Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 983
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Mass Spectrom Rev ; 43(3): 427-476, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37070280

RESUMO

Ever since the inception of synthetic polymeric materials in the late 19th century, the number of studies on polymers as well as the complexity of their structures have only increased. The development and commercialization of new polymers with properties fine-tuned for specific technological, environmental, consumer, or biomedical applications requires powerful analytical techniques that permit the in-depth characterization of these materials. One such method with the ability to provide chemical composition and structure information with high sensitivity, selectivity, specificity, and speed is mass spectrometry (MS). This tutorial review presents and exemplifies the various MS techniques available for the elucidation of specific structural features in a synthetic polymer, including compositional complexity, primary structure, architecture, topology, and surface properties. Key to every MS analysis is sample conversion to gas-phase ions. This review describes the fundamentals of the most suitable ionization methods for synthetic materials and provides relevant sample preparation protocols. Most importantly, structural characterizations via one-step as well as hyphenated or multidimensional approaches are introduced and demonstrated with specific applications, including surface sensitive and imaging techniques. The aim of this tutorial review is to illustrate the capabilities of MS for the characterization of large, complex polymers and emphasize its potential as a powerful compositional and structural elucidation tool in polymer chemistry.

2.
Small ; 20(13): e2306154, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37967353

RESUMO

Hierarchical superstructures have novel shape-dependent properties, but well-defined anisotropic carbon superstructures with controllable size, shape, and building block dimensionality have rarely been accomplished thus far. Here, a hierarchical assembly technique is presented that uses spinodal decomposition (SD) to synthesize anisotropic oblate particles of mesoporous carbon superstructure (o-MCS) with nanorod arrays by integrating block-copolymer (BCP) self-assembly and polymer-polymer interface behaviors in binary blends. The interaction of major and minor phases in binary polymer blends leads to the formation of an anisotropic oblate particle, and the BCP-rich phase enables ordered packing and unidirectional alignment of carbon nanorods. Consequently, this approach enables precise control over particles' size, shape, and over the dimensionality of their components. Exploiting this functional superstructure, o-MCS are used as an anode material in potassium-ion batteries, and achieve a notable specific capacity of 156 mA h g-1 at a current density of 2 A g-1, and long-term stability for 3000 cycles. This work presents a significant advancement in the field of hierarchical superstructures, providing a promising strategy for the design and synthesis of anisotropic carbon materials with controlled properties, offering promising applications in energy storage and beyond.

3.
Amino Acids ; 56(1): 8, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38315260

RESUMO

Plant-derived proteins are generally believed to possess lesser anabolic properties when compared with animal-derived proteins. This is, at least partly, attributed to the lower leucine content of most plant-derived proteins. Corn protein has a leucine content that is highest among most plant-derived proteins and it even exceeds the levels observed in animal-derived proteins such as whey protein. Therefore, this study aimed to compare muscle protein synthesis rates following the ingestion of 30 g corn protein and a 30 g blend of corn plus milk protein with 30 g milk protein. In a randomized, double blind, parallel-group design, 36 healthy young males (26 ± 4 y) received primed continuous L-[ring-13C6]-phenylalanine infusions and ingested 30 g corn protein (CORN), 30 g milk protein (MILK), or a 30 g proteinblend with 15 g corn plus 15 g milk protein (CORN + MILK). Blood and muscle biopsies were collected for 5 h following protein ingestion to assess post-prandial plasma amino acid profiles and myofibrillar protein synthesis rates. The results show that Ingestion of protein increased myofibrillar protein synthesis rates from basal post-absorptive values in all treatments(P < 0.001). Post-prandial myofibrillar protein synthesis rates did not differ between CORN vs MILK (0.053 ± 0.013 vs 0.053 ± 0.013%∙h-1, respectively; t-test P = 0.90), or between CORN + MILK vs MILK (0.052 ± 0.024 vs 0.053 ± 0.013%∙h-1, respectively; t-test P = 0.92). Ingestion of 30 g corn protein, 30 g milk protein, or a blend of 15 g corn plus 15 g milk protein robustly increases muscle protein synthesis rates in young males. The muscle protein synthetic response to the ingestion of 30 g corn-derived protein does not differ from the ingestion of an equivalent amount of milk protein in healthy, young males. Clinical Trial Registry number. NTR6548 (registration date: 27-06-2017) https://www.trialregister.nl/ .


