Description of Hoplolaimus bachlongviensis sp. n. (Nematoda : Hoplolaimidae) from banana soil in Vietnam

Background The genus Hoplolaimus Daday, 1905 belongs to the subfamily Hoplolaimine Filipiev, 1934 of family Hoplolaimidae Filipiev, 1934 (Krall 1990). Daday established this genus on a single female of H. tylenchiformis recovered from a mud hole on Banco Island, Paraguay in 1905 (Sher 1963, Krall 1990). Hoplolaimus species are distributed worldwide and cause damage on numerous agricultural crops (Luc et al. 1990Robbins et al. 1998). In 1992, Handoo and Golden reviewed 29 valid species of genus Hoplolaimus Dayday, 1905 (Handoo and Golden 1992). Siddiqi (2000) recognised three subgenera in Hoplolaimus: Hoplolaimus (Hoplolaimus) with ten species, is characterized by lateral field distinct, with four incisures, excretory pore behind hemizonid; Hoplolaimus (Basirolaimus) with 18 species, is characterized by lateral field with one to three incisures, obliterated, excretory pore anterior to hemizonid, dorsal oesophageal gland quadrinucleate; and Hoplolaimus (Ethiolaimus) with four species is characterized by lateral field with one to three incisures, obliterated; excretory pore anterior to hemizonid, dorsal oesophageal gland uninucleate (Siddiqi 2000). Since then, Hoplolaimus puriensis Ali, Shaheen & Pervez, 2009 has been described (Ali et al. 2009). Up to now, there have been two species of genus Hoplolaimus reported in Vietnam, viz H. seinhorsti and H. chambus (Nguyen and Nguyen 2000). New information Hoplolaimus bachlongviensis sp. n. was isolated from banana soil in Bach Long Vi Island, Vietnam. The female of this species is described and illustrated below. Some diagnostic characters of this species include body slightly curved ventrally, offset lip region exhibiting three to four annules, lateral field reduced, pharyngeal glands with six nuclei, excretory pore anterior to hemizonid, epiptygma absent, intestine not overlapping rectum and male was not found

Edges and linearization: A reply

This is my reply to the commentaries on Trinh (2009). I thank the commentators – Enoch Aboh, Josef Bayer, Nigel Duffield, Roland Hinterhölzl, Anders Holmberg, Shinichiro Ishihara and Gereon Müller – for their helpful critiques, which point out several shortcomings of the target paper, opened up areas where new predictions can be made and raised questions to be investigated in future research. It is unfortunate that these critiques and this reply did not appear in the same volume. The first section of the reply will hence be a brief summary of my proposal. The theory will be presented in a slightly different way, more transparent than the original formulation but equivalent with it in content. It is my hope that the reformulation will address some of the questions raised in the commentaries. Other issues are discussed in the sections that follo

NASA Propulsion Sub-System Concept Studies and Risk Reduction Activities for Resource Prospector Lander

NASA's exploration roadmap is focused on developing technologies and performing precursor missions to advance the state of the art for eventual human missions to Mars. One of the key components of this roadmap is various robotic missions to Near-Earth Objects, the Moon, and Mars to fill in some of the strategic knowledge gaps. The Resource Prospector (RP) project is one of these robotic precursor activities in the roadmap. RP is a multi-center and multi-institution project to investigate the polar regions of the Moon in search of volatiles. The mission is rated Class D and is approximately 10 days, assuming a five day direct Earth to Moon transfer. Because of the mission cost constraint, a trade study of the propulsion concepts was conducted with a focus on available low-cost hardware for reducing cost in development, while technical risk, system mass, and technology advancement requirements were also taken into consideration. The propulsion system for the lander is composed of a braking stage providing a high thrust to match the lander's velocity with the lunar surface and a lander stage performing the final lunar descent. For the braking stage, liquid oxygen (LOX) and liquid methane (LCH4) propulsion systems, derived from the Morpheus experimental lander, and storable bi-propellant systems, including the 4th stage Peacekeeper (PK) propulsion components and Space Shuttle orbital maneuvering engine (OME), and a solid motor were considered for the study. For the lander stage, the trade study included miniaturized Divert Attitude Control System (DACS) thrusters (Missile Defense Agency (MDA) heritage), their enhanced thruster versions, ISE-100 and ISE-5, and commercial-off-the-shelf (COTS) hardware. The lowest cost configuration of using the solid motor and the PK components while meeting the requirements was selected. The reference concept of the lander is shown in Figure 1. In the current reference configuration, the solid stage is the primary provider of delta-V. It will generate 15,000-lbf of thrust with a single burn of ~ 80's seconds. The lander stage is a bi-propellant, pressure-regulated, pulsing liquid propulsion system to perform all other functions

Prediction of engine performance and wall erosion due to film cooling for the 'fast track' ablative thrust chamber

