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361.
Osterhaus AD Rimmelzwaan GF Martina BE Bestebroer TM Fouchier RA 《Science (New York, N.Y.)》2000,288(5468):1051-1053
Influenza B virus is a human pathogen whose origin and possible reservoir in nature are not known. An influenza B virus was isolated from a naturally infected harbor seal (Phoca vitulina) and was found to be infectious to seal kidney cells in vitro. Sequence analyses and serology indicated that influenza virus B/Seal/Netherlands/1/99 is closely related to strains that circulated in humans 4 to 5 years earlier. Retrospective analyses of sera collected from 971 seals showed a prevalence of antibodies to influenza B virus in 2% of the animals after 1995 and in none before 1995. This animal reservoir, harboring influenza B viruses that have circulated in the past, may pose a direct threat to humans. 相似文献
362.
Purpose
The purpose of this study was to investigate relationships between chemical and thermal stabilities of Cu–humic complexes. The study of the chemical stability was based on pedological methods used for the determination of the bond strength of metal ions in soils by chemical leaching agents. The samples with various contents of the Cu(II) ions and their bond strength were put to the thermal analysis in order to correlate their thermo-oxidative behavior with their stability determined by leaching.Materials and methods
The humic acid was extracted from the South-Moravian lignite by standard alkaline extraction. The humic sample was used in two different forms: as the solid powder and as the hydrogel prepared by the acidic precipitation of humate. Six various concentrations of copper(II) solutions were used for the complexation of the humic powder and the hydrogel, in order to study the influence of their initial concentration on both the determined stabilities of the prepared complexes. Their chemical stability was assessed in terms of the Cu(II) ions release from the humic acid structure into two different extraction agents (MgCl2 and HCl solutions). Their thermo-oxidative behavior was investigated employing the thermogravimetry.Results and discussion
The complexation capacity of the humic hydrogel was higher in comparison with the humic powder. The amounts extractable from the Cu–humic complexes by the used leaching agents are higher for the humic powder, which shows on the lower chemical stability. The thermal degradation of the prepared complexes proceeds in several steps and this character remains also after the removal of the mobile and the ion-exchangeable fractions by the MgCl2. The elimination of these fractions as well as the extraction of the strongly bound Cu(II) ions shift the thermal degradation to higher temperatures. The incombustible residue increases with the Cu(II) content in the complexes except for the samples extracted by the HCl.Conclusions
The form of humic sample used for the preparation of the Cu–humic complexes influences both the chemical stability and the thermal one. The main reason is probably a better accessibility of the functional groups in the humic gel, which enables forming stronger binding copper(II) ions. The results showed that the thermal and chemical stabilities are closely related, which corresponds with the shift of the thermal degradation to higher temperatures after removing the less stable fractions from the humic complexes. 相似文献363.
Martina?G?b Katharina?Hoffmann Melanie?Lobe Rut?Metzger Sven van?Ooyen Gereon?ElbersEmail author Barbara?K?llner 《Journal of Forest Research》2006,11(2):69-75
Near infrared (NIR) reflectance spectroscopy was tested as a fast method for characterizing the toxic effects of air pollution
on trees. Fagus sylvatica was exposed to known, different levels of ozone during summer of 2003 in plant chambers. Leaves were taken from the plants
and NIR spectra were recorded. In order to derive calibration models, reference analyses were carried out and soluble carbohydrates
were determined by an enzymatic method. Minor components, like α-tocopherol, were measured after solvent extraction using gas chromatography-mass spectrometry. A partial least squares (PLS)
algorithm was used to perform the chemometric analyses. Good or in some cases very good calibration statistics expressed in
terms of root mean square error of cross validation and R2 were obtained for glucose, fructose, sucrose, and α-tocopherol. In addition, a better than expected correlation between the NIR spectra of the leaves and the ozone concentration
in the plant chambers was observed. NIR spectroscopy appears to be a very useful method to simultaneously determine many components
in leaves that are related to the health of trees. It is obviously able to quantitatively describe the changing patterns of
constituents in leaves of trees caused by toxic substances. Thus, NIR spectroscopy can be a very effective tool for environmental
biomonitoring, especially for observation of forests. 相似文献
364.
