Alkaloids in environmental tobacco smoke-filled rooms

Considering the importance of alkaloids in tobacco smoke, their presence was evaluated in real work environments. Sampling was carried out with fixed pumps and eventual degradation of the alkaloids during collection and storage until analysis was tested. A quantification method with an alternative internal standard (quinaldine) was evaluated and proposed. Offices and leisure rooms with high smoking intensity were chosen in order to detect minor alkaloids. The correlation between the environmental tobacco smoke markers - nicotine, 3-ethenylpyridine and myosmine - and the minor compounds was evaluated and all R² were higher than 0.538. Nicotine levels quantified in the office rooms ranged from 0.02 to 64.67pg/m³ and a maximum of 129.33pg/m³ was found in one leisure room with very high smoking intensity. Myosnline and nicotyrine were the most abundant minor alkaloids and very high contents were. quantified in the leisure room mentioned previously.     

A multi-period stochastic portfolio optimization model applied for an airline company in the EU ETS

This paper aims to set up and solve a multi-period stochastic portfolio optimization model from an airline company’s point of view, considering all the specific European Union Emissions Trading Scheme (EU ETS) regulatory, managerial and trading constraints (i.e. physical constraints). Our contribution to existing academic literature is multiple. As the first ever case, we apply this technique to the aviation sector, a newly included sector within the EU ETS. More than mainly incorporating physical and technical (‘engineering’) features and focusing on short-term planning issues, we particularly address financial features and focus on mid-term planning issues. Therefore, instead of using spot prices, we run Monte Carlo simulations of correlated geometric Brownian motions (GBM) for traded futures prices of various emission allowance types for different CO₂ delivery time periods. We thereby specifically refer to the existing exchange-traded emission allowance types EU Emission Allowance (EUA) and Certified Emission Reduction (CER). By implementing actually valid and real-world-oriented regulatory constraints for EU ETS, namely managerial and trading constraints, our model implies a real-life application. We also highlight the possibility of banking and borrowing of emission allowances between CO₂ compliance periods, which is a crucial regulatory feature of EU ETS.     

香烟燃烧产生的亚微米颗粒物动态粒径谱特征

应用SMPS (Scanning Mobility Particle Sizer)对ETS (Environmental Tobacco Smoke)亚微米颗粒物的粒径谱演变进行了测量分析.结果发现,ETS颗粒物在10~500nm范围内呈对数正态单峰分布,数量粒径谱和质量粒径谱的演化有类似的递减趋势,但其浓度衰减率有明显的不同.分析得知,由于在演化过程中颗粒物直径是动态变化的,并不能用简单的方法获得凝并和沉积损失率.     

On the Modeling of CO2 EUA and CER Prices of EU‐ETS for the 2008–2012 Period

Increased consumption of fossil fuels in industrial production has led to a significant elevation in the emission of greenhouse gases and to global warming. The most effective international action against global warming is the Kyoto Protocol, which aims to reduce carbon emissions to desired levels in a certain time span. Carbon trading is one of the mechanisms used to achieve the desired reductions. One of the most important implications of carbon trading for industrial systems is the risk of uncertainty about the prices of carbon allowance permits traded in the carbon markets. In this paper, we consider stochastic and time series modeling of carbon market prices and provide estimates of the model parameters involved, based on the European Union emissions trading scheme carbon allowances data obtained for 2008–2012 period. In particular, we consider fractional Brownian motion and autoregressive moving average–generalized autoregressive conditional heteroskedastic modeling of the European Union emissions trading scheme data and provide comparisons with benchmark models. Our analysis reveals evidence for structural changes in the underlying models in the span of the years 2008–2012. Data‐driven methods for identifying possible change‐points in the underlying models are employed, and a detailed analysis is provided. Our analysis indicated change‐points in the European Union Allowance (EUA) prices in the first half of 2009 and in the second half of 2011, whereas in the Certified Emissions Reduction (CER) prices three change‐points have appeared, in the first half of 2009, the middle of 2011, and in the second half of 2012. These change‐points seem to parallel the global economic indicators as well. Copyright © 2016 John Wiley & Sons, Ltd.     

Nature of the water/aromatic parallel alignment interactions

The water/aromatic parallel alignment interactions are interactions where the water molecule or one of its O? H bonds is parallel to the aromatic ring plane. The calculated energies of the interactions are significant, up to ΔE_{CCSD(T)(limit)} = ?2.45 kcal mol^?1 at large horizontal displacement, out of benzene ring and CH bond region. These interactions are stronger than CH···O water/benzene interactions, but weaker than OH···π interactions. To investigate the nature of water/aromatic parallel alignment interactions, energy decomposition methods, symmetry‐adapted perturbation theory, and extended transition state‐natural orbitals for chemical valence (NOCV), were used. The calculations have shown that, for the complexes at large horizontal displacements, major contribution to interaction energy comes from electrostatic interactions between monomers, and for the complexes at small horizontal displacements, dispersion interactions are dominant binding force. The NOCV‐based analysis has shown that in structures with strong interaction energies charge transfer of the type π → σ*(O? H) between the monomers also exists. © 2014 Wiley Periodicals, Inc.     

