Additional Pins Research Articles

Extension Block Pinning Using a Small External Fixator for Mallet Finger Fractures

To describe surgical outcomes of a series of patients with bony mallet fingers treated by a modified extension blocking technique with external fixation. We developed an external fixator that was attached to the extension block pin. Dorsal rotation of the dorsal fragment during reduction was prevented with 1 or 2 additional pins abutted on the fragment through the fixator. We reviewed 12 consecutive patients with mallet finger fractures who were treated surgically with the external fixator. The mean age of the patients was 33 years (range, 15-60 y). Rotation of the fragment during reduction was well controlled in all patients. All fractures united at an average of 5 weeks after surgery. Average extension lag was 2° and active flexion was 74°. No patient reported pain at a final follow-up of 4 months (range, 3-8 mo). According to the Crawford rating scale, 10 patients were classified as excellent and 2 were good. Our modification of the extension block method prevented dorsal rotation of the fragment during reduction and resulted in early union. Therapeutic IV.

The effect of loading in mechanical response predictions of bone lengthening

Intramedullary (IM) distractor nails have become a viable alternative in bone-distraction operations. Upon stabilization of the fractured/dissected limb via the nail, the resulting construct accommodates the load bearing function of the otherwise healthy limb. In establishing design performance targets for these devices, in vitro test conditions are widely accepted leaving the in vivo conditions aside. However, in vivo device failures due to distraction forces necessitate novel modeling considerations. It is especially important to simulate the loads in limb distraction, as this brings the bone-implant construct to a totally different regime than the hip-joint contact force (Point-Force Model, PFM). In this work we used a simplified approach to incorporate ligament stretching due to limb distraction via self-equilibrating spring elements in a finite-element setting (spring-force model, SFM). We compared the effect of loading type on load transmission paths through the locking pins, for these two distinct loading modes, namely, SFM and PFM. The two modes illustrate entirely different load transfer regimes around the bone/nail interface region. In order to avoid high contact stresses between the nail and the bone segments, it is advisable to keep the osteotomy away from the mid-range between the pin connections. It was also seen for both loading modes that including an additional pin at a load transfer location does not significantly alter the load carried by a single pin (the additional pin rather acts as a geometric stabilizer).

Pin guidance of reconstruction plate contour: An expanded role of external fixation

This article presents a modification of intraoperative external fixation for mandibular reconstruction with free tissue flaps. This technique is indicated when preregistration of the reconstruction plate is not possible due to transmandibular tumor extension. Once standard external fixation has been carried out and prior to segmental mandibulectomy, additional pins are fixed to the connecting rod that delineate the mandibular contour in three-dimensional (3D) space. Following mandibulectomy, these pins allow accurate contouring of the reconstruction plate and improved restoration of mandibular contour, projection, and dental occlusion. A step-by-step description of the technique using models and intraoperative photos is presented. This method of mandibular reconstruction is a simple and time-effective alternative to intraoperative computer navigation and 3D modeling in select cases of oral carcinoma where tumor infiltration of the outer mandibular cortex precludes prebending of the reconstruction plates.

Extraction of artificial boundary frequencies for damage identification

This paper introduces some recent progress in a study which is aimed at incorporating the so-called artificial boundary condition (ABC) frequencies for damage identification. The ABC frequencies are those corresponding to the natural frequencies of the system with additional pin supports, but may be extracted from specially configured incomplete frequency response function matrix of the original structure without the need of physically imposing the additional supports. A particular focus of this paper is placed on the actual extraction of such frequencies from physical experiments and the associated data processing and analysis. Results will demonstrate that it is possible to extract the first few ABC frequencies for a variety of boundary conditions with 1-2 artificial pin supports in a beam or a slab structure.

An Area-Efficient, Low-VDD, Highly Reliable Multi-Cell Antifuse System Fully Operative in DRAMs

A reliable antifuse scheme has been very hard to build, which has precluded its implementation in DRAM products. We devised a very reliable multi-cell structure to cope with the large process variation in the DRAM-cell-capacitor type antifuse system. The programming current did not rise above 564µA even in the nine-cell case. The cumulative distribution of the successful rupture in the multi-cell structure could be curtailed dramatically to less than 15% of the single-cell's case and the recovery problem of programmed cells after the thermal stress (300°C) had disappeared. In addition, we also presented a Post-Package Repair (PPR) scheme that could be directly coupled to the external high-voltage power rail via an additional pin with small protection circuits, saving the chip area otherwise consumed by the internal pump circuitry. A 1Gbit DDR SDRAM was fabricated using Samsung's advanced 50nm DRAM technology, successfully proving the feasibility of the proposed antifuse system implemented in it.

