batterydata/paper-abstracts huggingface dataset:
The human fetus is exposed to a variety of environmental agents and drugs which cross the placenta and can induce DNA damage. Micronucleus (MN) determination is a suitable and sensitive method for measuring DNA damage and since umbilical cord blood is obtained without any risk for the newborn, we measured the frequency of MN in cells from cord blood in four groups of healthy newborns (NB): 35 NB whose mothers lived in two urban cities (groups I and II); 16 NB from an agricultural area (group III); and 15 NB of mothers with high-risk pregnancy (group IV). MN were also evaluated in the mothers of NB from group I (n =17) and group III (n =14). Acetylcholinesterase (AChE) concentration was measured in groups I and III. The average frequency of binucleated cells with MN was 3.7±1.4 in 1000 cells in mothers and 1±0.9 in 1000 cells in NB from urban areas; and 4.5±2.4 in1000 cells in mothers and 2±1.5 in 1000 cells in NB from the agricultural area. The correlation between the frequency of MN in mothers and NB was significant (r =0.61, p <0.01). AChE levels of samples obtained both from group III mothers and from newborns were similar to those of group I. The Wilcoxon's rank-sum test was applied to measure differences in MN frequency; NB of group I were used as control group. A significant (p <0.01) higher frequency of MN (4±2) was found only in lymphocytes from NB from high-risk pregnancies. Data indicate that MN evaluation in umbilical cord samples might be useful in the identification of transplacental mutagens.
Increases in the total volume of basal ganglia structures have been reported in schizophrenia. However, patterns of basal ganglia shape change, which can reveal localized changes in substructure volumes, have not been investigated. In this study, the total volume and shape of several basal ganglia structures were compared in subjects with and without schizophrenia. T1-weighted magnetic resonance scans were collected in 54 schizophrenia and 70 comparison subjects. High-dimensional (large-deformation) brain mapping was used to assess the shape and volume of several basal ganglia structures. The relationships of shape and volume measures with psychopathology, cognition and motor function were also assessed. Left and right volumes of the caudate and putamen, as well as the right globus pallidus volume, were significantly increased in subjects with schizophrenia as compared to comparison subjects after total brain volume was included as a covariate. Significant differences in shape accompanied these volume changes in the caudate, putamen and globus pallidus, after their total volumes were included as covariates. There were few significant correlations between volume or shape measures and either cognitive function or clinical symptoms, other than a positive correlation between an attention/vigilance cognitive dimension and the volume of the caudate and putamen, and a negative correlation between nucleus accumbens volume and delusions. In conclusion, basal ganglia volumes relative to total brain volume were larger in schizophrenia subjects than healthy comparison subjects. Specific patterns of shape change accompanied these volume differences.
A comprehensive assessment of both selective (focused attention, divided attention) and intensive (alertness and vigilance) attentional processes was performed on 106 patients with closed head injury using a computerised battery for the evaluation of attention. All patients were tested at least five months after their accident. A high percentage of patients were pathological in tests mapping the selective components of attention while only a minority were impaired on tests mapping the intensive components of attention. Three different subgroups of patients with consistent performance patterns were evidenced. The psychometric characteristics of the battery and its possible clinical usefulness are discussed.
Aqueous electrolytes containing a very high concentration of salt are useful for improving the performance of aqueous rechargeable batteries. These electrolytes, which contain a higher mole concentration of salt than that of water, have only a small amount of free water. Consequently, the electrochemical stability window of various electrodes in such electrolytes is wider than the predicted thermodynamic value of 1.23 V. Moreover, the formation of a solid electrolyte interphase on the negative electrode surface also contributes to the larger electrochemical stability window. In this work, we found that a redox wave corresponding to the electrochemical reduction of bis(trifluoromethylsulfonyl)imide anions in a highly concentrated (21 molal) solution of lithium bis(trifluoromethylsulfonyl)imide is barely observed when the potential range that the electrode is cycled is limited to between 0 and - 1.8 V.
