417 research outputs found
Is it really useful the harmonic scalpel in axillary dissection for locally advanced breast cancer? A case series
Background. The seroma is one of the most common complications in the axillary lymph nodal dissection (different surgical approaches have been tried to reduce the seroma incidence). In our study we evaluate the outcome of patients using or not the ultrasonic scalpel (Harmonic scalpel) according to a standardized surgical technique. Patients and Methods. From January 2011 to December 2015 120 patients underwent axillary dissection for breast cancer. Patients were divided in two groups: patients belonging to the first group underwent Harmonic scalpel dissection and patients belonging to the second group underwent classical dissection. Each group consisted of 60 patients. Quadrantectomy (QUAD) was performed in 54 patients, 66 women underwent mastectomy. In all patients axillary dissection included the I, II and III level. We compared two groups in terms of: time of surgery, hematoma, drainage volume, days of sealing drainage, seroma formation, number of post-seroma aspirations, upper limb lymphedema, wound infections, post-operative pain. Results. Statistically significant results were obtained in terms of the total volume of the breast and axillary drainage in the two techniques. There were no significant differences in the two samples in terms of operative time incidence of seroma, post-operative hematoma, wound infection, and lymphedema of the upper limb. Conclusion. The small number of cases did not allow us to reach definitive conclusions. The use of Harmonic scalpel seems to show smaller incidence of seroma and reduction of the amount of both breast and axillary drainages. Further studies are needed to define the real advantage in terms of cost benefit of using these devices in the axillary surgery
Mean parameter model for the Pekar-Fr\"{o}hlich polaron in a multilayered heterostructure
The polaron energy and the effective mass are calculated for an electron
confined in a finite quantum well constructed of
layers. To simplify the study we suggest a model in which parameters of a
medium are averaged over the ground-state wave function. The rectangular and
the Rosen-Morse potential are used as examples.
To describe the confined electron properties explicitly to the second order
of perturbations in powers of the electron-phonon coupling constant we use the
exact energy-dependent Green function for the Rosen-Morse confining potential.
In the case of the rectangular potential, the sum over all intermediate virtual
states is calculated. The comparison is made with the often used leading term
approximation when only the ground-state is taken into account as a virtual
state. It is shown that the results are quite different, so the incorporation
of all virtual states and especially those of the continuous spectrum is
essential.
Our model reproduces the correct three-dimensional asymptotics at both small
and large widths. We obtained a rather monotonous behavior of the polaron
energy as a function of the confining potential width and found a peak of the
effective mass. The comparison is made with theoretical results by other
authors. We found that our model gives practically the same (or very close)
results as the explicit calculations for potential widths .Comment: 12 pages, LaTeX, including 5 PS-figures, subm. to Phys. Rev. B, new
data are discusse
Cortical functioning in children with developmental coordination disorder:a motor overflow study
This study examined brain activation in children with developmental coordination disorder (DCD) to reveal areas that may contribute to poor movement execution and/or abundant motor overflow. Using functional magnetic resonance imaging, 13 boys with DCD (mean age = 9.6 years ±0.8) and 13 typically developing controls (mean age = 9.3 years ±0.6) were scanned performing two tasks (finger sequencing and hand clenching) with their dominant hand, while a four-finger motion sensor recorded contralateral motor overflow on their non-dominant hand. Despite displaying increased motor overflow on both functional tasks during scanning, there were no obvious activation deficits in the DCD group to explain the abundant motor overflow seen. However, children with DCD were found to display decreased activation in the left superior frontal gyrus on the finger-sequencing task, an area which plays an integral role in executive and spatially oriented processing. Decreased activation was also seen in the left inferior frontal gyrus, an area typically active during the observation and imitation of hand movements. Finally, increased activation in the right postcentral gyrus was seen in children with DCD, which may reflect increased reliance on somatosensory information during the execution of complex fine motor tasks
Stereoselective handling of perhexiline:Implications regarding accumulation within the human myocardium
Purpose: Perhexiline is a prophylactic anti-ischaemic agent with weak calcium antagonist effect which has been increasingly utilised in the management of refractory angina. The metabolic clearance of perhexiline is modulated by CYP2D6 metaboliser status and stereoselectivity. The current study sought to (1) determine whether the acute accumulation of perhexiline in the myocardium is stereoselective and (2) investigate the relationship between duration of short-term therapy and the potential stereoselective effects of perhexiline within myocardium. Method: Patients (n = 129) from the active arm of a randomised controlled trial of preoperative perhexiline in cardiac surgery were treated with oral perhexiline for a median of 9 days. Correlates of atrial and ventricular concentrations of enantiomers were sought via univariate followed by multivariate analyses. Results: Myocardial uptake of both (+) and (−) perhexiline was greater in ventricles than in atria, and there was more rapid clearance of (−) than (+) perhexiline. The main determinants of atrial uptake of both (+) and (−) perhexiline were the plasma concentrations [(+) perhexiline: β = −0.256, p = 0.015; (−) perhexiline: β = −0.347, p = 0.001] and patients’ age [(+) perhexiline: β = 0.300, p = 0.004; (−) perhexiline: β = 0.288, p = 0.005]. Atrial uptake of (+) enantiomer also varied directly with duration of therapy (β = 0.228, p = 0.025), while atrial uptake of (−) perhexiline varied inversely with simultaneous heart rate (β = −0.240, p = 0.015). Conclusion: (1) Uptake of both perhexiline enantiomers into atrium is greater with advanced age and displays evidence of both saturability and minor stereoselectivity. (2) Atrial uptake of (−) perhexiline may selectively modulate heart rate reduction
The Anatomy of a Grid portal
In this paper we introduce a new way to deal with Grid portals referring to
our implementation. L-GRID is a light portal to access the EGEE/EGI Grid
infrastructure via Web, allowing users to submit their jobs from a common Web
browser in a few minutes, without any knowledge about the Grid infrastructure.
