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Studies investigating the mechanical stability of lithium disilicate-strengthened aluminosilicate glass-ceramic that do not require sintering after milling compared with other computer-aided design and computer-aided manufacturing (CAD-CAM) materials are lacking.The purpose of this in vitro study was to investigate the flexural strength of CAD-CAM zirconia, lithium disilicate, and lithium disilicate-strengthened aluminosilicate glass-ceramics with and without fatigue conditions.Specimens (N=90, n=15) (12×4×3 mm) from the following CAD-CAM materials were prepared and polished: lithium disilicate glass-ceramic (IPS e.max CAD); lithium disilicate-strengthened aluminosilicate glass-ceramic (N!ce); and zirconium dioxide ceramic (IPS e.max ZirCAD). All specimens were divided into 2 subgroups: immediate testing without aging and simulation of aging by using a mastication simulator for 1 200 000 cycles (5 °C-55 °C). Thereafter, flexural strength testing was performed by using a universal testing machine (1 mm/min) on nonaged and aged specimens. The data were evaluated by using nonparametric 2-way ANOVA and Wilcoxon rank post hoc tests (α=.05).Both the material type and aging significantly affected the results (P.001). The interaction was not significant (P.05). Under nonaged conditions, zirconium dioxide ceramic (1136 ±162 MPa) showed significantly higher mean ±standard deviation flexural strength (P.001) than lithium disilicate (304 ±34 MPa) and lithium disilicate-strengthened aluminosilicate glass-ceramic (202 ±17 MPa). The glass-ceramic groups were also significantly different from each other (P.001). After aging, zirconium dioxide (1087.9 ±185.3 MPa) also presented significantly higher mean ±standard deviation flexural strength (P.001) than lithium disilicate (259 ±62 MPa) and lithium disilicate-strengthened aluminosilicate glass-ceramic (172 ±11 MPa) (P.001). Aging significantly decreased the flexural strength of lithium disilicate (14.6%) (P=.03) and lithium disilicate-strengthened aluminosilicate glass-ceramic (14.5%) (P=.01) but had minimal effect on the zirconium dioxide ceramic (4.3%) (P=.29).Among the tested CAD-CAM materials, the mechanical performance of lithium disilicate-strengthened aluminosilicate glass-ceramic was comparable with that of lithium disilicate and considerably lower than that of zirconia. Aging decreased the flexural strength of both lithium disilicate and lithium disilicate-strengthened aluminosilicate glass-ceramic.

Constructing lightweight and porous adsorbents which can effectively remove dye contaminants is of great significance in the field of the sewage treatment. In this work, anisotropic cellulose nanofibril (CNF) composite sponges assisted by rectorites are fabricated through directional freeze-drying. The resulted composite sponge exhibits the superior saturated adsorption capacity and removal efficiency of 120.0 mg/g and 96.1% for methylene blue (MB), respectively, which is better than the pure CNF sponge and rectorite powders. This is attributed to the strong electrostatic interaction between CNFs and MB, and good cation exchange property of rectorites inside the three-dimensional (3D) highly porous composite sponge. The MB adsorption process of the composite sponge fits to the pseudo-second-order kinetic model and the Langmuir isotherm model well, which is affected by both boundary layer and intraparticle diffusion, resulting in a theoretical maximum adsorption capacity of 214.6 mg/g. Moreover, it also possesses a selective adsorption capacity for anionic and cationic dyes, which is expected to realize the separation treatment of different dyes according to actual application requirements.

The molecular surface properties of zwitterionic polymer coatings are central to their ultra-low fouling properties and effectiveness as steric stabilizers in concentrated salt solutions. Here, Surface Force Apparatus measurements quantified the molecular forces between end-grafted poly(sulfobetaine) methacrylate thin films and mica, as a function of the chain grafting density and ionic strength. These results demonstrate that, at the ionic strengths considered, end-grafted poly(sulfobetaine) films can be described by models for polymers in good solvent. Parameters determined from data fits to the Milner-Witten-Cates or Dolan and Edwards models for dense or dilute chains, respectively, varied with ionic strength, in ways that reflect poly(sulfobetaine) swelling and the increased excluded volume strength of chain segments. These force measurements provide new insight into how polymer coverage and salt cooperate to regulate repulsive poly(sulfobetaine) steric barriers. These findings have implications for the design of grafted poly(sulfobetaine) as colloidal stabilizers or nonfouling surface coatings.