Assuntos
Proteínas do Leite , Proteínas Musculares , Masculino , Proteínas Alimentares/metabolismo , Ingestão de Alimentos , Leucina/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Proteínas de Plantas/metabolismo , Zea mays/metabolismo , Humanos , Adulto Jovem , Adulto
4.
Mol Pharm ; 21(9): 4589-4602, 2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39088435

RESUMO

Amorphous solid dispersion (ASD) in a polymer matrix is a powerful method for enhancing the solubility and bioavailability of otherwise crystalline, poorly water-soluble drugs. 6-Carboxycellulose acetate butyrate (CCAB) is a relatively new commercial cellulose derivative that was introduced for use in waterborne coating applications. As CCAB is an amphiphilic, carboxyl-containing, high glass transition temperature (Tg) polymer, characteristics essential to excellent ASD polymer performance, we chose to explore its ASD potential. Structurally diverse drugs quercetin, ibuprofen, ritonavir, loratadine, and clarithromycin were dispersed in CCAB matrices. We evaluated the ability of CCAB to create ASDs with these drugs and its ability to provide solubility enhancement and effective drug release. CCAB/drug dispersions prepared by spray drying were amorphous up to 25 wt % drug, with loratadine remaining amorphous up to 50% drug. CCAB formulations with 10% drug proved effective at providing in vitro solubility enhancement for the crystalline flavonoid drug quercetin as well as ritonavir, but not for the more soluble APIs ibuprofen and clarithromycin and the more hydrophobic loratadine. CCAB did provide slow and controlled release of ibuprofen, offering a simple and promising Long-duration ibuprofen formulation. Formulation with clarithromycin showed the ability of the polymer to protect against degradation of the drug at stomach pH. Furthermore, CCAB ASDs with both loratadine and ibuprofen could be improved by the addition of the water-soluble polymer poly(vinylpyrrolidone) (PVP), with which CCAB shows good miscibility. CCAB provided solubility enhancement in some cases, and the slower drug release exhibited by CCAB, especially in the stomach, could be especially beneficial, for example, in formulations containing known stomach irritants like ibuprofen.


Assuntos
Celulose , Ibuprofeno , Loratadina , Polímeros , Solubilidade , Polímeros/química , Celulose/química , Celulose/análogos & derivados , Ibuprofeno/química , Ibuprofeno/farmacocinética , Loratadina/química , Loratadina/análogos & derivados , Loratadina/farmacocinética , Liberação Controlada de Fármacos , Quercetina/química , Claritromicina/química , Ritonavir/química , Química Farmacêutica/métodos , Composição de Medicamentos/métodos
5.
Crit Rev Food Sci Nutr ; : 1-19, 2024 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-39154209

RESUMO

In recent years, the worldwide increase in lifestyle diseases and metabolic disorders has been ascribed to the excessive consumption of sucrose and added sugars. For this reason, many approaches have been developed in order to replace sucrose in food and beverage formulations with alternative sweetening compounds. The raising awareness concerning the synthetic sweeteners due to their negative impact on health, triggered the need to search for alternative substances. Natural sweeteners may be classified in: (i) non-nutritive (e.g., neohesperidine dihydrochalcone, thaumatin, glycyrrhizin mogroside and stevia) and (ii) bulk sweeteners, including both polyols (e.g., maltitol, mannitol, erythritol) and rare sugars (e.g., tagatose and allulose). In this review we discuss the most popular natural sweeteners and their application in the main food sectors (e.g., bakery, dairy, confectionary and beverage), providing a full understanding of their impact on the textural and sensory properties in comparison to sucrose. Furthermore, we analyze the use of natural sweeteners in blends, which in addition to enabling an effective replacement of sugar, in order to complement the merits and limits of individual compounds. Finally, microencapsulation technology is presented as an alternative strategy to solving some issues such as aftertaste, bitterness, unpleasant flavors, but also to enhance their stability and ease of use.

