Conservative chaotic systems have unique advantages over dissipative chaotic systems in the fields of secure communication and pseudo-random number generator because they do not have attractors but possess good traver...Conservative chaotic systems have unique advantages over dissipative chaotic systems in the fields of secure communication and pseudo-random number generator because they do not have attractors but possess good traversal and pseudorandomness. In this work, a novel five-dimensional(5D) Hamiltonian conservative hyperchaotic system is proposed based on the 5D Euler equation. The proposed system can have different types of coordinate transformations and time reversal symmetries. In this work, Hamilton energy and Casimir energy are analyzed firstly, and it is proved that the new system satisfies Hamilton energy conservation and can generate chaos. Then, the complex dynamic characteristics of the system are demonstrated and the conservatism and chaos characteristics of the system are verified through the correlation analysis methods such as phase diagram, equilibrium point, Lyapunov exponent, bifurcation diagram, and SE complexity. In addition, a detailed analysis of the multistable characteristics of the system reveals that many energy-related coexisting orbits exist. Based on the infinite number of center-type and saddle-type equilibrium points, the dynamic characteristics of the hidden multistability of the system are revealed. Then, the National Institute of Standards and Technology(NIST)test of the new system shows that the chaotic sequence generated by the system has strong pseudo-random. Finally, the circuit simulation and hardware circuit experiment of the system are carried out with Multisim simulation software and digital signal processor(DSP) respectively. The experimental results confirm that the new system has good ergodicity and realizability.展开更多
In this paper,we propose a novel Local Macroscopic Conservative(LoMaC)low rank tensor method with discontinuous Galerkin(DG)discretization for the physical and phase spaces for simulating the Vlasov-Poisson(VP)system....In this paper,we propose a novel Local Macroscopic Conservative(LoMaC)low rank tensor method with discontinuous Galerkin(DG)discretization for the physical and phase spaces for simulating the Vlasov-Poisson(VP)system.The LoMaC property refers to the exact local conservation of macroscopic mass,momentum,and energy at the discrete level.The recently developed LoMaC low rank tensor algorithm(arXiv:2207.00518)simultaneously evolves the macroscopic conservation laws of mass,momentum,and energy using the kinetic flux vector splitting;then the LoMaC property is realized by projecting the low rank kinetic solution onto a subspace that shares the same macroscopic observables.This paper is a generalization of our previous work,but with DG discretization to take advantage of its compactness and flexibility in handling boundary conditions and its superior accuracy in the long term.The algorithm is developed in a similar fashion as that for a finite difference scheme,by observing that the DG method can be viewed equivalently in a nodal fashion.With the nodal DG method,assuming a tensorized computational grid,one will be able to(i)derive differentiation matrices for different nodal points based on a DG upwind discretization of transport terms,and(ii)define a weighted inner product space based on the nodal DG grid points.The algorithm can be extended to the high dimensional problems by hierarchical Tucker(HT)decomposition of solution tensors and a corresponding conservative projection algorithm.In a similar spirit,the algorithm can be extended to DG methods on nodal points of an unstructured mesh,or to other types of discretization,e.g.,the spectral method in velocity direction.Extensive numerical results are performed to showcase the efficacy of the method.展开更多
BACKGROUND Acute appendicitis is one of the most common emergency abdominal disease,and recent studies have evaluated conservative treatment using antibiotics for uncomplicated appendicitis.Although the efficacy of co...BACKGROUND Acute appendicitis is one of the most common emergency abdominal disease,and recent studies have evaluated conservative treatment using antibiotics for uncomplicated appendicitis.Although the efficacy of conservative treatment for uncomplicated appendicitis is known,its efficacy for complicated appendicitis remains unknown,so are risk factors for the conservative treatment of appendi-citis.In our institution,conservative treatment has long been the first choice for most appendicitis cases,except for perforation.Therefore,this novel study inves-tigated the outcomes of conservative treatment for uncomplicated and compli-cated acute appendicitis and the risk factors associated with conservative treat-ment.treatment.The significant and independent predictors of resistance to conservative treatment were body temperature≥37.3℃,appendicolith and Douglas sinus fluid visible on computed tomography(CT).The rate of resistance to conservative treatment was 66.7%(6/9)for patients with the above three factors,22.9%(8/35)for patients with two factors(appendicolith and body temperature≥37.3℃),16.7%(2/12)for patients with two factors(Douglas sinus fluid and appendicolith)and 11.1%(1/9)for patients with two factors(Douglas sinus fluid and body temperature≥37.3℃).CONCLUSION A temperature≥37.3℃,appendicolith and Douglas sinus fluid on CT might be clinical risk factors of resistance to conservative treatment for acute appendicitis.展开更多
Secondary hyperparathyroidism (HPT) is frequent in dialysis patients. Parathyroidectomy (PTX) is indicated for patients who failed medical therapy. We reviewed the data from 184 dialysis patients who underwent PTX bet...Secondary hyperparathyroidism (HPT) is frequent in dialysis patients. Parathyroidectomy (PTX) is indicated for patients who failed medical therapy. We reviewed the data from 184 dialysis patients who underwent PTX between January 2015 and January 2023. We aimed to evaluate the short and long term outcomes of PTX in dialysis patients, comparing the conservative 3/4 versus 7/8 techniques in this population.166 dialysis patients with secondary HPT were included. A conservative subtotal PTX (sPTX) 7/8 was performed in 72% of patients and sPTX 3/4 in 28% of them. Severe postoperative hypocalcaemiaocurred in 45 patients (27%). Hypocalcaemia was significantly more frequent in the sPTX 7/8 group (p = 0.012). One case of persistent HPT (0.6%) and 20 cases of recurrence (12%) were diagnosed. Recurrence was more frequent in the sPTX 3/4 group (15%). No deaths were reported during the perioperative period.展开更多
