RESUMEN
Metal single atom catalysts (SAC) have been successfully used in heterogeneous catalysis but developing a scalable and economic support for SAC is still a great challenge. Here, cyclized polyacrylonitrile (CPAN) is proposed as a promising support for single atom metal catalysts. CPAN can be easily prepared from cheap industrial product polyacrylonitrile (PAN), which has excellent processability. A series of SAC on CPAN (M/CPAN, M = Ag, Cu, Ru) are designed and the catalytic activities of the as synthesized M/CPAN are investigated by the model reduction reaction of p-nitrophenol (4-NP). M/CPAN presents excellent catalytic performance with high stability and theoretical calculations elucidate that Ag/CPAN synergistically catalyze 4-NP reduction following the Langmuir-Hinshelwood (L-H) mechanism with 4-NP preferentially adsorbing at the Ag sites and H adsorbing at the bridge C sites. These results, for the first time, reveal that the single atom on CPAN can catalyze 4-NP reduction efficiently. This methodology provides a convenient route for the preparation of a variety of SAC, and this strategy is readily scalable and holds great potential in catalytic applications.
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Resinas Acrílicas , Metales , Catálisis , Dominio Catalítico , Metales/químicaRESUMEN
KEY MESSAGE: Two homologs PsnSuSy1 and PsnSuSy2 from poplar played largely similar but little distinct roles in modulating sink strength, accelerating vegetative growth and modifying secondary growth of plant. Co-overexpression of them together resulted in small but perceptible additive effects. Sucrose synthase (SuSy) acts as a crucial determinant of sink strength by controlling the conversion of sucrose into UDP-glucose, which is not only the sole precursor for cellulose biosynthesis but also an extracellular signaling molecule for plants growth. Therefore, modification of SuSy activity in plants is of utmost importance. We have isolated two SuSy genes from poplar, PsnSuSy1 and PsnSuSy2, which were preferentially expressed in secondary xylem/phloem. To investigate their functions, T2 tobacco transgenic lines of PsnSuSy1 and PsnSuSy2 were generated and then crossed to generate PsnSuSy1/PsnSuSy2 dual overexpression transgenic lines. SuSy activities in all lines were significantly increased though PsnSuSy1/PsnSuSy2 lines only exhibited slightly higher SuSy activities than either PsnSuSy1 or PsnSuSy2 lines. The significantly increased fructose and glucose, engendered by augmented SuSy activities, caused the alternations of many physiological, biochemical measures and phenotypic traits that include accelerated vegetative growth, thickened secondary cell wall, and increased stem breaking force, accompanied with altered expression levels of related pathway genes. The correlation relationships between SuSy activities and many of these traits were statistically significant. However, differences of almost all traits among three types of transgenic lines were insignificant. These findings clearly demonstrated that PsnSuSy1 and PsnSuSy2 had similar but little distinct functions and insubstantial additive effects on modulating sink strength and affecting allocation of carbon elements among secondary cell wall components.
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Pared Celular/metabolismo , Regulación de la Expresión Génica de las Plantas , Genes de Plantas/genética , Glucosiltransferasas/genética , Nicotiana/genética , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/genética , Pared Celular/ultraestructura , Celulosa/biosíntesis , Clorofila/análisis , Clonación Molecular , Perfilación de la Expresión Génica , Glucosiltransferasas/metabolismo , Lignina/metabolismo , Floema/metabolismo , Fotosíntesis , Polisacáridos/metabolismo , Populus/genética , Análisis de Secuencia , Sacarosa/metabolismo , Nicotiana/citología , Nicotiana/crecimiento & desarrollo , Xilema/metabolismoRESUMEN
BACKGROUND: Drug-eluting balloons (DEB) have significant value for treating coronary artery disease (CAD). However, the merits of using DEB versus drug-eluting stents (DES) to treat CAD remain controversial. Herein, we conducted a meta-analysis to compare the safety and efficacy of DEB and DES for treatment of CAD. METHODS: We searched MEDLINE, EMBASE, and CENTRAL databases for eligible trials comparing DEB with DES for treatment of CAD. The primary endpoint was major adverse cardiac events (MACE); the secondary endpoints included in-lesion late lumen loss (LLL), binary restenosis (BR), myocardial infarction (MI), target lesion revascularization (TLR) and mortality. RESULTS: Twenty-three trials with a total of 2712 patients were included. There were no significant differences in the primary endpoint of MACE between the DEB and DES groups (Risk Ratio (RR) 1.19; 95% confidence interval (CI) (0.87, 1.63); P = 0.27), or in the clinical outcomes of each of MACE's components, including TLR, MI and mortality. However, efficacy was significantly different between the DEB and DES groups, especially when we compared DEB to second-generation DES: in-lesion LLL (Mean Difference (MD) 0.11; (0.01, 0.22); P = 0.03); binary restenosis (RR 1.46; (1.00, 2.13); P = 0.05). CONCLUSIONS: DEB is equivalent to DES in terms of safety for managing CAD, and DEB may be considered as an alternative choice for treatment of CAD.
