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1.
Artigo em Inglês | MEDLINE | ID: mdl-38563706

RESUMO

OBJECTIVE: The objective is to explore clinicopathological characteristics, diagnosis, differential diagnoses, treatment, and prognoses of placental chorioangioma (PCA). MATERIALS AND METHODS: The pathological data of 30 cases of PCA were collected; the color Doppler ultrasound, Down's screening, fetal survival, and pathological characteristics were observed; and the literature was reviewed. RESULTS: Of the 30 patients, the ages ranged from 20 to 38 years, with an average of 29.6 years. Pregnancy comorbidity occurred in 14 patients; intrauterine fetal death occurred in 4; the gross appearance of the tumor: a reddish-brown nodule, slightly round, 0.5-8 cm in diameter, can be seen on the cut surface of the placenta Pregnancy comorbidity occurred in 14 patients and intrauterine fetal death in 4. On sectioning the placenta, tumors grossly appeared as reddish-brown nodules, slightly round and ranging in diameter from 0.5 to 8 cm. Microscopically, the tumor has small, densely packed capillaries with fibrous connective tissue in the stroma. There were 10 cases with high risk of Down's syndrome screening, and the immunophenotype CD34 (+) and Ki-67 proliferation index were less than 10%. CONCLUSIONS: PCA is rare and may be misdiagnosed as malignant tumor, which may be related to pregnancy comorbidity and high risk of Down's screening, so improving the understanding of PCA can provide the basis for clinical diagnosis and intervention. PCA is a rare tumor which may be misdiagnosed as a malignancy. It may be related to pregnancy comorbidity and high risk of Down's screening. Improving the understanding of PCA could provide the basis for clinical diagnosis and intervention.

2.
Sensors (Basel) ; 23(23)2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38067922

RESUMO

Cervical degenerative disc diseases such as myelopathy and radiculopathy often require conventional treatments like artificial cervical disc replacement or anterior cervical discectomy and fusion (ACDF). When designing a medical device, like the stand-alone cage, there are many design inputs to consider. However, the precise biomechanics of the force between the vertebrae and implanted devices under certain conditions require further investigation. In this study, a new method was developed to evaluate the pressure between the vertebrae and implanted devices by embedding a sensor array into a 3D-printed C2-C3 cervical spine. The 3D-printed cervical spine model was subjected to a range of axial loads while under flexion, extension, bending and compression conditions. Cables were used for the application of a preload and a robotic arm was used to recreate the natural spine motions (flexion, extension, and bending). To verify and predict the total pressure between the vertebrae and the implanted devices, a 3D finite element (FE) numerical mathematical model was developed. A preload was represented by applying 22 N of force on each of the anterior tubercles for the C2 vertebra. The results of this study suggest that the sensor is useful in identifying static pressure. The pressure with the robot arm was verified from the FE results under all conditions. This study indicates that the sensor array has promising potential to reduce the trial and error with implants for various surgical procedures, including multi-level artificial cervical disk replacement and ACDF, which may help clinicians to reduce pain, suffering, and costly follow-up procedures.


Assuntos
Degeneração do Disco Intervertebral , Fusão Vertebral , Humanos , Fusão Vertebral/métodos , Vértebras Cervicais/cirurgia , Degeneração do Disco Intervertebral/cirurgia , Discotomia/métodos , Fenômenos Biomecânicos , Amplitude de Movimento Articular , Impressão Tridimensional
3.
Front Bioeng Biotechnol ; 11: 1237702, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37790254

