No abstract

No abstract

For the preparation of lightweight and high-performance electromagnetic interference shielding material, the poor dispersion of carbon nanotubes (CNTs) and weak interfacial strength degrade the mechanical properties of the polymer-based composite with extremely high filler contents. Herein cellulose nanofibers (CNFs) prepared by TEMPO-mediated oxidation exhibits a dispersive action for multiwalled carbon nanotube (MWCNTs) without chemical functionalization of the MWCNTs or the use of surfactant. Thus a robust and flexible CNF/MWCNT composite film can be fabricated by simple vacuum filtration and hot-pressing method. This composite film (thickness 0.15 mm) shows an electromagnetic interference shielding effectiveness (EMI SE) of 45.8 dB in the X-band. Thanks to the all-fiber structure and the association between CNFs and MWCNTs, it exhibits good flexibility and tensile strength up to 48 MPa, which is superior to other reported MWCNT-based films for electromagnetic shielding, giving it the potential to be used in flexible electronics and wearable devices.

No abstract

Background Adequate cytology is limited by insufficient cytologists in a large‐scale cervical cancer screening. We aimed to develop an artificial intelligence (AI)‐assisted cytology system in cervical cancer screening program. Methods We conducted a perspective cohort study within a population‐based cervical cancer screening program for 0.7 million women, using a validated AI‐assisted cytology system. For comparison, cytologists examined all slides classified by AI as abnormal and a randomly selected 10% of normal slides. Each woman with slides classified as abnormal by either AI‐assisted or manual reading was diagnosed by colposcopy and biopsy. The outcomes were histologically confirmed cervical intraepithelial neoplasia grade 2 or worse (CIN2+). Results Finally, we recruited 703 103 women, of whom 98 549 were independently screened by AI and manual reading. The overall agreement rate between AI and manual reading was 94.7% (95% confidential interval [CI], 94.5%‐94.8%), and kappa was 0.92 (0.91‐0.92). The detection rates of CIN2+ increased with the severity of cytology abnormality performed by both AI and manual reading (Ptrend < 0.001). General estimated equations showed that detection of CIN2+ among women with ASC‐H or HSIL by AI were significantly higher than corresponding groups classified by cytologists (for ASC‐H: odds ratio [OR] = 1.22, 95%CI 1.11‐1.34, P < .001; for HSIL: OR = 1.41, 1.28‐1.55, P < .001). AI‐assisted cytology was 5.8% (3.0%‐8.6%) more sensitive for detection of CIN2+ than manual reading with a slight reduction in specificity. Conclusions AI‐assisted cytology system could exclude most of normal cytology, and improve sensitivity with clinically equivalent specificity for detection of CIN2+ compared with manual cytology reading. Overall, the results support AI‐based cytology system for the primary cervical cancer screening in large‐scale population.

Clinical studies have demonstrated the predictive values of changes in electrocardiographic (ECG) parameters for the preexisting myocardial ischemic infarction. However, a simple and early predictor for the subsequent development of myocardial infarction during the ischemic phase is of significant value for the identification of ischemic patients at high risk. The present study was undertaken by using non-human primate model of myocardial ischemic infarction to fulfill this gap. Twenty male Rhesus monkeys at age of 2–3 years old were subjected to left anterior descending artery ligation. This ligation was performed at varying position along the artery so that it produced varying sizes of myocardial infarction at the late stage. The ECG recording was undertaken before the surgical procedure, at 2 h after the ligation, and 8 weeks after the surgery for each animal. The correlation of the changes in the ECG waves in the early or the late stage with the myocardial infarction size was analyzed. The R wave depression and the QT shortening in the early ischemic stage were found to have an inverse correlation with the myocardial infarction size. At the late stage, the R wave depression, the QT prolongation, the QRS score, and the ST segment elevation were all closely correlated with the developed infarction size. The poor R wave progression was identified at both the early ischemic and the late infarction stages. Therefore, the present study using non-human primate model of myocardial ischemic infarction identified the decreases in the R wave and the QT interval as early predictors of myocardial infarction. Validation of these parameters in clinical studies would greatly help identifying patients with myocardial ischemia at high risk for the subsequent development of myocardial infarction.

Multiwalled carbon nanotube (CNT) grafted poly­(l-lactide)-block-poly­(d-lactide) copolymer (CNT-L-D) was synthesized by ring opening polymerization of d-lactide on the end hydroxyls of poly­(l-lactide) (PLLA) prepolymers grafted on the surface of CNT. The stereocomplexation of solution cast and melt crystallized CNT-L-D, PLLA/CNT-L-D, and PDLA/CNT-L-D blends were investigated by differential scanning calorimetry, wide-angle X-ray diffraction, and optical microscopic observation. Solution cast and melt crystallized CNT-L-D copolymer form exclusive stereocomplex (sc) crystallites. The melting temperature, normalized crystallinity, and the fraction of sc crystallites for both solution cast and melt crystallized PDLA/CNT-L-D blends are higher than those of PLLA/CNT-L-D blends, indicating distinct stereocomplexation mechanisms in both blends. The heterogeneous nucleating effect of CNT makes the PLLA block grafted directly on CNT always participate in sc crystallite formation. So, for PDLA/CNT-L-D blends, the stereocomplexation mainly occurs between PLLA blocks and free PDLA molecules, and for PLLA/CNT-L-D blends, the stereocomplexation mainly occurs between PLLA blocks and PDLA blocks. The nucleating effect of CNT enhances the sc formation of free PDLA molecules during solution casting and melt crystallization by the introduction of CNT-L-D, and the sc crystallites can reform after complete melting. However, the dilution effect of free PLLA molecules to PDLA blocks lowered down the stereocomplex efficiency of PLLA/CNT-L-D blends compared with that of PDLA/CNT-L-D blends, especially during melt crystallization, and the morphology transition of sc crystallites occurs from original well-rounded Maltese-cross spherulites for PDLA/CNT-L-D blends to dendritic form in PLLA/CNT-L-D blends.

A facile and green route to fabricate sustainable and biodegradable tridimensional interconnected hierarchically meso- and macroporous polylactide (PLA) monoliths was developed. The tunable morphologies and controllable pore sizes of the monoliths based on the stereocomplex (sc) crystallization of poly­(l-lactide) (PLLA) and poly­(d-lactide) (PDLA) during the melt blending process were caused by the macro- and microphase separation between PLA and poly­(ethylene oxide) (PEO). The proposed approach can be easily scaled-up and is environmentally sustainable, and it involves neither any toxic chemical reagents nor templates. The hierarchical morphologies of the porous materials contain mesopores regulated by the sc crystallite network formed during melt processing and macropores induced by macrophase separation. The porous structure was influenced by PDLA contents seriously, and the construction of interconnected pores made up of sc crystallite tridimensional network appears at a low PEO content of 20 wt %. The porous polymer monolith featured very good hydrophobicity with a water contact angle over 135°, as well as the strong lipophilicity, endowing the materials with potential applications in selective oil–water separation. Moreover, the much higher thermal and chemical resistance of the porous PLA monoliths based on sc crystallite network allowed us to significantly broaden the applications of the adsorbent in some harsh conditions and catalytic systems compared to those based solely on PLLA.