Objective To explore the clinical effect of the trans-atlantoaxial pedicle screw-rod internal fixation and fusion in treatment of old odontoid fracture combined with atlantoaxial instability. Methods The study involve...Objective To explore the clinical effect of the trans-atlantoaxial pedicle screw-rod internal fixation and fusion in treatment of old odontoid fracture combined with atlantoaxial instability. Methods The study involved 48 patients with展开更多
Objective: The aim of this study is to evaluate clinical and radiological outcomes in subjects of atlantoaxial instability which were operated using C1 lateral mass and C2 pedicle screw (Harmes technique). Materials a...Objective: The aim of this study is to evaluate clinical and radiological outcomes in subjects of atlantoaxial instability which were operated using C1 lateral mass and C2 pedicle screw (Harmes technique). Materials and Methods: Twenty patients with atlantoaxial instability were scheduled at our clinic for atlantoaxial fusion using polyaxial C1 lateral mass and C2 pedicle screw between January 2008 and March 2014. Results: Trauma was the most common cause of atlantoaxial instability, seen in 18 (90%) patients. Modes of trauma were road traffic accident (75%) and falling (15%). Osteoarthritis was observed in 10% of cases. Patients were followed up with radiographs and clinical examinations. Satisfactory screw placement and reduction were achieved in all patients with the average union time of 3.5 months. There were no implant failures, nonunions, vertebral artery injuries or C2 nerve root injuries. Only, surgical site infections occur in 20% of cases that are improved with medical treatment. Conclusions: C1 lateral mass and C2 pedicle polyaxial screw fixation is an effective technique for the fusion of the atlantoaxial complex. It provides the highest fusion rates without any risk of vertebral injury.展开更多
The explicit analytical solution of Rosensweig instability spikes'shapes obtained by Navier-Stokes(NS)equation in diverse magnetic field H vertical to the flat free surface of ferrofluids are systematically studie...The explicit analytical solution of Rosensweig instability spikes'shapes obtained by Navier-Stokes(NS)equation in diverse magnetic field H vertical to the flat free surface of ferrofluids are systematically studied experimentally and theoretically.After carefully analyzing and solving the NS equation in elliptic form,the force balanced surface equations of spikes in Rosensweig instability are expressed as cosine wave in perturbated magnetic field and hyperbolic tangent in large magnetic field,whose results both reveal the wave-like nature of Rosensweig instability.The results of hyperbolic tangent form are perfectly fitted to the experimental results in this paper,which indicates that the analytical solution is basically correct.Using the forementioned theoretical results,the total energy of the spike distribution pattern is calculated.By analyzing the energy components under different magnetic field intensities H,the hexagon-square transition of Rosensweig instability is systematically discussed and explained in an explicit way.展开更多
By considering the joint effects of the Kelvin-Helmholtz(KH) and Rayleigh-Taylor(RT) instabilities, this paper presents an interpretation of the wavy patterns that occur in explosive welding. It is assumed that the el...By considering the joint effects of the Kelvin-Helmholtz(KH) and Rayleigh-Taylor(RT) instabilities, this paper presents an interpretation of the wavy patterns that occur in explosive welding. It is assumed that the elasticity of the material at the interface effectively determines the wavelength, because explosive welding is basically a solid-state welding process. To this end, an analytical model of elastic hydrodynamic instabilities is proposed, and the most unstable mode is selected in the solid phase. Similar approaches have been widely used to study the interfacial behavior of solid metals in high-energy-density physics. By comparing the experimental and theoretical results, it is concluded that thermal softening,which significantly reduces the shear modulus, is necessary and sufficient for successful welding. The thermal softening is verified by theoretical analysis of the increase in temperature due to the impacting and sliding of the flyer and base plates, and some experimental observations are qualitatively validated.In summary, the combined effect of the KH and RT instabilities in solids determines the wavy morphology, and our theoretical results are in good qualitative agreement with experimental and numerical observations.展开更多
Introduction: There has been a surge in the use of tendoscopic surgery for treating peroneal tendons instability. The novelty of this approach demanded a literature review of its indications, limitations, and clinical...Introduction: There has been a surge in the use of tendoscopic surgery for treating peroneal tendons instability. The novelty of this approach demanded a literature review of its indications, limitations, and clinical outcomes. Aim: a literature review of the clinical studies reporting on tendoscopic peroneal tendon stabilisation surgery along with its outcomes and complications. Methods: We carried out a comprehensive review of the literature up until September 2022 with an extensive search of the MEDLINE, Embase and Cochrane library databases. Results: Initial search resulted in 66 articles. Four duplicate articles were removed. Further 30 articles were excluded after title and abstract screening. Eight studies satisfied the inclusion criteria and were included in this review. Articles were analysed for outcomes and complications. Conclusion: The tendoscopic technique for peroneal tendon instability is an effective and safe surgical technique with very low failure rate. Levels of Evidence: Level IV.展开更多
The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas w...The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects.We analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions numerically.The results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency.Additionally,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment.The numerical results and accompanying images obtained from our simulations provide support for the above conclusions.展开更多
We study the nonlinear stage of modulation instability(MI)in the non-intergrable pure-quartic nonlinear Schrödinger equation where the fourth-order dispersion is modulated periodically.Using the three-mode trunca...We study the nonlinear stage of modulation instability(MI)in the non-intergrable pure-quartic nonlinear Schrödinger equation where the fourth-order dispersion is modulated periodically.Using the three-mode truncation,we reveal the complex recurrence of parametric resonance(PR)breathers,where each recurrence is associated with two oscillation periods(PR period and internal oscillation period).The nonlinear stage of parametric instability admits the maximum energy exchange between the spectrum sidebands and central mode occurring outside the MI gain band.展开更多
