BACKGROUND For patients with advanced gastric cancer,surgical resection remains the main treatment option.Total gastrectomy combined with radical resection of gastric cancer lesions and sentinel lymph nodes can signif...BACKGROUND For patients with advanced gastric cancer,surgical resection remains the main treatment option.Total gastrectomy combined with radical resection of gastric cancer lesions and sentinel lymph nodes can significantly prolong the survival of patients.Digestive tract reconstruction after total gastrectomy is essential to maintain gastrointestinal function and optimize postoperative recovery.Therefore,it is very important to choose a suitable reconstruction method to improve the quality of life of total gastrectomy patients.AIM To evaluate the effects of different digestive tract reconstruction methods in gastric cancer patients undergoing total gastrectomy.METHODS This retrospective study included 172 patients who underwent total gastrectomy for gastric cancer at The First Hospital of Hebei Medical University for analysis.The patients were categorized into two groups:Group A,consisting of 90 patients who underwent modified Roux-en-Y gastrojejunostomy,and group B,consisting of 82 patients who underwent uncut Roux-en-Y gastrojejunostomy.The general patient characteristics,perioperative indicators,postoperative gastrointestinal mucosal barrier function,nutritional status,immunological markers,and occurrence of complications were compared between the two groups.RESULTS Group A showed shorter digestive tract reconstruction time than group B(P<0.05).On the first postoperative day,group A showed lower serum levels of D-lactate,diamine oxidase,and endotoxin than group B(P<0.05).One month postoperatively,group A showed higher prognostic nutritional index,serum albumin,total protein,and body weight than group B(P<0.05).One month postoperatively,the levels of cluster of differentiation(CD)3+,CD4+,and CD8+cells were not significantly different between two groups(P>0.05).The complication rates were 10.00%in group A and 24.39%in group B;group A had a significantly lower complication rate than group B(P<0.05).CONCLUSION Using modified Roux-en-Y gastrojejunostomy during total gastrectomy shortens the time required for gastrointestinal anastomosis,reduces surgery-induced gastrointestinal mucosal damage,and mitigates postoperative declines in nutritional status.展开更多
This overview discusses old and new results as to the controversy on the past glacier extension in High Asia, which has been debated for 35 years now. This paper makes an attempt to come closer to a solution. H.v. Wis...This overview discusses old and new results as to the controversy on the past glacier extension in High Asia, which has been debated for 35 years now. This paper makes an attempt to come closer to a solution. H.v. Wissmann's interpretation (1959) of a small-scale glaciation contrasts with M. Kuhle's reconstruction (1974) of a large-scale glaciation with a 2.4 million km2 extended Qinghai-Xizang (Tibetan) inland glaciation and a Himalaya-Karakorum icestream network. Both opinions find support but also contradiction in the International and Chinese literature (Academia Sinica). The solution of this question is of supraregional importance because of the subtropical position of the concerned areas. In case of large albedo-intensive ice surfaces, a global cooling would be the energetical consequence and, furthermore, a breakdown of the summer monsoon. The current and interglacial heat-low above the very effective heating panel of the Qinghai-Xizang (Tibetan) Plateau exceeding 4000 m, which gives rise to this monsoon circulation, would be replaced by the cold-high of an inland ice. In addition, the plate-tectonically created Pleistocene history of the uplift of High Asia — should the occasion arise up to beyond the snowline (ELA) —would attain a paleoclimatically great, perhaps global importance. In case of a heavy superimposed ice load, the question would come up as to the glacio-isostatic interruption of this primary uplift. The production of the loesses sedimentated in NE-China and their very probable glacial genesis as well as an eustatic lowering of the sea-level by 5 to 7 m in the maximum case of glaciation are immediately tied up with the question of glaciation we want to discuss. Not the least, the problems of biotopes of the sanctuary-centres of flora and fauna, i.e., interglacial re-settlement, are also dependent on it. On the basis of this Quaternary- geomorphological-glaciological connection, future contributions are requested on the past glaciation, the current and glacial permafrost table and periglacial development, the history of uplift, and the development of Ice Age lakes and loess, but also on the development of vegetation and fauna in High Asia.展开更多
BACKGROUND The incidence of gastric cancer has significantly increased in recent years.Surgical resection is the main treatment,but the method of digestive tract reconstruction after gastric cancer surgery remains con...BACKGROUND The incidence of gastric cancer has significantly increased in recent years.Surgical resection is the main treatment,but the method of digestive tract reconstruction after gastric cancer surgery remains controversial.In the current study,we sought to explore a reasonable method of digestive tract reconstruction and improve the quality of life and nutritional status of patients after surgery.To this end,we statistically analyzed the clinical results of patients with gastric cancer who underwent jejunal interposition double-tract reconstruction(DTR)and esophageal jejunum Roux-en-Y reconstruction(RY).AIM To explore the application effect of DTR in total laparoscopic radical total gastrectomy(TLTG)and evaluate its safety and efficacy.METHODS We collected the relevant data of 77 patients who underwent TLTG at the Fourth Hospital of Hebei Medical University from October 2021 to January 2023.Among them,35 cases were treated with DTR,and the remaining 42 cases were treated with traditional RY.After 1:1 propensity score matching,the cases were grouped into 31 cases per group,with evenly distributed data.The clinical characteristics and short-and long-term clinical outcomes of the two groups were statistically analyzed.RESULTS The two groups showed no significant differences in basic data,intraoperative blood loss,number of lymph node dissections,first defecation time after operation,postoperative hospital stay,postoperative complications,and laboratory examination results on the 1st,3rd,and 5th days after operation.The operation time of the DTR group was longer than that of the RY group[(307.58±65.14)min vs(272.45±62.09)min,P=0.016],but the first intake of liquid food in the DTR group was shorter than that in the RY group[(4.45±1.18)d vs(6.0±5.18)d,P=0.028].The incidence of reflux heartburn(Visick grade)and postoperative gallbladder disease in the DTR group was lower than that in the RY group(P=0.033 and P=0.038).Although there was no significant difference in body weight,hemoglobin,prealbumin,and albumin between the two groups at 1,3 and 6 months after surgery,the diet of patients in the DTR group was better than that in the RY group(P=0.031).CONCLUSION The clinical effect of DTR in TLTG is better than that of RY,indicating that it is a more valuable digestive tract reconstruction method in laparoscopic gastric cancer surgery.展开更多
