Điểm rotterdam là gì? Các công bố khoa học về Điểm rotterdam

Particle size-selective sampling refers to the collection of particles of varying sizes that potentially reach and adversely affect specific regions of the respiratory tract. Thoracic and respirable fractions are defined as the fraction of inhaled particles capable of passing beyond the larynx and ciliated airways, respectively, during inhalation. In an attempt to afford greater protection to exposed individuals, current size-selective sampling criteria overestimate the population means of particle penetration into regions of the lower respiratory tract. The purpose of our analyses was to provide estimates of the thoracic and respirable fractions for adults and children during typical activities with both nasal and oral inhalation, that may be used in the design of experimental studies and interpretation of health effects evidence. We estimated the fraction of inhaled particles (0.5-20 μm aerodynamic diameter) penetrating beyond the larynx (based on experimental data) and ciliated airways (based on a mathematical model) for an adult male, adult female, and a 10 yr old child during typical daily activities and breathing patterns. Our estimates show less penetration of coarse particulate matter into the thoracic and gas exchange regions of the respiratory tract than current size-selective criteria. Of the parameters we evaluated, particle penetration into the lower respiratory tract was most dependent on route of breathing. For typical activity levels and breathing habits, we estimated a 50% cut-size for the thoracic fraction at an aerodynamic diameter of around 3 μm in adults and 5 μm in children, whereas current ambient and occupational criteria suggest a 50% cut-size of 10 μm. By design, current size-selective sample criteria overestimate the mass of particles generally expected to penetrate into the lower respiratory tract to provide protection for individuals who may breathe orally. We provide estimates of thoracic and respirable fractions for a variety of breathing habits and activities that may benefit the design of experimental studies and interpretation of particle size-specific health effects.

Viene studiato a Catania, 40 m s.l.d.m., mediante contatori di G.M., lo spettro di energia degli elettroni negli sciami estesi dei raggi cosmici a due distanzed dal sistema che rivela gli sciami (d=0 ed=50 m) prendendo in considerazione successivamente sciami aventi nella parte centrale densità media Δ=72; 42; 25; 12,5; 6,25; 3,14 particelle/m2. I risultati sperimentali mostrano che lo spettro di energia degli elettroni negli sciami può essere espresso dalla relazioneN=K(E+E c)−ε, doveN è il numero di elettroni con energia maggiore diE, E c è l'energia critica in aria, ed ε è un esponente che dipende dalla densità media dello sciame e dalla distanza degli elettroni dall'asse dello sciame. I valori sperimentali di ε risultano inferiori ai valori che si ricavano dalla teoria a cascata elettrofotonica, cioè lo spettro sperimentale è più duro di quello previsto dalla teoria. Inoltre alla distanzad=50 m si trovano elettroni con energia troppo elevata per appartenere ad una cascata elettronica iniziata nell'alta atmosfera da un singolo elettrone. Per interpretare i risultati sperimentali viene abbandonata l'ipotesi della cascata puramente elettronica e viene ammesso che negli sciami estesi gli elettroni siano prodotti anche da parte di una componente meno assorbita degli elettroni in aria, la quale alimenta lo sciame e contribuisce allo sviluppo di esso.

In addition to maximizing economic benefits, reverse supply chains should further seek to maximize social benefits by increasing the quantity of waste electrical and electronic equipment (WEEE). The paper investigates cooperative models with different parties in a three-echelon reverse supply chain for WEEE consisting of a single collector, a single remanufacturer, and two retailers based on complete information. In addition, the optimal decisions of four cooperative models and the effect of the market demand of remanufactured WEEE products and the market share of two retailers on the optimal decisions are discussed. The results indicate that optimal total channel profit and recycle quantity in a reverse supply chain are maximized in a centralized model. The optimal total channel profit and recycle quantity increase with an increase in the market demand of remanufactured WEEE products. The three-echelon reverse supply chain consisting of duopolistic retailers maximizes total channel profit and recycle quantity in a reverse supply chain for WEEE.

The aim of this work was to study the anticoagulant activity of sulfonated xylan. The crude corncob xylans were isolated from corncob by alkaline extraction. The water-insoluble xylans were sulfonated using chlorosulfonic acid and dimethylformamide (DMF) to generate the water-soluble sulfonated xylan (WISX-S). The best conditions for the esterification were 1:1 of chlorosulfonic acid to DMF, keep time of 6 h and temperature of 70 °C by the orthogonal analysis. Degree of substitution of esterification product was 1.54. Anticoagulant properties of WISX-S1 and WISX-S2 were compared with normal saline and positive control heparin sodium. In vitro tests demonstrated that WISX-S2 can significantly prolong APTT and TT, but not PT. The results suggest that WISX-S2 may play the key role of anticoagulation through the intrinsic pathway and common pathway. The anticoagulant activity of xylan sulfates may be associated with the degree of substitution and molecular weight within a certain range.