bluuebunny/crossref_metadata_2025 huggingface dataset:
El trasplante de útero: una puerta abierta a la posibilidad de tener hijos
Authors: Aguilar Crespo Alejandra , Escrig Estrems Julia , Pamplona Bueno Loida , Quinzá Redondo María José , Díaz García César
Published: February 2024

La infertilidad de origen uterino afecta a una de cada 500 mujeres en edad reproductiva impidiéndoles ser madres biológicas. Es la única causa de esterilidad para la que no se disponía de tratamiento hasta el desarrollo del transplante de útero, que todavía se encuentra en fase experimental. Los resultados del grupo de investigación del Dr. Brännström de Suecia están siendo prometedores, habiendo nacido cinco bebés sanos gracias a esta técnica. Se prevé una inminente demanda y polémica social en torno a los aspectos éticos y legales que la rodean. Las alternativas con las que cuentan las pacientes con este tipo de esterilidad son la adopción y la maternidad subrogada o vientre de alquiler. Ambas plantean también un reto ético-legal significativo que revisamos en el artículo. En el contexto de la legislación española, el uso de vientres de alquiler está prohibido, por lo que el trasplante de útero puede ser una solución alternativa para conseguir la maternidad en mujeres con esterilidad por causa uterina absoluta.Abstract:Uterine factor infertility affects one in 500 women on reproductive age preventing them from being biological mothers. It is the only cause of sterility for which treatment was not available until uterine transplantation was developed, although it remains an experimental technique. The results of Dr. Brännström's research group in Sweden are promising. Five healthy babies have been born after uterus transplantation. We expect an imminent demand and social controversy around the ethical and legal aspects that surround uterus transplantation. The alternatives for patients with this kind of sterility are adoption and surrogacy. Both raise significant ethical and legal issues that we review in this article. In the context of the Spanish legislation, surrogacy is prohibited; therefore, uterine transplantation could be an alternative to achieve motherhood in patients with absolute uterine factor infertility.
El reconocimiento del derecho a la identidad sexual de los menores transexuales en los ámbitos registral, educativo y sanitario
Authors: Maldonado Javier
Published: February 2024

EspañolEl Estado español no reconoce el derecho a la identidad sexual de los menores transexuales, ni prevé un procedimiento especial que permita el cambio de nombre a todos los menores transexuales de acuerdo a su identidad sexual, provocando que sus derechos fundamentales sean vulnerados. La situación de desamparo legal se alivia gracias a la legislación promulgada por la mayoría de las comunidades autónomas en los ámbitos en los que tienen competencias y que son esenciales para los menores, como educación y sanidad.EnglishThe Spanish State does not recognize the right to gender identity of transgender minors, nor does it foresee a special procedure that allows the change the name of all transgender minors according to their gender identity, provoking the violation of their fundamental rights. The situation of legal abandonment is alleviated thanks to the legislation promulgated by the majority of the Autonomous Communities in the areas in which they have competences and that are essential for the minors, like education and health.
Syriza, m5s y podemos: los tres campeones del votante enfadado en el sur de europa
Authors: Cordero Guillermo
Published: February 2024

El artículo examina el perfil de las bases electorales de los tres ejemplos más exitosos de partidos “antiélite” de izquierda en el Sur de Europa: la Coalición de Izquierda Radical (SYRIZA) en Grecia, el Movimiento Cinco Estrellas (M5S) en Italia y Podemos en España. Estos partidos tienen en común la implementación de un discurso populista no de derechas con conexiones en los movimientos de protesta de cada uno de sus países. Utilizando datos de la European Elections Study 2014, nuestro análisis revela que a pesar del hecho de que estos votantes se han descrito como “eurocríticos” y “desideologizados”, nuestro principal hallazgo es que su apoyo electoral descansa principalmente en la ideología y en la desconfianza y falta de apoyo a las élites nacionales.
Proporcionalidad penal: A propósito de la desobediencia leve y de la falta de respeto y consideración debida a la autoridad
Authors: De la Fuente Cardona Francisco Salvador
Published: February 2024

En el presente trabajo se expone el contenido y alcance del principio de proporcionalidad penal. Idoneidad, necesidad y proporcionalidad estricta son los tres niveles de análisis que el jurista debe llevar a cabo para comprobar la proporcionalidad de una norma penal en abstracto, de una medida o de la aplicación de un tipo. Sin embargo, no debemos llevarnos a engaño. Solo en los casos más extremos el principio de proporcionalidad responde a la constitucionalidad de una norma penal concreta, si bien va a ser un poderoso instrumento argumentativo. En la segunda parte del trabajo, aplicaremos este examen de proporcionalidad a la desobediencia leve y a la falta de respeto y consideración debida a la autoridad, antes regulados en el derogado artículo 634CP y hoy reubicados como delito leve e infracción administrativa grave.
Effect of Pulping Processes on Fibre Properties and Paper Structure
Authors:   DEPARTMENT OF CELLULOSE CHEMISTRY, TECHNICAL UNIVERSITY OF NORWAY, TRONDHEIM, Giertz Hans Wilhelm
Published: February 2024

