Segmental Wiring Research Articles

Mechanical loads exerted by different configurations of Burstone’s 3-piece segmented mechanics during a simulated intrusion of the mandibular incisors

Burstone's segmented intrusion arch technique allows variable incisor intrusion with lingual or labial tipping, depending on the position and direction of the force vectors exerted by the intrusion springs. To date, systematic biomechanical studies are lacking. This invitro study aimed to determine the 3-dimensional force-moment systems applied to the 4 mandibular incisors and the deactivation behavior of the appliance by different configurations of the 3-piece intrusion mechanics. The experimental setup consisted of a mandibular model segmented into 2 buccal and 1 anterior segment mounted on a 6-axis Hexapod to simulatedifferent incisor segment malpositions. Active elements were bilateral 0.017 × 0.025-in titanium-molybdenum alloy intrusion springs. Nine geometric appliance configurations at different superpositions of the anterior segment between 4 and 0 mm were evaluated. For 3-mm incisor superposition, mesiodistal variation of the contact of the intrusion spring at the anterior segment wire resulted in labial tipping moments between -0.11 and -1.6 Nmm. Variation of the height of force application at the anterior segment showed no significant influence on the tipping moments. During the simulated intrusion of the anterior segment, a force reduction rate of 21% per mm intrusion was observed. This study contributes to a more detailed and systematic understanding of the 3-piece intrusion mechanics and confirms the simplicity and predictability of the 3-piece intrusion. According to the measured reduction rate, the intrusion springs should be activated once every 2 months or 1-mm intrusion.

Numerical Analysis of Joule Heating in a Ni–Ti Segmented Wire used in Sensing Applications

Numerical Analysis of Joule Heating in a Ni–Ti Segmented Wire used in Sensing Applications

Segmenting electroencephalography wires reduces radiofrequency shielding artifacts in simultaneous electroencephalography and functional magnetic resonance imaging at 7 T.

PurposeSimultaneous scalp electroencephalography and functional magnetic resonance imaging (EEG‐fMRI) enable noninvasive assessment of brain function with high spatial and temporal resolution. However, at ultra‐high field, the data quality of both modalities is degraded by mutual interactions. Here, we thoroughly investigated the radiofrequency (RF) shielding artifact of a state‐of‐the‐art EEG‐fMRI setup, at 7 T, and design a practical solution to limit this issue.MethodsElectromagnetic field simulations and MR measurements assessed the shielding effect of the EEG setup, more specifically the EEG wiring. The effectiveness of segmenting the wiring with resistors to reduce the transmit field disruption was evaluated on a wire‐only EEG model and a simulation model of the EEG cap.ResultsThe EEG wiring was found to exert a dominant effect on the disruption of the transmit field, whose intensity varied periodically as a function of the wire length. Breaking the electrical continuity of the EEG wires into segments shorter than one quarter RF wavelength in air (25 cm at 7 T) reduced significantly the RF shielding artifacts. Simulations of the EEG cap with segmented wires indicated similar improvements for a moderate increase of the power deposition.ConclusionWe demonstrated that segmenting the EEG wiring into shorter lengths using commercially available nonmagnetic resistors is effective at reducing RF shielding artifacts in simultaneous EEG‐fMRI. This prevents the formation of RF‐induced standing waves, without substantial specific absorption rate (SAR) penalties, and thereby enables benefiting from the functional sensitivity boosts achievable at ultra‐high field.

Molar uprighting using a newly designed segmental wire: a case report

Abstract The ectopic eruption path of a permanent molar can cause incomplete emergence through interference by an adjacent tooth, early loss of a primary molar, or an arch length discrepancy. It is clinically important to determine the appropriate appliance that may easily be placed for the considered application of a molar corrective force. A newly designed appliance is introduced for the distal uprighting of an ectopically erupting molar and supported by two case presentations. The current technique of using a segmental wire incorporating double-sided hooks may easily and effectively resolve this problem.

