-size pores ( approximately 50microm) which can allow vascular ingrowth for effective supply of nutrients into the tube. From the animal study using a rat model, the hydrophilized PLGA/F127 (3wt%) tube showed better nerve regeneration behavior than the control silicone or hydrophobic PLGA tubes, as investigated by immunohistochemical observation (by fluorescent microscopy with anti-neurofilament staining), histological observations (by light microscopy with toluidine blue staining and transmission electron microscopy), and electrophysiological evaluation (by compound muscle action potential measurement). This is probably owing to the effective permeation of nutrients and prevention of fibrous scar tissue invasion as well as the good mechanical strength of the tube to maintain a stable support structure for the nerve regeneration.

  12. A field guide to eukaryotic circular single-stranded DNA viruses: insights gained from metagenomics.

    Science.gov (United States)

    Rosario, Karyna; Duffy, Siobain; Breitbart, Mya

    2012-10-01

    Despite their small size and limited protein-coding capacity, the rapid evolution rates of single-stranded DNA (ssDNA) viruses have led to their emergence as serious plant and animal pathogens. Recently, metagenomics has revealed an unprecedented diversity of ssDNA viruses, expanding their known environmental distributions and host ranges. This review summarizes and contrasts the basic characteristics of known circular ssDNA viral groups, providing a resource for analyzing the wealth of ssDNA viral sequences identified through metagenomics. Since ssDNA viruses are largely identified based on conserved rolling circle replication proteins, this review highlights distinguishing motifs and catalytic residues important for replication. Genomes identified through metagenomics have demonstrated unique ssDNA viral genome architectures and revealed characteristics that blur the boundaries between previously well-defined groups. Metagenomic discovery of ssDNA viruses has created both a challenge to current taxonomic classification schemes and an opportunity to revisit hypotheses regarding the evolutionary history of these viruses.

  13. MMS observations of plasma wave and electron energization in the electron diffusion region of asymmetric reconnection with strong guide field

    Science.gov (United States)

    Xiao, Chijie; Zhao, Siqi; Shi, Mijie; Pu, Zuyin; Wang, Xiaogang

    2016-10-01

    Here we report an asymmetric reconnection event with strong guide field observed by Magnetospheric Multiscale Mission (MMS) on the dayside magnetopause. In this event there are multiple wave modes, such as electron Alfvenic mode, broadband waves between the lower-hybrid and electron cyclotron frequencies, exist in the vicinity of the electron diffusion region and the separatrix. And the electron velocity distribution functions show that bi-stream electrons with low energy (processes are investigated and comparison with some 3D numerical simulation results. This work was supported by NSFC (Grants 41274168 and 11375053).

  14. Dispersion curve veering of longitudinal guided waves propagating inside prestressed seven-wire strands

    Science.gov (United States)

    Treyssède, Fabien

    2016-04-01

    Elastic guided waves are of interest for the non-destructive evaluation of cables. Such structures are usually helical, multiwired and highly prestressed, which greatly complicates the understanding of wave propagation from a theoretical point of view. A remarkable feature is the occurrence of a missing frequency band in experimental time-frequency diagrams, sometimes referred to as notch frequency in the literature. The central frequency of this band increases under tensile loads. Recently, a numerical model has been proposed to compute the dispersion curves of prestressed helical seven-wire waveguides. Results have shown that the notch frequency indeed corresponds to a curve veering phenomenon between two longitudinal-like modes and that the increase of the notch under tensile loads is mainly due to interwire contact mechanisms. The main goal of this paper is to highlight the origin of this curve veering phenomenon, which is still unexplained up to the author's knowledge. This paper also provides further results which allow us to clarify the accuracy of numerical solutions as well as the influence of contact assumptions. First, the static part of the model, necessary to compute the prestress state including contact effects, is checked from reference analytical solutions. Owing to the importance of contact, the accuracy of results is discussed both in statics and in dynamics. The influence of slip contact conditions is outlined. Then, some numerical tests are conducted by varying the Poisson coefficient and the helix lay angle. These tests allows us to find out that the radial displacement constraint imposed on peripheral wires by the central one in the contact regions constitutes the main source of curve veering. More precisely, it is shown that a similar curve veering does occur for an uncoupled single peripheral wire when constrained by a radially blocked motion localized in its contact zone. Indeed, such a localized boundary condition completely breaks the

  15. Acceleration of Peripheral Nerve Regeneration through Asymmetrically Porous Nerve Guide Conduit Applied with Biological/Physical Stimulation

    Science.gov (United States)

    Kim, Jin Rae; Oh, Se Heang; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Jeon, Byeong Hwa

    2013-01-01

    Sufficient functional restoration of damaged peripheral nerves is a big clinical challenge. In this study, a nerve guide conduit (NGC) with selective permeability was prepared by rolling an asymmetrically porous polycaprolactone/Pluronic F127 membrane fabricated using a novel immersion precipitation method. Dual stimulation (nerve growth factor [NGF] as a biological stimulus and low-intensity pulse ultrasound [US] as a physical stimulus) was adapted to enhance nerve regeneration through an NGC. The animal study revealed that each stimulation (NGF or US) has a positive effect to promote the peripheral nerve regeneration through the NGC, however, the US-stimulated NGC group allowed more accelerated nerve regeneration compared with the NGF-stimulated group. The NGC group that received dual stimulation (NGF and US) showed more effective nerve regeneration behavior than the groups that received a single stimulation (NGF or US). The asymmetrically porous NGC with dual NGF and US stimulation may be a promising strategy for the clinical treatment of delayed and insufficient functional recovery of a peripheral nerve. PMID:23859225

  16. Acceleration of peripheral nerve regeneration through asymmetrically porous nerve guide conduit applied with biological/physical stimulation.

    Science.gov (United States)

    Kim, Jin Rae; Oh, Se Heang; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Jeon, Byeong Hwa; Lee, Jin Ho

    2013-12-01

    Sufficient functional restoration of damaged peripheral nerves is a big clinical challenge. In this study, a nerve guide conduit (NGC) with selective permeability was prepared by rolling an asymmetrically porous polycaprolactone/Pluronic F127 membrane fabricated using a novel immersion precipitation method. Dual stimulation (nerve growth factor [NGF] as a biological stimulus and low-intensity pulse ultrasound [US] as a physical stimulus) was adapted to enhance nerve regeneration through an NGC. The animal study revealed that each stimulation (NGF or US) has a positive effect to promote the peripheral nerve regeneration through the NGC, however, the US-stimulated NGC group allowed more accelerated nerve regeneration compared with the NGF-stimulated group. The NGC group that received dual stimulation (NGF and US) showed more effective nerve regeneration behavior than the groups that received a single stimulation (NGF or US). The asymmetrically porous NGC with dual NGF and US stimulation may be a promising strategy for the clinical treatment of delayed and insufficient functional recovery of a peripheral nerve.

  17. Ultrasound-stimulated peripheral nerve regeneration within asymmetrically porous PLGA/Pluronic F127 nerve guide conduit.

    Science.gov (United States)

    Park, Sang Chul; Oh, Se Heang; Seo, Tae Beom; Namgung, Uk; Kim, Jin Man; Lee, Jin Ho

    2010-08-01

    Recently, we developed a novel method to fabricate a nerve guide conduit (NGC) with asymmetrical pore structure and hydrophilicity using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method. From the animal study using a rat model (sciatic nerve defect of rat), we recognized that the unique PLGA/Pluronic F127 tube provided good environments for nerve regeneration. In this study, we applied low-intensity pulsed ultrasound as a simple and noninvasive stimulus at the PLGA/F127 NGC-implanted site transcutaneously in rats to investigate the feasibility of ultrasound for the enhanced nerve regeneration through the tube. The nerve regeneration behaviors within the ultrasound-stimulated PLGA/Pluronic F127 NGCs were compared with the NGCs without the ultrasound treatment as well as normal nerve by histological and immunohistochemical observations. It was observed that the PLGA/Pluronic F127 tube-implanted group applied with the ultrasound had more rapid nerve regeneration behavior (approximately 0.71 mm/day) than the tube-implanted group without the ultrasound treatment (approximately 0.48 mm/day). The ultrasound-treated tube group also showed greater neural tissue area as well as larger axon diameter and thicker myelin sheath than the tube group without the ultrasound treatment, indicating better nerve regeneration. The better nerve regeneration behavior in the our NGC/ultrasound system may be caused by the synergistic effect of the asymmetrically porous PLGA/Pluronic F127 tube with unique properties (selective permeability, hydrophilicity, and structural stability, which can provide good environment for nerve regeneration) and physical stimulus (stimulation of the Schwann cells and activation of the neurotrophic factors).

  18. Mechanism-guided development of VO(salen)X complexes as catalysts for the asymmetric synthesis of cyanohydrin trimethylsilyl ethers.

    Science.gov (United States)

    Belokon, Yuri N; Clegg, William; Harrington, Ross W; Maleev, Victor I; North, Michael; Pujol, Marta Omedes; Usanov, Dmitry L; Young, Carl

    2009-01-01

    Catalyze this! Detailed study of the mechanism of asymmetric cyanohydrin synthesis catalyzed by VO(salen)X complexes (see figure) led to the development of VO(salen)NCS, as the most active vanadium-based catalyst yet developed for this reaction.The mechanism by which oxovanadium(V)(salen) complexes(1) VO(salen)X catalyze the asymmetric addition of trimethylsilyl cyanide to benzaldehyde has been studied. The reaction kinetics indicated that the structure of the counterion (X) had a significant influence on the rate, but not on the enantioselectivity of the reaction. The less coordinating the counterion, the lower the catalytic activity; a trend that was confirmed by a Hammett analysis. Variable temperature kinetics allowed the enthalpies and entropies of activation to be determined for some catalysts, and showed that, for others, the overall reaction order changes from second order to zero order as the temperature is reduced. The order with respect to the catalyst was determined for nine of the VO(salen)X complexes and showed that the less active catalysts were active predominantly as mononuclear species whilst the more active catalysts were active predominantly as dinuclear species. Mass spectrometry confirmed the formation of dinuclear species in situ from all of the VO(salen)X complexes and indicated that the dinuclear complexes contained one vanadium(V) and one vanadium(IV) ion. The latter conclusion was supported by cyclic voltammetry of the complexes, by fluorescence measurements and by the fact that catalyst deactivation occurs when reactions are carried out under an inert atmosphere. Based on this evidence, it has been deduced that the catalysis involves two catalytic cycles: one for catalysis by mononuclear VO(salen)X species and the other for catalysis by dinuclear species. The catalytic cycle involving dinuclear species involves activation of both the cyanide and aldehyde, whereas the catalytic cycle involving mononuclear species activates only the

  19. On the Electron Dynamics during Rapid Asymmetric Magnetic Island Coalescence: Insights on the Electrons Agyrotropy with the Presence of a Guide Field

    Science.gov (United States)

    Cazzola, Emanuele; Lapenta, Giovanni; Innocenti, Maria Elena; Goldman, Martin; Newman, David; Markidis, Stefano

    2016-04-01

    The work presents a fully kinetic analysis of the electrons dynamics during rapid island coalescence in asymmetric magnetic reconnection, especially focused on the comparison between the case with and with no initial guide field. Formation and growth of the islands are caused by an intentionally unstable initial configuration across the current sheet with the same asymmetric profiles as those traditionally proposed in the literature (e.g. Pritchett, 2008). Particular attentions is given to the different evolution of the presumed reconnection sites. Three main regions are eventually identified, named by X-, D- and M-regions, which describe, respectively, the regions featuring a traditional reconnection event, those showing an opposite behavior with respect to the former and the reconnection regions occurring between two magnetic islands (Cazzola et al., 2015). Further analysis is mainly addressed to evaluate both the electrons departure from the isotropic and gyrotropic behavior. Whether the first quantity has been clearly established and confirmed by observations, the latter has always appeared of difficult interpretation, and an ultimate accepted method on how to render it from PIC simulations still seems far to be achieved. In light of the upcoming data from the freshly launched MMS NASA mission, outcomes from some of the main techniques to spot agyrotropic regions are here compared to highligh the presence of possible relevant differences (Scudder and Daughton, 2008; Swisdak, 2015). References [1] P. Pritchett, "Collisionless magnetic reconnection in an asymmetric current sheet," Journal of Geophysical Research: Space Physics (1978-2012), vol. 113, no. A6, 2008. [2] E. Cazzola, M. E. Innocenti, S. Markidis, M. V. Goldman, D. L. Newman, and G. Lapenta, "On the electron dynamics during island coalescence in asymmetric magnetic reconnection," Physics of Plasmas (1994-present), vol. 22, no. 9, p. 092901, 2015. [3] J. Scudder and W. Daughton, "Illuminating electron

  20. Dispersion relationship for guided modes in bilayer graphene-based asymmetric waveguides%双层石墨烯非对称波导中导模的色散关系

    Institute of Scientific and Technical Information of China (English)

    彭娉; 李冠强; 张鹏; 刘建科

    2012-01-01

    Based on the Hamiltonian of carriers in bilayer graphene with energy band gap, the existence of the guided modes in asymmetric waveguides induced by the unequal external potentials is investigated. Given the wavefunctions for the different regions and using the continuity conditions at the interfaces of the potential barriers, the dispersion relationship for the guided modes in asymmetric waveguides is derived analytically. Meanwhile, the effect of the energy band gap on the characteristic of the guided modes is discussed. This study will provide a theoretical basis for the practical applications of bilayer graphene-based waveguide devices.%从具有能隙的双层石墨烯载流子所满足的哈密顿量出发,研究了非对称外势产生的波导结构中导模的存在性.在给定不同外势区域波函数的情况下,利用势垒边界处波函数的连续性条件,解析推导出了非对称波导中导模的色散关系,讨论了双层石墨烯的能隙对导模性质的影响.该研究为基于双层石墨烯波导器件的实际应用提供了理论依据.

  1. Stranded Specimen Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Mammal and Turtle Division collects data about individual cetaceans and sea turtles that come ashore, or strand on the beach. The date and location of...

  2. Alaska Beluga Strandings

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NMFS is mandated by the Marine Mammal Protection Act (MMPA) to collect reports of marine mammal stranding events. This particular catalogue item is specific to the...

  3. Whale strandings: hypothesis.

    Science.gov (United States)

    Mawson, A R

    1978-01-01

    The hypothesis is presented that whales become stranded inadvertently as a consequence of seeking stimulation. The animals enter shallow water in order to roll over, bask, and rub themselves in the sand, and are trapped by the receding tide. It suggested that stimulation-seeking behavior (and stranding) reflects a general sympathetic nervous system response which may be due to a number of factors such as pain, discomfort, reproductive state, and other biorhythmic changes.

  4. Crystal structure of four-stranded Oxytricha telomeric DNA

    Science.gov (United States)

    Kang, C.; Zhang, X.; Ratliff, R.; Moyzis, R.; Rich, A.

    1992-01-01

    The sequence d(GGGGTTTTGGGG) from the 3' overhang of the Oxytricha telomere has been crystallized and its three-dimensional structure solved to 2.5 A resolution. The oligonucleotide forms hairpins, two of which join to make a four-stranded helical structure with the loops containing four thymine residues at either end. The guanine residues are held together by cyclic hydrogen bonding and an ion is located in the centre. The four guanine residues in each segment have a glycosyl conformation that alternates between anti and syn. There are two four-stranded molecules in the asymmetric unit showing that the structure has some intrinsic flexibility.

  5. Asymmetric Ashes

    Science.gov (United States)

    2006-11-01

    that oscillate in certain directions. Reflection or scattering of light favours certain orientations of the electric and magnetic fields over others. This is why polarising sunglasses can filter out the glint of sunlight reflected off a pond. When light scatters through the expanding debris of a supernova, it retains information about the orientation of the scattering layers. If the supernova is spherically symmetric, all orientations will be present equally and will average out, so there will be no net polarisation. If, however, the gas shell is not round, a slight net polarisation will be imprinted on the light. This is what broad-band polarimetry can accomplish. If additional spectral information is available ('spectro-polarimetry'), one can determine whether the asymmetry is in the continuum light or in some spectral lines. In the case of the Type Ia supernovae, the astronomers found that the continuum polarisation is very small so that the overall shape of the explosion is crudely spherical. But the much larger polarization in strongly blue-shifted spectral lines evidences the presence, in the outer regions, of fast moving clumps with peculiar chemical composition. "Our study reveals that explosions of Type Ia supernovae are really three-dimensional phenomena," says Dietrich Baade. "The outer regions of the blast cloud is asymmetric, with different materials found in 'clumps', while the inner regions are smooth." "This study was possible because polarimetry could unfold its full strength thanks to the light-collecting power of the Very Large Telescope and the very precise calibration of the FORS instrument," he adds. The research team first spotted this asymmetry in 2003, as part of the same observational campaign (ESO PR 23/03 and ESO PR Photo 26/05). The new, more extensive results show that the degree of polarisation and, hence, the asphericity, correlates with the intrinsic brightness of the explosion. The brighter the supernova, the smoother, or less clumpy

  6. Strand SPA & Konverentsikeskus

    Index Scriptorium Estoniae

    2008-01-01

    Strand SPA & Konverentsikeskus on Pärnu suurim äri- ja konverentsiklientidele suunatud hotell, mis klientide seas on hinnatud just selle kompleksuse tõttu, kuna kõik, mida külaline vajab ja soovib, on olemas ühe katuse all

  7. Op het strand

    NARCIS (Netherlands)

    Boer, M.G. de

    2010-01-01

    SAMENVATTING Het woord spiaggia ‘strand’ wordt besproken binnen het veld van woorden die een scheiding tussen land en water aangeven. Hierbij worden historisch verschillende scenario’s (frames) onderscheiden, al naar de functie de het strand destijds had. Spiaggia wordt vergeleken met zijn synoniem

  8. LHC superconducting strand

    CERN Multimedia

    Patrice Loiez

    1999-01-01

    This cross-section through a strand of superconducting matieral as used in the LHC shows the 8000 Niobium-Titanium filaments embedded like a honeycomb in copper. When cooled to 1.9 degrees above absolute zero in the LHC accelerator, these filaments will have zero resistance and so will carry a high electric current with no energy loss.

  9. Childhood asymmetrical labium majus enlargement sonographic and MR imaging appearances

    Energy Technology Data Exchange (ETDEWEB)

    Gokli, Ami; Neuman, Jeremy; Lukse, Ruby; Koshy, June [Staten Island University Hospital, Department of Radiology, Staten Island, NY (United States); Kong, Fanyi [Staten Island University Hospital, Department of Pathology, Staten Island, NY (United States); Laor, Tal [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2016-05-15

    Childhood asymmetrical labium majus enlargement (CALME) has been described sparsely in recent surgery, pathology, pediatric and gynecology literature; however, no comprehensive description from a radiology perspective has been developed. The purpose of this case series is to describe the imaging findings of CALME and to review the current understanding of this recently described clinical entity with regard to clinical presentation, pathophysiology, differential diagnosis and treatment options. This is a retrospective analysis of 3 girls, ages 5-7 years, who presented for imaging evaluation with subsequent pathologically proven CALME. Each child's clinical history, length of symptoms, imaging appearance and pathological findings were reviewed. All three girls presented with unilateral enlargement of the labium majus (two right-side, one left-side) with no history of trauma or other inciting cause. Two girls had painless labial enlargement that was recognized for weeks, and one had similar symptoms for 1 year prior to presentation. One girl was evaluated initially with sonography, and all three children underwent MR imaging. Sonographic evaluation showed asymmetrical labial enlargement without a definable mass. In each girl, the MR imaging findings were characterized by relatively ill-defined T1-weighted hypointense signal, T2-weighted hypo- to isointense signal with interspersed hyperintense septae, and heterogeneous patchy and feathery strands of enhancement on post-contrast imaging. Biopsy from each child showed benign fibrous tissue with intervening mature fibroadipose tissue, vessels and nerves without findings of inflammation or neoplasia. The MR imaging appearance of CALME is consistent. Recognition and appreciation of this unique pediatric entity by the radiologist may be essential for appropriate diagnosis and can help to guide therapy. Current preferred treatment approach is conservative. (orig.)

  10. Mismatch repair balances leading and lagging strand DNA replication fidelity.

    Directory of Open Access Journals (Sweden)

    Scott A Lujan

    Full Text Available The two DNA strands of the nuclear genome are replicated asymmetrically using three DNA polymerases, α, δ, and ε. Current evidence suggests that DNA polymerase ε (Pol ε is the primary leading strand replicase, whereas Pols α and δ primarily perform lagging strand replication. The fact that these polymerases differ in fidelity and error specificity is interesting in light of the fact that the stability of the nuclear genome depends in part on the ability of mismatch repair (MMR to correct different mismatches generated in different contexts during replication. Here we provide the first comparison, to our knowledge, of the efficiency of MMR of leading and lagging strand replication errors. We first use the strand-biased ribonucleotide incorporation propensity of a Pol ε mutator variant to confirm that Pol ε is the primary leading strand replicase in Saccharomyces cerevisiae. We then use polymerase-specific error signatures to show that MMR efficiency in vivo strongly depends on the polymerase, the mismatch composition, and the location of the mismatch. An extreme case of variation by location is a T-T mismatch that is refractory to MMR. This mismatch is flanked by an AT-rich triplet repeat sequence that, when interrupted, restores MMR to > 95% efficiency. Thus this natural DNA sequence suppresses MMR, placing a nearby base pair at high risk of mutation due to leading strand replication infidelity. We find that, overall, MMR most efficiently corrects the most potentially deleterious errors (indels and then the most common substitution mismatches. In combination with earlier studies, the results suggest that significant differences exist in the generation and repair of Pol α, δ, and ε replication errors, but in a generally complementary manner that results in high-fidelity replication of both DNA strands of the yeast nuclear genome.

  11. The causes of whale strandings.

    Science.gov (United States)

    Cordes, D O

    1982-03-01

    Strandings of cetaceans (whales and dolphins) is probably the result of a sequence of events rather than a simple cause-and-effect relationship. Strandings of solitary animals are more common than massed and generally thought to be due to severe disease. Mass strandings (three to several hundred individuals) are less common, but very spectacular. Mass strandings are considered to be due to a complex of factors in which behavioural factors are probably important, severe disease making an unimportant, or negligible contribution. There may be interaction of physical conditions (weather, tides, currents, coastline) and biological conditions (predators, feeding, disturbance of echolocation and disease) which result in stranding. One postulated reason for stranding is that it is dependent on instinctive behaviour, deeply located in subcortical areas of the brain, which provokes cetaceans to seek refuge ashore when under stress.

  12. OligArch: A software tool to allow artificially expanded genetic information systems (AEGIS to guide the autonomous self-assembly of long DNA constructs from multiple DNA single strands

    Directory of Open Access Journals (Sweden)

    Kevin M. Bradley

    2014-08-01

    Full Text Available Synthetic biologists wishing to self-assemble large DNA (L-DNA constructs from small DNA fragments made by automated synthesis need fragments that hybridize predictably. Such predictability is difficult to obtain with nucleotides built from just the four standard nucleotides. Natural DNA's peculiar combination of strong and weak G:C and A:T pairs, the context-dependence of the strengths of those pairs, unimolecular strand folding that competes with desired interstrand hybridization, and non-Watson–Crick interactions available to standard DNA, all contribute to this unpredictability. In principle, adding extra nucleotides to the genetic alphabet can improve the predictability and reliability of autonomous DNA self-assembly, simply by increasing the information density of oligonucleotide sequences. These extra nucleotides are now available as parts of artificially expanded genetic information systems (AEGIS, and tools are now available to generate entirely standard DNA from AEGIS DNA during PCR amplification. Here, we describe the OligArch (for "oligonucleotide architecting" software, an application that permits synthetic biologists to engineer optimally self-assembling DNA constructs from both six- and eight-letter AEGIS alphabets. This software has been used to design oligonucleotides that self-assemble to form complete genes from 20 or more single-stranded synthetic oligonucleotides. OligArch is therefore a key element of a scalable and integrated infrastructure for the rapid and designed engineering of biology.

  13. Transcription-induced mutational strand bias and its effect on substitution rates in human genes.

    Science.gov (United States)

    Mugal, Carina F; von Grünberg, Hans-Hennig; Peifer, Martin

    2009-01-01

    If substitution rates are not the same on the two complementary DNA strands, a substitution is considered strand asymmetric. Such substitutional strand asymmetries are determined here for the three most frequent types of substitution on the human genome (C --> T, A --> G, and G --> T). Substitution rate differences between both strands are estimated for 4,590 human genes by aligning all repeats occurring within the introns with their ancestral consensus sequences. For 1,630 of these genes, both coding strand and noncoding strand rates could be compared with rates in gene-flanking regions. All three rates considered are found to be on average higher on the coding strand and lower on the transcribed strand in comparison to their values in the gene-flanking regions. This finding points to the simultaneous action of rate-increasing effects on the coding strand--such as increased adenine and cytosine deamination--and transcription-coupled repair as a rate-reducing effect on the transcribed strand. The common behavior of the three rates leads to strong correlations of the rate asymmetries: Whenever one rate is strand biased, the other two rates are likely to show the same bias. Furthermore, we determine all three rate asymmetries as a function of time: the A --> G and G --> T rate asymmetries are both found to be constant in time, whereas the C --> T rate asymmetry shows a pronounced time dependence, an observation that explains the difference between our results and those of an earlier work by Green et al. (2003. Transcription-associated mutational asymmetry in mammalian evolution. Nat Genet. 33:514-517.). Finally, we show that in addition to transcription also the replication process biases the substitution rates in genes.

  14. 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.

  15. Fair Exchange in Strand Spaces

    Directory of Open Access Journals (Sweden)

    Joshua D. Guttman

    2009-10-01

    Full Text Available Many cryptographic protocols are intended to coordinate state changes among principals. Exchange protocols coordinate delivery of new values to the participants, e.g. additions to the set of values they possess. An exchange protocol is fair if it ensures that delivery of new values is balanced: If one participant obtains a new possession via the protocol, then all other participants will, too. Fair exchange requires progress assumptions, unlike some other protocol properties. The strand space model is a framework for design and verification of cryptographic protocols. A strand is a local behavior of a single principal in a single session of a protocol. A bundle is a partially ordered global execution built from protocol strands and adversary activities. The strand space model needs two additions for fair exchange protocols. First, we regard the state as a multiset of facts, and we allow strands to cause changes in this state via multiset rewriting. Second, progress assumptions stipulate that some channels are resilient-and guaranteed to deliver messages-and some principals are assumed not to stop at certain critical steps. This method leads to proofs of correctness that cleanly separate protocol properties, such as authentication and confidentiality, from invariants governing state evolution. G. Wang's recent fair exchange protocol illustrates the approach.

  16. Asymmetrical international attitudes

    NARCIS (Netherlands)

    Van Oudenhoven, JP; Askevis-Leherpeux, F; Hannover, B; Jaarsma, R; Dardenne, B

    2002-01-01

    In general, attitudes towards nations have a fair amount of reciprocity: nations either like each other are relatively indifferent to each other or dislike each other Sometimes, however international attitudes are asymmetrical. In this study, we use social identity theory in order to explain asymmet

  17. Asymmetric reactions in continuous flow

    Directory of Open Access Journals (Sweden)

    Xiao Yin Mak

    2009-04-01

    Full Text Available An overview of asymmetric synthesis in continuous flow and microreactors is presented in this review. Applications of homogeneous and heterogeneous asymmetric catalysis as well as biocatalysis in flow are discussed.

  18. Asymmetric catalysis with helical polymers

    NARCIS (Netherlands)

    Megens, Rik P.; Roelfes, Gerard

    2011-01-01

    Inspired by nature, the use of helical biopolymer catalysts has emerged over the last years as a new approach to asymmetric catalysis. In this Concept article the various approaches and designs and their application in asymmetric catalysis will be discussed.

  19. Cryptography with DNA binary strands.

    Science.gov (United States)

    Leier, A; Richter, C; Banzhaf, W; Rauhe, H

    2000-06-01

    Biotechnological methods can be used for cryptography. Here two different cryptographic approaches based on DNA binary strands are shown. The first approach shows how DNA binary strands can be used for steganography, a technique of encryption by information hiding, to provide rapid encryption and decryption. It is shown that DNA steganography based on DNA binary strands is secure under the assumption that an interceptor has the same technological capabilities as sender and receiver of encrypted messages. The second approach shown here is based on steganography and a method of graphical subtraction of binary gel-images. It can be used to constitute a molecular checksum and can be combined with the first approach to support encryption. DNA cryptography might become of practical relevance in the context of labelling organic and inorganic materials with DNA 'barcodes'.

  20. 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.

  1. Asymmetric extractions in orthodontics

    OpenAIRE

    Camilo Aquino Melgaço; Mônica Tirre de Souza Araújo

    2012-01-01

    INTRODUCTION: Extraction decisions are extremely important in during treatment planning. In addition to the extraction decision orthodontists have to choose what tooth should be extracted for the best solution of the problem and the esthetic/functional benefit of the patient. OBJECTIVE: This article aims at reviewing the literature relating the advantages, disadvantages and clinical implications of asymmetric extractions to orthodontics. METHODS: Keywords were selected in English and Portugue...

  2. Asymmetric Evolutionary Games.

    Directory of Open Access Journals (Sweden)

    Alex McAvoy

    2015-08-01

    Full Text Available 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.

  3. Asymmetric extractions in orthodontics

    Directory of Open Access Journals (Sweden)

    Camilo Aquino Melgaço

    2012-04-01

    Full Text Available INTRODUCTION: Extraction decisions are extremely important in during treatment planning. In addition to the extraction decision orthodontists have to choose what tooth should be extracted for the best solution of the problem and the esthetic/functional benefit of the patient. OBJECTIVE: This article aims at reviewing the literature relating the advantages, disadvantages and clinical implications of asymmetric extractions to orthodontics. METHODS: Keywords were selected in English and Portuguese and the EndNote 9 program was used for data base search in PubMed, Web of Science (WSc and LILACS. The selected articles were case reports, original articles and prospective or retrospective case-control studies concerning asymmetrical extractions of permanent teeth for the treatment of malocclusions. CONCLUSION: According to the literature reviewed asymmetric extractions can make some specific treatment mechanics easier. Cases finished with first permanent molars in Class II or III relationship in one or both sides seem not to cause esthetic or functional problems. However, diagnosis knowledge and mechanics control are essential for treatment success.

  4. 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.

  5. Southeast US Historical Marine Mammal Stranding Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data on marine mammal strandings are collected by the Southeast Marine Mammal Stranding Network. Basic data on the location, species identification, animal...

  6. The Stranding Anomaly as Population Indicator

    DEFF Research Database (Denmark)

    Peltier, Helene; Baagøe, Hans J.; Camphuysen, Kees C.J.

    2013-01-01

    Ecological indicators for monitoring strategies are expected to combine three major characteristics: ecological significance, statistical credibility, and cost-effectiveness. Strategies based on stranding networks rank highly in cost-effectiveness, but their ecological significance and statistical...... credibility are disputed. Our present goal is to improve the value of stranding data as population indicator as part of monitoring strategies by constructing the spatial and temporal null hypothesis for strandings. The null hypothesis is defined as: small cetacean distribution and mortality are uniform...... porpoise Phocoena phocoena for our modelling. The difference between these strandings expected under H0 and observed strandings is defined as the stranding anomaly. It constituted the stranding data series corrected for drift conditions. Seasonal decomposition of stranding anomaly suggested that drift...

  7. Hyperchromicity and strand separation in bacterial DNA.

    Science.gov (United States)

    FREIFELDER, D; DAVISON, P F

    1962-05-01

    Studies of the per cent of strand separation of N(14)-N(15) hybrid coli DNA heated to various temperatures in formaldehyde have shown that the process of strand separation is a function of temperature and formaldehyde concentration and is directly related to the measured hyperchromicity. No strands separate until about 75 per cent of full hyperchromicity is obtained, and even at apparently full hyperchromicity a large fraction of the strands may be held together, possibly by guanine-cytosine-rich regions.

  8. ELASTIC DEFORMATION ANALYSIS OF MULTILA YERED STRANDS

    Institute of Scientific and Technical Information of China (English)

    王世文; 冯继玲; 杨兆建; 连香姣

    1999-01-01

    This paper describes a general model for the mechanical behavior studying of general wire rope strand. An exact solution of the deformation characteristics was given when the strands is under tensile and torsional loads. The theoretical results are useful in evaluating the extensional and torsional moduli of rigidity for the strands. Finally, a simple design criterion is established for the nonrotating ropes.

  9. 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.

  10. Asymmetric synthesis v.4

    CERN Document Server

    Morrison, James

    1984-01-01

    Asymmetric Synthesis, Volume 4: The Chiral Carbon Pool and Chiral Sulfur, Nitrogen, Phosphorus, and Silicon Centers describes the practical methods of obtaining chiral fragments. Divided into five chapters, this book specifically examines initial chiral transmission and extension. The opening chapter describes the so-called chiral carbon pool, the readily available chiral carbon fragments used as building blocks in synthesis. This chapter also provides a list of 375 chiral building blocks, along with their commercial sources, approximate prices, and methods of synthesis. Schemes involving

  11. Asymmetric flow networks

    OpenAIRE

    Olaizola Ortega, María Norma; Valenciano Llovera, Federico

    2012-01-01

    This paper provides a new model of network formation that bridges the gap between the two benchmark models by Bala and Goyal, the one-way flow model, and the two-way flow model, and includes both as particular extreme cases. As in both benchmark models, in what we call an "asymmetric flow" network a link can be initiated unilaterally by any player with any other, and the flow through a link towards the player who supports it is perfect. Unlike those models, in the opposite direction there is ...

  12. LASIK for correcting irregular astigmatism and asymmetrical astigmatism guided by corneal topography%角膜地形图引导下准分子激光矫正角膜不规则散光及不对称性散光

    Institute of Scientific and Technical Information of China (English)

    吴震; 荆翠红; 韩九娥; 蔡娟娟; 李水仙; 王运红; 吴化宇

    2012-01-01

    目的 探讨角膜地形图引导下准分子激光个性化切削手术矫正角膜不规则散光及不对称性散光的效果和优缺点.方法 应用MEL - 70准分子激光仪及配套TOMEY -Ⅲ角膜地形图引导个性化切削系统进行准分子激光原位角膜磨镶术(LASIK)矫正不对称性或不规则角膜散光复性近视散光58例108眼.其中49例97眼为初次手术;另9例11眼为二次手术,系由不均匀切削、偏心切削或中央岛而形成的不规则散光.术前最佳矫正视力均值0.98±0.32;屈光度:球镜平均(-4.59±1.68)D,柱镜平均(-1.62±0.78)D.结果 108眼手术均顺利完成,无术中或术后并发症.术后角膜地形图显示:角膜中央3 mm切削深度平整、均匀,术后1周平均裸眼视力1.03 ±0.29.屈光度:球镜-0.50~+0.75D,平均(-0.35 ±0.29)D,柱镜0~- 0.75D,平均(-0.38 ±0.24)D.结论 TOMEY -Ⅲ角膜地形图捕捉角膜曲率信息准确,引导准分子激光个性化切削程序设计合理,系统安全可靠.用它来进行个性化LASIK可较为精确地矫正角膜不规则及不对称散光.%Objective To discuss the effect of laser in situ keratomileusis (LASIK) for correcting irregular astigmatism and asymmetrical astigmatism guided by corneal topographic map.Methods There were 58 cases( 108 eyes) with compound myopic astigmatism,asymmetric or irregular corneal astigmatism accepted LASIK under MEL- 70 excimer laser that guided by TOMEY-Ⅲ corneal topography.49 patients (97 eyes) received their first operation on the eye.9 patients ( 11 eyes) with irregular astigmatism due to uneven cutting,eccentric cutting or central island received the second operation on the same eye.The preoperative best corrected visual acuity was on average of 0.98 ± 0.32,Sphere ( - 4.59 ± 1.68 ) D,Cylinder ( - 1.62 ± 0.78) D.Results 108 operations were successfully finished without intraoperative or postoperative complications.Corneal topography showed the centra 3 mm cutting was depth uniform

  13. Two-Domain DNA Strand Displacement

    CERN Document Server

    Cardelli, Luca

    2010-01-01

    We investigate the computing power of a restricted class of DNA strand displacement structures: those that are made of double strands with nicks (interruptions) in the top strand. To preserve this structural invariant, we impose restrictions on the single strands they interact with: we consider only two-domain single strands consisting of one toehold domain and one recognition domain. We study fork and join signal-processing gates based on these structures, and we show that these systems are amenable to formalization and to mechanical verification.

  14. Autonomous Generation and Loading of DNA Guides by Bacterial Argonaute.

    Science.gov (United States)

    Swarts, Daan C; Szczepaniak, Malwina; Sheng, Gang; Chandradoss, Stanley D; Zhu, Yifan; Timmers, Elizabeth M; Zhang, Yong; Zhao, Hongtu; Lou, Jizhong; Wang, Yanli; Joo, Chirlmin; van der Oost, John

    2017-03-16

    Several prokaryotic Argonaute proteins (pAgos) utilize small DNA guides to mediate host defense by targeting invading DNA complementary to the DNA guide. It is unknown how these DNA guides are being generated and loaded onto pAgo. Here, we demonstrate that guide-free Argonaute from Thermus thermophilus (TtAgo) can degrade double-stranded DNA (dsDNA), thereby generating small dsDNA fragments that subsequently are loaded onto TtAgo. Combining single-molecule fluorescence, molecular dynamic simulations, and structural studies, we show that TtAgo loads dsDNA molecules with a preference toward a deoxyguanosine on the passenger strand at the position opposite to the 5' end of the guide strand. This explains why in vivo TtAgo is preferentially loaded with guides with a 5' end deoxycytidine. Our data demonstrate that TtAgo can independently generate and selectively load functional DNA guides.

  15. PROPAGATION CHARACTERISTICS OF HIGH ORDER LONGITUDINAL MODES IN STEEL STRANDS AND THEIR APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    Zenghua Liu; Su Liu; Bin Wu; Yinong Zhang; Cunfu He

    2008-01-01

    Propagation characteristics of high order longitudinal modes of ultrasonic guided waves in seven-wire steel strands are investigated theoretically and experimentally. According to these analysis results, proper longitudinal modes are selected for defect detection in steel strands.Dispersion curves for helical and central wires in a 17.80 mm nominal diameter seven-wire steel strand are numerically obtained firstly, and propagation characteristics of high-order longitudinal modes, such as wave structures, attenuation and dispersion, are analyzed. In experiments, the signals of ultrasonic guided wave at different high frequencies are excited and received at one end of a steel strand by using the same single piezoelectric transducer. The identification of longitudinal modes in the received signals is achieved based on short time Fourier transform. Furthermore,appropriate L(0, 5) mode at 2.54 MHz is chosen for detecting an artificial defect in a helical wire of the steel strand. Results show that high order longitudinal modes in a high frequency range with low dispersion and attenuation whose energy propagates mainly in the center of the wires can be used for defect detection in long range steel strands.

  16. Marine Mammals Ashore: A Field Guide for Strandings. Second Edition

    Science.gov (United States)

    2005-01-01

    South Wales . 147. Pippard, L. 1985. Status of the St. Lawrence River population of beluga . Canadian Field-Naturalist 99:438-450. 148. Pivomnas, A...helpless on land, may occasionally cross the boundary between sea and land without undue risk. A beluga whale may come ashore to rub free a winter’s...inshore periodically (e.g., long-finned pilot whales), during calving or migration (e.g., beluga whales, North Atlantic right whales), or even diurnally

  17. Additive Effects on Asymmetric Catalysis.

    Science.gov (United States)

    Hong, Liang; Sun, Wangsheng; Yang, Dongxu; Li, Guofeng; Wang, Rui

    2016-03-23

    This review highlights a number of additives that can be used to make asymmetric reactions perfect. Without changing other reaction conditions, simply adding additives can lead to improved asymmetric catalysis, such as reduced reaction time, improved yield, or/and increased selectivity.

  18. The asymmetric sandwich theorem

    CERN Document Server

    Simons, Stephen

    2011-01-01

    We discuss the asymmetric sandwich theorem, a generalization of the Hahn-Banach theorem. As applications, we derive various results on the existence of linear functionals that include bivariate, trivariate and quadrivariate generalizations of the Fenchel duality theorem. Most of the results are about affine functions defined on convex subsets of vector spaces, rather than linear functions defined on vector spaces. We consider both results that use a simple boundedness hypothesis (as in Rockafellar's version of the Fenchel duality theorem) and also results that use Baire's theorem (as in the Robinson-Attouch-Brezis version of the Fenchel duality theorem). This paper also contains some new results about metrizable topological vector spaces that are not necessarily locally convex.

  19. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  20. Dynamics of single-stranded DNA tethered to a solid

    Science.gov (United States)

    Radiom, Milad; Paul, Mark R.; Ducker, William A.

    2016-06-01

    Tethering is used to deliver specific biological and industrial functions. For example, single-stranded DNA (ssDNA) is tethered to polymerases and long sequences of double-stranded DNA (dsDNA) during replication, and to solids in DNA microarrays. However, tethering ssDNA to a large object limits not only the available ssDNA conformations, but also the range of time-scales over which the mechanical responses of ssDNA are important. In this work we examine the effect of tethering by measurement of the mechanical response of ssDNA that is tethered at each end to two separate atomic force microscope cantilevers in aqueous solution. Thermal motion of the cantilevers drives the ends of the ssDNA chain at frequencies near 2 kHz. The presence of a tethered molecule makes a large difference to the asymmetric cross-correlation of two cantilevers, which enables resolution of the mechanical properties in our experiments. By analysis of the correlated motion of the cantilevers we extract the friction and stiffness of the ssDNA. We find that the measured friction is much larger than the friction that is usually associated with the unencumbered motion of ssDNA. We also find that the measured relaxation time, ∼30 μs, is much greater than prior measurements of the free-molecule relaxation time. We attribute the difference to the loss of conformational possibilities as a result of constraining the ends of the ssDNA.

  1. Single-stranded heteroduplex intermediates in λ Red homologous recombination

    Directory of Open Access Journals (Sweden)

    Zhang Youming

    2010-07-01

    Full Text Available Abstract Background The Red proteins of lambda phage mediate probably the simplest and most efficient homologous recombination reactions yet described. However the mechanism of dsDNA recombination remains undefined. Results Here we show that the Red proteins can act via full length single stranded intermediates to establish single stranded heteroduplexes at the replication fork. We created asymmetrically digestible dsDNA substrates by exploiting the fact that Redα exonuclease activity requires a 5' phosphorylated end, or is blocked by phosphothioates. Using these substrates, we found that the most efficient configuration for dsDNA recombination occurred when the strand that can prime Okazaki-like synthesis contained both homology regions on the same ssDNA molecule. Furthermore, we show that Red recombination requires replication of the target molecule. Conclusions Hence we propose a new model for dsDNA recombination, termed 'beta' recombination, based on the formation of ssDNA heteroduplexes at the replication fork. Implications of the model were tested using (i an in situ assay for recombination, which showed that recombination generated mixed wild type and recombinant colonies; and (ii the predicted asymmetries of the homology arms, which showed that recombination is more sensitive to non-homologies attached to 5' than 3' ends. Whereas beta recombination can generate deletions in target BACs of at least 50 kb at about the same efficiency as small deletions, the converse event of insertion is very sensitive to increasing size. Insertions up to 3 kb are most efficiently achieved using beta recombination, however at greater sizes, an alternative Red-mediated mechanism(s appears to be equally efficient. These findings define a new intermediate in homologous recombination, which also has practical implications for recombineering with the Red proteins.

  2. Asymmetric positioning of Cas1–2 complex and Integration Host Factor induced DNA bending guide the unidirectional homing of protospacer in CRISPR-Cas type I-E system

    Science.gov (United States)

    Yoganand, K.N.R.; Sivathanu, R.; Nimkar, Siddharth; Anand, B.

    2017-01-01

    CRISPR–Cas system epitomizes prokaryote-specific quintessential adaptive defense machinery that limits the genome invasion of mobile genetic elements. It confers adaptive immunity to bacteria by capturing a protospacer fragment from invading foreign DNA, which is later inserted into the leader proximal end of CRIPSR array and serves as immunological memory to recognize recurrent invasions. The universally conserved Cas1 and Cas2 form an integration complex that is known to mediate the protospacer invasion into the CRISPR array. However, the mechanism by which this protospacer fragment gets integrated in a directional fashion into the leader proximal end is elusive. Here, we employ CRISPR/dCas9 mediated immunoprecipitation and genetic analysis to identify Integration Host Factor (IHF) as an indispensable accessory factor for spacer acquisition in Escherichia coli. Further, we show that the leader region abutting the first CRISPR repeat localizes IHF and Cas1–2 complex. IHF binding to the leader region induces bending by about 120° that in turn engenders the regeneration of the cognate binding site for protospacer bound Cas1–2 complex and brings it in proximity with the first CRISPR repeat. This appears to guide Cas1–2 complex to orient the protospacer invasion towards the leader-repeat junction thus driving the integration in a polarized fashion. PMID:27899566

  3. Hyperchromicity and Strand Separation in Bacterial DNA

    Science.gov (United States)

    Freifelder, David; Davison, Peter F.

    1962-01-01

    Studies of the per cent of strand separation of N14-N15 hybrid coli DNA heated to various temperatures in formaldehyde have shown that the process of strand separation is a function of temperature and formaldehyde concentration and is directly related to the measured hyperchromicity. No strands separate until about 75 per cent of full hyperchromicity is obtained, and even at apparently full hyperchromicity a large fraction of the strands may be held together, possibly by guanine-cytosine-rich regions. PMID:13894962

  4. Numerical Simulation of Capillary Flow in Fan-Shaped Asymmetric Interior Corner Under Microgravity

    Science.gov (United States)

    Yong-Qiang, Li; Wen-Hui, Cao; Ling, Liu

    2017-02-01

    Based on fluid mechanics theories, this research focuses on numerical simulation and analysis of capillary flow under microgravity in fan-shaped asymmetric interior corner. We analyze the effect the contact angle has on rising height in a fan-shaped asymmetric interior corner, and get the Concus-Finn condition the calculation of capillary flow needs to satisfy in fan-shaped asymmetric interior corner. Then we study the effect that different parameters of experimental medium and container configuration has on capillary flow in fan-shaped asymmetric interior corner when Concus-Finn condition is fulfilled. The conclusions of this paper has an important role in guiding the analytic solution of flow in a fan-shaped asymmetric interior corner under microgravity. We can also chose the appropriate experimental medium and design a container based on this paper.

  5. Thermophoresis of single stranded DNA.

    Science.gov (United States)

    Reineck, Philipp; Wienken, Christoph J; Braun, Dieter

    2010-01-01

    The manipulation and analysis of biomolecules in native bulk solution is highly desired; however, few methods are available. In thermophoresis, the thermal analog to electrophoresis, molecules are moved along a microscopic temperature gradient. Its theoretical foundation is still under debate, but practical applications for analytics in biology show considerable potential. Here we measured the thermophoresis of highly diluted single stranded DNA using an all-optical capillary approach. Temperature gradients were created locally by an infrared laser. The thermal depletion of oligonucleotides of between 5 and 50 bases in length were investigated by fluorescence at various salt concentrations. To a good approximation, the previously tested capacitor model describes thermophoresis: the Soret coefficient linearly depends on the Debye length and is proportional to the DNA length to the power of 0.35, dictated by the conformation-based size scaling of the diffusion coefficient. The results form the basis for quantitative DNA analytics using thermophoresis.

  6. Asymmetric Gepner Models (Revisited)

    CERN Document Server

    Gato-Rivera, B

    2010-01-01

    We reconsider a class of heterotic string theories studied in 1989, based on tensor products of N=2 minimal models with asymmetric simple current invariants. We extend this analysis from (2,2) and (1,2) spectra to (0,2) spectra with SO(10) broken to the Standard Model. In the latter case the spectrum must contain fractionally charged particles. We find that in nearly all cases at least some of them are massless. However, we identify a large subclass where the fractional charges are at worst half-integer, and often vector-like. The number of families is very often reduced in comparison to the 1989 results, but there are no new tensor combinations yielding three families. All tensor combinations turn out to fall into two classes: those where the number of families is always divisible by three, and those where it is never divisible by three. We find an empirical rule to determine the class, which appears to extend beyond minimal N=2 tensor products. We observe that distributions of physical quantities such as th...

  7. Control of contact resistance by strand surface coating in 36-strand NbTi CICCs

    NARCIS (Netherlands)

    Nijhuis, Arend; Kate, ten Herman H.J.; Duchateau, Jean-Luc; Decool, Patrick

    2001-01-01

    The stability and AC loss of NbTi cable-in-conduit conductors (CICCs) is largely determined by the interstrand contact resistance (Rc). Rc is predominantly established by the strand surface properties. Five 36-strand CICCs, fully identical except for the plating of the strand surface or the presence

  8. Magnetically Modified Asymmetric Supercapacitors Project

    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....

  9. 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

  10. On Asymmetric Quantum MDS Codes

    CERN Document Server

    Ezerman, Martianus Frederic; Ling, San

    2010-01-01

    Assuming the validity of the MDS Conjecture, the weight distribution of all MDS codes is known. Using a recently-established characterization of asymmetric quantum error-correcting codes, linear MDS codes can be used to construct asymmetric quantum MDS codes with $d_{z} \\geq d_{x}\\geq 2$ for all possible values of length $n$ for which linear MDS codes over $\\F_{q}$ are known to exist.

  11. Asymmetric cation-binding catalysis

    DEFF Research Database (Denmark)

    Oliveira, Maria Teresa; Lee, Jiwoong

    2017-01-01

    and KCN, are selectively bound to the catalyst, providing exceptionally high enantioselectivities for kinetic resolutions, elimination reactions (fluoride base), and Strecker synthesis (cyanide nucleophile). Asymmetric cation-binding catalysis was recently expanded to silicon-based reagents, enabling...... 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...

  12. Microwave-induced inactivation of DNA-based hybrid catalyst in asymmetric catalysis.

    Science.gov (United States)

    Zhao, Hua; Shen, Kai

    2016-03-01

    DNA-based hybrid catalysts have gained strong interests in asymmetric reactions. However, to maintain the high enantioselectivity, these reactions are usually conducted at relatively low temperatures (e.g. DNA-based hybrid catalyst even at low temperatures (such as 5 °C). Circular dichroism (CD) spectra and gel electrophoresis of DNA suggest that microwave exposure degrades DNA molecules and disrupts DNA double-stranded structures, causing changes of DNA-metal ligand binding properties and thus poor DNA catalytic performance.

  13. The Stranding Anomaly as Population Indicator

    DEFF Research Database (Denmark)

    Peltier, Helene; Baagøe, Hans J.; Camphuysen, Kees C.J.;

    2013-01-01

    in space and constant in time. We used a drift model to map stranding probabilities and predict stranding patterns of cetacean carcasses under H0 across the North Sea, the Channel and the Bay of Biscay, for the period 1990–2009. As the most common cetacean occurring in this area, we chose the harbour...

  14. Modelling toehold-mediated RNA strand displacement

    CERN Document Server

    Šulc, Petr; Romano, Flavio; Doye, Jonathan P K; Louis, Ard A

    2014-01-01

    We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperature and make two experimentally testable predictions: that the displacement is faster if the toehold is placed at the 5' end of the substrate and that the displacement slows down with increasing temperature for longer toeholds.

  15. Cetacean strandings in Costa Rica (1966-1999)

    OpenAIRE

    Rodríguez-Fonseca, Javier; Cubero-Pardo,Priscilla

    2014-01-01

    Cetacean strandings in Costa Rica are reported for a period of 33 years, with a total of 35 strandings, 13 species and 247 individuals involved. The vast majority of documented strandings occurred on the Pacific coast and correspond to single individuals (32 and 28 strandings respectively). The highest stranding number was in the period from 1990 to 1999 (n=24). Physeter catodon (cachalot or sperm whale) is the species with the highest frequency of strandings (n=8) and the family Delphinidae ...