The existence of a significant electron drift instability(EDI) in the Hall thruster is considered as one of the possible causes of the abnormal increase in axial electron mobility near the outlet of the channel. In re...The existence of a significant electron drift instability(EDI) in the Hall thruster is considered as one of the possible causes of the abnormal increase in axial electron mobility near the outlet of the channel. In recent years, extensive simulation research on the characteristics of EDI has been conducted, but the excitation mechanism and growth mechanism of EDI in linear stage and nonlinear stage remain unclear. In this work, a one-dimensional PIC model in the azimuthal direction of the thruster near-exit region is established to gain further insights into the mechanism of the EDI in detail, and the effects of different types of propellants on EDI characteristics are discussed. The changes in axial electron transport caused by EDI under different types of propellants and electromagnetic field strengths are also examined. The results indicate that EDI undergoes a short linear growth phase before transitioning to the nonlinear phase and finally reaching saturation through the ion Landau damping. The EDI drives a significant ion heating in the azimuthal direction through electron–ion friction before entering the quasi-steady state, which increases the axial mobility of the electrons. Using lighter atomic weight propellant can effectively suppress the oscillation amplitude of EDI, but it will increase the linear growth rate, frequency, and phase velocity of EDI. Compared with the classical mobility, the axial electron mobility under the EDI increases by three orders of magnitude, which is consistent with experimental phenomena. The change of propellant type is insufficient to significantly change the axial electron mobility. It is also found that the collisions between electrons and neutral gasescan significantly affect the axial electron mobility under the influence of EDI, and lead the strength of the electric field to increase and the strength of the magnetic field to decrease, thereby both effectively suppressing the axial transport of electrons.展开更多
The coupling between wind stress perturbations and sea surface temperature(SST)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the ...The coupling between wind stress perturbations and sea surface temperature(SST)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the atmosphere and ocean.However,an overlooked fact by previous studies is that the loosely defined“TIWs”actually consist of two modes,including the Yanai wave-based TIW on the equator(hereafter eTIW)and the Rossby wave-based TIW off the equator(hereafter vTIW).Hence,the individual feedbacks of the wind stress to the bimodal TIWs remain unexplored.In this study,individual coupling relationships are established for both eTIW and v TIW,including the relationship between the TIW-induced SST perturbations and two components of wind stress perturbations,and the relationship between the TIW-induced wind stress perturbation divergence(curl)and the downwind(crosswind)TIW-induced SST gradients.Results show that,due to different distributions of eTIW and vTIW,the coupling strength induced by the eTIW is stronger on the equator,and that by the vTIW is stronger off the equator.The results of any of eTIW and vTIW are higher than those of the loosely defined TIWs.We further investigated how well the coupling relationships remained in several widely recognized oceanic general circulation models and fully coupled climate models.However,the coupling relationships cannot be well represented in most numerical models.Finally,we confirmed that higher resolution usually corresponds to more accurate simulation.Therefore,the coupling models established in this study are complementary to previous research and can be used to refine the oceanic and coupled climate models.展开更多
The homogeneity-breaking instability of the periodic solutions triggered by Hopf bifurcations of a diffusive Gierer-Meinhart system is studied in this paper.Sufficient conditions on the diffusion coefficients and the ...The homogeneity-breaking instability of the periodic solutions triggered by Hopf bifurcations of a diffusive Gierer-Meinhart system is studied in this paper.Sufficient conditions on the diffusion coefficients and the cross diffusion coefficients were derived to guarantee the occurrence of the aforementioned homogeneity-breaking instability.展开更多
BACKGROUND Long non-coding RNAs(LncRNAs)have been found to be a potential prognostic factor for cancers,including hepatocellular carcinoma(HCC).Some LncRNAs have been confirmed as potential indicators to quantify geno...BACKGROUND Long non-coding RNAs(LncRNAs)have been found to be a potential prognostic factor for cancers,including hepatocellular carcinoma(HCC).Some LncRNAs have been confirmed as potential indicators to quantify genomic instability(GI).Nevertheless,GI-LncRNAs remain largely unexplored.This study established a GI-derived LncRNA signature(GILncSig)that can predict the prognosis of HCC patients.AIM To establish a GILncSig that can predict the prognosis of HCC patients.METHODS Identification of GI-LncRNAs was conducted by combining LncRNA expression and somatic mutation profiles.The GI-LncRNAs were then analyzed for functional enrichment.The GILncSig was established in the training set by Cox regression analysis,and its predictive ability was verified in the testing set and TCGA set.In addition,we explored the effects of the GILncSig and TP53 on prognosis.RESULTS A total of 88 GI-LncRNAs were found,and functional enrichment analysis showed that their functions were mainly involved in small molecule metabolism and GI.The GILncSig was constructed by 5 LncRNAs(miR210HG,AC016735.1,AC116351.1,AC010643.1,LUCAT1).In the training set,the prognosis of high-risk patients was significantly worse than that of low-risk patients,and similar results were verified in the testing set and TCGA set.Multivariate Cox regression analysis and stratified analysis confirmed that the GILncSig could be used as an independent prognostic factor.Receiver operating characteristic curve analysis of the GILncSig showed that the area under the curve(0.773)was higher than the two LncRNA signatures published recently.Furthermore,the GILncSig may have a better predictive performance than TP53 mutation status alone.CONCLUSION We established a GILncSig that can predict the prognosis of HCC patients,which will help to guide prognostic evaluation and treatment decisions.展开更多
