1,396 research outputs found
Improving Rigid 3-D Calibration for Robotic Surgery
Autonomy is the next frontier of research in robotic surgery and its aim is to improve the quality of surgical procedures in the next future. One fundamental requirement for autonomy is advanced perception capability through vision sensors. In this article, we propose a novel calibration technique for a surgical scenario with a da Vinci Research Kit (dVRK) robot. Camera and robotic arms calibration are necessary to precise position and emulate expert surgeon. The novel calibration technique is tailored for RGB-D cameras. Different tests performed on relevant use cases prove that we significantly improve precision and accuracy with respect to state of the art solutions for similar devices on a surgical-size setups. Moreover, our calibration method can be easily extended to standard surgical endoscope used in real surgical scenario
Vessels in a Rhododendron ferrugineum (L.) population do not trace temperature anymore at the alpine shrubline
Introduction Mean xylem vessel or tracheid area have been demonstrated to represent powerful proxies to better understand the response of woody plants to changing climatic conditions. Yet, to date, this approach has rarely been applied to shrubs. MethodsHere, we developed a multidecadal, annually-resolved chronology of vessel sizes for Rhododendron ferrugineum shrubs sampled at the upper shrubline (2,550 m asl) on a north-facing, inactive rock glacier in the Italian Alps. Results and DiscussionOver the 1960-1989 period, the vessel size chronology shares 64% of common variability with summer temperatures, thus confirming the potential of wood anatomical analyses on shrubs to track past climate variability in alpine environments above treeline. The strong winter precipitation signal recorded in the chronology also confirms the negative effect of long-lasting snow cover on shrub growth. By contrast, the loss of a climate-growth relation signal since the 1990s for both temperature and precipitation, significantly stronger than the one found in radial growth, contrasts with findings in other QWA studies according to which stable correlations between series of anatomical features and climatic parameters have been reported. In a context of global warming, we hypothesize that this signal loss might be induced by winter droughts, late frost, or complex relations between increasing air temperatures, permafrost degradation, and its impacts on shrub growth. We recommend future studies to validate these hypotheses on monitored rock glaciers
Theoretical and Experimental Investigation of the Tb3+-Eu3+ Energy Transfer Mechanisms in Cubic A3Tb0.90Eu0.10({PO}4)3 (A = Sr, Ba) Materials
In this study the optical spectroscopy, the excited state dynamics, and in particular the Tb3+ -> Eu3+ energy transfer, have been investigated in detail both from the theoretical and experimental point of view in eulytite double phosphate hosts A(3)Tb(PO4)(3) (A = Sr, Ba) doped with Eu3+. It has been found that the energy transfer is strongly assisted by fast migration in the donor Tb3+ subset. Moreover, the transfer rates and efficiencies depend significantly on the nature of the divalent elements present in the structure and hence on the distances between Tb3+-Eu3+ nearest neighbors. It is shown that the competition between quadrupole-quadrupole and exchange interaction is crucial in accounting for the transfer rates
Anemia and acute coronary syndrome: current perspectives
Reference hemoglobin (Hb) values for the definition of anemia are still largely based on the 1968 WHO Scientific Group report, which established a cutoff value of <13 g/dL for adult men and <12 g/dL for adult nonpregnant women. Subsequent studies identified different normal values according to race and age. Estimated prevalence of anemia on admission in the setting of an acute coronary syndrome (ACS) is between 10% and 43% of the patients depending upon the specific population under investigation. Furthermore, up to 57% of ACS patients may develop hospital-acquired anemia (HAA). Both anemia on admission and HAA are associated with worse short- and long-term mortality, even if different mechanisms contribute to their prognostic impact. Baseline anemia can usually be traced back to preexisting disease that should be specifically investigated and corrected whenever possible. HAA is associated with clinical characteristics, medical therapy and interventional procedures, all eliciting cardiovascular adaptive response that can potentially worsen myocardial ischemia. The intrinsic fragility of anemic patients may limit aggressive medical and interventional therapy due to an increased risk of bleeding, and could independently contribute to worse outcome. However, primary angioplasty for ST elevation ACS should not be delayed because of preexisting (and often not diagnosed) anemia; delaying revascularization to allow fast-track anemia diagnosis is usually feasible and justified in non-ST-elevation ACS. Besides identification and treatment of the underlying causes of anemia, the only readily available means to reverse anemia is red blood cell transfusion. The adequate transfusion threshold is still being debated, although solid evidence suggests reserving red blood cell transfusions for patients with Hb level <8 g/dL and considering it in selected cases with Hb levels of between 8 and 10 g/dL. No evidence supports the use of iron supplements and erythropoiesis-stimulating agents in the setting of ACS
Faraday rotation, stochastic magnetic fields and CMB maps
The high- and low-frequency descriptions of the pre-decoupling plasma are
deduced from the Vlasov-Landau treatment generalized to curved space-times and
in the presence of the relativistic fluctuations of the geometry. It is
demonstrated that the interplay between one-fluid and two-fluid treatments is
mandatory for a complete and reliable calculation of the polarization
