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排序方式: 共有169条查询结果,搜索用时 578 毫秒
71.
Chemical analysis of Radix Astragali (Huangqi) in China: a comparison with its adulterants and seasonal variations 总被引:8,自引:0,他引:8
Ma XQ Shi Q Duan JA Dong TT Tsim KW 《Journal of agricultural and food chemistry》2002,50(17):4861-4866
Radix Astragali (root of Astragalus; Huangqi) is a popular traditional Chinese medicine, and Astragalus membranaceus and A. membranaceus var. mongolicus are two commonly used species; however, there are many Astragalus species that could act as adulterants of Radix Astragali. To find the chemical composition of Radix Astragali, the main constituents including flavonoids, saponins, polysaccharides, amino acids, and trace elements were determined in two Radices Astragali, A. membranaceus and A. membranaceus var. mongolicus, and its eight adulterants, Astragalus propinquus, Astragalus lepsensis, Astragalus aksuensis, Astragalus hoantchy, Astragalus hoantchy subsp. dshimensis, Astragalus lehmannianus, Astragalus sieversianus, and Astragalus austrosibiricus. The results showed that the amounts of main constituents such as isoflavonoids and astragalosides varied in different species. In distinction, A. membranaceus and A. membranaceus var. mongolicus contained a higher amount of astragaloside I and IV. In addition, the main constituents of A. membranaceus var.mongholicus changed according to seasonal variation and age of the plant. The chemical composition of different species of Astragalus would provide useful information for the quality control of Radix Astragali. 相似文献
72.
To assess the effects of clearcutting on snowshoe hare (Lepus americanus) relative abundance, we surveyed pellets in 1 m2 circular plots and, vegetation and browse surveys in 4.5 m2 circular plots among four different aged clearcut (30, 20, 10, 5 years post-harvest) and mature forests (>150 years old) in central Labrador, Canada. Data were modelled at three grain sizes: transect (4400 m2), plot (314 m2) and subplot scales (4.5 m2). Betula papyrifera, distance from mature forest edge, tree and herb cover as well as remotely sensed forest inventory data were used as predictors for hare pellets. We found pellet abundance was 5 and 37 times greater (new and old pellets, respectively) in clearcut stands 30 years old than the next highest in 20 year old cuts. There were few hare pellets in the remaining stand ages. B. papyrifera was the most proportionately used browse species and most important of our fine-detailed vegetation in predicting hare pellets. The coarse-detailed, forest inventory and topographic data better predicted hare pellets than the fine-detailed vegetation data. 相似文献
73.
Multivariate principal component analysis to evaluate growth performances in Malabari goats of India
Valsalan Jamuna Sadan Tina Venketachalapathy Thirupathy 《Tropical animal health and production》2020,52(5):2451-2460
Tropical Animal Health and Production - Evaluation of growth performances in Malabari goats was done with body weight and major morphometric traits, viz. body height, body length and chest girth at... 相似文献
74.
Tommaso Vezzosi Caterina Puccinelli Rosalba Tognetti Tina Pelligra Simonetta Citi 《Veterinary radiology & ultrasound》2020,61(5):507-511
Thoracic radiography is a useful technique for the evaluation of cardiac dimensions, especially when echocardiography is not possible. The vertebral left atrial size (VLAS) has recently been proposed as a new radiographic method for quantifying left atrial dimensions in dogs. The aims of this retrospective, reference interval, observational study were to describe values for VLAS in a group of healthy adult dogs and to compare intraobserver and interobserver agreement for VLAS versus vertebral heart score (VHS) methods. Thoracic radiographs of 80 healthy adult dogs were evaluated. Normal left atrial size was determined based on an echocardiographic left atrial‐to‐aorta ratio < 1.6. The VLAS and vertebral heart score values were measured from right lateral radiographs. The correlations between VLAS, the vertebral heart score, and the left atrial‐to‐aorta ratio were evaluated. The effects of body weight, sex, and age were also tested using regression analyses. The median value of VLAS were 1.9, with a reference interval of 1.4‐2.2. A positive correlation was found between VLAS and vertebral heart score values (r = 0.53; P < .0001). No effect of body weight, sex, and age on VLAS was detected. Excellent intraobserver and interobserver agreements were found for both VLAS and vertebral heart score methods (intraclass correlation coefficients ≥ 0.91). Findings from this sample of healthy dogs indicated that VLAS is a repeatable radiographic method for quantifying left atrial size. Further studies are warranted to evaluate this measure in clinically affected dogs. 相似文献
75.
