Search

Spin-crossover (SCO) ferroelectrics with dual-function switches have attracted great attention for significant magnetoelectric application prospects. However, the multiferroic crystals with SCO features have rarely been reported. Herein, a molecular multiferroic Fe(II) crystalline complex [Fe II (C 8 -F-pbh) 2 ] (1-F, C 8 -F-pbh = (1Z,N'E)-3-F-4-(octyloxy)-N'-(pyridin-2-ylmethylene)-benzo-hydrazonate) showing the coexistence of ferroelectricity, ferroelasticity, and SCO behavior is presented for the first time. By H/F substitution, the low phase transition temperature (270 K) of the non-fluorinated parent compound is significantly increased to 318 K in 1-F, which exhibits a spatial symmetry breaking 222F2 type ferroelectric phase transition with clear room-temperature ferroelectricity. Besides, 1-F also displays a spin transition between high- and low-spin states, accompanied by the d-orbital breaking within the t 2g 4 e g 2 and t 2g 6 e g ° configuration change of octahedrally coordinated Fe II center. Moreover, the 222F2 type ferroelectric phase transition is also a ferroelastic one, verified by the ferroelectric domains reversal and the evolution of ferroelastic domains. To the knowledge, 1-F is the first multiferroic SCO molecular crystal. This unprecedented finding sheds light on the exploration of molecular multistability materials for future smart devices., (© 2024 Wiley‐VCH GmbH.)

Ferroelectrics as emerging and attractive catalysts have shown tremendous potential for applications including wastewater treatment, hydrogen production, nitrogen fixation, and organic synthesis, etc. In this study, we demonstrate that molecular ferroelectric crystal TMCM-CdCl 3 (TMCM = trimethylchloromethylammonium) with multiaxial ferroelectricity and superior piezoelectricity has an effective catalytic activity on the direct construction of the pharmacologically important substituted quinoline derivatives via one-pot [3 + 2 + 1] annulation of anilines and terminal alkynes by using N,N-dimethylformamide (DMF) as the carbon source. The recrystallized TMCM-CdCl 3 crystals from DMF remain well ferroelectricity and piezoelectricity. Upon ultrasonic condition, periodic changes in polarization contribute to the release of free charges from the surface of the ferroelectric domains in nano size, which then quickly interacts with the substrates in the solution to trigger the pivotal redox process. Our work advances the molecular ferroelectric crystal as a catalytic route to organic synthesis, not only providing valuable direction for molecular ferroelectrics but also further enriching the executable range of ferroelectric catalysis., (© 2024. The Author(s).)

Background: Diabetic foot ulcers (DFU), as severe complications of diabetes mellitus (DM), significantly compromise patient health and carry risks of amputation and mortality., Aim: To offer new insights into the occurrence and development of DFU, focusing on the therapeutic mechanisms of X-Paste (XP) of wound healing in diabetic mice., Methods: Employing traditional Chinese medicine ointment preparation methods, XP combines various medicinal ingredients. High-performance liquid chromatography (HPLC) identified XP's main components. Using streptozotocin (STZ)-induced diabetic, we aimed to investigate whether XP participated in the process of diabetic wound healing. RNA-sequencing analyzed gene expression differences between XP-treated and control groups. Molecular docking clarified XP's treatment mechanisms for diabetic wound healing. Human umbilical vein endothelial cells (HUVECs) were used to investigate the effects of Andrographolide (Andro) on cell viability, reactive oxygen species generation, apoptosis, proliferation, and metastasis in vitro following exposure to high glucose (HG), while NF-E2-related factor-2 ( Nrf2 ) knockdown elucidated Andro's molecular mechanisms., Results: XP notably enhanced wound healing in mice, expediting the healing process. RNA-sequencing revealed Nrf2 upregulation in DM tissues following XP treatment. HPLC identified 21 primary XP components, with Andro exhibiting strong Nrf2 binding. Andro mitigated HG-induced HUVECs proliferation, metastasis, angiogenic injury, and inflammation inhibition. Andro alleviates HG-induced HUVECs damage through Nrf2 /HO-1 pathway activation, with Nrf2 knockdown reducing Andro's proliferative and endothelial protective effects., Conclusion: XP significantly promotes wound healing in STZ-induced diabetic models. As XP's key component, Andro activates the Nrf2 /HO-1 signaling pathway, enhancing cell proliferation, tubule formation, and inflammation reduction., Competing Interests: Conflict-of-interest statement: The authors have declared that no competing interest exists., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)

Clarifying current situation of farmers' fertilization and yield in citrus producing areas and the effects of different fertilization measures can provide a scientific basis for improving the yield and quality of citrus in China. We retrieved 92 literatures on citrus fertilization from the CNKI and Web of Science to examine the impacts of nitrogen (N), phosphorus (P or P 2 O 5 ), and potassium (K or K 2 O) fertilizer dosage and partial productivity under farmers' conventional fertilization and experts' optimized fertilization, as well as the effects of optimized fertilization measures on citrus yield and quality by using meta-analysis approach. The average conventional application rates of N, P 2 O 5 , and K 2 O were 507.3, 262.2, and 369.3 kg·hm -2 in citrus production in China. Compared with conventional fertilization, optimized fertilization resulted in a reduction of N and P 2 O 5 by 14.7% and 8.3%, an increase in K 2 O application by 6.6%, which promoted partial productivity of N, P 2 O 5 , and K 2 O fertilizers by 7.8%, 18.4%, and 14.7%, correspondingly. The optimized fertilization resulted in 11.9% and 2.8% increase in fruit yield and single fruit weight, while improved vitamin C content (Vc, 3.1%), total soluble solids (TSS, 5.9%) and total sugar content (TSC, 8.6%). Additionally, it also led to a reduction in titratable acid (TA, -3.4%) and total acid content (TAC, -3.6%), and consequently elevated the TSS/TA (14.0%) and TSC/TAC (9.5%). Among different optimized fertilization methods, the effect of optimized NPK + medium and/or micro element fertilizer on citrus yield and fruit quality was the best, especially NPK decrement ≤25% between optimized NPK measures. The effect of conventional NPK + organic fertilizer was higher than conventional NPK + medium and/or micro element fertilizer. However, different citrus varieties, including mandarins, pomelos, and oranges, showed different responses to optimized fertilization. Optimized fertilization management could synergistically improve citrus yield, fertilizer use efficiency, and fruit quality. Therefore, the strategy of integrated nutrient management1 with reducing NPK fertilizer, balancing medium and/or micro nutrient fertilizer and improving soil fertility by organic fertilizer should be adopted according to local conditions in citrus producing areas of China.

Here, we synthesized a series of cholesteryl-based compounds, whose phases and their transformation can be modulated by temperature and the chain length of the fluoroalkyl moieties. To our knowledge, this is the first time that the phase transition could be modulated with perfluoroalkyl tail engineering in organic single-component ferroelectric crystals.

