Naphthopyran Dyes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Andrew Towns

AbstractThis article covers the most commercially important type of photochromic dye. It outlines which of its subclasses are of most use and how they are manufactured. The history of the industrial exploitation of this kind of colorant is briefly given before illustrating its versatility with examples of the most useful ways in which photochromic properties can be manipulated by making adjustments to molecular structure.

Biology ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 394
Author(s):  
Elmira I. Yakupova ◽  
Liya G. Bobyleva ◽  
Sergey A. Shumeyko ◽  
Ivan M. Vikhlyantsev ◽  
Alexander G. Bobylev

Proteins can perform their specific function due to their molecular structure. Partial or complete unfolding of the polypeptide chain may lead to the misfolding and aggregation of proteins in turn, resulting in the formation of different structures such as amyloid aggregates. Amyloids are rigid protein aggregates with the cross-β structure, resistant to most solvents and proteases. Because of their resistance to proteolysis, amyloid aggregates formed in the organism accumulate in tissues, promoting the development of various diseases called amyloidosis, for instance Alzheimer’s diseases (AD). According to the main hypothesis, it is considered that the cause of AD is the formation and accumulation of amyloid plaques of Aβ. That is why Aβ-amyloid is the most studied representative of amyloids. Therefore, in this review, special attention is paid to the history of Aβ-amyloid toxicity. We note the main problems with anti-amyloid therapy and write about new views on amyloids that can play positive roles in the different organisms including humans.


<i>Abstract.</i>—This chapter provides the history of the Caspian Kutum <i>Rutilus kutum</i> (Kamensky 1901) fishery in the Caspian Sea, analyzes long-term changes of stock condition and the main causes of fluctuations in abundance, and describes conservation measures that allowed resumption of fishing. Caspian Kutum (Cyprinidae family) is an endemic, semi-anadromous, medium-sized fish, reaching 53–67 cm in total length (rarely 71 cm) and weighing up to 4.0 kg (rarely 5.0 kg). Commercially important fisheries occur in Russia, Azerbaijan, Iran, and Turkmenistan. Flesh and roe are enjoyed as food and have a high price in markets. Variability in sea level, construction of hydroelectric power plants on rivers, water irrigation withdrawals, industrial and domestic pollution, overfishing, and illegal fishing resulted in a sharp decline of Caspian Kutum abundance and resulted in a total ban on harvest in Russia between 1995 and 2004. In Iran, fishing for Caspian Kutum continued due to their stocking program. Conservation measures for Caspian Kutum stocks (e.g., listing in federal and local Red Data books, fishing ban, fight against illegal fishing), as well as an increase of artificial propagation in Iran, Azerbaijan, and Dagestan (Russia) during subsequent years, have allowed the recovery of stocks in Russian waters to 1990s levels as well as the resumption of fishing. The follow lessons may be applicable to fishery management programs elsewhere:


2020 ◽  
Vol 19 (1) ◽  
pp. 10-25 ◽  
Author(s):  
Kaleem U Kakar ◽  
Zarqa Nawaz ◽  
Zhouqi Cui ◽  
Nazeer Ahemd ◽  
Xueliang Ren

Abstract Tobacco is one of the most widely cultivated nonfood cash crops, a source of income, model organism for plant molecular research, a natural pesticide and of pharmaceutical importance. First domesticated in South Americas, the modern-day tobacco (Nicotiana tabacum) is now cultivated in more than 125 countries to generate revenues worth billions of dollars each year. However, the production of this crop is highly threatened by the global presence of devastating infectious agents, which cause huge fiscal loss. These threats have been battled through breeding for acquiring disease resilience in tobacco plants, first, via conventional and now with the use of modern molecular breeding approaches. For efficacy and precision, the characterization of the genetic components underlying disease resistance is the key tool in tobacco for resistance breeding programs. The past few decades have witnessed significant progress in resilience breeding through advanced molecular techniques. The current review discusses history of tobacco breeding since its time of origin till date, highlighting the most widely used techniques and recent advances in molecular research and strategies for resistance breeding. In addition, we narrate the budding possibilities for the future. This review will provide a comprehensive and valuable information for the tobacco growers and researchers to deal with the destructive infectious diseases.


Author(s):  
Letícia Do Prado

 ResumoDorothy Crowfoot Hodgkin formou-se em química pela Somerville Oxford, doutorou-se em Cambridge e liderou o grupo de pesquisa que decifrou a estrutura molecular de várias moléculas biológicas complexas como: a penicilina, a vitamina B12 e a insulina. Seu nome não foi tão ovacionado quanto o de outros ganhadores do Prêmio Nobel já que seu método de trabalho, a cristalografia de raio X para a análise de moléculas complexas era ainda pioneiro e pouco disseminado entre os laboratórios da época. Foi a busca de soluções exatas para problemas difíceis que motivaram Dorothy a superar tempos de guerra, contratempos experimentais, demandas do casamento, da maternidade e a dor física persistente, para se tornar uma das maiores cientistas do século. Neste trabalho apresentaremos brevemente a vida de Dorothy, sua infância distante dos pais e rica em experiências culturais, sua juventude, as dificuldades que precederam sua entrada na Universidade e sua vida como pesquisadora, e mais especificamente, falaremos sobre sua colaboração para a solução da estrutura molecular da penicilina no cenário da Segunda Guerra Mundial. Nosso objetivo é apresentar ao leitor o trabalho de Dorothy ancorados em suas  publicações originais e suas biografias, de maneira a contribuir com a disseminação da história das mulheres na ciência. Palavras-chave: Dorothy Crowfoot Hodgkin; Penicilina; Mulheres na Ciência.AbstractDorothy Crowfoot Hodgkin graduated in chemistry from Somerville Oxford, doctorate from Cambridge and led the research group that deciphered the molecular structure of several complex biological molecules such as penicillin, vitamin B12 and insulin. Her name was not as ovation as that of other Nobel Prize winners since their method of working, X-ray crystallography for the analysis of complex molecules was still pioneering and little disseminated among laboratories of the time. It was the search for exact solutions to difficult problems that motivated Dorothy to overcome wartime, experimental setbacks, marriage demands, maternity, and persistent physical pain to become one of the greatest scientists of the century. In this work we will briefly present the life of Dorothy, her childhood far from her parents and rich in cultural experiences, her youth and the difficulties that preceded her entrance into the University and her life as a researcher, and more specifically, we will talk about her collaboration for the solution of molecular structure of penicillin in the scene of World War II. Our goal is to present the Doroty works, anchored in her original published and her biographies in order to contribute with the dissemination of history of women in science.Keywords: Dorothy Crowfoot Hodgkin; Penicillin; Women in Science.


