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

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

Anomalies of LF signal during seismic activity in November?December 2004

International audienceA signal transmitted by Japan Time Standard LF station (40 kHz, Fukushima prefecture) and recorded in Petropavlovsk-Kamchatski (Russia) is analyzed during a time interval from 1 July 2004 till 24 January 2005. This interval is characterized by quiet seismic conditions up to the beginning of November, but rather strong seismic activity occurs in November and December not far from Hokkaido (Japan) and in the region of northern Kuril Islands. There were three series of earthquakes with M=5.6?7.1 in a zone of sensitivity of our wave path during two months. Nighttime "bay-like" phase and amplitude anomalies of the LF signal are observed several days before and during every series of earthquakes. During the whole period of seismic activity a significant shift in terminator times is also evident. The spectrum of LF seismo-induced anomalies shows a clear increase for the period of about 25 min

Effectiveness of legislative changes obligating notification of prolonged sickness absence and assessment of remaining work ability on return to work and work participation : a natural experiment in Finland

Objectives Policies have been introduced to reduce sickness absence, but their effectiveness is largely unknown. In a natural experiment, we examined effects of legislative changes on return to work and work participation. Methods The source population consisted of up to 72164 Finnish public sector employees with a permanent job contract in 2008-2011 (before) and in 2013-2014 (after). We used employees with a continuous sickness absence of at least 30 calendar-days (n=5708-6393), 60 compensated days (n=1481-1655) and 90 compensated days (n=766-932). We examined sustainable return to work (a minimum of 28 consecutive working days) with survival analysis as well as monthly work participation after a sickness absence, and annual gain in work participation after the intervention, using trajectory analyses. Results Sustainable return to work after 60days of sickness absence occurred earlier after the legislative changes (p value 0.017), although the effect reduced towards the end of the follow-up. There were no differences in return to work after a 30 or 90days of sickness absence. The largest annual gain, postintervention versus preintervention, in monthly work participation was observed among employees with 60days of sickness absence and was 230.9 person-years/10000 employees. The corresponding annual gains among those with 30days and 90days of sickness absence were 51.8 and 39.6, respectively. Conclusions Our findings suggest that the legislative changes, obligating early notification of prolonged sickness absences as well as assessment of remaining work ability and possibilities to continue working, may enhance sustainable return to work in the short term. Other measures will be needed to enhance work participation, especially in the long term.Peer reviewe

Thiacalix[4]arene’s lower rim derivatives: Synthesis and supramolecular properties

© ISUCT Publishing. A consolidated review on the synthesis of lower rim tetrasubstituted thiacalixarenes and their self-assembly on the soft surfaces contributed from our group is presented. The approaches for the synthesis of different types of tetra-O-substituted thiacalixarenes from the last 10 years are discussed. In addition, amphiphilic macrocycles in 1,3-alternate conformation form monolayers at the interface and are effectively embedded into the vesicles. Decorated by thiacalixarenes nanolayers and vesicles demonstrate a high selectivity towards specific analytes

Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre-Polar Urals, northeast European Russia

This study investigated Holocene tree-line history and climatic change in the pre-Polar Urals, northeast European Russia. A sediment core from Mezhgornoe Lake situated at the present-day alpine tree-line was studied for pollen, plant macrofossils, Cladocera and diatoms. A peat section from Vangyr Mire in the nearby mixed mountain taiga zone was analysed for pollen. The results suggest that the study area experienced a climatic optimum in the early Holocene and that summer temperatures were at least 2°C warmer than today. Tree birch immigrated to the Mezhgornoe Lake area at the onset of the Holocene. Mixed spruce forests followed at ca. 9500-9000 14C yr BP. Climate was moist and the water level of Mezhgornoe Lake rose rapidly. The hypsithermal phase lasted until ca. 5500-4500 14C yr BP, after which the mixed forest withdrew from the Mezhgornoe catchment as a result of the climate cooling. The gradual altitudinal downward shift of vegetation zones resulted in the present situation, with larch forming the tree-line

Coordination Polymers based on calixarene derivatives: Structures and properties

© 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

Wiring surface loss of a superconducting transmon qubit

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

The effect of the August 21, 2017 total solar eclipse on the phase of VLF/LF signals

An experimental study of the phase and amplitude observations of sub‐ionospheric very low and low frequency signals is performed to analyse the response of the lower ionosphere during the August 21, 2017 total solar eclipse in the United States of America. Three different sub‐ionospheric wave paths are investigated. The length of the paths varies from 2200 to 6400 km and the signal frequencies are 21.4 kHz, 25.2 kHz and 40.75 kHz. The two paths cross the region of the total eclipse and the third path is in the region of 40‐60% of obscuration. None of the signals reveal any noticeable amplitude changes during the eclipse while negative phase anomalies (from ‐33° to ‐95°) are detected for all three paths. It is shown that the effective reflection height of the ionosphere in low and middle latitudes is increased by about 3‐5 km during the eclipse. Estimation of the electron density change in the lower ionosphere caused by the eclipse, using linear recombination law, shows that the average decrease is by 2.1 to 4.5 times

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

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