Enlargement Technique Research Articles

Round window versus cochleostomy technique in cochlear implantation: histologic findings.

Cochleostomy or round window enlargement techniques for cochlear implant electrode insertion result in more abnormal tissue formation in the basal cochlea and are more apt to produce endolymphatic hydrops than round window electrode insertion. Twelve temporal bones from implanted patients were examined under light microscopy and reconstructed with 3-dimensional reconstruction software to determine cochlear damage and volume of neo-ossification and fibrosis after electrode insertion. Amount of new tissue was compared between 3 groups of bones: insertion through the round window (RW), after enlarging the RW (RWE) and cochleostomy (Cochl). The probable role of the electrode was evaluated in each case with hydrops. More initial damage occurred in the Cochl and RWE groups than in the RW group, and the difference was significant between RWE and RW in cochlear segment I (p < 0.026). The volume of new bone in Segment I differed significantly between groups (p < 0.012) and was greater in the RWE group than in either the Cochl or RW groups (post hoc p's < 0.035 and 0.019, respectively). Hydrops was seen in 5 cases, all in the Cochl and RWE groups. Blockage of the duct was because of new tissue formation in 4 of the 5 hydrops cases. With the electrodes in this series, implantation through the RW minimized initial intracochlear trauma and subsequent new tissue formation, whereas the RW extension technique used at the time of these implantations produced the greatest damage. Future studies may clarify whether today's techniques and electrodes will produce these same patterns of damage.

3D objects enlargement technique using an optical system and multiple SLMs for electronic holography

One problem in electronic holography, which is caused by the display performance of spatial light modulators (SLM), is that the size of reconstructed 3D objects is small. Although methods for increasing the size using multiple SLMs have been considered, they typically had the problem that some parts of 3D objects were missing as a result of the gap between adjacent SLMs or 3D objects lost the vertical parallax. This paper proposes a method of resolving this problem by locating an optical system containing a lens array and other components in front of multiple SLMs. We used an optical system and 9 SLMs to construct a device equivalent to an SLM with approximately 74,600,000 pixels and used this to reconstruct 3D objects in both the horizontal and vertical parallax with an image size of 63 mm without losing any part of 3D objects.

Electricity Options and Additional Information

Electricity markets feature a non-storable underlying, which implies the break down of traditional cash-and-carry arguments as well as the well-known spot-forward relationship. We introduce the notion of information premium to describe the influence of future information—such as planned power plant maintenance—on the relationship between forward contracts and the spot market. In a recent paper we designed a statistical test to show the existence of the premia. Here, we examine how the presence of an information premium alters the prices of options on forwards. Also, we apply the technique of enlargement of filtrations to show how to calculate the premium specifically for certain types of information and delivery periods. Furthermore, we illustrate the results in various stylised examples.

Defining the Efficacy of Aortic Root Enlargement Procedures: A Comparative Analysis of Surgical Techniques

BackgroundAortic root enlargement (ARE) procedures are believed to allow implantation of larger valve prostheses; however, little evidence exists to support the specific efficacy of various techniques. MethodsUsing a cadaveric model, 20 adult (72.4 ± 15.3 years) hearts were stratified into 4 groups based on annular diameter: <20 mm, 20-22 mm, 22-24 mm, and >24 mm. Each heart underwent an aortic valve replacement following a Nicks, Manougian, aortoventriculoplasty and modified Bentall procedure, with appropriate reversals between procedures. ResultsAll 4 groups experienced similar increases in annular diameter (P = 0.43) and prosthesis size implanted (P = 0.51) with each enlargement technique. The Nicks, Manougian, modified Bentall and aortoventriculoplasty procedures enlarged the annulus by 0.43 ± 0.45 mm, 3.63 ± 0.95 mm, 0.78 ± 0.65 mm, and 6.08 ± 1.19 mm, respectively (P < 0.001). No significant change in prosthesis size was observed after the Nicks procedure (P = not significant). Increases of 1.3 ± 0.5, 1.3 ± 0.5, and 2.7 ± 0.6 prosthesis sizes were achieved with the Manougian, modified Bentall and aortoventriculoplasty techniques respectively (P < 0.001). ConclusionsARE procedures appear equally efficacious in both small and larger aortic roots. Although all 4 ARE techniques increased the annular diameter, only the Manougian, modified Bentall and aortoventriculoplasty procedures allowed for the implantation of a larger prosthetic valve. The Nicks procedure, which is likely the most commonly performed ARE, does not allow for the implantation of a larger prosthesis. Surgeon preference and patient factors may help in selecting the most appropriate ARE technique, as the modified Bentall and Manougian procedures achieved similar increases in valve size.

