29 research outputs found
CT-based radiomics for predicting radio-chemotherapy response and overall survival in nonsurgical esophageal carcinoma
BackgroundTo predict treatment response and 2 years overall survival (OS) of radio-chemotherapy in patients with esophageal cancer (EC) by radiomics based on the computed tomography (CT) images.MethodsThis study retrospectively collected 171 nonsurgical EC patients treated with radio-chemotherapy from Jan 2010 to Jan 2019. 80 patients were randomly divided into training (n=64) and validation (n=16) cohorts to predict the radiochemotherapy response. The models predicting treatment response were established by Lasso and logistic regression. A total of 156 patients were allocated into the training cohort (n=110), validation cohort (n=23) and test set (n=23) to predict 2-year OS. The Lasso Cox model and Cox proportional hazards model established the models predicting 2-year OS.ResultsTo predict the radiochemotherapy response, WFK as a radiomics feature, and clinical stages and clinical M stages (cM) as clinical features were selected to construct the clinical-radiomics model, achieving 0.78 and 0.75 AUC (area under the curve) in the training and validation sets, respectively. Furthermore, radiomics features called WFI and WGI combined with clinical features (smoking index, pathological types, cM) were the optimal predictors to predict 2-year OS. The AUC values of the clinical-radiomics model were 0.71 and 0.70 in the training set and validation set, respectively.ConclusionsThis study demonstrated that planning CT-based radiomics showed the predictability of the radiochemotherapy response and 2-year OS in nonsurgical esophageal carcinoma. The predictive results prior to treatment have the potential to assist physicians in choosing the optimal therapeutic strategy to prolong overall survival
Nitrogen, Phosphorus Co-Doped Graphite Felt as Highly Efficient Electrode for VO<sup>2+</sup>/VO<sub>2</sub><sup>+</sup> Reaction
All-vanadium redox flow batteries hold promise for the next-generation grid-level energy storage technology in the future. However, the low electrocatalytic activity of initial graphite felt constrains the development of VRFBs. Furthermore, the positive VO2+/VO2+ reaction involves complex multistep processes and more sluggish kinetics than negative V2+/V3+ reaction. Therefore, enhancing the kinetics of positive reaction is especially important. Heteroatom doping is one of the effective strategies for preparing carbon electrodes with high electrocatalytic activity and good stability. Here, a nitrogen, phosphorus co-doped graphite felt is prepared. Nitrogen introduces more negative charge into the carbon lattice due to the higher electronegativity, and more oxygen-containing functional groups will be introduced into the carbon lattice due to phosphorus-doped graphite felt. N, P co-doping provides more adsorption sites for vanadium ions. As a result, nitrogen, phosphorus co-doped graphite felt shows high electrochemical activity and good stability, and the corresponding VRFB presents a good voltage efficiency of 75% at a current density of 300 mA cm−2, which is 11% higher than the pristine graphite felt. During 100 charge/discharge cycles, the energy efficiency and voltage efficiency remain at 84% and 86% under the current density of 150 mA cm−2
Theoretical Investigation Of The Weak Interaction Between Graphene And Alcohol Solvents
The dispersion of graphene in five different alcohol solvents was investigated by evaluating the binding energy between graphene and alcohol molecules using DFT-D method. The calculation showed the most stable binding energy appeared at the distance of ∼3.5 Å between graphene and alcohol molecules and increased linearly as changing the alcohol from methanol to 1-pentanol. The weak interaction was further graphically illustrated using the reduced density gradient method. The theoretical study revealed alcohols with more carbon atoms could be a good starting point for screening suitable solvents for graphene dispersion
Progress of polymer chain structure regulation of alkaline anion-exchange membranes for fuel cells
Polyoxometalate-based electrolyte materials in redox flow batteries: Current trends and emerging opportunities
Redox flow batteries have received wide attention for electrochemical energy conversion and storage devices due to their specific advantage of uncoupled power and energy devices, and therefore potentially to reduce the capital costs of energy storage. Terrific structural features of polyoxometalates exhibit unique advantages in redox flow batteries, such as, stable chemical properties, multi-electron reaction, good redox reversibility, low permeability, etc, which furnishes a novel perspective for settling various problems of redox flow batteries. This was a comprehensive and critical review of this type of batteries, focusing mainly on the chemistry of polyoxometalate electrolyte materials and introducing a systematic classification. Finally, challenges and perspectives of polyoxometalate electrolyte materials and polyoxometalate redox flow batteries are discussed
Highly conductive quaternary ammonium-containing cross-linked poly (vinyl pyrrolidone) for high-temperature PEM fuel cells with high-performance
