Edge Of Contacts Research Articles

The Relationship between the Bevel of the Radial Head Epiphysis and the Posterior Synovial Fringe During Rotation of the Elbow: An Ultrasonography Study with Possible Implications Regarding the Pathophysiology of Nursemaid's Elbow.

Nursemaid's elbow is the most common upper extremity injury in children under 5 years of age. However, the exact pathomechanism underlying the nursemaid's elbow remains elusive, and approximate one-third of patients present with a nonclassical history. Using a high-frequency ultrasound probe, we attempted to determine the relationship between the anterior edge of the posterior synovial fringe and the peripheral rim of the radial head epiphysis during rotation. It is possible that the primary reason for the nursemaid's elbow is due to the pronator position. Twenty-one patients had a history of nursemaid's elbow and had a successful reduction before enrollment in this study. A high-frequency linear array 6 to 24 MHz hockey stick transducer was used to detect small morphologic changes in the peripheral rim of the radial head epiphysis and the posterior synovial fringe during rotation of the capitellum-radial joint. In complete pronation, the anterior edge of the posterior synovial fringe contacts the beveled articular surface of the radial head peripheral rim in all 21 patients. In neutral and complete supination, the anterior edge of the posterior synovial fringe contacts the convexly nonarticular surface of the radial head peripheral rim and extends deep into the foveal radius. The posterior synovial fringe and the capsule-aponeurotic membrane were tightened in passive pronation in all 21 cases. The posterior synovial fringe and the capsule-aponeurosis membrane were all loose in the neutral and supination positions. The anterior edge of the posterior synovial fringe touches the beveled peripheral rim of the radial head epiphysis during complete pronation, and the tension of the lateral collateral ligament complex during pronation may further cause unstable conditions of the anterior edge of the posterior synovial fringe. We hypothesized that the beveled peripheral rim of the radial epiphysis and its relationship with the anterior edge of the posterior synovial fringe could be the reason why nursemaid's elbow only occurs while the elbow is in the pronator position.

Enhancing Detectivity of Indium-Oxide-Based Photodetectors via Vertical Nanostructuring Through Glancing Angle Deposition

In2O3 vertical nanostructures (VNS) are fabricated using a glancing angle deposition (GLAD) technique upon an In2O3 thin film (TF) on a n-type silicon (n-Si) substrate. Analysis using high-resolution transmission electron microscopy (HRTEM) and high-resolution x-ray diffraction (HRXRD) revealed that the In2O3 VNS are amorphous in nature. An average ~4.5-fold enhancement in absorption was observed and a microscopic origin was proposed for observed bandgap changes for the n-Si/In2O3 TF/GLAD In2O3 VNS and bare n-Si/In2O3 TF samples in the visible region due to surface-related trap states or oxygen vacancies. The improvement in photodetection was attributed to the presence of a large number of surface-related trap states at the edge of metal contacts. The fabricated VNS detector possesses enhanced photosensitivity (~1.7-fold) due to an efficient photogating effect in the depletion region. A maximum detectivity of ~12.8 × 107 Jones was observed for the n-Si/In2O3 TF/GLAD In2O3 VNS device, which possesses ~15.6-fold enhanced detectivity as compared to the bare n-Si/In2O3 TF device.

Stress intensity factor calibration for short cracks at the edge of semi-infinite contacts

An asymptotic representation of the sub surface stress field allows us to find crack tip stress intensity factors for cracks nucleating from the edge of incomplete contacts. For the asymptotic representation to be valid we require the cracks to be short compared to any other dimension characterising the contact. The general asymptotic formulation allows us to incorporate the results in different contact problems as long as the contact is incomplete. We show that, for the load cases considered, crack closure is not an issue as long as the mode I stress intensity factor is positive.

Arginine Forks Are a Widespread Motif to Recognize Phosphate Backbones and Guanine Nucleobases in the RNA Major Groove.

