Abstract
We present the fourth Open Gravitational-wave Catalog (4-OGC) of binary neutron star (BNS), binary black hole (BBH), and neutron star–black hole (NSBH) mergers. The catalog includes ...observations from 2015 to 2020 covering the first through third observing runs (O1, O2, O3a, and O3b) of Advanced LIGO and Advanced Virgo. The updated catalog includes seven BBH mergers that were not previously reported with high significance during O3b for a total of 94 observations: 90 BBHs, 2 NSBHs, and 2 BNSs. The most confident new detection, GW200318_191337, has component masses
49.1
−
12.0
+
16.4
M
⊙
and
31.6
−
11.6
+
12.0
M
⊙
;
its redshift of
0.84
−
0.35
+
0.4
(90% credible interval) may make it the most distant merger so far. We estimate the merger rate of BBH sources, assuming a power-law mass distribution containing an additive Gaussian peak, to be
16.5
−
6.2
+
10.4
(
25.0
−
8.0
+
12.6
)
Gpc
−3
yr
−1
at a redshift of
z
= 0 (0.2). For BNS and NSBH sources, we estimate a merger rate of
200
−
148
+
309
Gpc
−3
yr
−1
and
19
−
14
+
30
Gpc
−3
yr
−1
, respectively, assuming the known sources are representative of the total population. We provide reference parameter estimates for each of these sources using an up-to-date model accounting for instrumental calibration uncertainty. The corresponding data release also includes our full set of subthreshold candidates.
Lithium-oxygen cells have attracted extensive interests due to their high theoretical energy densities. The main challenges are the low round-trip efficiency and cycling instability over long time. ...However, even in the state-of-the-art lithium-oxygen cells the charge potentials are as high as 3.5 V that are higher by 0.70 V than the discharge potentials. Here we report a reaction mechanism at an oxygen cathode, ruthenium and manganese dioxide nanoparticles supported on carbon black Super P by applying a trace amount of water in electrolytes to catalyse the cathode reactions of lithium-oxygen cells during discharge and charge. This can significantly reduce the charge overpotential to 0.21 V, and results in a small discharge/charge potential gap of 0.32 V and superior cycling stability of 200 cycles. The overall reaction scheme will alleviate side reactions involving carbon and electrolytes, and shed light on the construction of practical, rechargeable lithium-oxygen cells.
The detrimental shuttle effect in lithium–sulfur batteries mainly results from the mobility of soluble polysulfide intermediates and their sluggish conversion kinetics. Herein, presented is a ...multifunctional catalyst with the merits of strong polysulfides adsorption ability, superior polysulfides conversion activity, high specific surface area, and electron conductivity by in situ crafting of the TiO2‐MXene (Ti3C2Tx) heterostructures. The uniformly distributed TiO2 on MXene sheets act as capturing centers to immobilize polysulfides, the hetero‐interface ensures rapid diffusion of anchored polysulfides from TiO2 to MXene, and the oxygen‐terminated MXene surface is endowed with high catalytic activity toward polysulfide conversion. The improved lithium–sulfur batteries deliver 800 mAh g−1 at 2 C and an ultralow capacity decay of 0.028% per cycle over 1000 cycles at 2 C. Even with a high sulfur loading of 5.1 mg cm−2, the capacity retention of 93% after 200 cycles is still maintained. This work sheds new insights into the design of high‐performance catalysts with manipulated chemical components and tailored surface chemistry to regulate polysulfides in Li–S batteries.
An in situ built TiO2‐MXene heterostructure through partial oxidation of Ti3C2Tx
nanosheets combines the advantages of large surface area, strong polysulfides capturing ability, high electrocatalytic activity, and conductivity, which enable enhanced capture and catalytic conversion of polysulfides. Consequently, high sulfur mass loading (5.1 mg cm−2) cathodes with heterostructure‐graphene interlayers deliver high sulfur utilization and stable cycling performance.
Solid-state lithium batteries are flourishing due to their excellent potential energy density. Substantial efforts have been made to improve their electrochemical performance by increasing the ...conductivity of solid-state electrolytes (SEs) and designing a compatible battery configuration. The safety of a solid lithium battery has generally been taken for granted due to the nonflammability and strength of SEs. However, recent results have shown the release of dangerous gases and intense heat due to the formation of lithium dendrites, indicating the safety of solid-state lithium batteries may have been overestimated. In this review, we introduce a safety evaluation methodology, then focus on the garnet Li7La3Zr2O12 (LLZO) and sulfide-based SEs, summarizing their structure, conductivity, compatibility with a lithium metal anode, electrochemical/chemical stability, and mechanical/thermal stability, which correlate closely with battery safety. We also evaluate the safety of all-solid-state lithium batteries, then conclude by discussing future avenues for improving the safety of SE-based batteries.