6.
Macromol Rapid Commun ; 45(11): e2400036, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38453138

RESUMO

Preparation of materials that possess highly strong and tough properties simultaneously is a great challenge. Thermosetting resins as a type of widely used polymeric materials without synergistic strength and toughness limit their applications in some special fields. In this report, an effective strategy to prepare thermosetting resins with synergistic strength and toughness, is presented. In this method, the soft and rigid microspheres with dynamic hemiaminal bonds are fabricated first, followed by hot-pressing to crosslink at the interfaces. Specifically, the rigid or soft microspheres are prepared via precipitation polymerization. After hot-pressing, the resulting rigid-soft blending materials exhibit superior strength and toughness, simultaneously. As compared with the precursor rigid or soft materials, the toughness of the rigid-soft blending films (RSBFs) is improved to 240% and 2100%, respectively, while the strength is comparable to the rigid precursor. As compared with the traditional crushing, blending, and hot-pressing of rigid or soft materials to get the nonuniform materials, the strength and toughness of the RSBFs are improved to 168% and 255%, respectively. This approach holds significant promise for the fabrication of polymer thermosets with a unique combination of strength and toughness.


Assuntos
Polimerização , Resinas Sintéticas/química , Microesferas , Polímeros/química , Temperatura , Teste de Materiais , Propriedades de Superfície , Tamanho da Partícula
7.
Macromol Rapid Commun ; : e2400551, 2024 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-39183577

RESUMO

Binary blends of polyterpenes are employed comprising cis-1,4-polyfarnesene (PF) with a bottlebrush architecture, and linear cis-1,4-polyisoprene (PI) as model systems toward supersoft polymer melts. The bottlebrush PF results in a low plateau modulus ( G N 0 ≈ 3.5 × 10 4 ${G}_{N}^{0}\approx 3.5\ensuremath{\times{}}{10}^{4}$ Pa) that can further be reduced with the addition of PI. Depending on the fraction of short PI chains in the athermal and nearly isofrictional blends, plateau moduli in the range from 1 to 10 kPa can be achieved. Tube dilation is very efficient in the present binary blends as compared to more common blends comprising long/short or linear/star chains of identical polymer structure.

8.
Chem Biodivers ; : e202401076, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38899851

RESUMO

This study reports on the chemical composition and antileishmanial and anticandidal activities of volatile oils (VOs) of Schinus molle dried leaves (SM), Cinnamomum cassia branch bark (CC) and their blends. Major constituents of SM were spathulenol (26.93 %), ß-caryophyllene (19.90 %), and caryophyllene oxide (12.69 %), whereas (E)-cinnamaldehyde (60.11 %), cinnamyl acetate (20.90 %) and cis-2-methoxycinnamic acid (10.37 %) were predominant in CC. SM (IC50=21.45 µg/mL) and CC (IC50=23.27 µg/mL) displayed good activity against L. amazonensis promastigotes, besides having good or moderate activity against nine Candida strains, with Minimum Inhibitory Concentration (MIC) values ranging from 31.25 to 250 µg/mL. While the three SM and CC blends were not more active than the VOs tested individually, they exhibited remarkably high antileishmanial activity, with IC50 values ranging between 3.12 and 7.04 µg/mL, which is very similar to the IC50 of amphotericin B (positive control).

9.
Bioprocess Biosyst Eng ; 47(8): 1293-1306, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38568262

RESUMO

Plant-mediated solution casting is used to develop eco-friendly polymer blend nanocomposites from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) doped with Silver (Ag), Ferrous (Fe) monometallic and Silver-Ferrous (Ag-Fe) bimetallic nanoparticles (NPs). These nanocomposites were studied to understand their electromagnetic interface (EMI) shielding efficiency and antimicrobial activities, besides evaluating their physical and chemical properties. The Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX) characterization techniques were used to examine the interactions between the polymers, the presence of silver and ferrous particles in the composites, the crystallinity shift, the surface morphology, the shape and size of the nanoparticles and the distribution of the nanoparticles in the composites. The FTIR spectra showed the interactions among the components of the composites. According to XRD spectra, the incorporation of nanoparticles into the PVA polymer significantly reduced the crystalline character of the polymer from 0.38 to 0.24 for the composition consisting of silver and iron nanoparticles in equal proportion. The results from SEM, EDX and XRD corroborate the presence of nanoparticle forms. The thermogravimetric analysis (TGA) tests reveal that the thermal stability of bimetallic composites is greater than that of monometallic composites. The tensile properties showed that the addition of nanoparticles to the PVA/PVP polymer matrix increased its mechanical strength from 59.3 MPa to 85.5 MPa. We examined its efficacy against Escherichia coli, Staphylococcus aureus and Candida albicans as microorganisms. Good antibacterial and antifungal activity was observed. The bimetallic composites demonstrated greater activity than monometallic composites against these bacterial and fungal species. All bimetallic nanocomposites have shown enhanced, loss due to reflection, loss due to absorption, and the total EMI shielding efficiency at 8 GHz (X-band) and 16 GHz (Ku-band) frequency. All these results ratify, that these newly developed bio nanocomposites are most suitable in many applications, in EMI shielding, nanotechnology, and medical fields.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Nanocompostos , Prata , Nanocompostos/química , Nanopartículas Metálicas/química , Prata/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Biopolímeros/química , Álcool de Polivinil/química , Ferro/química , Química Verde , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Testes de Sensibilidade Microbiana , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
10.
Int J Food Sci Nutr ; 75(1): 70-80, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37933669

