Restoration Of Shape Research Articles

Analogy between growth of crystals and ferroelectric domains. Application of Wulff construction

In this article we applied a concept of kinetic Wulff plot (v-plot), which was proposed originally for understanding and control of the crystal growth, for characterization of the domain wall motion anisotropy in uniaxial ferroelectrics. Only the minima of v-plot can be obtained by the observation of the convex growth of isolated domains, whereas we can get insight of the v-plot maxima considering the concave growth during shape transformation after domain coalescence. Within this approach we reconstructed experimentally the compete v-plot for lithium niobate and potassium titanyl phosphate crystals. The giant effect of the domain wall velocity dependence on its orientation has been revealed. The effect results in fast restoration of the convex faceted domain shape with the slowest walls after merging. The proposed approach can be used for understanding and control of domain growth during electric field poling by patterned electrodes.

ROLE OF THE TECHNIQUE OF RECONSTRUCTION IN THE PRESERVATION OF THE HERITAGE BUILDINGS

The technique of reconstruction for the demolished parts of heritage buildings is considered as one of the most important issues in the field of preservation. The technique of reconstruction concerns either with the collapsed or destroyed parts of the building or with missed ones in times not far away.Generally, the reconstruction process is the reassembling of the heritage building parts and reconfiguration thereof, wholly or partially, for the purpose of restoration of the original shape of the building. The technique of the reconstruction process is mostly associated with the disasters which may occur to the heritage buildings and cause the destruction thereof, wholly or partially, such as the earthquakes, floods, fires and wars. Such process shall be carried out depending on intensive studies and accurate documents of the building shape and details.The research discusses the technique of reconstruction in the preservation of the heritage buildings, through an analytical descriptive presentation to practical models clarifying the research idea and explanation thereof. The research had discussed several points, the most important ones thereof being the values and standards distinguishing the heritage buildings and the different techniques for preservation of such buildings, and then the research touched on the nature and patterns of the operations for reconstruction of the heritage buildings and the rules and determinants governing them, in addition to, the different trends thereof, by taking practical examples illustrating the techniques of the patterns of the operations for reconstruction of the heritage buildingsThis research is concluded by presenting the most important results achieved which are summed up in that the process for reconstruction of the demolished or collapsed heritage and historical buildings represent the only available means to be resorted to, due to, the collapse of parts of the building in a manner that lets no other option exists there, and it is the optimum technique which ensures continuity of the heritage buildings survival in the architectural and technical details thereof. The reconstruction process must be conducted depending on specialized studies and accurate documents showing the building shape and its different details whenever possible.

210. Comparing and contrasting the clinical utility of sagittal spine alignment classification frameworks: Roussouly vs SRS-Schwab

