RESUMO
The recent development of closed-loop EEG phase-triggered transcranial magnetic stimulation (TMS) has advanced potential applications of adaptive neuromodulation based on the current brain state. Closed-loop TMS involves instantaneous acquisition of the EEG rhythm, timing prediction of the target phase, and triggering of TMS. However, the accuracy of EEG phase prediction algorithms is largely influenced by the system's transport delay, and their relationship is rarely considered in related work. This paper proposes a delay analysis that considers the delay of the closed-loop EEG phase-triggered TMS system as a primary factor in the validation of phase prediction algorithms. An in-silico validation using real EEG data was performed to compare the performance of commonly used algorithms. The experimental results indicate a significant influence of the total delay on the algorithm performance, and the performance ranking among algorithms varies at different levels of delay. We conclude that the delay analysis framework should be widely adopted in the design and validation of phase prediction algorithms for closed-loop EEG phase-triggered TMS systems.
Assuntos
Eletroencefalografia , Estimulação Magnética Transcraniana , Estimulação Magnética Transcraniana/métodos , Eletroencefalografia/métodos , Encéfalo/fisiologia , AlgoritmosRESUMO
The absorption of CO2 from CO2-N2 gas mixtures using water and monoethanolamine (MEA) solution in polypropylene (PP) hollow-fiber membrane contactors was experimentally and theoretically examined. Gas was flowed through the lumen of the module, whereas the absorbent liquid was passed counter-currently across the shell. Experiments were carried out under various gas- and liquid-phase velocities as well as MEA concentrations. The effect of pressure difference between the gas and liquid phases on the flux of CO2 absorption in the range of 15-85 kPa was also investigated. A simplified mass balance model that considers non-wetting mode as well as adopts the overall mass-transfer coefficient evaluated from absorption experiments was proposed to follow the present physical and chemical absorption processes. This simplified model allowed us to predict the effective length of the fiber for CO2 absorption, which is crucial in selecting and designing membrane contactors for this purpose. Finally, the significance of membrane wetting could be highlighted by this model while using high concentrations of MEA in the chemical absorption process.
RESUMO
Tantalum is a critical metal that is widely used in electronic products. The demand for tantalum is increasing, but the supply is limited. As tantalum waste products have increased in Taiwan in recent years, the treatment of spent tantalum capacitors has become necessary and important. The recycling of tantalum from tantalum capacitors will not only decrease pollution from waste, but will also conserve tantalum resources. The tantalum content in epoxy-coated solid electrolyte tantalum capacitors (EcSETCs) is over 40 wt.%. Here, we designed a recycling process that includes pre-treatment, leaching, and solvent extraction to recover tantalum. In the pre-treatment process, epoxy resin and wires were removed. During hydrometallurgical process, pressure leaching by hydrofluoric acid was used to leach tantalum and manganese from solid electrolyte tantalum capacitors (SETCs). During our testing of this proposed process, the acid concentration, reaction time, temperature, and solid-liquid ratio were examined for leaching. After the leaching process, Alamine 336 was used to extract tantalum from the leaching solution. The pH value, extractant concentration, extraction time, and aqueous-organic ratio were investigated. Then, tantalum was stripped using HNO3, and the HNO3 concentration, stripping time, and organic-aqueous ratio were analyzed in detail. Under optimal conditions, the recovery efficiency of tantalum reached over 98%, and a final product of tantalum pentoxide with 99.9% purity was obtained after chemical precipitation and calcination.
RESUMO
Objective To introduce a practical high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)method for the detection of seven growth hormone-releasing peptides (GHRPs)including GHRP-1,GHRP-2,GHRP-4,GHRP-5,GHRP-6,Hexarelin and Alexamorelin and two growth hormone secretagogues(GHS)including anamorelin and ipamorelin,and study the stability of these nine substances in the human urine.Method The urine samples were purified and extracted by a solid phase extraction procedure using Oasis(R) WCX column.The urine was first centrifuged and taken out 1 mL into a small column,cleaned by 5% NH4OH and 20% CH3CN respectively,eluated using the mixture of water and acetomitrile(1/3)with 2% formic acid,blow-dried in the nitrogen at 35℃ and finally redissolved to be injected into the LC-MS/MS.Result The limits of detection were between 0.01~0.5 ng/mL accordingly.The spiked recoveries at the low concentration(1 ng/mL),medium concentration(2 ng/mL)and high concentration(10 ng/mL)ranged between 40% and 76%.The intra-and interday precisions of the target substances at these three concentrations were all less than 15%.The indoor temperature,refrigeration condition and multigelation were observed to have significant impact on the anamorelin,GHRP-2,GHRP-4 and GHRP-5.Conclusion The method established in this study is simple,and its specificity and sensitivity meets the international standard and technical documents for laboratories set up by the Wworld Anti-Doping Agency.It has been applied in our routine work.Multigelation should be avoided in the transport,detection and long-term laboratory storage of urine samples.
