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1.
Brain Spine ; 4: 102852, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39036750

RESUMO

Introduction: This study is a systematic review and meta-analysis that investigates the efficacy of different surgical methods for treating cervical disc herniation or cervical foraminal stenosis. Research question: The research aimed to compare the efficacy of Minimally Invasive Posterior Cervical Foraminotomy (MI-PCF) with anterior approaches, namely Anterior Cervical Discectomy and Fusion (ACDF) and Cervical Disc Arthroplasty (CDA). Material and methods: The study included a comprehensive review of eight articles that compared ACDF and MI-PCF, and four articles that compared CDA to MI-PCF. Results: The results indicated no significant difference in surgical duration, hospital stay, complication rates, and reoperation rates between MI-PCF and ACDF. However, when comparing CDA with MI-PCF, it was found that CDA had a higher complication rate, while MI-PCF had a higher reoperation rate. Discussion and conclusion: Despite these findings, the study recommends MI-PCF as the preferred surgical method for cervical radiculopathy, owing to the advancements in minimally invasive techniques. However, these findings are preliminary, and further research with longer follow-up periods and larger sample sizes is necessary to confirm these findings and to further explore the potential advantages and disadvantages of these surgical methods.

2.
Artigo em Inglês | MEDLINE | ID: mdl-39024084

RESUMO

Distributed stochastic optimization (DSO) with local set constraints and coupled inequality constraints over a multiagent network is considered in this article. Usually, such problems are tackled by projected primal-dual methods, which require expensive projection operations when set constraints are complicated. In this context, this article focuses on the Frank-Wolfe (FW) framework, which provides computational simplicity by avoiding expensive projection operations, for solving DSO with local set and coupled inequality constraints. By combining recursive momentum and weighted averaging, this article proposes a distributed stochastic FW primal-dual algorithm (DSFWPD), which is the first stochastic FW solver for DSO problems with coupled constraints. The proposed algorithm achieves zero constraint violation on average with a sublinear decay of the optimality gap over a directed and time-varying network. The efficacy of DSFWPD is demonstrated by several numerical experiments.

3.
J Cell Mol Med ; 27(3): 456-469, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36651490

RESUMO

Among breast cancer patients, metastases are the leading cause of death. Despite decades of effort, little progress has been made to improve the treatment of breast cancer metastases, especially triple-negative breast cancer (TNBC). The extracellular matrix plays an important role in tumour growth and metastasis by causing its deposition, remodelling, and signalling. As we know, the process of fibrosis results in excessive amounts of extracellular matrix being deposited within the cells. So, it will be interesting to study if the use of anti-fibrotic drugs in combination with conventional chemotherapy drugs can produce synergistic antitumor effects. In this study, we assessed the efficacy of Pirfenidone (PFD), an FDA-approved medication for the treatment of idiopathic pulmonary fibrosis, on TNBC cells as well as its anti-tumour effects in xenograft tumour model. PFD inhibited in a dose-dependent manner breast cancer cell proliferation, migration, and invasion, while promoted their apoptosis in vitro. PFD also suppressed TGF-ß-induced activation of Smad signalling pathway and expression level of EMT-inducing transcription factors (e.g. SNAI2, TWIST1, ZEB1) as well as the mesenchymal genes such as VIMENTIN and N-Cadherin. On the contrary, the expression level of epithelial marker gene E-Cadherin was up-regulated in the presence of PFD. In vivo, PFD alone exerted a milder but significant anti-tumour effect than the chemotherapy drug nanoparticle albumin-bound paclitaxel (nab-PTX) did in the breast cancer xenograft mouse model. Interestingly, PFD synergistically boosted the cancer-killing effect of nab-PTX. Furthermore, Our data suggest that PFD suppressed breast cancer metastasis by inhibiting the activity of the TGFß/SMAD pathway.


