Acoustic transmission enhancement through a periodically-structured stiff plate without any opening

We report both experimentally and theoretically that the enhanced acoustic transmission can occur in the subwavelength region through a thin but stiff structured-plate without any opening. This exotic acoustic phenomenon is essentially distinct from the previous related studies originated from, either collectively or individually, the interaction of the incident wave with openings in previous structures. It is attributed to the structure-induced resonant excitation of the non-leaky Lamb modes that exist intrinsically in the uniform elastic plate. Our finding should have impact on ultrasonic applications.Comment: 11 pages, 4 figure

Liver Toxicity of Rare Ginsenosides in Rats after 13 Weeks of Oral Exposure

Objective: This study aims to evaluate the hepatotoxicity of rare ginsenosides in rats after 90 days of oral administration using heat-transformed rare ginsenosides as the primary material. Methods: A total of 48 male and female rats were randomly assigned into four groups: High-dose rare ginsenosides (600 mg/kg), medium-dose rare ginsenosides (200 mg/kg), low-dose rare ginsenosides (60 mg/kg), and a blank control group. After 90 days of oral gavage treatment, ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) was employed for metabolomic analysis of rat serum and flow cytometry analysis of liver apoptosis to evaluate the potential liver damage comprehensively in rats. Results: A significant difference in hepatocyte apoptotic rate was observed between the high-dose group and the control group in both male and female rats (P0.05). However, 23 differential metabolites, such as histidine, glutamate, proline and arginine were identified in the serum of female rats in the high-dose group, affecting the histidine and urea cycle metabolic pathways and causing hyperammonemia and liver damage. Ten differential metabolites affecting the alpha-linolenic acid and linoleic acid metabolic pathways were found in male rats, such as linoleic acid and arachidonic acid. High concentrations of arachidonic acid showed inflammatory and toxic effects, which could be absorbed into the portal vein system through blood and cause liver damage. Conclusion: High-dose rare ginsenosides mainly cause slight liver damage in male and female rats mainly due to the changes of histidine, α-linolenic acid and linoleic acid metabolic pathways. Hence, no adverse liver effects were observed at doses less than 200 mg/kg in both male and female rats

Dissecting pulmonary fibroblasts heterogeneity in lung development, health and diseases

Lung fibroblasts are the major components in the connective tissue of the pulmonary interstitium and play essential roles in the developing of postnatal lung, synthesizing the extracellular matrix and maintaining the integrity of the lung architecture. Fibroblasts are activated in various disease conditions and exhibit functional heterogeneities according to their origin, spatial location, activated state and microenvironment. In recent years, advances in technology have enabled researchers to identify fibroblast subpopulations in both mouse and human. Here, we discuss pulmonary fibroblast heterogeneity, focusing on the developing, healthy and pathological lung conditions. We firstly review the expression profiles of fibroblasts during lung development, and then consider fibroblast diversity according to different anatomical sites of lung architecture. Subsequently, we discuss fibroblast heterogeneity in genetic lineage. Finally, we focus on how fibroblast heterogeneity may shed light on different pathological lung conditions such as fibrotic diseases, infectious diseases including COVID-19, and lung cancers. We emphasize the importance of comparative studies to illuminate the overlapping characteristics, expression profiles and signaling pathways of the fibroblast subpopulations across disease conditions, a better characterization of the functional complexity rather than the expression of a particular gene may have important therapeutic applications

A Heterogeneous Gold(I)-Catalyzed [2 + 2 + 1] Annulation of Terminal Alkynes, Nitriles, and Oxygen Atoms Leading to 2,5-Disubstituted Oxazoles

The first heterogeneous gold­(I)-catalyzed [2 + 2 + 1] annulation of terminal alkynes, nitriles, and oxygen atoms has been achieved by using an MCM-41-immobilized phosphine–gold­(I) complex as catalyst and 8-methylquinoline <i>N</i>-oxide as oxidant under mild conditions, yielding a variety of 2,5-disubstituted oxazoles in good to excellent yields with broad substrate scope. The new heterogeneous gold­(I) catalyst can easily be recovered by simple filtration of the reaction solution and recycled for at least eight times without significant loss of activity

Fabrication and mechanical behavior of 2D-Cf/TaxHf1−xC–SiC composites by a low-temperature and highly-efficient route

Cf/TaxHf1−xC–SiC composites are ideal thermal structural materials for service under extreme conditions of hypersonic vehicles. However, how to synthesize TaxHf1-xC powders and efficiently fabricate Cf/TaxHf1-xC–SiC composites still faces some challenges. Furthermore, mechanical properties and thermophysical properties of TaxHf1−xC vary with the composition, but not monotonically. In-depth analysis of mechanical behaviors of the Cf/TaxHf1−xC–SiC composites is extremely important for their development and applications. In this study, the TaxHf1−xC powders (x = 0.2, 0.5, 0.8) were successfully synthesized via solid solution of TaC and HfC at a relatively low temperature of 1800 ℃, with a small amount of Si as an additive. Subsequently, the efficient fabrication of 2D-Cf/TaxHf1–xC–SiC composites was achieved by slurry impregnation and lamination (SIL) combined with precursor infiltration and pyrolysis (PIP). In addition, the mechanical behavior of the composites was investigated systematically. It is demonstrated that the composites present remarkable non-brittle fractures, including a large number of fiber pull out and interphase debonding. Also, the fracture failure involves a complex process of microcrack generation and propagation, matrix cracking, and layer fracture. Moreover, the interfacial bonding between the fibers and the matrix is enhanced as the Ta∶Hf ratio decreases from 4∶1 to 1∶4. As a result, Cf/Ta0.2Hf0.8C–SiC composites exhibit exceptional flexural strength of 437±19 MPa, improved by 46% compared with Cf/Ta0.8Hf0.2C–SiC (299±19 MPa). This study provides a new perception of design and fabrication of ultra-high-temperature ceramic (UHTC) matrix composites with high performance

A new machine-learning method to prognosticate paraquat poisoned patients by combining coagulation, liver, and kidney indices

<div><p>The prognosis of paraquat (PQ) poisoning is highly correlated to plasma PQ concentration, which has been identified as the most important index in PQ poisoning. This study investigated the predictive value of coagulation, liver, and kidney indices in prognosticating PQ-poisoning patients, when aligned with plasma PQ concentrations. Coagulation, liver, and kidney indices were first analyzed by variance analysis, receiver operating characteristic curves, and Fisher discriminant analysis. Then, a new, intelligent, machine learning-based system was established to effectively provide prognostic analysis of PQ-poisoning patients based on a combination of the aforementioned indices. In the proposed system, an enhanced extreme learning machine wrapped with a grey wolf-optimization strategy was developed to predict the risk status from a pool of 103 patients (56 males and 47 females); of these, 52 subjects were deceased and 51 alive. The proposed method was rigorously evaluated against this real-life dataset, in terms of accuracy, Matthews correlation coefficients, sensitivity, and specificity. Additionally, the feature selection was investigated to identify correlating factors for risk status. The results demonstrated that there were significant differences in the coagulation, liver, and kidney indices between deceased and surviving subjects (<i>p</i><0.05). Aspartate aminotransferase, prothrombin time, prothrombin activity, total bilirubin, direct bilirubin, indirect bilirubin, alanine aminotransferase, urea nitrogen, and creatinine were the most highly correlated indices in PQ poisoning and showed statistical significance (<i>p</i><0.05) in predicting PQ-poisoning prognoses. According to the feature selection, the most important correlated indices were found to be associated with aspartate aminotransferase, the aspartate aminotransferase to alanine ratio, creatinine, prothrombin time, and prothrombin activity. The method proposed here showed excellent results that were better than that produced based on blood-PQ concentration alone. These promising results indicated that the combination of these indices can provide a new avenue for prognosticating the outcome of PQ poisoning.</p></div