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Angioplastia Coronaria con Balón/instrumentación , Catéteres Cardíacos , Materiales Biocompatibles Revestidos , Enfermedad de la Arteria Coronaria/cirugía , Stents Liberadores de Fármacos , Angioplastia Coronaria con Balón/efectos adversos , Angioplastia Coronaria con Balón/mortalidad , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/mortalidad , Reestenosis Coronaria/etiología , Humanos , Infarto del Miocardio , Diseño de Prótesis , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Riesgo , Factores de Tiempo , Resultado del TratamientoRESUMEN
Polydopamine nanomaterials have emerged as one of the most popular organic materials for the management of oxidative stress-mediated inflammatory diseases. However, their current anti-inflammatory ability is still unsatisfactory because of limited phenolic hydroxyl groups, and oxidation reaction-medicated reactive oxygen and nitrogen species (RONS) scavenging. Herein, via fusing dimension engineering and surface charge engineering, 2D cationic polydopamine nanosheets (PDA NSs) capable of scavenging multiple danger signals to enhance anti-inflammatory capability are reported. Compared with conventional spherical polydopamine nanoparticles, 2D PDA NSs exhibit three- to fourfold enhancement in RONS scavenging capability, which should be attributed to high specific surface area and abundant phenol groups of 2D ultrathin structure. To further enhance the anti-inflammatory ability, polylysine molecules are absorbed on the surface of PDA NSs to endow the scavenging capability of cell-free DNA (cfDNA), another typical inflammatory factor to exacerbate the pathogenesis of inflammation. Molecular mechanisms reveal that cationic PDA NSs can concurrently activate Keap1-Nrf2 and block TLR9 signaling pathway, achieving synergistical inflammation inhibition. As a proof of concept, cationic PDA NSs with RONS and cfDNA dual-scavenging capability effectively alleviate the inflammatory bowel disease in both delayed and prophylactic models, much better than the clinical drug 5-aminosalicylic acid.
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Antiinflamatorios , Indoles , Polímeros , Polímeros/química , Indoles/química , Indoles/farmacología , Antiinflamatorios/química , Antiinflamatorios/farmacología , Animales , Ratones , Cationes/química , Especies Reactivas de Oxígeno/metabolismo , Nanoestructuras/química , Especies de Nitrógeno Reactivo/metabolismo , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Polilisina/química , Células RAW 264.7 , Nanopartículas/químicaRESUMEN
Supermacroporous composite cryogels with enhanced adjustable functionality have received extensive interest in bioseparation, tissue engineering, and drug delivery. However, the variations in their components significantly impactfinal properties. This study presents a two-step hybrid machine learning approach for predicting the properties of innovative poly(2-hydroxyethyl methacrylate)-poly(vinyl alcohol) composite cryogels embedded with bacterial cellulose (pHEMA-PVA-BC) based on their compositions. By considering the ratios of HEMA (1.0-22.0 wt%), PVA (0.2-4.0 wt%), poly(ethylene glycol) diacrylate (1.0-4.5 wt%), BC (0.1-1.5 wt%), and water (68.0-96.0 wt%) as investigational variables, overlay sampling uniform design (OSUD) was employed to construct a high-quality dataset for model development. The random forest (RF) model was used to classify the preparation conditions. Then four models of artificial neural network, RF, gradient boosted regression trees (GBRT), and XGBoost were developed to predict the basic properties of the composite cryogels. The results showed that the RF model achieved an accurate three-class classification of preparation conditions. Among the four models, the GBRT model exhibited the best predictive performance of the basic properties, with the mean absolute percentage error of 16.04 %, 0.85 %, and 2.44 % for permeability, effective porosity, and height of theoretical plate (1.0 cm/min), respectively. Characterization results of the representative pHEMA-PVA-BC composite cryogel showed an effective porosity of 81.01 %, a permeability of 1.20 × 10-12 m2, and a range of height of theoretical plate between 0.40-0.49 cm at flow velocities of 0.5-3.0 cm/min. These indicate that the pHEMA-PVA-BC cryogel was an excellent material with supermacropores, low flow resistance and high mass transfer efficiency. Furthermore, the model output demonstrates that the alteration of the proportions of PVA (0.2-3.5 wt%) and BC (0.1-1.5 wt%) components in composite cryogels resulted in significant changes in the material basic properties. This work represents an attempt to efficiently design and prepare target composite cryogels using machine learning and providing valuable insights for the efficient development of polymers.