RESUMO

The study aimed to investigate the impact of posterior element and ligament removal on the maximum von Mises stress, and maximum shear stress of the eight-layer annulus for treating stenosis at the L3-L4 and L4-L5 levels in the lumbar spine. Previous studies have indicated that laminectomy alone can result in segmental instability unless fusion is performed. However, no direct correlations have been established regarding the impact of posterior and ligament removal. To address this gap, four models were developed: Model 1 represented the intact L2-L5 model, while model 2 involved a unilateral laminotomy involving the removal of a section of the L4 inferior lamina and 50% of the ligament flavum between L4 and L5. Model 3 consisted of a complete laminectomy, which included the removal of the spinous process and lamina of L4, as well as the relevant connecting ligaments between L3-L4 and L4-L5 (ligament flavum, interspinous ligament, supraspinous ligament). In the fourth model, a complete laminectomy with 50% facetectomy was conducted. This involved the same removals as in model 3, along with a 50% removal of the inferior/superior facets of L4 and a 50% removal of the facet capsular ligaments between L3-L4 and L4-L5. The results indicated a significant change in the range of motion (ROM) at the L3-L4 and L4-L5 levels during flexion and torque situations, but no significant change during extension and bending simulation. The ROM increased by 10% from model 1 and 2 to model 3, and by 20% to model 4 during flexion simulation. The maximum shear stress and maximum von-Mises stress of the annulus and nucleus at the L3-L4 levels exhibited the greatest increase during flexion. In all eight layers of the annulus, there was an observed increase in both the maximum shear stress and maximum von-Mises stress from model 1&2 to model 3 and model 4, with the highest rate of increase noted in layers 7&8. These findings suggest that graded posterior element and ligament removal have a notable impact on stress distribution and range of motion in the lumbar spine, particularly during flexion.

4.
Front Robot AI ; 10: 1212768, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37457389

RESUMO

Individuals who have suffered neurotrauma like a stroke or brachial plexus injury often experience reduced limb functionality. Soft robotic exoskeletons have been successful in assisting rehabilitative treatment and improving activities of daily life but restoring dexterity for tasks such as playing musical instruments has proven challenging. This research presents a soft robotic hand exoskeleton coupled with machine learning algorithms to aid in relearning how to play the piano by 'feeling' the difference between correct and incorrect versions of the same song. The exoskeleton features piezoresistive sensor arrays with 16 taxels integrated into each fingertip. The hand exoskeleton was created as a single unit, with polyvinyl acid (PVA) used as a stent and later dissolved to construct the internal pressure chambers for the five individually actuated digits. Ten variations of a song were produced, one that was correct and nine containing rhythmic errors. To classify these song variations, Random Forest (RF), K-Nearest Neighbor (KNN), and Artificial Neural Network (ANN) algorithms were trained with data from the 80 taxels combined from the tactile sensors in the fingertips. Feeling the differences between correct and incorrect versions of the song was done with the exoskeleton independently and while the exoskeleton was worn by a person. Results demonstrated that the ANN algorithm had the highest classification accuracy of 97.13% ± 2.00% with the human subject and 94.60% ± 1.26% without. These findings highlight the potential of the smart exoskeleton to aid disabled individuals in relearning dexterous tasks like playing musical instruments.

5.
Asian Spine J ; 17(5): 949-963, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37408489

RESUMO

The cervical spine poses many complex challenges that require complex solutions. Anterior cervical discectomy and fusion (ACDF) has been one such technique often employed to address such issues. In order to address the problems with ACDF and assess the modifications that have been made to the technique over time, finite element analyses (FEA) have proven to be an effective tool. The variations of cervical spine FEA models that have been produced over the past couple of decades, particularly more recent representations of more complex geometries, have not yet been identified and characterized in any literature. Our objective was to present material property models and cervical spine models for various simulation purposes. The outlining and refinement of the FEA process will yield more reliable outcomes and provide a stable basis for the modeling protocols of the cervical spine.

6.
Molecules ; 28(8)2023 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-37110759

RESUMO

Two-dimensional van der Waals (vdW) heterostructures are potential candidates for clean energy conversion materials to address the global energy crisis and environmental issues. In this work, we have comprehensively studied the geometrical, electronic, and optical properties of M2CO2/MoX2 (M = Hf, Zr; X = S, Se, Te) vdW heterostructures, as well as their applications in the fields of photocatalytic and photovoltaic using density functional theory calculations. The lattice dynamic and thermal stabilities of designed M2CO2/MoX2 heterostructures are confirmed. Interestingly, all the M2CO2/MoX2 heterostructures exhibit intrinsic type-II band structure features, which effectively inhibit the electron-hole pair recombination and enhance the photocatalytic performance. Furthermore, the internal built-in electric field and high anisotropic carrier mobility can separate the photo-generated carriers efficiently. It is noted that M2CO2/MoX2 heterostructures exhibit suitable band gaps in comparison to the M2CO2 and MoX2 monolayers, which enhance the optical-harvesting abilities in the visible and ultraviolet light zones. Zr2CO2/MoSe2 and Hf2CO2/MoSe2 heterostructures possess suitable band edge positions to provide the competent driving force for water splitting as photocatalysts. In addition, Hf2CO2/MoS2 and Zr2CO2/MoS2 heterostructures deliver a power conversion efficiency of 19.75% and 17.13% for solar cell applications, respectively. These results pave the way for exploring efficient MXenes/TMDCs vdW heterostructures as photocatalytic and photovoltaic materials.

