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Calcium carbonate is so hard to be further developed in polymer applications because it is difficult to combine with other materials. Starch-coated calcium carbonate was prepared by using starch as the main modifier and sodium stearate and sodium hexametaphosphate as the auxiliary modifiers. Optimal modification conditions were tested by single factor experiment and orthogonal experiment optimization. Manifestation was evaluated with the help of Fourier infrared spectrometer (FT-IR) and laser particle size analyzer and other test instruments. Results showed that a starch film was successfully coated on the surface of calcium carbonate, and the edges and corners of the modified coated calcium carbonate were passivated, and the particles were rounded. The active interface calcium carbonate has a broad application prospect in the field of degradable biomaterials.

Under the innovation system integrated with production, teaching and researching, the evolution mechanism of knowledge theme becomes central point in academic fields. However, previous researches mostly focused on analyzing the tendency of academic achievements, didn’t bring the potential interaction between the production and researching into consideration. In this paper we will use the co-integration analysis and Granger causality test methods, which are prevalent in economics research, to study the evolution of specific knowledge theme – “Cloud computing”. Our main purpose is to reveal the evolution mechanism as well as general principle of popularity of one theme.

Purpose: Strokes are challenging to diagnose in pediatric emergency departments (EDs) as level of suspicion is low and atypical presentations are common. We analyzed clinical features, epidemiology and factors of delayed identification in arterial ischemic strokes (AIS) and hemorrhagic strokes (HS). Methods: Single-centre retrospective cohort study of children aged between 29 days and 18 years old diagnosed with stroke between July 2016 to June 2021. Results: Among 36 children, 11 (30.5%) had AIS, 25 (69.4%) had HS. Median age for AIS was 9 years (interquartile range [IQR], 2 to 9) and HS 9 years (IQR, 1 to 11.5) (P=0.715). Focal neurological deficit was seen in 72.7% of AIS and 20% of HS (P=0.006). Only 18.2% of AIS and 52.0% of HS presented within 6 hours of symptoms. Median time from symptom onset to ED presentation was 24 hours (IQR, 12 to 28) for AIS and 7 hours (IQR, 1.8 to 48) for HS (P=0.595). Most (85.6%) arrived by own transport. Median time from presentation to neuroimaging was 7 hours (IQR, 0.9 to 7) for AIS and 4.8 (IQR, 1.3 to 16.8) hours for HS (P=0.376). Eleven patients, 9/25 (36.0%) HS and 2/11 (18.2%) AIS, did not have stroke as differential diagnosis at ED (P=0.714). Common initial diagnoses were viral illness or headaches. On univariate analysis, age <1 (odds ratio [OR], 17.5; 95% confidence interval [CI], 1.2 to 250.4; P=0.035) and absence of focal neurological deficit (OR, 13.091; 95% CI, 1.5 to 117.9; P=0.022) were significant factors for delayed identification. Conclusion: Index of suspicion for pediatric strokes among caregivers and clinicians should be increased. Public awareness campaigns are recommended.

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