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Sample records for 1-leg hop test

  1. Design, testing, and performance of a hybrid micro vehicle---The Hopping Rotochute

    NASA Astrophysics Data System (ADS)

    Beyer, Eric W.

    The Hopping Rotochute is a new hybrid micro vehicle that has been developed to robustly explore environments with rough terrain while minimizing energy consumption over long periods of time. The device consists of a small coaxial rotor system housed inside a lightweight cage. The vehicle traverses an area by intermittently powering a small electric motor which drives the rotor system, allowing the vehicle to hop over obstacles of various shapes and sizes. A movable internal mass controls the direction of travel while the egg-like exterior shape and low mass center allows the vehicle to passively reorient itself to an upright attitude when in contact with the ground. This dissertation presents the design, fabrication, and testing of a radio-controlled Hopping Rotochute prototype as well as an analytical study of the flight performance of the device. The conceptual design iterations are first outlined which were driven by the mission and system requirements assigned to the vehicle. The aerodynamic, mechanical, and electrical design of a prototype is then described, based on the final conceptual design, with particular emphasis on the fundamental trades that must be negotiated for this type of hopping vehicle. The fabrication and testing of this prototype is detailed as well as experimental results obtained from a motion capture system. Basic flight performance of the prototype are reported which demonstrates that the Hopping Rotochute satisfies all appointed system requirements. A dynamic model of the Hopping Rotochute is also developed in this thesis and employed to predict the flight performance of the vehicle. The dynamic model includes aerodynamic loads from the body and rotor system as well as a soft contact model to estimate the forces and moments during ground contact. The experimental methods used to estimate the dynamic model parameters are described while comparisons between measured and simulated motion are presented. Good correlation between these motions

  2. Hopping robot

    DOEpatents

    Spletzer, Barry L.; Fischer, Gary J.; Marron, Lisa C.; Martinez, Michael A.; Kuehl, Michael A.; Feddema, John T.

    2001-01-01

    The present invention provides a hopping robot that includes a misfire tolerant linear actuator suitable for long trips, low energy steering and control, reliable low energy righting, miniature low energy fuel control. The present invention provides a robot with hopping mobility, capable of traversing obstacles significant in size relative to the robot and capable of operation on unpredictable terrain over long range. The present invention further provides a hopping robot with misfire-tolerant combustion actuation, and with combustion actuation suitable for use in oxygen-poor environments.

  3. Hop Shoot Proliferation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop shoot proliferation disease has been described in Poland., and is associated with phytoplasma infection. Hop shoot proliferation occurs rarely and seems to be of little economic concern in most regions of hop production. Hop shoot proliferation is thought to be caused by aster yellows phytoplas...

  4. COMPARISON OF RANGE OF MOTION, STRENGTH, AND HOP TEST PERFORMANCE OF DANCERS WITH AND WITHOUT A CLINICAL DIAGNOSIS OF FEMOROACETABULAR IMPINGEMENT

    PubMed Central

    Carcia, Christopher R.; Christoforetti, John J.; Martin, RobRoy L.

    2016-01-01

    ABSTRACT Background Dancers commonly experience anterior hip pain caused by femoroacetabular impingement (FAI) that interrupts training and performance in dance. A paucity of literature exists to guide appropriate evaluation and management of FAI among dancers. Purpose The purpose of this study was to determine if dancers with clinical signs of FAI have differences in hip range of motion, strength, and hop test performance compared to healthy dancers. Study Design Quasi-experimental, cohort comparison. Methods Fifteen dancers aged between 18- 21 years with clinical signs of FAI that included anterior hip pain and provocative impingement tests were compared to 13 age-matched dancers for passive hip joint range of motion, isometric hip strength, and performance of the medial triple hop, lateral triple hop, and cross-over hop tests. Results No statistically significant differences in range of motion were noted for flexion (Healthy = 145° + 7°; FAI = 147° + 10°; p=0.59), internal rotation (Healthy = 63° + 7°; FAI = 61° + 11°; p=0.50), and external rotation (Healthy = 37° + 9°; FAI = 34° + 12°; p=0.68) between the two groups. Hip extension strength was significantly less in the dancers with FAI (224 + 55 Newtons) compared to the healthy group (293 ± 58 Newtons; F(1,26) = 10.2; p=0.004). No statistically significant differences were noted for flexion, internal rotation, external rotation, abduction, or adduction isometric strength. The medial triple hop test was significantly less in the FAI group (354 ± 43 cm) compared to the healthy group (410 ± 50 cm; F(1,26) = 10.3; p = 0.004). Similar results were observed for the lateral hop test, as the FAI group (294 ± 38 cm) performed worse than the healthy controls (344 ± 54cm; F(1,26) = 7.8; p = 0.01). There was no statistically significant difference between the FAI group (2.7 ± 0.92 seconds) and the healthy

  5. Propulsion phase of the single leg triple hop test in women with patellofemoral pain syndrome: a biomechanical study.

    PubMed

    Bley, Andre Serra; Correa, João Carlos Ferrari; Dos Reis, Amir Curcio; Rabelo, Nayra Deise Dos Anjos; Marchetti, Paulo Henrique; Lucareli, Paulo Roberto Garcia

    2014-01-01

    Asymmetry in the alignment of the lower limbs during weight-bearing activities is associated with patellofemoral pain syndrome (PFPS), caused by an increase in patellofemoral (PF) joint stress. High neuromuscular demands are placed on the lower limb during the propulsion phase of the single leg triple hop test (SLTHT), which may influence biomechanical behavior. The aim of the present cross-sectional study was to compare kinematic, kinetic and muscle activity in the trunk and lower limb during propulsion in the SLTHT using women with PFPS and pain free controls. The following measurements were made using 20 women with PFPS and 20 controls during propulsion in the SLTHT: kinematics of the trunk, pelvis, hip, and knee; kinetics of the hip, knee and ankle; and muscle activation of the gluteus maximus (GM), gluteus medius (GMed), biceps femoris (BF) and vastus lateralis (VL). Differences between groups were calculated using three separate sets of multivariate analysis of variance for kinematics, kinetics, and electromyographic data. Women with PFPS exhibited ipsilateral trunk lean; greater trunk flexion; greater contralateral pelvic drop; greater hip adduction and internal rotation; greater ankle pronation; greater internal hip abductor and ankle supinator moments; lower internal hip, knee and ankle extensor moments; and greater GM, GMed, BL, and VL muscle activity. The results of the present study are related to abnormal movement patterns in women with PFPS. We speculated that these findings constitute strategies to control a deficient dynamic alignment of the trunk and lower limb and to avoid PF pain. However, the greater BF and VL activity and the extensor pattern found for the hip, knee, and ankle of women with PFPS may contribute to increased PF stress. PMID:24830289

  6. HIP HOP for HIV Awareness: Using Hip Hop Culture to Promote Community-Level HIV Prevention

    ERIC Educational Resources Information Center

    Hill, Mandy J.; Hallmark, Camden J.; McNeese, Marlene; Blue, Nike; Ross, Michael W.

    2014-01-01

    The goal of this paper was to determine the effectiveness of the HIP HOP for HIV Awareness intervention, an innovative model utilising an exchange of an HIV test for a hip hop concert ticket, in a metropolitan city among African American youth and young adults. A subset of intervention participants participated in standardised testing, sex…

  7. Determinants of the abilities to jump higher and shorten the contact time in a running 1-legged vertical jump in basketball.

    PubMed

    Miura, Ken; Yamamoto, Masayoshi; Tamaki, Hiroyuki; Zushi, Koji

    2010-01-01

    This study was conducted to obtain useful information for developing training techniques for the running 1-legged vertical jump in basketball (lay-up shot jump). The ability to perform the lay-up shot jump and various basic jumps was measured by testing 19 male basketball players. The basic jumps consisted of the 1-legged repeated rebound jump, the 2-legged repeated rebound jump, and the countermovement jump. Jumping height, contact time, and jumping index (jumping height/contact time) were measured and calculated using a contact mat/computer system that recorded the contact and air times. The jumping index indicates power. No significant correlation existed between the jumping height and contact time of the lay-up shot jump, the 2 components of the lay-up shot jump index. As a result, jumping height and contact time were found to be mutually independent abilities. The relationships in contact time between the lay-up shot jump to the 1-legged repeated rebound jump and the 2-legged repeated rebound jump were correlated on the same significance levels (p < 0.05). A significant correlation for jumping height existed between the 1-legged repeated rebound jump and the lay-up shot jump (p < 0.05), although none existed for jumping height between the lay-up shot jump and both the 2-legged repeated rebound jump and countermovement jump. The lay-up shot index correlated more strongly to the 1-legged repeated rebound jump index (p < 0.01) when compared to the 2-legged repeated rebound jump index (p < 0.05). These results suggest that the 1-legged repeated rebound jump is effective in improving both contact time and jumping height in the lay-up shot jump. PMID:19996782

  8. Wheeled hopping robot

    SciTech Connect

    Fischer, Gary J.

    2010-08-17

    The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.

  9. Hopping Robot with Wheels

    NASA Technical Reports Server (NTRS)

    Barlow, Edward; Marzwell, Nevellie; Fuller, Sawyer; Fionni, Paolo; Tretton, Andy; Burdick, Joel; Schell, Steve

    2003-01-01

    A small prototype mobile robot is capable of (1) hopping to move rapidly or avoid obstacles and then (2) moving relatively slowly and precisely on the ground by use of wheels in the manner of previously reported exploratory robots of the "rover" type. This robot is a descendant of a more primitive hopping robot described in "Minimally Actuated Hopping Robot" (NPO- 20911), NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 50. There are many potential applications for robots with hopping and wheeled-locomotion (roving) capabilities in diverse fields of endeavor, including agriculture, search-and-rescue operations, general military operations, removal or safe detonation of land mines, inspection, law enforcement, and scientific exploration on Earth and remote planets. The combination of hopping and roving enables this robot to move rapidly over very rugged terrain, to overcome obstacles several times its height, and then to position itself precisely next to a desired target. Before a long hop, the robot aims itself in the desired hopping azimuth and at a desired takeoff angle above horizontal. The robot approaches the target through a series of hops and short driving operations utilizing the steering wheels for precise positioning.

  10. Hop Cultivars and Breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pest management decision making in hops varies among cultivars. Historically, the primary objective of hop breeding programs has been to increase the yield or characteristics associated with either bittering (high alpha-acids) or aroma (unique volatile oil profiles) cultivars. Other factors consid...

  11. Degradation of hop bitter acids by fungi

    SciTech Connect

    Huszcza, Ewa Bartmanska, Agnieszka; Aniol, Miroslaw; Maczka, Wanda; Zolnierczyk, Anna; Wawrzenczyk, Czeslaw

    2008-07-01

    Nine fungal strains related to: Trametes versicolor, Nigrospora oryzae, Inonotus radiatus, Crumenulopsis sororia, Coryneum betulinum, Cryptosporiopsis radicicola, Fusarium equiseti, Rhodotorula glutinis and Candida parapsilosis were tested for their ability to degrade humulones and lupulones. The best results were obtained for T. versicolor culture, in which humulones and lupulones were fully degraded after 4 days of incubation in the dark or after 36 h in the light. The experiments were performed on a commercial hop extract and on sterilized spent hops.

  12. The lunar hopping transporter

    NASA Technical Reports Server (NTRS)

    Degner, R.; Kaplan, M. H.; Manning, J.; Meetin, R.; Pasternack, S.; Peterson, S.; Seifert, H.

    1971-01-01

    Research on several aspects of lunar transport using the hopping mode is reported. Hopping exploits the weak lunar gravity, permits fuel economy because of partial recompression of propellant gas on landing, and does not require a continuous smooth surface for operation. Three questions critical to the design of a lunar hopping vehicle are addressed directly in this report: (1) the tolerance of a human pilot for repeated accelerations; (2) means for controlling vehicle attitude during ballistic flight; and (3) means of propulsion. In addition, a small scale terrestrial demonstrator built to confirm feasibility of the proposed operational mode is described, along with results of preliminary study of unmanned hoppers for moon exploration.

  13. Surface Hopping by Consensus.

    PubMed

    Martens, Craig C

    2016-07-01

    We present a new stochastic surface hopping method for modeling molecular dynamics with electronic transitions. The approach, consensus surface hopping (CSH), is a numerical framework for solving the semiclassical limit Liouville equation describing nuclear dynamics on coupled electronic surfaces using ensembles of trajectories. In contrast to existing techniques based on propagating independent classical trajectories that undergo stochastic hops between the electronic states, the present method determines the probabilities of transition of each trajectory collectively with input from the entire ensemble. The full coherent dynamics of the coupled system arise naturally at the ensemble level and ad hoc corrections, such as momentum rescaling to impose strict trajectory energy conservation and artificial decoherence to avoid the overcoherence of the quantum states associated with independent trajectories, are avoided. PMID:27345103

  14. GENERAL VIEW OF SITE LOOKING SOUTHWEST. JUPITER 'HOP' STAND, FOREGROUND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL VIEW OF SITE LOOKING SOUTHWEST. JUPITER 'HOP' STAND, FOREGROUND CENTER, REDSTONE TEST STAND FOREGROUND RIGHT, SATURN I C TEST STAND BACKGROUND LEFT. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  15. Registration of 'Teamaker' Hop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Teamaker' is a new hop (Humulus lupulus L.) variety exhibiting high beta-acids and near-zero alpha acids soft resins contents, a unique situation in the Humulus species. Teamaker arose as a selection from the cross, USDA 19105 x USDA 19046M, and as such has the genetic composition of 5/16th Fuggle...

  16. Homeobox Protein Hop Functions in the Adult Cardiac Conduction System

    PubMed Central

    Ismat, Fraz A.; Zhang, Maozhen; Kook, Hyun; Huang, Bin; Zhou, Rong; Ferrari, Victor A.; Epstein, Jonathan A.; Patel, Vickas V.

    2006-01-01

    Hop is an unusual homeobox gene expressed in the embryonic and adult heart. Hop acts downstream of Nkx2–5 during development, and Nkx2–5 mutations are associated with cardiac conduction system (CCS) defects. Inactivation of Hop in the mouse is lethal in half of the expected null embryos. Here, we show that Hop is expressed strongly in the adult CCS. Hop−/− adult mice display conduction defects below the atrioventricular node (AVN) as determined by invasive electrophysiological testing. These defects are associated with decreased expression of connexin40. Our results suggest that Hop functions in the adult CCS and demonstrate conservation of molecular hierarchies between embryonic myocardium and the specialized conduction tissue of the mature heart. PMID:15790958

  17. Hip-Hop Education Resources

    ERIC Educational Resources Information Center

    Hall, Marcella Runell

    2009-01-01

    Hip-hop music and culture are often cited as being public pedagogy, meaning the music itself has intrinsic educational value. Non-profit organizations and individual educators have graciously taken the lead in utilizing hip-hop to educate. As the academy continues to debate its effectiveness, teachers and community organizers are moving forward.…

  18. Reliable and efficient hop-by-hop flow control

    NASA Astrophysics Data System (ADS)

    Ozveren, Cuneyt M.; Simcoe, Robert; Varghese, George

    1995-05-01

    Hop-by-hop flow control can be used to fairly share the bandwidth of a network among competing flows. No data is lost even in overload conditions; yet each flow gets access to the maximum throughput when the network is lightly loaded. However, some schemes for hop-by-hop flow control require too much memory; some of them are not resilient to errors. We propose a scheme for making hop-by-hop flow control resilient and show that it has advantages over the first several schemes proposed by Kung. We also describe a novel method for sharing the available buffers among the flows on a link; our scheme allows us to potentially reduce the memory requirement (or increase the number of flows that can be supported) by an order of magnitude. Most of the work is described in the context of an ATM network that uses credit-based flow control. However, our ideas extend to networks in which flows can be distinguished, and to rate-based flow control schemes.

  19. Star-Hopping

    NASA Astrophysics Data System (ADS)

    Garfinkle, Robert A.

    1997-07-01

    Introduction; Preface; Acknowledgements; 1. How to use this book and what you are going to see; 2. How the sky works, determining your field of view, observing tips and how to navigate in the night sky; 3. January - Taurus and Orion: the bull and hunter; 4. February - Canis Minor, Canis Major, and Puppis: dog days in February and Jason's Argo; 5. March - Cancer, Leo, and Corvus: a crab, the king of the beasts, and a crow; 6. April - Ursa Major: a dipper round tripper; 7. May - Coma Berenices and Virgo: the sparkling hair of Berenice and the wheat maiden and her bushel of galaxies; 8. June - Libra and Lupus: the balance scales and the wolf; 9. July - Scorpius, Sagittarius, and Scutum: the scorpion, archer, and shield of John Sobieski; 10. August - Draco: following the trail of the dragon; 11. September - Cygnus, Lyra, Vulpecula, and Sagitta: the swan, lyre, fox, and arrow; 12. October - Andromeda and Perseus: the chained lady and her rescuer; 13. November - Cepheus and Cassiopeia: the king and queen of Joppa; 14. December - Pisces, Triangulum, and Aries: of fishes, a triangle, and a ram; 15. Messier Marathon, a sundown to sunup hop across the skies; Appendix A: Classification tables; Appendix B: The constellations; Appendix C: The Greek alphabet; Appendix D: Decimalization of the day; Glossary; Bibliography; Index.

  20. Extreme Kinematics in Selected Hip Hop Dance Sequences.

    PubMed

    Bronner, Shaw; Ojofeitimi, Sheyi; Woo, Helen

    2015-09-01

    Hip hop dance has many styles including breakdance (breaking), house, popping and locking, funk, streetdance, krumping, Memphis jookin', and voguing. These movements combine the complexity of dance choreography with the challenges of gymnastics and acrobatic movements. Despite high injury rates in hip hop dance, particularly in breakdance, to date there are no published biomechanical studies in this population. The purpose of this study was to compare representative hip hop steps found in breakdance (toprock and breaking) and house and provide descriptive statistics of the angular displacements that occurred in these sequences. Six expert female hip hop dancers performed three choreographed dance sequences, top rock, breaking, and house, to standardized music-based tempos. Hip, knee, and ankle kinematics were collected during sequences that were 18 to 30 sec long. Hip, knee, and ankle three-dimensional peak joint angles were compared in repeated measures ANOVAs with post hoc tests where appropriate (p<0.01). Peak angles of the breaking sequence, which included floorwork, exceeded the other two sequences in the majority of planes and joints. Hip hop maximal joint angles exceeded reported activities of daily living and high injury sports such as gymnastics. Hip hop dancers work at weight-bearing joint end ranges where muscles are at a functional disadvantage. These results may explain why lower extremity injury rates are high in this population. PMID:26395613

  1. Signaling induced by hop/STI-1 depends on endocytosis

    SciTech Connect

    Americo, Tatiana A.; Chiarini, Luciana B.; Linden, Rafael . E-mail: rlinden@biof.ufrj.br

    2007-06-29

    The co-chaperone hop/STI-1 is a ligand of the cell surface prion protein (PrP{sup C}), and their interaction leads to signaling and biological effects. Among these, hop/STI-1 induces proliferation of A172 glioblastoma cells, dependent on both PrP{sup C} and activation of the Erk pathway. We tested whether clathrin-mediated endocytosis affects signaling induced by hop/STI-1. Both hyperosmolarity induced by sucrose and monodansyl-cadaverine blocked Erk activity induced by hop/STI-1, without affecting the high basal Akt activity typical of A172. The endocytosis inhibitors also affected the sub-cellular distribution of phosphorylated Erk, consistent with blockade of the latter's activity. The data indicate that signaling induced by hop/STI-1 depends on endocytosis. These findings are consistent with a role of sub-cellular trafficking in signal transduction following engagement by PrP{sup C} by ligands such as hop/STI-1, and may help help unravel both the functions of the prion protein, as well as possible loss-of-function components of prion diseases.

  2. Hop extracts and hop substances in treatment of menopausal complaints.

    PubMed

    Keiler, Annekathrin M; Zierau, Oliver; Kretzschmar, Georg

    2013-05-01

    Hop extract is a long used medicinal product and, regarding hormonal activities, in 1999 a number of prenylflavanones have been identified as its major constituents with 8-prenylnaringenin (8-PN) being the main active estrogenic compound. There have been several in vivo studies performed that demonstrate the potential of hop extract and the single compound 8-PN to alleviate climacteric symptoms like osteoporosis, vasomotoric complaints, and sexual motivation. On the other hand, only a few clinical studies have been performed so far, and these mainly focused on menopausal discomforts, especially hot flushes, yielding rather inconclusive results. Despite preferentially activating estrogen receptor α, 8-PN is only slightly uterotrophic, but it also elucidates estrogenic effects on the mammary gland. In conclusion, although hop extract and especially 8-PN are promising candidates as a relief for climacteric symptoms, data on the safety and efficacy is still scarce. PMID:23512496

  3. Optimization of conditions for supercritical fluid extraction of flavonoids from hops (Humulus lupulus L.).

    PubMed

    He, Guo-Qing; Xiong, Hao-Ping; Chen, Qi-He; Ruan, Hui; Wang, Zhao-Yue; Traoré, Lonseny

    2005-10-01

    Waste hops are good sources of flavonoids. Extraction of flavonoids from waste hops (SC-CO(2) extracted hops) using supercritical fluids technology was investigated. Various temperatures, pressures and concentrations of ethanol (modifier) and the ratio (w/w) of solvent to material were tested in this study. The results of single factor and orthogonal experiments showed that at 50 degrees C, 25 MPa, the ratio of solvent to material (50%), ethanol concentration (80%) resulted in maximum extraction yield flavonoids (7.8 mg/g). HPLC-MS analysis of the extracts indicated that flavonoids obtained were xanthohumol, the principal prenylflavonoid in hops. PMID:16187413

  4. Hip-Hop and the Academic Canon

    ERIC Educational Resources Information Center

    Abe, Daudi

    2009-01-01

    Over the last 30 years, the hip-hop movement has risen from the margins to become the preeminent force in US popular culture. In more recent times academics have begun to harness the power of hip-hop culture and use it as a means of infusing transformative knowledge into the mainstream academic discourse. On many college campuses, hip-hop's…

  5. Hip-Hop Pop Art

    ERIC Educational Resources Information Center

    Talley, Clarence, Sr.

    2011-01-01

    Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate…

  6. Long range hopping mobility platform.

    SciTech Connect

    Spletzer, Barry Louis; Fischer, Gary John

    2003-03-01

    Sandia National Laboratories has developed a mesoscale hopping mobility platform (Hopper) to overcome the longstanding problems of mobility and power in small scale unmanned vehicles. The system provides mobility in situations such as negotiating tall obstacles and rough terrain that are prohibitive for other small ground base vehicles. The Defense Advanced Research Projects Administration (DARPA) provided the funding for the hopper project.

  7. A novel approach for identification of biologically active phenolic compounds in complex matrices using hybrid quadrupole-orbitrap mass spectrometer: A promising tool for testing antimicrobial activity of hops.

    PubMed

    Dušek, Martin; Jandovská, Vladimíra; Čermák, Pavel; Mikyška, Alexandr; Olšovská, Jana

    2016-08-15

    The phenolic compounds, secondary metabolites of hops represent a large family of compounds that could be subsequently divided into smaller groups based on the similarities between their chemical structures. The antibacterial, antifungal and antiviral properties of hops are well known, but there is a lack of information about antimicrobial activities of individual hop compounds. This study was carried out with an objective to identify compounds present in hops that have potential antibacterial activity. In the first stage of experiment, the active compounds with potential anti-microbial activity had to be extracted from hop cones. Therefore, minced hop cones were applied on solid growth medium inoculated with Staphylococcus aureus. The active substances that migrated into the medium created an inhibition zone. In the second stage of experiment, the inhibition zones were cut out from Petri dishes, active compounds were extracted from these zones and consequently analyzed using LC-HRMS. These complex assays were developed and optimized. The data were acquired by using a quadrupole-orbitrap hybrid mass spectrometer by targeted-MS2 experiment in both ionization modes. The MS method has been developed as a screening method with a subsequent fragmentation of compound of interest on the base of inclusion mass list. The unknown compounds extracted from inhibition zones have been identified either by searching against a database or their structure has been elucidated on the basis of their fragmentation spectra. On the basis of this experiment the list of active compounds with potential anti-microbial activities was enhanced. PMID:27260455

  8. Hall effect in hopping regime

    NASA Astrophysics Data System (ADS)

    Avdonin, A.; Skupiński, P.; Grasza, K.

    2016-02-01

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO.

  9. The biomechanics of vertical hopping: a review.

    PubMed

    Lamontagne, Mario; Kennedy, Matthew J

    2013-01-01

    Repetitive vertical hopping is a simple and relatively controlled task useful for studying basic neuromuscular properties and tissue mechanics. However, several biomechanical and physiological factors are involved. This article provides an overview of muscle and tendon properties and how these interact during vertical hopping. Muscle properties discussed are force-velocity and force-length relationships, electromechanical delay, muscle fiber type, stretch induced contraction amplification, and muscle spindle afferent feedback. Tendon properties include storage and reuse of elastic energy, tendon stiffness, afferent information from Golgi tendon organs, and failure points. These muscle and tendon properties interact to generate vertical hopping force and power. In addition to these basic properties, there are other more complicated factors to consider when analyzing vertical hopping such as balance and coordination. A wealth of information can be gathered by studying vertical hopping. Caution should be taken, however, to prevent inappropriate conclusions being drawn about hop performance due to oversimplification. PMID:24067123

  10. Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields.

    PubMed

    Piraneo, Tara G; Bull, Jon; Morales, Mariany A; Lavine, Laura C; Walsh, Douglas B; Zhu, Fang

    2015-01-01

    The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies. PMID:26621458

  11. Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields

    PubMed Central

    Piraneo, Tara G.; Bull, Jon; Morales, Mariany A.; Lavine, Laura C.; Walsh, Douglas B.; Zhu, Fang

    2015-01-01

    The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies. PMID:26621458

  12. Cover Story: The Miseducation of Hip-Hop.

    ERIC Educational Resources Information Center

    Evelyn, Jamilah

    2000-01-01

    Some higher education officials believe that hip-hop music is eating away at the morals, and ultimately the classroom experience, of today's college students. Discusses why the gap exists between student and faculty attitudes toward hip-hop, how hip-hop music represents blackness, how people perceive hip-hop youth, the positive side of hip-hop,…

  13. Complete Genome Sequence of a Hop Latent Virus Infecting Hop Plants

    PubMed Central

    Jo, Yeonhwa; Choi, Hoseong

    2015-01-01

    The hop latent virus is a single-stranded RNA virus that mainly infects hop plants. Here, we report the complete genome sequence of a hop latent virus, which was de novo assembled by RNA sequencing (RNA-seq). Our study indicates that transcriptome data are useful for identifying a complete viral genome. PMID:25908127

  14. Grand and Semigrand Canonical Basin-Hopping

    PubMed Central

    2015-01-01

    We introduce grand and semigrand canonical global optimization approaches using basin-hopping with an acceptance criterion based on the local contribution of each potential energy minimum to the (semi)grand potential. The method is tested using local harmonic vibrational densities of states for atomic clusters as a function of temperature and chemical potential. The predicted global minima switch from dissociated states to clusters for larger values of the chemical potential and lower temperatures, in agreement with the predictions of a model fitted to heat capacity data for selected clusters. Semigrand canonical optimization allows us to identify particularly stable compositions in multicomponent nanoalloys as a function of increasing temperature, whereas the grand canonical potential can produce a useful survey of favorable structures as a byproduct of the global optimization search. PMID:26669731

  15. Hops

    MedlinePlus

    ... health provider.Medications changed by the liver (Cytochrome P450 1A1 (CYP1A1) substrates)Some medications are changed and ... health provider.Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)Some medications are changed and ...

  16. Hops

    MedlinePlus

    ... changed by the liver (Cytochrome P450 1A1 (CYP1A1) substrates)Some medications are changed and broken down by ... changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)Some medications are changed and broken down by ...

  17. How Does a Hopping Kangaroo Breathe?

    ERIC Educational Resources Information Center

    Giuliodori, Mauricio J.; Lujan, Heidi L.; Janbaih, Hussein; DiCarlo, Stephen E.

    2010-01-01

    We developed a model to demonstrate how a hopping kangaroo breathes. Interestingly, a kangaroo uses less energy to breathe while hopping than while standing still. This occurs, in part, because rather than using muscle power to move air into and out of the lungs, air is pulled into (inspiration) and pushed out of (expiration) the lungs as the…

  18. Compendium of Hop Diseases and Pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This compendium of diseases, pests and other disorders of hop (Humulus lupulus L.) is designed to be a practical reference for anyone interested in growing hops, whether for commercial production, ornamental or home use. Growers, crop advisors, private consultants, home brewers, students, extension...

  19. Small polaron hopping transport along DNA molecules

    NASA Astrophysics Data System (ADS)

    Triberis, G. P.; Simserides, C.; Karavolas, V. C.

    2005-05-01

    We present a small polaron hopping model for interpreting the strong temperature (T) dependence of the electrical conductivity, σ, observed at high (h) temperatures along DNA molecules. The model takes into account the one-dimensional character of the system and the presence of disorder in the DNA double helix. Percolation-theoretical considerations lead to analytical expressions for the high temperature multiphonon-assisted small polaron hopping conductivity, the hopping distance and their temperature dependence. The experimental data for lambda phage DNA (λ-DNA) and poly(dA)-poly(dT) DNA follow nicely the theoretically predicted behaviour (lnσh~T-2/3). Moreover, our model leads to realistic values of the maximum hopping distances, supporting the idea of multiphonon-assisted hopping of small polarons between next nearest neighbours of the DNA molecular 'wire'. The low temperature case is also investigated.

  20. On transition rates in surface hopping

    NASA Astrophysics Data System (ADS)

    Escartín, J. M.; Romaniello, P.; Stella, L.; Reinhard, P.-G.; Suraud, E.

    2012-12-01

    Trajectory surface hopping (TSH) is one of the most widely used quantum-classical algorithms for nonadiabatic molecular dynamics. Despite its empirical effectiveness and popularity, a rigorous derivation of TSH as the classical limit of a combined quantum electron-nuclear dynamics is still missing. In this work, we aim to elucidate the theoretical basis for the widely used hopping rules. Naturally, we concentrate thereby on the formal aspects of the TSH. Using a Gaussian wave packet limit, we derive the transition rates governing the hopping process at a simple avoided level crossing. In this derivation, which gives insight into the physics underlying the hopping process, some essential features of the standard TSH algorithm are retrieved, namely (i) non-zero electronic transition rate ("hopping probability") at avoided crossings; (ii) rescaling of the nuclear velocities to conserve total energy; (iii) electronic transition rates linear in the nonadiabatic coupling vectors. The well-known Landau-Zener model is then used for illustration.

  1. Standardization of Weed Pollen Extracts, Japanese Hop and Mugwort, in Korea

    PubMed Central

    Jeong, Kyoung Yong; Son, Mina; Choi, Soo-Young; Park, Kyung Hee; Park, Hye Jung; Hong, Chein-Soo; Lee, Jae-Hyun

    2016-01-01

    Purpose Japanese hop (Humulus spp.) and mugwort (Artemisia spp.) are notable causes of autumn pollinosis in East Asia. However, Japanese hop and mugwort pollen extracts, which are widely used for the diagnosis, have not been standardized. This study was performed to standardize Japanese hop and mugwort pollen extracts. Materials and Methods Allergen extracts were prepared in a standardized way using locally collected Humulus japonicus and purchased Artemisia vulgaris pollens. The immunoglobulin E (IgE) reactivities of prepared extracts were compared with commercial extracts via IgE immunoblotting and inhibition analyses. Intradermal skin tests were performed to determine the bioequivalent allergy unit (BAU). Results The IgE reactive components of the extracts via IgE immunoblotting were similar to those of commercial extracts. A 11-kDa allergen showed the strongest IgE reactivity in Japanese hop, as did a 28-kDa allergen in mugwort pollen extracts. Allergenic potencies of the investigatory Japanese hop and mugwort extracts were essentially indistinguishable from the commercial ones. Sums of erythema of 50 mm by the intradermal skin test (ΣED50) were calculated to be 14.4th and 13.6th three-fold dilutions for Japanese hop and mugwort extracts, respectively. Therefore, the allergenic activity of the prepared extracts was 90827.4 BAU/mg for Japanese hop and 34412 BAU/mg for mugwort. Conclusion We produced Japanese hop and mugwort pollen extracts using a standardized method. Standardized Japanese hop and mugwort pollen extracts will facilitate the production of improved diagnostic and immunotherapeutic reagents. PMID:26847293

  2. High-throughput genotyping of hop (Humulus lupulus L.) utilising diversity arrays technology (DArT).

    PubMed

    Howard, E L; Whittock, S P; Jakše, J; Carling, J; Matthews, P D; Probasco, G; Henning, J A; Darby, P; Cerenak, A; Javornik, B; Kilian, A; Koutoulis, A

    2011-05-01

    Implementation of molecular methods in hop (Humulus lupulus L.) breeding is dependent on the availability of sizeable numbers of polymorphic markers and a comprehensive understanding of genetic variation. However, use of molecular marker technology is limited due to expense, time inefficiency, laborious methodology and dependence on DNA sequence information. Diversity arrays technology (DArT) is a high-throughput cost-effective method for the discovery of large numbers of quality polymorphic markers without reliance on DNA sequence information. This study is the first to utilise DArT for hop genotyping, identifying 730 polymorphic markers from 92 hop accessions. The marker quality was high and similar to the quality of DArT markers previously generated for other species; although percentage polymorphism and polymorphism information content (PIC) were lower than in previous studies deploying other marker systems in hop. Genetic relationships in hop illustrated by DArT in this study coincide with knowledge generated using alternate methods. Several statistical analyses separated the hop accessions into genetically differentiated North American and European groupings, with hybrids between the two groups clearly distinguishable. Levels of genetic diversity were similar in the North American and European groups, but higher in the hybrid group. The markers produced from this time and cost-efficient genotyping tool will be a valuable resource for numerous applications in hop breeding and genetics studies, such as mapping, marker-assisted selection, genetic identity testing, guidance in the maintenance of genetic diversity and the directed breeding of superior cultivars. PMID:21243330

  3. The effects of beta acids from hops (Humulus lupulus L.)on mortality of Varroa destructor (Acari: Varroidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beta acids from hop plants (Humulus lupulus L.) reduce feeding and oviposition behaviors and increase mortality in certain phytophagous mites. These compounds were tested for their effects on Varroa destructor (Anderson and Trueman) mortality. The effects of hops beta acids (HBA) on honey bee (Apis ...

  4. Steerable Hopping Six-Legged Robot

    NASA Technical Reports Server (NTRS)

    Younse, Paulo; Aghazarian, Hrand

    2010-01-01

    The figure depicts selected aspects of a six-legged robot that moves by hopping and that can be steered in the sense that it can be launched into a hop in a controllable direction. This is a prototype of hopping robots being developed for use in scientific exploration of rough terrain on remote planets that have surface gravitation less than that of Earth. Hopping robots could also be used on Earth, albeit at diminished hopping distances associated with the greater Earth gravitation. The upper end of each leg is connected through two universal joints to an upper and a lower hexagonal frame, such that the tilt of the leg depends on the relative position of the two frames. Two non-back-driveable worm-gear motor drives are used to control the relative position of the two frames along two axes 120 apart, thereby controlling the common tilt of all six legs and thereby, further, controlling the direction of hopping. Each leg includes an upper and a lower aluminum frame segment with a joint between them. A fiberglass spring, connected via hinges to both segments, is used to store hopping energy prior to launch into a hop and to cushion the landing at the end of the hop. A cable for loading the spring is run into each leg through the center of the universal joints and then down along the center lines of the segments to the lower end of the leg. A central spool actuated by a motor with a harmonic drive and an electromagnetic clutch winds in all six cables to compress all six springs (thereby also flexing all six legs) simultaneously. To ensure that all the legs push off and land in the same direction, timing- belt pulley drives are attached to the leg segments, restricting the flexing and extension of all six legs to a common linear motion. In preparation for a hop, the spool can be driven to load the spring legs by an amount corresponding to a desired hop distance within range. The amount of compression can be computed from the reading of a shaft-angle encoder that

  5. Dielectric relaxation and hopping conduction in reduced graphite oxide

    NASA Astrophysics Data System (ADS)

    Wei, Guidan; Yu, Ji; Gu, Min; Tang, Tong B.

    2016-06-01

    Graphite oxide reduced by sodium borohydride was characterised and its electrical conduction investigated with impedance spectroscopy. Thermal dependence of electrical modulus (instead of permittivity, its inverse) was calculated from complex impedance spectra, an approach that prevents any peak in dielectric loss (imaginary component) from being swarmed by large dc conductivity. Two loss peaks appeared at each tested frequency, in a sample of either degree of reduction. The set of weaker peak should arise from the relaxation of some polar bonds, as proposed earlier by us. The stronger loss peaks may correspond to the hopping of conduction electrons; variable range hopping is also consistent with the observed thermal dependence of conductivity. However, nearer ambient temperature there is a change in mechanism, to band transport, with an activation energy of fairly similar values as derived from both loss peaks and conductivity.

  6. Linking the mechanics and energetics of hopping with elastic ankle exoskeletons.

    PubMed

    Farris, Dominic James; Sawicki, Gregory S

    2012-12-15

    The springlike mechanics of the human leg during bouncing gaits has inspired the design of passive assistive devices that use springs to aid locomotion. The purpose of this study was to test whether a passive spring-loaded ankle exoskeleton could reduce the mechanical and energetic demands of bilateral hopping on the musculoskeletal system. Joint level kinematics and kinetics were collected with electromyographic and metabolic energy consumption data for seven participants hopping at four frequencies (2.2, 2.5, 2.8, and 3.2 Hz). Hopping was performed without an exoskeleton; with an springless exoskeleton; and with a spring-loaded exoskeleton. Spring-loaded ankle exoskeletons reduced plantar flexor muscle activity and the biological contribution to ankle joint moment (15-25%) and average positive power (20-40%). They also facilitated reductions in metabolic power (15-20%) across frequencies from 2.2 to 2.8 Hz compared with hopping with a springless exoskeleton. Reductions in metabolic power compared with hopping with no exoskeleton were restricted to hopping at 2.5 Hz only (12%). These results highlighted the importance of reducing the rate of muscular force production and work to achieve metabolic reductions. They also highlighted the importance of assisting muscles acting at the knee joint. Exoskeleton designs may need to be tuned to optimize exoskeleton mass, spring stiffness, and spring slack length to achieve greater metabolic reductions. PMID:23065760

  7. The 1963 Hip-Hop Machine: Hip-Hop Pedagogy as Composition.

    ERIC Educational Resources Information Center

    Rice, Jeff

    2003-01-01

    Proposes an alternative invention strategy for research-based argumentative writing. Investigates the coincidental usage of the term "whatever" in hip-hop, theory, and composition studies. Presents a "whatever-pedagogy" identified as "hip-hop pedagogy," a writing practice that models itself after digital sampling's rhetorical strategy of…

  8. Performance evaluation of frequency-hopped spread spectrum multi-hop networks

    NASA Astrophysics Data System (ADS)

    Gluck, J. W.; Geraniotis, Evaggelos A.

    1988-11-01

    Primary and secondary multiple-access interference processes are characterized for multi-hop packet radio networks, in which users are assumed to be Poisson-distributed in the plane and to use frequency hopped spread-spectrum signaling with a receiver-oriented assignment of frequency-hopping patterns. The throughput per node and the average forward progress are then evaluated for frequency-hopped multi-hop networks that employ Random Forward Routing with fixed transmission radius (RFR) and most forward progress routing with fixed transmission radius (MFR). The optimal average number of neighbors and transmission radius are derived for these cases when Reed-Solomon forward-error-control coding with minimum distance decoding or binary convolutional coding with Viterbi decoding is employed.

  9. On transition rates in surface hopping.

    PubMed

    Escartín, J M; Romaniello, P; Stella, L; Reinhard, P-G; Suraud, E

    2012-12-21

    Trajectory surface hopping (TSH) is one of the most widely used quantum-classical algorithms for nonadiabatic molecular dynamics. Despite its empirical effectiveness and popularity, a rigorous derivation of TSH as the classical limit of a combined quantum electron-nuclear dynamics is still missing. In this work, we aim to elucidate the theoretical basis for the widely used hopping rules. Naturally, we concentrate thereby on the formal aspects of the TSH. Using a Gaussian wave packet limit, we derive the transition rates governing the hopping process at a simple avoided level crossing. In this derivation, which gives insight into the physics underlying the hopping process, some essential features of the standard TSH algorithm are retrieved, namely (i) non-zero electronic transition rate ("hopping probability") at avoided crossings; (ii) rescaling of the nuclear velocities to conserve total energy; (iii) electronic transition rates linear in the nonadiabatic coupling vectors. The well-known Landau-Zener model is then used for illustration. PMID:23267477

  10. Landau-Zener type surface hopping algorithms.

    PubMed

    Belyaev, Andrey K; Lasser, Caroline; Trigila, Giulio

    2014-06-14

    A class of surface hopping algorithms is studied comparing two recent Landau-Zener (LZ) formulas for the probability of nonadiabatic transitions. One of the formulas requires a diabatic representation of the potential matrix while the other one depends only on the adiabatic potential energy surfaces. For each classical trajectory, the nonadiabatic transitions take place only when the surface gap attains a local minimum. Numerical experiments are performed with deterministically branching trajectories and with probabilistic surface hopping. The deterministic and the probabilistic approach confirm the affinity of both the LZ probabilities, as well as the good approximation of the reference solution computed by solving the Schrödinger equation via a grid based pseudo-spectral method. Visualizations of position expectations and superimposed surface hopping trajectories with reference position densities illustrate the effective dynamics of the investigated algorithms. PMID:24929375

  11. Epigenetic Stability of Cryopreserved and Cold-Stored Hops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three hop accessions representative of commercially cultivated hops were selected for the analysis of epigenetic stability; females of different origins, including a cultivar developed in New Zealand (Calicross) from American cultivars, a landrace derived European cultivar (Tardif de Bourgogne), and...

  12. Leg stiffness adjustment during hopping at different intensities and frequencies.

    PubMed

    Mrdakovic, Vladimir; Ilic, Dusko; Vulovic, Radun; Matic, Milan; Jankovic, Nenad; Filipovic, Nenad

    2014-01-01

    Understanding leg and joint stiffness adjustment during maximum hopping may provide important information for developing more effective training methods. It has been reported that ankle stiffness has major influence on stable spring-mass dynamics during submaximal hopping, and that knee stiffness is a major determinant for hopping performance during maximal hopping task. Furthermore, there are no reports on how the height of the previous hop could affect overall stiffness modulation of the subsequent maximum one. The purpose of the present study was to determine whether and how the jump height of the previous hop affects leg and joint stiffness for subsequent maximum hop. Ten participants completed trials in which they repeatedly hopped as high as possible (MX task) and trials in which they were instructed to perform several maximum hops with 3 preferred (optimal) height hops between each of them (P3MX task). Both hopping tasks were performed at 2.2 Hz hopping frequency and at the participant's preferred (freely chosen) frequency as well. By comparing results of those hopping tasks, we found that ankle stiffness at 2.2 Hz ( p = 0.041) and knee stiffness at preferred frequency ( p = 0.045) was significantly greater for MX versus P3MX tasks. Leg stiffness for 2.2 Hz hopping is greater than for the preferred frequency. Ankle stiffness is greater for 2.2 Hz than for preferred frequencies; opposite stands for knee stiffness. The results of this study suggest that preparatory hop height can be considered as an important factor for modulation of maximum hop. PMID:25308379

  13. A Case Study: Significance, Epidemiology, and Management of Hop Viruses.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop latent carlavirus (HpLV), Hop mosaic carlavirus (HpMV), and Apple mosaic ilarvirus (ApMV) are viruses that have been shown to have deleterious effects on cone yield and brewing organic acids in several cultivars in Australian hop gardens, and pose a significant threat to the continued production...

  14. Revolutionizing Environmental Education through Indigenous Hip Hop Culture

    ERIC Educational Resources Information Center

    Gorlewski, Julie; Porfilio, Brad J.

    2012-01-01

    Based upon the life histories of six Indigenous hip hop artists of the Beat Nation artist collective, this essay captures how Indigenous hip hop has the potential to revolutionize environmental education. Hip hop provides Indigenous youth an emancipatory space to raise their opposition to neocolonial controls of Indigenous territories that…

  15. Hip-Hopping across China: Intercultural Formulations of Local Identities

    ERIC Educational Resources Information Center

    Barrett, Catrice

    2012-01-01

    The linguistic dimensions of globalized hip-hop cannot be understood simply as a byproduct of English as an American export. As hip-hop mobilizes, it is common (and arguably necessary) for global hip-hop communities to struggle through purposeful, semiotically rooted dialectics over what constitutes "authentic" and respectable forms of local…

  16. Genomics of the hop psuedo-autosomal regions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop is one of the few crop species with female and male plants with sex being determined by either XX or XY chromosomes. Hop cones are only produced in female hops with or without fertilization. This has lead to most genomic research being directed toward female plants. Very little work has been don...

  17. HPLC Analysis of [Alpha]- and [Beta]-Acids in Hops

    ERIC Educational Resources Information Center

    Danenhower, Travis M.; Force, Leyna J.; Petersen, Kenneth J.; Betts, Thomas A.; Baker, Gary A.

    2008-01-01

    Hops have been used for centuries to impart aroma and bitterness to beer. The cones of the female hop plant contain both essential oils, which include many of the fragrant components of hops, and a collection of compounds known as [alpha]- and [beta]-acids that are the precursors to bittering agents. In order for brewers to predict the ultimate…

  18. Suppression of Hop Looper (Lepidoptera: Noctuidae) by the fungicide Pyraclostrobin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The hop looper, Hypena humuli Harris, is a reemergent pest of hop that often requires treatment to mitigate crop damage. In four years of field trials, plots treated with fungicides were observed to sustain less hop looper defoliation as compared to nontreated plots. Further investigation revealed...

  19. Communication: Fully coherent quantum state hopping

    SciTech Connect

    Martens, Craig C.

    2015-10-14

    In this paper, we describe a new and fully coherent stochastic surface hopping method for simulating mixed quantum-classical systems. We illustrate the approach on the simple but unforgiving problem of quantum evolution of a two-state quantum system in the limit of unperturbed pure state dynamics and for dissipative evolution in the presence of both stationary and nonstationary random environments. We formulate our approach in the Liouville representation and describe the density matrix elements by ensembles of trajectories. Population dynamics are represented by stochastic surface hops for trajectories representing diagonal density matrix elements. These are combined with an unconventional coherent stochastic hopping algorithm for trajectories representing off-diagonal quantum coherences. The latter generalizes the binary (0,1) “probability” of a trajectory to be associated with a given state to allow integers that can be negative or greater than unity in magnitude. Unlike existing surface hopping methods, the dynamics of the ensembles are fully entangled, correctly capturing the coherent and nonlocal structure of quantum mechanics.

  20. The Rap on Hip-Hop

    ERIC Educational Resources Information Center

    Piekarski, Bill

    2004-01-01

    From its humble origins some 30 years ago in New York's bombed-out, poverty-ravaged South Bronx, hip-hop has risen to become a dominant cultural force both here and abroad. Strictly defined, the term refers to the entire cultural constellation that accompanies rap music, which in 2001 surpassed country music as the most popular musical genre in…

  1. Injury incidence in hip hop dance.

    PubMed

    Ojofeitimi, S; Bronner, S; Woo, H

    2012-06-01

    Hip hop dance has rapidly become a popular international art form. There is limited information on injury patterns in this population. The purpose of this study was to determine injury incidence and patterns among three groups of hip hop dancers. Three hundred and twelve intermediate, advanced, and expert hip hop dancers were recruited at battles, dance conferences, clubs, and on dance related web sites within the United States and internationally. A Web-based survey was conducted over a 6-month period. Inclusion criteria included intermediate and advanced level dancers over the age of 13. Dancers were divided into three main categories: Breakers, Popper/Lockers, and New Schoolers. Separate analysis of variances were used to compare injury pattern differences between groups. Two hundred and thirty-two dancers reported a total of 738 injuries. Five hundred and six of these (sustained by 205 dancers) were time-loss (TL) injuries. Annual injury incidence was 237% (162% involving TL). Lower extremity injuries were 52% and upper extremity injuries 32% of total injuries. Breakers had a higher injury incidence compared with Popper/Lockers, and New Schoolers. Hip hop dancers report injury rates that are higher than other dance forms but similar to gymnastics. These dancers should be educated concerning injury prevention, biomechanics, and use of protective equipment. PMID:20807386

  2. Multimodal Hip Hop Productions as Media Literacies

    ERIC Educational Resources Information Center

    Turner, K. C. Nat

    2012-01-01

    This study draws on ethnographic data from a year-long multimodal media production (MMP) course and the experience of an African American female adolescent who used the production of multimodal Hip Hop texts to express her creativity and growing socially conscious view of the world. The study demonstrates how students made meaning multimodally and…

  3. Forecasting and management of hop downy mildew

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Downy mildew of hop, caused by Pseudoperonospora humuli, is managed in the Pacific Northwestern U.S. by regular application of fungicides. A degree-day model that forecasts the first emergence of shoots systemically infection with P. humuli (termed basal spikes) and a risk index for secondary sprea...

  4. Communication: Fully coherent quantum state hopping

    NASA Astrophysics Data System (ADS)

    Martens, Craig C.

    2015-10-01

    In this paper, we describe a new and fully coherent stochastic surface hopping method for simulating mixed quantum-classical systems. We illustrate the approach on the simple but unforgiving problem of quantum evolution of a two-state quantum system in the limit of unperturbed pure state dynamics and for dissipative evolution in the presence of both stationary and nonstationary random environments. We formulate our approach in the Liouville representation and describe the density matrix elements by ensembles of trajectories. Population dynamics are represented by stochastic surface hops for trajectories representing diagonal density matrix elements. These are combined with an unconventional coherent stochastic hopping algorithm for trajectories representing off-diagonal quantum coherences. The latter generalizes the binary (0,1) "probability" of a trajectory to be associated with a given state to allow integers that can be negative or greater than unity in magnitude. Unlike existing surface hopping methods, the dynamics of the ensembles are fully entangled, correctly capturing the coherent and nonlocal structure of quantum mechanics.

  5. The Philippine "Hip Hop Stick Dance"

    ERIC Educational Resources Information Center

    Lewis, Lisa

    2012-01-01

    This article introduces a dance that blends the traditional cultural heritage of the Philippines with modern music and moves. "Hip Hop Stick Dance" incorporates Tinikling (the Philippine national dance) and Arnis (a Filipino style of martial arts) to create a contemporary combination of rhythm, dance, and fitness. It was designed to introduce…

  6. Hopping Diffusion of Nanoparticles in Polymer Matrices

    PubMed Central

    2016-01-01

    We propose a hopping mechanism for diffusion of large nonsticky nanoparticles subjected to topological constraints in both unentangled and entangled polymer solids (networks and gels) and entangled polymer liquids (melts and solutions). Probe particles with size larger than the mesh size ax of unentangled polymer networks or tube diameter ae of entangled polymer liquids are trapped by the network or entanglement cells. At long time scales, however, these particles can diffuse by overcoming free energy barrier between neighboring confinement cells. The terminal particle diffusion coefficient dominated by this hopping diffusion is appreciable for particles with size moderately larger than the network mesh size ax or tube diameter ae. Much larger particles in polymer solids will be permanently trapped by local network cells, whereas they can still move in polymer liquids by waiting for entanglement cells to rearrange on the relaxation time scales of these liquids. Hopping diffusion in entangled polymer liquids and networks has a weaker dependence on particle size than that in unentangled networks as entanglements can slide along chains under polymer deformation. The proposed novel hopping model enables understanding the motion of large nanoparticles in polymeric nanocomposites and the transport of nano drug carriers in complex biological gels such as mucus. PMID:25691803

  7. Inhibition of human cytochrome P450 enzymes by hops (Humulus lupulus) and hop prenylphenols

    PubMed Central

    Nikolić, Dejan; Chen, Shao-Nong; Huang, Ke; Li, Guannan; Pauli, Guido F.; van Breemen, Richard B.

    2014-01-01

    As hops (Humulus lupulus L.) are used in the brewing of beer and by menopausal women as estrogenic dietary supplements, the potential for hop extracts and hop constituents to cause drug-botanical interactions by inhibiting human cytochrome P450 enzymes was investigated. Inhibition of major human cytochrome P450 enzymes by a standardized hop extract and isolated hop prenylated phenols was evaluated using a fast and efficient assay based on ultrahigh pressure liquid chromatography-tandem mass spectrometry. The hop extract at 5 μg/mL inhibited CYP2C8 (93%), CYP2C9 (88%), CYP2C19 (70%), and CYP1A2 (27%) with IC50 values of 0.8, 0.9, 3.3, and 9.4 μg/mL, respectively, but time-dependent inactivation was observed only for CYP1A2. Isoxanthohumol from hops was the most potent inhibitor of CYP2C8 with an IC50 of 0.2 μM, whereas 8-prenylnaringenin was the most potent inhibitor of CYP1A2, CYP2C9 and CYP2C19 with IC50 values of 1.1 μM, 1.1 μM and 0.4 μM, respectively. Extracts of hops contain prenylated compounds such as the flavanones isoxanthohumol and 8-prenylnaringenin and the chalcone xanthohumol that can inhibit CYP450s, especially the CYP2C family, which may affect the efficacy and safety of some CYP2C substrate drugs when co-administered. PMID:24342125

  8. Inhibition of human cytochrome P450 enzymes by hops (Humulus lupulus) and hop prenylphenols.

    PubMed

    Yuan, Yang; Qiu, Xi; Nikolić, Dejan; Chen, Shao-Nong; Huang, Ke; Li, Guannan; Pauli, Guido F; van Breemen, Richard B

    2014-03-12

    As hops (Humulus lupulus L.) are used in the brewing of beer and by menopausal women as estrogenic dietary supplements, the potential for hop extracts and hop constituents to cause drug-botanical interactions by inhibiting human cytochrome P450 enzymes was investigated. Inhibition of major human cytochrome P450 enzymes by a standardized hop extract and isolated hop prenylated phenols was evaluated using a fast and efficient assay based on ultrahigh pressure liquid chromatography-tandem mass spectrometry. The hop extract at 5 μg/mL inhibited CYP2C8 (93%), CYP2C9 (88%), CYP2C19 (70%), and CYP1A2 (27%) with IC50 values of 0.8, 0.9, 3.3, and 9.4 μg/mL, respectively, but time-dependent inactivation was observed only for CYP1A2. Isoxanthohumol from hops was the most potent inhibitor of CYP2C8 with an IC50 of 0.2 μM, whereas 8-prenylnaringenin was the most potent inhibitor of CYP1A2, CYP2C9 and CYP2C19 with IC50 values of 1.1 μM, 1.1 μM and 0.4 μM, respectively. Extracts of hops contain prenylated compounds such as the flavanones isoxanthohumol and 8-prenylnaringenin and the chalcone xanthohumol that can inhibit CYP450s, especially the CYP2C family, which may affect the efficacy and safety of some CYP2C substrate drugs when co-administered. PMID:24342125

  9. HopRec: Hop-Based Recommendation Ability Enhanced Reputation Ranking in P2P Networks

    NASA Astrophysics Data System (ADS)

    Wang, Yufeng; Nakao, Akihiro; Ma, Jianhua

    As a concept stemmed from social field, we argued that, in P2P networks, peers' recommendation behaviors and functional behaviors should be explicitly separated, thus we propose the HopRec scheme which uses hop-based recommendation ability to improve the accuracy of reputation ranking in P2P networks. Our contributions lie in the following aspects: firstly, we adopt the simple but effective idea to infer peer's recommendation ability (RA): the farer away that peer is from the initial malicious seeds, the higher RA that peer should have; Then, the computation of reputation rankings appropriately reflects peer's different RA. The simulation results show that, in comparison with Eigentrust-like algorithms, HopRec can be robust to sybils and front peers attacks, and achieve significant performance improvement. Moreover, we compare HopRec with two related schemes, Poisonedwater and CredibleRank, and found that: in hospitable P2P environment, HopRec can obtain better performance than Poisonedwater, and can achieve the comparable performance as CredibleRank, with less computation overhead then CredibleRank. Finally, we also show that, if the initial good and malicious seeds could be selected based on peers' degrees, then HopRec and CredibleRank can achieve perfect performance.

  10. The Formation of "Hip-Hop Academicus"--How American Scholars Talk about the Academisation of Hip-Hop

    ERIC Educational Resources Information Center

    Soderman, Johan

    2013-01-01

    Social activism and education have been associated with hip-hop since it emerged in New York City 38 years ago. Therefore, it might not be surprising that universities have become interested in hip-hop. This article aims to highlight this "hip-hop academisation" and analyse the discursive mechanisms that manifest in these academisation…

  11. Featherless Dinosaurs and the Hip-Hop Simulacrum: Reconsidering Hip-Hop's Appropriateness for the Music Classroom

    ERIC Educational Resources Information Center

    Kruse, Adam J.

    2016-01-01

    This article offers considerations for music teachers interested in including hip-hop music in their classrooms but who might feel concerned with or overwhelmed by issues of appropriateness. Two concerns related to hip-hop music are examined: language and negative social themes. Commercial interests in hip-hop music have created a simulacrum (or…

  12. New implementation of the trajectory surface hopping method with use of the Zhu-Nakamura theory

    NASA Astrophysics Data System (ADS)

    Zhu, Chaoyuan; Nobusada, Katsuyuki; Nakamura, Hiroki

    2001-08-01

    A new implementation of the trajectory surface hopping (TSH) method is proposed to treat multidimensional nonadiabatic dynamics by incorporating the analytical Zhu-Nakamura semiclassical theory of nonadiabatic transition. The problem of classically forbidden hops in the TSH method can now be solved and dealt with just as easily as the classically allowed hops by introducing nonvertical hopping techniques. This is made possible, because the theory can treat both classically allowed and forbidden hops accurately in a unified way. The Zhu-Nakamura theory also enables us to predetermine important regions of potential energy surface before carrying out any dynamics calculations, and thus to save a lot of computational efforts. The charge transfer processes in the collinear H3+ system are studied numerically to test the new TSH method. Comparing the new and old versions of TSH with exact quantum calculations, the new method shows much better agreement with the exact calculations. It also works well when all trasitions are classically forbidden and the old method fails completely.