Martinek B Bago Z Flöck M Hochsteiner W Schilcher F Kofler J 《Veterinary journal (London, England : 1997)》2006,172(1):181-184
Clinical, ultrasonographic, radiographic and pathological findings of a chondrosarcoma diagnosed in an 8-year-old Simmental cow are reported. The primary site was located in the cartilage of the right scapula at the angulus cranialis. The tumour had already spread to the lungs at the time of diagnosis. This is the first report of a bovine scapula chondrosarcoma. 相似文献
365.
OBJECTIVE: To evaluate the neuromuscular blocking and chronotropic effects of rocuronium bromide in cats anaesthetized for surgery. STUDY DESIGN: Prospective clinical trial. ANIMALS: Twenty-two healthy cats of mixed breed presented for ovariectomy (n = 13) or castration (n = 9). Mean body mass (+/-SD) was 3.6 +/- 0.65 kg and mean age was 10.25 +/- 2.63 months. METHODS: Anaesthesia was induced with intravenous (IV) midazolam (0.3 mg kg(-1)), ketamine (3 mg kg(-1)) and butorphanol (0.4 mg kg(-1)). Tracheal intubation was performed and anaesthesia was maintained with isoflurane delivered in 100% oxygen. Neuromuscular function was monitored using acceleromyography applied at the ulnar nerve. This was stimulated by using the train-of-four (TOF) stimulus pattern (2 Hz) delivered every 15 seconds. The first train was made to establish baseline values for the first twitch (T1) and the TOF-ratio (T4:T1). Rocuronium (0.6 mg kg(-1) IV) was given and the following periods were recorded beginning at the end of injection: (1) lag time (LT) - to the first signs of T1 depression; (2) onset time (OT) - to the total ablation of T1; (3) duration of action (T1(25)) - to 25% recovery of the baseline value for T1; (4) T1(50)- to 50% baseline T1 restoration; (5) to TOF-ratios of 0.7 and 0.9. The time taken for T1 to recover from 75% to 25% depression (T1(25-75)) was also recorded. Heart rate (HR) was taken every minute for 15 minutes, beginning 5 minutes before rocuronium was injected. RESULTS: Rocuronium (0.6 mg kg(-1)) had a mean LT of 15.0 +/- 0 seconds, OT of 46 +/- 11 seconds and T1(25) of 13.2 +/- 2.7 minutes. The mean time for TOF 0.7 and 0.9 was 17.3 +/- 5.4 and 20.7 +/- 5.4 minutes respectively. The mean T1(25-75) was 4.8 +/- 2.4 minutes. No significant changes in HR were observed at any of the time intervals recorded. CONCLUSION: Rocuronium is an effective nondepolarizing muscle relaxant in the cat under the clinical conditions of this study. It has a rapid onset, a short duration of action and did not cause significant changes in HR. 相似文献
366.
Agrobiodiversity is an evident outcome of a long-lasting human–nature relationship, as the continuous use, conservation and management of crops has resulted in biological as well as cultural diversity of seeds and breeds. This paper aims to understand the interlocking of formal and informal seed supply routes by considering the dynamic flow of seeds within networks across the intersections of gender, ethnicity and age in South India as social categories structuring human–nature relations. This changing relationship under formal and informal institutional settings has consequences on performance for men and women in rice seed systems. Undertaking an empirical analysis of the organization of seed management and exchange, we seek to shed light on the gendered organization of agrobiodiversity as a social network. The study builds on Net-Map interviews conducted in 2012, embedded in the larger BioDIVA project in the district of Wayanad in Kerala, India. Based on network analysis, the interactive method employed has enabled identification of important actors in the seed system and the characteristics of their relationships. We look into the gendered structure of information exchange regarding seed varieties and actual seed transactions, while also examining clusters of actors collaborating regarding seed supply. Finally, we identify the institutional gap concerning seed sources left by formal and informal institutions, like the availability of varieties. We show how informal and formal seed systems coexist and overlap due to actors moving between systems and argue that the degree and areas of overlap are shaped by gendered human–nature relations. 相似文献