Elimination de la matière organique biodégradable par ultrafiltration

Les installations de production de la Compagnie des Eaux de banlieue (CEB) au Mont Valérien traitent l'eau de Seine en aval de Paris sur 2 filières de potabilisation comprenant pour la première (50 000 m3/J) une préozonation, une coagulation au sels d'Aluminium (Aqualenc), une décantation (super pulsator Degrémont), une filtration sur sable, une ozonation, une filtration sur charbon actif en grains (CAG) et une désinfection finale au bioxyde de chlore, et pour la deuxième, une filtration lente sur sable (80 000 m3/j) dite filtration "Chabale".Dans le cadre du remplacement de la filière "Chabale", une unité de démonstration (8 m3/h) eomprenaut une addition de charbon actif en poudre (CAP) avant ultrafiltration sur membrane a été mise en route.Dans cette étude, une comparaison du traitement conventionnel physico-chimique de l'usine et du nouveau procédé d'ultrafiltration a été effectuée. Pour cela, un suivi du carbone organique total et une évaluation du potentiel de reviviscence ont été réalisés en différents points des chaînes de traitement. La matière organique biodégradable (MOB) a été mesurée par la méthode Werner (1980).Les premiers résultats montrent :- l'élimination des MOB est comparable pour les différents procédés;- toutefois, la nature des MOB est sensiblement affectée à chaque type de traitement (ozonation, addition de CAP, filtration sur sable ou sur CAG)."Compagnie des Eaux de Banlieue" water facilities located at the Mont-Valérien treat the Seine river water downstream Paris. A first facility (5000 m3/day) includes the following processes : preozonation, coagulation, settling, sand filtration, postozonalion, GAC filtration and a final desinfection (CIO2). A second one consists in a biological sand filtration (80000 m3/day). An ultrafiltration demonstration plant including a CAP addition into the recirculation loop is currently tested on a small scale (8 m3/h) to compare the conventional treatments with new ultrafiltration process.In this study, the TOC removal as well as the biodegradable organic matter (BOM) removal are evaluated on the different processes. The BOM has been assessed by the Werner methodology (1980).During the cool season (october-january) all the biodegradable organic matter were removed by the clarification process (preozonation + coagulation decantation + sand filtration). More than 90 % of the BOM were also removed by the ultrafiltration demonstration plant (including granular activated carbon) although the addition of preozonation slightly increases the effluent BOM concentrations and modifies its composition. 80 % of the dissolved organic compounds were removed by the preozonation + ultrafiltration + powder treatment line. This performance should be compared with the 70 % removal obtained with conventional treatments.This study demonstrate that the combination 03 + UF + CAP can advantageously replace traditional treatment such as preozonation + coagulation clarification + ozonation + granular activated carbon + desinfection

Surface Texturization of Breast Implants Impacts Extracellular Matrix and Inflammatory Gene Expression in Asymptomatic Capsules:

Background: Texturing processes have been designed to improve biocompatibility and mechanical anchoring of breast implants. However, a high degree of texturing has been associated with severe abnormalities. In this study, the authors aimed to determine whether implant surface topography could also affect physiology of asymptomatic capsules. Methods: The authors collected topographic measurements from 17 different breast implant devices by interferometry and radiographic microtomography. Morphologic structures were analyzed statistically to obtain a robust breast implant surface classification. The authors obtained three topographic categories of textured implants (i.e., “peak and valleys,” “open cavities,” and “semiopened cavities”) based on the cross-sectional aspects. The authors simultaneously collected 31 Baker grade I capsules, sorted them according to the new classification, established their molecular profile, and examined the tissue organization. Results: Each of the categories showed distinct expression patterns of genes associated with the extracellular matrix (Timp and Mmp members) and inflammatory response (Saa1, Tnsf11, and Il8), despite originating from healthy capsules. In addition, slight variations were observed in the organization of capsular tissues at the histologic level. Conclusions: The authors combined a novel surface implant classification system and gene profiling analysis to show that implant surface topography is a bioactive cue that can trigger gene expression changes in surrounding tissue, even in Baker grade I capsules. The authors’ new classification system avoids confusion regarding the word “texture,” and could be transposed to implant ranges of every manufacturer. This new classification could prove useful in studies on potential links between specific texturizations and the incidence of certain breast-implant associated complications

Effect of laser treatment on the attachment and viability of mesenchymal stem cell responses on shape memory NiTi alloy

The objectives of this study were to investigate the effect of laser-induced surface features on the morphology, attachment and viability of mesenchymal stem cells (MSCs) at different periods of time, and to evaluate the biocompatibility of different zones: laser-melted zone (MZ), heat-affected zone (HAZ) and base metal (BM) in laser-treated NiTi alloy. The surface morphology and composition were studied by scanning electron microscope (SEM) and X-ray photoemission spectroscopy (XPS), respectively. The cell morphology was examined by SEM while the cell counting and viability measurements were done by hemocytometer and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The results indicated that the laser-induced surface features, such as surface roughening, presence of anisotropic dendritic pattern and complete surface Ni oxidation were beneficial to improve the biocompatibility of NiTi as evidenced by the highest cell attachment (4 days of culture) and viability (7 days of culture) found in the MZ. The biocompatibility of the MZ was the best, followed by the BM with the HAZ being the worst. The defective and porous oxide layer as well as the coarse grained structure might attribute to the inferior cell attachment (4 days of culture) and viability (7 days of culture) on the HAZ compared with the BM which has similar surface morphology. © 2014 Elsevier B.V

