Search

Assessing the functional level of children with severe cerebral palsy (CP) requires sensitive tools. In this study, an 'assessment tool' was developed based on the Test of Infant Motor Performance (TIMP) for this population and the reliability and validity evaluated. Five physical therapists administered the 'assessment tool' to six children (3-6 years old with a diagnosis of CP, GMFCS Level V). Subtest I of the Gross Motor Function Measure (GMFM-88) was also administered. Intra- and inter-rater reliability were assessed, and the concurrent validity between the 'assessment tool' and GMFM-88 calculated. The intra-rater reliability, a comparison of the total scores on the 'assessment tool' (live test) and the videotaped rescoring of the same test one month later showed consistency among four of the five therapists (ICC =0.7545 to 0.979). The inter-rater reliability varied on some of the items but the total score on the 'assessment tool' showed good reliability (ICC 0.816). Scores of children with dyskinesia were less stable. The Spearman's rank correlation coefficient was not significant. Therapists provided recommendations for item revisions. Further development of an 'assessment tool' appears justified; a larger study using a version with revised administration guidelines and items should be undertaken to re-verify the psychometrics properties of the 'assessment tool.'

The quality of steam produced by boilers is strictly standardized and must be maintained whatever the quality of makeup water and whatever the composition of the boiler unit’s thermal cycle equipment. Under the conditions of constantly improved instruments for chemical monitoring, it becomes possible to develop measurement systems using which the main standardized and diagnostic steam quality indicators can be monitored by measuring the electric conductivity and pH of cooled samples. Unlike boilers operating at a pressure of 13.8 MPa and higher, steam boilers for steam pressures equal to 9.8 and 3.9 MPa—and also industrial heat recovery steam generators—operate with steam that has a higher content of salts and carbon dioxide; in addition, it contains ammonia, which enters into steam from boiler water. Steam quality is often estimated using the two-quadrant nomographic chart of Mostofin, who proposed it more than 50 years ago. In using certain computation algorithms, it is possible to calculate the standardized and diagnostic steam quality indicators, such as concentrations of sodium, chlorides, ammonia, carbon dioxide, and salt content. The article presents an algorithm for estimating the concentrations of the above-mentioned impurities for cooled live steam samples of power-generating boilers operating at pressures below 10.0 MPa, and boilers for superhigh and supercritical pressures, and industrial heat recovery steam generators, including the combined-cycle power plant units. Examples of using the calculation procedure for analyzing the steam quality in industrial boilers are given.

The paper reports geochemical, geochronological (ID–TIMS zircon U–Pb) and isotope–geochemical (Nd, Pb) study of granitoids of the Kodar complex developed in the western part of the Aldan shield. It has been established that these rocks can be classified as postcollisional A–type rapakivi granites, which together with the mafic–ultramafic rocks of the Chinei complex compose a single magmatic association formed within 1876 ± 4–1859 ± 2 Ma. The massifs of this association are a part of the giant South Siberian magmatic belt over 2500 km in length, which was formed at the final stage (1.88–1.84 Ga) of evolution of the Paleoproterozoic orogen. Globally, this belt is the largest stitching suture, which marks the formation of the Siberian craton and its entrance into the Paleoproterozoic Nuna supercontinent. The formation of the initial magmas of the Kodar granitoids was related to the mantle–crustal interaction during the mixing of primary mafic mantle magmas or their derivatives with anatectic melts derived through partial melting of the Archean lower continental crust of the region under the thermal influence of mafic magma. The crustal component in the source clearly predominates and has a heterogeneous nature. The mantle component is mainly represented by ancient enriched mantle, with the possible contribution of the OIB–type component.

Granitoids of the Uda complex are distributed within the southeastern marginal part of the Siberian craton and its folded framing. Geochemical, isotope (Nd, Sr), and geochronological (U–Pb ID TIMS) studies of two massifs (Chalbuk-Yakon and Uyan-Tavitchak) of this complex of the Dzhugdzhur Block of the Stanovoy suture were carried out; the results are presented in this paper. It is found that formation of these massifs took place in the Early Cretaceous (116 ± 1 Ma) in the geodynamic setting of lithospheric extension. The initial magma for these granitoids was formed from a mixed source: Early Precambrian lower crust and mantle, with a clear predominance of the crustal component. The granitoids of the Uda complex of the Dzhugdzhur block most likely represent the eastern end of the Udsko-Zeya (Stanovoy) post-collision magmatic belt, stretching for more than 1000 km along the southern framing of the Siberian craton parallel to the Mongol–Okhotsk suture zone and stitching various tectonic blocks of the northeastern part of the Central Asian fold belt. There is every reason to believe that, further to the west, the Udsko-Zeya (Stanovoy) belt passes into the West Transbaikal rift system, the formation of which took place in the interval of 170–110 Ma. In other words, it can be assumed that in the Mesozoic, in the southern framing of the Siberian craton, there was a giant unified rift system stretching for more than 2000 km.

