50 research outputs found

    Sugerencias para introducir los biocombustibles en la norma nacional vigente para la determinación del poder calorífico

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    La energía que realmente podrá utilizarse de la biomasa, depende de parámetros concretos y de fácil medida, tales como el poder calorífico y la humedad. Una correcta elección de la técnica para determinar estas variables, hace fiables sus mediciones. En este trabajo se hace una revisión sobre calorímetros, se presenta la metodología para determinar el poder calorífico de biocombustibles, según la técnica definida por la norma IRAM 17016, haciéndose sugerencias para aclarar algunos conceptos. Después de varios ensayos realizados siguiendo el procedimiento establecido en la norma, se encontraron ciertas dificultades y carencias, por lo que resultó necesario proponer una modificación y actualización. Entre los inconvenientes surgidos durante las experiencias, se mencionan: una insuficiente descripción y escasa información gráfica, el sistema de medición de temperaturas no es claro y falta agregar esquemas del calorímetro con cada una de sus partes, entre otros. Por último, se comparó la Norma IRAM 17016 con últimas normas europeas con el fin de proponer una actualización que facilite la utilización y aprovechamiento de la misma.The energy that actually be used from biomass, depends on specific parameters and easy to measure, such as the calorific power and moisture content. A correct choice of technique for determining these variables makes its reliable measurements. This paper presents a review of calorimeters, and a methodology is presented to determine the heating value of biofuels according to the technique defined by the IRAM 17016 standard, making suggestions to clarify some concepts. After several trials following the procedure laid down in the standard, certain difficulties and shortcomings were found, so it was necessary to propose a modification and updating. Among the problems encountered during the experiments, are mentioned: insufficient description and graphical information sparse, the temperature measurement system is unclear and need to add calorimeter schemes with each of its parts, among other problems. Finally, the IRAM 17016 was compared to latest European standards in order to propose an update to facilitate the use and exploitation of it.Tema 6: Energía eólica, geotermia, biomasa y otras energías no convencionales.Facultad de Arquitectura y Urbanism

    Sugerencias para introducir los biocombustibles en la norma nacional vigente para la determinación del poder calorífico

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    La energía que realmente podrá utilizarse de la biomasa, depende de parámetros concretos y de fácil medida, tales como el poder calorífico y la humedad. Una correcta elección de la técnica para determinar estas variables, hace fiables sus mediciones. En este trabajo se hace una revisión sobre calorímetros, se presenta la metodología para determinar el poder calorífico de biocombustibles, según la técnica definida por la norma IRAM 17016, haciéndose sugerencias para aclarar algunos conceptos. Después de varios ensayos realizados siguiendo el procedimiento establecido en la norma, se encontraron ciertas dificultades y carencias, por lo que resultó necesario proponer una modificación y actualización. Entre los inconvenientes surgidos durante las experiencias, se mencionan: una insuficiente descripción y escasa información gráfica, el sistema de medición de temperaturas no es claro y falta agregar esquemas del calorímetro con cada una de sus partes, entre otros. Por último, se comparó la Norma IRAM 17016 con últimas normas europeas con el fin de proponer una actualización que facilite la utilización y aprovechamiento de la misma.The energy that actually be used from biomass, depends on specific parameters and easy to measure, such as the calorific power and moisture content. A correct choice of technique for determining these variables makes its reliable measurements. This paper presents a review of calorimeters, and a methodology is presented to determine the heating value of biofuels according to the technique defined by the IRAM 17016 standard, making suggestions to clarify some concepts. After several trials following the procedure laid down in the standard, certain difficulties and shortcomings were found, so it was necessary to propose a modification and updating. Among the problems encountered during the experiments, are mentioned: insufficient description and graphical information sparse, the temperature measurement system is unclear and need to add calorimeter schemes with each of its parts, among other problems. Finally, the IRAM 17016 was compared to latest European standards in order to propose an update to facilitate the use and exploitation of it.Tema 6: Energía eólica, geotermia, biomasa y otras energías no convencionales.Facultad de Arquitectura y Urbanism

