نتایج جستجو برای: more or equal

تعداد نتایج: 4635042  

Journal: :The Health service journal 1990
W Moore

Journal: :Chemical communications 2015
M Therkelsen M T Rasmussen A T Lindhardt

Two decarboxylative methods providing access to N-alkylated α-trihalomethylated heterocyclic amines have been developed. A batch protocol in which methyl trifluoroacetate acts both as a methylating reagent and subsequently as a nucleophilic trifluoromethyl anion precursor upon its addition to (iso)quinoline derivatives. Next, a telescoped continuous flow process, forming the corresponding α-tri...

2014
KENNETH W. TUPPER

“IS IT TOO MUCH TO HOPE that a system of education may some day be devised, which shall give results, in terms of human development, commensurate with the time, money, energy and devotion expended? In such a system of education it may be that mescaline or some other chemical substance may play a part by making it possible for young people to “taste and see” what they have learned about at secon...

Journal: :Organic & biomolecular chemistry 2015
Shihe Hu Bingyang Wang Yu Zhang Weifang Tang Mengyuan Fang Tao Lu Ding Du

A novel synthetic approach to functionalized indolo[2,3-a]quinolizidines is developed via an N-heterocyclic carbene (NHC)-catalyzed annulation of cyclic β-enamino esters with enals . This methodology offers a pathway for quick and efficient construction of an indolo[2,3-a]quinolizidine skeleton which is a core structure of many natural products with diverse bioactivities.

2015
Kun Zhang Huan-huan Li Peter Grünberg Qiang Li Sheng-tao Ye Yu-feng Tian Shi-shen Yan Zhao-jun Lin Shi-shou Kang Yan-xue Chen Guo-lei Liu Liang-mo Mei

Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-curr...

Journal: :The Australian journal of physiotherapy 2002
Megan Davidson

This paper outlines a practical approach to assist physiotherapists to interpret the results of diagnostic or screening tests. Diagnostic tests are used during clinical assessment to increase or decrease the clinician's estimate of the likelihood that a client has a particular condition. A negative result for a test that is 100% sensitive can rule a condition out (SnOUT), and a positive result ...

Journal: :Dalton transactions 2012
Johanna Tornatzky Axel Kannenberg Siegfried Blechert

The importance of unsymmetrical N-heterocyclic carbenes (uNHCs) as ligands in metal-catalyzed reactions is undeniable. While uNHCs show similar properties as compared with symmetrical NHCs, dissymmetrization allows for further fine-tuning. The introduction of chelatization, hemilability, bifunctionality, shielding effects, and chirality-transfer influences the catalyst's stability, reactivity, ...

Journal: :Chemical communications 2005
Polly L Arnold Mark Rodden Claire Wilson

Alkoxide-functionalized N-heterocyclic carbenes (NHCs) stabilise the potassium-imidazole-2-ylidene fragment against 1,2 alkyl rearrangement reactions; this allows the first structural characterisation of a potassium NHC complex, which reveals distorted and unusual bonding interactions between the imidazole ring and the potassium cation.

Journal: :New South Wales Public Health Bulletin 2002

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