observables. The Einstein-Boltzmann hierarchy is generalized to handle the
dispersive propagation of the electromagnetic disturbances in the
pre-decoupling plasma. Given the improved physical and numerical framework, the
polarization observables are computed within the magnetized CDM
paradigm (mCDM). In particular, the Faraday-induced B-mode is
consistently estimated by taking into account the effects of the magnetic
fields on the initial conditions of the Boltzmann hierarchy, on the dynamical
equations and on the dispersion relations. The complete calculations of the
angular power spectra constitutes the first step for the derivation of
magnetized maps of the CMB temperature and polarization which are here obtained
for the first time and within the minimal mCDM model. The obtained
results set the ground for direct experimental scrutiny of large-scale
magnetism via the low and high frequency instruments of the Planck explorer
satellite.Comment: 53 pages, 15 included figure
Fermion scattering off electroweak phase transition kink walls with hypermagnetic fields
We study the scattering of fermions off a finite width kink wall during the
electroweak phase transition in the presence of a background hypermagnetic
field. We derive and solve the Dirac equation for such fermions and compute the
reflection and transmission coefficients for the case when the fermions move
from the symmetric to the broken symmetry phase. We show that the chiral nature
of the fermion coupling with the background field in the symmetric phase
generates an axial asymmetry in the scattering processes. We discuss possible
implications of such axial charge segregation for baryon number generation.Comment: 9 pages, 3 Postscript figures, uses RevTeX4. Expanded discussion,
published versio
Dynamics of the Energy Transfer Process in Eu(III) Complexes Containing Polydentate Ligands Based on Pyridine, Quinoline, and Isoquinoline as Chromophoric Antennae
In this work, we investigated from a theoretical point of view the dynamics of the energy transfer process from the ligand to Eu(III) ion for 12 isomeric species originating from six different complexes differing by nature of the ligand and the total charge. The cationic complexes present the general formula [Eu(L)(H2O)2]+ (where L = bpcd2- = N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate; bQcd2- = N,N'-bis(2-quinolinmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate; and bisoQcd2- = N,N'-bis(2-isoquinolinmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate), while the neutral complexes present the Eu(L)(H2O)2 formula (where L = PyC3A3- = N-picolyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetate; QC3A3- = N-quinolyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetate; and isoQC3A3- = N-isoquinolyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetate). Time-dependent density functional theory (TD-DFT) calculations provided the energy of the ligand excited donor states, distances between donor and acceptor orbitals involved in the energy transfer mechanism (RL), spin-orbit coupling matrix elements, and excited-state reorganization energies. The intramolecular energy transfer (IET) rates for both singlet-triplet intersystem crossing and ligand-to-metal (and vice versa) involving a multitude of ligand and Eu(III) levels and the theoretical overall quantum yields (ϕovl) were calculated (the latter for the first time without the introduction of experimental parameters). This was achieved using a blend of DFT, Judd-Ofelt theory, IET theory, and rate equation modeling. Thanks to this study, for each isomeric species, the most efficient IET process feeding the Eu(III) excited state, its related physical mechanism (exchange interaction), and the reasons for a better or worse overall energy transfer efficiency (ηsens) in the different complexes were determined. The spectroscopically measured ϕovl values are in good agreement with the ones obtained theoretically in this work
Functional analysis of novel KCNQ2 and KCNQ3 gene variants found in a large pedigree with benign familial neonatal convulsions (BFNC)
Benign familial neonatal convulsion (BFNC) is a rare autosomal dominant disorder caused by mutations in KCNQ2 and KCNQ3, two genes encoding for potassium channel subunits. A large family with nine members affected by BFNC is described in the present study. All affected members of this family carry a novel deletion/insertion mutation in the KCNQ2 gene (c.761_770del10insA), which determines a premature truncation of the protein. In addition, in the family of the proposita's father, a novel sequence variant (c.2687A>G) in KCNQ3 leading to the p.N821S amino acid change was detected. When heterologously expressed in Chinese hamster ovary cells, KCNQ2 subunits carrying the mutation failed to form functional potassium channels in homomeric configuration and did not affect channels formed by KCNQ2 and/or KCNQ3 subunits. On the other hand, homomeric and heteromeric potassium channels formed by KCNQ3 subunits carrying the p.N821S variant were indistinguishable from those formed by wild-type KCNQ3 subunits. Finally, the current density of the cells mimicking the double heterozygotic condition for both KCNQ2 and KCNQ3 alleles of the proband was decreased by approximately 25% when compared to cells expressing only wild-type alleles. Collectively, these results suggest that, in the family investigated, the KCNQ2 mutation is responsible for the BFNC phenotype, possibly because of haplo-insufficiency, whereas the KCNQ3 variant is functionally silent, a result compatible with its lack of segregation with the BFNC phenotyp
Cross-sectional survey of users of internet depression communities
Background: Internet-based depression communities provide a forum for individuals to
communicate and share information and ideas. There has been little research into the health status
and other characteristics of users of these communities.
