Divergent Transformations of 2‑Nitro‑1<i>H</i>‑benzo[<i>f</i>]chromenes in Reactions with Alkylidenemalononitriles: Access to Naphtho[2,1‑<i>b</i>]furans via Base-Mediated Pyran Ring Contraction

The action of 2-(1-arylethylidene)malononitriles on 2-nitro-1H-benzo[f]chromenes in the presence of Et3N and MoO3·2H2O results in naphtho[2,1-b]furans containing an allylidenemalononitrile unit in the α-position. The reaction proceeds with contraction of the pyran ring via a cascade carba-Michael addition/retro-oxa-Michael reaction/tautomerization/SN2/oxidation process. In contrast, the reaction of 2-nitro-1H-benzo[f]chromenes with the cyclic Knoevenagel adduct derived from 1-indanone and malononitrile leads to dihydroindeno[1,2-c]xanthenes. The possibility of further transformations of naphtho[2,1-b]furan derivatives as useful precursors and their optical properties were also investigated

Confirmation studies of Soviet research on immunological effects of microwaves: Russian immunology results

International audienceThis paper presents the results of a replication study performed to investigate earlier Soviet studies conducted between 1974 and 1991 that showed immunological and reproductive effects of long-term low-level exposure of rats to radiofrequency (RF) electromagnetic fields. The early studies were used, in part, for developing exposure standards for the USSR population and thus it was necessary to confirm the Russian findings. In the present study, the conditions of RF exposure were made as similar as possible to those in the earlier experiments: Wistar rats were exposed in the far field to 2450 MHz continuous wave RF fields with an incident power density in the cages of 5 W/m2 for 7 h/day, 5 days/week for a total of 30 days, resulting in a whole-body SAR of 0.16 W/kg. Effects of the exposure on immunological parameters in the brain and liver of rats were evaluated using the complement fixation test (CFT), as in the original studies, and an additional test, the more modern ELISA test. Our results, using CFT and ELISA, partly confirmed the findings of the early studies and indicated possible effects from non-thermal RF exposure on autoimmune processes. The RF exposure resulted in minor increases in formation of antibodies in brain tissue extract and the exposure did not appear to be pathological. In addition, a study was conducted to replicate a previous Soviet study on effects from the injection of blood serum from RF-exposed rats on pregnancy and foetal and offspring development of rats, using a similar animal model and protocol. Our results showed the same general trends as the earlier study, suggesting possible adverse effects of the blood serum from exposed rats on pregnancy and foetal development of intact rats, however, application of these results in developing exposure standards is limited. Bioelectromagnetics 31:589-602, 2010. © 2010 Wiley-Liss, Inc

Trace Elements in Sediments of Two Lakes in the Valley of the Middle Courses of the Ob River (Western Siberia)

Lake sediments accumulate various pollutants and act as efficient natural archives suitable for reconstruction the environmental conditions of the past. In contrast to fairly good knowledge of mineral sediments in lakes of European and North America boreal lakes, Siberian lakes of the boreal zone remain quite poorly studied. In this work, two cores of lake sediments of the Ob River valley were investigated. Elemental analyses were carried out on the sediments, losses on ignition were determined, and the rate of sedimentation was measured from the activity of Pb-210 and Cs-137. According to the content of organic matter, bottom sediments belong to different types: clastic (Lake Inkino, located in the Ob River floodplain) and organogenic (Lake Shchuchie on the second terrace). The rate of sedimentation in Lake Shchuchie is several times higher than that in Lake Inkino. The sediments of Lake Inkino are similar in composition (including the pattern of rare earth elements) to the suspended particulate matter of the Ob River as well as to average detrital matter of the upper continental crust. Sediments of Lake Shchuchie (sapropels) are enriched in a number of heavy metals. Based on the elemental composition, signs of diagenetic processes and authigenic mineral formation were determined, such as accumulation of carbonates and the formation of manganese oxides and hydroxides. There is an enhanced recent input of Cr, Co, Cu, Zn, Cd, Sb, Pb, and Bi in the upper layers of sediments as a result of atmospheric anthropogenic pollutant deposition

Trace Elements in Sediments of Two Lakes in the Valley of the Middle Courses of the Ob River (Western Siberia)

