To find out the relationship between the oil-based mud,the formation fluid and the extracted gas,we use a thermodynamic approach based on static headspace gas chromatography technique to calculate the partition coeffi...To find out the relationship between the oil-based mud,the formation fluid and the extracted gas,we use a thermodynamic approach based on static headspace gas chromatography technique to calculate the partition coefficients of 47 kinds of light hydrocarbons compounds between nC5 and nC8 in two kinds of oil-based mud-air systems,and reconstruct the original formation fluid composition under thermodynamic equilibrium.The oil-based drilling mud has little effect on the formation fluid compositions in the range of nC5-nC8(less than 1%for low-toxicity oil-based mud and less than 10%for oil-based mud).For most light hydrocarbon compositions,the partition coefficients obtained by vapor phase calibration and the direct quantitative methods have errors of less than 10%,and the partition coefficients obtained by direct quantitative method are more accurate.The reconstructed compositions of the two kinds of crude oil have match degrees of 91%and 89%with their real compositions,proving the feasibility and accuracy of reconstructing the composition of original formation fluid by using partition coefficients of light hydrocarbon compositions between nC5 and nC8.展开更多
Among the several types of inorganic nanoparticles available,silica nanoparticles(SNP)have earned their relevance in biological applications namely,as bioimaging agents.In fact,uorescent SNP(FSNP)have been explored in...Among the several types of inorganic nanoparticles available,silica nanoparticles(SNP)have earned their relevance in biological applications namely,as bioimaging agents.In fact,uorescent SNP(FSNP)have been explored in this-eld as protective nanocarriers,overcoming some limitations presented by conventional organic dyes such as high photobleaching rates.A crucial aspect on the use of uorescent SNP relates to their surface properties,since it determines the extent of interaction between nanoparticles and biological systems,namely in terms of colloidal stability in water,cellular recognition and internalization,tracking,biodistribution and speci-city,among others.Therefore,it is imperative to understand the mechanisms underlying the interaction between biosystems and the SNP surfaces,making surface functionalization a relevant step in order to take full advantage of particle properties.The versatility of the surface chemistry on silica platforms,together with the intrinsic hydrophilicity and biocompatibility,make these systems suitable for bioimaging applications,such as those mentioned in this review.展开更多
Zwitterionic polymers are known to interact with cells and have been shown to reveal cancer cell specificity.In this work,the importance of the chemistry of the polymer backbone for the cellular specificity of amino-a...Zwitterionic polymers are known to interact with cells and have been shown to reveal cancer cell specificity.In this work,the importance of the chemistry of the polymer backbone for the cellular specificity of amino-acid-derived polyzwitterions is demonstrated.A series of glutamic acid(Glu)-based vinyl monomers(i.e.,an acrylate,a methacrylate,an acrylamide,and a methacrylamide)were prepared and used for reversible addition-fragmentation chain-transfer(RAFT)polymerisation,yielding defined polymers with narrow size distribution(Ð<1.3).All Glu-functionalised,zwitterionic polymers revealed high cytocompatibility;however,differences in cellular association and specificity were observed.In particular,the methacrylamide-derived polymers showed high association with both,breast cancer cells and non-cancerous dendritic cells and,consequently,lack specificity.In contrast,high specificity to only breast cancer cells was observed for polyacrylates,-methacrylates,and-acrylamides.Detailed analysis of the polymers revealed differences in hydrophobicity,zeta potential,and potential side chain hydrolysis,which are impacted by the polymer backbone and might be responsible for the altered the cell association of these polymers.It is shown that a slightly negative net charge is preferred over a neutral charge to retain cell specificity.This was also confirmed by association experiments in the presence of competitive amino acid transporter substrates.The affinity of slightly negatively charged Glu-derived polymers to the xCT Glu/cystine cell membrane antiporter was found to be higher than that of neutrally charged polymers.Our results emphasise the importance of the polymer backbone for the design of cell-specific polymers.This study further highlights the potential to tailor amino-acid-derived zwitterionic materials beyond their side chain functionality.展开更多