RNA recognition by proteins is central to biology. Here we demonstrate the existence of a recurrent structural motif, the "arginine fork", that codifies arginine readout of cognate backbone and guanine nucleobase interactions in a variety of protein-RNA complexes derived from viruses, metabolic enzymes, and ribosomes. Nearly 30 years ago, a theoretical arginine fork model was posited to account for the specificity between the HIV-1 Tat protein and TAR RNA. This model predicted that a single arginine should form four complementary contacts with nearby phosphates, yielding a two-pronged backbone readout. Recent high-resolution structures of TAR-protein complexes have unveiled new details, including (i) arginine interactions with the phosphate backbone and the major-groove edge of guanine and (ii) simultaneous cation-π contacts between the guanidinium group and flanking nucleobases. These findings prompted us to search for arginine forks within experimental protein-RNA structures retrieved from the Protein Data Bank. The results revealed four distinct classes of arginine forks that we have defined using a rigorous but flexible nomenclature. Examples are presented in the context of ribosomal and nonribosomal interfaces with analysis of arginine dihedral angles and structural (suite) classification of RNA targets. When arginine fork chemical recognition principles were applied to existing structures with unusual arginine-guanine recognition, we found that the arginine fork geometry was more consistent with the experimental data, suggesting the utility of fork classifications to improve structural models. Software to analyze arginine-RNA interactions has been made available to the community.

Experimental evaluation for internal trapezoidal thread with axial ultrasonic vibration cutting of Ti–6Al–4V

Renewal of the manufacturing process for thread is important in a variety of products and industry applications. Especially for machining the internal trapezoidal thread, the cutting edge is in a semi-closed state, three cutting edges and two cutting tips are in contact with the workpiece, resulting the heat is not easy to spread out. At the same time, the narrow space of the internal thread leads to the poor rigidity of the tool, the instability of the machining state, which seriously affects the surface machining quality of the parts. Here, a new precision processing device of axial ultrasonic-assisted turning (AUAT) is designed, which can achieve the industrial application of machining internal thread parts. The device can work stably at a working frequency of about 28.8 kHz. Secondly, considering that the bottom and flank of the thread need to be machined at the same time, the contact mode of the tool is different between them. The main cutting edge of the tool contacts the workpiece intermittently on the flank tooth, forming the texture surface which is conducive to the transmission of the thread pair. On the bottom teeth, the main cutting edge is always in contact with the workpiece and carries out the axial sawing movement. The high-frequency axial vibration damping effect is obvious, which suppresses the unstable machining state such as chatter and improves the machining surface quality of the bottom teeth. Finally, Ti–6Al–4V trapezoid thread is selected in the verification, in which the separation effect of ultrasonic vibration cutting is verified, the cutting force is tested, and the machined surface topography of the workpiece is analyzed. Experimental results show that the quality of thread was significantly improved in AUAT.

Long distance distortions in the graphene near the edge of planar metal contacts

The properties of the planar junction between graphene layer and thin film metal structures are important for formation of the electronic devices integrating the structures of the two-dimensional materials. However, the properties of the graphene-metal contacts are still weakly controlled in the large area device fabrication. In this report we demonstrated an approach acceptable to characterize the long distance distortion area produced by the metal contact edges in the graphene monolayer. The systematic analysis of the Raman maps of the graphene is performed aiming to describe the changes in the graphene monolayer produced by the technology dependent parameters in the planar structures used for the measurements by the circular transmission line method. It was proved that Au contacts produce the compressive strain in the graphene layer in the distances up to about 2–4 μm from the contact edges. The transition between the n- and p-type of the doping is combined with the compression strain in the long distance graphene distortion area close to the Ni-contact edges. An equivalent electrical circuit is proposed for description of the graphene distortion area near the contact edges.

The Application of Theta Method to Potential Field Gradient Tensor Data for Edge Detection of Complex Geological Structures

Edge detection of magnetized structures is an important application of magnetic filters for geological interpretations. In this way, one can mention methods of the potential field derivatives which are categorized into: methods based on scalar potential field and potential field gradient tensor (PGT) data. Using five independent signal components, methods based on the PGT matrices have higher accuracy than methods based on scalar potential field data. Investigations of various methods of edge detection show that as geologic conditions become more complex, they greatly lose their efficacy and sometimes suffer from distortions. These distortions probably result from the Gibbs phenomenon which occurs in the process of computing the potential field data derivatives. This phenomenon creates false edges and incorrect interpretations of data. The thetaPGT method addresses this phenomenon by combining the PGT matrix and the previously derived theta map method. The maximum value of thetaPGT delineates the horizontal edge of geologic contacts. Achieved results by applying the thetaPGT method on simple and then complex synthetic magnetic models demonstrates higher accuracy of the proposed method in comparison with the analytic signal, theta and horizontal directional theta (HDT) methods. The new method has no sensitivity to depth and strike, and also doesn’t create additional edges. Furthermore, it has lower noise sensitivity and significantly reduces the effect of the Gibbs phenomenon. Finally, applying this method on real magnetic data from the Varzeghan area, northwest Iran, with respect to other methods reveals more details of structures in the area and characterized false faults resulting from the Gibbs phenomenon.

