Synthesis and controlled radical polymerization of multifunctional monomers

Multifunctional monomers on the basis of acryl- and methacryl derivatives were synthesized and different protective groups were used. After polymerization the protective groups were removed by different methods. Various initiators for the NMP of the monomers were synthesized and the reaction conditions were optimized. The results showed that NMP was not a suitable method for multifunctional acryl- and methacryl derivatives to achieve well-defined homopolymers, although it was successful for control of polymerization of styrene and block copolymerization of multifunctional acryl- and methacryl derivatives with alkoxyamine terminated polystyrene. The ATRP of multifunctional acrylates and methacrylates has been successfully performed, as well as the block copolymerization of multifunctional acrylates and methacrylates. Relatively low polydispersities of the corresponding polymers (PD=1.18-1.36) and reasonably high rates of polymerization could be achieved when Me6TREN and PMDETA were used as ligands. However, the ATRP of multifunctional acrylamides and methacrylamides failed. The RAFT-polymerization of styrene, acrylamide and acrylate using BDTB as a CTA and AIBN as an initiator afforded polymers with narrow molecular weight distribution (PD=1.13-1.26). A kinetic investigation and the further synthesis of block copolymers using dithioester-terminated homopolymers as macroCTAs showed that the RAFT polymerization of acrylamide M9b proceeded in a living manner. However, BDTB does not control the reaction of methacrylic monomers, such as methacrylates and methacrylamides. The bulk phase behavior of the block copolymers were examined by means of DSC and the surface behaviors of block copolymers as thin layers were examined with AFM. Two-phase transitions in the block copolymers were observed clearly by DSC, indicative of the appearance of phase separations, which were seen in an AFM image. In conclusion, multifunctional acryl- and methacryl derivatives failed to achieve well-defined homopolymers by NMP. However, this method was successful for block copolymerization of multifunctional acryl- and methacryl derivatives with alkoxyamine terminated polystyrene. Multifunctional acrylates and methacrylates were successfully homopolymerized and block copolymerized by ATRP. Multifunctional acrylates and acrylamides were suitable for homopolymerization and block copolymerization by the RAFT process. Thus far, it is difficult to homopolymerize multifunctional methacrylamides in controlled way

Construction of a Credit System in the International Trade of Small Commodities: The Case of Yiwu

In Yiwu, Arabic commercial activities and their credit trade model serve as a case for exploring cross-cultural communication issues in the credit system. As the study reveals, shared social network and long-term communication are essential for a cross-cultural credit system. To solve trade disputes, however, requires government’s support and social organizations’ participation

Nanoscaled Fluorescent Films and Layers for Detection of Environmental Pollutants

Hazardous gas and ion pollutants are the most serious environmental problems around the world. It is of great importance to develop devices for easy detection of these hazardous substances. Fluorescence technology with high resolution and operational simplicity has attracted a lot of attention in recent years. Organic fluorescent dyes absorb/emit lights within a broad wavelength range, which is suitable for various demands. Chromophores, such as perylene, cyanine dyes, spiropyran, and so on, are widely studied as fluorescent probes for gases and ions. The dyes could respond to external stimuli through structural changes of the conjugated chromophore itself or the attached functional groups, leading to detectable spectral changes. Organic dyes are incorporated into nanoscaled films and layers, which are portable and durable for effective sensing in complex environments. In this chapter, preparation and application of fluorescent films and layers (FFL) for gaseous/ionic detection are reviewed. We discuss the response mechanism of fluorescent dyes, the fabrication of nanoscaled FFL, and some examples of FFL for the detection of gas and ion pollutants

Amphiphilic Ionic Perylenediimides: Structures, Self-Assembly Studies and Biomedical Applications

Amphiphilic ionic perylenediimides (AIPDIs) with well‐defined structures have been widely studied, which involve abundant non‐covalent interactions. Among these interactions, electrostatic interactions serve as the primary force that may be followed by other non‐covalent interactions like π–π stacking. Taking advantage of these tunable interactions between simple AIPDI‐building blocks, AIPDIs are widely used for constructing increasingly complex structures at varying scales. Besides, AIPDIs with outstanding photochemical stability exhibit high fluorescence quantum yields (FQYs) in aqueous solution, because hydrophilic substituents of AIPDIs can shield the inner perylene chromophores and weaken π–π stacking, contributing to the improvement of water solubility and the suppression of aggregation‐caused quenching (ACQ). AIPDIs with excellent water solubility, strong FQYs and desired interactions with charged components in cells and tissues hold great promise for various biomedical applications, which can be concluded in three hierarchical levels, which is in vitro, live cell and tissue

Validation of Suitable Reference Genes for Quantitative Gene Expression Analysis in Panax ginseng