7.
Eur Spine J ; 32(3): 957-968, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36708398

RESUMO

PURPOSE: Various factors have been examined in relation to cage subsidence risk, including cage material, cage geometry, bone mineral density, device type, surgical level, bone graft, and patient age. The present study aims to compare and synthesize the literature of both clinical and biomechanical studies to evaluate and present the factors associated with cage subsidence. METHODS: A comprehensive search of the literature from January 2003 to December 2021 was conducted using the PubMed and ScienceDirect databases by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Following the screening for inclusion and exclusion criteria, a total of 49 clinical studies were included. Correlations between clinical and biomechanical studies are also discussed. RESULTS: Patients treated with the cage and plate combination had a lower subsidence rate than patients with the stand-alone cage. Overall, Polyetheretherketone material was shown to have a lower subsidence rate than titanium and other materials. The subsidence rate was also higher when the surgery was performed at levels C5-C7 than at levels C2-C5. No significant correlation was found between age and cage subsidence clinically. CONCLUSIONS: Cage subsidence increases the stress on the anterior fixation system and may cause biomechanical instability. Severe cage subsidence decreases the Cobb angle and intervertebral height, which may cause destabilization of the implant system, such as screw/plate loosening or breakage of the screw/plate. Various factors have been shown to influence the risk of cage subsidence. Examining clinical research alongside biomechanical studies offers a more comprehensive understanding of the subject.


Assuntos
Discotomia , Polietilenoglicóis , Humanos , Discotomia/efeitos adversos , Cetonas , Placas Ósseas , Parafusos Ósseos
8.
Bioengineering (Basel) ; 11(1)2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38247901

RESUMO

Over the past few decades, there has been a growing popularity in utilizing finite element analysis to study the spine. However, most current studies tend to use one specimen for their models. This research aimed to validate multiple finite element models by comparing them with data from in vivo experiments and other existing finite element studies. Additionally, this study sought to analyze the data based on the gender and age of the specimens. For this study, eight lumbar spine (L2-L5) finite element models were developed. These models were then subjected to finite element analysis to simulate the six fundamental motions. CT scans were obtained from a total of eight individuals, four males and four females, ranging in age from forty-four (44) to seventy-three (73) years old. The CT scans were preprocessed and used to construct finite element models that accurately emulated the motions of flexion, extension, lateral bending, and axial rotation. Preloads and moments were applied to the models to replicate physiological loading conditions. This study focused on analyzing various parameters such as vertebral rotation, facet forces, and intradiscal pressure in all loading directions. The obtained data were then compared with the results of other finite element analyses and in vivo experimental measurements found in the existing literature to ensure their validity. This study successfully validated the intervertebral rotation, intradiscal pressure, and facet force results by comparing them with previous research findings. Notably, this study concluded that gender did not have a significant impact on the results. However, the results did highlight the importance of age as a critical variable when modeling the lumbar spine.

9.
Artigo em Inglês | MEDLINE | ID: mdl-38394399

RESUMO

ABSTRACT: Placental mesenchymal dysplasia is a rare disorder of the placenta with only a few reported cases. A case of interstitial dysplasia of the placenta was reported. The diagnosis and differential diagnosis were made by gross observation, microscopic findings, and immunohistochemistry.