    Sugerencias para introducir los biocombustibles en la norma nacional vigente para la determinación del poder calorífico

    Get PDF
    La energía que realmente podrá utilizarse de la biomasa, depende de parámetros concretos y de fácil medida, tales como el poder calorífico y la humedad. Una correcta elección de la técnica para determinar estas variables, hace fiables sus mediciones. En este trabajo se hace una revisión sobre calorímetros, se presenta la metodología para determinar el poder calorífico de biocombustibles, según la técnica definida por la norma IRAM 17016, haciéndose sugerencias para aclarar algunos conceptos. Después de varios ensayos realizados siguiendo el procedimiento establecido en la norma, se encontraron ciertas dificultades y carencias, por lo que resultó necesario proponer una modificación y actualización. Entre los inconvenientes surgidos durante las experiencias, se mencionan: una insuficiente descripción y escasa información gráfica, el sistema de medición de temperaturas no es claro y falta agregar esquemas del calorímetro con cada una de sus partes, entre otros. Por último, se comparó la Norma IRAM 17016 con últimas normas europeas con el fin de proponer una actualización que facilite la utilización y aprovechamiento de la misma.The energy that actually be used from biomass, depends on specific parameters and easy to measure, such as the calorific power and moisture content. A correct choice of technique for determining these variables makes its reliable measurements. This paper presents a review of calorimeters, and a methodology is presented to determine the heating value of biofuels according to the technique defined by the IRAM 17016 standard, making suggestions to clarify some concepts. After several trials following the procedure laid down in the standard, certain difficulties and shortcomings were found, so it was necessary to propose a modification and updating. Among the problems encountered during the experiments, are mentioned: insufficient description and graphical information sparse, the temperature measurement system is unclear and need to add calorimeter schemes with each of its parts, among other problems. Finally, the IRAM 17016 was compared to latest European standards in order to propose an update to facilitate the use and exploitation of it.Tema 6: Energía eólica, geotermia, biomasa y otras energías no convencionales.Facultad de Arquitectura y Urbanism

    Primary antiphospholipid syndrome evolving into systemic lupus erythematosus: may antinucleosome antibodies be predictive?

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    Objective: It was reported by several groups that patients diagnosed as primary antiphospholipid syndrome (PAPS) had developed a full-blown systemic lupus erythematosus (SLE) even after many years of follow-up. Little is known about clinical and/or serological factors that may help predict such evolution. Antinucleosome antibodies (anti-NCS) were described to appear in early stages of SLE, in particular before anti-dsDNA antibodies. The aim of the study is to evaluate the prevalence of anti-NCS in a large cohort of PAPS patients. Methods: IgG and IgM anti-NCS antibodies were detected using a home made assay with H1-stripped chromatin as antigen. Sera from 106 PAPS patients were tested; 52 of them were also tested during the follow-up, at least 2 years apart form the basal sample. Results: Medium-high titre anti-NCS were found in nearly half of the patients (49/106, 46%), more frequently in those presenting features of "lupus like disease". Most of patients displayed an unchanged pattern of anti-NCS over time. We describe three cases of PAPS patients that developed SLE after many years of follow-up; high titre and low titre anti-NCS were present in two and one of them respectively several years before evolving into SLE. Conclusions: A significant proportion of PAPS patients displayed medium-high titre anti-NCS, suggesting that the autoimmune response against chromatin may be a relevant event not only in patients with SLE. Further studies are warranted to explore the predictive value of anti-NCS with respect to the evolution from PAPS to SLE

    The Fire and Tree Mortality Database, for Empirical Modeling of Individual Tree Mortality After Fire