U-Pb dating of cassiterite and zircon from the Yazov granite (Transbaikalia region, Eastern Siberia, Russia) and cassiterite from spatially associated tin mineralization in the Tuyukan ore district in the Tonod uplift was conducted using in situ laser ablation inductively coupled plasma mass spectrometry. These analyses allow comparison of isotopic systematics for both minerals, especially related to transport in granitic magma. These data are also useful for understanding possible genetic links between the granite and the tin mineralization. Most of the U-Pb zircon analyses define a 206Pb/238U age of 719 ± 15 Ma for the granite; in addition, several zircon cores define an inheritance age of 1839 ± 21 Ma. U-Pb data for 10 nearly concordant analyses of disseminated cassiterite from the same samples yield a 206Pb/238U age of 1838 ± 34 Ma. This is the first documented evidence of cassiterite inheritance in granitic magma. These data indicate the robust character of U-Pb isotope systematics in cassiterite, comparable to that in zircon. The presence of numerous inclusions of cassiterite in zircon from the Yazov granite (revealed by nanotomography) supports the interpretation of inherited cassiterite included during Neoproterozoic zircon crystallization. The data indicate that high tin concentrations in the Yazov granite are due to the incorporation of older cassiterite crystals from country rock, not coeval cassiterite crystallization. Cassiterite samples from two ore occurrences spatially associated with the Yazov granite yield Pb-Pb isochron ages of 1.86–1.82 Ga, indicating that tin mineralization occurred in the Paleoproterozoic, nearly 1 Ga before emplacement of the Yazov granite. Tin mineralization of the ore region is probably related to ~ 1.85 Ga Chuya-Kodar tin-bearing granitic rocks that host tin deposits. These results have broad implications for understanding how critical elements, such as tin, may become enriched in rare-metal granites and how they are related to regional to global geodynamic processes.

Increasing the volume and tightening the quality standards for the water heat carrier of power units require the modernization of the chemical control system at thermal power plants (TPPs). The development of information technologies ensures the creation of automated systems of chemical-technological monitoring (SCTM) and individual devices focused on the application of reliable and inexpensive analyzers such as conductometers and pH meters with data processing using algorithms of any complexity. SCTM of feed and boiler water based on measurements of specific conductivity and pH were developed and tested under industrial conditions. Together with NPP Tekhnopribor (Moscow), a new generation analyzer Leader-APK, similar to the latest generation analyzer AMI Deltacon Power (SWAN Company), was developed. Using the analyzer in the chemical control system of a power unit of combined cycle gas turbine power plants (CCGT) allows reducing the number of automatic control devices by seven units.

Granitoids of the Uda complex are developed within the southeastern marginal part of the Siberian craton and its folded framework. Geochemical, isotope–geochemical (Nd and Sr), and geochronological (U–Pb ID–TIMS) studies of a number of massifs of this complex were carried out for the Chogar granulite block of the Dzhugdzhur–Stanovoi superterrane. It was found that the massifs were formed during the Early Jurassic (181 ± 2 Ma) under the geodynamic conditions of the active continental margin. The initial magma of these granitoids originated from a mixed source consisting of the Early Precambrian lower crust and the mantle. There is a reason to believe that the granitoids of the Uda complex in the Chogar block constitute the southwestern edge of the Uda–Murgal magmatic arc formed under subduction, which extends along the border of the Paleo-Asian Ocean and the Siberian continent.

–Anorthosites of the Olonkhuduk pluton of the Central Asian Orogenic Belt are dated at 1772 ± 1 Ma (ID TIMS U-Pb zircon method). Similar age estimate (1784 ± 10 Ma) was previously obtained for anorthosite of the Khungilingol pluton from the Ider block of the Tarbagatai terrane. These data indicate a significant time gap (70–60 Ma) between the collision that formed the Early Precambrian blocks of the Baidaric and Tarbagatai terranes in the range 1860–1850 Ma and the emplacement of the anorthosites. The termination of accretion-collision processes and consolidation of the Early Precambrian block of the Baidaric terrain are marked by the postkinematic subalkaline granites with an age of 1825 ± 5 Ma. Geochemically, the anorthosites of the Olonkhuduk and Khungilingol plutons are similar to the typical anorthosites of ancient cratons. Sm-Nd isotopic data indicate a mixed source of these anorthosites: juvenile mantle component of Paleoproterozoic age and crustal component of Neoarchean age. It can be assumed that the primary mafic magma of the anorthosites experienced a significant crustal contamination. Based on the similar geologic setting, age, and composition, the anorthosites of the Olonkhuduk and Khungilingol plutons can be ascribed to a single within-plate complex. The age values obtained for the anorthosites coincide with the estimated age of rift magmatism in the North China craton at 1.8–1.75 Ga and the emplacement time of mafic dikes swarms at 1778 ± 3 Ma (SIMS U-Pb method). Thus, the considered Early Precambrian blocks by the end of the Paleoproterozoic (about 1900–1850 Ma) could be a part of the Columbia supercontinent (Rogers and Santosh, 2002).

