Synthesis and Application of Dendriticlinear Polymer PAMAM-Si for Leather Fatliquoring Process

Content: Environmental pollution caused by leather making is the primary concern in the development of leather industry. The use of safe, effective and multi-functional green chemical products has the advantages of reducing leather operations, increasing chemicals utilization, decreasing the environmental burden, improving leather quality. In this study, dendritic-linear polymers of PAMAM-Si 1G and PAMAM-Si 2G were applied to fatliquoring process, which were prepared by branching polysiloxane on the dendritic polyamide-amine (PAMAM). Then the emulsion properties, fatliquoring properties and fatliquoring mechanism were studied by EDS, SEM, XRD, TG and washing experiments. The conclusion was drawn that PAMAM-Si are weak alkali products with high emulsion stability. The particle size of PAMAM-Si 1G was 35.8 nm, and that of PAMAM-Si 2G was 26.7 nm. They can improve the softness, shrinkage temperature and physical and mechanical properties of leather. The softness of leather with PAMAM-Si 1G and PAMAM-Si 2G increased by 115.6% and 104.7% respectively. The shrinkage temperature of leather with PAMAM-Si 2G increased by 2.9℃. The Breaking elongation of leather with PAMAM-Si 1G and PAMAM-Si 2G increased by 38.6% and 32.4% respectively. At the same time, PAMAM-Si not only increased the distance and disorder of fiber but combined with collagen fiber through hydrogen bond, a certain amount of physical adsorption and covalent bond. Take-Away: 1. The dendritic-linear polymers of PAMAM-Si 1G and PAMAM-Si 2G were prepared by branching polysiloxane on the dendritic polyamide-amine (PAMAM). 2. PAMAM-Si can improve the softness, shrinkage temperature and physical and mechanical properties of leather. 3. PAMAM-Si not only increased the distance and disorder of fiber but combined with collagen fiber through hydrogen bond, a certain amount of physical adsorption and covalent bond

Ambient conditions disordered-ordered phase transition of two-dimensional interfacial water molecules dependent on charge dipole moment

Phase transitions of water molecules are commonly expected to occur only under extreme conditions, such as nanoconfinement, high pressure, or low temperature. We herein report the disordered-ordered phase transition of two-dimensional interfacial water molecules under ambient conditions using molecular-dynamics simulations. This phase transition is greatly dependent on the charge dipole moment, production of both charge values, and the dipole length of the solid surface. The phase transition can be identified by a sharp change in water-water interaction energies and the order parameters of the two-dimensional interfacial water monolayer, under a tiny dipole moment change near the critical dipole moment. The critical dipole moment of the solid material surface can classify a series of materials that can induce distinct ordered phases of surface water, which may also result in surface wetting, friction, and other properties

A Simple Time Domain Collocation Method to Precisely Search for the Periodic Orbits of Satellite Relative Motion

A numerical approach for obtaining periodic orbits of satellite relative motion is proposed, based on using the time domain collocation (TDC) method to search for the periodic solutions of an exact J2 nonlinear relative model. The initial conditions for periodic relative orbits of the Clohessy-Wiltshire (C-W) equations or Tschauner-Hempel (T-H) equations can be refined with this approach to generate nearly bounded orbits. With these orbits, a method based on the least-squares principle is then proposed to generate projected closed orbit (PCO), which is a reference for the relative motion control. Numerical simulations reveal that the presented TDC searching scheme is effective and simple, and the projected closed orbit is very fuel saving

Novel NIR-II organic fluorophores for bioimaging beyond 1550 nm

This work was partially supported by grants from NSFC (81773674, 81573383, and 21473041), NSFHP (2017CFA024, 2017CFB711, and 2016ACA126), the Applied Basic Research Program of WMBST (2019020701011429), Tibet Autonomous Region Science and Technology Plan Project Key Project (XZ201901-GB-11), Project First-Class Disciplines Development Supported by Chengdu University of Traditional Chinese Medicine (CZYJC1903), and Health Commission of Hubei Province Scientific Research Project (WJ2019M177 and WJ2019M178).Peer reviewedPublisher PD

Organic NIR-II dyes with ultralong circulation persistence for image-guided delivery and therapy

Acknowledgments This work was partially supported by grants from the National Key R&D Program of China (2020YFA0908800), NSFC (82111530209, 81773674, 91959103, 81573383, 21763002), Shenzhen Science and Technology Research Grant (JCYJ20190808152019182), the Applied Basic Research Program of Wuhan Municipal Bureau of Science and Technology (2019020701011429), Hubei Province Scientific and Technical Innovation Key Project (2020BAB058), the Local Development Funds of Science and Technology Department of Tibet (XZ202102YD0033C, XZ202001YD0028C), and the Fundamental Research Funds for the Central Universities.Peer reviewedPublisher PD

Identification of Salt Tolerance-related microRNAs and Their Targets in Maize (Zea mays L.) Using High-throughput Sequencing and Degradome Analysis

To identify the known and novel microRNAs (miRNAs) and their targets that are involved in the response and adaptation of maize (Zea mays) to salt stress, miRNAs and their targets were identified by a combined analysis of the deep sequencing of small RNAs (sRNA) and degradome libraries. The identities were confirmed by a quantitative expression analysis with over 100 million raw reads of sRNA and degradome sequences. A total of 1040 previously known miRNAs were identified from four maize libraries, with 762 and 726 miRNAs derived from leaves and roots, respectively, and 448 miRNAs that were common between the leaves and roots. A total of 37 potential new miRNAs were selected based on the same criteria in response to salt stress. In addition to known miR167 and miR164 species, novel putative miR167 and miR164 species were also identified. Deep sequencing of miRNAs and the degradome [with quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses of their targets] showed that more than one species of novel miRNA may play key roles in the response to salinity in maize. Furthermore, the interaction between miRNAs and their targets may play various roles in different parts of maize in response to salinity

Aggregation-Induced Emission (AIE), Life and Health

Light has profoundly impacted modern medicine and healthcare, with numerous luminescent agents and imaging techniques currently being used to assess health and treat diseases. As an emerging concept in luminescence, aggregation-induced emission (AIE) has shown great potential in biological applications due to its advantages in terms of brightness, biocompatibility, photostability, and positive correlation with concentration. This review provides a comprehensive summary of AIE luminogens applied in imaging of biological structure and dynamic physiological processes, disease diagnosis and treatment, and detection and monitoring of specific analytes, followed by representative works. Discussions on critical issues and perspectives on future directions are also included. This review aims to stimulate the interest of researchers from different fields, including chemistry, biology, materials science, medicine, etc., thus promoting the development of AIE in the fields of life and health