Chemical order-disorder nanodomains in Fe3Pt bulk alloy

Chemical ordering is a common phenomenon and highly correlated with the properties of solid materials. By means of the redistribution of atoms and chemical bonds, it invokes an effective lattice adjustment and tailors corresponding physical properties. To date, however, directly probing the 3D interfacial interactions of chemical ordering remains a big challenge. In this work, we deciphered the interlaced distribution of nanosized domains with chemical order/disorder in Fe₃Pt bulk alloy. HAADF-STEM images evidence the existence of such nanodomains. The reverse Monte Carlo method with the X-ray pair distribution function data reveal the 3D distribution of local structures and the tensile effect in the disordered domains at the single-atomic level. The chemical bonding around the domain boundary changes the bonding feature in the disordered side and reduces the local magnetic moment of Fe atoms. This results in a suppressed negative thermal expansion and extended temperature range in Fe₃Pt bulk alloy with nanodomains. Our study demonstrates a local revelation for the chemical order/disorder nanodomains in bulk alloy. The understanding gained from atomic short-range interactions within the domain boundaries provides useful insights with regard to designing new functional compounds.

Chemical Diversity for Tailoring Negative Thermal Expansion

Negative thermal expansion (NTE), referring to the lattice contraction upon heating, has been an attractive topic of solid-state chemistry and functional materials. The response of a lattice to the temperature field is deeply rooted in its structural features and is inseparable from the physical properties. For the past 30 years, great efforts have been made to search for NTE compounds and control NTE performance. The demands of different applications give rise to the prominent development of new NTE systems covering multifarious chemical substances and many preparation routes. Even so, the intelligent design of NTE structures and efficient tailoring for lattice thermal expansion are still challenging. However, the diverse chemical routes to synthesize target compounds with featured structures provide a large number of strategies to achieve the desirable NTE behaviors with related properties. The chemical diversity is reflected in the wide regulating scale, flexible ways of introduction, and abundant structure-function insights. It inspires the rapid growth of new functional NTE compounds and understanding of the physical origins. In this review, we provide a systematic overview of the recent progress of chemical diversity in the tailoring of NTE. The efficient control of lattice and deep structural deciphering are carefully discussed. This comprehensive summary and perspective for chemical diversity are helpful to promote the creation of functional zero-thermal-expansion (ZTE) compounds and the practical utilization of NTE.

BMSC-Derived ApoEVs Promote Craniofacial Bone Repair via ROS/JNK Signaling

Bone defect caused by trauma, neoplasia, congenital defects, or periodontal disease is a major cause of disability and physical limitation. The transplantation of bone marrow mesenchymal stem cells (BMSCs) promotes bone repair and regeneration. However, it has been shown that most BMSCs die within a short period after transplantation. During apoptosis, BMSCs generate a large number of apoptotic cell-derived extracellular vesicles (ApoEVs). This study aims to understand the potential role of ApoEVs in craniofacial bone defect repair and regeneration. First, we confirmed that BMSCs undergo apoptosis within 2 d after transplantation into the defect of the cranium. Abundant ApoEVs were generated from apoptotic BMSCs. Uptake of ApoEVs efficiently promoted the proliferation, migration, and osteogenic differentiation of recipient BMSCs in vitro. ApoEVs from cells in the middle stage of apoptosis were the most efficient to enhance the regenerative capacity of BMSCs. Moreover, a critical size bone defect model in rats was used to evaluate the osteogenic property of ApoEVs in vivo. Local transplantation of ApoEVs promoted bone regeneration in the calvarial defect. Mechanistically, ApoEVs promoted new bone formation by increasing intracellular reactive oxygen species to activate JNK signaling. This study reveals a previously unknown role of the dying transplanted BMSCs in promoting the viability of endogenous BMSCs and repairing the calvarial defects. Since it could avoid several adverse effects and limits of BMSC cytotherapy, treatment of ApoEVs might be a promising strategy in craniofacial bone repair and regeneration.

Structure, electrical properties, and conduction mechanism of new germanate mixed Zn-doped In2Ge2O7 conductors

A new germanate mixed electronic and oxide ionic conductor In1.8Zn0.2Ge2O6.9 was developed, which exhibits two-dimensional anisotropic transport nature by oxygen exchange between adjacent Ge2O7 units, with a conductivity of 1.62 × 10–2 S cm−1 at 1000 °C.

