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761.
762.
Minimizing the pain of local anesthesia 总被引:1,自引:0,他引:1
We studied the effect of depth of lidocaine injection into the skin, rate of injection, and temperature of the solution on pain experienced. The intervals of onset and duration of anesthesia were also evaluated. Intracutaneous instillation of lidocaine at body temperature (37 degrees C) is no less painful than injection at room temperature (21 degrees C), but superficial wheal-producing dermal injection is uniformly much more painful than that into the deep dermal-subcutaneous tissue region. Rapid injection almost always hurts more than slow. Full anesthesia to pinprick is produced immediately with superficial injection and is present 5 to 6 minutes after deep injection. We suggest that the best method for minimizing the discomfort of inducing local anesthesia is to use a syringe fitted with a No. 30 needle and to inject the smallest amount necessary slowly into the deep dermal-subcutaneous tissue as the needle is being slowly withdrawn. 相似文献
763.
764.
Eleonora Chiri Chris Greening Rachael Lappan David W. Waite Thanavit Jirapanjawat Xiyang Dong Stefan K. Arndt Philipp A. Nauer 《The ISME journal》2020,14(11):2715
Termite mounds have recently been confirmed to mitigate approximately half of termite methane (CH4) emissions, but the aerobic CH4 oxidising bacteria (methanotrophs) responsible for this consumption have not been resolved. Here, we describe the abundance, composition and CH4 oxidation kinetics of the methanotroph communities in the mounds of three distinct termite species sampled from Northern Australia. Results from three independent methods employed show that methanotrophs are rare members of microbial communities in termite mounds, with a comparable abundance but distinct composition to those of adjoining soil samples. Across all mounds, the most abundant and prevalent methane monooxygenase sequences were affiliated with upland soil cluster α (USCα), with sequences homologous to Methylocystis and tropical upland soil cluster (TUSC) also detected. The reconstruction of a metagenome-assembled genome of a mound USCα representative highlighted the metabolic capabilities of this group of methanotrophs. The apparent Michaelis–Menten kinetics of CH4 oxidation in mounds were estimated from in situ reaction rates. Methane affinities of the communities were in the low micromolar range, which is one to two orders of magnitude higher than those of upland soils, but significantly lower than those measured in soils with a large CH4 source such as landfill cover soils. The rate constant of CH4 oxidation, as well as the porosity of the mound material, were significantly positively correlated with the abundance of methanotroph communities of termite mounds. We conclude that termite-derived CH4 emissions have selected for distinct methanotroph communities that are kinetically adapted to elevated CH4 concentrations. However, factors other than substrate concentration appear to limit methanotroph abundance and hence these bacteria only partially mitigate termite-derived CH4 emissions. Our results also highlight the predominant role of USCα in an environment with elevated CH4 concentrations and suggest a higher functional diversity within this group than previously recognised.Subject terms: Soil microbiology, Biogeochemistry 相似文献
765.
Hartmut Arndt 《International Review of Hydrobiology》1991,76(3):387-396
Analysing the results of various authors recent studies in the pelagic region of the Baltic revealed that protozoan biomass is in the same range or even higher than metazooplankton biomass. The dominant groups of planktonic protozoans are heterotrophic pico- and nanoflagellates (various taxonomic groups), large heterotrophic flagellates (mainly dinoflagellates) and ciliates. Regularly the spring bloom of phytoplankton is accompanied by a maximum of protozoan biomass which declines in early summer as a result of intensive grazing pressure by metazooplankton and changing food conditions. The analysis of results from different stations indicated that biomasses of protozoans increase with an increasing degree of eutrophication. Several trophic levels within the microbial web should be added to the traditional view on the pelagic food web of the Baltic. Our knowledge regarding the quantitative aspect of the microbial matter flux of the Baltic is very limited up to now and complex ecological (and taxonomical) studies using standardized methods including all protozoan components are necessary. Protozoans (various trophic groups and levels), besides bacteria, should be viewed as the metabolically most active heterotrophic component in the pelagic region of the Baltic, their activity should increase with an increasing degree of eutrophication. 相似文献
766.
767.
Stefan Arndt 《Plant Systematics and Evolution》2008,271(3-4):129-142
Due to their ploidy levels, their morphological and anatomical characters and their distribution the central alpine Festuca stricta subsp. bauzanina (2n = 8x = 56) and Festuca ovina var. guinochetii (2n = 10x = 70), both belonging to the Festuca valesiaca group, are raised to the specific level. As a new subspecies Festuca bauzanina subsp. rhaetica is described here. The taxa of the polyploid Festuca valesiaca group are morphologically, anatomically and chorologically characterised and an identification key for these taxa in the
central Alps is presented. 相似文献
768.
769.
Henry C. Arndt William G. Biddlecom George P. Peruzzotti Warren D. Woessner 《Prostaglandins & other lipid mediators》1976,11(3):569-572
The synthesis of prostaglandin analogs incorporating the (2-hydroxycyclooctylidene)methyl moiety in place of the natural C13–C20 sidechain has been accomplished via copper-assisted conjugate addition of the (cyclooctylidene)methyllithium
to the cyclopentenone intermediates
and
. 相似文献
770.