Lake sediments accumulate various pollutants and act as efficient natural archives suitable for reconstruction the environmental conditions of the past. In contrast to fairly good knowledge of mineral sediments in lakes of European and North America boreal lakes, Siberian lakes of the boreal zone remain quite poorly studied. In this work, two cores of lake sediments of the Ob River valley were investigated. Elemental analyses were carried out on the sediments, losses on ignition were determined, and the rate of sedimentation was measured from the activity of Pb-210 and Cs-137. According to the content of organic matter, bottom sediments belong to different types: clastic (Lake Inkino, located in the Ob River floodplain) and organogenic (Lake Shchuchie on the second terrace). The rate of sedimentation in Lake Shchuchie is several times higher than that in Lake Inkino. The sediments of Lake Inkino are similar in composition (including the pattern of rare earth elements) to the suspended particulate matter of the Ob River as well as to average detrital matter of the upper continental crust. Sediments of Lake Shchuchie (sapropels) are enriched in a number of heavy metals. Based on the elemental composition, signs of diagenetic processes and authigenic mineral formation were determined, such as accumulation of carbonates and the formation of manganese oxides and hydroxides. There is an enhanced recent input of Cr, Co, Cu, Zn, Cd, Sb, Pb, and Bi in the upper layers of sediments as a result of atmospheric anthropogenic pollutant deposition

Molecular mechanisms of adaptation to the habitat depth in visual pigments of A. subulata and L. forbesi squids: on the role of the S270F substitution

Revealing the mechanisms of animal adaptation to different habitats is one of the central tasks of evolutionary physiology. A particular case of such adaptation is the visual adaptation of marine species to different depth ranges. Because water absorbs more intensively longer wavelengths than shorter wavelengths, the increase of habitat depth shifts the visual perception of marine species towards the blue region. In this study, we investigated the molecular mechanisms of such visual adaptation for two squid species – Alloteuthis subulata and Loligo forbesi. These species live at different depths (200 m and 360 m, respectively) and the absorption maximum of A. subulata visual rhodopsin is slightly red-shifted compared to L. forbesi rhodopsin (499 and 494 nm, respectively). Previously, the amino acid sequences of these two species were found to differ in 22 sites with only seven of them being non-neutral substitutions, and the S270F substitution was proposed as a possible candidate responsible for the spectral shift. In this study, we constructed computational models of visual rhodopsins of these two squid species and determined the main factors that cause the 5 nm spectral shift between the two proteins. We find that the origin of this spectral shift is a consequence of a complex reorganization of the protein caused by at least two mutations including S270F. Moreover, the direct electrostatic effect of polar hydroxyl-bearing serine that replaces non-polar phenylalanine is negligible due to the relatively long distance to the chromophore

Ultrasonography of the larynx for diagnosis of the vocal folds mobility impairment

Purpose. To study a possibility of performance and diagnostic accuracy of ultrasonography (US) of a larynx in identification of motility disorders of VF (vocal folds) in comparison with the laryngoscope which is traditionally applied for this purpose. Materials and methods. According to the objectives of the study, two patient groups were formed. In first group of patients (n = 466) we studied acceptability of ultrasonografy to discriminate various laryngeal structures. In second group of patient (n = 432) we evaluated the diagnostic accuracy of ultrasonography in point of detection of vocal muscles paresis. Results. Laryngeal structures were available to examination by ultrasound (without taking in account age and sex) in 92.7% of patients. Two patterns have been identified in the course of this part of the study: deterioration of visibility of the vocal folds with increasing patient age and better visibility of the vocal folds in women than in men. According to the comparative analysis, ultrasonography accuracy rate (in those patients who had had clearly visible vocal folds during ultrasonography) did not differ from that during videolaryngoscopy. Conclusion. During the conducted research it was found that the US of the larynx is an effective and perspective method for detection of a paresis of VF with sensitivity and specificity 93,55% and 100% respectively. Among those patients whoapos; VF are available to ultrasound evaluation the accuracy of method is comparable with a videolaryngoscopy and can be used with success in daily work of units of endocrine surgery

Past and Future of Permafrost Monitoring: Stability of Russian Energetic Infrastructure

This study is an attempt to suggest a new state system of permafrost monitoring, primarily for energetic infrastructure, based on past approaches and achievements in Russia for over a hundred years of Arctic studies. The methodology of this study is based on general theoretical methods of scientific research. Historical (retrospective analysis of the development of the monitoring system of long-term permafrost in Russia) and logical (inductive generalization) methods were applied. The structure and methods of permafrost monitoring in the Soviet Union and new technologies used nowadays to establish permafrost monitoring systems, taking into account modern Arctic energetic development, have been analyzed