Melatonin protects zebrafish pancreatic development and physiological rhythms from sodium propionate-induced disturbances via the hypothalamic-pituitary-thyroid axis.

BACKGROUND: The widespread use of sodium propionate as a preservative in food may affect public health. We aimed to assess the effects of sodium propionate on circadian rhythms and pancreatic development in zebrafish and the possible underlying mechanisms. RESULTS: In this experiment, we analyzed the relationship between circadian rhythms and pancreatic development and then revealed the role of the thyroid endocrine system in zebrafish. The results showed that sodium propionate interfered with the rhythmic behavior of zebrafish, and altered the expression of important rhythmic genes. Experimental data revealed that pancreatic morphology and developmental genes were altered after sodium propionate exposure. Additionally, thyroid hormone levels and key gene expression associated with the hypothalamic-pituitary-thyroid axis were significantly altered. Melatonin at a concentration of 1 µmol L-1, with a mild effect on zebrafish, observably alleviated sodium propionate-induced disturbances in circadian rhythms and pancreatic development, as well as regulating the thyroid system. CONCLUSION: Melatonin, while modulating the thyroid system, significantly alleviates sodium propionate-induced circadian rhythm disturbances and pancreatic developmental disorders. We further revealed the deleterious effects of sodium propionate as well as the potential therapeutic effects of melatonin on circadian rhythm, pancreatic development and the thyroid system. © 2024 Society of Chemical Industry.

Mitophagy Regulates the Circadian Rhythms by Degrading NR1D1 in Simulated Microgravity and Isolation Environments.

Long-term spaceflight is known to induce disruptions in circadian rhythms, which are driven by a central pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus, but the underlying molecular mechanisms remain unclear. Here, we developed a rat model that simulated microgravity and isolation environments through tail suspension and isolation (TSI). We found that the TSI environment imposed circadian disruptions to the core body temperature, heart rate, and locomotor-activity rhythms of rats, especially in the amplitude of these rhythms. In TSI model rats' SCNs, the core circadian gene NR1D1 showed higher protein but not mRNA levels along with decreased BMAL1 levels, which indicated that NR1D1 could be regulated through post-translational regulation. The autophagosome marker LC3 could directly bind to NR1D1 via the LC3-interacting region (LIR) motifs and induce the degradation of NR1D1 in a mitophagy-dependent manner. Defects in mitophagy led to the reversal of NR1D1 degradation, thereby suppressing the expression of BMAL1. Mitophagy deficiency and subsequent mitochondrial dysfunction were observed in the SCN of TSI models. Urolithin A (UA), a mitophagy activator, demonstrated an ability to enhance the amplitude of core body temperature, heart rate, and locomotor-activity rhythms by prompting mitophagy induction to degrade NR1D1. Cumulatively, our results demonstrate that mitophagy exerts circadian control by regulating NR1D1 degradation, revealing mitophagy as a potential target for long-term spaceflight as well as diseases with SCN circadian disruption.

Fluorene-9-bisphenol acts on the gut-brain axis by regulating oxytocin signaling to disturb social behaviors in zebrafish.

