Search

This work describes the use of the breath figure (BF) method for the fabrication of photoactive porous polymer films and the characterization of their responsive to photo stimulus. The films incorporate self-assembled photoactive polymers and ZnS nanoparticles (NPs). The effect of both components on the optical and morphological properties of the films were analyzed. Films with a hexagonally ordered pattern were obtained. The photoactive polymer was prepared by grafting the photochromic component 1-(2-hydroxyethyl)-3,3-dimethylindoline-6-nitrobenzopyran (SP) to polystyrene-block-polymethacrylic acid (PS-b-PMMA). ZnS NPs were incorporated into the polymer solution, and the films were prepared using spin-coating on glass substrates before subjecting them to the BF method. The hollow footprints were obtained before introducing the ZnS NPs in order to maintain the necessary conditions for hexagonal film growth. Accordingly, the SEM micrographs of the films prepared in the presence of ZnS NPs displayed a loss in the pore arrangement as a consequence of the interaction between SP moiety and NPs. The light-emitting properties of films were characterized by blue and violet colors when exposed to UV light under fluorescence. Progress in the field of breath-figure formation and its application, such as exemplified in this work, leads to functional structures with suitable applications in chemistry and materials science. It is expected that such microstructured polymeric films will have interesting applications in photonic and optoelectronic devices.

Background Gamification is a promising field of research that can benefit education. In particular, it can benefit teaching programming to children. Emotional Learning Companions (ELCs) are interactive systems that dialogue with the students as well as provide them with emotional support. Intervention The design of ELCs was extended with gamification to teach programming to Primary Education children. Riddles, levels, badges, and a leader board with trophies among other traditional gamification elements were incorporated into the learning companion, as well as game mechanics, aesthetics and connection with the players (students) to increase their learning, motivation and satisfaction levels. Methods A pre-post test single group experimental research design was followed to test the proposal. In total, 137 students aged between 10 and 12 years used the gamified learning companion during an academic year in Ecuador. Results The results showed a significant increase in students’ learning scores as well as satisfaction and motivation levels above 90%. Conclusion Therefore, the conclusion is that gamifying ELCs to teach programming in Primary Education can improve students’ learning scores, satisfaction, and motivation levels.

In the present work, three hydrogels of poly(2-hydroxyethyl methacrylate-co-itaconic acid), p(HEMA-co-IA), poly(2-hydroxyethyl methacrylate-co-acrylic acid), p(HEMA-co-AA) and poly(2-hydroxyethyl methacrylate-co-(1-vinyl-2-pyrrolidone)), p(HEMA-co-NVP) were prepared by free radical polymerization in aqueous solution (1:1 monomer mole ratio) using ammonium persulfate as initiator and N,N′-methylenebisacrylamide as crosslinking agent at two different amount (0.3 and 0.9 mol%). The obtained hydrogels were characterized by Fourier transform infrared spectroscopy (FT-IR), which allowed to verify the structural composition. Thermal analysis of the hydrogels was carried out by thermogravimetric analysis (TGA). In addition, hydration capacity (U%) was studied at different experimental conditions such as: time, pH, concentrations of interfering salts (KCl, NaCl and LiCl). The results showed a good polymerization yield (95%). FTIR characterization shows the absorption bands of the functional groups of copolymers. TGA exhibited the characteristic thermal stability of this type of hydrogels. The presence of comonomer AI, AA or NVP in copolymer determine the thermal behavior. Hydration experiments revealed a higher U% in copolymer containing more carboxylic acid groups. The maximum U% values in water were 400% and 250% for p(HEMA-co-AI) and p(HEMA-co-AA), respectively. For P(HEMA-co-NVP) a maximum of U% value was only 74% in water. The effect of interferent salts affects the hydration capacity decreasing U% when the concentration of salts increase.

