Global Quantum Thermometry.

A paradigm shift in quantum thermometry is proposed. To date, thermometry has relied on local estimation, which is useful to reduce statistical fluctuations once the temperature is very well known. In order to estimate temperatures in cases where few measurement data or no substantial prior knowledge are available, we build instead a method for global quantum thermometry. Based on scaling arguments, a mean logarithmic error is shown here to be the correct figure of merit for thermometry. Its full minimization provides an operational and optimal rule to postprocess measurements into a temperature reading, and it establishes a global precision limit. We apply these results to the simulated outcomes of measurements on a spin gas, finding that the local approach can lead to biased temperature estimates in cases where the global estimator converges to the true temperature. The global framework thus enables a reliable approach to data analysis in thermometry experiments.

Pushing the limits of the reaction-coordinate mapping.

The reaction-coordinate mapping is a useful technique to study complex quantum dissipative dynamics into structured environments. In essence, it aims to mimic the original problem by means of an "augmented system," which includes a suitably chosen collective environmental coordinate-the "reaction coordinate." This composite then couples to a simpler "residual reservoir" with short-lived correlations. If, in addition, the residual coupling is weak, a simple quantum master equation can be rigorously applied to the augmented system, and the solution of the original problem just follows from tracing out the reaction coordinate. But, what if the residual dissipation is strong? Here, we consider an exactly solvable model for heat transport-a two-node linear "quantum wire" connecting two baths at different temperatures. We allow for a structured spectral density at the interface with one of the reservoirs and perform the reaction-coordinate mapping, writing a perturbative master equation for the augmented system. We find that (a) strikingly, the stationary state of the original problem can be reproduced accurately by a weak-coupling treatment even when the residual dissipation on the augmented system is very strong, (b) the agreement holds throughout the entire dynamics under large residual dissipation in the overdamped regime; and (c) such a master equation can grossly overestimate the stationary heat current across the wire, even when its nonequilibrium steady state is captured faithfully. These observations can be crucial when using the reaction-coordinate mapping to study the largely unexplored strong-coupling regime in quantum thermodynamics.

Classical emulation of quantum-coherent thermal machines.

The performance enhancements observed in various models of continuous quantum thermal machines have been linked to the buildup of coherences in a preferred basis. But is this connection always an evidence of "quantum-thermodynamic supremacy"? By force of example, we show that this is not the case. In particular, we compare a power-driven three-level continuous quantum refrigerator with a four-level combined cycle, partly driven by power and partly by heat. We focus on the weak driving regime and find the four-level model to be superior since it can operate in parameter regimes in which the three-level model cannot and it may exhibit a larger cooling rate and, simultaneously, a better coefficient of performance. Furthermore, we find that the improvement in the cooling rate matches the increase in the stationary quantum coherences exactly. Crucially, though, we also show that the thermodynamic variables for both models follow from a classical representation based on graph theory. This implies that we can build incoherent stochastic-thermodynamic models with the same steady-state operation or, equivalently, that both coherent refrigerators can be emulated classically. More generally, we prove this for any N-level weakly driven device with a "cyclic" pattern of transitions. Therefore, even if coherence is present in a specific quantum thermal machine, it is often not essential to replicate the underlying energy conversion process.

Using Polarons for sub-nK Quantum Nondemolition Thermometry in a Bose-Einstein Condensate.

We introduce a novel minimally disturbing method for sub-nK thermometry in a Bose-Einstein condensate (BEC). Our technique is based on the Bose polaron model; namely, an impurity embedded in the BEC acts as the thermometer. We propose to detect temperature fluctuations from measurements of the position and momentum of the impurity. Crucially, these cause minimal backaction on the BEC and hence, realize a nondemolition temperature measurement. Following the paradigm of the emerging field of quantum thermometry, we combine tools from quantum parameter estimation and the theory of open quantum systems to solve the problem in full generality. We thus avoid any simplification, such as demanding thermalization of the impurity atoms, or imposing weak dissipative interactions with the BEC. Our method is illustrated with realistic experimental parameters common in many labs, thus showing that it can compete with state-of-the-art destructive techniques, even when the estimates are built from the outcomes of accessible (suboptimal) quadrature measurements.

Extracellular vesicles are associated with the systemic inflammation of patients with seropositive rheumatoid arthritis.