A data-driven method for enhancing the image-based automatic inspection of IC wire bonding defects

Visually inspecting integrated circuit (IC) wire bonding defects is important to ensuring the product quality after the packaging process. The availability of IC X-ray images offers an unprecedented opportunity of studying the image-based automatic IC wire inspection. In this paper, a data-driven method consists of data pre-processing, feature engineering, and classification is developed to address such problem. The data pre-processing is composed of a chip identification algorithm for locating and separating IC chip image patches from the raw images as well as a wire segmentation algorithm for obtaining the wire region. Next, geometric features extracted from the segmented wires are fed into classification models for identifying defects. Five data mining methods are utilised to develop classification models. The vision detection system (VDS) and convolutional neural networks (CNN) are considered as benchmarks. In computational studies, the effectiveness of the developed method is validated by using X-ray images collected from a semiconductor back-end factory in Mainland China. A comparative analysis is conducted to determine the most suitable classifier for the developed method in the chip classification and the SVM model is finally selected. Advantages of the developed method are verified by benchmarking against the VDS and CNN.

Principles of Spine Instrumentation

Introduction : Spinal implants were initially, and are still, used for the supplementation of bony fusion. However, bony fusion operations were initially performed without implants.1 In the US, Wire and screw fixation of the unstable spine techniques remained to use until the pre-World War II years. 20 years after World War II, there were two major breakthroughs in spine surgery: the Harrington system for spine stabilization and deformity correction and the interspinous wiring technique of Rogers. Rogers described the technique of cervical interspinous wiring in the early 1940s. Harrington introduced his instrumentation system in 1962. Discussion : Since then, modifications of both techniques have been devised to increase their security of fixation. The next significant advance in dorsal spinal stabilization was the development of multisegmental spinal instrumentation. Multisegmental instrumentation permits sharing of the load applied to the instrumentation construct with multiple vertebrae, so that decreasing the chance of failure at the metal–bone interface.The Luque segmental wiring technique, developed in the early 1970s, was the first of this class of implants to achieve wide clinical application. Subsequent modifications have been used. Conclusion : Further modifications were the forerunners of more complex, currently used systems of universal spinal instrumentation (USI).

Fast Electromigration Immortality Analysis for Multisegment Copper Interconnect Wires

In this paper, we present a novel and fast electromigration (EM) immortality check for general multisegment interconnect wires. Instead of using current density as the key parameter, as in traditional EM analysis methods based on Black’s equation and the Blech limit, the new method estimates the EM-induced steady-state stress in general multisegment copper interconnect wires based on a novel parameter, Critical EM Voltage , ${V_{\mathrm { Crit,EM}}}$ . We show that the ${V}_{\mathrm { Crit,EM}}$ is essentially the natural, but important, extension of the Blech limit concept, which describes the EM immortality condition for a single segment wire, to more general multisegment interconnect wires. The proposed method, called voltage-based EM (VBEM) method, mitigates the problem of current-density-based EM criteria, which can only be applied to a single wire. The new VBEM method can naturally comprehend the impact of the topology of the wire structure on EM-induced stress. As a result, this new VBEM analysis method is very amenable to addressing EM violations, as it brings new optimization capabilities to the physical design flow. The VBEM stress estimation method is based on the fundamental steady-state stress equations. This approach avoids computationally intensive numerical methods and can be implemented in CAD tools very easily, as we demonstrate on real design examples. We also show that the proposed VBEM analysis method agrees with results from the finite difference method in the steady state through one example and also agrees with one published closed-form expression of steady-state stress for a special 3-terminal wire case. Furthermore, we compare VBEM against the COMSOL finite element analysis tool and another published EM numerical simulator XSim, validated by measured results, which shows that VBEM agrees with both of them very well in terms of accuracy and thus further validates the proposed method. We also study the impact of current crowding in practical interconnect wires on the estimated steady-state stress, which are shown to be not significant if the length of the wire is much greater than its width. An extension of the VBEM method to consider the significant current crowding effects is also shown and additionally, we analyze mesh-structured interconnect wires and demonstrate that the proposed VBEM method is correct and accurate on such structures.

