Responsive Polymer Grafts for Patternable Self-Oscillating Gel

Materials that can mimic biological behavior by converting chemical energy to mechanical work under constant external conditions represent an exciting opportunity for extending traditional responsive behavior via energy harvesting and autonomous function. One such material is the self-oscillating gel which exhibits periodic swell-deswell oscillations driven by the Belousov-Zhabotinsky reaction. A key step in increasing the functionality of these materials is the ability to form arrays of individual oscillators that can behave in a cooperative fashion. To achieve this ability the gel must be patternable while maintaining enough versatility to design its polymer backbone for optimal performance (e.g. maximum swell-deswell amplitudes). To address this challenge we explored the synthesis of vinyl terminated responsive polymer grafts. By incorporating these grafts into a nonresponsive polymer backbone at sufficient concentrations and applying an appropriate stimulation, the grafts should form microdomains (physical cross links between chains), enabling printing of any desired gel pattern. Poly-N-isopropylacrylamide (PNIPAm) was chosen as a test candidate due to its extensively studied thermo-responsive behavior. PNIPAm grafts with vinyl end group were made first by adding a primary amine group at one chain end using 2-aminoethanethiol as a chain transfer reagent during radical polymerization. Then the amine end-group was replaced with a vinyl group using an amide condensation reaction. Future work will involve the incorporation of this graft into various polymer backbones and exploring techniques for chemically fixing the networks after physical gelation

Improved Real-Time Monocular SLAM Using Semantic Segmentation on Selective Frames

Monocular simultaneous localization and mapping (SLAM) is emerging in advanced driver assistance systems and autonomous driving, because a single camera is cheap and easy to install. Conventional monocular SLAM has two major challenges leading inaccurate localization and mapping. First, it is challenging to estimate scales in localization and mapping. Second, conventional monocular SLAM uses inappropriate mapping factors such as dynamic objects and low-parallax areas in mapping. This paper proposes an improved real-time monocular SLAM that resolves the aforementioned challenges by efficiently using deep learning-based semantic segmentation. To achieve the real-time execution of the proposed method, we apply semantic segmentation only to downsampled keyframes in parallel with mapping processes. In addition, the proposed method corrects scales of camera poses and three-dimensional (3D) points, using estimated ground plane from road-labeled 3D points and the real camera height. The proposed method also removes inappropriate corner features labeled as moving objects and low parallax areas. Experiments with eight video sequences demonstrate that the proposed monocular SLAM system achieves significantly improved and comparable trajectory tracking accuracy, compared to existing state-of-the-art monocular and stereo SLAM systems, respectively. The proposed system can achieve real-time tracking on a standard CPU potentially with a standard GPU support, whereas existing segmentation-aided monocular SLAM does not

Temperature-dependent evolutions of excitonic superfluid plasma frequency in a srong excitonic insulator candidate, Ta2_2NiSe5_5

We investigate an interesting anisotropic van der Waals material, Ta$_{2}$NiSe$_{5}$, using optical spectroscopy. Ta$_{2}$NiSe$_{5}$ has been known as one of the few excitonic insulators proposed over 50 years ago. Ta$_{2}$NiSe$_{5}$ has quasi-one dimensional chains along the $a$-axis. We have obtained anisotropic optical properties of a single crystal Ta$_{2}$NiSe$_{5}$ along the $a$- and $c$-axes. The measured $a$- and $c$-axis optical conductivities exhibit large anisotropic electronic and phononic properties. With regard to the $a$-axis optical conductivity, a sharp peak near 3050 cm$^{-1}$ at 9 K, with a well-defined optical gap ($\Delta^{EI} \simeq$ 1800 cm$^{-1}$) and a strong temperature-dependence, is observed. With an increase in temperature, this peak broadens and the optical energy gap closes around $\sim$325 K($T_c^{EI}$). The spectral weight redistribution with respect to the frequency and temperature indicates that the normalized optical energy gap ($\Delta^{EI}(T)/\Delta^{EI}(0)$) is $1-(T/T_c^{EI})^2$. The temperature-dependent superfluid plasma frequency of the excitonic condensation in Ta$_{2}$NiSe$_{5}$ has been determined from measured optical data. Our findings may be useful for future research on excitonic insulators.Comment: 17 pages, 5 figure

