388 research outputs found
Consistent Probabilistic Description of the Neutral Kaon System
The neutral Kaon system has both CP violation in the mass matrix and a
non-vanishing lifetime difference in the width matrix. This leads to an
effective Hamiltonian which is not a normal operator, with incompatible
(non-commuting) masses and widths. In the Weisskopf-Wigner Approach (WWA), by
diagonalizing the entire Hamiltonian, the unphysical non-orthogonal
"stationary" states are obtained. These states have complex
eigenvalues whose real (imaginary) part does not coincide with the eigenvalues
of the mass (width) matrix. In this work we describe the system as an open
Lindblad-type quantum mechanical system due to Kaon decays. This approach, in
terms of density matrices for initial and final states, provides a consistent
probabilistic description, avoiding the standard problems because the width
matrix becomes a composite operator not included in the Hamiltonian. We
consider the dominant-decay channel to two pions, so that one of the Kaon
states with definite lifetime becomes stable. This new approach provides
results for the time dependent decay rates in agreement with those of the WWA.Comment: 10 pages latex, non-trivial observations and clarifications made
compared to previous version, concerning interpretation of results (relevant
parametrization) which leads to agreement of time-dependent rates with those
of WWA. References added. Matches version to appear in Phys. Lett.
An Overview of VPAC Receptors in Rheumatoid Arthritis: Biological Role and Clinical Significance
The axis comprised by the Vasoactive Intestinal Peptide (VIP) and its G protein-coupled receptors (GPCRs), VPAC1, and VPAC2, belong to the B1 family and signal through Gs or Gq proteins. VPAC receptors seem to preferentially interact with Gs in inflammatory cells, rather than Gq, thereby stimulating adenylate cyclase activity. cAMP is able to trigger various downstream pathways, mainly the canonical PKA pathway and the non-canonical cAMP-activated guanine nucleotide exchange factor (EPAC) pathway. Classically, the presence of VPACs has been confined to the plasma membrane; however, VPAC1 location has been described in the nuclear membrane in several cell types such as activated Th cells, where they are also functional. VPAC receptor signaling modulates a number of biological processes by tipping the balance of inflammatory mediators in macrophages and other innate immune cells, modifying the expression of TLRs, and inhibiting MMPs and the expression of adhesion molecules. Receptor signaling also downregulates coagulation factors and acute-phase proteins, promotes Th2 over Th1, stimulates Treg abundance, and finally inhibits a pathogenic Th17 profile. Thus, the VIP axis signaling regulates both the innate and adaptive immune responses in several inflammatory/autoimmune diseases. Rheumatoid arthritis (RA) is a complex autoimmune disease that develops on a substrate of genetically susceptible individuals and under the influence of environmental factors, as well as epigenetic mechanisms. It is a heterogeneous disease with different pathogenic mechanisms and variable clinical forms between patients with the same diagnosis. The knowledge of VIP signaling generated in both animal models and human ex vivo studies can potentially be translated to clinical reality. Most recently, the beneficial effects of nanoparticles of VIP self-associated with sterically stabilized micelles have been reported in a murine model of RA. Another novel research area is beginning to define the receptors as biomarkers in RA, with their expression levels shown to be associated with the activity of the disease and patients-reported impairment. Therefore, VPAC expression together VIP genetic variants could allow patients to be stratified at the beginning of the disease with the purpose of guiding personalized treatment decisions
Unbounded violation of tripartite Bell inequalities
We prove that there are tripartite quantum states (constructed from random
unitaries) that can lead to arbitrarily large violations of Bell inequalities
for dichotomic observables. As a consequence these states can withstand an
arbitrary amount of white noise before they admit a description within a local
hidden variable model. This is in sharp contrast with the bipartite case, where
all violations are bounded by Grothendieck's constant. We will discuss the
possibility of determining the Hilbert space dimension from the obtained
violation and comment on implications for communication complexity theory.
