153 research outputs found
Antifungal and Antioxidant Activities of the Essential Oil from Angelica koreana
Purpose. The purpose of this study is to determine the antifungal and antioxidant activities of the essential oil from Angelica koreana. Methods. Essential oil was obtained from the dried roots of A. koreana by steam distillation, and its composition was identified by gas chromatography and mass spectrometry (GC-MS). The minimal inhibitory concentrations (MICs) of the oil fraction and its main components were determined by broth dilution assay using common pathogenic Aspergillus and Trichophyton species. The combined effects of the oils with itraconazole were evaluated using a checkerboard titer test. In addition, 1,1-diphenyl-2-picryl-hydrazil (DPPH) free radical scavenging, nitrite inhibition, and reducing power were determined to assess the antioxidant activity of this oil. Results. The essential oil fraction and its main components showed inhibitory activity against all of the tested fungi, with minimal inhibitory concentrations (MICs) of 250–1000 μg/mL. Furthermore, this oil exhibited synergism when combined with itraconazole. Conclusion. In the treatment of infections caused by Aspergillus and Trichophyton species, combining itraconazole with either A. koreana essential oil or its main components may reduce the minimum effective dose of itraconazole required and, thus, minimize its side effects. In addition, this oil is a promising source of natural antioxidant agents
Faraday instability on a sphere: numerical simulation
We consider a spherical variant of the Faraday problem, in which a spherical
drop is subjected to a time-periodic body force, as well as surface tension. We
use a full three-dimensional parallel front-tracking code to calculate the
interface motion of the parametrically forced oscillating viscous drop, as well
as the velocity field inside and outside the drop. Forcing frequencies are
chosen so as to excite spherical harmonic wavenumbers ranging from 1 to 6. We
excite gravity waves for wavenumbers 1 and 2 and observe translational and
oblate-prolate oscillation, respectively. For wavenumbers 3 to 6, we excite
capillary waves and observe patterns analogous to the Platonic solids. For low
viscosity, both subharmonic and harmonic responses are accessible. The patterns
arising in each case are interpreted in the context of the theory of pattern
formation with spherical symmetry
Duo: Software Defined Intrusion Tolerant System Using Dual Cluster
An intrusion tolerant system (ITS) is a network security system that is composed of redundant virtual servers that are online only in a short time window, called exposure time. The servers are periodically recovered to their clean state, and any infected servers are refreshed again, so attackers have insufficient time to succeed in breaking into the servers. However, there is a conflicting interest in determining exposure time, short for security and long for performance. In other words, the short exposure time can increase security but requires more servers to run in order to process requests in a timely manner. In this paper, we propose Duo, an ITS incorporated in SDN, which can reduce exposure time without consuming computing resources. In Duo, there are two types of servers: some servers with long exposure time (White server) and others with short exposure time (Gray server). Then, Duo classifies traffic into benign and suspicious with the help of SDN/NFV technology that also allows dynamically forwarding the classified traffic to White and Gray servers, respectively, based on the classification result. By reducing exposure time of a set of servers, Duo can decrease exposure time on average. We have implemented the prototype of Duo and evaluated its performance in a realistic environment
Multi-Robot Relative Pose Estimation in SE(2) with Observability Analysis: A Comparison of Extended Kalman Filtering and Robust Pose Graph Optimization
In this study, we address multi-robot localization issues, with a specific
focus on cooperative localization and observability analysis of relative pose
estimation. Cooperative localization involves enhancing each robot's
information through a communication network and message passing. If odometry
data from a target robot can be transmitted to the ego robot, observability of
their relative pose estimation can be achieved through range-only or
bearing-only measurements, provided both robots have non-zero linear
velocities. In cases where odometry data from a target robot are not directly
transmitted but estimated by the ego robot, both range and bearing measurements
are necessary to ensure observability of relative pose estimation. For
ROS/Gazebo simulations, we explore four sensing and communication structures.
We compare extended Kalman filtering (EKF) and pose graph optimization (PGO)
estimation using different robust loss functions (filtering and smoothing with
varying batch sizes of sliding windows) in terms of estimation accuracy. In
hardware experiments, two Turtlebot3 equipped with UWB modules are used for
real-world inter-robot relative pose estimation, applying both EKF and PGO and
comparing their performance.Comment: 20 pages, 21 figure
DRAINCLoG: Detecting Rogue Accounts with Illegally-obtained NFTs using Classifiers Learned on Graphs
As Non-Fungible Tokens (NFTs) continue to grow in popularity, NFT users have
become targets of phishing attacks by cybercriminals, called \textit{NFT
drainers}. Over the last year, \$100 million worth of NFTs were stolen by
drainers, and their presence remains a serious threat to the NFT trading space.
However, no work has yet comprehensively investigated the behaviors of drainers
in the NFT ecosystem.
