Hydrogen adsorption on and diffusion through MoS2 monolayer: First-principles study

We investigate the hydrogen adsorption on and diffusion through the MoS₂ monolayer based on density-functional theory. We show that the hydrogen atom prefers to bond to the S atom at the monolayer, leading to enhanced conductivity. The hydrogen atom can also adsorb at the middle of the hexagon ring by overcoming an energy barrier of 0.57 eV at a strain of 8%. Also, we show that the MoS₂ monolayer is flexible and any mechanical deformation of the monolayer is reversible because the extension of the Mo–S bond is much smaller than the applied strain. The monolayer can block the diffusion of hydrogen molecule from one side to the other due to a high energy barrier (6.56 eV). However, the barrier can be reduced to 1.38 eV at a strain of 30% and even totally removed by creating S vacancies and applying a strain of 15%. The MoS₂ monolayer may find applications in sensors to detect hydrogen, and as mechanical valve to control the concentration of hydrogen gas.     

Characterising the release of flavour compounds from chewing gum through HS-SPME analysis and mathematical modelling

The headspace solid-phase microextraction (HS-SPME) technique combined with GC–MS was evaluated to study 33 selected flavour compounds released from chewing gum. The operating conditions of SPME were optimised, including different fibres (PDMS, DVB/CAR/PDMS, PA and PDMS/DVB), sample size, extraction time and temperature. The results indicated that while HS-SPME was a rapid and valuable technique, poor reproducibility occurred under all conditions. It was found that this deficiency could be alleviated by utilising mathematical modelling techniques, an approach which had not been previously used in the analysis of flavour compounds in chewing gum by HS-SPME. Compared to the instrumental analysis data themselves, the models provided more insights to the release behaviour of flavour compounds from chewing gum and the more reproducible kinetic rate constants might be used for comparing the release of different compounds or the same compound under different conditions.     

Partial purification and characterization of polyphenol oxidase from Chinese parsley (Coriandrum sativum)

Rates of thermal degradation and isomerization of all-trans-β-carotenes in air and in triacylglycerols were determined. Degradation of carotenes in triacylglycerols was faster than that in air. The 13-cis-β-carotene level in triacylglycerols was higher than in air. Oxidized materials of triacylglycerols probably facilitated isomerization of carotenes and, thus, degradation. Amounts of all-trans-β-carotenes and all-trans-α-carotenes in pumpkin decreased with an increase in heating time. The proportion of 13-cis-β-carotene increased after heat treatment started, probably due to thermal isomerization of all-trans-β-carotenes to cis-isomers, and to decreases in amounts of all-trans-β-carotenes and all-trans-α-carotenes in pumpkin. Effects of heating methods on proportions of isomers; however, were not different.     

The effect of resin finish on the dimensional stability of cotton knitted fabric

In this article, the effect of resin finish on the degree of set is discussed. Furthermore, the relationship of the degree of set and dimensional stability is analyzed. After relaxation treatments, the yarns in a fabric would be set at a certain level. As the fabric is subjected to prolonged relaxation treatments, the yarn will become more set until the shape of the unraveled yarn is similar to the shape of the loop in the fabric. The yarn that is removed from a knitted fabric has a curvature value close to zero, and the curvature is exactly as the corresponding position at the knitted loop. From previous research, it is known that the degree of set affects the dimensional properties in a plain knitted fabric. In this article, the degree of set increases with resin level. It explains why the resin finish can stabilize the dimensional properties indirectly.     

Influence of different extraction temperatures and methanol solvent percentages on the total phenols and total flavonoids from the heartwood and bark of Acacia auriculiformis

Acacia auriculiformis heartwood and bark were obtained, dried under shelter for 2 weeks and pulverized into powdered form to be extracted with the following extraction temperatures of 35, 55 and 75 °C and methanol solvent percentages of 55, 65 and 75 % for 3 h in a water bath. The material ratio used was 1:20 (pulverized samples: solvent). The total phenolics and flavonoids yield was determined by using a Thermo Scientific Genesys 10 UV–Visible Spectrophotometer. The optimum total phenolics and flavonoids yield were achieved by extraction with an extraction temperature of 75 °C and a methanol solvent percentage of 75 % for both the heartwood [75.44 % (total phenolics) and 36.64 % (total flavonoids)] and bark [87.18 % (total phenolics) and 99.10 % (total flavonoids)] of A. auriculiformis trees.     

Nanotech: propensity in foods and bioactives

Nanotechnology is seeing higher propensity in various industries, including food and bioactives. New nanomaterials are constantly being developed from both natural biodegradable polymers of plant and animal origins such as polysaccharides and derivatives, peptides and proteins, lipids and fats, and biocompatible synthetic biopolyester polymers such as polylactic acid (PLA), polyhydroxyalkonoates (PHA), and polycaprolactone (PCL). Applications in food industries include molecular synthesis of new functional food compounds, innovative food packaging, food safety, and security monitoring. The relevance of bioactives includes targeted delivery systems with improved bioavailability using nanostructure vehicles such as association colloids, lipid based nanoencapsulator, nanoemulsions, biopolymeric nanoparticles, nanolaminates, and nanofibers. The extensive use of nanotechnology has led to the need for parallel safety assessment and regulations to protect public health and adverse effects to the environment. This review covers the use of biopolymers in the production of nanomaterials and the propensity of nanotechnology in food and bioactives. The exposure routes of nanoparticles, safety challenges, and measures undertaken to ensure optimal benefits that outweigh detriments are also discussed.     

Stochastic grid bundling method for backward stochastic differential equations

ABSTRACT

In this work, we apply the Stochastic Grid Bundling Method (SGBM) to numerically solve backward stochastic differential equations (BSDEs). The SGBM algorithm is based on conditional expectations approximation by means of bundling of Monte Carlo sample paths and a local regress-later regression within each bundle. The basic algorithm for solving the backward stochastic differential equations will be introduced and an upper error bound is established for the local regression. A full error analysis is also conducted for the explicit version of our algorithm and numerical experiments are performed to demonstrate various properties of our algorithm.