Laser ablation resistance and mechanism of Si-Zr alloyed melt infiltrated C/C-SiC composite

Ablation resistance of C/C-SiC composite prepared via Si-Zr alloyed reactive melt infiltration was evaluated using a facile and economical laser ablation method. Linear ablation rates of the composite increased with an increase in laser power densities and decreased with extended ablation time. The C/C-SiC composite prepared via Si-Zr alloyed melt infiltration presented much better ablation resistance compared with the C/SiC composite prepared by polymer infiltration and pyrolysis process. The good ablation resistance of the composite was attributed to the melted ZrC layer formed at the ablation center region. Microstructure and phase composition of different ablated region were investigated by SEM and EDS, and a laser ablation model was finally proposed based on the testing results and microstructure characterization. Laser ablation of the composite experienced three distinct periods. At the very beginning, the laser ablation was dominated by the oxidation process. Then for the second period, the laser ablation was dominated by the evaporation, decomposition and sublimation process. With the further ablation of the composite, chemical stable ZrC was formed on the ablated surface and the laser ablation was synergistically controlled by the scouring away of ZrC melts and evaporation, decomposition and sublimation process.This work is supported by National Natural Science Foundation of China (51641502)

Key Technology of Real-Time Road Navigation Method Based on Intelligent Data Research

The effect of traffic flow prediction plays an important role in routing selection. Traditional traffic flow forecasting methods mainly include linear, nonlinear, neural network, and Time Series Analysis method. However, all of them have some shortcomings. This paper analyzes the existing algorithms on traffic flow prediction and characteristics of city traffic flow and proposes a road traffic flow prediction method based on transfer probability. This method first analyzes the transfer probability of upstream of the target road and then makes the prediction of the traffic flow at the next time by using the traffic flow equation. Newton Interior-Point Method is used to obtain the optimal value of parameters. Finally, it uses the proposed model to predict the traffic flow at the next time. By comparing the existing prediction methods, the proposed model has proven to have good performance. It can fast get the optimal value of parameters faster and has higher prediction accuracy, which can be used to make real-time traffic flow prediction

Management of acute appendicitis during the COVID-19 pandemic : a retrospective cohort study

Background: The Coronavirus Disease 2019 (COVID-19) pandemic profoundly impacted delivery of health care. South Western Sydney Local Health District (SWSLHD) experienced some of the highest cases, admissions and deaths during the Delta and Omicron waves in New South Wales. This study aims to determine the impact of the pandemic on emergency surgery services for adults presenting with acute appendicitis. Methods: A retrospective review of patient records was performed of adults presenting with acute appendicitis between 1st March 2021 and 31st March 2022, which was compared to a pre-COVID control period of the same dates in 2019–2020. Patients managed operatively or conservatively were included. Results: 1556 patients were included in the operative arm; 723 and 833 respectively in the study and control groups, which were comparable at baseline. 1.66% were COVID positive. During the pandemic, patients were significantly more likely to be investigated with computered tomography (CT) scan (p ≤ 0.001), present with complicated appendicitis (p = 0.03), and require caecectomy (p = 0.005). They had higher American Society of Anaesthesiology (ASA) scores (p = 0.001) and significantly lower negative appendectomy rates (p = 0.001). Fifty-two patients were included in the conservative arm; 29 and 23 respectively in the pandemic and control groups. Patients were comparable at baseline. There were two COVID positive patients. During the pandemic, there was a significant reduction in complications (p = 0.033), readmissions (0.044) and interval appendicectomy (p = 0.0044). Conclusion: We identified higher rates of complicated appendicitis, caecectomies and greater reliance on CT imaging preoperatively during the pandemic in SWSLHD

A Novel Latin Square Image Cipher

In this paper, we introduce a symmetric-key Latin square image cipher (LSIC) for grayscale and color images. Our contributions to the image encryption community include 1) we develop new Latin square image encryption primitives including Latin Square Whitening, Latin Square S-box and Latin Square P-box ; 2) we provide a new way of integrating probabilistic encryption in image encryption by embedding random noise in the least significant image bit-plane; and 3) we construct LSIC with these Latin square image encryption primitives all on one keyed Latin square in a new loom-like substitution-permutation network. Consequently, the proposed LSIC achieve many desired properties of a secure cipher including a large key space, high key sensitivities, uniformly distributed ciphertext, excellent confusion and diffusion properties, semantically secure, and robustness against channel noise. Theoretical analysis show that the LSIC has good resistance to many attack models including brute-force attacks, ciphertext-only attacks, known-plaintext attacks and chosen-plaintext attacks. Experimental analysis under extensive simulation results using the complete USC-SIPI Miscellaneous image dataset demonstrate that LSIC outperforms or reach state of the art suggested by many peer algorithms. All these analysis and results demonstrate that the LSIC is very suitable for digital image encryption. Finally, we open source the LSIC MATLAB code under webpage https://sites.google.com/site/tuftsyuewu/source-code.Comment: 26 pages, 17 figures, and 7 table

