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A small physical change in the eye influences the entire neural information process along the visual pathway, causing perceptual errors and behavioral changes. Astigmatism, a refractive error in which visual images do not evenly focus on the retina, modulates visual perception, and the accompanying neural processes in the brain. However, studies on the neural representation of visual stimuli in astigmatism are scarce. We investigated the relationship between retinal input distortions and neural bias in astigmatism and how modulated neural information causes a perceptual error. We induced astigmatism by placing a cylindrical lens on the dominant eye of human participants, while they reported the orientations of the presented Gabor patches. The simultaneously recorded electroencephalogram activity revealed that stimulus orientation information estimated from the multivariate electroencephalogram activity was biased away from the neural representation of the astigmatic axis and predictive of behavioral bias. The representational neural dynamics underlying the perceptual error revealed the temporal state transition; it was transiently dynamic and unstable (approximately 350 ms from stimulus onset) that soon stabilized. The biased stimulus orientation information represented by the spatially distributed electroencephalogram activity mediated the distorted retinal images and biased orientation perception in induced astigmatism., In this study, we investigated the neural sources of perceptual error induced by the astigmatic distortion of the retinal image. We found a systematic distortion in the neural orientation representation estimated from the multivariate analysis of the electroencephalogram recordings, which supports the observed patterns of perceptual error.

목적: 소프트 콘택트렌즈 착용 및 관리 실태를 조사하여 렌즈 종류와 연령대별 착용자 간 차이가 있는지 알아보았다. 방법: 2018년 5월부터 7월까지 소프트 콘택트렌즈를 착용중인 중·고등학교 및 대학교 여학생 153명(중학생: 52명, 고등학생: 41명, 대학생: 60명)을 대상으로 착용 및 관리 실태에 관한 설문을 시행하였다. 결과: 미용 콘택트렌즈를 착용하는 경우(62.09%)가 투명 콘택트렌즈(37.91%) 보다 2배가량 높았으며, 착용 목적으로는 미용상 착용하는 비율(51.63%)이 가장 높았다. 콘택트렌즈의 유효 착용 기간보다 오래 착용하는 경우(45.75%)와 콘택트렌즈를 착용하고 화장을 하는 경우(84.97%)가 많았으며, 보관 용기(73.72%)와 보관 용액(49.02%)의 교체주기를 잘 모르는 경우가 많았다. 보관용액의 유통기한을 정확하게 인지하지 못하고 사용하는 사람이 75.82%로 높은 수치를 보였다. 보관 용기를 올바르게 세척하지 않는 인원은 65.23%로 과반수가 적절하게 관리하지 못하고 있었다. 콘택트렌즈 구매시 교육받은 비율은 투명 렌즈와 미용 렌즈 착용자를 서로 비교했을 때 차이가 없었지만, 연령대별로 비교했을 때 중학생이 고등학생과 대학생보다 관리 방법을 안내받은 비율이 더 높았다(p＜0.05). 결론: 소프트 콘택트렌즈 착용 여학생들은 유효 착용 기간, 착용 시 화장법, 보관 용기와 용액의 관리 방법 등에 대해 정확히 숙지하지 못하고 있었다. 따라서 처음 착용하는 시기인 10대 초반뿐 만 아니라 고등학생 및 20대에서도 지속적인 교육 및 안내가 필요할 것이다.

The seeds of Cassia tora (C. tora) species mainly contain anthraquinone, anthraquinone glycoside, and naphthalene derivatives. We investigated the anti-apoptotic effects of C.tora seed extract and its isolated compounds on blue-light-induced lipofuscin (A2E)-loaded human retinal pigment epithelial (RPE) cells. For analysis of the C. tora extract, high-performance liquid chromatography method was used. A2E-loaded human retinal pigment epithelial cells and blue light were used to create excessive photo-oxidation to induce cell death. Lactate dehydrogenase (LDH) assay was used to measure cell cytotoxicity, and the mRNA expression of genes involved in apoptosis was examined to evaluate the mechanism of cell death. C.tora extract, n-hexane fraction, and chrysophanol were found to inhibit apoptotic cell death. Additionally, C.tora extract, n-hexane fraction, and chrysophanol reduced the mRNA expression of genes involved in the apoptosis pathway. C.tora and chrysophanol were considered to inhibit apoptosis and oxidative stress response. The major component of C. tora has a protective effect against apoptosis. The ingredients of C. tora can be used as therapeutic substances or to prevent diseases caused by the excessive oxidation of A2E substances in the retina, such as in age-related macular degeneration.

