Hydride ion (H-) transport behavior in barium hydride under high pressure.

Hydride ions (H-) have an appropriate size for fast transport, which makes the conduction of H- attractive. In this work, the H- transport properties of BaH2 have been investigated under pressure using in situ impedance spectroscopy measurements up to 11.2 GPa and density functional theoretical calculations. The H- transport properties, including ionic migration resistance, relaxation frequency, and relative permittivity, change significantly with pressure around 2.3 GPa, which can be attributed to the structural phase transition of BaH2. The ionic migration barrier energy of the P63/mmc phase decreases with pressure, which is responsible for the increased ionic conductivity. A huge dielectric constant at low frequencies is observed, which is related to the polarization of the H- dipoles. The current study establishes general guidelines for developing high-energy storage and conversion devices based on hydride ion transportation.

Self-Trapped Interlayer Excitons in van der Waals Heterostructures.

The self-trapped state (STS) of the interlayer exciton (IX) has aroused enormous interest owing to its significant impact on the fundamental properties of the van der Waals heterostructures (vdWHs). Nevertheless, the microscopic mechanisms of STS are still controversial. Herein, we study the corrections of the binding energies of the IXs stemming from the exciton-interface optical phonon coupling in four kinds of vdWHs and find that these IXs are in the STS for the appropriate ratio of the electron and hole effective masses. We show that these self-trapped IXs could be classified into type I with the increasing binding energy in the tens of millielectronvolts range, which are very agreement with the red-shift of the IX spectra in experiments, and type II with the decreasing binding energy, which provides a possible explanation for the blue-shift and broad line width of the IX's spectra at low temperatures. Moreover, these two types of exciton states could be transformed into each other by adjusting the structural parameters of vdWHs. These results not only provide an in-depth understanding for the self-trapped mechanism but also shed light on the modulations of IXs in vdWHs.

Tuning 4f-Center Electron Structure by Schottky Defects for Catalyzing Li Diffusion to Achieve Long-Term Dendrite-Free Lithium Metal Battery.

Lithium metal is considered as the most prospective electrode for next-generation energy storage systems due to high capacity and the lowest potential. However, uncontrollable spatial growth of lithium dendrites and the crack of solid electrolyte interphase still hinder its application. Herein, Schottky defects are motivated to tune the 4f-center electronic structures of catalysts to provide active sites to accelerate Li transport kinetics. As experimentally and theoretically confirmed, the electronic density is redistributed and affected by the Schottky defects, offering numerous active catalytic centers with stronger ion diffusion capability to guide the horizontal lithium deposition against dendrite growth. Consequently, the Li electrode with artificial electronic-modulation layer remarkably decreases the barriers of desolvation, nucleation, and diffusion, extends the dendrite-free plating lifespan up to 1200 h, and improves reversible Coulombic efficiency. With a simultaneous catalytic effect on the conversions of sulfur species at the cathodic side, the integrated Li-S full battery exhibits superior rate performance of 653 mA h g-1 at 5 C, high long-life capacity retention of 81.4% at 3 C, and a high energy density of 2264 W h kg-1 based on sulfur in a pouch cell, showing the promising potential toward high-safety and long-cycling lithium metal batteries.

VerSe: A Vertebrae labelling and segmentation benchmark for multi-detector CT images.

Vertebral labelling and segmentation are two fundamental tasks in an automated spine processing pipeline. Reliable and accurate processing of spine images is expected to benefit clinical decision support systems for diagnosis, surgery planning, and population-based analysis of spine and bone health. However, designing automated algorithms for spine processing is challenging predominantly due to considerable variations in anatomy and acquisition protocols and due to a severe shortage of publicly available data. Addressing these limitations, the Large Scale Vertebrae Segmentation Challenge (VerSe) was organised in conjunction with the International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI) in 2019 and 2020, with a call for algorithms tackling the labelling and segmentation of vertebrae. Two datasets containing a total of 374 multi-detector CT scans from 355 patients were prepared and 4505 vertebrae have individually been annotated at voxel level by a human-machine hybrid algorithm (https://osf.io/nqjyw/, https://osf.io/t98fz/). A total of 25 algorithms were benchmarked on these datasets. In this work, we present the results of this evaluation and further investigate the performance variation at the vertebra level, scan level, and different fields of view. We also evaluate the generalisability of the approaches to an implicit domain shift in data by evaluating the top-performing algorithms of one challenge iteration on data from the other iteration. The principal takeaway from VerSe: the performance of an algorithm in labelling and segmenting a spine scan hinges on its ability to correctly identify vertebrae in cases of rare anatomical variations. The VerSe content and code can be accessed at: https://github.com/anjany/verse.

