Internal Wire Research Articles

The ciliary smooth muscle electrotransfer: basic principles and potential for sustained intraocular production of therapeutic proteins

We have developed a nonviral gene therapy method based on the electrotransfer of plasmid in the ciliary muscle. These easily accessible smooth muscle cells could be turned into a biofactory for any therapeutic proteins to be secreted in a sustained manner in the ocular media. Electrical conditions, design of electrodes, plasmid formulation, method and number of injections were optimized in vivo in the rat by localizing β-galactosidase expression and quantifying reporter (luciferase) and therapeutic (anti-tumor necrosis factor) proteins secretion in the ocular media. Anatomical measurements were performed via human magnetic resonance imaging to design a human eye-sized prototype that was tested in the rabbit. In the rat, transscleral injection of 30 µg of plasmid diluted in half saline (77 mM NaCl) followed by application of eight square-wave electrical pulses (15 V, 10 ms, 5.3 Hz) using two platinum/iridium electrodes, an internal wire and an external sheet, delivered plasmid efficiently to the ciliary muscle fibers. Gene transfer resulted in a long-lasting (at least 5 months) and plasmid dose-/injection number- dependent secretion of different molecular weight proteins mainly in the vitreous, without any systemic exposure. Because ciliary muscle anatomical measurements remained constant among ages in adult humans, an integrated device comprising needle-electrodes was designed and manufactured. Its usefulness was validated in the rabbit. Plasmid electrotransfer to the ciliary muscle with a suitable medical device represents a promising local and sustained protein delivery system for treating posterior segment diseases, avoiding repeated intraocular injections.

Improvement of electromechanical properties of an ITER internal tin Nb3Sn wire

The critical current of an internal tin Nb3Sn wire developed by Oxford Instruments, Superconducting Technology for International Thermonuclear Experimental Reactor (ITER) (OST type-I, billet No. 7567) has been studied under axial strain at fields between 12 and 19 T at 4.2 K. Simulating the situation in a cable in conduit, where thermally induced compressive strain is important, a single wire (strand) was jacketed with AISI 316L stainless steel. The reinforced wire shows an important increase in εm, the applied strain where Ic reaches its maximum, from 0.25% to 0.57%. In addition the irreversibility limit, εirr, is improved from 0.50% applied strain to >1.10%. It could also be shown that the Ic at zero intrinsic strain is almost identical. This demonstrates that jacketing does not influence the physical parameters of the original wire. Experimental data of the bare wire has been well fitted by different strain functions. However, it was not possible to model the data of the jacketed wire. There are indications that only models which take into account the multidimensional character of strain are able to describe the behavior but further development is required.

Rotating Heat Pipe Performance with Internal Wire Mesh Screens

The performance of a rotating heat pipe was optimized in terms of the fluid charge ratio, speed of rotation, tapering angle together with relative positions, and the packing ratio of porous filling screens. The favourable effect of porous layers was testified by employing an inner liner along the whole tube interior surface to enhance both evaporation and condensation. The porosity effect was extended to include the whole pipe cross-section such that different configurations of screen layers packed together to form a turbulent extended heat transfer corrugated surface were investigated. It was found that the longitudinal temperature distribution along the heat pipe became more uniform as both the speed of rotation and the tapering angle increased, thus indicating a decrease in the heat pipe thermal resistance. Owing to the fact that enhanced evaporation and condensation take place, the overall heat transfer coefficient increased and the thermal capacity operational limits were extended by increasing the centrifugal acceleration within the stratified flow regime across the speed range of 0—700 r/min. The insertion of porous screens increased the rates of turbulent heat and mass transfer as well as the optimum charge ratio. By optimizing the porous configuration in terms of number of layers and bore size, the decrease in longitudinal temperature difference due to enhanced convection over-rode the increase in saturation temperature difference due to pressure drop. The increased fluid temperature uniformity in the core region, accompanied by severe radial temperature gradients close to the wall, thus revealed increased rates of convective heat transport.

