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71.
These years Yuangong copper-bearing intrauterine devices (Cu-IUDs) have been used because of less side effects in use. The corrosion of copper is essential to the success of contraception, and the release behavior of indomethacin from medicated Cu-IUD is related to its therapeutic effect. In this study, analytical methods were established to investigate the release behavior of cupric ion of three kinds of Yuangong Cu-IUDs and indomethacin of medicated Yuangong 220 Cu-IUD. Cu-IUDs were incubated in simulated uterine solution (SUS). The concentrations of cupric ion and indomethacin were analyzed by flame atomic absorption spectrometer (FAAS) for 60 days and UV/vis -3310 spectrophotometer for 60 days, respectively. The morphology of copper after corrosion was characterized by SEM. In addition, we detected cytotoxicity by MTT of L929 mouse fibroblasts cells caused by extracts of the three Yuangong Cu-IUDs. The release behavior of cupric ion for three kinds of Yuangong Cu-IUDs was biphasic, which consisted of the initial burst release and then slow and constant release. In vitro release experiment confirmed a biphasic release of indomethacin from Yuangong 220. The copper wire of Yuangong Cu-IUDs showed uneven corrosion. The RGR value of Yuangong 365 Cu-IUD was smaller than that of medicated Yuangong 220 Cu-IUD and RGR value of medicated Yuangong 220 Cu-IUD was smaller than that of Yuangong 300 Cu-IUD. The cupric ion release and indomethacin release showed biphasic. Indomethacin increased the cupric ion release rate and might diminish the adverse effects caused by burst release of cupric ion. The toxicity grade of these three Yuangong Cu-IUDs was 4. We should canvass the adverse events of Cu-lUDs based on practical experiments, and try our best to reduce the toxicity of Cu-lUDs.  相似文献   
72.
The large scale and distribution of cloud computing storage have become the major challenges in cloud forensics for file extraction. Current disk forensic methods do not adapt to cloud computing well and the forensic research on distributed file system is inadequate. To address the forensic problems, this paper uses the Hadoop distributed file system (HDFS) as a case study and proposes a forensic method for efficient file extraction based on three-level (3L) mapping. First, HDFS is analyzed from overall architecture to local file system. Second, the 3L mapping of an HDFS file from HDFS namespace to data blocks on local file system is established and a recovery method for deleted files based on 3L mapping is presented. Third, a multi-node Hadoop framework via Xen virtualization platform is set up to test the performance of the method. The results indicate that the proposed method could succeed in efficient location of large files stored across data nodes, make selective image of disk data and get high recovery rate of deleted files.  相似文献   
73.
Cold-rolled 2024-T3 sheet alloy was subjected to bobbin-tool friction stir welding (BTFSW). The microstructural characteristics and mechanical properties of the nugget zone in the as-welded state were investigated. The results show that the equiaxed grain size of BTFSW 2024-T3 alloy decreases from 7.6 to 2.8 μm as the welding speed is increased from 80 to 120 mm/min; in addition, fine grains are generated in the nugget zone and the size distribution is non-uniform. All Al2CuMg (S') precipitates dissolve into the Al matrix, whereas Mn-rich phases confirmed as T phases (Al20Cu2Mn3, Al6Mn, or Al3Mn) remain unchanged. The optimized parameters for BTFSW are verified as the rotation speed of 350 r/min and the travel speed of 100 mm/min. The variations in precipitation and dislocation play more important roles than grain size in the nugget zone with respect to influencing the mechanical properties during the BTFSW process. After the BTFSW process, the fracture mode of base material 2024-T3 alloy transforms from ductile rupture to ductile-brittle mixed fracture.  相似文献   
74.
Lethal yellowing (LY) of coconut palm (Cocos nucifera L., Arecaceae) is a disease of economic importance that is caused by the phytoplasma ‘Candidatus Phytoplasma palmae’ and is transmitted by the planthopper Haplaxius crudus (Van Duzee) (Hemiptera: Cixiidae). This study explores the weeds used by H. crudus nymphs and other Cixiidae in a coconut pathosystem in southern Mexico. Nymphs were collected directly from the root system of each weed by hand or with the help of a vacuum after carefully opening the culm. This study included 11 species of weeds: nine Poaceae [Brachiaria decumbens Stapf, B. humidicola (Rendle) Schweick, B. mutica (Forssk.) Stapf, Digitaria abyssinica (Hochst. Ex A. Rich.) Stapf, Eustachys petraea (Sw.) Desv., Leersia hexandra Sw., Panicum laxum Sw., P. maximum Jacq., Paspalum notatum Flüggé]; one Cyperaceae [Cyperus ligularis L.], and one Portulacaceae: [Portulaca pilosa L.]. Brachiaria mutica, E. petraea, B. humidicola, P. maximum were identified as the principal host species for H. crudus nymphs. Brachiaria decumbens, D. abyssinica, and C. ligularis are new host records for the nymphs of H. crudus. Additionally, it was found that H. crudus may coexist with its cogeners H. skarphion Kramer (Cixiidae) and H. caldwelli Kramer (Cixiidae), on B. mutica. On C. ligularis, H. crudus may coexist with Oecleus snowi Ball (Cixiidae) nymphs. These results suggest that in the coconut pathosystem there is a complex of multitrophic interactions that should be considered in integrated management of LY.  相似文献   
75.
