40 research outputs found
Cigarette Smoking Effect on Microhardness and Flexural Properties of Denture Base Resins
Objective: To identify the tobacco effect on flexural properties and the microhardness of three acrylic resins. Material and Methods: Three resins were tested: two thermo-polymerizable acrylic resins (RMB 20 and BMS 014) and one autopolymerized acrylic resin. The 3-point bending and microhardness tests were carried out with a universal tensile-compression machine and a micro-Vickers hardness tester. The acrylic resin specimens have been exposed for 21 days to cigarette smoke in a smoking room. Their mechanical strength was compared to unexposed samples. Statistical analysis was performed using the data processing software SPSS Statistics 21.0. Results: The flexural properties of the resins were affected by cigarette smoke only in the case of Major Base 20Âź (drop in strength with p= 0.02; 0.6; 0.7 and in elastic modulus with p= 0.86; 0.74 and 0.85 for Major Base 20Âź, BMS 014Âź and Major RepairÂź). The cigarette smoke affected significantly microhardness for all groups (p<0.001). Conclusion: Cigarette smoking does not affect the flexural properties of the acrylic resin (BMS 014Âź and Major RepairÂź unlike Major Base 20Âź), but it does reduce the microhardness
Nanoparticulate ZrO2/SO42- Catalyst for Biofuel Production
This study reports on the preparation of zirconia coatings based on monodispersed zirconium-oxo-alkoxy (ZOA) nanoparticles for conversion of free fatty acid (FFA) into biofuel. Monodispersed ZOA nanoparticles of 3.6 nm size were prepared by sol-gel method in a rapid micro-mixing reactor with turbulent fluids flow at 20°C. The ZOA nanopowders obtained after precipitation and nanocoatings deposited on glass beads, after subsequent sulfatation, drying and calcinations, show high catalytic activity towards esterification process. The biofuel yield in esterification of palmitic acid in methanol reached 67% (after t=3.5 hours) on nanopowders while it increases to 98% on nonocoatings
Elaboration des nanoparticules d'oxyde de zirconium par voie sol-gel : mise en forme et application pour la synthĂšse de biodiesel
In this work, we have realized novel nanoparticulate catalysts ZrOâ-SOâÂČâ» for biofuel production. We have studied nucleation-growth kinetics of zirconium-oxo-alkoxy (ZOA) nanoparticles in the sol-gel process. The monodispersed nanoparticles of 3.6 nm diameter were realised in a sol-gel reactor with rapid (turbulent) micro-mixing of liquid solutions containing ZNP and HâO in 1-propanol at 20°C. The nanocoatings were realised of stable colloids of ZOA nanoparticles on silica beads along with common powders obtained after precipitation of unstable colloids. The acid ZrOâ-SOâÂČâ»" catalysts were prepared after drying at 80°C, wet impregnation in 0.25 mol.Lâ»Âč aqueous solution of sulfuric acid and subsequent thermal treatment between 500 and 700°C and studied with BET, DTA-DSC, TEM, DRIFT, elemental analysis, DRX and other methods. The catalyst nanocoatings calcinated at 580°C showed strong activity in esterification reaction of palmitic acid in methanol at 65°C, which is about 50 times higher than that of nanopowders, and also possesses the highest stability towards recycling. Tha catalytic performance of catalytic nanocoatings was also confirmed on unedible and waste oils.Actuellement, la stratĂ©gie de la production dâĂ©nergie repose sur les 3 concepts dâĂ©conomie, de rĂ©gĂ©nĂ©ration et dâĂ©cologie. La production de biodiesel sâinsĂšre dans cette thĂ©matique et fait objet de ce travail. Un suivi cinĂ©tique de nuclĂ©ation-croissance est rĂ©alisĂ© sur des nanoparticules monodisperses dâoxo-alcoxydes de zirconium (ZOA). Ces nanoparticules sont prĂ©parĂ©es par voie sol-gel dans un rĂ©acteur Ă T-micro-mĂ©langeur avec deux flux turbulents de ZNP et c dans 1-propanol Ă 20°C. Les nanodĂ©pĂŽts des nanoparticules de ZOA ont Ă©tĂ© rĂ©alisĂ©s sur des substrats en silice et comparĂ©s aux nanopoudres rĂ©cupĂ©rĂ©es aprĂšs lâinduction du sol de ZOA. Les nanodĂ©pĂŽts et les poudres subissent