Soft Tissue Profile Changes After Bilateral Sagittal Split Osteotomy for Mandibular Setback: A Systematic Review

To evaluate the ratio of soft tissue to hard tissue in bilateral sagittal split setback osteotomy with rigid internal fixation or wire fixation. A literature search was performed using PubMed, Medline, CINAHL, Web of Science, the Cochrane Library, and Google Scholar Beta. From the original 766 articles identified, 8 articles were included. Two articles were prospective and 6 retrospective. The follow-up period ranged from 1 year to 12.7 years for rigid internal fixation. Two articles on wire fixation were found to be appropriate for inclusion. The differences between short- and long-term ratios of the lower lip to lower incisors for bilateral sagittal split setback osteotomy with rigid internal fixation or wire fixation were quite small. The ratio was 1:1 in the long term and by trend slightly lower in the short term. No distinction was seen between the short- and long-term ratios for mentolabial fold. The ratio was found to be 1:1 for the mentolabial fold to point B. In the short term, the ratio of the soft tissue pogonion to the pogonion showed a 1:1 ratio, with a trend to be lower in the long term. The upper lip showed mainly protrusion, but the amount was highly variable. This systematic review shows that evidence-based conclusions on soft tissue changes are difficult to draw. This is mostly because of inherent problems of retrospective studies, inferior study designs, and the lack of standardized outcome measurements. Well-designed prospective studies with sufficient samples and excluding additional surgery, ie, genioplasty or maxillary surgery, are needed.

An aqueous H+ permeation pathway in the voltage-gated proton channel Hv1.

Hv1 voltage-gated proton channels mediate rapid and selective transmembrane H(+) flux and are gated by both voltage and pH gradients. Selective H(+) transfer in membrane proteins is commonly achieved by Grotthuss proton 'hopping' in chains of ionizable amino acid side chains and intraprotein water molecules. To identify whether ionizable residues are required for proton permeation in Hv1, we neutralized candidate residues and measured expressed voltage-gated H(+) currents. Unexpectedly, charge neutralization was insufficient to abrogate either the Hv1 conductance or coupling of pH gradient and voltage-dependent activation. Molecular dynamics simulations revealed water molecules in the central crevice of Hv1 model structures but not in homologous voltage-sensor domain (VSD) structures. Our results indicate that Hv1 most likely forms an internal water wire for selective proton transfer and that interactions between water molecules and S4 arginines may underlie coupling between voltage- and pH-gradient sensing.

Visualizing Proton Antenna in a High-Resolution Green Fluorescent Protein Structure

"Proton-collecting antenna" are conjectured to consist of several carboxylates within hydrogen-bond (HB) networks on the surface of proteins, which funnel protons to the orifice of an internal proton wire leading to the protein's active site. Yet such constructions were never directly visualized. Here we report an X-ray structure of green fluorescent protein (GFP) of the highest resolution to date (0.9 A). It allows the identification of some pivotal hydrogen atoms pertinent to uncertainties concerning the protonation state of the chromophore. Applying a computer algorithm for mapping proton wires in proteins reveals the previously observed "active site wire" connecting Glu222 with the surface carboxylate Glu5. In addition, it is now possible to identify what appears to be a proton-collecting apparatus of GFP. It consists of a negative surface patch containing carboxylates, threonines, and water molecules, connected by a HB network to Glu5. Furthermore, we detect exit points via Asn146 and His148 to a hydrophobic surface region. The more extensive HB network of the present structure, as compared with earlier GFP structures, is not accidental. A systematic investigation of over 100 mutants shows a clear correlation between the observed water content of GFP X-ray structures and their resolution. With increasing water content, the proton wires become progressively larger. These findings corroborate the scenario in which the photodissociated proton from wild-type GFP can leak outside, whereafter another proton is recruited via the proton-collecting apparatus reported herein.