Previous studies have identified the exposure to ubiquitous environmental endocrine disruptors may be a risk factor of neurological disorders. However, the effects of fluorene-9-bisphenol (BHPF) in environmental exposure concentrations associated with these disorders are poorly understood. In this study, classic light-dark and social behavior tests were performed on zebrafish larvae and adults exposed BHPF exposure to evaluate social behavioral disorders and the microbiota-gut-brain axis was assessed to reveal the potential mechanisms underlying the behavioral abnormalities observed. Our results demonstrated that zebrafish larvae exposed to an environmentally relevant concentration (0.1 nM) of BHPF for 7 days showed a diminished response to external environmental factors (light or dark). Zebrafish larvae exposed to BHPF for 7 days or adults exposed to BHPF for 30 days at 1 µM displayed significant behavioral inhibition and altered social behaviors, including social recognition, social preference, and social fear contagion, indicating autism-like behaviors were induced by the exposure. BHPF exposure reduced the distribution of Nissl bodies in midbrain neurons and significantly reduced 5-hydroxytryptamine signaling. Oxytocin (OXT) levels and expression of its receptor oxtra in the gut and brain were down-regulated by BHPF exposure. In addition, the expression levels of genes related to the excitation-inhibitory balance of synaptic transmission changed. Microbiomics revealed increased community diversity and altered abundance of some microflora, such as an elevation in Bacillota and Bacteroidota and a decline in Mycoplasmatota in zebrafish guts, which might contribute to the abnormal neural circuits and autism-like behaviors induced by BHPF. Finally, the rescue effect of exogenous OXT on social behavioral defects induced by BHPF exposure was verified in zebrafish, highlighting the crucial role of OXT signaling through gut-brain axis in the regulatory mechanisms of social behaviors affected by BHPF. This study contributes to understanding the effects of environmental BHPF exposure on neuropsychiatric disorders and attracts public attention to the health risks posed by chemicals in aquatic organisms. The potential mental disorders should be considered in the safety assessments of environmental pollutants.

Electroacupuncture improves gastrointestinal motility through a central-cholinergic pathway-mediated GDNF releasing from intestinal glial cells to protect intestinal neurons in Parkinson's disease rats.

Constipation symptoms of Parkinson's disease (PD) seriously reduce the quality of life of patients and aggravate the development of the disease, but current treatment options still cannot alleviate the progress of constipation. Electroacupuncture (EA) is a new method for the treatment of constipation, which can effectively treat the symptoms of constipation in PD patients. However, the specific regulatory mechanisms of EA in the treatment of constipation symptoms in PD remain unclear. The aim of this study is to investigate the therapeutic effect of EA on PD constipation rats and its regulatory mechanism. A rotenone (ROT)-induced gastrointestinal motility disorder model was used to simulate the pathological process of constipation in PD. The results showed that EA could effectively promote gastrointestinal peristalsis, reduce α-synuclein accumulation in substantia nigra and colon and colonic injury in rats after ROT administration. Mechanistically, EA activation of the central-cholinergic pathway increases acetylcholine release in the colon. At the same time, EA up-regulated the co-expression of enteric glial cells (EGCs) and α7 nicotinic acetylcholine receptor (α7nAChR). EA increased the expression of choline acetyltransferase (ChAT), neuronal nitric oxide synthase (nNOS), and tyrosine hydroxylase (TH) in the colon of PD rats. Further mechanistic studies showed that EA increased the expression of glial cell-derived neurotrophic factor (GDNF), GFRa1 and p-AKT in colon tissues. The present study confirmed that EA upregulates α7nAChR through a central-cholinergic mechanism to promote GDNF release from EGCs, thereby protecting intestinal neurons and thereby improving gastrointestinal motility.

Effects of fluorene-9-bisphenol exposure on anxiety-like and social behavior in mice and protective potential of exogenous melatonin.

Fluorene-9-bisphenol (BHPF) is widely used in the manufacture of plastic products and potentially disrupts several physiological processes, but its biological effects on social behavior remain unknown. In this study, we investigated the effects of BHPF exposure on anxiety-like and social behavior in female mice and the potential mechanisms, thereby proposing a potential therapy strategy. We exposed female Balb/c mice to BHPF by oral gavage at different doses (0.5, 50 mg/kg bw/2-day) for 28 days, which were found BHPF (50 mg/kg) exposure affected motor activity in the open field test (OFT) and elevated cross maze (EPM), resulting in anxiety-like behaviors, as well as abnormal social behavioral deficits in the Social Interaction Test (SIT). Analysis of histopathological staining results showed that BHPF exposure caused damage to hippocampal neurons in the CA1/CA3/DG region and decreased Nissl pyramidal neurons in the CA1/CA3 regions of the hippocampus, as well as a decrease in parvalbumin neuron expression. In addition, BHPF exposure upregulated the expression of excitatory and inhibitory (E/I) vesicle transporter genes (Vglut1, Vglut2, VGAT, GAD67, Gabra) and axon growth gene (Dcc) in the mouse hippocampus. Interestingly, behavioral disturbances and E/I balance could be alleviated by exogenous melatonin (15 mg/kg bw/2-day) therapy. Our findings suggest that exogenous melatonin may be a potential therapy with protective potential for ameliorating or preventing BHPF-induced hippocampal neuronal damage and behavioral disturbances. This study provided new insight into the neurotoxicological effects on organisms exposed to endocrine-disrupting chemicals and aroused our vigilance in current environmental safety about chemical use.

Revealing bioresponses of biofilm and flocs to salinity gradient in halophilic biofilm reactor.

Understanding the different biological responses to salinity gradient between coexisting biofilm and flocs is crucial for regulating the ecological function of biofilm system. This study investigated performance, dynamics, and community assembly of biofilm system under 3 %-7% salinity gradient. The removal efficiency of NH4+-N remained stable and exceeded 93 % at 3 %-6% salinity, but decreased to below 80 % at 7 % salinity. The elevated salinity promoted the synthesis of extracellular polymer substrates, inhibited microbial respiration, and significantly regulated the microbial community structure. Compared to flocs, biofilm exhibited greater species diversity and richer Nitrosomonas. It was found diffusion limitations dominated the microbial community assembly under the salinity gradient. And microbial network revealed positive interactions predominated the microbial relationships, designating norank Spirochaetaceae, unclassified Micrococcales, Corynebacterium, and Pusillimonas as keystone species. Moreover, distinct salinity preferences in nitrogen transformation-related genes were observed. This study can improve the understanding to the regulation of biofilm systems to salt stresses.

Cytomorphology of metastatic malignant peripheral nerve sheath tumour present in pleural fluid: Case study and literature review.

The cytomorphology of MPNST in effusion specimens is rarely described. In this paper, the detailed cytopathological and immunohistochemical characteristics of metastatic MPNST has been described in pleural effusion. Patients' medical history and the judicious utilization of ancillary studies contribute to ensure precise cytological diagnoses. The cytomorphology of malignant peripheral nerve sheath tumour (MPNST) in effusion specimens can be diagnostically challenging. The author presents detailed cytopathological and immunohistochemical characteristics of a case of metastatic MPNST in pleural effusion.

Recovery mechanism of heterotrophic ammonia assimilation system under chromium hexavalent stress.

Heterotrophic ammonia assimilation (HAA), an innovative technology for high-salinity wastewater treatment, demonstrates self-recovery capability following Cr (VI) stress. This study investigated the inhibitory effects and self-restoration mechanisms of Cr (VI) at various stress levels. The removal efficiencies of NH4+-N and Cr (VI) in the HAA gradually decreased with increasing influent Cr (VI) concentration. Exposure to Cr (VI) increased the amounts of high-molecular-weight proteins in soluble microbial products and stimulated the generation of extracellular polymeric substances. Heterotrophic functional microorganisms with Cr (VI) tolerance, such as Marinobacter and Planktosalinus, were enriched. An assimilation pathway gene (glnA) and a Cr (VI)-related gene (atoB) were also upregulated. After ceasing Cr (VI) addition, the HAA system demonstrated a 17.1 % increase in the removal efficiency of NH4+-N, which was attributable to its self-recovery ability. This study provides a scientific and theoretical foundation for the HAA process in resisting the impact of heavy-metal-containing wastewater and self-recovery.

Alleviative effects of the parthenolide derivative ACT001 on insulin resistance induced by sodium propionate combined with a high-fat diet and its potential mechanisms.

The increasing side effects of traditional medications used to treat type II diabetes have made research into the development of safer and more effective natural medications necessary. ACT001, a derivative of parthenolide, has been shown to have good anti-inflammatory and antitumor effects; however, its role in diabetes is unclear. The short-chain fatty acid propionate is a common food preservative that has been found to cause disturbances in glucose metabolism in mice and humans. This study aimed to investigate whether sodium propionate could aggravate insulin resistance in obese mice and cause diabetes and to study the alleviative effects and potential mechanisms of action of ACT001 on insulin resistance in diabetic mice. Type II diabetic mice were adminietered sodium propionate combined with a high-fat diet (HFD + propionate) by gavage daily for four weeks. Biochemical analysis showed that ACT001 significantly affected blood glucose concentration in diabetic mice, mainly by downregulating the expression of phosphoenolpyruvate carboxykinase 2 and glucose-6-phosphatase. Meanwhile, the level of fatty acid-binding protein 4 in the liver was significantly decreased. ACT001 has a protective effect on the liver and adipose tissue of mice. In addition, the results of the running wheel experiment indicated that ACT001 alleviated the circadian rhythm disorder caused by insulin resistance to a certain extent. This study revealed the potential mechanism by which ACT001 alleviates insulin resistance and provides ideas for developing natural antidiabetic drugs.

Glyphosate drives autophagy-dependent ferroptosis to inhibit testosterone synthesis in mouse Leydig cells.

Glyphosate (GLY), a widely used herbicide, can adversely affect the male reproductive health by inhibiting testosterone synthesis. Ferroptosis is a form of iron-dependent oxidative cell death that contributes to inhibition of testosterone secretion. However, it still remains unclear whether ferroptosis is involved in GLY-inhibited testosterone synthesis. Hereby, an in vitro model of 1 mM GLY-exposed testicular Leydig (TM3) cells was established to elucidate this issue. Data firstly showed that GLY causes cytotoxicity and testosterone synthesis inhibition via ferroptosis, while accumulation of lipid peroxides due to intracellular ferrous ion (Fe2+) overload and glutathione depletion is confirmed as a determinant of ferroptosis. Blockage of ferroptosis via chelation of Fe2+ or inhibition of lipid peroxidation can markedly mitigate GLY-induced testosterone synthesis inhibition. Also, autophagy activation is revealed in GLY-treated TM3 cells and nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy is involved in ferroptosis through the release of excess Fe2+. GLY-induced cytotoxicity and testosterone synthesis inhibition are significantly alleviated by NCOA4 knockdown, demonstrating the crucial role of NCOA4-mediated ferritinophagy in GLY-inhibited testosterone synthesis. In summary, this study provides solid evidence that NCOA4-mediated ferritinophagy promotes ferroptosis to inhibit testosterone synthesis, highlighting that targeting NCOA4 may be a potential therapeutic approach in GLY-induced male reproductive toxicity.

Camouflaging attenuated Salmonella by cryo-shocked macrophages for tumor-targeted therapy.

Live bacteria-mediated antitumor therapies mark a pivotal point in cancer immunotherapy. However, the difficulty in reconciling the safety and efficacy of bacterial therapies has limited their application. Improving bacterial tumor-targeted delivery while maintaining biosafety is a critical hurdle for the clinical translation of live microbial therapy for cancer. Here, we developed "dead" yet "functional" Salmonella-loaded macrophages using liquid nitrogen cold shock of an attenuated Salmonella typhimurium VNP20009-contained macrophage cell line. The obtained "dead" macrophages achieve an average loading of approximately 257 live bacteria per 100 cells. The engineered cells maintain an intact cellular structure but lose their original pathogenicity, while intracellular bacteria retain their original biological activity and are delay freed, followed by proliferation. This "Trojan horse"-like bacterial camouflage strategy avoids bacterial immunogenicity-induced neutrophil recruitment and activation in peripheral blood, reduces the clearance of bacteria by neutrophils and enhances bacterial tumor enrichment efficiently after systemic administration. Furthermore, this strategy also strongly activated the tumor microenvironment, including increasing antitumor effector cells (including M1-like macrophages and CD8+ Teffs) and decreasing protumor effector cells (including M2-like macrophages and CD4+ Tregs), and ultimately improved antitumor efficacy in a subcutaneous H22 tumor-bearing mouse model. The cryo-shocked macrophage-mediated bacterial delivery strategy holds promise for expanding the therapeutic applications of living bacteria for cancer.

Sacral Nerve Stimulation Alleviates Intestinal Inflammation Through Regulating the Autophagy of Macrophages and Activating the Inflammasome Mediated by a Cholinergic Antiinflammatory Pathway in Colitis Rats.

BACKGROUND: Inflammatory bowel disease (IBD) is characterized by chronic progressive intestinal inflammation. Sacral nerve stimulation (SNS) ameliorates colon inflammation caused by IBD. The aim of this study was to investigate the antiinflammatory benefits of SNS in colitis rats and explore the roles of the cholinergic antiinflammatory pathway, macrophage autophagy, and nucleotide oligomerization domain-like receptor thermal protein domain associated protein 3 (NLRP3) inflammatory bodies. MATERIALS AND METHODS: Rats were divided into four groups: healthy control, dextran sulfate sodium (DSS), DSS + sham-SNS, and DSS + SNS groups. An electrode was surgically placed in the right sacral nerve (S3) for stimulation. The disease activity index (DAI) score was recorded each day, and the degree of inflammatory injury was evaluated using hematoxylin and eosin staining. The alpha7 nicotinic acetylcholine receptor (α7nAChR) and autophagy- and NLRP3-related factors were assessed using immunofluorescence staining and Western blotting. RESULTS: The DSS group showed a higher DAI score, colon shortening, upregulated proinflammatory action, and colon damage, and the DSS + SNS group showed significantly improved symptoms. The number of α7nAChR+ cells and the expression level of autophagy decreased in the DSS group but increased in the DSS + SNS group. Conversely, the DSS group showed increased activation of NLRP3 inflammatory bodies, whereas the DSS + SNS group showed decreased activation of NLRP3 inflammatory bodies. CONCLUSION: In this study, SNS ameliorated colon inflammation by enhancing macrophage autophagy and inhibiting the activation of NLRP3 inflammatory bodies, which may be related to the opening of the cholinergic antiinflammatory pathway.

Neuromodulation and Functional Gastrointestinal Disease.

INTRODUCTION: Functional gastrointestinal disorders (FGIDs) are common, and they severely impair an individual's quality of life. The mechanism of pathogenesis and the effective treatments for FGIDs remain elusive. Neuromodulation-a relatively new treatment-has exhibited a good therapeutic effect on FGIDs, although there are different methods for different symptoms of FGIDs. MATERIALS AND METHODS: We used PubMed to review the history of neuromodulation for the treatment of FGIDs and to review several recently proposed neuromodulation approaches with improved effects on FGIDs. CONCLUSION: Electroacupuncture, transcutaneous electroacupuncture, transcutaneous auricular vagal nerve stimulation, sacral nerve stimulation (SNS) (which relies on vagal nerve stimulation), and gastric electrical stimulation (which works through the modulation of slow waves generated by the interstitial cells of Cajal), in addition to the noninvasive neurostimulation alternative approach method of SNS-tibial nerve stimulation and transcutaneous electrical stimulation (which is still in its infancy), are some of the proposed neuromodulation approaches with improved effects on FGIDs. This review has discussed some critical issues related to the selection of stimulation parameters and the underlying mechanism and attempts to outline future research directions backed by the existing literature.

LncRNA109897-JrCCR4-JrTLP1b forms a positive feedback loop to regulate walnut resistance against anthracnose caused by Colletotrichum gloeosporioides.

Walnut anthracnose induced by Colletotrichum gloeosporioides is a disastrous disease that severely restricts the development of the walnut industry in China. Long non-coding RNAs (lncRNAs) are involved in adaptive responses to disease, but their roles in the regulation of walnut anthracnose resistance response are not well defined. In this study, transcriptome analysis demonstrated that a C. gloeosporioides-induced lncRNA, lncRNA109897, located upstream from the target gene JrCCR4, upregulated the expression of JrCCR4. JrCCR4 interacted with JrTLP1b and promoted its transcriptional activity. In turn, JrTLP1b induced the transcription of lncRNA109897 to promote its expression. Meanwhile, transient expression in walnut leaves and stable transformation of Arabidopsis thaliana further proved that lncRNA, JrCCR4, and JrTLP1b improve the resistance of C. gloeosporioides. Collectively, these findings provide insights into the mechanism by which the lncRNA109897-JrCCR4-JrTLP1b transcriptional cascade regulates the resistance of walnut to anthracnose.

Specific interaction based drug loading strategies.

Drug carriers have been commonly used for drug control release, enhancing drug efficacy and/or minimizing side-effects. However, it is still difficult to get a high loading efficiency when encapsulating super hydrophilic drugs with a narrow therapeutic index, such as many neurotoxins. Increasing the carrier proportion can improve drug loading to a certain degree, while the burst released drug when the formulation enters the body may cause overdose side-effects. Moreover, high-dose carriers themselves may increase the metabolic burden of the body. Hence, new drug carriers and/or loading strategies are urgently needed to promote the applications of these drugs. This minireview will introduce drug loading strategies based on specific interactions (between drugs and carriers) and will discuss the challenges and perspectives of these strategies. This work is expected to provide alternative inspiration for the delivery of hydrophilic drugs.

Wogonin inhibits hepatoma cell proliferation by targeting miR-27b-5p/YWHAZ axis.

Wogonin (5,7-dihydroxy-8-methoxyflavone), a natural flavonoid compound in herbal plants, can suppress growth in hepatocellular carcinoma (HCC). However, the microRNA (miRNA) expression profiles that are influenced by wogonin have not been thoroughly described. To explore the novel miRNAs and the biological mechanism underlying the effect of wogonin on HCC cells. The effect of wogonin on Huh7 cell growth was assessed both in vitro and in vivo. The expression profiles of miRNAs were obtained by small RNA sequencing. Luciferase reporter experiment and bioinformatics analysis were conducted to determine whether tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) can bind to miR-27b-5p. Effects of the ectopic expression of YWHAZ and miR-27b-5p on Huh7 cells proliferation and apoptosis were evaluated. Furthermore, the cell cycle, apoptosis and multiple signaling pathway-related molecules were detected by Western blot analysis. Wogonin substantially inhibited the growth of Huh7 cells both in vitro and in vivo. Seventy miRNAs exhibited greater than twofold changes in wogonin-treated cells. Upregulation of miR-27b-5p inhibited Huh7 cell proliferation, and the anticancer effect of wogonin was reversed after miR-27b-5p knockdown. miR-27b-5p directly targeted YWHAZ in HCC cells. The proliferation-inhibiting effect of miR-27b-5p was revoked by YWHAZ overexpression. Meanwhile, inhibition of HCC growth was achieved by downregulating YWHAZ. Wogonin exerted antitumor activity through multiple signaling molecules, such as focal adhesion kinase, protein kinase B, mammalian target of rapamycin and molecules related to apoptosis and cell cycle by upregulating miR-27b-5p and downregulating YWHAZ. Our findings suggest that miR-27b-5p/YWHAZ axis contributes to the inhibitory effect of wogonin in HCC by targeting related genes and multiple signaling pathways.

Enhanced degradation of petroleum in saline soil by nitrogen stimulation and halophilic emulsifying bacteria Bacillus sp. Z-13.

Remediation of petroleum-contaminated soil is a widely concerned challenge. As an ecofriendly method, the performance improvement of indigenous microbial degradation is facing the bottleneck. In this study, a strain with high efficiency of petroleum degradation was isolated from the petroleum-contaminated soil and identified and named as Bacillus sp. Z-13. The strain showed the ability to produce lipopeptide surfactant which could improve 66% more petroleum hydrocarbons eluted. Strain Z-13 and its biosurfactant exhibited broad environmental adaptability to salinity (0-8%), pH (6-9) and temperature (15-45 °C). With the addition of strain Z-13 and the stimulation of NH4Cl, up to 59% of the petroleum in the contaminated soil was removed at the carbon to nitrogen ratio of 10. Microbial community analysis showed that petroleum-degrading bacteria, represented by Bacillus, became the dominant species at genus level and played an important role in the remediation. Additionally, ammonium stimulation facilitated both pathways of ammonium assimilation and nitrification in native microorganisms to achieve efficient degradation of petroleum hydrocarbons. This study could provide a promising approach for stable, environmental-friendly and efficient remediation of petroleum-contaminated soil.

Correction: 6-Gingerol as an arginase inhibitor prevents urethane-induced lung carcinogenesis by reprogramming tumor supporting M2 macrophages to M1 phenotype.

Correction for '6-Gingerol as an arginase inhibitor prevents urethane-induced lung carcinogenesis by reprogramming tumor supporting M2 macrophages to M1 phenotype' by Jingjing Yao et al., Food Funct., 2018, 9, 4611-4620, https://doi.org/10.1039/C8FO01147H.

Experimental investigation on fracturing effects in hydraulic sand fracturing with acoustic emission and 3d laser scanning.

Due to the extremely low permeability of shale reservoirs, large-scale reservoir fracturing is required. Hydraulic fracturing is one of the most important technologies in shale gas exploration and development. In this paper, the acoustic emission energy and the number of location and fracture surface morphology of specimens before and after fracture are studied through hydraulic sand fracturing test. The test results show that: (1) the energy ratio obtained during hydraulic fracturing without proppant is the smallest, and increasing the confining pressure, as well as reducing the displacement and viscosity of the fracturing fluid will cause the energy ratio to decrease. From the perspective of acoustic emission energy, the proppant play an important role in the generation of fractures during hydraulic sand fracturing; (2) when the confining pressure increases, the number of shale specimens before and after rupture is the largest, but the total number of locating events is smaller than the sanding ratio increased; there is no proppant hydraulic fracturing, the number of specimens before and after the rupture is the largest. And the total number reached the minimum, indicating that the proppant can play an important role in the hydraulic sand fracturing test; (3) the sand is relatively large, the specific surface and standard deviation both reach the maximum, indicating that the fracture surface roughness is the largest under the test condition, and the fracturing effect is the best, but the specific surface and standard deviation are the minimum when fracturing without proppant, so indicating that the fracture surface fracturing effect is the worst at this time.

Néel Spin Currents in Antiferromagnets.

Ferromagnets are known to support spin-polarized currents that control various spin-dependent transport phenomena useful for spintronics. On the contrary, fully compensated antiferromagnets are expected to support only globally spin-neutral currents. Here, we demonstrate that these globally spin-neutral currents can represent the Néel spin currents, i.e., staggered spin currents flowing through different magnetic sublattices. The Néel spin currents emerge in antiferromagnets with strong intrasublattice coupling (hopping) and drive the spin-dependent transport phenomena such as tunneling magnetoresistance (TMR) and spin-transfer torque (STT) in antiferromagnetic tunnel junctions (AFMTJs). Using RuO_{2} and Fe_{4}GeTe_{2} as representative antiferromagnets, we predict that the Néel spin currents with a strong staggered spin polarization produce a sizable fieldlike STT capable of the deterministic switching of the Néel vector in the associated AFMTJs. Our work uncovers the previously unexplored potential of fully compensated antiferromagnets and paves a new route to realize the efficient writing and reading of information for antiferromagnetic spintronics.