Ideas and methods of in vitro model establishment for cell microenvironment in COPD / 中国药理学通报

Chronic obstructive pulmonary disease ( COPD ) major chronic disease threatening public health with complex pathological mechanisms. The change of the cell microenvironment of the lung is an important part of the pathophysiology of COPD. Cell culture technology is an important method to investigate the pathological mechanism of COPD and evaluate the pharmacological effect of medicine. Here we introduce the composition of the cell microenvironment of the lung, the change of the cell microenvironment in the pathological process of COPD, and summarize the application of in vitro model mimics cell microenvironment of COPD in the study of mechanism. In addition, we aim to put forward the ideas of the in vitro model establishment of cell microenvironment of COPD.

Effect of brain-computer interface based on visual, auditory and motor feedback combined with transcranial direct current stimulation on upper limb function in stroke patients / 中国康复理论与实践

ObjectiveTo explore the effect of brain-computer interface (BCI) based on visual, auditory and motor feedback combined with transcranial direct current stimulation (tDCS) on upper limb function in stroke patients. MethodsFrom March to October, 2023, 45 stroke inpatients in Xuzhou Rehabilitation Hospital and Xuzhou Central Hospital were divided into BCI group (n = 15), tDCS group (n = 15) and combined group (n = 15) randomly. All the groups received routine rehabilitation, while BCI group received BCI training, tDCS group received tDCS, while the combined group received tDCS and followed by BCI training immediately, for four weeks. They were assessed with Fugl-Meyer Assessment-Upper Extremities (FMA-UE), Action Research Arm Test (ARAT), modified Barthel Index (MBI) and delta-alpha ratio (DAR) and power ratio index (PRI) of electroencephalogram before and after treatment. ResultsThe scores of FMA-UE, ARAT and MBI increased in all the groups after treatment (|t| > 5.350, P < 0.001), and all these indexes were the best in the combined group (F > 3.366, P < 0.05); while DAR and PRI decreased in all the groups (|t| > 2.208 , P < 0.05), they were the best in the combined group (F > 5.224, P < 0.01). ConclusionBCI based on visual, auditory and motor feedback combined with tDCS can further improve the motor function of upper limbs and the activities of daily living of stroke patients.

Complexos polieletrólitos de quitosana e xantana carregados com ativos naturais e sintéticos: estudo físico/químico e microbiológico para aplicação de drug delivery / Polyelectrolyte complexes of chitosan and xanthan loaded with natural and synthetic actives: physicochemical and microbiological study for drug delivery application

A eficácia dos implantes osseointegrados é amplamente reconhecida na literatura científica. Contudo, infiltrações bacterianas na junção implante-pilar podem desencadear inflamação nos tecidos circundantes, contribuindo para a evolução de condições mais sérias, como a peri-implantite. O objetivo desse estudo foi produzir complexos polieletrólitos (PECs) de quitosana (Q) e xantana (X) em forma de membranas, carregá-las com ativos naturais e sintéticos antimicrobianos, caracterizálas estruturalmente e avaliá-las frente a degradação enzimática, cinética de liberação e ações antimicrobianas com finalidade de aplicação para drug delivery. Membranas de QX a 1% (m/v) foram produzidas em três proporções, totalizando doze grupos experimentais: QX (1:1); QX (1:2), QX (2:1), QX-P (com própolis) (1:1); QX-P (1:2); QX-P (2:1); QX-C (com canela) (1:1); QX-C (1:2); QX-C (2:1) e CLX (com clorexidina 0,2%) (1:1); CLX (1:2); CLX (2:1). Para os estudos de caracterização foram feitas análises da espessura em estado seco; análises morfológicas superficial e transversal em Microscopia Eletrônica de Varredura (MEV); análise estrutural de espectroscopia de infravermelho por transformada de Fourier (FTIR); análise de degradação por perda de massa sob ação da enzima lisozima; e análise da cinética de liberação dos ativos em saliva artificial. Para os testes microbiológicos, análises de verificação de halo de inibição e ação antibiofilme foram feitas contra cepas de Staphylococcus aureus (S. aureus) e Escherichia coli (E. coli). Os resultados demonstraram que a espessura das membranas variou conforme a proporção, sendo que o grupo QX (1:2) apresentou a maior média de 1,022 mm ± 0,2, seguida respectivamente do QX (1:1) com 0,641 mm ± 0,1 e QX (2:1) com 0,249 mm ± 0,1. Nas imagens de MEV é possível observar uma maior presença de fibras, rugosidade e porosidade nos grupos QX (1:2) e QX (1:1) respectivamente, e, no QX (2:1) uma superfície mais lisa, uniforme e fina. No FTIR foram confirmados os picos característicos dos materiais isoladamente, além de observar as ligações iônicas que ocorreram para formação dos PECs. Na análise de degradação, os grupos com ativos naturais adicionados tiveram melhores taxas de sobrevida do que os grupos QX. No teste de liberação, os grupos QX-P tiveram uma cinética mais lenta que os QX-C, cuja liberação acumulada de 100% foi feita em 24 h. Já nos testes do halo inibitório, somente os grupos CLX tiveram ação sobre as duas cepas, e os QX-P tiveram sobre S. aureus. Nas análises antibiofilme, os grupos CLX apresentaram as maiores taxas de redução metabólica nas duas cepas (± 79%); os grupos QX-P apresentaram taxas de redução similares em ambas as cepas, porém com percentual um pouco maior para E. coli (60- 80%) e os grupos QX-C tiveram grande discrepância entre as duas cepas: de 35 a 70% para S. aureus e 14 a 19% para E. coli. Pode-se concluir que, frente as análises feitas, o comportamento do material foi afetado diretamente pelos ativos adicionados a matriz polimérica. As proporções de Q ou X afetaram somente a espessura final. Quanto a aplicação proposta de drug delivery, os dispositivos apresentaram grande potencial, principalmente os grupos CLX e QX-P. (AU)

