Via a comprehensive time-resolved operando-DRIFTS study of the evolutions of various surface species on Au/CeO2 catalysts with Au particle sizes ranging from 1.7 ± 0.6 to 3.7 ± 0.9 nm during CO ...oxidation at room temperature, we have successfully demonstrated size-dependent reaction pathways and their contributions to the catalytic activity. The types and concentrations of chemisorbed CO(a), carbonate, bicarbonate, and formate species formed upon CO adsorption, their intrinsic oxidation/decomposition reactivity, and roles in CO oxidation vary with the size of the supported Au particles. The intrinsic oxidation reactivity of CO(a) does not depend much on the Au particle size, whereas the intrinsic decomposition reactivity of carbonate, bicarbonate, and formate species strongly depend on the Au particle size and are facilitated over Au/CeO2 catalysts with large Au particles. These results greatly advance the fundamental understanding of the size effect of Au/CeO2 catalysts for low-temperature CO oxidation.
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► Efficient CuO/MnO2 catalysts have been developed for CO oxidation. ► CuO/MnO2 catalysts with CuO loading of 1–40% exhibit almost the same catalytic performance toward CO oxidation. ...► The CuO–MnO2 interface is the active site for CO oxidation in CuO/MnO2 catalysts. ► CO oxidation over CuO/MnO2 catalysts likely follows the interfacial reaction mechanism.
A series of CuO/MnO2 catalysts with different CuO loadings were synthesized by the incipient wetness impregnation method. The catalysts were characterized by N2 adsorption–desorption isotherms, powder X-ray diffraction, X-ray photoelectron spectroscopy, H2-temperature programmed reduction, CO-temperature programmed reduction and scanning electron microscope. The CuO/MnO2 catalysts with CuO loading of 1–40% exhibit almost the same catalytic performance toward CO oxidation while those with higher CuO loadings exhibit a much poorer catalytic activity. The structural characterization results demonstrate that the CuO–MnO2 interface is the active site for CO oxidation in CuO/MnO2 catalysts and CO oxidation over CuO/MnO2 probably follows the interfacial reaction mechanism in which CO chemisorbed on CuO reacts with oxygen species on MnO2 at the CuO–MnO2 interface.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Pd nanocrystals were prepared by the reduction of a H2PdCl4 aqueous solution with C2H4 in the presence of different amounts of poly(N-vinyl-2-pyrrolidone) (PVP). Their average size decreases ...monotonically as the PVP monomer/Pd molar ratio increases up to 1.0 and then does not vary much at higher PVP monomer/Pd molar ratios. Infrared spectroscopy and X-ray photoelectron spectroscopy results reveal the interesting size-dependent interaction of PVP molecules with Pd nanocrystals. For fine Pd nanocrystals capped with a large number of PVP molecules, each PVP molecule chemisorbs with its oxygen atom in the ring; for large Pd nanocrystals capped by a small number of PVP molecules, each PVP molecule chemisorbs with both the oxygen atom and nitrogen atom in the ring, which obviously affects the structure of chemisorbed PVP molecules and even results in the breaking of involved C–N bonds of some chemisorbed PVP molecules. Charge transfer always occurs from a chemisorbed PVP ligand to Pd nanocrystals. These results provide novel insights into the PVP–metal nanocrystal interaction, which are of great importance in the fundamental understanding of surface-mediated properties of PVP-capped metal nanocrystals.