Assuntos
Fator de Crescimento Transformador beta , Neoplasias de Mama Triplo Negativas , Animais , Humanos , Camundongos , Linhagem Celular Tumoral , Movimento Celular , Transição Epitelial-Mesenquimal , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Proteínas Smad/metabolismo
4.
IEEE Trans Neural Netw Learn Syst ; 34(9): 5310-5321, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35536804

RESUMO

This article proposes a distributed stochastic algorithm with variance reduction for general smooth non-convex finite-sum optimization, which has wide applications in signal processing and machine learning communities. In distributed setting, a large number of samples are allocated to multiple agents in the network. Each agent computes local stochastic gradient and communicates with its neighbors to seek for the global optimum. In this article, we develop a modified variance reduction technique to deal with the variance introduced by stochastic gradients. Combining gradient tracking and variance reduction techniques, this article proposes a distributed stochastic algorithm, gradient tracking algorithm with variance reduction (GT-VR), to solve large-scale non-convex finite-sum optimization over multiagent networks. A complete and rigorous proof shows that the GT-VR algorithm converges to the first-order stationary points with O(1/k) convergence rate. In addition, we provide the complexity analysis of the proposed algorithm. Compared with some existing first-order methods, the proposed algorithm has a lower O(PMϵ-1) gradient complexity under some mild condition. By comparing state-of-the-art algorithms and GT-VR in numerical simulations, we verify the efficiency of the proposed algorithm.

5.
Int J Rheum Dis ; 26(1): 160-163, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36261877

RESUMO

We report a case of late-onset Schnitzler syndrome successfully treated with Janus-activated kinase (JAK) inhibitors and colchicine. Schnitzler syndrome should be considered for recurrent chronic urticaria when accompanied by fever, fatigue, rapid weight loss, and poor response to antihistamine treatment. Skin biopsy, bone marrow biopsy, and electrophoresis help confirm the diagnosis. Early diagnosis and treatment can lead to complete resolution of symptoms. Besides interleukin (IL)-1 and IL-6 inhibitors, JAK inhibitors and colchicine may be considered as other choices of treatment.


Assuntos
Síndrome de Schnitzler , Urticária , Humanos , Síndrome de Schnitzler/diagnóstico , Síndrome de Schnitzler/tratamento farmacológico , Colchicina/uso terapêutico , Urticária/diagnóstico , Piperidinas/uso terapêutico , Interleucina-1
6.
IEEE Trans Cybern ; 53(2): 1195-1207, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34460410

RESUMO

In this article, the distributed cooperative control problem of redundant mobile manipulators is investigated. A novel method is proposed to solve the problem by integrating formation control with constrained optimization, which not only transports the object along a reference trajectory in a distributed manner but also obtains the dexterous joint postures and end-effector displacements under safety constraints for collision avoidance. For the constrained optimization, the cost function and safety constraints are designed to quantify the mobility and manipulability of mobile manipulators, and collision-free working ranges with the object and obstacles, respectively. A discontinuous projected primal-dual algorithm with damping terms is proposed to solve the constrained optimization problem, providing the joint postures and end-effector displacements, which minimize the cost function and satisfy safety constraints. For the formation control, a finite-time control law, guided by end-effector displacements from the primal-dual algorithm, is developed in order to transport the object by establishing a prescribed formation and moving its centroid to track the reference trajectory. The cooperative manipulation is therefore achieved by the proposed method, which is further validated through numerical simulations.

7.
Artigo em Inglês | MEDLINE | ID: mdl-36070265

RESUMO

The nonsmooth finite-sum minimization is a fundamental problem in machine learning. This article develops a distributed stochastic proximal-gradient algorithm with random reshuffling to solve the finite-sum minimization over time-varying multiagent networks. The objective function is a sum of differentiable convex functions and nonsmooth regularization. Each agent in the network updates local variables by local information exchange and cooperates to seek an optimal solution. We prove that local variable estimates generated by the proposed algorithm achieve consensus and are attracted to a neighborhood of the optimal solution with an O((1/T)+(1/√T)) convergence rate, where T is the total number of iterations. Finally, some comparative simulations are provided to verify the convergence performance of the proposed algorithm.

