Fluorescent Polylactic acid composite incorporating lignin-based carbon quantum dots for sustainable 4D printing applications.

Fluorescent 4D printing materials, as innovative materials that combine fluorescent characteristics with 4D printing technology, have attracted widespread interest and research. In this study, green lignin-derived carbon quantum dots (CQDs) were used as the fluorescent module, and renewable poly(propylene carbonate) polyurethane (PPCU) was used for toughening. A new low-cost fluorescent polylactic acid (PLA) composite filament for 4D printing was developed using a simple melt extrusion method. The strength of the prepared composite was maintained at 32 MPa, while the elongation at break increased 8-fold (34 % increase), demonstrating excellent shape fixed ratio (∼99 %), recovery ratio (∼92 %), and rapid shape memory recovery speed. The presence of PPCU prevented fluorescence quenching of the CQDs in the PLA matrix, allowing the composite to emit bright green fluorescence under 365 nm ultraviolet light. The composite exhibited shear thinning behavior and had an ideal melt viscosity for 3D printing. The results obtained demonstrated the versatility of these easy-to-manufacture and low-cost filaments, opening up a novel and convenient method for the preparation of strong, tough, and multifunctional PLA materials, increasing their potential application value.

Design of sustainable 3D printable polylactic acid composites with high lignin content.

In this study, we report the development of a sustainable polymer system with 50 wt% lignin content, suitable for additive manufacturing and high value-added utilization of lignin. The plasticized polylactic acid (PLA) was incorporated with lignin to develop the bendable and malleable green composites with excellent 3D printing adaptability. The biocomposites exhibit increases of 765.54 % and 125.27 % in both elongation and toughness, respectively. The plasticizer enhances the dispersion of lignin and the molecular mobility of the PLA chains. The good dispersion of lignin particles within the structure and the reduction of chemical cross-linking promote the local relaxation of the polymer chains. The good local relaxation of the polymer chains and the high flexibility allow to obtain a better integration between the printed layers with good printability. This research demonstrates the promising potential of this composite system for sustainable manufacturing and provides insights into novel material design for high-value applications of lignin.

4D printing light-driven actuator with lignin photothermal conversion module.

Light-responsive shape memory polymers are attractive as they can be activated through remote and spatially-controlled light. In this work, 4D printing of poly(lactic acid) (PLA) composites with a near-infrared light-responsive was achieved by using the simple melt blending method and adding 3 wt% of lignin. Lignin with a conjugated structure was used as the photothermal conversion module. The composites exhibited significant photothermal effects under near-infrared (808 nm) laser irradiation, and the laser irradiation was also effective in initiating and controlling the shape memory. The structure of lignin can be improved by the action of dicumyl peroxide (DCP) to enhance the interfacial adhesion between polyamide elastomer (PAE) and polylactic acid (PLA), reduce the size of dispersed phases, and serve as an effective rheological modifier to exhibit the ideal melt viscosity required for 3D printing of composites. The good mechanical, thermal stability, and rheological properties provide assurance for the 4D printing of composites. This research provides an environmentally friendly and practical method for creating composites that have the potential to serve as ideal actuator components in a range of applications.

Genome physical mapping with large-insert bacterial clones by fingerprint analysis: methodologies, source clone genome coverage, and contig map quality.

Genome physical mapping with large-insert clones by fingerprint analysis is becoming an active area of genomics research. Here, we report two new capillary electrophoresis-based fingerprinting methods for genome physical mapping and the effects of different fingerprinting methods and source clone genome coverage on quality physical map construction revealed by computer simulations and laboratory experiments. It was shown that the manual sequencing gel-based two-enzyme fingerprinting method consistently generated larger and more accurate contigs, followed by the new capillary electrophoresis-based three-enzyme method, the new capillary electrophoresis-based five-enzyme (SNaPshot) method, the agarose gel-based one-enzyme method, and the automatic sequencing gel-based four-enzyme method, in descending order, when 1% or fewer questionable clones were allowed. Analysis of clones equivalent to 5x, 8x, 10x, and 15x genomes using the fingerprinting methods revealed that as the number of clones increased from 5x to 10x, the contig length rapidly increased for all methods. However, when the number of clones was increased from 10x to 15x coverage, the contig length at best increased at a lower rate or even decreased. The results will provide useful knowledge and strategies for effective construction of quality genome physical maps for advanced genomics research.

A BAC- and BIBAC-based physical map of the soybean genome.

Genome-wide physical maps are crucial to many aspects of advanced genome research. We report a genome-wide, bacterial artificial chromosome (BAC) and plant-transformation-competent binary large-insert plasmid clone (hereafter BIBAC)-based physical map of the soybean genome. The map was constructed from 78001 clones from five soybean BAC and BIBAC libraries representing 9.6 haploid genomes and three cultivars, and consisted of 2905 BAC/BIBAC contigs, estimated to span 1408 Mb in physical length. We evaluated the reliability of the map contigs using different contig assembly strategies, independent contig building methods, DNA marker hybridization, and different fingerprinting methods, and the results showed that the contigs were assembled properly. Furthermore, we tested the feasibility of integrating the physical map with the existing soybean composite genetic map using 388 DNA markers. The results further confirmed the nature of the ancient tetraploid origin of soybean and indicated that it is feasible to integrate the physical map with the linkage map even though greater efforts are needed. This map represents the first genome-wide, BAC/BIBAC-based physical map of the soybean genome and would provide a platform for advanced genome research of soybean and other legume species. The inclusion of BIBACs in the map would streamline the utility of the map for positional cloning of genes and QTLs, and functional analysis of soybean genomic sequences.

A BAC-based physical map of the chicken genome.

A genome-wide physical map constructed with bacterial artificial chromosomes (BACs) is an essential component in linking phenotypic traits to the responsible genetic variation in the genomes of plants and animals. We have constructed a physical map of the chicken genome from 57,091 BACs (7.9-fold haploid genome coverage) by restriction fingerprint analysis using high-resolution polyacrylamide gel electrophoresis. The physical map consists of 2331 overlapping BAC contigs and is estimated to span 1510 Mb in physical length. BAC contigs were verified manually and by screening the BACs with 367 DNA markers. A total of 361 of the contigs have been anchored to the existing chicken genetic map. This map represents the first genome-wide, BAC-based physical map of the chicken genome. It provides a powerful platform for many areas of chicken genomics, including targeted marker development, fine mapping of genes and QTL alleles, positional cloning, analysis of avian genome organization and evolution, chicken-mammalian comparative genomics, and large-scale genome sequencing.