  16. Marine mammal strandings in the New Caledonia region, Southwest Pacific.

    Science.gov (United States)

    Borsa, Philippe

    2006-04-01

    Four hundred twenty three marine mammals, in 72 stranding events, were recorded between 1877 and 2005 in New Caledonia, the Loyalty Islands, and Vanuatu in the southwest Pacific. Sixteen species were represented in this count, including: minke whale, Balaenoptera acutorostrata (1 single stranding), sei whale, B. borealis (1 single stranding), blue whale, B. musculus (1 single stranding), humpback whale, Megaptera novaeangliae (2 single strandings), giant sperm whale, Physeter macrocephalus (18 single strandings, 2 pair strandings), pygmy sperm whale, Kogia breviceps (5 single strandings), dwarf sperm whale, K. sima (2 single strandings, 1 triple stranding), Blainville's beaked whale, Mesoplodon densirostris (2 single strandings), short-finned pilot whale, Globicephala macrorhynchus (4 strandings, 56 individuals), melon-headed whale, Peponocephala electra (1 single stranding and 2 mass strandings totalling 231 individuals), common dolphin, Delphinus delphis (1 single stranding), spinner dolphin, Stenella longirostris (1 pair stranding and 2 mass strandings of groups of approximately 30 individuals each), Indian Ocean bottlenose dolphin, Tursiops aduncus (2 single strandings), dugong, Dugong dugon (14 single strandings), and New Zealand fur seal, Arctocephalus forsteri (3 single strandings). A stranded rorqual identified as an Antarctic minke whale (B. bonaerensis), with coloration patterns that did not match known descriptions, was also reported. Sei whale was recorded for the first time in the tropical Southwest Pacific region and Antarctic minke whale, melon-headed whale, and Indian Ocean bottlenose dolphin were recorded for the first time in New Caledonia. Strandings of sperm whales were most frequent in the spring, but also occurred in autumn months, suggesting a seasonal pattern of occurrence possibly related to seasonal migration. One stranded humpback whale bore the scars of a killer whale's attack and one dugong was injured by a shark. Scars left by

  17. Nonlinear effects in asymmetric catalysis.

    Science.gov (United States)

    Satyanarayana, Tummanapalli; Abraham, Susan; Kagan, Henri B

    2009-01-01

    There is a need for the preparation of enantiomerically pure compounds for various applications. An efficient approach to achieve this goal is asymmetric catalysis. The chiral catalyst is usually prepared from a chiral auxiliary, which itself is derived from a natural product or by resolution of a racemic precursor. The use of non-enantiopure chiral auxiliaries in asymmetric catalysis seems unattractive to preparative chemists, since the anticipated enantiomeric excess (ee) of the reaction product should be proportional to the ee value of the chiral auxiliary (linearity). In fact, some deviation from linearity may arise. Such nonlinear effects can be rich in mechanistic information and can be synthetically useful (asymmetric amplification). This Review documents the advances made during the last decade in the use of nonlinear effects in the area of organometallic and organic catalysis.

  18. Asymmetric distances for binary embeddings.

    Science.gov (United States)

    Gordo, Albert; Perronnin, Florent; Gong, Yunchao; Lazebnik, Svetlana

    2014-01-01

    In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes that binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances that are applicable to a wide variety of embedding techniques including locality sensitive hashing (LSH), locality sensitive binary codes (LSBC), spectral hashing (SH), PCA embedding (PCAE), PCAE with random rotations (PCAE-RR), and PCAE with iterative quantization (PCAE-ITQ). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques.

  19. 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...

  20. Alaska Marine Mammal Strandings/Entanglements

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This database represents a summary of information on stranded marine mammals reported to NMFS throughout the State of Alaska in fulfillment of Title IV of the Marine...

  1. Study on Strand Space Model Theory

    Institute of Scientific and Technical Information of China (English)

    JI QingGuang(季庆光); QING SiHan(卿斯汉); ZHOU YongBin(周永彬); FENG DengGuo(冯登国)

    2003-01-01

    The growing interest in the application of formal methods of cryptographic pro-tocol analysis has led to the development of a number of different ways for analyzing protocol. Inthis paper, it is strictly proved that if for any strand, there exists at least one bundle containingit, then an entity authentication protocol is secure in strand space model (SSM) with some smallextensions. Unfortunately, the results of attack scenario demonstrate that this protocol and the Yahalom protocol and its modification are de facto insecure. By analyzing the reasons of failure offormal inference in strand space model, some deficiencies in original SSM are pointed out. In orderto break through these limitations of analytic capability of SSM, the generalized strand space model(GSSM) induced by some protocol is proposed. In this model, some new classes of strands, oraclestrands, high order oracle strands etc., are developed, and some notions are formalized strictly in GSSM, such as protocol attacks, valid protocol run and successful protocol run. GSSM can thenbe used to further analyze the entity authentication protocol. This analysis sheds light on why thisprotocol would be vulnerable while it illustrates that GSSM not only can prove security protocolcorrect, but also can be efficiently used to construct protocol attacks. It is also pointed out thatusing other protocol to attack some given protocol is essentially the same as the case of using themost of protocol itself.

  2. Bubbles in live-stranded dolphins.

    Science.gov (United States)

    Dennison, S; Moore, M J; Fahlman, A; Moore, K; Sharp, S; Harry, C T; Hoppe, J; Niemeyer, M; Lentell, B; Wells, R S

    2012-04-07

    Bubbles in supersaturated tissues and blood occur in beaked whales stranded near sonar exercises, and post-mortem in dolphins bycaught at depth and then hauled to the surface. To evaluate live dolphins for bubbles, liver, kidneys, eyes and blubber-muscle interface of live-stranded and capture-release dolphins were scanned with B-mode ultrasound. Gas was identified in kidneys of 21 of 22 live-stranded dolphins and in the hepatic portal vasculature of 2 of 22. Nine then died or were euthanized and bubble presence corroborated by computer tomography and necropsy, 13 were released of which all but two did not re-strand. Bubbles were not detected in 20 live wild dolphins examined during health assessments in shallow water. Off-gassing of supersaturated blood and tissues was the most probable origin for the gas bubbles. In contrast to marine mammals repeatedly diving in the wild, stranded animals are unable to recompress by diving, and thus may retain bubbles. Since the majority of beached dolphins released did not re-strand it also suggests that minor bubble formation is tolerated and will not lead to clinically significant decompression sickness.

  3. Asymmetric random matrices: What do we need them for?

    CERN Document Server

    Drozdz, Stanislaw; Ioannides, Andreas A; 10.5506/APhysPolB.42.987

    2011-01-01

    Complex systems are typically represented by large ensembles of observations. Correlation matrices provide an efficient formal framework to extract information from such multivariate ensembles and identify in a quantifiable way patterns of activity that are reproducible with statistically significant frequency compared to a reference chance probability, usually provided by random matrices as fundamental reference. The character of the problem and especially the symmetries involved must guide the choice of random matrices to be used for the definition of a baseline reference. For standard correlation matrices this is the Wishart ensemble of symmetric random matrices. The real world complexity however often shows asymmetric information flows and therefore more general correlation matrices are required to adequately capture the asymmetry. Here we first summarize the relevant theoretical concepts. We then present some examples of human brain activity where asymmetric time-lagged correlations are evident and hence...

  4. Implicit knowledge of visual uncertainty guides decisions with asymmetric outcomes

    DEFF Research Database (Denmark)

    Whiteley, Louise Emma; Sahani, Maneesh

    2008-01-01

    Perception is an "inverse problem," in which the state of the world must be inferred from the sensory neural activity that results. However, this inference is both ill-posed (Helmholtz, 1856; Marr, 1982) and corrupted by noise (Green & Swets, 1989), requiring the brain to compute perceptual beliefs...

  5. Synthesis of Asymmetric Propanetriol Analogues

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    From natural tartaric acid, (R)-2-benzyloxy-3-(2-tetrahydropyranyloxy) propanol 3 was designed and synthesized, and (R)-2-benzyloxy-3-(4-methoxybenzyloxy) propanol 7 was prepared in a new method. They can be used as chiral synthons of lysophosphatidic acid and other compounds with asymmetric propanetriol backbone.

  6. Catalytic Asymmetric Bromocyclization of Polyenes.

    Science.gov (United States)

    Samanta, Ramesh C; Yamamoto, Hisashi

    2017-02-01

    The first catalytic asymmetric bromonium ion-induced polyene cyclization has been achieved by using a chiral BINOL-derived thiophosphoramide catalyst and 1,3-dibromo-5,5-dimethylhydantoin as an electrophilic bromine source. Bromocyclization products are obtained in high yields, with good enantiomeric ratios and high diastereoselectivity, and are abundantly found as scaffolds in natural products.

  7. Cetacean strandings in Costa Rica (1966-1999).

    Science.gov (United States)

    Rodríguez-Fonseca, J; Cubero-Pardo, P

    2001-06-01

    Cetacean strandings in Costa Rica are reported for a period of 33 years, with a total of 35 strandings, 13 species and 247 individuals involved. The vast majority of documented strandings occurred on the Pacific coast and correspond to single individuals (32 and 28 strandings respectively). The highest stranding number was in the period from 1990 to 1999 (n = 24). Physeter catodon (cachalot or sperm whale) is the species with the highest frequency of strandings (n = 8) and the family Delphinidae has the majority of species (n = 8) and strandings (n = 22). No other general tendencies were determined with the existing data.

  8. Mechanical properties of rubberwood oriented strand lumber (OSL: The effect of strand length

    Directory of Open Access Journals (Sweden)

    Buhnnum Kyokong

    2005-09-01

    Full Text Available Effect of strand length on mechanical properties (tension, compression and bending of oriented strand lumber (OSL made of rubberwood (Hevea brasiliensis Muell. Arg. was reported. Three strand lengths of 50 mm, 100 mm, and 150 mm with 1 mm thickness and 15 mm width were used. The strands were mixed with 5% pMDI glue (weight basis in a tumble mixer. The OSL specimens were formed by hot pressing process of unidirectionally aligned strands. Average specific gravity and moisture content were 0.76 and 8.34%, respectively. Tension and compression tests were carried out for directions both parallel and perpendicular to grain while bending test was performed only in parallel direction. Ultimate stresses and moduli of elasticity were examined from the stress-strain curves. It was found that for the parallel-to-grain direction, the longer strand OSL gave higher strength. The role of the strand length did not appear for the direction normal to the grain. The relationship between the mechanical properties of OSL and strand length was well described by the modified Hankinson formula.

  9. Stranding of two sperm whales (Physeter macrocephalus) in the "North Sea trap" at Henne Strand, Denmark

    DEFF Research Database (Denmark)

    Hansen, Mette Sif; Alstrup, Aage K. O.; Hansen, Jørgen H.

    2016-01-01

    In February 2014 two male sperm whales (Physeter macrocephalus) stranded at Henne Strand, Denmark. One whale (MCE 1644) was found dead, while the other (MCE 1645) was still alive, but drowned during the high tide. To increase our knowledge of sperm whales, conduct forage investigations, post...

  10. Win-win measurement of stranded costs

    Energy Technology Data Exchange (ETDEWEB)

    Graniere, R.J. [Ohio State Univ., Columbus, OH (United States). National Regulatory Research Inst.

    1998-08-01

    While the underrecovery of stranded costs puts a portion of the utility`s investors` wealth at risk, the overrecovery of these costs causes the utility`s customers to shoulder an unnecessary financial burden. These opposing potential costs associated inevitably with stranded-cost recovery help insure that everyone involved in the production, sale, and use of electric power, for selfish reasons, wants to coordinate on the best measure of these costs. That is, in equilibrium, everyone in the electricity production chain does not want to deviate from a measurement approach that prevents either the overrecovery or underrecovery of stranded costs. An important task, then, is to determine the ad hoc rules that must be appended to ex ante and ex post measures of stranded costs in order to reasonably prevent overrecoveries and underrecoveries. While either ex ante or ex post measures of stranded facilities and costs can be implemented reasonably, appropriately constructed ex post measures are superior, so long as regulators follow a reasonable protocol for the securitization of these costs.

  11. Marine mammal strandings in the New Caledonia region, Southwest Pacific

    OpenAIRE

    Borsa, Philippe

    2006-01-01

    International audience; Four hundred twenty three marine mammals, in 72 stranding events, were recorded between 1877 and 2005 in New Caledonia, the Loyalty Islands, and Vanuatu in the southwest Pacific. Sixteen species were represented in this count, including: minke whale, Balaenoptera acutorostrata (1 single stranding), sei whale, B. borealis (1 single stranding), blue whale, B. musculus (1 single stranding), humpback whale, Megaptera novaeangliae (2 single strandings), giant sperm whale, P...

  12. Asymmetric Multilevel Diversity Coding and Asymmetric Gaussian Multiple Descriptions

    CERN Document Server

    Mohajer, Soheil; Diggavi, Suhas N

    2009-01-01

    We consider the asymmetric multilevel diversity (A-MLD) coding problem, where a set of $2^K-1$ information sources, ordered in a decreasing level of importance, is encoded into $K$ messages (or descriptions). There are $2^K-1$ decoders, each of which has access to a non-empty subset of the encoded messages. Each decoder is required to reproduce the information sources up to a certain importance level depending on the combination of descriptions available to it. We obtain a single letter characterization of the achievable rate region for the 3-description problem. In contrast to symmetric multilevel diversity coding, source-separation coding is not sufficient in the asymmetric case, and ideas akin to network coding need to be used strategically. Based on the intuitions gained in treating the A-MLD problem, we derive inner and outer bounds for the rate region of the asymmetric Gaussian multiple description (MD) problem with three descriptions. Both the inner and outer bounds have a similar geometric structure t...

  13. 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 ......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...

  14. 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.

  15. Terahertz metamaterial with asymmetric transmission

    CERN Document Server

    Singh, R; Menzel, C; Rockstuhl, C; Azad, A K; Cheville, R A; Lederer, F; Zhang, W; Zheludev, N I

    2009-01-01

    We show for the first time that a planar metamaterial, an array of coupled metal split-ring resonators with a unit cell lacking mirror symmetry, exhibits asymmetric transmission of terahertz radiation propagating through it in opposite directions. This intriguing effect, that is compatible with Lorentz reciprocity and time-reversal, depends on a directional difference in conversion efficiency of the incident circularly polarized wave into one of opposite handedness, that is only possible in lossy low-symmetry planar chiral metamaterials. We show that asymmetric transmission is linked to excitation of enantiomerically sensitive plasmons, these are induced charge-field excitations that depend on the mutual handedness of incident wave and metamaterial pattern. Various bands of positive, negative and zero phase and group velocities have been identified indicating the opportunity to develop polarization sensitive negative index and slow light media based on such metamaterials.

  16. 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.

  17. Asymmetrical Γ-Source Inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Poh Chiang, Loh; Blaabjerg, Frede

    2014-01-01

    , inverters with coupled transformers have been introduced, but they usually lead to high turns ratio, and hence many winding turns, at high gain. An alternative would then be the asymmetrical Γ-source inverters proposed in this paper, whose gain is raised by lowering their turns ratio toward unity. The input...... current drawn by the proposed inverters is smoother and, hence, more adaptable by the source. Theories and experimental results have been presented in this paper for validating the concepts proposed....

  18. Up-down asymmetric tokamaks

    CERN Document Server

    Ball, Justin

    2016-01-01

    Bulk toroidal rotation has proven capable of stabilising both dangerous MHD modes and turbulence. In this thesis, we explore a method to drive rotation in large tokamaks: up-down asymmetry in the magnetic equilibrium. We seek to maximise this rotation by finding optimal up-down asymmetric flux surface shapes. First, we use the ideal MHD model to show that low order external shaping (e.g. elongation) is best for creating up-down asymmetric flux surfaces throughout the device. Then, we calculate realistic up-down asymmetric equilibria for input into nonlinear gyrokinetic turbulence analysis. Analytic gyrokinetics shows that, in the limit of fast shaping effects, a poloidal tilt of the flux surface shaping has little effect on turbulent transport. Since up-down symmetric surfaces do not transport momentum, this invariance to tilt implies that devices with mirror symmetry about any line in the poloidal plane will drive minimal rotation. Accordingly, further analytic investigation suggests that non-mirror symmetri...

  19. Double-Stranded Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2001-01-01

    A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  20. SAKAMATA : A tool to avoid whale strandings

    NARCIS (Netherlands)

    Benders, F.P.A.; Beerens, S.P.; Verboom, W.C.

    2002-01-01

    World-wide a concern exists about the influence of man-made noise on marine life, and particularly of high power sonar. Most concern lies with marine mammals that use acoustics for hunting, communication and/or navigation. This concern is fed by recent strandings of whales that could be related to m

  1. SAKAMATA : A tool to avoid whale strandings

    NARCIS (Netherlands)

    Benders, F.P.A.; Beerens, S.P.; Verboom, W.C.

    2004-01-01

    World-wide a concern exists about the influence of man-made noise on marine life, and particularly of high power sonar. Most concern lies with marine mammals that use acoustics for hunting, communication and/or navigation. This concern is fed by recent strandings of whales that could be related to m

  2. Asymmetric Schiff bases derived from diaminomaleonitrile and their metal complexes

    Science.gov (United States)

    Yang, Jianjie; Shi, Rufei; Zhou, Pei; Qiu, Qiming; Li, Hui

    2016-02-01

    Asymmetric Schiff bases, due to its asymmetric structure, can be used as asymmetric catalyst, antibacterial, and mimic molecules during simulate biological processes, etc. In recent years, research on synthesis and properties of asymmetric Schiff bases have become an increase interest of chemists. This review summarizes asymmetric Schiff bases derived from diaminomaleonitrile (DAMN) and DAMN-based asymmetric Schiff bases metal complexes. Applications of DAMN-based asymmetric Schiff bases are also discussed in this review.

  3. Spontaneous baryogenesis from asymmetric inflaton

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Yamada, Masaki [Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; DESY Hamburg (Germany)

    2015-10-15

    We propose a variant scenario of spontaneous baryogenesis from asymmetric inflaton based on current-current interactions between the inflaton and matter fields with a non-zero B-L charge. When the inflaton starts to oscillate around the minimum after inflation, it may lead to excitation of a CP-odd component, which induces an effective chemical potential for the B-L number through the current-current interactions. We study concrete inflation models and show that the spontaneous baryogenesis scenario can be naturally implemented in the chaotic inflation in supergravity.

  4. The asymmetric Goos-H\\"anchen effect

    OpenAIRE

    Araujo, Manoel P.; Carvalho, Silvânia A.; De Leo, Stefano

    2013-01-01

    We show in which conditions optical gaussian beams, propagating throughout an homogeneous dielectric right angle prism, present an asymmetric Goos-H\\"anchen (GH) effect. This asymmetric behavior is seen for incidence at critical angles and happens in the propagation direction of the outgoing beam. The asymmetric GH effect can be also seen as an amplification of the standard GH shift. Due to the fact that it only depends on the ratio between the wavelength and the minimal waist size of the inc...

  5. Review of Composite Asymmetric Spur Gear

    OpenAIRE

    Sandeep C. Dhaduti; Dr. S. G. Sarganachari

    2015-01-01

    Gears made from composite materials are widely used in many power and motion transmission applications. Due to lower weight to stiffness ratio, composite gears may be replaced by conventional material gears in power transmission systems. Design of gears with asymmetric teeth enables to increase load capacity, reduce weight, size and vibration level. This article includes a summary of asymmetric gear design parameters, new developments of asymmetric spur gear and their ...

  6. Controlling stereochemical outcomes of asymmetric processes by catalyst remote molecular functionalizations: chiral diamino-oligothiophenes (DATs) as ligands in asymmetric catalysis.

    Science.gov (United States)

    Albano, Vincenzo Giulio; Bandini, Marco; Barbarella, Giovanna; Melucci, Manuela; Monari, Magda; Piccinelli, Fabio; Tommasi, Simona; Umani-Ronchi, Achille

    2006-01-11

    The synthesis, characterization, and structure-guided application of a new class of highly versatile chiral C(2)-symmetric diamine-oligothiophene ligands in Pd-catalyzed asymmetric transformations are presented. Experimental investigations of the intimate role of pendant pi-conjugate oligothiophenes in determining the catalytic activity of the corresponding chiral Pd complexes are described. Their unusual behavior opens up new routes toward the logical design of finely tuned organometallic catalysts by remote structural functionalizations.

  7. The asymmetric Goos-H\\"anchen effect

    CERN Document Server

    Araujo, Manoel P; De Leo, Stefano

    2014-01-01

    We show in which conditions optical gaussian beams, propagating throughout an homogeneous dielectric right angle prism, present an asymmetric Goos-H\\"anchen (GH) effect. This asymmetric behavior is seen for incidence at critical angles and happens in the propagation direction of the outgoing beam. The asymmetric GH effect can be also seen as an amplification of the standard GH shift. Due to the fact that it only depends on the ratio between the wavelength and the minimal waist size of the incoming gaussian beam, it can be also used to determine one of these parameters. Multiple peaks interference is an additional phenomenon seen in the presence of such asymmetric effects.

  8. Southeast Region Level A Marine Mammal Stranding Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data on marine mammal strandings are collected by the Southeast Marine Mammal Stranding Network. Basic data on the location, species identification, animal...

  9. Asymmetric PCR method in generation of HBV ssDNA for pyrosequencing

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To explore the optimal primer ratio and concentration of asymmetric polymerase chain reaction (A-PCR) in producing hepatitis B virus (HBV) single-stranded DNA (ssDNA) for pyrosequencing. Methods A-PCR was carried out to generate HBV ssDNA with forward to reverse primers of different ratios (50∶1, 100∶1) and concentrations (13.0 pmol/25μL and 0.14 pmol/25μL, 19.5 pmol/25μL and 0.21 pmol/25μL), and the product yield and quality were compared respectively. Results The forward to reverse primer ratio ...

  10. Targeting of single stranded oligonucleotides through metal-induced cyclization of short complementary strands : Targeting of single stranded oligonucleotides

    OpenAIRE

    Freville, Fabrice; Richard, Tristan; Bathany, Katell; Moreau, Serge

    2006-01-01

    International audience; A new strategy to cyclize a short synthetic oligonucleotide on a DNA or a RNA target strand is described. This one relies on a metal-mediated cyclization of short synthetic oligonucleotides conjugated with two chelating 2,2':6',2”-terpyridine moieties at their 3' and 5' ends. Cyclization following metal addition (Zn2+, Fe2+) was demonstrated using UV monitored thermal denaturation experiments, mass spectrometry analysis and gel shift assays. NMR experiments were used t...

  11. Thin lenses of asymmetric power

    Directory of Open Access Journals (Sweden)

    W. F. Harris

    2009-12-01

    Full Text Available It is generally supposed that thin systems, including refracting surfaces and thin lenses, have powers that are necessarily symmetric.  In other words they have powers which can be represented assymmetric dioptric power matrices and in the familar spherocylindrical form used in optometry and ophthalmology.  This paper shows that this is not correct and that it is indeed possible for a thin system to have a power that is not symmetric and which cannot be expressed in spherocylindrical form.  Thin systems of asymmetric power are illustratedby means of a thin lens that is modelled with small prisms and is chosen to have a dioptric power ma-trix that is antisymmetric.  Similar models can be devised for a thin system whose dioptric power matrix is any  2 2 ×  matrix.  Thus any power, symmetric, asymmetric or antisymmetric, is possible for a thin system.  In this sense our understanding of the power of thin systems is now complete.

  12. Excitons in asymmetric quantum wells

    Science.gov (United States)

    Grigoryev, P. S.; Kurdyubov, A. S.; Kuznetsova, M. S.; Ignatiev, I. V.; Efimov, Yu. P.; Eliseev, S. A.; Petrov, V. V.; Lovtcius, V. A.; Shapochkin, P. Yu.

    2016-09-01

    Resonance dielectric response of excitons is studied for the high-quality InGaAs/GaAs heterostructures with wide asymmetric quantum wells (QWs). To highlight effects of the QW asymmetry, we have grown and studied several heterostructures with nominally square QWs as well as with triangle-like QWs. Several quantum confined exciton states are experimentally observed as narrow exciton resonances. A standard approach for the phenomenological analysis of the profiles is generalized by introducing different phase shifts for the light waves reflected from the QWs at different exciton resonances. Good agreement of the phenomenological fit to the experimentally observed exciton spectra for high-quality structures allowed us to reliably obtain parameters of the exciton resonances: the exciton transition energies, the radiative broadenings, and the phase shifts. A direct numerical solution of the Schrödinger equation for the heavy-hole excitons in asymmetric QWs is used for microscopic modeling of the exciton resonances. Remarkable agreement with the experiment is achieved when the effect of indium segregation is taken into account. The segregation results in a modification of the potential profile, in particular, in an asymmetry of the nominally square QWs.

  13. Asymmetric Laguerre-Gaussian beams

    Science.gov (United States)

    Kovalev, A. A.; Kotlyar, V. V.; Porfirev, A. P.

    2016-06-01

    We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redistributed toward peripheral diffraction rings. The projection of the orbital angular momentum (OAM) onto the optical axis is calculated. The OAM is shown to grow quadratically with increasing asymmetry parameter of the aLG beam, which equals the ratio of the shift to the waist radius. Conditions for the OAM becoming equal to the topological charge have been derived. For aLG beams with zero radial index, we have deduced an expression to define the intensity maximum coordinates and shown the crescent-shaped intensity pattern to rotate during propagation. Results of the experimental generation and rotation of aLG beams agree well with theoretical predictions.

  14. Analog Computation by DNA Strand Displacement Circuits.

    Science.gov (United States)

    Song, Tianqi; Garg, Sudhanshu; Mokhtar, Reem; Bui, Hieu; Reif, John

    2016-08-19

    DNA circuits have been widely used to develop biological computing devices because of their high programmability and versatility. Here, we propose an architecture for the systematic construction of DNA circuits for analog computation based on DNA strand displacement. The elementary gates in our architecture include addition, subtraction, and multiplication gates. The input and output of these gates are analog, which means that they are directly represented by the concentrations of the input and output DNA strands, respectively, without requiring a threshold for converting to Boolean signals. We provide detailed domain designs and kinetic simulations of the gates to demonstrate their expected performance. On the basis of these gates, we describe how DNA circuits to compute polynomial functions of inputs can be built. Using Taylor Series and Newton Iteration methods, functions beyond the scope of polynomials can also be computed by DNA circuits built upon our architecture.

  15. Markers of Decompression Stress of Mass Stranded/Live Caught and Released vs. Single Stranded Marine Mammals

    Science.gov (United States)

    2014-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Markers of Decompression Stress of Mass Stranded /Live...Caught and Released vs. Single Stranded Marine Mammals Michael Moore Biology Department Woods Hole Oceanographic Institution Woods Hole, MA 02543...analyze blood samples from captive, wild-caught, and stranded marine mammals in order to compare concentrations of Microparticles (MPs). If confirmed

  16. Asymmetric catalysis : ligand design and microwave acceleration

    OpenAIRE

    Bremberg, Ulf

    2000-01-01

    This thesis deals partly with the design and synthesis ofligands for use in asymmetric catalysis, and partly with theapplication of microwave heating on metal-based asymmetriccatalytic reactions. Enantiomerically pure pyridyl alcohols and bipyridylalcohols were synthesized from the chiral pool for future usein asymmetric catalysis. Lithiated pyridines were reacted withseveral chiral electrophiles, yielding diastereomeric mixturesthat could be separated without the use of resolutiontechniques....

  17. 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...

  18. 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. I...

  19. The Catalytic Asymmetric Intramolecular Stetter Reaction.

    Science.gov (United States)

    de Alaniz, Javier Read; Rovis, Tomislav

    2009-05-01

    This account chronicles our efforts at the development of a catalytic asymmetric Stetter reaction using chiral triazolium salts as small molecule organic catalysts. Advances in the mechanistically related azolium-catalyzed asymmetric benzoin reaction are discussed, particularly as they apply to catalyst design. A chronological treatise of reaction discovery, catalyst optimization and reactivity extension follows.

  20. Condensation on Slippery Asymmetric Bumps

    CERN Document Server

    Park, Kyoo-Chul; He, Neil; Aizenberg, Joanna

    2015-01-01

    Bumps are omnipresent from human skin to the geological structures on planets, which offer distinct advantages in numerous phenomena including structural color, drag reduction, and extreme wettability. Although the topographical parameters of bumps such as radius of curvature of convex regions significantly influence various phenomena including anti-reflective structures and contact time of impacting droplets, the effect of the detailed bump topography on growth and transport of condensates have not been clearly understood. Inspired by the millimetric bumps of the Namib Desert beetle, here we report the identified role of radius of curvature and width of bumps with homogeneous surface wettability in growth rate, coalescence and transport of water droplets. Further rational design of asymmetric convex topography and synergetic combination with slippery coating simultaneously enable self-transport, leading to unseen five-fold higher growth rate and an order of magnitude faster shedding time of droplets compared...

  1. Guided labworks

    DEFF Research Database (Denmark)

    Jacobsen, Lærke Bang

    For the last 40 years physics education research has shown poor learning outcomes of guided labs. Still this is found to be a very used teaching method in the upper secodary schools. This study explains the teacher's choice of guided labs throught the concept of redesign as obstacle dislodgement...

  2. The multiple personalities of Watson and Crick strands

    Directory of Open Access Journals (Sweden)

    Graur Dan

    2011-02-01

    Full Text Available Abstract Background In genetics it is customary to refer to double-stranded DNA as containing a "Watson strand" and a "Crick strand." However, there seems to be no consensus in the literature on the exact meaning of these two terms, and the many usages contradict one another as well as the original definition. Here, we review the history of the terminology and suggest retaining a single sense that is currently the most useful and consistent. Proposal The Saccharomyces Genome Database defines the Watson strand as the strand which has its 5'-end at the short-arm telomere and the Crick strand as its complement. The Watson strand is always used as the reference strand in their database. Using this as the basis of our standard, we recommend that Watson and Crick strand terminology only be used in the context of genomics. When possible, the centromere or other genomic feature should be used as a reference point, dividing the chromosome into two arms of unequal lengths. Under our proposal, the Watson strand is standardized as the strand whose 5'-end is on the short arm of the chromosome, and the Crick strand as the one whose 5'-end is on the long arm. Furthermore, the Watson strand should be retained as the reference (plus strand in a genomic database. This usage not only makes the determination of Watson and Crick unambiguous, but also allows unambiguous selection of reference stands for genomics. Reviewers This article was reviewed by John M. Logsdon, Igor B. Rogozin (nominated by Andrey Rzhetsky, and William Martin.

  3. Amplification methods bias metagenomic libraries of uncultured single-stranded and double-stranded DNA viruses.

    Science.gov (United States)

    Kim, Kyoung-Ho; Bae, Jin-Woo

    2011-11-01

    Investigation of viruses in the environment often requires the amplification of viral DNA before sequencing of viral metagenomes. In this study, two of the most widely used amplification methods, the linker amplified shotgun library (LASL) and multiple displacement amplification (MDA) methods, were applied to a sample from the seawater surface. Viral DNA was extracted from viruses concentrated by tangential flow filtration and amplified by these two methods. 454 pyrosequencing was used to read the metagenomic sequences from different libraries. The resulting taxonomic classifications of the viruses, their functional assignments, and assembly patterns differed substantially depending on the amplification method. Only double-stranded DNA viruses were retrieved from the LASL, whereas most sequences in the MDA library were from single-stranded DNA viruses, and double-stranded DNA viral sequences were minorities. Thus, the two amplification methods reveal different aspects of viral diversity.

  4. The four-transmembrane protein IP39 of Euglena forms strands by a trimeric unit repeat.

    Science.gov (United States)

    Suzuki, Hiroshi; Ito, Yasuyuki; Yamazaki, Yuji; Mineta, Katsuhiko; Uji, Masami; Abe, Kazuhiro; Tani, Kazutoshi; Fujiyoshi, Yoshinori; Tsukita, Sachiko

    2013-01-01

    Euglenoid flagellates have striped surface structures comprising pellicles, which allow the cell shape to vary from rigid to flexible during the characteristic movement of the flagellates. In Euglena gracilis, the pellicular strip membranes are covered with paracrystalline arrays of a major integral membrane protein, IP39, a putative four-membrane-spanning protein with the conserved sequence motif of the PMP-22/EMP/MP20/Claudin superfamily. Here we report the three-dimensional structure of Euglena IP39 determined by electron crystallography. Two-dimensional crystals of IP39 appear to form a striated pattern of antiparallel double-rows in which trimeric IP39 units are longitudinally polymerised, resulting in continuously extending zigzag-shaped lines. Structural analysis revealed an asymmetric molecular arrangement in the trimer, and suggested that at least four different interactions between neighbouring protomers are involved. A combination of such multiple interactions would be important for linear strand formation of membrane proteins in a lipid bilayer.

  5. New insights on single-stranded versus double-stranded DNA library preparation for ancient DNA

    DEFF Research Database (Denmark)

    Wales, Nathan; Carøe, Christian; Sandoval-Velasco, Marcela

    2015-01-01

    An innovative single-stranded DNA (ssDNA) library preparation method has sparked great interest among ancient DNA (aDNA) researchers, especially after reports of endogenous DNA content increases >20-fold in some samples. To investigate the behavior of this method, we generated ss......DNA and conventional double-stranded DNA (dsDNA) libraries from 23 ancient and historic plant and animal specimens. We found ssDNA library preparation substantially increased endogenous content when dsDNA libraries contained...

  6. Asymmetrically Compressed Stereoscopic 3D Videos: Quality Assessment and Rate-Distortion Performance Evaluation.

    Science.gov (United States)

    Wang, Jiheng; Wang, Shiqi; Wang, Zhou

    2017-03-01

    Objective quality assessment of stereoscopic 3D video is challenging but highly desirable, especially in the application of stereoscopic video compression and transmission, where useful quality models are missing, that can guide the critical decision making steps in the selection of mixed-resolution coding, asymmetric quantization, and pre- and post-processing schemes. Here we first carry out subjective quality assessment experiments on two databases that contain various asymmetrically compressed stereoscopic 3D videos obtained from mixed-resolution coding, asymmetric transform-domain quantization coding, their combinations, and the multiple choices of postprocessing techniques. We compare these asymmetric stereoscopic video coding schemes with symmetric coding methods and verify their potential coding gains. We observe a strong systematic bias when using direct averaging of 2D video quality of both views to predict 3D video quality. We then apply a binocular rivalry inspired model to account for the prediction bias, leading to a significantly improved full reference quality prediction model of stereoscopic videos. The model allows us to quantitatively predict the coding gain of different variations of asymmetric video compression, and provides new insight on the development of high efficiency 3D video coding schemes.

  7. HBR guides

    CERN Document Server

    Duarte, Nancy; Dillon, Karen

    2015-01-01

    Master your most pressing professional challenges with this seven-volume set that collects the smartest best practices from leading experts all in one place. "HBR Guide to Better Business Writing" and "HBR Guide to Persuasive Presentations" help you perfect your communication skills; "HBR Guide to Managing Up and Across" and "HBR Guide to Office Politics" show you how to build the best professional relationships; "HBR Guide to Finance Basics for Managers" is the one book you'll ever need to teach you about the numbers; "HBR Guide to Project Management" addresses tough questions such as how to manage stakeholder expectations and how to manage uncertainty in a complex project; and "HBR Guide to Getting the Right Work Done" goes beyond basic productivity tips to teach you how to prioritize and focus on your work. This specially priced set of the most popular books in the series makes a perfect gift for aspiring leaders looking for trusted advice. Arm yourself with the advice you need to succeed on the job, from ...

  8. Asymmetric stem cell division: lessons from Drosophila.

    Science.gov (United States)

    Wu, Pao-Shu; Egger, Boris; Brand, Andrea H

    2008-06-01

    Asymmetric cell division is an important and conserved strategy in the generation of cellular diversity during animal development. Many of our insights into the underlying mechanisms of asymmetric cell division have been gained from Drosophila, including the establishment of polarity, orientation of mitotic spindles and segregation of cell fate determinants. Recent studies are also beginning to reveal the connection between the misregulation of asymmetric cell division and cancer. What we are learning from Drosophila as a model system has implication both for stem cell biology and also cancer research.

  9. On-chip asymmetric microcavity optomechanics.

    Science.gov (United States)

    Soltani, Soheil; Hudnut, Alexa W; Armani, Andrea M

    2016-12-26

    High quality factor (Q) optical resonators have enabled rapid growth in the field of cavity-enhanced, radiation pressure-induced optomechanics. However, because research has focused on axisymmetric devices, the observed regenerative excited mechanical modes are similar. In the present work, a strategy for fabricating high-Q whispering gallery mode microcavities with varying degrees of asymmetry is developed and demonstrated. Due to the combination of high optical Q and asymmetric device design, two previously unobserved modes, the asymmetric cantilever and asymmetric crown mode, are demonstrated with sub-mW thresholds for onset of oscillations. The experimental results are in good agreement with computational modeling predictions.

  10. Regenerating a symmetry in asymmetric dark matter.

    Science.gov (United States)

    Buckley, Matthew R; Profumo, Stefano

    2012-01-06

    Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe.

  11. Absolute Asymmetric Synthesis Using A Cocrystal Approach

    Institute of Scientific and Technical Information of China (English)

    H.Koshima

    2007-01-01

    1 Results Absolute asymmetric synthesis by means of solid-state reaction of chiral crystals self-assembled from achiral molecules is an attractive and promising methodology for asymmetric synthesis because it is not necessary to employ any external chiral source like a chiral catalyst.In order to design reliably absolute asymmetric syntheses in the solid state,it is inevitable to prepare and predict the formation of chiral crystals from achiral compounds.We have prepared a number of chiral cocrystals co...

  12. Asymmetric dark matter in braneworld cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, Michael T.; Whittingham, Ian B., E-mail: Michael.Meehan@my.jcu.edu.au, E-mail: Ian.Whittingham@jcu.edu.au [School of Engineering and Physical Sciences, James Cook University, Townsville, 4811 Australia (Australia)

    2014-06-01

    We investigate the effect of a braneworld expansion era on the relic density of asymmetric dark matter. We find that the enhanced expansion rate in the early universe predicted by the Randall-Sundrum II (RSII) model leads to earlier particle freeze-out and an enhanced relic density. This effect has been observed previously by Okada and Seto (2004) for symmetric dark matter models and here we extend their results to the case of asymmetric dark matter. We also discuss the enhanced asymmetric annihilation rate in the braneworld scenario and its implications for indirect detection experiments.

  13. Enantiopure sulfoxides: recent applications in asymmetric synthesis.

    Science.gov (United States)

    Carreño, M Carmen; Hernández-Torres, Gloria; Ribagorda, María; Urbano, Antonio

    2009-11-07

    Sulfoxides are nowadays recognised as powerful chiral auxiliaries that may participate in a wide range of asymmetric reactions. Their high configurational stability, the existence of several efficient methods allowing the access to both configurations as well as their synthetic versatility are characteristic features offering a tremendous potential to develop new applications. Significant recent advances leading to high asymmetric inductions in carbon-carbon and carbon-oxygen bond forming reactions, and applications of homochiral sulfoxides to atroposelective synthesis and asymmetric catalysis are discussed. New uses of sulfoxides in the design of chiroptical switches are also shown.

  14. Micro/nanofluidic Diode using Asymmetric Ion Concentration Polarization Layer

    Science.gov (United States)

    Sohn, Seoyun; Cho, Inhee; Kim, Sung Jae

    2016-11-01

    Recent developments of ion concentration polarization (ICP) theory would suggest that an over-limiting conductance (OLC) of the device is subject to the morphology of ICP layer and a micro-structure is able to alter the morphology. In this study, we demonstrated an ion rectification resulted only from asymmetric microscale structures, while conventional nanofluidic diode applications have usually employed a nanoscale asymmetry which requires sophisticate and expensive fabrication processes. We designed two dead-end microchannels incorporated with the nanoporous membrane. The difference in width of the microchannels was designed to yield asymmetry to the device. Cyclic voltammetry measurement was conducted to investigate the OLC behaviors on both forward and reverse bias. The diodic characteristics on I-V responses were observed at various ratio of the different microchannel width. In addition, we experimentally verified the logarithmical linearity between the ratios and the rectification ratios of OLC. This quantitative analysis would guide the further application utilizing microscale asymmetric diode device that now can be realized with minimum fabrication endeavors.

  15. Magnetization measurements on LHC superconducting strands

    CERN Document Server

    Le Naour, S; Wolf, R; Puzniak, R; Szewczyk, A; Wisniewski, A; Fikis, H; Foitl, M; Kirchmayr, H

    1999-01-01

    When using superconducting magnets in particle accelerators like the LHC, persistent currents in the superconductor often determine the field quality at injection, where the magnetic field is low. This paper describes magnetization measurements made on LHC cable strands at the Technical University of Vienna and the Institute of Physics of the Polish Academy of Sciences in collaboration with CERN. Measurements were performed at T=2 K and T=4.2 K on more than 50 strands of 7 different manufacturers with NbTi filament diameter between 5 and 7 micrometer. Two different measurement set-ups were used: vibrating sample magnetometer, with a sample length of about 8 mm, and an integrating coil magnetometer, with sample length of about 1 m. The two methods were compared by measuring the same sample. Low field evidence of proximity effect is discussed. Statistics like ratio of the width of the magnetization loop at 4.2 K 2 K, and the initial slope dM/dB after cooldown are presented. Decrease of the magnetization with ti...

  16. Repair of DNA Double-Strand Breaks

    Science.gov (United States)

    Falk, Martin; Lukasova, Emilie; Kozubek, Stanislav

    The genetic information of cells continuously undergoes damage induced by intracellular processes including energy metabolism, DNA replication and transcription, and by environmental factors such as mutagenic chemicals and UV and ionizing radiation. This causes numerous DNA lesions, including double strand breaks (DSBs). Since cells cannot escape this damage or normally function with a damaged genome, several DNA repair mechanisms have evolved. Although most "single-stranded" DNA lesions are rapidly removed from DNA without permanent damage, DSBs completely break the DNA molecule, presenting a real challenge for repair mechanisms, with the highest risk among DNA lesions of incorrect repair. Hence, DSBs can have serious consequences for human health. Therefore, in this chapter, we will refer only to this type of DNA damage. In addition to the biochemical aspects of DSB repair, which have been extensively studied over a long period of time, the spatio-temporal organization of DSB induction and repair, the importance of which was recognized only recently, will be considered in terms of current knowledge and remaining questions.

  17. Hole hopping rates in single strand oligonucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Borrelli, Raffaele [Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, I-10095 Grugliasco, TO (Italy); Capobianco, Amedeo [Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, SA (Italy); Peluso, Andrea, E-mail: apeluso@unisa.it [Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, SA (Italy)

    2014-08-31

    Highlights: • DNA hole transfer rates have been computed. • Delocalized adenine domains significantly affect hole transfer rates in DNA. • Franck–Condon weighted density of state from DFT normal modes. • DNA application in molecular electronics. - Abstract: The rates of hole transfer between guanine and adenine in single strand DNA have been evaluated by using Fermi’s golden rule and Kubo’s generating function approach for the Franck–Condon weighted density of states. The whole sets of the normal modes and vibrational frequencies of the two nucleobases, obtained at DFT/B3LYP level of calculation, have been considered in computations. The results show that in single strand the pyramidalization/planarization mode of the amino groups of both nucleobases plays the major role. At room temperature, the Franck–Condon density of states extends over a wide range of hole site energy difference, 0–1 eV, giving some hints about the design of oligonucleotides of potential technological interest.

  18. Asymmetric dark matter bound state

    Science.gov (United States)

    Bi, Xiao-Jun; Kang, Zhaofeng; Ko, P.; Li, Jinmian; Li, Tianjun

    2017-02-01

    We propose an interesting framework for asymmetric scalar dark matter (ADM), which has novel collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local U (1 )d symmetry which is broken at a low scale and provides a light gauge boson X . The dark gauge coupling is strong and then ADM can annihilate away into X -pair effectively. Therefore, the ADM can form a bound state due to its large self-interaction via X mediation. To explore the collider signature of ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can have a sizable mixing with the heavier Higgs boson, which admits a large cross section of ADMonium production associated with b b ¯. The resulting signature at the LHC depends on the decays of X . In this paper we consider a case of particular interest: p p →b b ¯ +ADMonium followed by ADMonium→2 X →2 e+e- where the electrons are identified as (un)converted photons. It may provide a competitive explanation to heavy di-photon resonance searches at the LHC.

  19. Twin Higgs Asymmetric Dark Matter.

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.

  20. Force on an Asymmetric Capacitor

    CERN Document Server

    Bahder, T B; Bahder, Thomas B.; Fazi, Chris

    2002-01-01

    When a high voltage (~30 kV) is applied to a capacitor whose electrodes have different physical dimensions, the capacitor experiences a net force toward the smaller electrode (Biefeld-Brown effect). We have verified this effect by building four capacitors of different shapes. The effect may have applications to vehicle propulsion and dielectric pumps. We review the history of this effect briefly through the history of patents by Thomas Townsend Brown. 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: ballistic ionic wind and ionic drift. The calculations indicate that ionic wind is at least three orders of magnitude too small to explain the magnitude of the observed force on the capacitor. The ionic drift transport assumption leads to the correct order of magnitude for the force, however, it is difficult to see how ionic dr...

  1. Asymmetric total synthesis of vindoline.

    Science.gov (United States)

    Kato, Daisuke; Sasaki, Yoshikazu; Boger, Dale L

    2010-03-24

    A concise asymmetric total synthesis of (-)-vindoline (1) is detailed based on a tandem intramolecular [4+2]/[3+2] cycloaddition cascade of a 1,3,4-oxadiazole inspired by the natural product structure, in which the tether linking the initiating dienophile and oxadiazole bears a chiral substituent that controls the facial selectivity of the initiating Diels-Alder reaction and sets absolute stereochemistry of the remaining six stereocenters in the cascade cycloadduct. This key reaction introduces three rings and four C-C bonds central to the pentacyclic ring system setting all six stereocenters and introducing essentially all the functionality found in the natural product in a single step. Implementation of the approach also required the development of a unique ring expansion reaction to provide a six-membered ring suitably functionalized for introduction of the Delta (6, 7)-double bond found in the core structure of vindoline and defined our use of a protected hydroxymethyl group as the substituent used to control the stereochemical course of the cycloaddition cascade.

  2. Colostomy Guide

    Science.gov (United States)

    ... Side Effects Managing Cancer-related Side Effects Ostomies Colostomy Guide Colostomy surgery is done for many different diseases and problems. Some colostomies are done because of cancer; others are not. ...

  3. Hypermutability of damaged single-strand DNA formed at double-strand breaks and uncapped telomeres in yeast Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Yong Yang

    2008-11-01

    Full Text Available The major DNA repair pathways operate on damage in double-strand DNA because they use the intact strand as a template after damage removal. Therefore, lesions in transient single-strand stretches of chromosomal DNA are expected to be especially threatening to genome stability. To test this hypothesis, we designed systems in budding yeast that could generate many kilobases of persistent single-strand DNA next to double-strand breaks or uncapped telomeres. The systems allowed controlled restoration to the double-strand state after applying DNA damage. We found that lesions induced by UV-light and methyl methanesulfonate can be tolerated in long single-strand regions and are hypermutagenic. The hypermutability required PCNA monoubiquitination and was largely attributable to translesion synthesis by the error-prone DNA polymerase zeta. In support of multiple lesions in single-strand DNA being a source of hypermutability, analysis of the UV-induced mutants revealed strong strand-specific bias and unexpectedly high frequency of alleles with widely separated multiple mutations scattered over several kilobases. Hypermutability and multiple mutations associated with lesions in transient stretches of long single-strand DNA may be a source of carcinogenesis and provide selective advantage in adaptive evolution.

  4. DNA Strand Breaks, Neurodegeneration and Aging in the Brain

    Science.gov (United States)

    Katyal, Sachin; McKinnon, Peter J.

    2013-01-01

    Defective responses to DNA single- or double-strand breaks can result in neurological disease, underscoring the critical importance of DNA repair for neural homeostasis. Human DNA repair-deficient syndromes are generally congenital, in which brain pathology reflects the consequences of developmentally incurred DNA damage. Although, it is unclear to what degree DNA strand-break repair defects in mature neural cells contributes to disease pathology. However, DNA single-strand breaks are a relatively common lesion which if not repaired can impact cells via interference with transcription. Thus, this lesion, and probably to a lesser extent DNA double strand breaks, may be particularly relevant to aging in the neural cell population. In this review we will examine the consequences of defective DNA strand break repair towards homeostasis in the brain. Further, we also consider the utility of mouse models as reagents to understand the connection between DNA strand breaks and aging in the brain. PMID:18455751

  5. Accurate quantification of microRNA via single strand displacement reaction on DNA origami motif.

    Directory of Open Access Journals (Sweden)

    Jie Zhu

    Full Text Available DNA origami is an emerging technology that assembles hundreds of staple strands and one single-strand DNA into certain nanopattern. It has been widely used in various fields including detection of biological molecules such as DNA, RNA and proteins. MicroRNAs (miRNAs play important roles in post-transcriptional gene repression as well as many other biological processes such as cell growth and differentiation. Alterations of miRNAs' expression contribute to many human diseases. However, it is still a challenge to quantitatively detect miRNAs by origami technology. In this study, we developed a novel approach based on streptavidin and quantum dots binding complex (STV-QDs labeled single strand displacement reaction on DNA origami to quantitatively detect the concentration of miRNAs. We illustrated a linear relationship between the concentration of an exemplary miRNA as miRNA-133 and the STV-QDs hybridization efficiency; the results demonstrated that it is an accurate nano-scale miRNA quantifier motif. In addition, both symmetrical rectangular motif and asymmetrical China-map motif were tested. With significant linearity in both motifs, our experiments suggested that DNA Origami motif with arbitrary shape can be utilized in this method. Since this DNA origami-based method we developed owns the unique advantages of simple, time-and-material-saving, potentially multi-targets testing in one motif and relatively accurate for certain impurity samples as counted directly by atomic force microscopy rather than fluorescence signal detection, it may be widely used in quantification of miRNAs.

