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OBJECTIVES: To estimate adolescents and children age using stepwise regression and machine learning methods based on the pulp and tooth volumes of the left maxillary central incisor and cuspid on cone beam computed tomography (CBCT) images, and to compare and analyze the estimation results. METHODS: A total of 498 Shanghai Han adolescents and children CBCT images of the oral and maxillofacial regions were collected. The pulp and tooth volumes of the left maxillary central incisor and cuspid were measured and calculated. Three machine learning algorithms (K-nearest neighbor, ridge regression, and decision tree) and stepwise regression were used to establish four age estimation models. The coefficient of determination, mean error, root mean square error, mean square error and mean absolute error were computed and compared. A correlation heatmap was drawn to visualize and the monotonic relationship between parameters was visually analyzed. RESULTS: The K-nearest neighbor model (R2=0.779) and the ridge regression model (R2=0.729) outperformed stepwise regression (R2=0.617), while the decision tree model (R2=0.494) showed poor fitting. The correlation heatmap demonstrated a monotonically negative correlation between age and the parameters including pulp volume, the ratio of pulp volume to hard tissue volume, and the ratio of pulp volume to tooth volume. CONCLUSIONS: Pulp volume and pulp volume proportion are closely related to age. The application of CBCT-based machine learning methods can provide more accurate age estimation results, which lays a foundation for further CBCT-based deep learning dental age estimation research.
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Determinação da Idade pelos Dentes , Tomografia Computadorizada de Feixe Cônico , Polpa Dentária , Aprendizado de Máquina , Humanos , Tomografia Computadorizada de Feixe Cônico/métodos , Adolescente , Criança , Determinação da Idade pelos Dentes/métodos , Polpa Dentária/diagnóstico por imagem , Dente/diagnóstico por imagem , China , Incisivo/diagnóstico por imagem , Incisivo/anatomia & histologia , Feminino , Masculino , AlgoritmosRESUMO
Porous structure design and reversible regulation of pore size during adsorption-desorption are crucial to the removal of pollutants in water such as Cr(VI). In this paper, micropores and switchable mesopores were constructed on MCM-41 to further improve adsorption-desorption performance of Cr(VI) via the confinement effect of micropores and opening and closing of mesopores. 2-Vinylpyridine was introduced and polymerized into the pores and on the pore mouth of MCM41 modified by CâC group (AM41) under the irradiation of ultraviolet light. The obtained samples (PM41) possessed mesopores (2.73 nm) and micropores (1.36 nm), where mesopores could open or close under different pH and micropores showed the confinement effect because their pore size is close to Cr(VI) diameter (0.87 nm). Compared with MCM-41, the introduction of poly(2-vinylpyridine) enhanced obviously its adsorptive ability and it trapped most of the Cr(VI) (99%) in solution, 12 times higher than that of the parent sample. The change of pore size is favorable to the cycle performance, and after 3 times recycling, the removal rate of Cr(VI) by PM41-20 remained above 88%. Langmuir isotherm showed a better data correlation than the Freundlich model. Cr(VI) in solution was removed by electrostatic interaction between the pyridine group and Cr(VI) and the confinement effect from micropores.
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BACKGROUD: It is important to expound the opposite clinical outcomes between children and adulthood for eradicate malaria. There remains unknown about the correlation between adaptive immune response and age-related in malaria. METHODS: 4 and 8-week-old mice were used to mimic children and adulthood, respectively. Parasitemia and the survival rate were monitored. The proportion and function of Th1 and Th2 cells were detected by FACS. The levels of IFN-γ, IL-4, total IgG, IgG1, IgG2a and Plasmodium yoelii MSP-1-specific IgG were measured by ELISA. RESULTS: The adult group showed greater resistance to P. yoelii 17XL infection, with lower parasitemia. Compared with 4-week-old mice, the percentage of CD4+T-bet+IFN-γ+ Th1 cells as well as IFN-γ production were significantly increased on day 5 p.i. in the 8-week-old mice after P. yoelii 17XNL infection. The percentage of CD4+GATA3+IL-4+ Th2 cells and CD4+CXCR5+ Tfh cells, and IL-4 production in the 8-week-old mice significantly increased on day 5 and day 10 after P. yoelii 17XNL infection. Notably, the levels of total IgG, IgG1, IgG2a and P. yoelii MSP-1-specific IgG were also significantly increased in the 8-week-old mice. PD-1, a marker of exhaustion, was up-regulated on CD4+ or activated CD4+ T cells in the 8-week-old mice as compared to the 4-week-old group. CONCLUSIONS: Thus, we consider that enhanced cellular and humoral adaptive immunity might contribute to rapid clearance of malaria among adults, likely in a PD-1-dependent manner due to induction of CD4+ T cells exhaustion in P. yoelii 17XNL infected 8-week-old mice.
