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1.
Small ; : e2310678, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38708801

RESUMO

The quality requirements of graphene depend on the applications. Some have a high tolerance for graphene quality and even require some defects, while others require graphene as perfect as possible to achieve good performance. So far, synthesis of large-area graphene films by chemical vapor deposition of carbon precursors on metal substrates, especially on Cu, remains the main way to produce high-quality graphene, which has been significantly developed in the past 15 years. However, although many prototypes are demonstrated, their performance is still more or less far from the theoretical property limit of graphene. This review focuses on how to make super graphene, namely graphene with a perfect structure and free of contaminations. More specially, this study focuses on graphene synthesis on Cu substrates. Typical defects in graphene are first discussed together with the formation mechanisms and how they are characterized normally, followed with a brief review of graphene properties and the effects of defects. Then, the synthesis progress of super graphene from the aspects of substrate, grain size, wrinkles, contamination, adlayers, and point defects are reviewed. Graphene transfer is briefly discussed as well. Finally, the challenges to make super graphene are discussed and a strategy is proposed.

2.
BMC Neurol ; 24(1): 97, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38494491

RESUMO

OBJECTIVE: To investigate the factors associated with brain frailty and the effect of brain frailty in patients with anterior circulation large artery occlusion (AC-LAO). METHODS: 1100 patients with AC-LVO consecutively admitted to the Second Hospital of Hebei Medical University, North China between June 2016 and April 2018 were retrospectively analyzed. The variables associated with brain frailty and stroke outcome were analyzed by ANOVA analysis, the Mann-Whitney U test and multiple linear regression. Based on previous research. Brain frailty score comprises 1 point each for white matter hyperintensity (WMH), old infarction lesions, and cerebral atrophy among 983 participants with baseline brain magnetic resonance imaging or computed tomography. RESULTS: Among AC-LAO participants, baseline brain frailty score ≥ 1 was common (750/983, 76.3%). Duration of hypertension > 5 years (mean difference [MD] 0.236, 95% CI 0.077, 0.395, p = 0.004), multiple vessel occlusion (MD 0.339, 95% CI 0.068, 0.611, p = 0.014) and basal ganglia infarction (MD -0.308, 95% CI -0.456, -0.160, p < 0.001) were independently associated with brain frailty score. Brain frailty score was independently associated with stroke events, and higher brain frailty scores were associated with higher rates of stroke events (p < 0.001). However, brain frailty has no independent effect on short-term outcome of ACI in AC-LAO patients. CONCLUSIONS: In AC-LAO patients, older age, duration of hypertension > 5 years, and multiple vessel occlusion influenced the brain frailty score. Brain frailty score was independently associated with the occurrence of stroke events in AC-LAO patients.


Assuntos
Isquemia Encefálica , Fragilidade , Hipertensão , Acidente Vascular Cerebral , Humanos , Estudos Retrospectivos , Fragilidade/complicações , Fragilidade/epidemiologia , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/epidemiologia , Encéfalo , Artérias , Infarto
3.
Clin Oral Investig ; 27(12): 7437-7450, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37848582

RESUMO

OBJECTIVES: This study aimed to investigate the site-specific characteristics of rat mandible periosteal cells (MPCs) and tibia periosteal cells (TPCs) to assess the potential application of periosteal cells (PCs) in bone tissue engineering (BTE). MATERIALS AND METHODS: MPCs and TPCs were isolated and characterized. The potential of proliferation, migration, osteogenesis and adipogenesis of MPCs and TPCs were evaluated by CCK-8, scratch assay, Transwell assay, alkaline phosphatase staining and activity, Alizarin Red S staining, RT‒qPCR, and Western blot (WB) assays, respectively. Then, these cells were cocultured with human umbilical vein endothelial cells (HUVECs) to investigate their angiogenic capacity, which was assessed by scratch assay, Transwell assay, Matrigel tube formation assay, RT‒qPCR, and WB assays. RESULTS: MPCs exhibited higher osteogenic potential, higher alkaline phosphatase activity, and more mineralized nodule formation, while TPCs showed a greater capability for proliferation, migration, and adipogenesis. MPCs showed higher expression of angiogenic factors, and the conditioned medium of MPCs accelerated the migration of HUVECs, while MPC- conditioned medium induced the formation of more tubular structure in HUVECs in vitro. These data suggest that compared to TPCs, MPCs exert more consequential proangiogenic effects on HUVECs. CONCLUSIONS: PCs possess skeletal site-specific differences in biological characteristics. MPCs exhibit more eminent osteogenic and angiogenic potentials, which highlights the potential application of MPCs for BTE. CLINICAL RELEVANCE: Autologous bone grafting as the main modality for maxillofacial bone defect repair has many limitations. Constituting an important cell type in bone repair and regeneration, MPCs show greater potential for application in BTE, which provides a promising treatment option for maxillofacial bone defect repair.


