Polarity Cycle Research Articles

Janus Polymer Composite Electrolytes Improve the Cycling Performance of Lithium-Oxygen Battery.

The liquid electrolytes in lithium-air (oxygen) batteries are prone to volatilize, leak, flame, and cause uneven deposition of lithium during cycling, which makes the batteries to face serious problems in terms of safety and cycling stability. A novel Janus quasi-solid composite polymer electrolyte was fabricated by perfluorosulfonic acid (Nafion) membranes with tunable thickness and poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP). The Nafion membranes not only guarantee the mechanical strength of the composites but also effectively prevent the migration of certain anions and macromolecules. The results indicate that Janus quasi-solid composite polymer electrolytes have excellent thermal stability, high lithium-ion migration number, and wide electrochemical window. Lithium-oxygen batteries using the novel quasi-solid composite electrolytes perform lower polarization and better cycling stability. The excellent properties of the quasi-solid composite electrolytes make it one of the effective materials for improving the cycling stability of lithium-air (oxygen) batteries.

Solar dynamo modes of oscillations and the long- term prediction of solar activity

We verify that the values and dates of occurrence of sunspot maxima during Schwabe sunspot cycles ##19 to 24 as predicted by Derek Justin Schove in 1955 coincide with the actually observed ones with a high degree of accuracy. A question arises from this result: why is such a deterministic behavior apparent in a system, like the solar dynamo, that is in principle stochastic. We find that solar activity related data may be well represented by the addition of a constant level and eight modes of oscillation. The repetitive behavior and the relationships that appears to exist between these modes, opens the possibility for a long-term prediction of solar activity. In that line, we forecast the Gleissberg cycle for the forthcoming two centuries and data on sunspot maxima for the next century. Thus, we predict the values and dates of occurrence of sunspot maxima ##25 to 35 and find that the new Episode of solar activity that started during polar cycle #24, as a follow-up of the 20th century Grand Maximum, is of the Regular type and, as the ongoing Hallstatt oscillation will pass through zero from negative to positive around the year 2036, it will last for the remainder of the present millennium. We also find that modes of oscillations are mutually related through a forced non-linear oscillator with a persistent asymmetry. A brief discussion of the origin of this behavior on the excitation of solar dynamo motions by solar-planetary forces is presented.

Using a Heme‐Based Nanozyme as Bifunctional Redox Mediator for Li−O2 Batteries

AbstractThe realization of practical aprotic Li−O2 batteries is hindered by superoxide‐related parasitic reactions and high overpotentials. Herein, a heme‐based nanozyme containing iron‐porphyrin derivative ligands is used as a novel electrolyte additive to scavenge superoxide radicals in the Li−O2 system. Specially, this type of nanozyme can act as a bifunctional catalyst for both discharge and charge by coordinating with superoxide intermediates, functioning as a molecular shuttle of superoxide species and electrons between cathodes and products. As a consequence, the Li−O2 batteries exhibit boosted discharge capacity, reduced charge polarization and superior cycling stability in the presence of the nanozyme additive. This first attempt to using nanozyme in Li−O2 batteries should pave a new way for the sustainable cross‐link between biomimetic enzymes and advanced energy storage.

Preparation and application of poly(ethylene oxide)‐based all solid‐state electrolyte with a walnut‐like SiO2 as nano‐fillers

ABSTRACTPoly(ethylene oxide) (PEO) is one of the most promising candidates in polymer solid‐state electrolyte. However, the polymer matrix has a high degree of crystallinity and thus manifests low conductivity, which restricts its application in all solid‐state lithium‐ion battery. Herein, a new composite polymer electrolyte (PLWLS), which is comprised of PEO, LiClO4, and the independently synthetized walnut‐like SiO2 (WLS) as nano‐fillers, is designed and prepared by the tape‐casting way. The optimum mass fraction of walnut‐like SiO2 is determined by physical and electrochemical characterization. The result shows that the PLWLS‐15 with 15 wt % walnut‐like SiO2 nanoparticles has a crystallinity of 13.7%. Similarly, the maximum tensile strength is improved greatly. The assembled all‐solid‐state lithium‐ion battery with LiFePO4/PLWLS‐15/Li exhibits a higher discharge capacity of 167 mAh g−1 at 0.1 C (1C = 170 mAh g−1) and 143 mAh g−1 at 0.5 C in first cycle, lower voltage polarization and better cycle performance. Therefore, adding nanoparticle into PEO‐based solid‐state electrolyte could effectively promote the mechanical property and electrochemical performance, and thus provide a possibility of application for PLWLS‐15 in next generation all solid‐state lithium battery. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48810.