Analysis of Piston Slap Induced Noise and Vibration of Internal Combustion Engine (Effect of Piston Profile and Pin Offset)

This paper presents the analytical method to evaluate the impact force and engine noise induced by piston slap considering the detailed piston profile and dynamic characteristics of the piston. This method was applied to examine the effect of the piston profile and piston pin offset on the piston slap impact force and its induced engine noise. Present numerical method showed that increasing the upper clearance of the piston skirt enlarged the higher frequency components of the piston impact force and engine noise and this was verified by the experimental results. The analysis revealed that piston movement at the vicinity of the combustion top dead center was governed by the friction moment around the piston pin and the additional piston pin offset moment induced by combustion pressure could cancel this friction moment and reduce the piston impact force if the piston pin was offset to the major thrust side. This analytical results was confirmed by the measured results of actual diesel engine.

Exergy analysis of second-generation micro heat sinks under single-phase and flow boiling conditions

A parametric study of exergy efficiency was conducted for five micro pin fin heat sinks of different spacing and shapes. Of the four micro pin fin heat sinks tested under single-phase flow conditions, those with better heat transfer performance yielded superior exergy efficiencies. The use of R-123 in place of water as working fluid was found to enhance exergetic performance at the expense of reduced heat transfer performance. The exergy analysis was also extended to the flow boiling of R-123 in an additional hydrofoil-based micro pin fin heat sink. It was found that exergy efficiencies decreased with mass velocity.

Ostéosynthèse par plaque antérieure verrouillée des fractures complexes de l’extrémité distale du radius: Contribution au maintien de la longueur radiale

Purpose of the study Maintaining radial length, likely to be the main challenge in the treatment of complex distal radius fractures, is necessary for complete grip-strength and pro-supination range recovery. In spite of frequent secondary displacements, bridging external-fixation has remained the reference method, either isolated or in association with additional percutaneous pins or volar plating. Also, there seems to be a relation between algodystrophy and the duration of traction applied on the radio-carpal joint. Fixed-angle volar plating offers the advantage of maintaining the reduction until fracture healing, without bridging the joint. Material and methods In a prospective study, forty-three consecutive fractures of the distal radius with a positivated ulnar variance were treated with open reduction and fixed-angle volar plating. Results were assessed with special attention to the radial length and angulation obtained and maintained throughout treatment, based on repeated measurements of the ulnar variance and radial angulation in the first six months postoperatively. Results The correction of the ulnar variance was maintained until complete recovery, independently of initial metaphyseal comminution, and of the amount of radial length gained at reduction. Only 3 patients lost more than 1 mm of radial length after reduction. The posterior tilt of the distal radial epiphysis was incompletely reduced in 13 cases, whereas reduction was partially lost in 6 elderly osteoporotic female patients. There was 8 articular malunions, all of them less than 2 mm. Secondary displacements were found to be related to a deficient locking technique. Eight patients developed an algodystropy. The risk factors for algodystrophy were articular malunion, associated posterior pining, and associated lesions of the ipsilateral upper limb. Conclusion Provided that the locking technique was correct, this type of fixation appeared efficient in maintaining the radial length in complex fractures of the distal radius. The main challenge remains the reduction of displaced articular fractures. Based on these results, it is not possible to conclude that this method is superior to external fixation.

Pin-retain for restoration of widely tooth damaged

Widely damaged tooth involves enamel as well as dentin could be due to caries or other causes, resulted the preparation of retention could not be fulfilled so that additional pin is used as retention. Pin is made of titanium and used as retention for restoration with the aim to unite restorative material in tooth cavity by filling the hole that is prepared in the dentin. The number of pins that are needed is according to the width of the lost tooth tissue. Restoration with pin functions as retention has conservative advantage to the tooth structure, increases retention, resistance, period of treatment is short, and the cost is cheaper.