RESUMO

To identify the potential anabolic properties of a dairy-plant protein blend as compared to single plant-based and single dairy protein, the postprandial amino acid (AA) response of pea protein, milk protein, micellar casein, and a casein-pea protein blend was investigated in healthy older adults (age 72.3 ± 3.4 years, BMI 25.3 ± 2.9 kg/m2). Plasma AA levels were measured, before and up to 5 h after ingestion of each 20 g protein. Blending casein-pea in a 60/40 mixture resulted in improved plasma AA availability, i.e. area under the curve (AUC) and peak height, of total (essential) AA and of key AAs methionine and leucine compared to pea only, while preserving the higher availability of arginine. The casein/pea blend clearly showed an AA response that was in between that of its single constituents, indicating that blending could be a solution to improve a lower quality (plant) protein, which could be of relevance for older adults.


Assuntos
Aminoácidos , Proteínas de Ervilha , Caseínas/química , Proteínas do Leite , Pisum sativum , Proteínas de Plantas , Ingestão de Alimentos , Período Pós-Prandial
11.
J Environ Manage ; 366: 121931, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39033620

RESUMO

The global demand for petroleum-derived plastics continues to increase, as does pollution caused by plastic consumption and landfilling plastic waste. Recycling waste plastics by thermomechanical molding may be advantageous, but it alone cannot address the challenges associated with plastic demand and its widespread pollution. A more sustainable and cleaner approach for recycling plastic waste could be to produce thermoplastic composite blends of waste plastic and biobased alternative materials such as marine algal biomass. In this study, Geitlerinema sp., a marine cyanobacterium, was cultivated with waste nitrogen fertilizer as a nitrogen source, resulting in phycocyanin content and biomass density of 6.5% and 0.7 g/L, respectively. The minimum and maximum tensile strengths of thermoplastic blends containing Geitlerinema sp. biomass, recycled glycerol plasticizer, and waste plastic were 0.29-23.2 MPa, respectively. The tensile strength and Young's modulus of thermoplastic composites decreased as the Geitlerinema sp. biomass concentration increased. Furthermore, thermal analysis revealed that thermoplastics containing Geitlerinema sp. biomass have lower thermal onset and biomass degradation temperatures than waste polyethylene. Nevertheless, 35-50% of Geitlerinema sp. biomass could be a sustainable biobased alternative feedstock for producing thermoplastic blends, making the recycling of waste plastics more sustainable and environmentally friendly.


Assuntos
Cianobactérias , Fertilizantes , Nitrogênio , Plásticos , Cianobactérias/crescimento & desenvolvimento , Cianobactérias/metabolismo , Biomassa , Reciclagem
12.
Molecules ; 29(18)2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39339284