A Generalized Analytical Model for Joule Heating of Segmented Wires

This paper presents an analytical solution for the Joule heating problem of a segmented wire made of two materials with different properties and suspended as a bridge across two fixed ends. The paper first establishes the one-dimensional (1D) governing equations of the steady-state temperature distribution along the wire with the consideration of heat conduction and free-heat convection phenomena. The temperature coefficient of resistance of the constructing materials and the dimension of the each segmented wires were also taken into account to obtain analytical solution of the temperature. COMSOL numerical solutions were also obtained for initial validation. Experimental studies were carried out using copper and nichrome wires, where the temperature distribution was monitored using an IR thermal camera. The data showed a good agreement between experimental data and the analytical data, validating our model for the design and development of thermal sensors based on multisegmented structures.

Resonant Anderson localization in segmented wires.

We discuss a model of random segmented wire, with linear segments of two-dimensional wires joined by circular bends. The joining vertices act as scatterers on the propagating electron waves. The model leads to resonant Anderson localization when all segments are of similar length. The resonant behavior is present with one and also with several propagating modes. The probability distributions evolve from diffusive to localized regimes when increasing the number of segments in a similar way for long and short localization lengths. As a function of the energy, a finite segmented wire typically evolves from localized to diffusive to ballistic behavior in each conductance plateau.

Growth and morphological analysis of segmented AuAg alloy nanowires created by pulsed electrodeposition in ion-track etched membranes.

Background: Multicomponent heterostructure nanowires and nanogaps are of great interest for applications in sensorics. Pulsed electrodeposition in ion-track etched polymer templates is a suitable method to synthesise segmented nanowires with segments consisting of two different types of materials. For a well-controlled synthesis process, detailed analysis of the deposition parameters and the size-distribution of the segmented wires is crucial.Results: The fabrication of electrodeposited AuAg alloy nanowires and segmented Au-rich/Ag-rich/Au-rich nanowires with controlled composition and segment length in ion-track etched polymer templates was developed. Detailed analysis by cyclic voltammetry in ion-track membranes, energy-dispersive X-ray spectroscopy and scanning electron microscopy was performed to determine the dependency between the chosen potential and the segment composition. Additionally, we have dissolved the middle Ag-rich segments in order to create small nanogaps with controlled gap sizes. Annealing of the created structures allows us to influence their morphology.Conclusion: AuAg alloy nanowires, segmented wires and nanogaps with controlled composition and size can be synthesised by electrodeposition in membranes, and are ideal model systems for investigation of surface plasmons.

Posterior Spinal Reconstruction with Pedicle Screws, Multiple Iliac Screws and Wisconsin Spinal Wires in a Patient with Neurofibromatosis Scoliosis: A Case Report

A 54-year-old female with neurofibromatosis type 1 presented with progressing truncal shift owing to spinal deformity. On plain radiograph, the Cobb angle was 54 degree in coronal plane. Radiological examinations showed severe dystrophic change with dysplastic pedicles, bony scalloping, neural foraminal widening from dural ectasia. The patient underwent deformity correction and reconstruction surgery from the T9 to the pelvis using multiple iliac screws and Wisconsin interspinous segmental instrumentation by wiring due to maximize fixation points. The postoperative course was uneventful. One-year follow-up radiographs showed a successful curve correction with solid fusion. We report a case of pedicle dysplasia and dystrophic change treated by posterior segmental spinal instrumentation and fusion with help of multiple iliac screws and modified Wisconsin interspinous segmental wiring.

Anthropometric estimation of body height after surgical correction of scoliosis.

To estimate the height loss in 28 patients who had undergone surgery for scoliosis before skeletal maturity. 28 women patients aged 11 to 18 (mean, 15) years underwent Harrington instrumentation, segmental sublaminar wiring, and posterior spinal fusion for idiopathic scoliosis. The patients' mean age at menarche was 13 (range, 10-16) years. Pre- and post-operative radiographs of the spine were taken to determine curve types, the Cobb angle, and the degree of correction. The standing and sitting heights were measured using a flexible steel tape, and the expected standing and sitting heights were derived using formulae. At the final follow up, the mean patient age was 20 (16-32) years. The mean standing height was 155.2 cm and the mean sitting height was 77.4 cm. Using the formulae, the mean expected standing height was 158.4 cm, indicating height loss of 3.2 cm (t=4.6, p=0.0001), and the mean expected sitting height was 79.9 cm, indicating height loss of 2.6 cm (t=3.84, p=0.001). The curve types of the 28 patients were sub-divided as thoracic (n=7), thoracolumbar (n=18), and double major (n=3). Patients with thoracolumbar curves achieved better correction and less loss of standing and sitting heights. Percentage loss of standing and sitting heights were not correlated with the apex of the curve or the degree of correction. Height loss after surgery was acceptable in comparison with height loss associated with progression of scoliosis without surgery.