Development of anodic and cathodic blisters at a model Zn/epoxy interface studied using local electrochemical impedance

Local electrochemical impedance spectroscopy (LEIS) and mapping (LEIM) were used in situ to follow blistering on a model epoxy-coated hot-dip galvanized steel without any initial artificial defects during alternating open circuit potential (OCP)/cathodic polarization cycles. Zones with high admittance were evident from the early stages of degradation, when no blisters were visible. Some of the zones (type I) could be distinguished on the admittance maps obtained at both open circuit and applied cathodic potentials. Other zones (type II) were not detectable by LEIM at OCP but were visible on the maps obtained under cathodic polarization. Blisters developed on both types of zones. Comparing the LEIS responses of the blistered zones with the responses of a model Zn/Cu galvanic couple, the observed behavior was attributed to the formation of a galvanic couple between the blisters, and consequently a gradual increase of anodic and cathodic activities in blisters of types I and II. LEIM is a flexible tool able to differentiate in situ between the development of anodic and cathodic zones on immersed polymer-coated metallic substrates on application of different DC biases or AC frequencies.

Outcome of Relapsed DLBCL Patients, Treated with Polatuzumab-BR or Polatuzumab-R: Real Life Data

Introduction The therapeutic options for diffuse large cell B cell lymphoma (DLBCL) patients (pts) that fail to respond/relapse after≥2 treatment regimens are limited. The SCHOLAR-1 study reported an overall response/ complete remission (ORR/CR) rates of 26%/ 7% with a median overall survival (OS) of 6.3 months in chemorefractory and early relapsing DLBCL pts. Polatuzumab vedotin (Pola) is a conjugated antibody that delivers the microtubule inhibitor MMAE to CD79b-expressing cells. Polatuzumab administered in combination with Bendamustine-Rituximab (P-BR) has been recently approved by the FDA for pts with relapsed/refractory (R/R) DLBCL that failed to respond≥2 prior therapies. The current study investigated the tolerability and efficacy of Pola mainly with BR, in DLBCL pts, treated through a compassionate program after failing ≥2 prior regimens. Methods Data of all pts with consecutive R/R DLBCL, treated with Pola-BR or Pola-R (2-8 cycles) in 11 Israeli centers between 6/2018 and -5/2019 were analyzed. Inclusion criteria for this study were: R/R DLBCL (denovo and transformed follicular lymphoma [t-FL]), age ≥ 18 years, ≥ 2 prior treatments. We evaluated pt characteristics, treatment details and toxicities, overall response and CR rates, progression free survival (PFS) and OS. Cox regression model was used to define factors affecting outcomes. Results 34 patients- (denovo DLBCL, n=24 and t-FL, n=10 ⌈50% -non CGB and 50% - GCB type⌉) were included. Median age at Pola administration was 65.5 (range 60-72) years. Stage ≥3 disease was recorded in 88% and IPI ≥3 in 73.5%. Median prior lines was 3 (range 3-5); including anthracyclines and rituximab in 100% and cisplatin-based regimens in 91%. 32% relapsed after ASCT and 9% after CART infusion. 53% had primary refractory disease, 29% had refractory relapse and 18% had prior sensitive relapse. 22 pts received Pola-B, mostly with Rituximab (n=19), and 12 received Pola-R. In 5 pts, Pola-based regimen was used as a bridge for Allo SCT (all responded CR, n=4 and PR, n=1) and in 6 as a bridge to CARTs (all responded CR n=1, PR n=2, SD n=3). Median number of Pola B cycles was 3 (3-5) and median Pola-R cycles was 4 (3-6). Median B dose per cycle was 90 mg/m2 (45-90). GCSF was used in 47%. Early treatment discontinuation due to progressive disease (PD) occurred in 8 (23%) of the entire cohort: 23% of Pola-B pts and 25% of Pola-R pts. Safety: Hematological AEs grade 3-4, reported with Pola- B vs Pola-R were: neutropenia (45.5.% vs 33%), thrombocytopenia (25% vs 8%) and anemia (23% vs 17%). Infections were recorded in 41% and 36% of Pola-B pts and Pola-R respectively. Neutropenic fever was reported in 36% in Pola-B pts and none in Pola-R. Pulmonary infections were recorded in 33.3% and 27.3% of Pola-B and Pola-R pts respectively, resulting in death in one pt. Peripheral neuropathy occurred in 18% of Pola- B pts (grade ≤2) vs 8% with Pola -R. Hospitalization due to AEs was recorded in 41% of Pola-B vs 25% of Pola-R. Pola dose reduction due to AE was reported in 1 pt (8%) in the Pola-R. Efficacy: ORR for the entire cohort was 65%, including 38% CRs and 27% PRs. 12% pts attained SD and 23% experienced PD. ORR was higher in non-GCB than in GCB pts 80% vs 43% (p=0.036). Median follow up of the entire cohort from Pola administration was 4.4 months (range 0.6-11.4). 6 months projected OS and PFS were 83% and 63%, respectively. Post Pola treatment in pts that failed to respond/Relapsed post pola: 8 patients had PD; 3 died from progression, 1-CART, 1-Allo SCT, 2-paliative care and 1-unknown. Additional 5 pts progressed during follow up; 4-CART and 1-palliative care. 1 patient continues Pola treatment after achieving SD. Univariate analysis for factors predicting PFS and OS GCB type (HR-1.816, P=0.055), Primary refractory vs relapsed disease (HR-1.507, p=0.049) and a higher number of prior lines since diagnosis (HR-1.35, p=0.079) tended to be associated with shorter time to progression. T-FL vs denovo DLBCL was associated with decreased OS (p=0.008). Data of 60 patients, including pts treated recently, therefore, not evaluable at the time of abstract submission, would be presented at ASH. Conclusions The toxicity of Pola-based regimen was relatively low. Pola based treatment provided an encouraging PFS and OS in pts with R/R DLBCL that failed to respond ≥2 prior therapies, treated in a real-life setting. Primary refractory disease, higher number prior lines and t-FL vs denovo DLBCL were associated with inferior outcome. Figure Disclosures Herishanu: Roche: Honoraria; AbbVie: Honoraria; Janssen: Honoraria.