The nonuniform distribution of interference spectrum in wavenumber k-space is a key issue to limit the imaging quality of Fourier-domain optical coherence tomography(FD-OCT).At present,the reconstruction quality at di...The nonuniform distribution of interference spectrum in wavenumber k-space is a key issue to limit the imaging quality of Fourier-domain optical coherence tomography(FD-OCT).At present,the reconstruction quality at different depths among a variety of processing methods in k-space is still uncertain.Using simulated and experimental interference spectra at different depths,the effects of common six processing methods including uniform resampling(linear interpolation(LI),cubic spline interpolation(CSI),time-domain interpolation(TDI),and K-B window convolution)and nonuniform sampling direct-reconstruction(Lomb periodogram(LP)and nonuniform discrete Fourier transform(NDFT))on the reconstruction quality of FD-OCT were quantitatively analyzed and compared in this work.The results obtained by using simulated and experimental data were coincident.From the experimental results,the averaged peak intensity,axial resolution,and signal-to-noise ratio(SNR)of NDFT at depth from 0.5 to 3.0mm were improved by about 1.9 dB,1.4 times,and 11.8 dB,respectively,compared to the averaged indices of all the uniform resampling methods at all depths.Similarly,the improvements of the above three indices of LP were 2.0 dB,1.4 times,and 11.7 dB,respectively.The analysis method and the results obtained in this work are helpful to select an appropriate processing method in k-space,so as to improve the imaging quality of FD-OCT.展开更多
Three-dimensional(3 D)reconstruction of icosahedral viruses has played a crucial role in the development of cryoelectron microscopy single-particle reconstruction,with many cryo-electron microscopy techniques first es...Three-dimensional(3 D)reconstruction of icosahedral viruses has played a crucial role in the development of cryoelectron microscopy single-particle reconstruction,with many cryo-electron microscopy techniques first established for structural studies of icosahedral viruses,owing to their high symmetry and large mass.This review summarizes the computational methods for icosahedral and symmetry-mismatch reconstruction of viruses,as well as the likely challenges and bottlenecks in virus reconstruction,such as symmetry mismatch reconstruction,contrast transformation function(CTF)correction,and particle distortion.展开更多
The ADER approach to solve hyperbolic equations to very high order of accuracy has seen explosive developments in the last few years,including both methodological aspects as well as very ambitious applications.In spit...The ADER approach to solve hyperbolic equations to very high order of accuracy has seen explosive developments in the last few years,including both methodological aspects as well as very ambitious applications.In spite of methodological progress,the issues of efficiency and ease of implementation of the solution of the associated generalized Riemann problem(GRP)remain the centre of attention in the ADER approach.In the original formulation of ADER schemes,the proposed solution procedure for the GRP was based on(i)Taylor series expansion of the solution in time right at the element interface,(ii)subsequent application of the Cauchy-Kowalewskaya procedure to convert time derivatives to functionals of space derivatives,and(iii)solution of classical Riemann problems for high-order spatial derivatives to complete the Taylor series expansion.For realistic problems the Cauchy-Kowalewskaya procedure requires the use of symbolic manipulators and being rather cumbersome its replacement or simplification is highly desirable.In this paper we propose a new class of solvers for the GRP that avoid the Cauchy-Kowalewskaya procedure and result in simpler ADER schemes.This is achieved by exploiting the history of the numerical solution that makes it possible to devise a time-reconstruction procedure at the element interface.Still relying on a time Taylor series expansion of the solution at the interface,the time derivatives are then easily calculated from the time-reconstruction polynomial.The resulting schemes are called ADER-TR.A thorough study of the linear stability properties of the linear version of the schemes is carried out using the von Neumann method,thus deducing linear stability regions.Also,via careful numerical experiments,we deduce stability regions for the corresponding non-linear schemes.Numerical examples using the present simplified schemes of fifth and seventh order of accuracy in space and time show that these compare favourably with conventional ADER methods.This paper is restricted to the one-dimensional scalar case with source term,but preliminary results for the one-dimensional Euler equations indicate that the time-reconstruction approach offers significant advantages not only in terms of ease of implementation but also in terms of efficiency for the high-order range schemes.展开更多
Understanding long-term human-environment interactions requires historical reconstruction of past land-use and land-cover changes. Most reconstructions have been based primarily on consistently available and relativel...Understanding long-term human-environment interactions requires historical reconstruction of past land-use and land-cover changes. Most reconstructions have been based primarily on consistently available and relatively standardized information from historical sources. Based on available data sources and a retrospective research, in this paper we review the approaches and methods of the digital reconstruction and analyze their advantages and possible constraints in the following aspects： （1） Historical documents contain qualitative or semi-quantitative information about past land use, which also usually include land-cover data, but preparation of archival documents is very time-consuming. （2） Historical maps and pictures offer visual and spatial quantitative land-cover information. （3） Natural archive has significant advantages as a method for reconstructing past vegetation and has its unique possibilities especially