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101.
Microwave driven wood liquefaction with glycols 总被引:1,自引:0,他引:1
Wood liquefaction with glycols using p-toluenesulfonic acid as the catalyst was carried out under microwave heating. With rapid heating and temperatures in the 190–210 °C range complete liquefaction was achieved in 7 min. Liquefaction efficiency was dependent on the choice of glycol. Simple glycols such as ethylene glycol and propylene glycol were more effective than higher analogues. The use of glycerol in mixtures with glycols showed a synergistic effect. Size exclusion chromatography was used to follow the gradual emergence of liquefaction products in solution as well as the recondensation products that start forming early in the reaction and precipitate from solution when molar masses of approx. 1 × 104 g/mol are reached. 相似文献
102.
《Electromagnetic biology and medicine》2013,32(2-3):161-169
A health survey was carried out in Murcia, Spain, in the vicinity of a Cellular Phone Base Station working in DCS‐1800 MHz. This survey contained health items related to “microwave sickness” or “RF syndrome.” The microwave power density was measured at the respondents' homes. Statistical analysis showed significant correlation between the declared severity of the symptoms and the measured power density. The separation of respondents into two different exposure groups also showed an increase of the declared severity in the group with the higher exposure. 相似文献
103.
摘要目的:评估超声造影(CEUS)引导下微波消融(MWA)治疗肝癌的有效性及应用价值。方法:108 例肝癌患者,共147个病灶经
MWA治疗。根据患者在做常规超声检查时,是否有扫查不清晰的结节或其他影像学检查提示可能存在多发结节等,分成CEUS
族和对照组。CEUS组41 名患者,年龄(57.9± 7.8)岁,共57 个病灶,平均直径(2.4± 1.5)cm,经超声造影引导下行微波消融治疗。
对照组67 名患者,年龄(55.5± 8.9)岁,共90 个病灶,平均直径(2.6± 1.7)cm,常规超声引导下同种条件行微波消融治疗。治疗后
对两组患者进行6~12 个月随访。结果:CEUS组的57 个病灶均清晰显示其位置、数目、大小、边界、形态,完全消融的结节为55
个,未完全消融的结节为2个。对照组67 名患者的90 个病灶,完全消融的病灶78 个;未完全消融的结节12 个。CEUS组完全消
融率高于病例对照组(96.49 %VS 86.67 %;P< 0.05)。随访6~12 个月后发现,CEUS 组完全消融率高于病例对照组(P< 0.05),差
异有统计学意义。结论:CEUS能更好的显示病灶的位置、数目、大小,更精确显示病灶边界、范围,造影引导下MWA 是一种有效
提高完全消融效率的方法,具有较大应用价值。 相似文献
104.
《Electromagnetic biology and medicine》2013,32(2):177-184
The purpose of this study was to investigate the effects of 9450-MHz microwaves and extremely low frequency magnetic fields (ELFMF) on the phagocytic activity of rat macrophages in control rats and those treated with vitamins C and E. In the microwave group, 24 albino Wistar rats were exposed to microwaves (2.65 mW/cm2, specific absorption rate [SAR]: 1.80 W/kg) for 1 h/day for 21 days. Thirty-two albino Wistar rats were divided into four groups (one control, three experimental) (n = 8). The rats in the first exposure group were only exposed to microwaves for 1 h per day for 21 days. In addition to exposure with microwaves as in the first experimental group, vitamins E and C (150 mg/kg/day) were injected intraperitoneally into the rats in the second and third exposure groups, respectively. In the magnetic field exposure group, 26 albino Wistar rats were divided into two groups: the sham (n = 12) and exposed groups (n = 14). The rats in the experimental group were exposed to ELFMF (50 Hz, 0.75 mT) for 3 h/day for 3 weeks. After completing the exposure period, the rats were sacrificed under ketalar anesthesia. The viability of isolated alveolar macrophages of rats in the microwave and ELF groups was determined and compared to sham groups. The results were analyzed with the Mann–Whitney U test. In the microwave group, the phagocytic activity in the experimental groups was found to be higher than the sham groups. However, with phagocytic activity in rats treated with both microwaves and vitamins, only the vitamin C group was significant (p < 0.05). In the magnetic field group, the phagocytic activity of rats exposed to ELFMF was lower than that of the sham group, but the results were not significant (p > 0.05). Rectal temperatures of microwaveexposed groups were found to be significantly higher compared to the control group (p < 0.05). 相似文献
105.
