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Orientation Changes (orientation + change)
Selected AbstractsAssessing suturing techniques using a virtual reality surgical simulatorMICROSURGERY, Issue 6 2010Hamed Kazemi M.Eng. Advantages of virtual-reality simulators surgical skill assessment and training include more training time, no risk to patient, repeatable difficulty level, reliable feedback, without the resource demands, and ethical issues of animal-based training. We tested this for a key subtask and showed a strong link between skill in the simulator and in reality. Suturing performance was assessed for four groups of participants, including experienced surgeons and naive subjects, on a custom-made virtual-reality simulator. Each subject tried the experiment 30 times using five different types of needles to perform a standardized suture placement task. Traditional metrics of performance as well as new metrics enabled by our system were proposed, and the data indicate difference between trained and untrained performance. In all traditional parameters such as time, number of attempts, and motion quantity, the medical surgeons outperformed the other three groups, though differences were not significant. However, motion smoothness, penetration and exit angles, tear size areas, and orientation change were statistically significant in the trained group when compared with untrained group. This suggests that these parameters can be used in virtual microsurgery training. © 2010 Wiley-Liss, Inc. Microsurgery 30:479,486, 2010. [source] A New Molecular Switch Based on Helical BiladienoneADVANCED MATERIALS, Issue 19 2006E. Matsui A molecular field-effect switch (FES) employing zinc biladienone as the active element is reported (see figure). The switching mechanism is investigated and a new FES switching mechanism is proposed in which the molecules separate from the electrodes and their molecular orientation changes when a gate voltage is applied. [source] Synchrotron texture analysis with area detectorsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2003H.-R. Wenk The wide availability of X-ray area detectors provides an opportunity for using synchrotron radiation based X-ray diffraction for the determination of preferred crystallite orientation in polycrystalline materials. These measurements are very fast compared to other techniques. Texture is immediately recognized as intensity variations along Debye rings in diffraction images, yet in many cases this information is not used because the quantitative treatment of texture information has not yet been developed into a standard technique. In special cases it is possible to interpret the texture information contained in these intensity variations intuitively. However, diffraction studies focused on the effects of texture on materials properties often require the full orientation distribution function (ODF) which can be obtained from spherical tomography analysis. In cases of high crystal symmetry (cubic and hexagonal) an approximation to the full ODF can be reconstructed from single diffraction images, as is demonstrated for textures in rolled copper and titanium sheets. Combined with area detectors, the reconstruction methods make the measurements fast enough to study orientation changes during phase transformations, recrystallization and deformation in situ, and even in real time, at a wide range of temperature and pressure conditions. The present work focuses on practical aspects of texture measurement and data processing procedures to make the latter available for the growing community of synchrotron users. It reviews previous applications and highlights some opportunities for synchrotron texture analysis based on case studies on different materials. [source] Characterization of site I of human serum albumin using spectroscopic analyses: Locational relations between regions Ib and Ic of site IJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2004Keishi Yamasaki Abstract Site I of human serum albumin is an important and complex region for high-affinity binding of drugs. Equilibrium dialysis showed independent binding of dansyl- L -asparagine (DNSA) and n -alkyl p -aminobenzoates (p -ABEs) to regions Ib and Ic, respectively, in the pH range 6.0,9.0. However, individual binding of DNSA increased with pH in the same range. Binding of the four n -alkyl p -ABEs strongly perturbed the circular dichroism spectrum of bound DNSA, and the effect increased with concentration and the number of carbon atoms in the alkyl moiety. A similar effect was observed by increasing pH from 6.0 to 9.0, a pH range in which human serum albumin is known to undergo the neutral-to-base transition. The spectral changes propose spatial orientation changes of DNSA at region Ib. This proposal was supported by increased fluorescence anisotropy values: n -alkyl p -ABEs binding and the pH-dependent conformational change each restricted the mobility of the naphthalene ring of bound DNSA. Despite the similar effects on the spatial orientation of DNSA, clear differences were observed between the effects of n -alkyl p -ABEs and neutral-to-base transition. The former hardly changed the affinity and maximum fluorescence emission wavelength of bound DNSA; in contrast, the latter significantly affected them. The results give new information about site I and, according to our knowledge, represent a new type of ligand interaction, because the binding site of DNSA could be changed by simultaneous binding of the n -alkyl p -ABEs without affecting the binding constant. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:3004,3012, 2004 [source] Flower orientation on slopes in the myco-heterotrophic species Monotropastrum globosumPLANT SPECIES BIOLOGY, Issue 3 2007AKIO IMAMURA Abstract We investigated the factors that determine the flower orientation of Monotropastrum globosum on a slope, and their effects on reproductive success. A previous study revealed that flowers on a slope faced the open space, which was presumed to increase pollinator attraction, and that orientation affected the reproductive success of individual flowers. When a plant has many inflorescences, interference among flowers may occur. We conducted a shading experiment to examine whether flower orientation changes in response to light conditions based on the angular distance between the slope and the flower direction (ADSF), and we analyzed the correlations between the position of individual flowers within plants, flower angle and ADSF, and the relationships between pollination and fruiting success and flower orientation. The shading experiment revealed that the flower orientation of M. globosum was affected by light, slope angle and flower position within a plant. The ADSF of the front flowers was smaller than that of the back flowers. However, flower orientation did not significantly affect either pollination or fruiting success, although the petal size of each flower did affect reproductive success. In M. globosum with multi-inflorescences, individual flowers may face the open space to reduce interference among flowers within an individual. [source] Intracortical modulation of cortical-bulbar responses for the masseter muscleTHE JOURNAL OF PHYSIOLOGY, Issue 14 2008Enzo Ortu Short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) were evaluated in the masseter muscles of 12 subjects and the cortical silent period (SP) in nine subjects. Motor evoked potentials (MEPs) were recorded from contralateral (cMM) and ipsilateral (iMM) masseters, activated at 10% of maximal voluntary contraction (MVC). Interstimulus intervals (ISIs) were 2 and 3 ms for SICI, 10 and 15 ms for ICF. TMS of the left masseteric cortex induced MEPs that were larger in the cMM than the iMM; stimulation of right masseteric cortex produced a similar asymmetry in response amplitude. SICI was only observed using a CS intensity of 70% AMT and was equal in both cMM and iMM. SICI was stronger at higher TS intensities, was abolished by muscle activation greater than 10% MVC, and was unaffected by coil orientation changes. Control experiments confirmed that SICI was not contaminated by any inhibitory peripheral reflexes. However, ICF could not be obtained because it was masked by bilateral reflex depression of masseter EMG caused by auditory input from the coil discharge. The SP was bilateral and symmetric; its duration ranged from 35 to 70 ms depending on TS intensity and coil orientation. We conclude that SICI is present in the cortical representation of masseter muscles. The similarity of SICI in cMM and iMM suggests either that a single pool of inhibitory interneurons controls ipsi- and contralateral corticotrigeminal projections or that inhibition is directed to bilaterally projecting corticotrigeminal fibres. Finally, the corticotrigeminal projection seems to be weakly influenced by inhibitory interneurons mediating the cortical SP. [source] | |||||||||||||