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1.
Histopathology ; 2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38660975

RESUMEN

AIMS: Immunotherapy has brought a new era to cancer treatment, yet we lack dependable predictors for its effectiveness. This study explores the predictive significance of intratumour stroma proportion (iTSP) for treatment success and prognosis in non-small cell lung cancer (NSCLC) patients undergoing treatment with immune check-point inhibitors (ICIs) together with chemotherapy. METHODS AND RESULTS: We retrospectively collected data from patients with unresectable stage IIIB-IV NSCLC who were treated with first-line ICIs and chemotherapy. Each patient received a confirmed pathological diagnosis, and the pathologist evaluated the iTSP on haematoxylin and eosin (H&E)-stained sections of diagnostic tissue slides. Among the 102 H&E-stained biopsy samples, 61 (59.8%) were categorised as stroma-L (less than 50% iTSP), while 41 (40.2%) were classified as stroma-H (more than 50% iTSP). We observed that the stroma-L group exhibited a significantly better objective response rate (ORR) (72.1 versus 51.2%, P = 0.031) and deeper response depth (DpR) (-50.49 ± 28.79% versus -35.83 ± 29.91%, P = 0.015) compared to the stroma-H group. Furthermore, the stroma-L group showed longer median progression-free survival (PFS) (9.6 versus 6.0 months, P = 0.011) and overall survival (OS) (24.0 versus 12.2 months, P = 0.001) compared to the stroma-H group. Multivariate Cox proportional hazards regression analysis indicated that iTSP was a highly significant prognostic factor for both PFS [hazard ratio (HR) = 1.713; P = 0.030] and OS (HR = 2.225; P = 0.003). CONCLUSION: Our findings indicate that a lower iTSP corresponds to improved clinical outcomes and greater DpR in individuals with stage IIIB-IV NSCLC treated with first-line ICIs and chemotherapy. The iTSP could potentially serve as a predictive biomarker for ICIs therapy response.

2.
Chem Commun (Camb) ; 60(24): 3275-3278, 2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38421011

RESUMEN

Interactions of ZnO nanorods with water and the dynamic migration characteristic of surface oxygen species are important in controlling its structure and catalytic properties. Here, we apply 17O solid-state NMR spectroscopy to investigate the interactions, as well as oxygen ion diffusion properties of ZnO nanorods under different conditions.

3.
Clin. transl. oncol. (Print) ; 26(1): 214-224, jan. 2024.
Artículo en Inglés | IBECS | ID: ibc-229159

RESUMEN

Objective Nasal or extranasal natural killer/T-cell lymphoma (NKTCL) is a very rare aggressive lymphoma, but it is increasingly diagnosed. To evaluate some specificity by comparative analysis between primary upper aerodigestive tract (UAT) and non-upper aerodigestive tract (NUAT)NKTCL. Methods A retrospective analysis was performed on NKTCL patients from January 2013 to November 2022 in our cancer center. Results The majority of the lesions were UAT-NKTCL 70 cases (92.1%), the primary NUAT occurred in 6 cases. Patients in the UAT group were mainly in the early stage and in the low and medium risk, while those in the NUAT group were late stage and in high risk (p = 0.000). The expressions of CD3 and TIA-1 in UAT group were higher than those in NUAT group (p = 0.031, p = 0.003), while CD7 was dominant in NUAT group (p = 0.009). For early stage NKTCL, multivariate analysis suggested that gender and PINK score were independent factors affecting PFS and OS (p < 0.05). The 3 year OS rate in initial CR group was 90.1% versus 46.4% in non-CR group (p = 0.000). In advanced stage, KI67% and bone marrow involvement were independent factors affecting OS (p = 0.022, p = 0.038). Conclusion It was difficult to distinguish between UAT and NUAT-NKTCL from histopathology. NUAT-NKTCL patients did have advanced stage and poor outcome. The prognostic value of PINK score and bone marrow involvement was proposed. We aimed to improve initial CR rates, as well as to find new predictive models to predict the whole population (AU)