The adulteration of extra virgin olive oils (EVOO) with virgin olive oils (VOO) previously subjected to a soft deodorization process (to eliminate organoleptic defects from these latter lower quality oils), in up to a 1:1 ratio, in order to be subsequently fraudulently distributed as genuine EVOO represent a serious problem of quality assurance for the olive sector still in force today [1]. The downward evolution of the comparative prices between VOO and EVOO, together with the difficulty of detecting the presence of deodorized oils in adulterated mixtures by means of the quality, purity and sensory analyses contemplated in the legislation, has awakened the ghost of this type of fraud among the main olive oil producing countries, with Spain at the head. To serve as a starting point for the development of a reliable methodology for the unequivocal detection of adulterations of EVOO with deodorized VOO, fraudulent mixtures are needed in order to characterize them in the search for differential quality markers. Likewise, generating fraudulent mixtures requires prior obtaining soft deodorized VOO to be used as adulterants. For obvious reasons, this type of oil is not directly available for purchase in the market so, in the present study, a lab-scale pilot plan was set up to carry out deodorization experiments. An experimental design methodology was used to optimize soft deodorization process conditions in the pilot plant throughout a two-stage procedure. In the first stage, optimization was tackled as a linear design problem considering temperature and deodorization time as the main process variables involved. The perceived intensities of the residual negative attributes that still retained the lampante olive oil used as raw material once deodorized under a certain set of operating conditions were evaluated by an expert sensory panel. A two-level full factorial design with two factors was selected for the analyzed sensory defects (vinegary, fusty/muddy sediment, metallic, mould/humidity and rancid). Design resolution provided a mathematical model that allowed to correlate the process variables with the response variable studied, i.e., to predicted the value of the response variable (degree of organoleptic defect removed) as a function of deodorization conditions. Then, in a second stage, the steepest ascent method was applied to establish optimal conditions for VOO deodorization processes. Optimal deodorization conditions were selected as those for which all undesirable organoleptic properties were entirely removed. For each experiment carried out during optimization, a double sensory evaluation was performed: the first one served to determine the percentage of defect removed immediately after deodorization was completed, and the second one to assess oil stability over time.The optimally deodorized lampante oil obtained was subsequently used to generate adulterated blends with both a recently harvested (fresh) EVOO (arbequina) and a two-year-old EVOO (oliberus) in the range 0-50%. All adulterated EVOO samples thus prepared were submitted to the regulatory analyses required: acidity, peroxide value, UV spectrophotometric measurements and organoleptic evaluation [2-3]. A detailed analysis of the values obtained for the various quality and purity parameters assessed in the set of EVOO adulterated with deodorized VOO allowed to verify that these fraudulent oils were able to evade their detection in all the adulteration range studied, although they were not able to preserve their stability over time. The results of this study confirmed the need for developing and validating new analytical methodologies capable of efficiently detecting and quantifying these adulterations in routine controls at any point of the complex food chain in order to avoid the sale and consumption of products of inferior quality to the one declared.

In this study, we report a low cost, fast and unexplored electrochemical synthesis strategy of copper oxide nanoneedles films as well as their morphological and chemical characterization. The nanostructured films were prepared using electrochemical anodization in alkaline electrolyte solutions of ethylene glycol, water and fluoride ions. The film morphology shows nanoneedle-shaped structures, with lengths up to 1–2 μm, meanwhile, high-resolution X-ray photoelectron spectroscopy (HRXPS) and spectroscopy Raman analyses indicate that a mixture of Cu(II) and Cu(I) oxides, or only Cu(I) oxide, is obtained as the percentage of water in the electrolyte solution decreases. A preliminary study was also carried out for the photocatalytic degradation of the methylene blue (MB) dye under irradiation with simulated sunlight in the presence of the nanoneedles obtained, presenting a maximum degradation value of 88% of MB and, thus, demonstrating the potential characteristics of the material investigated in the degradation of organic dyes.

