Stabilizing low symmetry-based functions of materials at room temperature through isosymmetric electronic bistability.

Symmetry-breaking is pivotal for controlling ferroelectric, ferroelastic and/or ferromagnetic functions of materials, which enables applications in sensors, memory devices, transducers or actuators. Commonly, ferroic phases emerge from descending symmetry-breaking, as the laws of thermodynamics dictate that the ordered low entropy phases form at low temperature, which limits practical applications of many materials at room temperature. Rare examples of ascending symmetry-breakings have been observed, but the driving force remains often unclear.

Strain-affected ferroelastic domain walls in RbMnFe charge-transfer materials undergoing collective Jahn-Teller distortion.

Many rubidium manganese hexacyanoferrate materials, with the general formula Rb Mn[Fe(CN)]·HO, exhibit diverse charge-transfer-based functionalities due to the bistability between a high temperature Mn( = 5/2)Fe( = 1/2) cubic phase and a low-temperature Mn( = 2)Fe( = 0) tetragonal phase. The collective Jahn-Teller distortion on the Mn sites is responsible for the cubic-to-tetragonal ferroelastic phase transition, which is associated with the appearance of ferroelastic domains. In this study, we use X-ray diffraction to reveal the coexistence of 3 types of ferroelastic tetragonal domains and estimate the spatial extension of the strain around the domain walls, which represents about 30% of the volume of the crystal.

From Ultrafast Photoinduced Small Polarons to Cooperative and Macroscopic Charge-Transfer Phase Transition.

We study by femtosecond infrared spectroscopy the ultrafast and persistent photoinduced phase transition of the RbMnCo[Fe(CN)] ⋅ 0.2HO material, induced at room temperature by a single laser shot. This system exhibits a charge-transfer based phase transition with a 75 K wide thermal hysteresis, centred at room temperature, from the low temperature Mn-N-C-Fe tetragonal phase to the high temperature Mn-N-C-Fe cubic phase.

Observation of a Picosecond Light-Induced Spin Transition in Polymeric Nanorods.

Spin transition (ST) materials are attractive for developing photoswitchable devices, but their slow material transformations limit device applications. Size reduction could enable faster switching, but the photoinduced dynamics at the nanoscale remains poorly understood. Here, we report a femtosecond optical pump multimodal X-ray probe study of polymeric nanorods.

Magnetoelectric and MIESST effects in spin crossover materials exhibiting symmetry-breaking.

Giant magnetoelectric coupling and magnetic-field-induced spin state trapping (MIESST) were recently reported in spin crossover materials with polar phases. We discuss these phenomena considering the distinct contributions of the change of the molecular spin state, driven by the magnetic field, and the coupled structural symmetry-breaking during the stepwise change of electric polarisation or MIESST.

A common polymorphism in the Intelectin-1 gene influences mucus plugging in severe asthma.

By incompletely understood mechanisms, type 2 (T2) inflammation present in the airways of severe asthmatics drives the formation of pathologic mucus which leads to airway mucus plugging. Here we investigate the molecular role and clinical significance of intelectin-1 (ITLN-1) in the development of pathologic airway mucus in asthma. Through analyses of human airway epithelial cells we find that ITLN1 gene expression is highly induced by interleukin-13 (IL-13) in a subset of metaplastic MUC5AC mucus secretory cells, and that ITLN-1 protein is a secreted component of IL-13-induced mucus.

Ultrafast and persistent photoinduced phase transition at room temperature monitored by streaming powder diffraction.

Ultrafast photoinduced phase transitions at room temperature, driven by a single laser shot and persisting long after stimuli, represent emerging routes for ultrafast control over materials' properties. Time-resolved studies provide fundamental mechanistic insight into far-from-equilibrium electronic and structural dynamics. Here we study the photoinduced phase transformation of the RbMnCo[Fe(CN)] material, designed to exhibit a 75 K wide thermal hysteresis around room temperature between MnFe tetragonal and MnFe cubic phases.

Bidirectional photoswitchability in an iron(iii) spin crossover complex: symmetry-breaking and solvent effects.

The impact of solvent on spin crossover (SCO) behaviour is reported in two solvates [Fe(qsal-I)]NO·2ROH (qsal-I = 4-iodo-2-[(8-quinolylimino)methyl]phenolate; R = Me 1 or Et 2) which undergo abrupt and gradual SCO, respectively. A symmetry-breaking phase transition due to spin-state ordering from a [HS] to [HS-LS] state occurs at 210 K in 1, while = 250 K for the EtOH solvate, where complete SCO occurs. The MeOH solvate exhibits LIESST and -LIESST from the [HS-LS] state, revealing a hidden [LS] state.