Thermally triggered spatial symmetry breaking in traditional ferroelectrics has been extensively studied for manipulation of the ferroelectricity. However, photoinduced molecular orbital breaking, which is promising for optical control of ferroelectric polarization, has been rarely explored. Herein, for the first time, we synthesized a homochiral fulgide organic ferroelectric crystal (E)-(R)-3-methyl-3-cyclohexylidene-4-(diphenylmethylene)dihydro-2,5-furandione (1), which exhibits both ferroelectricity and photoisomerization. Significantly, 1 shows a photoinduced reversible change in its molecular orbitals from the 3 π molecular orbitals in the open-ring isomer to 2 π and 1 σ molecular orbitals in the closed-ring isomer, which enables reversible ferroelectric domain switching by optical manipulation. To our knowledge, this is the first report revealing the manipulation of ferroelectric polarization in homochiral ferroelectric crystal by photoinduced breaking of molecular orbitals. This finding sheds light on the exploration of molecular orbital breaking in ferroelectrics for optical manipulation of ferroelectricity., (© 2023 Wiley-VCH GmbH.)

As particles carry quantified energy, photon radiation enables orbital transitions of energy levels, leading to changes in the spin state of electrons. The resulting switchable structural bistability may bring a new paradigm for manipulating ferroelectric polarization. However, the studies on molecular orbital breaking in the ferroelectric field remain blank. Here, for the first time, a new mechanism of ferroelectrics-dual breaking of molecular orbitals and spatial symmetry, demonstrated in a photochromic organic crystal with light-induced polarization switching, is formally proposed. By alternating the ultraviolet/visible light irradiation, the states of electron spin and the radial distribution p atomic orbitals experience a change, showing a reversible switch from "shoulder-to-shoulder" form to a "head-to-head" form. This reflects a reversible conversion between π and σ bonds, which induces and couples with the variation of spatial symmetry. The intersection of spatial symmetry breaking and molecular orbital breaking in ferroelectrics present in this work will be more conducive to data encryption and anticounterfeiting., (© 2023 Wiley-VCH GmbH.)

Fullerenes offer versatile functionalities and are promising materials for a widespread range of applications from biomedicine and energy to electronics. Great efforts have been made to manipulate the symmetries of fullerene and its derivatives for studying material properties and novel effects, such as ferroelectricity with polar symmetry; however, no documentary report has been obtained to realize their ferroelectricity. Here, for the first time, we demonstrated clear ferroelectricity in a fullerene adduct formed by C 60 and S 8 . More is different: the combination of the most symmetric molecule C 60 with the highest I h symmetry and molecule S 8 with high D 4 d symmetry resulted in the polar C 60 S 8 adduct with a low crystallographic symmetry of the C 2 v ( mm 2) point group at room temperature. The presented C 60 S 8 undergoes polar-to-polar ferroelectric phase transition with the mm 2F m notation, whose ferroelectricity was confirmed by a ferroelectric hysteresis loop and ferroelectric domain switching. This finding opens up a new functionality for fullerenes and sheds light on the exploration of more ferroelectric fullerenes.

Background: Diabetic skin ulcers, a significant global healthcare burden, are mainly caused by the inhibition of cell proliferation and impaired angiogenesis. XB130 is an adaptor protein that regulates cell proliferation and migration. However, the role of XB130 in the development of diabetic skin ulcers remains unclear., Aim: To investigate whether XB130 can regulate the inhibition of proliferation and vascular damage induced by high glucose. Additionally, we aim to determine whether XB130 is involved in the healing process of diabetic skin ulcers, along with its molecular mechanisms., Methods: We conducted RNA-sequencing analysis to identify the key genes involved in diabetic skin ulcers. We investigated the effects of XB130 on wound healing using histological analyses. In addition, we used reverse transcription-quantitative polymerase chain reaction, Western blot, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining, immunofluorescence, wound healing, and tubule formation experiments to investigate their effects on cellular processes in human umbilical vein endothelial cells (HUVECs) stimulated with high glucose. Finally, we performed functional analysis to elucidate the molecular mechanisms underlying diabetic skin ulcers., Results: RNA-sequencing analysis showed that the expression of XB130 was up-regulated in the tissues of diabetic skin ulcers. Knockdown of XB130 promoted the healing of skin wounds in mice, leading to an accelerated wound healing process and shortened wound healing time. At the cellular level, knockdown of XB130 alleviated high glucose-induced inhibition of cell proliferation and angiogenic impairment in HUVECs. Inhibition of the PI3K/Akt pathway removed the proliferative effects and endothelial protection mediated by XB130., Conclusion: The findings of this study indicated that the expression of XB130 is up-regulated in high glucose-stimulated diabetic skin ulcers and HUVECs. Knockdown of XB130 promotes cell proliferation and angiogenesis via the PI3K/Akt signalling pathway, which accelerates the healing of diabetic skin ulcers., Competing Interests: Conflict-of-interest statement: All the authors have declared no conflict of interest., (©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.)

Bismuth(III) iodide perovskites have attracted great attention as lead-free hybrid semiconductors, but they mainly show zero- and one-dimensional structures. Herein, we report the first two-dimensional chiral perovskite-like bismuth(III) iodide hybrid [( S )-3-aminopyrrolidinium I] 2 Bi 2/3 I 4 ( 1 ) with a high phase transition temperature of 408.8 K, higher than most of the reported chiral lead-free hybrid semiconductors.

Chiral ferroelectric crystals with intriguing features have attracted great interest and many with point or axial chirality based on the stereocarbon have been successively developed in recent years. However, ferroelectric crystals with stereogenic heteroatomic chirality have never been documented so far. Here, we discover and report a pair of enantiomeric stereogenic sulfur-chiral single-component organic ferroelectric crystals, R s -tert-butanesulfinamide (R s -tBuSA) and S s -tert-butanesulfinamide (S s -tBuSA) through the deep understanding of the chemical design of molecular ferroelectric crystals. Both enantiomers adopt chiral-polar point group 2 (C 2 ) and exhibit mirror-image relationships. They undergo high-temperature 432F2-type plastic ferroelectric phase transition around 348 K. The ferroelectricity has been well confirmed by ferroelectric hysteresis loops and domains. Polarized light microscopy records the evolution of the ferroelastic domains, according with the fact that the 432F2-type phase transition is both ferroelectric and ferroelastic. The very soft characteristics with low elastic modulus and hardness reveals their excellent mechanical flexibility. This finding indicates the first stereosulfur chiral molecular ferroelectric crystals, opening up new fertile ground for exploring molecular ferroelectric crystals with great application prospects., (© 2023 Wiley-VCH GmbH.)