Based on the assumption that the most basic property of a paper is its apparent density, pulping effects such as yield, number of fibres per unit weight, lignin and hemicellulose contents and fibre strength are discussed with reference to the formation of bonds and paper structure. Special attention is devoted to the influence of different hinds of sulphite cooking such as conventional acid sulphite, bisulphite and two-stage cooking, also kraft cooking and bleaching. Finally, non-chemical operations in pulping such as chipping, fibre fractionation and drying are briefly surveyed.
Fundamental Aspects of Filler Distribution in Paper
Authors:   CENTRAAL LABORATORIUM, KONINKLIJKE PAPIERFABRIEKEN VAN GELDER ZONEN N.V., VELSEN, HOLLAND, Groen L. J.
Published: February 2024

An effective and simple method for sectioning paper was developed that enabled determination of the distribution of filler in a large number of papers. Attention was concentrated on papers made on Fourdrinier machines, but, to obtain a complete picture of filler distribution, handsheets and papers made on cylinder machines were also investigated. From the resulting filler distribution curves, it appeared that handsheets and cylinder-made papers have a comparable filler distribution, which is the reverse of that of Fourdrinier-made and handmade papers. It is generally supposed that the filler in Fourdrinier-made papers is concentrated in the top layer, whilst much less filler is present on the wire side. This was confirmed in our investigations. It even turned out that the filler content of a 10 per cent wire side layer is almost constant and depends only in the degree of beating and to some extent on the total amount of filler in the paper. This suggests the filler capacity of the extreme wire side layer to be the determining factor. Furthermore, the influence was investigated of filler retention, type of filler (particle size), fibre composition, filler content, machine speed, dandy roll and open table rolls on filler distribution . From this, some general rules about the distribution of filler in paper were derived: it is determined by machine speed, total filler content and filler capacity of the extreme wire side layer. The filler distribution in the top layers of a Fourdrinier-made paper is affected also by the dandy roll and probably by the retention of the filler. This general picture of filler distribution, together with the results of laboratory and mill experiments, gave rise to a theory of the causes of the observed phenomena. This theory states that self-filtration (drainage) of the three-phase system water|fibre |filler results in a heterogeneous distribution of filler particles in the fibre mat, having the same character as in Fourdrinier-made paper. It is concluded, therefore, that the uneven distribution is already present in the first stage of drainage and is strongly intensified by the extreme drainage conditions.
Development of a pulsed laser deposition system suitable for radioactive thin films growth
Authors: Machado Noé Gabriel Pinheiro , Genezini Frederico Antonio , Raele Marcus Paulo
Published: February 2024

Radioactive thin films have a direct application in the development of beta-voltaic batteries. The main advantage of that kind of nuclear battery is its durability, which can range from a hundred years, depending on the half-life of the radioisotope used. In this context, Pulsed Laser Deposition (PLD) is an important tool. A relevant aspect of a system using this technique is that the main equipment is outside the chamber where the material is processed. Consequently, this feature allows the growth of radioactive thin films, as it enables the development of an arrangement where the contaminated area is controlled. In this way, the present work proposed the development of a PLD system for the growth of radioactive thin films. The PLD system was then implemented and radioactive copper targets were processed for 60 min and 120 min, resulting in radioactive thin films with an average thickness of (167.8 ± 3.7) nm and (313.5 ± 9.2) nm, respectively. Then, a study was performed about the radioactive contamination spread in the PLD system in order to prove if the filtering implemented was effective in retaining the contamination inside the vacuum chamber. Thus, it is demonstrated for the first time the feasibility of using the PLD technique in the growth of radioactive thin films, making its use possible in future studies on the development of beta-voltaic nuclear batteries.
COVID-19 current scenario
Authors: Awasthi LP , Verma HN
Published: February 2024

Outbreak of a highly infectious and lethal human viral diseases was first reported from China during late 2019.In a few months only, it spread to a large number of countries across the globe and many people died because of the lack of any target medicine. So far five human corona viruses have been identified, four of which are known to circulate in the human population, especially in children The viruses causing common cold but rarely infections of the lower respiratory tract were first identified in the mid-1960s Subsequently, a third human corona virus, which caused severe acute respiratory syndrome, with worldwide spread was identified in 2003. It was declared as pandemic in March 2020 by World Health Organization (WHO), since it spread rapidly across the globe in a very short span of time with considerable rate of mortality.
The importance of geometric algebra in the language of physics
Authors: Sen D , Sen Deeprodyuti
Published: February 2024

Geometric algebra has emerged as the preferred mathematical framework for physics because it provides compact and intuitive descriptions in many areas including classical and quantum mechanics, electromagnetic theory and relativity. Geometric algebra has also found prolific applications as a computational tool in computer graphics and robotics. Leading exponents of this extensive mathematical apparatus are fervently insisting its inclusion in the undergraduate physics curriculum.
“[…]Ante el augusto tribunal de la opinión pública” : opinión pública, impresos y honor en el Caribe neogranadino, 1831-1857
Authors: Flórez-Bolívar Roicer
Published: February 2024