Stability of Schottky and Ohmic Au Nanocatalysts to ZnO Nanowires.

Manufacturable nanodevices must now be the predominant goal of nanotechnological research to ensure the enhanced properties of nanomaterials can be fully exploited and fulfill the promise that fundamental science has exposed. Here, we test the electrical stability of Au nanocatalyst-ZnO nanowire contacts to determine the limits of the electrical transport properties and the metal-semiconductor interfaces. While the transport properties of as-grown Au nanocatalyst contacts to ZnO nanowires have been well-defined, the stability of the interfaces over lengthy time periods and the electrical limits of the ohmic or Schottky function have not been studied. In this work, we use a recently developed iterative analytical process that directly correlates multiprobe transport measurements with subsequent aberration-corrected scanning transmission electron microscopy to study the electrical, structural, and chemical properties when the nanowires are pushed to their electrical limits and show structural changes occur at the metal-nanowire interface or at the nanowire midshaft. The ohmic contacts exhibit enhanced quantum-mechanical edge-tunneling transport behavior because of additional native semiconductor material at the contact edge due to a strong metal-support interaction. The low-resistance nature of the ohmic contacts leads to catastrophic breakdown at the middle of the nanowire span where the maximum heating effect occurs. Schottky-type Au-nanowire contacts are observed when the nanowires are in the as-grown pristine state and display entirely different breakdown characteristics. The higher-resistance rectifying I-V behavior degrades as the current is increased which leads to a permanent weakening of the rectifying effect and atomic-scale structural changes at the edge of the Au interface where the tunneling current is concentrated. Furthermore, to study modified nanowires such as might be used in devices the nanoscale tunneling path at the interface edge of the ohmic nanowire contacts is removed with a simple etch treatment and the nanowires show similar I-V characteristics during breakdown as the Schottky pristine contacts. Breakdown is shown to occur either at the nanowire midshaft or at the Au contact depending on the initial conductivity of the Au contact interface. These results demonstrate the Au-nanowire structures are capable of withstanding long periods of electrical stress and are stable at high current densities ensuring they are ideal components for nanowire-device designs while providing the flexibility of choosing the electrical transport properties which other Au-nanowire systems cannot presently deliver.

CXADR is required for AJ and TJ assembly during porcine blastocyst formation.

Coxsackie virus and adenovirus receptor (CXADR) is a member of the immunoglobulin superfamily as well as a member of the junctional adhesion molecule family of adhesion receptor. In human pre-implantation embryos, CXADR was detected and co-localized with tight junction (TJ) proteins on the membrane of the trophectoderm. However, its physiological roles were not elucidated in terms of blastocyst formation. Here, we reported expression patterns and biological functions of CXADR in porcine pre-implantation embryos. The transcripts of CXADR were detected at all stages of pre-implantation. Particularly, its expression dramatically increased and preferentially localized at the edge of cell-cell contacts, rather than in the nucleus from the eight-cell stage onwards. CXADR expression was knocked down (KD) by microinjecting double-stranded RNA into one-cell parthenotes. The vast majority of CXADR KD embryos failed to develop to the blastocyst stage, and a few developed KD blastocysts did not expand fully. Analysis of adherens junction (AJ)- and TJ-associated genes/proteins using qRT-PCR, immunocytochemistry and assessment of TJ permeability using FITC-dextran uptake assay revealed that the developmental failure and relatively small cavities are attributed to the defects of TJ assembly. In summary, CXADR is necessary for the AJ and TJ assembly/biogenesis during pre-implantation development.

Surface tension regularizes the crack singularity of adhesion.

The elastic and adhesive properties of a solid surface can be quantified by indenting it with a rigid sphere. Indentation tests are classically described by the JKR-law when the solid is very stiff, while recent work highlights the importance of surface tension for exceedingly soft materials. Here we show that surface tension plays a crucial role even in stiff solids: Young's wetting angle emerges as a boundary condition and this regularizes the crack-like singularity at the edge of adhesive contacts. We find that the edge region exhibits a universal, self-similar structure that emerges from the balance of surface tension and elasticity. The similarity theory is solved analytically and provides a complete description of adhesive contacts, by which we reconcile global adhesion laws and local contact mechanics.

