Continuous and Adaptive Cartographic Generalization of River Networks

The focus of our research is on a new automated smoothing method and its applications. Traditionally, the application of a smoothing method to a collection of polylines produces a new smoothed dataset. Although the new dataset was derived from the original dataset, it is stored independently. Since many smoothing methods are slow to execute, this is a valid trade-off. However, this greatly increases the data storage requirements for each new smoothing. A consequence of this approach is that interactive map systems can only offer maps at a discrete set of scales. It is desirable to have a fast enough method that would support the reuse of a single base dataset for on-the-fly smoothing for the production of maps at any scale.We were able to create a framework for the automated smoothing of river networks based on the following major contributions:– A wavelet--based method for polyline smoothing and endpoint preservation– Inverse Mirror Periodic (IMP) representation of functions and signals, and dimensional wavelets– Smoothing of features that does not change abruptly between scales– Features are pruned in a continuous manner with respect to scale– River network connectedness is maintained for all scales– Reuse of a base geographic dataset for all scales– Design and implementation of an interactive map viewer for linear hydrographic features that renders in subsecond timeWe have created an interactive map that can smoothly zoom to any region. Numerical experiments show that our wavelet-based method produces cartographically appropriate smoothing for tributaries. The system is implemented to view hydrographic data, such as the USGS National Hydrography Dataset (NHD). The map demonstrates that a wavelet--based approach is well suited for basic generalization operations. It provides smoothing and pruning that is continuously dependent on map scale

Biofouling of Reverse Osmosis Membranes: Positively Contributing Factors of <i>Sphingomonas</i>

In the present study, we investigate the possible contribution of <i>Sphingomonas</i> spp. glycosphingolipids (GSL) and its extracellular polymeric substances (EPS) to the initial colonization and development of biofilm bodies on reverse osmosis (RO) membranes. A combination of an RO cross-flow membrane lab unit, a quartz crystal microbalance with dissipation (QCM-D), and a rear stagnation point flow (RSPF) system with either model bacteria (<i>Sphingomonas wittichii</i>, <i>Escherichia coli</i>, and <i>Pseudomonas aeruginosa</i>) or vesicles made of the bacterial GSL or LPS was used. Results showed noticeable differences in the adhesion LPS versus GSL vesicles in the QCM-D, with the latter exhibiting 50% higher adhesion to polyamide coated crystals (mimicking an RO membrane surface). A similar trend was observed for EPS extracted from <i>S. wittichii</i>, when compared to the adhesion tendency of EPS extracted from <i>P. aeruginosa</i>. By applying the whole-cell approach in the RO lab unit, the cumulative impact of <i>S. wittichii</i> cells composing GSL and probably their EPS reduced the permeate flux during bacterial accumulation on the membrane surface. Experiments were conducted with the same amount of <i>Sphingomonas</i> spp. or <i>Escherichia coli</i> cells resulting in a two times greater flux decline in the presence of <i>S. wittichii</i>. The distinct effects of <i>Sphingomonas</i> spp. on RO membrane biofouling are likely a combination of GSL presence (known for enhancing adhesion when compared to non-GSL containing bacteria) and the EPS contributing to the overall strength of the biofilm matrix

Bacterial Attachment and Viscoelasticity: Physicochemical and Motility Effects Analyzed Using Quartz Crystal Microbalance with Dissipation (QCM-D)

This investigation is focused on the combined effect of bacterial physicochemical characteristics and motility on cell adhesion and deposition using a flow-through quartz crystal microbalance with dissipation (QCM-D). Three model flagellated strains with different degrees of motility were selected, including a highly motile <i>Escherichia coli</i> K12 MG1655, an environmental strain <i>Sphingomonas wittichii</i> RW1, and a nonmotile (with paralyzed flagella) <i>Escherichia coli</i> K12 MG1655 Δ<i>motA</i> that is incapable of encoding the motor torque generator for flagellar movement. Of the three strains, <i>S. wittichii</i> RW1 is highly hydrophobic, while <i>E. coli</i> strains are equally hydrophilic. Consideration of the hydrophobicity provides an alternative explanation for the bacterial adhesion behavior. QCM-D results show that motility is a critical factor in determining bacterial adhesion, as long as the aquatic chemical conditions are conducive for motility and the substratum and bacterial surface are similarly hydrophobic or hydrophilic. Once their properties are not similar, the contribution of hydrophobic interactions becomes more pronounced. QCM-D results suggest that during adhesion of the hydrophobic bacterium, <i>S. wittichii</i> RW1, the initial step of adhesion and maturation of bacteria–substratum interaction on hydrophilic surface includes a dynamic change of the viscoelastic properties of the bond bacterium-surface becoming more viscously oriented

Glycosphingolipids Enhance Bacterial Attachment and Fouling of Nanofiltration Membranes

Biofouling is a ubiquitous problem in many places in society and technology, especially in reverse osmosis or nanofiltration (NF) processes. Initial stages in the development of the biofilm include attachment of bacteria to the surface, where bacterial outer membrane components such as biopolymers, lipids, and proteins play important roles. Here we show that the glycosphingolipid (GSL) unique to <i>Sphingomonas</i> species is a key player in the initial attachment of bacteria to NF membranes whereas lipopolysaccharide (LPS), the major glycolipid in many Gram-negative species, is less significant. GSL and LPS were deposited on an NF membrane with subsequent bacterial culture injection in a three-dimensionally printed microfluidic flow cell. Flux, rejection, and pressure changes showed that GSL caused permanent membrane fouling. This study underlines the significance of <i>Sphingomonas</i> for the initial attachment of bacteria to membranes. A deeper understanding and identification of key components in the biofouling process may help define strategies for biofilm prevention

Matrix Metalloproteinases Expression Is Associated with SARS-CoV-2-Induced Lung Pathology and Extracellular-Matrix Remodeling in K18-hACE2 Mice

The COVID-19 pandemic caused by the SARS-CoV-2 infection induced lung inflammation characterized by cytokine storm and fulminant immune response of both resident and migrated immune cells, accelerating alveolar damage. In this work we identified members of the matrix metalloprotease (MMPs) family associated with lung extra-cellular matrix (ECM) destruction using K18-hACE2-transgenic mice (K18-hACE2) infected intranasally with SARS-CoV-2. Five days post infection, the lungs exhibited overall alveolar damage of epithelial cells and massive leukocytes infiltration. A substantial pulmonary increase in MMP8, MMP9, and MMP14 in the lungs post SARS-CoV-2 infection was associated with degradation of ECM components including collagen, laminin, and proteoglycans. The process of tissue damage and ECM degradation during SARS-CoV-2 lung infection is suggested to be associated with activity of members of the MMPs family, which in turn may be used as a therapeutic intervention