Structural confirmation of regioisomers of Lopinavir impurities using MS and gradient COSY (1H and 13C NMR assignment of Lopinavir impurities)

We report the complete (1)H and (13)C NMR assignment of impurities of six Lopinavir (2S)-N-[(2S, 4S, 5S)-5-{[2-(2,6-dimethylphenoxy)acetyl]amino}-4-hydroxy-1,6-diphenyl hexan-2-yl]-3-methyl-2-(2-oxo-1,3-diazinan-1-yl)butan- amide. Two of the impurities are regioisomers and GCOSY used to differentiate the two structures. The spectral assignments for all six impurities were achieved by concerted application of one and two-dimensional NMR techniques ((1)H NMR, (13)C NMR, DEPT, GCOSY, GHSQC and GHMBC).     

Biological evaluation of redox stable cisplatin/Cu(II)-DNA adducts as potential anticancer agents

A series of non-enolizable β-diketonate-based copper(II) complexes with LCuCl₂ [L = Knoevenagel condensates of curcumin (Salcimine) and methylacetoacetate (SalMaA)-based Schiff bases] chromospheres as functional models of chemotherapy drug cisplatin were investigated for their covalent interaction with herring sperm DNA. The synthesis and structural characterization of 1a and 1b have been reported in our previous article. However, their DNA interactions and cytotoxicity properties were not studied. These analyses have been carried out mainly through electrochemical techniques supplemented with spectral, relative viscosity, gel electrophoresis techniques, and AGS cancer cells using MTT assay. The cytotoxic activities of the ligand, curcumin-based copper complex, and cisplatin were tested against the AGS cancer cell line under similar experimental conditions showing that the complex exhibited cancer cell inhibitory rate closer to cisplatin even at low concentration. This was also seen in the docking of the Cu-complex onto a rich guanine B-DNA decamer, where a Cu–N3_(guanine) interaction instead of Pt-N7 as cisplatin is detected. The obtained results in this study prove that these complexes could be a promising substitute for cisplatin as a new family of non-platinum-based anticancer metallo-drugs after in vivo tests on animal models.     

Significance of Stefan blowing effect on flow and heat transfer of Casson nanofluid over a moving thin needle

The current mathematical model explains the influence of non-linear thermal radiation on the Casson liquid flow over a moving thin needle by considering Buongiorno's nanofluid model.The influences of Stefan blowing, Dufour and Soret effects are also considered in the model. The equations which represent the described flow pattern are reduced to ordinary differential equations(ODEs) by using apt similarity transformations and then they are numerically solved with Runge–Kutta-Fehlberg's fourth fifth-order method(RKF-45) with shooting process. The impacts of pertinent parameters on thermal, mass and velocity curves are deliberated graphically.Skin friction, rate of heat and mass transfer are also discussed graphically. Results reveal that, the increase in values of Brownian motion, thermophoresis, Dufour number, heating and radiative parameters improves the heat transfer. The increasing values of the Schmidt number deteriorates the mass transfer but a converse trend is seen for increasing values of the Soret number. Finally,the escalating values of the radiative parameter decays the rate of heat transfer.     

An automated high precision calorimeter for the temperature range 200 K–400 K. Part II. Design of temperature controllers

The design and construction of precision temperature controllers, capable of tracking the temperature of the samples to within 1 mK for ramp heating rates from 0.05 to 10 K per hour, are discussed. A tutorial section on the evolution of the control loop configuration is first given. This is followed by an outline of the refinements of the basic control loop desirable in the actual implementation of the electronic controller. The novel features of the present system and its performance are then briefly discussed. Finally the inadequacy of the conventional PID controllers for this application, the estimation of the time constants of the physical system needed in the design of the electronic controllers and the pitfalls in using a simple model of the heater plus thermometer assembly with a single pole are also discussed.     

The isolation,identification and synthesis of 3,6-dimethylheptan-2,4-dione,a pheromone of the mushroom fly, Megaselia halterata (diptera:phoridae)

A pheromone of the female mushroom fly, Megaselia halterata, has been identified as 3,6-dimethylheptan-2,4-dione which exists as a mixture of keto and enol forms.     