Ferroelectricity has been separately found in numerous solid and liquid crystal materials since its first discovery in 1920. However, a single material with biferroelectricity existing in both solid and liquid crystal phases is very rare, and the regulation of biferroelectricity has never been studied. Here, solid-liquid crystal biphasic ferroelectrics, cholestanyl 4-X-benzoate (4X-CB, X = Cl, Br, and I), which exhibits biferroelectricity in both the solid and liquid crystal phases, is presented. It is noted that the ferroelectric liquid crystal phase of 4X-CB is a cholesteric one, distinct from the ordinary chiral smectic ferroelectric liquid crystal phase. Moreover, 4X-CB shows solid-solid and solid-liquid crystal phase transitions, of which the transition temperatures gradually increase from Cl to Br to I substitution. The spontaneous polarization (P s ) of 4X-CB in both solid and liquid crystal phases can also be regulated by different halogen substitutions, where the 4Br-CB has the optimal P s because of the larger molecular dipole moment. To the authors' knowledge, 4X-CB is the first ferroelectric with tunable biferroelectricity, which offers a feasible case for the performance optimization of solid-liquid crystal biphasic ferroelectrics., (© 2023 Wiley-VCH GmbH.)

Inorganic ferroelectrics have long dominated research and applications, taking advantage of high piezoelectric performance in bulk polycrystalline ceramic forms. Molecular ferroelectrics have attracted growing interest because of their environmental friendliness, easy processing, lightweight, and good biocompatibility, while realizing the considerable piezoelectricity in their bulk polycrystalline forms remains a great challenge. Herein, for the first time, through ring enlargement, a molecular ferroelectric 1-azabicyclo[3.2.1]octonium perrhenate ([3.2.1-abco]ReO 4 ) with a large piezoelectric coefficient d 33 up to 118 pC/N in the polycrystalline pellet form is designed, which is higher than that of the parent 1-azabicyclo[2.2.1]heptanium perrhenate ([2.2.1-abch]ReO 4 , 90 pC/N) and those of most molecular ferroelectrics in polycrystalline or even single crystal forms. The ring enlargement reduces the molecular strain for easier molecular deformation, which contributes to the higher piezoelectric response in [3.2.1-abco]ReO 4 . This work opens up a new avenue for exploring high piezoelectric polycrystalline molecular ferroelectrics with great potential in piezoelectric applications., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Objective: Thirty-day readmission is one of the common complications after lumbar surgery. More 30-day readmission increases the total hospitalization, economic burden, and physical pain of patients, delays the progress of postoperative rehabilitation, and even lead to die. Therefore, it is necessary to analyze the risk factors of 30-day readmission following lumbar surgery., Methods: We searched for all the clinical trials published from the establishment of the database to May 1, 2022 through the Cochrane Library, Web of Science, Embase, and PubMed. Data including age, American Society of Anesthesiology physical status class, preoperative hematocrit (Hct), diabetes mellitus (DM), current smoker, chronic obstructive pulmonary disease (COPD), length of hospital stay (LHS), operation time, and surgical site infection (SSI) were extracted. We used Review Manager 5.4 for data analysis., Results: Six studies with 30,989 participants were eligible for this meta-analysis. The analysis revealed that there were statistically significant differences in the age (95% confidence interval [CI]: -3.35-2.90, P < 0.001), preoperative Hct (95% CI: 0.75-1.33, P < 0.001), DM (95% CI: 0.56-0.74, P < 0.001), COPD (95% CI: 0.38-0.58, P < 0.001), operation time (95% CI: -35.54-16.18, P < 0.001), LHS (95% CI: -0.54-0.50, P < 0.001), and SSI (95% CI: 0.02-0.03, P < 0.001) between no readmission and readmission groups. In terms of the American Society of Anesthesiology physical status class and current smoker, there was no significant effect on the 30-day readmission (P = 0.16 and P = 0.35 respectively)., Conclusions: Age, preoperative Hct, DM, COPD, operation time, LHS, and SSI are the danger factors of 30-day readmission following lumbar surgery., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Ferroelectric materials are a special type of polar substances, including solids or liquid crystals. However, obtaining a material to be ferroelectric in both its solid crystal (SC) and liquid crystal (LC) phases is a great challenge. Moreover, although cholesteric LCs inherently possess the advantage of high fluidity, their ferroelectricity remains unknown. Here, through the reasonable H/F substitution on the fourth position of the phenyl group of the parent nonferroelectric dihydrocholesteryl benzoate, we designed ferroelectric dihydrocholesteryl 4-fluorobenzoate (4-F-BDC), which shows ferroelectricity in both SC and cholesteric LC phases. The fluorination induces a lower symmetric polar P 1 space group and a new solid-to-solid phase transition in 4-F-BDC. Beneficial from fluorination, the SC and cholesteric LC phases of 4-F-BDC show clear ferroelectricity, as confirmed by well-shaped polarization-voltage hysteresis loops. The dual ferroelectricity in both SC and cholesteric LC phases of a single material was rarely found. This work offers a viable case for the exploration of the interplay between ferroelectric SC and LC phases and provides an efficient approach for designing ferroelectrics with dual ferroelectricity and cholesteric ferroelectric liquid crystals., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Metal-free perovskites with light weight and eco-friendly processability have received great interest in recent years due to their superior physical features in ferroelectrics, X-ray detection, and optoelectronics. The famous metal-free perovskite ferroelectric MDABCO-NH 4 -I 3 (MDABCO = N -methyl- N '-diazabicyclo[2.2.2]octonium) has been demonstrated to exhibit excellent ferroelectricity comparable to that of inorganic ceramic ferroelectric BaTiO 3 , such as large spontaneous polarization and high Curie temperature (Ye et al. Science 2018 , 361 , 151). However, piezoelectricity as a vitally important index is far from enough in the metal-free perovskite family. Here, we report the discovery of large piezoelectric response in a new metal-free three-dimensional perovskite ferroelectric NDABCO-NH 4 -Br 3 (NDABCO = N -amino- N '-diazabicyclo[2.2.2]octonium) by replacing the methyl group of MDABCO with the amino group. Besides the evident ferroelectricity, strikingly, NDABCO-NH 4 -Br 3 shows a large d 33 of 63 pC/N more than 4 times that of MDABCO-NH 4 -I 3 (14 pC/N). The d 33 value is also strongly supported by the computational study. To the best of our knowledge, such a large d 33 value ranks the highest among the documented organic ferroelectric crystals to date and represents a major breakthrough in metal-free perovskite ferroelectrics. Combined with decent mechanical properties, NDABCO-NH 4 -Br 3 is expected to be a competitive candidate for medical, biomechanical, wearable, and body-compatible ferroelectric devices.

Chiral organic-inorganic hybrid semiconductors (COIHSs) dominated by lead halides have recently gained tremendous interest. Here, we report a lead-free photoluminescent COIHS [ R -3-hydroxylpiperidinium] 2 SbCl 5 with a bandgap of 3.14 eV. It shows a ferroelastic phase transition at 341 K accompanied by a switchable second-harmonic generation response and presents clear ferroelastic domains, which are rarely found in lead-free COIHSs.