Poly(ethylene glycol) diacrylate (PEGDA) of different molecular weights (Mn = 575 and 700) was used as crosslinking agent for the photopolymerization of 2-hydroxyethyl methacrylate (HEMA) in order to obtain HEMA/PEGDA-based hydrogels. Composites were synthesized in situ employing a new methodology that implies the addition of different quantities of silver nitrate aqueous solution to the monomer mixture with the finality to obtain hydrogels with different silver nanoparticles’ spatial density and distribution. Samples were characterized by thermal, optical, spectroscopic and structural/morphological methods. Thermal studies showed that the increase of PEGDA molecular weight and the AgNO3 concentration in the reaction mixture enhance the glass transition temperature and the thermal stability of the composites. This behavior could be related to the silver coordination with the polymer network. Infrared spectroscopy with Fourier transform and Raman analyses were realized in order to corroborate the sample chemical structure by the identification of specific functional groups. Surface hydrogel morphology was visualized with scanning electron microscopy analysis, detecting a homogeneous micro-porous surface for the samples obtained from high molecular weight PEGDA. Presence of silver nanoparticles was established by X-ray fluorescence spectroscopy and UV/Vis methods. In this last case, the characteristic silver nanoparticle plasmon was observed. Using Transmission Electron Microscopy it was possible to visualize a homogeneous spatial distribution of spherical silver nanoparticles with very narrow diameter distribution that rounds about 14–21 ± 5 nm. In general, the silver nanoparticle presence in the compounds enhances considerably their thermal/morphological characteristics. Keywords: Silver nanoparticles, HEMA/PEGDA hydrogel, Thermal properties, Crosslinking agent

In the present research, nanocomposites based on copper (I) oxide poly(1-vinyl-2—pyrolidone-co-itaconic acid) nanostructures (Cu2O/p(NVP-co-AI)) were synthesized by the electrodeposition method using the copolymer p(NVP-co-AI) as a stabilizing agent in the reduction of Cu+2 to Cu+. The chemical and physical properties of the nanostructures were characterized by techniques such as scanning electron microscopy, infrared (IR) spectroscopy, Raman and ultraviolet-visible spectrophotometry. The obtained nanostructures are mainly a mixture of agglomerated nanospheres with a diameter of approximately 78 to 91 nm, with an alternation of nanolaminar structures, composed of copper (I) oxide species. In the case of the Cu2O/p(NVP-co-AI) nanocomposite, it was observed a decrease in the carbon-oxygen vibration links of the carbonyl groups in IR intensity for the polymer when it was dissolved in the electrolytic solution, which indicates that interactions are produced by the carbonyl groups with the Cu2O species. In addition, bandgap values of 1.80 and 1.63 eV were estimated by the Kubelka–Munk method for Cu2O and Cu2O/p(NVP-co-AI) samples, respectively.

Hallazgos preliminares del ensayo clínico multicéntrico de evaluación de la seguridad de la aspiración supraglótica continua

Electrospun meshes (EM) composed of natural and synthetic polymers with randomly or aligned fibers orientations containing 0.5% or 1% of thermally reduced graphene oxide (TrGO) were prepared by electrospinning (ES), and their hyperthermia properties were evaluated. EM loaded with and without TrGO were irradiated using near infrared radiation (NIR) at 808 nm by varying the distance and electric potential recorded at 30 s. Morphological, spectroscopic, and thermal aspects of EM samples were analyzed by using SEM-EDS, Raman and X-ray photoelectron (XPS) spectroscopies, X-ray diffraction (XRD), and NIR radiation response. We found that the composite EM made of polyvinyl alcohol (PVA), natural rubber (NR), and arabic gum (AG) containing TrGO showed improved hyperthermia properties compared to EM without TrGO, reaching an average temperature range of 42&ndash, 52 &deg, C. We also found that the distribution of TrGO in the EM depends on the orientation of the fibers. These results allow infering that EM loaded with TrGO as a NIR-active thermal inducer could be an excellent candidate for hyperthermia applications in photothermal therapy.

In the present work, we have investigated the effect of the chemical structure, concentration and solvent on the morphological properties of diblock copolymers at a certain percentage of humidity. The block copolymers were prepared using the atom transfer radical polymerization (ATRP) to obtain well-defined amphiphilic block copolymers with controlled molecular weights and molecular weight narrow size distribution. Breath figures (BF) method was used for the formation of porous materials or microspheres under certain experimental conditions, where the role of the water involved is crucial. The self-assembly behavior of these copolymers in presence of water drops was investigated by optical microscopy and scanning electron microscopy (SEM) exhibiting their ability to form spherical micelles under certain experimental conditions. The morphological properties of the films indicated that these diblock copolymers promotes the coexistence of porous and microspheres in the surface of the films.