Congenital eversion of the upper eyelids is a rare condition, the exact cause of which remains unknown. It is more frequently associated with Down’s syndrome and black babies. If diagnosed early and treated properly,...Congenital eversion of the upper eyelids is a rare condition, the exact cause of which remains unknown. It is more frequently associated with Down’s syndrome and black babies. If diagnosed early and treated properly, the condition can be managed without surgery. We report a case of non syndromic congenital bilateral severe upper eyelid eversion in otherwise normal 3 days old neonate of African descent (Tanzanian), born by vaginal delivery. The case was conservatively managed by lubricants, antibiotics and eyelid patching. We report this case because from the best of our knowledge it has never been documented here at our hospital and Tanzania before.展开更多
Lumbar disc herniation(LDH)is a common orthopedic disease in clinical practice,with main symptoms of varying degrees of pain and functional impairment,seriously affecting the quality of work and life of patients,and a...Lumbar disc herniation(LDH)is a common orthopedic disease in clinical practice,with main symptoms of varying degrees of pain and functional impairment,seriously affecting the quality of work and life of patients,and also causing a certain degree of economic burden to the patient's family and society.At present,there are various conservative treatment methods for LDH in clinical practice.Conservative treatment has the characteristics of small trauma and high safety,which can achieve symptom relief and cure for most patients in clinical practice.This article aims to provide a scientific reference for the selection of treatment plans for LDH patients by reviewing relevant literature on conservative treatment of LDH that has been publicly reported both domestically and internationally in recent years.展开更多
In this paper Mei symmetry is introduced for a nonconservative system. The necessary and sufficient condition for a Mei symmetry to be also a Lie symmetry is derived. It is proved that the Mei symmetry leads to a non-...In this paper Mei symmetry is introduced for a nonconservative system. The necessary and sufficient condition for a Mei symmetry to be also a Lie symmetry is derived. It is proved that the Mei symmetry leads to a non-Noether conservative quantity via a Lie symmetry, and deduces a Lutzky conservative quantity via a Lie point symmetry.展开更多
In this paper,we develop an entropy-conservative discontinuous Galerkin(DG)method for the shallow water(SW)equation with random inputs.One of the most popular methods for uncertainty quantifcation is the generalized P...In this paper,we develop an entropy-conservative discontinuous Galerkin(DG)method for the shallow water(SW)equation with random inputs.One of the most popular methods for uncertainty quantifcation is the generalized Polynomial Chaos(gPC)approach which we consider in the following manuscript.We apply the stochastic Galerkin(SG)method to the stochastic SW equations.Using the SG approach in the stochastic hyperbolic SW system yields a purely deterministic system that is not necessarily hyperbolic anymore.The lack of the hyperbolicity leads to ill-posedness and stability issues in numerical simulations.By transforming the system using Roe variables,the hyperbolicity can be ensured and an entropy-entropy fux pair is known from a recent investigation by Gerster and Herty(Commun.Comput.Phys.27(3):639–671,2020).We use this pair and determine a corresponding entropy fux potential.Then,we construct entropy conservative numerical twopoint fuxes for this augmented system.By applying these new numerical fuxes in a nodal DG spectral element method(DGSEM)with fux diferencing ansatz,we obtain a provable entropy conservative(dissipative)scheme.In numerical experiments,we validate our theoretical fndings.展开更多
Aim To extend several fundamental theorems of conventional elasticity theory to quasicrystalelasticity theory. Methods The basic governing equations of quasicrystal elasticity theory and Gauss's theorem were appli...Aim To extend several fundamental theorems of conventional elasticity theory to quasicrystalelasticity theory. Methods The basic governing equations of quasicrystal elasticity theory and Gauss's theorem were applied in the derivation. Results and Conclusion The principle of virtual work, Betti's reciprocal theorem and the uniqueness theorem of quasicrystal elasticity theory are proud, and some conservative integrals in quasicrystal elasticty theory are obtained.展开更多
The conservative form and singular perturbed ordinary differential equation with periodic boundary value problem were studied, and a conservative difference scheme was constructed. Using the method of decomposing the ...The conservative form and singular perturbed ordinary differential equation with periodic boundary value problem were studied, and a conservative difference scheme was constructed. Using the method of decomposing the singular term from its solution and combining an asymptotic expansion of the equation, it is proved that the scheme converges uniformly to the solution of differential equation with order one.展开更多
For the conservative and non-conservative schemes of nonlinear evolution equations, by taking the two-dimensional shallow water wave equations as an example, a comparative analysis on computational stability is carrie...For the conservative and non-conservative schemes of nonlinear evolution equations, by taking the two-dimensional shallow water wave equations as an example, a comparative analysis on computational stability is carried out. The relationship between the nonlinear computational stability, the structure of the difference schemes, and the form of initial values is also discussed.展开更多