8.
Small ; 18(30): e2201056, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35652171

RESUMO

Bone repair in real time is a challenging medical issue for elderly patients; this is mainly because aged bone marrow mesenchymal stem cells (BMSCs) possess limited osteogenesis potential and repair capacity. In this study, triboelectric stimulation technology is used to achieve bone repair via mechanosensation of Piezo1 by fabricating a wearable pulsed triboelectric nanogenerator (WP-TENG) driven by human body movement. A peak value of 30 µA has the optimal effects to rejuvenate aged BMSCs, enhance their osteogenic differentiation, and promote human umbilical vein endothelial cell tube formation. Further, previous studies demonstrate that triboelectric stimulation of a WP-TENG can reinforce osteogenesis of BMSCs and promote the angiogenesis of human umbilical vein endothelial cells (HUVECs). Mechanistically, aged BMSCs are rejuvenated by triboelectric stimulation via the mechanosensitive ion channel Piezo1. Thus, the osteogenesis potential of BMSCs is enhanced and the tube formation capacity of HUVECs is improved, which is further confirmed by augmented bone repair and regeneration in in vivo investigations. This study provides a potential signal transduction mechanism for rejuvenating aged BMSCs and a theoretical basis for bone regeneration using triboelectric stimulation generated by a WP-TENG.


Assuntos
Células-Tronco Mesenquimais , Dispositivos Eletrônicos Vestíveis , Idoso , Células da Medula Óssea , Diferenciação Celular/fisiologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Canais Iônicos , Osteogênese
9.
Int J Mol Sci ; 23(11)2022 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-35682767

RESUMO

The basolateral amygdala (BLA) is one of the key brain areas involved in aversive learning, especially fear memory formation. Studies of aversive learning in the BLA have largely focused on neuronal function, while the role of BLA astrocytes in aversive learning remains largely unknown. In this study, we manipulated the BLA astrocytes by expressing the Gq-coupled receptor hM3q and discovered that astrocytic Gq modulation during fear conditioning promoted auditorily cued fear memory but did not affect less stressful memory tasks or induce anxiety-like behavior. Moreover, chemogenetic activation of BLA astrocytes during memory retrieval had no effect on fear memory expression. In addition, astrocytic Gq activation increased c-Fos expression in the BLA and the medial prefrontal cortex (mPFC) during fear conditioning, but not in the home cage. Combining these results with retrograde virus tracing, we found that the activity of mPFC-projecting BLA neurons showed significant enhancement after astrocytic Gq activation during fear conditioning. Electrophysiology recordings showed that activating astrocytic Gq in the BLA promoted spike-field coherence and phase locking percentage, not only within the BLA but also between the BLA and the mPFC. Finally, direct chemogenetic activation of mPFC-projecting BLA neurons during fear conditioning enhanced cued fear memory. Taken together, our data suggest that astrocytes in the BLA may contribute to aversive learning by modulating amygdala-mPFC communication.


Assuntos
Complexo Nuclear Basolateral da Amígdala , Tonsila do Cerebelo/fisiologia , Astrócitos , Complexo Nuclear Basolateral da Amígdala/fisiologia , Medo/fisiologia , Córtex Pré-Frontal/fisiologia
10.
World Neurosurg ; 161: e134-e145, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35093578

