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1.
J Environ Sci (China) ; 149: 394-405, 2025 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-39181652

RESUMO

Heterogeneous crystallization is a common occurrence during the formation of solid wastes. It leads to the encapsulation of valuable/hazardous metals within the primary phase, presenting significant challenges for waste treatment and metal recovery. Herein, we proposed a novel method involving the in-situ formation of a competitive substrate during the precipitation of jarosite waste, which is an essential process for removing iron in zinc hydrometallurgy. We observed that the in-situ-formed competitive substrate effectively inhibits the heterogeneous crystallization of jarosite on the surface of anglesite, a lead-rich phase present in the jarosite waste. As a result, the iron content on the anglesite surface decreases from 34.8% to 1.65%. The competitive substrate was identified as schwertmannite, characterized by its loose structure and large surface area. Furthermore, we have elucidated a novel mechanism underlying this inhibition of heterogeneous crystallization, which involves the local supersaturation of jarosite caused by the release of ferric and sulfate ions from the competitive substrate. The local supersaturation promotes the preferential heterogeneous crystallization of jarosite on the competitive substrate. Interestingly, during the formation of jarosite, the competitive substrate gradually vanished through a dissolution-recrystallization process following the Ostwald rule, where a metastable phase slowly transitions to a stable phase. This effectively precluded the introduction of impurities and reduced waste volume. The goal of this study is to provide fresh insights into the mechanism of heterogeneous crystallization control, and to offer practical crystallization strategies conducive to metal separation and recovery from solid waste in industries.


Assuntos
Cristalização , Compostos Férricos , Compostos Férricos/química , Sulfatos/química , Compostos de Ferro/química , Ferro/química , Eliminação de Resíduos/métodos
2.
Heliyon ; 10(16): e35809, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39220980

RESUMO

The limited industrial use of indigenous varieties of native potatoes has caused a decrease in its cultivation, restricting it to the self-consumption of the Andean population. The present study analyzed the physicochemical, thermal, and structural properties of the starches extracted from four of these varieties Aq'hu Pukucho, Yurakk Kkachun Wakkachi, Yurac Anca, and Huarmi Mallco, as a potential source of be used in industries such as food, pharmaceutical and, bioplastics. The percentage yield in wet extraction ranged between 14.53 and 20.26 %. The luminosity L* and whiteness index (WI) values were observed in ranges of 90.75-92.71 and 90.05-91.50, respectively. The Finding revealed various techno-functional properties, since the level of amylose varied between 36.29 and 43.97 %, an average zeta potential of -22 mV, and a maximum viscosity between 19,450-14,583 cP. The starches showed consistent thermal behavior since the TGA curves showed three stages with gelatinization temperatures that ranged between 54.9 and 59.75 °C, an enthalpy of 3.60-6.62 J/g, and various shapes of particles such as circular, elliptical, and oval. In conclusion, the relationships between variables such as water absorption index, swelling power, viscosity, crystallinity, enthalpy, and gelatinization temperature reveal different characteristics of each type of starch, which can influence its use.

3.
Artigo em Inglês | MEDLINE | ID: mdl-39222305

RESUMO

Crystal polymorphism serves as a strategy to study the conformational flexibility of proteins. However, the relationship between protein crystal packing and protein conformation often remains elusive. In this study, two distinct crystal forms of a green fluorescent protein variant, NowGFP, are compared: a previously identified monoclinic form (space group C2) and a newly discovered orthorhombic form (space group P212121). Comparative analysis reveals that both crystal forms exhibit nearly identical linear assemblies of NowGFP molecules interconnected through similar crystal contacts. However, a notable difference lies in the stacking of these assemblies: parallel in the monoclinic form and perpendicular in the orthorhombic form. This distinct mode of stacking leads to different crystal contacts and induces structural alteration in one of the two molecules within the asymmetric unit of the orthorhombic crystal form. This new conformational state captured by orthorhombic crystal packing exhibits two unique features: a conformational shift of the ß-barrel scaffold and a restriction of pH-dependent shifts of the key residue Lys61, which is crucial for the pH-dependent spectral shift of this protein. These findings demonstrate a clear connection between crystal packing and alternative conformational states of proteins, providing insights into how structural variations influence the function of fluorescent proteins.