The effectiveness of osseointegrated implants is widely recognized in scientific literature. However, bacterial infiltrations at the implant-abutment interface may trigger inflammation in surrounding tissues, contributing to the development of more serious conditions, such as peri-implantitis. The aim of this study was to produce chitosan (Q) and xanthan (X) polyelectrolyte complexes (PECs) in the form of membranes, load and evaluate them for enzymatic degradation, release kinetics, and antimicrobial actions for drug delivery applications. QX membranes at 1% (w/v) were produced in three proportions, totaling twelve experimental groups: QX (1:1), QX (1:2), QX (2:1), QX-P (with propolis) (1:1), QX-P (1:2), QX-P (2:1), QX-C (with cinnamon) (1:1), QX-C (1:2), QX-C (2:1), and CLX (with 0.2% chlorhexidine) (1:1), CLX (1:2), CLX (2:1). Characterization studies included analyses of dry state thickness, surface and crosssectional morphology using Scanning Electron Microscopy (SEM), structural analysis by Fourier Transform Infrared (FTIR) spectroscopy, mass loss degradation analysis under lysozyme action, and active release kinetics analysis in artificial saliva. Microbiological tests included verification analyses of inhibition halos and antibiofilm action against strains of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Results showed that membrane thickness varied according to proportion, with group QX (1:2) presenting the highest average of 1.022 mm ± 0.2, followed by QX (1:1) with 0.641 mm ± 0.1, and QX (2:1) with 0.249 mm ± 0.1. SEM images showed greater presence of fibers, roughness, and porosity in groups QX (1:2) and QX (1:1) respectively, while QX (2:1) exhibited a smoother, more uniform, and thinner surface. FTIR confirmed characteristic peaks of the materials individually, besides showing ionic bonds formed for PECs. Degradation analysis revealed that groups with added natural actives had better survival rates than QX groups. In release tests, QX-P groups exhibited slower kinetics than QX-C, with 100% cumulative release achieved in 24 h. inhibitory halo tests, only CLX groups exhibited action against both strains, while QX-P acted against S. aureus. Antibiofilm analyses showed CLX groups with the highest metabolic reduction rates in both strains (± 79%); QX-P groups showed similar reduction rates in both strains, slightly higher for E. coli (60-80%), and QX-C groups had a significant discrepancy between strains: 35-70% for S. aureus and 14-19% for E. coli. In conclusion, material behavior was directly affected by added actives to the polymeric matrix. Proportions of Q or X only affected final thickness. Regarding proposed drug delivery applications, the devices showed great potential, especially CLX and QX-P groups.(AU)

Methods for Improving Brain-Computer Interface: Using A Brain-Directed Adjuvant and A Second-Generation Artificial Intelligence System to Enhance Information Streaming and Effectiveness of Stimuli

Background: The brain-computer interface (BCI) is gaining much attention to treat neurological disorders and improve brain-dependent functions. Significant achievements over the last decade have focused on engineering and computation technology to enhance the recording of signals and the generation of output stimuli. Nevertheless, many challenges remain for the translation of BCIs to clinical applications. Methods: We review the relevant data on the four significant gaps in enhancing BCI's clinical implementation and effectiveness. Results: The paper describes three methods to bridge the current gaps in the clinical application of BCI. The first is using a brain-directed adjuvant with a high safety profile, which can improve the accuracy of brain signaling, summing of information, and production of stimuli. The second is implementing a second-generation artificial intelligence system that is outcome-oriented for improving data streaming, recording individualized brain-variability patterns into the algorithm, and improving closed-loop learning at the level of the brain and with the target organ. The system overcomes the compensatory mechanisms that underlie the loss of stimuli' effectiveness for ensuring sustainable effects. Finally, we use inherent brain parameters relevant to consciousness and brain function to bridge some of the described gaps. Conclusions: Combined with the currently developed techniques for enhancing effectiveness and ensuring a sustainable response, these methods can potentially improve the clinical outcome of BCI techniques.

