Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 75.377
Filtrar
2.
Ambix ; 71(2): 209-224, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38577772

RESUMEN

During the eighteenth century, authors of chemical treatises and courses on chemistry often introduced their work with a chapter devoted to the history of chemistry. While there may have been different reasons for the use of history, its importance was never seriously questioned. However, when Antoine Laurent Lavoisier (1743-1794) took a professional interest in chemistry in the early 1770s, he progressively became uneasy with this literary tradition. In this essay, I intend to explore the ways in which Lavoisier looked at the history of chemistry and to show how, from the 1780s onwards, he began to adopt a hostile attitude towards historical erudition. This vision, which culminated in the publication of the Traité élémentaire de chimie (Paris, 1789), was not only the result of a stylistic preference but constituted a direct attack on a way of doing chemistry from which Lavoisier intended to distance himself.


Asunto(s)
Química , Historia del Siglo XVIII , Química/historia , Francia
3.
Cell Chem Biol ; 31(3): 380-382, 2024 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-38518743

RESUMEN

Bioorthogonal chemistry was deservedly recognized with the 2022 Nobel Prize in Chemistry, having transformed the way chemists and biologists interrogate biological systems in the past twenty years. This Voices piece asks researchers from a range of backgrounds: what are some major challenges and opportunities facing the field in coming years?


Asunto(s)
Premio Nobel , Química
4.
Ambix ; 71(1): 139-140, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38275132

Asunto(s)
Alquimia , Sociedades , Química
5.
Acta Pharm ; 73(4): 735-753, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-38147476

RESUMEN

The chemical science community will commemorate the 155th anniversary of Mendeleev's groundbreaking discovery of the periodic table of elements in 2024. This paper aims to underscore the significance of Mendeleev's honorary membership in the Academy of Sciences in Zagreb, Croatia, which occurred in 1882, making it the first scientific academy in Europe to extend this recognition. Additionally, we seek to explore the contextual circumstances that contributed to this noteworthy event within the broader European context. To provide insight into the specificities and variations in the influence and reception of the periodic table of elements within the educational process of select European countries (Russia, Germany, Czech Lands, Serbia), we conducted a comprehensive review, drawing comparisons to Croatia. Notably, upon its initial publication in 1869, the discovery of the periodic table did not gain immediate acceptance in Croatia, largely attributed to the absence of a well-established presence of chemical science within the country. About fifteen years passed from Mendeleev's discovery of the periodic law to its reception and dissemination throughout Croatia. Despite an initial delay, Croatian chemical science followed the development of the periodic table through secondary and university education, while actively partaking it in.


Asunto(s)
Química , Croacia , Química/educación , Elementos Químicos , Europa Oriental
6.
Actual. nutr ; 24(4): 240-246, Oct-Dic. 2023.
Artículo en Español | LILACS | ID: biblio-1531394