un sĂ©chage Ă 80°C puis une imprĂ©gnation humide dans une solution aqueuse de 0,25 mol.Lâ»Âč de HâSOâ. Nous obtenons ainsi les nanodĂ©pĂŽts catalytiques aprĂšs une calcination Ă des tempĂ©ratures comprises entre 500 et 700°C sous Oâ. Les techniques de BET, ATG-ATD, MET, DRIFT, analyse Ă©lĂ©mentaire et DRX sont dĂ©ployĂ©es pour caractĂ©riser ces catalyseurs. Les cinĂ©tiques du processus dâestĂ©rification et de transestĂ©rification ont Ă©tĂ© Ă©tudiĂ©es en fonction des conditions de la prĂ©parartion des catalyseurs nanostructurĂ©s. Les nanodĂ©pĂŽts catalytiques acides de ZrOâ-SOâÂČâ» possĂšdent une activitĂ© catalytique 50 fois plus Ă©levĂ©e que celle des nanopoudres dans la rĂ©action dâestĂ©rification de lâacide palmitique dans le mĂ©thanol Ă 65°C. Les nanodĂ©pĂŽts calcinĂ©s Ă 580°C ont la meilleure stabilitĂ© vis Ă vis des essais de recyclage. LâactivitĂ© catalytique des nanodĂ©pĂŽts est aussi valable avec dâautres charges dont la composition est similaire Ă celle des huiles non-comestibles puis celle des dĂ©chets gras
Elaboration of zirconium oxide Nanoparticles : Catalyst Preparation and Application in Biofuel Synthesis
Actuellement, la stratĂ©gie de la production dâĂ©nergie repose sur les 3 concepts dâĂ©conomie, de rĂ©gĂ©nĂ©ration et dâĂ©cologie. La production de biodiesel sâinsĂšre dans cette thĂ©matique et fait objet de ce travail. Un suivi cinĂ©tique de nuclĂ©ation-croissance est rĂ©alisĂ© sur des nanoparticules monodisperses dâoxo-alcoxydes de zirconium (ZOA). Ces nanoparticules sont prĂ©parĂ©es par voie sol-gel dans un rĂ©acteur Ă T-micro-mĂ©langeur avec deux flux turbulents de ZNP et c dans 1-propanol Ă 20°C. Les nanodĂ©pĂŽts des nanoparticules de ZOA ont Ă©tĂ© rĂ©alisĂ©s sur des substrats en silice et comparĂ©s aux nanopoudres rĂ©cupĂ©rĂ©es aprĂšs lâinduction du sol de ZOA. Les nanodĂ©pĂŽts et les poudres subissent un sĂ©chage Ă 80°C puis une imprĂ©gnation humide dans une solution aqueuse de 0,25 mol.Lâ»Âč de HâSOâ. Nous obtenons ainsi les nanodĂ©pĂŽts catalytiques aprĂšs une calcination Ă des tempĂ©ratures comprises entre 500 et 700°C sous Oâ. Les techniques de BET, ATG-ATD, MET, DRIFT, analyse Ă©lĂ©mentaire et DRX sont dĂ©ployĂ©es pour caractĂ©riser ces catalyseurs. Les cinĂ©tiques du processus dâestĂ©rification et de transestĂ©rification ont Ă©tĂ© Ă©tudiĂ©es en fonction des conditions de la prĂ©parartion des catalyseurs nanostructurĂ©s. Les nanodĂ©pĂŽts catalytiques acides de ZrOâ-SOâÂČâ» possĂšdent une activitĂ© catalytique 50 fois plus Ă©levĂ©e que celle des nanopoudres dans la rĂ©action dâestĂ©rification de lâacide palmitique dans le mĂ©thanol Ă 65°C. Les nanodĂ©pĂŽts calcinĂ©s Ă 580°C ont la meilleure stabilitĂ© vis Ă vis des essais de recyclage. LâactivitĂ© catalytique des nanodĂ©pĂŽts est aussi valable avec dâautres charges dont la composition est similaire Ă celle des huiles non-comestibles puis celle des dĂ©chets gras.In this work, we have realized novel nanoparticulate catalysts ZrOâ-SOâÂČâ» for biofuel production. We have studied nucleation-growth kinetics of zirconium-oxo-alkoxy (ZOA) nanoparticles in the sol-gel process. The monodispersed nanoparticles of 3.6 nm diameter were realised in a sol-gel reactor with rapid (turbulent) micro-mixing of liquid solutions containing ZNP and HâO in 1-propanol at 20°C. The nanocoatings were realised of stable colloids of ZOA nanoparticles on silica beads along with common powders obtained after precipitation of unstable colloids. The acid ZrOâ-SOâÂČâ»" catalysts were prepared after drying at 80°C, wet impregnation in 0.25 mol.Lâ»Âč aqueous solution of sulfuric acid and subsequent thermal treatment between 500 and 700°C and studied with BET, DTA-DSC, TEM, DRIFT, elemental analysis, DRX and other methods. The catalyst nanocoatings calcinated at 580°C showed strong activity in esterification reaction of palmitic acid in methanol at 65°C, which is about 50 times higher than that of nanopowders, and also possesses the highest stability towards recycling. Tha catalytic performance of catalytic nanocoatings was also confirmed on unedible and waste oils