In the present work, new biocomposite hydrogels were prepared based on the vinyl monomer 2-methacroyloxyethyltrimethyl ammonium chloride (ClAETA) in the presence of nanofibrillated cellulose (CNF) for the removal of the emerging contaminant nafcillin sodium monohydrate (NFX). The hydrogels were synthesized via free radicals, with the amount of CNF varied, and characterized by fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and scanning electron microscope (SEM) techniques. The capacity to absorb water and to remove NFX was determined through batch studies. It was observed that the presence of CNF significantly promotes both properties, with a hydration capacity of 2100% and an NFX adsorption capacity of 45 mg g−1 in P(ClAETA)1-12-2%CNF (pH 6, 0.01 g of adsorbent, initial concentration of NFX 200 mg g−1). The conformational study showed that in the most stable conformation, CNF avoids direct interaction with the NFX molecule. Herein, the main interactions are predominantly dominated by weak interactions such as London dispersion and electrostatic interactions between charged groups. Molecular dynamics simulations distinguish the existence of π-π stacking interactions between aromatic rings from NFX in the polymer + NFX system. Contact interactions were qualitatively and quantitatively characterized by the NCI index and the IGM analysis.

The effect of the particles size of ZnO nanoparticles, synthesized into the microstructure of honeycomb-porous block copolymer films (poly[(2-hydroxyethylmethacrylate)m-block-poly(N-phenylmaleimide)n]) with different lengths, on the thermal, morphological and optical properties of the porous-structured films were investigated. The functional nanoparticles (NPs) were synthesized by wet preparation methods involving the porous copolymer films. The presence of the copolymer allows the coordination of Zn2+ precursor with the hydrophilic part of the self-assembled block copolymers resulting in hierarchically-ordered NP arrays. With this approach, the microphase separation inside of the polymer domains was used for the organization of pre-formed NPs in their cavities. The results indicated that the sub-domains formed by hydrophilic moiety represent an additional advantage for the diffusion and formation of ZnO nanoparticles. Absorption spectra of the ZnO NPs showed an excitation band around 300 nm, indicating a blue-shift with respect to the ZnO bulk material (at 373 nm). The size and the spherical morphology of the prepared ZnO NPs were determined by transmission electron microscopy (TEM). The overall morphology of polymer nanocomposite (ZnO embedded in the block copolymer) was determined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Keywords: ZnO nanoparticles, Honeycomb patterned porous films, Amphiphilic block copolymer, Thermal and optical properties

The molecular chaperone Hsp90, essential in all eukaryotes, plays a multifaceted role in promoting survival, virulence, and drug resistance across diverse pathogenic fungal species. The chaperone is also critically important, however, to the pathogen's human host, preventing the use of known clinical Hsp90 inhibitors in antifungal applications due to concomitant host toxicity issues. With the goal of developing Hsp90 inhibitors with acceptable therapeutic indices for the treatment of invasive fungal infections, we initiated a program to design and synthesize potent inhibitors with selective activity against fungal Hsp90 isoforms over their human counterparts. Building on our previously reported derivatization of resorcylate natural products to produce fungal-selective compounds, we have developed a series of synthetic aminopyrazole-substituted resorcylate amides with broad, potent, and fungal-selective Hsp90 inhibitory activity. Herein we describe the synthesis of this series, as well as biochemical structure-activity relationships driving selectivity for the Hsp90 isoforms expressed by Cryptococcus neoformans and Candida albicans, two pathogenic fungi of major clinical importance.

