Joint Carrier Fequency Synchronization and Channel Estimation for OFDM Systems Via the EM Algorithm

A joint carrier frequency synchronization and channel estimation scheme is proposed for orthogonal frequencydivision multiplexing (OFDM) system. In the proposed scheme, carrier frequency synchronization and channel estimation are performed iteratively via the expectation–maximization (EM) algorithm using an OFDM preamble symbol. Moreover, we analytically investigate the effect of frequency offset error on the mean square error (MSE) performance of channel estimator. Simulation results present that the proposed scheme achieves almost ideal performance for both channel and frequency offset estimation.This work was supported by the University IT Research Center Project and the Brain Korea 21 Project

Abalone visceral extract inhibit tumor growth and metastasis by modulating Cox-2 levels and CD8+ T cell activity

<p>Abstract</p> <p>Background</p> <p>Abalone has long been used as a valuable food source in East Asian countries. Although the nutritional importance of abalone has been reported through <it>in vitro </it>and <it>in vivo </it>studies, there is little evidence about the potential anti-tumor effects of abalone visceral extract. The aim of the present study is to examine anti-tumor efficacy of abalone visceral extract and to elucidate its working mechanism.</p> <p>Methods</p> <p>In the present study, we used breast cancer model using BALB/c mouse-derived 4T1 mammary carcinoma and investigated the effect of abalone visceral extract on tumor development. Inhibitory effect against tumor metastasis was assessed by histopathology of lungs. Cox-2 productions by primary and secondary tumor were measured by real-time RT-PCR and immunoblotting (IB). Proliferation assay based on [³H]-thymidine incorporation and measurement of cytokines and effector molecules by RT-PCR were used to confirm tumor suppression efficacy of abalone visceral extract by modulating cytolytic CD8+ T cells. The cytotoxicity of CD8⁺T cell was compared by JAM test.</p> <p>Results</p> <p>Oral administration of abalone visceral extract reduced tumor growth (tumor volume and weight) and showed reduced metastasis as confirmed by decreased level of splenomegaly (spleen size and weight) and histological analysis of the lung metastasis (gross analysis and histological staining). Reduced expression of Cox-2 (mRNA and protein) from primary tumor and metastasized lung was also detected. In addition, treatment of abalone visceral extract increased anti-tumor activities of CD8⁺T cells by increasing the proliferation capacity and their cytolytic activity.</p> <p>Conclusions</p> <p>Our results suggest that abalone visceral extract has anti-tumor effects by suppressing tumor growth and lung metastasis through decreasing Cox-2 expression level as well as promoting proliferation and cytolytic function of CD8⁺T cells.</p

Association between hemoglobin glycation index and cardiometabolic risk factors in Korean pediatric nondiabetic population

Purpose The hemoglobin glycation index (HGI) represents the degree of nonenzymatic glycation and has been positively associated with cardiometabolic risk factors (CMRFs) and cardiovascular disease in adults. This study aimed to investigate the association between HGI, components of metabolic syndrome (MS), and alanine aminotransferase (ALT) in a pediatric nondiabetic population. Methods Data from 3,885 subjects aged 10–18 years from the Korea National Health and Nutrition Examination Survey (2011–2016) were included. HGI was defined as subtraction of predicted glycated hemoglobin (HbA1c) from measured HbA1c. Participants were divided into 3 groups according to HGI tertile. Components of MS (abdominal obesity, fasting glucose, triglycerides, high-density lipoprotein cholesterol, and blood pressure), and proportion of MS, CMRF clustering (≥2 of MS components), and elevated ALT were compared among the groups. Results Body mass index (BMI) z-score, obesity, total cholesterol, ALT, abdominal obesity, elevated triglycerides, and CMRF clustering showed increasing HGI trends from lower-to-higher tertiles. Multiple logistic regression analysis showed the upper HGI tertile was associated with elevated triglycerides (odds ratio, 1.65; 95% confidence interval, 1.18–2.30). Multiple linear regression analysis showed HGI level was significantly associated with BMI z-score, HbA1c, triglycerides, and ALT. When stratified by sex, age group, and BMI category, overweight/obese subjects showed linear HGI trends for presence of CMRF clustering and ALT elevation. Conclusions HGI was associated with CMRFs in a Korean pediatric population. High HGI might be an independent risk factor for CMRF clustering and ALT elevation in overweight/obese youth. Further studies are required to establish the clinical relevance of HGI for cardiometabolic health in youth

Pulmonary Complication of Novel Influenza A (H1N1) Infection: Imaging Features in Two Patients

Novel influenza A (H1N1) virus is the pathogen of recent global outbreaks of febrile respiratory infection. We herein report the imaging findings of pulmonary complication in two patients with novel influenza A (H1N1) infection. The first patient without secondary infection showed the ill-defined ground-glass opacity nodules and patch areas of ground-glass opacities. The second patient with secondary pneumococcal pneumonia showed areas of lobar consolidation in the right middle lobe and left lower lobe and ground-glass opacities

Regulation of Polar Peptidoglycan Biosynthesis by Wag31 Phosphorylation in Mycobacteria

