Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Ann Sci ; 75(4): 330-360, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30481124

RESUMO

Diffraction gratings are famously associated with Henry Rowland of Johns Hopkins University but there were precursors. Although gratings were first made and used in Europe, reliable machines for ruling gratings were developed in the USA, and two men, Lewis Rutherfurd and William Rogers, tackled the problem before Rowland. Rutherfurd, a wealthy independent astronomer, designed and built the first screw-operated engine for ruling diffraction gratings, the fore-runner of almost all subsequent ruling engines. With it he and his assistant D. C. Chapman ruled many gratings which he generously distributed to practising scientists, thereby materially advancing the science of spectroscopy. Rogers was a Harvard astronomer who developed an interest in the ruling of fine lines on glass that led him to construct a ruling engine with which he investigated the causes of the errors in the rulings he had examined. He continued to seek improvements with a second engine designed for ruling diffraction gratings. He ceased developing this engine when Rowland's excellent gratings began to be available, concentrating instead on related problems to which he could apply the knowledge and skills he had gained, but his investigations assisted Rowland and other later ruling engine builders. This paper brings together what is known about the ruling engines of Rutherfurd and Rogers, their development, the gratings they produced, their quality and the work that was done with them, and assesses and compares their achievements and the impacts of the work of these two men.


Assuntos
Óptica e Fotônica/instrumentação , Análise Espectral/instrumentação , Desenho de Equipamento , Europa (Continente) , História do Século XIX , Luz , Óptica e Fotônica/história , Óptica e Fotônica/métodos , Análise Espectral/história , Análise Espectral/métodos , Estados Unidos
2.
Postepy Biochem ; 61(3): 284-91, 2015.
Artigo em Polonês | MEDLINE | ID: mdl-26677575

RESUMO

Chemically modified analogues of nucleosides and nucleotides, have been thoroughly investigated since the discovery of DNA double helix by Watson and Crick in 1953 (Nature 171: 737). Chemical structures, first of all tautomerism, of the nucleic acid bases, as well as the conformations of the nucleic acids constituents, determine the secondary and tertiary structures of DNA and RNA polymers. Similarly, structural and dynamic parameters of nucleoside derivatives determine their biological activity in mutagenesis, neoplastic transformation, as well as antiviral or anticancer properties. In this review, a multidisciplinary approach of Prof. David Shugar's group is presented in the studies on nucleosides and nucleotides. It consists in chemical syntheses of suitable analogues, measurements of physicochemical and spectral parameters, conformational analysis by means of nuclear magnetic resonance (NMR) and X-ray diffraction, as well as characteristics of the nucleoside analogues as inhibitors of some selected, target enzymes, crucial in respect to antiviral activity of the analogues. These long-lasting studies follows upon the line of the main paradigm of molecular biophysics, i. e. structure-activity relationship.


Assuntos
Antivirais/história , Bioquímica/história , Nucleosídeos/história , Nucleotídeos/história , Antivirais/química , Antivirais/uso terapêutico , História do Século XX , História do Século XXI , Conformação Molecular , Nucleosídeos/síntese química , Nucleosídeos/química , Nucleosídeos/uso terapêutico , Nucleotídeos/síntese química , Nucleotídeos/química , Nucleotídeos/uso terapêutico , Polônia , Análise Espectral/história
4.
Ann Sci ; 72(1): 28-74, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26104088

RESUMO

Diffraction gratings have contributed enormously to modern science. Although some historians have written about them, there is much more to be brought to light. This paper discusses their development and use in the period up to about 1880 before Rowland began to produce them. Rittenhouse described the action of a diffraction grating in 1786, but no explanation was possible until the wave theory of light was developed. Fraunhofer discovered the dark lines in the solar spectrum in 1814, and then investigated diffraction, producing the first ruled gratings, making detailed measurements and calculating the wavelengths of prominent spectral lines. After Bunsen and Kirchhoff showed the association between spectral lines and chemical elements there was an upsurge of interest in measuring wavelengths. The gratings used in this work almost all came from one source, a relatively unknown instrument maker called Nobert, who made them by an extremely laborious process using a machine he had built himself. The most significant wavelength measurements were made by Ångström, but Mascart, Van der Willigen, Stefan, Ditscheiner and Cornu also did important work. Nobert gratings were investigated by Quincke, copied photographically by Rayleigh, and were known and discussed in the USA. Nobert's work helped to advance spectroscopy much more than has been acknowledged.