Stem Cells for Huntington's Disease (SC4HD): An International Consortium to Facilitate Stem Cell-Based Therapy for Huntington's Disease

Huntington's disease (HD) research is entering an exciting phase, with new approaches such as huntingtin lowering strategies and cell therapies on the horizon. Technological advances to direct the differentiation of stem cells to desired neural types have opened new strategies for restoring damaged neuronal circuits in HD. However, challenges remain in the implementation of cell therapy approaches for patients suffering from HD. Cell therapies, together with other invasive approaches including allele specific oligonucleotides (ASOs) and viral delivery of huntingtin-lowering agents, require direct delivery of the therapeutic agents locally into the brain or cerebrospinal fluid. Delivering substances directly into the brain is complex and presents multiple challenges, including those related to regulatory requirements, safety and efficacy, surgical instrumentation, trial design, patient profiles, and selection of suitable and sensitive primary and secondary outcomes. In addition, production of clinical grade cell-based medicinal products also requires adherence to regulatory standards with extensive quality control of the protocols and cell products across different laboratories and production centers. Currently, there is no consensus on how best to address these challenges. Here we describe the formation of Stem Cells For Huntington's Disease (SC4HD: https://www.sc4hd.org/), a network of researchers and clinicians working to develop guidance and greater standardization for the HD field for stem cell based transplantation therapy for HD with a mission to work to develop criteria and guidance for development of a neural intra-cerebral stem cell-based therapy for HD

Development of a portfolio of learning for postgraduate family medicine training in South Africa: a Delphi study

<p>Abstract</p> <p>Background</p> <p>Within the 52 health districts in South Africa, the family physician is seen as the clinical leader within a multi-professional district health team. Family physicians must be competent to meet 90% of the health needs of the communities in their districts. The eight university departments of Family Medicine have identified five unit standards, broken down into 85 training outcomes, for postgraduate training. The family medicine registrar must prove at the end of training that all the required training outcomes have been attained. District health managers must be assured that the family physician is competent to deliver the expected service. The Colleges of Medicine of South Africa (CMSA) require a portfolio to be submitted as part of the uniform assessment of all registrars applying to write the national fellowship examinations. This study aimed to achieve a consensus on the contents and principles of the first national portfolio for use in family medicine training in South Africa.</p> <p>Methods</p> <p>A workshop held at the WONCA Africa Regional Conference in 2009 explored the purpose and broad contents of the portfolio. The 85 training outcomes, ideas from the WONCA workshop, the literature, and existing portfolios in the various universities were used to develop a questionnaire that was tested for content validity by a panel of 31 experts in family medicine in South Africa, via the Delphi technique in four rounds. Eighty five content items (national learning outcomes) and 27 principles were tested. Consensus was defined as 70% agreement. For those items that the panel thought should be included, they were also asked how to provide evidence for the specific item in the portfolio, and how to assess that evidence.</p> <p>Results</p> <p>Consensus was reached on 61 of the 85 national learning outcomes. The panel recommended that 50 be assessed by the portfolio and 11 should not be. No consensus could be reached on the remaining 24 outcomes and these were also omitted from the portfolio. The panel recommended that various types of evidence be included in the portfolio. The panel supported 26 of the 27 principles, but could not reach consensus on whether the portfolio should reflect on the relationship between the supervisor and registrar.</p> <p>Conclusion</p> <p>A portfolio was developed and distributed to the eight departments of Family Medicine in South Africa, and the CMSA, to be further tested in implementation.</p

Surface modification of starch based biomaterials by oxygen plasma or UV-irradiation

Radiation is widely used in biomaterials science for surface modification and sterilization. Herein, we describe the use of plasma and UV-irradiation to improve the biocompatibility of different starch-based blends in terms of cell adhesion and proliferation. Physical and chemical changes, introduced by the used methods, were evaluated by complementary techniques for surface analysis such as scanning electron microscopy, atomic force microscopy, contact angle analysis and X-ray photoelectron spectroscopy. The effect of the changed surface properties on the adhesion of osteoblast-like cells was studied by a direct contact assay. Generally, both treatments resulted in higher number of cells adhered to the modified surfaces. The importance of the improved biocompatibility resulting from the irradiation methods is further supported by the knowledge that both UV and plasma treatments can be used as cost-effective methods for sterilization of biomedical materials and devices.I. P. thanks the FCT for providing her a postdoctoral scholarship (SFRH/BPD/8491/2002). This work was partially supported by FCT, through funds from the POCTI and/or FEDER programs, The European Union funded STREP Project HIPPOCRATES (NNM-3-CT-2003-505758) and the European NoE EXPERTISSUES (NMP3-CT-2004-500283)