  6. Accurate Quantification of microRNA via Single Strand Displacement Reaction on DNA Origami Motif

    Science.gov (United States)

    Lou, Jingyu; Li, Weidong; Li, Sheng; Zhu, Hongxin; Yang, Lun; Zhang, Aiping; He, Lin; Li, Can

    2013-01-01

    DNA origami is an emerging technology that assembles hundreds of staple strands and one single-strand DNA into certain nanopattern. It has been widely used in various fields including detection of biological molecules such as DNA, RNA and proteins. MicroRNAs (miRNAs) play important roles in post-transcriptional gene repression as well as many other biological processes such as cell growth and differentiation. Alterations of miRNAs' expression contribute to many human diseases. However, it is still a challenge to quantitatively detect miRNAs by origami technology. In this study, we developed a novel approach based on streptavidin and quantum dots binding complex (STV-QDs) labeled single strand displacement reaction on DNA origami to quantitatively detect the concentration of miRNAs. We illustrated a linear relationship between the concentration of an exemplary miRNA as miRNA-133 and the STV-QDs hybridization efficiency; the results demonstrated that it is an accurate nano-scale miRNA quantifier motif. In addition, both symmetrical rectangular motif and asymmetrical China-map motif were tested. With significant linearity in both motifs, our experiments suggested that DNA Origami motif with arbitrary shape can be utilized in this method. Since this DNA origami-based method we developed owns the unique advantages of simple, time-and-material-saving, potentially multi-targets testing in one motif and relatively accurate for certain impurity samples as counted directly by atomic force microscopy rather than fluorescence signal detection, it may be widely used in quantification of miRNAs. PMID:23990889

  7. Asymmetric packaging of polymerases within vesicular stomatitis virus

    Energy Technology Data Exchange (ETDEWEB)

    Hodges, Jeffery; Tang, Xiaolin; Landesman, Michael B. [Dept. of Physics and Astronomy, University of Utah (United States); Center for Cell and Genome Science, University of Utah (United States); Ruedas, John B. [Dept. of Biology, San Diego State University (United States); Ghimire, Anil [Dept. of Physics and Astronomy, University of Utah (United States); Gudheti, Manasa V. [Vutara, Inc., Salt Lake City, UT (United States); Dept. of Biology, University of Utah (United States); Perrault, Jacques [Dept. of Biology, San Diego State University (United States); Jorgensen, Erik M. [Howard Hughes Medical Institute (United States); Dept. of Biology, University of Utah (United States); Gerton, Jordan M. [Dept. of Physics and Astronomy, University of Utah (United States); Dept. of Bioengineering, University of Utah (United States); Saffarian, Saveez, E-mail: saffarian@physics.utah.edu [Dept. of Physics and Astronomy, University of Utah (United States); Center for Cell and Genome Science, University of Utah (United States); Dept. of Biology, University of Utah (United States)

    2013-10-18

    Highlights: •The VSV polymerases (L proteins) are localized to the blunt end of the virus. •The VSV phosphoproteins (P proteins) are localized to the blunt end of the virus. •Each VSV virion packages a variable number of P and L proteins. -- Abstract: Vesicular stomatitis virus (VSV) is a prototypic negative sense single-stranded RNA virus. The bullet-shape appearance of the virion results from tightly wound helical turns of the nucleoprotein encapsidated RNA template (N-RNA) around a central cavity. Transcription and replication require polymerase complexes, which include a catalytic subunit L and a template-binding subunit P. L and P are inferred to be in the cavity, however lacking direct observation, their exact position has remained unclear. Using super-resolution fluorescence imaging and atomic force microscopy (AFM) on single VSV virions, we show that L and P are packaged asymmetrically towards the blunt end of the virus. The number of L and P proteins varies between individual virions and they occupy 57 ± 12 nm of the 150 nm central cavity of the virus. Our finding positions the polymerases at the opposite end of the genome with respect to the only transcriptional promoter.

  8. A novel asymmetric synthesis of cinacalcet hydrochloride

    OpenAIRE

    Arava, Veera R; Laxminarasimhulu Gorentla; Pramod K. Dubey

    2012-01-01

    A novel route to asymmetric synthesis of cinacalcet hydrochloride by the application of (R)-tert-butanesulfinamide and regioselective N-alkylation of the naphthyl ethyl sulfinamide intermediate is described.

  9. A novel asymmetric synthesis of cinacalcet hydrochloride

    Directory of Open Access Journals (Sweden)

    Veera R. Arava

    2012-08-01

    Full Text Available A novel route to asymmetric synthesis of cinacalcet hydrochloride by the application of (R-tert-butanesulfinamide and regioselective N-alkylation of the naphthyl ethyl sulfinamide intermediate is described.

  10. A novel asymmetric synthesis of cinacalcet hydrochloride

    Science.gov (United States)

    Gorentla, Laxminarasimhulu; Dubey, Pramod K

    2012-01-01

    Summary A novel route to asymmetric synthesis of cinacalcet hydrochloride by the application of (R)-tert-butanesulfinamide and regioselective N-alkylation of the naphthyl ethyl sulfinamide intermediate is described. PMID:23019473

  11. Catalytic Asymmetric Synthesis of Phosphine Boronates

    NARCIS (Netherlands)

    Hornillos, Valentin; Vila, Carlos; Otten, Edwin; Feringa, Ben L.

    2015-01-01

    The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of ,-unsaturated phosphine oxides catalyzed by a copper bisphosphine complex affords optically active organoboronate esters that bear a vicinal phosphine oxide group in good y

  12. Asymmetric Swiss-cheese brane-worlds

    CERN Document Server

    Gergely, L A; K\\'{e}p\\'{\\i}r\\'{o}, Ibolya

    2006-01-01

    We consider Swiss-cheese brane universes embedded asymmetrically into the bulk. Neither the junction conditions between the Schwarzschild spheres and the sorrounding Friedmann brane regions with cosmological constant $\\Lambda $, nor the evolution of the scale factor are changed with respect to the symmetric case. The universe expands and decelerates forever. The asymmetry however has a drastic influence on the evolution of the cosmological fluid. Instead of the two branches of the symmetric case, in the asymmetric case four branches emerge. Moreover, the future pressure singularity arising in the symmetric case only for huge values of $\\Lambda $ becomes quite generic in the asymmetric case. Such pressure singularities emerge also when $\\Lambda=0$ is set. Then they are due entirely to the asymmetric embedding. For generic values of $\\Lambda $ we introduce a critical value of a suitably defined asymmetry parameter, which separates Swiss-cheese cosmologies with and without pressure singularities.

  13. 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.

  14. 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.

  15. DNA Strand Breaks, Neurodegeneration and Aging in the Brain

    OpenAIRE

    Katyal, Sachin; McKinnon, Peter J

    2008-01-01

    Defective responses to DNA single- or double-strand breaks can result in neurological disease, underscoring the critical importance of DNA repair for neural homeostasis. Human DNA repair-deficient syndromes are generally congenital, in which brain pathology reflects the consequences of developmentally incurred DNA damage. Although, it is unclear to what degree DNA strand-break repair defects in mature neural cells contributes to disease pathology. However, DNA single-strand breaks are a relat...

  16. The multiple personalities of Watson and Crick strands

    OpenAIRE

    Graur Dan; Cartwright Reed A

    2011-01-01

    Abstract Background In genetics it is customary to refer to double-stranded DNA as containing a "Watson strand" and a "Crick strand." However, there seems to be no consensus in the literature on the exact meaning of these two terms, and the many usages contradict one another as well as the original definition. Here, we review the history of the terminology and suggest retaining a single sense that is currently the most useful and consistent. Proposal The Saccharomyces Genome Database defines ...

  17. DOES VOLATILITY RESPOND ASYMMETRIC TO PAST SHOCKS?

    OpenAIRE

    Claudiu Botoc

    2014-01-01

    The main aim of the paper is to examine if the stock market volatility exhibits asymmetric or an asymmetric response to past shocks, for certain CEE countries (Romania,Hungary, Bulgaria, Poland) over the period May 2004 - September 2014. For the stock marketsfrom East Europe the results are in line with the symmetric volatility, i.e. volatility is similaraffected by both positive and negative returns with the same magnitude. For the stock marketsfrom Central Europe the results are consistent ...

  18. Acoustical dead zones and the spatial aggregation of whale strandings.

    Science.gov (United States)

    Sundaram, Bala; Poje, Andrew C; Veit, Richard R; Nganguia, Herve

    2006-02-21

    Cetacean strandings display a marked geographical clustering. We propose a simple, two-dimensional ray-dynamics model of cetacean echolocation to examine the role played by coastline topography in influencing the location and clustering of stranding sites. We find that a number of coastlines known to attract cetacean strandings produce acoustical "Dead Zones" where echolocation signals are severely distorted by purely geometric effects. Using available cetacean stranding data bases from four disparate areas, we show that the geographical clusters in the observations correlate strongly with the regions of distorted echolocation signals as predicted by the model.

  19. Asymmetric cell division and template DNA co-segregation in cancer stem cells

    Directory of Open Access Journals (Sweden)

    Sharon R Pine

    2014-08-01

    Full Text Available During tissue homeostasis, normal stem cells self-renew and repopulate the diverse cell types found within the tissue via a series of carefully controlled symmetric and asymmetric cell divisions. The notion that solid tumors comprise a subset of cancer stem cells with dysregulated self-renewal and excessive symmetric cell divisions has led to numerous studies aimed to elucidate the mechanisms regulating asymmetric cell division under steady-state conditions, during stem cell expansion, and in cancer. In this perspective, we focus on a type of asymmetry that can be established during asymmetric cell division, called non-random co-segregation of template DNA, which has been identified across numerous species, cell types and cancers. We discuss the role of p53 loss in maintaining self-renewal in both normal and malignant cells. We then review our current knowledge of the mechanisms underlying co-segregation of template DNA strands and the stem cell pathways associated with it in normal and cancer stem cells.

  20. Conservative Repair of a Chromosomal Double-Strand Break by Single-Strand DNA through Two Steps of Annealing▿ †

    OpenAIRE

    Storici, Francesca; Snipe, Joyce R.; Chan, Godwin K.; Dmitry A Gordenin; Michael A Resnick

    2006-01-01

    The repair of chromosomal double-strand breaks (DSBs) is essential to normal cell growth, and homologous recombination is a universal process for DSB repair. We explored DSB repair mechanisms in the yeast Saccharomyces cerevisiae using single-strand oligonucleotides with homology to both sides of a DSB. Oligonucleotide-directed repair occurred exclusively via Rad52- and Rad59-mediated single-strand annealing (SSA). Even the SSA domain of human Rad52 provided partial complementation for a null...

  1. Excess single-stranded DNA inhibits meiotic double-strand break repair.

    Directory of Open Access Journals (Sweden)

    Rebecca Johnson

    2007-11-01

    Full Text Available During meiosis, self-inflicted DNA double-strand breaks (DSBs are created by the protein Spo11 and repaired by homologous recombination leading to gene conversions and crossovers. Crossover formation is vital for the segregation of homologous chromosomes during the first meiotic division and requires the RecA orthologue, Dmc1. We analyzed repair during meiosis of site-specific DSBs created by another nuclease, VMA1-derived endonuclease (VDE, in cells lacking Dmc1 strand-exchange protein. Turnover and resection of the VDE-DSBs was assessed in two different reporter cassettes that can repair using flanking direct repeat sequences, thereby obviating the need for a Dmc1-dependent DNA strand invasion step. Access of the single-strand binding complex replication protein A, which is normally used in all modes of DSB repair, was checked in chromatin immunoprecipitation experiments, using antibody against Rfa1. Repair of the VDE-DSBs was severely inhibited in dmc1Delta cells, a defect that was associated with a reduction in the long tract resection required to initiate single-strand annealing between the flanking repeat sequences. Mutants that either reduce Spo11-DSB formation or abolish resection at Spo11-DSBs rescued the repair block. We also found that a replication protein A component, Rfa1, does not accumulate to expected levels at unrepaired single-stranded DNA (ssDNA in dmc1Delta cells. The requirement of Dmc1 for VDE-DSB repair using flanking repeats appears to be caused by the accumulation of large quantities of ssDNA that accumulate at Spo11-DSBs when Dmc1 is absent. We propose that these resected DSBs sequester both resection machinery and ssDNA binding proteins, which in wild-type cells would normally be recycled as Spo11-DSBs repair. The implication is that repair proteins are in limited supply, and this could reflect an underlying mechanism for regulating DSB repair in wild-type cells, providing protection from potentially harmful effects

  2. A methodology to identify stranded generation facilities and estimate stranded costs for Louisiana's electric utility industry

    Science.gov (United States)

    Cope, Robert Frank, III

    1998-12-01

    The electric utility industry in the United States is currently experiencing a new and different type of growing pain. It is the pain of having to restructure itself into a competitive business. Many industry experts are trying to explain how the nation as a whole, as well as individual states, will implement restructuring and handle its numerous "transition problems." One significant transition problem for federal and state regulators rests with determining a utility's stranded costs. Stranded generation facilities are assets which would be uneconomic in a competitive environment or costs for assets whose regulated book value is greater than market value. At issue is the methodology which will be used to estimate stranded costs. The two primary methods are known as "Top-Down" and "Bottom-Up." The "Top-Down" approach simply determines the present value of the losses in revenue as the market price for electricity changes over a period of time into the future. The problem with this approach is that it does not take into account technical issues associated with the generation and wheeling of electricity. The "Bottom-Up" approach computes the present value of specific strandable generation facilities and compares the resulting valuations with their historical costs. It is regarded as a detailed and difficult, but more precise, approach to identifying stranded assets and their associated costs. This dissertation develops a "Bottom-Up" quantitative, optimization-based approach to electric power wheeling within the state of Louisiana. It optimally evaluates all production capabilities and coordinates the movement of bulk power through transmission interconnections of competing companies in and around the state. Sensitivity analysis to this approach is performed by varying seasonal consumer demand, electric power imports, and transmission inter-connection cost parameters. Generation facility economic dispatch and transmission interconnection bulk power transfers, specific

  3. Why double-stranded RNA resists condensation

    Energy Technology Data Exchange (ETDEWEB)

    Tolokh, Igor S.; Pabit, Suzette; Katz, Andrea M.; Chen, Yujie; Drozdetski, Aleksander; Baker, Nathan A.; Pollack, Lois; Onufriev, Alexey

    2014-09-15

    The addition of small amounts of multivalent cations to solutions containing double-stranded DNA leads to attraction between the negatively charged helices and eventually to condensation. Surprisingly, this effect is suppressed in double-stranded RNA, which carries the same charge as the DNA, but assumes a different double helical form. However, additional characterization of short (25 base-pairs) nucleic acid (NA) duplex structures by circular dichroism shows that measured differences in condensation are not solely determined by duplex helical geometry. Here we combine experiment, theory, and atomistic simulations to propose a mechanism that connects the observed variations in condensation of short NA duplexes with the spatial variation of cobalt hexammine (CoHex) binding at the NA duplex surface. The atomistic picture that emerged showed that CoHex distributions around the NA reveals two major NA-CoHex binding modes -- internal and external -- distinguished by the proximity of bound CoHex to the helical axis. Decreasing trends in experimentally observed condensation propensity of the four studied NA duplexes (from B-like form of homopolymeric DNA, to mixed sequence DNA, to DNA:RNA hybrid, to A-like RNA) are explained by the progressive decrease of a single quantity: the fraction of CoHex ions in the external binding mode. Thus, while NA condensation depends on a complex interplay between various structural and sequence features, our coupled experimental and theoretical results suggest a new model in which a single parameter connects the NA condensation propensity with geometry and sequence dependence of CoHex binding.

  4. CRISPR interference directs strand specific spacer acquisition.

    Directory of Open Access Journals (Sweden)

    Daan C Swarts

    Full Text Available BACKGROUND: CRISPR/Cas is a widespread adaptive immune system in prokaryotes. This system integrates short stretches of DNA derived from invading nucleic acids into genomic CRISPR loci, which function as memory of previously encountered invaders. In Escherichia coli, transcripts of these loci are cleaved into small RNAs and utilized by the Cascade complex to bind invader DNA, which is then likely degraded by Cas3 during CRISPR interference. RESULTS: We describe how a CRISPR-activated E. coli K12 is cured from a high copy number plasmid under non-selective conditions in a CRISPR-mediated way. Cured clones integrated at least one up to five anti-plasmid spacers in genomic CRISPR loci. New spacers are integrated directly downstream of the leader sequence. The spacers are non-randomly selected to target protospacers with an AAG protospacer adjacent motif, which is located directly upstream of the protospacer. A co-occurrence of PAM deviations and CRISPR repeat mutations was observed, indicating that one nucleotide from the PAM is incorporated as the last nucleotide of the repeat during integration of a new spacer. When multiple spacers were integrated in a single clone, all spacer targeted the same strand of the plasmid, implying that CRISPR interference caused by the first integrated spacer directs subsequent spacer acquisition events in a strand specific manner. CONCLUSIONS: The E. coli Type I-E CRISPR/Cas system provides resistance against bacteriophage infection, but also enables removal of residing plasmids. We established that there is a positive feedback loop between active spacers in a cluster--in our case the first acquired spacer--and spacers acquired thereafter, possibly through the use of specific DNA degradation products of the CRISPR interference machinery by the CRISPR adaptation machinery. This loop enables a rapid expansion of the spacer repertoire against an actively present DNA element that is already targeted, amplifying the

  5. New insights on single-stranded versus double-stranded DNA library preparation for ancient DNA.

    Science.gov (United States)

    Wales, Nathan; Carøe, Christian; Sandoval-Velasco, Marcela; Gamba, Cristina; Barnett, Ross; Samaniego, José Alfredo; Madrigal, Jazmín Ramos; Orlando, Ludovic; Gilbert, M Thomas P

    2015-12-01

    An innovative single-stranded DNA (ssDNA) library preparation method has sparked great interest among ancient DNA (aDNA) researchers, especially after reports of endogenous DNA content increases >20-fold in some samples. To investigate the behavior of this method, we generated ssDNA and conventional double-stranded DNA (dsDNA) libraries from 23 ancient and historic plant and animal specimens. We found ssDNA library preparation substantially increased endogenous content when dsDNA libraries contained DNA, but this enrichment is less pronounced when dsDNA preparations successfully recover short endogenous DNA fragments (mean size < 70 bp). Our findings can help researchers determine when to utilize the time- and resource-intensive ssDNA library preparation method.

  6. Catalysis of Strand Annealing by Replication Protein A Derives from Its Strand Melting Properties*

    OpenAIRE

    Bartos, Jeremy D.; Willmott, Lyndsay J.; Binz, Sara K.; Wold, Marc S.; Bambara, Robert A.

    2008-01-01

    Eukaryotic DNA-binding protein replication protein A (RPA) has a strand melting property that assists polymerases and helicases in resolving DNA secondary structures. Curiously, previous results suggested that human RPA (hRPA) promotes undesirable recombination by facilitating annealing of flaps produced transiently during DNA replication; however, the mechanism was not understood. We designed a series of substrates, representing displaced DNA flaps generated during ma...

  7. Regulation of Gene Editing Activity Directed by Single-Stranded Oligonucleotides and CRISPR/Cas9 Systems.

    Directory of Open Access Journals (Sweden)

    Pawel Bialk

    Full Text Available Single-stranded DNA oligonucleotides (ssODNs can direct the repair of a single base mutation in human genes. While the regulation of this gene editing reaction has been partially elucidated, the low frequency with which repair occurs has hampered development toward clinical application. In this work a CRISPR/Cas9 complex is employed to induce double strand DNA breakage at specific sites surrounding the nucleotide designated for exchange. The result is a significant elevation in ssODN-directed gene repair, validated by a phenotypic readout. By analysing reaction parameters, we have uncovered restrictions on gene editing activity involving CRISPR/Cas9 complexes. First, ssODNs that hybridize to the non-transcribed strand direct a higher level of gene repair than those that hybridize to the transcribed strand. Second, cleavage must be proximal to the targeted mutant base to enable higher levels of gene editing. Third, DNA cleavage enables a higher level of gene editing activity as compared to single-stranded DNA nicks, created by modified Cas9 (Nickases. Fourth, we calculated the hybridization potential and free energy levels of ssODNs that are complementary to the guide RNA sequences of CRISPRs used in this study. We find a correlation between free energy potential and the capacity of single-stranded oligonucleotides to inhibit specific DNA cleavage activity, thereby indirectly reducing gene editing activity. Our data provide novel information that might be taken into consideration in the design and usage of CRISPR/Cas9 systems with ssODNs for gene editing.

  8. Asymmetric tandem organic solar cells

    Science.gov (United States)

    Howells, Thomas J.

    where it is used to predict the short-circuit current (Jsc) generation of the sub-cells, which is not accessible experimentally. Current-matching is then used to predict the Jsc of the complete tandem device. . As a support to the optical modelling, ellipsometry measurements of thin films of ClAlPc are presented. These films of known thickness are analysed to extract the complex refractive index for use in optical modelling calculations. A dependence of the complex refractive index on film thickness and substrate is also noted. Finally, the external quantum efficiency (EQE) technique is considered as applied to solar cells, and an additional method is proposed to characterise current balancing in asymmetric tandem cells under illumination. This technique is verified experimentally by two separate sets of data..

  9. Strategies underlying RNA silencing suppression by negative strand RNA viruses

    NARCIS (Netherlands)

    Hemmes, J.C.

    2007-01-01

    The research described in this thesis focused on the strategies of negative strand RNA viruses to counteract antiviral RNA silencing. In plants and insects, RNA silencing has been shown to act as a sequence specific antiviral defence mechanism that is characterised by the processing of double strand

  10. A FORMAL SPECIFICATION LANGUAGE FOR DYNAMIC STRAND SPACE MODEL

    Institute of Scientific and Technical Information of China (English)

    刘东喜; 李晓勇; 白英彩

    2002-01-01

    Specification language is used to provide enough information for the model of the cryptographic protocol. This paper first extends strand space model to dynamic strand model, and then a formal specification language for this model is defined by using BNF grammar. Compared with those in literatures, it is simpler because of only concerning the algebraic properties of cryptographic protocols.

  11. Cetaceans stranded in the Netherlands in 2008-2014

    NARCIS (Netherlands)

    Keijl, Guido; Begeman, L.; Hiemstra, S.; IJsseldijk, L.L.; Kamminga, Pepijn

    2016-01-01

    We present a validated list of cetaceans stranded from 2008 up to and including 2014. A total of 4406 cetaceans was found on the Dutch coast during this period, comprising 4346 harbour porpoises (Phocoena phocoena) (98.6% of all strandings) and 59 individuals of twelve other species. The next most n

  12. Cetacean strandings along the coast of Izmir Bay, Turkey

    NARCIS (Netherlands)

    Guclusoy, H.; Veryeri, N.; Cirik, S.

    2004-01-01

    The present paper provides information on the stranding of cetaceans in Izmir Bay, Aegean Sea, between 1992 and 2004. The data were collected opportunistically during sightings and stranding data collection for Monk Seals. A total of 12 cetaceans, namely Bottle-nosed Dolphin, Tursiops truncatus (n=6

  13. Relationship between marine mammal stranding events and offshore earthquakes

    Science.gov (United States)

    Grant, Rachel; Savirina, Anna; Hoppit, Will

    2014-05-01

    The causes of marine mammal stranding events are largely unknown, but may relate to ocean currents, severe weather, anthropogenic noise pollution, and other factors. Large stranding events have been suggested to occur as a result of offshore earthquakes but there is little evidence as yet to support this hypothesis. Stranding events occur in hotspots, which are sometimes areas of high seismic activity, such as Taiwan, and other times, in areas that are removed from seismic zones, such as Cape Cod. We analyse a large and robust dataset of marine mammal stranding data collected off the coast of Washington and Oregon from 1999 to 2010, to look for statistical connections to offshore earthquakes. We looked forward, as well as backward in time from significant seismic events, to ascertain whether stranding occurrences, if connected to earthquakes, are a result of the earthquake preparation period or the earthquake itself. Possible mechanisms are discussed.

  14. Computing in mammalian cells with nucleic acid strand exchange

    Science.gov (United States)

    Groves, Benjamin; Chen, Yuan-Jyue; Zurla, Chiara; Pochekailov, Sergii; Kirschman, Jonathan L.; Santangelo, Philip J.; Seelig, Georg

    2016-03-01

    DNA strand displacement has been widely used for the design of molecular circuits, motors, and sensors in cell-free settings. Recently, it has been shown that this technology can also operate in biological environments, but capabilities remain limited. Here, we look to adapt strand displacement and exchange reactions to mammalian cells and report DNA circuitry that can directly interact with a native mRNA. We began by optimizing the cellular performance of fluorescent reporters based on four-way strand exchange reactions and identified robust design principles by systematically varying the molecular structure, chemistry and delivery method. Next, we developed and tested AND and OR logic gates based on four-way strand exchange, demonstrating the feasibility of multi-input logic. Finally, we established that functional siRNA could be activated through strand exchange, and used native mRNA as programmable scaffolds for co-localizing gates and visualizing their operation with subcellular resolution.

  15. The effect of base pair mismatch on DNA strand displacement

    CERN Document Server

    Broadwater, Bo

    2016-01-01

    DNA strand displacement is a key reaction in DNA homologous recombination and DNA mismatch repair and is also heavily utilized in DNA-based computation and locomotion. Despite its ubiquity in science and engineering, sequence-dependent effects of displacement kinetics have not been extensively characterized. Here, we measured toehold-mediated strand displacement kinetics using single-molecule fluorescence in the presence of a single base pair mismatch. The apparent displacement rate varied significantly when the mismatch was introduced in the invading DNA strand. The rate generally decreased as the mismatch in the invader was encountered earlier in displacement. Our data indicate that a single base pair mismatch in the invader stalls branch migration, and displacement occurs via direct dissociation of the destabilized incumbent strand from the substrate strand. We combined both branch migration and direct dissociation into a model, which we term, the concurrent displacement model, and used the first passage t...

  16. Control of apoptosis by asymmetric cell division.

    Directory of Open Access Journals (Sweden)

    Julia Hatzold

    2008-04-01

    Full Text Available Asymmetric cell division and apoptosis (programmed cell death are two fundamental processes that are important for the development and function of multicellular organisms. We have found that the processes of asymmetric cell division and apoptosis can be functionally linked. Specifically, we show that asymmetric cell division in the nematode Caenorhabditis elegans is mediated by a pathway involving three genes, dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail, that directly control the enzymatic machinery responsible for apoptosis. Interestingly, the MIDA1-like protein GlsA of the alga Volvox carteri, as well as the Snail-related proteins Snail, Escargot, and Worniu of Drosophila melanogaster, have previously been implicated in asymmetric cell division. Therefore, C. elegans dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail may be components of a pathway involved in asymmetric cell division that is conserved throughout the plant and animal kingdoms. Furthermore, based on our results, we propose that this pathway directly controls the apoptotic fate in C. elegans, and possibly other animals as well.

  17. [Development of new methods in asymmetric reactions and their applications].

    Science.gov (United States)

    Node, Manabu

    2002-01-01

    Several novel methods using chiral reagents and biocatalysts for asymmetric reactions are described. Among those reactions, asymmetric reduction via a novel tandem Michael addition/Meerwein-Ponndorf-Verley reduction of acyclic alpha,beta-unsaturated ketones using a chiral mercapto alcohol, asymmetric synthesis of allene-1,3-dicarboxylate via crystallization induced asymmetric transformation, and improved asymmetric nitroolefination of lactones and lactames at alpha-carbon using new chiral reagents were developed. In the reactions using biocatalysts, asymmetric dealkoxycarbonylation of bicyclic beta-keto diesters having sigma-symmetry with lipase or esterase to give optically active beta-keto esters, the asymmetric reduction of bicyclic 1,3-diketones having sigma-symmetry with Baker's yeast to give optically active keto alcohols, and the asymmetric aldol reaction of glycine with threonine aldolase were also developed. The above mentioned products were effectively utilized as chiral building blocks for the asymmetric synthesis of natural products and drugs.

  18. Dc SQUIDs with asymmetric shunt resistors

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, Matthias; Nagel, Joachim; Kemmler, Matthias; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena in LISAplus, Universitaet Tuebingen (Germany); Meckbach, Johannes Maximilian; Ilin, Konstantin; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2013-07-01

    We have investigated asymmetrically shunted Nb/Al-AlO{sub x}/Nb dc SQUIDs. Simulations based on the coupled Langevin equations predict that the optimum energy resolution ε, and thus also the noise performance of such an asymmetric SQUID, can be 3-4 times better than that of its symmetric counterpart. While keeping the total resistance R identical to a comparable symmetric SQUID with R{sup -1} = R{sub 1}{sup -1} + R{sub 2}{sup -1}, we shunted only one of the two Josephson junctions with R = R{sub 1,2}/2. Both types of SQUIDs were characterized with respect to their transport and noise properties at temperature T = 4.2 K, and we compared the experimental results with numerical simulations. Experiments yielded ε ∼ 32 ℎ for an asymmetric SQUID with an inductance L = 22 pH, whereas a comparable symmetric device achieved ε = 110 ℎ.

  19. Asymmetric gear rectifies random robot motion

    Science.gov (United States)

    Li, He; Zhang, H. P.

    2013-06-01

    We experimentally study the dynamics of centimetric robots and their interactions with rotary gears through inelastic collisions. Under the impacts of self-propelled robots, a gear with symmetric teeth diffuses with no preferred direction of motion. An asymmetric gear, however, rectifies random motion of nearby robots which, in return, exert a torque on the gear and drive it into unidirectional motion. Rectification efficiency increases with the degree of gear asymmetry. Our work demonstrates that asymmetric environments can be used to rectify and extract energy from random motion of macroscopic self-propelled particles.

  20. Homogeneous asymmetric catalysis in fragrance chemistry.

    Science.gov (United States)

    Ciappa, Alessandra; Bovo, Sara; Bertoldini, Matteo; Scrivanti, Alberto; Matteoli, Ugo

    2008-06-01

    Opposite enantiomers of a chiral fragrance may exhibit different olfactory activities making a synthesis in high enantiomeric purity commercially and scientifically interesting. Accordingly, the asymmetric synthesis of four chiral odorants, Fixolide, Phenoxanol, Citralis, and Citralis Nitrile, has been investigated with the aim to develop practically feasible processes. In the devised synthetic schemes, the key step that leads to the formation of the stereogenic center is the homogeneous asymmetric hydrogenation of a prochiral olefin. By an appropriate choice of the catalyst and the reaction conditions, Phenoxanol, Citralis, and Citralis Nitrile were obtained in high enantiomeric purity, and odor profiles of the single enantiomers were determined.

  1. Asymmetric catalysis with short-chain peptides.

    Science.gov (United States)

    Lewandowski, Bartosz; Wennemers, Helma

    2014-10-01

    Within this review article we describe recent developments in asymmetric catalysis with peptides. Numerous peptides have been established in the past two decades that catalyze a wide variety of transformations with high stereoselectivities and yields, as well as broad substrate scope. We highlight here catalytically active peptides, which have addressed challenges that had thus far remained elusive in asymmetric catalysis: enantioselective synthesis of atropoisomers and quaternary stereogenic centers, regioselective transformations of polyfunctional substrates, chemoselective transformations, catalysis in-flow and reactions in aqueous environments.

  2. 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.

  3. Integrated asymmetric vertical coupler pressure sensors

    Science.gov (United States)

    Kiyat, Isa; Kocabas, Askin; Akcag, Imran; Aydinli, Atilla

    2004-08-01

    Design and analysis of a novel pressure sensor based on a silicon-on-insulator asymmetric integrated vertical coupler is presented. The coupler is composed of a single mode low index waveguide and a thin silicon slab. Wavelength selective optical modulation of asymmetric vertical coupler is examined in detail. Its potential for sensing applications is highlighted as an integrated optical pressure sensor which can be realized by standard silicon micro-fabrication. Sensitivity of transmission of such couplers on refractive index change of silicon slab ensures that they are good candidates for applications requiring high sensitivities.

  4. Asymmetric localization in disordered Landau bands

    Energy Technology Data Exchange (ETDEWEB)

    Nita, M [Institute of Physics and Technology of Materials, PO Box MG7, Bucharest-Magurele (Romania); Aldea, A [Institute of Physics and Technology of Materials, PO Box MG7, Bucharest-Magurele (Romania); Zittartz, J [Institute of Theoretical Physics, Cologne University, 50937 Cologne (Germany)

    2007-06-06

    We show that, due to band mixing, the eigenstate localization within the disordered Landau bands gets an asymmetric structure: the degree of localization increases in the lower part of the band and decreases in the upper one. The calculation is performed for a two-dimensional lattice with the Anderson disorder potential and we prove that this effect is related to the upper shift of the extended states within the band and is enhanced by the disorder strength. The asymmetric localization and the energy shift disappear when the interband coupling is switched off.

  5. Asymmetric multiscale behavior in PM2.5 time series: Based on asymmetric MS-DFA

    Science.gov (United States)

    Zhang, Chen; Ni, Zhiwei; Ni, Liping

    2016-11-01

    Particulate matter with an aerodynamic diameter of 2.5 mm or less (PM2.5) is one of the most serious air pollution, considered most harmful for people by World Health Organisation. In this paper, we utilized the asymmetric multiscale detrended fluctuation analysis (A-MSDFA) method to explore the existence of asymmetric correlation properties for PM2.5 daily average concentration in two USA cities (Fresno and Los Angeles) and two Chinese cities (Hong Kong and Shanghai), and to assess the properties of these asymmetric correlations. The results show the existences of asymmetric correlations, and the degree of asymmetric for two USA cities is stronger than that of two Chinese cities. Further, most of the local exponent β(n) are smaller than 0.5, which indicates the existence of anti-persistent long-range correlation for PM2.5 time series in four cities. In addition, we reanalyze the asymmetric correlation by the A-MSDFA method with secant rolling windows of different sizes, which can investigate dynamic changes in the multiscale correlation for PM2.5 time series with changing window size. Whatever window sizes, the correlations are asymmetric and display smaller asymmetries at small scales and larger asymmetries at large scales. Moreover, the asymmetries become increasingly weaker with the increase of window sizes.

  6. Asymmetric pallidal neuronal activity in patients with cervical dystonia

    Directory of Open Access Journals (Sweden)

    Christian KE eMoll

    2014-02-01

    Full Text Available The origin of asymmetric clinical manifestation of symptoms in patients suffering from cervical dystonia (CD is hitherto poorly understood. Dysregulated neuronal activity in the basal ganglia has been suggested to have a role in the pathophysiology of CD. Here, we re-assessed the question to what extent relative changes occur in the direct versus indirect basal ganglia pathway in CD, whether these circuit changes are lateralized, and how these alterations relate to CD symptoms. To this end, we recorded ongoing single cell and local field potential (LFP activity from the external (GPe and internal pallidal segment (GPi of thirteen CD patients undergoing microelectrode-guided stereotactic surgery for deep brain stimulation in the GPi. We compared pallidal recordings from CD patients operated under local anaesthesia (LA with those obtained in CD patients operated under general anaesthesia (GA. In awake patients, mean GPe discharge rate (52 Hz was lower than that of GPi (72 Hz. Mean GPi discharge ipsilateral to the side of head turning was higher than contralateral and correlated with torticollis symptom severity. Lateralized differences were absent at the level of the GPe and in recordings from patients operated under GA. Furthermore, in the GPi of CD patients there was a subpopulation of theta-oscillatory cells with unique bursting characteristics. Power and coherence of GPe- and GPi-LFPs were dominated by a theta peak and also exhibited band-specific interhemispheric differences. Strong cross-frequency coupling of low-gamma amplitude to theta phase was a feature of pallidal LFPs recorded under LA, but not GA. These results indicate that CD is associated with an asymmetric pallidal outflow. Based on the finding of symmetric neuronal discharges in the GPe, we propose that an imbalanced interhemispheric direct pathway gain may be involved in CD pathophysiology.

  7. Structure of the EMMPRIN N-terminal domain 1: Dimerization via [beta]-strand swapping

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Jinquan; Teplyakov, Alexey; Obmolova, Galina; Malia, Thomas; Wu, Sheng-Jiun; Beil, Eric; Baker, Audrey; Swencki-Underwood, Bethany; Zhao, Yonghong; Sprenkle, Justin; Dixon, Ken; Sweet, Raymond; Gilliland, Gary L.; (Centocor)

    2010-09-27

    Extracellular matrix metalloproteinase inducer (EMMPRIN), also known as Hab18G, CD147, Basigin, M6, and neurothelin, is a membrane glycoprotein expressed on the surface of various cell types and many cancer cells. EMMPRIN stimulates adjacent fibroblasts and tumor cells to produce matrix metalloproteinases and plays an important role in tumor invasion and metastasis, angiogenesis, spermatogensis and fertilization, cell-cell adhesion and communication, and other biological processes (reviewed in Ref. 1 and references therein). It was demonstrated that the EMMPRIN extracellular domain (ECD), which structurally belongs to the IgG superfamily, can form homo-oligomers in a cis dependent manner and the N-terminal domain 1 (residues 22-101) was necessary and sufficient to mediate this interaction. The crystal structure of the ECD of recombinant human EMMPRIN (Hab18G/CD147) expressed in E. coli was reported at 2.8 {angstrom} resolution (Yu et al. 2008). The construct consists of residues 22-205 of the mature protein and has both an N-terminal IgC2 domain (ND1, residues 22-101) and a C-terminal IgC2 domain (ND2, residues 107-205). The two domains are joined by a five amino acid residue linker that constitutes a flexible hinge between the two domains. The crystal form has four copies of the molecule in the asymmetric unit, each of which has a different inter-domain angle that varies from 121{sup o} to 144{sup o}. The two domains each have a conserved disulfide bridge and both are comprised of two {beta}-sheets formed by strands EBA and GFCC, and DEBA and AGFCC for ND1 and ND2, respectively. Based on the crystal packing in this structure, the authors proposed that lateral packing between the two IgG domains of EMMPRIN ECD represents a potential mechanism for cell adhesion. Here we report the 2.0-{angstrom} crystal structure of the N-terminal domain of EMMPRIN ECD (ND1) expressed in mammalian cells. The overall structure of the domain is very similar to that in the full length

  8. Strand critical current degradation in $Nb_{3}$ Sn Rutherford cables

    CERN Document Server

    Barzi, E; Higley, H C; Scanlan, R M; Yamada, R; Zlobin, A V

    2001-01-01

    Fermilab is developing 11 Tesla superconducting accelerator magnets based on Nb/sub 3/Sn superconductor. Multifilamentary Nb/sub 3/Sn strands produced using the modified jelly roll, internal tin, and powder-in-tube technologies were used for the development and test of the prototype cable. To optimize the cable geometry with respect to the critical current, short samples of Rutherford cable with packing factors in the 85 to 95% range were fabricated and studied. In this paper, the results of measurements of critical current, n-value and RRR made on the round virgin strands and on the strands extracted from the cable samples are presented. (5 refs).

  9. The sense strand pre-cleaved RNA duplex mediates an efficient RNA interference with less off-target and immune response effects.

    Science.gov (United States)

    Lu, Xiaozhao; Yang, Guodong; Zhang, Jie; Fu, Haiyan; Jin, Liang; Wei, Mengying; Wang, Li; Lu, Zifan

    2011-04-01

    RNA interference is an appealing and promising therapeutic approach in cancer and other diseases. Designing novel strategies aiming to increase the efficiency, duration, and reduce the off-target silencing by sense strand is of great significance for its future application clinically. Here, we report that RNA duplex with the sense strand pre-cleaved at the base between base 10 and 11 relative to the 5' end of the antisense strand induced a target-specific RNA silencing effectively. Furthermore, different from the canonical RNA duplex, this novel RNA duplex rarely inhibits the luciferase activity in the reporter, bearing the target sequence corresponding to the sense strand, suggesting a less off-target effects of this novel strategy. Furthermore, the immune response of the novel RNA duplex induced a much milder immune response as seen from the NFkappaB activity. In addition, our newly designed RNA duplex should be easier for preservation than the asymmetric RNA duplex. Our results establish a novel method to design a new class of RNA duplex for improved RNA interference.

  10. Termination of packaging of the bacteriophage lambda chromosome: cosQ is required for nicking the bottom strand of cosN.

    Science.gov (United States)

    Cue, D; Feiss, M

    1998-07-03

    Termination of packaging of the lambda chromosome involves completion of translocation of the DNA into the head shell, and conversion of the translocation complex into a cleavage complex. The cleavage reaction introduces staggered nicks into the downstream cosN to generate the right cohesive end of the chromosome. cosQ, a site adjacent to cosN, was found to be required for nicking the bottom strand of cosN; bottom strand nicking was also sequence-specific for bps at the nick site. Nicking of the top strand of cosN (cosNL) was stimulated by cosQ, but fidelity and efficiency of cosNL nicking were largely dictated by other cos subsites (i.e. cosB and I2). Aberrant top-strand cleavage within cosQ was observed in the absence of I2, and nicking at a site 8 nt 5' to the normal cosNL nick site occurred in the absence of cosB. The presence of cosQ was found to be insufficient to arrest DNA translocation in vivo, indicating that cosQ, per se, is not a packaging stop signal. A model is presented in which the role of cosQ is to depolarize the asymmetric arrangement of terminase protomers in the translocation complex so that protomers are configured to match the 2-fold rotational symmetry of cosN.

  11. THz operation of asymmetric-nanochannel devices

    NARCIS (Netherlands)

    Balocco, C.; Halsall, M.; Vinh, N. Q.; Song, A. M.

    2008-01-01

    The THz spectrum lies between microwaves and the mid-infrared, a region that remains largely unexplored mainly due to the bottleneck issue of lacking compact, solid state, emitters and detectors. Here, we report on a novel asymmetric-nanochannel device, known as the self-switching device, which can

  12. 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.

  13. Dynamic Conditional Correlations for Asymmetric Processes

    NARCIS (Netherlands)

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

    2010-01-01

    textabstractThe paper develops two Dynamic Conditional Correlation (DCC) models, namely the Wishart DCC (WDCC) model and the Matrix-Exponential Conditional Correlation (MECC) model. The paper applies the WDCC approach to the exponential GARCH (EGARCH) and GJR models to propose asymmetric DCC models.

  14. Weak chaos in the asymmetric heavy top

    CERN Document Server

    Barrientos, M; Ranada, A F

    1995-01-01

    We consider the dynamics of the slightly asymmetric heavy top, a non-integrable system obtained from the Lagrange top by breaking the symmetry of its inertia tensor. It shows signs of weak chaos, which we study numerically. We argue that it is a good example for introducing students to non-integrability and chaos. (author)

  15. Catalytic Asymmetric Synthesis of Phosphine Boronates.

    Science.gov (United States)

    Hornillos, Valentín; Vila, Carlos; Otten, Edwin; Feringa, Ben L

    2015-06-26

    The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of α,β-unsaturated phosphine oxides catalyzed by a copper bisphosphine complex affords optically active organoboronate esters that bear a vicinal phosphine oxide group in good yields and high enantiomeric excess. The synthetic utility of the products is demonstrated through stereospecific transformations into multifunctional optically active compounds.

  16. Beam-beam issues in asymmetric colliders

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.A.

    1992-07-01

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

  17. Three dimensional force balance of asymmetric droplets

    Science.gov (United States)

    Kim, Yeseul; Lim, Su Jin; Cho, Kun; Weon, Byung Mook

    2016-11-01

    An equilibrium contact angle of a droplet is determined by a horizontal force balance among vapor, liquid, and solid, which is known as Young's law. Conventional wetting law is valid only for axis-symmetric droplets, whereas real droplets are often asymmetric. Here we show that three-dimensional geometry must be considered for a force balance for asymmetric droplets. By visualizing asymmetric droplets placed on a free-standing membrane in air with X-ray microscopy, we are able to identify that force balances in one side and in other side control pinning behaviors during evaporation of droplets. We find that X-ray microscopy is powerful for realizing the three-dimensional force balance, which would be essential in interpretation and manipulation of wetting, spreading, and drying dynamics for asymmetric droplets. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B01007133).

  18. Asymmetric Hydrogenation of 3-Substituted Pyridinium Salts

    NARCIS (Netherlands)

    Renom-Carrasco, Marc; Gajewski, Piotr; Pignataro, Luca; de Vries, Johannes G.; Piarulli, Umberto; Gennari, Cesare; Lefort, Laurent

    2016-01-01

    The use of an equivalent amount of an organic base leads to high enantiomeric excess in the asymmetric hydrogenation of N-benzylated 3-substituted pyridinium salts into the corresponding piperidines. Indeed, in the presence of Et3N, a Rh-JosiPhos catalyst reduced a range of pyridinium salts with ee

  19. Nucleation Process in Asymmetric Nuclear Matter

    CERN Document Server

    Peres-Menezes, D

    1998-01-01

    An extended version of the non linear Walecka model, with rho mesons and eletromagnetic field is used to investigate the possibility of phase transitions in hot (warm) nuclear matter, giving rise to droplet formation. Surface properties of asymmetric nuclear matter as the droplet surface energy and its thickness are also examined.

  20. Integrated Optical Asymmetric Coupler Pressure Sensor

    Science.gov (United States)

    Kiyat, Isa; Kocabas, Coskun; Aydinli, Atilla

    2004-05-01

    Analysis of a novel pressure sensor based on a silicon-on-insulator (SOI) asymmetric vertical coupler is presented. The integrated optical component is a coupler composed of a single mode (SM) low index waveguide and a thin silicon slab. High sensitivities of about 0.14 rad.kPa-1 should be achieved.

  1. Asymmetric relationships between proteins shape genome evolution.

    NARCIS (Netherlands)

    Notebaart, R.A.; Kensche, P.R.; Huynen, M.A.; Dutilh, B.E.

    2009-01-01

    BACKGROUND: The relationships between proteins are often asymmetric: one protein (A) depends for its function on another protein (B), but the second protein does not depend on the first. In metabolic networks there are multiple pathways that converge into one central pathway. The enzymes in the conv

  2. 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...

  3. 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...

  4. Asymmetric PCR method in generation of HBV ssDNA for pyrosequencing

    Institute of Scientific and Technical Information of China (English)

    Nian-cai Peng; Chun-lin Wang; Li-li Zhang; Mao-li Lu; Zhen-xi Zhang

    2009-01-01

    Objective To explore the optimal primer ratio and concentration of asymmetric polymerase chain reaction (A-PCR) in producing hepatitis B virus (HBV) single-stranded DNA (ssDNA) for pyrosequencing. Methods A-PCR was carried out to generate HBV ssDNA with forward to reverse primers of different ratios (50 : 1, 100 : 1) and concentrations (13. 0 pmol/25μL and 0.14 pmol/25μL, 19. 5 pmol/25μL and 0. 21 pmol/25μL), and the product yield and quality were compared respectively. Results The forward to reverse primer ratio of 50 : 1 provided better yield and concentration of 19. 5 pmol/25μL and 0. 21 pmol//25μL generated a clearer band. Conclusion A simple and feasible method to produce HBV ssDNA for pyrosequencing in batch is established.

  5. 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....

  6. Flow modification in canine intracranial aneurysm model by an asymmetric stent: studies using digital subtraction angiography (DSA) and image-based computational fluid dynamics (CFD) analyses

    Science.gov (United States)

    Hoi, Yiemeng; Ionita, Ciprian N.; Tranquebar, Rekha V.; Hoffmann, Kenneth R.; Woodward, Scott H.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

    2006-03-01

    An asymmetric stent with low porosity patch across the intracranial aneurysm neck and high porosity elsewhere is designed to modify the flow to result in thrombogenesis and occlusion of the aneurysm and yet to reduce the possibility of also occluding adjacent perforator vessels. The purposes of this study are to evaluate the flow field induced by an asymmetric stent using both numerical and digital subtraction angiography (DSA) methods and to quantify the flow dynamics of an asymmetric stent in an in vivo aneurysm model. We created a vein-pouch aneurysm model on the canine carotid artery. An asymmetric stent was implanted at the aneurysm, with 25% porosity across the aneurysm neck and 80% porosity elsewhere. The aneurysm geometry, before and after stent implantation, was acquired using cone beam CT and reconstructed for computational fluid dynamics (CFD) analysis. Both steady-state and pulsatile flow conditions using the measured waveforms from the aneurysm model were studied. To reduce computational costs, we modeled the asymmetric stent effect by specifying a pressure drop over the layer across the aneurysm orifice where the low porosity patch was located. From the CFD results, we found the asymmetric stent reduced the inflow into the aneurysm by 51%, and appeared to create a stasis-like environment which favors thrombus formation. The DSA sequences also showed substantial flow reduction into the aneurysm. Asymmetric stents may be a viable image guided intervention for treating intracranial aneurysms with desired flow modification features.

  7. DNA strand exchange and RecA homologs in meiosis.

    Science.gov (United States)

    Brown, M Scott; Bishop, Douglas K

    2014-12-04

    Homology search and DNA strand-exchange reactions are central to homologous recombination in meiosis. During meiosis, these processes are regulated such that the probability of choosing a homolog chromatid as recombination partner is enhanced relative to that of choosing a sister chromatid. This regulatory process occurs as homologous chromosomes pair in preparation for assembly of the synaptonemal complex. Two strand-exchange proteins, Rad51 and Dmc1, cooperate in regulated homology search and strand exchange in most organisms. Here, we summarize studies on the properties of these two proteins and their accessory factors. In addition, we review current models for the assembly of meiotic strand-exchange complexes and the possible mechanisms through which the interhomolog bias of recombination partner choice is achieved.

  8. Turbulent Flow Validation in the Helios Strand Solver

    Science.gov (United States)

    2014-01-07

    through the three-dimensional stencil of cells surrounding a strand.19 Once the nodal values have been obtained, a Green- Gauss surface integration...line Gauss -Seidel (GS) methods are employed to solve this system, where contributions along strands are collected to form a tridiagonal system. To...Helios Validation V.A.1. Flow over a sphere The first application example is the flow over a sphere at high reynolds number. This is a canonical fluid

  9. Interaction of DAPI with double-stranded ribonucleic acids.

    OpenAIRE

    Manzini, G.; Xodo, L; Barcellona, M L; Quadrifoglio, F

    1985-01-01

    The interaction of DAPI with natural and synthetic double-stranded polyribonucleotides was studied with different optical and calorimetric methods. The results were similar to those obtained previously with double-stranded polydeoxynucleotides, i.e. two interaction modes, the first of which shows high affinity for AU clusters and consequent strong fluorescence enhancement. The results suggest caution in the use of DAPI as selective fluorescent staining agent for DNA in the presence of RNA. A ...

  10. The N-terminal strand modulates immunoglobulin light chain fibrillogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Pozo-Yauner, Luis del, E-mail: ldelpozo@inmegen.gob.mx [Instituto Nacional de Medicina Genómica, Periférico Sur No. 4809, Col. Arenal Tepepan, Delegación Tlalpan, México, D.F. C.P. 14610 (Mexico); Wall, Jonathan S. [Departments of Radiology and Medicine, The University of Tennessee Medical Center, 1924 Alcoa Highway, Knoxville, TN (United States); González Andrade, Martín [Instituto Nacional de Medicina Genómica, Periférico Sur No. 4809, Col. Arenal Tepepan, Delegación Tlalpan, México, D.F. C.P. 14610 (Mexico); Sánchez-López, Rosana [Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa Cuernavaca, Morelos C.P. 62210 (Mexico); Rodríguez-Ambriz, Sandra L. [Centro de Desarrollo de Productos Bióticos, Instituto Politécnico Nacional, Calle CEPROBI No. 8, Col. San Isidro, Yautepec, Morelos C.P. 62731 (Mexico); Pérez Carreón, Julio I. [Instituto Nacional de Medicina Genómica, Periférico Sur No. 4809, Col. Arenal Tepepan, Delegación Tlalpan, México, D.F. C.P. 14610 (Mexico); and others

    2014-01-10

    Highlights: •We evaluated the impact of mutations in the N-terminal strand of 6aJL2 protein. •Mutations destabilized the protein in a position-dependent manner. •Destabilizing mutations accelerated the fibrillogenesis by shortening the lag time. •The effect on the kinetic of fibril elongation by seeding was of different nature. •The N-terminal strand is buried in the fibrillar state of 6aJL2 protein. -- Abstract: It has been suggested that the N-terminal strand of the light chain variable domain (V{sub L}) protects the molecule from aggregation by hindering spurious intermolecular contacts. We evaluated the impact of mutations in the N-terminal strand on the thermodynamic stability and kinetic of fibrillogenesis of the V{sub L} protein 6aJL2. Mutations in this strand destabilized the protein in a position-dependent manner, accelerating the fibrillogenesis by shortening the lag time; an effect that correlated with the extent of destabilization. In contrast, the effect on the kinetics of fibril elongation, as assessed in seeding experiments was of different nature, as it was not directly dependant on the degree of destabilization. This finding suggests different factors drive the nucleation-dependent and elongation phases of light chain fibrillogenesis. Finally, taking advantage of the dependence of the Trp fluorescence upon environment, four single Trp substitutions were made in the N-terminal strand, and changes in solvent exposure during aggregation were evaluated by acrylamide-quenching. The results suggest that the N-terminal strand is buried in the fibrillar state of 6aJL2 protein. This finding suggest a possible explanation for the modulating effect exerted by the mutations in this strand on the aggregation behavior of 6aJL2 protein.