Assuntos
Fosfatase Alcalina , Osteogênese , Humanos , Ratos , Animais , Meios de Cultivo Condicionados/farmacologia , Meios de Cultivo Condicionados/metabolismo , Fosfatase Alcalina/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Osso e Ossos , Células Cultivadas , Diferenciação Celular
4.
Sensors (Basel) ; 22(17)2022 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-36081031

RESUMO

A brain-computer interface (BCI) translates a user's thoughts such as motor imagery (MI) into the control of external devices. However, some people, who are defined as BCI illiteracy, cannot control BCI effectively. The main characteristics of BCI illiterate subjects are low classification rates and poor repeatability. To address the problem of MI-BCI illiteracy, we propose a distribution adaptation method based on multi-kernel learning to make the distribution of features between the source domain and target domain become even closer to each other, while the divisibility of categories is maximized. Inspired by the kernel trick, we adopted a multiple-kernel-based extreme learning machine to train the labeled source-domain data to find a new high-dimensional subspace that maximizes data divisibility, and then use multiple-kernel-based maximum mean discrepancy to conduct distribution adaptation to eliminate the difference in feature distribution between domains in the new subspace. In light of the high dimension of features of MI-BCI illiteracy, random forest, which can effectively handle high-dimensional features without additional cross-validation, was employed as a classifier. The proposed method was validated on an open dataset. The experimental results show that that the method we proposed suits MI-BCI illiteracy and can reduce the inter-domain differences, resulting in a reduction in the performance degradation of both cross-subjects and cross-sessions.


Assuntos
Interfaces Cérebro-Computador , Algoritmos , Eletroencefalografia/métodos , Humanos , Imagens, Psicoterapia , Aprendizagem , Alfabetização
5.
Sensors (Basel) ; 17(5)2017 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-28467371

RESUMO

Electroencephalography (EEG)-based emotion recognition is an important element in psychiatric health diagnosis for patients. However, the underlying EEG sensor signals are always non-stationary if they are sampled from different experimental sessions or subjects. This results in the deterioration of the classification performance. Domain adaptation methods offer an effective way to reduce the discrepancy of marginal distribution. However, for EEG sensor signals, both marginal and conditional distributions may be mismatched. In addition, the existing domain adaptation strategies always require a high level of additional computation. To address this problem, a novel strategy named adaptive subspace feature matching (ASFM) is proposed in this paper in order to integrate both the marginal and conditional distributions within a unified framework (without any labeled samples from target subjects). Specifically, we develop a linear transformation function which matches the marginal distributions of the source and target subspaces without a regularization term. This significantly decreases the time complexity of our domain adaptation procedure. As a result, both marginal and conditional distribution discrepancies between the source domain and unlabeled target domain can be reduced, and logistic regression (LR) can be applied to the new source domain in order to train a classifier for use in the target domain, since the aligned source domain follows a distribution which is similar to that of the target domain. We compare our ASFM method with six typical approaches using a public EEG dataset with three affective states: positive, neutral, and negative. Both offline and online evaluations were performed. The subject-to-subject offline experimental results demonstrate that our component achieves a mean accuracy and standard deviation of 80.46% and 6.84%, respectively, as compared with a state-of-the-art method, the subspace alignment auto-encoder (SAAE), which achieves values of 77.88% and 7.33% on average, respectively. For the online analysis, the average classification accuracy and standard deviation of ASFM in the subject-to-subject evaluation for all the 15 subjects in a dataset was 75.11% and 7.65%, respectively, gaining a significant performance improvement compared to the best baseline LR which achieves 56.38% and 7.48%, respectively. The experimental results confirm the effectiveness of the proposed method relative to state-of-the-art methods. Moreover, computational efficiency of the proposed ASFM method is much better than standard domain adaptation; if the numbers of training samples and test samples are controlled within certain range, it is suitable for real-time classification. It can be concluded that ASFM is a useful and effective tool for decreasing domain discrepancy and reducing performance degradation across subjects and sessions in the field of EEG-based emotion recognition.


