13 research outputs found
A comparative theoretical investigation of optoelectronic and mechanical properties of KYS2 and KLaS2
No full textThe ternary sulfides KYS2 and KLaS2 are two promising candidates for numerous applications, as much as white LED, X-ray phosphor and transparent conductor materials. However, theoretical studies on these materials are lacking, and many of their physical properties are still unknown. The aim of this work is to investigate the physical properties of the ternary sulfides KYS2 and KLaS2 namely, structural, elastic, optoelectronic, thermodynamic analysis, and set the substitution effect of Y and La elements in the two compounds. The fundamental properties calculations are based on ab-initio pseudopotential framework, with both local density approximation (LDA) and generalized gradient approximations (GGA) along with an expanded set of plane waves. The Becke, 3-parameter, Lee–Yang–Parr (B3LYP) hybrid functional is also employed to describe the electronic structures and optical properties. The optimized crystal parameters are correlated very well with the existing experimental data. The predicted values of the elastic constants demonstrate that the two compounds are mechanically stable and can be classified as brittle materials. The band structure analysis reveals that both KYS2 and KLaS2 have indirect band gap. The optical properties, like the refractive index, extinction, absorption and reflectivity coefficients, are determined for various polarizations of incident light, while both compounds present optical anisotropy. The obtained optical properties indicate the high transparency of KYS2 and KLaS2 in the infrared and visible regions, which makes them promising candidates for many of transparent applications. The thermodynamic properties are investigated with the help of quasiharmonic Debye model approximation. KYS2 has a larger bulk modulus value, which make it more beneficial in engineering applications. Calculations of thermodynamical properties indicate that KYS2 compound has better thermal conductivity, stronger chemical bonds and bigger hardness.</p
La chirurgie cardiaque mini-invasive vidéo-assistée : une étude comparative à la voie conventionnelle [Less-invasive video-assisted cardiac surgery : a comparative study with the conventional approach]
Get PDFFrench Abstract:
Introduction-La sternotomie médiane verticale a été la meilleure voie d’abord en chirurgie cardiaque. C’est une voie, traumatisante dotée de plusieurs complications. L’introduction de la caméra a réduit considérablement l’incision.
Matériels et méthodes -Dans notre étude, prospective et comparative, 57 patients ont subi une chirurgie cardiaque, répartis en 2 groupes, 30 patients opérés par sternotomie médiane verticale et 27 patients opérés par chirurgie mini-invasive vidéo-assistée. Les données préopératoires, opératoires et postopératoires ont été collectées et analysées.
Résultats - l’âge moyen est 49.5+16.3 ans dans le groupe mini-invasive vidéo-assistée et 43.4+16.7 dans le groupe sternotomie médiane verticale. Le signe le plus fréquent était la dyspnée. Les patients asymptomatiques représentent 11% dans le groupe sternotomie médiane verticale et 43% dans le groupe mini-invasive vidéo-assistée.La chirurgie de la valve mitrale dans 63% patients opérés par la mini-invasive vidéo-assistée et 66.6% par sternotomie médiane verticale. La moyenne du temps de la circulation extracorporelle était de119.52+44.5 min dans le groupe mini-invasive vidéo-assistée et 84.53+34.2 min dans l’autre groupe. La moyenne du clampage aortique dans le groupe mini-invasive vidéo-assistée était 94.56+40.8 min et dans le groupe sternotomie médiane verticale était
de 59.53+25.5 min. La moyenne de ventilation mécanique était de 4.7+1.8 heures dans le groupe mini-invasive vidéo-assistée et de 7.9±2.4 heures dans le groupe sternotomie médiane verticale. La douleur post-opératoire disparait dans (73%) des cas au 2ème jour postopératoire en mini-invasive vidéo-assistée et dans (70%) au 5ème jour en sternotomie médiance verticale. La moyenne de séjour hospitalier 8.67+3.8 jours en mini-invasive vidéo-assistée et de 13.8+5.0jours en sternotomie médiane verticale. La reprise des activités physiques était très précoce après une chirurgie mini-invasive.
Conclusion -la procédure mini-invasive vidéo-assistée est une alternative simple, sûre et efficace. D’excellents résultats sont obtenus avec une faible morbidité. Cette procédure offre une convalescence rapide.
English Abstract:
Background-Vertical median sternotomy has been the best approach to cardiac surgery. While the conventional approach is traumatic, with many complications, using a video camera in surgery offers smaller incisions.
Methods - Our study was a prospective and comparative one. Our sample consisted of 57 patients, divided into 2 groups, including 30 patients operated by vertical median sternomtomy and 27 patients operated by minimally invasive video-assisted surgery. Preoperative, operative and postoperative data were collected and analyzed.