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    Wildland fires have a multitude of ecological effects in forests, woodlands, and savannas across the globe. A major focus of past research has been on tree mortality from fire, as trees provide a vast range of biological services. We assembled a database of individual-tree records from prescribed fires and wildfires in the United States. The Fire and Tree Mortality (FTM) database includes records from 164,293 individual trees with records of fire injury (crown scorch, bole char, etc.), tree diameter, and either mortality or top-kill up to ten years post-fire. Data span 142 species and 62 genera, from 409 fires occurring from 1981-2016. Additional variables such as insect attack are included when available. The FTM database can be used to evaluate individual fire-caused mortality models for pre-fire planning and post-fire decision support, to develop improved models, and to explore general patterns of individual fire-induced tree death. The database can also be used to identify knowledge gaps that could be addressed in future research

    Seasonal influenza vaccination of healthcare workers : Systematic review of qualitative evidence

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    Background Most countries recommend that healthcare workers (HCWs) are vaccinated seasonally against influenza in order to protect themselves and patients. However, in many cases coverage remains low. A range of strategies have been implemented to increase uptake. Qualitative evidence can help in understanding the context of interventions, including why interventions may fail to achieve the desired effect. This study aimed to synthesise evidence on HCWs’ perceptions and experiences of vaccination for seasonal influenza. Methods Systematic review of qualitative evidence. We searched MEDLINE, EMBASE and CINAHL and included English-language studies which reported substantive qualitative data on the vaccination of HCWs for seasonal influenza. Findings were synthesised thematically. Results Twenty-five studies were included in the review. HCWs may be motivated to accept vaccination to protect themselves and their patients against infection. However, a range of beliefs may act as barriers to vaccine uptake, including concerns about side-effects, scepticism about vaccine effectiveness, and the belief that influenza is not a serious illness. HCWs value their autonomy and professional responsibility in making decisions about vaccination. The implementation of interventions to promote vaccination uptake may face barriers both from HCWs’ personal beliefs and from the relationships between management and employees within the targeted organisations. Conclusions HCWs’ vaccination behaviour needs to be understood in the context of HCWs’ relationships with each other, with management and with patients. Interventions to promote vaccination should take into account both the individual beliefs of targeted HCWs and the organisational context within which they are implemented

    How to improve influenza vaccine coverage of healthcare personnel

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    Abstract Influenza causes substantial morbidity and mortality worldwide each year. Healthcare-associated influenza is a frequent event. Health care personnel (HCP) may be the source for infecting patients and may propagate nosocomial outbreaks. All HCP should receive a dose of influenza vaccine each year to protect themselves and others. This commentary will discuss the study recently published in the IJHPR by Nutman and Yoeli which assessed the beliefs and attitudes of HCP in an Israel hospital regarding influenza and the influenza vaccine. Unfortunately, as noted by Nutman and Yoeli in this issue many HCP in Israel choose not to receive influenza immunization and many harbor misconceptions regarding their risk for influenza as well as the benefits of influenza vaccine. We also discuss proven methods to increase acceptance by HCP for receiving an annual influenza vaccine