El artículo analiza la relación entre opinión pública, impresos y honor en el Caribe neogranadino entre 1831 y 1857. Se argumenta que, adicional a la prensa, textos impresos como folletos, hojas volantes, anónimos, panfletos y pasquines jugaron un importante papel en la construcción y desarrollo de la opinión pública ya que a través de estos se ejercía control sobre  el funcionamiento del Estado, desempeño de funcionarios y ministros de la Iglesia, la vida privada de los ciudadanos y otros. La fuente principal del estudio fueron 99 impresos —folletos, hojas volantes, anónimos y pasquines—y un manuscrito que reposan en la hemeroteca de la Biblioteca Nacional de Colombia. Esta investigación busca enriquecer las interpretaciones planteadas por la historiografía colombiana sobre la construcción de la opinión pública durante el siglo XIX. Una de sus conclusiones es que el análisis de las fuentes referenciadas es una ventana que nos aproxima a la cultura política de los habitantes de la región del Caribe neogranadino al mostrarnos como asimilaron e interiorizaron conceptos e imaginarios de la sociedad colonial como el honor y otros del vocabulario republicano como ciudadanía, libertad de opinión y debate.
From greenwashing to screenwashing?
Authors: Koning Ina Maria , van den Eijnden Regina J.J.M. , Vossen Helen G.M.
Published: February 2024

In this viewpoint, we introduce the term ‘screenwashing’, which describes the phenomenon whereby social media platforms, such as TikTok and Instagram, pretend to be more socially responsible than they actually are. That is, social media platforms pretend to be thoughtful about children's health and the prevention of problematic social media use, but this often turns out to be nothing more than “a lick of paint”. We describe how features like the one-hour notification on TikTok and Instagram are considered screenwashing and why we believe so. Screenwashing, an unethical practice, has the potential to mislead parents and young users. Consequently, we advocate for increased government intervention to protect our youth from the potential hazards associated with problematic social media use.
Designing for health: A study of architecturally oriented models of public space
Authors: Tu Kangwei , Reith Andras
Published: February 2024

In the post-pandemic period, cities are committed to creating healthier and more healing urban environments. In high-density urban environments, urban complexes are increasingly assuming the function of enriching the external space and activating the vitality of cities, and their architecturally oriented public spaces have great potential for the promotion of residents' health. However, current research on public space and health has focused on green spaces and neighborhoods, and has not yet systematically sorted out the pathways that influence how building-oriented public space can contribute to health. In order to fill the gap, this study attempt to establish a model of health-promoting architecturally oriented public space, which can provide a reference for the similar projects.
Role of vitamin D in the genesis of recurrent reproductive loss
Authors:   Bogomolets National Medical University, Kyiv, Ukraine, Poladich I.V. , Kostenko O.Yu. ,   Bogomolets National Medical University, Kyiv, Ukraine
Published: February 2024

Currently, there is active discussion worldwide regarding the impact of vitamin D deficiency and the manifestations of its immunosuppressive properties on the development of recurrent pregnancy loss. Vitamin D deficiency and insufficiency are quite common, with prevalence ranging from 35% to 80%. Despite modern molecular-genetic technologies, the question of polymorphisms in the vitamin D receptor (VDR) genes remains relevant. Purpose - analysis of the relationship between VDR genes polymorphisms in women affected by recurrent reproductive loss. A systematic search of published literature with a meta-analysis was conducted using the PubMed, Web of Science, and Scopus databases for the period from 2021 to 2022. This review examines the association VDR in women with recurrent reproductive losses. There is a connection between low vitamin D levels and the risk of developing various somatic diseases. The review of scientific data confirmed information about the comorbidity of diseases related to vitamin D deficiency or insufficiency. Thus, extragenital pathology creates unfavorable conditions for recurrent pregnancy losses, limits adaptive mechanisms, and contributes to the exacerbation of complications that may arise due to vitamin D deficiency or insufficiency. During the review, it was found that the most prevalent and well-studied polymorphic variants of the VDR gene, such as FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232), TaqI (rs731236), and Cdx2, are associated with various diseases, including reproductive losses. In particular, the FokI polymorphism (rs2228570) of the VDR gene acts as an independent factor capable of predicting the level of vitamin D in the blood, influencing pregnancy outcomes. Conclusions. The obtained data represent significant information for assessing the risk of recurrent reproductive losses and developing new strategies for the prevention and treatment of these conditions. No conflict of interests was declared by the authors.
THE EFFECT OF THE IMPLEMENTATION OF PSAK 109 AND THE INTERNAL CONTROL SYSTEM ON GOOD ZAKAT GOVERNANCE IN BAZNAS REGENCY/CITY IN WEST JAVA
Authors: Yulianti Lina
Published: February 2024