Leishmania parasites are trypanosomatid protozoans that persist in infected human hosts to cause a spectrum of pathologies, from cutaneous and mucocutaneous manifestations to visceral leishmaniasis caused by Leishmania donovani. The latter is usually fatal if not treated. Persistence of L. major in the mammalian host depends upon maintaining gene-regulatory programs to support essential parasite metabolic functions. These include expression and assembly of mitochondrial L. major cytochrome c oxidase (LmCOX) subunits, important for Leishmania ATP production. Significantly, under mammalian conditions, WT levels of LmCOX subunits require threshold levels of the Leishmania ribosome-associated scaffold protein, LACK. Unexpectedly, we find that although disruption of LACK’s putative ribosome-binding motif does not grossly perturb ribosome association or global protein synthesis, it nonetheless impairs COX subunit expression, mitochondrial function, and virulence. Our data indicate that the quality of LACK’s interaction with Leishmania ribosomes is critical for LmCOX subunit expression and parasite mitochondrial function in the mammalian host. Collectively, these findings validate LACK’s ribosomal interactions as a potential therapeutic target., During their parasitic life cycle, through sandflies and vertebrate hosts, Leishmania parasites confront strikingly different environments, including abrupt changes in pH and temperature, to which they must rapidly adapt. These adaptations include alterations in Leishmania gene expression, metabolism, and morphology, allowing them to thrive as promastigotes in the sandfly and as intracellular amastigotes in the vertebrate host. A critical aspect of Leishmania metabolic adaptation to these changes is maintenance of efficient mitochondrial function in the hostile vertebrate environment. Such functions, including generation of ATP, depend upon the expression of many mitochondrial proteins, including subunits of cytochrome c oxidase (COX). Significantly, under mammalian temperature conditions, expression of Leishmania major COX subunit IV (LmCOX4) and virulence are dependent upon two copies of LACK, a gene that encodes the ribosome-associated scaffold protein, LACK (Leishmania ortholog of RACK1 [receptor for activated C kinase]). Targeted replacement of an endogenous LACK copy with a putative ribosome-binding motif-disrupted variant (LACKR34D35G36→LACKD34D35E36) resulted in thermosensitive parasites that showed diminished LmCOX4 expression, mitochondrial fitness, and replication in macrophages. Surprisingly, despite these phenotypes, LACKD34D35E36 associated with monosomes and polysomes and showed no major impairment of global protein synthesis. Collectively, these data suggest that wild-type (WT) LACK orchestrates robust LmCOX4 expression and mitochondrial fitness to ensure parasite virulence, via optimized functional interactions with the ribosome. IMPORTANCE Leishmania parasites are trypanosomatid protozoans that persist in infected human hosts to cause a spectrum of pathologies, from cutaneous and mucocutaneous manifestations to visceral leishmaniasis caused by Leishmania donovani. The latter is usually fatal if not treated. Persistence of L. major in the mammalian host depends upon maintaining gene-regulatory programs to support essential parasite metabolic functions. These include expression and assembly of mitochondrial L. major cytochrome c oxidase (LmCOX) subunits, important for Leishmania ATP production. Significantly, under mammalian conditions, WT levels of LmCOX subunits require threshold levels of the Leishmania ribosome-associated scaffold protein, LACK. Unexpectedly, we find that although disruption of LACK’s putative ribosome-binding motif does not grossly perturb ribosome association or global protein synthesis, it nonetheless impairs COX subunit expression, mitochondrial function, and virulence. Our data indicate that the quality of LACK’s interaction with Leishmania ribosomes is critical for LmCOX subunit expression and parasite mitochondrial function in the mammalian host. Collectively, these findings validate LACK’s ribosomal interactions as a potential therapeutic target.

The fabrication of porous-structured polymer films with patterned surface structures has recently attracted increased interest within the material science field. In this work, a series of microstructure scale patterned polymer films were obtained via breath figure methods (BF) with hydrophobic surface films based on self-assembled diblock copolymers by atom-transfer radical polymerization (ATRP). The surface characteristics and morphological properties, pore size, roughness, thickness, and wettability of the block copolymer films was studied in response to variation of the hydrophilic co-monomer structures. A significant improvement of the quality and order of the hydrophobic films was observed in response to thermal annealing and a consequent optimization of the assembly process.

