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Self-assembly methods are used for the production of photonic and nanoporous materials derived from block copolymers. In this context, bottle-brush copolymers have demonstrated a number of advantages over the respective linear copolymers, such as faster self-assembly kinetics and a richer morphology behavior. However, the effect of intrinsic molecular stiffness on the morphology of bottle-brush copolymers has been previously overlooked. Here, we investigate the role of the intrinsic backbone chain stiffness on the morphology behavior of bottle-brush diblock copolymers by using molecular dynamics simulations of a bead-spring coarse-grained model. We focus on bottle-brush macromolecules having blocks of the same volume fraction and asymmetric-in-length side chains. We find that an increase of the backbone stiffness triggers an order–order transition from hexagonal packed cylinders to lamellar morphologies with asymmetric domain spacings, which is of particular interest for the manufacturing of nanopatterning and semiconductor applications. The change in the morphology is due to the effective many-body attractions between the blocks resulting in a parallel stacking that disrupts the symmetry of the cylindrical morphology. We anticipate that our work will underline the significance of intrinsic molecular stiffness in the self-assembly of polymer systems, which has been previously neglected. [ABSTRACT FROM AUTHOR]

Recent developments in “superspreading” are highlighted showing this phenomenon to be due to the combined effect of diffusion processes, Marangoni stresses, surfactant, solvent and substrate chemistry, and ambient conditions. The ultimate resolution of the driving mechanisms will involve the application of molecular dynamics simulations together with continuum-scale modeling and multi-scale experimentation. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to explore the relationship of neointimal thickness (NT) to shear stress (SS) after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) compared with bare-metal stents (BMS). We then tested the hypothesis that drug elution attenuates the SS effect. Background: Neointimal thickness after BMS implantation has been associated with SS; pertinent data for drug-eluting stents (DES) are limited. Methods: Three-dimensional coronary artery and stent reconstruction was performed in 30 patients at 6-month follow-up after SES (n = 10), PES (n = 10), or BMS (n = 10) implantation. Baseline SS at the stent surface was calculated using computational fluid dynamics and NT at follow-up was computed in 3-dimensional space. Results: Neointimal thickness was lower in DES versus BMS (0.03 ± 0.07 mm vs. 0.16 ± 0.08 mm, p < 0.001) and maximum NT was reduced in SES versus PES (0.33 ± 0.13 mm vs. 0.46 ± 0.13 mm, p = 0.025). In the total population, both SS (slope: −0.05 mm/Pa, p < 0.001) and DES (coefficient for DES vs. BMS: −0.17 mm, p = 0.003) were independent predictors of NT. Subgroup analysis demonstrated a significant negative relationship of NT to SS in PES (slope: −0.05 mm/Pa, p = 0.016) and BMS (slope: −0.05 mm/Pa, p = 0.001). Sirolimus elution significantly attenuated the effect of SS on NT (interaction coefficient for SES vs. BMS: 0.04 mm/Pa, p = 0.023), whereas the SS effect remained unchanged in PES (interaction coefficient for PES vs. BMS: 0.01 mm/Pa, p = 0.71). Conclusions: Neointimal thickness is significantly correlated (inversely) to SS in PES as in BMS. Sirolimus elution abrogates the SS effect on the neointimal response following stent implantation, whereas the SS effect is unchanged in PES. [ABSTRACT FROM AUTHOR]

Abstract: Background: The association of shear stress (SS) with in-stent restenosis after bare metal stenting is not clear. We investigated the significance of SS on predicting areas with neointima thickness (NT) in humans and the effect of vascular brachytherapy (VBT) following coronary artery stenting on the relationship of SS with NT. Methods: By using coronary angiography and intravascular ultrasound, we performed three-dimensional (3D) artery and stent reconstruction in 14 patients at 8-month follow-up after bare metal stenting with (stent&VBT group; 7 patients) or without (stent group; 7 patients) adjunctive beta-VBT. In-stent SS was calculated by applying computational fluid dynamics to the stent reconstruction and NT was determined in 3D space. Results: NT was significantly increased in the stent group (0.2±0.16 mm vs. 0.07±0.18 mm, p <0.001). The estimated intercepts and slopes regarding the relationship of NT with SS were 0.28 mm [95% confidence interval (CI): 0.20 to 0.36 mm, p <0.001] and −0.057 mm/Pa (95% CI: −0.062 to −0.052 mm/Pa, p <0.001) respectively for the stent group, and 0.15 mm (95% CI: −0.02 to 0.31 mm, p =0.082) and −0.017 mm/Pa (95% CI: −0.023 to −0.010 mm/Pa, p <0.001) respectively for the stent&VBT group. After pooling all data together, a significant effect of VBT on the relationship between NT and SS was found [estimate of interaction term (group×SS) for stent&VBT vs. stent group: 0.04 mm/Pa; 95% CI: 0.032 to 0.049 mm/Pa, p <0.001]. Conclusions: In-stent restenosis is inversely related to SS after coronary artery stenting and VBT diminishes the inverse relationship between NT and SS. [Copyright &y& Elsevier]