Piezoelectric materials that enable electromechanical conversion have great application value in actuators, transducers, sensors, and energy harvesters. Large piezoelectric ( d 33 ) and piezoelectric voltage ( g 33 ) coefficients are highly desired and critical to their practical applications. However, obtaining a material with simultaneously large d 33 and g 33 has long been a huge challenge. Here, we reported a hybrid perovskite ferroelectric [Me 3 NCH 2 Cl]CdBrCl 2 to mitigate and roughly address this issue by heavy halogen substitution. The introduction of a large-size halide element softens the metal-halide bonds and reduces the polarization switching barrier, resulting in excellent piezoelectric response with a large d 33 (∼440 pC/N), which realizes a significant optimization compared with that of previously reported [Me 3 NCH 2 Cl]CdCl 3 (You et al. Science 2017 , 357 , 306-309). More strikingly, [Me 3 NCH 2 Cl]CdBrCl 2 simultaneously shows a giant g 33 of 6215 × 10 -3 V m/N, far exceeding those of polymers and conventional piezoelectric ceramics. Combined with simple solution preparation, easy processing of thin films, and a high Curie temperature of 373 K, these attributes make [Me 3 NCH 2 Cl]CdBrCl 2 promising for high-performance piezoelectric sensors in flexible, wearable, and biomechanical devices.

Molecular ferroelectrics with large piezoelectric responses have long been sought for their advantages of light weight, mechanical flexibility, and easy preparation, in contrast to the widely used inorganic counterparts. Representatively, a molecular ferroelectric crystal [Me 3 NCH 2 Cl]CdCl 3 (TMCM-CdCl 3 ) has been found to show a large piezoelectric coefficient d 33 of 220 pC/N exceeding that of BaTiO 3 (You et al. Science 2017 , 357 , 306-309). However, although the d 33 of molecular ferroelectrics has achieved great progress, their electromechanical coupling factor k 33 , which is essential for various piezoelectric applications, including ultrasonic transducers and actuators, was rarely explored and is far below the level of inorganic ferroelectrics. The major reason for this situation is the great challenge of growing large-size crystals which is a key limiting factor for measuring k 33 . Here, we grew inch-size crystals of organic-inorganic perovskite ferroelectric TMCM-CdCl 3 with a high d 33 (383 pC/N) for investigating its piezoelectric responses including the k 33 (0.483) by the resonance method. Such high k 33 (0.483) is much larger than those of other molecular ferroelectrics and competitive with that of BaTiO 3 (0.5). In addition, TMCM-CdCl 3 has a low elastic modulus of 13.03 GPa, an order of magnitude lower than that of BaTiO 3 . This finding sheds light on the exploration of large electromechanical coupling factors in molecular ferroelectrics for potential applications in flexible and portable piezoelectric devices.

Ferroelectricity, existing in either solid crystals or liquid crystals, gained widespread attention from science and industry for over a century. However, ferroelectricity has never been observed in both solid and liquid crystal phases of a material simultaneously. Inorganic ferroelectrics that dominate the market do not have liquid crystal phases because of their completely rigid structure caused by intrinsic chemical bonds. We report a ferroelectric homochiral cholesterol derivative, β-sitosteryl 4-iodocinnamate, where both solid and liquid crystal phases can exhibit the behavior of polarization switching as determined by polarization-voltage hysteresis loops and piezoresponse force microscopy measurements. The unique long molecular chain, sterol structure, and homochirality of β-sitosteryl 4-iodocinnamate molecules enable the formation of polar crystal structures with point group 2 in solid crystal phases, and promote the layered and helical structure in the liquid crystal phase with vertical polarization. Our findings demonstrate a compound that can show the biferroelectricity in both solid and liquid crystal phases, which would inspire further exploration of the interplay between solid and liquid crystal ferroelectric phases., (© 2022. The Author(s).)

Background: Sepsis is one of the most common complications in burn patients and causes high morbidity, especially in those with severe burns. Nevertheless, there are no formal criteria for diagnosing and treating burn sepsis. Therefore, this bibliometric analysis is applied to reveal research trends in this field and predicts its possible hot spots., Methods: We screened relevant literature on burn sepsis that met the inclusion criteria of the Web of Sciences (WOS) database and analyzed publication trends and research hot spots in related fields using VOSviewer software., Results: From 1981 to 2022, we screened 2,486 documents that met the requirements and analyzed them bibliometrically. The American scholar Herndon DN had a much higher h-index [47] than other authors. Most published, cited, and h-indexed publications are from the USA (Np: 1193, Nc: 42154, H: 98). The second most publishing country is China, but the second most cited and h-indexed country is Germany. Burns also outperforms other journals in this field (Np: 376, Nc: 8019, H: 46). "Biomarkers" is a newly emerging keyword (cluster "clinical research," APY was 2018.16), and clinically relevant research in burn sepsis maybe a future research trend., Conclusions: Sepsis in burn patients has unique pathophysiological characteristics and the general diagnostic criteria for sepsis lack specificity. Consequently, we must establish a database and construct an intelligent predictive model to help achieve a more individualized and precise early diagnosis and treatment of burn sepsis. This may also be an important development direction for future research in this field., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Cao, Zhang, Luo, Liao, Cheng and Zhan.)

Organic-inorganic hybrid perovskites (OIHPs) have gained tremendous interest for their rich functional properties. However, the coexistence of more than one of ferroelectricity, ferromagnetism and ferroelasticity has been rarely found in OIHPs. Herein, we report a two-dimensional Cr 2+ -based OIHP, [3,3-difluorocyclobutylammonium] 2 CrCl 4 ([DFCBA] 2 CrCl 4 ), which shows both ferroelectricity and ferromagnetism. It undergoes a 4/mmmFm type ferroelectric phase transition at a temperature as high as 387 K and shows multiaxial ferroelectricity with a saturate polarization of 2.1 μC cm -2 . It acts as a soft ferromagnet with a Curie temperature of 32.6 K. This work throws light on the exploration of OIHPs with the coexistence of ferroelectricity and ferromagnetism for applications in future multifunctional smart devices., (© 2022 Wiley-VCH GmbH.)

