bluuebunny/crossref_metadata_2025 huggingface dataset:
Zebrafish as a promising model for investigating biological activities of ginseng species—a review
Authors: Yu Meijie , Wang Lulu , Luo Haiqing , Yang Bo , Li Li , Dong Jiaxin , Meng Xianghe , Sun Mengmeng , He Min
Published: February 2024

Plants of the ginseng species have a long history with broad traditional applications, as these are recognized as precious tonic herbal medicines since ancient times. More and more multiple chemical constituents and pharmacological activities have been confirmed and discovered recently. Owing to its advantages, such as intuitiveness, cheap, easy to operate, and high-throughput screening, zebrafish has become a very popular model at present. Recently, more and more toxicity tests, bio-activity evaluation, and mechanism studies have been achieved via zebrafish models, many of which were focused on the nature of products, including monomers, extracts, and formulas from ginseng species. This review summarizes the recent pharmacological studies achieved by embryos, larvae, and adult zebrafish. This review provides a theoretical basis for the rational use of ginseng species plants, thus providing guidance for a better rational utilization and the potential innovative product development of ginseng species plants.
Los memes dentro de las luchas de violencia de género: limitantes del humor y la reflexión
Authors: Angie Carolina Cicua Castro  , Paula Francisca Calderón López
Published: February 2024

El análisis de los memes ya no se centra únicamente en la comprensión del formato, o de su capacidad de masificación, en la actualidad se está adquiriendo importancia al contenido y al discurso que este transmite. Dentro de los movimientos sociales, estas piezas han sido de carácter relevante en el paso de la lucha de las calles a las redes que se vio acelerado por la pandemia. Entendiendo esto, surge la necesidad de analizar el discurso que manejan los memes dentro de la lucha de género y marcar el límite entre el humor y la discriminación.
Czym jest dzieciństwo? Pedagogiczne podejście do badań na dzieciństwem
Authors:   Uniwersytet im. Adama Mickiewicza w Poznaniu, Kiszka Monika
Published: February 2024

Interest in children and childhood has changed through the years. The changes were involved in theoretical ways of defining children and youth. Nowadays, these categories are intangible. It is evident that through ages, adults have changed how they treat children, think about childhood, and plan and research children and youth. The change from traditional to modern categories must be the clue to understanding childhood studies. The main reason for writing this paper was to discuss childhood research and studies. At the beginning are presented the historical contexts of the childhood research paradigm. In addition, basic ideas are shown about the modern formation of childhood studies. Moreover, the clue of this paper below is to show a paradigm change: a transition from traditional childhood to a modern one called childhood. The article is based on pedagogy and social studies literature. Also, it is a theoretical discussion about child and childhood studies.
Język eksponatów matematycznych jako kontekst budowania mentalnych ścieżek edukacyjnych zwiedzających centra nauki
Authors:   Uniwersytet Warmińsko-Mazurski w Olsztynie, Bojarska-Sokołowska Agnieszka
Published: February 2024

Mathematical exhibits are an element of mathematical and didactic culture. The text below analyzes the elements of the narrative language of exhibits/exhibitions, which may be the carrier of specific meanings created by visitors to science centres. The analyzes undertaken in the text made it possible to indicate the categories of the language of commands and questions contained in these narratives. They are a cognitive context for creating mathematical cultural meanings among visitors to the centres. The study was carried out in two science centers in Poland, using a qualitative strategy, analyzing documents. The results showed quite a rich educational potential of mathematical exhibits. The language of the exhibits revealed the possibility of extensive cognitive support in the mathematical development of people visiting the centres. Forming beliefs consistent with current scientific knowledge about math cognition and learning.
Wartości w wieku przedszkolnym. Czyli o rzeczach ważnych dla dzieci
Authors:   Uniwersytet w Białymstoku, Laskowska Agnieszka
Published: February 2024

Values in everyone’s life are an integral part of their existence. They guide their actions. They influence the decisions made. They help interpret their own behaviors and actions of others. Preschool age is a period when moral development begins, there are things that are more or less important to the child. It is therefore worth discovering what is important to preschool children. In order to learn about the values that are important to preschool children, a study was conducted involving 70 six-year-old children attending selected Bialystok kindergartens and preschool departments. The method used in the study was the analysis of work products and the tool was drawing analysis. The study took place during the children’s stay at the facility. The data obtained allowed to answer the research problem: What values do six-year-old children consider important in their lives? The most important value for the children surveyed is family. Then play, toys and God as the creator of the world. The empirical data obtained can be a valuable source of information, allowing to adjust the education and upbringing process in such a way as to respond to the child’s nearest area of development.
Ekaterinburg at the Turn of the 20th Century: Traditions and Innovations in the Organisation of Urban Space
Authors:   Institute of History and Archaeology UB RAS, Ekaterinburg, Yakhno Olga N.
Published: February 2024

