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1.
Proc Natl Acad Sci U S A ; 118(11)2021 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-33729990

RESUMEN

Cellulose is synthesized by cellulose synthases (CESAs) from the glycosyltransferase GT-2 family. In plants, the CESAs form a six-lobed rosette-shaped CESA complex (CSC). Here we report crystal structures of the catalytic domain of Arabidopsis thaliana CESA3 (AtCESA3CatD) in both apo and uridine diphosphate (UDP)-glucose (UDP-Glc)-bound forms. AtCESA3CatD has an overall GT-A fold core domain sandwiched between a plant-conserved region (P-CR) and a class-specific region (C-SR). By superimposing the structure of AtCESA3CatD onto the bacterial cellulose synthase BcsA, we found that the coordination of the UDP-Glc differs, indicating different substrate coordination during cellulose synthesis in plants and bacteria. Moreover, structural analyses revealed that AtCESA3CatD can form a homodimer mainly via interactions between specific beta strands. We confirmed the importance of specific amino acids on these strands for homodimerization through yeast and in planta assays using point-mutated full-length AtCESA3. Our work provides molecular insights into how the substrate UDP-Glc is coordinated in the CESAs and how the CESAs might dimerize to eventually assemble into CSCs in plants.


Asunto(s)
Proteínas de Arabidopsis/química , Arabidopsis/química , Celulosa/metabolismo , Glucosiltransferasas/química , Uridina Difosfato Glucosa/química , Aminoácidos , Arabidopsis/enzimología , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Dominio Catalítico , Cristalografía por Rayos X , Glucosiltransferasas/genética , Glucosiltransferasas/metabolismo , Manganeso/química , Manganeso/metabolismo , Mutación , Multimerización de Proteína , Uridina Difosfato Glucosa/metabolismo
2.
J Exp Bot ; 74(4): 1207-1220, 2023 02 13.
Artículo en Inglés | MEDLINE | ID: mdl-36377754

RESUMEN

When attacked by herbivores, plants produce electrical signals which can activate the synthesis of the defense mediator jasmonate. These wound-induced membrane potential changes can occur in response to elicitors that are released from damaged plant cells. We list plant-derived elicitors of membrane depolarization. These compounds include the amino acid l-glutamate (Glu), a potential ligand for GLUTAMATE RECEPTOR-LIKE (GLR) proteins that play roles in herbivore-activated electrical signaling. How are membrane depolarization elicitors dispersed in wounded plants? In analogy with widespread turgor-driven cell and organ movements, we propose osmoelectric siphon mechanisms for elicitor transport. These mechanisms are based on membrane depolarization leading to cell water shedding into the apoplast followed by membrane repolarization and water uptake. We discuss two related mechanisms likely to occur in response to small wounds and large wounds that trigger leaf-to-leaf electrical signal propagation. To reduce jasmonate pathway activation, a feeding insect must cut through tissues cleanly. If their mandibles become worn, the herbivore is converted into a robust plant defense activator. Our models may therefore help to explain why numerous plants produce abrasives which can blunt herbivore mouthparts. Finally, if verified, the models we propose may be generalizable for cell to cell transport of water and pathogen-derived regulators.


Asunto(s)
Plantas , Agua , Agua/metabolismo , Plantas/metabolismo , Oxilipinas/metabolismo , Ciclopentanos/metabolismo , Herbivoria
3.
Biol Proced Online ; 22: 5, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32140080

RESUMEN

BACKGROUND: The toxicity and side effects caused by adjuvant chemotherapy (ACT) after radical surgery for lung adenocarcinoma (LAC) lead to early termination frequently. This study was conducted to provide an objective basis for the effect of Chinese herbal medicine formulas (CHMFs) combined with chemotherapy in reducing toxicity and enhancing efficacy of ACT. METHOD: From February 17th, 2012 to March 20th, 2015, 233 patients from 7 hospitals diagnosed with LAC in IB~IIIA stage were randomly assigned into ACT + CHMF group (116 patients) and ACT + placebo group (117 patients). CHMF was taken orally until the end of chemotherapy. Chemotherapy-related toxic, side effects were investigated as the primary outcome. Disease-free survival (DFS) and overall survival (OS) were used as the secondary outcome. RESULTS: At one week following chemotherapy, the incidence of dry mouth, diarrhea and thrombocytopenia significantly decreased in CHMF group (P = 0.017, P = 0.033, P = 0.019, respectively). At two weeks following chemotherapy, fatigue and diarrhea were more obvious in the placebo group (P = 0.028, P = 0.025, respectively). In addition, patients in the CHMF group showed an increase in median DFS from 37.1 to 51.5 months compared with placebo group although there was no statistical significance (P = 0.16). In the stage IB subgroup, the CHMF group had a significantly better DFS (HR (95% CI) = 0.53 (0.28-0.99), P = 0.046). There was no significant difference in OS between the groups (P = 0.72). CONCLUSION: For patients with LAC, ACT combined with CHMF after radical surgery can prolong the DFS time especially in the early stage, and reduces the chemotherapy-related toxic and side effects. TRIAL REGISTRATION: NCT01441752. Registered 14 July, 2011.