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Celulosa , Criogeles , Aprendizaje Automático , Polihidroxietil Metacrilato , Alcohol Polivinílico , Criogeles/química , Alcohol Polivinílico/química , Polihidroxietil Metacrilato/química , Celulosa/química , Porosidad , Redes Neurales de la ComputaciónRESUMEN
Intestinal commensal microbiota dysbiosis and immune dysfunction are significant exacerbating factors in inflammatory bowel disease (IBD). To address these problems, Pluronic F-127-coated tungsten diselenide (WSe2 @F127) nanozymes are developed by simple liquid-phase exfoliation. The abundant valence transitions of elemental selenium (Se2- /Se4+ ) and tungsten (W4+ /W6+ ) enable the obtained WSe2 @F127 nanozymes to eliminate reactive oxygen/nitrogen species. In addition, the released tungsten ions are capable of inhibiting the proliferation of Escherichia coli. In a model of dextran sodium sulfate-induced colitis, WSe2 @F127 nanozymes modulate the gut microbiota by increasing the abundance of bacteria S24-7 and significantly reducing the abundance of Enterobacteriaceae. Moreover, WSe2 @F127 nanozymes inhibit T-cell differentiation and improve intestinal immune barrier function in a model of Crohn's disease. The WSe2 @F127 nanozymes effectively alleviate IBD by reducing oxidative stress damage, modulating intestinal microbial populations, and remodeling the immune barrier.
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Microbioma Gastrointestinal , Enfermedades Inflamatorias del Intestino , Polietilenos , Polipropilenos , Animales , Ratones , Tungsteno/farmacología , Enfermedades Inflamatorias del Intestino/tratamiento farmacológico , Enfermedades Inflamatorias del Intestino/microbiología , Escherichia coli , Especies Reactivas de Oxígeno , Diferenciación Celular , Modelos Animales de Enfermedad , Ratones Endogámicos C57BLRESUMEN
Wastewater treatment plants (WWTPs) receive large quantities of microplastics (MPs) from raw wastewater, but many MPs are trapped in the sludge. Land application of sludge is a significant source of MP pollution. Existing reviews have summarized the analysis methods of MPs in sludge and the effect of MPs on sludge treatments. However, MP aging and mitigation during sludge treatment processes are not fully reviewed. Treatment processes used to remove water, pathogenic microorganisms, and other pollutants in sewage sludge also cause surface changes and degradation in the sludge MPs, affecting the potential risk of MPs. This study integrates MP abundance and distribution in sludge and their aging and mitigation characteristics during sludge treatment processes. The abundance, composition, and distribution of sludge MPs vary significantly with WWTPs. Furthermore, MPs exhibit variable degrees of aging, including rough surfaces, enhanced adsorption potentials for pollutants, and increased leaching behavior. Various sludge treatment processes further intensify these aging characteristics. Some sludge treatments, such as hydrothermal treatment, have efficiently removed MPs from sewage sludge. It is crucial to understand the potential risk of MP aging in sludge and the degradation properties of the MP-derived products from MP degradation in-depth and develop novel MP mitigation strategies in sludge, such as combining hydrothermal treatment and biological processes.
