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Solar-driven CO2 reduction to yield high-value chemicals presents an appealing avenue for combating climate change, yet achieving selective production of specific products remains a significant challenge. We showcase two osmium complexes, przpOs, and trzpOs, as CO2 reduction catalysts for selective CO2-to-methane conversion. Kinetically, the przpOs and trzpOs exhibit high CO2 reduction catalytic rate constants of 0.544 and 6.41 s-1, respectively. Under AM1.5 G irradiation, the optimal Si/TiO2/trzpOs have CH4 as the main product and >90% Faradaic efficiency, reaching -14.11 mA cm-2 photocurrent density at 0.0 VRHE. Density functional theory calculations reveal that the N atoms on the bipyrazole and triazole ligands effectively stabilize the CO2-adduct intermediates, which tend to be further hydrogenated to produce CH4, leading to their ultrahigh CO2-to-CH4 selectivity. These results are comparable to cutting-edge Si-based photocathodes for CO2 reduction, revealing a vast research potential in employing molecular catalysts for the photoelectrochemical conversion of CO2 to methane.
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Deep-blue multi-resonance (MR) emitters with stable and narrow full-width-at-half-maximum (FWHM) are of great importance for widening the color gamut of organic light-emitting diodes (OLEDs). However, most planar MR emitters are vulnerable to intermolecular interactions from both the host and guest, causing spectral broadening and exciton quenching in thin films. Their emission in the solid state is environmentally sensitive, and the color purity is often inferior to that in solutions. Herein, a molecular design strategy is presented that simultaneously narrows the FWHM and suppresses intermolecular interactions by combining intramolecular locking and peripheral shielding within a carbonyl/nitrogen-based MR core. Intramolecularly locking carbonyl/nitrogen-based bears narrower emission of 2,10-dimethyl-12,12-diphenyl-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-4,8(12H)-dione in solution and further with peripheral-shielding groups, deep-blue emitter (12,12-diphenyl-2,10-bis(9-phenyl-9H-fluoren-9-yl)-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-4,8(12H)-dione, DPQAO-F) exhibits ultra-pure emission with narrow FWHM (c.a., 24 nm) with minimal variations (∆FWHM ≤ 3 nm) from solution to thin films over a wide doping range. An OLED based on DPQAO-F presents a maximum external quantum efficiency (EQEmax) of 19.9% and color index of (0.134, 0.118). Furthermore, the hyper-device of DPQAO-F exhibits a record-high EQEmax of 32.7% in the deep-blue region, representing the first example of carbonyl/nitrogen-based OLED that can concurrently achieve narrow bandwidth in the deep-blue region and a high electroluminescent efficiency surpassing 30%.
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Tuberous sclerosis complex (TSC) and focal cortical dysplasia (FCD) type IIb are the predominant causes of drug-refractory epilepsy in children. Dysmorphic neurons (DNs), giant cells (GCs), and balloon cells (BCs) are the most typical pathogenic profiles in cortical lesions of TSC and FCD IIb patients. However, mechanisms underlying the pathological processes of TSC and FCD IIb remain obscure. The Plexin-B2-Sema4C signalling pathway plays critical roles in neuronal morphogenesis and corticogenesis during the development of the central nervous system. However, the role of the Plexin-B2 system in the pathogenic process of TSC and FCD IIb has not been identified. In the present study, we investigated the expression and cell distribution characteristics of Plexin-B2 and Sema4C in TSC and FCD IIb lesions with molecular technologies. Our results showed that the mRNA and protein levels of Plexin-B2 expression were significantly increased both in TSC and FCD IIb lesions versus that in the control cortex. Notably, Plexin-B2 was also predominantly observed in GCs in TSC epileptic lesions and BCs in FCD IIb lesions. In contrast, the expression of Sema4C, the ligand of Plexin-B2, was significantly decreased in DNs, GCs, and BCs in TSC and FCD IIb epileptic lesions. Additionally, Plexin-B2 and Sema4C were expressed in astrocytes and microglia cells in TSC and FCD IIb lesions. Furthermore, the expression of Plexin-B2 was positively correlated with seizure frequency in TSC and FCD IIb patients. In conclusion, our results showed the Plexin-B2-Sema4C system was abnormally expressed in cortical lesions of TSC and FCD IIb patients, signifying that the Plexin-B2-Sema4C system may play a role in the pathogenic development of TSC and FCD IIb.
