In vitro human digestion models for food applications

In vitro digestion models are widely used to study the structural changes, digestibility, and release of food components under simulated gastrointestinal conditions. However, the results of in vitro digestion models are often different to those found using in vivo models because of the difficulties in accurately simulating the highly complex physicochemical and physiological events occurring in animal and human digestive tracts. This paper provides an overview of current trends in the development and utilisation of in vitro digestion models for foods, as well as information that can be used to develop improved digestion models. Our survey of in vitro digestion models found that the most predominant food samples tested were plants, meats, fish, dairy, and emulsion-based foods. The most frequently used biological molecules included in the digestion models were digestive enzymes (pancreatin, pepsin, trypsin, chymotrypsin, peptidase, α-amylase, and lipase), bile salts, and mucin. In all the in vitro digestion models surveyed, the digestion temperature was 37 °C although varying types and concentrations of enzymes were utilised. With regard to digestion times, 2 h (the stomach, small intestine, and large intestine each) was predominantly employed. This survey enhances the understanding of in vitro digestion models and provides indications for the development of improved in vitro digestion models for foods or pharmaceuticals.     

Highly efficient uneven multi-level linc transmitter

To improve power efficiency in a transmitter, a novel method is proposed, this being an uneven multi-level linear amplifier with a nonlinear component (UMLINC). Compared to a normal multi-level LINC (MLINC), the UMLINC employs a new uneven multi-level signal component separator (UMSCS) that significantly improves transmitter efficiency.     

Mechanical properties of graphite/aluminum metal matrix composite joints by friction stir spot welding

Graphite/aluminum metal matrix composite (MMC) joints are successfully fabricated by friction stir spot welding (FSSW). During lap-joining processes of aluminum alloy sheets by FSSW, graphite/water colloid is applied between the tool shoulder and the upper plate. The Raman spectrum of the FSSW joint confirms that graphite/aluminum MMC is successfully induced in the stir zone. Quasi-static shear tests and micro hardness measurements of the FSSW joint also show that the strength and toughness of the joint are significantly improved by inducing graphite/aluminum MMC in the stir zone. The results of the present study suggest that the mechanical properties of structural components joined by spot welds can be easily enhanced by adopting MMC joints by FSSW, instead of changing the material or increasing the number of joints.     

Multi-antenna diversity gain in terrestrial broadcasting receivers on vehicles: A coverage probability perspective

This paper theoretically and empirically explores the reliability gain that can be obtained by installing multiple antennas in on-vehicle broadcasting receivers. Analytical derivations reveal that maximal-ratio-combining-based diversity allows a multi-antenna receiver (MR) to achieve significantly better coverage probability than a single-antenna receiver (SR). In particular, the notable MR gains for low-power reception and high-throughput services are highlighted. We also discuss various aspects of mobile MRs, including geometric coverage, volume of the users served, and impact of receiver velocity. To examine the feasibility of MRs in the real world, extensive field experiments were conducted, particularly with on-air ATSC 3.0 broadcast transmissions. Relying on the celebrated erroneous second ratio criterion, MRs with two and four antennas were verified to achieve notable reliability gains over SRs in practice. Furthermore, our results also prove that layered-division multiplexing can cope better with receiver mobility than traditional time-division multiplexing when multiple services are intended in the same radio frequency channel.     

Improved photocatalytic activity of surface charge functionalized ZnO nanoparticles using aniline

Functionalization of aniline molecules on zinc oxide(ZnO)nanoparticles is reported using a simple impregnation technique.Functionalized ZnO samples were systematically characterized based on mor-phology,surface and optical properties,and photocatalytic performance towards methyl orange(MO).Aniline functionalization increased the surface charge of the modified ZnO.Compared to pristine ZnO,the aniline-functionalized ZnO yielded faster photodegradation of MO,degrading 98.29％ of MO in 60 min and superoxide radicals were the major species during the MO photodegradation reaction.These results indi-cate that the improvement of photocatalytic degradation could be attributed to opposite charge-induced surface adsorption.Hence,protonated amine as a positively charged molecule was expected to increase the surface adsorption of MO(as an anionic dye)on ZnO nanoparticles surfaces,thereby increasing their photocatalvtic degradation performance.     

Study of the structural properties of goat's milk chocolates with different concentrations of cocoa mass

The objective of this study was to assess the microstructural characteristics of goat's milk chocolates formulated with different concentrations of cocoa mass by rheological measurements and microscopy. For rheological characterization, rotational and oscillatory tests were performed, while crystal morphology was observed by means of atomic force microscopy (AFM) and 3D optical profilometer. It was verified that the chocolates presented pseudoplastic and thixotropic behavior. The Herschel–Bulkley model adequately described the flow behavior of the formulations. In the oscillatory tests, it was found that the tangent δ (loss) decreased from 0.33 to 0.17 as a function of the increase in cocoa mass concentration. The creep recovery tests were consistent with the other rheological tests. The analysis of AFM and profilometer indicated that there are different microscopic pores on the surface of the chocolates, and that with the increase in the concentration of cocoa mass, it has a structure with greater interactions.     

