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We measured the following variables to investigate the effects of fasting and temperature on swimming performance in juvenile qingbo (Spinibarbus sinensis): the critical swimming speed (Ucrit), resting metabolic rate and active metabolic rate of fish fasting for 0 (control), 1, 2 and 4 weeks at low and high acclimation temperatures (15 and 25 °C). Both fasting treatment and temperature acclimation had significant effects on all parameters measured (P<0.05). Fasting at the higher temperature had a negative effect on all measured parameters after 1 week (P<0.05). However, when acclimated to the lower temperature, fasting had a negative effect on Ucrit until week 2 and on , and metabolic scope (MS, –) until week 4 (P<0.05). The values of all parameters at the lower temperature were significantly lower than those at the higher temperature in the identical fasting period groups except for of the fish that fasted for 2 weeks. The relationship between fasting time (T) and Ucrit was described as Ucrit(15)=−0.302T2−0.800T+35.877 (r=0.781, n=32, P<0.001) and Ucrit(25)=0.471T2−3.781T+50.097 (r=0.766, n=32, P<0.001) at 15 and 25 °C, respectively. The swimming performance showed less decrease in the early stage of fasting but more decrease in the later stage at the low temperature compared to the high temperature, which might be related to thermal acclimation time, resting metabolism, respiratory capacity, energy stores, enzyme activity in muscle tissue and energy substrate utilization changes with fasting between low and high temperatures. The divergent response of the swimming performance to fasting in qingbo at different temperatures might be an adaptive strategy to seasonal temperature and food resource variation in their habitat. 相似文献
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《Inorganica chimica acta》2006,359(4):1023-1030
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Visible absorption and CD spectral and potentiometric studies on the His- and Tyr-containing ternary copper(II) complexes Cu(A)(L-B), where A refers to L-His, D-His, or L-Tyr and B to Lys, Tyr, Trp, Phe, Ala, Val, Arg, Glu, Asn, Gln, Ser, or Thr, were made to study ligand-ligand interactions in the complexes. While the CD spectral magnitudes in the d—d region are additive in the absence of side chain interactions and can be estimated from the magnitudes for the ternary systems involving DL-A or DL-B, deviation from the additivity was observed for Cu(L-His)(L-B) (B = LysH, Tyr, Trp, or Phe) and Cu(L-Tyr)(L-Trp). From the stability constants determined at 25 °C and I = 0.1 M (KNO3), the equilibrium constants, K, for the following hypothetical equilibria were calculated to be large (0.14–0.60) for formation of Cu(L-/D-His)(L-B)(B = Tyr or Trp) and Cu(D-His)(L-Phe) with Cu(en)(L-Ala) as standard: The positive values indicate the stabilization due to the stacking between the imidazole ring of His and the aromatic side chain of L-B. Solvent dependence of the CD spectra for Cu(L-His)(L-LysH) and Cu(L-His) L-Trp) further supported the existence of the intramolecular electrostatic and hydrophobic interactions. 相似文献
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For a given graph G, ε(v) and deg(v) denote the eccentricity and the degree of the vertex v in G, respectively. The adjacent eccentric distance sum index of a graph G is defined as , where is the sum of all distances from the vertex v. In this paper we derive some bounds for the adjacent eccentric distance sum index in terms of some graph parameters, such as independence number, covering number, vertex connectivity, chromatic number, diameter and some other graph topological indices. 相似文献
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Sara Jiménez-Puertas David Sánchez-Artuñedo Marcelino Hermida-López 《Reports of Practical Oncology and Radiotherapy》2018,23(2):121-125