RESUMO
We report an Nd:YAG laser pumped by light emission diodes (LEDs) at 750 nm. With 1% output coupling from a linear cavity containing a 2-cm long Nd:YAG crystal, the laser generated 37.5 µJ pulse energy at 1064 nm with M2 = 1.1 when pumped by 2.73-mJ LED energy in a 1-ms pulse at a 10 Hz rate. The measured optical and slope efficiencies for this linear-cavity laser are 1.36, and 9%, respectively. With 1 and 5% output couplings from a Z-cavity containing the same laser crystal, the lasers generated 346 and 288 µJ pulse energy with an optical efficiency of 3.4 and 2.8% and slope efficiency of 6.6 and 14%, respectively, for the same 1-ms pump pulse repeating at a 10 Hz rate. At the highest output from the Z-cavity, the measured M2 for the beam is 3.6.
RESUMO
Objective To investigate whether there existed a healthy obese subtype.Methods A total of 116 healthy subjects were recruited.They were divided into 3 groups according to BMI and metabolic disorders:40 cases of normal weight and metabolic normality (NMN),36 cases of obesity and metabolic normality (OMN) and 40 cases of obesity and metabolic abnormality (OMA).Anthropometic parameters as height,weight,waist circumference,hip circumference and blood pressure was recorded.Blood glucose,lipids,insulin,high-sensitivity C-reactive protein (hs-CRP) was detected.Body fat distribution was detected by dual-energy X-ray absorptiometry (DXA).Serum von Willebrand factor (vWF),a marker of endothelial dysfunction,were detected by ELISA.Results Both serum vWF levels in OMN group [(733.6±86.2)U/L] and OMA group[(809.2 ±46.3)U/L] are higher than that in NMN group [(466.9 ±65.3)U/L,P <0.05] with serum vWF level in OMA group is higher than in OMN group (P < 0.05).Among android fat mass percentage (AFM%),BMI,waist height ratio,waist circumference,hs-CRP,weight,hip circumference and trunk fat mass,AFM%,BMI and hs-CRP are main influencing factors of vWF.Conclusions Endothelial dysfunction existed in obese adults regardless of their metabolic status.There is no healthy obese subtype.AFM%,BMI and hs-CRP are the main influencing factors of endothelial dysfunction.
RESUMO
This work presents a novel star-ring-bus sensor system and demonstrates its effectiveness. The main trunk of the proposed sensor system is a star topology and the sensing branches comprise a series of bus subnets. Any weakness in the reliability of the sensor system is overcome by adding remote nodes and switches to the ring and bus subnets. To construct the proposed star-ring-bus sensor system, a fiber ring laser scheme is used to improve the signal-to-noise ratio of the sensor system. The proposed system increases the reliability and capacity of fiber sensor systems.
RESUMO
OBJECTIVE: To study the mutual interaction of vestibular afferent nervous system and vestibular efferent nervous system in vestibular compensation. METHODS: Build up animal model of vestibular compensation by destroying single side vestibule of wistar rat. In the study the rats were divided into 3 groups: Group A 16 normal rats; Group B 15 rats, after 7 days of left vestibular damage; Group C 7 rats 3 months after left vestibular damage; and Group D 7 rats, after vestibular compensation. Electromyography of the rats was recorded and the expression of calcitonin gene relative peptide (CGRP), choline acetyltransferase (AChT) and Na-K-ATPase were investigated in efferent vestibular nervous system. RESULTS: Electric potential activity of muscles of injury side decreased while that of the opposite side increased. In animals of vestibular compensation electric potential of bilateral musculus longus capitis at quiescent stage recovered symmetrically. CGRP positive cells of efferent vestibular nervous system increased bilaterally, and their activity enhanced, especially obvious at the acute stage. AChT positive cells of injury side of efferent vestibular nervous system decreased, but reaction degree of two sides enhanced. Reaction degree of the opposite side enhanced obviously at the stage of vestibular compensation. Expression of Na-K-ATPase mRNA of the same side was lower, but vestibular signal of the opposite side enhanced, clinically head and neck inclined obliquely by means of medial fasciculus of tractus vestibulospinalis. Months later, vestibular signal of the same side enhanced, and that of the opposite side enhanced also, clinical symptoms improved slightly. At the vestibular compensation stage, expression of Na-K-ATPase mRNA of the same side enhanced, and it was same as that of the opposite side or much higher, clinically it reached vestibular compensation. CONCLUSION: Comprehensive effect of the above results maybe as follows: Efferent vestibular nervous system inhibited afferent signal of the opposite vestibule, and it modulated excitement of vestibular center of the same side, and it worked in the complicated mechanisms of vestibular compensation. CGRP may have facilitation function to the vestibular afferent signal of injury side. While Ach improved vestibule compensation by means of inhibition of vestibule excitement of the healthy side.
