A ten-fold coordinated high-pressure structure in hafnium dihydrogen with increasing superconducting transition temperature induced by enhancive pressure

High pressure is an effective method to induce structural and electronic changes,creating novel high-pressure structures with excellent physical and chemical properties.Herein,we investigate the structural phase transition of hafnium dihydrogen(HfH2)in a pressure range of 0 GPa-500 GPa through the first-principles calculations and the crystal structure analysis by particle swarm optimization(CALYPSO)code.The high-pressure phase transition sequence of HfH2is I4/mmm→Cmma→P-3m1 and the two phase transition pressure points are 220.21 GPa and 359.18 GPa,respectively.A newly trigonal P-3m1 structure with 10-fold coordination first appears as an energy superior structure under high pressure.These three structures are all metallic with the internal ionic bonding of Hf and H atoms.Moreover,the superconducting transition temperature(Tc)values of Cmma at 300 GPa and P-3m1 at 500 GPa are 3.439 K and 19.737 K,respectively.Interestingly,the superconducting transition temperature of the P-3m1 structure presents an upward trend with the pressure rising,which can be attributed to the increase of electron-phonon coupling caused by the enhanced Hf-d electronic density of states at Fermi level under high pressure.

Pressure-induced novel structure with graphene-like boron-layer in titanium monoboride

The recent discovery of the novel boron-framework in boron-rich metal borides with complex structures and intriguing features under high pressure has stimulated the search into the unique boron-network in the metal monoborides or boron-deficient metal borides at high pressure.Herein,based on the particle swarm optimization algorithm combined with first-principles calculations,we thoroughly explored the structural evolution and properties of TiB up to 200 GPa.This material undergoes a pressure-induced phase transition of Pnma→Cmcm→Pmmm.Besides of two known phases Pnma and Cmcm,an unexpected orthorhombic Pmmm structure was predicted to be energetically favored in the pressure range of 110.88–200 GPa.Intriguingly,the B covalent network eventually evolved from a one-dimensional zigzag chain in Pnma-TiB and Cmcm-TiB to a graphene-like B-sheet in Pmmm-TiB.On the basis of the microscopic hardness model,the calculated hardness(H_(v))values of Pnma at 1 atm,Cmcm at 100 GPa,and Pmmm at 140 GPa are 36.81 GPa,25.17 GPa,and15.36 GPa,respectively.Remarkably,analyses of the density of states,electron localization function and the crystal orbital Hamilton population(COHP)exhibit that the bonding nature in the three TiB structures can be considered as a combination of the B–B and Ti–B covalent interactions.Moreover,the high hardness and excellent mechanical properties of the three Ti B polymorphs can be ascribed to the strong B–B and Ti–B covalent bonds.

Systematic review/meta-analysis re-evaluation of clinical effects of total glucosides of paeony in the treatment of rheumatoid arthritis

Objective: To re-evaluate the systematic review of Rheumatoid arthritis (RA) treatmentwith total glucosides of paeony (TGP) to provide evidence-based evidence for the treatmentof RA with TGP in the clinic. Methods: A total of eight databases including CNKI, Wan FangData, CBM, VIP, PubMed, Embase, Cochrane Library, and Web of Science were searched bycomputer for the systematic reviews/meta-analyses concerning the treatment of RA withTGP. The retrieval period was from the establishment of the database to May 2, 2022.Literature screening was conducted based on the randomized controlled trial, and thematerials of the included literature were extracted. Using the preferred reporting items forsystematic reviews and meta-analyses statement. The a measurement tool to assesssystematic reviews 2 scale and grades of recommendation, assessment, development, andevaluation system evaluated the reporting quality, methodological quality, and outcomeindicators evidence levels included in the literature. Results: Six systematicreviews/meta-analysis literature were finally included. Evaluation of the preferred reportingitems for systematic reviews and meta-analyses statement showed that the overall reportingquality of included literature was low, and only one piece with high quality was included.The results of the a measurement tool to assess systematic reviews 2 scale evaluationshowed that the qualities of included literature were all low-level and highly low-level. Thegrades of recommendation, assessment, development, and evaluation evidence qualityevaluation showed a total of 39 outcome indicators in the six included literature, and alloutcome indicators were intermediate, low-level, and extremely low in evidence evaluation.Conclusion: Many pieces of evidence show that TGP has certain advantages in alleviatingclinical symptoms, reducing adverse reactions, and reducing hepatotoxicity in the treatmentof RA, but this conclusion lacks high-level evidence to support it, which needs to be provedby more studies in the future.