Adsorption density of spherical cetyltrimethylammonium bromide (CTAB) micelles at a silica/silicon surface

In situ Fourier transform infrared internal reflection spectroscopy (FT-IR/IRS) was used to calculate the adsorption density values for spherical cetyltrimethylammonium bromide (CTAB) micelles at the silica/silicon (SiO2/Si) surface based on a previously developed adsorption density equation. Recent advances in atomic force microscopy (AFM) imaging methodology have led to the ability to image surface micelles, which was not possible previously. These AFM images have been used to independently calculate adsorption density values through offline fast Fourier transform (FFT) analysis. The adsorption density values measured from in situ FT-IR/IRS spectra and from AFM images showed good agreement and provide further validation of the FT-IR/IRS adsorption density equation in the low concentration range.     

Refugees,Violence and Gender: the Case of Women in the Albert Park Area in Durban,South Africa

Women refugees are affected more by violence than any other female group in the world, before, during and after their forced migration experience, because of patriarchy. This paper examines the violence experienced by female refugees in Albert Park in Durban, South Africa. Albert Park is an area dominated by documented and undocumented foreign migrants from African countries, and since 2008, there have been many reported incidents of violence against refugees. The focus of this study is on intimate partner and public violence, the fear of urban public space and the failure of police protection encountered by female refugees as they have attempted to adapt and adjust in a hostile society, in Albert Park. Domestic tensions have emerged from a reversal of traditional patriarchal gender roles as female refugees have often become heads of households, while men had to tend to domestic chores. Female refugees are also afraid of using public space because they were subject to physical attacks, verbal abuse and sexual harassment from refugees, local people and taxi drivers and conductors. This has been aggravated by the high levels of xenophobic violence in South Africa, tensions between local people and foreigners and the knowledge that police protection is limited.     

In vitro digestibility,pasting, and structural properties of starches from different cereals

Starches isolated from seven different cereals were evaluated for their composition, physicochemical, in vitro digestibility, structural, morphological, and pasting properties. The in vitro starch digestion rate and estimated glycemic index (GI) of cereal starches were evaluated along with the impact of cooking on starch digestion. The cooking of starch slurries increased the rapidly digestible starch content from a range of 34.7–54.4% to a range of 60.5–78.5%. On the basis of hydrolysis index, the GI ranged from 83.6 to 91.8 and after cooking it increased from 95.1 to 98.6 for different cereal starches. Both the swelling power and solubility showed an increasing trend with rising temperature. Paste clarity of starches negatively correlated with fat content. The amylose content of various starches ranged from 17.7 to 24.7% and was negatively correlated to crystalline index (r = -0.975, p ≤ 0.05). XRD pattern revealed A-type pattern of crystalline starch, where crystallinity index ranging between 28.2 to 44.9%. FTIR revealed slight differences among chemical bonding of starches from different cereals. From scanning electron micrograph observations, wheat and barley starch granules proved smoother as compared to other cereal granules. Barley contained the highest (27.5 µm) and rice had the lowest (10.2 µm) size starch granules. The pasting properties were significantly (p ≤ 0.05) different for different cereal starches. Peak, breakdown, and final viscosities were the highest for maize starch (1725, 384, and 2112 mPa.s, respectively), whereas rice and oats exhibited the highest trough and setback viscosities (1420 and 954 mPa.s, respectively).     

Removal of acid red-94 from aqueous solution using sugar cane dust: An agro-industry waste

The feasibility for the removal of Acid Red-94 by sugar cane dust, an agro-industry waste, has been investigated as an alternative for costly adsorbents. The effect of various experimental parameters (adsorbate concentration, solution pH and temperature) on removal of Acid Red-94 has been studied under batch mode of operation. Maximum removal upto 98.73% was achieved at a pH value of 2.0 and temperature 19±0.5 °C in case of 10.0mg/l initial dye concentration. Adsorption kinetics has been described by Lagergren equation and adsorption isotherms by classical Langmuir and Freundlich models. The kinetic studies suggest that the rate of uptake of Acid Red-94 on sugar cane dust was mainly diffusion controlled. Various thermodynamic parameters have been calculated and the temperature dependence indicates exothermic nature of adsorption process. The results indicate that sugar cane dust could be used as an eco-friendly and cost-effective adsorbent in the removal of Acid Red-94 from aqueous solution.     