BACKGROUND CONTEXT For surgical adult spinal deformity (ASD) patients, incorporating restoration of appropriate Roussouly Classificaion shape into surgical planning may improve outcomes. With the introduction and use of the SRS-Schwab ASD classification system, it is important to compare the utility of both classification frameworks as they relate to surgical outcomes. PURPOSE Compare outcomes of surgical ASD patients classified by both Roussouly and Schwab systems. STUDY DESIGN/SETTING Retrospective review of prospective ASD database. PATIENT SAMPLE A total of 515 ASD patients. OUTCOME MEASURES Complications; Health-related quality of life (HRQL): ODI, SF-36 PCS, SRS-22r. METHODS ASD patients with pre- and 2-year postop (2Y) radiographic/HRQL data were grouped by “theoretical” Roussouly type (Type 1: PI 60°) and “current” Roussouly type (1: SS 45°), as published. Means comparison tests assessed outcomes of those that mismatched “theoretical” and “current” types at both pre- and 2Y intervals (mismatched) to those of preoperative mismatched patients that matched at 2-years (matched). Subanalysis assessed outcomes of patients that improved in Schwab modifiers, and patients that both improved in both Schwab modifiers and matched Roussouly type by 2Y. RESULTS Included 515 ASD patients (59±14yrs, 80%F). The overall cohort showed moderate preoperative global and lumbo-pelvic deformity: SVA(64mm±73), PT(25°±11), PI-LL(16°±21). Preoperative breakdown of “current” Roussouly types: Type 1 (10%), Type 2 (54%), Type 3 (24%), Type 4 (12%). Preoperative mismatch between “current” and “theoretical” types was 60%. By 2Y, 16% of patients matched Roussouly types. Matched and Mismatched groups did not differ in rates of reaching MCID for any HRQL metrics by 2Y(all p>0.1). Reop, PJK and complications did not differ between matched and mismatched(all p>0.1), though mismatched patients showed a trend of increased instrumentation failure(17% vs 26%, p=0.080). By 2Y, 28% of patients improved in PT Schwab modifier, 37% in SVA, and 46% in PI-LL. Patients that improved in PT modifier had lower instrumentation failure rates (16% vs 24%) and higher rates of reaching 2Y MCID for ODI (58% vs 48%) and SRS Activity (75% vs 64%) than patients that did not improve. Patients that both Matched Roussouly at 2Y and improved in all Schwab modifiers met MCID for ODI and SRS Activity at higher rates than patients that did not. Roussouly Match patients that improved in Schwab PT met SRS Activity MCID at a higher rate, and had less renal, infection, and neurologic complications than patients that did not. Roussouly Match patients that improved in Schwab SVA also had superior SF-36 scores and fewer cardiopulmonary complications(all p CONCLUSIONS For surgical ASD patients, isolated restoration of sagittal spinal shape per the Roussouly system was not associated with superior clinical outcomes or complications by 2 years. In contrast, improvement in PT, per the SRS-Schwab system, was associated with substantial improvement in low-back disability by 2 years. Collectively, patients that both matched Roussouly sagittal type and improved in Schwab modifiers had superior complication and patient-reported outcomes by 2 years. These results suggest that concurrent consideration of both existing systems may offer utility in establishing optimal realignment targets. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

FLEXIBLE RINGS IN COMPARISON WITH RIGID RINGS IN THE TREATMENT OF FUNCTIONAL TRICUSPID INSUFFICIENCY: TWO DIFFERENT MODELS OF REVERSE REMODELING OF THE RIGHT HEART

Objective. To compare the models of reverse remodeling of the right heart after the tricuspid valve repair with rigid or flexible rings.Material and Methods. During the period from September, 2016 to February, 2018, 308 patients who had indications for intervention on the mitral valve and concomitant tricuspid insufficiency without significant differences in clinical status were randomized into two groups. Patients of both groups underwent intervention on the mitral valve with concomitant tricuspid valve repair by a rigid ring (Rigid group, n=154) or a flexible ring (Flex group, n=154)Results. The perioperative mortality rates were 2.0% in the Rigid group and 2.5% in the Flex group (p=0.504). There was no difference in the pacemaker implantation rate (5.1% vs. 2.6%, p=0.238). Freedom from tricuspid insufficiency recurrence at 12 months follow-up was comparable (96.7% in the Rigid group vs 96.1% in the Flex group, p=0.521). The global systolic function of the right ventricle (fractional change in area, FAC; ejection fraction, EF) significantly increased in both groups (p<0.001 for both group) without significant intergroup differences (p=0.231 for FAC; p=0.156 for EF). Intergroup comparison of the regional systolic function (systolic excursion tricuspid valve, TAPSE; longitudinal velocity of the tricuspid valve, S’) showed that patients of the Flex group had significantly higher increases in the parameters (p<0.001 for TAPSE; p=0.002 for S’).Conclusion. Both types of the devises had low rates of recurrence of tricuspid insufficiency at the midterm follow-up and contributed to the restoration of the global systolic function of the right ventricle. However, the rigid rings due to their design fix the tricuspid valve annulus, which inevitably affects the regional systolic function. In perspective, the flexible rings can function without interfering with the restoration of the natural shape of the tricuspid valve annulus and its uniform contraction during the cardiac cycle, thus ensuring a significant increase in regional systolic function.