Evaluation of hydrophilic surface osseointegration in low-density bone: Preclinical study in rabbits

Abstract The aim of this study was to evaluate the osseointegration of a hydrophilic surface (blasting + acid etching + immersion in isotonic solution) in comparison with that of a control surface (blasting + acid etching) using an experimental model of low-density bone. To perform the study, 24 rabbits were submitted to the installation of 4 implants in the iliac bone bilaterally: 2 implants with a control surface and 2 implants with a hydrophilic surface. The rabbits were euthanized at 2, 4, and 8 weeks after implant installation. After euthanasia, one implant from each surface was used to perform the removal torque analysis, and the other implant was used for the execution of non-decalcified histological sections and evaluation of the bone implant contact (% BIC) as well as the fraction of bone tissue area between the implant threads (% BBT). The implants with a hydrophilic surface presented higher %BIC (42.92 ± 2.85% vs. 29.49 ± 10.27%) and % BBT (34.32 ± 8.52% vs. 23.20 ± 6.75%) (p < 0.05) in the 2-week period. Furthermore, the hydrophilic surface presented higher removal torque in the 8-week period (76.13 ± 16.00 Ncm2 vs. 52.77 ± 13.49 Ncm2) (p<0.05). Implants with a hydrophilic surface exhibited acceleration in the process of osseointegration, culminating in greater secondary stability in low-density bone than in implants with a control surface.

Resumo O objetivo deste estudo foi avaliar a osseointegração de uma superfície hidrofílica (jateamento + ataque ácido + imersão em solução isotônica) em comparação com uma superfície controle (jateamento + ataque ácido) usando um modelo experimental de osso de baixa densidade. Para realizar o estudo, 24 coelhos foram submetidos a instalação de 4 implantes bilateralmente no osso ilíaco: 2 implantes com superfície controle e 2 implantes com superfície hidrofílica. Os coelhos foram eutanasiados com 2, 4 e 8 semanas após a instalação dos implantes. Após a eutanásia, um implante de cada superfície foi usado para avaliar o torque de remoção, e o outro implante foi utilizado para execução de cortes histológicos não descalcificados e avaliação de contato osso implante (% BIC) bem como a fração da área tecido ósseo entre as roscas do implante (% BBT). Os implantes com superfície hidrofílica apresentaram maior %BIC (42.92 ± 2.85% vs. 29.49 ± 10.27%) e % BBT (34.32 ± 8.52% vs. 23.20 ± 6.75%) (p < 0.05) no período de 2 semanas. Além disso, a superfície hidrofílica apresentou maior torque de remoção no período de 8 semana (76.13 ± 16.00 Ncm2 vs. 52.77 ± 13.49 Ncm2) (p<0.05). Implantes com a superfície hidrofílica apresentaram aceleração no processo de osseointregração, culminando em melhor estabilidade secundária no osso de baixa densidade em relação a implantes com superfície controle.

Interface entre trabalho e família no período da pandemia da COVID-19: percepção de teletrabalhadores e gestores de Recursos Humanos / The interface between work and family in the period of the COVID-19 pandemic: perception of teleworkers and Human Resources managers / Interfaz entre trabajo y familia en el período de la pandemia de COVID-19: percepción de teletrabajadores y gestores de Recursos Humanos

INTRODUÇÃO: Família e trabalho configuram-se como domínios que auxiliam na compreensão do comportamento do indivíduo de forma coletiva e individual. A pandemia da COVID-19 e a adesão ao home office tornaram relevante pensar nas interfaces estabelecidas entre trabalho-família e, também, no papel dos gestores organizacionais nessa relação. OBJETIVO: Identificar como teletrabalhadores e profissionais de gestão de pessoas/saúde ocupacional (GP/SO) têm percebido as interfaces entre trabalho-família em tempos de pandemia da COVID-19. METODOLOGIA: O trabalho foi composto por dois estudos complementares: uma revisão de literatura e uma pesquisa empírica sobre a percepção de profissionais de gestão de pessoas/saúde ocupacional. Para a revisão, buscas nas bases eletrônicas Scielo, Pepsic e Lilacs foram realizadas, sendo selecionados artigos científicos que abordassem o equilíbrio entre trabalho e família durante a pandemia da Covid-19. Para a pesquisa empírica, participaram do estudo 38 profissionais de GP/SO, que responderam a um questionário online. As respostas foram analisadas por meio da análise de conteúdo temática. RESULTADOS: Identificou-se na visão dos teletrabalhadores, mudanças na dinâmica trabalho-família, dificuldades financeiras, necessidade de usar novas tecnologias para a realizar o trabalho, prejuízos à saúde mental, questões relacionadas a gênero e possíveis estratégias de enfrentamento. Na visão da GP/SO, os trabalhadores tiveram dificuldade em conciliar trabalho-família. A falta de equipamentos e ambiente adequados influenciaram de forma negativa na produtividade. CONCLUSÃO: Acredita-se que o cenário pandêmico, associado ao aumento da jornada de trabalho e à cobrança excessiva por produtividade, tenha elevado o nível de tensão/estresse entre os indivíduos, gerando desequilíbrio entre as esferas familiar e ocupacional.

