219 research outputs found

    Redirected Walking in Infinite Virtual Indoor Environment Using Change-blindness

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    We present a change-blindness based redirected walking algorithm that allows a user to explore on foot a virtual indoor environment consisting of an infinite number of rooms while at the same time ensuring collision-free walking for the user in real space. This method uses change blindness to scale and translate the room without the user's awareness by moving the wall while the user is not looking. Consequently, the virtual room containing the current user always exists in the valid real space. We measured the detection threshold for whether the user recognizes the movement of the wall outside the field of view. Then, we used the measured detection threshold to determine the amount of changing the dimension of the room by moving that wall. We conducted a live-user experiment to navigate the same virtual environment using the proposed method and other existing methods. As a result, users reported higher usability, presence, and immersion when using the proposed method while showing reduced motion sickness compared to other methods. Hence, our approach can be used to implement applications to allow users to explore an infinitely large virtual indoor environment such as virtual museum and virtual model house while simultaneously walking in a small real space, giving users a more realistic experience.Comment: https://www.youtube.com/watch?v=s-ZKavhXxd

    Consecutive Macular Edema and Visual Outcome in Branch Retinal Vein Occlusion

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    Purposes. The study introduced the concept of “consecutive macular edema” and evaluated the validity of visual outcome in macular edema (ME) secondary to branch retinal vein occlusion (BRVO). Methods. Patients were categorized into the gainer group and the nongainer group according to the final visual acuity. We analyzed clinical characteristics involving total and consecutive duration of ME between the two groups. Results. Among the total 71 eyes of 71 patients, intravitreal bevacizumab injection (26 patients), triamcinolone (21), and natural course (33) were enrolled. The consecutive duration of ME was shorter in the gainer group than in the nongainer group (3.33 ± 1.50 and 5.24 ± 2.39 months; P=0.000). After exclusion of macular ischemia, consecutive duration of ME in gainer group was also significantly shorter than in nongainer group (3.62 ± 1.60 and 6.11 ± 4.20 months; P=0.010). Conclusions. The duration of ME in the nongainer group was longer than in the gainer group. In particular, the consecutive duration was an important factor in determining the final visual outcome. Clinical Trial Registration. Approval by Hallym University Sacred Heart Hospital Institutional Review Board/Ethics Committee was obtained for this retrospective study

    Evaluation of the transporter-mediated herb-drug interaction potential of DA-9801, a standardized dioscorea extract for diabetic neuropathy, in human in vitro and rat in vivo

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    BACKGROUND: Drug transporters play important roles in the absorption, distribution, and elimination of drugs and thereby, modulate drug efficacy and toxicity. With a growing use of poly pharmacy, concurrent administration of herbal extracts that modulate transporter activities with drugs can cause serious adverse reactions. Therefore, prediction and evaluation of drug-drug interaction potential is important in the clinic and in the drug development process. DA-9801, comprising a mixed extract of Dioscoreae rhizoma and Dioscorea nipponica Makino, is a new standardized extract currently being evaluated for diabetic peripheral neuropathy in a phase II clinical study. METHOD: The inhibitory effects of DA-9801 on the transport functions of organic cation transporter (OCT)1, OCT2, organic anion transporter (OAT)1, OAT3, organic anion transporting polypeptide (OATP)1B1, OATP1B3, P-glycoprotein (P-gp), and breast cancer resistance protein (BCRP) were investigated in HEK293 or LLC-PK1 cells. The effects of DA-9801 on the pharmacokinetics of relevant substrate drugs of these transporters were also examined in vivo in rats. RESULTS: DA-9801 inhibited the in vitro transport activities of OCT1, OCT2, OAT3, and OATP1B1, with IC(50) values of 106, 174, 48.1, and 273 μg/mL, respectively, while the other transporters were not inhibited by 300 μg/mL DA-9801. To investigate whether this inhibitory effect of DA-9801 on OCT1, OCT2, and OAT3 could change the pharmacokinetics of their substrates in vivo, we measured the pharmacokinetics of cimetidine, a substrate for OCT1, OCT2, and OAT3, and of furosemide, a substrate for OAT1 and OAT3, by co-administration of DA-9801 at a single oral dose of 1,000 mg/kg. Pre-dose of DA-9801 5 min or 2 h prior to cimetidine administration decreased the C(max) of cimetidine in rats. However, DA-9801 did not affect the elimination parameters such as half-life, clearance, or amount excreted in the urine, suggesting that it did not inhibit elimination process of cimetidine, which is governed by OCT1, OCT2, and OAT3. Moreover, DA-9801 did not affect the pharmacokinetic characteristics of furosemide, as evidenced by its unchanged pharmacokinetic parameters. CONCLUSION: Inhibitory effects of DA-9801 on OCT1, OCT2, and OAT3 observed in vitro may not necessarily translate into in vivo herb-drug interactions in rats even at its maximum effective dose

    Development and evaluation of a plant-based air filter system for bacterial growth control