Assuntos
Eletroencefalografia , Algoritmos , Emoções , Humanos , Modelos Logísticos
6.
Sensors (Basel) ; 16(10)2016 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-27775640

RESUMO

Accurately measuring the oil content and salt content of crude oil is very important for both estimating oil reserves and predicting the lifetime of an oil well. There are some problems with the current methods such as high cost, low precision, and difficulties in operation. To solve these problems, we present a multifunctional sensor, which applies, respectively, conductivity method and ultrasound method to measure the contents of oil, water, and salt. Based on cross sensitivity theory, these two transducers are ideally integrated for simplifying the structure. A concentration test of ternary solutions is carried out to testify its effectiveness, and then Canonical Correlation Analysis is applied to evaluate the data. From the perspective of statistics, the sensor inputs, for instance, oil concentration, salt concentration, and temperature, are closely related to its outputs including output voltage and time of flight of ultrasound wave, which further identify the correctness of the sensing theory and the feasibility of the integrated design. Combined with reconstruction algorithms, the sensor can realize the content measurement of the solution precisely. The potential development of the proposed sensor and method in the aspect of online test for crude oil is of important reference and practical value.

7.
Neurologist ; 29(1): 4-13, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37582681

RESUMO

INTRODUCTION: We report a rare case of moyamoya disease caused by an RNF213 mutation, complicated with systemic lupus erythematosus. CASE REPORT: A 32-year-old woman experienced 4 cerebral ischemia stroke events within 6 months. The main symptom was left limb weakness with blurred vision in the right eye. Results of digital subtraction angiography conducted at another hospital were consistent with moyamoya disease. On genetic testing, we found that the patient carried 2 mutations in the moyamoya disease-related gene RNF213 (p.R4810K, p.T1727M). On the basis of the laboratory immunologic indicators, such as positive antibodies and abnormal immunoglobulin levels and imaging examinations, the patient was finally diagnosed as moyamoya disease complicated with systemic lupus erythematosus. She was treated with aspirin, butylphthalide, urinary kallidinogenase, and sodium methylprednisolone. CONCLUSIONS: This was a 32-year-old young patient diagnosed with moyamoya disease carrying RNF213 gene mutation and accompanied by lupus with cerebral ischemic event as the first occurrence. The patient's condition was complex; therefore, comprehensive analysis and in-depth consideration were needed to avoid a missed diagnosis and misdiagnosis. When the primary disease cannot be identified, genetic testing can help to clarify the diagnosis of moyamoya disease.


Assuntos
Lúpus Eritematoso Sistêmico , Doença de Moyamoya , Acidente Vascular Cerebral , Feminino , Humanos , Adulto , Doença de Moyamoya/diagnóstico , Doença de Moyamoya/diagnóstico por imagem , Mutação/genética , Infarto Cerebral/diagnóstico por imagem , Infarto Cerebral/etiologia , Lúpus Eritematoso Sistêmico/complicações , Predisposição Genética para Doença , Adenosina Trifosfatases/genética , Ubiquitina-Proteína Ligases/genética
8.
Med Biol Eng Comput ; 61(2): 357-385, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36434356

