Fast Loss Research Articles

On the Similarity and Repeatability of Fast Radiation Belt Loss: Role of the Last Closed Drift Shell

AbstractProperly characterizing fast relativistic electron losses in the terrestrial Van Allen belts remains a significant challenge for accurately simulating their dynamics. In particular, magnetopause shadowing losses can deplete the radiation belt within hours or even minutes, but can have long‐lasting impacts on the subsequent belt dynamics. By statistically analyzing seven years of data from the entire Van Allen Probes mission in the context of the last closed drift shell, here we show how these losses are much more organized and predictable than previously thought. Once magnetic storm electron dynamics are properly analyzed in terms of the location of the last closed drift shell, not only is the loss shown to be repeatable but its energy‐dependent spatio‐temporal evolution is also revealed to follow a very similar pattern from storm to storm. Employing an energy‐dependent ULF wave radial diffusion model, we further show for the first time how the similar and repeatable fractional loss of the pre‐storm electron population in each storm can be reproduced and explained. Empirical characterization of this loss may open a pathway toward improved radiation belt specification and forecast models. This is especially important since underestimates of loss can also create unrealistic sources in models, creating phantom electron radiation and leading to the prediction of an overly harsh radiation environment.

Comparison of uptake and elimination kinetics of metallic oxide nanomaterials on the freshwater microcrustacean Daphnia magna

The widespread use and release of nanomaterials (NMs) in aquatic ecosystems is a concerning issue as well as the fate and behavior of the NMs in relation to the aquatic organisms. In this work, the freshwater microcrustacean Daphnia magna was exposed to 12 different and well-known NMs under the same conditions for 24 h and then placed in clean media for 120 h, in order to determine their different uptake and elimination behaviors. The results showed that most of the tested NMs displayed a fast uptake during the first hours arriving to a plateau by the end of the uptake phase. The elimination behavior was determined by a fast loss of NMs during the first hours in the clean media, mainly stimulated by the presence of food. Remaining NMs concentrations can still be found at the end of the elimination phase. Two NMs had a different profile (i) ZnO-NM110 exhibited increase and loss during the uptake phase, and (ii) SiO2-NM204 did not show any uptake. A toxicokinetic model was applied and the uptake and elimination rates were found along with the dynamic bioconcentration factors. These values allowed to compare the NMs, to cluster them by their similar rates, and to determine that the TiO2-NM102 is the one that has the fastest uptake and elimination behavior, SiO2-NM204 has the slowest uptake and CeO2 <10 nm has the slowest elimination. The present work represents a first attempt to compare different NMs based on their uptake and elimination behaviors from a perspective of the nano-bio interactions influence.

A novel path to runaway electron mitigation via deuterium injection and current-driven MHD instability

Relativistic electron (RE) beams at high current density (low safety factor, q a ) yet very low free-electron density accessed with D2 secondary injection in the DIII-D and JET tokamak are found to exhibit large-scale MHD instabilities that benignly terminate the RE beam. In JET, this technique has enabled termination of MA-level RE currents without measurable first-wall heating. This scenario thus offers an unexpected alternate pathway to achieve RE mitigation without collisional dissipation. Benign termination is explained by two synergistic effects. First, during the MHD-driven RE loss events both experiment and MHD orbit-loss modeling supports a significant increase in the wetted area of the RE loss. Second, as previously identified at JET and DIII-D, the fast kink loss timescale precludes RE beam regeneration and the resulting dangerous conversion of magnetic to RE kinetic energy. During the termination, the RE kinetic energy is lost to the wall, but the current fully transfers to the cold bulk thus enabling benign Ohmic dissipation of the magnetic energy on longer timescales via a conventional current quench. Hydrogenic (D2) secondary injection is found to be the only injected species that enables access to the benign termination. D2 injection: (1) facilitates access to low q a in existing devices (via reduced collisionality & resistivity), (2) minimizes the RE avalanche by ‘purging’ the high-Z atoms from the RE beam, (3) drives recombination of the background plasma, reducing the density and Alfven time, thus accelerating the MHD growth. This phenomenon is found to be accessible when crossing the low q a stability boundary with rising current, falling toroidal field, or contracting minor radius—the latter being the expected scenario for vertically unstable RE beams in ITER. While unexpected, this path scales favorably to fusion-grade tokamaks and offers a novel RE mitigation scenario in principle accessible with the day-one disruption mitigation system of ITER.

