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161.
162.
Liana Alvares Rodrigues Tiago Moreira Bastos Campos Manoel Orlando Alvarez-Mendes Aparecido dos reis Coutinho Kumiko Koibuchi Sakane Gilmar Patrocínio Thim 《Journal of Sol-Gel Science and Technology》2012,63(2):202-210
Carbon xerogel (CX) was used for phenol adsorption from aqueous solution. CX was synthesized by sol?Cgel polycondensation of resorcinol with formaldehyde using sodium carbonate (Na2CO3) as catalyst. Then, it was dried by convective drying technique and pyrolyzed under inert atmosphere. Phenol adsorption kinetics was very fast, what was attributed to the presence of open pore structure. The kinetic studies showed that the adsorption process could be fitted to a pseudo-second-order model and the particle diffusion process is the rate-limiting step of the adsorption. The phenol removal was maximum and unaffected by pH changes when the initial pH of the phenol solution was in the range of 3?C8. The optimum adsorbent dose obtained for phenol adsorption onto CX was 0.075?g/50?cm3 solution. The Langmuir model described the adsorption process better than the Freundlich isotherm model and the monolayer adsorption capacity is 32?mg?g?1. Among the desorbing solutions used in this study, the most efficient desorbent was EtOH (100?%) which released about 87?% of phenol bound with the CX. 相似文献
163.
Liana Iachetta Lada Malek Brian M. Ross 《Rapid communications in mass spectrometry : RCM》2010,24(6):815-822
The reactions of H3O+, NO+, and O with nineteen ester compounds occurring naturally in plants, and having important flavourant properties, were examined using selected ion flow tube mass spectrometry (SIFT‐MS). The H3O+ reactions primarily generate [R1COOR2·H]+, and may also produce [R2]+ fragment ions and/or fragmentation within the ester linkage. Collisional association/adduct ions, [R1COOR2·NO]+, are the main products formed in the NO+ reactions, although the carboxyl fragment ion is also detected frequently. The identification of the parent compound may be made more easily in the H3O+ and NO+ reactions. The inclusion of O reactions in the analysis provides additional information, which may be applied when the identity of a parent compound cannot be determined solely from the H3O+ and NO+ analysis. Consideration of the product ions generated with the three precursors suggests that SIFT‐MS can differentiate between many of the esters investigated, including isomers, although the product ions generated in the reactions with some esters are too similar to allow independent quantification. Our data therefore suggest that SIFT‐MS may be a useful tool to rapidly analyse and quantify flavourant esters in complex gas mixtures. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
164.
Adsorption kinetic,thermodynamic and desorption studies of phosphate onto hydrous niobium oxide prepared by reverse microemulsion method 总被引:1,自引:0,他引:1
A type of Nb2O5⋅3H2O was synthesized and its phosphate removal potential was investigated in this study. The kinetic study, adsorption isotherm,
pH effect, thermodynamic study and desorption were examined in batch experiments. The kinetic process was described by a pseudo-second-order
rate model very well. The phosphate adsorption tended to increase with a decrease of pH. The adsorption data fitted well to
the Langmuir model with which the maximum P adsorption capacity was estimated to be 18.36 mg-P g−1. The peak appearing at 1050 cm−1 in IR spectra after adsorption was attributed to the bending vibration of adsorbed phosphate. The positive values of both
ΔH° and ΔS° suggest an endothermic reaction and increase in randomness at the solid-liquid interface during the adsorption. ΔG° values obtained were negative indicating a spontaneous adsorption process. A phosphate desorbability of approximately 68%
was observed with water at pH 12, which indicated a relatively strong bonding between the adsorbed phosphate and the sorptive
sites on the surface of the adsorbent. The immobilization of phosphate probably occurs by the mechanisms of ion exchange and
physicochemical attraction. Due to its high adsorption capacity, this type of hydrous niobium oxide has the potential for
application to control phosphorus pollution. 相似文献
165.