when historical records are missing or lacking, but it has great limits of rebuilding certain land-cover types. （4） Historical reconstruction models have been gradually developed from empirical models to mechanistic ones. The method does not only reconstruct the quantity of land use/cover in historical periods, but it also reproduces the spatial distribution. Yet there are still few historical land-cover datasets with high spatial resolution. （5） Reconstruction method based on multiple-source data and multidisciplinary research could build historical land-cover from multiple perspectives, complement the missing data, verify reconstruction results and thus improve reconstruction accuracy. However, there are challenges that make the method still in the exploratory stage. This method can be a long-term development goal for the historical land-cover reconstruction. Researchers should focus on rebuilding historical land-cover dataset with high spatial resolution by developing new models so that the study results could be effectively applied in simulations of climatic and ecological effects.展开更多
In this paper, we study the low-complexity channel reconstruction methods for downlink precoding in massive multiple-Input multiple-Output(MIMO) systems. When the user is allocated less streams than the number of its ...In this paper, we study the low-complexity channel reconstruction methods for downlink precoding in massive multiple-Input multiple-Output(MIMO) systems. When the user is allocated less streams than the number of its antennas, the base station(BS) or user usually utilizes the singular value decomposition(SVD) to get the effective channels, whose dimension is equal to the number of streams. This process is called channel reconstruction and done in BS for time division duplex(TDD) mode. However, with the increasing of antennas in BS, the computation burden of SVD is getting incredible. Here, we propose a series of novel low-complexity channel reconstruction methods for downlink precoding in 3D spatial channel model. We consider different correlations between elevation and azimuth antennas, and divide the large dimensional matrix SVD into two kinds of small-size matrix SVD. The simulation results show that the proposed methods only produce less than 10% float computation than the traditional SVD zero-forcing(SVD-ZF) precoding method, while keeping nearly the same performance of 1Gbps.展开更多
A simple,efficient and accurate high resolution method to tracking moving-interfaces-the characteristic integral-averaging finite volume method on unstructured meshes is proposed. And some numerical tests and evaluati...A simple,efficient and accurate high resolution method to tracking moving-interfaces-the characteristic integral-averaging finite volume method on unstructured meshes is proposed. And some numerical tests and evaluation of six main efficient methods for interface reconstruction are made. Through strict numerical simulation,their characters,advantages and shortcomings are compared,analyzed and commended in particular.展开更多
Molecular management is a promising technology to face challenges in the refining industry, such as more stringent requirements for product oil and heavier crude oil, and to maximize the value of every molecule in pet...Molecular management is a promising technology to face challenges in the refining industry, such as more stringent requirements for product oil and heavier crude oil, and to maximize the value of every molecule in petroleum fractions. To achieve molecular management in refining processes, a novel model that is based on structure oriented lumping(SOL) and group contribution(GC) methods was proposed in this study. SOL method was applied to describe a petroleum fraction with structural increments, and GC method aimed to estimate molecular properties. The latter was achieved by associating rules between SOL structural increments and GC structures. A three-step reconstruction algorithm was developed to build a representative set of molecules from partial analytical data. First, structural distribution parameters were optimized with several properties. Then, a molecular library was created by using the optimized parameters. In the final step, maximum information entropy(MIE) method was applied to obtain a molecular fraction. Two industrial samples were used to validate the method, and the simulation results of the feedstock properties agreed well with the experimental data.展开更多
In the process of encoding and decoding,erasure codes over binary fields,which just need AND operations and XOR operations and therefore have a high computational efficiency,are widely used in various fields of inform...In the process of encoding and decoding,erasure codes over binary fields,which just need AND operations and XOR operations and therefore have a high computational efficiency,are widely used in various fields of information technology.A matrix decoding method is proposed in this paper.The method is a universal data reconstruction scheme for erasure codes over binary fields.Besides a pre-judgment that whether errors can be recovered,the method can rebuild sectors of loss data on a fault-tolerant storage system constructed by erasure codes for disk errors.Data reconstruction process of the new method has simple and clear steps,so it is beneficial for implementation of computer codes.And more,it can be applied to other non-binary fields easily,so it is expected that the method has an extensive application in the future.展开更多
Three-dimensional(3D)reconstruction of human organs has gained attention in recent years due to advances in the Internet and graphics processing units.In the coming years,most patient care will shift toward this new p...Three-dimensional(3D)reconstruction of human organs has gained attention in recent years due to advances in the Internet and graphics processing units.In the coming years,most patient care will shift toward this new paradigm.However,development of fast and accurate 3D models from medical images or a set of medical scans remains a daunting task due to the number of pre-processing steps involved,most of which are dependent on human expertise.In this review,a survey of pre-processing steps was conducted,and reconstruction techniques for several organs in medical diagnosis were studied.Various methods and principles related to 3D reconstruction were highlighted.The usefulness of 3D reconstruction of organs in medical diagnosis was also highlighted.展开更多
