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.

Advances in brain-computer interface based on high-frequency steady-state visual evoked potential / 生物医学工程学杂志

Steady-state visual evoked potential (SSVEP) has been widely used in the research of brain-computer interface (BCI) system in recent years. The advantages of SSVEP-BCI system include high classification accuracy, fast information transform rate and strong anti-interference ability. Most of the traditional researches induce SSVEP responses in low and middle frequency bands as control signals. However, SSVEP in this frequency band may cause visual fatigue and even induce epilepsy in subjects. In contrast, high-frequency SSVEP-BCI provides a more comfortable and natural interaction despite its lower amplitude and weaker response. Therefore, it has been widely concerned by researchers in recent years. This paper summarized and analyzed the related research of high-frequency SSVEP-BCI in the past ten years from the aspects of paradigm and algorithm. Finally, the application prospect and development direction of high-frequency SSVEP were discussed and prospected.

Research on phase modulation to enhance the feature of high-frequency steady-state asymmetric visual evoked potentials / 生物医学工程学杂志

High-frequency steady-state asymmetric visual evoked potential (SSaVEP) provides a new paradigm for designing comfortable and practical brain-computer interface (BCI) systems. However, due to the weak amplitude and strong noise of high-frequency signals, it is of great significance to study how to enhance their signal features. In this study, a 30 Hz high-frequency visual stimulus was used, and the peripheral visual field was equally divided into eight annular sectors. Eight kinds of annular sector pairs were selected based on the mapping relationship of visual space onto the primary visual cortex (V1), and three phases (in-phase[0º, 0º], anti-phase [0º, 180º], and anti-phase [180º, 0º]) were designed for each annular sector pair to explore response intensity and signal-to-noise ratio under phase modulation. A total of 8 healthy subjects were recruited in the experiment. The results showed that three annular sector pairs exhibited significant differences in SSaVEP features under phase modulation at 30 Hz high-frequency stimulation. And the spatial feature analysis showed that the two types of features of the annular sector pair in the lower visual field were significantly higher than those in the upper visual field. This study further used the filter bank and ensemble task-related component analysis to calculate the classification accuracy of annular sector pairs under three-phase modulations, and the average accuracy was up to 91.5%, which proved that the phase-modulated SSaVEP features could be used to encode high- frequency SSaVEP. In summary, the results of this study provide new ideas for enhancing the features of high-frequency SSaVEP signals and expanding the instruction set of the traditional steady state visual evoked potential paradigm.

Traditional Chinese Medicine's "Yipingweiqi" Adjusts Homeostasis of Tumor Immune Microenvironment / 肿瘤防治研究

Tumor immune microenvironment has been the focus of tumor research in recent years, and its role in tumor regulation has become prominent and has received increasing attention. The imbalance of the tumor immune microenvironment plays an important role in promoting tumor progression, and the adjustment of its instability plays an important role in controlling tumor progression. The theoretical idea of Traditional Chinese Medicine's "Yipingweiqi" is basically the same as that of modern medicine of controlling tumors by maintaining the balance of the immune microenvironment. This study discusses the aspects of tumor immune microenvironment, its destabilization, relationship to tumor progression, importance in Traditional Chinese Medicine, and regulation by Traditional Chinese Medicine with different treatments. In particular, this work focuses on the role of Traditional Chinese Medicine in maintaining the balance of the tumor immune microenvironment and its potential mechanism by using qi benefit, yang warming, dampness eliminating, and heat clearing under the guidance of the principle of "Yipingweiqi". Results will provide reference for the application of Traditional Chinese Medicine in the diagnosis and treatment of tumors.

A descrição teórica da determinação eletroquímica do fármaco perilartina, assistida pelo oxihidróxido de cobalto, emparelhado com o seu dióxido

Introdução: perilartina é um adoçante natural potente, considerado 2000 vezes mais doce que o açúcar comum. Ela pode ser alérgica para algumas pessoas. Além disso, ela se usa apenas no Japão, o que pressupõe a possibilidade de adulterar produtos japoneses sem o seu uso. Assim, o desenvolvimento de um método eficiente da sua determinação qualificativa e quantificação é realmente atual. Metodologia: um modelo matemático de um processo anódico foi desenvolvido e analisado mediante a teoria de estabilidade linear e análise de bifurcações. O modelo inclui os cenários mais prováveis do andamento do processo eletroanalítico. Resultados: a perilartina é oxidada no meio básico, formando o poliol e o sal do "pseudoácido" correspondente, o que contribui fortemente para a força iônica da dupla camada elétrica. Isto pode ser responsável pela aparição das instabilidades oscilatória e monotônica no processo eletroanalítico. Conclusão: malgrado o supracitado, o compósito é um modificador eficiente para a determinação eletroquímica da perilartina no meio básico.

