Comparative Study of Tocopherol Contents and Fatty Acids Composition in Twenty Almond Cultivars of Afghanistan

Afghanistan is the fourth largest producer of almonds in the world producing 78 native and 6 imported cultivars. However, till date, there have been no comprehensive data on nutrient profiles of the native cultivars. Thus, in the present investigation, tocopherol contents and fatty acid composition from the kernels of 20 selected native almond cultivars of Afghanistan were analyzed. The ranges of variability for the studied nutrients were similar to those already reported for almonds grown in other countries, such as 47.8–66.1% of total lipids (fresh weight basis), 62.54–81.57% of oleic acid in the total lipids, and 139.1–355.0 μg/g α-tocopherol in kernels. With respect to cultivars, significantly (p < 0.05) high content of total lipids were recorded in ‘Belabai’ and ‘Sattarbai’ (Afghan grade), oleic acid in ‘Khairodini’ and of α-tocopherol in ‘Khairodini-161 Samangan’ and ‘Belabai’ cultivars. Kernels from these cultivars can be used for nutrient dense food formulations. Daily consumption of 50 g almonds is sufficient to meet the RDA of α-tocopherol (15 mg/day), considering the average 300 μg/g of α-tocopherol in Afghan almonds. Also, these nutrient rich cultivars can be used in almond breeding programs globally, to focus on improving kernel oil composition and nutrient contents.     

Water absorption,residual mechanical and thermal properties of hydrothermally conditioned nano-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> enhanced glass fiber reinforced polymer composites

The durability of the nano-Al₂O₃ enhanced glass fiber reinforced polymer (GFRP) composites in hydrothermal environment is necessary for hydro/hygro thermal applications. The present investigation emphasizes the effect of nano-Al₂O₃ filler concentration on moisture absorption kinetics, residual mechanical and thermal properties of hydrothermally treated GFRP nano-composites. Nano-Al₂O₃ particles were mixed with epoxy matrix through temperature assisted magnetic stirrer and followed by ultrasonic treatment. It has been observed that, the addition of 0.1 wt% of nano-Al₂O₃ into the GFRP nano-composites reduces the moisture diffusion coefficient by 10%, as well as improves the flexural residual strength by 16% and interlaminar residual shear strength by 17% as compared to the neat epoxy GFRP composites. However, the glass transition temperature has not been improved by the addition of nano-Al₂O₃ filler. Weibull design parameters have been determined for dry and hydrothermally conditioned nano-composites. A good agreement between the experimental and the simulated stress–strain results has been observed. The interface failure mechanism has been evaluated by field emission scanning electron microscope to support the new findings.     

Spray Drying of Elderberry (Sambucus nigra L.) Juice to Maintain Its Phenolic Content

Spray drying was studied with Elderberry (Sambucus nigra L.) juice using a Buchi B-290 spray dryer. Different inlet temperatures ranging from 70°C to 120°C and two feed flow rates of 180 ml/hr and 300 ml/hr were considered for the experiment. The operating parameters were optimized in terms of total phenolic content retention, color, and powder recovery. The inlet temperature of 80°C with feed flow rate of 180 ml/hr gave high phenolic content retention with good color but lower recovery of the dried powder, i.e., less than 50%. To increase the recovery percentage during the drying process, the elderberry juice was spray dried with five different wall materials, i.e., soya milk powder, soya protein powder, isolated soya protein, gum acacia, and maltodextrin. Wall materials were evaluated in terms of total phenolic content retention, color of the powder, and mass recovery percentage. The gum acacia and maltodextrin gave better results and high recovery percentage, i.e., more than 70%. The best three combinations were stored under three different storage conditions in three different packagings to monitor the stability of the phenolic content and color of the powder.     