Poly(vinyl pyrrolidone) (PVP)-based high-temperature polymer electrolyte membranes (HT-PEMs) doped with phosphoric acid (PA) present an attractive prospect for high-temperature fuel cell. However, its proton conductivities and mechanical properties are inversely dependent on PVP content in membranes. Herein, chloromethyl-polysulfone is used as a polymeric crosslinker to fabricate cross-linked PVP. The effects of chloromethylation degree of polysulfone on PVP cross-linking degree, free volume and other parameters are studied. The quaternary amine groups introduced by cross-linking reaction enhances PA adsorption and retention capacity of membrane. The increased molar free volume created by polymeric crosslinker can accommodate more PA storage and reduce the polymer main chain plasticization. Thus, the mechanical properties of membranes are maintained. When compared to uncross-linked C-PVP-0/PA, the cross-linked C-PVP-13.7%/PA exhibits improved mechanical strength with increasement of 140% (4.5 MPa) and enhanced proton conductivity with increasement of 119% (120.0 mS cm(-1)@160 & nbsp;C). Also, these superior characteristics allow a significantly enhanced H-2-O-2 fuel cell performance with the membrane of 724.9 mW cm(-2) @160 & nbsp;C, which has increasement of 50% in comparison with that of the C-PVP-0%/PA membrane, and excellent durability. These praiseworthy results suggest that the cross-linked membrane within moderately molar free volume is potential to act as HT-PEMs materials for real world applications
Highly conductive quaternary ammonium-containing cross-linked poly (vinyl pyrrolidone) for high-temperature PEM fuel cells with high-performance
Poly(vinyl pyrrolidone) (PVP)-based high-temperature polymer electrolyte membranes (HT-PEMs) doped with phosphoric acid (PA) present an attractive prospect for high-temperature fuel cell. However, its proton conductivities and mechanical properties are inversely dependent on PVP content in membranes. Herein, chloromethyl-polysulfone is used as a polymeric crosslinker to fabricate cross-linked PVP. The effects of chloromethylation degree of polysulfone on PVP cross-linking degree, free volume and other parameters are studied. The quaternary amine groups introduced by cross-linking reaction enhances PA adsorption and retention capacity of membrane. The increased molar free volume created by polymeric crosslinker can accommodate more PA storage and reduce the polymer main chain plasticization. Thus, the mechanical properties of membranes are maintained. When compared to uncross-linked C-PVP-0/PA, the cross-linked C-PVP-13.7%/PA exhibits improved mechanical strength with increasement of 140% (4.5 MPa) and enhanced proton conductivity with increasement of 119% (120.0 mS cm(-1)@160 & nbsp;C). Also, these superior characteristics allow a significantly enhanced H-2-O-2 fuel cell performance with the membrane of 724.9 mW cm(-2) @160 & nbsp;C, which has increasement of 50% in comparison with that of the C-PVP-0%/PA membrane, and excellent durability. These praiseworthy results suggest that the cross-linked membrane within moderately molar free volume is potential to act as HT-PEMs materials for real world applications
Advancement toward Polymer Electrolyte Membrane Fuel Cells at Elevated Temperatures
Elevation of operational temperatures of polymer electrolyte membrane fuel cells (PEMFCs) has been demonstrated with phosphoric acid-doped polybenzimidazole (PA/PBI) membranes. The technical perspective of the technology is simplified construction and operation with possible integration with, e.g., methanol reformers. Toward this target, significant efforts have been made to develop acid-base polymer membranes, inorganic proton conductors, and organic-inorganic composite materials. This report is devoted to updating the recent progress of the development particularly of acid-doped PBI, phosphate-based solid inorganic proton conductors, and their composite electrolytes. Long-term stability of PBI membranes has been well documented, however, at typical temperatures of 160°C. Inorganic proton-conducting materials, e.g., alkali metal dihydrogen phosphates, heteropolyacids, tetravalent metal pyrophosphates, and phosphosilicates, exhibit significant proton conductivity at temperatures of up to 300°C but have so far found limited applications in the form of thin films. Composite membranes of PBI and phosphates, particularly in situ formed phosphosilicates in the polymer matrix, showed exceptionally stable conductivity at temperatures well above 200°C. Fuel cell tests at up to 260°C are reported operational with good tolerance of up to 16% CO in hydrogen, fast kinetics for direct methanol oxidation, and feasibility of nonprecious metal catalysts. The prospect and future exploration of new proton conductors based on phosphate immobilization and fuel cell technologies at temperatures above 200°C are discussed
Double-layered yolk-shell microspheres with NiCo2S4-Ni9S8-C hetero-interfaces as advanced battery-type electrode for hybrid supercapacitors
It requires excellent conductivity, rapid diffusion of electrolyte and high active specific area of active materials to achieve efficient supercapacitor. Herein, the novel NiCo2S4-Ni9S8-C double-layered yolk-shell microspheres (NiCo2S4Ni9S8-C DYMs) were synthesized by using bimetallic metal-organic framework (MOF) as self-template. The microspheres are composed of numerous tiny heterogeneous NiCo2S4-Ni9S8 nanoparticles (similar to 10 nm in size) decorated in amorphous carbon. As expected, the sample exhibits high specific capacity of 293.6 mAh g(-1) at 1 A g(-1), excellent rate capacity (81.1% from 1 A g(-1) to 20 A g(-1)) and good cycling stability (capacity retention of 87.3% over 5000 cycles). The hybrid supercapacitor assembled by NiCo2S4-Ni9S8-C DYMs and grapheme hydrogel, shows an energy density of 51 Wh kg(-1) at a power density of 1399.4 W kg(-1) and even can retain 32.5 Wh kg(-1) at 8004.4 W kg(-1). The density functional theory (DFT) calculation show the hetero-interfaces of NiCo2S4-Ni9S8 can optimize the electronic distribution, coupled with the excellent electroconductivity of dispersed carbon within microspheres, which boost the electrochemical performance. This work provides an approach to fabricate heterogeneous microspheres by MOF route for developing advanced battery-type electrode materials