This article studies the transformations of the urban space of Ekaterinburg in the conditions of socioeconomic changes in the late nineteenth — early twentieth centuries, associated with the development of transport and industrial infrastructure, population growth, and transformation into a “model capitalist city”. Changes in the activities of citizens in the economic, sociopolitical, cultural, educational, and leisure spheres required appropriate spatial and physical design. The article identifies the most important territorial zones of concentration (clusters) of buildings and infrastructure elements that began to set the specialisation of specific parts of the city. One can distinguish a commercial and financial cluster in the western part, a medical cluster in the northwestern part, and a leisure cluster in the eastern part of the city. The key social systems — religious and educational — tended to encompass the whole city. It is also noted that during the residential development, there was no strict separation of rich and poor districts even in the city centre. The specialisation of different parts of the city centre formed during the period under consideration, continued to influence the development of the planning structure of Ekaterinburg-Sverdlovsk, consolidating a peculiar division between the financial and commercial right-bank and cultural and social left-bank parts of the city. There was little economic development of the eastern border of Ekaterinburg, the northern station area, and especially the southern districts, which was the only direction that could be occupied by residential development. However, the growth led to a disproportion, as there were no religious or educational institutions in the area. Such disproportions were among the most important challenges faced by the large urban centres of Russia, which were the driving force of late Imperial modernisation.
Female “Singleness” in the Urals around 1900
Authors:   Institute of History and Archaeology UB RAS, Ekaterinburg, Glavatskaya Elena M. ,   Ural Federal University, Ekaterinburg, Bobitsky Alexandr V. ,   Institute of History and Archaeology UB RAS, Ekaterinburg, Zabolotnykh Elizaveta A. ,   Institute of History and Archaeology UB RAS, Ekaterinburg
Published: February 2024

This paper studies female “singleness”, which is defined as the status of being non-married, in the cities of Perm Province. Emphasis is placed on the two largest cities — Perm and Ekaterinburg — compared with the entire urban and rural population. The authors refer to aggregates from the city censuses taken in Perm and Ekaterinburg as well as the national censuses of 1897 and 1926 as the main sources. The study quantitatively analyses women’s marital status in relation to age, place of residence, ethno-religious, and social affiliation, and calculates the rate of women who never married and singulate mean age at marriage. During the second half of the nineteenth century, in Perm and Ekaterinburg, the authors observe stability in the marriage structure among the female population. Over 50% of urban women and 33.6% of rural women aged 15 and older were not married: in the group under 30 years old, female “singleness” was determined by the fact that some girls were unable to marry. By the age of 40, a significant part of those “single” women were widows, and in the age group of 40–49, they made up the majority. Divorce was significantly less likely to be the cause of female “singleness” than non-marriage while still fertile. The differences in the level of female “singleness” in the Perm cities were influenced by the in-migration of female servants, whose background was often rooted in the peasant class, and the presence of a large monastery. During the new Soviet reality, renunciation of marriage as a life trajectory became infrequent, while the proportion of divorced people among those “single” increased noticeably.
Mechanics of Government Reformism: A Note by Provincial Leader N. A. Maikov and the Practice of Adjusting the Legislation on Noblemen’s Elections in Russia in the First Third of the 19th Century
Authors:   Institute of History and Archaeology UB RAS, Ekaterinburg, Timofeev Dmirii V.
Published: February 2024

As part of the examination of the formation processes of public sphere elements in Russia, this article studies the peculiarities of functioning of mechanisms of forward and backward communication in the system of management of the first third of the nineteenth century. In this context, the public sphere is seen as a network of actors and information channels that provide an opportunity for individuals to express various arguments when discussing the most pressing socio-political, economic, and moral issues. The author analyses the complex of records management materials and decrees related to the process of consideration and decision-making on the issues of adjusting the legislation on elections among the nobility. A reference to a note by N. A. Maykov, a provincial governor of the nobility, shows the arguments for the need to adjust the legislation on elections and the response to the proposals of the Minister of Internal Affairs, members of the Committee of Ministers, the State Council, and the Senate. A comparison of the reports of the marshals of the nobility, governors, records of meetings, legislation, preceding and following Maykov’s note, make it possible to formulate several important features of the functioning of feedback mechanisms in Russia in the period under consideration. The slow response to signals from the field happened because decisions were not always communicated to their direct implementers. This led to a duplication of requests and multiple discussions on the same issues, but in general did not prevent the institutions of power from being informed about the contradictions between the legislation and reality. This is confirmed by the results of a comparative analysis of the questions and proposals formulated by Maykov, with the content of subsequent decrees and the new “Regulations on the Order of Nobility Assemblies of Elections and Service on Them” of 1831.
Many-Faced Carnelian: The History of the Names of the Stone in the Russian Language Tradition
Authors:   Ural Federal University, Ekaterinburg, Kuchko Valeria S.
Published: February 2024