Biological evaluation of alginate-based hydrogels, with antimicrobial features by Ce(III) incorporation, as vehicles for a bone substitute

In this work three different hydrogels were developed to associate, as vehicles, with the synthetic bone substitute GR-HA. One based on an alginate matrix (Alg); a second on a mixture of alginate and chitosan (Alg/Ch); and a third on alginate and hyaluronate (Alg/HA), using Ca2+ ions as cross-linking agents. The hydrogels, as well as the respective injectable bone substitutes (IBSs), were fully characterized from the physical-chemical point of view. Weight change studies proved that all hydrogels were able to swell and degrade within 72 hours at pH 7.4 and 4.0, being Alg/HA the hydrogel with the highest degradation rate (80%). Rheology studies demonstrated that all hydrogels are non-Newtonian viscoelastic fluids, and injectability tests showed that IBSs presented low maximum extrusion forces, as well as quite stable average forces. In conclusion, the studied hydrogels present the necessary features to be successfully used as vehicles of GR-HA, particularly the hydrogel Alg/HA.The authors would like to acknowledge the financial support from FCT (Fundacao para a Ciencia e a Tecnologia) through the grant SFRH/BD/76237/2011 and project ENMED/0002/2010, from FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade-under the project PEst-C/EME/UI0285/2011, as well as to the project I&DT BIOMAT&CELL n. 1372

Formation of bone-like apatite layer on chitosan fiber mesh scaffolds by a biomimetic spraying process

Bone-like apatite coating of polymeric substrates by means of biomimetic process is a possible way to enhance the bone bonding ability of the materials. The created apatite layer is believed to have an ability to provide a favorable environment for osteoblasts or osteoprogenitor cells. The purpose of this study is to obtain bone-like apatite layer onto chitosan fiber mesh tissue engineering scaffolds, by means of using a simple biomimetic coating process and to determine the influence of this coating on osteoblastic cell responses. Chitosan fiber mesh scaffolds produced by a previously described wet spinning methodology were initially wet with a Bioglass"–water suspension by means of a spraying methodology and then immersed in a simulated body fluid (SBF) mimicking physiological conditions for one week. The formation of apatite layer was observed morphologically by scanning electron microscopy (SEM). As a result of the use of the novel spraying methodology, a fine coating could also be observed penetrating into the pores, that is clearly within the bulk of the scaffolds. Fourier Transform Infrared spectroscopy (FTIRATR), Electron Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) analysis also confirmed the presence of apatite-like layer. A human osteoblast-like cell line (SaOs-2) was used for the direct cell contact assays. After 2 weeks of culture, samples were observed under the SEM. When compared to the control samples (unmodified chitosan fiber mesh scaffolds) the cell population was found to be higher in the Ca–P biomimetic coated scaffolds, which indicates that the levels of cell proliferation on this kind of scaffolds could be enhanced. Furthermore, it was also observed that the cells seeded in the Ca–P coated scaffolds have a more spread and flat morphology, which reveals an improvement on the cell adhesion patterns, phenomena that are always important in processes such as osteoconduction

In vitro studies and preliminary in vivo evaluation of silicified concentrated collagen hydrogels

Hybrid and nanocomposite silicacollagen materials derived from concentrated collagen hydrogels were evaluated in vitro and in vivo to establish their potentialities for biological dressings. Silicification significantly improved the mechanical and thermal stability of the collagen network within the hybrid systems. Nanocomposites were found to favor the metabolic activity of immobilized human dermal fibroblastswhile decreasing the hydrogel contraction. Cell adhesion experiments suggested that in vitro cell behavior was dictated by mechanical properties and surface structure of the scaffold. First-to-date in vivo implantation of bulk hydrogels in subcutaneous sites of rats was performed over the vascular inflammatory period. These materials were colonized and vascularized without inducing strong inflammatory response. These data raise reasonable hope for the future application of silicacollagen biomaterials as biological dressings.Fil: Desimone, Martín Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Hélary, Christophe. Université Pierre et Marie Curie; FranciaFil: Quignard, Sandrine. Université Pierre et Marie Curie; FranciaFil: Rietveld, Ivo B. Universite de Paris; FranciaFil: Bataille, Clement. Université de Versailles Saint-quentin-en-yvelines.; FranciaFil: Copello, Guillermo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Mosser, Gervaise. Université Pierre et Marie Curie; FranciaFil: Giraud Guille, Marie-Madeleine. Université Pierre et Marie Curie; FranciaFil: Livage, Jacques. Université Pierre et Marie Curie; FranciaFil: Meddahi Pellé, Anne. Université de Versailles Saint-quentin-en-yvelines.; FranciaFil: Coradin, Thibaud. Université Pierre et Marie Curie; Franci