Improved optical quality of heteroepitaxially grown metal-organic framework thin films by modulating the crystal growth.

Fabricating high-quality thin films of metal-organic frameworks (MOFs) is important for integrating MOFs in various applications. Specifically, optical/electrical devices require MOF thin films that are crystallographically oriented, with closely packed crystals and smooth surfaces. Although the heteroepitaxial growth approach of MOFs on metal hydroxides has been demonstrated to control the orientation of the three crystallographic axes, the fabrication of MOF thin films with both three-dimensional crystallographic orientation and smooth surfaces remains a challenge. In this study, we report the fabrication of high-quality thin films of MOFs with closely packed MOF crystals, smooth surfaces, optical transparency, and crystal alignment by modulating the crystal growth of MOFs using the heteroepitaxial growth approach. High-quality thin films of Cu-paddlewheel-based pillar-layered MOFs are fabricated on oriented Cu(OH)2 thin films via epitaxial growth using acetate ions as modulators to control the crystal morphology. Increasing the modulator concentration results in a uniform crystal shape with a relatively long one-dimensional pore direction and uniform heterogeneous nucleation over the entire film. The MOF thin films fabricated using the modulator exhibit high optical transparency. High-quality MOF thin films with dense and flat surfaces will pave the way for integrating MOFs into sophisticated optical and electrical devices.

Lymph node metastasis is strongly associated with lung metastasis as the first recurrence site in colorectal cancer.

BACKGROUND: The lymphatic system is known to be the primary pathway of metastasis for colorectal cancer. However, beyond regional lymph node metastases, little is known about the pathway of lymphatic metastases and the differences in the recurrence site risk. The aim of this study was to clarify the relationship between lymph node metastasis and the first recurrence site in colorectal cancer. METHODS: Patients with colorectal cancer who underwent curative resection in our institution between January 2003 and December 2016 were included in this analysis. The relationship between the first recurrence site and clinicopathological factors was analyzed by the Cox regression model and competing risk regression model. RESULTS: In total, 1,249 patients with colorectal cancer were included in this analysis. We found that the stages of lymph node metastases (N0 vs N1: P = .008, N0 vs N2a: P < .001, N0 vs N2b: P < .001) were significantly associated with lung metastasis in the multivariate analysis. Furthermore, in the competing risk analysis, the stages of lymph node metastases were significantly correlated with lung metastasis (N0 vs N1: P = .002, N0 vs N2a: P < .001, N0 vs N2b: P < .001) but were not correlated with other recurrence sites. CONCLUSION: The severity of lymph node involvement had a strong correlation with lung metastases in patients with colorectal cancer.