Self-microemulsifying smaller molecular volume oil (Capmul MCM) using non-ionic surfactants: a delivery system for poorly water-soluble drug

The main purpose of this work is to formulate self-microemulsifying drug delivery system (SMEDDS) using smaller molecular oil with Atorvastatin calcium as a model drug. Solubility of the selected drug was accessed in oils and surfactants. Percent transmittance (%T) test study was performed to identify the efficient self-microemulsifying formulations. Those formulations which showed higher value for %T were evaluated for droplet size, polydispersity index, ζ potential, refractive index and cloud point measurement. Effect of drug loading on droplet size, increasing dilution in different media, thermodynamic stability and in vitro dissolution was performed to observe the performance of the selected formulation. Further cytotoxicity and permeation enhancement studies were carried out on Caco2 cell lines. Of all the oils accessed for drug solubility, Capmul MCM showed higher solubility capacity for Atorvastatin calcium. Capmul MCM was better microemulsified using combination of Tween 20 and Labrasol surfactant. Droplet size was as low as 86.93?nm with polydispersity index and ζ potential at 0.195?±?0.011 and -7.27?±?3.11 mV respectively. The selected undiluted formulation showed refractive index values ranging from 1.40 to 1.47 indicating the isotropicity of the formulation. The selected formulation was robust to dilution in different media and thermodynamically stable. Dissolution profile was enhanced for the selected drug as compared to marketed formulation with t85% and DE values at 10?min and 80.15 respectively. Also cytotoxicity measurement showed minimum effect with good permeation enhancing capacity. Thus our study demonstrates the use of smaller molecular oil (Capmul MCM) for developing self-microemulsifying drug delivery system for better in vitro and in vivo performance.     

High pressure study of n-propylbenzene oxidation

The high pressure and temperature kinetics of n-propylbenzene oxidation were investigated in the High Pressure Single Pulse Shock Tube at University of Illinois at Chicago. Experiments were performed at nominal reflected shock pressures of 25 and 50 atm, with the temperatures ranging from 838 to 1669 K and for an equivalence ratio of 0.5–1.9. A variety of stable species ranging from aliphatic hydrocarbons to single ring and polycyclic aromatic hydrocarbons were sampled from the shock tube and analyzed using standard gas chromatographic techniques.Within the range of this experimental study, the fuel decay was seen to be insensitive to the changes in pressure. The formation of the intermediates from the fuel were influenced by the concentration of the oxidizer. A detailed chemical kinetic model was developed to simulate the stable species profiles as obtained from the high pressure oxidation experiments. The model provides a satisfactory fit for the consumption of the fuel, oxidizer and the formation of the major aliphatic, mono-aromatic and polycyclic aromatic hydrocarbons.     

Illumination normalized based technique for retinal blood vessel segmentation

The Retinal image carries important information about the health of the sensory part of the visual system. In this paper, a new approach is suggested by utilizing the homomorphic filter integrated with Contrast limited adaptive histogram equalization (CLAHE) method for the illumination normalization and contrast enhancement of the retinal images. Then segmentation is done through several steps by using the existing methods such as morphological filtering, a second derivative operator that is followed by a final morphological filtering stage and hysteresis thresholding. The suggested method is verified on DRIVE and CHASE‐DB1 databases and has average accuracy of 72.03% and 64.54%, accordingly. The obtained results demonstrate that the proposed approaches achieve higher accuracy than the traditional method. The suggested approach not only contributes to the successful result, but also minimizes the computing time.     

Synthesis and characterization of aniline-doped mixed copolymer resins. II

Copolymer resins were synthesized by the mixed condensation of resorcinol–CH₂O, resorcinol–aniline–CH₂O, resorcinol–aniline–thiourea–CH₂O, and resorcinol–aniline–urea–thiourea–CH₂O with a view to develop synthetic resins having improved properties and performance like toughness, mechanical properties, thermal resistance, chemical inertness, and adhesion. The resins were characterized by IR and TG analyses. The thermal analysis showed that the mixed copolymer resins have significantly better thermal stability than that of the simple phenol–CH₂O, aniline–CH₂O, urea–CH₂O, and thiourea–CH₂O resins. At 600°C, only a 50% weight loss is observed, and even at 800°C, the weight loss is about 70%. The resins are insoluble in most of the organic solvents including DMSO-d₆. They too are unaffected by diluted HNO₃, but dissolve in concentrated HNO₃. © 1996 John Wiley & Sons, Inc.     

Solubility studies and thermophysical properties of uranium–neodymium mixed oxides system

Uranium–neodymium mixed oxides (U_1−yNd_y)O_2±x (y=0.2–0.85) were prepared by citrate gel-combustion and characterized by XRD. Single phase fluorite structure was observed up to y=0.80. For solid solutions with y>0.80 additional lines pertaining to hexagonal neodymium oxide were observed. Lattice thermal expansion of these samples was investigated by using high temperature X-ray diffraction (HTXRD). The coefficients of thermal expansion for (U_1−yNd_y)O_2±x for y=0.2, 0.4, 0.6, and 0.8 in the temperature range 298–1973 K were found to be 16.46, 16.64, 16.79, and 16.89×10⁻⁶ K⁻¹, respectively. Heat capacity and enthalpy increment measurements were carried out by using DSC and drop calorimetry in the temperature range 298–800 K and 800–1800 K respectively. The C_p,m values at 298 K for (U_1−yLa_y)O_2±x (y=0.2, 0.4, 0.6, and 0.8) are 63.4, 64.3, 61.8, and 58.9 J K⁻¹ mol⁻¹ respectively.     

Low–Temperature Hydrogen Sensors Based on Au Nanoclusters and Schottky Contacts on ZnO Films Deposited by Pulsed Laser Deposition on Si and SiO2 Substrates

Unintentionally doped n-type ZnO thin films deposited on Si and SiO₂ substrates by pulsed laser deposition (PLD) techniques, were functionalized as H₂ gas sensors by a) incorporating Au nanoclusters in the surface, and b) developing Au Schottky diodes on ZnO. The influence of the catalytic action of the Au nanoclusters on the sensing properties of the devices was examined and found to provide faster response times at a reduced working temperature of 150 degC. The field-assisted sensing of the Au Schottky diodes demonstrated for the first time in this system, a more dramatic reduction in the working temperature of the sensor to nearly room temperature     

An optimal control analysis for baseflow externalities in an interconnected lake–aquifer system

Groundwater resources play a vital role in regional growth and development. From a sustainability viewpoint, it is, however, imperative to ensure that groundwater extractions do not lead to deleterious environmental consequences. The interconnections between groundwater in the aquifers and surface water bodies are increasingly being recognized in recent times and groundwater discharges to surface water bodies are critical to maintain water levels and water quality during summer months and periods of drought. Excessive groundwater withdrawals can cause water levels in streams and lakes to drop below unacceptable levels. This phenomenon is referred to as baseflow externality in this study. The primary goal of this investigation was to develop a mathematical model useful to assess policy options pertaining to groundwater withdrawals considering baseflow externalities. The model was used to evaluate five wide-ranging policy options that emphasize economic gains and ecological impacts to different levels. The weak sustainability policy option represents a reasonable compromise and identifies groundwater pumping that maximizes economic benefits while maintaining acceptable water levels in an interconnected lake. However, the implementation success of this approach hinges on achieving consensus among stakeholders and the ability to find reliable additional water supplies at the end of the planning period. The developed model can be a useful tool for facilitating stakeholder discussions that foster participatory groundwater management.