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Imunidade Adaptativa/imunologia , Malária/imunologia , Plasmodium yoelii/imunologia , Fatores Etários , Animais , Modelos Animais de Doenças , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Malária/mortalidade , Camundongos , Camundongos Endogâmicos BALB C , Parasitemia/imunologia , Parasitemia/mortalidade , Plasmodium yoelii/classificação , Receptor de Morte Celular Programada 1/metabolismo , Transdução de Sinais , Taxa de Sobrevida , Linfócitos T/citologia , Linfócitos T/metabolismoRESUMO
Long non-coding RNAs (lncRNAs) have been identified as critical regulators in gastric cancer (GC) progression. However, whether lncRNA small nucleolar host gene 4 (SNHG4) functions in GC development remains unknown. In this study, the bio-functional role of SNHG4 and its potential mechanism on GC progression were systematically dissected. To investigate the role of SNHG4 in GC, we silenced SNHG4 using short hairpin RNAs (shRNAs) to perform loss-of-function assays. The results showed that SNHG4 expression in GC cells was at a higher level compared to normal gastric mucosal epithelial cells. Knockdown of SNHG4 dramatically suppressed proliferation, migration and invasion, and blocked cell cycle progression of GC cells. Moreover, knockdown of SNHG4 upregulated microRNA-204-5p (miR-204-5p) expression, whereas downregulated ribonucleotide reductase subunit M2 (RRM2) expression in GC cells. Dual-luciferase reporter assay results showed that miR-204-5p was a direct target of SNHG4. Additionally, knockdown of SNHG4 suppressed GC tumorigenesis in xenograft mouse models. Taken together, these data demonstrated that knockdown of SNHG4 suppressed GC development by targeting miR-204-5p.
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MicroRNAs , RNA Longo não Codificante , Neoplasias Gástricas , Animais , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Camundongos , MicroRNAs/genética , RNA Longo não Codificante/genética , Neoplasias Gástricas/genéticaRESUMO
Rib segment, as one of the most widely used autologous boneresources for bone repair, is commonly isolated with an empty left in the defect. Although defective rib repair is thought to be unnecessary traditionally, it's of vital importance actually to promote rib regeneration for patients with better postoperative recovery and higher life quality. Comparative investigations on rabbit rib bone regeneration with and without graft were reported in this article. A segmental defect was performed on the 8th rib of 4-month-old male New Zealand rabbits. The mineralized collagen bone graft (MC) was implanted into the defect and evaluated for up to 12 weeks. The rib bone repair was investigated by using X-ray at 4, 8 and 12 weeks and histological examinations at 12 weeks after surgery, which showed a higher bone remodeling activity in the groups with MC implantation in comparison with blank control group, especially at the early stage of remodeling.
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Regeneração Óssea , Transplante Ósseo/métodos , Costelas/cirurgia , Animais , Remodelação Óssea , Substitutos Ósseos , Calcificação Fisiológica , Colágeno , Masculino , Coelhos , Costelas/lesões , Alicerces Teciduais , CicatrizaçãoRESUMO
In a new strategy for loading drugs into mesoporous silica, a hydrophilic (heparin) or hydrophobic drug (ibuprofen) is encapsulated directly in a one-pot synthesis by evaporation-induced self-assembly. In situ drug loading significantly cuts down the preparation time and dramatically increases the loaded amount and released fraction of the drug, and appropriate drug additives favor a mesoporous structure of the vessels. Drug loading was verified by FTIR spectroscopy and release tests, which revealed much longer release with a larger amount of heparin or ibuprofen compared to postloaded SBA-15. Besides, the in vitro anticoagulation properties of the released heparin and the biocompatibility of the vessels were carefully assessed, including activated partial thromboplastin time, thrombin time, hemolysis, platelet adhesion experiments, and the morphologies of red blood cells. A concept of new drug-release agents with soft core and hard shell is proposed and offers guidance for the design of novel drug-delivery systems.