4.
Int J Mol Sci ; 20(20)2019 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-31614879

RESUMEN

In the last 2-3 decades, gene therapy represented a promising option for hepatocellular carcinoma (HCC) treatment. However, the design of safe and efficient gene delivery systems is still one of the major challenges that require solutions. In this study, we demonstrate a versatile method for covalent conjugation of glycyrrhizin acid (GL) or glycyrrhetinic acid (GA) to increase the transfection efficiency of Polyethyleneimine (PEI, Mw 1.8K) and improve their targeting abilities of hepatoma carcinoma cells. GA and GL targeting ligands were grafted to PEI via N-acylation, and we systematically investigated their biophysical properties, cytotoxicity, liver targeting and transfection efficiency, and endocytosis pathway trafficking. PEI-GA0.75, PEI-GL10.62 and PEI-GL20.65 conjugates caused significant increases in gene transfection efficiency and superior selectivity for HepG2 cells, with all three conjugates showing specific recognition of HepG2 cells by the free GA competition assay. The endocytosis inhibition and intracellular trafficking results indicated that PEI-GA0.75 and GL10.62 conjugates behaved similarly to SV40 virus, by proceeding via the caveolae- and clathrin-independent mediated endocytosis pathway and bypassing entry into lysosomes, with an energy independent manner, achieving their high transfection efficiencies. In the HepG2 intraperitoneal tumor model, PEI-GA0.75 and PEI-GL10.62 carrying the luciferase reporter gene gained high gene expression, suggesting potential use for in vivo application.


Asunto(s)
Carcinoma Hepatocelular/terapia , Técnicas de Transferencia de Gen , Terapia Genética/métodos , Ácido Glicirretínico/análogos & derivados , Ácido Glicirrínico/análogos & derivados , Neoplasias Hepáticas/terapia , Polietileneimina/análogos & derivados , Animales , Endocitosis , Femenino , Genes Reporteros , Células Hep G2 , Humanos , Ratones , Ratones Endogámicos BALB C , Nanopartículas/química , Nanopartículas/metabolismo
5.
Mol Pharm ; 14(11): 4032-4041, 2017 11 06.
Artículo en Inglés | MEDLINE | ID: mdl-28980818

RESUMEN

Stimuli-responsive nanomedicine with theranostic functionalities with reduced side-effects has attracted growing attention, although there are some major obstacles to overcome before clinical applications. Herein, we present an acid-activatable theranostic unimolecular micelles based on amphiphilic star-like polymeric prodrug to systematically address typical existing issues. This smart polymeric prodrug has a preferable size of about 35 nm and strong micellar stability in aqueous solution, which is beneficial to long-term blood circulation and efficient extravasation from tumoral vessels. Remarkably, the polymeric prodrug has a high drug loading rate up to 53.1 wt%, which induces considerably higher cytotoxicity against tumor cells (HeLa cells and MCF-7 cells) than normal cells (HUVEC cells) suggesting a spontaneous tumor-specific targeting capability. Moreover, the polymeric prodrug can serve as a fluorescent nanoprobe activated by the acidic microenvironment in tumor cells, which can be used as a promising platform for tumor diagnosis. The superior antitumor effect in this in vitro study demonstrates the potential of this prodrug as a promising platform for drug delivery and cancer therapy.


Asunto(s)
Antineoplásicos/química , Polímeros/química , Profármacos/química , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos/métodos , Células HeLa , Células Endoteliales de la Vena Umbilical Humana , Humanos , Células MCF-7 , Micelas
6.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(6): 1966-70, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30053362

RESUMEN

Catalpa sawdust was respectively pretreated by NaOH, Ca(OH)2, H2SO4 and HCl solution, and the enzymatic hydrolysis of catalpa sawdust was significantly enhanced by alkaline pretreatments. In order to investigate the mechanisms of pretreatment of catalpa sawdust, the characteristics of catalpa sawdust before and after pretreatments were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. It was found that the surface of catalpa sawdust was disrupted by four kinds of chemical pretreatment, and the pretreatment with Ca(OH)2 solution resulted in the most serious damage. The XRD results showed that part of amorphous regions was damaged by alkaline pretreatments, which led to a relative increase of crystallinity Index (CrI) of catalpa sawdust; while the CrI of catalpa sawdust was insignificantly influenced by acid pretreatments. The FTIR analysis displayed that the molecular structures of hemicellulose and lignin of catalpa sawdust were damaged in different degrees by four types of pretreatment. The significant improvement of enzymatic hydrolysis of catalpa sawdust after alkaline pretreatment might be attributed to the effective delignification of alkaline.