Asunto(s)
Humanos , Linfoma Extranodal de Células NK-T/diagnóstico , Linfoma Extranodal de Células NK-T/patología , Estudios Retrospectivos , Pronóstico
4.
Clin Transl Oncol ; 26(1): 214-224, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37351807

RESUMEN

OBJECTIVE: Nasal or extranasal natural killer/T-cell lymphoma (NKTCL) is a very rare aggressive lymphoma, but it is increasingly diagnosed. To evaluate some specificity by comparative analysis between primary upper aerodigestive tract (UAT) and non-upper aerodigestive tract (NUAT)NKTCL. METHODS: A retrospective analysis was performed on NKTCL patients from January 2013 to November 2022 in our cancer center. RESULTS: The majority of the lesions were UAT-NKTCL 70 cases (92.1%), the primary NUAT occurred in 6 cases. Patients in the UAT group were mainly in the early stage and in the low and medium risk, while those in the NUAT group were late stage and in high risk (p = 0.000). The expressions of CD3 and TIA-1 in UAT group were higher than those in NUAT group (p = 0.031, p = 0.003), while CD7 was dominant in NUAT group (p = 0.009). For early stage NKTCL, multivariate analysis suggested that gender and PINK score were independent factors affecting PFS and OS (p < 0.05). The 3 year OS rate in initial CR group was 90.1% versus 46.4% in non-CR group (p = 0.000). In advanced stage, KI67% and bone marrow involvement were independent factors affecting OS (p = 0.022, p = 0.038). CONCLUSION: It was difficult to distinguish between UAT and NUAT-NKTCL from histopathology. NUAT-NKTCL patients did have advanced stage and poor outcome. The prognostic value of PINK score and bone marrow involvement was proposed. We aimed to improve initial CR rates, as well as to find new predictive models to predict the whole population.


Asunto(s)
Linfoma Extranodal de Células NK-T , Humanos , Estudios Retrospectivos , Linfoma Extranodal de Células NK-T/diagnóstico , Linfoma Extranodal de Células NK-T/patología , Pronóstico
5.
J Am Chem Soc ; 144(51): 23340-23351, 2022 12 28.
Artículo en Inglés | MEDLINE | ID: mdl-36512749

RESUMEN

ZnO plays a very important role in many catalytic processes involving H2, yet the details on their interactions and H2 activation mechanism are still missing, owing to the lack of a characterization method that provides resolution at the atomic scale and follows the fate of oxide surface species. Here, we apply 17O solid-state NMR spectroscopy in combination with DFT calculations to unravel the surface structure of ZnO nanorods and explore the H2 activation process. We show that six different types of oxygen ions in the surface and subsurface of ZnO can be distinguished. H2 undergoes heterolytic dissociation on three-coordinated surface zinc and oxygen ions, while the formed hydride species migrate to nearby oxygen species, generating a second hydroxyl site. When oxygen vacancies are present, homolytic dissociation of H2 occurs and zinc hydride species form from the vacancies. Reaction mechanisms on oxide surfaces can be explored in a similar manner.


Asunto(s)
Óxido de Zinc , Catálisis , Óxidos , Oxígeno , Zinc
6.
Nat Commun ; 13(1): 6093, 2022 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-36241633

RESUMEN

Layered double oxides (LDOs) can restore the parent layered double hydroxides (LDHs) structure under hydrous conditions, and this "memory effect" plays a critical role in the applications of LDHs, yet the detailed mechanism is still under debate. Here, we apply a strategy based on ex situ and in situ solid-state NMR spectroscopy to monitor the Mg/Al-LDO structure changes during recovery at the atomic scale. Despite the common belief that aqueous solution is required, we discover that the structure recovery can occur in a virtually solid-state process. Local structural information obtained with NMR spectroscopy shows that the recovery in aqueous solution follows dissolution-recrystallization mechanism, while the solid-state recovery is retro-topotactic, indicating a true "memory effect". The amount of water is key in determining the interactions of water with oxides, thus the memory effect mechanism. The results also provide a more environmentally friendly and economically feasible LDHs preparation route.

