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1.
Nanoscale ; 12(3): 2142-2153, 2020 Jan 23.
Article in English | MEDLINE | ID: mdl-31913395

ABSTRACT

Hierarchical structured materials constructed with conductive carbon materials have been extensively studied as S host materials for Li-S batteries. However, their outwardly developed hierarchical structures, which do not contain structures or materials to inhibit polysulfide dissolution, lead to the dissipation of dissolved polysulfides and poor dispersion properties during the slurry-making process, which results in non-uniformity in the cathodes. Herein, an assembly of polar materials (hollow structured SiO2 microspheres) and electrically conductive hierarchical N-doped bamboo-like carbon nanotubes (b-NCNTs) is designed as an efficient S host material for minimizing the dissolution of polysulfides during Li-S battery operations. Highly aligned and packed b-NCNTs are grown in hollow structured SiO2 microspheres. The SiO2 layer coated on the surface of the hollow CoFe2O4 microspheres plays a key role in the synthesis of easily dispersible hierarchical b-NCNTs microspheres (b-NCNTs@SiO2). The S-loaded b-NCNTs@SiO2 electrodes show better cycling stability than S-loaded b-NCNTs electrodes. The polysulfide trapping of the polar SiO2 layer and the well-developed b-NCNTs minimize the dissolution of polysulfides during cycling. In addition, the introduction of electronegative N atoms into the b-NCNTs lattice enhances their polysulfide trapping ability. The S-loaded b-NCNTs@SiO2 electrodes exhibit stable discharge capacities of >771 mA h g-1 over 195 cycles at a current density of 0.5 C and a high reversible capacity of 486 mA h g-1 even at a high current density of 5.0 C.

2.
Small ; 15(24): e1901320, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31058450

ABSTRACT

Multicomponent materials with various double cations have been studied as anode materials of lithium-ion batteries (LIBs). Heterostructures formed by coupling different-bandgap nanocrystals enhance the surface reaction kinetics and facilitate charge transport because of the internal electric field at the heterointerface. Accordingly, metal selenites can be considered efficient anode materials of LIBs because they transform into metal selenide and oxide nanocrystals in the first cycle. However, few studies have reported synthesis of uniquely structured metal selenite microspheres. Herein, synthesis of high-porosity CoSeO3 microspheres is reported. Through one-pot oxidation at 400 °C, CoSex -C microspheres formed by spray pyrolysis transform into CoSeO3 microspheres showing unordinary cycling and rate performances. The conversion mechanism of CoSeO3 microspheres for lithium-ion storage is systematically studied by cyclic voltammetry, in situ X-ray diffraction and electrochemical impedance spectroscopy, and transmission electron microscopy. The reversible reaction mechanism of the CoSeO3 phase from the second cycle onward is evaluated as CoO + xSeO2 + (1 - x)Se + 4(x + 1)Li+ + 4( x + 1)e- ↔ Co + (2x + 1)Li2 O + Li2 Se. The CoSeO3 microspheres show a high reversible capacity of 709 mA h g-1 for the 1400th cycle at a current density of 3 A g-1 and a high reversible capacity of 526 mA h g-1 even at an extremely high current density of 30 A g-1 .

