Polymerization-induced emission and selective detection to Fe3+/ Fe2+ of triazine-containing polyureas.

In this study, four polyureas with triazine moiety (PUAs) were successfully synthesized through the polymerization of triazine-containing diamine and diisocyanate. The intramolecular aggregation of triazine rings and urea groups along the macromolecular backbone gives PUAs a significant polymerization-induced emission (PIE). Among the four PUAs, PUA-LP shows a significant fluorescent emission at 450 nm, compared to non/weak fluorescent 2,4-diamino-6-phenyl-1,3,5-triazine and L-Lysine diisocyanate ethyl ester monomers. Additionally, the external factors such as solution concentration, excitation wavelength, and precipitants also play a crucial role in the fluorescence of PUAs. As expected, PUA-LP can selectively recognize and detect Fe3+/Fe2+ ions even in the presence of 12 other metal ions and 10 anions. The limit of detection of PUA-LP to Fe3+/Fe2+ is as low as 1.02 µM (0.06 mg/L) and 0.86 µM (0.05 mg/L), respectively, and far below 0.3 mg/L of the allowable national standard for drinking water by WHO. Furthermore, the quenching mechanism of Fe3+/Fe2+ to PUA-LP is attributed to static quenching caused by the coordination of Fe3+/Fe2+ ions with a coordination ratio of 2:1. Based on PIE, the fluorescent PUA-LP was made into an observable and portable testing paper for detecting Fe3+/Fe2+ ions. Finally, we measured the recovery rate of the actual tap water samples and compared the performance of PIE-active PUA-LP with the other reported fluorescent probes to Fe3+/Fe2+ ions.

Morpholine-modified polyacrylamides with Polymerization-Induced emission and its specific detection to Cu2+ ions.

In this work, three morpholine-modified polyacrylamide derivatives (MMPAm) were successfully prepared by free radical polymerization of monomers with morpholine moiety. The intramolecular aggregation of morpholine rings on macromolecular backbone gives MMPAm a significant polymerization-induced emission (PIE). Particularly, poly(N-morpholine acrylamide) (PNMPA) has the characteristics of strong fluorescence at 450 nm, and its fluorescence quantum yield reaches 2.87 %. The introduction of morpholine moiety, the length of CH2 spacer between morpholine ring and the backbone and the molecular weight play the important roles in PIE properties of PNMPA. Interestingly, PNMPA can recognize and detect Cu2+ specifically even in the presence of 12 other metal ions by thorough fluorescence quenching, and the detection limit of PNMPA is 17.3 µM. Furthermore, the dynamic quenching of PNMPA by Cu2+ ions and the complexation ratio of 1:2 according to JOB's working diagram were confirmed by fluorescence titration. Under the assistance of EDTA, a reversible detection system for Cu2+ is achieved, and a portable test paper from PNMPA for the detection of Cu2+ was also made. In conclusion, PNMPA is endowed with a significant PIE effect by the intramolecular aggregation of morpholine rings along the backbone in the polymerization of non-fluorescent monomer, and is expected to be a promising material for specific detection to Cu2+ ions.

Common Language Development in Multilingual Contexts: A Study of Russian Language Policy in the Early Years of the Soviet Union.

In the field of Russian linguistics, history, and jurisprudence, the Russian language is widely regarded as a political instrument and, to some extent, reflects the development and influence of contemporary language policy of the Russian language in the Soviet Union. This study aims to examine the process, characteristics, influencing psychological and sociological factors, and consequences of Russian language policy in the early Soviet Union (1917-1930s). Thematic analysis and discourse strategy analysis methods were employed to achieve this goal. The results indicate that a well-thought-out language policy necessitates the establishment of language legislation and a precise legal definition of the status and use of different languages. The absence of language legislation can be a major drawback of language policy. While the Soviet Constitution and other relevant political documents broadly define the status and use of Russian and other languages, there is no specific language legislation regulating the use of each language. Analysis of word frequency statistics demonstrates that the key concepts of Stalinist policy differed compared to the time of Lenin's rule, resulting in a lack of effective legal force and strong mechanisms for controlling language policy practices. As the functional advantages of the Russian language become increasingly evident, some ethnic minorities tend to lean towards studying and using it, leading to the emergence of many bilingual and even trilingual individuals. Other minorities with small or underdeveloped populations turn to the Russian language, which is the most widely spoken language. These findings contribute to the theoretical and practical knowledge base for research in the fields of linguistics, linguistic culturology, history, psycholinguistics, and political science. Subsequent research can focus on current aspects of the country's language policy.

Polymerization-induced emission (PIE) of multifunctional polyamides synthesized by Ugi polymerization and targeted imaging of lysosomes.

