Exhaled breath condensate: Determination of non-volatile compounds and their potential for clinical diagnosis and monitoring. A review

Exhaled breath condensate is a promising, non-invasive, diagnostic sample obtained by condensation of exhaled breath. Starting from a historical perspective of early attempts of breath testing towards the contemporary state-of-the-art breath analysis, this review article focuses mainly on the progress in determination of non-volatile compounds in exhaled breath condensate. The mechanisms by which the aerosols/droplets of non-volatile compounds are formed in the airways are discussed with methodological consequences for sampling. Dilution of respiratory droplets is a major problem for correct clinical interpretation of the measured data and there is an urgent need for standardization of EBC. This applies also for collection instrumentation and therefore various commercial and in-house built devices are described and compared with regard to their design, function and collection parameters. The analytical techniques and methods for determination of non-volatile compounds as potential markers of oxidative stress and lung inflammation are scrutinized with an emphasis on method suitability, sensitivity and appropriateness. The relevance of clinical findings for each group of possible non-volatile markers of selected pulmonary diseases and methodological recommendations with emphasis on interdisciplinary collaboration that is essential for future development into a fully validated clinical diagnostic tool are given.     

Spherically Averaged Endpoint Strichartz Estimates For The Two­Dimensional Schrödinger Equation

The endpoint Strichartz estimates for the Schrödinger equation is known to be false in two dimensions[7]. However, if one averages the solution in L2 in the angular variable, we show that the homogeneous endpoint and the retarded half­endoint estimates hold, but the full retarded endpoint fails. In particular, the original verisions of these estimates hold for radial data     

A new method for the determination of the 34S/32S ratio of water-soluble sulphur in soil

A new method for the determination of the ³⁴S/³²S ratio of water-extractable sulphate in soil is described. Soils are extracted directly with deionized water, which is evaporated down. The remaining residue is then rehydrated and transferred to tin cups containing an adsorbent and mixed with an oxygen donor (V₂O₅). Samples are then analysed using a continuous flow isotope ratio mass spectrometer. The new method requires around 10?g soil per determination, compared to much larger amounts (up to kilograms) of soil required for the previous methods. Sample preparation and subsequent analysis is quick and efficient. The method is demonstrated using a number of soils collected from around the world to provide a range of determined δ³⁴S values. The δ³⁴S values of water-extractable sulphur were broadly similar to those of the soil total sulphur.     

High‐performance liquid chromatographic enantioseparation of (RS)‐bupropion using isothiocyanate‐based chiral derivatizing reagents

A high‐performance liquid chromatographic (HPLC) method for enantioseparation of bupropion was developed using two isothiocyanate‐based chiral derivatizing reagents, (S)‐1‐(1‐naphthyl) ethyl isothiocyanate, (S)‐NEIT, and (R)‐α‐methyl benzyl isothiocyanate, (R)‐MBIT. The diastereomers synthesized with (S)‐NEIT were enantioseparated by reversed‐phase HPLC using gradient elution with mobile phase containing water and acetonitrile, whereas diastereomers synthesized with (R)‐MBIT were enantioseparated using triethyl amine phosphate buffer and methanol. Derivatization conditions were optimized and the method was validated for accuracy, precision and limit of detection. The limit of detection was found to be 0.040–0.043 µg/mL for each of the diastereomers prepared with (S)‐NEIT. Copyright © 2013 John Wiley & Sons, Ltd.     

Theoretical Studies on the Mechanistic Insertions of Singlet Methylene and Halomethylene into Polar S‒H Bonds of Methanethiol,Ethanethiol, 1-Propanethiol and 2-Propanethiol

Abstract

The insertion of ¹CH₂, ¹CHF, ¹CF₂,¹CHCl, and ¹CCl₂ into primary and secondary polar S?H bonds of methanethiol, ethanethiol, 1-propanethiol, and 2-propanethiol have been investigated at HF (Hartree–Fock), MP2 (Møller–Plesset Perturbation Theory), and DFT (density functional theory) levels using 6-31G (d, p) basis set. The insertions follow a two-step mechanism. The potential energy surface exploration identifies ylide-like structures undergoing the 1,2-sigmatropic hydrogen shift concertedly giving the thioether product. But ¹CF₂ forms weak complexes involving 1,2-hydrogen shift. The barrier height in the concerted mechanism varies with the type of carbene moiety and S?H bond. The initial interaction seems to be a function of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies of thiols and carbenes, respectively. The natural bond orbital charge analysis showing a net charge flow from the substrate thiol to the reagent carbene at the transition states corroborates this fact.     

硫化铟锌的改性合成及光催化特性

随着社会经济的高速发展,能源的短缺和生态的破坏引起了人们的关注。近年来,寻找合适的解决方案已成为关注的重点。作为一种绿色环保技术,光催化由于其高效、低成本等优点而成为能源和环境问题的研究热点。在许多光催化材料中,三元硫化物硫化铟锌(ZnIn₂S₄)由于具有可见光响应特性、简单的制备方法和出色的稳定性而表现出巨大的潜力。然而,较高的载流子复合率限制了其光催化性能。近年来,许多研究报道了改性ZnIn₂S₄以提高其光催化性能,在此,本文详细介绍了各种改性研究,包括ZnIn₂S₄单体的合成、半导体化合物的结构、贵金属沉积、碳元素改性、离子掺杂。然后,系统完整地总结了ZnIn₂S₄在光催化、降解有机污染物、去除六价铬、还原CO₂和有机合成等方面表现出的光催化特性和机理。最后,对ZnIn₂S₄的发展前景提出了展望,以期ZnIn₂S₄光催化剂得到更广泛和深入的研究,尽快在实际生产中得到应用。     

Light-Driven Syngas Production over Defective ZnIn2S4 Nanosheets

Photocatalytic syngas (CO and H₂) production with CO₂ as gas source not only ameliorates greenhouse effect, but also produces valuable chemical feedstocks. However, traditional photocatalytic systems require noble metal or suffers from low yield. Here, we demonstrate that S vacancies ZnIn₂S₄ (V_S-ZnIn₂S₄) nanosheets are an ideal photocatalyst to drive CO₂ reduction into syngas. It is found that building S vacancies can endow ZnIn₂S₄ with stronger photoabsorption, efficient electron–hole separation, and larger CO₂ adsorption, finally promoting both hydrogen evolution reaction (HER) and CO₂ reduction reaction (CO₂RR). The syngas yield of CO and H₂ is therefore significantly increased. In contrast to pristine ZnIn₂S₄, the syngas yield over V_S-ZnIn₂S₄ can be improved by roughly ≈4.73 times and the CO/H₂ ratio is modified from 1:4.18 to 1:1. Total amount of syngas after 12 h photocatalysis is as high as 63.20 mmol g⁻¹ without use of any noble metals, which is even higher than those of traditional noble metal-based catalysts in the reported literatures. This work demonstrates the critical role of S vacancies in mediating catalytic activity and selectivity, and highlights the attractive ability of defective ZnIn₂S₄ for light-driven syngas production.     

Isotope Zusammensetzung Der Mineralwässer Der Mongolei

Abstract

The isotopic composition (D, ¹⁸O, ⁸⁷Sr, ³He) of thermal and mineral waters of Mongolia is discussed. The Sr-isotope ratio depends on the rock's contact. Near the Chubsugul-lake ³He-/⁴He-values are high. A certain similarity between the waters of Mongolia and those of East Siberia can be derived from the obtained data.