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We have investigated the geometric and electronic structures of the cerium oxide (CeO2)-titanium dioxide (TiO2) mixed oxides with various Ce/TiO2 weight ratios prepared by the sol-gel method in ...detail by means of X-ray diffraction (XRD), high-resolution X-ray photoelectron spectroscopy (XPS), Raman spectroscopy excited by 325 and 514.5nm lasers, and scanning electron microscope (SEM). Existence of cerium effectively inhibits the phase transition of TiO2 from the anatase phase to the rutile phase. XRD peaks of TiO2 anatase attenuate continuously with the increasing amount of CeO2 in the mixed oxide, but the XRD peaks of cubic CeO2 appear only after the weight ratio of Ce/TiO2 reaches 0.50. The average crystalline sizes of TiO2 anatase and cubic CeO2 in CeO2-TiO2 mixed oxides are smaller than those in the corresponding individual TiO2 anatase and cubic CeO2. Raman spectroscopy excited by the 514.5nm laser detects CeO2 after the weight ratio of Ce/TiO2 reaches 0.70 whereas Raman spectroscopy excited by the 325nm laser detects CeO2 after the weight ratio of Ce/TiO2 reaches 0.90. XPS results demonstrate that Ti exists in the form of Ti4+ in the CeO2-TiO2 mixed oxide. Ce is completely in the form of Ce3+ in the mixed oxides with a 0.05 weight ratio of Ce/TiO2. With the increasing weight ratio of Ce/TiO2, Ce4+ dominates. On basis of these results, we proposed that CeO2 initially nucleates at the defects (oxygen vacancies) within TiO2 anatase, forming an interface bridged with oxygen between CeO2 and TiO2 anatase. At the interface, Ce species cannot substitute Ti4+ in the lattice of TiO2 anatase whereas Ti4+ can substitute Ce4+ in the lattice of cubic CeO2. The decreasing concentration of oxygen vacancies, the Ti-O-Ce interface, and the decreasing average crystalline size of TiO2 anatase act to inhibit the phase transformation of TiO2 anatase. With the increasing amounts of CeO2, the CeO2 clusters continuously grow and form cubic CeO2 nanocrystals. Spectroscopic results strongly demonstrate that the surface region of CeO2-TiO2 mixed oxide is enriched with TiO2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Gliomas are the most common and fatal malignant type of tumor of the central nervous system. RNA post-transcriptional modifications, as a frontier and hotspot in the field of epigenetics, have ...attracted increased attention in recent years. Among such modifications, methylation is most abundant, and encompasses N6-methyladenosine (m6A), 5-methylcytosine (m5C), N1 methyladenosine (m1A), and 7-methylguanosine (m7G) methylation.
RNA-sequencing data from healthy tissue and low-grade glioma samples were downloaded from of The Cancer Genome Atlas database along with clinical information and mutation data from glioblastoma tumor samples. Forty-nine m6A/m5C/m1A/m7G-related genes were identified and an m6A/m5C/m1A/m7G-lncRNA signature of co-expressed long non-coding RNAs selected. Least absolute shrinkage and selection operator Cox regression analysis was used to identify 12 m6A/m5C/m1A/m7G-related lncRNAs associated with the prognostic characteristics of glioma and their correlation with immune function and drug sensitivity analyzed. Furthermore, the Chinese Glioma Genome Atlas dataset was used for model validation.
A total of 12 m6A/m5C/m1A/m7G-related genes (AL080276.2, AC092111.1, SOX21-AS1, DNAJC9-AS1, AC025171.1, AL356019.2, AC017104.1, AC099850.3, UNC5B-AS1, AC006064.2, AC010319.4, and AC016822.1) were used to construct a survival and prognosis model, which had good independent prediction ability for patients with glioma. Patients were divided into low and high m6A/m5C/m1A/m7G-LS groups, the latter of which had poor prognosis. In addition, the m6A/m5C/m1A/m7G-LS enabled improved interpretation of the results of enrichment analysis, as well as informing immunotherapy response and drug sensitivity of patients with glioma in different subgroups.
In this study we constructed an m6A/m5C/m1A/m7G-LS and established a nomogram model, which can accurately predict the prognosis of patients with glioma and provides direction toward promising immunotherapy strategies for the future.
A series of Fe
2
O
3
–CeO
2
composite catalysts were synthesized by coprecipitation and characterized by X-ray diffraction (XRD), BET surface area measurement, Raman spectroscopy, and X-ray ...photoelectron spectroscopy (XPS). Their catalytic activities in CO oxidation were also tested. The Fe
2
O
3
–CeO
2
composites with an Fe molar percentage below 0.3 form solid solutions with the CeO
2
cubic fluorite structure, in which the doped Fe
3+
initially substitutes Ce
4+
in fluorite cubic CeO
2
, but then mostly locate in the interstitial sites after a critical concentration of doped Fe
3+
. With an Fe molar percentage between 0.3 and 0.95, the Fe
2
O
3
–CeO
2
composites are mixed oxides of the cubic fluorite CeO
2
solid solution and the hematite Fe
2
O
3
. XPS results indicate that CeO
2
is enriched in the surface region of Fe
2
O
3
–CeO
2
composites. The Fe
2
O
3
–CeO
2
composites have much higher catalytic activities in CO oxidation than the individual pure CeO
2
and Fe
2
O
3
, and the Fe
0.1
Ce
0.9
composite shows the best catalytic performance. The structure-activity relation of the Fe
2
O
3
–CeO
2
composites in CO oxidation is discussed in terms of the formation of solid solution and surface oxygen vacancies. Our results demonstrate a proportional relation between the catalytic activity of cubic CeO
2
-like solid solutions and their density of oxygen vacancies, which directly proves the formation of oxygen vacancies as the key step in CO oxidation over oxide catalysts.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The morphological evolution of uniform Cu2O nanocrystals with different morphologies in a weak acetic acid solution (pH = 3.5) has been studied for cubic, octahedral, rhombic dodecahedral, {100} ...truncated octahedral, and {110} truncated octahedral nanocrystals. Cu2O nanocrystals undergo oxidative dissolution in weak acid solution, but their morphological changes depend on the exposed crystal planes. We found that the stability of Cu2O crystal planes in weak acid solution follows the order of {100} ≫ {111} > {110} and determines how the morphology of Cu2O nanocrystals evolves. The stable {100} crystal planes remain, and new {100} facets form at the expense of the less stable {111} and {110} crystal planes on the surface of Cu2O nanocrystals. Density functional theory calculations reveal that the Cu−O bond on Cu2O(100) surface has the shortest bond length. These results clearly exemplify that the morphology of inorganic crystals will evolve with the change of local chemical environment, shedding light on fundamentally understanding the morphological evolution of natural minerals and providing novel insights into the geomimetic synthesis of inorganic materials in the laboratory.
