Identifying critically ill patients at risk of death from coronavirus disease

BACKGROUND:A pandemic of coronavirus disease(COVID-19)has been declared by the World Health Organization(WHO)and caring for critically ill patients is expected to be at the core of battling this disease.However,little is known regarding an early detection of patients at high risk of fatality.METHODS:This retrospective cohort study recruited consecutive adult patients admitted between February 8 and February 29,2020,to the three intensive care units(ICUs)in a designated hospital for treating COVID-19 in Wuhan.The detailed clinical information and laboratory results for each patient were obtained.The primary outcome was in-hospital mortality.Potential predictors were analyzed for possible association with outcomes,and the predictive performance of indicators was assessed from the receiver operating characteristic(ROC)curve.RESULTS:A total of 121 critically ill patients were included in the study,and 28.9%(35/121)of them died in the hospital.The non-survivors were older and more likely to develop acute organ dysfunction,and had higher Sequential Organ Failure Assessment(SOFA)and quick SOFA(qSOFA)scores.Among the laboratory variables on admission,we identifi ed 12 useful biomarkers for the prediction of in-hospital mortality,as suggested by area under the curve(AUC)above 0.80.The AUCs for three markers neutrophilto-lymphocyte ratio(NLR),thyroid hormones free triiodothyronine(FT3),and ferritin were 0.857,0.863,and 0.827,respectively.The combination of two easily accessed variables NLR and ferritin had comparable AUC with SOFA score for the prediction of in-hospital mortality(0.901 vs.0.955,P=0.085).CONCLUSIONS:Acute organ dysfunction combined with older age is associated with fatal outcomes in COVID-19 patients.Circulating biomarkers could be used as powerful predictors for the in-hospital mortality.

Alpha-actinin expression at different differentiating time points from temporal lobe cerebral cortex neural stem cells to neuron-like cells using energy dispersive X-ray analysis

BACKGROUND： Alpha-actinin （ a -actinin） plays a key role in neuronal growth cone migration during directional differentiation from neural stem cells （NSCs） to neurons. OBJECTIVE： To detect in situ microdistribution and quantitative expression of a -actinin during directional differentiation of NSCs to neurons in the temporal lobe cerebral cortex of neonatal rats. DESIGN, TIME AND SETTING： Between January 2006 and December 2008, culture and directional differentiation of NSCs were performed at Department of Histology and Embryology, Preclinical Medical College, China Medical University. Immune electron microscopy was performed at Department of Histology and Embryology and Department of Electron Micrology, Preclinical Medical College, China Medical University. Spectrum analysis was performed at Laboratory of Electron Microscopy, Mental Research Institute, Chinese Academy of Sciences. MATERIALS： Basic fibroblast growth factor, epidermal growth factor, brain-derived nerve growth factor, type-1 insulin like growth factor, and a -actinin antibody were provided by Gibco BRL, USA; rabbit-anti-rat nestin monoclonal antibody, rabbit-anti-rat neuron specific enolase polyclonal antibody, and EDAX-9100 energy dispersive X-ray analysis were provided by PHILIPS Company, Netherlands. METHODS： NSCs, following primary and passage culture, were differentiated with serum culture medium （DMEM/F12 ＋ 10% fetal bovine serum ＋ 2 ng/mL brain-derived nerve growth factor ＋ 2 ng/mL type-1 insulin like growth factor）. MAIN OUTCOME MEASURES： Expression of a -actinin in neuron-like cells was quantitatively and qualitatively detected with immunocytochemistry using energy dispersive X-ray analysis. RESULTS： Immunocytochemistry, combined with electron microscopy, indicated that positive α -actinin expression was like a spheroid particle with high electron density. In addition, the expression was gradually concentrated from the nuclear edge to the cytoplasm and expanded into developing neurites, during differentiation of neural stem cells to neurons. Conversely, energy dispersive X-ray analysis indicated that the more mature the neural differentiation was, and the greater the expression of α -actinin. CONCLUSION： The gradual increase of α -actinin expression is related to growth, development, and maturity of differentiated neuron-like cells, in neonatal rat frontal lobe cortex, at different differentiating time points of NSCs to neurons.