A new α-haemolytic streptococcal strain, designated DM3B3 T , was isolated from the wound of a diabetic foot ulcer (DFU) patient. Phylogenetic analysis based on 16S rRNA full-gene sequencing (1563 bp) revealed highest sequence similarity to Streptococcus mitis (99.7%), followed by "Streptococcus gwangjuense" (99.6%), and Streptococcus pseudopneumoniae (99.5%). Comparison of five housekeeping genes, groEL, rpoB, sodA, recA and pheS, revealed that strain DM3B3 T was well separated from the Streptococcus reference strains. The complete genome of strain DM3B3 T consisted of 1,963,039 bp with a G + C content of 41.0 mol%. Average nucleotide identity values between strain DM3B3 T and Streptococcus mitis NCTC 12261 T , "Streptococcus gwangjuense" ChDC B345 T , and Streptococcus pseudopneumoniae ATCC BAA-960 T were 93.8%, 94.4%, and 92.2%, respectively. The highest digital DNA-DNA hybridization value with respect to the closest species was 57.5%, i.e., below the species cut-off of 70% hybridization. The main cellular fatty acids of strain DM3B3 T were 16:0, 18:1ω7c, 18:1ω9c and 18:0. On the basis of phylogenetic, genotypic and phenotypic data, we propose to classify this isolate as representative of a novel species of the genus Streptococcus, Streptococcus vulneris sp. nov., in reference to its isolation from wound, with strain DM3B3 T (= NBRC 114638 T  = BCRC 81288 T ) as the type strain., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Two new hasubanan alkaloids, stephalonester A ( 1 ) and stephalonester B ( 2 ), together with four known compounds, stephalonine E ( 3 ), longanone ( 4 ), cephatonine ( 5 ), and prostephabyssine ( 6 ) were isolated from the whole plant of Stephania longa . Their structures were determined by HR-ESI-MS, 1 D and 2 D NMR, ECD calculations, as well as by comparison with literature values. All compounds were evaluated for their anti-inflammatory activity in vitro. Compounds 4 , 5 , and 6 exhibited significantly inhibitory effects on TNF-α and IL-6 production with IC 50 values range from 6.54 to 30.44 µM.

Shape memory alloys have been used extensively in actuators, couplings, medical guide wires, and smart devices, because of their unique shape memory effect and superelasticity triggered by the reversible martensitic phase transformations. For ferroic materials, however, almost no memory effects have been found for their ferroic domains after reversible phase transformations. Here, we present a pair of single-component organic enantiomorphic ferroelectric/ferroelastic crystals, (R)- and (S)-N-3,5-di-tert-butylsalicylidene-1-(1-naphthyl)ethylamine SA-NPh-(R) and SA-NPh-(S). It is notable that not only can their ferroic domain patterns disappear and reappear during reversible thermodynamic phase transformations, but they can also disappear and reappear during reversible light-driven phase transformations induced by enol-keto photoisomerization, both of which are from P1 to P2 1 polar space groups. Most importantly, the domain patterns are exactly the same in the initial and final states, demonstrating the existence of a memory effect for the ferroic domains in SA-NPh-(R) and SA-NPh-(S). As far as we are aware, the domain memory effect triggered by both thermodynamic and light-driven ferroelectric/ferroelastic phase transformations remains unexplored in ferroic materials. Thermal and optical control of domain memory effect would open up a fresh research field for smart ferroic materials., (© 2022. The Author(s).)

Three arecophila-like fungal samples were collected on dead culms of gramineous plants in China. Morphological studies of our new collections and the herbarium specimen of Arecophilagulubiicola (generic type) were conducted and the morphological affinity of our new collections with Arecophila was confirmed. Maximum likelihood and Bayesian analyses using combined ITS, LSU, rpb 2 and β-tubulin data from our collections revealed the phylogeny of Cainiaceae . The monospecific genus Alishanica (type species Al.miscanthi ), which had been accepted in Cainiaceae , is revisited and synonymised under Arecophila . Based on morphology and phylogeny, Arecophilaaustralis sp. nov. and A.clypeata sp. nov. are introduced as new species, while A.miscanthi is a new record for China. All the new collections are illustrated and described., (Qi Rui Li, Xu Zhang, Yan Lin, Milan C. Samarakoon, Kevin David Hyde, Xiang Chun Shen, Wan Qing Liao, Anuruddha Karunarathna, Si Han Long, Ying Qian Kang, Ji Chuan Kang.)

Organic single-component ferroelectrics, as an important class of metal-free ferroelectrics, are highly desirable because of their easy processing, mechanical flexibility, and biocompatibility. However, although nearly 50 years have passed since the discovery of photochromism in azobenzene-doped cholesteric liquid crystals, ferroelectricity has never been found in azobenzene-based crystals. Here, we use an amino group to substitute a fluorine atom of 2,2',4,4',6,6'-hexafluoroazobenzene, which successfully introduces ferroelectricity into 2-amino-2',4,4',6,6'-pentafluoroazobenzene (APFA). APFA shows an extremely high Curie temperature ( T c ) of 443 K, which is outstanding among single-component ferroelectrics. It also exhibits an indirect optical band gap of 2.27 eV as well as photoisomerization behavior between the trans -form and the cis -form triggered by pedal motion. To our knowledge, APFA is the first azobenzene-based ferroelectric crystal. This work opens an avenue to design excellent single-component ferroelectrics and will inspire the exploration of azobenzene-based ferroelectrics for promising applications in biofriendly ferroelectric devices., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A four-ingredient polymer chain has record-breaking piezoelectric capability.

Aim: This study aims to provide reliable prognostic factors for patients with cryptococcal meningitis (CM). Patients & methods: Clinical characteristics and laboratory findings of CM patients were retrospectively reviewed. Results: Sixty-three patients with CM were enrolled and 38/63 were confirmed to be HIV serology positive. Among clinical characteristics, headache, nausea and/or vomiting, and fever were the most common symptoms. Among cerebrospinal fluid (CSF) parameters, changes in leukocyte count, lactate dehydrogenase and chloride were significantly associated with the outcome. An increased CSF/serum albumin quotient (QAlb) was indicative of an unfavorable outcome in HIV-negative patients. Conclusion: CSF lactate dehydrogenase and QAlb may improve the prediction of outcomes in patients with CM.

A ferroelectric/ferroelastic is a material whose spontaneous polarization/strain can be switched by applying an external electric field/mechanical stress. However, the optical control of spontaneous polarization/strain remains relatively unexplored in crystalline materials, although photoirradiation stands out as a nondestructive, noncontact, and remote-controlled stimulus beyond stress or electric field. Here, we present two new organic single-component homochiral photochromic multiferroics, ( R )- and ( S )- N -3,5-di- tert -butylsalicylidene-1-4-bromophenylethylamine (SA-Ph-Br( R ) and SA-Ph-Br( S )), which show a full ferroelectric/ferroelastic phase transition of 222F2 type at 336 K. Under photoirradiation, their spontaneous polarization/strain can be switched quickly within seconds and reversibly between two ferroelectric/ferroelastic phases with the respective enol and trans -keto forms triggered by structural photoisomerizations. In addition, they possess a superior acoustic impedance characteristic with a value of ∼2.42 × 10 6 kg·s -1 ·m -2 , lower than that of polyvinylidene fluoride (PVDF, (3.69-4.25) × 10 6 kg·s -1 ·m -2 ), which can better match human tissues. This work realizes for the first time that multiple ferroic orders in single-component organic crystals with ultralow acoustic impedance can be simultaneously controlled and coupled by three physical channels (electric, stress, light fields), suggesting their great potential in multichannel data storage, optoelectronics, and related applications compatible with all-organic electronics and human tissues.

