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Multifunctional HDPE/Cu biocidal nanocomposites for MEX additive manufactured parts: Perspectives for the defense industry

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Defence Technology（防务技术） 2024年第8期38卷 16-32页

作者： Nectarios Vidakis Nikolaos Michailidis markos petousis Nektarios K.Nasikas Vassilios Saltas Vassilis Papadakis Nikolaos Mountakis Apostolos Argyros Mariza Spiridaki Ioannis Valsamos Department of Mechanical Engineering Hellenic Mediterranean UniversityHeraklion 71410Greece Physical Metallurgy Laboratory Mechanical Engineering DepartmentSchool of EngineeringAristotle University of ThessalonikiThessaloniki 54124Greece Centre for Research&Development of Advanced Materials(CERDAM) Center for Interdisciplinary Research and InnovationBalkan CentreThessaloniki 57001Greece Division of Mathematics and Engineering Sciences Department of Military SciencesHellenic Army AcademyVari GR16673AtticaGreece Department of Electronic Engineering Hellenic Mediterranean UniversityChania 73133Greece Department of Industrial Design and Production Engineering University of West AtticaAthens 12244Greece Institute of Electronic Structure and Laser Foundation for Research and Technology-HellasHeraklion 70013Greece

In this study, we investigated the performance improvement caused by the addition of copper(Cu)nanoparticles to high-density polyethylene(HDPE) matrix material. Composite materials, with filler percentages of 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0 wt% were synthesized through the material extrusion(MEX)3D printing technique. The synthesized nanocomposite filaments were utilized for the manufacturing of specimens suitable for the experimental procedure that followed. Hence, we were able to systematically investigate their tensile, flexural, impact, and microhardness properties through various mechanical tests that were conducted according to the corresponding standards. Broadband Dielectric Spectroscopy was used to investigate the electrical/dielectric properties of the composites. Moreover, by employing means of Raman spectroscopy and thermogravimetric analysis(TGA) we were also able to further investigate their vibrational, structural, and thermal properties. Concomitantly, means of scanning electron microscopy(SEM), as well as atomic force microscopy(AFM), were used for the examination of the morphological and structural characteristics of the synthesized specimens, while energy-dispersive Xray spectroscopy(EDS) was also performed in order to receive a more detailed picture on the structural characteristics of the various synthesized composites. The corresponding nanomaterials were also assessed for their antibacterial properties regarding Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) with the assistance of a method named screening agar well diffusion. The results showed that the mechanical properties of HDPE benefited from the utilization of Cu as a filler, as they showed a notable improvement. The specimen of HDPE/Cu 4.0 wt% was the one that presented the highest levels of reinforcement in four out of the seven tested mechanical properties(for example, it exhibited a 36.7%improvement in the flexural strength, compared to the pure matrix). At the same

关键词： High-density polyethylene(HDPE) Copper(Cu) Material extrusion(MEX) Mechanical performance Electrical properties Antibacterial Defense and security

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Biochar filler in MEX and VPP additive manufacturing:characterization and reinforcement effects in polylactic acid and standard grade resin matrices

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Biochar 2023年第1期5卷 674-694页

作者： Nectarios Vidakis Dimitrios Kalderis markos petousis Emmanuel Maravelakis Nikolaos Mountakis Nikolaos Bolanakis Vassilis Papadakis Department of Mechanical Engineering Hellenic Mediterranean University71410 HeraklionGreece Department of Electronic Engineering Hellenic Mediterranean University73133 ChaniaGreece Institute of Electronic Structure and Laser of the Foundation for Research and Technology-Hellas 71110 HeraklionGreece

The development of sustainable and functional biocomposites remains a robust research and industrial ***,the efficiency of using eco-friendly biochar as reinforcement in Additive Manufacturing(AM)was *** AM technologies were applied,i.e.,vat photopolymerization(VPP)and material extrusion(MEX).A standard-grade resin in VPP and the also eco-friendly biodegradable Polylactic Acid(PLA)in the MEX process were selected as polymeric *** was prepared in the study from olive *** were developed for both 3D printing processes at different biochar *** were 3D-printed and mechanically tested after international test *** Analysis and Raman revealed the thermal and structural characteristics of the *** and fractographic features were derived,among others,with Scanning Electron Microscopy(SEM)and Atomic Force Microscopy(AFM).Biochar was proven to be sufficient reinforcement agent,especially in the filament MEX process,reaching more than 20%improvement at 4 wt.%loading in tensile strength compared to the pure PLA control *** the VPP process,results were not as satisfactory,still,a 5%improvement was achieved in the flexural strength with 0.5 wt.%biochar *** findings prove the strong potential of biochar-based composites in AM applications,too.

关键词： Biochar Resin Polylactic acid(PLA) Vat photopolymerization(VPP) Material extrusion(MEX) Mechanical characterization

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Assessment of Seasonal Rainfall Prediction in Ethiopia: Evaluating a Dynamic Recurrent Neural Network to Downscale ECMWF-SEAS5 Rainfall

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Advances in Atmospheric Sciences 2024年第11期41卷 2230-2244页

作者： Abebe KEBEDE Kirsten WARRACH-SAGI Thomas SCHWITALLA Volker WULFMEYER Tesfaye ABEBE markos WARE Hawassa University College of Agriculture P.O.Box 05HawassaEthiopia Institute of Physics and Meteorology University of HohenheimP.O.Box 70599StuttgartGermany Arba Minch University Water Institute of Technology Faculty of Meteorology and HydrologyP.O.Box 21Arba MinchEthiopia

Seasonal rainfall plays a vital role in both environmental dynamics and decision-making for rainfed agriculture in Ethiopia, a country often impacted by extreme climate events such as drought and flooding. Predicting the onset of the rainy season and providing localized rainfall forecasts for Ethiopia is challenging due to the changing spatiotemporal patterns and the country's rugged topography. The Climate Hazards Group Infra Red Precipitation with Station Data(CHIRPS), ERA5-Land total precipitation and temperature data are used from 1981–2022 to predict spatial rainfall by applying an artificial neural network(ANN). The recurrent neural network(RNN) is a nonlinear autoregressive network with exogenous input(NARX), which includes feed-forward connections and multiple network layers, employing the Levenberg Marquart algorithm. This method is applied to downscale data from the European Centre for Medium-range Weather Forecasts fifth-generation seasonal forecast system(ECMWF-SEAS5) and the Euro-Mediterranean Centre for Climate Change(CMCC) to the specific locations of rainfall stations in Ethiopia for the period 1980–2020. Across the stations, the results of NARX exhibit strong associations and reduced errors. The statistical results indicate that, except for the southwestern Ethiopian highlands, the downscaled monthly precipitation data exhibits high skill scores compared to the station records, demonstrating the effectiveness of the NARX approach for predicting local seasonal rainfall in Ethiopia's complex terrain. In addition to this spatial ANN of the summer season precipitation, temperature, as well as the combination of these two variables, show promising results.

关键词： station prediction downscaling artificial neural networks rainfall

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COVID-19 in pregnancy:Perinatal outcomes and complications

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World Journal of Virology 2024年第4期13卷 62-73页

作者： Karolina Akinosoglou Georgios Schinas Evangelia Papageorgiou Theodoros Karampitsakos VasilikiDimakopoulou Eleni Polyzou Argyrios Tzouvelekis markos Marangos Despoina Papageorgiou Nikolaos Spernovasilis George Adonakis Department of Medicine University of PatrasPatras 26504Greece Department of Obstetrics and Gynecology University General Hospital of PatrasPatras 26504Greece Department of Pneumonology University General Hospital of PatrasPatras 26504Greece Department of Infectious Diseases German Oncology CenterLimassol 4108LimassolCyprus

BACKGROUND The risk of severe coronavirus disease 2019(COVID-19)in pregnant women is *** To examine the outcomes of pregnant women with COVID-19 and report perinatal outcomes and complications,while providing a brief review of current *** The study included pregnant women presenting from April 2020 to February 2022 to the emergency department(ED)of a tertiary *** retrospectively recorded the maternal and perinatal files,including patient epidemiological and clinical characteristics,laboratory values,outcomes,treatment modalities and associations were *** Among the 60 pregnant women,25%required hospitalization,all of whom were *** delivery occurred in 30%of *** percent of neonates required admission to the neonatal intensive care unit,and 5%were classified as small for their gestational *** mothers survived COVID-19 and pregnancy,with 6.6%requiring invasive mechanical *** delivery rates did not differ between hospitalized and non-hospitalized pregnant women;composite unfavorable perinatal outcomes,including stillbirth,small for gestational age,or neonatal intensive care unit(ICU)admission,did not significantly increase in the cases hospitalized for COVID-19(P=0.09).The odds of hospitalization increased 2.3-fold for each day of delayed ED presentation[***(95%CI:1.46-3.624),P<0.001].Comorbidity status was an independent predictor of hospitalization,albeit with marginal significance[***=16.13(95%CI:1.021-255.146),P=0.048].No independent predictors of adverse fetal outcome(composite)were identified,and eventual hospitalization failed to reach statistical significance by a slight margin(P=0.054).CONCLUSION Delayed ED presentation and comorbidities increase hospitalization *** study highlights the importance of continuous and specific guidance for managing pregnant COVID-19 patients,including timely and appropriate interventions to minimize maternal and perinatal morbidity an

关键词： SARS-CoV-2 COVID-19 Pregnancy Maternal outcomes Preterm delivery

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Beyond the SDG 15.3.1 Good Practice Guidance 1.0 using the Google Earth Engine platform: developing a self-adjusting algorithm to detect significant changes in water use efficiency and net primary production

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Big Earth Data 2023年第1期7卷 59-80页

作者： Andrea markos Neil Sims Gregory Giuliani Foundation for the Conservation of the Chiquitano Forest Santa CruzBolivia Bolivian National Academy of Sciences La PazBolivia Centre for Earth Observation Space&AstronomyCSIROClaytonAustralia GEO LDN Initiative Institute for Environmental Sciences EnviroSPACE LabUniversity of GenevaGenevaSwitzerland Institute for Environmental Sciences GRID-GenevaUniversity of GenevaGenevaSwitzerland

Monitoring changes in Annual Net Primary Productivity(ANPP)is required for reporting on UN Sustainable Development Goal(SDG)Indicator 15.3.1:the proportion of land that is degraded over the total land *** time-series observations of ANPP to derive Water Use Efficiency(WUE;a measure of ANPP per unit of evapotranspiration)can minimize the influence of climate factors on ANPP observations and highlight the influence of non-climatic drivers of degradation such as land use *** the ANPP and WUE time series may be useful for identifying the primary drivers of land degradation,which could be used to support the Land Degradation Neutrality objectives of the UN Convention to Combat Desertification(UNCCD).This paper presents an algorithm for the Google Earth Engine(freely and openly available upon request-http://***/10.5281/zenodo.4429773)to calculate and compare ANPP and WUE time series for Santa Cruz,Bolivia,which has recently experienced an intensification in its land *** code builds on the Good Practice Guidance document(ver-sion 1)for monitoring SDG Indicator *** use the MODIS 16-day average,250 m resolution to demonstrate that the Enhanced Vegetation Index(EVI)responds faster to changes in water avail-ability than the Normalized Difference Vegetation Index(NDVI).We also consider the relationships between ANPP and *** and concordant trends may highlight good agricultural practices or increased resilience in ecosystem structure and productivity when they are positive or reducing resilience and functional integrity if *** sign and significance of the correlation between ANPP and WUE may also diverge over *** further analysis,it may be possible to interpret this relationship in terms of the drivers of change in plant productivity and ecosystem resilience.

关键词： Land degradation land productivity water use efficiency Google Earth Engine MODIS Good Practice Guidance SDG 15.3.1

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Coarse-Grained Langevin Approximations and Spatiotemporal Acceleration for Kinetic Monte Carlo Simulations of Diffusion of Interacting Particles

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Chinese Annals of Mathematics,Series B 2009年第6期30卷 653-682页

作者： Sasanka ARE markos A. KATSOULAKIS Anders SZEPESSY Department of Mathematics and Statistics University of MassachusettsAmherstMA 01003-9305USA Department of Applied Mathematics University of Crete and Foundation of Research and TechnologyHellasHeraklion 71405Greece Matematiska Institutionen Kungliga Tekniska Hgskolan (Royal Institute of Technology)SE-100 44 StockholmSweden

Kinetic Monte Carlo methods provide a powerful computational tool for the simulation of microscopic processes such as the diffusion of interacting particles on a surface, at a detailed atomistic level. However such algorithms are typically computationatly expensive and are restricted to fairly small spatiotemporal scales. One approach towards overcoming this problem was the development of coarse-grained Monte Carlo algorithms. In recent literature, these methods were shown to be capable of efficiently describing much larger length scales while still incorporating information on microscopic interactions and fluctuations. In this paper, a coarse-grained Langevin system of stochastic differential equations as approximations of diffusion of interacting particles is derived, based on these earlier coarse-grained models. The authors demonstrate the asymptotic equivalence of transient and long time behavior of the Langevin approximation and the underlying microscopic process, using asymptotics methods such as large deviations for interacting particles systems, and furthermore, present corresponding numerical simulations, comparing statistical quantities like mean paths, auto correlations and power spectra of the microscopic and the approximating Langevin processes. Finally, it is shown that the Langevin approximations presented here are much more computationally efficient than conventional Kinetic Monte Carlo methods, since in addition to the reduction in the number of spatial degrees of freedom in coarse-grained Monte Carlo methods, the Langevin system of stochastic differential equations allows for multiple particle moves in a single timestep.

关键词： Kinetic Monte Carlo methods Diffusion Fluctuations

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Evaluating learning and change in orthopaedics: What is the evidence-base?

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World Journal of Orthopedics 2019年第11期10卷 378-386页

作者： Epaminondas markos Valsamis Mohamed Sukeik Nuffield Orthopaedic Centre Oxford University Hospitals NHS TrustOxfordOX37LDUnited Kingdom Department of Trauma and Orthopaedics Dr.Sulaiman Al-Habib Hospital-Al KhobarKing Salman Bin Abdulaziz RdAl BandariyahAl Khobar 34423Saudi Arabia

Learning and change are key elements of clinical governance and are responsible for the progression of our *** orthopaedics has been slow to embrace quality improvement,recent years have seen global developments in surgical education,quality improvement,and patient outcome *** review covers recent advances in the evaluation of learning and change and identifies the most important research questions that remain *** into proxies of learning is improving but more work is required to identify the best proxy for a given *** curves are becoming commonplace but are poorly integrated into postgraduate training curricula and there is little agreement over the most appropriate method to analyse learning curve *** various organisations promoting centralisation of care,learning curve analysis is more important than ever *** use of simulation in orthopaedics is developing but is yet to be formally mapped to resident training *** outcome research is rapidly changing,with an increased focus on quality of life *** are key to patients and their *** analysis is increasingly seen in orthopaedic manuscripts and this needs to continue to improve evidence-based ***-scale international,multi-centre randomised trials are gaining popularity and updated guidance on sample size estimation needs to become widespread.A global lack of surgeon equipoise will need to be *** improvement projects frequently employ interrupted time-series analysis to evaluate *** technique’s limitations must be acknowledged,and more work is required to improve the evaluation of change in a dynamic healthcare environment where multiple interventions frequently *** in the evaluation of learning and change are needed to drive improved international surgical education and increase the reliability,validity,and importance of the conclusions drawn from orthopaedic research.

关键词： Learning Change Quality improvement Orthopaedics Surgical education

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Soft monolithic infrared neural interface for simultaneous neurostimulation and electrophysiology

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Light(Science & Applications) 2023年第6期12卷 1103-1116页

作者： Marcello Meneghetti Jaspreet Kaur Kunyang Sui Jakob F.Sørensen Rune W.Berg Christos markos DTU Electro Department of Electrical and Photonics EngineeringTechnical University of DenmarkDK-2800 KgsLyngbyDenmark Department of Neuroscience University of CopenhagenBlegdamsvej 3BDK-2200 Kbh NCopenhagenDenmark NORBLIS ApS Virumgade 35DDK-2830 VirumDenmark

Controlling neuronal activity using implantable neural interfaces constitutes an important tool to understand and develop novel strategies against brain *** neurostimulation is a promising alternative to optogenetics for controlling the neuronal circuitry with high spatial ***,bi-directional interfaces capable of simultaneously delivering infrared light and recording electrical signals from the brain with minimal inflammation have not yet been ***,we have developed a soft fibre-based device using high-performance polymers which are>100-fold softer than conventional silica glass used in standard optical *** developed implant is capable of stimulating the brain activity in localized cortical domains by delivering laser pulses in the 2μm spectral region while recording electrophysiological *** and local field potentials were recorded in vivo from the motor cortex and hippocampus in acute and chronic settings,*** analysis of the brain tissue indicated insignificant inflammatory response to the infrared pulses while the signal-to-noise ratio of recordings still remained *** neural interface constitutes a step forward in expanding infrared neurostimulation as a versatile approach for fundamental research and clinically translatable therapies.

关键词： neural stimulation recording

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Likelihood-based estimation and prediction for a measles outbreak in Samoa

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Infectious Disease Modelling 2023年第1期8卷 212-227页

作者： David Wu Helen petousis-Harris Janine Paynter Vinod Suresh Oliver J.Maclaren Department of Engineering Science University of AucklandGraftonAuckland1010New Zealand Department of General Practice and Primary Health Care University of AucklandGraftonAuckland1023New Zealand Auckland Bioengineering Institute University of AucklandGraftonAuckland1010New Zealand

Prediction of the progression of an infectious disease outbreak is important for planning and coordinating a *** equations are often used to model an epidemic outbreak's behaviour but are challenging to ***,these models can suffer from misspecification,which biases predictions and parameter *** models can help with misspecification but are even more expensive to simulate and perform inference ***,we develop an explicitly likelihood-based variation of the generalised profiling method as a tool for prediction and inference under model *** approach allows us to carry out identifiability analysis and uncertainty quantification using profile likelihood-based methods without the need for *** provide justification for this approach by introducing a new interpretation of the model approximation component as a stochastic *** preserves the rationale for using profiling rather than integration to remove nuisance parameters while also providing a link back to stochastic *** applied an initial version of this method during an outbreak of measles in Samoa in 2019e2020 and found that it achieved relatively fast,accurate *** we present the most recent version of our method and its application to this measles outbreak,along with additional validation.

关键词： Generalised profiling Likelihood-based inference Profile likelihood Parameter estimation Bootstrap Measles

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Validated LC-MS/MS method for simultaneous determination of SIM and its acid form in human plasma and cell lysate: Pharmacokinetic application

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Journal of Pharmaceutical Analysis 2012年第6期2卷 403-411页

作者： Tamer A. Ahmed Jamie Horn John Hayslip markos Leggas Department of Pharmaceutical Sciences College of Pharmacy University of Kentucky Markey Cancer Center University of Kentucky

Simvastatin （SIM） is a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor widely used in hyperlipidemia therapy. SIM has recently been studied for its anticancer activity at doses higher than those used for the hyperlipidemia therapy. This prompted us to study the pharmacokinetics of high-dose SIM in cancer patients. For this purpose, an LC-MS/MS method was developed to measure SIM and its acid form （SIMA） in plasma and peripheral blood mononuclear cells （PBMCs） obtained from patients. Chromatographic analyte separation was carried out on a reverse-phase column using 75：25 （% v/v） acetonitrile：ammonium acetate （0.1 M, pH 5.0） mobile phase. Detection was performed on a triple quadrupole mass spectrometer, equipped with a turbo ion spray source and operated in positive ionization mode. The assay was linear over a range 2.5-500 ng/mL for SIM and 5-500 ng/mL for SIMA in plasma and 2.5-250 ng/mL for SIM and 5-250 ng/mL for SIMA in cell lysate. Recovery was 〉 58% for SIM and 〉 75% for SIMA in both plasma and cell lysate. SIM and SIMA were stable in plasma, cell lysate and the reconstitution solution. This method was successfully applied for the determination of SIM and SIMA in plasma and PBMCs samples collected in the pharmacokinetic study of high-dose SIM in cancer patients.

关键词： Simvastatin LC-MS/MS Human plasma Cell lysate Pharmacokinetic High-dose

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