Nonlinear dynamic response and stability analysis of the stapes reconstruction in human middle ear

Stapes fracture causes hearing loss and instability in the middle ear hearing system(MEHS). The material used in the stapes reconstruction restores stapes, but the effects of the nonlinear material parameters on the stability of the MEHS are still unknown. To address this challenge, the nonlinear dynamic response and stability of the stapes reconstruction are investigated using a multi-degree-of-freedom mechanical model. The material parameters of the implant are tentatively determined by analyzing the natural frequencies of the undamped system. The dynamical properties of the MEHS are characterized under different external excitations. The approximate solution of the MEHS near the resonant frequency is derived through the multiple-time-scale method(MTSM). The results show that the nonlinear stiffness of the material has little influence on the MEHS in the healthy state, but it causes resonant phenomena between the ossicle and the implant in the pathological state.

Kinetic equilibrium reconstruction with internal safety factor profile constraints on EAST tokamak

Reconstruction of plasma equilibrium plays an important role in the analysis and simulation of plasma experiments. The kinetic equilibrium reconstruction with pressure and edge current constraints has been employed on EAST tokamak. However, the internal safety factor(q) profile is not accurate. This paper proposes a new way of incorporating q profile constraints into kinetic equilibrium reconstruction. The q profile is yielded from the Polarimeter Interferometer(POINT)reconstruction. Virtual probes containing information on q profile constraints are added to inputs of the kinetic equilibrium reconstruction program to obtain the final equilibrium. The new equilibrium produces a more accurate internal q profile. This improved method would help analyze EAST experiments.

Variational Reconstruction and Simulation Experiments of Sea Surface Wind Field for Ocean Data Buoy

The sea surface wind field is an important physical parameter in oceanography and meteorology.With the continuous refinement of numerical weather prediction,air-sea interface materials,energy exchange,and other studies,three-dimensional(3D)wind field distribution at local locations on the sea surface must be measured accurately.The current in-situ observation of sea surface wind parameters is mainly achieved through the installation of wind sensors on ocean data buoys.However,the results obtained from this single-point measurement method cannot reflect wind field distribution in a vertical direction above the sea surface.Thus,the present paper proposes a theoretical framework for the optimal inversion of the 3D wind field structure variation in the area where the buoy is located.The variation analysis method is first used to reconstruct the wind field distribution at different heights of the buoy,after which theoretical analysis verification and numerical simulation experiments are conducted.The results indicate that the use of variational methods to reconstruct 3D wind fields is significantly effective in eliminating disturbance errors in observations,which also verifies the correctness of the theoretical analysis of this method.The findings of this article can provide a reference for the layout optimization design of wind measuring instruments in buoy observation systems and also provide theoretical guidance for the design of new observation buoys in the future.

Isogeometric Analysis of Hyperelastic Material Characteristics for Calcified Aortic Valve

This study explores the implementation of computed tomography(CT)reconstruction and simulation techniques for patient-specific valves,aiming to dissect the mechanical attributes of calcified valves within transcatheter heart valve replacement(TAVR)procedures.In order to facilitate this exploration,it derives pertinent formulas for 3D multi-material isogeometric hyperelastic analysis based on Hounsfield unit(HU)values,thereby unlocking foundational capabilities for isogeometric analysis in calcified aortic valves.A series of uniaxial and biaxial tensile tests is executed to obtain an accurate constitutive model for calcified active valves.To mitigate discretization errors,methodologies for reconstructing volumetric parametric models,integrating both geometric and material attributes,are introduced.Applying these analytical formulas,constitutive models,and precise analytical models to isogeometric analyses of calcified valves,the research ascertains their close alignment with experimental results through the close fit in displacement-stress curves,compellingly validating the accuracy and reliability of the method.This study presents a step-by-step approach to analyzing themechanical characteristics of patient-specific valves obtained fromCT images,holding significant clinical implications and assisting in the selection of treatment strategies and surgical intervention approaches in TAVR procedures.

