Magnetostatic bias in multilayer microwires: theory and experiments

The hysteresis curves of multilayer microwires consisting of a soft magnetic nucleus, intermediate non-magnetic layers, and an external hard magnetic layer are investigated. The magnetostatic interaction between magnetic layers is proved to give rise to an antiferromagnetic-like coupling resulting in a magnetostatic bias in the hysteresis curves of the soft nucleus. This magnetostatic biasing effect is investigated in terms of the microwire geometry. The experimental results are interpreted considering an analytical model taking into account the magnetostatic interaction between the magnetic layers.Comment: 6 pages, 7 figure

Current applications of 3d printing in neurosurgery

Medical implications of 3-dimensional (3D) printing technology have progressed with increasingly used especially in surgical fields. 3D printing techniques are practical and anatomically accurate methods of producing patient specific models for medical education, surgical planning, training and simulation, and implants production for the assessment and treatment of neurosurgical diseases. This article presents the main directions of 3D printing models application in neurosurgery

Preliminary study of thrombogenicity induced by the nanoparticle surface coating of intracranial stents

Endovascular treatment of intracranial aneurysms with intracranial stents was proven to be clinically safe and effective, but is still associated with a risk of thromboembolic complications. Stent thrombosis could be a sever complication associated with specific stent surface coatings and designs. Standardized in vitro tests for investigation of thrombogenicity induced by different nanomaterials were used as the basic method in carrying out the present study. Therefore, the aim of this study was to evaluate the thrombogenicity of three different nanomaterials (ZnO, TiO2 si Fe3O4) possible used as surface coating for intracranial stents. This study is based on a procedure for in vitro analyses of plasma coagulation time. To measure the plasma coagulation time, platelet-poor plasma from human whole blood was in vitro exposed to nanoparticles and analysed in prothrombin (PT) and activated partial thromboplastin (APTT)

‘The International Teacher Leadership project,’ a case of international action research.

Copyright CARNThe paper arises from the International Teacher Leadership project, a research and development project involving researchers and practitioners in 14 European countries. The paper provides a conceptual exploration of the idea of teacher leadership and its role in educational reform, central to which is the idea that teachers, regardless of their level of power and organisational position, can engage in the leadership of enquiry-based development activity aimed at influencing their colleagues and embedding improved practices in their schools. The paper provides an outline of the project’s methodology which builds on that used in the Carpe Vitam Leadership for Learning project (Frost, 2008a). It is a form of collaborative action research which is highly developmental and discursive. It seeks to identify principles, strategies and tools that can be applied in a range of cultural settings. The paper includes a thematic analysis of the cultural contexts and policy environments of the participating countries in order to identify the obstacles to teacher leadership and to inform the nature of the support strategies employed

Discovery of biological networks from diverse functional genomic data

We have developed a general probabilistic system for query-based discovery of pathway-specific networks through integration of diverse genome-wide data. This framework was validated by accurately recovering known networks for 31 biological processes in Saccharomyces cerevisiae and experimentally verifying predictions for the process of chromosomal segregation. Our system, bioPIXIE, a public, comprehensive system for integration, analysis, and visualization of biological network predictions for S. cerevisiae, is freely accessible over the worldwide web

Pathological elongation of the internal carotid artery: surgical treatment and immediate postoperative results