76.
BACKGROUND: Phytophagous mites such as the European red mite, Panonychus ulmi (Koch), are serious pests in European fruit tree orchards, and a number of acaricides are frequently used to control them. Spirodiclofen (Envidor®) has been a commonly used acaricide for several years. In the present study, European field populations collected in 2009 and 2010 were checked for their susceptibility to spirodiclofen by using discriminating dose and full dose response bioassays. RESULTS: In 2009 and 2010, a total of 63 field populations (including winter eggs) of European red mites were collected in different European countries, and in several populations from south‐western Germany a shifting in susceptibility against spirodiclofen was observed. Full dose response bioassays on different developmental stages of field‐collected strains suggested an age‐dependent expression of resistance because eggs remain fully susceptible to spirodiclofen. Artificial selection with spirodiclofen of one of the field strains resulted in resistance ratios of > 7000. Synergism studies suggest a possible role of cytochrome‐P450‐dependent monooxygenases in spirodiclofen detoxification. Most of the other acaricides from different chemical classes displayed no or low cross‐resistance in a spirodiclofen‐selected strain. CONCLUSION: In order to preserve spirodiclofen as an important tool in spider mite resistance management, the efficacy situation should be continuously monitored, and it is suggested that spirodiclofen be alternated with acaricides coming from different mode‐of‐action classes. An observed age‐specific expression of resistance revealed full susceptibility of eggs, so targeting spirodiclofen particularly against eggs is likely to reduce the selection pressures imposed on other life stages. Copyright © 2011 Society of Chemical Industry 相似文献
77.
78.
Enols are common intermediates in hydrocarbon oxidation 总被引:1,自引:0,他引:1
Taatjes CA Hansen N McIlroy A Miller JA Senosiain JP Klippenstein SJ Qi F Sheng L Zhang Y Cool TA Wang J Westmoreland PR Law ME Kasper T Kohse-Höinghaus K 《Science (New York, N.Y.)》2005,308(5730):1887-1889
Models for chemical mechanisms of hydrocarbon oxidation rely on spectrometric identification of molecular structures in flames. Carbonyl (keto) compounds are well-established combustion intermediates. However, their less-stable enol tautomers, bearing OH groups adjacent to carbon-carbon double bonds, are not included in standard models. We observed substantial quantities of two-, three-, and four-carbon enols by photoionization mass spectrometry of flames burning representative compounds from modern fuel blends. Concentration profiles demonstrate that enol flame chemistry cannot be accounted for purely by keto-enol tautomerization. Currently accepted hydrocarbon oxidation mechanisms will likely require revision to explain the formation and reactivity of these unexpected compounds. 相似文献
79.
80.
- The Mediterranean common dolphin (Delphinus delphis), considered to have been very common in the past, had undergone a dramatic decline across most of the basin by the end of 1970s. In the northern Adriatic Sea, one of the regions with most available historical information, the common dolphin is thought to have been the most common and abundant cetacean throughout most of the 20th century. However, by the end of 1970s, it had virtually disappeared from the region and is now considered generally absent from the entire Adriatic Sea.
- This contribution summarizes the occurrence of common dolphins in the Gulf of Trieste and provides a brief review of published records in other parts of the Adriatic Sea.
- Systematic boat surveys in the wider area of the Gulf of Trieste between 2002 and 2019 confirmed that the common bottlenose dolphin (Tursiops truncatus) is the only regularly occurring cetacean species in this area. Despite this, several records of common dolphins were documented in the Gulf of Trieste between 2009 and 2012, through sightings of live animals or recovery of dead stranded animals.
- Dorsal fin markings allowed the photo-identification of some of these, suggesting that at least four different live individuals (three adults and one calf) occurred here in recent times. Most cases involved single adult individuals, but one included a mother-calf pair that was temporarily resident in a port for several months, a behaviour atypical for this species. Photo-identification showed that the presumed mother had previously been sighted in the Ionian Sea in Greece, over 1,000 km from the Gulf of Trieste, making this the longest documented movement for this species worldwide.
- At present, the common dolphin continues to be rare in the region.