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SynopsisConformational analyses of cyclic tetrapeptides consisting of alternating cis and trans peptide units have been made using contact criteria and energy calculations. This study has been restricted to those structures having a symmetry element in the backbone ring, such as a twofold axis ( d ) or a center of inversion (i). There are five main results. (1) There are two distinct types of conformations, which are stereochemically favorable corresponding to each of twofold and inversion-symmetrical structures, designated as d l , d z (for twofold symmetrical) and il, iz (for inversion-symmetrical). Among these, the i l type has the lowest energy when glycyl residues occur a t all four a-carbon atoms. (2) With the glycyl residue a t all four a-carbon atoms, methyl substitution a t the cis peptide nitrogen atoms is possible in all the four types, whereas the substitution a t trans peptide nitrogen atoms is possible only for the i l type. Thus only in the i l type can all the nitrogen atoms be methylated simultaneously. The conformation of the molecule in the crystal structure of cyclotetrasarcosyl belongs to the il type. (3) When alanyl residues occur a t all four a-carbon atoms, the possible symmetrical type is dependent on the enantiomorphic form and the actual sequence of the alanyl residues. (4) The methyl substitution a t peptide nitrogen atoms for cyclic tetrapeptides having alanyl residues causes more stereochemical restriction in the allowed conformations than with glycyl residues. (5) The prolyl residue can be incorporated favorably a t the cis-trans junction of both d and i types of structures. The results of the present study are compared with the data on cyclic tetrapeptides available from the crystal structure and nmr studies. The results show an overall agreement both regarding the type of symmetry and the conformational parameters.

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Most of the woman nowadays is ending up their life at middle age between 35-50 years, reason they are suffering from Cervical related cancer tumours. Many women are unaware of having cervical related cyst in the early stages. A survey was conducted on classifiers such as Decision Tree, Multilayer Perceptron, and Nave Bayes, with True Positive Rate, False Positive Rate, Precision, and Recall being measured, and an Android Mobile App was built to forecast the risk of having a Cervical associated cyst in its early stages. For training and testing the classifiers, we have used cervical dataset from University of California at Irvine Machine Learning Repository. Cervical Dataset consists of 858 records containing 32 attribute values and 4 diagnosis class value. For Cervical cancer prediction only 21 attributes and 1 biopsy class value is considered. The proposed Android Mobile App capable of predicting risk of a woman is affected by cervical related cyst in early stages. A normal woman can identify chances of having Cervical Cancer at finger tips with the proposed Android Mobile App.

Conformational aspects of 4 → 1 hydrogen bonded cyclic pentapeptides are considered in this paper from the point of view of “contact criteria” and potential energy calculations. Three types of such hydrogen bonded conformations, designated A1, A2 and B, are possible, involving some amount of strain on the bond angles. The energy of hydrogen bonded cyclopentaglycyl is somewhat less than that of the five‐fold symmetrical conformation. The stereochemical feasibility of introducing l‐ and d‐alanyl residues in these structures has also been studied and the possible types for different sequences of alanyl residues have been determined. The results are discussed further in the light of the limited data available from crystal structure and nuclear magnetic resonance studies on cyclic pentapeptides.