Iliosacral Screw Fixation in Patients with Polytrauma

The need to perform iliosacral fixation in patients with polytrauma and unstable pelvic injuries in the acute period of injury is still an unresolved issue. Minimally invasive techniques of pelvis internal fixation allow to perform single step reconstructive surgery in the acute period of the trauma.Purpose — to evaluate the results of minimally invasive acute iliosacral fixation in patients with polytrauma and unstable pelvic injuries.Materials and methods. The authors analyzed treatment outcomes in 105 patients with polytrauma and unstable pelvic injuries after iliosacral screw fixation in acute period. 69 (65.7%) patients had B-type and 36 (34.3%) patients had c-type of unstable pelvic injuries by AO/ASIF classification. Mean age was 35.5±11.7 years. The severity of injury on the ISS scale was 22.5±12.9 points. Ап patients underwent minimally invasive iliosacral fixation with screws in the acute period of the trauma.Results. Patients classified according to the severity of their status as «stable» (n = 50) and «borderline» (n = 26) with stable hemodynamics (SAD 90 mm Hg) underwent minimally invasive iliosacral screw fixation of posterior pelvic ring straight in the anti-shock surgery. Injured classified as «unstable» (n = 15) and «borderline» (n = 14) with unstable hemodynamic parameters (SAD 90 mm Hg), who needed urgent large surgical procedures (laparotomy, thoracotomy et al.), underwent temporary pelvis stabilization by external fixation and/or c-frame, and as the hemodynamic parameters were stabilized iliosacral screw fixation within 48 hours from the moment of injury. The functional pelvis state in 58 patients by S.A. Majeed scale rated 90.7±11.2 points. The quality of life was assessed using the SF-36 questionnaire.Conclusion. Restoration of the anatomical shape of the pelvic ring and its fixation, primarily posterior aspects, in the acute period of trauma allowed to obtain good anatomical and functional treatment outcomes in 94.9% of the patients with polytrauma.

Expert consensus on techniques of navigation-guided reconstruction of jaw defect

Deformities of the maxillofacial region following trauma and ablative surgery are devastating and not uncommon. Reconstruction of such defects is a surgically challenging procedure. Conventionally, reconstruction of the jaw defects lacks pre-operative customized planning and relies heavily on surgeons' experiences to ensure optimum surgical outcomes. The restoration of jaw shape and function has taken precedence after an extensive tumor resection surgery, especially in the current age of technological advancement. Thus, personalized and accurate reconstruction of jaw defects has become a new goal. Computer-assisted surgery especially navigation-assisted surgery has gained popularity of late, in reconstructing deformities and restoring facial symmetry, appearance and function in the maxillofacial region. This technology provides a clearer three-dimensional visualization of the area of interest and its relationship with the adjacent vital structures. With pre-operative virtual surgical planning, it allows more specific and accurate osteotomies, thus reducing the ischemia and total operating times substantially. The risk of complications is also minimized whilst improving the final surgical outcomes. The use of intra-operative navigation system and other computer-assisted surgical techniques in the surgery can significantly improve the precision of the reconstruction of jaw deformities and achieve personalized and functional reconstructive goals while enhancing the patients' quality of life post-operatively. The Society of Oral and Maxillofacial Surgery, Chinese Stomatological Association provides this professional perspective and present treatment protocol for navigation-guided reconstruction of jaw defect to allow standardization of the techniques while promoting its application among the oral and maxillofacial surgeons.

A robust tangent PCA via shape restoration for shape variability analysis

This paper presents a novel method for handling the effects of shape outliers in statistical shape analysis. Usually performed by a variant of classical principal component analysis (PCA), variability analysis may be highly affected by erroneous shapes. Principal components may thus imply aberrant modes, while eigenshapes may not accurately describe variability in a given set of shapes. Our robust analysis is performed using an elastic metric associated with the square-root velocity representation of shapes. This elastic shape analysis allows shape variability to be described with natural and intuitive deformations. The proposed method based on shape outlier detection applies the shape restoration procedure to rectify aberrant shapes. The resultant components are thus obtained from a tangent PCA on the restored database. By performing experiments based on MPEG-7 and HAND databases, we demonstrate that the proposed scheme is effective for shape variability analysis in the presence of outlying shapes. Our method is then compared with two existing schemes for robust data variability analysis: minimum covariance determinant-based PCA and projection pursuit-based PCA.

