Diffraction Analysis and Tactical Applications of Signal Propagation over Rough Terrain

The free space propagation model is inadequate to predict the mean path-loss in ground wireless communication. Also, many existing propagation channel models do not adequately predict path-loss in rough terrain because most of them were based on measurements in urban areas. Hence, a channel model that estimates mean path-loss over many different kinds of terrain conditions is desired. In this thesis, two new propagation channel models, Real Terrain Diffraction Model (RTDMOD) and Universal Terrain Channel Model (UTCMOD), were developed. Other geometric theory of diffraction (GTD) methods (Epstein-Peterson (EP) and Deygout (DG)) agree within 5 % from 3 MHz to 3GHz with RTDMOD. However, unlike these other methods, RTDMOD can account for an almost unlimited number of obstacles and has the advantage of predicting the significant diffraction point locations as well as the total path-loss for a given set of real terrain data. The computationally efficient stochastic channel model, UTCMOD, was developed from numerous Monte Carlo simulations using RTDMOD. UTCMOD agrees within 1 dB/km over a broad carrier frequency range and a large terrain height variance range with the popular Hata model. Furthermore, UTCMOD is applicable to many different kinds of terrain conditions whereas the Hata model is most relevant for terrain conditions characteristic of large cities or medium-small cities. Unlike previous models, UTCMOD considers communication link conditions (i.e the relative heights of transmitter, receiver, and terrain peaks along the path) and provides the correct perspective for analyzing the propagation effects. Also UTCMOD can be used to optimize many tactical communication (TAC COMM) and electronic warfare (EW) scenarios for Low Probability of Interception (LPI) performance

Sleep Status and the Risk Factor of Drowsy-Related Accidents in Commercial Motor Vehicle Drivers

Background and Objective The purpose of this study was to describe prevalence of sleep problems including obstructive sleep apnea (OSA), insomnia, and sleep insufficiency in commercial motor vehicle (CMV) drivers, and to quantify risk of drowsy-related accidents in CMV drivers. Methods CMV drivers were invited to participate in this study. Participants were asked to complete a questionnaire about sleep habits, sleep disorders, work environments, and experience of drowsy-related accidents. A home sleep test (Watch-PAT 200) was also undertaken to detect OSA. Results Among 110 participants, 89 with eligible data of questionnaires and home sleep tests were included in the analysis. 91.0% of participants had OSA with peripheral arterial tonometry respiratory distress index (pRDI) ≥ 5/h and 23.6% had moderate to severe OSA with pRDI ≥ 15/h. 55.1% perceived that their sleep is insufficient. 52.3% of participants experienced drowsy driving. Drowsy driving-related motor vehicle crashes (MVCs) and near miss MVCs were reported by 9.6% and 37.9% of participants, respectively. Multiple regression analysis showed that increased risk of drowsy driving was associated with perceived sleep insufficiency [odds ratio (OR) = 3.48, 95% confidence interval (CI) 1.26–9.64]. Increased risk of drowsy driving-related near miss MVC was associated with perceived sleep insufficiency (OR = 3.06, 95% CI 1.11–8.44) and continuous driving for more than 4 hours (OR = 3.10, 95% CI 1.00–9.58). Conclusions OSA and perceived sleep insufficiency are prevalent in CMV drivers. Perceived sleep insufficiency and longer continuous driving hours increased risk of drowsy-related accidents

ACT-PRESTO: Rapid and consistent tissue clearing and labeling method for 3-dimensional (3D) imaging

Understanding the structural organization of organs and organisms at the cellular level is a fundamental challenge in biology. This task has been approached by reconstructing three-dimensional structure from images taken from serially sectioned tissues, which is not only labor-intensive and time-consuming but also error-prone. Recent advances in tissue clearing techniques allow visualization of cellular structures and neural networks inside of unsectioned whole tissues or the entire body. However, currently available protocols require long process times. Here, we present the rapid and highly reproducible ACT-PRESTO (active clarity technique-pressure related efficient and stable transfer of macromolecules into organs) method that clears tissues or the whole body within 1 day while preserving tissue architecture and protein-based signals derived from endogenous fluorescent proteins. Moreover, ACT-PRESTO is compatible with conventional immunolabeling methods and expedites antibody penetration into thick specimens by applying pressure. The speed and consistency of this method will allow high-content mapping and analysis of normal and pathological features in intact organs and bodies.1

