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排序方式: 共有100条查询结果,搜索用时 31 毫秒
1.
Acquisition of Resistance to Extended-Spectrum Cephalosporins by Salmonella enterica subsp. enterica Serovar Newport and Escherichia coli in the Turkey Poult Intestinal Tract
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Ankur Srivastava Gargi Mishra Kshitij RB Singh Jay Singh Rampal Pandey Mrituanjay D. Pandey 《Luminescence》2023,38(7):1347-1357
Rare earth metals play a conspicuous role in magnetic resonance imaging (MRI) for detecting cancerous cells. The alkali metal potassium is a neurotransmitter in the sodium–potassium pump in biomedical sciences. This unique property of rare earth metals and potassium drew our attention to carry forward this study. Therefore, in this work, previously synthesized potassium (K) complexes formed by the reflux of 4-N,N-dimethylaminobenzoic acid (DBA) and potassium hydroxide in methanol, and named [(μ2–4-N,N-dimethylaminobenzoate-κO)(μ2–4-N,N-dimethylaminobenzoic acid-κO)(4-N,N-dimethylaminobenzoic acid-κO) potassium(I) coordination polymer)] were treated hydrothermally with La2O3 nanomaterials to obtain a nanohybrid La2O3/K-complex. After that, the K-complex was analyzed using single-crystal X-ray diffraction and 1H and 13C NMR spectroscopy. In addition, the structural and morphological properties of the as-prepared nanostructured La2O3/K-complex were also characterized, which involved an investigation using X-ray diffraction (XRD)spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic force spectroscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. After this, the electrochemical redox behaviour of the synthesized nanohybrid material was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Therefore, the results from these studies revealed that the as-prepared material was a La2O3/K-complex that has a promising future role in sensing various analytes, as it showed effective electrocatalytic behaviour. 相似文献
4.
The predatory copepod Mesocyclops edax is an important componentof many zooplankton communities where it typically makes extensivedid vertical migrations. To describe the effect of light onadults we measured their photoresponses in the laboratory. Theresponse spectrum is characterized by a wide plateau of greatestsensitivity from about 480 580 nm. These animals areadapted to perceive light during the day since their regionof maximum sensitivity overlaps the spectral region of highestquantal intensity underwater (575 700 nm). The thresholdintensity for positive phototaxis by dark adapted animals wasabout 5 x 101 Wm2 at 540 nm, and they were positivelyphototactic up to an intensity of 5 x 101 Wm2.Above this intensity phototaxis is no longer observed. Light-adaptedanimals were less sensitive than dark-adapted, but their generalpattern of response to light intensity did not differ. Thereis no rhythm in phototaxis. Their photoresponses may providea mechanism for controlling vertical migration so as to minimizeexposure to planktivorous fish.
1Contribution No. 1375-AEL from UM-CEES, Appalachian EnvironmentalLaboratory. 相似文献
5.
Richard B. Forward Jr Elizabeth Freeman Kristen Gall Katie Saba 《Marine and Freshwater Behaviour and Physiology》2013,45(5):305-319
The supratidal amphipod Talorchestia longicornis Say has a circadian rhythm in activity, in which it is active on the substrate surface at night and inactive in burrows during the day. The present study determined: (1) the circadian rhythms in individual versus groups of amphipods; (2) the range of temperature cycles that entrain the circadian rhythm; (3) entrainment by high-temperature cycles versus light?:?dark cycles, and (4) seasonal substrate temperature cycles. The circadian rhythm was determined by monitoring temporal changes in surface activity using a video system. Individual and groups of amphipods have similar circadian rhythms. Entrainment occurred only to temperature cycles that included temperatures below 20°C (10–20, 15–20, 17–19, 15–25°C) but not to temperatures above 20°C (20–25, 20–30°C), and required only a 2°C temperature cycle (17–19°C). Diel substrate temperatures were above 20°C in the summer and below 20°C during the winter. Upon simultaneous exposure to a diel high-temperature cycle (20–30°C) and a light?:?dark cycle phased differently, amphipods entrained to the light?:?dark cycle. Past studies found that a temperature cycle below 20°C overrode the light?:?dark cycle for entrainment. The functional significance of this change in entrainment cues may be that while buried during the winter, the activity rhythm remains in phase with the day?:?night cycle by the substrate temperature cycles. During the summer, T. longicornis switches to the light?:?dark cycle for entrainment, perhaps as a mechanism to phase activity precisely to the short summer nights. 相似文献
6.