An investigation into the reliability and variability of wobble board performance in a healthy population using the SMARTwobble instrumented wobble board

ObjectivesThere is clinical need to provide quantification of wobble board performance. This study aimed to investigate, in a healthy population, wobble board performance, using an instrumented wobble board. DesignExperimental-observational. SettingClinical setting, Bournemouth University. ParticipantsThirty-two healthy volunteers. Main outcome measuresWobble board performance was measured using time spent in tilt angle bandings, on the edge and number of edge contacts. Time was normalised to total time, yielding time as a percentage. ResultsMean (sd) intra-class correlation coefficients (ICC) for percentage-time in each banding was 0.71(0.1); 95% confidence interval (CI) (0.67–0.76) indicating good consistency with repeated performances. Mean (sd) standard error of measurement (SEM) for percentage-time was 4.2% (1.3%); 95% CI (3.6–4.7%) indicating small errors associated with repeated performances. Minimal detectable change was small for percentage-time in tilt bandings (9%) and number of edge contacts (27). One-way ANOVA demonstrated that eyes closed yielded significantly different results to all other conditions. Time in the outer tilt band, on the edge and number of edge contacts may be better at discriminating between tasks in healthy volunteers. ConclusionsThe SMARTwobble board is reliable for measuring balance within a healthy population and provides reference for further clinical studies.

2P1-K03 スナップジョイントを有するパーツの力制御の切り替えに基づく組み立て(動作計画と制御の新展開)

This paper proposes a force controller which assembles parts with snap joints. We use the control basis approach where it is composed of elementary position/force controllers. We first classify the snap joint into three categories. Focusing on the parts having the cantilever type snap joints, we propose the pivot approach where, after the edge of the female part contacts the male part, the female part rotates until all the snap joints contact the male part. The effectiveness of the proposed method is confirmed through experimental results.

Pathoanatomy of Anterior Ankle Impingement in Dancers

Articles from the anatomy, orthopaedic, and radiology literature since 1943 were reviewed, and possible sources of anterior ankle impingement were identified therein. There are both osseous and soft tissue causes of impingement symptoms. Anterior impingement in dancers may be induced by repetitive dorsiflexion during demi-plié, where the anterior edge of the distal tibial articular surface contacts the dorsal neck of the talus. It also can be associated with the sequelae of lateral ankle sprain, including a hypertrophic tissue response, or simply by impingement of anatomically normal ligamentous structures. Dance medicine clinicians should be familiar with the pathoanatomy and etiologies of this clinical entity in order to provide effective care for dancers who suffer from it.

Efficient Charge Extraction out of Nanoscale Schottky Contacts to CdS Nanowires

Charge recombination dynamics in semiconductor nanostructures is of vital importance for photovoltaic or photodetector device applications. We use local photocurrent measurements to explore spatially separated drift- and diffusion-currents close to the edge of gold contacts on top of cadmium sulfide nanowires. By theoretical modeling of the experimental photocurrent profiles, the electron diffusion length and lifetime in the wires are obtained to 0.8 μm and 1 ns, respectively. In contrast to bulk devices, the nanoscale dimensions of the involved Schottky contacts enable a highly efficient charge carrier extraction from below the electrodes. This finding paves the way for designing nanostructured optoelectronic devices of improved performance.

Stable tungsten disilicide contacts for surface and thin film resistivity measurements

High-temperature stable electric contacts of tungsten disilicide (WSi2) on Si(001) are fabricated by a simple two-step process: vacuum deposition of W on the native Si dioxide and subsequent annealing under ultrahigh-vacuum conditions. Silicidation starts at 1000K, as, it is believed to occur, the Si diffuses to the surface through the defects in the oxide. Flash annealing to 1500K removes the oxide, resulting in stable WSi2 contacts on the surface. Contamination due to migrating W is confined to within a micrometer of the edge of the WSi2 contacts. Beyond this micrometer-sized zone, the surface is free of contamination as confirmed by low-energy electron microscopy and high-resolution low-energy electron diffraction. Reproducible resistance curves during annealing and cooling of the Si(001) sample confirm the reliability of the contacts, which can withstand many flash-annealing cycles without degradation.