INTRODUCTION: Family and work are configured as domains that help in understanding the individual's behavior collectively and individually. The COVID-19 pandemic and remote work adherence made it relevant to think about the interfaces established between family work and also on the role of organizational managers in this relationship OBJECTIVE: To identify how teleworkers and people management/ occupational health professionals (PM/OHP) have perceived the interfaces between work and family during the COVID-19 pandemic. METHODOLOGY: The present work consisted of two complementary studies: a literature review and one empirical research about the perception of PM/OHP regarding the same phenomenon. For the review, searches were performed in the Scielo, Pepsic, and Lilacs electronic databases, and scientific articles that addressed the balance between work and family during the COVID-19 pandemic. For the empirical research, 38 PM/OHP participated in the study, and answered an online questionnaire. The answers were analyzed using thematic content analysis. RESULTS: It was identified in the view of teleworkers, changes in work-family dynamics, financial difficulties, the need to use new technologies to perform work, damage to mental health, gender-related issues and possible coping strategies. In the PM/OHP view, workers had difficulty reconciling family and work. The lack of adequate equipment and environment negatively influenced productivity. CONCLUSION: It's believed that the pandemic scenario, associated with the increase in working hours and excessive demands for productivity, has increased the level of tension and stress among individuals, generating an imbalance in the family and occupational spheres.

INTRODUCCIÓN: La familia y el trabajo se configuran como dominios que ayudan a comprender el comportamiento del individuo de manera colectiva e individual. La pandemia de COVID-19 y la adhesión al home office hicieron relevante pensar en las interfaces establecidas entre el trabajo familiar y también en el papel de los gerentes organizacionales en esta relación OBJETIVO: Identificar cómo los teletrabajadores y los profesionales de la gestión de personas/salud ocupacional (PGP/SO) han percibido las interfaces entre el trabajo y la familia durante la pandemia de COVID-19. METODOLOGÍA: El presente trabajo consistió en dos estudios complementarios: una revisión bibliográfica y una investigación empírica sobre la percepción de PM/OHP respecto al mismo fenómeno. Para la revisión, se realizaron búsquedas en las bases de datos electrónicas Scielo, Pepsic y Lilacs, y artículos científicos que abordaron el equilibrio entre el trabajo y la familia durante la pandemia de COVID-19. Para la investigación empírica, 38 PGP/SO participaron en el estudio, quienes respondieron un cuestionario en línea. Las respuestas fueron analizadas mediante análisis de contenido temático. RESULTADOS: Se identificó, en vista de los teletrabajadores, cambios en la dinámica trabajo-familia, dificultades financieras, necesidad de utilizar nuevas tecnologías para realizar el trabajo, daños a la salud mental, cuestiones relacionadas con el género y posibles estrategias de afrontamiento. Desde el punto de vista de PGP/SO, los trabajadores tenían dificultades para conciliar el trabajo familiar. La falta de equipos y entornos adecuados influyó negativamente en la productividad. CONCLUSIÓN: Se cree que el escenario de pandemia, asociado al aumento de la jornada laboral y a las demandas excesivas de productividad, ha aumentado el nivel de tensión y estrés entre los individuos, generando un desequilibrio en los ámbitos familiar y ocupacional.