RESUMO

Networks play an important role in studying structure or functional connection of various brain areas, and explaining mechanism of emotion. However, there is a lack of comprehensive analysis among different construction methods nowadays. Therefore, this paper studies the impact of different emotions on connection of functional brain networks (FBNs) based on electroencephalogram (EEG). Firstly, we defined electrode node as brain area of vicinity of electrode to construct 32-node small-scale FBN. Pearson correlation coefficient (PCC) was used to construct correlation-based FBNs. Phase locking value (PLV) and phase synchronization index (PSI) were utilized to construct synchrony-based FBNs. Next, global properties and effects of emotion of different networks were compared. The difference of synchrony-based FBN concentrates in alpha band, and the number of differences is less than that of correlation-based FBN. Node properties of different small-scale FBNs have significant differences, offering a new basis for feature extraction of recognition regions in emotional FBNs. Later, we made partition of electrode nodes and 10 new brain areas were defined as regional nodes to construct 10-node large-scale FBN. Results show the impact of emotion on network clusters on the right forehead, and high valence enhances information processing efficiency of FBN by promoting connections in brain areas.


Assuntos
Encéfalo , Emoções , Eletroencefalografia/métodos , Mapeamento Encefálico/métodos , Eletrodos
9.
IEEE J Biomed Health Inform ; 27(12): 5722-5733, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37695963

RESUMO

OBJECTIVE: The latest development in low-cost single-channel Electroencephalography (EEG) devices is gaining widespread attention because it reduces hardware complexity. Discrete wavelet transform (DWT) has been a popular solution to eliminate the blink artifacts in EEG signals. However, the existing DWT-based methods share the same wavelet function among subjects, which ignores the individual difference. To remedy this deficiency, this article proposes a novel approach to eliminate the blink artifacts in single-channel EEG signals. METHODS: Firstly, the forward-backward low-pass filter (FBLPF) and a fixed-length window are used to detect blink artifact intervals. Secondly, the adaptive bi-orthogonal wavelet (ABOW) is constructed based on the most representative blink signal. Thirdly, these detected signals are filtered by ABOW-DWT. The DWT's decomposition depth is automatically chosen by a similarity-based method. RESULTS: Compared to eight state-of-the-art methods, experiments on semi-simulated and real EEG signals demonstrate the proposed method's superiority in removing the blink artifacts with less neural information loss. SIGNIFICANCE: To filter the blink artifacts in single-channel EEG signals, the innovative idea of constructing an adaptive wavelet function based on the signal characteristics rather than using the conventional wavelet is proposed for the first time.


Assuntos
Algoritmos , Artefatos , Humanos , Piscadela , Análise de Ondaletas , Eletroencefalografia/métodos , Processamento de Sinais Assistido por Computador
10.
Comput Biol Med ; 163: 107235, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37442010

RESUMO

It is impractical to collect sufficient and well-labeled EEG data in Brain-computer interface because of the time-consuming data acquisition and costly annotation. Conventional classification methods reusing EEG data from different subjects and time periods (across domains) significantly decrease the classification accuracy of motor imagery. In this paper, we propose a deep domain adaptation framework with correlation alignment (DDAF-CORAL) to solve the problem of distribution divergence for motor imagery classification across domains. Specifically, a two-stage framework is adopted to extract deep features for raw EEG data. The distribution divergence caused by subjected-related and time-related variations is further minimized by aligning the covariance of the source and target EEG feature distributions. Finally, the classification loss and adaptation loss are optimized simultaneously to achieve sufficient discriminative classification performance and low feature distribution divergence. Extensive experiments on three EEG datasets demonstrate that our proposed method can effectively reduce the distribution divergence between the source and target EEG data. The results show that our proposed method delivers outperformance (an average classification accuracy of 92.9% for within-session, an average kappa value of 0.761 for cross-session, and an average classification accuracy of 83.3% for cross-subject) in two-class classification tasks compared to other state-of-the-art methods.


