Stochastic Channel Selection in Cognitive Radio Networks

Abstract — In this paper, we investigate the channel selection strategy for secondary users in cognitive radio networks. We claim that in order to avoid the costly channel switchings, a secondary user may desire an optimal channel which maximizes the probability of successful transmissions, rather than consis-tently adapting channels to the random environment. We propose a stochastic channel selection algorithm based on the learning automata techniques. This algorithm adjusts the probability of selecting each available channel and converges to the -optimal solution asymptotically. I

Preparation and Free Radical Detection of Doped ZnO Nanomaterials

Nanomaterials play an important role in the field of optics and medicine, and rare earth cerium can act as a catalyst and a dopant to increase improve its optical properties. Used nanometer zinc oxide as a carrier, the Ag-ZnO and Ag-Ce-ZnO samples were prepared with the sol-gel method and characterized by X-ray diffractometer. The nanometer zinc oxide materials can generate the free hydroxyl radicals, so the methylene blue solution (MB) was used as the capture agent, and the free radicals produced by the doped nanometer zinc oxide were detected by UV-spectrophotometry. The results showed that the preparation particle size of the Ag-ZnO sample was about 75nm, particle size of the Ag-Ce-ZnO sample was about 70nm. The concentration of two samples treated with the dispersant PAAS generated hydroxyl radicals is much larger than the two samples treated with the dispersant SDBS. The doping of Ce ions not only improved the optical activity of the samples, but also increased the content of hydroxyl radicals. Rare-earth doped effe ctively improved the optical properties of the ZnO nanoparticles, and the effect of sample Ag-Ce-ZnO was better than Ag-ZnO samples. Discussion and study on the nature of both the nanometer zinc oxide and doped nanometer zinc oxide, as well as the method of preparation and the theory of produce hydroxyl radicals. In the experiment, doped nano-ZnO was used as carrier and methylene blue (MB) as capture reagent. This study provided a new method for the detection of free radicals drugs

Serum klotho as a novel biomarker for metabolic syndrome: findings from a large national cohort

BackgroundMetabolic syndrome is a cluster of metabolic abnormalities that significantly increase the risk of cardiovascular disease and mortality. The identification of novel biomarkers associated with mortality in patients with metabolic syndrome could facilitate early risk stratification and targeted interventions.MethodsWe conducted a large prospective cohort study using data from five cycles (2009-2016) of the National Health and Nutrition Examination Survey (NHANES) database, including a total of 40,439 participants. Logistic regression analysis was used to assess the association between serum klotho protein levels and metabolic syndrome, while Cox regression analysis was employed to examine the correlation between serum klotho levels and all-cause mortality. Mortality data were updated until December 31, 2019.ResultsAfter adjusting for demographic and socioeconomic confounders, the logistic regression model demonstrated that higher serum klotho levels were significantly associated with a decreased prevalence of metabolic syndrome (OR [95% CI] Highest vs. lowest quartile: 0.84 [0.70-0.99], P=0.038). In the Cox regression model, elevated klotho levels were found to significantly reduce the risk of all-cause mortality among individuals with metabolic syndrome (HR [95% CI] Highest vs. lowest quartile: 0.68 [0.51-0.90], P=0.006).ConclusionSerum klotho levels were found to be inversely associated with the prevalence of metabolic syndrome, independent of potential confounding factors such as demographics, socioeconomic status, and lifestyle factors. Furthermore, higher klotho levels strongly indicated a lower risk of all-cause mortality in individuals with metabolic syndrome

Population Pharmacokinetic/Pharmacodynamic Model-Guided Dosing Optimization of a Novel Sedative HR7056 in Chinese Healthy Subjects

HR7056 is a new benzodiazepine, showing more faster acting onset and recovery than currently available short-acting sedatives. To avoid inadequate anesthesia and predict return of cognition, allowing for immediate neurological evaluation, HR7056 pharmacokinetics and pharmacodynamics were characterized in Chinese healthy subjects. We report on modeling of the data and simulations of dosage regimens for future study. Up to 63 subjects were evaluated, using Bispectral Index (BIS) and Modified Observer's Assessment of Alertness/Sedation (MOAA/S) as pharmacodynamics endpoints. A three-compartment model best described HR7056 pharmacokinetics. Total clearance was 1.49 L min−1, central volume was 2.1 L, inter-compartmental clearances were 0.96 and 0.27 L min−1, respectively. The population mean pharmacodynamic parameters were as follows: BIS, E0: 95.3; IC50: 503 ng mL−1; γ: 1.5; ke0: 0.0855 min−1; Imax: 47.9 and MOAA/S, IC50: 436 ng mL−1; γ: 1.5; ke0: 0.05 min−1; Imax: 27.9. The model simulation will enable maintenance doses to be given more accurately for future study.Clinical Trial Registration: identifier: NCT0197007