Background:Chronic ankle instability(CAI) is a common sequela following an acute lateral ankle sprain(LAS).To treat an acture LAS more effectively and efficiently,it is important to identify patients at substantial ri...Background:Chronic ankle instability(CAI) is a common sequela following an acute lateral ankle sprain(LAS).To treat an acture LAS more effectively and efficiently,it is important to identify patients at substantial risk for developing CAI.This study identifies magnetic resonance imaging(MRI) manifestations for predicting CAI development after a first episode of LAS and explores appropriate clinical indications for ordering MRI scans for these patients.Methods:All patients with a first-episode LAS who received plain radiograph and MRI scanning within the first 2 weeks after LAS from December 1,2017 to December 1,2019 were identified.Data were collected using the Cumberland Ankle Instability Tool at final follow-up.Demographic and other related clinical variables,including age,sex,body mass index,and treatment were also recorded.Univariable and multivariable analyses were performed successively to identify risk factors for CAI after first-episode LAS.Results:A total 131 out of 362 patients with a mean follow-up of 3.0± 0.6 years(mean ± SD;2.0—4.1 years) developed CAI after first-episode LAS.According to multivariable regression,development of CAI after first-episode LAS was associated with 5 prognostic factors:age(odds ratio(OR)=0.96,95% confidence interval(95%CI):0.93-1.00,p=0.032);body mass index(OR=1.09,95%CI:1.02-1.17,p=0.009);posterior talofibular ligament injury(OR=2.17,95%CI:1.05-4.48,p=0.035);large bone marrow lesion of the talus(OR=2.69,95%CI:1.30-5.58,p=0.008),and Grade 2 effusion of the tibiotalar joint(OR=2.61,95%CI:1.39-4.89,p=0.003).When patients had at least 1 positive clinical finding in the 10-m walk test,anterior drawer test,or inversion tilt test,they had a 90.2% sensitivity and 77.4% specificity in terms of detecting at least 1 prognostic factor by MRI.Conclusion:MRI scanning is valuable in predicting CAI after first-episode LAS for those patients with at least 1 positive clinical finding in the10-m walk test,anterior drawer test,and inversion tilt test.Further prospective and large-scale studies are necessary for validation.展开更多
Objective To evaluate the clinical application of atlantoaxial joint fusion using anterior transarticular screw fixation and bone grafting for atlantoaxial joint instability. Methods Twenty-three cases of atlantoaxial...Objective To evaluate the clinical application of atlantoaxial joint fusion using anterior transarticular screw fixation and bone grafting for atlantoaxial joint instability. Methods Twenty-three cases of atlantoaxial joint instability were展开更多
Oral cavity cancers are part of head and neck cancers. They have become frequent in the world in general and Senegal in particular. This study evaluates microsatellite instability tumors in oral cavity cancers in Sene...Oral cavity cancers are part of head and neck cancers. They have become frequent in the world in general and Senegal in particular. This study evaluates microsatellite instability tumors in oral cavity cancers in Senegal. Forty cancerous tissues, 20 healthy tissues, and 12 blood tissues were included in this study. These tissues were collected from each patient during the biopsy after obtaining consent. DNA extraction, Polymerase Chain Reaction (PCR) and sequencing were carried out to obtain sequences. Mutation surveyor, Bioedit and Dnasp software were used to perform our analyses. High instability was found in 57.5% of patients with cancer. Moreover, 90% of the patients had the same motif on healthy and cancerous tissue. Furthermore, 26.12%, 20.72%, and 11.71% polymorphic sites were found in cancerous, healthy and blood tissue respectively. Thus, a similarity between cancerous and healthy tissues seems to exist. This implies that instability of the Bat 26 microsatellite could occur early in the occurrence of oral cavity cancers.展开更多
Background and Objectives: Chronic low-dose exposure to dichlorvos occurs in communities in Africa where the substance is used indiscriminately for a variety of purposes. This experiment used an animal model to evalua...Background and Objectives: Chronic low-dose exposure to dichlorvos occurs in communities in Africa where the substance is used indiscriminately for a variety of purposes. This experiment used an animal model to evaluate genomic instability induced by this pattern of chronic exposure and its relationship with some measures of fertility in males. Methods: Seventy-five male Rattus norvegicus rats obtained for this experiment, were randomly allotted into five groups. Dichlorvos was given by oral gavage at doses of 0.28 mg/kg, 0.56 mg/kg and, 1.68 mg/kg, respectively, to three of the groups, on alternate days for 50 weeks. The remaining two groups received plain drinking water and cyclophosphamide as negative and positive controls, respectively. Samples were collected at 17, 34, and 50 weeks. Sperm count, sperm morphology and serum levels of follicle-stimulating hormone, luteinizing hormone, dihydrotestosterone, oestrogen and progesterone were determined. Furthermore, the frequency of micronucleated polychromatic erythrocytes was determined in bone marrow cells obtained from the femur. Results: The mean ranks of micronuclei frequency had an increasing trend. The frequency of micronucleated polychromatic erythrocytes (MnPCE) had a significant negative correlation with oestrogen (r<sub>s</sub> = -0.47, p = 0.00, n = 50), follicle-stimulating hormone (r<sub>s</sub> = -0.41, p = 0.00, n = 50) and progesterone (r<sub>s</sub> = -0.37, p = 0.01, n = 50) serum levels. A positive monotonic relationship also existed between micronuclei frequency and those of tubular necrosis, tubular vacuolation, and residual bodies. A positive significant moderate correlation was found between MnPCE and the proportion of immotile sperms (r<sub>s</sub> = 0.41, p = 0.00, n = 50). Conclusion: The nature of the correlations between micronuclei frequency and the proportion of immotile sperms, adverse histological changes and serum hormone levels found in this study suggest genomic instability as the possible mechanism for diminished fertility in males chronically exposed to dichlorvos.展开更多