This paper reviews the results of investigations into the electrochemical formation and properties of redox-active films formed from fullerenes and selected transition-metal complexes. These polymeric films are formed on the electrode surface during electroreduction of a solution containing a fullerene or a fullerene derivative and complexes of Pd(II), Pt(II), Rh(II) and Ir(I). The polymeric network is formed through covalent bonding between the transition-metal atoms (or complexes) and the fullerenes. Films containing C60 exhibit electrochemical activity in the negative potential range due to the reduction of the fullerene component. In this potential range, a decrease in the film resistance is also observed. In the case of the well-studied C60/Pt and C60/Pd films, the polymer formation process may also be accompanied by deposition of metal nanocrystals if a high ratio of metal complex to fullerene is used during film formation. The presence of this metallic phase in the film influences its morphology, structure, and electrochemical properties. Films formed from C60 with covalently bound electron-donating groups exhibit electrochemical activity in both negative and positive potential ranges. Since these systems exhibit both p- and n-doping properties, they can be called ‘double cables’. These fullerene/transition-metal films may have considerable potential for a number of applications. They can be used as charge storage materials for batteries and photovoltaic devices. The C60/Pd film can be also used as an electrochemical sensor. Films of C60/Pd and C60/Pt containing metallic palladium or platinum particles catalyze hydrogenation of olefins and acetylenes. Laser ablation of electrochemically formed C60/M and C70/M films (M =Pt or Ir) results in the fragmentation and formation of hetero-fullerenes such us [C59 M]+ and [C58 M]–. To cite this article: K. Winkler and A.L. Balch, C. R. Chimie 9 (2006) .
Radioluminescence (RL) characterization of the yttrium stannate (Y2Sn2O7) phosphors doped with 1mol% Tb, Eu and Dy was carried out and significant electronic transitions corresponding to doped rare earth ions were observed. It was seen that all parts of these rare earth ions are included in the phosphor material in their trivalent state. The RL measurement indicates that the series of the emission-state 5D4→7F6, 5D4→7F4, 5D4→7F3, corresponding to the characteristic 4f→4f intra-configuration forbidden transitions of Tb3+are appeared and that main emission peak occurs at about 542nm. There are in fact multiple emission lines at each of these due to the crystal field splitting of the ground state of the emitting ions. Eu-doped Y2Sn2O7 sample displayed intense and predominant emission peaks located at 580−650nm corresponding to the 5D0→7Fj (j=l, 2, 3 and 4) transitions. Red emission coming from the hypersensitive Dy doped phosphor presented luminescence emissions with dominating transitions at 4F9/2→6Hj (j=9/2, 11/2, 13/2 and 15/2). The sharp emission properties show that the Y2Sn2O7 is a suitable host for rare-earth ion doped phosphor material.
In view of impending depletion of hydrocarbon fuel resources and their negative environmental impact, it is imperative to significantly increase the energy conversion efficiency of hydrocarbon-based power generation systems. The combination of a hydrocarbon decomposition reactor with a direct carbon and hydrogen fuel cells (FC) as a means for a significant increase in chemical-to-electrical energy conversion efficiency is discussed in this paper. The data on development and operation of a thermocatalytic hydrocarbon decomposition reactor and its coupling with a proton exchange membrane FC are presented. The analysis of the integrated power generating system including a hydrocarbon decomposition reactor, direct carbon and hydrogen FC using natural gas and propane as fuels is conducted. It was estimated that overall chemical-to-electrical energy conversion efficiency of the integrated system varied in the range of 49.4–82.5%, depending on the type of fuel and FC used, and CO2 emission per kWelh produced is less than half of that from conventional power generation sources.
3,6-Bis(2-thienyl)-N-ethylcarbazole (Th-ECz-Th) was obtained by using organometallic polycondensation mediated by organotransition metal complexes. The properties of electrochemically obtained polymer films from this monomer were characterized by simultaneous voltametric and in situ conductivity and electrochemical quartz microbalance techniques.