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Displasia Cortical Focal , Malformaciones del Desarrollo Cortical de Grupo I , Proteínas del Tejido Nervioso , Semaforinas , Esclerosis Tuberosa , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Epilepsia Refractaria/metabolismo , Epilepsia Refractaria/patología , Epilepsia , Displasia Cortical Focal/metabolismo , Displasia Cortical Focal/patología , Células Gigantes/metabolismo , Células Gigantes/patología , Malformaciones del Desarrollo Cortical de Grupo I/metabolismo , Malformaciones del Desarrollo Cortical de Grupo I/patología , Proteínas del Tejido Nervioso/metabolismo , Proteínas del Tejido Nervioso/biosíntesis , Neuronas/metabolismo , Neuronas/patología , Semaforinas/metabolismo , Semaforinas/genética , Semaforinas/biosíntesis , Esclerosis Tuberosa/metabolismo , Esclerosis Tuberosa/patologíaRESUMEN
Objective: This study explored the relationship between college students' physical activity motivation and exercise behavior and constructed a chain mediation model through the mediating roles of exercise climate and exercise self-efficacy. Methods: By random sampling, 1,032 college students were investigated using the Exercise Motivation Scale, Physical Exercise Rating Scale, Exercise Climate Scale, and Exercise Self-Efficacy Scale. Results: (1) There was a huge positive correlation between exercise motivation and exercise behavior (r = 0.240, p < 0.01), and the immediate ways of linking exercise motivation to exercise behavior were critical (ß = 0.068, t = 0.040, p < 0.01). (2) Exercise motivation could positively predict exercise climate (ß = 0.373, t = 0.061, p < 0.01) and exercise self-efficacy (ß = 0.174, t = 0.039, p < 0.01), and exercise climate could emphatically foresee exercise behavior (ß = 0.302, t = 0.051, p < 0.01). Exercise self-efficacy could foresee exercise behavior decidedly (ß = 0.190, t = 0.048, p < 0.01). (3) Exercise climate and exercise self-efficacy play a critical intervening role between exercise motivation and exercise behavior. The intercession impact is explicitly made out of aberrant impacts created in three ways: exercise motivation â exercise climate â exercise behavior (mediating effect value: 0.113); exercise motivation â exercise self-efficacy â exercise behavior (mediating effect value: 0.033); exercise motivation â exercise climate â exercise self-efficacy â exercise behavior (mediating effect value: 0.027). Conclusion: (1) Exercise climate, exercise self-efficacy, and exercise behavior can all be significantly predicted by exercise motivation, suggesting that exercise motivation may help to enhance these variables. (2) In addition to having a direct impact on exercise behavior, exercise motivation can also have an indirect impact through the separate mediating effects of exercise climate and exercise self-efficacy as well as the chain mediating effect of exercise climate and exercise self-efficacy, which is crucial for encouraging college students to engage in physical activity.
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In the current work, the effects of steam and boiling water blanching on the drying characteristics, water distribution, microstructure, and contents of bioactive substances of Gastrodia elata (G. elata) were explored. Results showed that the degree of steaming and blanching was related to the core temperature of G. elata. The steaming and blanching pretreatment increased the drying time of the samples by more than 50%. The low-field nuclear magnetic resonance (LF-NMR) of treated samples showed that the relaxation time corresponded to water molecule states (bound, immobilized, and free) and G. elata became shorter, which indicated a reduction in free moisture and increased resistance of water diffusion in the solid structure during drying. Hydrolysis of polysaccharides and gelatinization of starch granules was observed in the microstructure of treated samples, which was consistent with changes in water status and drying rates. Steaming and blanching increased gastrodin and crude polysaccharide contents and decreased p-hydroxybenzyl alcohol content. These findings will contribute to a better understanding of the effect of steaming and blanching on the drying behavior and quality attributes of G. elata.