Assuntos
Interfaces Cérebro-Computador , Eletroencefalografia , Eletroencefalografia/métodos , Algoritmos , Adaptação Fisiológica , Imaginação
11.
Quant Imaging Med Surg ; 13(5): 2941-2952, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37179948

RESUMO

Background: In-stent restenosis is a crucial problem after carotid artery stenting, but the exact predictors of in-stent restenosis remain unclear. We aimed to evaluate the effect of cerebral collateral circulation on in-stent restenosis after carotid artery stenting and to establish a clinical prediction model for in-stent restenosis. Methods: This retrospective case-control study enrolled 296 patients with severe carotid artery stenosis of C1 segment (≥70%) who underwent stent therapy from June 2015 to December 2018. Based on follow-up data, the patients were divided into the in-stent restenosis and no in-stent restenosis groups. The collateral circulation of the brain was graded according to the criteria of the American Society for Interventional and Therapy Neuroradiology/Society for Interventional Radiology (ASITN/SIR). Clinical data were collected, such as age, sex, traditional vascular risk factors, blood cell count, high-sensitivity C-reactive protein, uric acid, stenosis degree before stenting and residual stenosis rate, and medication after stenting. Binary logistic regression analysis was performed to identify potential predictors of in-stent restenosis, and a clinical prediction model for in-stent restenosis after carotid artery stenting was established. Results: Binary logistic regression analysis showed that poor collateral circulation was an independent predictor of in-stent restenosis (P=0.003). We also found that a 1% increase in residual stenosis rate was associated with a 9% increase in the risk of in-stent restenosis (P=0.02). Ischemic stroke history (P=0.03), family history of ischemic stroke (P<0.001), in-stent restenosis history (P<0.001), and nonstandard medication after stenting (P=0.04) were predictors of in-stent restenosis. The risk of in-stent restenosis was lowest when the residual stenosis rate was 12.5% after carotid artery stenting. Furthermore, we used some significant parameters to construct a binary logistic regression prediction model for in-stent restenosis after carotid artery stenting in the form of a nomogram. Conclusions: Collateral circulation is an independent predictor of in-stent restenosis after successful carotid artery stenting, and the residual stenosis rate tends to be below 12.5% to reduce restenosis risk. The standard medication should be strictly carried out for patients after stenting to prevent in-stent restenosis.

12.
Neuroscience ; 506: 14-28, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36156290

RESUMO

Neuronal necroptosis and apoptosis are the most important pathways for programmed cell death after brain ischaemic stroke. Although apoptosis signalling pathways have been extensively studied, molecular mechanisms underlying necroptosis remain unclear. In this study, we found that receptor-interacting protein 3 (RIP3) deficiency reduced cerebral infarction volume, neurological deficits, and neuronal ultrastructural damage in a mouse model of brain ischaemic stroke by inhibiting programmed cell death. RIP3 deficiency inhibited the activation of both calmodulin-dependent kinase II (CaMKII) and proline-rich tyrosine kinase 2 (Pyk2) cascade, decreased the expression of classic necroptotic and apoptotic proteins, and ultimately decreased neuronal necroptosis and apoptosis. We further confirmed that RIP3 deficiency inhibited the decrease of mitochondrial membrane potential, the increase of calcium influx and reactive oxygen species (ROS) production. In addition, compared with WT primary cortical neurons, the decreased expression of CaMKII and Pyk2 was further verified in a Ripk3-/- primary cortical neurons underlying oxygen and glucose deprivation/reoxygenation (OGD/R) model. In conclusion, we first identified that the RIP3/CaMKII/Pyk2 pathway is involved in programmed cell death after brain ischaemic stroke, which suggests it is a promising therapeutic target in ischaemia-induced neuronal injury.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Animais , Camundongos , Quinase 2 de Adesão Focal , Calmodulina , Encéfalo , Apoptose
13.
J Healthc Eng ; 2021: 9376662, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34413970