Functional and phenotypical alterations of plasmacytoid dendritic cells and regulatory T cells in ovarian cancer
Le cancer de lâovaire est immunogĂšne et constitue un bon modĂšle pour Ă©tudier lâimmunitĂ© antitumorale. Nous avons effectuĂ© une Ă©tude comparative et systĂ©matique de la frĂ©quence, du phĂ©notype, de la fonction et de lâimpact sur la survie des cellules dendritiques plasmacytoĂŻdes (pDC) et des lymphocytes T rĂ©gulateurs (Treg) dans le sang, lâascite et la tumeur. Nous avons observĂ© que les pDC sâaccumulent dans les ascites et sont prĂ©sentes dans certaines tumeurs alors quâelles sont profondĂ©ment dĂ©plĂ©tĂ©es dans le sang des patientes. La prĂ©sence de pDC associĂ©es aux tumeurs (TApDC) est un facteur pronostique indĂ©pendant associĂ© Ă une survie sans progression (SSP) plus courte. De plus, les TApDC, mais pas les pDC dâascite, sont altĂ©rĂ©es dans leur fonction innĂ©e principale de production dâIFN-α en rĂ©ponse aux TLR ligands in vitro et induisent le dĂ©veloppement de lymphocytes T CD4+ producteurs dâIL-10 responsables dâune tolĂ©rance immune favorisant la progression tumorale. Les Treg sâaccumulent dans les ascites et les tumeurs de lâovaire mais leur taux dans le sang est comparable aux donneurs sains. Leur accumulation dans les tumeurs et non dans les ascites est un facteur pronostique indĂ©pendant associĂ© Ă une SSP plus longue. Les TATreg ont un phĂ©notype activĂ© et inhibent la production dâIL-10 par les lymphocytes T CD4+ conventionnels associĂ©s aux tumeurs. De façon intĂ©ressante, les patientes dont les tumeurs augmentent lâinfiltration par les Treg Foxp3+ aprĂšs chimiothĂ©rapie nĂ©oadjuvante ont une rechute retardĂ©e suggĂ©rant quâen plus dâun effet antitumoral direct, la chimiothĂ©rapie induit une rĂ©ponse immuneOvarian cancer (OC) is an immunogenic disease and represents a good model for studying antitumoral immunity. We performed a systematic comparison between plasmacytoid dendritic cells (pDC) and regulatory T cells (Treg) in blood, ascites, and tumors in term of frequencies, phenotypes, functions, and impact on outcome of OC patients. We found that pDC accumulate in ascites and are present in some tumors whereas they are profoundly depleted in patientsâ blood. Their presence within tumors (but not ascites) is deleterious because associated with early relapse of OC patients. Moreover, Tumor associated pDC (TApDC) but not ascite pDC were altered in their innate function, i.e. the production of IFN-α in response to TLR ligands in vitro, and they induce the development of IL-10+ CD4+T cells. All these results suggest that TApDC but not ascite pDC induce immune tolerance allowing cancer progression. Treg accumulate in ascites and tumors but their levels in patientsâ blood were not increased. Their accumulation in tumors, but not ascites, was an independent prognostic factor associated with delayed relapse. TATreg showed an activated phenotype and inhibit IL-10 production by CD4+conventional TAT cells. Interestingly, patients whose tumor infiltration by Foxp3+ Treg is increased after neoadjuvant chemotherapy showed delayed relapse suggesting that chemotherapy, in addition to its direct antitumoral effect, induces an immune respons
AltĂ©rations fonctionnelles et phĂ©notypiques des cellules dendritiques plasmacytoĂŻdes et des lymphocytes T rĂ©gulateurs dans le cancer de lâovaire
Ovarian cancer (OC) is an immunogenic disease and represents a good model for studying antitumoral immunity. We performed a systematic comparison between plasmacytoid dendritic cells (pDC) and regulatory T cells (Treg) in blood, ascites, and tumors in term of frequencies, phenotypes, functions, and impact on outcome of OC patients. We found that pDC accumulate in ascites and are present in some tumors whereas they are profoundly depleted in patientsâ blood. Their presence within tumors (but not ascites) is deleterious because associated with early relapse of OC patients. Moreover, Tumor associated pDC (TApDC) but not ascite pDC were altered in their innate function, i.e. the production