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  1. Free, publicly-accessible full text available May 9, 2024
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  3. Abstract

    Alloying selected layered transitional metal trichalcogenides (TMTCs) with unique chain‐like structures offers the opportunities for structural, optical, and electrical engineering thus expands the regime of this class of pseudo‐one‐dimensional materials. Here, the novel phase transition in anisotropic Nb(1−x)TixS3alloys is demonstrated for the first time. Results show that Nb(1−x)TixS3can be fully alloyed across the entire composition range from triclinic‐phase NbS3to monoclinic‐phase TiS3. Surprisingly, incorporation of a small concentration of Ti (x ≈0.05–0.18) into NbS3host matrix is sufficient to induce triclinic to monoclinic transition. Theoretical studies suggest that Ti atoms effectively introduce hole doping, thus rapidly decreases the total energy of monoclinic phase and induces the phase transition. When alloyed, crystalline and optical anisotropy are largely preserved as evidenced by high resolution transmission electron microscopy and angle‐resolved Raman spectroscopy. Further Raman measurements identify Raman modes to determine crystalline anisotropy direction and offer insights into the degree of anisotropy. Overall results introduce Nb(1−x)TixS3as a new and easy phase change material and mark the first phase engineering in anisotropic van der Waals (vdW) trichalcogenide systems for their potential applications in two‐dimensional superconductivity, electronics, photonics, and information technologies.

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  4. Abstract

    Patients with metastatic triple‐negative breast cancer (TNBC) have a poor prognosis, so new therapies or drug combinations that achieve more effective and durable responses are urgently needed. Here, a combination therapy using cowpea mosaic virus (CPMV) and low doses of cyclophosphamide (CPA) is developed with remarkable synergistic efficacy against 4T1 mouse tumors in vivo. The combination therapy not only attenuates the growth of primary tumor and increases survival, but also suppresses distant tumor growth and reduces lung metastasis. Mechanistic analysis indicates that the combination of CPMV and CPA increases the secretion of several cytokines, activates antigen‐presenting cells, increases the abundance of tumor infiltrating T cells, and systematically reverses the immunosuppression. These results show that the combination of CPMV in situ vaccination with chemotherapy may become a potent new strategy for the treatment of TNBC.

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  5. Abstract

    Large‐scale synthesis of van der Waals (vdW) metal–organic framework (MOF) nanosheets with controlled crystallinity and interlayer coupling strength is one of the bottlenecks in 2D materials that has limited its successful transition to large‐scale applications. Here, scalable synthesis of mBDC (m = Zn and Cu) 2D MOFs at large scales through a biphase method is demonstrated. The results show replacing water molecules with pyridine eliminates hydrogen bond formation at metal cluster sites. This prohibits tight coupling across adjacent MOF layers and sustains controllable 2D vdW MOF growth. It is further shown that control over the growth speed, crystallinity, and thickness can be achieved by addition of a controlled amount of triethylamine and formic acid to achieve highly crystalline vdW MOF nanosheets with extraordinarily high aspect ratio. The described synthesis route can easily be scaled up for large‐scale production either by deposition onto desired substrates or in crystalline layered powder form. Owing to its large lateral size, vdW nature, and high crystallinity, it is possible to perform atomic force microscopy, Kelvin probe force microscopy, and Raman measurements on the 2D MOFs. The results not only establish their vibrational properties and layer‐dependent responses but also show striking differences from other 2D inorganic materials.

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