372 research outputs found

    Quantum phases in entropic dynamics

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    In the Entropic Dynamics framework the dynamics is driven by maximizing entropy subject to appropriate constraints. In this work we bring Entropic Dynamics one step closer to full equivalence with quantum theory by identifying constraints that lead to wave functions that remain single-valued even for multi-valued phases by recognizing the intimate relation between quantum phases, gauge symmetry, and charge quantization.Comment: Presented at MaxEnt 2017, the 37th International Workshop on Bayesian Inference and Maximum Entropy Methods in Science and Engineering (July 9-14, 2017, Jarinu, Brazil

    Rotational Dynamics of Organic Cations in CH3NH3PbI3 Perovskite

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    Methylammonium lead iodide (CH3NH3PbI3) based solar cells have shown impressive power conversion efficiencies of above 20%. However, the microscopic mechanism of the high photovoltaic performance is yet to be fully understood. Particularly, the dynamics of CH3NH3+ cations and their impact on relevant processes such as charge recombination and exciton dissociation are still poorly understood. Here, using elastic and quasi-elastic neutron scattering techniques and group theoretical analysis, we studied rotational modes of the CH3NH3+ cation in CH3NH3PbI3. Our results show that, in the cubic (T > 327K) and tetragonal (165K < T < 327K) phases, the CH3NH3+ ions exhibit four-fold rotational symmetry of the C-N axis (C4) along with three-fold rotation around the C-N axis (C3), while in orthorhombic phase (T < 165K) only C3 rotation is present. Around room temperature, the characteristic relaxation times for the C4 rotation is found to be ps while for the C3 rotation ps. The -dependent rotational relaxation times were fitted with Arrhenius equations to obtain activation energies. Our data show a close correlation between the C4 rotational mode and the temperature dependent dielectric permittivity. Our findings on the rotational dynamics of CH3NH3+ and the associated dipole have important implications on understanding the low exciton binding energy and slow charge recombination rate in CH3NH3PbI3 which are directly relevant for the high solar cell performance

    Single coronary artery incidence in 215,140 patients undergoing coronary angiography

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    Background: The aim of our study is to determine the incidence of single coronary artery (SCA). SCA is a rarely seen coronary anomaly in which the right coronary artery and the left main coronary artery arise from single aortic sinus. Although SCA has a benign course in most cases and its clinical significance is unknown, in some autopsy studies it was shown to be related to sudden cardiac death. Materials and methods: SCA patients detected among 215,140 coronary angiographies (CAG) performed between 1998 and 2013 in SANKO Hospital were included in our study. The classification of CAG was made according to the two different classifications defined by Smith and Lipton and colleagues. Results: A total number of 215,140 patients who underwent routine CAG were included in the study, and SCA was detected in 67 (0.031%) patients. There were 6 (9%) type R-I, 23 (34%) type R-II, 10 (15%) type R-III, 16 (24%) type L-I and 12 (18%) type L-II patients according to the angiographic classification. Conclusions: SCA is rarely seen during routine cardiac catheterisation and its incidence is 0.014–0.066% in angiographic series. In our study, the incidence was shown to be similar to the previous studies.

    Investigation of Conjunctival Fibrosis Response Using a 3D Glaucoma Tenon’s Capsule + Conjunctival ModelFibrosis Response Within a 3D Tenon’s + Conjunctival Model

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    Surgical techniques such as trabeculectomy aim to treat glaucoma by making an incision into the scleral tissue, to create an alternative drainage pathway for aqueous to flow into the sub-Tenon’s/subconjunctival space. However, tissue fibrosis and wound healing occurring after the procedures can reduce the success rate. This study aims to investigate the synergistic effects of aqueous humor in combination with shear stress on the fibrosis response occurring in Tenon’s capsule and conjunctival tissue (TCCT) after glaucoma surgery. Two-dimensional (2D) and 3D in vitro TCCT models were constructed by seeding porcine Tenon’s capsule + conjunctival fibroblasts in collagen gel. These were used to investigate key growth factors (singular and natural form) with shear stress, which are believed to influence tissue fibrosis after glaucoma surgery. In addition to cell proliferation assessments, a nondestructive assay to quantify neocollagen synthesis in TCCT models, in response to these factors, has been applied up to 14 days. TCCT fibroblast proliferation increased significantly with doses of TGF-β, TNF-α, and VEGF, in comparison with the control. Furthermore, fibroblasts exposed to 50% aqueous humor had significantly increased proliferation and actin expression. Shear stress–induced mechanotransduction was also found to promote metabolic activity across experimental conditions. Neocollagen labeling cross validated the fibrosis process. Shear stress appeared to enhance the influence of key growth factors and further promoted fibrotic response within the model. These findings offer a useful insight for further study into the wound-healing response triggered by aqueous fluid outflow after glaucoma surgery

    Antibacterial electrospun zein nanofibrous web encapsulating thymol/cyclodextrin-inclusion complex for food packaging