Display omitted
•The overlooked safety issues of solid-state batteries are highlighted.•The coupling between the safety of solid-state batteries and properties of solid-state electrolytes is discussed.•The safety of solid-state full lithium batteries is considered.•Strategies for safety improvement and studying battery safety in accident situations are proposed.
Large energy is required for traditional CO2 fixation, leading to more CO2 emission and additional pollutants. Recently, integrating renewable energy with CO2 fixation has attracted increasing ...attention as a sustainable strategy. Here, based on a systematic investigation on aprotic Li-CO2 electrochemistry, we first provide an alternative strategy for either CO2 fixation or energy storage. Both strategies share the same CO2 reduction process with the formation of Li2CO3 and carbon. Subsequently, CO2 fixation is achieved through a rechargeable/irreversible oxidation process, during which Li2CO3 is decomposed, while the carbon obtained remains fixed. Moreover, a reversible Li-CO2 battery system has been realized based on co-oxidization of the resulting carbon and Li2CO3 using a Ru catalyst. Consequently, by shedding light on the fundamental reaction mechanism of aprotic Li-CO2 electrochemistry, the proof of concept presented here provides strong theoretical underpinning for developing flexible routes for both CO2 fixation and Li-CO2 energy storage.
Display omitted
•Provide deeper insight into the mechanism of aprotic Li-CO2 electrochemistry•Build a new strategy for CO2 electrochemical fixation into carbon•Design a flexible route for both CO2 fixation and a reversible Li-CO2 battery
As one of the predominant greenhouse gases, fixing carbon dioxide (CO2) is one of the major global challenges. Although substantial efforts have been made to fix and utilize CO2 through various methodologies, achievement of CO2 fixation into other chemicals still requires a large input of energy, inevitably leading to additional pollution. Therefore, utilizing a reversible battery system for renewable energy storage in a cost-effective and eco-friendly CO2 fixation strategy would be an ideal model. Here, we first provide a new strategy for CO2 fixation through a rechargeable/irreversible Li-CO2 electrochemical technology. More revolutionary, turning the originally irreversible process into a reversible cycle by the use of a specific precious metal catalyst, the newly proposed CO2 fixation strategy could further evolve into an energy storage technique in which CO2 acts as an energy carrier to store and release renewable energy.
Based on a systematic investigation on aprotic Li-CO2 electrochemistry, we design a flexible strategy for either CO2 fixation or energy storage. Typically, CO2 can be fixed into carbon species through a rechargeable/irreversible electrochemical process. Moreover, using a specific catalyst, the aprotic Li-CO2 battery system can be realized via a reversible cycle. The proof of concept revealed in this study provides strong theoretical support for the practical design of both CO2 fixation techniques and renewable energy storage devices.
The development of aprotic Li‐O2 batteries, which are promising candidates for high gravimetric energy storage devices, is severely limited by superoxide‐related parasitic reactions and large voltage ...hysteresis. The fundamental reaction pathway of the aprotic Li‐O2 battery can be altered by the addition of water, which changes the discharge intermediate from superoxide (O2−) to hydroperoxide (HO2−). The new mechanism involving HO2− intermediate realizes the two‐electron transfer through a single step, which significantly suppresses the superoxide‐related side reactions. Moreover, addition of water also triggers a solution‐based pathway that effectively reduces the voltage hysteresis. These discoveries offer a possible solution for desirable Li‐O2 batteries free of aggressive superoxide species, highlighting the design strategy of modifying the reaction pathway for Li‐O2 electrochemistry.
By altering aggressive superoxide (O2−) to moderate hydroperoxide (HO2−), addition of water effectively controls the side reactions during oxygen reduction. The reversible oxygen–peroxide redox reaction guarantees a low overpotential, which is superior to the electrochemistry occurring on the cathode/Li2O2 interface. The positive effect of water on both discharge and charge can remedy the inherent defects in aprotic Li‐O2 batteries.