RESUMO

Respiratory diseases including apnea are often accompanied by abnormal respiratory depth, frequency, and rhythm. If different abnormal respiratory patterns can be detected and recorded, with their depth, frequency, and rhythm analyzed, the detection and diagnosis of respiratory diseases can be achieved. High-frequency millimeter-wave radar (76-81 GHz) has low environmental impact, high accuracy, and small volume, which is more suitable for respiratory signal detection and recognition compared with other contact equipment. In this paper, the experimental platform of frequency-modulated continuous wave (FMCW) radar was built at first, realizing the noncontact measurement of vital signs. Secondly, the energy intensity and threshold of respiration signal during each period were calculated by using the rectangular window, and the accurate judgment of apnea was realized via numerical comparison. Thirdly, the features of respiratory and heart rate signals, the number of peaks and valleys, the difference between peaks and valleys, the average and the standard deviation of normalized short-term energy, and the average and the standard deviation and the minimum of instantaneous frequency, were extracted and analyzed. Finally, support vector machine (SVM) and K-nearest neighbor (KNN) were used to classify the extracted features, and the accuracy was 98.25% and 88.75%, respectively. The classification and recognition of respiratory patterns have been successfully realized.


Assuntos
Radar , Processamento de Sinais Assistido por Computador , Algoritmos , Humanos , Taxa Respiratória , Tecnologia , Sinais Vitais
14.
Front Neurol ; 12: 749599, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34925213

RESUMO

Objectives: Patients with anterior circulation large vessel occlusion are at high risk of acute ischemic stroke, which could be disabling or fatal. In this study, we applied machine learning to develop and validate two prediction models for acute ischemic stroke (Model 1) and severity of neurological impairment (Model 2), both caused by anterior circulation large vessel occlusion (AC-LVO), based on medical history and neuroimaging data of patients on admission. Methods: A total of 1,100 patients with AC- LVO from the Second Hospital of Hebei Medical University in North China were enrolled, of which 713 patients presented with acute ischemic stroke (AIS) related to AC- LVO and 387 presented with the non-acute ischemic cerebrovascular event. Among patients with the non-acute ischemic cerebrovascular events, 173 with prior stroke or TIA were excluded. Finally, 927 patients with AC-LVO were entered into the derivation cohort. In the external validation cohort, 150 patients with AC-LVO from the Hebei Province People's Hospital, including 99 patients with AIS related to AC- LVO and 51 asymptomatic AC-LVO patients, were retrospectively reviewed. We developed four machine learning models [logistic regression (LR), regularized LR (RLR), support vector machine (SVM), and random forest (RF)], whose performance was internally validated using 5-fold cross-validation. The performance of each machine learning model for the area under the receiver operating characteristic curve (ROC-AUC) was compared and the variables of each algorithm were ranked. Results: In model 1, among the included patients with AC-LVO, 713 (76.9%) and 99 (66%) suffered an acute ischemic stroke in the derivation and external validation cohorts, respectively. The ROC-AUC of LR, RLR and SVM were significantly higher than that of the RF in the external validation cohorts [0.66 (95% CI 0.57-0.74) for LR, 0.66 (95% CI 0.57-0.74) for RLR, 0.55 (95% CI 0.45-0.64) for RF and 0.67 (95% CI 0.58-0.76) for SVM]. In model 2, 254 (53.9%) and 31 (37.8%) patients suffered disabling ischemic stroke in the derivation and external validation cohorts, respectively. There was no difference in AUC among the four machine learning algorithms in the external validation cohorts. Conclusions: Machine learning methods with multiple clinical variables have the ability to predict acute ischemic stroke and the severity of neurological impairment in patients with AC-LVO.

15.
Sci Rep ; 10(1): 3442, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32103113

RESUMO

Anterior circulation large artery occlusion (AC-LAO) related acute ischemic stroke (AIS) is particularly common in clinics in China. We retrospectively analyzed 787 consecutively hospitalized AIS patients with AC-LAO in Hebei Province, China. AC-LAO was defined as a complete occlusion of at least one intracranial internal carotid artery (ICA) or middle cerebral artery (MCA) based on computed tomography or magnetic resonance angiography. Among eight subtypes of AC-LAO, unilateral MCA occlusion is the most common one (49.8%, n = 392), while bilateral ICA/unilateral MCA occlusion is the least (0.3%, n = 2). Compared with unilateral MCA and unilateral ICA occlusion, patients with tandem ICA/MCA and bilateral ICA/MCA occlusion had poor outcomes after suffering AIS. Age (OR 1.022; 95%CI, 1.007 to 1.036) was an independent risk factor for single artery progressed to multiple artery occlusion, while ApoA1 (OR 0.453; 95% CI, 0.235 to 0.953) was a protective factor. Patients with unilateral MCA occlusion were prone to artery-to-artery embolism infarction subtype, unilateral ICA occlusion group were the most vulnerable to hypoperfusion/impaired emboli clearance subtype. Our results suggested various AC-LAO subtypes have different clinical characteristics and prognosis and were prone to different subtypes of infarction. Customized preventive measures based on AC-LAO subtypes may be more targeted preventions of stroke recurrences for AIS patients and could improve their prognoses.