Granite–porphyries of the Yazovka complex occur in the northern part of the Riphean Baikal–Patom fold-thrust belt within the Tonod Uplift of the Early Precambrian basement. The geochronological (U–Pb), isotope-geochemical (Sm–Nd), and geochemical studies have shown that the rocks of this complex belong to A-type tin-bearing granites of the age of 709 ± 7 Ma. Initial magma of these granites was formed from the mixed Early Precambrian crustal and mantle source in the intraplate geodynamic setting. This tectonic event was global in nature and manifested the Late Riphean impulse of the lithospheric extension, which was associated with breakup of the supercontinent Rodinia under the influence of a mantle superplume.

Strategies to capitalize on enolate intermediates generated from stereoselective conjugate borylation to α,β-unsaturated carbonyl systems are surprisingly rare despite the ubiquity of Michael acceptors, and the potential to generate valuable scaffolds bearing multiple stereocenters. Herein, we report a mild and stereoselective copper-catalyzed conjugate borylation/Mannich cyclization reaction. This strategy is feasible with a broad range of Michael acceptors, and can be leveraged to generate versatile borylated tetrahydroquinoline scaffolds bearing three contiguous stereocenters. The synthetic potential of these complex heterocycles has been explored through a series of derivatization studies., Copper-catalyzed enantio- and diastereoselective conjugate borylation across Michael acceptors, with subsequent Mannich-type cyclization, was utilized to construct tetrahydroquinoline scaffolds containing three contiguous stereocenters.

A reductive cyclization to prepare a variety of N-heterocycles, through the use of ortho-vinylanilides, is reported. The reaction is catalyzed by an inexpensive and bench-stable iron complex and generally occurs at ambient temperature. The transformation likely proceeds through hydromagnesiation of the vinyl group, and trapping of the in situ generated benzylic anion by an intramolecular electrophile to form the heterocycle. This iron-catalyzed strategy was shown to be broadly applicable and was utilized in the synthesis of substituted indoles, oxindoles and tetrahydrobenzoazepinoindolone derivatives. Mechanistic studies indicated that the reversibility of the hydride transfer step depends on the reactivity of the tethered electrophile. The synthetic utility of our approach was further demonstrated by the formal synthesis of a reported bioactive compound and a family of natural products.

A Ni-catalyzed C–S cross-coupling using only NiI2 (0.5–2.5 mol%) and P(OiPr)3 (2.0–10.0 mol%) is reported. Using an air-stable Ni(II) precatalyst, and a cheap and commercially available ligand, a scalable and robust method was developed to cross-couple various thiophenols and styryl bromides, including some sterically encumbered thiols, an α-bromocinnamaldehyde as well as a thiolation-cyclization.

Acyl substituted triazoles are valuable scaffolds, but the direct synthesis of these moieties from terminal alkynes by copper catalysis remains unexplored. We report a robust, general, and efficient method using a simple CuI/2,2'-bipyridine catalytic system. This transformation involves a copper catalyzed azide-alkyne cycloaddition (CuAAC) followed by an intramolecular acylation onto a carbamoyl chloride. The reaction proceeds under mild conditions, tolerates several functional groups, and is readily scalable. This method represents a novel strategy towards the synthesis of complex heterocycles by a CuAAC/acylation domino process.

The rhodium-catalyzed asymmetric ring opening reaction of oxabicyclic alkenes is shown to be an efficient method for synthesizing chiral heterocycles. We demonstrate that the pairwise combination of chiral catalyst with chiral amino-acid-derived pronucleophiles results in a stereodivergent synthesis of diastereomeric hydroxyesters. A favorable conformational preference induces the subsequent lactonization of one diastereomer leading to the highly enantioselective synthesis of oxazinones.

Implementation of automatic water chemistry control at power units of thermal power stations (TPS) is hindered by the unavailability of analyzers required for monitoring certain standardized characteristics of the coolant. Important characteristics include salt content and ammonia concentration in the feedwater and salt content and phosphate concentration in the boiler water. If automatic analyzers are not available, phosphate concentration in the boiler water of drum boilers with an operating pressure above 10 MPa can be determined using conductivity measurements. In this case, the concentration of phosphates is calculated using the regression equation correlating phosphate concentration with electric conductivity of a cooled boiler water sample from the salt compartment or the equation derived by transformation of the system of equations describing the ionic equilibrium in the feedwater and the boiler water. The procedure was developed based on the results of a full-scale experiment performed at the TETs-26 cogeneration power station of PAO Mosenergo. It has been demonstrated that the correlation coefficient is 1.0 and the phosphate concentration is a function of the specific electric conductivity of a direct sample and an H-cation-treated cooled sample of water taken in the salt compartment of a drum boiler. However, for practice, the results of measurement of the specific electrical conductivity of an H-cation-treated sample are the only correct ones that enables the effect of a change in the quality of the working solution of sodium phosphate or feed water to be eliminated. Additional measurements of boiler water pH make it possible to calculate the concentration of salt components and improve the reliability of chemical control if fast upsets of the water chemistry occur. The developed calculation method for determining phosphate concentrations in boiler water using conductivity measurements was verified in a TP-87 boiler with a drum pressure of 13.8 MPa at the Ivanovo TETs-3.