This article studies the history behind the nominations of carnelian that have existed at different times within the Russian language tradition. They are loans from the ancient Greek language сардион, сардий, сардоних and сардоникии; Western European loans of Modern times карнеол, корналин; and the word сердолик which is native, but in many respects formally “induced” by the appearance of loanwords that already existed in the language. The fact of the multiplicity of nominations of this stone is due to several reasons: the antiquity of humankind’s acquaintance with this stone and the occurrence of its mentions in ancient texts that influenced the formation of the book culture of Old Rus’; the imported origin of the stone and only very late discovery of its home deposits; a specific linguistic and cultural situation that arose during the formation of the Russian scientific terminological system, when there was competition between the original names of the mineral and new Western European analogues, acquaintance with which occurred through the translation of mineralogical treatises. The article describes the factors that create the specifics of the linguistic history of carnelian, which are in different combinations characteristic of the whole area of the history of mineralogical names. The author comments on the time of the appearance of borrowed names of carnelian in the Russian language, their sources, the difference in the sphere of use, and semantic shades. Also, the article provides data on the time and reasons for the occurrence of the word сердолик, as well as its motivation based on intra-linguistic and extralinguistic factors, the existence of terminological parallelism with the participation of different names of carnelian, and competition between native and borrowed names.
Development Trends and Dynamics of Industrial Specialization in Russian Regions
Authors:   Institute of Economics of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russian Federation, Kotlyarova Svetlana N. , Shamova Elena A. ,   Institute of Economics of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russian Federation
Published: February 2024

Relevance. The study of the industrial structure of regional economies has gained relevance amid shifting geopolitics and unprecedented sanctions, prompting the need for economic restructuring, product/sector substitution, and the exploration of new growth opportunities at national and regional levels. Research objective. This study evaluates the dynamics of industrial specializations in Russian regions and their role in ensuring stable regional economic development. The hypothesis is that there is a direct link between the resilience of the regional economic system and its industrial specializations. Here, resilience refers to the territory's ability to minimize the negative impacts of external shocks and threats and restore its economic level during a specified adaptation period. Data and method. The focus of this study is industrially developed regions whose economies rely predominantly on manufacturing. The study uses Rosstat data on shipped goods, performed works, and services from 2019 to 2022. Data cleansing involves removing the inflationary component using producer price indices. The Herfindahl-Hirschman Index is used for the sectors in the "C. Manufacturing" category of OKVED2 (All-Russian Classifier of Economic Activities). Results. The study identifies regional variations in industrial specialization levels and progression, categorizing regions into diversified and specialized. We found the transformation of the economic structure in the majority of the examined regions and identified the "new" and "departed" sectors of industrial specialization. Resilience to crises is analyzed, revealing three groups of regions based on their resilience levels. Key industries driving regional development are also identified. Conclusions. Analysis of industrially developed regions uncovers unique structural transformations, offering valuable insights for regional policymakers. Future research avenues may involve refining socio-economic profiles based on industrial specialization and formulating government measures to support industrial development.
The effect of COVID-19 restrictions (lockdown) on GDP growth in CIS countries
Authors:   Ural Federal University, Ekaterinburg, Russian Federation, Dzhuraeva Zarnigor , Okrah James ,   Ural Federal University, Ekaterinburg, Russian Federation, Naziri Gulbahor N. ,   National Bank of Tajikistan, Dushanbe, Tajikistan
Published: February 2024

Relevance. Global economy has suffered significant economic consequences as a result of the COVID-19. The impact of the pandemic crisis had generally been felt around the world. However, developing economies, with their many institutional constraints, have been much more affected by the crisis. This prompted governments to devise stringent policies to limit its destructiveness, with the goal of saving the populace while minimizing economic damage. Research objective. We investigate the effect of government's stringent policies on economic growth and the influence of stringent policies and inflation on economic growth in CIS's countries. Data and methods. Our analysis is conducted using quantile regression, which is an extension of the Johnson-Neumann interval OLS, and a simple slope analysis for the period from 1 March 2020 to 17 September 2021. Results. Our findings show that the government's stringent policies have a negative effect on economy, reducing GDP growth by 4.9% in the mean model. Excessively stringent policies have a negative impact on the economy and the consequent decline in living conditions. Conclusions. The findings of this study reveal that policymakers should take a targeted approach to COVID policies, considering the varying effects of stringency across different levels of economic growth and taking into account the potential interaction with inflation rates. By implementing policies that balance the need for public health and economic growth, policymakers can mitigate the negative impacts of COVID restrictions on the economy and minimize the risk of stagnation traps.
Challenges and potential of monotowns: a systematic literature review
Authors:   Marmara University, İstanbul, Türkiye, Dirsehan Taşkın ,   Erasmus University School of Social and Behavioral Sciences, Rotterdam, Netherlands, Shurenov Nursultan ,   Al-Farabi Kazakh National University, Almaty, Kazakhstan, Tovma Nataliya ,   Al-Farabi Kazakh National University, Almaty, Kazakhstan, Kozhamkulova Zhanna ,   Al-Farabi Kazakh National University, Almaty, Kazakhstan, Akhmetova Zauresh ,   Al-Farabi Kazakh National University, Almaty, Kazakhstan
Published: February 2024