RESUMO

Current transdermal drug delivery technologies, like patches and ointments, effectively deliver low molecular weight drugs through the skin. However, delivering larger, hydrophilic drugs and macromolecules remains a challenge. In the present study, we developed novel transdermal nanoneedle patches containing levofloxacin-loaded modified chitosan nanoparticles. Chitosan was chemically modified with transcutol in three ratios (1/1, 1/2, 1/3, w/w), and the optimum ratio was used for nanoparticle fabrication via the ionic gelation method. The successful modification was confirmed using ATR-FTIR spectroscopy, while DLS results revealed that only the 1/3 ratio afforded suitably sized particles of 220 nm. After drug encapsulation, the particle size increased to 435 nm, and the final formulations were examined via XRD and an in vitro dissolution test, which suggested that the nanoparticles reach 60% release in a monophasic pattern at 380 h. We then prepared transdermal patches with pyramidal geometry nanoneedles using different poly(lactic acid)/poly(ethylene adipate) (PLA/PEAd) polymer blends of varying ratios, which were characterized in terms of morphology and mechanical compressive strength. The 90/10 blend exhibited the best mechanical properties and was selected for further testing. Ex vivo permeation studies proved that the nanoneedle patches containing drug-loaded nanoparticles achieved the highest levofloxacin permeation (88.1%).


Assuntos
Administração Cutânea , Quitosana , Levofloxacino , Nanopartículas , Poliésteres , Levofloxacino/administração & dosagem , Levofloxacino/química , Quitosana/química , Nanopartículas/química , Poliésteres/química , Animais , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Tamanho da Partícula , Adesivo Transdérmico , Liberação Controlada de Fármacos , Antibacterianos/administração & dosagem , Antibacterianos/química , Absorção Cutânea , Pele/metabolismo
13.
Molecules ; 29(16)2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39202905

RESUMO

Bone tissue exhibits self-healing properties; however, not all defects can be repaired without surgical intervention. Bone tissue engineering offers artificial scaffolds, which can act as a temporary matrix for bone regeneration. The aim of this study was to manufacture scaffolds made of poly(lactic acid), poly(ε-caprolactone), poly(propylene fumarate), and poly(ethylene glycol) modified with bioglass, beta tricalcium phosphate (TCP), and/or wollastonite (W) particles. The scaffolds were fabricated using a gel-casting method and observed with optical and scanning electron microscopes. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG), wettability, and degradation tests were conducted. The highest content of TCP without W in the composition caused the highest hydrophilicity (water contact angle of 61.9 ± 6.3°), the fastest degradation rate (7% mass loss within 28 days), moderate ability to precipitate CaP after incubation in PBS, and no cytotoxicity for L929 cells. The highest content of W without TCP caused the highest hydrophobicity (water contact angle of 83.4 ± 1.7°), the lowest thermal stability, slower degradation (3% mass loss within 28 days), and did not evoke CaP precipitation. Moreover, some signs of cytotoxicity on day 1 were observed. The samples with both TCP and W showed moderate properties and the best cytocompatibility on day 4. Interestingly, they were covered with typical cauliflower-like hydroxyapatite deposits after incubation in phosphate-buffered saline (PBS), which might be a sign of their excellent bioactivity.


Assuntos
Engenharia Tecidual , Alicerces Teciduais , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Animais , Materiais Biocompatíveis/química , Osso e Ossos/efeitos dos fármacos , Camundongos , Polímeros/química , Linhagem Celular , Poliésteres/química , Teste de Materiais , Cerâmica/química , Fosfatos de Cálcio/química , Regeneração Óssea/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Fumaratos/química
14.
Molecules ; 29(7)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38611707

RESUMO

Methanol-gasoline blends have emerged as a promising and environmentally friendly bio-fuel option, garnering widespread attention and promotion globally. The methanol content within these blends significantly influences their quality and combustion performance. This study explores the qualitative and qualitative analysis of methanol-gasoline blends using Raman spectroscopy coupled with machine learning methods. Experimentally, methanol-gasoline blends with varying methanol concentrations were artificially configured, commencing with initial market samples. For qualitative analysis, the partial least squares discriminant analysis (PLS-DA) model was employed to classify the categories of blends, demonstrating high prediction performance with an accuracy of nearly 100% classification. For the quantitative analysis, a consensus model was proposed to accurately predict the methanol content. It integrates member models developed on clustered variables, using the unsupervised clustering method of the self-organizing mapping neural network (SOM) to accomplish the regression prediction. The performance of this consensus model was systemically compared to that of the PLS model and uninformative variable elimination (UVE)-PLS model. Results revealed that the unsupervised consensus model outperformed other models in predicting the methanol content across various types of methanol gasoline blends. The correlation coefficients for prediction sets consistently exceeded 0.98. Consequently, Raman spectroscopy emerges as a suitable choice for both qualitative and quantitative analysis of methanol-gasoline blend quality. This study anticipates an increasing role for Raman spectroscopy in analysis of fuel composition.