CO2 Nanoenrichment and Nanoconfinement in Cage of Imine Covalent Organic Frameworks for High-Performance CO2 Cathodes in Li-CO2 Batteries.

The Li-CO2 battery is an emerging green energy technology coupling CO2 capture and conversion. The main drawback of present Li-CO2 batteries is serious polarization and poor cycling caused by random deposition of lithium ions and big insulated Li2 CO3 formation on the cathode during discharge. Herein, covalent organic frameworks (COF) are identified as the porous catalyst in the cathode of Li-CO2 batteries for the first time. Graphene@COF is fabricated, graphene with thin and uniform imine COF loading, to enrich and confine CO2 in the nanospaces of micropores. The discharge voltage is raised by higher local CO2 concentration, which is predicted by the Nernst equation and realized by CO2 nanoenrichment. Moreover, uniform lithium ion deposition directed by the graphene@COF nanoconfined CO2 can produce smaller Li2 CO3 particles, leading to easier Li2 CO3 decomposition and thus lower charge voltage. The graphene@COF cathode with 47.5% carbon content achieves a discharge capacity of 27833 mAh g-1 at 75 mA g-1 , while retaining a low charge potential of 3.5 V at 0.5 A g-1 for 56 cycles.

Cathode porosity is a missing key parameter to optimize lithium-sulfur battery energy density

While high sulfur loading has been pursued as a key parameter to build realistic high-energy lithium-sulfur batteries, less attention has been paid to the cathode porosity, which is much higher in sulfur/carbon composite cathodes than in traditional lithium-ion battery electrodes. For high-energy lithium-sulfur batteries, a dense electrode with low porosity is desired to minimize electrolyte intake, parasitic weight, and cost. Here we report the profound impact on the discharge polarization, reversible capacity, and cell cycling life of lithium-sulfur batteries by decreasing cathode porosities from 70 to 40%. According to the developed mechanism-based analytical model, we demonstrate that sulfur utilization is limited by the solubility of lithium-polysulfides and further conversion from lithium-polysulfides to Li2S is limited by the electronically accessible surface area of the carbon matrix. Finally, we predict an optimized cathode porosity to maximize the cell level volumetric energy density without sacrificing the sulfur utilization.