Ferroelectrics usually exhibit temperature-triggered structural changes, which play crucial roles in controlling their physical properties. However, although light is very striking as a non-contact, non-destructive, and remotely controlled external stimuli, ferroelectric crystals with light-triggered structural changes are very rare, which holds promise for optical control of ferroelectric properties. Here, an organic molecular ferroelectric, N-salicylidene-2,3,4,5,6-pentafluoroaniline (SA-PFA), which shows light-triggered structural change of reversible photoisomerization between cis-enol and trans-keto configuration is reported. SA-PFA presents clear ferroelectricity with the saturate polarization of 0.84 μC cm -2 , larger than those of some typical organic ferroelectrics with thermodynamically structural changes. Benefit from the reversible photoisomerization, the dielectric real part of SA-PFA can be reversibly switched by light. More strikingly, the photoisomerization enables SA-PFA to show reversible optically induced ferroelectric polarization switching. Such intriguing behaviors make SPFA a potential candidate for application in next-generation photo-controlled ferroelectric devices. This work sheds light on further exploration of more excellent molecular ferroelectrics with light-triggered structural changes for optical control of ferroelectric properties., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Sequences targeted at the V3 and V4 16S rRNA hypervariable regions of a streptococcal strain (P1L01 T ) isolated from vaginal swabs of a pregnant woman with diabetes were 100% similar to those of Streptococcus anginosus subsp. whileyi. However, phylogenetic analysis based on 16S rRNA full-gene sequencing (1562 bp) revealed highest sequence similarity to Streptococcus periodonticum (98.7%), followed by Streptococcus anginosus subsp. whileyi (98.7%), and Streptococcus anginosus subsp. anginosus (98.4%). Phylogenies of housekeeping genes rpoB and groEL were compared to improve classification, and the results showed a clear separation between strain P1L01 T and closely related Streptococcus type strains. The complete genome of strain P1L01 T consisted of 2,108,769 bp with a G + C content of 38.5 mol%. Average nucleotide identity values, based on genome sequencing, between strain P1L01 T and Streptococcus periodonticum KCOM 2412 T , Streptococcus anginosus subsp. whileyi CCUG 39159 T , and Streptococcus anginosus subsp. anginosus NCTC 10713 T were 95.5%, 94.3%, and 95.3%, respectively. The highest in silico DNA-DNA hybridization value with respect to the closest species was 66.2%, i.e., below the species cutoff of 70% hybridization. The main cellular fatty acids of strain P1L01 T were 16:0, 18:1ω7c, and 14:0. On the basis of phylogenetic, genotypic and phenotypic data, we propose to classify this isolate as representative of a novel species of the genus Streptococcus, Streptococcus vaginalis sp. nov., in reference to its isolation from vaginal swabs, with strain P1L01 T (= NBRC 114754 T  = BCRC 81289 T ) as the type strain., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study analyzed the in vitro drug sensitivity of Cryptococcus spp. from Guangxi, Southern China. One hundred three strains of Cryptococcus were recovered from 86 patients; 14 were HIV positive and 72 were HIV negative. Ninety-two strains were identified as Cryptococcus neoformans var. grubii , while 11 strains were identified as Cryptococcus gattii (5 C. gattii sensu stricto and 6 Cryptococcus deuterogattii ). The recovered strains were tested against commonly used antifungal drugs (fluconazole, amphotericin B, 5-fluorocytosine, itraconazole, and voriconazole) and to novel antifungal drugs (posaconazole and isavuconazole) using CLSI M27-A4 method. The results showed that all isolates were susceptible to most antifungal drugs, of which the minimum inhibitory concentration (MIC) ranges were as follows: 0.05-4 μg/ml for fluconazole, 0.25-1 μg/ml for amphotericin B; 0.0625-2 μg/ml for 5-fluorocytosine, 0.0625-0.25 μg/ml for itraconazole, 0.0078-0.25 μg/ml for voriconazole, 0.0313-0.5 μg/ml for posaconazole, 0.0020-0.125 μg/ml for isavuconazole for C. neoformans var. grubii isolates, and 1-16 μg/ml for fluconazole, 0.125-1 μg/ml for 5-fluorocytosine, 0.25-1 μg/ml for amphotericin B, 0.0625-0.25 μg/ml for itraconazole, 0.0156-0.125 μg/ml for voriconazole, 0.0156-0.25 μg/ml for posaconazole, and 0.0078-0.125 μg/ml for isavuconazole for C. gattii isolates. Furthermore, some C. neoformans var. grubii isolates were found to be susceptible-dose dependent to 5-fluorocytosine and itraconazole. In addition, a reduction in the potency of fluconazole against C. gattii is possible. We observed no statistical differences in susceptibility of C. neoformans var. grubii and C. gattii in the tested strains. Continuous observation of antifungal susceptibility of Cryptococcus isolates is recommended to monitor the emergence of resistant strains., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Al-Odaini, Li, Li, Chen, Huang, Lv, Pan, Zheng, Zheng, Liao and Cao.)

With prosperity, decay, and another spring, molecular ferroelectrics have passed a hundred years since Valasek first discovered ferroelectricity in the molecular compound Rochelle salt. Recently, the proposal of ferroelectrochemistry has injected new vigor into this century-old research field. It should be highlighted that piezoresponse force microscopy (PFM) technique, as a non-destructive imaging and manipulation method for ferroelectric domains at the nanoscale, can significantly speed up the design rate of molecular ferroelectrics as well as enhance the ferroelectric and piezoelectric performances relying on domain engineering. Herein, we provide a brief review of the contribution of the PFM technique toward assisting the design and performance optimization of molecular ferroelectrics. Relying on the relationship between ferroelectric domains and crystallography, together with other physical characteristics such as domain switching and piezoelectricity, we believe that the PFM technique can be effectively applied to assist the design of high-performance molecular ferroelectrics equipped with multifunctionality, and thereby facilitate their practical utilization in optics, electronics, magnetics, thermotics, and mechanics among others.

The well-developed design strategy of molecular modification for assembling molecular ferroelectrics mainly focuses on the cations. Herein, by homochiral anionic modification of the non-ferroelectric (quinuclidinium)(HSO 4 ), we designed high-temperature multiaxial organic enantiomeric ferroelectrics, (quinuclidinium)(l- and d-camphorsulfonate). This work paves a new road for precisely constructing excellent molecular ferroelectrics.

Objective: Bladder urothelial carcinoma (BUC) is a common urological malignancy with molecular heterogeneity. However, the genetic feature of Chinese BUC patients is still not well-identified., Methods: We performed deep sequencing by a large panel (450 genes) on 22 BUC samples and using matched normal bladder tissue as control. Genomic alterations (GAs), pathways and Tumor Mutation Burden (TMB) were investigated., Results: The frequencies of GAs ( TERT , 54.5%; CREBBP , 27.3%; GATA3 , 22.7%; BRAF , 18.2%; TEK , 18.2% and GLI1 , 18.2%) were significantly higher in Chinese than Western BUC patients. Other GAs' frequencies were in accordance with previous study ( TP53 , 50.0%; KDM6A , 31.8%; KMT2D , 22.7%; etc.). Besides, we detected gene amplification in ERBB2, FRS2, FAS , etc. The gene fusion/rearrangement took place in the chromosome 11, 12, 14, 17, 19, 22, and Y. Other than cell cycle and PI3K-AKT-mTOR, mutated genes were more associated with the transcription factor, chromatin modification signaling pathways. Interestingly, the TMB value was significantly higher in the BUC patients at stages T1-T2 than T3-T4 ( P = 0.025)., Conclusion: Deep genomic sequencing of BUC can provide new clues on the unique GAs of Chinese patients and assist in therapeutic decision., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Li, Yang, Liao, Zhou, Li, Cai, Liu, Luo and Zhan.)