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Anti-Inflamatórios não Esteroides/química , Heparina/química , Ibuprofeno/química , Dióxido de Silício/química , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de SuperfícieRESUMO
OBJECTIVE: An increasing number of studies have shown the potential diagnostic value of cell-free DNA (cfDNA) as a new biomarker in the management of thyroid cancer (TC); however, the accuracy of research results is inconsistent. This meta-analysis is the first to synthesize published results and evaluate the application value of circulating cfDNA in the diagnosis of TC. METHODS: A search strategy was developed according to PICO (P: Patient; I: Intervention; C: Comparison; O: Outcome) principles. We searched 5 databases until October 2022. Original studies that examined cfDNA for the diagnosis of TC and used pathology as the gold standard were included in this meta-analysis. A random-effects model was used to pool the data extracted from individual studies, including the number of patients and the numbers of true positives, false positives, true negatives, and false negatives. RESULTS: A total of 622 patients with TC, 547 patients with benign thyroid nodules, and 98 healthy individuals were included in 20 studies reported in 14 articles. The types of cfDNA included in the research include specific mutations of cfDNA, methylation of cfDNA, the content of cfDNA, and cfDNA index. After rigorous statistical analysis, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the summary receiver operating characteristic curve were 0.76 (95% confidence interval [CI] 0.62-0.85), 0.87 (95% CI 0.78-0.93), 5.08 (95% CI 3.3-10.3), 0.28 (95% CI 0.17-0.46), 21 (95% CI 9-49), and 0.89 (95% CI 0.86-0.91), respectively. The meta-regression results showed that the number of cfDNAs, cfDNA methylation status, and sample size were the sources of heterogeneity in the specificity of the study. A subgroup analysis showed that the quantitative analysis group (cfDNA level) had a higher diagnostic accuracy than that of the qualitative analysis group (cfDNA methylation, mutation, or integrity index), with a sensitivity of 0.84, specificity of 0.89, and area under the curve of 0.91. CONCLUSIONS: The results of this meta-analysis suggest that cfDNA has value as an adjunct for the diagnosis of TC. Quantitative detection of cfDNA can achieve relatively high diagnostic accuracy. However, due to heterogeneity, the test results based on cfDNA for TC should be interpreted with caution.
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Ácidos Nucleicos Livres , Neoplasias da Glândula Tireoide , Humanos , Curva ROC , Biomarcadores Tumorais/genética , Mutação , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/genética , Sensibilidade e EspecificidadeRESUMO
Self-propelled separation materials, that is, motor, are one of the keys to realizing smart oil-water separation. Although three-dimensional sponges such as commercial melamine sponge (MS) exhibit excellent oil-water separation ability, they cannot move by themselves on water. Aiming at solving this problem, a polydimethylsiloxane (PDMS) and molybdenum disulfide (MoS2) modified MS motor (PDMS@MS/MoS2) with an asymmetric multilayer structure was prepared, in which the photothermal layer MoS2 provided the propelling force for the motor under infrared light irradiation, and the middle layer PDMS was used as the superhydrophobic modified agent and adhesive agent between commercial MS and MoS2 powder. PDMS coated MS (PDMS@MS) as the superhydrophobic layer showed good superhydrophobic ability (153.1°) and oil-water separation capacity (52.33 g/g to liquid paraffin). Furthermore, the introduction of MoS2 made the speed of the sponge motor reach 8.27 mm s-1 with a removal quantity of 12.20 g/g for cyclohexane. After recycling 8 times, the contact angle, cyclohexane capturing amount, and average velocity of the motor were 150.3°, 11.40 g/g, and 8.41 mm/s, respectively. Meanwhile, PDMS@MS/MoS2 kept a similar light-propelling velocity (â¼8 mm) at different pH values and in simulated seawater, demonstrating that the light-propelling motor possessed a good cycle and practical performance, which provides a possibility for the directional light propulsion of a sponge motor in oil-water separation.
