Closed time path approach to the Casimir energy in real media

The closed time path formalism is applied, in the framework of open quantum systems, to study the time evolution of the expectation value of the energy-momentum tensor of a scalar field in the presence of real materials. We analyze quantum fluctuations in a fully non-equilibrium scenario, when the scalar field is interacting with the polarization degrees of freedom of matter, described as quantum Brownian particles. A generalized analysis was done for two types of couplings between the field and the material. On the one hand, we considered a bilinear coupling, and on the other hand, a (more realistic) current-type coupling as in the case of the electromagnetic field interacting with matter. We considered the high temperature limit for the field, keeping arbitrary temperatures for each part of the volume elements of the material. We obtained a closed form for the Hadamard propagator, which let us study the dynamical evolution of the expectations values of the energy-momentum tensor components from the initial time. We showed that two contributions always take place in the transient evolution: one of these is associated to the material and the other one is only associated to the field. Transient features were studied and the long-time limit was derived in several cases. We proved that in the steady situation of a field in n + 1 dimensions, the material always contribute unless is non-dissipative. Conversely, the proper field contribution vanishes unless the material is non-dissipative or, moreover, at least for the 1 + 1 case, if there are regions without material. We conclude that any steady quantization scheme in 1 + 1 dimensions must consider both contributions and we argue why these results are physically expected from a dynamical point of view, and also could be valid for higher dimensions based on the expected continuity between the non-dissipative and real material cases.Comment: 28 pages, no figures. Version to appear in Phys. Rev.

Non-equilibrium Lifshitz theory as a steady state of a full dynamical quantum system

In this work we analyze the validity of Lifshitz's theory for the case of non-equilibrium scenarios from a full quantum dynamical approach. We show that Lifshitz's framework for the study of the Casimir pressure is the result of considering the long-time regime (or steady state) of a well-defined fully quantized problem, subjected to initial conditions for the electromagnetic field interacting with real materials. For this, we implement the closed time path formalism developed in previous works to study the case of two half spaces (modeled as composite environments, consisting in quantum degrees of freedom plus thermal baths) interacting with the electromagnetic field. Starting from initial uncorrelated free subsystems, we solve the full time evolution, obtaining general expressions for the different contributions to the pressure that take part on the transient stage. Using the analytic properties of the retarded Green functions, we obtain the long-time limit of these contributions to the total Casimir pressure. We show that, in the steady state, only the baths' contribute, in agreement with the results of previous works, where this was assumed without justification. We also study in detail the physics of the initial conditions' contribution and the concept of modified vacuum modes, giving insights about in which situations one would expect a non vanishing contribution at the steady state of a non-equilibrium scenario. This would be the case when considering finite width slabs instead of half-spaces

Quantum electrodynamics of inhomogeneous anisotropic media

In this work we calculate the closed time path (CTP) generating functional for the electromagnetic (EM) field interacting with inhomogeneous anisotropic matter. For this purpose, we first find a general expression for the electromagnetic field's influence action from the interaction of the field with a composite environment consisting in the quantum polarization degrees of freedom in each point of space, at arbitrary temperatures, connected to thermal baths. Then, we evaluate the generating functional for the gauge field, in the temporal gauge, by implementing the Faddeev-Popov procedure. Finally, through the point-splitting technique, we calculate closed expressions for the energy, the Poynting vector and the Maxwell tensor in terms of the Hadamard propagator. We show that all the quantities have contributions from the field's initial conditions and also from the matter degrees of freedom. Throughout the whole work we discuss and give insights about how the gauge invariance must be treated in the formalism when the EM field is interacting with inhomogeneous anisotropic matter. We study the electrodynamics in the temporal gauge, obtaining the EM field's equation and a residual condition. Finally analyze the case of the EM field in bulk material and also discuss several general implications of our results in relation with the Casimir physics in a nonequilibrium scenario.Comment: 15 page

Toca 511 gene transfer and treatment with the prodrug, 5-fluorocytosine, promotes durable antitumor immunity in a mouse glioma model.