The behavior and mechanism of Li leaching from lithium aluminum silicate glass-ceramics which can be used as a secondary source of Li using aqueous NaOH solution was investigated. The Li leaching efficiency is increased with increasing concentration of NaOH, specific surface area, and reaction temperature. When leached under optimum conditions, 2 mol/L NaOH, 53 μm particle undersize, 1:10 solid/liquid ratio, 250 r/min stirring speed, 100°C reaction temperature, 12 hr, the Li leaching efficiency was approximately 70%. However, when the leaching experiment was performed for 48 hr, the concentration of Li+ ions contained in the leach liquor decreased from 1160 to 236 mg/L. To investigate the origin of this phenomenon, the obtained leach residue was analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. These analyses show that zeolite was formed around the lithium aluminum silicate glass-ceramics, which affected the leaching of by adsorbing Li+ ions. In addition, using the shrinking-core model and the Arrhenius equation, the leaching reaction with NaOH was found to depends on the chemical reaction of the two reactants, with a higher than 41.84 kJ/mol of the activation energy.

Azomite is a hydrated calcium sodium aluminosilicat rich in rare earth elements. To investigate the dietary effects of Azomite on growth, intestine microbiota and morphology, immunohematological changes and disease resistance, seven diets with Azomite supplementation of 0 (the control), 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 g/kg (A0, A1, A2, A3, A4, A5, A6), were prepared and fed to largemouth bass, Micropterus salmoides (7.96 ± 0.19) for 60 days. The results revealed that the weight gain (WG) increased first and then decreased with the increasing dietary Azomite, and the A2 group presented the highest WG and lowest feed conversion ratio among all the groups. The supplementation of 2.0 g/kg Azomite significantly increased the intestine protease activity, the crude protein of whole body and protein retention (P0.05), and high inclusion of Azomite (6.0 g/kg) significantly reduced the lipid retention (P0.05). The amounts of red blood cells in A5, A6 groups, white blood cells in A3, A5, A6 groups and lymphocyte in A2-A6 groups were all significantly higher than those in the control group (P0.05). In addition, serum superoxide dismutase and catalase activities in A5, A6 groups, and serum alkaline phosphatase and lysozyme activities in A2-A4 groups showed significantly higher values than the control group (P0.05). Intestinal microbiota analysis indicated that the Tenericutes abundance was increased, whereas Proteobacteria abundance was decreased in all Azomite supplemented groups. The villus height in A2-A4 groups, and the villus width in A2 group were significantly higher than those of the control group (P0.05). The cumulative mortality was reduced by the addition of 2.0-5.0 g/kg Azomite after challenging with A. hydrophila (P0.05). In conclusion, proper addition of Azomite in diets improved the growth, intestine morphology, immune response and disease resistance in largemouth bass, and the optimal inclusion was estimated to be 2.0-3.0 g/kg diet.

The aim of the study was to compare production results and quality of meat, as well as histological features of the jejunum in broiler chickens administered feed with 1% addition of zeolite or halloysite, with the addition of aluminosilicates to litter (4.50 kg/m2) throughout the rearing. In the experiment, 300 male broilers were used for 6 wk. They were divided into 3 groups, each of 10 repetitions (10 birds each). Group 1 was a control, halloysite was added to feed and litter in group 2, while zeolite was applied instead of halloysite in group 3. After rearing, 10 selected birds from each group were slaughtered. Selected production properties and degree of footpad dermatitis were examined, and histomorphometric examination of the jejunum was performed. The lowest yield and the highest proportion of neck with skin in the carcass were demonstrated in group 2 (P < 0.05). The lowest percentage of skin with subcutaneous fat was found in group 3 (P < 0.05). A decrease in lightness (L∗) and yellowness (b∗) was demonstrated in group 2, while redness (a∗) was the lowest in group 3 (P < 0.05). Group 2 was characterized by the lowest water-holding capacity in breast muscles, and in group 3, in leg muscles (P < 0.05). In group 3, the highest fat content and the lowest water content in the breast muscles (P < 0.05) were found. The leg muscles in groups 2 and 3 were characterized by the highest a∗, and in group 2, by b∗. The control group had the lowest protein and the highest fat content in leg muscles. In the intestine from group 2, a higher height (P < 0.05) and surface area (P < 0.01) of intestinal villi were found, in comparison to group 3. The width of intestinal villi was higher in groups 2 and 1 than in group 3 (P < 0.05), similarly the depth of intestinal crypts. The addition of zeolite could be proposed because of the obtained production results, while the halloysite had a positive effect on the histomorphometric features of the jejunum.

