Laser Direct Writing of Flexible Sensor Arrays Based on Carbonized Carboxymethylcellulose and Its Composites for Simultaneous Mechanical and Thermal Stimuli Detection.

Multifunctional sensing devices with high flexibility, high sensitivity, and scalable fabrication are inevitable components of Internet of Things (IoT) for human-machine interfaces, structural health monitoring, and soft robots. Herein, high-performance flexible sensor arrays using carboxymethylcellulose (CMC) and its composite were developed for mechanical and thermal stimuli detection by laser direct writing. CMC contains abundant carbon precursors for strain-sensitive laser-carbonized CMC (LC-CMC), while the incorporation of graphene oxide (GO) into CMC leads to the formation of thermal-sensitive laser-carbonized GO/CMC (LC-GO/CMC). The LC-CMC-based strain sensor delivers gauge factors of 487.7 (strain < 8.5%) and 8557 (8.5% < strain < 14%), with long-term stability over 10 000 cycles. With 0.2 wt % GO, the LC-GO/CMC-based device provides a temperature coefficient of resistance of -0.289% °C -1, higher than the Cr-based commercial sensor. The potential application of the devices in IoT is proved by combining the near-field communication technology with the LC-CMC-based device to monitor the strain suffered by 316L stainless steel during the fatigue test. Moreover, an integrated device based on the strain and temperature sensing arrays accomplishes the simultaneous measurement of temperature and mechanical deformation in real time.

An optofluidic conveyor for particle transportation based on a fiber array and photothermal convection.

In this paper, a thermal convection-based optofluidic conveyor has been introduced, which can flexibly capture and manipulate multiple 20-120 µm silica particles with utmost accuracy. Near the end face, a fiber-based light source can confine 100 µm silica particles within 100 microns. By switching the light source of the fiber array, centimeter-range transportation of 100 µm SiO2 particles has been successfully achieved, which was not possible in optical trapping devices as we know. Through the comparative experiment with silica, polystyrene, and zirconium dioxide particles, the presented conveyor system is proved to be independent of the particles' dielectric properties. Moreover, sorting of silica and polystyrene particles based on the difference of mass densities has also been achieved. Additionally, the components of this conveyor (fiber array) and chip parts (microfluidic chamber) are freely detachable. Here, instead of expensive laser systems, a non-coherent light source has been utilized, which eventually eliminates the use of optical lens assemblies. All these features lead to making the equipment extremely simple in structure and low in cost. Besides, this optofluidic conveyor can be applied to transmit and sort various objects such as blood/cancer cells and microorganisms.

Acid-Interface Engineering of Carbon Nanotube/Elastomers with Enhanced Sensitivity for Stretchable Strain Sensors.

Stretchable strain sensors with high sensitivity or gauge factor (GF), large stretchability, and long-term durability are highly demanded in human motion detection, artificial intelligence, and electronic skins. Nevertheless, to develop high-sensitive sensors without sacrificing the stretchability cannot be realized using simple device configurations. In this work, an acid-interface engineering (AIE) method was proposed to develop a stretchable strain sensor with high GF and large stretchability. The AIE generates a layer of SiO x at the interface between the carbon nanotube (CNT) film and Ecoflex, playing a key role in enhancing the sensor's GF. Compared to devices without AIE (GF = 2.4), the ones with AIE are significantly improved. At an AIE time of 10 min, the GF up to 1665.9 is achieved without sacrificing the stretchability (>100%). The AIE-generated cracks are found to modulate the electrical behaviors and enhance the GFs of sensors with AIE through the crack-induced rapid reduction in the electrical conduction pathway, which is manipulated by the CNTs bridging over the cracks. The device with AIE proves its high mechanical durability through a cycling test (>10 000 cycles) at a high strain up to ∼80%, further paving its practical applications in various human motion detections.

Early lactate clearance as a reliable predictor of initial poor graft function after orthotopic liver transplantation.

BACKGROUND: Initial poor graft function (IPGF) following orthotopic liver transplantation is a major determinant of postoperative survival and morbidity. Lactate clearance is a good marker of liver function. In this study, we investigated the clinical utility of early lactate clearance as an early and accurate predictor for IPGF following liver transplantation. METHODS: This was a prospective observational study of 222 patients referred to the surgical intensive care unit (SICU) after orthotopic liver transplantation. The IPGF group consisted of patients with alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) >1500 IU/L within 72 hours after orthotopic liver transplantation. Early lactate clearance was defined as lactate at SICU presentation (hour 0) minus lactate at hour 6, divided by lactate at SICU presentation. The model for end-stage liver disease (MELD) score, Child-Pugh score and laboratory data including AST, ALT, total bilirubin (TB) and prothrombin time (PT) were recorded at SICU presentation and compared between the non-IPGF and IPGF groups. Receiver operating characteristic (ROC) curves were plotted to measure the performance of early lactate clearance, MELD score, Child-Pugh score, TB and PT. RESULTS: IPGF occurred in 45 of the 222 patients (20.3%). The early lactate clearance in the non-IPGF group was markedly higher than that in the IPGF group (43.2+/-13.8% vs 13.4+/-13.7% P<0.001). The optimum cut-off value for early lactate clearance predicting IPGF was 24.8% (sensitivity 95.5%, specificity 88.9%). The area under the curve of the ROC was 0.961, which was significantly superior to MELD score, Child-Pugh score, TB and PT. Patients with early lactate clearance ≤24.8% had a higher IPGF rate (OR=169) and a higher risk of in-hospital mortality (OR=3.625). CONCLUSIONS: Early lactate clearance can serve as a prompt and accurate bedside predictor of IPGF. Patients with early lactate clearance less than 24.8% are associated with a higher incidence of IPGF.

[Experimental study of human colon cell line Lovo transfected with soluble vascular endothelial growth factor receptor 1 gene].

OBJECTIVE: To investigate the effect of transfection with human soluble vascular endothelial growth factor receptor-1(sFlt-1) gene on cell growth and vascular endothelial growth factor (VEGF) concentration of the culture supernatant in human colon cancer cell line Lovo. METHODS: The recombinant plasmid pcDNA3-sFlt-1 containing sFlt-1 gene was transfected into Lovo cells by Lipofectamine 2000, which was identified by RT-PCR and ELISA. The effect of sFlt-1 protein on cell growth and VEGF expression in Lovo cells were investigated by MTT and ELISA. RESULTS: The recombinant plasmid pcDNA3-sFlt-1 was successfully transfected into Lovo cells. The sFlt-1 expression was identified by RT-PCR and ELISA, which inhibited the growth of Lovo cells and reduced the VEGF concentration in the culture supernatant compared with control. The inhibitory rates of proliferation of Lovo cells via MTT assay after 2,14,21 and 28 days were(23.92+/-9.16)%, (13.98+/-10.21)%,(22.54+/-11.92)% and (33.43+/-9.34)% respectively. Compared with the control groups, the differences were significant (P<0.05, P<0.01). CONCLUSION: Transfection with sFlt-1 gene into Lovo cells results in the expression of sFlt-1 protein, which possesses high biological activity and inhibits the growth of cancer cells.