In ophthalmological practice,eyelid reconstruction is often needed because of the presence of defects that arise after the excision of a tumor or after injuries.Various methods for reconstructing these defects have be...In ophthalmological practice,eyelid reconstruction is often needed because of the presence of defects that arise after the excision of a tumor or after injuries.Various methods for reconstructing these defects have been previously described.However,it is important to understand the basic principles underlying these techniques and their advantages and disadvantages to ensure the choice of the optimal technique in a particular case.We have analyzed the recent literature on new methods or modifications of existing ones to provide a brief overview of the reconstructive methods of the century for comparison.We searched PubMed and CyberLeninka for articles on restoring eyelid defects reported in the literature over the past 10 years.Most techniques can be considered modified classical reconstruction methods.Postoperative complications included aesthetic defects,such as scarring of the upper or lower eyelid,trichiasis,entropion,and lagophthalmos.Surgeons continue to search for the best methods for complex reconstructive surgery to achieve good cosmetic and aesthetic outcomes.展开更多
The accuracy of unstructured finite volume methods is greatly influenced by the gradient reconstruction, for which the stencil selection plays a critical role. Compared with the commonly used face-neighbor and vertex-...The accuracy of unstructured finite volume methods is greatly influenced by the gradient reconstruction, for which the stencil selection plays a critical role. Compared with the commonly used face-neighbor and vertex-neighbor stencils, the global-direction stencil is independent of the mesh topology, and characteristics of the flow field can be well reflected by this novel stencil. However, for a high-aspect-ratio triangular grid, the grid skewness is evident, which is one of the most important grid-quality measures known to affect the accuracy and stability of finite volume solvers. On this basis and inspired by an approach of using face-area-weighted centroid to reduce the grid skewness, we explore a method by combining the global-direction stencil and face-area-weighted centroid on high-aspect-ratio triangular grids, so as to improve the computational accuracy. Four representative numerical cases are simulated on high-aspect-ratio triangular grids to examine the validity of the improved global-direction stencil. Results illustrate that errors of this improved methods are the lowest among all methods we tested, and in high-mach-number flow, with the increase of cell aspect ratio, the improved global-direction stencil always has a better stability than commonly used face-neighbor and vertex-neighbor stencils. Therefore, the computational accuracy as well as stability is greatly improved, and superiorities of this novel method are verified.展开更多
Data collected in two-dimensional projections give planar images of object at each projection angle. To obtain information along the depth of the object, tomographic images are reconstructed using these projections. T...Data collected in two-dimensional projections give planar images of object at each projection angle. To obtain information along the depth of the object, tomographic images are reconstructed using these projections. There are basically two approaches to solve the problem of reconstruction: analytical and iterative, each one presenting its own advantages and limitations. This paper provides a detailed introduction and comparison to four analytical image reconstruction methods including Fourier transformation, simple back-projection, back-projection filtering and filtered back-projection.展开更多
MRSI plays a more and more important role in clinical application. In this paper,we compare several fast MRSI technologies and data reconstruction methods. For the conventional phase encoding MRSI,the data reconstruct...MRSI plays a more and more important role in clinical application. In this paper,we compare several fast MRSI technologies and data reconstruction methods. For the conventional phase encoding MRSI,the data reconstruction using FFT is simple. But the data acquisition is very time consuming and thus prohibitive in clinical settings. Up to now,the MRSI technologies based on echo-planar, spiral trajectories and sensitivity encoding are the fastest in data acquisition,but their data reconstruction is complex. EPSI reconstruction uses shift of odd and even echoes. Spiral SI uses gridding FFT. SENSE-SI,a new approach to reducing the acquisition time,uses the distinct spatial sensitivities of the individual coil elements to recover the missing encoding information. These improvements in data acquisition and image reconstruction provide a potential value of metabolic imaging as a clinical tool.展开更多
Objective To measure the tensile strength of the normal medial patellofemoral ligament(MPFL),and evaluate the biomechanics of different fixation methods of the hamstring tendon graft on the patella.Methods Eight fresh...Objective To measure the tensile strength of the normal medial patellofemoral ligament(MPFL),and evaluate the biomechanics of different fixation methods of the hamstring tendon graft on the patella.Methods Eight fresh cadaver knees were prepared by isolating the patella,leaving only the MPFL as its attachment to the medial condyle of femur.The MPFL was reconstructed by three different methods:four-suture fixation,anchors-single suture fixation,and anchors-double suture fixation.The tensile strength and the elongation of the normal MPFL and the tendon grafts were measured.Results The tensile strength of the four-suture fixation group(234.86±49.02 N)was stronger than that of the normal MPFL(146.91±25.30 N,P=0.0014)and the anchors-single suture group(159.17±49.07N,P=0.0077),while weaker than that of the anchors-double suture group(314.74±78.46 N,P=0.0052)Conclusions With regard to the tensile strength,the four-suture fixation method is reliable for clinical use.Compared with the anchor-suture method,the four-suture fixation method which has no specific implants is more economical,convenient and efficient.展开更多
In this paper, the problem of reconstructing numerical derivatives from noisy data is considered. A new framework of mollification methods based on the L generalized solution regularization methods is proposed. A spec...In this paper, the problem of reconstructing numerical derivatives from noisy data is considered. A new framework of mollification methods based on the L generalized solution regularization methods is proposed. A specific algorithm for the first three derivatives is presented in the paper, in which a modification of TSVD, termed cTSVD is chosen as the regularization technique. Numerical examples given in the paper verify the theoretical results and show efficiency of the new method.展开更多