Efficiency of local application of tranexamic acid during augmentative mammoplasty

Surgical patients are often at risk of bleeding, which in some cases may even require blood components transfusion. In addition, bleeding provokes the hematoma development, which remains a rather common complication in surgery. Despite the fact that specialists apply post­operative blood pressure monitoring, compression therapy and drainage to prevent the development of such complications, hematomas are marked in plastic surgery at 1 — 15 %.The aim — to increase the augmentation mammoplasty surgery effectiveness by reducing perioperative and postoperative blood loss with tranexamic acid topical use.Materials and methods. 29 women to whom the augmentation mammoplasty was performed for the breast shape restoration, were supervised in the period from 2015 to 2018. Patients were divided into 2 groups. In the first group (n = 10) 10 ml of tranexamic acid were additionally introduced into the implant pocket for haemostasis, in the second group (n = 19) tranexamic acid was not used.Results and discussion. All patients completed the in­patient treatment according to the plan and were discharged on the second and third day after surgery. At control of the drainage fluid, the haemorrhagic and serous­haemorrhagic exudate was obtained from 25 to 90 ml per day after the intervention. The volume of the exudate decreased in the first group more rapidly.Conclusions. The tranexamic acid local application allows to reduce the amount of blood loss in the postoperative period, the duration of the drainage systems functioning and, accordingly, reduce the complications risk associated with the presence of drainage and contrapertures.

Comparison of the sustainability of mitral annular dynamics between two semi-rigid annuloplasty devices.

The choice of annuloplasty device is fundamental at the time of mitral valve repair, the goal being to optimally restore the physiological 3-dimensional (3D) structure and dynamics of the mitral annulus (MA). This study evaluated MA dynamics after annuloplasty with 2 different semi-rigid devices. Thirty-three patients eligible for mitral valve repair were selected for annuloplasty with the Physio II ring (Edwards Lifesciences, Irving, CA, USA) (n = 17) or the Memo 3D ring (LivaNova, Saluggia, Italy) (n = 16). MA dynamics were assessed with transoesophageal 3D echocardiography intraoperatively and 1 year after repair. The postoperative changes in the anteroposterior diameter {3.7% [standard deviation (SD) 2.7] vs 1.9% [SD 1.3]; P = 0.013} and in the annular height [27.7% (SD 8.7) vs 18.0% (SD 13.9); P = 0.003] were significantly larger with the Memo 3D ring during the cardiac cycle. The restoration of the saddle shape at baseline was superior with the Physio II ring, defined by a larger systolic annular height-to-commissural width ratio [15.1% (SD 2.3) vs 7.1% (SD 2.4); P < 0.001]. These observations of MA dynamics were sustained after 1 year, shown by a greater anteroposterior extension [5.1% (SD 1.0) vs 1.7% (SD 1.6); P = 0.002] and change in annular height-to-commissural width ratio [15.7% (SD 12.7) vs 3.1% (SD 3.0); P = 0.020] for the Memo 3D ring. There were no significant differences in mitral valve function between the 2 devices. The MA dynamics after annuloplasty with the Physio II and Memo 3D rings demonstrated a better systolic 3D restoration of the saddle shape with the Physio II ring, whereas the saddle-shaped geometry improved significantly with the Memo 3D ring, as a dynamic phenomenon. The Memo 3D ring also showed increased anteroposterior annular mobility and folding dynamics throughout the cardiac cycle. Moreover, the observed differences in MA dynamics between both devices appeared to be sustainable 1 year after ring implantation.

Application of Virtual Reality for Learning the Material Properties of Shape Memory Alloys