<p>Abstract</p> <p>Background</p> <p>Sensing and responding to environmental changes is a central aspect of cell division regulation. <it>Mycobacterium tuberculosis </it>contains eleven Ser/Thr kinases, two of which, PknA and PknB, are key signaling molecules that regulate cell division/morphology. One substrate of these kinases is Wag31, and we previously showed that partial depletion of Wag31 caused morphological changes indicative of cell wall defects, and that the phosphorylation state of Wag31 affected cell growth in mycobacteria. In the present study, we further characterized the role of the Wag31 phosphorylation in polar peptidoglycan biosynthesis.</p> <p>Results</p> <p>We demonstrate that the differential growth among cells expressing different <it>wag31 </it>alleles (wild-type, phosphoablative, or phosphomimetic) is caused by, at least in part, dissimilar nascent peptidoglycan biosynthesis. The phosphorylation state of Wag31 is found to be important for protein-protein interactions between the Wag31 molecules, and thus, for its polar localization. Consistent with these results, cells expressing a phosphomimetic <it>wag31 </it>allele have a higher enzymatic activity in the peptidoglycan biosynthetic pathway.</p> <p>Conclusions</p> <p>The Wag31_Mtbphosphorylation is a novel molecular mechanism by which Wag31_Mtbregulates peptidoglycan synthesis and thus, optimal growth in mycobacteria.</p

Microembolism after Endovascular Treatment of Unruptured Cerebral Aneurysms: Reduction of its Incidence by Microcatheter Lumen Aspiration

PurposeDiffusion-weighted MR images (DWI) obtained after endovascular treatment of cerebral aneurysms frequently show multiple high-signal intensity (HSI) dots. The purpose of this study was to see whether we could reduce their incidence after embolization of unruptured cerebral aneurysms by modification of our coiling technique, which involves the deliberate aspiration of the microcatheter lumen right after delivery of each detachable coil into the aneurysm sac.Materials and MethodsFrom January 2011 to June 2011, all 71 patients with unruptured cerebral aneurysms were treated using various endovascular methods. During the earlier period, 37 patients were treated using our conventional embolization technique (conventional period). Then 34 patients were treated with a modified coiling technique (modified period). DWI was obtained on the following day. We compared the occurrence of any DWI HSI lesions and the presence of the symptomatic lesions during the two time periods.ResultsThe incidence of the DWI HSI lesions differed significantly at 89.2% (33/37) during the conventional period and 26.5% (9/34) during the modified period (p < 0.0001). The incidence of symptomatic lesions differed between the two periods (29.7% during the conventional period vs. 2.9% during the modified period, p < 0.003).ConclusionAspiration of the inner content of the microcatheter right after detachable coil delivery was helpful for the reduction of the incidence of microembolisms after endovascular coil embolization for the treatment of unruptured cerebral aneurysms

The Efficacy of Postoperative Prophylactic Antibiotics in Orthognathic Surgery: A Prospective Study in Le Fort I Osteotomy and Bilateral Intraoral Vertical Ramus Osteotomy

PURPOSE: This study examined the efficacy of the postoperative prophylactic antibiotics used in orthognathic surgery. the prevalence of surgical site infections (SSIs) was determined according to the use of postoperative prophylactic antibiotics. PATIENTS and METHODS: Fifty-six patients were divided into 2 groups. Each patient intravenously received 1.0 g of a third-generation cephalosporin (Cefpiramide) 30 minutes before surgery. Among them, 28 patients in the control group received 1.0 g Cefpiramide twice daily until the third day after surgery. the postoperative wounds were examined regularly for the presence of infectious signs. RESULTS: There was no significant difference in the incidence of postoperative wound infections between patients who had received postoperative prophylactic antibiotic administration and those who had not (p = 0.639). CONCLUSION: Prolonged prophylactic antibiotic use after orthognathic surgery may not be necessary, provided that there are no other significant factors for wound infections.ope

Relationships of Basal Level of Serum 17-Hydroxyprogesterone with that of Serum Androstenedione and Their Stimulated Responses to a Low Dose of ACTH in Young Adult Patients with Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency

A single measurement of serum 17α-hydroxyprogesterone (17OHP) level can be unreliable because of its marked diurnal variation. We investigated the relationship of serum level of 17OHP with that of androstenedione (AD), which shows a smaller diurnal variation. And we tested whether the responses of these two hormones to low-dose ACTH stimulation are correlated in patients with 21-hydroxylase deficiency. Baseline serum 17OHP and AD levels were measured in 87 patients and a low-dose ACTH stimulation test was performed in 41 patients. The basal 17OHP level correlated positively with the basal AD level independently of sex, type of 21-hydroxylase deficiency, and the time of day of blood sampling (n = 87, R2 = 0.75, P < 0.001). The area under the curve of 17OHP and AD correlated positively with their respective basal levels. The fold-change increase in 17OHP after ACTH injection correlated negatively with the basal 17OHP level, but that of AD did not correlate with the basal AD level. The random serum 17OHP level, used in the clinic, is a reliable guide and a low-dose ACTH stimulation test provides no extra benefit for assessing the treatment adequacy in patients with 21-hydroxylase deficiency