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PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0256194
Author(s):  
Shengkun Peng ◽  
Lingai Pan ◽  
Yang Guo ◽  
Bo Gong ◽  
Xiaobo Huang ◽  
...  

Objectives COVID-19 and Non-Covid-19 (NC) Pneumonia encountered high CT imaging overlaps during pandemic. The study aims to evaluate the effectiveness of image-based quantitative CT features in discriminating COVID-19 from NC Pneumonia. Materials and methods 145 patients with highly suspected COVID-19 were retrospectively enrolled from four centers in Sichuan Province during January 23 to March 23, 2020. 88 cases were confirmed as COVID-19, and 57 patients were NC. The dataset was randomly divided by 3:2 into training and testing sets. The quantitative CT radiomics features were extracted and screened sequentially by correlation analysis, Mann-Whitney U test, the least absolute shrinkage and selection operator (LASSO) logistic regression (LR) and backward stepwise LR with minimum AIC methods. The selected features were used to construct the LR model for differentiating COVID-19 from NC. Meanwhile, the differentiation performance of traditional quantitative CT features such as lesion volume ratio, ground glass opacity (GGO) or consolidation volume ratio were also considered and compared with Radiomics-based method. The receiver operating characteristic curve (ROC) analysis were conducted to evaluate the predicting performance. Results Compared with traditional CT quantitative features, radiomics features performed best with the highest Area Under Curve (AUC), sensitivity, specificity and accuracy in the training (0.994, 0.942, 1.0 and 0.965) and testing sets (0.977, 0.944, 0.870, 0.915) (Delong test, P < 0.001). Among CT volume-ratio based models using lesion or GGO component ratio, the model combining CT lesion score and component ratio performed better than others, with the AUC, sensitivity, specificity and accuracy of 0.84, 0.692, 0.853, 0.756 in the training set and 0.779, 0.667, 0.826, 0.729 in the testing set. The significant difference of the most selected wavelet transformed radiomics features between COVID-19 and NC might well reflect the CT signs. Conclusions The differentiation between COVID-19 and NC could be well improved by using radiomics features, compared with traditional CT quantitative values.


Author(s):  
R. N. Mamleev

Inhibitor-protected cephalosporins are an important tool against hospital infections caused by extended spectrum β-lactamase producers. At the same time, the relative deficiency of the basic antibiotic in combination with the β-lactamase inhibitor sulbactam (1: 1) may be associated with the risk of therapeutic failure.Objective. To compare therapeutic effect of various regimens for prescribing inhibitor-protected cephalosporins in children with severe bacterial infection.Children characteristics and research methods. The authors compared clinical efficacy of cefotaxime / sulbactam, cefoperazone / sulbactam, cefepime / sulbactam at maximum doses and main component-fortified-cefepime / sulbactam. The study included 92 patients aged from 2 months to 12 years with appendicular peritonitis, acute purulent osteomyelitis, complicated hospital infections of the lower respiratory tract, exacerbation of chronic purulent otitis media and chronic urinary tract infections. It was found that inhibitor-protected cephalosporins with a 1: 1 ratio of components more often necessitated a change in therapy. The use of drugs initially containing a basic antibiotic in a high dose (component ratio 2:1) or additionally fortified with a basic antibiotic demonstrated a higher therapeutic efficacy.


2021 ◽  
Vol 5 (10) ◽  
pp. 257
Author(s):  
Charini P. Maladeniya ◽  
Rhett C. Smith

Terpenoids are potentially sustainable replacements for petrochemical olefins. Sulfur is a waste product produced in large quantities from fossil fuel refining. Several composites with attractive properties have recently been made from terpenoids and sulfur. This report details the extent to which the ratio of sulfur to terpenoid and the terpenoid olefin content influences the thermal and mechanical properties of such terpenoid-sulfur composites. The terpenoids selected were diunsaturated geraniol and triunsaturated farnesol that, upon their inverse vulcanization with elemental sulfur, yield composites GerSx and FarSx, respectively (x = wt % sulfur). The wt % sulfur in the monomer feed was varied from 30–95 for this study, providing twelve materials. Mechanical analysis of these materials was undertaken by compressive and tensile strength techniques. Differential scanning calorimetric analysis revealed both polymeric and orthorhombic sulfur present in the materials with glass transition temperatures (Tg) of −37 °C to −13 °C and melt temperatures (Tm) of 119 to 104 °C. The crystallinity of composites decreases as the weight fraction of sulfur decreases and composites having the highest olefin content exhibit no detectable crystalline microstructures. The compressive strength of the materials showed increasing strength for higher olefin-content materials for both GerSx (with compressive strength of up to 32 MPa) and FarSx (with compressive strength of up to 43 MPa). The improved strength with increasing olefin content levels off at around 80–85% of terpenoid, after which point both tensile and compressive strength diminish.


2021 ◽  
Vol 3 ◽  
Author(s):  
Seiji Matsumura ◽  
Ken Watanabe ◽  
Naoki Saijo ◽  
Yuuki Ooishi ◽  
Toshitaka Kimura ◽  
...  