Modified application of interface screw in femoral side during anterior cruciate ligament reconstruction / 中国骨伤

OBJECTIVE@#To compare clinical effects of the improved interface screw fixation of femoral end of anterior cruciate ligament with classic femoral lateral loop plate fixation.@*METHODS@#A retrospective analysis of 65 patients who underwent arthroscopic anterior cruciate ligament reconstruction from January 2019 to September 2021 were performed. According to the different fixation methods of the femoral side, 35 patients were divided into loop plate fixation(loop plate group), including 27 males and 8 females, aged from 18 to 50 years old with an average of (35.00±7.60) years old;30 patients in interface screw fixation(interface screw group), including 20 males and 10 females, aged from 18 to 50 years old with an average of (32.00±8.50) years old. Hospital stay, hospital expenses, operation time, complications, C-reactive protein at 1, 3, 6 days after operation, and postoperative Lysholm score and International Knee Documentation Committee(IKDC) score at 18 months were compared between two groups.@*RESULTS@#All patients were successfully operated, and obtained follow-up from 18 to 36 months with an average of (25.16±4.50) months. Anterior drawer test and Lachman test of all patients turned to negative. There were no statistical differences in hospital stay, hospital expenses and complications between two groups(P>0.05);operation time in loop plate group was (74.00±6.84) min, and (91.67±6.34) min in interface screw group, and had difference between two groups(P<0.05). C-reactive protein on the 1st and 3rd day after operation was (40.00±10.10), (20.00±8.23) mg·L-1 in loop plate group, and (60.00±8.93), (30.00±8.66) mg·L-1 in interface nail group, had statistical difference between two groups (P<0.05);while there was no difference in C-reactive protein on the 6th day after operation(P>0.05). At 18 months after operation, Lysholm and IKDC scores showed no significant difference between two groups (P>0.05). In loop plate group, medullary enlargement on coronal and sagittal views were (2.75±0.19) mm, (1.55±0.25) mm, and (2.81±0.22) mm, (1.61±0.20) mm in interface screw group, and had statistical difference between two groups(P<0.05).@*CONCLUSION@#In the reconstruction of anterior cruciate ligament, the common interface screw on the femoral side is changed to the sheath interface screw, and intramedullary screw is changed to the compression and fixation of tendon from outside to inside of joint. Although the operation procedure is relatively complicated and operation time is slightly longer, it has advantages of no residual metal foreign body after operation, and clinical effect is no different from classical loop plate suspension fixation, which is still a good choice.

Targeted muscle reinnervation: a surgical technique of human-machine interface for intelligent prosthesis / 中国修复重建外科杂志

OBJECTIVE@#To review targeted muscle reinnervation (TMR) surgery for the construction of intelligent prosthetic human-machine interface, thus providing a new clinical intervention paradigm for the functional reconstruction of residual limbs in amputees.@*METHODS@#Extensively consulted relevant literature domestically and abroad and systematically expounded the surgical requirements of intelligent prosthetics, TMR operation plan, target population, prognosis, as well as the development and future of TMR.@*RESULTS@#TMR facilitates intuitive control of intelligent prostheses in amputees by reconstructing the "brain-spinal cord-peripheral nerve-skeletal muscle" neurotransmission pathway and increasing the surface electromyographic signals required for pattern recognition. TMR surgery for different purposes is suitable for different target populations.@*CONCLUSION@#TMR surgery has been certified abroad as a transformative technology for improving prosthetic manipulation, and is expected to become a new clinical paradigm for 2 million amputees in China.

Research progress of brain-computer interface application paradigms based on rapid serial visual presentation / 生物医学工程学杂志

Rapid serial visual presentation (RSVP) is a type of psychological visual stimulation experimental paradigm that requires participants to identify target stimuli presented continuously in a stream of stimuli composed of numbers, letters, words, images, and so on at the same spatial location, allowing them to discern a large amount of information in a short period of time. The RSVP-based brain-computer interface (BCI) can not only be widely used in scenarios such as assistive interaction and information reading, but also has the advantages of stability and high efficiency, which has become one of the common techniques for human-machine intelligence fusion. In recent years, brain-controlled spellers, image recognition and mind games are the most popular fields of RSVP-BCI research. Therefore, aiming to provide reference and new ideas for RSVP-BCI related research, this paper reviewed the paradigm design and system performance optimization of RSVP-BCI in these three fields. It also looks ahead to its potential applications in cutting-edge fields such as entertainment, clinical medicine, and special military operations.

Recognition of motor imagery electroencephalogram based on flicker noise spectroscopy and weighted filter bank common spatial pattern / 生物医学工程学杂志

Due to the high complexity and subject variability of motor imagery electroencephalogram, its decoding is limited by the inadequate accuracy of traditional recognition models. To resolve this problem, a recognition model for motor imagery electroencephalogram based on flicker noise spectrum (FNS) and weighted filter bank common spatial pattern ( wFBCSP) was proposed. First, the FNS method was used to analyze the motor imagery electroencephalogram. Using the second derivative moment as structure function, the ensued precursor time series were generated by using a sliding window strategy, so that hidden dynamic information of transition phase could be captured. Then, based on the characteristic of signal frequency band, the feature of the transition phase precursor time series and reaction phase series were extracted by wFBCSP, generating features representing relevant transition and reaction phase. To make the selected features adapt to subject variability and realize better generalization, algorithm of minimum redundancy maximum relevance was further used to select features. Finally, support vector machine as the classifier was used for the classification. In the motor imagery electroencephalogram recognition, the method proposed in this study yielded an average accuracy of 86.34%, which is higher than the comparison methods. Thus, our proposed method provides a new idea for decoding motor imagery electroencephalogram.

