Tadalafil gehört zur Gruppe der PDE5-Hemmer und wirkt über eine hochselektive Blockade des Enzyms Phosphodiesterase Typ 5. Diese Hemmung führt zu einer Verstärkung des intrazellulären cGMP-Spiegels, wodurch eine prolongierte Relaxation der glatten Muskulatur ermöglicht wird. Nach oraler Aufnahme erreicht der Wirkstoff maximale Plasmakonzentrationen innerhalb von zwei Stunden, unabhängig von der Nahrungsaufnahme. Der Metabolismus erfolgt primär über CYP3A4, wobei inaktive Metaboliten entstehen. Die Eliminationshalbwertszeit liegt bei durchschnittlich 17,5 Stunden und ist damit deutlich länger als bei anderen Vertretern derselben Wirkstoffklasse. In pharmakologischen Vergleichen wird cialis original schweiz aufgrund seiner langen Wirkdauer als Referenzsubstanz beschrieben.

Scifinder-powerpoint.pdf

Introduction to Searching
SciFinder Scholar
What is SciFinder Scholar?
• Desktop access to databases from CAS
• http://www.cas.org/SCIFINDER/SCHOLAR/
• Usage Conditions apply
• Key Co-Ordinator
What does Scholar Search?
• Over 16 million bibliographic records from
over 8,000 journals and from major patent
organizations (from 1967)
• Over 22 million chemical substance records
(from 1957)
– all classes of substances
• Almost 4 million chemical reactions from over
100 journals (from 1985) and from selected
patents (from 1991)
• See http://www.cas.org/casdb.html
Coverage of Scholar at VUW
Records in Scholar 1995,
• Listed affiliations in Scholar for Departments/
Schools at VUW from 1995 onwards
Some Features of Scholar
Updates daily
Broad coverage across sciences
Desktop access
Automatic truncation/proximity
24 Hour access
Automatic application of synonyms
Bibliographic records from 1967
Structure searching
Reference linking
Reaction searching
substance
bibliographic
reaction
database
database
database
Explore by:
Explore by:
Chemical Name
Research Topic
CAS Registry Number
Molecular Formula
Chemical Structure
Refine by:
Explore by:
- exact or related
Research Topic
Chemical Reaction
- substructure
then Get Reactions
Document Type
Language
Publication Year
Answers are
Answers are
Answers are
chemical substances
bibliographic records
chemical reactions
(CAS Registry Numbers)
Bibliographic Record in Scholar
Title and Bibliography …
… followed by Abstract …
… and Indexing
Exercise 1
• Key points
– titles and abstracts written by authors
– “free text” by authors …
… indexers apply indexing policies
• Think how authors and indexers may
have written about your topic
CAS Indexing for Substances
When new information
about a substance is
reported the precise CAS
Registry Number is
potassium in blood
potassium ions in blood
analysis of morphine
analysis of morphine sulfate
Explore by Research Topic
• Enter Phrase
• Select Candidates
• Get References
Interpreting the Research Topic
• Prepositions/conjunctions
• List of candidates with concepts “closely
associated” and “anywhere”
• Combinations of concepts
• Truncation/singulars/plurals/”synonyms”/
CAS abbreviations
• Adding synonyms at Explore and Refine
• AND OR
• Distributive modifiers
• Look carefully at the list of
candidates to see how Scholar
has interpreted your query
• Think!
• If unsure, check Table 1
Exercises 2 and 3
• “Find information on the use or the
abuse of anabolic steroids”
– limit to humans, Reviews, English
language and Publication Year 1996-
– print a full record and save all answers
• “Find preparations in patents on
dihydrotestosterone”
– print full substance record and display a
European Patent
Exercise 4
• “Find publications by
Daryle H Busch”
(ACS President 1999)
– Alternative spellings
– Use initial for given name
• Explore CAS Registry Number
hyperlinking
Asking the Right Question
• Understanding of the
– topic
– literature
– database
• Author/Indexer issues
– bibliographic databases
(author/indexer)
– substance/reaction databases (indexer)
Information on a substance
• Comparison of starting with:
– Explore by Research Topic
– Explore by Chemical Substance/ Substance Identifier then Get
References
• Searching for substances by name in Research Topic
searches name/CAS RNs
– may lack precision but may aid comprehension