Introducción: perilartina es un edulcorante natural potente, considerado 2000 veces más dulce que el azúcar común. Esta puede causar alergia a algunas personas. Además, ella solo se usa en Japón, lo que presupone la posibilidad de falsificar productos japoneses sin su uso. Así, el desarrollo de un método eficiente de su determinación cuantitativa y cualitativa es realmente actual. Metodología: un modelo matemático de un proceso anódico fue desarrollado y analizado mediante la teoría de estabilidad lineal e análisis de bifurcaciones. El modelo incluye los escenarios más probables del curso del proceso electroanalítico. Resultados: la perilartinase oxida en el medio básico, formando el poliol y la sal del "pseudoácido" correspondiente, lo que contribuye fuertemente para la fuerza iónica de la doble capa eléctrica. Esto puede ser responsable por la aparición de las inestabilidades oscilatoria y monotónica en el proceso electroanalítico. Conclusión: a pesar de lo mencionado, el compuesto es un modificador eficaz para la determinación electroquímica de la perilartina en el medio básico.

SUMMARY Introduction: Perillartine is a strong natural sweetener, considered 2000 as sweet as a common sugar. It may be allergic to some people. Also, it is used only in Japan, which may presuppose the possibility of falsify Japanese products without its use. Thus the development of an eficiente method of its quantitative and qualitative determination is really actual. Methodology: A mathematical model of an anodic process has been developed and analyzed by means of linear stability theory and bifurcation analysis. The model includes the most probable scenarios of the course of the electroanalytical process. Results: Perillartine is oxidized in basic media, yielding the polyol and the correspondent pseudoacid salt, which strongly contributes to the double electric layer ionic force. This may be responsible for the oscillatory and monotonic instabilities appearance in the electroanalytical process. Conclusion: Despite of the above mentioned statements, the composite is na efficient modifier for the electrochemical determination of perillartine in basic media.

A conversão eletrocatalítica de etanal em glioxal. Uma avaliação teórica

Introdução: uma proposta de modificação da síntese industrial de glioxal, o dial-deído mais simples, amplamente usado nas indústrias cosmética e farmacêutica, tem sido avaliada teoricamente. Trata-se, de fato, de uma adaptação de um método químico para a síntese eletroorgânica no ânodo, modificado por um revestimento polimèrico condutor, dopado pelo íon selenito. Metodologia: o modelo matemático correspondente tem sido desenvolvido e analisado mediante a teoria de estabilidade linear e análise de bifurcações. O conjunto de equações de balanço, para o modo potenciostático é bivariante. Resultados: foi provado que as capacitâncias da dupla camada elétrica (DCE) vêm sendo afetada tanto na etapa eletroquímica como na química. Essas influências são responsáveis pela aparição do comportamento osci-latório no sistema. Por outro lado, o estado estacionário se estabelece e se mantém facilmente, indicando um processo eletrocatalítico eficiente e com rendimento superior ao do processo químico. Conclusão: o elétrodo polimérico condutor, dopado pelo íon selenito é uma ferramenta eficiente para a conversão eletroorgânica do etanal em glioxal. Ao contrário do método clássico, este processo pode ser usado em escala industrial.

SUMMARY Introduction: A proposal for industrial synthesis for glyoxal, the simplest dialdehyde, widely used in cosmetics and pharmaceutical industry, has been theoretically evaluated. In fact, this is an adaptation of a chemical method for electroorganic synthesis over an anode, modified by a conducting polymer coating, doped by the selenite-ion. Methodology: A correspondent mathematical model has been developed and analyzed by means of linear stability theory and bifurcation analysis. The balance equation-set for potentiostatic mode is bivariant. Results: It was proven that the double electric layer (DEL) capacitances are affected on both electrochemical and chemical stages. These influences are responsible for the appearance of the oscillatory behavior in the system. On the other hand, the steady-state becomes stable and maintains stable, indicating an efficient electroorganic method. The yield is expected to be higher than for the chemical system. Conclusion: The selenite-doped conducting polymer electrode is an efficient tool for ethanal electroorganic conversion into glyoxal. Contrarily to the classic method, it may be used in industrial scale.

Introducción: una propuesta de síntesis industrial de glioxal se ha evaluado teóricamente, este es el dialdehído más simple y es ampliamente utilizado en la industria cosmética y farmacéutica. De hecho, se trata de una adaptación de un método químico de síntesis electroorgánica sobre un ánodo, modificado por un recubrimiento de polímero conductor, dopado por el ion selenito. Metodología: se ha desarrollado y analizado un modelo matemático adecuado mediante la teoría de la estabilidad lineal y el análisis de bifurcaciones. El conjunto de ecuaciones de equilibrio para el modo potenciostático es bivariante. Resultados: se comprobó que las capacitancias de doble capa eléctrica (DEL) se ven afectadas tanto en las etapas electroquímicas como químicas. Estas influencias son las responsables de la aparición del comportamiento oscilatorio en el sistema. Por otro lado, el estado estacionario se vuelve estable y se mantiene estable, lo que indica un método electroorgá-nico eficiente. Se espera que el rendimiento sea mayor que para el sistema químico. Conclusión: el electrodo de polímero conductor dopado con selenita es una herramienta eficiente para la conversión electroorgánica de etanal en glioxal. A diferencia del método clásico, puede utilizarse a escala industrial.