Total and even partial glossectomy could be a major event in the life of a patient. Tongue function is so complicated which makes maintaining normal functions of the tongue such as swallowing and speech and preserving...Total and even partial glossectomy could be a major event in the life of a patient. Tongue function is so complicated which makes maintaining normal functions of the tongue such as swallowing and speech and preserving larynx integrity after the surgery is a primary objective of the surgeon. This task is very difficult and the result is not predictable. Recent years, however, there has been interesting developments in microsurgical techniques, and these advancements enable oral and maxillofacial surgeons to achieve better results and improve the quality of their patient′s life. The results even with use of the new technology are still far from perfect. Several reasons may cause variation in the result. Some of them have to do with the patient such as general health and other reasons are due to the method that is used and nature of the defect after the removal of the tumor. This article was undertaken to summarize the various methods and techniques used over the years to restore oral tongue functions after defects.展开更多
After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the tim...After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the timing of interventions,combined with the limitations of current methods.To address these challenges,various techniques have been developed to aid in the repair and reconstruction of neural circuits at different stages of injury.Notably,neuromodulation has garnered considerable attention for its potential to enhance nerve regeneration,provide neuroprotection,restore neurons,and regulate the neural reorganization of circuits within the cerebral cortex and corticospinal tract.To improve the effectiveness of these interventions,the implementation of multitarget early interventional neuromodulation strategies,such as electrical and magnetic stimulation,is recommended to enhance functional recovery across different phases of nerve injury.This review concisely outlines the challenges encountered following spinal cord injury,synthesizes existing neurostimulation techniques while emphasizing neuroprotection,repair,and regeneration of impaired connections,and advocates for multi-targeted,task-oriented,and timely interventions.展开更多
文摘BACKGROUND For patients with advanced gastric cancer,surgical resection remains the main treatment option.Total gastrectomy combined with radical resection of gastric cancer lesions and sentinel lymph nodes can significantly prolong the survival of patients.Digestive tract reconstruction after total gastrectomy is essential to maintain gastrointestinal function and optimize postoperative recovery.Therefore,it is very important to choose a suitable reconstruction method to improve the quality of life of total gastrectomy patients.AIM To evaluate the effects of different digestive tract reconstruction methods in gastric cancer patients undergoing total gastrectomy.METHODS This retrospective study included 172 patients who underwent total gastrectomy for gastric cancer at The First Hospital of Hebei Medical University for analysis.The patients were categorized into two groups:Group A,consisting of 90 patients who underwent modified Roux-en-Y gastrojejunostomy,and group B,consisting of 82 patients who underwent uncut Roux-en-Y gastrojejunostomy.The general patient characteristics,perioperative indicators,postoperative gastrointestinal mucosal barrier function,nutritional status,immunological markers,and occurrence of complications were compared between the two groups.RESULTS Group A showed shorter digestive tract reconstruction time than group B(P<0.05).On the first postoperative day,group A showed lower serum levels of D-lactate,diamine oxidase,and endotoxin than group B(P<0.05).One month postoperatively,group A showed higher prognostic nutritional index,serum albumin,total protein,and body weight than group B(P<0.05).One month postoperatively,the levels of cluster of differentiation(CD)3+,CD4+,and CD8+cells were not significantly different between two groups(P>0.05).The complication rates were 10.00%in group A and 24.39%in group B;group A had a significantly lower complication rate than group B(P<0.05).CONCLUSION Using modified Roux-en-Y gastrojejunostomy during total gastrectomy shortens the time required for gastrointestinal anastomosis,reduces surgery-induced gastrointestinal mucosal damage,and mitigates postoperative declines in nutritional status.
文摘This overview discusses old and new results as to the controversy on the past glacier extension in High Asia, which has been debated for 35 years now. This paper makes an attempt to come closer to a solution. H.v. Wissmann's interpretation (1959) of a small-scale glaciation contrasts with M. Kuhle's reconstruction (1974) of a large-scale glaciation with a 2.4 million km2 extended Qinghai-Xizang (Tibetan) inland glaciation and a Himalaya-Karakorum icestream network. Both opinions find support but also contradiction in the International and Chinese literature (Academia Sinica). The solution of this question is of supraregional importance because of the subtropical position of the concerned areas. In case of large albedo-intensive ice surfaces, a global cooling would be the energetical consequence and, furthermore, a breakdown of the summer monsoon. The current and interglacial heat-low above the very effective heating panel of the Qinghai-Xizang (Tibetan) Plateau exceeding 4000 m, which gives rise to this monsoon circulation, would be replaced by the cold-high of an inland ice. In addition, the plate-tectonically created Pleistocene history of the uplift of High Asia — should the occasion arise up to beyond the snowline (ELA) —would attain a paleoclimatically great, perhaps global importance. In case of a heavy superimposed ice load, the question would come up as to the glacio-isostatic interruption of this primary uplift. The production of the loesses sedimentated in NE-China and their very probable glacial genesis as well as an eustatic lowering of the sea-level by 5 to 7 m in the maximum case of glaciation are immediately tied up with the question of glaciation we want to discuss. Not the least, the problems of biotopes of the sanctuary-centres of flora and fauna, i.e., interglacial re-settlement, are also dependent on it. On the basis of this Quaternary- geomorphological-glaciological connection, future contributions are requested on the past glaciation, the current and glacial permafrost table and periglacial development, the history of uplift, and the development of Ice Age lakes and loess, but also on the development of vegetation and fauna in High Asia.
基金Supported by 2024 Government-funded Clinical Medicine Talent Project,No.ZF2024122.