3.
PLoS One ; 14(4): e0213140, 2019.
Article in English | MEDLINE | ID: mdl-30943195

ABSTRACT

Depressive symptoms are related to abnormalities in the autonomic nervous system (ANS), and physiological signals that can be used to measure and evaluate such abnormalities have previously been used as indicators for diagnosing mental disorder, such as major depressive disorder (MDD). In this study, we investigate the feasibility of developing an objective measure of depressive symptoms that is based on examining physiological abnormalities in individuals when they are experiencing mental stress. To perform this, we recruited 30 patients with MDD and 31 healthy controls. Then, skin conductance (SC) was measured during five 5-min experimental phases, comprising baseline, mental stress, recovery from the stress, relaxation, and recovery from the relaxation, respectively. For each phase, the mean amplitude of the skin conductance level (MSCL), standard deviations of the SCL (SDSCL), slope of the SCL (SSCL), mean amplitude of the non-specific skin conductance responses (MSCR), number of non-specific skin conductance responses (NSCR), and power spectral density (PSD) were evaluated from the SC signals, producing 30 parameters overall (six features for each phase). These features were used as input data for a support vector machine (SVM) algorithm designed to distinguish MDD patients from healthy controls based on their physiological responses. Statistical tests showed that the main effect of task was significant in all SC features, and the main effect of group was significant in MSCL, SDSCL, SSCL, and PSD. In addition, the proposed algorithm achieved 70% accuracy, 70% sensitivity, 71% specificity, 70% positive predictive value, 71% negative predictive value in classifying MDD patients and healthy controls. These results demonstrated that it is possible to extract meaningful features that reflect changes in ANS responses to various stimuli. Using these features, detection of MDD was feasible, suggesting that SC analysis has great potential for future diagnostics and prediction of depression based on objective interpretation of depressive states.


Subject(s)
Autonomic Nervous System/physiopathology , Depressive Disorder, Major/diagnosis , Galvanic Skin Response/physiology , Stress, Psychological/physiopathology , Adult , Aged , Case-Control Studies , Depressive Disorder, Major/physiopathology , Depressive Disorder, Major/psychology , Feasibility Studies , Female , Healthy Volunteers , Humans , Male , Mathematical Concepts , Middle Aged , Sensitivity and Specificity , Skin/innervation , Stress, Psychological/psychology , Young Adult
4.
Small ; 15(2): e1803043, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30484957

ABSTRACT

In this work, a facile salt-templated approach is developed for the preparation of hollow FeSe2 /graphitic carbon composite microspheres as sodium-ion battery anodes; these are composed of interconnected multicavities and an enclosed surface in-plane embedded with uniform hollow FeSe2 nanoparticles. As the precursor, Fe2 O3 /carbon microspheres containing NaCl nanocrystals are obtained using one-pot ultrasonic spray pyrolysis in which inexpensive NaCl and dextrin are used as a porogen and carbon source, respectively, enabling mass production of the composites. During post-treatment, Fe2 O3 nanoparticles in the composites transform into hollow FeSe2 nanospheres via the Kirkendall effect. These rational structures provide numerous conductive channels to facilitate ion/electron transport and enhance the capacitive contribution. Moreover, the synergistic effect between the hollow cavities within FeSe2 and the outstanding mechanical strength of the porous carbon matrix can effectively accommodate the large volume changes during cycling. Correspondingly, the composite microsphere exhibits high discharge capacity of 510 mA h g-1 after 200 cycles at 0.2 A g-1 with capacity retention of 88% when calculated from the second cycle. Even at a high current density of 5.0 A g-1 , a high discharge capacity of 417 mA h g-1 can be achieved.

5.
Toxicol Res ; 29(4): 263-78, 2013 Dec 31.
Article in English | MEDLINE | ID: mdl-24578797

ABSTRACT

The silkworm extract powder contain 1-deoxynojirimycin (DNJ), a potent α-glycosidase inhibitor, has therapeutic potency against diabetes mellitus. Therefore, natural products containing DNJ from mulberry leaves and silkworm are consumed as health functional food. The present study was performed to evaluate the safety of the silkworm extract powder, a health food which containing the DNJ. The repeated toxicity studies and gentic toxicity studies of the silkworm extract powder were performed to obtain the data for new functional food approval in MFDS. The safety was evaluated by a single-dose oral toxicity study and a 90 day repeated-dose oral toxicity study in Sprague-Dawley rats. The silkworm extract powder was also evaluated for its mutagenic potential in a battery of genetic toxicity test: in vitro bacterial reverse mutation assay, in vitro chromosomal aberration test, and in vivo mouse bone marrow micronucleus assay. The results of the genetic toxicology assays were negative in all of the assays. The approximate lethal dose in single oral dose toxicity study was considered to be higher than 5000 mg/kg in rats. In the 90 day study, the dose levels were wet at 0, 500, 1000, 2000 mg/kg/day, and 10 animals/sex/dose were treated with oral gavage. The parameters that were monitored were clinical signs, body weights, food and water consumptions, ophthalmic examination, urinalysis, hematology, serum biochemistry, necropsy findings, organ weights, and histopathological examination. No adverse effects were observed after the 90 day administration of the silkworm extract powder. The No-Observed-Adverse-Effect-Level (NOAEL) of silkworm extract powder in the 90 day study was 2000 mg/kg/day in both sexes, and no target organ was identified.