In this paper, we present the first study on the trading behavior of NFT
drainers and introduce the first dedicated NFT drainer detection system. We
collect 127M NFT transaction data from the Ethereum blockchain and 1,135
drainer accounts from five sources for the year 2022. We find that drainers
exhibit significantly different transactional and social contexts from those of
regular users. With these insights, we design \textit{DRAINCLoG}, an automatic
drainer detection system utilizing Graph Neural Networks. This system
effectively captures the multifaceted web of interactions within the NFT space
through two distinct graphs: the NFT-User graph for transaction contexts and
the User graph for social contexts. Evaluations using real-world NFT
transaction data underscore the robustness and precision of our model.
Additionally, we analyze the security of \textit{DRAINCLoG} under a wide
variety of evasion attacks.Comment: To appear in NDSS 202
Wave equation calculation of most energetic traveltimes and amplitudes for Kirchhoff prestack migration
This work was conceived during a visit by Kurt Marfurt to
Seoul National University, sponsored by the Korean Ministry
of Science andTechnology.This work was financially supported
by the Brain Korea 21 Project of the Ministry of Education of
Korea and the National Research Laboratory project of the
Ministry of Science and Technology. The authors acknowledge
the support of the Korea Institute of Science and Technology
Information (KISTI) under the Grand Challenge Support Program
and the use of the Supercomputing Center
A Herbal Medicine, Gongjindan
This study protocol aims to explore the effectiveness, safety, and cost-effectiveness of a herbal medication, Gongjindan (GJD), in patients with chronic dizziness. This will be a prospective, multicenter, randomized, double-blind, placebo-controlled, parallel-group, clinical trial. Seventy-eight patients diagnosed with Meniere’s disease, psychogenic dizziness, or dizziness of unknown cause will be randomized and allocated to either a GJD or a placebo group in a 1 : 1 ratio. Participants will be orally given 3.75 g GJD or placebo in pill form once a day for 56 days. The primary outcome measure will be the Dizziness Handicap Inventory score. Secondary outcome measures will be as follows: severity (mean vertigo scale and visual analogue scale) and frequency of dizziness, balance function (Berg Balance Scale), fatigue (Fatigue Severity Scale) and deficiency pattern/syndrome (qi blood yin yang-deficiency questionnaire) levels, and depression (Korean version of Beck’s Depression Inventory) and anxiety (State-Trait Anxiety Inventory) levels. To assess safety, adverse events, including laboratory test results, will be monitored. Further, the incremental cost-effectiveness ratio will be calculated based on quality-adjusted life years (from the EuroQoL five dimensions’ questionnaire) and medical expenses. Data will be statistically analyzed at a significance level of 0.05 (two-sided). This trial is registered with ClinicalTrials.gov NCT03219515, in July 2017
Acupuncture for Spasticity after Stroke: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
The aim of this systematic review was to determine how effective acupuncture or electroacupuncture (acupuncture with electrical stimulation) is in treating poststroke patients with spasticity. We searched publications in Medline, EMBASE, and the Cochrane Library in English, 19 accredited journals in Korean, and the China Integrated Knowledge Resources Database in Chinese through to July 30, 2013. We included randomized controlled trials (RCTs) with no language restrictions that compared the effects of acupuncture or electroacupuncture with usual care or placebo acupuncture. The two investigators assessed the risk of bias and statistical analyses were performed. Three RCTs in English, 1 in Korean, and 1 in Chinese were included. Assessments were performed primarily with the Modified Ashworth Scale (MAS). Meta-analysis showed that acupuncture or electroacupuncture significantly decreased spasticity after stroke. A subgroup analysis showed that acupuncture significantly decreased wrist, knee, and elbow spasticity in poststroke patients. Heterogeneity could be explained by the differences in control, acupoints, and the duration after stroke occurrence. In conclusion, acupuncture could be effective in decreasing spasticity after stroke, but long-term studies are needed to determine the longevity of treatment effects
Changes in Body Water Caused by Sleep Deprivation in Taeeum and Soyang Types in Sasang Medicine: Prospective Intervention Study
Background. There is a negative relationship between sleep deprivation and health. However, no study has investigated the effect of sleep deprivation on individuals with different body composition. The aim of this study was to determine the differential effect of sleep deprivation in individuals with different body compositions (fluid) according to Soyang type (SY) and Taeeum type (TE). Methods. Sixty-two cognitively normal, middle-aged people with normal sleep patterns were recruited from the local population. The duration of participants’ sleep was restricted to 4 h/day during the intervention phase. To examine the physiological changes brought on by sleep deprivation and recovery, 10 ml of venous blood was obtained. Results. Total Body Water (TBW) and Extracellular Water (ECW) were significantly different between the groups in the intervention phase. Physiological parameters also varied from the beginning of the resting phase to the end of the experiment. Potassium levels changed more in SY than TE individuals. Conclusion. Participants responded differently to the same amount of sleep deprivation depending on their Sasang constitution types. This study indicated that SY individuals were more sensitive to sleep deprivation and were slower to recover from the effects of sleep deprivation than TE individuals
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