234 research outputs found

    Pointing-and-Acquisition for Optical Wireless in 6G: From Algorithms to Performance Evaluation

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    The increasing demand for wireless communication services has led to the development of non-terrestrial networks, which enables various air and space applications. Free-space optical (FSO) communication is considered one of the essential technologies capable of connecting terrestrial and non-terrestrial layers. In this article, we analyze considerations and challenges for FSO communications between gateways and aircraft from a pointing-and-acquisition perspective. Based on the analysis, we first develop a baseline method that utilizes conventional devices and mechanisms. Furthermore, we propose an algorithm that combines angle of arrival (AoA) estimation through supplementary radio frequency (RF) links and beam tracking using retroreflectors. Through extensive simulations, we demonstrate that the proposed method offers superior performance in terms of link acquisition and maintenance.Comment: 8 pages, 6 figures, magazine pape

    Elevation of serum lactate dehydrogenase in patients with pectus excavatum

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    INTRODUCTION: Pectus excavatum is the most common congenital chest wall deformity and the depression of the anterior chest wall, which compresses the internal organs. The aim of the present study is to investigate the effects of pectus excavatum on blood laboratory findings. MATERIAL AND METHODS: From March 2011 to December 2011, 71 patients with pectus excavatum who visited Seoul Saint Mary Hospital for Nuss procedure were reviewed and analyzed. The blood samples were routinely taken at the day before surgery and pectus bar removal was usually performed in 2 to 3 years after Nuss procedure. To investigate the effects on blood laboratory findings, preoperative routine blood laboratory data and postoperative changes of abnormal laboratory data were analyzed. RESULTS: Only lactate dehydrogenase (LDH), one of 26 separate routine laboratory tests, was abnormal and significantly elevated than normal value (age <10, p = 0.008; age ≥10, p < 0.001). However, there was no significant correlation between LDH levels and severities of pectus excavatum. The symmetric subgroup had significantly higher LDH level than the asymmetric subgroup (p <0.001) and there was a significant decrease of LDH level after correction of deformity (p = 0.017). CONCLUSION: In conclusion, only LDH, one of the routine laboratory tests, was significantly elevated than normal value, which was thought to be caused by etiologies of pectus excavatum and the compression of the internal organs. Further studies on LDH including isoenzyme studies in patients with pectus excavatum will be needed, and these studies will provide a deeper and wider comprehension of pectus excavatum

    Effects of Hyul-Bu-Chuke-Tang on Erythrocyte Deformability and Cerebrovascular CO2 Reactivity in Normal Subjects

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    Aim. Hyul-bu-chuke-tang (HCEt) is a well-known traditional herbal medicine that is used for the treatment of ischemic cerebrovascular disorders. We investigated the acute effects of HCEt on erythrocyte deformability and cerebrovascular CO2 reactivity (CVR) in healthy male subjects. Materials and Methods. We examined erythrocyte deformability in an HCEt group (n = 14) and a control group (n = 10). CVR was measured using hyperventilation-induced CO2 reactivity of the middle cerebral artery and transcranial Doppler (TCD) in the HCEt group (n = 11). A historical control group (n = 10) of CVR measurements was also created from our previous study. All measurements were performed prior to and 1, 2, and 3 hours after HCEt administration. Results. HCEt significantly improved erythrocyte deformability 1 hour after administration compared to the control group (2.9 ± 1.1% versus −0.6 ± 1.0%, P = 0.034). HCEt significantly improved the CVR 2 hours after administration compared to the historical control group (9.1 ± 4.0% versus −8.1 ± 4.1%, P = 0.007). The mean blood pressure and pulse rate did not vary from baseline values in either group. Conclusions. We demonstrated that HCEt improved erythrocyte deformability and CVR. Our findings suggest that an improvement in erythrocyte deformability contributes to HCEt's effect on cerebral microcirculation

    Post-transplant lymphoproliferative disorder presented as small bowel intussusception in adult liver transplant patient

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    Intestinal obstruction after liver transplant is a rare complication, with diverse clinical manifestations. Intestinal adhesion is the most common cause. However, internal hernia, abdominal wall hernia, and neoplasm are also reported. Intussusception is another rare cause of intestinal obstruction, which has been reported primarily in pediatric patients. Herein, we report a case of intestinal obstruction from intussusception in an adult liver transplant patient associated with post-transplant lymphoproliferative disorder

