A novel activating agent for the production of highly microporous carbons with textural properties that match those of superactivated carbons prepared by KOH activation, i.e. BET surface areas of ...2600–3000 m2 g−1, pore volumes of ∼1.3–1.6 cm3 g−1 and pore size distributions in the supermicropore-small mesopore (<3 nm) region, is studied. It consists of a mixture of melamine and potassium oxalate, a substance which is less corrosive than KOH, imposing less technical restrictions. Additional advantages of this activating agent are that the morphology of the particles is not altered and, importantly, the product yield is almost double that of KOH activation. The advantageous textural characteristics of the produced materials are combined with a relatively good electronic conductivity of ∼2–3 S cm−1. When tested as supercapacitor electrodes using conventional electrolytes such as H2SO4 and TEABF4/AN, and less conventional ones such as EMImTFSI/AN, these carbons match the performance of benchmark KOH activated carbons and surpass that of commercial activated carbons specifically designed for supercapacitor applications.
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Supercapacitor technology is an extremely timely area of research with fierce international competition to develop cost-effective, environmentally friendlier EC electrode materials that have real ...world application. Herein, nitrogen-doped carbons with large specific surface area, optimized micropore structure and surface chemistry have been prepared by means of an environmentally sound hydrothermal carbonization process using defatted soybean (i.e., Soybean meal), a widely available and cost-effective protein-rich biomass, as precursor followed by a chemical activation step. When tested as supercapacitor electrodes in aqueous electrolytes (i.e. H2SO4 and Li2SO4), they demonstrate excellent capacitive performance and robustness, with high values of specific capacitance in both gravimetric (250-260 and 176 F g(-1) in H2SO4 and Li2SO4 respectively) and volumetric (150-210 and 102 F cm(-3) in H2SO4 and Li2SO4 respectively) units, and remarkable rate capability (>60% capacitance retention at 20 A g(-1) in both media). Interestingly, when Li2SO4 is used, the voltage window is extended up to 1.7 V (in contrast to 1.1 V in H2SO4). Thus, the amount of energy stored is increased by 50% compared to H2SO4 electrolyte, enabling this environmentally sound Li2SO4-based supercapacitor to deliver ~12 Wh kg(-1) at a high power density of ~2 kW kg(-1).
Treatment approaches for relapsed ovarian cancer have evolved over the past decade from a calendar-based decision tree to a patient-oriented biologically driven algorithm. Nowadays, platinum-based ...chemotherapy should be offered to all patients with a reasonable chance of responding to this therapy. The treatment-free interval for platinum is only one of many factors affecting patients' eligibility for platinum re-treatment. Bevacizumab increases the response to chemotherapy irrespective of the cytotoxic regimen and can be valuable in patients with an urgent need for symptom relief (e.g. pleural effusion, ascites). For patients with recurrent high-grade ovarian cancer, which responds to platinum-based treatment, maintenance therapy with a poly(ADP-ribose) polymerase inhibitor can be offered, regardless of the BRCA mutation status. Here we review contemporary decision-making processes in the systemic treatment of relapsed ovarian cancer.
•Platinum-based chemotherapy remains the most active treatment for ovarian cancer.•Platinum should not be withheld after response to last platinum and a treatment-free interval of <6 months.•We propose to move beyond the definition of platinum resistance to a therapy-oriented definition of platinum eligibility.•Platinum-non-eligible ovarian cancer patients are those with progression on or immediately after their last platinum.
Lithium‐ion batteries and related battery concepts show an expansion and shrinkage (“breathing”) of the electrodes during cell cycling. The dimensional changes of an individual electrode or a ...complete cell can be continuously measured by electrochemical dilatometry (ECD). The obtained data provides information on the electrode/cell reaction itself but can be also used to study side reactions or other relevant aspects, e.g., how the breathing is influenced by the electrode binder and porosity. The method spans over a wide measurement range and allows the determination of macroscopic as well as nanoscopic changes. It has also been applied to supercapacitors. The method has been developed already in the 1970s but recent advancements and the availability of commercial setups have led to an increasing interest in ECD. At the same time, there is no “best practice” on how to evaluate the data and several pitfalls exist that can complicate the comparison of literature data. This review highlights the recent development and future trends of ECD and its use in battery and supercapacitor research. A practical guide on how to evaluate the data is provided along with a discussion on various factors that influence the measurement results.
Electrochemical dilatometry is a powerful operando technique to measure the thickness change in an electrochemical device during cycling. Several studies have been published in recent years, investigating batteries and supercapacitors. This review presents selected examples from literature, a guideline on how to evaluate dilatometry data, and gives information on which effects have an influence on the data.