RESUMO

OBJECTIVE: To compare the clinical outcomes of uniportal and biportal lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) in patients with lumbar spinal stenosis. METHODS: A retrospective pair-matched case-control analysis of 72 patients with lumbar spinal stenosis was performed. According to the surgical procedure used, the patients were classified into 2 groups: 1) uniportal LE-ULBD and 2) biportal LE-ULBD. Clinical outcomes were assessed using the visual analog scale score, Oswestry Disability Index score, and Macnab criteria, and the results were compared between the groups. RESULTS: All patients were successfully treated with either uniportal or biportal LE-ULBD. The surgical duration in the biportal LE-ULBD group was significantly shorter than in the uniportal LE-ULBD group (P < 0.001). The time to ambulation and the length of hospitalization in the 2 groups were not significantly different. The visual analog scale and Oswestry Disability Index scores improved significantly after surgery in both groups (P < 0.001). Based on the Macnab criteria, 33 (91.7%) patients in the uniportal LE-ULBD group and 34 (94.4%) patients in the biportal LE-ULBD group were rated as having an excellent or good outcome. Additionally, intraoperative epineurium injury was observed in both the LE-ULBD groups. CONCLUSIONS: Both uniportal and biportal LE-ULBD procedures are safe and effective for treating patients with lumbar spinal stenosis. It is more feasible to decompress the spinal canal during biportal LE-ULBD than during uniportal LE-ULBD.


Assuntos
Estenose Espinal , Estudos de Casos e Controles , Descompressão Cirúrgica/métodos , Humanos , Laminectomia/métodos , Vértebras Lombares/cirurgia , Estudos Retrospectivos , Estenose Espinal/diagnóstico por imagem , Estenose Espinal/cirurgia , Resultado do Tratamento
11.
Orthop Surg ; 14(2): 280-289, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34914186

RESUMO

OBJECTIVE: This retrospective case-control study aimed to evaluate and compare the clinical outcomes of full-endoscopic visualized foraminoplasty and discectomy (FEVFD) with microdiscectomy (MD) for lumbar disc herniation (LDH). METHODS: Data from 198 patients who presented with LDH between January 2016 and December 2017 treated by either FEVFD or MD were retrospectively analyzed. The inclusion criteria were single-level LDH, unilateral radiating leg pain with or without positive Lasegue's sign, and failure of standard conservative treatment for at least 12 weeks. The patients were categorized into an FEVFD group (n = 102) or an MD group (n = 96), according to the surgical procedure performed. Operative time, time in bed after surgery, postoperative hospitalization time, complications, and reoperations were recorded. Visual analog scales (VAS) for leg and back pain, Oswestry Disability index (ODI), 36-Item Short-Form Health Survey physical function (SF36-PF), and bodily pain (SF36-BP) scores were assessed and compared between the two groups. RESULTS: The demographic data and baseline characteristics of the two groups were not significantly different. Operative time for the FEVFD group (73.82 ± 20.73 min) was longer than that for the MD group (64.74 ± 17.37 min) (P = 0.003), and fluoroscopy time for the FEVFD group (1.71 ± 0.58s) was longer than that for the MD group (1.30 ± 0.33s) (P < 0.001). However, time in bed experienced in the FEVFD group (8.51 ± 2.10 h) was less than that in the MD group (9.24 ± 2.01 h) (P = 0.014), and postoperative hospitalization time experienced in the FEVFD group (2.89 ± 0.83d) was also shorter than that in the MD group (4.94 ± 1.35d) (P < 0.001). All patients completed 24 months of follow-up. Postoperative scores at each follow-up for the VAS for leg and back pain, ODI, SF36-PF, and SF36-BP all improved significantly for both groups, as compared to the preoperative data (P < 0.05). The mean preoperative and postoperative scores for the VAS for leg and back pain, ODI, SF36-PF, and SF36-BP were not significantly different between the two groups. According to the modified MacNab criteria, the outcomes of the procedures were rated as excellent or good by 92.16% and 93.75% of the patients in the FEVFD and MD groups, respectively. One patient suffered a nerve root injury during the discectomy, one patient suffered from a dural tear, and two patients suffered from a residual herniation in the FEVFD group. One patient in the MD group suffered from poor wound healing. Moreover, recurrence happened in two cases in the FEVFD group, and in one case in the MD group. CONCLUSION: FEVFD and MD are both reliable techniques for the treatment of symptomatic LDH. FEVFD resulted in a more rapid recovery and equivalent clinical outcomes after 24 months of follow-up.