Roux-en-Y versus BillrothⅠreconstruction after distal gastrectomy for gastric cancer:A meta-analysis

AIM:To conduct a meta-analysis to compare Rouxen-Y(R-Y) gastrojejunostomy with gastroduodenal Billroth Ⅰ(B-Ⅰ) anastomosis after distal gastrectomy(DG) for gastric cancer.METHODS:A literature search was performed to identify studies comparing R-Y with B-Ⅰ after DG for gastric cancer from January 1990 to November 2012 in Medline,Embase,Science Citation Index Expanded and the Cochrane Central Register of Controlled Trials in The Cochrane Library.Pooled odds ratios(OR) or weighted mean differences(WMD) with 95%CI were calculated using either fixed or random effects model.Operative outcomes such as operation time,intraoperative blood loss and postoperative outcomes such as anastomotic leakage and stricture,bile reflux,remnant gastritis,reflux esophagitis,dumping symptoms,delayed gastric emptying and hospital stay were the main outcomes assessed.Meta-analyses were performed using RevMan 5.0 software(Cochrane library).RESULTS:Four randomized controlled trials(RCTs) and 9 non-randomized observational clinical studies(OCS) involving 478 and 1402 patients respectively were included.Meta-analysis of RCTs revealed that R-Y reconstruction was associated with a reduced bile reflux(OR 0.04,95%CI:0.01,0.14;P < 0.00 001) and remnant gastritis(OR 0.43,95%CI:0.28,0.66;P = 0.0001),however needing a longer operation time(WMD 40.02,95%CI:13.93,66.11;P = 0.003).Metaanalysis of OCS also revealed R-Y reconstruction had a lower incidence of bile reflux(OR 0.21,95%CI:0.08,0.54;P = 0.001),remnant gastritis(OR 0.18,95%CI:0.11,0.29;P < 0.00 001) and reflux esophagitis(OR 0.48,95%CI:0.26,0.89;P = 0.02).However,this reconstruction method was found to be associated with a longer operation time(WMD 31.30,95%CI:12.99,49.60;P = 0.0008).CONCLUSION:This systematic review point towards some clinical advantages that are rendered by R-Y compared to B-Ⅰ reconstruction post DG.However there is a need for further adequately powered,welldesigned RCTs comparing the same.

Comparison between uncut Roux-en-Y and Roux-en-Y reconstruction after distal gastrectomy for gastric cancer: A meta-analysis

AIM To compare uncut Roux-en-Y(U-RY) gastrojejunostomy with Roux-en-Y(RY) gastrojejunostomy after distal gastrectomy(DG) for gastric cancer.METHODS A literature search was conducted in Pubmed, Embase, Web of Science, Cochrane Library, Science Direct, Chinese National Knowledge Infrastructure, Wanfang, and China Science and Technology Journal Database to identify studies comparing U-RY with RY after DG for gastric cancer until the end of December 2017. Pooled odds ratio or weighted mean difference with 95% confidence interval was calculated using either fixed-or random-effects models. Perioperative outcomes such as operative time, intraoperative blood loss, and hospital stay; postoperative complications such as anastomotic bleeding, stricture and ulcer, reflux gastritis/esophagitis, delayed gastric emptying, and Roux stasis syndrome; and postoperative nutritional status(serum hemoglobin, total protein, and albumin levels) were the main outcomes assessed. Metaanalyses were performed using RevM an 5.3 software.RESULTS Two randomized controlled trials and four nonrandomized observational clinical studies involving 403 and 488 patients, respectively, were included. The results of the meta-analysis showed that operative time [weighted mean difference(WMD):-12.95; 95%CI:-22.29 to-3.61; P = 0.007] and incidence of reflux gastritis/esophagitis(OR: 0.40; 95%CI: 0.20-0.80; P = 0.009), delayed gastric emptying(OR: 0.29; 95%CI: 0.14-0.61; P = 0.001), and Roux stasis syndrome(OR: 0.14; 95%CI: 0.04-0.50; P = 0.002) were reduced; and the level of serum albumin(WMD: 0.71; 95%CI: 0.24-1.19; P = 0.003) was increased in patients undergoing U-RY reconstruction compared with those undergoing RY reconstruction. No differences were found with respect to intraoperative blood loss, hospital stay, anastomotic bleeding, anastomotic stricture, anastomotic ulcer, the levels of serum hemoglobin, and serum total protein. CONCLUSION U-RY reconstruction has some clinical advantages over RY reconstruction after DG.

