Ternary composites of poly(vinylidene fluoride-co-hexafluoropropylene) with silver nanowires and titanium dioxide nanoparticles as separator membranes for lithium-ion batteries

In the realm of polymer composites, there is growing interest in the use of more than one filler for achieving multifunctional properties. In this work, a composite separator membrane has been developed for lithium-ion battery application, by incorporating conductive silver nanowires (AgNWs) and titanium dioxide (TiO2) nanoparticles into a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer matrix. The composite membranes were manufactured by solvent casting and thermally induced phase separation, with total filler content varying up to 10 wt%. The ternary composites composites present improved mechanical characteristics, ionic conductivity and lithium transfer number compared to the neat polymer matrix. On the other hand, the filler type and content within the composite has little bearing on the morphology, polymer phase, or thermal stability. Once applied as a separator in lithium-ion batteries, the highest discharge capacity value was obtained for the 5 wt% AgNWs/5 wt% TiO2/PVDF-HFP membrane at different C-rates, benefiting from the synergetic effect from both fillers. This work demonstrates that higher battery performance can be achieved for next-generation lithium-ion batteries by using separator membranes based on ternary composites.

Experimental and theoretical insights into the supercapacitive performance of interconnected WS2 nanosheets

Transition metal dichalcogenides (TMDs) are fascinating and prodigious considerations in the electrochemical energy storage sector because of their two dimensional chemistry as well as heterogeneous characteristics. Herein, we synthesized interconnected WS2 nanosheets by a hydrothermal method followed by sulphuration at 850 °C in an argon atmosphere. The ultrathin WS2 nanosheet array is endowed with an excellent specific capacitance of 74 F g-1 at the current density of 3 A g-1 up 7000 cycles. Moreover, a symmetric supercapacitor was fabricated using WS2 nanosheets, which provided the admirable high specific capacity of 6.3 F g-1 at 0.05 A g-1 with the energy and power density of 5.6 × 102 mW h kg-1 and 3.6 × 10 5 mW kg-1, respectively. Density functional theory (DFT) simulations revealed the presence of populated energy states near the Fermi level resulting in a high quantum capacitance value, which supports the experimentally achieved high capacitance value. The attained results recommend interconnected WS2 nanosheets as a novel, robust, and low-cost electrode material for supercapacitor energy storage devices.

Exchanging Anion in CuCo-Carbonate Double Hydroxide for Faradaic Supercapacitors: A Case Study

A systematic synthetic method involving the anion exchange process was designed and developed to fabricate the superior functioning three-dimensional (3-D) urchin-architectured copper cobalt oxide (CuCo₂O₄; CCO) and copper cobalt sulfide (CuCo₂S₄; CCS) electrode materials from copper-cobalt carbonate double hydroxide [(CuCo)₂(CO₃)(OH)₂; CCH]. The effective tuning of chemical, crystalline, and morphological properties was achieved during the derivatization process of CCH, based on the anion exchange effect and phase transformation without altering the 3-D spatial assembly. Benefiting from morphological and structural advantages, CCO and CCS exhibited superior electrochemical activity with capacity values of 1508 and 2502 C g^-1 at 10 A g^-1 to CCH (1182 C g^-1 at 10 A g^-1). The thermal treatment of CCH has generated a highly porous nature in nanospikes of 3-D urchin CCO structures, which purveys betterment in electrochemical phenomena than pristine smooth-surfaced CCH. Meanwhile, the sulfurization reaction induced the anion effect to a greater extent in the CCS morphology, resulting in hierarchical 3-D urchins formed by 1-D nanospikes constituting coaxially swirled 2-D nanosheets with high exposure of active sites, specific surface areas, and 3-D electron/ion transportation channels. The asymmetric supercapacitor was constructed with a superior CCS electrode as a cathode and an activated carbon electrode as an anode, showing a high specific capacity of 287.35 C g^-1 at 7 A g^-1 and durability for 5000 cycles with 94.2% retention at a high current density of 30 A g^-1. The ultrahigh energy and power density of 135.3 W h kg^-1 (10 A g^-1) and 44.35 kW kg^-1 (30 A g^-1) were harvested during the PC device performance. Our finding proposes an idea about the importance of anions and phase transformation as a versatile tool for engineering high-functioning electrode materials and their endeavor toward overwhelming the major demerit of SCs by aggrandizing the energy density value and rate performance.

