Brain-Switches for Asynchronous Brain−Computer Interfaces: A Systematic Review

A brain–computer interface (BCI) has been extensively studied to develop a novel communication system for disabled people using their brain activities. An asynchronous BCI system is more realistic and practical than a synchronous BCI system, in that, BCI commands can be generated whenever the user wants. However, the relatively low performance of an asynchronous BCI system is problematic because redundant BCI commands are required to correct false-positive operations. To significantly reduce the number of false-positive operations of an asynchronous BCI system, a two-step approach has been proposed using a brain-switch that first determines whether the user wants to use an asynchronous BCI system before the operation of the asynchronous BCI system. This study presents a systematic review of the state-of-the-art brain-switch techniques and future research directions. To this end, we reviewed brain-switch research articles published from 2000 to 2019 in terms of their (a) neuroimaging modality, (b) paradigm, (c) operation algorithm, and (d) performance

Reusable, polyethylene glycol-structured microfluidic channel for particle immunoassays

A microfluidic channel made entirely out of polyethylene glycol (PEG), not PEG coating to silicon or polydimethylsiloxane (PDMS) surface, was fabricated and tested for its reusability in particle immunoassays and passive protein fouling, at relatively high target concentrations (1 mg ml-1). The PEG devices were reusable up to ten times while the oxygen-plasma-treated polydimethyl siloxane (PDMS) device could be reused up to four times and plain PDMS were not reusable. Liquid was delivered spontaneously via capillary action and complicated bonding procedure was not necessary. The contact angle analysis revealed that the water contact angle on microchannel surface should be lower than ~60°, which are comparable to those on dried protein films, to be reusable for particle immunoassays and passive protein fouling

Chemically Exfoliated Graphene Nanosheets for Flexible Electrode Applications

Graphene oxide (GO), produced by oxidation of graphite powder and exfoliation, is intensively utilized in electrodes, templates for hybrid materials, interfacial modifiers, three-dimensional structures, and so on, with its performance as an electrode material being determined by its chemical and structural states. This chapter describes the fabrication method of GO nanosheets from graphite oxide powder and their stable dispersion after reduction and applications in devices. Rheologically driven exfoliation and unusual acoustic cavitation methods were applied to produce large and less defective GO nanosheets. As a dispersion strategy of reduced GO (RGO) in solution, TiO2 precursor, cation-π interaction, silanol groups were introduced. Moreover, supramolecular chemistry, for example, quadruple hydrogen bonding moieties, was applied to solve the dispersion of highly concentrated RGO pastes. As potential applications of GO and RGO, we described GO as a p-type dopant and interfacial modifier as well as energy storage electrodes, IR sensors, and emitters. The judicious use of chemically exfoliated graphene can open new applications as a flexible electrode

Comparative study on multibody vehicle dynamics models based on subsystem synthesis method using Cartesian and joint coordinates

AbstractThe subsystem synthesis method has been developed in order to improve computational efficiency for a multibody vehicle dynamics model. Using the subsystem synthesis method, equations of motion of the base body and each subsystem can be solved separately. In the subsystem synthesis method, various coordinate systems can be used and various integration methods can be applied in each subsystem, as long as the effective mass matrix and the effective force vector are properly produced. In this paper, comparative study has been carried out for the subsystem synthesis method with Cartesian coordinates and with joint relative coordinates. Two different integration methods such as an explicit integrator and an explicit implicit integrator are employed. In order to see the accuracy and computational efficiency from the different models based on the different coordinate systems and different integration methods, a rough terrain run simulations has been carried out with a 6 × 6 off-road multibody vehicle model

Clinical features of macrocephaly at birth in Korea

PurposeThis study aimed to investigate the clinical features of macrocephaly at birth in Korea using ultrasonography.MethodsWe retrospectively investigated the medical records of full-term birth neonates in Cheil General Hospital & Women's Healthcare Center from January 2000 to June 2012. The following parameters were recorded and analyzed: gestational age, sex, birth weight, height, occipitofrontal circumference (OFC), physical examination, perinatal problems, and ultrasonography results. Macrocephaly was diagnosed when the OFC was greater than two standard deviations, based on the 2007 Korean National Growth Charts.ResultsThere were 75 neonates with macrocephaly at birth (52 boys and 23 girls), with a mean OFC of 38.1±0.49 cm. A comparison of the birth weight and height with the OFC value showed that height was correlated with OFC (r=0.35) but birth weight was not correlated with OFC (r=0.06). There were no remarkable findings in 56 cases (75%). Germinal matrix hemorrhage was identified in 10 cases (13%). An enlarged cerebrospinal fluid space was found in 5 cases (6.7%). There were 3 cases of mega-cisterna magna (4%), 1 case of ventriculomegaly, and 1 case of an enlarged interhemispheric space (6 mm) among these patients. In addition, a choroid plexus cyst was seen in 1 case. Mineralizing vasculopathy in both basal ganglia with no evidence of congenital infection was found in 2 cases and an asymptomatic subarachnoid hemorrhage was found in 1 case.ConclusionOur results indicate that macrocephaly at birth has benign ultrasonography findings and shows a pattern of male dominance

The Formation and Differentiation of Modern Korean Music World

Translated from the article published in Culture and Society, vol. 10, 2011, with permission from the Korean Association for Sociology of CultureThis study examines the formation and characteristics of modern music world in colonial Korea during the 1930s. Modern Korean music world inherited the legacy of traditional Korean music, but at the same time was heavily influenced by the newly introduced western music and Japanese popular music. In analyzing the formation of music world, we focus on the dynamics between different musical genres and also on the relationships between composers and singers. Social Network Analysis of two-mode data on genre-singer, genrecomposer, and composer-singer networks reveals that boundaries between genres became more established over time and that the relationship between composers and singers show limited stability reflecting the high level of uncertainty in the market of popular music

Characterization of Mammalian Selenoprotein O: A Redox-Active Mitochondrial Protein

Selenoproteins exhibit diverse biological functions, most of which are associated with redox control. However, the functions of approximately half of mammalian selenoproteins are not known. One such protein is Selenoprotein O (SelO), the largest mammalian selenoprotein with orthologs found in a wide range of organisms, including bacteria and yeast. Here, we report characterization of mammalian SelO. Expression of this protein could be verified in HEK 293T cells by metabolic labeling of cells with 75Se, and it was abolished when selenocysteine was replaced with serine. A CxxU motif was identified in the C-terminal region of SelO. This protein was reversibly oxidized in a time- and concentration-dependent manner in HEK 293T cells when cells were treated with hydrogen peroxide. This treatment led to the formation of a transient 88 kDa SelO-containing complex. The formation of this complex was enhanced by replacing the CxxU motif with SxxC, but abolished when it was replaced with SxxS, suggesting a redox interaction of SelO with another protein through its Sec residue. SelO was localized to mitochondria and expressed across mouse tissues. Its expression was little affected by selenium deficiency, suggesting it has a high priority for selenium supply. Taken together, these results show that SelO is a redox-active mitochondrial selenoprotein