Assuntos
Discotomia Percutânea , Deslocamento do Disco Intervertebral , Estudos de Casos e Controles , Discotomia/efeitos adversos , Discotomia/métodos , Discotomia Percutânea/métodos , Endoscopia/métodos , Humanos , Deslocamento do Disco Intervertebral/diagnóstico por imagem , Deslocamento do Disco Intervertebral/cirurgia , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Estudos Retrospectivos , Resultado do Tratamento
12.
IEEE Trans Cybern ; 52(3): 1924-1935, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32609618

RESUMO

This article proposes a distributed optimization design to compute continuous-time algebraic Riccati inequalities (ARIs), where the information of matrices is distributed among agents. We propose a design procedure to tackle the nonlinearity, the inequality, and the coupled information structure of ARI; then, we design a distributed algorithm based on an optimization approach and analyze its convergence properties. The proposed algorithm is able to verify whether ARI is feasible in a distributed way and converges to a solution if ARI is feasible for any initial condition.

13.
IEEE Trans Cybern ; 52(2): 937-946, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32452786

RESUMO

The problem of solving discrete-time Lyapunov equations (DTLEs) is investigated over multiagent network systems, where each agent has access to its local information and communicates with its neighbors. To obtain a solution to DTLE, a distributed algorithm with uncoordinated constant step sizes is proposed over time-varying topologies. The convergence properties and the range of constant step sizes of the proposed algorithm are analyzed. Moreover, a linear convergence rate is proved and the convergence performances over dynamic networks are verified by numerical simulations.

14.
Oxid Med Cell Longev ; 2021: 8884922, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33628392

RESUMO

Mechanical stimulation plays a crucial part in the development of intervertebral disc degeneration (IDD). Extracellular matrix (ECM) stiffness, which is a crucial mechanical microenvironment of the nucleus pulposus (NP) tissue, contributes to the pathogenesis of IDD. The mechanosensitive ion channel Piezo1 mediates mechanical transduction. This study purposed to investigate the function of Piezo1 in human NP cells under ECM stiffness. The expression of Piezo1 and the ECM elasticity modulus increased in degenerative NP tissues. Stiff ECM activated the Piezo1 channel and increased intracellular Ca2+ levels. Moreover, the activation of Piezo1 increased intracellular reactive oxygen species (ROS) levels and the expression of GRP78 and CHOP, which contribute to oxidative stress and endoplasmic reticulum (ER) stress. Furthermore, stiff ECM aggravated oxidative stress-induced senescence and apoptosis in human NP cells. Piezo1 inhibition alleviated oxidative stress-induced senescence and apoptosis, caused by the increase in ECM stiffness. Finally, Piezo1 silencing ameliorated IDD in an in vivo rat model and decreased the elasticity modulus of rat NP tissues. In conclusion, we identified the mechanosensitive ion channel Piezo1 in human NP cells as a mechanical transduction mediator for stiff ECM stimulation. Our results provide novel insights into the mechanism of mechanical transduction in NP cells, with potential for treating IDD.


Assuntos
Apoptose , Senescência Celular , Matriz Extracelular/metabolismo , Degeneração do Disco Intervertebral/patologia , Canais Iônicos/metabolismo , Mecanotransdução Celular , Estresse Oxidativo , Adolescente , Adulto , Idoso , Animais , Fenômenos Biomecânicos , Progressão da Doença , Chaperona BiP do Retículo Endoplasmático , Estresse do Retículo Endoplasmático , Feminino , Técnicas de Silenciamento de Genes , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Núcleo Pulposo/patologia , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Regulação para Cima , Adulto Jovem
15.
Chemosphere ; 272: 129629, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33486458