4.
ACS Appl Mater Interfaces ; 16(36): 46964-46974, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39225124

RESUMO

The use of solar energy for photocatalysis holds great potential for sustainable pollution reduction. Titanium dioxide (TiO2) is a benchmark material, effective under ultraviolet light but limited in visible light utilization, restricting its application in solar-driven photocatalysis. Previous studies have shown that semiconductor heterojunctions and nanostructuring can broaden the TiO2's photocatalytic spectral range. Semiconductor heterojunctions are interfaces formed between two different semiconductor materials that can be engineered. Especially, type II heterojunctions facilitate charge separation, and they can be obtained by combining TiO2 with, for example, iron(III) oxide (Fe2O3). Nanostructuring in the form of 3D inverse opals (IOs) demonstrated increased TiO2 light absorption efficiency of the material, by tailoring light-matter interactions through their photonic crystal structure and specifically their photonic stopband, which can give rise to a slow photon effect. Such effect is hypothesized to enhance the generation of free charges. This work focuses on the above-described effects simultaneously, through the synthesis of TiO2-Fe2O3 IOs via multilayer atomic layer deposition (ALD) and the characterization of their photocatalytic activities. Our results reveal that the complete functionalization of TiO2 IOs with Fe2O3 increases the photocatalytic activity through the slow photon effect and semiconductor heterojunction formation. We systematically explore the influence of Fe2O3 thickness on photocatalytic performance, and a maximum photocatalytic rate constant of 1.38 ± 0.09 h-1 is observed for a 252 nm template TiO2-Fe2O3 bilayer IO consisting of 16 nm TiO2 and 2 nm Fe2O3. Further tailoring the performance by overcoating with additional TiO2 layers enhances photoinduced crystallization and tunes photocatalytic properties. These findings highlight the potential of TiO2-Fe2O3 IOs for efficient water pollutant removal and the importance of precise nanostructuring and heterojunction engineering in advancing photocatalytic technologies.

5.
ACS Appl Mater Interfaces ; 16(36): 48565-48575, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39225113

RESUMO

An essential step toward enabling the production of renewable and cost-efficient fuels is an improved understanding of the performance of energy conversion materials. In recent years, there has been growing interest in ternary metal oxides. Particularly, α-SnWO4 exhibited promising properties for application to photoelectrochemical (PEC) water splitting. However, the number of corresponding studies remains limited, and a deeper understanding of the physical and chemical processes in α-SnWO4 is necessary. To date, charge-carrier generation, separation, and transfer have not been exhaustively studied for SnWO4-based photoelectrodes. All of these processes depend on the phase composition, not only α-SnWO4 but also on the related phases SnW3O9 and WO3, as well as on their spatial distributions resulting from the coating synthesis. In the present work, these processes in different phases of tin tungstate films were investigated by transient surface photovoltage (TSPV) spectroscopy to complement the analysis of the applicability of α-SnWO4 thin films for practical PEC oxygen evolution. Pure α-SnWO4 films exhibit higher photoactivities than those of films containing secondary SnW3O9 and WO3 phases due to the higher recombination of charge carriers when these phases are present.

6.
Food Res Int ; 194: 114871, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39232509

RESUMO

Emulsions stabilized via Pickering particles are becoming more and more popular due to their high stability and biocompatibility. Hence, developing new ways to produce effective Pickering particles is essential. In this work, we present a crystal engineering approach to obtain precise control over particle properties such as size, shape, and crystal structure, which may affect wettability and surface chemistry. A highly reproducible synthesis method via anti-solvent crystallization was developed to produce sub-micron sized curcumin crystals of the metastable form III, to be used as Pickering stabilizers. The produced crystals presented a clear hydrophobic nature, which was demonstrated by their preference to stabilize water-in-oil (W/O) emulsions. A comprehensive experimental and computational characterization of curcumin crystals was performed to rationalize their hydrophobic nature. Analytical techniques including Raman spectroscopy, powder X-ray diffraction (PXRD), Solid-State Nuclear Magnetic Resonance (SSNMR), scanning electron microscopy (SEM), Differential Scanning Calorimetry (DSC), confocal fluorescence microscopy and contact angle measurements were used to characterize curcumin particles in terms of shape, size and interfacial activity. The attachment energy model was instead applied to study relevant surface features of curcumin crystals, such as topology and facet-specific surface chemistry. This work contributes to the understanding of the effect of crystal properties on the mechanism of Pickering stabilization, and paves the way for the formulation of innovative products in fields ranging from pharmaceuticals to food science.