Results -The patients’mean age was 49.5+16.3 years in the minimally invasive video-assisted group and 43.4+16.7 in the vertical median sternotomy group. The most common sign among these patients was dyspnea. Asymptomatic patients represented 11% in the vertical median sternotomy group and 43% in the minimally invasive video-assisted group. Mitral valve surgery was in 63% patients of minimally invasive video-assisted and 66.6% of vertical median sternotomy group. The mean time of cardiopulmonary bypass was 119.52+44.5 min in the minimally invasive video-assisted group and 84.53+34.2 min in the vertical median
sternotomy group. The mean time of aortic clamping in the minimally invasive video-assisted group was 94.56+40.8 min while it was 59.53+25.5 min in the vertical median sternotomy group. The mean time of mechanical ventilation was 4.7+1.8 hours in the minimally invasive video-assisted group and 7.9±2.4 hours in the vertical median sternotomy group. Postoperative pain disappeared on the 2nd postoperative day in (73%) of the minimally invasive video-assisted group cases and on the 5th day in (70%) of vertical median sternotomy group cases. The average hospital stay was 8.67+3.8 days in minimally invasive video-assisted and 13.8+5.0 days in vertical median sternotomy group. Faster recovery of physical activities after minimally invasive surgery was reported.
Conclusion - The minimally invasive video-assisted is a simpler, safer and more effective procedure with excellent results and low morbidity. This procedure results in a short -er recovery time
La chirurgie cardiaque mini-invasive vidéo-assistée : une étude comparative à la voie conventionnelle [Less-invasive video-assisted cardiac surgery : a comparative study with the conventional approach]
Get PDFFrench Abstract:
Introduction-La sternotomie médiane verticale a été la meilleure voie d’abord en chirurgie cardiaque. C’est une voie, traumatisante dotée de plusieurs complications. L’introduction de la caméra a réduit considérablement l’incision.
Matériels et méthodes -Dans notre étude, prospective et comparative, 57 patients ont subi une chirurgie cardiaque, répartis en 2 groupes, 30 patients opérés par sternotomie médiane verticale et 27 patients opérés par chirurgie mini-invasive vidéo-assistée. Les données préopératoires, opératoires et postopératoires ont été collectées et analysées.
Résultats - l’âge moyen est 49.5+16.3 ans dans le groupe mini-invasive vidéo-assistée et 43.4+16.7 dans le groupe sternotomie médiane verticale. Le signe le plus fréquent était la dyspnée. Les patients asymptomatiques représentent 11% dans le groupe sternotomie médiane verticale et 43% dans le groupe mini-invasive vidéo-assistée.La chirurgie de la valve mitrale dans 63% patients opérés par la mini-invasive vidéo-assistée et 66.6% par sternotomie médiane verticale. La moyenne du temps de la circulation extracorporelle était de119.52+44.5 min dans le groupe mini-invasive vidéo-assistée et 84.53+34.2 min dans l’autre groupe. La moyenne du clampage aortique dans le groupe mini-invasive vidéo-assistée était 94.56+40.8 min et dans le groupe sternotomie médiane verticale était
de 59.53+25.5 min. La moyenne de ventilation mécanique était de 4.7+1.8 heures dans le groupe mini-invasive vidéo-assistée et de 7.9±2.4 heures dans le groupe sternotomie médiane verticale. La douleur post-opératoire disparait dans (73%) des cas au 2ème jour postopératoire en mini-invasive vidéo-assistée et dans (70%) au 5ème jour en sternotomie médiance verticale. La moyenne de séjour hospitalier 8.67+3.8 jours en mini-invasive vidéo-assistée et de 13.8+5.0jours en sternotomie médiane verticale. La reprise des activités physiques était très précoce après une chirurgie mini-invasive.
Conclusion -la procédure mini-invasive vidéo-assistée est une alternative simple, sûre et efficace. D’excellents résultats sont obtenus avec une faible morbidité. Cette procédure offre une convalescence rapide.
English Abstract:
Background-Vertical median sternotomy has been the best approach to cardiac surgery. While the conventional approach is traumatic, with many complications, using a video camera in surgery offers smaller incisions.
Methods - Our study was a prospective and comparative one. Our sample consisted of 57 patients, divided into 2 groups, including 30 patients operated by vertical median sternomtomy and 27 patients operated by minimally invasive video-assisted surgery. Preoperative, operative and postoperative data were collected and analyzed.
Results -The patients’mean age was 49.5+16.3 years in the minimally invasive video-assisted group and 43.4+16.7 in the vertical median sternotomy group. The most common sign among these patients was dyspnea. Asymptomatic patients represented 11% in the vertical median sternotomy group and 43% in the minimally invasive video-assisted group. Mitral valve surgery was in 63% patients of minimally invasive video-assisted and 66.6% of vertical median sternotomy group. The mean time of cardiopulmonary bypass was 119.52+44.5 min in the minimally invasive video-assisted group and 84.53+34.2 min in the vertical median
sternotomy group. The mean time of aortic clamping in the minimally invasive video-assisted group was 94.56+40.8 min while it was 59.53+25.5 min in the vertical median sternotomy group. The mean time of mechanical ventilation was 4.7+1.8 hours in the minimally invasive video-assisted group and 7.9±2.4 hours in the vertical median sternotomy group. Postoperative pain disappeared on the 2nd postoperative day in (73%) of the minimally invasive video-assisted group cases and on the 5th day in (70%) of vertical median sternotomy group cases. The average hospital stay was 8.67+3.8 days in minimally invasive video-assisted and 13.8+5.0 days in vertical median sternotomy group. Faster recovery of physical activities after minimally invasive surgery was reported.
