Boardman A.D.,University of Salford |
Grimalsky V.V.,Autonomous University of Morelos |
Kivshar Y.S.,Australian National University |
Koshevaya S.V.,Autonomous University of Morelos |
And 7 more authors.
Laser and Photonics Reviews | Year: 2011
Metamaterial research is an extremely important global activity that promises to change our lives in many different ways. These include making objects invisible and the dramatic impact of metamaterials upon the energy and medical sectors of society. Behind all of the applications, however, lies the business of creating metamaterials that are not going to be crippled by the kind of loss that is naturally heralded by use of resonant responses in their construction. This review sets out some solutions to the management of loss and gain, coupled to controlled and nonlinear behavior, and discusses some critical consequences concerning stability. Under the general heading of active and tunable metamaterials, an international spectrum of authors collaborates here to present a set of solutions that addresses these issues in several directions. As will be appreciated, the range of possible solutions is really fascinating, and it is hoped that these discussions will act as a further stimulus to the field. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Hernandez-Lamoneda R.,Autonomous University of Morelos |
Sanz-Sanz C.,Institute Fisica Fundamental |
Roncero O.,Institute Fisica Fundamental |
Pio J.M.,University of California at Irvine |
And 2 more authors.
Chemical Physics | Year: 2012
We present the first comprehensive ab initio study of the Ne-Br 2 potential energy surfaces and the non-adiabatic couplings between the valence excited electronic states. These ab initio results are used to obtain 3-D approximate potentials for each electronic state, and these potentials are used in a wave packet calculation of the competing electronic predissociation and vibrational predissociation dynamics. The results of this calculation are in excellent agreement with both experimental results and a previous empirical fit to the experiments. The calculations allow us to observe not only the competition between vibrational and electronic dynamics for the dimer, but also the competition between two different electronic channels. Coupling to the 2 g state dominates for the levels studied here, but coupling to the C state is progressively more important for low vibrational levels, and may dominate at levels below which the current results pertain. The ability of ab initio surfaces and couplings to so accurately reproduce experimental data raises the hope of a complete understanding of the VP and EP dynamics for other Rg-halogen dimers. Success in the case presented here is largely due to the fact that the VP dynamics for the vibrational levels in this study are in the simple, direct regime. Understanding the simple case so thoroughly provides new hope that the more complicated examples, such as ArI 2 and NeCl 2, for which experiment and theory are not currently in accord, may yet yield to analysis. © 2011 Elsevier B.V. All rights reserved.
Sanz-Sanz C.,Institute Fisica Fundamental |
Sanz-Sanz C.,University of Birmingham |
Roncero O.,Institute Fisica Fundamental |
Hernandez-Lamoneda R.,Autonomous University of Morelos |
And 3 more authors.
Journal of Chemical Physics | Year: 2010
Recently, the predissociation lifetimes of the NeBr2 (B) complex for different initial vibrational excitation (10 ≤ v′ ≤ 20) have been measured using time-resolved optical pump-probe spectroscopy [Taylor, J. Chem. Phys., 132, 104309 (2010)]. In the vibrational interval studied, the vibrational predissociation (VP) proceeds by the transfer of a single vibrational quantum and the lifetimes are expected to decrease smoothly with increasing v′, as predicted by the energy gap law. However, the experimental lifetimes show strong oscillations with v′, which were attributed to the occurrence of electronic predissociation into two possible dissociative electronic states of Br2 (1g, 2g), based on a Franck-Condon spectator model. In this work we reproduce the experimental findings by performing full three-dimensional wave packet calculations for the competition of vibrational and electronic predissociation, including the B (0u +), 2g, and C (1 u) electronic states. Model potential energy surfaces were used based on previous theoretical simulations of the VP dynamics on the B state and on ab initio calculations on the NeCl2 related system. Thus, only two parameters, the strength of the electronic couplings, are fit to achieve the excellent theoretical/experimental agreement. © 2010 American Institute of Physics.