Asunto(s)
Celulosa/química , Espectroscopía Infrarroja por Transformada de Fourier , Hidrólisis , Lignina , Microscopía Electrónica de Rastreo , Polisacáridos , Madera , Difracción de Rayos X
7.
Biochem J ; 461(3): 497-508, 2014 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-24814218

RESUMEN

Lantibiotics are ribosomally synthesized antimicrobial peptides containing unusual amino acids. As promising alternatives to conventional antibiotics, they have a high potential for alleviating the problem of emergent antibiotic resistance, with possible applications in many industries that have antibacterial demand. Bovicin HJ50 is a type AII lantibiotic, the largest group of lantibiotics, comprising a linear N-terminal region and a globular C-terminal region. Interestingly, bovicin H50 has a disulfide bond that is rare in this group. Owing to limited information about the spatial structures of type AII lantibiotics, the functional regions of this type and the role of the disulfide bond are still unknown. In the present study, we resolved the solution structure of bovicin HJ50 using NMR spectroscopy. This is the first spatial structure of a type AII lantibiotic. Bovicin HJ50 exhibited high flexibility in aqueous solution, whereas varied rigidities were observed in the different rings with the conserved ring A being the most rigid. The charged residues Lys¹¹, Asp¹² and Lys³°, as well as the essential disulfide bond were critical for antimicrobial activity. Importantly, bovicin HJ50 showed not only peptidoglycan precursor lipid II-binding ability, but also pore-forming activity, which is significantly different from other bacteriostatic type AII lantibiotics, suggesting a novel antimicrobial mechanism.


Asunto(s)
Antibacterianos/farmacología , Bacteriocinas/farmacología , Modelos Moleculares , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Antibacterianos/química , Ácido Aspártico/química , Bacteriocinas/química , Bacteriocinas/genética , Membrana Celular/química , Membrana Celular/efectos de los fármacos , Secuencia Conservada , Cistina/química , Enterococcus/química , Enterococcus/efectos de los fármacos , Enterococcus/crecimiento & desarrollo , Liposomas/química , Liposomas/metabolismo , Lisina/química , Potenciales de la Membrana/efectos de los fármacos , Micrococcus luteus/química , Micrococcus luteus/efectos de los fármacos , Micrococcus luteus/crecimiento & desarrollo , Datos de Secuencia Molecular , Proteínas Mutantes/química , Proteínas Mutantes/farmacología , Conformación Proteica , Precursores de Proteínas/química , Precursores de Proteínas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacología , Alineación de Secuencia , Solubilidad , Relación Estructura-Actividad , Propiedades de Superficie/efectos de los fármacos
8.
J Biomater Sci Polym Ed ; 35(8): 1157-1176, 2024 06.
Artículo en Inglés | MEDLINE | ID: mdl-38386369

RESUMEN

Nitric oxide (NO) plays an important role as a signalling molecule in the biological system. Organoselenium-coated or grafted biomaterials have the potential to achieve controlled NO release as they can catalyse decomposition of endogenous S-nitrosothiols to NO. However, such biomaterials are often challenged by the loss of the catalytic sites, which can affect the stability in tissue repair applications. In this work, we prepare a diselenide-containing poly(ester urethane)urea (SePEUU) polymer with Se-Se in the backbone, which is further electrospun into fibrous membranes by blending with poly(ester urethane)urea (PEUU) without diselenide bonds. The presence of catalytic sites in the main chain demonstrates stable and long-lasting NO catalytic activity, while the porous structure of the fibrous membranes ensures uniform distribution of the catalytic sites and better contact with the donor-containing solution. PEUU/SePEUU50 in 50/50 mass ratio has a physiologically adapted rate of NO release, with a sustained generation of NO after exposure to PBS at 37 °C for 30 d. PEUU/SePEUU50 has a low hemolysis and protein adsorption, with mechanical properties in the wet state matching those of natural vascular tissues. It can promote the adhesion and proliferation of human umbilical vein endothelial cells in vitro and control the proliferation of vascular smooth muscle cells in the presence of NO generation. This study exhibits the electrospun fibrous membranes have potential for utilizing as hemocompatible biomaterials for regeneration of blood-contacting tissues.