6.
Eur J Med Chem ; 46(8): 3201-9, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21601964

ABSTRACT

Designed and synthesized were a series of 5H-chromeno[4,3-b]pyridines with substitution at 2- and 4-positions with various 5- or 6-membered heteroaromatics as antitumor agents. They were evaluated for topoisomerase I and II inhibitory activities as well as cytotoxicities against several human cancer cell lines. Structure-activity relationship study showed that 2-furyl or 2-thienyl at 2- or 4-position of central pyridine is crucial in displaying topo I or II inhibitory activity and cytotoxicity.


Subject(s)
Antigens, Neoplasm/metabolism , Benzopyrans/chemical synthesis , Cell Proliferation/drug effects , DNA Topoisomerases, Type II/metabolism , DNA Topoisomerases, Type I/metabolism , DNA-Binding Proteins/metabolism , Neoplasms/enzymology , Pyridines/chemical synthesis , Topoisomerase I Inhibitors/chemical synthesis , Topoisomerase II Inhibitors/chemical synthesis , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Benzopyrans/pharmacology , Cell Line, Tumor , Drug Screening Assays, Antitumor , Female , Humans , Male , Neoplasms/drug therapy , Neoplasms/pathology , Pyridines/pharmacology , Structure-Activity Relationship , Topoisomerase I Inhibitors/pharmacology , Topoisomerase II Inhibitors/pharmacology
7.
Bioorg Med Chem ; 18(6): 2245-2254, 2010 Mar 15.
Article in English | MEDLINE | ID: mdl-20188578

ABSTRACT

A series of 2-(thienyl-2-yl or -3-yl)-4-furyl-6-aryl pyridine derivatives were designed, synthesized, and evaluated for their topoisomerase I and II inhibition and cytotoxic activity against several human cancer cell lines. Compounds 10-19 showed moderate topoisomerase I and II inhibitory activity and 20-29 showed significant topoisomerase II inhibitory activity. Structure-activity relationship study revealed that 4-(5-chlorofuran-2-yl)-2-(thiophen-3-yl) moiety has an important role in displaying topoisomerase II inhibition.


Subject(s)
Antineoplastic Agents/pharmacology , Enzyme Inhibitors/pharmacology , Pyridines/pharmacology , Topoisomerase I Inhibitors , Topoisomerase II Inhibitors , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Proliferation/drug effects , DNA Topoisomerases, Type I/chemistry , DNA Topoisomerases, Type I/metabolism , DNA Topoisomerases, Type II/chemistry , DNA Topoisomerases, Type II/metabolism , Drug Design , Drug Screening Assays, Antitumor , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Humans , Molecular Structure , Pyridines/chemical synthesis , Pyridines/chemistry , Stereoisomerism , Structure-Activity Relationship , Tumor Cells, Cultured
8.
Bioorg Med Chem Lett ; 20(1): 42-7, 2010 Jan 01.
Article in English | MEDLINE | ID: mdl-19954977

ABSTRACT

For the development of novel antitumor agents, 2,6-dithienyl-4-furyl pyridine derivatives were prepared and evaluated for their topoisomerase I and II inhibitory activity as well as cytotoxicity against several human cancer cell lines. Among the 21 prepared compounds, compound 24 exhibited strong topoisomerase I inhibitory activity. In addition, a docking study with topoisomerase I and compound 24 was performed.


