Suspended Media Research Articles

Turbidity Removal of Landscape Water by Filtration Bed with Suspended Media

High turbidity seriously affects the landscape effect of urban landscape water. In order to explore the turbidity removal effect of filtration bed with suspended media materials on landscape water, a filtration test was carried out with Xinhe river in Fengxi new city. The results showed that the filter bed had an effective and reliable removal performance on turbidity and suspended solids in landscape water. The turbidity removal rates were 44.50%-77.24%, and the suspended solid removal rates were 50.37%-78.85%. The use of expended polystyrene filter media material and upward flow direction got higher remove effect of the turbidity. Suspended solid particles with size less than 100 μm is the limiting factor affecting the treatment effect of the filter bed, and the expanded polystyrene filter material had a better removal effect on the particulate matter in this range. On the premise of ensuring the treatment effect, the filter bed with suspended media has the advantages of low backwash energy consumption and long filtration period, therefore, it is suitable to be used as the pre-treatment unit of landscape water treatment project.

Cryopreservation of Viable Human Tissues: Renewable Resource for Viable Tissue, Cell Lines, and Organoid Development.

The availability of viable human tissues is critical to support translational research focused on personalized care. Most studies have relied on fresh frozen or formalin-fixed paraffin-embedded tissues for histopathology, genomics, and proteomics. Yet, basic, translational, and clinical research downstream assays such as tumor progression/invasion, patient-derived xenograft, organoids, immunoprofiling, and vaccine development still require viable tissue, which are time-sensitive and rare commodities. We describe the generation of two-dimensional (2D) and three-dimensional (3D) cultures to validate a viable freeze cryopreservation technique as a standard method of highest quality specimen preservation. After surgical resection, specimens were minced, placed in CryoStor™ media, and frozen using a slow freezing method (-1°C/min in -80°C) for 24 hours and then stored in liquid nitrogen. After 15-18 months, the tissues were thawed, dissociated into single-cell suspensions, and evaluated for cell viability. To generate primary 2D cultures, cells were plated onto Collagen-/Matrigel-coated plates. To develop 3D cultures (organoids), the cells were plated in reduced serum RPMI media on nonadherent plates or in Matrigel matrix. The epithelial nature of the cells was confirmed by using immunohistochemistry for cytokeratins. DNA and RNA isolation was performed using QIAGEN AllPrep kits. We developed primary lines (2D and 3D) of colon, thyroid, lung, renal, and liver cancers that were positive for cytokeratin staining. 3D lines were developed from the same cohort of tumor types in both suspended media and Matrigel matrix. Multiple freeze-thaw cycles did not significantly alter the viability and growth of 2D and 3D lines. DNA/RNA recovery was similar to its fresh frozen cohort. In this study, we validated 2D and 3D tissue cultures as methods to corroborate the feasibility of viable cryopreservation of tumor tissue. This proof-of-principle study, if more widely implemented, should improve accessibility of human viable tumor tissue/cells in a time-independent manner for many basic, preclinical, and translational assays.

Reconstruction and Measurement of Irregular Karst Caves Using BLST along the Shield Metro Line

This study investigated the application of the borehole laser scanning technology (BLST) method in the detection of both dry and water-filled karst caves. In order to solve the problem of excessive laser attenuation during the detection, we designed a test for the characteristics of multiwavelength laser attenuation in water-filled karst caves and studied the influence exerted by various factors, including different wavelengths, different laser power levels, different suspended media, and effect of turbidity on the attenuation coefficient. During the test, we discovered the existence of a “blue-green window” with low turbidity and a “near infrared window” with high turbidity in karst cave water environments. Based on the general survey results of drilling and comprehensive geophysical prospecting, a quantitative method using targeted drilling was proposed to detect the spatial morphology of karst caves in complex environments. We also investigated the effects of complex environmental factors such as suspended media and high turbidity on the laser detection distance and accuracy in karst caves, and established a quantitative matching model of laser wavelengths, laser power, and complex environmental parameters. Based on this, we obtained the best acquisition mode for detecting lasers in different karst development environments. A high-precision, three-dimensional visualized model of a real karst cave was established to quantitatively obtain the characteristic parameters, such as accurate position, three-dimensional shape, space volume, and cave filling type, which was applied to the detection of karst caves along the Jinan subway line.