10.
Asian Spine J ; 16(5): 615-624, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35263829

RESUMO

STUDY DESIGN: This study compares four cervical endplate removal procedures, validated by finite element models. PURPOSE: To characterize the effect of biomechanical strength and increased contact area on the maximum von Mises stress, migration, and subsidence between the cancellous bone, endplate, and implanted cage. OVERVIEW OF LITERATURE: Anterior cervical discectomy and fusion (ACDF) has been widely used for treating patients with degenerative spondylosis. However, no direct correlations have been drawn that incorporate the impact of the contact area between the cage and the vertebra/endplate. METHODS: Model 1 (M1) was an intact C2C6 model with a 0.5 mm endplate. In model 2 (M2), a cage was implanted after removal of the C4-C5 and C5-C6 discs with preservation of the osseous endplate. In model 3 (M3), 1 mm of the osseous endplate was removed at the upper endplate. Model 4 (M4) resembles M3, except that 3 mm of the osseous endplate was removed. RESULTS: The range of motion (ROM) at C2C6 in the M2-M4 models was reduced by at least 9º compared to the M1 model. The von Mises stress results in the C2C3 and C3C4 interbody discs were significantly smaller in the M1 model and slightly increased in the M2-M3 and M3-M4 models. Migration and subsidence decreased from the M2-M3 model, whereas further endplate removal increased the migration and subsidence as shown in the transition from M3 to M4. CONCLUSIONS: The M3 model had the least subsidence and migration. The ROM was higher in the M3 model than the M2 and M4 models. Endplate preparation created small stress differences in the healthy intervertebral discs above the ACDF site. A 1 mm embedding depth created the best balance of mechanical strength and contact area, resulting in the most favorable stability of the construct.

11.
IEEE Trans Cybern ; 52(8): 7719-7731, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35104237

RESUMO

Noise and inconsistency commonly exist in real-world information networks, due to the inherent error-prone nature of human or user privacy concerns. To date, tremendous efforts have been made to advance feature learning from networks, including the most recent graph convolutional networks (GCNs) or attention GCN, by integrating node content and topology structures. However, all existing methods consider networks as error-free sources and treat feature content in each node as independent and equally important to model node relations. Noisy node content, combined with sparse features, provides essential challenges for existing methods to be used in real-world noisy networks. In this article, we propose feature-based attention GCN (FA-GCN), a feature-attention graph convolution learning framework, to handle networks with noisy and sparse node content. To tackle noise and sparse content in each node, FA-GCN first employs a long short-term memory (LSTM) network to learn dense representation for each node feature. To model interactions between neighboring nodes, a feature-attention mechanism is introduced to allow neighboring nodes to learn and vary feature importance, with respect to their connections. By using a spectral-based graph convolution aggregation process, each node is allowed to concentrate more on the most determining neighborhood features aligned with the corresponding learning task. Experiments and validations, w.r.t. different noise levels, demonstrate that FA-GCN achieves better performance than the state-of-the-art methods in both noise-free and noisy network environments.


Assuntos
Redes Neurais de Computação , Humanos
12.
World Neurosurg ; 163: e43-e52, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35176523

RESUMO

BACKGROUND: The limitations of anterior cervical discectomy and fusion (ACDF) are related to mechanical failure of the construct after recurring subsidence and migration. In the present study, we evaluated the effect of the maximum rotation of variable angle screws on the range of motion (ROM), cage migration, and subsidence. METHODS: Five finite element models were developed from a C2-C7 cervical spine model. The first model was an intact C2-C7 spine model, and the second model was an altered C2-C7 model with C4-C6 cage insertion and a 2-level static plate. The other three models were altered C2-C7 models with the same C4-C6 cage insertion and a 2-level dynamic plate. RESULTS: The ROM of C4-C6 in the static plate model was reduced by ∼14° from the intact model but only reduced by ∼9° in the dynamic plate models. The maximum migration and subsidence at the cage-endplate interface in the dynamic plate models were lower than those in the static plate model for all moments. The von Mises stress of the C3-C4 and C6-C7 discs in the dynamic plate models was lower than that in the static plate model. CONCLUSIONS: Our results indicate that dynamic plating has promising potential (greater ROM and lower von Mises stress of discs) for stabilization in multilevel anterior cervical discectomy and fusion than static plating, although both dynamic and static plates showed lower ROM than the intact model. A lower screw rotational angle resulted in superior biomechanical performance (lower incidence of migration and subsidence) compared with a higher rotational angle in multilevel applications, regardless of loading.


