Reconciling Monolayer and Bilayer J_{eff}=1/2 Square Lattices in Hybrid Oxide Superlattice.

The number of atomic layers confined in a two-dimensional structure is crucial for the electronic and magnetic properties. Single-layer and bilayer J_{eff}=1/2 square lattices are well-known examples where the presence of the extra layer turns the XY anisotropy to the c-axis anisotropy. We report on experimental realization of a hybrid SrIrO_{3}/SrTiO_{3} superlattice that integrates monolayer and bilayer square lattices in one layered structure. By synchrotron x-ray diffraction, resonant x-ray magnetic scattering, magnetization, and resistivity measurements, we found that the hybrid superlattice exhibits properties that are distinct from both the single-layer and bilayer systems and cannot be explained by a simple addition of them. In particular, the entire hybrid superlattice orders simultaneously through a single antiferromagnetic transition at temperatures similar to the bilayer system but with all the J_{eff}=1/2 moments mainly pointing in the ab plane similar to the single-layer system. The results show that bringing monolayer and bilayer with orthogonal properties in proximity to each other in a hybrid superlattice structure is a powerful way to stabilize a unique state not obtainable in a uniform structure.

ERK1/2 mitogen-activated protein kinase mediates downregulation of intestinal tight junction proteins in heat stress-induced IBD model in pig.

In many mammalian species, including pigs, heat stress (HS) detrimentally leads to epithelium damage and increases intestinal permeability. However, the underlying molecular mechanisms are not thoroughly investigated yet. This study aimed to examine the RIP1/RIP3-ERK1/2 signaling pathway that regulates the expression of tight junction proteins in HS-treated pigs. In in vitro cultured intestinal porcine epithelial cells (IPEC-J2), HS induced the expression of tight junction proteins, ZO-1, claudin-1, and claudin-4, that are regulated by the ERK1/2-MAPK signaling pathway. Further, high expression of HSP70 in IPEC-J2 cells induced a significant decrease in receptor-interacting protein 1/3 (RIP1/3), phosphorylated ERK, and tight junction protein claudin-1 (P < 0.05). Necrostatin-1 (A selective inhibitor of RIPK1) suppressed the upregulation of phosphorylated ERK1/2 induced by HS, indicating that the RIP1/RIP3 regulates ERK1/2 phosphorylation in IPEC-J2 under heat stress. In addition, HS significantly damaged the intestinal morphology characterized by reduction of villus length and crypt depth in in vivo porcine model. Moreover, the expression of tight junction, ZO-1, and claudin-4 were downregulated, whereas phosphorylated p38 and ERK1/2 were upregulated in the duodenum of heat-stressed pigs. Interestingly, a decrease in ZO-1 and claudin-1 was observed in the colon, where phosphorylated ERK1/2 was similar to that in the duodenum. Our results demonstrate that RIP1/RIP3-ERK1/2 signaling pathway regulates the expression of tight junction proteins in HS-pigs. This finding further advances the intestinal barrier function's underlying mechanisms associated with signaling regulation.

Unconventional Antiferromagnetic Quantum Critical Point in Ba(Fe_{0.97}Cr_{0.03})_{2}(As_{1-x}P_{x})_{2}.

We have systematically studied physical properties of Ba(Fe_{0.97}Cr_{0.03})_{2}(As_{1-x}P_{x})_{2}, where superconductivity in BaFe_{2}(As_{1-x}P_{x})_{2} is fully suppressed by just 3% of Cr substitution of Fe. A quantum critical point is revealed at x∼0.42, where non-Fermi-liquid behaviors similar to those in BaFe_{2}(As_{1-x}P_{x})_{2} are observed. Neutron diffraction and inelastic neutron scattering measurements suggest that the quantum critical point is associated with the antiferromagnetic order, which is not of conventional spin-density-wave type as evidenced by the ω/T scaling of spin excitations. On the other hand, no divergence of low-temperature nematic susceptibility is observed when x is decreased to 0.42 from higher doping level, demonstrating that there are no nematic quantum critical fluctuations. Our results suggest that non-Fermi-liquid behaviors in iron-based superconductors can be solely resulted from the antiferromagnetic quantum critical fluctuations, which cast doubts on the role of nematic fluctuations played in the normal-state properties in iron-based superconductors.

