The thermodynamics of creating correlations: Limitations and optimal protocols

We establish a rigorous connection between fundamental resource theories at the quantum scale. Correlations and entanglement constitute indispensable resources for numerous quantum information tasks. However, their establishment comes at the cost of energy, the resource of thermodynamics, and is limited by the initial entropy. Here, the optimal conversion of energy into correlations is investigated. Assuming the presence of a thermal bath, we establish general bounds for arbitrary systems and construct a protocol saturating them. The amount of correlations, quantified by the mutual information, can increase at most linearly with the available energy, and we determine where the linear regime breaks down. We further consider the generation of genuine quantum correlations, focusing on the fundamental constituents of our universe: fermions and bosons. For fermionic modes, we find the optimal entangling protocol. For bosonic modes, we show that while Gaussian operations can be outperformed in creating entanglement, their performance is optimal for high energies.Comment: 12 pages, 6 figure

Markovian master equations for quantum thermal machines: local vs global approach

The study of quantum thermal machines, and more generally of open quantum systems, often relies on master equations. Two approaches are mainly followed. On the one hand, there is the widely used, but often criticized, local approach, where machine sub-systems locally couple to thermal baths. On the other hand, in the more established global approach, thermal baths couple to global degrees of freedom of the machine. There has been debate as to which of these two conceptually different approaches should be used in situations out of thermal equilibrium. Here we compare the local and global approaches against an exact solution for a particular class of thermal machines. We consider thermodynamically relevant observables, such as heat currents, as well as the quantum state of the machine. Our results show that the use of a local master equation is generally well justified. In particular, for weak inter-system coupling, the local approach agrees with the exact solution, whereas the global approach fails for non-equilibrium situations. For intermediate coupling, the local and the global approach both agree with the exact solution and for strong coupling, the global approach is preferable. These results are backed by detailed derivations of the regimes of validity for the respective approaches.Comment: Published version. See also the related work by J. Onam Gonzalez et al. arXiv:1707.0922

Klebsiella pneumoniae triggers a cytotoxic effect on airway epithelial cells

<p>Abstract</p> <p>Background</p> <p><it>Klebsiella pneumoniae </it>is a capsulated Gram negative bacterial pathogen and a frequent cause of nosocomial infections. Despite its clinical relevance, little is known about the features of the interaction between <it>K. pneumoniae </it>and lung epithelial cells on a cellular level, neither about the role of capsule polysaccharide, one of its best characterised virulence factors, in this interaction.</p> <p>Results</p> <p>The interaction between <it>Klebsiella pneumoniae </it>and cultured airway epithelial cells was analysed. <it>K. pneumoniae </it>infection triggered cytotoxicity, evident by cell rounding and detachment from the substrate. This effect required the presence of live bacteria and of capsule polysaccharide, since it was observed with isolates expressing different amounts of capsule and/or different serotypes but not with non-capsulated bacteria. Cytotoxicity was analysed by lactate dehydrogenase and formazan measurements, ethidium bromide uptake and analysis of DNA integrity, obtaining consistent and complementary results. Moreover, cytotoxicity of non-capsulated strains was restored by addition of purified capsule during infection. While a non-capsulated strain was avirulent in a mouse infection model, capsulated <it>K. pneumoniae </it>isolates displayed different degrees of virulence.</p> <p>Conclusion</p> <p>Our observations allocate a novel role to <it>K. pneumoniae </it>capsule in promotion of cytotoxicity. Although this effect is likely to be associated with virulence, strains expressing different capsule levels were not equally virulent. This fact suggests the existence of other bacterial requirements for virulence, together with capsule polysaccharide.</p

Enabling automatic just-in-time evaluation of in-class discussions in on-line collaborative learning practices

Learning by discussion when applied to on-line collaborative learning settings can provide significant benefits for students in education in general. Indeed, the discussion process plays an important social task in collaborative learning practices. Participants can discuss about the activity being performed, collaborate with each other through the exchange of ideas that may arise, propose new resolution mechanisms, justify and refine their own contributions, and as a result, acquire new knowledge. Considering these benefits, current educational organizations incorporate on-line discussions into web-based courses as part of the very rationale of their pedagogical models. However, in-class collaborative assignments are usually greatly participated and contributed, which makes the monitoring and assessment tasks by tutors and moderators time-consuming, tedious and error-prone. Specially hard if not impossible by human tutors is to manually deal with the sequences of hundreds of contributions making up the discussion threads and the relations between these contributions. Consequently, tutoring tasks during on-line discussions usually restrict to offer evaluation results of the contributing effort and quality after the collaborative learning activity takes place and thus neglect the essential issue of constantly considering the process of knowledge building while it is still being performed. In this paper, we propose a multidimensional model based on data analysis from online collaborative discussion interactions that provides a first step towards an automatic evaluation in just-in-time fashion. The context of this study is a real on-line discussion experience that took place at the Open University of Catalonia.Peer ReviewedPostprint (published version

Treatments to Optimize Dental Implant Surface Topography and Enhance Cell Bioactivity