Africa ◽  
1972 ◽  
Vol 42 (2) ◽  
pp. 122-139 ◽  
Author(s):  
Rosemary Harris

Opening ParagraphIkom, on the Cross River and with a total population of just over 7,000 in 1953, lies near the boundary between Nigeria and southern Cameroons. It has been commercially important in recent years, as was indicated, for example, by the presence there in 1953 (the date of the last fairly reliable census) of over 1,500 Ibo. But the Ibo are newcomers, and this paper is concerned with examining earlier patterns of trade as they had developed down to the nineteen-twenties. More recently the people of Ikom have derived their prosperity from the exploitation of their soil, which is eminently suitable for producing cocoa. According to a visiting soil scientist in the 1960s, there are in the locality 140 square miles of suitable cocoa land, which in fact is so plentiful that although two-thirds of it was still held in a forest reserve there was in 1966 no public pressure to have any portion released for agriculture. The affluence based on cocoa is, however, recent; the traditional path to prosperity and influence was through participation in trade, especially trade with Mamfe to the east and with Calabar on the coast, principally along the Cross River.


2021 ◽  
Vol 62 (01) ◽  
pp. 168-171
Author(s):  
Natig Elmaddin Ibrahimov ◽  

The process of gaining the importance of commercially important information in civil circulation has come a long way. The protection and disclosure of commercial secrets, which are among the objects of intellectual property, are becoming increasingly important for the legislation of Azerbaijan. The historical development of commercial secrets in Azerbaijan is closely related to the legislation of the Russian Empire. This was due to historical events. The history of the development of commercial secrets in Azerbaijan can be divided into several stages. The first stage is the feudal period, state structure and legal regulation of this period. The second period covers the period from 1861 to 1917. The third period covers the period from 1917 to 1991. The fourth period covers the period after 1991, the "restoration of capitalism". Nowdays, the protection of commercial secrets comes to the fore in connection with the relevance of globalization, integration and dynamic development of information resources, as well as the emergence of new obstacles and difficulties in legal regulation. Key words: commercial secrets, intellectual property law, Azerbaijani legislation, civil law, Tsarist Russia (Russian Empire), USSR, Azerbaijan SSR


2002 ◽  
Vol 52 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Yasuo Abe ◽  
Hiromi Ebara ◽  
Satoshi Okada ◽  
Ryuichi Akaki ◽  
Toyokazu Horii ◽  
...  

Polar Record ◽  
1963 ◽  
Vol 11 (74) ◽  
pp. 555-566 ◽  
Author(s):  
S. G. Brown

Since the early nineteen-twenties whaling in the Antarctic has dominated the world's whaling industry. In recent years, however, there have been increasing signs that the Antarctic industry is approaching an important crisis. There is no doubt that too many whaling expeditions are pursuing too few whales. This article attempts to review the present position of the industry, first dealing very briefly with the biology of the commercially important whales and the history of whaling generally and then discussing the development of Antarctic whaling and the events which have led to the present situation.


2016 ◽  
Vol 2 (25) ◽  
pp. 162 ◽  
Author(s):  
José Antonio Acevedo-Díaz ◽  
Antonio García-Carmona

Se presenta el caso de Rosalind Franklin sobre la elucidación de la estructura molecular del ADN como un relato de historia de la ciencia interesante para abordar algunas cuestiones de naturaleza de la ciencia (NDC), mediante un enfoque explícito y reflexivo. La propuesta se dirige a la formación inicial de profesorado en NDC y su didáctica. Se presta atención tanto a aspectos epistémicos como no-epistémicos en la narración del relato y en las cuestiones que se plantean para su reflexión. Asimismo, se proponen algunas recomendaciones metodológicas para su implementación en el aula, que se concretan en: (i) lectura de la controversia y respuesta en grupos pequeños a unas cuestiones sobre NDC; (ii) discusión conjunta en clase de las respuestas anteriores; y (iii) revisión de las respuestas iniciales a partir de la discusión en clase.


Author(s):  
George T. Trammell ◽  
James R. Breedlove

We consider the feasibility of an electron “molecular microscope” which could be used to determine the structure of a biological molecule by forming an image in which its individual atoms are resolved.Each atom which is imaged must scatter at least one electron. (This is true irrespective of the imaging technique so long as the images of neighboring atoms are resolved.) While we may ignore the effects of the elastically scattered electrons on the molecular structure, inelastic collisions will lead (with a certain probability) to molecular dissociation or rearrangement. The “image” formed will thus be a composite picture of the molecule over the history of its irradiation and may bear little relation to the original molecular structure, and this is a fundamental “Limitation on molecular microscopy.


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