Stabilization of Li-Se Batteries by Wearing PAN Protective Clothing.

Lithium-selenium (Li-Se) batteries have recently attracted more and more attentions as new secondary battery systems due to the similarity but better performances than lithium-sulfur (Li-S) batteries. However, the dissolution of selenium in electrolytes results in low selenium utilization, concentration polarization, inferior capacities, and unstable cycling performances. Herein, 46.58 wt% of selenium is loaded on carbon cloths through the calcination process, which were directly used as self-supporting cathodes. Carbonized polyacrylonitrile (PAN) nanofiber membranes produced by electrospinning are worn as the protective clothing between the cathode and separator to avoid the loss and dissolution of selenium. The stabilization of Li-Se batteries was enhanced by introducing two interlayers, as expected, they exhibit a stable reversible average capacity of 590 mA h g-1 during 1000 cycles at a current density of 0.5 C (1 C = 675 mA g-1). No polyselenide formation is found during charging/discharging, and the effects of the introduced PAN interlayers on improving the stability and reducing the polarization of the assembled Li-Se batteries are confirmed by mechanistic characterizations. These regulated Li-Se batteries present great application potential in the future, and the design idea can also be promoted to explore other energy storage systems.

Features of the Galactic Cosmic Ray Anisotropy in Solar Cycle 24 and Solar Minima 23/24 and 24/25

We study the role of the drift effect in the temporal changes of the anisotropy of galactic cosmic rays (GCRs) and the influence of the sector structure of the heliospheric magnetic field on it. We analyze the GCR anisotropy in Solar Cycle 24 and solar minimum 23/24 with negative polarity (qA<0) for the period of 2007 – 2009 and near minimum 24/25 with positive polarity (qA>0) in 2017 – 2018 using data of the global network of Neutron Monitors. We use the harmonic analysis method to calculate the radial and tangential components of the anisotropy of GCRs for different sectors (‘+’ corresponds to the positive and ‘−’ to the negative directions) of the heliospheric magnetic field. We compare the analysis of GCR anisotropy using different evaluations of the mean GCRs rigidity related to Neutron Monitor observations. Then the radial and tangential components are used for characterizing the GCR modulation in the heliosphere. We show that in the solar minimum 23/24 in 2007 – 2009 when qA<0, the drift effect is not visibly evident in the changes of the radial component, i.e. the drift effect is found to produce approx 4% change in the radial component of the GCR anisotropy for 2007 – 2009. Hence the diffusion dominated model of GCR transport is more acceptable in 2007 – 2009. In turn, near the solar minimum 24/25 in 2017 – 2018 when qA>0, the drift effect is evidently visible and produces ≈40% change in the radial component of the GCR anisotropy for 2017 – 2018. So in the period of 2017 – 2018 a diffusion model with noticeably manifested drift is acceptable. The results of this work are in good agreement with the drift theory of GCR modulation, according to which, during negative (positive) polarity cycles, a drift stream of GCRs is directed toward (away from) the Sun, thus giving rise to a 22-year cycle variation of the radial GCR anisotropy.

Dielectric properties of a monolayer nano-graphyne structure: Monte Carlo simulations

Abstract In this paper, the dielectric properties of a monolayer nano-graphyne structure, with mixed spins σ = 7/2 and S = 1, have been studied, using Monte Carlo simulations. Firstly, the ground state phase diagrams for a zero temperature value are reported and discussed. Secondly, the dielectric properties of the studied system for a non-zero temperature are examined. The effects of the temperature, the external longitudinal electric and crystal fields on polarization, dielectric susceptibility and hysteresis cycles have been investigated.