  13. Long-Term Oral Administration of Hop Flower Extracts Mitigates Alzheimer Phenotypes in Mice

    PubMed Central

    Sasaoka, Norio; Sakamoto, Megumi; Kanemori, Shoko; Kan, Michiru; Tsukano, Chihiro; Takemoto, Yoshiji; Kakizuka, Akira

    2014-01-01

    Coincident with the expanding population of aged people, the incidence of Alzheimer disease (AD) is rapidly increasing in most advanced countries. At present, no effective prophylactics are available. Among several pathological mechanisms proposed for AD, the “amyloid hypothesis” has been most widely accepted, in which accumulation or deposition of Aβ is considered to be the initial event. Thus, prevention of Aβ production would be an ideal strategy for the treatment or prevention of AD. Aβ is produced via the proteolytic cleavage of its precursor protein, APP (amyloid precursor protein), by two different enzymes, β and γ-secretases. Indeed, inhibitors against either or both enzymes have been developed and tested for clinical efficacy. Based on the “amyloid hypothesis”, we developed a luciferase-based screening method to monitor γ-secretase activity, screened more than 1,600 plant extracts, most of which have long been used in Chinese medicine, and observed that Hop extracts significantly inhibit Aβ production in cultured cells. A major component of the inhibitory activity was purified, and its chemical identity was determined by NMR to be Garcinielliptone HC. In vivo, oral administration of Hop extracts to AD model mice decreased Aβ depositions in the cerebral cortex of the parietal lobe, hippocampus, and artery walls (amyloid angiopathy) in the brains. In a Morris water maze test, AD model mice that had daily consumed Hop extracts in their drinking water showed significant mitigation of memory impairment at ages of 9 and 12 months. Moreover, in the open field test oral administration of Hop extracts also prevented an emotional disturbance that appeared in the AD mice at 18 months. Despite lifelong consumption of Hop extracts, no deleterious side effects were observed at any age. These results support the “amyloid hypothesis”, and indicate that Hop extract is a promising candidate for an effective prophylactic for AD. PMID:24489866

  14. Long-term oral administration of hop flower extracts mitigates Alzheimer phenotypes in mice.

    PubMed

    Sasaoka, Norio; Sakamoto, Megumi; Kanemori, Shoko; Kan, Michiru; Tsukano, Chihiro; Takemoto, Yoshiji; Kakizuka, Akira

    2014-01-01

    Coincident with the expanding population of aged people, the incidence of Alzheimer disease (AD) is rapidly increasing in most advanced countries. At present, no effective prophylactics are available. Among several pathological mechanisms proposed for AD, the "amyloid hypothesis" has been most widely accepted, in which accumulation or deposition of Aβ is considered to be the initial event. Thus, prevention of Aβ production would be an ideal strategy for the treatment or prevention of AD. Aβ is produced via the proteolytic cleavage of its precursor protein, APP (amyloid precursor protein), by two different enzymes, β and γ-secretases. Indeed, inhibitors against either or both enzymes have been developed and tested for clinical efficacy. Based on the "amyloid hypothesis", we developed a luciferase-based screening method to monitor γ-secretase activity, screened more than 1,600 plant extracts, most of which have long been used in Chinese medicine, and observed that Hop extracts significantly inhibit Aβ production in cultured cells. A major component of the inhibitory activity was purified, and its chemical identity was determined by NMR to be Garcinielliptone HC. In vivo, oral administration of Hop extracts to AD model mice decreased Aβ depositions in the cerebral cortex of the parietal lobe, hippocampus, and artery walls (amyloid angiopathy) in the brains. In a Morris water maze test, AD model mice that had daily consumed Hop extracts in their drinking water showed significant mitigation of memory impairment at ages of 9 and 12 months. Moreover, in the open field test oral administration of Hop extracts also prevented an emotional disturbance that appeared in the AD mice at 18 months. Despite lifelong consumption of Hop extracts, no deleterious side effects were observed at any age. These results support the "amyloid hypothesis", and indicate that Hop extract is a promising candidate for an effective prophylactic for AD. PMID:24489866

  15. Phase diagram of hopping conduction mechanisms in polymer nanofiber network

    SciTech Connect

    Li, Jeng-Ting; Lu, Yu-Cheng; Jiang, Shiau-Bin; Zhong, Yuan-Liang; Yeh, Jui-Ming

    2015-12-07

    Network formation by nanofiber crosslinking is usually in polymer materials as application in organic semiconductor devices. Electron hopping transport mechanisms depend on polymer morphology in network. Conducting polymers morphology in a random network structure is modeled by a quasi-one-dimensional system coupled of chains or fibers. We observe the varying hopping conduction mechanisms in the polyaniline nanofibers of the random network structure. The average diameter d of the nanofibers is varied from approximately 10 to 100 nm. The different dominant hopping mechanisms including Efros-Shklovskii variable-range hopping (VRH), Mott VRH, and nearest-neighbor hopping are dependent on temperature range and d in crossover changes. The result of this study is first presented in a phase diagram of hopping conduction mechanisms based on the theories of the random network model. The hopping conduction mechanism is unlike in normal semiconductor materials.

  16. Pre- and post-infection activity of fungicides in control of hop downy mildew

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optimum timing and use of fungicides for disease control are improved by an understanding of the characteristics of fungicide physical mode of action, although this information is lacking for hop downy mildew. Control of downy mildew on leaves was similar among fungicides tested when applied prevent...

  17. Genetic and epigenetic stability of cryopreserved and cold-stored hops (Humulus lupulus L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Standard cold storage and cryopreservation methods for hops (Humulus lupulus L.) are available but, to our knowledge, the genetic and epigenetic stability of the recovered plants were never tested. This study analyzed 51 accessions with two molecular techniques, Random Amplified DNA Polymorphism (R...

  18. Critical Hamiltonians with long range hopping

    NASA Astrophysics Data System (ADS)

    Levitov, L. S.

    1999-11-01

    Critical states are studied by a real space RG in the problem with strong diagonal disorder and long range power law hopping. The RG ow of the distribution of coupling parameters is characterized by a family of non-trivial fix points. We consider the RG flow of the distribution of participation ratios of eigenstates. Scaling of participation ratios is sensitive to the nature of the RG fix point. For some fix points, scaling of participation ratios is characterized by a distribution of exponents, rather than by a single exponent.The RG method can be generalized to treat certain fermionic Hamiltonians with disorder and long range hopping. We derive the RG for a model of interacting two-level systems. Besides couplings, in this problem the RG includes the density of states. The density of states is renormalized so that it develops a singularity near zero energy.

  19. Bipolaron Hopping Conduction in Boron Carbides

    SciTech Connect

    ASELAGE, TERRENCE L.; EMIN, D.; MCCREADY, STEVEN S.

    1999-09-20

    The electrical conductivities of boron carbides, B{sub 12+x}C{sub 3{minus}x} with 0.1 < x < 1.7, between 300 and 1200K suggest the hopping of a nearly temperature-independent density of small (bi)polarons. The activation energies of the nobilities are low, {approx} 0.16 eV, and are nearly independent of the composition. At lower temperatures, conductivities have non-Arrhenius temperature dependencies and strong sensitivity to carbon concentration. Percolative aspects of low-temperature hopping are evident in this sensitivity to composition. Boron carbides' Seebeck coefficients are anomalous in that (1) they are much larger than expected from boron carbides' large carrier densities and (2) they depend only weakly on the carrier density. Carrier-induced softening of local vibrations gives contributions to the Seebeck coefficient that mirror the magnitudes and temperature dependencies found in boron carbides.

  20. Eubacterium limosum activates isoxanthohumol from hops (Humulus lupulus L.) into the potent phytoestrogen 8-prenylnaringenin in vitro and in rat intestine.

    PubMed

    Possemiers, Sam; Rabot, Sylvie; Espín, Juan Carlos; Bruneau, Aurélia; Philippe, Catherine; González-Sarrías, Antonio; Heyerick, Arne; Tomás-Barberán, Francisco A; De Keukeleire, Denis; Verstraete, Willy

    2008-07-01

    Recently, it was shown that the exposure to the potent hop phytoestrogen 8-prenylnaringenin (8-PN) depends on intestinal bacterial activation of isoxanthohumol (IX), but this occurs in only one-third of tested individuals. As the butyrate-producing Eubacterium limosum can produce 8-PN from IX, a probiotic strategy was applied to investigate whether 8-PN production could be increased in low 8-PN producers, thus balancing phytoestrogen exposure. Using fecal samples from high (Hop +) and low (Hop -) 8-PN-producing individuals, a Hop + and Hop - dynamic intestinal model was developed. In parallel, Hop + and Hop - human microbiota-associated rats were developed, germ-free (GF) rats acting as negative controls. IX and then IX + E. limosum were administered in the intestinal model and to the rats, and changes in 8-PN production and exposure were assessed. After dosing IX, 80% was converted into 8-PN in the Hop + model and highest 8-PN production, plasma concentrations, and urinary and fecal excretion occurred in the Hop + rats. Administration of the bacterium triggered 8-PN production in the GF rats and increased 8-PN production in the Hop - model and Hop - rats. 8-PN excretion was similar in the feces (294.1 +/- 132.2 nmol/d) and urine (8.5 +/- 1.1 nmol/d ) of all rats (n = 18). In addition, butyrate production increased in all rats. In conclusion, intestinal microbiota determined 8-PN production and exposure after IX intake. Moreover, E. limosum administration increased 8-PN production in low producers, resulting in similar 8-PN production in all rats. PMID:18567753

  1. An Efficient Next Hop Selection Algorithm for Multi-Hop Body Area Networks

    PubMed Central

    Ayatollahitafti, Vahid; Ngadi, Md Asri; Mohamad Sharif, Johan bin; Abdullahi, Mohammed

    2016-01-01

    Body Area Networks (BANs) consist of various sensors which gather patient’s vital signs and deliver them to doctors. One of the most significant challenges faced, is the design of an energy-efficient next hop selection algorithm to satisfy Quality of Service (QoS) requirements for different healthcare applications. In this paper, a novel efficient next hop selection algorithm is proposed in multi-hop BANs. This algorithm uses the minimum hop count and a link cost function jointly in each node to choose the best next hop node. The link cost function includes the residual energy, free buffer size, and the link reliability of the neighboring nodes, which is used to balance the energy consumption and to satisfy QoS requirements in terms of end to end delay and reliability. Extensive simulation experiments were performed to evaluate the efficiency of the proposed algorithm using the NS-2 simulator. Simulation results show that our proposed algorithm provides significant improvement in terms of energy consumption, number of packets forwarded, end to end delay and packet delivery ratio compared to the existing routing protocol. PMID:26771586

  2. Communication: Global flux surface hopping in Liouville space.

    PubMed

    Wang, Linjun; Sifain, Andrew E; Prezhdo, Oleg V

    2015-11-21

    Recent years have witnessed substantial progress in the surface hopping (SH) formulation of non-adiabatic molecular dynamics. A generalization of the traditional fewest switches SH (FSSH), global flux SH (GFSH) utilizes the gross population flow between states to derive SH probabilities. The Liouville space formulation of FSSH puts state populations and coherences on equal footing, by shifting the hopping dynamics from Hilbert to Liouville space. Both ideas have shown superior results relative to the standard FSSH in Hilbert space, which has been the most popular approach over the past two and a half decades. By merging the two ideas, we develop GFSH in Liouville space. The new method is nearly as straightforward as the standard FSSH, and carries comparable computational expense. Tested with a representative super-exchange model, it gives the best performance among all existing techniques in the FSSH series. The obtained numerical results match almost perfectly the exact quantum mechanical solutions. Moreover, the results are nearly invariant under the choice of a basis state representation for SH, in contrast to the earlier techniques which exhibit notable basis set dependence. Unique to the developed approach, this property is particularly encouraging, because exact quantum dynamics is representation independent. GFSH in Liouville space significantly improves accuracy and applicability of SH for a broad range of chemical and physical processes. PMID:26590519

  3. Communication: Global flux surface hopping in Liouville space

    NASA Astrophysics Data System (ADS)

    Wang, Linjun; Sifain, Andrew E.; Prezhdo, Oleg V.

    2015-11-01

    Recent years have witnessed substantial progress in the surface hopping (SH) formulation of non-adiabatic molecular dynamics. A generalization of the traditional fewest switches SH (FSSH), global flux SH (GFSH) utilizes the gross population flow between states to derive SH probabilities. The Liouville space formulation of FSSH puts state populations and coherences on equal footing, by shifting the hopping dynamics from Hilbert to Liouville space. Both ideas have shown superior results relative to the standard FSSH in Hilbert space, which has been the most popular approach over the past two and a half decades. By merging the two ideas, we develop GFSH in Liouville space. The new method is nearly as straightforward as the standard FSSH, and carries comparable computational expense. Tested with a representative super-exchange model, it gives the best performance among all existing techniques in the FSSH series. The obtained numerical results match almost perfectly the exact quantum mechanical solutions. Moreover, the results are nearly invariant under the choice of a basis state representation for SH, in contrast to the earlier techniques which exhibit notable basis set dependence. Unique to the developed approach, this property is particularly encouraging, because exact quantum dynamics is representation independent. GFSH in Liouville space significantly improves accuracy and applicability of SH for a broad range of chemical and physical processes.

  4. Communication: Global flux surface hopping in Liouville space

    SciTech Connect

    Wang, Linjun E-mail: prezhdo@usc.edu; Prezhdo, Oleg V. E-mail: prezhdo@usc.edu; Sifain, Andrew E.

    2015-11-21

    Recent years have witnessed substantial progress in the surface hopping (SH) formulation of non-adiabatic molecular dynamics. A generalization of the traditional fewest switches SH (FSSH), global flux SH (GFSH) utilizes the gross population flow between states to derive SH probabilities. The Liouville space formulation of FSSH puts state populations and coherences on equal footing, by shifting the hopping dynamics from Hilbert to Liouville space. Both ideas have shown superior results relative to the standard FSSH in Hilbert space, which has been the most popular approach over the past two and a half decades. By merging the two ideas, we develop GFSH in Liouville space. The new method is nearly as straightforward as the standard FSSH, and carries comparable computational expense. Tested with a representative super-exchange model, it gives the best performance among all existing techniques in the FSSH series. The obtained numerical results match almost perfectly the exact quantum mechanical solutions. Moreover, the results are nearly invariant under the choice of a basis state representation for SH, in contrast to the earlier techniques which exhibit notable basis set dependence. Unique to the developed approach, this property is particularly encouraging, because exact quantum dynamics is representation independent. GFSH in Liouville space significantly improves accuracy and applicability of SH for a broad range of chemical and physical processes.

  5. The molecular structure of hop latent viroid (HLV), a new viroid occurring worldwide in hops.

    PubMed Central

    Puchta, H; Ramm, K; Sänger, H L

    1988-01-01

    A new viroid which does not seem to produce any symptoms of disease, and is therefore tentatively named hop latent viroid (HLV) was found to occur worldwide in hops. HLV proved to be infectious when mechanically inoculated onto viroid- and virus-free hops. The viroid nature of HLV was also substantiated by sequence analysis which revealed that HLV is a circular RNA consisting of 256 nucleotides, that can be arranged into the viroid-specific, rod-like secondary structure. HLV also contains the central conserved region typical for most of the presently known viroids. However HLV does not contain the viroid-specific oligo(A) stretch in the upper left part of its rod-like molecule. Because of this feature and a sequence similarity with the prototypes of the other viroid groups below 55%, HLV can be regarded as the first member of a new viroid group. Images PMID:2454454

  6. A singularity free surface hopping expansion for the multistate wave function.

    PubMed

    Herman, Michael F

    2009-12-01

    A version of a surface hopping wave function for nonadiabatic multistate problems, which is free of turning point singularities, is derived and tested. The primitive semiclassical form of the particular surface hopping method considered has been shown to be highly accurate, even for classically forbidden processes. However, this semiclassical wave function displays the usual singular behavior at turning points and caustics in the classical motion. Numerical data has shown that this somewhat reduces its accuracy when the energy is near the crossing energy of the diabatic electronic surfaces. The singularity free version of this surface hopping wave function is derived by partitioning the x-axis into a large number of small steps for one dimensional problems. The adiabatic electronic energy surfaces are approximated to be linear functions within each step. The matching conditions required by the continuity of the wave function and its derivative at each step boundary provide the needed conditions to obtain the amplitudes for changes in electronic state and/or reflection of the trajectory for the motion of the nuclei. This leads to a form of the surface hopping wave function that is free of turning point singularities. The method is tested for a one dimensional model problem, and it is found to be highly accurate at all energies considered, even when the energy is near the crossing energy. PMID:19968338

  7. Rethinking Pedagogy in Urban Spaces: Implementing Hip-Hop Pedagogy in the Urban Science Classroom

    ERIC Educational Resources Information Center

    Adjapong, Edmund S.; Emdin, Christopher

    2015-01-01

    A significant amount of research regarding Hip-Hop Based Education (HHBE) fails to provide insight on how to incorporate elements of Hip-Hop into daily teaching practices; rather Hip-Hop based educators focus mainly on incorporating Hip-Hop culture into curricula. This study explores the benefits of using two specific Hip-Hop pedagogical practices…

  8. A Pseudomonas syringae pv. tomato DC3000 mutant lacking the type III effector HopQ1-1 is able to cause disease in the model plant Nicotiana benthamiana.

    PubMed

    Wei, Chia-Fong; Kvitko, Brian H; Shimizu, Rena; Crabill, Emerson; Alfano, James R; Lin, Nai-Chun; Martin, Gregory B; Huang, Hsiou-Chen; Collmer, Alan

    2007-07-01

    The model pathogen Pseudomonas syringae pv. tomato DC3000 causes bacterial speck in tomato and Arabidopsis, but Nicotiana benthamiana, an important model plant, is considered to be a non-host. Strain DC3000 injects approximately 28 effector proteins into plant cells via the type III secretion system (T3SS). These proteins were individually delivered into N. benthamiana leaf cells via T3SS-proficient Pseudomonas fluorescens, and eight, including HopQ1-1, showed some capacity to cause cell death in this test. Four gene clusters encoding 13 effectors were deleted from DC3000: cluster II (hopH1, hopC1), IV (hopD1, hopQ1-1, hopR1), IX (hopAA1-2, hopV1, hopAO1, hopG1), and native plasmid pDC3000A (hopAM1-2, hopX1, hopO1-1, hopT1-1). DC3000 mutants deleted for cluster IV or just hopQ1-1 acquired the ability to grow to high levels and produce bacterial speck lesions in N. benthamiana. HopQ1-1 showed other hallmarks of an avirulence determinant in N. benthamiana: expression in the tobacco wildfire pathogen P. syringae pv. tabaci 11528 rendered this strain avirulent in N. benthamiana, and elicitation of the hypersensitive response in N. benthamiana by HopQ1-1 was dependent on SGT1. DC3000 polymutants involving other effector gene clusters in a hopQ1-1-deficient background revealed that clusters II and IX contributed to the severity of lesion symptoms in N. benthamiana, as well as in Arabidopsis and tomato. The results support the hypothesis that the host ranges of P. syringae pathovars are limited by the complex interactions of effector repertoires with plant anti-effector surveillance systems, and they demonstrate that N. benthamiana can be a useful model host for DC3000. PMID:17559511

  9. Hip-Hop Is the Healer: Sense of Belonging and Diversity among Hip-Hop Collegians

    ERIC Educational Resources Information Center

    Sulé, V. Thandi

    2016-01-01

    Sense of belonging is recognized as a factor contributing to persistence to graduation. Furthermore, interactional diversity is associated with learning and civic outcomes--touted higher education goals. Hip-hop culture, one of the most influential cultural creations of the mid-20th century, has succeeded in attracting devotees from diverse…

  10. Pharmacokinetics of Prenylated Hop Phenols in Women Following Oral Administration of a Standardized Extract of Hops

    PubMed Central

    van Breemen, Richard B.; Yuan, Yang; Banuvar, Suzanne; Shulman, Lee P.; Qiu, Xi; Alvarenga, René F. Ramos; Chen, Shao-Nong; Dietz, Birgit M.; Bolton, Judy L.; Pauli, Guido F.; Krause, Elizabeth; Viana, Marlos; Nikolic, Dejan

    2014-01-01

    SCOPE Women seeking alternatives to hormone replacement therapy for menopausal symptoms often try botanical dietary supplements containing extracts of hops (Humulus lupulus L.). Hops contain 8-prenylnaringenin (8-PN), a potent phytoestrogen, the related flavanones 6-prenylnaringenin (6-PN) and isoxanthohumol (IX), and the prenylated chalcone xanthohumol (XN). METHODS AND RESULTS After chemically and biologically standardizing an extract of spent hops to these marker compounds, an escalating dose study was carried out in menopausal women to evaluate safety and pharmacokinetics. 8-PN, 6-PN, IX, and XN, sex hormones, and prothrombin time (PT/INR) were determined in blood samples and/or 24-h urine samples. There was no effect on sex hormones or blood clotting. The maximum serum concentrations of the prenylated phenols were dose-dependent and were reached from 2 to 7 h, indicating slow absorption. The marker compounds formed glucuronides that were found in serum and urine. Secondary peaks at 5 h in the serum concentration-time curves indicated enterohepatic recirculation. The serum concentration-time curves indicated demethylation of IX to form 8-PN and cyclization of XN to IX. Slow absorption and enterohepatic recirculation contributed to half-lives exceeding 20 h. CONCLUSION This human study indicated long half-lives of the estrogenic and proestrogenic prenylated phenols in hops but no acute toxicity. PMID:25045111

  11. Analysis of the Trajectory Surface Hopping Method from the Markov State Model Perspective

    NASA Astrophysics Data System (ADS)

    Akimov, Alexey V.; Trivedi, Dhara; Wang, Linjun; Prezhdo, Oleg V.

    2015-09-01

    We analyze the applicability of the seminal fewest switches surface hopping (FSSH) method of Tully to modeling quantum transitions between electronic states that are not coupled directly, in the processes such as Auger recombination. We address the known deficiency of the method to describe such transitions by introducing an alternative definition for the surface hopping probabilities, as derived from the Markov state model perspective. We show that the resulting transition probabilities simplify to the quantum state populations derived from the time-dependent Schrödinger equation, reducing to the rapidly switching surface hopping approach of Tully and Preston. The resulting surface hopping scheme is simple and appeals to the fundamentals of quantum mechanics. The computational approach is similar to the FSSH method of Tully, yet it leads to a notably different performance. We demonstrate that the method is particularly accurate when applied to superexchange modeling. We further show improved accuracy of the method, when applied to one of the standard test problems. Finally, we adapt the derived scheme to atomistic simulation, combine it with the time-domain density functional theory, and show that it provides the Auger energy transfer timescales which are in good agreement with experiment, significantly improving upon other considered techniques.

  12. Collision-based mechanics of bipedal hopping.

    PubMed

    Gutmann, Anne K; Lee, David V; McGowan, Craig P

    2013-08-23

    The muscle work required to sustain steady-speed locomotion depends largely upon the mechanical energy needed to redirect the centre of mass and the degree to which this energy can be stored and returned elastically. Previous studies have found that large bipedal hoppers can elastically store and return a large fraction of the energy required to hop, whereas small bipedal hoppers can only elastically store and return a relatively small fraction. Here, we consider the extent to which large and small bipedal hoppers (tammar wallabies, approx. 7 kg, and desert kangaroo rats, approx. 0.1 kg) reduce the mechanical energy needed to redirect the centre of mass by reducing collisions. We hypothesize that kangaroo rats will reduce collisions to a greater extent than wallabies since kangaroo rats cannot elastically store and return as high a fraction of the mechanical energy of hopping as wallabies. We find that kangaroo rats use a significantly smaller collision angle than wallabies by employing ground reaction force vectors that are more vertical and center of mass velocity vectors that are more horizontal and thereby reduce their mechanical cost of transport. A collision-based approach paired with tendon morphometry may reveal this effect more generally among bipedal runners and quadrupedal trotters. PMID:23843217

  13. Chicano Hip-Hop as Interethnic Contact Zone

    ERIC Educational Resources Information Center

    McFarland, Pancho

    2008-01-01

    The critical study of rap music and hip-hop culture has the potential to expand Americans understanding of race and culture in the United States. Hip-hop culture as a multiracial, multiethnic phenomenon reveals the ways in which race relations over the past thirty years have become increasingly complex. The theories and concepts that they use to…

  14. Hip-Hop, the "Obama Effect," and Urban Science Education

    ERIC Educational Resources Information Center

    Emdin, Christopher; Lee, Okhee

    2012-01-01

    Background/Context: With the ever increasing diversity of schools, and the persistent need to develop teaching strategies for the students who attend today's urban schools, hip-hop culture has been proposed to be a means through which urban youth can find success in school. As a result, studies of the role of hip-hop in urban education have grown…

  15. Hip Hop as Empowerment: Voices in El Alto, Bolivia

    ERIC Educational Resources Information Center

    Tarifa, Ariana

    2012-01-01

    In response to neoliberal policies that have been in place since 1985, Bolivian young people have increasingly used hip hop music as a means of protest and to reclaim social and political participation. Hip hop in Latin America tells the story of the struggles that marginalized people have suffered, and speaks to the effects of international…

  16. Towards a Pedagogy of Hip Hop in Urban Teacher Education

    ERIC Educational Resources Information Center

    Bridges, Thurman

    2011-01-01

    This article draws from a qualitative study often Black male K-12 teachers from the Hip Hop Generation who are closely connected to Hip Hop culture and have been effective in addressing the academic and social needs of Black boys. Through an analysis of their social, educational and cultural experiences, this article highlights three organizing…

  17. Hip Hop Is Now: An Evolving Youth Culture

    ERIC Educational Resources Information Center

    Taylor, Carl; Taylor, Virgil

    2007-01-01

    Emerging from Rap music, Hip Hop has become a lifestyle to many modern youth around the world. Embodying both creativity and controversy, Hip Hop mirrors the values, violence, and hypocrisy of modern culture. The authors dispel some of the simplistic views that surround this evolving youth movement embraced by millions of young people who are…

  18. Framing and Reviewing Hip-Hop Educational Research

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2009-01-01

    Hip-hop has become relevant to the field of education because of its implications for understanding language, learning, identity, curriculum, and other areas. This integrative review provides historical context and cohesion for the burgeoning and discursive body of hip-hop scholarship by framing it according to three heuristic categories and…

  19. Christian Hip Hop as Pedagogy: A South African Case Study

    ERIC Educational Resources Information Center

    Abraham, Ibrahim

    2015-01-01

    Drawing on interviews with creators of Christian hip hop music in South Africa, this article demonstrates that this genre of popular music and youth culture is utilised as a form of pedagogy to transmit religious beliefs and values to contemporary youth. The pedagogical aspects of hip hop have been recognised in research on the topic, but the…

  20. Toward Hip-Hop Pedagogies for Music Education

    ERIC Educational Resources Information Center

    Kruse, Adam J.

    2016-01-01

    Music education scholarship in the areas of popular, vernacular, and participatory musicianship has grown in the past decades; however, music education research concerned specifically with hip-hop has been relatively scarce. Because hip-hop music can differ tremendously from the traditional western genres with which many music educators are most…

  1. Hop powdery mildew control through alteration of spring pruning practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 1997, Podosphaera macularis, the causal agent of hop powdery mildew, has become a recurrent threat to hops in the Pacific Northwest because of the potential to reduce cone yield and quality. Disease management practices often involve preventative fungicide applications, but alternative approac...

  2. Framing Hip Hop: New Methodologies for New Times

    ERIC Educational Resources Information Center

    Dimitriadis, Greg

    2015-01-01

    This article revisits the central impulse behind early advocacy for ethnographic approaches to hip hop--that critics should try as much as possible to limit their own certainties around what hip hop can and might mean. While ethnographic approaches can engender the kinds of personal dislocations that allow for this negotiation, they do not…

  3. Optimum Detection Of Slow-Frequency-Hopping Signals

    NASA Technical Reports Server (NTRS)

    Levitt, Barry K.; Cheng, Unjeng

    1994-01-01

    Two papers present theoretical analyses of various schemes for coherent and noncoherent detection of M-ary-frequency-shift-keyed (MFSK) signals with slow frequency hopping. Special attention focused on continuous-phase-modulation (CPM) subset of SFH/MFSK signals, for which frequency modulation such carrier phase remains continuous (albeit unknown) during each hop.

  4. Hip Hop Culture's OGs: A Narrative Inquiry into the Intersection of Hip Hop Culture, Black Males and Their Schooling Experiences

    ERIC Educational Resources Information Center

    Buchanan, Ian P.

    2013-01-01

    Using a critical race lens, this narrative study employs a focus group design to explore the intersections between black males, hip hop culture and schooling experiences. To provide a sociocultural grounding, this study first reviews the research literature around hip hop culture.s sociocultural development and its impact as a culture force that…

  5. Hip-Hop Is My Passport! Using Hip-Hop and Digital Literacies to Understand Global Citizenship Education

    ERIC Educational Resources Information Center

    Horton, Akesha Monique

    2013-01-01

    Hip-hop has exploded around the world among youth. It is not simply an American source of entertainment; it is a global cultural movement that provides a voice for youth worldwide who have not been able to express their "cultural world" through mainstream media. The emerging field of critical hip-hop pedagogy has produced little…

  6. Real-Time On-Board Airborne Demonstration of High-Speed On-Board Data Processing for Science Instruments (HOPS)

    NASA Technical Reports Server (NTRS)

    Beyon, Jeffrey Y.; Ng, Tak-Kwong; Davis, Mitchell J.; Adams, James K.; Bowen, Stephen C.; Fay, James J.; Hutchinson, Mark A.

    2015-01-01

    The project called High-Speed On-Board Data Processing for Science Instruments (HOPS) has been funded by NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) program since April, 2012. The HOPS team recently completed two flight campaigns during the summer of 2014 on two different aircrafts with two different science instruments. The first flight campaign was in July, 2014 based at NASA Langley Research Center (LaRC) in Hampton, VA on the NASA's HU-25 aircraft. The science instrument that flew with HOPS was Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) CarbonHawk Experiment Simulator (ACES) funded by NASA's Instrument Incubator Program (IIP). The second campaign was in August, 2014 based at NASA Armstrong Flight Research Center (AFRC) in Palmdale, CA on the NASA's DC-8 aircraft. HOPS flew with the Multifunctional Fiber Laser Lidar (MFLL) instrument developed by Excelis Inc. The goal of the campaigns was to perform an end-to-end demonstration of the capabilities of the HOPS prototype system (HOPS COTS) while running the most computationally intensive part of the ASCENDS algorithm real-time on-board. The comparison of the two flight campaigns and the results of the functionality tests of the HOPS COTS are presented in this paper.

  7. Real-time on-board airborne demonstration of high-speed on-board data processing for science instruments (HOPS)

    NASA Astrophysics Data System (ADS)

    Beyon, Jeffrey Y.; Ng, Tak-Kwong; Davis, Mitchell J.; Adams, James K.; Bowen, Stephen C.; Fay, James J.; Hutchinson, Mark A.

    2015-05-01

    The project called High-Speed On-Board Data Processing for Science Instruments (HOPS) has been funded by NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) program since April, 2012. The HOPS team recently completed two flight campaigns during the summer of 2014 on two different aircrafts with two different science instruments. The first flight campaign was in July, 2014 based at NASA Langley Research Center (LaRC) in Hampton, VA on the NASA's HU-25 aircraft. The science instrument that flew with HOPS was Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) CarbonHawk Experiment Simulator (ACES) funded by NASA's Instrument Incubator Program (IIP). The second campaign was in August, 2014 based at NASA Armstrong Flight Research Center (AFRC) in Palmdale, CA on the NASA's DC-8 aircraft. HOPS flew with the Multifunctional Fiber Laser Lidar (MFLL) instrument developed by Excelis Inc. The goal of the campaigns was to perform an end-to-end demonstration of the capabilities of the HOPS prototype system (HOPS COTS) while running the most computationally intensive part of the ASCENDS algorithm real-time on-board. The comparison of the two flight campaigns and the results of the functionality tests of the HOPS COTS are presented in this paper.

  8. Communication devices for network-hopping communications and methods of network-hopping communications

    DOEpatents

    Buttles, John W.

    2011-12-20

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The processing circuitry is configured to execute computer programming code. Storage media is coupled to the processing circuitry and includes computer programming code configured to cause the processing circuitry to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  9. Communication devices for network-hopping communications and methods of network-hopping communications

    DOEpatents

    Buttles, John W

    2013-04-23

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The system controller is configured to execute computer programming code. Storage media is coupled to the system controller and includes computer programming code configured to cause the system controller to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  10. Anomalous hopping exponents of ultrathin metal films

    NASA Astrophysics Data System (ADS)

    Phillips, J. C.

    2001-07-01

    Under the above title Markovic et al. [Phys. Rev. B 62, 2195 (2000)] summarized their and others' low-temperature data that show that a consistent underlying conduction mechanism is needed to explain thermally activated resistivities, with an exponent x=0.75(5), on films of Ag, Bi, Pb, and Pd, with thicknesses of 5-15 Å. While this x cannot be explained by any kind of conventional continuum hopping model, with or without Coulomb interactions, here it is shown that the exponent x=34 is the direct result of a filamentary vibron quantum percolation model appropriate to a granular network film. The concepts used in this model were recently used to derive finite-size scaling exponents and/or phase diagrams in many other contexts, including network glasses, the impurity band metal-insulator transition, high-temperature superconductors, and evolutionary biology.

  11. Isoxanthohumol--Biologically active hop flavonoid.

    PubMed

    Żołnierczyk, Anna Katarzyna; Mączka, Wanda Krystyna; Grabarczyk, Małgorzata; Wińska, Katarzyna; Woźniak, Edyta; Anioł, Mirosław

    2015-06-01

    Isoxanthohumol (IXN), apart from xanthohumol (XN) and 8-prenylnaringenin (8PN), is one of the most important prenylflavonoids found in hops. Another natural source of this compound is a shrub Sophora flavescens, used in traditional Chinese medicine. Main dietary source of IXN is beer, and the compound is produced from XN during wort boiling. In the human body, the compound is O-demethylated to 8PN, the strongest known phytoestrogen. This process takes place in the liver and in the intestine, where it is mediated by local microflora. It has been reported in some studies that even though beer contains small amounts of hops and its preparations, these compounds may affect the functioning of the human body. IXN exhibits an antiproliferative activity against human cell lines typical for breast cancer (MCF-7), ovarian cancer (A-2780), prostate cancer (DU145 and PC-3), and colon cancer (HT-29 and SW620) cells. It strongly inhibits the activation of the following carcinogens: 2-amino-3-methylimidazol-[4,5-f]quinoline and aflatoxin B1 (AFB1) via human cytochrome P450 (CYP1A2). It also inhibits the production of prostate specific antigen (PSA). IXN significantly reduces the expression of transforming growth factor-β (TGF-β) in the case of invasive breast cancer MDA-MB-231. It interferes with JAK/STAT signaling pathway and inhibits the expression of pro1inflammatory genes in the monoblastic leukemia cell line (MonoMac6). It activates apoptosis in human umbilical vein endothelial cells (HUVEC) and human aortic smooth muscle cells (HASMCs). In addition, IXN shows an antiviral activity towards herpes viruses (HSV1 and HSV2) and bovine viral diarrhea virus (BVDV). PMID:25771121

  12. Power-Hop: A Pervasive Observation for Real Complex Networks

    PubMed Central

    Papalexakis, Evangelos; Hooi, Bryan; Pelechrinis, Konstantinos; Faloutsos, Christos

    2016-01-01

    Complex networks have been shown to exhibit universal properties, with one of the most consistent patterns being the scale-free degree distribution, but are there regularities obeyed by the r-hop neighborhood in real networks? We answer this question by identifying another power-law pattern that describes the relationship between the fractions of node pairs C(r) within r hops and the hop count r. This scale-free distribution is pervasive and describes a large variety of networks, ranging from social and urban to technological and biological networks. In particular, inspired by the definition of the fractal correlation dimension D2 on a point-set, we consider the hop-count r to be the underlying distance metric between two vertices of the network, and we examine the scaling of C(r) with r. We find that this relationship follows a power-law in real networks within the range 2 ≤ r ≤ d, where d is the effective diameter of the network, that is, the 90-th percentile distance. We term this relationship as power-hop and the corresponding power-law exponent as power-hop exponent h. We provide theoretical justification for this pattern under successful existing network models, while we analyze a large set of real and synthetic network datasets and we show the pervasiveness of the power-hop. PMID:26974560

  13. Particle hopping vs. fluid-dynamical models for traffic flow

    SciTech Connect

    Nagel, K.

    1995-12-31

    Although particle hopping models have been introduced into traffic science in the 19509, their systematic use has only started recently. Two reasons for this are, that they are advantageous on modem computers, and that recent theoretical developments allow analytical understanding of their properties and therefore more confidence for their use. In principle, particle hopping models fit between microscopic models for driving and fluiddynamical models for traffic flow. In this sense, they also help closing the conceptual gap between these two. This paper shows connections between particle hopping models and traffic flow theory. It shows that the hydrodynamical limits of certain particle hopping models correspond to the Lighthill-Whitham theory for traffic flow, and that only slightly more complex particle hopping models produce already the correct traffic jam dynamics, consistent with recent fluid-dynamical models for traffic flow. By doing so, this paper establishes that, on the macroscopic level, particle hopping models are at least as good as fluid-dynamical models. Yet, particle hopping models have at least two advantages over fluid-dynamical models: they straightforwardly allow microscopic simulations, and they include stochasticity.

  14. Scaffold hopping in drug discovery using inductive logic programming.

    PubMed

    Tsunoyama, Kazuhisa; Amini, Ata; Sternberg, Michael J E; Muggleton, Stephen H

    2008-05-01

    In chemoinformatics, searching for compounds which are structurally diverse and share a biological activity is called scaffold hopping. Scaffold hopping is important since it can be used to obtain alternative structures when the compound under development has unexpected side-effects. Pharmaceutical companies use scaffold hopping when they wish to circumvent prior patents for targets of interest. We propose a new method for scaffold hopping using inductive logic programming (ILP). ILP uses the observed spatial relationships between pharmacophore types in pretested active and inactive compounds and learns human-readable rules describing the diverse structures of active compounds. The ILP-based scaffold hopping method is compared to two previous algorithms (chemically advanced template search, CATS, and CATS3D) on 10 data sets with diverse scaffolds. The comparison shows that the ILP-based method is significantly better than random selection while the other two algorithms are not. In addition, the ILP-based method retrieves new active scaffolds which were not found by CATS and CATS3D. The results show that the ILP-based method is at least as good as the other methods in this study. ILP produces human-readable rules, which makes it possible to identify the three-dimensional features that lead to scaffold hopping. A minor variant of a rule learnt by ILP for scaffold hopping was subsequently found to cover an inhibitor identified by an independent study. This provides a successful result in a blind trial of the effectiveness of ILP to generate rules for scaffold hopping. We conclude that ILP provides a valuable new approach for scaffold hopping. PMID:18457387

  15. Biotransformation of hop aroma terpenoids by ale and lager yeasts.

    PubMed

    King, Andrew J; Dickinson, J Richard

    2003-03-01

    Terpenoids are important natural flavour compounds, which are introduced to beer via hopping. It has been shown recently that yeasts are able to biotransform some monoterpene alcohols. As a first step towards examining whether yeasts are capable of altering hop terpenoids during the brewing of beer, we investigated whether they were transformed when an ale and lager yeast were cultured in the presence of a commercially available syrup. Both yeasts transformed the monoterpene alcohols geraniol and linalool. The lager yeast also produced acetate esters of geraniol and citronellol. The major terpenoids of hop oil, however, were not biotransformed. Oxygenated terpenoids persisted much longer than the alkenes. PMID:12702246

  16. Let Me Blow Your Mind: Hip Hop Feminist Futures in Theory and Praxis

    ERIC Educational Resources Information Center

    Lindsey, Treva B.

    2015-01-01

    This essay brings together key theoretical interventions in hip-hop feminism to explore the continued, but undervalued, significance of hip-hop feminism in urban education. More specifically, the essay challenges narrow conceptualizations of the "hip hop subject" as Black and male by using hip-hop feminist theory to incorporate the lived…

  17. 60. View of lined canal and hop barn, looking southwest. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    60. View of lined canal and hop barn, looking southwest. Photo by Robin Lee Tedder, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  18. 59. View of lined canal east of bellmouth near hop ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    59. View of lined canal east of bellmouth near hop barn, looking southwest. Photo by Robin Lee Tedder, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  19. Fate of xanthohumol and related prenylflavonoids from hops to beer.

    PubMed

    Stevens, J F; Taylor, A W; Clawson, J E; Deinzer, M L

    1999-06-01

    The fate of three prenylated flavonoids of the chalcone type, xanthohumol, desmethylxanthohumol, and 3'-geranylchalconaringenin, was monitored with LC/MS-MS from hops (Humulus lupulus L.) to beer in two brewing trials. The three prenylchalcones were largely converted into their isomeric flavanones, isoxanthohumol, prenylnaringenins, and geranylnaringenins, respectively, in the boiling wort. Losses of prenylflavonoids were due to incomplete extraction from the hops into the wort (13-25%), adsorption to insoluble malt proteins (18-26%), and adsorption to yeast cells (11-32%) during fermentation. The overall yield of xanthohumol, after lagering of the beer and largely in the form of isoxanthohumol, amounted to 22-30% of the hops' xanthohumol. About 10% of the hops' desmethylxanthohumol, completely converted into prenylnaringenins, remained in the beers. 3'-Geranylchalconaringenin behaved similarly to desmethylxanthohumol. Solubility experiments indicated that (1) malt carbohydrates form soluble complexes with xanthohumol and isoxanthohumol and (2) solubility does not dictate the isoxanthohumol levels of finished beers. PMID:10794646

  20. Understanding the Surface Hopping View of Electronic Transitions and Decoherence

    NASA Astrophysics Data System (ADS)

    Subotnik, Joseph E.; Jain, Amber; Landry, Brian; Petit, Andrew; Ouyang, Wenjun; Bellonzi, Nicole

    2016-05-01

    We present a current, up-to-date review of the surface hopping methodology for solving nonadiabatic problems, 25 years after Tully published the fewest switches surface hopping algorithm. After reviewing the original motivation for and failures of the algorithm, we give a detailed examination of modern advances, focusing on both theoretical and practical issues. We highlight how one can partially derive surface hopping from the Schrödinger equation in the adiabatic basis, how one can change basis within the surface hopping algorithm, and how one should understand and apply the notions of decoherence and wavepacket bifurcation. The question of time reversibility and detailed balance is also examined at length. Recent applications to photoexcited conjugated polymers are discussed briefly.

  1. Correlated barrier hopping of CuO nanoparticles

    NASA Astrophysics Data System (ADS)

    Koshy, Jiji; Soosen, Samuel. M.; Chandran, Anoop; George, K. C.

    2015-12-01

    The ac conduction mechanism in copper oxide nanoparticles with 8 nm size, synthesized by a precipitation method was studied by analyzing ac conductivity in the frequency range of 50 Hz-1 MHz and in the temperature range of 373-573 K. X-ray diffraction and transmission electron microscopy (TEM) were employed for the structural and morphological characterization of CuO nanoparticles. The experimental and theoretical investigations suggested that the ac conduction mechanism in CuO nanoparticles can be successfully explained by a correlated barrier hopping model, which provided reasonable values for the maximum barrier height and characteristic relaxation time. It was also found that bipolaron hopping become prominent up to a particular temperature and beyond that single polaron hopping predominates. Physical parameters such as hopping distance and density of defect states were also calculated. Photoluminescence studies confirm the presence of a surface defect in CuO nanoparticles.

  2. Adaptive time steps in trajectory surface hopping simulations.

    PubMed

    Spörkel, Lasse; Thiel, Walter

    2016-05-21

    Trajectory surface hopping (TSH) simulations are often performed in combination with active-space multi-reference configuration interaction (MRCI) treatments. Technical problems may arise in such simulations if active and inactive orbitals strongly mix and switch in some particular regions. We propose to use adaptive time steps when such regions are encountered in TSH simulations. For this purpose, we present a computational protocol that is easy to implement and increases the computational effort only in the critical regions. We test this procedure through TSH simulations of a GFP chromophore model (OHBI) and a light-driven rotary molecular motor (F-NAIBP) on semiempirical MRCI potential energy surfaces, by comparing the results from simulations with adaptive time steps to analogous ones with constant time steps. For both test molecules, the number of successful trajectories without technical failures rises significantly, from 53% to 95% for OHBI and from 25% to 96% for F-NAIBP. The computed excited-state lifetime remains essentially the same for OHBI and increases somewhat for F-NAIBP, and there is almost no change in the computed quantum efficiency for internal rotation in F-NAIBP. We recommend the general use of adaptive time steps in TSH simulations with active-space CI methods because this will help to avoid technical problems, increase the overall efficiency and robustness of the simulations, and allow for a more complete sampling. PMID:27208937

  3. Adaptive time steps in trajectory surface hopping simulations

    NASA Astrophysics Data System (ADS)

    Spörkel, Lasse; Thiel, Walter

    2016-05-01

    Trajectory surface hopping (TSH) simulations are often performed in combination with active-space multi-reference configuration interaction (MRCI) treatments. Technical problems may arise in such simulations if active and inactive orbitals strongly mix and switch in some particular regions. We propose to use adaptive time steps when such regions are encountered in TSH simulations. For this purpose, we present a computational protocol that is easy to implement and increases the computational effort only in the critical regions. We test this procedure through TSH simulations of a GFP chromophore model (OHBI) and a light-driven rotary molecular motor (F-NAIBP) on semiempirical MRCI potential energy surfaces, by comparing the results from simulations with adaptive time steps to analogous ones with constant time steps. For both test molecules, the number of successful trajectories without technical failures rises significantly, from 53% to 95% for OHBI and from 25% to 96% for F-NAIBP. The computed excited-state lifetime remains essentially the same for OHBI and increases somewhat for F-NAIBP, and there is almost no change in the computed quantum efficiency for internal rotation in F-NAIBP. We recommend the general use of adaptive time steps in TSH simulations with active-space CI methods because this will help to avoid technical problems, increase the overall efficiency and robustness of the simulations, and allow for a more complete sampling.

  4. Spin-memory effect and negative magnetoresistance in hopping conductivity

    NASA Astrophysics Data System (ADS)

    Agam, Oded; Aleiner, Igor L.; Spivak, Boris

    2014-03-01

    We propose a mechanism for negative isotropic magnetoresistance in the hopping regime. It results from a memory effect encrypted into spin correlations that are not taken into account by the conventional theory of hopping conductivity. The spin correlations are generated by the nonequilibrium electric currents and lead to the decrease of the conductivity. The application of the magnetic field destroys the correlations thus enhancing the conductance. This effect can occur even at magnetic fields as small as a few gauss.

  5. Proton hopping: a proposed mechanism for myelinated axon nerve impulses.

    PubMed

    Kier, Lemont B; Tombes, Robert M

    2013-04-01

    Myelinated axon nerve impulses travel 100 times more rapidly than impulses in non-myelinated axons. Increased speed is currently believed to be due to 'hopping' or 'saltatory propagation' along the axon, but the mechanism by which impulses flow has never been adequately explained. We have used modeling approaches to simulate a role for proton hopping in the space between the plasma membrane and myelin sheath as the mechanism of nerve action-potential flow. PMID:23576345

  6. Gold Binding by Native and Chemically Modified Hops Biomasses

    DOE PAGESBeta

    López, M. Laura; Gardea-Torresdey, J. L.; Peralta-Videa, J. R.; de la Rosa, G.; Armendáriz, V.; Herrera, I.; Troiani, H.; Henning, J.

    2005-01-01

    Heavy metals from mining, smelting operations and other industrial processing facilities pollute wastewaters worldwide. Extraction of metals from industrial effluents has been widely studied due to the economic advantages and the relative ease of technical implementation. Consequently, the search for new and improved methodologies for the recovery of gold has increased. In this particular research, the use of cone hops biomass ( Humulus lupulus ) was investigated as a new option for gold recovery. The results showed that the gold binding to native hops biomass was pH dependent from pH 2 to pH 6, with a maximum percentage bindingmore » at pH 3. Time dependency studies demonstrated that Au(III) binding to native and modified cone hops biomasses was found to be time independent at pH 2 while at pH 5, it was time dependent. Capacity experiments demonstrated that at pH 2, esterified hops biomass bound 33.4 mg Au/g of biomass, while native and hydrolyzed hops biomasses bound 28.2 and 12.0 mg Au/g of biomass, respectively. However, at pH 5 the binding capacities were 38.9, 37.8 and 11.4 mg of Au per gram of native, esterified and hydrolyzed hops biomasses, respectively.« less

  7. Coding for slow frequency hopped differential phase shift keying

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Gulliver, T. A.; Mason, Lloyd J.; Blake, Ian F.

    The performance of Reed-Solomon (RS) error-correcting codes with slow frequency hopped (SFH) differential phase shift keying (DPSK) signaling is analyzed and evaluated under worst-case partial-band noise (PBN) and worst-case multitone (MT) jamming. The results of a study of the bit error rate (BER) performance of this coded system are presented. A representative set of the performance curves is shown. SFH is used because the differential signaling required only the phase of the previous received signal as a reference. Using DPSK eliminates the need to establish a phase reference for the hop, as with coherent signaling. From the results it is clear that the number of codeword symbols per hop must be small in order for the RS code to provide protection against jamming. Otherwise, no improvement over uncoded DPSK is gained. Lowering the symbols per hop can be achieved either by reducing the number of bits per hop, or interleaving the RS codewords to a depth determined by the hop length and RS code parameters.

  8. Accurate water maser positions from HOPS

    NASA Astrophysics Data System (ADS)

    Walsh, Andrew J.; Purcell, Cormac R.; Longmore, Steven N.; Breen, Shari L.; Green, James A.; Harvey-Smith, Lisa; Jordan, Christopher H.; Macpherson, Christopher

    2014-08-01

    We report on high spatial resolution water maser observations, using the Australia Telescope Compact Array, towards water maser sites previously identified in the H2O southern Galactic Plane Survey (HOPS). Of the 540 masers identified in the single-dish observations of Walsh et al., we detect emission in all but 31 fields. We report on 2790 spectral features (maser spots), with brightnesses ranging from 0.06 to 576 Jy and with velocities ranging from -238.5 to +300.5 km s-1. These spectral features are grouped into 631 maser sites. We have compared the positions of these sites to the literature to associate the sites with astrophysical objects. We identify 433 (69 per cent) with star formation, 121 (19 per cent) with evolved stars and 77 (12 per cent) as unknown. We find that maser sites associated with evolved stars tend to have more maser spots and have smaller angular sizes than those associated with star formation. We present evidence that maser sites associated with evolved stars show an increased likelihood of having a velocity range between 15 and 35 km s-1 compared to other maser sites. Of the 31 non-detections, we conclude they were not detected due to intrinsic variability and confirm previous results showing that such variable masers tend to be weaker and have simpler spectra with fewer peaks.

  9. Trapping hop looper moths, Hypena humuli Harris (Lepidoptera: Erebidae), in hop yards in Washington State with acetic acid and 3-methyl-1-butanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop looper moths, Hypena humuli Harris, in commercial hop yards (Humulus lupulus L.) were captured in traps baited with a combination of acetic acid plus 3-methyl-1-butanol (AAMB). The two chemicals were synergistic in attracting hop looper moths; in a comparison of the lure chemicals, most moths we...

  10. Modulation of breast cancer cell survival by aromatase inhibiting hop (Humulus lupulus L.) flavonoids.

    PubMed

    Monteiro, Rosário; Faria, Ana; Azevedo, Isabel; Calhau, Conceição

    2007-01-01

    Hop flavonoids are being regarded as attractive molecules to prevent or treat certain forms of cancer. Studies have focused mainly on xanthohumol, the most abundant prenylated chalcone existing in hops extract. However, during the production of beer, or after its ingestion, xanthohumol originates different metabolites, among which isoxanthohumol and 8-prenylnaringenin. The aim of this work was to study the effect of the prenylflavonoids xanthohumol, isoxanthohumol and 8-prenylnaringenin on the breast cancer Sk-Br-3 cell line proliferation, apoptosis and activity of the enzyme aromatase (estrogen synthase). Aromatase activity was determined by a tritiated water assay, cell proliferation was assessed by [(3)H]thymidine incorporation, sulforhodamine B protein measurement and Ki-67 immunostaining and apoptosis was determined by TUNEL. Our results show that all tested prenylflavonoids were able to inhibit aromatase activity and thus, estrogen formation. Additionally, breast cancer cell line proliferation was decreased and apoptosis induced by all three compounds. The presence of 17beta-estradiol in treatment medium was able to revert the effect of the prenylflavonoids on cellular proliferation. These observations strengthen the idea that hop flavonoids may have anti-breast cancer effects and shed new light on a possible mechanism of action by which these effects occur, namely through their ability to decrease estrogen synthesis. PMID:17643984

  11. Non-adiabatic dynamics around a conical intersection with surface-hopping coupled coherent states

    NASA Astrophysics Data System (ADS)

    Humeniuk, Alexander; Mitrić, Roland

    2016-06-01

    A surface-hopping extension of the coupled coherent states-method [D. Shalashilin and M. Child, Chem. Phys. 304, 103-120 (2004)] for simulating non-adiabatic dynamics with quantum effects of the nuclei is put forward. The time-dependent Schrödinger equation for the motion of the nuclei is solved in a moving basis set. The basis set is guided by classical trajectories, which can hop stochastically between different electronic potential energy surfaces. The non-adiabatic transitions are modelled by a modified version of Tully's fewest switches algorithm. The trajectories consist of Gaussians in the phase space of the nuclei (coherent states) combined with amplitudes for an electronic wave function. The time-dependent matrix elements between different coherent states determine the amplitude of each trajectory in the total multistate wave function; the diagonal matrix elements determine the hopping probabilities and gradients. In this way, both interference effects and non-adiabatic transitions can be described in a very compact fashion, leading to the exact solution if convergence with respect to the number of trajectories is achieved and the potential energy surfaces are known globally. The method is tested on a 2D model for a conical intersection [A. Ferretti, J. Chem. Phys. 104, 5517 (1996)], where a nuclear wavepacket encircles the point of degeneracy between two potential energy surfaces and interferes with itself. These interference effects are absent in classical trajectory-based molecular dynamics but can be fully incorpo rated if trajectories are replaced by surface hopping coupled coherent states.

  12. Non-adiabatic dynamics around a conical intersection with surface-hopping coupled coherent states.

    PubMed

    Humeniuk, Alexander; Mitrić, Roland

    2016-06-21

    A surface-hopping extension of the coupled coherent states-method [D. Shalashilin and M. Child, Chem. Phys. 304, 103-120 (2004)] for simulating non-adiabatic dynamics with quantum effects of the nuclei is put forward. The time-dependent Schrödinger equation for the motion of the nuclei is solved in a moving basis set. The basis set is guided by classical trajectories, which can hop stochastically between different electronic potential energy surfaces. The non-adiabatic transitions are modelled by a modified version of Tully's fewest switches algorithm. The trajectories consist of Gaussians in the phase space of the nuclei (coherent states) combined with amplitudes for an electronic wave function. The time-dependent matrix elements between different coherent states determine the amplitude of each trajectory in the total multistate wave function; the diagonal matrix elements determine the hopping probabilities and gradients. In this way, both interference effects and non-adiabatic transitions can be described in a very compact fashion, leading to the exact solution if convergence with respect to the number of trajectories is achieved and the potential energy surfaces are known globally. The method is tested on a 2D model for a conical intersection [A. Ferretti, J. Chem. Phys. 104, 5517 (1996)], where a nuclear wavepacket encircles the point of degeneracy between two potential energy surfaces and interferes with itself. These interference effects are absent in classical trajectory-based molecular dynamics but can be fully incorpo rated if trajectories are replaced by surface hopping coupled coherent states. PMID:27334155

  13. Family-Based Hip-Hop to Health: Outcome Results

    PubMed Central

    Fitzgibbon, M. L.; Stolley, M. R.; Schiffer, L.; Kong, A.; Braunschweig, C. L.; Gomez-Perez, S. L.; Odoms-Young, A.; Van Horn, L.; Christoffel, K. Kaufer; Dyer, A. R.

    2012-01-01

    This pilot study tested the feasibility of Family-Based Hip-Hop to Health, a school-based obesity prevention intervention for 3–5 year old Latino children and their parents, and estimated its effectiveness in producing smaller average changes in body mass index at one year follow-up. Four Head Start preschools administered through the Chicago Public Schools were randomly assigned to receive a Family-Based Intervention (FBI) or a General Health intervention (GHI). Parents signed consent forms for 147 of the 157 children enrolled. Both the school-based and family-based components of the intervention were feasible, but attendance for the parent intervention sessions was low. Contrary to expectations, a downtrend in BMI Z score was observed in both the intervention and control groups. While the data reflect a downward trend in obesity among these young Hispanic children, obesity rates remained higher at one-year follow-up (15%) than those reported by the National Health and Nutrition Examination Survey (2009–2010) for 2–5 year old children (12.1%). Developing evidence-based strategies for obesity prevention among Hispanic families remains a challenge. PMID:23532990

  14. Non-invasive Genotyping of Helicobacter pylori cagA, vacA, and hopQ from Asymptomatic Children

    PubMed Central

    Sicinschi, Liviu A.; Correa, Pelayo; Bravo, Luis E.; Peek, Richard M.; Wilson, Keith T.; Loh, John T.; Yepez, Maria C.; Gold, Benjamin D.; Thompson, Dexter T.; Cover, Timothy L.; Schneider, Barbara G.

    2011-01-01

    Background H. pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim: to genotype cagA, hopQ and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, in order to avoid selection bias resulting from endoscopy. Methods H. pylori status of 86 asymptomatic children was assessed by 13C-Urea Breath Test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ and vacA genes were amplified from stool DNA samples and sequenced. Results UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA positive children. Of the children's DNA samples which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA-positivity and vacA s1 genotypes (P<0.0001). Conclusions Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype. PMID:22404439

  15. Multi-hop teleportation based on W state and EPR pairs

    NASA Astrophysics Data System (ADS)

    Hai-Tao, Zhan; Xu-Tao, Yu; Pei-Ying, Xiong; Zai-Chen, Zhang

    2016-05-01

    Multi-hop teleportation has significant value due to long-distance delivery of quantum information. Many studies about multi-hop teleportation are based on Bell pairs, partially entangled pairs or W state. The possibility of multi-hop teleportation constituted by partially entangled pairs relates to the number of nodes. The possibility of multi-hop teleportation constituted by double W states is after n-hop teleportation. In this paper, a multi-hop teleportation scheme based on W state and EPR pairs is presented and proved. The successful possibility of quantum information transmitted hop by hop through intermediate nodes is deduced. The possibility of successful transmission is after n-hop teleportation. Project supported by the National Natural Science Foundation of China (Grant No. 61571105), the Prospective Future Network Project of Jiangsu Province, China (Grant No. BY2013095-1-18), and the Independent Project of State Key Laboratory of Millimeter Waves, China (Grant No. Z201504).

  16. From "They" Science to "Our" Science: Hip Hop Epistemology in STEAM Education

    NASA Astrophysics Data System (ADS)

    Dolberry, Maurice E.

    Hip hop has moved from being considered a type of music into being understood as a culture in which a prominent type of music originates. Hip hop culture has a philosophy and epistemological constructs as well. This study analyzed those constructs to determine how conceptions of science factor in hip hop worldviews. Pedagogical models in culturally responsive teaching and Science, Technology, Engineering, Arts, and Mathematics (STEAM) education were also examined to discern their philosophical connections with hip hop culture. These connections were used to create two theoretical models. The first one, Hip Hop Science, described how scientific thought functions in hip hop culture. The second model, Hip Hop STEAM Pedagogy, proposes how hip hop culture can inform STEAM teaching practices. The study began by using Critical Race Theory to create a theoretical framework proposing how the two theoretical models could be derived from the philosophical and pedagogical concepts. Content analysis and narrative inquiry were used to analyze data collected from scholarly texts, hip hop songs, and interviews with hip hop-responsive educators. The data from these sources were used initially to assess the adequacy of the proposed theoretical framework, and subsequently to improve its viability. Four overlapping themes emerged from the data analyses, including hip hop-resistance to formal education; how hip hop culture informs pedagogical practice in hip hop-responsive classrooms; conceptions of knowledge and reality that shape how hip hoppers conduct scientific inquiry; and hip hop-based philosophies of effective teaching for hip hoppers as a marginalized cultural group. The findings indicate that there are unique connections between hip hop epistemology, sciencemindedness, and pedagogical practices in STEAM education. The revised theoretical framework clarified the nature of these connections, and supported claims from prior research that hip hop culture provides viable sites of

  17. Topological Anderson insulator induced by inter-cell hopping disorder

    SciTech Connect

    Lv, Shu-Hui; Song, Juntao Li, Yu-Xian

    2013-11-14

    We have studied in detail the influence of same-orbit and different-orbit hopping disorders in HgTe/CdTe quantum wells. Intriguingly, similar to the behavior of the on-site Anderson disorder, a phase transition from a topologically trivial phase to a topological phase is induced at a proper strength of the same-orbit hopping disorder. For different-orbit hopping disorder, however, the phase transition does not occur. The results have been analytically verified by using effective medium theory. A consistent conclusion can be obtained by comparing phase diagrams, conductance, and conductance fluctuations. In addition, the influence of Rashba spin-orbit interaction (RSOI) on the system has been studied for different types of disorder, and the RSOI shows different influence on topological phase at different disorders. The topological phase induced by same-orbit hopping disorder is more robust against the RSOI than that induced by on-site Anderson disorder. For different-orbit hopping disorder, no matter whether the RSOI is included or not, the phase transition does not occur. The results indicate, whether or not the topological Anderson insulator can be observed depends on a competition between the different types of the disorder as well as the strength of the RSOI in a system.

  18. Surface hopping simulation of vibrational predissociation of methanol dimer

    NASA Astrophysics Data System (ADS)

    Jiang, Ruomu; Sibert, Edwin L.

    2012-06-01

    The mixed quantum-classical surface hopping method is applied to the vibrational predissociation of methanol dimer, and the results are compared to more exact quantum calculations. Utilizing the vibrational SCF basis, the predissociation problem is cast into a curve crossing problem between dissociative and quasibound surfaces with different vibrational character. The varied features of the dissociative surfaces, arising from the large amplitude OH torsion, generate rich predissociation dynamics. The fewest switches surface hopping algorithm of Tully [J. Chem. Phys. 93, 1061 (1990), 10.1063/1.459170] is applied to both diabatic and adiabatic representations. The comparison affords new insight into the criterion for selecting the suitable representation. The adiabatic method's difficulty with low energy trajectories is highlighted. In the normal crossing case, the diabatic calculations yield good results, albeit showing its limitation in situations where tunneling is important. The quadratic scaling of the rates on coupling strength is confirmed. An interesting resonance behavior is identified and is dealt with using a simple decoherence scheme. For low lying dissociative surfaces that do not cross the quasibound surface, the diabatic method tends to overestimate the predissociation rate whereas the adiabatic method is qualitatively correct. Analysis reveals the major culprits involve Rabi-like oscillation, treatment of classically forbidden hops, and overcoherence. Improvements of the surface hopping results are achieved by adopting a few changes to the original surface hopping algorithms.