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Background: Patients with non-small cell lung cancer (NSCLC) who develop brain metastases (BM) have a poor prognosis. This study aimed to construct a clinical prediction model to determine the overall survival (OS) of NSCLC patients with BM. Methods: A total of 300 NSCLC patients with BM at the Yunnan Cancer Centre were retrospectively analysed. The prediction model was constructed using the least absolute shrinkage and selection operator-Cox regression. The bootstrap sampling method was employed for internal validation. The performance of our prediction model was compared using recursive partitioning analysis (RPA), graded prognostic assessment (GPA), the update of the graded prognostic assessment for lung cancer using molecular markers (Lung-molGPA), the basic score for BM (BSBM), and tumour-lymph node-metastasis (TNM) staging. Results: The prediction models comprising 15 predictors were constructed. The area under the curve (AUC) values for the 1-year, 3-year, and 5-year time-dependent receiver operating characteristic (curves) were 0.746 (0.678-0.814), 0.819 (0.761-0.877), and 0.865 (0.774-0.957), respectively. The bootstrap-corrected AUC values and Brier scores for the prediction model were 0.811 (0.638-0.950) and 0.123 (0.066-0.188), respectively. The time-dependent C-index indicated that our model exhibited significantly greater discrimination compared with RPA, GPA, Lung-molGPA, BSBM, and TNM staging. Similarly, the decision curve analysis demonstrated that our model displayed the widest range of thresholds and yielded the highest net benefit. Furthermore, the net reclassification improvement and integrated discrimination improvement analyses confirmed the enhanced predictive power of our prediction model. Finally, the risk subgroups identified by our prognostic model exhibited superior differentiation of patients' OS. Conclusion: The clinical prediction model constructed by us shows promise in predicting OS for NSCLC patients with BM. Its predictability is superior compared with RPA, GPA, Lung-molGPA, BSBM, and TNM staging.
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Neoplasias Encefálicas , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Estudos Retrospectivos , Prognóstico , Modelos Estatísticos , China/epidemiologiaRESUMO
PURPOSE: To investigate the risk factors of second primary malignant tumor (SPMT) in patients with differentiated thyroid cancer (DTC) and establish a competing risk nomogram to predict the probability of SPMT occurrence. METHODS: We retrieved data from the Surveillance, Epidemiology, and End Results (SEER) database for patients diagnosed with DTC between 2000 and 2019. The Fine and Gray subdistribution hazard model was employed to identify SPMT risk factors in the training set and develop a competing risk nomogram. Model evaluation was performed using area under the receiver operating characteristic curve (AUC), calibration curve, and decision curve analysis (DCA). RESULTS: A total of 112,257 eligible patients were included in the study and randomized into a training set (n = 112,256) and a validation set (n = 33,678). The cumulative incidence rate of SPMT was 15% (n = 9528). Age, sex, race, tumor multifocality, and TNM stage were independent risk factors of SPMT. The calibration plots showed good agreement between the predicted and observed SPMT risks. The 10-year AUCs of the calibration plots were 70.2 (68.7-71.6) in the training set and 70.2 (68.7-71.5) in the validation set. Moreover, DCA showed that our proposed model resulted in higher net benefits within a defined range of risk thresholds. The cumulative incidence rate of SPMT differed among risk groups, classified according to nomogram risk scores. CONCLUSION: The competing risk nomogram developed in this study exhibits high performance in predicting the occurrence of SPMT in patients with DTC. These findings may help clinicians identify patients at distinct levels of risk of SPMT and develop corresponding clinical management strategies.