The association between new graphic health warning labels on tobacco products and attitudes toward smoking among south Korean adolescents: a national cross-sectional study

Background Graphic health warning labels (GHWLs) on tobacco products are more effective than text warnings for communicating the risk of smoking. The implementation of GHWLs can prevent adolescents from initiating smoking. Therefore, this study examined the association between GHWLs newly implemented on December 23, 2016, in South Korea and attitudes toward smoking among adolescents. Methods This post-implementation cross-sectional analysis examined the responses of 62,276 students (31,624 boys and 30,652 girls) who participated in the 2017 Web-based Korean Youth Risk Behavior Survey, which was completed anonymously as a self-administered questionnaire by middle and high school students. Multinomial logistic regression was applied to explore the attitudes toward smoking among the youth (13–18 years old) who have been exposed to GHWLs in order to identify relationship of exposure to the GHWLs with smoking initiation and awareness of the danger of smoking. Results Six months after implementation, 69.4% of adolescents reported having been exposed to GHWLs in the previous 30 days. Among those exposed to GHWLs both boys and girls in grade 7 were significantly more likely than grade 12 high school students to decide not to start smoking (boys: AOR = 3.96, 95% CI 3.31–4.75, p < 0.001; girls: AOR = 2.76, 95% CI 2.32–3.30, p < 0.001) and to think that smoking was dangerous to their health (boys: AOR = 3.01, 95% CI 2.52–3.58, p < 0.001; girls: AOR = 2.42, 95% CI 2.03–3.88, p < 0.001) after seeing GHWLs. These associations were greater for adolescents who had experienced smoking-prevention education or had been exposed to anti-tobacco advertisements. However, those who smoked, used e-cigarettes, or experienced secondhand smoking were significantly less likely to decide not to smoke and to view smoking as dangerous. Conclusions To maintain the perception of the harm of tobacco from childhood through adolescence, the government should implement both comprehensive tobacco controls, including smoking-prevention education in schools, and measures to encourage a smoke-free environment in homes.This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. 2020R1C1C1012562)

Taxonomy and Evaluations of Low-Power Listening Protocols for Machine-to-Machine Networks

Even though a lot of research has made significant contributions to advances in sensor networks, sensor network protocols, which have different characteristics according to the target application, might confuse machine-to-machine (M2M) network designers when they choose the protocol most suitable for their specific applications. Therefore, this paper provides a well-defined taxonomy of low-power listening protocols by examining in detail the existing low-power sensor network protocols and evaluation results. It will also be very useful for helping M2M designers understand specific features of low-power media access control protocols as they design new M2M networks

Improving Neural Radiance Field using Near-Surface Sampling with Point Cloud Generation

Neural radiance field (NeRF) is an emerging view synthesis method that samples points in a three-dimensional (3D) space and estimates their existence and color probabilities. The disadvantage of NeRF is that it requires a long training time since it samples many 3D points. In addition, if one samples points from occluded regions or in the space where an object is unlikely to exist, the rendering quality of NeRF can be degraded. These issues can be solved by estimating the geometry of 3D scene. This paper proposes a near-surface sampling framework to improve the rendering quality of NeRF. To this end, the proposed method estimates the surface of a 3D object using depth images of the training set and sampling is performed around there only. To obtain depth information on a novel view, the paper proposes a 3D point cloud generation method and a simple refining method for projected depth from a point cloud. Experimental results show that the proposed near-surface sampling NeRF framework can significantly improve the rendering quality, compared to the original NeRF and a state-of-the-art depth-based NeRF method. In addition, one can significantly accelerate the training time of a NeRF model with the proposed near-surface sampling framework.Comment: 13 figures, 2 table

