In the search for appropriate host matrices for highly luminescent molecular guest species, an organo-silica monolithic xerogel prepared by the hydrolysis and co-condensation reactions of ...3-glycidoxypropyltrimethoxysilane (GPTS) and tetraethylorthosilicate (TEOS) is proposed. Such alkoxides allowed the development of hybrid silica monoliths with a cross-linked three-dimensional structure, in which the silica domains are strictly interconnected with the polymeric network. Highly luminescent monoliths were prepared from the immobilization of a blue-green emissive Ir(III) phosphor in the host matrix, with improved luminescent properties attributed to the greater rigidity of the medium and less diffusion of oxygen within the matrix. The structure of the hybrid material was elucidated by high-resolution solid-state NMR, confirming that the final structure of the developed silica matrix is very similar for both Ir(III)-doped and undoped xerogels. Altogether, the experimental strategy used in this work stands as an advance in the design of photo-functional materials with substantial potential for optical and photonic applications.
Highlights
Highly luminescent GPTS:TEOS-derived organosilicate monolithic xerogel is presented.
Structural description of the matrix using high-resolution solid-state NMR techniques.
Improved luminescent properties due to the rigid media and lower diffusion of O
2
.
Versatile hybrid host system promising for optical and luminescent applications.
Calcium phosphate bioactive glasses (BG) and some ceramics are candidates for implantation due to their excellent bonding to bone. Silver is a bactericidal element and can be easily introduced in ...glasses and ceramics. In this work, nanometer-sized bioactive glass particles doped with silver were produced and characterized by Thermal Gravimetric analysis (TG), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD). Water hygroscopy was reduced with increasing silver content. The increase in the amount of silver caused an increase in quartz and metallic silver crystallization while reducing the BG transformation into hydroxyapatite. It was observed the silver reduction leading to metallic silver formation for bioactive glasses containing high amount of silver.
To address the problems associated with the use of unsupported nanomaterials, in general, and molybdenum disulfide (MoS
), in particular, we report the preparation of self-supported hybrid aerogel ...membranes that combine the mechanical stability and excellent textural properties of bacterial nanocellulose (BC)-based organic macro/mesoporous scaffolds with the excellent adsorption-cum-photocatalytic properties and high contaminant removal performance of MoS
nanostructures. A controlled hydrothermal growth and precise tuning of the synthetic parameters allowed us to obtain BC/MoS
-based porous, self-supported, and stable hybrid aerogels with a unique morphology resulting from a molecular precision in the coating of quantum-confined photocatalytic MoS
nanostructures (2-4 nm crystallite size) on BC nanofibrils. These BC/MoS
samples exhibit high surface area (97-137 m
·g
) and pore volume (0.28-0.36 cm
·g
) and controlled interlayer distances (0.62-1.05 nm) in the MoS
nanostructures. Modification of BC with nanostructured MoS
led to an enhanced pollutants removal efficiency of the hybrid aerogels both by adsorptive and photocatalytic mechanisms, as indicated by a detailed study using a specifically designed membrane photoreactor containing the developed photoactive/adsorptive BC/MoS
hybrid membranes. Most importantly, the prepared BC/MoS
aerogel membranes showed high performance in the photoassisted
removal of both organic dye (methylene blue (MB)) molecules (96% removal within 120 min,
= 0.0267 min
) and heavy metal ions (88% Cr(VI) removal within 120 min,
= 0.0012 min
), separately and/or simultaneously, under UV-visible light illumination as well as excellent recyclability and photostability. Samples with interlayer expanded MoS
nanostructures were particularly more efficient in the removal of smaller species (CrO
) as compared to larger (MB) dye molecules. The prepared hybrid aerogel membranes show promising behavior for application in
water purification, representing a significant advancement in the use of self-supported aerogel membranes for photocatalytic applications in liquid media.