A shape memory alloy (SMA) is an alloy which can eliminate deformation at lower temperatures and restore its original shape upon heating. SMAs have been receiving considerable attention in the research field of materials science, and their applications include robotics, automotive, aerospace, and biomedical industries. Observing the SMA’s shaping and restoration processes is important for understanding its working principles and applications. However, the transformation of its crystal structure with temperature can only be seen using special equipment, such as a transmission electron microscope (TEM), which is an expensive apparatus and the operation requires professional skills. In this study, a teaching module is designed using virtual reality (VR) technology and research results of an SMA to show its shape memory properties, shaping and restoration processes, as well as the real-life applications in an immersive and interactive way. A teaching experiment has been conducted to analyze students’ learning effectiveness using the teaching module (the experimental group) compared with that of using real SMA materials as the teaching aids (the control group). Two classes of students in the Department of Materials Science (one as the experimental group and the other as the control group) were selected as the samples by convenience sampling from a university in North Taiwan. The experimental group contained 52 students and the control group contained 70 students. A nonequivalent pretest-posttest design was adopted to explore whether the two groups had a significant difference in learning effectiveness. The experimental results reveal that the teaching module can improve the learning effectiveness significantly (p = 0.001), and the questionnaire results also show that a majority of the students had positive attitudes about the teaching module. They believed that it could increase their learning motivation and help them understand the properties and applications of the SMA.

Spatial Relationship and Functional Relevance of Three Lipid Domain Populations at the Erythrocyte Surface

Red blood cells (RBC) have been shown to exhibit stable submicrometric lipid domains enriched in cholesterol (chol), sphingomyelin (SM), phosphatidylcholine (PC) or ganglioside GM1, which represent the four main lipid classes of their outer plasma membrane leaflet. However, whether those lipid domains co-exist at the RBC surface or are spatially related and whether and how they are subjected to reorganization upon RBC deformation are not known. Using fluorescence and/or confocal microscopy and well-validated probes, we compared these four lipid-enriched domains for their abundance, curvature association, lipid order, temperature dependence, spatial dissociation and sensitivity to RBC mechanical stimulation. Our data suggest that three populations of lipid domains with decreasing abundance coexist at the RBC surface: (i) chol-enriched ones, associated with RBC high curvature areas; (ii) GM1/PC/chol-enriched ones, present in low curvature areas; and (iii) SM/PC/chol-enriched ones, also found in low curvature areas. Whereas chol-enriched domains gather in increased curvature areas upon RBC deformation, low curvature-associated lipid domains increase in abundance either upon calcium influx during RBC deformation (GM1/PC/chol-enriched domains) or upon secondary calcium efflux during RBC shape restoration (SM/PC/chol-enriched domains). Hence, abrogation of these two domain populations is accompanied by a strong impairment of the intracellular calcium balance. Lipid domains could contribute to calcium influx and efflux by controlling the membrane distribution and/or the activity of the mechano-activated ion channel Piezo1 and the calcium pump PMCA. We currently investigate whether this contribution results from lipid domain biophysical properties.

Our First experience of Using Biodegradable Implants in Latarjet – Bristow Surgical Procedure at Chronic Posttraumatic Anterior Shoulder Insta

Background. Multi-layer spiral computed tomography shows that the main cause of shoulder instability is glenoid cavity bone defect. The aim of our research was to assess the effectiveness and safety of biodegradable implants in the treatment of patients with chronic posttraumatic anterior shoulder instability under conditions of bone defect of glenoid cavity margin by the restoration of anatomic shape and structure of scapula articular surface.Materials and methods. We performed a pilot study based on the results of surgical treatment of 7 patients using 4.5 mm biodegradable compressing screws. In preoperative period, all patients had standard two-dimensional X-rays and MSCT with 3D-reconstruction. In postoperative period, all patients had check-up X-ray right after the surgery and MRI in 3 months after the surgery.Results. The results of the treatment were assessed by common clinical criteria, functional criteria, X-ray evidence and intraand postoperative complications. We registered strong functioning of an arm and an increase in the range of motions. Data from Rowe/Zarins and DASH questionnaires showed that the patients totally recovered. X-ray evidence showed consolidation of non-free autograft to the zone of scapula bone defect without osteolysis or widening of a drilled hole. We did not observe either a failure of union, or any formation of false joint, or any screw fractures in bone tissue. Beyond that, we did not observe any complication in postoperative period and early postoperative complications in particular.Conclusion. Pilot study with use of modern biodegradable implants in osteoplastic stabilization of shoulder joint at recurring instability showed their effectiveness and safety in patients of young and active working age. However, considering small number of patients in pilot study we cannot extrapolate our results to all similar and analogue cases of using biodegradable implants. In this regard, it is necessary to perform major multicenter clinical randomized study for further long-term observation and detection of possible unwanted side effects.