Anomalous Thermal Expansion of Strontium Squarate Trihydrate Induced by Hydrogen-bond Weakening

The blending of various chemical bonds with different strengths within a framework is expected to induce some anomalous physical properties. Herein, a novel metal squarate framework containing covalent bonds, coordination...

A theoretical approach for homogeneous CO2 reduction by Ni(cyclam): substituents with intra-molecular hydrogen transfer

The detailed mechanism reveals the deep relationship of reaction activity with acidity, substituent nature (at position 1 or 2), and conformation in CO2 reduction.

Oxygen vacancy distributions and electron localization in a CeO2(100) nanocube

Oxygen vacancy distributions in a 5 nm CeO2 nanocube were determined using the Reverse Monte Carlo method. The oxygen vacancies tend to be located on the surface of the CeO2 nanocube, with far fewer in subsurface and internal regions.

Intrinsic volumetric negative thermal expansion in the "rigid" calcium squarate

The calcium squarate with a rigid framework is found to exhibit volumetric negative thermal expansion (NTE) with the coefficient -9.51(5) × 10^-6 K^-1 and uniaxial zero thermal expansion (ZTE, -0.14(4) × 10^-6 K^-1) over a wide temperature. Detailed comparison of the long-range and local structure sheds light on the fact that the anomalous thermal expansion originates from the transverse vibration of the bridging squarate ligand, although it has been tightly bonded by five calcium ions. We believe that this study can provide a deep insight into the origin of NTE and the structural flexibility of metal organic frameworks (MOFs).

Correlation of Tunable CoSi4 Tetrahedron with the Superconducting Properties of LaCoSi

It is known that as the FeAs4 tetrahedron in the Fe-based superconductor is close to the regular tetrahedron, critical temperature (Tc) can be greatly increased. Recently, a Co-based superconductor of LaCoSi (4 K) with "111" structure was found. In this work, we improve the Tc of LaCoSi through structural regulation. Tc can be increased by the chemical substitution of Co by Fe, while the superconductivity is suppressed by the Ni substitution. The combined analysis of neutron and synchrotron X-ray powder diffractions reveals that the change of the Si-Co-Si bond angles of the CoSi4 tetrahedron is possibly responsible for the determination of superconducting properties. The Fe chemical substitution is favorable for the formation of the regular tetrahedron of CoSi4. The present new Co-based superconductor of LaCoSi provides a possible method to enhance the superconductivity performance of the Co-based superconductors via controlling Co-based tetrahedra similar to those well established in the Fe-based superconductors.

Safety and efficacy of common vitamin D supplementation in primary hyperparathyroidism and coexistent vitamin D deficiency and insufficiency: a systematic review and meta-analysis

PURPOSE

Primary hyperparathyroidism (PHPT) is characterized by excessive secretion of parathyroid hormone (PTH). Vitamin D deficiency can stimulate parathyroid secretion. However, whether to correct vitamin D deficiency in patients with PHPT is controversial. We aimed to evaluate the safety and efficacy of vitamin D replacement in patients with PHPT.

METHODS

We searched PubMed, Cochrane Library, and Embase. The relevant data were extracted from the included documents. The methodological items for non-randomized studies score entries were used for evaluation of quality. Review Manager 5.3 and Stata 12.0 were used for statistical analysis.

RESULTS

A total of 11 articles were included with a total of 388 patients. The serum calcium mean difference (MD) was - 0.06 mg/dL [95% confidence interval (95% CI) - 0.16, 0.04]. Subgroup analysis showed that serum calcium levels did not change if the intervention time exceeded 1 month. The 24-h urinary calcium MD was 36.78 mg/day (95% CI - 37.15, 110.71), which indicated that there was no significant effect of vitamin D supplementation on 24-h urinary calcium levels. The MD of PTH was - 16.01 pg/mL (95% CI - 28.79, - 3.24). Subgroup analysis according to the intervention time showed that vitamin D intervention for more than 1 month significantly reduced PTH levels. The ALP MD was - 10.81 U/L (95% CI - 13.98, - 7.63), which indicated Vitamin D supplementation reduced its level. The MD of 25-hydroxyvitamin D was 22.09 μg/L (95% CI 15.01, 29.17), and no source of heterogeneity was found.