Background and Objectives: acute kidney injury (AKI), formerly called acute renal failure (ARF), is commonly defined as an abrupt decline in renal function, clinically manifesting as a reversible acute increase in nitrogen waste products—measured by blood urea nitrogen (BUN) and serum creatinine levels—over the course of hours to weeks. AKI occurs in about 20% of all hospitalized patients and is more common in the elderly. Therefore, it is necessary to prevent the occurrence of AKI, and to detect and treat early, since it is known that a prolonged period of kidney injury increases cardiovascular complications and the risk of death. Despite advances in modern medicine, there are no consistent treatment strategies for preventing the progression to chronic kidney disease. Through many studies, the safety and efficacy of natural products have been proven, and based on this, the time and cost required for new drug development can be reduced. In addition, research results on natural products are highly anticipated in the prevention and treatment of various diseases. In relation to AKI, many papers have reported that many natural products can prevent and treat AKI. Conclusions: in this paper, the results of studies on natural products related to AKI were found and summarized, and the mechanism by which the efficacy of AKI was demonstrated was reviewed. Many natural products show that AKI can be prevented and treated, suggesting that these natural products can help to develop new drugs. In addition, we may be helpful to elucidate additional mechanisms and meta-analysis in future natural product studies.

Astigmatism is a prevalent optical problem in which two or more focal points blur the retinal image at a particular meridian. Although many features of astigmatic vision, including orientation perception, are impaired at the retinal image level, the visual system appears to partly restore perceptual impairment after an extended period of astigmatism. However, the mechanism of orientation perception restoration in chronic astigmatism has not yet been clarified. We investigated the notable reduction of perceptual error in chronic astigmatism by comparing the orientation perception of a chronic astigmatism group with the perception of a normal-vision group, in which astigmatism was transiently induced. We found that orientation perception in the chronic group was more accurate than in the normal vision group. Interestingly, the reduction of perceptual errors was automatic; it remained even after the optical refractive errors were fully corrected, and the orientation perception was much more stable across different orientations, despite the uneven noise levels of the retinal images across meridians. We provide here a mechanistic explanation for how the compensation of astigmatic orientation perception occurred, using neural adaptation to the biased distribution of orientations.

Achillea millefolium L. (AM) is an aromatic herb with a variety of pharmacological properties, such as anti-inflammatory and anti-allergic activities. However, AM’s effects on atopic dermatitis (AD) have not been investigated. This study evaluates the anti-AD activity of 50% ethanol-extracted AM in murine macrophage Raw 264.7 cells, in tumor necrosis factor-alpha/interferon-gamma (TNF-[Formula: see text]/IFN-[Formula: see text])-stimulated human immortal keratinocyte HaCaT cells in vitro, and in Biostir-AD-treated NC/Nga mice in vivo. The results showed that AM significantly downregulated expression of pro-inflammatory cytokines, such as INOS, COX-2, and interleukin (IL)-6 in lipopolysaccharide (LPS)-treated Raw 264.7 cells. The mRNA expressions of INOS, COX-2, and IL-6 decreased by 76.1%, 69.3%, and 31.8%, respectively. Overexpression of chemokines, such as activation-regulated chemokine and macrophage-derived chemokine, regulated on activation of normal T-cell expressed and secreted, and IL-8 was inhibited by 70.01%, 52.91%, 73.53%, and 18.93%, respectively, in TNF-[Formula: see text]/IFN-[Formula: see text]-stimulated HaCaT cells by downregulating the mitogen-activated protein kinase, I[Formula: see text]B[Formula: see text], and the signal transducer and activator of transcription 1 signaling pathways. AD-like symptoms, such as elevated serum immunoglobin E levels, epidermal thickening, high dermatitis severity score, transepidermal water loss, and reduced skin hydration, were relieved by the dietary administration of AM in Biostir-AD-treated NC/Nga mice. In addition, filaggrin expression increased significantly in AM-treated groups. These results suggest that AM could be a useful candidate for AD treatment.