Descripción teórica del desempeño electroanalítico del material compuesto de oxihidróxido de vanadio con el colorante escuárico en la detección de la carfedona

Introducción: en este trabajo se evalúa desde el punto de vista mecanístico teórico el comportamiento electroanalítico del compuesto oxihidróxido de vanadio-colorante escuárico en la detección de la carfedona. El proceso electroanalítico incluye la formación de dos formas de vanadio tetravalente, incluyendo el dióxido de vanadio e ion vanadilo. Método: un mecanismo, capaz de describir el comportamiento del sensor, ha sido sugerido y un modelo matemático fue desarrollado y analizado mediante la teoría de estabilidad lineal y análisis de bifurcaciones. Resultados: el análisis del modelo ha probado que la dependencia lineal entre la concentración del fármaco y el parámetro electroquímico se mantiene firme en la ancha región topo-lógica de parámetros. Las inestabilidades oscilatoria y monotónica suelen realizarse cuando son causadas por influencias fuertes de las etapas química y electroquímica en la capacitancia de la doble capa eléctrica. Conclusiones: el compuesto de nano-partículas de oxihidróxido de vanadio (estabilizadas con el colorante escuárico) puede servir como un modificador eficiente de electrodo para la detección de la carfedona. El oxihidróxido de vanadio desempeña funciones de sustancia activa y el colorante, de la mediadora.

SUMMARY Introduction: In this work, the electroanalytical behavor of the vanadium oxyhydroxide-squaraine dye composite for the carfedon detection is evaluated. The electroanalytical process includes the formation of two tetravalent vanadium forms, including vanadium dioxide and vanadylion. Methods: A mechanism, capable to describe the sensor behavior, has been suggested, and the correspondent mathematical model has been developed and analyzed by means of the linear stability theory and bifurcation analysis. Results: The model analysis has proved that the linear dependence between the drug concentration and the concentration is firmly maintained in a wide topological parameter region. As for the oscillatory and monotonic instabilities, they may be realized, being caused by strong influences of the chemical and electrochemical stages on double electric layer capacitance. Conclusions: The vanadium oxyhydroxide composite with the squaraine dye may serve as an efficient electrode modifier for carfedone determination. The vanadium oxyhydroxide works as an active substance and the dye as a mediator.

Introdução: neste trabalho, avalia-se, do ponto de vista mecanístico teórico, o comportamento eletroanalítico do compósito oxihidróxido do vanádio-corante esquárico na detecção da carfedona. O processo eletroanalítico inclui a formação de duas formas do vanádio tetravalente, incluindo o dióxido de vanádio e íon vanadila. Método: um mecanismo, capaz de descrever o comportamento do sensor, tem sido sugerido e um modelo matemático correspondente, desenvolvido e analisado por meio da teoria de estabilidade linear e análise de bifurcações. Resultados: a análise do modelo tem provado que a dependência linear entre a concentração do fármaco e o parâmetro eletroquímico se mantém firme numa ampla região topológica de parâmetros. Já as instabilidades oscilatória e monotônica soem realizar-se, sendo causadas pelas influências fortes das etapas química e electroquímica na capacitância da dupla camada elétrica. Conclusões: o compósito de nanopartículas do oxihidróxido de vanádio, estabilizadas pelo corante esquárico, pode servir de um modificador eficaz para a detecção da carfedona. O oxihidróxido de vanádio desempenha as funções de substância ativa, e o corante, de mediador.

Applying kurtosis-adjusted equivalent continuous A-weighted sound pressure level to evaluate risk of occupational hearing loss associated with non-steady state noise / 环境与职业医学