文摘BACKGROUND The incidence of gastric cancer has significantly increased in recent years.Surgical resection is the main treatment,but the method of digestive tract reconstruction after gastric cancer surgery remains controversial.In the current study,we sought to explore a reasonable method of digestive tract reconstruction and improve the quality of life and nutritional status of patients after surgery.To this end,we statistically analyzed the clinical results of patients with gastric cancer who underwent jejunal interposition double-tract reconstruction(DTR)and esophageal jejunum Roux-en-Y reconstruction(RY).AIM To explore the application effect of DTR in total laparoscopic radical total gastrectomy(TLTG)and evaluate its safety and efficacy.METHODS We collected the relevant data of 77 patients who underwent TLTG at the Fourth Hospital of Hebei Medical University from October 2021 to January 2023.Among them,35 cases were treated with DTR,and the remaining 42 cases were treated with traditional RY.After 1:1 propensity score matching,the cases were grouped into 31 cases per group,with evenly distributed data.The clinical characteristics and short-and long-term clinical outcomes of the two groups were statistically analyzed.RESULTS The two groups showed no significant differences in basic data,intraoperative blood loss,number of lymph node dissections,first defecation time after operation,postoperative hospital stay,postoperative complications,and laboratory examination results on the 1st,3rd,and 5th days after operation.The operation time of the DTR group was longer than that of the RY group[(307.58±65.14)min vs(272.45±62.09)min,P=0.016],but the first intake of liquid food in the DTR group was shorter than that in the RY group[(4.45±1.18)d vs(6.0±5.18)d,P=0.028].The incidence of reflux heartburn(Visick grade)and postoperative gallbladder disease in the DTR group was lower than that in the RY group(P=0.033 and P=0.038).Although there was no significant difference in body weight,hemoglobin,prealbumin,and albumin between the two groups at 1,3 and 6 months after surgery,the diet of patients in the DTR group was better than that in the RY group(P=0.031).CONCLUSION The clinical effect of DTR in TLTG is better than that of RY,indicating that it is a more valuable digestive tract reconstruction method in laparoscopic gastric cancer surgery.
基金supported by the National Natural Science Foundation of China(Grant Nos.61575205 and 62175022)Sichuan Natural Science Foundation(2022NSFSC0803)Sichuan Science and Technology Program(2021JDRC0035).
文摘The nonuniform distribution of interference spectrum in wavenumber k-space is a key issue to limit the imaging quality of Fourier-domain optical coherence tomography(FD-OCT).At present,the reconstruction quality at different depths among a variety of processing methods in k-space is still uncertain.Using simulated and experimental interference spectra at different depths,the effects of common six processing methods including uniform resampling(linear interpolation(LI),cubic spline interpolation(CSI),time-domain interpolation(TDI),and K-B window convolution)and nonuniform sampling direct-reconstruction(Lomb periodogram(LP)and nonuniform discrete Fourier transform(NDFT))on the reconstruction quality of FD-OCT were quantitatively analyzed and compared in this work.The results obtained by using simulated and experimental data were coincident.From the experimental results,the averaged peak intensity,axial resolution,and signal-to-noise ratio(SNR)of NDFT at depth from 0.5 to 3.0mm were improved by about 1.9 dB,1.4 times,and 11.8 dB,respectively,compared to the averaged indices of all the uniform resampling methods at all depths.Similarly,the improvements of the above three indices of LP were 2.0 dB,1.4 times,and 11.7 dB,respectively.The analysis method and the results obtained in this work are helpful to select an appropriate processing method in k-space,so as to improve the imaging quality of FD-OCT.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFA0501100)the National Natural Science Foundation of China(Grant Nos.91530321,31570742,and 31570727)Science and Technology Planning Project of Hunan Province,China(Grant No.2017RS3033)
文摘Three-dimensional(3 D)reconstruction of icosahedral viruses has played a crucial role in the development of cryoelectron microscopy single-particle reconstruction,with many cryo-electron microscopy techniques first established for structural studies of icosahedral viruses,owing to their high symmetry and large mass.This review summarizes the computational methods for icosahedral and symmetry-mismatch reconstruction of viruses,as well as the likely challenges and bottlenecks in virus reconstruction,such as symmetry mismatch reconstruction,contrast transformation function(CTF)correction,and particle distortion.
基金G.I.Montecinos thanks the National Chilean Fund for Scientific and Technological Development,FONDECYT(Fondo Nacional de Desarrollo Científico y Tecnológico),in the frame of the project for Initiation in Research 11180926
文摘The ADER approach to solve hyperbolic equations to very high order of accuracy has seen explosive developments in the last few years,including both methodological aspects as well as very ambitious applications.In spite of methodological progress,the issues of efficiency and ease of implementation of the solution of the associated generalized Riemann problem(GRP)remain the centre of attention in the ADER approach.In the original formulation of ADER schemes,the proposed solution procedure for the GRP was based on(i)Taylor series expansion of the solution in time right at the element interface,(ii)subsequent application of the Cauchy-Kowalewskaya procedure to convert time derivatives to functionals of space derivatives,and(iii)solution of classical Riemann problems for high-order spatial derivatives to complete the Taylor series expansion.For realistic problems the Cauchy-Kowalewskaya procedure requires the use of symbolic manipulators and being rather cumbersome its replacement or simplification is highly desirable.In this paper we propose a new class of solvers for the GRP that avoid the Cauchy-Kowalewskaya procedure and result in simpler ADER schemes.This is achieved by exploiting the history of the numerical solution that makes it possible to devise a time-reconstruction procedure at the element interface.Still relying on a time Taylor series expansion of the solution at the interface,the time derivatives are then easily calculated from the time-reconstruction polynomial.The resulting schemes are called ADER-TR.A thorough study of the linear stability properties of the linear version of the schemes is carried out using the von Neumann method,thus deducing linear stability regions.Also,via careful numerical experiments,we deduce stability regions for the corresponding non-linear schemes.Numerical examples using the present simplified schemes of fifth and seventh order of accuracy in space and time show that these compare favourably with conventional ADER methods.This paper is restricted to the one-dimensional scalar case with source term,but preliminary results for the one-dimensional Euler equations indicate that the time-reconstruction approach offers significant advantages not only in terms of ease of implementation but also in terms of efficiency for the high-order range schemes.