Along with the remarkable growth in the complexity of semiconductor fabrication technology, chemical mechanical planarization (CMP) has evolved and become progressively more sophisticated over the years, enabling the implementation of novel integration schemes. This paper discusses current research and development trends in one specific aspect of the CMP technology, namely, ceria particle usage for advanced technology nodes and provides some perspectives on how to improve CMP performance metrics of the current ceria abrasives and ceria-based CMP slurries and move forward to the next phase.

We demonstrate the synthesis of poly(methyl methacrylate) (PMMA) and poly(styrene-b-methyl methacrylate) (P(S-b-MMA)) brushes on crosslinked random copolymer thin films, compositionally varied poly(styrene-r-glycidyl methacrylate) (P(S-r-GMA)), which can be further functionalized with a molecule featuring an initiator group upon crosslinking to form highly stable thin films. With careful optimizations, PMMA brushes were successfully grown from the surfaces of initiator functionalized P(S-r-GMA) via surface-initiated atom transfer radical polymerization. The grafting densities of the PMMA and P(S-b-MMA) brushes were effectively controlled to be in different density regimes by controlling the composition of P(S-r-GMA) and post-crosslinking functionalization methods. Synthesized BCP brushes were stable upon repetitive washing and thermal annealing processes even at high grafting density, highlighting that the outstanding stability of crosslinked P(S-r-GMA) thin films enables close examination of the morphology of thermally annealed P(S-b-MMA) brushes in different grafting density regimes.

In this study a new hybrid energy dissipation device is developed by combining a steel slit damper and rotational friction dampers in parallel to be used for seismic retrofit of structures. Compared with the conventional slit dampers with the same yield strength, the hybrid damper has an advantage in that only friction dampers are activated for small earthquakes or strong wind, and both friction and slit damper work simultaneously for strong earthquakes. Cyclic loading tests of the friction, slit, and the combined hybrid dampers are carried out to evaluate their seismic energy dissipation capability. Finite element analyses of the test specimens are also carried out for comparison, which correspond well with the test results. The hybrid dampers are applied to seismic retrofit of an reinforced concrete analysis model structure, where it is observed that the dampers are effective in restraining the building performance within a given target performance level. The fragility analysis of the structure shows that the probabilities of reaching four limit states decrease significantly after the seismic retrofit. The effect is most significant in the reduction of the probability of reaching the complete damage state.

This study investigates the performance and design of an aluminum honeycomb panel attached to the face of a steel column for reducing local damage caused by vehicle collision. The dynamic p...

The special truss moment frame (STMF) is known to provide higher lateral stiffness with relatively less weight as compared to conventional moment resisting frames. In this study the seismic performance of STMF was investigated by fragility analyses and the results were compared with the performance of special moment resisting frames. Then seismic retrofit scheme was proposed by installing a viscous damper in the special segment to meet enhanced seismic performance objective. The required amount of additional viscous damping was determined based on the nonlinear static procedure provided in the ASCE/SEI 41-10. The analysis results showed that the STMF showed larger stiffness and strength but smaller ductility compared with the moment frames, which resulted in similar seismic fragility in both structures. The seismic performance of STMF with viscous dampers in the special segments turned out to meet the desired target performance, and the effect of adding viscous dampers in the seismic fragility was most significant in the complete damage state.

Purpose: This study investigated differences in stereoscopic fusional area between those with good and poor stereoacuity in viewing stereoscopic displays. Methods: Stereo acuity of 39 participants (18 males and 21 females, 23.6±3.15years) was measured with the random dot stereo butterfly method. Participants with stereo-blindness were not included.Stereoscopic fusional area was measured using stereoscopic stimulus by varying the amount of horizontal disparity in astereoscopic 3D TV. Participants were divided into two groups of good and poor stereo acuity. Criterion for good stereoacuity was determined as less than 60 arc seconds. Measurements arising from the participants were statisticallyanalyzed. Results: 26 participants were measured to have good stereo acuity and 13 participants poor stereo acuity. Incase of the stereoscopic stimulus farther than the fixation point, threshold of horizontal disparity for those with poorstereo acuity were measured to be smaller than the threshold for those with good stereo acuity, with a statisticallysignificant difference. On the other hand, there was no statistically significant difference between the two groups, in caseof the stereoscopic stimulus nearer to the fixation point. Conclusions: In viewing stereoscopic displays, the boundary ofstereoscopic fusional area for the poor stereo acuity group was smaller than the boundary of good stereo acuity grouponly for the range behind the display. Hence, in viewing stereoscopic displays, participants with poor stereo acuity wouldhave more difficulty perceiving the fused image at farther distances compared to participants with good stereo acuity.Key words: Stereo acuity, Stereoscopic fusional area, Stereoscopic display