Background Equivalent continuous A-weighted sound pressure level is not appropriate for evaluating the risk of non-steady noise exposure, and need to be corrected by noise time-domain structure, but the correction method and its applicability need to be discussed. Objective To validate the application of the kurtosis-adjusted normalization of equivalent continuous A-weighted sound pressure level to a normal 8 h working day ( LAeq,8 h) in assessing noise-induced hearing loss (NIHL), and to improve the methods for assessing occupational hearing loss associated with different types of noise. Methods Audiometric and shift-long noise exposure data were acquired from a population(n=2 466) of screened workers exposed to noise between 70 dB(A) and 95 dB(A) from 6 industries in China. The cohort data were collapsed into 1 dB(A) bins, and the average kurtosis and noise-induced permanent threshold shifts at 3 kHz, 4 kHz, and 6 kHz (NIPTS346) within 1 dB(A) were calculated respectively. According to the existing correction method, the adjustment coefficient λ was calculated by multiple regression, and LAeq,8 h was corrected by λ (L'Aeq,8 h). The entire cohort was divided into K1 (≤10; steady noise), K2 (10~50; non-steady noise), and K3 (＞50; non-steady noise) groups based on mean kurtosis levels. Predicted NIPTS346 was calculated using the ISO 1999 model for each participant and the actual measured NIPTS346 was corrected for age and gender. The underestimated NIPTS346 was the difference between the values of estimated NIPTS346 and the corresponding actual NIPTS346. To validate the applicability of L′Aeq,8 h in evaluating NIHL, the correlation between L′Aeq,8 h and HFNIHL, and the mean difference between real NIPTS346 and estimated NIPTS346 were analyzed. Results The adjustment coefficient λ was determined at 5.43. The results of multiple logistic regression analysis showed that the relationship between L'Aeq,8 h and HFNIHL increased from 6.6% to 9.6% after the kurtosis adjustment. The DRR of LAeq,8 h and HFNIHL showed that the percentage of HFNIHL decreased after the adjustment of kurtosis in the non-steady noise groups, and the regression lines of the non-steady noise groups approached that of the steady noise group. The R2 of the K2 group increased from 0.935 3 to 0.986 3, and the R 2 of the K3 group increased from 0.905 6 to 0.951 6. Under the un-adjusted condition, the NIPTS346 underestimation for the K3 group was significantly higher than that for the steady noise group (t=−3.23, P=0.001). After the LAeq,8 h was adjusted by kurtosis, the NIPTS346 underestimation decreased significantly in the three kurtosis groups (K1: t=6.78, P＜0.001; K2: t=14.31, P＜0.001; K3: t=11.06, P＜0.001). There was no significant difference in the degree of underestimation between the three kurtosis groups (K1 vs K2: t=−0.22, P=0.830; K1 vs K3: t=−1.40, P=0.205) as the curves of the three kurtosis groups were nearly overlapped. Conclusion The kurtosis-adjusted LAeq,8 h can effectively estimate the hearing loss associated with non-steady state noise.

Characteristics of auditory steady-state response in first-degree relatives of schizophrenic patients under eye-open/closed state / 中华行为医学与脑科学杂志

Objective:To study the effect of eye-open/closed state on 40 Hz auditory steady state response (ASSR) in first-degree relatives of schizophrenia.Methods:Thirty-eight first-degree relatives of schizophrenic patients treated in Shanghai Mental Health Center from March 2010 to October 2011 were selected, and 31 healthy controls were recruited in the same period. All subjects were assessed with schizotypal personality questionnaire (SPQ). The 40 Hz EEG ASSR signals lasting for 3 min under open and closed eyes of all subjects were sequentially collected.Event-related spectrum perturbation (ERSP) and intertribal phase coherence (ITC) were used to evaluate ASSR. SPSS 22.0 software was used for statistical analysis. Two-way analysis of variance was used to compare ITC and ERSP between the two groups under open and closed eyes. Spearman correlation analysis was used to analyze the correlation between each measurement.Results:ITC in group main effect and group×the eye open/closed interaction effect were not significant (both P>0.05), but the main effect of eye-open and eye-closed was significant ( F(1, 67)=10.61, P=0.002). In the healthy control group, the ITC in eye-open state was significantly higher than that in eye-closed state ( P=0.014), and in the first-degree relatives group, the ITC in eye-open state was higher than that in eyes closed state ( P=0.039). ERSP in the main effect of eye-open and eye-closed ( F(1, 67)=0.195, P=0.660), group main effect ( F(1, 67) =0.627, P=0.431), group × the eye-open/closed interaction effect ( F(1, 67)= 1.034, P=0.313) was not significant. Spearman correlation analysis showed that there was no correlation between ERSP (eye open: r=-0.260, P=0.210; eye closed: r=-0.318, P=0.122), ITC (eye open: r=-0.248, P=0.232; eye closed: r=-0.260, P=0.209) and SPQ score in the healthy control group. There was also no correlation between ERSP (eye open: r=-0.387, P=0.226; eye closed: r=-0.363, P=0.238) or ITC (eye open: r=0.126, P=0.485; eye closed: r=0.096, P=0.595) and SPQ score in the first-degree relatives group of schizophrenia. Conclusion:The regulation pattern of 40 Hz ASSR in schizophrenic first-degree relatives is not significantly impaired in the eye-open/closed state, suggesting that the open/closed regulation pattern of 40 Hz ASSR may not be a potential marker for predicting the genetic high-risk prognosis of schizophrenia.