Causing more and more deaths, stroke has been a leading cause of death worldwide. However, success in clinical stroke trials has remained elusive. N-oleoylethanolamine (OEA) was an endogenous highly ...hydrophobic molecule with outstanding neuroprotective effect. In this article, hydrogen bonds were successfully formed between OEA and soybean phosphatidylcholine (SPC). The synthetic OEA-SPC complex and DSPE-PEG were self-assembled into liposomes (OEA NPs), with OEA-SPC loaded in the core and PEG formed a hydrophilic shell. Hence, highly hydrophobic OEA was loaded into liposomes as amorphous state with a drug loading of 8.21 ± 0.18 wt%. With fairly uniform size and well-distributed character, the OEA NPs were systemically assessed as an intravenous formulation for stroke therapy. The results indicated that the administration of OEA NPs could significantly improve the survival rate and the Garcia score of the MCAO rats compared with free OEA. The TTC-stained brain slices declared that the cerebral infarct volume and the edema degree induced by MCAO could be decreased to an extremely low level via the administration of OEA NPs. The Morris water maze (MWM) test suggested that the spatial learning and memory of the MCAO rats could also be ameliorated by OEA NPs. The immunofluorescence assay stated that the apoptosis of the neurons and the inflammation within the brain were greatly inhibited. The results suggest that the OEA NPs have a great chance to develop OEA as a potential anti-stroke formulation for clinic application.
Due to the lack of research on the pathological mechanism of temporomandibular joint osteoarthritis (TMJOA), there are few effective treatment measures in the clinic. In recent years, microRNAs ...(miRs) have been demonstrated to play an important role in the pathogenesis of osteoarthritis (OA) by regulating a variety of target genes, and the latest evidence shows that miR-21-5p is specifically overexpressed in OA. The purpose of this project was to clarify whether miR-21-5p can regulate the TMJOA process by targeting Spry1.
TMJOA was induced by a unilateral anterior crossbite (UAC) model, and the effect of miR-21-5p knockout on TMJOA was evaluated by toluidine blue (TB), immunohistochemical (IHC) staining, Western blotting (WB) and RT-qPCR. Primary mouse condylar chondrocytes (MCCs) were isolated, cultured and transfected with a series of mimics, inhibitors, siRNA-Spry1 or cDNA Spry1. WB, RT-qPCR, IHC and TB were used to detect the effect of miR-21-5p and its target gene Spry1 on the expression of MMP-13, VEGF and p-ERK1/2 in TMJOA. The effect of miR-21-5p on angiogenesis was evaluated by chick embryo chorioallantoic membrane (CAM) assay and WB.
In the UAC model, the cartilage thickness and extracellular matrix of miR-21-5p knockout mice were less damaged, and miR-21-5p and UAC model were shown to affect the expression of Spry1, IL-1β, MMP-13, and VEGF. Luciferase experiments confirmed that Spry1 was the direct target of miR-21-5p. The expression levels of Spry1, MMP-13, VEGF and p-ERK1/2 in MCCs transfected with miR-21-5p mimic were higher than those in the inhibitor group. Under the simulated inflammatory environment of IL-1β, the expression levels of MMP-13, VEGF and p-ERK1/2 were positively correlated with miR-21-5p, while Spry1 was negatively correlated with miR-21-5p. Inhibition of miR-21-5p expression and overexpression of Spry1 enhanced the inhibition of MMP-13, VEGF and p-ERK1/2 expression. MiR-21-5p had a significant role in promoting angiogenesis in the chick embryo CAM assay, and this role was clearly mediated by the ERK-MAPK signalling pathway.
This study verified that miR-21-5p can promote the process of TMJOA by targeting Spry1, which provides a new direction for future research on the treatment of this disease.
Abstract
Over the course of the third observing run of the LIGO–Virgo–KAGRA Collaboration, several gravitational-wave (GW) neutron star–black hole (NSBH) candidates have been announced. By assuming ...that these candidates are real signals with astrophysical origins, we analyze the population properties of the mass and spin distributions for GW NSBH mergers. We find that the primary BH mass distribution of NSBH systems, whose shape is consistent with that inferred from the GW binary BH (BBH) primaries, can be well described as a power law with an index of
α
=
4.8
−
2.8
+
4.5
plus a high-mass Gaussian component peaking at
∼
33
−
9
+
14
M
⊙
. The NS mass spectrum could be shaped as a nearly flat distribution between ∼1.0 and 2.1
M
⊙
. The constrained NS maximum mass agrees with that inferred from NSs in our Galaxy. If GW190814 and GW200210 are NSBH mergers, the posterior results of the NS maximum mass would be always larger than ∼2.5
M
⊙
and significantly deviate from that inferred in Galactic NSs. The effective inspiral spin and effective precession spin of GW NSBH mergers are measured to potentially have near-zero distributions. The negligible spins for GW NSBH mergers imply that most events in the universe should be plunging events, which support the standard isolated formation channel of NSBH binaries. More NSBH mergers to be discovered in the fourth observing run would help to more precisely model the population properties of cosmological NSBH mergers.
PDF