AbstrakLahirnya UU Zakat Nomor 23 Tahun 2011 serta terbitnya standar akuntansi zakat menumbuhkan harapan baru terhadap pengelolaan zakat di Indonesia. Untuk mencapai tujuan pengelolaan tersebut maka zakat harus dikelola dengan baik, amanah dan transparan. PSAK 109 diberlakukan sebagai pedoman dalam penyusunan laporan keuangan di lembaga zakat. Namun pada prakteknya, PSAK 109 masih belum diterapkan secara merata. Selain itu beberapa hasil riset menunjukan bahwa zakat belum dikelola dengan baik, masih terdapat kendala dalam pengelolaannya. Studi ini mencoba menjelaskan tentang pengaruh penerapan  PSAK 109 dan pelaksanaan sistem  pengendalian intern. terhadap good  zakat governance. Penelitian ini menggunakan metode kuantitatif dan dilakukan pada BAZNAS kab/kota di Jawa Barat. Hasil penelitian menunjukan bahwa PSAK 109, sistem pengendalian internal dan good  zakat governance sudah diterapkan dengan baik di BAZNAS kab/kota di Jawa Barat. Adapun faktor penghambat penerapannya; masih terdapat kendala dalam perolehan dana APBD dari pemerintah, sedikit pemahaman SDM mengenai penerapan PSAK 109 dan belum terlalu menerapkan nilai etika dalam bekerja. Selanjutnya, berdasarkan hasil uji hipotesis dan uji koefisien determinasi bahwa penerapan PSAK 109 dan penerapan sistem pengendalian internal mempunyai pengaruh signifikan terhadap good zakat governance. Ditunjukan dengan hasil koefisien determinasi sebesar 0,721 atau 72,1%, artinya kontribusi diterapkannya PSAK 109 dan sistem pengendalian internal terhadap;good zakat governance, cukup besar.Kata Kunci: PSAK109, Pengendalian Internal, Zakat, Good Governance
THE EFFECT OF WORKING CAPITAL TO TOTAL ASSET (WCTA) AND NET PROFIT MARGIN (NPM) ON THE RETURN STOCK OF PT ANEKA TAMBANG, TBK
Authors: Fahira Nur Ihsan , Hendra Endang
Published: February 2024

Investment is the placement of a number of funds or other resources carried out in the present to get future profits. Investors who invest in companies must know the factors that can cause profits or losses when investing. One of the factors that investors can consider to carry out investments is understanding financial statement information to determine the effectiveness of the company in generating the value of Working Capital to Total Assets (WCTA) or the company's ability to use the company's current assets, knowing the Net Profit Margin (NPM) to assess the company's ability to generate profits,  as well as knowing the level of profit on the capital invested in the investment or Stock Return. The results indicated that partial Working Capital to Total Assets (WCTA) had no significant effect on Stock Return with a coefficient of determination of 8.2%. Partially, Net Profit Margin had no significant effect on Stock Return with a coefficient of determination of 12.5%. Thus simultaneously, Working Capital to Total Assets (WCTA) and Net Profit Margin had no significant effect on Stock Return with a coefficient of determination of 25.3%.Keywords: Working Capital to Total Asset (WCTA), Net Profit Margin (NPM), Stock Rteurn
CORPORATE SOCIAL RESPONSIBILITY DISCLOSURE (CSRD) DAN FINANCIAL SLACK TERHADAP KINERJA KEUANGAN
Authors: Abdillah Pujangga , Regytha Aura Gunawan Szabyna Regytha x , Suprapti Suprapti , Suprayitno Adi
Published: February 2024

The objective of this study is to examine CSRD (Corporate Social Responsibility Disclosure) and financial slack affect financial performance. The state of the global industry continues to develop, making the company's business processes also develop. This economic progress is also accompanied by a decrease in environmental aspects with environmental damage in recent years. Disclosure of non-financial factors such as Corporate Social Responsibility (CSRD) indicators by companies aims to provide additional information about company performance that is not visible in annual report data or financial statements. The population of this study is the Indonesia Stock Exchange between 2020 to 2022. The sample of 768 observations was taken using a judgment sampling technique and quantitative approach. The findings of this study show that CSRD affects company performance as measured by Return on Assets (ROA). In other words, better CSRD standards can make companies perform better. The findings of this study also show that financial slack can improve company performance in the future.Keywords: Firm Performance, Financial Slack, CSRD
Geliat Gaya Hidup Halal Global: Peluang dan Tantangan
Authors: Mulyana Rijal Assidiq
Published: February 2024

The halal lifestyle is currently under scrutiny and experiencing massive growth not only in Indonesia but worldwide. It has evolved beyond being just a trend among contemporary societies to become a business and investment opportunity. The research is conducted through a qualitative approach, specifically a systematic literature review consisting of three stages: planning, conducting, and reporting. The research findings indicate that the halal lifestyle is not merely a modern way of living aligned with Islamic values but also has a futuristic dimension concerning the afterlife. It is expanding not only in Islamic countries or those with a Muslim majority but also in countries with Muslim minorities. The consumer base for the halal lifestyle is continuously growing, making it a promising investment and business opportunity. This growth is supported by seven key industries: halal food and beverage, Islamic fashion, Islamic media and recreation, Muslim-friendly tourism, halal pharmaceuticals, halal cosmetics, and the Islamic financial sector. However, the development of the halal lifestyle faces challenges, including: 1) Limited Islamic economic experts advising companies, 2) Not all products have halal labels, 3) Limited prevalence of halal certification, 4) Increasing Islamophobia in Europe and America, 5) Limited availability of halal raw materials, and 6) Narrow interpretation of halal, mainly focusing on food and beverages.
A Narrative Review of Pheochromocytoma in VHL
Authors: Coco Danilo , Leanza Silvana
Published: February 2024