Mechanism of enhanced photocatalysis with polyhydroxy fullerenes

Polyhydroxy fullerenes (PHF) have been applied for increasing the photocatalytic degradation rate of TiO₂. Scavenging of photo-generated electrons and therefore higher generation of hydroxyl radicals was hypothesized as the mechanism for the observed enhancement. The present study confirms the increase in generation of hydroxyl radicals with electron paramagnetic resonance (EPR) spectroscopy. The concentration of hydroxyl radicals generated by a mixture of TiO₂ and PHF was up to 60% greater than the concentration obtained without PHF. These results are consistent with the observed enhancement in dye degradation and microbial inactivation experiments. The current study also demonstrates that PHF can improve the photocatalytic activity of different TiO₂.     

Mechanistic and Predictive QSAR Analysis of Diverse Molecules to Capture Salient and Hidden Pharmacophores for Anti-Thrombotic Activity

Thrombosis is a life-threatening disease with a high mortality rate in many countries. Even though anti-thrombotic drugs are available, their serious side effects compel the search for safer drugs. In search of a safer anti-thrombotic drug, Quantitative Structure-Activity Relationship (QSAR) could be useful to identify crucial pharmacophoric features. The present work is based on a larger data set comprising 1121 diverse compounds to develop a QSAR model having a balance of acceptable predictive ability (Predictive QSAR) and mechanistic interpretation (Mechanistic QSAR). The developed six parametric model fulfils the recommended values for internal and external validation along with Y-randomization parameters such as R²_tr = 0.831, Q²_LMO = 0.828, R²_ex = 0.783. The present analysis reveals that anti-thrombotic activity is found to be correlated with concealed structural traits such as positively charged ring carbon atoms, specific combination of aromatic Nitrogen and sp2-hybridized carbon atoms, etc. Thus, the model captured reported as well as novel pharmacophoric features. The results of QSAR analysis are further vindicated by reported crystal structures of compounds with factor Xa. The analysis led to the identification of useful novel pharmacophoric features, which could be used for future optimization of lead compounds.     

Gadolinium-doped silica nanoparticles encapsulating indocyanine green for near infrared and magnetic resonance imaging

Clinical applications of the indocyanine green (ICG) dye, the only near infrared (NIR) imaging dye approved by the Food and Drug Administration (FDA) in the USA, are limited due to rapid protein binding, fast clearance, and instability in physiologically relevant conditions. Encapsulating ICG in silica particles can enhance its photostability, minimize photobleaching, increase the signal-to-noise (S/N) ratio and enable in vivo studies. Furthermore, a combined magnetic resonance (MR) and NIR imaging particulate can integrate the advantage of high-resolution 3D anatomical imaging with high-sensitivity deep-tissue in-vivo fluorescent imaging. In this report, a novel synthesis technique that can achieve these goals is presented. A reverse-microemulsion-based synthesis protocol is employed to produce 25 nm ICG-doped silica nanoparticles (NPs). The encapsulation of ICG is achieved by manipulating coulombic attractions with bivalent ions and aminated silanes and carrying out silica synthesis in salt-catalyzed, mildly basic pH conditions using dioctyl sulfosuccinate (AOT)/heptane/water microemulsion system. Furthermore, paramagnetic properties are imparted by chelating paramagnetic Gd to the ICG-doped silica NPs. Aqueous ICG-dye-doped silica NPs show increased photostability (over a week) and minimal photobleaching as compared to the dye alone. The MR and optical imaging capabilities of these particles are demonstrated through phantom, in vitro and in vivo experiments. The described particles have the potential to act as theranostic agents by combining photodynamic therapy through the absorption of NIR irradiated light.     

A review on methodology of artificial roughness used in duct of solar air heaters

In order to enhance rate of heat transfer to flowing air in the duct of a solar air heater, artificially roughened surface of absorber plate is considered to be an effective technique. Investigators reported various roughness geometries in literature for studying heat transfer and friction characteristics of an artificially roughened duct of solar air heaters. In the present paper an attempt has been made to categorize and review the reported roughness geometries used for creating artificial roughness. Heat transfer coefficient and friction factor correlations developed by various investigators for roughened ducts of solar air heaters have also been reported in the present paper.     

Microstructural Evolution Under Low Shear Rates During Rheo Processing of LM25 Alloy

Microstructural features of LM25 alloy processed by two different routes: (1) conventional casting, and (2) shear casting based on inclined heated surface are studied. The microstructures of the primary phase for the shear-cast samples show rosette or ellipsoidal morphologies. Heat transfer of contacting melt with the inclined tube surface and shear stress exerted on the layers of the melt as result of gravitational force are crucial parameters for the microstructural evolution. Compared to those produced by conventional casting, shear-cast samples have a much improved tensile strength and ductility due to globular microstructure.