Methods: Online cross-sectional survey of Internet depression communities to identify depressive
morbidity among users of Internet depression communities in six European countries; to
investigate whether users were in contact with health services and receiving treatment; and to
identify user perceived effects of the communities.
Results: Major depression was highly prevalent among respondents (varying by country from 40%
to 64%). Forty-nine percent of users meeting criteria for major depression were not receiving
treatment, and 35% had no consultation with health services in the previous year. Thirty-six
percent of repeat community users who had consulted a health professional in the previous year
felt that the Internet community had been an important factor in deciding to seek professional help.
Conclusions: There are high levels of untreated and undiagnosed depression in users of Internet
depression communities. This group represents a target for intervention. Internet communities can
provide information and support for stigmatizing conditions that inhibit more traditional modes of
information seeking
Upadacitinib effectiveness and factors associated with minimal disease activity achievement in patients with psoriatic arthritis: preliminary data of a real-life multicenter study
Background: Upadacitinib (UPA) is a selective JAK inhibitor recently approved for the treatment of psoriatic arthritis (PsA). In this post-approval study, we aimed to evaluate the effectiveness and safety of UPA over 24 weeks and identify clinical predictors of response, in a multicentric cohort of patients affected by PsA. Methods: One hundred and twenty-six patients with PsA treated with UPA were enrolled in 10 Italian centres. UPA effectiveness outcomes, such as the proportion of patients with MDA status, DAPSA remission, and low disease activity, ASDAS-CRP inactive and low disease activity, and change from baseline in DAPSA and ASDAS-CRP scores, were evaluated every 12 weeks until week 24. The proportion of DAPSA minor, moderate, and major improvement, and ASDAS clinically important improvement (CII) and major improvement (MI) were considered as well. All treatment-related adverse events were collected during the observation period. Clinical predictors of MDA response at week 24 were evaluated through multivariate analysis. Results: At baseline, 124/126 (98%) and 54/126 (43%) patients showed peripheral and axial involvement, respectively; 110 (87%) patients were intolerant or resistant to biologic DMARDs. At 24 weeks, MDA status, DAPSA remission, and ASDAS-CRP inactive disease were achieved in 47%, 23%, and 48% of patients, respectively. Minor, moderate, and major DAPSA improvement was observed in 67%, 39%, and 23%, respectively; while 65% and 35% achieved ASDAS-CRP CII and MI, respectively. The mean change from baseline was 15.9 ± 13.5 (p < 0.001) for DAPSA and 1.21 ± 0.97 (p < 0.001) for ASDAS-CRP. Thirteen patients (10%) discontinued UPA due to a lack of efficacy or non-serious adverse events. No serious adverse events were observed. Male gender (OR 2.54, 95% CI 1.03-6.25 p = 0.043), being naïve to biological DMARDs (OR 4.13, 95% CI 1.34-12.71, p = 0.013) and elevated baseline CRP (OR 2.49, 95% CI 1.02-6.12, p = 0.046) were associated with MDA response at week 24. Conclusions: This is one of the first real-life studies supporting the effectiveness of UPA and its safety profile in PsA patients. Furthermore, the study identifies predictors of MDA response to UPA treatment at 6 months
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