Activation is a common strategy to tailor microstructure of carbon materials. A new activation combined with heteroatom doping of carbon nanofibers is proposed to synthesize the N, S-doped carbon nanofibers (NSCNFs). After electrospinning and followed thermal treatment with thiourea, the diameter of the as-obtained NSCNFs decreases with much more abundant pore structure and functionalized with S-containing oxygen groups compared with that obtained without activation. The increased specific surface area and pore volume are beneficial to facilitate the Na+ diffusion and provide more active sites to increase adsorption capacitance and facilitate pseudo-capacitive reactions. Also, the S-containing oxygen groups contribute to pseudo-capacitance by faradaic reactions. As a result, capacitive behavior is boosted hence leading to a excellent rate capability and cycling stability. The flexible and freestanding NSCNFs film is directly used as anode for sodium-ion batteries (NIBs) and shows excellent rate capability with reversible capacity of 147 and 133 mA h g-1 at 10 and 30 A g−1, respectively. Remarkably, ultra-long cyclic life is also achieved with 90.8% capacity retention after 6000 cycles at 10 A g−1. Such electrochemical performance makes NSCNFs promising to be used in high power and durable NIBs. This activation strategy can also be expanded to functionalize other carbon materials.
In this study, voltage relaxation and impedance spectroscopy are introduced as in-operando methods for detecting lithium plating in commercial lithium-ion cells with graphitic anodes. Voltage relaxation is monitored subsequent to defined charge steps of variable amplitudes, charge throughputs, termination criteria and at different ambient temperatures yielding dependencies over a wide experimental parameter range. An adapted differential voltage analysis is presented to resolve the characteristic mixed potential evolving in case of plating. Impedance spectroscopy is applied in parallel to the relaxation phase to trace a possible alteration of the cell's impedance due to the concurrent depletion of reversibly deposited lithium. The introduced voltage differentials are shown to resolve the mixed potential with restrictions only for little charge throughputs. The comparison of voltage relaxation and already established stripping discharge reveals similarities of the underlying physicochemical processes and allows an estimate of the amount of deposited lithium in case of relaxation. In the evolution of the cell's impedance, a reversible shrinkage of the high frequency intersection resistance and the arc representing the anodic charge transfer process are identified as indicators towards plating. The presented methods solely rely on non-destructive measurement quantities and thus are fully suitable for the application in battery management systems.
Tungsten nitride supported on carbon black was prepared by temperature-programmed reaction (TPR) process and is proposed as a catalyst for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). The as-prepared catalyst was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The ORR activities of the catalyst were studied by electrochemical measurements and single cell tests, respectively. The results indicated that the tungsten nitride electrocatalyst exhibited attractive catalytic activity and stability for the ORR in PEMFCs. It is expected to be a promising cathode electrocatalyst for PEMFCs, especially for the comparatively high temperature proton exchange membrane fuel cells.
Gel polymer electrolyte (GPE) is able to solve the problem of poor cyclability for high voltage cathode such as LiNi0.5Mn1.5O4 at elevated temperature to some extent, but the traditional GPE based on poly(vinylidene fluoride-co-hexafluoropropene) [P(VdF-HFP)] cannot meet the requirements in terms of ionic conductivity and electrochemical stability. A novel GPE, based on polyethylene-supported poly(methyl methacrylate-butyl acrylate-acrylonitrile-styrene) (P(MMA-BA-AN-St)/PE), is reported in this paper. Physical characterizations indicate that the polymer membrane has a better pore structure and higher electrolyte uptake, leading to the improved ionic conductivity of 2.7×10−3 Scm−1 at 25°C for resulting GPE. Electrochemical characterizations show that the developed GPE exhibits lower interfacial resistance with lithium electrode and higher oxidative decomposition potential (up to 5.3V, vs. Li/Li+). In addition, LiNi0.5Mn1.5O4 cathode shows excellent cyclic stability under 55°C at 0.2C between 3V and 4.9V, in which the capacity retention of cathode combined with GPE is 81% after 150 cycles, compared with only 25% when using a liquid electrolyte.
