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

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

Характеристика биохимического состава и антиоксидантной активности Spinacia oleracea L. и Spinacia turkestanica Iljin.: сравнительное исследование

Spinach is an economically important vegetable crop widely cultivated and consumed worldwide. This early ripening leafy vegetable is rich in bioactive components, fiber, micro and macro elements, vitamins, and has high antioxidant activity. Results of numerous studies on the effects of spinach on human health confirm its beneficial effect. The species S. oleracea L. is cultivated commercially. The ancestor of cultivated spinach is S. turkestanica Iljin, which has a breeding potential for different economically valuable traits. Its biochemical composition has been studied extremely little. The present article offers a comparative evaluation of the biochemical profile and antioxidant activity of cultivated and wild spinach species. The material for the study was a representative sample of 48 collection accessions of spinach from the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR). The accessions were grown in 2019 and 2020 in the open ground of the Pushkin and Pavlovsk Laboratories of VIR. The antioxidant activity was studied spectrophotometrically by the DPPH assay of free radical scavenging at a wavelength of 515 nm. A significant similarity of the two species in most biochemical parameters was revealed, which confirms their phylogenetic relationship. Significant differences were found in the content of phenolic elements, which determine the elevated values of antioxidant and antiradical activity of S. turkestanica. The article presents correlation matrices of species biochemical composition, describes general trends, negative relationships and conjugated factors. The identified promising accessions of both cultivated and wild spinach are recommended for breeding for increased content of phenolic compounds, ascorbic acid and antioxidant activity. The result of the study helps to reveal the potential of the crop as a valuable source of bioactive components and high antioxidant activity.Шпинат - экономически значимая овощная культура, широко возделываемая и потребляемая во всем мире. Этот скороспелый листовой овощ богат биологически активными компонентами, клетчаткой, микро- и макроэлементами, витаминами, обладает высокой антиоксидантной активностью. Многочисленные результаты изучения влияния шпината на здоровье человека подтверждают его благотворное действие. В производстве культивируют вид S. oleracea L. Прародителем культурного вида шпината является вид S. turkestanica Iljin., обладающий потенциалом для селекции по различным хозяйственно-ценным признакам. Его биохимический состав изучен крайне мало. В настоящей работе дана сравнительная оценка биохимического профиля и антиоксидантной активности культурного и дикого видов шпината. Материалом для исследования послужила репрезентативная выборка из 48 образцов коллекции шпината ВИР. Образцы выращивались в 2019 и 2020 году в условиях открытого грунта Пушкинских и Павловских лабораторий Всероссийского института генетических ресурсов растений имени Н.И. Вавилова. Антиоксидантную активность изучали методом DPPH на спектрофотометре путем поглощения свободных радикалов раствора, измеряемое при длине волны 515 нм. Выявлено значительное сходство двух видов по большинству биохимических показателей, что подтверждает их филогенетическое родство. Существенные различия обнаружены в содержании фенольных элементов, определяющих повышенные значения антиоксидантной и антирадикальной активности S. turkestanica Iljin. В статье приведены корреляционные матрицы видового биохимического состава, описаны общие тенденции, отрицательные взаимосвязи и сопряженные факторы. Выделившиеся перспективные образцы как культурного, так и дикого видов шпината рекомендованы для селекции на увеличение содержания фенольных соединений, аскорбиновой кислоты и антиоксидантной активности. Результат исследования помогает раскрыть потенциал культуры, как ценного источника биологически-активных компонентов и высокой антиоксидантной активности

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

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

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

Cellular internalisation, bioimaging and dark and photodynamic cytotoxicity of silica nanoparticles doped by {Mo₆I₈}⁴⁺ metal clusters

Silica nanoparticles (SNPs) doped by hexanuclear molybdenum cluster complexes [{Mo₆X₈}L₆]n (X = Cl, Br, or I; L = various inorganic or organic ligands) have been recently suggested as materials with a high potential for biomedical applications due to both the outstanding photoluminescent properties and the ability to efficiently generate singlet oxygen upon photoirradiation. However, no studies were undertaken so far to prove this concept. Therefore, here we examined the potential of photoluminescent SNPs doped by {Mo₆I₈}⁴⁺ for such applications as bioimaging and photodynamic therapy using human epidermoid larynx carcinoma (Hep-2) cell line as a model. Our results demonstrated both: (i) significant luminescence from cells with internalised molybdenum cluster doped SNPs combined with the low cytotoxicity of particles in the darkness and (ii) significant cytotoxicity of the particles upon photoirradiation. Thus, this research provides strong experimental evidence for high potential of molybdenum cluster doped materials in such biomedical applications as optical bioimaging, biolabeling and photodynamic therapy

Preseismic ULF effectand possible interpretation

We present the results of ULF magnetic field observation at Karimshino station (Kamchatka, Russia). Using a case study we discovered an effect of suppression of ULF intensity about 2-6 days before rather strong and isolated seismic shocks (magnitude M = 4.6-6.6). It is revealed for nighttime and the horizontal component of ULF field (G) in the frequency range 0.01-0.1 Hz. Then we prove the reliability of the effect by computed correlation between G (or 1/G) and especially calculated seismic indexes Ks for the rather long period of observation from June 2000 to November 2001. Our recent data confirm the validity of the effect. We show here a similar result during a period of frequent strong seismic activity in April-May 2002. It is highly probable that the effect observed is connected with the increase in plasma density perturbations inside the ionosphere, which are induced by preseismic water and gas release at the ground surface and following energy transportation into the ionosphere by atmospheric gravity waves. Two models are discussed and computed: the first is a decrease of penetration coefficient of Alfven waves from the magnetosphere due to a turbulent increase in effective Pedersen conductivity in the ionosphere, and the second is a change in wave number (k) distribution of source ionospheric turbulence. One of the mechanisms or both could be responsible for the observed 2-3 times suppression of ULF magnetic field noise at the ground

Near-seismic effects in ULF fields and seismo-acoustic emission: statistics and explanation

International audiencePreseismic intensification of fracturing has been investigated from occurrence analysis of seismo-acoustic pulses (SA foreshocks) and ULF magnetic pulses (ULF foreshocks) observed in Karimshino station in addition to seismic foreshocks. Such analysis is produced for about 40 rather strong and nearby isolated earthquakes during 2 years of recording. It is found that occurrence rate of SA foreshocks increases in the interval (-12, 0 h) before main shock with 3-times exceeding of background level in the interval (-6, -3 h), and occurrence probability of SA foreshocks (pA~75%) is higher than probability of seismic foreshocks (ps~30%) in the same time interval.ULF foreshocks are masked by regular ULF activity at local morning and daytime, nevertheless we have discovered an essential ULF intensity increase in the interval (-3, +1 h) at the frequency range 0.05-0.3 Hz. Estimated occurrence probability of ULF foreshocks is about 40%. After theoretical consideration we conclude: 1) Taking into account the number rate of SA foreshocks, their amplitude and frequency range, they emit due to opening of fractures with size of L=70-200 m (M=1-2); 2) The electro-kinetic effect is the most promising mechanism of ULF foreshocks, but it is efficient only if two special conditions are fulfilled: a) origin of fractures near fluid-saturated places or liquid reservoirs (aquifers); b) appearance of open porosity or initiation of percolation instability; 3) Both SA and ULF magnetic field pulses are related to near-distant fractures (r<20-30 km); 4) Taking into account number rate and activation period of seismic, SA and ULF foreshocks, it is rather probable that opening of fractures and rupture of fluid reservoirs occur in the large preparation area with horizontal size about 100-200km

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