Awl versus intravenous cannula stillete in circummandibular wiring—a prospective comparative study

The management of paediatric mandibular fractures using an acrylic splint is a time-tested procedure. Traditionally, an awl is used to place wires to secure such splints. In this article, we have designed prospective study to compare a new technique of using intravenous cannula stillete (IVCS) as against conventional awl in placement of the circummandibular wires. A total of 45 patients were included in the study. Group I included 22 subjects in whom an awl was used, and group II included 23 subjects in whom IVCS was used for placement of circummandibular wires. Parameters such as post-operative pain, swelling and ease of penetration, size of entry and exit wound and injury to adjacent structures were compared. Statistically significant reduction in post-operative pain and swelling were noticed in groupie. The operating surgeons experienced greater ease in using IVCS, and the size of the entry and exit wounds were also relatively small as compared to using an awl. The IVCS, which is disposable, having finer diameter, a sharp bevel and internal wire carrying capacity, clearly demonstrates statistically significant advantages over the usage of a conventional awl.

Soft Tissue Profile Changes After Bilateral Sagittal Split Osteotomy for Mandibular Advancement: A Systematic Review

The purpose of the present systematic review was to evaluate the soft tissue/hard tissue ratio in bilateral sagittal split advancement osteotomy (BSSO) with rigid internal fixation (RIF) or wire fixation (WF). The databases PubMed, Medline, CINAHL, Web of Science, Cochrane Library, and Google Scholar Beta were searched. From the original 711 articles identified, 12 were finally included. Only 3 studies were prospective and 9 were retrospective. The postoperative follow-up ranged from 3 months to 12.7 years for RIF and 6 months to 5 years for WF. The short- and long-term ratios for the lower lip to lower incisor for BSSO with RIF or WF were 50%. No difference between the short- and long-term ratios for the mentolabial-fold to point B and soft tissue pogonion to pogonion could be observed. It was a 1:1 ratio. One exception was seen for the long-term results of the soft tissue pogonion to pogonion in BSSO with RIF; they tended to be greater than a 1:1 ratio. The upper lip mainly showed retrusion but with high variability. Despite a large number of studies on the short- and long-term effects of mandibular advancement by BSSO, the results of the present systematic review have shown that evidence-based conclusions on soft tissue changes are still unknown. This is mostly because of the inherent problems of retrospective studies, inferior study designs, and the lack of standardized outcome measures. Well-designed prospective studies with sufficient sample sizes that have excluded patients undergoing additional surgery (ie, genioplasty or maxillary surgery) are needed.

Magnetohydrodynamic Simulation of Tungsten Wire in Wire‐Array Z Pinch

AbstractThe magnetohydrodynamic behavior of tungsten wire ablating in wire‐array Z pinch discharge on MAGPIE is simulated in a two‐dimensional fine‐grid domain using the GORGON code. A nonideal resistivity model has been implemented in the simulation to obtain plasma transport coefficients in the high density regime along with a screened hydrogenic model to calculate the radiative cooling. Starting from the initial state of warm dense plasma, the evolution of ablated wire is demonstrated to show its explosion and implosion dynamics as a function of discharge time and then the computed profile of electron density is compared with the contour lines reproduced from the measurement by a laser interferometer during the early stage of discharge. The comparison overall shows a fair agreement in terms of the magnitude and the profile shape while some discrepancies can be attributed to the simplified description of the internal wire core physics (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

中空激光光内同轴送丝熔覆工艺的实现及其试验研究

中空激光光内同轴送丝熔覆工艺的实现及其试验研究

A thermo-mechanical model forNb3Sn filaments and wires: strain field for different strand layouts

