Zn/Al-centered tetrahedral framework oxide Ba4Zn2Al2O9

2021 ◽  
pp. 122830
Author(s):  
Rayko Simura ◽  
Kyosuke Sawamura ◽  
Hisanori Yamane
Keyword(s):  
Tetrahedral Framework

Monoclinic and Hexagonal Nepheline Structures of (Na3/4/K1/4)AlGeO4

1998 ◽  
Vol 54 (3) ◽  
pp. 211-220 ◽  
Author(s):  
R. P. Hammond ◽  
J. Barbier
Keyword(s):  
Large Family ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Silicate Mineral ◽  
Tetrahedral Framework ◽  
Space Group ◽  
Cell Parameters ◽  
Monoclinic Form ◽  
Hexagonal Form ◽  
Alkali Atoms

Hexagonal (Na3/4K1/4)AlGeO4 crystallizes in the space group P63 with unit-cell parameters a = 10.164 (2), c = 8.540 (2) Å and Z = 8 [wR(F 2) = 0.066 for all 3060 independent reflections]. Monoclinic (Na3/4K1/4)AlGeO4 crystallizes in the space group P21 with unit-cell parameters a = 10.0477 (4), b = 8.5764 (4), c = 10.2118 (4) Å, β = 119.035 (1)° and Z = 8 [wR(F 2) = 0.120 for all 3194 independent reflections measured on a twinned crystal]. Both structures belong to the large family of stuffed tridymites, with the Al and Ge atoms occupying tetrahedral sites, and the alkali atoms occupying the cavities of the tetrahedral framework. Hexagonal (Na3/4K1/4)AlGeO4 is isostructural with the silicate mineral nepheline (Na3/4K1/4)AlSiO4, while monoclinic (Na3/4K1/4)AlGeO4 corresponds to a minor distortion of the nepheline structure. Chemical analysis by electron microprobe and structure determination of flux-grown single crystals indicate that the hexagonal form with the chemical formula (Na0.78K0.19)Al0.97Ge1.03O4 may be stabilized by an alkali deficiency similar to that found in hexagonal natural nephelines. In contrast, all alkali sites are fully occupied in the monoclinic form of composition (Na0.75K0.25)AlGeO4 and the lower symmetry eliminates the oxygen disorder present in the hexagonal form.

Ca6.3Mn3Ga4.4Al1.3O18—A novel complex oxide with 3D tetrahedral framework

2005 ◽  
Vol 178 (10) ◽  
pp. 3137-3144 ◽  
Author(s):  
Artem M. Abakumov ◽  
Joke Hadermann ◽  
Anna S. Kalyuzhnaya ◽  
Marina G. Rozova ◽  
Mikhail G. Mikheev ◽  
...  
Keyword(s):  
Complex Oxide ◽  
Tetrahedral Framework ◽  
Novel Complex

scholarly journals Self-Assembled Tetrahedral Framework Nucleic Acid Mediated Tumor-Associated Macrophages Reprogramming and Enhancing Cancer Immunotherapy

2021 ◽  
Author(s):  
husun qian ◽  
Yixin Fu ◽  
Minkang Guo ◽  
Wu Yang ◽  
Dian Zhang ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Delivery System ◽  
Signal Pathways ◽  
Tumor Associated Macrophages ◽  
Tetrahedral Framework ◽  
Immunomodulatory Agents ◽  
Cpg Odns ◽  
Targeting Delivery ◽  
M1 Phenotype ◽  
Self Assembled

Abstract There is increasing interest in depleting or repolarizing tumor-associated macrophages (TAMs) to generate a pro-inflammatory effect. However, TAMs usually display an immunosuppressive M2-like phenotype in tumor microenvironment. Apparently, developing a macrophage targeting delivery system with immunomodulatory agents is urgent. In the study, an efficient siRNAs and CpG ODNs delivery system (CpG-siRNA-tFNA) was prepared with nucleic acid stepwise self-assembled. The tFNA composed of CpG ODNs and siRNAs showed a higher stability and an enhanced cellular uptake efficiency. Moreover, the CpG-siRNA-tFNA effectively reprogrammed TAMs toward M1 phenotype polarization with increased pro-inflammatory cytokines secretion and NF-κB signal pathways activation, which triggers dramatical antitumor immune responses. Hence, we have developed an efficient and reliable TAM-targeted therapeutic with immunomodulatory agents for for clinical applications.

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