A new conservative finite difference scheme is presented based on the numerical analysis for an initialboundary value problem of a class of Schroedinger equation with the wave operator. The scheme can be linear and im...A new conservative finite difference scheme is presented based on the numerical analysis for an initialboundary value problem of a class of Schroedinger equation with the wave operator. The scheme can be linear and implicit or explicit based on the parameter choice. The initial value after discretization has second-order accuracy that is consistent with the scheme accuracy. The existence and the uniqueness of the difference solution are proved. Based on the priori estimates and an inequality about norms, the stability and the convergence of difference solutions with the second-order are proved in the energy norm. Experimental results demonstrate the efficiency of the new scheme.展开更多
Objective To investigate whether the very elderly patients with non-ST-segment elevation myocardial infarction (NSTEMI) will benefit from an invasive strategy versus a conservative strategy. Methods 190 consecutive pa...Objective To investigate whether the very elderly patients with non-ST-segment elevation myocardial infarction (NSTEMI) will benefit from an invasive strategy versus a conservative strategy. Methods 190 consecutive patients aged 80 years or older with NSTEMI were included in the retrospective study from September 2014 to August 2017, of which 69 patients received conservative strategy and 121 patients received invasive strategy. The primary outcome was death. Multivariate Cox regression models were used to assess the statistical association between strategies and mortality. The survival probability was further analyzed. Results The primary outcome occurred in 17.4% patients in the invasive group and in 42.0% patients in the conservative group (P = 0.0002). The readmission rate in the invasive group (14.9%) was higher than that in the conservative group (7.2%). Creatinine level (OR = 1.01, 95% CI: 0.10–1.03, P = 0.05) and use of diuretic (OR = 3.65, 95% CI: 1.56–8.53, P = 0.003) were independent influential factors for invasive strategy. HRs for multivariate Cox regression models were 3.45 (95% CI: 1.77–6.75, P = 0.0003), 3.02 (95% CI: 1.52–6.01, P = 0.0017), 2.93 (95% CI: 1. 46–5.86, P = 0.0024) and 2.47 (95% CI: 1.20–5.07, P = 0.0137). Compared with the patients received invasive strategy, the conservative group had remarkably reduced survival probability with time since treatment (P < 0.001). Conclusions An invasive strategy is superior to a conservative strategy in reducing mortality of patients aged 80 years or older with NSTEMI. Our results suggest that an invasive strategy is more suitable for the very elderly patients with NSTEMI in China.展开更多
BACKGROUND Arthroscopic debridement is a mature treatment for knee osteoarthritis(KOA).Due to the differences in the research subjects,methods,and efficacy evaluation indexes,there are great differences in the surgica...BACKGROUND Arthroscopic debridement is a mature treatment for knee osteoarthritis(KOA).Due to the differences in the research subjects,methods,and efficacy evaluation indexes,there are great differences in the surgical efficacy reported in the literature.AIM To compare the medium-term efficacy of arthroscopic debridement and conservative treatment for KOA of Kellgren-Lawrence grades I-III.METHODS Patients with KOA of Kellgren-Lawrence grades I-III who were admitted to the orthopedic clinic of our hospital from July 2018 to December 2018 and agreed to undergo arthroscopic surgery were included in an arthroscopic debridement group,and those who refused surgical treatment were included in a conservative treatment group.Gender,age,body mass index(BMI),side of KOA,American hospital for special surgery knee score(HSS score)before treatment,visual analogue scale(VAS)score during walking and rest before treatment,conservative treatment content,and surgical procedure were recorded.Outpatient visits were conducted at the 1st,3rd,6th,12th,and 24th mo after treatment in the two groups.The changes of HSS score and VAS score in each group before and after treatment were statistically analyzed,and the differences of HSS score and VAS score in different treatment stages between the two groups were also compared.RESULTS In the conservative treatment group,there were 80 patients with complete followup data,including 20 males and 60 females,aged 58.75±14.66 years old.And in the knee arthroscopic debridement group,there were 98 patients with complete follow-up data,including 24 males and 74 females,aged 59.27±14.48 years old.There was no statistically significant difference in the general data(gender,age,BMI,side of KOA,Kellgren-Lawrence grade distribution,HSS score,and VAS score)between the two groups before treatment.The HSS scores of the conservative treatment group at the 1st,3rd,6th,12th,and 24th mo after treatment were significantly higher than that before treatment(P<0.05).There was no statistical difference in HSS score of the conservative treatment group among the 1st,3rd,6th,12th,and 24th mo(P>0.05).The HSS score of the knee arthroscopic debridement group at the 1st mo after surgery was significantly higher than that before surgery(P<0.05).HSS scores of the knee arthroscopic debridement group at the 3rd,6th,12th,and 24th mo were significantly higher than those before surgery and at the 1st mo after surgery(P<0.05).There were no statistically significant differences in HSS scores at the 3rd,6th,12th,and 24th mo after surgery(P>0.05).HSS scores at the 3rd,6th,12th,and 24th mo were significantly higher in the arthroscopic debridement group than in the conservative treatment group(P<0.05).There was no statistical difference in HSS scores between the two groups before treatment and at the 1st mo of follow-up(P>0.05).VAS scores during walking and rest were significantly decreased in both groups,and the VAS score during rest was significantly lower in the arthroscopic debridement group than in the conservative treatment group,but there was no significant difference in the VAS score during walking between the two groups after treatment.CONCLUSION Compared with conservative treatment,arthroscopic debridement can significantly improve the knee resting pain and knee functional status of patients with KOA of Kellgren-Lawrence grades I-III within 2 years after treatment.展开更多