Determining Patient Candidacy for Antidepressant Use in Bipolar Disorder

The psychiatric literature is filled with strong sentiments condemning antidepressant use as inappropriate or otherwise harmful to treatment outcomes in bipolar disorder. However, the literature from prospective controlled trials actually shows that monoaminergic antidepressants are neither all-good nor all-bad, but rather, like most medications, can be beneficial, detrimental, or ineffective according to individual patient subtypes and profiles. Large randomized trials point to lack of efficacy, more than risk for polarity switch or cycle acceleration, as the overriding concern when using antidepressants for bipolar disorder. Underappreciated is that the extant literature is based on only a small handful of antidepressants, with a striking lack of randomized trials using any antidepressants developed after 1999, limiting the extent to which class generalizations can be drawn fairly. Clinicians are encouraged to think of individualized bipolar patient candidacy for antidepressant use in light of identifiable patient-specific moderators of treatment outcome. [ Psychiatr Ann. 2019;49(9):386–391.]

The Comparison of Lunar Tidal Characteristics in the Low‐Latitudinal Ionosphere Between East Asian and American Sectors During Stratospheric Sudden Warming Events: 2009–2018

AbstractLongitudinal differences of low‐latitudinal ionospheric responses during five major, four minor, and a none‐stratospheric sudden warming (SSW) winters from 2009 to 2018 between East Asian and American sectors are studied with total electron content (TEC). The time‐shifted semidiurnal (TS) pattern and the amplitude (AM2), phase angle (PAM2), and relative strength (RSM2) of the lunar semidiurnal tide (M2) harmonic in TEC are compared between the two sectors. Main results are as follows: (1) TS patterns, AM2,and RSM2 tend to be more discernable or larger in the American sector than in the East Asian sector. (2) TS patterns and PAM2 correspond well with the moon phase, and the occurrence of TS patterns coincides well with the enhancement of AM2 and RSM2. (3) Such patterns sometimes occur before the polar peak warming and experience several cycles during one event, but the most significant one tends to follow the peak warming. These characteristics are most distinct during major events with low solar activities. Our results support the mechanism that TS patterns in low‐latitudinal ionosphere parameters are due to enhanced lunitidal effects on the E region dynamo. Besides, changes in temperature and wind during SSWs can also contribute to the generation of TS signatures. Longitudinal differences in TEC suggest that the M2 influence on the low‐latitudinal ionosphere tends to be more prominent in the American sector than in the East Asian sector during SSWs. These differences probably result from a combined effect of the longitudinal variety in atmospheric (especially tidal) and electrodynamic processes.

High tunability in lead-free Ba0.85Sr0.15TiO3thick films for microwave tunable applications

Lead free ferroelectric Ba0.85Sr0.15TiO3(BST) thick films were successfully deposited by screen printing process on Ag–Pd/Al2O3 substrates. The microstructure of the samples was analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The thick films showed a good adhesion to the Ag–Pd/Al2O3 substrate, a porous microstructure and uniform thicknessesof about 10 μm. The dielectric properties of BST thick films were studied over a wide frequency range (10-1 Hz to 106 Hz) and in a large temperature range from 25 °C to 350 °C. The AC conductivity in BST thick films was systematically investigated. Ferroelectric characterizations and tunability were also studied at room temperature by polarization cycles P(E) and capacitance C(E) measurements. The high values of dielectric permittivity and tunability (67%) combined with low dielectric loss (tgδ) make Ba0.85Sr0.15TiO3 thick films one of the encouraging candidates for microwave tunable applications.

Non-conventional mechanism of ferroelectric fatigue via cation migration

The unique properties of ferroelectric materials enable a plethora of applications, which are hindered by the phenomenon known as ferroelectric fatigue that leads to the degradation of ferroelectric properties with polarization cycling. Multiple microscopic models explaining fatigue have been suggested; however, the chemical origins remain poorly understood. Here, we utilize multimodal chemical imaging that combines atomic force microscopy with time-of-flight secondary mass spectrometry to explore the chemical phenomena associated with fatigue in PbZr0.2Ti0.8O3 (PZT) thin films. Investigations reveal that the degradation of ferroelectric properties is correlated with a local chemical change and migration of electrode ions into the PZT structure. Density functional theory simulations support the experimental results and demonstrate stable doping of the thin surface PZT layer with copper ions, leading to a decrease in the spontaneous polarization. Overall, the performed research allows for the observation and understanding of the chemical phenomena associated with polarization cycling and their effects on ferroelectric functionality.

