1,207 research outputs found
Static secondary ion mass spectrometry (S-SIMS) analysis of atmospheric plasma treated polypropylene films
How Advanced Change Patterns Impact the Process of Process Modeling
Process model quality has been an area of considerable research efforts. In
this context, correctness-by-construction as enabled by change patterns
provides promising perspectives. While the process of process modeling (PPM)
based on change primitives has been thoroughly investigated, only little is
known about the PPM based on change patterns. In particular, it is unclear what
set of change patterns should be provided and how the available change pattern
set impacts the PPM. To obtain a better understanding of the latter as well as
the (subjective) perceptions of process modelers, the arising challenges, and
the pros and cons of different change pattern sets we conduct a controlled
experiment. Our results indicate that process modelers face similar challenges
irrespective of the used change pattern set (core pattern set versus extended
pattern set, which adds two advanced change patterns to the core patterns set).
An extended change pattern set, however, is perceived as more difficult to use,
yielding a higher mental effort. Moreover, our results indicate that more
advanced patterns were only used to a limited extent and frequently applied
incorrectly, thus, lowering the potential benefits of an extended pattern set
A 13000 year environmental history of Lake Colbricon Inferiore (Trentino, Italia)
Lake sediments have long been used as an archive for paleoclimatic-paleoenvironmental reconstructions, with more and more refined techniques developed in the late 40 years. This work is an attempt to reconstruct with a multiproxy paleolimnological technique the ecosystem response in Colbricon Inferiore, a small high-mountain lakes located in the Paneveggio-Pale di S. Martino Natural Park(Trento, Italy). A ca. 360cm long core was retrieved with a piston core; a gravity corer was used for the most recent sediment. Chronology was established by a combination of 210Pb and 14C isotopes. Diatom assemblages show changes in species composition that could be associated to an initial warm phase (Allerod), a following colder one (YD) and a progressive amelioration of climate until the optimum (8500-3500). During the transition period (10000-8000) carotenoids point out to an increase of cyanobacteria (Echinenone and myxoxanthophyll) associated with an increase of fire frequency and the first settlement around Lake Colbricon. Along the climatic optimum, algal pigment are rather stable and Chryptophytes (alloxanthin) are well represented pointing to a high and stable water level. Diatom assemblages are dominated by the planktonic Discostella stelligeroides. At ca. 3500 yrs. B.P., a new phase begins with a decrease of D. stelligeroides and an increase of the small benthic fragilariaceae (Staurosira and Pseudostaurosira species) typical of cold-water conditions. At this level, there is a general increase of carotenoids and a shift in the ratio CD:TC. This suggest, rather than an increase in productivity, a change in the preservation conditions associated with the worsening of climate. After 2000 cal yr BP the lake seems quite stable: diatom assemblages are dominated by Staurosira and Pasudostaurosira species. Algal pigment are also quite stable apart myxoxanthophyll that increase in the more recent phase
Atmospheric pressure plasma and depositions of antibacterial coatings
Healthcare-associated infections (HCAI) are complications of healthcare that result in elevated patient morbidity and mortality. HCAI present a huge financial burden for patients, hospitals and insurers due to extended hospitalisation and associated care. According to the estimations, in the US alone, HCAI affects approximately 2 million patients annually, of whom approximately 90.000 patients die, with an estimated annual cost estimated to range from 28 billion to 45 billion US$. [1] European Union is facing the similar situation, the European Centre for Disease Prevention and control (ECDC) advice that approximately 4.1 million acute care patients acquire a HCAI annually, with 37.000 deaths directly attributed to HCAI. With increasing prevalence of HCAI across European countries and threatening development of antimicrobial resistance to widely used antibiotics, there is a recognised need for novel approach in battle against this healthcare burden [2]. One of the approaches involves a development and fabrication of materials with antimicrobial properties. Usually, these are coatings with integrated antibacterial agent that is responsible for the elimination of microorganisms that come into contact with active surface. There is a variety of different antibacterial compounds integrated in such coatings, such as different antibiotics, chemical compounds, peptides. Recently, metal nanoparticles (NPs) have been increasingly used in designing coatings with antibacterial properties due to their large surface-to-volume ration, physiochemical properties and biological multi-target mechanism of actions. Besides all beneficial properties of NPs their emergence of cytotoxicity is limiting their practical applications in human body. [3-4] To overcome this drawback it is important to design a new class of antibacterial coatings with firmly embedded NPs that allows controlled release of antimicrobial agent into the microenvironment. Atmospheric pressure plasma technology has shown a big promise as an alternative and cost-efficient method for deposition of coatings with antibacterial properties.
This contribution explores the potential of plasma-assisted approach for fabrication of antibacterial coatings, containing different metal NPs on medical textiles. Plasma-assisted deposition of coatings was carried out with so-called Ësandwich techniqueË, where nanoparticles were embedded between two layers in order to tailor the desirable ion release and to prolong antibacterial effect of fabrics. Antibacterial effects of different nano-coatings were tested against G+ and G- bacterial species, Staphylococcus aureus and Escherichia coli, respectively. Besides antibacterial properties, potential cytotoxic effects were also studied. The study demonstrates that atmospheric pressure plasma can be an efficient technique for deposition of antibacterial coatings containing metal NPs. Medical textiles with plasma-assisted nano-coatings showed effective antibacterial properties. The choice of proper metal antimicrobial agent and optimal concentration of NPs should be considered in regards to potential cytotoxic effects when these materials would be used in medical environments.info:eu-repo/semantics/publishedVersio
Atmospheric-pressure plasma spray deposition of silver/HMDSO nanocomposite on polyamide 6,6 with controllable antibacterial activity
"Paper presented at the ICON2019 conferences in Ăorlu, TekirdaÄ, Turkey April 17-19, 2019"Novel coatings containing silver nanoparticles (AgNPs) with strong bonding and controllable antibacterial activity on polyamide 6,6 fabric were produced by dielectric barrier discharge (DBD) plasmaassisted deposition at atmospheric pressure and hexamethyldisiloxane (HMDSO) layers. Silver ion release was tuned using a âsandwichâ coating structure to prolong
the antibacterial effect. The novel spray-assisted deposition increased deposition rates of AgNPs using atmospheric pressure DBD plasma treatment when an HMDSO layer was applied. An increase in AgNPs deposition in plasma treated samples and antimicrobial activity against Gram-negative (Escherichia coli) for samples with an additional HMDSO layer was observed. These coatings allow the development of new and safe wound dressings able to switch the antimicrobial effect against Gram- positive and Gram-negative bacteria by washing the dressing at high temperature (75 oC) before application.This work was funded by European Regional Development
funds (FEDER) through the Competitiveness and Internationalization Operational Program (POCI) â COMPETE
and by National Funds through Portuguese Fundação
para a CiĂȘncia e Tecnologia (FCT) under the project UID/
CTM/00264/2019. Ana Ribeiro acknowledges FCT for its
doctoral grant SFRH/BD/137668/2018. Andrea Zille also
acknowledges fnancial support of the FCT through an
Investigator FCT Research contract (IF/00071/2015) and the
project PTDC/CTM-TEX/28295/2017 fnanced by FCT, FEDER, and POCI in the frame of the Portugal 2020 program
Antibacterial nanocomposites based on Ag NPs and HMDSO deposited by atmospheric pressure plasma
The development of new multifunctional coatings with antimicrobial properties has a special interest in several applications for pharmaceutical and medical products. This work reports on the deposition of antimicrobial coatings based on silver nanoparticles (Ag NPs) embedded in an organosilicon film onto woven and nonwoven textiles. The Ag nanoparticles admixed with hexamethyldisiloxane (HMDSO) vapours are introduced by means of an atomizer system in the remote discharge of an atmospheric pressure plasma source operating in argon. The chemical properties and the surface morphology of the coatings with antimicrobial potential are discussed.This work was performed within the M-ERA-NET
project PlasmaTex, contract 31/2016/ UEFISCDI. The
financial support from the Ministry of Research and
Innovation under the Nucleus contract 4N/2016 is
gratefully acknowledged.info:eu-repo/semantics/publishedVersio
A phase II study of raltitrexed and gemcitabine in patients with advanced pancreatic carcinoma
Advanced adenocarcinoma of the pancreas has a very poor prognosis. The aim of this study was to assess the efficacy and tolerability of a combination of the chemotherapeutic agents gemcitabine and raltitrexed. ChemonaĂŻve patients with advanced adenocarcinoma of the pancreas were treated with a combination of raltitrexed (3.5âmgâmâ2 on day 1 of a 21-day treatment cycle) and gemcitabine (800âmgâmâ2 intravenously (i.v.) on days 1 and 8 of a 21-day cycle). Between April 2000 and February 2003, 27 patients were enrolled onto the study. The mean duration of treatment was 11 weeks. Four of 27 patients experienced at least one episode of grade 3 or 4 neutropenia. One patient with grade 4 neutropenia died due to sepsis. Four of 27 patients experienced grade 4 diarrhoea. There was one partial remission (4%) and 12 patients experienced disease stabilisation (44%). The 6-month and 1-year survival rates were 37 and 11%, respectively. Symptomatic benefit occurred in seven (26%) patients. We conclude that a combination of raltitrexed and gemcitabine, using the schedule and doses in this study, cannot be recommended for patients with advanced pancreatic cancer
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