This study investigated possible effective treatments for cervical pregnancy, a rare form of ectopic pregnancy. The clinical records of 11 cases of ectopic pregnancy admitted to the Third Affiliated Hospital of Sun Ya...This study investigated possible effective treatments for cervical pregnancy, a rare form of ectopic pregnancy. The clinical records of 11 cases of ectopic pregnancy admitted to the Third Affiliated Hospital of Sun Yat-sen University from 1998 to 2010 were analyzed. All patients were treated with intermuscular injection of methotrexate （MTX, 50 mg）, and oral mifepristone （25 mg, bid）. All cases were successfully cured by conservative treatments using methotrexate plus mifepristone. Cervical pregnancy is a contributive factor to mutiple abortions and curettages. Methotrexate plus mifepristone, curettage through hysteroscopy and intracervical obturation with gauze are effective treatments of cervical pregnancy without the need for surgical intervention.展开更多
BACKGROUND Diverse presentations of dens invaginatus (DI) and root canal treatment with an immature open apex often pose challenges to dentists. Adequate treatment planning for DI is the main reason for successful app...BACKGROUND Diverse presentations of dens invaginatus (DI) and root canal treatment with an immature open apex often pose challenges to dentists. Adequate treatment planning for DI is the main reason for successful approach, i.e., we should consider the shape and depth of the concave folding, the condition of the original pulp, and the growth stage of the root formation. CASE SUMMARY A 9-year-old girl complained of severe pain of the right maxillary incisor (tooth 12) when chewing for two weeks. Following clinical and radiographic examinations, Oehlers type III DI of tooth 12, with an immature open apical foramen and a symptomatic periapical pathosis, was diagnosed. Cone-beam computed tomography verified the specific spatial and stereoscopic data regarding the communication between the main root canal and pseudo root canal of the involved tooth. After removing the source of infection, a mineral trioxide aggregate was selected to fill and seal the pseudo root canal;additionally, pulp capping of the main canal was performed through the interconnections between the root canals in the middle segment to preserve pulp vitality and enable continual root formation and eventual root apex closure. CONCLUSION We propose to conduct main root canal pulp capping for DI with communication between the main and pseudo root canals.展开更多
Knee osteoarthritis(KOA)is a common chronic debilitating disease with an estimated prevalence of 23.9%in the general adult population.The condition is characterised by joint pain,functional impairment and significant ...Knee osteoarthritis(KOA)is a common chronic debilitating disease with an estimated prevalence of 23.9%in the general adult population.The condition is characterised by joint pain,functional impairment and significant reduction in quality of life.Management for KOA can generally be divided into conservative(non-operative)and surgical(operative)measures.Conservative management broadly compromises pharmacological and non-pharmacological options and is conventionally the first line treatment to avoid or delay the need for surgical management.The aim of this study is to provide an overview of the current recommendations,efficacy and safety profile of different conservative treatments through a review of the literature.展开更多
BACKGROUND Widening of the pubic joint of more than 10 mm is diagnostic and defined as pubic symphysis diastasis and is considered a complication of vaginal childbirth or pregnancy.As it is a rare pathology(ranging fr...BACKGROUND Widening of the pubic joint of more than 10 mm is diagnostic and defined as pubic symphysis diastasis and is considered a complication of vaginal childbirth or pregnancy.As it is a rare pathology(ranging from 1 in 300 to 1 in 30000 pregnancies),no gold standard treatment has been defined.CASE SUMMARY This study examines two cases,a 27-year-old woman(gravida 1,para 1)and a 32-year-old woman(gravida 2,para 2),who presented to the clinic after uneventful vaginal deliveries.A normal pregnancy with no complications was observed in both patients.Severe pain in the pubic region occurred after labour and was accompanied by complicated locomotion.Pubic symphysis diastasis was confirmed radiologically and bed rest with lateral decubitus positioning was recommended.Oral non-steroidal antiinflammatory drugs were administered to relieve pain exacerbations.The symptoms decreased after treatment.Posttreatment magnetic resonance imaging(MRI)in the first case showed a reduction in symphyseal separation with no signs of osteitis.Three years later the symptoms recurred;MRI examination showed no further symphyseal widening or signs of osteitis.A relapse of symphyseal separation was diagnosed and conservative treatment was re-administered resulting in successful recovery.In the second case,pain recurred when the patient conceived for the second time.This time no benefit following conservative treatment was observed.Persistent pain and complicated locomotion led to scoliotic deformation of the lumbar part of the spine and leg length discrepancy,thus surgical treatment was chosen and internal pubic synthesis was performed.CONCLUSION Overall,surgical treatment resulting from insufficient conservative treatment showed a high risk of postoperative complications following the treatment of postpartum pubic symphysis diastasis.展开更多
The incidence of multifocal(MF) and multicentric(MC) carcinomas varies widely among clinical studies,depending on definitions and methods for pathological sampling.Magnetic resonance imaging is increasingly used becau...The incidence of multifocal(MF) and multicentric(MC) carcinomas varies widely among clinical studies,depending on definitions and methods for pathological sampling.Magnetic resonance imaging is increasingly used because it can help identify additional and conventionally occult tumors with high sensitivity.However,false positive lesions might incorrectly influence treatment decisions.Therefore,preoperative biopsies must be performed to avoid unnecessary surgery.Most studies have shown higher lymph node involvement rates in MF/MC tumors than in unifocal tumors.However,the rate of local recurrences is usually low after breast conservative treatment(BCT) of MC/MF tumors.It has been suggested that BCT is a reasonable option for MC/MF tumors in women aged 50-69 years,with small tumors and absence of extensive ductal carcinoma in situ.A metaanalysis showed an apparent decreased overall survival in MC/MF tumors but data are controversial.Surgery should achieve both acceptable cosmetic results and negative margins,which requires thorough preoperative radiological workup and localization of lesions.Boost radiotherapy techniques must be evaluated since double boosts might result in increased toxicity,namely fibrosis.In conclusion,BCT is feasible in selected patients with MC/MF but the choice of surgery must be discussed in a multidisciplinary team comprising at least radiologists,surgeons and radiotherapists.展开更多