RESUMO

Advanced oxidation processes (AOPs) based on persulfate (PS) has attracted great attention due to its high efficiency for degradation of organic pollutants. Manganese-based materials have been considered as the desirable catalysts for in-situ chemical oxidation since they are abundant in the earth's crust and environment-friendly. In this study, manganese oxyhydroxide (MnOOH) was used as an activator for PS to degrade p-chloroaniline (PCA) from wastewater. The effects of MnOOH dosage, PS dosage and initial pH on PCA degradation performance were studied. Experimental results showed that PCA degradation efficiency was enhanced by higher MnOOH and PS addition, and the degradation efficiency was slightly inhibited as the initial pH increased from 3 to 9. MnOOH showed excellent stability and reusability when used as the activator of PS. In addition, a comprehensive study was conducted to determine the PS activation mechanism. The results revealed that PS activation by MnOOH followed a nonradical mechanism. No 1O2 was generated, and the main active substance in the reaction was the activated PS molecule on the surface of MnOOH. The hydroxyl group on the catalyst surface acted as a bridge connecting PS and the catalyst, leading to the activation of PS. The intermediates during PCA degradation were also analyzed, and three possible degradation pathways of PCA were proposed. This study expects to deepen the understanding of the PS activation mechanism by manganese oxide, and provides technical support for the practical application of AOPs of manganese-based materials for wastewater treatment.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Manganês , Compostos Orgânicos , Oxirredução , Sulfatos , Poluentes Químicos da Água/análise
16.
Front Mol Biosci ; 7: 586344, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33330624

RESUMO

Head and neck squamous cell carcinoma (HNSCC) is the eighth leading cancer by incidence worldwide, with approximately 700,000 new cases in 2018 (accounting for 11% of all cancers). The occurrence and development of tumors are closely related to the immunological function of the body and sensitivity to treatment schemes as well as prognosis. It is urgent for clinicians to systematically study patients' immune gene maps to help select a treatment plan and analyze the potential to cure HNSCC. Here, the transcriptomic data of HNSCC samples were downloaded from The Cancer Genome Atlas (TCGA), and 4,793 genes differentially expressed in normal and cancer tissues of HNSCC were identified, including 1,182 downregulated and 3,611 upregulated genes. From these genes, 400 differentially expressed immune-related genes (IRGs) were extracted, including 95 downregulated genes and 305 upregulated genes. The prognostic values of IRGs were evaluated by univariate Cox analysis, and 236 genes that were significantly related to the overall survival (OS) of patients were identified. The signaling pathways that play roles in the prognosis of IRGs were investigated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, and the expression profiles of IRGs and OS in 499 HNSCC patients based on TCGA dataset were integrated. Potential molecular mechanisms and characteristics of these HNSCC-specific IRGs were further explored with the help of a new prognostic index based on IRGs developed by least absolute shrinkage and selection operator (LASSO) Cox analysis. A total of 64 hub genes (IRGs associated with prognosis) were markedly associated with the clinical outcome of HNSCC patients. KEGG functional enrichment analysis revealed that these genes were actively involved in several pathways, e.g., cytokine-cytokine receptor interaction, T-cell receptor signaling, and natural killer cell-mediated cytotoxicity. IRG-based prognostic signatures performed moderately in prognostic predictions. Interestingly, the prognostic index based on IRGs reflected infiltration by several types of immune cells. These data screened several IRGs of clinical significance and revealed drivers of the immune repertoire, demonstrating the importance of a personalized IRG-based immune signature in the recognition, surveillance, and prognosis of HNSCC.