    STUDY OF THE SOLID STATE OF INDOMETHACIN PARTICLES OBTAINED BY PSEUDO-EMULSION TECHNIQUE

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    INTRODUCTION The dissolution properties of a drug and its release from a solid dosage form have a basic impact on its bioavailability. Solving solubility problems is a major challenge for the pharmaceutical industry with developments of new pharmaceutical products, since nearly half of the active substances are either insoluble or poorly soluble in water and display resistance to being wetted by and dissolved into the fluid in the gastrointestinal tract (Patravale et al., 2004). Since the dissolution rate of a drug is a function of its intrinsic solubility and its particle size, studies with poorly soluble drugs have demonstrated that particle-size reduction to the sub-micron range can lead to an increase in dissolution rate and higher bioavailability. Over the last 10 years, nanoparticle engineering processes have been developed and reported for pharmaceutical applications, such as the nanosuspensions, used to formulate compounds that are insoluble in both water and oils and to reformulate existing drugs to remove toxicologically less favourable excipients (Kesisoglon et al. 2007, Kocbek et al., 2006). In this work we aimed to test the efficiency of the technique of pseudo-emulsion to produce nanoparticles of indomethacin and evaluate how this technique affects the formation of indomethacin polymorphs. Nanoparticles were analyzed by means of size analysis, XRD, DSC, TGA, dissolution test. MATERIALS AND METHODS Indomethacin (Sigma Chemical, USA); Tween 80 (Kock Light Laboratories, LTD, England); Benzalkonium chloride (Carlo Erba, Milano, Italy); Stearic acid (Polichimica, Bologna, Italy); Eudragit\uae RS PO (Rohm Pharma Gmbh, Weiterstedt, Germany); Acetone; Phosphate buffer pH 7.4 ( S\uf6rensen) Preparation of nanoparticles \u2013 Two solutions were prepared separately. An aqueous solution, suitably cooled in an ice bath to prevent temperature increase, contained the surfactant mixture and was stirred using turbo-emulsifier Ultra Turrax T25; the aqueous solution was dropwise added of an organic solution containing indomethacin dissolved in acetone, by means of a peristaltic pump. The emulsion thus formed is left under magnetic and slow stirring for 24 h to allow evaporation of the solvent. Nanoparticles of the drug were recovered by ultra-centrifugation (Alc 4239R-CFC-free). Powder X-ray diffraction (XRD) - To perform X-ray diffractometric analysis a Philips PW3719 diffractometer was used, controlled by a computer. Experimental conditions: Cu K_ radiation (X = 1.78896 A\ub0 ); 40 kV and 30 mA. Scanning interval: 5\u201350◦ 2θ; time per step: l s; graphite monochromator on the diffracted beam. Differential scanning calorimetry - Thermal and thermogravimetric analyses were performed with an automatic thermal analyzer system Mettler FP80 HT Central Processor and FP85 TA Cell and TGA (851/SF/1100). Solubility \u2013 Saturated aqueous solutions of the three different physical forms of indomethacin were left to equilibrate at 25\ub0 for 72 h. Determination of the solubility was carried out spectrophotometrically. RESULTS AND DISCUSSION An important step in the production of the nanoparticles with the pseudo-emulsion technique is their recovery from the reaction vessel, due to difficulties of filtration as well as evaporation of the solvent that leaves into the particle mass surfactants and inorganic salts used for the nanoparticles preparation. Ultracentrifugation demonstrated suitable to eliminate the solvent, followed by a leaching with water to dissolve foreign substances used for the preparation Thermal analysis revealed that indomethacin, in the gamma form as starting material: following the treatment of pseudo-emulsion, undergoes to a polymorph transition. The drug transforms first into the alpha form and then progressively into an amorphous form: these changes are documented by the position of the melting endotherm peaks in DSC thermogram. In the amorphous form the area surface of the peak dramatically decrea..

    Thermal analysis of systems containing theophylline and three types of Compritol

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    The use of fluid-bed or spray-drying processing in the development and production of solid dosage forms is increasing. These processes are traditionally used for granulation and the drying and coating of powders, granules, tablets, beads. Generally speaking, the coating material is dissolved in a solvent (water or organic) prior to spraying. During and after coating the solvent must be evaporated. The use of solvents nowadays is under constraint due to the problems of trace levels, while recovering a solvent often proves expensive. Moreover also long evaporation time of the solvent (especially water) could be a problem. In order to avoid such problems and to reduce costs, it is appealing to use meltable materials, such as waxes or derivatives or other different low-melting lipid materials – as coating agents. The aim of the present study was to analyse the ability of different types of Compritol, namely Compritol 888 ATO (glyceryl di-behenate), Compritol E ATO (mixture of mono-, di- e tri-glycerides of behenic acid: mp 67-80°C) and Compritol HD5 ATO (mixture of glyceril di-behenate and PEG -mp. 60-67°C) to sustain the release of theophylline, used as tracer model drugs incorporated into a solid dispersion prepared by the melting method using the three lipid materials. Formulations with drug:Compritol 10, 20 and 30 % w/w were evaluated: physical mixtures were heat treated at 80°C for 10 min to prepare the solid dispersions. The material thus obtained was maintained at -20° for 2 days and then milled and sieved. Samples of each formulation were analyzed by DSC and HSM, revealing the different solvent ability of the molten phase of each Compritol. In fact at HSM, after the melting of the carrier, undissolved theophylline particles are clearly evident at all the compositions examined that demonstrated to dissolve into the molten carrier at increasing temperature. This event was not documented by DSC thermograms that therefore did not offer important information. HSM technique revealed also suitable to examine the effects of aging. After 6 months comparison of similar situations (composition, temperature, and nature of the carrier) revealed the presence of a larger amount of crystallized material. Increased particle amount was due to crystallization of previously dissolved drug, during the preparation of the solid dispersion that, in the presence of the solid carrier was only delayed. This fact was also confirmed by dissolution profiles: a control of the release was obtained only at the lowest concentration, while at higher concentrations no difference could be observed with respect to pure theophylline: this was hypothesized as due to better coating of the drug particles by the lipid carrier, suggesting at the same time that the concentration range, useful to obtain a control of the release of theophylline, is quite restricted. Better results, in terms of control of the release, were obtained if the molten phase was spray-congealed using an ultrasound assisted device. In this case the process allowed obtaining spherically shaped microparticles: SEM and HSM observation indicated that single theophylline particles were coated by the lipid material that could slow down dissolution of the drug with respect to pure drug. On the contrary in the final dispersion, after solidification, the milling could have acted along fracture lines that made free the drug particle surface, hindering any control to the release by the lipid material

