Statistical Analysis of Radio Propagation Channel in Ruins Environment

The cellphone based localization system for search and rescue in complex high density ruins has attracted a great interest in recent years, where the radio channel characteristics are critical for design and development of such a system. This paper presents a spatial smoothing estimation via rotational invariance technique (SS-ESPRIT) for radio channel characterization of high density ruins. The radio propagations at three typical mobile communication bands (0.9, 1.8, and 2 GHz) are investigated in two different scenarios. Channel parameters, such as arrival time, delays, and complex amplitudes, are statistically analyzed. Furthermore, a channel simulator is built based on these statistics. By comparison analysis of average excess delay and delay spread, the validation results show a good agreement between the measurements and channel modeling results

Natural plant polyphenols for alleviating oxidative damage in man: Current status and future perspectives

The balance between oxidation and reduction is important for maintaining a healthy biological system. Oxidative stress results from an imbalance between excessive formation of reactive oxygen species (ROS) and/or reactive nitrogen species (RNS) and limited endogenous defense systems, and this imbalance can adversely alter lipids, proteins and DNA, causing a number of human diseases. Thus, exogenous antioxidants that can neutralize the effect of free radicals are needed to diminish the cumulative effects of oxidative damage over human life span. Current research reveals that phenolic compounds in plants possess high antioxidant activity and free radical scavenging capacity and can prevent the body from oxidative damage over human life span. This review focuses on the present understanding of free radicals and antioxidants and their importance in human health and disease. Information about the chemical features of free radicals as well as their deleterious effects on cell structures is reviewed. The chemical structure and anti-oxidative mechanisms of essential polyphenols and their potential health benefits are presented. In addition, the limitation of natural antioxidants and a perspective on likely future trends in this field are also discussed.Keywords: Free radicals, Oxidative stress, Natural antioxidants, Polyphenols, Health benefits, Reactive oxygen species, Reactive nitrogen specie

Habitat adaptation drives speciation of a Streptomyces species with distinct habitats and disparate geographic origins

Microbial diversification is driven by geographic and ecological factors, but how the relative importance of these factors varies among species, geographic scales, and habitats remains unclear. Streptomyces, a genus of antibiotic-producing, spore-forming, and widespread bacteria, offers a robust model for identifying the processes underlying population differentiation. We examined the population structure of 37 Streptomyces olivaceus strains isolated from various sources, showing that they diverged into two habitat-associated (free-living and insect-associated) and geographically disparate lineages. More frequent gene flow within than between the lineages confirmed genetic isolation in S. olivaceus. Geographic isolation could not explain the genetic isolation; instead, habitat type was a strong predictor of genetic distance when controlling for geographic distance. The identification of habitat-specific genetic variations, including genes involved in regulation, resource use, and secondary metabolism, suggested a significant role of habitat adaptation in the diversification process. Physiological assays revealed fitness trade-offs under different environmental conditions in the two lineages. Notably, insect-associated isolates could outcompete free-living isolates in a free-iron-deficient environment. Furthermore, substrate (e.g., sialic acid and glycogen) utilization but not thermal traits differentiated the two lineages. Overall, our results argue that adaptive processes drove ecological divergence among closely related streptomycetes, eventually leading to dispersal limitation and gene flow barriers between the lineages. S. olivaceus may best be considered a species complex consisting of two cryptic species.China Ocean Mineral Resources R&D Association/[DY135-B2-02]/CONRA/ChinaNational Natural Science Foundation of China/[32070001 and 91751118]/NSFC/ChinaRV KEXUE/[KEXUE2019GZ05]//ChinaChinese Academy of Sciences/[KEXUE2019GZ05]/CAS/ChinaUniversidad de Costa Rica/[801-B0-530]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Estructuras Microscópicas (CIEMIC)UCR::Vicerrectoría de Docencia::Ingeniería::Facultad de Ingeniería::Escuela de Ciencias de la Computación e Informátic

Surface microstructures and corrosion resistance of Ni-Ti-Nb shape memory thin films

Ni-Ti-Nb and Ni-Ti shape memory thin films were sputter-deposited onto silicon substrates and annealed at 600ºC for crystallization. X-ray diffraction (XRD) measurements indicated that all of the annealed Ni-Ti-Nb films were composed of crystalline Ni-Ti (Nb) and Nb-rich grains. X-ray photoelectron spectroscopy (XPS) tests showed that the surfaces of Ni-Ti-Nb films were covered with Ti oxides, NiO and Nb2O5. The corrosion resistance of the Ni-Ti-Nb films in 3.5 wt. % NaCl solution was investigated using electrochemical tests such as open-circuit potential (OCP) and potentio-dynamic polarization tests. Ni-Ti-Nb films showed higher OCPs, higher corrosion potentials (Ecorr) and lower corrosion current densities (icorr) than the binary Ni-Ti film, which indicated a better corrosion resistance. The reason may be that Nb additions modified the passive layer on the film surface. The OCPs of Ni-Ti-Nb films increased with further Nb additions, whereas no apparent difference of Ecorr and icorr was found among the Ni-Ti-Nb films