The Olekma magmatic belt of the Selenga–Stanovoi Superterrane within the Central Asian mobile belt is traced for a distance of more than 700 km. As a result of U–Pb geochronological studies, it was established that granitoids of the Olekma Complex have the Paleozoic age (355 ± 2 and 358 ± 2 Ma) in the eastern and central part of the belt, whereas consolidation of granitoids with a similar composition in the western segment occurred in the Early Mesozoic (237 ± 1 Ma). The formation of Mesozoic granitoids of the Olekma Complex occurred under the conditions of lithospheric extension, whereas Late Paleozoic granitoids were most likely formed during the collision of the Selenga–Stanovoi Superterrane and structures of the Baikal mountain area.

The utilization of the Bpin group as a pronucleophile to facilitate the assembly of cyclic carbamates has been achieved. This one-pot process involves an initial copper-catalyzed borylation, a subsequent C-B bond oxidation to generate the reactive alcohol intermediate, and a cyclization. We report the use of this efficient, scalable, and simple method toward the synthesis of a wide range of benzoxazinone scaffolds, including enantioselective results. Subsequent transformations into useful scaffolds showcase the utility of this strategy.

THE PURPOSE. To consider issues related to the study of methods for determining the sources of violations of the quality of electrical energy in power supply systems, in particular consumers which create rapid voltage changes or voltage fluctuations that create rapid changes in the luminous flux in electric lighting installations. Show that electrical receivers with a sharply variable operating mode are sources of fluctuations in the consumed current and voltage in the electrical network of power supply systems, which in turn manifests itself in the form of unacceptable values of one of the indicators of the quality of electricity - flicker, defined as the subjective perception of fluctuations in the luminous flux of lighting devices. To study the possibilities of determining the places of occurrence of significant voltage fluctuations without the use of expensive and complex instruments for measuring flicker values in the electrical network. To develop a simplified method for determining the locations of electricity consumers that negatively affect the operation of electric lighting systems and, ultimately, the vision of personnel. Conduct a check on a computer model of a simplified method for determining the places of occurrence of voltage fluctuations that are inadmissible in their magnitude, which are expressed in the appearance of significant doses of flicker that exceed the standard values.METHODS. Solving the problem, a computer model was used, created in the Simulink extension package of the Matlab scientific and technical calculation system.RESULTS. The article describes the relevance of the problem, discusses the quality of electricity in power supply systems. It has been shown using experimental data that in electrical networks there is an excess of the standard values of flicker doses. The possibility of using interharmonic components of the mains voltage to determine the sources of unacceptable doses of flicker is considered. A simplified method for finding flicker sources based on obtaining the values of the derivatives of currents at various points of the electrical network is presented. Computer simulation of an electrical network diagram with electrical receivers, which have both calm and sharply variable nature of work, has been performed. It is shown that the use of the values of the derivatives of the current at various points of the electrical network makes it possible to identify the sources of the occurrence of unacceptable doses of flicker.CONCLUSION. The occurrence of significant rapid voltage changes in the electrical network negatively affects vision, which is inevitably accompanied by increased personnel fatigue and can lead to industrial injuries. The results obtained by the authors of the article show that it is possible to use it to determine the places of occurrence of large voltage fluctuations, which are manifested in unacceptable doses of flicker of the derivatives of currents. It should be taken into account when conducting surveys of power supply systems in order to use fairly simple hardware to identify sources of disturbance in the quality of electrical energy.

The oxindole scaffold is a privileged structural motif that is found in a variety of bioactive targets and natural products. Moreover, derivatives of the oxindole structure are widely present in a number of biologically relevant compounds and are key intermediates in the synthesis of diverse natural products and pharmaceuticals. Therefore, novel methods to obtain oxindoles remain of high priority in synthetic organic chemistry.Over the past several decades, novel transition-metal-catalyzed methodologies have been applied toward the synthesis of a variety of heterocycles. A detailed mechanistic understanding facilitates the disruption of traditional catalytic pathways to access useful synthetic intermediates. The strategies employed have generally revolved around the generation of high-energy organometallic intermediates, which undergo cyclization reactions through domino processes. Domino cyclization methodologies are therefore attractive, as they allow facile access to functionalized oxindoles containing all-carbon quaternary centers or tetrasubstituted olefins with high chemo- and stereoselectivities. Furthermore, these developed synthetic strategies can often be easily applied in the syntheses of other related scaffolds.In this Account, we discuss the three unique strategies that our group has leveraged for the synthesis of valuable oxindole scaffolds. The first section in this Account outlines the use of an initial oxidative addition to a C(sp