Dept of Civil and Architectural Engineering, Sungkyunkwan University, Suwon 440-746, KoreaABSTRACT Structures are often subject to vehicle collision which can be accidental or terrorist attack. Previous research shows that the damage in major columns may result in progressive collapse of a whole building. This study investigates the performanc e of a steel column standing on a reinforced concrete footing subjected to a vehicle collision. The size and the axial load of the steel column are determined based on the assumption that it is the first story corner column in a typical three-story building with s ix meter span length. The finite element model of a eight-ton single unit truck provided by the NCAC (National Crash Analysis Center) is used in the numerical analysis. The finite el ement analysis is performed using the LS - DYNA, and the results show that the beha vior of the column subjected to car impact depends largely on the column-foundation connection detail.Keywords : vehicle collision, progressive collapse, FEM explicit analysis

The threshold for binocular disparity for which a participant can observe a clear stereoscopic image on a 3D TV using Patterned Retarder technology and polarizing eyeglasses is determined for a viewing distance of 2.5 m. An optotype, the letter “m” with a line thickness of 1.08 mm in the upward or downward direction, was used as the stereoscopic stimulus. Under the measurement conditions of the increase and decrease of binocular disparity of the stereoscopic stimulus, the binocular disparity thresholds for 40 participants were measured for the horizontal direction. Most of the participants were in their twenties. The thresholds were measured to be slightly larger for the condition of increasing binocular disparity compared with the condition of decreasing binocular disparity. Personal differences were measured to be noticeable.

Titanium and its alloys have been widely used for medical and aerospace applications because of their excellent attributes of high specific strength, corrosion resistance, and biocompatibility. However, it is not easy to produce the complex shaped parts due to their poor castability and machinability. Metal injection molding (MIM) is one of suitable processing technique to produce the complex shaped parts in order to reduce the manufacturing cost. In this study, complex shaped Ti-6Al-4V compacts was prepared by MIM process for airplane application. The effects of high molecular binder content and different compact’s set-up during thermal debinding on the distortion of complex shaped compacts were measured and evaluated. The binder with 10 % APP (Atactic polypropylene) was found to have better shape retention for the parts. Furthermore the results indicate that high distortion occurs at early stage of thermal debinding process. The use of supports during thermal debinding can significantly reduce the distortion of the final parts.

In this paper, two kinds of advanced powder processing techniques such as Metal Injection Molding (MIM) and Direct Laser Forming (DLF) were introduced to fabricate complex shaped Ti alloy parts which have been widely used for various industrial and medical applications because of their excellent characteristics of low density, high corrosion resistance and high biocompatibility but need high processing cost because of poor workability. The MIM process has been tried to strengthen Ti-6Al-4V alloy compacts by addition of fine Mo, Fe and Cr powders, and enhanced tensile strength of 1030 MPa with 15.1 % elongation was obtained by an addition of 4 mass%Cr because of the microstructural modification but also the solution strengthening in beta phase. DLF process has been tried to improve the honeycomb porous structure from Ti-6Al-7Nb powder material, and the honeycomb structure with 300 m holes showed good mechanical compatibility and superb biocompatibility in osteoblasts culturing.

In this paper the seismic performance of a flat plate wall system structure was evaluated based on the ATC-63 approach, and the results were compared with those of a wall slab structure having the same size. As analysis model structures, a twelve story flat plate wall structure and a wall slab structure were designed based on the KBC-2009, and their seismic performances and collapse behaviors were evaluated by nonlinear static and incremental dynamic analyses(IDA). It was observed that the flat plate wall structure was designed with smaller amount of reinforced concrete, and showed slightly larger displacement response compared with those of the wall slab structure. The collapse margin ratios of the two structures obtained from the incremental dynamic analyses satisfied the limit states specified in the ATC-63, and the structures turned out to have enough capacity to resist the design level seismic load.