Dephasing versus collapse: lessons from the tight-binding model with noise

Condensed matter physics at room temperature usually assumes that electrons in conductors can be described as spatially narrow wave packets—in contrast to what the Schrödinger equation would predict. How a finite-temperature environment can localize wave functions is still being debated. Here, we represent the environment by a fluctuating potential and investigate different unravellings of the Lindblad equation that describes the one-dimensional tight-binding model in the presence of such a potential. While all unravellings show a fast loss of phase coherence, only part of them lead to narrow wave packets, among them the quantum-state diffusion unravelling. Surprisingly, the decrease of the wave packet width for the quantum state diffusion model with increasing noise strength is slower than that of the phase coherence length. In addition to presenting analytical and numerical results, we also provide phenomenological explanations for them. We conclude that as long as no feedback between the wave function and the environment is taken into account, there will be no unique description of an open quantum system in terms of wave functions. We consider this to be an obstacle to understanding the quantum-classical transition.

Numerical study on the loss of fast ions produced by minority ion cyclotron resonance heating in EAST

The classical prompt loss of fast ions produced by minority ion cyclotron resonance heating (ICRH) is studied by a guiding center orbit following code in the Experimental Advanced Superconducting Tokamak (EAST). It is found that the loss of fast ions produced by ICRH mainly appears in both ends of the resonance layer, while the loss of fast ions in the middle resonance layer is very small. The dominant fast loss comes from trapped ions, rather than from passing ions. Controlling the location of resonance layer at the plasma core may be more beneficial to the EAST tokamak ICRH. In addition, the loss distribution of fast ions is studied. The results show that the fast ions are mainly lost near the midplane in the poloidal direction, but almost uniformly in the toroidal direction. Moreover, we investigate the dependence of fast ion loss on the ICRH power. The simulation results show that the loss fraction of fast ions in both ends of the resonance region increases with the ion cyclotron range of frequencies (ICRF) power, but barely affects the loss of fast ions in the middle region.

Neural circuitry underlying REM sleep: A review of the literature and current concepts.

As one of the fundamental sleep states, rapid eye movement (REM) sleep is believed to be associated with dreaming and is characterized by low-voltage, fast electroencephalographic activity and loss of muscle tone. However, the mechanisms of REM sleep generation have remained unclear despite decades of research. Several models of REM sleep have been established, including a reciprocal interaction model, limit-cycle model, flip-flop model, and a model involving γ-aminobutyric acid, glutamate, and aminergic/orexin/melanin-concentrating hormone neurons. In the present review, we discuss these models and summarize two typical disorders related to REM sleep, namely REM sleep behavior disorder and narcolepsy. REM sleep behavior disorder is a sleep muscle-tone-related disorder and can be treated with clonazepam and melatonin. Narcolepsy, with core symptoms of excessive daytime sleepiness and cataplexy, is strongly connected with orexin in early adulthood.

Transient analysis of the main heat-transfer system of the pool-type sodium-cooled fast reactor

<p indent="0mm">Sodium-cooled fast reactors are the first choice of the fourth generation of advanced nuclear energy systems. They have attracted significant attention in the development of advanced nuclear energy technology owing to their advantages of proliferative nuclear fuel, transmutation of radioactive waste, and high thermal efficiency power generation. The design and construction of the secondary sodium-cooled fast reactor are ongoing in China. The physical characteristics of fast neutrons and the special thermal, physical, and chemical properties of liquid sodium metal cause special and complex scientific problems in the design of sodium-cooled fast reactors. In this study, taking the energy transfer process of sodium-cooled fast reactors as the object, we establish mathematical and physical models for analyzing large-scale transients in various energy transfer and conversion processes. The model is verified and validated by the natural circulation test of the Phoenix reactor and the international benchmark of the fast flux test facility loss in flow tests. The trend of the calculated values is consistent with that of the test data, and the results are in good agreement. For a typical pool-type sodium-cooled fast reactor, four types of transient events in the power plant are determined by engineering evaluation and deductive analysis. Among them, there are nine normal operation transients, 23 expected transients, 10 abnormal transients, and 7 emergency transients. Based on the established mathematical and physical models, the analysis results of each type of typical transient are given, which provide an important basis for the design of the system and equipment/components and lay a scientific and technological foundation for completing the design of the transient condition and operation mode of the sodium-cooled fast reactor as well as safety evaluation.

