RESUMEN
INTRODUCTION: Surgery for gliomas involving eloquent areas is a very challenging microsurgical procedure. Maximizing both the extent of resection (EOR) and preservation of neurological function have always been the focus of attention. Intraoperative neurophysiological monitoring (IONM) is widely used in this kind of surgery. The purpose of this study was to evaluate the efficacy of IONM in eloquent area glioma surgery. METHODS: Sixty-eight glioma patients who underwent surgical treatment from 2014 to 2019 were included in this retrospective cohort study, which focused on eloquent areas. Clinical indicators and IONM data were analysed preoperatively, two weeks after surgery, and at the final follow-up. Logistic regression, Cox regression, and KaplanâMeier analyses were performed, and nomograms were then established for predicting prognosis. The diagnostic value of the IONM indicator was evaluated by the receiver operating characteristic (ROC) curve. RESULTS: IONM had no effect on the postoperative outcomes, including EOR, intraoperative bleeding volume, duration of surgery, length of hospital stay, and neurological function status. However, at the three-month follow-up, the percentage of patients who had deteriorated function in the monitored group was significantly lower than that in the unmonitored group (23.3% vs. 52.6%; P < 0.05). Logistic regression analysis showed that IONM was a significant factor in long-term neurological function (OR = 0.23, 95% CI (0.07-0.70). In the survival analysis, long-term neurological deterioration indicated worsened overall survival (OS) and progression-free survival (PFS). A prognostic nomogram was established through Cox regression model analysis, which could predict the probability 3-year survival rate. The concordance index was 0.761 (95% CI 0.734-0.788). The sensitivity and specificity of IONM evoked potential (SSEP and TCeMEP) were 0.875 and 0.909, respectively. In the ROC curve analysis, the area under the curve (AUC) for the SSEP and TCeMEP curves was 0.892 (P < 0.05). CONCLUSIONS: The application of IONM could improve long-term neurological function, which is closely related to prognosis and can be used as an independent prognostic factor. IONM is practical and widely available for predicting postoperative functional deficits in patients with eloquent area glioma.
RESUMEN
Non-noble metal catalysts for promoting the sluggish kinetics of oxygen evolution reaction (OER) are essential to efficient water splitting for sustainable hydrogen production. Birnessite has a local atomic structure similar to that of an oxygen-evolving complex in photosystem II, while the catalytic activity of birnessite is far from satisfactory. Herein, we report a novel Fe-Birnessite (Fe-Bir) catalyst obtained by controlled Fe(III) intercalation- and docking-induced layer reconstruction. The reconstruction dramatically lowers the OER overpotential to 240 mV at 10 mA/cm2 and the Tafel slope to 33 mV/dec, making Fe-Bir the best of all the reported Bir-based catalysts, even on par with the best transition-metal-based OER catalysts. Experimental characterizations and molecular dynamics simulations elucidate that the catalyst features active Fe(III)-O-Mn(III) centers interfaced with ordered water molecules between neighboring layers, which lower reorganization energy and accelerate electron transfer. DFT calculations and kinetic measurements show non-concerted PCET steps conforming to a new OER mechanism, wherein the neighboring Fe(III) and Mn(III) synergistically co-adsorb OH* and O* intermediates with a substantially reduced O-O coupling activation energy. This work highlights the importance of elaborately engineering the confined interlayer environment of birnessite and more generally, layered materials, for efficient energy conversion catalysis.
RESUMEN
Efficient noble-metal free electrocatalyst for oxygen evolution reaction (OER) is critical for large-scale hydrogen production via water splitting. Inspired by Nature's oxygen evolution cluster in photosystem II and the highly efficient artificial OER catalyst of NiFe layered double hydroxide (LDH), we designed an electrostatic 2D-2D assembly route and successfully synthesized a 2D LDH(+)-Birnessite(-) hybrid. The as-constructed LDH(+)-Birnessite(-) hybrid catalyst showed advanced catalytic activity and excellent stability towards OER under a close to industrial hydrogen production condition (85 °C and 6â M KOH) for more than 20â h at the current densities larger than 100â mA cm-2 . Experimentally, we found that besides the enlarged interlayer distance, the flexible interlayer NiFe LDH(+) also modulates the electronic structure of layered MnO2 , and creates an electric field between NiFe LDH(+) and Birnessite(-), wherein OER occurs with a greatly decreased overpotential. DFT calculations confirmed the interlayer LDH modulations of the OER process, attributable to the distinct electronic distributions and environments. Upshifting the Fe-3d orbitals in LDH promotes electron transfer from the layered MnO2 to LDH, significantly boosting up the OER performance. This work opens a new way to fabricate highly efficient OER catalyst for industrial water oxidation.