Relevance. Monotowns, or single-industry settlements, are pivotal in the economic and social landscapes of former Soviet countries. This systematic literature review explores monotowns, examining their evolution, challenges and implications of these unique urban formations from the 18th century to the present day. The study’s relevance lies in its comprehensive analysis of these towns, which have been significant yet underexplored in academic discourse. Research objective. The objective of this review is to critically examine the multifaceted nature of monotowns, focusing on their socio-economic dynamics, challenges, and potential transformation. The review aims to elucidate the complex interplay of economic, social, and political factors that shape these towns and to identify unexplored areas in this field of study. Data and Methods. To achieve these objectives, the study employs a systematic review protocol comprising four phases: search query, document type, publication stage, and language. This approach involves analyzing a wide range of sources from international and regional databases, ensuring a holistic view of monotowns that captures both historical and contemporary perspectives. Results. Monotowns exhibit considerable resilience amidst economic fluctuations and confront distinct socio-economic challenges, including issues specific to mining monotowns and issues related to public health. The findings underscore the importance of adaptive strategies, corporate social responsibility, and proactive government intervention in addressing these challenges. Conclusion. This review provides a comprehensive exploration of monotowns, contributing valuable insights for future research, particularly in understanding their socio-economic dynamics and the challenges they face. The study is significant for scholars in economic development of the territories and business studies, offering a foundation for further exploration of these unique urban formations.
Desigualdade educacional e valorização docente: uma análise de convergência do Ideb condicionado ao financiamento da Educação Básica pública
Authors: Lima Sergiany da Silva , Silva Carlos Daniel da , Poziomyck Arthur
Published: February 2024

O objetivo desta pesquisa consiste em analisar as desigualdades educacionais por grandes regiões e municípios brasileiros segundo os resultados do Índice de Desenvolvimento da Educação Básica (Ideb) condicionado ao financiamento do Fundo de Manutenção e Desenvolvimento da Educação Básica (Fundeb). A principal hipótese de investigação é de que o resultado da política de financiamento educacional seja influenciado pela qualidade institucional. Para isso, foi empregado um modelo de convergência condicional de renda adaptado para o Ideb dos anos iniciais da Educação Básica. A relação do financiamento educacional com o crescimento do Ideb foi estimada por Mínimos Quadrados em Dois Estágios (MQ2E), para instrumentalizar o Fundeb através de variáveis da qualidade das instituições municipais. Os resultados da pesquisa confirmam a hipótese de que a qualidade institucional é estatisticamente relevante para explicar o crescimento do Ideb e as suas desigualdades. Com essa especificação endógena, o efeito do financiamento sobre o Ideb é fortemente aumentado, demonstrando a importância da valorização docente e do aprimoramento das instituições para o desenvolvimento da Educação Básica.
O papel da argumentação na aquisição da linguagem e no processo de aprendizagem de crianças surdas em escolas bilíngues
Authors: Silva Ana Clara Jardim da , Vieira Alessandra Jacqueline
Published: February 2024

Para Leitão (2007a; 2007b), a argumentação é um mecanismo privilegiado para a aquisição da linguagem e do conhecimento, perpassando dimensões como a dialógico-discursiva, dialética, social e epistêmica. Demonstra-se, assim, a importância de desenvolvê-la nos primeiros anos escolares, sobretudo em escolas bilíngues. O objetivo deste estudo é, portanto, analisar os discursos argumentativos produzidos por crianças surdas, buscando identificar os encadeamentos enunciativo-discursivos que geram a argumentação e as mudanças epistêmicas geradas pelo efeito desses discursos argumentativos. Para tanto, foram realizadas coletas de dados em três escolas bilíngues (Português-Libras), voltadas à educação de surdos, abarcando uma amostra de 23 sujeitos, entre 6 e 14 anos, onde foram observadas situações naturalísticas e provocadas por oficinas lúdicas. Amparando-se nos estudos em argumentação (LEITÃO, 2006, 2007a; VIEIRA, 2015), multimodalidade (SOUSA; MÁXIMO, 2009; CAVALCANTE, 2016; 2011) e dialogismo (VOLÓCHINOV; BAKHTIN, 2018; BAKHTIN, 2016), pôde-se concluir que a argumentação estimula movimentos discursivos e linguísticos (como retomada de enunciados, leitura do contexto e organização sintática) e multimodais (expressão facial, gestos sociais, uso do corpo, etc) que corroboram à aquisição bilíngue bimodal. Assim, a argumentação contribui à entrada da criança surda na língua e favorece o processo interacional, que é de extrema importância à formação do pensamento crítico e ao desenvolvimento linguageiro esperado.
Manufacture of Platinum Fibre and Fabric - A Technical Note on An Interesting Material, Some Properties and Uses
Authors: Mori Kenya
Published: February 2024