PubMed | Autonomous University of Morelos, Regional General Hospital No 1, Mexican Society of Bioelectromagnetism, Monterrey Institute of Technology and Autonomous University of Nuevo León
Type: Clinical Trial, Phase II | Journal: Archives of medical research | Year: 2015
Cellular and animal models investigating extremely low frequency magnetic fields (ELF-MF) have reported promotion of leukocyte-endothelial interactions, angiogenesis, myofibroblast and keratinocyte proliferation, improvement of peripheral neuropathy and diabetic wound healing. In humans, it has also been reported that systemic exposure to ELF-MF stimulates peripheral blood mononuclear cells, promoting angiogenesis and healing of chronic leg ulcers. The aim of the study was to investigate the effect of exposing different blood volumes to specific ELF-MFs (120Hz sinusoidal waves of 0.4-0.9mT RMS) to induce healing of diabetic foot ulcers (DFUs).Twenty six diabetic patients with non-responsive DFUs were divided into two exposure groups to receive treatment and record healing time. The forearm group, exposed to ELF-MF 2h/day, twice weekly (3.6l of blood/session); and the thorax group, exposed 25min/day, 2 times/week (162.5l of blood/session). Treatment period was 100days or upon complete healing. Ulcer recurrences and adverse effects were investigated during short-term (<1year) and long-term (3.4-7.8years) follow-up.Mean healing time was 61.4833.08days in the forearm group and 62.5629.33days for the thorax group. No adverse effects or ulcer recurrences in the original ulcer site were reported during treatment, the short-term follow-up period or the long-term follow-up period in both groups.Healing time was independent of the amount of blood exposed to ELF-MF used in this trial. ELF-MFs are effective and safe and could be applied to non-healing DFUs in conjunction with other preventive interventions to reduce DFUs complications.
Estupinn-Lopez F.H.,Grupo Mexico |
Almeraya-Calderon F.,Grupo Mexico |
Bautista Margulis R.G.,Juarez Autonomous University of Tabasco |
Baltazar Zamora M.A.,University of Veracruz |
And 3 more authors.
International Journal of Electrochemical Science | Year: 2011
The use of electrochemical noise (EN) technique for the investigation and monitoring of corrosion has allowed many interesting advances in the corrosion science in recent years. A special advantage of EN measurements includes the possibility to detect and analyses the early stages of localized corrosion. However, the understanding of the electrochemical information included in the EN signal is actually very limited. This work shows the results obtained from EN measurements for different materials that exhibit pitting corrosion. The obtained transients in potential and current time, correlates with the scanning electron microscopy (SEM) surface analysis. Electrochemical measurements were made at different exposure times in order to obtain any correlation. The used materials were austenitic 316 stainless steel and 2205 duplex alloy, immersed in ferric chloride (FeCl3) and sodium chloride (NaCl) electrolytes. SEM analysis shows that the observed transients in the time series really correspond to the activity of pit nucleation developed on the surface of the electrodes. © 2011 by ESG.
Rapoport Yu.,Taras Shevchenko National University |
Boardman A.,University of Salford |
Grimalsky V.,Autonomous University of Morelos |
Selivanov Yu.,Ukrainian Academy of Sciences |
Kalinich N.,Taras Shevchenko National University
International Conference on Mathematical Methods in Electromagnetic Theory, MMET | Year: 2012
Tunable, nonlinear and active metamaterials are discussed, as a basis of optical instrumentation and signal processing such as filters, birefringent devices, lenses etc. The new method for modeling nonlinear field and energy concentrators is reported, which includes the combination of the new version of complex geometrical optics (CGO) and full-wave nonlinear electromagnetic solution (FWNES) used in different regions of a concentrator and matching of these solutions. Nonlinear concentrators based on both isotropic and hyperbolic metamaterials are discussed. The new strongly nonlinear phenomena- nonlinear focusing switching, taking place when input amplitude of concentrated rays/beams exceeds some threshold value, is found in both types of the field concentrators and searched. © 2012 IEEE.
Ramirez-Solis A.,Autonomous University of Morelos |
Novaro O.,National Autonomous University of Mexico
Foundations of Chemistry | Year: 2014
In a recent paper in this Journal, one of us argued against placing He above Be in Mendeleiev's system of the elements. In it the goal was to dispute the notion that in Mendeleiev's system of the elements the location of He should in fact lie above Be, which has a very similar electronic configuration, rather than above the noble gas column. That paper was based on rather old, Hartree-Fock limit studies on the strikingly limited non-additive contributions in the He3 and He4 systems in contrast with the much larger non-additivity obtained for the Be3, Be4 and Be5 oligomers. In a recent benchmark multireference Averaged Quadratic Coupled Cluster results on Be2 and Be3 we showed that the delocalized non-additive contribution comprises 94 % of the binding energy of Be3. Here we use this and other pertinent information (drawn from the same paper) to conclude that He may not be associated with Be in Mendeleiev's Table, despite their quite similar spectroscopic ground states. Furthermore, we use the new results to show that the large non-additivity implies that less than 2 % of the Be3 binding is located in each Be pair contained within the Be trimer. The rest of the interaction energy is necessarily delocalized over all three Be atoms. This might actually announce the bulk properties (i.e. "the electron gas") that in solid-state physics explain the large electric and heat conduction for the solid Be metal. Thus, in the case of beryllium the metallic characteristics are already evident in Be3, a far cry from the monoatomic helium gas. © 2012 Springer Science+Business Media Dordrecht.