Odd and Even Modes of Neutron Spin Resonance in the Bilayer Iron-Based Superconductor CaKFe_{4}As_{4}.

We report an inelastic neutron scattering study on the spin resonance in the bilayer iron-based superconductor CaKFe_{4}As_{4}. In contrast to its quasi-two-dimensional electron structure, three strongly L-dependent modes of spin resonance are found below T_{c}=35 K. The mode energies are below and linearly scale with the total superconducting gaps summed on the nesting hole and electron pockets, essentially in agreement with the results in cuprate and heavy fermion superconductors. This observation supports the sign-reversed Cooper pairing mechanism under multiple pairing channels and resolves the long-standing puzzles concerning the broadening and dispersive spin resonance peak in iron pnictides. More importantly, the triple resonant modes can be classified into odd and even symmetries with respect to the distance of Fe-Fe planes within the Fe-As bilayer unit. Thus, our results closely resemble those in the bilayer cuprates with nondegenerate spin excitations, suggesting that these two high-T_{c} superconducting families share a common nature.

Neutron Spin Resonance in the 112-Type Iron-Based Superconductor.

We use inelastic neutron scattering to study the low-energy spin excitations of the 112-type iron pnictide Ca_{0.82}La_{0.18}Fe_{0.96}Ni_{0.04}As_{2} with bulk superconductivity below T_{c}=22 K. A two-dimensional spin resonance mode is found around E=11 meV, where the resonance energy is almost temperature independent and linearly scales with T_{c} along with other iron-based superconductors. Polarized neutron analysis reveals the resonance is nearly isotropic in spin space without any L modulations. Because of the unique monoclinic structure with additional zigzag arsenic chains, the As 4p orbitals contribute to a three-dimensional hole pocket around the Γ point and an extra electron pocket at the X point. Our results suggest that the energy and momentum distribution of the spin resonance does not directly respond to the k_{z} dependence of the fermiology, and the spin resonance intrinsically is a spin-1 mode from singlet-triplet excitations of the Cooper pairs in the case of weak spin-orbital coupling.

Unified Phase Diagram for Iron-Based Superconductors.

High-temperature superconductivity is closely adjacent to a long-range antiferromagnet, which is called a parent compound. In cuprates, all parent compounds are alike and carrier doping leads to superconductivity, so a unified phase diagram can be drawn. However, the properties of parent compounds for iron-based superconductors show significant diversity and both carrier and isovalent dopings can cause superconductivity, which casts doubt on the idea that there exists a unified phase diagram for them. Here we show that the ordered moments in a variety of iron pnictides are inversely proportional to the effective Curie constants of their nematic susceptibility. This unexpected scaling behavior suggests that the magnetic ground states of iron pnictides can be achieved by tuning the strength of nematic fluctuations. Therefore, a unified phase diagram can be established where superconductivity emerges from a hypothetical parent compound with a large ordered moment but weak nematic fluctuations, which suggests that iron-based superconductors are strongly correlated electron systems.

Histopathological changes in zebrafish embryos exposed to DLPCBs extract from Zhanjiang coastal sediment.