Vitamin D analogues activate vitamin D receptor/glutathione peroxidase 4 pathway to improve ventilator-induced lung injury in mice / 中华危重病急救医学

Objective:To investigate the role of vitamin D analogue paricalcitol in activating vitamin D receptor/glutathione peroxidase 4 (VDR/GPX4) pathway in ventilator-induced lung injury (VILI).Methods:Twenty-four male C57BL/6J mice were randomly divided into control group, high tidal volume (HVT) induced VILI model group (HVT group), paricalcitol control group (P group), and paricalcitol pretreatment group (P+HVT group), with 6 mice in each group. The mice were endotracheal intubated and ventilated at 40 mL/kg tidal volume to prepare VILI model, while those in the control group were intubated without ventilation. The mice in the P+HVT group were intraperitoneally injected with paricalcitol 0.2 μg/kg once a day 1 week before modeling, while those in the P group were intraperitoneally injected paricalcitol 0.2 μg/kg once a day for 1 week before the experiment. After ventilation for 4 hours, the mice were sacrificed for lung tissue collection. Lung injury was evaluated by wet/dry (W/D) ratio, hematoxylin-eosin (HE) staining and Masson staining. The expressions of VDR and GPX4 were determined by Western blotting and immunohistochemistry. Malondialdehyde (MDA) and glutathione (GSH) contents were determined by micro method.Results:After HVT for 4 hours, compared with the control group, lung injury score and W/D ratio were significantly higher (lung injury score: 0.430±0.035 vs. 0.097±0.025, lung W/D ratio: 4.860±0.337 vs. 3.653±0.332, both P < 0.05), collagen fiber deposition was significantly increased, the content of MDA in lung tissue was significantly increased (nmol/g: 212.420±8.757 vs. 97.073±5.308, P < 0.05), GSH content and the protein expressions and immunoreactive score (IRS) of VDR and GPX4 were significantly decreased [GSH (μg/g): 44.229±1.690 vs. 70.840±0.781; VDR protein (VDR/GAPDH): 0.518±0.029 vs. 0.762±0.081, GPX4 protein (GPX4/GAPDH): 0.452±0.032 vs. 0.649±0.034; IRS score: VDR was 4.168±0.408 vs. 10.167±0.408, GPX4 was 4.333±1.033 vs. 10.333±0.516; all P < 0.05], which meant that the mice in HVT group showed obvious lung injury. After VDR was activated by paricalcitol, compared with the HVT group, lung injury score and W/D ratio were significantly decreased (lung injury score: 0.220±0.036 vs. 0.430±0.035, lung W/D ratio: 4.015±0.074 vs. 4.860±0.337, both P < 0.05), collagen fiber deposition was reduced, MDA content in lung tissue was decreased (nmol/g: 123.840±8.082 vs. 212.420±8.757, P < 0.05), GSH content and the protein expressions and IRS score of VDR and GPX4 were significantly up-regulated [GSH (μg/g): 63.094±0.992 vs. 44.229±1.690; VDR protein (VDR/GAPDH): 0.713±0.056 vs. 0.518±0.029, GPX4 protein (GPX4/GAPDH): 0.605±0.008 vs. 0.452±0.032; IRS score: VDR was 9.000±0.632 vs. 4.168±0.408, GPX4 was 8.833±0.408 vs. 4.333±1.033; all P < 0.05], which meant that lung injury in P+HVT group was significantly improved. Conclusion:Vitamin D analogue paricalcitol ameliorates pulmonary oxidation-reduction imbalance by activating the VDR/GPX4 pathway, thereby alleviating VILI.

Folate levels in children with sickle cell anemia on folic acid supplementation in steady state and crises at a tertiary hospital in Enugu, Nigeria a prospective, comparative study

Folic acid supplementation is an integral aspect of the management of children with sickle cell anaemia (SCA) especially in Africa. In spite of this, there have been concerns about lower folate levels, especially during crisis. AimTo determine red cell folate levels of children with sickle cell anaemia in steady state and during crisis and compare with those with haemoglobin AA genotype. Method This study was prospective, hospital based, and comparative. Fifty children with sickle cell anaemia were recruited during crises and followed up until they met the criteria for attaining steady state. The controls were fifty children matched with those with SCA for age and gender and had haemoglobin AA genotype. Red cell folate estimation was done with the Electrochemiluminescence Immunoassay (ECLIA) method using the automated Roche Cobas e411 equipment. Results The median (IQR) red cell folate level in children during sickle cell crisis was 265.95 (134.50) ng/ml, which was significantly lower than the median (IQR) of 376.30 (206.85) ng/ml obtained during steady state. Most children with SCA (41 out of 50) had significantly higher folate levels during steady state (T=1081, Z-score= -4.660, p < 0.001). Median level of red cell folate was lower during anaemic crisis compared to vaso-occlusive crisis, though not significantly so (N(50), U = 214.00, Z-score= -1.077, p = 0.305). The median red cell folate level of normal controls was 343.55 (92.90) ng/ml, which was significantly lower than the 376.30 (206.85) ng/ml obtained during steady state (N(50), U= 209.00, Z-score= -7.177, p <0.001). Conclusion Median red cell folate levels of the study participants were within normal limits, though most children with SCA had significantly higher levels during steady state compared to crisis. Normal controls had significantly lower red cell folate levels than the children with SCA during steady state

A review of researches on decoding algorithms of steady-state visual evoked potentials / 生物医学工程学杂志

Brain-computer interface (BCI) systems based on steady-state visual evoked potential (SSVEP) have become one of the major paradigms in BCI research due to their high signal-to-noise ratio and short training time required by users. Fast and accurate decoding of SSVEP features is a crucial step in SSVEP-BCI research. However, the current researches lack a systematic overview of SSVEP decoding algorithms and analyses of the connections and differences between them, so it is difficult for researchers to choose the optimum algorithm under different situations. To address this problem, this paper focuses on the progress of SSVEP decoding algorithms in recent years and divides them into two categories-trained and non-trained-based on whether training data are needed. This paper also explains the fundamental theories and application scopes of decoding algorithms such as canonical correlation analysis (CCA), task-related component analysis (TRCA) and the extended algorithms, concludes the commonly used strategies for processing decoding algorithms, and discusses the challenges and opportunities in this field in the end.