Patients with rheumatoid arthritis (RA) and autoantibodies, such as rheumatoid factor and those against cyclic citrullinated peptides, are designated as seropositive and have a more severe disease with worse prognosis than seronegative RA patients. Understanding the factors that participate in systemic inflammation, in addition to articular commitment, would allow better treatment approaches for prevention of RA comorbidities and disease reactivation. We evaluated whether monocyte subsets and extracellular vesicles (EVs) could contribute to this phenomenon. Seropositive patients had higher levels of proinflammatory cytokines than those of seronegative patients and healthy controls (HCs); however, this systemic inflammatory profile was unrelated to disease activity. High frequencies of circulating EVs positive for IgG, IgM, CD41a, and citrulline, together with altered counts and receptor expression of intermediate monocytes, were associated with systemic inflammation in seropositive patients; these alterations were not observed in seronegative patients, which seem to be more similar to HCs. Additionally, the EVs from seropositive patients were able to activate mononuclear phagocytes in vitro, and induced proinflammatory cytokines that were comparable to the inflammatory response observed at the systemic level in seropositive RA patients; therefore, all of these factors may contribute to the greater disease severity that has been described in these patients.

The Spontaneous Control of HIV Replication is Characterized by Decreased Pathological Changes in the Gut-associated Lymphoid Tissue.

BACKGROUND: HIV infection induces alterations in the gut-associated lymphoid tissue (GALT) that constitutes the most important site for viral replication due to the extensive presence of effector memory T-cells. In the case of HIV-controllers, several studies have reported fewer peripheral alterations and conserved immune responses that correlate with viral control; however, the histopathological characterization of GALT in those patients is still missing. In this study, we evaluated pathological alterations in GALT, trying to associate them with clinical parameters of HIV infected patients with or without evidence of viral control. METHODS: This study included eight HIV-controllers (antiretroviral treatment-naïve patients, with viral loads below 2.000 copies/mL for at least 1 year); 14 Noncontrollers (antiretroviral treatmentnaïve patients, with viral loads > 2.000 copies/mL and CD4+ T cells count > 250 cells/µL), and 12 uninfected donors. Biopsy fragments were obtained by rectosigmoidoscopy and stained with hematoxylin and eosin, silver methenamine, Ziehl Neelsen, and modified Ziehl Neelsen. RESULTS: Histopathological findings in HIV-controllers were similar to those observed in the uninfected group. In contrast, noncontrollers exhibited several alterations including condyloma acuminate, squamous metaplasia and acute colitis. These alterations were associated with disease progression. CONCLUSION: HIV-controllers exhibit lower pathological alterations in the gut tissue, associated with higher CD4 T cell count, and lower viral load.

Data in support of dyslipidemia-associated alterations in B cell subpopulations frequency and phenotype during experimental atherosclerosis.

Cardiovascular diseases are the most common cause of death in the world, atherosclerosis being its main underlying disease. Information about the role of B cells during atherosclerotic process is scarce, but both proatherogenic and atheroprotective properties have been described in the immunopathology of this disease. Frequency and phenotype of B cell subpopulations were studied in wild type and apolipoprotein-E-deficient (apoE (-/-) ) mice fed or not with high-fat diet (HFD), by flow cytometry. Here, we provide the information about the materials, methods, analysis and additional information related to our study published in Atherosclerosis (DOI: 10.1016/j.atherosclerosis.2015.12.022, article reference: ATH14410) [1]. The data contained in this article shows and supports that mice with advanced atherosclerosis have a variety of alterations in frequency and phenotype of B cell subsets, most of which associated with dyslipidemia.

Dyslipidemia-associated alterations in B cell subpopulation frequency and phenotype during experimental atherosclerosis.

Lymphocytes, the cellular effectors of adaptive immunity, are involved in the chronic inflammatory process known as atherosclerosis. Proatherogenic and atheroprotective properties have been ascribed to B cells. However, information regarding the role of B cells during atherosclerosis is scarce. Both the frequency and the phenotype of B cell subpopulations were studied by flow cytometry in wild type and apolipoprotein-E-deficient (apoE(-/-)) mice fed a high-fat (HFD) or control diet. Whereas the proportion of follicular cells was decreased, transitional 1-like cells were increased in mice with advanced atherosclerotic lesions (apoE(-/-) HFD). B cells in atherosclerotic mice were more activated, indicated by their higher surface expression of CD80, CD86, CD40 and CD95 and increased serum IgG1 levels. In the aorta, a decreased frequency of B cells was observed in mice with advanced atherosclerosis. Low expression of CD19 was observed on B cells from the spleen, aorta and lymph nodes of apoE(-/-) HFD mice. This alteration correlated with serum levels of IgG1 and cholesterol. A reduction in CD19 expression was induced in splenic cells from young apoE(-/-) mice cultured with lipemic serum. These results show that mice with advanced atherosclerosis display a variety of alterations in the frequency and phenotype of B lymphocytes, most of which are associated with dyslipidemia.

