The influence of solvents and salts on the properties of high-voltage cathode materials

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license.-- et al.Lithium - ion batteries play an increasingly important role in the battery industry and they have become the dominant source of energy in the recent years, especially for portable electronic devices due to their high gravimetric energy density. This article examines the influence of mixtures of solvents with different combinations of lithium salts on the stability of two types of high-voltage cathode materials: LiNi0.5Mn1.5O4 and LiCr0.1Ni0.4Mn1.5O4 produced by a solid phase reaction. These materials were combined with several different electrolytes, cycled at various loads and higher temperature. Various combinations of solvents ethylene carbonate (EC), dimethyl carbonate (DMC) and Tetrahydrothiophene 1.1-dioxide (Sulfolane) were used for these measurements. Salts LiPF6, LiNO3 and LiTFSI were used. The influence of solvents and salts on the properties of high-voltage cathode materials was tested by cycling at different current loads and by cycling at high temperature. It was found out, by LSV analysis, that the addition of Sulfolane increases the stability of electrolyte. The addition of chromium to the cathode material LiNi0.5Mn1.5O4 causes increasing of capacity and stability at high temperature. The combination of the cathode material LiCr0.1Ni0.4Mn1.5O4 with the electrolyte 1.5 M LiPF6 EC:DMC:Sulfolane 1:2:1 w/w/w leads to increased stability in comparison with other electrolytes.This research work has been carried out in the Centre for Research and Utilization of Renewable Energy (CVVOZE). Authors gratefully acknowledge financial support from the Ministry of Education, Youth and Sports of the Czech Republic under NPU I programme (project No. LO1210).Peer Reviewe

Unilateral hippocampal sparing during whole brain radiotherapy for multiple brain metastases: narrative and critical review

BackgroundThe landscape of brain metastases radiotherapy is evolving, with a shift away from whole-brain radiotherapy (WBRT) toward targeted stereotactic approaches aimed at preserving neurocognitive functions and maintaining overall quality of life. For patients with multiple metastases, especially in cases where targeted radiotherapy is no longer feasible due to widespread dissemination, the concept of hippocampal sparing radiotherapy (HA_WBRT) gains prominence.MethodsIn this narrative review we explore the role of the hippocampi in memory formation and the implications of their postradiotherapy lateral damage. We also consider the potential advantages of selectively sparing one hippocampus during whole-brain radiotherapy (WBRT). Additionally, by systematic evaluation of relevant papers published on PubMed database over last 20 years, we provide a comprehensive overview of the various changes that can occur in the left or right hippocampus as a consequence of radiotherapy.ResultsWhile it is important to note that various neurocognitive functions are interconnected throughout the brain, we can discern certain specialized roles of the hippocampi. The left hippocampus appears to play a predominant role in verbal memory, whereas the right hippocampus is associated more with visuospatial memory. Additionally, the anterior part of the hippocampus is more involved in episodic memory and emotional processing, while the posterior part is primarily responsible for spatial memory and pattern separation. Notably, a substantial body of evidence demonstrates a significant correlation between post-radiotherapy changes in the left hippocampus and subsequent cognitive decline in patients.ConclusionIn the context of individualized palliative radiotherapy, sparing the unilateral (specifically, the left, which is dominant in most individuals) hippocampus could expand the repertoire of strategies available for adapted WBRT in cases involving multiple brain metastases where stereotactic radiotherapy is not a viable option. Prospective ongoing studies assessing various memory-sparing radiotherapy techniques will define new standard of radiotherapy care of patients with multiple brain metastases

Human Papillomavirus-Related Non-Metastatic Oropharyngeal Carcinoma: Current Local Treatment Options and Future Perspectives

Over the last two decades, human papillomavirus (HPV) has caused a new pandemic of cancer in many urban areas across the world. The new entity, HPV-associated oropharyngeal squamous cell carcinoma (OPSCC), has been at the center of scientific attention ever since, not only due to its distinct biological behavior, but also because of its significantly better prognosis than observed in its HPV-negative counterpart. The very good treatment outcomes of the disease after primary therapy (minimally-invasive surgery, radiation therapy with or without chemotherapy) resulted in the creation of a separate staging system, reflecting this excellent prognosis. A substantial proportion of newly diagnosed HPV-driven OPSCC is diagnosed in stage I or II, where long-term survival is observed worldwide. Deintensification of the primary therapeutic methods, aiming at a reduction of long-term toxicity in survivors, has emerged, and the quality of life of the patient after treatment has become a key-point in many clinical trials. Current treatment recommendations for the treatment of HPV-driven OPSCC do not differ significantly from HPV-negative OPSCC; however, the results of randomized trials are eagerly awaited and deemed necessary, in order to include deintensification into standard clinical practice

The Diagnostic Ability of Follow-Up Imaging Biomarkers after Treatment of Glioblastoma in the Temozolomide Era: Implications from Proton MR Spectroscopy and Apparent Diffusion Coefficient Mapping