Since 1996, Tanaka Kikinzoku Kogyo K.K. has been producing flocculate platinum fibre and non-woven fabric made from this fibre. The background to the production of this material is briefly described. Flocculate platinum fibre and fabric are currently used as filtering materials in filtering applications that require both heat and chemical resistance. The platinum fibre and fabric are also finding application as electrically conductive fillers for porcelain enamel.
Derivatives of Magnus’ Green Salt
Authors: Caseri Walter
Published: February 2024

Magnus’ green salt is a quasi-one-dimensional compound of composition [Pt(NH3)4][PtCl4] comprising linear arrays of platinum(II) ions. It is essentially insoluble in water and organic solvents and therefore difficult to process, which limits its use. Recently, soluble and thus processible derivatives of Magnus’ green salt have been synthesised by substituting the ammonia by linear and branched aminoalkanes. The Pt-Pt distances and the properties of these Magnus’ salt derivatives depend on the detailed structure of the aminoalkane. In particular, in compounds with branched aminoalkanes weak but noteworthy interactions arise between adjacent platinum atoms, as is evident from their colour, their electrical conductivity, and their UV and IR spectra. Compounds with optically active branched aminoalkanes exhibit circular dichroism with a bisignate Cotton effect and unusually high absolute values for the chiral anisotropy factors. The complex [Pt(NH2dmoc)4][PtCl4] with dmoc designating (S)-3,7-dimethyloctyl is of particular importance since its colour and electrical conductivity strongly resemble those of Magnus’ green salt. Films of [Pt(NH2dmoc)4][PtCl4] can function as an active semiconducting layer in field effect transistors. Remarkably, such devices have superior stability in air and water to unprotected field effect transistors fabricated with typical organic polymers. Hence, Magnus’ salt derivatives might find use in components of mass-produced “plastic electronics”.
The Structure of Rhodium
Authors: Bale E. S.
Published: February 2024

This note, a communication from the Johnson Matthey Research Laboratories, records an investigation into the crystal structure of high-purity rhodium carried out in an attempt to understand why this metal should present such difficulties in working
The Ammonia Oxidation Process for Nitric Acid Manufacture
Authors: Hunt L. B.
Published: February 2024

It is little more than fifty years since the first manufacture of nitric acid by the oxidation of ammonia over a platinum catalyst. Ostwald’s original industrial plant had an output of some 100 tons of acid a year; today the world capacity for nitric acid manufacture by this process is about ten million tons a year. This article traces the beginnings and early developments of the process until it became commercially established.
The Development of the Modern Ammonia Oxidation Process
Authors: Holmes A. W.
Published: February 2024

By the end of the first world war the manufacture of nitric acid by ammonia oxidation over a platinum catalyst was a technically established process. The rapid increase in production of synthetic ammonia enabled this method to become the principal source of industrial nitric acid, and further development of the process in terms both of technical progress and in the size of unit plant has been determined by economic factors.
Ruthenium and Osmium as Hydrogenation Catalysts
Authors: Bond G. C. , Webb G.
Published: February 2024

Little attention has been given to the use of ruthenium and osmium as catalysts for vapour-phase reactions. This paper shows that both these metals when supported on alumina possess significant activity for the hydrogenation of unsaturated hydrocarbons. In the hydrogenation of butene, butadiene and acetylene their activity is comparable with that shown by the other platinum group metals, although ruthenium is generally more active than osmium.
Combustion Efficiency in Gas Turbine Engines
Authors: Stewart P. J.
Published: February 2024

Improvement in design of a gas turbine engine depends to a great extent upon achieving the optimum temperature distribution across the combustion chamber. In order to study this and so to be able to modify design a comprehensive series of temperature readings must be made across the combustion discharge nozzle. This article describes the test-bed procedure adopted by Rolls-Royce to provide the information required, the measurements being made with platinum thermocouples housed in specially designed probes. To withstand the high temperatures and pressures involved these probes are constructed in 40 per cent rhodium-platinum.
Temperature Measurement with the Expendable Immersion Thermocouple
Authors: Stevenson J. A.
Published: February 2024

The expendable immersion thermocouple, developed by Leeds and Northrup to give greater accuracy, speed and convenience in the measurement of molten metal temperatures, has now been in use in a number of steelworks for some time. It has also begun to find a place in the melting of non-ferrous metals. This article surveys the results of experiences so far obtained in replacing the conventional platinum rhodium-platinum immersion thermocouple with the expendable cartridge type.
Continuous Temperature Measurement of Molten Steel
Authors: Sharp John D.
Published: February 2024