  11. DNA Origami with Double Stranded DNA as a Unified Scaffold

    Science.gov (United States)

    Yang, Yang; Han, Dongran; Nangreave, Jeanette; Liu, Yan; Yan, Hao

    2013-01-01

    Scaffolded DNA origami is a widely used technology for self-assembling precisely structured nanoscale objects that contain a large number of addressable features. Typical scaffolds are long, single strands of DNA (ssDNA) that are folded into distinct shapes through the action of many, short ssDNA staples that are complementary to several different domains of the scaffold. However, sources of long single stranded DNA are scarce, limiting the size and complexity of structures that can be assembled. Here we demonstrated that dsDNA scaffolds can be directly used to fabricate integrated DNA origami structures that incorporate both of the constituent ssDNA molecules. Two basic principles were employed in the design of scaffold folding paths – folding path asymmetry and periodic convergence of the two ssDNA scaffold strands. Asymmetry in the folding path minimizes unwanted complementarity between staples, and incorporating an offset between the folding paths of each ssDNA scaffold strand reduces the number of times that complementary portions of the strands are brought into close proximity with one another, both of which decrease the likelihood of dsDNA scaffold recovery. Meanwhile, the folding paths of the two ssDNA scaffold strands were designed to periodically converge to promote the assembly of a single, unified structure rather than two individual ones. Our results reveal that this basic strategy can be used to reliably assemble integrated DNA nanostructures from dsDNA scaffolds. PMID:22830653

  12. Hearing loss in stranded odontocete dolphins and whales.

    Directory of Open Access Journals (Sweden)

    David Mann

    Full Text Available The causes of dolphin and whale stranding can often be difficult to determine. Because toothed whales rely on echolocation for orientation and feeding, hearing deficits could lead to stranding. We report on the results of auditory evoked potential measurements from eight species of odontocete cetaceans that were found stranded or severely entangled in fishing gear during the period 2004 through 2009. Approximately 57% of the bottlenose dolphins and 36% of the rough-toothed dolphins had significant hearing deficits with a reduction in sensitivity equivalent to severe (70-90 dB or profound (>90 dB hearing loss in humans. The only stranded short-finned pilot whale examined had profound hearing loss. No impairments were detected in seven Risso's dolphins from three different stranding events, two pygmy killer whales, one Atlantic spotted dolphin, one spinner dolphin, or a juvenile Gervais' beaked whale. Hearing impairment could play a significant role in some cetacean stranding events, and the hearing of all cetaceans in rehabilitation should be tested.

  13. Protein-free parallel triple-stranded DNA complex formation

    Science.gov (United States)

    Shchyolkina, A. K.; Timofeev, E. N.; Lysov, Yu. P.; Florentiev, V. L.; Jovin, T. M.; Arndt-Jovin, D. J.

    2001-01-01

    A 14 nt DNA sequence 5′-AGAATGTGGCAAAG-3′ from the zinc finger repeat of the human KRAB zinc finger protein gene ZNF91 bearing the intercalator 2-methoxy,6-chloro,9-amino acridine (Acr) attached to the sugar–phosphate backbone in various positions has been shown to form a specific triple helix (triplex) with a 16 bp hairpin (intramolecular) or a two-stranded (intermolecular) duplex having the identical sequence in the same (parallel) orientation. Intramolecular targets with the identical sequence in the antiparallel orientation and a non-specific target sequence were tested as controls. Apparent binding constants for formation of the triplex were determined by quantitating electrophoretic band shifts. Binding of the single-stranded oligonucleotide probe sequence to the target led to an increase in the fluorescence anisotropy of acridine. The parallel orientation of the two identical sequence segments was confirmed by measurement of fluorescence resonance energy transfer between the acridine on the 5′-end of the probe strand as donor and BODIPY-Texas Red on the 3′-amino group of either strand of the target duplex as acceptor. There was full protection from OsO4-bipyridine modification of thymines in the probe strand of the triplex, in accordance with the presumed triplex formation, which excluded displacement of the homologous duplex strand by the probe–intercalator conjugate. The implications of these results for the existence of protein-independent parallel triplexes are discussed. PMID:11160932

  14. A model capturing novel strand symmetries in bacterial DNA

    Energy Technology Data Exchange (ETDEWEB)

    Sobottka, Marcelo, E-mail: sobottka@mtm.ufsc.br [Departamento de Matematica, Universidade Federal de Santa Catarina (Brazil); Hart, Andrew G., E-mail: ahart@dim.uchile.cl [Departamento de Ingenieria Matematica and Centro de Modelamiento Matematico, Universidad de Chile (Chile)

    2011-07-15

    Highlights: {yields} We propose a simple stochastic model to construct primitive DNA sequences. {yields} The model provide an explanation for Chargaff's second parity rule in primitive DNA sequences. {yields} The model is also used to predict a novel type of strand symmetry in primitive DNA sequences. {yields} We extend the results for bacterial DNA sequences and compare distributional properties intrinsic to the model to statistical estimates from 1049 bacterial genomes. {yields} We find out statistical evidences that the novel type of strand symmetry holds for bacterial DNA sequences. -- Abstract: Chargaff's second parity rule for short oligonucleotides states that the frequency of any short nucleotide sequence on a strand is approximately equal to the frequency of its reverse complement on the same strand. Recent studies have shown that, with the exception of organellar DNA, this parity rule generally holds for double-stranded DNA genomes and fails to hold for single-stranded genomes. While Chargaff's first parity rule is fully explained by the Watson-Crick pairing in the DNA double helix, a definitive explanation for the second parity rule has not yet been determined. In this work, we propose a model based on a hidden Markov process for approximating the distributional structure of primitive DNA sequences. Then, we use the model to provide another possible theoretical explanation for Chargaff's second parity rule, and to predict novel distributional aspects of bacterial DNA sequences.

  15. G-Strands and Peakon Collisions on Diff(R

    Directory of Open Access Journals (Sweden)

    Darryl D. Holm

    2013-03-01

    Full Text Available A G-strand is a map g: R×R→G for a Lie group G that follows from Hamilton's principle for a certain class of G-invariant Lagrangians. Some G-strands on finite-dimensional groups satisfy 1+1 space-time evolutionary equations that admit soliton solutions as completely integrable Hamiltonian systems. For example, the SO(3-strand equations may be regarded physically as integrable dynamics for solitons on a continuous spin chain. Previous work has shown that G-strands for diffeomorphisms on the real line possess solutions with singular support (e.g. peakons. This paper studies collisions of such singular solutions of G-strands when G=Diff(R is the group of diffeomorphisms of the real line R, for which the group product is composition of smooth invertible functions. In the case of peakon-antipeakon collisions, the solution reduces to solving either Laplace's equation or the wave equation (depending on a sign in the Lagrangian and is written in terms of their solutions. We also consider the complexified systems of G-strand equations for G=Diff(R corresponding to a harmonic map g: C→Diff(R and find explicit expressions for its peakon-antipeakon solutions, as well.

  16. Effect of subelement spacing in RRP Nb3Sn strands

    Energy Technology Data Exchange (ETDEWEB)

    Barzi, E.; Turrioni, D.; /Fermilab; Alsharo' a, M.; /MUONS Inc., Batavia; Field, M.; Hong, S.; Parrell, J.; Yamada, R.; /Fermilab; Zhang, Y.; Zlobin, A.; /Fermilab

    2007-10-01

    The Restacked Rod Process (RRP) is the Nb{sub 3}Sn strand technology presently producing the largest critical current densities at 4.2 K and 12 T. However, when subject to plastic deformation, RRP subelements (SE) were found to merge into each other, creating larger filaments with a somewhat continuous barrier. In this case, the strand sees a larger effective filament size, d{sub eff}, and its instability can dramatically increase locally leading to cable quench. To reduce and possibly eliminate this effect, Oxford Instruments Superconducting Technology (OST) developed for FNAL a modified RRP strand design with larger Cu spacing between SE's arranged in a 60/61 array. Strand samples of this design with sizes from 0.7 to 1 mm were first evaluated for transport current properties. A comparison study was then performed between the regular 54/61 and the modified 60/61 design using 0.7 mm round and deformed strands. Finite element modeling of the deformed strands was also performed with ANSYS.

  17. Effects of information feedback on an asymmetrical two-route scenario

    Institute of Scientific and Technical Information of China (English)

    SUN XiaoYan; WANG BingHong; YANG HanXin; WANG QiaoMing; JIANG Rui

    2009-01-01

    In traffic system,a reasonable information feedback can improve road capacity. In this paper,we investigate an asymmetrical two-route scenario in which dynamic information can be generated and displayed on the board to guide drivers. Two improved feedbacks (i.e. improved mean velocity feedback and improved congestion coefficient feedback) are introduced. Simulations show that the average cost is dependent on the vehicle arrival rate and there exists a critical the dynamic vehicles ratio corresponding to the maximum flux. We find that improved con-gestion coefficient can better enhance the system capacity than that of improved mean velocity feedback.

  18. A role for small RNAs in DNA double-strand break repair

    DEFF Research Database (Denmark)

    Wei, W.; Ba, Z.; Wu, Y.;

    2012-01-01

    Eukaryotes have evolved complex mechanisms to repair DNA double-strand breaks (DSBs) through coordinated actions of protein sensors, transducers, and effectors. Here we show that ∼21-nucleotide small RNAs are produced from the sequences in the vicinity of DSB sites in Arabidopsis and in human cells....... We refer to these as diRNAs for DSB-induced small RNAs. In Arabidopsis, the biogenesis of diRNAs requires the PI3 kinase ATR, RNA polymerase IV (Pol IV), and Dicer-like proteins. Mutations in these proteins as well as in Pol V cause significant reduction in DSB repair efficiency. In Arabidopsis, di......RNAs are recruited by Argonaute 2 (AGO2) to mediate DSB repair. Knock down of Dicer or Ago2 in human cells reduces DSB repair. Our findings reveal a conserved function for small RNAs in the DSB repair pathway. We propose that diRNAs may function as guide molecules directing chromatin modifications or the recruitment...

  19. The importance of becoming double-stranded: Innate immunity and the kinetic model of HIV-1 central plus strand synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Poeschla, Eric, E-mail: poeschla.eric@mayo.edu

    2013-06-20

    Central initiation of plus strand synthesis is a conserved feature of lentiviruses and certain other retroelements. This complication of the standard reverse transcription mechanism produces a transient “central DNA flap” in the viral cDNA, which has been proposed to mediate its subsequent nuclear import. This model has assumed that the important feature is the flapped DNA structure itself rather than the process that produces it. Recently, an alternative kinetic model was proposed. It posits that central plus strand synthesis functions to accelerate conversion to the double-stranded state, thereby helping HIV-1 to evade single-strand DNA-targeting antiviral restrictions such as APOBEC3 proteins, and perhaps to avoid innate immune sensor mechanisms. The model is consistent with evidence that lentiviruses must often synthesize their cDNAs when dNTP concentrations are limiting and with data linking reverse transcription and uncoating. There may be additional kinetic advantages for the artificial genomes of lentiviral gene therapy vectors. - Highlights: • Two main functional models for HIV central plus strand synthesis have been proposed. • In one, a transient central DNA flap in the viral cDNA mediates HIV-1 nuclear import. • In the other, multiple kinetic consequences are emphasized. • One is defense against APOBEC3G, which deaminates single-stranded DNA. • Future questions pertain to antiviral restriction, uncoating and nuclear import.

  20. Strength and reliability of Oriented Strand Lumber made from heat-treated Parawood strands

    Directory of Open Access Journals (Sweden)

    Veerapong Chotchuay

    2008-08-01

    Full Text Available This study was carried out to investigate engineering properties of one type of wood composites known as Oriented Strand Lumber (OSL. Heat-treated Parawood strands were used for producing OSL specimens (HOSL and compared to a control one (nonheat-treated or NOSL. The structural application as beams was selected to determine the effect of sheared volume to longitudinal shear strength since shear failure is a critical mode of OSL. The reliability concept was then employedto analyze the data to ensure that OSL structural members can be used for construction safely and economically. The results indicated that mean values of strength of HOSL subjected to axial loading, i.e., compression (39 MPa and tension (36 MPa parallel to the grain as well as bending in the flatwise (59 MPa and edgewise (61 MPa directions were significantly higher than those of NOSL. However, the differences between HOSL and NOSL subjected to normal loading, i.e., compression perpendicular to the grain (26 vs 25 MPa, shear parallel to the grain (4 vs 3 MPa and internal bonding (0.48 vs 0.47 MPa were non-significant. The results of shear strength studies showed that the shear strength ofHOSL beams was higher than that of NOSL beams and regression analysis revealed that the shear strength depended on sheared volume. It showed that shear strength decreased with increasing sheared volume. The results of the reliability analysis indicated that the fitted distribution of the flexural rigidity (EI could be represented well as normal. The coefficient of variation of the fitted EI distribution was found to be within the serviceability limit state required by the building codes. This implies that OSL beams can be used safely as an alternative structural material for wood construction. The safetyfactor and recommended allowable design stresses are also presented.

  1. Enhancing molecule fluorescence with asymmetrical plasmonic antennas.

    Science.gov (United States)

    Lu, Guowei; Liu, Jie; Zhang, Tianyue; Shen, Hongming; Perriat, Pascal; Martini, Matteo; Tillement, Olivier; Gu, Ying; He, Yingbo; Wang, Yuwei; Gong, Qihuang

    2013-07-21

    We propose and justify by the finite-difference time-domain method an efficient strategy to enhance the spontaneous emission of a fluorophore with a multi-resonance plasmonic antenna. The custom-designed asymmetrical antenna consists of two plasmonic nanoparticles with different sizes and is able to couple efficiently to free space light through multiple localized surface plasmon resonances. This design simultaneously permits a large near-field excitation near the antenna as well as a high quantum efficiency, which results in an unusual and significant enhancement of the fluorescence of a single emitter. Such an asymmetrical antenna presents intrinsic advantages over single particle or dimer based antennas made using two identical nanostructures. This promising concept can be exploited in the large domain of light-matter interaction processes involving multiple frequencies.

  2. Design of Asymmetric Peptide Bilayer Membranes.

    Science.gov (United States)

    Li, Sha; Mehta, Anil K; Sidorov, Anton N; Orlando, Thomas M; Jiang, Zhigang; Anthony, Neil R; Lynn, David G

    2016-03-16

    Energetic insights emerging from the structural characterization of peptide cross-β assemblies have enabled the design and construction of robust asymmetric bilayer peptide membranes. Two peptides differing only in their N-terminal residue, phosphotyrosine vs lysine, coassemble as stacks of antiparallel β-sheets with precisely patterned charged lattices stabilizing the bilayer leaflet interface. Either homogeneous or mixed leaflet composition is possible, and both create nanotubes with dense negative external and positive internal solvent exposed surfaces. Cross-seeding peptide solutions with a preassembled peptide nanotube seed leads to domains of different leaflet architecture within single nanotubes. Architectural control over these cross-β assemblies, both across the bilayer membrane and along the nanotube length, provides access to highly ordered asymmetric membranes for the further construction of functional mesoscale assemblies.

  3. Asymmetric dark matter models in SO(10)

    Science.gov (United States)

    Nagata, Natsumi; Olive, Keith A.; Zheng, Jiaming

    2017-02-01

    We systematically study the possibilities for asymmetric dark matter in the context of non-supersymmetric SO(10) models of grand unification. Dark matter stability in SO(10) is guaranteed by a remnant Z2 symmetry which is preserved when the intermediate scale gauge subgroup of SO(10) is broken by a {126} dimensional representation. The asymmetry in the dark matter states is directly generated through the out-of-equilibrium decay of particles around the intermediate scale, or transferred from the baryon/lepton asymmetry generated in the Standard Model sector by leptogenesis. We systematically classify possible asymmetric dark matter candidates in terms of their quantum numbers, and derive the conditions for each case that the observed dark matter density is (mostly) explained by the asymmetry of dark matter particles.

  4. Asymmetric Dark Matter Models in SO(10)

    CERN Document Server

    Nagata, Natsumi; Zheng, Jiaming

    2016-01-01

    We systematically study the possibilities for asymmetric dark matter in the context of non-supersymmetric SO(10) models of grand unification. Dark matter stability in SO(10) is guaranteed by a remnant $\\mathbb{Z}_2$ symmetry which is preserved when the intermediate scale gauge subgroup of SO(10) is broken by a ${\\bf 126}$ dimensional representation. The asymmetry in the dark matter states is directly generated through the out-of-equilibrium decay of particles around the intermediate scale, or transferred from the baryon/lepton asymmetry generated in the Standard Model sector by leptogenesis. We systematically classify possible asymmetric dark matter candidates in terms of their quantum numbers, and derive the conditions for each case that the observed dark matter density is (mostly) explained by the asymmetry of dark matter particles.

  5. Cosmological signatures of time-asymmetric gravity

    CERN Document Server

    Cortês, Marina; Smolin, Lee

    2016-01-01

    We develop the model proposed by Cort\\^es, Gomes & Smolin, to predict cosmological signatures of time-asymmetric extensions of general relativity they proposed recently. Within this class of models the equation of motion of chiral fermions is modified by a torsion term. This term leads to a dispersion law for neutrinos that associates a new time-varying energy with each particle. We find a new neutrino contribution to the Friedmann equation resulting from the torsion term in the Ashtekar connection. In this note we explore the phenomenology of this term and observational consequences for cosmological evolution. We show that constraints on the critical energy density will ordinarily render this term unobservably small, a maximum of order $10^{-25}$ of the neutrino energy density today. However, if the time-asymmetric dark energy is tuned to cancel the cosmological constant, the torsion effect may be a dark matter candidate.

  6. Venture Capital Contracting Under Asymmetric Information

    OpenAIRE

    Jeffrey Trester

    1993-01-01

    The author develops a model of venture capital contracting in which the entrepreneur and venture capitalist contract under symmetric information. A condition of asymmetric information may arise subsequent to the first contract. The author shows that this condition makes debt contracts infeasible and leads to the use of preferred equity contracts. The author notes that discussions of the relation between venture capital and capital structure are rare. This paper expands the literature by addre...

  7. Fluorous Mixture Synthesis of Asymmetric Dendrimers

    Science.gov (United States)

    Jiang, Zhong-Xing; Yu, Yihua Bruce

    2010-01-01

    A divergent fluorous mixture synthesis (FMS) of asymmetric fluorinated dendrimers has been developed. Four generations of fluorinated dendrimers with the same fluorinated moiety were prepared with high efficiency, yield and purity. Comparison of the physicochemical properties of these dendrimers provided valuable information for their application and future optimization. This strategy has not only provided a practical method for the synthesis and purification of dendrimers, but also established the possibility of utilizing the same fluorinated moiety for FMS. PMID:20170088

  8. Asymmetric k-Center with Minimum Coverage

    DEFF Research Database (Denmark)

    Gørtz, Inge Li

    2008-01-01

    In this paper we give approximation algorithms and inapproximability results for various asymmetric k-center with minimum coverage problems. In the k-center with minimum coverage problem, each center is required to serve a minimum number of clients. These problems have been studied by Lim et al. [A....... Lim, B. Rodrigues, F. Wang, Z. Xu, k-center problems with minimum coverage, Theoret. Comput. Sci. 332 (1–3) (2005) 1–17] in the symmetric setting....

  9. New electric field in asymmetric magnetic reconnection.

    Science.gov (United States)

    Malakit, K; Shay, M A; Cassak, P A; Ruffolo, D

    2013-09-27

    We present a theory and numerical evidence for the existence of a previously unexplored in-plane electric field in collisionless asymmetric magnetic reconnection. This electric field, dubbed the "Larmor electric field," is associated with finite Larmor radius effects and is distinct from the known Hall electric field. Potentially, it could be an important indicator for the upcoming Magnetospheric Multiscale mission to locate reconnection sites as we expect it to appear on the magnetospheric side, pointing earthward, at the dayside magnetopause reconnection site.

  10. Asymmetric Information – Adverse Selection Problem

    Directory of Open Access Journals (Sweden)

    Dumitru MARIN

    2007-01-01

    Full Text Available The present paper makes an introduction in the contract theory starting with the definitions of asymmetric information and some of the problems that generate: moral hazard and adverse selection. We provide an insight of the latest empirical studies in adverse selection in different markets. An adverse selection model, based on Rothchild and Stiglitz is also present to give a perspective of the theoretical framework.

  11. Stranding Events of Kogia Whales along the Brazilian Coast.

    Directory of Open Access Journals (Sweden)

    Jailson F Moura

    Full Text Available The genus Kogia, which comprises only two extant species, Kogia sima and Kogia breviceps, represents one of the least known groups of cetaceans in the global ocean. In some coastal regions, however, stranding events of these species have been relatively common over the last decades. Stranding provides the opportunity to investigate the biology of these cetaceans and to explore the epidemiological aspects associated with the mortality of the organisms found on the beach. A number of disturbances (including pelagic fisheries, chemical pollution, boat strikes, and noise pollution have been confirmed to pose a particular threat to the Kogia species. However, no study has yet investigated potential relationships between environmental conditions and stranding events. Here we analyse how a collection of environmental, physical, and biological variables, such as wind, sea surface temperature (SST, water depth, and chlorophyll-a, correlate to Kogia stranding events along the Brazilian coast. The results of our statistical analyses suggest that K. sima is more likely found in warm tropical waters, which provide an explanation for the high frequency of stranding in northeastern Brazilian coast. In contrast, K. breviceps appears to have a preference for temperate and productive waters. Wind speed results to be also an important factor for predicting Kogia strandings in Brazilian coast. Additionally, literature information in combination with our own data and analyses of stomach contents confirms that oceanic cephalopods constitute the primary nutritional source of both Kogia species. By using the available information as a qualitative proxy for habitat preference and feeding ecology, our study provides a novel and comprehensive assessment of Kogia stranding data in relation to environmental conditions along the Brazilian coast.

  12. Role of stranded gas in increasing global gas supplies

    Science.gov (United States)

    Attanasi, E.D.; Freeman, P.A.

    2013-01-01

    This report synthesizes the findings of three regional studies in order to evaluate, at the global scale, the contribution that stranded gas resources can make to global natural gas supplies. Stranded gas, as defined for this study, is natural gas in discovered conventional gas and oil fields that is currently not commercially producible for either physical or economic reasons. The regional studies evaluated the cost of bringing the large volumes of undeveloped gas in stranded gas fields to selected markets. In particular, stranded gas fields of selected Atlantic Basin countries, north Africa, Russia, and central Asia are screened to determine whether the volumes are sufficient to meet Europe’s increasing demand for gas imports. Stranded gas fields in Russia, central Asia, Southeast Asia, and Australia are also screened to estimate development, production, and transport costs and corresponding gas volumes that could be supplied to Asian markets in China, India, Japan, and South Korea. The data and cost analysis presented here suggest that for the European market and the markets examined in Asia, the development of stranded gas provides a way to meet projected gas import demands for the 2020-to-2040 period. Although this is a reconnaissance-type appraisal, it is based on volumes of gas that are associated with individual identified fields. Individual field data were carefully examined. Some fields were not evaluated because current technology was insufficient or it appeared the gas was likely to be held off the export market. Most of the evaluated stranded gas can be produced and delivered to markets at costs comparable to historical prices. Moreover, the associated volumes of gas are sufficient to provide an interim supply while additional technologies are developed to unlock gas diffused in shale and hydrates or while countries transition to making a greater use of renewable energy sources.

  13. Stranding Events of Kogia Whales along the Brazilian Coast.

    Science.gov (United States)

    Moura, Jailson F; Acevedo-Trejos, Esteban; Tavares, Davi C; Meirelles, Ana C O; Silva, Cristine P N; Oliveira, Larissa R; Santos, Roberta A; Wickert, Janaína C; Machado, Rodrigo; Siciliano, Salvatore; Merico, Agostino

    2016-01-01

    The genus Kogia, which comprises only two extant species, Kogia sima and Kogia breviceps, represents one of the least known groups of cetaceans in the global ocean. In some coastal regions, however, stranding events of these species have been relatively common over the last decades. Stranding provides the opportunity to investigate the biology of these cetaceans and to explore the epidemiological aspects associated with the mortality of the organisms found on the beach. A number of disturbances (including pelagic fisheries, chemical pollution, boat strikes, and noise pollution) have been confirmed to pose a particular threat to the Kogia species. However, no study has yet investigated potential relationships between environmental conditions and stranding events. Here we analyse how a collection of environmental, physical, and biological variables, such as wind, sea surface temperature (SST), water depth, and chlorophyll-a, correlate to Kogia stranding events along the Brazilian coast. The results of our statistical analyses suggest that K. sima is more likely found in warm tropical waters, which provide an explanation for the high frequency of stranding in northeastern Brazilian coast. In contrast, K. breviceps appears to have a preference for temperate and productive waters. Wind speed results to be also an important factor for predicting Kogia strandings in Brazilian coast. Additionally, literature information in combination with our own data and analyses of stomach contents confirms that oceanic cephalopods constitute the primary nutritional source of both Kogia species. By using the available information as a qualitative proxy for habitat preference and feeding ecology, our study provides a novel and comprehensive assessment of Kogia stranding data in relation to environmental conditions along the Brazilian coast.

  14. 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.

  15. Asymmetric Conditional Volatility in International Stock Markets

    CERN Document Server

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

    2006-01-01

    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 S&P 500, FTSE100, 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 chan...

  16. Multiple Traveling Salesmen in Asymmetric Metrics

    CERN Document Server

    Friggstad, Zachary

    2011-01-01

    We consider some generalizations of the Asymmetric Traveling Salesman Path problem. Suppose we have an asymmetric metric G = (V,A) with two distinguished nodes s,t. We are also given a positive integer k. The goal is to find k paths of minimum total cost from s to t whose union spans all nodes. We call this the k-Person Asymmetric Traveling Salesmen Path problem (k-ATSPP). Our main result for k-ATSPP is a bicriteria approximation that, for some parameter b >= 1 we may choose, finds between k and k + k/b paths of total length O(b log |V|) times the optimum value of an LP relaxation based on the Held-Karp relaxation for the Traveling Salesman problem. On one extreme this is an O(log |V|)-approximation that uses up to 2k paths and on the other it is an O(k log |V|)-approximation that uses exactly k paths. Next, we consider the case where we have k pairs of nodes (s_1,t_1), ..., (s_k,t_k). The goal is to find an s_i-t_i path for every pair such that each node of G lies on at least one of these paths. Simple appro...

  17. Traceless Synthesis of Asymmetrically Modified Bivalent Nucleosomes.

    Science.gov (United States)

    Lechner, Carolin C; Agashe, Ninad D; Fierz, Beat

    2016-02-18

    Nucleosomes carry extensive post-translational modifications (PTMs), which results in complex modification patterns that are involved in epigenetic signaling. Although two copies of each histone coexist in a nucleosome, they may not carry the same PTMs and are often differently modified (asymmetric). In bivalent domains, a chromatin signature prevalent in embryonic stem cells (ESCs), namely H3 methylated at lysine 4 (H3K4me3), coexists with H3K27me3 in asymmetric nucleosomes. We report a general, modular, and traceless method for producing asymmetrically modified nucleosomes. We further show that in bivalent nucleosomes, H3K4me3 inhibits the activity of the H3K27-specific lysine methyltransferase (KMT) polycomb repressive complex 2 (PRC2) solely on the same histone tail, whereas H3K27me3 stimulates PRC2 activity across tails, thereby partially overriding the H3K4me3-mediated repressive effect. To maintain bivalent domains in ESCs, PRC2 activity must thus be locally restricted or reversed.

  18. SPECT using asymmetric pinholes with truncated projections

    Energy Technology Data Exchange (ETDEWEB)

    Lin Jianyu; Meikle, Steven R, E-mail: jianyu.lin@curtin.edu.au [Ramaciotti Imaging Centre, Brain and Mind Research Institute, University of Sydney (Australia)

    2011-07-07

    Tomographic systems employing truncated projections have been developed for parallel and fan beam collimation and for cone beam CT but the idea has not been extensively explored in pinhole single photon emission computed tomography (SPECT). In this paper, we explore the sampling requirements and system performance of SPECT systems with asymmetric pinhole collimators and truncated projections. We demonstrate that complete 3D sampling can be achieved by using multiple detectors with truncated asymmetric pinholes, offset axially from each other, and a spiral orbit. The use of truncated projections can be exploited in the design of pinhole SPECT systems by moving the pinholes closer to the subject, resulting in increased sensitivity and improved spatial resolution. Truncated and untruncated pinhole systems were evaluated using the contrast-to-noise ratio (CNR) calculated from the linearized local impulse response as a figure of merit. The CNR for the truncated pinhole system was up to 60% greater than that for the untruncated system at matched resolution for a source voxel near the centre of a uniform phantom and 30% greater at the edge. We conclude that an object can be reconstructed from asymmetric pinholes with truncated projections, which leads to potentially important design considerations and applications in single- and multi-pinhole SPECT.

  19. Marine Mammal Necropsy: An Introductory Guide for Stranding Responders and Field Biologists

    Science.gov (United States)

    2007-09-01

    lung, liver, spleen, lymph nodes and brain. Additional samples may include skin, mucocutaneous junctions or the oral cavity, rectum, and urogenital tract... urogenital tracts. Consult the working researcher or lab in advance for re- quired tissues. A small amount of tissue is needed and can be collected in...the gastro-intestinal system do not contaminate other tissues. 38 Tracheobronchial ( TB ) Lymph Node: The TB lymph node is located proximal to the

  20. Packaging signals in two single-stranded RNA viruses imply a conserved assembly mechanism and geometry of the packaged genome.

    Science.gov (United States)

    Dykeman, Eric C; Stockley, Peter G; Twarock, Reidun

    2013-09-09

    The current paradigm for assembly of single-stranded RNA viruses is based on a mechanism involving non-sequence-specific packaging of genomic RNA driven by electrostatic interactions. Recent experiments, however, provide compelling evidence for sequence specificity in this process both in vitro and in vivo. The existence of multiple RNA packaging signals (PSs) within viral genomes has been proposed, which facilitates assembly by binding coat proteins in such a way that they promote the protein-protein contacts needed to build the capsid. The binding energy from these interactions enables the confinement or compaction of the genomic RNAs. Identifying the nature of such PSs is crucial for a full understanding of assembly, which is an as yet untapped potential drug target for this important class of pathogens. Here, for two related bacterial viruses, we determine the sequences and locations of their PSs using Hamiltonian paths, a concept from graph theory, in combination with bioinformatics and structural studies. Their PSs have a common secondary structure motif but distinct consensus sequences and positions within the respective genomes. Despite these differences, the distributions of PSs in both viruses imply defined conformations for the packaged RNA genomes in contact with the protein shell in the capsid, consistent with a recent asymmetric structure determination of the MS2 virion. The PS distributions identified moreover imply a preferred, evolutionarily conserved assembly pathway with respect to the RNA sequence with potentially profound implications for other single-stranded RNA viruses known to have RNA PSs, including many animal and human pathogens.

  1. Accurate strand-specific quantification of viral RNA.

    Directory of Open Access Journals (Sweden)

    Nicole E Plaskon

    Full Text Available The presence of full-length complements of viral genomic RNA is a hallmark of RNA virus replication within an infected cell. As such, methods for detecting and measuring specific strands of viral RNA in infected cells and tissues are important in the study of RNA viruses. Strand-specific quantitative real-time PCR (ssqPCR assays are increasingly being used for this purpose, but the accuracy of these assays depends on the assumption that the amount of cDNA measured during the quantitative PCR (qPCR step accurately reflects amounts of a specific viral RNA strand present in the RT reaction. To specifically test this assumption, we developed multiple ssqPCR assays for the positive-strand RNA virus o'nyong-nyong (ONNV that were based upon the most prevalent ssqPCR assay design types in the literature. We then compared various parameters of the ONNV-specific assays. We found that an assay employing standard unmodified virus-specific primers failed to discern the difference between cDNAs generated from virus specific primers and those generated through false priming. Further, we were unable to accurately measure levels of ONNV (- strand RNA with this assay when higher levels of cDNA generated from the (+ strand were present. Taken together, these results suggest that assays of this type do not accurately quantify levels of the anti-genomic strand present during RNA virus infectious cycles. However, an assay permitting the use of a tag-specific primer was able to distinguish cDNAs transcribed from ONNV (- strand RNA from other cDNAs present, thus allowing accurate quantification of the anti-genomic strand. We also report the sensitivities of two different detection strategies and chemistries, SYBR(R Green and DNA hydrolysis probes, used with our tagged ONNV-specific ssqPCR assays. Finally, we describe development, design and validation of ssqPCR assays for chikungunya virus (CHIKV, the recent cause of large outbreaks of disease in the Indian Ocean

  2. Single-particle cryoEM analysis at near-atomic resolution from several thousand asymmetric subunits.

    Science.gov (United States)

    Passos, Dario Oliveira; Lyumkis, Dmitry

    2015-11-01

    A single-particle cryoEM reconstruction of the large ribosomal subunit from Saccharomyces cerevisiae was obtained from a dataset of ∼75,000 particles. The gold-standard and frequency-limited approaches to single-particle refinement were each independently used to determine orientation parameters for the final reconstruction. Both approaches showed similar resolution curves and nominal resolution values for the 60S dataset, estimated at 2.9 Å. The amount of over-fitting present during frequency-limited refinement was quantitatively analyzed using the high-resolution phase-randomization test, and the results showed no apparent over-fitting. The number of asymmetric subunits required to reach specific resolutions was subsequently analyzed by refining subsets of the data in an ab initio manner. With our data collection and processing strategies, sub-nanometer resolution was obtained with ∼200 asymmetric subunits (or, equivalently for the ribosomal subunit, particles). Resolutions of 5.6 Å, 4.5 Å, and 3.8 Å were reached with ∼1000, ∼1600, and ∼5000 asymmetric subunits, respectively. At these resolutions, one would expect to detect alpha-helical pitch, separation of beta-strands, and separation of Cα atoms, respectively. Using this map, together with strategies for ab initio model building and model refinement, we built a region of the ribosomal protein eL6, which was missing in previous models of the yeast ribosome. The relevance for more routine high-resolution structure determination is discussed.

  3. Heavy ion induced double strand breaks in bacteria and bacteriophages

    Science.gov (United States)

    Micke, U.; Schäfer, M.; Anton, A.; Horneck, G.; Bücker, H.

    DNA damage induced by heavy ions in bacterial cells and bacteriophages such as Bacillus subtilis, E. coli and Bacteriophage Tl were investigated by analyzing the double strand breaks in the chromosomal DNA. This kind of lesion is considered as one of the main reasons for lethal events. To analyze double strand breaks in long molecules of DNA - up to some Mbp in length - the technique of pulse field agarose gel electrophoresis has been used. This allows the detection of one double strand break per genome. Cell lysis and DNA isolation were performed in small agarose blocks directly. This procedure secured minimum DNA destruction by shearing forces. After running a gel, the DNA was stained with ethidium bromide. The light intensity of ethidium bromide fluorescence for both the outcoming (running) DNA and the remaining intact DNA were measured by scanning. The mean number of double strand breaks was calculated by determining the quotient of these intensities. Strand break induction after heavy ion and X-ray irradiation was compared.

  4. The superconducting strand for the CMS solenoid conductor

    CERN Document Server

    Curé, B; Campi, D; Goodrich, L F; Horváth, I L; Kircher, F; Liikamaa, R; Seppälä, J; Smith, R P; Teuho, J; Vieillard, L

    2002-01-01

    The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the LHC project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. Approximately 2000 km of superconducting strand is under procurement for the conductor of the CMS superconducting solenoid. Each strand length is required to be an integral multiple of 2.75 km. The strand is composed of copper- stabilized multifilamentary Nb-Ti with Nb barrier. Individual strands are identified by distinctive patterns of Nb-Ti filaments selected during stacking of the monofilaments. The statistics of piece length, measurements of I/sub c/, n-value, copper RRR, (Cu+Nb)/Nb-Ti ratio, as well as the results of independent cross checks of these quantities, are presented. A study was performed on the CMS strands to investigate the critical current degradation due to various heat treatments. The degradation versus annealing temperature and duration are reported. (4 refs).

  5. Asymmetric liquid wetting and spreading on surfaces with slanted micro-pillar arrays

    KAUST Repository

    Yang, Xiaoming

    2013-01-01

    Uni-directional liquid spreading on asymmetric silicone-fabricated nanostructured surfaces has recently been reported. In this work, uniformly deflected polydimethylsiloxane (PDMS) micro-pillars covered with silver films were fabricated. Asymmetric liquid wetting and spreading behaviors in a preferential direction were observed on the slanted micro-pillar surfaces and a micro-scale thin liquid film advancing ahead of the bulk liquid droplet was clearly observed by high-speed video imaging. It is found that the slanted micro-pillar array is able to promote or inhibit the propagation of this thin liquid film in different directions by the asymmetric capillary force. The spreading behavior of the bulk liquid was guided and finally controlled by this micro-scale liquid film. Different spreading regimes are defined by the relationship between the liquid intrinsic contact angle and the critical angles, which were determined by the pillar height, pillar deflection angle and inter-pillar spacing. © The Royal Society of Chemistry 2013.

  6. Micro-light guides: a new method for measuring tissue fluorescence and reflectance.

    Science.gov (United States)

    Ji, S; Chance, B; Nishiki, K; Smith, T; Rich, T

    1979-03-01

    Three-way light guides containing one or more strands of 25-micron or 80-micron diameter optical fibers in each channel have been constructed and used to measure the NADH fluorescence and UV reflectance from mitochondrial suspensions, the perfused, hemoglobin-free rat liver, and the perfused beating interventricular septum of the rabbit. The optical changes measured with these so-called micro-light guides, which have channels containing one or several strands of optical fibers less than 100 micron, are comparable in magnitude with those measured using much larger conventional light guides. The effect of light scattering on the fluorescence channel has been determined and an empirical equation for correcting the fluorescence channel for light scattering has been obtained for mitochondrial suspensions. A mathematical equation characterizing the optical behavior of a two-way micro-light guide has been derived and has been shown to account satisfactorily for reflectance and fluorescence measurements of a mat surface in air.

  7. Interaction of DAPI with double-stranded ribonucleic acids.

    Science.gov (United States)

    Manzini, G; Xodo, L; Barcellona, M L; Quadrifoglio, F

    1985-01-01

    The interaction of DAPI with natural and synthetic double-stranded polyribonucleotides was studied with different optical and calorimetric methods. The results were similar to those obtained previously with double-stranded polydeoxynucleotides, i.e. two interaction modes, the first of which shows high affinity for AU clusters and consequent strong fluorescence enhancement. The results suggest caution in the use of DAPI as selective fluorescent staining agent for DNA in the presence of RNA. A narrow groove binding model with hydrogen bonds between DAPI and AU pairs is proposed. An intercalation mechanism can be excluded because of the non planarity of DAPI molecule. PMID:4080554

  8. Asymmetric Nano/Microtopography Biases Cytoskeletal Dynamics and Promotes Unidirectional Cell Guidance

    Science.gov (United States)

    Sun, Xiaoyu; Driscoll, Meghan; Guven, Can; Das, Satarupa; Parent, Carole; Fourkas, John; Losert, Wolfgang

    Many biological and physiological processes depend upon directed migration of cells, which is typically mediated by chemical or physical gradients or by signal relay. Here we show that cells can be guided in a single preferred direction based solely on local asymmetries in nano/microtopography on subcellular scales. These asymmetries can be repeated, and thereby provide directional guidance, over arbitrarily large areas. The direction and strength of the guidance is sensitive to the details of the nano/microtopography, suggesting that this phenomenon plays a context-dependent role in vivo. We demonstrate that asymmetric nano/microtopography guides the direction of internal actin polymerization waves (esotaxis), and that cells move in the same direction as these waves (microthigmotaxis). This phenomenon is observed both for the pseudopod-dominated migration of the amoeboid Dictyostelium discoideum and for the lamellipod-driven migration of human neutrophils. The conservation of this mechanism across cell types and the asymmetric shape of many natural scaffolds suggests that actin-wave-based guidance is important in biology and physiology.

  9. Asymmetric-Structure Analysis of Carbon and Energy Markets

    Science.gov (United States)

    Xu, Wei; Cao, Guangxi

    2016-02-01

    This study aimed to investigate the asymmetric structure between the carbon and energy markets from two aspects of different trends (up or down) and volatility-transmission direction using asymmetric detrended cross-correlation analysis (DCCA) cross-correlation coefficient test, multifractal asymmetric DCCA (MF-ADCCA) method, asymmetric volatility-constrained correlation metric and time rate of information-flow approach. We sampled 1283 observations from January 2008 to December 2012 among pairs of carbon and energy markets for analysis. Empirical results show that the (1) asymmetric characteristic from the cross-correlation between carbon and returns in the energy markets is significant, (2) asymmetric cross-correlation between carbon and energy market price returns is persistent and multifractral and (3) volatility of the base assets of energy market returns is more influential to the base asset of the carbon market than that of the energy market.

  10. [Effect of single-stranded and double-stranded breaks on the melting temperature of phage T2 DNA].

    Science.gov (United States)

    Iurgaĭtis, A P; Lazurkin, Iu S; Bannikov, Iu A

    1979-01-01

    The effect of single- and double-stranded breaks in DNA phage T2, on the melting temperature of this DNA in the 0,05 M SSC solution, was investigated. The number of cleavages per 1000 nucleotide pairs varied in the range of 0 to 10. It is shown that single- and double-stranded breaks affect the melting temperature with approximately (within 20%) the same efficiency. The relationship between the melting temperature shift (delta Tm) and the number of cleavages is non-linear. The magnitude of the effect is characterized by delta Tm of 2 +/- 0.4 degrees C for the average inter-cleavage distance of 200 base pairs. It is shown that the observed melting curves are non-equilibrium ones, which is probably due to the fact that the effect of cleavages on the melting temperature is largely results from the complete and practically irreversible separation of strands.

  11. Quantum optics of lossy asymmetric beam splitters

    Science.gov (United States)

    Uppu, Ravitej; Wolterink, Tom A. W.; Tentrup, Tristan B. H.; Pinkse, Pepijn W. H.

    2016-07-01

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2$\\times$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 matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers.

  12. Improved DFIG Capability during Asymmetrical Grid Faults

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede

    2015-01-01

    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....

  13. Resonance phenomena for asymmetric weakly nonlinear oscillator

    Institute of Scientific and Technical Information of China (English)

    钱定边

    2002-01-01

    We establish the coexistence of periodic solution and unbounded solution, the infinity of largeamplitude subharmonics for asymmetric weakly nonlinear oscillator x" + a2x+ - b2x- + h(x) = p(t) with h(±∞) - 0 and xh(x) → +∞(x →∞), assuming that M(τ ) has zeros which are all simple and M(τ ) 0respectively, where M(τ ) is a function related to the piecewise linear equation x" + a2x+ - b2x- = p(t).``

  14. Dynamic Conditional Correlations for Asymmetric Processes

    OpenAIRE

    Asai, Manabu; McAleer, Michael

    2011-01-01

    The paper develops two Dynamic Conditional Correlation (DCC) models, namely the Wishart DCC (wDCC) model. The paper applies the wDCC approach to the exponential GARCH (EGARCH) and GJR models to propose asymmetric DCC models. We use the standardized multivariate t-distribution to accommodate heavy-tailed errors. The paper presents an empirical example using the trivariate data of the Nikkei 225, Hang Seng and Straits Times Indices for estimating and forecasting the wDCC-EGARCH and wDCC-GJR mod...

  15. On asymmetric causal relationships in Petropolitics

    Directory of Open Access Journals (Sweden)

    Balan Feyza

    2016-01-01

    Full Text Available The aim of this paper is to examine whether the First Law of Petropolitics denominated by Friedman in 2006 is valid for OPEC countries. To do this, this paper analyses the relationship between political risk and oil supply by applying the asymmetric panel causality test suggested by Hatemi-J (2011 to these countries for the period 1984-2014. The results show that the First Law of Petropolitics is valid for Angola, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, and the UAE, given that positive oil supply shocks significantly lead to negative political stability shocks, and negative oil supply shocks significantly lead to positive shocks in political stability.

  16. Quantum optics of lossy asymmetric beam splitters

    CERN Document Server

    Uppu, Ravitej; Tentrup, Tristan B H; Pinkse, Pepijn W H

    2016-01-01

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2$\\times$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 matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers.

  17. Asymmetric chemical reactions by polarized quantum beams

    Science.gov (United States)

    Takahashi, Jun-Ichi; Kobayashi, Kensei

    One of the most attractive hypothesis for the origin of homochirality in terrestrial bio-organic compounds (L-amino acid and D-sugar dominant) is nominated as "Cosmic Scenario"; a chiral impulse from asymmetric excitation sources in space triggered asymmetric reactions on the surfaces of such space materials as meteorites or interstellar dusts prior to the existence of terrestrial life. 1) Effective asymmetric excitation sources in space are proposed as polarized quantum beams, such as circularly polarized light and spin polarized electrons. Circularly polarized light is emitted as synchrotron radiation from tightly captured electrons by intense magnetic field around neutron stars. In this case, either left-or right-handed polarized light can be observed depending on the direction of observation. On the other hand, spin polarized electrons is emitted as beta-ray in beta decay from radioactive nuclei or neutron fireballs in supernova explosion. 2) The spin of beta-ray electrons is longitudinally polarized due to parity non-conservation in the weak interaction. The helicity (the the projection of the spin onto the direction of kinetic momentum) of beta-ray electrons is universally negative (left-handed). For the purpose of verifying the asymmetric structure emergence in bio-organic compounds by polarized quantum beams, we are now carrying out laboratory simulations using circularly polarized light from synchrotron radiation facility or spin polarized electron beam from beta-ray radiation source. 3,4) The target samples are solid film or aqueous solution of racemic amino acids. 1) K.Kobayashi, K.Kaneko, J.Takahashi, Y.Takano, in Astrobiology: from simple molecules to primitive life; Ed. V.Basiuk; American Scientific Publisher: Valencia, 2008. 2) G.A.Gusev, T.Saito, V.A.Tsarev, A.V.Uryson, Origins Life Evol. Biosphere. 37, 259 (2007). 3) J.Takahashi, H.Shinojima, M.Seyama, Y.Ueno, T.Kaneko, K.Kobayashi, H.Mita, M.Adachi, M.Hosaka, M.Katoh, Int. J. Mol. Sci. 10, 3044

  18. RHIC operation with asymmetric collisions in 2015

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Aschenauer, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Atoian, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Connolly, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ottavio, T. D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Drees, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gardner, C. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hayes, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Laster, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Makdisi, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marr, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Montag, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Morris, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Narayan, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nayak, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nemesure, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pile, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Poblaguev, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roser, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schmidke, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Severino, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Shrey, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Smith, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Steski, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tepikian, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); White, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yip, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zaltsman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zeno, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhang, S. Y. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-08-07

    To study low-x shadowing/saturation physics as well as other nuclear effects [1], [2], proton-gold (p-Au, for 5 weeks) and proton-Aluminum (p-Al, for 2 weeks) collisions were provided for experiments in 2015 at the Relativistic Heavy Ion Collider (RHIC), with polarized proton beam in the Blue ring and Au/Al beam in the Yellow ring. The special features of the asymmetric run in 2015 will be introduced. The operation experience will be reviewed as well in the report.

  19. Photoresponse of silicon with asymmetric area contacts

    Science.gov (United States)

    Rabbani, M. Golam; Sundararajan, Jency P.; Verma, Amit; Nekovei, Reza; Khader, Mahmoud M.; Darling, R. B.; Patil, Sunil R.

    2017-01-01

    We report on high performance metal-semiconductor-metal (MSM) photosensors based on asymmetric metal pad areas. The reported devices require a single-step metal deposition, and exhibit large photo response even under zero-bias. Moreover the devices offer fast and stable light switching behavior. Device fabrication and electrical characterization results are presented that are further analyzed with TCAD modeling and simulation. Device simulations show that contact asymmetry along with surface recombination and barrier lowering plays an important role in the MSM I-V characteristics.

  20. Chiral Diamine-catalyzed Asymmetric Aldol Reaction

    Institute of Scientific and Technical Information of China (English)

    LI Hui; XU Da-zhen; WU Lu-lu; WANG Yong-mei

    2012-01-01

    A highly efficient catalytic system composed of a simple and commercially available chiral primary diamine (1R,2R)-cyclohexane-1,2-diamine(6) and trifluoroacetic acid(TFA) was employed for asymmetric Aldol reaction in i-PrOH at room temperature.A loading of 10%(molar fraction) catalyst 6 with TFA as a cocatalyst could catalyze the Aldol reactions of various ketones or aldehydes with a series of aromatic aldehydes,furnishing Aldol products in moderate to high yields(up to >99%) with enantioselectivities of up to >99% and diastereoselectivities of up to 99:1.

  1. Analysis of Asymmetric Piezoelectric Composite Beam

    CERN Document Server

    Chen, J -S; Wu, K -C

    2008-01-01

    This paper deals with the vibration analysis of an asymmetric composite beam composed of glass a piezoelectric material. The Bernoulli's beam theory is adopted for mechanical deformations, and the electric potential field of the piezoelectric material is assumed such that the divergence-free requirement of the electrical displacements is satisfied. The accuracy of the analytic model is assessed by comparing the resonance frequencies obtained by the analytic model with those obtained by the finite element method. The model developed can be used as a tool for designing piezoelectric actuators such as micro-pumps.

  2. Asymmetric Synthesis of Both Enantiomers of Disparlure

    Institute of Scientific and Technical Information of China (English)

    王志刚; 郑剑峰; 黄培强

    2012-01-01

    Starting from propargyl alcohol (12), and on the basis of Zhou's modified Sharpless asymmetric epoxidation, the sex pheromone of the Gypsy moth, disparlure (+)-8 and its enantiomer (-)-8 have been synthesized, each in six steps, with overall yields of 29% for (+)-8 and 27% for (-)-8 (ee〉98%). The use of the sequential coupling tactic renders the method flexible, which is applicable to the synthesis of other cis-epoxy pheromones.

  3. Nanotribology of Symmetric and Asymmetric Liquid Lubricants

    Directory of Open Access Journals (Sweden)

    Shinji Yamada

    2010-03-01

    Full Text Available When liquid molecules are confined in a narrow gap between smooth surfaces, their dynamic properties are completely different from those of the bulk. The molecular motions are highly restricted and the system exhibits solid-like responses when sheared slowly. This solidification behavior is very dependent on the molecular geometry (shape of liquids because the solidification is induced by the packing of molecules into ordered structures in confinement. This paper reviews the measurements of confined structures and friction of symmetric and asymmetric liquid lubricants using the surface forces apparatus. The results show subtle and complex friction mechanisms at the molecular scale.

  4. Neuronal Alignment On Asymmetric Textured Surfaces

    CERN Document Server

    Beighley, Ross; Sekeroglu, Koray; Atherton, Timothy; Demirel, Melik C; Staii, Cristian

    2013-01-01

    Axonal growth and the formation of synaptic connections are key steps in the development of the nervous system. Here we present experimental and theoretical results on axonal growth and interconnectivity in order to elucidate some of the basic rules that neuronal cells use for functional connections with one another. We demonstrate that a unidirectional nanotextured surface can bias axonal growth. We perform a systematic investigation of neuronal processes on asymmetric surfaces and quantify the role that biomechanical surface cues play in neuronal growth. These results represent an important step towards engineering directed axonal growth for neuro-regeneration studies.

  5. Asymmetric acoustic transmission in graded beam

    Science.gov (United States)

    Jing, Li; Wu, Jiu Hui; Guan, Dong; Lu, Kuan; Gao, Nansha; Songhua, Cao

    2016-12-01

    We demonstrate the dynamic effective material parameters and vibration performance of a graded beam. The structure of the beam was composed of several unit cells with different fill factors. The dispersion relations and energy band structures of each unit cell were calculated using the finite element method (FEM). The dynamic effective material parameters in each unit cell of the graded beam were determined by the dispersion relations and energy band structures. Longitudinal wave propagation was investigated using a numerical method and FEM. The results show that the graded beam allows asymmetric acoustic transmission over a wide range of frequencies.