BACKGROUND Hemodynamic instability and shock are associated with untoward outcomes in gastrointestinal bleeding.However,there are no studies in the existing literature on the proportion of patients who developed these...BACKGROUND Hemodynamic instability and shock are associated with untoward outcomes in gastrointestinal bleeding.However,there are no studies in the existing literature on the proportion of patients who developed these outcomes after gastrointestinal bleeding.AIM To determine the pooled event rates in the available literature and specify them based on the bleeding source.METHODS The protocol was registered on PROSPERO in advance(CRD42021283258).A systematic search was performed in three databases(PubMed,EMBASE,and CENTRAL)on 14^(th) October 2021.Pooled proportions with 95%CI were calculated with a random-effects model.A subgroup analysis was carried out based on the time of assessment(on admission or during hospital stay).Heterogeneity was assessed by Higgins and Thompson’s I^(2) statistics.The Joanna Briggs Institute Prevalence Critical Appraisal Tool was used for the risk of bias assessment.The Reference Citation Analysis(https://www.referencecitationanalysis.com/)tool was applied to obtain the latest highlight articles.RESULTS We identified 11589 records,of which 220 studies were eligible for data extraction.The overall proportion of shock and hemodynamic instability in general gastrointestinal bleeding patients was 0.25(95%CI:0.17-0.36,I^(2)=100%).In non-variceal bleeding,the proportion was 0.22(95%CI:0.14-0.31,I^(2)=100%),whereas it was 0.25(95%CI:0.19-0.32,I^(2)=100%)in variceal bleeding.The proportion of patients with colonic diverticular bleeding who developed shock or hemodynamic instability was 0.12(95%CI:0.06-0.22,I^(2)=90%).The risk of bias was low,and heterogeneity was high in all analyses.CONCLUSION One in five,one in four,and one in eight patients develops shock or hemodynamic instability on admission or during hospitalization in the case of non-variceal,variceal,and colonic diverticular bleeding,respectively.展开更多
To study the effect of interface behaviour on the mechanical properties and damage evolution of PBX under combined tension-shear loading, the present work establishes the numerical model of a PBX three-phase hybrid sy...To study the effect of interface behaviour on the mechanical properties and damage evolution of PBX under combined tension-shear loading, the present work establishes the numerical model of a PBX three-phase hybrid system, which introduces a nonlinear plastic damage cohesion model to study the mechanical response and damage process. The parameters in the model were fitted and calibrated.Taking the crack growth rate as the feature, the damage state in each stage was determined, and the damage instability criterion was given. The effects of interfacial tensile strength and shear strength on the damage process of PBX were studied. On this basis, serrated and hemispherical structures interface of PBX has been developed, which affects the damage process and instability during the loading process.The results indicate that damage state response of PBX experiences the process of stable load bearing,unstable propagation, and complete failure. At the critical moment of instability, the overall equivalent effective strain of material reaches 3024 με and instability loading displacement reaches 0.39 mm. The increase of interfacial tensile strength and shear strength significantly inhibits the damage of PBX. The effect of interfacial shear strength on critical instability of PBX is approximately 1.7 times that of the interfacial tensile strength. Further, interface opening along the normal direction is the main damage form at the interface. Serrated and hemispherical rough interfaces can significantly inhibit propagation of cracks, and the load bearing capacity is improved by 22% and 9.7%, respectively. Appropriate improvement of the roughness of the interface structure can effectively improve the mechanical properties. It is significantly important to have a better understanding of deformation, damage and failure mechanisms of PBX and to improve our predictive ability.展开更多
BACKGROUND Atlantoaxial rotatory subluxation(AARS)is an uncommon disease with a greater prevalence among children than adults,and it is mostly associated with trauma.Iatrogenic spinal injury accounts for a low percent...BACKGROUND Atlantoaxial rotatory subluxation(AARS)is an uncommon disease with a greater prevalence among children than adults,and it is mostly associated with trauma.Iatrogenic spinal injury accounts for a low percentage of injuries.However,in AARS,20%-40%of cases are associated with surgery,and 48%are caused by infection.Here,we describe our experience with a case of iatrogenic AARS after general anesthesia.CASE SUMMARY A 12-year-old girl presented with right-sided torticollis and cervical motion limit.The patient had undergone thyroidectomy 2 mo ago.Computed tomography revealed AARS with bilateral locked facets.Following the failure of repeated external reduction under general anesthesia,the patient underwent an open surgical reduction.The patient gained atlantoaxial alignment without any complications.Follow-up radiographs showed a normal appearance without instability.The cervical spine of children is more predisposed to injury due to anatomical and biomechanical differences.AARS secondary to infection and surgery is known as Grisel’s syndrome,which involves non-traumatic AARS.Several cases of AARS after surgery and other procedures with no evidence of inflammation have been reported.Our experience shows that surgery requiring hyperextension of the neck after general anesthesia should also be included as a risk factor.CONCLUSION Surgeons and anesthesiologists should be careful not to excessively extend the neck during pediatric surgery.Moreover,clinicians caring for pediatric patients with recent head and neck procedures must be aware of common AARS presentations.展开更多
We study modulational instability of a resonantly polariton condensate in a discrete lattice.Employing a discrete gain-saturation model,we derive the dispersion relation for the modulational instability by means of th...We study modulational instability of a resonantly polariton condensate in a discrete lattice.Employing a discrete gain-saturation model,we derive the dispersion relation for the modulational instability by means of the linear-stability analysis.Effects of the pumping strength,the nonlinearity,the strength of the detuning,and the coupling strength on the modulation instability are investigated.It is found that the interplay between these parameters will dramatically change the modulational instability condition.We believe that the predicted results in this work can be useful for future possible experiment of exciton-polariton condensate in lattices.展开更多
