Photosensor-Based Latency Measurement System for Head-Mounted Displays.

In this paper, a photosensor-based latency measurement system for head-mounted displays (HMDs) is proposed. The motion-to-photon latency is the greatest reason for motion sickness and dizziness felt by users when wearing an HMD system. Therefore, a measurement system is required to accurately measure and analyze the latency to reduce these problems. The existing measurement system does not consider the actual physical movement in humans, and its accuracy is also very low. However, the proposed system considers the physical head movement and is highly accurate. Specifically, it consists of a head position model-based rotary platform, pixel luminance change detector, and signal analysis and calculation modules. Using these modules, the proposed system can exactly measure the latency, which is the time difference between the physical movement for a user and the luminance change of an output image. In the experiment using a commercial HMD, the latency was measured to be up to 47.05 ms. In addition, the measured latency increased up to 381.17 ms when increasing the rendering workload in the HMD.

The Risk of Abdominal Obesity according to the Degree of Non-Alcoholic Fatty Liver Disease in Korean Men.

Although non-alcoholic fatty liver disease has been reported as a cardiometabolic risk factor, the effect of non-alcoholic fatty liver is yet to be clarified on abdominal obesity. Therefore, this study was conducted to investigate the longitudinal relationship of non-alcoholic fatty liver on the development of abdominal obesity. The study participants were composed of 11,212 Korean men without abdominal obesity. They were followed up from 2005 to 2010 to be monitored for the development of abdominal obesity according to their degree of non-alcoholic fatty liver disease (normal, mild, and moderate to severe). Cox-proportional hazard model was used to calculate the hazard ratios for abdominal obesity according to the degree of non-alcoholic fatty liver disease. While the average incidence was 15.5%, the incidence of abdominal obesity increased according to the degree of non-alcoholic fatty liver (normal: 11.6%, mild: 25.2%, moderate to severe: 41.0%, P < 0.001). Multivariable-adjusted hazard ratios for abdominal obesity independently increased proportionally to the degree of NAFLD (mild [1.07; 0.94-1.23], moderate to severe [1.58; 1.11-2.26], P for trend < 0.001). The risk of abdominal obesity increased proportionally to the degree of non-alcoholic fatty liver disease. This finding guarantees further studies to reveal the incidental relationship of abdominal obesity with non-alcoholic fatty liver disease.

Recto-Bartholin's duct fistula: a case report.

Bartholin's duct cysts, the most common growths in the vulva, occur in the labia majora. The cyst may become infected, and an abscess may develop in the gland. Rectovaginal fistula is a rare complication and its formation is secondary to Bartholin's cyst; only 4 cases have been reported in the literature so far. In this case, the fistula was located between the rectum and a Bartholin's duct, rather than the vagina and the rectum. We present the first case of a recto-Bartholin's duct fistula, performed surgical excision and fistulectomy. Postoperative treatment with antibiotics resulted in the complete resolution of all lesions at the 3-month follow-up.

[A case of spindle cell carcinoma of the stomach presenting with hematochezia and weight loss due to fistulous tract formation with colon].

Spindle cell carcinoma (SpCC) is a rare tumor consisting of spindle cells which express cytokeratin. Despite recent advances in immunohistochemical and genetic studies, precise histogenesis of SpCC is still controversial and this tumor had been referred to with a wide range of names (in the past): carcinosarcoma, pseudosarcoma, sarcomatoid carcinoma, pseudosarcomatous carcinoma, and collision tumor. Recently, the authors experienced an extremely rare case of SpCC arising from the stomach. A 64-year-old male presented with unintended weight loss and hematochezia. Endoscopic examination revealed a fistulous tract between the stomach and the transverse colon which was made by direct invasion of SpCC of the stomach to the colon. Histologically, the tumor was positive for both vimentin and cytokeratin but negative for CD117, CD34, actin, and desmin. Herein, we report a case of SpCC arising from the stomach that formed a fistulous tract with the colon which was diagnosed during evaluation of hematochezia and weight loss.

Recurrent Insulin Autoimmune Syndrome Caused by α-Lipoic Acid in Type 2 Diabetes.

