检索结果-南通市图书馆

physical-Chemical Characterization of Nanodispersed powders produced by a plasma-Chemical Technique

在线全文

学校读者我要写书评

暂无评论

plasma Science and Technology 2007年第3期9卷 273-279页

作者： M.georgieva G.VISSOKOV Iv.GRANCHAROV Department of Technology of Inorganic Substances University of Chemical Technology and Metallurgy8St.Kliment Ohridski Blvd.1756 SofiaBulgaria

This article presents a review on the physical-chemical properties and characteristics of plasma-chemically produced nanodispersed powders （NDp）, such as metals, oxides, nitrides, carbides, and catalysts. The plasma-chemical preparatior~ of the powders was carried out in thermal plasma （Tp） created by means of high-current electric arcs, plasma jets, high-frequency （HF） discharges, etc. We also discuss certain properties and characteristics of the NDps, which are determined largely by the conditions of preparation.

关键词： plasma-chemical treatment nitrides thermodynamic analysis

Detection of CO2 and O2 by iron loaded LTL zeolite films

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2018年第1期12卷 94-102页

作者： Veselina georgieva Richard Retoux Valerie Ruaux Valentin Valtchev Svetlana Mintova Laboratoire Catalyse et Spectrochimie (LCS) ENSICAEN CNRS Normandy University 14000 Caen France Laboratoire de Cristallographie et Sciences des Matériaux (CRISMAT) ENSICAEN CNRS Normandy University 14000 Caen France

Detection of oxygen and carbon dioxide is important in the field of chemical and biosensors for atmosphere and biosystem monitoring and fermentation processes. The present study reports on the preparation of zeolite films doped with iron nanoparticles for detection of CO2 and O2 in gas phase. pure nanosized LTL type zeolite with monomodal particle size distribution loaded with iron （Fe-LTL） was prepared under hydrothermal condition from colloidal precursor suspensions. The zeolite was loaded with iron to different levels by ion exchange. The Fe-LTL suspensions were used for preparation of thin films on silicon wafers via spin coating method. The reduction of the iron in the zeolite films was carried out under H2 flow （50% H2 in Ar） at 300 ℃. The presence of iron nanoparticles is proved by in situ ultra-violet-visible spectroscopy. The properties of the films including surface roughness, thickness, porosity, and mechanical stability were studied. In addition, the loading and distribution of iron in the zeolite films were investigated. The Fe-LTL zeolite films were used to detect O2 and CO2 in a concentration dependent mode, followed by IR spectroscopy. The changes in the IR bands at 855 and 642 cm^-1 （Fe O-H and Fe-O bending vibrations） and at 2363 and 2333 cm^-1 （CO2 asymmetric stretching） corresponding to the presence of O2 and CO2, respectively, were evaluated. The response to O2 and CO2 was instant, which was attributed to great accessibility of the iron in the nanosized zeolite crystals. The saturation of the Fe-LTL films with CO2 and O2 at each concentration was reached within less than a minute. The Fe-LTL films detected both oxygen and carbon dioxide in contrast, to the pure LTL zeolite film.

关键词： zeolite films detection of CO2 and O2 adsorption

High-Temperature Thermodynamic Investigation of Nano-Dispersed Nitrides Obtained in Thermal plasma

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

plasma Science and Technology 2007年第2期9卷 174-176页

作者： M. georgieva G. VISSOKOV Iv. GRANCHAROV L. BRAKALOV Department of Technology of Inorganic Substances University of Chemical Technology andMetal|urgy 8 K. Okhridski Blvd. 1756 Sofia Bulgaria

The nitrides of transient metals have a high hardness, thermal stability, remarkable wear resistance in aggressive chemical mediums, melted metals and alloys, high corrosion resistance, and low coefficient of electric resistance. Under the conditions of low-temperature argon plasma （LTp）, thermodynamic investigations were conducted in the process of obtaining of A1N, TiN and Si3N4 in a temperature range of 1000 K to 6000 K. To investigate the thermodynamic possibility of obtaining nitrides, a computer model was used which provided the equilibrium composition of gaseous and solid phases at different temperatures. The conditions for chemical equilibrium of the system were based on the minimization of Gibbs＇ energy.

关键词： plasma-chemical treatment nitrides thermodynamic analysis

Controversies regarding transplantation of mesenchymal stem cells

在线全文

学校读者我要写书评

暂无评论

World Journal of Transplantation 2024年第2期14卷 48-61页

作者： Tsvetelina Velikova Tereza Dekova Dimitrina georgieva Miteva Department of Medical Faculty Sofia University St.Kliment OhridskiSofia 1407Bulgaria Department of Genetics Faculty of BiologySofia University St.Kliment OhridskiSofia 1164Bulgaria

Mesenchymal stem cells(MSCs)have tantalized regenerative medicine with their therapeutic potential,yet a cloud of controversies looms over their clinical *** comprehensive review navigates the intricate landscape of MSC controversies,drawing upon 15 years of clinical experience and *** delve into the fundamental properties of MSCs,exploring their unique immuno-modulatory capabilities and surface *** heart of our inquiry lies in the controversial applications of MSC transplantation,including the perennial debate between autologous and allogeneic sources,concerns about efficacy,and lingering safety ***,we unravel the enigmatic mechanisms surro-unding MSC transplantation,such as homing,integration,and the delicate balance between differentiation and paracrine *** also assess the current status of clinical trials and the ever-evolving regulatory *** we peer into the future,we examine emerging trends,envisioning personalized medicine and innovative delivery *** review provides a balanced and informed perspective on the controversies,offering readers a clear understanding of the complexities,challenges,and potential solutions in MSC transplantation.