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Deep learning-based object counting models have recently been considered preferable choices for plant counting. However, the performance of these data-driven methods would probably deteriorate when a discrepancy exists between the training and testing data. Such a discrepancy is also known as the domain gap. One way to mitigate the performance drop is to use unlabeled data sampled from the testing environment to correct the model behavior. This problem setting is also called unsupervised domain adaptation (UDA). Despite UDA has been a long-standing topic in machine learning society, UDA methods are less studied for plant counting. In this paper, we first evaluate some frequently-used UDA methods on the plant counting task, including feature-level and image-level methods. By analyzing the failure patterns of these methods, we propose a novel background-aware domain adaptation (BADA) module to address the drawbacks. We show that BADA can easily fit into object counting models to improve the cross-domain plant counting performance, especially on background areas. Benefiting from learning where to count, background counting errors are reduced. We also show that BADA can work with adversarial training strategies to further enhance the robustness of counting models against the domain gap. We evaluated our method on 7 different domain adaptation settings, including different camera views, cultivars, locations, and image acquisition devices. Results demonstrate that our method achieved the lowest Mean Absolute Error on 6 out of the 7 settings. The usefulness of BADA is also supported by controlled ablation studies and visualizations.
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Complex diseases are caused by a variety of factors, and their diagnosis, treatment and prognosis are usually difficult. Proteins play an indispensable role in living organisms and perform specific biological functions by interacting with other proteins or biomolecules, their dysfunction may lead to diseases, it is a natural way to mine disease-related biomarkers from protein-protein interaction network. AUC, the area under the receiver operating characteristics (ROC) curve, is regarded as a gold standard to evaluate the effectiveness of a binary classifier, which measures the classification ability of an algorithm under arbitrary distribution or any misclassification cost. In this study, we have proposed a network-based multi-biomarker identification method by AUC optimization (NetAUC), which integrates gene expression and the network information to identify biomarkers for the complex disease analysis. The main purpose is to optimize two objectives simultaneously: maximizing AUC and minimizing the number of selected features. We have applied NetAUC to two types of disease analysis: 1) prognosis of breast cancer, 2) classification of similar diseases. The results show that NetAUC can identify a small panel of disease-related biomarkers which have the powerful classification ability and the functional interpretability.
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Algoritmos , Neoplasias de la Mama , Área Bajo la Curva , Biomarcadores , Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/genética , Femenino , Humanos , Curva ROCRESUMEN
The myodural bridge (MDB) connects the suboccipital musculature to the spinal dura mater (SDM) as it passed through the posterior atlanto-occipital and the atlanto-axial interspaces. Although the actual function of the MDB is not understood at this time, it has recently been proposed that head movement may assist in powering the movement of cerebrospinal fluid (CSF) via muscular tension transmitted to the SDM via the MDB. But there is little information about it. The present study utilized dogs as the experimental model to explore the MDB's effects on the CSF pressure (CSFP) during stimulated contractions of the suboccipital muscles as well as during manipulated movements of the atlanto-occiptal and atlanto-axial joints. The morphology of MDB was investigated by gross anatomic dissection and by histological observation utilizing both light microscopy and scanning electron microscopy. Additionally biomechanical tensile strength tests were conducted. Functionally, the CSFP was analyzed during passive head movements and electrical stimulation of the suboccipital muscles, respectively. The MDB was observed passing through both the dorsal atlanto-occipital and the atlanto-axial interspaces of the canine and consisted of collagenous fibers. The tensile strength of the collagenous fibers passing through the dorsal atlanto-occipital and atlanto-axial interspaces were 0.16 ± 0.04 MPa and 0.82 ± 0.57 MPa, respectively. Passive head movement, including lateral flexion, rotation, as well as flexion-extension, all significantly increased CSFP. Furthermore, the CSFP was significantly raised from 12.41 ± 4.58 to 13.45 ± 5.16 mmHg when the obliques capitis inferior (OCI) muscles of the examined specimens were electrically stimulated. This stimulatory effect was completely eliminated by severing the myodural bridge attachments to the OCI muscle. Head movements appeared to be an important factor affecting CSF pressure, with the MDB of the suboccipital muscles playing a key role this process. The present study provides direct evidence to support the hypothesis that the MDB may be a previously unappreciated significant power source (pump) for CSF circulation.