15.
Ceska Slov Farm ; 73(1): 214-222, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38185644

RESUMO

The formulation of microparticles composed of a mixture of carriers represents an innovative approach for lung drug delivery of dry powder. The carriers used can significantly influence the properties of the microparticles, such as size, shape, surface area, hygroscopicity, or aggregation, thus improving the aerosolization of the drugs after inhalation. The properties mentioned above are crucial for effective  pulmonary  therapy. The  combination of carriers of a carbohydrate nature and gelling agents is advantageous for controlled drug release. The experimental work aimed to prepare by spray drying and subsequently evaluate ten batches of microparticles composed of sugar-based carriers (mannitol, maltodextrin, dextran) and gelling polymers (chitosan, chondroitin sulfate) and to select a suitable combination for follow-up experimental work aimed at drug incorporation into the microparticle matrix. The most suitable parameters were exhibited by batches whose aerodynamic diameter was close to 5 µm, particles prepared from a combination of mannitol and dextran, chitosan and chondroitin, or maltodextrin and chondroitin. These batches also showed the highest fine particle fraction value (> 43%). From a processability point of view, the batch with maltodextrin and chondroitin is preferable due to the lower viscosity of the dispersion and the more regular shape of the final microparticles.


Assuntos
Quitosana , Dextranos , Sistemas de Liberação de Medicamentos , Condroitina , Manitol
16.
Ceska Slov Farm ; 72(5): 214-222, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38195429

RESUMO

The formulation of microparticles composed of a mixture of carriers represents an innovative approach for lung drug delivery of dry powder. The carriers used can significantly influence the properties of the microparticles, such as size, shape, surface area, hygroscopicity, or aggregation, thus improving the aerosolization of the drugs after inhalation. The properties mentioned above are crucial for effective  pulmonary  therapy. The  combination of carriers of a carbohydrate nature and gelling agents is advantageous for controlled drug release. The experimental work aimed to prepare by spray drying and subsequently evaluate ten batches of microparticles composed of sugar-based carriers (mannitol, maltodextrin, dextran) and gelling polymers (chitosan, chondroitin sulfate) and to select a suitable combination for follow-up experimental work aimed at drug incorporation into the microparticle matrix. The most suitable parameters were exhibited by batches whose aerodynamic diameter was close to 5 µm, particles prepared from a combination of mannitol and dextran, chitosan and chondroitin, or maltodextrin and chondroitin. These batches also showed the highest fine particle fraction value (> 43%). From a processability point of view, the batch with maltodextrin and chondroitin is preferable due to the lower viscosity of the dispersion and the more regular shape of the final microparticles.


Assuntos
Quitosana , Dextranos , Sistemas de Liberação de Medicamentos , Condroitina , Manitol
17.
Angew Chem Int Ed Engl ; 63(20): e202317264, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38407469

RESUMO

Polymer compatibilization plays a critical role in achieving polymer blends with favorable mechanical properties and enabling efficient recycling of mixed plastic wastes. Nonetheless, traditional compatibilization methods often require tailored designs based on the specific chemical compositions of the blends. In this study, we propose a new approach for compatibilizing polymer blends using a dynamically crosslinked polymer network, known as vitrimers. By adding a relatively small amount (1-5 w/w%) of a vitrimer made of siloxane-crosslinked high-density polyethylene (HDPE), we successfully compatibilized unmodified HDPE and isotactic polypropylene (iPP). The vitrimer-compatibilized blend exhibited enhanced elongation at break (120 %) and smaller iPP domain sizes (0.4 µm) compared to the control blend (22 % elongation at break, 0.9 µm iPP droplet size). Moreover, the vitrimer-compatibilized blend showed significantly improved microphase stability during annealing at 180 °C. This straightforward method shows promise for applications across various polymer blend systems.