Cranioplasty of Calvarial Skull Defects: A Comparative Study between Using Three Dimensional Custom-Made Cranioprostheses versus Hand-Made Bone Cement in Restoring Skull Configuration

Introduction: Cranioplasty is the surgical repair of a bony defect or deformity in the skull that is caused after cranial surgery or trauma. It carries cosmetic and protective benefits. Many types of materials are allowed. The subject of this study is to compare the outcome of two different manufacturing processes in reconstruction of calvarial skull defects by using 3D custom-made cranioprostheses versus hand-made bone cement implants. Patient and Methods: This is a prospective comparative study conducted on 20 patients of calvarial skull defects of different etiologies, sites and sizes, admitted in the neurosurgical departments of Cairo and Fayoum Universities in the period from August 2017 to February 2018. Patients are divided into two study groups: (group 1) 10 patients operated upon by 3D custom-made implant; (group 2) operated upon by hand-made bone cement implant. Statistical Analysis Used: Mann-Whitney test and Chi-square test. Results: Craniotomy using 3D custom-made implants gives better results than using bone cement in the functional restoration of skull shape and cranial protection with shorter operative time and less rate of postoperative complications. There is no statistically significant difference between the two study groups regarding cosmetic outcome. Conclusion: 3D custom-made implant is recommended for large and complex skull defects. Further and large studies might be needed.

All-Optical Control of Shape.

Photoresponsive liquid crystal elastomers (LCEs) are a unique class of anisotropic materials capable of undergoing large-scale, macroscopic deformations when exposed to light. Here, surface-aligned, azobenzene-functionalized LCEs are prepared via a radical-mediated, thiol-acrylate chain transfer reaction. A long-lived, macroscopic shape deformation is realized in an LCE composed with an o-fluorinated azobenzene (oF-azo) monomer. Under UV irradiation, the oF-azo LCE exhibits a persistent shape deformation for >72 h. By contrasting the photomechanical response of the oF-azo LCE to analogs prepared from classical and m-fluorinated azobenzene derivatives, the origin of the persistent deformation is clearly attributed to the underlying influence of positional functionalization on the kinetics of cis→trans isomerization. Informed by these studies and enabled by the salient features of light-induced deformations, oF-azo LCEs are demonstrated to undergo all-optical control of shape deformation and shape restoration.

Treatment of rhinophyma using a copper vapor laser

Background. Rhinophyma is considered to be the most severe stage of rosacea, associated with the proliferation of the nose skin epithelium, hyperproduction of the sebaceous glands and telangiectasia.The treatment of rhinophyma remains a difficult task. One of the problems associated with rhinophyma is thickened and lumpy skin, penetrated with telangiectasias. The use of laser radiation in the treatment of rhinophyma seems to be promising, since this method allows blood vessels to be selectively heated.For the first time, we describe the treatment of rhinophyma using a copper vapour laser (CVL) equipped with a computerized scanner.Patient description. A 63-year-old male with Fitzpatrick skin type II was treated using an CVL (‘Yakhroma-med' model, RaS P. N. Lebedev Physical Institute). The clinical manifestations of the disease were typical of the phymatous or hypertrophic rhinophyma type, including significant thickening of the tissues and an uneven roughness of the skin surface. The treatment was carried out using a radiation wavelength of 578 nm, exposure duration of 0.2 s and energy exposure (fluence) of 15-30 J/cm2. Operational parameters used for the CVL in the scanner mode were the average power of 0.6-1.2 W and the focusing size of the light spot on the skin of 0.6 mm. The hexagonal mode of the scanning head was used with a maximum size of 12 mm and 1 mm distance between the centres of the laser spots. The treatment resulted in the restoration of the natural nose shape without redness. No side effects were noted.Conclusion: CVL radiation provided a selective photodisruption of the vessels with increased diameter.Due to the remodelling of the vasculature, the described method showed excellent results in the treatment of rhinophyma without side effects.

The Amount of Proximal Lumbar Lordosis Is Related to Pelvic Incidence.

