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61.
Fortunati Alessandro Bacigalupo Andrea Lepidi Marco Arena Andrea Lacarbonara Walter 《Nonlinear dynamics》2022,108(2):765-787
Nonlinear Dynamics - The cellular microstructure of periodic architected materials can be enriched by local intracellular mechanisms providing innovative distributed functionalities. Specifically,... 相似文献
62.
Clarissa O. Da Silva Fbio Eduardo C. Teixeira Jos Andr T. Azevedo Edilson C. Da Silva Marco Antonio Chaer Nascimento 《International journal of quantum chemistry》1996,60(1):433-438
The two lower-lying electronic states (3Σ− and 5Σ−) of the BeC, MgC, and CaC molecules were investigated using restricted Hartree-Fock (RHF), generalized valence bond (GVB), and configuration interaction (CI) calculations to establish the relative ordering of those states as a function of the size of the alkaline-earth element. It is shown that as a result of the competition between bonding effects, which predominate for the 3Σ− states, and exchange effects, which stabilize the 5Σ− states, the ordering of these states can be reversed as we move from the Be to the Ca atom. For both the BeC and MgC molecules, the ground state was found to be a triplet X3Σ− state, but for the CaC molecule, the high-spin X5Σ− becomes more stable. © 1996 John Wiley & Sons, Inc. 相似文献
63.
Rosalba Leuci Leonardo Brunetti Antonio Laghezza Luca Piemontese Antonio Carrieri Leonardo Pisani Paolo Tortorella Marco Catto Fulvio Loiodice 《Molecules (Basel, Switzerland)》2022,27(3)
A new series of aryloxyacetic acids was prepared and tested as peroxisome proliferator-activated receptors (PPARs) agonists and fatty acid amide hydrolase (FAAH) inhibitors. Some compounds exhibited an interesting dual activity that has been recently proposed as a new potential therapeutic strategy for the treatment of Alzheimer’s disease (AD). AD is a multifactorial pathology, hence multi-target agents are currently one of the main lines of research for the therapy and prevention of this disease. Given that cholinesterases represent one of the most common targets of recent research, we decided to also evaluate the effects of our compounds on the inhibition of these specific enzymes. Interestingly, two of these compounds, (S)-5 and 6, showed moderate activity against acetylcholinesterase (AChE) and even some activity, although at high concentration, against Aβ peptide aggregation, thus demonstrating, in agreement with the preliminary dockings carried out on the different targets, the feasibility of a simultaneous multi-target activity towards PPARs, FAAH, and AChE. As far as we know, these are the first examples of molecules endowed with this pharmacological profile that might represent a promising line of research for the identification of novel candidates for the treatment of AD. 相似文献
64.
Luis Estrada-Gil Juan C. Contreras-Esquivel Carolina Flores-Gallegos Alejandro Zugasti-Cruz Mayela Govea-Salas Marco A. Mata-Gmez Raúl Rodríguez-Herrera Juan A. Ascacio-Valds 《Molecules (Basel, Switzerland)》2022,27(5)
Rambutan (Nephelium lappaceum L.) is a tropical fruit from Asia which has become the main target of many studies involving polyphenolic analysis. Mexico produces over 8 million tons per year of rambutan, generating a huge amount of agro-industrial waste since only the pulp is used and the peel, which comprises around 45% of the fruit’s weight, is left behind. This waste can later be used in the recovery of polyphenolic fractions. In this work, emerging technologies such as microwave, ultrasound, and the hybridization of both were tested in the extraction of phenolic compounds from Mexican rambutan peel. The results show that the hybrid technology extraction yielded the highest polyphenolic content (176.38 mg GAE/g of dry rambutan peel). The HPLC/MS/ESI analysis revealed three majoritarian compounds: geraniin, corilagin, and ellagic acid. These compounds explain the excellent results for the biological assays, namely antioxidant activity evaluated by the DPPH, ABTS, and LOI (Lipid oxidation inhibition) assays that exhibited great antioxidant capacity with IC50 values of 0.098, 0.335, and 0.034 mg/mL respectively, as well as prebiotic activity demonstrated by a µMax (maximum growth) of 0.203 for Lactobacillus paracasei. Lastly, these compounds have shown no hemolytic activity, opening the door for the elaboration of different products in the food, cosmetic, and pharmaceutical industries. 相似文献
65.