In Nb3Sn CIC conductors, the superconducting compound is distributed into finefilaments and embedded in a resistive matrix for electrical and thermal stability.Nb3Sn formation requires a solid state diffusion reaction at high temperature, whichcauses an Sn gradient inside the filaments. It is well known that the criticalparameters vary with composition (Sn content) and strain state. In this workthe complete 3D strain field is computed for different wire layouts. First, therelation between the grade of filament reaction and strain is investigated:superconducting wires are studied, taking into consideration non-homogeneousNb3Sn filaments, i.e. considering an unreacted core of pure Nb. Furthermore, the case when thefilaments agglomerate together to give a ‘macrofilament’ is also taken into consideration(internal tin wires).A finite element discretization fine enough to take into consideration non-homogeneousfilaments would result in a very high number of unknowns, which could be beyond thecapacity of today’s computers. Therefore a thermo-mechanical model is formulated, basedon the generalized self-consistent method, suitably developed to deal with the materialnonlinearity and the coupling between the thermal and mechanical fields. In this way,equivalent homogeneous properties are obtained and the analysis of the wires becomesfeasible. An appropriate unsmearing technique finally gives the strain state in the real, nothomogenized, materials.

Urgent Exchange of a HeartMate II Left Ventricular Assist Device After Percutaneous Lead Fracture

In four of our patients implanted with the HeartMate II left ventricular assist device (LVAD), fraying and fracture of the percutaneous lead's internal wires led to pump failure. The patients included two adolescent males (age, 15 and 17 years), one adult male (age, 78 years), and one adult female (age, 49 years). The damage was attributed to patient-related twisting or kinking of the lead. The patients had been supported by the LVAD for 6-18 months before the lead was damaged. In each case, audible and visual alarms were activated, and the pump temporarily continued to function well. The patients were rushed to the hospital, and the pumps were exchanged. All four patients recovered uneventfully and were discharged from the hospital 10-14 days later. They continued to do well on LVAD support for up to 639 days after the initial implant procedure. These events show the importance of educating LVAD patients to avoid excessive twisting or kinking of the device's driveline.

An Audit of Maxillofacial Trauma Patients Treated In a New Tertiary Center in Port-Harcourt, Nigeria

Background: Oral and Maxillofacial surgical care began in the University of Port-Harcourt Teaching Hospital barely 2 years ago. Very little has been known about the pattern of maxillofacial injuries in Port-Harcourt and some neighbouring states in the Niger-Delta region. This audit was undertaken to provide a baseline data on the prevalence and pattern of maxillofacial injuries in this area, to compare the findings with reports from other well researched region of Nigeria, to assess the use of the new facility, and to investigate whether or not the recent increase in the spate of violence in the Niger-Delta region has reflected in the incidence and pattern of maxillofacial injuries treated at the new center. Methodology: Demographic information was collated from the maxillofacial trauma book of the new department of Oral and Maxillofacial surgery at the University of Port-Harcourt. The case record files of patients were retrieved and details about patients, injuries and treatments were collected and analyzed. Results: Thirty nine trauma patients were seen over the two years of existence of the department, The age range was 5-65 years, mean 29.3 + SD 11.8 years, the modal age range was 21-30 years. The male-to-female ratio was 6.8:1. Road traffic crashes accounted for most cause of the injuries [14 VRTA (35.9%) and 11 MVRTA (28.2%)], mandibular fracture was commonest type (51.7%), the average intervention interval was 2 weeks, most cases were treated under local anaesthesia. Intermaxillary fixation was the commonest method of treatment and suffices for all isolated mandibular fractures but was complemented with internal wire suspension and open reduction and internal fixation with interosseous wires in patient with middle third fractures. Conclusion: The pattern of maxillofacial injuries did not differ from what has been reported elsewhere in Nigeria, The new facility was yet to be well patronized probably due to lack of awareness, and there was no reflection of the current increase in violence in the region on the incidence and pattern of maxillofacial injuries seen at the center.