Assuntos
Cristalização , Curcumina , Emulsões , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Curcumina/química , Emulsões/química , Difração de Raios X , Microscopia Eletrônica de Varredura , Análise Espectral Raman , Varredura Diferencial de Calorimetria , Molhabilidade , Propriedades de Superfície , Água/química , Espectroscopia de Ressonância Magnética
7.
Adv Mater ; : e2410255, 2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39223930

RESUMO

Efficient and stable red perovskite light-emitting diodes (PeLEDs) demonstrate promising potential in high-definition displays and biomedical applications. Although significant progress has been made in device performance, meeting commercial demands remains a challenge in the aspects of long-term stability and high external quantum efficiency (EQE). Here, an in situ crystallization regulation strategy is developed for optimizing red perovskite films through ingenious vapor design. Mixed vapor containing dimethyl sulfoxide and carbon disulfide (CS2) is incorporated to conventional annealing, which contributes to thermodynamics dominated perovskite crystallization for well-aligned cascade phase arrangement. Additionally, the perovskite surface defect density is minimized by the CS2 molecule adsorption. Consequently, the target perovskite films exhibit smooth exciton energy transfer, reduced defect density, and blocked ion migration pathways. Leveraging these advantages, spectrally stable red PeLEDs are obtained featuring emission at 668, 656, and 648 nm, which yield record peak EQEs of 30.08%, 32.14%, and 29.04%, along with prolonged half-lifetimes of 47.7, 60.0, and 43.7 h at the initial luminances of 140, 250, and 270 cd m-2, respectively. This work provides a universal strategy for optimizing perovskite crystallization and represents a significant stride toward the commercialization of red PeLEDs.

8.
Adv Mater ; : e2410363, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39225441

RESUMO

The low crystallinity of the perovskite layers and many defects at grain boundaries within the bulk phase and at interfaces are considered huge barriers to the attainment of high performance and stability in perovskite solar cells (PSCs). Herein, a robust photoelectric imidazole-linked porphyrin-based covalent organic framework (PyPor-COF) is introduced to precisely control the perovskite crystallization process and effectively passivate defects at grain boundaries through a sequential deposition method. The 1D porous channels, abundant active sites, and high crystallization orientation of PyPor-COF offer advantages for regulating the crystallization of PbI2 and eliminating defects. Moreover, the intrinsic electronic characteristics of PyPor-COF endow a more closely matched energy level arrangement within the perovskite layer, which promotes charge transport and thereby suppresses the recombination of photogenerated carriers. The champion PSCs containing PyPor-COF achieved power conversion efficiencies of 24.10% (0.09 cm2) and 20.81% (1.0 cm2), respectively. The unpackaged optimized device is able to maintain its initial efficiency of 80.39% even after being exposed to air for 2000 h. The device also exhibits excellent heating stability and light stability. This work gives a new impetus to the development of highly efficient and stable PSCs via employing COFs.