This systematic review aims to investigate the clinical presentation, diagnostic methods, and management strategies for pheochromocytoma in patients with von Hippel-Lindau (VHL) disease, an autosomal dominant disorder that predisposes individuals to the development of various tumors, including pheochromocytomas. Pheochromocytoma is a rare neuroendocrine tumor of the adrenal medulla that occurs sporadically or as part of an inherited syndrome. The incidence of pheochromocytoma in VHL patients is estimated to be between 10–20%, making it the second most common tumor associated with VHL. Early detection and management of pheochromocytoma in VHL patients are critical for patient outcomes, as these tumors can cause severe hypertension, cardiovascular complications, and death. This review highlights the importance of screening for pheochromocytoma in VHL patients and discusses the current diagnostic and management strategies to optimize patient care.
Interaction of silica with polystyrene: mechanical properties, polymer/filler adhesion and failure behavior
Authors: Thomas Selvin P.
Published: February 2024

Composites of polystyrene with different loading of silica were prepared by melt mixing in a Brabender Plasticorder at a rotor speed of 60 rpm. The mechanical properties of the composites such as tensile behavior, impact strength, and flexural properties were studied as a function of filler loading. The tensile moduli of the composites increased with silica content. To improve adhesion between the filler and the matrix, an amino silane coupling agent was used. The composites with coupling agents showed enhanced mechanical properties. Thermal properties were measured using differential scanning calorimetry (DSC), thermogravimetry (TGA) and flammability tests. Composites with 15 wt.% and 0.5 wt.% coupling agent showed optimum properties. Scanning electron microscopy (SEM) studies of the tensile fractured samples revealed the extent of filler dispersion and filler/matrix interaction. Finally, experimental results were compared with theoretical predictions.
VISIÓN ANTROPOLÓGICA DE MARX SOBRE LA NATURALEZA FRENTE A LA ECOLOGÍA INTEGRAL DE LAUDATO SI’: UNA REVISIÓN SISTEMÁTICA
Authors: Quispe Fredy Tapia
Published: February 2024

En vista de la actual crisis ecológica mundial, caracterizada por una devastación del ambiente, resulta imprescindible realizar estudios críticos sobre su origen, estructura y desarrollo. La crisis, evidenciada en los altos niveles de contaminación y en una naturaleza explotada con creces, genera reflexiones de tipo académico. El presente estudio describe el pensamiento humanistaantropocéntrico de Karl Marx y el pensamiento humanista teocéntrico de la encíclica Laudato Si’ respecto a la naturaleza. Para ello se realizó una revisión sistemática de la literatura enmarcada en la metodología PRISMA. El registro consistió en la revisión de 250 documentos, período 2017-2023 en revistas indexadas en Scopus, Web of Sciencie (WoS), SciELO y Latindex, donde seevidenció que la naturaleza presentada en el Laudato Si’ está localizada en un escenario teológico mientras que en la antropología de Marx en un ámbito materialista; destacándose el llamado hecho por el papa Francisco para que se produzca un cambio, pues el problema social se ha ido transformando en netamente ambiental.
Relativistic Phenomena in the Chemistry of the Platinum Group Metals
Authors: Bond Geoffrey C.
Published: February 2024

It may at first sight seem strange that concepts developed by Albert Einstein in the first decade of the 20th century to explain the structure and dynamics of the cosmos should have any relevance to chemistry. However, it is now quite clear that the chemical behaviour of the heavier elements in particular is dominated by what are termed “relativistic effects”. This article explores the implications of this for the coordination and chemisorption of carbon monoxide and unsaturated hydrocarbons, and their reactions in homogeneous and heterogeneous catalysis involving the platinum group metals.
Metathesis Catalysed by the Platinum Group Metals
Authors: Dragutan V. , Dragutan I. , Balaban A. T.
Published: February 2024

The first two parts of this paper appeared in the April and July issues of this Journal. Part I looked at types of platinum group metals catalysts and metathesis activity and selectivity. Part II examined specific syntheses catalysed by these catalysts, in particular, reactions catalysed by ruthenium carbenes. This resulted in the syntheses of various carbocycles, heterocycles, metallacycles, crown ethers, polycyclic polymers, natural compounds and sub-units of biologically active compounds. The concluding part of this review deals first with acyclic diene metathesis and then with ring-opening metathesis polymerisations, and ranges of products formed by these reactions are given.
Single-Site Ruthenium Metathesis Catalysts
Authors: Dragutan V. , Dragutan I. , Balaban A. T
Published: February 2024

This paper presents an up-to-date investigation relating to the design and synthesis of the recently disclosed single-site ruthenium carbene metathesis catalysts. Created as a convenient counterpart of the earlier tungsten and molybdenum carbene catalysts, these novel ruthenium carbene complexes bear specific heterocyclic ligands and display comparable activity and selectivity in metathesis reactions, as well as good tolerance toward organic functionalities, air and moisture. Due to their unique properties, they can be successfully applied in numerous organic and polymer syntheses involving cross-metathesis, ring-opening and ring-closing metatheses, as well as ring-opening metathesis polymerisation. This paper updates our previous review on metathesis reactions published in this Journal last year.
Brittle Intercrystalline Fracture in Iridium
Authors: Panfilov Peter , Yermakov Alexander
Published: February 2024

