AROMATIC INTERACTIONS IN PEPTIDES : DESIGNED HELICES AND β-HAIRPINS

Design of complex protein folds requires complete understanding of the stereochemical principles that govern polypeptide chain folding. Extensive studies on design and synthesis of specific secondary structures like β-helices, β -sheets and hairpins have taught us that the unnatural amino acid aminoisobutyric acid (Aib) can be successfully employed for helix nucleation and tight turns of appropriate stereochemistry are facilitated by the use of DPro-Xxx sequences. Availability of such rigid secondary structure scaffolds therefore permits the design of synthetic peptides that can be used as models for investigation of tertiary interactions, primarily that of aromatic residues. Chapter 1 summarizes the present knowledge of peptide design using non-protein amino acids. The chapter also details the unique features of aromatic amino acids, especially tryptophan, and their employment as secondary structure stabilizing elements. Chapters 2-7 contain detailed descriptions of the work carried out on design, synthesis, and structural characterization of designed peptides containing aromatic amino acids. In Chapter 2, the use of aromatic pairs in strand segments of peptide hairpins has been discussed with the results clearly indicating that aromatic interactions at the non-hydrogen bonding position of peptide hairpins contribute to structure stability. In Chapter 3, accommodation of the Leu-Trp-Val segment in helical scaffolds the role of Trp residues in crystallization has been discussed. Chapter 4 outlines the influence of a large number of Trp residues on the preferred backbone conformation, with the studies clearly indicating a preference for helical scaffolds in small peptides. The role of Trp residues at turn regions of peptide hairpins has been discussed in Chapter 5, using examples from both synthetic peptides and from natural peptides containing Pro-Trp segments. The studies suggest that the Pro-Trp segments serve as helix nucleators and disrupt formation of peptide hairpins. The results of this study have been further extended to Conus monile peptides, discussed in Chapter 6. The studies also suggest the role of an aromatic-Pro segment on the cis-trans isomerization of the Xxx-Pro tertiary amide unit. Chapter 7 discusses the contribution of a Cys-His vs Tyr-His pair on strand segment stability in diproline nucleated peptide hairpins. Chapter 8 summarizes the key findings of the work. Chapter 9 lists the references cited in the thesis and the Appendix chapter provides details of experimental techniques used in the study.

Vehicles and Women's Life Changes: Ambai's Short Story

Tamil Short Stories considered to be one of the contemporary Literary forms. From the very beginning of short story till it has reduced to a size of a paragraph it has undergone various changes in structure, pattern and contextualization. Similarly, the short story "Vaganam" written by Ambai in the year 1971 expresses the stress and pressure of the women and making the same a driving force to achieve success. This research paper critically analysis the struggle, challenges success and changes faced by the women folk which is quite obvious in the recent scenario with reference to Ambai's short story  "Vaganam" The usage of advance technologies to drive this computer is less polluting to the environment and less harmful to humans than the various vehicles such as cars. Arrow can be seen to be disciplining women as there are numerous different uses of the computer and it is safe for women to travel this way

A STUDY ON COHOMOLOGY RINGS

Cohomology is a general term for a sequence of abelian groups defined from a cochain complex. That is, cohomology is defined as the abstract study of cochains, cocycles and coboundaries. Cohomology can be viewed as a method of assigning algebraic invariants to a topological space that has a more refined algebraic structure than the homolog

