β-Cyclodextrin Substituted Polyoxyethylene in the Synthesize of Polycarboxylate Superplasticizers

Author(s):  
Bin Li ◽  
Ling Wang

In this study, the starch-based material β-cyclodextrin was used as the original material to substitute petrochemical product-polyoxyethylene (HPEG) to synthesize concrete admixture polycarboxylate superplasticizer (PCE). During the synthesis, β-cyclodextrin was first grafted on the PEO chain to prepare β-CD-HPEG by click reaction. Then β-CD-HPEG was used to substitute the macromonomer HPEG to synthesize β-CD-PCE. When the substitution amount HPEG was 3%, the synthesized β-CD-PCE showed better dispersion ability.

Author(s):  
Jesse Ferris

This book draws on declassified documents from six countries and original material in Arabic, German, Hebrew, and Russian to present a new understanding of Egypt's disastrous five-year intervention in Yemen, which Egyptian president Gamal Abdel Nasser later referred to as “my Vietnam.” The book argues that Nasser's attempt to export the Egyptian revolution to Yemen played a decisive role in destabilizing Egypt's relations with the Cold War powers, tarnishing its image in the Arab world, ruining its economy, and driving its rulers to instigate the fatal series of missteps that led to war with Israel in 1967. Viewing the Six Day War as an unintended consequence of the Saudi–Egyptian struggle over Yemen, the book demonstrates that the most important Cold War conflict in the Middle East was not the clash between Israel and its neighbors. It was the inter-Arab struggle between monarchies and republics over power and legitimacy. Egypt's defeat in the “Arab Cold War” set the stage for the rise of Saudi Arabia and political Islam. Bold and provocative, this book brings to life a critical phase in the modern history of the Middle East. Its compelling analysis of Egypt's fall from power in the 1960s offers new insights into the decline of Arab nationalism, exposing the deep historical roots of the Arab Spring of 2011.


2020 ◽  
Vol 68 ◽  
pp. 29-64
Author(s):  
N.S. Probatova ◽  

The paper summarizes information on chromosome numbers (CNs) of the Grass species (Poaceae) in the flora of Russian Federation, obtained on the original material, most part - from the Russian Far East (RFE). In some species the CNs are known in Russia or in the world only from RFE, in some – from one locality or few, or from one subregion of RFE. The grass species in RFE often occur in mountain regions and near seacoasts; some species are endemics, some were studied near the limits of their geographical distribution areas. The diversity of CNs, the special features of the CNs distribution in some grass groups are discussed. The alien species are abundant in RFE, and their CNs are also involved in the study. For karyologically polymorphous species further studies are needed.


Author(s):  
С. А. Лысак ◽  
З. В. Лысак

Наведені результати 2008–2011 років дослідженьіз пошуку стійкості вихідного матеріалу томатапроти чорної бактеріальної плямистості. Дослі-джено 424 колекційних зразка томату різногоеколого-географічного походження. Колекційнийматеріал диференційований за рівнем полігенноїстійкості на природному фоні ураження протичорної бактеріальної плямистості (Xanthomonasvesicatoria Dowson). Виділені до даної хворобистійкі зразки й еталони-диференціатори рекомен-дуються для використання в селекційній роботіза даною ознакою. Research of 2008–2011 resistance of tomato original material toblack bacterial blight is considered in the article. Studied of 579collection samples of a tomato of a different ecological andgeographical origin. The collection material is differentiated onlevel of polygene stability to black bacterial blight (Xanthomonasvesicatoria Dowson). The steady samples allocated to givenillness and standards differentiator are recommended for using inselection work to the given sign.


2019 ◽  
Vol 23 (8) ◽  
pp. 860-900 ◽  
Author(s):  
Chander P. Kaushik ◽  
Jyoti Sangwan ◽  
Raj Luxmi ◽  
Krishan Kumar ◽  
Ashima Pahwa

N-Heterocyclic compounds like 1,2,3-triazoles serve as a key scaffolds among organic compounds having diverse applications in the field of drug discovery, bioconjugation, material science, liquid crystals, pharmaceutical chemistry and solid phase organic synthesis. Various drugs containing 1,2,3-triazole ring which are commonly available in market includes Rufinamide, Cefatrizine, Tazobactam etc., Stability to acidic/basic hydrolysis along with significant dipole moment support triazole moiety for appreciable participation in hydrogen bonding and dipole-dipole interactions with biological targets. Huisgen 1,3-dipolar azide-alkyne cycloaddition culminate into a mixture of 1,4 and 1,5- disubstituted 1,2,3-triazoles. In 2001, Sharpless and Meldal came across with a copper(I) catalyzed regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles by cycloaddition between azides and terminal alkynes. This azide-alkyne cycloaddition has been labelled as a one of the important key click reaction. Click synthesis describes chemical reactions that are simple to perform, gives high selectivity, wide in scope, fast reaction rate and high yields. Click reactions are not single specific reaction, but serve as a pathway for construction of simple to complex molecules from a variety of starting materials. In the last few decades, 1,2,3-triazoles attracted attention of researchers all over the world because of their broad spectrum of biological activities. Keeping in view the biological importance of 1,2,3-triazole, in this review we focus on the various synthetic routes for the syntheisis of 1,4-disubstituted 1,2,3-triazoles. This review involves various synthetic protocols which involves copper and non-copper catalysts, different solvents as well as substrates. It will boost synthetic chemists to explore new pathway for the development of newer biologically active 1,2,3-triazoles.


2013 ◽  
Vol 10 (10) ◽  
pp. 738-743 ◽  
Author(s):  
Azadeh Fazeli ◽  
Hossein Oskooie ◽  
Yahya Beheshtiha ◽  
Majid Heravi ◽  
Hassan Valizadeh

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