Moreover, we show that the violation obtained from generalized GHZ states is
always bounded so that, in contrast to many other contexts, GHZ states do in
this case not lead to extremal quantum correlations. The results are based on
tools from the theories of operator spaces and tensor norms which we exploit to
prove the existence of bounded but not completely bounded trilinear forms from
commutative C*-algebras.Comment: Substantial changes in the presentation to make the paper more
accessible for a non-specialized reade
Desempeño de la Biomasa Microalgal para la microproducción de Biodiesel a partir de una brecha de potencial energético
It was identified the energy potential (PE) of biodiesel generated by microproducers in Arequipa is 8042.2495 MJ * Kg-1 obtained from 50 gallons of biodiesel (B100), for this reason the present research work aimed at the implications techniques to reach the main gaps that must be overcome in research and development (R & D) to achieve the desired PE in the microalgal biomass as the main source of transesterified oil, the research showed that it is possible to obtain0.82 g / l Biomass microalgal from Chlorella sp. in a Raceway system managing to extract 614.90 g / kg of oil from dry microalgal biomass at your reach 554.32 g / Kg of transesterified oil (Biodiesel-B100), to carry out an investigation as a model for the ALDECO microenterprise. The results were determined for a microproducer looking for an energy potential (PE) of 8042.2495 MJ Kg-1 with a feasible production potential (PPP) of 50 gal / month implying anarea of 2.35 ha under a yield determined by the available biomass potential (PBD) of 820 g / m3 and of generated fuel (PCG) of 28.55 g / m3 in BBM culture medium.Se identificó que el potencial energético (PE) del biodiesel generado por microproductores en Arequipa es de 8042,2495 MJ*Kg-1 obtenido a partir de 50 gal de biodiesel (B100), por tal razón el presente trabajo de investigación tuvo como objetivo determinar las implicancias técnicas para alcanzar las brechas principales que deben superar los esfuerzos en investigación y desarrollo (I+D) para alcanzar el PE deseado utilizando biomasa microalgal como principal fuente deaceite transesterificado, la investigación demostró que es posible obtener 0,82g/L de biomasa microalgal a partir de Chlorella sp. en un sistema Raceway logrando extraer 614,90g/kg de aceite a partir de biomasa microalgal seca alcanzando a generar 554,32 g/Kg de aceite transesterificado (Biodiesel-B100), para realizar la investigación se utilizó como modelo a la microempresa ALDECO. Los resultados determinaron que para un microproductor que busca alcanzar un potencial energético (PE) de 8042,2495 MJ Kg-1 a partir de un potencial de producción factible (PPF) de 50 gal/mes que implica destinar un área de 2,35 ha bajo un rendimiento determinado por el potencial de biomasa disponible (PBD) de 820g/m3 y de combustible generado (PCG) de 28,55 g/m3 en medio de cultivo BBM
Profile of Matrix-Remodeling Proteinases in Osteoarthritis: Impact of Fibronectin
The extracellular matrix (ECM) is a complex and specialized three-dimensional macromolecular network, present in nearly all tissues, that also interacts with cell surface receptors on joint resident cells. Changes in the composition and physical properties of the ECM lead to the development of many diseases, including osteoarthritis (OA). OA is a chronic degenerative rheumatic disease characterized by a progressive loss of synovial joint function as a consequence of the degradation of articular cartilage, also associated with alterations in the synovial membrane and subchondral bone. During OA, ECM-degrading enzymes, including urokinase-type plasminogen activator (uPA), matrix metalloproteinases (MMPs), and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs), cleave ECM components, such as fibronectin (Fn), generating fibronectin fragments (Fn-fs) with catabolic properties. In turn, Fn-fs promote activation of these proteinases, establishing a degradative and inflammatory feedback loop. Thus, the aim of this review is to update the contribution of ECM-degrading proteinases to the physiopathology of OA as well as their modulation by Fn-fs
Time Reversal Violation from the entangled B0-antiB0 system
We discuss the concepts and methodology to implement an experiment probing
directly Time Reversal (T) non-invariance, without any experimental connection
to CP violation, by the exchange of "in" and "out" states. The idea relies on
the B0-antiB0 entanglement and decay time information available at B factories.
The flavor or CP tag of the state of the still living neutral meson by the
first decay of its orthogonal partner overcomes the problem of irreversibility
for unstable systems, which prevents direct tests of T with incoherent particle
states. T violation in the time evolution between the two decays means
experimentally a difference between the intensities for the time-ordered (l^+
X, J/psi K_S) and (J/psi K_L, l^- X) decays, and three other independent
asymmetries. The proposed strategy has been applied to simulated data samples
of similar size and features to those currently available, from which we
estimate the significance of the expected discovery to reach many standard
deviations.Comment: 17 pages, 2 figures, 6 table
A Clinical Approach for the Use of VIP Axis in Inflammatory and Autoimmune Diseases
The neuroendocrine and immune systems are coordinated to maintain the homeostasis of the organism, generating bidirectional communication through shared mediators and receptors. Vasoactive intestinal peptide (VIP) is the paradigm of an endogenous neuropeptide produced by neurons and endocrine and immune cells, involved in the control of both innate and adaptive immune responses. Exogenous administration of VIP exerts therapeutic effects in models of autoimmune/inflammatory diseases mediated by G-protein-coupled receptors (VPAC1 and VPAC2). Currently, there are no curative therapies for inflammatory and autoimmune diseases, and patients present complex diagnostic, therapeutic, and prognostic problems in daily clinical practice due to their heterogeneous nature. This review focuses on the biology of VIP and VIP receptor signaling, as well as its protective effects as an immunomodulatory factor. Recent progress in improving the stability, selectivity, and effectiveness of VIP/receptors analogues and new routes of administration are highlighted, as well as important advances in their use as biomarkers, contributing to their potential application in precision medicine. On the 50th anniversary of VIP’s discovery, this review presents a spectrum of potential clinical benefits applied to inflammatory and autoimmune diseases
