ABSTRACT
Here, we reported the crystal structures, dielectric and conducting properties of two Schiff base iodide compounds [m-BrBz-1-APy]I3 (1) and [o-FBz-1-APy]I3 (2). The Schiff base cations build irregular channel frameworks, and the polyiodide anions are located in the channel. The impedance spectra demonstrated that the two compounds show intrinsic iodide ion conductance with higher conductivity of 1.03(4) × 10-4 S cm-1 at 343 K for 1 and 4.94(3) × 10-3 S cm-1 at 353 K for 2. The dielectric modulus analysis further confirmed that the conductance contributed to the migration of iodide ions.
ABSTRACT
Here, we report the crystal structures, phase transitions, and thermal, dielectric, and conducting properties of an ion-pair compound [C4-bmim][Ni(mnt)2] (1). 1 undergoes a three-step phase transition with four phases before melting. A two-step dielectric constant bistability is also realized by the structural phase transition in 1 occurring among phases I, II, and III, which is due to the in-plane oscillations of the alkyl chain and crystal-to-mesophase transition, respectively. Moreover, 1 exhibits rare temperature-dependent conducting properties accompanying structural phase transitions, and conductivity is very high with 0.00186 S cm-1 at 413 K. The conduction properties of phase III (mesophase) arise from the dipole molecular motion.
ABSTRACT
Chair 3D Co(II) phosphite frameworks have been prepared by the ionothermal method. It belongs to chiral space group P3221, and the whole framework can be topologically represented as a chiral 4-connected qtz net. It shows a multistep dielectric response arising from the reorientation of Me2-DABCO in the chiral cavities. It can also serve as a pron conductor with high conductivity, 1.71 × 10-3 S cm-1, at room temperature, which is attributed to the formation of denser hydrogen-bonding networks providing efficient proton-transfer pathways.
ABSTRACT
A three-dimensional metal-organic framework compound [NH2(CH3)2]2[Zn3(bpdc)4]·3DMF (1) shows two step dielectric relaxation and its guest-free framework (1') possesses an ultra-low κ value of 1.80 (at 100 kHz, it is the lowest value for MOFs reported to date) over a wide temperature range and high thermal stability.
ABSTRACT
The mammalian cyclin-dependent kinase subunit (Cks) family has two members, Cks1 and Cks2. Overexpression of Cks1 and Cks2 has been reported to be associated with high aggressiveness and poor prognosis in several malignancies, including prostate and hepatocellular carcinomas. However, whether Cks1 and Cks2 are overexpressed in esophageal carcinoma remains uncharacterized. To investigate whether overexpression of the Cks family is clinically relevant in esophageal carcinoma, and whether expression patterns of Cks1 and Cks2 can serve as biomarkers for esophageal carcinoma. Real-time quantitative reverse transcription polymerase chain reaction, immunohistochemistry, and Western blot analyses were applied to detect the expression of Cks1 and Cks2 at the mRNA and protein levels, respectively. The associations between Cks1 or Cks2 expressions and clinical features and p27(kip1) expressions in esophageal carcinoma were analyzed. Comparing with the adjacent noncancerous tissues, esophageal carcinoma exhibited elevated expression of Cks1 in 58% cases at the mRNA level and 54% cases at the protein level, and elevated expression of Cks2 in 65% cases at the mRNA level and 61% cases at the protein level, respectively. The expressions of both Cks1 and Cks2 were negatively associated with the p27(kip1) protein level in the tumor tissues. Furthermore, overexpression of Cks1 and Cks2 in esophageal carcinoma was closely associated with poor pathological features of esophageal carcinoma, including higher histologic grade of tumor, regional lymph nodes invasion, and neoplastic embolus. Overexpression of Cks1 and Cks2 is associated with the aggressive tumor behaviors of esophageal carcinoma. Further efforts are needed to determine whether overexpression of Cks1 and Cks2 can serve as novel biomarkers for esophageal carcinoma.