  19. Efros-Shklovskii variable range hopping conductivity without Coulomb gap

    NASA Astrophysics Data System (ADS)

    Chen, Tianran; Skinner, Brian

    In doped semiconductors and Coulomb glasses, in the limit of weak coupling, the electron conductivity primarily proceeds by phonon-assisted tunneling or hopping between different sites through the insulating gaps that separate them. Electron conduction can occur both through nearest-neighbor hopping and through cotunneling of electrons between distant sites via a chain of intermediate virtual states. In the presence of some disorder, the latter mechanism dominates at low temperatures, where the length of the hops grows to optimize the conductivity. This transport mechanism was introduced by Mott, and is called variable range hopping. When the Coulomb interaction between localized electrons is taken into account, it can be shown that at a sufficiently low temperature, variable range hopping conductivity obeys the Efros-Shklovskii (ES) law, which has been observed in a number of amorphous semiconductors and granular metal systems at low temperatures. ES conductivity has been long understood as the result of a soft, Coulomb gap at the Fermi level. However, such a theory overlooks the presence of spatial correlations between site energies and their possible effects on electrical conductivity. In this talk, we show both analytically and numerically that in systems where spatial correlations must be taken into account, ES conductivity may persist far outside the Coulomb gap, in contrast to conventional transport theory for doped semiconductors and Coulomb glasses where ES conductivity only occurs within the Coulomb gap.

  20. Cultivated Grapevines Represent a Symptomless Reservoir for the Transmission of Hop Stunt Viroid to Hop Crops: 15 Years of Evolutionary Analysis

    PubMed Central

    Kawaguchi-Ito, Yoko; Li, Shi-Fang; Tagawa, Masaya; Araki, Hiroyuki; Goshono, Masafumi; Yamamoto, Shingen; Tanaka, Mayumi; Narita, Masako; Tanaka, Kazuaki; Liu, Sheng-Xue; Shikata, Eishiro; Sano, Teruo

    2009-01-01

    Hop stunt was a mysterious disorder that first emerged in the 1940s in commercial hops in Japan. To investigate the origin of this disorder, we infected hops with natural Hop stunt viroid (HpSVd) isolates derived from four host species (hop, grapevine, plum and citrus), which except for hop represent possible sources of the ancestral viroid. These plants were maintained for 15 years, then analyzed the HpSVd variants present. Here we show that the variant originally found in cultivated grapevines gave rise to various combinations of mutations at positions 25, 26, 54, 193, and 281. However, upon prolonged infection, these variants underwent convergent evolution resulting in a limited number of adapted mutants. Some of them showed nucleotide sequences identical to those currently responsible for hop stunt epidemics in commercial hops in Japan, China, and the United States. Therefore, these results indicate that we have successfully reproduced the original process by which a natural HpSVd variant naturally introduced into cultivated hops was able to mutate into the HpSVd variants that are currently present in commercial hops. Furthermore, and importantly, we have identified cultivated grapevines as a symptomless reservoir in which HSVd can evolve and be transmitted to hop crops to cause epidemics. PMID:20041179

  1. Triple-Hop Distance as a Valid Predictor of Lower Limb Strength and Power

    PubMed Central

    Hamilton, R Tyler; Shultz, Sandra J; Schmitz, Randy J; Perrin, David H

    2008-01-01

    Context: Hop tests are functional tests that reportedly require strength, power, and postural stability to perform. The extent to which a triple-hop distance (THD) test measures each of these characteristics is relatively unknown. Objective: To determine the extent to which the THD predicts performance on clinical measures of power, strength, and balance in athletic individuals. Design: Within-subjects correlational study. Setting: Station-based, preseason screening of athletes. Patients or Other Participants: Forty National Collegiate Athletic Association Division I-AA men's and women's soccer student-athletes (20 women, 20 men; age  =  20.0 ± 1.4 years, height  =  172.8 ± 9.2 cm, mass  =  71.9 ± 8.9 kg). Intervention(s): As part of a comprehensive preseason screening of athletes, participants completed the Balance Error Scoring System (BESS) test, 3 trials each of the THD and vertical jump, and 5 repetitions each of concentric isokinetic quadriceps and hamstrings strength testing at 60°/s and 180°/s. Bivariate correlations and linear regression analyses determined the extent to which THD (cm) predicted each of the strength, power, and balance measures. Main Outcome Measure(s): Maximal vertical jump height (cm), total BESS error scores, and quadriceps (Quad60, Quad180) and hamstrings (Ham60, Ham180) isokinetic maximum peak torque (Nm) at 60°/s and 180°/s, respectively. Results: Triple-hop distance was a strong predictor of vertical jump height, explaining 69.5% of the variance (P < .01). THD also predicted 56.7% of the variance in Ham60 (P < .01), 55.5% of the variance in Ham180 (P < .01), 49.0% of the variance in Quad60 (P < .01), and 58.8% of the variance in Quad180 (P < .01). No relationships between THD and BESS scores were noted. Conclusions: Triple-hop distance is a useful clinical test to predict an athlete's lower extremity strength and power. Although THD was not a predictor of static balance, further research is needed to examine

  2. Carbon films embedded by nickel nanoparticles: fluctuation in hopping rate and variable-range hopping with respect to annealing temperature

    NASA Astrophysics Data System (ADS)

    Dalouji, Vali; Elahi, Smohammad; Solaymani, Shahram; Ghaderi, Atefeh; Elahi, Hossein

    2016-05-01

    In this work, the electrical properties of carbon-nickel films annealed at different temperatures (573, 773, 1073 and 1273 K) in the temperature range 15-300 K were investigated. The films were grown by radio frequency magnetron co-sputtering on quartz substrates at room temperature. The multiphonon hopping conduction mechanism is found to dominate the electrical transport in the temperature range 150-300 K. It can be seen that the room-temperature hopping rate (ΓRT) at 773 K has maximum value of 56.8 × 105 s-1. Our results of conductivity measurements at high temperature are in good agreement with strong carrier-lattice coupling model; on the other hand, the conductivity in the range 15-50 K is well described in terms of variable-range hopping (VRH) conduction mechanism. The localized state density around Fermi level N( E F) and the average hopping energy W hop at low temperature for the films annealed at 773 K have maximum value of 2.23 × 1023 (cm-3 eV-1) and minimum value of 9.74 × 10-4 eV, respectively.

  3. Experimental verification of hopping mechanism using permanent magnets for an asteroid rover at drop tower

    NASA Astrophysics Data System (ADS)

    Kurisu, Masamitsu; Yano, Hajime; Yoshimitsu, Tetsuo; Kubota, Takashi; Adachi, Tadashi; Kuroda, Yoji

    Verification of the hopping mechanism using permanent magnets by microgravity experiments at ZARM drop tower will be presented in this report. The mechanism, which is called HMPM (Hopping Mechanism with Permanent Magnets) was developed for a small asteroid exploration rover to replace with conventional locomotion mechanism such as wheels and crawlers. The main part of HMPM consists of three permanent magnets which are two stationary magnets and one movable magnet aligned between them. HMPM itself hops by utilizing the impact force generated when the movable magnet sticks to one of the stationary magnets. The features of HMPM are that the large impact force can be generated in spite of low-power consumption, and that it can be easily miniaturized and modularized. On the other hand, the weak point of HMPM is that the performance of the mechanism cannot be controlled directly, since the performance is decided by its design. Therefore, it is significant to evaluate the performance of HMPM before it is mounted on a flight model of rover. On the microgravity experiments at the drop tower, an imitation rover with 0.8kg weight is tested to hop with the operation of a prototype HMPM mounted on the rover. The prototype module weighs only 0.03kg with dimension 0.033 m in width, 0.046 m in height, and 0.012 m in depth, except the drive circuit and power source. Experimental results show the availability of HMPM. Also, the hopping performance of HMPM which is evaluated from the motion of rover recorded by cameras equipped inside the dropping capsule is compared with the estimated performance derived from the theoretical model. From the investigation, validity of the evaluation method based on the theoretical model is discussed. In order that the potential ability of HMPM is fully derived, optimal design of HMPM will require the evaluation method. The experiments at ZARM drop tower were accomplished based on the agreement on the Hayabusa-2 project by DLR-JAXA. And we received

  4. Hop (Humulus lupulus L.) Extract and 6-Prenylnaringenin Induce P450 1A1 Catalyzed Estrogen 2-Hydroxylation

    PubMed Central

    2016-01-01

    Humulus lupulus L. (hops) is a popular botanical dietary supplement used by women as a sleep aid and for postmenopausal symptom relief. In addition to its efficacy for menopausal symptoms, hops can also modulate the chemical estrogen carcinogenesis pathway and potentially protect women from breast cancer. In the present study, an enriched hop extract and the key bioactive compounds [6-prenylnarigenin (6-PN), 8-prenylnarigenin (8-PN), isoxanthohumol (IX), and xanthohumol (XH)] were tested for their effects on estrogen metabolism in breast cells (MCF-10A and MCF-7). The methoxyestrones (2-/4-MeOE1) were analyzed as biomarkers for the nontoxic P450 1A1 catalyzed 2-hydroxylation and the genotoxic P450 1B1 catalyzed 4-hydroxylation pathways, respectively. The results indicated that the hop extract and 6-PN preferentially induced the 2-hydroxylation pathway in both cell lines. 8-PN only showed slight up-regulation of metabolism in MCF-7 cells, whereas IX and XH did not have significant effects in either cell line. To further explore the influence of hops and its bioactive marker compounds on P450 1A1/1B1, mRNA expression and ethoxyresorufin O-dealkylase (EROD) activity were measured. The results correlated with the metabolism data and showed that hop extract and 6-PN preferentially enhanced P450 1A1 mRNA expression and increased P450 1A1/1B1 activity. The aryl hydrocarbon receptor (AhR) activation by the isolated compounds was tested using xenobiotic response element (XRE) luciferase construct transfected cells. 6-PN was found to be an AhR agonist that significantly induced XRE activation and inhibited 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced XRE activity. 6-PN mediated induction of EROD activity was also inhibited by the AhR antagonist CH223191. These data show that the hop extract and 6-PN preferentially enhance the nontoxic estrogen 2-hydroxylation pathway through AhR mediated up-regulation of P450 1A1, which further emphasizes the importance of

  5. Hop (Humulus lupulus L.) Extract and 6-Prenylnaringenin Induce P450 1A1 Catalyzed Estrogen 2-Hydroxylation.

    PubMed

    Wang, Shuai; Dunlap, Tareisha L; Howell, Caitlin E; Mbachu, Obinna C; Rue, Emily A; Phansalkar, Rasika; Chen, Shao-Nong; Pauli, Guido F; Dietz, Birgit M; Bolton, Judy L

    2016-07-18

    Humulus lupulus L. (hops) is a popular botanical dietary supplement used by women as a sleep aid and for postmenopausal symptom relief. In addition to its efficacy for menopausal symptoms, hops can also modulate the chemical estrogen carcinogenesis pathway and potentially protect women from breast cancer. In the present study, an enriched hop extract and the key bioactive compounds [6-prenylnarigenin (6-PN), 8-prenylnarigenin (8-PN), isoxanthohumol (IX), and xanthohumol (XH)] were tested for their effects on estrogen metabolism in breast cells (MCF-10A and MCF-7). The methoxyestrones (2-/4-MeOE1) were analyzed as biomarkers for the nontoxic P450 1A1 catalyzed 2-hydroxylation and the genotoxic P450 1B1 catalyzed 4-hydroxylation pathways, respectively. The results indicated that the hop extract and 6-PN preferentially induced the 2-hydroxylation pathway in both cell lines. 8-PN only showed slight up-regulation of metabolism in MCF-7 cells, whereas IX and XH did not have significant effects in either cell line. To further explore the influence of hops and its bioactive marker compounds on P450 1A1/1B1, mRNA expression and ethoxyresorufin O-dealkylase (EROD) activity were measured. The results correlated with the metabolism data and showed that hop extract and 6-PN preferentially enhanced P450 1A1 mRNA expression and increased P450 1A1/1B1 activity. The aryl hydrocarbon receptor (AhR) activation by the isolated compounds was tested using xenobiotic response element (XRE) luciferase construct transfected cells. 6-PN was found to be an AhR agonist that significantly induced XRE activation and inhibited 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced XRE activity. 6-PN mediated induction of EROD activity was also inhibited by the AhR antagonist CH223191. These data show that the hop extract and 6-PN preferentially enhance the nontoxic estrogen 2-hydroxylation pathway through AhR mediated up-regulation of P450 1A1, which further emphasizes the importance of

  6. Communication: Optimal parameters for basin-hopping global optimization based on Tsallis statistics

    SciTech Connect

    Shang, C. Wales, D. J.

    2014-08-21

    A fundamental problem associated with global optimization is the large free energy barrier for the corresponding solid-solid phase transitions for systems with multi-funnel energy landscapes. To address this issue we consider the Tsallis weight instead of the Boltzmann weight to define the acceptance ratio for basin-hopping global optimization. Benchmarks for atomic clusters show that using the optimal Tsallis weight can improve the efficiency by roughly a factor of two. We present a theory that connects the optimal parameters for the Tsallis weighting, and demonstrate that the predictions are verified for each of the test cases.

  7. Starting with Style: Toward a Second Wave of Hip-Hop Education Research and Practice

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2015-01-01

    One fundamental breakthrough in the field of hip-hop education in recent years is the shift from understanding hip-hop solely as content to understanding hip-hop also as aesthetic form. In this article, I chart the roots of this shift across disciplines and focus on what it might mean for the future of hip-hop education, pedagogy, and research in…

  8. Effect of light on hopping conduction in kesterite CZTS thin films

    NASA Astrophysics Data System (ADS)

    Ghediya, Prashant R.; Chaudhuri, Tapas K.; Ray, Jaymin R.

    2016-05-01

    Mott variable range hopping conduction in dip-coated CZTS thin films has been studied in the temperature range of 77 to 150 K in dark and under different light intensities. The films were basically p-type and photoconducting. Various hopping parameters such as, Mott characteristic temperature, density of states at Fermi level, hopping distance and hopping energy of the CZTS films were investigated for different light intensities.

  9. Repetitive Hops Induce Postactivation Potentiation in Triceps Surae as well as an Increase in the Jump Height of Subsequent Maximal Drop Jumps

    PubMed Central

    Bergmann, Julian; Kramer, Andreas; Gruber, Markus

    2013-01-01

    Postactivation potentiation (PAP) has been defined as the increase in twitch torque after a conditioning contraction. The present study aimed to investigate the effectiveness of hops as conditioning contractions to induce PAP and increase performance in subsequent maximal drop jumps. In addition, we wanted to test if and how PAP can contribute to increases in drop jump rebound height. Twelve participants performed 10 maximal two-legged hops as conditioning contractions. Twitch peak torques of triceps surae muscles were recorded before and after the conditioning hops. Then, subjects performed drop jumps with and without 10 conditioning hops before each drop jump. Recordings included ground reaction forces, ankle and knee angles and electromyographic activity in five leg muscles. In addition, efferent motoneuronal output during ground contact was estimated with V-wave stimulation. The analyses showed that after the conditioning hops, twitch peak torques of triceps surae muscles were 32% higher compared to baseline values (P < 0.01). Drop jumps performed after conditioning hops were significantly higher (12%, P < 0.05), but V-waves and EMG activity remained unchanged. The amount of PAP and the change in drop jump rebound height were positively correlated (r2 = 0.26, P < 0.05). These results provide evidence for PAP in triceps surae muscles induced by a bout of hops and indicate that PAP can contribute to the observed performance enhancements in subsequent drop jumps. The lack of change in EMG activity and V-wave amplitude suggests that the underlying mechanisms are more likely intramuscular than neural in origin. PMID:24147061

  10. "Deeper than Rap": Gifted Males and Their Relationship with Hip Hop Culture

    ERIC Educational Resources Information Center

    Callahan, J. Sean; Grantham, Tarek C.

    2012-01-01

    One would be hard-pressed to deny the impact that hip hop is having on gifted students. More specifically, because hip hop is a creative and exciting male-dominated culture, gifted males gravitate to hip hop culture. From the perspective of two Black men from two different generations, this article was inspired by discussions about the role of hip…

  11. Behind Beats and Rhymes: Working Class from a Hampton Roads Hip Hop Homeplace

    ERIC Educational Resources Information Center

    Durham, Aisha S.

    2009-01-01

    The film documentary titled "Hip Hop: beyond beats and rhymes" captures ongoing conversations among scholars, cultural critics, and hip hop insiders about the state of African Americans by interrogating distinct expressive forms associated with hip hop culture. Durham draws from two scenes to describe her memories as the researched underclass and…

  12. Beats, Rhymes, and Classroom Life: Hip-Hop Pedagogy and the Politics of Identity

    ERIC Educational Resources Information Center

    Hill, Marc Lamont

    2009-01-01

    For over a decade, educators have looked to capitalize on the appeal of hip-hop culture, sampling its language, techniques, and styles as a way of reaching out to students. But beyond a fashionable hipness, what does hip-hop have to offer our schools? In this revelatory new book, Marc Lamont Hill shows how a serious engagement with hip-hop culture…

  13. Wish to Live: The Hip-Hop Feminism Pedagogy Reader. Educational Psychology. Volume 3

    ERIC Educational Resources Information Center

    Brown, Ruth Nicole, Ed.; Kwakye, Chamara Jewel, Ed.

    2012-01-01

    "Wish To Live: The Hip-hop Feminism Pedagogy Reader" moves beyond the traditional understanding of the four elements of hip-hop culture--rapping, breakdancing, graffiti art, and deejaying--to articulate how hip-hop feminist scholarship can inform educational practices and spark, transform, encourage, and sustain local and global youth community…

  14. Sequential sampling for estimation and classification of the incidence of hop powdery mildew I: Leaf sampling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop powdery mildew (caused by Podosphaera macularis) is an important disease of hops (Humulus lupulus) in the Pacific Northwest. Sequential sampling models for estimation and classification of the incidence of powdery mildew on leaves of hop were developed based on the beta-binomial distribution, u...

  15. Precision QTL mapping of downy mildew resistance in Hop (Humulus lupulus L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop Downy mildew (DM) is an obligate parasite causing severe losses in hop if not controlled. Resistance to this pathogen is a primary goal for hop breeding programs. The objective of this study was to identify QTLs linked to DM resistance. Next-generation-sequencing was performed on a mapping po...

  16. Flipping the Misogynist Script: Gender, Agency, Hip Hop and Music Education

    ERIC Educational Resources Information Center

    Tobias, Evan S.

    2014-01-01

    Excluding Hip Hop culture and rap music from music education misses opportunities for addressing key aspects of popular culture, society, and students' lives. This article addresses intersections of Hip Hop, gender, and music education to forward potential Hip Hop praxis. After tracing related scholarship, I discuss and problematize…

  17. Hopping locomotion at different gravity: metabolism and mechanics in humans.

    PubMed

    Pavei, Gaspare; Minetti, Alberto E

    2016-05-15

    Previous literature on the effects of low gravity on the mechanics and energetics of human locomotion already dealt with walking, running, and skipping. The aim of the present study is to obtain a comprehensive view on that subject by including measurements of human hopping in simulated low gravity, a gait often adopted in many Apollo Missions and documented in NASA footage. Six subjects hopped at different speeds at terrestrial, Martian, and Lunar gravity on a treadmill while oxygen consumption and 3D body kinematic were sampled. Results clearly indicate that hopping is too metabolically expensive to be a sustainable locomotion on Earth but, similarly to skipping (and running), its economy greatly (more than ×10) increases at lower gravity. On the Moon, the metabolic cost of hopping becomes even lower than that of walking, skipping, and running, but the general finding is that gaits with very different economy on Earth share almost the same economy on the Moon. The mechanical reasons for such a decrease in cost are discussed in the paper. The present data, together with previous findings, will allow also to predict the aerobic traverse range/duration of astronauts when getting far from their base station on low gravity planets. PMID:26635350

  18. Chicano Hip-Hop as Interethnic Contact Zone

    ERIC Educational Resources Information Center

    McFarland, Pancho

    2008-01-01

    Hip-hop is an interethnic contact zone that allows for the creation of new expressive cultures and new identities for young people. Its openness derives in part from the wide range of expression and interpretation allowed in 182 "McFarland" African musics. Moving beyond the often stifling options offered by an earlier generation that focused on…

  19. Crossing the Lexicon: Anglicisms in the German Hip Hop Community

    ERIC Educational Resources Information Center

    Garley, Matthew E.

    2012-01-01

    The influence of English on German has been an ongoing subject of intense popular and academic interest in the German sphere. In order to better understand this language contact situation, this research project investigates anglicisms--instances of English language material in a German language context--in the German hip hop community, where the…

  20. Examining Hip-Hop as Culturally Relevant Pedagogy

    ERIC Educational Resources Information Center

    Kim, Jung; Pulido, Isaura

    2015-01-01

    Culturally relevant pedagogy is a framework that conceptualizes the process of student learning as contingent upon educators' deep understanding of students' cultural backgrounds to co-construct knowledge and develop academic skills. Concurrently, there are a growing number of studies that explore hip-hop as a culturally relevant curriculum for…

  1. Young Children Manifest Spiritualities in Their Hip-Hop Writing

    ERIC Educational Resources Information Center

    Norton, Nadjwa E. L.

    2014-01-01

    In this article, the author combines multicultural feminist critical theories with the voices of Black and Latina/Latino young spiritual children to extend culturally responsive teaching. The author illuminates how children use their hip-hop writing to construct themselves as people who communicate with God, choose spiritual content for their…

  2. Critical Hip Hop Pedagogy as a Form of Liberatory Praxis

    ERIC Educational Resources Information Center

    Akom, A. A.

    2009-01-01

    This article uses Paulo Freire's problem-posing method, youth participatory action research, and case study methodology to introduce an alternative instructional strategy called Critical Hip Hop Pedagogy (CHHP). This approach attempts to address deep-rooted ideologies to social inequities by creating a space in teacher education courses for…

  3. Photon assisted hopping conduction mechanism in Tl2SSe crystals

    NASA Astrophysics Data System (ADS)

    Qasrawi, A. F.; Ziqan, Abdelhalim M.; Jazzar, Suha Kh.; Gasanly, N. M.

    2015-02-01

    In this article, the powder X-ray diffraction data and the dark and the photo-excited electrical conduction parameters of Tl2SSe crystal are reported. The dark and photon excited electrical conduction in the tetragonal crystal are found to be dominated by thermionic emission assisted variable range hopping conduction (VRH). The dark Mott's VRH parameters representing by the degree of disorder (To), the density of localized states near the Fermi level (N (EF)), the average hopping range (R) and average hopping energy (W) exhibited wide tunability via incremental photon intensity. Particularly, while the dark values of T0 , W and R significantly decreased from 2.32 ×108 to 1.52 ×105 K, 114 to 18.25 meV and from 66.15 to 10.58 A°, respectively, the values of N (EF) increased from 7.23 ×1018 to 1.10 ×1022cm-3 /eV when the crystal was photo-excited with a 53.6 mW/cm2 light intensity. These variations in the hopping parameters via photon excitations are promisig for using the crystal in the fabrication of well controlled, widely tunable, low energy consuming and highly efficient electronic devices.

  4. Analytical methods for quantitation of prenylated flavonoids from hops

    PubMed Central

    Nikolić, Dejan; van Breemen, Richard B.

    2013-01-01

    The female flowers of hops (Humulus lupulus L.) are used as a flavoring agent in the brewing industry. There is growing interest in possible health benefits of hops, particularly as estrogenic and chemopreventive agents. Among the possible active constituents, most of the attention has focused on prenylated flavonoids, which can chemically be classified as prenylated chalcones and prenylated flavanones. Among chalcones, xanthohumol (XN) and desmethylxanthohumol (DMX) have been the most studied, while among flavanones, 8-prenylnaringenin (8-PN) and 6-prenylnaringenin (6-PN) have received the most attention. Because of the interest in medicinal properties of prenylated flavonoids, there is demand for accurate, reproducible and sensitive analytical methods to quantify these compounds in various matrices. Such methods are needed, for example, for quality control and standardization of hop extracts, measurement of the content of prenylated flavonoids in beer, and to determine pharmacokinetic properties of prenylated flavonoids in animals and humans. This review summarizes currently available analytical methods for quantitative analysis of the major prenylated flavonoids, with an emphasis on the LC-MS and LC-MS-MS methods and their recent applications to biomedical research on hops. This review covers all methods in which prenylated flavonoids have been measured, either as the primary analytes or as a part of a larger group of analytes. The review also discusses methodological issues relating to the quantitative analysis of these compounds regardless of the chosen analytical approach. PMID:24077106

  5. Powdery Mildew Resistant Hop Germplasm Release: 'Kazak 2000'

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A USDA-sponsored plant collecting expedition in collaboration with the Vavilov Institute of Plant Industry (VIR), St. Petersburg, Russian Federation, and the Aral Sea Experiment Station for Plant Genetic Resources, Chelkar Town, Kazakhstan, was conducted in the fall of 2000. Hop cones were collecte...

  6. Metazoan cell biology of the HOPS tethering complex

    PubMed Central

    Zlatic, Stephanie A; Tornieri, Karine; L'Hernault, Steven W

    2011-01-01

    Membrane fusion with vacuoles, the lysosome equivalent of the yeast Saccharomyces cerevisiae, is among the best understood membrane fusion events. Our precise understanding of this fusion machinery stems from powerful genetics and elegant in vitro reconstitution assays. Central to vacuolar membrane fusion is the multi-subunit tether the HO motypic fusion and Protein Sorting (HOPS) complex, a complex of proteins that organizes other necessary components of the fusion machinery. We lack a similarly detailed molecular understanding of membrane fusion with lysosomes or lysosome-related organelles in metazoans. However, it is likely that fundamental principles of how rabs, SNAREs and HOPS tethers work to fuse membranes with lysosomes and related organelles are conserved between Saccharomyces cerevisiae and metazoans. Here, we discuss emerging differences in the coat-dependent mechanisms that govern HOPS complex subcellular distribution between Saccharomyces cerevisiae and metazoans. These differences reside upstream of the membrane fusion event. We propose that the differences in how coats segregate class C Vps/HOPS tethers to organelles and domains of metazoan cells are adaptations to complex architectures that characterize metazoan cells such as those of neuronal and epithelial tissues. PMID:21922076

  7. Differential design for hopping in two species of wallabies.

    PubMed

    McGowan, C P; Baudinette, R V; Biewener, A A

    2008-06-01

    Hindlimb musculoskeletal anatomy and steady speed over ground hopping mechanics were compared in two species of macropod marsupials, tammar wallabies and yellow-footed rock wallabies (YFRW). These two species are relatively closely related and are of similar size and general body plan, yet they inhabit different environments with presumably different musculoskeletal demands. Tammar wallabies live in relatively flat, open habitat whereas yellow-footed rock wallabies inhabit steep cliff faces. The goal of this study was to explore musculoskeletal differences between tammar wallabies and yellow-footed rock wallabies and determine how these differences influence each species' hopping mechanics. We found the cross-sectional area of the combined ankle extensor tendons of yellow-footed rock wallabies was 13% greater than that of tammar wallabies. Both species experienced similar ankle joint moments during steady-speed hopping, however due to a lower mechanical advantage at this joint, tammar wallabies produced 26% more muscle force. Thus, during moderate speed hopping, yellow-footed rock wallabies operated with 38% higher tendon safety factors, while tammar wallabies were able to store 73% more elastic strain energy (2.18 J per leg vs. 1.26 J in YFRW). This likely reflects the differing demands of the environments inhabited by these two species, where selection for non-steady locomotor performance in rocky terrain likely requires trade-offs in locomotor economy. PMID:16861021

  8. 21 CFR 172.560 - Modified hop extract.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Modified hop extract. 172.560 Section 172.560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Flavoring Agents and Related Substances...

  9. 21 CFR 172.560 - Modified hop extract.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Modified hop extract. 172.560 Section 172.560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Flavoring Agents and Related Substances...

  10. Contribution of afferent feedback and descending drive to human hopping

    PubMed Central

    Zuur, Abraham T; Lundbye-Jensen, Jesper; Leukel, Christian; Taube, Wolfgang; Grey, Michael J; Gollhofer, Albert; Nielsen, Jens Bo; Gruber, Markus

    2010-01-01

    During hopping an early burst can be observed in the EMG from the soleus muscle starting about 45 ms after touch-down. It may be speculated that this early EMG burst is a stretch reflex response superimposed on activity from a supra-spinal origin. We hypothesised that if a stretch reflex indeed contributes to the early EMG burst, then advancing or delaying the touch-down without the subject's knowledge should similarly advance or delay the burst. This was indeed the case when touch-down was advanced or delayed by shifting the height of a programmable platform up or down between two hops and this resulted in a correspondent shift of the early EMG burst. Our second hypothesis was that the motor cortex contributes to the first EMG burst during hopping. If so, inhibition of the motor cortex would reduce the magnitude of the burst. By applying a low-intensity magnetic stimulus it was possible to inhibit the motor cortex and this resulted in a suppression of the early EMG burst. These results suggest that sensory feedback and descending drive from the motor cortex are integrated to drive the motor neuron pool during the early EMG burst in hopping. Thus, simple reflexes work in concert with higher order structures to produce this repetitive movement. PMID:20064857

  11. AFLP Discrimination of Wild American and Cultivated Hop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop breeding historically relied upon relatively simple selection techniques within established breeding lines. Relying on a narrow genetic base to address production problems may lead to a genetic bottleneck in breeding germplasm, and may limit a breeder's ability to select for new traits. The obje...

  12. Cryopreservation and maintenance of hop material in USDA germplasm collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Clonal Germplasm Repository (NCGR-Corvallis) is responsible for conservation of the hop (Humulus lupulus L.) genetic resources for the US Department of Agriculture (USDA), Agricultural Research Service (ARS). The collection includes 675 accessions representing 7 related taxa (species an...

  13. Metazoan cell biology of the HOPS tethering complex.

    PubMed

    Zlatic, Stephanie A; Tornieri, Karine; L'hernault, Steven W; Faundez, Victor

    2011-05-01

    Membrane fusion with vacuoles, the lysosome equivalent of the yeast Saccharomyces cerevisiae, is among the best understood membrane fusion events. Our precise understanding of this fusion machinery stems from powerful genetics and elegant in vitro reconstitution assays. Central to vacuolar membrane fusion is the multi-subunit tether the HO motypic fusion and Protein Sorting (HOPS) complex, a complex of proteins that organizes other necessary components of the fusion machinery. We lack a similarly detailed molecular understanding of membrane fusion with lysosomes or lysosome-related organelles in metazoans. However, it is likely that fundamental principles of how rabs, SNAREs and HOPS tethers work to fuse membranes with lysosomes and related organelles are conserved between Saccharomyces cerevisiae and metazoans. Here, we discuss emerging differences in the coat-dependent mechanisms that govern HOPS complex subcellular distribution between Saccharomyces cerevisiae and metazoans. These differences reside upstream of the membrane fusion event. We propose that the differences in how coats segregate class C Vps/HOPS tethers to organelles and domains of metazoan cells are adaptations to complex architectures that characterize metazoan cells such as those of neuronal and epithelial tissues. PMID:21922076

  14. Recent Progress in Surface Hopping: 2011-2015.

    PubMed

    Wang, Linjun; Akimov, Alexey; Prezhdo, Oleg V

    2016-06-01

    Developed 25 years ago, Tully's fewest switches surface hopping (FSSH) has proven to be the most popular approach for simulating quantum-classical dynamics in a broad variety of systems, ranging from the gas phase, to the liquid and solid phases, to biological and nanoscale materials. FSSH is widely adopted as the fundamental platform to introduce modifications as needed. Significant progress has been made recently to enhance the accuracy and efficiency of the surface hopping technique. Various limitations of the standard FSSH-associated with quantum nuclear effects, interference and decoherence, trivial or "unavoided" crossings, superexchange, and representation dependence-have been lifted. These advances are needed to allow one to treat many important phenomena in chemistry, physics, materials, and related disciplines. Examples include charge transport in extended systems such as organic solids, singlet fission in molecular aggregates, Auger-type exciton multiplication, recombination and relaxation in quantum dots and other nanoscale materials, Auger-assisted charge transfer, nonradiative luminescence quenching, and electron-hole recombination. This Perspective summarizes recent advances in the surface hopping formulation of nonadiabatic dynamics and provides an outlook on the future of surface hopping. PMID:27171314

  15. Analytical methods for quantitation of prenylated flavonoids from hops.

    PubMed

    Nikolić, Dejan; van Breemen, Richard B

    2013-01-01

    The female flowers of hops (Humulus lupulus L.) are used as a flavoring agent in the brewing industry. There is growing interest in possible health benefits of hops, particularly as estrogenic and chemopreventive agents. Among the possible active constituents, most of the attention has focused on prenylated flavonoids, which can chemically be classified as prenylated chalcones and prenylated flavanones. Among chalcones, xanthohumol (XN) and desmethylxanthohumol (DMX) have been the most studied, while among flavanones, 8-prenylnaringenin (8-PN) and 6-prenylnaringenin (6-PN) have received the most attention. Because of the interest in medicinal properties of prenylated flavonoids, there is demand for accurate, reproducible and sensitive analytical methods to quantify these compounds in various matrices. Such methods are needed, for example, for quality control and standardization of hop extracts, measurement of the content of prenylated flavonoids in beer, and to determine pharmacokinetic properties of prenylated flavonoids in animals and humans. This review summarizes currently available analytical methods for quantitative analysis of the major prenylated flavonoids, with an emphasis on the LC-MS and LC-MS-MS methods and their recent applications to biomedical research on hops. This review covers all methods in which prenylated flavonoids have been measured, either as the primary analytes or as a part of a larger group of analytes. The review also discusses methodological issues relating to the quantitative analysis of these compounds regardless of the chosen analytical approach. PMID:24077106

  16. Hopping Diffusion of Nanoparticles Subjected to Topological Constraints

    NASA Astrophysics Data System (ADS)

    Cai, Li-Heng; Panyukov, Sergey; Rubinstein, Michael

    2013-03-01

    We describe a novel hopping mechanism for diffusion of large non-sticky nanoparticles subjected to topological constraints in polymer solids (networks and gels) and entangled polymer liquids (melts and solutions). Probe particles with size larger than the mesh size of unentangled polymer networks (tube diameter of entangled polymer liquids) are trapped by the network (entanglement) cages at time scales longer than the relaxation time of the network (entanglement) strand. At long time scales, however, these particles can move further by hopping between neighboring confinement cages. This hopping is controlled by fluctuations of surrounding confinement cages, which could be large enough to allow particles to slip through. The terminal particle diffusion coefficient dominated by this hopping diffusion is appreciable for particles with size slightly larger than the network mesh size (tube diameter). Very large particles in polymer solids will be permanently trapped by local network cages, whereas they can still move in polymer liquids by waiting for entanglement cages to rearrange on the relaxation time scale of the liquids. We would like to acknowledge the financial support of NSF CHE-0911588, DMR-0907515, DMR-1121107, DMR-1122483, and CBET-0609087, NIH R01HL077546 and P50HL107168, and Cystic Fibrosis Foundation under grant RUBIN09XX0.

  17. Packet error probabilities in frequency-hopped spread spectrum packet radio networks. Markov frequency hopping patterns considered

    NASA Astrophysics Data System (ADS)

    Georgiopoulos, M.; Kazakos, P.

    1987-09-01

    We compute the packet error probability induced in a frequency-hopped spread spectrum packet radio network, which utilizes first order Markov frequency hopping patterns. The frequency spectrum is divided into q frequency bins and the packets are divided into M bytes each. Every user in the network sends each of the M bytes of his packet at a frequency bin, which is different from the frequency bin used by the previous byte, but equally likely to be any one of the remaining q-1 frequency bins (Markov frequency hopping patterns). Furthermore, different users in the network utilize statistically independent frequency hopping patterns. Provided that, K users have simultaneously transmitted their packets on the channel, and a receiver has locked on to one of these K packets, we present a method for the computation of P sub e (K) (i.e. the probability that this packet is incorrectly decoded). Furthermore, we present numerical results (i.e. P sub e (K) versus K) for various values of the multiple access interference K, when Reed Solomon (RS) codes are used for the encoding of packets. Finally, some useful comparisons, with the packet error probability induced, if we assume that the byte errors are independent, are made; based on these comparisons, we can easily evaluate the performance of our spread spectrum system.

  18. Communication: Proper treatment of classically forbidden electronic transitions significantly improves detailed balance in surface hopping.

    PubMed

    Sifain, Andrew E; Wang, Linjun; Prezhdo, Oleg V

    2016-06-01

    Surface hopping is the most popular method for nonadiabatic molecular dynamics. Many have reported that it does not rigorously attain detailed balance at thermal equilibrium, but does so approximately. We show that convergence to the Boltzmann populations is significantly improved when the nuclear velocity is reversed after a classically forbidden hop. The proposed prescription significantly reduces the total number of classically forbidden hops encountered along a trajectory, suggesting that some randomization in nuclear velocity is needed when classically forbidden hops constitute a large fraction of attempted hops. Our results are verified computationally using two- and three-level quantum subsystems, coupled to a classical bath undergoing Langevin dynamics. PMID:27276938

  19. The impact of hop bitter acid and polyphenol profiles on the perceived bitterness of beer.

    PubMed

    Oladokun, Olayide; Tarrega, Amparo; James, Sue; Smart, Katherine; Hort, Joanne; Cook, David

    2016-08-15

    Thirty-four commercial lager beers were analysed for their hop bitter acid, phenolic acid and polyphenol contents. Based on analytical data, it was evident that the beers had been produced using a range of different raw materials and hopping practices. Principal Components Analysis was used to select a sub-set of 10 beers that contained diverse concentrations of the analysed bitter compounds. These beers were appraised sensorially to determine the impacts of varying hop acid and polyphenolic profiles on perceived bitterness character. Beers high in polyphenol and hop acid contents were perceived as having 'harsh' and 'progressive' bitterness, whilst beers that had evidently been conventionally hopped were 'sharp' and 'instant' in their bitterness. Beers containing light-stable hop products (tetrahydro-iso-α-acids) were perceived as 'diminishing', 'rounded' and 'acidic' in bitterness. The hopping strategy adopted by brewers impacts on the nature, temporal profile and intensity of bitterness perception in beer. PMID:27006233

  20. Pagan Biology at the Halloween Hop

    ERIC Educational Resources Information Center

    Lock, Roger

    2011-01-01

    Send your pupils into the autumn term half-term holiday with a task that requires them to explore more about the biology associated with Halloween. This article offers a fun approach, with a pub quiz format based on bats, skeletons, pumpkins and witches, that is suitable for lessons following the end-of-topic test, for STEM clubs or for PTA…

  1. Fast frequency hopping codes applied to SAC optical CDMA network

    NASA Astrophysics Data System (ADS)

    Tseng, Shin-Pin

    2015-06-01

    This study designed a fast frequency hopping (FFH) code family suitable for application in spectral-amplitude-coding (SAC) optical code-division multiple-access (CDMA) networks. The FFH code family can effectively suppress the effects of multiuser interference and had its origin in the frequency hopping code family. Additional codes were developed as secure codewords for enhancing the security of the network. In considering the system cost and flexibility, simple optical encoders/decoders using fiber Bragg gratings (FBGs) and a set of optical securers using two arrayed-waveguide grating (AWG) demultiplexers (DeMUXs) were also constructed. Based on a Gaussian approximation, expressions for evaluating the bit error rate (BER) and spectral efficiency (SE) of SAC optical CDMA networks are presented. The results indicated that the proposed SAC optical CDMA network exhibited favorable performance.

  2. Nanowire-based thermoelectric ratchet in the hopping regime

    NASA Astrophysics Data System (ADS)

    Bosisio, Riccardo; Fleury, Geneviève; Pichard, Jean-Louis; Gorini, Cosimo

    2016-04-01

    We study a thermoelectric ratchet consisting of an array of disordered nanowires arranged in parallel on top of an insulating substrate and contacted asymmetrically to two electrodes. Transport is investigated in the Mott hopping regime, when localized electrons can propagate through the nanowires via thermally assisted hops. When the electronic temperature in the nanowires is different from the phononic one in the substrate, we show that a finite electrical current is generated even in the absence of driving forces between the electrodes. We discuss the device performance both as an energy harvester, when an excess heat from the substrate is converted into useful power, and as a refrigerator, when an external power is supplied to cool down the substrate.

  3. Mixed quantum-classical equilibrium in global flux surface hopping

    SciTech Connect

    Sifain, Andrew E.; Wang, Linjun; Prezhdo, Oleg V.

    2015-06-14

    Global flux surface hopping (GFSH) generalizes fewest switches surface hopping (FSSH)—one of the most popular approaches to nonadiabatic molecular dynamics—for processes exhibiting superexchange. We show that GFSH satisfies detailed balance and leads to thermodynamic equilibrium with accuracy similar to FSSH. This feature is particularly important when studying electron-vibrational relaxation and phonon-assisted transport. By studying the dynamics in a three-level quantum system coupled to a classical atom in contact with a classical bath, we demonstrate that both FSSH and GFSH achieve the Boltzmann state populations. Thermal equilibrium is attained significantly faster with GFSH, since it accurately represents the superexchange process. GFSH converges closer to the Boltzmann averages than FSSH and exhibits significantly smaller statistical errors.

  4. Trajectory surface-hopping study of methane photodissociation dynamics

    NASA Astrophysics Data System (ADS)

    Lodriguito, Maricris D.; Lendvay, György; Schatz, George C.

    2009-12-01

    We use the fewest switches nonadiabatic trajectory surface hopping approach to study the photodissociation of methane on its lowest singlet excited state potential surface (1 T12) at 122 nm, with emphasis on product state branching and energy partitioning. The trajectories and couplings are based on CASSCF(8,9) calculations with an aug-cc-pvdz basis set. We demonstrate that nonadiabatic dynamics is important to describe the dissociation processes. We find that CH3(X˜ A22″)+H and CH2(ã A11)+H2 are the major dissociation channels, as have been observed experimentally. CH3+H is mostly formed by direct dissociation that is accompanied by hopping to the ground state. CH2+H2 can either be formed by hopping to the ground state to give CH2(ã A11)+H2 or by adiabatic dissociation to CH2(b˜ B11)+H2. In the latter case, the CH2(b˜ B11) can then undergo internal conversion to the ground singlet state by Renner-Teller induced hopping. Less important dissociation mechanisms lead to CH2+H+H and to CH+H2+H. Intersystem crossing effects, which are not included, do not seem essential to describe the experimentally observed branching behavior. About 5% of trajectories involve a roaming atom mechanism which can eventually lead to formation of products in any of the dissociation channels. Branching fractions to give H and H2 are in good agreement with experiment, and the H atom translational energy distribution shows bimodal character which also matches observations.

  5. HPLC Analysis of alpha and beta Acids in Hops

    SciTech Connect

    Danenhower, Travis; Force, Leyna; Petersen, Kenneth; Betts, Thomas; Baker, Gary A

    2008-01-01

    Early in brewing history, a variety of herbs and spices (such as coriander, rosemary, yarrow, and bog myrtle) were used to flavor beer (1). It is evident, from the Bavarian Purity Law of 1516, that a major shift in beer flavoring occurred around the middle of the second millennium. This law declared that only three ingredients could be used to brew beer: barley, water, and hops (1), thus eliminating other spices from German beer. (The importance of yeast had not yet been uncovered.)

  6. Light-induced hopping conductivity in a transparent oxide

    NASA Astrophysics Data System (ADS)

    Medvedeva, J. E.; Freeman, A. J.; Bertoni, M. I.; Mason, T. O.

    2004-03-01

    Recently, Hayashi et al (K. Hayashi et al), Nature 419, 462 (2002) found a way to convert a transparent oxide into a persistent conductor using UV light. The simplicity of the insulator-conductor conversion (hydrogen annealing followed by UV irradiation) and the resulting drastic change in conductivity (by 10 orders of magnitude) makes this material an extremely attractive starting point for optoelectronic applications. Despite careful experimental studies, no definitive understanding has been reached on the underlying mechanism responsible for this new dramatic effect. Here we demonstrate that ab-initio calculations provide a detailed explanation of the experimental findings and reveal the origin of the light-induced conductivity. We (i) show that the charge transport, associated with photo-excitation of an electron from hydrogen, occurs by electron hopping, (ii) determine the exact paths for the carrier migration and (iii) derive the temperature behavior of the hopping conductivity. We predict the strong dependence of the transport on the particular hopping centers and their spatial arrangement which is confirmed by our measurements, and investigate the possibility of varying the conductivity by proper doping.

  7. Critical appraisal of the fewest switches algorithm for surface hopping.

    PubMed

    Granucci, Giovanni; Persico, Maurizio

    2007-04-01

    In this paper the authors address the problem of internal consistency in trajectory surface hopping methods, i.e., the requirement that the fraction of trajectories running on each electronic state equals the probabilities computed by the electronic time-dependent Schrodinger equation, after averaging over all trajectories. They derive a formula for the hopping probability in Tully's "fewest switches" spirit that would yield a rigorously consistent treatment. They show the relationship of Tully's widely used surface hopping algorithm with the "exact" prescription that cannot be applied when running each trajectory independently. They also bring out the connection of the consistency problem with the coherent propagation of the electronic wave function and the artifacts caused by coherent Rabi-type oscillations of the state probabilities in weak coupling regimes. A real molecule (azobenzene) and two ad hoc models serve as examples to illustrate the above theoretical arguments. Following a proposal by Truhlar's group [Zhu et al., J. Chem. Phys. 121, 7658 (2004) Zhu et al., J. Chem. Theory Comput. 1, 527 (2005)], they apply a decoherence correction to the state probabilities, in conjunction with Tully's algorithm, and they obtain satisfactory results in terms of internal consistency and of agreement with the outcomes of quantum wave packet calculations. PMID:17430023

  8. Variable-Range Hopping through Marginally Localized Phonons

    NASA Astrophysics Data System (ADS)

    Banerjee, Sumilan; Altman, Ehud

    2016-03-01

    We investigate the effect of coupling Anderson localized particles in one dimension to a system of marginally localized phonons having a symmetry protected delocalized mode at zero frequency. This situation is naturally realized for electrons coupled to phonons in a disordered nanowire as well as for ultracold fermions coupled to phonons of a superfluid in a one-dimensional disordered trap. To determine if the coupled system can be many-body localized we analyze the phonon-mediated hopping transport for both the weak and strong coupling regimes. We show that the usual variable-range hopping mechanism involving a low-order phonon process is ineffective at low temperature due to discreteness of the bath at the required energy. Instead, the system thermalizes through a many-body process involving exchange of a diverging number n ∝-log T of phonons in the low temperature limit. This effect leads to a highly singular prefactor to Mott's well-known formula and strongly suppresses the variable range hopping rate. Finally, we comment on possible implications of this physics in higher dimensional electron-phonon coupled systems.

  9. Hip-Hop(e): The Cultural Practice and Critical Pedagogy of International Hip-Hop. Adolescent Cultures, School, and Society. Volume 56

    ERIC Educational Resources Information Center

    Porfilio, Brad J., Ed.; Viola, Michael J., Ed.

    2012-01-01

    Illuminating hip-hop as an important cultural practice and a global social movement, this collaborative project highlights the emancipatory messages and cultural work generated by the organic intellectuals of global hip-hop. Contributors describe the social realities--globalization, migration, poverty, criminalization, and racism--youth are…

  10. Effects of Powdery Mildew Fungicide Programs on Twospotted Spider Mite (Acari: Tetranychidae), Hop Aphid (Homoptera: Aphididae), and Their Natural Enemies in Hop Yards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twospotted spider mite, Tetranychus urticae Koch (Acari:Tetranychidae), and hop aphid, Phorodon humuli (Schrank) (Homoptera:Aphidiae), are the most important arthropod pests of hop (Humulus lupulus L.) in the Northern Hemisphere. A potential barrier for greater adoption of conservation biological c...

  11. Iterative quantum-classical path integral with dynamically consistent state hopping

    NASA Astrophysics Data System (ADS)

    Walters, Peter L.; Makri, Nancy

    2016-01-01

    We investigate the convergence of iterative quantum-classical path integral calculations in sluggish environments strongly coupled to a quantum system. The number of classical trajectories, thus the computational cost, grows rapidly (exponentially, unless filtering techniques are employed) with the memory length included in the calculation. We argue that the choice of the (single) trajectory branch during the time preceding the memory interval can significantly affect the memory length required for convergence. At short times, the trajectory branch associated with the reactant state improves convergence by eliminating spurious memory. We also introduce an instantaneous population-based probabilistic scheme which introduces state-to-state hops in the retained pre-memory trajectory branch, and which is designed to choose primarily the trajectory branch associated with the reactant at early times, but to favor the product state more as the reaction progresses to completion. Test calculations show that the dynamically consistent state hopping scheme leads to accelerated convergence and a dramatic reduction of computational effort.

  12. Iterative quantum-classical path integral with dynamically consistent state hopping.

    PubMed

    Walters, Peter L; Makri, Nancy

    2016-01-28

    We investigate the convergence of iterative quantum-classical path integral calculations in sluggish environments strongly coupled to a quantum system. The number of classical trajectories, thus the computational cost, grows rapidly (exponentially, unless filtering techniques are employed) with the memory length included in the calculation. We argue that the choice of the (single) trajectory branch during the time preceding the memory interval can significantly affect the memory length required for convergence. At short times, the trajectory branch associated with the reactant state improves convergence by eliminating spurious memory. We also introduce an instantaneous population-based probabilistic scheme which introduces state-to-state hops in the retained pre-memory trajectory branch, and which is designed to choose primarily the trajectory branch associated with the reactant at early times, but to favor the product state more as the reaction progresses to completion. Test calculations show that the dynamically consistent state hopping scheme leads to accelerated convergence and a dramatic reduction of computational effort. PMID:26827203

  13. Elastic ankle exoskeletons reduce soleus muscle force but not work in human hopping.

    PubMed

    Farris, Dominic James; Robertson, Benjamin D; Sawicki, Gregory S

    2013-09-01

    Inspired by elastic energy storage and return in tendons of human leg muscle-tendon units (MTU), exoskeletons often place a spring in parallel with an MTU to assist the MTU. However, this might perturb the normally efficient MTU mechanics and actually increase active muscle mechanical work. This study tested the effects of elastic parallel assistance on MTU mechanics. Participants hopped with and without spring-loaded ankle exoskeletons that assisted plantar flexion. An inverse dynamics analysis, combined with in vivo ultrasound imaging of soleus fascicles and surface electromyography, was used to determine muscle-tendon mechanics and activations. Whole body net metabolic power was obtained from indirect calorimetry. When hopping with spring-loaded exoskeletons, soleus activation was reduced (30-70%) and so was the magnitude of soleus force (peak force reduced by 30%) and the average rate of soleus force generation (by 50%). Although forces were lower, average positive fascicle power remained unchanged, owing to increased fascicle excursion (+4-5 mm). Net metabolic power was reduced with exoskeleton assistance (19%). These findings highlighted that parallel assistance to a muscle with appreciable series elasticity may have some negative consequences, and that the metabolic cost associated with generating force may be more pronounced than the cost of doing work for these muscles. PMID:23788578

  14. Hop-Based Energy Aware Routing Algorithm for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Cho, Jinsung; Lee, Sungyoung; Chen, Kwang-Cheng; Lee, Young-Koo

    Energy efficient routing is one of the key design issues to prolong the lifetime of wireless sensor networks (WSNs) since sensor nodes can not be easily re-charged once they are deployed. During routing process, the routes with only few hops or with too many hops are not energy efficient. Hop-based routing algorithms can largely improve the energy efficiency of multi-hop routing in WSNs because they can determine the optimal hop number as well as the corresponding intermediate nodes during multi-hop routing process under medium or high density network. In this paper, we not only focus on studying the relationship between energy consumption and hop number from theoretical point of view but also provide a practical selection criterion of the sub-optimal hop number under practical sensor network so as to minimize the energy consumption. We extend the theoretical deduction of optimal hop number and propose our Hop-based Energy Aware Routing (HEAR) algorithm which is totally distributed and localized. Simulation results show that our HEAR algorithm can reduce the average energy consumption about 10 times compared to the direct transmission algorithm and 2 to 10 times than other algorithms like LEACH and HEED under various network topologies.

  15. Multi-Hop Link Capacity of Multi-Route Multi-Hop MRC Diversity for a Virtual Cellular Network

    NASA Astrophysics Data System (ADS)

    Daou, Imane; Kudoh, Eisuke; Adachi, Fumiyuki

    In virtual cellular network (VCN), proposed for high-speed mobile communications, the signal transmitted from a mobile terminal is received by some wireless ports distributed in each virtual cell and relayed to the central port that acts as a gateway to the core network. In this paper, we apply the multi-route MHMRC diversity in order to decrease the transmit power and increase the multi-hop link capacity. The transmit power, the interference power and the link capacity are evaluated for DS-CDMA multi-hop VCN by computer simulation. The multi-route MHMRC diversity can be applied to not only DS-CDMA but also other access schemes (i. e. MC-CDMA, OFDM, etc.).

  16. Hops (Humulus lupulus) inhibits Oxidative Estrogen Metabolism and Estrogen-Induced Malignant Transformation in Human Mammary Epithelial cells (MCF-10A)

    PubMed Central

    Madhubhani, L.P.; Hemachandra, P.; Esala, R.; Chandrasena, P.; Chen, Shao-Nong; Main, Matthew; Lankin, David C.; Scism, Robert A.; Dietz, Birgit M.; Pauli, Guido F.; Thatcher, Gregory R. J.; Bolton, Judy L.

    2011-01-01

    Long-term exposure to estrogens including those in traditional hormone replacement therapy (HRT) increases the risk of developing hormone-dependent cancers. As a result, women are turning to over-the-counter (OTC) botanical dietary supplements such as black cohosh (Cimicifuga racemosa) and hops (Humulus lupulus) as natural alternatives to HRT. The two major mechanisms which likely contribute to estrogen and/or HRT cancer risk are: the estrogen receptor (ER) mediated hormonal pathway; and, the chemical carcinogenesis pathway involving formation of estrogen quinones that damage DNA and proteins, hence initiating and promoting carcinogenesis. Since OTC botanical HRT alternatives are in widespread use they may have the potential for chemopreventive effects on estrogen carcinogenic pathways in vivo. Therefore the effect of OTC botanicals on estrogen-induced malignant transformation of MCF-10A cells was studied. Cytochrome P450 catalyzed hydroxylation of estradiol at the 4-position leads to an o-quinone believed to act as the proximal carcinogen. LC-MS/MS analysis of estradiol metabolites showed that 4-hydroxylation was inhibited by hops, whereas black cohosh was without effect. Estrogen-induced expression of CYP450 1B1 and CYP450 1A1 was attenuated by the hops extract. Two phenolic constituents of hops (xanthohumol, XH; and 8-prenylnaringenin, 8-PN) were tested: 8-PN was a potent inhibitor whereas XH had no effect. Finally, estrogen-induced malignant transformation of MCF-10A cells was observed to be significantly inhibited by hops (5 μg/mL) and 8-PN (50 nM). These data suggest that hops extracts possess cancer chemopreventive activity through attenuation of estrogen metabolism mediated by 8-PN. PMID:21997247

  17. Hops (Humulus lupulus) inhibits oxidative estrogen metabolism and estrogen-induced malignant transformation in human mammary epithelial cells (MCF-10A).

    PubMed

    Hemachandra, L P; Madhubhani, P; Chandrasena, R; Esala, P; Chen, Shao-Nong; Main, Matthew; Lankin, David C; Scism, Robert A; Dietz, Birgit M; Pauli, Guido F; Thatcher, Gregory R J; Bolton, Judy L

    2012-01-01

    Long-term exposure to estrogens including those in traditional hormone replacement therapy (HRT) increases the risk of developing hormone-dependent cancers. As a result, women are turning to over-the-counter (OTC) botanical dietary supplements, such as black cohosh (Cimicifuga racemosa) and hops (Humulus lupulus), as natural alternatives to HRT. The two major mechanisms which likely contribute to estrogen and/or HRT cancer risk are: the estrogen receptor-mediated hormonal pathway; and the chemical carcinogenesis pathway involving formation of estrogen quinones that damage DNA and proteins, hence initiating and promoting carcinogenesis. Because, OTC botanical HRT alternatives are in widespread use, they may have the potential for chemopreventive effects on estrogen carcinogenic pathways in vivo. Therefore, the effect of OTC botanicals on estrogen-induced malignant transformation of MCF-10A cells was studied. Cytochrome P450 catalyzed hydroxylation of estradiol at the 4-position leads to an o-quinone believed to act as the proximal carcinogen. Liquid chromatography/tandem mass spectrometry analysis of estradiol metabolites showed that 4-hydroxylation was inhibited by hops, whereas black cohosh was without effect. Estrogen-induced expression of CYP450 1B1 and CYP450 1A1 was attenuated by the hops extract. Two phenolic constituents of hops (xanthohumol, XH; 8-prenylnaringenin, 8-PN) were tested: 8-PN was a potent inhibitor, whereas XH had no effect. Finally, estrogen-induced malignant transformation of MCF-10A cells was observed to be significantly inhibited by hops (5 μg/mL) and 8-PN (50 nmol/L). These data suggest that hops extracts possess cancer chemopreventive activity through attenuation of estrogen metabolism mediated by 8-PN. PMID:21997247

  18. Polaron hopping in olivine phosphates studied by nuclear resonant scattering

    NASA Astrophysics Data System (ADS)

    Tracy, Sally June

    Valence fluctuations of Fe2+ and Fe3+ were studied in a solid solution of LixFePO4 by nuclear resonant forward scattering of synchrotron x rays while the sample was heated in a diamond-anvil pressure cell. The spectra acquired at different temperatures and pressures were analyzed for the frequencies of valence changes using the Blume-Tjon model of a system with a fluctuating Hamiltonian. These frequencies were analyzed to obtain activation energies and an activation volume for polaron hopping. There was a large suppression of hopping frequency with pressure, giving an anomalously large activation volume. This large, positive value is typical of ion diffusion, which indicates correlated motions of polarons, and Li+ ions that alter the dynamics of both. In a parallel study of NaxFePO4, the interplay between sodium ordering and electron mobility was investigated using a combination of synchrotron x-ray diffraction and nuclear resonant scattering. Conventional Mossbauer spectra were collected while the sample was heated in a resistive furnace. An analysis of the temperature evolution of the spectral shapes was used to identify the onset of fast electron hopping and determine the polaron hopping rate. Synchrotron x-ray diffraction measurements were carried out in the same temperature range. Reitveld analysis of the diffraction patterns was used to determine the temperature of sodium redistribution on the lattice. The diffraction analysis also provides new information about the phase stability of the system. The temperature evolution of the iron site occupancies from the Mossbauer measurements, combined with the synchrotron diffraction results give strong evidence for a relationship between the onset of fast electron dynamics and the redistribution of sodium in the lattice. Measurements of activation barriers for polaron hopping gave fundamental insights about the correlation between electronic carriers and mobile ions. This work established that polaron-ion interactions

  19. Imbalance in expression of hop (Humulus lupulus) chalcone synthase H1 and its regulators during hop stunt viroid pathogenesis.

    PubMed

    Füssy, Zoltán; Patzak, Josef; Stehlík, Jan; Matoušek, Jaroslav

    2013-05-01

    Viroid-derived small RNAs generated during hop stunt viroid (HSVd) pathogenesis may induce the symptoms found in the hop cultivar "Admiral", including observed shifts in phenylpropanoid metabolites and changes in petiole coloration. Using quantitative RT-PCR, we examined hop lupulin gland-specific genes that have been shown to be involved in phenylpropanoid metabolism, for altered expression in response to infection with two HSVd isolates, HSVd-g and CPFVd. Most notably, the expression of a gene encoding a key enzyme for phenylpropanoid synthesis, naringenin-chalcone synthase H1 (chs_H1), decreased up to 40-fold in infected samples. In addition, a marked decrease in the expression of HlbHLH2 and an increase in the expression of HlMyb3 were observed. These two genes encode transcription factors that form a ternary complex with HlWDR1 for chs_H1 promoter activation. In a transient expression assay, a decrease in the ternary complex potential to activate the chs_H1 promoter was observed upon the decrease of HlbHLH2 expression. In addition, targeting of the chs_H1 transcript by vd-sRNAs may contribute to these expression changes. Our data show that HSVd infection causes a significant imbalance in the expression of phenylpropanoid metabolite-affecting genes via a complex mechanism, possibly involving regulatory disorders and direct targeting by vd-sRNA. PMID:23395540

  20. Fast proton hopping detection in ice I{sub h} by quasi-elastic neutron scattering.

    SciTech Connect

    Presiado, I.; Lal, J.; Mamontov, E.; Kolesnikov, A. I.; Huppert, D.

