Analyzing the Effect of Particle Shape on Deformation Mechanism during Cutting Simulation of SiC P/Al Composites.

To analyze the effect of particle shape on deformational behavior in the cutting simulation process for metal matrix composites (MMCs), two 2D mesoscopic-based finite element (FE) models reinforced with randomly distributed circular and irregular polygonal particles were developed. Different material properties (metal matrix phase, particle reinforced phase) and the properties of the particle-matrix interface were comprehensively considered in the proposed FE model. Systematic cutting experiments were conducted to compare the differences between two modeling approaches with respect to particle fracture, chip formation, cutting force and surface integrity. The results show that the irregular polygonal particle model is closer to the microstructure of MMCs, and is better able to reflect the deformation behavior of particles. The simulation model with irregular polygonal particles is even able to capture more details of the impact caused by particles, reflecting variations in the cutting force in the actual cutting process. The initiation and propagation of microcracks is mainly determined on the basis of particle geometry and further affects chip formation. Both models are able to correctly reflect surface defects, but the irregular polygonal particle model provides a more comprehensive prediction for the subsurface damage of MMCs.

The Impact of the COVID-19 Pandemic and the Importance of Telemedicine in Managing Acute ST Segment Elevation Myocardial Infarction Patients: Preliminary Experience and Literature Review.

The coronavirus disease 2019 (COVID-19), which is caused by a novel coronavirus (SARS-COV-2), has compromised health care systems and normal management of patients with cardiovascular diseases [1-3]. Patients with non-communicable diseases, including acute myocardial infarction (AMI) are vulnerable to this stress [4, 5]. Acute ST segment elevation myocardial infarction (STEMI), the most critical type of AMI, is associated with high mortality even with modern medicine [6-8]. Timely reperfusion therapy is critical for STEMI patients because a short ischemia time is associated with better clinical outcomes and lower acute and long -term mortality [9-12]. The COVID-19 pandemic placed the management of STEMI patients in a difficult situation due to the need to balance timely reperfusion therapy and maintaining strict infection control practices [13, 14]. Telemedicine, which is used to deliver health care services using information or communication technology, provides an opportunity to carry out the evaluation, diagnosis, and even monitor the patients after discharge when social distancing is needed [15]. In this article, we reported our preliminary experience with the usefulness of telemedicine in managing STEMI patients during the COVID-19 pandemic. We also provided a review of this topic.

[Discuss about Key Issues of Dual Energy X-ray Absorptiometry Evaluation].

The Dual energy X-ray absorptiometry is the most commonly used for measuring bone mineral density. This method involves core clinical functions, phantom and database. This article discusses the three key issues of dual energy X-ray absorptiometry evaluation, including core clinical functions, phantom and database. This article aims at helping manufacturers to scientifically carry out relevant processes during research and development and also manufacturers may refer to this article when they apply for registration.

Multi-omics Comparative Analysis of Streptomyces Mutants Obtained by Iterative Atmosphere and Room-Temperature Plasma Mutagenesis.

Sponges, the most primitive multicellular animals, contain a large number of unique microbial communities. Sponge-associated microorganisms, particularly actinomyces, have the potential to produce diverse active natural products. However, a large number of silent secondary metabolic gene clusters have failed to be revived under laboratory culture conditions. In this study, iterative atmospheric room-temperature plasma. (ARTP) mutagenesis coupled with multi-omics conjoint analysis was adopted to activate the inactive wild Streptomyces strain. The desirable exposure time employed in this study was 75 s to obtain the appropriate lethality rate (94%) and mutation positive rate (40.94%). After three iterations of ARTP mutagenesis, the proportion of mutants exhibiting antibacterial activities significantly increased by 75%. Transcriptome analysis further demonstrated that the differential gene expression levels of encoding type I lasso peptide aborycin had a significant upward trend in active mutants compared with wild-type strains, which was confirmed by LC-MS results with a relative molecular mass of 1082.43 ([M + 2H]2+ at m/z = 2164.86). Moreover, metabolome comparative analysis of the mutant and wild-type strains showed that four spectra or mass peaks presented obvious differences in terms of the total ion count or extracting ion current profiles with each peak corresponding to a specific compound exhibiting moderate antibacterial activity against Gram-positive indicators. Taken together, our data suggest that the ARTP treatment method coupled with multi-omics profiling analysis could be used to estimate the valid active molecules of metabolites from microbial crudes without requiring a time-consuming isolation process.

[Combined resection of preseptal fat and partial retro-orbicularis oculus fat: a method for refractory upper eyelid heaviness correction].

UNLABELLED: OBJECTIVE To investigate an operative method of combined resection of preseptal fat: and partial retro-orbicularis oculus fat (ROOF) for correction of upper eyelid heaviness, and evaluate the efficacy and safety of the method. METHODS: Preseptal fat lies widely under the orbicularis oculi in the upper eyelid, and retro-orbicularis oculus fat (ROOF) lies in the lateral supraorbital area. Combined resection of preseptal fat and partial ROOF was performed in patients selected by examination. The efficacy and safety were evaluated by follow-up study. RESULTS: From May 2011 to July 2013, 38 selected patients received the treatment with 3 months to 28 months follow up. The heaviness of upper eyelid improved in all cases. One patient developed postoperative hematoma, and another patient had a transient numbness over the lateral upper brow region. 37 patients were satisfied with the result. CONCLUSIONS: Combined resection of preseptal fat and partial ROOF was effective in reducing the heaviness of upper eyelid, without major complications. The operative method should be an important adjunct for selected patients undergoing blepharoplasty.