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81.
EI Levy DK Resnick PJ Jannetta T Lovely DJ Bissonette 《Canadian Metallurgical Quarterly》1997,27(5):238-241
Hemifacial spasm (HFS), generally a disease of the elderly, is caused by vascular compression of the seventh nerve. Vascular compression is thought to result from atherosclerotic changes within the vessels of the posterior fossa, and therefore rarely presents in childhood. Here we describe our experience with 12 patients with onset of HFS during childhood (age 18 or less) and who had surgical exploration of the cerebellopontine angle. These patients represent less than 1.2% of the patient population with HFS operated upon at this institution during the study period. Nine patients had follow-up data extending over 83 months. All 12 patients were found to have microvascular compression of the seventh nerve at the time of surgery. The most common operative finding was compression of the seventh nerve by a vein, alone or in combination with a branch of the anterior inferior cerebellar artery. At the time of discharge and after a mean follow-up period of 125 months, microvascular decompression resulted in complete relief of spasm in 67% of the patients. 相似文献
82.
83.
DK Bhuyan X Huang G Kuriakose WH Garner KC Bhuyan 《Canadian Metallurgical Quarterly》1997,16(6):519-526
This article takes issue with procedural reductionism, which is the inclination to reduce all matters of judgement and responsibility to the following of some procedure or rule. Two scenarios provide content for a discussion of professional discretion in the context of accountability. The author shows that in professional life there will always be situations that stand beyond the rules of procedures and require the unique judgement of the professional at the time. While this judgement may be determined by the facts available in a situation of uncertainty, it cannot be reduced to the facts (including facts about rules and procedures). The moral judgement will still have an essential indeterminancy about it. 相似文献
84.
A methylene-interrupted C18 keto-acetylenic fatty ester (methyl 12-oxo-9-octadecynoate) was obtained from methyl ricinoleate by bromination-dehydrobromination
followed by oxidation. Reaction of methyl 12-oxo-9-octadecynoate with bis(benzonitrile) palladium(II) chloride, allyl bromide,
or methyl-allyl bromide furnished methyl 8-[5-hexyl-3-allyl-furan-2-yl]-octanoate (1, 56%) or methyl 8-[5-hexyl-3-(2-methyl-allyl)-furan-2-yl]-octanoate (2, 55%). Reaction of methyl 12-oxo-11-chloro-or 11-fluoro-9-octadeyynoate (prepared from methyl santalbate-methyl 11-E-9-octadecynoate, found in sandalwood, Santalum album, seed oil) with bis(benzonitrile) palladium(II) chloride gave methyl 8-(4-fluoro-5-hexyl-furan-2-yl)-octanoate (3, 50%) or methyl 8-(4-fluoro-5-hexyl-furan-2-yl)-octanoate (4, 50%), respectively. And when methyl 12-oxo-11-chloro- or 11-fluoro-9-octadecynoate was treated with a mixture of bis(benzonitrile)
palladium(II) chloride, allyl bromide, or methyl-allyl bromide, the reaction yielded tetrasubstituted C18 furan derivatives, viz, methyl 8-(3-allyl-4-chloro-5-hexyl-furan-2-yl)-octanoate (5, 54%), methyl 8-[4-chloro-5-hexyl-3-(2-methyl-allyl)-furan-2-yl)-octanoate (6, 54%), methyl 8-(3-allyl-4-fluoro-5-hexyl-furan-2-yl]-octanoate (7, 10%), and methyl 8-[4-fluoro-5-hexyl-3-(2-methyl-allyl)-furan-2-yl]-octanoate (8, 10%). The presence of a fluorine atom in the furan derivatives 4, 7, and 8 was readily characterized by the appearance of doublets for carbon nuclei, which were coupled to the fluorine atom
in the 13C NMR spectra. All furan fatty derivatives from this work were characterized by NMR spectroscopic and mass spectrometric analyses.
The yields of compounds 7 and 8 were very low (10%) despite attempts to improve the procedure by increasing the amounts of the reactants and catalyst. 相似文献
85.