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Contaminantes Ambientales , Contaminantes Químicos del Agua , Aguas del Alcantarillado , Microplásticos , Plásticos , Aguas Residuales , Contaminantes Químicos del Agua/análisis , Eliminación de Residuos LíquidosRESUMEN
Although two-dimensional (2D) materials with ultrathin geometry and extraordinary electrical attributes have attracted substantial concern, exploiting new-type 2D materials is still a great challenge. In this work, an unprecedented single-layer pure polyoxometalate (POM) 2D material (2D-1) was prepared by ultrasonically exfoliating a one-dimensional (1D)-chain heterometallic crystalline germanotungstate Na4[Ho(H2O)6]2[Fe4(H2O)2(pic)6Ge2W20O72]·16H2O (1) (Hpic = picolinic acid). The 1D polymeric chain of 1 is assembled from particular {Ge2W20}-based [Fe4(H2O)2(pic)6Ge2W20O72]10- segments through bridging [Ho(H2O)6]3+ cations. 2D-1 is formed by π-π interaction driving force among adjacent 1D polymeric chains of 1. Also, the peroxidase-mimicking properties of 2D-1 toward detecting H2O2 were evaluated and good detection result was observed with a limit of detection (LOD) of 58 nM. Density functional theory (DFT) calculation further confirms that 2D-1 displays outstanding catalytic activity and active sites are located on Fe centers and Hpic ligands. Under the catalysis of uricase, uric acid can be transformed to allantoin and H2O2, and then, H2O2 oxidizes TMB to its blue ox-TMB in the presence of 2D-1 as a catalyst. Then, we utilized this cascade reaction to detect uric acid, which also exhibits prominent results. This research opens a door to prepare ultrathin pure POM 2D materials and broadens the scope of potential applications of POMs in biology and iatrology.
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Peróxido de Hidrógeno , Peroxidasa , Peroxidasa/química , Peróxido de Hidrógeno/química , Ácido Úrico , Peroxidasas , Polímeros , Colorantes , Catálisis , Colorimetría/métodosRESUMEN
To construct a three-dimensional (3D) model of a tooth, multiple charge coupled device (CCD) cameras should be deployed in practice. Each CCD camera captures part of the tooth from a different angle. The images captured by different cameras must be registered to construct the relational 3D model. Sample consensus initial alignment (SAC-IA) algorithm is usually adopted, and fast point feature histograms (FPFH) descriptor is selected to calculate eigenvalues for different images. However, the original SAC-IA algorithm cannot satisfy a real-time application because of low efficiency and accuracy. According to the application of voxel nearest neighbor search in octree in 3D data search, this paper proposes an improved SAC-IA algorithm based on voxel nearest neighbor search to improve the efficiency and accuracy of the algorithm. The experimental results show that comparing to the traditional SAC-IA algorithm, the proposed algorithm based on voxel nearest neighbor search improves the efficiency by 20.95% and the registration accuracy by 24.95%. The improved algorithm can be deployed to construct a 3D model of a tooth as well as 3D model construction of other objects based on coded structured light.
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Algoritmos , Análisis por Conglomerados , Consenso , HumanosRESUMEN
A high protein retention polyethersulfone (PES) membrane was prepared by nonsolvent-induced phase separation and surface coating, which exhibited enhanced hemocompatibility and antioxidant stress performance. The cross-linked network was constructed by tannic acid (TA) and alpha-lipoic acid (α-LA) on the surface of the membrane, which controlled the pores to a reasonable size. The enrichment of heparin-like groups on the membrane surface, implemented by "hydrophobic interaction" and "click reaction", confers anticoagulant properties; the presence of a large number of phenolic hydroxyl groups from TA and the introduction of α-LA allows the modified membranes to intervene in oxidative stress. The hemocompatibility characterizations included plasma recalcification time (PRT), activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and hemolysis rate (HR). Additionally, the DPPH ABTS radical scavenging capacity was tested to evaluate the antioxidant performance. The results show that the modified membrane presents an outstanding protein retention rate (99.3%) along with permeability. In addition, the PRT is prolonged to 341.7 s, and the DPPH⢠scavenging ability reaches 0.74 µmolâ¢cm-2. The membranes can be easily prepared and present excellent comprehensive performance. This work provides a simple and facile strategy for the fabrication of hemodialysis membranes with controllable pore sizes.