Improvement in Muscle Strength and Metabolic Parameters Despite Muscle Mass Loss in the Initial Six Months After Bariatric Surgery.

An aggravation in pre-existing sarcopenia or the onset of sarcopenia may occur in the scenario of extensive and fast weight loss in the initial months following bariatric surgery. The accurate identification of sarcopenia criteria and its metabolic repercussions is vital for its correct management. The aim of this study is to evaluate the correlation between the diagnosis criteria for sarcopenia and metabolic repercussions during the first 6months following bariatric surgery. A prospective single-center cohort study was conducted. Convenience sampling was performed among patients with severe obesity undergoing preoperative evaluation for bariatric surgery. Metabolic parameters, nutritional evaluation, and skeletal muscle evaluation were assessed before surgery and 6months later. A total of 129 patients were selected, 62 participants were included in the final analysis. Mean age was 37.7years and 88.4% of participants were women. Mean body mass index was 41.8kg/m2 and 47.8% of patients were sedentary. Sleeve gastrectomy was performed in 41 patients and Roux-en-Y gastric bypass in 21 patients. Significant improvement regarding muscle strength and function after surgery was observed. Sarcopenia criteria were not met by any participant before and after surgery. Blood glucose and ferritin levels remained independently associated with change in muscle strength. Functional evaluation methods did not reflect the reduction in skeletal muscle mass demonstrated in bioelectrical impedance analysis 6months after bariatric surgery in comparison to the preoperative baseline. Improvement in muscle strength was followed by improvement in metabolic parameters.

Mechanistic Pathways for N2O Elimination from trans-R3Sn-O-N═N-O-SnR3 and for Reversible Binding of CO2 to R3Sn-O-SnR3 (R = Ph, Cy)

The rate and mechanism of the elimination of N2O from trans-R3Sn-O-N═N-O-SnR3 (R = Ph (1Ph) and R = Cy (1Cy)) to form R3Sn-O-SnR3 (R = Ph (2Ph) and R = Cy (2Cy)) have been studied using both NMR and IR techniques to monitor the reactions in the temperature range of 39-79 °C in C6D6. Activation parameters for this reaction are ΔH⧧ = 15.8 ± 2.0 kcal·mol-1 and ΔS⧧ = -28.5 ± 5 cal·mol-1·K-1 for 1Ph and ΔH⧧ = 22.7 ± 2.5 kcal·mol-1 and ΔS⧧ = -12.4 ± 6 cal·mol-1·K-1 for 1Cy. Addition of O2, CO2, N2O, or PPh3 to sealed tube NMR experiments did not alter in a detectable way the rate or product distribution of the reactions. Computational DFT studies of elimination of hyponitrite from trans-Me3Sn-O-N═N-O-SnMe3 (1Me) yield a mechanism involving initial migration of the R3Sn group from O to N passing through a marginally stable intermediate product and subsequent N2O elimination. Reactions of 1Ph with protic acids HX are rapid and lead to formation of R3SnX and trans-H2N2O2. Reaction of 1Ph with the metal radical •Cr(CO)3C5Me5 at low concentrations results in rapid evolution of N2O. At higher •Cr(CO)3C5Me5 concentrations, evolution of CO2 rather than N2O is observed. Addition of 1 atm or less CO2 to benzene or toluene solutions of 2Ph and 2Cy resulted in very rapid reaction to form the corresponding carbonates R3Sn-O-C(═O)-O-SnR3 (R = Ph (3Ph) and R = Cy (3Cy)) at room temperature. Evacuation results in fast loss of bound CO2 and regeneration of 2Ph and 2Cy. Variable temperature data for formation of 3Cy yield ΔHo = -8.7 ± 0.6 kcal·mol-1, ΔSo = -17.1 ± 2.0 cal·mol-1·K-1, and ΔGo298K = -3.6 ± 1.2 kcal·mol-1. DFT studies were performed and provide additional insight into the energetics and mechanisms for the reactions.

Collisions in a dual-species magneto-optical trap of molecules and atoms

We study inelastic collisions between CaF molecules and 87Rb atoms in a dual-species magneto-optical trap. The presence of atoms increases the loss rate of molecules from the trap. By measuring the loss rates and density distributions, we determine a collisional loss rate coefficient k 2 = (1.43 ± 0.29) × 10−10 cm3 s−1 at a temperature of 2.4 mK. We show that this is not substantially changed by light-induced collisions or by varying the populations of excited-state atoms and molecules. The observed loss rate is close to the universal rate expected in the presence of fast loss at short range, and can be explained by rotation-changing collisions in the ground electronic state.