Dioxin-like polychlorinated biphenyls (DLPCBs) are ubiquitous persistent pollutants that cause adverse effects in many environmental organisms. DLPCBs in marine sediments can be absorbed by benthic organisms, bioaccumulate, and biomagnify through the food chain and threaten animal and human health. There are no reports of DLPCBs concentrations in the Zhanjiang Gulf seabed. This study was designed to investigate the concentration of DLPCBs in the Zhanjiang coastal sediment and histopathological changes in zebrafish (Diano rerio) embryos exposed to environmentally relevant concentrations of DLPCBs. Of the five sites selected, two sites TS and JSW contained DLPCBs at concentrations of 0.08 and 22.54 ng/g dry sediment, respectively. Two groups of zebrafish embryos were used. One group was exposed to 3.75, 7.5, 15, 30, and 60 mg/ml of DLPCBs extracted from the sediments sampled from the TS site and the second group to 4.375, 8.75, 17.5, 35, and 70 mg/ml of DLPCBs from JSW site from 0.75 h post-fertilization (hpf) to 96 hpf. The zebrafish exposed to 60 and 70 mg/ml of DLPCBs at 96 hpf displayed gross histopathological changes with cardiac lesions including pericardial edema being the most deleterious. Other changes observed were hydropic degeneration of gill filaments and hepatocytes, loss of intestinal folds, and uninflated swim bladder. It appears that only a few sites of the Zhanjiang gulf are contaminated with DLPCBs. This is the first report of histopathological changes in the gills, hepatocytes, intestines, heart, and the swim bladder in zebrafish embryos exposed to DLPCBs from a coastal sediment. Further studies with sampling at different stages of development are required to identify which organ/tissue is most sensitive to DLPCBs.

Nematic Quantum Critical Fluctuations in BaFe_{2-x}Ni_{x}As_{2}.

We have systematically studied the nematic fluctuations in the electron-doped iron-based superconductor BaFe_{2-x}Ni_{x}As_{2} by measuring the in-plane resistance change under uniaxial pressure. While the nematic quantum critical point can be identified through the measurements along the (110) direction, as studied previously, quantum and thermal critical fluctuations cannot be distinguished due to similar Curie-Weiss-like behaviors. Here we find that a sizable pressure-dependent resistivity along the (100) direction is present in all doping levels, which is against the simple picture of an Ising-type nematic model. The signal along the (100) direction becomes maximum at optimal doping, suggesting that it is associated with nematic quantum critical fluctuations. Our results indicate that thermal fluctuations from striped antiferromagnetic order dominate the underdoped regime along the (110) direction. We argue that either there is a strong coupling between the quantum critical fluctuations and the fermions, or more exotically, a higher symmetry may be present around optimal doping.

Improved multi-layer wavelet transform and blind source separation based ECG artifacts removal algorithm from the sEMG signal: in the case of upper limbs.

Introduction: Surface electromyogram (sEMG) signals have been widely used in human upper limb force estimation and motion intention recognition. However, the electrocardiogram(ECG) artifact generated by the beating of the heart is a major factor that reduces the quality of the EMG signal when recording the sEMG signal from the muscle close to the heart. sEMG signals contaminated by ECG artifacts are difficult to be understood correctly. The objective of this paper is to effectively remove ECG artifacts from sEMG signals by a novel method. Methods: In this paper, sEMG and ECG signals of the biceps brachii, brachialis, and triceps muscle of the human upper limb will be collected respectively. Firstly, an improved multi-layer wavelet transform algorithm is used to preprocess the raw sEMG signal to remove the background noise and power frequency interference in the raw signal. Then, based on the theory of blind source separation analysis, an improved Fast-ICA algorithm was constructed to separate the denoising signals. Finally, an ECG discrimination algorithm was used to find and eliminate ECG signals in sEMG signals. This method consists of the following steps: 1) Acquisition of raw sEMG and ECG signals; 2) Decoupling the raw sEMG signal; 3) Fast-ICA-based signal component separation; 4) ECG artifact recognition and elimination. Results and discussion: The experimental results show that our method has a good effect on removing ECG artifacts from contaminated EMG signals. It can further improve the quality of EMG signals, which is of great significance for improving the accuracy of force estimation and motion intention recognition tasks. Compared with other state-of-the-art methods, our method can also provide the guiding significance for other biological signals.

[Analysis of the clinical effect of percutaneous pedicle screw fixation combined with transpedicular bone grafting in the treatment of thoracolumbar fracture].