Modificações do fixador externo para osteossíntese umeral em pombos domésticos

Este trabalho objetivou avaliar duas modificações no fixador externo para osteossíntese umeral em pombos. Após realização de fratura umeral diafisária, esta foi reduzida com um pino intramedular e outro perpendicular, inserido no segmento distal (Grupo A - GA); no grupo B (GB), utilizou-se um pino adicional no fragmento proximal. Todas as aves foram avaliadas clínica e radiograficamente por 60 dias, exceto quatro de cada grupo, que, aos 15, 22, 29 e 36 dias, foram submetidas a eutanásia, para exame macro e microscópico. Quanto ao vôo, todos os animais avaliados obtiveram êxito, sendo o tempo médio e o desvio padrão de 32.25 ± 6,5 dias no GA e de 39.8 ± 3,83 no GB. Observou-se presença de calo ósseo ao exame radiográfico somente nos animais do GA; o tempo médio e o desvio padrão para a consolidação da fratura foram de 36 ± 0 dias no GA e de 34 ± 3,4 no GB. Os estudos microscópicos revelaram que a consolidação óssea no GB foi mais precoce que no GA. Conclui-se que os fixadores são eficazes, sendo que o com dois pinos promove maior estabilização do sítio da fratura, embora necessite tempo cirúrgico superior para confecção.

Fixation of humeral intercondylar fractures using a lateral plate in 14 dogs supported by finite element analysis of repair

Fourteen Spaniels that presented with an intercondylar fracture of the distal humerus were managed using a lateral plate and an additional pin in twelve cases. Fixation of the fracture was achieved using a plate applied laterally which incorporated the transcondylar lag screw in the most distal hole. Of the 14 cases, two had poor results, one of which was a bilateral case, whilst the remaining 12 cases had good or very good results with only occasional stiffness or lameness. Finite element (FE) modelling of a distal humerus was generated, and loading of fracture repairs using a lateral plate and caudal plate was completed in a comparative study to determine which fixation method resisted micro-motion most effectively. Finite element analysis revealed that the lateral plate fixation provided significantly more resistance to micro movement at the fracture site that the caudal plate fixation, with 40% more micro-motion in the latter.

1.25 Gbit/s ITU-T G.984.2 burst-mode transimpedance amplifier without reset pins

A DC-coupled burst-mode transimpedance amplifier including fast automatic gain control is presented. By employing common-mode level signalling, a reset signal is provided without adding additional package pins. This transimpedance amplifier can be used in the upstream part of ITU-T G.984.2 compliant passive optical networks.

309 ピストンスラップによるエンジン放射音 : ピストンオフセットの影響

This paper presents the analytical method to evaluate the impact force and engine noise induced by piston slap considering the detailed piston profile. This method is applied to examine the effect of the piston profile on piston slap impact force and frequency spectrum related to the engine noise. The tendency of the piston pin offset to abate the piston slap is compared with the measured one to confirm the availability of this method. And it is pointed out that piston movement in the vicinity of the combustion top dead center is governed by the friction moment around the piston pin and the additional piston pin offset moment induced by combustion pressure.

Analysis and design of LC amplifiers and LC oscillators using current-feedback amplifiers

The present paper discusses specific types of LC amplifier and LC oscillator using a current-feedback amplifier (CFA). The main advantage of the CFAs versus voltage-feedback amplifiers (VFAs) is their gain-bandwidth independence. Some of the monolithic CFAs provide an additional pin between the first stage (current-controlled current source) and the second stage (voltage follower), where the resistance is very high. This allows a parallel resonance LC tank to be connected to the additional op amp correction pin. The main advantage of this new configurations is the insignificant influence of the load over the parameters of the circuit (voltage gain, Q-factor, etc.). Some recommendations for designing this kind of analogue circuit are given, based on simulation results, symbol analysis of the transfer function and physical experiments as well as elements’ values calculation using centre frequency, voltage gain, bandwidth and Q-factor of the LC amplifiers as input parameters.

The Use of the Indentation Test for Studying the Solidification Behaviour of Different Semicrystalline Polymers during Injection Molding

AbstractSummary: An in‐line method for monitoring the solidification process during injection molding of semicrystalline polymers (demonstrated previously in J. Appl. Polym. Sci. 2003, 89, 3713) is based on a simple device, where an additional ejector pin is pushed on the injection molded part at different times during the solidification phase. The ‘indentation depth profile’, i.e., residual deformation as a function of time, was obtained and allowed to determine the evolution of the solidification front in the mold as a function of the cooling time. The present work shows the reliability and the powerfulness of the aforementioned method for a large variety of different semicrystalline polymers (PET, PBT, polyamide‐6 PA6, isotactic poly(propylene) iPP) characterized also by different molecular weight and/or nucleating agents. The results show that the indentation test may be considered as a ‘predictive’ tool to qualitatively and quantitatively compare the solidification process of different polymers and polymer grades during injection molding.Comparison of the solid front propagation during injection molding of different materials.imageComparison of the solid front propagation during injection molding of different materials.