    2011-01-01

    Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The hopping time strongly depends on the temperature of the sample, and the activation energy of a hopping step is 17 kJ/mol. The values of {tau}{sub hop} of the current experiment are in good agreement with calculated values derived from previous photochemical experiments, in which we found that the proton hopping time at T > 242 K is on the order of 200 fs, roughly 10 times shorter than in liquid water at room temperature.

  1. Fast Proton Hopping Detection in Ice Ih by Quasi-Elastic Neutron Scattering

    SciTech Connect

    Presiado, Itay; Lal, Jyotsana; Mamontov, Eugene; Kolesnikov, Alexander I; Huppert, Dan I

    2011-01-01

    Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The hopping time strongly depends on the temperature of the sample, and the activation energy of a hopping step is 17 kJ/mol. The values of {tau}{sub hop} of the current experiment are in good agreement with calculated values derived from previous photochemical experiments,(1) in which we found that the proton hopping time at T > 242 K is on the order of 200 fs, roughly 10 times shorter than in liquid water at room temperature.

  2. Decoherence and mode hopping in a magnetic tunnel junction based spin torque oscillator.

    PubMed

    Muduli, P K; Heinonen, O G; Akerman, Johan

    2012-05-18

    We discuss the coherence of magnetic oscillations in a magnetic tunnel junction based spin torque oscillator as a function of the external field angle. Time-frequency analysis shows mode hopping between distinct oscillator modes, which arises from linear and nonlinear couplings in the Landau-Lifshitz-Gilbert equation, analogous to mode hopping observed in semiconductor ring lasers. These couplings and, therefore, mode hopping are minimized near the current threshold for the antiparallel alignment of free-layer with reference layer magnetization. Away from the antiparallel alignment, mode hopping limits oscillator coherence. PMID:23003182

  3. Hip-hop as a resource for understanding the urban context

    NASA Astrophysics Data System (ADS)

    Brown, Bryan

    2010-06-01

    This review explores Edmin's "Science education for the hip-hop generation" by documenting how he frames hip-hop as a means to access urban student culture. He argues that hip-hop is more than a mere music genre, but rather a culture that provides young people with ways of connecting to the world. Two primary ideas emerged as central to his work. First, he contends that students develop communal relationships and collective identities based on the common experiences expressed in hip-hop. Second, he identifies how the conscious recognition of institutional oppression serves a central feature in urban schools. Emdin's rich, and personal call for a greater understanding of hip-hop culture provides the text with an unmatched strength. He skillfully uses personal narratives from his own experience as well as quotes and references from hip-hop songs to make the nuances of hip hop transparent to science educators. Conversely, the limitation of this text is found in its unfulfilled promise to provide pragmatic examples of how to engage in a hip-hop based science education. Emdin's work is ultimately valuable as it extends our current knowledge about urban students and hip-hop in meaningful ways.

  4. Studies of ECCM improvements for frequency-hopping CPFSK systems

    NASA Astrophysics Data System (ADS)

    Lee, J. S.; Miller, L. E.; French, R. H.

    1990-05-01

    The performance of frequency hopping CPFSK modulations (such as used in several Army radio systems) in the presence of worst case partial band noise jamming (WCPBNJ) is derived for both limiter-discriminator and differential detector forms of receiver. The transmitter is assumed to repeat the data L times on different hops, and the receiver combines the L chips for each data symbol in a way to mitigate the effects of the jamming. Hard-decision combining simply makes a binary decision on each chip, then a majority decision on the whole symbol; this limits a jammed chip to one vote. AGC combining weights each analog chip sample in inverse proportion to the received noise power and decides on the basis of the sum of weighted chip samples; jammed chips tend to be weighted less. Analysis and computations show that either form of ECM combining can produce a 27 dB gain against WCPBNJ, and with error-control coding, a 31 to 33 dB gain. Coding alone can give a 28 to 29 dB gain. Soft decoding of hard-decision diversity combining gives 1.4 dB more gain than hard decoding. It is also shown that, due to the spectral attenuation characteristics of the receiver's IF filter, the effects of the transient phase difference between the incoming hopping waveform and the receiver's synthesizer are primarily confined to an interval of duration T + ts + tau, where T is the symbol duration (inverse of IF bandwidth), ts is the synthesizer switching time, and tau is the offset in synchronization between the received signal and the receiver's synthesizer.

  5. Disposition of hop prenylflavonoids in human breast tissue

    PubMed Central

    Bolca, Selin; Li, Jinghu; Nikolic, Dejan; Roche, Nathalie; Blondeel, Phillip; Possemiers, Sam; De Keukeleire, Denis; Bracke, Marc; Heyerick, Arne; van Breemen, Richard B.; Depypere, Herman

    2013-01-01

    Hop-derived products may contain xanthohumol (XN), isoxanthohumol (IX), and the potent phytoestrogen 8-prenylnaringenin (8-PN). To evaluate the potential health effects of these prenylflavonoids on breast tissue, their concentration, nature of metabolites, and biodistribution were assessed and compared to 17β-estradiol (E2) exposure. In this dietary intervention study, women were randomly allocated to hop (n=11; 2.04 mg XN, 1.20 mg IX, and 0.1 mg 8-PN per supplement) or control (n=10). After a run-in of ≥4d, 3 supplements were taken daily during 5d preceding an aesthetic breast reduction. Blood and breast biopsies were analyzed using HPLC-ESI-MS/MS. Upon hop administration, XN and IX concentrations ranged between 0.72–17.65 nmol/L and 3.30–31.50 nmol/L, and between 0.26– 5.14 pmol/g and 1.16–83.67 pmol/g in hydrolyzed serum and breast tissue, respectively. 8-PN however, was only detected in samples of moderate and strong 8-PN producers (0.43–7.06 nmol/L and 0.78–4.83 pmol/g). Phase I metabolism appeared to be minor (~10%), whereas extensive glucuronidation was observed (>90%). Total prenylflavonoids showed a breast adipose/glandular tissue distribution of 38/62 and their derived E2-equivalents were negligible compared to E2 in adipose (384.6±118.8 fmol/g, P=0.009) and glandular (241.6±93.1 fmol/g, P<0.001) tissue, respectively. Consequently, low doses of prenylflavonoids are unlikely to elicit estrogenic responses in breast tissue. PMID:20486208

  6. Disposition of hop prenylflavonoids in human breast tissue.

    PubMed

    Bolca, Selin; Li, Jinghu; Nikolic, Dejan; Roche, Nathalie; Blondeel, Phillip; Possemiers, Sam; De Keukeleire, Denis; Bracke, Marc; Heyerick, Arne; van Breemen, Richard B; Depypere, Herman

    2010-07-01

    Hop-derived products may contain xanthohumol (XN), isoxanthohumol (IX), and the potent phytoestrogen 8-prenylnaringenin (8-PN). To evaluate the potential health effects of these prenylflavonoids on breast tissue, their concentration, nature of metabolites, and biodistribution were assessed and compared with 17beta-estradiol (E(2)) exposure. In this dietary intervention study, women were randomly allocated to hop (n=11; 2.04 mg XN, 1.20 mg IX, and 0.1 mg 8-PN per supplement) or control (n=10). After a run-in of >or=4 days, three supplements were taken daily for 5 days preceding an aesthetic breast reduction. Blood and breast biopsies were analyzed using HPLC-ESI-MS/MS. Upon hop administration, XN and IX concentrations ranged between 0.72 and 17.65 nmol/L and 3.30 and 31.50 nmol/L, and between 0.26 and 5.14 pmol/g and 1.16 and 83.67 pmol/g in hydrolyzed serum and breast tissue, respectively. 8-PN however, was only detected in samples of moderate and strong 8-PN producers (0.43-7.06 nmol/L and 0.78-4.83 pmol/g). Phase I metabolism appeared to be minor (approximately 10%), whereas extensive glucuronidation was observed (> 90%). Total prenylflavonoids showed a breast adipose/glandular tissue distribution of 38/62 and their derived E(2)-equivalents were negligible compared with E(2) in adipose (384.6+/-118.8 fmol/g, p=0.009) and glandular (241.6+/-93.1 fmol/g, p<0.001) tissue, respectively. Consequently, low doses of prenylflavonoids are unlikely to elicit estrogenic responses in breast tissue. PMID:20486208

  7. Semiclassical quantization of nonadiabatic systems with hopping periodic orbits.

    PubMed

    Fujii, Mikiya; Yamashita, Koichi

    2015-02-21

    We present a semiclassical quantization condition, i.e., quantum-classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller's trace formula to a nonadiabatic form. The quantum-classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics. PMID:25701999

  8. Structure and Charge Hopping Dynamics in Green Rust

    SciTech Connect

    Wander, Matthew C; Rosso, Kevin M; Schoonen, Martin A

    2007-08-02

    Green rust is a family of mixed-valent iron phases formed by a number of abiotic and biotic processes under alkaline suboxic conditions. Due to its high Fe2+ content, green rust is a potentially important phase for pollution remediation by serving as a powerful electron donor for reductive transformation. However, mechanisms of oxidation of this material are poorly understood. An essential component of the green rust structure is a mixed-valent brucite-like Fe(OH)2 sheet comprised of a two dimensional network of edge-sharing iron octahedra. Room temperature Mössbauer spectra show a characteristic signature for intermediate valence on the iron atoms in this sheet, indicative of a Fe2+-Fe3+ valence interchange reaction faster than approximately 107 s-1. Using Fe(OH)2 as structural analogue for reduced green rust, we performed Hartree-Fock calculations on periodic slab models and cluster representations to determine the structure and hopping mobility of Fe3+ hole polarons in this material, providing a first principles assessment of the Fe2+-Fe3+ valence interchange reaction rate. The calculations show that among three possible symmetry unique iron-to-iron hops within a sheet, a hop to next-nearest neighbors at an intermediate distance of 5.6 Å is the fastest. The predicted rate is on the order of 1012 s-1 consistent the Mössbauer-based constraint. All other possibilities, including hopping across interlayer spaces, are predicted to be slower than 107 s-1. Collectively, the findings suggest the possibility of hole self-diffusion along sheets as a mechanism for regeneration of lattice Fe2+ sites, consistent with previous experimental observations of edge-inward progressive oxidation of green rust.

  9. Compressive detection of frequency-hopping spread spectrum signals

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Marcellin, Michael W.; Goodman, Nathan A.; Bilgin, Ali

    2013-05-01

    In this paper, compressive detection strategies for FHSS signals are introduced. Rapid switching of the carrier frequency among many channels using a pseudorandom sequence makes detection of FHSS signals challenging. The conventional approach to detect these signals is to rapidly scan small segments of the spectrum sequentially. However, such a scanner has the inherent risk of never overlapping with the transmitted signal depending on factors such as rate of hopping and scanning. In this paper, we propose compressive detection strategies that sample the full spectrum in a compressive manner. Theory and simulations are presented to illustrate the benefits of the proposed framework.

  10. Compressive sensing of frequency-hopping spread spectrum signals

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Kim, Yookyung; Goodman, Nathan A.; Ashok, Amit; Bilgin, Ali

    2012-06-01

    In this paper, compressive sensing strategies for interception of Frequency-Hopping Spread Spectrum (FHSS) signals are introduced. Rapid switching of the carrier among many frequency channels using a pseudorandom sequence (unknown to the eavesdropper) makes FHSS signals dicult to intercept. The conventional approach to intercept FHSS signals necessitates capturing of all frequency channels and, thus, requires the Analog-to-Digital Converters (ADCs) to sample at very high rates. Using the fact that the FHSS signals have sparse instanta- neous spectra, we propose compressive sensing strategies for their interception. The proposed techniques are validated using Gaussian Frequency-Shift Keying (GFSK) modulated FHSS signals as dened by the Bluetooth specication.

  11. Magnetic effect on hopping rate of electrons in organic semiconductors

    NASA Astrophysics Data System (ADS)

    Zhao, Junqing; Wang, Ting; Zhang, Meisheng; Zhang, Ningyu; Pang, Yantao; Li, Luyan; Ji, Yanju; Zhuang, Shidong; Mao, Jinhua; Wang, Huilin

    2013-10-01

    Considering effects of molecular vibration (ω0), hyperfine interaction (J), spin energy split, spin flip, and spin entanglement (η) of electron with nucleus on the hopping rate of electrons in organic semiconductors, we establish a model to calculate organic magnetoresistance (OMAR) within magnetic field B of 1 T. The results show that the effect of spin energy split is minimal, ω0 influences the gradient of OMAR to B in high field, J influences the OMAR in low field, the spin flip shows impact mainly in low field, η affects OMAR throughout the considered magnetic field and turns the high-field OMAR from positive to negative value.

  12. Semiclassical quantization of nonadiabatic systems with hopping periodic orbits

    SciTech Connect

    Fujii, Mikiya Yamashita, Koichi

    2015-02-21

    We present a semiclassical quantization condition, i.e., quantum–classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller’s trace formula to a nonadiabatic form. The quantum–classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics.

  13. High-Speed On-Board Data Processing for Science Instruments: HOPS

    NASA Technical Reports Server (NTRS)

    Beyon, Jeffrey

    2015-01-01

    The project called High-Speed On-Board Data Processing for Science Instruments (HOPS) has been funded by NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) program during April, 2012 â€" April, 2015. HOPS is an enabler for science missions with extremely high data processing rates. In this three-year effort of HOPS, Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) and 3-D Winds were of interest in particular. As for ASCENDS, HOPS replaces time domain data processing with frequency domain processing while making the real-time on-board data processing possible. As for 3-D Winds, HOPS offers real-time high-resolution wind profiling with 4,096-point fast Fourier transform (FFT). HOPS is adaptable with quick turn-around time. Since HOPS offers reusable user-friendly computational elements, its FPGA IP Core can be modified for a shorter development period if the algorithm changes. The FPGA and memory bandwidth of HOPS is 20 GB/sec while the typical maximum processor-to-SDRAM bandwidth of the commercial radiation tolerant high-end processors is about 130-150 MB/sec. The inter-board communication bandwidth of HOPS is 4 GB/sec while the effective processor-to-cPCI bandwidth of commercial radiation tolerant high-end boards is about 50-75 MB/sec. Also, HOPS offers VHDL cores for the easy and efficient implementation of ASCENDS and 3-D Winds, and other similar algorithms. A general overview of the 3-year development of HOPS is the goal of this presentation.

  14. The Association Between Knee Confidence and Muscle Power, Hop Performance, and Postural Orientation in People With Anterior Cruciate Ligament Injury.

    PubMed

    Ageberg, Eva; Roos, Ewa M

    2016-06-01

    Study Design Cross-sectional. Background The association between muscle function and lack of knee confidence in people with anterior cruciate ligament (ACL) injury has not been well investigated. Such knowledge would help in the design of training programs for this population. Objective To investigate associations between self-reported knee confidence and muscle function in patients with ACL injury. Methods Cross-sectional data from 54 patients (mean age, 30 years; range, 20-39 years; 28% women) with ACL injury, treated with training and reconstructive surgery (n = 36) or training only (n = 18), were assessed 3 ± 1 years after injury. Univariate and multivariable ordinal regression analyses were conducted to test the association between the patient's knee confidence (question 3 from the Knee injury and Osteoarthritis Outcome Score as the dependent variable) and performance on tests of muscle power, hop performance, and postural orientation (test for substitution patterns score) as independent variables (absolute value on the injured leg, and limb symmetry index [LSI; injured leg/uninjured leg × 100] or absolute difference between the injured and uninjured legs). Results Sixteen patients reported no trouble with lack of knee confidence, 24 mild trouble, 10 moderate trouble, and 4 severe or extreme trouble. Univariate analyses revealed significant associations between worse knee confidence and lower (worse) LSIs for knee extension power, vertical jump, and side hop, and worse test for substitution patterns scores. In the multivariable analysis, worse vertical jump LSI (P = .043) and worse side hop LSI (P = .012) significantly accounted for 25% of the variation in perceived knee confidence. Conclusion Between-leg differences during demanding tasks are associated with knee confidence in individuals with ACL injury. J Orthop Sports Phys Ther 2016;46(6):477-482. Epub 26 Apr 2016. doi:10.2519/jospt.2016.6374. PMID:27117728

  15. Intermediate tunnelling-hopping regime in DNA charge transport

    NASA Astrophysics Data System (ADS)

    Xiang, Limin; Palma, Julio L.; Bruot, Christopher; Mujica, Vladimiro; Ratner, Mark A.; Tao, Nongjian

    2015-03-01

    Charge transport in molecular systems, including DNA, is involved in many basic chemical and biological processes, and its understanding is critical if they are to be used in electronic devices. This important phenomenon is often described as either coherent tunnelling over a short distance or incoherent hopping over a long distance. Here, we show evidence of an intermediate regime where coherent and incoherent processes coexist in double-stranded DNA. We measure charge transport in single DNA molecules bridged to two electrodes as a function of DNA sequence and length. In general, the resistance of DNA increases linearly with length, as expected for incoherent hopping. However, for DNA sequences with stacked guanine-cytosine (GC) base pairs, a periodic oscillation is superimposed on the linear length dependence, indicating partial coherent transport. This result is supported by the finding of strong delocalization of the highest occupied molecular orbitals of GC by theoretical simulation and by modelling based on the Büttiker theory of partial coherent charge transport.

  16. Intermediate tunnelling-hopping regime in DNA charge transport.

    PubMed

    Xiang, Limin; Palma, Julio L; Bruot, Christopher; Mujica, Vladimiro; Ratner, Mark A; Tao, Nongjian

    2015-03-01

    Charge transport in molecular systems, including DNA, is involved in many basic chemical and biological processes, and its understanding is critical if they are to be used in electronic devices. This important phenomenon is often described as either coherent tunnelling over a short distance or incoherent hopping over a long distance. Here, we show evidence of an intermediate regime where coherent and incoherent processes coexist in double-stranded DNA. We measure charge transport in single DNA molecules bridged to two electrodes as a function of DNA sequence and length. In general, the resistance of DNA increases linearly with length, as expected for incoherent hopping. However, for DNA sequences with stacked guanine-cytosine (GC) base pairs, a periodic oscillation is superimposed on the linear length dependence, indicating partial coherent transport. This result is supported by the finding of strong delocalization of the highest occupied molecular orbitals of GC by theoretical simulation and by modelling based on the Büttiker theory of partial coherent charge transport. PMID:25698331

  17. Hops for Menopausal Vasomotor Symptoms: Mechanisms of Action.

    PubMed

    Abdi, Fatemeh; Mobedi, Hamid; Roozbeh, Nasibeh

    2016-08-01

    Menopause is a critical stage of women's life associated with various complaints and distresses. Vasomotor symptoms (VMS), such as hot flushes, night sweats, sleep disturbances, and fatigue, are the most common menopause symptoms affecting about 50% to 80% of middle-aged women. Obviously, these symptoms, resulting from estrogen deficiency during menopause, can exert negative effects on women's health and quality of life and thus require to be managed through approaches such as hormone replacement therapy (HRT). Many herbal treatments for menopause symptoms contain and its components such as 8-prenylnaringenin, 6-PN, isoxanthohumol and xanthohumol. Recent in-vivo studies have highlighted the ability of 8-prenylnaringenin to reduce serum-luteinizing hormone (LH) and follicle-stimulating hormone (FSH), to increase serum prolactin levels and uterine weight, and to induce vaginal hyperplastic epithelium. Previous research has shown that hops extract can strongly bind to both estrogen receptors, stimulate alkaline phosphatase activity in Ishikawa cells, and upregulate presenelin-2 and progesterone receptor mRNA in Ishikawa cells. Numerous clinical trials have documented significant reductions in the frequency of hot flushes following the administration of hop-containing preparations. Nevertheless, further clinical trials with larger sample size and longer follow-up are warranted to confirm such benefits. PMID:27617238

  18. Frequency hopping millimeter-wave reflectometry in ASDEX upgrade

    SciTech Connect

    Cupido, L.; Graca, S.; Conway, G. D.; Manso, M.; Serra, F.

    2006-10-15

    Millimeter-wave reflectometers for performing density fluctuations have traditionally used either tunable fixed frequency (heterodyne and homodyne) systems or multichannel fixed frequency arrangements. Only recently novel systems were brought into operation with the ability to hop from one frequency to another over a large bandwidth, during each plasma discharge, while retaining the quality of fixed frequency phase locked sources. The new broadband fast hopping millimeter-wave reflectometer incorporates frequency synthesizers for both plasma signal and local oscillators, and the receivers are heterodyne producing full phase/amplitude outputs. Two identical systems were recently installed in (ASDEX upgrade tokamak - IPP-MPG Germany) covering the Q band (33-50 GHz) and the V band (50-75 GHz). In the present article the system is described and the particular implementation on ASDEX, using monostatic antenna system, is presented showing the possibility of correlation studies in fully optimized antenna scenarios. With both Q and V channels in operation it was possible to devise several operation schemes that are described here and a result showing the radial localization of magnetohydrodynamic activity is also presented.

  19. Coding for frequency hopped spread spectrum satellite communications

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Li, G.; Blake, I. F.; Bhargava, V. K.; Chen, Q.

    1992-04-01

    The performance of fast frequency hopped spread spectrum systems with M-ary frequency shift keying and error correction coding under jamming conditions are analyzed. Ratio threshold diversity combining is used. The decoding scheme is error erasure decoding with metrics generated by the diversity combiner. The bit error probability of the system is computed and improvements offered by error correction coding are shown. The performance of several error correction codes is compared under different channel conditions. The notion of an arbitrarily varying channel (AVC) is discussed, including capacities of AVC's and a discrete memoryless channel, and two Gaussian AVC models are described. Coded performance of a slow frequency hopped differential phase shift keying (DPSK) system in presence of both additive white Gaussian noise and tone jamming is studied. The error correlation due to DPSK demodulation and the effect of tone jamming are considered in evaluating the block and decoded error probabilities. The effect of interleaving on system performance is addressed. A nearly optimum code rate for a length 255 Reed-Solomon code is derived for systems employing interleaving. Finally, a parallel approach to the design of universal receivers for unknown and time-varying channels is applied to DPSK systems in the presence of noise and tone interference.

  20. Sequential vortex hopping in an array of artificial pinning centers

    SciTech Connect

    Keay, J. C.

    2010-02-24

    We use low-temperature magnetic force microscopy (MFM) to study the hopping motion of vortices in an array of artificial pinning centers (APCs). The array consists of nanoscale holes etched in a niobium thin film by Ar-ion sputtering through an anodic aluminum-oxide template. Variable-temperature magnetometry shows a transition temperature of 7.1 K and an enhancement of the magnetization up to the third matching field at 5 K. Using MFM with attractive and repulsive tip-vortex interaction, we measure the vortex-pinning strength and investigate the motion of individual vortices in the APC array. The depinning force for individual vortices at low field ranged from 0.7 to 1.2 pN. The motion of individual vortices was found to be reproducible and consistent with movement between adjacent holes in the film. The movements are repeatable but the sequence of hops depends on the scan direction. This asymmetry in the motion indicates nonuniform local pinning, a consequence of array disorder and hole-size variation.

  1. HOPS 383: AN OUTBURSTING CLASS 0 PROTOSTAR IN ORION

    SciTech Connect

    Safron, Emily J.; Megeath, S. Thomas; Booker, Joseph; Fischer, William J.; Furlan, Elise; Rebull, Luisa M.; Stutz, Amelia M.; Stanke, Thomas; Billot, Nicolas; Tobin, John J.; Ali, Babar; Allen, Lori E.; Watson, Dan M.; Wilson, T. L.

    2015-02-10

    We report the dramatic mid-infrared brightening between 2004 and 2006 of Herschel Orion Protostar Survey (HOPS) 383, a deeply embedded protostar adjacent to NGC 1977 in Orion. By 2008, the source became a factor of 35 brighter at 24 μm with a brightness increase also apparent at 4.5 μm. The outburst is also detected in the submillimeter by comparing APEX/SABOCA to SCUBA data, and a scattered-light nebula appeared in NEWFIRM K{sub s} imaging. The post-outburst spectral energy distribution indicates a Class 0 source with a dense envelope and a luminosity between 6 and 14 L{sub ⊙}. Post-outburst time-series mid- and far-infrared photometry show no long-term fading and variability at the 18% level between 2009 and 2012. HOPS 383 is the first outbursting Class 0 object discovered, pointing to the importance of episodic accretion at early stages in the star formation process. Its dramatic rise and lack of fading over a 6 year period hint that it may be similar to FU Ori outbursts, although the luminosity appears to be significantly smaller than the canonical luminosities of such objects.

  2. Hops for Menopausal Vasomotor Symptoms: Mechanisms of Action

    PubMed Central

    Abdi, Fatemeh; Mobedi, Hamid

    2016-01-01

    Menopause is a critical stage of women's life associated with various complaints and distresses. Vasomotor symptoms (VMS), such as hot flushes, night sweats, sleep disturbances, and fatigue, are the most common menopause symptoms affecting about 50% to 80% of middle-aged women. Obviously, these symptoms, resulting from estrogen deficiency during menopause, can exert negative effects on women's health and quality of life and thus require to be managed through approaches such as hormone replacement therapy (HRT). Many herbal treatments for menopause symptoms contain and its components such as 8-prenylnaringenin, 6-PN, isoxanthohumol and xanthohumol. Recent in-vivo studies have highlighted the ability of 8-prenylnaringenin to reduce serum-luteinizing hormone (LH) and follicle-stimulating hormone (FSH), to increase serum prolactin levels and uterine weight, and to induce vaginal hyperplastic epithelium. Previous research has shown that hops extract can strongly bind to both estrogen receptors, stimulate alkaline phosphatase activity in Ishikawa cells, and upregulate presenelin-2 and progesterone receptor mRNA in Ishikawa cells. Numerous clinical trials have documented significant reductions in the frequency of hot flushes following the administration of hop-containing preparations. Nevertheless, further clinical trials with larger sample size and longer follow-up are warranted to confirm such benefits. PMID:27617238

  3. Three-dimensional numerical simulations for activated hopping conduction

    NASA Astrophysics Data System (ADS)

    Zimmerman, Dan S.; Shegelski, Mark R. A.

    1988-07-01

    We model hopping conduction in a three-dimensional, lightly doped compensated semiconductor using a Miller-Abrahams-type resistor network. A flat density of states of width Δɛ is used. We work with the full expression for the resistances instead of the T-->0 asymptotic form usually employed. We report the first detailed numerical calculations of the overall resistance of a three-dimensional resistor network using this full expression. We find a temperature regime where the hopping conduction has a ratio of activation energy to bandwidth ɛ~3=ɛ3/Δɛ=0.217(8). This value agrees with the analytically determined value calculated by Shegelski and Barrie (SB), and disagrees with results reported by other workers, thereby validating SB's analytic theory and their claim that the full expression for the resistor network should be used in calculations of ɛ~3. An investigation is made into the dependence of ɛ~3 on Δɛ we find, in qualitative agreement with SB, that ɛ~3 decreases with Δɛ and we present improved values for ɛ~3 as a function of Δɛ.

  4. Post-Civil Rights Music; or Why Hip Hop Is Dominant

    ERIC Educational Resources Information Center

    Walcott, Rinaldo

    2005-01-01

    Hip hop is the most multicultural of popular musical forms--all races and ethnicities are involved. Simultaneously hip hop is also the most racialized, and indeed the most blackened, musical form of individuals' times. How did this happen and why should it be of interests to music scholars? In this short essay, the author attempts to suggest that…

  5. Characterization of the Mammalian CORVET and HOPS Complexes and Their Modular Restructuring for Endosome Specificity.

    PubMed

    van der Kant, Rik; Jonker, Caspar T H; Wijdeven, Ruud H; Bakker, Jeroen; Janssen, Lennert; Klumperman, Judith; Neefjes, Jacques

    2015-12-18

    Trafficking of cargo through the endosomal system depends on endosomal fusion events mediated by SNARE proteins, Rab-GTPases, and multisubunit tethering complexes. The CORVET and HOPS tethering complexes, respectively, regulate early and late endosomal tethering and have been characterized in detail in yeast where their sequential membrane targeting and assembly is well understood. Mammalian CORVET and HOPS subunits significantly differ from their yeast homologues, and novel proteins with high homology to CORVET/HOPS subunits have evolved. However, an analysis of the molecular interactions between these subunits in mammals is lacking. Here, we provide a detailed analysis of interactions within the mammalian CORVET and HOPS as well as an additional endosomal-targeting complex (VIPAS39-VPS33B) that does not exist in yeast. We show that core interactions within CORVET and HOPS are largely conserved but that the membrane-targeting module in HOPS has significantly changed to accommodate binding to mammalian-specific RAB7 interacting lysosomal protein (RILP). Arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome-associated mutations in VPS33B selectively disrupt recruitment to late endosomes by RILP or binding to its partner VIPAS39. Within the shared core of CORVET/HOPS, we find that VPS11 acts as a molecular switch that binds either CORVET-specific TGFBRAP1 or HOPS-specific VPS39/RILP thereby allowing selective targeting of these tethering complexes to early or late endosomes to time fusion events in the endo/lysosomal pathway. PMID:26463206

  6. Trends in German Hip Hop Music and Its Usefulness for the Classroom

    ERIC Educational Resources Information Center

    Schmidt, Johannes

    2008-01-01

    German hip hop music has proved productive, especially since 2000 when rap in Germany experienced something like a first crisis. As a response, German hip hop artists and record labels have ventured off in several different directions including other musical genres, different topics, and new approaches to German rap. This article discusses the…

  7. New outbreaks of verticillium wilt on Hop in Oregon caused by nonlethal verticillium albo-atrum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2006 and 2007, new outbreaks of Verticillium wilt on hop were detected on two farms in Oregon. Verticillium pathogens vary in their virulence to hop; some strains cause minor damage but others can kill susceptible cultivars. Studies were conducted to determine the identity of the Verticillium sp...

  8. Supporting Communication and Argumentation in Urban Science Education: Hip-Hop, the Battle, and the Cypher

    ERIC Educational Resources Information Center

    Emdin, Christopher

    2011-01-01

    This paper is based on an exploration of communication and argumentation in urban science classrooms, and provides a description of the role that Hip-hop based education plays in supporting these major components of science education. The paper is intended to both support, and critique conventional uses of hip-hop based education, and provide…

  9. Hegemony, Hope, and the Harlem Renaissance: Taking Hip Hop Culture Seriously

    ERIC Educational Resources Information Center

    Price, Robert J., Jr.

    2005-01-01

    Adult education instructors and administrators, who typically are not members of the hip hop generation, often have little knowledge and understanding of rap music (also known as gangsta rap) and hip hop culture, and consequently do not take the black popular cultural phenomenon seriously as it relates to adult education. Adult educators,…

  10. Proust, Hip-Hop, and Death in First-Year Composition

    ERIC Educational Resources Information Center

    Sirc, Geoffrey

    2006-01-01

    Hip-hop as content in a first-year writing course offers students a powerful way to connect with their worlds. This article draws on Marcel Proust as a kind of rhyme to legitimate hip-hop as a substantive expressive medium to achieve artistry in writing.

  11. Sampling Practices and Social Spaces: Exploring a Hip-Hop Approach to Higher Education

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2010-01-01

    Much more than a musical genre, hip-hop culture exists as an animating force in the lives of many young adults. This article looks beyond the moral concerns often associated with rap music to explore how hip-hop as a larger set of expressions and practices implicates the educational experiences, activities, and approaches for students. The article…

  12. Representin': Drawing from Hip-Hop and Urban Youth Culture to Inform Teacher Education

    ERIC Educational Resources Information Center

    Irizarry, Jason G.

    2009-01-01

    The potential of drawing from urban youth culture, and hip-hop more specifically, to serve as a bridge to the standard curriculum has been well documented. However, the richness and potential benefits of hip-hop are more far-reaching and present significant implications for teacher education and professional development efforts as well. This…

  13. Student Perceptions of the Hip Hop Culture's Influence on the Undergraduate Experience

    ERIC Educational Resources Information Center

    Wessel, Roger D.; Wallaert, Kerry A.

    2011-01-01

    This study sought to determine how identification and engagement with the hip hop culture influenced the educational experiences of undergraduate students at a Midwestern, predominately White university by interviewing 11 students who self-identified as being immersed in the hip hop culture. Through a qualitative, phenomenological investigation,…

  14. Hip-Hop, Social Justice, and Environmental Education: Toward a Critical Ecological Literacy

    ERIC Educational Resources Information Center

    Cermak, Michael J.

    2012-01-01

    This essay describes an educational initiative that used environmentally themed (green) hip-hop to stimulate learning in an environmental science classroom. Students were then challenged to compose their own green hip-hop and their lyrics demonstrated skills that have thematic consistency around what is called a Critical Ecological Literacy (CEL).…

  15. Wounded Healing: Forming a Storytelling Community in Hip-Hop Lit

    ERIC Educational Resources Information Center

    Hill, Marc Lamont

    2009-01-01

    Background/Context: Over the past 5 years, there has been a growing body of scholarship that examines the intersections of hip-hop culture and classroom pedagogy. Although recent scholarship has persuasively demonstrated the classroom potential of hip-hop texts for promoting student engagement, scaffolding sanctioned forms of knowledge, and…

  16. Deal with It We Must: Education, Social Justice, and the Curriculum of Hip Hop Culture

    ERIC Educational Resources Information Center

    Baszile, Denise Taliaferro

    2009-01-01

    Although hip hop culture has been one of the most significant urban youth movements over the last three decades, it has only recently gained attention within the educational literature as a force to be reckoned with. And even then, much of the literature seeks to understand how hip hop can be used to engage students in the official school…

  17. Hip-Hop and a Hybrid Text in a Postsecondary English Class

    ERIC Educational Resources Information Center

    Sanchez, Deborah M.

    2010-01-01

    This study explores the epistemology present in hip-hop music and its reflection in the writing of one African American student in a postsecondary transitional English class. An integration of hip-hop and academic literacy practices in the student's essay challenges the supremacy of a "standard" academic English and deficit perspectives about…

  18. Hip-Hop Culture in College Students' Lives: Elements, Embodiment, and Higher Edutainment

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2011-01-01

    College campuses have become rich sites of hip-hop culture and knowledge production. Despite the attention that campus personnel and researchers have paid to student life, the field of higher education has often misunderstood the ways that hip-hop culture exists in college students' lives. Based upon in-depth interviews, observations of…

  19. Teaching Controversal Topics in Contemporary German Culture through Hip-Hop

    ERIC Educational Resources Information Center

    Putnam, Michael

    2006-01-01

    This article discusses the rich cultural resources embedded with German hip-hop music and its potential impact on the foreign language classroom. In particular, this article suggests methods and materials for integrating German hip-hop music in the discussion of recent controversial cultural events and attitudes in German after the "Wende."

  20. Empowerment in Context: Lessons from Hip-Hop Culture for Social Work Practice

    ERIC Educational Resources Information Center

    Travis, Raphael, Jr.; Deepak, Anne

    2011-01-01

    Hip-hop culture can be used as a conduit to enhanced cultural competence and practice skills through the individual and community empowerment framework. This framework is introduced as a tool for direct practice that allows social workers to understand the competing messages within hip-hop culture and how they may impact youths by promoting or…

  1. We Can Relate: Hip-Hop Culture, Critical Pedagogy, and the Secondary Classroom

    ERIC Educational Resources Information Center

    Stovall, David

    2006-01-01

    This article seeks to locate hip-hop in the realm of popular culture in education. Through the use of song lyrics, the author suggests the use of rap music to provide context for the humanities and social sciences in secondary curriculum. Using a theoretical and practical lens, the article argues for the use of hip-hop and other elements of…

  2. Polish Hip Hop as a Form of Multiliteracies and Situated Learning

    ERIC Educational Resources Information Center

    Torrence, Michael L.

    2009-01-01

    The purpose of this ethnographic study was to examine Hip Hop in Poland through the lens of multiliteracies and situated learning. This analysis is concerned with the transmission of Hip Hop to and within Wroclaw, Poland, and its acculturation and assimilation in Wroclaw, Poland. Further, this study seeks to illustrate how professional Polish Hip…

  3. Hip-Hop's Influence on the Identity Development of Black Female College Students: A Literature Review

    ERIC Educational Resources Information Center

    Henry, Wilma J.; West, Nicole M.; Jackson, Andrea

    2010-01-01

    This article explores unique issues regarding the effects of hip-hop culture on the identity development of young Black female college students. Through the lenses of womanist and Black feminist perspectives, the intersecting impact of race and gender are reviewed within the context of the competing influences of hip-hop on Black female identity.…

  4. Affiliation and Alienation: Hip-Hop, Rap, and Urban Science Education

    ERIC Educational Resources Information Center

    Emdin, Christopher

    2010-01-01

    The critiques of rap artists and other participants in hip-hop culture provide data for teachers and researchers to investigate the attitudes of US urban youth towards schooling. This study explores the complex relationships between hip-hop and science education by examining how rap lyrics project beliefs about schooling, the relevance of existing…

  5. Helicobacter pylori hopQ alleles (type I and II) in gastric cancer

    PubMed Central

    LEYLABADLO, HAMED EBRAHIMZADEH; YEKANI, MINA; GHOTASLOU, REZA

    2016-01-01

    The Helicobacter pylori (H. pylori) outer membrane protein (HopQ) of is one of the proteins involved in bacterial adherence to gastric mucosa and has been suggested to have a role in the virulence of H. pylori. The aim of the present study was to determine the association between H. pylori virulence types I and II hopQ genotypes and patients with different gastrointestinal diseases. A polymerase chain reaction-based assay was used to determine the presence of type I and type II hopQ genes in 88 H. pylori strains isolated from H. pylori-infected patients. Of the total 88 H. pylori isolates, type I and type II hopQ alleles were detected in 52 (59.1%) and 36 (40.9%), respectively. A significant association was found between type I hopQ gene and gastric cancer [odds ratio, 2.3; 95% confidence interval (CI), 1.3–4.1] and gastric ulcers (odds ratio, 2.5; 95% CI, 1.4–4.3). A significant association was also identified between the type II hopQ gene and gastric cancer (odds ratio, 2.4; 95% CI, 1.1–3.0). The association between hopQ type I and hopQ type II genotypes and clinical status suggest that these genes may be helpful in the universal prediction of specific disease risks. PMID:27123254

  6. Language, Localization, and the Real: Hip-Hop and the Global Spread of Authenticity

    ERIC Educational Resources Information Center

    Pennycook, Alastair

    2007-01-01

    This article addresses the relationship between the call for authenticity, its relocalization in other contexts, and the use of English. Hip-hop forces us to confront some of the conflictual discourses of authenticity and locality, from those that insist that African American hip-hop is the only real variety and that all other forms are…

  7. Predicting Offspring Performance in Hop (Humulus lupulus L.) Using AFLP Markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pedigree and combining ability information for male and female hop accessions is limited and choice of breeding parents remains guesswork. This studies’ objective was to determine if AFLP markers could be used to predict offspring performance in hop. AFLP assays were used to estimate genetic dista...

  8. Day Care Hopping: Stabilizing Day Care Options for Low-Income Mothers through Subsidies

    ERIC Educational Resources Information Center

    Drentea, Patricia; Durham, Suzanne; Mwaria, Mercie; Norman, Emily; Xi, Juan

    2004-01-01

    We examined how to allocate a subsidy to low-income women that would stabilize children in day care at a Young Women's Christian Association (YWCA). The subsidy is to alleviate day care hopping (i.e. when parents move from day care to day care) leaving unpaid tuitions at each place. Day care hopping is really a survival strategy for the working…

  9. Dynamic jamming effects on code synchronization of frequency-hop spread-spectrum

    NASA Astrophysics Data System (ADS)

    van Grouw, M. G.; Wickert, M. A.

    1989-06-01

    A general scheme for the code synchronization of Frequency-Hop Spread-Spectrum (FHSS) is presented. Synchronization performance is observed in the presence of channel dynamics and is characterized by mean synchronization time and mean time to loss of lock. A fixed-threshold multiple-dwell synchronization scheme is shown to adequately mitigate the effects of random hop jamming.

  10. Association between Helicobacter pylori hopQI genotypes and human gastric cancer risk.

    PubMed

    Kazemi, E; Kahrizi, D; Moradi, M T; Sohrabi, M; Amini, S; Mousavi, S A R; Yari, K

    2016-01-01

    The Helicobacter pylori use a number of mechanisms to survive in the stomach lumen and can lead to gastritis and reduction in stomach acid secretion. It has been found that the risk of developing gastric carcinoma is associated to heterogeneity of H. pylori virulence factors such as HopQ. The HopQ is one of the outer membrane proteins involved in bacterial adherence to gastric mucosa and has been suggested to also main role in the virulence of H. pylori. The purpose of the current study was to investigate the association between different H. pylori virulence hopQI (types I) genotyping and patients with gastroduodenal disorders. For this purpose 58 stomach biopsies of the patients with gastric cancer and 100 saliva samples from healthy and H. pylori infected individuals were collected and studied. Then genomic DNA was purified and PCR was done for desired gene via specific primers. The H. pylori infections were diagnosed using PCR for GlmM gene. Then frequencies of hopQI+ and hopQI- genotypes were determined in H. pylori infected cases. Statistical analysis showed that there were not significant differences between healthy and diseased ones for genotypes hopQI+ and hopQI-. Then the hopQI+ cannot be as a risk factor genotype for gastric cancer. PMID:26828979

  11. Electrically and optically detected spin echo of hopping carriers in organic semiconductors

    NASA Astrophysics Data System (ADS)

    Mkhitaryan, Vagharsh; Dobrovitski, Viatcheslav

    We develop a theory for electrically and optically detected primary (2-pulse) and stimulated (3-pulse) spin echo produced by the polaron pairs coupled to the nuclear spins in organic semiconductors. The theory employs fully quantum description of the nuclear and polaron spins, and explains how the structure of the echo signal (electron spin echo envelope modulation, ESEEM) depends on the statistics and rate of the polaron hopping. For the primary spin echo the envelope modulation is strong for slow hopping; both modulation amplitude and dephasing time T2 decrease with increasing hopping rate. As the hopping rate increases further, T2 starts to increase again due to motional narrowing, while the primary echo signal becomes exponential without modulation. The stimulated spin echo signal also shows strong envelope modulation for slow polaron hopping. For faster hopping the stimulated echo (unlike the primary echo) shows a modulation which does not disappear for fast hopping, and has the frequency of the nuclear Larmor precession. Besides describing the recent spin echo measurements in π-conjugated polymers, our work provides a way to directly determine the polaron hopping dynamics from the spin echo experiments. This work was supported by the Department of Energy-Basic Energy Sciences under Contract No. DE-AC02-07CH11358.

  12. Susceptibility of hop cultivars to downy mildew: associations with chemical characteristics and region of origin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop downy mildew is a yield limiting disease in many hop production regions of the world. In this research, 110 cultivars that are or were widely grown in the U.S., Europe, or Australasia were evaluated in western Oregon over three years for their reaction to the shoot infection phase of downy mild...

  13. Effects of hops (Humulus lupulus L.) extract on volatile fatty acid production by rumen bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: To determine the effects of hops extract, on in vitro volatile fatty acid (VFA) production by bovine rumen microorganisms. Methods and Results: When mixed rumen microbes were suspended in media containing carbohydrates, the initial rates of VFA production were suppressed by beta-acid rich hops...

  14. Antimicrobial activity of hop extracts against Listeria monocytogenes in media and in food.

    PubMed

    Larson, A E; Yu, R R; Lee, O A; Price, S; Haas, G J; Johnson, E A

    1996-12-01

    Growth of Listeria monocytogenes was inhibited in culture media and in certain foods by four hop extracts (I-IV) containing varying concentrations of alpha-and beta-acids. Extracts (II and III) containing the highest concentrations of beta-acids were inhibitory at 0.01 mg/l in trypticase soy broth. In food, these hop extracts showed varying magnitudes of inhibition. In coleslaw, hop extract III at 1 mg/g enhanced the rate of inactivation of L. monocytogenes Scott A. Hop extract II was inhibitory at 0.1 and 1 mg/ml in skim and 2% milk, and was inhibitory at 1 mg/ml in whole milk. Hop extract II was listericidal in cottage cheese at 0.1 to 3 g/kg. No inhibition of L. monocytogenes by hop extract III was observed in Camembert cheese. Overall, the antimicrobial activity of hop extracts in food appeared to increase with acidity and lower fat content. Our results indicate that hop extracts could be used to control L. monocytogenes in minimally processed food with low fat content. PMID:8930705

  15. A Multicomponent UV Analysis of ["alpha"]- and ["beta"]-Acids in Hops

    ERIC Educational Resources Information Center

    Egts, Haley; Durben, Dan J.; Dixson, John A.; Zehfus, Micheal H.

    2012-01-01

    A method is presented for the determination of ["alpha"]- and ["beta"]-acids (humulones and lupulones) in a hops sample using a multicomponent UV spectroscopic analysis of a methanolic hop extract. When compared with standard methods, this lab can be considered "greener" because it uses smaller volumes of safer solvents (methanol instead of…

  16. The Antimicrobial Effects of Hops (Humulus lupulus L.) on Ruminal Hyper Ammonia-Producing Bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods and Results: Media were prepared with dried hops or hops extract (30.7% lupulone), and inhibited ammonia production by mixed rumen bacteria. The growth and ammonia production of pure cultures (Peptostreptococcus anaerobius, Clostridium aminophilum, or Clostridium sticklandii) was inhibited ...

  17. Protein structure prediction: assembly of secondary structure elements by basin-hopping.

    PubMed

    Hoffmann, Falk; Vancea, Ioan; Kamat, Sanjay G; Strodel, Birgit

    2014-10-20

    The prediction of protein tertiary structure from primary structure remains a challenging task. One possible approach to this problem is the application of basin-hopping global optimization combined with an all-atom force field. In this work, the efficiency of basin-hopping is improved by introducing an approach that derives tertiary structures from the secondary structure assignments of individual residues. This approach is termed secondary-to-tertiary basin-hopping and benchmarked for three miniproteins: trpzip, trp-cage and ER-10. For each of the three miniproteins, the secondary-to-tertiary basin-hopping approach successfully and reliably predicts their three-dimensional structure. When it is applied to larger proteins, correctly folded structures are obtained. It can be concluded that the assembly of secondary structure elements using basin-hopping is a promising tool for de novo protein structure prediction. PMID:25056272

  18. Restoring phase coherence in a one-dimensional superconductor using power-law electron hopping

    NASA Astrophysics Data System (ADS)

    Lobos, Alejandro M.; Tezuka, Masaki; García-García, Antonio M.

    2013-10-01

    In a one-dimensional (1D) superconductor, zero-temperature quantum fluctuations destroy phase coherence. Here we put forward a mechanism which can restore phase coherence: power-law hopping. We study a 1D attractive-U Hubbard model with power-law hopping using Abelian bosonization and density-matrix renormalization group (DMRG) techniques. The parameter that controls the hopping decay acts as the effective, noninteger spatial dimensionality deff. For real-valued hopping amplitudes we identify analytically a range of parameters for which power-law hopping suppresses fluctuations and restores superconducting long-range order for any deff>1, at zero temperature. A detailed DMRG analysis fully supports these findings. These results are also of direct relevance to quantum magnetism as our model can be mapped onto an S=1/2 XXZ spin chain with power-law decaying couplings, which can be studied experimentally with cold-ion-trap techniques.

  19. Leg stiffness of older and younger individuals over a range of hopping frequencies.

    PubMed

    Hobara, Hiroaki; Kobayashi, Yoshiyuki; Yoshida, Eiichi; Mochimaru, Masaaki

    2015-04-01

    The purpose of this study was to compare spring-mass behavior between older and younger individuals at a range of hopping frequencies. A total of 14 elderly and 14 young subjects performed in-place hopping in time with a metronome at frequencies of 2.2, 2.6, and 3.0 Hz. Using a spring-mass model, leg stiffness was calculated as the ratio of maximum ground reaction force to maximum center of mass displacement at the middle of the stance phase during ground contact. The lower extremities of both groups behaved like a simple spring-mass system at all three hopping frequencies. Further, statistical analysis revealed the existence of a significant interaction between hopping frequency and age group on leg stiffness. These results suggest that the sensitivity of leg stiffness to accommodate for variations in hopping frequency is likely to differ between elderly and young individuals. PMID:25716326

  20. Lateral Hopping of CO on Ag(110) by Multiple Overtone Excitation.

    PubMed

    Oh, Junepyo; Lim, Hyunseob; Arafune, Ryuichi; Jung, Jaehoon; Kawai, Maki; Kim, Yousoo

    2016-02-01

    A novel type of action spectrum representing multiple overtone excitations of the v(M-C) mode was observed for lateral hopping of a CO molecule on Ag(110) induced by inelastically tunneled electrons from the tip of a scanning tunneling microscope. The yield of CO hopping shows sharp increases at 261±4  mV, corresponding to the C-O internal stretching mode, and at 61±2, 90±2, and 148±7  mV, even in the absence of corresponding fundamental vibrational modes. The mechanism of lateral CO hopping on Ag(110) was explained by the multistep excitation of overtone modes of v(M-C) based on the numerical fitting of the action spectra, the nonlinear dependence of the hopping rate on the tunneling current, and the hopping barrier obtained from thermal diffusion experiments. PMID:26894720

  1. Structural basis of Vps33A recruitment to the human HOPS complex by Vps16

    PubMed Central

    Graham, Stephen C.; Wartosch, Lena; Gray, Sally R.; Scourfield, Edward J.; Deane, Janet E.; Luzio, J. Paul; Owen, David J.

    2013-01-01

    The multisubunit homotypic fusion and vacuole protein sorting (HOPS) membrane-tethering complex is required for late endosome-lysosome and autophagosome-lysosome fusion in mammals. We have determined the crystal structure of the human HOPS subunit Vps33A, confirming its identity as a Sec1/Munc18 family member. We show that HOPS subunit Vps16 recruits Vps33A to the human HOPS complex and that residues 642–736 are necessary and sufficient for this interaction, and we present the crystal structure of Vps33A in complex with Vps16(642–736). Mutations at the binding interface disrupt the Vps33A–Vps16 interaction both in vitro and in cells, preventing recruitment of Vps33A to the HOPS complex. The Vps33A–Vps16 complex provides a structural framework for studying the association between Sec1/Munc18 proteins and tethering complexes. PMID:23901104

  2. Lateral Hopping of CO on Ag(110) by Multiple Overtone Excitation

    NASA Astrophysics Data System (ADS)

    Oh, Junepyo; Lim, Hyunseob; Arafune, Ryuichi; Jung, Jaehoon; Kawai, Maki; Kim, Yousoo

    2016-02-01

    A novel type of action spectrum representing multiple overtone excitations of the v (M -C ) mode was observed for lateral hopping of a CO molecule on Ag(110) induced by inelastically tunneled electrons from the tip of a scanning tunneling microscope. The yield of CO hopping shows sharp increases at 261 ±4 mV , corresponding to the C-O internal stretching mode, and at 61 ±2 , 90 ±2 , and 148 ±7 mV , even in the absence of corresponding fundamental vibrational modes. The mechanism of lateral CO hopping on Ag(110) was explained by the multistep excitation of overtone modes of v (M -C ) based on the numerical fitting of the action spectra, the nonlinear dependence of the hopping rate on the tunneling current, and the hopping barrier obtained from thermal diffusion experiments.

  3. Structural elucidation of humulone autoxidation products and analysis of their occurrence in stored hops.

    PubMed

    Taniguchi, Yoshimasa; Taniguchi, Harumi; Matsukura, Yasuko; Kawachi, Yasuji; Shindo, Kazutoshi

    2014-06-27

    The transformation of α-acids [in hops (Humulus lupulus L.)] to iso-α-acids (in beer) during the brewing process is well known, but the occurrence and structure of the oxidized α-acids during hop storage are not well documented. Because an understanding of these oxidized compounds is essential to optimize the effects of oxidized hops on the quality of beer, we investigated the autoxidation products of humulone (a representative congener of α-acids) using a simplified autoxidation model. Among the oxidation products, tricyclooxyisohumulones A (1) and B (2), tricycloperoxyisohumulone A (3), deisopropyltricycloisohumulone (4), and the hemiacetal 5 of tricycloperoxyhumulone A (5') were isolated, and their structures were elucidated for the first time. The occurrence of compounds 1-4 in stored hops was verified using LC/MS/MS analysis. We also monitored the levels of compounds 1-4 during hop storage using LC/MS/MS analysis. PMID:24875004

  4. Matured Hop Bittering Components Induce Thermogenesis in Brown Adipose Tissue via Sympathetic Nerve Activity

    PubMed Central

    Morimoto-Kobayashi, Yumie; Ohara, Kazuaki; Takahashi, Chika; Kitao, Sayoko; Wang, Guanying; Taniguchi, Yoshimasa; Katayama, Mikio; Nagai, Katsuya

    2015-01-01

    Obesity is the principal symptom of metabolic syndrome, which refers to a group of risk factors that increase the likelihood of atherosclerosis. In recent decades there has been a sharp rise in the incidence of obesity throughout the developed world. Iso-α-acids, the bitter compounds derived from hops in beer, have been shown to prevent diet-induced obesity by increasing lipid oxidation in the liver and inhibition of lipid absorption from the intestine. Whereas the sharp bitterness induced by effective dose of iso-α-acids precludes their acceptance as a nutrient, matured hop bittering components (MHB) appear to be more agreeable. Therefore, we tested MHB for an effect on ameliorating diet-induced body fat accumulation in rodents. MHB ingestion had a beneficial effect but, compared to iso-α-acids and despite containing structurally similar compounds, acted via different mechanisms to reduce body fat accumulation. MHB supplementation significantly reduced body weight gain, epididymal white adipose tissue weight, and plasma non-esterified free fatty acid levels in diet-induced obese mice. We also found that uncoupling protein 1 (UCP1) expression in brown adipose tissue (BAT) was significantly increased in MHB-fed mice at both the mRNA and protein levels. In addition, MHB administration in rats induced the β-adrenergic signaling cascade, which is related to cAMP accumulation in BAT, suggesting that MHB could modulate sympathetic nerve activity innervating BAT (BAT-SNA). Indeed, single oral administration of MHB elevated BAT-SNA in rats, and this elevation was dissipated by subdiaphragmatic vagotomy. Single oral administration of MHB maintained BAT temperature at a significantly higher level than in control rats. Taken together, these findings indicate that MHB ameliorates diet-induced body fat accumulation, at least partly, by enhancing thermogenesis in BAT via BAT-SNA activation. Our data suggests that MHB is a useful tool for developing functional foods or

  5. Bringing Back Sweet (and Not so Sweet) Memories: The Cultural Politics of Memory, Hip-Hop, and Generational Identities

    ERIC Educational Resources Information Center

    Hill, Marc Lamont

    2009-01-01

    This article examines the salience of collective "memory" and "remembering" among a group of students in Hip-Hop Lit, a hip-hop centered English literature course that I co-taught at "Howard High School," an urban high school in the Northeastern United States. Specifically, this article examines the memory work that occurred within Hip-Hop Lit in…

  6. Relationships between postural orientation and self reported function, hop performance and muscle power in subjects with anterior cruciate ligament injury

    PubMed Central

    2010-01-01

    Background Injury to the anterior cruciate ligament (ACL) is associated not only with knee instability and impaired neuromuscular control, but also with altered postural orientation manifested as observable "substitution patterns". However, tests currently used to evaluate knee function in subjects with ACL injury are not designed to assess postural orientation. Therefore, we are in the process of developing an observational test set that measures postural orientation in terms of the ability to stabilize body segments in relation to each other and to the environment. The aim of the present study was to characterise correlations between this novel test set, called the Test for Substitution Patterns (TSP) and commonly used tests of knee function. Methods In a blinded set-up, 53 subjects (mean age 30 years, range 20-39, with 2-5 years since ACL injury) were assessed using the TSP, the Knee Injury and Osteoarthritis Outcome Score subscale sport/recreation (KOOS sport/rec), 3 hop tests and 3 muscle power tests. Correlations between the scores of the TSP and the other tests were determined. Results Moderate correlations were found between TSP scores and KOOS sport/rec (rs = -0.43; p = 0.001) and between TSP scores and hop test results (rs = -0.40 to -0.46; p ≤ 0.003), indicating that altered postural orientation was associated with worse self-reported KOOS sport/rec function and worse hop performance. No significant correlations were found between TSP scores and muscle power results. Subjects had higher TSP scores on their injured side than on their uninjured side (median 4 and 1 points; interquartile range 2-6 and 0-1.5, respectively; p < 0.0001). Conclusions We conclude that the Test for Substitution Patterns is of relevance to the patient and measures a specific aspect of neuromuscular control not quantified by the other tests investigated. We suggest that the TSP may be a valuable complement in the assessment of neuromuscular control in the rehabilitation of

  7. Partial processing satellite relays for frequency-hop antijam communications

    NASA Astrophysics Data System (ADS)

    Sussman, S. M.; Kotiveeriah, P.

    1982-08-01

    Jamming effects on the uplink and downlink are combined to derive the earth station-to-earth station performance. In the linear dehop-rehop transponder (DRT), the retransmitted uplink noise and jamming for various ratios of relay bandwidth to data rate are taken into account, and a new end-to-end SNR relation is obtained. The symbol regenerative processor (SRP) analysis is based on the appropriate combining of uplink and downlink error probabilities to yield the end-to-end error probability. The jammer is assumed to employ either full-band noise or optimum partial band jamming, and several combinations of these two jamming strategies are evaluated. The relationship between uplink and downlink SNR are obtained for specified end-to-end SNR or error probability, and drawn between the DRT and the SRP. The analysis treats M-ary orthogonal frequency shift typing with incoherent combining and detection of multiple frequency hops per symbol.

  8. Giant magnetoresistance in the variable-range hopping regime

    SciTech Connect

    Ioffe, L. B.; Spivak, B. Z.

    2013-09-15

    We predict the universal power-law dependence of the localization length on the magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative magnetoresistance in the hopping regime. The reason for the universality is that the problem of the electron tunneling in a random media belongs to the same universality class as the directed polymer problem even in the case of wave functions of random sign. We present numerical simulations that prove this conjecture. We discuss the existing experiments that show anomalously large magnetoresistance. We also discuss the role of localized spins in real materials and the spin polarizing effect of the magnetic field.

  9. Improving range resolution with a frequency-hopping technique

    NASA Technical Reports Server (NTRS)

    Stitt, G. R.; Bowhill, S. A.

    1986-01-01

    Range resolution of a conventional pulsed Doppler radar is determined by the scattering volume defined by the transmitted pulse shape. To increase the resolution, the length of the pulse must be reduced. Reducing the pulse length also reduces the transmitted power and hense the signal to noise ratio unless the peak power capability of the transmitter is greatly increased. Improved range resolution may also be attained through the use of various pulse coding methods, but such methods are sometimes difficult to implement from a hardware standpoint. The frequency-hopping (F-H) technique described increases the range resolution of pulse Doppler MST (mesosphere stratosphere troposphere) radar without the need for extensive modifications to the radar transmitter. This technique consists of sending a repeated sequence of pulses, each pulse in the sequence being transmitted at a unique radio frequency that is under the control of a microcomputer. This technique is discussed along with other radar parameters.

  10. Giant magnetoresistance in the variable-range hopping regime

    NASA Astrophysics Data System (ADS)

    Ioffe, L. B.; Spivak, B. Z.

    2013-09-01

    We predict the universal power-law dependence of the localization length on the magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative magnetoresistance in the hopping regime. The reason for the universality is that the problem of the electron tunneling in a random media belongs to the same universality class as the directed polymer problem even in the case of wave functions of random sign. We present numerical simulations that prove this conjecture. We discuss the existing experiments that show anomalously large magnetoresistance. We also discuss the role of localized spins in real materials and the spin polarizing effect of the magnetic field.

  11. Systematic network coding for two-hop lossy transmissions

    NASA Astrophysics Data System (ADS)

    Li, Ye; Blostein, Steven; Chan, Wai-Yip

    2015-12-01

    In this paper, we consider network transmissions over a single or multiple parallel two-hop lossy paths. These scenarios occur in applications such as sensor networks or WiFi offloading. Random linear network coding (RLNC), where previously received packets are re-encoded at intermediate nodes and forwarded, is known to be a capacity-achieving approach for these networks. However, a major drawback of RLNC is its high encoding and decoding complexity. In this work, a systematic network coding method is proposed. We show through both analysis and simulation that the proposed method achieves higher end-to-end rate as well as lower computational cost than RLNC for finite field sizes and finite-sized packet transmissions.