Potassium has important physiological functions in eucalypt plantations, increasing their productivity when applied to soil via mineral fertilizers. There is interest in identifying alternative ...sources to KCl owing to its high cost and limited reserves. The aim of the study was to test the effect of replacing KCl with NaCl and phonolite rock powder. Two comparisons were made: (1) application of 283 kg ha
−1
of KCl compared with that of 2125 kg ha
−1
of phonolite rock powder (equivalent to 170 kg ha
−1
of K
2
O in both treatments); (2) application of 139 kg ha
−1
of NaCl compared with that of 183 kg ha
−1
of KCl (equivalent to 2.33 kmol Na and K, respectively). Radial growth, soil water content, leaf water potential (Ψ), accumulated transpiration, stem volume and biomass increment, as well as water use efficiency (WUE) were evaluated. In the first comparison, both fertilizations presented equal values for all characteristics evaluated. In the second, the accumulated transpiration in trees fertilized with KCl was 17% higher than that in plants fertilized with NaCl. In contrast, the WUE was 20% higher in the trees fertilized with NaCl than in those fertilized with KCl, reflecting the lower water consumption for the same increment in stem volume and biomass. We conclude that phonolite rock powder and NaCl are possible substitutes for conventional K fertilization performed with KCl.
Tropical and subtropical plants are generally sensitive to cold and can show appreciable variation in their response to cold stress when exposed to low positive temperatures. Using nylon filter ...arrays, we analyzed the expression profile of 1,536 expressed sequence tags (ESTs) of sugarcane (Saccharum sp. cv SP80-3280) exposed to cold for 3 to 48 h. Thirty-four cold-inducible ESTs were identified, of which 20 were novel cold-responsive genes that had not previously been reported as being cold inducible, including cellulose synthase, ABI3-interacting protein 2, a negative transcription regulator, phosphate transporter, and others, as well as several unknown genes. In addition, 25 ESTs were identified as being down-regulated during cold exposure. Using a database of cold-regulated proteins reported for other plants, we searched for homologs in the sugarcane EST project database (SUCEST), which contains 263,000 ESTs. Thirty-three homologous putative cold-regulated proteins were identified in the SUCEST database. On the basis of the expression profiles of the cold-inducible genes and the data-mining results, we propose a molecular model for the sugarcane response to low temperature.
Educação, Emancipação e Democracia Rodrigues, Fabiana de Cássia; Novaes, Henrique Tahan; Miglioli, Aline Marcondes ...
Revista Fim do Mundo (Online),
06/2022, Letnik:
3, Številka:
7
Journal Article
The use of valve-in-valve transcatheter aortic valve implantation (ViV-TAVI) is increasing, but studies evaluating clinical outcomes in these patients are scarce. Also, there are limited data to ...guide the choice of valve type in ViV-TAVI. Therefore, this CENTER-study evaluated clinical outcomes in patients with ViV-TAVI compared to patients with native valve TAVI (NV-TAVI). In addition, we compared outcomes in patients with ViV-TAVI treated with self-expandable versus balloon-expandable valves. A total of 256 patients with ViV-TAVI and 11333 patients with NV-TAVI were matched 1:2 using propensity score matching, resulting in 256 patients with ViV-TAVI and 512 patients with NV-TAVI. Mean age was 81±7 years, 58% were female, and the Society of Thoracic Surgeons Predicted Risk of Mortality was 6.3% (4.0% to 12.8%). Mortality rates were comparable between ViV-TAVI and NV-TAVI patients at 30 days (4.1% vs 5.9%, p = 0.30) and 1 year (14.2% vs 17.3%, p = 0.34). Stroke rates were also similar at 30 days (2.8% vs 1.8%, p = 0.38) and 1 year (4.9% vs 4.3%, p = 0.74). Permanent pacemakers were less frequently implanted in patients with ViV-TAVI (8.8% vs 15.0%, relative risk 0.59, 95% confidence interval CI 0.37 to 0.92, p = 0.02). Patients with ViV-TAVI were treated with self-expandable valves (n = 162) and balloon-expandable valves (n = 94). Thirty-day major bleeding was less frequent in patients with self-expandable valves (3% vs 13%, odds ratio 5.12, 95% CI 1.42 to 18.52, p = 0.01). Thirty-day mortality was numerically lower in patients with self-expandable valves (3% vs 7%, odds ratio 3.35, 95% CI 0.77 to 14.51, p = 0.11). In conclusion, ViV-TAVI seems a safe and effective treatment for failing bioprosthetic valves with low mortality and stroke rates comparable to NV-TAVI for both valve types.
