Effect of oxygen-containing functional groups on the micromechanical behavior of biodegradable plastics and their formation of microplastics during aging.

Biodegradable plastics (BPs) are more prone to generate harmful microplastics (MPs) in a short time, which have always been ignored. Oxygenated functional group formation is considered to be a key indicator for assessing microplastic formation, while it is difficult to characterize at a very early stage. The micromechanical properties of the aging plastic during the formation of the MPs are highly influenced by the evolution of oxygen-containing functional groups, however, their relationship has rarely been revealed. Herein, we compared changes in the physicochemical properties of BPs and non-degradable plastic bags during aging in artificial seawater, soil, and air. The results showed that the oxidation of plastics in the air was the most significant, with the most prominent oxidation in BPs. The accumulation of carbonyl groups leads to a significant increase in the micromechanical properties and surface brittleness of the plastic, further exacerbating the formation of MPs. It was also verified by the FTIR, 2D-COS, AFM, and Raman spectroscopy analyses. Furthermore, the increased adhesion and roughness caused by oxygen-containing functional groups suggest that the environmental risks of BPs cannot be ignored. Our findings suggest that the testing of micromechanical properties can predicate the formation of the MPs at an early stage.

Variation of Young's modulus suggested the main active sites for four different aging plastics at an early age time.

Precisely determining which bonds are more sensitive when plastic aging occurs is critical to better understand the mechanisms of toxic release and microplastics formation. However, the relationship between chemical bonds with the active aging sites changes and the aging behavior of plastics at an early age is still unclear. Herein, the mechanical behavior of four polymers with different substituents was characterized by the high-resolution AFM. Young's modulus (YM) changes suggested that the cleavage of C-Cl bonds in PVC, C-H bonds in PE and PP, and C-F bonds in PTFE are the main active aging sites for plastic aging. The aging degree of the plastics followed the order of PVC > PP > PE > PTFE. Two aging periods exhibited different YM change behavior, the free radical and cross-linking resulted in a minor increase in YM during the initiation period. Numerous free radicals formed and cross-linking reaction happened, causing a significant increase in YM during the propagation period. Raman spectroscopy verified the formation of microplastics. This research develops promising strategies to quantitatively evaluate the aging degrees using AFM and establish the relationship between chemical bonds and mechanical behavior, which would provide new method to predict plastic pollution in actual environments.

Structured-Light 3D Imaging Based on Vector Iterative Fourier Transform Algorithm.

Quasi-continuous-phase metasurfaces overcome the side effects imposed by high-order diffraction on imaging and can impart optical parameters such as amplitude, phase, polarization, and frequency to incident light at sub-wavelength scales with high efficiency. Structured-light three-dimensional (3D) imaging is a hot topic in the field of 3D imaging because of its advantages of low computation cost, high imaging accuracy, fast imaging speed, and cost-effectiveness. Structured-light 3D imaging requires uniform diffractive optical elements (DOEs), which could be realized by quasi-continuous-phase metasurfaces. In this paper, we design a quasi-continuous-phase metasurface beam splitter through a vector iterative Fourier transform algorithm and utilize this device to realize structured-light 3D imaging of a target object with subsequent target reconstruction. A structured-light 3D imaging system is then experimentally implemented by combining the fabricated quasi-continuous-phase metasurface illuminated by the vertical-cavity surface-emitting laser and a binocular recognition system, which eventually provides a new technological path for the 3D imaging field.

Curcumin may reverse 5-fluorouracil resistance on colonic cancer cells by regulating TET1-NKD-Wnt signal pathway to inhibit the EMT progress.

BACKGROUND AND PURPOSE: Colorectal cancer is a kind of gastrointestinal tumor with rising morbidity and mortality. 5-fluorouracil is one of the most effective chemotherapy drugs for the treatment of CRC. However, clinical data reported dramatic resistance on the treatment for CRC with 5-fluorouracil. Present study aims to explore the anti-resistant effect of curcumin and its mechanism. METHODS: MTT assay was used to evaluate the proliferation of rHCT-116 cells. Flow cytometry was used to determine the apoptosis and cell cycle of rHCT-116 cells. Western Blot was performed to detect the expression level of TET1, NKD2, E-cadherin, Vimentin, ß-catenin, TCF4 and Axin in transfected rHCT-116 cells. RESULTS: 5-fluorouracil resistant HCT-116 cells were successfully established. Curcumin was found to be effective in the inhibition of proliferation, inducement of apoptosis and block of G0/G1 phase on 5-fluorouracil treated HCT-116 cells. The expression of TET1 and NKD2 was greatly inhibited by high dosage of curcumin. The WNT signal pathway and EMT progress were suppressed in rHCT-116 cells by high dosage of curcumin. The inhibitory effects of curcumin on WNT signal pathway and EMT progress were verified to be consistent with Pax-6, TET1 and NKD2. CONCLUSION: Curcumin might exert anti-resistant effect of 5-FU on HCT-116 cells by regulating the TET1-NKD2-WNT signal pathway to inhibit the EMT progress.

Prevention of oxaliplatin-related neurotoxicity by ω-3 PUFAs: A double-blind randomized study of patients receiving oxaliplatin combined with capecitabine for colon cancer.

BACKGROUND: Peripheral neurotoxicity (PN) is a frequent side effect of oxaliplatin treatment, and also is its dose-limiting toxicity. Studies have confirmed that ω-3 polyunsaturated fatty acids (ω-3 PUFAs) had a neuroprotective effect. However, the efficacy of ω-3 PUFAs on the prevention of oxaliplatin-related neurotoxicity remains unclear. We assessed the effect of ω-3 PUFAs on the neurotoxicity in colon cancer patients treated by oxaliplatin combined with capecitabine. METHODS: In a randomized, double-blind, placebo-controlled study, 179 patients with colon cancer receiving oxaliplatin combined with capecitabine were recruited, and randomly assigned to take ω-3 PUFAs, 640 mg t.i.d during chemotherapy and 1 month after the end of the treatment or placebo. All patients were treated with chemotherapy for 6 treatment cycles. The incidence and severity of PN were evaluated, and the nerve conduction was measured before the onset of chemotherapy and 1 month after treatment. In addition, the quality of life was also accessed using Chinese version of European organization for research and treatment of cancer quality of life questionnaire. RESULTS: The incidence of PN in the ω-3 PUFAs group and placebo group was 52.22% and 69.66%, respectively (P = .017). In addition, there was a significant difference in the severity of PN between the 2 groups (P = .017). In terms of motor and sensory nerve conduction, the sensory action potentials amplitude of sural nerve in the ω-3 PUFAs group and placebo group after chemotherapy treatment were (15.01 ±â€Š3.14) and (13.00 ±â€Š3.63) µ V respectively, suggesting there was a significant difference in the 2 groups (P = .000). In addition, the mean score of the global health-status/quality of life was obviously higher in the ω-3 PUFAs group than that in the placebo group. CONCLUSION: ω-3 PUFAs seem to reduce the incidence and severity of oxaliplatin-related neurotoxicity, and improve the quality of patients' life, indicating it is expected to be a potential drug for the treatment of oxaliplatin-related neurotoxicity.