  12. Conductivities and Seebeck coefficients of boron carbides: Softening bipolaron hopping

    NASA Astrophysics Data System (ADS)

    Aselage, T. L.; Emin, D.; McCready, S. S.

    2001-08-01

    The electrical conductivities and Seebeck coefficients of boron carbides B12+xC3-x with 0.06<~x<~1.7 have been measured from 8 K to as high as 1750 K. At high temperature, the temperature dependence of the conductivities is Arrhenius and the activation energy, ~0.16 eV, is independent of the carbon concentration. The preexponential factors of the conductivity exhibit a nonmonotonic dependence on x, peaking near x=1. These results are consistent with a previously proposed model based on holes forming singlet bipolarons on the boron carbide B11C icosahedra. At low temperature, the boron carbide conductivities are non-Arrhenius with a temperature dependence that is a strong function of the composition x. This strong sensitivity to composition indicates that percolation effects, arising from boron carbides having carbon atoms in inequivalent locations, influence the conductivity at low temperature. With x holes per unit cell, boron carbides have very large Seebeck coefficients that depend only weakly on x. The magnitudes and temperature dependences of the Seebeck coefficients are consistent with large contributions from carrier-induced softening of local vibrations. Softening effects can be exceptionally large when singlet bipolarons are stabilized among degenerate electronic energy levels by their softening of symmetry-breaking vibrations: ``softening bipolarons.'' The boron carbide transport properties are generally consistent with those expected of softening bipolarons. Finally, two high-temperature effects are observed in the boron carbide conductivities. The conductivities of samples having high carrier densities, x~1, are suppressed above 700 K. This suppression can arise when the rapid hopping of nearby carriers disrupts the energy coincidence required for a carrier's hop. At even higher temperatures, a sharp increase in the boron carbide conductivities (σ~T4) suggests a radiation-induced excitation of mobile charge carriers.

  13. Understanding hopping transport and thermoelectric properties of conducting polymers

    NASA Astrophysics Data System (ADS)

    Ihnatsenka, S.; Crispin, X.; Zozoulenko, I. V.

    2015-07-01

    We calculate the conductivity σ and the Seebeck coefficient S for the phonon-assisted hopping transport in conducting polymers poly(3,4-ethylenedioxythiophene) or PEDOT, experimentally studied by Bubnova et al. [J. Am. Chem. Soc. 134, 16456 (2012)], 10.1021/ja305188r. We use the Monte Carlo technique as well as the semianalytical approach based on the transport energy concept. We demonstrate that both approaches show a good qualitative agreement for the concentration dependence of σ and S . At the same time, we find that the semianalytical approach is not in a position to describe the temperature dependence of the conductivity. We find that both Gaussian and exponential density of states (DOS) reproduce rather well the experimental data for the concentration dependence of σ and S giving similar fitting parameters of the theory. The obtained parameters correspond to a hopping model of localized quasiparticles extending over 2-3 monomer units with typical jumps over a distance of 3-4 units. The energetic disorder (broadening of the DOS) is estimated to be 0.1 eV. Using the Monte Carlo calculation we reproduce the activation behavior of the conductivity with the calculated activation energy close to the experimentally observed one. We find that for a low carrier concentration a number of free carriers contributing to the transport deviates strongly from the measured oxidation level. Possible reasons for this behavior are discussed. We also study the effect of the dimensionality on the charge transport by calculating the Seebeck coefficient and the conductivity for the cases of three-, two-, and one-dimensional motion.

  14. Coding for frequency hopped spread spectrum satellite communications

    NASA Astrophysics Data System (ADS)

    Bhargava, Vijay K.; Wang, Qiang; Blake, Ian F.; Li, Gang; Gulliver, T. Aaron; Dravnieks, Olaf

    1990-04-01

    Work aimed at improving the jamming resistance of satellite communications is reviewed. The performance of Reed-Solomon (RS) error correcting codes with slow frequency hopped (SFH) differential phase shift keying (DPSK) signalling is analyzed and evaluated under worst case partial band noise and worst case multitone jamming. A representative set of performance curves is shown. Recommendation on the choice of RS code parameters is given. Two in-hop jamming cancellation schemes for SFH/DPSK systems are proposed. One scheme is based on balanced coding; the other one uses notch filter to cancel jamming tone. The performance of both schemes is illustrated. It is shown that both schemes can work well under certain conditions. Basic principles and techniques for designing interleavers are presented. Block, convolution, and the more recent helical interleavers are considered. The trade-off between diversity and coding for spread spectrum systems, where a low code rate is anticipated, is discussed. An error correction scheme is presented for an M-ary symmetric channel (MSC) characterized by a large error probability (Pe). The value of Pe can be near, but smaller than 1-1/M, for which the channel capacity is zero. Such a large Pe may occur, for example, in a jamming environment. Monte-Carlo simulation results are presented. For the binary symmetric channel (BSC), it is shown that the overall code rate is larger than 0.6 R sub 0, where R sub 0 is the cutoff rate of the channel. For BSC and a large diversity order (m), a method is presented for BER (bit error rate) approximation on the central limit theorem.

  15. Coupled catastrophes: sudden shifts cascade and hop among interdependent systems.

    PubMed

    Brummitt, Charles D; Barnett, George; D'Souza, Raissa M

    2015-11-01

    An important challenge in several disciplines is to understand how sudden changes can propagate among coupled systems. Examples include the synchronization of business cycles, population collapse in patchy ecosystems, markets shifting to a new technology platform, collapses in prices and in confidence in financial markets, and protests erupting in multiple countries. A number of mathematical models of these phenomena have multiple equilibria separated by saddle-node bifurcations. We study this behaviour in its normal form as fast-slow ordinary differential equations. In our model, a system consists of multiple subsystems, such as countries in the global economy or patches of an ecosystem. Each subsystem is described by a scalar quantity, such as economic output or population, that undergoes sudden changes via saddle-node bifurcations. The subsystems are coupled via their scalar quantity (e.g. trade couples economic output; diffusion couples populations); that coupling moves the locations of their bifurcations. The model demonstrates two ways in which sudden changes can propagate: they can cascade (one causing the next), or they can hop over subsystems. The latter is absent from classic models of cascades. For an application, we study the Arab Spring protests. After connecting the model to sociological theories that have bistability, we use socioeconomic data to estimate relative proximities to tipping points and Facebook data to estimate couplings among countries. We find that although protests tend to spread locally, they also seem to 'hop' over countries, like in the stylized model; this result highlights a new class of temporal motifs in longitudinal network datasets. PMID:26559684

  16. Coupled catastrophes: sudden shifts cascade and hop among interdependent systems

    PubMed Central

    Barnett, George; D'Souza, Raissa M.

    2015-01-01

    An important challenge in several disciplines is to understand how sudden changes can propagate among coupled systems. Examples include the synchronization of business cycles, population collapse in patchy ecosystems, markets shifting to a new technology platform, collapses in prices and in confidence in financial markets, and protests erupting in multiple countries. A number of mathematical models of these phenomena have multiple equilibria separated by saddle-node bifurcations. We study this behaviour in its normal form as fast–slow ordinary differential equations. In our model, a system consists of multiple subsystems, such as countries in the global economy or patches of an ecosystem. Each subsystem is described by a scalar quantity, such as economic output or population, that undergoes sudden changes via saddle-node bifurcations. The subsystems are coupled via their scalar quantity (e.g. trade couples economic output; diffusion couples populations); that coupling moves the locations of their bifurcations. The model demonstrates two ways in which sudden changes can propagate: they can cascade (one causing the next), or they can hop over subsystems. The latter is absent from classic models of cascades. For an application, we study the Arab Spring protests. After connecting the model to sociological theories that have bistability, we use socioeconomic data to estimate relative proximities to tipping points and Facebook data to estimate couplings among countries. We find that although protests tend to spread locally, they also seem to ‘hop' over countries, like in the stylized model; this result highlights a new class of temporal motifs in longitudinal network datasets. PMID:26559684

  17. Hopping of an impurity defect in ion crystals in linear traps

    NASA Astrophysics Data System (ADS)

    Liang, J.; Haljan, P. C.

    2011-06-01

    Laser-cooled arrays or crystals of Yb171+ ions containing a single impurity, Yb172+ isotope, are confined in a linear radio-frequency Paul trap. Site-to-site hopping of the impurity ion, distinguished by a lack of fluorescence, is studied as a function of the Yb171+ laser-cooling parameters and as a function of the anisotropy of the trapping potential. Imaging of the independently resolved crystal sites permits the extraction of the impurity’s hopping trajectory, from which the dwell times at a given site can be obtained as well as the spatial distribution of hopping rate and hopping destination. The onset of rapid hopping is found to occur at average thermal energies approaching a significant fraction of the Coulomb potential energy. Furthermore, the hopping rate is enhanced at trap anisotropies near the critical value for the structural phase transition to a two-dimensional zigzag phase. Finally, the hopping mobility of the impurity ion is observed to be highest near the center of the crystal, which may have an intrinsic cause related to the crystal structure and dynamics near the zigzag transition.

  18. RILP interacts with HOPS complex via VPS41 subunit to regulate endocytic trafficking

    PubMed Central

    Lin, Xiaosi; Yang, Ting; Wang, Shicong; Wang, Zhen; Yun, Ye; Sun, Lixiang; Zhou, Yunhe; Xu, Xiaohui; Akazawa, Chihiro; Hong, Wanjin; Wang, Tuanlao

    2014-01-01

    The HOPS complex serves as a tethering complex with GEF activity for Ypt7p in yeast to regulate late endosomal membrane maturation. While the role of HOPS complex is well established in yeast cells, its functional and mechanistic aspects in mammalian cells are less well defined. In this study, we report that RILP, a downstream effector of Rab7, interacts with HOPS complex and recruits HOPS subunits to the late endosomal compartment. Structurally, the amino-terminal portion of RILP interacts with HOPS complex. Unexpectedly, this interaction is independent of Rab7. VPS41 subunit of HOPS complex was defined to be the major partner for interacting with RILP. The carboxyl-terminal region of VPS41 was mapped to be responsible for the interaction. Functionally, either depletion of VPS41 by shRNA or overexpression of VPS41 C-terminal half retarded EGF-induced degradation of EGFR. These results suggest that interaction of RILP with HOPS complex via VPS41 plays a role in endocytic trafficking of EGFR. PMID:25445562

  19. Cytotoxic effect of commercial Humulus lupulus L. (hop) preparations - In comparison to its metabolomic fingerprint.

    PubMed

    Farag, Mohamed A; Wessjohann, Ludger A

    2013-07-01

    Hops (Humulus lupulus L. Cannabaceae) is an economically important crop, that has drawn more attention in recent years due to its potential pharmaceutical applications. Bitter acids (prenylated polyketides) and prenylflavonoids are the primary phytochemical components that account for hops resins medicinal value. We have previously reported on utilizing untargeted NMR and MS metabolomics for analysis of 13 hops cultivars, revealing for differences in α- versus β-bitter acids composition in derived resins. In this study, effect of ratios of bitter α- to β-acids in hop resins to cytotoxicity of hop resins was investigated. In vitro cell culture assays revealed that β-acids were more effective than α-acids in growth inhibition of PC3 and HT29 cancer cell lines. Nevertheless, hop resins enriched in β-acids showed comparable growth inhibition patterns to α-enriched resins and suggesting that bioactivity may not be easily predicted by metabolomics and/or gross metabolic profiling in hops. PMID:25685448

  20. Terpene Biosynthesis in Glandular Trichomes of Hop12[W][OA

    PubMed Central

    Wang, Guodong; Tian, Li; Aziz, Naveed; Broun, Pierre; Dai, Xinbin; He, Ji; King, Andrew; Zhao, Patrick X.; Dixon, Richard A.

    2008-01-01

    Hop (Humulus lupulus L. Cannabaceae) is an economically important crop for the brewing industry, where it is used to impart flavor and aroma to beer, and has also drawn attention in recent years due to its potential pharmaceutical applications. Essential oils (mono- and sesquiterpenes), bitter acids (prenylated polyketides), and prenylflavonoids are the primary phytochemical components that account for these traits, and all accumulate at high concentrations in glandular trichomes of hop cones. To understand the molecular basis for terpene accumulation in hop trichomes, a trichome cDNA library was constructed and 9,816 cleansed expressed sequence tag (EST) sequences were obtained from random sequencing of 16,152 cDNA clones. The ESTs were assembled into 3,619 unigenes (1,101 contigs and 2,518 singletons). Putative functions were assigned to the unigenes based on their homology to annotated sequences in the GenBank database. Two mono- and two sesquiterpene synthases identified from the EST collection were expressed in Escherichia coli. Hop MONOTERPENE SYNTHASE2 formed the linear monterpene myrcene from geranyl pyrophosphate, whereas hop SESQUITERPENE SYNTHASE1 (HlSTS1) formed both caryophyllene and humulene from farnesyl pyrophosphate. Together, these enzymes account for the production of the major terpene constituents of the hop trichomes. HlSTS2 formed the minor sesquiterpene constituent germacrene A, which was converted to β-elemene on chromatography at elevated temperature. We discuss potential functions for other genes expressed at high levels in developing hop trichomes. PMID:18775972

  1. Cytotoxic effect of commercial Humulus lupulus L. (hop) preparations – In comparison to its metabolomic fingerprint

    PubMed Central

    Farag, Mohamed A.; Wessjohann, Ludger A.

    2012-01-01

    Hops (Humulus lupulus L. Cannabaceae) is an economically important crop, that has drawn more attention in recent years due to its potential pharmaceutical applications. Bitter acids (prenylated polyketides) and prenylflavonoids are the primary phytochemical components that account for hops resins medicinal value. We have previously reported on utilizing untargeted NMR and MS metabolomics for analysis of 13 hops cultivars, revealing for differences in α- versus β-bitter acids composition in derived resins. In this study, effect of ratios of bitter α- to β-acids in hop resins to cytotoxicity of hop resins was investigated. In vitro cell culture assays revealed that β-acids were more effective than α-acids in growth inhibition of PC3 and HT29 cancer cell lines. Nevertheless, hop resins enriched in β-acids showed comparable growth inhibition patterns to α-enriched resins and suggesting that bioactivity may not be easily predicted by metabolomics and/or gross metabolic profiling in hops. PMID:25685448

  2. Vibrational spectroscopy and chemometrics for rapid, quantitative analysis of bitter acids in hops (Humulus lupulus).

    PubMed

    Killeen, Daniel P; Andersen, David H; Beatson, Ron A; Gordon, Keith C; Perry, Nigel B

    2014-12-31

    Hops, Humulus lupulus, are grown worldwide for use in the brewing industry to impart characteristic flavor and aroma to finished beer. Breeders produce many varietal crosses with the aim of improving and diversifying commercial hops varieties. The large number of crosses critical to a successful breeding program imposes high demands on the supporting chemical analytical laboratories. With the aim of reducing the analysis time associated with hops breeding, quantitative partial least-squares regression (PLS-R) models have been produced, relating reference data acquired by the industrial standard HPLC and UV methods, to vibrational spectra of the same, chemically diverse hops sample set. These models, produced from rapidly acquired infrared (IR), near-infrared (NIR), and Raman spectra, were appraised using standard statistical metrics. Results demonstrated that all three spectroscopic methods could be used for screening hops for α-acid, total bitter acids, and cohumulone concentrations in powdered hops. Models generated from Raman and IR spectra also showed potential for use in screening hops varieties for xanthohumol concentrations. NIR analysis was performed using both a standard benchtop spectrometer and a portable NIR spectrometer, with comparable results obtained by both instruments. Finally, some important vibrational features of cohumulone, colupulone, and xanthohumol were assigned using DFT calculations, which allow more insightful interpretation of PLS-R latent variable plots. PMID:25485767

  3. Hop, an active Mutator-like element in the genome of the fungus Fusarium oxysporum.

    PubMed

    Chalvet, Fabienne; Grimaldi, Christine; Kaper, Fiona; Langin, Thierry; Daboussi, Marie-Josée

    2003-08-01

    A new type of active DNA transposon has been identified in the genome of Fusarium oxysporum by its transposition into the niaD target gene. Two insertions within the final exon, in opposite orientations at the same nucleotide site, have been characterized. These elements, called Hop, are 3,299 bp long, with perfect terminal inverted repeats (TIRs) of 99 bp. The sequencing of genomic copies reveals a 9-bp target site duplication and no apparent sequence specificity at the insertion sites. The sequencing of a cDNA indicates that Hop does not contain an intron and encodes a putative transposase of 836 amino acids. The structural features (length, TIRs size, and 9-bp duplication), together with the presence of conserved domains in the transposase, strongly suggest that Hop is a Mutator-like element (MULE). Hop is thus the first active member of this family found beyond plants. The high rate of excision observed indicates that Hop is very active and thus represents a promising efficient tagging system for the isolation of fungal genes. The distribution of Hop elements within the Fusarium genus revealed that they are present in different species, suggesting that related elements could be present in other fungal genomes. In fact, Hop-related sequences have been identified in the survey of the entire genome sequence of three other ascomycetes, Magnaporthe grisea, Neurospora crassa, and Aspergillus fumigatus. PMID:12777515

  4. Pseudomonas syringae Effector HopF2 Suppresses Arabidopsis Immunity by Targeting BAK1

    PubMed Central

    Zhou, Jinggeng; Wu, Shujing; Chen, Xin; Liu, Chenglong; Sheen, Jen; Shan, Libo; He, Ping

    2014-01-01

    Summary Pseudomonas syringae delivers a plethora of effector proteins into host cells to sabotage immune responses and modulate physiology to favor infection. We have previously shown that P. syringae pv. tomato DC3000 effector HopF2 suppresses Arabidopsis innate immunity triggered by multiple microbe-associated molecular patterns (MAMP) at the plasma membrane. We show here that HopF2 possesses distinct mechanisms in the suppression of two branches of MAMP-activated MAP kinase (MPK) cascades. Besides blocking MKK5 (MPK kinase 5) activation in the MEKK1/MEKKs-MKK4/5-MPK3/6 cascade, HopF2 targets additional component(s) upstream of MEKK1 in the MEKK1-MKK1/2-MPK4 cascade and plasma membrane-localized receptor-like cytoplasmic kinase BIK1 and its homologs. We further show that HopF2 directly targets BAK1, a plasma membrane-localized receptor-like kinase involved in multiple MAMP signaling. The interaction between BAK1 and HopF2 or two other P. syringae effectors AvrPto and AvrPtoB, was confirmed in vivo and in vitro. Consistent with BAK1 as a physiological target of AvrPto, AvrPtoB and HopF2, the strong growth defects or lethality associated with ectopic expression of these effectors in wild-type Arabidopsis transgenic plants were largely alleviated in bak1 mutant plants. Thus, our results provide genetic evidence to further support that BAK1 is a physiological target of AvrPto, AvrPtoB and HopF2. Identification of BAK1 as an additional target of HopF2 virulence not only explains HopF2 suppression of multiple MAMP signaling at the plasma membrane, but also supports the notion that pathogen virulence effectors act through multiple targets in host cells. PMID:24237140

  5. Animal galloping and human hopping: an energetics and biomechanics laboratory exercise

    PubMed Central

    Lindstedt, Stan L.; Mineo, Patrick M.

    2013-01-01

    This laboratory exercise demonstrates fundamental principles of mammalian locomotion. It provides opportunities to interrogate aspects of locomotion from biomechanics to energetics to body size scaling. It has the added benefit of having results with robust signal to noise so that students will have success even if not “meticulous” in attention to detail. First, using respirometry, students measure the energetic cost of hopping at a “preferred” hop frequency. This is followed by hopping at an imposed frequency half of the preferred. By measuring the O2 uptake and work done with each hop, students calculate mechanical efficiency. Lessons learned from this laboratory include 1) that the metabolic cost per hop at half of the preferred frequency is nearly double the cost at the preferred frequency; 2) that when a person is forced to hop at half of their preferred frequency, the mechanical efficiency is nearly that predicted for muscle but is much higher at the preferred frequency; 3) that the preferred hop frequency is strongly body size dependent; and 4) that the hop frequency of a human is nearly identical to the galloping frequency predicted for a quadruped of our size. Together, these exercises demonstrate that humans store and recover elastic recoil potential energy when hopping but that energetic savings are highly frequency dependent. This stride frequency is dependent on body size such that frequency is likely chosen to maximize this function. Finally, by requiring students to make quantitative solutions using appropriate units and dimensions of the physical variables, these exercises sharpen analytic and quantitative skills. PMID:24292916

  6. The Pseudomonas syringae effector HopF2 suppresses Arabidopsis immunity by targeting BAK1.

    PubMed

    Zhou, Jinggeng; Wu, Shujing; Chen, Xin; Liu, Chenglong; Sheen, Jen; Shan, Libo; He, Ping

    2014-01-01

    Pseudomonas syringae delivers a plethora of effector proteins into host cells to sabotage immune responses and modulate physiology to favor infection. The P. syringae pv. tomato DC3000 effector HopF2 suppresses Arabidopsis innate immunity triggered by multiple microbe-associated molecular patterns (MAMP) at the plasma membrane. We show here that HopF2 possesses distinct mechanisms for suppression of two branches of MAMP-activated MAP kinase (MAPK) cascades. In addition to blocking MKK5 (MAPK kinase 5) activation in the MEKK1 (MAPK kinase kinase 1)/MEKKs-MKK4/5-MPK3/6 cascade, HopF2 targets additional component(s) upstream of MEKK1 in the MEKK1-MKK1/2-MPK4 cascade and the plasma membrane-localized receptor-like cytoplasmic kinase BIK1 and its homologs. We further show that HopF2 directly targets BAK1, a plasma membrane-localized receptor-like kinase that is involved in multiple MAMP signaling. The interaction between BAK1 and HopF2 and between two other P. syringae effectors, AvrPto and AvrPtoB, was confirmed in vivo and in vitro. Consistent with BAK1 as a physiological target of AvrPto, AvrPtoB and HopF2, the strong growth defects or lethality associated with ectopic expression of these effectors in wild-type Arabidopsis transgenic plants were largely alleviated in bak1 mutant plants. Thus, our results provide genetic evidence to show that BAK1 is a physiological target of AvrPto, AvrPtoB and HopF2. Identification of BAK1 as an additional target of HopF2 virulence not only explains HopF2 suppression of multiple MAMP signaling at the plasma membrane, but also supports the notion that pathogen virulence effectors act through multiple targets in host cells. PMID:24237140

  7. Falicov-Kimball model extended by pair hopping of d-electrons

    NASA Astrophysics Data System (ADS)

    Ghosh, N. K.; Mukherjee, P.

    2016-05-01

    The effect of the pair hopping of d-electrons has been examined in an exact diagonalization techniqueon a four-site square cluster using extended Falicov-Kimball model. This hopping interaction shifts the critical f-level energy (Ec) at which valence transition occurs. Sharp peaks are observed in the specific heat curves and pair hopping decreases the peak height indicating a reduction in the number of density of states. Antiferromagnetic ordering as well as Curie-like behavior has been observed in the spin susceptibility (χ) characteristics.

  8. High temperature electrical conductivity due to small polaron hopping motion in DNA molecules

    NASA Astrophysics Data System (ADS)

    Triberis, G. P.; Karavolas, V. C.; Simserides, C. D.

    2005-01-01

    We present a small polaron hopping model to interpret the high-temperature electrical conductivity measured along the DNA molecules. The model takes into account the one-dimensional character of the system and the presence of disorder in the DNA double helix. The experimental data for the lambda phage DNA (λ-DNA) and the poly(dA)-poly(dT) DNA follow nicely the theoretically predicted behavior leading to realistic values of the maximum hopping distances supporting the idea of multiphonon-assisted hopping of small polarons between next nearest neighbors of the DNA molecular "wire".

  9. Plasmodium falciparum Hop (PfHop) Interacts with the Hsp70 Chaperone in a Nucleotide-Dependent Fashion and Exhibits Ligand Selectivity.

    PubMed

    Zininga, Tawanda; Makumire, Stanely; Gitau, Grace Wairimu; Njunge, James M; Pooe, Ofentse Jacob; Klimek, Hanna; Scheurr, Robina; Raifer, Hartmann; Prinsloo, Earl; Przyborski, Jude M; Hoppe, Heinrich; Shonhai, Addmore

    2015-01-01

    Heat shock proteins (Hsps) play an important role in the development and pathogenicity of malaria parasites. One of the most prominent functions of Hsps is to facilitate the folding of other proteins. Hsps are thought to play a crucial role when malaria parasites invade their host cells and during their subsequent development in hepatocytes and red blood cells. It is thought that Hsps maintain proteostasis under the unfavourable conditions that malaria parasites encounter in the host environment. Although heat shock protein 70 (Hsp70) is capable of independent folding of some proteins, its functional cooperation with heat shock protein 90 (Hsp90) facilitates folding of some proteins such as kinases and steroid hormone receptors into their fully functional forms. The cooperation of Hsp70 and Hsp90 occurs through an adaptor protein called Hsp70-Hsp90 organising protein (Hop). We previously characterised the Hop protein from Plasmodium falciparum (PfHop). We observed that the protein co-localised with the cytosol-localised chaperones, PfHsp70-1 and PfHsp90 at the blood stages of the malaria parasite. In the current study, we demonstrated that PfHop is a stress-inducible protein. We further explored the direct interaction between PfHop and PfHsp70-1 using far Western and surface plasmon resonance (SPR) analyses. The interaction of the two proteins was further validated by co-immunoprecipitation studies. We observed that PfHop and PfHsp70-1 associate in the absence and presence of either ATP or ADP. However, ADP appears to promote the association of the two proteins better than ATP. In addition, we investigated the specific interaction between PfHop TPR subdomains and PfHsp70-1/ PfHsp90, using a split-GFP approach. This method allowed us to observe that TPR1 and TPR2B subdomains of PfHop bind preferentially to the C-terminus of PfHsp70-1 compared to PfHsp90. Conversely, the TPR2A motif preferentially interacted with the C-terminus of PfHsp90. Finally, we observed that

  10. Plasmodium falciparum Hop (PfHop) Interacts with the Hsp70 Chaperone in a Nucleotide-Dependent Fashion and Exhibits Ligand Selectivity

    PubMed Central

    Zininga, Tawanda; Makumire, Stanely; Gitau, Grace Wairimu; Njunge, James M.; Pooe, Ofentse Jacob; Klimek, Hanna; Scheurr, Robina; Raifer, Hartmann; Prinsloo, Earl; Przyborski, Jude M.; Hoppe, Heinrich; Shonhai, Addmore

    2015-01-01

    Heat shock proteins (Hsps) play an important role in the development and pathogenicity of malaria parasites. One of the most prominent functions of Hsps is to facilitate the folding of other proteins. Hsps are thought to play a crucial role when malaria parasites invade their host cells and during their subsequent development in hepatocytes and red blood cells. It is thought that Hsps maintain proteostasis under the unfavourable conditions that malaria parasites encounter in the host environment. Although heat shock protein 70 (Hsp70) is capable of independent folding of some proteins, its functional cooperation with heat shock protein 90 (Hsp90) facilitates folding of some proteins such as kinases and steroid hormone receptors into their fully functional forms. The cooperation of Hsp70 and Hsp90 occurs through an adaptor protein called Hsp70-Hsp90 organising protein (Hop). We previously characterised the Hop protein from Plasmodium falciparum (PfHop). We observed that the protein co-localised with the cytosol-localised chaperones, PfHsp70-1 and PfHsp90 at the blood stages of the malaria parasite. In the current study, we demonstrated that PfHop is a stress-inducible protein. We further explored the direct interaction between PfHop and PfHsp70-1 using far Western and surface plasmon resonance (SPR) analyses. The interaction of the two proteins was further validated by co-immunoprecipitation studies. We observed that PfHop and PfHsp70-1 associate in the absence and presence of either ATP or ADP. However, ADP appears to promote the association of the two proteins better than ATP. In addition, we investigated the specific interaction between PfHop TPR subdomains and PfHsp70-1/ PfHsp90, using a split-GFP approach. This method allowed us to observe that TPR1 and TPR2B subdomains of PfHop bind preferentially to the C-terminus of PfHsp70-1 compared to PfHsp90. Conversely, the TPR2A motif preferentially interacted with the C-terminus of PfHsp90. Finally, we observed that

  11. Spin transport in disordered two-dimensional hopping systems with Rashba spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Beckmann, U.; Damker, T.; Böttger, H.

    2005-05-01

    The influence of Rashba spin-orbit interaction on the spin dynamics of a topologically disordered hopping system is studied in this paper. This is a significant generalization of a previous investigation, where an ordered (polaronic) hopping system has been considered instead. It is found that in the limit where the Rashba length is large compared to the typical hopping length, the spin dynamics of a disordered system can still be described by the expressions derived for an ordered system, under the provision that one takes into account the frequency dependence of the diffusion constant and the mobility (which are determined by charge transport and are independent of spin). With these results we are able to make explicit the influence of disorder on spin related quantities as, e.g., the spin lifetime in hopping systems.

  12. Negative magnetoresistance in the variable-range-hopping regime in n-type CdSe

    NASA Astrophysics Data System (ADS)

    Zhang, Youzhu; Sarachik, M. P.

    1991-03-01

    The magnetoresistance in the variable-range-hopping regime of compensated, n-type CdSe measured between 1.6 and 6 K in the Ohmic regime at small magnetic fields is negative and obeys the expression ΔR/R=f(T)B2, with f(T)~T-α and α=1.32+/-0.04. As in recent experiments by Tremblay et al. on GaAs, this temperature dependence is observed for all samples independently of whether the resistivity at zero field indicates Mott hopping or variable-range hopping in the presence of a Coulomb gap. This implies either that the relevant dephasing time is not the hopping time, or that our current understanding of the negative magnetoresistance in these materials is incomplete.

  13. Cryopreservation and maintenance of hop material in the USDA germplasm collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The US Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository (NCGR) has the responsibility for conservation of the hop (Humulus L.) genetic resources. The collection includes about 530 accessions representing 7 taxa (species and subspecies) from 21 countries....

  14. Memory effects, two color percolation, and the temperature dependence of Mott variable-range hopping

    NASA Astrophysics Data System (ADS)

    Agam, Oded; Aleiner, Igor L.

    2014-06-01

    There are three basic processes that determine hopping transport: (a) hopping between normally empty sites (i.e., having exponentially small occupation numbers at equilibrium), (b) hopping between normally occupied sites, and (c) transitions between normally occupied and unoccupied sites. In conventional theories all these processes are considered Markovian and the correlations of occupation numbers of different sites are believed to be small (i.e., not exponential in temperature). We show that, contrary to this belief, memory effects suppress the processes of type (c) and manifest themselves in a subleading exponential temperature dependence of the variable-range hopping conductivity. This temperature dependence originates from the property that sites of type (a) and (b) form two independent resistor networks that are weakly coupled to each other by processes of type (c). This leads to a two-color percolation problem which we solve in the critical region.

  15. Lower eccentric hamstring strength and single leg hop for distance predict hamstring injury in PETE students.

    PubMed

    Goossens, L; Witvrouw, E; Vanden Bossche, L; De Clercq, D

    2015-01-01

    Hamstring injuries have not been under research in physical education teacher education (PETE) students so far. Within the frame of the development of an injury prevention program, for this study we conducted an analysis of modifiable risk factors for hamstring injuries in PETE students. Hamstring injuries of 102 freshmen bachelor PETE students were registered prospectively during one academic year. Eighty-one students completed maximum muscle strength tests of hip extensors, hamstrings, quadriceps (isometric) and hamstrings (eccentric) at the start of the academic year. Sixty-nine of the latter completed a single leg hop for distance (SLHD). Risk factors for hamstring injuries were statistically detected using logistic regression. Sixteen hamstring injuries (0.16 injuries/student/academic year; 0.46 injuries/1000 h) occurred to 10 participants. Eight cases were included in the risk factor analysis. Lower eccentric hamstring strength (odds ratio (ODD) = 0.977; p = 0.043), higher isometric/eccentric hamstring strength ratio (ODD = 970.500; p = 0.019) and lower score on the SLHD (ODD = 0.884; p = 0.005) were significant risk factors for hamstring injury. A combination of eccentric hamstring strength test and SLHD could give a good risk analysis of hamstring injuries in PETE students. This might offer great perspectives for easily applicable screening in a clinical setting. PMID:25189278

  16. Oestrogenicity of prenylflavonoids from hops: activation of pro-oestrogens by intestinal bacteria.

    PubMed

    Possemiers, Sam; Verstraete, Willy

    2009-04-01

    For many centuries, hops (Humulus lupulus L.) have been used as essential ingredient in beers, providing the typical bitterness and hoppy flavour. However, the last few years the plant has gained increasing attention as a source of prenylflavonoids and in 1999, 8-prenylnaringenin (8-PN) was identified as the most potent phyto-oestrogen known so far. Hop extracts are therefore now marketed to reduce menopausal complaints. However, 8-PN concentrations in hops are very low, and variable efficiency of these extracts was observed. Yet, hops also contain isoxanthohumol (IX) in much higher amounts (IX/8-PN ratio in hop extracts is typically 10-20). This article reviews our recent findings on how the human intestinal microbiota may activate IX. Depending on inter-individual differences in the intestinal transformation potential, this conversion could easily increase the 8-PN exposure 10-fold. The variability in efficacy of hop extracts may therefore be explained by variable intestinal metabolism. Based on this scientific knowledge, an innovative strategy was developed to decrease this variability. First, Eubacterium limosum, capable of rapidly metabolizing all IX into 8-PN, was isolated from the complex intestinal ecosystem. This bacterium was then used to develop a new generation of hop products with increased reliability in effect. This strategy involves the use of the bacterium as probiotic, in which the bacterium is administered in combination with the original hop extract. This leads to efficient intestinal 8-PN production, also in individuals who originally did not harbour the appropriate bacteria. The findings presented in this review can therefore be considered as a typical example that good insight in the specific metabolic potential of complex microbial communities and individual bacterial species may offer important opportunities for the management and modulation of the microbial organization towards a certain metabolic function. PMID:23765740

  17. Multifrequency channel microwave reflectometer with frequency hopping operation for density fluctuation measurements in Large Helical Device

    SciTech Connect

    Tokuzawa, T.; Kawahata, K.; Ejiri, A.

    2010-10-15

    In order to measure the internal structure of density fluctuations using a microwave reflectometer, the broadband frequency tunable system, which has the ability of fast and stable hopping operation, has been improved in the Large Helical Device. Simultaneous multipoint measurement is the key issue of this development. For accurate phase measurement, the system utilizes a single sideband modulation technique. Currently, a dual channel heterodyne frequency hopping reflectometer system has been constructed and applied to the Alfven eigenmode measurements.

  18. Characterisation of the Plasmodium falciparum Hsp70-Hsp90 organising protein (PfHop).

    PubMed

    Gitau, Grace W; Mandal, Pradipta; Blatch, Gregory L; Przyborski, Jude; Shonhai, Addmore

    2012-03-01

    Malaria is caused by Plasmodium species, whose transmission to vertebrate hosts is facilitated by mosquito vectors. The transition from the cold blooded mosquito vector to the host represents physiological stress to the parasite, and additionally malaria blood stage infection is characterised by intense fever periods. In recent years, it has become clear that heat shock proteins play an essential role during the parasite's life cycle. Plasmodium falciparum expresses two prominent heat shock proteins: heat shock protein 70 (PfHsp70) and heat shock protein 90 (PfHsp90). Both of these proteins have been implicated in the development and pathogenesis of malaria. In eukaryotes, Hsp70 and Hsp90 proteins are functionally linked by an essential adaptor protein known as the Hsp70-Hsp90 organising protein (Hop). In this study, recombinant P. falciparum Hop (PfHop) was heterologously produced in E. coli and purified by nickel affinity chromatography. Using specific anti-PfHop antisera, the expression and localisation of PfHop in P. falciparum was investigated. PfHop was shown to co-localise with PfHsp70 and PfHsp90 in parasites at the trophozoite stage. Gel filtration and co-immunoprecipitation experiments suggested that PfHop was present in a complex together with PfHsp70 and PfHsp90. The association of PfHop with both PfHsp70 and PfHsp90 suggests that this protein may mediate the functional interaction between the two chaperones. PMID:22005844

  19. Quantitative genetic parameters for yield, plant growth and cone chemical traits in hop (Humulus lupulus L.)

    PubMed Central

    2014-01-01

    Background Most traits targeted in the genetic improvement of hop are quantitative in nature. Improvement based on selection of these traits requires a comprehensive understanding of their inheritance. This study estimated quantitative genetic parameters for 20 traits related to three key objectives for the genetic improvement of hop: cone chemistry, cone yield and agronomic characteristics. Results Significant heritable genetic variation was identified for α-acid and β-acid, as well as their components and relative proportions. Estimates of narrow-sense heritability for these traits (h 2  = 0.15 to 0.29) were lower than those reported in previous hop studies, but were based on a broader suite of families (108 from European, North American and hybrid origins). Narrow-sense heritabilities are reported for hop growth traits for the first time (h 2  = 0.04 to 0.20), relating to important agronomic characteristics such as emergence, height and lateral morphology. Cone chemistry and growth traits were significantly genetically correlated, such that families with more vigorous vegetative growth were associated with lower α-acid and β-acid levels. This trend may reflect the underlying population structure of founder genotypes (European and North American origins) as well as past selection in the Australian environment. Although male and female hop plants are thought to be indistinguishable until flowering, sex was found to influence variation in many growth traits, with male and female plants displaying differences in vegetative morphology from emergence to cone maturity. Conclusions This study reveals important insights into the genetic control of quantitative hop traits. The information gained will provide hop breeders with a greater understanding of the additive genetic factors which affect selection of cone chemistry, yield and agronomic characteristics in hop, aiding in the future development of improved cultivars. PMID:24524684

  20. Study of one-dimensional electron hopping and its effects on ESR line shape

    SciTech Connect

    Tang, Jau; Dikshit, S.N.; Norris, J.R. |

    1997-08-01

    Random hopping processes between discrete sites along a finite open chain or around a closed finite loop are examined. Closed form formulae are prescribed for the dependence of the ESR (electron spin resonance) line shape on the chain length and hopping rate. Significant differences between the closed loop and open chain are demonstrated. Deviation at short time from the results of diffusion in a continuum is presented.

  1. HOPS: a novel cAMP-dependent shuttling protein involved in protein synthesis regulation.

    PubMed

    Della Fazia, Maria Agnese; Castelli, Marilena; Bartoli, Daniela; Pieroni, Stefania; Pettirossi, Valentina; Piobbico, Danilo; Viola-Magni, Mariapia; Servillo, Giuseppe

    2005-07-15

    The liver has the ability to autonomously regulate growth and mass. Following partial hepatectomy, hormones, growth factors, cytokines and their coupled signal transduction pathways have been implicated in hepatocyte proliferation. To understand the mechanisms responsible for the proliferative response, we studied liver regeneration by characterization of novel genes that are activated in residual hepatocytes. A regenerating liver cDNA library screening was performed with cDNA-subtracted probes derived from regenerating and normal liver. Here, we describe the biology of Hops (for hepatocyte odd protein shuttling). HOPS is a novel shuttling protein that contains an ubiquitin-like domain, a putative NES and a proline-rich region. HOPS is rapidly exported from the nucleus and is overexpressed during liver regeneration. Evidence shows that cAMP governs HOPS export in hepatocytes of normal and regenerating liver and is mediated via CRM-1. We demonstrate that HOPS binds to elongation factor eEF-1A and interferes in protein synthesis. HOPS overexpression in H-35-hepatoma and 3T3-NIH cells strongly reduces proliferation. PMID:16014383

  2. Condom Use and Hip Hop Culture: The Case of Urban Young Men in New York City

    PubMed Central

    Muñoz-Laboy, Miguel A.; Castellanos, Daniel H.; Haliburton, Chanel S.; del Aguila, Ernesto Vasquez; Weinstein, Hannah J.; Parker, Richard G.

    2008-01-01

    Objectives. We explored how young men’s perceptions of and participation in hip hop culture—urban social and artistic expressions, such as clothing style, breakdancing, graffiti, and rap music—and how contextual factors of the hip hop scene may be associated with their condom use, condom-use self-efficacy, and sense of community. Methods. We conducted a cross-sectional survey of 95 African American and Latino men aged 15 to 25 years as part of a 4-year ethnographic study in New York City. Results. Differences in young men’s perceptions of and levels of affiliation with hip hop culture were not statistically associated with differences in their sense of community or condom-use self-efficacy. Frequency of participation in the hip hop nightclub scene was the strongest factor negatively associated with condom use. Conclusions. Popular discourses on young men’s health risks often blame youths’ cultures such as the hip hop culture for increased risk practices but do not critically examine how risk emerges in urban young men’s lives and what aspects of youths’ culture can be protective. Further research needs to focus on contextual factors of risk such as the role of hip hop nightlife on increased HIV risk. PMID:18445799

  3. Prion protein binding to HOP modulates the migration and invasion of colorectal cancer cells.

    PubMed

    de Lacerda, Tonielli Cristina Sousa; Costa-Silva, Bruno; Giudice, Fernanda Salgueiredo; Dias, Marcos Vinicios Salles; de Oliveira, Gabriela Pintar; Teixeira, Bianca Luise; Dos Santos, Tiago Goss; Martins, Vilma Regina

    2016-06-01

    Colorectal cancer (CRC) is one of the most frequently diagnosed malignancies. The generation of conventional treatments has improved, but approximately 50 % of patients with CRC who undergo potentially curative surgery ultimately relapse and die, usually as a consequence of metastatic disease. Our previous findings showed that engagement of the cellular prion protein (PrP(C)) to its ligand HSP70/90 heat shock organizing protein (HOP) induces proliferation of glioblastomas. In addition, PrP(C) has been described as an important modulator of colorectal tumor growth. Here, we investigated the biological relevance of the PrP(C)-HOP interaction in CRC cells. We demonstrate that HOP induced the migration and invasion of CRC cell lines in a PrP(C)-dependent manner and that phosphorylation of the ERK1/2 pathway is a downstream mediator of these effects. Additionally, we show that a HOP peptide with the ability to bind PrP(C) and abolish the PrP(C)-HOP interaction inhibited the migration and invasion of CRC cells. Together, these data indicate that the disruption of the PrP(C)-HOP complex could be a potential therapeutic target for modulating the migratory and invasive cellular properties that lead to metastatic CRC. PMID:27112151

  4. No evidence hip joint angle modulates intrinsically produced stretch reflex in human hopping.

    PubMed

    Gibson, W; Campbell, A; Allison, G

    2013-09-01

    Motor output in activities such as walking and hopping is suggested to be mediated neurally by purported stretch reflex augmentation of muscle output. Reflex EMG activity during these tasks has been frequently investigated in the soleus muscle; with alterations in reflex amplitude being associated with changes in hip joint angle/phase of the gait cycle. Previous work has focussed on reflex activity induced by an artificial perturbation or by induction of H-reflexes. As such, it is currently unknown if stretch reflex activity induced intrinsically (as part of the task) is modulated by changes in hip joint angle. This study investigated whether hip joint angle modulated reflex EMG 'burst' activity during a hopping task performed on a custom-built partially reclined sleigh. Ten subjects participated; EMG and kinematic data (VICON motor capture system) was collected for each hop cycle. Participants completed 5 sets of 30s of self-paced hopping in (1) hip neutral and (2) hip 60° flexion conditions. There was no difference in EMG 'burst' activity or in sagittal plane kinematics (knee/ankle) in the hopping task between the two conditions. The results indicate that during a functional task such as hopping, changes in hip angle do not alter the stretch reflex-like activity associated with landing. PMID:23791780

  5. Energy efficient hopping with Hill-type muscle properties on segmented legs.

    PubMed

    Rosendo, Andre; Iida, Fumiya

    2016-01-01

    The intrinsic muscular properties of biological muscles are the main source of stabilization during locomotion, and superior biological performance is obtained with low energy costs. Man-made actuators struggle to reach the same energy efficiency seen in biological muscles. Here, we compare muscle properties within a one-dimensional and a two-segmented hopping leg. Different force-length-velocity relations (constant, linear, and Hill) were adopted for these two proposed models, and the stable maximum hopping heights from both cases were used to estimate the cost of hopping. We then performed a fine-grained analysis during landing and takeoff of the best performing cases, and concluded that the force-velocity Hill-type model is, at maximum hopping height, the most efficient for both linear and segmented models. While hopping at the same height the force-velocity Hill-type relation outperformed the linear relation as well. Finally, knee angles between 60° and 90° presented a lower energy expenditure than other morphologies for both Hill-type and constant relations during maximum hopping height. This work compares different muscular properties in terms of energy efficiency within different geometries, and these results can be applied to decrease energy costs of current actuators and robots during locomotion. PMID:27070710

  6. Random free energy barrier hopping model for ac conduction in chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Murti, Ram; Tripathi, S. K.; Goyal, Navdeep; Prakash, Satya

    2016-03-01

    The random free energy barrier hopping model is proposed to explain the ac conductivity (σac) of chalcogenide glasses. The Coulomb correlation is consistently accounted for in the polarizability and defect distribution functions and the relaxation time is augmented to include the overlapping of hopping particle wave functions. It is observed that ac and dc conduction in chalcogenides are due to same mechanism and Meyer-Neldel (MN) rule is the consequence of temperature dependence of hopping barriers. The exponential parameter s is calculated and it is found that s is subjected to sample preparation and measurement conditions and its value can be less than or greater than one. The calculated results for a - Se, As2S3, As2Se3 and As2Te3 are found in close agreement with the experimental data. The bipolaron and single polaron hopping contributions dominates at lower and higher temperatures respectively and in addition to high energy optical phonons, low energy optical and high energy acoustic phonons also contribute to the hopping process. The variations of hopping distance with temperature is also studied. The estimated defect number density and static barrier heights are compared with other existing calculations.

  7. Electrochemical versus spectrophotometric assessment of antioxidant activity of hop (Humulus lupulus L.) products and individual compounds.

    PubMed

    Gorjanović, Stanislava; Pastor, Ferenc T; Vasić, Radica; Novaković, Miroslav; Simonović, Mladen; Milić, Sonja; Sužnjević, Desanka

    2013-09-25

    Antioxidant (AO) activity of extracts of hop cones (Serbian domestic varieties) and commercial hop products (Saaz, Spalter, Spalter select, and Magnum pellets) was determined by parallel application of recently developed direct current (DC) polarographic and widely used DPPH assay. Correlations between 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging and total phenolics (TPC) determined by the Folin-Ciocalteu assay (FC) (0.99), and between H2O2 scavenging (HPS) and humulone content (H) determined by conductometric method (0.94), total resins (TR) (0.85), and hop storage index (HIS) (-0.90), were found statistically significant at p < 0.05 level while complete lack of HPS correlation with TPC and DPPH was observed. To obtain an insight into differences between results of AO assays applied, activity of individual compounds, prevalent hop phenolics, and bitter acids was determined. By far superior HPS activity of humulone was followed by catechin, quercetin, xanthohumol, lupulone, and rutin. In contrast, DPPH scavenging activity of phenolics (quercetin > catechin > rutin > xantohumol) was found substantially higher than activity of bitter acids. According to ferric reducing antioxidant power (FRAP) and scavenging of 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), higher AO activity was ascribed to phenolics, while almost neglecting humulone. Besides reliability, low cost, and an easy-to-handle procedure, an ability to recognize humulone as the major contributor of hop AO activity could allow DC polarographic assay to be applied in analysis of various hop-derived products. PMID:23971792

  8. Scaffold hopping approach on the route to selective tankyrase inhibitors

    PubMed Central

    Liscio, Paride; Carotti, Andrea; Asciutti, Stefania; Ferri, Martina; Pires, Maira M.; Valloscuro, Sara; Ziff, Jacob; Clark, Neil R.; Macchiarulo, Antonio; Aaronson, Stuart A.; Pellicciari, Roberto; Camaioni, Emidio

    2015-01-01

    A virtual screening procedure was applied to identify new tankyrase inhibitors. Through pharmacophore screening of a compounds collection from the SPECS database, the methoxy[l]benzothieno[2,3-c]quinolin-6(5H)-one scaffold was identified as nicotinamide mimetic able to inhibit tankyrase activity at low micromolar concentration. In order to improve potency and selectivity, tandem structure-based and scaffold hopping approaches were carried out over the new scaffold leading to the discovery of the 2-(phenyl)-3H-benzo[4,5]thieno[3,2-d]pyrimidin-4-one as powerful chemotype suitable for tankyrase inhibition. The best compound 2-(4-tert-butyl-phenyl)-3H-benzo[4,5]thieno[3,2-d]pyrimidin-4-one (23) displayed nanomolar potencies (IC50s TNKS-1 = 21 nM and TNKS-2= 29 nM) and high selectivity when profiled against several other PARPs. Furthermore, a striking Wnt signaling, as well as cell growth inhibition, was observed assaying 23 in DLD-1 cancer cells. PMID:25299683

  9. Pinned vortex hopping in a neutron star crust

    NASA Astrophysics Data System (ADS)

    Haskell, B.; Melatos, A.

    2016-09-01

    The motion of superfluid vortices in a neutron star crust is at the heart of most theories of pulsar glitches. Pinning of vortices to ions can decouple the superfluid from the crust and create a reservoir of angular momentum. Sudden large-scale unpinning can lead to an observable glitch. In this paper, we investigate the scattering of a free vortex off a pinning potential and calculate its mean free path, in order to assess whether unpinned vortices can skip multiple pinning sites and come close enough to their neighbours to trigger avalanches, or whether they simply hop from one pinning site to its neighbour, giving rise to a more gradual creep. We find that there is a significant range of parameter space in which avalanches can be triggered, thus supporting the hypothesis that they may lie at the origin of pulsar glitches. For realistic values of the pinning force and superfluid drag parameters, we find that avalanches are more likely in the higher density regions of the crust where pinning is stronger. Physical differences in stellar parameters, such as mass and temperature, may lead to a switch between creep-like motion and avalanches, explaining the different characteristics of glitching pulsars.

  10. Revised Basin Hopping Monte Carlo Algorithm Applied for Nanoparticles

    NASA Astrophysics Data System (ADS)

    da Silva, Juarez L. F.; Rondina, Gustavo G.

    2013-03-01

    The Basin Hopping Monte Carlo (BHMC) algorithm has been very successful in obtaining the atomic structure of nanoparticles (NPs), however, its application for unbiased randomly initialized NPs have been restricted to few hundreds atoms employing empirical pair-potentials (EPP) and for small clusters employing first-principles interacting potentials based on density functional theory (DFT). In this talk, we will present our suggestions for bringing improvements to the the BHMC algorithm, which successfully extend its application for relatively large systems employing EPP and DFT potenticals. Using our implementation from scratch, we have found all the reported putative minimum energy configurations for Lennard-Jones and Sutton-Chen EPPs (N = 2 - 147, 200, 250, 300,..., 1000). We addressed also binary systems described by the Lennard-Jones or Sutton-Chen empirical potentials, and excellent results have been obtained. Finally, our revised BHMC implementation was combined with DFT potentials (FHI-AIMS), which was employed to study the atomic structure of Al clusters from 2 - 55 atoms in the neutral and charged states. Thus, our results indicate the our suggestions provide an important contribution to improve the quality of the BHMC results employing EPP or DFT potentials. We thank Sao Paulo Science Foundation (FAPESP)

  11. Impulsive movements lead to high hops on sand

    NASA Astrophysics Data System (ADS)

    Aguilar, Jeffrey; Goldman, Daniel I.

    2014-03-01

    Various animals exhibit locomotive behaviors (like sprinting and hopping) involving transient bursts of actuation coupled to the ground through internal elastic elements. The performance of such maneuvers is subject to reaction forces on the feet from the environment. On substrates like dry granular media, the laws that govern these forces are not fully understood, and can vary with foot size and shape, material compaction (measured by the volume fraction ϕ) and intrusion kinematics. To gain insight into how such interactions affect jumps on granular media, we study the performance of an actuated spring mass robot. We compare performance between two jump strategies: a single-cycle sine-wave actuation (a ``single jump'') and this actuation preceded by an impulsive preload (a ``preload jump''). We vary ϕ for both strategies, and find that ϕ significantly affects performance: we observe a 200% increase in the single jump height with only a 5% increase in volume fraction using a 7.62 cm diameter flat foot. The preload jump outperforms the single jump height by 150% for all ϕ. We hypothesize that this increase in performance results from higher intrusion velocities and accelerations associated with the preload. NSF POLS CAREER, Burroughs Wellcome Fund, and ARO.

  12. Surface hopping investigation of benzophenone excited state dynamics.

    PubMed

    Favero, Lucilla; Granucci, Giovanni; Persico, Maurizio

    2016-04-21

    We present a simulation of the photodynamics of benzophenone for the first 20 ps after n →π* excitation, performed by trajectory surface hopping calculations with on-the-fly semiempirical determination of potential energy surfaces and electronic wavefunctions. Both the dynamic and spin-orbit couplings are taken into account, and time-resolved fluorescence emission is also simulated. The computed decay time of the S1 state is in agreement with experimental observations. The direct S1→ T1 intersystem crossing (ISC) accounts for about 2/3 of the S1 decay rate. The remaining 1/3 goes through T2 or higher triplets. The nonadiabatic transitions within the triplet manifold are much faster than ISC and keep the population of T1 at about 3/4 of the total triplet population, and that of the other states (mainly T2) at 1/4. Two internal coordinates are vibrationally active immediately after n →π* excitation: one is the C[double bond, length as m-dash]O stretching and the other one is a combination of the conrotatory torsion of phenyl rings and of bending involving the carbonyl C atom. The period of the torsion-bending mode coincides with oscillations in the time-resolved photoelectron spectra of Spighi et al. and substantially confirms their assignment. PMID:27031566

  13. Pinned vortex hopping in a neutron star crust

    NASA Astrophysics Data System (ADS)

    Haskell, B.; Melatos, A.

    2016-06-01

    The motion of superfluid vortices in a neutron star crust is at the heart of most theories of pulsar glitches. Pinning of vortices to ions can decouple the superfluid from the crust and create a reservoir of angular momentum. Sudden large scale unpinning can lead to an observable glitch. In this paper we investigate the scattering of a free vortex off a pinning potential and calculate its mean free path, in order to assess whether unpinned vortices can skip multiple pinning sites and come close enough to their neighbours to trigger avalanches, or whether they simply hop from one pinning site to its neighbour, giving rise to a more gradual creep. We find that there is a significant range of parameter space in which avalanches can be triggered, thus supporting the hypothesis that they may lie at the origin of pulsar glitches. For realistic values of the pinning force and superfluid drag parameters we find that avalanches are more likely in the higher density regions of the crust where pinning is stronger. Physical differences in stellar parameters, such as mass and temperature, may lead to a switch between creep-like motion and avalanches, explaining the different characteristics of glitching pulsars.

  14. Acoustic positioning using a tetrahedral ultrashort baseline array of an acoustic modem source transmitting frequency-hopped sequences.

    PubMed

    Beaujean, Pierre-Philippe J; Mohamed, Asif I; Warin, Raphael

    2007-01-01

    Acoustic communications and positioning are vital aspects of unmanned underwater vehicle operations. The usage of separate units on each vehicle has become an issue in terms of frequency bandwidth, space, power, and cost. Most vehicles rely on acoustic modems transmitting frequency-hopped multiple frequency-shift keyed sequences for command-and-control operations, which can be used to locate the vehicle with a good level of accuracy without requiring extra signal transmission. In this paper, an ultrashort baseline acoustic positioning technique has been designed, simulated, and tested to locate an acoustic modem source in three dimensions using a tetrahedral, half-wavelength acoustic antenna. The position estimation is performed using the detection sequence contained in each message, which is a series of frequency-hopped pulses. Maximum likelihood estimation of azimuth and elevation estimation is performed using a varying number of pulse and various signal-to-noise ratios. Simulated and measured position estimation error match closely, and indicate that the accuracy of this system improves dramatically as the number of pulses processed increases, given a fixed signal-to-noise ratio. PMID:17297770

  15. Solution Structure and DNA-binding Properties of the Winged Helix Domain of the Meiotic Recombination HOP2 Protein*

    PubMed Central

    Moktan, Hem; Guiraldelli, Michel F.; Eyster, Craig A.; Zhao, Weixing; Lee, Chih-Ying; Mather, Timothy; Camerini-Otero, R. Daniel; Sung, Patrick; Zhou, Donghua H.; Pezza, Roberto J.

    2014-01-01

    The HOP2 protein is required for efficient double-strand break repair which ensures the proper synapsis of homologous chromosomes and normal meiotic progression. We previously showed that in vitro HOP2 shows two distinctive activities: when it is incorporated into a HOP2-MND1 heterodimer, it stimulates DMC1 and RAD51 recombination activities, and the purified HOP2 alone is proficient in promoting strand invasion. The structural and biochemical basis of HOP2 action in recombination are poorly understood; therefore, they are the focus of this work. Herein, we present the solution structure of the amino-terminal portion of mouse HOP2, which contains a typical winged helix DNA-binding domain. Together with NMR spectral changes in the presence of double-stranded DNA, protein docking on DNA, and mutation analysis to identify the amino acids involved in DNA coordination, our results on the three-dimensional structure of HOP2 provide key information on the fundamental structural and biochemical requirements directing the interaction of HOP2 with DNA. These results, in combination with mutational experiments showing the role of a coiled-coil structural feature involved in HOP2 self-association, allow us to explain important aspects of the function of HOP2 in recombination. PMID:24711446

  16. [Portable High-Precision System for CH4 Concentration Detection in Mines based on the Laser Mode-Hopping].

    PubMed

    Lu, Xu-tao; Li, Jing; Lü, Hai-feng

    2015-03-01

    In order to detect rapid, portable concentration of methane in the mine, meanwhile, the system included a high sensitivity and a long working period, designed differential optical absorption spectroscopy method based on mode-hopping of semiconductor laser, and established wireless detection system for concentration of methane in the mine. Output wavelengths of the semiconductor laser occurred mode-hopping by modulation current of the system, so it obtained the two wavelengths close to the laser, and one is on the characteristic absorption peak of methane, while the other is not substantially absorbed. When the two beams of light were illuminated test chamber, methane concentration of the gas chamber was solved by Bill Lambert law with the difference of the light intensity between the two beams. Light source used DFB single mode semiconductor laser from Japan Anritsu company. Experimental results show that, when the modulation current increased from 20.0 to 60.0 mA, output wavelength occurred mode-hopping when the modulation current reached 48.3 mA, and output wavelength changed to 1 651.020 nm from 1 650.888 nm. By HITRAN spectrum database, it showed that the position of the wavelength 1 650.888 nm can be used for characteristic absorption peaks, while the wavelength 1 651.020 nm was suitable for reference wavelength. On this basis, the standard concentrations of methane gas was tested in the sealed container, test data of the system was compared to the H-BD5GD410-HC portable methane detector. Test results of the system and the H-BD5GD410-HC portable methane detector were similar, but with the constant concentration increased, the detection error of the system is relatively stable, slightly better than the portable methane detector. Detection error of system were less than 0.050%, under the conditions that there were without the use of expensive phase lock or inspection phase circuit, to achieve the accuracy of better than 0.10% concentration of methane detected in

  17. a Study of a Two-Dimensional Electron System in the Variable-Range Hopping Regime

    NASA Astrophysics Data System (ADS)

    Hu, Xuelong

    A two-dimensional electron system is investigated in a gated heterostructure of GaAs/rm Al _{x}Ga_{1-x}As in the variable-range hopping regime. We report the first convincing evidence of a Coulomb gap in the density of states in a two-dimensional electron system and the screening of the Coulomb gap by a metallic gate for large hopping lengths. The Coulomb gap in the density of states is observed from measurements of the hopping conductivity. For large hopping lengths, Mott hopping is observed. The general expression for the hopping conductivity can be described in the form sigma_{xx} = sigma_1(T_{p}/T)^ {0.8} exp(-T_{p}/T) ^{p}, with p = 1/2 in the Coulomb gap and p = 1/3 in the Mott hopping regimes, respectively. For the temperature range investigated the transition between the Coulomb gap and Mott hopping regimes occurs at localization lengths in the range of 1 mum, which is about three times the separation of electron layer from the metallic gate. The behavior of the transition is in good agreement with the theoretical predictions by Aleiner and Shklovskii. The scaled conductivity prefactor sigma_1 is found to be independent of magnetic field but dependent on the degree of disorder. A divergence of the dielectric constant with localization length is not observed in this experiment. The dependence of the localization length on the electron density is consistent with the scaling theory of localization. A giant negative magnetoresistance with R(0)/R(B) as great as 100 is observed in the variable-range hopping regime at 24 mK. The experiment agrees with the quantum interference model in the sense that the magnetoresistance varies with the magnetic field as ln(R(B)/R(0)) = - gamma r_{M}/l_{B} ~ - B^{1/2} at low fields, where r_{M} is the Mott hopping length and l_ {B} = sqrt{eB/h} is the magnetic length. The numerical parameter gamma extrapolated from the experiment increases with an increase in the degree of disorder. This contradicts the prediction from a computer

  18. Hip-Hop as a Resource for Understanding the Urban Context: A Review of Christopher Edmin's--Science Education for the Hip-Hop Generation, Sense Publishers, Rotterdam, 2010

    ERIC Educational Resources Information Center

    Brown, Bryan

    2010-01-01

    This review explores Edmin's "Science education for the hip-hop generation" by documenting how he frames hip-hop as a means to access urban student culture. He argues that hip-hop is more than a mere music genre, but rather a culture that provides young people with ways of connecting to the world. Two primary ideas emerged as central to his work.…

  19. Hip-Hop High School: A Study of the Attitudes, Beliefs and Perceptions of Suburban High School Faculty towards Representation of the Hip-Hop Culture

    ERIC Educational Resources Information Center

    Rowland, Ronald K.