CONCLUSION

Vitamin D supplementation in patients with PHPT and vitamin D deficiency significantly reduces PTH and ALP levels without causing hypercalcemia and hypercalciuria.

Ultrawide Temperature Range Super-Invar Behavior of R_{2}(Fe,Co)_{17} Materials (R = Rare Earth)

Super Invar (SIV), i.e., zero thermal expansion of metallic materials underpinned by magnetic ordering, is of great practical merit for a wide range of high precision engineering. However, the relatively narrow temperature window of SIV in most materials restricts its potential applications in many critical fields. Here, we demonstrate the controlled design of thermal expansion in a family of R_{2}(Fe,Co)_{17} materials (R=rare Earth). We find that adjusting the Fe-Co content tunes the thermal expansion behavior and its optimization leads to a record-wide SIV with good cyclic stability from 3-461 K, almost twice the range of currently known SIV. In situ neutron diffraction, Mössbauer spectra and first-principles calculations reveal the 3d bonding state transition of the Fe-sublattice favors extra lattice stress upon magnetic ordering. On the other hand, Co content induces a dramatic enhancement of the internal molecular field, which can be manipulated to achieve "ultrawide" SIV over broad temperature, composition and magnetic field windows. These findings pave the way for exploiting thermal-expansion-control engineering and related functional materials.

Zero Thermal Expansion and Strong Covalent Binding of VB2 Compound

Zero thermal expansion (ZTE) is an intriguing phenomenon by virtue of its peculiar lack of expansion and contraction with temperature. The achievement of ZTE in a metallic material is a desired but challenging task. Here we report the ZTE behavior of a single-phase metallic VB₂ compound, stacking with the V and B atomic layers along the c direction (α_V = 2.18 × 10^-6 K^-1, 5-150 K). Neutron powder diffraction demonstrates that the ZTE behavior is entangled in the direct blocking of the lattice expansion along all crystallographic directions with temperature. X-ray photoelectron spectroscopy and density functional theory calculations indicate that strong covalent binding adheres the nearest-neighbor B-B and V-B pairs, which is proposed to control the ZTE within both the basal plane and the c direction. An intimate correlation is revealed between the covalent binding and the lattice parameters. Our work indicates the opportunity to design metallic ZTE with strong chemical binding in the future.

Chemical-Pressure-Modulated BaTiO3 Thin Films with Large Spontaneous Polarization and High Curie Temperature

Although BaTiO₃ is one of the most famous lead-free piezomaterials, it suffers from small spontaneous and low Curie temperature. Chemical pressure, as a mild way to modulate the structures and properties of materials by element doping, has been utilized to enhance the ferroelectricity of BaTiO₃ but is not efficient enough. Here, we report a promoted chemical pressure route to prepare high-performance BaTiO₃ films, achieving the highest remanent polarization, P_r (100 μC/cm²), to date and high Curie temperature, T_c (above 1000 °C). The negative chemical pressure (∼-5.7 GPa) was imposed by the coherent lattice strain from large cubic BaO to small tetragonal BaTiO₃, generating high tetragonality (c/a = 1.12) and facilitating large displacements of Ti. Such negative pressure is especially significant to the bonding states, i.e., hybridization of Ba 5p-O 2p, whereas ionic bonding in bulk and strong bonding of Ti e_g and O 2p, which contribute to the tremendously enhanced polarization. The promoted chemical pressure method shows general potential in improving ferroelectric and other functional materials.

Superconductivity in Co-Layered LaCoSi

It is known that few Co-based superconducting compounds have been found compared with their Fe- or Ni-based counterparts. In this study, we have found superconductivity of 4 K in the LaCoSi compound for the first time. The combined analysis of neutron and synchrotron X-ray powder diffractions reveals that LaCoSi exhibits an isostructure with the known Fe-based LiFeAs superconductor, which is the first "111" Co-based superconductor. First-principles calculation shows that LaCoSi presents a quasi-two-dimensional band structure that is also similar to that of LiFeAs. The small structural distortion may be more conducive to the emergence of superconductivity in the LaCoSi compound, which provides a direction for finding new Co-based superconducting compounds.

Strong Room-Temperature Ferroelectricity in Strained SrTiO3 Homoepitaxial Film

Although the discovery of exceptional ferroelectricity in paraelectrics offers great opportunities to enrich the diversity of the ferroelectric family and promote the development of novel functionalities, transformation of paraelectric phases into ferroelectric phases remains challenging. Herein, a method is presented for driving paraelectrics into ferroelectric states via the introduction of M/O-deficient (M for metal) perovskite nanoregions. Using this method, strong ferroelectricity, equivalent to that of classic ferroelectrics, is achieved in a prototype paraelectric strontium titanate (SrTiO₃ ) homoepitaxial film embedded with Ti/O-deficient perovskite nanoregions. It is shown that these unique nanoregions impose large out-of-plane tensile strain and electron-doping effects on the matrix to form a tetragonal structure (tetragonality = 1.038), driving the off-center movements of Ti and Sr atoms. This leads to a significant room-temperature ferroelectric polarization (maximum polarization = 41.6 µC cm^-2 and spontaneous polarization = 25.2 µC cm^-2 at 1.60 MV cm^-1 ) with a high thermal stability (T_stable  ≈ 1098 K). The proposed approach can be applied to various paraelectrics for creating ferroelectricity and generating emergent physical properties, opening the door to a new realm of materials design.

MiR-22-3p regulates the proliferation and invasion of Wilms' tumor cells by targeting AKT3

OBJECTIVE

In this study, the regulatory mechanism of miR-22-3p/AKT3 in the development of Wilms' tumor (WT) was investigated.

PATIENTS AND METHODS

Twenty-seven pairs of surgical tumor specimens and adjacent normal tissues were obtained from Jining No. 1 People's Hospital. The expression level of miR-22-3p in WT tissues and cell lines was measured by quantitative RT-PCR. MTT and transwell assays were performed to analyze cell proliferation and invasion in WT. The relationship between miR-22-3p and AKT3 was verified by a Dual-Luciferase assay. The protein expression of AKT3 was evaluated by Western blotting analysis.

RESULTS

MiR-22-3p was downregulated and AKT3 was upregulated in WT. Functionally, overexpression of miR-22-3p inhibited cell proliferation and invasion in WT. Moreover, miR-22-3p directly targets AKT3. The knockdown of AKT3 suppressed cell proliferation and invasion in WT. In addition, upregulation of AKT3 restored the tumor suppressive effect of miR-22-3p in WT.

CONCLUSIONS

MiR-22-3p inhibits the proliferation and invasion of WT cells by downregulating AKT3, indicating that miR-22-3p may be developed as a new biomarker for the diagnosis of WT.

Iron deficiency plays essential roles in the trigger, treatment, and prognosis of autosomal dominant hypophosphatemic rickets

By analyzing iron status of 14 ADHR patients, we found that iron deficiency was an important trigger of ADHR. Correcting iron deficiency significantly improved patients' symptoms. Meanwhile, patients' serum phosphate showed positive correlations with iron metabolism parameters and hemoglobin-related parameters, suggesting the necessity of monitoring and correcting the iron status in ADHR.

INTRODUCTION

Autosomal dominant hypophosphatemic rickets (ADHR) is unique for its incomplete penetrance, variety of disease onsets, and waxing and waning phenotypes. Iron deficiency is a trigger of ADHR. This study aimed to clarify the role of iron deficiency in ADHR.

METHODS

Data of clinical manifestations and laboratory examinations were collected from patients among eight kindreds with ADHR. Multiple regression and Pearson's correlation tests were performed to test the relationships of serum phosphate levels and other laboratory variables during the patients' follow-ups.