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Vértebras Cervicales , Músculos del Cuello , Animales , Articulación Atlantooccipital , Fenómenos Biomecánicos , Perros , Microscopía Electrónica de RastreoRESUMEN
Introduction Telehealth intervention has been proposed as an innovative intervention approach to breast cancer patients, but there are still conflicting results in the literature about its effect. Methods PubMed, EMBASE, CENTRAL and China National Knowledge Infrastructure (CNKI) were searched from inception to 3 October 2016 for randomized controlled trials (RCTs) which assessed the effect of telehealth intervention versus usual care in breast cancer patients. No language restrictions were used. Standardized mean difference (SMD) with corresponding 95% confidence interval (95% CI) was pooled when needed. Subgroup and sensitivity analyses were conducted if necessary and feasible. Results Twenty RCTs with a total of 2190 participants were included into this meta-analysis. Compared with usual care, telehealth intervention was associated with higher quality of life (SMD = 0.60, 95% CI 0.18-1.01, p = 0.005) and self-efficacy (SMD = 0.59, 95% CI 0.19-0.98, p = 0.003), with less depression (SMD = -1.29, 95% CI -2.28 to -0.30, p = 0.01), distress (SMD = -0.25, 95% CI -0.40 to -0.10, p = 0.001) and perceived stress (SMD = -0.30, 95% CI, -0.59 to -0.02, p = 0.04). However, anxiety score did not differ significantly between the two groups (SMD = -0.09, 95% CI -0.22 to 0.04, p = 0.17). Discussion Telehealth intervention is superior to usual care in breast cancer patients for improved quality of life, higher self-efficacy and less depression, distress, and perceived stress. However, these results should be recognized cautiously due to between-study heterogeneity, indicating that further well-designed RCTs are warranted.
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Neoplasias de la Mama/psicología , Educación del Paciente como Asunto/métodos , Calidad de Vida/psicología , Telemedicina/métodos , Actividades Cotidianas , Adulto , Neoplasias de la Mama/terapia , China , Depresión/prevención & control , Femenino , Humanos , Salud Mental , Persona de Mediana Edad , AutoeficaciaRESUMEN
AIM: To evaluate changes of proinflammatory cytokines in aqueous humor of patients with acute primary angle-closure (APAC) and age-related cataracts. METHODS: Twenty eyes of 20 APAC patients and 15 eyes of 15 age-related cataract patients were included in this cross-sectional study. Aqueous humor samples were collected prospectively. The levels of 20 proinflammatory cytokines were evaluated in the aqueous humor of the APAC and cataract patients using the multiplex bead immunoassay technique. Clinical data were collected for correlation analysis. RESULTS: Seven of the 20 proinflammatory cytokines included in the magnetic bead panel were detectable in both APAC eyes and cataract eyes: interleukin (IL)-10, IL-12, IL-15, IL-21, IL-6, chemokine (C-C motif) ligand 20, and tumor necrosis factor alpha (TNF-α). IL-27 was only detectable in APAC eyes. Compared with the cataract eyes, the APAC eyes had significantly elevated concentrations of IL-12 (P=0.036), IL-15 (P=0.001), IL-6 (P=0.012), and IL-27 (only detectable in APAC eyes). Age was positively correlated with IL-12 (P=0.022) and IL-6 (P=0.037), and time elapsed between APAC onset and aqueous humor samples collection was positively correlated with IL-15 (P=0.037), IL-27 (P=0.040), and TNF-α (P=0.042). CONCLUSION: Several proinflammatory cytokines including IL-12, IL-15, IL-6 and IL-27, were elevated in the APAC eyes and may be implicated in its pathologic mechanism.