18.
Small ; 19(36): e2302127, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37116119

RESUMO

Processing additive plays an important role in the standard operation procedures for fabricating top performing polymer solar cells (PSCs) through efficient interactions with key photovoltaic materials. However, improving interaction study of acceptor materials to high performance halogenated aromatic additives such as diiodobenzene (DIB) is a widely neglected route for molecular engineering toward more efficient device performances. In this work, two novel Y-type acceptor molecules of BTP-TT and BTP-TTS with different aromatic side chains on the outer positions are designed and synthesized. The resulting aromatic side chains significantly enhanced the interactions between the acceptor molecules and DIB through an arene/halogenated arene interaction, which improved the crystallinity of the acceptor molecules and induced a polymorph with better photovoltaic performances. Thus, high power conversion efficiencies (PCEs) of 18.04% and 19.22% are achieved in binary and ternary blend devices using BTP-TTS as acceptor and DIB as additive. Aromatic side chain engineering for improving additive interactions is proved to be an effective strategy for achieving much higher performance photovoltaic materials and devices.

19.
J Nutr ; 153(5): 1305-1308, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37004873

RESUMO

This paper discusses the rationale for use of proprietary blends on dietary supplement labels, and their implications for researchers and consumers. The Dietary Supplement Health Education Act of 1994 allows the listing of nonnutrient dietary ingredients as proprietary blends on dietary supplement labels for companies to protect their unique formulas. The weight of the blend and names of the ingredients within the blends must be declared, but not the amounts of the individual ingredients within the proprietary blend. Thus, from label information, the amount of a dietary ingredient in a proprietary blend is not available for calculating exposures in assessments of intakes or for determining doses in clinical trials.


Assuntos
Suplementos Nutricionais , Educação em Saúde
20.
J Nutr ; 152(12): 2734-2743, 2023 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-36170964

RESUMO

BACKGROUND: Plant-derived proteins are considered to have lesser anabolic properties when compared with animal-derived proteins. The attenuated rise in muscle protein synthesis rates following ingestion of plant-derived compared with animal-derived protein has been, at least partly, attributed to deficiencies in specific amino acids such as leucine, lysine, and/or methionine. Combining different plant-derived proteins could provide plant-derived protein blends with a more balanced amino acid profile. OBJECTIVES: This study aimed to compare postprandial muscle protein synthesis rates following the ingestion of 30 g milk protein with a 30 g blend combining wheat, corn, and pea protein in healthy young men. METHODS: In a randomized, double-blind, parallel-group design, 24 young males (aged 24 ± 4 y) received a primed continuous l-[ring-13C6]-phenylalanine infusion after which they ingested 30 g milk protein (MILK) or a 30 g plant-derived protein blend combining 15 g wheat, 7.5 g corn, and 7.5 g pea protein (PLANT-BLEND). Blood and muscle biopsies were collected frequently for 5 h to assess postprandial plasma amino acid profiles (secondary outcome) and subsequent muscle protein synthesis rates (primary outcome). Data were analyzed by 2-factor repeated measures ANOVA and 2-samples t tests. RESULTS: MILK increased plasma essential amino acid concentrations more than PLANT-BLEND over the 5 h postprandial period (incremental AUC = 151 ± 31 compared with 79 ± 12 mmol·300 min·L-1, respectively; P < 0.001). Ingestion of both MILK and PLANT-BLEND increased myofibrillar protein synthesis rates (P < 0.001), with no significant differences between treatments (0.053 ± 0.013%/h and 0.064 ± 0.016%/h, respectively; P = 0.08). CONCLUSIONS: Ingestion of 30 g plant-derived protein blend combining wheat-, corn-, and pea-derived protein increases muscle protein synthesis rates in healthy young males. The muscle protein synthetic response to the ingestion of 30 g of this plant-derived protein blend does not differ from the ingestion of an equivalent amount of a high-quality animal-derived protein.Clinical trial registry number for Nederlands Trial Register: NTR6548 (https://trialsearch.who.int/Trial2.aspx?TrialID=NTR6548).


Assuntos
Proteínas do Leite , Proteínas de Ervilha , Animais , Masculino , Aminoácidos/metabolismo , Proteínas Alimentares/metabolismo , Ingestão de Alimentos , Proteínas do Leite/farmacologia , Proteínas do Leite/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Proteínas de Ervilha/metabolismo , Proteínas de Plantas/metabolismo , Período Pós-Prandial , Método Duplo-Cego
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA