AoA-based Position and Orientation Estimation Using Lens MIMO in Cooperative Vehicle-to-Vehicle Systems

Positioning accuracy is a critical requirement for vehicle-to-everything (V2X) use cases. Therefore, this paper derives the theoretical limits of estimation for the position and orientation of vehicles in a cooperative vehicle-to-vehicle (V2V) scenario, using a lens-based multiple-input multiple-output (lens-MIMO) system. Following this, we analyze the Cram$\acute{\text{e}}$r-Rao lower bounds (CRLBs) of the position and orientation estimation and explore a received signal model of a lens-MIMO for the particular angle of arrival (AoA) estimation with a V2V geometric model. Further, we propose a lower complexity AoA estimation technique exploiting the unique characteristics of the lens-MIMO for a single target vehicle; as a result, its estimation scheme is effectively extended by the successive interference cancellation (SIC) method for multiple target vehicles. Given these AoAs, we investigate the lens-MIMO estimation capability for the positions and orientations of vehicles. Subsequently, we prove that the lens-MIMO outperforms a conventional uniform linear array (ULA) in a certain configuration of a lens's structure. Finally, we confirm that the proposed localization algorithm is superior to ULA's CRLB as the resolution of the lens increases in spite of the lower complexity.Comment: 16 pages, 11 figure

Sparse RF Lens Antenna Array Design for AoA Estimation in Wideband Systems: Placement Optimization and Performance Analysis

In this paper, we propose a novel architecture for a lens antenna array (LAA) designed to work with a small number of antennas and enable angle-of-arrival (AoA) estimation for advanced 5G vehicle-to-everything (V2X) use cases that demand wider bandwidths and higher data rates. We derive a received signal in terms of optical analysis to consider the variability of the focal region for different carrier frequencies in a wideband multi-carrier system. By taking full advantage of the beam squint effect for multiple pilot signals with different frequencies, we propose a novel reconfiguration of antenna array (RAA) for the sparse LAA and a max-energy antenna selection (MS) algorithm for the AoA estimation. In addition, this paper presents an analysis of the received power at the single antenna with the maximum energy and compares it to simulation results. In contrast to previous studies on LAA that assumed a large number of antennas, which can require high complexity and hardware costs, the proposed RAA with MS estimation algorithm is shown meets the requirements of 5G V2X in a vehicular environment while utilizing limited RF hardware and has low complexity.Comment: 15 pages, 10 figure

Copy number variation at leptin receptor gene locus associated with metabolic traits and the risk of type 2 diabetes mellitus

<p>Abstract</p> <p>Background</p> <p>Recent efforts have been made to link complex human traits and disease susceptibility to DNA copy numbers. The leptin receptor (LEPR) has been implicated in obesity and diabetes. Mutations and genetic variations of <it>LEPR </it>gene have been discovered in rodents and humans. However, the association of DNA copy number variations at the <it>LEPR </it>gene locus with human complex diseases has not been reported. In an attempt to study DNA copy number variations associated with metabolic traits and type 2 diabetes mellitus (T2DM), we targeted the <it>LEPR </it>gene locus in DNA copy number analyses.</p> <p>Results</p> <p>We identified DNA copy number variations at the <it>LEPR </it>gene locus among a Korean population using genome-wide SNP chip data, and then quantified copy numbers of the E2 DNA sequence in the first two exons overlapped between <it>LEPR </it>and <it>LEPROT </it>genes by the quantitative multiplex PCR of short fluorescent fragment (QMPSF) method. Among the non-diabetic subjects (n = 1,067), lower E2 DNA copy numbers were associated with higher fasting glucose levels in men (<it>p </it>= 1.24 × 10^-7) and women (<it>p </it>= 9.45 × 10^-5), as well as higher total cholesterol levels in men (<it>p </it>= 9.96 × 10^-7). In addition, the significant association between lower E2 DNA copy numbers and lower level of postprandial 2hr insulin was evident only in non-diabetic women, whereas some obesity-related phenotypes and total cholesterol level exhibited significant associations only in non-diabetic men. Logistic regression analysis indicated that lower E2 DNA copy numbers were associated with T2DM (odds ratio, 1.92; 95% CI, 1.26~2.96; p < 0.003) in our nested case-control study. Interestingly, the E2 DNA copy number exhibited a negative correlation with LEPR gene expression, but a positive correlation with LEPROT gene expression.</p> <p>Conclusions</p> <p>This work suggests that a structural variation at the <it>LEPR </it>gene locus is functionally associated with complex metabolic traits and the risk of T2DM.</p