Osseointegration is a biological process in which histological, surgical, infectious factors, biomechanical load, and the choice of biomaterials all play important roles. In the case of dental implants, the success of this process is also influenced by the design, composition, and properties of the implant surface, which may stimulate cell bioactivity and promote osteoblast adhesion. Currently, the raw materials most frequently used in the manufacture of dental implants are titanium, its alloys, and certain ceramic materials such as zirconia. Multiple macroscopic designs incorporating various diameters, lengths, shapes, and types of screw offer different options for specific clinical situations. The characteristics of implant surfaces have aroused great interest, due to their importance in osseointegration. The different methods used to modify surface properties are classified as additive (i.e., impregnation and coating) or subtractive (i.e., physical, mechanical and chemical methods). The surface characteristics of dental implants also have a significant influence on peri-implant microbiota

The geological and paleontological heritage of Manresa municipality (Catalonia, Spain)

A preliminary inventory of 14 points of geological interest has been carried out in the Manresa municipality (Barcelona, Catalonia, Spain). All the rocks within this area belong to the sedimentary infill of the Ebro basin that took place during the Eocene. The municipality is relatively small and contains a relevant heritage of of sedimentology, paleontology and, to a lesser extent, geomorphologic and structural. The proposal of points of geological interests includes several relatively small outcrops that display: geomorphology (a rock bridge), two sedimentary structures (a slump and cross bedding), clastic sedimentology, a reef, faults, joints, and two fluvial 394 terraces. Another point combines geomorphology, sedimentology and mineralogy. Finally, the relatively larger Malbalç geozone is the most remarkable point and includes paleontology, sedimentology, geomorphology and ancient quarrying. In 1926 this zouctural.ne was visited as part of the XIV International Geological Congress. The whole set of points of geological interest are ideal to teach geology for the divulgative to academic level.Peer ReviewedPostprint (published version

Dissection of Host Cell Signal Transduction during Acinetobacter baumannii – Triggered Inflammatory Response

Infected airway epithelial cells up-regulate the expression of chemokines, chiefly IL-8, and antimicrobial molecules including β-defensins (BD). Acinetobacter baumannii is a cause of hospital-acquired pneumonia. We examined whether A. baumannii induced the expressions of IL-8 and BD2 by airway epithelial cells and the receptors implicated in bacterial detection. A549 and human primary airway cells released IL-8 upon infection. A. baumannii-infected cells also increased the expression of BD2 which killed A. baummannii strains. IL-8 induction was via NF-κB and mitogen-activated kinases p38 and p44/42-dependent pathways. A. baumannii engaged Toll-like receptor (TLR) 2 and TLR4 pathways and A549 cells could use soluble CD14 as TLRs co-receptor. A. baumannii lipopolysaccharide stimulated IL-8 release by A549 cells and sCD14 facilitated the recognition of the lipopolysaccharide. Mass spectrometry analysis revealed that A. baumannii lipid A structure matches those with endotoxic potential. These results demonstrate that airway epithelial cells produce mediators important for A. baumannii clearance

Papel del sistema de fosforilación oxidativa en la diferenciación a adipocito

La alta prevalencia en la sociedad actual de la obesidad y sus patologías asociadas genera un foco de interés sobre las investigaciones en torno al tejido adiposo. Este interés se ha visto incrementado con los recientes descubrimientos acerca de la influencia de determinados factores ambientales en la dinámica de dicho tejido, que pueden incluso desembocar en la aparición de fenotipos patológicos. El punto de mira recae, por tanto, en las células que constituyen el tejido implicado: los adipocitos. Estas células alcanzan su fenotipo a través de un conjunto de cambios morfológicos y de expresión génica que constituyen la diferenciación adipogénica. Dada la implicación en la diferenciación celular del sistema de fosforilación oxidativa (OXPHOS), una ruta metabólica energética de las mitocondrias, se ha decidido estudiar su papel en este mecanismo. Para ello, se sometió a células hASC a las condiciones de diferenciación en ausencia y en presencia de un factor ambiental concreto: diferentes xenobioticos inhibidores del sistema OXPHOS. Los compuestos elegidos fueron rotenona (10 nM), antimicina A (10 nM) y oligomicina (16 nM), y cada uno se ensayó por separado. Los resultados obtenidos muestran que impedir el correcto funcionamiento del sistema OXPHOS durante el proceso de diferenciación adipogénica repercute en ella, alterándola respecto al proceso natural

Markovian master equations for quantum thermal machines: local versus global approach

The study of quantum thermal machines, and more generally of open quantum systems, often relies on master equations. Two approaches are mainly followed. On the one hand, there is the widely used, but often criticized, local approach, where machine sub-systems locally couple to thermal baths. On the other hand, in the more established global approach, thermal baths couple to global degrees of freedom of the machine. There has been debate as to which of these two conceptually different approaches should be used in situations out of thermal equilibrium. Here we compare the local and global approaches against an exact solution for a particular class of thermal machines. We consider thermodynamically relevant observables, such as heat currents, as well as the quantum state of the machine. Our results show that the use of a local master equation is generally well justified. In particular, for weak inter-system coupling, the local approach agrees with the exact solution, whereas the global approach fails for non-equilibrium situations. For intermediate coupling, the local and the global approach both agree with the exact solution and for strong coupling, the global approach is preferable. These results are backed by detailed derivations of the regimes of validity for the respective approaches