Search

Abstract The subcortical maternal complex (SCMC) is essential for safeguarding female fertility in mammals. Assembled in oocytes, the SCMC maintains the cleavage of early embryos, but the underlying mechanism remains unclear. Here, we report that 14-3-3, a multifunctional protein, is a component of the SCMC. By resolving the structure of the 14-3-3-containing SCMC, we discover that phosphorylation of TLE6 contributes to the recruitment of 14-3-3. Mechanistically, during maternal-to-embryo transition, the SCMC stabilizes 14-3-3 protein and contributes to the proper control of CDC25B, thus ensuring the activation of the maturation-promoting factor and mitotic entry in mouse zygotes. Notably, the SCMC establishes a conserved molecular link with 14-3-3 and CDC25B in human oocytes/embryos. This study discloses the molecular mechanism through which the SCMC regulates the cell cycle in early embryos and elucidates the function of the SCMC in mammalian early embryogenesis.

Abstract Glycosylphosphatidylinositol (GPI) acyltransferase is crucial for the synthesis of GPI-anchored proteins. Targeting the fungal glycosylphosphatidylinositol acyltransferase GWT1 by manogepix is a promising antifungal strategy. However, the inhibitory mechanism of manogepix remains unclear. Here, we present cryo-EM structures of yeast GWT1 bound to the substrate (palmitoyl-CoA) and inhibitor (manogepix) at 3.3 Å and 3.5 Å, respectively. GWT1 adopts a unique fold with 13 transmembrane (TM) helixes. The palmitoyl-CoA inserts into the chamber among TM4, 5, 6, 7, and 12. The crucial residues (D145 and K155) located on the loop between TM4 and TM5 potentially bind to the GPI precursor, contributing to substrate recognition and catalysis, respectively. The antifungal drug, manogepix, occupies the hydrophobic cavity of the palmitoyl-CoA binding site, suggesting a competitive inhibitory mechanism. Structural analysis of resistance mutations elucidates the drug specificity and selectivity. These findings pave the way for the development of potent and selective antifungal drugs targeting GWT1.

Abstract Spermiogenesis, the complex transformation of haploid spermatids into mature spermatozoa, relies on precise spatiotemporal regulation of gene expression at the post-transcriptional level. The mechanisms underlying this critical process remain incompletely understood. Here, we identify centrosomal protein 112 (CEP112) as an essential regulator of mRNA translation during this critical developmental process. Mutations in CEP112 are discovered in oligoasthenoteratospermic patients, and Cep112-deficient male mice recapitulate key phenotypes of human asthenoteratozoospermia. CEP112 localizes to the neck and atypical centrioles of mature sperm and forms RNA granules during spermiogenesis, enriching target mRNAs such as Fsip2, Cfap61, and Cfap74. Through multi-omics analyses and the TRICK reporter assay, we demonstrate that CEP112 orchestrates the translation of target mRNAs. Co-immunoprecipitation and mass spectrometry identify CEP112’s interactions with translation-related proteins, including hnRNPA2B1, EEF1A1, and EIF4A1. In vitro, CEP112 undergoes liquid-liquid phase separation, forming condensates that recruit essential proteins and mRNAs. Moreover, variants in patient-derived CEP112 disrupt phase separation and impair translation efficiency. Our results suggest that CEP112 mediates the assembly of RNA granules through liquid-liquid phase separation to control the post-transcriptional expression of fertility-related genes. This study not only clarifies CEP112’s role in spermatogenesis but also highlights the role of phase separation in translational regulation, providing insights into male infertility and suggesting potential therapeutic targets.

In-situ stress is a core factor controlling dynamic gas disasters in coal mines. Existing in-situ stress models are primarily based on the elastic properties of coal-rock formations and are not suitable for viscoelastic coal media. There is a need to establish an in-situ stress distribution model suitable for viscoelastic coal properties. Coal seams, especially tectonic coal, exhibit significant creep and stress relaxation characteristics. In this study, a Fractional Maxwell stress relaxation mathematical model was developed for viscoelastic coal reservoirs. The stress component of the extended Eaton model was improved to account for the stress relaxation in viscoelastic coal seams and an in-situ stress distribution model was established for viscoelastic coal seams. The results indicate that over geological time scales, viscoelasticity significantly affects the differential stress in coal seams. The degree of coal body creep and stress relaxation increases with the increase in viscosity coefficient and fractional order factor. As the elastic modulus decreases, the Poisson’s ratio, tectonic ratio, and gas pressure increase. The stress characteristics of coal seams exhibit a trend of hydrostatic pressure state distribution. Among them, the elastic modulus and Poisson's ratio contribute significantly to the difference between vertical principal stress and horizontal stress. The tectonic ratio contributes significantly to the difference between horizontal stresses. Gas pressure contributes equally to all three principal stresses. The stress relaxation effect can alter the relative magnitudes of maximum and minimum horizontal principal stresses and reduce stress anisotropy. Based on the critical stress model, a reduction in friction coefficient and an increase in gas pressure were similarly observed in coal seams under different in-situ stress conditions, leading to an approach towards hydrostatic pressure distribution. The mechanical properties of tectonic coal are more conducive to approaching hydrostatic pressure states over geological time scales. The application of the in-situ stress model established in this study validated the field measurements and provided new insights into gas enrichment and permeability reduction in tectonic coal.

Several fungal pathogens cause root rot of common bean, among which Fusarium spp. are the most common pathogens causing Fusarium root rot (FRR) worldwide. FRR has been becoming an increasingly severe disease of common bean in China, but the species of Fusarium spp. have remained unclear. Thus, this study was performed to identify the pathogen causing common bean root rot in Liangcheng County, Inner Mongolia, China. Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification. The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean, while 11 other isolates were not pathogenic. The eight pathogenic isolates, FCL1–FCL8, were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α, ITS, 28S, and IGS regions. Host range test showed that the representative F. cuneirostrum isolate FCL3 was also pathogenic to mung bean, while not pathogenic to adzuki bean, chickpea, cowpea, faba bean, pea, and soybean. Moreover, 50 common bean and 50 mung bean cultivars were screened for resistance to FRR, and seven highly resistant or resistant cultivars of common bean were identified, while no resistant cultivars of mung bean were screened. This study revealed that F. cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well. To our knowledge, this is the first report of F. cuneirostrum causing FRR of common bean in China.