9.
J Colloid Interface Sci ; 678(Pt A): 776-784, 2024 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-39217693

RESUMO

Chemical defects at the surface and grain boundaries of perovskite crystals cause deterioration of conversion efficiency and stability of perovskite solar cells (PSCs). In this study, a multifunctional additive, 5-fluoro-2-pyrimidine carbonitrile (FPDCN) molecule, is added into the perovskite precursor solution in order to passivate the uncoordinated Pb2+ by the cyanogen (-CN) group and pyrimidine N in FPDCN. Interestingly, fluorine (F) atoms interact with FA+ to form hydrogen bonds, which could regulate the perovskite crystallization process for the formation of high-quality perovskite crystals. Besides, the F atoms in FPDCN increase the water contact angle of perovskite films. As a result, the carrier extraction and transport in the perovskite film are significantly enhanced, and the non-radiative recombination is suppressed. The corresponding devices achieve a champion photovoltaic conversion efficiency (PCE) of 20.7 % and a fill factor (FF) of over 83 %. The device based on FPDCN shows long-term stability under a high-humidity atmospheric environment by maintaining 85 % of the initial efficiency after aging of 700 h in the glove box. This study provides a simple and convenient method to prepare stable and efficient PSCs by optimizing the perovskite precursor solution.

10.
Adv Healthc Mater ; : e2402029, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39235719

RESUMO

Biocompatible rod-shaped nanoparticles of controlled length can be produced through the heat-induced "living" seeded crystallization-driven self-assembly (CDSA) of poly(2-isopropyl-2-oxazoline)-containing block copolymers. With a hydrophilic poly(2-methyl-2-oxazine) or poly(2-methyl-2-oxazoline) corona, these nanorods have proven non-cytotoxic, non-hemolytic, and ideal for use as a polymer-based drug delivery system. This study demonstrates a facile, one-pot method for the synthesis of mycophenolic acid (MPA)-conjugated block copolymer "unimers" for use in seeded CDSA. Through altering block order during sequential monomer addition cationic ring-opening polymerization (CROP), MPA is conjugated to either the chain end of the core-forming or corona-forming block. This allows bioactive polymer nanorods to be prepared with MPA positioned at either the periphery of the corona, or at the core-corona interface of the nanorod formed during seeded CDSA. In vitro, these nanorods arrest growth in human T and B lymphocytes, with reduced effect in "off-target" monocytes when compared with unconjugated MPA. Furthermore, the conjugation of MPA to the core-corona interface of the nanorods leads to a slower release and reduced cytostatic effect. This study offers a robust investigation into the effect of steric hindrance and corona chemistry on the therapeutic potential of drug-conjugated CDSA nanorods and demonstrates the potential of poly(2-oxazoline)/poly(2-oxazine)-based CDSA nanomaterials as effective drug delivery platforms.

11.
Int J Biol Macromol ; 279(Pt 2): 135242, 2024 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-39218173

RESUMO

We have recently reported a set of urinary proteins that inhibited calcium oxalate (CaOx) stone development. However, physicochemical properties that determine their inhibitory activities remained unknown. Herein, human urinary proteins were chromatographically fractionated into 15 fractions and subjected to various CaOx crystal assays and identification by nanoLC-ESI-Qq-TOF MS/MS. Their physicochemical properties and crystal inhibitory activities were subjected to Pearson correlation analysis. The data showed that almost all urinary protein fractions had crystal inhibitory activities. Up to 128 proteins were identified from each fraction. Crystallization inhibitory activity correlated with percentages of Ca2+-binding proteins, stable proteins, polar amino acids, alpha helix, beta turn, and random coil, but inversely correlated with number of Ox2--binding motifs/protein and percentage of unstable proteins. Crystal aggregation inhibitory activity correlated with percentage of stable proteins but inversely correlated with percentage of unstable proteins. Crystal adhesion inhibitory activity correlated with percentage of stable proteins and GRAVY, but inversely correlated with pI, instability index and percentages of unstable proteins and positively charged amino acids. However, there was no correlation between crystal growth inhibitory activity and any physicochemical properties. In summary, some physicochemical properties of urinary proteins can determine and may be able to predict their CaOx stone inhibitory activities.