PTM AND CELL CYCLE GATING MECHANISMS DEVIATED FOR PROGRESSION OF CANCER

Post translational modifications like phosphorylation, Glycosylation and ADP ribosylation serves as biomarkers and are mainly involved in regulation of signalling pathways, cell polarity and cell cycle progression. So, this review helps in finding the biomarkers in understanding of cancer genome and also the deviations observed in gating mechanisms. Mucin 3 is mainly involved in EMT transition and Phosphorylation is also required for effective complex formation between catenin and cadherin. Hyaluron acts as medium for the tumors cells and aids in their movement and responsible for metastatic development. Epigenetic modification like methylation is helpful for cancerous genome to develop additional mutations for survival of the genome.&#x0D; Key words: Cyclin D, PTMs, Gating, Glycosylation, Phosphorylation.

Asymmetric recruitment and actin-dependent cortical flows drive the neuroblast polarity cycle.

During the asymmetric divisions of Drosophila neuroblasts, the Par polarity complex cycles between the cytoplasm and an apical cortical domain that restricts differentiation factors to the basal cortex. We used rapid imaging of the full cell volume to uncover the dynamic steps that underlie transitions between neuroblast polarity states. Initially, the Par proteins aPKC and Bazooka form discrete foci at the apical cortex. Foci grow into patches that together comprise a discontinuous, unorganized structure. Coordinated cortical flows that begin near metaphase and are dependent on the actin cytoskeleton rapidly transform the patches into a highly organized apical cap. At anaphase onset, the cap disassembles as the cortical flow reverses direction toward the emerging cleavage furrow. Following division, cortical patches dissipate into the cytoplasm allowing the neuroblast polarity cycle to begin again. Our work demonstrates how neuroblasts use asymmetric recruitment and cortical flows to dynamically polarize during asymmetric division cycles.

Creative Careers: The Life Cycles of Nobel Laureates in Economics

We identify two polar life cycles of scholarly creativity among Nobel laureate economists with Tinbergen falling broadly in the middle. Experimental innovators work inductively, accumulating knowledge from experience. Conceptual innovators work deductively, applying abstract principles. Innovators whose work is more conceptual do their most important work earlier in their careers than those whose work is more experimental. Our estimates imply that the probability that the most conceptual laureate publishes his single best work peaks at age 25 compared to the mid-50 s for the most experimental laureate. Thus, while experience benefits experimental innovators, newness to a field benefits conceptual innovators.

Intercalated Electrolyte with High Transference Number for Dendrite‐Free Solid‐State Lithium Batteries

AbstractSolid‐state lithium (Li) batteries using solid electrolytes and Li anodes are highly desirable because of their high energy densities and intrinsic safety. However, low ambient‐temperature conductivity and poor interface compatibility of solid electrolytes as well as Li dendrite formation cause large polarization and poor cycling stability. Herein, a high transference number intercalated composite solid electrolyte (CSE) is prepared by the combination of a solution‐casting and hot‐pressing method using layered lithium montmorillonite, poly(ethylene carbonate), lithium bis(fluorosulfonyl)imide, high‐voltage fluoroethylene carbonate additive, and poly(tetrafluoroethylene) binder. The electrolyte presents high ionic conductivity (3.5 × 10−4 S cm−1), a wide electrochemical window (4.6 V vs Li+/Li), and high ionic transference number (0.83) at 25 °C. In addition, a 3D Li anode is also fabricated via a facile thermal infusion strategy. The synergistic effect of high transference number intercalated electrolyte and 3D Li anode is more favorable to suppress Li dendrites in a working battery. The solid‐state batteries based on LiFePO4 (Al2O3 @ LiNi0.5Co0.2Mn0.3O2), CSE, and 3D Li deliver admirable cycling stability with discharge capacity 145.9 mAh g−1 (150.7 mAh g−1) and capacity retention 91.9% after 200 cycles at 0.5 C (92.0% after 100 cycles at 0.2 C) at 25 °C. This work affords a splendid strategy for high‐performance solid‐state battery.

Moving toward Noninvasive, Focused Ultrasound Therapeutic Delivery of Drugs in the Brain: Prolonged Opening of Blood-Brain Barrier May Not Be Needed.

Moving toward Noninvasive, Focused Ultrasound Therapeutic Delivery of Drugs in the Brain: Prolonged Opening of Blood-Brain Barrier May Not Be Needed.