A High-Performance N2-Selective MXene Membrane with Double Selectivity Mechanism for N2/CH4 Separation.

Membrane-based separation process for unconventional natural gas purification (mainly N2/CH4 separation) has attracted more attention due to its considerable economic benefits. However, the majority of separation membranes at this stage, particularly N2-selective membranes, achieve the desired separation target by mainly relying on the diffusivity-selectivity mechanism. To overcome the limitation of a single mechanism, 2D lamellar MXene membranes with a double selectivity mechanism are prepared to enhance N2 permeance and N2/CH4 selectivity via introducing unsaturated metal sites into MXene, which can form specific interactions with N2 molecules and enhance N2 permeation. The resulting membranes exhibit an inspiring N2/CH4 separation performance with an N2 permeance of 344 GPU and N2/CH4 selectivity of 13.76. The collaboration of the double selectivity mechanism provides a new idea for the development of a novel N2-selective membrane for N2 removal and CH4 purification, which further broadens the application prospects of membrane separation technology in the field of unconventional natural gas purification.

Carbon nanomaterials treated by combination of oxidation and flash for highly efficient solar water evaporation.

The high-efficiency solar evaporation is a potential technique to desalinate hypersaline wastewater and seawater to alleviate the global fresh water shortage. Photo-thermal agent and solar evaporator with low-cost raw materials, high photo-thermal conversion efficiency and simple-fast preparation methods is crucial to realize the industrial application of solar evaporation. Herein, carbon nanomaterial with higher light absorption and photo-thermal conversion efficiency than that of carbon black was obtained by combination treatment of carbon black with oxidation and flash illumination. In order to characterize the evaporation performance of the devices, a floating evaporator was fabricated with the carbon nanomaterial on the top of polyethylene foam wrapped with non-woven fabrics. The evaporation rate and photo-thermal conversion efficiency of evaporators were affected significantly by environmental temperature and humidity. At the environmental temperature of 19.5 °C, the evaporator fabricated with the combined treated carbon nanomaterial as photo-thermal agents presents a stable evaporation rate at 1.27 kg m-2 h-1 and solar evaporation efficiency at 78.7% under 1 kW m-2 simulated sun illumination, which are higher than those of evaporator with carbon black (1.13 kg m-2 h-1 and 68.1%). The distilled water obtained from the solar evaporator met the standards of drinkable water. Overall, the experimental result demonstrates a great promise application of treated carbon nanomaterial as a photo-thermal agent in the field of seawater desalination and solar-energy collector.

[Application of standardized uptake value for FDG PET-CT in predicting radiation pneumonitis].

OBJECTIVE: To investigate the correlation of radiation pneumonitis (RP) with standardized uptake value (SUV) for fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET-CT) in lung cancer patients treated with radiation therapy. METHODS: Fourty patients with unresectable non-small cell lung cancer (NSCLC) received FDG PET-CT before and after radiotherapy. The average SUV of the lung tissue irradiated with a dose of < or = 5 Gy, 5.1 approximately 15 Gy, 15.1 approximately 35 Gy, 35.1 approximately 60 Gy, >60 Gy were measured. The correlation between SUV and RP was analyzed by comparing the SUV in the patients with RP and without. The SUV ratio of the irradiated lung tissue to that of the non-irradiated lung tissue (L/B) was also calculated. RESULTS: Of the 40 patients, 8 developed RP, including 6 cases of grade 2 and 2 cases of grade 3. The SUV of irradiated lung tissues with a dose of 35.1 approximately 60 Gy was significantly correlated with RP. When SUV > or =1, the RP incidence rate was 41.7% versus 20.0% in the whole group, with a statistically significant difference. (chi2 = 3.96, P < 0.05). The sensitivity and specificity of SUV in predicting RP was 62.5% and 78.1%, respectively. When the value of L/B > or = 2.5, the RP incidence rate was 40.7% in this group versus 20.0% in the whole group, with a statistical significance (chi(2) = 4.92, P < 0.05). If taking L/B > or = 2.5 as a threshold value, the sensitivity and specificity in predicting RP was 72.7% and 90.9%, respectively. No statistically significant difference was found in predicting radiation pneumonitis between SUV > or =1 and L/B > or = 2.5 (chi2 = 0.002, P > 0.05). CONCLUSION: The standardized uptake value (SUV) and the SUV ratio of the irradiated lung tissue to that of the non-irradiated lung tissue (L/B) for FDG PET-CT are positively correlated with radiation pneumonitis, and clinicians may use it to predict the occurrence of radiation pneumonitis.

[Diffraction enhanced imaging of condylar cartilage of osteoarthritic rats].

OBJECTIVE: To observe the images of early lesions of condylar cartilage of osteoarthritic rats in synchrotron radiation diffraction enhanced imaging (DEI). METHODS: The animal model of temporomandibular joint osteoarthrosis was established in rat following the method of partial resection of the joint disc. The changes of osteoarthritic condylar cartilage in different pathological stages were observed by DEI and compared with those in situ histopathological sections. RESULTS: With DEI, straight and orbicular lines were detected in condylar cartilage 45 to 60 days after discs resection. The lines were confirmed by histopathology to be collagen degradation and tiny fissure formation inside the cartilage. CONCLUSIONS: DEI is capable of imaging the early stages of pathological changes of excised condylar cartilage such as collagen degradation and tiny fissure formation, and this technique is of potential value to clinical application.