Cadaveric Research: Informing Current Heart Surgery Techniques

Cadavers have long been used in the anatomy lab as teaching tools however, they can also provide valuable research that addresses common surgical problems. Aortic root enlargement (ARE) procedures are employed to facilitate the implantation of larger valve prostheses however, published evidence remains largely anecdotal with respect to the specific increases achievable with these techniques. We sought to design a study using a cadaveric model that will allow for a controlled experiment to evaluate the efficacy of commonly employed ARE techniques. We harvested 20 adult hearts and stratified them into four groups based on aortic annular diameter. Each heart underwent a bileaflet mechanical valve implantation following four ARE techniques with the appropriate reversals between procedures. Annular diameters and implanted prosthesis sizes were recorded following each enlargement technique. We performed all four techniques on each heart with little disruption to the remaining aortic root tissue. In light of the study design, each heart served as its own control. We were also able to provide data as to the increases in implanted prosthesis size achieved with the four ARE techniques. Despite the limitations, cadaveric specimens can play a key role in cardiac surgical research. They provide important data for preoperative planning and allow for experimental research without patient risk.Grant Funding Source : Queen Elizabeth II Graduate Scholarship in Science and Technology

Aortic arch enlargement and coarctation repair through a left thoracotomy: significance of ductal perfusion

To analyse the technique of neonatal aortic arch enlargement without cardiopulmonary bypass through a left posterior thoracotomy, as an adjunct to extended resection for Coarctation and severe arch hypoplasia. Ten neonates with coarctation, severe arch hypoplasia and a persistent ductus arteriosus (PDA) were subjected to arch repair through a left posterior thoracotomy. Nine of these patients had associated significant intracardiac anomalies; three of them received pulmonary artery (PA) banding. After exclusion from circulation, the roof of the intervening arch between left carotid and left subclavian was enlarged using a patch. After adequate reperfusion, a classic resection and extended end-to-end anastomosis was performed. Median age and weight were 5.5 (1-10) days and 3.3 (2.2-4.1) kg respectively. The median preoperative arch diameter was 1.07 (0.75-1.32) mm/kg body weight. All patients could be successfully operated with this approach. The non-ischaemic and ischaemic aortic clamp times were 40 (15-68) and 23 (18-32) min, respectively. The median postoperative arch diameter achieved was 1.43 (1.06-1.46) mm/kg body weight. None of the patients had significant gradient early postoperatively. Two patients with recurrent stenosis were successfully treated with balloon dilatation (1) or surgery with cardiopulmonary bypass (CPB) (1). One patient has a corrected gradient of 16 mmHg in the proximal arch which is being observed. The remaining patients are free from stenosis at a median follow-up of 30.1 (13.2-57.8) months. Use of PDA for lower body perfusion allows complex reconstruction of the arch without incurring lower body ischaemia. The extended resection could then be performed without excessive stretch. This modification saves these patients from undergoing a complex arch reconstruction with CPB in the early neonatal period.