Assuntos
Discotomia , Fusão Vertebral , Fenômenos Biomecânicos , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia , Discotomia/métodos , Análise de Elementos Finitos , Humanos , Amplitude de Movimento Articular , Fusão Vertebral/métodos
13.
Indian J Pathol Microbiol ; 65(1): 164-166, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35074986

RESUMO

Glomus tumor is a rare mesenchymal neoplasm arising from the modified smooth muscle cells of the glomus body. Primary crissum glomus tumor is extremely rare without any published in the literature. In this article, we report the first case of primary crissum glomus tumor in an 80-year-old man with recurrent anal pain for 8 years, increased pain for 1 year. Rectal MRI for inflammatory lesions (sinus tract). Microscopic examination showed the tumor cells were arranged in sheets and nests, surrounding blood vessels and nerve bundles. At high magnification, the neoplastic cells show regular round shape with light eosinophilic and translucent cytoplasm. The cell boundary is clear, the nucleus is round and located in the center. The stroma of the tumor shows hyaline degeneration. Immunohistochemically, the tumor cells were positive for smooth muscle actin, h-caldesmon, Calponin, synaptophysin, Collagen IV and CD34, but completely negative for HMB45, S100, EMA, desmin, CgA and CD56. The histologic features and immunohistochemical profile supported a diagnosis of primary crissum glomus tumor. The patient was asymptomatic and disease free after the procedure.


Assuntos
Canal Anal/diagnóstico por imagem , Tumor Glômico/diagnóstico por imagem , Idoso de 80 Anos ou mais , Canal Anal/patologia , Tumor Glômico/cirurgia , Humanos , Imuno-Histoquímica , Imageamento por Ressonância Magnética , Masculino , Recidiva Local de Neoplasia
14.
Sensors (Basel) ; 21(13)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202796

RESUMO

Multifunctional flexible tactile sensors could be useful to improve the control of prosthetic hands. To that end, highly stretchable liquid metal tactile sensors (LMS) were designed, manufactured via photolithography, and incorporated into the fingertips of a prosthetic hand. Three novel contributions were made with the LMS. First, individual fingertips were used to distinguish between different speeds of sliding contact with different surfaces. Second, differences in surface textures were reliably detected during sliding contact. Third, the capacity for hierarchical tactile sensor integration was demonstrated by using four LMS signals simultaneously to distinguish between ten complex multi-textured surfaces. Four different machine learning algorithms were compared for their successful classification capabilities: K-nearest neighbor (KNN), support vector machine (SVM), random forest (RF), and neural network (NN). The time-frequency features of the LMSs were extracted to train and test the machine learning algorithms. The NN generally performed the best at the speed and texture detection with a single finger and had a 99.2 ± 0.8% accuracy to distinguish between ten different multi-textured surfaces using four LMSs from four fingers simultaneously. The capability for hierarchical multi-finger tactile sensation integration could be useful to provide a higher level of intelligence for artificial hands.


Assuntos
Dedos , Tato , Algoritmos , Redes Neurais de Computação , Máquina de Vetores de Suporte
15.
Spine J ; 21(5): 874-882, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33460810

RESUMO

BACKGROUND CONTEXT: Anterior cervical discectomy and fusion (ACDF) is widely used to treat patients with spinal disorders, where the cage is a critical component to achieve satisfactory fusion results. However, it is still not clear whether a cage with screws or without screws will be the best choice for long-term fusion as the micromotion (sliding distance) and subsidence (penetration) of the cage still take place repeatedly. PURPOSE: This study aims to examine the effect of cage-screws on the biomechanical characteristics of the human spine, implanted cage, and associate hardware by comparing the micromotion and subsidence. STUDY DESIGN: A finite element (FE) analysis study. METHODS: A FE model of a C3-C5 cervical spine with ACDF was developed. The spinal segment was modeled with the removal of the anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), and discectomy was then implanted with a cage-screw system. Three models were analyzed: the first was the original spine (S1 model), the second, S2, was implanted with cages and anterior plating, and the third, S3, was implanted with a cage-screw system in addition to the anterior plate. All investigations were under 1 N•m in flexion, extension, lateral bending, and axial rotation situations. RESULTS: Finite element analysis (FEA) demonstrated that range of motion (ROM) at C3-C4 in the S2 model was significantly reduced more than that in the S3 model, while the ROM at both C4-C5 in the S3 model was reduced more than that in the S2 model in all simulations. The ROM at C3-C5 in the S1 model was reduced by over 5° in the S2 and S3 models in all loading conditions. The micromotion and subsidence at all contacts of C3-C5 in the S3 model were lower than that in the S2 model in all flexion, extension, bending, and axial simulations. The subsidence and micromotion could be seen in the barrier area of the S2 model, while they occurred near the edge of the screw in the S3 model. CONCLUSIONS: These results showed that the cage-screw and anterior plating combination has promising potential to reduce the risk of micromotion and subsidence of implanted cages in two or more level ACDFs. CLINICAL SIGNIFICANCE: The use of double segmental fixation with cage-screw anterior plating combination constructs may increase the stiffness of the construct and reduce the incidence of clinical and radiographic pseudarthrosis following multilevel ACDF, which in turn, could decrease the need for revision surgeries or supplemental posterior fixation.