Stem hydraulic traits and leaf water-stress tolerance are co-ordinated with the leaf phenology of angiosperm trees in an Asian tropical dry karst forest

Background and Aims The co-occurring of evergreen and deciduous angiosperm trees in Asian tropical dry forests on karst substrates suggests the existence of different water-use strategies among species. In this study it is hypothesized that the co-occurring evergreen and deciduous trees differ in stem hydraulic traits and leaf water relationships, and there will be correlated evolution in drought tolerance between leaves and stems. † Methods A comparison was made of stem hydraulic conductivity, vulnerability curves, wood anatomy, leaf life span, leaf pressure -volume characteristics and photosynthetic capacity of six evergreen and six deciduous tree species co-occurring in a tropical dry karst forest in south-west China. The correlated evolution of leaf and stem traits was examined using both traditional and phylogenetic independent contrasts correlations. † Key Results It was found that the deciduous trees had higher stem hydraulic efficiency, greater hydraulically weighted vessel diameter (D h ) and higher mass-based photosynthetic rate (A m ); while the evergreen species had greater xylem-cavitation resistance, lower leaf turgor-loss point water potential (p 0 ) and higher bulk modulus of elasticity. There were evolutionary correlations between leaf life span and stem hydraulic efficiency, A m , and dry season p 0 . Xylem-cavitation resistance was evolutionarily correlated with stem hydraulic efficiency, D h , as well as dry season p 0 . Both wood density and leaf density were closely correlated with leaf water-stress tolerance and A m . † Conclusions The results reveal the clear distinctions in stem hydraulic traits and leaf water-stress tolerance between the co-occurring evergreen and deciduous angiosperm trees in an Asian dry karst forest. A novel pattern was demonstrated linking leaf longevity with stem hydraulic efficiency and leaf water-stress tolerance. The results show the correlated evolution in drought tolerance between stems and leaves

Omics Insights into Metabolic Stress and Resilience of Rats in Response to Short-term Fructose Overfeeding.

SCOPE:Considerable evidence supports the view that high-fructose intake is associated with increased and early incidence of obesity and dyslipidemia. However, knowledge on physiopathological alterations introduced by fructose overconsumption is lacking. We have therefore carried out an integrated omics analysis to investigate the consequences of short-term fructose overfeeding(SFO) and identify the underlying molecular mechanisms. METHODS AND RESULTS:SFO of rats demonstrated obvious histopathological hepatic lipid accumulation and significant elevation in adiposity, total cholesterol and fasting plasma glucose levels. Integrated omics analysis demonstrated that SFO disturbed metabolic homeostasis and initiated metabolic stress. Hepatic lipogenesis pathways were also negatively impacted by SFO. Analysis of molecular networks generated by IPA implicated involvement of the ERK signaling pathway in SFO and its consequences. Moreover, we identified that an inherent negative feedback regulation of hepatic SREBP1 plays an active role in regulating hepatic de novo lipogenesis. CONCLUSION:Our findings indicate that SFO disturbs metabolic homeostasis and that endogenous small molecules positively mediate SFO induced metabolic adaption. Our results also underline that an inherent regulatory mechanism of resilience occurs in response to fructose overconsumption, suggesting that efforts to maintain resilience could be a promising target to prevent and treat metabolic disorder-like conditions. This article is protected by copyright. All rights reserved

A novel scoring system for the quantitative prediction of prognosis in acute myeloid leukemia

BackgroundAcute myeloid leukemia (AML) is a heterogeneous hematopoietic malignancy. Patient prognosis cannot be accurately assessed in National Comprehensive Cancer Network (NCCN) risk stratification subgroups based on the current criteria. This study aimed to develop a novel prognostic score model for the quantitative prediction of prognosis in AML.ResultsWe developed a prognostic risk scoring model of AML using differentially expressed genes to predict prognosis in patients with AML. Furthermore, we evaluated the effectiveness and clinical significance of this prognostic model in 4 AML cohorts and 905 patients with AML. A prognostic risk scoring model of AML containing eight prognosis-related genes was constructed using a multivariate Cox regression model. The model had a higher predictive value for the prognosis of AML in the training and validation sets. In addition, patients with lower scores had significantly better overall survival (OS) and even-free survival (EFS) than those with higher scores among patients with intermediate-risk AML according to the NCCN guidelines, indicating that the model could be used to further predict the prognosis of the intermediate-risk AML populations. Similarly, patients with high scores had remarkably poor OS and EFS in the normal-karyotype populations, indicating that the scoring model had an excellent predictive performance for patients with AML having normal karyotype.ConclusionsOur study provided an individualized prognostic risk score model that could predict the prognosis of patients with AML