– name as part of phrase, auto-truncation, sentence proximity,
need to check that CAS RN has been searched
• Searching for information on substances through
Substance Identifier then Get References is precise -
searches CAS RNs
Information on Substances
• Balance comprehensiveness with precision
• Searches for information on substances can be
conducted in two basic ways and it is important to
realise the benefits/limitations of the options
• Sometimes groups of substances are better
retrieved through Explore by Research Topic;
sometimes through Explore by Chemical
Substance
• Try options!
Exercise 5
• Try your own, or try “I am interested in…”
– forensic studies in drug overdose
– warning (prediction) of earthquakes
– pharmaceuticals for treatment of glaucoma
– defense pheromones used by animals
(insects)
– studies of DNA of cheetahs (acinonyx)
– using satellites for geographic information
systems (GIS)
• “I wanted information on inks used
by Gutenberg in his printing press”
although I amended my search to
• “I am interested in inks used by
Gutenberg (history, archeology,)”
Explore by Chemical Structure
• It is essential that you understand CAS
registration policies for structures!
• Most are the same as taught in College
Chemistry Classes although additional
issues include:
– Multicomponent substances;
– Salts, polymers, mixtures, alloys, hydrates;
– Structure connection tables for aromatic
compounds, tautomers, π- and donor-
bonding
Exercise 6
• Indexing examples:
– ferrocene and π-complexes
– dimethyl sulfoxide and donor bonding
– augmentin and mixtures
– pyridinium tosylate and salts
– ABS and co-polymers
– Steel 10 and alloys
Exercise 7
Freehand
Shortcuts
User variables
variables
Templates
Ring/chain
Blocking
locking tool
Common atoms
substitution
Drawing
reactions
Exercise 8
Pasting CAS Registry Numbers
Carefully copying a CAS Registry
Number from a record, and pasting
into the structure drawing program …
… offers a very quick alternative to
drawing a structure …
… which may be modified by the
structure drawing tools
Other Structure Drawing Hints
• Using Shortcuts
• Blocking substitution
• Using the locking tool
– ring default is isolated/embedded
– chain default is ring/chain
Searching Structures: Options
Structure Search Options
Preview Sample Answers allows you to see sample of actual answers
Preview Real-Atom Attachments analyzes answers by atoms attached
to free positions
Exact match or a related structure allows only H-attachments on
structure drawn (related includes multicomponent substances with the
exact match as one component)
Substructure allows substituents at vacant positions
Get Reactions has search options on reaction role, bond/atom
mapping
SUBSTRUCTURE
SUBSTRUCTURE
Structures too general
• Structure searching
– screen
– atom-by-atom match
– analyze
– display
• Very general structures may exceed
system limits
– autofix (lock rings/chains)
– build more complex structure
Exercise 9
• Build structure
• Do exact search
• Do substructure search (autofix OK)
• Get References - reactant
• Display
• Build reaction query
• Search for reactions (autofix OK)
• Display
Exercise 10
Using structures to refine substances
• Structure refinements of substance
records easily performed
• Think of cases where this may be of
special value .
… monochlorotetralins
… radicals, cations, anions
Using research topics to refine references
Substance
Bibliographic
Reaction
database
database
database
Explore by:
Explore by:
Chemical Name
Research Topic
CAS Registry Number
Molecular Formula
Chemical Structure
Refine by:
Explore by:
- exact or related
Research Topic
Chemical Reaction
- substructure
then Get Reactions
Document Type
Language
Publication Year
Answers are
Answers are
Answers are
chemical substances
bibliographic records
chemical reactions
(CAS Registry Numbers)
Conclusion
• Information retrieval is a science
• Apply scientific method!
– observe
– explore
– understand
– think creatively
– explore new ideas
• Search the literature thoroughly

Source: http://www-organik.chemie.uni-wuerzburg.de/praktika/download/SciFinder-Powerpoint.pdf