Following the development of rapid methods of steel analysis the need for greater control of bath temperature has become important, particularly in melting shops using oxygen lancing techniques. In arc furnaces there is also the opportunity of using the temperature to control the power input during refining. This article describes the development of a water-cooled thermocouple probe for continuous immersion.
Organometallic Compounds of the Platinum Metals
Authors: Wilkinson G.
Published: February 2024

Although platinum provided the first known example of an organometallic complex of a transition metal, intensive studies of compounds of the platinum metals with metal to carbon bonds have come mainly during the past decade. The main classes of stable organo-complexes such as those having olefins, acetylenes, alkyl or cyclopentadienyl groups as ligands are discussed. The study of such stable complexes should assist in the elucidation of the mechanism of various reactions which are catalysed by platinum metal salts or complexes.
Platinum Metals in the Fuel Cell
Authors: Oswin H.G.
Published: February 2024

The high catalytic activity exhibited by some of the platinum group metals, together with their excellent resistance to corrosion, form the basis of their applications in fuel cells. In this article the author describes the use of these metals in cells fuelled by hydrogen/oxygen, ammonia, hydrazine and hydrocarbons. The kinetics of the electro-chemical oxidation of hydrocarbons are examined, a mechanism of electrode poisoning is discussed, and finally the author comments on the likely usage of platinum metals in fuel cell technology.
The Platinum Metals in the Production of Laser Crystals
Authors: Cockayne B.
Published: February 2024

Because of their high melting points and lack of chemical reactivity with oxide materials at high temperatures, several of the platinum metals are very useful as container materials for molten oxides. This article describes the use of platinum, rhodium and iridium in the vertical pulling of oxide crystals from the melt. Such crystals form the basis of many solid state lasers and other electronic devices.
Chemistry of the Platinum Metals
Authors: F. M. L.
Published: February 2024

As part of the 158th National Meeting of the American Chemical Society, held in New York in September, a Symposium on the Platinum Group Metals was organised. This review outlines the papers presented, and deals also with a number of other papers given during the remainder of the meeting.
Platinum-Carbon Catalysts with Molecular Sieve Properties
Authors: Cooper B. J.
Published: February 2024

Applications of molecular sieve materials have become of increasing interest in catalysis. The ability of these materials to differentiate on the basis of molecular size gives them a unique form of selective catalytic action with the additional benefit of high resistance to sorption of large poison molecules. Hitherto their major application has been realised with zeolites but new platinum catalysts possessing similar properties and based on a carbonaceous structure have now been developed in the Johnson Matthey Research Laboratories.
Platinum Metal Thermocouples
Authors: Quinn T. J. , Chandler T. R. D.
Published: February 2024

As a result of a remarkable piece of international collaboration between three national standards laboratories and seven United States and United Kingdom manufacturers, new reference tables have now been completed for platinum : 10 per cent rhodium-platinum and platinum: 13 per cent rhodium-platinum thermocouples. These new tables take into account the changes in the temperature scale resulting from the introduction of the International Practical Temperature Scale of 1968 (IPTS-68) and also provide reference tables which will be common to both U.S. and U.K. manufacturers and users of thermocouples.
Supported Homogeneous Catalysts
Authors: Michalska Zofia M. , Webster David E.
Published: February 2024

Almost all industrial catalysts are heterogeneous, the reaction taking place on a solid surface. During the past decade homogeneous catalysts, soluble in the liquid phase reactant, have received a great deal of attention, although they have so far found only limited industrial use, chiefly because of the difficulty of their separation from the reaction products. More recently an intermediate type, made by attaching the active metal complex to an insoluble polymer support, has been found to offer a promising new range of catalysts for the future. It is likely that a large proportion of these will be based on the platinum group metals.
Stabilised Carbonium Ions in the Organic Chemistry of Platinum
Authors: Chisholm M.H.
Published: February 2024

This account of research on the organometallic chemistry of platinum summarises work which indicates that platinum may induce carbonium ion reactivity in π-bonded hydrocarbon ligands and stabilise carbonium ions in the reactions of σ-bonded unsaturated hydrocarbons. It is based on a lecture at the Chemical Society annual meeting held at York in April.
Platinum Provides Protection for Steel Structures
Authors: Shreir Lionel L.
Published: February 2024

Increasing concern at the waste caused by corrosion has focused attention on the need to utilise the most advanced methods for preventing, or controlling, this expensive phenomenon. The use of platinum for the cathodic protection of ships and marine structures is by no means new but the high cost of such structures, the aggressive environmental conditions to which they are subjected in service, and the need for maximum reliability over long periods of time all tend to make platinum cathodic protection an economic alternative to other methods. This review, which will appear in two parts, describes how cathodic protection is provided, outlines the many factors that have to be considered when utilising this method and describes some of the most recent applications.
The Platinum Notebooks of William Hyde Wollaston
Authors: Usselman Melvyn C.
Published: February 2024