For the holonomic nonconservative system, by using the Noether symmetry, a non-Noether conserved quantity is obtained directly under general infinitesimal transformations of groups in which time is variable. At first,...For the holonomic nonconservative system, by using the Noether symmetry, a non-Noether conserved quantity is obtained directly under general infinitesimal transformations of groups in which time is variable. At first,the Noether symmetry, Lie symmetry, and Noether conserved quantity are given. Secondly, the condition under which the Noether symmetry is a Lie symmetry under general infinitesimal transformations is obtained. Finally, a set of nonNoether conserved quantities of the system are given by the Noether symmetry, and an example is given to illustrate the application of the results.展开更多
基金Project supported by the Heilongjiang Province Natural Science Foundation Joint Guidance Project,China (Grant No.LH2020F022)the Fundamental Research Funds for the Central Universities,China (Grant No.3072022CF0801)。
文摘Conservative chaotic systems have unique advantages over dissipative chaotic systems in the fields of secure communication and pseudo-random number generator because they do not have attractors but possess good traversal and pseudorandomness. In this work, a novel five-dimensional(5D) Hamiltonian conservative hyperchaotic system is proposed based on the 5D Euler equation. The proposed system can have different types of coordinate transformations and time reversal symmetries. In this work, Hamilton energy and Casimir energy are analyzed firstly, and it is proved that the new system satisfies Hamilton energy conservation and can generate chaos. Then, the complex dynamic characteristics of the system are demonstrated and the conservatism and chaos characteristics of the system are verified through the correlation analysis methods such as phase diagram, equilibrium point, Lyapunov exponent, bifurcation diagram, and SE complexity. In addition, a detailed analysis of the multistable characteristics of the system reveals that many energy-related coexisting orbits exist. Based on the infinite number of center-type and saddle-type equilibrium points, the dynamic characteristics of the hidden multistability of the system are revealed. Then, the National Institute of Standards and Technology(NIST)test of the new system shows that the chaotic sequence generated by the system has strong pseudo-random. Finally, the circuit simulation and hardware circuit experiment of the system are carried out with Multisim simulation software and digital signal processor(DSP) respectively. The experimental results confirm that the new system has good ergodicity and realizability.
基金supported by the NSF(Grant Nos.the NSF-DMS-1818924 and 2111253)the Air Force Office of Scientific Research FA9550-22-1-0390 and Department of Energy DE-SC0023164+1 种基金supported by the NSF(Grant Nos.NSF-DMS-1830838 and NSF-DMS-2111383)the Air Force Office of Scientific Research FA9550-22-1-0390.
文摘In this paper,we propose a novel Local Macroscopic Conservative(LoMaC)low rank tensor method with discontinuous Galerkin(DG)discretization for the physical and phase spaces for simulating the Vlasov-Poisson(VP)system.The LoMaC property refers to the exact local conservation of macroscopic mass,momentum,and energy at the discrete level.The recently developed LoMaC low rank tensor algorithm(arXiv:2207.00518)simultaneously evolves the macroscopic conservation laws of mass,momentum,and energy using the kinetic flux vector splitting;then the LoMaC property is realized by projecting the low rank kinetic solution onto a subspace that shares the same macroscopic observables.This paper is a generalization of our previous work,but with DG discretization to take advantage of its compactness and flexibility in handling boundary conditions and its superior accuracy in the long term.The algorithm is developed in a similar fashion as that for a finite difference scheme,by observing that the DG method can be viewed equivalently in a nodal fashion.With the nodal DG method,assuming a tensorized computational grid,one will be able to(i)derive differentiation matrices for different nodal points based on a DG upwind discretization of transport terms,and(ii)define a weighted inner product space based on the nodal DG grid points.The algorithm can be extended to the high dimensional problems by hierarchical Tucker(HT)decomposition of solution tensors and a corresponding conservative projection algorithm.In a similar spirit,the algorithm can be extended to DG methods on nodal points of an unstructured mesh,or to other types of discretization,e.g.,the spectral method in velocity direction.Extensive numerical results are performed to showcase the efficacy of the method.
文摘BACKGROUND Acute appendicitis is one of the most common emergency abdominal disease,and recent studies have evaluated conservative treatment using antibiotics for uncomplicated appendicitis.Although the efficacy of conservative treatment for uncomplicated appendicitis is known,its efficacy for complicated appendicitis remains unknown,so are risk factors for the conservative treatment of appendi-citis.In our institution,conservative treatment has long been the first choice for most appendicitis cases,except for perforation.Therefore,this novel study inves-tigated the outcomes of conservative treatment for uncomplicated and compli-cated acute appendicitis and the risk factors associated with conservative treat-ment.treatment.The significant and independent predictors of resistance to conservative treatment were body temperature≥37.3℃,appendicolith and Douglas sinus fluid visible on computed tomography(CT).The rate of resistance to conservative treatment was 66.7%(6/9)for patients with the above three factors,22.9%(8/35)for patients with two factors(appendicolith and body temperature≥37.3℃),16.7%(2/12)for patients with two factors(Douglas sinus fluid and appendicolith)and 11.1%(1/9)for patients with two factors(Douglas sinus fluid and body temperature≥37.3℃).CONCLUSION A temperature≥37.3℃,appendicolith and Douglas sinus fluid on CT might be clinical risk factors of resistance to conservative treatment for acute appendicitis.
