The effects of lowering pH by an acidulant (citric acid) on the formation of acrylamide in fried and baked corn chips and in french fries were studied by using a GC/MS. The 0.2% citric acid treatments induced 82.2% and 72.8% inhibition of acrylamide formation in fried and baked corn chips, respectively. Dipping potato cuts in 1% and 2% citric acid solutions for 1 h before frying showed 73.1% and 79.7% inhibition of acrylamide formation in french fries. In the experiment of heating 1 mL solution containing asparagine and glucose in phosphate buffers, by lowering the pH from 7.0 to 4.0, 99.1% inhibition of acrylamide formation was achieved. This is the first finding of an effective, simple, and practical way to limit the acrylamide formation in real foods.

Localized surface plasmon (LSP) effects due to Ag and Ag/SiO2 nanoparticles (NPs) deposited on GaN/InGaN multiquantum well (MQW) light‐emitting diode (LED) structures are studied. The colloidal NPs are synthesized by a sol‐gel method and drop‐cased on the LED structures. The surface density of NPs its controlled by the concentration of the NP solution. Theoretical modeling is performed for the emission spectrum and the electric field distribution of LSP resonance for Ag/SiO2 NPs. Enhanced photoluminescence (PL) efficiency is observed in the LED structures and the amount of PL enhancement increases with increasing the surface density of Ag and Ag/SiO2 NPs. These effects are attributed to resonance coupling between the MQW and LSP in the NPs. It is also shown that the PL enhancement attainable with Ag NPs and Ag/SiO2 NPs is comparable, but the latter displays a much higher stability with respect to long‐term storage and annealing due to a barrier for NP agglomeration, Ag oxidation, and impurity diffusion provided by the SiO2 shell.

The effects of types and amount of catalysts, hydrogen pressure, and kinds of vegetable oils on the formation of CLA isomers were studied during hydrogenation. CLA isomers were identified by using a silver ion-impregnated high-performance liquid chromatograph and 100-m cyano-capillary column gas chromatograph. A selective catalyst (SP-7) produced a considerably higher content of CLA in soybean oil than nonselective catalysts. The maximal quantity of CLA produced in soybean oil during hydrogenation increased greatly with increasing amount of catalyst. By increasing the amount of selective catalyst from 0.05 to 0.3%, the quantity of total CLA obtained was about 1.9 times higher. Changes in hydrogen pressure also greatly influenced total CLA formed. By decreasing hydrogen pressure from 0.24 to 0.024 MPa, the quantity of CLA obtained was about 1.3 times higher. With different oil species (soybean, cottonseed, and corn oils), the time to reach the maximal quantity of CLA was different under the same hydrogenation conditions. However, the maximal quantity of CLA and proportion of CLA isomers formed were almost identical, regardless of oil species tested, under the same hydrogenation conditions. EXPERIMENTAL PROCEDURESMaterials. Authentic CLA methylesters, stearic acid methylester, oleic acid methylester, linoleic acid methyl ester, linolenic acid methylester, arachidic acid methylester, behenic acid methylester, and heptadecanoic acid methylester were purchased from Sigma Chemical Co. (St. Louis, MO). HPLCgrade hexane and acetonitrile were purchased from Mallinckrodt Specialty Chemicals (Paris, KY). Sodium methoxide in

A free-standing GaN layer was produced by combining electrochemical (EC) etching from the front surface, photo-electrochemical (PEC) etching from the back surface, and subsequent regrowth of GaN on the porous template thus produced. The EC etching resulted in the formation of etch channels on the surface portion of the starting film, whereas the back-side PEC etching gave rise to a columnar structure supporting the entire film. When the n-GaN layer was regrown on such template, the underlying columnar structure provided weak places for easy separation and transfer of the film by mechanical bonding.

The electrical properties, admittance spectra, microcathodoluminescence, and deep trap spectra of p-AlGaN films with an Al mole fraction up to 45% grown by both metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) were compared. The ionization energy of Mg increases from 0.15 to 0.17 eV in p-GaN to 0.3 eV in 45% Al p-AlGaN. In p-GaN films grown by MBE and MOCVD and in MOCVD grown p-AlGaN, we observed additional acceptors with a concentration an order lower than that of Mg acceptors, with a higher hole capture cross section and an ionization energy close to that of Mg. For some of the MBE grown p-AlGaN, we also detected the presence of additional acceptor centers, but in that case the centers were located near the p-AlGaN layer interface with the semi-insulating AlGaN buffer and showed activation energies considerably lower than those of Mg.