Liquid chromatography/tandem mass spectrometric method for the simultaneous determination of tobacco-specific nitrosamine NNK and its five metabolites

A sensitive and robust high-performance liquid chromatography-electrospray ionization tandem mass spectrometry method to analyze 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its five metabolites in one passage was developed and validated. The method achieved excellent reproducibility and accuracy. Linearity was observed for all six compounds (R² = 0.999) with detection limits (S/N ≥ 3) ranging from 0.2 to 2.4 pg on column and 0.01-0.12 ng ml⁻¹ in samples injected. Average intra-day and inter-day variations (% R.S.D.) were 1.2 and 3.5%, respectively. A sample preparation method involving C8 and C18 solid phase extraction provided satisfactory recovery of the analytes in mouse urine. Each NNK metabolite was identified by its chromatographic retention time and specific fragmentation pattern. Since the carcinogenicity of NNK is related to its metabolism, the method described in this report should facilitate toxicological investigations into the carcinogenesis due to NNK exposure in the environment.     

Theoretical description of dihydrogen/hydride and trihydride molybdocene complexes: An insight from static and molecular dynamics simulations

In this study ab initio Car–Parrinello molecular dynamics simulations, extended transition state (ETS)‐natural orbitals for chemical valence (NOCV) and QTAIM bonding analyses, were performed to characterize the ansa‐bridged molybdocene complexes [(C₅H₄)₂XMe₂MoH₃]⁺ for X = C, Si, Ge, Sn, Pb, and nonbridged Cp₂MoH system. The results have shown that the [(C₅H₄)₂CMe₂MoH(H₂)]⁺ complex exhibits nonclassical dihydrogen/hydride (H₂/H) conformation (97.6% of time of simulation), contrary to trihydride (H₃) structure noted for nonbridged Cp₂MoH (86.9%) and ansa‐bridged [(C₅H₄)₂SnMe₂MoH₃]⁺ (84.8%), [(C₅H₄)₂PbMe₂MoH₃]⁺ (84.9%) systems. Further, [(C₅H₄)₂SiMe₂MoH₃]⁺ and [(C₅H₄)₂GeMe₂MoH₃]⁺ complexes, appeared to exist in both conformations (H₂/H—55.4%, H₃—44.6% for Si‐based system and H₂/H—36.2%, H₃—63.8 % for germanium congener). It has been proven that the “steric availability” of the metal center, measured by the changes in the Cp? Mo? Cp angle (α), determines the existence of a given conformation—namely, the smaller value of the angle (molybdenum is sterically more accessible) the larger preference for the formation of dihydrogen/hydride structure. ETS‐NOCV method allowed to conclude that increase in the Cp? Mo? Cp angle (from α ca. 120° to α ca. 150°) leads to the enhancement of donation from H₂ and back‐donation from Mo to the σ*(H? H), what consequently leads to breaking of the H? H bond and formation of the trihydride structure. Systematical increase in the charge depletion from the σ‐bonding orbital of H₂ can be related to the reduction of the energy gap between the major orbitals involved in this contribution, namely highest occupied molecular orbital (HOMO) of H₂ with lowest unoccupied molecular orbital (LUMO) of [MoHL]⁺; ΔE = 0.0868 a.u. [for L =(C₅H₄)₂C], ΔE = 0.0827a.u. [for L = (C₅H₄)₂Si] ΔE = 0.0638 a.u. [for L = Cp₂]. Further, the relatively low energetic barrier to hydrogen exchange (ΔE^# = 3.3 kcal/mol) for carbon‐bridged complex, [(C₅H₄)₂CMe₂MoH_c(H_aH_b)]⁺ → [(C₅H₄)₂ CMe₂MoH_a(H_bH_c)]⁺, is related to strengthening of the Mo–H bonds when going from the substrate to the transition state (TS). Notably higher barrier to hydrogen rotation (ΔE^# = 10.1 kcal/mol) in [(C₅H₄)₂CMe₂MoH(H₂)]⁺ is due to lowering in the electrostatic stabilization as well as weakening of the donation (H₂ → Mo charge transfer) and practically lack‐of back‐donation (Mo → H₂) in the rotated TS. © 2012 Wiley Periodicals, Inc.