Antidiabetic Effect of Fresh Nopal ( Opuntia ficus-indica

The objective of the present study was to evaluate α-glucosidase inhibitory and antidiabetic effects of Nopal water extract (NPWE) and Nopal dry power (NADP) in low-dose streptozotocin- (STZ-) induced diabetic rats fed a high-fat diet (HFD). The type 2 diabetic rat model was induced by HFD and low-dose STZ. The rats were divided into four groups as follows: (1) nondiabetic rats fed a regular diet (RD-Control); (2) low-dose STZ-induced diabetic rats fed HFD (HF-STZ-Control); (3) low-dose STZ-induced diabetic rats fed HFD and supplemented with NPWE (100 mg/kg body weight, HF-STZ-NPWE); and (4) low-dose STZ-induced diabetic rats fed HFD and supplemented with comparison medication (rosiglitazone, 10 mg/kg, body weight, HF-STZ-Rosiglitazone). In results, NPWE and NADP had IC50 values of 67.33 and 86.68 μg/mL, both of which exhibit inhibitory activities but lower than that of acarbose (38.05 μg/mL) while NPWE group significantly decreased blood glucose levels compared to control and NPDP group on glucose tolerance in the high-fat diet fed rats model (P<0.05). Also, the blood glucose levels of HR-STZ-NPWE group were significantly lower (P<0.05) than HR-STZ-Control group on low-dose STZ-induced diabetic rats fed HFD. Based on these findings, we suggested that NPWE could be considered for the prevention and/or treatment of blood glucose and a potential use as a dietary supplement

Clinical effectiveness of omental transposition in facilitating perineal wound healing after abdominoperineal resection: a systematic review

Background Omental transposition has been used to facilitate perineal wound healing in patients undergoing abdominoperineal resection (APR). However, there is no high-level evidence supporting the effectiveness of omental transposition in this regard. This study aimed to investigate the clinical efficacy of omental transposition in facilitating perineal wound healing after APR. Methods In this systematic review, we systematically searched the PubMed/MEDLINE, Embase, Scopus, Cochrane Library, and Web of Science databases for literature regarding the topic of our study. Studies published since the inception of each database were considered for review. The outcomes of interest were the perineal wound healing rate at 1 and 3 months postoperatively, perineal wound infection rate, and perineal wound healing period. Results Of the 1,923 studies identified, four articles representing 819 patients (omental transposition patients, n=295) were included in the final analysis. The wound healing rates at 1 and 3 months postoperatively in the omental transposition group (68.5% and 79.7%, respectively) did not significantly differ from those in the control group (57.4% and 78.7%, respectively) (p=0.759 and p=0.731, respectively). Perineal wound infection and chronic wound complication rates, including sinus, dehiscence, and fistula rates, also did not significantly differ between the omental transposition (8% and 7%, respectively) and control (11% and 7%, respectively) groups (p=0.221 and p=0.790, respectively). Conclusion Our results suggest that omental transposition does not affect perineal wound healing in patients who undergo APR

Prevalence and predictors of heated tobacco products use among male ever smokers: results from a Korean longitudinal study

Background This study examined sociodemographic and tobacco-related factors of heated tobacco products (HTPs) use among adult ever smokers in South Korea where the sales of HTPs have been rapidly increasing since their launch in June 2017. Methods Before the launch of HTPs in Korea, participants comprised male ever smokers (234 current smokers and 37 quitters) who participated in the Korea National Health and Nutrition Examination Survey from 2015 to 2017 through one-to-one interview survey and agreed to participate in the follow-up surveys through telephone in December 2017. Data were analyzed using logistic regression, to explore sociodemographic and smoking behavior-related factors of HTPs use. Results Overall, 10.7% (29/271) of participants responded to using HTPs and 8.1% (22/271) were current HTPs users at the time of the follow-up survey. Multivariate analysis showed that HTPs use is associated with middle age (36 to 49 years old) (aOR = 3.72, CI = 1.16–12.0) (vs. ≥ 50 years), higher income (4Q vs 1Q: aOR = 2.71, CI = 1.16–6.34), and higher educational level (college or higher: aOR = 2.40, CI = 0.87–6.60). Also, vaping experience at baseline was highly associated with HTPs use (aOR = 3.11, CI = 1.22–7.93 for the former experience; aOR = 9.14, CI = 2.34–35.6 for current). However, smoking amount and level of motivation for smoking cessation were not found to be predictors of future HTPs use when limited to current smokers at baseline. Conclusions The results showed that vaping experience regardless of current smoking behavior and higher socioeconomic status were found to be associated with subsequent HTPs use among ever smokers. Further studies are required to explore whether this association is causal.This work was supported by the Korea Centers for Disease Control and Prevention (grant numbers 2017-E34011–00). The funding bodies had no role in the design of the study, data collection, analysis and interpretation of data, and writing of the manuscript