Les auteurs présentent un nouveau type de convertisseur continu-continu à étage intermédiaire utilisant les propriétés des circuits résonnants. Une étude analytique des convertisseurs à résonance permet de décrire le fonctionnement statique et d'évaluer les caractéristiques de ces convertisseurs. La modélisation a été effectuée et met en relief le comportement dynamique de ces convertisseurs. Cette étude en petits signaux a conduit à une représentation sous forme de fonctions de transfert faisant intervenir les variables de sorties (tension) et de contrôle (fréquence de découpage). L'expérimentation de tels convertisseurs a confirmé l'étude analytique et la validité des relations dynamiques
Standard parenteral nutrition solutions are mixtures comprising interacting components that may degrade themselves over time. The objective of this study was to investigate the physicochemical and microbiological stability of a hospital preparation for parenteral nutrition in neonatology. The analyses were performed throughout the storage of the preparations at 2–8 °C (up to 4 months). The extent of stability was based on the determination of amino acids dosage, visual and physicochemical properties (glucose and electrolytes concentrations, pH and osmolality measurements, particle counting) and microbiological analysis (sterility test). A thermal degradation of ascorbic acid was conducted to evaluate the antioxidant properties of the parenteral mixture. Physicochemical and microbiological controls were found to comply with the specifications. Amino acids showed a good stability throughout the 4months storage except for cysteine, which was progressively degraded to cystine, conferring a yellow coloration to parenteral solutions. Parenteral nutrition standards solutions remain stable for 4 months at 2–8 °C, ensuring safe administration in preterm infants.
UITTREKSEL Suid-Afrikaanse leerders se ontoereikende wiskundeprestasie is 'n bron van kommer vir elkeen wat betrokke is by leerfasilitering in wiskunde. Belanghebbendes soek ernstig na moontlike wyses waarop leerders se insig rakende en prestasie in wiskunde verbeter An important conclusion is that although the Harmony South African Mathematics Olympiad accomplishes its goal, it still does not reach as many learners and educators as one would hope. The ideals of the Harmony South African Mathematics Olympiad will probably only be realised if all schools are provided with proper facilities and if the standard of mathematics education is simultaneously improved on a national level. It is therefore vital that all interested parties discuss and reassess this matter promptly and incisively. AGTERGRONDDaar bestaan in 'n redelike mate konsensus dat wiskundeolimpiades 'n uitnemende meganisme is, nie slegs om talentvolle leerders te identifiseer nie, maar ook om leerders betrokke te maak by wiskunde-olimpiades enersyds en wiskunde en wiskundige studierigtings in die algemeen.1 Tewens, Alexander 1 voer aan dat wiskunde-olimpiades oor die beste baanrekord beskik wat metodes betref om begaafde wiskundeleerders te identifiseer. Teen die verwysingsraamwerk wat in die volgende aantal paragrawe aangebied word, maak dit dus sin om bestek te neem van enkele fasette van die Harmony Suid-Afrikaanse Wiskunde-Olimpiade, om enkele tendense uit te lig en om te herbesin oor moontlike maniere waarop hierdie olimpiade verder kan bydra tot die ontwikkeling van wiskundetalent by leerders en -vaardighede by alle leerders en opvoeders in SuidAfrika. Nieteenstaande die feit dat opvoeding en opleiding in postapartheid-Suid-Afrika getransformeer word, manifesteer 'n onaanvaarbare hoë druipsyfer steeds in wiskunde op skool. 2, 3Die tendens is ook sigbaar in tersiêre opleiding: Slegs 20% van alle Suid-Afrikaanse tersiêre studente voltooi hul studies, met studente in die wetenskaplike en handelswetenskaplike velde wat blyke gee van die hoogste druipsyfers. 4In Suid-Afrika is daar verder 'n groot gaping tussen die kwaliteit van onderwys en die prestasies van wit en swart a studente in wiskunde. 5,6 Aangesien graad 12-resultate steeds grootliks bepaal of 'n leerder aanvaar word vir gesogte studie-1 Persoon aan wie korrespondensie gerig moet word. Die outeurs spreek hiermee hul waardering uit teenoor dr. H. de Roos vir sy hulp met die statistiese verwerking van die data. Die outeurs bedank ook Harmony Gold Mining, asook al die leerders en opvoeders wat aan die studie deelgeneem het.