Establishing chromosomal design-build-test-learn through a synthetic chromosome and its combinatorial reconfiguration

Chromosome-level design-build-test-learn cycles (chrDBTLs) allow systematic combinatorial reconfiguration of chromosomes with ease. Here, we established chrDBTL with a redesigned synthetic Saccharomyces cerevisiae chromosome XV, synXV. We designed and built synXV to harbor strategically inserted features, modified elements, and synonymously recoded genes throughout the chromosome. Based on the recoded chromosome, we developed a method to enable chrDBTL: CRISPR-Cas9-mediated mitotic recombination with endoreduplication (CRIMiRE). CRIMiRE allowed the creation of customized wild-type/synthetic combinations, accelerating genotype-phenotype mapping and synthetic chromosome redesign. We also leveraged synXV as a "build-to-learn" model organism for translation studies by ribosome profiling. We conducted a locus-to-locus comparison of ribosome occupancy between synXV and the wild-type chromosome, providing insight into the effects of codon changes and redesigned features on translation dynamics in vivo. Overall, we established synXV as a versatile reconfigurable system that advances chrDBTL for understanding biological mechanisms and engineering strains. </p

Selection of Patients and Anesthetic Types for Endovascular Treatment in Acute Ischemic Stroke: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND:and Purpose Recent randomized controlled trials have demonstrated consistent effectiveness of endovascular treatment (EVT) for acute ischemic stroke, leading to update on stroke management guidelines. We conducted this meta-analysis to assess the efficacy and safety of EVT overall and in subgroups stratified by age, baseline stroke severity, brain imaging feature, and anesthetic type. METHODS:Published randomized controlled trials comparing EVT and standard medical care alone were evaluated. The measured outcomes were 90-day functional independence (modified Rankin Scale ≤2), all-cause mortality, and symptomatic intracranial hemorrhage. RESULTS:Nine trials enrolling 2476 patients were included (1338 EVT, 1138 standard medical care alone). For patients with large vessel occlusions confirmed by noninvasive vessel imaging, EVT yielded improved functional outcome (pooled odds ratio [OR], 2.02; 95% confidence interval [CI], 1.64-2.50), lower mortality (OR, 0.75; 95% CI, 0.58-0.97), and similar symptomatic intracranial hemorrhage rate (OR, 1.12; 95% CI, 0.72-1.76) compared with standard medical care. A higher proportion of functional independence was seen in patients with terminus intracranial artery occlusion (±M1) (OR, 3.16; 95% CI, 1.64-6.06), baseline Alberta Stroke Program Early CT score of 8-10 (OR, 2.11; 95% CI, 1.25-3.57) and age ≤70 years (OR, 3.01; 95% CI, 1.73-5.24). EVT performed under conscious sedation had better functional outcomes (OR, 2.08; 95% CI, 1.47-2.96) without increased risk of symptomatic intracranial hemorrhage or short-term mortality compared with general anesthesia. CONCLUSIONS:Vessel-imaging proven large vessel occlusion, a favorable scan, and younger age are useful predictors to identify anterior circulation stroke patients who may benefit from EVT. Conscious sedation is feasible and safe in EVT based on available data. However, firm conclusion on the choice of anesthetic types should be drawn from more appropriate randomized controlled trials

Recent Advances of Exciplex-Based White Organic Light-Emitting Diodes

Recently, exciplexes have been actively investigated in white organic light-emitting diodes (WOLEDs), since they can be effectively functioned as (i) fluorescent or thermally activated delayed fluorescent (TADF) emitters; (ii) the hosts of fluorescent, phosphorescent and TADF dopants. By virtue of the unique advantages of exciplexes, high-performance exciplex-based WOLEDs can be achieved. In this invited review, we have firstly described fundamental concepts of exciplexes and their use in organic light-emitting diodes (OLEDs). Then, we have concluded the primary strategies to develop exciplex-based WOLEDs. Specifically, we have emphasized the representative WOLEDs using exciplex emitters or hosts. In the end, we have given an outlook for the future development of exciplex-based WOLEDs