Polysaccharide based copolymers have been the focus of several research, particularly for the development of drug delivery systems. This study reports on the preparation of nanoparticles from an ...amphiphilic copolymer obtained by the poly(ε-caprolactone) graft in the structure of cashew gum, via ring-opening polymerization. The synthesis of copolymers was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The copolymers exhibit self-organization capability in water, with critical association concentration of 42 and 50 μg mL−1. The nanoparticle hydrodynamic diameters (212 and 202 nm) revealed a decreasing trend with increasing poly(ε-caprolactone) graft percentage. Epirubicin was used as an anticancer drug model and incorporated into the nanoparticles. The encapsulation efficiency reached 50% and 5.0% drug load. Nanoparticles showed an epirubicin controlled release profile, with maximum release of 93.0 ± 4.0% in 72 h, as well as excellent biocompatibility, according to hemolysis and cytotoxicity assays.
•Poly(ε-caprolactone)-graft-cashew gum exhibit self-organization capability.•Nanoparticles showed an epirubicin controlled release profile.•Copolymer shows excellent biocompatibility, according to hemolysis and cytotoxicity assays.
• Age-regulated microRNA156 (miR156) and targets similarly control the competence to flower in diverse species. By contrast, the diterpene hormone gibberellin (GA) and the microRNA319-regulated ...TEOSINTE BRANCHED/CYCLOIDEA/PCF (TCP) transcription factors promote flowering in the facultative long-day Arabidopsis thaliana, but suppress it in the day-neutral tomato (Solanum lycopersicum).
• We combined genetic and molecular studies and described a new interplay between GA and two unrelated miRNA-associated pathways that modulates tomato transition to flowering.
• Tomato PROCERA/DELLA activity is required to promote flowering along with the miR156-targeted SQUAMOSA PROMOTER BINDING–LIKE (SPL/SBP) transcription factors by activating SINGLE FLOWER TRUSS (SFT) in the leaves and the MADS-Box gene APETALA1(AP1)/MC at the shoot apex. Conversely, miR319-targeted LANCEOLATE represses floral transition by increasing GA concentrations and inactivating SFT in the leaves and AP1/MC at the shoot apex. Importantly, the combination of high GA concentrations/responses with the loss of SPL/SPB function impaired canonical meristem maturation and flower initiation in tomato.
• Our results reveal a cooperative regulation of tomato floral induction and flower development, integrating age cues (miR156 module) with GA responses and miR319-controlled pathways. Importantly, this study contributes to elucidate the mechanisms underlying the effects of GA in controlling flowering time in a day-neutral species.
Sugarcane is generally propagated by cuttings of the stalk containing one or more lateral buds, which will develop into a new plant. The transition from the dormant into the active stage constitutes ...a complex phenomenon characterized by changes in accumulation of phytohormones and several other physiological aspects. Abscisic acid (ABA) and methyl-jasmonate (MeJA) are major signaling molecules, which influence plant development and stress responses. These plant regulators modulate gene expression with the participation of many transcriptional factors. Basic leucine zipper proteins (bZIPs) form a large family of transcriptional factors involved in a variety of plant physiological processes, such as development and responses to stress. Query sequences consisting of full-length protein sequence of each of the Arabidopsis bZIP families were utilized to screen the sugarcane EST database (SUCEST) and 86 sugarcane assembled sequences (SAS) coding for bZIPs were identified. cDNA arrays and RNA-gel blots were used to study the expression of these sugarcane bZIP genes during early plantlet development and in response to ABA and MeJA. Six bZIP genes were found to be differentially expressed during development. ABA and MeJA modulated the expression of eight sugarcane bZIP genes. Our findings provide novel insights into the expression of this large protein family of transcriptional factors in sugarcane.
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