Microelectrode study of pore size, ion size, and solvent effects on the charge/discharge behavior of microporous carbons for electrical double-layer capacitors

The capacitive behavior of TiC-derived carbon powders in two different electrolytes, NEt4BF4 in acetonitrile AN and NEt4BF4 in propylene carbonate PC, was studied using the cavity microelectrode CME technique. Comparisons of the cyclic voltammograms recorded at 10–1000 mV/s enabled correlation between adsorbed ion sizes and pore sizes, which is important for understanding the electrochemical capacitive behavior of carbon electrodes for electrical double-layer capacitor applications. The CME technique also allows a fast selection of carbon electrodes with matching pore sizes different sizes are needed for the negative and positive electrodes for the respective electrolyte system. Comparison of electrochemical capacitive behavior of the same salt, NEt4BF4, in different solvents, PC and AN, has shown that different pore sizes are required for different solvents, because only partial desolvation of ions occurs during the double-layer charging. Squeezing partially solvated ions into subnanometer pores, which are close to the desolvated ion size, may lead to distortion of the shape of cyclic voltammograms

In Situ NMR Spectroscopy of Supercapacitors: Insight into the Charge Storage Mechanism

Electrochemical capacitors, commonly known as supercapacitors, are important energy storage devices with high power capabilities and long cycle lives. Here we report the development and application of in situ nuclear magnetic resonance(NMR) methodologies to study changes at the electrode−electrolyte interface in working devices as they charge and discharge. For a supercapacitor comprising activated carbon electrodes and an organic electrolyte, NMR experiments carried out at different charge states allow quantification of the number of charge storing species and show that there are at least two distinct charge storage regimes. At cell voltages below 0.75 V, electrolyte anions are increasingly desorbed from the carbon micropores at the negative electrode, while at the positive electrode there is little change in the number of anions that are adsorbed as the voltage is increased. However, above a cell voltage of 0.75 V, dramatic increases in the amount of adsorbed anions in the positive electrode are observed while anions continue to be desorbed at the negative electrode. NMR experiments with simultaneous cyclic voltammetry show that supercapacitor charging causes marked changes to the local environments of charge storing species, with periodic changes of their chemical shift observed. NMR calculations on a model carbon fragment show that the addition and removal of electrons from a delocalized system should lead to considerable increases in the nucleus-independent chemical shift of nearby species, in agreement with our experimental observations

Immune biomarkers of response to immune-checkpoint inhibitors in head and neck squamous cell carcinoma

Anti-programmed cell death protein 1 (PD-1) agents have become the standard of care for platinum-refractory recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) and are currently being evaluated in various disease settings. However, despite the gain in overall survival seen in some of the clinical trials, the majority of patients display primary resistance and do not benefit from these agents. Taking into consideration the potentially severe immune-related toxicities and their high cost, the search for predictive biomarkers of response is crucial. Besides Programmed death ligand-1 (PD-L1) expression, other biomarkers such as immune infiltration, tumor mutational burden or immune-gene expression profiling have been explored, but none of them has been validated in this disease. Among these, the microbiota has recently garnered tremendous interest since it has proven to influence the efficacy of PD-1 blockade in some tumor types. With the accumulating evidence on the effect of the microbiota in HNSCC tumorigenesis and progression, the study of its potential role as a predictive immune biomarker is warranted. This review examines the available evidence on emerging immune predictive biomarkers of response to anti-PD-1/PD-L1 therapy in HNSCC, introducing the microbiota and its potential use as a predictive immune biomarker in this disease

Optimizing the generation of hematopoietic progenitor cells from pluripotent stem cells in dynamic suspension culture

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Improved breeding and seed production of climbing perch (<em>Anabas testudineus</em>) in controlled tanks and cage systems

The climbing perch (Anabas testudineus) is a valuable fish species with significant potential for aquaculture. However, a low survival rate was observed at its early development stages, requiring an optimized protocol for sustainable aquaculture production. This paper presents an improved breeding and seed production technology for climbing perch. Mature climbing perch were induced to spawn using salmon gonadotropin-releasing hormone analog (sGnRHa) at a dose of 30 µg/kg-1 body weight of the breeder. The female broodfish spawn 9–10 hours after hormone injection. Developmental stages were defined based on the morphological features of the embryos from the first cleavage to the hatching stage. The first cleavage began at approximately 18–20 minutes after fertilization. Newly hatched larvae were observed within 18–20 h at 30°C, having an average larval size of 0.389±0.042 mm (total length). Successful breeding entails a selection of suitable algal species, an optimal aquaculture environment, regular feeding rates, consistent monitoring of larval development, and effective management of water quality. Survival rates from the larval stage to fry were achieved at 84.69% and 77.60%, respectively, while the survival rate to the fingerlings stage was 72.51%. Therefore, by implementing an optimized protocol, aquaculture practitioners can maximize the production potential of climbing perch while ensuring sustainable cultivation practices. The findings from this research contribute to the advancement of climbing perch aquaculture by providing valuable insights for the successful cultivation and increased economic profitability of A. testudineus species in hatchery productions

