Advances on in situ TEM mechanical testing techniques: a retrospective and perspective view

Over the past few decades, in situ transmission electron microscopy (TEM) has emerged as a powerful experimental technique for materials design and characterization. It offers unparalleled dynamic details of materials deformation under mechanical stimuli, providing fundamental insights into their deformation and failure mechanisms for various materials. In this review, we summarize recent advances on in situ TEM mechanical characterization techniques, including classical tension holders, nanoindentation holders, MEMS devices, thermal bimetallic-based techniques, and nanomanipulation techniques. The advantages and limitations of in situ TEM tests are also discussed. To provide a broader perspective, the article highlights promising opportunities for in situ TEM mechanical testing studies in characterization-processing-manufacturing based on nanomanipulation, ultrafast TEM, electron beam irradiation environmental conditions, data-driven machine learning, and integrated experimental and simulation characterization. This article aims to provide a comprehensive understanding of in situ TEM-based mechanical characterization techniques to promote the development of novel materials with improved mechanical properties for various applications

Molecular epidemiology of measles viruses in China, 1995–2003

This report describes the genetic characterization of 297 wild-type measles viruses that were isolated in 24 provinces of China between 1995 and 2003. Phylogenetic analysis of the N gene sequences showed that all of the isolates belonged to genotype H1 except 3 isolates, which were genotype A. The nucleotide sequence and predicted amino acid homologies of the 294-genotype H1 strains were 94.7%–100% and 93.3%–100%, respectively. The genotype H1 isolates were divided into 2 clusters, which differed by approximately 2.9% at the nucleotide level. Viruses from both clusters were distributed throughout China with no apparent geographic restriction and multiple co-circulating lineages were present in many provinces. Even though other measles genotypes have been detected in countries that border China, this report shows that genotype H1 is widely distributed throughout the country and that China has a single, endemic genotype. This important baseline data will help to monitor the progress of measles control in China

RhoA-Derived Peptide Dimers Share Mechanistic Properties with Other Polyanionic Inhibitors of Respiratory Syncytial Virus (RSV), Including Disruption of Viral Attachment and Dependence on RSV G

Large polyanionic molecules, such as sulfated polysaccharides (including soluble heparin and dextran sulfate), synthetic polyanionic polymers, and negatively charged proteins, have been shown to broadly inhibit several enveloped viruses. We recently reported the antiviral activity of a peptide derived from amino acids 77 to 95 of a potential binding partner of respiratory syncytial virus F protein (RSV F), the GTPase RhoA. A subsequent study with a truncated peptide (amino acids 80 to 94) revealed that optimal antiviral activity required dimerization via intermolecular disulfide bonds. We report here that the net negative charge of this peptide is also a determining factor for its antiviral activity and that it, like other polyanions, inhibits virus attachment. In a flow cytometry-based binding assay, peptide 80-94, heparin, and dextran sulfate inhibited the attachment of virus to cells at 4°C at the same effective concentrations at which they prevent viral infectivity. Interestingly, time-of-addition experiments revealed that peptide 80-94 and soluble heparin were also able to inhibit the infectivity of a virus that had been prebound to cells at 4°C, as had previously been shown for dextran sulfate, suggesting a potential role for postattachment effects of polyanions on RSV entry. Neutralization experiments with recombinant viruses showed that the antiviral activities of peptide 80-94 and dextran sulfate were diminished in the absence of the RSV attachment glycoprotein (G). Taken together, these data indicate that the antiviral activity of RhoA-derived peptides is functionally similar to that of other polyanions, is dependent on RSV G, and does not specifically relate to a protein-protein interaction between F and RhoA

Performance Study on a Single-Screw Expander for a Small-Scale Pressure Recovery System