of IFN-α in response to TLR ligands in vitro, and they induce the development of IL-10+ CD4+T cells. All these results suggest that TApDC but not ascite pDC induce immune tolerance allowing cancer progression. Treg accumulate in ascites and tumors but their levels in patientsâ blood were not increased. Their accumulation in tumors, but not ascites, was an independent prognostic factor associated with delayed relapse. TATreg showed an activated phenotype and inhibit IL-10 production by CD4+conventional TAT cells. Interestingly, patients whose tumor infiltration by Foxp3+ Treg is increased after neoadjuvant chemotherapy showed delayed relapse suggesting that chemotherapy, in addition to its direct antitumoral effect, induces an immune responseLe cancer de lâovaire est immunogĂšne et constitue un bon modĂšle pour Ă©tudier lâimmunitĂ© antitumorale. Nous avons effectuĂ© une Ă©tude comparative et systĂ©matique de la frĂ©quence, du phĂ©notype, de la fonction et de lâimpact sur la survie des cellules dendritiques plasmacytoĂŻdes (pDC) et des lymphocytes T rĂ©gulateurs (Treg) dans le sang, lâascite et la tumeur. Nous avons observĂ© que les pDC sâaccumulent dans les ascites et sont prĂ©sentes dans certaines tumeurs alors quâelles sont profondĂ©ment dĂ©plĂ©tĂ©es dans le sang des patientes. La prĂ©sence de pDC associĂ©es aux tumeurs (TApDC) est un facteur pronostique indĂ©pendant associĂ© Ă une survie sans progression (SSP) plus courte. De plus, les TApDC, mais pas les pDC dâascite, sont altĂ©rĂ©es dans leur fonction innĂ©e principale de production dâIFN-α en rĂ©ponse aux TLR ligands in vitro et induisent le dĂ©veloppement de lymphocytes T CD4+ producteurs dâIL-10 responsables dâune tolĂ©rance immune favorisant la progression tumorale. Les Treg sâaccumulent dans les ascites et les tumeurs de lâovaire mais leur taux dans le sang est comparable aux donneurs sains. Leur accumulation dans les tumeurs et non dans les ascites est un facteur pronostique indĂ©pendant associĂ© Ă une SSP plus longue. Les TATreg ont un phĂ©notype activĂ© et inhibent la production dâIL-10 par les lymphocytes T CD4+ conventionnels associĂ©s aux tumeurs. De façon intĂ©ressante, les patientes dont les tumeurs augmentent lâinfiltration par les Treg Foxp3+ aprĂšs chimiothĂ©rapie nĂ©oadjuvante ont une rechute retardĂ©e suggĂ©rant quâen plus dâun effet antitumoral direct, la chimiothĂ©rapie induit une rĂ©ponse immun
Pathogenesis of ovarian cancer
Epithelial ovarian cancer (EOC) is a heterogeneous disease with five histotypes: serous (high-grade and low-grade), endometrioid, clear cell and mucinous carcinoma. New evidences suggest that the majority of EOC are of extra-ovarian origin. We used next-generation sequencing to investigate the cell of origin of high-grade serous ovarian carcinoma (HGSOC) and mucinous ovarian carcinoma (MOC). We analyzed exome-wide sequence and structural analyses of multiple tumor samples from five individuals with advanced stage sporadic HGSOC. Our results suggest that ovarian cancer is a disease of the fallopian tubes, with the development of p53 signatures and serous tubal intraepithelial carcinoma as early events. The subsequent formation of a cancer in the ovaries represents a seeding event from a primary tumor in the fallopian tube that already contains sequence and structural alterations in key driver genes, including TP53, PI3K pathway, and BRCA1/BRCA2 genes. Our work could have implication for screening and early diagnosis of HGSOC. In a separate work, we used unsupervised clustering of gene-expression profile of different histotype of ovarian tumors, their eutopic tissues (ovarian surface epithelium and fallopian tube) and single-cell RNA-sequencing of primordial germ cells (PGCs). We observed that mucinous ovarian tumors (borderline and carcinoma) cluster more closely to PGCs than their eutopic tissue of origin. Our work brings a new and plausible explanation of the clinical and epidemiologic characteristics of MOC and could help into developing new target therapies for this rare and chemoresistant tumor