Rapid [Gamma]-amino acid synthesis and the inhibition of the growth and development of oblique banded leaf-roller larvae

The hypothesis that rapid y-aminobutyric acid (GABA) accumulation is a plant defense against phytophagous insects was investigated. Simulation of mechanical damage resulting from phytophagous insect activity increased soybean (Glycine max L.) leaf GABA 10- to 25-fold within 1 to 4 min. Pulverizing leaf tissue resulted in a value of 2. 15 (±O. 11 SE) ~mol GABA per gram fresh weight. Increasing the GABA levels in a synthetic diet from 1.6 to 2.6 Jlffiol GABA per gram fresh weight reduced the growth rates, developmental rates, total biomass (50% reduction), and survival rates (30% reduction) of cultured Oblique banded leaf-roller (OBLR) (Choristonellra rosacealla Harris) larvae. In field experiments OBLR larvae were found predominantly on young terminal leaves which have a reduced capacity to produce GABA in response to mechanical damage. Glutamate decarboxylase (GAD) is a cytosolic enzyme which catalyses the decarboxylation of L-Glu to GABA. GAD is a calmodulin binding enzyme whose activity is stimulated dramatically by increased cytosolic H+ or Ca2 + ion concentrations. Phytophagous insect activity will disrupt the cellular compartmentation of H+ and Ca2 +, activate GAD and subsequent GABA accumulation. In animals GABA is a major inhibitory neurotransmitter. The possible mechanisms resulting in GABA inhibited growth and development of insects are discussed.

Graphics for engineers, architects, and builders : a manual for designers, an a text - book for scientific schools. Trusses and arches analyzed and discussed by graphical methods

UANL

Graphics for engineers, architects, and builders : a manual for designers, and a text-book for technical school, trussesand arches analyzed and descussed by graphical methods

UANL

Phylogénomique des Archées

Les transferts horizontaux de gènes (THG) ont été démontrés pour jouer un rôle important dans l'évolution des procaryotes. Leur impact a été le sujet de débats intenses, ceux-ci allant même jusqu'à l'abandon de l'arbre des espèces. Selon certaines études, un signal historique dominant est présent chez les procaryotes, puisque les transmissions horizontales stables et fonctionnelles semblent beaucoup plus rares que les transmissions verticales (des dizaines contre des milliards). Cependant, l'effet cumulatif des THG est non-négligeable et peut potentiellement affecter l'inférence phylogénétique. Conséquemment, la plupart des chercheurs basent leurs inférences phylogénétiques sur un faible nombre de gènes rarement transférés, comme les protéines ribosomales. Ceux-ci n'accordent cependant pas autant d'importance au modèle d'évolution utilisé, même s'il a été démontré que celui-ci est important lorsqu'il est question de résoudre certaines divergences entre ancêtres d'espèces, comme pour les animaux par exemple. Dans ce mémoire, nous avons utilisé des simulations et analyser des jeux de données d'Archées afin d'étudier l'impact relatif des THG ainsi que l'impact des modèles d'évolution sur la précision phylogénétique. Nos simulations prouvent que (1) les THG ont un impact limité sur les phylogénies, considérant un taux de transferts réaliste et que (2) l'approche super-matrice est plus précise que l'approche super-arbre. Nous avons également observé que les modèles complexes expliquent non seulement mieux les données que les modèles standards, mais peuvent avoir un impact direct sur différents groupes phylogénétiques et sur la robustesse de l'arbre obtenu. Nos résultats contredisent une publication récente proposant que les Thaumarchaeota apparaissent à la base de l'arbre des Archées.

Surface evolution of amorphous nanocolumns of Fe–Ni grown by oblique angle deposition

The growth of Fe–Ni based amorphous nanocolumns has been studied using atomic force microscopy. The root mean square roughness of the film surface increased with the deposition time but showed a little change at higher deposition time. It was found that the separation between the nanostructures increased sharply during the initial stages of growth and the change was less pronounced at higher deposition time. During the initial stages of the column growth, a roughening process due to self shadowing is dominant and, as the deposition time increases, a smoothening mechanism takes place due to the surface diffusion of adatoms

Oblique Angle Deposition of Germanium Film on Silicon Substrate

The effect of flux angle, substrate temperature and deposition rate on obliquely deposited germanium (Ge) films has been investigated. By carrying out deposition with the vapor flux inclined at 87° to the substrate normal at substrate temperatures of 250°C or 300°C, it may be possible to obtain isolated Ge nanowires. The Ge nanowires are crystalline as shown by Raman Spectroscopy.

