Effect of processing method on vitamin profile,antioxidant properties and total phenolic content of coconut (Cocos nucifera L.) sugar syrup

Coconut (Cocos nucifera L.) sugar is a more nutritious alternative sugar source as compared to sugar palm (Borassus flabellifer) and sugarcane (Saccharum officinarum L.). This work was aimed to investigate the browning index (BI), vitamin profile and antioxidant properties of coconut sap sugar syrups, which were produced by different processing methods: rotary evaporation (RE), microwave evaporation (ME) and open-heat evaporation (OHE). The results obtained showed that coconut sugar syrup produced by RE-60 contained high antioxidant activities [DPPH (36.71%) and ABTS (34.84%), TPC (299.87 mg per 100 g sample) and FRAP (3.74 mm )]. These values were slightly lower than those of ME and OHE. Coconut sugar syrup (RE-60) also contained higher amounts of vitamin C (1587.27 mg L⁻¹), vitamin B1 (97.44 mg L⁻¹) and vitamin B3 (19.84 mg L⁻¹) compared with those of ME and OHE coconut sugar syrups. RE-60 was the best method to produce coconut sugar syrup in a shorter time with lower browning index and higher vitamin contents.     

Hepatitis B Virus-Like Particle: Targeted Delivery of Plasmid Expressing Short Hairpin RNA for Silencing the Bcl-2 Gene in Cervical Cancer Cells

Gene therapy research has advanced to clinical trials, but it is hampered by unstable nucleic acids packaged inside carriers and there is a lack of specificity towards targeted sites in the body. This study aims to address gene therapy limitations by encapsidating a plasmid synthesizing a short hairpin RNA (shRNA) that targets the anti-apoptotic Bcl-2 gene using truncated hepatitis B core antigen (tHBcAg) virus-like particle (VLP). A shRNA sequence targeting anti-apoptotic Bcl-2 was synthesized and cloned into the pSilencer 2.0-U6 vector. The recombinant plasmid, namely PshRNA, was encapsidated inside tHBcAg VLP and conjugated with folic acid (FA) to produce FA-tHBcAg-PshRNA VLP. Electron microscopy revealed that the FA-tHBcAg-PshRNA VLP has an icosahedral structure that is similar to the unmodified tHBcAg VLP. Delivery of FA-tHBcAg-PshRNA VLP into HeLa cells overexpressing the folate receptor significantly downregulated the expression of anti-apoptotic Bcl-2 at 48 and 72 h post-transfection. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay demonstrated that the cells’ viability was significantly reduced from 89.46% at 24 h to 64.52% and 60.63%, respectively, at 48 and 72 h post-transfection. As a conclusion, tHBcAg VLP can be used as a carrier for a receptor-mediated targeted delivery of a therapeutic plasmid encoding shRNA for gene silencing in cancer cells.     

Thermal Evaluation of Diesel/Hydrogen Peroxide Fuel Blend

Thermal properties of fossil fuel are the key fundamental characteristics, which can distinguish any compound as a potential fuel. The performance of diesel fuel blend along with stability and solubility parameter designs are evaluated. The results from the experimental study indicate that the increase in hydrogen peroxide (H₂O₂) amount enhances the cetane number of diesel fuel blend significantly. However, the calorific value decreases as compared to pure diesel fuel. All values performed well according to the ASTM D‐975 diesel testing method. The thermodynamics of the prepared fuel blends also revealed that substantial solubility and diesel/H₂O₂ blend stability are provided even at lower temperatures. Such blends can be used as a feasible replacement of pure diesel fuel.     