The study of distribution characteristics of vascular and naturalized plants in Dokdo, South Korea

This study was performed to investigate the distribution of vascular plants and the characteristics of naturalized plants in Dokdo Island, South Korea. The survey was conducted a total of 5 times from June 2012 to September 2013. The number of plants confirmed in this study was 60 taxa in total: 29 families, 49 genera, 55 species, 2 subspecies and 3 varieties. To classify them by regional groups, 53 taxa were confirmed in the Dongdo and 38 taxa were confirmed in the Seodo. Among them, the distribution of Stellaria neglecta Weihe and Puccinellia nipponica Ohwi was first discovered in this study. The naturalized plants distributed in Dokdo was 7 taxa: Chenopodium album L., Sonchus asper (L.) Hill, Sonchus oleraceus L., Ipomoea purpurea Roth, Brassica juncea (L.) Czern., etc. Overall, concerns over the naturalized plants in Dokdo are high regardless of the scale of their distribution and the appearance frequency

The distribution of vascular plants in Banronsan (Mt.) at Jeongseon Gangwon-do, Korea

To study the distribution of vascular plants in Banronsan (Mt.) located in Jeongseon-gun, Gangwon-do, Korea. The vascular flora in Banronsan (Mt.) were surveyed a total of four times-three times from May 2010 to October 2010, and once in August 2012. This result revealed 447 taxa in total: 89 families, 278 genera, 390 species, four subspecies, 47 varieties, and six form. In the flora of this area, 15 taxa were Korean endemic plants including Aconitum pseudolaeve Nakai, Lysimachia coreana Nakai, and Saussurea macrolepis (Nakai) Kitam., and 17 taxa were rare and endangered plants of Korea including Astragalus koraiensis Y.N. Lee, Pseudostellaria japonica Pax, and Paeonia japonica (Makino) Miyabe and Takeda. Three taxa were found as a special forest conservation species designated by the Korea Forest Service including Delphinium maackianum Regel and Daphne pseudomezereum var. koreana (Nakai) Hamaya. Besides, 76 taxa were found to be specific floristic plants designated by the Ministry of Environment, whereas naturalized plants in this area were 32 taxa. Resource plants were categorized by usage into eight groups: 189 edible, four fiber, 127 medical, 48 ornamental, 150 pasturing, three industrial, 10 dyeing, and eight timber plants

Microtubule-associated protein 2 mediates induction of long-term potentiation in hippocampal neurons

Microtubule-associated protein (MAP) 2 has been perceived as a static cytoskeletal protein enriched in neuronal dendritic shafts. Emerging evidence indicates dynamic functions for various MAPs in activity-dependent synaptic plasticity. However, it is unclear how MAP2 is associated with synaptic plasticity mechanisms. Here, we demonstrate that specific silencing of high-molecular-weight MAP2 in vivo abolished induction of long-term potentiation (LTP) in the Schaffer collateral pathway of CA1 pyramidal neurons and in vitro blocked LTP-induced surface delivery of AMPA receptors and spine enlargement. In mature hippocampal neurons, we observed rapid translocation of a subpopulation of MAP2, present in dendritic shafts, to spines following LTP stimulation. Time-lapse confocal imaging showed that spine translocation of MAP2 was coupled with LTP-induced spine enlargement. Consistently, immunogold electron microscopy revealed that LTP stimulation of the Schaffer collateral pathway promoted MAP2 labeling in spine heads of CA1 neurons. This translocation depended on NMDA receptor activation and Ras-MAPK signaling. Furthermore, LTP stimulation led to an increase in surface-expressed AMPA receptors specifically in the neurons with MAP2 spine translocation. Altogether, this study indicates a novel role for MAP2 in LTP mechanisms and suggests that MAP2 participates in activity-dependent synaptic plasticity in mature hippocampal networks. © 2020 The Authors.1

