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651.
Esteban G. Vega-Hissi Matías F. Andrada Graciela N. Zamarbide Mario R. Estrada Francisco Tomás-Vert 《Journal of molecular modeling》2011,17(6):1317-1323
Quantum chemical methods have been used to study the conformational and electronic properties of sulfanilamide and derivatives
with antibacterial activity. Calculations at B3LYP/6-311++G(3df,2p) level of theory predict the existence of four conformers
for sulfanilamide depending on the orientation of p-amino and amide groups. Focusing on the sulfonamide moiety, amide NH2 and SO2 groups could exist either in an eclipsed or staggered arrangement. Gas-phase results predict the eclipsed conformer to be
most stable but opposite to what has been rationalized previously, no stabilizing hydrogen bonds between those groups has
been found through NBO analysis. When solvent effect is taken into account through the IEF-PCM method, staggered conformer
is preferred; in fact, eclipsed conformation changed when explicit solvent molecules were included. Conformational analysis
of all derivatives has shown two global minima which are specular images. Five out of the seven derivatives studied adopted
a particular minimum energy conformation with very similar geometries. 相似文献
652.
Radim Šumbera Vladimír Mazoch Hana Patzenhauerová Matěj Lövy Jan Šklíba Josef Bryja Hynek Burda 《Acta theriologica》2012,57(2):121-130
Among African mole-rats, the giant mole-rat Fukomys mechowii is the largest social species. Despite several attempts to study a free-living population, information on its biology from
natural habitats is very scarce. We mapped two neighbouring burrow systems of the giant mole-rat in a miombo woodland in Zambia.
We provide information on the size and kin structure of the respective mole-rat families, architecture of their burrow systems,
and characteristics of the food supply and soil around the two mapped and additional ten burrow systems. Both uncovered burrow
systems were very large (total lengths, 2,245 and 743 m), making them the largest burrow systems ever mapped. Food resources
around the additional ten burrow systems had a clumped distribution (standardized Morisita index of dispersion = 0.526), but
a relatively high biomass (298 ± 455 g m−2). This, together with favourable soil conditions even in the advanced dry season (cone resistance, 328 ± 50 N m−2; soil density, 1.36 ± 0.06 g cm−3) indicates relatively hospitable ecological conditions. Both food supply and soil conditions were comparable with the conditions
found in a miombo habitat of the solitary silvery mole-rat in Malawi. This suggests that there are no ecological constraints
which would preclude the solitary life of a subterranean herbivore from the examined habitat. Microsatellite analysis supported
the assumption that giant mole-rats live in monogamous multigenerational families with only one breeding pair of non-related
animals and their offspring. The mean family size is consistent with previous findings on this species and comparable to that
found in other Fukomys species studied thus far. 相似文献
653.
Nadia Lis Jiménez Ignacio Raúl Fosco Gustavo César Nassar Andrés Fernando Sánchez-Restrepo Matías Santiago Danna Luis Alberto Calcaterra 《Agricultural and Forest Entomology》2021,23(1):87-96
- The most commonly used method to control insect pests, such as leaf-cutting ants (LCA) in forest plantations, is the application of chemical insecticides, but their use was forbidden in plantations certified by the Forest Stewardship Council because of their negative effect on the environment.
- A 5-year derogation of their prohibition was obtained in 2016 in Argentina, on the condition that forestry companies reduce pesticide doses by 5% per year and inform the Economic Injury Level (EIL).
- The EIL and the Economic Threshold (ET) were estimated for the first time for the Acromyrmex genus in a Salicaceae forestation. As a model, we used the damage caused by the most detrimental LCA species of Argentina (Acromyrmex lundii) in the first, most critical year of a willow plantation (Salix nigra) in the lower basin of the Paraná River.
- The EIL (8–15 nest/ha) was useful to demonstrate the real magnitude of the damage caused by A. lundii, which justified the need for its control. The ET for profitable production (∼3 nests/ha) would not be operatively applicable in a long-term management program in our study site. This methodology could be extrapolated to other Neotropical forest plantations attacked by Acromyrmex species.
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Serry Mohamed A. Alzamendi Gabriel A. Zañartu Matías Peterson Sean D. 《Biomechanics and modeling in mechanobiology》2023,22(4):1365-1378
Biomechanics and Modeling in Mechanobiology - Neck muscles play important roles in various physiological tasks, including swallowing, head stabilization, and phonation. The mechanisms by which neck... 相似文献