The Effect of Substituent Position on Excited State Intramolecular Proton Transfer in Benzoxazinone Derivatives: Experiment and DFT Calculation.

The preparation and the photophysical behaviour of two benzoxazinone derivatives isomers 2-(1-hydroxynaphthalen-2-yl)-4H-benzo[e][1, 3]oxazin-4-one(1) and 2-(3-hydroxynaphthalen-2-yl)-4H-benzo[e][1, 3]oxazin-4-one(2) designed for displaying were reported. The effect of substituent position and solvent effect on the excited state intramolecular proton transfer (ESIPT) dynamics and the spectroscopic properties were investigated using a combined theoretical (i.e., time-dependent density function theory (DFT)) and experimental (i.e., steady-state absorption and emission spectra and time-resolved fluorescence spectra) study. The results showed that compound 1 would facilitate ESIPT process and favored the keto tautomer emission, while compound 2 suppressed the ESIPT process and favored the enol emission.

[The effect of compressive stress on the factors for liver regeneration in hepatocytes Chang cell line].

OBJECTIVE: To investigate the effect of compressive stress on the factors for liver regeneration including NF-kappaB, signal transducers and activators of transcription 3 (STATS), c-fos and c-jun in hepatocytes Chang cell line. METHODS: Human hepatocytes Chang cell line were subjected to compressive stress at 1000 microstain or 2000 microstain, expression of NF-kappaB P65, p-STAT3, c-fos and c-jun were detected by Western blot or RT-PCR at 30 min, 1 h, 2 h, 3 h, 4 h, 6 h after application of compressive stress to indicate the priming of hepatocytes proliferation. RESULTS: Enhanced expressions of NF-kappaB P65 and p-STAT3 were observed in hepatocytes under compressive stress indicated by Western blot, the magnitude of compressive stress loaded significantly affected the level of expression of NF-kappaB P65 at 2 h (P = 0.046) and p-STAT3 at 1 h (P = 0.039), the peak of expression of p-STAT3 was at 30 minutes after stress-loading while NF-kappaB P65 was at 1 hour; RT-PCR showed that expression of c-fos was not significantly different between 1000 microstain and 2000 microstain at each time point, and expression of c-jun was significantly different at 30 minutes (P = 0.026), 1 h (P = 0.031), 2 h (P = 0.033) after compressive stress loading. CONCLUSION: These results indicate that compressive stress may play an important role in initiating the process of liver regeneration.

2,3,4,5-Tetraphenylsilole-based conjugated polymers: synthesis, optical properties, and as sensors for explosive compounds.

A series of linear 2,5-tetraphenylsilole-vinylene-type polymers were successfully synthesized for the first time. The tetraphenylsilole moieties were linked at their 2,5-positions through a vinylene bridge with p-dialkoxybenzenes to obtain polymer PSVB and with 3,6-carbazole to obtain polymer PSVC. For comparison, 2,5-tetraphenylsilole-ethyne-type polymer PSEB was also synthesized, in which the vinylene bridge of PSVB was replaced with an ethyne bridge. Very interestingly, the bridging group (vinylene or ethyne) had a significant effect on the photophysical properties of the corresponding polymers. The fluorescence peak of PSEB at 504 nm in solution originated from the emission of its silole moieties, whereas PSVB and PSVC emitted yellow light and no blueish-green emission from the silole moieties was observed, thus demonstrating that the emissions of PSVB and PSVC were due to their polymer backbones. More importantly, the 2,5-tetraphenylsilole-ethyne polymer exhibited a pronounced aggregation-enhanced emission (AEE) effect but the 2,5-tetraphenylsilole-vinylene polymer was AEE-inactive. Moreover, both AEE-active 2,5-tetraphenylsilole-ethyne polymer and AEE-inactive 2,5-tetraphenylsilole-vinylene polymers were successfully applied as fluorescent chemosensors for the detection of explosive compounds.