Trainer for resection and skills of skin grafting the needle resection

The article presents the results of our own work on the creation of a universal low-budget wear-resistant surgical simulatorВ статье приведены результаты собственной работы по созданию универсального малобюджетного износостойкого хирургического тренажёр

Evidence That Intracellular Stages of Leishmania major Utilize Amino Sugars as a Major Carbon Source

Intracellular parasites, such as Leishmania spp, must acquire suitable carbon sources from the host cell in order to replicate. Here we present evidence that intracellular amastigote stages of Leishmania exploit amino sugars in the phagolysosome of mammalian macrophages as a source of carbon and energy. L. major parasites are capable of using N-acetylglucosamine and glucosamine as primarily carbon sources and contain key enzymes required for conversion of these sugars to fructose-6-phosphate. The last step in this pathway is catalyzed by glucosamine-6-phosphate deaminase (GND), which was targeted to glycosomes via a canonical C-terminal targeting signal when expressed as a GFP fusion protein. Mutant parasites lacking GND were unable to grow in medium containing amino sugars as sole carbohydrate source and rapidly lost viability, concomitant with the hyper-accumulation of hexosamine-phosphates. Expression of native GND, but not a cytosolic form of GND, in Δgnd parasites restored hexosamine-dependent growth, indicating that toxicity is due to depletion of glycosomal pools of ATP. Non-lethal increases in hexosamine phosphate levels in both Δgnd and wild type parasites was associated with a defect in promastigote metacyclogenesis, suggesting that hexosamine phosphate levels may influence parasite differentiation. Promastigote and amastigote stages of the Δgnd mutant were unable to replicate within macrophages and were either completely cleared or exhibited reduced lesion development in highly susceptible Balb/c mice. Our results suggest that hexosamines are a major class of sugars in the macrophage phagolysosome and that catabolism of scavenged amino sugars is required to sustain essential metabolic pathways and prevent hexosamine toxicity

Plasmodial sugar transporters as anti-malarial drug targets and comparisons with other protozoa

Glucose is the primary source of energy and a key substrate for most cells. Inhibition of cellular glucose uptake (the first step in its utilization) has, therefore, received attention as a potential therapeutic strategy to treat various unrelated diseases including malaria and cancers. For malaria, blood forms of parasites rely almost entirely on glycolysis for energy production and, without energy stores, they are dependent on the constant uptake of glucose. Plasmodium falciparum is the most dangerous human malarial parasite and its hexose transporter has been identified as being the major glucose transporter. In this review, recent progress regarding the validation and development of the P. falciparum hexose transporter as a drug target is described, highlighting the importance of robust target validation through both chemical and genetic methods. Therapeutic targeting potential of hexose transporters of other protozoan pathogens is also reviewed and discussed

Monitoring biological wastewater treatment processes: Recent advances in spectroscopy applications

Biological processes based on aerobic and anaerobic technologies have been continuously developed to wastewater treatment and are currently routinely employed to reduce the contaminants discharge levels in the environment. However, most methodologies commonly applied for monitoring key parameters are labor intensive, time-consuming and just provide a snapshot of the process. Thus, spectroscopy applications in biological processes are, nowadays, considered a rapid and effective alternative technology for real-time monitoring though still lacking implementation in full-scale plants. In this review, the application of spectroscopic techniques to aerobic and anaerobic systems is addressed focusing on UV--Vis, infrared, and fluorescence spectroscopy. Furthermore, chemometric techniques, valuable tools to extract the relevant data, are also referred. To that effect, a detailed analysis is performed for aerobic and anaerobic systems to summarize the findings that have been obtained since 2000. Future prospects for the application of spectroscopic techniques in biological wastewater treatment processes are further discussed.The authors thank the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors also acknowledge the financial support to Daniela P. Mesquita and Cristina Quintelas through the postdoctoral Grants (SFRH/BPD/82558/2011 and SFRH/BPD/101338/2014) provided by FCT - Portugal.info:eu-repo/semantics/publishedVersio

Sedimentation behaviour study by three optical methods — granulometric and electrophoresis measurements, dispersion optical analyser

International audienceTaking into account the importance of characterisation of stability of dispersed systems in both fundamental research and industrial technology, three optical techniques, were used and compared to study sedimentation behaviours of mineral suspensions.The agglomeration and dispersion phenomena of mineral suspensions in water and ethanol media, has been studied by a granulometric and sedimentation approach (electrophoresis mobility, particle size distribution, clarifying speed, sediment formation).So, this experimental work has perfectly shown the necessity to achieve a complementary approach by these three optical methods to completely investigate the sedimentation behaviours

Flowability of a mixture of two powders obtained by co-grinding, mixing and surface treatment

International audienceUsage properties of powder mixtures like flowability and floodability depend strongly on their granular characteristics: size, shape, surface and spread of particle size. The products used are mixtures elaborated from two micron sized powders, made of synthetic minerals. Their particle size distributions are each initially mono-modal, respectively 5 mm and 70 mm. The mixture elaboration procedure consists in making several successive combined stages of co-grinding, mixing and surface treatment by addition of surfactants. We obtain thus several mixtures M having different rheological behaviours and particle size distributions-ascertained on a electron i beam microscope. The results permitted in understanding the influence of the granular macrostructure and the effect of a surface treatment on a powder's rheological behaviour

Synergistic effect between hydrophobic oxide nanoparticles and ammonium polyphosphate on fire properties of poly(methyl methacrylate) and polystyrene

International audienceSynergism on fire properties has been investigated between nano-sized hydrophobic oxides (alumina and silica) and ammonium polyphosphate (AP) flame-retardant additive. Thermal degradation of mixed additives (50% w/w) showed the impact of oxides on AP degradation. The effect of modified nanoparticles was compared with corresponding hydrophilic oxide as regards thermal and fire behaviour. The nanocomposites prepared by melt-blending were evaluated by thermogravimetric analysis and cone calorimetry measurements. Residues were characterized by ATR-FTIR spectroscopy, X-ray diffraction and SEM-EDX experiments. A noteworthy decrease of peak of heat release rate and smoke opacity as well as an increase of LOI were noticed with hydrophobic silica combined with AP both in PMMA and PS. This flame-retardant behaviour was ascribed mainly to the formation of a specific silicon metaphosphate (SiP2O7) crystalline phase which contributes to promote charring and an efficient insulating layer

Impact of modified alumina oxides on the fire properties of PMMA and PS nanocomposites

International audienc