Asunto(s)
Materiales Biocompatibles , Óxido Nítrico , Poliésteres , Poliuretanos , Óxido Nítrico/química , Óxido Nítrico/metabolismo , Humanos , Poliuretanos/química , Poliésteres/química , Catálisis , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Células Endoteliales de la Vena Umbilical Humana , Hemólisis/efectos de los fármacos , Membranas Artificiales , Proliferación Celular/efectos de los fármacos , Adsorción
9.
Int J Biol Macromol ; 275(Pt 1): 133676, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38971134

RESUMEN

Stimuli-responsive antioxidant Pickering emulsions play crucial role in many industrial areas. This study demonstrated for the first time oil-in-water Pickering emulsions with outstanding antioxidation and responsive demulsification stabilized by functionalized cellulose nanocrystals (CNCs). Dialdehyde cellulose nanocrystals (DACs) were first prepared through the oxidation of CNCs with periodate, followed by the grafting of p-aminophenols (PAPs) onto their surfaces through Schiff base reaction, affording PAP grafted DACs (DAC-g-PAP) via dynamic covalent linkage. The degree of the oxidation (DO) of DACs had a significant effect on the yield of the targeting DAC-g-PAP nanoparticles. High DO (≥40 %) potentially led to the degradation of DACs during the grafting of PAP. The introduced PAP endowed DACs with excellent radical scavenging capability, thereby providing antioxidant properties while improving the hydrophobicity. DAC-g-PAP nanoparticles were then applied as Pickering emulsifiers to prepare oil-in-water Pickering emulsions. The resultant Pickering emulsions indicated exceptional antioxidant and pH-responsiveness together with good freezing-thaw stability. The structures of DAC-g-PAP nanoparticles were thoroughly characterized in this study.


Asunto(s)
Antioxidantes , Celulosa , Emulsiones , Nanopartículas , Emulsiones/química , Nanopartículas/química , Celulosa/química , Celulosa/análogos & derivados , Antioxidantes/química , Concentración de Iones de Hidrógeno , Oxidación-Reducción , Interacciones Hidrofóbicas e Hidrofílicas , Agua/química
10.
Bioresour Technol ; 395: 130364, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38262543

RESUMEN

The higher heating value of biochar is an important parameter for the utilization of biomass energy. In this work, extreme gradient boosting regression and artificial neural network were used to predict it based on the characteristics of biomass and pyrolysis conditions. Besides, empirical correlations were developed for comparison. Results showed that the extreme gradient boosting regression models showed better performance (R2 = 0.83-0.94). The shapley additive explanations and partial dependence plot indicated that lignin content and higher heating value of raw material were highly positively correlated with higher heating value of biochar, and found the better conditions such as pyrolysis temperature (>550 °C), lignin content (>40 wt%) for high-higher heating value biochar preparation. What's more, a program that predicted higher heating value of biochar was developed through PySimpleGUI library. It offered a new optimization idea for the directional preparation process of biochar.


Asunto(s)
Lignina , Pirólisis , Biomasa , Calefacción , Carbón Orgánico , Aprendizaje Automático
11.
Acta Biomater ; 164: 553-562, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-37072068

RESUMEN

Precise combination therapy, involving multiple chemotherapeutics with pharmacologically synergistic antitumor effects, is a promising approach to address the challenge of monotherapy with insufficient activity towards their targets of interest. We employed Pt←pyridine coordination-driven assembly to construct a stoichiometric coordination complex of camptothecin and organoplatinum (II) (Pt-CPT). The Pt-CPT complex exhibited a remarkable synergistic effect toward several tumor cell lines, which is equal to the optimal synergistic effect of (PEt3)2Pt(OTf)2 (Pt) and CPT mixture at various ratios. An amphiphilic polymer with H2O2-responsiveness and glutathione (GSH)-depleting ability (PO) was used to encapsulate Pt-CPT complex to enable the nanomedicine (Pt-CPT@PO) with prolonged blood circulation and elevated tumor accumulation. The Pt-CPT@PO nanomedicine exhibited remarkable synergistic antitumor efficacy and antimetastatic effect on a mice orthotopic breast tumor model. This work demonstrated the potential of stoichiometric coordination-driven assembly of organic therapeutics with metal-based drugs in developing advanced nanomedicine with optimal synergistic antitumor activity. STATEMENT OF SIGNIFICANCE: In this study, for the first time, we employed Pt←pyridine coordination-driven assembly to construct a stoichiometric coordination complex of camptothecin and organoplatinum (II) (Pt-CPT), with an optimal synergistic effect at various ratios. Then it was encapsulated into an amphiphilic polymer with H2O2-responsiveness and glutathione (GSH)-depleting ability (PO) to enable the nanomedicine (Pt-CPT@PO) with prolonged blood circulation and elevated tumor accumulation. The Pt-CPT@PO nanomedicine exhibited remarkable synergistic antitumor efficacy and antimetastatic effect on a mice orthotopic breast tumor model.


