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691.
Tokuoka Y Suzuki M Ohsawa Y Ochiai A Ishizuka M Kawashima N 《Drug development and industrial pharmacy》2008,34(6):595-601
Enhancing effect of l-menthol and its derivatives, l-menthyl formate, l-menthyl acetate, and l-menthyl propionate, on skin permeation of 5-aminolevulinic acid (ALA) through Yucatan micropig full-thickness skin was investigated using a Franz-type diffusion cell. ALA solutions were prepared using ethanol-water mixed solvents with l-menthol or the derivative. Skin permeation coefficients (Kp) of ALA with more than 3.0 wt% of l-menthol was significantly larger than that without l-menthol. In addition, Kp of ALA with the derivative increased as follows: l-menthol approximately l-menthyl propionate < l-menthyl formate < l-menthyl acetate. These results suggest that l-menthol and the derivative are effective to enhance ALA skin permeation. 相似文献
692.
Sluka T Kodama H Fukada E Mokrý P 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(8):1859-1866
The design and realization of an adaptive sound-shielding system based on a method to control the effective elastic stiffness of piezoelectric materials are presented in this paper. In this system, the sound-shielding effect is achieved by a sound reflection from the piezoelectric curved membrane fixed in rigid frame and connected to an active analog circuit that behaves as a negative capacitor. The acoustic transmission loss through the curved membrane was measured for the incident sound of frequency 1.6 kHz and of acoustic pressure level 80 dB. When the negative capacitor in the system was properly adjusted, the acoustic pressure level of the transmitted sound was reduced from the initial 60 dB to 15 dB by the action of the negative capacitor. Then the system was exposed to naturally changing operational conditions, and their effect on sound-shielding efficiency was studied. It is shown that the acoustic transmission loss of the system dropped by 35 dB within 30 min from the moment of negative capacitor adjustment. Therefore, a self-adjustment of the system has been implemented by appending an additional digital control circuit to the negative capacitor. It is shown that the aforementioned deteriorating effect has been eliminated by the adjusting action of the control circuit. The long-time sustainable value of 60 dB in the acoustic transmission loss of the adaptive sound shielding system has been achieved. 相似文献
693.
694.
Omori Y Sakikubo T Nakane M Fuchu H Miake K Kodama Y Sugiyama M Nishikawa Y 《Journal of food protection》2010,73(10):1803-1808
To manufacture raw ham in an efficient manner, we recently developed a new system in which presliced pork loin was used, and the processing time was reduced to 5% of the conventional method. This study aimed to examine whether this raw ham could be as safe as ham produced by the conventional method. Pork loin spiked with enterohemorrhagic Escherichia coli serotype O157:H7, Listeria monocytogenes serotype 1/2c, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus were processed using either the new or conventional method. The fate of the foodborne pathogens and behavior of hygiene indicator bacteria were examined. Whereas nitrite had disappeared during the conventional packaging process, the reduced processing time in the new system allowed for the ham to be vacuum packed with retention of the nitrite (6.9±1.2 ppm, P<0.01). This accounts for the prominent decrease in L. monocytogenes (2.3 log reduction in 35 days) and S. aureus (3.3 log reduction in 13 days) counts during storage. E. coli O157 and Salmonella Enteritidis were likely resistant to the nitrite in the ham. However, they were unable to multiply in the ham and decreased gradually as in the conventionally produced ham. The bacteriostatic nature of the raw ham was also indicated by the gradual decrease in coliforms (1.3 log reduction in 13 days) in nonspiked ham. In conclusion, the raw ham produced using presliced pork loin is practically as safe as conventionally produced raw ham. It is worth validating these results in a small-scale production setting. 相似文献
695.
Hori H Nagaoka Y Yamamoto A Sano T Yamashita N Taniyasu S Kutsuna S Osaka I Arakawa R 《Environmental science & technology》2006,40(3):1049-1054
Decomposition of perfluorooctanesulfonate (PFOS) and related chemicals in subcritical water was investigated. Although PFOS demonstrated little reactivity in pure subcritical water, addition of zerovalent metals to the reaction system enhanced the PFOS decomposition to form F-ions, with an increasing order of activity of no metal approximately equal Al < Cu < Zn < Fe. Use of iron led to the most efficient PFOS decomposition: When iron powder was added to an aqueous solution of PFOS (93-372 microM) and the mixture was heated at 350 degrees C for 6 h, PFOS concentration in the reaction solution fell below 2.2 microM (detection limit of HPLC with conductometric detection), with formation of F-ions with yields [i.e., (moles of F- formed)/(moles of fluorine content in initial PFOS) x 100] of 46.2-51.4% and without any formation of perfluorocarboxylic acids. A small amount of CHF3 was detected in the gas phase with a yield [i.e., (moles of CHF3)/(moles of carbon content in initial PFOS) x 100] of 0.7%, after the reaction of PFOS (372 microM) with iron at 350 degree C for 6 h. Spectroscopic measurements indicated that PFOS in water markedly adsorbed on the iron surface even at room temperature, and the adsorbed fluorinated species on the iron surface decomposed with rising temperature, with prominent release of F- ions to the solution phase above 250 degrees C. This method was also effective in decomposing other perfluoroalkylsulfonates bearing shorter chain (C2-C6) perfluoroalkyl groups and was successfully applied to the decomposition of PFOS contained in an antireflective coating agent used in semiconductor manufacturing. 相似文献
696.