Plastic instability, called Portevin-Le-Chatelier(PLC) effect, manifests itself as an unstable plastic flow during tensile tests of structural materials. This phenomenon has a strong influence on diverse properties, l...Plastic instability, called Portevin-Le-Chatelier(PLC) effect, manifests itself as an unstable plastic flow during tensile tests of structural materials. This phenomenon has a strong influence on diverse properties, leading to unexpected vulnerabilities in the service environment.Among various magnesium-based alloys, PLC phenomenon is most prominently observed in the Mg-Mn-Nd alloy under elevated temperature and low strain rate conditions. An important aim of the study is to clarify and compare the significance of the RE and Ca addition, which are known to cause a formation of a largely weakened non-basal type texture, in the occurrence of plastic instability. Due to the PLC phenomenon, there is a risk of weakening texture and formability improvement by the addition of RE and Ca elements in Mg alloys. Based on the understanding of the role of Nd to the PLC phenomenon in Mg-Mn alloy identified in previous studies, the PLC characteristics according to alloying elements and deformation conditions were compared and analyzed. To identify the micromechanical mechanisms of the PLC phenomenon, varies in the microstructure and mechanical properties during deformation of Mg-Mn binary and Ca or Nd-containing Mg-Mn-based ternary alloys in various conditions were systemically analyzed. The addition of Ca did not show a marked PLC effect due to the formation of low number density Mn-Ca and Ca-Ca solute clusters and an unbalanced Mn:Ca ratio. In contrast, the addition of Nd leads to the formation of a higher number density of Nd-Nd and Mn-Nd solute clusters than that of Ca-Ca and Mn-Ca solute clusters of the Mg-Mn-Ca alloy, resulting in a stable solute-dislocation interaction atmosphere under specific ranges of deformation temperature and strain rate. The deformation in the regime of PLC phenomenon, results in a decrease in ductility and an increase in strength, despite deformation at elevated temperatures with maintaining the weakened texture.展开更多
文摘Objective To explore the clinical effect of the trans-atlantoaxial pedicle screw-rod internal fixation and fusion in treatment of old odontoid fracture combined with atlantoaxial instability. Methods The study involved 48 patients with
文摘Objective: The aim of this study is to evaluate clinical and radiological outcomes in subjects of atlantoaxial instability which were operated using C1 lateral mass and C2 pedicle screw (Harmes technique). Materials and Methods: Twenty patients with atlantoaxial instability were scheduled at our clinic for atlantoaxial fusion using polyaxial C1 lateral mass and C2 pedicle screw between January 2008 and March 2014. Results: Trauma was the most common cause of atlantoaxial instability, seen in 18 (90%) patients. Modes of trauma were road traffic accident (75%) and falling (15%). Osteoarthritis was observed in 10% of cases. Patients were followed up with radiographs and clinical examinations. Satisfactory screw placement and reduction were achieved in all patients with the average union time of 3.5 months. There were no implant failures, nonunions, vertebral artery injuries or C2 nerve root injuries. Only, surgical site infections occur in 20% of cases that are improved with medical treatment. Conclusions: C1 lateral mass and C2 pedicle polyaxial screw fixation is an effective technique for the fusion of the atlantoaxial complex. It provides the highest fusion rates without any risk of vertebral injury.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51735006,51927810,and U1837206)Beijing Municipal Natural Science Foundation(Grant No.3182013).
文摘The explicit analytical solution of Rosensweig instability spikes'shapes obtained by Navier-Stokes(NS)equation in diverse magnetic field H vertical to the flat free surface of ferrofluids are systematically studied experimentally and theoretically.After carefully analyzing and solving the NS equation in elliptic form,the force balanced surface equations of spikes in Rosensweig instability are expressed as cosine wave in perturbated magnetic field and hyperbolic tangent in large magnetic field,whose results both reveal the wave-like nature of Rosensweig instability.The results of hyperbolic tangent form are perfectly fitted to the experimental results in this paper,which indicates that the analytical solution is basically correct.Using the forementioned theoretical results,the total energy of the spike distribution pattern is calculated.By analyzing the energy components under different magnetic field intensities H,the hexagon-square transition of Rosensweig instability is systematically discussed and explained in an explicit way.
基金the National Natural Science Foundation of China(Grant Nos.12002037 and 12141201).
文摘By considering the joint effects of the Kelvin-Helmholtz(KH) and Rayleigh-Taylor(RT) instabilities, this paper presents an interpretation of the wavy patterns that occur in explosive welding. It is assumed that the elasticity of the material at the interface effectively determines the wavelength, because explosive welding is basically a solid-state welding process. To this end, an analytical model of elastic hydrodynamic instabilities is proposed, and the most unstable mode is selected in the solid phase. Similar approaches have been widely used to study the interfacial behavior of solid metals in high-energy-density physics. By comparing the experimental and theoretical results, it is concluded that thermal softening,which significantly reduces the shear modulus, is necessary and sufficient for successful welding. The thermal softening is verified by theoretical analysis of the increase in temperature due to the impacting and sliding of the flyer and base plates, and some experimental observations are qualitatively validated.In summary, the combined effect of the KH and RT instabilities in solids determines the wavy morphology, and our theoretical results are in good qualitative agreement with experimental and numerical observations.
文摘Introduction: There has been a surge in the use of tendoscopic surgery for treating peroneal tendons instability. The novelty of this approach demanded a literature review of its indications, limitations, and clinical outcomes. Aim: a literature review of the clinical studies reporting on tendoscopic peroneal tendon stabilisation surgery along with its outcomes and complications. Methods: We carried out a comprehensive review of the literature up until September 2022 with an extensive search of the MEDLINE, Embase and Cochrane library databases. Results: Initial search resulted in 66 articles. Four duplicate articles were removed. Further 30 articles were excluded after title and abstract screening. Eight studies satisfied the inclusion criteria and were included in this review. Articles were analysed for outcomes and complications. Conclusion: The tendoscopic technique for peroneal tendon instability is an effective and safe surgical technique with very low failure rate. Levels of Evidence: Level IV.
基金Project supported by the National Natural Science Foundation of China (Grant No.12065015)the Hongliu Firstlevel Discipline Construction Project of Lanzhou University of Technology。
文摘The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects.We analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions numerically.The results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency.Additionally,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment.The numerical results and accompanying images obtained from our simulations provide support for the above conclusions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12175178 and 12247103)the Natural Science Basic Research Program of Shaanxi Province,China(Grant No.2022KJXX-71)the Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant No.22JSY016).