Furkan Turgut Chun Yew Chong Mustafa Karaman Woei Jye Lau Mehmet Gürsoy Ahmad Fauzi Ismail 《应用聚合物科学杂志》2023,140(5):e53410
In this study, two different monomers, namely hexafluorobutyl acrylate (HFBA) and diethylaminoethyl methacrylate (DEAEMA) were individually used to modify graphene oxide (GO) nanosheets via environmentally friendly plasma enhanced chemical vapor deposition (PECVD) method. The results from instrumental analyses confirmed the successful deposition of respective functional material onto the nanomaterials. Modified GOs were used as the nano-fillers to develop composite polyethersulfone (PES) ultrafiltration (UF) membrane with improved surface properties for oily solution treatment. All the developed membranes were characterized with a series of analytical instruments to support the findings of membrane filtration performance. The results indicated that the membrane incorporated with DEAEMA-GOs (coated with hydrophilic polymer) could achieve better results in terms of oil rejection, antifouling resistance and water recovery rate than the membrane incorporated with HFBA-GOs (coated with hydrophobic polymer). This is due to the reduced agglomeration between modified GOs as well as better interaction of hydrophilic-coated GOs with polymer membrane. Compared to the pure water flux of the membrane incorporated with unmodified GO, the membrane incorporated with DEAEMA-GO achieve approximately 85% higher value with oil removal rate remained almost unchanged (98.94% rejection). 相似文献
86.
F. Din-Houn Lau 《Sequential Analysis》2013,32(4):458-468
Abstract The change-point problem for the noncentral skew t distribution is studied in this article. An approach based on Schwartz information criterion (SIC) is used to detect the changes of the parameters of this distribution. Simulations are conducted to illustrate the performance of the proposed procedure. The method is successfully applied to the stock returns of several Latin American countries. 相似文献
87.
Xiaohong Yao Chak K. Chan Ngai Ting Lau P. S. Lau Ming Fang 《Aerosol science and technology》2013,47(12):1080-1089
The availability of high time-resolution (1 s full spectrum scan) particle sizers permitted atmospheric researchers to scrutinize the characteristics of ultrafine particles in rapidly varying (perhaps, random) high concentration environments such as roadside, on-road, and tunnels. These data also revealed possible artifacts associated with the slower (~ 30 s or more) scanning sizers when used in this kind of environment. This study discusses sampling rate artifact problems based on simulations using 1 s Engine Exhaust Particle Sizer data taken on a mobile platform. 相似文献
88.
The effects of PE-g-MA as a compatibilizer in binary blends of 70/30 high-density polyethylene/epoxidized natural rubber (HDPE/ENR) have been investigated by means of mechanical analysis and scanning electron microscopy. The special emphasis was given to the role of PE-g-MA in inducing interactions between HDPE and ENR. It has been observed that increasing the amount of PE-g-MA in the blend increases the tensile strength, elongation at break, and impact strength. It is believed that the degree of cross-link increased, which led to improve the interaction between the HDPE and ENR. The optimum stress values are shown in the blend containing 6% PE-g-MA. Scanning electron micrographs (SEM) of the samples also indicated that the addition of compatibilizer decreases the domain size of the dispersed phase. Well-dispersed plastic particles in a rubber matrix were strongly indicated in these samples. The results obtained reveal that the addition of PE-g-MA in HDPE/ENR blend led to an increase in the homogeneity of the blends. 相似文献
89.
90.
This paper discusses a rapid GC-FID technique for the simultaneous quantitative analysis of FFA, MAG, DAG, TAG, sterols, and
squalene in vegetable oils, with special reference to palm oil. The FFA content determined had a lower SE compared with a
conventional titrimetric method. Squalene and individual sterols, consisting of β-sitosterol, stigmasterol, campesterol, and
cholesterol, were accurately quantified without any losses. This was achieved through elimination of tedious conventional
sample pretreatments, such as saponification and preparative TLC. With this technique, the separation of individual MAG, consisting
of 16∶0, 18∶0, and 18∶1 FA, and the DAG species, consisting of the 1,2(2,3)- and 1,3-positions, was sufficient to enable their
quantification. This technique enabled the TAG to be determined according to their carbon numbers in the range of C44 to C56. Comparisons were made with conventional methods, and the results were in good agreement with those reported in the literature. 相似文献