Alcala R.E.,Autonomous University of Morelos |
Alonso R.L.,Autonomous University of Morelos |
Gutierrez-Granados G.,National Autonomous University of Mexico
Botanical Sciences | Year: 2014
The understanding of processes affecting the regeneration and coexistence of tree species is of high concern in tropical landscapes disturbed by anthropogenic activities. In this study, we evaluated the seed shadow of eight small remnant Swietenia macrophylla trees to determine the possible consequences of selective logging on the first stages of natural regeneration. We expected to find a restricted dispersal ability and a marked loss of seeds due to biotic interactions. To test this, seed shadow per tree was quantified along four radial transects (30 × 1 m) that provided 960-1m2 squares for sampling. The wind direction and some tree characteristics as diameter at breast height and crown projection area were also considered as factors influencing seed shadow. We also scored the number of seeds predated or infested by fungi. In total, 540 seeds were found along transects. Around 86.1% of the 960 squares presented 0 or 1 seed, whereas 80% of the seeds were found within the first 20 m from the parent tree. The number of seeds lost through biotic interactions regressed on the distance to the parent tree fitted a quadratic model that explained 52.4% of the total variance. These results suggest that small remnant S. macrophylla trees display low dispersal ability caused by a restricted seed shadow and a high rate of seed damaged produced by biotic interactions. Therefore, removal of largest trees for trading could be negatively impacting the first stages of the natural regeneration of this high value species. Consequently, harvesting could threat the local permanence of S. macrophylla in these managed forests of the Mayan zone.
Rodriguez-Aguilar G.,Colegio de Mexico |
Orozco-Lugo C.L.,Autonomous University of Morelos |
Vleut I.,Colegio de Mexico |
Vazquez L.-B.,Colegio de Mexico
Urban Ecosystems | Year: 2016
Activity and species-specific responses of insectivorous bats in different urban-forest conditions provides a general perspective on the adaptability and vulnerability of bat species towards urbanization intensity. Here we evaluated species richness and activity patterns of aerial insectivorous bats across an urbanized landscape in the highlands of Chiapas, in Mexico. Acoustic monitoring of echolocation calls was conducted for 27 nights over a period of four months. Species richness and relative activity of insectivorous bats were estimated in a landscape with different conditions of urbanization intensity: urban areas, non-urban and forest areas. We identified a total of 14 bat species and three phonotypes. Bat species richness and relative activity was similar (X2 = 0.568, gl = 2, p > 0.05), but species composition differed among conditions. We observed a significant higher occurrence of Bauerus dubiaquercus, Eptesicus brasiliensis and Myotis californicus in forest sites. Urban sites presented higher occurrence of Molossus rufus and phonotype Molossidae 2, while non-urban sites presented a higher occurrence of Eptesicus furinalis and phonotype Molossidae 2. We were able to identify bat species according to their relative activity in relation todifferent landscape conditions. Species of the Molossidae family presented the highest activity in urban sites, which was positively affected by the number of streetlights, while species of the Vespertilionidae presented the highest activity in forest sites, which was positively related totree density. While urbanization tends to diminish native biodiversity and alter faunal communities, our results show a similar richness and relative activity of aerial insectivorous bats along the urban ecosystem. The effect of urbanization intensity becomes more apparent in species-specific bat activity; the response of species towards particular habitat conditions depends on local habitat quality and characteristics (i.e., presence of streetlights, vegetation cover and tree density). © 2016 Springer Science+Business Media New York
PubMed | Autonomous University of Morelos and Autonomous University of Nuevo León
Type: Journal Article | Journal: Oncology letters | Year: 2017
Differentiation induction therapy is an attractive approach in leukemia treatment due to the fact that in blast crisis stage, leukemic cells lose their differentiation capacity. Therefore, it has been proposed as a therapeutic strategy to induce terminal differentiation of leukemic blast cells into a specific lineage, leading to prevention of high proliferation rates. The aim of the present study was to demonstrate the potential of cell differentiation and death induced by bovine dialyzable leukocyte extract (bDLE) in the K562 cell line. For this purpose K562 and MOLT-3 human leukemic cell lines and primary human monocytes and murine peritoneal macrophages were exposed to bDLE, phorbol myristate acetate (PMA) and dimethyl sulfoxide for 96 h, and the viability, proliferation and cell cycle were evaluated. To determine the lineage that led to cell differentiation, Romanowsky staining was performed to observe the morphological changes following the treatments, and the expression of the surface markers cluster of differentiation (CD)14