    2011-01-01

    Research historically has demonstrated that a generational disconnect between the popular cultures from which students and teachers define normative behavior can impact classroom management and student learning. The purpose of this study was to examine attitudes, beliefs and perceptions of high school faculty toward the hip-hop culture and its…

  20. ATPase Activity and ATP-dependent Conformational Change in the Co-chaperone HSP70/HSP90-organizing Protein (HOP)*

    PubMed Central

    Yamamoto, Soh; Subedi, Ganesh Prasad; Hanashima, Shinya; Satoh, Tadashi; Otaka, Michiro; Wakui, Hideki; Sawada, Ken-ichi; Yokota, Shin-ichi; Yamaguchi, Yoshiki; Kubota, Hiroshi; Itoh, Hideaki

    2014-01-01

    Co-chaperones help to maintain cellular homeostasis by modulating the activities of molecular chaperones involved in protein quality control. The HSP70/HSP90-organizing protein (HOP) is a co-chaperone that cooperates with HSP70 and HSP90 in catalysis of protein folding and maturation in the cytosol. We show here that HOP has ATP-binding activity comparable to that of HSP70/HSP90, and that HOP slowly hydrolyzes ATP. Analysis of deletion mutants revealed that the ATPase domain of HOP is in the N-terminal TPR1-DP1-TPR2A segment. In addition, HOP changes its conformation in the presence of ATP. These results indicate that HOP is a unique co-chaperone that undergoes an ATP-dependent conformational change. PMID:24535459

  1. Chemical transformations of characteristic hop secondary metabolites in relation to beer properties and the brewing process: a review.

    PubMed

    Steenackers, Bart; De Cooman, Luc; De Vos, Dirk

    2015-04-01

    The annual production of hops (Humulus lupulus L.) exceeds 100,000 mt and is almost exclusively consumed by the brewing industry. The value of hops is attributed to their characteristic secondary metabolites; these metabolites are precursors which are transformed during the brewing process into important bittering, aromatising and preservative components with rather low efficiency. By selectively transforming these components off-line, both their utilisation efficiency and functionality can be significantly improved. Therefore, the chemical transformations of these secondary metabolites will be considered with special attention to recent advances in the field. The considered components are the hop alpha-acids, hop beta-acids and xanthohumol, which are components unique to hops, and alpha-humulene and beta-caryophyllene, sesquiterpenes which are highly characteristic of hops. PMID:25442616

  2. Floquet surface hopping: Laser-driven dissociation and ionization dynamics of H2 +

    NASA Astrophysics Data System (ADS)

    Fiedlschuster, T.; Handt, J.; Schmidt, R.

    2016-05-01

    A quantum-classical approach is developed to describe the strong-field molecular dynamics of H2 +, taking into account all degrees of freedom and simultaneously dissociation as well as ionization. The electron and nuclei are treated correlated, by propagating the nuclei stochastically on potential energy surfaces. It is demonstrated that Floquet surface hopping (FSH) is particularly well suited to describe the laser-driven dynamics. The method is tested against exact solutions of the time-dependent Schrödinger equation, where available. In addition, the FSH results are in excellent agreement with recent experimental data of the dissociation and ionization dynamics of H2 +. As an additional issue of this work, the primary importance of the focal volume average is worked out for the understanding of experimental results. It determines the gross features of the experimental spectra and provides also a natural explanation of the puzzling saturation effect in the dissociation spectra, observed experimentally. Future applications and further extensions of the method are discussed.

  3. Frequency-hopped multiple access communications with coding and side information

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Chao, Yuying

    1992-02-01

    The authors consider frequency-hopped spread-spectrum multiple-access communications using M-ary modulation and error-correction coding. The major concerns are multiple-access interference and the network capacity in terms of the number of users that can transmit simultaneously for a given level of codeword error probability. Block coding is studied in detail. The authors first consider the use of Q-ary Reed-Solomon (RS) codes in combination with M-ary modulation with mismatched alphabets so that Q is greater than M. It is shown that the network capacity is drastically reduced in comparison with the system with matched alphabets. As a remedy, the use of matched M-ary BCH codes is proposed as an alternative to mismatched RS codes. It is shown that when the number of users in the system is large, a BCH code outperforms an RX code with a comparable code rate and decoding complexity. The authors consider the use of a robust technique for generation of reliable side information based on a ratio-threshold test. They analyze its performance in conjunction with MFSK and error-erasure correction decoding. It is shown that this nonideal ratio-threshold method can increase the network capacity in comparison with the system with perfect side information.

  4. Longitudinal hopping in intervehicle communication: Theory and simulations on modeled and empirical trajectory data

    NASA Astrophysics Data System (ADS)

    Thiemann, Christian; Treiber, Martin; Kesting, Arne

    2008-09-01

    Intervehicle communication enables vehicles to exchange messages within a limited broadcast range and thus self-organize into dynamical and geographically embedded wireless ad hoc networks. We study the longitudinal hopping mode in which messages are transported using equipped vehicles driving in the same direction as a relay. Given a finite communication range, we investigate the conditions where messages can percolate through the network, i.e., a linked chain of relay vehicles exists between the sender and receiver. We simulate message propagation in different traffic scenarios and for different fractions of equipped vehicles. Simulations are done with both, modeled and empirical traffic data. These results are used to test the limits of applicability of an analytical model assuming a Poissonian distance distribution between the relays. We found a good agreement for homogeneous traffic scenarios and sufficiently low percentages of equipped vehicles. For higher percentages, the observed connectivity was higher than that of the model while in stop-and-go traffic situations it was lower. We explain these results in terms of correlations of the distances between the relay vehicles. Finally, we introduce variable transmission ranges and found that this additional stochastic component generally increased connectivity compared to a deterministic transmission with the same mean.

  5. Scaffold hopping using clique detection applied to reduced graphs.

    PubMed

    Barker, Edward J; Buttar, David; Cosgrove, David A; Gardiner, Eleanor J; Kitts, Paula; Willett, Peter; Gillet, Valerie J

    2006-01-01

    Similarity-based methods for virtual screening are widely used. However, conventional searching using 2D chemical fingerprints or 2D graphs may retrieve only compounds which are structurally very similar to the original target molecule. Of particular current interest then is scaffold hopping, that is, the ability to identify molecules that belong to different chemical series but which could form the same interactions with a receptor. Reduced graphs provide summary representations of chemical structures and, therefore, offer the potential to retrieve compounds that are similar in terms of their gross features rather than at the atom-bond level. Using only a fingerprint representation of such graphs, we have previously shown that actives retrieved were more diverse than those found using Daylight fingerprints. Maximum common substructures give an intuitively reasonable view of the similarity between two molecules. However, their calculation using graph-matching techniques is too time-consuming for use in practical similarity searching in larger data sets. In this work, we exploit the low cardinality of the reduced graph in graph-based similarity searching. We reinterpret the reduced graph as a fully connected graph using the bond-distance information of the original graph. We describe searches, using both the maximum common induced subgraph and maximum common edge subgraph formulations, on the fully connected reduced graphs and compare the results with those obtained using both conventional chemical and reduced graph fingerprints. We show that graph matching using fully connected reduced graphs is an effective retrieval method and that the actives retrieved are likely to be topologically different from those retrieved using conventional 2D methods. PMID:16562978

  6. Short-Term Effects of Patellar Kinesio Taping on Pain and Hop Function in Patients With Patellofemoral Pain Syndrome

    PubMed Central

    Freedman, Scott R.; Brody, Lori Thein; Rosenthal, Michael; Wise, Justin C.

    2014-01-01

    Background: Patellofemoral pain syndrome (PFPS) is the most prevalent orthopaedic condition among physically active individuals, contributing to an estimated 30% to 40% of all sports medicine visits. Techniques using Kinesio Tape (KT) have become increasingly popular; however, there has been scant research supporting its use on patients with PFPS. Hypothesis: The use of patellar KT to treat patients with PFPS will provide a statistically significant improvement in short-term pain and single-leg hop measures as compared with sham placement of KT. Study Design: Nonrandomized controlled clinical trial with repeated-measures design. Level of Evidence: Level 3. Methods: Forty-nine subjects (41 females, 8 males) between the ages of 12 and 24 years with PFPS participated in this study. Each subject underwent patellar kinesio taping with both experimental and sham applications while completing 4 functional tasks and the single-leg triple jump test (STJT). The treatment outcome was analyzed using separate paired t tests to measure improvement on a numeric pain rating scale. A 2-way, 2 × 2 analysis of variance was used to analyze the relationship between taping condition (experimental vs sham) and side (involved vs uninvolved) for STJT scores. Results: Separate paired t tests found step-up, step-down, and STJT pain improvement statistically significant between taping conditions. The 2-factor analysis of variance yielded a significant main effect for taping condition, but the main effect for side was not significant. The interaction between taping condition and side was significant. This showed there was little change in STJT distance between repeated measures performed on the untaped, noninvolved leg. However, subjects’ STJT distances were significantly greater for the experimental KT application than the sham application for the involved side. Conclusion: Patellar kinesio taping provided an immediate and statistically significant improvement in pain and single-leg hop

  7. Pseudomonas syringae type III effector HopAF1 suppresses plant immunity by targeting methionine recycling to block ethylene induction

    PubMed Central

    Washington, Erica J.; Mukhtar, M. Shahid; Finkel, Omri M.; Wan, Li; Kieber, Joseph J.; Dangl, Jeffery L.

    2016-01-01

    HopAF1 is a type III effector protein of unknown function encoded in the genomes of several strains of Pseudomonas syringae and other plant pathogens. Structural modeling predicted that HopAF1 is closely related to deamidase proteins. Deamidation is the irreversible substitution of an amide group with a carboxylate group. Several bacterial virulence factors are deamidases that manipulate the activity of specific host protein substrates. We identified Arabidopsis methylthioadenosine nucleosidase proteins MTN1 and MTN2 as putative targets of HopAF1 deamidation. MTNs are enzymes in the Yang cycle, which is essential for the high levels of ethylene biosynthesis in Arabidopsis. We hypothesized that HopAF1 inhibits the host defense response by manipulating MTN activity and consequently ethylene levels. We determined that bacterially delivered HopAF1 inhibits ethylene biosynthesis induced by pathogen-associated molecular patterns and that Arabidopsis mtn1 mtn2 mutant plants phenocopy the effect of HopAF1. Furthermore, we identified two conserved asparagines in MTN1 and MTN2 from Arabidopsis that confer loss of function phenotypes when deamidated via site-specific mutation. These residues are potential targets of HopAF1 deamidation. HopAF1-mediated manipulation of Yang cycle MTN proteins is likely an evolutionarily conserved mechanism whereby HopAF1 orthologs from multiple plant pathogens contribute to disease in a large variety of plant hosts. PMID:27274076

  8. Differential regulation of detoxification enzymes in hepatic and mammary tissue by hops (Humulus lupulus) in vitro and in vivo

    PubMed Central

    Dietz, Birgit M.; Hagos, Ghenet K.; Eskra, Jillian N.; Wijewickrama, Gihani T.; Anderson, Jeffrey R.; Nikolic, Dejan; Guo, Jian; Wright, Brian; Chen, Shao-Nong; Pauli, Guido F.; van Breemen, Richard B.; Bolton, Judy L.

    2013-01-01

    Scope Hops contain the phytoestrogen, 8-prenylnaringenin, and the cytoprotective compound, xanthohumol (XH). XH induces the detoxification enzyme, NAD(P)H-quinone oxidoreductase (NQO1) in vitro; however, the tissue distribution of XH and 8-prenylnaringenin and their tissue specific activity have not been analyzed. Methods and results A standardized hop extract (p.o.) and XH (s.c.) were administered to Sprague-Dawley rats over four days. LC-MS-MS analysis of plasma, liver and mammary gland revealed that XH accumulated in liver and mammary glands. Compared with the low level in the original extract, 8-prenylnaringenin was enriched in the tissues. Hops and XH induced NQO1 in the liver, while only hops reduced NQO1 activity in the mammary gland. Mechanistic studies revealed that hops modulated NQO1 through three mechanisms. In liver cells, 1) XH modified Keap1 leading to Nrf2 translocation and antioxidant response element (ARE) activation; 2) hop-mediated ARE induction was partially mediated through phosphorylation of Nrf2 by PKC; 3) in breast cells, 8-prenylnaringenin reduced NQO1 likely through binding to ERα, recruiting Nrf2, and downregulating ARE-regulated genes. Conclusions XH and 8-prenylnaringenin in dietary hops are bioavailable to the target tissues. While hops and XH might be cytoprotective in the liver, 8-prenylnaringenin seems responsible for hop-mediated NQO1 reduction in the mammary gland. PMID:23512484

  9. HOP'N after-school project: an obesity prevention randomized controlled trial

    PubMed Central

    2010-01-01

    Background This paper reports the primary outcomes of the Healthy Opportunities for Physical Activity and Nutrition (HOP'N) after-school project, which was an effectiveness trial designed to evaluate the prevention of childhood obesity through building the capacity of after-school staff to increase physical activity (PA) and fruit and vegetable (FV) opportunities. Methods We conducted a three-year, nested cross-sectional group randomized controlled effectiveness trial. After a baseline assessment year (2005-2006), schools and their after-school programs were randomized to the HOP'N after-school program (n = 4) or control (n = 3), and assessed for two subsequent years (intervention year 1, 2006-2007; intervention year 2, 2007-2008). Across the three years, 715 fourth grade students, and 246 third and fourth grade after-school program participants were included in the study. HOP'N included community government human service agency (Cooperative Extension) led community development efforts, a three-time yearly training of after-school staff, daily PA for 30 minutes following CATCH guidelines, a daily healthful snack, and a weekly nutrition and PA curriculum (HOP'N Club). Child outcomes included change in age- and gender-specific body mass index z-scores (BMIz) across the school year and PA during after-school time measured by accelerometers. The success of HOP'N in changing after-school program opportunities was evaluated by observations over the school year of after-school program physical activity sessions and snack FV offerings. Data were analyzed in 2009. Results The intervention had no impact on changes in BMIz. Overweight/obese children attending HOP'N after-school programs performed 5.92 minutes more moderate-to-vigorous PA per day after intervention, which eliminated a baseline year deficit of 9.65 minutes per day (p < 0.05) compared to control site overweight/obese children. Active recreation program time at HOP'N sites was 23.40 minutes (intervention year 1

  10. A study on a wheel-based stair-climbing robot with a hopping mechanism

    NASA Astrophysics Data System (ADS)

    Kikuchi, Koki; Sakaguchi, Keisuke; Sudo, Takayuki; Bushida, Naoki; Chiba, Yasuhiro; Asai, Yuji

    2008-08-01

    In this study, we propose a simple hopping mechanism using the vibration of a two-degree-of-freedom system for a wheel-based stair-climbing robot. The robot, consisting of two bodies connected by springs and a wire, hops by releasing energy stored in the springs and quickly travels using wheels mounted in its lower body. The trajectories of the bodies during hopping change in accordance with the design parameters, such as the reduced mass of the two bodies, the mass ratio between the upper and lower bodies, the spring constant, the control parameters such as the initial contraction of the spring and the wire tension. This property allows the robot to quickly and economically climb up and down stairs, leap over obstacles, and landing softly without complex control. In this paper, the characteristics of hopping motion for the design and control parameters are clarified by both numerical simulations and experiments. Furthermore, using the robot design based on the results the abilities to hop up and down a step, leap over a cable, and land softly are demonstrated.

  11. Multi-Hop Localization Algorithm Based on Grid-Scanning for Wireless Sensor Networks*

    PubMed Central

    Wan, Jiangwen; Guo, Xiaolei; Yu, Ning; Wu, Yinfeng; Feng, Renjian

    2011-01-01

    For large-scale wireless sensor networks (WSNs) with a minority of anchor nodes, multi-hop localization is a popular scheme for determining the geographical positions of the normal nodes. However, in practice existing multi-hop localization methods suffer from various kinds of problems, such as poor adaptability to irregular topology, high computational complexity, low positioning accuracy, etc. To address these issues in this paper, we propose a novel Multi-hop Localization algorithm based on Grid-Scanning (MLGS). First, the factors that influence the multi-hop distance estimation are studied and a more realistic multi-hop localization model is constructed. Then, the feasible regions of the normal nodes are determined according to the intersection of bounding square rings. Finally, a verifiably good approximation scheme based on grid-scanning is developed to estimate the coordinates of the normal nodes. Additionally, the positioning accuracy of the normal nodes can be improved through neighbors’ collaboration. Extensive simulations are performed in isotropic and anisotropic networks. The comparisons with some typical algorithms of node localization confirm the effectiveness and efficiency of our algorithm. PMID:22163828

  12. Gastric Cancer and Helicobacter pylori: Impact of hopQII Gene.

    PubMed

    Kazemi, E; Kahrizi, D; Moradi, M T; Sohrabi, M; Yari, K

    2016-01-01

    The Helicobacter pylori is a Gram-negative, microaerophilic bacterium found usually in the stomach and use a number of mechanisms to survive in the stomach lumen. The presence of these bacteria in the stomach can lead to gastritis and reduction in stomach acid production. Acute inflammation can directly damage to the peripheral cells that are responsible for the secretion of acid. The risk of developing gastric carcinoma is associated to heterogeneity of Helicobacter pylori virulence factors. The HopQII is one of the outer membrane proteins involved in bacterial adherence to gastric mucosa and has been suggested to also play a role in the virulence of H. pylori. The purpose of the current study was to investigate the association between different H. pylori virulence hopQII allele and patients with gastroduodenal disorders. For this purpose 58 stomach biopsies of patients with gastric cancer and 100 saliva samples from healthy individuals were collected. Then genomic DNA was purified and PCR for was done for desired genes via specific primers. The H. pylori infections were diagnosed by PCR for GlmM gene. Then frequencies of hopQII+ and hopQII- genotypes was determined in H. pylori infected cases. Statistical analysis showed that there were not significant differences between healthy and diseased ones for genotype hopQII+. PMID:26950460

  13. HopW1 from Pseudomonas syringae Disrupts the Actin Cytoskeleton to Promote Virulence in Arabidopsis

    PubMed Central

    Cecchini, Nicolas M.; Li, Yujie; Lee, Min Woo; Kovar, David R.; Greenberg, Jean T.

    2014-01-01

    A central mechanism of virulence of extracellular bacterial pathogens is the injection into host cells of effector proteins that modify host cellular functions. HopW1 is an effector injected by the type III secretion system that increases the growth of the plant pathogen Pseudomonas syringae on the Columbia accession of Arabidopsis. When delivered by P. syringae into plant cells, HopW1 causes a reduction in the filamentous actin (F-actin) network and the inhibition of endocytosis, a known actin-dependent process. When directly produced in plants, HopW1 forms complexes with actin, disrupts the actin cytoskeleton and inhibits endocytosis as well as the trafficking of certain proteins to vacuoles. The C-terminal region of HopW1 can reduce the length of actin filaments and therefore solubilize F-actin in vitro. Thus, HopW1 acts by disrupting the actin cytoskeleton and the cell biological processes that depend on actin, which in turn are needed for restricting P. syringae growth in Arabidopsis. PMID:24968323

  14. Protein structure prediction using global optimization by basin-hopping with NMR shift restraints

    NASA Astrophysics Data System (ADS)

    Hoffmann, Falk; Strodel, Birgit

    2013-01-01

    Computational methods that utilize chemical shifts to produce protein structures at atomic resolution have recently been introduced. In the current work, we exploit chemical shifts by combining the basin-hopping approach to global optimization with chemical shift restraints using a penalty function. For three peptides, we demonstrate that this approach allows us to find near-native structures from fully extended structures within 10 000 basin-hopping steps. The effect of adding chemical shift restraints is that the α and β secondary structure elements form within 1000 basin-hopping steps, after which the orientation of the secondary structure elements, which produces the tertiary contacts, is driven by the underlying protein force field. We further show that our chemical shift-restraint BH approach also works for incomplete chemical shift assignments, where the information from only one chemical shift type is considered. For the proper implementation of chemical shift restraints in the basin-hopping approach, we determined the optimal weight of the chemical shift penalty energy with respect to the CHARMM force field in conjunction with the FACTS solvation model employed in this study. In order to speed up the local energy minimization procedure, we developed a function, which continuously decreases the width of the chemical shift penalty function as the minimization progresses. We conclude that the basin-hopping approach with chemical shift restraints is a promising method for protein structure prediction.

  15. Biological and Chemical Standardization of a Hop (Humulus lupulus) Botanical Dietary Supplement

    PubMed Central

    Krause, Elizabeth; Yuan, Yang; Hajirahimkhan, Atieh; Dong, Huali; Dietz, Birgit M.; Nikolic, Dejan; Pauli, Guido F.; Bolton, Judy L.; van Breemen, Richard B.

    2014-01-01

    Concerned about the safety of conventional estrogen replacement therapy, women are using botanical dietary supplements as alternatives for the management of menopausal symptoms such as hot flashes. Before botanical dietary supplements can be evaluated clinically for safety and efficacy, botanically authenticated and standardized forms are required. To address the demand for a standardized, estrogenic botanical dietary supplement, an extract of hops (Humulus lupulus, L.) was developed. Although valued in the brewing of beer, hop extracts are used as anxiolytics and hypnotics and have well established estrogenic constituents. Starting with a hop cultivar used in the brewing industry, spent hops (the residue remaining after extraction of bitter acids) were formulated into a botanical dietary supplement that was then chemically and biologically standardized. Biological standardization utilized the estrogen dependent induction of alkaline phosphatase in the Ishikawa cell line. Chemical standardization was based on the prenylated phenols in hops that included estrogenic 8-prenylnaringenin (8-PN), its isomer 6-prenylnaringenin (6-PN), and pro-estrogenic isoxanthohumol (IX) and its isomeric chalcone xanthohumol (XN), all of which were measured using high performance liquid chromatography-tandem mass spectrometry (LC/MS-MS). The product of this process was a reproducible botanical extract suitable for subsequent investigations of safety and efficacy. PMID:24861737

  16. Biological and chemical standardization of a hop (Humulus lupulus) botanical dietary supplement.

    PubMed

    Krause, Elizabeth; Yuan, Yang; Hajirahimkhan, Atieh; Dong, Huali; Dietz, Birgit M; Nikolic, Dejan; Pauli, Guido F; Bolton, Judy L; van Breemen, Richard B

    2014-06-01

    Concerned about the safety of conventional estrogen replacement therapy, women are using botanical dietary supplements as alternatives for the management of menopausal symptoms such as hot flashes. Before botanical dietary supplements can be evaluated clinically for safety and efficacy, botanically authenticated and standardized forms are required. To address the demand for a standardized, estrogenic botanical dietary supplement, an extract of hops (Humulus lupulus L.) was developed. Although valued in the brewing of beer, hop extracts are used as anxiolytics and hypnotics and have well-established estrogenic constituents. Starting with a hop cultivar used in the brewing industry, spent hops (the residue remaining after extraction of bitter acids) were formulated into a botanical dietary supplement that was then chemically and biologically standardized. Biological standardization utilized the estrogen-dependent induction of alkaline phosphatase in the Ishikawa cell line. Chemical standardization was based on the prenylated phenols in hops that included estrogenic 8-prenylnaringenin, its isomer 6-prenylnaringenin, and pro-estrogenic isoxanthohumol and its isomeric chalcone xanthohumol, all of which were measured using high-performance liquid chromatography-tandem mass spectrometry. The product of this process was a reproducible botanical extract suitable for subsequent investigations of safety and efficacy. PMID:24861737

  17. Hopping conduction in bismuth modified zinc vanadate glasses: An applicability of Mott's model

    NASA Astrophysics Data System (ADS)

    Punia, R.; Kundu, R. S.; Murugavel, S.; Kishore, N.

    2012-12-01

    The dc conductivity measured in a wide range of temperatures (room temperature to 533.16 K) for glass samples of compositions 50V2O5.xBi2O3.(50-x) ZnO; x = 0, 5, 10, 15, and 20, is discussed in this paper. The temperature dependent dc conductivity has been analyzed in the framework of various theoretical models, which describe the hopping conduction in disordered semiconducting systems. It has been observed that Mott's model of polaron hopping in transition metals is in good agreement with the experimental data in high as well as intermediate temperature regions. The various polaron hopping parameters have also been deduced. It has been ascertained by these estimated quantities and different approaches that the electrical conduction in present glass system is due to non-adiabatic variable range hopping of small polarons. Moreover, it has been found that Mott's and Greaves' variable range hopping models are in good agreement with the experimental data in the whole studied temperature range in the present investigation.

  18. Cascading multi-hop reservation and transmission in underwater acoustic sensor networks.

    PubMed

    Lee, Jae-Won; Cho, Ho-Shin

    2014-01-01

    The long propagation delay in an underwater acoustic channel makes designing an underwater media access control (MAC) protocol more challenging. In particular, handshaking-based MAC protocols widely used in terrestrial radio channels have been known to be inappropriate in underwater acoustic channels, because of the inordinately large latency involved in exchanging control packets. Furthermore, in the case of multi-hop relaying in a hop-by-hop handshaking manner, the end-to-end delay significantly increases. In this paper, we propose a new MAC protocol named cascading multi-hop reservation and transmission (CMRT). In CMRT, intermediate nodes between a source and a destination may start handshaking in advance for the next-hop relaying before handshaking for the previous node is completed. By this concurrent relaying, control packet exchange and data delivery cascade down to the destination. In addition, to improve channel utilization, CMRT adopts a packet-train method where multiple data packets are sent together by handshaking once. Thus, CMRT reduces the time taken for control packet exchange and accordingly increases the throughput. The performance of CMRT is evaluated and compared with that of two conventional MAC protocols (multiple-access collision avoidance for underwater (MACA-U) and MACA-U with packet trains (MACA-UPT)). The results show that CMRT outperforms other MAC protocols in terms of both throughput and end-to-end delay. PMID:25275349

  19. Identification of critical chemical features for Aurora kinase-B inhibitors using Hip-Hop, virtual screening and molecular docking

    NASA Astrophysics Data System (ADS)

    Sakkiah, Sugunadevi; Thangapandian, Sundarapandian; John, Shalini; Lee, Keun Woo

    2011-01-01

    This study was performed to find the selective chemical features for Aurora kinase-B inhibitors using the potent methods like Hip-Hop, virtual screening, homology modeling, molecular dynamics and docking. The best hypothesis, Hypo1 was validated toward a wide range of test set containing the selective inhibitors of Aurora kinase-B. Homology modeling and molecular dynamics studies were carried out to perform the molecular docking studies. The best hypothesis Hypo1 was used as a 3D query to screen the chemical databases. The screened molecules from the databases were sorted based on ADME and drug like properties. The selective hit compounds were docked and the hydrogen bond interactions with the critical amino acids present in Aurora kinase-B were compared with the chemical features present in the Hypo1. Finally, we suggest that the chemical features present in the Hypo1 are vital for a molecule to inhibit the Aurora kinase-B activity.

  20. An effector gene hopA1 influences on virulence, host specificity, and lifestyles of Pseudomonas cichorii JBC1.

    PubMed

    Hung, Nguyen Bao; Ramkumar, Gandhimani; Lee, Yong Hoon

    2014-10-01

    Pseudomonas cichorii is a devastating pathogen which infects a wide range of ornamental as well as agricultural crops worldwide. Characterization of virulence genes helps to understand pathogens' infection processes, which may lead to development of resistant crops. For functional validation of novel genes, we re-constructed pUCP18 vector with λ phage red operon and sacB gene (pUCP18_RedS), which simplified conventional marker exchange system. The effector gene hopA1 of P. cichorii JBC1 was marker exchanged with PCR product of kanamycin gene flanked by hopA1 flanking region using pUCP18_RedS. The virulence and internal growth of hopA1 defective mutant (ΔhopA1) in tomato seedlings was significantly reduced compared to wild type (WT) and hopA1 complemented strain (ΔhopA1::phopA1). The analysis on role of hopA1 in host range revealed that P. cichorii was hopA1-dependent to infect cabbage, tomato, soybean, hot pepper, and cucumber, but not melon and eggplant. Despite the similarity in growth pattern, the biofilm formation and swarming motility of ΔhopA1 were significantly reduced compared to WT and ΔhopA1::phopA1. The results of this study indicate that hopA1 plays a significant role not only in virulence and host specificity, but also motility and biofilm formation of P. cichorii which may influence the infection processes. PMID:25127676

  1. Interaction-induced hopping phase in driven-dissipative coupled photonic microcavities

    NASA Astrophysics Data System (ADS)

    Rodriguez, S. R. K.; Amo, A.; Sagnes, I.; Le Gratiet, L.; Galopin, E.; Lemaître, A.; Bloch, J.

    2016-06-01

    The Bose-Hubbard model (BHM) describes bosons hopping across sites and interacting on-site. Inspired by the success of BHM simulators with atoms in optical lattices, proposals for implementing the BHM with photons in coupled nonlinear cavities have recently emerged. Two coupled semiconductor microcavities constitute a model system where the hopping, interaction and decay of exciton polaritons--mixed light-matter quasiparticles--can be engineered in combination with site-selective coherent driving to implement the driven-dissipative two-site optical BHM. Here we explore the interplay of interference and nonlinearity in this system, in a regime where three distinct density profiles can be observed under identical driving conditions. We demonstrate how the phase acquired by polaritons hopping between cavities can be controlled through polariton-polariton interactions. Our results open new perspectives for synthesizing density-dependent gauge fields using polaritons in two-dimensional multicavity systems.

  2. Topological Properties of Electrons in Honeycomb Lattice with Detuned Hopping Energy

    NASA Astrophysics Data System (ADS)

    Wu, Long-Hua; Hu, Xiao

    2016-04-01

    Honeycomb lattice can support electronic states exhibiting Dirac energy dispersion, with graphene as the icon. We propose to derive nontrivial topology by grouping six neighboring sites of honeycomb lattice into hexagons and enhancing the inter-hexagon hopping energies over the intra-hexagon ones. We reveal that this manipulation opens a gap in the energy dispersion and drives the system into a topological state. The nontrivial topology is characterized by the index associated with a pseudo time-reversal symmetry emerging from the C6 symmetry of the hopping texture, where the angular momentum of orbitals accommodated on the hexagonal “artificial atoms” behaves as the pseudospin. The size of topological gap is proportional to the hopping-energy difference, which can be larger than typical spin-orbit couplings by orders of magnitude and potentially renders topological electronic transports available at high temperatures.

  3. Interaction-induced hopping phase in driven-dissipative coupled photonic microcavities.

    PubMed

    Rodriguez, S R K; Amo, A; Sagnes, I; Le Gratiet, L; Galopin, E; Lemaître, A; Bloch, J

    2016-01-01

    The Bose-Hubbard model (BHM) describes bosons hopping across sites and interacting on-site. Inspired by the success of BHM simulators with atoms in optical lattices, proposals for implementing the BHM with photons in coupled nonlinear cavities have recently emerged. Two coupled semiconductor microcavities constitute a model system where the hopping, interaction and decay of exciton polaritons-mixed light-matter quasiparticles-can be engineered in combination with site-selective coherent driving to implement the driven-dissipative two-site optical BHM. Here we explore the interplay of interference and nonlinearity in this system, in a regime where three distinct density profiles can be observed under identical driving conditions. We demonstrate how the phase acquired by polaritons hopping between cavities can be controlled through polariton-polariton interactions. Our results open new perspectives for synthesizing density-dependent gauge fields using polaritons in two-dimensional multicavity systems. PMID:27307038

  4. Interaction-induced hopping phase in driven-dissipative coupled photonic microcavities

    PubMed Central

    Rodriguez, S. R. K.; Amo, A.; Sagnes, I.; Le Gratiet, L.; Galopin, E.; Lemaître, A.; Bloch, J.

    2016-01-01

    The Bose-Hubbard model (BHM) describes bosons hopping across sites and interacting on-site. Inspired by the success of BHM simulators with atoms in optical lattices, proposals for implementing the BHM with photons in coupled nonlinear cavities have recently emerged. Two coupled semiconductor microcavities constitute a model system where the hopping, interaction and decay of exciton polaritons—mixed light-matter quasiparticles—can be engineered in combination with site-selective coherent driving to implement the driven-dissipative two-site optical BHM. Here we explore the interplay of interference and nonlinearity in this system, in a regime where three distinct density profiles can be observed under identical driving conditions. We demonstrate how the phase acquired by polaritons hopping between cavities can be controlled through polariton-polariton interactions. Our results open new perspectives for synthesizing density-dependent gauge fields using polaritons in two-dimensional multicavity systems. PMID:27307038

  5. Topological Properties of Electrons in Honeycomb Lattice with Detuned Hopping Energy

    PubMed Central

    Wu, Long-Hua; Hu, Xiao

    2016-01-01

    Honeycomb lattice can support electronic states exhibiting Dirac energy dispersion, with graphene as the icon. We propose to derive nontrivial topology by grouping six neighboring sites of honeycomb lattice into hexagons and enhancing the inter-hexagon hopping energies over the intra-hexagon ones. We reveal that this manipulation opens a gap in the energy dispersion and drives the system into a topological state. The nontrivial topology is characterized by the index associated with a pseudo time-reversal symmetry emerging from the C6 symmetry of the hopping texture, where the angular momentum of orbitals accommodated on the hexagonal “artificial atoms” behaves as the pseudospin. The size of topological gap is proportional to the hopping-energy difference, which can be larger than typical spin-orbit couplings by orders of magnitude and potentially renders topological electronic transports available at high temperatures. PMID:27076196

  6. Subunit Organisation of In Vitro Reconstituted HOPS and CORVET Multisubunit Membrane Tethering Complexes

    PubMed Central

    Guo, Zhong; Johnston, Wayne; Kovtun, Oleksiy; Mureev, Sergey; Bröcker, Cornelia; Ungermann, Christian; Alexandrov, Kirill

    2013-01-01

    Biochemical and structural analysis of macromolecular protein assemblies remains challenging due to technical difficulties in recombinant expression, engineering and reconstitution of multisubunit complexes. Here we use a recently developed cell-free protein expression system based on the protozoan Leishmania tarentolae to produce in vitro all six subunits of the 600 kDa HOPS and CORVET membrane tethering complexes. We demonstrate that both subcomplexes and the entire HOPS complex can be reconstituted in vitro resulting in a comprehensive subunit interaction map. To our knowledge this is the largest eukaryotic protein complex in vitro reconstituted to date. Using the truncation and interaction analysis, we demonstrate that the complex is assembled through short hydrophobic sequences located in the C-terminus of the individual Vps subunits. Based on this data we propose a model of the HOPS and CORVET complex assembly that reconciles the available biochemical and structural data. PMID:24312556

  7. On the statistical dependence of hits in frequency-hop multiple access

    NASA Astrophysics Data System (ADS)

    Frank, Colin D.; Pursley, Michael B.

    1990-09-01

    The statistical dependence of hits due to multiple-access interference in an asynchronous slow-frequency-hop packet radio network in which the radios employ memoryless hopping patterns is described. Models in which hits are conditionally independent given the number of interfering packets are investigated. It is shown that, if the conditional probability of a hit is chosen appropriately, the distribution function for the number of hits in a packet for these models can be used to compute upper and lower bounds on the true distribution function for the number of hits. Conditions are described for which these models can be used to compute upper and lower bounds on the codeword and packet error probabilities. If the ratio of the number of interfering packets to the number of frequency slots is held constant, hits in the asynchronous frequency-hop network are asymptotically independent in the limit as the number of frequency slots increases.

  8. Bose-Hubbard model with random impurities: Multiband and nonlinear hopping effects

    NASA Astrophysics Data System (ADS)

    Stasińska, Julia; Łacki, Mateusz; Dutta, Omjyoti; Zakrzewski, Jakub; Lewenstein, Maciej

    2014-12-01

    We investigate the phase diagrams of theoretical models describing bosonic atoms in a lattice in the presence of randomly localized impurities. By including multiband and nonlinear hopping effects we enrich the standard model containing only the chemical-potential disorder with the site-dependent hopping term. We compare the extension of the MI and the BG phase in both models using a combination of the local mean-field method and a Hartree-Fock-like procedure, as well as the Gutzwiller-ansatz approach. We show analytical argument for the presence of triple points in the phase diagram of the model with chemical-potential disorder. These triple points, however, cease to exist after the addition of the hopping disorder.

  9. The interplay of crack hopping, delamination and interface failure in drying nanoparticle films.

    PubMed

    Yang, Bin; Sharp, James S; Smith, Mike I

    2016-01-01

    Films formed through the drying of nanoparticle suspensions release the build-up of strain through a variety of different mechanisms including shear banding, crack formation and delamination. Here we show that important connections exist between these different phenomena: delamination depends on the dynamics of crack hopping, which in turn is influenced by the presence of shear bands. We also show that delamination does not occur uniformly across the film. As cracks hop they locally initiate the delamination of the film which warps with a timescale much longer than that associated with the hopping of cracks. The motion of a small region of the delamination front, where the shear component of interfacial crack propagation is believed to be enhanced, results in the deposition of a complex zig-zag pattern on the supporting substrate. PMID:27558989

  10. Colossal Seebeck Coefficient of Hopping Electrons in (TMTSF) 2 PF6

    NASA Astrophysics Data System (ADS)

    Machida, Yo; Lin, Xiao; Kang, Woun; Izawa, Koichi; Behnia, Kamran

    2016-02-01

    We report on a study of the Seebeck coefficient and resistivity in the quasi-one-dimensional conductor (TMTSF) 2 PF6 extended deep into the spin-density-wave state. The metal-insulator transition at TSDW=12 K leads to a reduction in carrier concentration by 7 orders of magnitude. Below 1 K, charge transport displays the behavior known as variable range hopping. Until now, the Seebeck response of electrons in this regime has barely been explored and is even less understood. We find that, in this system, residual carriers, hopping from one trap to another, generate a Seebeck coefficient as large as 400 kB/e . The results provide the first solid evidence for a long-standing prediction according to which hopping electrons in the presence of the Coulomb interaction can generate a sizable Seebeck coefficient in the zero-temperature limit.

  11. Hidden String Order in a Hole Superconductor with Extended Correlated Hopping

    NASA Astrophysics Data System (ADS)

    Chhajlany, Ravindra W.; Grzybowski, Przemysław R.; Stasińska, Julia; Lewenstein, Maciej; Dutta, Omjyoti

    2016-06-01

    Ultracold fermions in one-dimensional, spin-dependent nonoverlapping optical lattices are described by a nonstandard Hubbard model with next-nearest-neighbor correlated hopping. In the limit of a kinetically constraining value of the correlated hopping equal to the normal hopping, we map the invariant subspaces of the Hamiltonian exactly to free spinless fermion chains of varying lengths. As a result, the system exactly manifests spin-charge separation and we obtain the system properties for arbitrary filling: ground state collective order characterized by a spin gap, which can be ascribed to an unconventional critical hole superconductor associated with finite long range nonlocal string order. We study the system numerically away from the integrable point and show the persistence of both long range string order and spin gap for appropriate parameters as well as a transition to a ferromagnetic state.

  12. The interplay of crack hopping, delamination and interface failure in drying nanoparticle films

    PubMed Central

    Yang, Bin; Sharp, James S.; Smith, Mike I.

    2016-01-01

    Films formed through the drying of nanoparticle suspensions release the build-up of strain through a variety of different mechanisms including shear banding, crack formation and delamination. Here we show that important connections exist between these different phenomena: delamination depends on the dynamics of crack hopping, which in turn is influenced by the presence of shear bands. We also show that delamination does not occur uniformly across the film. As cracks hop they locally initiate the delamination of the film which warps with a timescale much longer than that associated with the hopping of cracks. The motion of a small region of the delamination front, where the shear component of interfacial crack propagation is believed to be enhanced, results in the deposition of a complex zig-zag pattern on the supporting substrate. PMID:27558989

  13. Surface hopping, transition state theory, and decoherence. II. Thermal rate constants and detailed balance

    SciTech Connect

    Jain, Amber; Subotnik, Joseph E.

    2015-10-07

    We investigate a simple approach to compute a non-adiabatic thermal rate constant using the fewest switches surface hopping (FSSH) dynamics. We study the effects of both decoherence (using our augmented-FSSH (A-FSSH) algorithm) and forbidden hops over a large range of parameters, including high and low friction regimes, and weak and strong electronic coupling regimes. Furthermore, when possible, we benchmark our results against exact hierarchy equations of motion results, where we usually find a maximum error of roughly a factor of two (at reasonably large temperatures). In agreement with Hammes-Schiffer and Tully, we find that a merger of transition state theory and surface hopping can be both accurate and efficient when performed correctly. We further show that detailed balance is followed approximately by A-FSSH dynamics.

  14. The influence of pruning and harvest timing on hop aroma, cone appearance, and yield.

    PubMed

    Matsui, Hiroo; Inui, Takako; Oka, Kaneo; Fukui, Nobuyuki

    2016-07-01

    Humulus lupulus (hop) cone is a key ingredient of beer, which determines its taste and aroma. Thus, it is necessary to control its cultivation conditions to acquire suitable quality. Here, cultivation conditions, such as pruning, blooming, and harvest timings, were modified for the Saaz hop variety in the Saaz region of Czech Republic. We investigated the correlation between the abovementioned cultivation factors and hop aroma characteristics, chemical components, appearance, yield, and beer quality in four locations and in three years. Harvest timing had a significant impact on the amount of essential oils, especially monoterpenes. Among them, linalool, geraniol and myrcene, which contribute beer hoppy aroma, increased with delay in harvest timing. These impacts caused by harvest timing were confirmed in all 4 locations and in all 3years. Our findings suggest that harvest timing influences the intensity and quality of beer hoppy aroma. PMID:26920261

  15. Effects of long-range hopping and interactions on quantum walks in ordered and disordered lattices

    NASA Astrophysics Data System (ADS)

    Chattaraj, T.; Krems, R. V.

    2016-08-01

    We study the effects of long-range hopping and long-range interparticle interactions on the quantum walk of hard-core bosons in ideal and disordered one-dimensional lattices. We find that the range of hopping has a much more significant effect on the particle correlation dynamics than the range of interactions. We illustrate that long-range hopping makes the correlation diagrams asymmetric with respect to the sign of the interaction. We examine the relative role of repulsive and attractive interactions on the dynamics of scattering by isolated impurities and Anderson localization in disordered lattices. We show that weakly repulsive interactions increase the probability of tunneling through isolated impurities and decrease the localization.

  16. Bridge-mediated hopping or superexchange electron-transfer processes in bis(triarylamine) systems

    NASA Astrophysics Data System (ADS)

    Lambert, Christoph; Nöll, Gilbert; Schelter, Jürgen

    2002-09-01

    Hopping and superexchange are generally considered to be alternative electron-transfer mechanisms in molecular systems. In this work we used mixed-valence radical cations as model systems for the investigation of electron-transfer pathways. We show that substituents attached to a conjugated bridge connecting two triarylamine redox centres have a marked influence on the near-infrared absorption spectra of the corresponding cations. Spectral analysis, followed by evaluation of the electron-transfer parameters using the Generalized Mulliken-Hush theory and simulation of the potential energy surfaces, indicate that hopping and superexchange are not alternatives, but are both present in the radical cation with a dimethoxybenzene bridge. We found that the type of electron-transfer mechanism depends on the bridge-reorganization energy as well as on the bridge-state energy. Because superexchange and hopping follow different distance laws, our findings have implications for the design of new molecular and polymeric electron-transfer materials.

  17. Fewest switches adiabatic surface hopping as applied to vibrational energy relaxation.

    PubMed

    Käb, Günter

    2006-03-01

    In this contribution quantum/classical surface hopping methodology is applied to vibrational energy relaxation of a quantum oscillator in a classical heat bath. The model of a linearly damped (harmonic) oscillator is chosen which can be mapped onto the Brownian motion (Caldeira-Leggett) Hamiltonian. In the simulations Tully's fewest switches surface hopping scheme is adopted with inclusion of dephasing in the adiabatic basis using a simple decoherence algorithm. The results are compared to the predictions of a Redfield-type quantum master equation modeling using the classical heat bath force correlation function as input. Thereby a link is established between both types of quantum/classical approaches. Viewed from the latter perspective, surface hopping with dephasing may be interpreted as "on-the-fly" stochastic realization of a quantum/classical Pauli master equation. PMID:16509644

  18. Mode-hopping mechanism generating colored noise in a magnetic tunnel junction based spin torque oscillator

    SciTech Connect

    Sharma, Raghav; Dürrenfeld, P.; Iacocca, E.; Heinonen, O. G.; Åkerman, J.; Muduli, P. K.

    2014-09-29

    The frequency noise spectrum of a magnetic tunnel junction based spin torque oscillator is examined where multiple modes and mode-hopping events are observed. The frequency noise spectrum is found to consist of both white noise and 1/f frequency noise. We find a systematic and similar dependence of both white noise and 1/f frequency noise on bias current and the relative angle between the reference and free layers, which changes the effective damping and hence the mode-hopping behavior in this system. The frequency at which the 1/f frequency noise changes to white noise increases as the free layer is aligned away from the anti-parallel orientation w.r.t the reference layer. These results indicate that the origin of 1/f frequency noise is related to mode-hopping, which produces both white noise as well as 1/f frequency noise similar to the case of ring lasers.

  19. Testing.

    ERIC Educational Resources Information Center

    Killoran, James, Ed.

    1984-01-01

    This journal issue addresses the issue of testing in the social studies classroom. The first article, "The Role of Testing" (Bragaw), focuses on the need for tests to reflect the objectives of the study completed. The varying functions of pop quizzes, weekly tests, and unit tests are explored. "Testing Thinking Processes" (Killoran, Zimmer, and…

  20. Decoding Hip-Hop's Cultural Impact: Scholars Are Poised to Take a Close Look at the Influence of Hip-Hop on the Social Identity, Values of Today's Youth

    ERIC Educational Resources Information Center

    Roach, Ronald

    2004-01-01

    As a cultural movement, hip-hop manages to get billed as both a positive and negative influence on young people, especially on Black and Latino youth. On one hand, there are African American activists, artists and entrepreneurs, such as Russell Simmons, who seek to build a progressive political movement among young hip-hop fans and who have had…

  1. Crystal structure of the effector protein HopA1 from Pseudomonas syringae.

    PubMed

    Park, Yangshin; Shin, Inchul; Rhee, Sangkee

    2015-03-01

    Plants have evolved to protect themselves against pathogen attack; in these competitions, many Gram-negative bacteria translocate pathogen-originated proteins known as effectors directly into plant cells to interfere with cellular processes. Effector-triggered immunity (ETI) is a plant defense mechanism in which plant resistance proteins recognize the presence of effectors and initiate immune responses. Enhanced disease susceptibility 1 (EDS1) in Arabidopsis thaliana serves as a central node protein for basal immune resistance and ETI by interacting dynamically with other immune regulatory or resistance proteins. Recently, the effector HopA1 from Pseudomonas syringae was shown to affect these EDS1 complexes by binding EDS1 directly and activating the immune response signaling pathway. Here, we report the crystal structure of the effector HopA1 from P. syringae pv. syringae strain 61 and tomato strain DC3000. HopA1, a sequence-unrelated protein to EDS1, has an α+β fold in which the central antiparallel β-sheet is flanked by helices. A similar structural domain, an α/β fold, is one of the two domains in both EDS1 and the EDS1-interacting protein SAG101, and plays a crucial role in forming the EDS1 complex. Further analyses suggest structural similarity and differences between HopA1 and the α/β fold of SAG101, as well as between two HopA1s from different pathovars. Our structural analysis provides a foundation for understanding the molecular basis of the effect of HopA1 on plant immunity. PMID:25681297

  2. The Draft Genome of Hop (Humulus lupulus), an Essence for Brewing.

    PubMed

    Natsume, Satoshi; Takagi, Hiroki; Shiraishi, Akira; Murata, Jun; Toyonaga, Hiromi; Patzak, Josef; Takagi, Motoshige; Yaegashi, Hiroki; Uemura, Aiko; Mitsuoka, Chikako; Yoshida, Kentaro; Krofta, Karel; Satake, Honoo; Terauchi, Ryohei; Ono, Eiichiro

    2015-03-01

    The female flower of hop (Humulus lupulus var. lupulus) is an essential ingredient that gives characteristic aroma, bitterness and durability/stability to beer. However, the molecular genetic basis for identifying DNA markers in hop for breeding and to study its domestication has been poorly established. Here, we provide draft genomes for two hop cultivars [cv. Saazer (SZ) and cv. Shinshu Wase (SW)] and a Japanese wild hop [H. lupulus var. cordifolius; also known as Karahanasou (KR)]. Sequencing and de novo assembly of genomic DNA from heterozygous SW plants generated scaffolds with a total size of 2.05 Gb, corresponding to approximately 80% of the estimated genome size of hop (2.57 Gb). The scaffolds contained 41,228 putative protein-encoding genes. The genome sequences for SZ and KR were constructed by aligning their short sequence reads to the SW reference genome and then replacing the nucleotides at single nucleotide polymorphism (SNP) sites. De novo RNA sequencing (RNA-Seq) analysis of SW revealed the developmental regulation of genes involved in specialized metabolic processes that impact taste and flavor in beer. Application of a novel bioinformatics tool, phylogenetic comparative RNA-Seq (PCP-Seq), which is based on read depth of genomic DNAs and RNAs, enabled the identification of genes related to the biosynthesis of aromas and flavors that are enriched in SW compared to KR. Our results not only suggest the significance of historical human selection process for enhancing aroma and bitterness biosyntheses in hop cultivars, but also serve as crucial information for breeding varieties with high quality and yield. PMID:25416290

  3. Asymmetric Exclusion Process with Constrained Hopping and Parallel Dynamics at a Junction

    NASA Astrophysics Data System (ADS)

    Liu, Mingzhe; Tuo, Xianguo; Li, Zhe; Yang, Jianbo

    In this article totally asymmetric simple exclusion process (TASEP) with constrained hopping and parallel dynamics at a junction is investigated using a mean-field approximation and Monte Carlo simulations. The constrained particle hopping probability r (r ≤ 1) at a junction may correspond to a delay caused by a driver choosing the right direction or a delay waiting for green traffic light in the real world. There are six stationary phases in the system, which can reflect free flow and congested traffic situations. Correlations at the junction point are investigated via simulations. It is observed that small r leads to stronger correlations. The theoretical results are agreement with computer simulations well.

  4. Competition between thermally activated and tip-induced hopping of indium atoms on Si(100)

    NASA Astrophysics Data System (ADS)

    Setvín, Martin; Javorský, Jakub; Majzik, Zsolt; Sobotík, Pavel; Kocán, Pavel; Ošt'Ádal, Ivan

    2012-02-01

    The adsorption and dynamics of single indium atoms on a Si(100) surface were studied by means of scanning tunneling microscopy in a temperature range from 30 to 130 K. Single In adatoms are strongly influenced by a tip-surface interaction which is proportional to the tunneling current. The surface hopping of the In adatoms was recorded and conditions minimizing the tip-surface interaction were investigated. The activation energies and frequency prefactors for thermally activated hopping were calculated from a temperature dependence of lifetimes of In adatoms in adsorption positions.

  5. Combined hopping?superexchange model of a hole transfer in DNA

    NASA Astrophysics Data System (ADS)

    Lakhno, V. D.; Sultanov, V. B.; Pettitt, B. Montgomery

    2004-12-01

    Relative hole transfer rates in DNA have been investigated in a number of nucleotide sequences experimentally. Calculation of the transfer rates in DNA is performed relying on the assumption that the transfer is realized as hopping of a hole on guanine sites, each hop being calculated on the basis of superexchange theory. It is shown that the medium reorganization energy and free energy changes play an important role in determining the transfer rate and the type of a nucleotide sequence. The results of the calculations are compared with experimental data covering a range of available sequences.

  6. Numerical studies of variable-range hopping in one-dimensional systems

    NASA Astrophysics Data System (ADS)

    Rodin, A. S.; Fogler, M. M.

    2010-03-01

    We report on our recent numerical study [1] of hopping transport in disordered one-dimensional systems. A fast new algorithm, based on Dijkstra shortest-path algorithm, is devised to find the lowest-resistance path through the hopping network at arbitrary electric field. Probability distribution functions of individual resistances on the path and the net resistance are calculated and fitted to compact analytic formulas. Qualitative differences between statistics of resistance fluctuations in Ohmic and non-Ohmic regimes are elucidated. The results are compared with prior theoretical and experimental work on the subject.[6pt] [1] A. S. Rodin and M. M. Fogler, Phys. Rev. B 80, 155435 (2009).

  7. Effects of xanthohumol-rich hop extract on the differentiation of preadipocytes.

    PubMed

    Kiyofuji, Ayane; Yui, Kazuki; Takahashi, Koki; Osada, Kyoichi

    2014-01-01

    Xanthohumol is a major prenylated, hydrophobic flavonoid found in the female inflorescences of the hop plant (Humulus lupulus L.). In this study, we examined the effects of xanthohumol-rich hop extract containing 17.8% xanthohumol and 12.4% isoxanthohumol on the differentiation and adipogenesis of 3T3L1 cells. We observed that the extract inhibited the differentiation of 3T3L1 cells and intracellular fat droplets via the regulation of adipogenic factors such as the peroxisome proliferator-activated receptor gamma, CCAAT/enhancer binding protein alpha, and adipocyte fatty acid-binding protein. PMID:24829131

  8. In and out of love with hip-hop: saliency of sexual scripts for young adult African American women in hip-hop and Black-oriented television.

    PubMed

    Coleman, M Nicole; Butler, Ebony O; Long, Amanda M; Fisher, Felicia D

    2016-10-01

    Hip-hop media and Black-oriented reality television are powerful mechanisms for conveying and promoting stereotypes of Black women. Black women's sexuality is frequently presented as highly-salient in each medium. However, little is known about the impact of those images on Black women's sexuality and identity. The current study uses focus-group methodology to engage young adult Black in critical discussion of two predominant sexual scripts found in hip-hop music and Black-oriented reality television - the Freak and the Gold Digger. Analyses revealed shared and distinct aspects of each sexual script represented in both media and the impact of those scripts on participants' experiences. Implications for future research are discussed. PMID:27188876

  9. The Habc Domain of the SNARE Vam3 Interacts with the HOPS Tethering Complex to Facilitate Vacuole Fusion*

    PubMed Central

    Lürick, Anna; Kuhlee, Anne; Bröcker, Cornelia; Kümmel, Daniel; Raunser, Stefan; Ungermann, Christian

    2015-01-01

    Membrane fusion at vacuoles requires a consecutive action of the HOPS tethering complex, which is recruited by the Rab GTPase Ypt7, and vacuolar SNAREs to drive membrane fusion. It is assumed that the Sec1/Munc18-like Vps33 within the HOPS complex is largely responsible for SNARE chaperoning. Here, we present direct evidence for HOPS binding to SNAREs and the Habc domain of the Vam3 SNARE protein, which may explain its function during fusion. We show that HOPS interacts strongly with the Vam3 Habc domain, assembled Q-SNAREs, and the R-SNARE Ykt6, but not the Q-SNARE Vti1 or the Vam3 SNARE domain. Electron microscopy combined with Nanogold labeling reveals that the binding sites for vacuolar SNAREs and the Habc domain are located in the large head of the HOPS complex, where Vps16 and Vps33 have been identified before. Competition experiments suggest that HOPS bound to the Habc domain can still interact with assembled Q-SNAREs, whereas Q-SNARE binding prevents recognition of the Habc domain. In agreement, membranes carrying Vam3ΔHabc fuse poorly unless an excess of HOPS is provided. These data suggest that the Habc domain of Vam3 facilitates the assembly of the HOPS/SNARE machinery at fusion sites and thus supports efficient membrane fusion. PMID:25564619

  10. The Tale of the Talent Night Rap: Hip-Hop Culture in Schools and the Challenge of Interpretation

    ERIC Educational Resources Information Center

    Low, Bronwen E.

    2010-01-01

    Although the number of calls to integrate Hip-Hop culture into school curricula is growing, little attention is being paid to the reluctance of teachers and administrators to forge relationships between the cultures of school and of youth. This article explores some of the difficulties inherent in the relationships between Hip Hop and schooling,…

  11. "You Don't Have to Claim Her": Reconstructing Black Femininity through Critical Hip-Hop Literacy

    ERIC Educational Resources Information Center

    Kelly, Lauren Leigh

    2016-01-01

    This article explores the ways in which females who identify with hip-hop often develop and construct their identities in relation to media representations of blackness and femininity in hip-hop music and culture. In order for educators to support female students in constructing identities of empowerment and agency, they should be willing and able…

  12. Fresh Faces, New Places: Moving beyond Teacher-Researcher Perspectives in Hip-Hop-Based Education Research

    ERIC Educational Resources Information Center

    Irby, Decoteau J.; Hall, H. Bernard

    2011-01-01

    Grounded in critical and culturally relevant theory, hip-hop-based education (HHBE) research documents the use of hip-hop in educational settings. Despite the richness of the emerging field, overreliance on teacher-researcher perspectives leaves much to be desired. Little is known of the extent and ways HHBE is used by nonresearching K-12…

  13. Dialoguing, Cultural Capital, and Student Engagement: Toward a Hip Hop Pedagogy in the High School and University Classroom

    ERIC Educational Resources Information Center

    Rodriguez, Louie F.

    2009-01-01

    Hip hop culture is typically excluded from conventional educational spaces within the U.S. Drawing on the experiences of an educator who works with urban high school students and university level pre- and in-service educators, this article examines the role of hip hop culture for student engagement in two settings--an alternative high school…

  14. "Dear Tupac, You Speak to Me": Recruiting Hip Hop as Curriculum at a School for Pregnant and Parenting Teens

    ERIC Educational Resources Information Center

    Hallman, Heidi L.

    2009-01-01

    This article provides a rich representation of how in-school practices that recruit students' "out-of-school" literacies, such as hip hop, can be used as critical bridges in students' learning. Hip hop, conceptualized in this article as an "out-of-school" literacy, works as a vehicle for curricular change at Eastview School for Pregnant and…

  15. Development of biological control of Tetranychus urticae (Acari:Tetranychidae) and Phorodon humuli (Hemiptera: Aphididae) in Oregon Hop yards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The temporal development of biological control of arthropod pests in perennial cropping systems is largely unreported. In this study, the development of biological control of twospotted spider mite, Tetranychus urticae Koch and hop aphid, Phorodon humuli (Schrank) in a new planting of hop in Oregon...

  16. Culturally Relevant Teaching: Hip-Hop Pedagogy in Urban Schools. Counterpoints: Studies in the Postmodern Theory of Education. Volume 396

    ERIC Educational Resources Information Center

    Prier, Darius D.

    2012-01-01

    "Culturally Relevant Teaching" centers hip-hop culture as a culturally relevant form of critical pedagogy in urban pre-service teacher education programs. In this important book, Darius D. Prier explores how hip-hop artists construct a sense of democratic education and pedagogy with transformative possibilities in their schools and communities. In…

  17. Recruitment of VPS33A to HOPS by VPS16 Is Required for Lysosome Fusion with Endosomes and Autophagosomes

    PubMed Central

    Wartosch, Lena; Günesdogan, Ufuk; Graham, Stephen C; Luzio, J Paul

    2015-01-01

    The mammalian homotypic fusion and vacuole protein sorting (HOPS) complex is comprised of six subunits: VPS11, VPS16, VPS18, VPS39, VPS41 and the Sec1/Munc18 (SM) family member VPS33A. Human HOPS has been predicted to be a tethering complex required for fusion of intracellular compartments with lysosomes, but it remains unclear whether all HOPS subunits are required. We showed that the whole HOPS complex is required for fusion of endosomes with lysosomes by monitoring the delivery of endocytosed fluorescent dextran to lysosomes in cells depleted of individual HOPS proteins. We used the crystal structure of the VPS16/VPS33A complex to design VPS16 and VPS33A mutants that no longer bind each other and showed that, unlike the wild-type proteins, these mutants no longer rescue lysosome fusion with endosomes or autophagosomes in cells depleted of the endogenous proteins. There was no effect of depleting either VIPAR or VPS33B, paralogs of VPS16 and VPS33A, on fusion of lysosomes with either endosomes or autophagosomes and immunoprecipitation showed that they form a complex distinct from HOPS. Our data demonstrate the necessity of recruiting the SM protein VPS33A to HOPS via its interaction with VPS16 and that HOPS proteins, but not VIPAR or VPS33B, are essential for fusion of endosomes or autophagosomes with lysosomes. PMID:25783203

  18. Hip-Hop Feminism: A Standpoint to Enhance the Positive Self-Identity of Black College Women

    ERIC Educational Resources Information Center

    Henry, Wilma J.