文摘We study the nonlinear stage of modulation instability(MI)in the non-intergrable pure-quartic nonlinear Schrödinger equation where the fourth-order dispersion is modulated periodically.Using the three-mode truncation,we reveal the complex recurrence of parametric resonance(PR)breathers,where each recurrence is associated with two oscillation periods(PR period and internal oscillation period).The nonlinear stage of parametric instability admits the maximum energy exchange between the spectrum sidebands and central mode occurring outside the MI gain band.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11975062 and 11605021)the Fundamental Research Funds for the Central Universities (Grant No.3132023192)。
文摘The existence of a significant electron drift instability(EDI) in the Hall thruster is considered as one of the possible causes of the abnormal increase in axial electron mobility near the outlet of the channel. In recent years, extensive simulation research on the characteristics of EDI has been conducted, but the excitation mechanism and growth mechanism of EDI in linear stage and nonlinear stage remain unclear. In this work, a one-dimensional PIC model in the azimuthal direction of the thruster near-exit region is established to gain further insights into the mechanism of the EDI in detail, and the effects of different types of propellants on EDI characteristics are discussed. The changes in axial electron transport caused by EDI under different types of propellants and electromagnetic field strengths are also examined. The results indicate that EDI undergoes a short linear growth phase before transitioning to the nonlinear phase and finally reaching saturation through the ion Landau damping. The EDI drives a significant ion heating in the azimuthal direction through electron–ion friction before entering the quasi-steady state, which increases the axial mobility of the electrons. Using lighter atomic weight propellant can effectively suppress the oscillation amplitude of EDI, but it will increase the linear growth rate, frequency, and phase velocity of EDI. Compared with the classical mobility, the axial electron mobility under the EDI increases by three orders of magnitude, which is consistent with experimental phenomena. The change of propellant type is insufficient to significantly change the axial electron mobility. It is also found that the collisions between electrons and neutral gasescan significantly affect the axial electron mobility under the influence of EDI, and lead the strength of the electric field to increase and the strength of the magnetic field to decrease, thereby both effectively suppressing the axial transport of electrons.
基金Supported by the National Natural Science Foundation of China(No.41976012)the Key Research Program of Laoshan Laboratory(LSL)(No.LSKJ 202202502)the Strategic Priority Research Program of Chinese Academy of Sciences(CAS)(No.XDB 42000000)。
文摘The coupling between wind stress perturbations and sea surface temperature(SST)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the atmosphere and ocean.However,an overlooked fact by previous studies is that the loosely defined“TIWs”actually consist of two modes,including the Yanai wave-based TIW on the equator(hereafter eTIW)and the Rossby wave-based TIW off the equator(hereafter vTIW).Hence,the individual feedbacks of the wind stress to the bimodal TIWs remain unexplored.In this study,individual coupling relationships are established for both eTIW and v TIW,including the relationship between the TIW-induced SST perturbations and two components of wind stress perturbations,and the relationship between the TIW-induced wind stress perturbation divergence(curl)and the downwind(crosswind)TIW-induced SST gradients.Results show that,due to different distributions of eTIW and vTIW,the coupling strength induced by the eTIW is stronger on the equator,and that by the vTIW is stronger off the equator.The results of any of eTIW and vTIW are higher than those of the loosely defined TIWs.We further investigated how well the coupling relationships remained in several widely recognized oceanic general circulation models and fully coupled climate models.However,the coupling relationships cannot be well represented in most numerical models.Finally,we confirmed that higher resolution usually corresponds to more accurate simulation.Therefore,the coupling models established in this study are complementary to previous research and can be used to refine the oceanic and coupled climate models.
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.12061033,2020GG0130,2020MS04007,2020BS11,and NJZZ22286).
文摘The homogeneity-breaking instability of the periodic solutions triggered by Hopf bifurcations of a diffusive Gierer-Meinhart system is studied in this paper.Sufficient conditions on the diffusion coefficients and the cross diffusion coefficients were derived to guarantee the occurrence of the aforementioned homogeneity-breaking instability.
文摘BACKGROUND Long non-coding RNAs(LncRNAs)have been found to be a potential prognostic factor for cancers,including hepatocellular carcinoma(HCC).Some LncRNAs have been confirmed as potential indicators to quantify genomic instability(GI).Nevertheless,GI-LncRNAs remain largely unexplored.This study established a GI-derived LncRNA signature(GILncSig)that can predict the prognosis of HCC patients.AIM To establish a GILncSig that can predict the prognosis of HCC patients.METHODS Identification of GI-LncRNAs was conducted by combining LncRNA expression and somatic mutation profiles.The GI-LncRNAs were then analyzed for functional enrichment.The GILncSig was established in the training set by Cox regression analysis,and its predictive ability was verified in the testing set and TCGA set.In addition,we explored the effects of the GILncSig and TP53 on prognosis.RESULTS A total of 88 GI-LncRNAs were found,and functional enrichment analysis showed that their functions were mainly involved in small molecule metabolism and GI.The GILncSig was constructed by 5 LncRNAs(miR210HG,AC016735.1,AC116351.1,AC010643.1,LUCAT1).In the training set,the prognosis of high-risk patients was significantly worse than that of low-risk patients,and similar results were verified in the testing set and TCGA set.Multivariate Cox regression analysis and stratified analysis confirmed that the GILncSig could be used as an independent prognostic factor.Receiver operating characteristic curve analysis of the GILncSig showed that the area under the curve(0.773)was higher than the two LncRNA signatures published recently.Furthermore,the GILncSig may have a better predictive performance than TP53 mutation status alone.CONCLUSION We established a GILncSig that can predict the prognosis of HCC patients,which will help to guide prognostic evaluation and treatment decisions.