Background:Nowadays,a wide range of wound dressings is already commercially available.The selection of the dressing is of paramount importance as inappropriate wound management and dressing selection can delay the wou...Background:Nowadays,a wide range of wound dressings is already commercially available.The selection of the dressing is of paramount importance as inappropriate wound management and dressing selection can delay the wound healing process.Not only can this be distressing for the patient,but it can also contribute to complications such as maceration and subsequent infection.Many researchers are targeting the design of dressings with superior properties over existing commercial dressings.However,reported results in the state-of-the-art are rarely benchmarked against commercial dressings.The aim of this study was to determine several characteristics of a large variety of the most frequently used commercial wound dressings,providing an overview for both practitioners and researchers.Methods:For this comparative study,11 frequently used commercial wound dressings were selected,representing the different types.The morphology was studied using scanning electron microscopy.The dressings were characterized in terms of swelling capacity(water,phosphate buffered saline and simulated wound fluid),moisture vapour transmission rate(MVTR)and moisture uptake capacity(via dynamic vapour sorption)as well as mechanical properties using tensile testing and texturometry.Results:The selected dressings showed distinctive morphological differences(fibrous,porous and/or gel)which was reflected in the different properties.Indeed,the swelling capacities ranged between 1.5 and 23.2 g/g(water),2.1 and 17.6 g/g(phosphate buffered saline)or 2.9 and 20.8 g/g(simulated wound fluid).The swelling capacity of the dressings in water increased even further upon freeze-drying,due to the formation of pores.The MVTR values varied between 40 and 930 g/m^(2)/24 h.The maximal moisture uptake capacity varied between 5.8%and 105.7%at 95%relative humidity.Some commercial dressings exhibited a superior mechanical strength,due to either being hydrophobic or multi-layered.Conclusions:The present work not only offers insight into a valuable toolbox of suitable wound dressing characterization techniques,but also provides an extensive landscaping of commercial dressings along with their physico-chemical properties,obtained through reproducible experimen-tal protocols.Furthermore,it ensures appropriate benchmark values for commercial dressings in all forthcoming studies and could aid researchers with the development of novel modern wound dressings.The tested dressings either exhibited a high strength or a high swelling capacity,suggesting that there is still a strong potential in the wound dressings market for dressings that possess both.展开更多
文摘To find out the relationship between the oil-based mud,the formation fluid and the extracted gas,we use a thermodynamic approach based on static headspace gas chromatography technique to calculate the partition coefficients of 47 kinds of light hydrocarbons compounds between nC5 and nC8 in two kinds of oil-based mud-air systems,and reconstruct the original formation fluid composition under thermodynamic equilibrium.The oil-based drilling mud has little effect on the formation fluid compositions in the range of nC5-nC8(less than 1%for low-toxicity oil-based mud and less than 10%for oil-based mud).For most light hydrocarbon compositions,the partition coefficients obtained by vapor phase calibration and the direct quantitative methods have errors of less than 10%,and the partition coefficients obtained by direct quantitative method are more accurate.The reconstructed compositions of the two kinds of crude oil have match degrees of 91%and 89%with their real compositions,proving the feasibility and accuracy of reconstructing the composition of original formation fluid by using partition coefficients of light hydrocarbon compositions between nC5 and nC8.
基金FCT for her Ph.D grant(SFRH/BD/88334/2012).Thanks are due to Aveiro University and to FCT/MEC for the-nancial support to QOPNA(FCT UID/QUI/00062/2013),CICECO-Aveiro Institute of Materials(FCT UID/CTM/50011/2013),CESAM(FCT UID/MAR/LA0017/2013)and CQE(FCT UID/QUI/0100/2013)research units,through national funds and where applicable co-nanced by the FEDER,within the PT2020 Partnership Agreement.
文摘Among the several types of inorganic nanoparticles available,silica nanoparticles(SNP)have earned their relevance in biological applications namely,as bioimaging agents.In fact,uorescent SNP(FSNP)have been explored in this-eld as protective nanocarriers,overcoming some limitations presented by conventional organic dyes such as high photobleaching rates.A crucial aspect on the use of uorescent SNP relates to their surface properties,since it determines the extent of interaction between nanoparticles and biological systems,namely in terms of colloidal stability in water,cellular recognition and internalization,tracking,biodistribution and speci-city,among others.Therefore,it is imperative to understand the mechanisms underlying the interaction between biosystems and the SNP surfaces,making surface functionalization a relevant step in order to take full advantage of particle properties.The versatility of the surface chemistry on silica platforms,together with the intrinsic hydrophilicity and biocompatibility,make these systems suitable for bioimaging applications,such as those mentioned in this review.
