141 research outputs found

    Reaction of acylisocyanates with unsaturated ethers

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    1. The trifluoroacetyl and trichloroacetyl isocyanates react with allyl vinyl and vinyl phenyl ethers to give linear adducts of general formula R1CONHCOCH=CHOR2. Benzoyl isocyanate reacts in a similar manner with allyl vinyl ether. 2. The trifluoroacetyl and trichloroacetyl isocyanates react with p-tolyl vinyl sulfide and p-bromophenyl vinyl sulfide, while benzoyl isocyanate reacts with phenyl vinyl ether, to give the corresponding substituted dihydro -1,3 -oxazin-4-ones. 3. An NMR study of the reactions of the geometric isomers of butenyl ethyl ether with trichloroacetyl isocyanate confirmed that fact that the formation of the linear isomers proceeds via intermediate 4- and 6-membered cyclic compounds. © 1975 Plenum Publishing Corporation

    Carbon Sequestration Dynamics in Urban-Adjacent Forests: A 50-Year Analysis

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    Achieving carbon neutrality is crucial for urban ecosystems. Forests growing near cities largely determine the state of the environment in urban areas. The aim of the present research is to assess the carbon productivity dynamics in forests near Krasnoyarsk (a large industrial center) over a 50-year period in terms of carbon sequestration and conservation. The study was based on forest inventory conducted in Karaul'noe Forestry in 1972, 1982, and 2002 and forest inventory covering six forest compartments in 2022. The forest covers 3980 ha and consists of 52 forest compartments. The analysis was based on the assessment of carbon productivity dynamics and followed four levels of principles: forestry, structure, forest compartment, and forest stand. The research was based on forest fund dynamics, analyzing methods, long-term forest inventory, assessing carbon stock, and growing stock dynamics. Pine is the dominant forest-forming species that absorbs the most carbon in the study area. Pine is long-lived, covers a vast area, and has the highest carbon sequestration potential. At the forest structure level, the predominant carbon pools are mid-late successional and late successional stands dominated by pine, birch, and aspen. Forest compartment-level analysis revealed three trends in carbon sequestration: carbon balance, a decrease in carbon sequestration, and an increase in carbon sequestration. Notably, the prevailing trend is determined by changes in carbon sequestration by dominant forest-forming species (pine). Forest stand-level analysis showed that stands have become more and more uneven-aged. About 65% of total carbon stock is concentrated in mid successional, mid-late successional and late-successional stands, and 35% in young stands. The carbon sequestration rate decreases in forests with age. However, pine forests increase biological productivity and continue to successfully sequester carbon. Deciduous forests have lost their carbon sequestration potential, and the area they occupy is currently decreasing in the study area. The development of the young generation in pine stands suggests that the carbon sequestration potential in forests growing near the city will not decrease and may even increase due to climate change. Doi: 10.28991/CEJ-2023-09-09-08 Full Text: PD

    Detailed Analysis of Early to Late-Time Spectra of Supernova 1993J

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    We present a detailed study of line structure in early to late-time spectra of Supernova (SN) 1993J. Spectra during the nebular phase, but within the first two years after explosion, exhibit small-scale structure in the emission lines of some species, notably oxygen and magnesium, showing that the ejecta of SN 1993J are clumpy. On the other hand, a lack of structure in emission lines of calcium implies that the source of calcium emission is uniformly distributed throughout the ejecta. These results are interpreted as evidence that oxygen emission originates in clumpy, newly synthesized material, while calcium emission arises from material pre-existing in the atmosphere of the progenitor. Spectra spanning the range 433-2454 days after the explosion show box-like profiles for the emission lines, clearly indicating circumstellar interaction in a roughly spherical shell. This is interpreted within the Chevalier & Fransson (1994) model for SNe interacting with mass lost during prior stellar winds. At very late times, the emission lines have a two-horned profile, implying the formation of a somewhat flattened or disk-like structure that is a significant source of emission. The very high signal-to-noise ratio spectra are used to demonstrate the potential significance of misinterpretation of telluric absorption lines in the spectra of bright SNe.Comment: 34 pages, 16 figures, AASTeX V5.0. Accepted for publication in A

    Food labelling and food-induced anaphylaxis in children. Where are the intersection points?

