Global dynamics of an age‐structured virus model with saturation effects

An infection‐age virus dynamics model for human immunodeficiency virus (or hepatitis B virus) infections with saturation effects of infection rate and immune response is investigated in this paper. It is shown that the global dynamics of the model is completely determined by two critical values R ₀, the basic reproductive number for viral infection, and R ₁, the viral reproductive number at the immune‐free infection steady state (R ₁<R ₀). If R ₀<1, the uninfected steady state E ⁰ is globally asymptotically stable; if R ₀>1 > R ₁, the immune‐free infected steady state E ^? is globally asymptotically stable; while if R ₁>1, the antibody immune infected steady state is globally asymptotically stable. Moreover, our results show that ignoring the saturation effects of antibody immune response or infection rate will result in an overestimate of the antibody immune reproductive number. Copyright © 2016 John Wiley & Sons, Ltd.     

Two Zn(II)‐based meta‐organic frameworks: Selective detection of antibiotics and treatment activity on age‐related macular degeneration by reducing inflammasome activation

Via utilizing the mixed‐ligand method, two novel Zn(II)‐containing meta‐organic frameworks with the chemical formula of {[Zn(L)(5‐HIP)]·H₂O}_n ( 1 ) and [Zn(L)(2,6‐NDC)]_n ( 2 ) were prepared under the solvothermal conditions by applying aromatic dicarboxylic acids ligands (5‐H₂HIP = 5‐hydroxyisophthalic acid; 2,6‐H₂NDC = 2,6‐naphthalenedicarboxylic acid) and 1,4‐bis(benzimidazol‐1‐yl)‐2‐butylene (L). Due to its good water stability as well as the strong luminescent emission around room temperature, complex 2 has the high selectivity and sensibility of fluorescence detection to the ceftriaxone sodium (a kind of antibiotic) with the detection limit up to ppm lever. The treatment activity of the compounds on age‐related macular degeneration was assessed and the specific mechanism was investigated. First of all, the inflammasome activation in the endothelial cells of retina was evaluated with western blot. In addition to this, the down‐stream production of the inflammasome activation was also measured with ELISA detection kit.     

不同年龄段天然牙的摩擦磨损行为研究

采用往复滑动摩擦磨损试验台考察了不同年龄段的天然牙同钛合金配副时的摩擦学性能.结果表明:天然牙的摩擦磨损行为同年龄密切相关,早期和中期恒牙的摩擦磨损行为相似,磨损表面主要呈现轻微擦伤迹象,中期恒牙的抗磨性能最佳;乳牙及晚期恒牙的摩擦系数变化波动较大,抗磨性能不佳,磨损表面主要呈现严重犁削和剥落特征.     

Optimizing Age Penalty in Time-Varying Networks with Markovian and Error-Prone Channel State

In this paper, we consider a scenario where the base station (BS) collects time-sensitive data from multiple sensors through time-varying and error-prone channels. We characterize the data freshness at the terminal end through a class of monotone increasing functions related to Age of information (AoI). Our goal is to design an optimal policy to minimize the average age penalty of all sensors in infinite horizon under bandwidth and power constraint. By formulating the scheduling problem into a constrained Markov decision process (CMDP), we reveal the threshold structure for the optimal policy and approximate the optimal decision by solving a truncated linear programming (LP). Finally, a bandwidth-truncated policy is proposed to satisfy both power and bandwidth constraint. Through theoretical analysis and numerical simulations, we prove the proposed policy is asymptotic optimal in the large sensor regime.     

Precise Radiometry: Some Recent Aspects of Fruitful Interaction with Atomic Physics

Modern radiometric analytics demands a complex consideration of nuclear and electron shell processes, if more pretentious aims are envisaged. As an example the small variation of decay rates of radionuclides presents possibilities for information on chemical situations of decaying atoms. In principle this phenomenon is well known since many years, but now the situation is such that, e.g. in ^99mTc internal conversion, a full agreement of the difficult experiments and the respective theory was established. The secondary emission of X-rays as a consequence of high excitation of electron shells in combination with nuclear transitions supplies another example for a methodical progress of radiometry. Investigations on ⁵¹Cr as an electron capture nuclide have shown that chemically induced variations of the K_α to K_β X-ray intensity ratio is at least qualitatively understood.     

Discussion of “Virtual age,is it real?”