Efforts have been made at the Propulsion Laboratory (MSFC) to design and develop new liquid rocket engines for small-class launch vehicles. Emphasis of the efforts is to reduce the engine development time with the use of conventional designs while meeting engine reliability criteria. Consequently, the engine cost should be reduced. A demonstrative ablative thrust chamber, called 'fast-track', has been built. To support the design of the 'fast-track' thrust chamber, predictions of the wall temperature and ablation erosion rate of the 'fast-track' thrust chamber have been performed using the computational fluid dynamics program REFLEQS (Reactive Flow Equation Solver). The analysis is intended to assess the amount of fuel to be used for film cooling so that the erosion rate of the chamber ablation does not exceed its allowable limit. In addition, the thrust chamber performance loss due to an increase of the film cooling is examined

Characterization of New RSV-F-Mutants Using BAC Technology Reflecting Their Impact on Viral Growth and Palivizumab Susceptibility

Respiratory syncytial virus (RSV) is one of the most serious pathogens causing severe lower respiratory infections in young children, in the elderly and immunocompromised patients. Globally, there were as many as 118 200 deaths of children under 5 years caused by RSV in 2015. Despite clear clinical needs, treatment approaches for severe RSV-infection remain unsatisfactory. Palivizumab is a monoclonal antibody that targets the fusion F protein on the RSV envelope and is prophylactically administered to high-risk children to prevent a severe RSV infection. Several palivizumab resistance-associated mutations in the RSV-F protein were identified and characterized. Marker transfer analysis is a method that allows a reliable characterization of newly detected mutations with unknown phenotype, and for RSV it is just available to a limited extent. This work engaged itself with the establishment of maker transfer analysis for RSV and standardization of in vitro assays characterizing identified mutations in the RSV-F gene with respect to their influence on viral replication and palivizumab susceptibility. Via “en passant” mutagenesis, mutations were respectively introduced into the bacterial artificial chromosome (BAC) pSynkRSV-l19F (BEI Resources Nr-36460). Generation of recombinant RSV-F-Mutants was successful and stable within this system. Growth of recombinant virus and palivizumab susceptibility were then examined in vitro. In this work, nine single mutations were characterized: C21G, Q34R, R49K, T100S, A103P, K272E, N276S, A518V, C550Y, whereby K272E and N276S are known mutations. Furthermore, the following combinations of mutations C21G/R49K, Q34R/C550Y and T100S/A518V were characterized. Recombinant RS viruses do not differ from wildtype virus in their growth kinetics. Concerning palivizumab susceptibility, it can be confirmed that mutation K272E confers to the virus a stable resistance to palivizumab. Mutations R49K and A103P resulted in 2-fold higher IC50 values compared to the parental strain. RSV variants with mutation Q34R or C550Y were similarly susceptible to palivizumab as the parental strain. Remarkably, mutant that contained both mutations Q34R and C550Y showed significant higher IC50 value compared to the reference strain. This might point out that accumulation of trivial mutations might impact the viral phenotype and thus mutations should be characterized in the context of the whole genetic background. In addition, a new thickening agent, colloidal microcrystalline cellulose was tested for replacement of methylcellulose in the overlay medium used in plaque reduction neutralization assay (PRNA). A concentration of 1.5% colloidal microcrystalline cellulose was shown to be sufficient for the use in PRNA

Self-Adjusting Liquid Injectors for Combustors

A class of self-adjusting injectors for spraying liquid oxidizers and/or fuels into combustion chambers has been proposed. The proposed injectors were originally intended for use in rocket-engine combustion chambers, but could also be used to improve control over flows of liquid propellants in other combustion chambers. The basic idea of the proposed injectors is to use simple mechanisms, inside the injectors themselves, to adjust inlet areas so as to keep injection pressure drops at or near optimum values through out wide throttling ranges. These mechanisms would be actuated by the very pressure drops that they are intended to regulate

Status of Liquid Oxygen/Liquid Methane Injector Study for a Mars Ascent Engine

Preliminary mission studies for human exploration of Mars have been performed at Marshall Space Flight Center (MSFC). These studies indicate that for non-toxic chemical rockets only a cryogenic propulsion system would provide high enough performance to be considered for a Mars ascent vehicle. Although the mission is possible with Earth-supplied propellants for this vehicle, utilization of in-situ propellants is highly attractive. This option would significantly reduce the overall mass of the return vehicle. Consequently, the cost of the mission would be greatly reduced because the number and size of the Earth launch vehicle(s) needed for the mission decrease. NASA/Johnson Space Center has initiated several concept studies (2) of in-situ propellant production plants. Liquid oxygen (LOX) is the primary candidate for an in-situ oxidizer. In-situ fuel candidates include methane (CH4), ethylene (C2H4), and methanol (CH3OH). MSFC initiated a technology development program for a cryogenic propulsion system for the Mars human exploration mission in 1998. One part of this technology program is the effort described here: an evaluation of propellant injection concepts for a LOX/liquid methane Mars Ascent Engine (MAE) with an emphasis on light-weight, high efficiency, reliability, and thermal compatibility. In addition to the main objective, hot-fire tests of the subject injectors will be used to test other key technologies including light-weight combustion chamber materials and advanced ignition concepts. This state-of-the-art technology will then be applied to the development of a cryogenic propulsion system that will meet the requirements of the planned Mars sample return (MSR) mission. The current baseline propulsion system for the MSR mission uses a storable propellant combination [monomethyl hydrazine/mixed oxides of nitrogen-25(MMH/MON-25)]. However, a mission option that incorporates in-situ propellant production and utilization for the ascent stage is being carefully considered as a subscale precursor to a future human mission to Mars

