Triatomic continuum resonances for large negative scattering lengths

We study triatomic systems in the regime of large negative scattering lengths which may be more favorable for the formation of condensed trimers in trapped ultracold monoatomic gases as the competition with the weakly bound dimers is absent. The manipulation of the scattering length can turn an excited weakly bound Efimov trimer into a continuum resonance. Its energy and width are described by universal scaling functions written in terms of the scattering length and the binding energy, $B_3$, of the shallowest triatomic molecule. For $a^{-1}<-0.0297 \sqrt{m B_3/\hbar^2}$ the excited Efimov state turns into a continuum resonance.Comment: 4 pages, 4 figure

REMOVED: Application of Lipid Membranes for Triggered-Drug Delivery Using an Alternating Magnetic Field

This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)

Ultrastructural Analysis of Enamel Formation During in vitro Development Using Chemically-Defined Medium

To test the hypothesis that enamel biomineralization is regulated by sequential expression of an intrinsic genetic program, we designed experiments to determine if a serumless, chemically-defined medium is permissive for position-dependent ameloblast differentiation and subsequent enamel tissue-specific biomineralization in vitro. In the absence of serum or other exogenous growth factors, Swiss Webster strain mouse embryonic (15-and 16-days gestation) mandibular first molar tooth organs (cap stage) developed within 21 days in vitro into well-defined molar tooth organs expressing dentine and enamel biomineralization. Analysis of data obtained from von Kossa histochemistry for calcium salt formation, as well as ultrastructural information obtained from x-ray microanalysis, electron diffraction, transmission electron microscopy and scanning electron microscopy documented tissue-specific patterns of calcium hydroxyapatite formation in the absence of scrum within organotypic cultures in vitro. An as yet unknown intrinsic genetic program regulates enamel formation in vitro

Ligand Binding Rate Constants in Heme Proteins Using Markov State Models and Molecular Dynamics Simulations

Computer simulation studies of the molecular basis for ligand migration in proteins allow the description and quantification of the key events implicated in this process as, such as the transition between docking sites, displacements of existing ligands and solvent molecules, and open/closure of specific 'gates', among other factors. In heme proteins, especially in globins, these phenomena are related to the regulation of protein function, since ligand migration from the solvent to the active site preludes ligand binding to the iron in the distal cavity, which in turn triggers the different globin functions. In this work, a combination of molecular dynamics simulations with a Markov-state model of ligand migration is used to the study the migration of O2 and ·NO in two truncated hemoglobins of Mycobacterium tuberculosis (truncated hemoglobin N -Mt-TrHbN- and O -Mt-TrHbO). The results indicate that the proposed model provides trends in kinetic association constants in agreement with experimental data. In particular, for Mt-TrHbN, we show that the difference in the association constant in the oxy and deoxy states relies mainly in the displacement of water molecules anchored in the distal cavity by O2 in the deoxy form, whereas the conformational transition of PheE15 between open and closed states plays a minor role. On the other hand, the results also show the relevant effect played by easily diffusive tunnels, as the ones present in Mt-TrHbN, compared to the more impeded passage in Mt-TrHbO, which contributes to justify the different .NO dioxygenation rates in these proteins. Altogether, the results in this work provide a valuable approach to study ligand migration in globins using molecular dynamics simulations and Markov-state model analysis

BisoGenet: a new tool for gene network building, visualization and analysis

<p>Abstract</p> <p>Background</p> <p>The increasing availability and diversity of omics data in the post-genomic era offers new perspectives in most areas of biomedical research. Graph-based biological networks models capture the topology of the functional relationships between molecular entities such as gene, protein and small compounds and provide a suitable framework for integrating and analyzing omics-data. The development of software tools capable of integrating data from different sources and to provide flexible methods to reconstruct, represent and analyze topological networks is an active field of research in bioinformatics.</p> <p>Results</p> <p>BisoGenet is a multi-tier application for visualization and analysis of biomolecular relationships. The system consists of three tiers. In the data tier, an in-house database stores genomics information, protein-protein interactions, protein-DNA interactions, gene ontology and metabolic pathways. In the middle tier, a global network is created at server startup, representing the whole data on bioentities and their relationships retrieved from the database. The client tier is a Cytoscape plugin, which manages user input, communication with the Web Service, visualization and analysis of the resulting network.</p> <p>Conclusion</p> <p>BisoGenet is able to build and visualize biological networks in a fast and user-friendly manner. A feature of Bisogenet is the possibility to include coding relations to distinguish between genes and their products. This feature could be instrumental to achieve a finer grain representation of the bioentities and their relationships. The client application includes network analysis tools and interactive network expansion capabilities. In addition, an option is provided to allow other networks to be converted to BisoGenet. This feature facilitates the integration of our software with other tools available in the Cytoscape platform. BisoGenet is available at <url>http://bio.cigb.edu.cu/bisogenet-cytoscape/</url>.</p

Structure of exotic three-body systems

The classification of large halos formed by two identical particles and a core is systematically addressed according to interparticle distances. The root-mean-square distances between the constituents are described by universal scaling functions obtained from a renormalized zero-range model. Applications for halo nuclei, $^{11}$Li and $^{14}$Be, and for atomic $^4$He$_3$ are briefly discussed. The generalization to four-body systems is proposed.Comment: Contribution to the International workshop "Critical Stability of Few-Body Quantum Systems". To be published in "Few-Body Systems

