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1.
Maria Esmeralda C. de Sousa Valria Wanderley-Teixeira lvaro A.C. Teixeira Herbert A.A. de Siqueira Fbio A.B. Santos Luiz C. Alves 《Micron (Oxford, England : 1993)》2009,40(7):743-749
The insect midgut has ultimately been the focus of researches tempting to control insect pests because alterations in the insect gut may affect not only its development, but also physiological events such as nutrient absorption and transformation. The objective of the present work was to describe morphologically, histochemically, and ultrastructurally the larva midgut of Alabama argillacea (Hübner) (Lepidoptera: Noctuidae), a cotton key pest in Brazil. Light and electronic transmission microscopy was used to obtain images from midgut sections of late fourth-instar larvae of A. argillacea. In general, the morphology, histochemistry, and ultrastructure characteristics of A. argillacea midgut follow that described in the literature for other lepidopteran species. However, the results showed a mitochondrial polymorphism and branched microvilli, which suggest an ultrastrucutural and physiological modification possibly associated with a high absorption and secretion activity by the columnar cells of this species. This intense activity may favor a faster response related to the action of ingested microbial agents and/or toxins, and can explain the high susceptibility of A. argillacea to the agents of control such as the toxin of Bacillus thuringiensis. 相似文献
2.
Acid-catalyzed cyclization of D-mannitol followed by isopropylidenation furnished 2,5-anhydro-1,3-O-isopropylidene-D-glucitol, conveniently isolated by dry column vacuum chromatography. 相似文献
3.
4.
Adriano Almeida Gonçalves Siqueira Rodrigo Nicoletti Nicklas Norrick Kátia Lucchesi Cavalca Helio Fiori de Castro Jens Bauer Fadi Dohnal 《Journal of sound and vibration》2012,331(10):2220-2232
Linear parameter varying (LPV) control is a model-based control technique that takes into account time-varying parameters of the plant. In the case of rotating systems supported by lubricated bearings, the dynamic characteristics of the bearings change in time as a function of the rotating speed. Hence, LPV control can tackle the problem of run-up and run-down operational conditions when dynamic characteristics of the rotating system change significantly in time due to the bearings and high vibration levels occur. In this work, the LPV control design for a flexible shaft supported by plain journal bearings is presented. The model used in the LPV control design is updated from unbalance response experimental results and dynamic coefficients for the entire range of rotating speeds are obtained by numerical optimization. Experimental implementation of the designed LPV control resulted in strong reduction of vibration amplitudes when crossing the critical speed, without affecting system behavior in sub- or super-critical speeds. 相似文献
5.
Anaí Duarte Wilson Cunico Claudio M.P. Pereira Alex F.C. Flores Rogério A. Freitag Geonir M. Siqueira 《Ultrasonics sonochemistry》2010,17(2):281-283
An ultrasound-enhanced method has been developed for the synthesis of a variety of thioesters from benzoyl chlorides and 2-mercaptobenzoxa(thia)zoles. Applying this methodology, 14 compounds were synthesized in excellent yields. 相似文献
6.
Lima Héstia Raíssa Batista Reis Nascimento Débora Siqueira Sussuchi Eliana Midori d’Errico Francesco de Souza Susana Oliveira 《Journal of Sol-Gel Science and Technology》2017,81(3):797-805
Journal of Sol-Gel Science and Technology - Magnesium-tetraborates and lithium-tetraborates are excellent detectors for ionizing radiation. However, manufacturing these crystalline structures is... 相似文献
7.
Summary In this paper we discuss the existence of compact attractor for the abstract semilinear evolution equation u=Au+f(t, u); the results are applied to damped partial differential equations of hyperbolic type. Our approach is a combination of Liapunov method with the theory of -eontractions. 相似文献
8.
Dina L. Kinoshita Luiz G. Ferreira Manoel L. De Siqueira 《International journal of quantum chemistry》1985,28(1):85-101
This is the third paper on the cellular method for polyatomic systems. We show how to deal with nonspherical Coulomb potentials. We also show how to modify the variational expression for the energy eigenvalues so as to obtain a faster convergence in the angular momentum series for the wavefunctions. We apply both techniques to the self-consistent calculation of SF6. Contrary to what we obtained in CH4 and SiH4, the cellular method cannot yield the correct equilibrium interatomic distance in the present case. The calculated ionization potentials are in the correct order but are all shifted by 2–3 eV. This shift is attributed to the wrong expression for exchange correlation. 相似文献
9.
Simas ER Gehlen MH Pinto MF Siqueira J Misoguti L 《The journal of physical chemistry. A》2010,114(47):12384-12390
Polyfluorene end-capped with N-(2-benzothiazole)-1,8-naphthalimide (PF-BNI) is a highly fluorescent material with fluorescence emission modulated by solvent polarity. Its low energy excited state is assigned as a mixed configuration state between the singlet S(1) of the fluorene backbone (F) with the charge transfer (CT) of the end group BNI. The triexponential fluorescence decays of PF-BNI were associated with fast energy migration to form an intrachain charge-transfer (ICCT) state, polyfluorene backbone decay, and ICCT deactivation. Time-resolved fluorescence anisotropy exhibited biexponential relaxation with a fast component of 12-16 ps in addition to a slow one in the range 0.8-1.4 ns depending on the solvent, showing that depolarization occurs from two different processes: energy migration to form the ICCT state and slow rotational diffusion motion of end segments at a longer time. Results from femtosecond transient absorption measurements agreed with anisotropy decay and showed a decay component of about 16 ps at 605 nm in PF-BNI ascribed to the conversion of S(1) to the ICCT excited state. From the ratio of asymptotic and initial amplitudes of the transient absorption measurement, the efficiency of intrachain ICCT formation is estimated in 0.5, which means that, on average, half of the excited state formed in a BNI-(F)(n)-BNI chain with n = 32 is converted to its low energy intrachain charge-transfer (ICCT) state. 相似文献
10.
Anderson N. Mendes Isabela Hubber Mônica Siqueira Gleyce Moreno Barbosa Davyson de Lima Moreira Carla Holandino José Carlos Pinto Marcio Nele 《Macromolecular Symposia》2012,319(1):34-40
Summary: This work aimed to produce poly(methyl methacrylate) nanoparticles for use in drug encapsulation. The polymer nanoparticles were produced using miniemulsion polymerization technique. Monomer miniemulsion showed moderate stability and polymer average particle size was about 90 nm. PMMA nanoparticles were tested for toxicity in human leukemic cell strain K562 and they did not show any adverse effect on cell viability. Therefore, poly(methyl methacrylate) nanoparticles are suitable to encapsulate antitumor agents. 相似文献