Asunto(s)
Neoplasias de la Mama , Camptotecina , Ratones , Animales , Humanos , Femenino , Camptotecina/farmacología , Camptotecina/uso terapéutico , Nanomedicina , Peróxido de Hidrógeno , Línea Celular Tumoral , Polímeros , Modelos Animales de Enfermedad , Glutatión , Neoplasias de la Mama/tratamiento farmacológico
12.
J Neuroinflammation ; 9: 136, 2012 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-22721162

RESUMEN

BACKGROUND: Neuropathic pain in the trigeminal system is frequently observed in clinic, but the mechanisms involved are largely unknown. In addition, the function of immune cells and related chemicals in the mechanism of pain has been recognized, whereas few studies have addressed the potential role of chemokines in the trigeminal system in chronic pain. The present study was undertaken to test the hypothesis that chemokine C-C motif ligand 2 (CCL2)-chemokine C-C motif receptor 2 (CCR2) signaling in the trigeminal nucleus is involved in the maintenance of trigeminal neuropathic pain. METHODS: The inferior alveolar nerve and mental nerve transection (IAMNT) was used to induce trigeminal neuropathic pain. The expression of ATF3, CCL2, glial fibrillary acidic protein (GFAP), and CCR2 were detected by immunofluorescence histochemical staining and western blot. The cellular localization of CCL2 and CCR2 were examined by immunofluorescence double staining. The effect of a selective CCR2 antagonist, RS504393 on pain hypersensitivity was checked by behavioral testing. RESULTS: IAMNT induced persistent (>21 days) heat hyperalgesia of the orofacial region and ATF3 expression in the mandibular division of the trigeminal ganglion. Meanwhile, CCL2 expression was increased in the medullary dorsal horn (MDH) from 3 days to 21 days after IAMNT. The induced CCL2 was colocalized with astroglial marker GFAP, but not with neuronal marker NeuN or microglial marker OX-42. Astrocytes activation was also found in the MDH and it started at 3 days, peaked at 10 days and maintained at 21 days after IAMNT. In addition, CCR2 was upregulated by IAMNT in the ipsilateral medulla and lasted for more than 21 days. CCR2 was mainly colocalized with NeuN and few cells were colocalized with GFAP. Finally, intracisternal injection of CCR2 antagonist, RS504393 (1, 10 µg) significantly attenuated IAMNT-induced heat hyperalgesia. CONCLUSION: The data suggest that CCL2-CCR2 signaling may be involved in the maintenance of orofacial neuropathic pain via astroglial-neuronal interaction. Targeting CCL2-CCR2 signaling may be a potentially important new treatment strategy for trigeminal neuralgia.


Asunto(s)
Quimiocina CCL2/fisiología , Neuralgia/metabolismo , Células del Asta Posterior/metabolismo , Receptores CCR2/fisiología , Neuralgia del Trigémino/metabolismo , Animales , Masculino , Ratones , Neuralgia/inmunología , Neuralgia/patología , Células del Asta Posterior/patología , Transducción de Señal/inmunología , Neuralgia del Trigémino/inmunología , Neuralgia del Trigémino/patología
13.
Cells ; 11(24)2022 12 12.
Artículo en Inglés | MEDLINE | ID: mdl-36552780

RESUMEN

Foot-and-mouth disease virus (FMDV) poses a significant threat to the livestock industry. Through their recognition of the conserved epitopes presented by the swine leukocyte antigen (SLA), T cells play a pivotal role in the antiviral immunity of pigs. Herein, based on the peptide binding motif of SLA-2*HB01, from an original SLA-2 allele, a series of functional T-cell epitopes derived from the dominant antigen VP1 of FMDV with high binding capacity to SLA-2 were identified. Two parallel peptides, Hu64 and As64, from the O and Asia I serotypes, respectively, were both crystallized with SLA-2*HB01. Compared to SLA-1 and SLA-3, the SLA-2 structures showed the flexibility of residues in the P4, P6, and P8 positions and in their potential interface with TCR. Notably, the peptides Hu64 and As64 adopted quite similar overall conformation when bound to SLA-2*HB01. Hu64 has two different conformations, a more stable 'chair' conformation and an unstable 'boat' conformation observed in the two molecules of one asymmetric unit, whereas only a single 'chair' conformation was observed for As64. Both Hu64 and As64 could induce similar dominant T-cell activities. Our interdisciplinary study establishes a basis for the in-depth interpretation of the peptide presentation of SLA-I, which can be used toward the development of universal vaccines.