Examination of the laboratory notebooks of W. H. Wollaston makes possible a complete reconstruction of his platinum researches, and valuable insights into the financial details of his platinum business, originally in partnership with Smithson Tennant, may be obtained. The leading role played by Wollaston in both the research and marketing aspects of the business is confirmed. Although the use of platinum for laboratory ware and vessels for the concentration of sulphuric acid were important applications, the gunmakers provided the greatest market for malleable platinum over the years 1808 to 1820. The business ground to a halt in 1820 when Wollaston could no longer procure supplies of crude platinum.
Separating the Platinum Group Metals by Liquid–Liquid Extraction
Authors: Charlesworth P.
Published: February 2024

To extract the platinum group metals from the ore, and to refine them to the very high purity required for their many applications, requires a multitude of complex operations. At present the final refining stage that produces the individual platinum group metals is carried out by selective precipitation from a solution of mixed platinum group metals, but this is inefficient as far as the degree of separation is concerned. An improved process which makes use of liquid–liquid extraction has been developed to a pilot plant stage, and this paper highlights some of the chemical and process principles that underlie this method of separation.
Rhodium Sets New Standards
Authors: Buchal Ch. , Welter J.-M.
Published: February 2024

What does the ground state of conduction electrons of metals look like, if the temperature is lowered further and further? This question has been fascinating low temperature physicists for a long time. Nowadays we know that most metallic elements become superconducting at sufficiently low temperatures. In 1964 the superconductivity of tungsten was discovered by lowering the temperature to 15 mK above absolute zero. After a long pause due to the limits of refrigeration, a new superconducting element has now been discovered: rhodium. Various samples fabricated with rhodium sponge were installed in a special set-up in the world’s most powerful refrigerator at the Kernforschungsanlage Jülich. Temperatures down to 50 μK were used to investigate the superconductive properties of rhodium, which shows a superconductive transition at 325 μK.
Michael Faraday’s Use of Platinum in His Researches on Optical Glass
Authors: Usselman Melvyn C.
Published: February 2024

In 1824, the British government sought to keep pace with continental advances in optical glass manufacture by funding research into the area. Faraday was put in charge of the experimental investigation and he relied heavily on platinum for vessels and instruments. Throughout the researches he was aided by William Hyde Wollaston, who manufactured and supplied the platinum initially used.
Electrodeposition of Palladium-Silver Alloys from Ammoniacal Electrolytes
Authors: Sturzenegger B. , Puippe J. Cl.
Published: February 2024

A viable technique for the electrodeposition of palladium-silver alloys could find application during the manufacture of electrical contacts. Previously such a process has not been available but some alloys with useful physical properties can now be deposited from an ammoniacal system, while a better understanding of the mechanisms involved has been gained during the work reported here.
Redistribution of Platinum Metals within an Ammonia Oxidation Plant
Authors: Fierro J. L. G. , Palacios J. M. , Tomás F.
Published: February 2024

The powder recovered from the catalyst and catchment systems in a high pressure ammonia oxidation plant has been studied by a variety of analytical means. From this investigation it can be concluded that the powder results from the in-depth degradation of the platinum-rhodium catalyst gauzes and the palladium-copper catchment gauzes, together with impurities arising from the reactor constructional materials. The results indicate two different transport mechanisms, and the study may assist in the development of more stable platinum-based catalysts and catchment packages for nitric acid plants.
Platinum Metals In Stainless Steels
Authors: McGill I. R.
Published: February 2024

The range of iron-based materials known as stainless steels are used throughout the world to manufacture products requiring special resistance to corrosive environments. The corrosion resistance of these materials depends largely upon the chromium content, which is usually between 10 and 30 per cent of the alloy constitution. Of equal significance is the ability to vary the structure of the alloy between ferritic, austenitic and martensitic, by control of the type and level of additional elements. There are, however, many corrosion limiting factors which restrict the use of each type of steel, and the addition of noble metals to the iron-base constitution, to improve this situation, has been considered. This article summarises most of the published work on the effects of platinum group metals on the corrosion and mechanical properties of stainless steels, but excludes investigations of non-stainless steels.
The Use of Platinum by Carl Fabergé
Authors: Dale Stephen R.
Published: February 2024

Combining imaginative design with outstanding craftsmanship, the decorative objects made by Fabergé for many years Goldsmith to the Imperial Court of Russia, were intended not only to delight but also, in many instances, to amuse those fortunate enough to receive them. The masterpieces produced in his workshops continue to be highly regarded by museums and private collectors, and demonstrate his ability to use a wide variety of precious materials, including platinum and its alloys, to create fascinating objects for a privileged clientele, which was later destroyed or dispersed by the combined effects of the First World War and the Russian Revolution.
Geoffrey Wilkinson and Platinum Metals Chemistry
Authors: Green M. L. H. , Griffith W. P.
Published: February 2024

