Evaluation of carbonic anhydrase and paraoxonase inhibition activities and molecular docking studies of highly water-soluble sulfonated phthalocyanines

The investigation of carbonic anhydrase and paraoxonase enzyme inhibition properties of water-soluble zinc and gallium phthalocyanine complexes ( 1 and 2 ) are reported for the first time. The binding of p-sulfonylphenoxy moieties to the phthalocyanine structure favors excellent solubilities in water, as well as providing an inhibition effect on carbonic anhydrase (CA) I and II isoenzymes and paraoxonase (PON1) enzyme. According to biological activity results, both complexes inhibited hCA I, hCA II, and PON1. Whereas 1 and 2 showed moderate hCA I and hCA II (off-target cytosolic isoforms) inhibitory activity (Ki values of 26.09 µM and 43.11 µM for hCA I and 30.95 µM and 33.19 µM for hCA II, respectively), they exhibited strong PON1 (associated with high-density lipoprotein [HDL]) inhibitory activity (Ki values of 0.37 µM and 0.27 µM, respectively). The inhibition kinetics were analyzed by Lineweaver–Burk double reciprocal plots. It revealed that 1 and 2 were noncompetitive inhibitors against PON1, hCA I, and hCA II. These complexes can be more advantageous than other synthetic CA and PON inhibitors due to their water solubility. Docking studies were carried out to examine the interactions between hCA I, hCA II, and PON1 inhibitors and metal complexes at a molecular level and to predict binding energies.     

First real-time measurement of the evolving 2H/1H ratio during water evaporation from plant leaves

We have studied the temporal behaviour of the deuterium isotope ratio of water vapour emerging from a freshly cut plant leaf placed in a dry nitrogen atmosphere. The leaf material was placed directly inside the sample gas cell of the stable isotope ratio infrared spectrometer. At the reduced pressure (～40 mbar) inside the cell, the appearance of water evaporating from the leaf is easily probed by the spectrometer, as well as the evolving isotope ratios, with a precision of about 1 ‰. The demonstration experiment we describe measures the ²H/¹H isotope ratio only, but the experiment can be easily extended to include the ¹⁸O/¹⁶O and ¹⁷O/¹⁶O isotope ratios. Plant leaf water isotope ratios provide important information towards quantification of the different components in the ecosystem water and carbon dioxide exchange.     

Measuring δ13C of atmospheric air with non-dispersive infrared spectroscopy

The potential use of non-dispersive infrared spectroscopy for measuring δ¹³C in air is demonstrated. This technique has already been successfully established for breath test analyses in medical diagnostics, where the CO₂ concentration ranges from 1 to 5 vol.% in the exhaled breath of vertebrates. For breath tests, the sensitivity and accuracy has been improved to reach a standard deviation of 0.2 ‰ (delta-value). Further adjustments were necessary to improve the sensitivity of the instrument at concentration levels typical of atmospheric air. The long-term stability is given by a standard deviation of 0.35 ‰ for CO₂ concentrations of about 400 ppm with signal averaging over 60 s.     

基于拉曼光谱的储层沥青热演化特征及其判别

为了明确储层沥青热演化程度与激光拉曼光谱的关系,利用拉曼光谱无损分析和流体包裹体方法,对黔西南白层地区储层沥青拉曼光谱进行了定量化描述,首先获取了储层沥青其伴生流体包裹体均一温度,然后获得了储层沥青拉曼光谱图,并对比标准沥青成熟度分布图,确定了储层沥青热演化程度及其特征.结果表明:黔西南白层地区存在晚三叠世(230 M...     