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Neoplasias del Ojo/diagnóstico , Glaucoma/diagnóstico , Adolescente , Adulto , Anciano , Niño , Preescolar , Errores Diagnósticos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Aphids harbor primary endosymbionts, Buchnera aphidicola, in specialized cells within their body cavities. Aphids and Buchnera have strict mutualistic relationships in nutrition exchange. This ancient association has received much attention from researchers who are interested in endosymbiotic evolution. Previous studies have found parallel phylogenetic relationships between non-galling aphids and Buchnera at lower taxonomic levels (genus, species). To understand whether relatively isolated habitats such as galls have effect on the parallel relationships between aphids and Buchnera, the present paper investigated the phylogenetic relationships of gall aphids from Pemphigus and allied genera, which induce pseudo-galls or galls on Populus spp. (poplar) and Buchnera. The molecular phylogenies inferred from three aphid genes (COI, COII and EF-1α) and two Buchnera genes (gnd, 16S rRNA gene) indicated significant congruence between aphids and Buchnera at generic as well as interspecific levels. Interestingly, both aphid and Buchnera phylogenies supported three main clades corresponding to the galling locations of aphids, namely leaf, the joint of leaf blade and petiole, and branch of the host plant. The results suggest phylogenetic conservatism of gall characters, which indicates gall characters are more strongly affected by aphid phylogeny, rather than host plants.
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Áfidos/microbiología , Áfidos/fisiología , Buchnera/fisiología , Evolución Molecular , Simbiosis , Animales , Áfidos/genética , Áfidos/crecimiento & desarrollo , Buchnera/genética , Genes Bacterianos/genética , Genes de Insecto/genética , FilogeniaRESUMEN
The aphid genus Jacksonia Theobald is reported in China for the first time, from Shaanxi, with the description of a new species, Jacksonia gibbera Qiao, Li, Zhang & Su, sp. n., found on an unidentified plant belonging to the Leguminosae/Fabaceae. A key to species of Jacksonia is provided.
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BACKGROUND: Neovascular glaucoma (NVG) is a refractory disease which is difficult to manage. This study aimed at evaluating the efficacy and safety of adjunctive intravitreal bevacizumab (IVB) injection in conjunction with Ahmed glaucoma valve implantation (AGVI) in the management of NVG. METHODS: This was a retrospective study of patients with NVG in whom AGVI was performed between October 2008 and May 2012. The sample was divided into two groups according to the pretreatment: with adjunctive IVB injection (the IVB group, n = 25 eyes) and without adjunctive IVB injection (the control group, n = 28 eyes). The surgical success rate, number of antiglaucoma medications used, best-corrected visual acuity (BCVA), postoperative complications, regression, and recurrence of iris neovascularization (NVI) were analyzed between the groups. RESULTS: The surgical outcomes of the two groups were compared. The complete success rates in the IVB and control groups were 84.0% and 64.3% at 12 months and 80.0% and 53.6% at 18 months, respectively. There was a significant difference between the two groups (P = 0.041). Mean postoperative intraocular pressures, mean number of postoperative antiglaucoma medications, and BCVA were not significant between the two groups. The NVI in 22 (88.0%) eyes had completely regressed within 2 - 8 days after IVB. However, NVI recurred in 10 eyes (40.0%) 2 - 9 months later after IVB. The IVB group had only 1 case (4.0%) of hyphema out of 25 eyes, while there were 8 (28.6%) cases of hyphema out of 28 eyes in the control group (P = 0.026). CONCLUSIONS: This study showed that preoperative IVB injection reduced NVI remarkably, decreased hyphema, and led to higher surgical success rates. Pre-operative IVB injection may be an effective adjunct to AGVI in the management of NVG.