Mapping Proton Wires in Proteins: Carbonic Anhydrase and GFP Chromophore Biosynthesis

We have developed an algorithm for mapping proton wires in proteins and applied it to the X-ray structures of human carbonic anhydrase II (CA-II), the green fluorescent protein (GFP), and some of their mutants. For both proteins, we find more extensive proton wires than typically reported. In CA-II the active site wire exits to the protein surface, and leads to Glu69 and Asp72, located on an electronegative patch on the rim of the active site cavity. One possible interpretation of this observation is that positively charged, protonated buffer molecules dock in that area, from which a proton is delivered to the active site when the enzyme works in the dehydration direction. In GFP we find a new internal proton wire, in addition to the previously reported wire involved in excited state proton transfer. The new wire is located on the other face of the chromophore, and we conjecture that it plays a role in chromophore biosynthesis that occurs following protein folding. In the last step of this process, transient carbanion formation was suggested to occur on the bridge carbon [Pouwels et al. Biochemistry 2008, 47, 10111]. Residues on the new wire (Thr62, His181, Arg96) may participate in proton abstraction from this bridge carbon atom. A possible mechanism involves a rotation of the Thr62 side chain and completion of a short wire by which the proton is transported to His181, while the negative charge is transferred to the imidazolone carbonyl, producing a homoenolate intermediate that is stabilized by Arg96. Finally, comparison of the proton wires in the two proteins reveals common motifs, such as short internalized Ser/Thr-Glu hydrogen-bonded pairs for ultrafast proton abstraction, and threonine side chain rotation functioning as a proton wire switch.

The key role of twist pitch and mechanical pre-treatment in the transport properties of Nb 3Sn wires subject to bending strain

In modelling the transport properties of multi-filamentary Nb 3Sn strands, the knowledge of the geometrical parameters of the superconducting filaments and the electrical and mechanical properties of the different materials composing the wire are required. In particular, the filament twist pitch and the transverse resistivity between filaments have a crucial role in the definition of the current transfer length and, consequently, in the simulation of the transport performances of superconducting wires subject to mechanical loads, as in cable-in-conduit conductors (CICC) for fusion magnets during operation. We have measured the critical current and the n-index of internal tin Nb 3Sn wires with different values of the filament twist pitch, having inserted the strand into a stainless steel jacket and under the application of pure bending strain. Results show that the degradation of the transport properties is affected by the twist pitch value and, in the limit case of non-twisted filaments, even an improvement is observed in presence of bending. Moreover, the reversibility of critical current after relaxing the mechanical load has also been checked and an improvement of the performances has been observed after pre-bending applications, presumably due to the strain relaxation. In addition, the differential analysis through the second derivative of the V– I curve evidenced a peaked critical current distribution for the UNTW-strands, while TW-strands under bending showed a higher degree of non-homogeneity, proven by broader distributions.

Microstructure, composition and critical current density of superconducting Nb 3Sn wires

The production of superconducting Nb 3Sn multifilamentary wires with optimized critical currents requires a detailed knowledge of various processes, involving both the mechanical deformation and the reaction kinetics. The physical properties of the Nb 3Sn phase are briefly reviewed, the precise knowledge of their variation as a function of the Sn content being essential for the optimization of the critical current density, J c. The variation of the transition temperature T c, the upper critical field, B c2(0), and the normal state electric resistivity ρ o, as a function of the Sn content, β, in the binary system Nb 1− β Sn β is carefully analyzed. The effect of Ta, Ti and Ta + Ti additives to Nb 3Sn on the physical properties is discussed in detail. Low temperature specific heat measurements are introduced for determining the T c distribution inside Nb 3Sn filaments while avoiding shielding effects. The microstructure of the superconducting phase in Bronze Route and Internal Sn Diffusion processed wires is studied, taking into account the unique microstructure of Bronze Route filaments, comprising an equiaxed and a columnar grain region, their areas being comparable. The Sn content increases gradually, from 18 to 22 at.% in columnar and from 22 to 25 at.% in equiaxed grains. Taking into account the equiaxed grains only in Bronze Route wires, it is found that the pinning force density F GB is essentially the same as in the superconducting part of Internal Sn and PIT wires. The lower values of the overall F GB in Bronze Route wires is due to the presence of columnar grains, with lower T c and B c2. The presence of columnar grains also explains the deviation from linearity of the Kramer rule in Bronze Route wires. The mechanism leading to the variation of J c vs. ε, where ε is the uniaxial applied strain, is correlated to the elastic tetragonal distortion of the A15 phase in the filaments, caused by the matrix precompression or by Lorentz forces. The behavior of J c ( ε) is found to show systematic differences between Bronze Route and Internal Sn processed wires. Possible reasons for the stronger variation of J c ( ε) up to 21 T in Internal Sn wires are discussed.