    2010-01-01

    The popularity of hip-hop among young Black college women, coupled with the deluge of negative and positive messages in this culture regarding these women's identity, signals an opportunity for the arrival of a contemporary, culturally relevant epistemology--hip-hop feminism. Through the lens of Black feminist theory, this article explores hip-hop…

  19. An Educational Exploration of Homophobia and Sexism in Rap and Hip Hop: Homo-Thugs and Divas in da House

    ERIC Educational Resources Information Center

    Chiu, Nicholas

    2005-01-01

    In this paper, the author explores the connections between hip hop and rap, sexism and homophobia, and children and teens. He describes the implications or potential consequences of sexism and homophobia within the music and media culture of hip hop and rap (with the focus on how it affects young viewers and fans in terms of gender [identity]…

  20. Hop/STI1 modulates retinal proliferation and cell death independent of PrP{sup C}

    SciTech Connect

    Arruda-Carvalho, Maithe; Njaine, Brian; Silveira, Mariana S.; Linden, Rafael; Chiarini, Luciana B. . E-mail: chiarini@biof.ufrj.br

    2007-09-21

    Hop/STI1 is a co-chaperone adaptor protein for Hsp70/Hsp90 complexes. Hop/STI1 is found extracellularly and modulates cell death and differentiation through interaction with the prion protein (PrP{sup C}). Here, we investigated the expression of hop/STI1 and its role upon cell proliferation and cell death in the developing retina. Hop/STI1 is more expressed in developing rat retina than in the mature tissue. Hop/STI1 blocks retinal cell death in the neuroblastic layer (NBL) in a PrP{sup C} dependent manner, but failed to protect ganglion cells against axotomy-induced cell death. An antibody raised against hop/STI1 ({alpha}-STI1) blocked both ganglion cell and NBL cell death independent of PrP{sup C}. cAMP/PKA, ERK, PI3K and PKC signaling pathways were not involved in these effects. Hop/STI1 treatment reduced proliferation, while {alpha}-STI1 increased proliferation in the developing retina, both independent of PrP{sup C}. We conclude that hop/STI1 can modulate both proliferation and cell death in the developing retina independent of PrP{sup C}.

  1. Sclerotinia wilt of Hop (Humulus lupulus) caused by Sclerotinia sclerotiorum in the Pacific Northwest U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum is a widespread, destructive pathogen with an exceptionally broad host range. During June 2011, wilted hop plants (Humulus lupulus cv. Nugget) were observed in a hop yard in Marion County, Oregon. Some affected plants had upward curled leaves with necrotic margins, whereas o...

  2. Involvement of Vacuolar Sequestration and Active Transport in Tolerance of Saccharomyces cerevisiae to Hop Iso-α-Acids▿ † ¶

    PubMed Central

    Hazelwood, Lucie A.; Walsh, Michael C.; Pronk, Jack T.; Daran, Jean-Marc

    2010-01-01

    The hop plant, Humulus lupulus L., has an exceptionally high content of secondary metabolites, the hop α-acids, which possess a range of beneficial properties, including antiseptic action. Studies performed on the mode of action of hop iso-α-acids have hitherto been restricted to lactic acid bacteria. The present study investigated molecular mechanisms of hop iso-α-acid resistance in the model eukaryote Saccharomyces cerevisiae. Growth inhibition occurred at concentrations of hop iso-α-acids that were an order of magnitude higher than those found with hop-tolerant prokaryotes. Chemostat-based transcriptome analysis and phenotype screening of the S. cerevisiae haploid gene deletion collection were used as complementary methods to screen for genes involved in hop iso-α-acid detoxification and tolerance. This screening and further analysis of deletion mutants confirmed that yeast tolerance to hop iso-α-acids involves three major processes, active proton pumping into the vacuole by the vacuolar-type ATPase to enable vacuolar sequestration of iso-α-acids and alteration of cell wall structure and, to a lesser extent, active export of iso-α-acids across the plasma membrane. Furthermore, iso-α-acids were shown to affect cellular metal homeostasis by acting as strong zinc and iron chelators. PMID:19915041

  3. I Feel What He Was Doin': Responding to Justice-Oriented Teaching through Hip-Hop Aesthetics

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2011-01-01

    This study illustrates a set of learning activities designed from two hip-hop aesthetics and explores their use among a classroom of African American preservice teachers who graduated from urban school districts. Based on the two hip-hop aesthetics of kinetic consumption and autonomy/distance, the specific goal of these learning activities is to…

  4. Enhanced multi-hop operation using hybrid optoelectronic router with time-to-live-based selective forward error correction.

    PubMed

    Nakahara, Tatsushi; Suzaki, Yasumasa; Urata, Ryohei; Segawa, Toru; Ishikawa, Hiroshi; Takahashi, Ryo

    2011-12-12

    Multi-hop operation is demonstrated with a prototype hybrid optoelectronic router for optical packet switched networks. The router is realized by combining key optical/optoelectronic device/sub-system technologies and complementary metal-oxide-semiconductor electronics. Using the hop count monitored via the time-to-live field in the packet label, the optoelectronic buffer of the router performs buffering with forward error correction selectively for packets degraded due to multiple hopping every N hops. Experimental results for 10-Gb/s optical packets confirm that the scheme can expand the number of hops while keeping the bit error rate low without the need for optical 3R regenerators at each node. PMID:22274034

  5. Surface hopping outperforms secular Redfield theory when reorganization energies range from small to moderate (and nuclei are classical)

    SciTech Connect

    Landry, Brian R. Subotnik, Joseph E.

    2015-03-14

    We evaluate the accuracy of Tully’s surface hopping algorithm for the spin-boson model in the limit of small to moderate reorganization energy. We calculate transition rates between diabatic surfaces in the exciton basis and compare against exact results from the hierarchical equations of motion; we also compare against approximate rates from the secular Redfield equation and Ehrenfest dynamics. We show that decoherence-corrected surface hopping performs very well in this regime, agreeing with secular Redfield theory for very weak system-bath coupling and outperforming secular Redfield theory for moderate system-bath coupling. Surface hopping can also be extended beyond the Markovian limits of standard Redfield theory. Given previous work [B. R. Landry and J. E. Subotnik, J. Chem. Phys. 137, 22A513 (2012)] that establishes the accuracy of decoherence-corrected surface-hopping in the Marcus regime, this work suggests that surface hopping may well have a very wide range of applicability.

  6. New implementation of the trajectory surface hopping method with use of the Zhu-Nakamura theory. II. Application to the charge transfer processes in the 3D DH2+ system

    NASA Astrophysics Data System (ADS)

    Zhu, Chaoyuan; Kamisaka, Hideyuki; Nakamura, Hiroki

    2002-02-01

    The newly implemented trajectory surface hopping (TSH) method for the collinear system with use of the Zhu-Nakamura semiclassical theory of nonadiabatic transition [C. Zhu, K. Nobusada, and H. Nakamura, J. Chem. Phys. 115, 3031 (2001)] is extended to treat 3D nonadiabatic reactions. Since the avoided crossing seam becomes a two-dimensional surface in the 3D system, the nonadiabatic transition region and the possibility of classically forbidden hops are enlarged very much in comparison with those in the collinear case. As a result, the contribution of the classically forbidden hops is quite a bit enhanced in the 3D system. Conservation of total angular momentum J is taken into account by slightly rotating the direction of momentum during the hop in the classically forbidden case. The method is tested by applying to the charge transfer processes in the 3D DH2+ system for J=0. Numerical results clearly demonstrate that the new TSH method works very well at all energies and for all initial vibrational states considered compared to the old TSH method based on the Landau-Zener formula. The significant discrepancy between the two TSH methods survives even at high collision energy and high vibrational states in contrast to the collinear case, indicating the importance of the classically forbidden hops in 3D systems. The new TSH method is considered to be a very promising method to deal with high dimensional nonadiabatic dynamics. It should also be noted that the new TSH method does not require any knowledge of nonadiabatic coupling and is based only on adiabatic potentials.

  7. Hip-Hop--What's in It for the Academy? Self-Understanding, Pedagogy and Aesthetical Learning Processes in Everyday Cultural Praxis

    ERIC Educational Resources Information Center

    Söderman, Johan; Sernhede, Ove

    2016-01-01

    Since hip-hop first appeared in New York over 35 years ago, it has been associated with social activism and education. Accordingly, it is not surprising that academic institutions in universities and K-12 schools are interested in hip-hop. In this article, we will highlight the "hip-hop academisation" and map out a new direction in a…

  8. Youth Perspectives on the Intersections of Violence, Gender, and Hip-Hop

    ERIC Educational Resources Information Center

    Hernandez, Diana; Weinstein, Hannah; Munoz-Laboy, Miguel

    2012-01-01

    Youth's perceptions of violence within their social environments can provide relevant insights into the gender-based interpersonal violence epidemic in inner-city communities. To explore this issue, we examined two sets of narratives with young men and women, aged 15 to 21, involved in hip-hop culture in New York City. In the analysis, we reveal…

  9. Development of partial ontogenic resistance to powdery mildew in Hop cones and its management implications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of processes leading to crop damage is central to devising rational approaches to disease management. Multiple experiments established that infection of hop cones by Podosphaera macularis was most severe if inoculation occurred within 15 to 21 days after bloom. This period of infection was...

  10. 75 FR 70236 - Hop Beta Acids; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-17

    ... treat up to 181,000 honey bee colonies in the Pacific North West (PNW) to control varroa mites. The... exemption regional request for use of hop beta acids in honey bee hives to control varroa mites. Information... effect on honey bee populations. The parasitic mite is considered the primary pest of honeybees and...

  11. Sampling Memories: Using Hip-Hop Aesthetics to Learn from Urban Schooling Experiences

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2012-01-01

    This article theorizes and charts the implementation of a learning activity designed from the hip-hop aesthetic of sampling. The purpose of this learning activity was to enable recent urban school graduates to reflect upon their previous schooling experiences as a platform for future learning in higher education. This article illustrates what…

  12. Use of the Homeland-Defense Operational Planning System (HOPS) for Emergency Management

    SciTech Connect

    Durling, Jr., R L; Price, D E

    2005-12-16

    The Homeland-Defense Operational Planning System (HOPS), is a new operational planning tool leveraging Lawrence Livermore National Laboratory's expertise in weapons systems and in sparse information analysis to support the defense of the U.S. homeland. HOPS provides planners with a basis to make decisions to protect against acts of terrorism, focusing on the defense of facilities critical to U.S. infrastructure. Criticality of facilities, structures, and systems is evaluated on a composite matrix of specific projected casualty, economic, and sociopolitical impact bins. Based on these criteria, significant unidentified vulnerabilities are identified and secured. To provide insight into potential successes by malevolent actors, HOPS analysts strive to base their efforts mainly on unclassified open-source data. However, more cooperation is needed between HOPS analysts and facility representatives to provide an advantage to those whose task is to defend these facilities. Evaluated facilities include: refineries, major ports, nuclear power plants and other nuclear licensees, dams, government installations, convention centers, sports stadiums, tourist venues, and public and freight transportation systems. A generalized summary of analyses of U.S. infrastructure facilities will be presented.

  13. Risk Assessment Using The Homeland-Defense Operational Planning System (HOPS)

    SciTech Connect

    Price, D E; Durling, R L

    2005-10-10

    The Homeland-Defense Operational Planning System (HOPS), is a new operational planning tool leveraging Lawrence Livermore National Laboratory's expertise in weapons systems and in sparse information analysis to support the defense of the U.S. homeland. HOPS provides planners with a basis to make decisions to protect against acts of terrorism, focusing on the defense of facilities critical to U.S. infrastructure. Criticality of facilities, structures, and systems is evaluated on a composite matrix of specific projected casualty, economic, and sociopolitical impact bins. Based on these criteria, significant unidentified vulnerabilities are identified and secured. To provide insight into potential successes by malevolent actors, HOPS analysts strive to base their efforts mainly on unclassified open-source data. However, more cooperation is needed between HOPS analysts and facility representatives to provide an advantage to those whose task is to defend these facilities. Evaluated facilities include: refineries, major ports, nuclear power plants and other nuclear licensees, dams, government installations, convention centers, sports stadiums, tourist venues, and public and freight transportation systems. A generalized summary of analyses of U.S. infrastructure facilities will be presented.

  14. Vulnerability And Risk Assessment Using The Homeland-Defense Operational Planning System (HOPS)

    SciTech Connect

    Durling, Jr., R L; Price, D E; Spero, K K

    2005-01-03

    For over ten years, the Counterproliferation Analysis and Planning System (CAPS) at Lawrence Livermore National Laboratory (LLNL) has been a planning tool used by U.S. combatant commands for mission support planning against foreign programs engaged in the manufacture of weapons of mass destruction (WMD). CAPS is endorsed by the Secretary of Defense as the preferred counterproliferation tool to be used by the nation's armed services. A sister system, the Homeland-Defense Operational Planning System (HOPS), is a new operational planning tool leveraging CAPS expertise designed to support the defense of the U.S. homeland. HOPS provides planners with a basis to make decisions to protect against acts of terrorism, focusing on the defense of facilities critical to U.S. infrastructure. Criticality of facilities, structures, and systems is evaluated on a composite matrix of specific projected casualty, economic, and sociopolitical impact bins. Based on these criteria, significant unidentified vulnerabilities are identified and secured. To provide insight into potential successes by malevolent actors, HOPS analysts strive to base their efforts mainly on unclassified open-source data. However, more cooperation is needed between HOPS analysts and facility representatives to provide an advantage to those whose task is to defend these facilities. Evaluated facilities include: refineries, major ports, nuclear power plants and other nuclear licensees, dams, government installations, convention centers, sports stadiums, tourist venues, and public and freight transportation systems. A generalized summary of analyses of U.S. infrastructure facilities is presented.

  15. Risk Assessment Using The Homeland-Defense Operational Planning System (HOPS)

    SciTech Connect

    Durling, R L; Price, D E; Spero, K K

    2005-06-06

    For over ten years, the Counterproliferation Analysis and Planning System (CAPS) at Lawrence Livermore National Laboratory (LLNL) has been a planning tool used by U.S. combatant commands for mission support planning against foreign programs engaged in the manufacture of weapons of mass destruction (WMD). CAPS is endorsed by the Secretary of Defense as the preferred counterproliferation tool to be used by the nation's armed services. A sister system, the Homeland-Defense Operational Planning System (HOPS), is a new operational planning tool leveraging CAPS expertise designed to support the defense of the U.S. homeland. HOPS provides planners with a basis to make decisions to protect against acts of terrorism, focusing on the defense of facilities critical to U.S. infrastructure. Criticality of facilities, structures, and systems is evaluated on a composite matrix of specific projected casualty, economic, and sociopolitical impact bins. Based on these criteria, significant unidentified vulnerabilities are identified and secured. To provide insight into potential successes by malevolent actors, HOPS analysts strive to base their efforts mainly on unclassified open-source data. However, more cooperation is needed between HOPS analysts and facility representatives to provide an advantage to those whose task is to defend these facilities. Evaluated facilities include: refineries, major ports, nuclear power plants and other nuclear licensees, dams, government installations, convention centers, sports stadiums, tourist venues, and public and freight transportation systems. A generalized summary of analyses of U.S. infrastructure facilities will be presented.

  16. High-Speed Hopping: Time-Resolved Tomographic PIV Measurements of Water Flea Swimming

    NASA Astrophysics Data System (ADS)

    Murphy, D. W.; Webster, D. R.; Yen, J.

    2012-11-01

    Daphniids, also known as water fleas, are small, freshwater crustaceans that live in a low-to-intermediate Reynolds number regime. These plankters are equipped with a pair of branched, setae-bearing antennae that they beat to impulsively propel themselves, or ``hop,'' through the water. A typical hop carries the daphniid one body length forward and is followed by a period of sinking. We present time-resolved tomographic PIV measurements of swimming by Daphnia magna. The body kinematics and flow physics of the daphniid hop are quantified. It is shown that the flow generated by each stroking antenna resembles an asymmetric viscous vortex ring. It is proposed that the flow produced by the daphniid hop can be modeled as a double Stokeslet consisting of two impulsively applied point forces separated by the animal width. The flow physics are discussed in the context of other species operating in the same Reynolds number range of 10 to 100: sea butterfly swimming and flight by the smallest flying insects.

  17. Characterization of the Migration of Hop Volatiles into Different Crown Cork Liner Polymers and Can Coatings.

    PubMed

    Wietstock, Philip C; Glattfelder, Richard; Garbe, Leif-Alexander; Methner, Frank-Jürgen

    2016-04-01

    Absorption of hop volatiles by crown cork liner polymers and can coatings was investigated in beer during storage. All hop volatiles measured were prone to migrate into the closures, and the absorption kinetics was demonstrated to fit Fick's second law of diffusion well for a plane sheet. The extent and rate of diffusion were significantly dissimilar and were greatly dependent upon the nature of the volatile. Diffusion coefficients ranged from 1.32 × 10(-5) cm(2)/day (limonene) to 0.26 × 10(-5) cm(2)/day (α-humulene). The maximum amounts absorbed into the material at equilibrium were in the following order: limonene > α-humulene > trans-caryophyllene > myrcene ≫ linalool > α-terpineol > geraniol. With the application of low-density polyethylene (LDPE) liners with oxygen-scavenging functionality, oxygen-barrier liners made up from high-density polyethylene (HDPE) or liner polymers from a different manufacturer had no significant effect on the composition of hop volatiles in beers after prolonged storage of 55 days; however, significantly higher amounts of myrcene and limonene were found in the oxygen-barrier-type crown cork, while all other closures behaved similarly. Can coatings were demonstrated to absorb hop volatiles in a similar pattern as crown corks but to a lesser extent. Consequently, significantly higher percentages of myrcene were found in the beers. PMID:26996287

  18. Medical-School Curriculum Goes Interactive, Online, ... and Hip-Hop

    ERIC Educational Resources Information Center

    Mangan, Katherine

    2008-01-01

    This article reports that Canadian medical students, inspired by an online community and an obscure heart condition, have ditched their books and transformed their class notes into a pulsating, hip-hop music video. "Diagnosis Wenckebach"--the name comes from a type of abnormal heart rhythm--was created as just one of many innovative study tools by…

  19. Media/Visual Literacy Art Education: Sexism in Hip-Hop Music Videos

    ERIC Educational Resources Information Center

    Chung, Sheng Kuan

    2007-01-01

    Media programs like hip-hop music videos are powerful aesthetic agents that inspire teenagers. Thus, they have tremendous influence on young people's identity formation, lifestyle choices, and knowledge construction which are manifested in the ways teens dress, express themselves, behave, and interact with each other. However, because of the…

  20. Peers as Teachers in Physical Education Hip Hop Classes in Finnish High School

    ERIC Educational Resources Information Center

    Nurmi, Anna-Maria; Kokkonen, Marja

    2015-01-01

    In this case study, theoretically rooted in peer-assisted learning (PAL), ten female high school students, acting as peer teachers, taught hip hop dance in a voluntary physical education course. The data, derived from questionnaires and interviews with the peer teachers, were analysed using content analysis. The results showed that the peer…

  1. Pedagogical Ideas on Sonic, Mediated, and Virtual Musical Landscapes: Teaching Hip Hop in a University Classroom

    ERIC Educational Resources Information Center

    Dhokai, Niyati

    2012-01-01

    Based on the experience of teaching the history of American hip hop music to a classroom of Canadian university students, the author considers the disjuncture between the cultural orientations of herself and her students. The author considers teaching methods to solve the place-based disjuncture that often occurs when teaching genres such as hip…

  2. Learning Processes and Social Mobilization in a Swedish Metropolitan Hip-Hop Collective

    ERIC Educational Resources Information Center

    Beach, Dennis; Sernhede, Ove

    2012-01-01

    Based on ethnographic research on the encounter between local culture and schools in multicultural suburban areas, this article explores possibilities suggested by autonomous learning activities in a hip-hop collective that may have a potential to break urban segregation patterns. The collective's artistic production raises questions that have not…

  3. Hip-Hop, Digital Media, and the Changing Face of Music Education

    ERIC Educational Resources Information Center

    Thibeault, Matthew D.

    2010-01-01

    In this article, the author describes a true story about Dwayne Carter Jr., a rapper most music educators probably don't know but one who is beloved throughout the world as "Lil Wayne." Critics overwhelmingly proclaimed Lil Wayne the top rapper in the hip-hop game, and the album and his work leading up to it were universally regarded as some of…

  4. Word Up: Using Spoken Word and Hip Hop Subject Matter in Pre-College Writing Instruction.

    ERIC Educational Resources Information Center

    Sirc, Geoffrey; Sutton, Terri

    2009-01-01

    In June 2008, the Department of English at the University of Minnesota partnered with the Minnesota Spoken Word Association to inaugurate an outreach literacy program for local high-school students and teachers. The four-day institute, named "In Da Tradition," used spoken word and hip hop to teach academic and creative writing to core-city…

  5. "Folkbildning" through Hip-Hop: How the Ideals of Three Rappers Parallel a Scandinavian Educational Tradition

    ERIC Educational Resources Information Center

    Soderman, Johan

    2011-01-01

    The purpose of this article is to show how the rappers' talk about hip-hop and its connection to pedagogy and social activism parallel the Scandinavian tradition of folkbildning. Scandinavian folkbildning can be seen as a movement to provide voluntary education for the general population. It can also be the name of the process of learning in which…

  6. From Haydn to Hip-Hop: Meeting Students' Needs in an Urban Classroom

    ERIC Educational Resources Information Center

    Vagi, Robert

    2010-01-01

    When an inner-city Arizona music teacher found himself faced with too many orchestra students and not enough instruments, he took a risky but rewarding left turn--into rap music. In this article, the author describes how he teaches his hip-hop class, the challenges in creating and teaching the class, and the positive results. (Contains 21…

  7. Critical Multimodal Hip Hop Production: A Social Justice Approach to African American Language and Literacy Practices

    ERIC Educational Resources Information Center

    Turner, K. C. Nat; Hayes, Nini, Visaya; Way, Kate

    2013-01-01

    This article features key findings from a study that highlights the transformative impact of a pedagogical approach that employs Critical Multimodal Hip Hop Production (CMHHP). The study took place in an extended day program in a northern California public middle school among a group of 30, urban, African American, Chicano/a/Latino/a, and Asian…

  8. High-throughput genotyping of hop (Humulus lupulus L.) utilising diversity arrays technology (DArT)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Implementation of molecular methods in hop breeding is dependent on the availability of sizeable numbers of polymorphic markers and a comprehensive understanding of genetic variation. Diversity Arrays Technology (DArT) is a high-throughput cost-effective method for the discovery of large numbers of...

  9. "Writing in the Margins": Brazilian Hip-Hop as an Educational Project

    ERIC Educational Resources Information Center

    Pardue, Derek

    2004-01-01

    Hip-hop culture's force as part of globalization in the fields of economics, popular aesthetics, and identity politics has been well documented. However, its articulation to educational practices has received less attention. This article draws upon fieldwork conducted in 1999 and 2002 in a youth correctional facility to analyze how state…

  10. Immunomodulation by the Pseudomonas syringae HopZ Type III Effector Family in Aribidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas syringae employs a type III secretion system to inject 20-30 different type III effector (T3SE) proteins into plant host cells. A major role of T3SEs is to suppress plant immune responses and promote bacterial infection. The YopJ/HopZ acetyltransferases are a superfamily of T3SEs found i...

  11. QTL Mapping of Powdery Mildew Susceptibility in Hop (Humulus lupulus L)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop powdery mildew is best controlled via the production of resistant varieties. Recent evidence supports selection for absence of susceptibility to fungal pathogens as a more durable resistance mechanism. The objective of this study was to identify molecular markers associated with susceptibility...

  12. Global Ill-Literacies: Hip Hop Cultures, Youth Identities, and the Politics of Literacy

    ERIC Educational Resources Information Center

    Alim, H. Samy

    2011-01-01

    This article focuses on the emergence of what the author refers to as "global ill-literacies," that is, the hybrid, transcultural linguistic and literacy practices of Hip Hop youth in local and global contexts, as well as the pedagogical possibilities that scholars open up as they engage these forms. By reviewing a broad but focused range of…

  13. Pistachio (Pistacia vera L.) is a new natural host of Hop stunt viroid.

    PubMed

    Elleuch, Amine; Hamdi, Imen; Ellouze, Olfa; Ghrab, Mohamed; Fkahfakh, Hatem; Drira, Noureddine

    2013-10-01

    Besides hop, Hop stunt viroid (HpSVd) infects many woody species including grapevine, citrus, peach, plum, apricot, almond, pomegranate, mulberry and jujube. Here, we report the first detection of HpSVd in pistachio (Pistacia vera L.). Samples corresponding to 16 pistachio cultivars were obtained from a nearby almond collection. From these samples, low molecular weight RNAs were extracted for double polyacrylamide gel electrophoresis, northern-blot analysis and reverse transcription polymerase chain reaction assays. HpSVd was detected in 4 of the 16 pistachio cultivars in the first year and in 6 in the second, being also detected in the almond collection. Examination of the nucleotide sequences of pistachio and almond isolates revealed 13 new sequence variants. Sequences from pistachio shared 92-96 % similarity with the first reported HpSVd sequence (GenBank X00009), and multiple alignment and phylogenetic analyses showed that one pistachio isolate (HpSVdPis67Jabari) clustered with the plum group, whereas all the others clustered with the hop, and the recombinants plum-citrus and plum-Hop/cit3 groups. By identifying pistachio as a new natural host, we confirm that HpSVd is an ubiquitous and genetically variable viroid that infects many different fruit trees cultivated worldwide. PMID:23775756

  14. Edge states in a honeycomb lattice: effects of anisotropic hopping and mixed edges

    SciTech Connect

    Dahal, Hari P; Balatsky, Alexander V; Sinistsyn, N A; Hu, Zi - Xiang; Yang, Kun

    2008-01-01

    We study the edge states in graphene in the presence of a magnetic field perpendicular to the plane of the lattice. Most of the work done so far discusses the edge states in either zigzag or armchair edge graphene considering an isotropic electron hopping. In practice, graphene can have a mixture of armchair and zigzag edges and the electron hopping can be anisotropic, which is the subject of this article. We predict that the mixed edges smear the enhanced local density of states (LDOS) at E=0 of the zigzag edge and, on the other hand, the anisotropic hopping gives rise to the enhanced LDOS at E=0 in the armchair edge. The behavior of the LDOS can be studied using scanning tunneling microscopy (STM) experiments. We suggest that care must be taken while interpreting the STM data, because the clear distinction between the zigzag edge (enhanced LDOS at E=0) and armchair edge (suppressed LDOS at E=0) can be lost if the hopping is not isotropic and if the edges are mixed.

  15. Towards an Efficient Flooding Scheme Exploiting 2-Hop Backward Information in MANETs

    NASA Astrophysics Data System (ADS)

    Le, Trong Duc; Choo, Hyunseung

    Flooding is an indispensable operation for providing control or routing functionalities to mobile ad hoc networks (MANETs). Previously, many flooding schemes have been studied with the intention of curtailing the problems of severe redundancies, contention, and collisions in traditional implementations. A recent approach with relatively high efficiency is 1HI by Liu et al., which uses only 1-hop neighbor information. The scheme achieves local optimality in terms of the number of retransmission nodes with time complexity &Theta(n log n), where n is the number of neighbors of a node; however, this method tends to make many redundant transmissions. In this paper, we present a novel flooding algorithm, 2HBI (2-hop backward information), that efficiently reduces the number of retransmission nodes and solves the broadcast storm problem in ad hoc networks using our proposed concept, “2-hop backward information.” The most significant feature of the proposed algorithm is that it does not require any extra communication overhead other than the exchange of 1-hop HELLO messages but maintains high deliverability. Comprehensive computer simulations show that the proposed scheme significantly reduces redundant transmissions in 1HI and in pure flooding, up to 38% and 91%, respectively; accordingly it alleviates contention and collisions in networks.

  16. You Know What It Is: Learning Words through Listening to Hip-Hop

    PubMed Central

    Chesley, Paula

    2011-01-01

    Music listeners have difficulty correctly understanding and remembering song lyrics. However, results from the present study support the hypothesis that young adults can learn African-American English (AAE) vocabulary from listening to hip-hop music. Non-African-American participants first gave free-response definitions to AAE vocabulary items, after which they answered demographic questions as well as questions addressing their social networks, their musical preferences, and their knowledge of popular culture. Results from the survey show a positive association between the number of hip-hop artists listened to and AAE comprehension vocabulary scores. Additionally, participants were more likely to know an AAE vocabulary item if the hip-hop artists they listen to use the word in their song lyrics. Together, these results suggest that young adults can acquire vocabulary through exposure to hip-hop music, a finding relevant for research on vocabulary acquisition, the construction of adolescent and adult identities, and the adoption of lexical innovations. PMID:22205942

  17. Hopping and the Stokes-Einstein relation breakdown in simple glass formers.

    PubMed

    Charbonneau, Patrick; Jin, Yuliang; Parisi, Giorgio; Zamponi, Francesco

    2014-10-21

    One of the most actively debated issues in the study of the glass transition is whether a mean-field description is a reasonable starting point for understanding experimental glass formers. Although the mean-field theory of the glass transition--like that of other statistical systems--is exact when the spatial dimension d → ∞, the evolution of systems properties with d may not be smooth. Finite-dimensional effects could dramatically change what happens in physical dimensions,d = 2, 3. For standard phase transitions finite-dimensional effects are typically captured by renormalization group methods, but for glasses the corrections are much more subtle and only partially understood. Here, we investigate hopping between localized cages formed by neighboring particles in a model that allows to cleanly isolate that effect. By bringing together results from replica theory, cavity reconstruction, void percolation, and molecular dynamics, we obtain insights into how hopping induces a breakdown of the Stokes-Einstein relation and modifies the mean-field scenario in experimental systems. Although hopping is found to supersede the dynamical glass transition, it nonetheless leaves a sizable part of the critical regime untouched. By providing a constructive framework for identifying and quantifying the role of hopping, we thus take an important step toward describing dynamic facilitation in the framework of the mean-field theory of glasses. PMID:25288722

  18. Crop damage caused by Powdery Mildew on Hop and its relationship to late season management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Powdery mildew of hop (Podosphaera macularis) may cause economic loss due to reductions in cone yield and quality. Quantitative estimates of crop damage from powdery mildew remain poorly characterised, especially the effect of late season disease management on crop yield and quality. Field studies i...

  19. Powdery mildew caused by Podosphaera macularis on hop (Humulus lupulus) in North Carolina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In June 2015, a grower in western North Carolina detected powdery mildew in a small hop yard. Characteristic colonies of the pathogen where observed on cultivars Cashmere, Cascade, and Chinook. Leaves with powdery mildew were collected from cultivar Cashmere for confirmation of the pathogen identi...

  20. Structure and DNA-binding of meiosis-specific protein Hop2

    NASA Astrophysics Data System (ADS)

    Zhou, Donghua; Moktan, Hem; Pezza, Roberto

    2014-03-01

    Here we report structure elucidation of the DNA binding domain of homologous pairing protein 2 (Hop2), which is important to gene diversity when sperms and eggs are produced. Together with another protein Mnd1, Hop2 enhances the strand invasion activity of recombinase Dmc1 by over 30 times, facilitating proper synapsis of homologous chromosomes. However, the structural and biochemical bases for the function of Hop2 and Mnd1 have not been well understood. As a first step toward such understanding, we recently solved the structure for the N-terminus of Hop2 (1-84) using solution NMR. This fragment shows a typical winged-head conformation with recognized DNA binding activity. DNA interacting sites were then investigated by chemical shift perturbations in a titration experiment. Information of these sites was used to guide protein-DNA docking with MD simulation, revealing that helix 3 is stably lodged in the DNA major groove and that wing 1 (connecting strands 2 and 3) transiently comes in contact with the minor groove in nanosecond time scale. Mutagenesis analysis further confirmed the DNA binding sites in this fragment of the protein.

  1. Interaction and dynamics of homologous pairing protein 2 (HOP2) and DNA studied by MD simulation

    NASA Astrophysics Data System (ADS)

    Moktan, Hem; Pezza, Roberto; Zhou, Donghua

    2015-03-01

    The homologous pairing protein 2 (Hop2) plays an important role in meiosis and DNA repair. Together with protein Mnd1, Hop2 enhances the strand invasion activity of recombinase Dmc1 by over 30 times, facilitating proper synapsis of homologous chromosomes. We recently determined the NMR structure of the N-terminal domain of Hop2 and proposed a model of Protein-DNA complex based on NMR chemical shift perturbations and mutagenesis studies (Moktan, J Biol Chem 2014 10.1074/jbc.M114.548180). However structure and dynamics of the complex have not been studied at the atomic level yet. Here, we used classical MD simulations to study the interactions between the N-terminal HOP2 and DNA. The simulated results indicate that helix3 (H3) interacts with DNA in major groove and wing1 (W1) interacts mostly in minor groove mainly via direct hydrogen bonds. Also it is found that binding leads to reduced fluctuations in both protein and DNA. Several water bridge interactions have been identified. The residue-wise contributions to the interaction energy were evaluated. Also the functional motion of the protein is analyzed using principal component analysis. The results confirmed the importance of H3 and W1 for the stability of the complex, which is consistent with our previous experimental studies.

  2. Slouching toward Bork: The Culture Wars and Self-Criticism in Hip-Hop Music.

    ERIC Educational Resources Information Center

    Ogbar, Jeffrey O. G.

    1999-01-01

    Examined the marginalized voices of hip-hop artists in the culture war debates of the 1990s. Explores the efficacy of those voices and reveals how they differ from the typical parameter of public debate. Discusses the attacks on rap by right wing thinkers, such as Newt Gingrich and Robert Bork. (SLD)

  3. Black wilt of hop (Humulus lupulus) caused by Diplodia seriata in New York State

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In August 2012, wilted hop bines were observed in a yard near Seneca Castle, New York, affecting 10 to 20% of the plants. Affected bines had a dark stem discoloration and wilted leaves, which remained attached after bines were killed. Dark brown to black erumpent pycnidia were aggregated in the cor...

  4. Identification of extrachromosomal circular DNA in hop via rolling circle amplification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During a survey looking for viruses affecting hop plants in the Willamette Valley of Oregon, a circular DNA molecule was identified via rolling circle amplification (RCA) and later characterized. The 5.7 kb long molecule only matched in a minor cover to a microsatellite region in the Humulus lupulus...

  5. Red crown rot of Hop in Oregon caused by Phomopsis tuberivora

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During July 2007, a hop grower in Marion County, Oregon reported weak growth and death of plants of cultivar Fuggle. Affected plants were aggregated within and among rows, and had underdeveloped lateral branches, uneven and weak bines, and chlorotic leaves; severely affected plants were dead. The p...

  6. Effect of assisted hopping on thermopower in an interacting quantum dot

    NASA Astrophysics Data System (ADS)

    Tooski, S. B.; Ramšak, A.; Bułka, B. R.; Žitko, R.

    2014-05-01

    We investigate the electrical conductance and thermopower of a quantum dot tunnel coupled to external leads described by an extension of the Anderson impurity model which takes into account the assisted hopping processes, i.e., the occupancy-dependence of the tunneling amplitudes. We provide analytical understanding based on scaling arguments and the Schrieffer-Wolff transformation, corroborated by detailed numerical calculations using the numerical renormalization group method. The assisted hopping modifies the coupling to the two-particle state, which shifts the Kondo exchange coupling constant and exponentially reduces or enhances the Kondo temperature, breaks the particle-hole symmetry, and strongly affects the thermopower. We discuss the gate-voltage and temperature dependence of the transport properties in various regimes. For a particular value of the assisted hopping parameter we find peculiar discontinuous behaviour in the mixed-valence regime. Near this value, we find very high Seebeck coefficient. We show that, quite generally, the thermopower is a highly sensitive probe of assisted hopping and Kondo correlations.

  7. Sequential sampling for estimation and classification of the incidence of hop powdery mildew II: Cone sampling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sequential sampling models for estimation and classification of the incidence of powdery mildew (caused by Podosphaera macularis) on hop (Humulus lupulus) cones were developed using parameter estimates of the binary power law derived from the analysis of 221 transect data sets (model construction da...

  8. Comparative proteomic profiling in compatible and incompatible interactions between hop roots and Verticillium albo-atrum.

    PubMed

    Mandelc, Stanislav; Timperman, Isaak; Radišek, Sebastjan; Devreese, Bart; Samyn, Bart; Javornik, Branka

    2013-07-01

    Verticillium wilt, caused by the soil borne fungal pathogen Verticillium albo-atrum, is a serious threat to hop (Humulus lupulus L.) production in several hop-growing regions. A proteomic approach was applied to analyse the response of root tissue in compatible and incompatible interactions between hop and V. albo-atrum at 10, 20 and 30 days after inoculation, using two-dimensional difference gel electrophoresis (2D-DIGE) coupled with de novo sequencing of derivatized peptides. Approximately 1200 reproducible spots were detected on the gels, of which 102 were identified. In the compatible interaction, 252 spots showed infection-specific changes in spot abundance and an accumulation of defence-related proteins, such as chitinase, β-glucanase, thaumatin-like protein, peroxidase and germin-like protein, was observed. However, no significant infection-specific changes were detected in the incompatible interaction. The results indicate that resistance in this pathosystem may be conferred by constitutive rather than induced defence mechanisms. The identification and high abundance of two mannose/glucose-specific lectin isoforms present only in the roots of the resistant cultivar suggests function of lectins in hop resistance against V. albo-atrum. PMID:23619241

  9. Complete Genome Sequence of a Carnation Mottle Virus Infecting Hop Plants

    PubMed Central

    Jo, Yeonhwa; Choi, Hoseong

    2015-01-01

    The Carnation mottle virus (CarMV) is a single positive-strand RNA virus belonging to the genus Carmovirus. The major natural host for CarMV is the carnation. In this study, using transcriptome data, we provide for the first time a nearly complete genome sequence of CarMV infecting hop plants. PMID:25977420

  10. Charge Energy Transport in Hopping Systems with Rapidly Decreasing Density of States

    NASA Astrophysics Data System (ADS)

    Mendels, Dan; Organic Electronics Group Technion Team

    2014-03-01

    An accurate description of the carrier hopping topology in the energy domain of hopping systems incorporating a rapidly decreasing density of states and the subsequent energetic position of these systems' so called effective conduction band is crucial for rationalizing and quantifying these systems' thermo-electric properties, doping related phenomena and carrier gradient effects such as the emergence of the General Einstein Relation under degenerate conditions. Additionally, as will be shown, the 'mobile' carriers propagating through the system can have excess energies reaching 0.3eV above the system quasi-Fermi energy. Hence, since these mobile carriers are most prone to reach systems interfaces and interact with oppositely charged carriers, their excess energy should be considered in determining the efficiencies of energy dependent processes such as carrier recombination and exciton dissociation. In light of the stated motivations, a comprehensive numerical and analytical study of the topology of hopping in the energetic density of such systems (i.e. the statistics regarding which energy values carriers visit most and in what manner) was implemented and the main statistical features of the hopping process that determine the position in energy of the system's effective conduction band were distilled. The obtained results also help shed light on yet to be elucidated discrepancies between predictions given by the widely employed transport energy concept and Monte Carlo simulations.

  11. Slam: Hip-Hop Meets Poetry--A Strategy for Violence Intervention.

    ERIC Educational Resources Information Center

    Bruce, Heather E.; Davis, Bryan Dexter

    2000-01-01

    Describes one strategy used in high school English classrooms to teach for peace and dislodge violence: the poetry slam, a burgeoning pop culture phenomenon that combines poetry and performance art. Describes poetry slams that incorporate hip-hop culture. Discusses promoting slams in English classrooms to show students the power of words and…

  12. SPE-39 family proteins interact with the HOPS complex and function in lysosomal delivery.

    PubMed

    Zhu, Guang-dan; Salazar, Gloria; Zlatic, Stephanie A; Fiza, Babar; Doucette, Michele M; Heilman, Craig J; Levey, Allan I; Faundez, Victor; L'hernault, Steven W

    2009-02-01

    Yeast and animal homotypic fusion and vacuole protein sorting (HOPS) complexes contain conserved subunits, but HOPS-mediated traffic in animals might require additional proteins. Here, we demonstrate that SPE-39 homologues, which are found only in animals, are present in RAB5-, RAB7-, and RAB11-positive endosomes where they play a conserved role in lysosomal delivery and probably function via their interaction with the core HOPS complex. Although Caenorhabditis elegans spe-39 mutants were initially identified as having abnormal vesicular biogenesis during spermatogenesis, we show that these mutants also have disrupted processing of endocytosed proteins in oocytes and coelomocytes. C. elegans SPE-39 interacts in vitro with both VPS33A and VPS33B, whereas RNA interference of VPS33B causes spe-39-like spermatogenesis defects. The human SPE-39 orthologue C14orf133 also interacts with VPS33 homologues and both coimmunoprecipitates and cosediments with other HOPS subunits. SPE-39 knockdown in cultured human cells altered the morphology of syntaxin 7-, syntaxin 8-, and syntaxin 13-positive endosomes. These effects occurred concomitantly with delayed mannose 6-phosphate receptor-mediated cathepsin D delivery and degradation of internalized epidermal growth factor receptors. Our findings establish that SPE-39 proteins are a previously unrecognized regulator of lysosomal delivery and that C. elegans spermatogenesis is an experimental system useful for identifying conserved regulators of metazoan lysosomal biogenesis. PMID:19109425

  13. SPE-39 Family Proteins Interact with the HOPS Complex and Function in Lysosomal Delivery

    PubMed Central

    Zhu, Guang-dan; Salazar, Gloria; Zlatic, Stephanie A.; Fiza, Babar; Doucette, Michele M.; Heilman, Craig J.; Levey, Allan I.

    2009-01-01

    Yeast and animal homotypic fusion and vacuole protein sorting (HOPS) complexes contain conserved subunits, but HOPS-mediated traffic in animals might require additional proteins. Here, we demonstrate that SPE-39 homologues, which are found only in animals, are present in RAB5-, RAB7-, and RAB11-positive endosomes where they play a conserved role in lysosomal delivery and probably function via their interaction with the core HOPS complex. Although Caenorhabditis elegans spe-39 mutants were initially identified as having abnormal vesicular biogenesis during spermatogenesis, we show that these mutants also have disrupted processing of endocytosed proteins in oocytes and coelomocytes. C. elegans SPE-39 interacts in vitro with both VPS33A and VPS33B, whereas RNA interference of VPS33B causes spe-39–like spermatogenesis defects. The human SPE-39 orthologue C14orf133 also interacts with VPS33 homologues and both coimmunoprecipitates and cosediments with other HOPS subunits. SPE-39 knockdown in cultured human cells altered the morphology of syntaxin 7-, syntaxin 8-, and syntaxin 13-positive endosomes. These effects occurred concomitantly with delayed mannose 6-phosphate receptor-mediated cathepsin D delivery and degradation of internalized epidermal growth factor receptors. Our findings establish that SPE-39 proteins are a previously unrecognized regulator of lysosomal delivery and that C. elegans spermatogenesis is an experimental system useful for identifying conserved regulators of metazoan lysosomal biogenesis. PMID:19109425

  14. Becoming Black: Rap and Hip Hop, Race, Gender, Identity, and the Politics of ESL Learning.

    ERIC Educational Resources Information Center

    Ibrahim, Awad El Karim M.

    1999-01-01

    Examines how a group of continental Francophone African youth at a French high school in Ottawa, Canada "become Black" as they enter a world that already constructs them as Black. These students learn Black English, which they access in hip-hop culture and linguistic styles. Discusses the impact of becoming Black on English-as-a-Second-Language…

  15. Characterization of resistance to powdery mildew in the Hop cultivars Newport and Comet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop powdery mildew, caused by Podosphaera macularis, is an important disease in the Northwestern U.S. Outbreaks of powdery mildew on cultivars previously resistant to the disease have been reported increasingly with the emergence of virulent pathogen strains capable of overcoming a commonly deployed...

  16. Method Development and Validation for UHPLC-MS-MS Determination of Hop Prenylflavonoids in Human Serum

    PubMed Central

    Yuan, Yang; Qiu, Xi; Nikolic, Dejan; Dahl, Jeffrey H.; van Breemen, Richard B.

    2013-01-01

    Hops (Humulus lupulus L.) are used in the brewing of beer, and hop extracts containing prenylated compounds such as xanthohumol and 8-prenylnaringenin are under investigation as dietary supplements for cancer chemoprevention and for the management of hot flashes in menopausal women. To facilitate clinical studies of hop safety and efficacy, a selective, sensitive, and fast ultra-high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS-MS) method was developed and validated for the simultaneous determination of the hop prenylflavonoids xanthohumol, isoxanthohumol, 6-prenylnaringenin, and 8-prenylnaringenin in human serum. The analytical method requires 300 μL of human serum which is processed using liquid-liquid extraction. UHPLC separation was carried out in 2.5 min with gradient elution using a reversed phase column containing 1.6 μm packing material. Prenylflavonoids were measured using negative ion electrospray mass spectrometry with collision-induced dissociation and selected reaction monitoring. The method was validated and showed good accuracy and precision with a lower limit of quantitation (LLOQ) of 0.50 ng/mL for XN (1.4 nM) and 1.0 ng/mL for 6-PN (2.8 nM), XN and IX (2.9 nM) in serum for each analyte. PMID:23451393

  17. Scaffold hopping towards potent and selective JAK3 inhibitors: discovery of novel C-5 substituted pyrrolopyrazines.

    PubMed

    de Vicente, Javier; Lemoine, Remy; Bartlett, Mark; Hermann, Johannes C; Hekmat-Nejad, Mohammad; Henningsen, Robert; Jin, Sue; Kuglstatter, Andreas; Li, Hongju; Lovey, Allen J; Menke, John; Niu, Linghao; Patel, Vaishali; Petersen, Ann; Setti, Lina; Shao, Ada; Tivitmahaisoon, Parcharee; Vu, Minh Diem; Soth, Michael

    2014-11-01

    The discovery of a novel series of pyrrolopyrazines as JAK inhibitors with comparable enzyme and cellular activity to tofacitinib is described. The series was identified using a scaffold hopping approach aided by structure based drug design using principles of intramolecular hydrogen bonding for conformational restriction and targeting specific pockets for modulating kinase activity. PMID:25262541

  18. Estimation of the Mutual Time Delay of Signals with Pseudorandom Frequency Hopping

    NASA Astrophysics Data System (ADS)

    Ershov, R. A.; Morozov, O. A.; Fidelman, V. R.

    2015-07-01

    We propose a method for determining the mutual time delay during the propagation of signals with pseudorandom frequency hopping in different channels. A modified algorithm for calculating the uncertainty function, which permits calculation parallelization, is used to compensate for the influence of the Doppler effect during the signal recording. The results of studying the efficiency of the proposed method are presented.

  19. Dynamic control of muscle stiffness and H reflex modulation during hopping and jumping in man.

    PubMed Central

    Dyhre-Poulsen, P; Simonsen, E B; Voigt, M

    1991-01-01

    1. The objective of the study was to evaluate the functional effects of reflexes on muscle mechanics during natural voluntary movements. The excitability of the H (Hoffmann) reflex was used as a measure of the excitability of the central component of the stretch reflex. 2. We recorded EMG, ground reaction forces and the H reflex in the soleus muscle in humans while landing from a downward jump, during drop jumping and during hopping. The movements were also recorded by high-speed cinematography. 3. The EMG pattern was adapted to the motor task. When landing the EMG in the soleus muscle and in the anterior tibial muscle showed preinnervation and alternating activity after touch down. When hopping there was little preinnervation in the soleus muscle, and the activity was initiated about 45 ms after touch down by a peak and continued unbroken until lift off. In the drop jumps the EMG pattern depended on the jumping style used by the subject. 4. The H reflex in the soleus muscle was strongly modulated in a manner appropriate to the requirements of the motor task. During landing from a downward jump the H reflex was low at touch down whereas while hopping it was high at touch down. During drop jumping it was variable and influenced by the jumping technique. 5. Muscle stiffness in the ankle joint was negative after touch down when landing, but always positive when hopping. 6. It is suggested that during landing the alternating EMG pattern after touch down was programmed and little influenced by reflexes. During hopping reflexes could contribute to the initial peak and the EMG during lift off. 7. The programmed EMG activity and the suppression of the H reflex while landing probably contribute to the development of the negative stiffness and change the muscles from a spring to a damping unit. PMID:1890636

  20. Systematic assessment of scaffold hopping versus activity cliff formation across bioactive compound classes following a molecular hierarchy.

    PubMed

    Stumpfe, Dagmar; Dimova, Dilyana; Bajorath, Jürgen

    2015-07-01

    Scaffold hopping and activity cliff formation define opposite ends of the activity landscape feature spectrum. To rationalize these events at the level of scaffolds, active compounds involved in scaffold hopping were required to contain topologically distinct scaffolds but have only limited differences in potency, whereas compounds involved in activity cliffs were required to share the same scaffold but have large differences in potency. A systematic search was carried out for compounds involved in scaffold hopping and/or activity cliff formation. Results obtained for compound data sets covering more than 300 human targets revealed clear trends. If scaffolds represented multiple but fewer than 10 active compounds, nearly 90% of all scaffolds were exclusively involved in hopping events. With increasing compound coverage, the fraction of scaffolds involved in both scaffold hopping and activity cliff formation significantly increased to more than 50%. However, ∼40% of the scaffolds representing large numbers of active compounds continued to be exclusively involved in scaffold hopping. More than 200 scaffolds with broad target coverage were identified that consistently represented potent compounds and yielded an abundance of scaffold hops in the low-nanomolar range. These and other subsets of scaffolds we characterized are of prime interest for structure-activity relationship (SAR) exploration and compound design. Therefore, the complete scaffold classification generated in the course of our analysis is made freely available. PMID:25982076

  1. Probing radiation damage by alternated current conductivity as a method to characterize electron hopping conduction in DNA molecules

    SciTech Connect

    Gomes, Paulo J.; Coelho, Margarida; Antonio Ribeiro, Paulo; Raposo, Maria; Dionisio, Madalena

    2012-09-17

    Analysis of AC electrical conductivity of deoxyribonucleic acid (DNA) thin films, irradiated with ultraviolet (UV) light, revealed that electrical conduction arises from DNA chain electron hopping between base-pairs and phosphate groups. The hopping distance calculated from correlated barrier hopping model equals the distance between DNA base-pairs, which is consistent with the loss of conductivity with irradiation time arising from a decrease in phosphates groups. In the high frequency regime, at a given frequency, real part of conductivity strongly depends on irradiation time particularly for low dose levels suggesting the use of DNA based films for UV radiation sensors.

  2. Mode-hop-free operation of a distributed Bragg reflector diode laser in an external fiber-cavity configuration

    NASA Astrophysics Data System (ADS)

    Kawai, Yuji; Tanaka, Utako; Hayasaka, Kazuhiro; Urabe, Shinji

    2015-11-01

    We report on the mode-hop-free operation of a distributed Bragg reflector (DBR) diode laser with an external cavity consisting of an optical fiber. A simple method is implemented, using feedback to the DBR drive current, to suppress mode hops due to frequency mismatch between the intrinsic mode of the DBR laser and the resonant mode of the fiber cavity. The error signal is derived from the change in the output power of the whole system. The feedback allows long-term operation over hours without mode hops, as well as continuous frequency scans of about 1 GHz with a reduced short-term linewidth.

  3. Hopping conduction range of heavily Al-doped 4H-SiC thick epilayers grown by CVD

    NASA Astrophysics Data System (ADS)

    Ji, Shiyang; Eto, Kazuma; Yoshida, Sadafumi; Kojima, Kazutoshi; Ishida, Yuuki; Saito, Shingo; Tsuchida, Hidekazu; Okumura, Hajime

    2015-12-01

    To outline the hopping conduction range, the electrical characteristics of CVD-grown heavily Al-doped 4H-SiC thick epilayers (2.0 × 1019-4.0 × 1020 cm-3) were investigated in a wide temperature regime (20-900 K). It is found that, below 100 K, hopping conduction dominates the carrier transport for all epilayers, and the corresponding hopping conduction activation energy shows a maximum of ˜30 meV at around 1.1 × 1020 cm-3. With increasing doping level, the temperature dependence of resistivity evolves and finally obeys the ˜1/T1/4 law in the entire temperature regime, which gives direct evidence of variable-range hopping conduction.

  4. Charge Diffusion in Semiconducting Polymers: Analytical Relation between Polymer Rigidity and Time Scales for Intrachain and Interchain Hopping.

    PubMed

    Carbone, Paola; Troisi, Alessandro

    2014-08-01

    We study the charge diffusion of semiconducting polymer bulk using simplified coarse grained models to investigate the relation between charge diffusion coefficient and the characteristics time of intrachain and interchain hopping, τ1 and τ2. We consider the process of charge diffusion in several standard models of polymer chains (rigid chain, Gaussian chain, worm-like chain), and we achieve an analytical expression for the diffusion coefficient in terms of the characteristic times and the geometric parameters defining the chain models. The diffusion depends only on the intrachain hopping for the rigid chain and on the geometric average of intrachain and interchain hopping times for the Gaussian chain (the least rigid model), with an analytical interpolation available between two limits. The model highlights the importance of large persistence lengths for improved transport properties. In all cases, it is incorrect to consider the slower interchain hopping as the rate-determining step for the charge transport. PMID:26277956

  5. Differences between direct current and alternating current capacitance nonlinearities in high-k dielectrics and their relation to hopping conduction

    NASA Astrophysics Data System (ADS)

    Khaldi, O.; Gonon, P.; Vallée, C.; Mannequin, C.; Kassmi, M.; Sylvestre, A.; Jomni, F.

    2014-08-01

    Capacitance nonlinearities were studied in atomic layer deposited HfO2 films using two types of signals: a pure ac voltage of large magnitude (ac nonlinearities) and a small ac voltage superimposed to a large dc voltage (dc nonlinearities). In theory, ac and dc nonlinearities should be of the same order of magnitude. However, in practice, ac nonlinearities are found to be an order of magnitude higher than dc nonlinearities. Besides capacitance nonlinearities, hopping conduction is studied using low-frequency impedance measurements and is discussed through the correlated barrier hopping model. The link between hopping and nonlinearity is established. The ac nonlinearities are ascribed to the polarization of isolated defect pairs, while dc nonlinearities are attributed to electrode polarization which originates from defect percolation paths. Both the ac and dc capacitance nonlinearities display an exponential variation with voltage, which results from field-induced lowering of the hopping barrier energy.

  6. Differences between direct current and alternating current capacitance nonlinearities in high-k dielectrics and their relation to hopping conduction

    SciTech Connect

    Khaldi, O.; Kassmi, M.; Gonon, P. Vallée, C.; Mannequin, C.; Sylvestre, A.; Jomni, F.

    2014-08-28

    Capacitance nonlinearities were studied in atomic layer deposited HfO{sub 2} films using two types of signals: a pure ac voltage of large magnitude (ac nonlinearities) and a small ac voltage superimposed to a large dc voltage (dc nonlinearities). In theory, ac and dc nonlinearities should be of the same order of magnitude. However, in practice, ac nonlinearities are found to be an order of magnitude higher than dc nonlinearities. Besides capacitance nonlinearities, hopping conduction is studied using low-frequency impedance measurements and is discussed through the correlated barrier hopping model. The link between hopping and nonlinearity is established. The ac nonlinearities are ascribed to the polarization of isolated defect pairs, while dc nonlinearities are attributed to electrode polarization which originates from defect percolation paths. Both the ac and dc capacitance nonlinearities display an exponential variation with voltage, which results from field-induced lowering of the hopping barrier energy.

  7. Targeted analysis of polyphenol metabolism during development of hop (Humulus lupulus L.) cones following treatment with prohexadione-calcium.

    PubMed

    Kavalier, Adam R; Ma, Chunhui; Figueroa, Mario; Kincaid, Dwight; Matthews, Paul D; Kennelly, Edward J

    2014-02-15

    Hops (Humulus lupulus), a main ingredient in beer, are valued as a source of bitter flavour and biologically active polyphenols. We treated immature hop cones with prohexadione-calcium (Pro-Ca), a flavanone-3-hydroxylase (F3H) inhibitor, to perturb the flavonoid pathway, and conducted a targeted analysis of 29 compounds from the phenolic acid, flavonoid, and terpenophenolic pathways, using photodiode array (UHPLC-PDA), and time of flight mass spectrometry (LC-TOF-MS) analysis. Hop cones were analysed over four stages of development spanning 22days following Pro-Ca treatment. The content of terpenophenolics as well as metabolic precursors upstream from F3H significantly increased, and levels of flavonoid products downstream from F3H decreased. The methods developed here serve to compliment flavour analysis of polyphenol rich foods, and our results suggest ways to improve upon traditional agricultural methods to produce hops with altered chemical profiles. PMID:24128475

  8. Linear center-of-mass dynamics emerge from non-linear leg-spring properties in human hopping.

    PubMed

    Riese, Sebastian; Seyfarth, Andre; Grimmer, Sten

    2013-09-01

    Given the almost linear relationship between ground-reaction force and leg length, bouncy gaits are commonly described using spring-mass models with constant leg-spring parameters. In biological systems, however, spring-like properties of limbs may change over time. Therefore, it was investigated how much variation of leg-spring parameters is present during vertical human hopping. In order to do so, rest-length and stiffness profiles were estimated from ground-reaction forces and center-of-mass dynamics measured in human hopping. Trials included five hopping frequencies ranging from 1.2 to 3.6 Hz. Results show that, even though stiffness and rest length vary during stance, for most frequencies the center-of-mass dynamics still resemble those of a linear spring-mass hopper. Rest-length and stiffness profiles differ for slow and fast hopping. Furthermore, at 1.2 Hz two distinct control schemes were observed. PMID:23880438

  9. First- and Second-Order Phase Transition in Parallel Triple Quantum Dots: The Roles of Symmetric and Asymmetric Hopping

    NASA Astrophysics Data System (ADS)

    Xiong, Yong-Chen

    2014-11-01

    By means of the numerical renormalization group method, I study the quantum phase transition (QPT) and the electronic transport in parallel triple quantum dot system with symmetric and/or asymmetric hopping. For symmetric hopping and zero magnetic field , I find a first order transition between spin quadruplet and doublet as () increases. With increasing , a second order QPT between of the doublet and of the quadruplet is observed. For asymmetric hopping , the QPT depends closely on the other hopping. For fixed , where is the hybridization function between the dots and the leads, a first order transition is observed as increases, while for , a crossover occurs. In the presence of , the transition between and is a first order QPT for , while a second order for.

  10. Wavelength Requirements for a Scalable Multicast Single-Hop Wdm Network

    NASA Astrophysics Data System (ADS)

    Yousif, Rabi W.; Ali, Borhanuddin Mohd; Abdullah, Mohd Khazani; Seman, Kamaruzzaman Bin; Baba, Mohd Dani

    2010-06-01

    In this paper, we present a method for designing a passive optical based single-hop wavelength division multiplexing multicast architecture that can achieve a scalable structure and form the basis of a wavelength efficient single-hop WDM network. The proposed architecture minimizes the number of wavelengths required for efficient multicast service and also minimizes tunability requirement of the transceivers. The network size scalability is achieved by adding transmitters and receivers to the designated groups. We show that the proposed system can accommodate large tuning delays and keeps with suitable throughput when the number of wavelength is equal to the number of nodes. We also show that the design can lead to a scalable structure while minimizing the number of wavelengths and tunability of the transceivers required for an efficient multicast service resulting in an improved system throughput and delay performance.

  11. Structure-aware Bayesian compressive sensing for frequency-hopping spectrum estimation

    NASA Astrophysics Data System (ADS)

    Liu, Shengheng; Zhang, Yimin D.; Shan, Tao; Qin, Si; Amin, Moeness G.