Refractory iridium has a unique position among metals due to its resistance to corrosion and its inclination to brittle fracture, the latter only occurring under tension. Since 1960 iridium has been the subject of much research, but this has not lead to an understanding of its inclination to brittle fracture under load, although the problem of working iridium has been successfully solved. Grain boundary brittleness during mechanical treatment is the main problem with iridium, and is a continuing and important topic for academic discussion about iridium. Discussion of this problem, begun forty years ago, is continued here.
Palladium(+1) Carbonyl Clusters in the Catalytic Oxidation of Unsaturated Compounds
Authors: Stromnova Tatiana A.
Published: February 2024

Some palladium carbonyl clusters containing the palladium in the (+1) formal oxidation state, and derivatives of these clusters investigated in our laboratories are examined in this paper. In particular, letranuclear carbonyl carboxylates of palladium are discussed as a model of key intermediates in various processes, including CO oxidation by a palladium catalyst with molecular oxygen as the oxidant. A second type of cluster, a palladium cationic cluster which contains N-donor ligands acts as a catalyst precursor for processes such as exhaust gas purification. A third type of palladium carbonyl cluster includes bimetallic compounds which catalyse new reactions, such as the low-temperature dehydration of alcohols.
Catalysis by Gold/Platinum Group Metals
Authors: Thompson David T.
Published: February 2024

The recent surge of new interest in catalysis by gold (–) has led researchers to investigate the effects of adding other metals to the gold. As a result, there are a number of reactions with potential for industrial application where combinations of gold with a platinum group metal (pgm) have been shown to have advantages over either gold or the pgm alone. These findings are expected to lead to applications in chemical processing, pollution control and fuel cell applications. Here, a number of catalytic processes that have benefited from the synergy between a pgm and gold are described, and some interesting reports from recent conferences are highlighted.
The Manufacture of Hydrocyanic Acid by the Andrussow Process
Authors: Pirie J. M.
Published: February 2024

The manufacture of hydrocyanic acid by the catalytic combination of methane, ammonia and air has increased remarkably in recent years. Some of the features of this process, particularly the variety of platinum metal catalysts employed in it, are surveyed in this article.
Preparation of Heavy Water by Catalytic Exchange
Authors: Hawes M. G.
Published: February 2024

The great advantages of heavy water as a moderator in nuclear reactors have been very largely offset by the difficulties of establishing a satisfactory and economical manufacturing process. This article reviews possible methods of preparation by catalytic exchange, with particular reference to a process, recently developed in Germany, for the enrichment of heavy water by high pressure exchange between hydrogen and an aqueous platinum catalyst suspension.
The Platinum Metal Phthalocyanines
Authors: Keen I.M.
Published: February 2024

The likelihood that the platinum metal phthalocyanines might prove to be of commercial importance as homogeneous catalysts as well as of academic interest prompted an investigation into the preparation of these compounds and their subsequent characterisation.
The Wetting of Platinum and Its Alloys by Glass
Authors: Selman G. L. , Spender M. R. , Darling A. S.
Published: February 2024

In the second part of this paper it is shown that rhodium-platinum alloys are less readily wetted by glass than pure platinum, although the effect is marginal and disappears at temperatures above 1200°C. Gold additions are shown to increase the resistance to wetting much more effectively, the equilibrium contact angle between borosilicate glass and platinum containing 5 to 7 per cent of gold and 10 per cent of rhodium remaining above 75° up to 1500°C. This ternary alloy is stronger and more resistant to creep at high temperatures than the binary 10 per cent rhodium-platinum alloy.
The Platinum Metals and Their Alloys
Authors: Hume-Rothery W.
Published: February 2024

In this paper the electronic structures of the elements of Group VIII of the Periodic Table are outlined, and the difference between the platinum metals and other metals in the group is emphasised. The constitution of the alloys of the platinum metals with silver and gold is then discussed, and an interpretation is offered. The alloying behaviour of the platinum metals with a number of transition metals is interpreted in terms of some recently established electron concentration principles.
Evaluation of Supported Catalysts for Liquid Phase Reactions
Authors: Acres G. J. K. , Bond G. C.
Published: February 2024

Sufficient information is now available to lead the intending user of a supported noble metal catalyst to that combination of metal and support most likely to catalyse the reaction he desires to perform. However, each combination can be prepared by a number of different techniques, and the resulting catalysts need to be evaluated since their performance in the desired reaction will depend on a number of factors that are still only poorly understood. The purpose of this article is to describe some of the precautions which need to be observed in evaluating catalysts for liquid-phase reactions.
One Hundred and Fifty Years
Authors: McDonald Donald
Published: February 2024

Since its inception a century and a half ago the firm of Johnson Matthey has played a leading part in the extraction, refining and supply of platinum and its allied metals. To mark this anniversary, Mr McDonald has prepared a full account of the growth of these activities from the days when Percival Norton Johnson established his business, through the early years when the uses of platinum were virtually confined to the laboratory, and on to more recent times when industrial applications are of major importance. In this article the ebb and flow of demand and supply are clearly traced, with Johnson Matthey growing steadily to its present dominant position, jointly with Rustenburg Platinum Mines, as the world’s largest supplier of the platinum metals
Radiochemical Methods in the Study of Platinum Metal Catalysis
Authors: Thomson S. J. , Webb G.
Published: February 2024