文摘Secondary hyperparathyroidism (HPT) is frequent in dialysis patients. Parathyroidectomy (PTX) is indicated for patients who failed medical therapy. We reviewed the data from 184 dialysis patients who underwent PTX between January 2015 and January 2023. We aimed to evaluate the short and long term outcomes of PTX in dialysis patients, comparing the conservative 3/4 versus 7/8 techniques in this population.166 dialysis patients with secondary HPT were included. A conservative subtotal PTX (sPTX) 7/8 was performed in 72% of patients and sPTX 3/4 in 28% of them. Severe postoperative hypocalcaemiaocurred in 45 patients (27%). Hypocalcaemia was significantly more frequent in the sPTX 7/8 group (p = 0.012). One case of persistent HPT (0.6%) and 20 cases of recurrence (12%) were diagnosed. Recurrence was more frequent in the sPTX 3/4 group (15%). No deaths were reported during the perioperative period.
文摘Congenital eversion of the upper eyelids is a rare condition, the exact cause of which remains unknown. It is more frequently associated with Down’s syndrome and black babies. If diagnosed early and treated properly, the condition can be managed without surgery. We report a case of non syndromic congenital bilateral severe upper eyelid eversion in otherwise normal 3 days old neonate of African descent (Tanzanian), born by vaginal delivery. The case was conservatively managed by lubricants, antibiotics and eyelid patching. We report this case because from the best of our knowledge it has never been documented here at our hospital and Tanzania before.
文摘Lumbar disc herniation(LDH)is a common orthopedic disease in clinical practice,with main symptoms of varying degrees of pain and functional impairment,seriously affecting the quality of work and life of patients,and also causing a certain degree of economic burden to the patient's family and society.At present,there are various conservative treatment methods for LDH in clinical practice.Conservative treatment has the characteristics of small trauma and high safety,which can achieve symptom relief and cure for most patients in clinical practice.This article aims to provide a scientific reference for the selection of treatment plans for LDH patients by reviewing relevant literature on conservative treatment of LDH that has been publicly reported both domestically and internationally in recent years.
基金Project supported by the State Key Laboratory of Scientific and Engineering Computing, Chinese Academy of Sciences and the National Natural Science Foundation of China （Grant Nos 10672143, 10471145 and 10372053） and the Natural Science Foundation of Henan Province Government of China（Grant Nos 0511022200 and 0311011400）.
文摘In this paper Mei symmetry is introduced for a nonconservative system. The necessary and sufficient condition for a Mei symmetry to be also a Lie symmetry is derived. It is proved that the Mei symmetry leads to a non-Noether conservative quantity via a Lie symmetry, and deduces a Lutzky conservative quantity via a Lie point symmetry.
文摘In this paper,we develop an entropy-conservative discontinuous Galerkin(DG)method for the shallow water(SW)equation with random inputs.One of the most popular methods for uncertainty quantifcation is the generalized Polynomial Chaos(gPC)approach which we consider in the following manuscript.We apply the stochastic Galerkin(SG)method to the stochastic SW equations.Using the SG approach in the stochastic hyperbolic SW system yields a purely deterministic system that is not necessarily hyperbolic anymore.The lack of the hyperbolicity leads to ill-posedness and stability issues in numerical simulations.By transforming the system using Roe variables,the hyperbolicity can be ensured and an entropy-entropy fux pair is known from a recent investigation by Gerster and Herty(Commun.Comput.Phys.27(3):639–671,2020).We use this pair and determine a corresponding entropy fux potential.Then,we construct entropy conservative numerical twopoint fuxes for this augmented system.By applying these new numerical fuxes in a nodal DG spectral element method(DGSEM)with fux diferencing ansatz,we obtain a provable entropy conservative(dissipative)scheme.In numerical experiments,we validate our theoretical fndings.
文摘Aim To extend several fundamental theorems of conventional elasticity theory to quasicrystalelasticity theory. Methods The basic governing equations of quasicrystal elasticity theory and Gauss's theorem were applied in the derivation. Results and Conclusion The principle of virtual work, Betti's reciprocal theorem and the uniqueness theorem of quasicrystal elasticity theory are proud, and some conservative integrals in quasicrystal elasticty theory are obtained.
文摘The conservative form and singular perturbed ordinary differential equation with periodic boundary value problem were studied, and a conservative difference scheme was constructed. Using the method of decomposing the singular term from its solution and combining an asymptotic expansion of the equation, it is proved that the scheme converges uniformly to the solution of differential equation with order one.
文摘For the conservative and non-conservative schemes of nonlinear evolution equations, by taking the two-dimensional shallow water wave equations as an example, a comparative analysis on computational stability is carried out. The relationship between the nonlinear computational stability, the structure of the difference schemes, and the form of initial values is also discussed.