Abstract Multifunctional materials, the most advanced and hi-tech engineering materials that can withstand mechanical loads and are featured with high thermal stability, fatigue resistance along with enhance chemical, and environmental resistance. Effective efforts have been made from past decades to design a substitute for existing metallic materials, in terms of weight, better performance, and cost effectiveness, by fabricating promising multifunctional hybrid polymer composites and hybrid nanocomposites. The multifunctional composites features characteristics novel and emerging applications ranging from catalytic, electrical, capacitors, batteries, hybrid ground vehicles, biomedical engineering, automotive, airplanes, space shuttles, remote sensing, environmental, energy conversion, and energy storage sectors. This chapter is intended to present a comprehensive review to explore the multifunctional materials and the properties of multifunctional hybrid composites. This chapter also offers a compilation regarding recent developments of hybrid composites and nanocomposites technology with major emphasis on its multifunctional applications, including some details of smart hybrid composites for potential future research.
Studies investigating the underlying pathophysiology are needed to help explain and understand the postoperative complications following Roux-en-Y gastric bypass (RYGB) surgery. This study aimed to characterize segmental gastrointestinal pH profiles, motility measures, and transit times in patients with RYGB.
The purpose was to determine if increasing serum 25(OH)D and calcium in postmenopausal women increased skeletal muscle size, strength, balance, and functional task performance while decreasing muscle fatigue. PCSA of the vastus lateralis increased and ascent of stairs time decreased after 6 months of increased serum 25(OH)D.
Zn batteries are attractive for energy storage due to their low cost and intrinsic safety. However, the low utilization of active materials results in unsatisfied capacities. Herein, Zn batteries based on nanostructured NiCo2O4 electrodes are developed. Through hydrothermal reactions, porous NiCo2O4 nanosheets, nanowires, and nanoplates are fabricated, which are in-situ grown on the surface of nickel foam substrates, facilitating the electron transport and electrochemical reactions. In particular, the battery with the nanowire electrode exhibits the largest discharge capacity of 230.1 mAh g−1, which accounts for 68.7% of the theoretical capacity of NiCo2O4. Based on the weights of NiCo2O4 and consumed Zn, the energy density of the battery is 301.3 Wh kg−1, higher than most of the reported Zn batteries. At a high current density of 8 A g−1, the capacity is still 164.25 mAh g−1, with the retention of 71.38%, which illustrates the high rate performance. Moreover, after 1000 discharge-charge cycles, the capacity retention is 63.23%, which reveals remarkable cycling stability. The results show that the NiCo2O4 nanowire electrode is attractive for Zn batteries with high capacity, energy density, rate performance, and cycling stability.
Aqueous supercapacitors usually suffer from low cell voltage (e.g. < 2 V) which furthermore limits the energy density. Herein, a new polyanionic molybdenophosphate anode that largely extends the cathodic stability of water and allows the assembly of a 2.7 V aqueous supercapacitor is reported. The molybdenophosphate material is deposited on 3D exfoliated graphite substrate via a facile electrochemical method. The electrode is further modified over an electrochemical activation process to introduce more oxygen vacancies and enlarge the lattice, which synergistically improve the charge transfer kinetics. The activated molybdenophosphate film exhibits remarkable pseudocapacitive performance: 556 F g−1 capacitance at 4.5 A g−1, ultralong cycle life of 100 000 cycles with no sign of capacitance decay, and low cutoff working potential of −1.5 V vs. SCE. Further investigations show that the charge storage process is associated with the cations in the electrolyte and the material undergoes multi-electron transfers within the functioning potential range. Coupling with a manganese oxide cathode, a 2.7 V aqueous supercapacitor is assembled and delivers a high energy density of 89.2 Wh kg−1 at the power density of 2733 W kg−1. The development of polyanion-based pseudocapacitive materials would open up new opportunities for the fabrication of high-performance energy storage systems.