Synthetic methodology for cyclodextrin-dipyrromethane conjugates

A new method for synthesis for cyclodextrin-dipyromethane conjugates consisting of a reaction between cyclodextrin monoaldehyde and pyrrole is presented here. Resulting dipyromethane is characterized by spectroscopic and computational methods.     

Transport properties of alternative fuel microemulsions based on sugar surfactant

Electrical conductivity of fuel microemulsion composed of diesel, pentanol, water, and sucrose laurate as surfactant was investigated over a wide range of water contents varying from 0 to 90?wt% and temperature varying from 10°C to 50°C. Conductivity measurements were performed on samples, the composition of which lie along the one-phase channel using a conductivity meter. Activation energy of conduction flow was evaluated. The hydrodynamic radius as a function of temperature in the aqueous phase-rich region (90?wt%) was measured using the dynamic light scattering (DLS) method. The microstructure of the microemulsion was further investigated by NMR diffusometry by which the self-diffusion coefficients for water were determined at 25°C. Electrical conductivity increases with water content up to 40?wt% and the percolation threshold was observed, and then stabilizes between 40 and 80?wt% then decreases. Percolation threshold temperature at constant composition was monitored as 36°C for water contents below 80?wt% and as 34°C for water contents above that. As predicted by the conductivity measurements, the determined self-diffusion coefficients of water confirmed the structural transition from discrete W/O droplets to bi-continuous phase and finally to O/W droplet microemulsion.     

Permeabilization of Kluyveromyces marxianus with Mild Detergent for Whey Lactose Hydrolysis and Augmentation of Mixed Culture

Cheese whey is a by-product of cheese-manufacturing industries, and the utilization of whey is a challenging problem either to use it or dispose it, because only few microorganisms can metabolize the whey lactose. Enzymatic hydrolysis of whey lactose to glucose and galactose by β-galactosidase is the approach for biotechnological application. Kluyveromyces marxianus cells were permeabilized with non-toxic, biodegradable, anionic detergent N-lauroyl sarcosine (N-LS) for the enzyme activity. The permeabilization process parameters (N-LS concentration, solvent volume, temperature and incubation time) were optimized. The maximum β-galactosidase activity of 1,220 IU/g dry weight was obtained using permeabilized cells under optimized conditions. Moreover, viability of the permeabilized cells was also evaluated, which showed that cells were alive; however, viability was reduced by two log cycles. The permeabilized cells were evaluated for whey lactose hydrolysis. The maximum lactose hydrolysis of 91 % was observed with 600 mg (dry cell weight/100 mL) in whey powder (5 % w/v) solution at 180-min incubation, pH 6.5 and 30 °C. Further, the hydrolyzed whey was evaluated for amelioration of growth of non-lactose-consuming yeast Saccharomyces cerevisiae. S. cerevisiae was able to grow in hydrolyzed whey simultaneously with K. marxianus. The study confirmed that N-LS could be used to permeabilize K. marxianus cells to make available the enzyme activity.     

One-pot multi-component synthesis of novel ethyl-2-(3-((2-(4-(4-aryl)thiazol-2-yl)hydrazono)methyl)-4-hydroxy/isobutoxyphenyl)-4-methylthiazole-5-carboxylate derivatives and evaluation of their in vitro antimicrobial activity

A novel series of ethyl-2-(3-((2-(4-(4-aryl)thiazol-2-yl)hydrazono)methyl)-4-hydroxy/isobutoxyphenyl)-4-methylthiazole-5-carboxylate derivatives ( 4a-f and 5a-f ) were synthesized by employing one-pot multi-component approach involving ethyl 2-(3-formyl-4-oxy/isobutoxyphenyl)-4-methylthiazole-5-carboxylate, thiosemicarbazide and various phenacyl bromides/3-(2-bromoacetyl)-2H-chromen-2-one/2-(2-bromoacetyl)-3H-benzo[f]chromen-3-onein ethanol in the presence of catalytic amount of acetic acid. The structures of all the synthesized compounds were confirmed with spectral analysis, ie, IR, 1H NMR, 13C NMR and mass spectrometry, and all the compounds were screened for their in vitro antimicrobial activity.