Use of Tethered Hydrogel Microcoatings for Mesenchymal Stem Cell Equilibrium, Differentiation, and Self-Organization into Microtissues.

Therapeutic adult mesenchymal stem cells (MSCs) lose multipotency and multilineage specialization in culture and after transplantation due to the absence of complex biological architecture. Here, it is shown that a transient ultrathin covering of permeable biomaterial can be differentially formulated to either preserve multipotency or induce multidifferentiation. Accordingly, populations of single, spherical MSCs in suspended media with high selectivity and specificity can be coated. Assembly of single, double, and triple hydrogel layers at MSC membranes is initiated by first attaching MSC-specific immunoglobulins onto CD90 or Stro-1 receptors and UEA-1 and soybean lectins. A secondary biotinylated immunoglobulin is targeted for avidin binding, which becomes an attractor for biotinylated alginate or hyaluronate, which are subsequently stiffened and gelled, in situ around the entire cell surface. Alginate microcoatings permeated with mobile BMP-2-induced osteospecialized tissue, vascular endothelial growth factor (VEGF) induced microcapillary formation, while microcoatings, with selected basement membrane proteins, preserve the multipotent phenotype of MSCs, for continuing rounds of culture and directed specialization. Furthermore, forced packing of microcoated MSC populations creates prototypical tissue compartments: the coating partially simulating the extracellular matrix structures. Remarkably, microcoated MSC clusters show a tremendous simulation of a common embryological tissue transformation into the epithelium. Thus, confinement of free morphology exerts another control on tissue specialization and formation.

Relaxation time: a proton NMR-based approach as a metric to measure reactivity of engineered nanomaterials

The toxicological impact of engineered nanoparticles in environmental or biological milieu is very difficult to predict and control because of the complexity of interactions of nanoparticles with the varied constituents in the suspended media. Nanoparticles are different from their bulk counterparts due to their high surface area-to-volume ratio per unit mass, which plays a vital role in bioavailability of these nanoparticles to its surroundings. This study explores how changes in the spin-spin nuclear relaxation time can be used to gauge the availability of surface area and suspension stability of selected nanoparticles (CuO, ZnO, and SiO2), in a range of simulated media. Spin-spin nuclear relaxation time can be mathematically correlated to wetted surface area, which is well backed up by the data of hydrodynamic size measurements and suspension stability. We monitored the change in spin-spin relaxation time for all the nanoparticles, over a range of concentrations (2.5 –100 ppm) in deionized water and artificial seawater. Selective concentrations of nanoparticle suspensions were subjected for temporal studies over a period of 48 hrs to understand the concept of spin-spin nuclear relaxation time-based reactivity of nanoparticle suspension. The nanoparticles showed high degree of agglomeration, when suspended in artificial seawater. This was captured by a decrease in spin-spin nuclear relaxation time and also an increment in the hydrodynamic size of the nanoparticles.

Synthesis and Characterization of Surface Modification of TiO<sub>2</sub> Nanoparticles for Electrophoretic Display

TiO2 and carbon black inorganic pigments having opposite charges have been typically used for white and black image in the electronic ink display technique, respectively. However, since TiO2has a relatively high density, the density mismatch between nanoparticles and the dielectric medium causes severe sedimentation problem in the suspended media. In order to change its surface from hydrophilic to hydrophobic and lower its density, TiO2was grafted by γ-Methacryloxypropyl trimethoxy silane (KH570), and then coated with poly(methyl methacrylate) (PMMA) via a dispersion polymerization method prior to being used for an electronic ink material. In order to improve their mobility, a charge control agent was also added to the suspension of synthesized nanoparticles in the dielectric medium. The KH570-grafted TiO2nanoparticles and the TiO2/KH570/PMMA nanoparticles were characterized by fourier transform-infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Density of TiO2/KH570/PMMA nanoparticles was found to be decreased. Thermal properties of the composite particles were analyzed by thermogravimetric analysis (TGA).