Targeting PRMT1 As a Novel Curative Therapy for Acute Myeloid Leukemia

Protein arginine methyltransferase 1 (PRMT1) is dynamically regulated in normal hematopoiesis and constitutively high expression of PRMT1 is associated with low survival rate in acute myeloid leukemia (AML) (Zhang et al. 2015). PRMT1 has been demonstrated for maintaining cell proliferation of AML1-ETO, MLL fusion initiated AML. Therefore, targeting PRMT1 may be a novel curative therapy for AML. In this report, we will use leukemia mouse models to address how to target protein arginine methyltransferase 1 as a novel therapy for treating acute megakaryocytic leukemia (AMKL).Pediatric AMKL is a fatal disease with poor prognosis. So far chemotherapy is still the first line therapy for AMKL, yet gene-specific therapy is not available. Chromosomal translocation t(1;22)(p13;q13), which generates the fusion protein RBM15-MKL1 (aka OTT-MAL), is exclusively found in pediatric AMKL patients. Knock-in mice that express Rbm15-MKL1 from endogenous Rbm15 locus develops leukemia with low penetrance and long latency, suggesting that additional genetic or epigenetic changes are required for the rapid leukemia progression. Previous study by Mercher et al. showed that addition of mutant thrombopoietin receptor tyrosine kinase c-MPLW515L to Rbm15-MKL1 translocation leads to aggressive leukemia development in mice. We further demonstrated that forced PRMT1 expression bypassed the need for c-MPLW515L to allow Rbm15-MKL1 cells to proliferate in a cytokine-independent fashion in cell culture. Viability of PRMT1-expressing cells as well as the c-MPLW515L expressing cells is highly sensitive to the treatment of the PRMT1 inhibitor MS203, indicating that the survival of transformed cells is dependent on PRMT1. Co-expression of PRMT1 and Rbm15-MKL1 in cord blood cells can sustain the long term culture while RBM15-MKL1 expressing cord blood cells will die quickly. Based on these results, we rationalize that PRMT1 is a key factor that cooperates with Rbm15-MKL1 to mediate malignant transformation and aggressive leukemia development. Inhibition of PRMT1 activity would have therapeutic effect on OTT-MAL-initiated leukemia. In this vein, we administered daily i.p. injection of PRMT1 inhibitor to mice that were transferred either c-MPLW515L- or PRMT1-expressing Rbm15-MKL1 cells. Inhibitor-treated group has greatly improved survival time. Vehichle-treated mice suffered from fast weight loss, early disease onset and then died within 21-23 days post transplantation while most inhibitor-treated mice remained alive with stable body weight. PRMT1 inhibitor treatment significantly blocks leukemia-associated splenomegaly. Flow cytometry analysis showed that inhibitor-treated mice have notably less leukemia cells in bone marrow and in peripheral blood, compared to their control counterparts. More than half of control mice developed rear limb paralysis and visible blood clots were found on their spine upon dissection. Two and four weeks post the last injection we analyzed the peripheral blood of surviving inhibitor-treated mice to detect residual disease and found that the percentage of leukemic cells was very low, in some cases completely undetectable. Up to 3 months those mice remained healthy and no signs of relapse without further MS203 treatment. How the PRMT1 inhibitor MS203 blocks leukemia progression with PDX models of Down syndrome AMKL will be presented.At the molecular level, we performed metabolomics analysis with mass spectrometry and Seahorse analyzer, and discovered that PRMT1 reprogrammed metabolism in leukemia cells through upregulation of glycolysis pathway and downregulation of fatty acid oxidation pathway. We reported that PRMT1 controls RBM15 protein stability by triggering methylation-dependent ubiquitilation (Zhang et al. 2015). In this report, we further demonstrated that RBM15 is directly responsible for controlling the mRNA stability of key metabolic enzymes. Thus we reasoned that the PRMT1-RBM15 axis is a key axis in controlling metabolism during leukemia progression. Based on these findings, we further tested whether we can use weight-controlling drugs such as etomoxir for treating leukemia. In summary, copious expression of PRMT1 in AML makes PRMT1 an encouraging new target for curative therapy, The PRMT1 inhibitor MS203 which has few side effects in mice will be a strong candidate for future clinical trials. DisclosuresNo relevant conflicts of interest to declare.