Background TNF-like cytokine 1A (TL1A) and its functional receptor, death-domain-receptor-3 (DR3), are multifunctional mediators of effector and regulatory immunity. We aimed to evaluate the functional role and therapeutic potential of TL1A/DR3 signaling in Crohn's disease-like ileitis. Methods Ileitis-prone SAMP1/YitFc (SAMP) and TNF ΔARE/+ mice were rendered deficient for DR3 or TL1A by microsatellite marker-assisted backcrossing. Pathological and immunological characteristics were compared between control and knockout mice, and mucosal immunophenotype was analyzed by Nanostring microarray assay. The therapeutic effect of pharmacological TL1A neutralization was also investigated. Results DR3 deficiency was associated with restoration of a homeostatic mucosal immunostat in SAMP mice through the regulation of several pro- A nd anti-inflammatory genes. This led to suppression of effector immunity, amelioration of ileitis severity, and compromised ability of either unfractionated CD4 + or CD4 + CD45RB hi mucosal lymphocytes to transfer ileitis to severe combined immunodeficient mice recipients. TNF-driven ileitis was also prevented in TNF ΔARE/+ xDR3 -/- mice, in association with decreased expression of the pro-inflammatory cytokines TNF and IFN-γ. In contrast to DR3, TL1A was dispensable for the development of ileitis although it affected the kinetics of inflammation, as TNF ΔARE/+ xTL1A-/-demonstrated delayed onset of inflammation, whereas administration of a neutralizing, anti-TL1A antibody ameliorated early but not late TNF ΔARE/+ ileitis. Conclusion We found a prominent pro-inflammatory role of DR3 in chronic ileitis, which is only partially mediated via interaction with TL1A, raising the possibility for additional DR3 ligands. Death-domain-receptor-3 appears to be a master regulator of mucosal homeostasis and inflammation and may represent a candidate therapeutic target for chronic inflammatory conditions of the bowel. © 2018 Crohn's and Colitis Foundation. Published by Oxford University Press. All rights reserved.

New strategies are needed to counter the escalating threat posed by drug-resistant fungi. The molecular chaperone Hsp90 affords a promising target because it supports survival, virulence and drug-resistance across diverse pathogens. Inhibitors of human Hsp90 under development as anticancer therapeutics, however, exert host toxicities that preclude their use as antifungals. Seeking a route to species-selectivity, we investigate the nucleotide-binding domain (NBD) of Hsp90 from the most common human fungal pathogen, Candida albicans. Here we report structures for this NBD alone, in complex with ADP or in complex with known Hsp90 inhibitors. Encouraged by the conformational flexibility revealed by these structures, we synthesize an inhibitor with >25-fold binding-selectivity for fungal Hsp90 NBD. Comparing co-crystals occupied by this probe vs. anticancer Hsp90 inhibitors revealed major, previously unreported conformational rearrangements. These insights and our probe’s species-selectivity in culture support the feasibility of targeting Hsp90 as a promising antifungal strategy., The chaperone Hsp90 is a potential target for the development of drugs against fungal pathogens. Here the authors determine the structure of the Hsp90 nucleotide-binding domain from Candida albicans, which they use to design an inhibitor and demonstrate its selectivity for the fungal enzyme, both biochemically and in cells.

Female Aedes aegypti mosquitoes are vectors of arboviruses that cause diseases of public health significance. The discovery of new metabolic targets is crucial for improving mosquito control strategies. We recently demonstrated that glucose oxidation supports ammonia detoxification in A. aegypti. Pyruvate kinase (PK, EC 2.7.1.40) catalyzes the last step of the glycolytic pathway. In most organisms, one or more allosteric effectors control PK activity. However, the kinetic properties and structure of PK in mosquitoes have not been previously reported. In this study, two alternatively spliced mRNA variants (AaPK1 and AaPK2) that code for PKs were identified in the A. aegypti genome. The AaPK1 mRNA variant, which encodes a 529 amino acid protein with an estimated molecular weight of ∼57 kDa, was cloned. The protein was expressed in Escherichia coli and purified. The AaPK1 kinetic properties were identified. The recombinant protein was also crystallized and its 3D structure determined. We found that alanine, glutamine, proline, serine and fructose-1-phosphate displayed a classic allosteric activation on AaPK1. Ribulose-5-phosphate acted as an allosteric inhibitor of AaPK1 but its inhibitory effect was reversed by alanine, glutamine, proline and serine. Additionally, the allosteric activation of AaPK1 by amino acids was weakened by fructose-1,6-bisphosphate, whereas the allosteric activation of AaPK1 by alanine and serine was diminished by glucose-6-phosphate. The AaPK1 structure shows the presence of fructose-1,6-bisphosphate in the allosteric site. Together, our results reveal that specific amino acids and phosphorylated sugars tightly regulate conformational dynamics and catalytic changes of AaPK1. The distinctive AaPK1 allosteric properties support a complex role for this enzyme within mosquito metabolism.