Objective. To prospectively determine institutional cut-off values of apparent diffusion coefficients (ADCs) and concentration of tissue metabolites measured by MR spectroscopy (MRS) for early differentiation between glioblastoma (GBM) relapse and treatment-related changes after standard treatment. Materials and Methods. Twenty-four GBM patients who received gross total resection and standard adjuvant therapy underwent MRI examination focusing on the enhancing region suspected of tumor recurrence. ADC maps, concentrations of N-acetylaspartate, choline, creatine, lipids, and lactate, and metabolite ratios were determined. Final diagnosis as determined by biopsy or follow-up imaging was correlated to the results of advanced MRI findings. Results. Eighteen (75%) and 6 (25%) patients developed tumor recurrence and pseudoprogression, respectively. Mean time to radiographic progression from the end of chemoradiotherapy was 5.8 ± 5.6 months. Significant differences in ADC and MRS data were observed between those with progression and pseudoprogression. Recurrence was characterized by N-acetylaspartate ≤ 1.5 mM, choline/N-acetylaspartate ≥ 1.4 (sensitivity 100%, specificity 91.7%), N-acetylaspartate/creatine ≤ 0.7, and ADC ≤ 1300 × 10−6 mm2/s (sensitivity 100%, specificity 100%). Conclusion. Institutional validation of cut-off values obtained from advanced MRI methods is warranted not only for diagnosis of GBM recurrence, but also as enrollment criteria in salvage clinical trials and for reporting of outcomes of initial treatment

Electrochemical Characterization of High-Performance Sulfur Composites as Cathodes for Li-S Batteries with Application in Automotive Industry

Lithium-sulfur batteries are based on principle of conversion and their properties are very promising for their high theoretical energy density and low cost. However, current electrodes and materials used in Li-S batteries suffer from irreversible electrochemical reaction of polysulfides, low conductivity and stability. Here we summarize preparation and characterization of sulfur samples with polymer additive polypyrrole/polyethylene glycol to improve conductivity and stability of Li-S batteries. We also discuss very simple preparation technique of polypyrrole suitable also for industrial production. The electrochemical properties of sulfur-carbon-polypyrrole (S-C-PPy) composites were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge measurements. Properties of resulting composite samples (especially conductivity) are strongly affected by the preparation technique and conditions. Insulating polymer PEG was used to improve the polymeric structure and mechanical robustness of PPy chain. Porosity of composite sample increase with increasing amount of PPy. On the other hand conductivity is reduced with increased porosity. Electrochemical measurements confirmed that addition of PEG can improve conductivity also in the presence of higher amounts of PPy in the sample. PPy-PEG composite polymer decrease particle to particle contact resistance. Co-polymer coating consisting of PPy-PEG significantly decreases the charge transfer resistance of prepared samples what was confirmed by impedance measurements

FMISO-Based Adaptive Radiotherapy in Head and Neck Cancer

Concurrent chemoradiotherapy represents one of the most used strategies in the curative treatment of patients with head and neck (HNC) cancer. Locoregional failure is the predominant recurrence pattern. Tumor hypoxia belongs to the main cause of treatment failure. Positron emission tomography (PET) using hypoxia radiotracers has been studied extensively and has proven its feasibility and reproducibility to detect tumor hypoxia. A number of studies confirmed that the uptake of FMISO in the recurrent region is significantly higher than that in the non-recurrent region. The escalation of dose to hypoxic tumors may improve outcomes. The technical feasibility of optimizing radiotherapeutic plans has been well documented. To define the hypoxic tumour volume, there are two main approaches: dose painting by contour (DPBC) or by number (DPBN) based on PET images. Despite amazing technological advances, precision in target coverage, and surrounding tissue sparring, radiation oncology is still not considered a targeted treatment if the “one dose fits all” approach is used. Using FMISO and other hypoxia tracers may be an important step for individualizing radiation treatment and together with future radiomic principles and a possible genome-based adjusting dose, will move radiation oncology into the precise and personalized era

Recurrent Nasopharyngeal Cancer: Critical Review of Local Treatment Options Including Recommendations during the COVID-19 Pandemic

Recurrent nasopharyngeal carcinoma represents an extremely challenging therapeutic situation. Given the vulnerability of the already pretreated neurological structures surrounding the nasopharynx, any potential salvage retreatment option bears a significant risk of severe complications that result in high treatment-related morbidity, quality of life deterioration, and even mortality. Yet, with careful patient selection, long-term survival may be achieved after local retreatment in a subgroup of patients with local or regional relapse of nasopharyngeal cancer. Early detection of the recurrence represents the key to therapeutic success, and in the case of early stage disease, several curative treatment options can be offered to the patient, albeit with minimal support in prospective clinical data. In this article, an up-to-date review of published evidence on modern surgical and radiation therapy treatment options is summarized, including currently recommended treatment modifications of both therapeutic approaches during the coronavirus disease 2019 pandemic