7.
Cancer Manag Res ; 14: 2639-2648, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36090469

RESUMEN

Purpose: This study aimed to analyze the clinical features and survival of primary small intestinal diffuse large B-cell lymphoma (PsI-DLBCL), and establish and independently validate a prognostic nomogram for individual risk prediction. Patients and methods: Data for 24 patients from the Renmin Hospital of Wuhan University were used as an independent validation cohort, data for 1144 patients with PsI-DLBCL from the SEER database were randomly assigned to training (N=817) and internal validation (N=327) sets. The survival nomogram was constructed with the most significant factors associated with OS using Univariate and multivariate analyses on the training set. Decision curve analysis (DCA) was conducted. Internal validation was SEER validation set. Our cancer center cohort was used as an external validation set to further verify the survival nomogram. Results: Five clinicopathological feature factors associated with OS of the training set yielded (age, marital status, Ann Arbor stage, surgery for primary site and chemotherapy), which were used to create a survival nomogram. Additionally, the calibration curves of the prognostic nomogram revealed good agreement between the predicted survival probabilities and the ground truth values. The stability of our survival nomogram was explained by internal and external validation data. Conclusion: Our nomogram proposes the clinical and therapeutic factors affecting OS for patients with PsI-DLBCL. It shows that chemotherapy and surgery are beneficial to patients in the choice of treatment options. These results suggest that a survival nomogram may be better at predicting OS for PsI-DLBCL patients.

8.
Int J Biol Sci ; 17(10): 2606-2621, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34326697

RESUMEN

Cisplatin (DDP) was reported to improve pathological complete response (pCR) rates in triple-negative breast cancer (TNBC) patients, however, the molecular mechanism still remains largely unknown. Emerging evidence suggested that some chemotherapeutic drugs played anti-tumor effects by inducing cell pyroptosis. Nevertheless, whether pyroptosis contributes to the DDP-induced anti-tumor effect in TNBC remains unexploited. In the present study, NLRP3/caspase-1/GSDMD pyroptosis pathway was involved in the DDP-induced anti-tumor effect of TNBC in vitro and in vivo, providing evidence that DDP might induce pyroptosis in TNBC. Moreover, DDP activated NLRP3/caspase-1/GSDMD pyroptosis pathway by up-regulating the long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3). Furthermore, knockdown of MEG3 not only partly abolished the activation effect of DDP on NLRP3/caspase-1/GSDMD pathway-mediated pyroptosis, but also reversed the suppression of DDP on tumor growth and metastasis ability in vitro and in vivo, further confirming that MEG3 may partially mediate the pyroptotic signaling upon DDP treatment. Thus, our data uncovered a novel mechanism that DDP induced pyroptosis via activation of MEG3/NLRP3/caspase-1/GSDMD pathway in TNBC to exert anti-tumor effects, which may help to develop new strategies for the therapeutic interventions in TNBC.


Asunto(s)
Cisplatino/farmacología , Piroptosis/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Neoplasias de la Mama Triple Negativas/metabolismo , Animales , Caspasa 1/metabolismo , Línea Celular Tumoral , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Proteínas de Unión a Fosfato/metabolismo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , ARN Largo no Codificante/metabolismo , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/patología , Ensayos Antitumor por Modelo de Xenoinjerto
9.
Medicine (Baltimore) ; 100(19): e25908, 2021 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-34106653

