Geometric phase and o-mode blue shift in a chiral anisotropic medium inside a Fabry-P\'erot cavity

Anomalous spectral shift of transmission peaks is observed in a Fabry--P\'erot cavity filled with a chiral anisotropic medium. The effective refractive index value resides out of the interval between the ordinary and the extraordinary refractive indices. The spectral shift is explained by contribution of a geometric phase. The problem is solved analytically using the approximate Jones matrix method, numerically using the accurate Berreman method and geometrically using the generalized Mauguin--Poincar\'e rolling cone method. The $o$-mode blue shift is measured for a 4-methoxybenzylidene-4'-$n$-butylaniline twisted--nematic layer inside the Fabry--P\'erot cavity. The twist is electrically induced due to the homeoplanar--twisted configuration transition in an ionic-surfactant-doped liquid crystal layer. Experimental evidence confirms the validity of the theoretical model.Comment: the text is available both in English (Timofeev2015en.tex) and in Russian (download: other formats - source - Timofeev2015ru.tex, Timofeev2015rus.pdf

Ultrasound Promoted Synthesis of Pyrazolyl / Isoxazolyl Oxadiazoles as Antimicrobials

Azoles are the principal core structures present in natural products and acquired significance due to a wide range of biological properties associated with them. Amongst different azoles, oxadiazole and their derivatives have gained importance as they constitute the structural features of many bioactive compounds. 1,3,4-Oxadiazoles exhibit antibacterial, antifungal, antioxidant, anti-inflammatory, analgesic, anticancer and anticonvulsant properties. In fact, the combination of different heterocyclic units in a molecule may alter the biopotency which can accommodate multiple biological targets. In continuation of our interest in the synthesis of bioactive heterocyclic compounds, we focused our attention to develop some new oxadiazoles under ultrasonication. The work related to these aspects will be presented. © 2020 Author(s).The author G. Yamini is thankful to the University Grants Commission (UGC), New Delhi, for the sanction of UGC-BSR fellowship

Synthesis, Structural Elucidation and Bioassay of Morpholine/Thiomorpholine and Piperidine Containing Oxazoles

The series of novel oxazole derivatives (3-4) have been synthesized. All the entitles compounds were characterized by IR, 1H, 13C NMR, mass spectra. All the lead compounds were tested for antimicrobial activity. The compound 4f having chloro substituent on the aromatic ring displays greater antimicrobial activity particularly against P. aeruginosa and P. crysogenum. © 2020 Author(s).The authors G. Sravya and N. Bakkthavatchala Reddy are thankful to Ural Federal University, Yekaterinburg, Russia for giving postdoctoral fellowship

Synthesis of a New Class of Thiazolyl Morpholines / Thiomorpholines and Evaluation as Antimicrobials

The series of novel thiazole derivatives (4-5) have been synthesized. All the synthesized compounds were characterized by IR, 1H, 13C NMR, mass spectra. All the lead compounds were tested for antimicrobial activity. The compound 5f having chloro substituent on the aromatic ring displays greater antimicrobial activity particularly against P. aeruginosa and P. crysogenum. © 2020 Author(s).The authors G. Sravya and N. Bakkthavatchala Reddy are thankful to Ural Federal University, Yekaterinburg, Russia for giving postdoctoral fellowship

Synthesis of Heteroaryl Urea Derivatives as Antimicrobial Agents

Azoles are prominent scaffolds in the pharmaceutical arena. In fact, medicinal properties of azole and benzazole containing compounds include anticancer, antimicrobial and antioxidant. Some of the drugs Inthomycin C, Oxaprozin, Tiazofurin, Dacarbazine, Tipifarnib, Albendazole, Febendazole, Omeprazole possess azole/benzazole moiety. Realizing the importance of azoles and benzazoles, it is planned to conjugate these two ligands as heteroaryl substituted urea derivatives and to study their antimicrobial activity. The results pertaining to these aspects will be discussed. © 2020 Author(s).The authors K. Narendra Babu and V. Padmavathi are grateful to CSIR (Council of Scientific and Industrial Research), New Delhi for financial assistance under major research project

Phytochemistry and pharmacological activities of the genus Rhynchosia: a comprehensive review

Main conclusion: The genus Rhynchosia is a rich source of natural compounds especially flavonoids and prenylated isoflavonoids. Further experimental studies on Rhynchosia members may be result new and novel secondary metabolites with potent biological activities. Abstract: Traditionally, medicinal plants have played a significant role on human life since ancient days. At present, natural compounds are the major source for the modern drug discovery owing to their therapeutic selectivity, minutest of side effects, inexpensive source and serve as lead molecules for the discovery of new drugs. Rhynchosia species (Fabaceae) are extensively circulated throughout the tropical and subtropical areas around the world. A few plants of this genus were used in traditional medicine for the treatment of various ailments such as antibacterial, antidiabetic, abortifacients, healing of wounds, hepatoprotective, remedial of boils, rheumatic pains and skin infections. The present review compiles traditional uses, isolated chemical compounds and pharmacological activities of Rhynchosia species. So far, in total, seventy-seven compounds were isolated from the genus Rhynchosia, including flavonoids, isoflavonoids, flavan-3-ols, xanthones, biphenyls, simple polyphenols and sterols. It is interesting to note that the genus Rhynchosia is a rich source of C-glycosylflavonoids and prenylated isoflavonoids. Further, phytochemical and pharmacological studies on this genus are required since only few species have been investigated so far. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature

A Review on Magnetron Sputter Coatings

To modify the metal/nonmetal surface properties like hardness, wear and corrosion resistance, surface coating technology is the easiest and inexpensive method. Out of various surface coating methods, the sputter coating technique is one of the prominent methods to improve surface properties. Sputter coating techniques are widely used in aerospace, automobile, solar panels, and various engineering fields to improve the surface properties. The present study focused on various materials used in the sputter coating techniques to develop thin films on various components. The influence of coating materials on hardness, wear and corrosion resistance of the various materials like steels, magnesium and their alloys are also explained in detail in this review. © 2020 Author(s)