BackgroundToca 511 (vocimagene amiretrorepvec) is a retroviral replicating vector encoding an optimized yeast cytosine deaminase (CD). Tumor-selective expression of CD converts the prodrug, 5-fluorocytosine (5-FC), into the active chemotherapeutic, 5-fluorouracil (5-FU). This therapeutic approach is being tested in a randomized phase II/III trial in recurrent glioblastoma and anaplastic astrocytoma (NCT0241416). The aim of this study was to identify the immune cell subsets contributing to antitumor immune responses following treatment with 5-FC in Toca 511-expressing gliomas in a syngeneic mouse model.MethodsFlow cytometry was utilized to monitor and characterize the immune cell infiltrate in subcutaneous Tu-2449 gliomas in B6C3F1 mice treated with Toca 511 and 5-FC.ResultsTumor-bearing animals treated with Toca 511 and 5-FC display alterations in immune cell populations within the tumor that result in antitumor immune protection. Attenuated immune subsets were exclusive to immunosuppressive cells of myeloid origin. Depletion of immunosuppressive cells temporally preceded a second event which included expansion of T cells which were polarized away from Th2 and Th17 in the CD4+ T cell compartment with concomitant expansion of interferon gamma-expressing CD8+ T cells. Immune alterations correlated with clearance of Tu-2449 subcutaneous tumors and T cell-dependent protection from future tumor challenge.ConclusionsTreatment with Toca 511 and 5-FC has a concentrated effect at the site of the tumor which causes direct tumor cell death and alterations in immune cell infiltrate, resulting in a tumor microenvironment that is more permissive to establishment of a T cell mediated antitumor immune response

Portable integrated micro-fluidic platform for the monitoring and detection of nitrite

A wireless, portable integrated micro-fluidic platform is proposed and applied for the determination of nitrite anions in water. The colourimetric analysis of nitrite is based on the Griess reagent, and the colour intensity of nitrite Griess reagent complex is detected using a low cost Paired Emitter Detector Diode technique. The micro-fluidic device employed a photoswitchable micro-valve, controlled by white light and generated using a light emitting diode. This low-cost and low-power detector exhibited very low limits of detection (34 ± 0.1 μg L-1). Freshwater samples were analysed and the results were compared to those generated with a conventional UV-Vis spectrophotometer showing good agreement. The suitability of the analyser for the precise and continuous measurement of samples was established. In addition, its small size and low weight offered the advantage of portability, while its data logging capabilities allowed for independent nitrite monitoring. Moreover, integration of a wireless communication device allowed for the instrument to be controlled and results to be downloaded remotely

Radical radiotherapy in epidermoid cancer in the orbitary region: ideal scheme of hypo-fractionation in times of COVID-19: a case report

There are adverse events in the patient's environment that impact on therapeutic decisions and become a medical challenge, as is currently the management of cancer patients with radiotherapy, particularly the elderly in times of a COVID-19 pandemic, due the high risk of infection and fatal complications from non-cancer causes. Here we present the case of an 84-year-old woman with voluminous squamous cell cancer in the left orbital region, which caused intense pain, stench, and persistent bleeding. And due to persistence and time, it impacted with deterioration in the patient’s quality of life. In the end, of hypo fractionated radiotherapy management as the only modality, it evolves with a complete clinical response and total palliation of initial symptoms. The reasons for the decision to manage radiotherapy and the excellent clinical results that reinforce the idea of personalized medicine and the importance of evaluating the biopsychosocial environment of the cancer patient will be discussed

The smart sweatband

Real-time analysis of sweat loss is an exciting prospect for the sports industry. Replacing the fluids and electrolytes lost during exercise is vital to ensure adequate hydration which affects health and performance. We have developed a wearable device to provide immediate feedback to the user regarding the pH level of their sweat. An array of pH indicators are used to create a coloured barcode onto thin layers of poly(methyl methacrylate) (PMMA). The barcode sensor is flexible and can adapt to the contours of the body easily. It is integrated into a sweat band to be placed on different body regions e.g. forearm, wrist or forehead. A visual colour change is observed depending on the sweat pH, providing immediate physiological information to the athlete or coach during physical exercise. This colour change could also be monitored by cameras which are often already in place for kinematic analysis. We have also developed a wearable microfluidic device to sample and analyse small quantities of sweat. This work follows on from the EU FP6 BIOTEX project