RESUMEN

ABSTRACT: Early prediction of non-response is essential in order to avoid inefficient treatments. The objective of this study was to determine the contrast-enhanced ultrasound (CEUS) for early predicting pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) in breast cancer patients.Between March 2018 and October 2019, 93 consecutive patients with histologically proven breast cancer scheduled for NAC were enrolled. Conventional ultrasound and CEUS imaging were performed before NAC and after two cycles of NAC. CEUS parameters were compared with pathologic response. Multiple logistic regression analyses were utilized to explore CEUS parameters to predict pCR, and receiver operating characteristic analysis was used to evaluate the predictive ability.Therapeutic response was obtained from 25 (27%) patients with pCR and 68 (73%) with non-pCR. Compared to non-pCR, pCR cases have a significantly higher proportion of homogeneous enhancement feature (56% vs 14%, P < .001) and centripetal enhancement (52% vs 23%, P = .012). A significant decrease in peak intensity (PI) was observed after two cycles of NAC. Compared with non-pCR patients, the kinetic parameters PI change (PI%) was higher in pCR patients (P < .001). Multiple logistic regression demonstrated two independent predictors of pCR: internal homogeneity (odds ratio, 4.85; 95% confidence interval: 1.20-19.65; P = .027) and PI% (odds ratio, 1.08; 95% confidence interval: 1.02-1.15; P = .007). In receiver operating characteristic curve analysis, internal homogeneity and PI%, with area under curve of 0.71 and 0.84, predicted pCR with sensitivity (56%, 95%) and specificity (85%, 70%), respectively.Internal homogeneity and PI% of CEUS may be useful in the noninvasive early prediction of pCR in patients with breast cancer.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/patología , Quimioterapia Adyuvante/métodos , Ultrasonografía/métodos , Adulto , Anciano , Medios de Contraste , Ciclofosfamida/uso terapéutico , Epirrubicina/uso terapéutico , Femenino , Fluorouracilo/uso terapéutico , Humanos , Modelos Logísticos , Metástasis Linfática , Persona de Mediana Edad , Estadificación de Neoplasias
10.
Clin Epigenetics ; 13(1): 104, 2021 05 05.
Artículo en Inglés | MEDLINE | ID: mdl-33952317

RESUMEN

BACKGROUND: Definitive diagnosis of primary central nervous system lymphoma (PCNSL) requires invasive surgical brain biopsy, causing treatment delays. In this paper, we identified and validated tumor-specific markers that can distinguish PCNSL from other CNS tumors in tissues. In a pilot study, we tested these newly identified markers in plasma. RESULTS: The Methylation Outlier Detector program was used to identify markers in TCGA dataset of 48 diffuse large B-cell lymphoma (DLBCL) and 656 glioblastomas and lower-grade gliomas. Eight methylated markers clearly distinguished DLBCL from gliomas. Marker performance was verified (ROC-AUC of ≥ 0.989) in samples from several GEO datasets (95 PCNSL; 2112 other primary CNS tumors of 11 types). Next, we developed a novel, efficient assay called Tailed Amplicon Multiplexed-Methylation-Specific PCR (TAM-MSP), which uses two of the methylation markers, cg0504 and SCG3 triplexed with ACTB. FFPE tissue sections (25 cases each) of PCNSL and eight types of other primary CNS tumors were analyzed using TAM-MSP. TAM-MSP distinguished PCNSL from the other primary CNS tumors with 100% accuracy (AUC = 1.00, 95% CI 0.95-1.00, P < 0.001). The TAM-MSP assay also detected as few as 5 copies of fully methylated plasma DNA spiked into 0.5 ml of healthy plasma. In a pilot study of plasma from 15 PCNSL, 5 other CNS tumors and 6 healthy individuals, methylation in cg0504 and SCG3 was detectable in 3/15 PCNSL samples (20%). CONCLUSION: The Methylation Outlier Detector program identified methylated markers that distinguish PCNSL from other CNS tumors with accuracy. The high level of accuracy achieved by these markers was validated in tissues by a novel method, TAM-MSP. These studies lay a strong foundation for a liquid biopsy-based test to detect PCNSL-specific circulating tumor DNA.


