365 research outputs found
Rapid structural characterization of human antibody-antigen complexes through experimentally validated computational docking.
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Opening Study on the Development of a New Biosensor for Metal Toxicity Based on Pseudomonas fluorescens Pyoverdine
No full textTo date, different kinds of biosensing elements have been used effectively for environmental monitoring. Microbial cells seem to be well-suited for this task: they are cheap, adaptable to variable field conditions and give a measurable response to a broad number of chemicals. Among different pollutants, heavy metals are still a major problem for the environment. A reasonable starting point for the selection of a biorecognition element to develop a biosensor for metals could be that of a microorganism that exhibits good mechanisms to cope with metals. Pseudomonads are characterized by the secretion of siderophores (e.g., pyoverdine), low-molecular weight compounds that chelate Fe3+ during iron starvation. Pyoverdine is easily detected by colorimetric assay, and it is suitable for simple online measurements. In this work, in order to evaluate pyoverdine as a biorecognition element for metal detection, the influence of metal ions (Fe3+, Cu2+, Zn2+), but also of temperature, pH and nutrients, on microbial growth and pyoverdine regulation has been studied in P. fluorescens. Each of these variables has been shown to influence the synthesis of siderophore: for instance, the lower the temperature, the higher the production of pyoverdine. Moreover, the concentration of pyoverdine produced in the presence of metals has been compared with the maximum allowable concentrations indicated in international regulations (e.g., 98/83/EC), and a correlation that could be useful to build a colorimetric biosensor has been observed
Rational engineering of the lccβ T. versicolor laccase for the mediator-less oxidation of large polycyclic aromatic hydrocarbons
No full textLaccases are among the most sought-after biocatalyst for many green applications, from biosensors to pollution remedial, because they simply need oxygen from the air to oxidize and degrade a broad range of substrates. However, natural laccases cannot process large and toxic polycyclic aromatic hydrocarbons (PAHs) except in the presence of small molecules, called mediators, which facilitate the reaction but are inconvenient for practical on-field applications. Here we exploited structure-based protein engineering to generate rationally modified fungal laccases with increased ability to process bulky PAHs even in a mediator-less reaction. Computational simulations were used to estimate the impact of mutations in the enzymatic binding pocket on the ability to bind and oxidize a selected set of organic compounds. The most promising mutants were produced and their activity was evaluated by biochemical assays with phenolic and non-phenolic substrates. Mutant laccases engineered with a larger binding pocket showed enhanced activity (up to ~ 300% at pH 3.0) in a wider range of pH values (3.0–8.0) in comparison to the wild type enzyme. In contrast to the natural laccase, these mutants efficiently degraded bulky and harmful triphenylmethane dyes such as Ethyl Green (up to 91.64% after 24 h), even in the absence of mediators, with positive implications for the use of such modified laccases in many green chemistry processes (e.g. wastewater treatment)
Cost-effectiveness analysis in multivessel percutaneous coronary interventions: comparison of drug-eluting stents, bare-metal stents and a mixed approach in patients at high and low risk of target vessel revascularization.
No full textRelations between a Country and a Continent: China and Africa. A first and not a simple matter......
No full textThrough this contribution of a geopolitical approach, the author intends to propose an updated and accurate framework on the relations between China and Africa as well as some critical reflections on various geopolitical and geo-economic aspects concerning the intense development of the diversified economic relations between China and the different African States. China's foreign economic policy in Africa has laid solid foundations through the implementation of the various Sino-African Cooperation Forums that have taken place since 2000 and that have seen an increasing involvement of the Chinese government in the process. This paper intends to make a brief reflection on China's visible economic and geopolitical interest in the African Continent as a whole. The analysis that follows traces the main stages in the history of relations between China and Africa, emphasizing the increased importance of the Sino-African forums that led to what is now known as Chinese neo-colonization. In addition, the case studies of the Silk Road and the Rare Lands are highlighted. Finally, some of the social impacts of the Chinese presence in Africa are also examined such as the construction of new cities for the Chinese migrant population and the teaching of the Chinese language (Mandarin) in schools in some African Countries
Life Sciences in the Ticino: Two Scientists – Two Stories
No full textLuca Varani, PhD, a group leader in Structural Biology at the Institute for Research in Biomedicine, Bellinzona, and Marco Brini, founder and CEO of EnvEve SA, in the Tecnopolo in Manno, describe their life sciences background, their careers and why they percieve their ideal situation
being a basic scientist who wants to remain in science, or being an entrepreneur respectively
Impero, “razza” e politiche della memoria nel documentario contemporaneo italiano. Una prospettiva postcoloniale
No full textAnalisi filmica in chiave postcoloniale di sei documentari italiani sulla memoria del colonialismo italiano: Pays Barbare (Yervant Gianikian e Angela Ricci Lucchi, 2013), Oltremare (Loredana Bianconi, 2017), Inconscio italiano (Luca Guadagnino, 2011), Pagine nascoste (Sabrina Varani, 2018), If Only I Were That Warrior (Valerio Ciriaci, 2015), Asmarina (Alan Maglio e Medhin Paolos, 2015)
Effects of Immunologic Rejection in Eyes Following Selective Lamellar Keratoplasty
No full textIl rigetto immunitario dell'allotrapianto è ancora una delle principali cause di fallimento dell'innesto. La gestione e la probabilità di reversibilità del rigetto immunitario dell'allotrapianto sono in gran parte determinate dallo strato corneale interessato. Metodi Questa serie di casi interventistici monocentrici include occhi sottoposti a cheratoplastica lamellare selettiva. Prima dell'intervento, tutti i pazienti vengono sottoposti a un esame oftalmologico completo. Ogni paziente è stato programmato per un esame oftalmologico completo ogni anno dopo l'intervento. Ogni evento avverso, inclusi rigetto e fallimento, è stato registrato. L'ECD postoperatoria in tutti i casi e l'ECD basale per i casi di ALK sono stati ottenuti tramite microscopia speculare senza contatto. Verrà eseguita un'analisi statistica tra i valori BSCVA ed ECD preoperatori e postoperatori utilizzando l'analisi della varianza. Un valore p inferiore a 0,05 sarà considerato statisticamente significativo.