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Adenocarcinoma , Segunda Neoplasia Primária , Neoplasias da Glândula Tireoide , Humanos , Neoplasias da Glândula Tireoide/epidemiologia , Segunda Neoplasia Primária/epidemiologia , Pesquisa , Área Sob a Curva , Nomogramas , Programa de SEERRESUMO
Correction for 'All-purpose nanostrategy based on dose deposition enhancement, cell cycle arrest, DNA damage, and ROS production as prostate cancer radiosensitizer for potential clinical translation' by Xiao-xiao Guo et al., Nanoscale, 2021, 13, 14525-14537, https://doi.org/10.1039/D1NR03869A.
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Hydrophilic bone morphogenetic protein 2 (BMP2) is easily degraded and difficult to load onto hydrophobic carrier materials, which limits the application of polyester materials in bone tissue engineering. Based on soybean-lecithin as an adjuvant biosurfactant, we designed a novel cell-free-scaffold of polymer of poly(ε-caprolactone) and poly(lactide-co-glycolide)-co-polyetherimide with abundant entrapped and continuously released BMP2 for in vivo stem cell-capture and in situ osteogenic induction, avoiding the use of exogenous cells. The optimized bioactive osteo-polyester scaffold (BOPSC), i.e. SBMP-10SC, had a high BMP2 entrapment efficiency of 95.35%. Due to its higher porosity of 83.42%, higher water uptake ratio of 850%, and sustained BMP2 release with polymer degradation, BOPSCs were demonstrated to support excellent in vitro capture, proliferation, migration and osteogenic differentiation of mouse adipose derived mesenchymal stem cells (mADSCs), and performed much better than traditional BMP-10SCs with unmodified BMP2 and single polyester scaffolds (10SCs). Furthermore, in vivo capture and migration of stem cells and differentiation into osteoblasts was observed in mice implanted with BOPSCs without exogenous cells, which enabled allogeneic bone formation with a high bone mineral density and ratios of new bone volume to existing tissue volume after 6 months. The BOPSC is an advanced 3D cell-free platform with sustained BMP2 supply for in situ stem cell capture and osteoinduction in bone tissue engineering with potential for clinical translation.
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Radiotherapy (RT) is one of the main treatments for men with prostate cancer (PCa). To date, numerous sophisticated nano-formulations as radiosensitizers have been synthesized with inspiring therapeutic effects both in vitro and in vivo; however, almost all the attention has been paid on the enhanced dose deposition effect by secondary electrons of nanomaterials with high atomic numbers (Z); despite this, cell-cycle arrest, DNA damage, and also reactive oxygen species (ROS) production are critical working mechanisms that account for radiosensitization. Herein, an 'all-purpose' nanostrategy based on dose deposition enhancement, cell cycle arrest, and ROS production as prostate cancer radiosensitizer for potential clinical translation was proposed. The rather simple structure of docetaxel-loaded Au nanoparticles (NPs) with prostate specific membrane antigen (PSMA) ligand conjugation have been successfully synthesized. Enhanced cellular uptake achieved via the selective internalization of the NPs by PCa cells with positive PSMA expression could guarantee enhanced dose deposition. Moreover, the as-synthesized nanosystem could effectively arrest the cell cycle at G2/M phases, which would reduce the ability of DNA damage repair for more irradiation sensitive of the PCa cells. Moreover, the G2/M phase arrest would further promote cascade retention and the enrichment of NPs within the cells. Furthermore, ROS generation and double strand breaks greatly promoted by NPs under irradiation (IR) could also provide an underlying basis for effective radiosensitizers. In vitro and in vivo investigations confirmed the as-synthesized NPs as an effective nano-radiosensitizer with ideal safety. More importantly, all moieties within the present nanosystem have been approved by FDA for the purpose of PCa treatment, thus making it highly attractive for clinical translation.
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Nanopartículas Metálicas , Neoplasias da Próstata , Pontos de Checagem do Ciclo Celular , Dano ao DNA , Ouro , Humanos , Masculino , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Neoplasias da Próstata/radioterapia , Espécies Reativas de OxigênioRESUMO
The high-efficiency capture of Tobacco Specific Nitrosamines by Hß zeolite in solution is reported for the first time, along with the adsorption of 4-methylnitrosamino-1-3-pyridyl-1-butanone in aqueous solution. Different from other zeolites such as NaZSM-5, the specific pore size of Hß exerted a crucial function endowing the zeolite a higher removal of TSNA and selectivity of NNK. The adsorption thermodynamics of NNK by Hß in aqueous adsorption was fitted to Temkin adsorption model with a linearly decreasing isosteric heat of adsorption. In addition, the adsorptive capacity of Hß zeolite for NNK reached over 70 mg g-1, offering a powerful sorbent of TSNA to protect environment.