Asunto(s)
Neoplasias del Sistema Nervioso Central/diagnóstico , Neoplasias del Sistema Nervioso Central/genética , Metilación de ADN/genética , Epigenómica/métodos , Linfoma/diagnóstico , Linfoma/genética , Adolescente , Adulto , Anciano , Biomarcadores de Tumor/genética , Niño , Preescolar , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Reproducibilidad de los Resultados , Adulto Joven
12.
Diagn Pathol ; 16(1): 8, 2021 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-33441152

RESUMEN

AIMS: To explore the clinical characteristics and placental pathological changes of pregnant women with 2019 novel coronavirus (CoV) disease (COVID-19) in the third trimester, and to assess the possibility of vertical transmission. METHODS AND RESULTS: The placenta tissues were evaluated by using immunohistochemistry for inflammatory cells and Hofbauer cells, and using severe acute respiratory syndrome (SARS) CoV-2 RNA Fluorescence In-Situ Hybridization (FISH) and SARS-CoV-2 spike protein immunofluorescence (IF) double staining. All eight placentas from the third trimester pregnancy women were studied. All patients were cured, no clinical or serological evidence pointed to vertical transmission of SARS-CoV-2. Features of maternal vascular malperfusion (MVM) such as increased syncytial knots were present in all 8 cases (8/8), and increased focal perivillous fibrin depositions were presented in 7 cases (7/8). No significate chronic histiocytic intervillositis was noted in the placenta. The number of macrophages and inflammatory cells such as T cells, B cells and plasma cells in the placental villous was not significantly increased in all cases. Moreover, all of eight cases demonstrated negative results by FISH using a SARS-CoV-2 virus RNA probe and by IF using a monoclonal antibody against SARS-CoV-2 spike protein. CONCLUSIONS: We found no evidence of vertical transmission and adverse maternal-fetal outcomes in the placentas of third trimester COVID-19 pregnancy women, which provided further information for the clinical management of those women in the third trimester. However, further studies are still needed for patients with infections in different stage of gestation, especially in first and second trimester.


Asunto(s)
COVID-19/virología , Placenta/virología , Complicaciones Infecciosas del Embarazo/virología , SARS-CoV-2/patogenicidad , Adulto , Femenino , Humanos , Embarazo , Tercer Trimestre del Embarazo/inmunología , Mujeres Embarazadas , Glicoproteína de la Espiga del Coronavirus/metabolismo
13.
RSC Adv ; 11(40): 25004-25009, 2021 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-35481043

RESUMEN

Tin dioxide (SnO2) nanomaterials are important acid catalysts. It is therefore crucial to obtain details about the surface acidic properties in order to develop structure-property relationships. Herein, we apply 31P solid-state NMR spectroscopy combined with a trimethylphosphine (TMP) probe molecule, to study the facet-dependent acidity of SnO2 nanosheets and nanoshuttles. With the help of density functional theory calculations, we show that the tin cations exposed on the surfaces are Lewis acid sites and their acid strengths rely on surface geometries. As a result, the (001), (101), (110), and (100) facets can be differentiated by the 31P NMR shifts of adsorbed TMP molecules, and their fractions in different nanomaterials can be extracted according to deconvoluted 31P NMR resonances. The results provide new insights on nanosized oxide acid catalysts.

14.
Histopathology ; 77(5): 832-840, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32506505

RESUMEN

AIMS: Follicular dendritic cell (FDC) sarcoma is a rare neoplasm originating from follicular dendritic cells in germinal centres. It is classified as conventional and Epstein-Barr virus (EBV)-positive inflammatory FDC sarcoma according to the 2019 World Health Organization classification of digestive system tumours; the latter is rarer. So in view of the rarity and difficulty in diagnosis, the aim of the manuscript is to share our experience of diagnosing EBV-positive inflammatory FDC sarcoma. METHODS AND RESULTS: Here, we describe the clinicopathological features, gross description, histomorphology, immunophenotype, EBV-encoded mRNA (EBER) in-situ hybridisation, gene rearrangement and clinical follow-up of two patients with EBV-positive inflammatory FDC sarcoma in the colon, and review the relevant literature. The tumours were found in two males, aged 53 and 48 years, respectively, with a tumour diameter between 10 and 45 mm. Both cases occurred in the colon and presented as pedunculated colonic masses. Microscopically, scanty atypical ovoid to spindle neoplastic cells were mixed in a background of florid lymphoplasmacytic infiltration. The nuclei of these atypical cells showed vesicular chromatin and small, distinct nucleoli. Immunohistochemistry demonstrated that the atypical stromal cells were positive for CD21, CD23, CD35, and D2-40. EBER in-situ hybridisation also gave positive results in two cases. There was a mean follow-up of 9 months (range, 7-11 months). CONCLUSION: EBV-positive inflammatory FDC sarcoma is an extremely rare tumour with a distinct morphology and phenotype. Therefore, it is very important to recognise it particularly for correct diagnosis and prevention of misdiagnosis and mistreatment.