The Elikanskiy granite–gneiss swell represents a structure, similar to Late Mesozoic Cordilleran-type metamorphic core complexes allocated within the Eravninskiy terrane of the Yenisei-Transbaikal tectonic collage, the Mongolo-Okhotskiy orogenic belt and a northern part of the Argun–Idermeg superterrane of the Central Asian orogenic belt. The main elements of a geological structure of the Elikanskiy metamorphic core complex are the detachment zone, core and upper nappe. The detachment zone separating a core from the upper nappe is represented by a thick zone of blastomylonites and a zone of chlorite breccias. That zone was formed under the conditions of tangential stress and led to the exhumation and structural and metamorphic transformations of magmatic rocks of the Bukhtochinskiy Complex and metamorphic rocks of the Upper Olekma Complex, which compose the core of the considered structure. The upper nappe consists of Jurassic and Cretaceous stratified rocks of the Kyker–Akimin and Usuglinskiy basin and the Early Paleozoic–Mesozoic volcanoplutonic complexes in its southeastern framing. The Elikanskiy metamorphic core complex is a part of a huge belt of metamorphic core complexes which is traced along the northern border of the Mongolo-Okhotskiy orogenic belt on distance about 2000 km. The formation of the Elikanskiy metamorphic core complex as well as other similar complexes in the eastern part of the Central Asian orogenic belt is connected with collapse of the Late Mesozoic orogen which has resulted from the accretionary and collision events connected with closing of the Mongolo-Okhotskiy paleoocean basin and respectively formation of the Mongolo-Okhotskiy orogenic belt.

The change-over to the European standards for the quality of water coolant in power units of thermal and nuclear power stations makes the requirements for the feedwater quality stricter and brings about problems in the measurement of pH. The conventional calibration of a pH-meter against buffer solutions does not yield the measurement accuracy during measurements in infinitely diluted water solutions with electrical conductivity below 0.3 μS/cm. Reliability and validity of pH measurements can be improved by using the readings of automatic conductivity meters and calibration of analyzer in a superpure medium. The first method is implemented in foreign-made instruments, such as FAM Deltacon pH and AMI Deltacon Power. The second method has not yet been developed and is waiting for its implementation in practice. The investigation of the possibility for implementation of these methods using domestic equipment was carried out in the laboratory at the ion-exchange membrane test facility with metering ammonia or carbonic acid solution into deeply demineralized water and was verified under actual operating conditions at the Petrozavodsk Cogeneration Power Station (TETs) and the Kostroma District Power Station (GRES). This investigation resulted in the design of a prototype of a Lider-APK industrial analyzer intended for measurement of pH and concentration of impurities (such as ammonia, sodium, or chlorides) in condensate type waters in the range of pH = 6.0–10.0, and the development of a calibration procedure of industrial bench test pH-meters using ammonia or carbonic acid solutions. The Lider-APK analyzer outperforms its import equivalents and can be used in the automatic chemical monitoring at thermal power stations (TPS). A procedure for calibration of pH-meters in ultradiluted solutions has been first developed and should be verified at industrial facilities. The results of investigation suggest that both methods can improve the reliability of pH measurements in a superpure water coolant using automatic analyzers.

The Dotulur alkalic granite and Usugli Depression volcanics (West Stanovoi Superterrane of the Central Asia Fold Belt) have been dated by the U–Pb method, and their geochemistry has been analyzed. The geochemistry of the rocks suggests their intraplate nature. The alkalic granite and volcanics have similar ages of 142 ± 1 Ma and 138 ± 3 Ma, respectively. Considering the Usugli Depression structural position as an upper fault slice of the Elikan metamorphic core, the obtained dates allow the formation of the mentioned core and, accordingly, the collapse of central part of the Mongol–Okhotsk orogeny to have occurred not prior to 140 Ma.

The geochemistry, geochronology, and isotope geochemical systematics (Nd, Sr, Hf, and Pb) of the granitoids of the Pozdnestanovoy complex of the Dzhugdzhur–Stanovoy superterrane of the Central Asia fold belt were investigated. It was shown that their age is Mesozoic (142–138 Ma) rather than Early Precambrian, as was previously supposed. The main sources of parental melts for these granitoids were the Neoarchean and Paleoproterozoic rocks of the lower continental crust of the Dzhugdzhur–Stanovoy superterrane and the rocks of the Late Paleozoic–Early Mesozoic continental crust of the Amur microplate. They were formed at depths of >40 km and temperatures of 700–800°C, most likely through the melting of mafic feldspar granulites under the conditions of aqueous fluid infiltration without any significant contribution from a juvenile heat source. The granitoids of the Pozdnestanovoy complex were emplaced during the closure of the eastern segment of the Mongolia–Okhotsk Ocean owing to the collision of the Siberian and Sino-Korean continents.