Ferreira MC Brito VN Gameiro J Costa MR Vasconcellos EC Cruz-Hofling MA Verinaud L 《Journal of photochemistry and photobiology. B, Biology》2006,84(2):141-149
Paracoccidioidomycosis (PCM) is the most prevalent human mycosis in Latin America. The infection is thought to take place firstly in the lungs and then may disseminate to other organs and tissues. Treatment by currently available antifungals is lengthy, the drugs may have undesirable side effects, and some are costly. Occasional resistant strains of Paracoccidioides brasiliensis, the causative agent of PCM, have been reported. So, the search for more efficient treatments or adjuvant therapies has to be continued. In this work, we evaluated the effects of HeNe laser irradiation on cutaneous inflammatory lesions caused by the inoculation of 5 x 10(6)/0.1ml yeasts cells into the back footpad of Balb/c mice. HeNe irradiation (lambda=632.8nm, 3mW, incident energy of 3J/cm(2)) was applied at days 7, 8 and 9 post-infection and histological and immunohistochemical analysis were done. Unirradiated animals were used as controls. The results showed that laser-treated mice presented reduction of footpad edema, faster cutaneous wound healing, confluent granuloma, diffuse- and more loosely distributed immunolabeling for TNF-alpha, enhanced labeling of IFN-gamma and any P. brasiliensis form detected, whereas multiple viable fungi were seen in diffuse widespread granulomas obtained from non-treated mice foot-pad. Fungi that were harvested from laser-treated animals presented no capability of growth in vitro as compared to those obtained from non-treated mice. We conclude that HeNe laser irradiation was able to inhibit the progress of inflammatory local reaction produced by P. brasiliensis infection and influence local cytokines production. We suggest that this treatment modality can be a useful coadjuvant tool to be combined with antifungal agents in the treatment of PCM ulcerations. The mechanisms involved in laser therapy of PCM lesions need further investigation. 相似文献
166.
Christel Rotthaus Liana M. Sega 《Transactions of the American Mathematical Society》2006,358(11):4959-4980
Let be an excellent homogeneous Noetherian graded ring and let be a finitely generated graded -module. We consider as a module over and show that the -loci of are open in . In particular, the Cohen-Macaulay locus is Cohen-Macaulay is an open subset of . We also show that the -loci on the homogeneous parts of are eventually stable. As an application we obtain that for a finitely generated Cohen-Macaulay module over an excellent ring and for an ideal which is not contained in any minimal prime of , the -loci for the modules are eventually stable.
167.
Liana Annunziata Consiglia Tedesco Claudio Pellecchia 《Journal of organometallic chemistry》2006,691(8):1505-1514
The synthesis of new organotin compounds of general formula Tip2SnRR′ (Tip = 2,4,6-triisopropylbenzene; R = R′ = CH3 (1); R = R′ = CHCH2 (2); R = CH2Ph, R′ = Br (3); R = R′ = CH2CHCH2 (4)) is described herein. The compounds have been characterized by 1H, 13C, 119Sn NMR, mass spectroscopy and elemental analysis. Characterization by single-crystal X-ray diffraction analysis has been obtained for compounds 2, 3 and 4. The reactivity with ionizing agents has been studied by NMR spectroscopy. Compounds 2 and 4 underwent alkyl abstraction by [(CH3CH2)3Si]+[B(C6F5)4]− affording stable cationic species (2a, 4a). For the cationic specie 4a a π-interaction of the benzyl group to the metal centre was recognized by solution NMR studies. A cationic species (3a) was generated from compound 3 using AgSbF6 as ionizing agent. The cationic species (2a, 3a) exhibited moderate activity as initiator in the cationic polymerization of 1,4-butadiene and good activity in the ring opening polymerization (ROP) of propylene oxide and ε-caprolactone. 相似文献
168.
Necessary and sufficient conditions for a point to be a weak saddle point of a vector valued function (i.e. to be a solution of the vector saddle point problem) are given. Also, an existence result for a vector saddle point to have a solution is given. 相似文献
169.
Donato Pocar Luisa Maria Rossi Franca Scorca Pasqualina Trimarco 《Journal of heterocyclic chemistry》1980,17(5):887-890
Several 5-amino-3-aryl-4-methylene-4,5-dihydroisoxazoles were reacted with methoxide, benzenethiolate, benzenethiol, carboxylic acids and secondary amines. Addition and/or addition-elimination products were obtained. Reaction mechanisms are discussed. 相似文献
170.
1 INTRODUCTION The chemistry of polyoxometalates has been at- tracting much attention due to the richness in their structures, electron and proton storage abilities, ther- mal stability and applications in catalysis, medicine and surface sciences[1~3]. In recent years, the mixed- valence as well as full oxidized vanadium polyoxo- anions have been crystallized with a variety of orga- nic molecules as counteranions[4~8]. However, the guiding principles of the crystal structures of poly- o… 相似文献