At this time, the second anniversary of Geoffrey Wilkinson’s death on 26th September 1996, his work and influence on the development of inorganic chemistry and the chemistry of the platinum group metals are recalled by two of his former students and colleagues. Geoffrey Wilkinson’s
early life and career, important areas of his platinum metals research and work leading to the award in 1973 of the Nobel Prize are surveyed. He is remembered by his relationship with Johnson Matthey, his work at Imperial College and by affectionate anecdotes from the laboratory.
Twenty-Five Years of Autocatalysts
Authors: Twigg Martyn V.
Published: February 2024

A quarter of a century ago the first autocatalysts were manufactured on a commercial scale by Johnson Matthey at Royston, near Cambridge, in England. This article looks at the background to this major contribution towards cleaning urban air and briefly traces the progress of car catalyst
technology since the work of the early autocatalyst pioneers.
Comparison of fresh and hardened properties of concrete made with various artificial and natural sands
Authors: Nguyen Duc-Trong , Nguyen Duy-Liem
Published: February 2024

Concretes made with different fine aggregates (natural river sand, artificial crushed sand, artificial gravel sand and a hybrid sand (50% river sand and 50% gravel sand by mass)) were experimentally investigated. The concretes were found to have little differences in compressive strength and elastic modulus (less than 6.4%). Compared with the concrete made with natural river sand, the concretes made with artificial sands demonstrated higher flexural strengths (3.5–11.1%) and splitting strengths (4.4–12.8%) at 28 days, but lower workability (21.4–35.7%), water permeation resistance (34.3–53.7%) and abrasion resistance (2.9–20.6%). The compressive, flexural and splitting tensile strengths of the concretes increased with time under water curing. Under sulfate attack, the compressive strengths of the concretes were enhanced at 56 days but reduced at 90 days. In comparison with water curing, the reductions in compressive strength due to sulfate attack were 2.6–7.7% at 56 days and 11.8–24.4% at 90 days. Weibull distribution analysis was conducted to explore the sensitivity of concrete strength to the type of fine aggregate.
Synergism of steel fibres and PVA fibres on the fracture and mechanical properties of ultra-high-performance concrete
Authors: Liu Junxia , Zang Shujie , Yang Fei
Published: February 2024

The influence of the volume fraction (VF) of steel fibres, polyvinyl alcohol (PVA) fibres and their combination on the mechanical and fracture mechanical properties of ultra-high-performance concrete (UHPC) was studied. To analyse the synergistic effect of steel fibres and PVA fibres on the deformation properties of UHPC, the gain ratios (the ratios of the mechanical properties of UHPC reinforced with hybrid fibres (HUHPC) with those of UHPC reinforced with steel fibres (SUHPC)) were obtained for equal total fibre VFs and equal steel fibre VFs. The steel and PVA fibres reduced the compressive strength of the UHPC to some extent and, with increasing VF, the ratios of flexural strength/compressive strength and tensile strength/compressive strength increased gradually. The fracture mechanical properties of the UHPC were significantly improved with the addition of steel fibres and PVA fibres; the latter were superior in improving the deformation properties of the UHPC. Except for compressive strength, the gain ratios of mechanical parameters of HUHPC to SUHPC calculated with equal steel fibre VF were higher than for equal total fibre VF; 0.25% PVA fibres mixed with SUHPC further improved the bending tensile and fracture mechanical properties.
Clinical characteristics of children and adolescents admitted with chest pain
Authors: ÜNVER Gülden , SERT Ahmet
Published: February 2024

Abstract Background: Chest pain is a common disease in children. Chest pain is the second most common symptom referred to by paediatric cardiologists after cardiac murmurs. Objective: In this prospective study, we aimed to evaluate clinical characteristics and causes of chest pain in children admitted to our paediatric cardiology outpatient clinics. Methods: We conducted this prospective study among 446 patients with chest pain in a tertiary care hospital from 1 June 2017 to 1 June 2020. The demographic data and clinical characteristics of the patients were analysed. All patients were evaluated with a medical history, physical examination, laboratory tests, electrocardiogram and echocardiogram and if necessary telecardiogram, 24-hour electrocardiogram monitoring, exercise stress test and psychological evaluation were made. Results: The ratio of admissions with acute pain was 4% when 20% of the patients had chronic chest pain. The most common symptoms associated with chest pain were shortness of breath and palpitations. The non-cardiac causes were as follows: 25% musculoskeletal, 14% psychological, 9% respiratory, and 7% gastrointestinal, respectively. We found cardiac chest pain in 49 (11%) of patients. Idiopathic chest pain was found in 153 (34%) patients. Conclusions: Our study showed that the aetiology of chest pain in children and adolescents admitted with chest pain is mostly due to non-cardiac causes. We found the slightly frequency of elevated rate for cardiac aetiologies of paediatric chest pain compared to the literature. We suggest that in addition to anamnesis and careful examination, further investigation, if necessary, is important in determining the aetiology of chest pain.