Spray drying of drug-swellable dispersant suspensions for preparation of fast-dissolving,high drug-loaded,surfactant-free nanocomposites

Bioavailability of a poorly soluble drug can be improved by preparing a drug nanosuspension and subsequently drying it into nanocomposite microparticles (NCMPs). Unfortunately, drug nanoparticles aggregate during milling and drying, causing incomplete recovery and slow dissolution. The aim of this study is to investigate the impact of various classes of dispersants on drug dissolution from drug NCMPs, with the ultimate goal of enhancing the bioavailability of poorly water-soluble drugs via high drug nanoparticle loaded, surfactant-free NCMPs. Precursor suspensions of griseofulvin (GF, model drug) nanoparticles in the presence of various dispersants were prepared via wet stirred media milling and spray dried to form the NCMPs. Hydroxypropyl cellulose (HPC, polymer) alone and with sodium dodecyl sulfate (SDS, surfactant) was used as a base-line stabilizer/dispersant during milling. Two swellable crosslinked polymers, croscarmellose sodium (CCS) and sodium starch glycolate (SSG), and a conventional soluble matrix former, Mannitol, were used in addition to HPC. Besides being used as-received, CCS was also wet co-milled with GF for two different durations to examine the impact of CCS particle size. Laser diffraction, scanning electron microscopy, powder X-ray diffraction (XRD), UV spectroscopy, NCMP redispersion and dissolution tests were used for characterization. The results show that incorporation of CCS/SSG, preferably wet-milled to a wide particle size distribution, into the spray-dried NCMPs resulted in fast release and dispersion of drug nanoparticle clusters. The swellable dispersants were superior to Mannitol in dissolution enhancement, and could achieve fast release comparable to SDS, demonstrating the feasibility of spray drying to prepare high drug-loaded, surfactant-free nanocomposites.     

Microwave‐assisted polymerization: Inert addition and surface coating of superabsorbent polymer for improved physical properties

Two different polymerization techniques, microwave‐assisted polymerization and free radical solution polymerization, were utilized in the syntheses of superabsorbent polymers with varying amounts of acrylic acid (31–50%). Degrees of neutralization were in the range of 68–80 mol %, and clay level was varied between 0 and 5%. The base polymer produced with microwave‐assisted polymerization had higher absorbency under low load (0.3 psi) than those with the free radical solution polymerization. To improve its absorbency under higher loads (0.6 and 0.9 psi), the surface coating step was implemented by using ethylene glycol diglycidyl ether as a surface crosslinking agent. Properties such as capacity, permeability, and absorbency under different loads were tested in 0.9% sodium chloride solution for the base and the surface‐coated polymers. In addition, extractables and residual acrylic acid were measured to determine the reaction's efficiency. In conclusion, surface coating improved polymer properties, and the incorporation of clay imparted permeability to the polymer. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43990.     

Use of tergitol-7 in photogalvanic cell for solar energy conversion and storage: Toluidine blue-glucose system

Photogalvanic effects were studied in a photogalvanic cell containing toluidine blue, glucose and tergitol-7 as a photosensitizer, reductant and surfactant, respectively. The photocurrent and photopotential generated by this system were 70 μA and 315 mV, respectively. The effects of different parameters on the electrical output of the cell were observed. Current/voltage characteristics of the cell have also been studied, and a mechanism has been proposed for the generation of photocurrent in photogalvanic cell.     

COSMO-RS:An ionic liquid prescreening tool for gas hydrate mitigation

Recently ionic liquids(ILs) are introduced as novel dual function gas hydrate inhibitors. However, no desired gas hydrate inhibition has been reported due to poor IL selection and/or tuning method. Trial error as well as selection based on existing literature are the methods currently employed for selecting and/or tuning ILs. These methods are probabilistic, time consuming, expensive and may not result in selecting high performance ILs for gas hydrate mitigation. In this work, COSMO-RS is considered as a prescreening tool of ILs for gas hydrate mitigation by predicting the hydrogen bonding energies(E_(HB)) of studied IL inhibitors and comparing the predicted E_(HB) to the depression temperature(?) and induction time. Results show that, predicted EHBand chain length of ILs strongly relate and significantly affect the gas hydrate inhibition depression temperature but correlate moderately(R = 0.70) with average induction time in literature. It is deduced from the results that, ? increases with increasing IL EHBand/or decreases with increasing chain length. However, the cation–anion pairing of ILs also affects IL gas hydrate inhibition performance. Furthermore, a visual and better understanding of IL/water behavior for gas hydrate inhibition in terms of hydrogen bond donor and acceptor interaction analysis is also presented by determining the sigma profile and sigma potential of studied IL cations and anions used for gas hydrate mitigation for easy IL selection.     