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Carcinógenos/química , Nicotiana/química , Nitrosaminas/química , Zeolitas/química , Adsorção , Soluções , TermodinâmicaRESUMO
AIMS: The objective of this study was to analyze the efficacy of polypyrrole/polylactic acid (PPy/PLA) nanofibrous scaffold cotransplanted with bone marrow stromal cells (BMSCs) in promoting the functional recovery in a rat spinal cord injury (SCI). METHODS: Female Sprague-Dawley rats were randomly divided into three groups (n = 18/group): control group, PPy/PLA group, and PPy/PLA/BMSCs group. The SCI was induced in all rats. Consequently, rats in PPy/PLA/BMSCs group were transplanted with 1 × 105 BMSCs after implantation of PPy/PLA, while those in the PPy/PLA group were implanted with PPy/PLA only; no implantation was performed in the control group. Six weeks after surgery, immunofluorescence microscopy, electron microscope, and polymerase chain reaction (PCR) techniques were performed to assess the changes in the injured spinal cord tissues. RESULTS: Electrophysiology and locomotor function testing suggested that PPy/PLA nanofibrous scaffold cotransplanted with BMSCs could promote the functional recovery of the spinal cord. Six weeks after the operation, lower amount of scar tissue was found in the PPy/PLA group compared with the control group. Abundant neurofilament (NF) and neuron-specific marker (NeuN) positive staining, and myelin formations were detected in the injured area. In addition, the transplantation of BMSCs not only improved the efficacy of PPy/PLA but also managed to survive well and was differentiated into neural and neuroglial cells. CONCLUSIONS: The implantation of PPy/PLA nanofibrous scaffold and BMSCs has a great potential to restore the electrical conduction and to promote functional recovery by inhibiting the scar tissue formation, promoting axon regeneration, and bridging the gap lesion.
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Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/fisiologia , Nanofibras/administração & dosagem , Recuperação de Função Fisiológica/fisiologia , Traumatismos da Medula Espinal/terapia , Alicerces Teciduais , Animais , Células Cultivadas , Feminino , Poliésteres/administração & dosagem , Polímeros/administração & dosagem , Pirróis/administração & dosagem , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica/efeitos dos fármacos , Traumatismos da Medula Espinal/fisiopatologiaRESUMO
Understanding the interaction between biomaterials and the immune system has become increasingly important. Mineralized collagen (MC) has the same chemical components and microstructures to natural bone tissue, and is considered as a better biomaterial for bone prostheses compared to hydroxyapatite (HA). However, there is little information about how MC affects inflammatory responses. In this study, we investigate the inflammatory responses to MC and HA by culturing RAW264.7 cells on their surfaces. We observed that MC increases CD206+ staining and IL-10 (M2 macrophages), whereas HA shows cells expressing more CD86 and secreting more TNF-α. This result indicates that MC may attenuate inflammatory responses to implanted bone prostheses.