RESUMEN
Carnitine functions as a mesoporogen in LTA zeolite synthesis whereas its structural analogue acetylcarnitine acts as a crystal growth modifier. An array of experimental and theoretical studies reveal a remarkable effect of molecular conformation on the actual roles of organic functional groups during zeolite crystallization.
RESUMEN
Although Mn-based oxygen evolution clusters in photosystem II show efficient activity in water oxidation, the catalytic performance of artificial Mn-based electrocatalysts is far from satisfactory, which is probably due to the undesirable atomic structure and electronic arrangement of their Mn ions. Aiming to systematically study the performance of two-dimensional (2D) catalysts, we designed and synthesized a series of nanosheets, including NiMn LDH and Ni-birnessite and their morphology-retained annealing products NiMnOx-L and NiMnOx-B, respectively. We comprehensively compared the OER performance of these 2D electrocatalysts in conjunction with the information on their crystalline phases, electronic conductivity, electrochemical surface area and oxidation states of their transition metal ions. It was found that the annealing-converted NiMnOx exhibited 3- and 5-times higher concentrations of catalytically active Mn(iii) than the corresponding NiMn LDH and Ni-birnessite precursors. Moreover, the layered atomic structure was beneficial for the charge transfer, leading to faster reaction kinetics. Among the nanosheets tested, NiMnOx-B showed the best alkaline OER performance with the lowest overpotential and the smallest Tafel slope because it not only retained the layered atomic structure and the 2D nanosheet morphology of the Ni-birnessite precursor, but also benefitted from the decreased interlayer distance and more Mn(iii) species. This work sheds light on the design of effective non-noble metal-based electrocatalysts towards water oxidation for hydrogen production.
RESUMEN
Low-cost and efficient electrocatalysts with high dispersion of active sites and high conductivity are of high importance for oxygen evolution reaction (OER). Herein, we use amorphous mesoporous fumed silica (MFS) as a skeleton material to disperse Ni2+ and Fe3+ through a simple impregnation strategy. The MFS is in situ etched away during the OER process in 1 M KOH to prepare a stable mesoporous Ni-Fe electrocatalyst. The high specific surface area and abundant surface silanol groups in the mesoporous fumed silica afford rich anchor sites for fixing metal atoms via strong chemical metal-oxygen interactions. Raman and XPS investigations reveal that Ni2+ formed covalent bonds with surface Si-OH groups, and Fe3+ inserted into the framework of fumed silica forming Fe-O-Si bonds. The mesoporous Ni-Fe catalysts offer high charge transfer abilities in the OER process. When loaded on nickel foam, the optimal 2Ni1Fe-MFS catalyst exhibits an overpotential of 270 mV at 10 mA cm-2 and a Tafel slope of 41 mV dec-1. Notably, 2Ni1Fe-MFS shows a turnover frequency value of 0.155 s-1 at an overpotential of 300 mV, which is 80 and 190 times higher than that of the state-of-the-art IrO2 and RuO2 catalysts. Furthermore, 2Ni1Fe-MFS exhibits 100% faradaic efficiency, large electrochemically active surface area, and good long-term durability, confirming its outstanding OER performance. Such high OER efficiency can be ascribed to the synergistic effect of high surface area, dense metal active sites and interfacial conductive path. This work provides a promising strategy to develop simple, cost-effective, and highly efficient porous Ni-Fe based catalysts for OER.
RESUMEN
Manipulating pore hierarchy in porous materials is an attractive, yet difficult challenge in crystalline zeolites. Here, we report core-shell MFI zeolites having trimodal mesopores with size gradually decreasing from the surface to the core, synthesized through a one-pot approach via controlled orthogonal self-assembly. The novel spatially resolved mesopore structures are ascribed to the nanoscale phase separation between mutually coupled interactions of organosilane supramolecular assembly and zeolite framework ordering. The highly hierarchical zeolite architecture with tapered mesopore distribution allowed for spatially resolved adsorption of florescent molecules, improved catalytic performance in condensation reactions, and an enhanced nanoreactor for coupling reactions due to alleviated diffusion limitations. The successful synthesis of fine-tuned zeolites with larger mesopores gradually subdivided into smaller mesopores (hierarchy-type I) may open up possibilities for emergent new porous structures exhibiting a higher degree of hierarchies that are currently inaccessible to many crystalline oxide or related materials.