Risultati
Abbiamo incluso 3669 occhi sottoposti a cheratoplastica lamellare selettiva per varie indicazioni. Abbiamo osservato 33 (4,52%) casi di rigetto immunologico stromale nel gruppo DALK, abbiamo anche osservato 89 (3,99%) rigetto immunologico endoteliale nel gruppo DSAEK. Infine, abbiamo osservato 7 (1,51%) rigetto immunologico endoteliale nel gruppo DMEK. Nel primo gruppo di pazienti sottoposti a DALK, l'ECD medio era 2110,4± 408 cellule/mm2 prima di un episodio di rigetto, 1893± 372 cellule/mm2 dopo un episodio di rigetto e 1904± 376 cellule/mm2 all'ultimo follow-up. Nel gruppo DSAEK, l'ECD medio era di 1668±455 cellule/mm2 prima di un episodio di rigetto e 1079 ± 611 cellule/mm2 dopo un episodio di rigetto. All'ultimo follow-up, l'ECD era di 726±595 cellule/mm2. Nel gruppo DMEK, l'ECD medio prima del rigetto era di 2030± 469 cellule/mm2, l'ECD medio dopo il rigetto era di 1168 ± 617 mentre all'ultimo follow-up, l'ECD medio era di 1014 ± 250 cellule/mm2. Per confrontare gli effetti del rigetto stromale immunologico sulle cellule autologhe endoteliali in occhi sottoposti a DALK, abbiamo arruolato un gruppo di controllo di 65 occhi DALK che erano esenti da rigetto durante il periodo di follow-up. Nel gruppo di controllo DALK, l'ECD medio era 2213,7± 364,6 cellule/mm2 al “tempo prima del rigetto”, 2102,8± 351 cellule/mm2 al “tempo dopo un rigetto” e 2108,5± 347,9 cellule/mm2 al
tempo dell'ultimo follow-up. L'ECC era significativamente inferiore nel gruppo di rigetto dopo l'episodio di rigetto immunologico e all'ultimo follow-up con rispettivi valori di P pari a 0,008 e 0,03.
Conclusione
Il rigetto endoteliale è meno comune dopo DMEK che DSAEK. Tuttavia, in entrambi i casi è stata osservata una
significativa riduzione della densità endoteliale. Il rigetto immunologico ha conferito
un rischio aumentato di fallimento dell'innesto.
Inaspettatamente, il rigetto stromale dopo DALK ha un impatto negativo sull'ECC, esponendo il
paziente al rischio di scompenso endoteliale con una significativa riduzione dell'acuità visiva
e della qualità della vita.Immune allograft rejection is still one of the main causes of graft failure. The management and likelihood of reversibility of immune allograft rejection is largely determined by the corneal layer affected.
Methods
This single center interventional case series includes eyes that underwent selective lamellar keratoplasty . Before surgery, all patients undergo a complete ophthalmologic examination, Each patient has been scheduled for a complete ophthalmological examination annually after surgery Every adverse event, including rejection and failure, was recorded. Postoperative ECD in all cases and baseline ECD for ALK cases were obtained by noncontact specular microscopy. Statistical analysis will be performed between preoperative and postoperative BSCVA and ECD values using analysis of variance. A p value less than 0.05 will be considered statistically significant.
Results
We have included 3669 eyes that underwent selective lamellar keratoplasty for various indications. We observed 33 (4.52%) case of stromal immunological rejection in DALK group, We also observed 89 (3.99%) endothelial immunological rejection in DSAEK group. Finally, we observed 7 (1.51%) endothelial immunological rejection in the DMEK group. In the first group of patients that underwent DALK, mean ECD was 2110.4± 408 cells/mm2 before a rejection episode, 1893± 372 cells/mm 2 after a rejection episode and 1904± 376 cells/mm 2 at last followup.
In the DSAEK group, the mean ECD was 1668±455 cells/mm 2 before a rejection episode and 1079 ± 611 cells/mm 2 after a rejection episode. At the last followup, ECD was 726±595 cells/mm2. In the DMEK group, the mean ECD prerejection was 2030± 469 cells/mm2 , the mean postrejection ECD was 1168 ± 617 while at last followup, mean ECD was 1014 ± 250 cells/mm 2 . In order to compare the effects of immunological stromal rejection on endothelial autologous cells in eyes that underwent DALK we enrolled a control group of 65 DALK eyes that were free from rejection during the follow up period.
In the DALK control group, mean ECD was 2213.7± 364.6 cells/mm 2 at “before rejection time”, 2102.8± 351 cells/mm 2 at “time after a rejection” and 2108.5± 347.9 cells/mm 2 at time last followup. The ECC was significant lower in rejection group after the immunological rejection episode and at the last follow up with respective Pvalue of 0.008 and 0.03.
Conclusion
Endothelial rejection is less common after DMEK than DSAEK. However, in both cases a significant reduction in endothelial density was observed. Immunologic rejection conferred an increased risk of graft failure. Unexpectedly stromal rejection following DALK has negative impact on ECC exposing the patient to risk of endothelial decompensation with a significant reduction in visual acuity and quality of life
L'esame del testimone: intervista cognitiva a confronto con diverse forme di interrogatorio
No full textModifications of low density lipoprotein induced by the interaction with human plasma glycosaminoglycan-protein complexes
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