Transcriptome differences between Hodgkin's lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), and mantle cell lymphoma (MCL), which are all derived from B cell, remained unclear. This study aimed to construct lymphoma-specific diagnostic models by screening lymphoma marker genes. Transcriptome data of HL, DLBCL, and MCL were obtained from public databases. Lymphoma marker genes were screened by comparing cases and controls as well as the intergroup differences among lymphomas. A total of 9 HL marker genes, 7 DLBCL marker genes, and 4 MCL marker genes were screened in this study. Most HL marker genes were upregulated, whereas DLBCL and MCL marker genes were downregulated compared to controls. The optimal HL-specific diagnostic model contains one marker gene (MYH2) with an AUC of 0.901. The optimal DLBCL-specific diagnostic model contains 7 marker genes (LIPF, CCDC144B, PRO2964, PHF1, SFTPA2, NTS, and HP) with an AUC of 0.951. The optimal MCL-specific diagnostic model contains 3 marker genes (IGLV3-19, IGKV4-1, and PRB3) with an AUC of 0.843. The present study reveals the transcriptome data-based differences between HL, DLBCL, and MCL, when combined with other clinical markers, may help the clinical diagnosis and prognosis.

Organic-inorganic metal halide ferroelectric semiconductors are mainly lead halide ones, suffering from the presence of toxic lead. Herein, we report a lead-free bismuth iodide ferroelectric semiconductor [1,4-butanediammonium]BiI5, showing a high Curie temperature of 365 K and a small band gap of 1.95 eV, smaller than those of most lead halide counterparts.

Organic ferroelectrics are attracting tremendous interest because of their mechanical flexibility, ease of fabrication, and low acoustical impedance. Although great advances have been made in recent years, topological defects such as vortices remain relatively unexplored in the organic ferroelectric system. Here, from [quinuclidinium]ReO 4 ([Q]ReO 4 ), we applied the molecular design strategy of H/F substitution to successfully synthesize the organic ferroelectric [4-fluoroquinuclidinium]ReO 4 ([4-F-Q]ReO 4 ). Through H/F substitution, the Curie temperature and spontaneous polarization are respectively increased from 367 K and 5.83 μC/cm 2 in [Q]ReO 4 to 466 K and 11.37 μC/cm 2 in [4-F-Q]ReO 4 . Moreover, under mechanical stress fields, three kinds of stripelike domains with various polarization directions emerge to form a windmill-like domain pattern in the thin film of [4-F-Q]ReO 4 , in which intriguing vortex-antivortex topological configurations can exist stably. This work provides an efficient strategy for optimizing the properties of organic ferroelectrics and exploring emergent phenomena.

The nonradiative recombination of electrons and holes has been identified as the main cause of energy loss in hybrid organic-inorganic perovskite solar cells (PSCs). Sufficient built-in field and defect passivation can facilitate effective separation of electron-hole pairs to address the crucial issues. For the first time, we introduce a homochiral molecular ferroelectric into a PSC to enlarge the built-in electric field of the perovskite film, thereby facilitating effective charge separation and transportation. As a consequence of similarities in ionic structure, the molecular ferroelectric component of the PSC passivates the defects in the active perovskite layers, thereby inducing an approximately eightfold enhancement in photoluminescence intensity and reducing electron trap-state density. The photovoltaic molecular ferroelectric PSCs achieve a power conversion efficiency as high as 21.78 %., (© 2020 Wiley-VCH GmbH.)

Through the strategy of F/H substitution, we precisely designed the highest-Tc (phase transition temperature) organic enantiomeric ferroelectrics, (R)- and (S)-(N,N-dimethyl-3-fluoropyrrolidinium) iodide, of which the Tc reaches up to 470 K, far beyond those of other enantiomeric ferroelectrics and also the commercial ferroelectric BaTiO3.

Switchable materials play an invaluable role in signal processing and encryption of smart devices. The development of multifunctional materials that exhibit switching characteristics in multiple physical channels has attracted widespread attention. Now, two chiral thermochromic ferroelastic crystals (S-CTA) 2 CuCl 4 and (R-CTA) 2 CuCl 4 (CTA=3-chloro-2-hydroxypropyltrimethylammonium) have been prepared with switchable properties in dielectricity, conductivity, second harmonic generation (SHG), piezoelectricity, ferroelasticity, chiral, and thermochromic properties. Compared with traditional phase-transition materials with switching features, thermochromism brings additional spectral encryption possibilities for future information processing. To the best of our knowledge, this is the first chiral thermochromic ferroelastic that exhibits switching properties in seven physical channels. This work is expected to promote further exploration of multifunctional molecular switchable materials., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Chiral organic-inorganic perovskites (COIPs) have recently attracted increasing interest due to their unique inherent chirality and potential applications in next-generation optoelectronic and spintronic devices. However, COIP ferroelectrics are very sparse. In this work, for the first time, we present the nickel-nitrite ABX 3 COIP ferroelectrics, [( R and S )- N -fluoromethyl-3-quinuclidinol]Ni(NO 2 ) 3 ([( R and S )-FMQ]Ni(NO 2 ) 3 ), where the X-site is the rarely seen NO 2 - bridging ligand. [( R and S )-FMQ]Ni(NO 2 ) 3 display mirror-relationship in the crystal structure and vibrational circular dichroism signal. It is emphasized that [( R and S )-FMQ]Ni(NO 2 ) 3 show splendid ferroelectricity with both an extremely high phase-transition point of 405 K and a spontaneous polarization of 12 μC/cm 2 . To our knowledge, [( R and S )-FMQ]Ni(NO 2 ) 3 are the first examples of nickel-nitrite based COIP ferroelectrics. This finding expands the COIP family and throws light on exploration of high-performance COIP ferroelectrics.