Riemann problem for the Born-Infeld system without differential constraints

We consider the Born-Infeld system without differential constraints. Such a situation occurs as soon as the differential constraints are not satisfied at the initial time. In such a case, the Poynting vector is not a conservative variable and the technique of enlargement of systems cannot be applied. In one space dimension the resulting system consists of five conservative equations for which only one Riemann invariant exists. It is fully linearly degenerate but not strictly hyperbolic, nor is it rich. Under a smallness condition on the initial datum of one variable, we prove that the Riemann problem has a unique entropy solution having discontinuities with three separated speeds. It is surprising that the result holds even for initial data lied in non hyperbolic regions.

Combined aortic and mitral ring enlargement in extreme patient-prosthesis mismatch

Introduction: Long-term results after heart valve replacement can be impaired due to relevant patient-prosthesis mismatch (PPM). This can be avoided by ring enlargement even in double valve procedures. We present a case with an annular enlargement technique for combined aortic and mitral valve replacement in a patient with too small annuli.

A technique for diameter enlargement in SiC crystal growth

Abstract The availability of large high-quality silicon carbide (SiC) single crystals is a key issue in the development of the full potential of SiC-based device technology. This paper mainly discusses SiC crystal growth in the graphite crucible with several geometrical structures by using the physical vapor transport method to investigate the influence of graphite crucible structures on SiC crystal diameter enlargement. Metallographic microscopy and X-ray diffraction are applied to the obtained cross-sectional slice of SiC ingot. In a growth run with a crucible structure of cylinder platform seed-holder and additional cone-shaped inner furnace close to the seed crystal, the SiC crystal diameter increases only 4–5 mm and the growth front exhibits a smooth segment of spherical shape; but the diameter of SiC single crystal decreases when the inside diameter of the crucible is close to that of the seed crystal and the angle α between the cone-shaped platform and cylinder platform is larger than 20°. When using the crucible with a cone-shaped platform seed-holder and cone-shaped inner wall, the SiC crystal growth will proceed along the axial direction as well as the radial direction, and the diameter can be enlarged by about 12 mm in a single growth run.

Preparation of Open‐Cage Fullerenes and Incorporation of Small Molecules Through Their Orifices

Open-cage fullerenes can act as hosts for small molecules such as water, nitrogen, or hydrogen, forming endohedral fullerenes. Following a brief summary of carbon, nitrogen, and oxygen insertion in the fullerene framework to form homofullerenes, methods of creating a hole in the fullerene surface are surveyed. Techniques of hole enlargement and the insertion of atoms or molecules through the orifice to form endohedral fullerenes are described. Finally, the possibility of subsequent closure of the hole is considered.

Markov chain modelling of fluidised bed granulation

Fluidised bed granulation (FBG) is a particle size enlargement technique which is widely employed in industry. Modelling of FBG is important in order to understand, control and optimise the process. In literature, population balance modelling (PBM) which is based on population balance equations (PBEs) is a common tool to model the processing of these particulate systems. However, the solution of PBEs is not straightforward except for relatively simple cases. In this paper, Markov chain simulation is introduced in order to model and analyse the particle size enlargement process in fluidised bed granulation where aggregation and breakage occur simultaneously. For the study, the size enlargement process of granules based on glass beads is examined. 10 g PEG (poly ethylene glycol) with 60% concentration is used as the binder for a 200 g batch. The results show that Markov chains are an efficient tool to model the granulation process. Particle size enlargement and the shape of particle size distributions during the granulation process have been estimated within acceptable errors.

Image Enlargement by Lagrange Interpolation

Nowadays, consumer electronics products are popular. Digital cameras have become the necessaries of life. Due to the constraints of memory size or imaging resolution, image enlargement becomes very important in the field of image processing which can raise the effectiveness of displaying or printing image at the resolution higher than imaging. When the disk space for imaging device is limited, the enlargement technique can be used to raise the resolution of small pictures. The main objective of this paper is to scale the images thereby maintaining the quality without visible aliasing or distortion artifact. Interpolation is required in a variety of image processing applications. We use the Lagrange interpolation formula to constitute an interpolation polynomial to describe the tendency of image data and to estimate the unknown data to achieve the image enlargement. We compare the proposed method with existing image processing software, and the experimental results demonstrate that our method can efficiently enlarge the image with less complexity and better visual quality.