A novel technique of three-dimensional reconstruction segmentation and analysis for sliced images of biological tissues

A novel technique of three-dimensional (3D) reconstruction, segmentation, display and analysis of series slices of images including microscopic wide field optical sectioning by deconvolution method, cryo-electron microscope slices by Fou-rier-Bessel synthesis and electron tomography (ET), and a series of computed tomography (CT) was developed to perform si-multaneous measurement on the structure and function of biomedical samples. The paper presents the 3D reconstruction seg-mentation display and analysis results of pollen spore, chaperonin, virus, head, cervical bone, tibia and carpus. At the same time, it also puts forward some potential applications of the new technique in the biomedical realm.

Preliminary analysis of reactivity reconstruction capability based on inverse kinetics method under different initial reactivity states

Online reactivity monitoring plays an important role in operation and safety analyses of fission reactor systems. The inverse kinetics method, which is based on a point kinetics model, is the most widely used method for reactivity reconstruction of critical water reactors. However, this method is seldom applied to the reactivity reconstruction of subcritical reactors. In this study, an inverse kinetics method was employed for the reactivity reconstruction of a lead-based reactor under different initial reactivity states(ρ_0= 0,-2786,-5486,-8367, and-12,371 pcm). The results showed that the deviation in the reactivity of the lead-based subcritical reactor was greater when ρ_0 became smaller. The reactivity reconstructed using the inverse kinetics method was globally underestimated. At a given reactivity perturbation, the relative and absolute errors increased with the decrease in the initial reactivity. At a given initial reactivity, with the increase in the reactivity perturbation, the absolute error increased, whereas the relative error remained the same.This deviation is due to the variation in the external neutron source, spatial-spectral effects, and sub-diffusive effects, which require further study.

Derivation and Analysis of A New Reconstruction Formula from Cone－beam Projections

A new method to compute the first derivative of 3-DRadon transform is given for cone-beam data taken from any orbit.Smith and Grangeat even derived cone-beam inversion formulaswhich are the basic work in fully 3-D image reconstruction algorithm andare used extensively now. In thispaper we will give a new inversion formula and a simple necessaryand sufficient condition which guarantees the complete reconstructionalgorithm.

Three-Dimensional Finite Elemental Analysis of Bone Stress near an Implant Placed at the Border between Mandible and Fibular Graft in Mandibular Reconstruction

Purpose: The aim of the present study was to use finite elemental analysis (FEA) to evaluate bone stress near an implant placed at the border between the mandible and fibular graft in mandibular reconstruction. Materials and Methods: A fibular model (FM) and transplantation model (TM) were constructed for FEA. In TM, mandible was on the mesial side and the fibular graft was on the distal side. The implant was positioned at the center of both bone models. In TM, it was placed on the border between the mandible and fibular graft. A 10-mm implant was used in the monocortical model and a 15-mm implant was used in the bicortical model. The loading force was set at 100 N, the angle was set at 90°, and the loading position was set as center, mesial, or distal on the upper surface of the prosthesis. Von Mises equivalent stress values of the bone near the implant collar and apex at the middle line between buccal and lingual side were measured. Results: In all models, stress values were significantly lower with center loading than with distal loading and mesial loading. In center loading, the stress values were significantly lower in the bicortical model than in the monocortical model. There were no significant differences in stress values between FM and TM in all conditions. Conclusions: Bone stress was least with the center loading position, which was further decreased by bicortical fixation. There was no increase in mechanical stress associated with placing an implant at the border between the mandible and the fibular graft.

The Functional Analysis on the Reconstruction of the Interpersonal Coherence in E-C Translation Teaching

The interpersonal coherence reconstruction will be applied into the translation study sample intending to explore those coherence features the translator represents in the version, aiming to find out how those coherence features as well as the significance of the coherence reconstruction be presented by analyzing the translation sample. It may shed new light on the application of dis? course coherence to translation teaching and study at interpersonal level.

Assessment of first-order-moment-based sample reconstruction method for design flood estimation in changing environment

Estimating the design flood under nonstationary conditions is challenging. In this study, a sample reconstruction approach was developed to transform a nonstationary series into a stationary one in a future time window (FTW). In this approach, the first-order moment (EFTW) of an extreme flood series in the FTW was used, and two possible methods of estimating EFTW values in terms of point values and confidence intervals were developed. Three schemes were proposed to analyze the uncertainty of design flood estimation in terms of sample representativeness, uncertainty from EFTW estimation, and both factors, respectively. To investigate the performance of the sample reconstruction approach, synthesis experiments were designed based on the annual peak series of the Little Sugar Creek in the United States. The results showed that the sample reconstruction approach performed well when the high-order moment of the series did not change significantly in the specified FTW. Otherwise, its performance deteriorated. In addition, the uncertainty of design flood estimation caused by sample representativeness was greater than that caused by EFTW estimation.

