Optimality via generalized approximate convexity and quasiefficiency

In this article, we look beyond convexity and introduce the four new classes of functions, namely, approximate pseudoconvex functions of type I and type II and approximate quasiconvex functions of type I and type II. Suitable examples illustrating the non emptiness of the newly defined classes and distinguishing them from the existing classical notions of pseudoconvexity and quasiconvexity are provided. These newly defined concepts are then employed to establish sufficient optimality conditions for the quasi efficient solutions of a vector optimization problem.     

Raman spectroscopic study of medieval Indian art of 17th century

We report the first Raman spectroscopic investigations of medieval Indian art of 17th century. Three miniature paintings, belonging to Mogul and Rajput schools from the collections of the Madras Museum, were investigated by micro‐Raman spectroscopy using different excitation wavelengths. Many areas in the paintings exhibited rich spectra containing several intense Raman bands. The Raman bands were assigned on the basis of the reported reference spectra of the pigments. Evidences for the presence of massicot, red‐lead, lead‐white, vermilion, litharge, Indian yellow and anatase are found. In addition, tentative assignments of some of the Raman bands to atacamite and orpiment are also made. The present studies suggest that several mineral‐based unique pigments were popular among the Indian artists of this period. Copyright © 2010 John Wiley & Sons, Ltd.     

Chemical investigation of Cannabis sativa leading to the discovery of a prenylspirodinone with anti-microbial potential

The discovery of a new spiran based natural product, prenylspirodinone (1), together with six known cannabinoids (2–7) from the leaves of Cannabis sativa (Marijuana) is reported. All compounds were screened for antifungal and antibacterial activity against a panel of microbial pathogens and exhibited antimicrobial activities with IC₅₀ values ranging from 2.6 to 49.6?µM. Compound 2, a propyl substituted cannabidiol, was determined to be a specific inhibitor against C. albicans (IC₅₀ 11.9?µM) and can be considered as a new lead against Candidiasis.     

Greener approach toward the generation of dimedone derivatives

The use of dimedone in green chemistry has been described for the synthesis of selective heterocyclic motifs which are both pharmacologically and industrially important. The objective of this review is to summarize some of the selected recent advances of dimedone in the synthesis of organic compounds utilizing green chemistry procedures.     

Effect of loop orientation on quadruplex-TMPyP4 interaction

G-quadruplexes are believed to be potential targets for therapeutic intervention and this has resulted in designing of various quadruplex interacting ligands. Moreover, reports about existence of quadruplex forming sequences across the genome have propelled greater interest in understanding their interaction with small molecules. An intramolecular quadruplex sequence can adopt different conformations, owing to different orientation of loops in the structure. The differences in the loop orientation can affect their molecular recognition. Herein, we have studied the interaction of 5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H, 23H-porphine (TMPyP4), a well-known G quadruplex binding ligand with three DNA quadruplexes differing in loop orientations. Results obtained from UV, ITC, and SPR studies have coherently revealed that the TMPyP4 molecule shows preferential binding to parallel G-quadruplex ( c-myc and c-kit) over its antiparallel counterpart (human telomeric). The binding affinity for parallel quadruplex was (10(7)) 1 order of magnitude higher than that for antiparallel DNA quadruplex (10 ). The study shows two binding modes, stronger binding (10(7)) of TMPyP4 involving end stacking and a weaker external binding (10 ), while TMPyP4 shows only one binding mode with duplex with a binding affinity of the order of 10(6). Overall, the study emphasizes that differences in the loop orientation give rise to different conformations of quadruplex, which in turn govern its binding to small molecules, and thereby play a pivotal role in molecular recognition.     

Polyaniline based nucleic acid sensor

Twenty-bases long NH2-modified DNA and PNA probes specific to a pathogen (Mycobacterium tuberculosis) were covalently immobilized onto a polyaniline (PANI)/Au electrode to detect nucleic acid hybridization with complementary, one-base mismatch and noncomplementary targets within 30 s using Methylene Blue. The PNA-PANI/Au electrode exhibits improved specificity (1000 times) and detection limit (0.125 x 10(-18) M) as compared to that of the DNA-PANI/Au electrode (2.5 x 10(-18) M). These PNA-PANI/Au electrodes can be utilized for detection of hybridization with the complementary sequence in 5 min sonicated M. tuberculosis genomic DNA within 1 min of hybridization time. These DNA-PANI/Au and PNA-PANI/Au electrodes can be used 6-7 and 13-15 times, respectively.     

Nucleic acid sensor for M. tuberculosis detection based on surface plasmon resonance

Cysteine modified NH(2)-end peptide nucleic acid (PNA) (24-mer) probe and 5'-thiol end labeled deoxyribonucleic acid (DNA) probes specific to Mycobacterium tuberculosis have been immobilized onto BK-7 gold coated glass plates for the detection of complementary, one-base mismatch, non-complementary targets and complementary target sequence in genomic DNA of Mycobacterium tuberculosis using a surface plasmon resonance (SPR) technique. The DNA/Au and PNA/Au bio-electrodes have been characterized using contact angle, atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetric (CV) techniques, respectively. It is revealed that there is a 252 millidegrees SPR angle change in the case of PNA immobilization and 205 millidegrees for DNA immobilization, indicating increased amount of immobilized PNA molecules. Hybridization studies reveal that there is no binding of the non-complementary target to DNA/Au and PNA/Au electrode. Compared to the DNA/Au bioelectrode, PNA/Au electrode has been found to be more efficient for detection of one-base mismatch sequence. The PNA/Au bioelectrode shows better detection limit (1.0 ng ml(-1)) over the DNA-Au bioelectrode (3.0 ng ml(-1)). The values of the association (k(a)) and dissociation rate constant (k(d)) for the complementary sequence in case of the PNA/Au bioelectrode have been estimated as 8.5 x 10(4) m(-1) s(-1) and 3.6 x 10(-3) s(-1), respectively.     

Visible Light Mediated Halogen Atom Transfer to Access Polyhalogenated and Deuterated Lactams from Alkyl Halides

A visible light mediated protocol for the synthesis of polyhalogenated and deuterated δ- and γ-lactams from readily available alkyl halides is reported. The reaction involves the generation of haloalkyl radicals through halogen atom transfer (XAT) and subsequent arylalkylation of olefins to afford dihydroisoquinolinones and oxindoles. This new XAT protocol exhibits wide scope under mild conditions and enables access to new halogenated chemical space.