Scopul lucrării. În structura cauzelor dezvoltării insuficienței cerebrovasculare, elongarea patologică a arterei carotide interne ocupă locul 2, după afectarea aterosclerotică. Prevalența dolicoarteriopatiei la populația generală se estimează a fi de la 10 la 40 %, iar de la 16% până la 56 % din pacienți au în anamnestic deficit neurologic tranzitor sau permanent. Scopul lucrării este optimizarea tehnicilor chirurgicale și aprecierea eficienței postoperatorii imediate la pacienții cu elongare patologică a arterei carotide interne. Materiale și metode. Studiul efectuat reprezintă o analiză retrospectivă a 243 pacienți, tratați în cadrul IMSP SCR ,,Timofei Moșneaga”, secția de Chirurgie Vasculară în perioada 2002-2022. Rezultate. La pacienții supuși studiului s-a efectuat 258 intervenții chirurgicale. Rezultatele imediate au fost: la 230 pacienți (89.14 %) a dispărut simptomatologia preoperatorie, AVC ischemic s-a înregistrat la 1 pacient, sindrom coronarian acut sau deces nu s-a înregistrat la nici un pacient din lotul studiat. Concluzii. Luând în considerare rata mică de complicații periprocedurale precum și eficacitatea postoperatorie imediată evidentă, putem spune că intervenția chirurgicală în tratamentul elongărilor patologice ale arterelor carotide interne reprezintă o metoda sigură și eficientă pentru prevenirea accidentelor vasculare cerebrale acute și îmbunătățirea calității vieții pacienților.Aim of study. Among the causes contributing to the development of cerebrovascular insufficiency, pathological elongation of the internal carotid artery ranks second after atherosclerotic involvement. The prevalence of dolichoarteriopathy in the general population is estimated to range from 10% to 40%, and between 16% and 56% of patients have a history of transient or permanent neurological deficits. The aim of this study was to optimize surgical techniques and assess immediate postoperative efficacy in patients with pathological elongation of the internal carotid artery. Materials and methods. This study represents a retrospective analysis of 243 patients treated at the State Medical and Pharmaceutical University "Timofei Moșneaga", Department of Vascular Surgery, between 2002 and 2022. Results. A total of 258 surgical interventions were performed in the study group. The immediate results were as follows: symptomatology disappeared in 230 patients (89.14%), one patient experienced an ischemic stroke, and no cases of acute coronary syndrome or death were recorded among the studied patients. Conclusions. Considering the low rate of periprocedural complications and the evident immediate postoperative effectiveness, it can be concluded that surgical intervention for the treatment of pathological elongation of the internal carotid artery is a safe and efficient method for preventing acute cerebrovascular accidents and improving the quality of life for patients

Introducing Semi-Interpenetrating Networks of Chitosan and Ammonium-Quaternary Polymers for the Effective Removal of Waterborne Pathogens from Wastewaters

The present work aims to study the influence of ammonium-quaternary monomers and chitosan, obtained from different sources, upon the effect of semi-interpenetrating polymer network (semi-IPN) hydrogels upon the removal of waterborne pathogens and bacteria from wastewater. To this end, the study was focused on using vinyl benzyl trimethylammonium chloride (VBTAC), a water-soluble monomer with known antibacterial properties, and mineral-enriched chitosan extracted from shrimp shells, to prepare the semi-IPNs. By using chitosan, which still contains the native minerals (mainly calcium carbonate), the study intends to justify that the stability and efficiency of the semi-IPN bactericidal devices can be modified and better improved. The new semi-IPNs were characterized for composition, thermal stability and morphology using well-known methods. Swelling degree (SD%) and the bactericidal effect assessed using molecular methods revealed that hydrogels made of chitosan derived from shrimp shell demonstrated the most competitive and promising potential for wastewater (WW) treatment.Introducing Semi-Interpenetrating Networks of Chitosan and Ammonium-Quaternary Polymers for the Effective Removal of Waterborne Pathogens from WastewaterspublishedVersio

Reliable protocol for sample preparation to observe nanomaterial adherence to the surface of biological cells by using scanning electron microscopy

Background. When assessing the interaction between nanomaterials and cells, an important step is to image the effects induced by the material to the cell membrane. In order to evaluate the results of the interaction process, scanning electron microscopy (SEM) is typically used. Commonly, an important step during the preparation of biological cell samples for SEM is represented by the critical point drying, which involves the replacement of the alcohol used for dehydration with an inert gas. This conventional drying method is not only hard to accomplish, but it can lead to sample destruction if specific parameters are not met. On the other hand, when assessing nanomaterials adhered to the cell membrane, the integrity of the cell is not necessarily important, so a little cell deflation doesn’t affect the intended purpose of the evaluation. Here, we describe a simple and more cost efficient method to prepare biological samples for SEM imaging that preserves cell integrity and can be used to describe nanomaterials interaction with cell surface. Methods. Cells were grown on sterilized silica chips, after which the evaluated nanomaterial was added to the cell culture media at least 24h for incubation. Afterwards, the samples were washed to eliminate non-adhered nanomaterials, fixed with glutaraldehyde and osmium tetroxide, and dehydrated with increasing concentrations of alcohol. The silica chips were then air dried in the biological safety hood and in vacuum, followed by a sputter coat film of 5 nm of gold. The samples were imaged with a scanning electron microscope. Results. We were able to obtain well preserved biological cell samples, both with and without nanomaterials adhered to the cell membrane surface. Nanomaterials such as magnetic nanoparticles and magnetic nanowires were easily traceable on cell surface. Furthermore, the nanomaterials were clearly observed in the images obtained, while the cell surface was not affected by the drying process applied. Although the samples obtained using our method were characterized by a slight deflation of the cells, the morphology of the cells is well preserved and the method is suitable for the evaluation of the interaction between nanomaterials and cell surfaces. Conclusions: We have described a novel cost efficient and easy to perform method for processing biological samples for SEM imaging that preserves cell morphology and can be used for analyzing nanoparticle and nanowires interaction with cell surface