3D Face Reconstruction from a Single Image Using a Combined PCA-LPP Method

In this paper, we proposed a combined PCA-LPP algorithm toimprove 3D face reconstruction performance. Principal component analysis(PCA) is commonly used to compress images and extract features. Onedisadvantage of PCA is local feature loss. To address this, various studies haveproposed combining a PCA-LPP-based algorithm with a locality preservingprojection (LPP). However, the existing PCA-LPP method is unsuitable for3D face reconstruction because it focuses on data classification and clustering.In the existing PCA-LPP, the adjacency graph, which primarily shows the connectionrelationships between data, is composed of the e-or k-nearest neighbortechniques. By contrast, in this study, complex and detailed parts, such aswrinkles around the eyes and mouth, can be reconstructed by composing thetopology of the 3D face model as an adjacency graph and extracting localfeatures from the connection relationship between the 3D model vertices.Experiments verified the effectiveness of the proposed method. When theproposed method was applied to the 3D face reconstruction evaluation set,a performance improvement of 10% to 20% was observed compared with theexisting PCA-based method.

Mechanical analysis of the femoral neck dynamic intersection system with different nail angles and clinical applications

BACKGROUND The femoral neck dynamic intersection system(FNS)is mechanically more stable than other internal fixation techniques.Current studies have confirmed that the structural design of FNS has good biomechanical properties in European and American populations.However,whether the suitability of the FNS's 130°main nail angle design for Asian populations has been thoroughly investigated remains unclear.AIM To compare the biomechanical stability differences among different main nail angles of the FNS in the treatment of femoral neck fractures in Asian populations.METHODS Computed tomography data of the femur of healthy adult male volunteers were imported into Mimics software to create a three-dimensional model of the femur.The model was adapted to the curve using Geomagic software and imported into Solidworks software to construct the Pauwels I femoral neck fracture model and design the FNS internal fixation model using different main nail angles.Afterward,the models were assembled with the FNS fracture model and meshed using the preprocessing Hypermesh software.Subsequently,they were imported into Abaqus software to analyze and evaluate the biomechanical effects of different angles of the FNS main nail on the treatment of femoral neck fractures.RESULTS The peak displacement of the proximal femur under different angles of FNS fixation under stress was 7.446 millimeters in the 120°group and 7.416 millimeters in the 125°group;in the 130°,135°,and 140°FNS fixation groups,the peak displacement was 7.324 millimeters,8.138 millimeters,and 8.246 millimeters,respectively.In the 120°and 125°FNS fixation groups,the maximum stresses were concentrated at the main nail and the anti-rotation screw,which intersected the fracture line of the femur neck,resulting in peak stresses of 200.7 MPa and 138.8 MPa,respectively.Peak stresses of 208.8 MPa,219.8 MPa,and 239.3 MPa were observed on the angular locking plate distal to the locking screw in the 130°,135°,and 140°fixation groups.CONCLUSION FNS has significant stress distribution properties,a minimal proximal femoral displacement,and an optimal stability for treating femoral neck fractures in Asian populations when performed with a 130°main nail angle.

PCA-based 3D Shape Reconstruction of Human Foot Using Multiple Viewpoint Cameras

This paper describes a multiple camera-based method to reconstruct the 3D shape of a human foot. From a foot database, an initial 3D model of the foot represented by a cloud of points is built. The shape parameters, which can characterize more than 92% of a foot, are defined by using the principal component analysis method. Then, using ＂active shape models＂, the initial 3D model is adapted to the real foot captured in multiple images by applying some constraints （edge points＇ distance and color variance）. We insist here on the experiment part where we demonstrate the efficiency of the proposed method on a plastic foot model, and also on real human feet with various shapes. We propose and compare different ways of texturing the foot which is needed for reconstruction. We present an experiment performed on the plastic foot model and on human feet and propose two different ways to improve the final 3D shapers accuracy according to the previous experiments＇ results. The first improvement proposed is the densification of the cloud of points used to represent the initial model and the foot database. The second improvement concerns the projected patterns used to texture the foot. We conclude by showing the obtained results for a human foot with the average computed shape error being only 1.06 mm.

