Preparation and identification of angiotensin I-converting enzyme inhibitory peptides from sweet potato protein by enzymatic hydrolysis under high hydrostatic pressure

Sweet potato protein hydrolysates (SPPH) with angiotensin I-converting enzyme (ACE) inhibitory activity were prepared by papain, pepsin and alcalase under high hydrostatic pressure (HHP, 100–300 MPa). HHP significantly increased degree of hydrolysis (DH), nitrogen recovery (NR) and molecular weight (MW) <3 kDa fractions contents of SPPH by all three enzymes (P < 0.05). MW < 3 kDa peptide fractions from SPPH by alcalase under 100 MPa showed the highest ACE inhibitory activity (IC₅₀ value 32.24 µg mL⁻¹), and was subjected to purification and identification by semi-preparative RP-HPLC and LC-MS/MS. Fifty-four peptides ranged from 501.28 to 1958.88 Da with 5–18 amino acids were identified and matched sporamin A and B sequences. Five identified peptides with sequences of VSAIW, AIWGA, FVIKP, VVMPSTF and FHDPMLR displayed good ACE inhibitory activity with the contribution of Val, Trp, Phe and Arg. Thus, SPPH by enzymatic hydrolysis under HHP can be potentially used in functional food.     

Analysis of microstructure replication using vibratory assisted thermal imprint process

Microsystem Technologies - In this article, thermal imprint process for replication of high-quality microstructures on the surface of polymer is investigated. Vibrations has been previously...     

Development of sustainable engineered stone cladding for toughness,durability, and energy conservation

This study aims to investigate the techniques of manufacturing an improved engineered stone for better toughness, ductility, durability, and thermal resistance. The new artificial stone consists of two layers. The face layer is made strong, durable, colored, and smooth/or textured for natural look, while the back layer is light, high impact resistance, and low heat conductivity for better insulation and energy cost. The back layer utilizes recycled crumb rubber, which provides a combined solution for energy saving and environmental concerns. It reduces the material unit weight, enhances ductility and toughness, and improves thermal resistance. The stone’s properties such as compressive strength, thermal conductivity, durability, impact resistance and water absorption were experimentally measured and compared with natural stone specimens.     

Green's function expansion for exponentially graded elasticity

New computational forms are derived for Green's function of an exponentially graded elastic material in three dimensions. By suitably expanding a term in the defining inverse Fourier integral, the displacement tensor can be written as a relatively simple analytic term, plus a single double integral that must be evaluated numerically. The integration is over a fixed finite domain, the integrand involves only elementary functions, and only low‐order Gauss quadrature is required for an accurate answer. Moreover, it is expected that this approach will allow a far simpler procedure for obtaining the first and second‐order derivatives needed in a boundary integral analysis. The new Green's function expressions have been tested by comparing with results from an earlier algorithm. Copyright © 2009 John Wiley & Sons, Ltd.     

The hydrometallurgical extraction of lithium from egyptian montmorillonite-type clay

The processing of El-Fayoum montmorillonite-type clay deposits is attained through leaching with commercial sulfuric acid using a ball-mill-type autoclave. This process yields lithium sulfate, which can be used either for the production of lithium carbonate or to produce lithium metal. The effects of temperature, grain size, and sulfuric acid concentration and leaching on lithium recovery as well as the kinetics of the leaching process have been studied.     

FPGA-Based Network Traffic Security： Design and Implementation Using C5.0 Decision Tree Classifier

In this work, a hardware intrusion detection system （IDS） model and its implementation are introduced to perform online real-time traffic monitoring and analysis. The introduced system gathers some advantages of many IDSs： hardware based from implementation point of view, network based from system type point of view, and anomaly detection from detection approach point of view. In addition, it can detect most of network attacks, such as denial of services （DOS）, leakage, etc. from detection behavior point of view and can detect both internal and external intruders from intruder type point of view. Gathering these features in one IDS system gives lots of strengths and advantages of the work. The system is implemented by using field programmable gate array （FPGA）, giving a more advantages to the system. A C5.0 decision tree classifier is used as inference engine to the system and gives a high detection ratio of 99.93%.     

Evidence for structural phase transitions and large effective band gaps in quasi-metallic ultra-clean suspended carbon nanotubes

We report evidence for a structural phase transition in individual suspended metallic carbon nanotubes by examining their Raman spectra and electron trans- port under electrostatic gate potentials. The current-gate voltage characteristics reveal anomalously large quasi-metallic band gaps as high as 240 meV, the largest reported to date. For nanotubes with band gaps larger than 200 meV, we observe a pronounced M-shape profile in the gate dependence of the 2D band （or G＇ band） Raman frequency. The pronounced dip （or softening） of the phonon mode near zero gate voltage can be attributed to a structural phase transition （SPT） that occurs at the charge neutrality point （CNP）. The 2D band Raman intensity also changes abruptly near the CNP, providing further evidence for a change in the lattice symmetry and a possible SPT. Pronounced non-adiabatic effects are observed in the gate dependence of the G band Raman mode, however, this behavior deviates from non-adiabatic theory near the CNP. For nanotubes with band gaps larger than 200 meV, non-adiabatic effects should be largely suppressed, which is not observed experimentally. This data suggests that these large effective band gaps are primarily caused by a SPT to an insulating state, which causes the large modulation observed in the conductance around the CNP. Possible mechanisms for this SPT are discussed, including electron-electron （e.g., Mott） and electron-phonon （e.g., Peierls） driven transitions.     

New azodisperse dyes with thiazole, thiophene, pyridone and pyrazolone moiety for dyeing polyester fabrics

New antipyrinylazo dyes were prepared by diazocoupling of 4-antipyrinyl diazonium chloride with a variety of coupling components e.g. thiazole, thiophene, pyridone, and pyrazole moieties. The synthesized dyes were characterized by UV-visible absorption, IR, ¹H NMR, and MS spectroscopy. These dyes were applied as disperse dyes for dyeing polyester fabrics and their fastness properties were evaluated. Also the position of color in CIELAB coordinates (L*, a*, b*, H*, C*) was assessed.     

Preliminary Investigation of Copper Joints Soldered with Sn58Bi

In recent years, intensive studies have been carried out to find an alternative for Tin (Sn)-Lead (Pb) solder alloys with increasing demand over lower temperature solder alloys in current electronic packaging industry. High temperature operational solder alloys seem to produce drawback to other components on the printed circuit board (PCB). Low melting temperature Sn58Bi substrate as a potential replacement was investigated in this paper based on the melting properties, wettability, and shear strength. The Sn58Bi was soldered at a temperature below 200 ℃ on the Cu substrate, and the shear strength and contact angle were calculated. A peak temperature (melting temperature, TM) of 144.83 ℃ was identified. Single lap joint method was performed at a strain rate of 0.1 mm/min and an average shear strength of 23.4 MPa was found from three samples. The contact angle (wettability) was calculated to study the solder joint behaviour at reflow temperature of 170 ℃. The contact angle of the Sn58Bi was found to be 32.4 ° and considered to be desired value since the angle is less than 50 °. The low temperature soldering provides a preliminary result to allow further application on the real PCB.