Human Relations in The Worship of Deities Found in Ancient Tamil Literary Songs

The Tamils divided the land into five kinds, according to the characteristics of land, and made it a tradition to cherish and enrich nature, realized that the fallen flowers did not stick to the flowers, did not get the days spent, respected the soil, loved the wind, desired the rain, took up life as a life of flowers, plants, vines, coloured birds, sweating, etc., and thought of it as a life mixed with nature. Since literature was a part of the culture, the Sangam poets were rich in grammar and literary richness in ancient literature, which is the best literature that compiles the culture in written form, by organizing it into biographical data that describes the culture of the people. Therefore, by painting the virtues and civilizational character of the ancient Tamil people in their songs without transgressing tradition and unchanging from tradition, the worldly, the psychology, the well-known ones of the values of life in order to be spoken in a sequence, and the moral ideas to be lived in a manner that is to be lived in the praise of the good, the reproach the unwanted ones, and the society which has developed as an expression of the human emotions of the human mind, in the pursuit of the task of the social work of the social and religious human life. A society that has developed as an expression of human consciousness, from the background of religious human life to the equivalent of the fruits of labour in the fulfillment of social duty, still possesses the primitive elements of the various forms of worship, customs, beliefs, and rituals that we carry out, and has grown to the level of individual life, such as ethnic life, and has grown into a society, recognizing the antiquity of human worship, and begin to worship God. The purpose of this article is to briefly see how the man who started the inner fine arts by realizing it by the heart and receiving many benefits from rituals by worshipping the deity and learning many benefits from the songs of ancient Tamil literature has been studied

Drug-induced Osteoporosis

https://scholarlycommons.henryford.com/obmdsymp2020/1001/thumbnail.jp

A REVIEW ON VOICE ACTIVITY DETECTION AND MEL-FREQUENCY CEPSTRAL COEFFICIENTS FOR SPEAKER RECOGNITION (TREND ANALYSIS)

ABSTRACTObjective: The objective of this review article is to give a complete review of various techniques that are used for speech recognition purposes overtwo decades.Methods: VAD-Voice Activity Detection, SAD-Speech Activity Detection techniques are discussed that are used to distinguish voiced from unvoicedsignals and MFCC- Mel Frequency Cepstral Coefficient technique is discussed which detects specific features.Results: The review results show that research in MFCC has been dominant in signal processing in comparison to VAD and other existing techniques.Conclusion: A comparison of different speaker recognition techniques that were used previously were discussed and those in current research werealso discussed and a clear idea of the better technique was identified through the review of multiple literature for over two decades.Keywords: Cepstral analysis, Mel-frequency cepstral coefficients, signal processing, speaker recognition, voice activity detection

Salivary Progesterone as a Biochemical Marker to Predict preterm birth in Asymptomatic High Risk Women

This prospective study was conducted in 90 asymptomatic high risk women attending antenatal clinic in the Institute of Obstetrics and Gynaecology from January 2015 to March 2016. AIM AND OBJECTIVES: 1. To evaluate salivary progesterone as a marker of preterm birth. 2. To compare it with transvaginal cervical length in predicting preterm birth. MATERIALS AND METHODS: The information pertaining to the study like age, height, weight, BMI, socioeconomic status, occupational status, passive smoking, gestational age at delivery, NICU admission and neonatal mortality were collected from the 90 enrolled AN mothers. Two saliva samples were collected at 24 to 28 weeks and then at 29 to 32 weeks, simultaneously with transvaginal cervical length measurement. They were followed throughout the antenatal period for development of exclusion criteria. Details about gestational age at delivery, birth weight, NICU admission and neonatal mortality were collected. RESULTS: Sensitivity and specificity of salivary progesterone in predicting preterm labour, when done between 24 to 28 weeks was 100% and 94.2% respectively when the criterion was set as ≤ 3903pg/ml. The same when repeated between 29 to 32 weeks, sensitivity and specificity was 100% and 100% respectively when the criterion was set as ≤ 2975pg/ml. Sensitivity and specificity for trannsvaginal cervical length in predicting preterm labour was 91.7% and 95.7% respectively at 24 to 28 weeks when the criterion was set as ≤ 3.1cm and 100% and 98.6% respectively, when done at 29 to 32 weeks, and the criterion set as ≤ 2.9cm. There is increased incidence of preterm labour in group with history of passive smoking (66.7% in preterm group and 34.8% in term group. Neonates belonging to preterm birth group had higher incidence of NICU admissions (13.6% in preterm group and 6.2% in term group). Incidence of neonatal mortality is 1.2% in the pretem group which is significant (P=0.016). CONCLUSION: Salivary progesterone levels was a better predictor of preterm labour when compared to transvaginal cervical length as it has better sensitivity and specificity, non invasive, easier sample collection and does not need technical expertise. Salivary progesterone estimation done at 29 to 32 weeks has a better sensitivity and specificity than at 24 to 28 weeks