Laser intensity profile based terahertz field enhancement from a mixture of nano-particles embedded in a gas

Nano-particle embedded system plays an importance in developing of future terahertz (THz) radiation source for real-world applications. The laser interactions with nanoparticle embedded system can produce a wide range of THz radiation due to plasma oscillations excitation. We investigate THz field generation from the laser-beat wave interaction with a mixture of spherical and cylindrical graphite nanoparticles in argon gas. Different laser intensity distributions such as Gaussian, cosh-Gaussian, flat-top and ring shape laser pulses have been studied in this work. The relevant plasmon resonance conditions with appropriate symmetry of spherical nanoparticles and cylindrical nanoparticles are discussed. THz field is enhanced upto the order of 10 2 when the laser intensity redistributes along the polarization direction for a ring shape field envelope.

Carbon spheres decorated-graphene oxide framework as an excellent active material for redox flow battery and supercapacitors

Composite of dextrose-derived oxygen-rich carbon spheres and graphene oxide, synthesised using a cost-effective and easy hydrothermal process, was used as an active material in two of the trending and promising energy storage devices. The surface morphology and properties of the composite were studied using scanning electron microscope, X-ray diffractometer, energy dispersive X-ray analysis, elemental mapping and Raman spectra. To analyse the electrochemical behaviour of the material, several electrochemical techniques such as cyclic voltammetry (CV), chronopotentiometry, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation study were used. The reversibility of Fe²⁺/Fe³⁺ redox species and resistance offered by electrolyte towards the modified electrode were studied using CV, EIS and Tafel studies. Further evaluation of efficacy of the active material towards the iron redox flow battery (IRFB) of 132 cm² area was analysed by performing charge discharge studies at varied current densities. Substantial increase in the electrochemical performance of the IRFB with a coulombic efficiency (CE) 93% along with the good life cycle stability up to 25 cycles was observed. The composite was also used as a superior electrode material for supercapacitor application resulting in significant enhancement in the electrochemical performance with specific capacitance of 610 F g^-1 and CE of 83% with 93% retention up to 1600 cycles.

Bimetallic persulfide nanoflakes assembled by dealloying and sulfurization: a versatile electro-catalyst for overall water splitting and Zn–air batteries

(CoFe)(S2)2 nanoflakes with graphene-like edges have been synthesized through dealloying and sulfurization, and exhibit multi-functional electro-catalytic performance toward the ORR, OER, HER.

THREE-POINT AREA METHOD FOR THERMOLUMINESCENCE GLOW CURVE ANALYSIS AND ITS APPLICATION TO THE GLOW PEAK OF K2SRP2O7:PR

A method has been proposed to evaluate the kinetic parameters, viz. activation energy ($E$) and order of kinetics ($b$) from a single or isolated thermoluminescence (TL) glow peak. Along with the area under the entire curve, this method uses a set of three arbitrary data points and calculates the partial area under the curve from each point to the endpoint. In this way, the entire information associated with the curve is used and the method is named as 'Three-Point Area' (TPA) method. We have applied it successfully on a number of theoretically simulated TL curves generated in One Trap One Recombination centre (OTOR) model and General-Order Kinetics (GOK) model under quasi-equilibrium approximations with linear heating scheme. The activation energies are found in good agreement with input values for both the models. For OTOR model, temperature average of order of kinetics is estimated to compare with the present result. Systematic analysis is carried out for estimation of errors inherent in the method in the purview of GOK model. A closer look on the results reveals that any set of three points, preferably chosen from the rising side of the curve, can yield activation energy and order of kinetics. The validity of the method to extract $E$ and $b$ from experimental glow curves is exemplified by considering experimental TL data reported in literature. Finally, a complete study starting from the synthesis of a new phosphor $\mathrm{K_2SrP_2O_7:Pr} $ and analysis of the recorded TL data to estimate $E$ and $b$ employing the TPA method has been reported.