Effectiveness of surgical versus conservative treatment for symptomatic unilateral spondylolysis of the lumbar spine in athletes: a systematic review protocol

Review question/objective This systematic review aims to determine the effectiveness of surgical fixation, performed after a trial period of conservative management, compared to conservative management only for unilateral spondylolysis in athletes. More specifically, the objectives are: To assess whether surgical fixation compared to conservative management of unilateral spondylolysis allows athletes to return to their regular sport more rapidly. To identify which intervention is more effective in supporting the athlete to resume pre-injury function. Inclusion criteria Types of participants This review will consider studies in which participants are athletes with symptomatic unilateral spondylolysis of the lumbar spine. Athletes will be defined as individuals under the age of 50 competing in regular organised sporting activities. Both professional and amateur athletes will be considered participating in any type of sport. For participants to be included in the review unilateral spondylolysis has to be radiologically diagnosed in athletes with back pain using CT scanning, MRI or by Single-photon Emission Computed Tomography (SPECT) scanning. An inclusive approach will be adopted with respect to the geographical location of studies with participants from all countries and health care settings to be considered. Only studies where participants have first undergone a trial of conservative treatment prior to surgical intervention will be considered, as this is the current recommended practice. Types of intervention and comparators Surgical interventions, which attempt a direct repair of the pars interarticularis, will be considered for this review. Even though direct repair in the form of Buck's Repair is the most widely recommended surgical treatment for spondylolyis, other surgical techniques including segmental wire fixation and pediculolaminar hook screws have also been shown to be effective and will hence be included in the review.Given that this is a rare procedure and that spondylolyis procedures are only completed in specialist spinal surgery units it is likely that the surgeries will only be performed by a highly qualified specialist and therefore no studies will be excluded on the basis of who is performing the surgery. The comparators are the conservative treatments commonly used to treat unilateral spondylolyis in athletes and allow return to sport including, but not limited to rest, activity modification, bracing, lumbar stability exercises, pharmacological treatment and physical therapy. Types of outcomes The primary outcomes of interest in this review are return to sport, length of time before return to sport and level of sporting activity after treatment. With respect to measures of outcomes, a yes/no response will indicate return to sport, which may be gathered by patient observation or report. All objective and subjective measures of time to return to sport and level of post treatment sporting participation/activity level will be considered. Overall function and pain are secondary outcomes for the review.

Nickel segment-length dependent magnetic properties of Au–Ni–Au nanowires at low temperature fabricated by electrochemical deposition

Segmented wires (Au–Ni–Au) were synthesized by electrochemical deposition. Magnetic study was performed at 6kOe field applied parallel to the wire long axis at 300K and 2K. Coercivity (Hc) and saturation magnetization (Ms) as a function of segment length (l) were constant for longer l (5≤l≤10μm) at 300K and 2K. However, a peak in Hc was observed for l=2.4μm at 300K, whereas a decrease in Hc was found for shorter l. Ms followed a decreasing trend with decreasing segment length from 2.4μm to 200nm.

