Fluvial Erosion Hazard Mitigation

Fluvial erosion—erosion that occurs along a river—is a major threat to infrastructure, and most commonly to roads. This presentation provides an overview of the Indiana Fluvial Erosion Hazard Mitigation Manual, which was recently developed on behalf of the Indiana Silver Jackets. The manual provides a framework for analyzing, designing, and post-construction management / maintenance for fluvial erosion hazard mitigation projects in Indiana

Noncontact Speckle Contrast Diffuse Correlation Tomography of Blood Flow Distributions in Tissues with Arbitrary Geometries

A noncontact electron multiplying charge-coupled-device (EMCCD)-based speckle contrast diffuse correlation tomography (scDCT) technology has been recently developed in our laboratory, allowing for noninvasive three-dimensional measurement of tissue blood flow distributions. One major remaining constraint in the scDCT is the assumption of a semi-infinite tissue volume with a flat surface, which affects the image reconstruction accuracy for tissues with irregular geometries. An advanced photometric stereo technique (PST) was integrated into the scDCT system to obtain the surface geometry in real time for image reconstruction. Computer simulations demonstrated that a priori knowledge of tissue surface geometry is crucial for precisely reconstructing the anomaly with blood flow contrast. Importantly, the innovative integration design with one single-EMCCD camera for both PST and scDCT data collection obviates the need for offline alignment of sources and detectors on the tissue boundary. The in vivo imaging capability of the updated scDCT is demonstrated by imaging dynamic changes in forearm blood flow distribution during a cuff-occlusion procedure. The feasibility and safety in clinical use are evidenced by intraoperative imaging of mastectomy skin flaps and comparison with fluorescence angiography

A Distinguished Vacuum State for a Quantum Field in a Curved Spacetime: Formalism, Features, and Cosmology

We define a distinguished "ground state" or "vacuum" for a free scalar quantum field in a globally hyperbolic region of an arbitrarily curved spacetime. Our prescription is motivated by the recent construction of a quantum field theory on a background causal set using only knowledge of the retarded Green's function. We generalize that construction to continuum spacetimes and find that it yields a distinguished vacuum or ground state for a non-interacting, massive or massless scalar field. This state is defined for all compact regions and for many noncompact ones. In a static spacetime we find that our vacuum coincides with the usual ground state. We determine it also for a radiation-filled, spatially homogeneous and isotropic cosmos, and show that the super-horizon correlations are approximately the same as those of a thermal state. Finally, we illustrate the inherent non-locality of our prescription with the example of a spacetime which sandwiches a region with curvature in-between flat initial and final regions

Radical Stability vs. Temporal Resolution of EPR-Spectroscopy on Biological Samples

Spin-labeling active compounds is a convenient way to prepare them for EPR spectroscopy with minimal alteration of the target molecule. In this study we present the labeling reaction of dexamethasone (Dx) with either TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) or PCA (3-(carboxy)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy) with high yields. According to NMR data, both labels are attached at the primary hydroxy group of the steroid. In subsequent spin-stability measurements both compounds were applied onto HaCaT cells. When the signal of Dx-TEMPO decreased below the detection limit within 3 h, the signal of Dx-PCA remained stable for the same period of time

Microbial synthesis and transformation of inorganic and organic chlorine compounds

Organic and inorganic chlorine compounds are formed by a broad range of natural geochemical, photochemical and biological processes. In addition, chlorine compounds are produced in large quantities for industrial, agricultural and pharmaceutical purposes, which has led to widespread environmental pollution. Abiotic transformations and microbial metabolism of inorganic and organic chlorine compounds combined with human activities constitute the chlorine cycle on Earth. Naturally occurring organochlorines compounds are synthesized and transformed by diverse groups of (micro)organisms in the presence or absence of oxygen. In turn, anthropogenic chlorine contaminants may be degraded under natural or stimulated conditions. Here, we review phylogeny, biochemistry and ecology of microorganisms mediating chlorination and dechlorination processes. In addition, the co-occurrence and potential interdependency of catabolic and anabolic transformations of natural and synthetic chlorine compounds are discussed for selected microorganisms and particular ecosystems.The authors thank METAEXPLORE, funded by the European Union Seventh Framework Program (Grant No. 222625), BEBASIC-FES funds from the Dutch Ministry of Economic Affairs (Projects F07.001.05 and F08.004.01), Shell Global Solutions International BV, the ERC Advanced grant “Novel Anaerobes” (Project 323009), the SIAM Gravitation grant “Microbes for Health and the Environment” (Project 024.002.002) of the Netherlands Ministry of Education, Culture and Science, and the Netherlands Science Foundation (NWO) for funding.info:eu-repo/semantics/publishedVersio