A single-screw expander with 195 mm diameter is developed to recover pressure energy in letdown stations. An experiment system is established using compressed air as a working fluid instead of natural gas. Experiments are conducted via measurements for important parameters, such as inlet and outlet temperature and pressure, volume flow rate and power output. The influence of inlet pressure and rotational speed on the performance are also analyzed. Results indicate that the single-screw expander achieved good output characteristics, in which 2800 rpm is considered the best working speed. The maximum volumetric efficiency, isentropic efficiency, overall efficiency, and the lowest air-consumption are 51.1 kW, 83.5%, 66.4%, 62.2%, and 44.1 kg/(kW·h), respectively. If a single-screw expander is adopted in a pressure energy recovery system applied in a certain domestic natural gas letdown station, the isentropic efficiency of the single-screw expander and overall efficiency of the system are found to be 66.4% and 62.2%, respectively. Then the system performances are predicted, in which the lowest methane consumption is 27.3 kg/(kW·h). The installed capacity is estimated as 204.7 kW, and the annual power generation is 43.3 MWh. In the next stage, a pressure energy recovery demonstration project that recycles natural gas will be established within China, with the single-screw expander serving as the power machine

Transformation plan for differentiated lightning protection of power supply lines in a mountainous oil transmission station

In order to ensure the reliable operation of oil transmission stations and improve the lightning protection performance of their power supply lines, the lightning accidents occurred to power supply lines in the Anshun Station in the southern mountainous area of China during 2018 to 2020 were counted by category, and comprehensive analysis was performed for the lightning accidents. On this basis, the poles and towers requiring transformation for lightning protection were determined by considering the four influencing factors of line corridor, i.e., ground flash density, topography, grounding resistance of poles and towers, and lightning withstand level. In view of the lightning protection measures of improving the insulation level, reducing the grounding resistance, and installing lightning arresters, analysis was conducted for the poles and towers one by one, and transformation measures for differentiated lightning protection were put forward on the basis of ensuring the lightning protection capability, with reference to the on-site construction of the lines and the economic conditions of line transformation. Upon completion of the line transformation, the trip rate and equipment damage rate caused by lightning are significantly reduced, which proves the scientificity and effectiveness of the transformation plan

A novel large deletion of the CYLD

Abstract Background CYLD cutaneous syndrome (CCS; syn. Brooke‐Spiegler syndrome) is a rare autosomal dominant hereditary disease characterized by multiple adnexal skin tumors including cylindromas, spiradenomas, and trichoepitheliomas. More than 100 germline mutations of the cylindromatosis (CYLD) gene have been reported in CCS and most of them are frameshift mutations or small alterations. Methods We identified a large, three‐generation Chinese family with CCS, which consisted of 18 living family members, including six affected individuals. To explore the molecular biology of this family, we carried out targeted next‐generation sequencing and Affymetrix CytoScan HD SNP array to analyze the mutation in the CYLD gene. Results A novel large deletion mutation, NC_000016.9:g.(50826498_50827517)_(50963389‐50967346)del was found in the proband of this family. This deletion results in the loss of a nearly 140 kb fragment of the CYLD gene, spanning exons 17 ~ 20, which represent the coding regions of the ubiquitin‐specific protease domain. Further quantitative polymerase chain reaction proved that all patients and two proband‐related family members carried this large deletion. Conclusions Our study expands the types of mutations in CCS and will undoubtedly provide valuable information for genetic counseling for families affected by the condition

Improved Electrogeometric Model Suitable for EHV and UHV Transmission Lines Developed through Breakdown Testing for Long Air Gaps

As a type of engineering model used for solving lightning-shielding problems, the electrogeometric model has been widely used for assessing lightning-shielding failure in high-voltage and extra-high-voltage transmission lines. However, with the increase of voltage levels in ultra-high-voltage lines and the growth of the air gap, the results previously yielded by the electrogeometric model are no longer consistent with those observed. Therefore, this study corrected the equation for the relationship between lightning current and striking distance, by using data on a negative polarity 50% discharge voltage from the rod-rod gap −20/2500 μs switching impulse test wherein an air gap of up to 10 m was first tested. Subsequently, the return stroke velocity distribution observed by Idone was newly applied. In addition, the correction factor for the ground was corrected in this study. Thus, an improved electrogeometric model for application in EHV and UHV transmission lines is proposed in this paper. By employing the improved electrogeometric model to calculate the frequency of lightning strikes of 500 and 1000 kV transmission lines in Japan and a 1000 kV transmission line in China, we found that the results calculated using the improved electrogeometric model were closer to the actual observations in Japan than was the original electrogeometric model. The improved electrogeometric model provides a more reliable foundation for lightning-shielding design of extra-high-voltage and ultra-high-voltage transmission lines