Digital Pulley Enlargement Allowing Early Active Motion Following Primary Repair of Flexor Tendons

We present a new technique of pulley enlargement that preserves its continuity without suturing. The principle of this technique is to excise 2 opposite symmetric triangles. For each of these triangles, the incision starts in the middle of the edge of the pulley and ends beyond the middle of its length. The pulley is enlarged over its entire length, both by debridement of the extremities and by plastic deformation. Although this technique precludes complete closure of the digital sheath, it spares the continuity of the pulley and thus allows early active rehabilitation.

하위 레벨 보간을 이용한 손실 정보 추정과 영상 해상도 향상 기법

Image resolution enhancement algorithm is a basic technique for image enlargement and restoration. The main problem is the image quality degradation such as blurring or blocking effects. In this paper, we propose loss information estimation and image resolution enhancement method using low level interpolation method. In the proposed method, loss information is computed by downsampling -interpolation process of obtained low resolution image. We estimate loss information of high resolution image using interpolation of the computed loss information. Lastly, we add up interpolated high resolution image and the estimated loss information which is applied a weight factor. Our experiments obtained the average PSNR 1.4dB which is improved results better than conventional algorithm. Also subjective image quality is more clearness and distinctness. The proposed method may be helpful for various video applications which required improvement of image.

Mandibula wing osteotomy for correction of the mandibular plane: a case report

We report a new technique for vertical enlargement of the inferior border of the mandible.

Design and analysis of multiple parallel-pass condensers

Abstract This paper describes and analyzes a novel design of multiple parallel-pass (MPP) microchannel tube condenser and its applications to automotive A/C systems. A flow distributor concept is introduced in MPP condenser in order to enable parallel flow arrangement in adjacent flow paths. Throughout analysis of two-phase flow and heat transfer processes in MPP condenser, a two-phase zone enlargement technique is developed to enhance condensation heat transfer and reduce pressure drop. Visual observation indicates a more uniform refrigerant quality entering the next cooling pass can be achieved in MPP condenser because superheated vapor through a pass-through hole on flow distributor directly injects into the separated liquid–vapor zone in a header tube. Performance test results show MPP condenser is able to improve heat transfer rate as high as 9.5% while its refrigerant mass flow increases 13.34% when comparing to a benchmark PF condenser.

Methods of Artificial Enlargement of the Training Set for Statistical Shape Models

Due to the small size of training sets, statistical shape models often over-constrain the deformation in medical image segmentation. Hence, artificial enlargement of the training set has been proposed as a solution for the problem to increase the flexibility of the models. In this paper, different methods were evaluated to artificially enlarge a training set. Furthermore, the objectives were to study the effects of the size of the training set, to estimate the optimal number of deformation modes, to study the effects of different error sources, and to compare different deformation methods. The study was performed for a cardiac shape model consisting of ventricles, atria, and epicardium, and built from magnetic resonance (MR) volume images of 25 subjects. Both shape modeling and image segmentation accuracies were studied. The objectives were reached by utilizing different training sets and datasets, and two deformation methods. The evaluation proved that artificial enlargement of the training set improves both the modeling and segmentation accuracy. All but one enlargement techniques gave statistically significantly (p < 0.05) better segmentation results than the standard method without enlargement. The two best enlargement techniques were the nonrigid movement technique and the technique that combines principal component analysis (PCA) and finite element model (FEM). The optimal number of deformation modes was found to be near 100 modes in our application. The active shape model segmentation gave better segmentation accuracy than the one based on the simulated annealing optimization of the model weights.