Given that the pelvis is the pedestal on which the spine lies, its morphology has been observed to be associated with specific sagittal spinal shapes and should therefore be taken into account when dealing with pathologic conditions of the spine. However, the exact relationship between the pelvic morphology and lumbar lordosis still remains poorly defined. We hypothesized that the shape of the lumbar lordosis and its relationship with the pelvis could be described using anatomic parameters, independently of posture. (1) What is the variation of lumbar segmental lordosis in an asymptomatic adult population? (2) Is there an association between increasing magnitude of pelvic incidence (PI) and segmental lordosis? (3) How does the position of the apex of lordosis change with increasing magnitude of PI value? This retrospective study used data drawn from a longitudinally maintained database; between March 2014 and January 2015, 119 asymptomatic volunteers between 18 and 79 years old were enrolled in the study. Mean age was 51 years; there were 81 women and 38 men. Both segmental and cumulative lordosis were measured and used to describe the shape of the lumbar spine. We defined cumulative lordosis as the angle between L1 and S1, proximal lordosis as the angle between L1 and the superior endplate of L4, and distal lordosis as the angle between the superior endplates of L4 and S1. PI is defined as the angle between the line passing through the center of the femoral head and the center of the sacral endplate and a line perpendicular to the sacral endplate. Pearson's correlation was performed to analyze the relationship among PI, proximal and distal lordosis. Stratification by PI was performed (low, < 45°; average, 45°-60°; and high, > 60°) and the proportions of distal and proximal lordosis were then compared using an analysis of variance test. In the whole cohort, proximal lordosis accounted for 38% of total lordosis, whereas distal lordosis accounted for 62%. PI revealed a positive correlation with proximal lordosis (r = 0.546; p < 0.001). However, there was no correlation with distal lordosis (r = 0.087; p = 0.346). Stratification by PI showed that proximal lordosis increased across PI groups (16.6° [± 10] versus 21.6° [± 9] versus 30.1° [± 9]; p < 0.001), whereas distal lordosis remained relatively constant (34.8° [± 8] versus 36.7° [± 7] versus 35.9° [± 10]; p = 0.581). Apex position was overall more proximal as PI increased (r = -0.199; p = 0.034). Our study demonstrated that PI influences only the proximal part of the lordosis, but not the distal part in an asymptomatic adult population. The proximal part of the lumbar spine had the most variability across individuals and appeared to accommodate to pelvic morphology (incidence). Further studies using a larger cohort size are encouraged not only to refine this relationship, but also to investigate the effect of restoration of normal lordotic shape of the lumbar spine on the functional outcomes after spinal fusion. Our findings may be useful for surgical planning in an era of patient-specific care. The findings suggest that surgeons should aim for a patient-specific lumbar shape rather than simple global lordosis matched to the PI.

Temporal optical memory based on coherent population and two-photon coherence oscillations

We consider the ${F}_{g}=1\ensuremath{\rightarrow}{F}_{e}=1$ transition between the ground and excited hyperfine levels in alkali-metal vapor interacting with $\ensuremath{\sigma}$ linearly polarized control and probe fields whose polarizations can be either parallel or perpendicular to each other. We develop a matrix formulation that allows a solution of the Bloch equations to all orders in the pump and probe Rabi frequencies. Using this formalism, we calculate the steady-state probe absorption spectrum, the coherent population oscillations (CPOs), and two-photon coherence, in the absence (degenerate case) and presence (nondegenerate case) of a longitudinal magnetic field. We then calculate the probe storage when the pump is switched off and on again. We are particularly interested in whether the probe regains its original temporal shape when the pump is switched on again for the case of identical pump and probe frequencies. We show that, in the nondegenerate case, the restored probe does not regain its original shape whereas, in the degenerate case, the original shape is restored. This can be explained by considering the relative magnitudes of the CPOs which do not remember the temporal shape of the probe and the two-photon coherence oscillations which store the probe shape when the pump is switched off, as in electromagnetically induced transparency memories. In the nondegenerate case, the CPOs are much stronger than the two-photon coherence oscillations whereas, in the degenerate case, they are of similar magnitudes. Thus it is the two-photon coherence oscillations that are responsible for the restoration of the temporal shape of the probe in the degenerate case.

Implementing and Quantifying the Shape-Memory Effect of Single Polymeric Micro/Nanowires with an Atomic Force Microscope.