Applications and challenges of wearable electroencephalogram signals in depression recognition and personalized music intervention / 生物医学工程学杂志

Rapid and accurate identification and effective non-drug intervention are the worldwide challenges in the field of depression. Electroencephalogram (EEG) signals contain rich quantitative markers of depression, but whole-brain EEG signals acquisition process is too complicated to be applied on a large-scale population. Based on the wearable frontal lobe EEG monitoring device developed by the authors' laboratory, this study discussed the application of wearable EEG signal in depression recognition and intervention. The technical principle of wearable EEG signals monitoring device and the commonly used wearable EEG devices were introduced. Key technologies for wearable EEG signals-based depression recognition and the existing technical limitations were reviewed and discussed. Finally, a closed-loop brain-computer music interface system for personalized depression intervention was proposed, and the technical challenges were further discussed. This review paper may contribute to the transformation of relevant theories and technologies from basic research to application, and further advance the process of depression screening and personalized intervention.

A design and evaluation of wearable p300 brain-computer interface system based on Hololens2 / 生物医学工程学杂志

Patients with amyotrophic lateral sclerosis ( ALS ) often have difficulty in expressing their intentions through language and behavior, which prevents them from communicating properly with the outside world and seriously affects their quality of life. The brain-computer interface (BCI) has received much attention as an aid for ALS patients to communicate with the outside world, but the heavy device causes inconvenience to patients in the application process. To improve the portability of the BCI system, this paper proposed a wearable P300-speller brain-computer interface system based on the augmented reality (MR-BCI). This system used Hololens2 augmented reality device to present the paradigm, an OpenBCI device to capture EEG signals, and Jetson Nano embedded computer to process the data. Meanwhile, to optimize the system's performance for character recognition, this paper proposed a convolutional neural network classification method with low computational complexity applied to the embedded system for real-time classification. The results showed that compared with the P300-speller brain-computer interface system based on the computer screen (CS-BCI), MR-BCI induced an increase in the amplitude of the P300 component, an increase in accuracy of 1.7% and 1.4% in offline and online experiments, respectively, and an increase in the information transfer rate of 0.7 bit/min. The MR-BCI proposed in this paper achieves a wearable BCI system based on guaranteed system performance. It has a positive effect on the realization of the clinical application of BCI.

Recognition of high-frequency steady-state visual evoked potential for brain-computer interface / 生物医学工程学杂志

Coding with high-frequency stimuli could alleviate the visual fatigue of users generated by the brain-computer interface (BCI) based on steady-state visual evoked potential (SSVEP). It would improve the comfort and safety of the system and has promising applications. However, most of the current advanced SSVEP decoding algorithms were compared and verified on low-frequency SSVEP datasets, and their recognition performance on high-frequency SSVEPs was still unknown. To address the aforementioned issue, electroencephalogram (EEG) data from 20 subjects were collected utilizing a high-frequency SSVEP paradigm. Then, the state-of-the-art SSVEP algorithms were compared, including 2 canonical correlation analysis algorithms, 3 task-related component analysis algorithms, and 1 task discriminant component analysis algorithm. The results indicated that they all could effectively decode high-frequency SSVEPs. Besides, there were differences in the classification performance and algorithms' speed under different conditions. This paper provides a basis for the selection of algorithms for high-frequency SSVEP-BCI, demonstrating its potential utility in developing user-friendly BCI.

Effects of Fretting Stimulation Amplitude on Bone Growth and Micro-Injury at the Interface Between Bone Tissues and TitaniuBead Coating / 医用生物力学

Objective To improve the performance of artificial joint at biological fixed interface by frettingmechanical stimulation. Methods Taking the bonding sample of active rat bone tissues and inactive titanium bead coating as the research object, by using the self-developed fretting mechanical stimulation test device, the effects of mechanical stimulation with different tangential fretting amplitudes on growth promotion and micro-injury of bone tissues at fixed interface were explored, and the mechanism of growth promotion and micro-injury of bonetissues on the surface of titanium bead coating under fretting stimulation was revealed. Results The mechanical stimulation group with 40 μm fretting amplitude showed the maximum interface bonding force between bone tissues and titanium bead coating. The tangential fraction force-displacement curves changed from elliptic shape to linear shape, and the bonding interface was in adhesion area, which was difficult to become loose. The bone tissues had the most complete structure, and the number of tissue cells adhering and growing on the surface of titanium bead coating was the largest, as well as the distribution range was the widest. With the increase of fretting amplitude, the promoting effect of fretting stimulation on bone growth weakened, the bonding strength between bone tissues and titanium bead coating interface gradually decreased, the internal cavity area increased, the number and proliferation activity of tissue cells decreased to varying degrees as well. Conclusions Fretting stimulation with different amplitudes can promote the growth of bone tissue and cause micro-injury at the same time, and the optimal fretting amplitude is 40 μm.