Discriminant analysis was performed for representative sets of igneous rocks with adakitic geochemical signatures (granitoids of Archean tonalite–trondhjemite–granodiorite suites, island-arc adakites, and adakites and adakitic granitoids of collisional to postcollisional geodynamic settings). It was shown that the granitoids of Archean tonalite–trondhjemite–granodiorite suites are significantly different from islandarc adakites, as well as from collisional to postcollisional adakites and adakitic granitoids. The following discriminant function was proposed for the geodynamic classification of island arc and collisional-postcollisional adakites and adakitic granitoids on the basis of chemical composition: DF3 =–1.69324TiO2–0.25537Al2O3–0.21269FeO* + 0.06076MgO–0.09796CaO + 0.47377Na2O + 0.29270K2O + 3.57821P2O5 + 0.00431Rb + 0.00036Sr + 0.03119Y + 0.00006Zr + 0.01088Nb–0.00048Ba + 0.01366La + 0.0004Ce + 0.02319Nd–0.18584Sm + 1.29135Eu–0.62229Gd + 0.3819Dy + 2.06583Er–2.62769Yb + 1.6464.

Biotite plagiogranite intruding sediments of the Kodar Sub-Group of the Udokan Group that have both undergone amphibolite grade alterations has been dated by the U–Pb ID TIMS technique using zircon to 2105 ± 6 Ma. This age estimate to a first approximation corresponds to the younger age limit of deposition of the siliciclastics in the lower section of the Udokan Group.

In late May–early June 2017, two international science and technology conferences on problems of water chemistry and chemistry monitoring at thermal and nuclear power plants were held. The participants of both the first conference held at OAO VTI and the second conference that took place at NITI formulated the problems of the development of the regulatory base and implementation of promising water treatment technologies and outlined the ways of improving the water chemistry and chemistry monitoring at TPPs and NPPs for the near future. It was pointed out that the new amine-containing VTIAMIN agent developed by OAO VTI had been successfully tested on the power-generating units equipped with steam–gas plants to establish the minimum excess of the film-forming amine in the power-generating unit circuit that ensures the protection of the metal as 5–10 μg/dm3. A flow-injection technique for the analysis of trace concentrations of chlorides was proposed; the technique applied to the condensate of the 1000-MW steam turbine of the NPP power-generating unit yields the results comparable with the results obtained by the ion chromatography and the potentiometric method using the solver electrode. The participants of the conferences were demonstrated new Russian instruments to analyze the water media at the TPPs and NPPs, including the total organic carbon analyzer and the analyzer of mineral impurities in the condensate and feed water, that won a gold medal at the 45th International Exhibition of Inventions held in Geneva this April.

The U–Pb (ID TIMS) geochronological studies of single zircon grains and their fragments have made it possible to establish that rare-metal alkaline granites of the Katugin massif (2055 ± 7‒2066 ± 6 Ma) underwent high-temperature transformations at age levels of ~1921 ± 5 and 1876 ± 7 Ma.

Damageability of heat transfer surfaces of waste heat recovery steam generators (HRSG) of combined- cycle plants (CCP) can be reduced due to an increase in the quality of make-up and feed water, the use of phosphate-alkaline or amino compound water chemistry (WC), and improved chemical quality control of the heat carrier and make-up water preparation techniques. Temporary quality standards for the heat medium developed by the All-Russia Thermal Engineering institute (VTI) for CCP power units are presented in comparison with the IAPWS standards; preferences for the choice of a WC type for some power units commissioned in Russia in the first decade of this century are shown; and operational data on the quality of feed, boiler water, and steam for two large CCP-450 and CCP-425 power units are given. The state and prospects for the development of chemical-technological monitoring systems and CCP water treatment plants are noted. Estimability of some CCP diagnostic parameters by measuring specific electric conductivity and pH is shown. An extensive bibliography on this topic is given.