&beta, Cyclodextrin (&beta, CD), the less water soluble of the cyclodextrins, has been used as a capping agent in the preparation of semiconductor nanocrystals or quantum dots (QDs). Nevertheless, no reports have been found in the use of the highly water-soluble polymer of this, prepared by the crosslinking of the &beta, CD units with epichlorohydrin in basic medium (&beta, CDP). This polymer, besides to overcome the low solubility of the &beta, CD, increases the inclusion constant of the guest, two parameters that deserve its use as capping agent, instead of the native cyclodextrin. In the present manuscript, we afforded the in-situ aqueous preparation of cadmium telluride (CdTe) QDs capped with &beta, CDP. The polymer influence on the photoluminescent properties of the nanocrystals was analyzed. The &beta, CDP controls the nanocrystals growth during the Oswald ripening stage. Consequently, the CdTe capped &beta, CDP QDs showed lower Stokes-shift values, higher photoluminescent efficiency, and narrower size distribution than for nanocrystals obtained in the absence of polymer. Transmission electron microscopy (TEM) micrographs and energy dispersive X-ray spectroscopy (EDS) analysis revealed the composition and crystallinity of the CdTe QDs. This &beta, CDP capped CdTe QDs is a potential scaffold for the supramolecular modification of QDs surface.

This work is focused on the removal of Cr(VI) ions from aqueous solution using polymer-enhanced ultrafiltration (PEUF) techniques with water-soluble poly(N,N-dimethylaminoethyl methacrylate), PDMAEMA, used as sorbent. The polymer was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization at different reaction times, characterized by size exclusion chromatography (SEC) and proton nuclear magnetic resonance (1H NMR). The sorption of Cr(VI) was studied by PEUF as a function of pH, the polymer:Cr(VI) molar ratio, and the presence of interfering ions. The PEUF-enrichment mode was used to saturate the polymer and further determine the release of Cr(VI) and regeneration of the polymer using sorption-desorption process. The RAFT polymerization showed a yield in the range 46% to 79% (determined by 1H NMR) for polymers with molecular weight (Mn) between 28 and 195 kg mol−1. The polydispersity estimated by SEC was between 1.1 and 1.8. The capacity of PDMAEMA as sorbent of Cr(VI), by the PEUF technique showed an efficient removal of Cr(VI) (100%, 25 mg L−1 in the feed) at pH 4 using polymer:Cr molar ratio of 40:1. The presence of interfering ions does not significantly decrease the retention capacity of PDMAEMA. Finally the results indicated that PDMAEMA can release Cr(VI) and be regenerated.

International audience; Design, synthesis, structure-activity relationship, cytotoxicity studies, in silico drug-likeness, genotoxicity screening, and in vivo studies of new 1-aryl-3-substituted propanol derivatives led to the identification of nine compounds with promising in vitro (55, 56, 61, 64, 66, and 70-73) and in vivo (66 and 72) antimalarial profiles against Plasmodium falciparum and Plasmodium berghei. Compounds 55, 56, 61, 64, 66 and 70-73 exhibited potent antiplasmodial activity against chloroquine-resistant strain FCR-3 (IC50s < 0.28 μM), and compounds 55, 56, 64, 70, 71, and 72 showed potent biological activity in chloroquine-sensitive and multidrug-resistant strains (IC50s < 0.7 μM for 3D7, D6, FCR-3 and C235). All of these compounds share appropriate drug-likeness profiles and adequate selectivity indexes (77 < SI < 184) as well as lack genotoxicity. In vivo efficacy tests in a mouse model showed compounds 66 and 72 to be promising candidates as they exhibited significant parasitemia reductions of 96.4% and 80.4%, respectively. Additional studies such as liver stage and sporogony inhibition, target exploration of heat shock protein 90 of P. falciparum, targeted delivery by immunoliposomes, and enantiomer characterization were performed and strongly reinforce the hypothesis of 1-aryl-3-substituted propanol derivatives as promising antimalarial compounds.

