Table_1_Case report: Rare case of multinodular and vacuolar neuronal tumors in the cerebellum.DOCX

Multinodular and vacuolar neuronal tumor (MVNT) is a rare and benign neuroepithelial tumor. Most reports describe tumors located in the cerebral hemisphere. A literature review found that 15 cases were located in the posterior cranial fossa, but all lacked pathological evidence. In this case, a patient sought medical attention due to insomnia and irritability. Neuroepithelial tumors were found in the imaging, and the patient underwent radiation therapy. Three years later, malignant tumors were found upon imaging examination. After surgical resection and pathological testing, MVNT occurring in the cerebellum was diagnosed. MVNT is rare in the cerebellum, and direct imaging diagnosis becomes difficult after treatment. Therefore, our report of this case helps to further accurate understanding of the imaging, pathological, and molecular genetic changes occurring before and after MVNT treatment, and will improve the accuracy of pre-treatment diagnosis and reduce the likelihood of overtreatment.</p

Table_2_Case report: Rare case of multinodular and vacuolar neuronal tumors in the cerebellum.DOCX

Multinodular and vacuolar neuronal tumor (MVNT) is a rare and benign neuroepithelial tumor. Most reports describe tumors located in the cerebral hemisphere. A literature review found that 15 cases were located in the posterior cranial fossa, but all lacked pathological evidence. In this case, a patient sought medical attention due to insomnia and irritability. Neuroepithelial tumors were found in the imaging, and the patient underwent radiation therapy. Three years later, malignant tumors were found upon imaging examination. After surgical resection and pathological testing, MVNT occurring in the cerebellum was diagnosed. MVNT is rare in the cerebellum, and direct imaging diagnosis becomes difficult after treatment. Therefore, our report of this case helps to further accurate understanding of the imaging, pathological, and molecular genetic changes occurring before and after MVNT treatment, and will improve the accuracy of pre-treatment diagnosis and reduce the likelihood of overtreatment.</p

Table_3_Case report: Rare case of multinodular and vacuolar neuronal tumors in the cerebellum.DOCX

Multinodular and vacuolar neuronal tumor (MVNT) is a rare and benign neuroepithelial tumor. Most reports describe tumors located in the cerebral hemisphere. A literature review found that 15 cases were located in the posterior cranial fossa, but all lacked pathological evidence. In this case, a patient sought medical attention due to insomnia and irritability. Neuroepithelial tumors were found in the imaging, and the patient underwent radiation therapy. Three years later, malignant tumors were found upon imaging examination. After surgical resection and pathological testing, MVNT occurring in the cerebellum was diagnosed. MVNT is rare in the cerebellum, and direct imaging diagnosis becomes difficult after treatment. Therefore, our report of this case helps to further accurate understanding of the imaging, pathological, and molecular genetic changes occurring before and after MVNT treatment, and will improve the accuracy of pre-treatment diagnosis and reduce the likelihood of overtreatment.</p

Insights into Li⁺, Na⁺, and K⁺ Intercalation in Lepidocrocite-Type Layered TiO₂ Structures

A lamellar lepidocrocite-type titanate structure with ∼25% Ti⁴⁺ vacancies was recently synthesized, and it showed potential for use as an electrode in rechargeable lithium-ion batteries. In addition to lithium, we explore this material’s ability to accommodate other monovalent ions with greater natural abundance (e.g., sodium and potassium) in order to develop lower-cost alternatives to lithium-ion batteries constructed from more widely available elements. Galvanostatic discharge/charge curves for the lepidocrocite material indicate that increasing the ionic radius of the monovalent ion results in a deteriorating performance of the electrode. Using first-principles electronic structure calculations, we identify the relaxed geometries of the structure while varying the placement of the ion in the structure. We then use these geometries to compute the energy of formations. Additionally, we determine that all ions are favorable in the structure, but interlayer positions are preferred compared to vacancy positions. We also conclude that the exchange between the interlayer and vacancy positions is a process that involves the interaction between interlayer water and surface hydroxyl groups next to the titanate layer. We observe a cooperative effect between structural water and OH groups to assist alkali ions to move from the interlayer to the vacancy site. Thus, the as-synthesized lepidocrocite serves as a prototypical structure to investigate the migration mechanism of ions within a confined space along with the interaction between water molecules and the titanate framework

Spectroelectrochemical Probing of the Strong Interaction between Platinum Nanoparticles and Graphitic Domains of Carbon