Assuntos
Doenças das Artérias Carótidas/patologia , Infarto da Artéria Cerebral Média/patologia , Acidente Vascular Cerebral/diagnóstico , Idoso , Doenças das Artérias Carótidas/complicações , Artéria Carótida Interna/diagnóstico por imagem , Feminino , Humanos , Infarto da Artéria Cerebral Média/complicações , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Estudos Retrospectivos , Fatores de Risco , Índice de Gravidade de Doença , Acidente Vascular Cerebral/etiologia , Tomografia Computadorizada por Raios X
16.
Comput Assist Surg (Abingdon) ; 24(sup1): 160-166, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30689430

RESUMO

Near infrared spectroscopy is the promising and noninvasive technique that can be used to detect the brain functional activation by monitoring the concentration alternations in the haemodynamic concentration. The acquired NIRS signals are commonly contaminated by physiological interference caused by breathing and cardiac contraction. Though the adaptive filtering method with least mean squares algorithm or recursive least squares algorithm based on multidistance probe configuration could improve the quality of evoked brain activity response, both methods can only remove the physiological interference occurred in superficial layers of the head tissue. To overcome the shortcoming, we combined the recursive least squares adaptive filtering method with the least squares support vector machine to suppress physiological interference both in the superficial layers and deeper layers of the head tissue. The quantified results based on performance measures suggest that the estimation performances of the proposed method for the evoked haemodynamic changes are better than the traditional recursive least squares method.


Assuntos
Encéfalo/fisiologia , Análise dos Mínimos Quadrados , Espectroscopia de Luz Próxima ao Infravermelho , Máquina de Vetores de Suporte , Algoritmos , Hemoglobinas/metabolismo , Humanos , Método de Monte Carlo
17.
Comput Assist Surg (Abingdon) ; 24(sup1): 144-150, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30676092

RESUMO

Continuous wave near-infrared spectroscopy (CW-NIRS) can be used to measure cerebral activity because it is noninvasive, simple and portable. However, the performance of the continuous wave near-infrared spectroscopy is distorted by the presence of extracerebral layer. Change of optical parameters in gray matter layer will then be inappropriately converted into the brain activity response. In the current study, a five-layer structure model constitute of scalp, skull, cerebrospinal fluid, gray matter and white matter, have been applied to fabricate human brain tissue. The phantom is made by the mixture of the Intralipid, India ink and agar. The optical parameters of gray matter layer can be flexibly adjusted to simulate the change of the deep brain tissue. The near infrared optical measurement system was designed to detect the changes in the absorption coefficients of the gray matter and quantitative analyze the influence of the extracerebral layers. Monte Carlo technique for the equivalent multi-layered brain tissue models is then performed to compensate partial volume effect introduced by the extracerebral layers. The results of the experiments suggested that the extracerebral layers influence the measurement and the influence of the extracerebral layers can be suppressed by correcting partial volume effect using Monte Carlo simulations.