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Membranas Artificiales , Taninos , Antioxidantes/farmacología , Proteínas/química , Diálisis Renal/métodosRESUMEN
Breast cancer is the most common tumor in female, which seriously threatens the health of women. Triple-negative breast cancer is a subtype with the worst prognosis because of its special physiological characteristics and lack of targeted drugs. Therefore, it is urgent to develop new targeted treatments to improve the prognosis and survival rate of the patients. Previous studies have shown that heat shock protein gp96 is expressed on the membrane of a variety of cancer cells but not on the normal cells. Cell membrane gp96 levels are closely related to the poor prognosis of breast cancer, which may serve as a new target for breast cancer treatment. Based on the structure of gp96, we designed an α-helical peptide p37 that specifically targeting the ATP binding region of gp96. To improve the stability and decrease the degradation of the peptide, the N-terminus or C-terminus of p37 was coupled to PEG2000 or PEG5000 respectively, and four PEGylated polypeptides were obtained: mPEG2000CY, mPEG5000CY, mPEG2000LC, and mPEG5000LC. The PEGylated polypeptides inhibited the proliferation and invasion of breast cancer cell SK-BR-3, among which mPEG2000CY showed the most significant inhibitory effect. The half-life of mPEG2000CY in vivo was significantly longer than p37, and it effectively inhibited the growth of xenografted tumors of triple-negative breast cancer MDA-MB-231. The results provide a basis for the development of new targeted drugs against breast cancer, especially the triple-negative breast cancer.
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Proteínas de Choque Térmico , Neoplasias de la Mama Triple Negativas , Adenosina Trifosfato , Femenino , Humanos , Péptidos/farmacología , Polietilenglicoles , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/patologíaRESUMEN
Sewage sludge is an important source for microplastics (MPs) entering into environment. Hydrothermal treatment has been considered a promising method for reducing MPs in sewage sludge. However, MPs degradation characteristics and mechanism during sludge hydrothermal treatment are not fully understood. In the study, three common MPs, i.e. polyethylene (PE), polystyrene (PS) and polyethylene terephthalate (PET) were used to explore the effect of hydrothermal treatment on the properties of MPs in sewage sludge. The hydrothermally-treated (HT) MPs in sludge feature more broken and rougher surfaces with higher O-containing functional groups in the sludge than those in water. The dissolved leachates from the HT MPs in the sludge show higher concentrations than the counterparts, implying that certain components in sludge serve to promote the MP degradation and leaching during hydrothermal treatment. Three model components in the sludge, including protein, carbohydrate, and SiO2, were further investigated for their individual effects on the hydrothermal degradation of MPs. Compared with those in water, the HT MPs in the protein and carbohydrate solutions show greater changes in the surface micro-morphologies and carbonyl index, and generate more leachates. However, the SiO2 solution results in similar difference in the MPs changes with the water solution, indicating that organic components of sludge play a more critical role in the enhanced MPs hydrothermal degradation than inorganic components. The HT PET leads to more pronounced changes in the physicochemical and leaching characteristics than the HT PE and PS, possibly due to more susceptible hydrolysis of the PET. Hydrothermal degradation of the MPs is found to be mainly driven by depolymerization of the polymer and leaching of the plastics additives. The findings imply that the sludge organic components significantly promote the MPs aging and degradation during hydrothermal treatment, and potential changes in the environmental risk of the treated MPs upon their subsequent land applications.
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Microplásticos , Aguas del Alcantarillado , Carbohidratos , Plásticos , Polietileno , Aguas del Alcantarillado/química , Dióxido de Silicio , AguaRESUMEN
Design and application of stimulus-responsive microgels is still in its infancy but is an exhilarating topic in controllable sensing device. Here, we have fabricated a dual-responsive platform capable of both sensitive on-spot fluorescence analysis and reliable surface-enhanced Raman scattering (SERS) quantification of water and temperature by in-situ encapsulating 4,4'-dimercaptoazobenzene (DMAB), meso-formyl-1,3,5,7-tetramethyl pyrromethene fluoroborate (FPF) probe and Ag nanoparticles (AgNPs) into polyvinyl alcohol (PVA) microgels. The smart microgels exhibit ultra-sensitive (detection limit 10-4% v/v) and reversible response towards water due to the liner relationship between network volume and SERS performance of the microgels. Furthermore, the presence of water triggers the conversion of FPF to aldehyde hydrate, facilitating visual assay of trace water in matrix samples through the enhanced fluorescence signals. Interestingly, the SERS signals can be precisely tuned by the thermo-sensitive microgels substrate, thus achieving the temperature monitoring from 32 to 50 °C. The microgels-based sensor has fast-response (2 min), excellent stability, and enables accurate and reliable response of water in organic solvent and pharmaceutical products. As a smart and flexible sensor, the hybrid microgels will facilitate the field of POC analysis, as well as molecular recognition in the future.
