1,996 research outputs found

    THIACALIX[4]ARENES DERIVATIVES: FROM SELF-ASSEMBY TO FUNCTIONAL MATERIALS

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    This work was supported by the by Russian Science Foundation, project # 19-13-00095

    Wiring surface loss of a superconducting transmon qubit

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    Quantum processors using superconducting qubits suffer from dielectric loss leading to noise and dissipation. Qubits are usually designed as large capacitor pads connected to a non-linear Josephson junction (or SQUID) by a superconducting thin metal wiring. Here, we report on finite-element simulation and experimental results confirming that more than 50% of surface loss in transmon qubits can originated from Josephson junctions wiring and can limit qubit relaxation time. Extracting dielectric loss tangents capacitor pads and wiring based on their participation ratios, we show dominant surface loss of wiring can occur for real qubits designs. Then, we simulate a qubit coupled to a bath of individual TLS defects and show that only a small fraction (~18%) of coupled defects is located within the wiring interfaces, however, their coupling strength is much higher due to stronger electromagnetic field. Finally, we fabricate six tunable floating transmon qubits and experimentally demonstrate up to 20% improvement in qubit quality factor by wiring design optimization.Comment: 17 pages, 8 figure

    Luminescent coordination polymers based on Ca²⁺ and octahedral cluster anions [{M₆Clⁱ₈}Clᵃ₆}²⁻ (M = Mo, W) : synthesis and thermal stability studies

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    Luminescent coordination polymers (CPs) based of inexpensive stable precursors are attractive materials for applications. Here we report the synthesis and evaluation of the stability and photophysical characteristics of the first examples of phosphorescent CPs based on octahedral molybdenum and tungsten cluster anions. Specifically 1D CP trans-[{Ca(OPPh₃)₄}{{M₆Clⁱ₈}Clᵃ₆}]∞ (M = Mo, W) can be obtained either directly at increased temperature or via intermediate phases [cis-Ca(OPPh₃)₄(H₂O)₂][{M₆Clⁱ₈}Clᵃ₆]∙2CH₃CN that are stable at room-temperature, but convert to the titled CP at temperatures above 100 °C

    Coordination Polymers based on calixarene derivatives: Structures and properties

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    © 2017 Elsevier B.V. The solid-state structures of 1D–3D Coordination Polymers based on the macrocyclic calixarene backbone have been reviewed, based on the chemical nature of appended substituents on the macrocycle platform. The coordination propensity of this class of ligands is analysed, taking into account the different coordinating atoms/groups that can be located on the macrocyclic ligand: (1) the unmodified inherently coordinating thiacalix[4]arene with the S bridges as donor atoms; (2) different conformations of calix[n] arene units, with appended O donor atoms; (3) the chemical modification of the upper rim of calix[n]arenes and thiacalix[n] arenes, with coordinating groups, in particular the use of the sulfonate groups; (4) calix[4]arenes, thiacalix[4] arenes and tetramercaptothiacalix[4]rene that have been modified at their lower rim (mono, di and tetra substitution) with coordinating groups like cyano, carboxylate, pyridyl and pyrazolyl groups. All the formed coordination networks have been described. A special attention has been drawn to the structural and functional properties of these extended networks: magnetic, luminescence, adsorption and catalytic properties. Perspectives and future challenges in this emerging field are also discussed

    Main Directions of Environmental Policy of Greenland at Beginning of XXI Century

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    The individual directions of Greenland’s environmental policy, which have the greatest impact on the modern ecological situation in the autonomy, are considered. The authors of the work referred to these areas as energy, water resources, waste disposal and pollution control. A description of the development of the selected ecological directions is given, an analysis of their current state is carried out. Greenland’s environmental cooperation with Denmark and the European Union is also analyzed. The basis of the source study base of the article is the Greenlandic legislation in the field of ecology. The main documents, programs and cases that influenced the development of the selected environmental directions are considered. The relevance of this article lies in a detailed examination of the environmental policy of Greenland and the construction of general conclusions about the environmental situation of the Danish Autonomous Territory based on the results obtained in the analysis of individual environmental areas. The novelty of the study is seen in an integrated approach to the analysis of the ongoing environmental policy of Greenland. The main positive and negative results in the selected environmental areas are noted. An assumption is made about the ambiguity of the environmental policy of Greenland, and possible outcomes in the implementation of this policy are considered

    Calixarene-based supramolecular systems: a platform for nanomaterials design by self-assembly