关键词： Mesenchymal stem cells Transplantation controversies Regenerative medicine Autoimmune diseases Chronic inflammatory illnesses Tumor growth Metastasis Therapeutic potential Clinical use of mesenchymal stem cell

Sustainable energy management of solar greenhouses using open weather data on MACQU platform

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2018年第1期11卷 74-82页

作者： Li Li Jieyu Li Haihua Wang Ts.georgieva K.p.Ferentinos K.G.Arvanitis N.A.Sigrimis Key Laboratory on Modern precision Agriculture System Integration Research of Ministry of Education China Agricultural UniversityBeijing 100083China Key Laboratory of Agricultural Information Acquisition Technology of Ministry of Agriculture China Agricultural UniversityBeijing 100083China Department of Automatics and Mechatronics University of RuseRuse 7017Bulgaria Hellenic Agricultural Organization“Demeter” Institute of Soil&Water ResourcesDept.of Agricultural Engineering61 Dimokratias Av.13561AthensGreece&Research Advisor at Geomations SAspinoff of Agricultural University of Athens Department of Natural Resources Management&Agricultural Engineering Agricultural University of AthensAthens 11855Greece Director R&D Department Geosmart IKEspinout of Geomations of AUANafplio 21100Greece

precision energy management is very important for sustainability development of solar greenhouses,since huge energy demand for agricultural production both in quantity and quality.A proactive energy management,according to the optimal energy utilization in a look-ahead period with weather prediction,is presented and tested in this research.A multi-input-multi-output linear model of the energy balance of solar greenhouses based on on-line identification system can simulate greenhouse behavior and allow for predictive *** good time allocation of available solar energy can be achieved by intelligent use of controls,such as store/retrieve fans and ventilation windows,*** energy to warm up the air or to be stored in the storage elements(wall,soil,etc.)or to be exhausted to *** proactive energy management can select an optimal trajectory of air temperature for the forecasted weather period to minimize plants’thermal‘cost’defined by an‘expert’in terms of set-points for the specific *** selection of temperature trajectory is formulated as a generalized traveling salesman problem(GTSp)with precedence constraints and is solved by a genetic algorithm(GA)in this *** simulation study showed good potential for energy saving and timely allocation to prevent excessive crop *** active control elements in addition to predefining and applying,within energy constraints,optimal climate in the greenhouse,it also reduces the energy deficit,*** working hours of the‘heater’in the sustained freezing weather,as well as the ventilation hours,that is,more energy harvest in the warm *** intelligent solar greenhouse management system is being migrated to the web for serving a‘customer base’in the Internet plus *** capacity,of the concrete ground CAUA system(CAUA is an abbreviations from both China Agricultural University and Agricultural University of Athens),to implement web‘updates’of criteria,open weather data and models,on which control

关键词： solar greenhouse precision energy management energy-saving open weather data traveling salesman optimization

preliminary in vitro evaluation of neuroprotective and monoamine oxidase type B inhibitory effects of newly synthesized 8-aminocaffeines

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2019年第6期14卷 971-972页

作者： Magdalena Kondeva-Burdina Maya georgieva Alexandra Kasabova-Angelova Virginia Tzankova Alexander Zlatkov Laboratory of Drug Metabolism and Drug Toxicity Department of PharmacologyPharmacotherapy and ToxicologyFaculty of PharmacyMedical University of Sofia Department of pharmaceutical Chemistry Faculty of PharmacyMedical University of Sofia

The expected growth of the elderly population at highest risk for parkinson’s disease(pD)in the next decades makes the identification of factors that promote or prevent the disease an important *** addition,new therapies-aiming to delay the progression of pD are also needed(prediger,2010).However,there have been few clinical trials designed to investigate *** the application of an appropriate in vitro model such as the neuroblastoma SH-SY5Y cell line is extremely *** cells were selected due to its human origin,catecholaminergic neuronal properties,and ease of maintenance(Xicoy et al.,2017).

关键词： preliminary neuroprotective monoamine oxidase

Applications of time series analysis in epidemiology: Literature review and our experience during COVID-19 pandemic

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2023年第29期11卷 6974-6983页

作者： Latchezar Tomov Lyubomir Chervenkov Dimitrina georgieva Miteva Hristiana Batselova TsvetelinaVelikova Department of Informatics New Bulgarian UniversitySofia 1618Bulgaria Department of Diagnostic Imaging Medical University PlovdivPlovdiv 4000Bulgaria Department of Genetics Faculty of BiologySofia University"St.Kliment Ohridski"Sofia 1164Bulgaria Department of Epidemiology and Disaster Medicine Medical UniversityUniversity Hospital"St George"Plovdiv 4000Bulgaria Department of Medical Faculty Sofia UniversitySt.Kliment OhridskiSofia 1407Bulgaria

Time series analysis is a valuable tool in epidemiology that complements the classical epidemiological models in two different ways:prediction and *** is related to explaining past and current data based on various internal and external influences that may or may not have a causative *** is an exploration of the possible future values based on the predictive ability of the model and hypothesized future values of the external and/or internal *** time series analysis approach has the advantage of being easier to use(in the cases of more straightforward and linear models such as Auto-Regressive Integrated Moving Average).Still,it is limited in forecasting time,unlike the classical models such as *** applicability in forecasting comes from its better accuracy for short-term *** its basic form,it does not assume much theoretical knowledge of the mechanisms of spreading and mutating pathogens or the reaction of people and regulatory structures(governments,companies,etc.).Instead,it estimates from the data *** predictive ability allows testing hypotheses for different factors that positively or negatively contribute to the pandemic spread;be it school closures,emerging variants,*** can be used in mortality or hospital risk estimation from new cases,seroprevalence studies,assessing properties of emerging variants,and estimating excess mortality and its relationship with a pandemic.

关键词： Time series analysis Epidemiology COVID-19 pandemic Auto-regressive integrated moving average Excess mortality Seroprevalence

Surveilling Russell body Helicobacter pylori-negative gastritis: A case report and review of literature

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2020年第33期26卷 5050-5059页

作者： Milena peruhova Monika peshevska-Sekulovska Viktoriya georgieva Gabriela panayotova Dorian Dikov Department of Gastroenterology University Hospital LozenetzSofia 1407Bulgaria Department of General and Clinical pathology Grand Hôpital de l'Est FrancilienJossigny 77600France

BACKGROUND Russell body gastritis(RBG)is very rare type of chronic inflammation of gastric *** pathologic hallmark of the disease is Russell bodies(RB)which represent accumulation of eosinophilic cytoplasmic inclusions in endoplasmic reticulum of mature plasma cells(Mott cells).Most published cases are associated with Helicobacter pylori(***)infection because of correlation between plasma cell activation and antigenic *** are insufficient data about ***-negative RBG and very little is known about the natural course of the *** SUMMARY A 51-year-old male patient underwent endoscopic screening for mild iron deficiency *** revealed diffuse hyperemia,edema and nodularity of the fundic and corpus *** to non-specific endoscopic findings and iron-deficiency anemia our preliminary diagnosis was diffuse type of gastric carcinoma or gastric *** specimens of gastric mucosa showed inflammatory infiltrate rich in Mott cells,consisting entirely of cytoplasmic *** of nuclear atypia and mitosis of the plasma cells,polyclonal pattern of the Mott cells and negative staining for cytokeratins favored diagnosis of *** patient was treated with proton-pump inhibitor for 8 ***-term clinical and endoscopic surveillance was ***,there was no improvement in endoscopic features of the gastric mucosa in three consecutive gastroscopies,histopathological findings demonstrated that the chronic inflammatory infiltrate in the fundic mucosa is less pronounced,rich in plasma cells,with almost absent RB and Mott *** The prognosis of this entity is uncertain,that is why these patients are subjects of continuous follow up.

关键词： Russell body gastritis Helicobacter pylori-negative Treatment Mature plasma cells Case report

MNN-XSS:Modular Neural Network Based Approach for XSS Attack Detection

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第2期70卷 4075-4085页

作者： Ahmed Abdullah Alqarni Nizar Alsharif Nayeem Ahmad Khan Lilia georgieva Eric pardade Mohammed Y.Alzahrani Department of Computer Sciences and Information Technology AlBaha UniversityAlBahaSaudi Arabia Department of Computer Science Heriot-Watt UniversityEdinburghUK Department of Computer Science and Information Technology La Trobe UniversityMelbourneVIC 3086Australia

The rapid growth and uptake of network-based communication technologies have made cybersecurity a significant challenge as the number of cyber-attacks is also increasing.A number of detection systems are used in an attempt to detect known attacks using signatures in network *** recent years,researchers have used different machine learning methods to detect network attacks without relying on those *** methods generally have a high false-positive rate which is not adequate for an industry-ready intrusion detection *** this study,we propose and implement a new method that relies on a modular deep neural network for reducing the false positive rate in the XSS attack detection *** were performed using a dataset consists of 1000 malicious and 10000 benign *** model uses 50 features selected by using pearson correlation method and will be used in the detection and preventions of XSS *** results obtained from the experiments depict improvement in the detection accuracy as high as 99.96%compared to other approaches.

关键词： Cybersecurity XSS deep learning modular neural network