Assuntos
Encéfalo , Modelos Anatômicos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Humanos , Método de Monte Carlo
18.
Comput Assist Surg (Abingdon) ; 24(sup1): 167-173, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30620225

RESUMO

Surface EEG (Electroencephalography) signal is vulnerable to interference due to its characteristics and sampling methods. So it is of great importance to evaluate the collected EEG signal prior to use. Traditional methods usually use the impedance between skin and electrode to estimate the quality of the EEG signal, which has shortcomings such as monotonous features, high false positive rates, and poor real-time capability. Aiming at addressing these issues, this paper presents a novel model of EEG quality assessment based on Fuzzy Comprehensive Evaluation method. The developed model employs amplitude, power frequency ratio, and alpha band PSD (Power Spectral Density) ratio of resting EEG signal as evaluation factors, and performs a quantitative assessment of the signal quality. Experiments show that the proposed model can significantly determine the EEG signal quality. In addition, the model is simple in implementation with low computational complexity, and is able to present the EEG quality evaluation results in real time. Before the formal measurement, collecting short-term resting EEG data, and evaluating the EEG signal quality and current signal acquisition environment using the model, the collection efficiency of qualified EEG signals can be greatly improved.


Assuntos
Eletroencefalografia , Lógica Fuzzy , Modelos Teóricos , Humanos , Processamento de Sinais Assistido por Computador
19.
Pharmazie ; 63(6): 446-52, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18604988

RESUMO

A novel polymeric micellar formulation of paclitaxel (PTX) with Pluronic/poly(caprolactone) (P105/ PCL50) has been developed with the purpose of improving in vitro release and in vivo circulating time of PTX in comparison to the current Taxol injection. This study was designed to investigate the preparation, in vitro release, in vivo pharmacokinetics and tissue distribution of the PTX-loaded, biodegradable, polymeric, P105/PCL50 micelle system. The drug-loaded micelles were prepared by dialysis using the hydrophobic drug, PTX, and the nonionic surfactant Pluronic P105 modified with a low molecular weight PCL. The results of dynamic light scattering (DLS) experiment indicated that the PTX-loaded micelles had a mean size of approximately 150 nm with narrow size distribution (polydispersity index < 0.3). The in vitro release study showed that the release of PTX from the micelles exhibited a sustained release behavior. A similar phenomenon was also observed in a pharmacokinetic assessment in rats, in which t1/2 beta and AUC of the PTX micelle formulation were 4.0 and 2.2-fold higher than that of Taxol injection. The biodistribution study in mice showed that the PTX micelle formulation not only decreased drug uptake by the liver, but also prolonged drug retention in the blood, and increased the distribution of drug in kidney, spleen, ovaries and uterus. These results suggested that the P105/ PCL50 polymeric micelles may efficiently load, protect and retain PTX in both in vitro and in vivo environments, and could be a useful drug carrier for i.v. administration of PTX.


Assuntos
Antineoplásicos Fitogênicos/farmacocinética , Paclitaxel/farmacocinética , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Área Sob a Curva , Fenômenos Químicos , Físico-Química , Cromatografia Líquida de Alta Pressão , Composição de Medicamentos , Feminino , Indicadores e Reagentes , Camundongos , Micelas , Modelos Estatísticos , Paclitaxel/administração & dosagem , Poloxâmero , Poliésteres , Polímeros , Ratos , Ratos Sprague-Dawley , Espectrofotometria Ultravioleta , Distribuição Tecidual
20.
Technol Health Care ; 26(S1): 327-335, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29758967

RESUMO

Emotion recognition based on EEG signals is a critical component in Human-Machine collaborative environments and psychiatric health diagnoses. However, EEG patterns have been found to vary across subjects due to user fatigue, different electrode placements, and varying impedances, etc. This problem renders the performance of EEG-based emotion recognition highly specific to subjects, requiring time-consuming individual calibration sessions to adapt an emotion recognition system to new subjects. Recently, domain adaptation (DA) strategies have achieved a great deal success in dealing with inter-subject adaptation. However, most of them can only adapt one subject to another subject, which limits their applicability in real-world scenarios. To alleviate this issue, a novel unsupervised DA strategy called Multi-Subject Subspace Alignment (MSSA) is proposed in this paper, which takes advantage of subspace alignment solution and multi-subject information in a unified framework to build personalized models without user-specific labeled data. Experiments on a public EEG dataset known as SEED verify the effectiveness and superiority of MSSA over other state of the art methods for dealing with multi-subject scenarios.


Assuntos
Algoritmos , Eletroencefalografia/métodos , Emoções/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Entropia , Humanos , Fatores de Tempo
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