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Bar codes and quick response codes are the standard methods of visual data storage. These codes rely on changes in visual patterns to encode data into a binary format. Problems with these methods include limited data storage capacity and poor visual appeal in product marketing. This work examined magnetic patterns as an alternative to visual patterns as a potential means to encode data. Using magnetic patterns it is theorized that data storage capacity can be improved, while embedding the code within a tagged object. Magnetic patterns were formed using neodymium magnets, which yielded results that are similar to a bar code. Lines of high magnetic field strength followed by regions of low magnetic field strength at different spacing produced different overall magnetic patterns. Next, magnetic patterns were 3-dimensionally printed using an iron and polylactic acid commercial filament. The effect of infill density and the print line of the magnetic regions were studied by measuring the attractive force between the sample and a neodymium magnet attached to a force gauge for different print configurations. As expected the infill density of 100% had the highest force, which was roughly 330 mN, while the 10% sample had the lowest force being about 120 mN. It was expected that print line should not have an influence on magnetic force, but in this experiment magnetic regions with print lines at 0° were about 10 mN higher than samples printed at 90°. The cause of this was likely due to the printer error. Future work will study print plane, which is another processing variable in 3-dimensional printing. The target goal of matching the data storage capability of QR codes will also be work towards.
Sunlight is the most environmental friendly energy source available on Earth; many efforts devoted to design artificial photoconversion systems are ongoing, nevertheless they are still expensive and poorly efficient. Photoconversion devices made with organic-biological hybrids, or biohybrids, based on the photosynthetic reaction center (RC) have been introduced. In these systems, the photoenzyme is garnished with artificial antennas to enhance the photoactivity of the RC. Here we present a newly synthesized heptamethine cyanine dye that fulfills requisites to act as efficient RC light harvesting antenna.
The photosynthetic Reaction Center from the carotenoidless mutant strain of the purple non sulphur bacterium Rhodobacter (R.) sphaeroides was reconstituted in artificial phospholipid vesicles (liposomes) to mimic the physiological membrane environment. The pH dependence in the interval 5 – 10 of the rate of the charge-recombination reactions from the final electron acceptors QA and QB to the primary electron donor (namely kAD and kBD) have been investigated. The liposomes were constituted of either the zwitterionic phosphatidylcholine (PC) or the negatively charged phosphatidylglycerol (PG), two of the main phospholipids found in the photosynthetic membrane of the bacterium. In both cases, the kAD has no pH dependence similarly to the detergent case. The kBD also has a pH dependence similar to the detergent case, having two distinct regions below pH 7 and above pH 9. Fitting of the titration curve to a function involving two protonation sites results in a marked shift of the pKAs between the different solubilizing environments. These differences are discussed in the frame of possible physiological implications.
This work presents the mesoscale step of a theoretical study of a Polymer-Clay Nanocomposite (PCN) composed by starch, pequi vegetable oil and montmorillonite (MMT), a phyllosilicate. In the present study, amylose oligomers, oleic, palmitic and stearic acids in the proportion found in that vegetable oil and MMT were studied, as a simplified model, in order to simulate in multiscale their structural and behavioral correlations. The calculations were carried out by Dissipative Particle Dynamics (DPD), at 363 K, using Materials StudioTM suite. The DPD model had its interaction parameters calculated from previous MD simulations. It was observed that the organic material concentrated near the MMT surfaces, which correlated with the MD results, implying in the validity of the model. The new knowledge acquired about those molecular systems, works as a starting point to build more complex models and, if the theoretical work converge with the experimental findings, encourages further studies in the design of PCNs with biopolymers.
A computational study based on molecular dynamics simulation technique has been used to predict the mechanical and thermal behavior of carbon nanotube (CNT) reinforced natural rubber (NR) composites. A single-walled 5,5 armchair type CNT has been used for this purpose. In this study, a comparison has been made between pristine and functionalized CNTs. The functionalization groups used in this study were carboxylic (COOH), ester (COOCH3) and hydroxyl (OH). The studies show the improvement in elastic properties of developed composites in the presence of functionalization group. In addition, the effect of volume fraction and 1-25% addition of functionalization group has been studied. The obtained simulation results show the better load-transfer capacity in developed polymer system and improved elastic modulus. Thermal properties of developed composite systems were studied by non-equilibrium molecular dynamics method (NEMD). The addition of functionalized CNTs shows enhanced mechanical and thermal properties.