12.
J Pharm Sci ; 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39243976

RESUMO

Hydroxypropyl methyl cellulose acetate succinate (HPMCAS) is one of the polymers of choice in formulating amorphous solid dispersions (ASDs) and helps to sustain high levels of drug supersaturation by delaying drug crystallization. Herein, the impact of HPMCAS chemistry on the solution crystallization kinetics of a fast-crystallizing lipophilic drug, posaconazole (PCZ), from the aqueous bulk phase and the drug-rich phase generated by liquid-liquid phase separation (LLPS), was studied. Three grades of HPMCAS: L, M, and H, which differ in the degree of acetyl and succinoyl substitution (A/S ratio), were compared. The influence of the polymers on the nucleation induction time, and LLPS concentration of PCZ, as well as the size, ζ-potential and composition of the nano-sized drug-rich phase was determined. An increase in the nucleation induction time was observed with an increase in the polymer A/S ratio. A blue shift in the fluorescence emission spectrum of PCZ suggested a greater extent of interaction between PCZ and HPMCAS with an increase in the A/S ratio. More polymer partitioning into the drug-rich phase was also observed with an increase in the A/S ratio, resulting in smaller droplets. A greater extent of ionization of HPMCAS upon increasing the pH from 5.5 to 7.5 decreased the hydrophobicity of the polymer resulting in shorter nucleation induction times. The phase behavior of PCZ in ASD release studies was consistent with these observations, where the shortest duration of supersaturation was observed with the L grade. Although the H grade provided the best inhibition of crystallization, complete release was only observed at higher pH. HPMCAS grade thus influences the kinetics of PCZ crystallization following release from an ASD, as well as the extent of release at physiologically relevant pH conditions. This study provides insights into the role of HPMCAS chemistry and ionization as factors influencing its ability to act as a crystallization inhibitor.

13.
Carbohydr Polym ; 345: 122583, 2024 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-39227111

RESUMO

Herein, the effects of temperature cycling (4 °C/50 °C/100 °C) on the recrystallization, physicochemical properties, and digestibility of debranched starch (DBS) were investigated. Temperature cycling involved heating DBS to 100 °C to dissociate weak heat-sensitive crystalline structures and cooling to 4 °C to induce the rapid growth of crystal nuclei, followed by maintaining the temperature at 50 °C to promote orderly crystalline growth. This procedure aimed to increase the degree of crystalline structure in recrystallized DBS, thereby resulting in DBS that was heat- and digestion-resistant. Temperature cycling increased the dissociation temperature of DBS, and temperatures of up to 114.8 °C were attained after five cycling times. With increasing cycles, the crystalline structure of DBS transitioned from B-type to the more robust and compact A-type, and the crystallinity increased to ∼81.9 % (after seven cycles). Raman and Fourier transform infrared (FTIR) spectra indicated that temperature cycling enhanced the short-range ordered structure of DBS. Moreover, in vitro digestion experiments demonstrated that the resistant starch content of DBS increased to ∼61.9 % after eight cycles. To summarize, this study demonstrated a green and effective method for preparing heat-and digestion-resistant recrystallized DBS, which can be used for developing dietary supplements and low gastrointestinal staples.

14.
Food Res Int ; 192: 114683, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39147537

RESUMO

This work evaluated structured lipids (SLs) through chemical and enzymatic interesterification (CSLs and ESLs). Blends of soybean oil and peanut oil 1:1 wt% were used, with gradual addition of fully hydrogenated crambe to obtain a final behenic acid concentration of 6, 12, 18, and 24 %. Chemical catalysis used sodium methoxide (0.4 wt%) at 100 °C for 30 min, while enzymatic catalysis used Lipozyme TL IM (5 wt%) at 60 °C for 6 h. Major fatty acids identified were C16:0, C18:0, and C22:0. It was observed that with gradual increase of hard fat, the CSLs showed high concentrations of reaction intermediates, indicating further a steric hindrance, unlike ESLs. Increased hard fat also altered crystallization profile and triacylglycerols composition and ESLs showed lower solid fat, unlike CSLs. Both methods effectively produced SLs as an alternative to trans and palm fats, view to potential future applications in food products.