Crystal Structure of a Major Outer Membrane Protein from Thermus thermophilus HB27

The thermophilic eubacterium Thermus thermophilus belongs to one of the oldest branches of evolution and has a multilayered cell envelope that differs from that of modern Gram-negative bacteria. Its outer membrane contains integral outer membrane proteins (OMPs), of which only a few are characterized. TtoA, a new β-barrel OMP, was identified by searching the genome sequence of strain HB27 for the presence of a C-terminal signature sequence. The structure of TtoA was determined to a resolution of 2.8 Å, representing the first crystal structure of an OMP from a thermophilic bacterium. TtoA consists of an eight-stranded β-barrel with a large extracellular part to which a divalent cation is bound. A five-stranded extracellular β-sheet protrudes out of the membrane-embedded transmembrane barrel and is stabilized by a disulfide bridge. The edge of this β-sheet forms crystal contacts that could mimic interactions with other proteins. In modern Gram-negative bacteria, the C-terminal signature sequence of OMPs is required for binding to an Omp85 family protein as a prerequisite for its assembly. We present hints that a similar assembly pathway exists in T. thermophilus by an in vitro binding assay, where unfolded TtoA binds to the Thermus Omp85 family protein TtOmp85, while a mutant without the signature sequence does not.

Sliding of general frictional complete contacts

The interfacial contact pressure distribution beneath a complete sliding contact between elastically similar components, in the presence of friction, has been studied, with particular reference to contacts whose edge angles are 60°, 90° and 120°. The possible types of behaviour at the edge of contacts, namely power order singularity, power order bounded and square-root bounded, are discussed. The details of the behaviour require a detailed study of a characteristic equation and this shows that the kinds of pressure distribution to be anticipated, which can vary very markedly.

Near-Field Induced FIR Josephson-Detection by c-Axis-Oriented YBa2Cu3O7-δ-Films

A novel approach to intrinsic Josephson-detection of far infrared radiation is reported utilizing near-zone field effects at electric contacts on c-axis oriented YBa2Cu3O7-δ films. While only a bolometric signal was observed focusing the radiation far off the contacts on c-axis normal films, irradiating the edge of contacts yielded an almost wavelength independent fast signal showing the characteristic intensity dependence of Josephson-detection. The signal is attributed to a c-axis parallel component of the electric radiation field being generated in the near-zone field of diffraction at the metallic contact structures.

Design and fabrication of micromirror supported by electroplated nickel posts

A 100 μm × 100 μm aluminium micromirror has been designed and fabricated using a thick photoresist as a sacrificial layer and as a mould for nickel electroplating. The micromirror is composed of an aluminium mirror plate, two nickel support posts, two aluminium hinges, two address electrodes and two landing electrodes. The aluminium mirror plate, which is supported by the two nickel support posts, is overhung about 10 μm from the silicon substrate. We use thick photoresist to obtain a 10 μm thick sacrificial layer and electroplate nickel to obtain a support post 10 μm high. The aluminium mirror plate is actuated like a seesaw by electrostatic force generated by an electrostatic potential difference applied between the mirror plate and the address electrode. We use RIE (reactive ion etching) in a final step to release the micromirror plate from the silicon substrate. The edge of the mirror plate contacts the substrate (maximum deflection) when the potential difference between the mirror plate and the address electrode is 35 V, and the mirror is released from the substrate when the potential difference reduces to 22 V.

Growth kinetics of Si hemispherical grains on clean amorphous-Si surfaces

In solid-phase growth on SiO2 layers of amorphous-Si (a-Si) having clean, native oxide-free surfaces under ultrahigh vacuum conditions, a novel mode of crystallization can be observed: upward growth of Si grains resulting in the formation of nearly hemispherical-shaped grains protruding from the flat surface. Kinetics of the grain growth has been studied by measuring the annealing time and temperature dependence of the hemispherical grain size. The growth behavior is well explained by a model based on the crystallization of surface diffusive atoms supplied only from where the edge of the hemispherical grain contacts the a-Si surface. The activation energy for hemispherical grain growth was found to be 2.3±0.1 eV from the temperature dependence of the flux density, defined as the number of atoms crystallized per unit time per unit surface area enclosed by the edge. The atomistic mechanism for the hemispherical shape formation and the origin of the activation energy are also discussed.