Circular dielectric cavity and its deformations

The construction of perturbation series for slightly deformed dielectric circular cavity is discussed in details. The obtained formulae are checked on the example of cut disks. A good agreement is found with direct numerical simulations and far-field experiments.Comment: 17 pages, 12 figure

Converted phase identification and retrieval of Vp/Vs ratios from move-out reflection analysis: application to the Campi Flegrei caldera

Here, we propose a method for the determination of Vp/Vs ratios in a horizontally layered propagation media using maximization of a coherency function along theoretical travel-times of PS reflected phases. The theoretical travel-times are computed using the information about the propagation media that is extracted by velocity analysis or by topographic analysis performed on the first arrivals. The method is also a valid tool for the identification of the PS phases associated with a fixed seismic reflector, and it is particularly suitable for data that is stored in common mid-point and common conversion point bin- ning; for this kind of data the hypothesis of horizontally and layered media can usually be verified. We applied the method to both simulated and real datasets. The use of the real data that was acquired in the Campi Flegrei caldera (southern Italy) allowed us to estimate a relatively high Vp/Vs ratio (3.5 ± 0.6) for a very shallow layer (maximum depth, 600 m). This hypothesis has been tested by theoretical rock physical modeling of the Vp/Vs ratios as a function of porosity, suggesting that the shallow layer appears to be formed of unconsolidated, water-saturated, volcanic and marine sediments that filled Pozzuoli Bay during the post-caldera activity

Experimental Test of a Two-dimensional Approximation for Dielectric Microcavities

Open dielectric resonators of different shapes are widely used for the manufacture of microlasers. A precise determination of their resonance frequencies and widths is crucial for their design. Most microlasers have a flat cylindrical geometry, and a two-dimensional approximation, the so-called method of the effective index of refraction, is commonly employed for numerical calculations. Our aim has been an experimental test of the precision and applicability of a model based on this approximation. We performed very thorough and accurate measurements of the resonance frequencies and widths of two passive circular dielectric microwave resonators and found significant deviations from the model predictions. From this we conclude that the model generally fails in the quantitative description of three-dimensional dielectric resonators.Comment: 10 pages, 13 figure

Concomitant essential thrombocythemia with jak2 v617f mutation in a patient with chronic myeloid leukemia with major molecular response with imatinib and long-term follow-up

The association of chronic myeloid leukemia (CML) with other myeloproliferative neoplasms (MPNs), in particular with the V617F mutation in the Janus kinase 2 (JAK2) gene, is very uncommon, and there are only a few cases reported in the literature. In the present study, the case of a 73-year-old man with CML and persistent thrombocytosis, is reported. The patient achieved a complete cytogenetic response and major molecular response (MR) with imatinib. The patient presented JAK2 V617F mutation, and bone marrow morphology was consistent with essential thrombocythemia. The patient was treated with imatinib and hydroxyurea to control the platelet count, and maintains complete MR with imatinib upon 10 years of follow-up. Although rare, the association of breakpoint cluster region-Abelson rearrangement and JAK2 V617F mutation should be investigated in patients with MPN, since both genetic anomalies may be present at diagnosis or may emerge during treatment, and require different therapeutic approaches.The association of chronic myeloid leukemia (CML) with other myeloproliferative neoplasms (MPNs), in particular with the V617F mutation in the Janus kinase 2 (JAK2) gene, is very uncommon, and there are only a few cases reported in the literature. In the121485487sem informaçãosem informaçã

Inferring periodic orbits from spectra of simple shaped micro-lasers

Dielectric micro-cavities are widely used as laser resonators and characterizations of their spectra are of interest for various applications. We experimentally investigate micro-lasers of simple shapes (Fabry-Perot, square, pentagon, and disk). Their lasing spectra consist mainly of almost equidistant peaks and the distance between peaks reveals the length of a quantized periodic orbit. To measure this length with a good precision, it is necessary to take into account different sources of refractive index dispersion. Our experimental and numerical results agree with the superscar model describing the formation of long-lived states in polygonal cavities. The limitations of the two-dimensional approximation are briefly discussed in connection with micro-disks.Comment: 13 pages, 19 figures, accepted for publication in Physical Review

Deep learning to segment liver metastases on CT images: Impact on a radiomics method to predict response to chemotherapy