Recognition of water masses according to geochemical signatures in the Central Mediterranean sea: Y/Ho ratio and rare earth element behaviour

This study reports the results of geochemical investigations carried out in the Strait of Sicily (Central Mediterranean Sea) during the oceanographic cruise BANSIC 2000, focusing on the area around the Pantelleria Island. We evaluate the interface processes between dissolved phase and suspended particulate matter in the water columns on the basis of Y/Ho ratio and rare earth elements and yttrium distributions that are suitable to trace the occurrence of different water layers in Central Mediterranean Area. The main source of trace elements to the sea water system was recognized in the atmospheric fallout, while different scavenging mechanisms among Y and rare earth elements occur. Cation exchange at the dissolved phase–suspended media interface is driven by their external electronic configurations as monitored through the Y/Ho ratios, shape, and amplitude of the tetrad effects calculated along the water columns. The shape and amplitude of the tetrad effects in bottom waters suggest that the preferential Y scavenging from deep water layers depends on the hydrothermal activity in the seafloor. Here, Y is surface-complexed through the formation of inner-sphere complexes; Ho and other heavy rare earth elements are sorbed onto suspended particulate matter surfaces as weak outer-sphere complexes; these materials have a montmorillonite like nature; and preferential incorporation medium rare earth elements in crystal structures of biogenic carbonates is suggested by the relationship between the Eu anomaly and the nutrient contents of water masses.

Electrophoretic response of poly(methyl methacrylate) coated TiO 2 nanoparticles

A microcapsule-based electronic ink display technique, which uses the microencapsulation of electrophoretic dispersion, is being developed for direct-view portable displays. Microcapsules of titanium dioxide (TiO 2) electrophoretic nanoparticle suspension were prepared using amino precondensates via in-situ polymerization. The amino prepolymers were synthesized from melamine-urea formaldehyde resin at 60 °C. However, since TiO 2 has a relatively high density (4.28 g/cm 3), the density mismatch causes severe sedimentation problem in the suspended media. In order to lower its density, TiO 2 was coated with poly(methyl methacrylate) via a dispersion polymerization method prior to being used for an electronic ink material. In order to improve their mobility, a charge control agent was also added to the suspension of synthesized nanoparticles in the dielectric medium. Electrophoretic mobility of the synthesized particles was investigated via electrophoretic light scattering. The morphology of the synthesized microcapsule was also characterized by optical microscopy, and scanning electron microscopy.

Viscous fingering patterns of silica suspensions in polymer solutions: effects of viscoelasticity and gravity

Viscous fingering patterns of silica suspensions in polymer solutions, where polymer chains are adsorbed on silica particles, were investigated by pushing air or nitrogen gas in the radial Hele-Shaw cell. Fingering patterns of the stable silica suspensions showed a systematic change from tip-splitting to side branched patterns with an increase in free polymer concentration in suspended media, irrespective of silica content. Such changes in the pattern morphology were similar to those of polymer solutions with the corresponding concentration. The finger growth rate almost increased with a power law of the ratio of the injection pressure and effective shear viscosity, but the exponent was in disagreement with Darcy's law modified by taking into account shear thinning effects. The finger width was followed with the power law of the elasticity of the silica suspension, but the resulting exponent was much larger than that predicated by existing theory. The fingering pattern of the unstable silica suspensions under terrestrial gravity conditions was the tip-splitting type, whereas under microgravity conditions the tip-splitting pattern was slightly suppressed and the fingers were narrower, indicating that sedimentation no longer occurred. For the stable silica suspensions the tip-splitting pattern was much suppressed and the side-branching appeared, irrespective of the gravity conditions. Furthermore, the finger growth rate in microgravity conditions was somewhat faster than that in normal conditions due to less convection induced by gravity.