Two metamorphic processes, i.e. subsolidus dehydration and partial melting occurring in MORB, metasediments and peridotite of subducted oceanic lithosphere are discussed on the basis of available experimental work and phase equilibrium modeling. Phase diagrams of hydrous MORB show that in most cold subduction P-T (pressure-temperature) regimes a large portion of water in the basic layer has released below the onset of blueschist facies (〈 20 km), and at a depth (60--70 km) of transition from lawsonite blueschist to lawsonite eclogite facies through glaucophane dehydration; only a smaller portion of water will escape from the slab through dehydration of lawsonite and chloritoid in the depth range suitable for arc magma formation; and a very small portion of water stored in lawsonite and phengite will fade into the deeper mantle. The role of amphibole for arc magma formation is still arguable. In cold subduction P-Tregimes, the dehydration of chlorite and talc in AI-poor metasediments, and chloritoid and carpholite in AI-rich metapelites at a depth around 80--100 km will make some con- tributions to the formation of arc magma. Comparatively, dehydration of serpentine in hydrated peri- dotite occurs at depths of 120--180 km, playing an important role in the arc magmatism. Subduction of oceanic crust along warm P-T regimes will cross the solidi at a depth over 80 km, resulting in partial melting under fluid-saturated and fluid-absent conditions in the metasediments involving biotite and phengite, and in the basic rocks involving epidote and amphibole. The melt compositions of the basic crust are adakitic at pressures 〈 3.0 GPa, but become peraluminous granitic at higher pressures.  相似文献   
76.
The global growth of the Internet and the rapid expansion of social networks such as Facebook make multilingual sentiment analysis of social media content very necessary. This paper performs the first sentiment analysis on code-mixed Bambara-French Facebook comments. We develop four Long Short-term Memory (LSTM)-based models and two Convolutional Neural Network (CNN)-based models, and use these six models, Naïve Bayes, and Support Vector Machines (SVM) to conduct experiments on a constituted dataset. Social media text written in Bambara is scarce. To mitigate this weakness, this paper uses dictionaries of character and word indexes to produce character and word embedding in place of pre-trained word vectors. We investigate the effect of comment length on the models and perform a comparison among them. The best performing model is a one-layer CNN deep learning model with an accuracy of 83.23 %.  相似文献   
77.
With supercritical CO2 fluid extraction(SCFE), essential oil was extracted from three cultivars of Xianning osmanthus. The fresh osmanthus flower was processed with a petroleum ether digestion method to produce the extractum. The yields of essential oil and extractum were 0.19 % and 0.13 % (m/m) respectively. The essential oil and fragrance composition and content extracted were analyzed with gas chromatography-mass spectrometer (GC-MS). The result showed that essential oil contained 36.99%(area/total area) of ionone, ionol and 13.11% of linalool; ionone and ionol contained in extractum were as high as up to 33.33%, while linalool up to 21.92%. Whether essential oil or extractum contains only about 40% fat acid and other ester matters. None of environmental estrogen (phthalic ester) was found in fragrance ingredients. The result also showed that the quality of O. fragrans Albus group fragrance in Xianning is better than that produced in Hangzhou and Anhui districts.  相似文献   
78.
A new common phrase scoring method is proposed according to term frequency-inverse document frequency (TFIDF) and independence of the phrase. Combining the two properties can help identify more reasonable common phrases, which improve the accuracy of clustering. Also, the equation to measure the in-dependence of a phrase is proposed in this paper. The new algorithm which improves suffix tree clustering algorithm (STC) is named as improved suffix tree clustering (ISTC). To validate the proposed algorithm, a prototype system is implemented and used to cluster several groups of web search results obtained from Google search engine. Experimental results show that the improved algorithm offers higher accuracy than traditional suffix tree clustering.  相似文献   
79.
80.
The equilibrium reaction between CaO—Al2O3—SiO2—MgO slag and 28MnCr5 molten steel was calculated to obtain the suitable slag composition which is effective for decreasing the oxygen content in molten steel. The dissolved oxygen content [O] in molten steel under different top slag conditions was calculated using a thermodynamic model and was measured using an electromotive force method in slag–steel equilibrium experiments at 1873 K. The relations among [O], the total oxygen content (T.O), and the composition of the slag were investigated. The experimental results show that both [O] and T.O decrease with decreasing SiO2 content of the slag and exhibit different trends with the changes in the CaO/Al2O3 mass ratio of the slag. Increasing the CaO/Al2O3 mass ratio results in a decrease in [O] and an increase in T.O. To ensure that T.O ≤ 20 ppm and [O] ≤ 10 ppm, the SiO2 content should be controlled to <5wt%, and the CaO/Al2O3 mass ratio should be in the range from 1.2 to 1.6.  相似文献   
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