Elite athletes achieve superior performance under high pressure in competitive situations. Although it is known that such situations affect the precompetitive activity of their autonomic nervous system (ANS), the relationship between precompetitive ANS activity and performance remains controversial. Especially in extreme sports, it has been shown that cardiac sympathetic tone occurs in athletes before competition attempts. However, the relationship between precompetitive sympathetic tone and performance is unclear. To investigate this relationship in extreme sports, we organized a freestyle snowboard jumping competition and examined competitors' physiological states and performance during this event. The electrocardiograms (ECGs) of 20 elite snowboarders were measured 10 min before each jump in different competitive situations: practice, qualifying, and final sessions. The mean heart rate (HR), the low-frequency to high-frequency component ratio (LF/HF ratio), the logarithm of the HF (lnHF) component of the frequency-domain of the heart rate variability (HRV), the ratio of the standard deviation of all R–R intervals to the root mean square of successive differences of R–R intervals (SDNN/rMSSD ratio), and the rMSSD of the time-domain of the HRV were calculated from the ECG data. The results showed a significant increase in the mean HR as well as significant decreases in the lnHF component and rMSSD of the HRV as the sessions progressed. Interestingly, the mean HR, LF/HF ratio and SDNN/rMSSD ratio of the HRV showed significant positive correlations with competitive scores, and the lnHF component and rMSSD of the HRV showed significant negative correlations with the scores. Our results indicate that precompetitive ANS activity becomes predominantly sympathetic in elite extreme athletes, such as freestyle snowboarders, when the competition intensifies, and that this sympathetic predominance is positively related to competitive performance.


Author(s):  
Nguyen Thuy Chinh ◽  
Vu Quoc Manh ◽  
Thai Hoang ◽  
Kavitha Ramadass ◽  
C.I. Sathish ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4345
Author(s):  
Jae-Hoon Jeong ◽  
Kiwon Park

Topics concerning autonomous navigation, especially those related to positioning systems, have recently attracted increased research attention. The commonly available global positioning system (GPS) is unable to determine the positions of vehicles in GPS-shaded regions. To address this concern, this paper presents a fuzzy-logic system capable of determining the position of a moving robot in a GPS-shaded indoor environment by analyzing the chromaticity and frequency-component ratio of LED lights installed under the ceiling. The proposed system’s performance was analyzed by performing a MATLAB simulation of an indoor environment with obstacles. During the simulation, the mobile robot utilized a fuzzy autonomous navigation system with behavioral rules to approach targets successfully in a variety of indoor environments without colliding with obstacles. The robot utilized the x and y coordinates of the fuzzy positioning system. The results obtained in this study confirm the suitability of the proposed method for use in applications involving autonomous navigation of vehicles in areas with poor GPS-signal reception, such as in tunnels.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1623
Author(s):  
Anton A. Babaev ◽  
Anastasiia V. Sokolova ◽  
Sergei A. Cherevkov ◽  
Kevin Berwick ◽  
Alexander V. Baranov ◽  
...  

PL intensity quenching and the PL lifetime reduction of fluorophores located close to graphene derivatives are generally explained by charge and energy transfer processes. Analyzing the PL from PbS QDs in rGO/QD systems, we observed a substantial reduction in average PL lifetimes with an increase in rGO content that cannot be interpreted solely by these two processes. To explain the PL lifetime dependence on the rGO/QD component ratio, we propose a model based on the Auger recombination of excitations involving excess holes left in the QDs after the charge transfer process. To validate the model, we conducted additional experiments involving the external engineering of free charge carriers, which confirmed the role of excess holes as the main QD PL quenching source. A mathematical simulation of the model demonstrated that the energy transfer between neighboring QDs must also be considered to explain the experimental data carefully. Together, Auger recombination and energy transfer simulation offers us an excellent fit for the average PL lifetime dependence on the component ratio of the rGO/QD system.


2021 ◽  
Vol 7 (6) ◽  
Author(s):  
U. Abdaliev

The article experimentally investigated that using a carboxylic acid (acetic acid), non-free radicals of saturated hydrocarbons (gasoline, kerosene, white alcohol, benzene, toluene, acids, etc.) are split and form free radicals, after which a chemical reaction occurs in as a result of which new connections are formed. A stable milk-emulsion composite fuel was obtained by the nephelometric method, with the following component ratio: 5:0.2:4.8 (50% gasoline, 2% glacial acetic acid, 48% ordinary water). After obtaining a stable milk-emulsion composite fuel, combustion was carried out and the process of stable combustion was determined. The pressure of the composite fuel in the container is increased to 3 kg/cm2 to obtain an aerosol at the nozzle outlet. The aerosol ignites inside the nichrome coil, the heating temperature is about 500 °C. To maintain the process of stable combustion of the composite fuel, the spiral is connected to a 20-volt voltage source.


2021 ◽  
Author(s):  
Shuyi Chu ◽  
Qian Qu ◽  
Keke Pan ◽  
Yunjie Xu ◽  
Jibo Xiao

Abstract A new Fe-C porous filter material was prepared with dredged sediment of river as raw material. The orthogonal test L9(34) and component ratio experiment of raw material were conducted to investigate the optimum technological condition. Further, the filter obtained was characterized by Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), energy dispersive X-ray spectroscope (EDS), and X-ray diffraction (XRD). Results showed that the optimal technological condition was sludge: straw: starch: iron powder: foam: iron powder 74.5∶10∶7.5∶3∶5, preheating temperature 280 ℃, preheating 15 min, sintering temperature 1080 ℃, and sintering 11 min. The BET surface area of the filter was 3.32 m2 g− 1, and average pore size was 10.05 nm. Phase composition mainly included SiO2, Fe3O4, Fe2O3 and muscovite (KAl2(Si3Al)O10(OH)2). Average effluent concentrations of total phosphorus (TP), total organic carbon (TOC), and total nitrogen (TN) of the biofilter system filled with the filter obtained were decreased to 0.08, 3.43, and 3.76 mg L− 1, separately, at hydraulic retention time 4 h. Thus, the filter prepared with dredged sediment of rive as raw material is an alternative material for polluted river water purification.


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