We describe here an interesting approach towards electrochemical capacitors (ECCs) using graphite materials (as being used as conductive additives in rechargeable lithium-ion battery cathodes) in a Li+ containing organic electrolyte. The important result is that we achieved a voltage window of >4V, which is rather large, compared to the standard window of 2.5V for ordinary electric double layer capacitors (DLCs). The capacitor performance was evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge techniques. From charge–discharge studies of the symmetrical device (for instance, SFG6 carbon electrode), a specific capacitance of up to 14.5F/g was obtained at 16mA/cm2 current rate and at a low current rate (3mA/cm2), a higher value was obtained (63F/g). The specific capacitance decreased about 25% after 1000 cycles compared to the initial discharge process. The performances of these graphites are discussed in the light of both double layer capacitance (DLC) and pseudocapacitance (battery-like behavior). The high capacitance obtained was not only derived from the current-transient capacitive behavior but is also attributed to pseudocapacitance associated with some kind of faradaic reaction, which could probably occur due to Li+ intercalation/deintercalation reactions into graphitic layers of the carbons used. The ac impedance (electrochemical impedances spectroscopy, EIS) measurements were also carried out to evaluate the capacitor parameters such as equivalent series resistance (ESR) and frequency dependent capacitance (C freq). Cyclic voltammetry measurements were also performed to evaluate the cycling behavior of the carbon electrodes and the non-rectangular shaped voltammograms revealed the non-zero time constant [τ(RC)≠0] confirming that the current contains a transient as well as steady-state components.
The electrochemical behaviour of graphite positive electrode has been tested in the electrolyte solutions of 1moldm−3 LiPF6 dissolved in mixed solvents of sulfolane (SL) and ethylmethyl carbonate (EMC). The suppression of PF6 − anion intercalation into graphite by SL has been demonstrated. Moreover, the favourable effect of EMC on PF6 − insertion into graphite in SL-based solutions has been verified by ex situ XRD, ex situ Raman, and electrochemical tests. Furthermore, improved long-term cycling performance of graphite positive electrode has been obtained in solutions with suitable ratios of SL and EMC.
The insertion of lithium into electric anode in a lithium-ion battery results in local volume expansion and creates compressive stress in materials. To relax the compressive stress, structural damage including microcracking and local buckling can occur. Using the theory of diffusion-induced stress and the energy principle, analytical relations between the critical concentration of solute atoms and average damage size are established for the insertion-induced cracking and buckling in an elastic film. Numerical results show that surface cracking will prevail over local buckling in accord with experimental observation. For local buckling of a given size, there exists a minimum critical concentration which is determined by the film thickness and the ratio of the Dupré constant to Young's modulus of the film.
The 3D mesoporous, well crystalline RuO2 film prepared via the evaporation-induced self-assembled method (EISA) successfully demonstrates the extremely high power performances (e.g., excellent capacitive behavior at 10,000mVs−1, ultrahigh-frequency capacitive responses (the absence of a knee point in the Nyquist plot), and 2.6MWkg−1 with an acceptable energy density of 4.6Whkg−1). These excellent capacitive performances were identified by means of voltammetric and electrochemical impedance spectroscopic (EIS) analyses. The mesoporous (with mean pore spacing of 18.1nm) and crystalline nature of this film was characterized by means of the field emission scanning electron microscopy (FE-SEM), Brunaur–Emmett–Teller (BET) method, small-angle X-ray scattering (SAXRS), high-resolution transmission electron microscopy (HR-TEM), electron diffraction (ED), and X-ray diffraction (XRD) analyses. This mesoporous, well crystalline RuO2 film constrains the redox transition to the superficial region meanwhile the tailored mesoporous structure increases the electrochemically active centers, promotes the penetration of electrolytes, provides the “proton reservoirs”, and enhances the rate of electron transport simultaneously for the ultrahigh power application. The specific capacitance of this mesoporous RuO2 can be enhanced from 84 to 185Fg−1 after the microwave-assisted hydrothermal treatment.
In this work, composite polymer electrolytes which consist of polyethylene oxide (PEO) as the polymer matrix, lithium tetrafluoroborate (LiBF4) as the lithium salt and functionalized SiO2 as the inert ceramic filler are prepared by a film-casting method. SiO2 is functionalized by 2-[methoxy(polyethylenoxy)-propyl] trimethoxy silane. X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) are used to characterize the functionalized SiO2. Compared with untreated SiO2 as the ceramic filler there is noticeable improvement in ionic conductivity, stability of the Li/polymer electrolyte interface, and the mechanical properties when functionalized SiO2 is used.