Particular activation phenotype of T cells expressing HLA-DR but not CD38 in GALT from HIV-controllers is associated with immune regulation and delayed progression to AIDS.

The spontaneous control of HIV replication in HIV-controllers underlines the importance of these subjects for exploring factors related to delayed progression. Several studies have revealed fewer immune alterations and effector mechanisms related to viral control, mainly in peripheral blood, in these individuals compared to normal progressors. However, immune characterization of gut-associated lymphoid tissue (GALT), the major target of infection, has not been thoroughly explored in these subjects. We evaluated the following parameters in GALT samples from 11 HIV-controllers and 15 HIV-progressors: (i) frequency and activation phenotype of T cells; (ii) expression of transcription factors associated with immune response profiles; and (iii) frequency of apoptotic cells. Interestingly, HIV-controllers exhibited a particular activation phenotype, with predominance of T cells expressing HLA-DR but not CD38 in GALT. This phenotype, previously associated with better control of infection, was correlated with low viral load and higher CD4(+) T cell count. Furthermore, a positive correlation of this activation phenotype with higher expression of Foxp3 and RORγT transcription factors suggested a key role for Treg and Th17 cells in the control of the immune activation and in the maintenance of gut mucosal integrity. Although we evaluated apoptosis by measuring expression of cleaved caspase-3 in GALT, we did not find differences between HIV-controllers and HIV-progressors. Taken together, our findings suggest that predominance of HLA-DR(+) T cells, along with lower immune activation and higher expression of transcription factors required for the development of Treg and Th17 cells, is associated with better viral control and delayed progression to AIDS.

Internal dissipation and heat leaks in quantum thermodynamic cycles.

The direction of the steady-state heat currents across a generic quantum system connected to multiple baths may be engineered to realize virtually any thermodynamic cycle. In spite of their versatility, such continuous energy-conversion systems are generally unable to operate at maximum efficiency due to non-negligible sources of irreversible entropy production. In this paper we introduce a minimal model of irreversible absorption chiller. We identify and characterize the different mechanisms responsible for its irreversibility, namely heat leaks and internal dissipation, and gauge their relative impact in the overall cooling performance. We also propose reservoir engineering techniques to minimize these detrimental effects. Finally, by looking into a known three-qubit embodiment of the absorption cooling cycle, we illustrate how our simple model may help to pinpoint the different sources of irreversibility naturally arising in more complex practical heat devices.

Individual Quantum Probes for Optimal Thermometry.

The unknown temperature of a sample can be estimated with minimal disturbance by putting it in thermal contact with an individual quantum probe. If the interaction time is sufficiently long so that the probe thermalizes, the temperature can be read-out directly from its steady state. Here we prove that the optimal quantum probe, acting as a thermometer with maximal thermal sensitivity, is an effective two-level atom with a maximally degenerate excited state. When the total interaction time is insufficient to produce full thermalization, we optimize the estimation protocol by breaking it down into sequential stages of probe preparation, thermal contact, and measurement. We observe that frequently interrogated probes initialized in the ground state achieve the best performance. For both fully and partly thermalized thermometers, the sensitivity grows significantly with the number of levels, though optimization over their energy spectrum remains always crucial.

Spontaneous HIV Controllers Exhibit Preserved Immune Parameters in Peripheral Blood and Gastrointestinal Mucosa.

BACKGROUND: HIV infection induces several gradual alterations on the peripheral and mucosal immune systems, with different magnitudes between infected individuals. In this regard, spontaneous HIV controllers exhibit either low or undetectable viral loads in the absence of treatment along with decreased immune alterations compared to HIV progressors. Yet, it is unknown how similar immune peripheral and mucosal parameters are when comparing HIV controllers to uninfected individuals. METHODS: We evaluated a cohort of 11 HIV controllers who were compared to 20 seronegative donors. Peripheral blood (PB) and gut associated lymphoid tissue (GALT) samples were obtained to analyze the following: 1) the frequency and phenotype of immune cells by flow cytometry; 2) the expression of apoptotic molecules by immunohistochemistry; 3) the expression of transcriptional factors associated with T cell profiles by real time PCR; and 4) the serum level of microbial translocation by an enzymatic reaction. RESULTS: We found that HIV controllers have a conserved frequency of most immune cell populations in PB and GALT, but a reduced percentage of CD4 T cells. The immune activation levels were similar in both groups of individuals, as well as the expression of cleaved caspase-3, transcriptional factors, and the level of microbial translocation. Interestingly, the frequency of CD8 T cells expressing HLA-DR but not CD38, previously associated with high effector functions, were preserved in HIV controllers. CONCLUSIONS: Our results suggest that despite the infection, HIV controllers have preserved immune parameters, which can be associated with the spontaneous control of viral replication.

Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters

Agave tequilana Weber var. 'Azul' is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost.

Multistage quantum absorption heat pumps.

It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N-2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration.

Quantum-enhanced absorption refrigerators.

Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step towards the technological exploitation of autonomous quantum refrigerators.

Optimal performance of endoreversible quantum refrigerators.

The derivation of general performance benchmarks is important in the design of highly optimized heat engines and refrigerators. To obtain them, one may model phenomenologically the leading sources of irreversibility ending up with results that are model independent, but limited in scope. Alternatively, one can take a simple physical system realizing a thermodynamic cycle and assess its optimal operation from a complete microscopic description. We follow this approach in order to derive the coefficient of performance at maximum cooling rate for any endoreversible quantum refrigerator. At striking variance with the universality of the optimal efficiency of heat engines, we find that the cooling performance at maximum power is crucially determined by the details of the specific system-bath interaction mechanism. A closed analytical benchmark is found for endoreversible refrigerators weakly coupled to unstructured bosonic heat baths: an ubiquitous case study in quantum thermodynamics.

Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters.

Agave tequilana Weber var. 'Azul' is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost.

Performance bound for quantum absorption refrigerators.

An implementation of quantum absorption chillers with three qubits has been recently proposed that is ideally able to reach the Carnot performance regime. Here we study the working efficiency of such self-contained refrigerators, adopting a consistent treatment of dissipation effects. We demonstrate that the coefficient of performance at maximum cooling power is upper bounded by 3/4 of the Carnot performance. The result is independent of the details of the system and the equilibrium temperatures of the external baths. We provide design prescriptions that saturate the bound in the limit of a large difference between the operating temperatures. Our study suggests that delocalized dissipation, which must be taken into account for a proper modeling of the machine-baths interaction, is a fundamental source of irreversibility which prevents the refrigerator from approaching the Carnot performance arbitrarily closely in practice. The potential role of quantum correlations in the operation of these machines is also investigated.

Induction of transplantation tolerance by allogeneic donor-derived CD4(+)CD25(+)Foxp3(+) regulatory T cells.

Several studies have shown that recipient-derived CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) are involved in transplantation tolerance. However, it is not clear whether allogeneic donor-derived Tregs are able to regulate T cell alloreactivity after solid organ allograft transplantation. Related studies in experimental bone marrow transplantation have shown that allogeneic donor-derived Tregs are capable of promoting early and long-term allogeneic hematopoietic engraftment, accompanied by tolerance to donor and recipient antigens. However, in these models, donor-derived Tregs are syngeneic with respect to the T responder cells. The role of Tregs in solid organ transplantation models where recipient-derived T responder and donor-derived Tregs are allogeneic has been scarcely studied. In order to determine whether allogeneic Tregs were able to regulate T cell alloreactivity, CD4(+)CD25(-) and CD8(+) T responder cells were cultured with stimulator dendritic cells in several responder-stimulator strain combinations (C57BL/6-->BALB/c, BALB/c-->C57BL/6 and C3H-->BALB/c) in the presence of responder-derived, stimulator-derived or 3rd-party-derived Tregs. Then, the frequency of IFN-gamma+ alloreactive T cells was determined by means of ELISPOT assay. The results of this study demonstrate that, regardless of the responder-stimulator strain combination, both responder-derived and stimulator-derived Tregs, but not 3rd-party-derived Tregs, significantly inhibited CD4(+) and CD8(+) T cell alloreactivity. The effect of allogeneic stimulator-derived Tregs was dependent on IL-10 and TGF-beta and reversed by exogenous IL-2. In vivo experiments in nu/nu recipients reconstituted with CD4(+)CD25(-) T responder and Tregs showed that recipient and donor-derived, but not 3rd-party-derived Tregs, significantly enhanced skin allograft survival. Importantly, T cells from both recipient-derived and donor-derived Treg-reconstituted nu/nu recipients exhibited donor-specific unresponsiveness in vitro. These results show that allogeneic donor-derived Tregs significantly inhibit T cell alloreactivity and suggest their potential use in the induction of transplantation tolerance.