Ti-10V-2Fe-3Al is one of super elastic Ti alloys, which is the b type Ti alloy and shows the excellent properties such as high specific strength and corrosion resistance. By the combination of Cold working and heat treatment, high strength as same as the steels are obtained. Therefore, Ti-10V-2Fe-3Al is hoped to be a next generation’s spring material. In this study, Metal Injection Molding of super elastic Ti alloy materials are investigated by changing the process parameters such as powder type (mixed elemental or alloy), debinding and sintering conditions, and heat treatment conditions to obtain the excellent super elastic properties. Tensile strength of injection molded Ti-10V-2Fe-3Al compacts sintered at 1250 with mixed elemental powders showed approximately 85% of wrought materials. On the other hand, alloy powder compacts showed about 80% strength of wrought materials. Their super elastic behavior depended strongly on the heat treatment conditions.

Bowel ischemia is a life-threatening surgical emergency. We report a case of rapidly progressive bowel necrosis in a previously healthy child without proven mechanical small bowel obstruction. The definite diagnosis was established at the time of an exploratory operation. Of note, imaging studies and even a laparotomy did not reveal any evidence of acute appendicitis or mechanical obstruction such as intussusception or Meckel's diverticulum. During hospitalization, since we could not rule out surgical abdomen after inconclusive image findings, we closely followed the patient and repeated physical examinations carefully. Eventually surgical exploration was performed based on changes in clinical condition, which proved to be the right decision for the patient. We propose that in children with suspected strangulation of small bowel obstruction, especially when imaging findings do not provide a conclusive diagnosis, the timely exploratory surgical approach ought to be chosen based on carefully observed clinical findings and other evaluations.

Titanium and its alloys have been widely used for medical and aerospace applications because of their excellent attributes of light metal, high strength, high corrosion resistance and high biocompatibility. Especially, Ti-6Al-7Nb alloy has been developed as a more suitable biomaterial to replace Ti-6Al-4V alloy, because vanadium is toxic element to the biological body. However, it is not easy to fabricate the complex shaped and precise parts by the conventional methods due to their poor castability and machinability. In this study, laser forming technique has been applied to solve the above problems. The precise structure was obtained by optimizing the laser forming parameters. Using this technique, a honeycomb structure was fabricated effective to grow the neighboring tissue and also encourage osseointegration. Finally, mouse osteoblasts were cultured on the formed structures, resulted in the effectiveness of the honeycomb structure for biocompatibility.

The direct metal laser sintering process was applied to produce density gradient materials of stainless steel 316L. In order to understand the mechanism of forming porous structure, the influence of laser power, scan rate and scan pitch on the porosity were investigated by measuring density of produced samples and observing cross-sectional microstructures. Laser power greatly affected to the porosity by forming clusters of melted metal powders. It was found that the size change of clusters plays a role in forming porous structure. Eventually, three dimensional sample owing density gradient structures was manufactured.

This paper reports an improved interfacial structure between electrode and electrolyte of Solid Oxide Fuel Cell (SOFC). We employed an imprint process to give fine patterns onto a ceramic electrolyte sheet. The imprint process is a powerful tool to transcribe nano- to micro-patterns on materials. In the present work, a sheet of ceramic compound material was prepared, and micro patterns were given on the sheet. After debinding and sintering, dense ceramic sheet with fine patterns were obtained. We prepared three kinds of electrolyte sheets with different surface patterns using this technique. After applying anode and cathode layers, the three fuel cell samples were assembled to test the cell performance. It was resulted that the finer pattern caused the best performance in the three samples.

This paper reports a magnetic actuator using interaction between micro magnetic elements. It was already reported that the present actuator can work even if the structure was miniaturized to nano-scale. In the present work, simple fabrication process with photolithography and PDMS casting was employed to obtain beam type structures with micro array of magnetic elements on their surface. Two samples with simple grid patterns were prepared for testing. These samples had the same grid pattern but different orientation, which caused directly opposite bending deformation under the same applied magnetic field. We used magneto finite element method (FEM) to explain the behavior of the present actuators.