A Functional PEO/LiTFSI-Coated Coated Separator for Electrochemical Lithium-Sulfur Battery

There is a strong interest in exploring next-generation rechargeable batteries that can deliver a high energy density for a long cycle life and a long shelf time at an affordable cost. The commercial lithium-ion battery systems have exhibited the advantages in satisfying all the above-mentioned requirements so that the lithium-ion technology has dominated the battery business for over 30 years. To obtain further upgrades in battery technologies, the current lithium-ion systems based on various lithium-insertion oxide cathodes are mature techniques and have faced the theoretical values in terms of their capacity and energy density values. Moreover, the increasing demands of commercial lithium-ion batteries have encountered the increasing prices and limited availability of the raw materials. To address these issues, the conversion-reaction cathodes featuring an enhanced energy density at an affordable cost garner significant attention.Sulfur cathodes have become appealing as they offer an order of magnitude higher capacity and are abundant. The electrochemical conversion reactions of sulfur with lithium ions provide lithium sulfide, involving two electrons per sulfur and providing a high charge-storage capacity of 1,672 mA∙h g-1. The high-capacity sulfur cathodes enable the packaged lithium-sulfur cells to attain 2-3 times higher energy density than that offered by the current lithium-ion batteries. However, several challenges prevent the practical application of lithium-sulfur batteries. The high resistivity of solid-state sulfur and its end-discharged lithium sulfides as well as the dissolution and diffusion of intermediate liquid-state lithium polysulfides cause the poor electrochemical utilization of sulfur, fast capacity fade, and low Coulombic efficiency of the cell in a short cycle life.Significant improvements have been made in the modification of the material and the structure of the sulfur cathodes and the separators in recent years. This presentation will focus on lithium-sulfur battery separator with a coating layer of mixtures containing poly(ethylene oxide) (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) on a polypropylene membrane, forming a functional gel polymer electrolyte (GPE) / separator composite. The PEO/LiTFSI-coated polypropylene membrane is configurated to face the sulfur cathode and functions as the restrict film to cease the fast diffusion of liquid-state polysulfides and to stabilize the liquid-state active materials within the cathode region of the cell as the catholyte for enhancing the electrochemical reaction kinetics and stability. As a result, our findings show that the lithium-sulfur cells with the PEO/LiTFSI-coated polypropylene membrane show a high discharge capacity of 1,200 mA∙h g-1, a long cycle life of 200 cycles, and high Coulombic efficiency of above 99%. As a comparison, the same cell with a PEO-coated polypropylene membrane reveals a poor electrochemical utilization and efficiency due to the lack of LiTFSI as the ion-diffusion matrix, resulting in low discharge capacity of 662 mA∙h g-1and poor capacity retention. On the other hand, the same cell with a regular unmodified separator membrane suffers the fast loss of the liquid-state active material, showing a short cycle life of less than 100 cycles. According to the material analysis and electrochemical comparison, the PEO/LiTFSI-coated polypropylene membrane proves its capability in blocking the uncontrolled migration of polysulfides, while allowing the smooth diffusion of lithium ions. In conclusion, our experimental and analytical results prove the PEO/LiTFSI-coated polypropylene membrane as an advanced and a facile separator design in the development of high-loading/content sulfur cathodes in lithium-sulfur batteries for realizing a high energy density.

The Recognition of Excessive blood loss At ChildbirTh (REACT) Study: a two-phase exploratory, sequential mixed methods inquiry using focus groups, interviews and a pilot, randomised crossover study.

To explore how childbirth-related blood loss is evaluated and excessive bleeding recognised; and to develop and test a theory of postpartum haemorrhage (PPH) diagnosis. Two-phase, exploratory, sequential mixed methods design using focus groups, interviews and a pilot, randomised crossover study. Two hospitals in North West England. Women (following vaginal birth with and without PPH), birth partners, midwives and obstetricians. Phase 1 (qualitative): 8 focus groups and 20 one-to-one, semi-structured interviews were conducted with 15 women, 5 birth partners, 11 obstetricians, 1 obstetric anaesthetist and 19 midwives (n=51). Phase 2 (quantitative): 11 obstetricians and ten midwives (n=21) completed two simulations of fast and slow blood loss using a high-fidelity childbirth simulator. Responses to blood loss were described as automatic, intuitive reactions to the speed, nature and visibility of blood flow. Health professionals reported that quantifying volume was most useful after a PPH diagnosis, to validate intuitive decisions and guide ongoing management. During simulations, PPH treatment was initiated at volumes at or below 200ml (fast mean blood loss 79.6ml, SD 41.1; slow mean blood loss 62.6ml, SD 27.7). All participants treated fast, visible blood loss, but only half treated slow blood loss, despite there being no difference in volumes (difference 18.2ml, 95% CI -5.6 to 42.2ml, P=0.124). Experience and intuition, rather than blood loss volume, inform recognition of excessive blood loss after birth. Women and birth partners want more information and open communication about blood loss. Further research exploring clinical decision-making and how to support it is required. During a PPH, clinical decision-making is intuitive with clinicians treating as soon as excessive loss is recognised.