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Substitutos Ósseos/química , Colágeno/química , Durapatita/química , Macrófagos/metabolismo , Animais , Antígeno B7-2/metabolismo , Materiais Biocompatíveis , Adesão Celular , Citocinas/metabolismo , Inflamação , Interleucina-10/metabolismo , Lectinas Tipo C/metabolismo , Macrófagos/citologia , Receptor de Manose , Lectinas de Ligação a Manose/metabolismo , Camundongos , Monócitos/citologia , Osteogênese , Fenótipo , Células RAW 264.7 , Receptores de Superfície Celular/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
New shape-selectivity of graphene-based materials was discovered on this article. To explore the new selectivity, the structure and surface state of graphene and carbon nanotube were examined firstly, and their specific selectivity was verified and was compared with that of ZSM-5 zeolite in aqueous solutions of tobacco specific nitrosamines (TSNA) along with dyes. These two adsorbents trapped about 55% and 70% of 4-methylnitrosamino-1-3-pyridyl-1-butanone (NNK) but only 3% of N'-nitrosonornicotine (NNN) in solution, having an obvious selectivity for the former, due to its stronger interaction with graphene. NNK on graphene sheet obtained more electrons (0.015 e) and owned larger adsorption energy (15.63 kcal mol-1) than that of NNN (0.003 e, 9.19 kcal mol-1), according to theoretical calculation and FTIR results. More 95 or 136 mg g -1 acid red 88 than methyl orange was captured by graphene or carbon nanotube, demonstrating this special and abnormal selectivity again. With new selectivity, graphene showed a higher capacity (6.9%) and shorter adorption equilibrium time (5 min) for TSNA than the typical selecive sorbent ZSM-5 zeolite (1.7% and 20 min) in tobacco solution but kept the similar selctivity to NNK, paving a new way to control the carcinogens like TSNA in environment.
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Grafite/química , Nanotubos de Carbono/química , Nicotiana/química , Nitrosaminas/análise , Adsorção , Modelos Teóricos , Estrutura Molecular , Soluções , Propriedades de SuperfícieRESUMO
To meet the requirement of capturing tobacco-specific nitrosamines (TSNA) for environment protection, a unique microenvironment was carefully created inside the channels of mesoporous silica MCM-41. In situ carbonization of template micelles at 923 K, combined with the excess aluminum used in one-pot synthesis of MCM-41, is adopted to tailor the tortuosity of mecsoporous channels, while loaded metal oxides (5 wt %) and the Al component in the framework are employed to exert the necessary electrostatic interaction toward the target carcinogens TSNA in solution. The elaborated microenvironment created in mesoporous sorbents was characterized with XRD, N2 adsorption-desorption, TEM, XPS, and TG-DSC methods. Various solutions of Burley- and Virginia-type tobaccos were used to assess the adsorption performance of new mesoporous sorbents, and the influence of the solid-to-liquid ratio, adsorption time, and loading amount of CuO on the adsorption was carefully examined. The representative sample 5%Cu/AM-10c could capture 27.2% of TSNA in Burley tobacco solution, and its capacity reached 0.3 mg g-1 in Snus tobacco extract solution, offering a promising candidate for the protection of the environment and public health.
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Polypyrrole (PPy) is a biocompatible polymer with good conductivity. Studies combining PPy with electrospinning have been reported; however, the associated decrease in PPy conductivity has not yet been resolved. We embedded PPy into poly(lactic acid) (PLA) nanofibers via electrospinning and fabricated a PLA/PPy nanofibrous scaffold containing 15% PPy with sustained conductivity and aligned topography. There was good biocompatibility between the scaffold and human umbilical cord mesenchymal stem cells as well as Schwann cells. Additionally, the direction of cell elongation on the scaffold was parallel to the direction of fibers. Our findings suggest that the aligned PLA/PPy nanofibrous scaffold is a promising biomaterial for peripheral nerve regeneration.
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A new synthetic strategy, named "carbonization in limited space" and based on the specific interaction between eutectic salt and dual-ionic liquids (dual-ILs), is reported in this article. N-Containing dual-ILs (1,4-diethyl-1,4-diazaniabicyclo[2,2,2]octane imidazolide-4,5-dicyanoiazolide, [2C2DABCO](2+)[Im](-)[CN-Im](-)) were synthesized as new carbon-nitrogen precursors, while eutectic salt was chosen as a reuseable template in order to facilely fabricate the N-doped porous carbon with sheetlike morphology. Nitrogen can be directly and efficiently incorporated into the porous carbon, resulting in the materials with suitable N content, tunable pore structure, and controllable thickness of sheet as well as high surface area. They exhibited good performance as electrodes for supercapacitors, photocatalysts in degradation of methyl orange (MO) under visible light, and the sorbent to capture tobacco-specific N-nitrosamines (TSNAs) in solution, offering a new simplified but effective method to prepare versatile carbon material.