46 research outputs found

    No-go theorems for photon state transformations in quantum linear optics

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    We give a necessary condition for photon state transformations in linear optical setups preserving the total number of photons. From an analysis of the algebra describing the quantum evolution, we find a conserved quantity that appears in all allowed optical transformations. We comment some examples and numerical applications, with example code, and give three general no-go results. These include (i) the impossibility of deterministic transformations which redistribute the photons from one to two different modes, (ii) a proof that it is impossible to generate a perfect Bell state in heralded schemes with a separable input for any number of ancillary photons and modes and a fixed herald and (iii) a restriction for the conversion between different types of entanglement (converting GHZ to W states).Comment: 18 pages. Comments welcome

    Screening of autochthonous lactic acid bacteria strains from artisanal soft cheese: probiotic characteristics and prebiotic metabolism

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    Today's growing interest in functional foods is due to their positive impacts on human health. The aim of this study was to evaluate the probiotic properties and prebiotic metabolism of autochthonous lactic acid bacteria from artisanal Serpa cheese. Twenty strains presented better tolerance to stress conditions found in the gastrointestinal tract, highlighting Lactobacillus brevis C1Lb21 for its adequate auto-aggregating ability and significantly higher hydrophobicity. However, eight strains were discarded for their antibiotic resistance and biogenic amine production. Finally, prebiotic fermentation study showed that lactulose supported better growth of lactobacilli and induced the production of short-chain fatty acids (SCFA). During lactulose fermentation, Lb. pentosus G4Lb7 produced statistically more SCFA, and Lb. plantarum G1Lb5 lactic acid. Thus, Lb. brevis C1Lb21, Lb. plantarum G1Lb5 and Lb. pentosus G4Lb7 are promising probiotic candidates, and in combination with lactulose could be used for developing a symbiotic cheese

    Microtubule stabilization reduces amyloid pathology and improves synaptic/memory deficits in APP/PS1 mice

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    Aims: Cognitive decline in Alzheimer's disease (AD) is highly related to synaptic/neuronal loss. Tau hyperphosphorylation destabilizes microtubules leading to axonal transport failure and generation of dystrophic neurites, thus contributing to synaptic dysfunction. The effect of microtubule stabilization on amyloid-beta pathology has not been assessed in vivo yet. This study evaluated the effect of the microtubule-stabilizing agent, Epothilone D (EpoD) in the pathology of an amyloidogenic mouse model. Methods: APP751SL/PS1M146L mice (3-month-old) were treated weekly with intraperitoneal injections of EpoD (2 mg/kg) or vehicle for 3 months. For memory performance, animals were tested on the objectrecognition, Y-maze and Morris water maze. Hippocampal proteinopathies were quantified by image analysis after immunostaining. Somatostatin (SOM)-numerical density was calculated by stereology. APPswe-N2a cells were treated with EpoD 100nM for 12/24 hours. Protein levels were analysed by Western/dot-blot. Results: EpoD-treated mice improved their performance of cognitive tests, while hippocampal phospho-tau and Ab (especially oligomers) accumulation decreased, together with synaptic/neuritic pathology. Remarkably, EpoD exerted a neuroprotective effect on SOM-interneurons, a highly AD-vulnerable GABAergic subpopulation. Conclusions: EpoD improved microtubule dynamics and axonal transport in an AD-like context, reducing tau and Ab accumulation and promoting neuronal and cognitive protection, underlining the cross-talk between cytoskeleton pathology and proteinopathy. Therefore, microtubule-stabilizing drugs could be candidates for slowing AD at both tau and Ab pathologies.Supported by PI18/01557 (to AG) and PI18/01556 (to JV) grants from ISCiii of Spain, co-financed by FEDER funds (European Union), CIBERNED collaborative grant (to AG and JV), and by PPIT.UMA.B1.2017/26 grant (to RSV). Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Bioprospecting reveals class III ω-transaminases converting bulky ketones and environmentally relevant polyamines