Because of their extreme sensitivity, radiochemical methods are of great help in the study of catalytic processes. Changes at a surface at concentrations less than those required to yield monolayer coverage can readily be detected without interrupting the system for analysis. This article describes the application of such methods to the determination of metal areas and of catalytically active areas in supported metal catalysts and also reviews their usefulness in the study of electrocatalysis and in the unravelling of catalytic reaction mechanisms.
Sliding Noble Metal Contacts
Authors: Darling, A. S. , Selman G. L.
Published: February 2024

When, as in many low torque potentiometers, contact pressures must not exceed a few grams the use of noble metals for both resistance wire and wiping contact becomes almost essential. As the factors that determine the electrical and mechanical behaviour of such low load sliding contacts have not yet been established, wiper/slidewire combinations are still selected on an empirical basis. This paper, based on a lecture recently delivered to the Fourth International Research Symposium on Electrical Contact Phenomena at Swansea, describes some results obtained on an apparatus in which the abrasion resistance and frictional characteristics of precision resistance alloys can be assessed in an objective manner at very low contact loads. Under such conditions metal is transferred from wiper to resistance alloy and the efficiency of this transfer process determines the electrical behaviour of these sliding contacts.
Platinum Metal Contacts
Authors: J. C. C.
Published: February 2024

Platinum metals and their alloys featured in many of the fifty papers presented at the Fourth International Symposium, sponsored jointly by the Institute of Physics and the Physical Society and the Institution of Electrical Engineers, held in July at the University College of Swansea.
Nitrosyl Complexes of the Platinum Metals
Authors: Cleare, M. J.
Published: February 2024

In recent years much research has been carried out on platinum group metal complexes, especially those containing the carbonyl ligand. As the nitrosyl group is a nitrogen bonded ligand which in its normal mode of bonding is isoelectronic with carbon monoxide, the chemistry of complexes containing co-ordinated nitric oxide is interesting, and they may have similar potential uses to the carbonyl complexes. This article outlines our present knowledge of the nitrosyl complexes and their mode of bonding.
Making Corrosion-Resistant Brazed Joints in Stainless Steel
Authors: Sloboda M. H.
Published: February 2024

Stainless steel parts brazed with standard low-melting brazing alloys are susceptible to a specific kind of corrosion by water or humid atmosphere, generally known as interface or crevice corrosion. One of the advantages of brazing alloys of the silver-copper-palladium type is that they will produce joints in stainless steel resistant to this form of failure.
Homogeneous Catalysis by Some Ruthenium and Rhodium Complexes
Authors: Webster David E. , Wells Peter B.
Published: February 2024

One of the most important applications for organometallic compounds is likely to be their use as homogeneous catalysts in the industrial production of organic chemicals. The majority of these catalysts will undoubtedly be complexes of the platinum metals. This article focuses attention on the problems associated with the production and characterisation of catalytically active species formed in solutions of a number of rhodium and ruthenium complexes. Factors determining activity are described and a suggested formulation for an active species is presented.
Availability of the Platinum Metals
Authors: Hunt L. B. , Lever F. M.
Published: February 2024

Increasing industrial uses of platinum and its associated metals – palladium, rhodium, ruthenium, iridium and osmium – have occasionally given rise to doubts as to the future availability of adequate supplies. This has sometimes discouraged research workers from considering the advantages of these metals in their search for new routes or for new products in the chemical and allied industries. This paper, presented at the Symposium on the Platinum Group Metals organised by the American Chemical Society during its meeting in New York in September, outlines the very substantial productive resources now associated with these metals and relates them to the trends in their applications in industry.
Platinum and the Refractory Oxides
Authors: Darling A. S. , Selman G. L. , Rushforth R.
Published: February 2024

The reactions between platinum and the refractory materials in contact with it, described in earlier articles in this series, account for many of the thermocouple failures that occur under practical industrial conditions. Reducing atmospheres accentuate such tendencies, although several factors usually cooperate to cause complete failure. This article examines the way in which platinum:rhodium-platinum thermocouples behave in service under both oxidising and reducing conditions and also in vacuum furnaces.
The Form of the Interaction between Palladium and Hydrogen
Authors: Burch R. , Lewis F. A.
Published: February 2024

The high diffusibility of hydrogen in solid phases of the palladium-hydrogen system allows thermodynamic equilibrium to be established over a wide range of experimental conditions. Evidence has long existed that, in the hydride phases formed, the hydrogen:palladium ratio is not simple and is a function of equilibrium pressure and of temperature. Theoretical models of the system have often centred on modifications of the palladium electron band structure due to hydrogen absorption but increasing attention has been paid to the consequences of lattice strain. The position is now reviewed in the light of recent work.
The Control of Air Pollution
Authors: Acres G. J. K.
Published: February 2024