Progresses and prospects on frequency recognition methods for steady-state visual evoked potential / 生物医学工程学杂志

Steady-state visual evoked potential (SSVEP) is one of the commonly used control signals in brain-computer interface (BCI) systems. The SSVEP-based BCI has the advantages of high information transmission rate and short training time, which has become an important branch of BCI research field. In this review paper, the main progress on frequency recognition algorithm for SSVEP in past five years are summarized from three aspects, i.e., unsupervised learning algorithms, supervised learning algorithms and deep learning algorithms. Finally, some frontier topics and potential directions are explored.

A descrição teórica da detecção eletroquímica do fármaco olanzapina, assistida pelo compósito do oxihidróxido de cobalto (III) com um corante esquaraínico

Introdução: a olanzapina é um dos fármacos antipsicóticos benzodiazepínicos mais usados no mundo. Apesar da sua eficiência, em concentrações excessivas, ela sói ser tóxica, como quaisquer outros fármacos desta classe. Assim, neste trabalho, se avaliou, pela primeira vez, a possibilidade da detecção eletroquímica do fármaco olanzapina, assistida pelo compósito do oxihidróxido de cobalto (III), emparelhado com o dióxido, com um corante esquaraínico. Método: o modelo matemático trivariante correspondente inclui dois cenários de oxidação do fármaco, possíveis para o caso, incluindo a eletropolimerização indireta da molécula da benzodiazepina condensada, bem como a oxidação do fármaco pelo átomo do enxofre. Este modelo tem sido desenvolvido e analisado mediante a teoria de estabilidade linear e análise de bifurcações. Resultados e discussão: a análise do modelo há mostrado que a hibridez do mecanismo do processo eletroanalítico, aliada à composição e descomposição dos compostos iônicos aquando da sua realização, aumenta a probabilidade da ocorrência do comportamento oscilatório, em relação ao caso mais simples e mais comum. No entretanto, a instabilidade oscilatória se realiza nos valores dos parâmetros, que estão além do limite de detecção. Por sua vez, o estado estacionário se obtém e se mantém facilmente, indicando um processo eletroanalítico eficiente, controlado pela difusão do analito. Conclusões: trata-se de um processo eletroanalítico eficiente, em que o composto de cobalto funciona como substância ativa, e o corante desempenha o papel de mediador

SUMMARY Introduction: olanzapine is one of the most used antipsychotic drugs in the world. Although it is efficient, it may be toxic in excess. Therefore, in this work the possibility of olanzapine electrochemical determination over an electrode, modified by the cobalt (III) oxyhydroxide in pair with its dioxide in a composite with squaraine dye. Methods: the trivariant correspondent mathematical model includes two scenarios of the drug oxidation, possible for the case, including the indirect electropolymerization of the condensed benzodiazepine molecule, like also its oxidation by sulfur atom. This model has been developed and analyzed by means of stability theory and bifurcation analysis. Results and discussion: the analysis of the model has shown that the mechanism hybridity of the electroanalytical process, alongside with the formation and decomposition of ionic compounds during its realization, augments the possibility for the oscillatory behavior realization, relatively to the simplest and commonest case. Nevertheless, the oscillatory instability is realized in parameter values far beyond the detection limit. On the other hand, the stable steady-state is easy to obtain and maintain, indicating an efficient electroanalytical process, controlled by the analyte diffusion. Conclusions: the electroanalytical process is efficient. The cobalt compound is acting as an active substance, and the dye is the mediator.

Introducción: la olanzapina es uno de los fármacos antipsicóticos más utilizados en el mundo. Aunque es eficaz, puede resultar tóxico en exceso. Por tanto, en este trabajo se plantea la posibilidad de la determinación electroquímica de olanzapina sobre un electrodo, modificado por el oxihidróxido de cobalto (III) en pareja con su dióxido en un composito con colorante de escuaraína. Métodos: el modelo matemático correspondiente incluye dos escenarios de oxidación del fármaco, posibles para el caso, que incluyen la electropolimerización indirecta de la molécula de benzodiazepina condensada, así como su oxidación por átomo de azufre. Este modelo ha sido desarrollado y analizado mediante teoría de estabilidad y análisis de bifurcación. Resultados y discusión: el análisis del modelo ha demostrado que el mecanismo de hibridación del proceso electroanalítico, junto con la formación y descomposición de compuestos iónicos durante su realización, aumenta la posibilidad de realización del comportamiento oscilatorio, relativamente al caso más simple y común. Sin embargo, la inestabilidad oscilatoria se realiza en valores de parámetros mucho más allá del límite de detección. Por otro lado, el estado estacionario estable es fácil de obtener y mantener, lo que indica un proceso electroanalítico eficiente, controlado por la difusión del analito. Conclusiones: el proceso electroanalítico es eficiente. El compuesto de cobalto actúa como sustancia activa y el colorante es el mediador.