Insulin autoimmune syndrome (IAS) is characterized by spontaneous hypoglycemia caused by insulin autoantibodies in the absence of exogenous insulin administration. Some drugs containing sulfhydryl compounds are known to initiate the onset of IAS. A 67-year-old female who had diabetes for 5 years visited the outpatient clinic at our institution due to diabetic peripheral polyneuropathy. She was prescribed α-lipoic acid (ALA), which contains two sulfur atoms. Two weeks later, she complained of recurrent hypoglycemic symptoms. We detected a high level of insulin and high titers of insulin autoantibodies. Her human leukocyte antigen (HLA) genotype included the DRB1*0406 allele, which indicates a high level of susceptibility to IAS. She was treated with prednisolone. After this episode, she experienced two more hypoglycemic events after taking ALA for diabetic neuropathy in other hospitals. As ALA can be used to treat diabetic peripheral polyneuropathy, physician discretion is advised based on the possibility of IAS due to ALA in diabetic patients.

Reflow of phosphorous silicate glass layer formed on textured Si surface in crystalline Si solar cells.

We have investigated the reflow behavior of phosphorus silicate glass (PSG) layer formed on textured Si surface using transmission electron microscopy and simulation. For conventional wet oxidation process, stress-dependent surface reaction and stress-dependent oxidant diffusion led to the oxidation retardation in both convex and concave regions of the textured Si surface, respectively. However, PSG film formed by POCl3-diffusion underwent reflow, resulting in the formations of thinner and thicker PSG films in convex and concave regions, respectively. Simulation results showed that the reflow of PSG films causes lateral thermal mismatch stresses to increase and decrease in convex and concave regions, respectively.

Applicability of grid-net detection system for landfill leachate and diesel fuel release in the subsurface.

The grid-net system estimating the electrical conductivity changes was evaluated as a potential detection system for the leakage of diesel fuel and landfill leachate. Aspects of electrical conductivity changes were varied upon the type of contaminant. The electrical conductivity in the homogeneous mixtures of soil and landfill leachate linearly increased with the ionic concentration of pore fluid, which became more significant at higher volumetric water contents. However, the electrical conductivity in soil/diesel fuel mixture decreased with diesel fuel content and it was more significant at lower water contents. The electrode spacing should be determined by considering the type of contaminant to enhance the electrode sensitivity especially when two-electrode sensors are to be used. The electrode sensitivity for landfill leachate was constantly maintained regardless of the electrode spacings while that for the diesel fuel significantly increased at smaller electrode spacings. This is possibly due to the fact that the insulating barrier effect of the diesel fuel in non-aqueous phase was less predominant at large electrode spacing because electrical current can form the round-about paths over the volume with relatively small diesel fuel content. The model test results showed that the grid-net detection system can be used to monitor the leakage from waste landfill and underground storage tank sites. However, for a successful application of the detection system in the field, data under various field conditions should be accumulated.

Protective effect of overlying geosynthetic on geomembrane liner observed from landfill field tests and inclined board laboratory experiments.

Geosynthetic liner systems are generally installed in landfill sites to prevent toxic leachate from escaping into the adjoining environment by utilizing their impervious characteristics. Therefore, it is important to protect the geomembrane from being damaged or destroyed during all phases of landfilling, namely landfill construction, waste tipping and landfill closure. This paper presents firstly the observed performance of a geomembrane liner from a landfill site where the geomembrane liner was installed on the slopes of a Korean landfill; and secondly the results of an inclined board laboratory test. Two types of experiments were conducted to identify the protecting effect of the overlaying geosynthetic on the geomembrane liners. At a testing landfill site, the slope consisted of three different sub-inclines and two 2-m-wide intermediate levels. The sub-inclines were each 8 m in vertical height and their angle of inclination was 1: 1.5 (vertical: horizontal). The reported observations were made for a time period of approximately 1 year, until the landfill was filled with wastes to the top of the uppermost slope. In addition, inclined board laboratory tests were carried out. During the inclined board test, a base table is inclined slowly and steadily until the block located on the base table starts to slide, when the tension and displacements of two geosynthetics, namely the geomembrane liner and protecting geotextile, are measured. In conclusion, test results showed that the down-drag force generated by waste accumulation and sliding of upper material was to a large extent dissipated through the elongation of the protecting geosynthetic overlying the geomembrane and thus was not transferred to the geomembrane. Unless the protecting geosynthetic undergoes structural failure, this stress relaxation phenomenon continues to occur so that the magnitude of tensile force to be applied on the geomembrane remains marginal.