RESUMEN
Photodynamic therapy (PDT) is an alternative strategy for treating pancreatic cancer (PC) in clinics. However, the therapeutic efficacy is generally suppressed by inadequate oxygen supply in the hypoxic tumor microenvironment. Herein, hierarchical zeolite nanocarriers with hydrophilic mesoporous nanostructures and excellent biodegradability are synthesized via a one-pot wet chemical method. By co-loading with catalase and methylene blue (MB), a new type of oxygen self-sufficient PDT platform, a zeolite-catalase-MB nanocapsule (ZCM nanocapsule), is developed. After precision implantation of the ZCM nanocapsule into the tumor area under the real-time ultrasound (US) imaging guidance, the nanocapsule with 90% relative activity of equivalent free catalase enzyme efficiently modulates the tumor hypoxia and enhances the intratumoral US contrast by sustained decomposition of endogenous H2O2 and in situ production of O2 gas bubbles. Meanwhile, the MB loading in hierarchical zeolite matrices prevents the rapid leaching of the photosensitizer in tumor tissue, achieving a good sustained photosensitizer release effect. Based on the synchronous mechanisms, upon near-infrared laser irradiation, the local PC cells are completely killed, and no therapy-induced toxicity and recurrence are observed. This highly biocompatible and biodegradable hierarchical nanozeolite would further facilitate the development of catalase-based catalytic nanomedicine for enhancing chemotherapy, radiotherapy and combination therapy.
Asunto(s)
Catalasa/administración & dosificación , Nanocápsulas , Oxígeno , Neoplasias Pancreáticas/tratamiento farmacológico , Fotoquimioterapia , Zeolitas , Animales , Línea Celular Tumoral , Células HEK293 , Humanos , Peróxido de Hidrógeno , Hipoxia , Azul de Metileno/administración & dosificación , Ratones Desnudos , Neoplasias Pancreáticas/diagnóstico por imagen , Microambiente Tumoral , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Shape control in metal-organic frameworks still remains a challenge. We propose a strategy based on the capping agent modulator method to control the shape of ZIF-8 nanocrystals. This approach requires the use of a surfactant, cetyltrimethylammonium bromide (CTAB), and a second capping agent, tris(hydroxymethyl)aminomethane (TRIS), to obtain ZIF-8 nanocrystals with morphology control in aqueous media. Semiempirical computational simulations suggest that both shape-inducing agents adsorb onto different surface facets of ZIF-8, thereby slowing down their crystal growth rates. While CTAB molecules preferentially adsorb onto the {100} facets, leading to ZIF-8 particles with cubic morphology, TRIS preferentially stabilizes the {111} facets, inducing the formation of octahedral crystals. Interestingly, the presence of both capping agents leads to nanocrystals with irregular shapes and higher index facets, such as hexapods and burr puzzles. Additionally, the combination of ZIF-8 nanocrystals with other materials is expected to impart additional properties due to the hybrid nature of the resulting nanocomposites. In the present case, the presence of CTAB and TRIS molecules as capping agents facilitates the synthesis of metal nanoparticle@ZIF-8 nanocomposites, due to synergistic effects which could be of use in a number of applications such as catalysis, gas sensing and storage.
RESUMEN
Catalytic oxidation of carbon monoxide (CO) is of great importance in many different fields of industry. Until now it still remains challenging to use non-noble metal based catalysts to oxidize CO at low temperature. Herein, we report a new class of nanoporous, uniform, and transition metal-doped cerium (IV) oxide (ceria, CeO2) microsphere for CO oxidation catalysis. The porous and uniform microsphere is generated by sacrificed polymer template. Transition-metals, like Cu, Co, Ni, Mn and Fe, were doped into CeO2 microspheres. The combination of hierarchical structure and metal doping afford superior catalytic activities of the doped ceria microspheres, which could pave a new way to advanced non-precious metal based catalysts for CO oxidation.
