Planning LHASA

Latorre C, Quade J, McIntosh WC (1997) The expansion of C4 grasses and global change in the late Miocene stable isotope evidence from the Americas. Earth Plan Sci Lett 146 83-96 Leier AL (2005) The Cretaceous evolution of the Lhasa terrane, southern Tibet, Ph.D. Dissertation, Univ. of Arizona... 

Logic and Heuristics Applied to Synthetic Analysis (LHASA) is an expert system for synthesis planning that assists chemists in designing efficient routes to target molecules for organic synthesis. 

Health promotion and social mobilization are major components of the National IDD Elimination Program that are mostly coordinated and carried out by the health sector in collaboration with other sectors. One of the main activities of the program has been the IDD Day in May of each year that involves all levels of government and the whole of civil society, and each year the event has a main theme. In May 2000, the 7th National IDD Day coincided with the launch of the Australia—China Tibet IDD Elimination Project in Lhasa, capital of the TAR. Since then a major advocacy event is planned around the IDD Day focusing on a specific province/autonomous region where the goal of IDD control is yet to be achieved. 

LHASA must recognize all of these and utilize them in its planning processes. The procedures by which these are called perception. 

This account of the LHASA and CAMEO programs has been necessarily very limited readers interested in further details should contact the suppliers of the software as listed in the Software appendix. Another approach to the problem of synthesis planning is to provide literature references to model reactions, thus allowing the chemist user to make his or her own assessment of feasibility, using his or her own expert system A number of reaction database systems are in common use (e.g., REACCS,... 

In this paper we describe how the ORAC reaction database system has been integrated with the LHASA synthesis planning program. This interface allows literature precedents for synthetic steps proposed by LHASA to be retrieved from ORAC and displayed to the user. The problem of sequence searching in reaction database systems is also explored and approaches to this problem are described. Finally, the potential use of synthesis planning systems to identify and classify links between reactions in ORAC for use during sequence searching is considered. 

The primary purpose of a reaction database system is to provide quick and easy access to the reaction literature. Users of synthesis planning programs have a need for such access to the literature in elaborating routes suggested by an analysis. An interface between LHASA and ORAC has recently been developed to provide such a link. The interface allows literature precedents for synthetic steps proposed by LHASA to be retrieved automatically from ORAC s database of over 120,000 reactions and to be displayed to the user on an ORAC Display Form. Company databases can also be accessed to search and display in-house preparative methods and processes in conjunction with databases supplied by ORAC Ltd. 

However, there are some associated problems with this approach. The long-range transforms, which were created based on the expectations of a small set of expert chemists, took as much as 6 months to prepare, and the program could easily give cumbersome plans for molecules that contained unusual or unforeseen combinations of functional groups. In addition, since the modules were not dynamically updated when new reactions were added, the modules slowly slipped out of date as new reactions were discovered. LHASA is still in use today, and new strategic modules are still being added. ... 

The wide range of functionality offered by HLI should make it the ideal vehicle for interfacing synthesis planning systems such as LHASA to reaction and structure... 

---