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    We investigated a novel plant-based air filter system for bacterial growth control. The volatile components released from the experimental plant (Cupressus macrocarpa) were used as the basis of the bacterial growth control and inhibition. We monitored the effect of light on the gas exhausted from the system, and we found that the presence of light induced an increase in the O2 concentration and a decrease in the CO2 concentration in the exhaust gas. A variety of Gram-positive and -negative bacteria was used to elucidate the effect of the exhaust gas on bacterial growth. In the Bacillus subtilis cultivation aerated with the exhaust gas (batch mode), we observed a decrease in the specific growth rate (μ = 0.227 h-1) compared with the control experiments (0.257 h-1). The same result was observed for the Staphylococcus aureus cultivation aerated with the exhaust gas. In the case of Gram-negative bacterial cultivation aerated with the gas, no significant inhibitory effect of the exhaust gas on the bacterial growth was observed. When the number of bacteria (B. subtilis) in a continuous culture was varied at different aeration rates (between 50 to 200 mL/min) using the exhaust gas, a prominent inhibitory effect was observed. Preliminary gas analysis showed that the major inhibitory factors in the exhaust gas are α- and β-pinene and linalool. The results show that the air filter system used in this study could be applied not only as a methodological aspect for estimating antibacterial activity but also for bacteria control in a given system.Keywords: Plant-based biofilter, Cupressus macrocarpa, Bacillus subtilis, Staphylococcus aureus, α-pinene, β-pineneAfrican Journal of Biotechnology Vol. 12(16), pp. 2027-203

    MRI traceability of superparamagnetic iron oxide nanoparticle-embedded chitosan microspheres as an embolic material in rabbit uterus

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    PURPOSEWe aimed to compare polyvinyl alcohol (PVA) particles with calibrated superparamagnetic iron oxide (SPIO) nanoparticle-loaded chitosan microspheres in a rabbit model, specifically regarding the relative distribution of embolic agents within the uterus based on magnetic resonance imaging (MRI) and pathological evaluation.METHODSTwelve New Zealand white rabbits underwent uterine artery embolization using either standard PVA particles (45–150 µm or 350–500 µm) or calibrated SPIO-embedded chitosan microspheres (45–150 µm or 300–500 µm). MRI and histopathological findings were compared one week after embolization.RESULTSCalibrated SPIO-loaded chitosan microspheres 45–150 µm in size were detected on T2-weighted images. On histological analysis, calibrated SPIO-embedded chitosan microspheres were found in both myometrium and endometrium, whereas PVA particles were found only in the perimyometrium or extrauterine fat pads. A proportional relationship was noted between the calibrated SPIO-embedded chitosan microsphere size and the size of the occluded artery.CONCLUSIONCalibrated SPIO-embedded chitosan microspheres induced greater segmental arterial occlusion than PVA particles and showed great potential as a new embolic material. SPIO-embedded chitosan microspheres can be used to follow distribution of embolic particles through MRI studies

    Cancer Morbidity of Foundry Workers in Korea

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    Foundry workers are potentially exposed to a number of carcinogens. This study was conducted to describe the cancer incidence associated with employment in small-sized Korean iron foundries and to compare those findings to the Korean population. Cancer morbidity in 208 Korean foundries was analyzed using the Standardized Incidence Ratio (SIR) and Standardized Rate Ratio (SRR). Overall cancer morbidity in foundry workers (SIR=1.11, 95% confidence interval [CI]=1.01-1.21) was significantly higher than that of Korean general population. Lung cancer (SIR=1.45, 95%CI=1.11-1.87) and lymphohematopoietcic cancer (SIR=1.58, 95%CI=1.00-2.37) in production workers were significantly high compared to Korean general population. Stomach cancer in fettling (SRR=2.10, 95%CI=1.10-4.01) and lung cancer in molding (SRR=3.06, 95%CI=1.22-7.64) and in fettling (SRR=2.63, 95%CI=1.01-6.84) were there significant elevations compared to office workers. In this study, statistically significant excess lung cancer was observed in production workers comparing to Korean general population and office workers. Also, cancer morbidity of overall cancer, lung cancer and stomach cancer was significantly increased with duration of employment at ten and more years comparing to Korean general population. These findings suggest in causal association between exposure to carcinogens during foundry work and cancer morbidity

    A Case of Non-Hodgkin's Lymphoma in Patient with Coombs' Negative Hemolytic Anemia and Idiopathic Thrombocytopenic Purpura

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    Coombs' negative autoimmune hemolytic anemia (AIHA) is a rare disease which shares similar clinical and hematological features with Coombs' positive AIHA, but its exact frequency remains unknown. There have been few reports of idiopathic thrombocytopenic purpura (ITP) and Coombs' negative AIHA associated with other lymphoproliferative disorders (LPDs). Since there is a well known association between LPDs and autoimmune phenomena, it is important to investigate the possibility of an underlying malignancy. We report a case of ITP and Coombs' negative AIHA associated with diffuse large B-cell lymphoma

    Electrically Robust Single-Crystalline WTe2 Nanobelts for Nanoscale Electrical Interconnects

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    As the elements of integrated circuits are downsized to the nanoscale, the current Cu-based interconnects are facing limitations due to increased resistivity and decreased current-carrying capacity because of scaling. Here, the bottom-up synthesis of single-crystalline WTe2 nanobelts and low- and high-field electrical characterization of nanoscale interconnect test structures in various ambient conditions are reported. Unlike exfoliated flakes obtained by the top-down approach, the bottom-up growth mode of WTe2 nanobelts allows systemic characterization of the electrical properties of WTe2 single crystals as a function of channel dimensions. Using a 1D heat transport model and a power law, it is determined that the breakdown of WTe2 devices under vacuum and with AlOx capping layer follows an ideal pattern for Joule heating, far from edge scattering. High-field electrical measurements and self-heating modeling demonstrate that the WTe2 nanobelts have a breakdown current density approaching approximate to 100 MA cm(-2), remarkably higher than those of conventional metals and other transition-metal chalcogenides, and sustain the highest electrical power per channel length (approximate to 16.4 W cm(-1)) among the interconnect candidates. The results suggest superior robustness of WTe2 against high-bias sweep and its possible applicability in future nanoelectronics
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