RESUMEN

Introducción: Se considera a la carne de guanaco y sus derivados un producto cárnico consumible (Art. 261, CAA). El objetivo fue evaluar los aspectos nutricionales en cortes de uso comercial (lomo y peceto) de la carne de guanaco (Lama guanicoe guanicoe), del departamento Escalante (Chubut, Argentina) durante los años 2022 y 2023. Materiales y métodos: Se obtuvieron las muestras de 10 ejemplares machos adultos. Se determinó humedad (AOAC 950.46), proteínas (AOAC 928.08), grasas totales (AOAC 960.39), cenizas (AOAC 920.153), carbohidratos (cálculo por diferencia) y colesterol (Wiener lab®). Resultados: La composición centesimal de lomo y peceto, expresada en g/100 g en base húmeda, y el contenido de colesterol, expresado en mg/100 g en base húmeda, para el año 2022, en animales faenados en la estancia La Paulina, fue: humedad 75,1±0,13 y 5,2±0,06; proteínas 22,2±0,23 y 22,3±0,18; grasas totales 0,69±0,01 y 0,68±0,02; cenizas 0,85±0,03 y 0,88±0,04; carbohidratos 1,14 y 0,95; y colesterol 58,9±4,52 y 64,4±4,20, respectivamente. No se observaron diferencias estadísticas entre la composición de ambos cortes (p>0,05). La composición centesimal de lomo y peceto, expresada en g/100 g en base húmeda, y el contenido de colesterol, expresado en mg/100 g en base húmeda, para el año 2023 fue: humedad 76,6±0,14 y 76,7±0,17; proteínas 20,6±0,21 y 20,5±0,25; grasas totales 0,58±0,03 y 0,53±0,03; cenizas 1,07±0,04 y 1,02±0,02; carbohidratos 1,21 y 1,19; y colesterol 43,5±3,17 y 37,8±2,10, respectivamente. Se observó un mayor contenido de grasa en el corte lomo (p<0,05), mientras que no se observaron diferencias estadísticas (p>0,05) para el resto de los nutrientes. Conclusiones: El guanaco es una especie abundante y silvestre, muy atractiva para el consumo humano por sus cualidades nutritivas. Este alimento autóctono representa una opción alimentaria regional, con un potencial posicionamiento en el mercado nacional e internacional como una carne exótica. La carne de guanaco presenta un contenido de proteínas ligeramente mayor, un porcentaje de grasas totales significativamente menor y un nivel de colesterol ligeramente inferior, respecto a otras carnes rojas de consumo habitual


Introduction: Guanaco meat and its derivatives are considered a consumable meat product (Art. 261, CAA). The objective was to evaluate the nutritional aspects of commercially used cuts (loin and round) of guanaco meat (Lama guanicoe guanicoe) from the Escalante department (Chubut, Argentina) during the years 2022 and 2023. Materials and Methods: Samples were obtained from 10 adult male specimens. Moisture (AOAC 950.46), protein (AOAC 928.08), total fat (AOAC 960.39), ash (AOAC 920.153), carbohydrates (calculated by difference), and cholesterol (Wiener lab®) were determined. Results: The proximate composition of loin and round, expressed as g/100 g on a wet weight basis, and the cholesterol content, expressed as mg/100 g on a wet weight basis, for the year 2022, in animals slaughtered at La Paulina ranch, was as follows: moisture 75.1±0.13 and 75.2±0.06; protein 22.2±0.23 and 22.3±0.18; total fat 0.69±0.01 and 0.68±0.02; ash 0.85±0.03 and 0.88±0.04; carbohydrates 1.14 and 0.95; and cholesterol 58.9±4.52 and 64.4±4.20, respectively. No statistical differences were observed between the composition of both cuts (p>0.05). The proximate composition of loin and round, expressed as g/100 g on a wet weight basis, and the cholesterol content, expressed as mg/100 g on a wet weight basis, for the year 2023 was as follows: moisture 76.6±0.14 and 76.7±0.17; protein 20.6±0.21 and 20.5±0.25; total fat 0.58±0.03 and 0.53±0.03; ash 1.07±0.04 and 1.02±0.02; carbohydrates 1.21 and 1.19; and cholesterol 43.5±3.17 and 37.8±2.10, respectively. A higher fat content was observed in the loin cut (p<0.05), while no statistically significant differences were observed (p>0.05) for the rest of the nutrients. Conclusions: The guanaco is an abundant and wild species, highly attractive for human consumption due to its nutritional qualities. This native food represents a regional dietary option, with potential positioning in the national and international markets as an exotic meat. Guanaco meat has a slightly higher protein content, significantly lower total fat percentage, and a slightly lower cholesterol level compared to other commonly consumed red meats


Asunto(s)
Camélidos del Nuevo Mundo , Química , Nutrición, Alimentación y Dieta
8.
ACS Chem Biol ; 18(10): 2097-2100, 2023 10 20.
Artículo en Inglés | MEDLINE | ID: mdl-37814995

RESUMEN

Prof. Chuan He was awarded the Tetrahedron Prize this year, one of the world's most prestigious prizes in organic chemistry. This In Focus briefly delves into the remarkable work of Prof. Chuan He and explores how his recent accolades underscore his impact on the world of science. His seminal contributions have paved the way for new directions at the interface of organic chemistry and life sciences.