Honeycat catalyst systems have been successfully evaluated and used in a wide range of industrial processes that emit organic fumes and odours. These include wire enamelling, paint baking, phthalic anhydride manufacture, paper coating, and nitric acid manufacture. More recently the system has been successfully evaluated for the removal of odours from the animal, fish and food processing industries.
Automobile Emission Control Systems
Authors: Acres G. J. K. , Cooper B. J.
Published: February 2024

Stringent regulations governing automobile exhaust emissions are due to come into force in the United States. Johnson Matthey have undertaken the development of platinum-based catalytic reactors for control of these exhaust emissions. Two new types of catalyst have demonstrated the feasibility of exhaust control by catalytic means, and have been incorporated on test vehicles to achieve emission levels well below the specified levels for 1975 and 1976 model year cars. Extended road mileage on the former system has shown that good durability can be obtained, with emissions below 1975 limits for 25,000 miles.
The Fluorine Compounds of the Platinum Metals
Authors: Holloway John H.
Published: February 2024

This review summarises some of the chemistry of the platinum metal fluorides and outlines the part they have played in developments in inorganic chemistry. A number of new compounds in this field have been identified only recently for the first time.
Ordering in Platinum Group Metal Alloys
Authors: Irani R. S.
Published: February 2024

The ordering of the interesting family of alloys based on the platinum group metals has been hitherto somewhat neglected, partly due to problems of specimen preparation. Techniques used in metallographic studies on these alloys are described. Understanding of the properties of these alloys may lead to wider practical applications of them.
Coating Methods for Use with the Platinum Metals
Authors: Hood Christopher
Published: February 2024

The economic use of platinum group metal coatings requires that the most appropriate coating method should be used for any particular application. This article reviews the techniques available for various substrate materials and outlines some of the more important properties obtained with different types of deposit.
Carboxylato Complexes of the Platinum Group Metals
Authors: Dobson Alan , Robinson Stephen D.
Published: February 2024

The recent rapid growth of interest in the carboxylato complexes of the platinum group metals has led to many significant advances. This article describes some of the more important chemical, structural and catalytic properties displayed by this class of compound.
Preparation of Alumina Supported Palladium-Platinum Catalyst
Authors: Yamaguchi S.
Published: February 2024

Economic considerations require that platinum metals and alloys used as catalysts should have a high surface to volume ratio, thus extremely small particles are required. This article describes a tribophysical process for producing such particles uniformly dispersed on alumina. The catalytic activity and life of the materials produced have been tested for the oxidation of hydrocarbon gas and the results are discussed.
Platinum in the Decoration of Porcelain and Pottery
Authors: Hunt L. B.
Published: February 2024

The early researches on platinum carried out by a number of distinguished European chemists were virtually contemporary with the first scientific studies of porcelain and its decoration. The author traces the sequence of these investigations leading to the application of platinum to provide a brilliant and permanent metallic lustre to porcelain and later to the less expensive earthenware.
Intermetallic Compounds of the Platinum Group Metals
Authors: McGill I. R.
Published: February 2024

Many of the platinum group intermetallic compounds possess unique properties which may occur in most interesting combinations. This paper draws attention to a number of these and briefly describes some applications for them. It suggests that further study is required before a full appreciation can be made of their perhaps considerable potential for use in hostile environments.
The State of the Metal Phase in Supported Platinum-Containing Bimetallic Catalysts
Authors: Charcosset Henri
Published: February 2024

The catalytic reforming of crude oils has been considerably improved during the last ten years by the addition of a second metal, generally rhenium or iridium, to the small amounts of platinum present in alumina supported catalysts. A most important question, from a scientific point of view, is to differentiate between the various possible states of the metal phase, which may range from a mixture of platinum and the second metal particles to homogeneous bimetallic aggregates. This differentiation is extremely difficult because of the very small size of the metallic particles. It is reported that hydrogen-oxygen titration provides evidence of the presence of small particles of pure rhenium, iridium or ruthenium in platinum bimetallic alumina supported catalysts.
Research on Single Crystals of Some Platinum Group Metals
Authors: Savitskii E. M. , Polyakova V. P. , Gorina N. B.
Published: February 2024

The microstructure and some physical and chemical properties of the platinum group metals iridium, rhodium, ruthenium and osmium, prepared by electron-beam melting, have been investigated and the results are reviewed in this article. The degree of anisotropy of these properties has been evaluated and high plasticity has been demonstrated for single crystals of the refractory platinum group metals.
Platinum Metal Cluster Carbonyls and Their Metal Surface Analogues
Authors: Woolley R. G.
Published: February 2024

This article describes some of the experimental evidence that suggests a useful analogy can be made between the transition metal cluster carbonyls and the corresponding carbon monoxide-metal chemisorption systems. This analogy is interpreted using recent electronic structure results in metal physics, leading to a theoretical framework in which cluster chemistry can be approached.
Alloys of Platinum and Tungsten
Authors: Knapton A. G.
Published: February 2024

The availability of a complete and accurate phase diagram is an essential requirement if a full understanding of the properties, and hence the potential applications, of an alloy system is to be gained. Although the general nature of the tungsten-platinum constitutional diagram has been known for many years, it is now apparent that intermediate phases which are not incorporated in the published phase diagrams may exist, and evidence to support this is presented.