Asunto(s)
Neoplasias del Colon/diagnóstico , Neoplasias del Colon/virología , Sarcoma de Células Dendríticas Foliculares/diagnóstico , Sarcoma de Células Dendríticas Foliculares/virología , Infecciones por Virus de Epstein-Barr/complicaciones , Biomarcadores de Tumor/análisis , Neoplasias del Colon/patología , Sarcoma de Células Dendríticas Foliculares/patología , Humanos , Masculino , Persona de Mediana Edad
15.
J Am Chem Soc ; 142(25): 11173-11182, 2020 06 24.
Artículo en Inglés | MEDLINE | ID: mdl-32459963

RESUMEN

Hydrous materials are ubiquitous in the natural environment and efforts have previously been made to investigate the structures and dynamics of hydrated surfaces for their key roles in various chemical and physical applications, with the help of theoretical modeling and microscopy techniques. However, an overall atomic-scale understanding of the water-solid interface, including the effect of water on surface ions, is still lacking. Herein, we employ ceria nanorods with different amounts of water as an example and demonstrate a new approach to explore the water-surface interactions by using solid-state NMR in combination with density functional theory. NMR shifts and relaxation time analysis provide detailed information on the local structure of oxygen ions and the nature of water motion on the surface: the amount of molecularly adsorbed water decreases rapidly with increasing temperature (from room temperature to 150 °C), whereas hydroxyl groups are stable up to 150 °C, and dynamic water molecules are found to instantaneously coordinate to the surface oxygen ions. The applicability of dynamic nuclear polarization for selective detection of surface oxygen species is also compared to conventional NMR with surface selective isotopic-labeling: the optimal method depends on the feasibility of enrichment and the concentration of protons in the sample. These results provide new insight into the interfacial structure of hydrated oxide nanostructures, which is important to improve performance for various applications.

16.
Nat Commun ; 10(1): 5420, 2019 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-31780658

RESUMEN

Compared to nanomaterials exposing nonpolar facets, polar-faceted nanocrystals often exhibit unexpected and interesting properties. The electrostatic instability arising from the intrinsic dipole moments of polar facets, however, leads to different surface configurations in many cases, making it challenging to extract detailed structural information and develop structure-property relations. The widely used electron microscopy techniques are limited because the volumes sampled may not be representative, and they provide little chemical bonding information with low contrast of light elements. With ceria nanocubes exposing (100) facets as an example, here we show that the polar surface structure of oxide nanocrystals can be investigated by applying 17O and 1H solid-state NMR spectroscopy and dynamic nuclear polarization, combined with DFT calculations. Both CeO4-termination reconstructions and hydroxyls are present for surface polarity compensation and their concentrations can be quantified. These results open up new possibilities for investigating the structure and properties of oxide nanostructures with polar facets.

17.
Nat Commun ; 8(1): 581, 2017 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-28924155

RESUMEN

Facet engineering of oxide nanocrystals represents a powerful method for generating diverse properties for practical and innovative applications. Therefore, it is crucial to determine the nature of the exposed facets of oxides in order to develop the facet/morphology-property relationships and rationally design nanostructures with desired properties. Despite the extensive applications of electron microscopy for visualizing the facet structure of nanocrystals, the volumes sampled by such techniques are very small and may not be representative of the whole sample. Here, we develop a convenient 17O nuclear magnetic resonance (NMR) strategy to distinguish oxide nanocrystals exposing different facets. In combination with density functional theory calculations, we show that the oxygen ions on the exposed (001) and (101) facets of anatase titania nanocrystals have distinct 17O NMR shifts, which are sensitive to surface reconstruction and the nature of the steps on the surface. The results presented here open up methods for characterizing faceted nanocrystalline oxides and related materials.The exposed facets of oxide nanocrystals are key to their properties. Here, the authors use 17O solid-state NMR spectroscopy to discriminate between oxygen species on different facets of anatase titania nanocrystals, providing compelling evidence for the value of NMR spectroscopy in characterizing faceted oxides.

