Abstract Although the syntheses and applications of rhodamine dyes have been extensively researched, the photophysical properties and photostability have rarely been studied. In this study, we systematically investigated the photophysical properties and photostability of six rhodamine dyes by the spectrum measurements, photodegradation experiments and theoretical calculations. It was found that the following structural modifications can lead to the redshift of absorption and fluorescence emission spectra: Increasing the alkyls of amino on xanthene; forming rigid ring between the N-linked alkyl and xanthene; esterification of –COOH on benzene ring. The degradation experiments under 525 nm light irradiation indicated that increasing the alkyls of amino on xanthene improves the photostability, fixing the N-linked alkyls on the xanthene ring to form rigid rings would significantly reduce the photostability of rhodamine dyes, and the esterification of –COOH on benzene ring can increase the photostability to some extent. The results of DFT calculations showed that the esterification of − COOH decreases the dihedral angle D 1 and increases D 2 , the variation trend of calculated absorption and emission wavelengths is consistent with the measured results, and the rhoodamine dyes with higher electrophilic index usually have higher photostability.
Light-induced drift has many applications in astrophysics, semiconductor physics, and isotope separation. Light-induced drift velocity is a key parameter to characterize the effect of light-induced drift. Laser linewidth exerts a great influence on light-induced drift velocity through influencing the velocity selectivity of atomic excitation, so it is an important factor that cannot be ignored in the study of light-induced drift. However, in existing theoretical studies, the influence of laser linewidth is seldom considered and the exciting light is always treated as monochromatic light. Furthermore, in a few theoretical studies about laser linewidth, the numerical model adopted does not include all the factors of light-induced drift, such as energy level degeneracy, hyperfine structure, and collision model, which will cause the error of calculation. In order to study the influence of laser linewidth on light-induced drift velocity, a four-level rate equation model is established to describe the atomic energy level transition in the process of light-induced drift. In the theoretical model, we introduce strong collision model to describe collisions between atoms and buffer gas. The influences of energy level degeneracy and hyperfine structure are also taken into account. Numerical method is used to calculate the four-level rate equation. According to the calculation results, the influence of laser linewidth on drift velocity of alkali metal atoms is analyzed. The results show that as the linewidth increases, the value of drift velocity first increases and then decreases. There is an optimal linewidth that maximizes the drift velocity. For the best light-induced drift effect, the laser should work under the optimal linewidth condition. When the laser linewidth fluctuates near the optimum linewidth, the laser linewidth should be set to be slightly wider than the optimal linewidth. This can reduce the influence of fluctuation and obtain a better drift effect. In addition, as the laser linewidth increases, the optimum power density corresponding to the maximum drift velocity decreases. When the laser linewidth is narrow, small fluctuations near the optimal laser power density will not have great influence on drift velocity. When the laser linewidth is wide, the power density should be set strictly. The optimum linewidth is related to laser power density, temperature and buffer gas pressure. As the laser power density increases, the value of optimum linewidth first increases rapidly and then decreases slowly. The value of optimal linewidth also increases linearly with the increase of temperature, and it decreases with the increase of buffer gas pressure. In conclusion, the laser linewidth does play a key role in the process of light-induced drift. The results of this study can provide a theoretical basis for future experiments, and be a good reference to the selection of exciting light.
Abstract The current mainstream planar X‐ray imaging techniques face significant challenges for accurately capturing the internal structure of curved objects, since the variable distances between the curved objects and the flat‐panel scintillation screen cannot eliminate the distortion in X‐ray imaging. Though large‐area and transparent curved scintillation screens are much more desirable. Here, organic–inorganic hybrid Mn‐based single crystals ([CH 3 Ph 3 P] 2 MnX 4 , X = Cl, Br, I) exhibiting high photoluminescence quantum yield (PLQY) and low melting temperature have been employed to prepare transparent glass for X‐ray scintillation imaging application through a low‐temperature melting strategy. The [CH 3 Ph 3 P] 2 MnBr 4 ‐glass shows high PLQY (47.8%), high‐resolution X‐ray imaging performance (12.3 lp mm −1 ), low limit of detection (25.33 nGy s −1 ), and impressive X‐ray irradiation stability (102 Gy). Furthermore, high‐contrast X‐ray imaging at a low dose (6.865 µGy per exposure, 14.5 times lower than the chest radiograph) is achieved. Based on the low glass transition temperature ( T g = 53.6 °C) and easy‐shapeable properties of [CH 3 Ph 3 P] 2 MnBr 4 ‐glass scintillator, the large‐area curved scintillation screen with a series of sizes of Φ 2×4 – Φ 8×4 cm 2 can be easily fabricated and show high X‐ray imaging quality. These findings provide a paradigm for future research in shapeable X‐ray scintillators, unlocking new possibilities for curved and 3D X‐ray imaging.
