In situ wide-angle X-ray scattering together with infrared imaging was performed during three-dimensional material extrusion printing and correlated with the development of the crystalline structure and subsequent thermomechanical properties. Identical samples were printed with nozzle motion either along the short axis or the long axis. The short axis mode had higher thermal retention, which resulted in later onset of crystal structure. The longer time spent at temperatures between the glass transition and the melting point produced samples with higher degree of crystallinity but also significantly increased brittleness. The tracer diffusion coefficient
We detailed a facile detection technique to optically characterize graphene growth and domains directly on growth substrates through a simple thermal annealing process. It was found that thermal annealing transformed the naked Cu to Cu oxides while keeping graphene and graphene-covered Cu intact. This increases the interference color contrast between Cu oxides and Cu, thus making graphene easily visible under an optical microscope. By using this simple method, we studied the factors that affect graphene nucleation and growth and achieved graphene domains with the domain size as large as ~100 μm. The concept of chemically making graphene visible is universal, as demonstrated by the fact that a solution process based on selective H2O2 oxidation has been developed to achieve the similar results in a shorter time. These techniques should be valuable for studies towards elucidating the parameters that control the grains, boundaries, structures and properties of graphene.
Objectives: Traditional pharmacokinetic/pharmacodynamic (PK/PD) and quantitative systems pharmacology (QSP) models often assume uniform drug distribution across various compartments, such as plasma and tissues [Shah and Betts, 2012; Jones et al., 2019], potentially overlooking critical spatial variations that impact drug efficacy and toxicity. This poster aims to:Highlight limitations: Present case studies demonstrating the critical influence of spatial drug distribution on therapeutic outcomes.Introduce a novel approach: Showcase an advanced modeling method that incorporates spatial heterogeneity into QSP frameworks. Demonstrate applications: Provide examples of this novel approach applied in real-world pharmacometric analyses. Methods: We utilized a Computational Fluid Dynamics (CFD) modeling approach [Reid 2021] to simulate the advection-diffusion processes of drug transport within complex tissue morphologies. This method provides a detailed spatial resolution of the pharmacokinetic (PK) profile, which is crucial for understanding how the drug distributes in targeted tissues. Additionally, we integrated these detailed CFD-generated PK profiles with pharmacodynamic (PD) models to evaluate the influence of spatial distribution on drug efficacy and toxicity. Results: We will present the modeling results from the following applications: Gene therapy delivery to CNS tissues: Achieving uniform vector genome transduction in the brain tissue via intraparenchymal delivery of adeno-associated virus (AAV) for gene therapy.Cell adhesion for anti-inflammatory treatments: Predicting leukocyte adhesion on endothelial surfaces, influenced by hydrodynamic flow profiles and the receptor-ligand binding interactions between leukocytes and endothelial cells.Transdermal patch: Analyzing the absorption kinetics and spatial drug distribution within the stratum corneum (SC), the primary barrier in transdermal drug delivery. Conclusions: Our findings highlight the substantial benefits of integrating Computational Fluid Dynamics (CFD) with traditional pharmacokinetic/pharmacodynamic (PK/PD) and quantitative systems pharmacology (QSP) models. This integration enhances the spatial resolution of drug distribution within target tissues, providing critical insights into drug efficacy and toxicity. The use of our CFD-enhanced PK/PD and QSP models (CFD-PK/PD and CFD-QSP) offers a more detailed understanding of drug behaviors in scenarios where the spatial distribution plays an important role, significantly improving therapeutic strategies and outcomes.Citations: [1] Jones, H.M., Z. Zhang, P. Jasper, H. Luo, L.B. Avery, L. E. King, H. Neubert, H. A. Barton, A.M. Betts and R. Webster, CPT Pharmacometrics Syst. Pharmacol. (2019) 8, 738–747.[2] Reid, L., “An Introduction to Biomedical Computational Fluid Dynamics.”, Adv. Exp. Med. Biol. (2021) 1334:205-222.[3] Shah, D.K. and A.M. Betts, J. Pharmacokinet. Pharmacodyn. (2012) 39:67–86.
The use of high-quality graphene as a local probe in combination with photo excitation helps to establish a deep mechanistic understanding of charge generation/quenching processes under lying the graphene/environment interface. By combining a non-destructive bottom-up assembly technique with sensitive graphene-based transistors, a bistable [2]rotaxane-graphene hybrid device, which exhibits a symmetric mirror-image photoswitching effect with logic capabilities, is produced. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
Modeling fluid flow dynamics in metal organic frameworks (MOFs) is a required step toward understanding mechanisms of their activity as novel catalysts, sensors, and filtration materials. We adapted a lattice Boltzmann model, previously used for studying flow dynamics in meso- and microporous media, to the nanoscale dimensions of the MOF pores. Using this model, rapid screening of permeability of a large number of MOF structures, in different crystallographic directions, is possible. The method was illustrated here on the example of an anisotropic MOF, for which we calculated permeability values in different flow directions. This method can be generalized to a large class of MOFs and used to design MOFs with the desired gas flow permeabilities.
Low-voltage, flexibility and low-cost are essential prerequisites for large scale application of organic thin film transistors (OTFTs) in future low-end electronics. Here, we demonstrate a low-voltage flexible OTFT by using a low-temperature, solution-processed gate dielectric. Such a dielectric can be well integrated with an Au coated polyimide film, and exhibits a low leakage current density of less than 10−6 A cm−2 and a high capacitance density of 180 nF cm−2. Pentacene films deposited onto the solution-processed dielectric show a highly ordered "thin film phase". The source–drain (S/D) electrodes are made of in situ modified Cu encapsulated by Au (Au/M-Cu). The obtained flexible OTFT exhibits outstanding electrical characteristics under a gate voltage of only −2 V, which include an on/off ratio of 2 × 104, a mobility (μ) of 1.5 cm2 V−1 s−1, a threshold voltage (VT) of −0.3 V and a subthreshold slope (SS) of 161 mV dec−1. The obtained mobility value is among the highest achieved in flexible pentacene OTFTs. The mechanical flexibility and reliability of the OTFTs are also studied and discussed in detail, and the observed degradation of the device performance under strains is attributed to the damage induced in the electrodes giving rise to increased contact resistance and the phase transition from the thin film phase to bulk phase of the pentacene films.
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