Degradation of C4F9C2H4OH in air over TiO2 particles was examined in this first report of gas-solid heterogeneous photochemical degradation of fluorotelomer alcohols (FTOHs), which may be precursors of perfluorocarboxylic acids (PFCAs) in the environment. Photoirradiation (>290 nm) of C4F9C2H4OH in air flowing over TiO2 produced CO2, via C4F9CH2CHO, C4F9CHO, CnF(2n+1)COF (n=2 and/or 3), and COF2, in that order. X-ray photoelectron spectroscopy of the Ti02 surface showed a decrease in the amount of fluorine bonded to carbon and an increase in the amount of F- as the degradation of C4F9C2H4OH in air proceeded. Of the carbon content in the initial C4F9C2H4OH (78.8 ppmv), 90.7% was transformed to CO2, and the predominant fluorine species produced on the TiO2 surface was F-. Fluorotelomer unsaturated acids, which are considered to be toxic and have been observed in the biodegradation of FTOHs, did notform. Increased relative humidity in the air accelerated the decomposition of the reaction intermediates, which led to increased CO2 and F- formation. This result indicates that humidity is a key factor for counteracting FTOHs in indoor air. Although perfluoroalkyl substances such as PFCAs in water reportedly undergo little photodegradation over TiO2, our data show that mineralization of C4F9C2H4OH in air can be achieved with TiO2. 相似文献
697.
Synthesis and Photocatalytic Activity of Titania Pillared Clays 总被引:13,自引:0,他引:13
T. Kaneko H. Shimotsuma M. Kajikawa MISSING END TAG Hatamachi T. Kodama Y. Kitayama 《Journal of Porous Materials》2001,8(4):295-301
TiO2-pillared clays such as montmorillonite, saponite and mica were prepared with an intercalation of polynuclear titanium complex formed by the reaction of Ti(i-C3H7O)4 and acetic acid. Characterization of the products was performed by XRD, XPS, IR, UV-V spectra, the measurement of surface area and pore size distribution. The photocatalytic decomposition of carboxylic acids has been studied on TiO2-pillared montmorillonite, saponite and mica. TiO2-pillared mica showed higher catalytic activity than TiO2 for the photocatalytic decomposition of acetic acid and adipic acid. On the contrarily, TiO2 was the most active catalyst and TiO2-pillared mica showed low activity for the photocatalytic decomposition of capric acid. The results show that the molecular size of carboxylic acid contributes to the catalytic activity of TiO2-pillared clays. 相似文献
698.
699.
Reactive thermal spray by high velocity ceramic jet and characterization of the coatings 总被引:13,自引:0,他引:13
A ceramic jet composed of molten particles in an electrothermally exploded powder spray was identified by the flash, soft
x-ray radiography technique. The velocity of the leading edge of the jet was estimated to be 900 m/s. The coating obtained
by a ceramic jet of titanium diboride consisted of a mixing layer of the substrate material and sprayed ceramics. A coating,
which exhibited no pores or cracks, was formed through the dense deposition and solidification of spray droplets. The successive
impacts of the droplets caused melting and stirring of the substrate surface to form a mixing layer. Some of these layers
were formed due to capillary movement of the molten substrate material into the fractures of coarse ceramic particles. Thermal
spray by chemical reaction between titanium and boron nitride particles resulted in a composite coating of TiN and TiB2. The character of the mixing layer indicated that the depth profiles depended on the substrate material. 相似文献
700.
Nonlinear interactions between neighboring pulses in optical-time-division-multiplexed (OTDM) systems may cause a timing jitter of the signal pulse, which results in a limitation of the transmission distance and bit-rate. We show that alternating the phases or amplitudes of pulses in the time sequence is effective for reducing the interactions between dispersion managed solitons as in the case of ideal solitons, but only for a relatively weak dispersion management 相似文献