This study focuses on clarifying the strong interaction existing between extended graphitic domains of ordered carbonaceous materials such as multiwalled carbon nanotubes and platinum nanoparticles. This interaction results from the heterogeneous nucleation of platinum nanoparticles onto the carbon support. The metal clusters are chemically synthesized by using the carbonyl route. Two different carbon supports are used namely, homemade multiwalled carbon nanotubes, MWCNT-m, and classical Vulcan XC-72. Physicochemical properties of these materials are described by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The effect of the strong interaction on the electronic properties of platinum nanoparticles is electrochemically probed by means of CO stripping experiments coupled with <i>in situ</i> Fourier transform infrared spectroscopy (FTIR). Density functional theory (DFT) is used to evaluate changes to the electronic structure of a platinum cluster interacting with a graphite substrate and their effects on CO adsorption on the cluster. Results are correlated with structural and electronic properties of platinum nanoparticles. The stability of Pt/carbon catalysts under electrochemical potential cycling is correlated with the properties of carbon substrates

Layered Lepidocrocite Type Structure Isolated by Revisiting the Sol–Gel Chemistry of Anatase TiO₂: A New Anode Material for Batteries

Searches for new electrode materials for batteries must take into account financial and environmental costs to be useful in practical devices. The sol–gel chemistry has been widely used to design and implement new concepts for the emergence of advanced materials such as hydride organic–inorganic composites. Here, we show that the simple reaction system including titanium alkoxide and water can be used to stabilize a new class of electrode materials. By investigating the crystallization path of anatase TiO₂, an X-ray amorphous intermediate phase has been identified whose local structure probed by the pair distribution function, ¹H solid-state NMR and density functional theory (DFT) calculations, consists of a layered type structure as found in the lepidocrocite. This phase presents the following general formula Ti_2–<i>x</i>□_<i>x</i>O_{4–4<i>x</i>}(OH)_4<i>x</i>·<i>n</i>H₂O (<i>x</i> ∼ 0.5) where the substitution of oxide by hydroxide anions leads to the formation of titanium vacancies (□) and H₂O molecules are located in interlayers. Solid-state ¹H NMR has enabled us to characterize three main hydroxide environments, Ti□–OH, Ti₂□₂–OH, and Ti₃□–OH, and layered H₂O molecules. The electrochemical properties of this phase were investigated  vs lithium and were shown to be very promising with reversible capacities of around 200 mAh·g^–1 and an operating voltage of 1.55 V. We further showed that the lithium intercalation proceeds via a solid-solution mechanism. ⁷Li solid-state NMR and DFT calculations allowed us to identify lithium host sites that are located at the titanium vacancies and interlayer space with lithium being solvated by structural water molecules. The easy fabrication, the absence of lithium, easier recycling, and the encouraging properties make this class of materials very attractive for competitive electrodes for batteries. We thus demonstrate that revisiting an “old” chemistry with advanced characterization tools allows one to discover new materials of technological relevance

High Substitution Rate in TiO₂ Anatase Nanoparticles with Cationic Vacancies for Fast Lithium Storage

Doping is generally used to tune and enhance the properties of metal oxides. However, their chemical composition cannot be readily modified beyond low dopant amounts without disrupting the crystalline atomic structure. In the case of anatase TiO₂, we introduce a new solution-based chemical route allowing the composition to be significantly modified, substituting the divalent O^2– anions by monovalent F^– and OH^– anions resulting in the formation of cationic Ti⁴⁺ vacancies (□) whose concentration can be controlled by the reaction temperature. The resulting polyanionic anatase has the general composition Ti_{1–<i>x</i>–<i>y</i>}□_{<i>x</i>+<i>y</i>}O_{2–4(<i>x</i>+<i>y</i>)}F_4<i>x</i>(OH)_4<i>y</i>, reaching vacancy concentrations of up to 22%, i.e., Ti_0.78□_0.22O_1.12F_0.4(OH)_0.48. Solid-state ¹⁹F NMR spectroscopy reveals that fluoride ions can accommodate up to three different environments, depending on Ti and vacancies (i.e. Ti₃-F, Ti₂□₁-F, and Ti₁□₂-F), with a preferential location close to vacancies. DFT calculations further confirm the fluoride/vacancy ordering. When its characteristics were evaluated as an electrode for reversible Li-ion storage, the material shows a modified lithium reaction mechanism, which has been rationalized by the occurrence of cationic vacancies acting as additional lithium hosting sites within the anatase framework. Finally, the material shows a fast discharging/charging behavior, compared to TiO₂, highlighting the benefits of the structural modifications and paving the way for the design of advanced electrode materials, based on a defect mediated mechanism