Controlling Charge Carrier Trapping and Recombination in BiVO4 with the Oxygen Vacancy Oxidation State.

The lack of an in-depth understanding of the intrinsic oxygen vacancy (OV) defect properties in the photoanode BiVO4 limits the further improvement of its photoelectrochemical water splitting performance. To address this issue, nonadiabatic molecular dynamics simulations are performed to study the impact of OV on charge carrier lifetimes in BiVO4. The simulations show that a neutral OV gives rise to local structural distortions due to the formation of V-O-V bonds, forcing the electrons trapped on the nearer of the two V atoms to form two deep polaron-like V4+ hole traps. These localized midgap states greatly accelerate nonradiative electron-hole recombination compared to that of pristine BiVO4, reaching a time scale of several nanoseconds in good agreement with experiments. The ionized OV state restores the bandgap to its value in pristine BiVO4 and restores the charge carrier lifetimes due to the fast loss of coherence time. Our study reveals the mechanism of the detrimental role of OV in BiVO4 and provides valuable insights for improving the performance of the BiVO4 photoanode by ionizing the oxygen vacancy.

Critical range of soil organic carbon in southern Europe lands under desertification risk

Soil quality is fundamental for ecosystem long term functionality, productivity and resilience to current climatic changes. Despite its importance, soil is lost and degraded at dramatic rates worldwide. In Europe, the Mediterranean areas are a hotspot for soil erosion and land degradation due to a combination of climatic conditions, soils, geomorphology and anthropic pressure. Soil organic carbon (SOC) is considered a key indicator of soil quality as it relates to other fundamental soil functions supporting crucial ecosystem services. In the present study, the functional relationships among SOC and other important soil properties were investigated in the topsoil of 38 sites under different land cover and management, distributed over three Mediterranean regions under strong desertification risk, with the final aim to define critical SOC ranges for fast loss of important soil functionalities. The study sites belonged to private and public landowners seeking to adopt sustainable land management practices to support ecosystem sustainability and productivity of their land. Data showed a very clear relationship between SOC concentrations and the other analyzed soil properties: total nitrogen, bulk density, cation exchange capacity, available water capacity, microbial biomass, C fractions associated to particulate organic matter and to the mineral soil component and indirectly with net N mineralization. Below 20 g SOC kg−1, additional changes of SOC concentrations resulted in a steep variation of all the analyzed soil indicators, an order of magnitude higher than the changes occurring between 50 and 100 g SOC kg−1 and 3–4 times the changes observed at 20–50 g SOC kg−1. About half of the study sites showed average SOC concentration of the topsoil centimetres <20 g SOC kg−1. For these areas the level of SOC might hence be considered critical and immediate and effective recovery management plans are needed to avoid complete land degradation in the next future.

The influence of current density, rest time and electrolyte composition on the self-discharge of organic radical polymers

In this work we report a systematic study about the influence of the charging current density and the rest time on the self-discharge of poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA) based electrodes in two model electrolytes, namely 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI, IL) and 1 M Pyr14TFSI in propylene carbonate (PC). We show that for each electrolyte it is possible to identify a threshold of current density (and thus C-rate) which can be safely applied without increasing the electrode self-discharge. Furthermore, we show that the self-discharge of the PTMA-based electrodes is originated by a combination of activation controlled faradic processes, charge redistribution and diffusion limited processes. The use of current densities above the threshold is causing an improper charging process, which leads to faradic reactions on the surface of the eletrode followed by the redistribution of charge on the surface of the electrodes and causes a fast energy loss when a current is no longer applied. When current densities below the threshold are used, the diffusion of redox shuttles becomes the driving force of self-discharge taking place in PTMA based electrodes.