文摘A new conservative finite difference scheme is presented based on the numerical analysis for an initialboundary value problem of a class of Schroedinger equation with the wave operator. The scheme can be linear and implicit or explicit based on the parameter choice. The initial value after discretization has second-order accuracy that is consistent with the scheme accuracy. The existence and the uniqueness of the difference solution are proved. Based on the priori estimates and an inequality about norms, the stability and the convergence of difference solutions with the second-order are proved in the energy norm. Experimental results demonstrate the efficiency of the new scheme.
文摘Objective To investigate whether the very elderly patients with non-ST-segment elevation myocardial infarction (NSTEMI) will benefit from an invasive strategy versus a conservative strategy. Methods 190 consecutive patients aged 80 years or older with NSTEMI were included in the retrospective study from September 2014 to August 2017, of which 69 patients received conservative strategy and 121 patients received invasive strategy. The primary outcome was death. Multivariate Cox regression models were used to assess the statistical association between strategies and mortality. The survival probability was further analyzed. Results The primary outcome occurred in 17.4% patients in the invasive group and in 42.0% patients in the conservative group (P = 0.0002). The readmission rate in the invasive group (14.9%) was higher than that in the conservative group (7.2%). Creatinine level (OR = 1.01, 95% CI: 0.10–1.03, P = 0.05) and use of diuretic (OR = 3.65, 95% CI: 1.56–8.53, P = 0.003) were independent influential factors for invasive strategy. HRs for multivariate Cox regression models were 3.45 (95% CI: 1.77–6.75, P = 0.0003), 3.02 (95% CI: 1.52–6.01, P = 0.0017), 2.93 (95% CI: 1. 46–5.86, P = 0.0024) and 2.47 (95% CI: 1.20–5.07, P = 0.0137). Compared with the patients received invasive strategy, the conservative group had remarkably reduced survival probability with time since treatment (P < 0.001). Conclusions An invasive strategy is superior to a conservative strategy in reducing mortality of patients aged 80 years or older with NSTEMI. Our results suggest that an invasive strategy is more suitable for the very elderly patients with NSTEMI in China.
基金Shanghai Jing'an District Health Research Project,China,No.2018MS09.
文摘BACKGROUND Arthroscopic debridement is a mature treatment for knee osteoarthritis(KOA).Due to the differences in the research subjects,methods,and efficacy evaluation indexes,there are great differences in the surgical efficacy reported in the literature.AIM To compare the medium-term efficacy of arthroscopic debridement and conservative treatment for KOA of Kellgren-Lawrence grades I-III.METHODS Patients with KOA of Kellgren-Lawrence grades I-III who were admitted to the orthopedic clinic of our hospital from July 2018 to December 2018 and agreed to undergo arthroscopic surgery were included in an arthroscopic debridement group,and those who refused surgical treatment were included in a conservative treatment group.Gender,age,body mass index(BMI),side of KOA,American hospital for special surgery knee score(HSS score)before treatment,visual analogue scale(VAS)score during walking and rest before treatment,conservative treatment content,and surgical procedure were recorded.Outpatient visits were conducted at the 1st,3rd,6th,12th,and 24th mo after treatment in the two groups.The changes of HSS score and VAS score in each group before and after treatment were statistically analyzed,and the differences of HSS score and VAS score in different treatment stages between the two groups were also compared.RESULTS In the conservative treatment group,there were 80 patients with complete followup data,including 20 males and 60 females,aged 58.75±14.66 years old.And in the knee arthroscopic debridement group,there were 98 patients with complete follow-up data,including 24 males and 74 females,aged 59.27±14.48 years old.There was no statistically significant difference in the general data(gender,age,BMI,side of KOA,Kellgren-Lawrence grade distribution,HSS score,and VAS score)between the two groups before treatment.The HSS scores of the conservative treatment group at the 1st,3rd,6th,12th,and 24th mo after treatment were significantly higher than that before treatment(P<0.05).There was no statistical difference in HSS score of the conservative treatment group among the 1st,3rd,6th,12th,and 24th mo(P>0.05).The HSS score of the knee arthroscopic debridement group at the 1st mo after surgery was significantly higher than that before surgery(P<0.05).HSS scores of the knee arthroscopic debridement group at the 3rd,6th,12th,and 24th mo were significantly higher than those before surgery and at the 1st mo after surgery(P<0.05).There were no statistically significant differences in HSS scores at the 3rd,6th,12th,and 24th mo after surgery(P>0.05).HSS scores at the 3rd,6th,12th,and 24th mo were significantly higher in the arthroscopic debridement group than in the conservative treatment group(P<0.05).There was no statistical difference in HSS scores between the two groups before treatment and at the 1st mo of follow-up(P>0.05).VAS scores during walking and rest were significantly decreased in both groups,and the VAS score during rest was significantly lower in the arthroscopic debridement group than in the conservative treatment group,but there was no significant difference in the VAS score during walking between the two groups after treatment.CONCLUSION Compared with conservative treatment,arthroscopic debridement can significantly improve the knee resting pain and knee functional status of patients with KOA of Kellgren-Lawrence grades I-III within 2 years after treatment.
文摘This study investigated possible effective treatments for cervical pregnancy, a rare form of ectopic pregnancy. The clinical records of 11 cases of ectopic pregnancy admitted to the Third Affiliated Hospital of Sun Yat-sen University from 1998 to 2010 were analyzed. All patients were treated with intermuscular injection of methotrexate （MTX, 50 mg）, and oral mifepristone （25 mg, bid）. All cases were successfully cured by conservative treatments using methotrexate plus mifepristone. Cervical pregnancy is a contributive factor to mutiple abortions and curettages. Methotrexate plus mifepristone, curettage through hysteroscopy and intracervical obturation with gauze are effective treatments of cervical pregnancy without the need for surgical intervention.
