Study of Optical Properties of <Emphasis Type="Italic">Macrophomina phaseolina</Emphasis> Impregnated Sol-gel Derived Silica Matrices

In the present frame of work, Macrophomina phaseolina is encapsulated in silica matrices at various concentrations by low temperature sol-gel technique using tetraethylorthosilicate (TEOS) as precursor. The optical and photophysical properties of these samples have been studied by second harmonics of Nd:YAG laser at 532 nm. UV-visible absorption spectra of samples have been recorded and it is found that the absorption increases with increase in concentration of fungus. Further, a decrease in output transmission intensity of the laser has been observed with increase in fungus concentration. The temporal response of these samples has also been examined. The results show that the fungus concentration can be measured within ∼15–20 min. This method of optical sensing of fungus in test sample is faster than other techniques, such as the conventional colorimetric method which takes about 1 h.     

A comparative study of electronic structure and bonding in transition metal monocarbides

The structural, electronic, elastic and bonding properties of four transition metal carbides, ScC, YC (group III), VC and NbC (group V), have been investigated systematically using the first principles density functional theory (DFT). The full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange correlation has been used for the calculation of the total energy. The ground state properties, such as equilibrium lattice constant, bulk modulus, are computed and compared with theoretical and experimental data. The electronic and bonding patterns of the two groups of compounds have been analyzed quantitatively and compared with the available data. It is clear from band structures that all the four transition metal monocarbides are metallic in nature. Analysis of elastic constants reveals that the carbides of group III are ductile in nature while those of group V are brittle.     

Explicit determination of certain minimal constabelian codes

Constabelian codes can be viewed as ideals in twisted group algebras over finite fields. In this paper we study decomposition of semisimple twisted group algebras of finite abelian groups and prove results regarding complete determination of a full set of primitive orthogonal idempotents in such algebras. We also explicitly determine complete sets of primitive orthogonal idempotents of twisted group algebras of finite cyclic and abelian p-groups. We also describe methods of determining complete set of primitive idempotents of abelian groups whose orders are divisible by more than one prime and give concrete (numerical) examples of minimal constabelian codes, illustrating the above mentioned results.     

Palladium Aryl Sulfonate Phosphine Catalysts for the Copolymerization of Acrylates with Ethene

The reaction of 2‐[bis(2‐methoxy‐phenyl)phosphanyl]‐4‐methyl‐benzenesulfonic acid (a) and 2‐[bis(2′,6′‐dimethoxybiphenyl‐2‐yl)phosphanyl]benzenesulfonic acid (b) with dimethyl(N,N,N′,N′‐tetramethylethylenediamine)‐palladium(II) (PdMe₂(TMEDA)) leads to the formation of TMEDA bridged palladium based polymerization catalysts ( 1a and 1b ). Upon reaction with pyridine, two mononuclear catalysts are formed ( 2a and 2b ). These catalysts are able to homopolymerize ethylene and also copolymerize ethylene with acrylates or with norbornenes. With ligand b , high molecular weight polymers are formed in high yields, but higher comonomer incorporations are obtained with ligand a .

     

Simultaneous quantification of abemaciclib and letrozole in rat plasma: method development,validation and pharmacokinetic application

Treatment through a combination of drugs involving cyclin D-dependent kinase inhibitors like abemaciclib and aromatase inhibitor like letrozole proved to be a potential therapeutic regimen and first-line treatment in estrogen receptor-positive breast cancer. In this study, we developed a simple and simultaneous RP-HPLC bioanalytical method for quantifying abemaciclib and letrozole in rat plasma. Abemaciclib and letrozole were separated on Zorbax Eclipse C₁₈ column employing a gradient elution method comprising 10 mM ammonium acetate (pH 5) and acetonitrile as mobile phase. The method was found to have acceptable selectivity, accuracy (97.20–118.17%), precision (1.10–9.39%) and stability in the validation experiment performed as per the US Food and Drug Administration guidelines. The method sensitivity was low at a concentration level of 100 ng/ml. The applicability of the method has been verified through a single-dose oral pharmacokinetic study in rat. The developed method will be useful to quantitate the analytes in rat plasma samples of different preclinical studies including their pharmacokinetic drug–drug interactions in the future. To date, no method has been reported for the quantification of abemaciclib and letrozole simultaneously in any type of biological matrices. Therefore, this study makes a definite significant contribution in the field of bioanalytical research.     