Asunto(s)
Distinciones y Premios , Química
11.
Ambix ; 70(4): 337-356, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37698131

RESUMEN

The materials and practices of chymical procedures have become key sources of information among science historians, opening up channels for cross-disciplinary dialogue. This is especially true with regard to material culture-based disciplines such as archaeology whose bottom-up approach offers significant contributions to the new historiography of science. Parallel to this trend, some archaeological scientists who specialise in reconstructing past technologies have begun to address questions concerning the production and circulation of scientific knowledge, and have focused as well on the contributions of artists/artisans to the development of natural philosophical theories. This essay charts the history of this archaeology of alchemy and chemistry and its development as a sub-discipline of archaeological science. By mapping this history, from an initial period with a focus on metallurgy to current trends, it demonstrates how the archaeology of alchemy and chemistry both mirrors and, at the same time, feeds the broadening scope of the historiography of science. After surveying the most relevant works and highlighting the key contributions that archaeologists have brought to a discourse related to the creation of scientific knowledge, the essay also offers a series of ideas related to materials awaiting comprehensive study that will further strengthen methodological synergies across disciplines.


Asunto(s)
Alquimia , Arte , Historiografía , Arqueología , Tecnología , Química
12.
Chemistry ; 29(66): e202302400, 2023 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-37646539

RESUMEN

Studies into the biology of condensed phosphates almost exclusively cover linear polyphosphates. However, there is evidence for the presence of cyclic polyphosphates (metaphosphates) in organisms and for enzymatic digestion of branched phosphates (ultraphosphates) with alkaline phosphatase. Further research of non-linear condensed phosphates in biology would profit from interactome data of such molecules, however, their stability in biological media is limited. Here we present syntheses of modified, non-hydrolysable analogues of cyclic and branched condensed phosphates, called meta- and ultraphosphonates, and their application in a chemical proteomics approach using yeast cell extracts. We identify putative interactors with overlapping hits for structurally related capture compounds underlining the quality of our results. The datasets serve as starting point to study the biological relevance and functions of meta- and ultraphosphates. In addition, we examine the reactivity of meta- and ultraphosphonates with implications for their "hydrolysable" analogues: Efforts to increase the ring-sizes of meta- or cyclic ultraphosphonates revealed a strong preference to form trimetaphosphate-analogue structures by cyclization and/or ring-contraction. Using carbodiimides for condensation, the so far inaccessible dianhydro product of ultraphosphonate, corresponding to P4 O11 2- , was selectively obtained and then ring-opened by different nucleophiles yielding modified cyclic ultraphosphonates.


Asunto(s)
Fosfatos , Proteómica , Fosfatos/química , Polifosfatos/química , Química
16.
ACS Chem Biol ; 18(4): 671-673, 2023 04 21.
Artículo en Inglés | MEDLINE | ID: mdl-36971654

RESUMEN

On February 7th, 2023, the Wolf Foundation (www.wolffund.org.il/) announced that the Wolf Prize in Chemistry was awarded to three distinguished scholars, Prof. Chuan He from The University of Chicago, Prof. Hiroaki Suga from The University of Tokyo, and Prof. Jeffery W. Kelly from The Scripps Research Institute, "for pioneering discoveries that illuminate the functions and pathological dysfunctions of RNA and proteins and for creating strategies to harness the capabilities of these biopolymers in new ways to ameliorate human diseases." Their pioneering research works have made a huge impact on contemporary chemical biology and deserve celebration by the whole community.