Chickpea (Cicer arietinum L.) is an important legume crop worldwide. An emerging disease, basal stem rot with obvious wilt symptoms, was observed in the upper part of chickpea plants during the disease survey in Qiubei County of Yunnan Province. Three fungal isolates (ZD36-1, ZD36-2, and ZD36-3) were obtained from the diseased tissue of chickpea plants collected from the field. Those isolates were morphologically found to be similar to Diaporthe aspalathi. Molecular sequence analyses of multiple gene regions (ITS, tef1, tub2, cal, and his3) indicated that the three isolates showed a high identity with D. aspalathi. Pathogenicity and host range tests of the isolates were performed on the original host chickpea and eight other legume crops. The isolates were strongly pathogenic to chickpea and appeared highly pathogenic to soybean, cowpea, and mung bean; moderated or mild pathogenic to adzuki bean and common bean; however, the isolates did not cause symptoms on grass pea (Lathyrus sativus). Diaporthe aspalathi was previously reported as a main pathogen causing the southern stem canker in soybean. To our knowledge, this is the first report of D. aspalathi inducing basal stem rot on chickpea worldwide.

PfENT1 is a promising antimalarial drug target. Here, authors report cryo-EM structures of PfENT1 that, together with biochemical work, suggests PfENT1 is an inosine transporter and describe the inhibitory mechanism of the endofacial inhibitor, GSK4.

Background: Hypertension affects over 1 billion people globally and is the top risk factor of cardiovascular morbidity and mortality. Wuweijiangyasan (WWJYS), as an empirical prescription, has stable depressurization effects. This study investigated the chemical composition and pharmacodynamic effects of WWJYS in regulating the blood pressure (BP), emotion, and blood lipid of spontaneous hypertensive rats, and further explored the depressurization mechanism of WWJYS. Materials and Methods: This study used network pharmacology to identify the origins and predict targets of WWJYS, and artificial intelligence-based molecular docking is used to further predict targets and mechanisms. The chemical constituents of WWJYS were analyzed and identified by ultra high-performance liquid chromatography–mass spectrometry (MS)/MS. Results: In the WWJYS group, the systolic BP level significantly was decreased, and the HR was stable. The irritability became stable after the 5-week treatment compared with the model group (P < 0.05). Rats' rotation tolerance time increased after 2-weeks stabilization. Compared with the model group, angiotensin-converting enzyme 2 protein and mRNA of the WWJYS group increased significantly (P < 0.05). Network pharmacology collected 64 compounds and identified 22 potential targets of WWJYS for antihypertensive activity. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that WWJYS might regulate smooth muscle cells, affect inflammatory response and improve endothelial function through multiple pathways. The molecular docking study further supported that the target proteins have good combinations with the main active components of WWJYS. Conclusions: The data indicated that WWJYS had significant depressurization, analgesic, and sedative, as well as lipid-lowering effects, and the depressurization mechanism of WWJYS may function in multiple signal pathways, especially in improving blood vessel function and intervening inflammation.

White mold of pea caused by Sclerotinia sclerotiorum is a common disease in China. However, we discovered that the diverse Sclerotinia species could cause white mold on pea plants in Chongqing and Sichuan of China during recent disease surveys. Thus, the objective of this study was to confirm the causal agents from diseased pea plants. The obtained isolates of white mold from Chongqing and Sichuan were identified by morphological characters and molecular characterization to determine the pathogen species, and their pathogenicity was confirmed on pea through completing Koch's postulates. Fungal isolates of Sclerotinia-like were obtained from diseased plants or sclerotia. Based on morphological characteristics and molecular characterization, 30 isolates were identified to three species, six isolates as S. minor, seven as S. sclerotiorum, and 17 as S. trifoliorum. In pathogenicity tests on pea cultivars Zhongwan 4 and Longwan 1, all 30 isolates caused typical symptoms of white mold on the inoculated plants, and the inoculated pathogens were re-isolated from the diseased plants. This study confirmed that white mold of pea was caused by three Sclerotinia species, S. sclerotiorum, S. minor and S. trifoliorum in Chongqing and Sichuan. It is the first report that S. minor and S. trifoliorum cause white mold of pea in Southwest China.

Steroid 5α-reductase 2 (SRD5A2), a testosterone metabolism enzyme, is implicated in human disease. Structural and biochemical analyses of PbSRD5A, a bacterial homolog, reveal SRD5A2 substrate binding pocket and provide framework for the design of new drugs targeting this enzyme.

Abstract Background Drug resistance in China is becoming a more and more serious issue. Infection by drug-resistant bacteria has become a major disease that seriously threatens the health of Chinese people and affects national medical finance. Therefore, it is of great scientific and clinical significance to actively carry out research on the prevention and treatment of infections by multi-drug resistant organisms (MDRO). Previous studies by the authors suggested that patients with hospital-acquired pneumonia caused by MDRO mostly showed the pathological state of “insufficient healthy Qi and internal accumulation of pathogenic Qi” and “acute deficiency syndrome” mainly characterized by Qi deficiency. Buzhong Yiqi decoction is a famous classic prescription in traditional Chinese medicine (TCM) for treating internal damage fever. This study intends to provide an evidence-based rationale for Buzhong Yiqi decoction in treating MDRO hospital-acquired pneumonia by conducting a multi-center randomized controlled clinical study. Methods/design This study is designed to be a multi-center randomized controlled study in which patients are assigned randomly into control (standard therapy) and trial (standard therapy plus Buzhong Yiqi decoction) groups. The patients will be selected from the emergency department and the ICU inpatient department of five study sites and will all be diagnosed with MDRO hospital-acquired pneumonia and meet the inclusion criteria. Forty patients are to be enrolled in each study site, resulting in a total of 200 patients in the study. The treatment course is 28 days. Discussion In this study: (1) the theory of “acute Qi deficiency” in MDRO hospital-acquired pneumonia is put forward for the first time, and the basic theories of TCM are further improved; (2) a multi-center randomized controlled clinical study will be performed for the first time with Buzhong Yiqi decoction, the classic prescription for reinforcing healthy Qi and eliminating pathogenic Qi, providing a reliable evidence-based rationale for the treatment of MDRO pulmonary infection with TCM; (3) the clinical application and modern disease spectrum of Buzhong Yiqi decoction is expanded, and the scientific notion of “treating different diseases with the same method” is enriched further. Trial registration China Clinical Trial Registry, ChiCTR1900022429. Registered on April 11, 2019. http://www.chictr.org.cn/listbycreater.aspx.

