Switching ion binding selectivity of thiacalix[4]arene monocrowns at liquid–liquid and 2D-confined interfaces

Understanding the interaction of ions with organic receptors in confined space is of fundamental importance and could advance nanoelectronics and sensor design. In this work, metal ion complexation of conformationally varied thiacalix[4]monocrowns bearing lower-rim hydroxy (type I), dodecyloxy (type II), or methoxy (type III) fragments was evaluated. At the liquid–liquid interface, alkylated thiacalixcrowns-5(6) selectively extract alkali metal ions according to the induced-fit concept, whereas crown-4 receptors were ineffective due to distortion of the crown-ether cavity, as predicted by quantum-chemical calculations. In type-I ligands, alkali-metal ion extraction by the solvent-accessible crown-ether cavity was prevented, which resulted in competitive Ag+ extraction by sulfide bridges. Surprisingly, amphiphilic type-I/II conjugates moderately extracted other metal ions, which was attributed to calixarene aggregation in salt aqueous phase and supported by dynamic light scattering measurements. Cation–monolayer interactions at the air–water interface were monitored by surface pressure/potential measurements and UV/visible reflection–absorption spectroscopy. Topology-varied selectivity was evidenced, towards Sr2+ (crown-4), K+ (crown-5), and Ag+ (crown-6) in type-I receptors and Na+ (crown-4), Ca2+ (crown-5), and Cs+ (crown-6) in type-II receptors. Nuclear magnetic resonance and electronic absorption spectroscopy revealed exocyclic coordination in type-I ligands and cation–π interactions in type-II ligands

Determining the Amount of Phenylpropanoids in Belowground Organs of Purple Coneflower (Echinacea purpurea (L.) Moench., Asteraceae)

От эхинацеи пурпурной получают виды лекарственного растительного сырья: траву свежую и высушенную, корневища с корнями. В них содержится сумма фенилпропаноидов (ранее «оксикоричные кислоты», «гидроксикоричные кислоты») и их производные, обеспечивающие иммуностимулирующий эффект препаратов, основным из которых является настойка. Накопление суммы фенилпропаноидов в корневищах с корнями эхинацеи наименее изучено. Цель – изучение влияния сроков и кратности удаления надземной части на содержание суммы фенилпропаноидов в корневищах с корнями эхинацеи, полученных от растений разных возрастов при культивировании, а также определение содержания изучаемых веществ в настойке при разной степени измельчения сырья. Исследованы корневища с корнями эхинацеи пурпурной, заготовленные в Москве в 2008–2010 гг. в фазу окончания вегетации растений 2-го, 3-го, 4-го, 5-го, 7-го гг. развития. Побеги скашивали в фазы стеблевания (однократно и многократно в течение вегетации), бутонизации, цветения. Контроль – получение сырья без удаления надземной части. В 2008–2009 гг. наибольшее накопление суммы фенилпропаноидов в подземных органах наблюдали при многократном и однократном скашивании побегов в период стеблевания, независимо от возраста растений. Удаление побегов в фазах бутонизации и цветения привело к значительному снижению содержания суммы фенилпропаноидов. В июле-августе 2010 г. в регионе была засуха. Наименьшее содержание изучаемых веществ в сырье отмечено при многократном удалении побегов. В лучшем положении оказалось сырье растений, у которых надземную массу срезали однократно в фазу стеблевания. При сравнении растений разных возрастов установлено, что в сырье растений 2–4 гг. вегетации накопление веществ, независимо от срока удаления надземной части и года проведения опыта, достоверно выше, чем в сырье от растений старших возрастов. Рекомендовано дополнить «Агрорекомендацию по возделыванию эхинацеи пурпурной» при выращивании для получения корневищ с корнями агроприемом многократного скашивания надземной части в фенологической фазе стеблевания. Влияние размера частиц измельченного сырья (от 0,25 мм до 1,0 мм) на содержание биологически активных веществ в настойке не наблюдалосьEchinacea purpurea (L.) Moench plants serve as a source of medicinal raw materials: fresh and dried aboveground parts and rhizomes with roots (Rhizomata cum radicibus). They contain total phenylpropanoids (formerly “oxycinnamic acids”, “hydroxycinnamic acids”) and their derivatives, which underlie the immunostimulatory effect of the preparations. Tincture is the most common preparation. Accumulation of total phenylpropanoid derivatives in Echinacea rhizomes with roots is the least studied aspect. The purpose of the present work is to study the effect of the timing and frequency of removal of the aboveground part on total phenylpropanoids in Echinacea rhizomes with roots collected from cultivated plants of different ages. Another aim was to determine total phenylpropanoids in the tincture prepared from raw material ground to various degrees. Echinacea purpurea rhizomes with roots harvested in Moscow in 2008–2010, at the end of the growing period of plants aged 2, 3, 4, 5, and 7 years, were studied. The shoots were cut down during the stem formation (by single and repeated mowing during the growing period), budding, and flowering stages. The intact raw material was used to provide control samples. In 2008–2009, the highest accumulation of phenylpropanoid derivatives in rhizomes with roots was observed in groups with both repeated and single shoot removals performed during the shoot development stage at all plant ages. The shoot removals during the budding and flowering stages resulted in a significant reduction in phenylpropanoids. During the regional drought in July and August 2010, the raw material samples in the group with repeated shoot removals demonstrated the lowest accumulation of phenylpropanoids. The samples in the group with single shoot removal during the shoot development stage showed greater phenylpropanoid accumulation compared with the repeated mowing group. The content of phenylpropanoids in raw material from 2–4-year-old plants, regardless of the period of shoot removal and the year of the experiment, was significantly higher than in the raw material from older plants. It is recommended to supplement the “Agro-recommendation for the cultivation of Echinacea purpurea” with the agricultural method of repeated mowing of the aboveground part in the phenological phase of shoot development when the plant is grown as a source of rhizomes with roots. No effect of the particle size of the ground raw material (from 0.25 to 1.0 mm) on total phenylpropanoids in the tincture has been reveale