Self-Supported 3 D Ultrathin Cobalt-Nickel-Boron Nanoflakes as an Efficient Electrocatalyst for the Oxygen Evolution Reaction

The development of highly active and efficient nonprecious-metal electrocatalysts for the oxygen evolution reaction is important for the design of renewable energy production and storage devices. In this work, highly dense, ultrathin Co-Ni boride nanoflakes supported on a 3 D CoNi skeleton are fabricated in situ by a simple one-step, high-temperature, solid-state boronation process. As a result of the induced high electroactive surface area and low charge transfer resistance, CoNiB-700 exhibits high catalytic activity at an overpotential of 262 (η₁₀ ) and 284 mV (η₂₀ ) to deliver current densities of 10 and 20 mA cm^-2 , respectively, with a Tafel slope of 58 mV dec^-1 in an alkaline medium towards the oxygen evolution reaction. DFT calculations show that the Ni-regulated Co-B compound has a lower rate-determining energy barrier for the *OOH intermediate than the mono-Co-B compound, which facilitates the production of more active catalytic sites for an accelerated surface charge-transfer process for the oxygen evolution reaction.

Design of P-Doped Mesoporous Carbon Nitrides as High-Performance Anode Materials for Li-Ion Battery

Herein, we demonstrate a simple and unique strategy for the preparation of P-doped into the substructure of mesoporous carbon nitride materials (P-MCN-1) with ordered porous structures as a high-energy and high-power Li-ion battery (LIB) anode. The P-MCN-1 as an anode in LIB delivers a high reversible discharge capacity of 963 mAh g^-1 even after 1000 cycles at a current density of 1 A g^-1, which is much higher than that of other counterparts comprising s-triazine (C₃H₃N₃, g-C₃N₄), pristine MCN-1, and B-containing MCN-1 (B-MCN-1) subunits or carbon allotropes like CNT and graphene (rGO) materials. The P-MCN-1 electrode also exhibits exceptional rate capability even at high current densities of 5, 10, and 20 A g^-1 delivering 685, 539, and 274 mAh g^-1, respectively, after 2500 cycles. The high electrical conductivity and Li-ion diffusivity (D), estimated from electrochemical impedance spectra (EIS), very well support the extraordinary electrochemical performance of the P-MCN-1. Higher formation energy, lower bandgap value, and high Li-ion adsorption ability predicted by first principle calculations of P-MCN-1 are in good agreement with experimentally observed high lithium storage, stable cycle life, high power capability, and minimal irreversible capacity (IRC) loss. To the best of our knowledge, it is an entirely new material with the combination of ordered mesostructures with P codoping in carbon nitride substructure which offers superior performance for LIB, and hence we believe that this work will create new momentum for the design and development of clean energy storage devices.

Hybrid Ni3S2–MoS2 nanowire arrays as a pH-universal catalyst for accelerating the hydrogen evolution reaction

Hybrid Ni₃S₂–MoS₂ NWAs/NF obtained via a facile two-step hydrothermal route shows high catalytic performance toward hydrogen evolution in a pH-universal environment.

Co(OH)2@MnO2 nanosheet arrays as hybrid binder-free electrodes for high-performance lithium-ion batteries and supercapacitors

Co(OH)₂@MnO₂ nanosheet arrays were directly grown on nickel foam via two-step electrodeposition method with subsequent heat treatment at 170 °C.

The morphology-dependent electrocatalytic activities of spinel-cobalt oxide nanomaterials for direct hydrazine fuel cell application

Morphologically-tuned spinel-cobalt oxide nanomaterials such as pellet-, flower-, cube- and sheet-like structures as an anode for an enhanced hydrazine oxidation reaction (HOR) is demonstrated.