基金National Natural Science Foundation of China, No.41271416 CAS ＂Strategic Priority Research Program＂, No.XDA05090310
文摘Understanding long-term human-environment interactions requires historical reconstruction of past land-use and land-cover changes. Most reconstructions have been based primarily on consistently available and relatively standardized information from historical sources. Based on available data sources and a retrospective research, in this paper we review the approaches and methods of the digital reconstruction and analyze their advantages and possible constraints in the following aspects： （1） Historical documents contain qualitative or semi-quantitative information about past land use, which also usually include land-cover data, but preparation of archival documents is very time-consuming. （2） Historical maps and pictures offer visual and spatial quantitative land-cover information. （3） Natural archive has significant advantages as a method for reconstructing past vegetation and has its unique possibilities especially when historical records are missing or lacking, but it has great limits of rebuilding certain land-cover types. （4） Historical reconstruction models have been gradually developed from empirical models to mechanistic ones. The method does not only reconstruct the quantity of land use/cover in historical periods, but it also reproduces the spatial distribution. Yet there are still few historical land-cover datasets with high spatial resolution. （5） Reconstruction method based on multiple-source data and multidisciplinary research could build historical land-cover from multiple perspectives, complement the missing data, verify reconstruction results and thus improve reconstruction accuracy. However, there are challenges that make the method still in the exploratory stage. This method can be a long-term development goal for the historical land-cover reconstruction. Researchers should focus on rebuilding historical land-cover dataset with high spatial resolution by developing new models so that the study results could be effectively applied in simulations of climatic and ecological effects.
基金supported by the National High Technology Research and Development Program of China(863 Program)(Grant No.2014AA01A705)National Science and Technology Major Project of China(Grant No.2015ZX03001034)
文摘In this paper, we study the low-complexity channel reconstruction methods for downlink precoding in massive multiple-Input multiple-Output(MIMO) systems. When the user is allocated less streams than the number of its antennas, the base station(BS) or user usually utilizes the singular value decomposition(SVD) to get the effective channels, whose dimension is equal to the number of streams. This process is called channel reconstruction and done in BS for time division duplex(TDD) mode. However, with the increasing of antennas in BS, the computation burden of SVD is getting incredible. Here, we propose a series of novel low-complexity channel reconstruction methods for downlink precoding in 3D spatial channel model. We consider different correlations between elevation and azimuth antennas, and divide the large dimensional matrix SVD into two kinds of small-size matrix SVD. The simulation results show that the proposed methods only produce less than 10% float computation than the traditional SVD zero-forcing(SVD-ZF) precoding method, while keeping nearly the same performance of 1Gbps.
文摘A simple,efficient and accurate high resolution method to tracking moving-interfaces-the characteristic integral-averaging finite volume method on unstructured meshes is proposed. And some numerical tests and evaluation of six main efficient methods for interface reconstruction are made. Through strict numerical simulation,their characters,advantages and shortcomings are compared,analyzed and commended in particular.
基金Supported by the National Natural Science Foundation of China(U1462206)
文摘Molecular management is a promising technology to face challenges in the refining industry, such as more stringent requirements for product oil and heavier crude oil, and to maximize the value of every molecule in petroleum fractions. To achieve molecular management in refining processes, a novel model that is based on structure oriented lumping(SOL) and group contribution(GC) methods was proposed in this study. SOL method was applied to describe a petroleum fraction with structural increments, and GC method aimed to estimate molecular properties. The latter was achieved by associating rules between SOL structural increments and GC structures. A three-step reconstruction algorithm was developed to build a representative set of molecules from partial analytical data. First, structural distribution parameters were optimized with several properties. Then, a molecular library was created by using the optimized parameters. In the final step, maximum information entropy(MIE) method was applied to obtain a molecular fraction. Two industrial samples were used to validate the method, and the simulation results of the feedstock properties agreed well with the experimental data.
基金supported by the National Natural Science Foundation of China under Grant No.61501064Sichuan Provincial Science and Technology Project under Grant No.2016GZ0122
文摘In the process of encoding and decoding,erasure codes over binary fields,which just need AND operations and XOR operations and therefore have a high computational efficiency,are widely used in various fields of information technology.A matrix decoding method is proposed in this paper.The method is a universal data reconstruction scheme for erasure codes over binary fields.Besides a pre-judgment that whether errors can be recovered,the method can rebuild sectors of loss data on a fault-tolerant storage system constructed by erasure codes for disk errors.Data reconstruction process of the new method has simple and clear steps,so it is beneficial for implementation of computer codes.And more,it can be applied to other non-binary fields easily,so it is expected that the method has an extensive application in the future.
文摘Three-dimensional(3D)reconstruction of human organs has gained attention in recent years due to advances in the Internet and graphics processing units.In the coming years,most patient care will shift toward this new paradigm.However,development of fast and accurate 3D models from medical images or a set of medical scans remains a daunting task due to the number of pre-processing steps involved,most of which are dependent on human expertise.In this review,a survey of pre-processing steps was conducted,and reconstruction techniques for several organs in medical diagnosis were studied.Various methods and principles related to 3D reconstruction were highlighted.The usefulness of 3D reconstruction of organs in medical diagnosis was also highlighted.
文摘In ophthalmological practice,eyelid reconstruction is often needed because of the presence of defects that arise after the excision of a tumor or after injuries.Various methods for reconstructing these defects have been previously described.However,it is important to understand the basic principles underlying these techniques and their advantages and disadvantages to ensure the choice of the optimal technique in a particular case.We have analyzed the recent literature on new methods or modifications of existing ones to provide a brief overview of the reconstructive methods of the century for comparison.We searched PubMed and CyberLeninka for articles on restoring eyelid defects reported in the literature over the past 10 years.Most techniques can be considered modified classical reconstruction methods.Postoperative complications included aesthetic defects,such as scarring of the upper or lower eyelid,trichiasis,entropion,and lagophthalmos.Surgeons continue to search for the best methods for complex reconstructive surgery to achieve good cosmetic and aesthetic outcomes.