  6. An Asymmetric Block Dynamic Conditional Correlation Multivariate GARCH Model

    OpenAIRE

    Vargas, Gregorio A.

    2006-01-01

    The Block DCC model for determining dynamic correlations within and between groups of financial asset returns is extended to account for asymmetric effects. Simulation results show that the Asymmetric Block DCC model is competitive in in-sample forecasting and performs better than alternative DCC models in out-of-sample forecasting of conditional correlation in the presence of asymmetric effect between blocks of asset returns. Empirical results demonstrate that the model is able to capture ...

  7. Asymmetric joint multifractal analysis in Chinese stock markets

    Science.gov (United States)

    Chen, Yuwen; Zheng, Tingting

    2017-04-01

    In this paper, the asymmetric joint multifractal analysis method based on statistical physics is proposed to explore the asymmetric correlation between daily returns and trading volumes in Chinese stock markets. The result shows asymmetric multifractal correlations exist between return and trading volume in Chinese stock markets. Moreover, when the stock indexes are upward, the fluctuations of returns are always weaker than when they are downward, whether the trading volumes are more or less.

  8. Asymmetric Campaigning as a Rational Choice: Planning Considerations

    Science.gov (United States)

    2006-06-01

    Maslow identified five levels: survival, safety, belonging, esteem, and self-actualization. He presented his theory as a pyramid with five layers...to be sustained by actions of the asymmetric opponent. For the media-fed frenzy over constraints and protraction to continue, the asymmetric...lot of people. The reason for this is twofold. First, the actor needs sufficient support to exist and to sustain an asymmetric campaign. Second, the

  9. Linear-After-The-Exponential (LATE)-PCR: Primer design criteria for high yields of specific single-stranded DNA and improved real-time detection

    Science.gov (United States)

    Pierce, Kenneth E.; Sanchez, J. Aquiles; Rice, John E.; Wangh, Lawrence J.

    2005-01-01

    Traditional asymmetric PCR uses conventional PCR primers at unequal concentrations to generate single-stranded DNA. This method, however, is difficult to optimize, often inefficient, and tends to promote nonspecific amplification. An alternative approach, Linear-After-The-Exponential (LATE)-PCR, solves these problems by using primer pairs deliberately designed for use at unequal concentrations. The present report systematically examines the primer design parameters that affect the exponential and linear phases of LATE-PCR amplification. In particular, we investigated how altering the concentration-adjusted melting temperature (Tm) of the limiting primer (TmL) relative to that of the excess primer (TmX) affects both amplification efficiency and specificity during the exponential phase of LATE-PCR. The highest reaction efficiency and specificity were observed when TmL - TmX ≥ 5°C. We also investigated how altering TmX relative to the higher Tm of the double-stranded amplicon (TmA) affects the rate and extent of linear amplification. Excess primers with TmX closer to TmA yielded higher rates of linear amplification and stronger signals from a hybridization probe. These design criteria maximize the yield of specific single-stranded DNA products and make LATE-PCR more robust and easier to implement. The conclusions were validated by using primer pairs that amplify sequences within the cystic fibrosis transmembrane regulator (CFTR) gene, mutations of which are responsible for cystic fibrosis. PMID:15937116

  10. Ligation of double-stranded and single-stranded [Oligo(dT)] DNA by vaccinia virus DNA ligase

    OpenAIRE

    1996-01-01

    Vaccinia virus DNA ligase has been expressed in Escherichia coli, purified, and biochemically characterized. The enzyme ligates double-stranded (ds) DNA substrates with either cohesive or blunt-end termini and the latter reaction is stimulated by PEG. Vaccinia virus DNA ligase can also ligate oligo(dT) when annealed to either a poly(dA) or a poly(rA) backbone and, remarkably, free oligo(dT). This ligation of a single-stranded (ss) substrate is unique among eukaryotic DNA ligases. The enzyme r...

  11. Asymmetric transmission: a generic property of lossy periodic interfaces

    CERN Document Server

    Plum, E; Zheludev, N I

    2010-01-01

    Asymmetric transmission of circularly polarized waves is a well-established property of lossy, anisotropic, two-dimensionally chiral patterns. Here we show that asymmetric transmission can be observed for oblique incidence onto any lossy periodically structured plane. Our results greatly expand the range of natural and artificial materials in which directionally asymmetric transmission can be expected making it a cornerstone electromagnetic effect rather than a curiosity of planar chiral metamaterials. Prime candidates for asymmetric transmission at oblique incidence are rectangular arrays of plasmonic spheres or semiconductor quantum dots, lossy double-periodic gratings and planar metamaterial structures.

  12. Quantity Discount Scheme in Supply Chain under Asymmetric Information

    Institute of Scientific and Technical Information of China (English)

    LI Ji-bin; PENG Zuo-he

    2007-01-01

    Quantity discount scheme plays an important role in supply chain management. The different quantity discount schemes under symmetric (full) information and asymmetric information, are analyzed by using principal-agent and optimal control theory. As a result, the research reveals that the optimal quantity discount solution under symmetric information is a special case of that under asymmetric information. At the same price, the critical value of quantity discount under asymmetric information is much lower than that under asymmetric information. Therefore, this leads to less cost for retailers and smaller profit for their supplier.

  13. Single strand annealing and ATP-independent strand exchange activities of yeast and human DNA2: possible role in Okazaki fragment maturation.

    Science.gov (United States)

    Masuda-Sasa, Taro; Polaczek, Piotr; Campbell, Judith L

    2006-12-15

    The Dna2 protein is a multifunctional enzyme with 5'-3' DNA helicase, DNA-dependent ATPase, 3' exo/endonuclease, and 5' exo/endonuclease. The enzyme is highly specific for structures containing single-stranded flaps adjacent to duplex regions. We report here two novel activities of both the yeast and human Dna2 helicase/nuclease protein: single strand annealing and ATP-independent strand exchange on short duplexes. These activities are independent of ATPase/helicase and nuclease activities in that mutations eliminating either nuclease or ATPase/helicase do not inhibit strand annealing or strand exchange. ATP inhibits strand exchange. A model rationalizing the multiple catalytic functions of Dna2 and leading to its coordination with other enzymes in processing single-stranded flaps during DNA replication and repair is presented.

  14. Polarity, Continuity, and Alignment in Plant Vascular Strands

    Institute of Scientific and Technical Information of China (English)

    Megan G. Sawchuk; Enrico Scarpella

    2013-01-01

    Plant vascular cells are joined end to end along uninterrupted lines to connect shoot organs with roots;vascular strands are thus polar, continuous, and internally aligned. What controls the formation of vascular strands with these properties? The “auxin canalization hypothesis”-based on positive feedback between auxin flow through a cell and the cell’s capacity for auxin transport-predicts the selection of continuous files of cells that transport auxin polarly, thus accounting for the polarity and continuity of vascular strands. By contrast, polar, continuous auxin transport-though required-is insufficient to promote internal alignment of vascular strands, implicating additional factors. The auxin canalization hypothesis was derived from the response of mature tissue to auxin application but is consistent with molecular and cellular events in embryo axis formation and shoot organ development. Objections to the hypothesis have been raised based on vascular organizations in callus tissue and shoot organs but seem unsupported by available evidence. Other objections call instead for further research; yet the inductive and orienting influence of auxin on continuous vascular differentiation remains unique.

  15. DNA strand exchange catalyzed by molecular crowding in PEG solutions

    KAUST Repository

    Feng, Bobo

    2010-01-01

    DNA strand exchange is catalyzed by molecular crowding and hydrophobic interactions in concentrated aqueous solutions of polyethylene glycol, a discovery of relevance for understanding the function of recombination enzymes and with potential applications to DNA nanotechnology. © 2010 The Royal Society of Chemistry.

  16. Nucleic Acid Analogue Induced Transcription of Double Stranded DNA

    DEFF Research Database (Denmark)

    1998-01-01

    RNA is transcribed from a double stranded DNA template by forming a complex by hybridizing to the template at a desired transcription initiation site one or more oligonucleic acid analogues of the PNA type capable of forming a transcription initiation site with the DNA and exposing the complex...

  17. Negative-strand RNA viruses: The plant-infecting counterparts

    NARCIS (Netherlands)

    Kormelink, R.J.M.; Garcia, M.L.; Goodin, M.; Sasaya, T.; Haenni, A.L.

    2011-01-01

    While a large number of negative-strand (-)RNA viruses infect animals and humans, a relative small number have plants as their primary host. Some of these have been classified within families together with animal/human infecting viruses due to similarities in particle morphology and genome organizat

  18. Chromatin remodelers in the DNA double strand break response

    NARCIS (Netherlands)

    Smeenk, Godelieve

    2012-01-01

    During my PhD project, I studied the role of several chromatin remodelers in the DNA double strand break (DSB) response. We discovered that both CHD4 and SMARCA5 are required for ubiquitin signaling through the E3 ubiquitin ligases RNF8 and RNF168, which is a central signaling event in the response

  19. On the Distinction between Preposition Stranding and Orphan Prepositions

    Science.gov (United States)

    Roberge, Yves

    2012-01-01

    Poplack, Zentz and Dion (PZD; Poplack, Zentz & Dion, 2011, this issue) examine the often unquestioned assumption that the existence of preposition stranding (PS) in Canadian French is linked to the presence of a contact situation with English in the North American context. Although this issue has been the topic of previous research from a…

  20. Cetaceans stranded in the Netherlands from 1998 to 2007

    NARCIS (Netherlands)

    Camphuysen, C.J.; Smeenk, C.; Addink, M.; Jansen, O.E.

    2008-01-01

    Between 1998 and 2007, 2063 cetaceans were found stranded in the Netherlands, representing at least 14 species. Two species, humpback whale (Megaptera novaeangliae) and Blainville’s beaked whale (Mesoplodon densirostris), are additions to the Dutch list. Apart from the first humpback whales, relativ

  1. Cetaceans stranded in the Netherlands from 1998 to 2007

    NARCIS (Netherlands)

    Camphuysen, C.J.; Smeenk, C.; Addink, M.; Grouw, van H.; Jansen, O.E.

    2008-01-01

    Between 1998 and 2007, 2063 cetaceans were found stranded in the Netherlands, representing at least 14 species. Two species, humpback whale (Megaptera novaeangliae) and Blainville's beaked whale (Mesoplodon densirostris), are additions to the Dutch list. Apart from the first humpback whales, relativ

  2. Targeting DNA double-strand breaks with TAL effector nucleases.

    Science.gov (United States)

    Christian, Michelle; Cermak, Tomas; Doyle, Erin L; Schmidt, Clarice; Zhang, Feng; Hummel, Aaron; Bogdanove, Adam J; Voytas, Daniel F

    2010-10-01

    Engineered nucleases that cleave specific DNA sequences in vivo are valuable reagents for targeted mutagenesis. Here we report a new class of sequence-specific nucleases created by fusing transcription activator-like effectors (TALEs) to the catalytic domain of the FokI endonuclease. Both native and custom TALE-nuclease fusions direct DNA double-strand breaks to specific, targeted sites.

  3. Sensitive, Specific Complementary - Strand Optical Detection of Viral RNA

    Science.gov (United States)

    1997-06-01

    promise Its components have been characterized and proven to show unparalleled sensitivity; in addition, an innovative method for improving...sensing. 14. SUBJECT TERMS 15. NUMBER OF PAGES RNA, enterovirii, biosensor, evanscent waves, refractometry , 31 phase detection, complementary strand...Phase Measurements (10) Tri-Phase Detection Method . (11) Phase Detectors (12) Phase Processor Board (13) Laboratory Experim ents

  4. Double strand break repair functions of histone H2AX

    Energy Technology Data Exchange (ETDEWEB)

    Scully, Ralph, E-mail: rscully@bidmc.harvard.edu; Xie, Anyong

    2013-10-15

    Chromosomal double strand breaks provoke an extensive reaction in neighboring chromatin, characterized by phosphorylation of histone H2AX on serine 139 of its C-terminal tail (to form “γH2AX”). The γH2AX response contributes to the repair of double strand breaks encountered in a variety of different contexts, including those induced by ionizing radiation, physiologically programmed breaks that characterize normal immune cell development and the pathological exposure of DNA ends triggered by telomere dysfunction. γH2AX also participates in the evolutionarily conserved process of sister chromatid recombination, a homologous recombination pathway involved in the suppression of genomic instability during DNA replication and directly implicated in tumor suppression. At a biochemical level, the γH2AX response provides a compelling example of how the “histone code” is adapted to the regulation of double strand break repair. Here, we review progress in research aimed at understanding how γH2AX contributes to double strand break repair in mammalian cells.

  5. Asymmetric disassembly and robustness in declining networks.

    Science.gov (United States)

    Saavedra, Serguei; Reed-Tsochas, Felix; Uzzi, Brian

    2008-10-28

    Mechanisms that enable declining networks to avert structural collapse and performance degradation are not well understood. This knowledge gap reflects a shortage of data on declining networks and an emphasis on models of network growth. Analyzing >700,000 transactions between firms in the New York garment industry over 19 years, we tracked this network's decline and measured how its topology and global performance evolved. We find that favoring asymmetric (disassortative) links is key to preserving the topology and functionality of the declining network. Based on our findings, we tested a model of network decline that combines an asymmetric disassembly process for contraction with a preferential attachment process for regrowth. Our simulation results indicate that the model can explain robustness under decline even if the total population of nodes contracts by more than an order of magnitude, in line with our observations for the empirical network. These findings suggest that disassembly mechanisms are not simply assembly mechanisms in reverse and that our model is relevant to understanding the process of decline and collapse in a broad range of biological, technological, and financial networks.

  6. Algebraic Davis Decomposition and Asymmetric Doob Inequalities

    Science.gov (United States)

    Hong, Guixiang; Junge, Marius; Parcet, Javier

    2016-09-01

    In this paper we investigate asymmetric forms of Doob maximal inequality. The asymmetry is imposed by noncommutativity. Let {({M}, τ)} be a noncommutative probability space equipped with a filtration of von Neumann subalgebras {({M}_n)_{n ≥ 1}}, whose union {bigcup_{n≥1}{M}_n} is weak-* dense in {{M}}. Let {{E}_n} denote the corresponding family of conditional expectations. As an illustration for an asymmetric result, we prove that for {1 spaces {{H}_p^r({M})} and {{H}_p^c({M})} respectively. In particular, this solves a problem posed by the Defant and Junge in 2004. In the case p = 1, our results establish a noncommutative form of the Davis celebrated theorem on the relation betwe en martingale maximal and square functions in L 1, whose noncommutative form has remained open for quite some time. Given {1 ≤ p ≤ 2}, we also provide new weak type maximal estimates, which imply in turn left/right almost uniform convergence of {{E}_n(x)} in row/column Hardy spaces. This improves the bilateral convergence known so far. Our approach is based on new forms of Davis martingale decomposition which are of independent interest, and an algebraic atomic description for the involved Hardy spaces. The latter results are new even for commutative von Neumann algebras.

  7. Asymmetric DSL Technology of Signal Transmission

    Directory of Open Access Journals (Sweden)

    Dražen Kovačević

    2005-05-01

    Full Text Available Asymmetric flow of information is the key feature of theADSL (Asymmetric Digital Subscriber Loop technology, i.e.higher data transmission rate towards the user than from theuser towards the network. Characteristic is the short messagesending by the user with a certain request to the se!Ver. These!Ver responds to the request by a significantly longer messageof various electronic forms (data, digitized speech, pictures orvideo. Therefore, this technology is most often used by smalland medium users. ADSL is currently the only commerciallyavailable DSL technology which is still experiencing the breakthroughon the seiVice market. It enables faster access to theInternet, LAN (Local Area Network, videoconferencing, VoD(Video on Demand and interactive multimedia. In order tostandardize such se/Vices, the !TU (International TelecommunicationsUnion G. 992.1 (standardized DMT-discrete multi-tone line coding technology and ANSJ (American NationalStandards Institution Tl.413-95!98 are used for ADSL. DMT(Discrete Multi Tone, as the more popular one, uses the linecoding technique, which splits a certain frequency range intoseveral sub-channels. Most of these sub-channels are used forupstream and downstream transmission of speech and data,whereas some are used as pilot signals or kept in rese/Ve. Suchmodulation technique expands the frequency spectrum, allowingthe usage ofbroadband se/Vices per one pair of wires. In thisway the sharing of speech and data se/Vice transmission is realized.

  8. An asymmetric B factory based on PEP

    Energy Technology Data Exchange (ETDEWEB)

    1991-02-01

    In this report we describe a design for a high-luminosity Asymmetric B Factory to be built in the PEP tunnel on the SLAC site. This proposal, a collaborative effort SLAC, LBL, and LLNL, is the culmination of more than two years of effort aimed at the design and construction of an asymmetric e{sup +}e{sup {minus}} collider capable of achieving a luminosity of L = 3 {times} 10{sup 33} cm{sup {minus}2} s{sup {minus}1}. The configuration adopted utilizes two storage rings, and electron ring operating at 9 GeV and a positron ring at 3.1 GeV, each with a circumference of 2200 m. The high-energy ring is an upgrade of the PEP storage ring at SLAC; all PEP magnets and most power supplies will be reused. The upgrade consists primarily of replacing the PEP vacuum chamber and RF system with newly designed versions optimized for the high-current environment of the B Factory. The low-energy ring will be newly constructed and will be situated atop the high-energy ring in the PEP tunnel. Utilities already installed in the PEP tunnel are largely sufficient to operate the two B Factory storage rings.

  9. Evolutionary stability in the asymmetric volunteer's dilemma.

    Directory of Open Access Journals (Sweden)

    Jun-Zhou He

    Full Text Available It is often assumed that in public goods games, contributors are either strong or weak players and each individual has an equal probability of exhibiting cooperation. It is difficult to explain why the public good is produced by strong individuals in some cooperation systems, and by weak individuals in others. Viewing the asymmetric volunteer's dilemma game as an evolutionary game, we find that whether the strong or the weak players produce the public good depends on the initial condition (i.e., phenotype or initial strategy of individuals. These different evolutionarily stable strategies (ESS associated with different initial conditions, can be interpreted as the production modes of public goods of different cooperation systems. A further analysis revealed that the strong player adopts a pure strategy but mixed strategies for the weak players to produce the public good, and that the probability of volunteering by weak players decreases with increasing group size or decreasing cost-benefit ratio. Our model shows that the defection probability of a "strong" player is greater than the "weak" players in the model of Diekmann (1993. This contradicts Selten's (1980 model that public goods can only be produced by a strong player, is not an evolutionarily stable strategy, and will therefore disappear over evolutionary time. Our public good model with ESS has thus extended previous interpretations that the public good can only be produced by strong players in an asymmetric game.

  10. At Low SNR Asymmetric Quantizers Are Better

    CERN Document Server

    Koch, Tobias

    2012-01-01

    We study the capacity of the discrete-time Gaussian channel when its output is quantized with a one-bit quantizer. We focus on the low signal-to-noise ratio (SNR) regime, where communication at very low spectral efficiencies takes place. In this regime a symmetric threshold quantizer is known to reduce channel capacity by 2/pi, i.e., to cause an asymptotic power loss of approximately two decibels. Here it is shown that this power loss can be entirely avoided by using asymmetric threshold quantizers and asymmetric signaling constellations. We prove that in order to avoid this power loss flash-signaling input-distributions are essential. Consequently, one-bit output quantization of the Gaussian channel reduces spectral efficiency. Threshold quantizers are not only asymptotically optimal: as we prove, at every fixed SNR, a threshold quantizer maximizes capacity among all one-bit output quantizers. The picture changes on the Rayleigh-fading channel. In the noncoherent case we show that a one-bit output quantizer ...

  11. Instability of asymmetric continuous shaft system

    Science.gov (United States)

    Srinath, R.; Sarkar, Abhijit; Sekhar, A. S.

    2016-11-01

    In this work, the governing equation of asymmetric continuous shaft in inertial frame of reference is studied. In particular, determination of the parameter ranges for the stability or instability of the shaft response is the focus of the present work. The governing equations are a fourth-order coupled partial differential equations containing time dependent coefficients. The equations are non-dimensionalized in terms of two parameters related to the average moment of inertia and the difference of moments of inertia about the principal axes. Using the latter as the asymptotic parameter and employing modal superposition, a formal methodology based on perturbation methods is developed to ascertain the stability and instability characteristics. The methodology is applicable to shafts subjected to some of the classical boundary conditions viz. simply supported, cantilever, and fixed-fixed. Similar stability curves are obtained for each mode for these different boundary conditions. The novel non-dimensionalization scheme chosen leads to the stability boundaries as well as the loci of varying speeds to be in the form of straight lines. The intersection of these lines determine the stable and unstable speed ranges of different asymmetric shafts. The results are generalized for different material and geometric properties of the shaft.

  12. Asymmetric transition disks: Vorticity or eccentricity?

    CERN Document Server

    Zsom, A; Ghanbari, J

    2013-01-01

    Context. Transition disks typically appear in resolved millimeter observations as giant dust rings surrounding their young host stars. More accurate observations with ALMA have shown several of these rings to be in fact asymmetric: they have lopsided shapes. It has been speculated that these rings act as dust traps, which would make them important laboratories for studying planet formation. It has been shown that an elongated giant vortex produced in a disk with a strong viscosity jump strikingly resembles the observed asymmetric rings. Aims. We aim to study a similar behavior for a disk in which a giant planet is embedded. However, a giant planet can induce two kinds of asymmetries: (1) a giant vortex, and (2) an eccentric disk. We studied under which conditions each of these can appear, and how one can observationally distinguish between them. This is important because only a vortex can trap particles both radially and azimuthally, while the eccentric ring can only trap particles in radial direction. Method...

  13. Properties of asymmetrically evolved community networks

    Institute of Scientific and Technical Information of China (English)

    Cui Di; Gao Zi-You; Zheng Jian-Feng

    2009-01-01

    This paper studies a simple asymmetrically evolved community network with a combination of preferential at-tachment and random properties. An important issue about community networks is to discover the different utility increments of two nodes, where the utility is introduced to investigate the asymmetrical effect of connecting two nodes. On the other hand, the connection of two nodes in community networks can be classified as two nodes belonging to the same or to different communities. The simulation results show that the model can reproduce a power-law utility distribution P(u)~ u-σ,σ=2+ 1/p, which can be obtained by using mean-field approximation methods. Furthermore, the model exhibits exponential behaviour with respect to small values of a parameter denoting the random effect in our model at the low-utility region and a power-law feature with respect to big values of this parameter at the high-utility region, which is in good agreement with theoretical analysis. This kind of community network can reproduce a unique utility distribution by theoretical and numerical analysis.

  14. Survey of Reflection-Asymmetric Nuclear Deformations

    Science.gov (United States)

    Olsen, Erik; Cao, Yuchen; Nazarewicz, Witold; Schunck, Nicolas

    2016-09-01

    Due to spontaneous symmetry breaking it is possible for a nucleus to have a deformed shape in its ground state. It is theorized that atoms whose nuclei have reflection-asymmetric or pear-like deformations could have non-zero electric dipole moments (EDMs). Such a trait would be evidence of CP-violation, a feature that goes beyond the Standard Model of Physics. It is the purpose of this project to predict which nuclei exhibit a reflection-asymmetric deformation and which of those would be the best candidates for an EDM measuring experiment. Using nuclear Density Functional Theory along with the new computer code AxialHFB and massively parallel computing we calculated ground state nuclear properties for thousands of even-even nuclei across the nuclear chart: from light to superheavy and from stable to short-lived systems. Six different Energy Density Functionals (EDFs) were used to assess systematic errors in our calculations. These results are to be added to the website Massexplorer (http://massexplorer.frib.msu.edu/) which contains results from earlier mass table calculations and information on single quasiparticle energies.

  15. RNA STRAND: The RNA Secondary Structure and Statistical Analysis Database

    Directory of Open Access Journals (Sweden)

    Andronescu Mirela

    2008-08-01

    Full Text Available Abstract Background The ability to access, search and analyse secondary structures of a large set of known RNA molecules is very important for deriving improved RNA energy models, for evaluating computational predictions of RNA secondary structures and for a better understanding of RNA folding. Currently there is no database that can easily provide these capabilities for almost all RNA molecules with known secondary structures. Results In this paper we describe RNA STRAND – the RNA secondary STRucture and statistical ANalysis Database, a curated database containing known secondary structures of any type and organism. Our new database provides a wide collection of known RNA secondary structures drawn from public databases, searchable and downloadable in a common format. Comprehensive statistical information on the secondary structures in our database is provided using the RNA Secondary Structure Analyser, a new tool we have developed to analyse RNA secondary structures. The information thus obtained is valuable for understanding to which extent and with which probability certain structural motifs can appear. We outline several ways in which the data provided in RNA STRAND can facilitate research on RNA structure, including the improvement of RNA energy models and evaluation of secondary structure prediction programs. In order to keep up-to-date with new RNA secondary structure experiments, we offer the necessary tools to add solved RNA secondary structures to our database and invite researchers to contribute to RNA STRAND. Conclusion RNA STRAND is a carefully assembled database of trusted RNA secondary structures, with easy on-line tools for searching, analyzing and downloading user selected entries, and is publicly available at http://www.rnasoft.ca/strand.

  16. Excited states in DNA strands investigated by ultrafast laser spectroscopy.

    Science.gov (United States)

    Chen, Jinquan; Zhang, Yuyuan; Kohler, Bern

    2015-01-01

    Ultrafast laser experiments on carefully selected DNA model compounds probe the effects of base stacking, base pairing, and structural disorder on excited electronic states formed by UV absorption in single and double DNA strands. Direct π-orbital overlap between two stacked bases in a dinucleotide or in a longer single strand creates new excited states that decay orders of magnitude more slowly than the generally subpicosecond excited states of monomeric bases. Half or more of all excited states in single strands decay in this manner. Ultrafast mid-IR transient absorption experiments reveal that the long-lived excited states in a number of model compounds are charge transfer states formed by interbase electron transfer, which subsequently decay by charge recombination. The lifetimes of the charge transfer states are surprisingly independent of how the stacked bases are oriented, but disruption of π-stacking, either by elevating temperature or by adding a denaturing co-solvent, completely eliminates this decay channel. Time-resolved emission measurements support the conclusion that these states are populated very rapidly from initial excitons. These experiments also reveal the existence of populations of emissive excited states that decay on the nanosecond time scale. The quantum yield of these states is very small for UVB/UVC excitation, but increases at UVA wavelengths. In double strands, hydrogen bonding between bases perturbs, but does not quench, the long-lived excited states. Kinetic isotope effects on the excited-state dynamics suggest that intrastrand electron transfer may couple to interstrand proton transfer. By revealing how structure and non-covalent interactions affect excited-state dynamics, on-going experimental and theoretical studies of excited states in DNA strands can advance understanding of fundamental photophysics in other nanoscale systems.

  17. Detection of bacteriophage phi 6 minus-strand RNA and novel mRNA isoconformers synthesized in vivo and in vitro, by strand-separating agarose gels

    Energy Technology Data Exchange (ETDEWEB)

    Pagratis, N.; Revel, H.R. (Univ. of Chicago, IL (USA))

    1990-07-01

    Two urea-free agarose gel protocols that resolve the six individual strands of bacteriophage phi 6 dsRNA were developed and used to analyze phage RNA synthesis in vivo and in vitro. Citrate gels separate strands of the large and medium chromosomes while Tris-borate-EDTA (TBE) gels resolve the medium and small dsRNA segments. Minus strands migrate faster than plus strands on citrate gels but are retarded on TBE gels. A study of electrophoretic conditions showed that pH affects strand resolution on citrate gels, and that voltage gradient, agarose concentration, and ethidium bromide significantly alter strand migration on TBE gels. Analysis of native phi 6 RNA synthesized in vivo and in vitro showed that the large and medium message RNAs comigrate with the corresponding plus strands of denatured virion dsRNA. The small messenger RNA is exceptional. Native small mRNA was detected as three isoconformers in vivo and in vitro. The isoconformers were converted by heat denaturation to a single RNA species that comigrates with the virion s+ strand. Minus strands labeled in vivo were detected only after heat denaturation. Minus strand synthesis was detected also in heat-denatured samples from in vitro phi 6 nucleocapsid RNA polymerase reactions at pH values suboptimal for transcription.

  18. Asymmetric Synthesis of (+)-(11 R,12S)-Mefloquine Hydrochloride

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The asymmetric synthesis of (+)-(11R,12S)-mefloquine hydrochloride, an antimalarial drug, was accomplished from commercially available 2-trifluoromethylaniline, ethyl 4,4,4-trifluoroacetoacetate and cyclopentanone in 7 steps with a 14% overall yield. The key steps were proline-catalyzed asymmetric direct aldol reaction and Beck-mann rearrangement. The absolute configuration was assigned by a Mosher's method.

  19. ASYMMETRIC HYDROSILYLATION CATALYZED BY POLYMER—SUPPORTED THIAZOLIDINE RHODIUM CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    LEIYanohui; LIHong; 等

    1999-01-01

    Asymmetric hydrisilylation catalyzed by polymeric thiazolidine rhodium catalysts was conducted.Almost the same optical yields have been obtained when comb-shaped polymeric ligands and their corresponding monomer complexed rhodium cataltysts were used to asymmetric hydrosilylation of acetophenone.Optical yield of chiral 1-methylbenzyl alcohol reaches as high as 71.5%.Temperature dependence of enantioselective hydrosilylation of acetophenone was discussed.

  20. Extensive Taguchi's Quality Loss Function Based On Asymmetric tolerances

    Institute of Scientific and Technical Information of China (English)

    ZHU Wei; LI Yuan-sheng; LIU Feng

    2004-01-01

    If specification interval is asymmetric, basic specification is the target value of quality characteristics. In this paper Taguchi's quality loss function is applied to describe quality loss based on asymmetric tolerances. The measurement of quality loss which is caused by the deviation of quality characteristics from basic specification is further presented.

  1. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    FENG XiaoMing

    2001-01-01

    @@ Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.

  2. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    FENG; XiaoMing

    2001-01-01

    Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.  ……

  3. 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.

  4. Asymmetric catalytic synthesis of the proposed structure of trocheliophorolide B.

    Science.gov (United States)

    Trost, Barry M; Quintard, Adrien

    2012-09-01

    A concise catalytic asymmetric synthesis of the proposed structure of trocheliophorolide B is reported. The synthetic sequence notably features an asymmetric acetaldehyde alkynylation, a Ru-catalyzed alder-ene reaction, and a Zn-ProPhenol ynone aldol condensation. Comparison with the reported data suggests a misassignment of the natural product structure.

  5. Asymmetric group loans, non-assortative matching and adverse selection

    NARCIS (Netherlands)

    Gangopadhyay, Shubhashis; Lensink, Robert

    2014-01-01

    This paper shows that an asymmetric group debt contract, where one borrower co-signs for another, but not vice versa, leads to heterogeneous matching. The analysis suggests that micro finance organizations can achieve the first best by offering asymmetric group contracts. (C) 2014 Elsevier B.V. All

  6. Effect of asymmetric auxin application on Helianthus hypocotyl curvature

    Science.gov (United States)

    Migliaccio, F.; Rayle, D. L.

    1989-01-01

    Indole-3-acetic acid was applied asymmetrically to the hypocotyls of sunflower (Helianthus annuus L.) seedlings. After 5 hours on a clinostat, auxin gradients as small as 1 to 1.3 produced substantial (more than 60 degrees) hypocotyl curvature. This result suggests the asymmetric growth underlying hypocotyl gravitropism can be explained by lateral auxin redistribution.

  7. The invariance of the total direct DNA strand break yield

    Energy Technology Data Exchange (ETDEWEB)

    Bernal, M. A.; Almeida, C. E. de; Sampaio, C.; Incerti, S.; Champion, C.; Nieminen, P. [Laboratorio de Ciencias Radiologicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro 20550-90 (Brazil); Universite Bordeaux 1, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux-Gradignan, CENBG, Chemin du Solarium, BP 120, 33175 Gradignan (France); Laboratoire de Physique Moleculaire et des Collisions, Universite Paul Verlaine-Metz, 1 Boulevard Arago, Technopole 2000, 57078 Metz (France); ESA-ESTEC, 2200 AG Noordwijk (Netherlands)

    2011-07-15

    Purpose: The invariance of the total direct strand break yield when DNA is irradiated by different types of particles and energies has been reported by previous works. This study is intended to explain the physical causes of this behavior. Methods: The geant4-dna extension of the geant4 general purpose Monte Carlo simulation toolkit has been used to determine direct strand break yields induced by protons and alpha particles impacting on a B-DNA geometrical model, including five organization levels of the human genetic material. The linear energy transfer (LET) of such particles ranges from 4.8 keV/{mu}m (10 MeV protons) to about 235 keV/{mu}m (2 MeV alpha particles), at 5.225 {mu}m depth (near the center of the region of interest). Direct total, single and double strand break probabilities have been determined in a liquid water homogeneous medium with a 1.06 g/cm {sup 3} density. The energetic spectra of single strand breaks (SSB), the number of energy deposition events, and the SSB/event ratio were determined. Results: The target-hit probability was found to be independent of both the type and the energy of the incident particle, even if this latter is a secondary electron. This probability is determined by the geometrical properties of the system. The total strand break yield and the number of energy deposition events required to reach a certain absorbed dose were found nearly independent of the type and energy of the incident ion (proton or alpha). In contrast, the double strand break (DSB) yield was found strongly dependent on the LET of the incident radiation. Conclusions: The SSB generation process is homogeneous and independent of the LET of the particles involved, at least within the proton and alpha particle energy range here studied. The target-hit probability is only determined by the ratio between the total volume occupied by targets and that of the ROI where the radiation deposits its energy. The maximum separation distance between two adjacent SSBs to

  8. 蛋白质中strand-loop-strand模体的分类%THE CLASSIFICATION OF STRAND-LOOP-STRAND MOTIFS IN PROTEINS

    Institute of Scientific and Technical Information of China (English)

    高苏娟; 胡秀珍

    2009-01-01

    从蛋白质一级序列出发,以氨基酸紧邻关联为参数,用离散量的方法,采用5交叉检验,对蛋白质中的strand-loop-strand模体进行了分类.文中使用了两个数据库,采用了不同的截取方式和序列模式长,均得到了较好的预测效果.

  9. Polyimides Derived from Novel Asymmetric Benzophenone Dianhydrides

    Science.gov (United States)

    Chuang, Chun-Hua (Inventor)

    2015-01-01

    This invention relates to the composition and processes for preparing thermoset polyimides derived from an asymmetric dianhydride, namely 2,3,3',4'-benzophenone dianhydride (a-BTDA) with at least one diamine, and a monofunctional terminal endcaps. The monofunctional terminating groups include 4-phenylethynylphthalic anhydride ester-acid derivatives, phenylethyl trimellitic anhydride (PETA) and its ester derivatives as well as 3-phenylethynylaniline. The process of polyimide composite comprises impregnating monomer reactants of dianhydride or its ester-acid derivatives, diamine and with monofunctional reactive endcaps into glass, carbon, quartz or synthetic fibers and fabrics, and then stack up into laminates and subsequently heated to between 150-375.degree. C. either at atmosphere or under pressure to promote the curing and crosslinking of the reactive endcaps to form a network of thermoset polyimides.

  10. Asymmetric quantum dialogue in noisy environment

    Science.gov (United States)

    Banerjee, Anindita; Shukla, Chitra; Thapliyal, Kishore; Pathak, Anirban; Panigrahi, Prasanta K.

    2017-02-01

    A notion of asymmetric quantum dialogue (AQD) is introduced. Conventional protocols of quantum dialogue are essentially symmetric as the users (Alice and Bob) can encode the same amount of classical information. In contrast, the proposed scheme for AQD provides different amount of communication powers to Alice and Bob. The proposed scheme offers an architecture, where the entangled state to be used and the encoding scheme to be shared between Alice and Bob depend on the amount of classical information they want to exchange with each other. The general structure for the AQD scheme has been obtained using a group theoretic structure of the operators introduced in Shukla et al. (Phys Lett A 377:518, 2013). The effect of different types of noises (e.g., amplitude damping and phase damping noise) on the proposed scheme is investigated, and it is shown that the proposed scheme for AQD is robust and it uses an optimized amount of quantum resources.

  11. Asymmetric Ferromagnet-Superconductor-Ferromagnet Switch

    Energy Technology Data Exchange (ETDEWEB)

    Cadden-Zimansky, P.; Bazaliy, Ya.B.; Litvak, L.M.; Jiang, J.S.; Pearson, J.; Gu, J.Y.; You, Chun-Yeol; Beasley, M.R.; Bader, S.D.

    2011-11-04

    In layered ferromagnet-superconductor-ferromagnet F{sub 1} /S/F{sub 2} structures, the critical temperature T{sub c} of the superconductors depends on the magnetic orientation of the ferromagnetic layers F{sub 1} and F{sub 2} relative to each other. So far, the experimentally observed magnitude of change in T{sub c} for structures utilizing weak ferromagnets has been 2 orders of magnitude smaller than is expected from calculations. We theoretically show that such a discrepancy can result from the asymmetry of F/S boundaries, and we test this possibility by performing experiments on structures where F{sub 1} and F{sub 2} are independently varied. Our experimental results indicate that asymmetric boundaries are not the source of the discrepancy. If boundary asymmetry is causing the suppressed magnitude of T{sub c} changes, it may only be possible to detect in structures with thinner ferromagnetic layers.

  12. Distributed Function Computation in Asymmetric Communication Scenarios

    CERN Document Server

    Agnihotri, Samar

    2009-01-01

    We consider the distributed function computation problem in asymmetric communication scenarios, where the sink computes some deterministic function of the data split among N correlated informants. The distributed function computation problem is addressed as a generalization of distributed source coding (DSC) problem. We are mainly interested in minimizing the number of informant bits required, in the worst-case, to allow the sink to exactly compute the function. We provide a constructive solution for this in terms of an interactive communication protocol and prove its optimality. The proposed protocol also allows us to compute the worst-case achievable rate-region for the computation of any function. We define two classes of functions: lossy and lossless. We show that, in general, the lossy functions can be computed at the sink with fewer number of informant bits than the DSC problem, while computation of the lossless functions requires as many informant bits as the DSC problem.

  13. Universality in freezing of an asymmetric drop

    Science.gov (United States)

    Ismail, Md Farhad; Waghmare, Prashant R.

    2016-12-01

    We present the evidence of universality in conical tip formation during the freezing of arbitrary-shaped sessile droplets. The focus is to demonstrate the relationship between this universality and the liquid drop shape. We observe that, in the case of asymmetric drops, this universal shape is achieved when the tip reconfigures by changing its location, which subsequently alters the frozen drop shape. The proposed "two-triangle" model quantifies the change in the tip configuration as a function of the asymmetry of the drop that shows a good agreement with the experimental evidence. Finally, based on the experimental and theoretical exercise, we propose the scaling dependence between the variations in the tip configuration and the asymmetry of the drop.

  14. Activation of carboxylic acids in asymmetric organocatalysis.

    Science.gov (United States)

    Monaco, Mattia Riccardo; Poladura, Belén; Diaz de Los Bernardos, Miriam; Leutzsch, Markus; Goddard, Richard; List, Benjamin

    2014-07-01

    Organocatalysis, catalysis using small organic molecules, has recently evolved into a general approach for asymmetric synthesis, complementing both metal catalysis and biocatalysis. Its success relies to a large extent upon the introduction of novel and generic activation modes. Remarkably though, while carboxylic acids have been used as catalyst directing groups in supramolecular transition-metal catalysis, a general and well-defined activation mode for this useful and abundant substance class is still lacking. Herein we propose the heterodimeric association of carboxylic acids with chiral phosphoric acid catalysts as a new activation principle for organocatalysis. This self-assembly increases both the acidity of the phosphoric acid catalyst and the reactivity of the carboxylic acid. To illustrate this principle, we apply our concept in a general and highly enantioselective catalytic aziridine-opening reaction with carboxylic acids as nucleophiles.

  15. THz operation of asymmetric-nanochannel devices

    Science.gov (United States)

    Balocco, C.; Halsall, M.; Vinh, N. Q.; Song, A. M.

    2008-09-01

    The THz spectrum lies between microwaves and the mid-infrared, a region that remains largely unexplored mainly due to the bottleneck issue of lacking compact, solid state, emitters and detectors. Here, we report on a novel asymmetric-nanochannel device, known as the self-switching device, which can operate at frequencies up to 2.5 THz for temperature up to 150 K. This is, to our knowledge, not only the simplest diode but also the quickest acting electronic nanodevice reported to date. The radiation was generated by the free electron laser FELIX (Netherlands). The dependences of the device efficiency as a function of the electric bias, radiation intensity, radiation frequency and temperature are reported.

  16. Isospin dependent properties of asymmetric nuclear matter

    CERN Document Server

    Chowdhury, P Roy; Samanta, C

    2009-01-01

    The density dependence of nuclear symmetry energy is determined from a systematic study of the isospin dependent bulk properties of asymmetric nuclear matter using the isoscalar and the isovector components of density dependent M3Y interaction. The incompressibility $K_\\infty$ for the symmetric nuclear matter, the isospin dependent part $K_{asy}$ of the isobaric incompressibility and the slope $L$ are all in excellent agreement with the constraints recently extracted from measured isotopic dependence of the giant monopole resonances in even-A Sn isotopes, from the neutron skin thickness of nuclei and from analyses of experimental data on isospin diffusion and isotopic scaling in intermediate energy heavy-ion collisions. This work provides a fundamental basis for the understanding of nuclear matter under extreme conditions, and validates the important empirical constraints obtained from recent experimental data.

  17. Chilly Dark Sectors and Asymmetric Reheating

    CERN Document Server

    Adshead, Peter; Shelton, Jessie

    2016-01-01

    In a broad class of theories, the relic abundance of dark matter is determined by interactions internal to a thermalized dark sector, with no direct involvement of the Standard Model (SM). We point out that these theories raise an immediate cosmological question: how was the dark sector initially populated in the early universe? Motivated in part by the difficulty of accommodating large amounts of entropy carried in dark radiation with cosmic microwave background measurements of the effective number of relativistic species at recombination, $N_{\\mathrm{eff}}$, we aim to establish which admissible cosmological histories can populate a thermal dark sector that never reaches thermal equilibrium with the SM. The minimal cosmological origin for such a dark sector is asymmetric reheating, when the same mechanism that populates the SM in the early universe also populates the dark sector at a lower temperature. Here we demonstrate that the resulting inevitable inflaton-mediated scattering between the dark sector and ...

  18. Spectral measurements of asymmetrically irradiated capsule backlighters

    Science.gov (United States)

    Keiter, P. A.; Drake, R. P.

    2016-11-01

    Capsule backlighters provide a quasi-continuum x-ray spectrum over a wide range of photon energies [J. F. Hansen et al., Rev. Sci. Instrum. 79, 013504 (2008)]. Ideally one irradiates the capsule backlighter symmetrically, however, in complex experimental geometries, this is not always possible. In recent experiments we irradiated capsule backlighters asymmetrically and measured the x-ray spectrum from multiple directions. We will present time-integrated spectra over the photon energy range of 2-13 keV and time-resolved spectra over the photon energy range of 2-3 keV. We will compare the spectra from different lines of sight to determine if the laser asymmetry results in an angular dependence in the x-ray emission.

  19. Magnetoresistive system with concentric ferromagnetic asymmetric nanorings

    Energy Technology Data Exchange (ETDEWEB)

    Avila, J. I., E-mail: javila@ulg.ac.be; Tumelero, M. A.; Pasa, A. A.; Viegas, A. D. C. [Laboratório de Filmes Finos e Superfícies (LFFS), Departamento de Física, Universidade Federal de Santa Catarina, CP 476 Florianópolis (Brazil)

    2015-03-14

    A structure consisting of two concentric asymmetric nanorings, each displaying vortex remanent states, is studied with micromagnetic calculations. By orienting in suitable directions, both the asymmetry of the rings and a uniform magnetic field, the vortices chiralities can be switched from parallel to antiparallel, obtaining in this way the analogue of the ferromagnetic and antiferromagnetic configurations found in bar magnets pairs. Conditions on the thickness of single rings to obtain vortex states, as well as formulas for their remanent magnetization are given. The concentric ring structure enables the creation of magnetoresistive systems comprising the qualities of magnetic nanorings, such as low stray fields and high stability. A possible application is as contacts in spin injection in semiconductors, and estimations obtained here of magnetoresistance change for a cylindrical spin injection based device show significant variations comparable to linear geometries.

  20. Asymmetric Beam Combination for Optical Interferometry

    CERN Document Server

    Monnier, J D

    2001-01-01

    Optical interferometers increasingly use single-mode fibers as spatial filters to convert varying wavefront distortion into intensity fluctuations which can be monitored for accurate calibration of fringe amplitudes. Here I propose using an asymmetric coupler to allow the photometric intensities of each telescope beam to be measured at the same time as the fringe visibility, but without the need for dedicated photometric outputs, which reduce the light throughput in the interferometric channels. In the read-noise limited case often encountered in the infrared, I show that a 53% improvement in signal-to-noise ratio for the visibility amplitude measurement is achievable, when compared to a balanced coupler setup with 50% photometric taps (e.g., the FLUOR experiment). In the Poisson-noise limit appropriate for visible light, the improvement is reduced to only ~8%. This scheme also reduces the cost and complexity of the beam combination since fewer components and detectors are required, and can be extended to mor...

  1. Asymmetric EPR entanglement in continuous variable systems

    CERN Document Server

    Wagner, Katherine; Armstrong, Seiji; Morizur, Jean-Francois; Lam, Ping Koy; Bachor, Hans-Albert

    2012-01-01

    Continuous variable entanglement can be produced in nonlinear systems or via interference of squeezed states. In many of optical systems, such as parametric down conversion or interference of optical squeezed states, production of two perfectly symmetric subsystems is usually used for demonstrating the existence of entanglement. This symmetry simplifies the description of the concept of entanglement. However, asymmetry in entanglement may arise naturally in a real experiment, or be intentionally introduced in a given quantum information protocol. These asymmetries can emerge from having the output beams experience different losses and environmental contamination, or from the availability of non-identical input quantum states in quantum communication protocols. In this paper, we present a visualisation of entanglement using quadrature amplitude plots of the twin beams. We quantitatively discuss the strength of asymmetric entanglement using EPR and inseparability criteria and theoretically show that the optimal...

  2. Multi-Quality Properties Capability Analysis for Prestressing Strand of Prestressed Concrete

    Institute of Scientific and Technical Information of China (English)

    Wen; Pei; Sung; Kuen; Suan; Chen; Cheer; Germ; Go

    2002-01-01

    Prestressed concrete structures are main conformati on for the construction of high way bridges. The quality of prestressed concrete s tructures is mainly affected by the tensile strength of prestressing strand. In order to attain the purpose of economic design and long life span of prestressin g strand, the less relaxation property of strand type is suitable for constructi on and usage. Thus, the research and development of prestressing strand is requi red to reach the goals of high tensile strength and ...

  3. Unusual Mortality Events of Harbor Porpoise Strandings in North Carolina, 1997–2009

    OpenAIRE

    Aleta A. Hohn; Rotstein, David S.; Byrd, Barbie L.

    2013-01-01

    A marked increase in the frequency of harbor porpoises (Phocoena phocoena) stranded in North Carolina in 2005 was declared as an Unusual Mortality Event (UME). Strandings occurred in January through May when harbor porpoises are seasonally present. Increased stranding rates were measured relative to a threshold to determine that the UME was occurring. The threshold analysis also revealed elevated strandings during 1999, an undeclared UME year. Recovered carcasses during 1999 and 2005 accounte...

  4. Scaffold of Asymmetric Organic Compounds - Magnetite Plaquettes

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.; Martinez, J.

    2015-01-01

    Life on Earth shows preference towards the set of organics with particular spatial configurations, this 'selectivity' is a crucial criterion for life. With only rare exceptions, life prefers the left- (L-) form over the right- (D-) form of amino acids, resulting in an L-enantiomeric excess (L-ee). Recent studies have shown Lee for alpha-methyl amino acids in some chondrites. Since these amino acids have limited terrestrial occurrence, the origin of their stereoselectivity is nonbiological, and it seems appropriate to conclude that chiral asymmetry, the molecular characteristic that is common to all terrestrial life form, has an abiotic origin. A possible abiotic mechanism that can produce chiral asymmetry in meteoritic amino acids is their formation with the presence of asymmetric catalysts, as mineral crystallization can produce spatially asymmetric structures. Magnetite is shown to be an effective catalyst for the formation of amino acids that are commonly found in chondrites. Magnetite 'plaquettes' (or 'platelets'), first described by Jedwab, show an interesting morphology of barrel-shaped stacks of magnetite disks with an apparent dislocation-induced spiral growth that seem to be connected at the center. A recent study by Singh et al. has shown that magnetites can self-assemble into helical superstructures. Such molecular asymmetry could be inherited by adsorbed organic molecules. In order to understand the distribution of 'spiral' magnetites in different meteorite classes, as well as to investigate their apparent spiral configurations and possible correlation to molecular asymmetry, we observed polished sections of carbonaceous chondrites (CC) using scanning electron microscope (SEM) imaging. The sections were also studied by electron backscattered diffraction (EBSD) in order to reconstruct the crystal orientation along the stack of magnetite disks.

  5. The evolution of cooperation in asymmetric systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Explaining the "Tragedy of the Commons" of the evolution of cooperation remains one of the greatest problems for both biology and social science.Asymmetrical interaction,which is one of the most important characteristics of cooperative systems,has not been sufficiently considered in the existing models of the evolution of cooperation.Considering the inequality in the number and payoff between the cooperative actors and recipients in cooperation systems,discriminative density-dependent interference competition will occur in limited dispersal systems.Our model and simulation show that the local but not the global stability of a cooperative interaction can be maintained if the utilization of common resource remains unsaturated,which can be achieved by density-dependent restraint or competition among the cooperative actors.More intense density dependent interference competition among the cooperative actors and the ready availability of the common resource,with a higher intrinsic contribution ratio of a cooperative actor to the recipient,will increase the probability of cooperation.The cooperation between the recipient and the cooperative actors can be transformed into conflict and,it oscillates chaotically with variations of the affecting factors under different environmental or ecological conditions.The higher initial relatedness(i.e.similar to kin or reciprocity relatedness),which is equivalent to intrinsic contribution ratio of a cooperative actor to the recipient,can be selected for by penalizing less cooperative or cheating actors but rewarding cooperative individuals in asymmetric systems.The initial relatedness is a pivot but not the aim of evolution of cooperation.This explains well the direct conflict observed in almost all cooperative systems.

  6. Special Issue of "Asymmetric Synthesis"%Special Issue of "Asymmetric Synthesis"

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Organic chemistry exploring the world at a molecu- lar level remains essential for our society in the 21st century. Asymmetric synthesis, particularly those em- ploying catalytic approach, is one of the most important research fields in organic synthesis providing chiral compounds in an enantiopure form. The latter is critical since the two enantiomers of one chiral compound, in many cases, have a different response in biological sys- tems. The huge markets of non-racemic chiral com- pounds as synthetic intermediates, pharmaceuticals,

  7. Axially chiral imidodiphosphoric Acid catalyst for asymmetric sulfoxidation reaction: insights on asymmetric induction.

    Science.gov (United States)

    Jindal, Garima; Sunoj, Raghavan B

    2014-04-22

    Insights into chiral induction for an asymmetric sulfoxidation reaction involving a single oxygen atom transfer are gained through analyzing the stereocontrolling transition states. The fitting of the substrate into the chiral cavity of a new class of imidodiphosphoric Brønsted acids, as well as weak CH⋅⋅⋅π and CH⋅⋅⋅O noncovalent interactions, are identified as responsible for the observed chiral induction.