Assuntos
Luz , Física/história , Espalhamento de Radiação , Análise Espectral/história , Europa (Continente) , História do Século XVIII , História do Século XIX , Física/instrumentação , Análise Espectral/instrumentação
8.
Biotech Histochem ; 87(4): 288-94, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22148999

RESUMO

Raphael Meldola (1849-1915), English industrial and academic chemist, spectroscopist, naturalist, educator and lobbyist for science, is today almost a forgotten scientist whose life is celebrated only with a medal awarded by the Royal Society of Chemistry that honors achievement by younger chemists. In the 1870-80s, however, he invented a number of important synthetic dyestuffs including the cotton dyes isamine blue and Meldola's blue, and also naphthol green B, all of which have had application in biology and medicine. I describe here the early emergence of the synthetic dye industry, the first science-based industry, Meldola's role in its development, and his own inventions. Meldola's wide ranging achievements in science led to appointments as president of important professional scientific and manufacturers' societies. He was a fervent disciple of natural selection, a correspondent of Charles Darwin, and a prominent 19(th)-century neo-Darwinian. In 1886, drawing on analogies with evolutionary theory, he warned the British that neglect of science, particularly chemistry, would lead to industrial decline and even extinction, though his message generally was ignored, at least until 1914.


Assuntos
Compostos Cromogênicos/química , Análise Espectral , História do Século XIX , História do Século XX , Análise Espectral/história , Análise Espectral/tendências
9.
Neuroimage ; 62(2): 693-8, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22001263

RESUMO

The article embraces two periods in the history of fMRI starting with our early work on functional spectroscopy leading to the detection of the ominous initial dip and our recent development of gradient-less imaging based on the principles of MR-encephalography (MREG). In addition to presenting examples from these two periods the article tries to convey the spirit and inspiration behind these developments.


Assuntos
Mapeamento Encefálico/história , Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/história , Imageamento por Ressonância Magnética/métodos , Encéfalo/fisiologia , História do Século XX , História do Século XXI , Processamento de Imagem Assistida por Computador/métodos , Análise Espectral/história , Análise Espectral/métodos
12.
Faraday Discuss ; 150: 9-22; discussion 113-60, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22457941

RESUMO

Since the serendipitous discovery of the Fraunhofer spectrum in the Sun in 1814 which initiated spectroscopy and astrophysics, spectroscopy developed hand in hand with astronomy. I discuss my own work on the infrared spectrum of H3+ from its discovery in the laboratory in 1980, in interstellar space in 1996, to recent studies in the Galactic center as an example of astronomical spectroscopy. Its spin-off, the spectroscopy of simple molecular ions, is also briefly discussed.


Assuntos
Astronomia/métodos , Íons/química , Prótons , Análise Espectral/métodos , Trítio/química , Astronomia/história , Poeira Cósmica/análise , Galáxias/química , História do Século XX , História do Século XXI , Humanos , Análise Espectral/história
14.
Photosynth Res ; 103(1): 1-6, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19924560

RESUMO

Mike Wasielewski's pioneering work on Photosystem II photochemistry has an important place in the history of photosynthesis; we are proud to have been associated with him in making those first measurements. Here, we present our association and publications with him, and provide some of the history behind this research.


Assuntos
Botânica/história , Fotossíntese/fisiologia , Complexo de Proteínas do Centro de Reação Fotossintética/história , História do Século XX , Oxigênio/metabolismo , Complexo de Proteínas do Centro de Reação Fotossintética/fisiologia , Análise Espectral/história , Análise Espectral/métodos
15.
J Med Biogr ; 16(4): 237-40, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18953000

RESUMO

Dr William Allen Miller developed an early interest in science and astronomy at secondary school. Although qualifying in medicine, he pursued a career in Chemistry at King's College, London. A particular interest in spectrum analysis led to a collaboration with Dr Huggins in examining the spectra of stars. For this work they each received the Gold Medal of the Royal Astronomical Society. His subsequent work at King's College, the Royal Society, the Courts of Law and for various Government enterprises earned him an outstanding scientific and advisory reputation.


Assuntos
Astronomia/história , Química/história , Análise Espectral/história , Pesquisa Biomédica/história , Docentes/história , História do Século XIX , Reino Unido
17.
J Mol Graph Model ; 26(3): 596-601, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17482855

RESUMO

The path from diatomic molecule spectroscopy to molecular modelling and drug discovery is described, along with aspects of the commercialisation of research. It is a history tightly coupled with the advances in computers over the past 50 years, but with a future full of opportunity.


Assuntos
Simulação por Computador/história , Desenho de Fármacos , Modelos Moleculares , Análise Espectral/história , História do Século XX , História do Século XXI
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...