RESULTS

Among 23 ADHR patients with fibroblast growth factor 23 (FGF23) mutations, 14 patients presented with obvious symptoms. Ten patients had iron deficiency at the onset of ADHR, coinciding with menarche, menorrhagia, pregnancy, and chronic gastrointestinal bleeding. Two patients who did not have their iron status tested presented with symptoms after abortion and pregnancy in one patient each, which suggested that they also had iron deficiency at onset. Patients were treated with ferrous succinate tablets, vitamin C, and neutral phosphate and calcitriol. With correction of the iron status, the patients' symptoms showed notable improvement, with increased serum phosphate levels. Two patients' FGF23 levels also declined to the normal range. There were strong correlations between serum phosphate and serum iron levels (r = 0.7689, p < 0.0001), serum ferritin levels (r = 0.5312, p = 0.002), iron saturation (r = 0.7907, p < 0.0001), and transferrin saturation (r = 0.7875, p < 0.001). We also examined the relationships between serum phosphate levels and hemoglobin-related indices, which were significant (hemoglobin: r = 0.71, p < 0.0001; MCV: r = 0.7589, p < 0.0001; MCH: r = 0.8218, p < 0.0001; and MCHC: r = 0.7751, p < 0.0001). Longitudinal data of six patients' follow-up also showed synchronous changes in serum phosphate with serum iron levels.

CONCLUSIONS

Iron deficiency plays an important role in triggering ADHR. Monitoring and correcting the iron status are helpful for diagnosing and treating ADHR. Iron metabolism parameters and hemoglobin-related parameters are positively correlated with serum phosphate levels in patients with ADHR and iron deficiency, and these might serve as good indicators of prognosis of ADHR.

[Effects of neuromuscular exercise therapy on the joint stability of patients with knee osteoarthritis]

Objective: To evaluate the effects of neuromuscular exercise therapy on joint stability of knee osteoarthritis (OA) patients. Methods: One hundred and ten patients with knee OA were enrolled in this ongoing prospective cohort study at Arthritis Clinic and Research Center, Peking University People's Hospital from September 2017 to October 2018. The treatment consisted of six-week neuromuscular exercise therapy. The participants were followed up at 6 weeks and 3 months after the therapy. The stability of the joint was evaluated by the index of knee joint stability (IKJS), which was extracted by a novel knee-aiming task combined with the multiscale entropy (MSE) analysis of the complexity of the light spot trajectories. The secondary outcomes were pain on the visual analogue scale (VAS, 0-100), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), quality of life on the Euro-quality of life-5 Dimensional (EQ-5D) VAS form, 30-second chair stand test and 40-meter walk test. One-way repeated measures ANOVA analysis was applied to compare the outcomes at baseline and 6 weeks and 3 months. Pearson partial analysis was used to investigate the correlation between the IKJS and the Kellgren-Lawrence (K/L) rate, pain and knee function. Results: Ninety-six participants ((65±8) years, 21 males, 75 females) completed 3-month follow-up. There was a significant improvement in IKJS at the 6-week visit compared with that at baseline (0.369, 95% confidence interval (CI) 0.241-0.496, P<0.001). The IKJS dropped at 3-month visit compared with 6-week visit, but was still better than that at baseline (0.178, 95%CI: 0.042-0.314, P=0.008). The correlation between IKJS and K/L rate, severity of pain, WOMAC or knee function was not significant (r=-0.131, -0.059, -0.231, 0.124, all P>0.05). There was improvement in pain VAS, WOMAC, EQ-5D-VAS, 30-second chair stand test and 40-meter walk test at 6 weeks and 3 months (all P<0.05). Conclusion: The neuromuscular exercise therapy is effective in improving the joint stability of the knee OA patients. However, the effect gradually diminished over time. In addition, neuromuscular exercise can help relieve pain, improve the function and quality of life in patients with knee OA.

Enhanced ferroelectricity in NaNbO3–LaCoO3:Mn epitaxial thin film

A (001)-oriented NaNbO3–LaCoO3:Mn ferroelectric thin film with enhanced tetragonal distortion and large remanent polarization (31 μC cm−2) achieved by chemical modification was successfully deposited on a SrRuO3-buffered LaAlO3 substrate.

In situ determination of the interplay of the structure and domain under a subcoercive field in BiScO3–PbTiO3

The existence of bridging domains in the vicinity of morphotropic phase boundaries brings an insight into the interplay of phase and domain and explains the excellent piezoelectric performance.