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    Anaphylaxis is an acute life-threatening condition affecting several body systems. It might have a rapid onset and lead to a lethal outcome. The major provoking factors for the development of anaphylactic reactions in childhood are food allergens. High hypersensitivity to one food allergen can make it difficult for a family to find a substitution for an allergenic product. Food-induced anaphylactic reaction to quite a number of food allergens is a serious problem for both the physician and the family of an allergic child necessitating organization of appropriate and safe nutrition. In real life, the standard recommendation for the patient – to strictly follow the rules of the elimination diet with exclusion of the causative allergen and all cross-reactive allergens – often becomes unrealizable. There is a serious risk of developing new allergic reactions due to accidental intake of the triggering allergens because of incorrect food labelling by manufacturers. The objective of the work is to present a clinical case report that demonstrates the importance of performing allergy component testing (ImmunoCAP ISAC-112,) for identification of the full spectrum of allergens with subsequent assessment of allergenic molecules as triggering allergens and shows serious difficulties in the elaboration of recommendations on a personalised diet that should be adequate and safe for a child with a history of recurrent episodes of food-induced anaphylaxis.Анафилаксия – острое жизнеугрожающее состояние, затрагивающее несколько систем организма, которое может развиться мгновенно и привести к фатальному исходу. Основными провоцирующими факторами развития анафилактических реакций в детском возрасте являются пищевые аллергены. При выраженной гиперчувствительности к одному пищевому аллергену возникают сложности для семьи в плане замены виновного продукта. Наличие же пищевой анафилаксии к большому числу пищевых аллергенов – это серьезная проблема для врача и семьи пациента по организации полноценного и безопасного питания ребенка. В реальной жизни обязательная рекомендация для пациента – придерживаться жестких правил элиминационной диеты с исключением причинно-значимого аллергена и всех перекрестных с ним аллергенов – зачастую становится просто невыполнимой. Серьезный риск возникновения новых аллергических реакций существует при случайном попадании в организм аллергенов-триггеров из-за неоднозначности маркировки пищевых продуктов при изготовлении этикеток на продуктах питания. Цель работы: представить клинический случай, демонстрирующий важность проведения компонентного аллергологического обследования (ISAC-112, ImmunoCAP) для выявления полного спектра аллергенов с дальнейшей оценкой аллергенных молекул как аллергенов-триггеров и раскрывающий серьезные трудности в разработке рекомендаций по индивидуальной лечебной диете, которая должна быть полноценной и безопасной для ребенка с повторными эпизодами пищевой анафилаксии в анамнезе

    Scientific support of small fruit growing in Russia and prospects for its development

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    It is possible to achieve the target indices of the Russian Doctrine of Food Security (self-sufficiency in fruits and berries should be at least 60 %) by combining the competencies of science and business. At present, hundreds of varieties of small fruit crops are included in the State Register of Breeding Achievements Admitted for Use. Domestic breeders have obtained substantial results; the share of their assortment is 79–100 %. Federal Research Center of Horticulture (Moscow) (101 pcs.), Federal Altai Research Center of Agrobiotechnology (Barnaul) (85 pcs.), Michurin Federal Research Center (Michurinsk) (42 pcs.) are the leaders in the number of created hybrids and varieties. Over the past five years, 133 new breeding achievements of traditional small fruit crops have been submitted to the State variety testing, the originators of which are research institutions, private companies and individuals. The creation of modern seed-breeding (nursery-breeding) centers (SBC) on the basis of leading specialized research institutions is expected to be the solution to the problems of modern breeding and nursery breeding and to give impetus to the development of domestic small fruit growing. The research programs of the SBC involve an integrated approach that combines the knowledge and capabilities of researchers from different disciplines, the concentration of a complex analytical instrument base in the Centers of collective use, the using of biotechnological and molecular genetic research, along with traditional methods of breeding. An analysis of the achievements in small fruit growing in research institutions under the jurisdiction of the Ministry of Science and Higher Education of the Russian Federation revealed a huge scientific potential (genetic collections, hybrid funds) for creating competitive commercial varieties and technologies for their cultivation by establishing plantations with certified planting material in accordance with international requirements. Information from literary sources indicates that one of the main criteria for the value of varieties is resistance to harmful viral diseases. The cultivation of such varieties will reduce the cost of producing planting material for small fruit crops of the highest quality categories. In the near future, the most relevant areas for the breeding of small fruit crops will be: breeding for resistance to the most harmful viruses, winter hardiness, increased transportability and long-term post-harvest storage of fruits, suitability for mechanized cultivation, high content of biologically active substances

    Synthesis of Pyrimidine Conjugates with 4-(6-Amino-hexanoyl)-7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4] benzoxazine and Evaluation of Their Antiviral Activity

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    A series of pyrimidine conjugates containing a fragment of racemic 7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine and its (S)-enantiomer attached via a 6-aminohexanoyl fragment were synthesized by the reaction of nucleophilic substitution of chlorine in various chloropyrimidines. The structures of the synthesized compounds were confirmed by1H,19F, and 13 C NMR spectral data. Enantiomeric purity of optically active derivatives was confirmed by chiral HPLC. Antiviral evaluation of the synthesized compounds has shown that the replacement of purine with a pyrimidine fragment leads to a decrease in the anti-herpesvirus activity compared to the lead compound, purine conjugate. The studied compounds did not exhibit significant activity against influenza A (H1N1) virus. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 19-13-00231-PFunding: This research was funded by the Russian Science Foundation, grant number 19-13-00231-P

    Piecewise polynomial approximation of probability density functions with application to uncertainty quantification for stochastic PDEs

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    The probability density function (PDF) associated with a given set of samples is approximated by a piecewise-linear polynomial constructed with respect to a binning of the sample space. The kernel functions are a compactly supported basis for the space of such polynomials, i.e. finite element hat functions, that are centered at the bin nodes rather than at the samples, as is the case for the standard kernel density estimation approach. This feature naturally provides an approximation that is scalable with respect to the sample size. On the other hand, unlike other strategies that use a finite element approach, the proposed approximation does not require the solution of a linear system. In addition, a simple rule that relates the bin size to the sample size eliminates the need for bandwidth selection procedures. The proposed density estimator has unitary integral, does not require a constraint to enforce positivity, and is consistent. The proposed approach is validated through numerical examples in which samples are drawn from known PDFs. The approach is also used to determine approximations of (unknown) PDFs associated with outputs of interest that depend on the solution of a stochastic partial differential equation
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