Cooperative Multi-Agent Control for Autonomous Ship Towing Under Environmental Disturbances

Among the promising application of autonomous surface vessels(ASVs)is the utilization of multiple autonomous tugs for manipulating a floating object such as an oil platform,a broken ship,or a ship in port areas.Considering the real conditions and operations of maritime practice,this paper proposes a multi-agent control algorithm to manipulate a ship to a desired position with a desired heading and velocity under the environmental disturbances.The control architecture consists of a supervisory controller in the higher layer and tug controllers in the lower layer.The supervisory controller allocates the towing forces and angles between the tugs and the ship by minimizing the error in the position and velocity of the ship.The weight coefficients in the cost function are designed to be adaptive to guarantee that the towing system functions well under environmental disturbances,and to enhance the efficiency of the towing system.The tug controller provides the forces to tow the ship and tracks the reference trajectory that is computed online based on the towing angles calculated by the supervisory controller.Simulation results show that the proposed algorithm can make the two autonomous tugs cooperatively tow a ship to a desired position with a desired heading and velocity under the(even harsh)environmental disturbances.

Changes and significance of serum troponin in trauma patients: A retrospective study in a level I trauma center

BACKGROUND: Elevated troponin I(TnI) is common among trauma patients. TnI is an indicator of myocardial injury, but clinical diagnosis of blunt cardiac injury cannot be based solely on an increase in TnI. Therefore, this study aims to explore the changes and clinical significance of serum TnI in trauma patients. METHODS: The clinical data of consecutive trauma patients admitted to our trauma center between July 1, 2017 and July 31, 2020 were retrospectively analyzed. According to TnI levels within 24 hours of admission, patients were divided into the elevated and normal TnI groups. According to the TnI levels after 7 days of admission, a graph depicting a change in trend was drawn and then analyzed whether TnI was related to in-hospital mortality. RESULTS: A total of 166 patients(69 and 97 cases with elevated and normal TnI, respectively) were included in this study. The average hospital stay, intensive care time, mechanical ventilation time, and in-hospital mortality were higher in the elevated TnI group than in the normal TnI group(P<0.05). The TnI level of trauma patients gradually increased after admission and peaked at 48 hours(7.804±1.537 ng/mL). Subsequently, it decreased, and then recovered to normal within 7 days. However, 13 patients did not recover. Logistic regression analysis revealed that abnormal TnI at 7 days was independently related to in-hospital mortality. CONCLUSIONS: Trauma patients with elevated TnI levels may have a worse prognosis. Monitoring the changes in serum TnI is important, which can reflect the prognosis better than the TnI measured immediately after admission.

Implications of neuroimaging findings in addiction

Addiction is a chronic and often relapsing brain disorder characterized by drug abuse and withdrawal symptoms and compulsive drug seeking(Koob and Volkow,2010)when access to the drug is restricted.Addiction leads to structural and functional brain changes implicated in reward,memory,motivation,and control(Volkow et al.,2019;Lüscher et al.,2020).

Constitutive behavior and microstructural evolution in hot deformed 2297 Al-Li alloy

The microstructural evolution mechanism and constitutive behavior of 2297 Al-Li alloy were studied via thermal compression test with the constant strain rates of 0.001–1 s-1 and the deformation temperatures ranging from 623 to 773 K.To verify the predictable ability of diverse constitutive models under different stress states,the hot compression experiments with stress triaxiality varying from-0.33 to 0.46 were conducted.The microstructures of the deformed specimens under diverse deformation conditions are probed to reveal the mechanism of hot deformation behavior.The experimental results indicate that the work-hardening and dynamic softening are competitive during the hot compression process,and the dynamic softening is more obvious under low deformation temperature and high strain rate.The microstructural analysis manifests that the dynamic recovery gets predominant at high deformation temperature to produce fine grains.Meanwhile,the dynamic recrystallization becomes more dominant as the strain rate decreases,which is sensitive to the stress triaxiality.In addition,both the modified Johnson-Cook model and straincompensated Arrhenius-type function are suitable for describing the flow behavior of 2297 alloy,while the latter reveals a more accurate prediction.However,the predictability of the two kinds of models is worsened with the transformation of stress triaxiality,and the validity of the Arrhenius-type model is restricted by high stress triaxiality.

Detection and assessment of nitrogen effect on cold tolerance for tea by hyperspectral reflectance with PLSR, PCR, and LM models

Knowledge of nutrients effect on freezing tolerance is vital for protecting tea plants against cold injury(CI).Freezing injury treatments on tea leaves with different low temperature and nitrogen(N)concentration was evaluated by hyperspectral imaging based on the reflectance as potential analytical tool.Subsequently,quantitative evaluation of the CI was improved by comparing analyzed results using partial least squares regression(PLSR),principle component regression(PCR)and linear model(LM)models.Reflectance of the CI was obtained by hyperspectral imaging system in the band between 871 and 1766 nm.The results showed that average reflectance increases with the rise of N concentration.A substantial portion of the leaf from the plant with 100%N dosage had the darkest image and resulted in the highest reflectance because the N weakened the negative effect of freezing stress.Out of the five spectral domains tested,the best predictive accuracy for the CI of the tea leaf was achieved by PCR(R^(2)=0.9971,RMSE=0.0609)in 1410–1766 nm wavelength,followed by LM(R^(2)=0.9999,RMSE=0.0805)in 871–1000 nm.The whole interval had the worse prediction accuracy which could be caused by large variations in the data for a specific treatment and high absorption peak occurring around 1450 nm in the reflectance curve.The averages,R^(2) and RMSE for all the three statistical models showed that the worse prediction accuracy occurred in 1410–1766 nm,followed by the whole interval 871–1766 nm.The prediction accuracy was low which could be due to the strong water absorption peaks that appeared in both range of wavelengths.The models without absorption bands had improved correlation coefficient and reduced RMSE values between the measured and the predicted CI(R^(2)=0.9676;RMSE=0.3067)compared to the model developed with the reflectance values in the entire waveband(R^(2)=0.9504;RMSE=0.6629).The reflectance values where absorption bands occurred had detrimental effect on the model performance,which resulted in the lower correlation values and larger errors.This study has demonstrated that the wavelength at which absorption bands occur can influence model performance significantly which is a step towards real-time implementation of the technique.

Structural analysis on cutting notch of tea stalk by X-ray micro-computed tomography

Quantitative analysis on cutting notch of tea stalk is one method to better understand shear resistance and mechanical properties of the stalk,which could improve cutting performance and efficiency for tea harvesting.Optimal design of the cutter might be achieved through structural analysis of cutting notch by X-ray micro-computed tomography(micro-CT).The third inter-node of the stalks were sampled and scanned by micro-CT after they were cut at different cutting depths(0.7,1.5,2.3 mm)and cutting edge angles of cutter(30,35,40).The structural change of the cutting notch and cutting force was observed.Grey-scale histogram analysis and bimodal segmentation method were used to extract the information about cutting notch from 2D slice images.A 3D model of the stalk was established with reconstruction and volume rendering.Besides,maximum crosssectional area ratio of cutting notch(MCSARCN)and volume ratio of cutting notch(VRCN)were calculated.The results show that MCSARCN and VRCN had a closely relationship with the cutting force,cutting depth and cutting edge angle according to 3D tomographic images and 2D slice images.Both MCSARCN and VRCN increased with cutting depth,despite of cutting edge angle.For cutting edge angle of 30,35and 40at different cutting depths,MCSARCN increased from 4.89%to 9.47%,from 8.51%to 22.83%and from 4.30%to 16.87%,respectively.Meanwhile,VRCN increased from 1.59%to 2.13%,from 2.98%to 5.76%and from 3.04%to 5.01%,respectively.When cutting depth was 1.5 mm,cutting force increased but VRCN present a decreased trend with cutting edge angle.X-ray micro-CT could be used to analyze the structure on cutting notch of tea stalks which is helpful in optimizing the structural parameters of the cutter.