It provides the control over the complete lifecycle of a Grid Job, from its
submission and status monitoring, to the output retrieval. The system,
implemented as client-server architecture, is based on the Globus Grid
middleware. The client side application is based on a java applet; the server
relies on a Globus User Interface. There is no need of user registration on the
server side, and the user needs only his own X.509 personal certificate. The
system is user-friendly, secure (it uses SSL protocol, mechanism for dynamic
delegation and identity creation in public key infrastructures), highly
customizable, open source, and easy to install. The X.509 personal certificate
does not get out from the local machine. It allows to reduce the time spent for
the job submission, granting at the same time a higher efficiency and a better
security level in proxy delegation and management.Comment: 6 page
Importance of Polaronic Effects for Charge Transport in CdSe Quantum Dot Solids
We developed an accurate model accounting for electron-phonon interaction in colloidal
quantum dot supercrystals that allowed us to identify the nature of charge carriers and the
electrical transport regime. We find that in experimentally analyzed CdSe nanocrystal solids the electron-phonon interaction is sufficiently strong that small polarons localized to single dots are formed. Charge-carrier transport occurs by small polaron hopping between the dots, with mobility that decreases with increasing temperature. While such a temperature dependence of mobility is usually considered as a proof of band transport, we show that the same type of dependence occurs in the system where transport is dominated by small polaron hopping
Hematologic toxicity of radium-223 in elderly patients with metastatic Castration Resistant Prostate Cancer: a real-life experience
Background: Treatment with radium-223 has been shown to increase survival and to delay skeletal events related to bone metastases of patients with metastatic Castration Resistant Prostate Cancer (mCRPC). This treatment has also proved to be well tolerated, and hematological toxicity, in particular anemia, represents the most represented adverse event. Materials and methods: We evaluated the hematologic toxicity of Ra-223 treatment in a real-life experience of 38 patients from two Italian cancer centers, with bone metastases from mCRPC. The main endpoint of the study was the evaluation of the efficacy and tolerability of treatment with radium-223, with greater reference to hematological toxicity (especially anemia) as the cause of interruption of treatment, specifically in the elderly patient. Results: From August 2016 to October 2017, a total of 38 consecutive nonselected patients, 20 of them aged >75 years, with mCRPC symptomatic bone metastases, were enrolled for radium-223 at standard doses. Hematologic adverse events were recorded more frequently (72.4% with AE), and 36.8% had anemia. The most frequent cause of treatment discontinuation due to AEs was anemia [8/10 patients (80%)], followed by thrombocytopenia (2 patients) and neutropenia (1 patient). Hematologic AEs were more represented in elderly patients with greater disease burden and previously treated with docetaxel. Conclusions: Anemia is the most represented AE related to radium-223 treatment in elderly patients with greater disease burden and previously treated with docetaxel, besides representing the main reason for interruption of treatment. Correct patient selection, appropriate timing, and adequate supportive care are elements that could facilitate successful treatment with radium-223, preventing premature interruption of the same. The results of this experience support the opportunity to propose treatment with radium-223 mostly in patients in the earliest stages
Role of air pollutants mediated oxidative stress in respiratory diseases
Airborne particulate (PM) components from fossil fuel combustion can induce oxidative stress initiated by reactive oxygen species (ROS) that are strongly correlated with airway inflammation and asthma. A valid biomarker of airway inflammation is fractionated exhaled nitric oxide (FENO). The oxidative potential of PM2.5 can be evaluated with the dithiothreitol (DTT) dosage, which represents both ROS chemically produced and intracellular ROS of macrophages. This correlates with quality indicators of the internal environment and ventilation strategies such as dilution and removal of airborne contaminants
Optimized controllers for stabilizing the frequency changes in hybrid wind-photovoltaic-wave energy-based maritime microgrid systems
Reducing the dependence on traditional energy sources and shifting towards the utilization of renewable energy sources (RES) of energy in the maritime sector is imperative for reducing greenhouse gas emissions. Inherently, RES sources like solar and wind are intermittent and variable, resulting in inconsistent power availability and hence leading to energy supply fluctuations and potential shortages. In this respect, an efficient control strategy to maintain system stability and address intermittency effectively is essential. This work considers a hybrid marine microgrid with various energy sources like photovoltaics (PV), wind energy conversion system (WECS), marine biodiesel generator, Archimedes wave power generation, solid oxide fuel cell, and batteries. A 2-degree of freedom (2DOF) structure is designed and implemented with the tilt-integral-derivative filter (TIDN) to address frequency variations. Furthermore, an Archimedes optimization algorithm (AOA) is used to optimize the 2DOF-TIDN controller. The stability of the proposed microgrid system is assessed under various combinations of RES availabilities, including real-time data from WECS and PV. The AOA-based 2DOF-TIDN performance is compared to the following algorithms: genetic, Jaya, bat, grasshopper optimization, particle swarm optimization, and moth flame optimization. Simulation results obtained show that the AOA-based 2DOF-TIDN control strategy achieves shorter settling times in mitigating the changes of marine microgrid systems under different dynamic conditions as compared to the other algorithms. Finally, the controller being proposed in this paper was tested for robustness with parameter deviations of +25%, −20%, and − 40% from the nominal values, and proved to be the proposed 2DOF-TIDN controller parameters demonstrate significant robustness in effectively managing the uncertainties and parametric variations
- …