The effects of La-substitution into SrTiO3 (STO) perovskite oxides on their phase structure, formation enthalpy and electrical conductivity have been investigated. La substitution in STO has been reported to show a significant enhancement in electronic conductivity in a wide-band-gap layered perovskite compound STO. Mixture of Lanthanum and Titanium oxide may lead to various phases including La2/3TiO3, La2Ti2O7 and La2TiO5. In this work, more than 50 structural models have been constructed by considering ionic state substituents, distance between substituents and their concentrations. We investigated the formation enthalpy, elastic properties and band gap by density functional theory (DFT) calculations. We have also investigated the effect of reducing environment on La2/3TiO3. The computed bulk modulus (∼2.4 % deviation) and band gap (∼12% deviation) of STO are in good agreement with the literature. Our results indicate that La substitution into STO could significantly reduce the band gap. Reduction in band gap is maximum when the substituents is present at low concentrations. Internal position of La substituents in STO affects the band gap marginally while energy remains almost same. Formation enthalpy of La2/3TiO3 from LaTiO3 is around 2 eV. La2/3TiO3 acts as band insulator (band gap = 2.8 eV). In reducing environment, the band gap of La2/3TiO3 significantly reduces. Sr substitution in La2/3TiO3 lower the band gap and formation enthalpy. La2Ti2O7 and La2TiO5 have higher band gap and lower bulk modulus than STO. Sr substitution is not feasible in La2Ti2O7 and La2TiO5.
Lung surfactant (LS), a thin layer of phospholipids and proteins inside the alveolus of the lung is the first biological barrier to inhaled nanoparticles (NPs). LS stabilizes and protects the alveolus during its continuous compression and expansion by fine-tuning the surface tension at the air-water interface. Previous modelling studies have reported the biophysical function of LS monolayer and its role, but many open questions regarding the consequences and interactions of airborne nano-sized particles with LS monolayer remain. In spite of gold nanoparticles (AuNPs) having a paramount role in biomedical applications, the understanding of the interactions between bare AuNPs (as pollutants) and LS monolayer components still unresolved. Continuous inhalation of NPs increases the possibility of lung ageing, reducing the normal lung functioning and promoting lung malfunction, and may induce serious lung diseases such as asthma, lung cancer, acute respiratory distress syndrome, and more. Different medical studies have shown that AuNPs can disrupt the routine lung functions of gold miners and promote respiratory diseases. In this work, coarse-grained molecular dynamics simulations are performed to gain an understanding of the interactions between bare AuNPs and LS monolayer components at the nanoscale. Different surface tensions of the monolayer are used to mimic the biological process of breathing (inhalation and exhalation). It is found that the NP affects the structure and packing of the lipids by disordering lipid tails. Overall, the analysed results suggest that bare AuNPs impede the normal biophysical function of the lung, a finding that has beneficial consequences to the potential development of treatments of various respiratory diseases.
Embolic beads for transarterial chemoembolization (TACE) should possess radiopacity and biodegradability at the same time, to be visualized in a body under fluoroscopy and CT scanning to avoid complicating disease. In this study, we fabricated radiopaque and biodegradable beads composed of Lipiodol (LPD) (ethiodized oil) and polycaprolactone (PCL), a biocompatible and biodegradable polymer. LPD/PCL beads were first fabricated with a home-made microfluidic device. By changing the flow-rate ratio in the microfluidic device, the mean diameter of LPD/PCL beads could be well controlled. The radiopacity was evaluated by the fluoroscopic imaging and the CT number measurements. Furthermore, the biodegradability was evaluated by collecting the weight loss data of LPD/PCL immersed in lipase/PBS solution and PBS. The results showed that LPD/PCL beads obtained in this study had sufficient radiopacity and biodegradability, which would be an alternative embolic agent for TACE.