A rapid micro-magnetic resonance imaging scanning for three-dimensional reconstruction of peripheral nerve fascicles

The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual workload and poor image registration. Micro-magnetic resonance imaging（Micro-MRI）, an emerging radiology technique, has been used to report results in the brain, liver and tumor tissues. However, micro-MRI usage for obtaining intraneural structures has not been reported. The aim of this study was to present a new imaging method for three-dimensional reconstruction of peripheral nerve fascicles by ~1T micro-MRI. Freshly harvested sciatic nerve samples from an amputated limb were divided into four groups. Two different scanning conditions（Mannerist Solution/GD-DTPA contrast agent, distilled water） were selected, and both T1 and T2 phases programmed for each scanning condition. Three clinical surgeons evaluated the quality of the images via a standardized scale. Moreover, to analyze deformation of the two-dimensional image, the nerve diameter and total area of the micro-MRI images were compared after hematoxylin-eosin staining. The results show that rapid micro-MRI imaging method can be used for three-dimensional reconstruction of the fascicle structure. Nerve sample immersed in contrast agent（Mannerist Solution/GD-DTPA） and scanned in the T1 phase was the best. Moreover, the nerve sample was scanned freshly and can be recycled for other procedures. MRI images show better stability and smaller deformation compared with histological images. In conclusion, micro-MRI provides a feasible and rapid method for three-dimensional reconstruction of peripheral nerve fascicles, which can clearly show the internal structure of the peripheral nerve.

Grain production space reconstruction and land system function tradeoffs in China

Grain production space reconstruction referred to the changes in the quantity,quality and pattern of grain produc-tion space caused by functional tradeoffs and conflicts between grain production space,urban-rural development space,and ecological service space.Exploring tradeoffs between land system functions caused by grain produc-tion space reconstruction was particularly important for ensuring food security,promoting the construction of ecological civilization,and achieving sustainable development.Therefore,this study identified four relationships of land system functions during the process of grain production space reconstruction(1980-2018)in China by using Set Pair Analysis.Research results showed that the reconstruction of grain production space was achieved mainly through three pathways:Grain for Green,deforestation and reclamation,and urban expansion.Generally,ecological service had spatial negative correlation with grain production,economic development and population carrying capacity(P<0.01),but grain production,economic development and population carrying capacity were positively correlated with each other(P<0.01).In the process of grain production space reconstruction,eco-logical services and economic development,ecological services and population carrying capacity had all shown inverse synergies;there was a tradeoffbetween grain production and ecological services,a codirectional tradeoffbetween grain production and economic development,but a strong synergy between economic development and population carrying capacity.However,the functions of land systems only appeared as synergies or tradeoffs,and there were no inverse synergies and codirectional tradeoffs in the separate processes of Grain for Green,deforestation and reclamation,and urban expansion.It can be concluded that the relationships between land system functions were relatively simple in a single process,but it became complex and diverse when multiple processes were integrated for system analysis.

Pouch Roux-en-Yvs No Pouch Roux-en-Y following total gastrectomy:a meta-analysis based on 12 studies

After a total resection of the stomach, the continuity of the gastrointestinal tract can be restored either by Rouxen-Y esophagojejunostomy with or without a pouch. There is still no consensus on the best reconstruction technique. The aim of this report was to derive a more precise estimation of Roux-en-Y esophagojejunostomy with a pouch compared with Roux-en-Y esophagojejunostomy without a pouch. Studies were identified by PubMed and Embase searches, and the inclusion criteria were randomized controlled trials （RCTs） comparing reconstruction techniques between Roux-en-Y with and without a pouch. A total of 12 studies including 1,018 patients were included. The meta-analysis shows that pouch Roux-en-Y does not significantly increase total postoperative complications, anastomotic leakage or mortality, hnportantly, there is no significant difference in S-year survival rates between the two groups. Patients with Roux-en-Y esophagojejunostomy complained significantly less of reflux symptoms and dumping syndrome, and had significantly less severe reflux esophagitis. Quality of life was significantly improved in patients with Roux-en-Y esophagojejunostomy with a pouch compared with patients who received Roux-en-Y reconstruction without a pouch. The results indicate the need for Roux-en-Y esophagojeju- nostomy with a pouch is a gastric substitute after total gastrectomy by comparison with Roux-en-Y esophagojejunostomy without a pouch.