Ionic conductivity,dielectric behavior,and HATR–FTIR analysis onto poly(methyl methacrylate)–poly(vinyl chloride) binary solid polymer blend electrolytes

Solid polymer electrolytes comprising blends of poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) as host polymers and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) as dopant salt were prepared by solution‐casting technique. The ionic conductivity and dielectric behavior were investigated by using AC‐impedance spectroscopy in the temperature range of 298–353 K. The highest ionic conductivity of (1.11 ± 0.09)×10^?6 S cm^?1 is obtained at room temperature. The temperature dependence of ionic conductivity plots showed that these polymer blend electrolytes obey Arrhenius behavior. Conductivity–frequency dependence, dielectric relaxation, and dielectric moduli formalism were also further discussed. Apart from that, the structural characteristic of the polymer blend electrolytes was characterized by means of horizontal attenuated total reflectance–Fourier transform infrared (HATR–FTIR) spectroscopy. HATR–FTIR spectra divulged the interaction between PMMA, PVC, and LiTFSI. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Composite polymeric microsponge-based long-acting gel formulation for topical delivery of mupirocin

Topical delivery of medicaments in a controlled manner is still a promising area of research. Drug-containing dammar gum-ethyl cellulose composite microsponge loaded gel formulation (D-MSPG) was developed for controlled topical delivery of mupirocin. The drug-loaded microsponges (D-MSPs) were formulated by the quasi-emulsion solvent diffusion method and were evaluated for morphology, particle size distribution, entrapment efficiency, thermal properties, and crystallinity. The optimized D-MSPs (entrapment efficiency 91.5 ± 4.0% and particle size of 55.15 ± 2.9 μm) were dispersed in carbopol 934 gel (D-MSPG). The final product was characterized for pH, viscosity, texture, spreadability, consistency, syneresis, in vitro drug release, and ex vivo skin penetration study. A comparative study with marketed formulation was performed. For optimized gel formulation (G4), drug content was 104.19 ± 1.68%, and drug release was 84.19% after 24 h. The pH of the optimized gel was observed to be 6.05 ± 0.04. Viscosity of the optimized gel formulation was found to be 1212.15 ± 434.85 mPa-s at 50 s⁻¹. The steady-state flux (J) in ex vivo skin permeation was observed to be 53.96 μg cm⁻² h⁻¹ and the permeability coefficient was 2.69 cm/h for the optimized gel formulation. According to the findings, the D-MSPG-based formulation strategy can act well to prolong the topical delivery of mupirocin or similar drug molecules.     

Magnetron sputter deposition of hafnium nitride coating on high density graphite and niobium substrates

Hafnium nitride (HfN) is a refractory compound considered to be a suitable material for reaction barriers. The present paper deals with the preparation of HfN thin films by reactive magnetron sputtering on high density (HD) graphite and niobium substrates. Deposition process parameters have been optimised with Si(100) substrate in order to get HfN coating of 3 μm thickness. The optimised parameters were used to deposit HfN on HD graphite and on niobium substrates. The results showed that HfN coating with a thickness of 2.8 μm was successfully deposited on HD graphite and niobium substrates. The presence of HfN was confirmed by glancing incidence X-ray diffraction (GIXRD) and X-ray photoelectron spectroscopy (XPS). XRD studies on HfN coating on Si(100), HD graphite and Nb substrates showed nanocrystalline grains of size 130, 55 and 46 Å, respectively. The surface morphology of HfN coating on HD graphite and niobium by atomic force microscope (AFM) and scanning electron microscope (SEM) showed that nanoparticles are getting agglomerated into clusters. The HfN coating on niobium substrate exhibited good adhesion compared to that on HD graphite as studied by microscratch test. The thermal stress generated in the sputter deposited HfN coating on HD graphite and niobium substrates were calculated by analytical formula for thermal stress. The tensile and highly compressive stresses observed in the HfN coating on niobium and HD graphite, respectively, indicated a lower adhesive strength of the coating on the later than that of the former.     

