We report on the optical identification of the companion star to the eclipsing millisecond pulsar (MSP) PSR J1824--2452H in the galactic globular cluster M28 (NGC 6626). This star is at only 02 from ...the nominal position of the pulsar and it shows optical variability (~0.25 mag) that nicely correlates with the pulsar orbital period. It is located on the blue side of the cluster main sequence, ~1.5 mag fainter than the turnoff point. The observed light curve shows two distinct and asymmetric minima, suggesting that the companion star is suffering tidal distortion from the pulsar. This discovery increases the number of non-degenerate MSP companions optically identified so far in globular clusters (four out of seven), suggesting that these systems could be a common outcome of the pulsar recycling process, at least in dense environments where they can be originated by exchange interactions.
The catalytic cutting of few-layer graphene is nowadays a hot topic in materials research due to its potential applications in the catalysis field and the graphene nanoribbons fabrication. We show ...here a 3D analysis of the nanostructuration of few-layer graphene by iron-based nanoparticles under hydrogen flow. The nanoparticles located at the edges or attached to the steps on the FLG sheets create trenches and tunnels with orientations, lengths and morphologies defined by the crystallography and the topography of the carbon substrate. The cross-sectional analysis of the 3D volumes highlights the role of the active nanoparticle identity on the trench size and shape, with emphasis on the topographical stability of the basal planes within the resulting trenches and channels, no matter the obstacle encountered. The actual study gives a deep insight on the impact of nanoparticles morphology and support topography on the 3D character of nanostructures built up by catalytic cutting.
The use of coherent anti-Stokes Raman scattering microscopy tuned to the lipid vibration for quantitative myelin imaging suffers from the excitation polarization dependence of this third-order ...nonlinear optical effect. The contrast obtained depends on the orientation of the myelin membrane, which in turn affects the morphometric parameters that can be extracted with image analysis. We show how circularly polarized laser beams can be used to avoid this complication, leading to images free of excitation polarization dependence. The technique promises to be optimal for in vivo imaging and the resulting images can be used for coherent anti-Stokes Raman scattering optical histology on native state tissue.
Importance Inappropriate variations in clinical practice are a known cause of poor quality and safety, with variations often associated with nonclinical factors, such as individual differences in ...cognitive processing. The differential response of physicians to uncertainty may explain some of the variations in resource use and patient experience. Objective To examine the association of physician tolerance for uncertainty with variations in resource use and patient experience. Design, Setting, and Participants This survey study linked physician survey data (May to June 2019), patient experience survey data (January 2016 to December 2019), and billing data (January 2019 to December 2019) among primary care physicians (PCPs) at Massachusetts General Hospital with at least 10 visits in 2019. The statistical analysis was performed in 2021. Main Outcomes and Measures The analysis examined associations of PCP tolerance for uncertainty with the tendency to order diagnostic tests, the frequency of outpatient visits, hospital admissions, emergency department visits, and patient experience data (focused on physician communication and overall rating). A 2-stage hierarchical framework was used to account for clustering of patients under PCPs. Binary outcomes were modeled using a hierarchical logistic model, and count outcomes were modeled using hierarchical Poisson or negative binomial models. The analysis was adjusted for patient demographic variables (age, sex, and race and ethnicity), socioeconomic factors (payer and neighborhood income), and clinical comorbidities. Results Of 217 included physicians, 137 (63.1%) were women, and 174 (80.2%) were adult PCPs. A total of 62 physicians (28.6%) reported low tolerance, 59 (27.2%) reported medium tolerance, and 96 (44.2%) reported high tolerance for uncertainty. Physicians with a low tolerance for uncertainty were less likely to order complete blood cell counts (odds ratio OR, 0.66; 95% CI, 0.50-0.88), thyroid tests (OR, 0.67; 95% CI, 0.52-0.88), a basic metabolic profile (OR, 0.78; 95% CI, 0.60-1.00), and liver function tests (OR, 0.72; 95% CI, 0.53-0.99) than physicians with a high tolerance for uncertainty. Physicians who reported higher tolerance for uncertainty were more likely to receive higher patient experience scores for listening to patients carefully (OR, 0.65; 95% CI, 0.50-0.83) and higher overall ratings (OR, 0.80; 95% CI, 0.66-0.98) than physicians with medium tolerance. Conversely, no association was found between physician tolerance for uncertainty and patient outpatient visits, hospital admissions, or emergency department visits. Conclusions and Relevance In clinical practice, identifying and effectively managing inappropriate variations and improving patient experience have proven to be difficult, despite increased attention to these issues. This study supports the hypothesis that physicians’ tolerance for uncertainty is associated with differences in resource use and patient experience. Whether enhancing physicians’ tolerance for uncertainty could help reduce unwarranted practice variations, improve quality and patient safety, and improve patient’s experience remains to be established.
Graphene and carbon nanotubes are envisaged as suitable materials for the fabrication of the new generation of nanoelectronics. The controlled patterning of such nanostructures with metal ...nanoparticles is conditioned by the transfer between a recipient and the surface to pattern. Electromigration under the impact of an applied voltage stands at the base of printing discrete digits at the nanoscale. Here we report the use of carbon nanotubes as nanoreservoirs for iron nanoparticles transfer on few-layer graphene. An initial Joule-induced annealing is required to ensure the control of the mass transfer with the nanotube acting as a 'pen' for the writing process. By applying a voltage, the tube filled with metal nanoparticles can deposit metal on the surface of the graphene sheet at precise locations. The reverse transfer of nanoparticles from the graphene surface to the nanotube when changing the voltage polarity opens the way for error corrections.
The biodistribution of dendronized iron oxides, NPs10@D1_DOTAGA and melanin-targeting NPs10@D1_ICF_DOTAGA, was studied in vivo using magnetic resonance imaging (MRI) and planar scintigraphy through ...177LuLu-radiolabeling. MRI experiments showed high contrast power of both dendronized nanoparticles (DPs) and hepatobiliary and urinary excretions. Little tumor uptake could be highlighted after intravenous injection probably as a consequence of the negatively charged DOTAGA-derivatized shell, which reduces the diffusion across the cells’ membrane. Planar scintigraphy images demonstrated a moderate specific tumor uptake of melanoma-targeted 177LuLu-NPs10@D1_ICF_DOTAGA at 2 h post-intravenous injection (pi), and the highest tumor uptake of the control probe 177LuLu-NPs10@D1_DOTAGA at 30 min pi, probably due to the enhanced permeability and retention effect. In addition, ex vivo confocal microscopy studies showed a high specific targeting of human melanoma samples impregnated with NPs10@D1_ICF_Alexa647_ DOTAGA.
The design and the functionalisation of nanoparticles is a promising way to elaborate new functional materials, with combined or coupled properties (magnetic, optical, optoelectronic …). In this ...context, the direct binding of functional organic conjugated molecules (stilbene derivative) onto the surface of monodisperse Fe
3O
4 magnetic nanoparticles has been studied. Monodisperse Fe
3O
4 nanoparticles have been synthesized by adjusting the conditions of precipitation and growth and then stilbene derivatives have been grafted onto the surface of these nanoparticles using either phosphonate or carboxylate groups as coupling agents. The functionalised nanoparticles have been characterized before and after grafting by several techniques (XRD, UV, TEM). Studies have demonstrated that the phosphonate coupling agent allows a higher grafting rate than with the carboxylate coupling agent. The nanoparticles functionalised via carboxylate groups are less stable than those functionalised with phosphonate groups mainly due to a strong P–O–Fe bonding. The coated magnetite nanoparticles retain their intrinsic magnetic properties.
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