Assuntos
Vias Aferentes/metabolismo , Vias Eferentes/metabolismo , Nervo Vestibular/metabolismo , Vestíbulo do Labirinto/metabolismo , Animais , Masculino , Ratos , Ratos Wistar , ATPase Trocadora de Sódio-Potássio/metabolismoRESUMO
<p><b>OBJECTIVE</b>To study the mutual interaction of vestibular afferent nervous system and vestibular efferent nervous system in vestibular compensation.</p><p><b>METHODS</b>Build up animal model of vestibular compensation by destroying single side vestibule of wistar rat. In the study the rats were divided into 3 groups: Group A 16 normal rats; Group B 15 rats, after 7 days of left vestibular damage; Group C 7 rats 3 months after left vestibular damage; and Group D 7 rats, after vestibular compensation. Electromyography of the rats was recorded and the expression of calcitonin gene relative peptide (CGRP), choline acetyltransferase (AChT) and Na-K-ATPase were investigated in efferent vestibular nervous system.</p><p><b>RESULTS</b>Electric potential activity of muscles of injury side decreased while that of the opposite side increased. In animals of vestibular compensation electric potential of bilateral musculus longus capitis at quiescent stage recovered symmetrically. CGRP positive cells of efferent vestibular nervous system increased bilaterally, and their activity enhanced, especially obvious at the acute stage. AChT positive cells of injury side of efferent vestibular nervous system decreased, but reaction degree of two sides enhanced. Reaction degree of the opposite side enhanced obviously at the stage of vestibular compensation. Expression of Na-K-ATPase mRNA of the same side was lower, but vestibular signal of the opposite side enhanced, clinically head and neck inclined obliquely by means of medial fasciculus of tractus vestibulospinalis. Months later, vestibular signal of the same side enhanced, and that of the opposite side enhanced also, clinical symptoms improved slightly. At the vestibular compensation stage, expression of Na-K-ATPase mRNA of the same side enhanced, and it was same as that of the opposite side or much higher, clinically it reached vestibular compensation.</p><p><b>CONCLUSION</b>Comprehensive effect of the above results maybe as follows: Efferent vestibular nervous system inhibited afferent signal of the opposite vestibule, and it modulated excitement of vestibular center of the same side, and it worked in the complicated mechanisms of vestibular compensation. CGRP may have facilitation function to the vestibular afferent signal of injury side. While Ach improved vestibule compensation by means of inhibition of vestibule excitement of the healthy side.</p>
Assuntos
Animais , Masculino , Ratos , Vias Aferentes , Metabolismo , Vias Eferentes , Metabolismo , Ratos Wistar , ATPase Trocadora de Sódio-Potássio , Metabolismo , Nervo Vestibular , Metabolismo , Vestíbulo do Labirinto , MetabolismoRESUMO
BACKGROUND: Apoptosis has been implicated in neuronal degeneration after optic and sciatic nerve injury. The mechanisms contributing to facial motoneuron death are poorly understood. This study investigated the mechanisms underlying facial motoneuronal death and the expression of BCL-2 in facial motoneurons after facial nerve injury. METHODS: Morphologic changes in the facial motoneurons were examined by light and transmission electron microscopy, and TdT-mediated dUTP-biotin nick end labeling (TUNEL) methods was used. Expression of BCL-2 was studied by immunohistochemistry and in situ hybridization after facial nerve injury. RESULTS: Cell shrinkage, condensed cytoplasm, and apoptotic bodies were demonstrated in numerous cells under light microscopy. The chromatin was condensed and localized to the nuclear envelope, forming a crescent or cap, and the endoplasmic reticulum was still visible but appeared swollen under electron microscopy. In vivo TUNEL staining displayed positive facial motoneurons 7 days after facial nerve transsection. The BCL-2 expression in facial motoneurons declined and reached its lowest level on the fifteenth day (p < 0.05). The reduction in BCL-2 expression after facial nerve transsection close to the facial motoneuron nucleus was greater than that of facial nerve transsection far away from the facial motoneuron nucleus (p < 0.05). BCL-2 expression after crushing of the facial nerve was found to be more intense in comparison with that after nerve transsection at the stylomastoid foramen (p < 0.05). CONCLUSIONS: These findings indicated that motoneuron death induced by facial nerve transsection was consistent with the process of apoptosis. The endogenous BCL-2 in these motoneurons may protect facial motoneurons from axotomy-induced cell death.