Predicting response to neo-adjuvant chemotherapy of liver metastases (mts) using CT images is of key importance to provide personalized treatments. However, manual segmentation of mts should be avoid to develop methods that could be integrated into the clinical practice. The aim of this study is to evaluate if and how much automatic segmentation can affect a radiomics-based method to predict response to neoadjuvant chemotherapy of individual liver mts. To this scope, we developed an automatic deep learning method to segment liver mts, based on the U-net architecture, and we compared the classification results of a classifier fed with manual and automatic masks. In the validation set composed of 39 liver mts, the automatic deeplearning algorithm was able to detect 82% of mts, with a median precision of 67%. Using manual and automatic masks, we obtained the same classification in 19/32 mts. In case of mts with largest diameter > 20 mm, the precision of the segmentation does not impact the classification results and we obtained the same classification with both masks. Conversely, with smaller mts, we showed that a Dice coefficient of at least 0.5 should be obtained to extract the same information from the two segmentations. This are very important results in the perspective of using radiomics-based approach to predict response to therapy into clinical practice. Indeed, either precisely manually segment all lesions or refine them after automatic segmentation is a time-consuming task that cannot be performed on a daily basis

Inflammation and muscle weakness in COPD: Considering a renewed role for Theophylline?

© 2018 Bentham Science Publishers. Background: The methyl-xanthine drug theophylline has been used for the treatment of asthma and chronic obstructive pulmonary disease (COPD) for several decades. Phosphodiesterase inhibition leading to smooth muscle relaxation is its main mode of action as a broncho-dilating agent, requiring blood theophylline concentrations close to the toxic range and a consequent problem with side effects. It also has anti-inflammatory effects that occur at relatively low concentrations. Objective: To explore supporting evidence for how other properties of theophylline could be of considerable clinical utility, particularly in reducing weakness and overt sarcopenia, based on its antiinflammatory, steroid-sparing and immune-modulating properties. Methods: PUBMED and MEDLINE were scanned using the search terms: theophylline, antiinflammatory, cytokine, inflammation, ageing, sarcopenia, frailty, chronic obstructive airways disease, pulmonary rehabilitation. High quality articles were selected, read in-depth and discussed by the authors, then used as the basis for a proposition on the potential anti-inflammatory and antisarcopenic use of theophylline. Findings: The anti-inflammatory properties of theophylline are mainly mediated by histone deacetylase induction in immune competent cells with a resulting shift toward the expression of a less inflamed phenotype, including a reduction of the release of pro-inflammatory cytokines and the associated increase in anti-inflammatory cytokines. These effects occur at blood theophylline concentrations well below the range for direct broncho-dilatation. Conclusion: There are potential therapeutic benefits of theophylline that are systemic and not confined to airways inflammation in COPD. There is scope for a beneficial effect in other chronic inflammatory states and post-acute inflammation with slow resolution. There is compelling evidence that theophylline could be used for anti-inflammatory adjunctive treatment to improve independent function, muscle strength and other outcomes in individuals recovering from acute inflammatory episodes, including but not limited to exacerbations of COPD, and as a pharmaceutical intervention in support of pulmonary rehabilitation

Inflammatory cytokines may mediate cognitive dysfunction and sickness behavior during acute illness

Background Delirium is characterized by acute cognitive dysfunction and sickness behaviour during an acute illness, but its pathophysiology remains unclear. Objective To determine the role of inflammatory cytokines in mediating cognitive dysfunction and sickness behaviour during acute illness. Methods We recruited 15 patients admitted with acute bacterial sepsis, 11 with non-sepsis-related acute conditions, and 38 normal healthy controls. At weeks 0, 1, 2 and 6, blood inflammatory cytokines were measured, and cognition and sickness behaviour were also assessed using the Mini Mental State Examination (MMSE, low score indicating poor cognition) and Cornell Scale for Depression in Dementia (CSDD, high score indicating more sickness behaviour), respectively. Results Mean age was 52 (±15) years, 54% were females. In the sepsis group, IL1 and IL4 at week 0 were negatively correlated with MMSE (p=.04 and p=.008 respectively), and TNFα positively correlated to MMSE (p=.009); no correlation was found with CSDD. Most significant correlations were seen in the non-sepsis group: IL4, IL6 and TNFα at week 1 were negatively correlated to MMSE (p=.049, p=.049, p=.046 respectively), and IL6 and TNFα positively correlated to CSDD (p=.068, p=.009 respectively). Moreover, TNFα, IL4 and IL6 at week 2 was positively correlated to CSDD (p=.016, p=.038, p=.046 respectively). And lastly, IL10 at week 6 was negatively correlated with MMSE (p=.009). As expected, no correlations between CSDD, MMSE and cytokines were found in the healthy controls. Conclusions Inflammatory cytokines may mediate cognitive dysfunction and sickness behaviour during acute illness. These results may enhance the understanding of the pathophysiology and potential treatment strategies of delirium