Arsenic load in rice ecosystem and its mitigation through deficit irrigation

Rice the staple food is a notable intake source of arsenic to the rural population of eastern India through food-chain. A field survey was carried out to study the variation of arsenic load in different parts of rice genotype Shatabdi (most popular genotype of the region) exposed to varying level of arsenic present in the irrigation water and soil. As irrigation is the primary source of arsenic contamination, a study was conducted to assess arsenic load in rice ecosystem under deficit irrigation practices like intermittent ponding (IP), saturation (SAT) and aerobic (AER) imposed during stress allowable stage (16-40 days after transplanting) of the crop (genotype Shatabdi). Present survey showed that arsenic content in water and soil influenced the arsenic load of rice grain. Variation in arsenic among different water and soil samples influenced grain arsenic load to the maximum extent followed by straw. Deviation in root arsenic load due to variation in water and soil arsenic content was lowest. Arsenic concentration of grain is strongly related to the arsenic content of both irrigation water and soil. However, water has 10% higher impact on grain arsenic load over soil. Translocation of arsenic from root to shoot decreased with the increase in arsenic content of water. Imposition of saturated and aerobic environment reduced both yield and grain arsenic load. In contrast under IP a marked decrease in grain arsenic content recorded with insignificant reduction in yield. Deficit irrigation resulted in significant reduction (17.6-25%) in arsenic content of polished rice and the values were lower than that of the toxic level (<0.2 mg kg^-1). In contrast the decrease in yield was to the tune of 0.9% under IP regime over CP.

Intraguild Predation in Heteroptera: Effects of Density and Predator Identity on Dipteran Prey

In tropical freshwaters, different species of water bugs (Heteroptera) constitute a guild sharing similar prey resources including chironomid and mosquito larvae. Assuming possibilities of intraguild predation (IGP) among the constituent members, an attempt was made to evaluate the effects of prey and predator density on the mortality of mosquito and chironomid larvae (shared prey), using Laccotrephes griseus Guérin-Méneville (Hemiptera: Nepidae) and Ranatra filiformis Fabricius (Hemiptera: Nepidae) as IG predators and Anisops bouvieri Kirkaldy (Hemiptera: Notonectidae) as IG prey. The predation on mosquito and chironomid larvae varied with the density and combinations of the predators. When present as conspecific IG predators, L. griseus exhibited greater effect on the prey mortality than R. filiformis. The effects on shared prey suggest that the two predators are not substitutable in terms of the effect on the shared prey mortality. The mortality of A. bouvieri (IG prey) at low shared prey density was significantly different (p < 0.05) from high shared prey density. In view of predatory effect of the heteropteran predators on the dipteran larvae, the results suggest possible interference by the presence of A. bouvieri as an intermediate predator. It seems that the presence of heteropteran predators including A. bouvieri as IG prey may benefit the dipteran prey under situations when the density is low in tropical waters. The intensity of the predatory effect may differ based on the species composition at IG predator level. For mosquito biological control, the interactions between the predators may not be substitutable and are independent in their effects.

Enhanced x-ray emission from nano-particle doped bacteria

Recently, it has been greatly appreciated that intense light matter interaction is modified due to the nano- and microstructures in the target by--surface plasmons, laser energy localization scattering etc. Extreme laser intensities produce dense plasmas and collective mechanisms generate energetic electrons, ions and hard x-rays. Recently, it is postulated that the anharmonic electron motion, driven by ultrashort, high-intensity laser pulses, provides a universal mechanism for the laser absorption. Here, we provide the first demonstration of anharmonic-resonance-aided high laser-absorption in a biological system. At intensities of ∼ 10¹⁶⁻¹⁸ W/cm², 40 fs pulses excite a plasma formed with E. coli bacteria. The density-inhomogeneities due to the micro- and nanostructures in the bacterial target increase anharmonic resonance (AHR) heating and result in a 10⁴-fold enhancement in the hard x-ray yield compared to plain solid targets. These observations lead to novel high-energy x-ray sources that have implications to lithography, imaging and medical applications.