Abstract
For Li‐ion and Na‐ion batteries, the intercalation behavior of graphite anodes is quite different. While Li‐ions intercalate, Na‐ions only co‐intercalate with solvent molecules from the ...electrolyte solution leading to ternary graphite intercalation compound (t‐GIC) formation along with an expansion of the graphite interlayer spacing to 1.2 nm. This large interlayer spacing represents a micropore with parallel slit geometry. Little is known about t‐GIC formation, but it is commonly believed that throughout the reaction the ion is accompanied by either a full or partial solvation shell. Here, it is elucidated for the first time, using two independent methods – mass measurements and electrochemical impedance spectroscopy – supplemented by operando microscopy, entropymetry and simulations, that the storage mechanism is far more complex. A new model for the electrochemical solvent co‐intercalation process is proposed: As soon as solvated ions enter, the graphite structure is flooded with free solvents, which are subsequently replaced by solvated ions. Close to full sodiation, few free solvents remain and structural rearrangement take place to reach the full storage capacity. Thus, t‐GICs represent a unique case of switchable microporous systems and hence appear as a bridge between ion storage in the bulk phase and in micropores, i.e., between batteries and supercapacitors.
This manuscript reports the consensus statements regarding recurrent ovarian cancer (ROC), reached at the fifth Ovarian Cancer Consensus Conference (OCCC), which was held in Tokyo, Japan, in November ...2015. Three important questions were identified: (i) What are the subgroups for clinical trials in ROC? The historical definition of using platinum-free interval (PFI) to categorise patients as having platinum-sensitive/resistant disease was replaced by therapy-free interval (TFI). TFI can be broken down into TFIp (PFI), TFInp (non-PFI) and TFIb (biological agent-free interval). Additional criteria to consider include histology, BRCA mutation status, number/type of previous therapies, outcome of prior surgery and patient reported symptoms. (ii) What are the control arms for clinical trials in ROC? When platinum is considered the best option, the control arm should be a platinum-based therapy with or without an anti-angiogenic agent or a poly (ADP-ribose) polymerase (PARP) inhibitor. If platinum is not considered the best option, the control arm could include a non-platinum drug, either as single agent or in combination. (iii) What are the endpoints for clinical trials in ROC? Overall survival (OS) is the preferred endpoint for patient cohorts with an expected median OS < or = 12 months. Progression-free survival (PFS) is an alternative, and it is the preferred endpoint when the expected median OS is > 12 months. However, PFS alone should not be the only endpoint and must be supported by additional endpoints including pre-defined patient reported outcomes (PROs), time to second subsequent therapy (TSST), or time until definitive deterioration of quality of life (TUDD).
A new automatic method for discontinuity traces mapping and sampling on a rock mass digital model is described in this work. The implemented procedure allows one to automatically identify ...discontinuity traces on a Digital Surface Model: traces are detected directly as surface breaklines, by means of maximum and minimum principal curvature values of the vertices that constitute the model surface. Color influence and user errors, that usually characterize the trace mapping on images, are eliminated. Also trace sampling procedures based on circular windows and circular scanlines have been implemented: they are used to infer trace data and to calculate values of mean trace length, expected discontinuity diameter and intensity of rock discontinuities. The method is tested on a case study: results obtained applying the automatic procedure on the DSM of a rock face are compared to those obtained performing a manual sampling on the orthophotograph of the same rock face.
► A new method for discontinuity traces mapping and sampling on a rock mass model. ► Automatic identification of discontinuity traces to estimate degree of fracturing. ► Quantitative evaluation of rock mass quality based on photogrammetry/laser scanner. ► Method to quickly analyze huge amount of trace data. ► This is part of a research ongoing at University of Parma from 10 years.
In situ (operando) electrochemical dilatometry (ECD) provides information on the expansion/shrinkage of an electrode during cell cycling. It is shown that the ECD signal can be used as descriptor to ...characterize the charge storage behavior of lithium and sodium ions in hard carbon electrodes. It is found that sodium storage in hard carbons occurs by a three‐step mechanism, namely I) insertion, II) pore filling, and III) plating. Step III can be seen from a sudden increase in electrode thickness for potentials below around 36 mV versus Na+/Na and is assigned to plating on the hard carbon surface. Interestingly, this last step is absent in the case of lithium which demonstrates that the storage behavior between both alkali metals is different. The plating mechanism is also supported by reference experiments in which bulk plating is enforced. Bulk plating on hard carbon electrodes can be detected more easily for sodium compared to lithium. It is also found that the type of binder strongly influences the dilatometry results. A comparison between the binders sodium salt of carboxymethyl cellulose and poly(vinylidene difluoride) shows that the use of the former leads to notably smaller first electrode expansion as well as a higher initial Coulomb efficiency.
Plating only for sodium: The storage mechanism of sodium and lithium ions in hard carbon is investigated by monitoring the change of the electrode thickness during charging and discharging. For lithium ions, a two‐step mechanism is found, whereas for sodium ions, a three‐step mechanism with a plating process as the last mechanism is found.
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