Assuntos
Fusão Vertebral , Fenômenos Biomecânicos , Parafusos Ósseos , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia , Discotomia , Análise de Elementos Finitos , Humanos , Amplitude de Movimento Articular
16.
Sensors (Basel) ; 22(1)2021 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-35009754

RESUMO

Cervical disc implants are conventional surgical treatments for patients with degenerative disc disease, such as cervical myelopathy and radiculopathy. However, the surgeon still must determine the candidacy of cervical disc implants mainly from the findings of diagnostic imaging studies, which can sometimes lead to complications and implant failure. To help address these problems, a new approach was developed to enable surgeons to preview the post-operative effects of an artificial disc implant in a patient-specific fashion prior to surgery. To that end, a robotic replica of a person's spine was 3D printed, modified to include an artificial disc implant, and outfitted with a soft magnetic sensor array. The aims of this study are threefold: first, to evaluate the potential of a soft magnetic sensor array to detect the location and amplitude of applied loads; second, to use the soft magnetic sensor array in a 3D printed human spine replica to distinguish between five different robotically actuated postures; and third, to compare the efficacy of four different machine learning algorithms to classify the loads, amplitudes, and postures obtained from the first and second aims. Benchtop experiments showed that the soft magnetic sensor array was capable of precisely detecting the location and amplitude of forces, which were successfully classified by four different machine learning algorithms that were compared for their capabilities: Support Vector Machine (SVM), K-Nearest Neighbor (KNN), Random Forest (RF), and Artificial Neural Network (ANN). In particular, the RF and ANN algorithms were able to classify locations of loads applied 3.25 mm apart with 98.39% ± 1.50% and 98.05% ± 1.56% accuracies, respectively. Furthermore, the ANN had an accuracy of 94.46% ± 2.84% to classify the location that a 10 g load was applied. The artificial disc-implanted spine replica was subjected to flexion and extension by a robotic arm. Five different postures of the spine were successfully classified with 100% ± 0.0% accuracy with the ANN using the soft magnetic sensor array. All results indicated that the magnetic sensor array has promising potential to generate data prior to invasive surgeries that could be utilized to preoperatively assess the suitability of a particular intervention for specific patients and to potentially assist the postoperative care of people with cervical disc implants.


Assuntos
Disco Intervertebral , Procedimentos Cirúrgicos Robóticos , Vértebras Cervicais , Humanos , Fenômenos Magnéticos , Postura , Amplitude de Movimento Articular
17.
Int J Clin Exp Pathol ; 13(4): 818-826, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32355532

RESUMO

BACKGROUND: To investigate the clinicopathologic features, differential diagnosis, and factors associated with recurrence in patients with smooth muscle tumors of uncertain malignant potential (STUMP). METHODS: The clinical and pathologic data of STUMP patients diagnosed in Mindong Hospital of Ningde City from 2017 to 2018 were collected and slides reviewed, the high-frequency color Doppler ultrasound and pathological characteristics were observed, and the literature was reviewed. RESULTS: All the STUMP diagnoses were confirmed by slide review. The age of onset was 23-61 years (mean 42.96 years). The main clinical symptoms were leiomyoma of uterus, prolonged menstruation, and increased menstruation. Color Doppler ultrasonography showed hypoechoic uterine wall nodules. The mean follow-up time was 62.9 months (range: 13-96 months). CONCLUSIONS: Smooth muscle tumors of undetermined malignant potential (STUMP) in the uterus are one of the rare gynecologic neoplasms. Although not malignant, they should be considered as low malignant potential tumors because they occasionally recur. Six of 13 recurrent tumors recurred in the years following hysterectomy with preservation. These six recurrent tumors are the only ones that had a strong immune response to p16 and p53. In support of early observation, these markers may help predict STUMP behavior. Patients diagnosed with STUMP should be monitored over time.