Surgery of adult bilateral vocal fold paralysis in adduction: history and trends

Bilateral vocal fold paralysis (BVFP) in adduction is characterised by inspiratory dyspnea, due to the paramedian position of the vocal folds with narrowing of the airway at the glottic level. The condition is often life threatening and therefore requires surgical intervention to prevent acute asphyxiation or pulmonary consequences of chronic airway obstruction. Aside from corticosteroid administration and intubation, which are only temporary measures, the standard approach for improving respiration is to perform a tracheotomy. Over the past century, a vast majority of surgical interventions have been developed and applied to restore the patency of the airway and achieve decannulation. Surgeons can generally choose for every individual patient from various well-established treatment options, which have a predictable outcome. An overview of the surgical techniques for laryngeal airway enlargement in BVFP is presented. Included are operative techniques, which have found application in clinical practice, and only to a small extent in purely anatomic or animal studies. The focus is on two major groups of interventions--for temporary and for definitive glottic enlargement. The major types of interventions include the following: (1) resection of anatomical structures; (2) retailoring and displacing the existing structures, with minimal tissue removal; (3) displacing existing structures, without tissue resection; (4) restoration or substitution of the missing innervation of the laryngeal musculature. The single interventions of these four major types have always followed the development of the medical equipment and anaesthesia. At the beginning of the twentieth century, when medicine was unable to counteract surgical infection, endoscopic or extramucosal surgical techniques were dominant. In the 1950s, the microscopic endoscopic laryngeal surgery boomed. At the end of the twentieth century many of the classical endoscopic operations were performed either with the help of surgical lasers alone, or in combination with other interventions.

Validation of a continuous granulation process using a twin-screw extruder

Using twin-screw granulation as particle size enlargement technique, the effect of modifying the screw configuration (number of mixing zones, configuration of kneading block) on granule quality, tablet properties and mixing efficiency was investigated. The amount of oversized agglomerates and yield was significantly influenced by the presence of an extra conveying element at the screw end. Changing the staggering angle of the kneading block significantly affected yield and granule friability. The 90° configuration resulted in a lower yield and granule friability. Disintegration time was the only tablet property significantly influenced by the screw configuration as disintegration was significantly faster when an extra conveying element was placed at the screw end. The influence of tracer addition method (wet vs. dry) on mixing efficiency inside the extruder barrel was investigated by means of different tracers: riboflavin (0.05%) suspended in the granulation liquid and hydrochlorothiazide (2.5%) added separately as powder. Mixing efficiency in function of time and granule size (above and below 1400 μm) was tested using riboflavine sodium phosphate (0.05%) dissolved in the granulation liquid. Since a good mixing efficiency was obtained independent of tracer addition method, tracer solubility, granulation time and granule size, continuous granulation using a twin-screw extruder was identified as a robust process.

New transcatheter techniques for creation or enlargement of atrial septal defects in infants with complex congenital heart disease

To describe a series of 8 consecutive infants (5 with transposition of the great arteries [TGA] and 3 with hypoplastic left heart syndrome [HLHS]) who underwent nonconventional septostomy techniques. For some complex congenital heart defects, an unrestrictive atrial septal defect (ASD) is essential to achieve an adequate cardiac output and/or systemic saturation. In some scenarios, the use of conventional septostomy techniques may be technically difficult, hazardous, and/or ineffective. Use of transhepatic approach, cutting balloons, and radiofrequency perforation with stenting of the atrial septum. The size of the ASD and the oxygen saturation increased in all patients with no major complications. In those with TGA, the ASDs were considered to be of good size at the arterial switch operation. Two of the 3 patients with hybrid palliation for HLHS have developed some degree of obstruction within the interatrial stent over 2-3 months. At surgery, the stents were found to be secured within the septum with one showing significant fibrous ingrowth after uneventful removal. The other had some nonobstructive ingrowth. Creation or enlargement of ASDs in infants using new nonconventional transcatheter techniques is feasible, safe, and effective, at least in the short-to-mid-term follow-up. Infants with TGA seem to benefit the most because the procedure results in satisfactory clinical stability for subsequent early surgical intervention. In infants with HLHS palliated by a hybrid approach, stent implantation to the atrial septum seems to buy enough time to bring them to the phase II safely despite progressive in-stent obstruction.