Sintering and mechanical properties of MgO-doped nanocrystalline hydroxyapatite

Hydroxyapatite (HA) has been extensively studied for its exceptional ability in promoting osseointegration as in bone graft substitute and biomimetic coating of prosthetic implants. However poor mechanical properties of HA, in particular its low fracture toughness, has made its widespread adaption in a number of biomedical applications challenging. Here we employ an optimized wet precipitation method to synthesize nanocrystalline HA with significantly improved mechanical properties. In addition doping by MgO is found to effectively suppress grain growth and enhance fracture toughness by nearly 50% while good densification and phase stability in all samples regardless of concentration of dopant are fully maintained. Microstructural analysis further suggests that the exceptionally superior mechanical properties can be explained by migration of MgO to grain boundaries where they transform the more common transgranular fracture into an intergranular mode. Our biodegradation tests also confirm that MgO-doped HA is indeed a suitable candidate for load bearing implants.     

Pressure induced order-disorder transition in a diblock copolymer

Polymers are known to undergo order↔order and order↔disorder transitions, when subjected to a change of pressure, temperature, solvent, pH of the medium etc. The molecular processes, which alter the volume of the system, are found to be highly sensitive to the pressure. In the present communication Zimm and Bragg model of helix↔coil transition has been modified to interpret the experimental data of pressure induced phase transition in polystyrene-polybutadiene [PS-PB] at different pressurization rates, as reported by Migler and Han, utilizing the Birefringence and small angle neutron scattering technique. An expression for the degree of order is obtained from the grand partition function for the entire chain in terms of nucleation parameter, which controls the transition width. The nucleation parameter σ increases with the increase in the ODT temperatures of the system. The phenomenon of hysteresis has been discussed in relation to the pressurization rate, which increases/decreases with the corresponding increase/decrease in the pressurization rate. The theoretical transition curves are found to be in good agreement with experimental data.     

Electrical and Dielectric Properties of Non-magnetic Al<Superscript>3+</Superscript> Substituted Ni–Zn Nano Ferrites for High Frequency Applications

The effect of Al substitution on electrical and dielectric parameters of Ni–Zn ferrite has been discussed in the present work. The phase identification, surface morphology was studied using X-ray diffractometer (XRD), scanning electron microscope (SEM), respectively. The XRD patterns confirm the single-phase formation of these ferrites. With Al³⁺, substitution lattice parameter decreases due to smaller Al³⁺ ions replacing Fe³⁺ ions. The average grain size obtained from SEM results are in the range of 390–27 nm. The DC resistivity was observed to increase with increasing Al³⁺ ions concentration due to the unavailability of Fe³⁺ ions. Dielectric constant (\(\upvarepsilon ^{\prime }\)) and dielectric loss tangent (tan δ) have been studied as a function of frequency (1 kHz–10 MHz) and temperature (50–300 °C). The observed results are explained on the basis of interfacial polarization as predicted by Maxwell and Wagner.     

Selectivity engineering in the O‐ versus C‐alkylation of p‐cresol with cyclohexene over sulfated zirconia

Solid acids are more widely used as heterogeneous catalysts, because they are eco‐friendly. This paper reports the results for the Friedel‐Crafts alkylation of p‐cresol with cyclohexene using solid acids sulfated zirconia, 20% w/w dodecatungstophosphoric acid (DTP) supported on K10 clay and ZnCl₂/K10 (Clayzic). This reaction gave substantial amount of 1‐cyclohexyloxy‐4‐methyl benzene (O‐alkylated product) and 4‐cyclo‐hexyl‐4‐methyl phenol (C‐alkylated product). Both products are of commercial importance as perfume and insecticide respectively. Sulfated zirconia catalyst was shown to be better than others studied in terms of activity and selectivity to the O‐alkylated product. The kinetics were studied with sulfated zirconia as catalyst where the rate determining step was the surface reaction between chemisorbed cyclohexene and p‐cresol from the liquid phase within pores according to the Eley‐Rideal mechanism. The production of O‐alkylated p‐cresol is favoured at lower temperatures and C‐alkylated product at higher temperatures. The best operating temperature is 353 K. The activation energies for O‐ and C‐alkylation are 72.68 and 118.28 kj/mol, respectively.