Effects of Segmented Shield Wires on Signal Attenuation of Power-Line Carrier Channels on Overhead Transmission Lines—Part I: Modeling Method

Shield wire segmentation has been used for quite some time as an effective method for reducing transmission-line power losses, with most segmented shield wire applications on extra high-voltage lines utilizing phase-to-phase power-line carrier (PLC) coupling. As transmission system efficiency becomes more of a priority, some utilities may consider applying segmented shield wires to lower voltage lines, such as 115-kV and 230-kV lines, which most often utilize single-phase-to-ground PLC coupling. Thus, knowledge of the effects of segmented shield wires on PLC signal attenuation for various coupling methods would be useful to relay engineers. The purpose of this paper is to present a generalized method to model transmission lines for signal attenuation calculation at PLC frequencies, with special consideration given to shield wire connections. Terminating impedance and phase wire transposition are considered as well. The modeling method presented is validated with field measurements. In a companion paper, signal attenuation results considering the effects of various parameters are analyzed.

Repair of Pars Defects by Segmental Transverse Wiring for Athletes With Symptomatic Spondylolysis

Retrospective study of surgery for spondylolysis patients. To assess clinical outcome of bony union using multislice computed tomography after segmental wiring fixation. How bony union affects surgical outcome of spondylolysis repair is unclear. Forty-four athletes with symptomatic spondylolysis (33 men and 11 women; mean age, 24.2 ± 5.4 years) who underwent segmental wiring fixation were evaluated retrospectively at a mean follow-up of 85 ± 17 months. The level of spondylolysis was L5 in 42 cases, and both L4 and L5 in 2 cases, giving a total of 46 operative levels of vertebrae. Bony union using axial and sagittal reconstruction images of computed tomography, the Japanese Orthopaedic Association (JOA) score for back pain, and complications were reviewed. State of bony union was classified as bilateral union, unilateral union, or nonunion. The total score and the improvement ratio of the JOA score were compared among the 3 groups. Bilateral bony union was obtained in 29 cases (31 of 46 vertebrae, 67.4%). Six cases (13%) showed unilateral union, and 9 cases (19.6%) showed nonunion. JOA score increased significantly after surgery in all groups, average improvement rate was 78.9% in the bilateral group, 63.6% in the unilateral group, and 29.8% in the nonunion group; differences among the 3 groups were significant (P < 0.05). JOA score was significantly higher in the bilateral group than in the other 2 groups. Although symptoms were significantly ameliorated in all groups, the bilateral group showed the greatest improvement ratio in JOA score showing bony union to be an important factor in clinical outcome. However, there were a few exceptional cases with contradictory clinical and radiological outcomes. Thus, further studies are required to gain a better understanding of the other multiple factors affecting clinical outcome after spondylolysis repair.

Spinal tuberculosis in children: Retrospective analysis of 124 patients

Background:There is a paucity of report on spinal tuberculosis in children. We report a retrospective analysis of 124 children with TB spine treated over 30 years.Materials and Methods:We retrospectively reviewed 124 children; of cervical (n=36), cervicothoracic (n=4), thoracic (n=53), and lumbar and lumbosacral tuberculosis (n=31) with no skip or multifocal lesions treated between 1971-2004. The age ranged from 2 to 15 years of age with 28 children less than 5 years of age, 58 were between 6 and 10 years, and 38 were over 10 years, 18 had paraplegia of various degrees. Ninety-one children were treated conservatively, while 33 children were subjected to surgery for focal debridement (n=23), posterior interspinous wiring and cementation (n=4), and posterior instrumentation with rods and segmental wiring (n=14). Triple chemotherapy (isoniazid, streptomycin, and PAS) was given for 18 months (3HSPa, 15Hpa) between 1971 and 1975, and triple or quadruple chemotherapy (isoniazid, rifampicin, ethambutol, or pyrazinamide) after 1976 to 2004 for 12 months (12RHZ or 12 RHZE). Some of the children in the current series belonged to the British MRC conservative study patients. The average duration of followup was 5 years and 8 months (range 1.6-20 years).Results:All children attained healed status and showed neural recovery (n=18). The patients attained healed status at 18 months in the first series and at 12 months in the second series after chemotherapy. Spontaneous intercorporal fusion occurred only in 10 (8.06%) of 124 children. Sagittal curve during growth showed three different patterns: Unchanged, decreased, and increased curves. The residual kyphosis was unavoidable in cases with growth plate damage. Kyphosis increased in cases with wedged monovertebra and fused wedged block vertebra, though it was different at different level.Conclusion:The vertebral reformation and curve correction were possible only through the growth plates. The posterior instrumented stabilization alone could correct and/or prevent progress of the kyphosis. However, for active tuberculosis, posterior instrumented stabilization combined with anterior radical surgery should be reserved only for the advanced tuberculosis with instability, rapid progress of kyphosis, and/or unacceptable pre-existing kyphosis, though there is a new trend of prophylactic posterior instrumentation even for the early tuberculosis.