Nuclear ULK1 promotes cell death in response to oxidative stress through PARP1

Reactive oxygen species (ROS) may cause cellular damage and oxidative stress-induced cell death. Autophagy, an evolutionarily conserved intracellular catabolic process, is executed by autophagy (ATG) proteins, including the autophagy initiation kinase Unc-51-like kinase (ULK1)/ATG1. Although autophagy has been implicated to have both cytoprotective and cytotoxic roles in the response to ROS, the role of individual ATG proteins, including ULK1, remains poorly characterized. In this study, we demonstrate that ULK1 sensitizes cells to necrotic cell death induced by hydrogen peroxide (H2O2). Moreover, we demonstrate that ULK1 localizes to the nucleus and regulates the activity of the DNA damage repair protein poly (ADP-ribose) polymerase 1 (PARP1) in a kinase-dependent manner. By enhancing PARP1 activity, ULK1 contributes to ATP depletion and death of H2O2-treated cells. Our study provides the first evidence of an autophagy-independent prodeath role for nuclear ULK1 in response to ROS-induced damage. On the basis of our data, we propose that the subcellular distribution of ULK1 has an important role in deciding whether a cell lives or dies on exposure to adverse environmental or intracellular conditions.

Anomalous collisional absorption of laser pulses in underdense plasma at low temperature

In a previous paper [M. Kundu, Phys. Plasmas 21, 013302 (2014)], fractional collisional absorption (α) of laser light in underdense plasma was studied by using a classical scattering model of electron-ion collision frequency ν(ei), where total velocity v=√[v(th)(2)+v(0)(2)] (with v(th) and v(0) as the thermal and the ponderomotive velocity of an electron) dependent Coulomb logarithm lnΛ(v) was shown to be responsible for the anomalous (unconventional) increase of ν(ei) and α(∝ν(ei)) with the laser intensity I(0) up to a maximum value about an intensity I(c) in the low temperature (T(e)<15eV) regime and a conventional ≈I(0)(-3/2) decrease when I(0)≫I(c). One may object that the anomalous increase in ν(ei) and α were partly due to the artifact introduced in lnΛ through the maximum cutoff distance b(max)∝v. In this work, we show similar anomalous increase in ν(ei) and α versus I(0) (in the low temperature and underdense density regime) with more accurate quantum and classical kinetic models of ν(ei) without using lnΛ, but with a proper choice of the total velocity dependent inverse cutoff length k(max)∝v(2) (classical) or k(max)∝v (quantum). For a given I(0)<5×10(14)Wcm(-2), ν(ei) versus T(e) also exhibits so far unnoticed identical anomalous increase as ν(ei) versus I(0), even if the conventional k(max)∝v(th)(2) or k(max)∝v(th) (without v(0)) is chosen. The total velocity dependent k(max) in the kinetic models, as proposed here, is found to explain the anomalous increase of α with I(0) measured in some earlier laser-plasma experiments.

Poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) lithium-ion battery separator membranes prepared by phase inversion

Separator membranes based on poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) were prepared by a solvent casting technique based on its phase diagram in N,N-dimethylformamide (DMF) solvent.

Bacterial cells enhance laser driven ion acceleration

Intense laser produced plasmas generate hot electrons which in turn leads to ion acceleration. Ability to generate faster ions or hotter electrons using the same laser parameters is one of the main outstanding paradigms in the intense laser-plasma physics. Here, we present a simple, albeit, unconventional target that succeeds in generating 700 keV carbon ions where conventional targets for the same laser parameters generate at most 40 keV. A few layers of micron sized bacteria coating on a polished surface increases the laser energy coupling and generates a hotter plasma which is more effective for the ion acceleration compared to the conventional polished targets. Particle-in-cell simulations show that micro-particle coated target are much more effective in ion acceleration as seen in the experiment. We envisage that the accelerated, high-energy carbon ions can be used as a source for multiple applications.

Hierarchically designed SiOx/SiOy bilayer nanomembranes as stable anodes for lithium ion batteries

Hierarchically designed SiOx /SiOy rolled-up bilayer nanomembranes are used as anodes for lithium-ion batteries. The functionalities of the SiO(x,y) layers can be engineered by simply controlling the oxygen content, resulting in anodes that exhibit a reversible capacity of about 1300 mA h g(-1) with an excellent stability of over 100 cycles, as well as a good rate capability.

