Magnetic phase transitions in the triangular-lattice spin-1 dimer compound K2Ni2(SeO3)3

In our study, we conduct magnetization and heat capacity measurements to investigate field-induced magnetic phase transitions within the newly synthesized compound K2Ni2(SeO3)3, a spin-1 dimer system arranged on a triangular lattice. The Ni-Ni dimers exhibit a ferromagnetic intra-dimer interaction, effectively behaving as an ensemble with a total spin of S=2. In contrast, antiferromagnetic interactions manifest between these dimers on the triangular lattice. The trigonal distortion of the NiO6 octahedra introduces easy-axis magnetic anisotropy, accounting for the distinct magnetic phase diagrams observed when applying c-axis directional and in-plnae magnetic fields. Notably, our investigation unveils a two-step phase transition with the magnetic field aligned with the c direction. We propose that the system at the first transition is from a paramagnetic state to an up-up-down state, characterized by the Z3 lattice-symmetry breaking. Subsequently, a Berezinskii-Kosterlitz-Thouless transition, involving the breaking of the c-axis spin-rotation symmetry, leads to the formation of the "Y state" at low temperatures. These findings yield valuable insights into the magnetic phase transitions inherent to geometrically frustrated magnetic systems featuring dimer structures.Comment: 10 pages, 11 figure

Review and prospect of coal rock hydraulic fracturing physical experimental research

Physical simulation of hydraulic fracturing is an approximate representation of fracture evolution and its dynamic process, which represents an important direction of fracture evolution research. Similarity theory is the theoretical basis of the transformation between field prototype and experimental model. Test equipment and similar materials are the material premise of physical simulation experiment. Monitoring and detection technology is the key part to evaluate the fracturing effect of hydraulic fracturing. This paper summarizes the development of similarity theory of hydraulic fracturing physical experiments, the evolution of experimental materials and devices, and the characteristics and application scope of common monitoring and detection methods from the above three aspects. The analysis shows that: the similarity criterion of hydraulic fracturing has been preliminarily formed, but it needs to be further modified according to the physical and mechanical properties of coal and rock. Numerical simulation method can be used to explore the influence degree of minor factors ignored in the derivation of similarity criterion, so as to improve the reliability and applicability of the empirical equation. In view of various physical and mechanical properties of coal and rock, many empirical formula equations of similar materials have been obtained at present, but a set of detailed experimental specification and a large number of experimental attempts are still needed to improve the repeatability of the experiments, so as to establish a more universal database of empirical equations of similar material matching. Fracturing devices are developing towards the direction of multi-field coupling with more simulation conditions, larger simulation scale and wider simulation range, and fracturing methods are gradually diversified with engineering applications. However, the accuracy of triaxial loading of fracturing devices needs to be further improved to ensure effective fracturing experiments under high stress conditions, and reduce the impact of experimental operations on the final results. Monitoring methods and detection technologies have their own advantages in evaluating the fracturing effect of hydraulic fracturing, and similar materials also have a significant impact on the effectiveness and accuracy of monitoring methods and detection technologies. How to rationally select and combine monitoring methods and detection technologies based on experiments is the key to meet the research needs of micro-structures

Actin filament reorganisation controlled by the SCAR/WAVE complex mediates stomatal response to darkness.

This is the final version of the article. Available from the publisher via the DOI in this record.Stomata respond to darkness by closing to prevent excessive water loss during the night. Although the reorganisation of actin filaments during stomatal closure is documented, the underlying mechanisms responsible for dark-induced cytoskeletal arrangement remain largely unknown. We used genetic, physiological and cell biological approaches to show that reorganisation of the actin cytoskeleton is required for dark-induced stomatal closure. The opal5 mutant does not close in response to darkness but exhibits wild-type (WT) behaviour when exposed to abscisic acid (ABA) or CaCl2 . The mutation was mapped to At5g18410, encoding the PIR/SRA1/KLK subunit of the ArabidopsisSCAR/WAVE complex. Stomata of an independent allele of the PIR gene (Atpir-1) showed reduced sensitivity to darkness and F1 progenies of the cross between opal5 and Atpir-1 displayed distorted leaf trichomes, suggesting that the two mutants are allelic. Darkness induced changes in the extent of actin filament bundling in WT. These were abolished in opal5. Disruption of filamentous actin using latrunculin B or cytochalasin D restored wild-type stomatal sensitivity to darkness in opal5. Our findings suggest that the stomatal response to darkness is mediated by reorganisation of guard cell actin filaments, a process that is finely tuned by the conserved SCAR/WAVE-Arp2/3 actin regulatory module.This work was supported by grants from the BBSRC (BB/ N001168/1; BB/J002364/1; BBF001177/1), The Gatsby Charitable Foundation and the Leverhulme Trust to A.M.H. and grants from the National Natural Science Foundation of China (nos. 31300213 and 31670408 to K.J.). This work was also supported by the Centre National de la Recherche Scientifique and the Commissariat a l’Energie Atomique et aux Energies Alternatives (for the IR camera) and the European Union Marie Curie FP5 Research Training Network (program no. STRESSIMAGING HNRT-CT-2002-00254 to J.M.C. and B.G.). J.M.C. was in addition supported by a scholarship of the Fundac ~ao para a Ci^encia e Tecnologia, Portugal (grant no. SFRH/BPD/34429/2006)

Birth cohorts in asthma and allergic diseases: Report of a NIAID/NHLBI/MeDALL joint workshop

Population-based birth cohorts on asthma and allergies increasingly provide new insights into the development and natural history of the diseases. Over 130 birth cohorts focusing on asthma and allergy have been initiated in the last 30 years. A NIAID (National Institute of Allergy and Infectious Diseases), NHLBI (National Heart Lung and Blood Institute), MeDALL (Mechanisms of the Development of Allergy, Framework Programme 7 of the European Commission) joint workshop was held in Bethesda, MD, USA September 11–12, 2012 with 3 objectives (1) documenting the knowledge that asthma/allergy birth cohorts have provided, (2) identifying the knowledge gaps and inconsistencies and (3) developing strategies for moving forward, including potential new study designs and the harmonization of existing asthma birth cohort data. The meeting was organized around the presentations of 5 distinct workgroups: (1) clinical phenotypes, (2) risk factors, (3) immune development of asthma and allergy, (4) pulmonary development and (5) harmonization of existing birth cohorts. This manuscript presents the workgroup reports and provides web links (AsthmaBirthCohorts.niaid.nih.gov or www.medall-fp7.eu) where the reader will find tables describing the characteristics of the birth cohorts included in this report, type of data collected at differing ages, and a selected bibliography provided by the participating birth cohorts

Ambient Excitation for Detection of Damage in Timber Bridges

As the needs for transportation systems change, the loading requirements and demands on the transportation infrastructure also change. This has resulted in increased number of bridges that are labeled structurally deficient or functionally obsolete since many of the bridges were built prior to present loading requirements [1]. Many of these bridges are open to vehicular and railroad traffic but only at posted loading limits or at reduced speed limits. In order to best use the existing bridge resource and/or schedule repair or replacement strategies, methods need to be developed to assess the actual condition of these transportation structures.</p