Naphthalenothiophene imide-based polymer exhibiting over 17% efficiency

Summary Developing novel electron-deficient monomers is crucially important for the future development of non-fullerene organic solar cells. Here, we report a new electron-deficient monomer naphthalenothiophene imide (NTI) and NTI-based copolymers PNTB and PNTB-2T. The strong electron-withdrawing ability of NTI could effectively lower the HOMO level of the polymer that facilitates the tuning of the polymer’s physical properties while simultaneously maintaining the low-lying HOMO value. Polymer chains modification by introducing extra thiophenes results in the closed π−π stacking and ordered polymer chain packing of PNTB-2T and is proven to be an effective strategy to increase the device performance. Thus, solar cell devices for PNTB-2T:Y6 exhibit an efficiency of 16.72%, which is further enhanced to 17.35% by the third component PC71BM, whereas that for PNTB:Y6 is only 3.81%. Importantly, PNTB-2T-based devices exhibit excellent batch-to-batch reproducibility. These features make this family of polymer donors very promising and the design strategies will enlighten future development of high-performance polymer donors for organic solar cells (OSC).

Surface plasmon polaritons broadband band-stop filter based on EIT effect modulation

The filter is one of the most important key elements of electronic circuit. With the rapid development of information, traditional electrical filters can no longer meet the requirements of fast information processing speed and low loss. All optical information processing is considered as one of the solutions to solve this problem. Therefore, there is great significance for studying the all-optical filter. Here, we put forward a kind of broadband band-stop filter which based on surface plasmon polaritons (SPPs) metal - insulator - metal (MIM) modulating by electromagnetically induced transparency (EIT) resonance. We use the finite element method for numerical simulation, and further research on the factors influencing the transmission characteristics of this structure by adjusting the geometric structure. Compared with similar SPPs-based filters, the proposed structure realizes broad stopband, and we can change the EIT resonance to modulate the band-stop filter wavelength range. The proposed broadband band-stop filter based on EIT effect modulation may have great potential in the next generation of all-optical information processing and communication.

Quasilinear critical gradient model for Alfven eigenmode driven energetic particle transport with intermittency

A simplified quasilinear critical gradient model (QLCGM) for Alfven eigenmode (AE) driven energetic particle (EP) transport is used to treat the intermittency (burstiness) of the transport. Here intermittency is defined as the ratio of the root mean square deviation from mean flow to the mean flow. The model posits that the intermittency results from the micro-turbulent noise induced in the thermal plasma damping rate for the AE. The model is embedded in a time-dependent EP density transport code to generate the transport-flow time traces from typical critical gradient and slowing down density profiles. The QLCGM appears to be in reasonable agreement with the level and characteristics of the intermittency observed in the DIII-D fast particle loss detector flow time traces: high kurtosis [O(40)] of the burstiness with the intermittency O(1–2) increasing with the level of mean flow.

Widely targeted metabolomics analysis reveals new biomarkers and mechanistic insights on chestnut (Castanea mollissima Bl.) calcification process

Chestnut calcification is a quality deterioration due to fast water loss, which has been of deep concern for chestnut quality control because its mechanism is unclear. In order to find out the different key metabolites and metabolic pathways related to the occurrence of chestnut calcification, in this study, liquid chromatography-tandem mass spectrometry (LC-MS/MS) based widely targeted metabolomics analysis was performed on chestnuts that were stored at 50%–55% (low relative humidity, LRH) at 25 °C and 85%–90% (high relative humidity, HRH) at 25 °C. A total of 611 metabolites were detected, and 55 differentially accumulated metabolites were identified as key metabolites involved in chestnut calcification process. The decrease in some monosaccharides accompanied with the increase in some unsaturated fatty acids indicated the degradation of chestnut cell wall and cell membrane during calcification process. As a stress response, amino acid metabolism related to membrane stability was significantly activated. In addition, the enhancement of phenylpropanoid biosynthesis pathway and flavonoid biosynthesis pathway characterized by the accumulation of lignin precursors and antioxidants suggested that lignification process was triggered in calcified chestnut. Therefore, the degradation and hardening of the cell wall and membrane damage were proposed to be associated with the calcification occurrence of chestnut. The metabolic profile of chestnut characterized in this study provided new insights into chestnut calcification process and laid a foundation for further chestnut quality control.