基金Project supported by the National Key Project, China (Grant No. GJXM92579).
文摘The accuracy of unstructured finite volume methods is greatly influenced by the gradient reconstruction, for which the stencil selection plays a critical role. Compared with the commonly used face-neighbor and vertex-neighbor stencils, the global-direction stencil is independent of the mesh topology, and characteristics of the flow field can be well reflected by this novel stencil. However, for a high-aspect-ratio triangular grid, the grid skewness is evident, which is one of the most important grid-quality measures known to affect the accuracy and stability of finite volume solvers. On this basis and inspired by an approach of using face-area-weighted centroid to reduce the grid skewness, we explore a method by combining the global-direction stencil and face-area-weighted centroid on high-aspect-ratio triangular grids, so as to improve the computational accuracy. Four representative numerical cases are simulated on high-aspect-ratio triangular grids to examine the validity of the improved global-direction stencil. Results illustrate that errors of this improved methods are the lowest among all methods we tested, and in high-mach-number flow, with the increase of cell aspect ratio, the improved global-direction stencil always has a better stability than commonly used face-neighbor and vertex-neighbor stencils. Therefore, the computational accuracy as well as stability is greatly improved, and superiorities of this novel method are verified.
文摘Data collected in two-dimensional projections give planar images of object at each projection angle. To obtain information along the depth of the object, tomographic images are reconstructed using these projections. There are basically two approaches to solve the problem of reconstruction: analytical and iterative, each one presenting its own advantages and limitations. This paper provides a detailed introduction and comparison to four analytical image reconstruction methods including Fourier transformation, simple back-projection, back-projection filtering and filtered back-projection.
基金National NaturalScinece Foundation of China.Grant number:30 0 70 336.U niversity FoundationofHUST.Grant number:0 10 1170 0 5 4
文摘MRSI plays a more and more important role in clinical application. In this paper,we compare several fast MRSI technologies and data reconstruction methods. For the conventional phase encoding MRSI,the data reconstruction using FFT is simple. But the data acquisition is very time consuming and thus prohibitive in clinical settings. Up to now,the MRSI technologies based on echo-planar, spiral trajectories and sensitivity encoding are the fastest in data acquisition,but their data reconstruction is complex. EPSI reconstruction uses shift of odd and even echoes. Spiral SI uses gridding FFT. SENSE-SI,a new approach to reducing the acquisition time,uses the distinct spatial sensitivities of the individual coil elements to recover the missing encoding information. These improvements in data acquisition and image reconstruction provide a potential value of metabolic imaging as a clinical tool.
文摘Objective To measure the tensile strength of the normal medial patellofemoral ligament(MPFL),and evaluate the biomechanics of different fixation methods of the hamstring tendon graft on the patella.Methods Eight fresh cadaver knees were prepared by isolating the patella,leaving only the MPFL as its attachment to the medial condyle of femur.The MPFL was reconstructed by three different methods:four-suture fixation,anchors-single suture fixation,and anchors-double suture fixation.The tensile strength and the elongation of the normal MPFL and the tendon grafts were measured.Results The tensile strength of the four-suture fixation group(234.86±49.02 N)was stronger than that of the normal MPFL(146.91±25.30 N,P=0.0014)and the anchors-single suture group(159.17±49.07N,P=0.0077),while weaker than that of the anchors-double suture group(314.74±78.46 N,P=0.0052)Conclusions With regard to the tensile strength,the four-suture fixation method is reliable for clinical use.Compared with the anchor-suture method,the four-suture fixation method which has no specific implants is more economical,convenient and efficient.
文摘In this paper, the problem of reconstructing numerical derivatives from noisy data is considered. A new framework of mollification methods based on the L generalized solution regularization methods is proposed. A specific algorithm for the first three derivatives is presented in the paper, in which a modification of TSVD, termed cTSVD is chosen as the regularization technique. Numerical examples given in the paper verify the theoretical results and show efficiency of the new method.
文摘Total and even partial glossectomy could be a major event in the life of a patient. Tongue function is so complicated which makes maintaining normal functions of the tongue such as swallowing and speech and preserving larynx integrity after the surgery is a primary objective of the surgeon. This task is very difficult and the result is not predictable. Recent years, however, there has been interesting developments in microsurgical techniques, and these advancements enable oral and maxillofacial surgeons to achieve better results and improve the quality of their patient′s life. The results even with use of the new technology are still far from perfect. Several reasons may cause variation in the result. Some of them have to do with the patient such as general health and other reasons are due to the method that is used and nature of the defect after the removal of the tumor. This article was undertaken to summarize the various methods and techniques used over the years to restore oral tongue functions after defects.
基金supported by the National Key Research and Development Program of China,No.2023YFC3603705(to DX)the National Natural Science Foundation of China,No.82302866(to YZ).
文摘After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the timing of interventions,combined with the limitations of current methods.To address these challenges,various techniques have been developed to aid in the repair and reconstruction of neural circuits at different stages of injury.Notably,neuromodulation has garnered considerable attention for its potential to enhance nerve regeneration,provide neuroprotection,restore neurons,and regulate the neural reorganization of circuits within the cerebral cortex and corticospinal tract.To improve the effectiveness of these interventions,the implementation of multitarget early interventional neuromodulation strategies,such as electrical and magnetic stimulation,is recommended to enhance functional recovery across different phases of nerve injury.This review concisely outlines the challenges encountered following spinal cord injury,synthesizes existing neurostimulation techniques while emphasizing neuroprotection,repair,and regeneration of impaired connections,and advocates for multi-targeted,task-oriented,and timely interventions.
