An Empirical Evaluation of Distribution-based Thresholds for Internal Software Measures

The problems encountered in achieving data security within computer-supported information systems increased with the development of modern computer systems. The threats are manifold and have to be met by an appropriate set of hardware precautions, organizational procedures and software measures which are the topic of this paper. Design principles and software construction rules are treated first, since the security power of a system is considerably determined by its proper design. A number of software techniques presented may support security mechanisms ranging from user identification and authentication to access control, auditing and threat monitoring. Encryption is a powerful tool for protecting data during physical storage and transmission as well.Since an increasing number of health information systems with information-integrating functions are database-supported, the main issues and terms of database systems and their specific security aspects are summarized in the appendix.

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Computationally Augmented Retrosynthesis: Total Synthesis of Paspaline A and Emindole PB

10.26434/chemrxiv.7322330.v1 ◽

2018 ◽

Author(s):

Timothy Newhouse ◽

Daria E. Kim ◽

Joshua E. Zweig

Keyword(s):

Chemical Synthesis ◽

Total Synthesis ◽

Small Molecules ◽

First Principles ◽

Quantum Chemical ◽

Computational Analysis ◽

Empirical Evaluation ◽

Synthetic Strategy ◽

Catalyzed Reactions ◽

Enzyme Catalyzed Reactions

The diverse molecular architectures of terpene natural products are assembled by exquisite enzyme-catalyzed reactions. Successful recapitulation of these transformations using chemical synthesis is hard to predict from first principles and therefore challenging to execute. A means of evaluating the feasibility of such chemical reactions would greatly enable the development of concise syntheses of complex small molecules. Herein, we report the computational analysis of the energetic favorability of a key bio-inspired transformation, which we use to inform our synthetic strategy. This approach was applied to synthesize two constituents of the historically challenging indole diterpenoid class, resulting in a concise route to (–)-paspaline A in 9 steps from commercially available materials and the first pathway to and structural confirmation of emindole PB in 13 steps. This work highlights how traditional retrosynthetic design can be augmented with quantum chemical calculations to reveal energetically feasible synthetic disconnections, minimizing time-consuming and expensive empirical evaluation.

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