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    Amination of bulky ketones, particularly in (R) configuration, is an attractive chemical conversion; however, known ω-transaminases (ω-TAs) show insufficient levels of performance. By applying two screening methods, we discovered 10 amine transaminases from the class III ω-TA family that were 38% to 76% identical to homologues. We present examples of such enzymes preferring bulky ketones over keto acids and aldehydes with stringent (S) selectivity. We also report representatives from the class III ω-TAs capable of converting (R) and (S) amines and bulky ketones and one that can convert amines with longer alkyl substituents. The preference for bulky ketones was associated with the presence of a hairpin region proximal to the conserved Arg414 and residues conforming and close to it. The outward orientation of Arg414 additionally favored the conversion of (R) amines. This configuration was also found to favor the utilization of putrescine as an amine donor, so that class III ω-TAs with Arg414 in outward orientation may participate in vivo in the catabolism of putrescine. The positioning of the conserved Ser231 also contributes to the preference for amines with longer alkyl substituents. Optimal temperatures for activity ranged from 45 to 65°C, and a few enzymes retained ≥50% of their activity in water-soluble solvents (up to 50% [vol/vol]). Hence, our results will pave the way to design, in the future, new class III ω-TAs converting bulky ketones and (R) amines for the production of high-value products and to screen for those converting putrescine

    Advanced Technologies for Oral Controlled Release: Cyclodextrins for oral controlled release

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    Cyclodextrins (CDs) are used in oral pharmaceutical formulations, by means of inclusion complexes formation, with the following advantages for the drugs: (1) solubility, dissolution rate, stability and bioavailability enhancement; (2) to modify the drug release site and/or time profile; and (3) to reduce or prevent gastrointestinal side effects and unpleasant smell or taste, to prevent drug-drug or drug-additive interactions, or even to convert oil and liquid drugs into microcrystalline or amorphous powders. A more recent trend focuses on the use of CDs as nanocarriers, a strategy that aims to design versatile delivery systems that can encapsulate drugs with better physicochemical properties for oral delivery. Thus, the aim of this work was to review the applications of the CDs and their hydrophilic derivatives on the solubility enhancement of poorly water soluble drugs in order to increase their dissolution rate and get immediate release, as well as their ability to control (to prolong or to delay) the release of drugs from solid dosage forms, either as complexes with the hydrophilic (e.g. as osmotic pumps) and/ or hydrophobic CDs. New controlled delivery systems based on nanotechonology carriers (nanoparticles and conjugates) have also been reviewed

    Mucoidy, Quorum Sensing, Mismatch Repair and Antibiotic Resistance in Pseudomonas aeruginosa from Cystic Fibrosis Chronic Airways Infections

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    Survival of Pseudomonas aeruginosa in cystic fibrosis (CF) chronic infections is based on a genetic adaptation process consisting of mutations in specific genes, which can produce advantageous phenotypic switches and ensure its persistence in the lung. Among these, mutations inactivating the regulators MucA (alginate biosynthesis), LasR (quorum sensing) and MexZ (multidrug-efflux pump MexXY) are the most frequently observed, with those inactivating the DNA mismatch repair system (MRS) being also highly prevalent in P. aeruginosa CF isolates, leading to hypermutator phenotypes that could contribute to this adaptive mutagenesis by virtue of an increased mutation rate. Here, we characterized the mutations found in the mucA, lasR, mexZ and MRS genes in P. aeruginosa isolates obtained from Argentinean CF patients, and analyzed the potential association of mucA, lasR and mexZ mutagenesis with MRS-deficiency and antibiotic resistance. Thus, 38 isolates from 26 chronically infected CF patients were characterized for their phenotypic traits, PFGE genotypic patterns, mutations in the mucA, lasR, mexZ, mutS and mutL gene coding sequences and antibiotic resistance profiles. The most frequently mutated gene was mexZ (79%), followed by mucA (63%) and lasR (39%) as well as a high prevalence (42%) of hypermutators being observed due to loss-of-function mutations in mutL (60%) followed by mutS (40%). Interestingly, mutational spectra were particular to each gene, suggesting that several mechanisms are responsible for mutations during chronic infection. However, no link could be established between hypermutability and mutagenesis in mucA, lasR and mexZ, indicating that MRS-deficiency was not involved in the acquisition of these mutations. Finally, although inactivation of mucA, lasR and mexZ has been previously shown to confer resistance/tolerance to antibiotics, only mutations in MRS genes could be related to an antibiotic resistance increase. These results help to unravel the mutational dynamics that lead to the adaptation of P. aeruginosa to the CF lung