Techniques for improving stability in oblique fractures treated by circular fixation with particular reference to the sagittal plane

Biomechanical studies involving all-wire and hybrid types of circular frame have shown that oblique tibial fractures remain unstable when they are loaded. We have assessed a range of techniques for enhancing the fixation of these fractures. Eight models were constructed using Sawbones tibiae and standard Sheffield ring fixators, to which six additional fixation techniques were applied sequentially. The major component of displacement was shear along the obliquity of the fracture. This was the most sensitive to any change in the method of fixation. All additional fixation systems were found to reduce shear movement significantly, the most effective being push-pull wires and arched wires with a three-hole bend. Less effective systems included an additional half pin and arched wires with a shallower arc. Angled pins were more effective at reducing shear than transverse pins. The choice of additional fixation should be made after consideration of both the amount of stability required and the practicalities of applying the method to a particular fracture.

Collective pinning of the vortex lattice by columnar defects in layered superconductors

The mixed phase of layered superconductors with no magnetic screening is studied through a partial duality analysis of the corresponding frustrated $XY$ model in the presence of random columnar pins. A small fraction of pinned vortex lines is assumed. Thermally induced plastic creep of the vortex lattice within isolated layers results in an intermediate Bose glass phase that exhibits weak superconductivity across layers in the limit of weak Josephson coupling. The correlation volume of the vortex lattice is estimated in the strongly coupled Bose glass regime at lower temperature. In the absence of additional point pins, no peak effect in the critical current density is predicted to occur on this basis as a function of the Josephson coupling. Also, the phase transition observed recently inside of the vortex-liquid phase of high-temperature superconductors pierced by sparse columnar defects is argued to be a sign of dimensional crossover.

Modeling an improved method for double modulation photo reflectance experiments

This paper describes an improved method to be used in double modulation photo reflectance experiments, in order to reduce the influence of parasitic effects in the useful signal. The method uses the inner and outer sections of a single chopper disk to modulate the monochromator and the laser beam, eliminating the need of complex electronic filters, and two additional PIN photodiodes for scattered light compensation. The method has been numerically simulated using LabVIEW in order to investigate the influence of the modulator finite switching time and the finite resolution of the digital acquisition system. Results show that a relative error less than 1% can be achieved.

NONPROSTHETIC MANAGEMENT OF PROXIMAL HUMERAL FRACTURES

Many proximal humeral fractures can be treated without the need for hemiarthroplasty. Treatment choice is affected by fracture location and pattern, as well as by patient factors including age, activity level, quality of bone, and ability to comply with a regimen of therapy. Successful diagnosis and treatment of proximal humeral fractures is dependent on good-quality radiographs, but in some cases, intraoperative assessment of the fracture pattern is required for a complete and accurate diagnosis of the fracture pattern and severity. A discussion of nonsurgical and surgical treatment options and techniques needed to achieve anatomic reduction and stable fixation is important.

Indentation test as a tool for monitoring the solidification process during injection molding

AbstractAn inline method for monitoring the solidification process during the injection molding of semicrystalline polymers is demonstrated. The method has been applied to various poly(ethylene terephthalate) (PET) and poly(buthylene terephthalate) (PBT) samples. The technique is based on a simple device by which an additional ejector pin is pushed onto the injection‐molded part with a fixed force at different times during the solidification phase while the mold remains closed. The residual deformation (the so‐called indentation depth) due to the applied load is measured offline after ejection. By the performance of indentation at different times during the cooling phase, an indentation depth profile, that is, the residual deformation as a function of time, is obtained. With a simplified solid/liquid two‐phase model, the evolution of the solidification front in the mold as a function of the cooling time can be determined from the indentation curve. The obtained experimental results agree well with calculations based on the classical theory of heat penetration. Descriptions of several materials (including PET and PBT) with variations in the molecular weight (PET) have been obtained under different operating conditions (various mold temperatures, holding pressures, and indentation pressures). The results show that the indentation test may be regarded as a powerful tool for monitoring the solidification process during injection molding and, therefore, for optimizing injection‐molding processing conditions according to material characteristics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3713–3727, 2003