18.
ACS Appl Mater Interfaces ; 9(23): 19638-19645, 2017 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-28530792

RESUMEN

To explore the diversity and promising applications of pillararene-based molecular machines, phosphonated pillar[5]arenes (PPA[5]) were synthesized to construct novel supramolecular nanovalves for the first time, based on mesoporous silica nanoparticles (MSNs) functionalized with choline and pyridinium moieties, respectively. PPA[5] encircled the choline or pyridinium stalks to construct supramolecular nanovalves for encapsulation of drugs within the MSN pores. PPA[5] showed a high binding affinity for the quaternary ammonium stalks through the host-guest interactions primarily via ion pairing between the phosphonate and quaternary ammonium moieties, in comparison with carboxylated pillar[5]arene (CPA[5]), to minimize premature drug release. The specific ion pairing between the phosphonate and quaternary ammonium moieties was elaborated for the first time to construct supramolecular nanovalves. The supramolecular nanovalves were activated by low pH, Zn2+ coordination, and competitive agents for controlled drug release, and release efficiency and antitumor efficacy were further enhanced when gold nanorod (GNR)-embedded MSNs (GNR@MSNs) were used instead under illumination of near-infrared (NIR) light, attributed to the synergistic effect of photothermo-chemotherapy. The constructed PPA[5]-valved GNR@MSN delivery system has promising applications in tumor photothermo-chemotherapy.


Asunto(s)
Dióxido de Silicio/química , Calixarenos , Sistemas de Liberación de Medicamentos , Liberación de Fármacos , Concentración de Iones de Hidrógeno , Nanopartículas , Fosforilación , Porosidad
19.
Sci Adv ; 1(1): e1400133, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26601133

RESUMEN

Nanostructured oxides find multiple uses in a diverse range of applications including catalysis, energy storage, and environmental management, their higher surface areas, and, in some cases, electronic properties resulting in different physical properties from their bulk counterparts. Developing structure-property relations for these materials requires a determination of surface and subsurface structure. Although microscopy plays a critical role owing to the fact that the volumes sampled by such techniques may not be representative of the whole sample, complementary characterization methods are urgently required. We develop a simple nuclear magnetic resonance (NMR) strategy to detect the first few layers of a nanomaterial, demonstrating the approach with technologically relevant ceria nanoparticles. We show that the (17)O resonances arising from the first to third surface layer oxygen ions, hydroxyl sites, and oxygen species near vacancies can be distinguished from the oxygen ions in the bulk, with higher-frequency (17)O chemical shifts being observed for the lower coordinated surface sites. H2 (17)O can be used to selectively enrich surface sites, allowing only these particular active sites to be monitored in a chemical process. (17)O NMR spectra of thermally treated nanosized ceria clearly show how different oxygen species interconvert at elevated temperature. Density functional theory calculations confirm the assignments and reveal a strong dependence of chemical shift on the nature of the surface. These results open up new strategies for characterizing nanostructured oxides and their applications.

20.
Chem Commun (Camb) ; 51(33): 7203-6, 2015 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-25811958

RESUMEN

An integrated γ-cyclodextrin-gated mesoporous silica delivery system via dual dynamic covalent bonds was constructed with dual drug loading for simultaneous and cascade release in targeted combination drug therapy.


Asunto(s)
Portadores de Fármacos/química , Liberación de Fármacos , Nanopartículas/química , Dióxido de Silicio/química , gamma-Ciclodextrinas/química , Transporte Biológico , Portadores de Fármacos/metabolismo , Células HeLa , Humanos , Porosidad
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