Numerical Simulation of In-Plane Crack Propagation in Aortic Dissection / 医用生物力学

Objective Based on interface damage, a numerical simulation method for in-plane propagation of false lumen (FL) was proposed to explore the regular pattern of in-plane propagation of the initial cavity. Methods Three interface damage modes were characterized by bi-linear traction separation law, and the damage parameters were calibrated by simulating peeling and shearing tests. The damage interface was introduced into the ideal double-layer cylindrical tube aortic model by means of cohesive zone model (CZM) to simulate the in-plane propagation of FL. The control variable method was used to establish several computational models to investigate the influence of cavity geometric parameters on propagation direction, critical pressure and interface damage mode. Results The interface damage was mainly opening mode (Mode I) in axial propagation and sliding mode (Mode II) in circumferential propagation. With radial depth of the initial cavity increasing, the propagation of the FL changed from circumferential direction to axial direction, the critical pressure decreased, and the axial damage tended to be pure opening mode. With circumferential angle and axial length of the initial cavity increasing, the critical pressure decreased and the circumferential damage tended to be pure sliding mode. The critical pressure of single damage was lower than that of mixed damage. Conclusions The CZM can effectively characterize interface damage behavior of elastic lamellae within the media, and it applies to numerical simulation of in-plane propagation of the FL. The results of this study is helpful to understand the complex pathophysiological process of dissection crack propagation.

Improving the recognition of vitreoretinal interface in children / 中华眼底病杂志

Vitreoretinal interface is consisted of posterior vitreous cortex, retina internal limiting membrane, and extracellular matrix between them. Basement membrane-like complex is formed in the interface. The interface in children is of much difference with that in adult. The adhesion of it is much tight in children. The posterior edge of vitreous base is closed to ora serrata. The retina internal limiting membrane is thin. But with age, the posterior margin of vitreous base extends posteriorly, internal limiting membrane thickens and its elasticity decreases, the adhesion in vitreoretinal interface weakens, and posterior vitreous detachment develops. To recognize fully the interface in children is of much importance for understanding the pathophysiology and treatment strategy of pediatric vitreoretinal diseases.

Research methods and progress of gradient multiphase scaffold materials promoting rotator cuff tenon-bone interface repair and regeneration / 中华骨科杂志

Regeneration of rotator cuff tendon-bone interface is crucial in rotator cuff repair. The tendon-bone interface consists of four continuous and gradual regions: the tendon region, the unmineralized fibrocartilage region, the mineralized fibrocartilage region, and the bone region. The development and regeneration of various regions in the tendon-bone interface is regulated by growth factors, inorganic ions, mechanical stimulation, and hypoxic environment. Inspired by factors affecting the development and regeneration of the tendon-bone interface, many researchers have designed gradient scaffold systems that promote regionalized regeneration of the tendon-bone interface. The gradient distribution of these scaffolds includes inorganic ion gradients and growth factor gradients. According to different gradients of the scaffold system, osteogenesis, chondrogenesis and tendon differentiation of cells at the tendon-bone interface are promoted, and the healing of the tendon-bone is synchronously completed to realize the repair and regeneration of the rotator cuff tendon-bone interface. Current studies indicated that gradient multiphase scaffolds had high academic research value and guided significance for future clinical applications in the reconstruction of the tendon-bone interface. In this paper, the factors affecting the development and regeneration of the tendon-bone interface are reviewed, and the effects of these factors on osteogenesis, chondrogenesis and tendon formation of various regions in promoting rotator cuff tendon-bone interface repair are summarized. The properties and effects of reported gradient multiphase scaffolds for rotator cuff injury are discussed, including gradient scaffolds containing inorganic ions and growth factors. Finally, the problems and future development opportunities of gradient multiphase support in rotator cuff repair are summarized.