Assessment of acute, 14-day, and 13-week repeated oral dose toxicity of Tiglium seed extract in rats

Abstract Background Seed of mature Croton tiglium Linne, also known as Tiglium seed (TS), has been widely used as a natural product due to its several health beneficial properties including anti-tumor and antifungal activities. Despite its ethnomedicinal beneficial properties, toxicological information regarding TS extract, especially its long-term toxicity, is currently limited. Therefore, the objective of the present study was to evaluate acute and subchronic toxicity of TS extract in rats after oral administration following test guidelines of the Organization for Economic Cooperation and Development (OECD). Methods Toxicological properties of TS extract were evaluated by toxicity assays to determine its single-dose acute toxicity (125, 250, 500, 1000, or 2000 mg/kg), 14-day repeated-dose toxicity (125, 250, 500, 1000, or 2000 mg/kg) and 13-week repeated-dose toxicity (31.25, 62.5, 125, 250, and 500 mg/kg) in Sprague-Dawley rats and F344 rats. Hematological, serum biochemical, and histopathological parameters were analyzed to determine its median lethal dose (LD50) and no-observed-adverse-effect-level (NOAEL). Results Oral single dose up to 2000 mg/kg of TS extract resulted in no mortalities or abnormal clinical signs. In 13-week toxicity study, TS extract exhibited no dose-related changes (mortality, body weight, food/water consumption, hematology, clinical biochemistry, organ weight, or histopathology) at dose up to 500 mg/kg, the highest dosage level suggested based on 14-day repeat-dose oral toxicity study. Conclusion Acute oral LD50 of TS extract in rats was estimated to be greater than 2000 mg/kg. NOAEL of TS extract administered orally was determined to be 500 mg/kg/day in both male and female rats. Results from these acute and subchronic toxicity assessments of TS extract under Good Laboratory Practice regulations indicate that TS extract appears to be safe for human consumption

Biosynthesis of poly(2-hydroxybutyrate-co-lactate) in metabolically engineered Escherichia coli

We have previously reported in vivo biosynthesis of polyhydroxyalkanoates containing 2-hydroxyacid monomers such as lactate and 2-hydroxybutyrate in recombinant Escherichia coli strains by the expression of evolved Clostridium propionicum propionyl-CoA transferase (PctCp) and Pseudomonas sp. MBEL 6-19 polyhydroxyalkanoate (PHA) synthase 1 (PhaC1). Here, we report the biosynthesis of poly(2-hydroxybutyrate-co-lactate)[P(2HB-co-LA)] by direct fermentation of metabolically engineered E. coli strain. Among E. coli strains WL3110, XL1-Blue, and BL21(DE3), recombinant E. coli XL1-Blue strain expressing PhaC1437 and Pct540 produced P(76.4mol%2HB-co-23.6mol%LA) to the highest content of 88 wt% when it was cultured in a chemically defined medium containing 20 g/L of glucose and 2 g/L of sodium 2-hydroxybutyrate. When recombinant E. coli XL1-Blue strain expressing PhaC1437 and Pct540 was cultured in a chemically defined medium containing 20 g/L of glucose and varying concentration of sodium 2-hydroxybutyrate, 2HB monomer fraction in P(2HB-co-LA) increased proportional to the concentration of sodium 2-hydroxybutyrate added to the culture medium. P(2HB-co-LA)] could also be produced from glucose as a sole carbon source without sodium 2-hydroxybutyrate into the culture medium. Recombinant E. coli XL1-Blue strain expressing the phaC1437, pct540, cimA3.7, and leuBCD genes together with the L. lactis Il1403 panE gene, successfully produced P(23.5mol%2HB-co-76.5mol%LA)] to the polymer content of 19.4 wt% when it cultured in a chemically defined medium containing 20 g/L of glucose. The metabolic engineering strategy reported here should be useful for the production of novel copolymer P(2HB-co-LA)]