A study has been made about the removal effect of Reactive Light Yellow X-6G from wastewater with a process of anaerobic(a themophilic up-flow anaerobic sludge blanket(UASB) reactor at 55℃ / aerobic(a mesophilic three-phase aerobic biological fluidized bed reactor).Experiment results show that at 55 ℃ of water temperature,water operation cycle is 120 days and when the HRT is 18hr,the removal rate is 80%～90% for dyes and CODCr with CODCr at 600～1000mg/L,salt(NaCl)25～35mg/L and Active Bright Yellow X-6G density 40～50mg/L.
A series of alkaline earth metal fluorooxoborates, MB4O6F2 (M = Ca, Sr, Ba) with functional [B4O6F2]∞ groups, have been synthesized. The diffuse-reflectance spectra measurements indicate that the cutoff edges of title compounds are below 190 nm. Moreover, the first-principle calculation results demonstrate that MB4O6F2 (M = Ca, Sr, Ba) have large birefringence of 0.091, 0.089 and 0.085 at 1064 nm. Both experimental and theoretical studies suggest that MB4O6F2 (M = Ca, Sr, Ba) are promising birefringent materials for deep-UV applications. For more information, see the Communication by y. Wang, S. Pan et al. on page 11267 ff.
Abstract The incidence and development of various tumors, such as hepatocellular carcinoma (HCC), are linked to tumor stem cells. Although research has revealed how important SCL/TAL1 interruption site (STIL) is in many human tumors, the impact of STIL on HCC stem cells is poorly understood. This study aimed to examine the regulatory mechanisms and the function of STIL in the stemness of HCC tumor cells. Bioinformatics analysis was applied to determine the STIL and regulatory factor X‐5 ( RFX5) expression in HCC tissues. Immunohistochemistry (IHC) was used to detect the expression of STIL and RFX5 in HCC tissues. Quantitative real‐time polymerase chain reaction was utilized to measure the STIL and RFX5 expression levels in HCC cells. The viability of the cells was assessed by the Cell Counting Kit‐8 assay. The sphere formation assay was used to evaluate the sphere‐forming capacity. The expression levels of the stem cell markers SOX2, Oct‐4, CD133, CD44, the glycolysis‐related proteins LDHA, HK2, AKT, p‐AKT, and β‐catenin were assessed by Western blot. Lactate production, oxygen consumption rate, and extracellular acidification rate were measured to assess the glycolytic capacity of HCC cells. Chromatin immunoprecipitation and dual‐luciferase experiments were performed to validate the connection between RFX5 and STIL. Bioinformatics analysis determined that STIL exhibited high expression in HCC tissues and was enriched in the glycolysis pathway. In addition, the expression of glycolysis marker genes was positively correlated with STIL expression. Cell experiments verified that the activation of the glycolysis pathway by overexpression of STIL promoted stemness in HCC. Molecular experiments also revealed the binding relationship between STIL and RFX5 . IHC detected high expression of STIL and RFX5 in HCC tissues. Cell functional experiments revealed that RFX5 could influence the HCC cells stemness by activating the STIL transcription via the glycolysis pathway. This study identified a novel role for the RFX5/STIL axis in HCC progression, which may offer treatment targets for HCC.
A new alkaline-earth fluorooxoborate, BaB8O12F2, has been discovered through chemical substitution of a cation. It exhibits a short cutoff edge and a large birefringence.
A water-based detergent for printing ink was prepared successfully to substitute gasoline,kerosene,and emulsified oil for cleaning of printing roller and mackintosh,and this detergent is safety and energy saving.The raw material were prepared,and then mixed with water in proportion of 1 ∶9.The raw material include: TrionX-100(15%),sodium oleate(60%),tributyl phosphate(5%),butyl alchohol(15%),sodium nitrite(4.5%),and benzotriazole(0.5%) etc..The experimental result showed that the cleaning capability of the water-based detergent for printing ink is as much as the gasoline,kerosene and emulsified oil.This detergent doesn't corrode facilities,not flashes,and its applied effect is very good.
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