Amyotrophic lateral sclerosis is a progressive and fatal disease that causes motoneurons degeneration and functional impairment of voluntary muscles, with limited and poorly efficient therapies. Alterations in the Nrf2-ARE pathway are associated with ALS pathology and result in aberrant oxidative stress, making the stimulation of the Nrf2-mediated antioxidant response a promising therapeutic strategy in ALS to reduce oxidative stress. In this review, we first introduce the involvement of the Nrf2 pathway in the pathogenesis of ALS and the role played by astrocytes in modulating such a protective pathway. We then describe the currently developed activators of Nrf2, used in both preclinical animal models and clinical studies, taking into consideration their potentialities as well as the possible limitations associated with their use. 相似文献
66.
Electron and proton acceleration in three-dimensional electric and magnetic fields is studied through test particle simulations. The fields are obtained by a three-dimensional magnetohydrodynamic simulation of magnetic reconnection in slab geometry. The nonlinear evolution of the system is characterized by the growth of many unstable modes and the initial current sheet is fragmented with formation of small scale structures. We inject at random points inside the evolving current sheet a Maxwellian distribution of particles. In a relatively short time (less than a millisecond) the particles develop a power-law tail. The acceleration is extremely efficient and the electrons absorb a large percentage of the available energy in a small fraction of the characteristic time of the MHD simulation, suggesting that resistive MHD codes are unable to represent the full extent of particle acceleration. 相似文献
67.
Magnetic-resonance force microscopy is combined with cross-polarization and spin-decoupling NMR techniques to obtain double-resonance NMR signals of micrometer-scaled objects. The effective one-dimensional spatial resolution obtained in our experiments performed on a KPF6 single crystal sample is approximately 0.5 microm. The spectral linewidth of 900 Hz is sample limited. The described double-resonance techniques can introduce new chemical specificity to the magnetic-force sensor. 相似文献
68.
Marco Castrillón López Jaime Muñz Masquó 《International Journal of Theoretical Physics》2007,46(4):1020-1026
It is proved that the Euler–Lagrange equations of a Yang-Mills type Lagragian is independent with respect to the chosen pairing
in the Lie algebra. Moreover, the Hamilton-Cartan equations of these Lagrangians are obtained and proved to be also independent
with respect to the pairing.
PACS Numbers 2003: 02.20.Qs, 02.20.Sv, 02.20.Tw, 02.40.Ma, 02.40.Vh, 11.10.Ef, 11.15.Kc
Mathematics Subject Classification 2000: Primary 70S15, Secondary 58A20, 58E15, 58E30, 70S05, 70S10, 81T13 相似文献
69.
We present an analysis of the temporal evolution of a scientific coauthorship network, the genetic programming network. We find evidence that the network grows according to preferential attachment, with a slightly sublinear rate. We empirically find how a giant component forms and develops, and we characterize the network by several other time-varying quantities: the mean degree, the clustering coefficient, the average path length, and the degree distribution. We find that the first three statistics increase over time in the growing network; the degree distribution tends to stabilize toward an exponentially truncated power-law. We finally suggest an effective network interpretation that takes into account the aging of collaboration relationships. 相似文献
70.
Jaume Llibre Marco Antonio Teixeira Joan Torregrosa 《Mathematical Physics, Analysis and Geometry》2007,10(3):237-249
The goal of this paper is double. First, we illustrate a method for studying the bifurcation of limit cycles from the continuum
periodic orbits of a k-dimensional isochronous center contained in ℝ
n
with n ⩾ k, when we perturb it in a class of differential systems. The method is based in the averaging theory. Second, we consider a particular polynomial differential
system in the plane having a center and a non-rational first integral. Then we study the bifurcation of limit cycles from
the periodic orbits of this center when we perturb it in the class of all polynomial differential systems of a given degree.
As far as we know this is one of the first examples that this study can be made for a polynomial differential system having
a center and a non-rational first integral.
The first and third authors are partially supported by a MCYT/FEDER grant MTM2005-06098-C01, and by a CIRIT grant number 2005SGR-00550.
The second author is partially supported by a FAPESP–BRAZIL grant 10246-2. The first two authors are also supported by the
joint project CAPES–MECD grant HBP2003-0017. 相似文献