Duration and quality of sleep and risk of physical function impairment and disability in older adults: Results from the ENRICA and ELSA Cohorts

Sleep duration and quality have been associated with poor physical function, but both the temporality of the association and the independence of sleep duration and quality are unclear. We examined the prospective association of sleep duration and quality with physical function impairment and disability in older adults. Data were taken from participants in the Seniors-ENRICA (2012-2015, n= 1,773) and in the ELSA cohort (waves 4 and 6, n=4,885) aged ≥60 years. Sleep duration and quality were self-reported. Physical function impairment and disability was obtained either from self-reports (ENRICA and ELSA) or from performance assessment (ENRICA). Logistic regression models were adjusted for potential confounders. After a follow-up of 2.0-2.8 years, no association was found between changes in sleep duration and physical function impairment or disability. However, in both studies, poor general sleep quality was linked to higher risk of impaired agility [OR: 1.93 (95% CI: 1.30-2.86) in Seniors-ENRICA and 1.65 (1.24-2.18) in ELSA study] and mobility [1.46 (0.98-2.17) in Seniors-ENRICA and 1.59 (1.18-2.15) in ELSA study]. Poor general sleep quality was also associated with decreased physical component summary (PCS) [1.39 (1.05-1.83)], disability in instrumental activities of daily living [1.59 (0.97-2.59)] and in basic activities of daily living [1.73 (1.14-2.64)] in Seniors-ENRICA. In addition, compared to those with no sleep complaints, participants with 2 or more sleep complaints had greater risk of impaired agility, impaired mobility, decreased PCS and impaired lower extremity function in both cohorts. Poor sleep quality was associated with higher risk of physical impairment and disability in older adults from Spain and from EnglandThe Seniors-ENRICA study was supported by FIS grants 13/0288, 16/609 and 16/1512 (Instituto de Salud Carlos III, State Secretary of R+D+I, and FEDER/FSE), the FRAILOMIC Initiative (FP7-HEALTH-2012-Proposal no. 305483-2), the ATHLOS project (EU H2020- Project ID: 635316) and the JPI HDHL (SALAMANDER project

Time Series of Sentinel-1 Interferometric Coherence and Backscatter for Crop-Type Mapping

The potential use of the interferometric coherence measured with Sentinel-1 satellites as input feature for crop classification is explored in this study. A one-year time series of Sentinel-1 images acquired over an agricultural area in Spain, in which 17 crop species are present, is exploited for this purpose. Different options regarding temporal baselines, polarisation, and combination with radiometric data (backscattering coefficient) are analysed. Results show that both radiometric and interferometric features provide notable classification accuracy when used individually (overall accuracy lies between 70% and 80%). It is found that the shortest temporal baseline coherences (6 days) and the use of all available intensity images perform best, hence proving the advantage of the 6-day revisit time provided by the Sentinel-1 constellation with respect to longer revisit times. It is also shown that dual-pol data always provide better classification results than single-pol ones. More importantly, when both coherence and backscattering coefficient are jointly used, a significant increase of accuracy is obtained (greater than 7% in overall accuracy). Individual accuracies of all crop types are increased, and an overall accuracy above 86% is reached. This proves that both features provide complementary information, and that the combination of interferometric and radiometric radar data constitute a solid information source for this application.This work was supported in part by the European Space Agency via the ESA SEOM Program ITT under Grant AO/1-8306/15/I-NB “SEOM-S14SCI Land,” and in part by the Spanish Ministry of Science, Innovation and Universities, the State Agency of Research (AEI), and the European Funds for Regional Development (EFRD) under Project TEC2017-85244-C2-1-P

Quasinormal modes from potentials surrounding the charged dilaton black hole

We clarify the purely imaginary quasinormal frequencies of a massless scalar perturbation on the 3D charged-dilaton black holes. This case is quite interesting because the potential-step appears outside the event horizon similar to the case of the electromagnetic perturbations on the large Schwarzschild-AdS black holes. It turns out that the potential-step type provides the purely imaginary quasinormal frequencies, while the potential-barrier type gives the complex quasinormal modes.Comment: 19 pages, 8 figure