RESUMEN
Some key parameters of supports such as porosity, pore shape and size are of great importance for fabrication and performance of zeolite membranes. In this study, we fabricated millimetre-thick, self-standing electrospun ceramic nanofibre mats and employed them as a novel support for zeolite membranes. The nanofibre mats were prepared by electrospinning a halloysite nanotubes/polyvinyl pyrrolidone composite followed by a programmed sintering process. The interwoven nanofibre mats possess up to 80% porosity, narrow pore size distribution, low pore tortuosity and highly interconnected pore structure. Compared with the commercial α-Al2O3 supports prepared by powder compaction and sintering, the halloysite nanotube-based mats (HNMs) show higher flux, better adsorption of zeolite seeds, adhesion of zeolite membranes and lower Al leaching. Four types of zeolite membranes supported on HNMs have been successfully synthesized with either in situ crystallization or a secondary growth method, demonstrating good universality of HNMs for supporting zeolite membranes.
RESUMEN
Oral squamous cell carcinoma (OSCC) is usually preceded by the oral premalignant lesions, mainly oral leukoplakia (OLK) after repeated insults of carcinogens, tobacco. B(a)P and DMBA are key carcinogens in tobacco smoke. In the present study, for the first time we established the cancerous cell line OSCC-BD induced by B(a)P/DMBA mixture and transformed from dysplastic oral leukoplakia cell line DOK. Cell morphology, proliferation ability, migration ability, colony formation, and tumorigenicity were studied and confirmed the malignant characteristics of OSCC-BD cells. We further identified the differential proteins between DOK and OSCC-BD cells by stable isotope dimethyl labeling based quantitative proteomic method, which showed 18 proteins up-regulated and 16 proteins down-regulated with RSD < 8%. Differential proteins are mainly related to cell cycle, cell proliferation, DNA replication, RNA splicing and apoptosis. Abberant binding function, catalysis activity and transportor activity of differential proteins might contribute to the malignant transformation of OLK. Of the 34 identified differential proteins with RSD < 8%, 13 novel cancer-related proteins were reported in the present study. This study might provide a new insight into the mechanism of OLK malignant transformation and the potent biomarkers for early diagnosis, meanwhile further facilitate the application of the quantification proteomics to carcinogenesis research.
Asunto(s)
Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Transformación Celular Neoplásica , Leucoplasia Bucal/fisiopatología , Neoplasias de la Boca/metabolismo , Proteínas de Neoplasias/metabolismo , 9,10-Dimetil-1,2-benzantraceno/toxicidad , Apoptosis , Benzo(a)pireno/toxicidad , Biomarcadores de Tumor , Carcinógenos/toxicidad , Carcinoma de Células Escamosas/inducido químicamente , Carcinoma de Células Escamosas/fisiopatología , Proliferación Celular , Regulación de la Expresión Génica , Humanos , Neoplasias de la Boca/inducido químicamente , Neoplasias de la Boca/fisiopatología , Proteínas de Neoplasias/análisis , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/fisiología , ProteómicaRESUMEN
Chronic exposure to ultraviolet (UV) irradiation is believed to be the major cause of skin damage that results in premature aging of the skin, so called photoaging, characterized by increases in skin thickness, formation of wrinkles, and loss of skin elasticity. UV induces damage to skin mainly by oxidative stress and collagen degradation. In this study, we examined the photo-protective effect of hydroxysafflor yellow A (HSYA), a major active chemical component isolated from Carthamus tinctorius L., by topical application on the skin of mice. Exposure of the dorsal depilated skin of mice to UV radiation four times a week for 10 weeks induced epidermal hyperplasia, elastin accumulation, collagen degradation, etc. HSYA at the doses of 50, 100, and 200 µg/mouse was topically applied immediately following each UV exposure. The effects of HSYA were evaluated by a series of tests, including macroscopic and histopathological evaluation of skin, pinch test, and redox homeostasis of skin homogenates. Results showed that the UV-induced skin damage was significantly improved after HSYA treatment, especially at doses of 100 and 200 µg/mouse. This protective effect is possibly related to the anti-oxidative property of HSYA and mediated by promoting endogenous collagen synthesis. This is the first study providing preclinical evidence for the protective effect of HSYA against photoaging.