Two silicone coatings have been evaluated for barnacle adhesion. One coating is an unfilled hydrosilation cured polydimethylsiloxane (PDMS) network, while the other is a room temperature vulcanized (RTV), filled, ethoxysiloxane cured PDMS elastomer, RTV11?. The adhesion strength of one species of barnacle, Balanus eburneus, to the hydrosilation coatings is in the range of 0.37–0.60 kg cm‐2 while the corresponding range for RTV11 is 0.64–0.90 kg cm‐2. The easier release of B. eburneus from the hydrosilation cured network compared to RTV11 is discussed in relationship to differences in bulk and surface properties. Preliminary results suggest bulk modulus may be the most important parameter in determining barnacle adhesion strength. In light or mechanical property analysis, a re‐evaluation of surface properties and chemical stability is presented. 相似文献
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Rajendra P Sujatha H Devendranath D Gunasekaran B Sashidhar R Subramanyam C Channakeshava 《Biomagnetic research and technology》2004,2(1):1
BACKGROUND: There are several reports that indicate a linkage between exposure to power frequency (50 - 60 Hz) magnetic fields with abnormalities in the early embryonic development of the chicken. The present study was designed to understand whether power frequency electromagnetic fields could act as an environmental insult and invoke any neurochemical or toxicological changes in developing chick embryo model. METHODS: Fertilized chicken eggs were subjected to continuous exposure to magnetic fields (50 Hz) of varying intensities (5, 50 or 100 microT) for a period of up to 15 days. The embryos were taken out of the eggs on day 5, day 10 and day 15. Neurochemical (norepinephrine and 5-hydroxytryptamine) and amino acid (tyrosine, glutamine and tryptophan) contents were measured, along with an assay of the enzyme glutamine synthetase in the brain. Preliminary toxicological investigations were carried out based on aminotransferases (AST and ALT) and lactate dehydrogenase activities in the whole embryo as well as in the liver. RESULTS: The study revealed that there was a significant increase (p < 0.01 and p < 0.001) in the level of norepinephrine accompanied by a significant decrease (p < 0.01 and p < 0.001) in the tyrosine content in the brain on day 15 following exposure to 5, 50 and 100 microT magnetic fields. There was a significant increase (p < 0.001) in glutamine synthetase activity resulting in the significantly enhanced (p < 0.001) level of glutamine in the brain on day 15 (for 100 microT only). The possible mechanisms for these alterations are discussed. Further, magnetic fields had no effect on the levels of tryptophan and 5-hydroxytryptamine in the brain. Similarly, there was no effect on the activity of either aminotransferases or lactate dehydrogenase in the whole embryo or liver due to magnetic field exposure. CONCLUSIONS: Based on these studies we conclude that magnetic field-induced changes in norepinephrine levels might help explain alterations in the circadian rhythm, observed during magnetic field stress. Also, the enhanced level of glutamine can act as a contributing factor for developmental abnormalities. 相似文献
9.
Forward RB Welch JM Young CM 《Journal of experimental marine biology and ecology》2000,248(2):225-238
Larval release and photobehavior were studied in the colonial ascidian Polyandrocarpa zorritensis. The test hypothesis was that if larval release is induced by light, then larvae should be attracted to settlement areas where light is sufficient for larval release. Light induced larval release but the time course varied with light intensity. As the intensity of either sunlight or blue-green light decreased (1) the time until the beginning of larval release (latency) became longer, (2) the mean time of larval release increased, and (3) the time interval over which larvae were released increased. The threshold light intensity to induce larval release in blue-green light (8.75x10(12) photons cm(-2) s(-1)) was lower than that in sunlight (3.6x10(13) photons cm(-2) s(-1)). Light induced larval release was not affected by currents up to 15 cm s(-1). Larvae aggregate in light when given a choice between light and dark. This response did not vary with larval age. The lowest light intensity, at which larvae could distinguish between light and dark was 5.0x10(12) photons cm(-2) s(-1) in blue-green light and 2.9x10(14) photons cm(-2) s(-1) in sunlight. Thus, the hypothesis is supported because larvae are attracted to areas where light intensity is sufficient for larval release. 相似文献
10.
The endoplasmic reticulum (ER) molecular chaperone, BiP, plays a role in the cotranslational translocation and subsequent
folding and assembly of newly synthesized proteins targeted to the ER and secretory pathway. The sequence encoding a Douglas-fir
(Pseudotsuga menziesii [Mirb] Franco) BiP homologue (PmBiP) was identified by differential screening of a seedling cDNA library. Southern blotting
indicated that PmBiP is most likely present as a single copy. The deduced amino acid sequence of PmBiP contains an HEEL tetrapeptide
sequence which functions to retain PmBiP in the ER and is different from HDEL commonly found in angiosperm plant BiPs. Amino
acid sequence alignment and phylogenetic analysis show that PmBiP is highly similar to other plant BiPs yet forms a distinct
phylogenetic subgroup which is separate from the angiosperm BiPs. Northern and western blotting revealed that PmBiP is subject
to developmental regulation during seed development, germination, and early seedling growth and is seasonally regulated in
needles of young seedlings.
Received: 21 February 2000 / Accepted: 13 April 2000 相似文献