    The impact of Industry 4.0 on the relationship between TPM and maintenance performance

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    Purpose In this paper, the authors examine the impact of Industry 4.0 (I4.0) technologies on the relationship between total productive maintenance (TPM) practices and maintenance performance. Design/methodology/approach Data collection was carried out through a multinational survey with 318 respondents from different manufacturing companies located in 15 countries. Multivariate data techniques were applied to analyze the collected data. Diffusion of innovations theory (DIT) was the adopted theoretical lens for our research. Findings The authors’ findings indicate that I4.0 technologies that aim to process information to support decision-making and action-taking directly affect maintenance performance. Technologies oriented to sensing and communicating data among machines, people, and products seem to moderate the relationship between TPM practices and maintenance performance. However, the extent of such moderation varies according to the practices involved, sometimes leading to negative effects. Originality/value With the advances of I4.0, there is an expectation that several maintenance practices and performance may be affected. Our study provides empirical evidence of these relationships, unveiling the role of I4.0 for maintenance performance improvement

    Social Experiments in the Mesoscale: Humans Playing a Spatial Prisoner's Dilemma

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    Background: The evolutionary origin of cooperation among unrelated individuals remains a key unsolved issue across several disciplines. Prominent among the several mechanisms proposed to explain how cooperation can emerge is the existence of a population structure that determines the interactions among individuals. Many models have explored analytically and by simulation the effects of such a structure, particularly in the framework of the Prisoner’s Dilemma, but the results of these models largely depend on details such as the type of spatial structure or the evolutionary dynamics. Therefore, experimental work suitably designed to address this question is needed to probe these issues. Methods and Findings: We have designed an experiment to test the emergence of cooperation when humans play Prisoner’s Dilemma on a network whose size is comparable to that of simulations. We find that the cooperation level declines to an asymptotic state with low but nonzero cooperation. Regarding players ’ behavior, we observe that the population is heterogeneous, consisting of a high percentage of defectors, a smaller one of cooperators, and a large group that shares features of the conditional cooperators of public goods games. We propose an agent-based model based on the coexistence of these different strategies that is in good agreement with all the experimental observations. Conclusions: In our large experimental setup, cooperation was not promoted by the existence of a lattice beyond a residual level (around 20%) typical of public goods experiments. Our findings also indicate that both heterogeneity and a ‘‘moody’

    Individual strategy update and emergence of cooperation in social networks

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    In this paper, we critically study whether social networks can explain the emergence of cooperative behavior. We carry out an extensive simulation program in which we study the most representative social dilemmas. For the Prisoner’s Dilemma, it turns out that the emergence of cooperation is very dependent on the micro-dynamics. On the other hand, network clustering mostly facilitates global cooperation in the Stag Hunt game, whereas degree heterogeneity promotes cooperation in Snowdrift dilemmas. Thus, social networks do not promote cooperation in general, because the macrooutcome is not robust under change of dynamics. Therefore, having specific applications of interest in mind is crucial to include the appropriate microdetails in a good model.This work has been supported by Ministerio de Ciencia e Innovación (Spain) through grant MOSAICO, and by Comunidad de Madrid (Spain) through grant MODELICO-CM.Publicad

    4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

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    Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas
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