Asunto(s)
Virus de la Fiebre Aftosa , Porcinos , Animales , Serogrupo , Epítopos de Linfocito T , Péptidos
14.
J Nanosci Nanotechnol ; 11(2): 1217-24, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21456162

RESUMEN

Theophylline imprinted polymers were synthesized on the surface of multiwalled carbon nanotubes via atom transfer radical polymerization using brominated multiwalled carbon nanotubes as an initiator. The nanotube-based initiator was prepared by directly reacting acyl chloride-modified multiwalled carbon nanotubes with 2-hydroxylethyl-2'-bromoisobutyrate. The grafting copolymerization of 2-hydroxyethyl-2-methyl-2-propenoate and ethylene glycol dimethacrylate in the presence of template theophylline led to thin molecularly imprinted polymer films coating multiwalled carbon nanotubes. The thickness of molecularly imprinted polymer films prepared in this study was about 5 nm as determined by transmission electron microscopy. Fourier-transform infrared spectroscopy was utilized to follow the introduction of initiator groups as well as polymers on the carbon nanotube surfaces. Thermogravimetric analysis indicated that the molecularly imprinted polymers were successfully grown from the carbon nanotube surfaces, with the final products having a polymer weight percentage of ca. 50 wt%. The adsorption properties, such as adsorption dynamics, special binding and selective recognition capacity, of the as-prepared molecularly imprinted polymer films were evaluated. The results demonstrated that the composite of molecularly imprinted polymers and multiwalled carbon nanotubes not only possessed a rapid dynamics but also exhibited a good selectivity toward theophylline, compared to caffeine.


Asunto(s)
Impresión Molecular/métodos , Nanotubos de Carbono/química , Teofilina/química , Adsorción , Cafeína/química , Microscopía Electrónica de Transmisión , Nanotecnología , Nanotubos de Carbono/ultraestructura , Polímeros/química , Espectroscopía Infrarroja por Transformada de Fourier
15.
PLoS One ; 16(10): e0258159, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34597329

RESUMEN

Wood-inhabiting fungi are crucial to wood decay and decomposition in S. psammophila sand barriers, which in turn consumingly influence nutrient dynamics in desert soils. In the case of an extremely arid desert, as opposed to forests, little of known about the fungal community composition of decaying wood and the effects of decomposing wood on soil physical and chemical properties. Combined with high-throughput gene sequencing technology, we investigated the relationships between microenvironment factors with fungal community composition and diversity during the decomposition of Salix psammophila sand barriers. The results showed that the destruction of lignocellulose components during the decay process of S. psammophila sand barrier alters the physical and chemical properties of the surrounding soil. Compared with one-year sand barrier, lignin and cellulose of seven-year S. psammophila sand barrier decreased by 40.48% and 38.33%, respectively. Soil available potassium and available nitrogen increased by 39.80% and 99.46%, respectively. We confirmed that soil available nitrogen, soil pH and soil moisture content significantly affected the fungal community distribution of S. psammophila sand barriers. Sordariomycetes are mainly affected by the positive correlation of soil pH, while Eurotiomycetes are most affected by the positive correlation of soil moisture content and soil porosity. Although our results highlighted the importance of bidirectional interactions between fungi in decayed sand barriers and soil properties, their contribution to the desert ecosystem still needs further confirmation from future studies. However, overall our findings improved the current understanding of the sand barrier-soil interactions on the process of ecological restoration.


Asunto(s)
Salix/química , Microbiología del Suelo , Suelo/química , Madera/química , Celulosa/química , Clima Desértico , Lignina/química , Micobioma , Salix/metabolismo
16.
Bioresour Technol ; 341: 125815, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34454234

RESUMEN

To solve the central problems caused by traditional composting treatments, such as long-time consumption and poor regulation effects, this study used three fermentation methods and four enzymes to develop rapid and directional regulation methods to convert wheat straw into a suitable substrate. The results showed that the mixed anaerobic method led to better pH (4.39-5.75) and EC values (1.27-1.89 mS/cm) in the straw substrates, while the aerobic method retained more nutrients and increased lignin and cellulose contents by 5.07-8.04% and 1.52-3.32%. The cellulase mixed with hemicellulase or laccase treatments all increased the crystallinity by 0.45-7.23%. The TG/DTG results showed that all treatments decreased the initial straw glass transition temperature, particularly when using the mixed anaerobic method, with decreases of 10.63-25.48 °C. Overall, mixed anaerobic fermentation and multiple enzymes, including cellulase, have been suggested as alternative biological modification methods for straw substrates.


