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3D printing is a process of hierarchically fabricating three-dimensional microstructures by successively adding materials in a bottom-up manner. The technology has been rapidly advancing, especially in the manufacturing of high-strength, lightweight industrial composite materials. Thus far, many studies have focused on the spontaneous alignment of short reinforcing fibers that are subject to adjustment during the 3D-printing process, along with an inevitable void formation arising due to an intrinsic nature of the additive process. However, systematic examination of the 3D-printed anisotropic microstructures, related with a markedly high degree of fiber alignment and formation of voids in the matrix, has not been sufficiently conducted to analyze its effect on the anisotropic mechanical behaviors of fiber-reinforced composites. Here, we sought to examine in detail the internal morphology of fibers and voids in 3D-printed composites by 3D X-ray microscopy to explore their anisotropic architecture. The position, length, and alignment of fibers and voids were identified, visualized, and quantitatively characterized with a help of computational tomography (CT). Furthermore, the anisotropy approximation of the 3D-printed composites, precisely predicted through CT-assisted simulation, was derived based on the quantitative data obtained from the 3D reconstruction image. These measurements were effective in exploring the process-induced alignment nature of fibers and voids in the local region layers on the microscopic scale, and the corresponding microstructure resulted in a change in the elastic modulus of the composites with the printing direction. The comparative results showed that the experimental results were well supported by the simulation-based estimations, but did not exactly match the rule-of-mixture of the composites in terms of interfacial nature due to the distinctive microstructure with the fiber-to-matrix interface as well as the filament-to-filament interface.

Oxidative stress is induced by accumulation of hydrogen peroxide (H2O2), and therefore, H2O2 could serve as a potential biomarker of various oxidative stress-associated inflammatory diseases. Vanillin is one of the major components of natural vanilla and has potent antioxidant and anti-inflammatory activities. In this work, we developed a novel inflammation-responsive antioxidant polymeric prodrug of vanillin, termed poly(vanillin oxalate) (PVO). In design, PVO incorporates H2O2-reacting peroxalate ester bonds and bioactive vanillin via acid-responsive acetal linkages in its backbone. Therefore, in cells undergoing damages by oxidative stress, PVO readily degrades into three nontoxic components, one of which is antioxidant and anti-inflammatory vanillin. PVO nanoparticles exhibit potent antioxidant activities by scavenging H2O2 and inhibiting the generation of ROS (reactive oxygen species) and also reduce the expression of pro-inflammatory cytokines in activated macrophages in vitro and in vivo. We, therefore, anticipate that PVO nanoparticles have great potential as novel antioxidant therapeutics and drug delivery systems for ROS-associated inflammatory diseases.

Overproduction of hydrogen peroxide (H2O2) causes oxidative stress and is the main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury. Suppression of oxidative stress is therefore critical in the treatment of I/R injury. Here, we report H2O2-activatable antioxidant prodrug (BRAP) that is capable of specifically targeting the site of oxidative stress and exerting anti-inflammatory and anti-apoptotic activities. BRAP with a self-immolative boronic ester protecting group was designed to scavenge H2O2 and release HBA (p-hydroxybenzyl alcohol) with antioxidant and anti-inflammatory activities. BRAP exerted potent antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)- and H2O2-stimulated cells by suppressing the generation of ROS and pro-inflammatory cytokines. In mouse models of hepatic I/R and cardiac I/R, BRAP exerted potent antioxidant, anti-inflammatory and anti-apoptotic activities due to the synergistic effects of H2O2-scavenging boronic esters and therapeutic HBA. In addition, administration of high doses of BRAP daily for 7 days showed no renal or hepatic function abnormalities. Therefore BRAP has tremendous therapeutic potential as H2O2-activatable antioxidant prodrug for the treatment of I/R injuries.

Doxorubicin (DOX) is a commonly used anti-neoplastic agent but its clinical use is limited due to serious hepatic and cardiac side effects. DOX-induced toxicity is mainly associated with overproduction of reactive species oxygen (ROS) such as hydrogen peroxide (H2O2). We have recently developed H2O2-responsive anti-oxidant polymer, polyoxalate containing vanillyl alcohol (PVAX), which is designed to rapidly scavenge H2O2 and release vanillyl alcohol with anti-oxidant, anti-inflammatory and anti-apoptotic properties. In this study, we report that PVAX nanoparticles are novel therapeutic agents for treating DOX-induced cardiac and hepatic toxicity. Intraperitoneal injection of PVAX nanoparticles (4 mg/kg/day) resulted in significant inhibition in apoptosis in liver and heart of DOX-treated mice by suppressing the activation of poly (ADP ribose) polymerase 1 (PARP-1) and caspase-3. PVAX treatment also prevented DOX-induced cardiac dysfunction. Furthermore, survival rate (vehicle = 35% vs. PVAX = 75%; p < 0.05) was significantly improved in a PVAX nanoparticles-treated group compared with vehicle treated groups. Taken together, we anticipate that PVAX nanoparticles could be a highly specific and potent treatment modality in DOX-induced cardiac and hepatic toxicity.

The main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury is the overproduction of reactive oxygen species (ROS). Hydrogen peroxide (H2O2), the most abundant form of ROS produced during I/R, causes inflammation, apoptosis and subsequent tissue damages. Here, we report H2O2-responsive antioxidant nanoparticles formulated from copolyoxalate containing vanillyl alcohol (VA) (PVAX) as a novel I/R-targeted nanotherapeutic agent. PVAX was designed to incorporate VA and H2O2-responsive peroxalate ester linkages covalently in its backbone. PVAX nanoparticles therefore degrade and release VA, which is able to reduce the generation of ROS and exert anti-inflammatory and anti-apoptotic activity. In hind-limb I/R and liver I/R models in mice, PVAX nanoparticles specifically reacted with overproduced H2O2 and exerted highly potent anti-inflammatory and anti-apoptotic activities that reduced cellular damages. Therefore, PVAX nanoparticles have tremendous potential as nanotherapeutic agents for I/R injury and H2O2-associated diseases.

A novel scan matching method based on a spectral technique is proposed to estimate the robot pose by matching 2D range scans without an initial alignment. The proposed method finds consistent correspondence between two range scans, by considering how well their associated pairwise geometric relationships are satisfied.

Carbon Nanotubes (CNTs) of sufficiently large diameter and a few layers self-collapse into flat ribbons at atmospheric pressure, forming bundles of stacked CNTs that maximize packing and thus CNT interaction. Their improved stress transfer by shear makes collapsed CNTs ideal building blocks in macroscopic fibers of CNTs with high-performance longitudinal properties, particularly high tensile properties as reinforcing fibres. This work introduces cross-sectional transmission electron microscopy of FIB-milled samples as a way to univocally identify collapsed CNTs and to determine the full population of different CNTs in macroscopic fibers produced by spinning from floating catalyst chemical vapour deposition. We show that close proximity in bundles is a major driver for collapse and that CNT stoutness (number of layers/diameter), which dominates the collapse onset, is controlled by the growth promotor. Despite differences in decomposition route, different C precursors lead to similar distributions of the ratio layers/diameter. The synthesis conditions in this study give a maximum fraction of collapsed CNTs of 70$\%$ when using selenium as promotor, corresponding to an average of $0.25 layer/nm$.