Semantic and Stylistic Features of Kant’s Observations on the Feeling of the Beautiful and the Sublime: The Art of Seeing and Describing an Object

Immanuel Kant’s Observations on the Feeling of the Beautiful and the Sublime is examined in the context of the emergence of the epistemological practice of scientific observation. By focusing on the genre-stylistic and semantic-structural features of the text the authors demonstrate the mechanisms of observation as well as the methods of describing the results characteristic of mid-eighteenth century science. The authors consider Kant’s treatise to be a hybrid text: on the one hand, it attests to the importance of the natural science paradigm and the degree of its influence on the humanities in the modern period; and, on the other hand, it bears witness to the multi-genre character of philosophical treatises, combining as they do the considered and serious wisdom of philosophy, the precision of scientific terminology and the figurativeness of a work of fiction. Kant is perceived not only as a researcher and philosopher capable of bringing out the essence of the particular and changeable captured in observation, but as a writer with a consummate command of the apparatus for keeping the reader’s attention through linguistic devices and practices of image-creating. The authors demonstrate how the categories of the “beautiful” and “sublime” become a general framework for the description of the moral and mental properties of human nature. The authors show that Kant’s use of “aesthetic” wording in the title of his treatise does not announce that his aim is analysis of artistic perception and practices, but mainly refers to the form of his anthropological study and conceptualisation of scientific knowledge. Kant has transferred the technique of visualisation from natural sciences to the objects of philosophical inquiry, thus contributing to the development in the humanities of representative practices, the scientific method of observation as well as the corresponding epistemic and literary genre

Public authorities as an object of modern historical and legal research

The purpose of the study is to analyze the views of theoretical scientists on the concept of public authorities and the place of local self-government bodies in the system of public authorities, based on well-established concepts, doctrines, and ideas developed in modern realities. To achieve the stated goals and objectives in scientific work, general scientific and specific scientific methods were used. The principles of objectivity and consistency, methods of analysis, synthesis, comparison made it possible to study the views of theoretical scientists, highlighting the argumentation that is significant for the research topic, based on facts, guided by the principles of reliability and impartiality, considering the topic in all its versatility and contradictoriness. The research is based on the theoretical works of Russian scientists studying various aspects of the multifaceted problem of public authorities as state institutions. The novelty of the research lies in the attempt to theoretically comprehend and scientifically analyze the concepts of public authority and public authorities based on the works of domestic authors, as well as to determine the positions of theoretical scientists in the place of local self-government bodies in the system of public authorities. The study made it possible to substantiate the rejection of the established stereotypes in the identification of the concepts of “public power” and “state power”, the reorientation of legal science towards the formation of the concept of state power as a variant of public power, the legal basis of which is the law. The paper also concludes the implementation of power relations through public authorities. At the same time, a lack of a unified approach to determining the place of local self-government bodies in the system of public authorities at present is indicated

Physiological and biochemical characteristics of Populus tremula leaves in anthropogenic disturbed habitats

The main morphological, anatomical, physiological and biochemical characteristics of Populus tremula undergrowth leaves as resistance indicators under conditions of coal pit waste dump are considered. There has been established high variability of morphological parameters and chemical elements composition and anatomical structure peculiarities. There are reported the differences in the content of photosynthetic pigments and phenol compounds

Thermally Stable Nitrothiacalixarene Chromophores: Conformational Study and Aggregation Behavior