Helicobacter Pylori HP0175 Promotes the Production of IL-23, IL-6, IL-1β and TGF-β

Helicobacter pylori infection induces a chronic gastric inflammatory infiltrate. This study was undertaken to evaluate the type of the innate immune responses elicited by the secreted peptidyl-prolyl cis-trans isomerase of H. pylori (HP0175). The cytokine production induced by HP0175 in neutrophils, and monocytes was evaluated. HP0175 was able to induce the expression of IL-23 in neutrophils, and monocytes, and IL-6, IL-1beta and TGF-beta in monocytes. These findings indicate that HP0175 is able to promote the activation of innate cells and the production of a cytokine milieu that may favour the development of Th17 response.

A bright point source of ultrashort hard x-ray pulses using biological cells

We demonstrate that the interaction of intense femtosecond light on a plain solid substrate can be substantially altered by a few micron layer coating of bacterial cells, live or dead. Using E. Coli cells, we show that at an intensity of 10(16)W cm(-2), the bremsstraahlung hard x-ray emission (up to 300 keV), is increased by more than two orders of magnitude as compared to a plain glass slab. Particle-in-cell simulations carried out by modeling the bacterial cells as ellipsoidal particles show that the hot electron generation is indeed enhanced by the presence of microstructures. This new methodology should pave way for using microbiological systems of varied shapes to control intense laser produced plasmas for EUV/x-ray generation.

Estradiol Induced Regression of T47D:A18/PKCα Tumor Involves Translocation of Estrogen Receptor alpha from the Nucleus to the Cytoplasm

Background: Resistance to tamoxifen (TAM) is one of the most challenging problems in the treatment of breast cancer. In our laboratory we have developed a PKCα overexpressing T47D:A18 cell line which is TAMresistant and 17β estradiol (E2) independent compared to the E2 dependent T47D:A18/neo cell line (Chisamore et al, 2001). PKCα overexpression is known to be associated with TAM treatment failure in breast cancer (Tonetti et al, 2003). This T47D:A18/PKCα model exhibits E2-induced tumor regression in in vivo or when grown in matrigel (3D matrix) but not on 2D plastic. Recently we have demonstrated that tumor regression involves participation of estrogen receptor alpha (ERα), Fas/FasL and the extracellular matrix (Zhang et al, 2009). Interestingly membrane impermeable E2-BSA conjugate mediates growth inhibition of T47D:A18/PKCα colonies in matrigel similar to E2 suggesting a potential role of extranuclear ERα. On the basis of our preliminary data we investigated whether extranuclear ERα may play a critical role in E2-induced tumor regression.Materials and methods: T47D:A18/PKCα cells were injected into mammary fat pads of 20 ovariectomized athymic mice. Mice were left untreated and tumors were allowed to grow until the mean tumor size reached 0.5 cm2, then 10 mice were implanted with a 1.0 cm E2 capsule and the other 10 continued with no treatment (control). T47D:A18/neo tumors were also established in 10 athymic mice in the presence of E2. Four micrometer thick sections were prepared from the paraffin embedded T47D:A18/PKCα tumor tissues of control and E2-treated mice and T47D:A18/neo tumors. For immunofluorescence staining, alexa fluor 488 and Cy3 fluorescence tagged secondary antibodies were used against ERα and β-actin primary antibodies respectively.Results: Immunofluorescence images of T47D:A18/PKCα tumor sections from untreated control mice showed that the ERα was mainly localized in the nucleus. Interestingly, treatment with E2 resulted in significant translocation of ERα from the nucleus to the cytoplasm and the plasma membrane of tumor cells. Immunofluorescence analysis of tumor sections obtained from E2 treated mice indicated that approximately 5-10% of cells contained ERα localized to the plasma membrane whereas the majority of ERα was localized to the cytosol. However in T47D:A18/neo tumors the majority of ERα was found in the nucleus suggesting the involvement of the ERE mediated classical pathway in tumor growth.Discussion: This is the first time we are reporting that E2-induced T47D:A18/PKCα tumor regression is accompanied by translocation of ERα to extranuclear sites. E2-induced tumor regression observed in our pre-clinical model suggests E2 or an E2-like compound may be a potential treatment option for patients harboring PKCα overexpressing tumors. Furthermore the extranuclear ERα signaling pathway may be an attractive therapeutic target to treat PKCα overexpressing tumors that are refractory to current endocrine therapies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4140.