Drug resistant Plasmodium falciparum parasites represent a major obstacle in our efforts to control malaria, a deadly vector borne infectious disease. This situation creates an urgent need to find and validate new drug targets to contain the spread of the disease. Several genes associated with the unfolded protein response (UPR) including Glucose-regulated Protein 78 kDa (GRP78, also known as BiP) have been deemed potential drug targets. We explored the drug target potential of GRP78, a molecular chaperone that is a regulator of the UPR, for the treatment of P. falciparum parasite infection. By screening repurposed chaperone inhibitors that are anticancer agents, we showed that GRP78 inhibition is lethal to drug-sensitive and -resistant P. falciparum parasite strains in vitro. We correlated the antiplasmodial activity of the inhibitors with their ability to bind the malaria chaperone, by characterizing their binding to recombinant parasite GRP78. Furthermore, we determined the crystal structure of the ATP binding domain of P. falciparum GRP78 with ADP and identified structural features unique to the parasite. These data suggest that P. falciparum GRP78 can be a valid drug target and that its structural differences to human GRP78 emphasize potential to generate parasite specific compounds.

Summary Leishmania are kinetoplastid parasites that cause the sandfly-transmitted disease leishmaniasis. To maintain fitness throughout their infectious life cycle, Leishmania must undergo rapid metabolic adaptations to the dramatically distinct environments encountered during transition between sandfly and vertebrate hosts. We performed proteomic and immunoblot analyses of attenuated L. major strains deficient for LACK, the Leishmania ortholog of the mammalian receptor for activated c kinase (RACK1), that is important for parasite thermotolerance and virulence. This approach identified cytochrome c oxidase (LmCOX) subunit IV as a LACK-dependent fitness protein. Consistent with decreased levels of LmCOX subunit IV at mammalian temperature, and in amastigotes, LmCOX activity and mitochondrial function were also impaired in LACK-deficient L. major under these conditions. Importantly, overexpression of LmCOX subunit IV in LACK-deficient L. major restored thermotolerance and macrophage infectivity. Interestingly, overexpression of LmCOX subunit IV enhanced LmCOX subunit VI expression at mammalian temperature. Collectively, our data suggest LACK promotes Leishmania adaptation to the mammalian host environment by sustaining LmCOX subunit IV expression and hence energy metabolism in response to stress stimuli such as heat. These findings extend the repertoire of RACK1 protein utility to include a role in mitochondrial function.

Block copolymers have been recognized as versatile materials to prepare nanoporous polymer films or mem- branes, but their potential has not been completely explored. This study focuses on the formation and characterization of nanoporous polymer films based on poly(styrene)-block-(methylmethacrylate/methacrylic acid); (PS-b-MMA/MAA) were obtained through atom transfer radical polymerization (ATRP), by using two different protocols: annealing and annealing- irradiation; for improving the formation of microporous surface. The composition, crystallinity and structural order of the films were studied by Raman spectroscopy. The film polymer thickness was obtained through very high resolution ellip- sometry (VHRE). Finally, atomic force microcopy (AFM) and scanning electron microscopy (SEM) techniques were used to detect changes in the porous-structure. These results show that the morphological properties of the block copolymer were affected via the modification of two variables, UV-radiation time and annealing. SEM and AFM micrographs showed that the morphology exhibit a porous ordered structure. Contact angle measurement suggests additional interactions between hydrophilic functional groups that influence the film wettability.