We studied the petrography, mineralogy, and geochemistry of the Paleoproterozoic (2.06 Ga) granites of the Katugin massif (Stanovoy suture zone), which hosts the combined rare-metal Katugin deposit. Three groups of granites were distinguished: (1) biotite (Bt) and biotite–riebeckite (Bt–Rbk) granites of the western block of the massif; (2) biotite–arfvedsonite (Bt–Arf) granites of the eastern block; and (3) arfvedsonite (Arf), aegirine–arfvedsonite (Aeg–Arf), and aegirine (Aeg) granites of the eastern block. The Bt and Bt–Rbk granites of the first group are mainly metaluminous and peraluminous rocks with rather high CaO contents and the minimum F contents among the granites described here. It was suggested that the granites of this group could be derived from a source dominated by crustal rocks with a small addition of mantle materials. These granites probably crystallized from a metaluminous–peraluminous melt with elevated CaO and moderate F contents. Melts of such compositions are least favorable for the crystallization of ore minerals. The Bt–Arf granites of the second group are mainly peralkaline and show high contents of CaO and Y and low contents of Na2O and F. A mixed mantle–crust source was proposed for the Bt–Arf granites. The initial melt of the Bt–Arf granites could have a peralkaline composition with elevated CaO content and moderate to high F content. The Arf, Aeg–Arf, and Aeg granites of the third group are enriched in ore mineral and were classified as peralkaline granites with very low CaO contents, elevated Na2O and F contents, and usually very high contents of Zr, Hf, Nb, and Ta. Based on the geochemical and isotopic data, it was supposed that the source of the granites of the third group could be derivatives of basaltic magmas produced in an OIB-type source with a minor addition of crustal material to the magma generation zone. It was suggested that the primary melt of this granite group could be a peralkaline CaO-poor and F-rich silicic melt, which is most favorable for the crystallization of ore minerals. Based on the analysis of the geochemical characteristics of the three granite groups and their relationships within the Katugin massif, a qualitative model of its formation was proposed. According to this model, the Bt and Bt–Rbk granites of the western block crystallized first, followed by the Bt–Arf granites of the eastern block and, eventually, the Arf, Aeg–Arf, and Aeg granites enriched in ore minerals.

A rhodium-Josiphos(L*) catalyzed enantioselective intramolecular hydroarylation reaction is described. The reductive cyclization of o-bromoaniline-derived acrylamides provides convenient access to 3,3-disubstituted oxindoles in good yields and with excellent enantioselectivity across a range of substrates. We propose that the key cyclization proceeds via a rhodium(III) intermediate. Overall, this method represents an unusual mode of reactivity for rhodium catalysis and is complementary to palladium(0)-catalyzed α-arylation protocols.

Based on the results of Sm–Nd isotopic geochemical and U–Th–Pb geochronological LA–ICP–MS studies, it has been established that the formation of metamorphic rock protoliths of the Stanovoi Complex in the western Dzhugdzhur–Stanovoi Superterrane of the Central Asian Foldbelt took place over the following time spans: 2750–2860 Ma (Ilikan Group of the Ilikan Zone), 1890–1910 Ma (Bryanta Group of the Bryanta Zone), and ~2.0 Ga (Kupuri and Zeya groups of the Kupuri and Zeya zones, respectively). It has been shown that the western part of the Dzhugdzhur–Stanovoi Superterrane was formed ~1.9 Ga ago, as a result of collision of the Neoarchean Ilikan Terrane, the Paleoproterozoic island arc, and the Paleoproterozoic Kupuri–Zeya Terrane. The data make it possible to consider the Kurul’ta, and Zverevo blocks of the Stanovoi Structural Suture and the Ilikan Terrane of the Dzhugdzhur–Stanovoi Superterrane of the Central Asian Foldbelt as constituents of a common terrane.

The necessity of developing a new industry-specific standard of the heat carrier quality for the operating, newly commissioned, and prospective power-generating units of the thermal power plants is substantiated. The need of extending the scope of the automatic chemical monitoring and the possibility of indirect measurements of some basic standardized and diagnostic indices of the water chemistry using the specific conductance are shown. Investigations proved the possibility of automatic chemical monitoring of the phosphating of the drum boilers and quantitative control of potentially acidic impurities in the feed water in oncethrough boilers. The normative STO NP INVEL document developed at OAO VTI in 2009 is proposed as the basis for alterations and amendments. A new index, the total organic carbon, is introduced into this document. The standardized value of this index in the drum boiler feed water and steam is 100 μg/dm3. According to the above normative document, the scope of the chemical monitoring should be extended by measurements of the specific conductance of the direct and H-cation samples of both the feed and the boiler water. The content of chlorides should also be standardized. For the first time, normative restrictions are suggested on amine-containing water chemistry of the power-generating units with the combined cycle gas turbines. Flowcharts are proposed for pretreatment of the make-up water on the basis of low-mineralized natural waters with high organic substance contents, which reduces the oxidizability by 70–80%.

The need to increase the amount of automatic chemical control is pointed out, especially by measuring the conductivity of cooled probes, including direct and H-cation probes. These studies demonstrate the possibility of automatic chemical control of the phosphate regime in drum boilers and quantitative monitoring of the amount of potentially acid substances, i.e., impurities in the feed water for flow-through boilers. It is proposed that the 2009 standards document STO by the firm NP “INVEL” should be taken as the basis with a number of changes and additions. For the first time, a number of standard limits for amine-containing water-chemical regulation of the steam-gas generating units are recommended. The following limits are proposed for the introduction of an amine water-chemical regime in units without copper-containing alloys: for the turbine condensate the conductivity of an H-cation sample should be less than 1.0 μS/cm and the amount of dissolved oxygen should be less than 20 μg/dm3; the feed water conductivity of an H-cation sample should be less than 1.0 μS/cm and the pH = 8.9 – 9.5; the amount of dissolved oxygen after the deaerator should be less than 10 μg/dm3 and the amount of film-forming amines greater than 10 μg/dm3. Schemes for preliminary treatment of low-mineral natural water with elevated contents of organic materials are proposed which reduce the acidity of the water by 70 – 80%.