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Técnicas Biosensibles , Nanopartículas del Metal , Microgeles , Plata , Espectrometría Raman , Temperatura , AguaRESUMEN
Objective:To explore the predictive factors for asymptomatic airway hyperresponsivenessï¼AAHRï¼ in patients with chronic rhinosinusitis with nasal polypsï¼CRSwNPï¼. Methods:A total of 76 CRSwNP patients who were hospitalized in the Department of Otorhinolaryngology of Fenyang Hospital affiliated to Shanxi Medical University from May 2016 to October 2020 were retrospectively analyzed, including 40 patients in AAHR group and 36 patients in non-airway hyperresponsivenessï¼non-airway hyperresponsiveness, NAHRï¼ group. The clinical symptoms, CT score of paranasal sinuses, eosinophilï¼EOSï¼ count in peripheral blood and nasal polyp tissue were compared and analyzed. Logistic regression was used to analyze the risk factors of AAHR, and receiver operating characteristics curve was used to judge the predictive value of the parameters. Results:Compared with NAHR group, AAHR group had more symptoms of mouth breathing and postnasal drip, higher total score of CT in ethmoid sinus, sphenoid sinus, olfactory cleft, and more EOS count in peripheral blood and nasal polyp tissue. The differences were statistically significant. There was a positive correlation between EOS count in peripheral blood and in nasal polyp tissueï¼r=0.324, P<0.01ï¼. Postnasal drip, high posterior ethmoid sinusï¼PEï¼ score and nasal polyp tissue EOS count were risk factors for AAHR. The predictive value of nasal polyp tissue EOS count was higher than that of PE scoreï¼AUC=0.786 and 0.685, respectivelyï¼. When the PE score was ≥1.5, the sensitivity was 80.0% and the specificity was 55.6%. When the nasal polyp tissue EOS count was ≥5.67/HPF, the sensitivity was 82.5% and the specificity was 66.7%. Conclusion:The occurrence of AAHR in patients with CRSwNP was related to clinical symptoms, paranasal sinus CT score, peripheral and nasal polyp tissue EOS count. PE score and nasal polyp tissue EOS count can be used to predict AAHR, however nasal polyp tissue EOS has higher predictive value.
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Pólipos Nasales , Senos Paranasales , Rinitis , Sinusitis , Enfermedad Crónica , Eosinófilos , Humanos , Pólipos Nasales/complicaciones , Estudios Retrospectivos , Rinitis/complicaciones , Sinusitis/complicacionesRESUMEN
The purpose of this study is to offer a novel kind of polyurethane with improved surface blood compatibility for long-term implant biomaterials. In this work, the aliphatic poly(ester-urethane) (PEU) with uniform-size hard segments was prepared and the PEU surface was grafted with hydrophilic poly(ethylene glycol) (PEG). The PEU was obtained by chain-extension of poly(É-caprolactone) (PCL) with isocyanate-terminated urethane triblock. Free amino groups were introduced onto the surface of PEU film via aminolysis with hexamethylenediamine, and then the NH2-grafted PEU surfaces (PEU-NH2) were reacted with isocyanate-terminated monomethoxyl PEG (MPEG-NCO) to obtain the PEG-grafted PEU surfaces (PEU-PEG). Analysis by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography were performed to confirm the chemical structures of the chain extender, PCL, PEU, and PEU-PEG. Additionally, the influence of aminolysis on the physical-mechanical properties of PEU films was investigated. Two glass transition temperatures and a broad endothermic peak were observed in the differential scanning calorimetry curves of PEU, which demonstrated a microphase-separated and semicrystalline structure, respectively. The PEU-PEG film exhibited excellent mechanical properties with an ultimate stress of â¼39 MPa and an elongation at break of â¼1190%, which was slightly lower than that of PEU, indicating that the aminolysis has little influence on the tensile properties. Evaluation of the blood compatibility of the films by bovine serum albumin adsorption and the platelet adhesion test revealed that the PEG-grafted surface had improved resistance to protein adsorption and excellent resistance to platelet adhesion. In vitro degradation tests showed that the PEU-PEG film could maintain its mechanical properties for more than six months and only lost â¼25% weight after 18 months. Due to the excellent mechanical properties, good blood compatibility and slow degradability, this novel kind of polyurethane hold significant promise for long-term implant biomaterials, especially soft tissue augmentation and regeneration.