文摘Zwitterionic polymers are known to interact with cells and have been shown to reveal cancer cell specificity.In this work,the importance of the chemistry of the polymer backbone for the cellular specificity of amino-acid-derived polyzwitterions is demonstrated.A series of glutamic acid(Glu)-based vinyl monomers(i.e.,an acrylate,a methacrylate,an acrylamide,and a methacrylamide)were prepared and used for reversible addition-fragmentation chain-transfer(RAFT)polymerisation,yielding defined polymers with narrow size distribution(Ð<1.3).All Glu-functionalised,zwitterionic polymers revealed high cytocompatibility;however,differences in cellular association and specificity were observed.In particular,the methacrylamide-derived polymers showed high association with both,breast cancer cells and non-cancerous dendritic cells and,consequently,lack specificity.In contrast,high specificity to only breast cancer cells was observed for polyacrylates,-methacrylates,and-acrylamides.Detailed analysis of the polymers revealed differences in hydrophobicity,zeta potential,and potential side chain hydrolysis,which are impacted by the polymer backbone and might be responsible for the altered the cell association of these polymers.It is shown that a slightly negative net charge is preferred over a neutral charge to retain cell specificity.This was also confirmed by association experiments in the presence of competitive amino acid transporter substrates.The affinity of slightly negatively charged Glu-derived polymers to the xCT Glu/cystine cell membrane antiporter was found to be higher than that of neutrally charged polymers.Our results emphasise the importance of the polymer backbone for the design of cell-specific polymers.This study further highlights the potential to tailor amino-acid-derived zwitterionic materials beyond their side chain functionality.
基金MMwould like to thank FondsWetenschappelijk Onderzoek(FWO)for financial support(SB PhD fellow at FWO,Grant No.3SB5619)AM has also received funding from Fonds Wetenschappelijk Onderzoek(Grant No.12Z2918N).
文摘Background:Nowadays,a wide range of wound dressings is already commercially available.The selection of the dressing is of paramount importance as inappropriate wound management and dressing selection can delay the wound healing process.Not only can this be distressing for the patient,but it can also contribute to complications such as maceration and subsequent infection.Many researchers are targeting the design of dressings with superior properties over existing commercial dressings.However,reported results in the state-of-the-art are rarely benchmarked against commercial dressings.The aim of this study was to determine several characteristics of a large variety of the most frequently used commercial wound dressings,providing an overview for both practitioners and researchers.Methods:For this comparative study,11 frequently used commercial wound dressings were selected,representing the different types.The morphology was studied using scanning electron microscopy.The dressings were characterized in terms of swelling capacity(water,phosphate buffered saline and simulated wound fluid),moisture vapour transmission rate(MVTR)and moisture uptake capacity(via dynamic vapour sorption)as well as mechanical properties using tensile testing and texturometry.Results:The selected dressings showed distinctive morphological differences(fibrous,porous and/or gel)which was reflected in the different properties.Indeed,the swelling capacities ranged between 1.5 and 23.2 g/g(water),2.1 and 17.6 g/g(phosphate buffered saline)or 2.9 and 20.8 g/g(simulated wound fluid).The swelling capacity of the dressings in water increased even further upon freeze-drying,due to the formation of pores.The MVTR values varied between 40 and 930 g/m^(2)/24 h.The maximal moisture uptake capacity varied between 5.8%and 105.7%at 95%relative humidity.Some commercial dressings exhibited a superior mechanical strength,due to either being hydrophobic or multi-layered.Conclusions:The present work not only offers insight into a valuable toolbox of suitable wound dressing characterization techniques,but also provides an extensive landscaping of commercial dressings along with their physico-chemical properties,obtained through reproducible experimen-tal protocols.Furthermore,it ensures appropriate benchmark values for commercial dressings in all forthcoming studies and could aid researchers with the development of novel modern wound dressings.The tested dressings either exhibited a high strength or a high swelling capacity,suggesting that there is still a strong potential in the wound dressings market for dressings that possess both.