  8. Extended minus-strand DNA as template for R-U5-mediated second-strand transfer in recombinational rescue of primer binding site-modified retroviral vectors

    DEFF Research Database (Denmark)

    Mikkelsen, J G; Lund, Anders Henrik; Dybkaer, K

    1998-01-01

    We have previously demonstrated recombinational rescue of primer binding site (PBS)-impaired Akv murine leukemia virus-based vectors involving initial priming on endogenous viral sequences and template switching during cDNA synthesis to obtain PBS complementarity in second-strand transfer...... of reverse transcription (Mikkelsen et al., J. Virol. 70:1439-1447, 1996). By use of the same forced recombination system, we have now found recombinant proviruses of different structures, suggesting that PBS knockout vectors may be rescued through initial priming on endogenous virus RNA, read......-through of the mutated PBS during minus-strand synthesis, and subsequent second-strand transfer mediated by the R-U5 complementarity of the plus strand and the extended minus-strand DNA acceptor template. Mechanisms for R-U5-mediated second-strand transfer and its possible role in retrovirus replication and evolution...

  9. Torsional regulation of hRPA-induced unwinding of double-stranded DNA

    NARCIS (Netherlands)

    De Vlaminck, I.; Vidic, I.; Van Loenhout, M.T.J.; Kanaar, R.; Lebbink, J.H.G.; Dekker, C.

    2010-01-01

    All cellular single-stranded (ss) DNA is rapidly bound and stabilized by single stranded DNA-binding proteins (SSBs). Replication protein A, the main eukaryotic SSB, is able to unwind double-stranded (ds) DNA by binding and stabilizing transiently forming bubbles of ssDNA. Here, we study the dynamic

  10. Folding DNA origami from a double-stranded source of scaffold

    Science.gov (United States)

    Högberg, Björn; Liedl, Tim; Shih, William M.

    2009-01-01

    Combined heat and chemical denaturation of double-stranded DNA scaffold strands in the presence of staple strands, followed by a sudden temperature drop and then stepwise dialysis to remove the chemical denaturant, leads to self-assembly of two distinct DNA-origami structures. PMID:19566089

  11. 7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false RUS specification for seven wire galvanized steel... steel strand. (a) RUS incorporates by reference ASTM A475-78, Standard Specification for Zinc-Coated Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1,...

  12. Genetic and environmental influence on DNA strand break repair: a twin study

    DEFF Research Database (Denmark)

    Garm, Christian; Moreno-Villanueva, Maria; Bürkle, Alexander;

    2013-01-01

    -strand breaks), and some of the most hazardous lesions (DNA double-strand breaks). DNA damage signaling response (Gamma-H2AX signaling), relative amount of endogenous damage, and DNA-strand break repair capacities were studied in peripheral blood mononuclear cells from 198 twins (94 monozygotic and 104...

  13. 75 FR 28560 - Prestressed Concrete Steel Wire Strand From the People's Republic of China: Final Determination...

    Science.gov (United States)

    2010-05-21

    ... International Trade Administration Prestressed Concrete Steel Wire Strand From the People's Republic of China... less than fair value (``LTFV'') in the antidumping investigation of prestressed concrete steel strand...'' section of this notice. \\1\\ See Prestressed Concrete Steel Wire Strand From the People's Republic of...

  14. 75 FR 32747 - Prestressed Concrete Steel Wire Strand from Mexico: Rescission of Antidumping Duty Administrative...

    Science.gov (United States)

    2010-06-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE INTERNATIONAL TRADE ADMINISTRATION Prestressed Concrete Steel Wire Strand from Mexico: Rescission of Antidumping... prestressed concrete steel wire strand (``PC Strand'') from Mexico for the period January 1, 2009...

  15. Probing electronic coupling between adenine bases in RNA strands from synchrotron radiation circular dichroism experiments

    DEFF Research Database (Denmark)

    Nielsen, Lisbeth Munksgård; Hoffmann, Søren Vrønning; Nielsen, Steen Brøndsted

    2012-01-01

    Circular dichroism spectra (176–330 nm) of RNA adenine oligomers, (rA)n (n = 1–10, 12, 15, and 20), reveal electronic coupling between two bases in short strands. The number of interacting bases in long strands is more and larger than that reported previously for the corresponding DNA strands....

  16. HOMFLY polynomials in representation [3, 1] for 3-strand braids

    Science.gov (United States)

    Mironov, A.; Morozov, A.; Morozov, An.; Sleptsov, A.

    2016-09-01

    This paper is a new step in the project of systematic description of colored knot polynomials started in [1]. In this paper, we managed to explicitly find the inclusive Racah matrix, i.e. the whole set of mixing matrices in channels R ⊗3 -→ Q with all possible Q, for R = [3 , 1]. The calculation is made possible by the use of a newly-developed efficient highest-weight method, still it remains tedious. The result allows one to evaluate and investigate [3 , 1]-colored polynomials for arbitrary 3-strand knots, and this confirms many previous conjectures on various factorizations, universality, and differential expansions. We consider in some detail the next-to-twist-knots three-strand family ( n, -1 | 1 , -1) and deduce its colored HOMFLY. Also confirmed and clarified is the eigenvalue hypothesis for the Racah matrices, which promises to provide a shortcut to generic formulas for arbitrary representations.

  17. Hybrid fur rendering: combining volumetric fur with explicit hair strands

    DEFF Research Database (Denmark)

    Andersen, Tobias Grønbeck; Falster, Viggo; Frisvad, Jeppe Revall

    2016-01-01

    Hair is typically modeled and rendered using either explicitly defined hair strand geometry or a volume texture of hair densities. Taken each on their own, these two hair representations have difficulties in the case of animal fur as it consists of very dense and thin undercoat hairs in combination...... with coarse guard hairs. Explicit hair strand geometry is not well-suited for the undercoat hairs, while volume textures are not well-suited for the guard hairs. To efficiently model and render both guard hairs and undercoat hairs, we present a hybrid technique that combines rasterization of explicitly...... defined guard hairs with ray marching of a prismatic shell volume with dynamic resolution. The latter is the key to practical combination of the two techniques, and it also enables a high degree of detail in the undercoat. We demonstrate that our hybrid technique creates a more detailed and soft fur...

  18. Identification of Cis-Acting Elements on Positive-Strand Subgenomic mRNA Required for the Synthesis of Negative-Strand Counterpart in Bovine Coronavirus

    Directory of Open Access Journals (Sweden)

    Po-Yuan Yeh

    2014-07-01

    Full Text Available It has been demonstrated that, in addition to genomic RNA, sgmRNA is able to serve as a template for the synthesis of the negative-strand [(−-strand] complement. However, the cis-acting elements on the positive-strand [(+-strand] sgmRNA required for (−-strand sgmRNA synthesis have not yet been systematically identified. In this study, we employed real-time quantitative reverse transcription polymerase chain reaction to analyze the cis-acting elements on bovine coronavirus (BCoV sgmRNA 7 required for the synthesis of its (−-strand counterpart by deletion mutagenesis. The major findings are as follows. (1 Deletion of the 5'-terminal leader sequence on sgmRNA 7 decreased the synthesis of the (−-strand sgmRNA complement. (2 Deletions of the 3' untranslated region (UTR bulged stem-loop showed no effect on (−-strand sgmRNA synthesis; however, deletion of the 3' UTR pseudoknot decreased the yield of (−-strand sgmRNA. (3 Nucleotides positioned from −15 to −34 of the sgmRNA 7 3'-terminal region are required for efficient (−-strand sgmRNA synthesis. (4 Nucleotide species at the 3'-most position (−1 of sgmRNA 7 is correlated to the efficiency of (−-strand sgmRNA synthesis. These results together suggest, in principle, that the 5'- and 3'-terminal sequences on sgmRNA 7 harbor cis-acting elements are critical for efficient (−-strand sgmRNA synthesis in BCoV.

  19. Electrostatic Origin of Single-Stranded Genome Packing in Viruses

    Science.gov (United States)

    Belyi, Vladimir; Muthukumar, M.

    2006-03-01

    We develop an electrostatic model for single-stranded RNA/DNA viruses that bind their genome via highly basic semiflexible peptide arms. We show that genome-capsid binding is dominated by non-specific electrostatic interactions, rather than actual amino-acid content. Proposed model explains many universal features of the viral genome. Good agreement is found with wide range of qualified wild-type and mutant viruses.

  20. What Governs the Unzipping Process of Double-Stranded DNA

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Feng; LEI Xiao-Ling; FANG Hai-Ping

    2006-01-01

    @@ The unzipping process of double-stranded DNA is analysed using a discrete model at the base level [Chin. Phys.Lett. 22 (2005)1540]. The numerical results are consistent with the experimental observations on the force-displacement behaviour including the sequence-dependence. We find that the hydrogen bond interaction in a base pair is crucially important to the force-displacement profile.

  1. Five strands of math tasks big book : grades pk-2

    CERN Document Server

    Reed, Nat; Forest, Chris

    2009-01-01

    For grades PK-2, our Common Core State Standards-based resource meets the five strands of math concepts addressed by the NCTM standards and encourages the students to learn and review the concepts in unique ways. Included are challenging problem-solving tasks which will push the boundaries of critical thought and demonstrate to students the importance of mathematical problems in Number & Operations, Geometry, Measurement, Data Analysis & Probability and Algebra using real world situations.

  2. Five strands of math drills big book : grades PK-2

    CERN Document Server

    Reed, Nat; Forest, Chris

    2011-01-01

    For grades PK-2, our Common Core State Standards-based resource meets the five strands of math concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. Included are warm-up and timed drill activities which will push the boundaries of critical thought and demonstrate to students the importance of mathematical problems in Number & Operations, Geometry, Measurement, Data Analysis & Probability and Algebra using real world situations.

  3. Tube Feeding Troubleshooting Guide

    Science.gov (United States)

    Tube Feeding Troubleshoot ing Guide This guide is a tool to assist you, and should not replace your doctor’s ... everyone. table of contents Going Home with Tube Feedings....................................................2 Nausea and ... ...

  4. Electromagnetic ultrasonic guided waves

    CERN Document Server

    Huang, Songling; Li, Weibin; Wang, Qing

    2016-01-01

    This book introduces the fundamental theory of electromagnetic ultrasonic guided waves, together with its applications. It includes the dispersion characteristics and matching theory of guided waves; the mechanism of production and theoretical model of electromagnetic ultrasonic guided waves; the effect mechanism between guided waves and defects; the simulation method for the entire process of electromagnetic ultrasonic guided wave propagation; electromagnetic ultrasonic thickness measurement; pipeline axial guided wave defect detection; and electromagnetic ultrasonic guided wave detection of gas pipeline cracks. This theory and findings on applications draw on the author’s intensive research over the past eight years. The book can be used for nondestructive testing technology and as an engineering reference work. The specific implementation of the electromagnetic ultrasonic guided wave system presented here will also be of value for other nondestructive test developers.

  5. Kid's Guide to Fever

    Science.gov (United States)

    ... in the Operating Room? A Kid's Guide to Fever KidsHealth > For Kids > A Kid's Guide to Fever ... some lighter-weight pajamas. previous continue Fighting a Fever For almost all kids, fevers aren't a ...

  6. Paul Strand y las paradojas de la modernidad americana

    Directory of Open Access Journals (Sweden)

    Vicente Sánchez Biosca

    2010-06-01

    Full Text Available As contribuições de Strand para o cinema estão estreitamente relacionadas com seus trabalhos fotográficos da época e mesmo com um olhar que, apesar de suas múltiplas diferenças, possui muitos pontos em comum. Se em Manhatta (1920, Strand (em colaboração com Sheeler oferece uma síntese da natureza e da modernidade, em Redes (1934 o que predomina, em contrapartida, é a experiência da arte muralista mexicana e a influência de Eisenstein (em suas andanças por México são os fatores que determinam seus esforços na construção de uma épica dos operários. Mas sem dúvida, o projeto mais ambicioso de Strand (ao mando da produtora Frontier Films foi Native Land, o filme que atendeu às demandas do American Popular Front e as moldou nas palavras dos fundadores da pátria americana.

  7. Commercial possibilities for stranded conventional gas from Alaska's North Slope

    Science.gov (United States)

    Attanasi, E.D.; Freeman, P.A.

    2014-01-01

    Stranded gas resources are defined for this study as gas resources in discrete accumulations that are not currently commercially producible, or producible at full potential, for either physical or economic reasons. Approximately 35 trillion cubic feet (TCF) of stranded gas was identified on Alaska’s North Slope. The commercialization of this resource requires facilities to transport gas to markets where sales revenue will be sufficient to offset the cost of constructing and operating a gas delivery system. With the advent of the shale gas revolution, plans for a gas pipeline to the conterminous US have been shelved (at least temporarily) and the State and resource owners are considering a liquefied natural gas (LNG) export project that targets Asian markets. This paper focuses on competitive conditions for Asian gas import markets by estimating delivered costs of competing supplies from central Asia, Russia, Indonesia, Malaysia, and Australia in the context of a range of import gas demand projections for the period from 2020 to 2040. These suppliers’ costs are based on the cost of developing, producing, and delivering to markets tranches of the nearly 600 TCF of recoverable gas from their own conventional stranded gas fields. The results of these analyses imply that Alaska’s gas exports to Asia will likely encounter substantial competitive challenges. The sustainability of Asia’s oil-indexed LNG pricing is also discussed in light of a potentially intense level of competition.

  8. A novel bio-sensor based on DNA strand displacement.

    Directory of Open Access Journals (Sweden)

    Xiaolong Shi

    Full Text Available DNA strand displacement technology performs well in sensing and programming DNA segments. In this work, we construct DNA molecular systems based on DNA strand displacement performing computation of logic gates. Specifically, a class of so-called "DNA neurons" are achieved, in which a "smart" way inspired by biological neurons encoding information is developed to encode and deliver information using DNA molecules. The "DNA neuron" is bistable, that is, it can sense DNA molecules as input signals, and release "negative" or "positive" signals DNA molecules. We design intelligent DNA molecular systems that are constructed by cascading some particularly organized "DNA neurons", which could perform logic computation, including AND, OR, XOR logic gates, automatically. Both simulation results using visual DSD (DNA strand displacement software and experimental results are obtained, which shows that the proposed systems can detect DNA signals with high sensitivity and accretion; moreover, the systems can process input signals automatically with complex nonlinear logic. The method proposed in this work may provide a new way to construct a sensitive molecular signal detection system with neurons spiking behavior in vitro, and can be used to develop intelligent molecular processing systems in vivo.

  9. Euler buckling and nonlinear kinking of double-stranded DNA.

    Science.gov (United States)

    Fields, Alexander P; Meyer, Elisabeth A; Cohen, Adam E

    2013-11-01

    The bending stiffness of double-stranded DNA (dsDNA) at high curvatures is fundamental to its biological activity, yet this regime has been difficult to probe experimentally, and literature results have not been consistent. We created a 'molecular vise' in which base-pairing interactions generated a compressive force on sub-persistence length segments of dsDNA. Short dsDNA strands (Euler buckling'. We monitored the buckling transition via Förster Resonance Energy Transfer (FRET) between appended fluorophores. For low-to-moderate concentrations of monovalent salt (up to ∼150 mM), our results are in quantitative agreement with the worm-like chain (WLC) model of DNA elasticity, without the need to invoke any 'kinked' states. Greater concentrations of monovalent salts or 1 mM Mg(2+) induced an apparent softening of the dsDNA, which was best accounted for by a kink in the region of highest curvature. We tested the effects of all single-nucleotide mismatches on the DNA bending. Remarkably, the propensity to kink correlated with the thermodynamic destabilization of the mismatched DNA relative the perfectly complementary strand, suggesting that the kinked state is locally melted. The molecular vise is exquisitely sensitive to the sequence-dependent linear and nonlinear elastic properties of dsDNA.

  10. Spectroscopic characterization of the interaction of phenosafranin and safranin O with double stranded, heat denatured and single stranded calf thymus DNA.

    Science.gov (United States)

    Saha, Ishita; Kumar, Gopinatha Suresh

    2011-01-01

    Interaction of phenosafranin and safranin O with double stranded, heat denatured and single stranded calf thymus DNA has been studied by fluorescence, absorbance and circular dichroic techniques. Binding to the double stranded and heat denatured DNA conformations induced strong quenching in the fluorescence spectra of both dyes. Linear Scatchard plots indicated the binding to be of one type and the affinity evaluated to be of the order of 10(5) M(-1) with double stranded and heat denatured DNAs. Fluorescence quenching was much weaker with the single stranded DNA and the binding affinity was one order lower. Ferrocyanide quenching studies revealed that the fluorescence emission of the dye molecules bound to the double stranded and heat denatured DNAs was quenched much less compared to that bound to the single stranded DNA. Further, there was significant emission polarization for the bound dyes and strong energy transfer from the DNA base pairs to the dye molecules indicating intercalative binding. Salt dependence of the binding phenomenon revealed that electrostatic forces have significant role in the binding process. The intercalation of these molecules to double stranded and heat denatured DNA and simple stacking to single strands was proved by these fluorescence techniques. Support to the fluorescence results have been derived from absorption and circular dichroic results. Phenosafranin was revealed to be a stronger binding species compared to safranin O.

  11. Autonomous parvovirus LuIII encapsidates equal amounts of plus and minus DNA strands

    Energy Technology Data Exchange (ETDEWEB)

    Bates, R.C.; Snyder, C.E.; Banerjee, P.T.; Mitra, S.

    1984-02-01

    Autonomous parvoviruses are thought to uniquely encapsidate single-stranded DNA of minus polarity. In contrast, the defective adeno-associated viruses separately encapsidate equal amounts of plus and minus DNA strands. The uniqueness of minus strand encapsidation is reexamined for the autonomous parvoviruses. Although it was found that Kilham rat virus and H-1 virus encapsidate varying but small amounts of complementary-strand DNA, it was unexpected to find that LuIII virus encapsidated equal amounts of plus and minus DNA. The extracted LuIII DNA possessed properties of double-stranded replicative-form DNA, including insensitivity to S1 endonuclease, cleavage by restriction enzymes, and conversion to unit-length, single-stranded DNA when electrophoresed under denaturing conditions. However, the inability of this DNA to form single-stranded DNA circles when denatured and then renatured in the presence of formamide and the lack of double-stranded DNA circle formation after treatment with exonuclease III and reannealing shows a lack of sequence homology of the 3' and 5' termini of LuIII DNA, in contrast to adeno-associated virus DNA. Digestion of LuIII double-stranded DNA with EcoRI and HincII and separation of plus and minus DNA strands on composite agarose-acrylamide gels identified a heterogeneity present only in the plus DNA strand. These results suggest that strand specificity of viral DNA encapsidation is not a useful property for differentiation between the autonomous and defective parvoviruses. Furthermore, encapsidation by LuIII of equal amounts of complementary DNA strands in contrast to encapsidation of minus strands by H-1 virus, when propagated in the same host cell type, suggests that selection of strands for encapsidation is a virus-coded rather than host-controlled event.

  12. Stranding of Two Sperm Whales (Physeter macrocephalus) in the “North Sea Trap” at Henne Strand, Denmark

    DEFF Research Database (Denmark)

    Hansen, Mette Siv; Alstrup, Aage Kristian Olsen; Hansen, Jørgen H.

    2016-01-01

    In February 2014 two male sperm whales (Physeter macrocephalus) stranded at Henne Strand, Denmark. One whale (MCE 1644) was found dead, while the other (MCE 1645) was still alive, but drowned during the high tide. To increase our knowledge of sperm whales, conduct forage investigations, post......-mortem and diagnostic examinations were carried out. The decay of the carcasses progressed quickly. The whales had large (MCE 1644) or moderate (MCE 1645) numbers of squid beaks (Gonatus fabricii) in the stomachventricles, but no evidence of recentfresh feeding. Both whales had acute dermatitis probably due to trauma...... severe localized or systemic infections. The finding of large volumes of bloody pleural fluid with large quantities of C. septicum suggests that MCE 1644 died of infection. However, reservations must be taken due to the pronounced decay of the carcass. Sperm whales have strong social bonds where...

  13. Cetacean stranding records in the Turkish Western Black Sea coast during October 2012 - September 2013

    Directory of Open Access Journals (Sweden)

    Arda M. Tonay

    2016-11-01

    Full Text Available Between October 2012 and September 2013, a research has been conducted on marine mammal strandings on Turkish western Black Sea coast. In total, 54 stranded cetaceans were found, which included 22 bottlenose dolphins (41%, 19 harbour porpoises (35%, 11 common dolphins (20%, and 4% unidentified individuals. Most strandings were observed in May and June. Bycaught carcases were found especially in April, June and July. The aim of the study is to collect first-hand data on the monthly stranding rates in order to understand the seasonal variation of stranding cases in a year.

  14. Bottlenose dolphin (Tursiops truncatus) strandings in South Carolina, 1992-1996

    OpenAIRE

    McFee, Wayne E.; Hopkins-Murphy, Sally R.

    2002-01-01

    From 1992 to 1996, 153 bottlenose dolphin stranded in South Carolina, accounting for 73% of all marine mammal strandings during this period. The objectives of our study were to evaluate data from these strandings to deter-mine 1) annual trends in strandings, 2) seasonal and spatial distribution trends, 3) life history parameters such as sex ratio and age classes, 3) seasonal trends in reproduction, and 4) the extent to which humans have played a role in causing these strandings (human inter-a...

  15. Ultrasound-Guided Breast Biopsy

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Ultrasound-Guided Breast Biopsy An ultrasound-guided breast biopsy ... limitations of Ultrasound-Guided Breast Biopsy? What is Ultrasound-Guided Breast Biopsy? Lumps or abnormalities in the ...

  16. The isothermal amplification detection of double-stranded DNA based on a double-stranded fluorescence probe.

    Science.gov (United States)

    Shi, Chao; Shang, Fanjin; Pan, Mei; Liu, Sen; Ma, Cuiping

    2016-06-15

    Here we have developed a novel method of isothermal amplification detection of double-stranded DNA (dsDNA) based on double-stranded fluorescence probe (ds-probe). Target dsDNA repeatedly generated single-stranded DNA (ssDNA) with polymerase and nicking enzyme. The ds-probe as a primer hybridized with ssDNA and extended to its 5'-end. The displaced ssDNA served as a new detection target to initiate above-described reaction. Meanwhile, the extended ds-probe could dynamically dissociate from ssDNA and self-hybridize, converting into a turn-back structure to initiate another amplification reaction. In particular, the ds-probe played a key role in the entire experimental process, which not only was as a primer but also produced the fluorescent signal by an extension and displacement reaction. Our method could detect the pBluescript II KS(+) plasmid with a detection limit of 2.3 amol, and it was also verified to exhibit a high specificity, even one-base mismatch. Overall, it was a true isothermal dsDNA detection strategy with a strongly anti-jamming capacity and one-pot, only requiring one ds-probe, which greatly reduced the cost and the probability of contamination. With its advantages, the approach of dsDNA detection will offer a promising tool in the field of point-of-care testing (POCT).

  17. Experimental study on the ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands

    CERN Document Server

    Iwakuma, M; Funaki, K

    2002-01-01

    The ac loss properties of two-strand superconducting parallel conductors were experimentally investigated by using NbTi multifilamentary strands with a rectangular cross section. We prepared the simple situation that was supposed in the previous theoretical study (M Iwakuma et al 2002 Supercond. Sci. Technol. 15 1525-36). The two insulated strands were sparsely co-wound into one-layer solenoidal coils. They were transposed only once and soldered at both ends. The ac losses in the sample coils were measured by a pick-up-coil method by applying uniform ac magnetic field parallel to the coil axis and comparing it with the theoretical results. The validity of the theoretical expressions derived in the previous paper was verified by the quantitative agreement with experiment in all the aspects, i.e. the dependencies on frequency, field amplitude and the deviation length in transposition in both the non-saturation and saturation cases and also the threshold condition between them. The results obtained support the t...

  18. Simulation of Chaos in Asymmetric Nonlinear Chua's Circuit

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-fei; QIAO Shu-tong; JIANG Jian-guo

    2008-01-01

    In order to describe practical chaotic systems exactly, we presented a simple modified Chua's circuit,which contains an asymmetric nonlinear resistive element. Mathematical analysis was made, and simulation study was performed by MATLAB. By varying the value of linear resistor in the circuit, rich variety dynamical behaviors were observed, such as DC equilibrium point, Hopf bifurcation, period-doubling bifurcation,single-scroll strange attractor, periodic windows, and asymmetric double-scroll strange attractor. The extreme sensitivity in the state trajectory with respect to the initial conditions was exhibited; the special characteristic of asymmetric nonlinear Chua's circuit was found also.

  19. The Dualism of Asymmetric Information in Agricultural Insurance

    Directory of Open Access Journals (Sweden)

    Xuemei Yang

    2013-07-01

    Full Text Available Asymmetric information objectively exists in the insurance market, especially in agricultural insurance, which has a great impact on the insurance contract and market operation. This paper designs two game models to analyse the dualism of asymmetric information in agricultural insurance and its reasons of forming. We find that, the particularity of agricultural production, the agricultural risk diversification and the benefits’ spillover of the agricultural insurance are the main causes of asymmetric information. Therefore, this paper puts forward that establishment of appropriate agricultural insurance mode, optimization of insurance policy design and increasing investment in science and technology, increasing farmers’ insurance consciousness and establishing supervision system

  20. Asymmetric Orbifolds, Noncommutative Geometry and Type I String Vacua

    CERN Document Server

    Blumenhagen, R; Körs, B; Lüst, Dieter; Blumenhagen, Ralph; Goerlich, Lars; Kors, Boris; Lust, Dieter

    2000-01-01

    We investigate the D-brane contents of asymmetric orbifolds. Using T-dualitywe find that the consistent description of open strings in asymmetric orbifoldsrequires to turn on background gauge fields on the D-branes. Hence open stringsand D-branes in generic asymmetric orbifolds necessarily lead to noncommutativegeometry. We derive the corresponding noncommutative geometry arising on suchD-branes with mixed Neumann-Dirichlet boundary conditions by applying anasymmetric rotation to ordinary D-branes with pure Dirichlet boundaryconditions. As a concrete application of our results we construct asymmetrictype I vacua requiring open strings with mixed boundary conditions for tadpolecancellation.

  1. Mechanisms of asymmetric cell divisions in Drosophila melanogaster neuroblasts

    Directory of Open Access Journals (Sweden)

    X Jiang

    2014-04-01

    Full Text Available Stem cells possess the properties of self-renewal and differentiation, and mainly rely on two strategies for division, including symmetric and asymmetric cell divisions. In this review, we summarize the latest progress on asymmetric cell divisions in Drosophila melanogaster neuroblasts (NBs, which focus on the establishment of cell polarity, mitotic spindle orientation, the asymmetric segregation of cell fate determinants as well as cell-cycle control. Here we also introduce five major cell fate determinants, including Numb, Prospero, Brat, Miranda, and Pon, which are thought to be unequally segregated to the ganglion mother cells (GMCs and play an important role in the formation of stem cell-derived tumors

  2. Generic approach for synthesizing asymmetric nanoparticles and nanoassemblies

    Science.gov (United States)

    Sun, Yugang; Hu, Yongxing

    2015-05-26

    A generic route for synthesis of asymmetric nanostructures. This approach utilizes submicron magnetic particles (Fe.sub.3O.sub.4--SiO.sub.2) as recyclable solid substrates for the assembly of asymmetric nanostructures and purification of the final product. Importantly, an additional SiO.sub.2 layer is employed as a mediation layer to allow for selective modification of target nanoparticles. The partially patched nanoparticles are used as building blocks for different kinds of complex asymmetric nanostructures that cannot be fabricated by conventional approaches. The potential applications such as ultra-sensitive substrates for surface enhanced Raman scattering (SERS) have been included.

  3. The experimental study of acoustic field in an asymmetric borehole

    Institute of Scientific and Technical Information of China (English)

    LINWeijun; ZHANGChengyu; ZHANGHailan; WANGXiuming

    2003-01-01

    The acoustic field in an asymmetric borehole was investigated by recording and comparing the waveforms with different offset in both axial symmetric borehole and axial asymmetric borehole. The two-dimensional spectrum in wave-number and frequency domain was also calculated and compared with the result of numeric simulation with 2.5-D finite difference method, and a consistent result was obtained. This work provides an accurate verification of our investigation of asymmetric borehole with 2.5-D finite difference method.

  4. High-Voltage, Asymmetric-Waveform Generator

    Science.gov (United States)

    Beegle, Luther W.; Duong, Tuan A.; Duong, Vu A.; Kanik, Isik

    2008-01-01

    The shapes of waveforms generated by commercially available analytical separation devices, such as some types of mass spectrometers and differential mobility spectrometers are, in general, inadequate and result in resolution degradation in output spectra. A waveform generator was designed that would be able to circumvent these shortcomings. It is capable of generating an asymmetric waveform, having a peak amplitude as large as 2 kV and frequency of several megahertz, which can be applied to a capacitive load. In the original intended application, the capacitive load would consist of the drift plates in a differential-mobility spectrometer. The main advantage to be gained by developing the proposed generator is that the shape of the waveform is made nearly optimum for various analytical devices requiring asymmetric-waveform such as differential-mobility spectrometers. In addition, this waveform generator could easily be adjusted to modify the waveform in accordance with changed operational requirements for differential-mobility spectrometers. The capacitive nature of the load is an important consideration in the design of the proposed waveform generator. For example, the design provision for shaping the output waveform is based partly on the principle that (1) the potential (V) on a capacitor is given by V=q/C, where C is the capacitance and q is the charge stored in the capacitor; and, hence (2) the rate of increase or decrease of the potential is similarly proportional to the charging or discharging current. The proposed waveform generator would comprise four functional blocks: a sine-wave generator, a buffer, a voltage shifter, and a high-voltage switch (see Figure 1). The sine-wave generator would include a pair of operational amplifiers in a feedback configuration, the parameters of which would be chosen to obtain a sinusoidal timing signal of the desired frequency. The buffer would introduce a slight delay (approximately equal to 20 ns) but would otherwise

  5. Insertional Mutagenesis by CRISPR/Cas9 Ribonucleoprotein Gene Editing in Cells Targeted for Point Mutation Repair Directed by Short Single-Stranded DNA Oligonucleotides.

    Science.gov (United States)

    Rivera-Torres, Natalia; Banas, Kelly; Bialk, Pawel; Bloh, Kevin M; Kmiec, Eric B

    2017-01-01

    CRISPR/Cas9 and single-stranded DNA oligonucleotides (ssODNs) have been used to direct the repair of a single base mutation in human genes. Here, we examine a method designed to increase the precision of RNA guided genome editing in human cells by utilizing a CRISPR/Cas9 ribonucleoprotein (RNP) complex to initiate DNA cleavage. The RNP is assembled in vitro and induces a double stranded break at a specific site surrounding the mutant base designated for correction by the ssODN. We use an integrated mutant eGFP gene, bearing a single base change rendering the expressed protein nonfunctional, as a single copy target in HCT 116 cells. We observe significant gene correction activity of the mutant base, promoted by the RNP and single-stranded DNA oligonucleotide with validation through genotypic and phenotypic readout. We demonstrate that all individual components must be present to obtain successful gene editing. Importantly, we examine the genotype of individually sorted corrected and uncorrected clonally expanded cell populations for the mutagenic footprint left by the action of these gene editing tools. While the DNA sequence of the corrected population is exact with no adjacent sequence modification, the uncorrected population exhibits heterogeneous mutagenicity with a wide variety of deletions and insertions surrounding the target site. We designate this type of DNA aberration as on-site mutagenicity. Analyses of two clonal populations bearing specific DNA insertions surrounding the target site, indicate that point mutation repair has occurred at the level of the gene. The phenotype, however, is not rescued because a section of the single-stranded oligonucleotide has been inserted altering the reading frame and generating truncated proteins. These data illustrate the importance of analysing mutagenicity in uncorrected cells. Our results also form the basis of a simple model for point mutation repair directed by a short single-stranded DNA oligonucleotides and

  6. Insertional Mutagenesis by CRISPR/Cas9 Ribonucleoprotein Gene Editing in Cells Targeted for Point Mutation Repair Directed by Short Single-Stranded DNA Oligonucleotides

    Science.gov (United States)

    Rivera-Torres, Natalia; Bialk, Pawel; Bloh, Kevin M.; Kmiec, Eric B.

    2017-01-01

    CRISPR/Cas9 and single-stranded DNA oligonucleotides (ssODNs) have been used to direct the repair of a single base mutation in human genes. Here, we examine a method designed to increase the precision of RNA guided genome editing in human cells by utilizing a CRISPR/Cas9 ribonucleoprotein (RNP) complex to initiate DNA cleavage. The RNP is assembled in vitro and induces a double stranded break at a specific site surrounding the mutant base designated for correction by the ssODN. We use an integrated mutant eGFP gene, bearing a single base change rendering the expressed protein nonfunctional, as a single copy target in HCT 116 cells. We observe significant gene correction activity of the mutant base, promoted by the RNP and single-stranded DNA oligonucleotide with validation through genotypic and phenotypic readout. We demonstrate that all individual components must be present to obtain successful gene editing. Importantly, we examine the genotype of individually sorted corrected and uncorrected clonally expanded cell populations for the mutagenic footprint left by the action of these gene editing tools. While the DNA sequence of the corrected population is exact with no adjacent sequence modification, the uncorrected population exhibits heterogeneous mutagenicity with a wide variety of deletions and insertions surrounding the target site. We designate this type of DNA aberration as on-site mutagenicity. Analyses of two clonal populations bearing specific DNA insertions surrounding the target site, indicate that point mutation repair has occurred at the level of the gene. The phenotype, however, is not rescued because a section of the single-stranded oligonucleotide has been inserted altering the reading frame and generating truncated proteins. These data illustrate the importance of analysing mutagenicity in uncorrected cells. Our results also form the basis of a simple model for point mutation repair directed by a short single-stranded DNA oligonucleotides and

  7. Metallographic investigation of fracture behavior in ITER-style Nb$_{3}$Sn superconducting strands

    CERN Document Server

    Jewell, M C; Larbalestier, D C; Nijhuis, A

    2009-01-01

    In this work we specify the extent to which fracture in two ITER-style Nb3Sn composite strands occurs in a collective or individual manner, under mechanical tension and bending from the TARSIS apparatus at the University of Twente. A bronze-route strand from European Advanced Superconductors (EAS), which has very uniform, well-spaced filaments, has a widely distributed (200 μm) fracture field and exhibits a composite of individual and collective cracks. An internal tin strand from Oxford Instruments – Superconducting Technology (OST) demonstrates much more localized, collective fracture behavior. The filaments in this strand are about four times larger (in area) than the filaments in the EAS strand, and also agglomerate significantly during heat treatment upon conversion of the Nb to Nb3Sn. These results demonstrate that the architecture of the strand can play a significant role in determining the mechanical toughness of the composite, and that strand design should incorporate mechanical considerations in ...

  8. Programmable DNA-Guided Artificial Restriction Enzymes.

    Science.gov (United States)

    Enghiad, Behnam; Zhao, Huimin

    2017-02-06

    Restriction enzymes are essential tools for recombinant DNA technology that have revolutionized modern biological research. However, they have limited sequence specificity and availability. Here we report a Pyrococcus furiosus Argonaute (PfAgo) based platform for generating artificial restriction enzymes (AREs) capable of recognizing and cleaving DNA sequences at virtually any arbitrary site and generating defined sticky ends of varying length. Short DNA guides are used to direct PfAgo to target sites for cleavage at high temperatures (>87 °C) followed by reannealing of the cleaved single stranded DNAs. We used this platform to generate over 18 AREs for DNA fingerprinting and molecular cloning of PCR-amplified or genomic DNAs. These AREs work as efficiently as their naturally occurring counterparts, and some of them even do not have any naturally occurring counterparts, demonstrating easy programmability, generality, versatility, and high efficiency for this new technology.

  9. Chlamydia trachomatis CT771 (nudH) is an asymmetric Ap4A hydrolase

    Science.gov (United States)

    Barta, Michael L.; Lovell, Scott; Sinclair, Amy N.; Battaile, Kevin P.; Hefty, P. Scott

    2014-01-01

    Asymmetric diadenosine 5′,5′″-P1,P4-tetraphosphate (Ap4A) hydrolases are members of the Nudix superfamily that asymmetrically cleave the metabolite Ap4A into ATP and AMP while facilitating homeostasis. The obligate intracellular mammalian pathogen Chlamydia trachomatis possesses a single Nudix family protein, CT771. As pathogens that rely on a host for replication and dissemination typically have one or zero Nudix family proteins, this suggests that CT771 could be critical for chlamydial biology and pathogenesis. We identified orthologs to CT771 within environmental Chlamydiales that share active site residues suggesting a common function. Crystal structures of both apo- and ligand-bound CT771 were determined to 2.6 Å and 1.9 Å resolution, respectively. The structure of CT771 shows a αβα-sandwich motif with many conserved elements lining the putative Nudix active site. Numerous aspects of the ligand-bound CT771 structure mirror those observed in the ligand-bound structure of the Ap4A hydrolase from Caenorhabditis elegans. These structures represent only the second Ap4A hydrolase enzyme member determined from eubacteria and suggest that mammalian and bacterial Ap4A hydrolases might be more similar than previously thought. The aforementioned structural similarities, in tandem with molecular docking, guided the enzymatic characterization of CT771. Together, these studies provide the molecular details for substrate binding and specificity, supporting the analysis that CT771 is an Ap4A hydrolase (nudH). PMID:24354275

  10. Kinetic signatures of the region surrounding the X line in asymmetric (magnetopause) reconnection

    Science.gov (United States)

    Shay, M. A.; Phan, T. D.; Haggerty, C. C.; Fujimoto, M.; Drake, J. F.; Malakit, K.; Cassak, P. A.; Swisdak, M.

    2016-05-01

    Kinetic particle-in-cell simulations are used to identify signatures of the electron diffusion region (EDR) and its surroundings during asymmetric magnetic reconnection. A "shoulder" in the sunward pointing normal electric field (EN > 0) at the reconnection magnetic field reversal is a good indicator of the EDR and is caused by magnetosheath electron meandering orbits in the vicinity of the X line. Earthward of the X line, electrons accelerated by EN form strong currents and crescent-shaped distribution functions in the plane perpendicular to B. Just downstream of the X line, parallel electric fields create field-aligned crescent electron distribution functions. In the immediate upstream magnetosheath, magnetic field strength, plasma density, and perpendicular electron temperatures are lower than the asymptotic state. In the magnetosphere inflow region, magnetosheath ions intrude resulting in an Earthward pointing electric field and parallel heating of magnetospheric particles. Many of the above properties persist with a guide field of at least unity.

  11. Cells as Active Particles in Asymmetric Potentials: Motility under External Gradients

    Science.gov (United States)

    Comelles, Jordi; Caballero, David; Voituriez, Raphaël; Hortigüela, Verónica; Wollrab, Viktoria; Godeau, Amélie Luise; Samitier, Josep; Martínez, Elena; Riveline, Daniel

    2014-01-01

    Cell migration is a crucial event during development and in disease. Mechanical constraints and chemical gradients can contribute to the establishment of cell direction, but their respective roles remain poorly understood. Using a microfabricated topographical ratchet, we show that the nucleus dictates the direction of cell movement through mechanical guidance by its environment. We demonstrate that this direction can be tuned by combining the topographical ratchet with a biochemical gradient of fibronectin adhesion. We report competition and cooperation between the two external cues. We also quantitatively compare the measurements associated with the trajectory of a model that treats cells as fluctuating particles trapped in a periodic asymmetric potential. We show that the cell nucleus contributes to the strength of the trap, whereas cell protrusions guided by the adhesive gradients add a constant tunable bias to the direction of cell motion. PMID:25296303

  12. Evacuation dynamics of asymmetrically coupled pedestrian pairs

    CERN Document Server

    Müller, Frank

    2016-01-01

    We propose and analyze extended floor field cellular automaton models for evacuation dynamics of inhomogeneous pedestrian pairs which are coupled by asymmetric group interactions. Such pairs consist of a leader, who mainly determines the couple's motion and a follower, who has a defined tendency to follow the leader. Examples for such pairs are mother and child or two siblings of different age. We examine the system properties and compare them to the case of a homogeneous crowd. We find a strong impact on evacuation times for the regime of strong pair coupling due to the occurrence of a clogging phenomenon. In addition we obtain a non-trivial dependence of evacuation times on the followers' coupling to the static floor field, which carries the information of the shortest way to the exit location. In particular we find that systems with fully passive followers, who are solely coupled to their leaders, show lower evacuation times than homogeneous systems where all pedestrians have an equal tendency to move towa...

  13. Asymmetric vector mesons produced in nuclear collisions

    CERN Document Server

    Dremin, I M

    2016-01-01

    It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further detalized in quantum mechanics as the interference of direct and continuum states in Fano-Feshbach effect. To reveal the nature of the interaction it is proposed to use a phenomenological model of the additional contribution due to Cherenkov gluons. They can be created because of the excess of the refractivity index over 1 just in the low-mass wing as required by the classical Cherenkov treatment. In quantum mechanics, this requirement is related to the positive real part of the interaction ...

  14. ADMonium: Asymmetric Dark Matter Bound State

    CERN Document Server

    Bi, Xiao-Jun; Ko, P; Li, Jinmian; Li, Tianjun

    2016-01-01

    We propose a novel framework for asymmetric scalar dark matter (ADM), which has interesting collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local $U(1)_d$ symmetry which is broken at a low scale and provides a light gauge boson $X$. The dark gauge coupling is strong and then ADM can annihilate away into $X$-pair effectively. Therefore, the ADM can form bound state due to its large self-interaction via $X$ mediation. To explore the collider signature of ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can have a sizable mixing with the heavier Higgs boson, which admits a large cross section of ADMonium production associated with $b\\bar b$. Of particular interest, our setup nicely explains the recent di-photon anomaly at 750 GeV via the events from ${\\rm ADMonium}\\ra 2X(\\ra e^+e^-)$, where the electrons are identified as ...

  15. Asymmetric vector mesons produced in nuclear collisions

    Science.gov (United States)

    Dremin, I. M.; Nechitailo, V. A.

    2016-09-01

    It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high-energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further described in quantum mechanics as the interference of direct and continuum states in the Fano-Feshbach effect. To reveal the nature of the interaction it is proposed to use a phenomenological model of the additional contribution due to Cherenkov gluons. They can be created because of the excess of the refractivity index over 1 just in the low-mass wing as required by the classical Cherenkov treatment. In quantum mechanics, this requirement is related to the positive real part of the interaction amplitude in this wing. The corresponding parameters are found from the comparison with ρ-meson data and admit reasonable explanation.

  16. Barbed congruence of the asymmetric chi calculus

    Institute of Scientific and Technical Information of China (English)

    DONG Xiao-ju; FU Yu-xi

    2006-01-01

    The chi calculus is a model of mobile processes. It has evolved from the pi-calculus with motivations from simplification and communication-as-cut-elimination. This paper studies the chi calculus in the framework incorporating asymmetric communication. The major feature of the calculus is the identification of two actions:x/x and τ. The investigation on the barbed bisimilarity shows how the property affects the observational theory.Based on the definition of the barbed bisimilarity, the simulation properties of the barbed bisimilarity are studied. It shows that the algebraic properties of the barbed bisimilarity have changed greatly compared with the chi calculus. Although the definition of the barbed bisimilarity is very simple, the property of closeness under contexts makes it difficult to understand the barbed bisimilarity directly. Therefore an open style definition of the barbed bisimilarity is given, which is a context free description of barbed bisimilarity. Its definition is complex,but it is a well-behaved relation for it coincides with the barbed bisimilarity. It also helps to build an axiomatization system for the barbed congruence. Besides the axioms for the strong barbed bisimilarity, the paper proposes a new tau law and four new update laws for the barbed congruence. Both the operational and algebraic properties of the enriched calculus improve the understanding of the bisimulation behaviors of the model.

  17. Magnetohydrodynamic Waves in an Asymmetric Magnetic Slab

    Science.gov (United States)

    Allcock, Matthew; Erdélyi, Robert

    2017-02-01

    Analytical models of solar atmospheric magnetic structures have been crucial for our understanding of magnetohydrodynamic (MHD) wave behaviour and in the development of the field of solar magneto-seismology. Here, an analytical approach is used to derive the dispersion relation for MHD waves in a magnetic slab of homogeneous plasma enclosed on its two sides by non-magnetic, semi-infinite plasma with different densities and temperatures. This generalises the classic magnetic slab model, which is symmetric about the slab. The dispersion relation, unlike that governing a symmetric slab, cannot be decoupled into the well-known sausage and kink modes, i.e. the modes have mixed properties. The eigenmodes of an asymmetric magnetic slab are better labelled as quasi-sausage and quasi-kink modes. Given that the solar atmosphere is highly inhomogeneous, this has implications for MHD mode identification in a range of solar structures. A parametric analysis of how the mode properties (in particular the phase speed, eigenfrequencies, and amplitudes) vary in terms of the introduced asymmetry is conducted. In particular, avoided crossings occur between quasi-sausage and quasi-kink surface modes, allowing modes to adopt different properties for different parameters in the external region.

  18. Asymmetric vector mesons produced in nuclear collisions

    Energy Technology Data Exchange (ETDEWEB)

    Dremin, I.M.; Nechitailo, V.A. [Lebedev Physical Institute, Moscow (Russian Federation); National Research Nuclear University ' ' MEPhI' ' , Moscow (Russian Federation)

    2016-09-15

    It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high-energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further described in quantum mechanics as the interference of direct and continuum states in the Fano-Feshbach effect. To reveal the nature of the interaction it is proposed to use a phenomenological model of the additional contribution due to Cherenkov gluons. They can be created because of the excess of the refractivity index over 1 just in the low-mass wing as required by the classical Cherenkov treatment. In quantum mechanics, this requirement is related to the positive real part of the interaction amplitude in this wing. The corresponding parameters are found from the comparison with ρ-meson data and admit reasonable explanation. (orig.)

  19. Asymmetric Swiss-cheese brane-worlds

    Science.gov (United States)

    Gergely, László Á.; Képíró, Ibolya

    2007-07-01

    We study a brane-world cosmological scenario with local inhomogeneities represented by black holes. The brane is asymmetrically embedded into the bulk. The black strings/cigars penetrating the Friedmann brane generate a Swiss-cheese-type structure. This universe forever expands and decelerates, as its general relativistic analogue. The evolution of the cosmological fluid, however, can proceed along four branches, two allowed to have positive energy density, and one of them having the symmetric embedding limit. On this branch a future pressure singularity can arise for either (a) a difference in the cosmological constants of the cosmological and black hole brane regions or (b) a difference in the left and right bulk cosmological constants. While behaviour (a) can be avoided by a redefinition of the fluid variables, (b) establishes a critical value of the asymmetry over which the pressure singularity occurs. We introduce the pressure singularity censorship which bounds the degree of asymmetry in the bulk cosmological constant. We also show as a model-independent generic feature that the asymmetry source term due to the bulk cosmological constant increases in the early universe. In order to obey the nucleosynthesis constraints, the brane tension should be constrained therefore both from below and from above. With the maximal degree of asymmetry obeying the pressure singularity censorship, the higher limit is ten times the lower limit. The degree of asymmetry allowed by present cosmological observations is, however, much less, pushing the upper limit to infinity.

  20. The Asymmetric Pupil Fourier Wavefront Sensor

    CERN Document Server

    Martinache, Frantz

    2013-01-01

    This paper introduces a novel wavefront sensing approach that relies on the Fourier analysis of a single conventional direct image. In the high Strehl ratio regime, the relation between the phase measured in the Fourier plane and the wavefront errors in the pupil can be linearized, as was shown in a previous work that introduced the notion of generalized closure-phase, or kernel-phase. The technique, to be usable as presented requires two conditions to be met: (1) the wavefront errors must be kept small (of the order of one radian or less) and (2) the pupil must include some asymmetry, that can be introduced with a mask, for the problem to become solvable. Simulations show that this asymmetric pupil Fourier wavefront sensing or APF-WFS technique can improve the Strehl ratio from 50 to over 90 % in just a few iterations, with excellent photon noise sensitivity properties, suggesting that on-sky close loop APF-WFS is possible with an extreme adaptive optics system.

  1. Asymmetric Electrostatic Radiation Shielding for Spacecraft

    Science.gov (United States)

    Metzger, Philip T.; Youngquist, Robert C.; Lane, John E.

    2005-01-01

    A paper describes the types, sources, and adverse effects of energetic-particle radiation in interplanetary space, and explores a concept of using asymmetric electrostatic shielding to reduce the amount of such radiation impinging on spacecraft. Typically, such shielding would include a system of multiple inflatable, electrically conductive spheres deployed in clusters in the vicinity of a spacecraft on lightweight structures that would maintain the spheres in a predetermined multipole geometry. High-voltage generators would maintain the spheres at potential differences chosen in conjunction with the multipole geometry so that the resulting multipole field would gradually divert approaching energetic atomic nuclei from a central region occupied by the spacecraft. The spheres nearest the center would be the most positive, so as to repel the positively charged impinging nuclei from the center. At the same time, the monopole potential of the overall spacecraft-and-shielding system would be made negative so as to repel thermal electrons. The paper presents results of computational simulations of energetic-particle trajectories and shield efficiency for a trial system of 21 spheres arranged in three clusters in an overall linear quadrupole configuration. Further development would be necessary to make this shielding concept practical.

  2. Asymmetric translation between multiple representations in chemistry

    Science.gov (United States)

    Lin, Yulan I.; Son, Ji Y.; Rudd, James A., II

    2016-03-01

    Experts are more proficient in manipulating and translating between multiple representations (MRs) of a given concept than novices. Studies have shown that instruction using MR can increase student understanding of MR, and one model for MR instruction in chemistry is the chemistry triplet proposed by Johnstone. Concreteness fading theory suggests that presenting concrete representations before abstract representations can increase the effectiveness of MR instruction; however, little work has been conducted on varying the order of different representations during instruction and the role of concreteness in assessment. In this study, we investigated the application of concreteness fading to MR instruction and assessment in teaching chemistry. In two experiments, undergraduate students in either introductory psychology courses or general chemistry courses were given MR instruction on phase changes using different orders of presentation and MR assessment questions based on the representations in the chemistry triplet. Our findings indicate that the order of presentation based on levels of concreteness in MR chemistry instruction is less important than implementation of comprehensive MR assessments. Even after MR instruction, students display an asymmetric understanding of the chemical phenomenon on the MR assessments. Greater emphasis on MR assessments may be an important component in MR instruction that effectively moves novices toward more expert MR understanding.

  3. Polyimides Derived from Novel Asymmetric Dianhydrides

    Science.gov (United States)

    Chuang, Chun-Hua (Inventor)

    2012-01-01

    This invention relates to the compositions and processes for preparing thermoset and thermoplastic polyimides derived from novel asymmetrical dianhydrides: specifically 2,3,3',4' benzophenone dianhydride (a-BTDA), and 3,4'-(hexafluoroisopropylidene)diphthalic anhydride (a-6FDA). The a-BTDA anhydride is prepared by Suzuki coupling with catalysts from a mixed anhydride of 3,4-dimethylbenzoic acid or 2,3-dimethylbenzoic acid with 2,3-dimethylphenylboronic acid or 3,4-dimethylphenylboronic acid respectively, to form 2,3,3',4'-tetramethylbenzophenone which is oxidized to form 2,3,3',4'-benzophenonetetracarboxylic acid followed by cyclodehydration to obtain a-BTDA. The a-6FDA is prepared by nucleophilic triflouoromethylation of 2,3,3',4'-tetramethylbenzophenone with trifluoromethyltrimethylsilane to form 3,4'-(trifluoromethylmethanol)-bis(o-xylene) which is converted to 3,4'-(hexafluoroisopropylidene-bis(o-xylene). The 3,4'-(hexafluoroisopropylidene)-bis(o-xylene) is oxidized to the corresponding tetraacid followed by cyclodehydration to yield a-6FDA.