Effect of photosensitivity in acrylic photoreactive electrode pastes on line width uniformity for large‐sized plasma display panels

Ag electrodes with line width uniformity for large‐sized plasma display panels were successfully fabricated through a photolithographic process using photosensitive Ag pastes with optimized photosensitive properties. The photosensitivity of the Ag electrode pastes in the photolithographic process was investigated as a function of the types and contents of photoinitiators, the molecular weights and acid values of acrylic binders with carboxylic acid groups, and the process variables, such as the UV‐light intensity and dose, with a step tablet. This study revealed that the photoinitiator was a major parameter for the photosensitivity of the Ag electrode pastes. With the photosensitivity of the photosensitive Ag electrode pastes optimized by the study of the photoinitiator contents, Ag electrodes with line width uniformity were achieved with an HSP‐188 photoinitiator content of 15 wt % on the basis of the reactive monomers, regardless of the variation of the light dose from 250 to 350 mJ/cm² and intensity from 15 to 25 mW/cm². © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of highly stable mesoporous aluminosilicates from commercially available zeolites and their application to the pyrolysis of woody biomass

Ordered mesoporous aluminosilicates have been successfully obtained via the simple combination of top–down and bottom–up approaches, using commercially available zeolites as the framework sources. The mesoporous aluminosilicates are characterized by XRD, N₂ sorption, SEM, TEM, ICP, and NMR, and have proven to have controllable aluminium contents, well-developed mesoporosity, and excellent hydrothermal stability. The hydrothermally stable mesoporous aluminosilicates, which possess the proper distribution of weak and strong acid sites, are applied as reusable heterogeneous catalysts for the pyrolysis of woody biomass. The mesoporous aluminosilicates in the present work showed good activity, selectivity, and even stability for the production of desirable organic compounds such as phenolics, in comparison to conventional HZSM-5 and Al-MCM-41.     

A Comparison of the Meat Qualities from the Hanwoo (Korean Native Cattle) and Holstein Steer

This study was conducted to compare the meat qualities from the Hanwoo (Korean native cattle) and Holstein steer. A total of 48 Hanwoo (Korean native cattle) and Holstein steers (20 months old and averaging 500 kg in weight) were allotted into one of four groups (T1, B1+ meat grade Hanwoo; T2, B1 meat grade Hanwoo; T3, B1+ meat grade Holstein; T4, B1 meat grade Holstein). Meat grade were estimated by the Korean carcass grading system (National Livestock Cooperatives Federation, NLCF, 1998). Water content was higher in both of B1+-grade Holstein and B1-grade Holstein sample. B1+-grade Holstein sample was also higher in crude protein content, whereas ash content was higher in both B1+- and B1-grade Hanwoo samples. Shear force value was significantly lower in Holstein samples compared with Hanwoo samples. In fatty composition, the ratio of unsaturated fatty acid was higher, and saturated fatty acid was lower in Holstein samples. In sensory evaluation, aroma was higher in B1-grade Hanwoo sample than those of other samples, whereas flavor was highest in B1+-grade Hanwoo sample. Tenderness was significantly higher in Holstein samples compared with Hanwoo samples. In conclusion, Hanwoo beef had higher ash contents, aroma, and flavor, whereas meat tenderness was higher in Holstein samples.     

Analysis of nitrifying bacterial communities in aerobic biofilm reactors with different DO conditions using molecular techniques

In order to assess the relationship between the dissolved oxygen (DO) concentration and the characteristics of nitrifying bacterial communities in an aerobic biofilm reactor, molecular techniques including denaturing gradient gel electrophoresis (DGGE)/cloning based on PCR targeting 16S rRNA and the amoA gene and fluorescence in situ hybridisation (FISH) were conducted. The D-1, D-2, D-3 and D-4 reactors with different DO concentrations (1, 3, 5 and 7 mg/L, respectively) were set up in the thermostat and acclimated. The optimal DO concentration with stable nitrification efficiency was above 5.0 mg/L. As was shown by the results of DGGE and cloning, the community of ammonia-oxidising bacteria (AOB) and the ratio of Nitrosomonas sp. changed only slightly despite their differing nitrification efficiencies. The results of FISH indicated that higher DO concentrations resulted in an increase in AOB and nitrite-oxidising bacteria (NOB), and a reduction in heterotrophic microorganisms. The INT-dehydrogenase activity (DHA) test demonstrated that the activity of AOB decreased with reductions in the DO concentration. This means that the DO concentration does not influence the community of AOB, but rather the activity of AOB. In the relationship between the attached biomass and the nitrification efficiency, only the active biomass affected the nitrification efficiencies.