Experimental,CFD simulation and parametric studies on modified solar chimney for building ventilation

The solar chimney is a passive solar system which can be used for enhance the natural ventilation and space conditioning of a building. A solar chimney design is modified and installed at CBRI Roorkee (29.87° N 77.88° E), India. A Computational fluid dynamics (CFD) software is used for prediction of velocity and temperature in Modified solar chimney (MSC) and evaluating the Air Change per hour (ACH), which is validated through experimental and theoretical counterpart and found a good agreement between them. From the result of thermal performance analysis, it is found that MSC generates 2.39–7.13 ACH in experimental room in month of May 2013, when outdoor solar radiation was in the range of 250–612 W/m². Due to this ACH, the room temperature is dropped by 2–4°C as compared to reference room temperature. The parametric study shows that the optimum glass tilt angle estimated by 5 degree for highest performance consideration of MSC. The air gap is optimised by 60 mm and air gap to inlet opening height ratio is optimised by 0.2.     

Design data for solar heating of air Using a Heat Exchange and Storage System

An arrangement for heating with solar energy by means of a heat exchanger and storage coupled to the two water heaters has been described^*. In the present paper, the amount of the heat transferred from water to air in the shell-and-tube heat exchanger and the temperature of the outgoing air have been estimated by considering various parameters, viz. flow rate and temperature of incoming air, temperature of incoming and outgoing water, length and diameter of tubes, etc. Both natural and forced convection mode of heat transfer have been considered.

Under boundary conditions of free convection, heat transfer would be rapid and efficient with a possible reduction in the pipe length. The maximum permissible limit of pressure drop per foot of each tube for pipes of different diameters at different Reynolds numbers has been given.

As conditions of drying vary from material to material, the data presented will help in arriving at the final design of the shell-and-tube heat exchanger to be used in drying a particular material.     

In vitro study of lipid peroxidation and free radical scavenging activity of cow urine

This study represents a comprehensive analysis and scientific validation of our ancient knowledge about the ethnopharmacological aspects of cow urine by measuring the lipid peroxidation, radical scavenging, and level of reduced glutathione and catalase activity. Graded doses of cow urine were administered orally to experimentally treated rats. Results of liver and plasma from experimentally treated rats indicated that cow urine reduced the levels of thiobarbituric acid reactive substance significantly in all the treatments (P < 0.01). In vitro experiments with the liver of control and experimentally treated rats were also carried out against cumene hydroperoxide-induced lipid peroxidation. On LCMS analysis, the antioxidant component of cow urine was identified as uric acid (m/z 169.07). The results demonstrate that the cow urine-mediated induction of antioxidant level controls oxidative damage, even after minimal processing, and thus is indicative of its potential as a viable substitute of synthetic antioxidants.     

Exact Lithologic Boundary Detection Based on Wavelet Transform Analysis and Real-Time Investigation of Facies Discontinuities Using Drilling Data

Abstract

Exact detection of lithologic boundaries is one of the main challenges in exploration, drilling operations, and geology. Investigation of facies discontinuities has been performed using petrophysical data regarding sharp changes along the wellbore. Due to the fact that recorded well logging signals contain lots of high-frequency waves (noise), detection of the layer boundaries comes with some uncertainties that should be eliminated by denoising those signals. Wavelet transform analysis is a good approach to denoise the signals and its ability has been proven in several studies. In this study, implementation of wavelet transform analysis resulted in an innovative approach for exact differentiation of neighborhood lithologic units.

Detection of boundaries between different layers, especially the ones in the vicinity of the reservoir during drilling operations, is one of the crucial issues in petroleum well engineering. This purpose is usually achieved by cutting analysis and geological maps, which are not accurate enough and may cause substantial problems. Unconfined rock compressive strength can be considered as an accurate criterion to detect geological boundaries. In this study, an artificial neural network (ANN) model is developed that can predict the unconfined rock compressive strength of formations being drilled by importing 10 drilling parameters as inputs. Because rock strength will experience sudden changes while entering the next layer, it can be used as a key parameter to determine boundaries.     

Immittance response of CaSnO3 prepared by self-heat-sustained reaction

The potential of CaSnO3 for application as a capacitor component possessing a small temperature coefficient of capacitance has been examined by ac small-signal measurements at elevated temperatures (25–300°C) in the frequency range 5–13 MHz. The samples were synthesized by a novel technique called self-heat-sustained (SHS) reaction. The ac data were acquired for the CaSnO3 samples sintered at various temperatures with varying soak temperatures, T, and some times, t (1200°C T 1600°C 2 h t 48 h). An analysis of the electrical data in more than one complex-plane formalism indicated relaxation processes. The resistance of these sintered samples was dominated by the grain boundaries, and the capacitance exhibited near-linear behavior at elevated temperature for several decades of measurement frequency. The electrical behavior has been correlated with the evolved microstructure in these samples in conjunction with the results obtained in a previous study for solid-state reaction (SSR) derived sintered bodies. The multi-plane analytical criteria provided a meaning for the lumped equivalent circuit representation including the origin and purpose of the contributing elements extracted from each complex plane formalism.