35.1: Single Cell‐Gap Transflective FFS LCD Using Wire Grid Polarizer

AbstractA single cell gap and wide‐view transflective LCD using fringe field switching LC cell and an internal wire grid polarizer as reflector is demonstrated. This transflective LCD exhibits a high light transmittance (T) and reflectance (R), and good match between the VT and VR curves.

On optimal ordering of signals in parallel wire bundles

Optimal ordering and sizing of wires in a constrained-width interconnect bundle are studied in this paper. It is shown that among all possible orderings of signal wires, a monotonic order of the signals according to their effective driver resistance yields the smallest weighted average delay. Minimizing weighted average delay is a good approximation for MinMax delay optimization. Three variants of monotonic ordering are proven to be optimal, depending on the Miller coupling factors ( MCF) ratio between the signals at the sides of the bundle and that of the internal wires. The monotonic order property holds for a very broad range of VLSI circuit settings arising in common design practice. A simple, yet near-optimal, setting of wire widths within the bundle to yield the best average weighted delay is proposed. The theoretical results have been validated by numerical experiments on 65 nm process technology and industrial design data. In all cases the ordering optimization yielded improvement in the range of 10% in wire delay, translated to about 5% improvement in the clock cycle of a high-performance microprocessor implemented in that technology.

Transport Properties up to 1000 A of ${\rm Nb}_{3}{\rm Sn}$ Wires Under Transverse Compressive Stress

The effect of transverse compressive stress on the superconducting transport currents of multifilamentary Nb3Sn wires have been measured at 19 T using a newly developed probe allowing gauge lengths as long as 125 mm. Two different wire types have been studied: an experimental Bronze Route wire (from our laboratory) with 14'641 filaments of 4.5 mum diameter and a RRP internal Sn wire (from OST), with 60 filament bundles, each having a diameter of 70 mum. It was found that the RRP wire exhibits higher stress sensitivity. For the Bronze Route wire our data also comprise a comparison of the Ic behavior for rectangular and round cross sections. The problem of current transfer has been solved using a new type of Walters spring (one turn). The spring has been cut parallel to the wire sample into two parts so the measured sample length covers a whole turn. One part can be moved axially and forces up to 40 kN are applicable. The new device will be used for the investigation of various types of superconducting wires, comprising Nb3Sn and Nb3Al, in view of their application in systems with high transverse compressive forces, in particular high field dipoles (e.g. NED).

Grain Growth, Morphology, and Composition Profiles in Industrial ${\hbox{Nb}}_{3}{\hbox{Sn}}$ Wires

The A15 formation process in Nb3Sn wires has been revisited. The progress of the reaction was studied by a careful FE-SEM study after a series of heat treatments at various temperatures and times. It was found that in the very early stage of the reaction, the Sn flow is high and a very thin layer of equiaxed A15 grains is formed at the interface between Nb and the Cu-Sn bronze. Beyond the very first layer with equiaxed grains, the grains form with a columnar shape. With further progress of the A15 layer and the continuous flow of Sn through the already formed layers, a decomposition of the columnar grains to equiaxed grains was observed. By TEM/EDX, we have confirmed our earlier observation of a radial Sn gradient in the filaments. The equiaxed regions have a sufficiently high critical field to carry supercurrents at high magnetic fields, in contrast to the columnar regions, where the B values are lower, thus their contribution to the current transport at the higher fields is limited. We have also studied internal Sn wires and found equiaxed grains only, with a Sn content through the A15 layer reaching from 22 at.% to values close to 25 at.%.