基金Supported by a grant from the Kaohsiung Medical University,No.KMUH106-6M52
文摘BACKGROUND Diverse presentations of dens invaginatus (DI) and root canal treatment with an immature open apex often pose challenges to dentists. Adequate treatment planning for DI is the main reason for successful approach, i.e., we should consider the shape and depth of the concave folding, the condition of the original pulp, and the growth stage of the root formation. CASE SUMMARY A 9-year-old girl complained of severe pain of the right maxillary incisor (tooth 12) when chewing for two weeks. Following clinical and radiographic examinations, Oehlers type III DI of tooth 12, with an immature open apical foramen and a symptomatic periapical pathosis, was diagnosed. Cone-beam computed tomography verified the specific spatial and stereoscopic data regarding the communication between the main root canal and pseudo root canal of the involved tooth. After removing the source of infection, a mineral trioxide aggregate was selected to fill and seal the pseudo root canal;additionally, pulp capping of the main canal was performed through the interconnections between the root canals in the middle segment to preserve pulp vitality and enable continual root formation and eventual root apex closure. CONCLUSION We propose to conduct main root canal pulp capping for DI with communication between the main and pseudo root canals.
文摘Knee osteoarthritis(KOA)is a common chronic debilitating disease with an estimated prevalence of 23.9%in the general adult population.The condition is characterised by joint pain,functional impairment and significant reduction in quality of life.Management for KOA can generally be divided into conservative(non-operative)and surgical(operative)measures.Conservative management broadly compromises pharmacological and non-pharmacological options and is conventionally the first line treatment to avoid or delay the need for surgical management.The aim of this study is to provide an overview of the current recommendations,efficacy and safety profile of different conservative treatments through a review of the literature.
文摘BACKGROUND Widening of the pubic joint of more than 10 mm is diagnostic and defined as pubic symphysis diastasis and is considered a complication of vaginal childbirth or pregnancy.As it is a rare pathology(ranging from 1 in 300 to 1 in 30000 pregnancies),no gold standard treatment has been defined.CASE SUMMARY This study examines two cases,a 27-year-old woman(gravida 1,para 1)and a 32-year-old woman(gravida 2,para 2),who presented to the clinic after uneventful vaginal deliveries.A normal pregnancy with no complications was observed in both patients.Severe pain in the pubic region occurred after labour and was accompanied by complicated locomotion.Pubic symphysis diastasis was confirmed radiologically and bed rest with lateral decubitus positioning was recommended.Oral non-steroidal antiinflammatory drugs were administered to relieve pain exacerbations.The symptoms decreased after treatment.Posttreatment magnetic resonance imaging(MRI)in the first case showed a reduction in symphyseal separation with no signs of osteitis.Three years later the symptoms recurred;MRI examination showed no further symphyseal widening or signs of osteitis.A relapse of symphyseal separation was diagnosed and conservative treatment was re-administered resulting in successful recovery.In the second case,pain recurred when the patient conceived for the second time.This time no benefit following conservative treatment was observed.Persistent pain and complicated locomotion led to scoliotic deformation of the lumbar part of the spine and leg length discrepancy,thus surgical treatment was chosen and internal pubic synthesis was performed.CONCLUSION Overall,surgical treatment resulting from insufficient conservative treatment showed a high risk of postoperative complications following the treatment of postpartum pubic symphysis diastasis.
文摘The incidence of multifocal(MF) and multicentric(MC) carcinomas varies widely among clinical studies,depending on definitions and methods for pathological sampling.Magnetic resonance imaging is increasingly used because it can help identify additional and conventionally occult tumors with high sensitivity.However,false positive lesions might incorrectly influence treatment decisions.Therefore,preoperative biopsies must be performed to avoid unnecessary surgery.Most studies have shown higher lymph node involvement rates in MF/MC tumors than in unifocal tumors.However,the rate of local recurrences is usually low after breast conservative treatment(BCT) of MC/MF tumors.It has been suggested that BCT is a reasonable option for MC/MF tumors in women aged 50-69 years,with small tumors and absence of extensive ductal carcinoma in situ.A metaanalysis showed an apparent decreased overall survival in MC/MF tumors but data are controversial.Surgery should achieve both acceptable cosmetic results and negative margins,which requires thorough preoperative radiological workup and localization of lesions.Boost radiotherapy techniques must be evaluated since double boosts might result in increased toxicity,namely fibrosis.In conclusion,BCT is feasible in selected patients with MC/MF but the choice of surgery must be discussed in a multidisciplinary team comprising at least radiologists,surgeons and radiotherapists.
基金国家自然科学基金，湖南省自然科学基金，the Scientific Research Foundation of Education Burean of Hunan Province
文摘For the holonomic nonconservative system, by using the Noether symmetry, a non-Noether conserved quantity is obtained directly under general infinitesimal transformations of groups in which time is variable. At first,the Noether symmetry, Lie symmetry, and Noether conserved quantity are given. Secondly, the condition under which the Noether symmetry is a Lie symmetry under general infinitesimal transformations is obtained. Finally, a set of nonNoether conserved quantities of the system are given by the Noether symmetry, and an example is given to illustrate the application of the results.