一类规划问题所给最优性必要条件的注记

本文指出了一类规划问题所给最优性必要条件中所存在的问题。对于一些带有附加项，（如（x^TDx)^1/2‖Sx‖p）的单目标规划问题一般都给出了一个类似集合Z^0 ，并以“Z^0为空集”作为一个前提条件。本文指出此条件太强，并论证了当只有Z^0为空集时，就可推出强最优性必要条件，而不必要求“x^0是最优解”。     

Advances in laser-based isotope ratio measurements: selected applications

Small molecules exhibit characteristic ro-vibrational transitions in the near- and mid-infrared spectral regions, which are strongly influenced by isotopic substitution. This gift of nature has made it possible to use laser spectroscopy for the accurate analysis of the isotopic composition of gaseous samples. Nowadays, laser spectroscopy is clearly recognized as a valid alternative to isotope ratio mass spectrometry. Laser-based instruments are leaving the research laboratory stage and are being used by a growing number of isotope researchers for significant advances in their own field of research. In this review article, we discuss the current status and new frontiers of research on high-sensitivity and high-precision laser spectroscopy for isotope ratio analyses. Although many of our comments will be generally applicable to laser isotope ratio analyses in molecules of environmental importance, this paper concerns itself primarily with water and carbon dioxide, two molecules that were studied extensively in our respective laboratories. A complete coverage of the field is practically not feasible in the space constraints of this issue, and in any case doomed to fail, considering the large body of work that has appeared ever since the review by Kerstel in 2004 (Handbook of Stable Isotope Analytical Techniques, Chapt. 34, pp. 759–787). PACS  07.57.-c; 42.55.Px; 42.62.Fi; 93.90.+y; 91.67.Rx; 92.60.H-; 91.40.Zz; 91.62.Xy     

Highly luminescent water-dispersed silicon quantum dots for fluorometric determination of oxytetracycline in milk samples

A fluorescent probe based on silicon quantum dots (SiQDs) was developed for the selective and sensitive detection of oxytetracycline (OTC) via the inner filter effect (IFE). The water-soluble fluorescent SiQD was synthesized based on the reaction of 3-Aminopropyltriethoxysilane (APTES) and sodium citrate as precursors by the one-pot hydrothermal process. The strong fluorescence emission of quantum dots (QDs) was obtained at 440 nm when excited at 350 nm and OTC had a broad absorption band between 200 and 400 nm. The excitation spectrum of SiQDs was completely overlapped with the absorption spectrum of OTC. The light at an excitation wavelength of QDs absorbed by OTC caused a decrease in fluorescence intensity with an increase in the concentration of OTC. Under optimal conditions, the linear concentration range was 0.92–9.2 µg mL1 with a detection limit (LOD; S/N = 3) of 0.19 µg mL ^-1 . The proposed method was applied to the determination of OTC in milk samples and satisfactory recoveries (98.8–100.5%) with low RSD % values (0.93–2.31%) were achieved. This simple, selective, sensitive, rapid, and cheap method can be used as a promising tool for OTC analysis in food safety.     

Bis benzothiophene Schiff bases: synthesis and in silico-guided biological activity studies

Since benzo [ b ] thiophene scaffold is one of the privileged structures in drug discovery as this core exhibitsactivities for different biological problems, in this study bis (benzo[ b ]thiophene-2-yl) alkyl methanimine derivatives (1-9) were synthesized by reacting benzo[ b ]thiophene-2-carbaldehyde with diamines. All newly compounds were characterized by IR, ¹H NMR and ¹³C NMR spectroscopic methods. Synthesized compounds were investigated using binary QSARbased models on therapeutic activity prediction of synthesized compounds and they showed high predicted activities in following diseases: bacterial, angina, allergy, depression and obesity. Thus, they were then tested for their antimicrobial and antileishmanial activities as a result of this theoretical study. Compound 1(N, N’- (propane-1,3-diyl) bis (1-(benzo [ b ] thiophene-2-yl)) methanimine) was found the most active compound in both diseases. Thus, its molecular docking studies were also carried out.     

Steady vortical flow around a finite plate

An explicit solution for a layer of fluid with constant vorticitysurrounding a thin plate of finite length is obtained usingelementary conformal mapping methods. In the limit of largeplate length the behaviour of the solution near the ends ofthe plate tends to that of the previously known solution fora semi-infinite plate. Contour dynamics is used to investigatethe stability of the steady solutions.