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The lattice geometry of natural materials and the structural geometry of artificial materials are crucial factors determining their physical properties. Most materials have predetermined geometries that lead to fixed physical characteristics. Here, the demonstration of a carbon nanotube network serves as an example of a system with controllable orientation achieving on‐demand optical properties. Such a network allows programming their optical response depending on the orientation of the constituent carbon nanotubes and leads to the switching of its dielectric tensor from isotropic to anisotropic. Furthermore, it also allows for the achievement of wavelength‐dispersion for their principal optical axes – a recently discovered phenomenon in van der Waals triclinic crystals. The results originate from two unique carbon nanotubes features: uniaxial anisotropy from the well‐defined cylindrical geometry and the intersection interaction among individual carbon nanotubes. The findings demonstrate that shaping the relative orientations of carbon nanotubes or other quasi‐one‐dimensional materials of cylindrical symmetry within a network paves the way to a universal method for the creation of systems with desired optical properties. [ABSTRACT FROM AUTHOR]

Chirality is one of the most mysterious symmetry transformations. Very readily broken in biological systems, it is practically absent in naturally occurring inorganic materials and is very challenging to create artificially. Chiral optical wavefronts are often used for the identification, control, and discrimination of left‐ and right‐handed biological and other molecules. Thus, it is crucially important to create materials capable of chiral interaction with light, which would allow one to assign arbitrary chiral properties to a light field. This study utilizes van der Waals technology to assemble helical homostructures with chiral properties (e.g., circular dichroism). Because of the large range of van der Waals materials available, such helical homostructures can be assigned with very flexible optical properties. The approach is demonstrated by creating helical homostructures based on multilayer As2S3${\rm As}_2{\rm S}_3$ (arsenic trisulfide), which offers the most pronounced chiral properties even in thin structures due to its strong biaxial optically anisotropy. The work showcases that the chirality of an electromagnetic system may emerge at an intermediate level between the molecular and the mesoscopic one due to the tailored arrangement of non‐chiral layers of van der Waals crystals and without additional patterning. [ABSTRACT FROM AUTHOR]

A novel synthetic approach to 2,3,6‐trisubstituted pyridines, their 4,5‐dideuterated derivatives, 4,5‐13C2‐ and doubly‐labeled D2‐13C2‐pyridines has been developed using catalyst‐free [4+2] cycloaddition of 1,2,4‐triazines and in situ generated acetylene or labeled acetylene. Calcium carbide and water or deuterium oxide were used for the in situ generation of acetylene and dideuteroacetylene. Calcium carbide‐13C2 in the mixture with water or deuterium oxide was applied as 13C2‐acetylene and D2‐13C2‐acetylene source. [ABSTRACT FROM AUTHOR]

13C-Carbon is the most available source of carbon-13. It is a relatively inexpensive solid material, which can be easily converted to calcium carbide-13C2. In current work, Ca13C2 was used for in situ generation of 13C2-acetylene in 1,3-dipolar cycloaddition and [4+2] cycloaddition reaction. For the first time, 1H-1,2,3-triazoles-4,5-13C2 and isoxazoles-4,5-13C2 were synthesized using calcium carbide-13C2. A Diels-Alder type cycloaddition of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine and Ca 13C2 was investigated, and the best way for the synthesis of 3,6-di(pyridin-2-yl)pyridazine-4,5-13C2 was proposed for the first time. Here we perform a detailled description of NMR spectra of 13C2-labeled triazoles, isoxazoles and 3,6-di(pyridin-2-yl)pyridazine. [ABSTRACT FROM AUTHOR]

A tangible substituent effect may be perceived as a good feature in developing an organic reaction. This work demonstrates that, on the contrary, a zero‐slope Hammet plot should be sought. The synthesis of isoxazoles by consecutive cycloaddition of nitrile oxides to vinyl ethers and alcohols elimination was studied computationally and experimentally. We performed a Hammett study in silico to demonstrate a negligible substituent effect (i. e., broad substrate scope) in the addition of benzyl vinyl ether to nitrile oxides. The modeling was performed at the ωB97X‐V/def2‐TZVP//PBE0‐D4/def2‐TZVP+SMD(benzene) level of theory within the RIJCOSX approximation. The experimental evaluation validated the computational model. A versatile methodology for synthesizing substituted isoxazolines and isoxazoles was proposed as the main result. We present this work as a successful example of how quantum chemical modeling can re‐boost the classic Hammett approach to the optimization and design of organic synthetic methodologies. We anticipate further Hammett studies in silico, considering the current trend for data‐driven chemical research. [ABSTRACT FROM AUTHOR]

In this work, an universal synthetic approach for the synthesis of D2‐labeled nitrogen heterocycles based on cycloaddition reactions of in situ generated dideuteroacetylene is reported. A key feature of this method is the use of 1,4‐dioxane as a deuterium‐exchange‐proof solvent, which allowed the access to dideuterosubstituted heterocycles in up to 99 % deuteration degree. The method was demonstrated to be suitable for the synthesis of D2‐labeled triazoles, isoxazoles, pyrazoles and pyridazines. [ABSTRACT FROM AUTHOR]

Acetylene is a key building block for organic chemistry and potentially can be involved in a diverse range of synthetic transformations. However, critical analysis of practical considerations showed that application of gaseous acetylene in regular synthetic labs encounters a number of difficulties. Safety limitations due to flammable and explosive nature of gaseous acetylene and requirements for specialized high‐pressure equipment impose serious drawbacks. Typical reaction conditions involve excess of gaseous reactant, which is simply released to the atmosphere at the end of the reaction, thus generating waste and causing contamination. Calcium carbide brings a new green and sustainable wave into powerful alkyne transformations and significantly expands the repertoire of traditional acetylene chemistry. The novel trend of using calcium carbide instead of gaseous acetylene is synthetically beneficial and opens a novel reactivity for the C≡C unit. This review highlights recent advances in carbide chemistry, demonstrates its advantages and prospects in term of green synthetic approach. [ABSTRACT FROM AUTHOR]

A novel synthetic path to 1,3‐disubstituted pyrazoles and their deuterated derivatives was developed. It is based on the reaction of vinyl ethers with hydrazonoyl chlorides in the presence of triethylamine. The reaction mechanism, clarified by the joint experimental and computational study, involves 1,3‐dipolar cycloaddition of the in situ generated nitrile imines to vinyl ethers and subsequent cleavage of alcohol from the formed alkoxypyrazoline. The results highlight the possibility of using vinyl ethers as acetylene surrogate and provide a novel access to pyrazoles, 4,5‐dideuteropyrazoles and their regioselectively labeled derivatives, 5‐deuteropyrazoles. [ABSTRACT FROM AUTHOR]

Polyelectrolyte (PE) and nanocomposite (NC) microcapsules fabricated by layer-by-layer technique have been of great interest in the past decade as novel entities for cargo encapsulation and delivery as well as for diagnostic purposes. The unique physicochemical properties of polymers and inorganic nanoparticles used in layer-by-layer synthesis of PE and NC microcapsules make them promising in various fields, such as storage, catalysis, cells imaging, controlled drug release, and targeted drug delivery. However, the requirement of the cargo encapsulation is that the cargo should have a relatively large molecular weight in order to avoid the leakage from the capsules. In this review, recent progress in the design and functionalization of PE and NC microcapsules using sol-gel method for storage of small cargos have been presented. Moreover, various remote exposures on the permeability of organic/inorganic composite microcapsule shells such as ultrasound, magnetic field gradient, laser, and microwave radiation have been observed. Finally, the description and discussion of the new trends and perspectives for improved functionality of PE microcapsules are the major topic of this progress report. [ABSTRACT FROM AUTHOR]

Anxiolytic afobazole (5-Ethoxy-2-[2-(morpholino)-ethylthio]benzimidazole dihidrochloride) has pronounced ligand properties toward Sigma-1 receptor ( σ1 receptor,SigmaR1) and MT3 receptors. Our previous work demonstrated that afobazole possess cytoprotective effect in the in vitro model of menadione genotoxicity (Woods et al. ) through interaction with MT3 receptor (Kadnikov et al. ). Present study utilized previously described models to address the contribution of SigmaR1 to cytoprotective action of afobazole. The reduction in afobazole cytoprotective effect observed after preincubation of cell suspension with selective SigmaR1 antagonist BD-1047 revealed an important contribution of SigmaR1 in afobazole-mediated effect. We confirmed our observation using selective SigmaR1 agonist PRE-084. We conclude that pronounced cytoprotective effect of afobazole over PRE-084 is likely achieved by additive SigmaR1 and MT3-mediated effects. [ABSTRACT FROM AUTHOR]

The thermal transformation of different alk-1-enyl-N-phthalimidoaziridines depends strongly on their substitution pattern. [ABSTRACT FROM AUTHOR]

An abstract of the article "Fetal nuchal translucency in 26912 uncomplicated pregnancies in Saint Petersburg, Russia," by I. Chubkin and colleagues are presented.

An abstract of the article "Fetal size charts for 10-14 weeks of gestation in Saint Petersburg. Reference values of head and abdomen circumference, femur length and fetal heart rate," by I. Chubkin and colleagues is presented.

An abstract of the article "Prenatal diagnostics of congenital malformations of the respiratory tract. The main findings over the period of 20 years," by S. Puyda, D.V. Voronin, and K. Karpov is presented.

An abstract of the article "Gastric duplication cysts: case report," by I. Chubkin and D. V. Voronin is presented.

An abstract of the conference paper "Prenatal diagnosis and postnatal outcomes in fetuses with vein of Galen malformation," by D.V. Voronin and colleagues is presented.

An abstract of the conference paper "The natural history and postnatal outcomes in fetuses with isolated choroid plexus cysts found at prenatal ultrasound scan in a single referral centre," by D. V. Voronin and colleagues is presented.