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Gevaarlijke producten : Etiketten
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Het doel van deze presentatie is de verschillen vergelijken tussen oude en nieuwe etiketten van chemische producten.

Klik je op de verschillen van bv. H-zin, dan krijg je een aanvullende uitleg over de betekenis ervan.

Verder vind …


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Natuurrampen : Soorten
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Deze bijdrage bevat hyperlinks naar filmfragmenten, die ondersteund worden met uitleg in de presentatie. Op die manier worden de betekenis en de gevolgen van een natuurramp telkens toegelicht.

 


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Detecting Down’s syndrome in the unborn fetus
Down's syndrome is the condition that is screened for the most in pregnant women because of the increased risk with the increasing age of mothers. This unit describes several bioanalytical tests, and how these are used in conjunction with scans to screen and diagnose the condition. First published on Fri, 20 Jul 2012 as
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3 Reading activity

You will shortly be asked to read through a research paper published in the Journal of Medicinal Chemistry, in which the synthesis and structure–activity relationships of doxazosin and related compounds are described. It has been provided:
Author(s): The Open University

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Introduction

This unit examines how organic chemistry is used within the pharmaceutical industry to develop new drugs. You will investigate the process of drug development by following one new product through the intial process and research programme.

This unit is from our archive and it is an adapted extract from Organic chemistry: A synthesis approach (S344) which is no longer in presentation. If you wish to study formally at The Open University, you may wish to explore the courses we offer
Author(s): The Open University

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Acknowledgements

Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence

Grateful acknowledgement is made to the following sources for permission to reproduce material in this unit:

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2.14 Summing up

Activity 13

0 hours 5 minutes

Dr. Peterson concludes the audio sequence with a summary of all the points covered.

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2.11 Consequences of human / chimp pairing

Activity 10

0 hours 10 minutes

This clip refers back to the table of molecular characters, which is shown again here (Figure 9). It explains the consequences of human / chimp pairing in terms of homol
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2.10 Chimps, gorillas and humans

Activity 9

0 hours 10 minutes

Dr. Patterson uses a diagram showing alternative cladograms for humans, chimpanzees and gorillas (Figure 10) to summarise evidence supporting the hypothesis that chimps a
Author(s): The Open University

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2.8 Systematic hierarchy

Activity 7

0 hours 10 minutes

This clip builds on the idea that development recapitulates systematic hierarchy, by trying it out with the wrist bones of hominoids.

At the end of the clip, Dr. P
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2.6 Three schools of classification

Activity 5

0 hours 10 minutes

This clip explores the three kinds of relationships that have been explained so far, in terms of the work of Simpson, Mayr and Hennig, which are referred to as Simpsonian
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4.1 The rate of evolution

I now want to move away from looking at the challenges facing all aquatic mammals, to examine very briefly what we know about the evolutionary history of the cetaceans. This group has travelled furthest from its terrestrial roots and made the fullest adaptation to life in the sea.

Since mammals evolved on land, it has long seemed reasonable to suggest that the origin of whales must have involved an evolutionary transition from the land to the water. But how can we explain the fact that
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2.1 Land versus water

Mammals share a number of biological characteristics that mark them out as members of the class Mammalia. Many of these are adaptations to a life on land. For example:

  • Mammals give birth to young at a relatively advanced stage of development and feed their young on milk.

  • Most mammals have hair, or fur, covering part or all of the body.

  • Mammals have a high metabolic rate and maintain a relatively high and constant body temp
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Learning outcomes

By the end of this unit you should be able to:

  • contrast the physical properties of air and water and describe implications of such differences for aquatic mammals;

  • give examples of the adaptations displayed by aquatic mammals that enable them to hold their breath while submerged for relatively long periods;

  • describe some of the biological differences between pinnipeds, sirenians and cetaceans;

  • discuss the importance of communication b
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Acknowledgements

The content acknowledged below is Proprietary (see terms and conditions) and is used under licence.

Grateful acknowledgement is made to the following sources for permission to reproduce material in this unit:

Figures

Figure 2(f) © National Power;

Figure 3 Courtesy of IBM Corporation, Research Division, Almaden Research Center;

Figure 14 ‘Fuel hoarder sentenced’ by Maurice Weaver, printed 6 April 2001, Telegraph Gro
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5.1 Molecular reactivity is concentrated at key sites

Reactivity is not spread evenly over a molecule; it tends to be concentrated at particular sites. The consequences of this idea are apparent in the chemistry of many elements. However, in organic chemistry, the idea has proved so valuable that it receives specific recognition through the concept of the functional group. Structure 6.1 shows the abbreviated structural formula of hexan-1-ol, an alcohol.


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4.4 A classification of chemical substances

We now have a provisional but useful classification of chemical substances. First they are divided into molecular and non-molecular types, largely on the basis of their structures. Then a further division is made according to the major source of the chemical bonding holding their atoms together. In molecular substances, the bonding is covalent, but in the non-molecular class, it may be covalent, ionic or metallic. This classification is shown in Figure 32. For a recent and interesting example
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3.6 Summary of Section 3

  1. The electronic configuration of an atom can be obtained by allocating its electrons to s, p, d and f sub-shells in the order given by Figure 21. This procedure generates a periodicity in electronic configuration which matches that of the Periodic Table.

  2. The typical elements have
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1.7 Summary of Section 1

  • All materials are made of atoms of about 120 different chemical elements, each element being characterised by an atomic number which lies in the range 1–120.

  • Each atom has a nucleus where most of its mass resides. The atomic number is equal to the number of units of positive charge on the nucleus, the number of protons in the nucleus, and to the number of surrounding electrons in the neutral atom.

  • The nuclei of nearly all atom
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3.2 Stationary states and scattering in one dimension

The key idea of the stationary-state approach is to avoid treating individual particles, and to consider instead the scattering of a steady intense beam of particles, each particle having the same energy E0. It is not possible to predict the exact behaviour of any individual particle but, if the incident beam is sufficiently intense, the result of the scattering will be reflected and transmitted beams with steady intensities that are determined by the reflection and transmis
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