The implementation of shape-memory effects (SME) in polymeric micro- or nano-objects currently relies on the application of indirect macroscopic manipulation techniques, for example, stretchable molds or phantoms, to ensembles of small objects. Here, we introduce a method capable of the controlled manipulation and SME quantification of individual micro- and nano-objects in analogy to macroscopic thermomechanical test procedures. An atomic force microscope was utilized to address individual electro-spun poly(ether urethane) (PEU) micro- or nanowires freely suspended between two micropillars on a micro-structured silicon substrate. In this way, programming strains of 10±1% or 21±1% were realized, which could be successfully fixed. An almost complete restoration of the original free-suspended shape during heating confirmed the excellent shape-memory performance of the PEU wires. Apparent recovery stresses of σmax,app =1.2±0.1 and 33.3±0.1 MPa were obtained for a single microwire and nanowire, respectively. The universal AFM test platform described here enables the implementation and quantification of a thermomechanically induced function for individual polymeric micro- and nanosystems.

Prospective study of fracture calcaneus with Allan’s procedure- bone grafting without implants

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;Calcaneum is usually fractured following high energy axial traumas such is seen in cases of fall from height or road traffic accidents. If not properly managed these fractures can be a cause of prolonged morbidity in the form of pain, stiffness and deformities. We have conducted this prospective study of fracture calcaneum with the method described by Allan et al which constitute of open reduction and bone grafting without any implants. The objective of the was to determine the clinical approach, described by Allan et al for treatment of fracture calcaneum and to discuss in short the results, pitfalls and challenges associated with this.&lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; A prospective study was done on 42 patients who were diagnosed with intra-articular calcaneal fractures depending upon a predefined inclusion and exclusion criteria. All fractures of the study subjects were treated using a lateral approach by Allan’s procedure. Final outcome was assessed on the basis modified Rowe score.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; In this study a total of 42 patients with intra-articular calcaneal fractures and treated by open reduction and bone grafting without any implants were studied. There were 36 men and 6 women. Majority of the patients tolerated the procedure well and most of the patients (95.23%) had a complete or partial restoration of heel shape. Significant residual pain was seen in only 1 (2.38 %) patient. 36 patients (85.71 %) had excellent outcome 5 patients (11.90%) had good and 1 patient (2.38%) had satisfactory outcome&lt;span lang="EN-IN"&gt;. &lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; The management of intra-articular calcaneal fracture by open reduction and bone grafting without any implants give good results with excellent functional outcome. Since no implants are used in this technique this can be a preferable procedure in rural areas and in patients with low socioeconomic status&lt;span lang="EN-IN"&gt;.&lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt; &lt;/p&gt;

Assessing symmetry of zygomatic bone through three-dimensional segmentation on computed tomography scan and “mirroring” procedure: A contribution for reconstructive maxillofacial surgery

PurposeSurgical reconstruction of zygomatic bones in cases of traumatic injuries is a frequent event: assessment of symmetry is mandatory for a correct restoration of zygomatic shape, but the literature is discordant about its quantification. The purpose of this study is to show a novel method for assessing symmetry of zygomatic bone through mirroring of 3D models segmented on CT-scan. Materials and methodsA total of 100 patients (50 male and 50 female), divided into two age groups (18–49 years and 50–92 years) were selected from the computed tomography (CT) scan database of a hospital in northern Italy. Zygomatic bones from each patient were segmented, and the left bone was automatically mirrored and registered on the right one according to the least point-to-point distance between the two surfaces. The mean and root mean square (RMS) distance between the two models was then calculated. Statistically significant differences according to sex and age groups were assessed through two-way analysis of variance (p < 0.05). In addition, the effect size of differences was calculated. ResultsThe method proved to be repeatable, with inter- and intraoperator errors lower than 5%. Overall, mean and RMS point-to-point distances were respectively 0.01 mm and 0.84 mm, without statistically significant differences according to sex or age (p > 0.05), and with negligible effect size. ConclusionThis study provides an innovative method for assessing the symmetry of the zygomatic bone based on surface analysis. Results may provide useful indications for the reconstruction of zygomatic bones in maxillofacial surgery.