OBJECTIVE: To investigate the clinical efficacy of percutaneous screw fixation combined with minimally invasive transpedicular bone grafting and non-bone grafting in the treatment of thoracolumbar fractures. METHODS: From Janury 2021 to June 2022, 40 patients with thoracolumbar fracture were divided into the experimental group and the control group. There were 26 patients in the experimental group, including 21 males and 5 females with an aberage age of (47.3±12.3) years old, who underwent percutaneous pedicle screw fixation combined with transpedicular autogenous bone grafting. In the control group, 14 patients received percutaneous pedicle screw fixation only. including 7 makes and 7 females with an average age of (50.2±11.2) years old. The operative time, intraoperative blood loss, anterior height ratio of injured vertebrae, Cobb angle, visual analogue score (VAS), MacNab scores, loosening or broken of the implants. were compared and analyzed. RESULTS: There was no significant difference in operation time, intraoperative blood loss, VAS and anterior height ratio of injured vertebrae between the two groups. Compared with the preoperative results, VAS and anterior height ratio of injured vertebrae were improved statistically(P<0.05). For Cobb angle of injured vertebra, there was no significant difference between the two groups before surgery (P=0.766). While at 1 week, 3 months and 12 months after surgery, there were statistically differences between the two groups (P values were 0.042, 0.007 and 0.039, respectively). The Cobb angle of injured vertebrae one year after operation was statistically decreased in both groups compared with that before surgery (P<0.001). One year after surgery, the excellent and good rate of Macnab scores was 96.15% in the experimental group and 92.86% in the control group, and there was no statistical differences between the two groups (P=0.648). There was one patient in the control group suffering superficial wound infection on the third day, which was cured by dressing change and anti-infection treatment. There were no postoperative screw loosening and broken in both groups. CONCLUSION: The two surgical methods have the advantages of less trauma, less pain and quicker recovery, which can restore the height of the injured vertebra, reconstruct the spinal sequence and reduce the fracture of the vertebral body. Transpedicular autogenous bone grafting can increase the stability of the fractured vertebra and maintain the height of the vertebra better after surgery, thus reducing the possibility of complications such as kyphosis, screw loosening and broken.

Tracking the nematicity in cuprate superconductors: a resistivity study under uniaxial pressure.

Overshadowing the superconducting dome in hole-doped cuprates, the pseudogap state is still one of the mysteries that no consensus can be achieved. It has been suggested that the rotational symmetry is broken in this state and may result in a nematic phase transition, whose temperature seems to coincide with the onset temperature of the pseudogap stateT∗around optimal doping level, raising the question whether the pseudogap results from the establishment of the nematic order. Here we report results of resistivity measurements under uniaxial pressure on several hole-doped cuprates, where the normalized slope of the elastoresistivityζcan be obtained as illustrated in iron-based superconductors. The temperature dependence ofζalong particular lattice axis exhibits kink feature atTkand shows Curie-Weiss-like behavior above it, which may suggest a spontaneous nematic transition. WhileTkseems to be the same asT∗around the optimal doping and in the overdoped region, they become very different in underdoped La2-xSrxCuO4. Our results suggest that the nematic order, if indeed existing, is an electronic phase within the pseudogap state.

Heat Stress-Induced Dysbiosis of Porcine Colon Microbiota Plays a Role in Intestinal Damage: A Fecal Microbiota Profile.

The pathological mechanisms of gastrointestinal disorders, including inflammatory bowel disease (IBD), in pigs are poorly understood. We report the induction of intestinal inflammation in heat-stressed (HS) pigs, fecal microbiota transplantation from pigs to mice, and explain the role of microorganisms in IBD. 24 adult pigs were subjected to HS (34 ± 1 °C; 75-85% relative humidity for 24h) while 24 control pigs (CP) were kept at 25 ± 3°C and the same humidity. Pigs were sacrificed on days 1, 7, 14, 21. Colonic content microbiome analyses were conducted. Pseudo-germ-free mice were fed by gavage with fecal microbiota from HS-pigs and CP to induce pig-like responses in mice. From 7 d, HS-pigs exhibited fever and diarrhea, and significantly lower colonic mucosal thickness, crypt depth/width, and goblet cell number. Compared with each control group, the concentration of cortisol in the peripheral blood of HS pigs gradually increased, significantly so on days 7, 14, and 21 (P < 0.01). While the concentration of LPS in HS pigs' peripheral blood was significantly higher on days 7, 14 (P < 0.01), and 21 (P < 0.05) compared with that of the control group. The colonic microbiome composition of HS-pigs was different to that of CP. By day 14, opportunistic pathogens (e.g., Campylobacterales) had increased in HS-pigs. The composition of the colonic microbiome in mice administered feces from HS-pigs was different from those receiving CP feces. Bacteroides were significantly diminished, Akkermansia were significantly increased, and intestinal damage and goblet cell numbers were higher in mice that received HS-pig feces. Moreover, we verified the relevance of differences in the microbiota of the colon among treatments. Heat stress promotes changes in gut microbiome composition, which can affect the colonic microbial structure of mice through fecal microbiota transplantation; the molecular mechanisms require further investigation. This study enhanced our understanding of stress-induced inflammation in the colon and the increase in diarrhea in mammals subjected to prolonged HS. Our results provide useful information for preventing or ameliorating deficits in pig production caused by prolonged exposure to high temperatures.

Clinical outcomes of blood transfusion to patients with pelvic fracture in the initial 6 h from injury.

As part of the treatment of pelvic fracture, major hemorrhage poses a challenge for trauma surgeons. The aim of the present study was to evaluate the clinical outcomes of blood transfusion in the initial 6 h after pelvic fracture, and to define the blood transfusion volume required for each pelvic fracture type. A retrospective cohort study was performed on patients with pelvic fracture at a single Level I Trauma Centre over a 3-year period. A total of 1,297 patients were transported to our trauma centre within 2 h of injury and blood transfusion was administered in the initial 6 h after pelvic fracture. Review of the patients' medical records provided the initial pelvic radiographs and data from emergency department care. Clinical outcomes, including frequency of blood transfusion, blood transfusion volume, injury severity scores and mortality, were evaluated. All pelvic fractures were defined as closed fractures and patients were categorized according to the Arbeit fuer Osteosynthese (AO) classification system. Statistical methods were used to identify trends to provide guidance for clinical prediction. Complete data were available for 497 patients with pelvic fracture, 104 (20.9%) of which received blood transfusion. The blood transfusion volume in the initial 6 h ranged from 0 to 10,000 ml, with a mean of 1,213.94±1354.11 ml. The total mortality rate was 1.8%. Among the patients with C-type pelvic fractures, the frequency of blood transfusion was 59.0% and the mean volume was 2,191.30±1,740.93 ml. The mortality rate for C-type pelvic fractures was 11.43%. The B3 subtype of pelvic fractures had the highest transfusion frequency (53.6%), while the C3 subtype had the largest blood transfusion volume (5,700.00±4,666.90 ml). Patients with type A-C pelvic fractures had a progressively larger mean transfusion volume, transfusion frequency and mortality in the initial 6 h after pelvic fracture. The AO classification system was demonstrated to be a useful tool for the identification of pelvic fracture risk in the present study.

Proteomic analysis of the response of porcine adrenal gland to heat stress.

Heat stress (HS) and its associated pathologies are major challenges facing the pig industry in southern China, and are responsible for large economic losses. However, the molecular mechanisms governing the abnormal secretion of HS-responsive hormones, such as glucocorticoids, are not fully understood. The goal of this study was to investigate differentially expressed proteins (DEPs) in the adrenal glands of pigs, and to elucidate changes in the immune neuroendocrine system in pigs following HS. Through a functional proteomics approach, we identified 1202 peptides, corresponding to 415 proteins. Of these, we found 226 DEPs between heat-stressed and control porcine adrenal gland tissue; 99 of these were up-regulated and 127 were down-regulated in response to HS. These DEPs included proteins involved in substrate transport, cytoskeletal changes, and stress responses. Ingenuity Pathway Analysis was used to identify the subcellular characterization, functional pathway involvement, regulatory networks, and upstream regulators of the identified proteins. Functional network and pathway analyses may provide insights into the complexity and dynamics of HS-host interactions, and may accelerate our understanding of the mechanisms of HS.

Chitosan oligosaccharide-mediated attenuation of LPS-induced inflammation in IPEC-J2 cells is related to the TLR4/NF-κB signaling pathway.

The protective mechanism of chitosan oligosaccharide (COS) against lipopolysaccharides (LPS) -induced inflammatory responses in IPEC-J2 and in mice with DSS dextran sulfate sodium (DSS) -induced colitis is reported. Upon exposure to LPS, the proliferation rate of IPEC-J2 cells markedly decreased, and epithelial cell integrity was compromised. However, COS pretreatment significantly reduced these changes. Low-concentration (200 µg/mL) COS up-regulated Toll-like receptor 4 (TLR4) and nuclear p65 expression, but inhibited LPS-induced expression of nuclear p65, IL-6, and IL-8. Addition of the TLR4 inhibitor reduced nuclear p65, IL-6, and IL-8 expression in IPEC-J2 cells exposed to COS or LPS alone, and a slight up-regulation in nuclear p65 was observed in COS and LPS co-treated cells. Medium-dose COS (600 mg/kg/d) protected against DSS-induced colitis, in which TLR4 and nuclear p65 expression levels were decreased. We postulate that the prevention of both LPS- and DSS -induced inflammatory responses in IPEC-J2 cells and mice by COS are related to the inhibition of the TLR4/NF-κB signaling pathway.

Protonation induced high-Tc phases in iron-based superconductors evidenced by NMR and magnetization measurements.

Chemical substitution during growth is a well-established method to manipulate electronic states of quantum materials, and leads to rich spectra of phase diagrams in cuprate and iron-based superconductors. Here we report a novel and generic strategy to achieve nonvolatile electron doping in series of (i.e. 11 and 122 structures) Fe-based superconductors by ionic liquid gating induced protonation at room temperature. Accumulation of protons in bulk compounds induces superconductivity in the parent compounds, and enhances the Tc largely in some superconducting ones. Furthermore, the existence of proton in the lattice enables the first proton nuclear magnetic resonance (NMR) study to probe directly superconductivity. Using FeS as a model system, our NMR study reveals an emergent high-Tc phase with no coherence peak which is hard to measure by NMR with other isotopes. This novel electric-field-induced proton evolution opens up an avenue for manipulation of competing electronic states (e.g. Mott insulators), and may provide an innovative way for a broad perspective of NMR measurements with greatly enhanced detecting resolution.

Human mesenchymal stromal cell-derived extracellular vesicles alleviate renal ischemic reperfusion injury and enhance angiogenesis in rats.

BACKGROUND: Mesenchymal stromal cells (MSCs) derived extracellular vesicles (EVs) were regarded as a potent medium for kidney injury repair and angiogenesis were regarded as an important step in tissue regeneration. However, the pro-angiogenesis effect of MSC-EVs in ischemia-reperfusion induced kidney injury and its potential mechanisms have yet to be determined. METHODS: EVs were isolated from the medium of human umbilical cord-derived MSCs (huMSCs) were injected in rats intravenously after unilateral kidney ischemia. Animals were sacrificed at 24 h and 2 weeks after injury. The renal functions and histology staining were examined to assess the therapeutic effect of the EVs. Moreover, we investigated the pro-angiogenesis effects of EVs in injured kidneys and tested the angiogenesis-related factors to further illuminate the probable mechanisms. RESULTS: It was observed that EVs could reduce cell apoptosis and enhances proliferation 24 h after kidney injury, meanwhile renal function was improved and the histological lesion was mitigated. Moreover, renal VEGF was up-regulated by EVs and HIF-1α was down-regulated. Further, the increase of capillary vessel density and reduce of renal fibrosis was observed after 2 weeks. In vitro, EVs could deliver human VEGF directly to renal tubular epithelial cells (TECs) and increase VEGF levels. Most important, all the beneficial effects of EVs were abrogated by RNase treated except for the delivery of human VEGF. CONCLUSIONS: Human MSC-EVs could protect against ischemic/reperfusion injury induced kidney injury through pro-angiogenesis effects in HIF-1α independent manner, and both the delivery of pro-angiogenesis related VEGF and RNAs were involved in this process.