    Preparation of gastroresistant mesalazine lipidic microcapsules

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    INTRODUCTION AND OBJECTIVES Mesalazine or 5-aminosalicylic (5-ASA), a typical antiinflatmmatory drug, is customarily used to maintain remission in inflammatory bowel disease (Carter, 2004). Mesalazine acts topically on the colonic mucosa: current 5-ASA delivery systems have been developed to avoid absorption of mesalazine in the small intestine, thereby delivering maximal amounts of the drug to colonic mucosa (Van den Mooter 2006). The aim of this work was to develop and characterize gastro-resistant multiparticulate system for mesalazine colon delivery in paediatric administration. MATERIAL AND METHODS Mesalazine was kindly supplied by Doppel (Cortemaggiore, Italy) and stearic acid was purchased by ACEF (Fiorenzuola, Italy). Carnauba wax (Produits Roche S.A. France) and Eudragit (Rhom Pharma, Germany) were also used. All other chemicals were of analytical grade. The 5-ASA microcapsules were manufactured in two steps through the spray-congealing technique. In the first step the mesalazine was disperded in a solution of Eudragit L in isopropyl alcohol prepared under stirring at the tempetature of 70\ub0C. The carnauba wax was added to the dispersion and the temperature was raised up until 95\ub0C to evaporate the isopropyl alcohol and io melt the lipid. The melted mass was sprayed through the WPN nozzle at 3.0 bar. In the second step the microcapsules were obtained by disperding the 5-ASA cores in a low melting point lipid as stearic acid at the temperature around 70\ub0C. At this temperature the microsphere did not melt and remained well dispersed in the liquid mass. The dispersion was sprayed with the WPN nozzle at 1.2 bar and the microcapsules were obtained. The drug loading was determined by adding the samples to a simulated intestinal fluid (SIF) at pH 7.4 and heating up to 70\ub0C or to 850C to melt the lipophilic carrier as stearic acid or carnauba wax, respectively. The process was carried out under magnetic stirring for 5 hours to extract completely the 5-ASA. The solution was filtered with microcellulose filter and then assayed by UV at 330 nm. The analysis was peformed in triplicate. The lipid microcapsules were examined both under an optical stereomicroscope (Citoval 2. Jena, Germany) connected to a video camera (JVC, Tokyo, Japan) and Scanning Electron Microscopy (SEM, JSM 6400, Jeol Ltd. Tokyo, Japan). Physical changes in microcapsules during heating were monitored by Hot Stage Microscopy (HSM). A hot plate (FP 52 Mettler, Grefensee, Switzerland) connected to a temperature controller (FP 5 Mettler) was used ..........
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