基金supported by the Biomedicine Supporting Program of Shanghai "Science and Technology Innovation Plan" (19441902400)the Ningxia Hui Autonomous Region Key R&D program (2020BCH01001)+1 种基金the Shanghai "Science and Technology Innovation Action Plan" Domestic Science and Technology Cooperation Project (20025800200)the Clinical Research Program of Shanghai Municipal Health Commission (201940367)。
文摘Background:Chronic ankle instability(CAI) is a common sequela following an acute lateral ankle sprain(LAS).To treat an acture LAS more effectively and efficiently,it is important to identify patients at substantial risk for developing CAI.This study identifies magnetic resonance imaging(MRI) manifestations for predicting CAI development after a first episode of LAS and explores appropriate clinical indications for ordering MRI scans for these patients.Methods:All patients with a first-episode LAS who received plain radiograph and MRI scanning within the first 2 weeks after LAS from December 1,2017 to December 1,2019 were identified.Data were collected using the Cumberland Ankle Instability Tool at final follow-up.Demographic and other related clinical variables,including age,sex,body mass index,and treatment were also recorded.Univariable and multivariable analyses were performed successively to identify risk factors for CAI after first-episode LAS.Results:A total 131 out of 362 patients with a mean follow-up of 3.0± 0.6 years(mean ± SD;2.0—4.1 years) developed CAI after first-episode LAS.According to multivariable regression,development of CAI after first-episode LAS was associated with 5 prognostic factors:age(odds ratio(OR)=0.96,95% confidence interval(95%CI):0.93-1.00,p=0.032);body mass index(OR=1.09,95%CI:1.02-1.17,p=0.009);posterior talofibular ligament injury(OR=2.17,95%CI:1.05-4.48,p=0.035);large bone marrow lesion of the talus(OR=2.69,95%CI:1.30-5.58,p=0.008),and Grade 2 effusion of the tibiotalar joint(OR=2.61,95%CI:1.39-4.89,p=0.003).When patients had at least 1 positive clinical finding in the 10-m walk test,anterior drawer test,or inversion tilt test,they had a 90.2% sensitivity and 77.4% specificity in terms of detecting at least 1 prognostic factor by MRI.Conclusion:MRI scanning is valuable in predicting CAI after first-episode LAS for those patients with at least 1 positive clinical finding in the10-m walk test,anterior drawer test,and inversion tilt test.Further prospective and large-scale studies are necessary for validation.
文摘Objective To evaluate the clinical application of atlantoaxial joint fusion using anterior transarticular screw fixation and bone grafting for atlantoaxial joint instability. Methods Twenty-three cases of atlantoaxial joint instability were
文摘Oral cavity cancers are part of head and neck cancers. They have become frequent in the world in general and Senegal in particular. This study evaluates microsatellite instability tumors in oral cavity cancers in Senegal. Forty cancerous tissues, 20 healthy tissues, and 12 blood tissues were included in this study. These tissues were collected from each patient during the biopsy after obtaining consent. DNA extraction, Polymerase Chain Reaction (PCR) and sequencing were carried out to obtain sequences. Mutation surveyor, Bioedit and Dnasp software were used to perform our analyses. High instability was found in 57.5% of patients with cancer. Moreover, 90% of the patients had the same motif on healthy and cancerous tissue. Furthermore, 26.12%, 20.72%, and 11.71% polymorphic sites were found in cancerous, healthy and blood tissue respectively. Thus, a similarity between cancerous and healthy tissues seems to exist. This implies that instability of the Bat 26 microsatellite could occur early in the occurrence of oral cavity cancers.
文摘Background and Objectives: Chronic low-dose exposure to dichlorvos occurs in communities in Africa where the substance is used indiscriminately for a variety of purposes. This experiment used an animal model to evaluate genomic instability induced by this pattern of chronic exposure and its relationship with some measures of fertility in males. Methods: Seventy-five male Rattus norvegicus rats obtained for this experiment, were randomly allotted into five groups. Dichlorvos was given by oral gavage at doses of 0.28 mg/kg, 0.56 mg/kg and, 1.68 mg/kg, respectively, to three of the groups, on alternate days for 50 weeks. The remaining two groups received plain drinking water and cyclophosphamide as negative and positive controls, respectively. Samples were collected at 17, 34, and 50 weeks. Sperm count, sperm morphology and serum levels of follicle-stimulating hormone, luteinizing hormone, dihydrotestosterone, oestrogen and progesterone were determined. Furthermore, the frequency of micronucleated polychromatic erythrocytes was determined in bone marrow cells obtained from the femur. Results: The mean ranks of micronuclei frequency had an increasing trend. The frequency of micronucleated polychromatic erythrocytes (MnPCE) had a significant negative correlation with oestrogen (r<sub>s</sub> = -0.47, p = 0.00, n = 50), follicle-stimulating hormone (r<sub>s</sub> = -0.41, p = 0.00, n = 50) and progesterone (r<sub>s</sub> = -0.37, p = 0.01, n = 50) serum levels. A positive monotonic relationship also existed between micronuclei frequency and those of tubular necrosis, tubular vacuolation, and residual bodies. A positive significant moderate correlation was found between MnPCE and the proportion of immotile sperms (r<sub>s</sub> = 0.41, p = 0.00, n = 50). Conclusion: The nature of the correlations between micronuclei frequency and the proportion of immotile sperms, adverse histological changes and serum hormone levels found in this study suggest genomic instability as the possible mechanism for diminished fertility in males chronically exposed to dichlorvos.
基金The Ministry of Innovation and Technology of Hungary from the National Research,Development,and Innovation Fund(ITM-NRDIF),No.TKP2021-EGA-23.
文摘BACKGROUND Hemodynamic instability and shock are associated with untoward outcomes in gastrointestinal bleeding.However,there are no studies in the existing literature on the proportion of patients who developed these outcomes after gastrointestinal bleeding.AIM To determine the pooled event rates in the available literature and specify them based on the bleeding source.METHODS The protocol was registered on PROSPERO in advance(CRD42021283258).A systematic search was performed in three databases(PubMed,EMBASE,and CENTRAL)on 14^(th) October 2021.Pooled proportions with 95%CI were calculated with a random-effects model.A subgroup analysis was carried out based on the time of assessment(on admission or during hospital stay).Heterogeneity was assessed by Higgins and Thompson’s I^(2) statistics.The Joanna Briggs Institute Prevalence Critical Appraisal Tool was used for the risk of bias assessment.The Reference Citation Analysis(https://www.referencecitationanalysis.com/)tool was applied to obtain the latest highlight articles.RESULTS We identified 11589 records,of which 220 studies were eligible for data extraction.The overall proportion of shock and hemodynamic instability in general gastrointestinal bleeding patients was 0.25(95%CI:0.17-0.36,I^(2)=100%).In non-variceal bleeding,the proportion was 0.22(95%CI:0.14-0.31,I^(2)=100%),whereas it was 0.25(95%CI:0.19-0.32,I^(2)=100%)in variceal bleeding.The proportion of patients with colonic diverticular bleeding who developed shock or hemodynamic instability was 0.12(95%CI:0.06-0.22,I^(2)=90%).The risk of bias was low,and heterogeneity was high in all analyses.CONCLUSION One in five,one in four,and one in eight patients develops shock or hemodynamic instability on admission or during hospitalization in the case of non-variceal,variceal,and colonic diverticular bleeding,respectively.