  4. Review of a model to assess stranding of juvenile salmon by ship wakes along the Lower Columbia River, Oregon and Washington

    Science.gov (United States)

    Kock, Tobias J.; Plumb, John M.; Adams, Noah S.

    2013-01-01

    Long period wake waves from deep draft vessels have been shown to strand small fish, particularly juvenile Chinook salmon Oncorhynchus tschawytcha, in the lower Columbia River (LCR). The U.S. Army Corps of Engineers is responsible for maintaining the shipping channel in the LCR and recently conducted dredging operations to deepen the shipping channel from an authorized depth of 40 feet(ft) to an authorized depth of 43 ft (in areas where rapid shoaling was expected, dredging operations were used to increase the channel depth to 48 ft). A model was developed to estimate stranding probabilities for juvenile salmon under the 40- and 43-ft channel scenarios, to determine if channel deepening was going to affect wake stranding (Assessment of potential stranding of juvenile salmon by ship wakes along the Lower Columbia River under scenarios of ship traffic and channel depth: Report prepared for the Portland District U.S. Army Corps of Engineers, Portland, Oregon). The U.S. Army Corps of Engineers funded the U.S. Geological Survey to review this model. A total of 30 review questions were provided to guide the review process, and these questions are addressed in this report. In general, we determined that the analyses by Pearson (2011) were appropriate given the data available. We did identify two areas where additional information could have been provided: (1) a more thorough description of model diagnostics and model selection would have been useful for the reader to better understand the model framework; and (2) model uncertainty should have been explicitly described and reported in the document. Stranding probability estimates between the 40- and 43-ft channel depths were minimally different under most of the scenarios that were examined by Pearson (2011), and a discussion of the effects of uncertainty given these minimal differences would have been useful. Ultimately, however, a stochastic (or simulation) model would provide the best opportunity to illustrate

  5. Prospects for Improving the Critical Current Density of Superconducting Nb3Sn Strands via Optimization of Nb3Sn Fraction, Stoichiometry, and Grain Size

    Science.gov (United States)

    Xu, Xingchen

    determined by three factors: the fraction of current-carrying Nb3Sn phase in a subelement, the irreversibility field Birr which mainly depends on the Nb3Sn phase composition (i.e., Sn content), doping, and strain state, and the flux-line pinning characteristics (including the maximum pinning force Fp,max and the pinning force peak field) which mainly depend on grain size. Then these three factors will be addressed in three chapters. In chapter 3, the question "how to improve Nb 3Sn fraction in a subelement" is investigated. A model is developed to predict the phase fractions in reacted strands based on the starting amounts of precursors. In chapter 4, a model is developed to find out what essentially determines the composition of non-stoichiometric compounds formed by diffusion reactions. It can be used as a guide for controlling the Sn content of the Nb3Sn phase formed in Sn source/Nb3Sn/Nb diffusion reaction couples. Finally, chapter 5 demonstrates that the subelement structures can be carefully modified to enable the internal oxidation of Nb-Zr alloy, so that fine ZrO2 precipitates are formed in Nb3Sn; these ZrO2 particles can significantly refine Nb3Sn grain size and improve the high-field Jc.

  6. Asymmetric triplex metallohelices with high and selective activity against cancer cells

    Science.gov (United States)

    Faulkner, Alan D.; Kaner, Rebecca A.; Abdallah, Qasem M. A.; Clarkson, Guy; Fox, David J.; Gurnani, Pratik; Howson, Suzanne E.; Phillips, Roger M.; Roper, David I.; Simpson, Daniel H.; Scott, Peter

    2014-09-01

    Small cationic amphiphilic α-helical peptides are emerging as agents for the treatment of cancer and infection, but they are costly and display unfavourable pharmacokinetics. Helical coordination complexes may offer a three-dimensional scaffold for the synthesis of mimetic architectures. However, the high symmetry and modest functionality of current systems offer little scope to tailor the structure to interact with specific biomolecular targets, or to create libraries for phenotypic screens. Here, we report the highly stereoselective asymmetric self-assembly of very stable, functionalized metallohelices. Their anti-parallel head-to-head-to-tail ‘triplex’ strand arrangement creates an amphipathic functional topology akin to that of the active sub-units of, for example, host-defence peptides and p53. The metallohelices display high, structure-dependent toxicity to the human colon carcinoma cell-line HCT116 p53++, causing dramatic changes in the cell cycle without DNA damage. They have lower toxicity to human breast adenocarcinoma cells (MDA-MB-468) and, most remarkably, they show no significant toxicity to the bacteria methicillin-resistant Staphylococcus aureus and Escherichia coli.

  7. COSMOS: accurate detection of somatic structural variations through asymmetric comparison between tumor and normal samples.

    Science.gov (United States)

    Yamagata, Koichi; Yamanishi, Ayako; Kokubu, Chikara; Takeda, Junji; Sese, Jun

    2016-05-05

    An important challenge in cancer genomics is precise detection of structural variations (SVs) by high-throughput short-read sequencing, which is hampered by the high false discovery rates of existing analysis tools. Here, we propose an accurate SV detection method named COSMOS, which compares the statistics of the mapped read pairs in tumor samples with isogenic normal control samples in a distinct asymmetric manner. COSMOS also prioritizes the candidate SVs using strand-specific read-depth information. Performance tests on modeled tumor genomes revealed that COSMOS outperformed existing methods in terms of F-measure. We also applied COSMOS to an experimental mouse cell-based model, in which SVs were induced by genome engineering and gamma-ray irradiation, followed by polymerase chain reaction-based confirmation. The precision of COSMOS was 84.5%, while the next best existing method was 70.4%. Moreover, the sensitivity of COSMOS was the highest, indicating that COSMOS has great potential for cancer genome analysis.

  8. Asymmetric pore occupancy in crystal structure of OmpF porin from Salmonella typhi.

    Science.gov (United States)

    Balasubramaniam, D; Arockiasamy, Arulandu; Kumar, P D; Sharma, Amit; Krishnaswamy, S

    2012-06-01

    OmpF is a major general diffusion porin of Salmonella typhi, a Gram-negative bacterium, which is an obligatory human pathogen causing typhoid. The structure of S. typhi Ty21a OmpF (PDB Id: 3NSG) determined at 2.8 Å resolution by X-ray crystallography shows a 16-stranded β-barrel with three β-barrel monomers associated to form a trimer. The packing observed in S. typhi Ty21a rfOmpF crystals has not been observed earlier in other porin structures. The variations seen in the loop regions provide a starting point for using the S. typhi OmpF for structure-based multi-valent vaccine design. Along one side of the S. typhi Ty21a OmpF pore there exists a staircase arrangement of basic residues (20R, 60R, 62K, 65R, 77R, 130R and 16K), which also contribute, to the electrostatic potential in the pore. This structure suggests the presence of asymmetric electrostatics in the porin oligomer. Moreover, antibiotic translocation, permeability and reduced uptake in the case of mutants can be understood based on the structure paving the way for designing new antibiotics.

  9. Loss Aversion and the Asymmetric Transmission of Monetary Policy

    DEFF Research Database (Denmark)

    Santoro, Emiliano; Petrella, Ivan; Pfajfar, Damjan

    2014-01-01

    There is widespread evidence that monetary policy exerts asymmetric effects on output over contractions and expansions in economic activity, while price responses display no sizeable asymmetry. To rationalize these facts we develop a dynamic general equilibrium model where households’ utility...

  10. Magnetic Field and Force Calculations for ATLAS Asymmetrical Structure

    CERN Document Server

    Nessi, Marzio

    2001-01-01

    Magnetic field distortion in the assymetrical ATLAS structure are calculated. Magnetic forces in the system are estimated. 3D magnetic field simulation by the Opera3D code for symmetrical and asymmetrical systems is used.

  11. Asymmetric H-D exchange reactions of fluorinated aromatic ketones

    KAUST Repository

    Zhao, Yujun

    2012-01-01

    Chiral bicyclic guanidine catalyzes the asymmetric H-D exchange reactions. Up to 30% ee was achieved. DFT calculations were employed to elucidate and explain the origin of the reaction\\'s stereoselectivity. © 2012 The Royal Society of Chemistry.

  12. Asymmetric Intramolecular Cyclopropanation Induced by (β-Diketone)-copper Complex

    Institute of Scientific and Technical Information of China (English)

    Qing Fang CHENG; Xing You XU; Wei Xing MA; Tian Pa YOU

    2005-01-01

    Asymmetric intramolecular cyclopropanation of allylic diazoacetate was investigated using a chiral (β-diketone)-copper complex as catalyst, excellent yield and enantioselectivity were achieved. Some factors influencing enantioselectivity were discussed.

  13. 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...

  14. Asymmetric Dark Matter in the shear-dominated universe

    Science.gov (United States)

    Iminniyaz, Hoernisa

    2017-02-01

    We explore the relic abundance of asymmetric Dark Matter in shear-dominated universe in which it is assumed the universe is expanded anisotropically. The modified expansion rate leaves its imprint on the relic density of asymmetric Dark Matter particles if the asymmetric Dark Matter particles are decoupled in shear dominated era. We found the relic abundances for particle and anti-particle are increased. The particle and anti-particle abundances are almost in the same amount for the larger value of the shear factor xe which makes the indirect detection possible for asymmetric Dark Matter. We use the present day Dark Matter density from the observation to find the constraints on the parameter space in this model.

  15. Asymmetric periflexural exanthema: A report in an adult patient

    Directory of Open Access Journals (Sweden)

    Zawar V

    2003-11-01

    Full Text Available Asymmetric periflexural exanthem (APE is a distinctive exanthem, probably viral in origin. It is largely a disease of childhood and is uncommon in adults. We report an adult man presenting with the typical clinical findings of APE.

  16. 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.

  17. Abundance of Asymmetric Dark Matter in Brane World Cosmology

    Science.gov (United States)

    Abdusattar, Haximjan; Iminniyaz, Hoernisa

    2016-09-01

    Relic abundance of asymmetric Dark Matter particles in brane world cosmological scenario is investigated in this article. Hubble expansion rate is enhanced in brane world cosmology and it affects the relic abundance of asymmetric Dark Matter particles. We analyze how the relic abundance of asymmetric Dark Matter is changed in this model. We show that in such kind of nonstandard cosmological scenario, indirect detection of asymmetric Dark Matter is possible if the cross section is small enough which let the anti-particle abundance kept in the same amount with the particle. We show the indirect detection signal constraints can be used to such model only when the cross section and the 5-dimensional Planck mass scale are in appropriate values. Supported by the National Natural Science Foundation of China under Grant No. 11365022

  18. Asymptotic Theory for Extended Asymmetric Multivariate GARCH Processes

    NARCIS (Netherlands)

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

    2016-01-01

    textabstractThe paper considers various extended asymmetric multivariate conditional volatility models, and derives appropriate regularity conditions and associated asymptotic theory. This enables checking of internal consistency and allows valid statistical inferences to be drawn based on empirical

  19. 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.

  20. Asymmetric dynamic phase holographic grating in nematic liquid crystal

    Science.gov (United States)

    Ren, Chang-Yu; Shi, Hong-Xin; Ai, Yan-Bao; Yin, Xiang-Bao; Wang, Feng; Ding, Hong-Wei

    2016-09-01

    A new scheme for recording a dynamic phase grating with an asymmetric profile in C60-doped homeotropically aligned nematic liquid crystal (NLC) was presented. An oblique incidence beam was used to record the thin asymmetric dynamic phase holographic grating. The diffraction efficiency we achieved is more than 40%, exceeding the theoretical limit for symmetric profile gratings. Both facts can be explained by assuming that a grating with an asymmetric saw-tooth profile is formed in the NLC. Finally, physical mechanism and mathematical model for characterizing the asymmetric phase holographic grating were presented, based on the photo-refractive-like (PR-like) effect. Project supported by the Science and Technology Programs of the Educational Committee of Heilongjiang Province, China (Grant No. 12541730) and the National Natural Science Foundation of China (Grant No. 61405057).

  1. Results of investigations into coal cutting by asymmetric disks

    Energy Technology Data Exchange (ETDEWEB)

    Krauze, K.

    1985-02-01

    Effects are analyzed of design and specifications of asymmetric disk cutters on coal cutting by a shearer loader with disk cutters on helical cutting drums. Effects of disk diameter, wedge angle, cutting depth and chip thickness on cutting resistance were analyzed under operational conditions (a coal seam was cut by asymmetric disk cutters). On the basis of analysis of coal resistance to cutting by asymmetric cutting disks, regression equations were derived which describe coal cutting. Effects of disk parameters and cutting conditions on cutting resistance were determined. Analyses show that replacing radial cutting tools with asymmetric disk cutters would cause an increase in energy consumption of cutting and increase coal resistance to cutting. 1 reference.

  2. Radiation Induced DNA Double Strand Break Studies of a Metal Sensitive Novel Bacterial Isolate from East Calcutta Wetland

    Directory of Open Access Journals (Sweden)

    Sanhita Chowdhury

    2009-01-01

    Full Text Available Problem statement: This study was an attempt to isolate anaerobic microbes with potential for DNA double strand break repair using methanogen specific medium (DSMZ 120 from East Calcutta Wetland in India. It also intended to verify the specificity of the medium for isolation of the desired family of microbe. Approach: Culture based technique was used to obtain the pure isolate that was further characterized in details. For double strand break repair studies, isolate was irradiated with different doses of 60Co gamma rays and its subsequent repair was observed using pulse field gel electrophoresis and asymmetric field inversion gel electrophoresis. Inhibitor was used to predict the mechanism of repair. Results: In this study we isolated and characterized a metal sensitive anaerobic microbial strain obtained using methanogen specific medium (DSMZ 120 from East Calcutta Wetland in India. The strain was one of the members of the group of uncultivated bacterium as evident from phylogenetic analysis, thus indicating the successful cultivation of an as yet uncultivable novel microbe (GenBank Acc. No. FJ 930097 and also the non-specific growth of microbes in prescribed medium. It was a Gram positive Bacilli, member of Fermicutes with optimum growth at 25°C and pH-7. The growth curve analysis showed a lag phase up to 24 h, log phase from 24-48 h, an early stationary phase from 96 h onwards. The strain could repair the DNA double strand break caused by irradiation with 60Co γ rays. The dose profile study revealed maximum repair at 60 Grays and thereafter a drop in repair ability with increase in irradiation dose. The time required for repair showed an essential incubation period of 4 h. The DNA polymerase inhibitor, Arabinose CTP inhibited the repair indicating the involvement of polymerase in the repair process and thus pointing towards homologous recombination as the underlying mechanism. Conclusion: In this study we were able to cultivate an as yet

  3. Research on the Design and Modification of Asymmetric Spur Gear

    OpenAIRE

    Xiaohe Deng; Lin Hua; Xinghui Han

    2015-01-01

    A design method for the geometric shape and modification of asymmetric spur gear was proposed, in which the geometric shape and modification of the gear can be obtained directly according to the rack-cutter profile. In the geometric design process of the gear, a rack-cutter with different pressure angles and fillet radius in the driving side and coast side was selected, and the generated asymmetric spur gear profiles also had different pressure angles and fillets accordingly. In the modificat...

  4. Catalytic Methods in Asymmetric Synthesis Advanced Materials, Techniques, and Applications

    CERN Document Server

    Gruttadauria, Michelangelo

    2011-01-01

    This book covers advances in the methods of catalytic asymmetric synthesis and their applications. Coverage moves from new materials and technologies to homogeneous metal-free catalysts and homogeneous metal catalysts. The applications of several methodologies for the synthesis of biologically active molecules are discussed. Part I addresses recent advances in new materials and technologies such as supported catalysts, supports, self-supported catalysts, chiral ionic liquids, supercritical fluids, flow reactors and microwaves related to asymmetric catalysis. Part II covers advances and milesto

  5. Cooperative Mechanism of Supply Chain Under Asymmetric Information

    Institute of Scientific and Technical Information of China (English)

    郭敏; 王红卫; 瞿坦

    2003-01-01

    The cooperative mechanism is one main issue in the decentralized supply chain system, especially in an asymmetric information structure. We analyze the non-cooperative game behavior of a 2-echelon distribution supply chain, compare the results with the system optimal solution, and give the supplier dominated cooperative mechanisms. We also analyze the validity of our contract under the asymmetric retailers' holding cost information and give some useful conclusions.

  6. Asymmetric zygote division: A mystery starting point of embryogenesis.

    Science.gov (United States)

    Zhao, Jing; Sun, Meng-Xiang

    2016-10-02

    In angiosperm, asymmetric zygote division is critical for embryogenesis. The molecular mechanism underlying this process has gained a great attention recently. Some players involve in the control of both accurate position and correct orientation of zygote division plane have been found, which provide useful clues for the extensive investigations. It is getting clear that both internal and external factors are involved in this complex regulatory mechanism and the asymmetric zygote division seems with great impact in cell fate determination and embryo pattern formation.

  7. Reduction of contact stresses using involute gears with asymmetric teeth

    OpenAIRE

    2015-01-01

    Asymmetrical involute gears have a different value of the operating pressure angle for right and left side of the gear. These teeth are suitable for one direction of rotation. Such teeth enable to change the length of the generating line. They enable to improve the value of reduced radii of curvature. Asymmetrical teeth allow reducing the values of Hertz's pressures, especially on the root of the teeth. Hertz pressures are directly related to the asymmetry.

  8. The Asymmetric Impact of Growth Fluctuation on Human Development

    OpenAIRE

    Serap Bedir

    2015-01-01

    In this paper, we re-examine the impact of economic growth fluctuation on human development indicators. Using the per capita growth rate and human development indicators for 131 countries between 1974 and 2007, we find that growth acceleration and deceleration have significant impact on the human development indicators. We also find that the effects are asymmetric. This asymmetric effect is valid both in terms of acceleration and deceleration periods and countries which are classified accordi...

  9. Heavy Metal Exposure Influences Double Strand Break DNA Repair Outcomes.

    Directory of Open Access Journals (Sweden)

    Maria E Morales

    Full Text Available Heavy metals such as cadmium, arsenic and nickel are classified as carcinogens. Although the precise mechanism of carcinogenesis is undefined, heavy metal exposure can contribute to genetic damage by inducing double strand breaks (DSBs as well as inhibiting critical proteins from different DNA repair pathways. Here we take advantage of two previously published culture assay systems developed to address mechanistic aspects of DNA repair to evaluate the effects of heavy metal exposures on competing DNA repair outcomes. Our results demonstrate that exposure to heavy metals significantly alters how cells repair double strand breaks. The effects observed are both specific to the particular metal and dose dependent. Low doses of NiCl2 favored resolution of DSBs through homologous recombination (HR and single strand annealing (SSA, which were inhibited by higher NiCl2 doses. In contrast, cells exposed to arsenic trioxide preferentially repaired using the "error prone" non-homologous end joining (alt-NHEJ while inhibiting repair by HR. In addition, we determined that low doses of nickel and cadmium contributed to an increase in mutagenic recombination-mediated by Alu elements, the most numerous family of repetitive elements in humans. Sequence verification confirmed that the majority of the genetic deletions were the result of Alu-mediated non-allelic recombination events that predominantly arose from repair by SSA. All heavy metals showed a shift in the outcomes of alt-NHEJ repair with a significant increase of non-templated sequence insertions at the DSB repair site. Our data suggest that exposure to heavy metals will alter the choice of DNA repair pathway changing the genetic outcome of DSBs repair.

  10. Reachability bounds for chemical reaction networks and strand displacement systems.

    Science.gov (United States)

    Condon, Anne; Kirkpatrick, Bonnie; Maňuch, Ján

    2014-01-01

    Chemical reaction networks (CRNs) and DNA strand displacement systems (DSDs) are widely-studied and useful models of molecular programming. However, in order for some DSDs in the literature to behave in an expected manner, the initial number of copies of some reagents is required to be fixed. In this paper we show that, when multiple copies of all initial molecules are present, general types of CRNs and DSDs fail to work correctly if the length of the shortest sequence of reactions needed to produce any given molecule exceeds a threshold that grows polynomially with attributes of the system.

  11. Asymmetric neuroimaging in Creutzfeldt-Jakob disease: a ruse.

    Science.gov (United States)

    Bavis, James; Reynolds, Patrick; Tegeler, Charles; Clark, Paige

    2003-10-01

    Creutzfeldt-Jakob disease (CJD) causes diffuse neurological symptoms, but asymmetric lesions have been found on conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI). Less often, position emission tomography (PET) scanning can also reveal asymmetric lesions in patients with CJD. Such imaging may mislead clinicians. The authors present a case of a woman with CJD who was diagnosed as having suffered a stroke because she had asymmetric T2-weighted imaging (T2WI) MRI abnormalities that were interpreted as a stroke. It was noted that the patient had clinical features consistent with CJD, including rapidly progressive dementia, myoclonus, cerebellar dysfunction, and pyramidal and extrapyramidal signs. This diagnosis was supported by periodic epileptiform discharges on the electroencephalogram (EEG) and by elevated 14-3-3 protein in the cerebrospinal fluid. MRI T2WI and DWI showed dramatically asymmetric abnormalities involving the left cortex. A PET study found decreased metabolism in the left cerebral and right cerebellar hemispheres. The patient's clinical, EEG, and laboratory data were all consistent with CJD, not other diseases, but the MRI and PET had atypical, asymmetric findings. This case demonstrates that CJD should be considered in the differential diagnosis of patients with rapidly progressive neurological decline, even if they have asymmetric imaging findings.

  12. Asymmetric nucleosomes flank promoters in the budding yeast genome.

    Science.gov (United States)

    Ramachandran, Srinivas; Zentner, Gabriel E; Henikoff, Steven

    2015-03-01

    Nucleosomes in active chromatin are dynamic, but whether they have distinct structural conformations is unknown. To identify nucleosomes with alternative structures genome-wide, we used H4S47C-anchored cleavage mapping, which revealed that 5% of budding yeast (Saccharomyces cerevisiae) nucleosome positions have asymmetric histone-DNA interactions. These asymmetric interactions are enriched at nucleosome positions that flank promoters. Micrococcal nuclease (MNase) sequence-based profiles of asymmetric nucleosome positions revealed a corresponding asymmetry in MNase protection near the dyad axis, suggesting that the loss of DNA contacts around H4S47 is accompanied by protection of the DNA from MNase. Chromatin immunoprecipitation mapping of selected nucleosome remodelers indicated that asymmetric nucleosomes are bound by the RSC chromatin remodeling complex, which is required for maintaining nucleosomes at asymmetric positions. These results imply that the asymmetric nucleosome-RSC complex is a metastable intermediate representing partial unwrapping and protection of nucleosomal DNA on one side of the dyad axis during chromatin remodeling.

  13. 75 FR 38977 - Pre-Stressed Concrete Steel Wire Strand from the People's Republic of China: Notice of Amended...

    Science.gov (United States)

    2010-07-07

    ... International Trade Administration Pre-Stressed Concrete Steel Wire Strand from the People's Republic of China... concrete steel wire strand (PC strand) from the People's Republic of China (PRC). On June 22, 2010, the ITC...-Stressed Concrete Steel Wire Strand from the People's Republic of China, USITC Pub. 4162, Inv. Nos....

  14. Mechanical behaviors of multi-filament twist superconducting strand under tensile and cyclic loading

    Science.gov (United States)

    Wang, Xu; Li, Yingxu; Gao, Yuanwen

    2016-01-01

    The superconducting strand, serving as the basic unit cell of the cable-in-conduit-conductors (CICCs), is a typical multi-filament twist composite which is always subjected to a cyclic loading under the operating condition. Meanwhile, the superconducting material Nb3Sn in the strand is sensitive to strain frequently relating to the performance degradation of the superconductivity. Therefore, a comprehensive study on the mechanical behavior of the strand helps understanding the superconducting performance of the strained Nb3Sn strands. To address this issue, taking the LMI (internal tin) strand as an example, a three-dimensional structural finite element model, named as the Multi-filament twist model, of the strand with the real configuration of the LMI strand is built to study the influences of the plasticity of the component materials, the twist of the filament bundle, the initial thermal residual stress and the breakage and its evolution of the filaments on the mechanical behaviors of the strand. The effective properties of superconducting filament bundle with random filament breakage and its evolution versus strain are obtained based on the damage theory of fiber-reinforced composite materials proposed by Curtin and Zhou. From the calculation results of this model, we find that the occurrence of the hysteresis loop in the cyclic loading curve is determined by the reverse yielding of the elastic-plastic materials in the strand. Both the initial thermal residual stress in the strand and the pitch length of the filaments have significant impacts on the axial and hysteretic behaviors of the strand. The damage of the filaments also affects the axial mechanical behavior of the strand remarkably at large axial strain. The critical current of the strand is calculated by the scaling law with the results of the Multi-filament twist model. The predicted results of the Multi-filament twist model show an acceptable agreement with the experiment.

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

    Science.gov (United States)

    Gross, Joshua B; Gangidine, Andrew; Powers, Amanda K

    2016-11-01

    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.

  16. 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.

  17. Hemispherical anomaly from asymmetric initial states

    Science.gov (United States)

    Ashoorioon, Amjad; Koivisto, Tomi

    2016-08-01

    We investigate if the hemispherical asymmetry in the CMB is produced from "asymmetric" excited initial conditions. We show that in the limit where the deviations from the Bunch-Davies vacuum are large and the scale of new physics is maximally separated from the inflationary Hubble parameter, the primordial power spectrum is modulated only by position-dependent dipole and quadrupole terms. Requiring the dipole contribution in the power spectrum to account for the observed power asymmetry, A =0.07 ±0.022 , we show that the amount of quadrupole terms is roughly equal to A2. The mean local bispectrum, which gets enhanced for the excited initial state, is within the 1 σ bound of Planck 2015 results for a large field model, fNL≃4.17 , but is reachable by future CMB experiments. The amplitude of the local non-Gaussianity modulates around this mean value, depending on the angle that the correlated patches on the 2d CMB surface make with the preferred direction. The amount of variation is minimized for the configuration in which the short and long wavelength modes are around the preferred pole and |k→3|≈|k→l ≈10|≪|k→1|≈|k→2|≈|k→l ≈2500| with fNLmin≈3.64 . The maximum occurs when these modes are at the antipode of the preferred pole, fNLmax≈4.81 . The difference of non-Gaussianity between these two configurations is as large as ≃1.17 , which can be used to distinguish this scenario from other scenarios that try to explain the observed hemispherical asymmetry.

  18. Asymmetric transfer of auditory perceptual learning

    Directory of Open Access Journals (Sweden)

    Sygal eAmitay

    2012-11-01

    Full Text Available Perceptual skills can improve dramatically even with minimal practice. A major and practical benefit of learning, however, is in transferring the improvement on the trained task to untrained tasks or stimuli, yet the mechanisms underlying this process are still poorly understood. Reduction of internal noise has been proposed as a mechanism of perceptual learning, and while we have evidence that frequency discrimination (FD learning is due to a reduction of internal noise, the source of that noise was not determined. In this study, we examined whether reducing the noise associated with neural phase locking to tones can explain the observed improvement in behavioural thresholds. We compared FD training between two tone durations (15 and 100 ms that straddled the temporal integration window of auditory nerve fibers upon which computational modeling of phase locking noise was based. Training on short tones resulted in improved FD on probe tests of both the long and short tones. Training on long tones resulted in improvement only on the long tones. Simulations of FD learning, based on the computational model and on signal detection theory, were compared with the behavioral FD data. We found that improved fidelity of phase locking accurately predicted transfer of learning from short to long tones, but also predicted transfer from long to short tones. The observed lack of transfer from long to short tones suggests the involvement of a second mechanism. Training may have increased the temporal integration window which could not transfer because integration time for the short tone is limited by its duration. Current learning models assume complex relationships between neural populations that represent the trained stimuli. In contrast, we propose that training-induced enhancement of the signal-to-noise ratio offers a parsimonious explanation of learning and transfer that easily accounts for asymmetric transfer of learning.

  19. Asymmetric inhibitory treatment effects in multilingual aphasia.

    Science.gov (United States)

    Goral, Mira; Naghibolhosseini, Maryam; Conner, Peggy S

    2013-01-01

    Findings from recent psycholinguistic studies of bilingual processing support the hypothesis that both languages of a bilingual are always active and that bilinguals continually engage in processes of language selection. This view aligns with the convergence hypothesis of bilingual language representation. Furthermore, it is hypothesized that when bilinguals perform a task in one language they need to inhibit their other, nontarget language(s) and that stronger inhibition is required when the task is performed in the weaker language than in the stronger one. The study of multilingual individuals who acquire aphasia resulting from a focal brain lesion offers a unique opportunity to test the convergence hypothesis and the inhibition asymmetry. We report on a trilingual person with chronic nonfluent aphasia who at the time of testing demonstrated greater impairment in her first acquired language (Persian) than in her third, later learned language (English). She received treatment in English followed by treatment in Persian. An examination of her connected language production revealed improvement in her grammatical skills in each language following intervention in that language, but decreased grammatical accuracy in English following treatment in Persian. The increased error rate was evident in structures that are used differently in the two languages (e.g., auxiliary verbs). The results support the prediction that greater inhibition is applied to the stronger language than to the weaker language, regardless of their age of acquisition. We interpret the findings as consistent with convergence theories that posit overlapping neuronal representation and simultaneous activation of multiple languages and with proficiency-dependent asymmetric inhibition in multilinguals.

  20. Chilly dark sectors and asymmetric reheating

    Science.gov (United States)

    Adshead, Peter; Cui, Yanou; Shelton, Jessie

    2016-06-01

    In a broad class of theories, the relic abundance of dark matter is determined by interactions internal to a thermalized dark sector, with no direct involvement of the Standard Model (SM). We point out that these theories raise an immediate cosmological question: how was the dark sector initially populated in the early universe? Motivated in part by the difficulty of accommodating large amounts of entropy carried in dark radiation with cosmic microwave background measurements of the effective number of relativistic species at recombination, N eff , we aim to establish which admissible cosmological histories can populate a thermal dark sector that never reaches thermal equilibrium with the SM. The minimal cosmological origin for such a dark sector is asymmetric reheating, when the same mechanism that populates the SM in the early universe also populates the dark sector at a lower temperature. Here we demonstrate that the resulting inevitable inflaton-mediated scattering between the dark sector and the SM can wash out a would-be temperature asymmetry, and establish the regions of parameter space where temperature asymmetries can be generated in minimal reheating scenarios. Thus obtaining a temperature asymmetry of a given size either restricts possible inflaton masses and couplings or necessitates a non-minimal cosmology for one or both sectors. As a side benefit, we develop techniques for evaluating collision terms in the relativistic Boltzmann equation when the full dependence on Bose-Einstein or Fermi-Dirac phase space distributions must be retained, and present several new results on relativistic thermal averages in an appendix.

  1. Applications of asymmetric nanotextured parylene surface using its wetting and transport properties

    Science.gov (United States)

    Sekeroglu, Koray

    In this thesis, basic digital fluidics devices were introduced using polymeric nanorods (nano-PPX) inspired from nature. Natural inspiration ignited this research by observing butterfly wings, water strider legs, rye grass leaves, and their asymmetric functions. Nano-PPX rods, manufactured by an oblique angle polymerization (OAP) method, are asymmetrically aligned structures that have unidirectional wetting properties. Nano-PPX demonstrates similar functions to the directional textured surfaces of animals and plants in terms of wetting, adhesion, and transport. The water pin-release mechanism on the asymmetric nano-PPX surface with adhesion function provides a great transport property. How the asymmetry causes transport is discussed in terms of hysteresis and interface contact of water droplets. In this study, the transport property of nano-PPX rods is used to guide droplets as well as transporting cargo such as microgels. With the addition of tracks on the nano-PPX rods, the surfaces were transformed into basic digital fluidics devices. The track-assisted nano-PPX has been employed to applications (i.e. sorting, mixing, and carrying cargo particles). Thus, digital fluidics devices fabricated on nano-PPX surface is a promising pathway to assemble microgels in the field of bioengineering. The characterization of the nano textured surface was completed using methods such as Scanning Electron Microscopy, Atomic Force Microscopy, Contact Angle Goniometry, and Fourier Transform Infra-Red Spectroscopy. These methods helped to understand the physical and chemical properties of nano-PPX. Parameters such as advancing and receding contact angles, nanorod tilt angle, and critical drop volumes were utilized to investigate the anisotropic wetting properties of nano-PPX surface. This investigation explained the directional wetting behavior of the surface as well as approaching new design parameters for adjusting surface properties. The nanorod tilt angle was a key parameter

  2. Impact and Use of the Asymmetric Property in Bi-directional Cooperative Relaying under Asymmetric Traffic Conditions

    Science.gov (United States)

    Saeki, Takaaki; Yamamoto, Koji; Murata, Hidekazu; Yoshida, Susumu

    Cooperative relaying (CR) is a promising technique to provide spatial diversity by combining multiple signals from source and relay stations. In the present paper, the impact and use of the asymmetric property in bi-directional CR under asymmetric traffic conditions are discussed assuming that CR involves one communication pair and one relay station in a time division duplex (TDD) system. The asymmetric property means that the average communication quality differs for each transmission direction because of the difference in signal power between the combined signals for each direction. First, numerical results show the asymmetric property of bi-directional CR. Next, in order to evaluate the impact of the asymmetric property, the optimal relay position and resource allocation are compared to those in simple multi-hop relaying, which does not have the asymmetric property. Numerical results show that, in order to maximize the overall quality of bi-directional communication, the optimal relay position in CR depends on the offered traffic ratio, which is defined as the traffic ratio of each transmission direction, while the offered traffic ratio does not affect the optimal relay position in multi-hop relaying. Finally, the asymmetric property is used to enhance the overall quality. Specifically, a high overall quality can be achieved by, for example, opportunistically switching to the transmission direction with higher quality. Under asymmetric traffic conditions, weighted proportionally fair scheduling (WPFS), which is proposed in the context of downlink scheduling in a cellular network, is applied to transmission direction switching. Numerical results reveal that WPFS provides a high overall quality and that the quality ratio is similar to the offered traffic ratio.

  3. Mapping meiotic single-strand DNA reveals a new landscape of DNA double-strand breaks in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Cyril Buhler

    2007-12-01

    Full Text Available DNA double-strand breaks (DSBs, which are formed by the Spo11 protein, initiate meiotic recombination. Previous DSB-mapping studies have used rad50S or sae2Delta mutants, which are defective in break processing, to accumulate Spo11-linked DSBs, and report large (> or = 50 kb "DSB-hot" regions that are separated by "DSB-cold" domains of similar size. Substantial recombination occurs in some DSB-cold regions, suggesting that DSB patterns are not normal in rad50S or sae2Delta mutants. We therefore developed a novel method to map genome-wide, single-strand DNA (ssDNA-associated DSBs that accumulate in processing-capable, repair-defective dmc1Delta and dmc1Delta rad51Delta mutants. DSBs were observed at known hot spots, but also in most previously identified "DSB-cold" regions, including near centromeres and telomeres. Although approximately 40% of the genome is DSB-cold in rad50S mutants, analysis of meiotic ssDNA from dmc1Delta shows that most of these regions have substantial DSB activity. Southern blot assays of DSBs in selected regions in dmc1Delta, rad50S, and wild-type cells confirm these findings. Thus, DSBs are distributed much more uniformly than was previously believed. Comparisons of DSB signals in dmc1, dmc1 rad51, and dmc1 spo11 mutant strains identify Dmc1 as a critical strand-exchange activity genome-wide, and confirm previous conclusions that Spo11-induced lesions initiate all meiotic recombination.

  4. CRISPR-Cas9-guided Genome Engineering in C. elegans

    Science.gov (United States)

    Kim, Hyun-Min; Colaiácovo, Monica P.

    2016-01-01

    The CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) system is successfully being used for efficient and targeted genome editing in various organisms including the nematode C. elegans. Recent studies developed various CRISPR-Cas9 approaches to enhance genome engineering via two major DNA double-strand break repair pathways: non-homologous end joining and homologous recombination. Here we describe a protocol for Cas9-mediated C. elegans genome editing together with single guide RNA (sgRNA) and repair template cloning and injection methods required for delivering Cas9, sgRNAs and repair template DNA into the C. elegans germline. PMID:27366893

  5. Relativistic Guiding Center Equations

    Energy Technology Data Exchange (ETDEWEB)

    White, R. B. [PPPL; Gobbin, M. [Euratom-ENEA Association

    2014-10-01

    In toroidal fusion devices it is relatively easy that electrons achieve relativistic velocities, so to simulate runaway electrons and other high energy phenomena a nonrelativistic guiding center formalism is not sufficient. Relativistic guiding center equations including flute mode time dependent field perturbations are derived. The same variables as used in a previous nonrelativistic guiding center code are adopted, so that a straightforward modifications of those equations can produce a relativistic version.

  6. Joomla! 3 beginner's guide

    CERN Document Server

    Tiggeler, Eric

    2014-01-01

    An easy to use, step-by-step guide to creating professional, mobile-friendly websites with the free Joomla CMS. The Joomla! 3 Beginner's Guide Second Edition is the ultimate guide for web developers who wish to build upon their skills and knowledge on creating websites. Even if you're new to this subject, you won't have any difficulty understanding the clear and friendly instructions and explanations. No prior knowledge of HTML and CSS is required.

  7. Sensor Characteristics Reference Guide

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-04-01

    The purpose of the guide is to inform building owners and operators of the current status, capabilities, and limitations of sensor technologies. It is hoped that this guide will aid in the design and procurement process and result in successful implementation of building sensor and control systems. DOE will also use this guide to identify research priorities, develop future specifications for potential market adoption, and provide market clarity through unbiased information.

  8. CISSP study guide

    CERN Document Server

    Conrad, Eric; Feldman, Joshua; Riggins, Kevin

    2011-01-01

    "The Eleventh Hour CISSP Study Guide" is keyed to the latest CISSP exam. This book is streamlined to include only core certification information and is presented for ease of last-minute studying. Main objectives of the exam are covered concisely with key concepts highlighted. This is the only guide you need for last-minute studying. This title answers the toughest questions and highlights core topics. This title can be paired with any other study guide so you are completely prepared.

  9. XML Style Guide

    Science.gov (United States)

    2015-07-01

    TELEMETRY GROUP DOCUMENT 125-15 XML STYLE GUIDE DISTRIBUTION A: APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED...OMB control number. 1. REPORT DATE 01 JUL 2015 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE XML Style Guide 5a. CONTRACT...standard was prepared by the Data Multiplex Committee of the Telemetry Group, Range Commanders Council. The XML Style Guide defines rules and guidelines

  10. Protection of DNA strand breakage by radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ho; Kim, In Gyu; Lee, Kang Suk; Kim, Kug Chan; Shim, Hae Won

    1997-12-01

    Human ceruloplasmin, the plasma copper containing protein, is thought to play an essential role in iron metabolism, but it also has antioxidant properties. Ceruloplasmin directly scavenged hydroxyl radicals (.OH) generated in dithiothreitol/FeCl{sub 3} system besides inhibitory function of hydroxyl radical formation and lipid peroxidation. Polyamines, spermidine and spermine, significantly protected the supercoiled DNA strand breakage by hydroxyl radicals and DNA strand breakage by UV was highly protected by all four polyamines used in this study. In polyamine deficient mutant KL527. It was shown that cell survivability following UV irradiation was slightly increased by exogenous polyamines putrescine and spermidine supplement. However the cell survivability of wild type (MG 1655) was not influenced by polyamine supplement. In {gamma}-irradiated cells, cell survivability of polyamine-deficient mutant strain KL527 was significantly increased by exogenous putrescine supplement and that of wild type strain MG1655 was similar irrespective of polyamine supplement. These results implicate the possibility that polyamines play a potent role in radioprotection of cell and DNA level. (author). 32 refs., 8 figs

  11. Genome-wide mapping of DNA strand breaks.

    Directory of Open Access Journals (Sweden)

    Frédéric Leduc

    Full Text Available Determination of cellular DNA damage has so far been limited to global assessment of genome integrity whereas nucleotide-level mapping has been restricted to specific loci by the use of specific primers. Therefore, only limited DNA sequences can be studied and novel regions of genomic instability can hardly be discovered. Using a well-characterized yeast model, we describe a straightforward strategy to map genome-wide DNA strand breaks without compromising nucleotide-level resolution. This technique, termed "damaged DNA immunoprecipitation" (dDIP, uses immunoprecipitation and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin end-labeling (TUNEL to capture DNA at break sites. When used in combination with microarray or next-generation sequencing technologies, dDIP will allow researchers to map genome-wide DNA strand breaks as well as other types of DNA damage and to establish a clear profiling of altered genes and/or intergenic sequences in various experimental conditions. This mapping technique could find several applications for instance in the study of aging, genotoxic drug screening, cancer, meiosis, radiation and oxidative DNA damage.

  12. Disseminated mycobacteriosis in a stranded loggerhead sea turtle (Caretta caretta).

    Science.gov (United States)

    Nardini, Giordano; Florio, Daniela; Di Girolamo, Nicola; Gustinelli, Andrea; Quaglio, Francesco; Fiorentini, Laura; Leopardi, Stefania; Fioravanti, Maria Letizia

    2014-06-01

    A loggerhead sea turtle (Caretta caretta) was found stranded alive along the Adriatic coast close to Ancona, Italy, displaying obtundation, tachypnea, and increased respiratory effort. It died a few hours after admission, and a postmortem examination was immediately performed. Miliary yellowish nodules were evident in the liver, and a lower number in the heart, stomach, and gut wall. Hundreds of whitish nodules were scattered in the lungs, with the majority of the pulmonary parenchyma being replaced by the lesions. Histologically, all nodular lesions consisted of a small central area of necrosis with acid-fast bacilli surrounded by epithelioid cells, macrophages, and lymphocytes. Giant cells were found in the spleen and the liver. Kidneys, lungs, liver, spleen, brain, and skin lesions were inoculated aseptically onto general isolation media and selective isolation media for mycobacteria. The isolate showed a restriction pattern identical to Mycobacterium chelonae by polymerase chain reaction-restriction fragment length polymorphism. To the best of the authors' knowledge, this is the first description of a disseminated infection caused by a potentially pathogenic mycobacteria in a stranded, free-ranging loggerhead sea turtle. Veterinary staff and biologists who handle sea turtles with suspected mycobacterial disease should protect themselves appropriately.

  13. An effective mesoscopic model of double-stranded DNA.

    Science.gov (United States)

    Jeon, Jae-Hyung; Sung, Wokyung

    2014-01-01

    Watson and Crick's epochal presentation of the double helix structure in 1953 has paved the way to intense exploration of DNA's vital functions in cells. Also, recent advances of single molecule techniques have made it possible to probe structures and mechanics of constrained DNA at length scales ranging from nanometers to microns. There have been a number of atomistic scale quantum chemical calculations or molecular level simulations, but they are too computationally demanding or analytically unfeasible to describe the DNA conformation and mechanics at mesoscopic levels. At micron scales, on the other hand, the wormlike chain model has been very instrumental in describing analytically the DNA mechanics but lacks certain molecular details that are essential in describing the hybridization, nano-scale confinement, and local denaturation. To fill this fundamental gap, we present a workable and predictive mesoscopic model of double-stranded DNA where the nucleotides beads constitute the basic degrees of freedom. With the inter-strand stacking given by an interaction between diagonally opposed monomers, the model explains with analytical simplicity the helix formation and produces a generalized wormlike chain model with the concomitant large bending modulus given in terms of the helical structure and stiffness. It also explains how the helical conformation undergoes overstretch transition to the ladder-like conformation at a force plateau, in agreement with the experiment.

  14. Charge Migration in DNA: A Double Stranded Model

    Institute of Scientific and Technical Information of China (English)

    BAO, Han; LU, Jing; FAN, Kang-Nian

    2006-01-01

    In particular, charge migration phenomena in DNA have attracted much interest because of relevance to the generation of damage and mutations which play important roles in most of life processes. In this paper a theory method was presented in which the DNA chain was treated as a double-stranded system, and the charge migration in DNA based on the donor-bridge-acceptor system was investigated by this model. After having obtained the Hamiltonian, the effects of the surrounding were explained and calculated. The double-strand calculation could lead to good exponential decay curves and this time two different falloff parameters were found respectively before and after 3 or 4 AT base pair bridge lengths as prediction. Lately theoretical study showed this result by addition of more parameter, and sequence effect was then concentrated on. The difference of transfer integral caused the different decay rate of unlike sequences, but bridge length was still proved to be the main factor on the decay rates.

  15. The RNA synthesis machinery of negative-stranded RNA viruses

    Energy Technology Data Exchange (ETDEWEB)

    Ortín, Juan, E-mail: jortin@cnb.csic.es [Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CSIC) and CIBER de Enfermedades Respiratorias (ISCIII), Madrid (Spain); Martín-Benito, Jaime, E-mail: jmartinb@cnb.csic.es [Department of Macromolecular Structures, Centro Nacional de Biotecnología (CSIC), Madrid (Spain)

    2015-05-15

    The group of Negative-Stranded RNA Viruses (NSVs) includes many human pathogens, like the influenza, measles, mumps, respiratory syncytial or Ebola viruses, which produce frequent epidemics of disease and occasional, high mortality outbreaks by transmission from animal reservoirs. The genome of NSVs consists of one to several single-stranded, negative-polarity RNA molecules that are always assembled into mega Dalton-sized complexes by association to many nucleoprotein monomers. These RNA-protein complexes or ribonucleoproteins function as templates for transcription and replication by action of the viral RNA polymerase and accessory proteins. Here we review our knowledge on these large RNA-synthesis machines, including the structure of their components, the interactions among them and their enzymatic activities, and we discuss models showing how they perform the virus transcription and replication programmes. - Highlights: • Overall organisation of NSV RNA synthesis machines. • Structure and function of the ribonucleoprotein components: Atomic structure of the RNA polymerase complex. • Commonalities and differences between segmented- and non-segmented NSVs. • Transcription versus replication programmes.

  16. Workplace Ergonomics Reference Guide

    Science.gov (United States)

    Workplace Ergonomics Reference Guide 2 nd Edition A Publication of the Computer/Electronic Accommodations Program Real Solutions for Real ... Table of Contents.................................................................................................................................. ... Checklist ........................................................................................................................... 3 Ergonomic ...

  17. Residual Resistivity Ratio (RRR) Measurements of LHC Superconducting NbTi Cable Strands

    CERN Document Server

    Charifoulline, Z

    2006-01-01

    The Rutherford-type superconducting NbTi cables of the LHC accelerator are currently manufactured by six industrial companies. As a part of the acceptance tests, the Residual Resistivity Ratio (RRR) of superconducting strands is systematically measured on virgin strands to qualify the strands before cabling and on extracted strands to qualify the cables and to check the final heat treatment (controlled oxidation to control interstrand resistance). More than 12000 samples of virgin and extracted strands have been measured during last five years. Results show good correlation with the measurements done by the companies and reflect well the technological process of cable production (strand annealing, cabling, cable heat treatment). This paper presents a description of the RRR-test station and the measurement procedure, the summary of the results over all suppliers and finally the correlation between RRR-values of the cables and the magnets.

  18. Estimation of Prestress Force Distribution in the Multi-Strand System of Prestressed Concrete Structures

    Directory of Open Access Journals (Sweden)

    Keunhee Cho

    2015-06-01

    Full Text Available Prestressed concrete (PSC is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM sensors to develop a method for tracking representative indicators of the prestress force using smart strands.

  19. Simulation of 125I induced DNA strand breaks in a CAP-DNA complex.

    Science.gov (United States)

    Li, W; Friedland, W; Jacob, P; Paretzke, H G; Panyutin, I; Neumann, R D

    2002-01-01

    The E. coli catabolite gene activator protein (CAP)-DNA complex with 125I located at the position of the H5 atom of the cytosine near the centre was incorporated into the PARTRAC track structure code. DNA strand breaks due to irradiation were calculated by track structure and radical attack simulations; strand breaks due to neutralisation of the highly charged 125Te ion were derived from a semi-empirical distribution. According to the calculations, the neutralisation effect dominates the strand breakage frequency at 2 bases away from the 125I decay site on both strands. The first breakage distribution counted from a 32P labelled end on the strand with 125I agreed well with experimental data, but on the opposite strand, the calculated distribution is more concentrated around the decay site and its yield is about 20% larger than the measured data.

  20. Regulation of UHRF1 by dual-strand tumor-suppressor microRNA-145 (miR-145-5p and miR-145-3p): inhibition of bladder cancer cell aggressiveness

    Science.gov (United States)

    Matsushita, Ryosuke; Yoshino, Hirofumi; Enokida, Hideki; Goto, Yusuke; Miyamoto, Kazutaka; Yonemori, Masaya; Inoguchi, Satoru; Nakagawa, Masayuki; Seki, Naohiko

    2016-01-01

    In microRNA (miRNA) biogenesis, the guide-strand of miRNA integrates into the RNA induced silencing complex (RISC), whereas the passenger-strand is inactivated through degradation. Analysis of our miRNA expression signature of bladder cancer (BC) by deep-sequencing revealed that microRNA (miR)-145-5p (guide-strand) and miR-145-3p (passenger-strand) were significantly downregulated in BC tissues. It is well known that miR-145-5p functions as a tumor suppressor in several types of cancer. However, the impact of miR-145-3p on cancer cells is still ambiguous. The aim of the present study was to investigate the functional significance of miR-145-3p and BC oncogenic pathways and targets regulated by miR-145-5p/miR-145-3p. Ectopic expression of either miR-145-5p or miR-145-3p in BC cells significantly suppressed cancer cell growth, migration and invasion and it also induced apoptosis. The gene encoding ubiquitin-like with PHD and ring finger domains 1 (UHRF1) was a direct target of these miRNAs. Silencing of UHRF1 induced apoptosis and inhibited cancer cell proliferation, migration, and invasion in BC cells. In addition, overexpressed UHRF1 was confirmed in BC clinical specimens, and the high UHRF1 expression group showed a significantly poorer cause specific survival rate in comparison with the low expression group. Taken together, our present data demonstrated that both strands of miR-145 (miR-145-5p: guide-strand and miR-145-3p: passenger-strand) play pivotal roles in BC cells by regulating UHRF1. The identification of the molecular target of a tumor suppressive miRNAs provides novel insights into the potential mechanisms of BC oncogenesis and suggests novel therapeutic strategies. PMID:27072587

  1. Asymmetric photoredox transition-metal catalysis activated by visible light

    Science.gov (United States)

    Huo, Haohua; Shen, Xiaodong; Wang, Chuanyong; Zhang, Lilu; Röse, Philipp; Chen, Liang-An; Harms, Klaus; Marsch, Michael; Hilt, Gerhard; Meggers, Eric

    2014-11-01

    Asymmetric catalysis is seen as one of the most economical strategies to satisfy the growing demand for enantiomerically pure small molecules in the fine chemical and pharmaceutical industries. And visible light has been recognized as an environmentally friendly and sustainable form of energy for triggering chemical transformations and catalytic chemical processes. For these reasons, visible-light-driven catalytic asymmetric chemistry is a subject of enormous current interest. Photoredox catalysis provides the opportunity to generate highly reactive radical ion intermediates with often unusual or unconventional reactivities under surprisingly mild reaction conditions. In such systems, photoactivated sensitizers initiate a single electron transfer from (or to) a closed-shell organic molecule to produce radical cations or radical anions whose reactivities are then exploited for interesting or unusual chemical transformations. However, the high reactivity of photoexcited substrates, intermediate radical ions or radicals, and the low activation barriers for follow-up reactions provide significant hurdles for the development of efficient catalytic photochemical processes that work under stereochemical control and provide chiral molecules in an asymmetric fashion. Here we report a highly efficient asymmetric catalyst that uses visible light for the necessary molecular activation, thereby combining asymmetric catalysis and photocatalysis. We show that a chiral iridium complex can serve as a sensitizer for photoredox catalysis and at the same time provide very effective asymmetric induction for the enantioselective alkylation of 2-acyl imidazoles. This new asymmetric photoredox catalyst, in which the metal centre simultaneously serves as the exclusive source of chirality, the catalytically active Lewis acid centre, and the photoredox centre, offers new opportunities for the `green' synthesis of non-racemic chiral molecules.