《Electromagnetic biology and medicine》2013,32(1):81-89
To determine whether or not mechanosensitive (MS) ion channels are present in the magnetotactic bacterium Magnetospirillum magnetotacticum, techniques for spheroplast preparation in Escherichia coli were adapted for this bacterium. This resulted in the formation of 2–3-μm spheroplasts, which were used for patch clamp analysis. Ion channel activity in M. magnetotacticum was compared with that of the MS of small conductance (MscS) in E. coli. This comparison reveals the presence of MscS-like channels in M. magnetotacticum and, as this bacterium produces intracellular magnetite (Fe3O4) particles similar to those found in the human brain, provides a model for investigation of the effects of magnetic fields on MS ion channels in magnetite-bearing cells. 相似文献
106.
Antigen retrieval (AR) is a technique that re-exposes epitopes in formalin fixed, paraffin embedded sections and makes them detectable by immunohistochemistry. We compared the effects of two AR procedures, enzyme digestion and microwave heating, on immunostaining of vimentin and desmin in formalin fixed, paraffin embedded tissues. Our results showed that AR is necessary for vimentin and desmin immunostaining in tissues fixed in formalin for more than 48 h. With prolonged fixation times, microwave heating showed better results than enzyme digestion for AR. The same results were obtained using 1% zinc sulfate or Citra Plus solution as retrieval solutions for microwave heating. We recommend microwave heating for AR, because it is easier to use and produces better results compared to enzyme treatment. 相似文献
107.
Barbara Rejasse Sylvain Lamare Marie-Dominique Legoy Thierry Besson 《Journal of enzyme inhibition and medicinal chemistry》2013,28(5):519-527
Although microwave-assisted reactions are widely applied in various domains of organic chemistry, their use in the area of enzyme chemistry has been rather limited, due to the high temperatures associated with the microwave heating: Because current technology, allows a good control of reaction parameters, several examples of microwave-assisted enzyme chemistry have been reported, using stable and effective biocatalysts (modified enzymes). The purpose of this review is to highlight the applications and studies on the influence of microwave irradiation on enzymatic properties and their application in enzyme chemistry. 相似文献
108.
109.
Nguyen To Hoai Akiyoshi Sasaki Masahide Sasaki Harumi Kaga Toyoji Kakuchi Toshifumi Satoh 《Carbohydrate research》2011,(13):1747
The dehydration of d-mannose and the demethanolization of methyl-α-d-mannopyranoside (MαMP) or methyl-α-d-mannofuranoside (MαMF) were examined using microwave-assisted heating for a 3-min irradiation at temperature from 120 to 280 °C in ordinary or dry sulfolane without any catalyst. The microwave-assisted heating of MαMP and MαMF smoothly proceeded to selectively afford the anhydromannoses, 1,6-anhydro-β-d-mannopyranose (AMP) and 1,6-anhydro-β-d-mannofuranose (AMF), respectively, in high yields. For MαMP in ordinary sulfolane at 240 °C, AMP was selectively obtained in the AMF:AMP ratio of 4:96, whereas AMF was the major product at the AMF:AMP ratio of 97:3 from MαMF in dry sulfolane at 220 °C. 相似文献
110.
Nishat R. Khan 《Biocatalysis and Biotransformation》2020,38(2):114-122
AbstractA cosmetic ester, cetyl oleate was synthesized using microwave irradiated system. The esterification reaction was carried using Candida antarctica lipase B in a solvent-free media. The influence of various reaction parameters was studied, and the efficiency of Fermase CALBTM10000 was compared with other enzymes. Equilibrium conversion of 97.5% was obtained within 20?min at 60?°C temperature, 1:2 oleic acid to cetyl alcohol molar ratio and 4% w/w dose of lipase. A comparative study showed that microwave irradiation is a much more efficient method than ultrasound irradiation and conventional heating. Fermase CALBTM10000 was reusable over 6 enzymatic cycles as its stability improved under microwave system. Physicochemical parameters of cetyl oleate were tested in order to analyze its suitability for further cosmetic use. 相似文献