Abstract: We report for the first time a real three-dimensional reconstruction of the left main coronary artery, left main bifurcation, left anterior descending coronary artery and left circumflex coronary artery using biplane angiography and intravascular ultrasound imaging in a patient with a proximal stenosis in the left anterior descending coronary artery. By using computational fluid dynamics in the three-dimensional luminal model we computed endothelial shear stress, while plaque thickness was calculated as the difference between the three-dimensional lumen and outer vessel wall; plaque thickness was found to be inversely related to endothelial shear stress in the left main coronary artery and bifurcation. The application of our methodology for real three-dimensional reconstruction of the left main coronary artery and bifurcation is useful for investigating the relationship of hemodynamic parameters with plaque thickness in this critical coronary region. [Copyright &y& Elsevier]

The fresh-cut potato is popular in many foods, but its shelf-time is difficult to predict. Through orthogonal test, the fresh-cut potato was dipped in chlorine dioxide solution (100 mg/L), citric acid solution (1.5%) and potassium sorbate solution (0.1%) in order, and then packaged with polyvinylidene chloride plastic film for the best preservation effect. Then, the processed potatoes were stored in 0 °C, 4 °C, 7 °C and 10 °C. The quality-change relationship between samples over time and temperature are mainly studied by weight loss, PPO activity and total number of colonies. The results show that the weight loss, the PPO activity and the total number of colonies increased with the increase of the time and the temperature, and the temperature of 0 °C is optimum for the storage of fresh-cut potato. The kinetic models of the weight loss, the PPO activity and the total number of colonies are established based on experimental data. By comparing the predicted values with the experimental values, it is shown that the shelf-life prediction model of PPO activity can offer a more accurate prediction of the shelf life of fresh-cut potato at different temperatures. We anticipate that our results might be used to forecast and evaluate the quality of vegetables in the process of logistics. • Three different shelf-life prediction models of fresh-cut potato are provided. • The PPO activity prediction model can predict the shelf life of fresh-cut potato at different temperatures. • Effect of temperature is a key factor in the storage and transportation processes of fresh-cut potato. [ABSTRACT FROM AUTHOR]

To reach the goal of becoming carbon neutral, there is a necessity to optimize the cold logistics due to its huge energy consumption and waste. Here, the life cycle assessment method was used to calculate the carbon emissions at each step of the fruit and vegetable cold chain. Based on the energy balance equation, the refrigerated transportation methods and carbon emissions under different transportation times was studied. The results show that the carbon emission of 1 kg of fruits and vegetables in the cold logistics is 0.098 kg: In this carbon emission, the transportation step accounts for 82%, while the emission of the pre-cooling step, storage (sales) step and consumption (abandonment) step account for 7%, 6% and 5%, respectively. If the transportation time is within 5 h, the pre-cooled fruits and vegetables are best to be transported by insulated transportation. If the transportation time is between 5 and 60 h, the preferable transportation method is the cold storage transportation. Moreover, 70 kg of cold storage agent is needed per cubic meter when the latent heat of the cold storage agent is 270 kJ/kg. Comparing the cold storage transportation with the mechanical refrigerated transportation, the transportation time is less than 87 h (1.5tons) and 98 h (10tons), that is the cold storage transportation has lower carbon emission. We also found that the driving carbon emission of a 1.5tons small refrigerated truck is three times that of a 10tons heavy refrigerated truck. In order to reduce the carbon emission in the transportation step, a smaller shape factor H, a cold storage agent with a large phase change latent heat and a thicker insulation layer have been suggested. ● The CO 2 emission of three different transportation types was calculated during the cold chain. ● The time used to decide on the transportation type was provided during the cold chain based on the CO 2 emission ● The method to reduce the CO 2 emission of the transportation step has been suggested. [ABSTRACT FROM AUTHOR]