基金the China National Nature Science Foundation (Grant No. 11872119)China Postdoctoral Science Foundation (Grant Nos. BX20200046, 2020M680394)Pre-research Project of Armament (Grant No. 6142A03202002) for supporting this project
文摘To study the effect of interface behaviour on the mechanical properties and damage evolution of PBX under combined tension-shear loading, the present work establishes the numerical model of a PBX three-phase hybrid system, which introduces a nonlinear plastic damage cohesion model to study the mechanical response and damage process. The parameters in the model were fitted and calibrated.Taking the crack growth rate as the feature, the damage state in each stage was determined, and the damage instability criterion was given. The effects of interfacial tensile strength and shear strength on the damage process of PBX were studied. On this basis, serrated and hemispherical structures interface of PBX has been developed, which affects the damage process and instability during the loading process.The results indicate that damage state response of PBX experiences the process of stable load bearing,unstable propagation, and complete failure. At the critical moment of instability, the overall equivalent effective strain of material reaches 3024 με and instability loading displacement reaches 0.39 mm. The increase of interfacial tensile strength and shear strength significantly inhibits the damage of PBX. The effect of interfacial shear strength on critical instability of PBX is approximately 1.7 times that of the interfacial tensile strength. Further, interface opening along the normal direction is the main damage form at the interface. Serrated and hemispherical rough interfaces can significantly inhibit propagation of cracks, and the load bearing capacity is improved by 22% and 9.7%, respectively. Appropriate improvement of the roughness of the interface structure can effectively improve the mechanical properties. It is significantly important to have a better understanding of deformation, damage and failure mechanisms of PBX and to improve our predictive ability.
基金Supported by The Chonnam National University Hospital Biomedical Research Institute,No.BCRI22023。
文摘BACKGROUND Atlantoaxial rotatory subluxation(AARS)is an uncommon disease with a greater prevalence among children than adults,and it is mostly associated with trauma.Iatrogenic spinal injury accounts for a low percentage of injuries.However,in AARS,20%-40%of cases are associated with surgery,and 48%are caused by infection.Here,we describe our experience with a case of iatrogenic AARS after general anesthesia.CASE SUMMARY A 12-year-old girl presented with right-sided torticollis and cervical motion limit.The patient had undergone thyroidectomy 2 mo ago.Computed tomography revealed AARS with bilateral locked facets.Following the failure of repeated external reduction under general anesthesia,the patient underwent an open surgical reduction.The patient gained atlantoaxial alignment without any complications.Follow-up radiographs showed a normal appearance without instability.The cervical spine of children is more predisposed to injury due to anatomical and biomechanical differences.AARS secondary to infection and surgery is known as Grisel’s syndrome,which involves non-traumatic AARS.Several cases of AARS after surgery and other procedures with no evidence of inflammation have been reported.Our experience shows that surgery requiring hyperextension of the neck after general anesthesia should also be included as a risk factor.CONCLUSION Surgeons and anesthesiologists should be careful not to excessively extend the neck during pediatric surgery.Moreover,clinicians caring for pediatric patients with recent head and neck procedures must be aware of common AARS presentations.
基金the National Natural Science Foundation of China(Grant No.11805116)the Natural Science Basic Research Plan in Shaanxi Province,China(Grant No.2023-JC-YB-037).
文摘We study modulational instability of a resonantly polariton condensate in a discrete lattice.Employing a discrete gain-saturation model,we derive the dispersion relation for the modulational instability by means of the linear-stability analysis.Effects of the pumping strength,the nonlinearity,the strength of the detuning,and the coupling strength on the modulation instability are investigated.It is found that the interplay between these parameters will dramatically change the modulational instability condition.We believe that the predicted results in this work can be useful for future possible experiment of exciton-polariton condensate in lattices.
基金financial support of German Research Foundation (DFG)(Grant Nr. YI103/3-1 and AL1343/8-1)。
文摘Plastic instability, called Portevin-Le-Chatelier(PLC) effect, manifests itself as an unstable plastic flow during tensile tests of structural materials. This phenomenon has a strong influence on diverse properties, leading to unexpected vulnerabilities in the service environment.Among various magnesium-based alloys, PLC phenomenon is most prominently observed in the Mg-Mn-Nd alloy under elevated temperature and low strain rate conditions. An important aim of the study is to clarify and compare the significance of the RE and Ca addition, which are known to cause a formation of a largely weakened non-basal type texture, in the occurrence of plastic instability. Due to the PLC phenomenon, there is a risk of weakening texture and formability improvement by the addition of RE and Ca elements in Mg alloys. Based on the understanding of the role of Nd to the PLC phenomenon in Mg-Mn alloy identified in previous studies, the PLC characteristics according to alloying elements and deformation conditions were compared and analyzed. To identify the micromechanical mechanisms of the PLC phenomenon, varies in the microstructure and mechanical properties during deformation of Mg-Mn binary and Ca or Nd-containing Mg-Mn-based ternary alloys in various conditions were systemically analyzed. The addition of Ca did not show a marked PLC effect due to the formation of low number density Mn-Ca and Ca-Ca solute clusters and an unbalanced Mn:Ca ratio. In contrast, the addition of Nd leads to the formation of a higher number density of Nd-Nd and Mn-Nd solute clusters than that of Ca-Ca and Mn-Ca solute clusters of the Mg-Mn-Ca alloy, resulting in a stable solute-dislocation interaction atmosphere under specific ranges of deformation temperature and strain rate. The deformation in the regime of PLC phenomenon, results in a decrease in ductility and an increase in strength, despite deformation at elevated temperatures with maintaining the weakened texture.
