Improved piezoelectricity of porous cellulose material via flexible polarization-initiate bridge for self-powered sensor.

Self-powered piezoelectric sensors based on cellulose nanocrystal (CNC) porous materials are light-weight and portable, whereas using unmodified CNCs can hardly obtain enough piezoelectric properties without external strong polarization due to its irreversible deformation caused by low toughness. Here, we bonded rod-like CNCs with a soft polymer, poly ethylene glycol (PEG), and hypothesized that PEG could toughen the material and its dielectric signal could induce the CNC polarization. We further adsorbed graphene (GR) as surface electrodes to prepare a CNC-PEG-GR piezoelectric porous material with density of 0.096 g·cm-3. The voltage output reached maximum when the frequency matched the dielectric relaxation frequency of PEG. We also increased the length-diameter ratio of porous material pores from 1.1 to 3.3 by adjusting its freeze-drying process, and the voltage output could reach to 0.7 V at a moderate ratio. They could be conveniently integrated into portable self-powered sensors applied to the intelligent wearable electronic devices.

Growth inhibition and apoptosis-inducing effect on human cancer cells by RCE-4, a spirostanol saponin derivative from natural medicines.

Reineckia carnea has been used to treat several diseases in folk remedies. RCE-4 has been isolated from several plants of the family Liliaceae, but its biological activity has not yet been reported. In the present study, we found that RCE-4 exhibited potent cytotoxicity to the tested human cancer cell lines, and the CaSki cell line was the most sensitive with an IC50 of 3.37 µM. Thus, we presented the apoptosis-inducing effect of RCE-4 on CaSki cervical cancer cells and investigated the relevant mechanisms. Based on observations using transmission electron microscopy, RCE-4-treated cells manifested nuclear shrinkage, condensation and fragmentation. Annexin V/PI dual staining flow cytometry assay further confirmed that RCE-4 caused a dose-dependent early apoptotic effect. Prior to these events, RCE-4 triggered a rapid decrease of the mitochondrial membrane potential and caused the release of cytochrome c from the mitochondria into the cytoplasm. RCE-4 increased the expression of Bax and decreased the expression of Bcl-2, thus augmenting the Bax/Bcl-2 ratio. These findings suggest that RCE-4 induces mitochondrial-mediated apoptosis in CaSki cells and has the potential to be developed as an anticancer agent.

Toxicity and influences of the alkaloids from Cynanchum komarovii AL. Iljinski (Asclepiadaceae) on growth and cuticle components of Spodoptera litura Fabricius (Noctuidae) larvae.

The acute lethal toxicity of the extracted and purified gross alkaloids from Cynanchum komarovii has been demonstrated on the insect pest, Spodoptera litura. The toxic regression equation of the gross alkaloids for S. litura larvae was Y = -2.69701 + 0.78711X and the LC(50) value 2669.88 mg L(-1). The growth disruptions of S. litura caused by the alkaloids from C. komarovii were also evaluated. The rates of growth inhibition, malformation, developmental duration (from third instar to pupation), pupation and emergence inhibition of S. litura caused by the gross alkaloids at dose rates between 50 and 800 mg L(-1) were 30.13-91.71%, 0.00-20.00%, 12-72 h, 16.66-36.66% and 16.66-50.00%, respectively. The alkaloids caused the modification of the cuticular components of S. litura. The relative contents of cuticular lipids, proteins and chitins showed a 3.02-17.11% rise before exposure, followed by 2.29-12.96% and 0.75-4.13% declines 72 h after treatment with gross alkaloids with concentrations between 50 and 800 mg L(-1). Initial studies on the insecticidal properties of C. komarovii gross alkaloids indicate these to be very potent insect growth inhibitors.