Assuntos
Óleo de Palmeira , Óleo de Soja , Óleo de Palmeira/química , Óleo de Soja/química , Esterificação , Óleo de Amendoim/química , Ácidos Graxos trans/química , Ácidos Graxos trans/análise , Ácidos Graxos/química , Lipídeos/química , Triglicerídeos/química , Manipulação de Alimentos/métodos , Lipase/química , Lipase/metabolismo , Hidrogenação
15.
Angew Chem Int Ed Engl ; : e202410378, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39143026

RESUMO

Various isomers have been developed to regulate the morphology and reduce defects in state-of-the-art perovskite solar cells. To insight the structure-function-effect correlations for the isomerization of thiourea derivatives on the performance of the perovskite solar cells (PSCs), we developed two thiourea derivatives [(3,5-dichlorophenyl)amino]thiourea (AT) and N-(3,5-dichlorophenyl)hydrazinecarbothioamide (HB). Supported by experimental and calculated results, it was found that AT can bind with undercoordinated Pb2+ defect through synergistic interaction between N1 and C=S group with a defect formation energy of 1.818 eV, which is much higher than that from the synergistic interaction between two -NH- groups in HB and perovskite (1.015 eV). Moreover, the stronger interaction between AT and Pb2+ regulates the crystallization process of perovskite film to obtain a high-quality perovskite film with high crystallinity, large grain size, and low defect density. Consequently, the AT-treated FACsPbI3 device engenders an efficiency of 25.71% (certified as 24.66%), which is greatly higher than control (23.74%) and HB-treated FACsPbI3 devices (25.05%). The resultant device exhibits a remarkable stability for maintaining 91.0% and 95.2% of its initial efficiency after aging 2000 h in air condition or tracking at maximum power point for 1000 h, respectively.

16.
Sci Rep ; 14(1): 18554, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39122858

RESUMO

Crystallization occurs as dissolved substances gradually solidify into crystal layers within a liquid, which can increase the capability of fluids to transfer heat. In this study, the growth of crystal layer in nanofluids produced from carbon-based effervescent tablets was examined. The tablets were fabricated by combining multi-walled carbon nanotubes (MWCNTs), sodium dodecyl sulfate (SDS), sodium phosphate monobasic (NaH2PO4), and sodium carbonate (Na2CO3). The effervescent tablets were formulated with MWCNTs, NaH2PO4, and Na2CO3 at a weight ratio of 1:5.1:2.26, respectively. These tablets were then immersed in distilled water (DW) and seawater (SW) to produce 0.05 vol.% to 0.15 vol.% MWCNT suspensions. Then, the dispersion stability, thermal conductivity, and crystal layer growth of the nanofluids were characterized. The results showed that the DW-based nanofluids were more stable than their SW-based counterparts. Additionally, the 0.05 vol.% DW-based suspension exhibited greater long-term stability than those of the 0.15 vol.% suspensions, whereas the SW-based nanofluid exhibited the opposite behaviour. The greatest increases in thermal conductivity were 3.29% and 3.13% for 0.15 vol.% MWCNTs in DW and SW, respectively. The crystallization process occurred in nanofluids that contained more than 0.05 vol.% MWCNTs and exhibited a greater growth rate in SW-based suspensions with high effervescent agent concentrations.

17.
Foods ; 13(15)2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39123612

RESUMO

There is a demand from the scientific, beekeeping and consumer sectors to characterize honey based on its botanical origin, as it provides unique and distinctive properties. Nevertheless, existing studies on the physicochemical properties and the sensorial profile of honey in relation to botanical origin remain insufficient. This study aimed to understand the relationships between sensory profile and various chemical compounds (minerals, sugars, water content and volatiles) of three monofloral honeys (Atractylis serratuloides, Retama sphaerocarpa and Eruca sativa) produced in Algeria using principal component analysis. Crystallization was detected as a distinctive attribute of Eruca and Atractylis honey. A candy aroma and odor with floral nuances, light color, crystallized state and the volatile compounds Alpha-Bisabolol and Beta-eudesmol characterized the Atractylis honey. Eruca honeys were distinguished by an animal and degraded odor, bitter taste, light color and the presence of Dimethyl trisulfide and Dimethyl tetrasulfide. Finally, a vegetal aroma, some saltiness and sourness, dark amber color, lower sugar content, higher K content and Lilac aldehyde and Lilac aldehyde D characterized Retama honeys.