Plasmodium falciparum, the deadliest causal agent of malaria, caused more than half of the 229 million malaria cases worldwide in 2019. The emergence and spreading of frontline drug-resistant Plasmodium strains are challenging to overcome in the battle against malaria and raise urgent demands for novel antimalarial agents. The P. falciparum formate-nitrite transporter (PfFNT) is a potential drug target due to its housekeeping role in lactate efflux during the intraerythrocytic stage. Targeting PfFNT, MMV007839 was identified as a lead compound that kills parasites at submicromolar concentrations. Here, we present 2 cryogenic-electron microscopy (cryo-EM) structures of PfFNT, one with the protein in its apo form and one with it in complex with MMV007839, both at 2.3 Å resolution. Benefiting from the high-resolution structures, our study provides the molecular basis for both the lactate transport of PfFNT and the inhibition mechanism of MMV007839, which facilitates further antimalarial drug design.

Fuyuan Xingnao decoction (FYXN), a traditional Chinese formula comprised of seven herbs, has been utilized to treat diabetes mellitus complicated with cerebral infarction (DMCI) for years. Yet, its protective and regulatory mechanism is poorly understood. The aim of the study is to investigate the effects of FYXN on DMCI in vitro and in vivo, as well as its mechanism in angiogenesis. For in vivo experiments, FYXN was administered to DMCI rats with streptozotocin (STZ) injection-induced diabetes. Then middle cerebral artery occlusion (MCAO) was conducted and the cerebral cortex sections of the rats were obtained. The ultrastructure of cerebral microvessels and new vessel density of ischemic penumbra were evaluated by the transmission electron microscopy (TEM) assay and immunohistochemistry, respectively. Protein and mRNA expression levels of Rab1/AT1R in cortex were assayed by Western blotting and real-time fluorescence quantitative real-time polymerase chain reaction (RT-qPCR). In vitro, FYXN serum was produced in rats on the fourth day 2 h after the last FYXN administration. Green fluorescence was observed after transfection with lentivirus packaged Rab1-WT or siRNA for 24 h. The activity of brain microvascular endothelial cells (BMECs) treated with sera from these rats was tested by MTT assay and Transwell assays, respectively. The expression of AT1R on the cell membrane and endoplasmic reticulum of BMECs was evaluated by immunofluorescence staining. Protein expression levels of signaling molecules in the Rab1/AT1R pathways were also detected. Results showed that in vivo, FYXN treatment significantly intensified CD31 staining in the cortical areas and enhanced the mRNA and protein levels of AT1R, Ang II, Rab1a, Rab1b and VEGF expression in ischemic cerebral cortex tissues. In vitro, the expression levels of AT1R, Ang II, Rab1a, Rab1b and VEGF in the cerebral infarction model group were significantly higher than those in the control group, with further increases after administration of FYXN drug serum. FYXN promoted the proliferation and migration of BMECs by activating the Rab1/AT1R signaling pathway. In conclusion, FYXN exerts a protective effect against DMCI by promoting angiogenesis via the Rab1/AT1R pathway, which provides strong evidence for the therapeutic effect of FYXN on DMCI.

Concentrative nucleoside transporters (CNTs), members of the solute carrier (SLC) 28 transporter family, facilitate the salvage of nucleosides and therapeutic nucleoside derivatives across the plasma membrane. Despite decades of investigation, the structures of human CNTs remain unknown. We determined the cryogenic electron microscopy (cryo-EM) structure of human CNT (hCNT) 3 at an overall resolution of 3.6 Å. As with its bacterial homologs, hCNT3 presents a trimeric architecture with additional N-terminal transmembrane helices to stabilize the conserved central domains. The conserved binding sites for the substrate and sodium ions unravel the selective nucleoside transport and distinct coupling mechanism. Structural comparison of hCNT3 with bacterial homologs indicates that hCNT3 is stabilized in an inward-facing conformation. This study provides the molecular determinants for the transport mechanism of hCNTs and potentially facilitates the design of nucleoside drugs.

Fusarium wilt (FW), caused by Fusarium oxysporum f. sp. pisi (Fop), has always been an important disease affecting pea production and causing severe yield losses in most pea-growing areas worldwide. Growing resistant pea cultivars is the most economical and effective method for controlling the disease. In this study, firstly, 21 Fusarium oxysporum isolates were identified as races 1 and 5 of Fop based on morphological and molecular characteristics, and the disease reactions of seven pea differential cultivars. Then, a detailed resistance evaluation strategy was established and validated by a death rate score, disease index, and percentage of leaves showing symptoms for each individual plant. Finally, a 1311 pea germplasm collection including 740 accessions from China and 571 accessions aboard or unknown sources was evaluated for resistance to a representative isolate PF22b of Fop race 5, and the results showed that 28 accessions and 164 accessions were highly resistant (HR) and resistant (R), respectively. Among these resistance accessions, 13 HR and 44 R accessions were collected from 19 provinces in China, most of which came from Sichuan, Tibet, and Gansu Provinces. The 15 HR and 120 R accessions were collected in 10 countries outside China or unknown sources, the majority of which came from the United States, Australia, and Russia. The findings would provide important information for using resistance pea cultivars to control Fusarium wilt. Incorporating these resistance accessions into breeding programs will contribute to improving the Fop resistance of pea cultivars.