Modification of Dietary Fiber Psyllium with Poly(vinyl pyrrolidone) through Network Formation for Use in Slow Drug Delivery Application

In view of the pharmacological importance of dietary fibre, psyllium, to cure the constipation and diverticulitis, in the present study, an attempt has been made to modify psyllium polysaccharide with PVP to develop the hydrogel meant for slow and controlled drug delivery systems. The polymer was characterized by SEMs, FTIR, XRD, TGA and swelling studies. Swelling of hydrogels and drug (ciprofloxacin) release profile from the drug loaded hydrogels were determined for the evaluation of the swelling/release mechanism. Biomedical properties; biocompatibility and mucoadhesion of the hydrogels, were also studied. Swelling of the hydrogels and release of drugs from drug loaded hydrogels occurred through non-Fickian diffusion mechanism. Here it is pertinent to mention that both psyllium husk polysaccharide and antibiotic drug ciprofloxacin are used for gastrointestinal tract (GIT) problem, especially in case of diverticulitis. Hence, degradation of the polymer matrix and release of drug may exert the synergic effect and the present drug delivery system may act with enhanced potential.     

Twisted amides inferred from QSAR analysis of hydrophobicity and electronic effects on the affinity of fluoroaromatic inhibitors of carbonic anhydrase.

QSAR has been used to elucidate the origin of the hydrophobicity and binding affinity of a small library of fluoroaromatic inhibitors of F131V carbonic anhydrase II. Our analysis predicted the presence of a twisted amide conformation for several bound inhibitors, which we confirmed crystallographically. We also determined that the hydrophobicity of the inhibitors as a whole results from the fragment hydrophobicities of their fluorobenzyl rings, corrected for field effects and the presence of an intramolecular F.H contact in solution. The loss of this interaction on binding to the enzyme makes the affinity sensitive to the same terms, but with the opposite dependence on the F.H contact. In the case of the four inhibitors bound as twisted amides, this F.H contact must be retained to some extent in the bound state in order for their affinities to be consistent with our QSAR analysis of the entire set of 17 molecules.     

A simplex algorithm for piecewise-linear fractional programming problems

Generalizations of the well-known simplex method for linear programming are available to solve the piecewise linear programming problem and the linear fractional programming problem. In this paper we consider a further generalization of the simplex method to solve piecewise linear fractional programming problems unifying the simplex method for linear programs, piecewise linear programs, and the linear fractional programs. Computational results are presented to obtain further insights into the behavior of the algorithm on random test problems.     

Halide coordination of perhalocyclohexasilane Si6X12 (X=Cl or Br)

The addition of halide anions (X' = Cl(-), Br(-), or I(-)) to perhalocyclohexasilane Si(6)X(12) (X = Cl or Br) led to the formation of complexes comprising [Si(6)X(12)X'(2)](2-) dianions. An upfield shift in the (29)Si NMR spectra was noted upon coordination, and structural determination by X-ray crystallography showed that the dianions adopt an "inverse sandwich" structure where the six cyclic silicon atoms form a planar hexagon with the two halide anions X' located on the 6-fold axis equally disposed above and below the plane of the Si(6) ring. Additionally, these apical X' atoms are within the van der Waals bonding distance to the silicon ring atoms, indicating a strong interaction between X' and silicon atoms. These results detail crystallographic variations within the halogen series providing further insight into the nature of the Lewis acid sites above and below the Si(6)X(12) ring, where interactions with hard Lewis bases such as halide anions are observed. Interestingly, the stereochemistry of the silicon atoms in [Si(6)X(12)X'(2)](2-) is not affected much by the size or electronegativity of the halogen atoms.     

Palladium acetate assisted synthesis of five-membered N-polyheterocycles

Abstract

The metal-assisted synthesis of heterocyclic compounds is known to be one of the extremely developing as well as significant concepts of organic chemistry. Because of their expensive, complex working of the instrument and difficult procedures, the methodologies used earlier for the heterocycle synthesis were less amicable to the researchers. The Pd(OAc)₂-mediated cyclic reactions have been recognized to be very effective for both the stereoselective as well as regioselective formation of the 5-membered N-bearing heterocyclic compounds. The different uses of palladium acetate, as a catalyst in the formation of 5-membered N-containing polyheterocycles, are covered in this review article.