Organic–inorganic nanomatrix structure and properties of related naturally occurring rubbery macromolecules

The outstanding mechanical properties of soft materials i.e. natural rubber are partly due to the organic–inorganic nanomatrix structure because numerous organic microparticles are dispersed in a small amount of an inorganic nanomatrix composed of inorganic nanoparticles and organic macromolecules. Here we form an organic–inorganic nanomatrix using graft-copolymerization of a vinyl monomer with an inorganic oxide precursor onto natural rubber particles with an average diameter of 1 μm dispersed in water. The inorganic oxide precursor is converted into inorganic oxide nanoparticles through hydrolysis and condensation, forming chemical linkages between natural rubber microparticles and inorganic oxide nanoparticles. Transmission electron microscopy indicates that the organic–inorganic nanomatrix is densely filled with inorganic oxide nanoparticles and the natural rubber microparticles are dispersed in the nanomatrix. This nanomatrix composite realizes both energetic elasticity and entropic elasticity of a soft material, opening a novel field of building block chemistry with respect to a pair of organic microparticles and inorganic nanoparticles.     

Study of morphology and gas separation properties of polysulfone/titanium dioxide mixed matrix membranes

Polysulfone (PSf)‐based mixed matrix membranes (MMMs) with the incorporation of titanium dioxide (TiO₂) nanoparticles were prepared. Distribution and agglomeration of TiO₂ in polymer matrix and also surface of membranes were observed by scanning electron microscopy, transmission electron microscopy, and energy dispersive X‐ray. Variation in surface roughness of MMMs with different TiO₂ loadings was analyzed by atomic force microscopy. Physical properties of membranes before and after cross‐linking were identified through thermal gravimetric analysis. At low TiO₂ loadings (≤3 wt%), both CO₂ and CH₄ permeabilities decreased and consequently gas selectivity improved and reached to 36.5 at 3 bar pressure. Interestingly, PSf/TiO₂ 3 wt% membrane did not allow to CH₄ molecules to pass through the membrane and this sample just had CO₂ permeability at 1 bar pressure. Gas permeability increased considerably at high filler contents (≥5 wt%) and CO₂ permeance reached to 37.7 GPU for PSf/TiO₂ 7 wt% at 7 bar pressure. It was detected that, critical nanoparticle aggregation has occurred at higher filler loadings (≥5 wt%), which contributed to formation of macrovoids and defects in MMMs. Accordingly, MMMs with higher gas permeance and lower gas selectivity were prepared in higher TiO₂ contents (≥5 wt%). POLYM. ENG. SCI., 55:367–374, 2015. © 2014 Society of Plastics Engineers     

Recovery error bounds on compressed sensing of noisy signals

Compressed sensing is an emerging technique in the field of digital signal acquisition. It promises almost exact recovery of high‐dimensional signals from a very small set of measurements. However, this technique is challenged by the task of recovering signals immersed in noise. In this paper, we derive upper and lower bounds on mean squared recovery error of noisy signals. These bounds are valid for any number of acquired measurements and at any signal‐to‐noise ratio. This work is highly useful for the design of any compressed sensing‐based real world application by quantifying recovery error entailed with realistic digital signal acquisition scenarios. Copyright © 2013 John Wiley & Sons, Ltd.     

Investigation of functionally graded metal foam thermal management system for solar cell

Concentrated photovoltaic cell (CPV) is a solar energy harvesting device that converts solar energy into electrical energy. However, the performance and efficiency of the CPV are heavily dependent on the temperature. Besides, nonuniformity of temperature distribution on the CPV will lead to thermal aging and affects the cycle life. Hence, an effective cooling system is required to remove excess heat generated to ensure that the CPV operates at optimum operating temperature with minimum variation of temperature. Metal foam is a new class of material that possesses huge potential for thermal management. In this study, a functionally graded metal foam is proposed for the CPV thermal management system. Computational thermal fluid dynamic analysis is conducted to investigate the effect of porosity and pore density on the flow field and thermal performance of the aluminum foam heat sink. The investigation results revealed that 10 PPI functionally graded aluminum foam heat sink with two stages of porosity gradient 0.794 and 0.682 produced the lowest pressure drop and highest thermal performance. Temperature difference of 3.9°C was achieved for a solar cell with total heat generation of 900 W under water mass flow rate of 20 gs⁻¹.