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Inhibidores de la Angiogénesis/administración & dosificación , Anticuerpos Monoclonales Humanizados/administración & dosificación , Implantes de Drenaje de Glaucoma , Glaucoma Neovascular/terapia , Implantación de Prótesis/métodos , Adulto , Anciano , Bevacizumab , Femenino , Implantes de Drenaje de Glaucoma/efectos adversos , Humanos , Presión Intraocular , Inyecciones Intravítreas , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Agudeza VisualRESUMEN
In this paper, various N-trimethyl chitosan (TMC) of different molecular-weights (approximately 100 KD, approximately 200 KD, and approximately 400 KD, respectively) with the approximately degree of quartenization (DQ) of 40% were successfully synthesized. In vitro cytotoxicity of TMC solution showed the dependence of TMC concentration from 20 microg/ml to 500 microg/ml on the relative cell activity. Molecular weight of TMC did not greatly affect the cytotoxicity of TMC against HEK293 and L929 cells. TMC nanoparticles and alginate modified TMC nanoparticles were prepared by the ionic gelation method. Subsequently, we investigated the properties of TMC nanoparticles and alginate modified TMC nanoparticles intending for oral delivery of antigens. Molecular weight of TMC did not affect the loading capacity (LC) and in vitro release behavior of TMC nanoparticles. However, BSA concentration and alginate modification have strongly effect on properties of TMC nanoparticles (particle size; surface charge; loading efficiency and loading capacity). In vitro release behavior indicated that alginate modification could efficiently decrease initial burst release and extend release time in phosphate buffer (PBS, pH 7.4) and acidic solution (0.1 M HCl, pH = 1) at 37 degrees C. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) assay showed that alginate modification could effectively improve the stability of TMC nanoparticles and protect BSA from degradation or hydrolysis in acidic condition for at least 2 h.
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Quitosano/química , Sistemas de Liberación de Medicamentos/métodos , Nanopartículas/química , Vacunas/química , Administración Oral , Alginatos , Animales , Bovinos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Quitosano/administración & dosificación , Quitosano/toxicidad , Electroforesis en Gel de Poliacrilamida , Ácido Glucurónico , Células HEK293 , Ácidos Hexurónicos , Humanos , Concentración de Iones de Hidrógeno , Ensayo de Materiales , Ratones , Microscopía de Fuerza Atómica , Peso Molecular , Nanopartículas/administración & dosificación , Nanopartículas/toxicidad , Tamaño de la Partícula , Albúmina Sérica Bovina/química , Albúmina Sérica Bovina/farmacocinética , Vacunas/administración & dosificaciónRESUMEN
BACKGROUND: Camptothecin (CPT) has recently attracted increasing attention as a promising anticancer agent for a variety of tumors. But the clinical application is largely hampered by its extreme water insolubility and unpredictable side effect. It is essential to establish an efficient and safe protocol for the administration of CPT versus melanoma. METHODS: Camptothecin was encapsulated with N-trimethyl chitosan (CPT-TMC) through microprecipitation and sonication. Its inhibition effect on B16-F10 cell proliferation and induction of apoptosis was evaluated by MTT assay and flow cytometric analysis in vitro. The anti-tumor activity of CPT-TMC was evaluated in C57BL/6 mice bearing B16-F10 melanoma. Tumor volume, tumor weight and survival time were recorded. Assessment of apoptotic cells within tumor tissue was performed by TUNEL assay. Antiangiogenesis and antiproliferation effects of CPT-TMC in vivo were conducted via CD31 and PCNA immunohistochemistry, respectively. RESULTS: CPT-TMC efficiently inhibited B16-F10 cells proliferation and increased apoptosis in vitro. Experiment group showed significant inhibition compared with free CPT-treated group (81.3% vs. 56.9%) in the growth of B16-F10 melanoma xenografts and prolonged the survival time of the treated mice (P < 0.05). Decreased cell proliferation, increased tumor apoptosis as well as a reduction in angiogenesis were observed. CONCLUSIONS: Our data suggest that N-trimethyl chitosan-encapsulated camptothecin is superior to free CPT by overcoming its insolubility and finally raises the potential of its application in melanoma therapy.
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Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Camptotecina/farmacología , Proliferación Celular/efectos de los fármacos , Quitosano/farmacología , Melanoma Experimental/tratamiento farmacológico , Animales , Antineoplásicos Fitogénicos/farmacocinética , Camptotecina/farmacocinética , Línea Celular Tumoral , Quitosano/farmacocinética , Portadores de Fármacos , Femenino , Técnicas para Inmunoenzimas , Ratones , Ratones Endogámicos C57BL , Ratones Desnudos , Solubilidad , Distribución Tisular , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
In this paper, honokiol nanoparticles were prepared by emulsion solvent evaporation method. The prepared honokiol nanoparticles were characterized by particle size distribution, morphology, zeta potential and crystallography. Results showed that the obtained honokiol nanoparticles at size of 33 nm might be amorphous, and could be well dispersed in water. Due to the great dispersibility in water, the obtained honokiol nanoparticles might have great potential in medical field.