Organic-inorganic ABX 3 (A, B = cations, X = anion) hybrids with perovskite structure have recently attracted tremendous interest due to their structural tunability and rich functional properties, such as ferroelectricity. However, ABX 3 hybrid ferroelectrics with other structures have rarely been reported. Here, we successfully designed an ABX 3 hybrid ferroelectric [(CH 3 ) 3 NCH 2 F]ZnCl 3 with a spontaneous polarization of 4.8 μC/cm 2 by the molecular modification of [(CH 3 ) 4 N]ZnCl 3 through hydrogen/halogen substitution. It is the first zinc halide ABX 3 ferroelectric, which contains one-dimensional [ZnCl 3 ] - n chains of corner-sharing ZnCl 4 tetrahedra, distinct from the anionic framework of corner-sharing or face-sharing BX 6 octahedra in the ABX 3 perovskites. From zero dimension to one dimension, the high symmetry of ZnCl 4 tetrahedra is broken, and all of them align along one direction to form a polar [ZnCl 3 ] - n chain, beneficial to the generation of ferroelectricity. This finding provides an efficient polar anionic framework for enriching the family of hybrid ferroelectrics by assembling with various cations and should inspire further exploration of new classes of organic-inorganic ABX 3 ferroelectrics.

Three-dimensional (3D) organic-inorganic lead halides represented by [CH 3 NH 3 ]PbI 3 perovskite have attracted great interest for their diverse functional properties and promising optoelectronic applications. However, 3D lead halides are still very rare and their ferroelectricity remains controversial. Here, we report an unprecedented 3D lead halide perovskite-related ferroelectric [2-trimethylammonioethylammonium]Pb 2 Cl 6 ([TMAEA]Pb 2 Cl 6 ), which contains a 3D lead chloride framework of corner- and edge-sharing PbCl 6 octahedral, with the [TMAEA] + cations occupying the voids of the framework. [TMAEA]Pb 2 Cl 6 shows a ferroelectric-to-paraelectric phase transition with the Curie temperature as high as 412 K, a typical ferroelectric hysteresis loop at 293 K with a spontaneous polarization of 1 μC/cm 2 , and a clear ferroelectric domain switching. To the best of our knowledge, [TMAEA]Pb 2 Cl 6 is the first 3D lead halide showing such an excellent ferroelectricity. Additionally, it also exhibits a semiconducting property with a direct band gap of 3.43 eV. This finding enriches the family of 3D hybrid lead halides and inspires the exploration of 3D lead halide ferroelectrics.

Molecular ferroelectrics have attracted considerable interests because of their easy and environmentally friendly processing, low acoustical impedance and mechanical flexibility. Herein, a molecular thermochromic ferroelectric, N,N'-dimethyl-1,4-diazoniabicyclo[2.2.2]octonium tetrachlorocuprate(II) ([DMe-DABCO]CuCl 4 ) is reported, which shows both excellent ferroelectricity and intriguing thermochromism. [DMe-DABCO]CuCl 4 undergoes a ferroelectric phase transition from Pca2 1 to Pbcm at a significantly high Curie temperature of 413 K, accompanied by a color change from yellow to red that is due to the remarkable deformation of [CuCl 4 ] 2- tetrahedron, where the ferroelectric and paraelectric phases correspond to yellow and red, respectively. Combined with multiple bistable physical properties, [DMe-DABCO]CuCl 4 would be a promising candidate for next-generation smart devices, and should inspire further exploration of multifunctional molecular ferroelectrics., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Molecular ferroelectrics as alternatives to the conventional inorganic ferroelectrics have been greatly developed in past decades; many of these have been discovered and designed through various chemical means due to their structural adjustability. However, it is still a huge challenge to obtain high (above room temperature) Curie temperature ( T c ) molecular ferroelectrics to meet the application requirements. Here, we present a new organic-inorganic hybrid molecular ferroelectric, [cyclopentylammonium] 2 CdBr 4 ( 1 ), showing a moderate above-room-temperature T c of 340.3 K. The mechanism of the ferroelectric phase transition from Pnam to Pna 2 1 in 1 is ascribed to the order-disorder transition of both the organic cations and inorganic anions, affording a spontaneous polarization of 0.57 μC/cm 2 for the ferroelectric phase. Using piezoresponse force microscopy (PFM), we clearly observed the antiparallel 180° stripe domains and realized the polarization switching, unambiguously establishing the existence of room-temperature ferroelectricity in the thin film. These attributes make it attractive for use in flexible devices, soft robotics, biomedical devices, and other applications.

Since the first perovskite CaTiO 3 was discovered in 1839, the development of perovskite has a history of 180 years. The emergence of solar cells (CH 3 NH 3 )PbI 3 has set off the trend of hybrid organic-inorganic perovskite (HOIP) materials. Since then, various HOIPs have sprung up and been widely used in various material devices. Among them, HOIP ferroelectrics have gained widespread attention. However, antiperovskite, as a twin brother of perovskite, has been neglected although it has similar structure with perovskite. Here, we successfully found that [C 3 H 7 FN] 3 [SnCl 6 ]Cl has a three-dimensional (3D) antiperovskite structure with the formula M 3 AB. Importantly, the compound exhibits obvious ferroelectric properties with an Aizu notation of 622F6 at 391 K. To the best of our knowledge, this is the first 3D hybrid organic-inorganic antiperovskite ferroelectric, which will greatly promote the development of antiperovskite families with more superior physical properties., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two-dimensional (2D) organic-inorganic perovskites (OIPs), with improved material stability over their 3D counterparts, are highly desirable for device applications. It is their considerable structural diversity that offers an unprecedented opportunity to engineer materials with fine-tuning functionalities. The isosteric substitution of hydrogen by an electronegative fluorine atom has been proposed as a useful route to improve the photovoltaic performance of 2D OIPs, whereas its valuable role in developing ferroelectricity is still waiting for further exploration. Herein, for the first time we applied fluorinated aromatic cations in extending the family of 2D OIP ferroelectrics, and successfully obtained [2-fluorobenzylammonium] 2 PbCl 4 as a high-performance ferroelectric semiconductor. The failures in the nonferroelectric [4-fluorobenzylammonium] 2 PbCl 4 and [3-fluorobenzylammonium] 2 PbCl 4 demonstrate that the selective introduction of fluorine in correct structural positions is particularly essential. This work represents an unprecedented proof-of-concept in the use of fluorinated aromatic cations for the targeted design of excellent 2D OIP ferroelectrics, and is believed to inspire the future development of low-cost, high-efficiency, and stable device applications.

Molecular optical-dielectric duple bistable switches are photoelectric (dielectric and fluorescent) multifunctional materials that can simultaneously convert optical and electrical signals in one device for seamless integration. However, exploring optical-dielectric duple channels of dielectric and photoluminescence is still a bigger challenge than single dielectric or photoluminescence bistable ones, which are hardly reported but probably will be heavily researched owing to the new generation artificial intelligence development needs in the future. Herein, a new optical-dielectric duple bistable switches material, [(CH 3 ) 3 NCH 2 CH 3 ] 2 MnCl 4 (I), was obtained by a simple method for volatilization of solvents. Variable temperature single crystal X-ray analysis indicates that material I has a reversible bistable structure (order-disorder structure phase transition) corresponding to switching "ON'' and "OFF''. Unlike the single dielectric bistable structures that were previously reported, material I also own bistable features in terms of fluorescence property. This material enriches the specific examples of photoelectric duple function switch materials and facilitates the development of required devices., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)