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    Thymol (THY)/γ-Cyclodextrin(γ-CD) inclusion complex (IC) encapsulated electrospun zein nanofibrous webs (zein-THY/γ-CD-IC-NF) were fabricated as a food packaging material. The formation of THY/γ-CD-IC (1:1 and 2:1) was proved by experimental (X-ray diffraction (XRD), thermal gravimetric analysis (TGA), 1H NMR) and computational techniques. THY/γ-CD-IC (2:1) exhibited higher preservation rate and stability than THY/γ-CD-IC (1:1). It is worth mentioning that zein-THY/γ-CD-IC-NF (2:1) preserved much more THY as observed in TGA and stability of THY/γ-CD-IC (2:1) was higher, as shown by a modelling study. Therefore, much more THY was released from zein-THY/γ-CD-IC-NF (2:1) than zein-THY-NF and zein-THY/γ-CD-IC-NF (1:1). Similarly, antibacterial activity of zein-THY/γ-CD-IC-NF (2:1) was higher than zein-THY-NF and zein-THY/γ-CD-IC-NF (1:1). It was demonstrated that zein-THY/γ-CD-IC-NF (2:1) was most effective in inhibiting the growth of bacteria on meat samples. These webs show potential application as an antibacterial food packaging material. © 2017 Elsevier Lt

    Selective and Efficient Removal of Volatile Organic Compounds by Channel-type Gamma-Cyclodextrin Assembly through Inclusion Complexation

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    Cyclodextrins (CD), produced from enzymatic degradation of starch, are a form of biorenewable cyclic oligosaccharide which has an outstanding capability to form inclusion complexes with a variety of molecules including pollutants due to their toroid-shaped molecular structure. In this study, by a simple reprecipitation method, we obtained "channel-type" packing from γ-CD where CD molecules are stacked on top of each other to form long cylindrical channels. The γ-CD "channel-type" crystals have shown very effective removal of organic volatile compounds (VOCs; aniline and toluene) from the surroundings, whereas cage-type γ-CD could not entrap VOCs from the same environment. Encapsulation capability of channel-type γ-CD is at a ∼2:1 and ∼1:1 molar ratio for aniline/CD and toluene/CD, respectively. Thus, channel-type γ-CD crystals have shown higher removal efficiency for aniline compared to toluene. Channel-type γ-CD is also able to remove aniline selectively from surroundings. Additionally, computational modeling studies suggested that single γ-CD cavity can host two molecules of aniline or toluene for the complexation, yet, aniline is more insistent to make a complex with the γ-CD cavity when compared to toluene. We show that channel-type γ-CD can remove VOCs molecules (aniline and toluene) as efficiently as activated carbon. Hence, being a starch-based biorenewable cyclic oligosaccharide in the form of white powder, the use of "channel-type" γ-CD crystals could be a competitive alternative to activated carbon as an adsorbent for the VOC removal/filtering. © 2017 American Chemical Society

    Techno-economic assessment of bioleaching for metallurgical by-products

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    This study focused on the economic feasibility of two potential industrial-scale bioleaching technologies for metal recovery from specific metallurgical by-products, mainly basic oxygen steelmaking dust (BOS-D) and goethite. The investigation compared two bioleaching scaling technology configurations, including an aerated bioreactor and an aerated and stirred bioreactor across different scenarios. Results indicated that bioleaching using Acidithiobacillus ferrooxidans proved financially viable for copper extraction from goethite, particularly when 5% and 10% pulp densities were used in the aerated bioreactor, and when 10% pulp density was used in the aerated and stirred bioreactor. Notably, a net present value (NPV) of 1,275,499kandaninternalrateofreturn(IRR)of651,275,499k and an internal rate of return (IRR) of 65% for Cu recovery from goethite were achieved over 20-years after project started using the aerated and stirred bioreactor plant with a capital expenditure (CAPEX) of 119,816,550 and an operational expenditure (OPEX) of $5,896,580/year. It is expected that plant will start to make profit after one year of operation. Aerated and stirred bioreactor plant appeared more reliable alternative compared to the aerated bioreactor plant as the plant consists of 12 reactors which can allow better management and operation in small volume with multiple reactors. Despite the limitations, this techno-economic assessment emphasized the significance of selective metal recovery and plant design, and underscored the major expenses associated with the process.This research was funded by the European Regional Development Fund as part of the Interreg Northwest Europe project “Regeneration of past metallurgical sites and deposits through innovative circularity for raw materials” (REGENERATIS) (NWE918)

    Unlocking the hidden value of industrial by-products: Optimisation of bioleaching to extract metals from basic oxygen steelmaking dust and goethite

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    In this study, the potential of bioleaching to extract valuable metals from industrial by-products, specifically basic oxygen steelmaking dust (BOS-D) and goethite was investigated. These materials are typically discarded due to their high zinc content and lack of efficient regeneration processes. By using Acidithiobacillus ferrooxidans, successful bioleaching of various metals, including heavy metals, critical metals, and rare earth elements was achieved. The Taguchi orthogonal array design was used to optimise the bioleaching process, considering four variables at three different levels. After 14 days, the highest metal extraction for the BOS-D (11.2 mg Zn/g, 3.2 mg Mn/g, 1.6 mg Al/g, 0.0013 mg Y/g, and 0.0026 mg Ce/g) was achieved at 1% solid concentration, 1% energy source concentration, 1% inoculum concentration, and pH 1.5. For goethite, the optimal conditions were 1% solid concentration, 4% energy source concentration, 10% inoculum concentration, and pH 2 resulting in a extraction of 26.6 mg Zn/g, 2.1 mg/g Mn, 1.8 mg Al/g, 0.01 mg Co/g, 0.0022 mg Y/g. These findings are significant, as they demonstrate the potential to extract valuable metals from previously discarded industrial by-products. The extraction of such metals can have substantial economic and environmental implications, while simultaneously reducing waste in the metallurgical industry. Furthermore, the preservation of initial concentration of iron in both BOS-D and goethite residues represents a significant step towards implementing more sustainable industrial practices.European Union funding: NWE91
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