Rapid Adaptation of Chimonobambusa opienensis Leaves to Crown-Thinning in Giant Panda Ecological Corridor, Niba Mountain.

Leaf traits reflect the ecological strategy in heterogeneous contexts and are widely used to explore the adaption of plant species to environmental change. However, the knowledge of short-term effect of canopy management on understorey plant leaf traits is still limited. Here, we studied the short-term effect of crown-thinning on the leaf morphological traits of bamboo (Chimonobambusa opienensis), an important understorey plant and staple food for the giant panda (Ailuropoda melanoleuca) of Niba Mountain. Our treatments were two crown-thinnings (spruce plantation, CS, and deciduous broad-leaved forest, CB) and two controls (broad-leaved forest canopy, FC, and the bamboo grove of clearcutting, BC). The results showed that: the CS enhanced the annual leaf length, width, area, and thickness, CB decreased almost all annual leaf traits, and perennial leaf traits in CS and CB were the opposite. The log-transformed allometric relationships of length vs. width, biomass vs. area were significantly positive while those of specific leaf area vs. thickness were significantly negative, which varied largely in treatments and age. The leaf traits and allometric relationships suggested that the CS created a more suitable habitat for bamboo growth. This study highlighted that the understorey bamboo leaf traits could adapt the improved light environment induced by crown-thinning rapidly.

Effects of Lyophilization on the Release Profiles of 3D Printed Delivery Systems Fabricated with Carboxymethyl Cellulose Hydrogel.

Recently, increasing numbers of researchers are becoming interested in 3D bioprinting because it provides customizability and structural complexity, which is difficult for traditional subtractive manufacturing to achieve. One of the most critical factors in bioprinting is the material. Depending on the bio-applications, materials should be bio-inert or bio-active, non-toxic, and along with those characteristics, mechanical properties should also meet the applicational or manufacturing requirement. As previously validated for bioprinting, carboxymethyl cellulose (CMC) hydrogel is focused on the printability and release control test in this study. With a differentiated weight percentage of CMC hydrogels were used to 3D print capsules filled with food degradable colorant at designated voids to mimic capsules manufactured for oral delivery. Standard USP (United States Pharmacopeia) dissolution apparatus II (Paddle) evaluations were performed both on lyophilized and non-lyophilized printed capsules. The first-order model was selected due to high linear fitting regression. Upon 24 h dissolution, non-lyophilized capsules showed a different release efficiency when the CMC percentage varied, while lyophilized capsules showed no significant difference. This study signifies the possibility of customizing oral drug delivery by printing capsules with CMC hydrogel. The improved delivery efficiency demonstrated by capsules with post-process lyophilizing proposed potential optimization options for pharmaceutical manufacturing industries.

Development of methylcellulose-based sustained-release dosage by semisolid extrusion additive manufacturing in drug delivery system.

The objective of this study is to fabricate customized dosage forms using extrusion-based 3D printing for the sustained delivery of theophylline. The therapeutic paste was prepared by combining various doses of theophylline (0, 75, 100, and 125 mg) with different concentrations of methylcellulose (MC) A4M (8, 10, and 12%). The paste was then 3D printed into semisolid tablets under optimized printing conditions. The rheological properties of printing pastes were related to the 3D printability. Our results indicated that to be 3D printed using the current platform, the storage modulus (G') of the printing paste should be higher than the loss modulus (G″) during the frequency sweep (0.1-600 rad/s), and the tan δ should fall in the range of 0.25-0.27 at 0.63 rad/s. The printed tablets formulated with 10% MC showed the highest overall quality, considering the aspects of resolution, texture, and shape retention regardless of the dosage. The scanning electron microscopy images indicated that the cross-linked structure of MC A4M formed the microscale porous microstructure, which has the potential to embed the theophylline, thus delayed the release through the barrier effect. The in vitro dissolution test revealed that the 3D printed tablets exhibited a sustained release during the first 12 hr. The findings in this study will support the development of customized, personalized medicine with improved efficacy.

Activation and Assembly of Plasmonic-Magnetic Nanosurfactants for Encapsulation and Triggered Release.

Multifunctional surfactants hold great potentials in catalysis, separation, and biomedicine. Highly active plasmonic-magnetic nanosurfactants are developed through a novel acid activation treatment of Au-Fe3O4 dumbbell nanocrystals. The activation step significantly boosts nanosurfactant surface energy and enables the strong adsorption at interfaces, which reduces the interfacial energy one order of magnitude. Mediated through the adsorption at the emulsion interfaces, the nanosurfactants are further constructed into free-standing hierarchical structures, including capsules, inverse capsules, and two-dimensional sheets. The nanosurfactant orientation and assembly structures follow the same packing parameter principles of surfactant molecules. Furthermore, nanosurfactants demonstrate the capability to disperse and encapsulate homogeneous nanoparticles and small molecules without adding any molecular surfactants. The assembled structures are responsive to external magnetic field, and triggered release is achieved using an infrared laser by taking advantage of the enhanced surface plasmon resonance of nanosurfactant assemblies. Solvent and pH changes are also utilized to achieve the cargo release.

3D printing of extended-release tablets of theophylline using hydroxypropyl methylcellulose (HPMC) hydrogels.

An extrusion based 3D printer was used to prepare the semi-solid tablets with different drug loading dosages (75, 100, 125 mg) under ambient temperature. The active pharmaceutical ingredient, theophylline, was uploaded within the hydrogels prepared of hydroxypropyl methylcellulose (HPMC) K4M or E4M. The HPMC concentrations were adjusted to different levels (10 and 12% w/w) to fulfill the requirements for 3D printing. Rheological and textural properties, as well as release profiles, were significantly affected by the type and concentration of excipient regardless of theophylline doses used. The printing material should exhibit shear-thinning behavior, keeping yield stress less than 4000 Pa and a loss factor (tanδ = G''/G') between 0.2 and 0.7, especially for 3D printing purposes using the current platform. The SEM images demonstrated that the hydrogel matrix exhibited a porous structure, which had the potential to encapsulate the theophylline clusters within its microstructure. The in vitro dissolution test showed that the release of all tablets was extended over 12 h, and the calculation of drug release kinetic models revealed that the 3D printed HPMC matrices release the theophylline by diffusion and erosion mechanisms. The excipient HPMC K4M 12% w/w hydrogel was optimal to load the theophylline with flexible dosage combinations due to the great extrudability and shape retention ability. The exploration of rheological properties was investigated in this study, and the results revealed that it is a feasible method to predict the SSE 3D printability and quality of hydrogel-API blend materials for the drug delivery system.