Tuning the Thermal Conductivity of the Amorphous PAA Polymer via Vapor-Phase Infiltration.

The thermal properties of the polymer, together with mechanical stability, have been one of the key engineering factors to be considered for various applications. Here, we engineered the thermal conductivity of the amorphous poly(acrylic acid) (PAA) polymer by vapor-phase infiltration (VPI), which has usually occurred during the atomic layer deposition process. We observed that the VPI causes metal infiltration (e.g., Al and Zn) into the amorphous PAA polymer, which noticeably increases the thermal conductivity of the PAA polymer. From spectroscopy analysis and density functional theory simulations, we found that the carboxyl groups (-COOH) in PAA are notably modified and the bonding states of carbon and oxygen are significantly altered by the infiltrated metal. The newly formed Al-mediated bonds likely provide continuous phonon propagation pathways, thereby enhancing the thermal conductance. We believe that VPI could be a simple and useful way to engineer the thermal properties of various polymeric materials.

Enhanced Mechanical Stability and Biodegradability of Ti-Infiltrated Polylactide.

Biodegradable polymers have been often used in place of conventional nondegradable polymers for industrial and medical applications. In particular, polylactide (PLA) has been regarded as a popular ecofriendly plastic and has many advantages like good biocompatibility and processability. Yet, it still has some drawbacks in mechanical properties. Here, we prepared Ti-infiltrated PLA by mimicking the gelatinous jaw of a seaworm whose mechanical properties are toggled up and down by the tiny amount of metal ions, expecting to prepare a new type of alternative. Ti induced significant chemical and microstructural changes in the PLA, which led to a notable improvement in the mechanical properties as compared to the neat PLA. The Ti-infiltrated PLA exhibited high resistance to rapid degradation. More importantly, the toxicity assessment demonstrated that the resulting PLA is still biocompatible and nontoxic. Consequently, we proved that the Ti-infiltrated PLA has high mechanical properties comparable to conventional nondegradable polymers and good biocompatibility as well as delayed biodegradability. We anticipate the current Ti-infiltrated PLA to be an ecofriendly replacement of some conventional plastics, which helps preserve a green environment.

Synergistic protective effects of a statin and an angiotensin receptor blocker for initiation and progression of atherosclerosis.

AIM: Although the atheroprotective effects of statins and angiotensin II receptor blockers (ARBs) are well-established, little is known about their additive effects, especially during the early period of atherosclerosis. The aim of this study was to investigate whether combination of a statin and an ARB exerts synergistic anti-atherosclerotic effects, and to elucidate the mechanisms of combined effects. METHODS: Atherosclerotic plaques were developed in arteries of 23 rabbits using a high-cholesterol diet (HCD) and intra-arterial balloon inflation. Rabbits received one of five different treatment strategies for 4 weeks: positive control [n = 5, HCD]; negative control [n = 3, regular chow diet]; statin [n = 5, HCD and rosuvastatin 10 mg]; ARB [n = 5, HCD and olmesartan 20 mg]; and combination [n = 5, HCD and statin+ARB]. RESULTS: Histological analysis demonstrated that development of atherosclerotic plaques was inhibited more in combination group than in statin group (P = 0.001). Although macrophage infiltration identified by RAM11 staining was not significantly different between combination and individual treatment groups (31.76±4.84% [combination] vs. 38.11±6.53% [statin; P = 0.35] or 35.14±2.87% [ARB; P = 0.62]), the relative proportion of pro-inflammatory M1-macrophages was significantly lower in combination group than in ARB group (3.20±0.47% vs. 5.20±0.78%, P = 0.02). Furthermore, M2-macrophage polarization was higher in combination group than in statin group (17.70±3.04% vs. 7.86±0.68%, P = 0.001). CONCLUSION: Combination treatment with a statin and an ARB produced synergistic protective effects for atherosclerosis initiation and progression, which may be attributed to modulation of macrophage characteristics in the early period of atherosclerosis.

Comparison of clinical outcomes of two different types of paclitaxel-coated balloons for treatment of patients with coronary in-stent restenosis.

Drug-coated balloon (DCB) angioplasty has been shown to be a promising option for the treatment of coronary in-stent restenosis (ISR). We compared the clinical outcomes of patients with ISR who were treated with two commonly used paclitaxel-containing DCBs, the Pantera Lux (PL) and SeQuent Please (SP). A total of 491 patients with 507 ISR lesions [PL-DCB in 127 (26%) patients and SP-DCB in 364 (74%) patients] underwent DCB angioplasty for ISR lesions. The major adverse cardiac events (MACEs), including cardiac death, target lesion-related myocardial infarction, and target lesion revascularization, were assessed. There were no significant differences in each occurrence of MACE and cardiac death: 16 MACEs (61 per 1000 person-years) in the PL-DCB group and 55 (60 per 1000 person-years) MACEs in the SP-DCB group, log-rank p = 0.895, and three cardiac deaths (11 per 1000 person-years) in the PL-DCB group and ten cardiac deaths (11 per 1000 person-years) in the SP-DCB group, log-rank p = 0.849. Diabetes mellitus under insulin treatment [hazard ratio (HR) 2.71; 95% confidence interval (CI) 1.31-5.60; p = 0.007], chronic kidney disease (HR 1.99; 95% CI 1.01-3.92; p = 0.045), early-onset ISR (HR 1.99; 95% CI 1.18-3.36; p = 0.010), and recurrent ISR (HR 1.89; 95% CI 1.08-3.32; p = 0.026) were associated with the occurrence of MACE after DCB angioplasty. There was no significant difference of MACE between PL-DCB and SP-DCB treatment in patients with ISR. Patients with insulin-treated diabetes, chronic kidney disease, early-onset ISR, and recurrent ISR were at a higher risk of MACE after DCB angioplasty.