Asunto(s)
Celulasa , Triticum , Celulasa/metabolismo , Fermentación , Lignina/metabolismo , Suelo , Triticum/metabolismo
17.
World J Clin Cases ; 9(32): 9762-9769, 2021 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-34877315

RESUMEN

BACKGROUND: Routine preclinical interventions for patients with chronic periodontitis such as supragingival cleaning and subgingival curettage, establishing a balanced occlusal relationship, and irrigation with 3% hydrogen peroxide can relieve the symptoms to some extent. However, there is room for improvement in the overall effect. For example, Er:YAG lasers can quickly increase the temperature of the irradiated tissue, effectively eliminate dental plaque and calculus, reduce periodontal pockets, adjust periodontal microecology, and reduce the gingival sulcus. The content of factors in the liquid, and then achieve the purpose of treatment. AIM: The aim was evaluate the effect of Er:YAG laser-assisted routine therapy on the periodontal status in chronic periodontitis. METHODS: Between October 2018 and January 2020, 106 patients with chronic periodontitis in our hospital were randomly assigned to either the study or control group, with 53 patients in each group. The control group underwent routine therapy, and the study group underwent Er:YAG laser therapy in addition to routine therapy. We evaluated the treatment outcome in both groups. Periodontal status was determined by clinical attachment loss (CAL), gingival index (GI), periodontal probing depth (PD), dental plaque index (PLI), and sulcular bleeding index (SBI), inflammatory factors in the gingival crevicular fluid, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8], and colony forming units (CFUs). RESULTS: Total effectiveness in the study group (94.34%) was higher than that in the control group (79.25%, P < 0.05). The clinical parameters in the study group (PD, 5.28 ± 1.08 mm; CAL, 4.81 ± 0.79 mm; SBI, 3.37 ± 0.59; GI, 1.38 ± 0.40; PLI, 2.05 ± 0.65) were not significantly different from those in the control group (PD, 5.51 ± 1.14 mm; CAL, 5.09 ± 0.83 mm; SBI, 3.51 ± 0.62; GI, (1.41 ± 0.37; PLI, 1.98 ± 0.70) before treatment (P > 0.05). However, after treatment, the parameters in the study group (PD, 2.97 ± 0.38 mm; CAL, 2.71 ± 0.64 mm; SBI, 2.07 ± 0.32; GI, 0.51 ± 0.11; PLI, 1.29 ± 0.34) were lower than those in the control group (PD, 3.71 ± 0.42 mm; CAL, 3.60 ± 0.71 mm; SBI, 2.80 ± 0.44; GI, 0.78 ± 0.23; PLI, 1.70 ± 0.51) (P < 0.05). Differences in crevicular TNF-α, IL-6, and IL-8 levels in the study (TNF-α, 7.82 ± 3.43 ng/mL; IL-6, 11.67 ± 2.59 ng/mL; IL-8, 12.12 ± 3.19 pg/mL) and control groups (TNF-α, 9.06 ± 3.89 ng/ml, IL-6, 12.13 ± 2.97 ng/mL, IL-8, 10.99 ± 3.30 pg/mL) before therapy (P > 0.05) were not significant. Following treatment, the parameters were significantly lower in the study group (TNF-α, 2.04 ± 0.89 ng/mL; IL-6, 4.60 ± 1.26 ng/mL; IL-8, 3.15 ± 1.08 pg/mL) than in the control group (TNF-α, 3.11 ± 1.07 ng/mL; IL-6, 6.25 ± 1.41 ng/mL; IL-8, 4.64 ± 1.23 pg/mL, P < 0.05). The difference in the CFU of the study group [(367.91 ± 74.32) × 104/mL and control group (371.09 ± 80.25) × 104/mL] before therapy was not significant (P > 0.05). The CFU decreased in both groups following therapy, however, the CFU values were lower in the study group [(36.09 ± 15.26) × 104/mL] than in the control group [(45.89 ± 18.08) ×104/mL] (P < 0.05). CONCLUSION: Combining Er:YAG lasers with routine measures significantly improved the overall periodontal therapy outcomes by improving periodontal status and reducing oral levels of inflammatory factors and CFUs.