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We have successfully prepared visible-light-active mesoporous N-doped TiO2 (N-TiO2) photocatalysts by the precipitation of titanyl oxalate complex (TiO(C2O4)22−) by ammonium hydroxide at a low ...temperature followed by calcination at different temperatures. The structures of N-TiO2 photocatalysts have been characterized in detail by means of powder X-ray diffraction, N2 adsorption−desorption isotherms, infrared spectroscopy, diffuse reflectance UV−vis spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscope. The calcination process of the catalyst precursor was also studied by means of temperature-programmed reaction spectroscopy. N-TiO2 photocatalysts exhibit comparable UV-light activity and visible-light activity in the photodegradation of methyl orange. The doped N species locates at the interstitial sites in TiO2, which leads to the band gap narrowing of TiO2. A novel and interesting result is that N-doped TiO2 calcined at 400 °C (N-TiO2-400) has Brönsted acid sites arising from covalently bonded dicarboxyl groups, which greatly enhances the adsorption capacity for methyl orange. The N-TiO2-400 catalyst is a promising adsorption−photodegradation integration catalyst; meanwhile, it is also a promising acid catalysis−photocatalysis bifunctional catalyst.
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Purpose: This study investigated the clinical manifestations, surgical method, and treatment outcomes of patients with pituitary apoplexy and evaluated the safety and effectiveness of the endoscopic ...endonasal transsphenoidal approach in the treatment of pituitary adenomas. Patients and methods: In this retrospective study, were analyzed the data of patients with symptomatic pituitary apoplexy who received surgical treatment by endoscopic endonasal transsphenoidal approach from January 2017 to June 2020 at the Department of Neurosurgery of the First Affiliated Hospital of Bengbu Medical College. Patients were followed up through outpatient visits and telephone interviews. Results: Data for 24 patients including 13 males and 11 females with an average age of 46.46 years were analyzed. Headache (83.33%) and visual disturbances (75.00%) were the most common preoperative manifestations. In the 24 patients, 21 (87.50%) tumors were completely removed and 3 (12.50%) were partly removed. Intractable headache improved in all patients over a mean follow-up time of 25.16 months, and postoperative improvement in visual acuity was achieved in 17 of 18 patients (94.44%) with vision defects. Four patients (16.67%) experienced transient urinary collapse after the operation. No intracranial infection, carotid artery injury, or death occurred. Conclusion: The endoscopic endonasal transsphenoidal approach is a safe and effective method for the treatment of pituitary apoplexy.
Abstract
Background
Craniopharyngioma (CP) is a slow-growing, benign tumor of the central nervous system located within the sellar and suprasellar regions. The tumor may extend from the suprasellar ...region to other areas. CPs are generally believed to originate from squamous remnants of an incompletely involuted craniopharyngeal duct that also develops from Rathke’s pouch. Primary parasellar craniopharyngioma is a relatively rare tumor, and nasal endoscopy, computed tomography, and enhanced magnetic resonance imaging can be applied to better evaluate the invasiveness and characteristics of these tumors.
Case presentation
We report a case of right parasellar craniopharyngioma in a 49-year-old female patient with a 10-day history of dizziness and blurred vision. Preoperative imaging examination revealed right parasellar space-occupying lesions, and the patient underwent transnasal neuroendoscopic resection of the right parasellar space-occupying lesion. The postoperative pathological result confirmed craniopharyngioma.
Conclusions
Primary ectopic parasellar craniopharyngioma is a relatively rare tumor, and preoperative imaging examination can assist in the evaluation of tumor characteristics. However, the final diagnosis continues to depend on the histopathological results.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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