    Microvasculature remodeling in the mouse lower gut during inflammaging

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    Inflammaging is defined as low-grade, chronic, systemic inflammation in aging, in the absence of overt infection. Age-associated deterioration of gastrointestinal function could be ascribed to the inflammaging, although evidence is yet to emerge. Here we show that microvessels in aging mouse intestine were progressively deprived of supportive structures, microvessel-associated pericytes and adherens junction protein vascular endothelial (VE)-cadherin, and became leaky. This alteration was ascribed to up-regulation of angiopoetin-2 in microvascular endothelial cells. Up-regulation of the angiopoietin-2 was by TNF-α, originated from M2-like residential CD206 + macrophages, proportion of which increases as animal ages. It was concluded that antigenic burdens encountered in intestine throughout life create the condition of chronic stage of inflammation, which accumulates M2-like macrophages expressing TNF-α. The TNF-α induces vascular leakage to facilitate recruitment of immune cells into intestine under the chronic inflammatory setting. © Author(s) 2017.1

    Histologic discrepancy between endoscopic forceps biopsy and endoscopic mucosal resection specimens of colorectal polyp in actual clinical practice

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    Background/AimsWe aimed to assess the rate of histologic discrepancy (HD) between endoscopic forceps biopsy (EFB) and totally resected specimens in colorectal polyp and analyze the risk factors of discordant group, especially under-diagnosis (UD) cases before complete removal of colorectal polyp.MethodsFrom 2010 to 2015, a total of 290 polyps in 210 patients which had baseline pathology report before endoscopic resection (ER) were analyzed. UD cases were defined as those in which the diagnosis changed to a more advanced histologic feature after ER.ResultsA change in the final histology after ER was noted in 137 cases (47.2%), and after excluding 9 insignificant cases, 128 cases were further categorized into over-diagnosed and under-diagnosed group. UD occurred in 86 cases (29.7%) and change from benign to malignancy was noted in 26 cases (8.9%). On univariate analysis, a larger polyp size (>10 mm) was significantly associated with both HD (P10 mm was the single most significant predictor of both HD (P10 mm was the most important predictor of both HD and UD. We should be careful in making treatment strategy of colorectal polyp based on histologic report of EFB especially when the size of polyp is >10 mm

    Zanthoxylum ailanthoides

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    Zanthoxylum ailanthoides (ZA) has been used as folk medicines in East Asian and recently reported to have several bioactivity; however, the studies of ZA on the regulation of triacylglycerol (TG) biosynthesis have not been elucidated yet. In this study, we examined whether the methanol extract of ZA (ZA-M) could reduce oleic acid- (OA-) induced intracellular lipid accumulation and confirmed its mode of action in HepG2 cells. ZA-M was shown to promote the phosphorylation of AMPK and its upstream LKB1, followed by reduction of lipogenic gene expressions. As a result, treatment of ZA-M blocked de novo TG biosynthesis and subsequently mitigated intracellular neutral lipid accumulation in HepG2 cells. ZA-M also inhibited OA-induced production of reactive oxygen species (ROS) and TNF-α, suggesting that ZA-M possess the anti-inflammatory feature in fatty acid over accumulated condition. Taken together, these results suggest that ZA-M attenuates OA-induced lipid accumulation and inflammation through the activation of LKB1/AMPK signaling pathway in HepG2 cells

    Secondary Amyloidosis Associated with Multiple Sclerosis

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    Background Multiple sclerosis (MS) is a demyelinating disease of the central nervous system. Secondary amyloidosis can occur as a complication of chronic systemic inflammatory and infectious diseases. Until now there has been no report of secondary amyloidosis associated with MS. We report herein a case of renal biopsy-proven secondary amyloidosis in a patient with MS. Case Report A 41-year-old woman with MS was hospitalized due to aggravated quadriparesis and edema in both lower extremities. Laboratory findings showed nephrotic-range proteinuria and hypoalbuminemia. A percutaneous renal biopsy procedure was performed, the results of which revealed secondary amyloid-A-type amyloidosis associated with MS. Conclusions This is the first report of secondary amyloidosis associated with MS. J Clin Neurol 2009;5:146-14
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