In this paper, a series of polyamide derivatives (PAMs) containing morpholine groups were prepared by Ugi polymerization from dialdehyde, diacid, N-(2-aminoethyl)-morpholine and isonitrile compounds as novel multi-responsive fluorescent sensors. As non-conjugated light-emitting polymers, PAMs were endowed with unique polymerization-induced emission (PIE) performance at 450 nm by through-space conjugation (TSC) between heteroatoms and heterocycles. It was also found that PAMs exhibited reversible responses to the external temperature and pH values and became responsive fluorescent switches. In addition, PAMs can specifically recognize Fe3+ with a limit of detection (LOD) of 54 nM and the introduction of EDTA reversibly restores the fluorescence of the quenched PAMs-Fe3+ system. By virtue of thermosensitivity, PAMs are easily separated from the above system by changing the temperature above or below the lower critical solution temperature (LCST). It is worth noting that PIE-active PAMs with good biocompatibility can selectively accumulate in lysosomes due to the presence of morpholine groups, and its Pearson colocalization coefficient is as higher as 0.91. Furthermore, a PIE-active PAM was successfully used to track exogenous Fe3+ in lysosomes. In conclusion, these multi-functional PIE-active PAMs have higher potential applications in biomedical or environmental fields.

Corpus-based critical discourse analysis of reporting practices in English news reports on public health event in China and United States.

Introduction: Reporting speech is a basic form of human language, and reporting practices play a key role in news report. As one of the important rhetorical devices to introduce the reported speech, reporting verbs can help the readers understand the source of the reported speech and the attitude of the journalist or the media toward the reported information. Method: This study examines the features of reporting practice in Chinese and American news reports on public health emergency by investigating the use of reporting verbs from the perspectives of critical discourse analysis. Two English news corpora of COVID-19 pandemic are built, namely, the China Daily News Corpus and the New York Times News Corpus, with 50 news texts in each corpus. The corpus analysis tool AntConc 3.3.5 is used to conduct concordance analysis. Results and discussion: It is found that Chinese and American news reports tend to use roughly the same high-frequency reporting verbs in reporting the COVID-19 pandemic. Chinese and American news corpora show difference in the distribution feature of high-frequency reporting verbs in terms of semantic category. Both Chinese and American news reports use speech reporting verbs most frequently, indicating an objective attitude toward the reported event, and use speech reporting verbs and speech act reporting verbs to introduce the reported speech with comparatively higher degree of certainty. American news reports frequently use mental reporting verbs to show the attitude of uncertainty toward the reported speech, and Chinese news reports probably need to raise the awareness of using mental reporting verbs to express the opinions and attitude of the common people or the authority. The findings of this study can provide insights into the research on reporting strategies of news reports on emergencies in China for foreign audience.

The framework and features of language policies in global constitutional texts.

Language policy, which is directly concerned with language practice, language ideology and language management, has become increasingly important in real social life. Explicit language policies in different fields, such as texts in law, education, and the public, have been explored for many years. However, the global comparative research on language policies in various constitutional texts (CT) is quite limited. In response, the present study aimed to investigate the framework and features of language policies in global CT through a combination of qualitative and quantitative analysis. Results showed that: 1) there were seven parts of the CT dealing with language policies, such as Preamble, General principle, The state, Fundamental rights and Duties of citizen, State authority, National objectives, and Supplementary; 2) there existed significant differences in the frequency of language policies in seven parts of the CT. Among them, language policies appeared most frequently in the part of Fundamental rights and duties of citizen; 3) the geographical location where the Constitution was enacted affected the distribution of language policies across parts. Overall, our findings suggested that the language policy in CT was influenced not only by constitutional principles, but also by the national language environment.

Facile Synthesis and Properties of Multifunctionalized Polyesters by Passerini Reaction as Thermosensitive, Biocompatible, and Triggerable Drug Release Carriers.

We developed a facile synthesis for a series of multifunctionalized polyesters by Passerini three-component polymerization (Passerini-3CP) in a "one-pot" method at room temperature using serial dicarboxylic acids, dialdehyde, and tert-butyl isocyanide as monomers. First, the effects of monomer feed ratio, monomer concentration, and different dicarboxylic acids involved in the polymerization were systematically investigated. The in situ FTIR and GPC measurements have suggested a step-growth mechanism for Passerini-3CP. Second, five succinic acid end-capped polyethylene glycols (S-PEGs) with different molecular weights of 400, 800, 1000, 2000, and 4000 g/mol were prepared and selected as dicarboxylic acids for the subsequent Passerini-3CP to fabricate the thermosensitive and biocompatible polyesters. Among the five resulting polyesters, four polyesters from S-PEG-400, S-PEG-800, S-PEG-1000, and S-PEG-2000 show reversible response to the external temperature, and the lower critical solution temperature (LCST) in water is in the range of 28.5-84.2 °C. Through the copolymerization of S-PEG-400 and S-PEG-800, the LCSTs for functional polyesters can be conveniently controlled to be 38.7, 42.3, and 58.0 °C, respectively. After 24-72 h of incubation in polyester solution, the viability rate of HeLa cells reached up to 80-107%, showing its excellent biocompatibility. The cleavable polyesters were also prepared by integrating S-S bonds onto their backbones in Passerini-3CP of 3,3'-dithiodipropionic acid as one comonomer for the biomedical applications. With the aid of the hydrophobicity of doxorubicin (DOX) and thermosensitivity of polyesters, the doxorubicin-loaded carriers with the size of 200-400 nm and core-shell structure were easily obtained by dialysis below LCST and subsequent heating to LCST. The effective release of DOX from the carriers can be triggered by the characteristic reaction of l-glutathione (GSH) with S-S bonds in the functionalized polyester backbones.