Conclusion - The minimally invasive video-assisted is a simpler, safer and more effective procedure with excellent results and low morbidity. This procedure results in a short -er recovery time
Microtubule-Associated Motor Proteins in Skeletal Development and Health
No full text\ua9 The Author(s), under exclusive license to Springer Nature Switzerland AG 2024. Extracellular changes resulting in perturbed skeletal development can be a direct result of mutations in the structural extracellular matrix (ECM) components and of changes in the receptor activity and signalling pathways, but also of perturbations to intracellular mechanisms that can have secondary extracellular consequences. The developing cartilage and bone are highly secretory and mechanoresponsive tissues, and the intracellular processes governed by the cytoskeletal proteins and by the associated molecular motors aid in protein processing and secretion, recycling of membrane-bound receptors, positioning of the organelles, maintenance of the primary cilia, modulation of signalling pathways, and coordination of the cell cycle. Molecular motors hydrolyse ATP to generate forces that allow them to travel towards either plus or minus ends of the microtubules generating forces that govern the movement of all intracellular cargo as well as the formation of the mitotic spindle and polar ejection forces during cell division. Their complex structure and diversity allow for varied cargo, from membrane-bound vesicles (lysosomes, endosomes, phagosomes, peroxisomes) to organelles (mitochondria, Golgi apparatus, nucleus), lipid droplets, chromosomes, and nucleic acids (DNA and mRNA). In this chapter, we discuss the microtubule-associated molecular motors, dyneins, and kinesins and their emerging roles in skeletal dysplasia
Exploring Heusler superconducting properties for Ni2ZrAl and Ni2ZrGa Heusler compounds: First principal insight
No full textThis paper presents a theoretical study of structural, mechanical, electronic, vibrational and superconducting properties of full Heusler compounds Ni2ZrZ (Z= Al and Ga) using the norm conserving pseudo potential within the framework of Density Functional Theory (DFT) and Density Functional Perturbation Theory (DFPT). Our finding reveal that the non-magnetic L21 phase structure is energetically more stable for both compounds. The band structure shows that these compounds have a metallic behavior with a saddle point (Van Hove Singularity) at L-point. Elastic and vibrational properties analysis confirm the mechanical and dynamical stability of our studied compounds. The Ni2ZrAl and Ni2ZrGa exhibit BCS weak coupling superconductivity with critical temperatures of 1.78 K and 2.68 K, respectively. The study extends to explore the impact of Hf concentrations, providing valuable insights into the superconducting properties of Ni2Zr(1-x)HfxGa alloys
The sequel of modified fly ashes using high energy ball milling on mechanical performance of substituted past cement
No full textInternational audienceThe consideration of planetary ball mill processing is attempted to obtain modified fly ashes powders that are used as substitutes in a cement paste. Ball milling conditions are related to structural modifications of processed powders. These modifications are retrieved from X-ray diffraction, infrared spectroscopy, powder granulometry, and scanning electron microscopy. As an industrial application, the milled fly ashes are substituted to two different cements to show possible effect on compressive strength of cement pastes. Structural analysis of milled fly ashes show loss of crystallinity of the magnetite phase, nanosizing trend of quartz and mullite phases with some straining that takes place after only 1 h of milling. The drop of particle size of the milled fly ashes is also evidenced but with tendency to agglomeration and particle shape modification from spherical to irregular forms.Mechanical performance results related to modified cement pastes indicate successful substitution of cements by milled fly ashes up to 50%. Substitution results in levels of compressive strength as large as 70 MPa for particular combination of milling time, fly ash content and curing time
Synthesis, Characterization, and Crystal Structure Determination of a New Lithium Zinc Iodate Polymorph LiZn(IO3)3
No full textInternational audienc
A Novel Multispectral Maritime Target classification based on ThermalGAN (RGB-to-Thermal Image Translation)
No full textConvolutional Neural Networks (CNN) for ship classification in multi-spectral images (RGB, IR, etc.) is proposed in this paper. Recent developments in deep learning have significantly advanced the field of ship recognition. However, since maritime light intensity is frequently disturbed, multispectral imaging is considered a more robust substitute for RGB imaging. The proposed architectures were fine-tuned after being trained from scratch on the publicly available dataset VAIS (RGB-IR pairs). Unfortunately, the classification results plateaued at 59.74% accuracy, which is unsatisfactory for most real-life applications. Such an accuracy wall was due to the small number of training images. In order to overcome the scarcity of IR ship images, we proposed a novel image data augmentation strategy that translates RGB images to IR. A Pix2Pix model and a Generative Adversarial Network (GAN) network were modified to carry out the generation process as an RGB to IR translator. The KAIST general-purpose RGB-IR image pairs dataset was used to train our RGB-to-IR image translator, whereas the VAIS dataset was held aside for validation purposes. Our proposed network improved the accuracy of the native network by 8% (from 59.74% to 67.74%), which is fairly satisfactory in the field of ship recognition.</p