Hemodynamic management during off-pump coronary artery bypass surgery: a narrative review of proper targets for safe execution and troubleshooting

Off-pump coronary surgery requires mechanical cardiac displacement, which results in bi-ventricular systolic and diastolic dysfunction. Although transient, subsequent hemodynamic deterioration can be associated with poor prognosis and, in extreme cases, emergency conversion to on-pump surgery, which is associated with high morbidity and mortality. Thus, appropriate decision-making regarding whether the surgery can be proceeded based on objective hemodynamic targets is essential before coronary arteriotomy. For adequate hemodynamic management, avoiding myocardial oxygen supply-demand imbalance, which includes maintaining mean arterial pressure above 70 mmHg and preventing an increase in oxygen demand beyond the patient’s coronary reserve, must be prioritized. Maintaining mixed venous oxygen saturation above 60%, which reflects the lower limit of adequate global oxygen supply-demand balance, is also essential. Above all, severe mechanical cardiac displacement incurring compressive syndromes, which cannot be overcome by adjusting major determinants of cardiac output, should be avoided. An uncompromising form of cardiac constraint can be ruled out as long as the central venous pressure is not equal to or greater than the pulmonary artery diastolic (or occlusion) pressure, as this would reflect tamponade physiology. In addition, transesophageal echocardiography should be conducted to rule out mechanical cardiac displacement-induced ventricular interdependence, dyskinesia, severe mitral regurgitation, and left ventricular outflow tract obstruction with or without systolic motion of the anterior leaflet of the mitral valve, which cannot be tolerated during grafting. Finally, the ascending aorta should be carefully inspected for gas bubbles to prevent hemodynamic collapse caused by a massive gas embolism obstructing the right coronary ostium

Effects of intraoperative inspired oxygen fraction (FiO2 0.3 vs 0.8) on patients undergoing off-pump coronary artery bypass grafting: the CARROT multicenter, cluster-randomized trial

Background To maintain adequate oxygenation is of utmost importance in intraoperative care. However, clinical evidence supporting specific oxygen levels in distinct surgical settings is lacking. This study aimed to compare the effects of 30% and 80% oxygen in off-pump coronary artery bypass grafting (OPCAB). Methods This multicenter trial was conducted in three tertiary hospitals from August 2019 to August 2021. Patients undergoing OPCAB were cluster-randomized to receive either 30% or 80% oxygen intraoperatively, based on the month when the surgery was performed. The primary endpoint was the length of hospital stay. Intraoperative hemodynamic data were also compared. Results A total of 414 patients were cluster-randomized. Length of hospital stay was not different in the 30% oxygen group compared to the 80% oxygen group (median, 7.0 days vs 7.0 days; the sub-distribution hazard ratio, 0.98; 95% confidence interval [CI] 0.83–1.16; P = 0.808). The incidence of postoperative acute kidney injury was significantly higher in the 30% oxygen group than in the 80% oxygen group (30.7% vs 19.4%; odds ratio, 1.94; 95% CI 1.18–3.17; P = 0.036). Intraoperative time-weighted average mixed venous oxygen saturation was significantly higher in the 80% oxygen group (74% vs 64%; P < 0.001). The 80% oxygen group also had a significantly greater intraoperative time-weighted average cerebral regional oxygen saturation than the 30% oxygen group (56% vs 52%; P = 0.002). Conclusions In patients undergoing OPCAB, intraoperative administration of 80% oxygen did not decrease the length of hospital stay, compared to 30% oxygen, but may reduce postoperative acute kidney injury. Moreover, compared to 30% oxygen, intraoperative use of 80% oxygen improved oxygen delivery in patients undergoing OPCAB. Trial registration ClinicalTrials.gov (NCT03945565; April 8, 2019)

Normal Ambulatory 24-Hour Esophageal pH Values in Koreans -A Multicenter Study-

Ambulatory 24-hr esophageal pH monitoring is considered the gold standard for diagnosing gastroesophageal reflux disease. The aim of this study was to establish normal values for gastroesophageal acid exposure in healthy Koreans. Fifty healthy volunteers (24 males and 26 females; mean age, 45 yr) without reflux symptoms and without reflux esophagitis or hiatal hernia on upper endoscopy underwent ambulatory 24-hr esophageal pH monitoring after esophageal manometry. The 95th percentiles for the reflux parameters were: the percent total time pH <4, 3.7%; the percent upright time pH <4, 5.7%; the percent supine time pH <4, 1.0%; the number of reflux episodes with pH <4, 76.5; the number of reflux episodes with pH <4 for >5 min, 1.5; the duration of the longest episode, 12.5 min; and the composite score, 14.2. Age and gender were not associated with any of the pH parameters. In conclusion, physiological gastroesophageal reflux occurs in healthy Koreans. These normal esophageal pH values will provide reference data for clinical and research studies in Korea

Microflowers of Sn-Co-S derived from ultra-thin nanosheets for supercapacitor applications

Herein, for the first time, we report 3D broccoli-like microflowers of Sn-Co-S directly grown on the Ni foam (Sn-Co-S/NiF) using an easy solvothermal method for the supercapacitor application. The as-fabricated Sn-Co-S/NiF electrode possesses an ultra-high specific capacitance of 2319.3 F g−1 (specific capacity of 418.7 mAh g−1) at 5 mA cm−2 and an outstanding rate capability of 70.3 %. The optimized Co doping, and unique architecture of the electrode may be responsible for the excellent performance of the electrode. Taking benefit from the high specific capacitance and fast charge transport properties of Sn-Co-S/NiF electrode, the fabricated asymmetric supercapacitor (ASC) exhibits a large potential window of 1.7 V and outstanding cycling stability of 95.8% after 10000 cycles. Moreover, the ASC device delivers an excellent energy density of 66.9 W h kg−1 at a power density of 560.1 W kg−1 which is substantially high as compared to recently reported ASC devices. These findings confirm the potential use of Sn-Co-S/NiF in new generation energy-storage devices

Bowel Preparation for Capsule Endoscopy: A Prospective Randomized Multicenter Study

Background/Aims: The ability to visualize the small bowel mucosa by capsule endoscopy is limited. Moreover, studies involving small-bowel preparation with purgative drugs have failed to establish which preparations produce better images and higher diagnostic yields. The aim of this study was to evaluate the efficacies and diagnostic yields of different bowel preparations. Methods: A cohort of 134 patients with suspected small bowel disease was randomly assigned to 3 groups. Patients in group A (n=44) fasted for 12 h before being administered an M2A capsule (Given Imaging, Yoqneam, Israel). Patients in group B (n=45) were asked to drink two doses of 45 mL of sodium phosphate (NaP) with water during the afternoon and evening on the day before the procedure and to drink at least 2 L of water thereafter. Patients in group C (n=45) drank 2 L of a polyethylene glycol (PEG) lavage solution the evening before the procedure. Results: Overall cleansing of the small bowel was adequate in 43% of patients in group A, 77% of those in group B, and 56% of those in group C (group A vs; group B, p=0.001). Diagnoses for obscure gastrointestinal bleeding were established in 9 patients (39%) in group A, 16 patients (69%) in group B, and 14 patients (50%) in group C. No significant difference in diagnostic yield was observed between groups. Conclusions: Bowel preparation with NaP for capsule endoscopy improved small-bowel mucosal visualization when compared to 12-h overnight fasting. (Gut and Liver 2009;3:180-185)Wei W, 2008, AM J GASTROENTEROL, V103, P77, DOI 10.1111/j.1572-0241.2007.01633.xCheon JH, 2007, GUT LIVER, V1, P118van Tuyl SAC, 2007, ENDOSCOPY, V39, P1037, DOI 10.1055/s-2007-966988Ben-Soussan E, 2005, J CLIN GASTROENTEROL, V39, P381FIREMAN Z, 2005, WORLD J GASTROENTERO, V11, P5863DAI N, 2005, GASTROINTEST ENDOSC, V61, P28Viazis N, 2004, GASTROINTEST ENDOSC, V60, P534Niv Y, 2004, SCAND J GASTROENTERO, V39, P1005, DOI 10.1080/00365520410003209Fireman Z, 2004, ISRAEL MED ASSOC J, V6, P521Albert J, 2004, GASTROINTEST ENDOSC, V59, P487Pennazio M, 2004, GASTROENTEROLOGY, V126, P643, DOI 10.1053/j.gastro.2003.11.057Mylonaki M, 2003, GUT, V52, P1122Costamagna G, 2002, GASTROENTEROLOGY, V123, P999, DOI 10.1053/gast.2002.35988Lewis BS, 2002, GASTROINTEST ENDOSC, V56, P349, DOI 10.1067/mge.2002.126906Kastenberg D, 2001, GASTROINTEST ENDOSC, V54, P705Aronchick CA, 2000, GASTROINTEST ENDOSC, V52, P346

A Case Report of Carbon Monoxide Poisoning Induced Cardiomyopathy Complicated with Left Ventricular Thrombus

The heart and the brain, most oxygen-dependent organs, may be severely affected after carbon monoxide (CO) exposure. CO induced cardiotoxicity may occur as a consequence of moderate to severe CO poisoning, including angina attack, myocardial infarct, arrhythmias, and heart failure. We present a rare case of CO poisoning induced cardiomyopathy with left ventricular (LV) thrombus. It is thought that LV thrombus may have been caused severely decreased LV function with dyskinesis. After short-term anticoagulant therapy, echocardiography findings revealed complete recovery of LV dyskinesis and resolution of LV thrombus

Analysis of reports on orphan lung diseases in Korean children

PurposeOrphan lung diseases are defined as lung diseases with a prevalence of 1 or less in 2,000 individuals. Despite an increase in the numbers of patients with such diseases, few studies on Korean children have appeared. To obtain epidemiologic and demographic data on these diseases, we systematically reviewed reports on pediatric orphan lung diseases in Korea over the last 50 years.MethodsWe reviewed 223 articles that have appeared since 1958 on orphan lung diseases in Korean children. These articles described a total of 519 patients aged between 0 and 18 years. We classified patients by year of publication, diagnosis, geographic region, and journal.ResultsOf 519 patients, 401 had congenital cystic lung diseases and 66 had bronchiolitis obliterans. About 80% of patients were described in reports published in three journals, Pediatric Allergy and Respiratory Disease (Korea), the Korean Journal of Pediatrics, and the Korean Journal of Thoracic and Cardiovascular Surgery, in which papers on 157 (30.2%), 138 (26.6%), and 111 (21.4%) patients appeared, respectively. The frequency of publication of case reports has increased since 1990. Of the 519 patients, 401 (77.3%) were from Seoul/Gyeonggi-do and 72 (13.9%) from Busan/Gyeongsangnam-do.ConclusionThe prevalence of pediatric orphan lung disease has increased since 1990, and some provinces of Korea have a higher incidence of these diseases than do others. Studies exploring the incidence of pediatric orphan lung diseases in Korea are needed for effective disease management