In this note, some point of views on virtual ages are presented in terms of the discussion paper written by Finkelstein and Cha, which include generalized stochastic order‐based virtual ages, system‐level virtual ages, virtual ages in Weibull distribution and repair degrees with virtual ages. Finally, some possible future researches on virtual ages are described.     

Logging damage and injured tree mortality in tropical forest management

Using insights from the forest ecology literature, we analyze the effect of injured trees on stand composition and carbon stored in above‐ground biomass and the implications for forest management decisions. Results from a Faustmann model with data for a tropical forest on Kalimantan show that up to 50% of the basal area of the stand before harvest can consist of injured trees. Considering injured trees leads to an increase in the amount of carbon in above‐ground biomass of up to 165%. These effects are larger under reduced impact logging than under conventional logging. The effects on land expectation value and cutting cycle are relatively small. The results suggest that considering injured trees in models for tropical forest management is important for the correct assessment of the potential of financial programs to store carbon and conserve forest ecosystem services in managed tropical forests, such as reducing emissions from deforestation and forest degradation and payment for ecosystem services. Recommendations for Resource Managers

• Considering the role of injured trees is important for managing tropical forests
• These trees can cover up to 50% of basal area and contain more than 50% of the carbon stored in above‐ground biomass
• Reduced impact logging leads to a larger basal area of injured trees and more carbon stored in injured trees than conventional logging
• Injured trees play an important role when assessing the potential for carbon storage in the context of payment for forest ecosystem services.

     

A simple polymer electrolyte membrane system for enrichment of low-level tritium (3H) in environmental water samples

Tritium (³H) is an essential tracer of the Earth's water cycle; yet widespread adoption of tritium in hydrologic studies remains a challenge because of analytical barriers to quantification and detection of ³H by electrolytic pre-concentration. Here, we propose a simple tritium electrolytic enrichment system based on the use of solid polymer electrolyte membranes (PEMs) that can be used to enrich ³H in 250–3000?mL environmental water samples to a 10-mL final volume. The IAEA PEM-³H system reported here can produce high enrichment factors (>70-fold) and, importantly, removes some of the deterrents to conventional ³H enrichments methods, including the use of toxic electrolysis and neutralization chemicals, spike standards, a complex electrolysis apparatus that requires extensive cooling and temperature controls, and improves precision by eliminating the need for tracking recovery gravimetrics. Preliminary results with varying operating conditions show ³H enrichments to 70-fold and higher are feasible, spanning a wide range of tritium activities from 5 to 150 TU with a precision of ～4.5?%. Further work is needed to quantify inter-sample memory and to establish lower ³H detection limits. The IAEA PEM-³H system is open source, with 3-D CAD and design files made freely available for adoption and improvement by others.     

Naphthalene and benzene levels in microenvironments associated with potential exposure: new and old apartments with moth repellents,and cabins of passenger cars

A lesser degree of information is available with respect to microenvironments associated with potential exposure to naphthalene, in comparison with other volatile organic compounds. The current study investigated the levels of benzene as well as naphthalene, both in the indoor and outdoor air of apartments and in the cabins of passenger cars. Two groups of 20 apartment buildings (20 new and 20 old) were chosen on the basis of the selection criteria (apartment location and size). In addition, 10 actual commuters were recruited for this study. The equal number of drivers was recruited for the study for comparison of two types of fuels for vehicles (five drivers of gasoline-fuelled and five drivers of diesel-fuelled passenger cars). Indoor naphthalene concentrations were similar between old and new apartments, while the benzene concentrations in new apartments were significantly higher than those of old apartments. The naphthalene concentrations in bedrooms, where wardrobes with moth repellent (MRs) were placed, were significantly higher than those for living rooms where no MRs were present. In turn, these indoor concentrations were significantly higher than outdoor levels. It is noteworthy that the mean and median values of naphthalene measured in the bedrooms exceeded the USEPA RfC (inhalation reference concentration) of 3?µg?m^?3, and the living room values were close to the RfC, while the residential benzene levels exceeded the European benzene limit of 5?µg?m^?3. In contrast, the maximum outdoor levels were well below that of the RfC. The use of passenger cars appeared to be a significant daily activity for both naphthalene and benzene exposure. The naphthalene-to-benzene ratios varied with the type of microenvironments. Both the indoor naphthalene and benzene concentrations in the present study were much higher than those of other studies.