Hand eczema in glove-wearing patients.

Background: Allergic contact dermatitis to gloves is mostly induced by rubber accelerators. The European baseline series (EBS) appears insufficient to detect glove allergy. Since 2017, it is recommended to use the European rubber series (ERS) and to test the patients' own gloves.

The mutant implicates endosome trafficking in ciliate, cortical pattern formation.

Ciliates, such as evolved complex mechanisms to determine both the location and dimensions of cortical organelles such as the oral apparatus (OA: involved in phagocytosis), cytoproct (Cyp: for eliminating wastes), and contractile vacuole pores (CVPs: involved in water expulsion). Mutations have been recovered in that affect both the localization of such organelles along anterior-posterior and circumferential body axes and their dimensions. Here we describe , a ciliate pattern gene that encodes a conserved Beige-BEACH domain-containing protein a with possible protein kinase A (PKA)-anchoring activity.

Timing and frequency of high temperature events bend the onset of behavioural thermoregulation in Atlantic salmon ().

The role of temperature on biological activities and the correspondent exponential relationship with temperature has been known for over a century. However, lacking to date is knowledge relating to (a) the recovery of ectotherms subjected to extreme temperatures in the wild, and (b) the effects repeated extreme temperatures have on the temperatures that induce behavioural thermoregulation (aggregations). We examined these questions by testing the hypothesis that thermal thresholds which initiate aggregations in juvenile Atlantic salmon (AS) () are not static, but are temporally dynamic across a summer and follow a hysteresis loop.

Metal-to-metal electron transfer in a cyanido-bridged {FeCo} square complex followed by X-ray diffraction and absorption techniques.

The switching properties of a cyanido-bridged Fe/Co square molecule were investigated by single-crystal X-ray diffraction and X-ray absorption spectroscopy at both Fe and Co K-edges. Combining these two techniques, a complete picture of the thermal-, light- and X-ray-induced metal-to-metal electron transfer is obtained, illustrating the concerted role played by the Fe and Co sites.

Out-of-equilibrium dynamics driven by photoinduced charge transfer in CsCoFe Prussian blue analogue nanocrystals.

In this paper we study the out-of-equilibrium dynamics associated with photoinduced charge-transfer (CT) in cyanide-bridged Co-Fe Prussian blue analogue nanocrystals. In these coordination networks, the structural trapping of the photoinduced CT polaron involves local electronic and structural reorganizations. Femtosecond X-ray and optical absorption spectroscopies show that the local structural trapping process occurs on similar timescale for particles with 11 nm and 70 nm sizes.

Impact of the terahertz and optical pump penetration depths on generated strain waves temporal profiles in a VO thin film.

Triggering new stable macroscopic orders in materials by ultrafast optical or terahertz pump pulses is a difficult challenge, complicated by the interplay between multiscale microscopic mechanisms, and macroscopic excitation profiles in samples. In particular, the differences between the two types of excitations are still unclear. In this article, we compare the optical response on acoustic timescale of a VO Paramagnetic Metallic (PM) thin film excited by a terahertz (THz) pump or an optical pump, at room temperature.

Domain Wall Dynamics in a Ferroelastic Spin Crossover Complex with Giant Magnetoelectric Coupling.

Pinned and mobile ferroelastic domain walls are detected in response to mechanical stress in a Mn complex with two-step thermal switching between the spin triplet and spin quintet forms. Single-crystal X-ray diffraction and resonant ultrasound spectroscopy on [Mn(3,5-diCl-sal(323))]BPh reveal three distinct symmetry-breaking phase transitions in the polar space group series → → 1 → 1 The transition mechanisms involve coupling between structural and spin state order parameters, and the three transitions are Landau tricritical, first order, and first order, respectively. The two first-order phase transitions also show changes in magnetic properties and spin state ordering in the Jahn-Teller-active Mn complex.

Thermal and Magnetic Field Switching in a Two-Step Hysteretic Mn Spin Crossover Compound Coupled to Symmetry Breakings.

A Mn spin crossover complex with atypical two-step hysteretic thermal switching at 74 K and 84 K shows rich structural-magnetic interplay and magnetic-field-induced spin state switching below 14 T with an onset below 5 T. The spin states, structures, and the nature of the phase transitions are elucidated via X-ray and magnetization measurements. An unusual intermediate phase containing four individual sites, where are in a pure low spin state, is observed.