High-pressure crystal structure and properties of BrCl.

The pressure-induced phase transitions of bromine chloride (BrCl) were studied using the CALYPSO structure prediction method and first-principles calculations. Geometry optimization showed that the BrCl underwent the following phase transitions under high pressure: Cmcm → C2/m → Fddd → P4/mmm. These phase transitions occurred at 75, 94, and 140 GPa, respectively. All four phases were calculated to be dynamically stable, judging by the absence of any imaginary phonon modes in the whole Brillouin zone. As the pressure increased, the number of bonds between Br atom and surrounding Cl atoms increased. The high-pressure P4/mmm-BrCl phase (stable at 150 GPa) consisted of eight-coordinated Br atoms and is predicted to exist in BrCl compounds for the first time. The band overlap of the Cmcm phase, which caused the pressure-induced semiconductor → metal transition, occurs ∼50 GPa. This article lays the foundation for further theoretical and experimental research.

Two cyclotriveratrylene metal-organic frameworks as effective catalysts for Knoevenagel condensation and CO2 cycloaddition with epoxides.

By using a novel imidazole-functional cyclotriveratrylene ligand, two isostructural frameworks, [Cd3(HECTV)(bdc)3]·DMF·6H2O (1) and [Zn3(HECTV)(OH-bdc)3]·3DMF·4H2O (2) (HECTV = 5,6,12,13,19,20-hexaimidazolium-ethoxy-cyclotriveratrylene), were constructed. The two compounds exhibit fascinating 4-fold interpenetration three-dimensional frameworks. There are still large void spaces in the structures despite the interpenetration, which were filled with solvent molecules. Interestingly, 1 demonstrates a single-crystal to single-crystal transformation with the guests changed by a cycloalkane solvent. Strikingly, 1 and 2 feature highly heterogeneous catalytic activities for Knoevenagel condensation and CO2 cycloaddition, respectively. In particular, catalysts 1 and 2 could be reused with good catalytic performance.

Clinical efficacy of oral ganciclovir for prophylaxis and treatment of recurrent herpes simplex keratitis.

BACKGROUND: Herpes simplex keratitis (HSK) caused by herpes simplex virus 1 (HSV-1), which has high recurrent rate and incidence of severe vision loss, is the leading cause of infectious blindness in the world. The aim was to explore the clinical efficacy of oral ganciclovir (GCV) in the prevention of recurrent HSK. METHODS: A multicenter, prospective, randomized, single-blind, and controlled clinical trial was conducted from April 2010 to June 2013. One hundred seventy-three patients (173 eyes involved) who were diagnosed as recurrent HSK definitely, including stromal keratitis and corneal endotheliitis, were divided into three groups randomly: negative control (placebo) group was topically administered with 0.15% GCV ophthalmic gel, 4 times per day and 0.1% fluorometholone eye drops, 3 times per day until resolution of HSK; positive control acyclovir (ACV) group was topically adopted the same ophthalmic gel and eye drops and additionally received oral ACV 400 mg 5 times a day for 10 weeks and followed by 400 mg 2 times per day for 6 months; test GCV group was topically adopted the same treatment as negative control group and additionally received oral GCV 1000 mg 3 times per day for 8 weeks. The symptoms and signs were evaluated before and after the therapy 1 st week, 2 nd week and then followed up every 2 weeks until recovery. Furthermore, we followed up recurrence of HSK for every 3 months after recovery and then assessed the cure time, recurrent rate and adverse reactions. RESULTS: One hundred and seventy-three patients were followed up 7-48 months (mean 32.1 ± 12.3 months), but 34 patients were failed to follow-up. The cure time was 12.1 ± 4.3, 11.9 ± 4.0 weeks in negative control (placebo) group and positive control ACV group respectively (P = 0.991), which was longer than that in test GCV group (8.6 ± 2.8 weeks) and there was a significant difference between test GCV group and negative control (placebo) group or positive control ACV group (P = 0.000). Furthermore, the recurrent rate was higher in negative control (placebo) group (47.3%) than that in positive control group ACV (26.7%) and test GCV group (17.2%), and there was a great significant difference among the three groups (P = 0.007), but there was no significant difference between positive control ACV group and test GCV group (P = 0.358). In addition, there was no obvious adverse reaction expect neutropenia (only one patient in test GCV group). CONCLUSION: Short-term oral GCV could cure recurrent HSK and endotheliitis, shorten the course, reduce recurrent rate of HSK and have confirmed safety.