17.
Materials (Basel) ; 13(21)2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33172199

RESUMO

Bulk FeSe superconductors of the iron-based (IBS) "11" family containing various additions of silver were thoroughly investigated concerning the microstructure using optical microscopy and electron microscopy (TEM and SEM). The measurements of electrical resistivity were performed through the four-point technique in the temperature interval T= 2-150 K. The Aslamazov-Larkin model was employed to analyze the fluctuation-induced conductivity (FIC) in all acquired measurements. In all studied products, we found that the FIC curves consist of five different regimes of fluctuation, viz. critical region (CR), three-dimensional (3D), two-dimensional (2D), one-dimensional (1D), and shortwave fluctuation (SWF) regimes. The critical current density (Jc), the lower and upper critical magnetic fields (Bc1 and Bc2), the coherence length along the c-axis at zero-temperature (ξc(0)), and further parameters were assessed with regards to the silver amount within the products. The analyses discloses a diminution in the resistivity and a great reduction in ξc(0) with Ag addition. The optimal silver doping amount is achieved for 7 wt.%, which yields the best superconducting transition and the greatest Jc value.

18.
Artigo em Inglês | MEDLINE | ID: mdl-32766226

RESUMO

Posterior fixation is superior to anterior fixation in the correction of kyphosis and maintenance of spinal stability for the treatment of thoracic spinal tuberculosis. However, the process of selecting the appropriate spinal fixation method remains controversial, and preoperative biomechanical evaluation has not yet been investigated. In this study, we aimed to analyze the application of the assisted finite element analysis (FEA) and the three-dimensional (3D) printed model for the patient-specific preoperative planning of thoracic spinal tuberculosis. An adult patient with thoracic spinal tuberculosis was included. A finite element model of the T7-T11 thoracic spine segments was reconstructed to analyze the biomechanical effect of four different operative constructs. The von Mises stress values of the implants in the vertical axial load and flexion and extension conditions under a 400-N vertical axial pre-load and a 10-N⋅m moment were calculated and compared. A 3D printed model was used to describe and elucidate the patient's condition and simulate the optimal surgical design. According to the biomechanical evaluation, the patient-specific preoperative surgical design was prepared for implementation. The anterior column, which was reconstructed with titanium alloy mesh and a bone graft with posterior fixation using seven pedicle screws (M+P) and performed at the T7-T11 level, decreased the von Mises stress placed on the right rod, T7 pedicle screw, and T11 pedicle. Moreover, the M+P evaded the left T9 screw without load bearing. The 3D printed model and preoperative surgical simulation enhanced the understanding of the patient's condition and facilitated patient-specific preoperative planning. Good clinical results, including no complication of implants, negligible loss of the Cobb angle, and good bone fusion, were achieved using the M+P surgical design. In conclusion, M+P was recommended as the optimal method for preoperative planning since it enabled the preservation of the normal vertebra and prevented unnecessary internal fixation. Our study indicated that FEA and the assisted 3D printed model are tools that could be extremely useful and effective in the patient-specific preoperative planning for thoracic spinal tuberculosis, which can facilitate preoperative surgical simulation and biomechanical evaluation, as well as improve the understanding of the patient's condition.

19.
Comput Methods Biomech Biomed Engin ; 23(14): 1109-1116, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32633569

RESUMO

The purpose of this study was to use models of spine to compare range of motion and intradiscal pressure of adjacent segments performing anterior and/or posterior lumbar surgical approaches and predict potential risk of adjacent segment degeneration. A previously validated finite element model of the intact L1-S1 segments was used. Three different anterior and one posterior surgical fixation approaches for tuberculosis were performed in L3-L5. Three different anterior surgical models were constructed according to the anterior approaches involving debridement, bone graft with or without titanium mesh, and internal fixation with different number of screws and rods. The posterior surgical approach involved transforaminal lumbar interbody debridement, bone graft, and internal fixation. Range of motion and intradiscal pressure of segments adjacent to the fusion were assessed, and biomechanical influences were compared. Intradiscal pressure and range of motion of the adjacent L2/3 and L5/S1 increased during different physiological movements after anterior and/or posterior surgical approaches as compared to baseline values. Comparison between the biomechanical values assessed after different anterior surgical approaches yielded no significant difference. After anterior and posterior surgical approaches were performed on the same model, there were no significant differences in intradiscal pressure and range of motion of the adjacent L2/3 and L5/S1. Anterior and/or posterior lumbar surgical approaches increased range of motion and intradiscal pressure in L2/3 and L5/S1, suggesting each lumbar surgical approach assessed has the potential risk of adjacent segment degeneration. However, there were no significant differences between the biomechanical measurements across the different surgical approaches evaluated.