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Materiales Biocompatibles/química , Isocianatos/química , Polietilenglicoles/química , Poliuretanos/química , Adsorción , Animales , Materiales Biocompatibles/síntesis química , Bovinos , Interacciones Hidrofóbicas e Hidrofílicas , Isocianatos/síntesis química , Ensayo de Materiales , Adhesividad Plaquetaria , Polietilenglicoles/síntesis química , Poliuretanos/síntesis química , Conejos , Albúmina Sérica Bovina/química , Propiedades de Superficie , Resistencia a la TracciónRESUMEN
Wood formation is a biological process during which the most abundant lignocellulosic biomass on earth is produced. Although a number of transcription factors have been linked to the regulation of wood formation process, none of them has been demonstrated to be a higher hierarchical regulator that coordinately regulates secondary wall biosynthesis genes. Here, we identified a Populus gene, PsnSHN2, a counterpart of the Arabidopsis AP2/ERF type transcription factor, SHINE2. PsnSHN2 is predominantly expressed in xylem tissues and acted evidently as a high hierarchical transcriptional activator. Overexpression of PsnSHN2 in tobacco significantly altered the expression of both transcription factors and biosynthesis genes involved in secondary wall formation, leading to the thickened secondary walls and the changed cell wall composition. The most significant changes occurred in the contents of cellulose and hemicellulose that increased 37% and 28%, respectively, whereas the content of lignin that decreased 34%. Furthermore, PsnSHN2 activated or repressed the promoter activities of transcription factors involved in secondary wall biosynthesis and bound to five cis-acting elements enriched in the promoter regions of these transcription factors. Taken together, our results suggest PsnSHN2 coordinately regulate secondary wall formation through selective up/down-regulation of its downstream transcription factors that control secondary wall formation.
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Nicotiana/metabolismo , Proteínas de Plantas/genética , Populus/genética , Pared Celular , Celulosa/metabolismo , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Lignina/metabolismo , Proteínas de Plantas/metabolismo , Polisacáridos/metabolismo , Populus/metabolismo , Análisis de Secuencia de ADN , Análisis de Secuencia de Proteína , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Técnicas del Sistema de Dos Híbridos , Madera/genética , Madera/metabolismoRESUMEN
Nanosuspensions (NS) can enhance the saturation solubility and dissolution velocity of poorly soluble drugs. PEG as a non-ionic surfactant plays an important role in surface modification of nanoparticles for prolonging in vivo circulation. In this study, anti-solvent precipitation method was introduced to prepare gambogenic acid nanosuspensions (GNA-NS) with PVPK30 and PEG2000 as stabilizers to settle the disadvantages of GNA. The obtained nanoparticles were spherical with a mean particle size of 183.7 nm and a zeta potential of -22.8 mV. The entrapment efficiency and drug loading of the resultant formulation were 97.3 and 29.73%. X-ray diffraction analysis confirmed the amorphous phase of GNA in NS. Fourier transform infrared indicated there may be hydrogen bond interaction between the drug and excipients. After lyophilization of GNA-NS, the freeze-dried powder displayed sufficient long-term physical stability at 4 and 25 °C. In comparison to GNA solution, in vitro studies of GNA-NS showed much slower release and higher cytotoxicity in HepG2 cells. What's more, the pharmacokinetic study in rats revealed that the AUC0-∞ and t1/2 of GNA-NS were increased 2.63- and 1.77-fold than that of the reference formulation. Taken together, in vitro/in vivo evaluations showed NS would be an effectively strategy to change the poor aqueous solubility and prolong the half-life for GNA. The GNA-NS with enhanced bioavailability and drug efficacy provided a promising delivery system for the application of GNA.