SEOM clinical guidelines for the treatment of head and neck cancer (2020)

Head and neck cancers (HNC) are defined as malignant tumours located in the upper aerodigestive tract and represents 5% of oncologic cases in adults in Spain. More than 90% of these tumours have squamous histology. In an effort to incorporate evidence obtained since 2017 publication, the Spanish Society of Medical Oncology (SEOM) presents an update of the squamous cell HNC diagnosis and treatment guideline. Most relevant diagnostic and therapeutic changes from the last guideline have been updated: introduction of sentinel node biopsy in early oral/oropharyngeal cancer treated with surgery, concomitant radiotherapy with weekly cisplatin 40 mg/m2 in the adjuvant setting, new approaches for HPV-related oropharyngeal cancer and new treatments with immune-checkpoint inhibitors in recurrent/metastatic disease

Nanoscale Surface and Bulk Electronic Properties of Ti3C2Tx MXene Unraveled by Multimodal X Ray Spectromicroscopy

2D layered materials, such as transition metal carbides or nitrides, known as MXenes, offer an ideal platform to investigate charge transfer processes in confined environment, relevant for energy conversion and storage applications. Their rich surface chemistry plays an essential role in the pseudocapacitive behavior of MXenes. However, the local distribution of surface functional groups over single flakes and within few or multilayered flakes remains unclear. In this work, scanning X ray microscopy SXM is introduced with simultaneous transmission and electron yield detection, enabling multimodal nanoscale chemical imaging with bulk and surface sensitivity, respectively, of individual MXene flakes. The Ti chemical bonding environment is found to significantly vary between few layered hydrofluoric acid etched Ti 3 C 2 T x MXenes and multilayered molten salt MS etched Ti 3 C 2 T x MXenes. Postmortem analysis of MS etched Ti3 C 2 T x electrodes cycled in a Li ion battery further illustrates that simultaneous bulk and surface chemical imaging using SXM offers a method well adapted to the characterization of the electrode electrolyte interactions at the nanoscal

Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon

Electrochemical capacitors, also called supercapacitors, store energy in two closely spaced layers with opposing charges, and are used to power hybrid electric vehicles, portable electronic equipment and other devices¹. By offering fast charging and discharging rates, and the ability to sustain millions of ²⁻⁵, electrochemical capacitors bridge the gap between batteries, which offer high energy densities but are slow, and conventional electrolytic capacitors, which are fast but have low energy densities. Here, we demonstrate microsupercapacitors with powers per volume that are comparable to electrolytic capacitors, capacitances that are four orders of magnitude higher, and energies per volume that are an order of magnitude higher. We also measured discharge rates of up to 200 V s⁻¹, which is three orders of magnitude higher than conventional supercapacitors. The microsupercapacitors are produced by the electrophoretic deposition of a several micrometre-thick layer of nanostructured carbon onions⁶‚⁷ with diameters of 6-7 nm. Integration of these nanoparticles in a microdevice with a high surface-to-volume ratio, without the use of organic binders and polymer separators, improves performance because of the ease with which ions can access the active material. Increasing the energy density and discharge rates of supercapacitors will enable them to compete with batteries and conventional electrolytic capacitors in a number of applications

Capacitance of Ti3C2Tx MXene in ionic liquid electrolyte

Ti3C2Tx MXene, a two-dimensional (2D) early transition metal carbide, has shown an extremely high volumetric capacitance in aqueous electrolytes, but in a narrow voltage window (less than 1.23 V). The utilization of MXene materials in ionic liquid electrolytes with a large voltage window has never been addressed. Here, we report the preparation of the Ti3C2Tx MXene ionogel film by vacuum filtration for use as supercapacitor electrodes operating in 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI) neat ionic liquid electrolyte. Due to the disordered structure of the Ti3C2Tx hydrogel film and a stable spacing after vacuum drying, achieved through ionic liquid electrolyte immersion of the Ti3C2Tx hydrogel film, the Ti3C2Tx surface became accessible to EMI+ and TFSI− ions. A capacitance of 70 F g−1 together with a large voltage window of 3 V was obtained at a scan rate of 20 mV s−1 in neat EMI-TFSI electrolyte. The electrochemical signature indicates a capacitive behavior even at a high scan rate (500 mV s−1) and a high power performance. This work opens up the possibilities of using MXene materials with various ionic liquid electrolytes