Assuntos
Análise de Elementos Finitos , Vértebras Lombares/fisiopatologia , Vértebras Lombares/cirurgia , Adulto , Fenômenos Biomecânicos/fisiologia , Humanos , Disco Intervertebral/fisiopatologia , Masculino , Pressão , Amplitude de Movimento Articular/fisiologia
20.
Orthop Surg ; 12(4): 1120-1130, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32524753

RESUMO

OBJECTIVE: To evaluate the efficacy and feasibility of minimally invasive oblique lumbar interbody debridement and fusion for the treatment of conservatively ineffective lumbar spondylodiscitis. METHODS: This is a retrospective study. Between December 2016 and November 2017, a total of 14 consecutive patients (eight males and six females, with an average age of 49.1 years, range from 42 to 74 years) with single-level lumbar spondylodiscitis were included in the study. The inclusion criteria include single-level spondylodiscitis without spinal deformity or epidural abscess, ineffective conservative treatment (continuously aggravated clinical symptoms and uncontrollable infective symptoms treated with antibiotics for more than 6 weeks), minimally invasive oblique lumbar interbody fusion surgery (Mis-OLIF) and iliac graft for the treatment of lumbar spondylodiscitis, and postoperative follow-up >12 months. Each patient was treated Mis-OLIF. Clinical outcomes including demographic characteristics, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), visual analog scale (VAS), the Oswestry Disability Index (ODI), American Spinal Injury Association neurological classification, and lordotic angle were analyzed. RESULTS: The infectious levels included L1/2 (one patient), L2/3 (two patients), L3/4 (eight patients), and L4/5 (three patients). The pathogens found in these patients included Staphylococcus aureus (5), brucellosis (6), and enterobacterium (2). The pathogen was undefined in one patient. The mean duration of the surgery, mean blood loss, and mean follow-up were 89.3 ± 17.5 min, 155.0 ± 49.4 mL, and 16.8 ± 4.2 months, respectively. The ESR and CRP decreased after Mis-OLIF and antibiotic administration. The average preoperative VAS score was 6.9 ± 0.9, then decreased to 3.0 ± 1.0 (t = 14.18, P < 0.001) and 0.6 ± 0.7 (t = 20.68, P < 0.001) before discharge and at final follow-up, respectively. The average preoperative ODI score was 58.4 ± 13.0, then decreased to 28.3 ± 6.1 (t = 18.6, P < 0.001) and 8.0 ± 4.6 (t = 22.7, P < 0.001) before discharge and at final follow-up, respectively. None of the patients developed postoperative ileus, vascular injury, nerve injury, and ureteral injury. One patient suffered incision-related complication that healed by debridement and dressing change. One patient developed subsidence of autologous iliac bone before discharge and achieved complete bony fusion after staying in bed and fixing it with a brace at 3 months follow-up. All patients achieved bony fusion at final follow-up. CONCLUSION: Mis-OLIF without anterior or posterior instrumentation and iliac graft is an effective and viable approach for the treatment of conservatively ineffective lumbar spondylodiscitis without spinal deformity or epidural abscess.


Assuntos
Desbridamento/métodos , Discite/cirurgia , Vértebras Lombares/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Fusão Vertebral/métodos , Adulto , Idoso , Transplante Ósseo , Avaliação da Deficiência , Feminino , Humanos , Ílio/transplante , Masculino , Pessoa de Meia-Idade , Medição da Dor , Estudos Retrospectivos
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