18.
Sci Total Environ ; 790: 148089, 2021 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-34098276

RESUMEN

The extensive use of nonrenewable peat does not meet the strategic goals of sustainable development. This study explores the advantages and disadvantages of using lignocellulose-based agricultural and forestry wastes as peat substitute in substrates for soilless cultivation; further, it also investigates the key factors influencing the physical and chemical properties of the substrates. Accordingly, the physical and chemical properties of four gramineous crop straws and two woody forestry wastes were determined and compared with those of peat and coconut bran. In addition, cellulose, hemicellulose, and lignin were extracted from wheat straw and pine sawdust, and their basic characteristics and structures were compared and analyzed. The results showed that the influence of particle size on the physical properties of substrates was significantly higher (P < 0.01) than the influence of the substrate type, especially with respect to the water-holding and aeration porosities, which had effect sizes (Eta2) of 73.8% and 68.2%, respectively. The electrical conductivity values of the four straws (1.87-3.42 mS/cm) were higher than those of peat and coconut bran (0.50-0.96 mS/cm), which was mainly due to the high hemicellulose contents (28.52%-30.10%) and total nutrient contents (28.46-47.81 g/kg) of the straws. In contrast, the electrical conductivity values of the woody waste substrates were lower (0.28-0.33 mS/cm) than those of peat and coconut bran. Peat and coconut bran contained the lowest cellulose (17.84%-20.95%) and hemicellulose contents (5.14%-7.19%) of all substrates, resulting in a low degradability and good stability. The crystallinity of coconut bran (23.06%) was significantly lower than that of all other substrates (30.36%-43.03%), which mainly contributed to the superior compressibility of coconut bran. The best pretreatment method for biomass waste used as a substrate should be selected according to the target properties of the corresponding components.


Asunto(s)
Lignina , Suelo , Biomasa , Madera
19.
Shanghai Kou Qiang Yi Xue ; 29(3): 262-266, 2020 Jun.
Artículo en Zh | MEDLINE | ID: mdl-33043342

RESUMEN

PURPOSE: To observe and compare the stress distribution of implant, crown, abutment and surrounding bone tissues in the aesthetic zone after restoration of resin-ceramic composite single crown, and provide theoretical basis for clinical restoration. METHODS: Three-dimensional finite element models of alveolar bone, implant, crown, and the thickness of different adhesives between crown and abutment (0.05 mm and 0.1 mm) were established by using Mimics 17.0 software.Force was applied at the angle of 130° with the long axis of the implant, the loading position was 2 mm from the incisal cingulum, and other force on the incisal margin was loaded in parallel to the long axis of the implant. The size was 100 N. Linear static stress analysis was carried out to compare the Von Mises stress after single crown restoration with different materials. RESULTS: When the thickness of adhesive was 0.05 mm, and resin cement was selected, after restoration of Enamic, Ultimate resin ceramic composite crown, the peak stress of alveolar bone, implant, crown and abutment was more uniform and decreased slightly, but the difference was not significant compared with that of IPS Empress, blocs Mark Ⅱ ceramic crown. When the thickness of adhesive was 0.05 mm, the peak stress was significantly lower than that of 0.1 mm. There was no significant difference in the stress between glass ionomer cement and resin cement.Under the same conditions, restoration with Ultimate crown had smaller stress value of peak Von Mises. CONCLUSIONS: The stress of resin composite ceramics single crown when applied to implantation in aesthetic area is slightly less and more uniform. The proportion of resin in composites and the thickness of adhesive can affect the stress distribution and peak value.


Asunto(s)
Implantes Dentales , Cerámica , Coronas , Análisis del Estrés Dental , Estética Dental , Análisis de Elementos Finitos
20.
J Mater Chem B ; 8(32): 7121-7134, 2020 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-32648878

RESUMEN

The Prussian blue (PB) based nanostructure is a mixed-valence coordination network with excellent biosafety, remarkable photothermal effect and multiple enzyme-mimicking behaviours. Compared with other nanomaterials, PB-based nanoparticles (NPs) exhibit several unparalleled advantages in biomedical applications. This review begins with the chemical composition and physicochemical properties of PB-based NPs. The tuning strategies of PB-based NPs and their biomedical properties are systemically demonstrated. Afterwards, the biomedical applications of PB-based NPs are comprehensively recounted, mainly focusing on treatment of tumors, bacterial infection and inflammatory diseases. Finally, the challenges and future prospects of PB-based NPs and their application in disease treatment are discussed.


Asunto(s)
Antibacterianos/química , Antiinflamatorios/química , Antineoplásicos/química , Materiales Biocompatibles/química , Ferrocianuros/química , Nanopartículas del Metal/química , Animales , Antibacterianos/farmacología , Antiinflamatorios/farmacología , Antineoplásicos/farmacología , Materiales Biocompatibles/farmacología , Ferrocianuros/farmacología , Humanos , Imagen por Resonancia Magnética , Imagen Multimodal , Nanocompuestos/química , Imagen Óptica , Fototerapia , Polilisina/química , Polivinilos/química , Porosidad , Pirrolidinas/química , Nanomedicina Teranóstica
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