Toughness & oblique metalcutting

The implications of whether new surfaces in cutting are formed just by plastic flow past the tool or by some fracturelike separation process involving significant surface work, are discussed. Oblique metalcutting is investigated using the ideas contained in a new algebraic model for the orthogonal machining of metals (Atkins, A. G., 2003, "Modeling Metalcutting Using Modern Ductile Fracture Mechanics: Quantitative Explanations for Some Longstanding Problems," Int. J. Mech. Sci., 45, pp. 373–396) in which significant surface work (ductile fracture toughnesses) is incorporated. The model is able to predict explicit material-dependent primary shear plane angles and provides explanations for a variety of well-known effects in cutting, such as the reduction of at small uncut chip thicknesses; the quasilinear plots of cutting force versus depth of cut; the existence of a positive force intercept in such plots; why, in the size-effect regime of machining, anomalously high values of yield stress are determined; and why finite element method simulations of cutting have to employ a "separation criterion" at the tool tip. Predictions from the new analysis for oblique cutting (including an investigation of Stabler's rule for the relation between the chip flow velocity angle C and the angle of blade inclination i) compare consistently and favorably with experimental results.

Oblique h.f. radiowave propagation in the main trough region of the ionosphere

The propagation of 7.335 MHz, c.w. signals over a 5212 km sub-auroral, west-east path is studied. Measurements and semi-empirical predictions are made of the amplitude distributions and Doppler shifts of the received signals. The observed amplitude distribution is fitted with one produced by a numerical fading model, yielding the power losses suffered by the signals during propagation via the predominating modes. The signals are found to suffer exceptionally low losses at certain local times under geomagnetically quiet conditions. The mid-latitude trough in the F2 peak ionization density is predicted by a statistical model to be at the latitudes of this path at these times and at low Kp values. A sharp cut-off in low-power losses at a mean Kp of 2.75 strongly implicates the trough in the propagation of these signals. The Doppler shifts observed at these times cannot be explained by a simple ray-tracing model. It is shown however, that a simple extension of this model to allow for the trough can reproduce the form of the observed diurnal variation.

Fracture Resistance of the Implant-Abutment Connection in Implants with Internal Hex and Internal Conical Connections Under Oblique Compressive Loading: An In Vitro Study

The objective of this study was to verify if differences in the design of internal hex (IH) and internal conical (IC) connection implant systems influence fracture resistance under oblique compressive forces. Twenty implant-abutment assemblies were utilized: 10 with IH connections and 10 with IC connections. Maximum deformation force for IC implants (90.58 +/- 6.72 kgf) was statistically higher than that for IH implants (83.73 +/- 4.94 kgf) (P = .0182). Fracture force for the IH implants was 79.86 +/- 4.77 kgf. None of the IC implants fractured. The friction-locking mechanics and the solid design of the IC abutments provided greater resistance to deformation and fracture under oblique compressive loading when compared to the IH abutments. Int J Prosthodont 2009;22:283-286.

Optimization in multi-implant placement for immediate loading in edentulous arches using a modified surgical template and prototyping: A case report

Immediate loading of dental implants shortens the treatment time and makes it possible to give the patient an esthetic appearance throughout the treatment period. Placement of dental implants requires precise planning that accounts for anatomic limitations and restorative goals. Diagnosis can be made with the assistance of computerized tomographic scanning, but transfer of planning to the surgical field is limited. Recently, novel CAD/CAM techniques such as stereolithographic rapid prototyping have been developed to build surgical guides in an attempt to improve precision of implant placement. The aim of this case report was to show a modified surgical template used throughout implant placement as an alternative to a conventional surgical guide.

Deficiency of the Cytoskeletal Protein SPECC1L Leads to Oblique Facial Clefting

Genetic mutations responsible for oblique facial clefts (ObFC), a unique class of facial malformations, are largely unknown. We show that loss-of-function mutations in SPECC1L. are pathogenic for this human developmental disorder and that SPECC1L is a critical organizer of vertebrate facial morphogenesis. During murine embryogenesis, Speed 1 1 is expressed in cell populations of the developing facial primordial, which proliferate and fuse to form the face. In zebrafish, knockdown of a SPECC1L homolog produces a faceless phenotype with loss of jaw and facial structures, and knockdown in Drosophila phenocopies mutants in the integrin signaling pathway that exhibit cell-migration and -adhesion defects. Furthermore, in mammalian cells, SPECC1L colocalizes with both tubulin and actin, and its deficiency results in defective actin-cytoskeleton reorganization, as well as abnormal cell adhesion and migration. Collectively, these data demonstrate that SPECC1L functions in actin-cytoskeleton reorganization and is required for proper facial morphogenesis.

CAE crash analysis of structures in oblique loading

This work focussed on how tubular steel structures similar to that in frontal car frames deform under crash conditions. The novelty comes from finding three crash modes: axial crush, transitional and global bending. Each mode was categorised by reaction force and energy absorption, this allowing for better structural design practices.