Phase transitions associated with magnetic-field induced topological orbital momenta in a non-collinear antiferromagnet.

Resistivity measurements are widely exploited to uncover electronic excitations and phase transitions in metallic solids. While single crystals are preferably studied to explore crystalline anisotropies, these usually cancel out in polycrystalline materials. Here we show that in polycrystalline Mn3Zn0.5Ge0.5N with non-collinear antiferromagnetic order, changes in the diagonal and, rather unexpected, off-diagonal components of the resistivity tensor occur at low temperatures indicating subtle transitions between magnetic phases of different symmetry. This is supported by neutron scattering and explained within a phenomenological model which suggests that the phase transitions in magnetic field are associated with field induced topological orbital momenta. The fact that we observe transitions between spin phases in a polycrystal, where effects of crystalline anisotropy are cancelled suggests that they are only controlled by exchange interactions. The observation of an off-diagonal resistivity extends the possibilities for realising antiferromagnetic spintronics with polycrystalline materials.

Study of Low-Pressure Cold Spray Additive Manufacturing: Investigation of Kinematic Spray Parameters on Deposition and Properties.

Low-pressure cold spray (LPCS) has broadened the application field of cold spray owing to its portability and low cost. For additive manufacturing (AM) based on LPCS (LPCSAM), it is important to investigate the effects of parameters such as temperature and pressure of the gas, stand-off distance, gun traverse speed, and the number of scanning passes of the gun on the deposition and properties. This study aims to determine the optimal kinematic spray parameters for spraying Cu+Al2O3 powder onto an aluminum substrate through LPCS, so as to prepare for the next AM work. The deposition mass, deposition rate, microhardness, and roughness under different spraying conditions were studied. The best spraying effect, with a high deposition rate and without nozzle clogging, was obtained at a nitrogen pressure of 0.9 MPa and a temperature of 400°C.

A Rationally Designed CRISPR/Cas12a Assay Using a Multimodal Reporter for Various Readouts.

The CRISPR/Cas systems offer a programmable platform for nucleic acid detection, and CRISPR/Cas-based diagnostics (CRISPR-Dx) have demonstrated the ability to target nucleic acids with greater accuracy and flexibility. However, due to the configuration of the reporter and the underlying labeling mechanism, almost all reported CRISPR-Dx rely on a single-option readout, resulting in limitations in end-point result readouts. This is also associated with high reagent consumption and delays in diagnostic reports due to protocol differences. Herein, we report for the first time a rationally designed Cas12a-based multimodal universal reporter (CAMURE) with improved sensitivity that harnesses a dual-mode reporting system, facilitating options in end-point readouts. Through systematic configurations and optimizations, our novel universal reporter achieved a 10-fold sensitivity enhancement compared to the DETECTR reporter. Our unique and versatile reporter could be paired with various readouts, conveying the same diagnostic results. We applied our novel reporter for the detection of staphylococcal enterotoxin A due to its high implication in staphylococcal food poisoning. Integrated with loop-mediated isothermal amplification, our multimodal reporter achieved 10 CFU/mL sensitivity and excellent specificity using a real-time fluorimeter, in-tube fluorescence, and lateral flow strip readouts. We also propose, using artificially contaminated milk samples, a fast (2-5 min) Triton X-100 DNA extraction approach with a comparable yield to the commercial extraction kit. Our CAMURE could be leveraged to detect all gene-encoding SEs by simply reprogramming the guide RNA and could also be applied to the detection of other infections and disease biomarkers.

Mixed electronic and oxide ionic conduction and migration mechanisms in digermanate La2-xCaxGe2O7-x/2.

Mixed electronic and oxide ionic conduction was enabled in digermanate-type La2-xCaxGe2O7-x/2 containing Ge3O10 chains and isolated GeO4 units by substitution of La3+ with Ca2+. The structure and solid solution limit of Ca doped La2Ge2O7 were studied by systematic experiments, including rotation electron diffraction (RED), X-ray diffraction (XRD) and neutron powder diffraction (NPD) experiments, etc. The preferred occupation of Ca2+ and oxygen vacancies was investigated by Rietveld analysis of the NPD data. The obtained conducting material La1.925Ca0.075Ge2O6.963 exhibits superior thermal stability and an order of magnitude improvement in conductivity compared to the parent La2Ge2O7 (∼9 × 10-5 S cm-1 at 1000 °C). BVEL calculations reveal that the oxygen vacancies were stabilized and transported within the framework of La2Ge2O7 by sharing oxygen and oxygen exchange between the adjacent Ge3O10 chains and GeO4 units, exhibiting a three-dimensional oxide ion transport nature.

Lightweight Helmet Detection Algorithm Using an Improved YOLOv4.

Safety helmet wearing plays a major role in protecting the safety of workers in industry and construction, so a real-time helmet wearing detection technology is very necessary. This paper proposes an improved YOLOv4 algorithm to achieve real-time and efficient safety helmet wearing detection. The improved YOLOv4 algorithm adopts a lightweight network PP-LCNet as the backbone network and uses deepwise separable convolution to decrease the model parameters. Besides, the coordinate attention mechanism module is embedded in the three output feature layers of the backbone network to enhance the feature information, and an improved feature fusion structure is designed to fuse the target information. In terms of the loss function, we use a new SIoU loss function that fuses directional information to increase detection precision. The experimental findings demonstrate that the improved YOLOv4 algorithm achieves an accuracy of 92.98%, a model size of 41.88 M, and a detection speed of 43.23 pictures/s. Compared with the original YOLOv4, the accuracy increases by 0.52%, the model size decreases by about 83%, and the detection speed increases by 88%. Compared with other existing methods, it performs better in terms of precision and speed.

Harnessing enhanced CRISPR/Cas12a trans-cleavage activity with extended reporters and reductants for early diagnosis of Helicobacter pylori, the causative agent of peptic ulcers and stomach cancer.

Developing rapid and non-invasive diagnostics for Helicobacter pylori (HP) is imperative to prevent associated diseases such as stomach gastritis, ulcers, and cancers. Owing to HP strain heterogeneity, not all HP-infected individuals incur side effects. Cytotoxin-associated gene A (CagA), and vacuolating cytotoxin A (VacA) genes predominantly drive HP pathogenicity. Therefore, diagnosing CagA and VacA genotypes could alert active infection and decide suitable therapeutics. We report an enhanced LbCas12a trans-cleavage activity with extended reporters and reductants (CEXTRAR) for early detection of HP. We demonstrate that extended ssDNA reporter acts as an excellent signal amplifier, making it a potential alternative substrate for LbCas12a collateral activity. Through a systematic investigation of various buffer components, we demonstrate that reductants improve LbCas12a trans-cleavage activity. Overall, our novel reporter and optimal buffer increased the trans-cleavage activity to an order of 16-fold, achieving picomolar sensitivity (171 pM) without target pre-amplification. Integrated with loop-mediated isothermal amplification (LAMP), CEXTRAR successfully attained attomolar sensitivity for HP detection using real-time fluorescence (43 and 96 aM), in-tube fluorescence readouts (430 and 960 aM), and lateral flow (4.3 and 9.6 aM) for CagA and VacA, respectively. We also demonstrate a rapid 2-min Triton X-100 lysis for clinical sample analysis, which could provide clinicians with actionable information for rapid diagnosis. CEXTRAR could potentially spot the 13C urea breath test false-negatives. For the first time, our study unveils an experimental outlook to manipulate reporters and reconsider precise cysteine substitution via protein engineering for Cas variants with enhanced catalytic activities for use in diagnostics and genetic engineering.

MicroRNA-206 down-regulated human umbilical cord mesenchymal stem cells alleviate cognitive decline in D-galactose-induced aging mice.

BACKGROUND: Non-pathological cognitive decline is a neurodegenerative condition associated with brain aging owing to epigenetic changes, telomere shortening, stem cells exhaustion, or altered differentiation. Human umbilical cord mesenchymal stem cells (hUCMSCs) have shown excellent therapeutic prospects on the hallmarks of aging. In this study, we aimed to elucidate the role of hUCMSCs with down-regulated miRNA-206 (hUCMSCs anti-miR-206) on cognitive decline and the underlying mechanism. METHODS: After daily subcutaneous injection of D-gal (500 mg/kg/d) for 8 weeks, 17-week-old male C57BL/6 J mice were stem cells transplanted by lateral ventricular localization injection. During the 10-day rest period, were tested the behavioral experiments applied to cognitive behavior in the hippocampus. And then, the mice were sacrificed for sampling to complete the molecular and morphological experiments. RESULTS: Our behavioral experiments of open field test (OFT), new object recognition test (NOR), and Y-maze revealed that D-galactose (D-gal)-induced aging mice treated with hUCMSCs anti-miR-206 had no obvious spontaneous activity disorder and had recovery in learning and spatial memory ability compared with the PBS-treated group. The hUCMSCs anti-miR-206 reconstituted neuronal physiological function in the hippocampal regions of the aging mice with an increase of Nissl bodies and the overexpression of Egr-1, BDNF, and PSD-95. CONCLUSION: This study first reports that hUCMSCs anti-miR-206 could provide a novel stem cell-based antiaging therapeutic approach.

Transcription factor EB-mediated mesenchymal stem cell therapy induces autophagy and alleviates spinocerebellar ataxia type 3 defects in neuronal cells model.

Defects in ataxin-3 proteins and CAG repeat expansions in its coding gene ATXN3 cause Spinocerebellar Ataxia Type 3 (SCA3) or Machado-Joseph disease (MJD) polyglutamine neurodegenerative disease. The mutant proteins aggregate as inclusion bodies in cells and compete with wild-type ataxin-3, which leads to neuronal dysfunction or death and impairs Beclin1-mediated autophagy. It has been reported that Mesenchymal stem cells (MSCs) can reliably treat several neurodegenerative diseases. Herein, we used a Transcription Factor EB (TFEB) nuclear translocation-mediated MSCs co-culture approach to reconstitute autophagy and lysosomal biogenesis, and reduce SCA3-like behaviors in induced pluripotent stem cells (iPSCs)-derived neuron cells models. Our iPSCs model showed enhanced expression of autophagy proteins, attenuated the expression and toxic effects of mutant ataxin-3 on neurons, and alleviated the effects of ataxin-3 on autophagy. Therefore, MSCs are associated with autophagy-inducing therapy and compared to animal models, our MSCs co-culture could be used as a novel and potential therapeutic approach to study SCA3 disease and other neurodegenerative diseases.

RuO2 electronic structure and lattice strain dual engineering for enhanced acidic oxygen evolution reaction performance.

Developing highly active and durable electrocatalysts for acidic oxygen evolution reaction remains a great challenge due to the sluggish kinetics of the four-electron transfer reaction and severe catalyst dissolution. Here we report an electrochemical lithium intercalation method to improve both the activity and stability of RuO2 for acidic oxygen evolution reaction. The lithium intercalates into the lattice interstices of RuO2, donates electrons and distorts the local structure. Therefore, the Ru valence state is lowered with formation of stable Li-O-Ru local structure, and the Ru-O covalency is weakened, which suppresses the dissolution of Ru, resulting in greatly enhanced durability. Meanwhile, the inherent lattice strain results in the surface structural distortion of LixRuO2 and activates the dangling O atom near the Ru active site as a proton acceptor, which stabilizes the OOH* and dramatically enhances the activity. This work provides an effective strategy to develop highly efficient catalyst towards water splitting.

Neutron powder-diffraction study of phase transitions in strontium-doped bismuth ferrite: 1. Variation with chemical composition.

We report results from a study of the crystal and magnetic structures of strontium-doped BiFeO3using neutron powder diffraction and the Rietveld method. Measurements were obtained over a wide range of temperatures from 300-800 K for compositions between 10%-16% replacement of bismuth by strontium. The results show a clear variation of the two main structural deformations-symmetry-breaking rotations of the FeO6octahedra and polar ionic displacements that give ferroelectricity-with chemical composition, but relatively little variation with temperature. On the other hand, the antiferromagnetic order shows a variation with temperature and a second-order phase transition consistent with the classical Heisenberg model. There is, however, very little variation in the behaviour of the antiferromagnetism with chemical composition, and hence with the degree of the structural symmetry-breaking distortions. We therefore conclude that there is no significant coupling between antiferromagnetism and ferroelectricity in Sr-doped BiFeO3and, by extension, in pure BiFeO3.

Application of Image Segmentation to Identify In-flight Particles in Thermal Spraying.

In thermal spray process, the characteristics of in-flight particles (velocity and temperature) play an important role regarding the microstructure of the deposit and thus the coating performances. The implementation of diagnostic devices is necessary to measure such characteristics. Many imaging systems and algorithms have been developed for identifying and tracking in-flight particles. However, these current image systems have significant limitations in terms of accuracy for example. One key to solving the tracking problem is to get an algorithm that can effectively distinguish different particles in the same image frame at the same time. This study aims to develop an algorithm capable of identifying a large number of in-flight particles sprayed by thermal process. The results show that the noise and vignettes could be successfully treated, particles are clearly recognized in the background, leading to properly measuring the sizes and positions of the particle versus time. The proposed algorithm has a higher recognition rate and recognition range than other algorithms, which will provide a reasonable basis for subsequent calculation and processing.

Structure elucidation, biogenesis, and bioactivities of acylphloroglucinol-derived meroterpenoid enantiomers from Dryopteris crassirhizoma.

Twenty-four racemic acylphloroglucinol meroterpenoids including eighteen unusual stuctures (3 âˆ¼ 10, 13, 14, and 17 âˆ¼ 24), and a major component filixic acid ABA (25), were isolated from Dryopteris crassirhizoma. Structurally, the dimeric acylphloroglucinol derivatives possess unprecedented skeletons of mixed acylphloroglucinol and sesquiterpene biosynthetic origin. The stereochemistries of six reported meroterpenoids with undefined chiral centers were reassigned. Two intriguing methods by analyzing a) the regularity of chemical shift variation of protons and carbons around the stereogenic centers, and b) pyridine-induced deshielding effect of hydroxy groups, to discriminate relative configurations of flexible long-chain alcohol with chiral centers separated by three or seven covalent bonds, were successfully applied. A non-enzymatic biosynthesis of 1 âˆ¼ 24 was assumed based on a rare single-crystal cluster formed with two diastereomeric enantiomer pairs (±1/±2) and chiral HPLC analyses. Meroterpenoids 13 and 14 showed obvious inhibitory effects on NO production in LPS-induced RAW264.7, and suppressed the expression of iNOS, COX-2, IL-1ß, and IL-18. Their anti-inflammatory activity was closely related to the inhibition of the formation and function of inflammasomes. Additionally, the known 25 showed antiviral efficacy against the influenza viruse A/Puerto Rico/8/1934 (H1N1).

Hair follicle-derived mesenchymal stem cells decrease alopecia areata mouse hair loss and reduce inflammation around the hair follicle.

BACKGROUND: Alopecia areata (AA) is a common autoimmune hair loss disease with increasing incidence. Corticosteroids are the most widely used for hair loss treatment; however, long-term usage of hormonal drugs is associated with various side effects. Mesenchymal stem cells (MSCs) therapy has been studied extensively to curb autoimmune diseases without affecting immunity against diseases. METHODS: Hair follicle-derived MSCs (HF-MSCs) were harvested from the waste material of hair transplants, isolated and expanded. The therapeutic effect of HF-MSCs for AA treatment was investigated in vitro AA-like hair follicle organ model and in vivo C3H/HeJ AA mice model. RESULTS: AA-like hair follicle organ in vitro model was successfully established by pre-treatment of mouse vibrissa follicles by interferon-γ (IFN-γ). The AA-like symptoms were relieved when IFN-γ induced AA in vitro model was co-cultured with HF-MSC for 2 days. In addition, when skin grafted C3H/HeJ AA mice models were injected with 106 HF-MSCs once a week for 3 weeks, the transcription profiling and immunofluorescence analysis depicted that HF-MSCs treatment significantly decreased mouse hair loss and reduced inflammation around HF both in vitro and in vivo. CONCLUSIONS: This study provides a new therapeutic approach for alopecia areata based on HF-MSCs toward its future clinical application.

S100A4 plays a key role in TRPV3 ion channel expression and its electrophysiological function.

Transient receptor potential vanilloid 3 (TRPV3), a non-selective cation ion channel, is regulated by small molecules such as Ca2+ and calmodulin (CaM). Together with S100A4 (S100 calcium-binding protein family), is critical in cell proliferation and progression. Although TRPV3 has been proved to play a role in Ca2+ regulation and participate in Ca2+-related cellular processes, its molecular mechanism remains unclear. In this study, we found that TRPV3 and S100A4 were co-expressed in the same region of the cell, and surprisingly, the protein expression level of TRPV3 significantly increased with the overexpression of S100A4. Moreover, co-immunoprecipitation results showed that these two proteins could bind with each other. Functionally, we found that when S100A4 was simultaneously expressed in cells, more Ca2+ would be transferred into the cells through the TRPV3 ion channel. Consistent with Ca2+ regulation results, electrophysiological recordings demonstrated that S100A4 improved the function of TRPV3 in ions' flux, suggesting that the S100A4 could bind with TRPV3 and simultaneously promoted its expression, thus affecting its functions on related ions' flux. Our findings identified the link between S100A4 and TRPV3 and provided a novel molecular mechanism for TRPV3 regulation.

A Distinct Spin Structure and Giant Baromagnetic Effect in MnNiGe Compounds with Fe-Doping.

Spin structure of a magnetic system results from the competition of various exchange couplings. Pressure-driven spin structure evolution, through altering interatomic distance, and hence, electronic structure produces baromagnetic effect (BME), which has potential applications in sensor/actuator field. Here, we report a new spin structure(CyS-AFMb) with antiferromagnetic(AFM) nature in Fe-doped Mn0.87Fe0.13NiGe. Neutron powder diffraction (NPD) under in situ hydrostatic pressure and magnetic field was conducted to reveal the spin configuration and its instabilities. We discovered that a pressure higher than 4 kbar can induce abnormal change of Mn(Fe)-Mn(Fe) distances and transform the CyS-AFMb into a conical spiral ferromagnetic(FM) configuration(45°-CoS-FMa) with easily magnetized but shortened magnetic moment by as much as 22%. The observed BME far exceeds previous reports. Our first-principles calculations provide theoretical supports for the enhanced BME. The compressed lattice by pressure favors the 45°-CoS-FMa and significantly broadened 3d bandwidth of Mn(Fe) atoms, which leads to the shortened magnetic moment and evolution of spin structure.

A heterozygous SCN1A (c.A5768G/+) mutant human induced pluripotent stem cell line (USTCi002-A) generated using TALEN-mediated precise gene editing.

Severe mycological epilepsy of infancy is a catastrophic disease with preferential dysfunction of interneurons, frequentepisoderate, cognitive and sudden death. The disease is mainly caused by heterozygous loss-of-function mutation of SCN1A gene encoding α subunit of the sodium channel Nav1.1. To generate mutations in normal iPSC, Transcription activator-like effector nucleases was used to introduce the epilepsy-causing mutation A5768G into the endogenous locus of SCN1A gene. The gene editing induced pluripotent stem cell line and normal iPSC were obtained from the same donor to eliminate significantly the genetic background noise.

Generation of a tdTomato-GAD67 reporter human epilepsia mutation induced pluripotent stem cell line, USTCi001-A-2, using CRISPR/Cas9 editing.

Dravet syndrome is an epileptic encephalopathy largely due to haploinsufficiency of the voltage-gated sodium channel Nav1.1 that is expressed primarily in GABAergic neurons. In order to distinguish the different subtypes, we used gene editing to introduce tdTomato gene into the genome of iPSCs to label the GABAergic neurons in the differentiated neuronal networks. The gene-edited cell line demonstrates normal karyotype, expresses the main pluripotency markers, and shows the presence of differentiation into the three embryonic germ layers in teratomas.

Transient receptor potential ankyrin 1 contributes to the ATP-elicited oxidative stress and inflammation in THP-1-derived macrophage.

P2X7 receptor (P2X7R) is an ATP-gated non-selective cation channel which mediates ATP-induced inflammation in macrophages. Transient receptor potential (TRP) receptors are nociceptors in cellular membrane which can perceive the stimuli of environmental irritant. The interaction between TRP channels and P2X7R has been found while the details about inflammation are still unclear. In this study, we suggested that transient receptor potential ankyrin 1 (TRPA1), a member of TRP superfamily, participates in ATP-induced oxidative stress and inflammation in human acute monocytic leukemia cell line (THP-1)-derived macrophage. The co-localization between TRPA1 and P2X7R was detected using immunofluorescence in THP-1-derived macrophage and transfected human embryonic kidney cell line (HEK293T). The mechanism by which ATP or 3'-O-(4-Benzoylbenzoyl)-ATP (BzATP) induces the activation of macrophages was verified by calcium imaging, mitochondrial reactive oxygen species (mtROS) detection, mitochondrial membrane potential (∆Ψm) measurement, flow cytometry, enzyme-linked immunosorbent assay (ELISA), western blotting, CCK-8 assay, and the lactate dehydrogenase (LDH) release cytotoxic assay. The BzATP and ATP induced calcium overload, mitochondria injury, interleukin-1ß (IL-1ß) secretion, and cytotoxicity can be inhibited by TRPA1 antagonists. These results indicated that TRPA1 can co-localize with P2X7R and mediate ATP-induced oxidative stress and inflammation. Therefore, the inhibition of TRPA1 may provide a potential therapy for ATP-elicited inflammatory diseases, including atherosclerosis.

Room Temperature Zero Thermal Expansion in a Cubic Cobaltite.

Zero thermal expansion (ZTE) materials are highly desired in modern industries where high-precision processing is necessary. However, ZTE materials in pure form are extremely rare. The most widely used are Invar alloys, where the ZTE is intimately associated with spontaneous magnetic ordering, known as the magnetovolume effect (MVE). Despite tremendous studies, there is still no consensus on the microscopic origin of MVE in Invar alloys. Here, we report the discovery of room-temperature isotropic ZTE in a pure-form cobaltite perovskite, A-site disordered La0.5Ba0.5CoO3-x. The temperature window of the anomalous thermal expansion shows large tunability by simply altering the oxygen content, making this material a promising candidate for practical applications. Furthermore, we unveil with compelling experimental evidence that the ZTE originates from an isostructural transition between antiferromagnetic large-volume phase and ferromagnetic small-volume phase, which might shed light on the MVE in Invar alloys.