The Hilbertian Tensor Norm and Entangled Two-Prover Games
We study tensor norms over Banach spaces and their relations to quantum
information theory, in particular their connection with two-prover games. We
consider a version of the Hilbertian tensor norm and its dual
that allow us to consider games with arbitrary output alphabet
sizes. We establish direct-product theorems and prove a generalized
Grothendieck inequality for these tensor norms. Furthermore, we investigate the
connection between the Hilbertian tensor norm and the set of quantum
probability distributions, and show two applications to quantum information
theory: firstly, we give an alternative proof of the perfect parallel
repetition theorem for entangled XOR games; and secondly, we prove a new upper
bound on the ratio between the entangled and the classical value of two-prover
games.Comment: 33 pages, some of the results have been obtained independently in
arXiv:1007.3043v2, v2: an error in Theorem 4 has been corrected; Section 6
rewritten, v3: completely rewritten in order to improve readability; title
changed; references added; published versio
Short-Term Changes in Respiratory Biomarkers after Swimming in a Chlorinated Pool
36 páginas, 3 figuras, 5 tablas.[BACKGROUND]: Swimming in chlorinated pools involves exposure to disinfection by-products (DBPs) and has been associated with impaired respiratory health.[OBJECTIVES]: We evaluated short-term changes in several respiratory biomarkers to explore mechanisms of potential lung damage related to swimming pool exposure.[METHODS]: We measured lung function and biomarkers of airway inflammation (fractional exhaled nitric oxide –FeNO- and 8 cytokines and 1 growth factor (VEGF) in exhaled breath condensate), oxidative stress (8-isoprostane in exhaled breath condensate), and lung permeability (surfactant protein D -SPD- and the Clara cell secretory protein -CC16- in serum) in 48 healthy non-smoking adults before and after swimming for 40 min in a chlorinated indoor swimming pool. We measured trihalomethanes in exhaled breath as a marker of individual exposure to DBPs. Energy expenditure during swimming, atopy and CC16 genotype (rs3741240) was also determined.[RESULTS]: Median serum CC16 levels increased from 6.01 to 6.21 μg/L (average increase 3.3%, paired Wilcoxon test p = 0.03), regardless of atopic status and CC16 genotype. This increase was explained both by energy expenditure and different markers of DBP exposure in multivariate models. FeNO was unchanged overall but tended to decrease among atopics. We found no significant changes in lung function, SP-D, 8-isoprostane, 8 cytokines and VEGF.[CONCLUSIONS]: A slight increase in serum CC16, a marker of lung epithelium permeability, was detected in healthy adults after swimming in an indoor chlorinated pool. Exercise and DBP exposure explained this association, without involving inflammatory mechanisms. Further research is needed to confirm the results, establish the clinical relevance of short-term serum CC16 changes, and evaluate the long-term health impacts.Work funded by the
projects SAF2005-07643-C03-01; CP06/00341; CP01/3058; SAF2007-62719,
FISCP06/00341 and FI06/00651.Peer reviewe
Analyzing multitarget activity landscapes using protein-ligand interaction fingerprints: interaction cliffs.
This is the original submitted version, before peer review. The final peer-reviewed version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/ci500721x.Activity landscape modeling is mostly a descriptive technique that allows rationalizing continuous and discontinuous SARs. Nevertheless, the interpretation of some landscape features, especially of activity cliffs, is not straightforward. As the nature of activity cliffs depends on the ligand and the target, information regarding both should be included in the analysis. A specific way to include this information is using protein-ligand interaction fingerprints (IFPs). In this paper we report the activity landscape modeling of 507 ligand-kinase complexes (from the KLIFS database) including IFP, which facilitates the analysis and interpretation of activity cliffs. Here we introduce the structure-activity-interaction similarity (SAIS) maps that incorporate information on ligand-target contact similarity. We also introduce the concept of interaction cliffs defined as ligand-target complexes with high structural and interaction similarity but have a large potency difference of the ligands. Moreover, the information retrieved regarding the specific interaction allowed the identification of activity cliff hot spots, which help to rationalize activity cliffs from the target point of view. In general, the information provided by IFPs provides a structure-based understanding of some activity landscape features. This paper shows examples of analyses that can be carried out when IFPs are added to the activity landscape model.M-L is very
grateful to CONACyT (No. 217442/312933) and the Cambridge Overseas Trust for funding. AB
thanks Unilever for funding and the European Research Council for a Starting Grant (ERC-2013-
StG-336159 MIXTURE). J.L.M-F. is grateful to the School of Chemistry, Department of
Pharmacy of the National Autonomous University of Mexico (UNAM) for support. This work
was supported by a scholarship from the Secretariat of Public Education and the Mexican
government
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