The past,present,and future of in vivo-implant-able recording microelectrodes:the neural interfaces / 中国药理学与毒理学杂志

Neural recording electrodes enable the acquisition and collection of electrical signals from neu-rons,and these recorded neural electrical signals are an important means of understanding neuronal activity.As a major component of the brain-machine interface,neu-ral recording electrodes serve as a bridge between the nervous system and external devices.The extracted information can be used to understand the state of the brain and acts as a feedback signal to regulate external devices,thus providing important information for the clini-cal treatment of neurological diseases.Moreover,the electrodes can be used as a vehicle for drug injection to directly treat diseases.Since the time that Strumwas-ser used microwires to achieve long-term recordings of neural activity in hibernating squirrels,implantable elec-trode technology has gradually improved over three gen-erations of development,and progress has been made in improving the biocompatibility,mechanical performance(size,shape,density,etc.),and signal-to-noise ratio.Implantable neural recording electrodes can acquire sig-nals from cortical and deep neural clusters,with the advantages of high signal-to-noise ratio,information con-tent,and spatial/temporal resolution.However,there is still a need to improve the structure and performance of these electrodes;for example,their high invasiveness and lack of biocompatibility pose technical difficulties in the process of translation to the clinic.This paper reviews the basic requirements for electrodes,main recording methods and signal types,common types of implant-able neural recording electrodes,and their challenges and future development directions.With the continuous development of electrode materials,equipment,systems,and neurotechnology,it should be possible to apply neu-ral recording electrodes in clinical practice,to promote safe and efficient treatment of human diseases.

Comparison of different approaches for direct coupling of solid-phase microextraction to mass spectrometry for drugs of abuse analysis in plasma / 药物分析学报

The direct coupling of solid-phase microextraction(SPME)to mass spectrometry(MS)(SPME-MS)has proven to be an effective method for the fast screening and quantitative analysis of compounds in complex matrices such as blood and plasma.In recent years,our lab has developed three novel SPME-MS techniques:SPME-microfluidic open interface-MS(SPME-MOI-MS),coated blade spray-MS(CBS-MS),and SPME-probe electrospray ionization-MS(SPME-PESI-MS).The fast and high-throughput nature of these SPME-MS technologies makes them attractive options for point-of-care analysis and anti-doping testing.However,all these three techniques utilize different SPME geometries and were tested with different MS instruments.Lack of comparative data makes it difficult to determine which of these methodologies is the best option for any given application.This work fills this gap by making a comprehensive comparison of these three technologies with different SPME devices including SPME fibers,CBS blades,and SPME-PESI probes and SPME-liquid chromatography-MS(SPME-LC-MS)for the analysis of drugs of abuse using the same MS instrument.Furthermore,for the first time,we developed different desorption chambers for MOI-MS for coupling with SPME fibers,CBS blades,and SPME-PESI probes,thus illustrating the universality of this approach.In total,eight analytical methods were developed,with the experimental data showing that all the SPME-based methods provided good analytical performance with R2 of linearities larger than 0.9925,accuracies between 81％and 118％,and good precision with an RSD％≤13％.

Brain-computer interface coding method based on high-frequency dual-frequency SSVEP / 国际生物医学工程杂志

Objective:To improve the users’ comfort of steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) through high-frequency stimulation and overcome the problem of accuracy decline caused by high frequency by combining dual-frequency encoding.Methods:Two dual-frequency high-frequency 60-instruction paradigms based on left and right visual fields and checkerboard stimuli were designed based on the 25.5 - 39.6 Hz frequency. Thirteen subjects participated in the experiment, and spectrum and spatial characteristics analyses were performed on SSVEP signals. The filter bank parameters were optimized based on the spectrum characteristics. Extended canonical correlation analysis (eCCA), ensemble task-related component analysis (eTRCA), and task-discriminant component analysis (TDCA) were used for SSVEP recognition.Results:Stable SSVEP was successfully induced in both the left and right visual fields and the checkerboard grid paradigm. The left and right visual fields had high signal-to-noise ratios for the fundamental frequency and its harmonics and weak signal-to-noise ratios for intermodulation components, whereas the intermodulation components of the 2 stimulus frequencies of the checkerboard grid, f1 + f2, had significantly higher signal-to-noise ratios than the second harmonic components above 30 Hz, and there was also a f2 ? f1 component and a 2 f1 ? f2 component. Combined with brain topography, it can be seen that the f1 and f2 response components of the left and right visual fields are located on opposite sides of the visual field, while the checkerboard grids are both concentrated in the center of the occipital region. Regarding the lateralization of brain topography amplitude and signal-to-noise ratio, the mean values of the PO3 and PO4 signal-to-noise ratios at the stimulation frequency of the left and right visual fields are consistent with the contralateral response characteristics. The 5 fb ? 1 method is the optimal filter set setting method, and the recognition correctness rate of TDCA for the left and right visual fields is the highest. However, the comparison of the recognition correctness rate of tessellated lattice eTRCA and TDCA is not statistically significant ( P > 0.05). The information transmission rates of the three algorithms all increase and then decrease with the increase in data length. Conclusions:The designed dual-frequency, high-frequency SSVEP-BCI paradigm is able to better balance performance and comfort and provides a basis for practical large instruction set BCI design methods.