Effects of mandibular incisor intrusion obtained using a conventional utility arch vs bone anchorage

To compare the dentofacial effects of mandibular incisor intrusion using mini-implants with those of a conventional incisor intrusion mechanic, the utility arch. Twenty-six deep-bite patients were enrolled to one of the two groups. In group 1 the mandibular incisors were intruded using a 0.16 × 0.22-inch stainless-steel segmental wire connected to two mini-implants. In group 2 the mandibular incisor intrusion was performed using a conventional utility arch. Conventional lateral cephalometric radiographs were taken at pretreatment and at the end of intrusion. Thirty landmarks were identified to measure 23 linear and 20 angular measurements. Intragroup comparisons were made using a paired t-test or a Wilcoxon test. Intergroup comparisons were made using a Student's t-test or a Mann-Whitney U-test. The duration of intrusion was 5 months for group 1 and 4 months for group 2. In the implant group, the mean amount of change was 0.4 mm/mo for the incisor tip and 0.3 mm/mo for the center of resistance, and in the utility arch group, the mean amount of change was 0.25 mm/mo for the incisor tip and 0.2 mm/mo for the center of resistance. The mandibular incisors showed an average protrusion of 7° in the implant group and 8° in the utility arch group. Incisor intrusion that was achieved using an implant-supported segmented archwire was no different than the movement achieved with a conventional intrusion utility arch. The only difference between the two methods was in the molar movement.

Animal experiment of periodontal tissue remodeling in application of mini-implant anchorage for incisor intrusion

The aim of the present study is to observe the remodeling of periodontal tissue in application of miniimplant anchorage for incisor intrusion in dogs. Six adult male beagle dogs were used for the experiment. On the buccal site, a mini-implant was placed at the interalveolar septum between the maxillary second incisor and the third incisor on each side. The six maxillary incisors were connected together through the segmental wires and the individual bands were welded by brackets. An intrusive force (120 g) was applied by Ni-Ti coil spring on each side. An animal was sacrificed at the end of 0, 1, 3, 7, 14 and 30 days, respectively, after the activation. X-ray examination, HE staining and receptor activator of nuclear factor-kappa B ligand (RANKL) immunohistochemistry staining were performed afterwards. Then, we found that the periodontal tissue in apical area and crest of ridge remodeled most actively. In addition, the periodontal tissue on the buccal and the lingual sides also remodeled. In conclusion, the incisor teeth were not only intruded vertically but also showed rotation of the crown towards the labial side and the root towards the palatal side, by using mini-implants as anchorage. Besides, if the force applied was excessively large, it would cause apical root resorption. Key words : Anchorage, mini-implant, incisor intrusion, and receptor activator of nuclear factor-kappa B ligand (RANKL).

Design of RFID Sensor-Tag for Wireless Monitoring of SMA-Reinforced Composite Structure

When Shape memory alloy (SMA) wires are embedded in the composite structure with a specific volume fraction, the properties of the resulting hybrid composite structure, which is called SMA-reinforced composite structure, will be reinforced. Some of SMA wires embedded in the composite can be viewed as two electrodes of the capacitor. The deformation of the composite structure will cause change of the capacitor, therefore the segmental SMA wires embedded in the composite may be considered as the self-sensitive element of structure strain monitoring. The measurement circuit monitoring the change of micro capacitor in structure is designed, and it is integrated with radio frequency identification (RFID) technology to compose RFID sensor-tag, and the variation of capacitor is send to the RFID reader wirelessly to form a wireless health monitoring system. Experimental results show that this RFID sensor-tag and its system can be feasibly used in wireless structural health monitoring of SMA-reinforced composite structure.