Achieving high thermal stability and control of supramolecular organization of functional dyes in sensors and nonlinear optics remains a demanding task. This study was aimed at the evaluation of thermal behavior and Langmuir monolayer characteristics of topologically varied nitrothiacalixarene multichromophores and phenol monomers. A nitration/azo coupling alkylation synthetic route towards partially O-substituted nitrothiacalixarenes and 4-nitrophenylazo-thiacalixarenes was proposed and realized. Nuclear magnetic resonance (NMR) spectroscopy and X-ray diffractometry of disubstituted nitrothiacalix[4]arene revealed a rare 1,2-alternate conformation. A synchronous thermal analysis indicated higher decomposition temperatures of nitrothiacalixarene macrocycles as compared with monomers. Through surface pressure/potential-molecular area measurements, nitrothiacalixarenes were shown to form Langmuir monolayers at the air–water interface and, through atomic force microscopy (AFM) technique, Langmuir–Blodgett (LB) films on solid substrates. Reflection-absorption spectroscopy of monolayers and electronic absorption spectroscopy of LB films of nitrothiacalixarenes recorded a red-shifted band (290 nm) with a transition from chloroform, indicative of solvatochromism. Additionally, shoulder band at 360 nm was attributed to aggregation and supported by gas-phase density functional theory (DFT) calculations and dynamic light scattering (DLS) analysis in chloroform–methanol solvent in the case of monoalkylated calixarene 3. Excellent thermal stability and monolayer formation of nitrothiacalixarenes suggest their potential as functional dyes

<i>N</i>-(((1<i>S</i>,5<i>R</i>)-6,6-Dimethylbicyclo[3.1.1]hept-2-en-2-yl)methyl)-3-dodecan/tetradecanamido-<i>N</i>,<i>N</i>-dimethylpropan-1-aminium Bromide

The syntheses of the title compounds were performed using lauric and myristic acids. The compounds obtained were characterized using 1H-, 13C-NMR and 2D 1H-1H COSY, 1H-13C HSQC NMR, IR, and high-resolution mass spectrometry. Both compounds exhibited bactericidal activity on S. aureus comparable to that of a reference drug (miramistin). Compound 10, with lauric acid fragment, had a 16-fold higher activity on P. aeruginosa compared to compound 11, which in turn contains myristic acid fragment (with minimum inhibitory concentrations of 32 and 512 μg/mL, respectively). Compound 11 exhibited a pronounced activity against all types of fungi (higher than the activity of miramistin), while the activity of compound 10 was considerably lower. Thus, compound 11 can serve as a promising antimicrobial agent for the treatment of various fungal and staphylococcal infections, while compound 10 is of interest to treat P. aeruginosa-associated infections

Synthesis of D-π-A′-π-A Chromophores with Quinoxaline Core as Auxiliary Acceptor and Effect of Various Silicon-Substituted Donor Moieties on Thermal and Nonlinear Optical Properties at Molecular and Material Level

Novel D-π-A′-π-A chromophores with quinoxaline cores as auxiliary acceptors and various donor moieties (aniline, carbazole, phenothiazine, tetrahydroquinoline) containing bulky tert-butyldimethylsilyloxy (TBDMSO) groups and tricyanofuranyl (TCF) acceptors with bulky cyclohexylphenyl substituents were synthesized via eight- to nine-step procedures, and their photo-physical and thermal properties were investigated. The values of the chromophores’ first hyperpolarizabilities were calculated in the framework of DFT at the M06-2X/aug-cc-pVDZ computational level; the effect of the introduction of the TBDMSO group into the donor fragment is shown to be inessential, as this group is not coupled to the π-conjugated system of the chromophore. The chromophore with the tetrahydroquinoline donor has a first hyperpolarizability value of 937 × 10−30 esu, which is the highest for the studied chromophores. Atomistic modeling of composite materials with the studied chromophores as guests demonstrated that the presence of bulky substituent in the donor fragment prevents notable aggregation of chromophores, even at high chromophore content (40 wt.%). The nonlinear optical performance of guest–host materials with 25 and 40 wt.% of suggested chromophore content was studied using a second harmonic generation technique to give the NLO coefficient, d33 up to 52 pm/V

Calix[4]Resorcinarene Carboxybetaines and Carboxybetaine Esters: Synthesis, Investigation of In Vitro Toxicity, Anti-Platelet Effects, Anticoagulant Activity, and BSA Binding Affinities

As a result of bright complexation properties, easy functionalization and the ability to self-organize in an aqueous solution, amphiphilic supramolecular macrocycles are being actively studied for their application in nanomedicine (drug delivery systems, therapeutic and theranostic agents, and others). In this regard, it is important to study their potential toxic effects. Here, the synthesis of amphiphilic calix[4]resorcinarene carboxybetaines and their esters and the study of a number of their microbiological properties are presented: cytotoxic effect on normal and tumor cells and effect on cellular and non-cellular components of blood (hemotoxicity, anti-platelet effect, and anticoagulant activity). Additionally, the interaction of macrocycles with bovine serum albumin as a model plasma protein is estimated by various methods (fluorescence spectroscopy, synchronous fluorescence spectroscopy, circular dichroic spectroscopy, and dynamic light scattering). The results demonstrate the low toxicity of the macrocycles, their anti-platelet effects at the level of acetylsalicylic acid, and weak anticoagulant activity. The study of BSA–macrocycle interactions demonstrates the dependence on macrocycle hydrophilic/hydrophobic group structure; in the case of carboxybetaines, the formation of complexes prevents self-aggregation of BSA molecules in solution. The present study demonstrates new data on potential drug delivery nanosystems based on amphiphilic calix[4]resorcinarenes for their cytotoxicity and effects on blood components