We report here a proof of concept for the cleavage of unstrained remote Csp3–Csp3 bonds at room temperature assisted by a directing group, opening up new possibilities to use aliphatic carboxylic acids as suitable alkenyl coupling partners. This strategy involves the Pd-mediated Csp3–H activation directed by a tethered 8-aminoquinoline group, followed by a concerted asynchronous carbene insertion into the Pd–C bond, and an unexpected β-carbon-carbon bond splitting. The insertion of a coupling partner into a Pd–C bond is a novel route to promote C–C bond cleavage, which, in contrast to most common methodologies, does not rely on the use of strained carbocycles.

The electrochemical reduction of CO2 into renewable chemical products such as formic acid is an important and challenging goal. Traditional Pd catalysts suffer from CO poisoning, which leads to current density decay and short operating lifetimes. Here we explored the ability to control Pd nanoparticle surface morphology to amplify catalytic activity and increase stability in the electroreduction of CO2 to formate. Through computational studies we have elucidated trends in intermediate binding which govern the selectivity and catalytic activity. We then rationally synthesized Pd nanoparticles having an abundance of high-index surfaces to maximize electrocatalytic performance. This catalyst displays a record current density of 22 mA/cm2 at a low overpotential of −0.2 V with a Faradaic efficiency of 97%, outperforming all previous Pd catalysts in formate electrosynthesis. The findings presented in this work provide rational design principles which highlight morphological control of high-index surfaces for th...

The Gilyui Complex includes sedimentary and volcanic rocks metamorphosed to amphibolite and epidote–amphibolite facies, which constitute blocks confined to the main structural sutures of the Dzhugdzhur–Stanovoi superterrane in the Central Asian fold belt. In recent stratigraphic scales, they are considered as being Neoarchean in age with Nd model age values of 1.5–3.0 Ga. The youngest detrital zircons from metamorphosed mudstone of the Gilyui Complex yield a date of 285 ± 4 Ma, which determines the lower age limit for the formation of its protolith. The age of crystallization of rhyolites from the Gilyui Complex is determined to be 231 ± 4 Ma. If the rhyolites form volcanic flow units or sills, the Gilyui Complex is approximately 230 Ma or 231 ± 4 to 285 ± 4 Ma old, respectively.

The results of Sm–Nb isotopic–geochemical studies of metasedimentary and metavolcanic rocks of the Dzheltulak Group of the central part of the Dzheltulak suture, as well as geochronological U–Th–Pb (LA ICP MS) studies of detrital zircons from metasedimentary rocks, which are considered as Paleoproterozoic in current stratigraphic schemes, are presented. The age of the youngest zircons is 170–190 Ma, whereas the age of the last stage of regional metamorphism is 140–150 Ma. Thus, the Dzheltulak Group hosts metasedimentary rocks, the age of the protolith of which ranges from 140–150 to 170–190 Ma. The detrital zircons derived from intrusive and metamorphic rocks of the Selenga–Stanovoi and Dzhugdzhur–Stanovoi superterranes.

Arguments in favor of magmatic or metasomatic genesis of the Katugin rare-metal ore deposit are discussed. The geological and mineralogical features of the deposit confirm its magmatic origin: (1) the shape of the ore-bearing massif and location of various types of granites (biotite, biotite–amphibole, amphibole, and amphibole–aegirine); (2) the geochemical properties of the massif rocks corresponding to A type granite (high alkali content (up to 12.3% Na2O + K2O), extremely high FeO/MgO ratio (f = 0.96–1.00), very high content of the most incoherent elements (Rb, Li, Y, Zr, Hf, Ta, Nb, Th, U, Zn, Ga, and REE) and F, and low concentrations of Ca, Mg, Al, P, Ba, and Sr); (3) Fe–F-rich rock-forming minerals; (4) no previously proposed metasomatic zoning and regular replacement of rock-forming minerals corresponding to infiltration fronts of metasomatism. The similar ages of the barren (2066 ± 6 Ma) and ore-bearing (2055 ± 7 Ma) granites along with the features of the ore mineralization speak in favor of the origin of the ore at the magmatic stage of the massif’s evolution. The nature of the ore occurrence and the relationships between the ore minerals support their crystallization from F-rich aluminosilicate melt and also under melt liquation into aluminosilicate and fluoride (and/or aluminofluoride) fractions.