18.
Sens Actuators A Phys ; 3152020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34629752

RESUMO

Design, sensing, and control of underwater gripping systems remain challenges for soft robotic manipulators. Our study investigates these critical issues by designing a shape memory alloy (SMA) actuation system for a soft robotic finger with a directly 3D-printed stretchable skin-like tactile sensor. SMA actuators were thermomechanically trained to assume a curved finger-like shape when Joule heated, and the flexible multi-layered tactile sensor was directly 3D-printed onto the surface of the fingertip. A nonlinear controller was developed to enable precise fingertip force control using feedback from the compliant tactile sensor. Underwater experiments were conducted using closed-loop force feedback from the directly 3D-printed tactile sensor with the SMA actuators, showing satisfactory force tracking ability. Furthermore, a 3D finite element model was developed to more deeply understand the shape memory thermal-fluidic-structural multi-physics simulation of the manipulator underwater. An application for human control via electromyogram (EMG) signals also demonstrated an intuitive way for a person to operate the submerged robotic finger. Together, these results suggested that the soft robotic finger could be used to carefully manipulate fragile objects underwater.

19.
Materials (Basel) ; 12(17)2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31470585

RESUMO

Growing very large size silicon ingots with low dislocation density is a critical issue for the photovoltaic industry to reduce the production cost of the high-efficiency solar cell for affordable green energy. The thermal stresses, which are produced as the result of the non-uniform temperature field, would generate dislocation in the ingot. This is a complicated thermal viscoplasticity process during the cooling process of crystal growth. A nonlinear three-dimensional transient formulation derived from the Hassen-Sumino model (HAS) was applied to predict the number of dislocation densities, which couples the macroscopic viscoplastic deformation with the microscopic dislocation dynamics. A typical cooling process during the growth of very large size (G5 size: 0.84 m × 0.84 m × 0.3 m) Si ingot is used as an example to validate the developed HAS model and the results are compared with those obtained from qualitatively critical resolved shear stress model (CRSS). The result demonstrates that this finite element model not only predicts a similar pattern of dislocation generation with the CRSS model but also anticipate the dislocation density quantity generated in the Si ingot. A modified cooling process is also employed to study the effect of the cooling process on the generation of the dislocation. It clearly shows that dislocation density is drastically decreased by modifying the cooling process. The results obtained from this model can provide valuable information for engineers to design a better cooling process for reducing the dislocation density produced in the Si ingot under the crystal growth process.

20.
ACS Appl Mater Interfaces ; 11(9): 9223-9232, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30758175

RESUMO

Inadequate oxygen and nutrient diffusion in a porous scaffold often resulted in insufficient formation of branched vasculatures, which hindered bone regeneration. In this study, interconnected porous ß-tricalcium phosphate (ß-TCP) scaffolds with different geometric designs of channels were fabricated and compared to discover the functionality of structure on facilitating nutrient diffusion for angiogenesis. In vitro fluid transportation and degradation of the scaffolds were performed. Cell infiltration, migration, and proliferation of human umbilical vein endothelial cells (HUVECs) on the scaffolds were carried out under both static and dynamic culture conditions. A computational simulation model and a series of immunofluorescent staining were implemented to understand the mechanism of cell behavior in response to different types of scaffolds. Results showed that geometry with multiple channels significantly accelerated the release of Ca2+ and increased the fluid diffusion efficiency. Moreover, multiple channels promoted HUVECs' infiltration and migration in vitro. The ex vivo implantation results showed that the channels promoted cells from the rats' calvarial bone explants to infiltrate into the implanted scaffold. Multiple channels also stimulated HUVECs' proliferation prominently at both static and dynamic culturing conditions. The expression of both cell migration-related protein α5 and angiogenesis-related protein CD31 on multiple-channeled scaffolds was upregulated compared to that on the other two types of scaffolds, implying that multiple channels reinforced cell migration and angiogenesis. All the findings suggested that the geometric design of multiple channels in the porous ß-TCP scaffold has promising potential to promote cell infiltration, migration, and further vascularization when implanted in vivo.


Assuntos
Fosfatos de Cálcio/química , Proliferação de Células , Neovascularização Fisiológica , Alicerces Teciduais/química , Adesão Celular , Movimento Celular , Células Endoteliais da Veia Umbilical Humana , Humanos , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Porosidade , Engenharia Tecidual
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