    2016-05-01

    Frequency-hopping (FH) is one of the commonly used spread spectrum techniques that finds wide applications in communications and radar systems due to its capability of low probability of intercept, reduced interference, and desirable ambiguity property. In this paper, we consider the blind estimation of the instantaneous FH spectrum without the knowledge of hopping patterns. The FH signals are analyzed in the joint time-frequency domain, where FH signals manifest themselves as sparse entries, thus inviting compressive sensing and sparse reconstruction techniques for FH spectrum estimation. In particular, the signals' piecewise-constant frequency characteristics are exploited in the reconstruction of sparse quadratic time-frequency representations. The Bayesian compressive sensing methods are applied to provide high-resolution frequency estimation. The FH spectrum characteristics are used in the design of signal-dependent kernel within the framework of structure-aware sparse reconstruction.

  12. Kinetic equations for hopping transport and spin relaxation in a random magnetic field

    NASA Astrophysics Data System (ADS)

    Shumilin, A. V.; Kabanov, V. V.

    2015-07-01

    We derive the kinetic equations for a hopping transport that take into account an electron spin and the possibility of double occupation. In the Ohmic regime, the equations are reduced to the generalized Miller-Abrahams resistor network. We apply these equations to the problem of the magnetic moment relaxation due to the interaction with the random hyperfine fields. It is shown that in a wide range of parameters the relaxation rate is governed by the hops with the similar rates as spin precession frequency. It is demonstrated that at the large time scale spin relaxation is nonexponential. We argue that the nonexponential relaxation of the magnetic moment is related to the spin of electrons in the slow-relaxing traps. Interestingly, the traps can significantly influence the spin relaxation in the infinite conducting cluster at large times.

  13. PLEKHM1 regulates autophagosome-lysosome fusion through HOPS complex and LC3/GABARAP proteins.

    PubMed

    McEwan, David G; Popovic, Doris; Gubas, Andrea; Terawaki, Seigo; Suzuki, Hironori; Stadel, Daniela; Coxon, Fraser P; Miranda de Stegmann, Diana; Bhogaraju, Sagar; Maddi, Karthik; Kirchof, Anja; Gatti, Evelina; Helfrich, Miep H; Wakatsuki, Soichi; Behrends, Christian; Pierre, Philippe; Dikic, Ivan

    2015-01-01

    The lysosome is the final destination for degradation of endocytic cargo, plasma membrane constituents, and intracellular components sequestered by macroautophagy. Fusion of endosomes and autophagosomes with the lysosome depends on the GTPase Rab7 and the homotypic fusion and protein sorting (HOPS) complex, but adaptor proteins that link endocytic and autophagy pathways with lysosomes are poorly characterized. Herein, we show that Pleckstrin homology domain containing protein family member 1 (PLEKHM1) directly interacts with HOPS complex and contains a LC3-interacting region (LIR) that mediates its binding to autophagosomal membranes. Depletion of PLEKHM1 blocks lysosomal degradation of endocytic (EGFR) cargo and enhances presentation of MHC class I molecules. Moreover, genetic loss of PLEKHM1 impedes autophagy flux upon mTOR inhibition and PLEKHM1 regulates clearance of protein aggregates in an autophagy- and LIR-dependent manner. PLEKHM1 is thus a multivalent endocytic adaptor involved in the lysosome fusion events controlling selective and nonselective autophagy pathways. PMID:25498145

  14. On the accuracy of surface hopping dynamics in condensed phase non-adiabatic problems

    NASA Astrophysics Data System (ADS)

    Chen, Hsing-Ta; Reichman, David R.

    2016-03-01

    We perform extensive benchmark comparisons of surface hopping dynamics with numerically exact calculations for the spin-boson model over a wide range of energetic and coupling parameters as well as temperature. We find that deviations from golden-rule scaling in the Marcus regime are generally small and depend sensitively on the energetic bias between electronic states. Fewest switches surface hopping (FSSH) is found to be surprisingly accurate over a large swath of parameter space. The inclusion of decoherence corrections via the augmented FSSH algorithm improves the accuracy of dynamical behavior compared to exact simulations, but the effects are generally not dramatic, at least for the case of an environment modeled with the commonly used Debye spectral density.

  15. Periodic one-dimensional hopping model with transitions between nonadjacent states.

    PubMed

    Zhang, Yunxin

    2011-09-01

    A one-dimensional hopping model is useful for describing the motion of microscopic particles in a thermal noise environment. Recent experiments on the new generation of light-driven rotary molecular motors found that a motor in state i can jump forward to state i+1 or i+2 or backward to state i-1 or i-2 directly. In this paper, inspired by these experiments, such a modified periodic one-dimensional hopping model with arbitrary period N is studied theoretically. The mean velocity, effective diffusion constant, and mean dwell time in one single mechanochemical cycle are obtained. The corresponding results are illustrated and verified by being applied to the synthetic rotary molecular motors. PMID:22060325

  16. Jamming effects on code synchronization of burst-mode frequency-hop spread-spectrum

    NASA Astrophysics Data System (ADS)

    van Grouw, Mike G.; Wicker, Mark A.

    The authors characterize the performance of a multiple-dwell FHSS (frequency-hopping spread-spectrum) code synchronization scheme in the presence of channel dynamics. Random hop jamming is assumed. The coarse acquisition system uses both passive and active correlation to implement a serial search of the code-uncertainty region. The in-lock monitoring is accomplished using a two-dwell active correlator with a relatively long integration time. Both burst- and continuous-mode communications links are considered. Appropriate performance parameters are developed, and design considerations are discussed. Performance curves are given for the various cases considered. Although a fixed-threshold multiple-dwell synchronization scheme adequately mitigates the effects of dynamic jamming in a continuous-mode communications link, it is shown to be inadequate for a burst-mode communications link.

  17. Gender Differences in Leg Stiffness and Stiffness Recruitment Strategy During Two-Legged Hopping

    PubMed Central

    Padua, Darin A.; Arnold, Brent L.; Carcia, Christopher R.; Granata, Kevin P.

    2006-01-01

    The authors compared leg stiffness (KVERT), muscle activation, and joint movement patterns between 11 men and 10 women during hopping. Physically active and healthy men and women performed continuous 2-legged hopping at their preferred rate and at 3.0 Hz. Compared with men, women demonstrated decreased KVERT; however, after the authors normalized for body mass, gender differences in KVERT were eliminated. In comparison with men, women also demonstrated increased quadriceps and soleus activity, as well as greater quadriceps-to-hamstrings coactivation ratios. There were no significant gender differences for joint movement patterns (p > .05). The relationship between the observed gender differences in muscle recruitment and the increased risk of anterior cruciate ligament injury in women requires further study. PMID:15730945

  18. Electron flow through biological molecules: Does hole hopping protect proteins from oxidative damage?

    PubMed Central

    Winkler, Jay R.; Gray, Harry B.

    2016-01-01

    Biological electron transfers often occur between metal-containing cofactors that are separated by very large molecular distances. Employing photosensitizer-modified iron and copper proteins, we have shown that single-step electron tunneling can occur on nanosecond to microsecond timescales at distances between 15 and 20 angstroms. We also have shown that charge transport can occur over even longer distances by hole hopping (multistep tunneling) through intervening tyrosines and tryptophans. In this Perspective, we advance the hypothesis that such hole hopping through Tyr/Trp chains could protect oxygenase, dioxygenase, and peroxidase enzymes from oxidative damage. In support of this view, by examining the structures of P450 (CYP102A) and 2OG-Fe (TauD) enzymes, we have identified candidate Tyr/Trp chains that could transfer holes from uncoupled high-potential intermediates to reductants in contact with protein surface sites. PMID:26537399

  19. Ability of prenylflavanones present in hops to induce apoptosis in a human Burkitt lymphoma cell line.

    PubMed

    Diller, Reinhard A; Riepl, Herbert M; Rose, Oliver; Frias, Corazon; Henze, Günter; Prokop, Aram

    2007-07-01

    The identification of effective cancer preventive compounds from hops has become an important issue in public health-related research. We compared the antiproliferative and apoptosis-inducing effects of side chain variants of prenylflavanones, e. g., 8-prenylnaringenin (7) and 8-geranylnaringenin (10), which have been identified in hops (Humulus lupulus), and their synthetic variations 8-furanmethylnaringenin (8) and 8-cinnamylnaringenin (9). These were accessible by a Mitsunobu reaction and Claisen rearrangement. Flavanones 9 and 10 showed cytotoxic and apoptotic activities. Apoptosis was induced in a mitochondrial dependent manner. 8-Cinnamylnaringenin (9) displayed noticeably improved apoptotic effects when compared to 8-prenylnaringenin. The potential of 8-prenylnaringenin (7) is shown in an ex vivo experiment on a multi-drug resistant leukaemia blast. PMID:17715491

  20. Long-range electron transfer across Peptide bridges: the transition from electron superexchange to hopping.

    PubMed

    Malak, Rouba Abdel; Gao, Zhinong; Wishart, James F; Isied, Stephan S

    2004-11-01

    Long-range electron transfer rate constants for complexes of the type [(bpy)2RuIIL-Pron-apyRuIII)(NH3)5]5++ proline residues (n) varying from 0 to 9 were determined by complementary electron pulse radiolysis and flash photolysis techniques from the picosecond to the millisecond time scales. The activationless kmax values from both techniques coalesce into one data set. The distance dependence of the reactions is consistent with a smooth transition from a superexchange mechanism with attenuation constant beta = 1.4 A-1 to a hopping mechanism with attenuation constant beta = 0.17 A-1. The transition occurs between n = 3 and 4 prolines, and the virtual hopping rate constant at the shortest distance is about 1 x 106 times slower than that observed for the superexchange value. PMID:15506726

  1. Error correction coding for frequency-hopping multiple-access spread spectrum communication systems

    NASA Technical Reports Server (NTRS)

    Healy, T. J.

    1982-01-01

    A communication system which would effect channel coding for frequency-hopped multiple-access is described. It is shown that in theory coding can increase the spectrum utilization efficiency of a system with mutual interference to 100 percent. Various coding strategies are discussed and some initial comparisons are given. Some of the problems associated with implementing the type of system described here are discussed.

  2. An Efficient Scheme of Quantum Wireless Multi-hop Communication using Coefficient Matrix

    NASA Astrophysics Data System (ADS)

    Zhao, Bei; Zha, Xin-Wei; Duan, Ya-Jun; Sun, Xin-Mei

    2015-08-01

    By defining the coefficient matrix, a new quantum teleportation scheme in quantum wireless multi-hop network is proposed. With the help of intermediate nodes, an unknown qubit state can be teleported between two distant nodes which do not share entanglement in advance. Arbitrary Bell pairs and entanglement swapping are utilized for establishing quantum channel among intermediate nodes. Using collapsed matrix, the initial quantum state can be perfectly recovered at the destination.

  3. Hip-hop solutions of the 2N-body problem

    NASA Astrophysics Data System (ADS)

    Barrabés, Esther; Cors, Josep Maria; Pinyol, Conxita; Soler, Jaume

    2006-05-01

    Hip-hop solutions of the 2N-body problem with equal masses are shown to exist using an analytic continuation argument. These solutions are close to planar regular 2N-gon relative equilibria with small vertical oscillations. For fixed N, an infinity of these solutions are three-dimensional choreographies, with all the bodies moving along the same closed curve in the inertial frame.

  4. Slopes, nearly constant loss, universality, and hopping rates for dispersive ionic conduction

    NASA Astrophysics Data System (ADS)

    Macdonald, J. Ross; Ahmad, Mohamad M.

    2007-01-01

    The title topics are investigated, discussed, and new insights provided by considering isothermal frequency response data for seven different materials having quite different conductivity spans and involving different electrode polarization effects and temperatures. These data sets were fitted using several different models, including the Kohlrausch-related K0 and K1 ones derived from stretched-exponential response in the temporal domain. The quasi-universal UN model, the K1 with its shape parameter, β1, fixed at 1/3, fitted most of the data very well, and its fits of such data were used to compare its predictions for hopping rate with those derived from fitting with the conventional 'universal dynamic response' Almond-West real-part-of-conductivity model. The K1-model theoretical hopping rate, involving the mean waiting time for a hop and derived from microscopic stochastic analysis, was roughly twice as large as the empirical Almond-West rate for most of the materials considered and should be used in place of it. Its use in a generalized Nernst-Einstein equation led to comparison of estimates of the concentration of fully dissociated mobile charge carriers in superionic PbSnF4 with earlier estimates of Ahmad using an Almond-West hopping rate value. Agreement with an independent structure-derived value was relatively poor. Fitting results obtained using the K0 model, for Na2SO4 data sets for two different polycrystalline material phases, and involving severely limited conductivity variation, were far superior to those obtained using the K1 model. The estimated values of the K0 shape parameter, β0, were close to 1/3 for both phases, strongly suggesting that the charge motion was one dimensional for each phase, even though they involved different crystalline structures.

  5. Locomotion in Extinct Giant Kangaroos: Were Sthenurines Hop-Less Monsters?

    PubMed Central

    Janis, Christine M.; Buttrill, Karalyn; Figueirido, Borja

    2014-01-01

    Sthenurine kangaroos (Marsupialia, Diprotodontia, Macropodoidea) were an extinct subfamily within the family Macropodidae (kangaroos and rat-kangaroos). These “short-faced browsers” first appeared in the middle Miocene, and radiated in the Plio-Pleistocene into a diversity of mostly large-bodied forms, more robust than extant forms in their build. The largest (Procoptodon goliah) had an estimated body mass of 240 kg, almost three times the size of the largest living kangaroos, and there is speculation whether a kangaroo of this size would be biomechanically capable of hopping locomotion. Previously described aspects of sthenurine anatomy (specialized forelimbs, rigid lumbar spine) would limit their ability to perform the characteristic kangaroo pentapedal walking (using the tail as a fifth limb), an essential gait at slower speeds as slow hopping is energetically unfeasible. Analysis of limb bone measurements of sthenurines in comparison with extant macropodoids shows a number of anatomical differences, especially in the large species. The scaling of long bone robusticity indicates that sthenurines are following the “normal” allometric trend for macropodoids, while the large extant kangaroos are relatively gracile. Other morphological differences are indicative of adaptations for a novel type of locomotor behavior in sthenurines: they lacked many specialized features for rapid hopping, and they also had anatomy indicative of supporting their body with an upright trunk (e.g., dorsally tipped ischiae), and of supporting their weight on one leg at a time (e.g., larger hips and knees, stabilized ankle joint). We propose that sthenurines adopted a bipedal striding gait (a gait occasionally observed in extant tree-kangaroos): in the smaller and earlier forms, this gait may have been employed as an alternative to pentapedal locomotion at slower speeds, while in the larger Pleistocene forms this gait may have enabled them to evolve to body sizes where hopping was

  6. Global minimization of gold clusters by combining neural network potentials and the basin-hopping method

    NASA Astrophysics Data System (ADS)

    Ouyang, Runhai; Xie, Yu; Jiang, De-En

    2015-09-01

    Neural network potentials trained by first-principles density functional theory total energies were applied to search for global minima of gold nanoclusters within the basin-hopping method. Using Au58 as an example, we found a new putative global minimum which has a core-shell structure of Au10@Au48 and C4 symmetry. This new structure of Au58 is 0.24 eV per formula more stable than the best previous model that has C1 symmetry. This work demonstrates that neural network potentials combined with the basin-hopping method could be very useful in global minimization for medium-sized metal clusters which might be computationally prohibitive for first principles density functional theory.Neural network potentials trained by first-principles density functional theory total energies were applied to search for global minima of gold nanoclusters within the basin-hopping method. Using Au58 as an example, we found a new putative global minimum which has a core-shell structure of Au10@Au48 and C4 symmetry. This new structure of Au58 is 0.24 eV per formula more stable than the best previous model that has C1 symmetry. This work demonstrates that neural network potentials combined with the basin-hopping method could be very useful in global minimization for medium-sized metal clusters which might be computationally prohibitive for first principles density functional theory. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03903g

  7. On the inclusion of the diagonal Born-Oppenheimer correction in surface hopping methods

    NASA Astrophysics Data System (ADS)

    Gherib, Rami; Ye, Liyuan; Ryabinkin, Ilya G.; Izmaylov, Artur F.

    2016-04-01

    The diagonal Born-Oppenheimer correction (DBOC) stems from the diagonal second derivative coupling term in the adiabatic representation, and it can have an arbitrary large magnitude when a gap between neighbouring Born-Oppenheimer (BO) potential energy surfaces (PESs) is closing. Nevertheless, DBOC is typically neglected in mixed quantum-classical methods of simulating nonadiabatic dynamics (e.g., fewest-switch surface hopping (FSSH) method). A straightforward addition of DBOC to BO PESs in the FSSH method, FSSH+D, has been shown to lead to numerically much inferior results for models containing conical intersections. More sophisticated variation of the DBOC inclusion, phase-space surface-hopping (PSSH) was more successful than FSSH+D but on model problems without conical intersections. This work comprehensively assesses the role of DBOC in nonadiabatic dynamics of two electronic state problems and the performance of FSSH, FSSH+D, and PSSH methods in variety of one- and two-dimensional models. Our results show that the inclusion of DBOC can enhance the accuracy of surface hopping simulations when two conditions are simultaneously satisfied: (1) nuclei have kinetic energy lower than DBOC and (2) PESs are not strongly nonadiabatically coupled. The inclusion of DBOC is detrimental in situations where its energy scale becomes very high or even diverges, because in these regions PESs are also very strongly coupled. In this case, the true quantum formalism heavily relies on an interplay between diagonal and off-diagonal nonadiabatic couplings while surface hopping approaches treat diagonal terms as PESs and off-diagonal ones stochastically.

  8. Magnetoconductance of CdSe in the hopping regime: The effect of quantum interference

    SciTech Connect

    Zhang, Y.; Dai, P.; Sarachik, M.P. )

    1992-04-15

    A magnetoconductance is observed for weakly insulating {ital n}-type CdSe, which, depending on the temperature of the measurement, is quadratic or approximately linear with field in small magnetic fields, and exhibits saturation as the field is increased. The crossovers from quadratic to linear behavior and to saturation occur at magnetic fields which are consistent with theoretical expectations for the effect of quantum interference in the hopping regime.

  9. Role of Plasmids in Lactobacillus brevis BSO 464 Hop Tolerance and Beer Spoilage

    PubMed Central

    Bergsveinson, Jordyn; Baecker, Nina; Pittet, Vanessa

    2014-01-01

    Specific isolates of lactic acid bacteria (LAB) can grow in the harsh beer environment, thus posing a threat to brew quality and the economic success of breweries worldwide. Plasmid-localized genes, such as horA, horC, and hitA, have been suggested to confer hop tolerance, a trait required for LAB survival in beer. The presence and expression of these genes among LAB, however, do not universally correlate with the ability to grow in beer. Genome sequencing of the virulent beer spoilage organism Lactobacillus brevis BSO 464 revealed the presence of eight plasmids, with plasmids 1, 2, and 3 containing horA, horC, and hitA, respectively. To investigate the roles that these and the other five plasmids play in L. brevis BSO 464 growth in beer, plasmid curing with novobiocin was used to derive 10 plasmid variants. Multiplex PCRs were utilized to determine the presence or absence of each plasmid, and how plasmid loss affected hop tolerance and growth in degassed (noncarbonated) beer was assessed. Loss of three of the eight plasmids was found to affect hop tolerance and growth in beer. Loss of plasmid 2 (horC and 28 other genes) had the most dramatic effect, with loss of plasmid 4 (120 genes) and plasmid 8 (47 genes) having significant, but smaller, impacts. These results support the contention that genes on mobile genetic elements are essential for bacterial growth in beer and that beer spoilage ability is not dependent solely on the three previously described hop tolerance genes or on the chromosome of a beer spoilage LAB isolate. PMID:25501474

  10. Locomotion in extinct giant kangaroos: were sthenurines hop-less monsters?

    PubMed

    Janis, Christine M; Buttrill, Karalyn; Figueirido, Borja

    2014-01-01

    Sthenurine kangaroos (Marsupialia, Diprotodontia, Macropodoidea) were an extinct subfamily within the family Macropodidae (kangaroos and rat-kangaroos). These "short-faced browsers" first appeared in the middle Miocene, and radiated in the Plio-Pleistocene into a diversity of mostly large-bodied forms, more robust than extant forms in their build. The largest (Procoptodon goliah) had an estimated body mass of 240 kg, almost three times the size of the largest living kangaroos, and there is speculation whether a kangaroo of this size would be biomechanically capable of hopping locomotion. Previously described aspects of sthenurine anatomy (specialized forelimbs, rigid lumbar spine) would limit their ability to perform the characteristic kangaroo pentapedal walking (using the tail as a fifth limb), an essential gait at slower speeds as slow hopping is energetically unfeasible. Analysis of limb bone measurements of sthenurines in comparison with extant macropodoids shows a number of anatomical differences, especially in the large species. The scaling of long bone robusticity indicates that sthenurines are following the "normal" allometric trend for macropodoids, while the large extant kangaroos are relatively gracile. Other morphological differences are indicative of adaptations for a novel type of locomotor behavior in sthenurines: they lacked many specialized features for rapid hopping, and they also had anatomy indicative of supporting their body with an upright trunk (e.g., dorsally tipped ischiae), and of supporting their weight on one leg at a time (e.g., larger hips and knees, stabilized ankle joint). We propose that sthenurines adopted a bipedal striding gait (a gait occasionally observed in extant tree-kangaroos): in the smaller and earlier forms, this gait may have been employed as an alternative to pentapedal locomotion at slower speeds, while in the larger Pleistocene forms this gait may have enabled them to evolve to body sizes where hopping was no longer

  11. Role of plasmids in Lactobacillus brevis BSO 464 hop tolerance and beer spoilage.

    PubMed

    Bergsveinson, Jordyn; Baecker, Nina; Pittet, Vanessa; Ziola, Barry

    2015-02-01

    Specific isolates of lactic acid bacteria (LAB) can grow in the harsh beer environment, thus posing a threat to brew quality and the economic success of breweries worldwide. Plasmid-localized genes, such as horA, horC, and hitA, have been suggested to confer hop tolerance, a trait required for LAB survival in beer. The presence and expression of these genes among LAB, however, do not universally correlate with the ability to grow in beer. Genome sequencing of the virulent beer spoilage organism Lactobacillus brevis BSO 464 revealed the presence of eight plasmids, with plasmids 1, 2, and 3 containing horA, horC, and hitA, respectively. To investigate the roles that these and the other five plasmids play in L. brevis BSO 464 growth in beer, plasmid curing with novobiocin was used to derive 10 plasmid variants. Multiplex PCRs were utilized to determine the presence or absence of each plasmid, and how plasmid loss affected hop tolerance and growth in degassed (noncarbonated) beer was assessed. Loss of three of the eight plasmids was found to affect hop tolerance and growth in beer. Loss of plasmid 2 (horC and 28 other genes) had the most dramatic effect, with loss of plasmid 4 (120 genes) and plasmid 8 (47 genes) having significant, but smaller, impacts. These results support the contention that genes on mobile genetic elements are essential for bacterial growth in beer and that beer spoilage ability is not dependent solely on the three previously described hop tolerance genes or on the chromosome of a beer spoilage LAB isolate. PMID:25501474

  12. Diacylglycerol Guides the Hopping of Clathrin-Coated Pits along Microtubules for Exo-Endocytosis Coupling.

    PubMed

    Yuan, Tianyi; Liu, Lin; Zhang, Yongdeng; Wei, Lisi; Zhao, Shiqun; Zheng, Xiaolu; Huang, Xiaoshuai; Boulanger, Jerome; Gueudry, Charles; Lu, Jingze; Xie, Lihan; Du, Wen; Zong, Weijian; Yang, Lu; Salamero, Jean; Liu, Yanmei; Chen, Liangyi

    2015-10-12

    Many receptor-mediated endocytic processes are mediated by constitutive budding of clathrin-coated pits (CCPs) at spatially randomized sites before slowly pinching off from the plasma membrane (60-100 s). In contrast, clathrin-mediated endocytosis (CME) coupled with regulated exocytosis in excitable cells occurs at peri-exocytic sites shortly after vesicle fusion (∼10 s). The molecular mechanism underlying this spatiotemporal coupling remains elusive. We show that coupled endocytosis makes use of pre-formed CCPs, which hop to nascent fusion sites nearby following vesicle exocytosis. A dynamic cortical microtubular network, anchored at the cell surface by the cytoplasmic linker-associated protein on microtubules and the LL5β/ELKS complex on the plasma membrane, provides the track for CCP hopping. Local diacylglycerol gradients generated upon exocytosis guide the direction of hopping. Overall, the CCP-cytoskeleton-lipid interaction demonstrated here mediates exocytosis-coupled fast recycling of both plasma membrane and vesicular proteins, and it is required for the sustained exocytosis during repetitive stimulations. PMID:26439397

  13. Molecular mechanisms behind the antimicrobial activity of hop iso-α-acids in Lactobacillus brevis.

    PubMed

    Schurr, Benjamin C; Hahne, Hannes; Kuster, Bernhard; Behr, Jürgen; Vogel, Rudi F

    2015-04-01

    The main bittering component in beer, hop iso-α-acids, have been characterised as weak acids, which act as ionophores impairing microbial cells' function under acidic conditions as present in beer. Besides medium pH, divalent cations play a central role regarding the efficacy of the antimicrobial effect. The iso-α-acids' non-bitter derivatives humulinic acids can be found in isomerised hop extracts and can be generated during hop storage. Therefore, they have been under investigation concerning their influence on beer sensory properties. This study sketches the molecular mechanism behind iso-α-acids' antimicrobial activity in Lactobacillus (L.) brevis regarding their ionophore activity versus the dependence of the inhibitory potential on manganese binding, and suggests humulinic acids as novel tasteless food preservatives. We designed and synthesised chemically modified iso-α-acids to enhance the basic understanding of the molecular mechanism of antimicrobial iso-α-acids. It could be observed that a manganese-binding dependent transmembrane redox reaction (oxidative stress) plays a crucial role in inhibition. Privation of an acidic hydroxyl group neither erased ionophore activity, nor did it entirely abolish antimicrobial activity. Humulinic acids proved to be highly inhibitory, even outperforming iso-α-acids. PMID:25475328

  14. Time-resolved Tomographic PIV Measurements of Water Flea Hopping: Body Size Comparison

    NASA Astrophysics Data System (ADS)

    Skipper, A. N.; Murphy, D. W.; Webster, D. R.; Yen, J.

    2014-11-01

    The flow field of the freshwater crustacean Daphnia magna is quantified with time-resolved tomographic PIV. In the current work, we compare body kinematics and flow disturbance between organisms of small (body length = 1.8 mm) versus medium (2.3 mm) versus large (2.65 mm) size. These plankters are equipped with a pair of antennae that are biramous such that the protopodite splits or branches into an exopodite and an endopodite. They beat the antennae pair synchronously to impulsively propel themselves, or `hop,' through the water. The stroke cycle of Daphnia magna is roughly 80 ms in duration and this period is evenly split between the power and recovery strokes. A typical hop carries the daphniid one body length forward and is followed by a period of sinking. Unlike copepod escape motion, no body vortex is observed in front of the animal. Rather, the flow induced by each antennae consists of a viscous vortex ring that demonstrates a slow decay. The time-record of velocity (peak of 40 mm/s for the medium specimen) and hop acceleration (1.8 m/s2 for the medium specimen) are compared, as well as the strength, size, and decay of the induced viscous vortex rings. The viscous vortex ring analysis will be presented in the context of a double Stokeslet model consisting of two impulsively applied point forces separated by the animal width.

  15. A very general rate expression for charge hopping in semiconducting polymers.

    PubMed

    Fornari, Rocco P; Aragó, Juan; Troisi, Alessandro

    2015-05-14

    We propose an expression of the hopping rate between localized states in semiconducting disordered polymers that contain the most used rates in the literature as special cases. We stress that these rates cannot be obtained directly from electron transfer rate theories as it is not possible to define diabatic localized states if the localization is caused by disorder, as in most polymers, rather than nuclear polarization effects. After defining the separate classes of accepting and inducing nuclear modes in the system, we obtain a general expression of the hopping rate. We show that, under the appropriate limits, this expression reduces to (i) a single-phonon rate expression or (ii) the Miller-Abrahams rate or (iii) a multi-phonon expression. The description of these limits from a more general expression is useful to interpolate between them, to validate the assumptions of each limiting case, and to define the simplest rate expression that still captures the main features of the charge transport. When the rate expression is fed with a range of realistic parameters the deviation from the Miller-Abrahams rate is large or extremely large, especially for hopping toward lower energy states, due to the energy gap law. PMID:25978881

  16. Crossover from facilitation to hopping in a colloidal glass-former

    NASA Astrophysics Data System (ADS)

    Gokhale, Shreyas; Ganapathy, Rajesh; Nagamanasa, K. Hima; Sood, A. K.

    Despite extensive research, it remains to be established whether glass formation is a fundamentally thermodynamic or dynamic phenomenon. In particular, it is not yet clear whether structural relaxation is dominated by the correlated motion of localized excitations, as postulated by the dynamical facilitation (DF) theory, or by the collective hopping of groups of particles, as envisioned by various thermodynamic approaches. Here, by analyzing data from experiments on dense colloidal suspensions, we critically compare the role of facilitation and hopping in governing structural relaxation in glass-forming liquids. In particular, we investigate the spatial organization of localized excitations within clusters of most mobile particles as well as their partitioning into shell-like and core-like regions. Our study reveals the existence of a dynamical crossover from a facilitation dominated regime at low area fractions to one dominated by collective hopping close to the glass transition. Our findings strongly suggest that glass formation is thermodynamic in origin. Currently at the Center for Soft and Living Matter, UNIST, Republic of Korea.

  17. The Number of Trials Required to Obtain a Representative Movement Pattern During a Hurdle Hop Exercise.

    PubMed

    Gore, Shane J; Marshall, Brendan M; Franklyn-Miller, Andrew D; Falvey, Eanna C; Moran, Kieran A

    2016-06-01

    When reporting a subject's mean movement pattern, it is important to ensure that reported values are representative of the subject's typical movement. While previous studies have used the mean of 3 trials, scientific justification of this number is lacking. One approach is to determine statistically how many trials are required to achieve a representative mean. This study compared 4 methods of calculating the number of trials required in a hopping movement to achieve a representative mean. Fifteen males completed 15 trials of a lateral hurdle hop. Range of motion at the trunk, pelvis, hip, knee, and ankle, in addition to peak moments for the latter 3 joints were examined. The number of trials required was computed using a peak intraclass correlation coefficient method, sequential analysis with a bandwidth of acceptable variance in the mean, and a novel method based on the standard error of measurement (SEMind). The number of trials required across all variables ranged from 2 to 12 depending on method, joint, and anatomical plane. The authors advocate the SEMind method as it demonstrated fewer limitations than the other methods. Using the SEMind, the required number of trials for a representative mean during the lateral hurdle hop is 6. PMID:26667614

  18. Dynamic Task Allocation in Multi-Hop Multimedia Wireless Sensor Networks with Low Mobility

    PubMed Central

    Jin, Yichao; Vural, Serdar; Gluhak, Alexander; Moessner, Klaus

    2013-01-01

    This paper presents a task allocation-oriented framework to enable efficient in-network processing and cost-effective multi-hop resource sharing for dynamic multi-hop multimedia wireless sensor networks with low node mobility, e.g., pedestrian speeds. The proposed system incorporates a fast task reallocation algorithm to quickly recover from possible network service disruptions, such as node or link failures. An evolutional self-learning mechanism based on a genetic algorithm continuously adapts the system parameters in order to meet the desired application delay requirements, while also achieving a sufficiently long network lifetime. Since the algorithm runtime incurs considerable time delay while updating task assignments, we introduce an adaptive window size to limit the delay periods and ensure an up-to-date solution based on node mobility patterns and device processing capabilities. To the best of our knowledge, this is the first study that yields multi-objective task allocation in a mobile multi-hop wireless environment under dynamic conditions. Simulations are performed in various settings, and the results show considerable performance improvement in extending network lifetime compared to heuristic mechanisms. Furthermore, the proposed framework provides noticeable reduction in the frequency of missing application deadlines. PMID:24135992

  19. An Energy Efficient MAC Protocol for Multi-Hop Swallowable Body Sensor Networks

    PubMed Central

    Lin, Lin; Yang, Chengfeng; Wong, Kai Juan; Yan, Hao; Shen, Junwen; Phee, Soo Jay

    2014-01-01

    Swallowable body sensor networks (BSNs) are composed of sensors which are swallowed by patients and send the collected data to the outside coordinator. These sensors are energy constraint and the batteries are difficult to be replaced. The medium access control (MAC) protocol plays an important role in energy management. This paper investigates an energy efficient MAC protocol design for swallowable BSNs. Multi-hop communication is analyzed and proved more energy efficient than single-hop communication within the human body when the circuitry power is low. Based on this result, a centrally controlled time slotting schedule is proposed. The major workload is shifted from the sensors to the coordinator. The coordinator collects the path-loss map and calculates the schedules, including routing, slot assignment and transmission power. Sensor nodes follow the schedules to send data in a multi-hop way. The proposed protocol is compared with the IEEE 802.15.6 protocol in terms of energy consumption. The results show that it is more energy efficient than IEEE 802.15.6 for swallowable BSN scenarios. PMID:25330049

  20. Hop (Humulus lupulus L.) response mechanisms in drought stress: Proteomic analysis with physiology.

    PubMed

    Kolenc, Zala; Vodnik, Dominik; Mandelc, Stanislav; Javornik, Branka; Kastelec, Damijana; Čerenak, Andreja

    2016-08-01

    Drought is one of the major environmental devastating stressors that impair the growth and productivity of crop plants. Despite the relevance of drought stress, changes in physiology and resistance mechanisms are not completely understood for certain crops, including hop (Humulus lupulus L.). In this research the drought response of hop was studied using a conventional physiological approach (gas exchange techniques, fluorescence, relative water content measurements) and proteomic analysis (2D-DIGE). Plants of two cultivars (Aurora and Savinjski golding) were exposed to progressive drought in a pot experiment and analysed at different stress stages (mild, moderate and severe). Measurements of relative water content revealed a hydrostable water balance of hop. Photosynthesis was decreased due to stomatal and non-stomatal limitation to the same extent in both cultivars. Of 28 identified differentially abundant proteins, the majority were down regulated and included in photosynthetic (41%) and sugar metabolism (33%). Fifteen % of identified proteins were classified into the nitrogen metabolism, 4% were related to a ROS related pathway and 7% to other functions. PMID:27085598

  1. Stretch reflex improves rolling stability during hopping of a decerebrate biped system.

    PubMed

    Rosendo, Andre; Liu, Xiangxiao; Shimizu, Masahiro; Hosoda, Koh

    2015-01-01

    When humans hop, attitude recovery can be observed in both the sagittal and frontal planes. While it is agreed that the brain plays an important role in leg placement, the role of low-level feedback (the stretch reflex) on frontal plane stabilization remains unclear. Seeking to better understand the contribution of the soleus stretch reflex to rolling stability, we performed experiments on a biomimetic humanoid hopping robot. Various reflex responses to touching the floor, ranging from no response to long muscle activations, were examined, and the effect of a delay upon touching the floor was also examined. We found that the stretch reflex brought the system closer to stable, straight hopping. The presence of a delay did not affect the results; both the cases with and without a delay outperformed the case without a reflex response. The results of this study highlight the importance of low-level control in locomotion for which body stabilization does not require higher-level signals. PMID:25599138

  2. The variability of hop latent viroid as induced upon heat treatment.

    PubMed

    Matousek, J; Patzak, J; Orctová, L; Schubert, J; Vrba, L; Steger, G; Riesner, D

    2001-09-01

    We have previously shown that heat treatment of hop plants infected by hop latent viroid (HLVd) reduces viroid levels. Here we investigate whether such heat treatment leads to the accumulation of sequence variability in HLVd. We observed a negligible level of mutated variants in HLVd under standard cultivation conditions. In contrast, the heat treatment of hop led to HLVd degradation and, simultaneously, to a significant increase in sequence variations, as judged from temperature gradient-gel electrophoresis analysis and cDNA library screening by DNA heteroduplex analysis. Thirty-one cDNA clones (9.8%) were identified as deviating forms. Sequencing showed mostly the presence of quadruple and triple mutants, suggesting an accumulation of mutations in HLVd during successive replication cycles. Sixty-nine percent of base changes were localised in the left half and 31% in the right half of the secondary structure proposed for this viroid. No mutations were found in the central part of the upper conserved region. A "hot spot" region was identified in a domain known as a "pathogenicity domain" in the group representative, potato spindle tuber viroid. Most mutations are predicted to destabilise HLVd secondary structure. All mutated cDNAs, however, were infectious and evolved into complex progeny populations containing molecular variants maintained at low levels. PMID:11531412

  3. Image Transfer Frequency Division Multiplex Multi-Hop Network Using IEEE 802.15.4

    NASA Astrophysics Data System (ADS)

    Inui, Kazuhiro; Sugiura, Akihiko; Kobayashi, Hideyuki

    Recently, the wireless sensor network where advanced sensing, and image recognition and a network were connected attracts attention. In this research, the multi-hop wireless sensor network which carries out sensing of the image which used IEEE 802.15.4 ZigBee is built. In the multi-hop network, two or more sets of terminals may be communicating within 1 hop using the same frequency band. In that case, communicative delay occurs by access control (CSMA/CA) of IEEE 802.15.4. In order to solve this problem, in this research, proposal of the image transfer network which applied the Frequency Division Multiplex system to IEEE 802.15.4, and construction were performed. In order to show the usefulness of this proposal system, image transmission by the conventional system and a proposal system was performed, and transmission time was measured. When a proposal system was applied, improvement in a throughput has been confirmed as compared with the conventional system. Furthermore, improvement in a throughput was confirmed by performing a channel setup which avoided the channel currently used by wireless LAN. Moreover, it confirmed that a proposal system improved about 25 [msec] faster than the conventional system by the experiment of the picture transmission by communication of IEEE 802.15.4.

  4. Gold Digger or Video Girl: the salience of an emerging hip-hop sexual script.

    PubMed

    Ross, Jasmine N; Coleman, Nicole M

    2011-02-01

    Concerns have been expressed in the common discourse and scholarly literature about the negative influence of Hip-Hop on its young listeners' ideas about sex and sexuality. Most of the scholarly literature has focused on the impact of this urban, Black media on young African American girls' sexual self-concept and behaviours. In response to this discourse, Stephens and Phillips (2003) proposed a Hip-Hop sexual scripting model that theorises about specific sexual scripts for young African American women. Their model includes eight different sexual scripts including the Gold Digger script. The present study proposes a ninth emerging script - the Video Girl. Participants were 18 female African American college students, between the ages of 18 and 30 years old from a large urban public university in the Southwest USA. Using q-methodology the present study found support for the existence of a Video Girl script. In addition, the data indicates that this script is distinct but closely related to Stephens and Phillips' Gold Digger script. These findings support their theory by suggesting that Hip-Hop sexual scripts are salient and hold real meaning for this sample. PMID:20972917

  5. Interplay of electron hopping and bounded diffusion during charge transport in redox polymer electrodes.

    PubMed

    Akhoury, Abhinav; Bromberg, Lev; Hatton, T Alan

    2013-01-10

    Redox polymer electrodes (RPEs) have been prepared both by attachment of random copolymers of hydroxybutyl methacrylate and vinylferrocene (poly(HBMA-co-VF)) to carbon substrates by grafting either "to" or "from" the substrate surfaces, and by impregnation of porous carbon substrates with redox polymer gels of similar composition. An observed linear dependence of peak current on the square root of the applied voltage scan rate in cyclic voltammetry (CV) led to the conclusion that the rate controlling step in the redox process was the diffusive transfer of electrons through the redox polymer layer. The variation in the peak current with increasing concentration of the redox species in the polymer indicated that the electron transport transitioned from bounded diffusion to electron hopping. A modified form of the Blauch-Saveant equation for apparent diffusivity of electrons through a polymer film indicated that bounded diffusion was the dominant mechanism of electron transport in RPEs with un-cross-linked polymer chains at low concentrations of the redox species, but, as the concentration of the redox species increased, electron hopping became more dominant, and was the primary mode of electron diffusion above a certain concentration level of redox species. In the cross-linked polymer gels, bounded diffusion was limited because of the restricted mobility of the polymer chains. Electron hopping was the primary mode of electron diffusion in such systems at all concentrations of the redox species. PMID:23137318

  6. Discovery of Highly Potent and Selective Inhibitors of Neuronal Nitric Oxide Synthase by Fragment Hopping

    PubMed Central

    Ji, Haitao; Li, Huiying; Martásek, Pavel; Roman, Linda J.; Poulos, Thomas L.; Silverman, Richard B.

    2009-01-01

    Selective inhibition of neuronal nitric oxide synthase (nNOS) has been shown to prevent brain injury and is important for the treatment of various neurodegenerative disorders. This study shows that not only greater inhibitory potency and isozyme selectivity, but more drug-like properties can be achieved by fragment hopping. Based on the structure of lead molecule 6, fragment hopping effectively extracted the minimal pharmacophoric elements in the active site of nNOS for ligand hydrophobic and steric interactions and generated appropriate lipophilic fragments for lead optimization. More potent and selective inhibitors with better drug-like properties were obtained within the design of 20 derivatives (compounds 7-26). Our structure-based inhibitor design for nNOS and SAR analysis reveal the robustness and efficiency of fragment hopping in lead discovery and structural optimization, which implicates a broad application of this approach to many other therapeutic targets for which known drug-like small-molecule modulators are still limited. PMID:19125620

  7. A very general rate expression for charge hopping in semiconducting polymers

    SciTech Connect

    Fornari, Rocco P.; Aragó, Juan; Troisi, Alessandro

    2015-05-14

    We propose an expression of the hopping rate between localized states in semiconducting disordered polymers that contain the most used rates in the literature as special cases. We stress that these rates cannot be obtained directly from electron transfer rate theories as it is not possible to define diabatic localized states if the localization is caused by disorder, as in most polymers, rather than nuclear polarization effects. After defining the separate classes of accepting and inducing nuclear modes in the system, we obtain a general expression of the hopping rate. We show that, under the appropriate limits, this expression reduces to (i) a single-phonon rate expression or (ii) the Miller-Abrahams rate or (iii) a multi-phonon expression. The description of these limits from a more general expression is useful to interpolate between them, to validate the assumptions of each limiting case, and to define the simplest rate expression that still captures the main features of the charge transport. When the rate expression is fed with a range of realistic parameters the deviation from the Miller-Abrahams rate is large or extremely large, especially for hopping toward lower energy states, due to the energy gap law.

  8. Appraisal of Surface Hopping as a Tool for Modeling Condensed Phase Linear Absorption Spectra.

    PubMed

    Petit, Andrew S; Subotnik, Joseph E

    2015-09-01

    Whereas surface hopping is usually used to study populations and mean-field dynamics to study coherences, in two recent papers, we described a procedure for calculating dipole-dipole correlation functions (and therefore absorption spectra) directly from ensembles of surface hopping trajectories. We previously applied this method to a handful of one-dimensional model problems intended to mimic the gas phase. In this article, we now benchmark this new procedure on a set of multidimensional model problems intended to mimic the condensed phase and compare our results against other standard semiclassical methods. By comparison, we demonstrate that methods that include only dynamical information from one PES (the standard Kubo approaches) exhibit large discrepancies with the results of exact quantum dynamics. Furthermore, for model problems with nonadiabatic excited state dynamics but no quantized vibrational structure in the spectra, our surface hopping approach performs comparably to using Ehrenfest dynamics to calculate the electronic coherences. That being said, however, when quantized vibrational structures are present in the spectra but the electronic states are uncoupled, performing the dynamics on the mean PES still outperforms our present method. These benchmark results should influence future studies that use ensembles of independent semiclassical trajectories to model linear as well as multidimensional spectra in the condensed phase. PMID:26575927

  9. An energy efficient MAC protocol for multi-hop swallowable body sensor networks.

    PubMed

    Lin, Lin; Yang, Chengfeng; Wong, Kai Juan; Yan, Hao; Shen, Junwen; Phee, Soo Jay

    2014-01-01

    Swallowable body sensor networks (BSNs) are composed of sensors which are swallowed by patients and send the collected data to the outside coordinator. These sensors are energy constraint and the batteries are difficult to be replaced. The medium access control (MAC) protocol plays an important role in energy management. This paper investigates an energy efficient MAC protocol design for swallowable BSNs. Multi-hop communication is analyzed and proved more energy efficient than single-hop communication within the human body when the circuitry power is low. Based on this result, a centrally controlled time slotting schedule is proposed. The major workload is shifted from the sensors to the coordinator. The coordinator collects the path-loss map and calculates the schedules, including routing, slot assignment and transmission power. Sensor nodes follow the schedules to send data in a multi-hop way. The proposed protocol is compared with the IEEE 802.15.6 protocol in terms of energy consumption. The results show that it is more energy efficient than IEEE 802.15.6 for swallowable BSN scenarios. PMID:25330049

  10. Low-coverage surface diffusion in complex periodic energy landscapes. II. Analytical solution for systems with asymmetric hops

    NASA Astrophysics Data System (ADS)

    Gosálvez, Miguel A.; Otrokov, Mikhail M.; Ferrando, Nestor; Ryabishchenkova, Anastasia G.; Ayuela, Andres; Echenique, Pedro M.; Chulkov, Evgueni V.

    2016-05-01

    This is part II in a series of two papers that introduce a general expression for the tracer diffusivity in complex, periodic energy landscapes with M distinct hop rates in one-, two-, and three-dimensional diluted systems (low coverage, single-tracer limit). While Part I [Gosálvez et al., Phys. Rev. B 93, 075429 (2016), 10.1103/PhysRevB.93.075429] focuses on the analysis of diffusion in systems where the end sites of the hops are located symmetrically with respect to the hop origins (symmetric hops), as encountered in many ideal surfaces and bulk materials, this report (Part II) presents a more general approach to determining the tracer diffusivity in systems where the end sites can be located asymmetrically with respect to the hop origins (asymmetric hops), as observed in reconstructed and/or chemically modified surfaces and/or bulk materials. The obtained diffusivity formulas for numerous systems are validated against kinetic Monte Carlo simulations and previously reported analytical expressions based on the continuous-time random walk (CTRW) method. The proposed method corrects some of the CTRW formulas and provides new expressions for difficult cases that have not been solved earlier. This demonstrates the ability of the proposed formalism to describe tracer diffusion.

  11. Structural Identification of the Vps18 β-Propeller Reveals a Critical Role in the HOPS Complex Stability and Function*

    PubMed Central

    Behrmann, Heide; Lürick, Anna; Kuhlee, Anne; Balderhaar, Henning Kleine; Bröcker, Cornelia; Kümmel, Daniel; Engelbrecht-Vandré, Siegfried; Gohlke, Ulrich; Raunser, Stefan; Heinemann, Udo; Ungermann, Christian

    2014-01-01

    Membrane fusion at the vacuole, the lysosome equivalent in yeast, requires the HOPS tethering complex, which is recruited by the Rab7 GTPase Ypt7. HOPS provides a template for the assembly of SNAREs and thus likely confers fusion at a distinct position on vacuoles. Five of the six subunits in HOPS have a similar domain prediction with strong similarity to COPII subunits and nuclear porins. Here, we show that Vps18 indeed has a seven-bladed β-propeller as its N-terminal domain by revealing its structure at 2.14 Å. The Vps18 N-terminal domain can interact with the N-terminal part of Vps11 and also binds to lipids. Although deletion of the Vps18 N-terminal domain does not preclude HOPS assembly, as revealed by negative stain electron microscopy, the complex is instable and cannot support membrane fusion in vitro. We thus conclude that the β-propeller of Vps18 is required for HOPS stability and function and that it can serve as a starting point for further structural analyses of the HOPS tethering complex. PMID:25324549

  12. Musculoskeletal modelling deconstructs the paradoxical effects of elastic ankle exoskeletons on plantar-flexor mechanics and energetics during hopping

    PubMed Central

    Farris, Dominic James; Hicks, Jennifer L.; Delp, Scott L.; Sawicki, Gregory S.

    2014-01-01

    Experiments have shown that elastic ankle exoskeletons can be used to reduce ankle joint and plantar-flexor muscle loading when hopping in place and, in turn, reduce metabolic energy consumption. However, recent experimental work has shown that such exoskeletons cause less favourable soleus (SO) muscle–tendon mechanics than is observed during normal hopping, which might limit the capacity of the exoskeleton to reduce energy consumption. To directly link plantar-flexor mechanics and energy consumption when hopping in exoskeletons, we used a musculoskeletal model of the human leg and a model of muscle energetics in simulations of muscle–tendon dynamics during hopping with and without elastic ankle exoskeletons. Simulations were driven by experimental electromyograms, joint kinematics and exoskeleton torque taken from previously published data. The data were from seven males who hopped at 2.5 Hz with and without elastic ankle exoskeletons. The energetics model showed that the total rate of metabolic energy consumption by ankle muscles was not significantly reduced by an ankle exoskeleton. This was despite large reductions in plantar-flexor force production (40–50%). The lack of larger metabolic reductions with exoskeletons was attributed to increases in plantar-flexor muscle fibre velocities and a shift to less favourable muscle fibre lengths during active force production. This limited the capacity for plantar-flexors to reduce activation and energy consumption when hopping with exoskeleton assistance. PMID:25278469

  13. Significance of ligand interactions involving Hop2-Mnd1 and the RAD51 and DMC1 recombinases in homologous DNA repair and XX ovarian dysgenesis.

    PubMed

    Zhao, Weixing; Sung, Patrick

    2015-04-30

    The evolutionarily conserved Hop2-Mnd1 complex is a key cofactor for the meiosis-specific recombinase Dmc1. However, emerging evidence has revealed that Hop2-Mnd1 is expressed in somatic tissues, primary human fibroblasts and cell lines, and that it functions in conjunction with the Rad51 recombinase to repair damaged telomeres via the alternate lengthening of telomeres mechanism. Here, we reveal how distinct DNA-binding activities of Hop2-Mnd1 mediate the stabilization of the RAD51-ssDNA presynaptic filament or stimulate the homologous DNA pairing reaction. We have also endeavored to define the interface that governs the assembly of the higher order complex of Hop2-Mnd1 with RAD51. Unexpectedly, we find that ATP enhances the interaction between Hop2-Mnd1 and RAD51, and that both Hop2 and Mnd1 are involved in RAD51 interaction via their C-terminal regions. Importantly, mutations introduced into these Hop2 and Mnd1 domains, including the HOP2 p.del201Glu mutation present in a patient of XX ovarian dysgenesis, diminish the association and functional synergy of Hop2-Mnd1 with both RAD51 and DMC1. Our findings help delineate the intricate manner in which Hop2-Mnd1 engages and functions with RAD51 and DMC1 in mammalian cells and speak to the possible cause of XX ovarian dysgenesis. PMID:25820426

  14. Analysis and Relative Evaluation of Connectivity of a Mobile Multi-Hop Network

    NASA Astrophysics Data System (ADS)

    Nakano, Keisuke; Miyakita, Kazuyuki; Sengoku, Masakazu; Shinoda, Shoji

    In mobile multi-hop networks, a source node S and a destination node D sometimes encounter a situation where there is no multi-hop path between them when a message M, destined for D, arrives at S. In this situation, we cannot send M from S to D immediately; however, we can deliver M to D after waiting some time with the help of two capabilities of mobility. One of the capabilities is to construct a connected multi-hop path by changing the topology of the network during the waiting time (Capability 1), and the other is to move M closer to D during the waiting time (Capability 2). In this paper, we consider three methods to deliver M from S to D by using these capabilities in different ways. Method 1 uses Capability 1 and sends M from S to D after waiting until a connected multi-hop path appears between S and D. Method 2 uses Capability 2 and delivers M to D by allowing a mobile node to carry M from S to D. Method 3 is a combination of Methods 1 and 2 and minimizes the waiting time. We evaluate and compare these three methods in terms of the mean waiting time, from the time when M arrives at S to the time when D starts receiving M, as a new approach to connectivity evaluation. We consider a one-dimensional mobile multi-hop network consisting of mobile nodes flowing in opposite directions along a street. First, we derive some approximate equations and propose an estimation method to compute the mean waiting time of Method 1. Second, we theoretically analyze the mean waiting time of Method 2, and compute a lower bound of that of Method 3. By comparing the three methods under the same assumptions using results of the analyses and some simulation results, we show relations between the mean waiting times of these methods and show how Capabilities 1 and 2 differently affect the mean waiting time.

  15. Investigation of the anxiolytic effects of xanthohumol, a component of humulus lupulus (Hops), in the male Sprague-Dawley rat.

    PubMed

    Ceremuga, Thomas E; Johnson, Lori A; Adams-Henderson, Jamilia M; McCall, Suzanne; Johnson, Don

    2013-06-01

    The purpose of this study was to investigate the anxiolytic effects of xanthohumol, a component of Humulus lupulus (hops), and its potential interaction with the benzodiazepine binding site on the y-aminobutyric acid (GABAA) receptor in the male Sprague-Dawley rat. This was a prospective, randomized, between-subjects experimental study. Fifty-five rats were assigned to 1 Sof 5 groups with 11 rats per group: control (vehicle), xanthohumol, midazolam, midazolam with xanthohumol, and flumazenil with xanthohumol. In this study the elevated plus maze measured the behavioral components of anxiety and motor movements. A 2-tailed multivariate analysis of variance and least significant difference post hoc test was used to determine if a significant difference existed. Our data suggest that xanthohumol does not produce anxiolysis by modulation of the GABAA receptor; however, there may be a possible interaction between xanthohumol and midazolam, or xanthohumol may influence the modulation of another neurotransmitter site in the central nervous system. Alone, xanthohumol does not show significant modulation of the benzodiazepine receptor. Additional research should investigate if xanthohumol acts as a benzodiazepine GABAA partial agonist or antagonist or if it modulates another neurotransmitter system in the central nervous system. PMID:23923669

  16. A new neuro-FDS definition for indirect adaptive control of unknown nonlinear systems using a method of parameter hopping.

    PubMed

    Boutalis, Yiannis; Theodoridis, Dimitris C; Christodoulou, Manolis A

    2009-04-01

    The indirect adaptive regulation of unknown nonlinear dynamical systems is considered in this paper. The method is based on a new neuro-fuzzy dynamical system (neuro-FDS) definition, which uses the concept of adaptive fuzzy systems (AFSs) operating in conjunction with high-order neural network functions (FHONNFs). Since the plant is considered unknown, we first propose its approximation by a special form of an FDS and then the fuzzy rules are approximated by appropriate HONNFs. Thus, the identification scheme leads up to a recurrent high-order neural network (RHONN), which however takes into account the fuzzy output partitions of the initial FDS. The proposed scheme does not require a priori experts' information on the number and type of input variable membership functions making it less vulnerable to initial design assumptions. Once the system is identified around an operation point, it is regulated to zero adaptively. Weight updating laws for the involved HONNFs are provided, which guarantee that both the identification error and the system states reach zero exponentially fast, while keeping all signals in the closed loop bounded. The existence of the control signal is always assured by introducing a novel method of parameter hopping, which is incorporated in the weight updating law. Simulations illustrate the potency of the method and comparisons with conventional approaches on benchmarking systems are given. Also, the applicability of the method is tested on a direct current (dc) motor system where it is shown that by following the proposed procedure one can obtain asymptotic regulation. PMID:19273046

  17. "Makin' Somethin' Outta Little-to-Nufin'': Racism, Revision and Rotating Records--The Hip-Hop DJ in Composition Praxis

    ERIC Educational Resources Information Center

    Craig, Todd

    2015-01-01

    Prompted by a moment in the classroom in which the DJ becomes integral for the writing instructor, this article looks at how the hip-hop DJ and hip-hop DJ/Producer become the intrinsic examples for first-year college writing students to think about how they conduct revision in their writing. After a review of two seminal hip-hop books and other…

  18. Effects of xanthohumol-rich extract from the hop on fatty acid metabolism in rats fed a high-fat diet.

    PubMed

    Yui, Kazuki; Kiyofuji, Ayane; Osada, Kyoichi

    2014-01-01

    Xanthohumol is the major prenylated flavonoid of female inflorescences of the hop plant (Humulus lupulus L.) and is a hydrophobic flavonoid. We examined the effects of dietary xanthohumol-rich hop extract in obese rats that was induced by feeding a high-fat diet. Dietary xanthohumol-rich hop extract significantly lowered the body weight gain of these rats compared to rats fed a high-fat diet without the extract. The increase of body weight, liver weight, and triacylglycerol levels in the plasma and liver of the rats fed a high-fat diet was ameliorated by dietary xanthohumol-rich hop extract. Dietary xanthohumol-rich hop extract tended to reduce hepatic fatty acid synthesis through the reduction of hepatic SREBP1c mRNA expression in the rats fed a high-fat diet. The excreted of triacylglycerol into feces also was promoted by dietary xanthohumol-rich hop extract. Plasma adiponectin levels in the rats fed a high-fat diet also tended to be elevated by dietary xanthohumol-rich hop extract. Thus, xanthohumol-rich hop extract may inhibit the increase of body weight, liver weight, and triacylglycerol in the plasma and liver induced by feeding high-fat diet through the regulation of hepatic fatty acid metabolism and inhibition of intestinal fat absorption. Therefore, xanthohumol-rich hop extract may exert preventive function on the increase of body weight and tissue triacylglycerol levels by overnutrition. PMID:24420065

  19. Diagnostic real-time RT-PCR for the simultaneous detection of Citrus exocortis viroid and Hop stunt viroid.

    PubMed

    Papayiannis, Lambros C

    2014-02-01

    Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd) are two important viroids known to infect several plant species worldwide. In this study, a real-time reverse transcription (RT) TaqMan polymerase chain reaction (PCR) assay was developed and optimized for the simultaneous detection of CEVd and HSVd. The assay's analytical and diagnostic sensitivity and specificity were evaluated using reference isolates. Two different RNA extraction methods and one rapid crude template preparation procedure were compared in terms of extraction purity and efficiency for PCR applications. Extraction method Q included a commercially available kit, whereas method C was a modified chloroform-phase extraction in house protocol. Procedure S involved blotting the sap extract on a positively charged nylon membrane and elution. The multiplex RT-TaqMan PCR assay successfully discriminated the two viroid species from all reference samples and its recorded diagnostic sensitivity (Dse) and specificity (Dsp) was 100%. On the contrary, in conventional RT-PCR tests, the overall Dse and Dsp were lower and estimated at 94 and 95% for CEVd, and 97 and 98% for HSVd, respectively. In a direct comparison, the developed assay presented 1000-fold more analytical sensitivity. Spectrophotometric results showed that RNA extraction methods Q and C, yielded the purest RNA, and gave the lowest mean Ct values. Alternative template preparation method S resulted in Ct values statistically similar to those obtained with methods Q to C when tested by RT-TaqMan PCR. The developed assay, using crude template preparation S, allows the simple, accurate and cost-effective testing of a large number of plant samples, and can be applied in surveys and certification schemes. PMID:24252553

  20. Transport of hop bitter acids across intestinal Caco-2 cell monolayers.

    PubMed

    Cattoor, Ko; Bracke, Marc; Deforce, Dieter; De Keukeleire, Denis; Heyerick, Arne

    2010-04-14

    Several health-beneficial properties of hop bitter acids have been reported (inhibition of bone resorption and anticarcinogenic and anti-inflammatory activities); however, scientific data on the bioavailability of these compounds are lacking. As a first approach to study the bioavailability, the epithelial transport of hop alpha- and beta-acids across Caco-2 monolayers was investigated. Hop acids were added either to the apical or to the basolateral chamber and, at various time points, amounts transported to the receiving compartment were determined. The monolayer integrity control was performed by using marker compounds (atenolol and propranolol), transepithelial electrical resistance (TEER) measurement, and determination of the fluorescein efflux. The TEER and fluorescein efflux confirmed the preservation of the monolayer integrity. The membrane permeability of the alpha-acids (apparent permeability coefficients for apical to basolateral transport (P(appAB)) ranged from 14 x 10(-6) to 41 x 10(-6) cm/s) was determined to be substantially higher than that of the beta-acids (P(appAB) values ranging from 0.9 x 10(-6) to 2.1 x 10(-6) cm/s). Notably, the beta-acids exhibited significantly different bidirectional P(app) values with efflux ratios around 10. The involvement of carrier-mediated transport for beta-acids (active efflux pathway by P-gp, BCRP, and/or MRP-2 type efflux pumps) could be confirmed by transport experiments with specific inhibitors (verapamil and indomethacin). It appears that alpha-acids are efficiently absorbed, whereas the permeability of beta-acids is low. Limiting factors in the absorption of beta-acids could involve P-gp and MRP-2 type efflux transporters and phase II metabolism. PMID:20329731