Reverse transcription-qPCR (RT-qPCR) has become a popular method for gene expression studies. Its results require data normalization by housekeeping genes. No single gene is proved to be stably expressed under all experimental conditions. Therefore, systematic evaluation of reference genes is necessary. With the aim to identify optimum reference genes for RT-qPCR analysis of gene expression in different tissues of Panax ginseng and the seedlings grown under heat stress, we investigated the expression stability of eight candidate reference genes, including elongation factor 1-beta (EF1-β), elongation factor 1-gamma (EF1-γ), eukaryotic translation initiation factor 3G (IF3G), eukaryotic translation initiation factor 3B (IF3B), actin (ACT), actin11 (ACT11), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and cyclophilin ABH-like protein (CYC), using four widely used computational programs: geNorm, Normfinder, BestKeeper, and the comparative ΔCt method. The results were then integrated using the web-based tool RefFinder. As a result, EF1-γ, IF3G and EF1-β were the three most stable genes in different tissues of P. ginseng, while IF3G, ACT11 and GAPDH were the top three-ranked genes in seedlings treated with heat. Using three better reference genes alone or in combination as internal control, we examined the expression profiles of MAR, a multiple function-associated mRNA-like non-coding RNA (mlncRNA) in P. ginseng. Taken together, we recommended EF1-γ/IF3G and IF3G/ACT11 as the suitable pair of reference genes for RT-qPCR analysis of gene expression in different tissues of P. ginseng and the seedlings grown under heat stress, respectively. The results serve as a foundation for future studies on P. ginseng functional genomics

Sentiment Analysis and Topic Modeling Study: The Comparison of Cosmetics Product Online Reviews

In the competition, companies must orient themselves to serve clients, engage with rivals, and launch products to build a dynamic and competitive corporate environment. The need to meet basic requirements such as clothes, food, and boards, which were formerly straightforward, became increasingly complicated. This can be proven by the development of the cosmetic industry which is marked by the variety of cosmetics on the market. There is currently a need for brand comparison in the business competition since it can make it simpler to understand the strengths and weaknesses of rival companies and serve as a model for enhancing the quality of well-liked items and marketplaces. Indonesia is a very attractive cosmetic market where cosmetic sales data are consistently rising from year to year. Due to the rapid advancement of information technology, buyers now write reviews on social media in addition to conducting online shopping. These online reviews can be helpful for comprehending the shopping process and discussing a product, and affect the customer's plans to make additional purchases in the future. This study compared customer perception of three cosmetics products: powder foundation products from local brands that are Make Over Powerstay Matte Powder Foundation, ESQA Flawless Powder Foundation, and Luxcrime Blur&Cover Two Way Cake, using an online review that was extracted and scraped from a website through the Octoparse Windows program version 8.5.0. This study uses sentiment analysis and topic modeling to compare online reviews of customer perceptions of the three cosmetic products. The result shows the sentiment comparison among three cosmetics brands. The first position is the ESQA brand, followed by the Luxcrime brand, and the last rank is Make Over, with the smallest positive sentiment. The positive brand topics of the three products, in general, are about formulas that are long-lasting and have good coverage, while the negative brand topics, in general, are about formulas that must be reused and transferred when wearing masks

Arab Traders Pursuing Chinese Dream in East China

The rise of Arab traders from the Middle East and North Africa in Yiwu, a county-level city in Zhejiang Province, the People's Republic of China, has received unprecedented media attention in the context of the Belt and Road initiative. The resident population of Arab traders was over 4,000 in 2016, attracted to the world largest petty commodities wholesale marketplace in the city and were mainly engaged in exporting commodities back to their home countries. Little academic attention has been given to the Arab traders' life and business in China. This is an ethnographic study of Arab traders' engagement in producing power and building cross-cultural trust in their host society. It examines what attracts Arab entrepreneurs to Yiwu, their role in building multinational trading networks, and their increasingly diverse modes of interaction with the majority Chinese community. Drawing on twelve months' fieldwork from November 2015 to December 2016 and follow-up research in November 2017 and February 2019, this project highlights foreign migrant entrepreneurial communities in China, the informal economy and low-end globalization. It shows how Arab traders establish cross-cultural trust with their Chinese partners to maintain a transnational trading system, and outline what their social and business interactions tell us about migrant entrepreneurship and interracial dynamics in China. The ethnographic findings reveal that Arab traders operate and facilitate their transnational business using various kinds of social capital. Many were expatriated by their families and were based in China; this being considered the most stable group of Arab traders by potential Chinese partners. A few were students who had become intermediaries, having studied in Chinese universities and subsequently worked for Arab buyers. The third group were fortune seekers, who presence in the marketplace as shuttle-travelers were considered the most unstable partners for Chinese business people. Arab traders redefined the power relationships in the market. They bought products on credit and forced Chinese suppliers to accept their trading patterns. When married to Chinese women, Arab husbands also required their wives to convert to Islam and subordinate their own culture to their husbands to maintain to maintain their affective relationship. By producing power over other groups, Arab traders transforms their marginal and powerless status in the host society. The presence of Arab traders also influenced the labor market. They integrated Hui migrant Muslims, who can speak Arabic, into export industries to work as interpreters. These Hui people held a dominant role in export industries reversing the general characterization of Chinese minorities being at a disadvantage in the job market. Arab traders regulated the Hui migrant Muslims by spiritual means (e.g. how to be good Muslim, as the traders saw it) rather than control their laborers by more the typical means seen in China. This study aims to deepen our knowledge of small-scale foreign traders in China. Through discussing the process of building trust among different groups, it provides an opportunity to observe cross-cultural communication in detail and in practice