Method for Determining Optimum Injector Inlet Geometry

A method for determining the optimum inlet geometry of a liquid rocket engine swirl injector includes obtaining a throttleable level phase value, volume flow rate, chamber pressure, liquid propellant density, inlet injector pressure, desired target spray angle and desired target optimum delta pressure value between an inlet and a chamber for a plurality of engine stages. The method calculates the tangential inlet area for each throttleable stage. The method also uses correlation between the tangential inlet areas and delta pressure values to calculate the spring displacement and variable inlet geometry of a liquid rocket engine swirl injector

Injector Element which Maintains a Constant Mean Spray Angle and Optimum Pressure Drop During Throttling by Varying the Geometry of Tangential Inlets

A method for determining the optimum inlet geometry of a liquid rocket engine swirl injector includes obtaining a throttleable level phase value, volume flow rate, chamber pressure, liquid propellant density, inlet injector pressure, desired target spray angle and desired target optimum delta pressure value between an inlet and a chamber for a plurality of engine stages. The tangential inlet area for each throttleable stage is calculated. The correlation between the tangential inlet areas and delta pressure values is used to calculate the spring displacement and variable inlet geometry. An injector designed using the method includes a plurality of geometrically calculated tangential inlets in an injection tube; an injection tube cap with a plurality of inlet slots slidably engages the injection tube. A pressure differential across the injector element causes the cap to slide along the injection tube and variably align the inlet slots with the tangential inlets

Extension de la réaction de Julia-Kocienski intramoléculaire sur les imides et Application vers la synthèse totale d’un analogue oxo du FR901483

“-Izidines” units are often found as structural subunits of many alkaloids. One of the powerful methods to access this structure is the formation of the C=C bond exendo. The application of the intramolecular Julia-Kocienski reaction on imides should allow this formation.Our group has a long-standing interest in the application of the Julia-Kocienski reaction on lactones. In line with previous efforts, the herein presented work details the syntheses of enamides via application of the intramolecular Julia-Kocienski reaction on imides. This new method enables us to obtain different “-Izidine” units such as pyrrolizidine, indolizidine, and quinolizidine. Depending on the reaction conditions, it is possible to obtain the enamide or vinylsulfones. In both reactions, the present moiety on imides can affect the outcome.Computational mechanistic study, by collaboration with Dr. Lionel Perrin, shows the steric or electronic effect of the present functional groups on imides influence the results of the formation of the enamides or vinylsulfones.Having a goal of applying this new methodology towards total synthesis of natural products, we started the synthesis of oxo-analog of FR901483. During our synthesis, a number of uncommon reactivities of the presented functional groups were observed. This phenomenon led us to applying different methods than those of the literatureLes « -Izidines » sont des motifs présents dans de nombreuses alcaloïdes. Pour accéder à ces structures, la formation de la liaison C=C exendo est une méthode de choix. L’application de la réaction de Julia-Kocienski intramoléculaire sur des imides permettrait d’obtenir des enamides portant la liaison C=C exendo. Notre équipe s’est intéressée depuis 2005 à l’application de la réaction de Julia-Kocienski les lactones. Dans la continuité de travaux précédents, cette thèse décrit l’application de la réaction de Julia-Kocienski intramoléculaire pour former des enamides. Cette réaction permet d’obtenir tous les motifs « -Izidine » tels que le pyrrolidizine, l’indolizidine ou le quinolizidine. Selon les conditions réactionnelles, il est possible d’obtenir les enamides ou les vinylsulfones. Pour ces deux types de réactions, les résultats obtenus peuvent être classés en fonction des groupements présents sur les imidesL’étude mécanistique par les calculs de DFT, en collaboration avec Dr. Lionel Perrin, montre que l’effet stérique ou électronique des groupements sur les imides peut influencer les résultats de la formation des enamides ou des vinylsulfones. Afin d’illustrer la méthodologie de la réaction de Julia-Kocienski intramoléculaire sur les imides, un analogue oxo du FR901483 a été choisi comme une cible de la synthèse totale. Les réactivités différentes de celles observées dans la littérature des groupements présents sur les intermédiaires nous avons conduits à appliquer d’autres alternatives à littérature. Ce phénomène pourrait bien être lié à l’interaction entre les groupements sur une espace atomique restrein