24 research outputs found
Analysis of the hyperthermia efficiency and MRI quality trade off in PMMA-based bone cements loaded with magnetic nanoparticles
No full textSummary form only given. In this work, T 1 -weighted images (MP-RAGE sequence) of cylindrical PMMA mixed with MNP (PMMA-MNP) samples have been carried out in agar gel phantoms with a Siemens 3T MR scanner. Two types of MNP were tested (iron oxide powder and ferrofluid suspension) with different concentrations. For every MRI session, 21 slices were selected centralized around the half length of the sample. The artifact caused by the magnetic nanoparticles was measured in each slice by fitting an ellipse to the disturbed area and subtracting the radius of the sample from the average of the major and minor ellipse radii. As a tool for the fitting, the images were masked with a threshold of 30% of their maximal value. Since each phantom was measured twice, this procedure led to a total of 42 values, indicating the spread of the artifact, for each MNP concentration. Boxplots of the measured artifact as function of MNP concentrations were depicted. Ferrofluid samples give rise to lower MRI artifacts compared to samples prepared with the iron oxide powder and having the same MNP concentration. Moreover, the values vary less between the slices for ferrofluid samples as can be seen by smaller interquartile ranges. Results demonstrate that both concentration and type of MNP affect the MRI behavior of PMMA-MNP samples. In this study, we provide a balance of the needed MNP concentration to have an efficient magnetic hyperthermia treatment with minimum artifact for the required quality of MRI in case of PMMA-based bone cements loaded with MNP
Machine learning-based prediction of toxic metals concentration in an acid mine drainage environment, northern Tunisia
No full textIn northern Tunisia, Sidi Driss sulfide ore valorization had produced a large waste amount. The long tailings exposure period and in situ minerals interactions produced an acid mine drainage (AMD) which contributed to a strong increase in the mobility and migration of huge heavy metal (HM) quantities to the surrounding soils. In this work, the soil mineral proportions, grain sizes, physicochemical properties, SO42− and S contents, and Machine Learning (ML) algorithms such as the Random Forest (RF), Support Vector Machine (SVM), and Artificial Neural Network (ANN) models were used to predict the soil HM quantities transferred from Sidi-Driss mine drainage to surrounding soils. The results showed that the HM concentrations had significantly increased with the increase of decomposition and oxidation of galena, marcasite, pyrite, and sphalerite-marcasite and Fe-oxide-hydroxides quantities and the sulfate dissolution (marked with SO42− ions increase) that produced the decreased soil pH. Compared to SVM, and ANN models outputs, the RF model that revealed higher R2val, RPD, RPIQ, and lower error indices had satisfactorily predicted the soil HM accumulation coming from the AMD environment. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature
Experimental ex-vivo validation of PMMA-based bone cements loaded with magnetic nanoparticles enabling hyperthermia of metastatic bone tumors
No full textPercutaneous vertebroplasty comprises the injection of Polymethylmethacrylate (PMMA) bone cement into vertebrae and can be used for the treatment of compression fractures of vertebrae. Metastatic bone tumors can cause such compression fractures but are not treated when injecting PMMA-based bone cement. Hyperthermia of tumors can on the other hand be attained by placing magnetic nanoparticles (MNPs) in an alternating magnetic field (AMF). Loading the PMMA-based bone cement with MNPs could both serve vertebra stabilization and metastatic bone tumor hyperthermia when subjecting this PMMA-MNP to an AMF. A dedicated pancake coil is designed with a self-inductance of 10 mu H in series with a capacitance of 0.1 mu F that acts as resonant inductor-capacitor circuit to generate the AMF. The thermal rise is appraised in beef vertebra placed at 10 cm from the AMF generating circuit using optical temperatures sensors, i. e. in the center of thePMMA-MNPbone cement, which is located in the vicinity of metastatic bone tumors in clinical applications; and in the spine, which needs to be safeguarded to high temperature exposures. Results show a temperature rise of about 7 degrees C in PMMA-MNP whereas the temperature rise in the spine remains limited to 1 degrees C. Moreover, multicycles heating of PMMA-MNP is experimentally verified, validating the technical feasibility of having PMMA-MNP as basic component for percutaneous vertebroplasty combined with hyperthermia treatment of metastatic bone tumors
SRC_Num_TDOA: Multiple speech sources’ number and their TDOA Estimation from a stereo recorded mixture
No full textAbstractWe consider the problem of sources counting and Time Delays of Arrival (TDOAs) estimation from a two-channel reverberant mixture in the underdetermined case. Most existing estimating TDOA implementations are based on a prior knowledge about the number of involved sources in the mixture. Whereas, we develop a new function that only takes the observed mixtures as input. In this paper, we describe the basic of the proposed function, its development and its evaluation on real recorded mixtures with reference to widely used methods. Through simulations and real environment experiments, we indicate that our method outperforms other state-of-the-art TDOA methods in terms of accuracy, while being significantly more efficient in terms of computational complexity
The effect of the magnetic nanoparticle’s size dependence of the relaxation time constant on the specific loss power of magnetic nanoparticle hyperthermia
No full text
The effect of the magnetic nanoparticles size dependence of the relaxation time constant on the specific loss power of magnetic nanoparticle hyperthermia
No full textReducing the prevalence of compassion fatigue in emergency department nurses through resilience training
No full textCompassion fatigue is exhaustion that limits the ability of caring relationships. Emergency department nurses deal with high stress situations that involve physical and emotional challenges that may result in compassion fatigue. Due to the challenges of the demands faced by emergency department nurses, compassion fatigue is a vast issue, which impacts the quality of care provided. Compassion fatigue affects patient satisfaction and staff turnover, ultimately leading to the nursing shortage. Therefore, it is a problem worth investigating and working to resolve.
Methodology: Resilience techniques such as self-care strategies (i.e, sleep, adequate hydration and nutrition) as well as guided meditation and self-affirmation were discussed in a one-hour resilience training to help emergency department nurses in a level two trauma hospital develop resiliency techniques to overcome compassion fatigue. Compassion fatigue was scored on a Professional Quality of Life tool developed by Hudnall Stamm (2009) before and after the training to assess the effectiveness of the training on emergency department nurses.
Results: A Mann Whitney U statistical analysis showed statistically significant results for the subsets of burnout, compassion satisfaction, and secondary traumatic stress (p = .000). The mean scores for each subset of the Professional Quality of Life tool have also improved post-intervention.
Conclusion: The results of this project correlate with evidence in the literature, stating that resiliency training works to improve compassion fatigue by improving compassion satisfaction and decreasing burnout and secondary traumatic stress. The resilience training for this project used strategies that include self-care, mentoring, and exercise, which gave nurses different techniques to improve resiliency such as guided meditation and tips on improving their health and lifestyle. It was concluded that resilience training has a positive effect on reducing the prevalence of compassion fatigue in emergency department nurses.DNPIncludes bibliographical reference