Drug distribution in nanostructured lipid particles

The targeted design of nanoparticles for efficient drug loading and defined release profiles is even after 25 years of research on lipid-based nanoparticles still no routine procedure. It requires detailed knowledge about the interaction of the drug with the lipid compounds and about its localisation and distribution in the nanoparticle. We present here an investigation on nano-sized lipid particles (NLP) composed of Gelucire and Witepsol as solid lipids, and Capryol as liquid lipid, loaded with Dexamethasone, a glucocorticoid used in topical treatment of inflammatory dermal diseases. The interactions of Dexamethasone, which was spin-labelled by 3-(Carboxy)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (DxPCA), with its microenvironment are monitored by EPR spectroscopy at 94 GHz at low temperatures. The mobility of the spin-labelled drug was probed by X-band EPR at room temperature. In order to relate the magnetic and dynamic parameters deduced from EPR to the local environment of the spin probe in the NLP, investigations of DxPCA in the individual lipid compounds were carried out. The magnetic parameters reflecting the polarity of DxPCA’s environment as well as the parameters describing the mobility of the drug reveal that in the case of colloidal dispersions of the lipids and also the NLP DxPCA is attached to the surface of the nanoparticles. Although the lipophilic drug is almost exclusively associated with the NLP in aqueous solution, dilution experiments show, that it can be easily released from the nanoparticle

Microfluidics for Hydrodynamics Investigations of Sand Dollar Larvae

The life cycle of most marine invertebrates includes a planktonic larval stage before metamorphosis to bottom-dwelling adulthood. During larval stage, ciliary-mediated activity enables feeding (capture unicellular algae) and transport of materials (oxygen) required for the larva's growth, development, and successful metamorphosis. Investigating the underlying hydrodynamics of these behaviors is valuable for addressing fundamental biological questions (e.g., phenotypic plasticity) and advancing engineering applications. In this work, we combined microfluidics and fluorescence microscopy as a miniaturized PIV (mPIV) to study ciliary-medicated hydrodynamics during suspension feeding in sand dollar larvae (Dendraster excentricus). First, we confirmed the approach's feasibility by examining the underlying hydrodynamics (vortex patterns) for low- and high-fed larvae. Next, ciliary hydrodynamics were tracked from 11 days post-fertilization (DPF) to 20 DPF for 21 low-fed larvae. Microfluidics enabled the examination of baseline activities (without external flow) and behaviors in the presence of environmental cues (external flow). A library of qualitative vortex patterns and quantitative hydrodynamics was generated and shared as a stand alone repository. Results from mPIV (velocities) were used to examine the role of ciliary activity in transporting materials (oxygen). Given the laminar flow and the viscosity-dominated environments surrounding the larvae, overcoming the diffusive boundary layer is critical for the organism's survival. Peclet number analysis for oxygen transport suggested that ciliary velocities help overcome the diffusion dominated transport (max Pe numbers between 30-60). Microfluidics serving as mPIV provided a scalable and accessible approach for investigating the ciliary hydrodynamics of marine organisms.Comment: 21 pages and 11 figures (videos not included

Microfluidics Generation of Millimeter-sized Matrigel Droplets

Significant progress has been made to increase access to droplet microfluidics for labs with limited microfluidics expertise or fabrication equipment. In particular, using off-the-shelf systems has been a valuable approach. However, the ability to modify a channel design and, thus, the functional characteristics of the system is of great value. In this work, we describe the development of co-flow microfluidics and their fabrication methods for generating uniform millimeter-sized (0.5 - 2 mm) hydrogel droplets. Two complementary approaches based on desktop CO2 laser cutting were developed to prototype and build durable co-flow droplet microfluidics. After demonstrating the co-flow systems, water-in-oil experiments and dimensionless number analysis were used to examine the operational characteristics of the system. Specifically, the Capillary number analysis indicated that millimeter-sized droplet generators operated in the desirable geometry-controlled regime despite their length scales being larger than traditional microfluidics systems. Next, the tunable generation of Matrigel droplets was demonstrated. By adjusting the relative flow rates, the droplet size could be tuned. Finally, we demonstrated fibroblast encapsulation and cell viability for up to 7 days as a proof-of-concept experiment. The systems presented are simple and effective tools to generate robust hydrogel droplets and increase the accessibility of this technology to teaching labs or research settings with limited resources or access to microfluidics.Comment: 14 pages, 5 figures, 1 tabl

Nanocrystals for Improved Drug Delivery of Dexamethasone in Skin Investigated by EPR Spectroscopy

Nanocrystals represent an improvement over the traditional nanocarriers for dermal application, providing the advantages of 100% drug loading, a large surface area, increased adhesion, and the potential for hair follicle targeting. To investigate their advantage for drug delivery, compared to a base cream formulation, dexamethasone (Dx), a synthetic glucocorticoid frequently used for the treatment of inflammatory skin diseases, was covalently linked with the paramagnetic probe 3-(carboxy)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PCA) to DxPCA. To investigate the penetration efficiency between these two vehicles, electron paramagnetic resonance (EPR) spectroscopy was used, which allows the quantification of a spin-labeled drug in different skin layers and the monitoring of the drug release. The penetration behavior in excised healthy and barrier-disrupted porcine skin was monitored by EPR, and subsequently analyzed using a numerical diffusion model. As a result, diffusion constants and free energy values in the different layers of the skin were identified for both formulations. Dx-nanocrystals showed a significantly increased drug amount that penetrated into viable epidermis and dermis of intact (factor 3) and barrier-disrupted skin (factor 2.1) compared to the base cream formulation. Furthermore, the observed fast delivery of the spin-labeled drug into the skin (80% DxPCA within 30 min) and a successive release from the aggregate unit into the viable tissue makes these nanocrystals very attractive for clinical applications