Subject(s)
Antineoplastic Agents/chemistry , DNA Topoisomerases, Type II/metabolism , DNA Topoisomerases, Type I/metabolism , Pyridines/chemistry , Thiophenes/chemical synthesis , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/toxicity , Binding Sites , Cell Line, Tumor , Computer Simulation , Drug Screening Assays, Antitumor , Humans , Pyridines/chemical synthesis , Pyridines/toxicity , Structure-Activity Relationship , Thiophenes/chemistry , Thiophenes/toxicity , Topoisomerase I Inhibitors , Topoisomerase II Inhibitors
9.
Article in English | MEDLINE | ID: mdl-19964115

ABSTRACT

Medication adherence is important to patients who suffer from chronic disease. Regular medication activity reduces the cost of caring disease and prohibits the worsening of disease condition. To support patients taking medicine correctly, we developed a medication assistance system which alarms medication situation through multimedia messages and help patients to take a medicine. To enable the system copes with various situations related to a medication service, we designed a medication context model and implemented a state based context aware application. We also applied our system to patients and saw a little improvement in medication adherence.


Subject(s)
Medication Adherence , Models, Theoretical , Software Design , Age Distribution , Female , Health Plan Implementation , Humans , Male , Sex Characteristics
10.
Article in English | MEDLINE | ID: mdl-19163869

ABSTRACT

In this paper, we developed a system that could assist appropriate activities for medication adherence of the elderly. It employs a proactive knowledge which is represented as templates predefined for their medication activities. The knowledge-based assistance depends on the contexts considerably, which the system can recognize by continuously monitoring the current position and the time-schedule for their medications. The monitoring is performed with ultrasonic sensors and infrared sensors mounted in a display and a pillbox mainly. According to the recognized contexts, the medication activities can he serviced through old person-friendly multimedia display. In special, since the knowledge is well-defined by XML, only its content modification can provide a variety of services individually customized to the elderly.


Subject(s)
Drug Administration Schedule , Drug Therapy, Computer-Assisted/methods , Health Services for the Aged , Monitoring, Ambulatory/methods , Patient Compliance , Reminder Systems , User-Computer Interface , Aged , Aged, 80 and over , Humans , Korea
11.
Article in English | MEDLINE | ID: mdl-19162941

ABSTRACT

This paper suggests the method of correcting distance between an ambient intelligence display and a user based on linear regression and smoothing method, by which distance information of a user who approaches to the display can he accurately output even in an unanticipated condition using a passive infrared VIR) sensor and an ultrasonic device. The developed system consists of an ambient intelligence display and an ultrasonic transmitter, and a sensor gateway. Each module communicates with each other through RF (Radio frequency) communication. The ambient intelligence display includes an ultrasonic receiver and a PIR sensor for motion detection. In particular, this system selects and processes algorithms such as smoothing or linear regression for current input data processing dynamically through judgment process that is determined using the previous reliable data stored in a queue. In addition, we implemented GUI software with JAVA for real time location tracking and an ambient intelligence display.


Subject(s)
Artificial Intelligence , Telemetry/instrumentation , Algorithms , Linear Models , Software , Telemetry/methods , Ultrasonics , Video Recording/instrumentation , Video Recording/methods
12.
Article in English | MEDLINE | ID: mdl-18001974

ABSTRACT

In this paper, we propose a semantic inheritance/inverse-inheritance mechanism for systematic bio-ontology construction. This mechanism allows domain experts to easily manage sophisticated bio-ontologies in which biological knowledge is encoded; it automatically captures semantics inferred from the ontology structure being constructed or already constructed. Based on the captured semantics it suggests appropriate recommendation to the experts. While inheritance enables them to consistently determine the semantics of relationships between ontology concepts (or classes), inverse-inheritance allows them to incrementally refine the semantics by exploiting a huge amount of relationships between the instances of the concepts. To demonstrate the feasibility of the mechanism, we also implement an OWL(Web Ontology Language)-based graphical bio-ontology management system. In the system, the mechanism is seamlessly applied to the ontology by well defined graphic notations based on OWL. OWL is adopted to fully express the subtle semantics inherently buried in the bio-ontology.


Subject(s)
Computational Biology/methods , DNA/genetics , Databases, Genetic , Hypermedia , Proteins/genetics , Internet , Plasmids/genetics
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