  2. Strand Burner Results of AFP-001 Propellant with Inert Coating for Temperature Compensation

    Science.gov (United States)

    2015-10-01

    ARL-MR-0907 ● OCT 2015 US Army Research Laboratory Strand Burner Results of AFP -001 Propellant with Inert Coating for Temperature...Laboratory Strand Burner Results of AFP -001 Propellant with Inert Coating for Temperature Compensation by John J Ritter and Anthony Canami...COVERED (From - To) February 2015 4. TITLE AND SUBTITLE Strand Burner Results of AFP -001 Propellant with Inert Coating for Temperature Compensation

  3. A Single-Strand Annealing Protein Clamps DNA to Detect and Secure Homology.

    OpenAIRE

    Marcel Ander; Sivaraman Subramaniam; Karim Fahmy; Francis Stewart, A.; Erik Schäffer

    2015-01-01

    Repair of DNA breaks by single-strand annealing (SSA) is a major mechanism for the maintenance of genomic integrity. SSA is promoted by proteins (single-strand-annealing proteins [SSAPs]), such as eukaryotic RAD52 and λ phage Redβ. These proteins use a short single-stranded region to find sequence identity and initiate homologous recombination. However, it is unclear how SSAPs detect homology and catalyze annealing. Using single-molecule experiments, we provide evidence that homology is recog...

  4. Analysis of Cable-in-Conduit Conductors' DC Performance in Light of Strand's Experimental Properties

    Institute of Scientific and Technical Information of China (English)

    TAN Yunfei; WENG Peide; LIU Fang; LI Shaolei

    2007-01-01

    Conductor qualification will be carried out with four Cable-in-Conduit Conductor (CICC) samples made of superconducting strands. The direct current (DC) performance of these samples will be tested in the SULTAN facility. The critical current densities of the strands can be well simulated by empirical equations. In this paper, a model is illustrated to predict the DC behaviour of the cable in light of the single strand's experimental properties. The simulation results were compared with experimental results.

  5. Interpreting the spatio-temporal patterns of sea turtle strandings: Going with the flow

    Science.gov (United States)

    Hart, K.M.; Mooreside, P.; Crowder, L.B.

    2006-01-01

    Knowledge of the spatial and temporal distribution of specific mortality sources is crucial for management of species that are vulnerable to human interactions. Beachcast carcasses represent an unknown fraction of at-sea mortalities. While a variety of physical (e.g., water temperature) and biological (e.g., decomposition) factors as well as the distribution of animals and their mortality sources likely affect the probability of carcass stranding, physical oceanography plays a major role in where and when carcasses strand. Here, we evaluate the influence of nearshore physical oceanographic and wind regimes on sea turtle strandings to decipher seasonal trends and make qualitative predictions about stranding patterns along oceanfront beaches. We use results from oceanic drift-bottle experiments to check our predictions and provide an upper limit on stranding proportions. We compare predicted current regimes from a 3D physical oceanographic model to spatial and temporal locations of both sea turtle carcass strandings and drift bottle landfalls. Drift bottle return rates suggest an upper limit for the proportion of sea turtle carcasses that strand (about 20%). In the South Atlantic Bight, seasonal development of along-shelf flow coincides with increased numbers of strandings of both turtles and drift bottles in late spring and early summer. The model also predicts net offshore flow of surface waters during winter - the season with the fewest relative strandings. The drift bottle data provide a reasonable upper bound on how likely carcasses are to reach land from points offshore and bound the general timeframe for stranding post-mortem (strandings follow a seasonal regime predictable from physical oceanography and mimicked by drift bottle experiments. Managers can use these findings to reevaluate incidental strandings limits and fishery takes for both nearshore and offshore mortality sources. ?? 2005 Elsevier Ltd. All rights reserved.

  6. Analysis of heavy-ion-induced DNA strand breaks in plasmid pUC18

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Plasmid DNA was irradiated or implanted by mixed particle field(CR) or lithium-ion-beam to detect strand breaks.The primary results showed that mixed particle field could induce single and double strand breaks with positive linear-dose-effects;most of sequence changes induced by CR were point mutant.Lithium-ion-beam could induce strand breaks also,but it was only at dose of 20Gy.

  7. Edwardsiella tarda sepsis in a live-stranded sperm whale (Physeter macrocephalus).

    Science.gov (United States)

    Cools, Piet; Haelters, Jan; Lopes dos Santos Santiago, Guido; Claeys, Geert; Boelens, Jerina; Leroux-Roels, Isabel; Vaneechoutte, Mario; Deschaght, Pieter

    2013-09-27

    Whale strandings remain poorly understood, although bacterial infections have been suggested to contribute. We isolated Edwardsiella tarda from the blood of a stranded sperm whale. The pathogen was identified with MALDI-TOF MS, confirmed by 16S rRNA gene sequencing and quantified in blood by qPCR. We report the first case of sepsis in a sperm whale. The zoonotic potential of E. tarda and the possible role of bacterial infections in the enigmatic strandings of cetaceans are discussed.

  8. Abbreviated guide pneumatic conveying design guide

    CERN Document Server

    Mills, David

    1990-01-01

    Abbreviated Guide: Pneumatic Conveying Design Guide describes the selection, design, and specification of conventional pneumatic conveying systems. The design procedure uses previous test data on the materials to be conveyed. The book also discusses system economics, operating costs, the choice of appropriate components or systems, system control, and system flexibility. The design system involves the type of conveying system for installation, the pipeline parameters, and also the plant components. System selection covers the properties of the material to be conveyed, plant layout, material pr

  9. Asymmetrical reinforcement and Wolbachia infection in Drosophila.

    Directory of Open Access Journals (Sweden)

    John Jaenike

    2006-10-01

    Full Text Available Reinforcement refers to the evolution of increased mating discrimination against heterospecific individuals in zones of geographic overlap and can be considered a final stage in the speciation process. One the factors that may affect reinforcement is the degree to which hybrid matings result in the permanent loss of genes from a species' gene pool. Matings between females of Drosophila subquinaria and males of D. recens result in high levels of offspring mortality, due to interspecific cytoplasmic incompatibility caused by Wolbachia infection of D. recens. Such hybrid inviability is not manifested in matings between D. recens females and D. subquinaria males. Here we ask whether the asymmetrical hybrid inviability is associated with a corresponding asymmetry in the level of reinforcement. The geographic ranges of D. recens and D. subquinaria were found to overlap across a broad belt of boreal forest in central Canada. Females of D. subquinaria from the zone of sympatry exhibit much stronger levels of discrimination against males of D. recens than do females from allopatric populations. In contrast, such reproductive character displacement is not evident in D. recens, consistent with the expected effects of unidirectional cytoplasmic incompatibility. Furthermore, there is substantial behavioral isolation within D. subquinaria, because females from populations sympatric with D. recens discriminate against allopatric conspecific males, whereas females from populations allopatric with D. recens show no discrimination against any conspecific males. Patterns of general genetic differentiation among populations are not consistent with patterns of behavioral discrimination, which suggests that the behavioral isolation within D. subquinaria results from selection against mating with Wolbachia-infected D. recens. Interspecific cytoplasmic incompatibility may contribute not only to post-mating isolation, an effect already widely recognized, but also to

  10. Structure-spectrophotometric selectivity relationship in interactions of quercetin related flavonoids with double stranded and single stranded RNA

    Science.gov (United States)

    Piantanida, Ivo; Mašić, Lozika; Rusak, Gordana

    2009-04-01

    Interactions of five flavonoids with dsRNA and single stranded ssRNA were studied by UV/vis titrations. The results obtained supported the intercalative binding mode as a dominant interaction of studied flavonoids with dsRNA as well as major interaction with ssRNA. Furthermore, changes of the UV/vis spectra of flavonoids induced by addition of poly G or poly C, respectively, are significantly stronger than changes induced by double stranded poly G-poly C, pointing to essential role of the free poly G or poly C sequence (not hydrogen bonded in double helix). Exclusively poly G caused significant batochromic shift of the UV/vis maxima of all studied flavonoids, whereby the intensity of batochromic shift is nicely correlated to the number of OH groups of flavonoid. Unlikely to poly G, addition of poly A and poly U induced measurable changes only in the UV/vis spectra of flavonoids characterised by no OH (galangin) or three OH groups (myricetin) on the phenyl part of the molecule. Consequently, flavonoids with one- or two-OH groups on the phenyl part of the molecule (luteolin, fisetin, kaempferol) specifically differentiate between poly A, poly U (negligible changes in the UV/Vis spectra) and poly G (strong changes in the UV/Vis spectra) as well as poly C (moderate changes in the UV/Vis spectra).

  11. Genetic requirements for the single-strand annealing pathway of double-strand break repair in Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, E.L.; Sugawara, N.; Haber, J.E. [Brandeis Univ., Waltham, MA (United States)] [and others

    1996-03-01

    HO endonuclease-induced double-strand breaks (DSBs) within a direct duplication of Escherichia coli lacZ genes are repaired either by gene conversion or by single-strand annealing (SSA), with >80% being SSA. Previously it was demonstrated that the RAD52 gene is required for DSB-induced SSA. In the present study, the effects of other genes belonging to the RAD52 epistasis group were analyzed. We show that RAD51, RAD54, RAD55, and RAD57 genes are not required for SSA irrespective of whether recombination occurred in plasmid or chromosomal DNA. In both plasmid and chromosomal constructs with homologous sequences in direct orientation, the proportion of SSA events over gene conversion was significantly elevated in the mutant strains. However, gene conversion was not affected when the two lacZ sequences were in inverted orientation. These results suggest that there is a competition between SSA and gene conversion processes that favors SSA in the absence of RAD51, RAD54, RAD55 and RAD57. Mutations in RAD50 and XRS2 genes do not prevent the completion, but markedly retard the kinetics, of DSB repair by both mechanisms in the lacZ direct repeat plasmid, a result resembling the effects of these genes during mating-type (MAT) switching. 43 refs., 8 figs., 3 tabs.

  12. A euryarchaeal histone modulates strand displacement synthesis by replicative DNA polymerases.

    Science.gov (United States)

    Sun, Fei; Huang, Li

    2016-07-01

    Euryarchaeota and Crenarchaeota, the two main lineages of the domain Archaea, encode different chromatin proteins and differ in the use of replicative DNA polymerases. Crenarchaea possess a single family B DNA polymerase (PolB), which is capable of strand displacement modulated by the chromatin proteins Cren7 and Sul7d. Euryarchaea have two distinct replicative DNA polymerases, PolB and PolD, a family D DNA polymerase. Here we characterized the strand displacement activities of PolB and PolD from the hyperthermophilic euryarchaeon Pyrococcus furiosus and investigated the influence of HPfA1, a homolog of eukaryotic histones from P. furiosus, on these activities. We showed that both PolB and PolD were efficient in strand displacement. HPfA1 inhibited DNA strand displacement by both DNA polymerases but exhibited little effect on the displacement of a RNA strand annealed to single-stranded template DNA. This is consistent with the finding that HPfA1 bound more tightly to double-stranded DNA than to a RNA:DNA hybrid. Our results suggest that, although crenarchaea and euryarchaea differ in chromosomal packaging, they share similar mechanisms in modulating strand displacement by DNA polymerases during lagging strand DNA synthesis.

  13. Workshop on effects of chromium coating on Nb{sub 3}Sn superconductor strand: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1994-04-12

    This report discusses the following topics: Chromium coating on superconductor strand -- an overview; technology of chromium plating; comparison of wires plated by different platers; search for chromium in copper; strand manufactures` presentations; chromium plating at the Lawrence Livermore National Laboratory; a first look at a chromium plating process development project tailored for T.P.X. and I.T.E.R. strand; and influence of chromium diffusion and related phenomena on the reference ratios of bare and chromium plated Nb{sub 3}Sn strand.

  14. Sequence Conversion by Single Strand Oligonucleotide Donors via Non-homologous End Joining in Mammalian Cells*

    OpenAIRE

    Liu, Jia; Majumdar, Alokes; Liu, Jilan; Thompson, Lawrence H.; Seidman, Michael M.

    2010-01-01

    Double strand breaks (DSBs) can be repaired by homology independent nonhomologous end joining (NHEJ) pathways involving proteins such as Ku70/80, DNAPKcs, Xrcc4/Ligase 4, and the Mre11/Rad50/Nbs1 (MRN) complex. DSBs can also be repaired by homology-dependent pathways (HDR), in which the MRN and CtIP nucleases produce single strand ends that engage homologous sequences either by strand invasion or strand annealing. The entry of ends into HDR pathways underlies protocols for genomic manipulatio...

  15. Sequence conversion by single strand oligonucleotide donors via non-homologous end joining in mammalian cells.

    Science.gov (United States)

    Liu, Jia; Majumdar, Alokes; Liu, Jilan; Thompson, Lawrence H; Seidman, Michael M

    2010-07-23

    Double strand breaks (DSBs) can be repaired by homology independent nonhomologous end joining (NHEJ) pathways involving proteins such as Ku70/80, DNAPKcs, Xrcc4/Ligase 4, and the Mre11/Rad50/Nbs1 (MRN) complex. DSBs can also be repaired by homology-dependent pathways (HDR), in which the MRN and CtIP nucleases produce single strand ends that engage homologous sequences either by strand invasion or strand annealing. The entry of ends into HDR pathways underlies protocols for genomic manipulation that combine site-specific DSBs with appropriate informational donors. Most strategies utilize long duplex donors that participate by strand invasion. Work in yeast indicates that single strand oligonucleotide (SSO) donors are also active, over considerable distance, via a single strand annealing pathway. We examined the activity of SSO donors in mammalian cells at DSBs induced either by a restriction nuclease or by a targeted interstrand cross-link. SSO donors were effective immediately adjacent to the break, but activity declined sharply beyond approximately 100 nucleotides. Overexpression of the resection nuclease CtIP increased the frequency of SSO-mediated sequence modulation distal to the break site, but had no effect on the activity of an SSO donor adjacent to the break. Genetic and in vivo competition experiments showed that sequence conversion by SSOs in the immediate vicinity of the break was not by strand invasion or strand annealing pathways. Instead these donors competed for ends that would have otherwise entered NHEJ pathways.

  16. Necropsy report of a fin whale (Balaenoptera physalus) stranded in Denmark in 2010

    DEFF Research Database (Denmark)

    Alstrup, Aage K. O.; Hedayat, Abdi; Jensen, Trine Hammer;

    2013-01-01

    There is little detailed information on stranded fin whales (Balaenoptera physalus) in the scientific literature (Notarbartolo di Sciara et al., 2003). In Denmark, at least eight fin whales stranded between the years 1603 and 1958 (Kinze, 1995). On 16 June 2010, a live subadult or adult male fin...... whale stranded in the Bay of Vejle (55º 69' N, 9º 58' E), Denmark. Despite several attempts, it was not possible to rescue the fin whale, which was only partially exposed by the water. The fin whale succumbed after 5 d stranded in shallow water. The dead fin whale was transported to a nearby pier...

  17. Transport AC loss characteristics of a nine strand YBCO Roebel cable

    Science.gov (United States)

    Jiang, Zhenan; Badcock, R. A.; Long, N. J.; Staines, Mike; Thakur, K. P.; Lakshmi, L. S.; Wright, A.; Hamilton, K.; Sidorov, G. N.; Buckley, R. G.; Amemiya, Naoyuki; Caplin, A. D.

    2010-02-01

    Transport AC loss in a short length of 9/2 YBCO Roebel cable (nine 2 mm wide strands) is measured. The AC loss data are compared with those in a 5/2 YBCO Roebel cable (five 2 mm wide strands) as well as that in a single strand. All the strands composing the cables and the single strand are insulated and cut from the same stock material. The validity of the measurement method was reconfirmed by results at a range of frequencies. At a wide range of It/Ic, the normalized AC losses in the Roebel cable were around 6.2-6.7 times of those in the single strand. This is less than the nine times predicted for a tight bundle of nine conductors. The normalized transport AC losses in the 5/2 Roebel cable are much smaller than those in the 9/2 Roebel. This should be due to larger superposition of magnetic field in the 9/2 Roebel. The Ic of the 9/2 and 5/2 Roebel cables is determined by serial connection of the strands. This eliminates the effect where differing resistances in the current terminations cause uneven current sharing between strands when the strands are connected in parallel.

  18. Trends in Marine Turtle Strandings along the East Queensland, Australia Coast, between 1996 and 2013

    Directory of Open Access Journals (Sweden)

    Jaylene Flint

    2015-01-01

    Full Text Available In-water monitoring of marine vertebrates is usually expensive while the use of stranding data can be used to provide a cost-effective estimation of disease and mortality. Strandings for Queensland are recorded in a web based database (StrandNet managed by the Queensland Government’s Department of Environment and Heritage Protection (EHP. Data recorded in StrandNet from the east coast of Queensland between 1996 and 2013 were investigated for patterns of stranding. Significant trends in Queensland over this time were (i an increase in the number of animals reported stranded within this study site; (ii a species (loggerhead and green marine turtles prevalence; (iii a seasonal effect on different age classes stranding with most overall strandings occurring between August and November; and (iv stranding hotspots (Moreton Bay, Hervey Bay, Rockhampton region, and Cleveland Bays persisting throughout the study timeframe. This study suggested that intervention strategies, such as rehabilitation, should be able to be focussed on periods of heightened importance and specific localities to minimize health risks and contribute to sustainable use of resources.

  19. Polycation graft copolymers accelerating DNA strand exchange: involvement of ionic interaction.

    Science.gov (United States)

    Kim, W J; Ishihara, T; Akaike, T; Maruyama, A

    2001-01-01

    In the previous study (Chem. Eur. J., 7, 176 (2001)) we demonstrated that the comb-type polycationic copolymer (PLL-g-Dex) which is composed of poly (L-lysine) backbone and dextran graft chains expedited the DNA strand exchange reaction. In this study, fluorescence resonance energy transfer (FRET) was employed to explore the copolymer-mediated DNA strand exchange with higher time-resolution. To initiate strand exchange reaction the duplex prepared from 3'-fluorescein isothiocyanate (FITC)--and 5'-carboxytetramethylrhodamine(TAMRA)-labeled complementary DNAs was added to its non-labeled complementary single strand. DNA strand exchange was monitored by observing the recovery of the FITC quenching. More than 20,000 times increase in strand exchange rate at 37 degrees C by the copolymer was estimated. To investigate the accelerating mechanisms of the copolymer, the same reactions but at various ionic strenghts were studied. With increasing ionic strengths the strand exchange rate in the absence of the copolymer increased, suggesting that ionic repulsion among DNAs is unfavorable for the strand exchange to occur. Hence, alleviation of the electrostatic repulsion through interpolyelectrolyte complex formation is probably a role of the copolymer for accelerating the strand exchange reaction.

  20. Single-stranded regions in transforming deoxyribonucleic acid after uptake by competent Haemophilus influenzae

    Energy Technology Data Exchange (ETDEWEB)

    Sedgwick, B.; Setlow, J.K.

    1976-02-01

    About 15% of donor deoxyribonucleic acid (DNA) is single stranded immediately after uptake into competent Haemophilus influenzae wild-type cells, as judged by its sensitivity to S1 endonuclease. This amount decreases to 4 to 5% by 30 min after uptake. Mutants which are defective in the covalent association of recipient and donor DNA form little or no S1 endonuclease-sensitive donor. At 17 C donor DNA taken up by the wild type contains single-stranded regions although there is no observable association, either covalent or noncovalent. The single-stranded regions are at the ends of donor DNA molecules, as judged by the unchanged sedimentation velocity after S1 endonuclease digestion. The amount of single-stranded donor remains constant at 17 C for more than 60 min after uptake, suggesting that the decrease observed at 37 C is the result of association of single-stranded ends with single-stranded regions of recipient cell DNA. Three sequential steps necessary for the integration of donor DNA into recipient DNA are proposed: the synthesis of single-stranded regions in recipient DNA, the interaction of donor DNA with recipient DNA resulting in the production of single-stranded ends on donor DNA, and the stable pairing of homologous single-stranded regions. (auth)

  1. BONES, TEACHER'S GUIDE.

    Science.gov (United States)

    Elementary Science Study, Newton, MA.

    THIS GUIDE WAS DEVELOPED FOR USE WITH THE ELEMENTARY SCIENCE STUDY UNIT ON "BONES.""BONES" HAS BEEN TAUGHT IN THE FOURTH GRADE AND REQUIRES FROM 10 TO 25 LESSONS, DEPENDING ON THE NUMBER OF ACTIVITIES USED. THE GUIDE DOES NOT PROVIDE DETAILED INSTRUCTION FOR CONDUCTING CLASSES, BUT RATHER SOME POSSIBLE ACTIVITIES, AND LEAVES THE DAY-TO-DAY…

  2. Radiologic Technology Program Guide.

    Science.gov (United States)

    Georgia Univ., Athens. Dept. of Vocational Education.

    This guide presents the standard curriculum for technical institutes in Georgia. The curriculum addresses the minimum competencies for a radiologic technology program. The guide contains four major sections. The General Information section contains an introduction giving an overview and defining purpose and objectives; a program description,…

  3. Irrigation Systems. Student's Guide.

    Science.gov (United States)

    Amarillo Coll., TX.

    This guide is intended for use by individuals preparing for a career in commercial and residential irrigation. The materials included are geared toward students who have had some experience in the irrigation business; they are intended to be presented in 10 six-hour sessions. The first two sections deal with using this guide and preparing for the…

  4. Irrigation Systems. Instructor's Guide.

    Science.gov (United States)

    Amarillo Coll., TX.

    This guide is intended for use by licensed irrigators who wish to teach others how to design and install residential and commercial irrigation systems. The materials included in the guide have been developed under the assumption that the instructors who use it have little or no formal training as teachers. The first section presents detailed…

  5. Instructional Guide for Cosmetology.

    Science.gov (United States)

    Virginia Polytechnic Inst. and State Univ., Blacksburg. Dept. of Education.

    Intended as a tool for cosmetology teachers in Virginia public and private schools, the document is an instructional guide which offers 12 units of study, arranged in a three year course. Materials covered help prepare students for licensure in the State of Virginia and the guide is designed to cover the 1,500 hours required to be spent in the…

  6. Measurement Practice Guide

    Science.gov (United States)

    College and Career Readiness and Success Center, 2014

    2014-01-01

    This discussion guide is part of a larger practice guide designed to help state education agencies (SEAs) define measurement goals, select college and career readiness measures and indicators designed to support those goals, and use the data gathered with those measures and indicators to make informed decisions about college and career readiness…

  7. Nutrition Guide for Toddlers

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Nutrition Guide for Toddlers KidsHealth > For Parents > Nutrition Guide ... español Guía de nutrición para sus hijos pequeños Nutrition Through Variety Growth slows somewhat during the toddler ...

  8. The Higgs hunter's guide

    CERN Document Server

    Gunion, John F; Haber, Howard E; Kane, Gordon L

    1989-01-01

    The Higgs Hunter's Guide is a definitive and comprehensive guide to the physics of Higgs bosons. In particular, it discusses the extended Higgs sectors required by those recent theoretical approaches that go beyond the Standard Model, including supersymmetry and superstring-inspired models.

  9. JBoss ESB Beginner's Guide

    CERN Document Server

    DiMaggio, Len; Magesh, Kumar

    2012-01-01

    Part of Packt's Beginner's Guide series, each chapter contains practical examples with step-by-step instructions and plenty of screenshots to guide you through the implementation of JBoss ESB. This book is intended for Java programmers although you don't need previous experience with middleware such as application servers or ESBs.

  10. Guided Learning at Work.

    Science.gov (United States)

    Billett, Stephen

    2000-01-01

    Guided learning (questioning, diagrams/analogies, modeling, coaching) was studied through critical incident interviews in five workplaces. Participation in everyday work activities was the most effective contributor to workplace learning. Organizational readiness and the efficacy of guided learning in resolving novel tasks were also important. (SK)

  11. Medical Assisting Program Guide.

    Science.gov (United States)

    Georgia Univ., Athens. Dept. of Vocational Education.

    This guide presents the standard curriculum for technical institutes in Georgia. The curriculum addresses the minimum competencies for a medical assisting program. The program guide is designed to relate primarily to the development of those skills needed by individuals in the medical assisting field, such as medical law and ethics, typing,…

  12. Marketing Education Curriculum Guide.

    Science.gov (United States)

    Michigan State Univ., East Lansing. Coll. of Agriculture and Natural Resources Education Inst.

    This curriculum guide is intended to provide a common core of competencies from which to design an effective secondary marketing education program. Introductory materials include a definition of marketing education, objectives, outline of instructional content, and questions and answers regarding the curriculum guide. These practical materials are…

  13. concrete5 Beginner's Guide

    CERN Document Server

    Laubacher, Remo

    2011-01-01

    This book is part of Packt's Beginner's Guide series. You will be guided through the set up of a Concrete5 site with step-by-step practical examples. This book is ideal for developers who would like to build their first site with Concrete5. Some k

  14. 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.

  15. Performance of JPEG Image Transmission Using Proposed Asymmetric Turbo Code

    Directory of Open Access Journals (Sweden)

    Mohamad Yusoff Alias

    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 (176×144 “Suzie” image. The recursive systematic convolutional (RSC encoder with generator polynomials (1,D3+D2+1/D3+D+1, 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 (1,D3+D2+1/D3+D+1;D3+D2+1/D3+1, 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 N=400, code rate r=1/3 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.

  16. Thermal transport across symmetric and asymmetric solid-solid interfaces

    Science.gov (United States)

    Bi, Kedong; Liu, Yadong; Zhang, Chunwei; Li, Jiapeng; Chen, Minhua; Chen, Yunfei

    2016-10-01

    Thermal transport across symmetric and asymmetric solid-solid interfaces is investigated by non-equilibrium molecular dynamics simulations. For symmetric interfaces, simulation results demonstrate that the thermal interface resistance is reduced greatly with the temperature increasing from 20 to 70 K. Besides, the introduction of an interlayer in the region of a highly mismatched interface is predicted to effectively decrease the thermal interface resistance due to the vibrational bridge role of the interlayer in connecting two vibrationally mismatched materials. As for the case of asymmetric interfaces, it is found that the capacity of thermal transport across an asymmetric interface is related to the effective interfacial area, namely the smaller cross-section area of component materials. In addition, effects of the transition angle at asymmetric interfaces on the thermal interface resistance are further studied when heat flows through interfaces from the side with larger cross-section area to the other. It is shown that a smoother transition is preferred for thermal transport through an asymmetric interface.

  17. Success Factors of Asymmetric Connections - Example of Large Slovenian Enterprises

    Directory of Open Access Journals (Sweden)

    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.

  18. Convergent transmission of RNAi guide-target mismatch information across Argonaute internal allosteric network.

    Directory of Open Access Journals (Sweden)

    Thomas T Joseph

    Full Text Available In RNA interference, a guide strand derived from a short dsRNA such as a microRNA (miRNA is loaded into Argonaute, the central protein in the RNA Induced Silencing Complex (RISC that silences messenger RNAs on a sequence-specific basis. The positions of any mismatched base pairs in an miRNA determine which Argonaute subtype is used. Subsequently, the Argonaute-guide complex binds and silences complementary target mRNAs; certain Argonautes cleave the target. Mismatches between guide strand and the target mRNA decrease cleavage efficiency. Thus, loading and silencing both require that signals about the presence of a mismatched base pair are communicated from the mismatch site to effector sites. These effector sites include the active site, to prevent target cleavage; the binding groove, to modify nucleic acid binding affinity; and surface allosteric sites, to control recruitment of additional proteins to form the RISC. To examine how such signals may be propagated, we analyzed the network of internal allosteric pathways in Argonaute exhibited through correlations of residue-residue interactions. The emerging network can be described as a set of pathways emanating from the core of the protein near the active site, distributed into the bulk of the protein, and converging upon a distributed cluster of surface residues. Nucleotides in the guide strand "seed region" have a stronger relationship with the protein than other nucleotides, concordant with their importance in sequence selectivity. Finally, any of several seed region guide-target mismatches cause certain Argonaute residues to have modified correlations with the rest of the protein. This arises from the aggregation of relatively small interaction correlation changes distributed across a large subset of residues. These residues are in effector sites: the active site, binding groove, and surface, implying that direct functional consequences of guide-target mismatches are mediated through the

  19. Convergent Transmission of RNAi Guide-Target Mismatch Information across Argonaute Internal Allosteric Network

    Science.gov (United States)

    Joseph, Thomas T.; Osman, Roman

    2012-01-01

    In RNA interference, a guide strand derived from a short dsRNA such as a microRNA (miRNA) is loaded into Argonaute, the central protein in the RNA Induced Silencing Complex (RISC) that silences messenger RNAs on a sequence-specific basis. The positions of any mismatched base pairs in an miRNA determine which Argonaute subtype is used. Subsequently, the Argonaute-guide complex binds and silences complementary target mRNAs; certain Argonautes cleave the target. Mismatches between guide strand and the target mRNA decrease cleavage efficiency. Thus, loading and silencing both require that signals about the presence of a mismatched base pair are communicated from the mismatch site to effector sites. These effector sites include the active site, to prevent target cleavage; the binding groove, to modify nucleic acid binding affinity; and surface allosteric sites, to control recruitment of additional proteins to form the RISC. To examine how such signals may be propagated, we analyzed the network of internal allosteric pathways in Argonaute exhibited through correlations of residue-residue interactions. The emerging network can be described as a set of pathways emanating from the core of the protein near the active site, distributed into the bulk of the protein, and converging upon a distributed cluster of surface residues. Nucleotides in the guide strand “seed region” have a stronger relationship with the protein than other nucleotides, concordant with their importance in sequence selectivity. Finally, any of several seed region guide-target mismatches cause certain Argonaute residues to have modified correlations with the rest of the protein. This arises from the aggregation of relatively small interaction correlation changes distributed across a large subset of residues. These residues are in effector sites: the active site, binding groove, and surface, implying that direct functional consequences of guide-target mismatches are mediated through the cumulative

  20. Evaluation of an asymmetric stent patch design for a patient specific intracranial aneurysm using computational fluid dynamic (CFD) calculations in the computed tomography (CT) derived lumen

    Science.gov (United States)

    Kim, Minsuok; Ionita, Ciprian; Tranquebar, Rekha; Hoffmann, Kenneth R.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

    2006-03-01

    Stenting may provide a new, less invasive therapeutic option for cerebral aneurysms. However, a conventional porous stent may be insufficient in modifying the blood flow for clinical aneurysms. We designed an asymmetric stent consisting of a low porosity patch welded onto a porous stent for an anterior cerebral artery aneurysm of a specific patient geometry to block the strong inflow jet. To evaluate the effect of the patch on aneurysmal flow dynamics, we "virtually" implanted it into the patient's aneurysm geometry and performed Computational Fluid Dynamics (CFD) analysis. The patch was computationally deformed to fit into the vessel lumen segmented from the patient CT reconstructions. After the flow calculations, a patch with the same design was fabricated using laser cutting techniques and welded onto a commercial porous stent, creating a patient-specific asymmetric stent. This stent was implanted into a phantom, which was imaged with X-ray angiography. The hemodynamics of untreated and stented aneurysms were compared both computationally and experimentally. It was found from CFD of the patient aneurysm that the asymmetric stent effectively blocked the strong inflow jet into the aneurysm and eliminated the flow impingement on the aneurysm wall at the dome. The impact zone with elevated wall shear stress was eliminated, the aneurysmal flow activity was substantially reduced, and the flow was considerably reduced. Experimental observations corresponded well qualitatively with the CFD results. The demonstrated asymmetric stent could lead to a new minimally invasive image guided intervention to reduce aneurysm growth and rupture.

  1. Regulatory RNA design through evolutionary computation and strand displacement.

    Science.gov (United States)

    Rostain, William; Landrain, Thomas E; Rodrigo, Guillermo; Jaramillo, Alfonso

    2015-01-01

    The discovery and study of a vast number of regulatory RNAs in all kingdoms of life over the past decades has allowed the design of new synthetic RNAs that can regulate gene expression in vivo. Riboregulators, in particular, have been used to activate or repress gene expression. However, to accelerate and scale up the design process, synthetic biologists require computer-assisted design tools, without which riboregulator engineering will remain a case-by-case design process requiring expert attention. Recently, the design of RNA circuits by evolutionary computation and adapting strand displacement techniques from nanotechnology has proven to be suited to the automated generation of DNA sequences implementing regulatory RNA systems in bacteria. Herein, we present our method to carry out such evolutionary design and how to use it to create various types of riboregulators, allowing the systematic de novo design of genetic control systems in synthetic biology.

  2. Electronic transport in double-strand DNA segments

    Science.gov (United States)

    Albuquerque, E. L.; Mauriz, P. W.; Moreira, D. A.

    2008-03-01

    We report in this work a numerical study of the electronic density of states in π-stacked arrays of DNA double-strand segments made up from the nucleotides guanine G, adenine A, cytosine C and thymine T. In order to reveal the relevance of the underlying correlations in the nucleotides distribution, we compare the results for a genomic DNA sequence, considering a segment of the first sequenced human chromosome 22 (Ch 22), with those of two artificial sequences forming a Rudin-Shapiro (RS) as well as a Fibonacci (FB) polyGC quasiperiodic sequences. Our theoretical method uses an electronic tight-binding Hamiltonian suitable to describe the DNA segments modeled by the quasiperiodic chains.

  3. Current-voltage characteristics of double-strand DNA sequences

    Science.gov (United States)

    Bezerril, L. M.; Moreira, D. A.; Albuquerque, E. L.; Fulco, U. L.; de Oliveira, E. L.; de Sousa, J. S.

    2009-09-01

    We use a tight-binding formulation to investigate the transmissivity and the current-voltage (I-V) characteristics of sequences of double-strand DNA molecules. In order to reveal the relevance of the underlying correlations in the nucleotides distribution, we compare the results for the genomic DNA sequence with those of artificial sequences (the long-range correlated Fibonacci and Rudin-Shapiro one) and a random sequence, which is a kind of prototype of a short-range correlated system. The random sequence is presented here with the same first neighbors pair correlations of the human DNA sequence. We found that the long-range character of the correlations is important to the transmissivity spectra, although the I-V curves seem to be mostly influenced by the short-range correlations.

  4. Molecular dynamics simulations of a single stranded (ss) DNA

    CERN Document Server

    Chatterjee, Subhasish; Thakur, Siddarth; Burin, Alexander

    2012-01-01

    The objective of the present study was to develop an understanding of short single-stranded DNA (ssDNA) to assist the development of new DNA-based biosensors. A ssDNA model containing twelve bases was constructed from the 130-145 codon sequence of the p53 gene. Various thermodynamic macroscopic observables such as temperature, energy distributions, as well as root mean square deviation (RMSD) of the nucleic acid backbone of the ssDNA were studied using molecular dynamics (MD) simulations. The AMBER program was used for building the structural model of the ssDNA, and atomistic MD simulations in three different ensembles were carried out using the NAMD program. The microcanonical (NVE), conical (NVT) and isobaric-isothermal (NPT) ensembles were employed to compare the equilibrium characteristics of ssDNA in aqueous solutions. Our results indicate that the conformational stability of the ssDNA is dependent on the thermodynamic conditions.

  5. Phosphorylation: The Molecular Switch of Double-Strand Break Repair

    Directory of Open Access Journals (Sweden)

    K. C. Summers

    2011-01-01

    Full Text Available Repair of double-stranded breaks (DSBs is vital to maintaining genomic stability. In mammalian cells, DSBs are resolved in one of the following complex repair pathways: nonhomologous end-joining (NHEJ, homologous recombination (HR, or the inclusive DNA damage response (DDR. These repair pathways rely on factors that utilize reversible phosphorylation of proteins as molecular switches to regulate DNA repair. Many of these molecular switches overlap and play key roles in multiple pathways. For example, the NHEJ pathway and the DDR both utilize DNA-PK phosphorylation, whereas the HR pathway mediates repair with phosphorylation of RPA2, BRCA1, and BRCA2. Also, the DDR pathway utilizes the kinases ATM and ATR, as well as the phosphorylation of H2AX and MDC1. Together, these molecular switches regulate repair of DSBs by aiding in DSB recognition, pathway initiation, recruitment of repair factors, and the maintenance of repair mechanisms.

  6. Membranous Replication Factories Induced by Plus-Strand RNA Viruses

    Directory of Open Access Journals (Sweden)

    Inés Romero-Brey

    2014-07-01

    Full Text Available In this review, we summarize the current knowledge about the membranous replication factories of members of plus-strand (+ RNA viruses. We discuss primarily the architecture of these complex membrane rearrangements, because this topic emerged in the last few years as electron tomography has become more widely available. A general denominator is that two “morphotypes” of membrane alterations can be found that are exemplified by flaviviruses and hepaciviruses: membrane invaginations towards the lumen of the endoplasmatic reticulum (ER and double membrane vesicles, representing extrusions also originating from the ER, respectively. We hypothesize that either morphotype might reflect common pathways and principles that are used by these viruses to form their membranous replication compartments.

  7. Using both strands: The fundamental nature of antisense transcription.

    Science.gov (United States)

    Murray, Struan C; Mellor, Jane

    2016-01-01

    Non-coding transcription across the antisense strands of genes is an abundant, pervasive process in eukaryotes from yeast to humans, however its biological function remains elusive. Here, we provide commentary on a recent study of ours, which demonstrates a genome-wide role for antisense transcription: establishing a unique, dynamic chromatin architecture over genes. Antisense transcription increases the level of nucleosome occupancy and histone acetylation at the promoter and body of genes, without necessarily modulating the level of protein-coding sense transcription. It is also associated with high levels of histone turnover. By allowing genes to sample a wider range of chromatin configurations, antisense transcription could serve to make genes more sensitive to changing signals, priming them for responses to developmental programs or stressful cellular environments. Given the abundance of antisense transcription and the breadth of these chromatin changes, we propose that antisense transcription represents a fundamental, canonical feature of eukaryotic genes.

  8. Electronic transport in double-strand DNA segments

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, E L; Moreira, D A [Departamento de Fisica, Universidade Federal do Rio Grande do Norte 59072-970 Natal-RN (Brazil); Mauriz, P W [Departamento de Ciencias Exatas, Centro Federal de Educacao Tecnologica do Maranhao 65025-001 Sao Luis-MA (Brazil)], E-mail: eudenilson@dfte.ufrn.br

    2008-03-15

    We report in this work a numerical study of the electronic density of states in {pi}-stacked arrays of DNA double-strand segments made up from the nucleotides guanine G, adenine A, cytosine C and thymine T. In order to reveal the relevance of the underlying correlations in the nucleotides distribution, we compare the results for a genomic DNA sequence, considering a segment of the first sequenced human chromosome 22 (Ch 22), with those of two artificial sequences forming a Rudin-Shapiro (RS) as well as a Fibonacci (FB) polyGC quasiperiodic sequences. Our theoretical method uses an electronic tight-binding Hamiltonian suitable to describe the DNA segments modeled by the quasiperiodic chains.

  9. Current-voltage characteristics of double-strand DNA sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bezerril, L.M.; Moreira, D.A. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970, Natal-RN (Brazil); Albuquerque, E.L., E-mail: eudenilson@dfte.ufrn.b [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970, Natal-RN (Brazil); Fulco, U.L. [Departamento de Biofisica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970, Natal-RN (Brazil); Oliveira, E.L. de; Sousa, J.S. de [Departamento de Fisica, Universidade Federal do Ceara, 60455-760, Fortaleza-CE (Brazil)

    2009-09-07

    We use a tight-binding formulation to investigate the transmissivity and the current-voltage (I-V) characteristics of sequences of double-strand DNA molecules. In order to reveal the relevance of the underlying correlations in the nucleotides distribution, we compare the results for the genomic DNA sequence with those of artificial sequences (the long-range correlated Fibonacci and Rudin-Shapiro one) and a random sequence, which is a kind of prototype of a short-range correlated system. The random sequence is presented here with the same first neighbors pair correlations of the human DNA sequence. We found that the long-range character of the correlations is important to the transmissivity spectra, although the I-V curves seem to be mostly influenced by the short-range correlations.

  10. Sulforaphane induces DNA single strand breaks in cultured human cells

    Energy Technology Data Exchange (ETDEWEB)

    Sestili, Piero, E-mail: piero.sestili@uniurb.it [Dipartimento di Scienze Biomolecolari, Via Maggetti, 21, Universita degli Studi di Urbino ' Carlo Bo' , 61029 Urbino, PU (Italy); Paolillo, Marco [Dipartimento di Scienze Biomolecolari, Via Maggetti, 21, Universita degli Studi di Urbino ' Carlo Bo' , 61029 Urbino, PU (Italy); Lenzi, Monia [Dipartimento di Farmacologia, Universita degli Studi di Bologna, Via Irnerio 48, 40126 Bologna (Italy); Colombo, Evelin; Vallorani, Luciana; Casadei, Lucia; Martinelli, Chiara [Dipartimento di Scienze Biomolecolari, Via Maggetti, 21, Universita degli Studi di Urbino ' Carlo Bo' , 61029 Urbino, PU (Italy); Fimognari, Carmela [Dipartimento di Farmacologia, Universita degli Studi di Bologna, Via Irnerio 48, 40126 Bologna (Italy)

    2010-07-07

    Sulforaphane (SFR), an isothiocyanate from cruciferous vegetables, possesses growth-inhibiting and apoptosis-inducing activities in cancer cell lines. Recently, SFR has been shown to promote the mitochondrial formation of reactive oxygen species (ROS) in human cancer cell lines. The present study was undertaken to see whether SFR-derived ROS might cause DNA damage in cultured human cells, namely T limphoblastoid Jurkat and human umbilical vein endothelial cells (HUVEC). 1-3 h treatments with 10-30 {mu}M SFR elicited intracellular ROS formation (as assayed with dihydrorhodamine, DHR, oxidation) as well as DNA breakage (as assessed with fast halo assay, FHA). These effects lacked cell-type specificity, since could be observed in both Jurkat and HUVEC. Differential-pH FHA analysis of damaged DNA showed that SFR causes frank DNA single strand breaks (SSBs); no DNA double strand breaks (DSBs) were found within the considered treatment times (up to 3 h). SFR-derived ROS were formed at the mitochondrial respiratory chain (MRC) level: indeed rotenone or myxothiazol (MRC Complex I and III inhibitors, respectively) abrogated ROS formation. Furthermore ROS were not formed in Jurkat cells pharmacologically depleted of respiring mitochondria (MRC-/Jurkat). Formation of ROS was causally linked to the induction of SSBs: indeed all the experimental conditions capable of preventing ROS formation also prevented the damage of nuclear DNA from SFR-intoxicated cells. As to the toxicological relevance of SSBs, we found that their prevention slightly but significantly attenuated SFR cytotoxicity, suggesting that high-dose SFR toxicity is the result of a complex series of events among which GSH depletion seems to play a pivotal role. In conclusion, the present study identifies a novel mechanism contributing to SFR toxicity which - since DNA damage is a prominent mechanism underlying the cytotoxic activity of established antineoplastic agents - might help to exploit the therapeutic value

  11. Plasmon coupling of magnetic resonances in an asymmetric gold semishell

    Science.gov (United States)

    Ye, Jian; Kong, Yan; Liu, Cheng

    2016-05-01

    The generation of magnetic dipole resonances in metallic nanostructures is of great importance for constructing near-zero or even negative refractive index metamaterials. Commonly, planar two-dimensional (2D) split-ring resonators or relevant structures are basic elements of metamaterials. In this work, we introduce a three-dimensional (3D) asymmetric Au semishell composed of two nanocups with a face-to-face geometry and demonstrate two distinct magnetic resonances spontaneously in the visible-near infrared optical wavelength regime. These two magnetic resonances are from constructive and destructive hybridization of magnetic dipoles of individual nanocups in the asymmetric semishell. In contrast, complete cancellation of magnetic dipoles in the symmetric semishell leads to only a pronounced electric mode with near-zero magnetic dipole moment. These 3D asymmetric resonators provide new ways for engineering hybrid resonant modes and ultra-high near-field enhancement for the design of 3D metamaterials.

  12. Experimental Quantification of Asymmetric Einstein-Podolsky-Rosen Steering.

    Science.gov (United States)

    Sun, Kai; Ye, Xiang-Jun; Xu, Jin-Shi; Xu, Xiao-Ye; Tang, Jian-Shun; Wu, Yu-Chun; Chen, Jing-Ling; Li, Chuan-Feng; Guo, Guang-Can

    2016-04-22

    Einstein-Podolsky-Rosen (EPR) steering describes the ability of one observer to nonlocally "steer" the other observer's state through local measurements. EPR steering exhibits a unique asymmetric property; i.e., the steerability can differ between observers, which can lead to one-way EPR steering in which only one observer obtains steerability in the steering process. This property is inherently different from the symmetric concepts of entanglement and Bell nonlocality, and it has attracted increasing interest. Here, we experimentally demonstrate asymmetric EPR steering for a class of two-qubit states in the case of two measurement settings. We propose a practical method to quantify the steerability. We then provide a necessary and sufficient condition for EPR steering and clearly demonstrate one-way EPR steering. Our work provides new insight into the fundamental asymmetry of quantum nonlocality and has potential applications in asymmetric quantum information processing.

  13. Multiband Asymmetric Transmission of Airborne Sound by Coded Metasurfaces

    Science.gov (United States)

    Xie, Boyang; Cheng, Hua; Tang, Kun; Liu, Zhengyou; Chen, Shuqi; Tian, Jianguo

    2017-02-01

    We present the design, characterization, and theoretical and experimental demonstration of multiband asymmetric transmission of airborne sound using an ultrathin coded metasurface formed by an alternating arrangement of the coding elements 0 and 1. The asymmetric transmission effect can be easily controlled to selectively achieve off and on by coding different patterns. Both frequency- and angle-selective transmission is discussed. The proposed multiband asymmetric transmission stems from the constructive and destructive interferences of acoustic-wave coupling between the coded elements. The experimental results are in relative agreement with numerical simulations. This work opens an alternative path for ultrathin acoustic-device design and shows promise for application in acoustic rectification and noise control.

  14. 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.

  15. New Asymmetric Fuzzy PID Control for Pneumatic Position Control System

    Institute of Scientific and Technical Information of China (English)

    薛阳; 彭光正; 范萌; 伍清河

    2004-01-01

    A fuzzy control algorithm of asymmetric fuzzy strategy is introduced for a servo-pneumatic position system. It can effectively solve the difficult problems of single rod low friction cylinders, which are mainly caused by asymmetric structures and different friction characteristics in two directions. On the basis of this algorithm, a traditional PID control is used to improve dynamic performance. Furthermore, a new asymmetric fuzzy PID control with α factor is advanced to improve the self-adaptability and robustness of the system. Both the theoretical analyses and experimental results prove that, with this control strategy, the dynamic performance of the system can be greatly improved. The system using this control algorithm has strong robustness and it obtains desired overshoot and repeatability in both transient and steady-state responses.

  16. Phase-transfer-catalysed asymmetric synthesis of tetrasubstituted allenes

    Science.gov (United States)

    Hashimoto, Takuya; Sakata, Kazuki; Tamakuni, Fumiko; Dutton, Mark J.; Maruoka, Keiji

    2013-03-01

    Allenes are molecules based on three carbons connected by two cumulated carbon-carbon double bonds. Given their axially chiral nature and unique reactivity, substituted allenes have a variety of applications in organic chemistry as key synthetic intermediates and directly as part of biologically active compounds. Although the demands for these motivated many endeavours to make axially chiral, substituted allenes by exercising asymmetric catalysis, the catalytic asymmetric synthesis of fully substituted ones (tetrasubstituted allenes) remained largely an unsolved issue. The fundamental obstacle to solving this conundrum is the lack of a simple synthetic transformation that provides tetrasubstituted allenes in the action of catalysis. We report herein a strategy to overcome this issue by the use of a phase-transfer-catalysed asymmetric functionalization of 1-alkylallene-1,3-dicarboxylates with N-arylsulfonyl imines and benzylic and allylic bromides.

  17. Asymmetric spindle pole formation in CPAP-depleted mitotic cells.

    Science.gov (United States)

    Lee, Miseon; Chang, Jaerak; Chang, Sunghoe; Lee, Kyung S; Rhee, Kunsoo

    2014-02-21

    CPAP is an essential component for centriole formation. Here, we report that CPAP is also critical for symmetric spindle pole formation during mitosis. We observed that pericentriolar material between the mitotic spindle poles were asymmetrically distributed in CPAP-depleted cells even with intact numbers of centrioles. The length of procentrioles was slightly reduced by CPAP depletion, but the length of mother centrioles was not affected. Surprisingly, the young mother centrioles of the CPAP-depleted cells are not fully matured, as evidenced by the absence of distal and subdistal appendage proteins. We propose that the selective absence of centriolar appendages at the young mother centrioles may be responsible for asymmetric spindle pole formation in CPAP-depleted cells. Our results suggest that the neural stem cells with CPAP mutations might form asymmetric spindle poles, which results in premature initiation of differentiation.

  18. Characteristic of involute slope modification of asymmetric spur gear

    Institute of Scientific and Technical Information of China (English)

    DENG Xiao-he; HUA Lin; HAN Xing-hui

    2015-01-01

    The meshing characteristic of asymmetric involute spur gear was studied, the equations of the geometric shape of the asymmetric gear for both sides were deduced, and the equations of contact ratio and the key points of contact were also obtained. Meanwhile, an involute slope modification method considering the effects of static transmission errors was proposed based on the meshing properties. The characteristic of the involute slope modification was analyzed by changing different modification parameters. The mesh stiffness and synthetic mesh stiffness of unmodified and modified asymmetric spur gears were investigated. Furthermore, the spectrums of synthetic mesh stiffness under different modification parameters were compared. Research results showed that the modification parameters influence the meshing performance of gear pairs, and the proposed modification method was feasible to improve the transmission performance of gear pairs with appropriate modification parameters.

  19. Continuous Flavor Symmetries and the Stability of Asymmetric Dark Matter

    CERN Document Server

    Bishara, Fady

    2014-01-01

    Generically, the asymmetric interactions in asymmetric dark matter (ADM) models lead to decaying DM. We show that, for ADM that carries nonzero baryon number, the continuous flavor symmetries that generate the flavor structure in the quark sector also imply a looser lower bound on the mass scale of the asymmetric mediators between the dark and visible sectors. The mediators for $B=2$ ADM that can produce a signal in the future indirect dark matter searches can thus also be searched for at the LHC. For two examples of the mediator models, with either the MFV or Froggatt-Nielsen flavor breaking pattern, we derive the FCNC constraints and discuss the search strategies at the LHC.

  20. Asymmetric nanoparticle may go "active" at room temperature

    Science.gov (United States)

    Sheng, Nan; Tu, YuSong; Guo, Pan; Wan, RongZheng; Wang, ZuoWei; Fang, HaiPing

    2017-04-01

    Using molecular dynamics simulations, we show that an asymmetrically shaped nanoparticle in dilute solution possesses a spontaneously curved trajectory within a finite time interval, instead of the generally expected random walk. This unexpected dynamic behavior has a similarity to that of active matters, such as swimming bacteria, cells, or even fish, but is of a different physical origin. The key to the curved trajectory lies in the non-zero resultant force originated from the imbalance of the collision forces acted by surrounding solvent molecules on the asymmetrically shaped nanoparticle during its orientation regulation. Theoretical formulae based on microscopic observations have been derived to describe this non-zero force and the resulting motion of the asymmetrically shaped nanoparticle.