Climbers

Why put such extraordinary effort into the laboratory synthesis of a molecule so easily obtained from natural sources There are many reasons. On a basic human level, a chemist might be motivated primarily by the challenge, much as a climber might be challenged by the ascent of a difficult peak. Beyond the pure challenge, the completion of a difficult synthesis is also valuable for the way in which it establishes new standards and raises the field to a new level. If vitamin Bj2 can t>e made, then why can t any molecule found in nature be made Indeed, the three and a half decades that have... 

England, and received his D.Sc. from the University of Manchester with William Henry Perkin, Jr. After various academic appointments, he moved in 1930 to Oxford University, where he remained until his retirement in 1955. An accomplished mountain climber, Robinson was instrumental in developing the mechanistic descriptions of reactions that we use today. He received the 1947 Nobel Prize in chemistry. 

Picrotoxin is a mixture of pircotin (non-toxic) and picrotoxinin, which occurs in the seeds of the Asiatic climber Anamirta cocculus (levent berry, cockles). It is a non-competitive antagonist at the y -aminobutyric acidA (GABAa) receptor. 

Two rock climbers stand at the bottom of a rock face they estimate to be 155 feet high. Their rope is 65 m long. Is the rope long enough to reach the top of the cliff ... 

C06-0008. Which of the following are state functions (a) height of a mountain (b) distance traveled in climbing that mountain (c) energy consumed in climbing the mountain and (d) gravitational potential energy of a climber on top of the mountain... 

From the data given, when the climber goes 20 ft directly north the elevation increases 20 ft ... 

One strategy that has often been used is to proceed along the path of steepest ascent until a maximum is reached. Then another search is made. A path of steepest ascent is determined and followed until another maximum is reached. This is continued until the climber thinks he is in the vicinity of the global maximum. To aid in reaching the maximum, the technique of using three points to estimate a quadratic surface, as was done previously, may be used. 

A. indica L. Indian Aristolochia, also known as Indian birthwort, ishvara (Sanskrit), or adagam (Tamil), is a bitter climber native to India. The medicinal material consists of the rhizome, which is to resolve inflammation (India), counteract insect poison, and as an antipyretic (Philippines and Vietnam). The rhizome contains aristolochic acid, which inhibits in vitro and dose-dependent phospholipid hydrolysis by the human synovial fluid phospholipase A2, snake venom phospholipase A2, porcine pancreatic phospholipase A2, and human platelet phospholipase A2 (2). 

In Malaysia, a decoction of the roots is drunk to assuage stomachaches. The potential of this climber as a source of molecules affecting the serotoninergic neurotransmission would be worth investigating because (-)-discretamine characterized from Fissistigma glaucescens blocks a,- and ( -adrenoceptor and exerts a 5-hydroxytryptamine-... 

Ipomoea obscura (L.) Ker-Gawl., or obscure morning glory, is a slender climber common on fences. It is native to tropical East Africa, the Mascarene Islands, tropical Asia, throughout the Malay Archipelago, to northern Australia and Fiji. The leaves are cordate to 5 cm long and the flowers are infundibuliform and creamy white (Fig. 35). 

The family Celastraceae consists of about 50 genera and 800 species of trees, shrubs, or climbers known to produce a series of phenethylamine alkaloids that might hold some potentials as sources of dopaminergic agents. About 30 plant species of Celastraceae are medicinal in the Asia-Pacific region. 

The family Menispermaceae consists of 70 genera and about 400 species of tropical climbers that have attracted a great deal of interest on account of their ability to elaborate... 

The family Hernandiaceae consists of four genera Hernandia, Illigera, Gyrocarpus, and Sparattanthelium, and about 60 species of trees, shrubs, and woody climbers widespread in tropical regions. An example of Hernandiaceae is Hernandia ovigera L., which is grown as a tropical street tree. Hernandiaceae are member of the order Laurales and are known to abound with aporphines and lignans. 

The family Rubiaceae consists of about 450 genera and 6500 species of tropical and subtropical trees, shrubs, climbers, and herbs that are known to abound with iri-doid glycosides (monoterpenoid alkaloids, tannins, and anthraquinones). When looking for Rubiaceae in field collection, one is advised to look for plants with opposite simple leaves with an interpetiolar stipule, tubular flowers, which are often white, and capsules, berries, or drupes. 

A friend states that more rock climbers are killed traveling by automobile than are killed rock climbing. Is this statement supported by the accident statistics ... 

The data from Table 1-4 show that traveling by car (FAR = 57) is safer than rock climbing (FAR = 4000). Rock climbing produces many more fatalities per exposed hour than traveling by car. However, the rock climbers probably spend more time traveling by car than rock climbing. As a result, the statement might be correct but more data are required. 

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