Global catalogue of microorganisms (gcm): a comprehensive database and information retrieval, analysis, and visualization system for microbial resources

Abstract Background Throughout the long history of industrial and academic research, many microbes have been isolated, characterized and preserved (whenever possible) in culture collections. With the steady accumulation in observational data of biodiversity as well as microbial sequencing data, bio-resource centers have to function as data and information repositories to serve academia, industry, and regulators on behalf of and for the general public. Hence, the World Data Centre for Microorganisms (WDCM) started to take its responsibility for constructing an effective information environment that would promote and sustain microbial research data activities, and bridge the gaps currently present within and outside the microbiology communities. Description Strain catalogue information was collected from collections by online submission. We developed tools for automatic extraction of strain numbers and species names from various sources, including Genbank, Pubmed, and SwissProt. These new tools connect strain catalogue information with the corresponding nucleotide and protein sequences, as well as to genome sequence and references citing a particular strain. All information has been processed and compiled in order to create a comprehensive database of microbial resources, and was named Global Catalogue of Microorganisms (GCM). The current version of GCM contains information of over 273,933 strains, which includes 43,436bacterial, fungal and archaea species from 52 collections in 25 countries and regions.A number of online analysis and statistical tools have been integrated, together with advanced search functions, which should greatly facilitate the exploration of the content of GCM. Conclusion A comprehensive dynamic database of microbial resources has been created, which unveils the resources preserved in culture collections especially for those whose informatics infrastructures are still under development, which should foster cumulative research, facilitating the activities of microbiologists world-wide, who work in both public and industrial research centres. This database is available from http://gcm.wfcc.info.Peer Reviewe

Structural factors controlling the spin-spin exchange coupling: EPR spectroscopic studies of highly asymmetric trityl-nitroxide biradicals

Highly asymmetric exchange-coupled biradicals, like the trityl-nitroxides (TN), possess particular magnetic properties opening new possibilities for their application in biophysical, physicochemical and biological studies. In the present work, we investigated the effect of the linker length on the spin-spin coupling interaction in TN biradicals using the newly synthesized biradicals CT02-GT, CT02-AT, CT02-VT and CT02-PPT as well as the previously reported biradicals TNN14 and TN1. Results show that the magnitude of the spin-spin interaction (J) can be easily tuned from ~ 4 G (conformer 1 in CT02-PPT) to over 1200 G (in TNN14) using various linkers separating the two radical moieties and with varying temperature. Computer simulation of EPR spectra was carried out to directly estimate J values of the TN biradicals. In addition to the spin-spin coupling interaction of TN biradicals, their g, hyperfine splitting and zero-field splitting interactions were explored at low temperature (220 K). Our present study clearly shows that the spin-spin interaction variation as a function of linker distance and temperature provides an effective strategy to develop new TN biradicals which can find wide applications in relevant fields

The research on the immuno-modulatory defect of Mesenchymal Stem Cell from Chronic Myeloid Leukemia patients

Overwhelming evidence from leukemia research has shown that the clonal population of neoplastic cells exhibits marked heterogeneity with respect to proliferation and differentiation. There are rare stem cells within the leukemic population that possess extensive proliferation and self-renewal capacity not found in the majority of the leukemic cells. These leukemic stem cells are necessary and sufficient to maintain the leukemia. While the hematopoietic stem cell (HSC) origin of CML was first suggested over 30 years ago, recently CML-initiating cells beyond HSCs are also being investigated. We have previously isolated fetal liver kinase-1-positive (Flk1+) cells carrying the BCR/ABL fusion gene from the bone marrow of Philadelphia chromosome-positive (Ph+) patients with hemangioblast property. Here, we showed that CML patient-derived Flk1+CD31-CD34-MSCs had normal morphology, phenotype and karyotype but appeared impaired in immuno-modulatory function. The capacity of patient Flk1+CD31-CD34- MSCs to inhibit T lymphocyte activation and proliferation was impaired in vitro. CML patient-derived MSCs have impaired immuno-modulatory functions, suggesting that the dysregulation of hematopoiesis and immune response may originate from MSCs rather than HSCs. MSCs might be a potential target for developing efficacious cures for CML