A descrição matemática da detecção eletroquímica da ergina, assistida pelos novos derivados triazólicos, dopados pelo íon amavadina / The mathematical description for the ergin electrochemical detection, assisted by amavadin ion doped triazolic derivatives / Descripción matemática de la detección electroquímica de ergina, asistida por los nuevos derivados de triazol, dopados por el ión amavadina

RESUMO Introdução: Pela primeira vez, o processo eletroanalítico da detecção da ergina (LSA) sobre um elétrodo, modificado por um derivado triazólico, dopado pelo íon amavadina, tem sido descrito teoricamente. Métodos: O modelo matemático, correspondente ao desempenho do sensor, tem sido desenvolvido e analisado do ponto de vista da teoria de estabilidade linear. Foi mostrado que a amavadina pode servir de modificador eficiente para a detecção eletroanalítica da ergina. Outrossim, a presença de um material orgânico no modificador reforça a capacidade da ergina de polimerizar-se, formando um compósito polimérico. Resultados: Os comportamentos oscilatório e monotô-nico são mais prováveis que no caso mais comum, haja vista a formação-deformação de compostos iônicos aquando da detecção eletroanalítica.

SUMMARY Introduction: For the first time, the electroanalytical process of ergin (LSA) determination over an electrode, modified by triazolic derivative, doped by an amavadin-ion, has been theoretically described. Methods: The mathematical model, correspondent to the sensor function, has been developed and analyzed by means of linear stability theory. It has been shown that the amavadin may serve as an efficient electrode modifier for the electroanalytical detection of ergin. Moreover, the presence of an organic material as electrode modifier reinforces the possibility of ergin polymerization, yielding a polymer composite. Results: The oscillatory and monotonic behavior is more probable than in the common case, considering the formation and destruction of the ionic compounds during the electroanalytical detection.

RESUMEN Introducción: Por primera vez se ha descrito teóricamente el proceso eletroanalítico de detección de ergina (LSA) en un electrodo, modificado por un derivado triazólico, dopado por el ión amavadina. Métodos: El modelo matemático, correspondiente al rendimiento del sensor, ha sido desarrollado y analizado desde el punto de vista de la teoría de la estabilidad lineal. Se ha demostrado que la amavadina puede servir como un modificador eficaz para la detección eletroanalítica de ergina. Además, la presencia de un material orgánico en el modificador refuerza la capacidad de la ergina para polimerizar, formando un compuesto polimérico. Resultados: Los comportamientos oscilatorios y monótonos son más probables que en el caso más común, dada la formación-deformación de compuestos iónicos durante la detección eletroanalítica.

Descripción matemática de la determinación electroanalítica del fármaco salvarsano y su ciclooligómeros, asistida por un compuesto del colorante escuárico y oxihidróxido de cobalto / The mathematical description of the electroanalytical determination of salvarsan drug and its cyclooligomers, assisted by the composite of squaraine dye with cobalt oxyhydroxide / A descrição matemática da determinação eletroanalítica do fármaco salvarsan e seus ciclo-oligômeros, auxiliada pela composição do corante esquaraína com oxihidróxido de cobalto

RESUMEN Objetivo: En este trabajo se realiza, por primera vez, la evaluación teórica de la posibilidad de la detección electroanalítica de salvarsano, fármaco antisifilítico. El oxihidróxido de cobalto, en su compuesto con el colorante escuárico, se usa como modificador de electrodo. Metodología: Mediante el análisis de estabilidad, se ha confirmado su eficiencia en los procesos de detección de salvarsano. La linearidad de dependencia entre el parámetro electroquímico y la concentración del fármaco se obtiene y se mantiene fácilmente. Conclusión: Las inestabilidades oscilatoria y monotónica se realizan en el sistema, causadas por las influencias de las etapas electroquímicas a las capacitancias de la doble capa eléctrica (DCE).

SUMMARY Aim: In this work, the theoretical evaluation of the electroanalytical detection of antisyphilitic drug salvarsan is given for the first time. Cobalt oxyhydroxide in a composite with the squaraine dye is used as electrode modifier. Methodology: By means of the stability analysis the efficiency of the salvarsan determination is confirmed. The linearity of the dependence between the electrochemical parameter and drug concentration is easily obtained and maintained. Conclusion: The oscillatory and monotonic instabilities are realized in this system, being caused by the electrochemical stages' influences to the double electric layer (DEL).