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Compuestos de Bifenilo/química , Química Farmacéutica/métodos , Cristalización/métodos , Medicamentos Herbarios Chinos/química , Lignanos/química , Nanomedicina/métodos , Nanoestructuras/química , Nanoestructuras/ultraestructura , Emulsiones/química , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Solventes/químicaRESUMEN
In this work, a new kind of biodegradable pH-sensitive hydrogel was successfully synthesized by UV-initiated free radical polymerization. The obtained hydrogel was characterized by (1)H NMR and FTIR. Swelling behavior in different aqueous media and pH responsivity of the hydrogels were studied in detail as well. With increase in pH from 1.2 to 7.2, swelling ratio of the hydrogel increased. The morphology was observed by scanning electron microscopy, and the hydrolytic degradation behavior was also investigated in this work.
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Hidrogeles/síntesis química , Metacrilatos/síntesis química , Poliésteres/síntesis química , Polietilenglicoles/síntesis química , Hidrogeles/química , Hidrogeles/metabolismo , Concentración de Iones de Hidrógeno , Hidrólisis , Espectroscopía de Resonancia Magnética , Metacrilatos/química , Metacrilatos/metabolismo , Fotoquímica , Poliésteres/química , Poliésteres/metabolismo , Polietilenglicoles/química , Polietilenglicoles/metabolismoRESUMEN
In this article, nano-magnetite particles (ferrofluid, Fe3O4) were prepared by chemical co-deposition method. A series of biodegradable triblock poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) (PCL-PEG-PCL, PCEC) copolymers were synthesized by ring-opening polymerization method from epsilon-caprolactone (epsilon-CL) initiated by poly(ethylene glycol) diol (PEG) using stannous octoate as catalyst. And the magnetic PCEC composite microspheres were prepared by solvent diffusion method. The properties of the ferrofluid, PCEC copolymer, and magnetic PCEC microspheres were studied in detail by SEM, VSM, XRD, Malvern Laser Particle Sizer, 1H-NMR, GPC, and TG/DTG. Effects of macromolecular weight and concentration of polymer, and the time for ultrasound dispersion on properties of magnetic microspheres were also investigated. The obtained magnetic PCEC microspheres might have great potential application in targeted drug delivery system or cell separation.
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Magnetismo , Microesferas , Poliésteres/química , Poliésteres/síntesis química , Polietilenglicoles/química , Polietilenglicoles/síntesis química , Compuestos Férricos/síntesis química , Modelos Biológicos , Peso Molecular , Porosidad , TemperaturaRESUMEN
In this article, a kind of biodegradable poly(epsilon-caprolactone)-Poly(ethylene glycol)-poly(epsilon-caprolactone) (PCL-PEG-PCL, PCEC) copolymer was synthesized by ring-opening polymerization method. The PCEC nanoparticles were prepared at one-step by modified emulsion solvent evaporation method using CTAB as stabilizer. With increase in PCEC concentration, the particle size increased obviously, but zeta potential only increased slightly. The obtained cationic PCEC nanoparticle was employed to condense and adsorb DNA onto its surface. Plasmid GFP (pGFP) was used as model plasmid to evaluate the loading capacity of cationic PCEC nanoparticles in this work. The DNA/nanoparticles weight ratio at 1:16 induced almost neutral zeta potential of DNA-nanoparticles complex. At this time, the size of complex became abnormally large which implied aggregates formed. So DNA-nanoparticles weight ratio should be chosen carefully. The cationic PCEC nanoparticles had the capacity of condensing plasmid DNA into complex when the DNA/nanoparticles weight ratio was lower than 1:8, which was evidenced by gel retardation assay. In vitro release behavior of DNA/nanoparticle complexes was also studied here. The obtained cationic PCEC nanoparticles might have great potential application in DNA delivery.