BackgroundSince the March 2015 directive publication of the country’s health department, parenteral nutrition (PN) must be produced by hospital pharmacists, under pharmaceutical responsibility. How to manage closing periods of the hospital pharmacy unit (HPU) to manufacture individualised formulation of paediatric PN (IFPN) for newborns.PurposeSummarise the state of management of HPU closure for IFPN through a survey of hospitals in the country in 2017.Material and methodsA survey with oriented questions according to answers was developed. This form was sent by email to the hospital pharmacist.After general questions (Healthcare Establishment (HE) type: General Hospital Centre (GHC) or University Hospital Centre (UHC), maternity level (classed 1 to 3 in our country)), the first part approaches alternative solutions in case of no production during the HPU closing period. Then, the second part, for IFPN production, which answers different questions concerning formulation validation, production and controls.ResultsNineteen received responses were studied. For HE type: 17 UHC (89.5%) and two GHC (10.5%), all had a maternity (whose 95% with neonatal intensive care unit, level 3 (n=18)). Twelve of 17 pharmacists (65%) report no IFPN during the closing period. A major alternative solution is IFPN, which wereproduced before the closure period (e.g. on Friday). While 16% (n=2) of HE reported using only IFPN, 83.3% (n=10) use IFPN and standardised PN (SPN) and 25% (n=3) associated IFPN, SPN, and industrial PN (with or without supplementation).For other HE (35%, n=7) with PN activity on the weekend, 57.1% (n=4) produces IFPN at HPU and 42.9% (n=3) in the paediatric care unit. Only IFPN which were produced at HPU are formulations checked by a pharmacist. Then, for controls, everybody declared a double visual control during production, 71% realised analytics assays (mainly Na and K), 40% performed microbiologic assay and 60% (n=4) labelling check and mirage. Pharmaceutical liberation is reported on 80%.ConclusionThese results based on statements remain to be analysed cautiously but the trend is no production of IFPN on the weekend. In case of preparations, controls on final product allows the provision of a quality product for newborns. Compliance with the directive remains difficult, perhaps a consensus around SPN with paediatric physicians will make it possible to avoid PN production activity outside the opening period of HPU.References and/or AcknowledgementsPharmacists who had completed survey.No conflict of interest
BackgroundComparison of two recommended European Pharmacopoeia 9th Ed methods of sterility assay (membrane filtration versus direct seeding (DS)) highlights an important difference of sensitivity threshold. This threshold by membrane filtration method is at least lower or equal to 0. 14UFC/mL.PurposeThe aim of the study is to determine the sensitivity threshold of the DS method. This method is currently used in our Hospital Pharmacy Unit (HPU) for binary parenteral nutrition (PN) bags.Material and methodsFor this study, four bags of 30 mL, with a representative composition to those produced each day were each sown by a calibrated strain Bioball® 30 UFC (Candida albicans, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa) in order to obtain a concentration of 1UFC/mL. Then, four levels of dilution were carried out from each PN bag: 0.8 UFC/mL, 0.6 UFC/mL, 0.4 UFC/mL, 0.2 UFC/mL. For each level of dilution, 5 × 1 mL of each bag were taken in order to sow five cultures media, sabouraud dextrose agar slope (biomérieux) or Brain-Heart Infusion Broth (BHIB – comic) according to the strain. Culture media BHIB were incubated for 3 days at 37°C, then 11 days at 22°C, while the culture media sabouraud were incubated for 14 days at 22°C.ResultsAfter 14 days of incubation, for each strain tested, there were between 0 and 4 growths according to the dilution’s level. No concentration made it possible to have 100% of positivity, so sensitivity’s threshold is thus higher than 1UFC/mL. Compared to membrane filtration, the detection’s threshold by DS is at least seven times superior.ConclusionEven if this study did not estimate with precision a sensitivity threshold for the DS method, it has highlighted the limits for sterility assay of binary parenteral nutrition bags. So it possible to confirm the superiority of the membrane filtration method. Tests with higher micro-organisms’ concentrations in binary PN bags are planned to establish with precision the minimal detection threshold.No conflict of interest
BackgroundFollowing the obtaining of the Temporary Recommendation for Use (RTU) in 2015, Hospital Pharmacy Unit (HPU) manufactured syringes of Avastin® (bevacizumab) for treatment of age-related macular degeneration (AMD). Financial interest is significant, as cost of Avastin® is definitely lower than current drugs used for the same disease, and whose similar effectiveness has been demonstrated by several bibliographical studies.PurposeThe aim of the study is to determine the economic impact of this manufacturing of syringes by the HPU, from September 2016 to September 2017.Material and methodsAvastin 2.5 mg/0.1 mL syringes manufacturing requires material resources (isolator, syringes, needles, caps, flask of Avastin®100 mg/4 mL) and staff (pharmacy technicians). Cost calculation of annual production made it possible to estimate the benefits obtained using manufacturated syringes by the ophthalmology care unit in our hospital and by other healthcare establishments (HE). A comparison with the estimated cost of using the Lucentis® (ranibizumab) drug, which has Medicinal Market Authorisation (MMA) in this therapeutic indication, was carried out.ResultsThe HPU produced 39 batches yearly, in 1010 syringes, for a total cost of €15 251. Finally, 17.8% of syringes are used by the hospital and are refunded by social security (€100), and 39.8% of syringes are sold at other HE. Total annual gain is €14,648, while use of Lucentis® would allow an annual earning of €8451. Despite the losses (42.4%) due to a short expiry date, manufacturing Avastin® syringes compared with Lucentis® generates a higher gain, nearly €6,197€.ConclusionWith current consumption, this study shows that manufacturing of Avastin® syringes is financially promising in the treatment of AMD for our HPU, compared to the use of Lucentis®. Nevertheless, to optimise the profitability of Avastin syringes’ production, it would be interesting to correlate sessions’ productions with requests, thus improving production scheduling to decrease losses and increase earnings.No conflict of interest
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