Carotid-brachial bypass in severe upper limb ischemia

Scopul lucrării. În ocluziile axului arterial subclavio-axilar cu ischemie severă a membrului superior s-ar impune folosirea metodelor endovasculare sau aplicarea unui bypass ortotop. În cazul imposibilității din motive tehnice sau stării pacientului drept alternativă servește bypass-ul carotido-brahial. Scopul studiului este aprecierea posibilității utilizării bypass-ului extraanatomic carotido-brahial în revascularizarea membrului superior în ischemia severă. Materiale și metode. Studiul cuprinde 5 pacienți cu ocluzia axului subclavio-axilar cu ischemie severă a membrului superior, dintre care 3 cu ocluzie acută pe fondal de stenoze aterosclerotice, la care intervenția inițială de trombectomie (embolectomie) a eșuat, un pacient cu tromboza anevrismului a. subclaviculare și un pacient cu ocluzie aterosclerotică de gradul IV cu gangrena degetului II, la care intervenția endovasculară a eșuat. La toți pacienții s-a aplicat un bypass carotido-brahial cu grefon safen intern inversat. Grefele au fost amplasate suprafascial supraclavicular. Rezultate. La toți 5 pacienți ischemia a cedat complet. La 4 din ei s-a restabilit pulsul distal. La pacientul cu ateroscleroză cronică de gradul IV, cu afectarea concomitentă a arterelor antebrațului, pulsul s-a restabilit la bifurcația arterei brahiale. La acest pacient s-a efectuat amputația degetului. Complicații nu s-au înregistrat. Incomodități subiective din cauza amplasării suprafasciale și supraclaviculare a bypass-urilor deasemenea n-au fost înregistrate. Concluzii. Bypass-urile carotido-brahiale localizate suprafascial și supraclavicular servesc o alternativă a bypass-urilor ortotope inclusiv în cazurile eșecurilor sau contraindicațiilor metodelor endovasculare.Aim of study. In cases of occlusion of the subclavian-axillary arterial axis with severe upper limb ischemia, the use of endovascular methods or the application of an orthotopic bypass may be necessary. In case of technical impossibility or patient condition, carotidbrachial bypass serves as an alternative. The objective of the study is to evaluate the possibility of using extra-anatomic carotidbrachial bypass for revascularization of the upper limb in severe ischemia Materials and methods. The study includes 5 patients with occlusion of the subclavian-axillary axis and severe upper limb ischemia, of which 3 had acute occlusion due to atherosclerotic stenosis, with initial thrombectomy (embolectomy) being unsuccessful. One patient had subclavian artery aneurysm thrombosis, and one patient had grade IV atherosclerotic occlusion with gangrene of the second digit, in whom endovascular intervention was unsuccessful. Carotid-brachial bypass with an inverted internal saphenous vein graft was performed in all patients. The grafts were placed in a suprafascial supraclavicular position. Results. Complete resolution of ischemia was achieved in all 5 patients. Distal pulses were restored in 4 of them. In the patient with chronic grade IV atherosclerosis and concomitant involvement of the forearm arteries, the pulse was restored at the brachial artery bifurcation. Digit amputation was performed in this patient. No complications were recorded, and there were no subjective discomforts related to the suprafascial and supraclavicular placement of the bypasses. Conclusions. Suprafascial and supraclavicular carotid-brachial bypasses serve as an alternative to orthotopic bypasses, including in cases of failure or contraindications to endovascular methods