Nanofluid with Colloidal Magnetic Fe3O4 Nanoparticles and Its Applications in Electrical Engineering

In this study, we propose a new type of a cooling agent based on magnetic nanofluid for the purpose of replacing the classical cooling fluids in electrical power transformers. The magnetite (Fe3O4) nanoparticles were synthesized by the co-precipitation method from an aqueous medium of salts FeCl3x6H2O and FeSO4x7H2O in the molar ratio Fe3+/Fe2+ = 2:1, by alkalization with 10% aqueous solution of NaOH at 80°C, for 1 h. The size of the magnetite nanoparticles, as measured by X-ray diffraction method, was 14 nm and by scanning electron microscopy (SEM), they are between 10 and 30 nm. Magnetite powder was placed in oleic acid as a surfactant to prevent agglomeration of nanoparticles. The resulting mixture was dispersed in transformer oil UTR 40, with the role of carrier liquid. The magnetic, rheological, thermal and electrical characteristic properties of the obtained Fe3O4 transformer oil-based nanofluid were determined. A mathematical model and numerical simulation results are very useful for investigating the heat transfer performances of the magnetic nanofluid. Based on this study, it was tested the cooling performance of this magnetic nanofluid for two types of electrical power transformers as compared to classical methods. We also presented a microactuator based on the same magnetic nanofluid

Online Buyer's Perspective of E-Shops Credibility: Measurement Dimensions

Addressing the debated topic of credibility in online sales, the present study analyses buyer's perspective. The study develops from the literature to test and refine a multi-dimensional measurement of e-shops credibility. Consumer's criteria for assessing e-shops credibility are empirically examined with 817 Romanian student participants. Detailed approach and methodology, as well as the results obtained, research conclusions, limitations, and implications, are presented. The study advances an instrument which reveals new dimensions of establishing credibility although most aspects were found to be similar to results previously presented in other studies. The proposed instrument offers a new multidimensional measurement and knowledge resources for business committed to using Internet advantages, and it might be viewed as a strategic tool which enables e-shops owners to strengthen their market presence, e-sales and customer base through an adequate management of the knowledge regarding online credibility

New oral anticoagulants and their reversal agents

Atrial fibrillation is a commonly encountered pathology in medical practice, and its prevalence has shown a continuous rise over the past years. Atrial fibrillation has a significant impact on patients\u27 quality of life, not only due to the standard anticoagulant treatment with vitamin K antagonists that require close monitoring and dose adjustment, but also due to the fragile equilibrium between hemorrhagic and thrombotic risks. The introduction of new oral anticoagulants (NOACs) in the treatment guidelines for atrial fibrillation has improved the quality of life, as NOACs do not require close monitoring or dose adjustments. However, even if the safety profile of the NOACs regarding the hemorrhagic risk is superior to vitamin K antagonists, the problem raised by an unexpected hemorrhage (e.g. severe hemorrhage after an accident) and the need for efficient hemostasis in a chronic anticoagulated patient has remained unsolved. To find a solution for this problem, reversal agents for NOACs have been developed and tested, and two of them, idarucizumab and andexanet-alpha, have already been approved by the FDA, thus making NOACs increasingly appealing as a choice of anticoagulation treatment

The impact of the COVID-19 pandemic on thyroid nodular disease: a retrospective study in a single center in the western part of Romania

IntroductionThe COVID-19 pandemic had a significant impact on the healthcare system, leading to a prioritization of hospital admissions in many countries. Romania was no exception, and it had to restrict patient access to medical services in hospitals with chronic diseases and oncological pathology, including thyroid cancer. This study aimed to compare the clinical and pathological factors of patients with nodular thyroid disease diagnosed and surgically treated during the two years before and after the COVID-19 pandemic, in a single medical institution.MethodsThe retrospective study included 1505 patients who were diagnosed and operated on for nodular thyroid disease between January 2018 and December 2021. The patients were divided into two groups: the “PRECOVID” group (January 2018 to February 2020), and the “POSTCOVID” group (March 2020 to December 2021). The analyzed parameters included patients’ gender, age, preoperative diagnosis, type of surgical intervention, and pathological diagnosis.ResultsA significant decrease was observed in the number of surgeries performed for thyroid nodular disease during the COVID-19 pandemic period (450 versus 1055 cases, p<0.00001). There was a significant decrease in the number of surgical reinterventions (0.9% in the POSTCOVID group versus 2.9% in the PRECOVID group, p=0.01) and a significant increase in the number of total thyroidectomies (84.9% in the POSTCOVID group versus 80.1% in the PRECOVID group, p=0.02). We also observed a higher incidence of malignant/borderline tumors in the POSTCOVID group compared to the PRECOVID group (p=0.04) and a significantly higher frequency of aggressive forms of thyroid cancer in the POSTCOVID group (p=0.0006).DiscussionThe COVID-19 pandemic had a significant impact on the surgical management of nodular thyroid disease, resulting in a decrease in surgeries and a change in the type of surgical interventions performed. The higher incidence of malignant/borderline tumors diagnosed during the pandemic highlights the importance of timely diagnosis and treatment of thyroid nodules to prevent cancer progression

Differentiating thyroid nodules parathyroid lesions using 2D-shear-wave elastography: a novel approach for enhanced diagnostic accuracy

Differentiating between thyroid and parathyroid lesions by means of ultrasound can be a challenge in some cases. This study explores the diagnostic efficacy of bidimensional shear wave elastography planewave ultrasound (2D SWE PLUS) as an auxiliary technique in distinguishing these superficial structures. We evaluated 86 cases, presenting with concurrent thyroid nodules and hyperparathyroidism, through conventional ultrasound and 2D SWE PLUS, employing an Aixplorer Supersonic Mach30 with a 5-18 MHz linear probe. Statistically significant differences were observed for the elasticity index (EI) between parathyroid and normal thyroid tissue (p<0.0001, U=291), and between parathyroid lesions and thyroid nodules (p<0.0001, U=248.5). An area under the curve (AUC) of 0.961, with an optimal cut-off value of ≤8.9 kPa, was established to effectively distinguish parathyroid tissue from normal thyroid tissue (sensitivity of 91.9%; specificity of 97.5%). Furthermore, an AUC of 0.963 and an optimal cut-off of 9.24 kPa (sensitivity of 94.2%, specificity of 91.1%) were determined for parathyroid vs thyroid lesions. Elasticity values were significantly elevated in the cancer group compared to benign thyroid nodules (p<0.0001). Our findings suggest that 2D SWE PLUS is an effective tool in differentiating between thyroid nodules and parathyroid lesions, enhancing diagnostic performance in neck ultrasonography

New oral anticoagulants and their reversal agents

Atrial fibrillation is a commonly encountered pathology in medical practice, and its prevalence has shown a continuous rise over the past years. Atrial fibrillation has a significant impact on patients\u27 quality of life, not only due to the standard anticoagulant treatment with vitamin K antagonists that require close monitoring and dose adjustment, but also due to the fragile equilibrium between hemorrhagic and thrombotic risks. The introduction of new oral anticoagulants (NOACs) in the treatment guidelines for atrial fibrillation has improved the quality of life, as NOACs do not require close monitoring or dose adjustments. However, even if the safety profile of the NOACs regarding the hemorrhagic risk is superior to vitamin K antagonists, the problem raised by an unexpected hemorrhage (e.g. severe hemorrhage after an accident) and the need for efficient hemostasis in a chronic anticoagulated patient has remained unsolved. To find a solution for this problem, reversal agents for NOACs have been developed and tested, and two of them, idarucizumab and andexanet-alpha, have already been approved by the FDA, thus making NOACs increasingly appealing as a choice of anticoagulation treatment

New oral anticoagulants and their reversal agents

Atrial fibrillation is a commonly encountered pathology in medical practice, and its prevalence has shown a continuous rise over the past years. Atrial fibrillation has a significant impact on patients' quality of life, not only due to the standard anticoagulant treatment with vitamin K antagonists that require close monitoring and dose adjustment, but also due to the fragile equilibrium between hemorrhagic and thrombotic risks. The introduction of new oral anticoagulants (NOACs) in the treatment guidelines for atrial fibrillation has improved the quality of life, as NOACs do not require close monitoring or dose adjustments. However, even if the safety profile of the NOACs regarding the hemorrhagic risk is superior to vitamin K antagonists, the problem raised by an unexpected hemorrhage (e.g. severe hemorrhage after an accident) and the need for efficient hemostasis in a chronic anticoagulated patient has remained unsolved. To find a solution for this problem, reversal agents for NOACs have been developed and tested, and two of them, idarucizumab and andexanet-alpha, have already been approved by the FDA, thus making NOACs increasingly appealing as a choice of anticoagulation treatment

Comparative Studies on the Administrative Convergence Revealed by National Strategies of Administrative Reform in Some South-Eastern European States

The paper has as main topic the administrative convergence and its reflection in the national strategies of administrative reform in some states in South Eastern Europe. Having a complex content, sometimes even ambiguous, the administrative convergence will have as finality the integration in the European Administrative Space and the administrative reforms as support. From this prospect, the South-Eastern Europe has a certain specificity emphasised by: - Different positions of the states under discussion related to the dynamics of the European integration process. - Development and evolution of the national public administrations in in direct connection both with Central European states and with the Eastern European ones, dominated by the Slav administrative culture, as well as the South European countries under the Balkan and Middle East influences. - Geo-strategic position of most states, including Romania, position that provides them a role of catalyser in the process of construction of the European Administrative Space. The paper is structured in three parts referring to the theoretical aspects concerning the administrative convergence, relevant case studies regarding Greece, Slovakia, Bulgaria and Romania, as well as conclusions based both on the theoretical elements and on the social perception of the domestic processes within the European Administrative Space. In the current version, the paper represents a research report drawn up within the framework of the Jean Monnet project “South-Eastern European developments on the administrative convergence and enlargement of the European Administrative Space in Balkan states

CREDIBILITY OF WEBSITES THROUGH FACETS AND DIMENSIONS

This study aims to investigate important aspects to concern on when building a commercial presentation website, in order to increase the credibility of the certain categories of a presentation website. Factor analysis was used in order to identify the dimensions of each category. The categories and resulted dimensions discussed were: “image” – with the following dimensions: Projected image, Specialist, Advert and Coherence, “relationship” – with the following dimensions: Bi-directional communication and Contact information, “product presentation” – with the following dimensions: In-depth description and Variety and “site functionality” – with the following dimensions: Usefulness, Official relationship, Complete communication, Exterior communication, Information format and References