Magnetism and Mössbauer study of formation of multi-core γ-Fe2O3 nanoparticles

A systematic investigation of magnetic nanoparticles and the formation of a core-shell structure, consisting of multiple maghemite (γ-Fe2O3) nanoparticles as the core and silica as the shell, has been performed using various techniques. High-resolution transmission electron microscopy clearly shows isolated maghemite nanoparticles with an average diameter of 13?nm and the formation of a core-shell structure. Low temperature Mössbauer spectroscopy reveals the presence of pure maghemite nanoparticles with all vacancies at the B-sites. Isothermal magnetization and zero-field-cooled and field-cooled measurements are used for investigating the magnetic properties of the nanoparticles. The magnetization results are in good accordance with the contents of the magnetic core and the non-magnetic shell. The multiple-core γ-Fe2O3 nanoparticles show similar behavior to isolated particles of the same size.We thank the assistance by Dr. Peter Klavins at the Department of Physics, the University of California Davis, in performing the magnetization measurements. This research was partially supported by the Department of Energy, Office of Nuclear Energy, Nuclear Energy Program, under Grant No. DE-NE000070

Unilateral subthalamotomy in Parkinson's disease: Cognitive, psychiatric and, neuroimaging changes

Unilateral subthalamotomy is an effective treatment for the cardinal motor features of Parkinson's disease (PD). However, non-motor changes possibly associated with right or left subthalamotomy remain unknown. Our aim was to assess cognitive, psychiatric and neuroimaging changes after treatment with unilateral subthalamotomy. Fourteen medicated patients with PD were evaluated before and after (mean 6 months after operation) unilateral subthalamotomy (5 right, 9 left). In addition to motor assessments, cognitive (global cognition and executive functions), psychiatric (apathy, depression, anxiety, mania, hypo- and hyperdopaminergic behaviours, impulsivity), quality of life evaluations and volume of lesions were obtained. After surgery, significant improvement of motor signs was observed. Unilateral subthalamotomy improved general cognitive status, but left subthalamotomy reduced semantic verbal fluency compared to the pre-operative state. Depression and quality of life were improved with both right and left subthalamotomy. However, hyper-emotionality was present after surgery and right subthalamotomy increased impulsivity and disinhibition (on NeuroPsychiatric Inventory and Ardouin Scale for Behaviour in PD), a result linked to larger lesion volumes. We conclude that unilateral subthalamotomy is effective for treating the cardinal motor features of PD and improves mood. Right subthalamotomy is associated with greater risk of impulsivity and disinhibition, while left subthalamotomy induces further impairment of semantic verbal fluency

Evidence for Efimov quantum states in an ultracold gas of cesium atoms

Systems of three interacting particles are notorious for their complex physical behavior. A landmark theoretical result in few-body quantum physics is Efimov's prediction of a universal set of bound trimer states appearing for three identical bosons with a resonant two-body interaction. Counterintuitively, these states even exist in the absence of a corresponding two-body bound state. Since the formulation of Efimov's problem in the context of nuclear physics 35 years ago, it has attracted great interest in many areas of physics. However, the observation of Efimov quantum states has remained an elusive goal. Here we report the observation of an Efimov resonance in an ultracold gas of cesium atoms. The resonance occurs in the range of large negative two-body scattering lengths, arising from the coupling of three free atoms to an Efimov trimer. Experimentally, we observe its signature as a giant three-body recombination loss when the strength of the two-body interaction is varied. We also detect a minimum in the recombination loss for positive scattering lengths, indicating destructive interference of decay pathways. Our results confirm central theoretical predictions of Efimov physics and represent a starting point with which to explore the universal properties of resonantly interacting few-body systems. While Feshbach resonances have provided the key to control quantum-mechanical interactions on the two-body level, Efimov resonances connect ultracold matter to the world of few-body quantum phenomena.Comment: 18 pages, 3 figure

Estudio de caso Baldwin. De un monopolio a la búsqueda del liderazgo

El presente documento describe la experiencia de los autores al desarrollar una estrategia para la empresa Baldwin en el simulador de negocios Capstone en la modalidad de estudio de caso, con el fin de exponer los aprendizajes adquiridos para la obtención de grado de la maestría en administración. El primer capítulo aborda el marco teórico donde se muestran los fundamentos básicos sobre planeación estratégica, gestión y modelo de negocios, se analizan diferentes casos de estudio de empresas que han sido disruptivas en la transformación de la industria. En el segundo capítulo se describen las principales características y funcionamiento del simulador Captone. Por otro lado, se expone el panorama de la industria de sensores y se detalla la estructura de la empresa Baldwin, así como su modelo de negocio y estrategia genérica. En los capítulos del tres al seis se muestran los resultados obtenidos de acuerdo con las decisiones tomadas por el equipo directivo de Baldwin durante los ocho años simulados y se realiza una comparación con los principales competidores en la industria siguiendo la metodología Balanced Scorecard, herramienta definida para evaluar los resultados de la organización. En el capítulo siete se presentan los resultados finales derivados de las estrategias ejecutadas por Baldwin y su competencia. Además, las reflexiones de los autores acerca del paso por la maestría en administración y la modalidad de estudio de caso.ITESO, A.C