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    Lower rim thiacalix[4]arenes derivatives in cone and 1,3-alternate conformations have many advantages to create a wide range of precursors for the design of very sophisticated supramolecular architectures. These compounds can be considered as technological platform for nanomaterials design by self-assembly method. Particular attention will be paid to the application of calixarene derivatives for the construction of various supramolecular and nanosystems, devices and smart materials: colloid nanoparticles, catalytic systems, metalcoordinated networks, Langmuir-Blodgett nanolayers, molecular magnets etc.The authors gratefully acknowledge of the RSF (19-13-00095 and 18-73-10033) for the financial support

    Effectiveness of mindfulness-based therapy, stress reduction in hypertension and prehypertension: a systematic review

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    Aim. To collect and analyze currently available clinical studies on the effectiveness of mindfulness-based stress reduction (MBSR) for lowering blood pressure in individuals with normal, high normal blood pressure and hypertension.Material and methods. The systematic review was prepared according to the PRISMA algorithm with minor modifications. The search algorithm included articles in Russian and English, indexed in the Pubmed/MEDLINE and Cochrane Library databases. The study included studies on the impact of mindfulness interventions on blood pressure levels in individuals aged ≥18 years with an established diagnosis of hypertension, with normal (120-129/80-84 mm Hg) and high normal office blood pressure (130-139/85-89 mm Hg).Results. A total of 4785 publications were identified and included in the study, of which, after a multistage sampling, including screening of articles, 6 studies were included in a qualitative systematic review.Conclusion. Qualitative synthesis of the results of clinical studies revealed that the evidence currently available indicates a possible positive effect of mindfulness interventions on blood pressure levels in individuals with normal, high normal blood pressure and hypertension. However, further studies with larger samples and measurement of more primary and secondary endpoints are required

    Mobile applications for anxiety and stress reduction: potential for preventing noncommunicable diseases

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    The article discusses using mobile applications for smartphones as tools to reduce anxiety and stress. The modern views on pathogenesis of the relationship between stress, anxiety disorders and cardiovascular disease are considered. Based on a review of some representative studies, a methodology for evaluating the characteristics and functions of mobile applications for managing anxiety and stress symptoms is proposed. The applications selected for analysis were tested according to this methodology. There are following key features of the Russianlanguage field of mobile applications for anxiety and stress reduction: a small number of applications, high prevalence of using breathing exercises, meditations and sound therapy, an extremely low disease specificity and focus mainly on helping with general symptoms of anxiety

    Biochemical composition of tomato fruits of various colors

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    Tomato (Lycopersicon esculentum Mill.) is an economically important and widely cultivated vegetable crop that is consumed both fresh and processed. The nutritional value of tomato fruits is related to the content of carotenoids, polyphenols, sugars, organic acids, minerals and vitamins. Currently, there is a growing interest in the qualitative and quantitative increase in the content of health-promoting compounds in tomato fruits. VIR Lycopersicon (Tourn.) Mill. genetic resources collection includes 7678 accessions of one cultivated and nine wild species, which in turn provides ample opportunities for searching for information on the variability of the content of biologically active substances and searching for sources with a high content of them in the gene pool. Our work presents the results of the study of 70 accessions of cultivated and wild tomato on the main biochemical characteristics: the content of dry matter, ascorbic acid, sugars, carotenoids, chlorophylls and anthocyanins. As the basis for the selection of accessions for the study, accessions with various colors of fruits, including new accessions with varying content of anthocyanin, were taken. As a result of this study, the amplitude of variability in the content of dry matter (3.72–8.88 and 9.62–11.33 %), sugars (1.50–5.65 and 2.20–2.70 %), ascorbic acid (12.40–35.56 and 23.62– 28.14 mg/100 g), titratable acidity (0.14–0.46 and 0.33–0.48 %), chlorophylls (0.14–5.11 and 2.95–4.57 mg/100 g), carotenoids (0.97–99.86 and 1.03–10.06 mg/100 g) and anthocyanins (3.00–588.86 and 84.31–152.71 mg/100 g) in the fruits of cultivated and wild tomatoes, respectively, was determined. We have determined correlations between the content of dry matter and monosaccharides (r = 0.40, p ≤ 0.05), total sugars (r = 0.37, p ≤ 0.05) and ascorbic acid (r = 0.32, p ≤ 0.05); the content of ascorbic acid and carotenoids (r = 0.25, p ≤ 0.05). A high dependence of the content of chlorophyll a and b among themselves (r = 0.89, p ≤ 0.05), as well as between the content of chlorophyll b and anthocyanins (r = 0.47, p ≤ 0.05), the content of β-carotene (r = 0.26, p ≤ 0.05) and the content of monosaccharides (r = –0.29, p ≤ 0.05) has been noted. We have identif ied tomato accessions with a high content of individual chemical substances, as well as with a complex of traits that can be used as sources in breeding for a high content of dry matter, sugars, ascorbic acid, pigments and anthocyanins
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