18.
Polymers (Basel) ; 16(15)2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39125155

RESUMO

The formation of polylactide stereocomplex (sc-PLA), involving the blending of poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA), enhances PLA materials by making them stronger and more heat-resistant. This study investigated the competitive crystallization behavior of homocrystals (HCs) and stereocomplex crystals (SCs) in a 50/50 PLLA/PDLA blend with added polyethylene glycol (PEG). PEG, with molecular weights of 400 g/mol and 35,000 g/mol, was incorporated at concentrations ranging from 5% to 20% by weight. Differential scanning calorimetry (DSC) analysis revealed that PEG increased the crystallization temperature, promoted SC formation, and inhibited HC formation. PEG also acted as a plasticizer, lowering both melting and crystallization temperatures. The second heating DSC curve showed that the pure PLLA/PDLA blend had a 57.1% fraction of SC while adding 5% PEG with a molecular weight of 400 g/mol resulted in complete SC formation. In contrast, PEG with a molecular weight of 35,000 g/mol was less effective, allowing some HC formation. Additionally, PEG consistently promoted SC formation across various cooling rates (2, 5, 10, or 20 °C/min), demonstrating a robust influence under different conditions.

19.
ACS Biomater Sci Eng ; 10(8): 5300-5312, 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39087496

RESUMO

The development of well-adherent, amorphous, and bioactive glass coatings for metallic implants remains a critical challenge in biomedical engineering. Traditional bioactive glasses are susceptible to crystallization and exhibit a thermal expansion mismatch with implant materials. This study introduces a novel approach to overcome these limitations by employing systematic Na2O substitution with CaO in borosilicate glasses. In-depth structural analysis (MD simulations, Raman spectroscopy, and NMR) reveals a denser network with smaller silicate rings, enhancing thermal stability, reducing thermal expansion, and influencing dissolution kinetics. This tailored composition exhibited optimal bioactivity (in vitro formation of bone-like apatite within 3 days) and a coefficient of thermal expansion closely matching Ti-6Al-4V, a widely used implant material. Furthermore, a consolidation process, meticulously designed with insights from crystallization kinetics and the viscosity-temperature relationship, yielded a crack-free, amorphous coating on Ti-6Al-4V substrates. This novel coating demonstrates excellent cytocompatibility and strong antibacterial action, suggesting superior clinical potential compared with existing technologies.


Assuntos
Materiais Revestidos Biocompatíveis , Vidro , Titânio , Vidro/química , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Titânio/química , Próteses e Implantes , Antibacterianos/química , Antibacterianos/farmacologia , Teste de Materiais , Propriedades de Superfície , Ligas/química , Humanos
20.
Angew Chem Int Ed Engl ; : e202412515, 2024 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-39155244

RESUMO

Inverted perovskite/organic tandem solar cells (P/O TSCs) suffer from poor long-term device stability due to halide segregation in organic-inorganic hybrid wide-bandgap (WBG) perovskites, which hinders their practical deployment. Therefore, developing all-inorganic WBG perovskites for incorporation into P/O TSCs is a promising strategy because of their superior stability under continuous illumination. However, these inorganic WBG perovskites also face some critical issues, including rapid crystallization, phase instability, and large energy loss, etc. To tackle these issues, two multifunctional additives based on 9,10-anthraquinone-2-sulfonic acid (AQS) are developed to regulate the perovskite crystallization by mediating the intermediate phases and suppress the halide segregation through the redox-shuttle effect. By coupling with organic cations having the desirable functional groups and dipole moments, these additives can effectively passivate the defects and adjust the alignment of interface energy levels. Consequently, a record Voc approaching 1.3 V with high power conversion efficiency (PCE) of 18.59% could be achieved in a 1.78 eV bandgap single-junction inverted all-inorganic PSC. More importantly, the P/O TSC derived from this cell demonstrates a T90 lifetime of 1000 h under continuous operation, presenting the most stable P/O TSCs reported so far.

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