RESUMO Objetivo: neste trabalho, a avaliação teórica da detecção eletroanalítica do antissifilítico salvarsan é feita pela primeira vez. O oxihidróxido de cobalto em um composto com o corante esquaraína é usado como modificador de eletrodo. Metodologia: por meio da análise de estabilidade é confirmada a eficiência da determinação de salvarsan. A linearidade da dependência entre o parâmetro eletroquímico e a concentração do fármaco é facilmente obtida e mantida. Conclusão: as instabilidades osci-latórias e monotônicas são percebidas neste sistema, sendo causadas pelas influências dos estágios eletroquímicos sobre a dupla camada elétrica (DEL).

Comparison of ASSR, ABR and 40 Hz AERP Response Thresholds at Different Frequencies and Their Forensic Applications / 法医学杂志

OBJECTIVES@#To explore the relationship between the frequency characteristics and response threshold of auditory steady-state response (ASSR), auditory brainstem response (ABR) and 40 Hz auditory event related potential (40 Hz AERP), and their application values in forensic medicine.@*METHODS@#Thirty volunteers with normal hearing (60 ears) were selected to perform pure tone audiometry (PTA) threshold and ASSR, ABR and 40 Hz AERP response threshold tests in the standard sound insulation shielding room, and the results were statistically analyzed by SPSS 22.0 software.@*RESULTS@#At 0.5 kHz and 1.0 kHz frequencies, the correlation between 40 Hz AERP response threshold and PTA threshold was good, which was better than that of ASSR and ABR response threshold. At 2.0 kHz and 4.0 kHz frequencies, the correlation between ASSR and ABR response thresholds and PTA threshold was good, which was better than that of 40 Hz AERP response threshold.@*CONCLUSIONS@#To evaluate the hearing at 0.5 kHz and 1.0 kHz frequencies, it is recommended to use 40 Hz AERP and ASSR to comprehensively assess the PTA threshold of the subjects. To evaluate the hearing at 2.0 kHz and 4.0 kHz frequencies, ABR and ASSR are recommended to assess the PTA threshold of subjects comprehensively. The combination of ASSR, ABR and 40 Hz AERP can improve the accuracy of hearing function evaluation.

Application of Magnetization-prepared True Fast Imaging with Steady-state Precession Sequence in Brain Tumor Enhancement / 中国医学科学院学报

Objective To evaluate the application of two-dimensional magnetization-prepared true fast imaging with steady-state precession(2D-MP-TrueFISP)sequence in brain tumor enhancement.Methods In this study,60 cases of brain tumor patients who underwent enhanced magnetic resonance imaging of brain were scanned with 2D-MP-TrueFISP/two-dimensional spoiled gradient-recalled echo(2D-SPGR)before and after enhancement.The scores of lesions on the images of 2D-MP-TrueFISP/2D-SPGR were compared.At the same level of 2D-SPGE and 2D-MP-TrueFISP,the signal intensities(SIs)of lesions,white matter,and cerebrospinal fluid were measured before and after enhancement,and the contrast ratios(CRs)of lesions were calculated.The CRs before and after 2D-SPGR/2D-MP-TrueFISP enhancement and those between 2D-SPGR and 2D-MP-TrueFISP after enhancement were compared.Results The scores of lesions after 2D-MP-TrueFISP/2D-SPGR T1WI enhancement were 9.0(9.0,9.0)and 7.0(6.0,7.0),respectively,with significant difference(

Research progress on non-steady state noise-induced hearing loss / 中华劳动卫生职业病杂志

Non-steady state noise has become the main type of workplace noise. Compared with steady state noise, non-steady state noise may cause more serious hearing loss. This paper reviews the new situation of occupational hearing loss caused by non-steady state noise exposure, the overview of international noise exposure assessment standards and new challenges, and the new evidence of non-steady state noise induced hearing loss, so as to provide the basis for the future research of non-steady state noise induced hearing loss.

Robotic arm control system based on augmented reality brain-computer interface and computer vision / 生物医学工程学杂志

Brain-computer interface (BCI) has great potential to replace lost upper limb function. Thus, there has been great interest in the development of BCI-controlled robotic arm. However, few studies have attempted to use noninvasive electroencephalography (EEG)-based BCI to achieve high-level control of a robotic arm. In this paper, a high-level control architecture combining augmented reality (AR) BCI and computer vision was designed to control a robotic arm for performing a pick and place task. A steady-state visual evoked potential (SSVEP)-based BCI paradigm was adopted to realize the BCI system. Microsoft's HoloLens was used to build an AR environment and served as the visual stimulator for eliciting SSVEPs. The proposed AR-BCI was used to select the objects that need to be operated by the robotic arm. The computer vision was responsible for providing the location, color and shape information of the objects. According to the outputs of the AR-BCI and computer vision, the robotic arm could autonomously pick the object and place it to specific location. Online results of 11 healthy subjects showed that the average classification accuracy of the proposed system was 91.41%. These results verified the feasibility of combing AR, BCI and computer vision to control a robotic arm, and are expected to provide new ideas for innovative robotic arm control approaches.