Powdery mildew is one of the severe diseases on common bean in Southwestern China, but the identity of the pathogen inciting this disease is unclear. The objective of this study was to identify the causal agent of common bean powdery mildew and to screen resistant cultivars. The pathogen was identified through morphological identification, molecular phylogenetic analysis, and pathogenicity tests. Resistance of common bean cultivars was evaluated by artificial inoculation at the seedling stage. The common bean powdery mildew isolate CBPM1 was obtained after pathogen isolation and purification. Morphological identification confirmed that the isolate CBPM1 belonged to the Oidium subgenus Pseudoidium and germinated Pseudoidium-type germ tubes. Molecular phylogenetic analysis showed that the isolate CBPM1 and Erysiphe vignae isolates from different hosts were clustered into a distinct group. The pathogenicity and host range tests revealed that the isolate CBPM1 was strongly pathogenic to common bean, multiflora bean, lablab bean, cowpea, and mung bean, but not to soybean, adzuki bean, pea, faba bean, chickpea, lentil, pumpkin, and cucumber. In addition, 54 common bean cultivars were identified for resistance to powdery mildew, and 15 were resistant or segregant. Based on the morphological, molecular and pathogenic characteristics, the causal agent of common bean powdery mildew was identified as E. vignae. This is the first time E. vignae has been confirmed on common bean. Cultivars with different resistance levels were screened, and these cultivars could be used for disease control or the breeding of new resistant cultivars.

Objective: To find the target genes in combination of astragalus root (Astragalus membranaceus) and spindle tree wings (Euonymus alatus (THUNB.) SIEB.) (Qijian Heji) with the function of regulating blood glucose levels in kk mice by real-time fluorescence quantitative PCR (RT-PCR). To achieve the primary exploration on the material basis for Qijian Heji to improve the blood glucose levels of type 2 diabetic kk mice. Methods: We applied RT-PCR to detecting the expression of gene targets in kidney tissues of type 2 diabetes model kk mice. The detected gene targets were predicted by the network pharmacology method in the early stage of the project. Through the observation of the hypoglycemic effect of different ratios of Qijian Heji, the optimal proportion was determined and then used to conduct research of material basis. Results: Continuous administration of Qijian Heji (astragalus root: spindle tree wings = 3:1) for six weeks resulted in significantly lowering blood glucose levels in mice in the fourth week, dropping from 33.3 to 21.9 mmol/L; this lower level was maintained in the fifth to sixth weeks. Blood glucose values in the positive drug group decreased from 33.3 to 21.85 mmol/L in the fourth week and maintained steady decreasing in the fifth and sixth weeks. Conclusion: Qijian Heji, with proportion of 3:1, could significantly reduce the blood glucose values in kk mice, animal experiment results verified the accurate prediction of network pharmacology, and at the same time, it is verified there was a certain therapeutic effect about the combination of the two herbs on reducing the glucose value. Animal experiments and RT-PCR results showed that Qijian Heji conducted a hypoglycemic effect by modulating estrogen receptor (ESR1) and renin (REN) expression.

Objective: To evaluate the efficacy of traditional Chinese herbs on heart failure (HF) using nuclear magnetic resonance (NMR) metabolomics. Methods: Plasma metabolomics was conducted on both patients with HF and healthy controls. The partial least squares model was applied to determine potential metabolic markers and related metabolic pathways of the disease. HF patients with the traditional Chinese syndrome pattern of qi deficiency and blood stasis were divided into two groups, and treated, respectively, with conventional medicine and a combination of conventional and Chinese herbs, aimed at tonifying qi and activating blood. Healthy participants served as a control group for comparison. Results and conclusion: Both conventional and herbal treatments appear to regulate disorders of amino acid and glucose metabolism. Combined treatment appears to be more comprehensive, indicating that herbal and conventional medicines exert their effects through different mechanisms in treating HF. It can be further inferred that herbs that tonify qi and activate blood may regulate different essential metabolites.

Background: Chronic heart failure (CHF) is characterized by insufficient blood supply from heart to meet the body's metabolic demands. Integrating Western and traditional Chinese medicine to treat CHF has proved a validated therapeutic approach. In recent years, metabolomics has been regarded as a potential platform to provide biomarkers for disease-subtypes. Objective: To examine 38 patients, combined NMR plasma metabolomics and traditional Chinese medicine diagnosis in order to identify diagnostic biomarkers for two CHF syndrome subtypes. Methods: After processing the spectra, orthogonal partial least square discriminant analysis was performed, and the contributing NMR signals were analyzed using Y-scrambling statistical validation with good reliability. Results: Plasma metabolic patterns of yin deficiency and yang deficiency patients were clearly discriminated. The yin-deficiency group had increased level of lactate, glycoprotein, lipoprotein and lower levels of glucose, valine and proline. The yang-deficiency group had higher levels of lactate, glycoprotein and pyruvic acid, and lower levels of glucose and lipoprotein. Potential biomarkers of CHF based on the two traditional Chinese medicine syndromes indicated alternative modes of metabolites and metabolic pathways in the disease, e.g. dysfunction of energy utilization and disturbance in fatty acids, amino acids. Conclusion: This study suggests that combining metabolomics with traditional Chinese medicine diagnosis can reveal metabolic signatures for CHF syndrome subtypes. The plasma metabolites identified might be of special clinical relevance for subtypes of CHF, which could lead to further understanding of mechanisms involved and an improvement in personalized treatment for CHF.

The transcription activator-like (TAL) effector targets specific host promoter through its central DNA-binding domain, which comprises multiple tandem repeats (TALE repeats). Recent structural analyses revealed that the TALE repeats form a superhelical structure that tracks along the forward strand of the DNA duplex. Here, we demonstrate that TALE repeats specifically recognize a DNA-RNA hybrid where the DNA strand determines the binding specificity. The crystal structure of a designed TALE in complex with the DNA-RNA hybrid was determined at a resolution of 2.5 Å. Although TALE repeats are in direct contact with only the DNA strand, the phosphodiester backbone of the RNA strand is inaccessible by macromolecules such as RNases. Consistent with this observation, sequence-specific recognition of an HIV-derived DNA-RNA hybrid by an engineered TALE efficiently blocked RNase H-mediated degradation of the RNA strand. Our study broadens the utility of TALE repeats and suggests potential applications in processes involving DNA replication and retroviral infections.

Compact tension specimens were fabricated with Ti-6Al-4V titanium alloy by selective laser melting. Some specimens were heat treated and some were hot-isostatic pressed (HIPed). Half of these specimens in three conditions were polished. Fatigue crack growth (FCG) test was conducted to obtain FCG data, and to research into the effect of post-processes. The microstructure and fractography were observed to find possible reasons for FCG variaton. The results indicated that, FCG preformance of as-built SLM Ti-6Al-4V is inferior to conventional material due to the fine needle martensitic structure and large residual stress. Both heat treatment and hot-isostatic pressing lead to thicker o phase and more ß phase, diminsh or even eliminate the residual stress, and improve FCG performance signifcantly. FCG rates of heat treated and HIPed speicmens are comparable to those of Ti-6Al-4V fabricated by conventional techonology. When the crack length and stress intensity factor are larger than a certain value, surface polishing shows haldly any effect.

The key components in aircraft will be subjected to typical asymmetric loads in service,thus their fatigue behavior can be inevitably strongly affected by the mean stress effect. The modified Walker model employs the multiple-nonlinearfitting method to deal with fatigue test data under various stress ratios,by which the influence of material and maximum stress on mean stress effect can both be considered. Eighteen sets of fatigue test data from twelve kinds of aeronautical materials in various loading conditions were employed to validate the predict accuracy of modified Walker model,and the results were compared with other commonly used models. The study shows that the influence of maximum stress on mean stress effect varies with materials,while the prediction accuracy of the modified Walker model for each group of test data is better than that any other candidate models to varying degrees.

The fatigue characteristic of TC4 titanium alloy by selective laser melting（ SLM） with two different surface roughness is investigated. The detail fatigue rating（ DFR） values are achieved based on the fatigue tests. The fatigue fractography is observed by scanning electron microscope to find the reason for surface roughness modification. The results indicate that DFR value of as-built surface specimen is 235. 1 MPa and machined surface specimen is 283. 3 MPa. So the SLM TC4 specimen in machined surface has superior fatigue property. The surface roughness has a significant effect on the crack initiation site. The fatigue crack in as-built specimen initiates from surface. Fatigue crack in machined specimen initiates from inside to subsurface.The latter is flat and the former is relatively rough.

Based on the fatigue test of three-row parallel holes without prefabricated cracks,the law of multiple site damage（MSD） for multi-detail structures with similar stress levels was studied. In order to study the interference effect between the cracks in the MSD structure,the FRANC2 D/L was used to calculate and analyze the crack stress intensity factor of four cracking modes:main crack,equal-length double-sided crack,equal-length single-double crack and single-hole isometric crack. The calculation results show that the crack is mainly affected by the interference of the stress concentration of the cracked hole in the initial stage of crack propagation. The dimensionless stress intensity factors of the cracks are similar in the four modes. As the crack length increases,both the test and finite element results show that the interference between the cracks significantly accelerates the crack propagation rate.

This study aims to evaluate the FGH96 superalloy joints fabricated by inertia friction welding (IFW) in different welding parameters, such as initial rotational speed and axial friction pressure, where the moment of inertia remained constant. The microstructure and the width of the weld nugget zone (WNZ) were analyzed, and tensile property of joints was examined. The effect of welding parameters on high temperature tensile property of FGH96 joints was investigated. The results show that the joint presents a significant microstructure change across the faying interface, characterized by the very small uniform equiaxed grains of WNZ, coarse and fine grain coexistence of the thermo-mechanically affected zone (TMAZ). As the rotation speed increases, the tensile property remains constant. However, with increasing friction pressure, they show a substantial increase.The change tendency of the width of WNZ with welding parameters is in agreement with that of tensile property, which is related to the weld heat input and the plastic flow of the material. The high temperature tensile specimens are fractured in the WNZ. This is related to the complete γ′-phase dissolution which softens the joint and decreases the joint tensile property. Therefore, the post-weld heat treatments are necessary for IFW FGH96 superalloy in order to further improve the joint properties.

Ti-6 Al-4 V titanium alloy specimens were built using selective laser melting. Some specimens were heat treated and some were hot-isostatically pressed. Half of these specimens in three conditions were polished. Tensile test was conducted to research into the effect of heat treatment/hot-isostatic pressing and polish on the mechanical properties. The microstructure and fractography were observed using optical microscope and scanning electron microscope to find the reason for mechanical property modifications. The test results demonstrate that,after heat treatment or hot-isostatic pressing,the ultimate tensile strength of SLM Ti-6 Al-4 V is reduced significantly while the elongation is improved by around 50%. Polish results in the increase of yield and ultimate strength by about 30 MPa for hot-isostatic pressed specimens,but leads to no apparent improvement in mechanical properties for as-built and heat treated specimens.

Internal pressure is a severe cyclic load for fuselage structure, and it is important to investigate the fatigue and damage tolerance characters of fuselage panel under internal pressure. Boundary condition simulation of fuselage panel subjected to internal pressure load is challenging, and the quality of the simulation influences the range of transition area and even the stress distribution size in examining area. To investigate the stress distribution of fuselage panel subjected to internal pressure, a new test method is proposed. “D” jig is utilized to simulate the longitudinal boundary conditions of fuselage panel, and “Arch” connectors are utilized to simulate the circumferential boundary conditions. Airtight end-plate is utilized to simulate the end of the fuselage barrel. Test fixture and fuselage panel specimen are designed and manufactured according to the boundary simulation requirements. Tests are conducted based on the proposed method. The test results show that hoop stress and axial stress in transition area are much more lower than in the test area. Hoop stress, axial stress and normal displacement in the test area are consistent with theoretic results. The proposed test method settle for engineering precision requirements and provides reference for configuration-selection tests of fuselage panel subjected to internal pressure load.

In virtue of Detail Fatigue Rating method（DFR）, an optimization design method of aircraft plate-web beam structure against fatigue buckling is proposed based on genetic algorithm. After finite element analysis and experimental verification, an optimized model of structure life on fatigue buckling is built by engineering method, and the structure design solution in the condition of minimum mass is achieved with maximum fatigue life. The theoretical results illustrated that the life can excessively increase than that of the original beam. This technology will provide the design strategy of reducing aircraft mass and cost production for general aircraft structure.

Aiming at typical connection structure of the bolt holes errors on edge strip of front spar of central wing,this paper analyzes the fatigue property of the structure. The fatigue life of the structure is analyzed by means of structure durability analysis theory. The detail fatigue rating is worked out by finite element analysis and through experimental verification; this paper studies the changes of fatigue life and detail fatigue rating between structure with manufacturing errors and the original structure.Through theoretical and experimental analysis,this paper judges the validity of repair methods for the fastening holes error in the current aviation industry and provides theoretical and experiment data support for repairing methods.

Results from an experimental and analytical study of a curved stiffened aluminum panel subjected to combined internal pressure and axial tension loads are presented. The behaviors of the crack propagation and characteristics of the residual strength for fuselage panel are investigated. Stress intensity factors associated with different crack lengths are analyzed by using ANSYS software,and the crack propagation cycles are predicted. The residual strength curves are calculated based on the linear elastic fracture mechanics by comparison of experimental results. Analysis results agree well with the test results. Both results can provide the bases for the damage tolerance design and assessment of fuselage structure.

The test method of fuselage panel subjected to shear load is an important technique for aircraft structure strength research. A new shear test method is proposed based on the property of aircraft fuselage panel subjected to shear load. "D"jig and arch angle connectors is designed to simulate the circular structure of fuselage,and the shear stress is applied through the torsional form of single closed box structure,consisting of "D"jig and fuselage panel through hinge. A test panel and a set of fixtures were designed and manufactured,and validation test were conducted. Validation test verifies the validity and engineering feasibility of this method,and the stress distribution of panel in test is uniform as well as in a good agreement with theoretical analysis. In addition,this test method avoids to design a transition section and a loading section with the similar length of aircraft fuselage panel,and saves assembly work and test expenses. The stability test of the fuselage panel on civil aircraft adopts this new method at present.

First of all,stress analysis of lug under different loading angles was carried out. For the fatigue life analysis of lug under tension-compression loads,the compression load was treated equivalently,and the effective equivalent load factor λ was obtained. The fatigue load spectrum was equivalent to Pmax λPmin,and then the fatigue life of lug structure was obtained by the Detail Fatigue Rating（ DFR） method. Finally,the method was proved by the fatigue test of lug in 45° angles load,which proves that the method is practical in engineering.

Based on the dependence of fatigue crack growth（ FCG） threshold on stress ratio,a low-load-truncation method for FCG tests is proposed. The effects of FCG property,stress amplitude and stress ratio are considered by this method. FCG tests using middle tension（ M（ T）） specimens under a flight-by-flight spectrum and two truncated spectra were conducted. The difference between FCG lives under truncated spectra and those under baseline spectrum is less than 26%,but the test duration were shorten by 78% maximum. The test results indicate that the proposed low-load-truncation method can shorten FCG test period effectively without changing the failure mode or changing the FCG life irrationally.

Based on years’ experience in fracture toughness tests,the matters need attention for KRcurve and fracture toughness determination using thin compact tension（ C（ T）） specimen were studied.The KRcurve and fracture toughness of LY12 CZ alloy and friction stir welded joints were determined according to proposed test method.The microstructures of FSW joint were also observed utilizing metalloscope.The test result demonstrates that the fracture toughness of friction stir welded LY12 CZ alloy is higher than that of the parent alloy,because the weld nugget presents fine recrystallized structure.It is also found that the fracture toughnesses with crack perpendicular to rolling direction are higher than those with crack parallel to rolling direction for both welded and parent alloy.In addition,the test result indicates that the fracture toughness of C（ T） specimen is related to inplane dimension,and that the fracture toughness increases with the increase of in-plane dimension.

A new subsection-loading method has been used for solving question that was taken for aircraft structure cracking growth testing（ CGT） in a long time.Based on technology of low load cut-off,the random loading spectrum used in CGT,associated with the stress intensity factor in crack tip of specimens,was investigated.Furthermore,Testing verification of panel specimen has been completed.The testing result showed that pre-simplification agrees with subsection of the random loading spectrum,and application of the method can reduce the time of CGT reliably（ time reducing by 27% in the testing）.Finally,it can be concluded that the method can directly be applied for CGT of fuselage panel and other aircraft structures.

The test method of fuselage panel subjected to internal pressure load is an important technique for aircraft structure strength research.The constraint simulation technique for the curved and straight boundaries of fuselage panel was studied based on boundary requirements.A test method using "D"jig to simulate the straight boundary conditions and airproof end-plate to simulate the curved boundary conditions of fuselage panels were proposed.A test panel and a set of fixtures were designed and manufactured,and validation tests were conducted.Measured stresses in test are reasonably distributed and are consistent with theoretic result.The proposed test method is proven to be proper and valid,and it provides reference for configuration-selection tests of fuselage panel subjected to internal pressure load.

A new species of the genus Hebius Thompson, 1913 is described from Yingjiang County, Dehong Dai and Jingpo Autonomous Prefecture, Yunnan Province, China, based on molecular and morphological evidence. It can be distinguished from its congeners by the following set of characters: (1) dorsal scale rows 19–17–17, feebly keeled; (2) ventrals 146–151; (3) nasal complete, nostril in the middle of the nasal; (4) supralabials 9, the fourth to sixth in contact with the eye; (5) infralabials 10–11, the first 5 touching the first pair of chin shields; (6) preoculars 2; (7) postoculars 3; (8) temporals 3, arranged in two rows (1+2); (9) maxillary teeth 31, the last 4 slightly enlarged, without diastema; (10) tail comparatively long, TAL/TL ratio 0.334 in the male; (11) dorsolateral series of irregular orange or ochre yellow blotches, extending from the neck to the posterior part of the tail; and (12) venter pale orange, tips of ventrals with subrectangular black blotches. All Hebius specimens were strongly recovered as monophyletic, in which Hebius taronensis (Smith, 1940) and Hebius venningi (Wall, 1910) were monophyletic as sister to the Yingjiang County specimens. According to the p‐distance of cytochrome b, the new species differs from its congeners by 9.7–15.4%.

IntroductionThe study aimed to evaluate the effects of Pleurotus Spent Mushroom Substrate (P.SMS) on the rumen microbiota, encompassing bacteria and fungi, as well as their interactions in Hu sheep.MethodsA total of forty-five 3-month-old Hu sheep were randomly assigned to five groups. Each group was fed diets in which whole-plant corn silage (WPCS) was substituted with P.SMS at varying levels: 0% (CON), 5% (PSMS5), 10% (PSMS10), 15% (PSMS15), or 20% (PSMS20).ResultsThe results indicated that higher proportions of P.SMS during the experimental period might have a detrimental effect on feed utilization efficiency, kidney function, and blood oxygen-carrying capacity. Notably, moderate levels of P.SMS, specifically below 15%, were associated with improvements in rumen NH3-N levels and absorption capacity. The results indicated that (1) PSMS20 exhibited a significantly higher feed-to-gain ratio compared to CON (P

Abstract Background Folic acid (FA) supplementation is associated with a lower risk of the neural tube and heart defects and is recommended for women of childbearing age. Although there are detailed recommendations, differences in the initiation time and duration of FA supplementation remain poorly studied. Methods A multicentre prospective study of 17,713 women was conducted. The incidence of congenital malformations in women taking a recommended dosage (e.g. 0.4 or 0.8 mg/day) of FA was compared with that in women without supplementation. The predicted probability of malformations by the initiation time and duration of FA use was estimated to determine optimal options. Results Periconceptional FA supplementation was associated with a lower and insignificant risk of congenital malformations (1.59% vs. 2.37%; odds ratio [OR] 0.69; 95% confidence interval [CI]: 0.44–1.08), heart defects (3.8 vs. 8.0 per 1000 infants; OR, 0.47; 0.21–1.02), and neural tube defects (7.0 vs. 11.5 per 10,000 infants; OR, 0.64; 0.08–5.15). FA use after pregnancy provided greater protection against total malformations. Statistically significant associations were found in women who initiated FA supplementation in the first month of gestation (OR, 0.55; 95% CI: 0.33–0.91) and in those who supplemented for 1 to 2 months (OR, 0.59; 95% CI: 0.36–0.98). Similar results were found for heart defects. The optimal initiation time was 1.5 (optimal range: 1.1 to 1.9) months before pregnancy and a duration of 4.0 (3.7 to 4.4) months was reasonable to achieve the lowest risk of congenital malformations. Heart defect prevention required an earlier initiation (2.2 vs. 1.1 months before pregnancy) and a longer duration (4.7 vs. 3.7 months) than the prevention of other malformations. Conclusions The timely initiation of FA supplementation for gestation was associated with a decreased risk of congenital malformations, which was mainly attributed to its protection against heart defects. The initiation of FA supplementation 1.5 months before conception with a duration of 4 months is the preferred option for congenital malformation prevention. Trial registration Chictr.org.cn identifier: ChiCTR-SOC-17010976.

Abstract Pervasive environmental contamination due to the uncontrolled dispersal of 2,4‐dinitrotoluene (2,4‐DNT) represents a substantial global health risk, demanding urgent intervention for the removal of this detrimental compound from affected sites and the promotion of ecological restoration. Conventional methodologies, however, are energy‐intensive, susceptible to secondary pollution, and may inadvertently increase carbon emissions. In this study, a 2,4‐DNT degradation module is designed, assembled, and validated in rice plants. Consequently, the modified rice plants acquire the ability to counteract the phytotoxicity of 2,4‐DNT. The most significant finding of this study is that these modified rice plants can completely degrade 2,4‐DNT into innocuous substances and subsequently introduce them into the tricarboxylic acid cycle. Further, research reveals that the modified rice plants enable the rapid phytoremediation of 2,4‐DNT‐contaminated soil. This innovative, eco‐friendly phytoremediation approach for dinitrotoluene‐contaminated soil and water demonstrates significant potential across diverse regions, substantially contributing to carbon neutrality and sustainable development objectives by repurposing carbon and energy from organic contaminants.

2,4-Dinitrotoluene (2,4-DNT) as a common industrial waste has been massively discharged into the environment with industrial wastewater. Due to its refractory degradation, high toxicity, and bioaccumulation, 2,4-DNT pollution has become increasingly serious. Compared with the currently available physical and chemical methods, in situ bioremediation is considered as an economical and environmentally friendly approach to remove toxic compounds from contaminated environment. In this study, we relocated a complete degradation pathway of 2,4-DNT into Escherichia coli to degrade 2,4-DNT completely. Eight genes from Burkholderia sp. strain were re-synthesized by PCR-based two-step DNA synthesis method and introduced into E. coli. Degradation experiments revealed that the transformant was able to degrade 2,4-DNT completely in 12 h when the 2,4-DNT concentration reached 3 mM. The organic acids in the tricarboxylic acid cycle were detected to prove the degradation of 2,4-DNT through the artificial degradation pathway. The results proved that 2,4-DNT could be completely degraded by the engineered bacteria. In this study, the complete degradation pathway of 2,4-DNT was constructed in E. coli for the first time using synthetic biology techniques. This research provides theoretical and experimental bases for the actual treatment of 2,4-DNT, and lays a technical foundation for the bioremediation of organic pollutants.

Abstract Background Production of vitamin C has been traditionally based on the Reichstein process and the two-step process. However, the two processes share a common disadvantage: vitamin C cannot be directly synthesized from D-glucose. Therefore, significant effort has been made to develop a one-step vitamin C fermentation process. While, 2-KLG, not vitamin C, is synthesized from nearly all current one-step fermentation processes. Vitamin C is naturally synthesized from glucose in Arabidopsis thaliana via a ten-step reaction pathway that is encoded by ten genes. The main objective of this study was to directly produce vitamin C from D-glucose in Escherichia coli by expression of the genes from the A. thaliana vitamin C biosynthetic pathway. Results Therefore, the ten genes of whole vitamin C synthesis pathway of A. thaliana were chemically synthesized, and an engineered strain harboring these genes was constructed in this study. The direct production of vitamin C from D-glucose based on one-step fermentation was achieved using this engineered strain and at least 1.53 mg/L vitamin C was produced in shaking flasks. Conclusions The study demonstrates the feasibility of one-step fermentation for the production of vitamin C from D-glucose. Importantly, the one-step process has significant advantages compared with the currently used fermentation process: it can save multiple physical and chemical steps needed to convert D-glucose to D-sorbitol; it also does not involve the associated down-streaming steps required to convert 2-KLG into vitamin C.

Recent paleobotanical investigations in Vietnam provide a good opportunity to improve our understanding of the biodiversity and paleoclimatic conditions in the geological past of Southeast Asia. Palms (Arecaceae) are a diverse family of typical thermophilous plants with a relatively low tolerance for freezing. In this study, we describe well-preserved fossil palm leaves from the Oligocene Dong Ho Formation of Hoanh Bo Basin, northern Vietnam. Characters of the fossil leaves, such as a fan-shaped costapalmate lamina, an unarmed petiole, a costa slightly enlarged at the base that then tapers distally into the blade, and well-preserved amphistomatic leaves with cuticles, suggest that they represent a new fossil species, which we herein designate Sabalites colaniae A. Song, T. Su, T. V. Do et Z.K. Zhou sp. nov. Together with other paleontological and palaeoclimatic evidence, we conclude that a warm climate prevailed in northern Vietnam and nearby areas during the Oligocene.

The marine environment is a harsh corrosive one for many materials. Marine corrosion will seriously reduce the service life of the material, damage the function of the material, and cause a serious waste of resource. In marine engineering, steel and concrete materials are the most widely used. Among them, wharf steel pipe piles are very important marine engineering facilities, and their corrosion conditions have a great impact on the safe use for marine facilities. In this paper, the corrosion status , anti-corrosive technologies and their application effect of some wharf steel pipe piles at home and abroad were investigated. Besides, the effective protection measures were put forward.

This work examined the linear instability of a two-dimensional liquid film on an oscillating plane theoretically in the presence of a static electric field perpendicular to the plane. The liquid was considered to be viscous and perfectly conducting, while the gas was considered to be viscous and dielectric. The viscous potential theory and Floquet theory were adopted to obtain the dispersion equation. The influences of electric field intensity, forcing amplitude, forcing frequency, and viscosity were obtained. The results showed that with there is more than one instability region with a non-zero forcing amplitude. The first instability region is called inherent instability, which is due to the electric force overcoming the viscous dissipation, surface tension, and gravity, while the other regions are due to the parametric instability induced by the oscillating plane, forming famous Faraday waves. It was found that increasing the forcing amplitude stabilizes the inherent instability but has a destabilizing impact on Faraday waves. In addition, the increase in the electric field intensity and forcing frequency enhances the inherent instability but has a complex impact on the Faraday waves, depending on the intensity of the viscous dissipation, which is approximately proportional to the square of the wavenumber.

China has the world's largest sheep flock and the largest producer of sheep meat by far. However, the nutrient requirements have not been systemically studied and there is a lack of knowledge of nutrient requirement for meat-type sheep in China. Since 2008, the nutrient requirements of meat-type sheep in China has been systematically investigated. In this review, we introduced the history of studies of nutrient requirements of meat-type sheep in China, summarized the recent advances in nutrient requirements of meat-type sheep, and highlighted the future directions of researches on nutrient requirements of meat-type sheep in China.

Blood-brain barrier (BBB) disruption underlies the vasogenic edema and neuronal cell death induced by acute ischemic stroke. Reducing this disruption has therapeutic potential. Transcranial focused ultrasound stimulation has shown neuromodulatory and neuroprotective effects in various brain diseases including ischemic stroke. Ultrasound stimulation can reduce inflammation and promote angiogenesis and neural circuit remodeling. However, its effect on the BBB in the acute phase of ischemic stroke is unknown. In this study of mice subjected to middle cerebral artery occlusion for 90 minutes, low-intensity low-frequency (0.5 MHz) transcranial focused ultrasound stimulation was applied 2, 4, and 8 hours after occlusion. Ultrasound stimulation reduced edema volume, improved neurobehavioral outcomes, improved BBB integrity (enhanced tight junction protein ZO-1 expression and reduced IgG leakage), and reduced secretion of the inflammatory factors tumor necrosis factor-α and activation of matrix metalloproteinase-9 in the ischemic brain. Our results show that low-intensity ultrasound stimulation attenuated BBB disruption and edema formation, which suggests it may have therapeutic use in ischemic brain disease as a protector of BBB integrity.

BackgroundExcision repair cross-complementing group 1 (ERCC1) was considered a potential candidate gene for ischemic stroke, and its polymorphisms might be associated with the susceptibility to ischemic stroke.MethodsA total of 513 patients with ischemic stroke and 550 control subjects were recruited. The expression levels of ERCC1 messenger RNA (mRNA) in peripheral blood mononuclear cells and its protein in plasma were detected by quantitative real-time PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Rs3212986 polymorphism of ERCC1 was detected by PCR-restriction fragment length polymorphism (RFLP-PCR) and was confirmed by sequencing. The association between the ERCC1 rs3212986 polymorphism or its expression and ischemic stroke was further analyzed.ResultsThe ERCC1 mRNA level in patients with ischemic stroke was lower than that in the control group (P < 0.05). However, the ERCC1 protein level in patients with ischemic stroke was higher than that in the control group (P < 0.05). The A allele of rs3212986 was associated with increased ischemic stroke risk (OR = 1.287, 95% CI = 1.076–1.540, P = 0.006). The association between rs3212986 polymorphism and ischemic stroke susceptibility was found in both recessive (OR = 2.638, 95% CI = 1.744–3.989, P < 0.001) and additive models (OR = 1.309, 95% CI = 1.028–1.667, P = 0.031), respectively. Similar results were obtained in the recessive model (OR = 2.015, 95% CI = 1.087–3.704, P = 0.026) after adjusting for demographic information and other variables. Additionally, the level of ERCC1 mRNA in the CC/CA genotype was higher than that in the AA genotype (P < 0.05).ConclusionIt was suggested that the ERCC1 rs3212986 polymorphism was associated with ischemic stroke susceptibility in a Chinese Han population and that an A allele of rs3212986 was related to increased ischemic stroke risk. The altered ERCC1 expression level caused by the rs3212986 polymorphism might participate in the pathophysiological process of ischemic stroke.

Abstract p-Nitrophenol (PNP) is an important environmental pollutant and can causes significant environmental and health risks. Compared with the traditional methods, biodegradation is a useful one to completely remove the harmful pollutants from the environment. Here, an engineered strain was first constructed by introducing PNP biodegradation pathway via the hydroquinone (HQ) pathway into Escherichia coli. In the engineered strain BL-PNP, PNP was completely degraded to β-ketoadipate and subsequently enter the metabolites of multiple anabolic pathways. The high tolerance and rapid degradation ability to PNP enable the engineered strain to have the potential to degrade toxic substances. The engineered strain created in this study can be used as a functional strain for bioremediation of PNP and potential toxic intermediates, and the method of assembling aromatic hydrocarbons metabolic pathway can be used to eradicate nitroaromatic pollutants in the environment.