Asunto(s)
Distinciones y Premios , Química , Animales , Humanos , Masculino , Biología , Historia del Siglo XX , Proteínas
17.
Med Sci (Paris) ; 39(2): 184-186, 2023 Feb.
Artículo en Francés | MEDLINE | ID: mdl-36799757

RESUMEN

Title: Prix Nobel de chimie 2022 - La chimie click et la chimie bio-orthogonale. Abstract: Selon Sydney Brenner, lauréat du prix Nobel de physiologie ou médecine en 2002, « les progrès de la science dépendent de nouvelles techniques, de nouvelles découvertes et de nouvelles idées, probablement dans cet ordre ¼. Le prix Nobel de chimie 2022 a été décerné à Carolyn Ruth Bertozzi (université de Stanford, États-Unis), Morten Peter Meldal (université de Copenhague, Danemark), et Karl Barry Sharpless (institut de recherche Scripps, La Jolla, États-Unis) pour le développement de la chimie click et de la chimie bio-orthogonale. Ce prix Nobel récompense dans une large mesure un développement conceptuel dans les techniques de synthèse chimique et de marquages des cellules, mais également des nouvelles découvertes, notamment en cancérologie. Morten Meldal et Barry Sharpless (qui obtient maintenant son deuxième prix Nobel de chimie, après celui de 2001 pour ses travaux sur la catalyse chirale de réactions d'oxydation) ont développé la chimie click, qui permet d'assembler des briques moléculaires rapidement et efficacement. Carolyn Bertozzi, quant à elle, a porté la chimie click à un autre niveau, en permettant son utilisation biologique sur des cellules et même chez l'animal in vivo.


Asunto(s)
Química Clic , Premio Nobel , Humanos , Química
18.
Anal Bioanal Chem ; 415(4): 527-532, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36602567

RESUMEN

The 2022 Nobel Prize in Chemistry recognized the development of biorthogonal chemical ligation reactions known as click chemistry in biomedicine. This concept has catalyzed significant progress in sensing and diagnosis, chemical biology, materials chemistry, and drug discovery and delivery. In proteomics, the ability to incorporate a click tag into proteins has propelled development of powerful new methods for selective enrichment of protein complexes that inform understanding of protein networks. It also has had a strong influence on the ability to enrich for protein post-translational modifications. This feature article summarizes the impacts of biorthogonal click chemistry on proteomics.


Asunto(s)
Química Clic , Premio Nobel , Química Clic/métodos , Proteínas , Procesamiento Proteico-Postraduccional , Proteómica/métodos , Química
19.
F1000Res ; 12: 589, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38778813

RESUMEN

Background: Chemistry is viewed as a difficult and challenging subject by many learners and teachers which leads to poor academic performance in the subject. The majority of the pre-service science teachers in Zimbabwean teachers' colleges also find Chemistry to be a challenging subject. The focus of this study was to simplify and contextualize the teaching and learning of Chemistry concepts for life-long survival and problem-solving skills through exploring the influence of indigenous Chemistry knowledge on Chemistry metacognition. Methods: An embedded mixed methods case study was underpinned by the social constructivist theory, which is used to collect and analyse the data. Twenty-nine respondents were purposively sampled. Their metacognition awareness was determined through focus group interviews which are triangulated with a paper and pen test. The indigenous Chemistry knowledge possessed by the pre-service science teachers was collected using focus group interviews, which was then used in the intervention stage for Chemistry metacognition. Results: The findings suggest that indigenous knowledge influences chemistry metacognition in a positive way. Conclusions: Further research is required on the relationship between indigenous Chemistry knowledge and Chemistry metacognition. It is recommended that Chemistry educators should be capacitated with skills for identifying and applying indigenous Chemistry knowledge that is relevant to Chemistry metacognition.


Asunto(s)
Química , Metacognición , Humanos , Química/educación , Conocimiento , Femenino , Masculino , Grupos Focales , Pueblos Indígenas/psicología , Adulto
20.
Sci Bull (Beijing) ; 67(6): 561-564, 2022 03 30.
Artículo en Inglés | MEDLINE | ID: mdl-36546114

Asunto(s)
Química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA