No abstract

No abstract

No abstract

A novel technique to design a wideband implantable antenna has been proposed by using magneto-dielectric material. The antenna is a half cutting of a coplanar waveguide fed antenna with symmetric geometry printed on a flexible substrate with 24 µm thickness. A piece of magneto-dielectric sheet with 0.25 mm thickness is attached on the bottom layer of the antenna to tune the antenna bandwidth. The antenna is simulated in a one-layer body phantom. Simulation shows that the antenna has a wide bandwidth covering 902-928 MHz Industrial, Scientific, and Medical (ISM) band when the body phantom is filled with muscle. There are frequency bandwidth shifts when the body phantom is filled with different tissues of skin, small intestine, and stomach, respectively. The antenna has wide bandwidth covering ISM band in these tissues. Measurement has been done in meat mince. The measured bandwidth of proposed antenna is 810-1062 MHz. The proposed antenna has a compact size of 4 mm × 12 mm × 0.274 mm suitable to be applied in capsule endoscope, wireless pacemaker, etc. 1. INTRODUCTION Implantable biomedical devices using wireless communication have attracted much research interest in medical area due to virtues of live signal transmission and less pain to patient. These devices include wireless capsule endoscope, wireless cardiac pacemaker, glucose monitoring system, neural recording system, etc. [1-5]. Implantable antenna is an important component of an implantable wireless biomedical device to transfer data between inner body and outside body. Implantable antennas are required with miniaturized volume to reduce the physical uncomfortableness caused by the implantation inside body. The size of an ordinary antenna is inversely proportional to its working frequency. The popularly used frequency bands of implantable devices include Industrial, Scientific, and Medical (ISM, 433.05-434.79 MHz, 902-928 MHz, and 2.4-2.4835 GHz) bands, Medical Implant Communication Services (MICS, 402-405 MHz), Ultra-Wideband (UWB, 3.1-10.6 GHz)). It is easy to design a small antenna at UWB and ISM 2.4 GHz bands. However, the human body would absorb more energy with increase of frequency when electromagnetic waves propagate inside human body. Bands of ISM 2.4 and UWB with higher frequency are difficult to transfer high quality signals. Lower bands of ISM 433 MHz and MICS with narrow frequency bands of 1.74 MHz and 3 MHz, respectively, are difficult to obtain high data rate. Therefore, ISM 902-928 MHz band is a promising band to transfer high data rate signal for implantable devises [1, 3]. Many research works have been done on compact implantable antenna design [1, 2, 4-12]. Conventional miniaturization techniques are adopted including etching slots on patch [2, 4, 5], using multiple layer stacked structure [6, 7], and meandering strip/line in folded or helical shape [1, 4, 5, 8-12]. Dielectric, magnetic, and magneto-dielectric (MD) materials with high permittivity or permeability are also used as substrates to obtain antenna size reduction [13, 14].

No abstract

The tree diameter at breast height (DBH) is one of the most important variables for monitoring the forest ecology. Mobile laser scanning (MLS), which has been widely applied in the forestry field, makes DBH measurement fast and convenient. However, there are many shrubs and deadwood in the neutral forest environment and the point clouds quality from MLS are easily affected by the environment which results in low single tree segmentation and DBH estimation accuracy. To improve the accuracy in a complex forest environment and low point cloud quality, we propose a relative density segmentation method for the single tree segmentation and DBH estimation method based on multi-height diameters for the DBH estimation. The relative density segmentation method calculates the relative density according to the ratio of density in two different scales, and segments the tree trunks by the higher relative density of trunk point clouds compared with their surroundings points. In the natural forest plot, the precision and recall of the proposed segmentation method reached 0.966 and 0.946, respectively; In the urban forest plot, the precision and recall reached 1 and 0.966, respectively. The proposed DBH estimation method was used to estimate the DBH of trees using multi-height diameters. The multi-height diameters combined with the outlier detection algorithm were able to improve the accuracy and robustness when the trunk point clouds have large noise. For the DBH estimation results, the mean absolute error (MAE), mean absolute percentage error (MAPE), and root mean square error (RMSE) were 2.5 cm, 11.54%, and 3.17 cm, respectively, in the natural forest plot and 1.65 cm, 6.31%, and 1.97 cm, respectively, in the urban forest plot. The good experiment results indicate that the proposed method can achieve accurate and robust DBH extraction and provide fundamental data for supervision and sustainable development of forest resources.

ObjectiveGlucagon-like peptide-1 receptor agonists (GLP-1 RAs) have significantly improved clinical effects on glycemic control. However, real-world data concerning the difference in gastrointestinal adverse events (AEs) among different GLP-1 RAs are still lacking. Our study aimed to characterize and compare gastrointestinal AEs among different marketed GLP-1 RAs (exenatide, liraglutide, dulaglutide, lixisenatide, and semaglutide) based on real-world data.MethodsDisproportionality analysis was used to evaluate the association between GLP-1 RAs and gastrointestinal adverse events. Data were extracted from the US FDA Adverse Event Reporting System (FAERS) database between January 2018 and September 2022. Clinical characteristics, the time-to-onset, and the severe proportion of GLP-1 RAs-associated gastrointestinal AEs were further analyzed.ResultsA total of 21,281 reports of gastrointestinal toxicity were analyzed out of 81,752 adverse event reports, and the median age of the included patients was 62 (interquartile range [IQR] 54–70) years old. Overall GLP-1 RAs were associated with increased risk of gastrointestinal system disorders (ROR, 1.46; 95% CI, 1.44–1.49), which were further attributed to liraglutide (ROR, 2.39; 95% CI, 2.28–2.51), dulaglutide (ROR, 1.39; 95% CI, 1.36-1.42), and semaglutide (ROR, 3.00; 95% CI, 2.89–3.11). Adverse events uncovered in the labels included gastroesophageal reflux disease, gastritis, bezoar, breath odor, intra-abdominal hematoma, etc. Furthermore, it was observed that semaglutide had the greatest risk of nausea (ROR, 7.41; 95% CI, 7.10–7.74), diarrhea (ROR, 3.55; 95% CI, 3.35–3.77), vomiting (ROR, 6.67; 95% CI, 6.32–7.05), and constipation (ROR, 6.17; 95% CI, 5.72–6.66); liraglutide had the greatest risk of abdominal pain upper (ROR, 4.63; 95% CI, 4.12–5.21) and pancreatitis (ROR, 32.67; 95% CI, 29.44–36.25). Most gastrointestinal AEs tended to occur within one month. Liraglutide had the highest severe rate of gastrointestinal AEs (23.31%), while dulaglutide had the lowest, with a severe rate of 12.29%.ConclusionGLP-1 RA were significantly associated with gastrointestinal AEs, and the association was further attributed to liraglutide, dulaglutide, and semaglutide. In addition, semaglutide had the greatest risk of nausea, diarrhea, vomiting, constipation, and pancreatitis, while liraglutide had the greatest risk of upper abdominal pain. Our study provided valuable evidence for selecting appropriate GLP-1 RAs to avoid the occurrence of GLP-1 RA-induced gastrointestinal AEs.

No abstract