A bonding material can be acceptable in orthodontics when Shear Bond Strength (SBS) is higher than 5.9Mpa. The aim of our study was to compare the bonding of a metal orthodontic bracket "in vitro" under different types of healthy enamel surface preparations and with two bonding products: the composite and the Resin Modified Glass Ionomer Cement (RMGIC).Premolars preserved in 1% thymol water were bonded on their vestibular and palatal/lingual surfaces with different techniques of bonding and surface preparation: Group 1: Etching+Bonding+Composite, Group 2: Etching+Fuji Ortho LC, Group 3: V-prep+Fuji Ortho LC, Group 4: V-prep+Fuji Ortho LC+Thermocycling. The SBS was measured in Newton on the universal testing machine and the sample was observed under an optical microscope with 10-fold magnification to note the adhesive remnant index score (ARI), before and after thermocycling.120 premolars were used in this study. RMGIC bonding was significantly increased when the surface was prepared at V-prep (P0.001). In these conditions, RMGIC bonding on the buccal surface was similar to that of the composite and superior on the palatal/lingual surface (P=1). After 2 years of aging using a thermocycling machine for simulation, RMGIC bonding significantly decreased (P0.001). The ARI score was significantly lower for the RMGIC group than the composite group (P0.001).RMGIC bonding with V-prep preparation is recommended for palatal/lingual surfaces and for hard-to-dry surfaces. For vestibular surfaces, studies are still needed to recommend bonding with RMGIC instead of composite.

Extracellular DNA (eDNA) is widely present in soil, with potential ecological impacts. Metal cations are naturally present on the surface of soil clay minerals, although the adsorption mechanism of eDNA on clay minerals saturated with metal cations is still not fully understood. The research investigated the adsorption of eDNA, using salmon sperm DNA as a representative, on metal cation (Na+, Ca2+, and Fe3+)-saturated montmorillonites (Mt). Metal cation-saturated Mt have higher adsorption capacities for DNA. Compared with Mt (3500 mg⋅kg−1), the amounts of DNA adsorption on metal cation-saturated Mt (pH = 7.0) were increased by 0.74–5.38 times, and followed the descending order of Fe-Mt > Na-Mt > Ca-Mt > Mt. A temperature of 25 °C was found to be more suitable than 15 and 35 °C for DNA adsorption, while an increasing pH value (3.0–9.0) reduced DNA adsorption on Mt and metal cation-saturated Mt. Microscopic and spectroscopic analyses, together with a model computation technique, confirmed that metal cations saturated on the surface of Mt work like a “cation bridge” linking oxygen atoms in the phosphate groups of DNA and the negatively charged moieties of Mt, which were predominantly bound through electrostatic forces, thus, facilitating DNA adsorption at pH > 5. The results of this investigation provide valuable insight into eDNA adsorption on soil clay minerals and the transport and fate of eDNA in the natural soil environment.

Objectives Understand how cooling protocols control the microstructure and mechanical properties of veneering porcelains. Methods Two porcelain powders were selected, one used to veneer metallic frameworks (VM13) and one for zirconia frameworks (VM9). After the last firing cycle, the monolithic specimens were subjected to two cooling protocols: slow and fast. Flexural strength (FS) was evaluated by three-point beam bending and fracture toughness (KIC) was evaluated by the single-edge V-notch beam (SEVNB) method. Scanning electron microscopy (SEM) was performed to determine the leucite crystal volume fraction (%), particle size, and matrix microcrack density. The results were compared by analysis of variances (ANOVA) and Tukey’s multiple comparison test. Results The mechanical properties were significantly (p Significance Controlled crystallization using slow cooling can be applied as a means of strengthening dental porcelains. However, the benefits of slow cooling may be partially offset by increasing the microcrack density in the glass matrix. To achieve the maximum benefit of slow cooling, it is recommending to develop heat treatments to produce porcelain with fine-grained and homogenously dispersed leucite crystals to achieve minimal glass matrix microcracking.

Chromate is considered to be a toxic contaminant because of its potential to harm animal and human health. In this study, polypyrrole/calcium rectorite clay composites (PPy/Ca-REC composites) were prepared as a potential adsorbent, via in situ polymerization of pyrrole monomer for adsorption of Cr(VI) from aqueous solution. The XRD results indicated that the clay sheets were exfoliated in the prepared composites. SEM results showed good dispersion of the PPy on the clay sheets. The adsorption of Cr(VI) onto the PPy/Ca-REC adsorbent was highly pH-dependent, and the removal efficiency by PPy/Ca-REC composites was much higher than the PPy homopolymer. Adsorption kinetics followed a pseudo-second-order kinetic model with an equilibrium reached within 30–180 min. The adsorption isotherm data were fitted well by the Langmuir isotherm model with the maximum adsorption capacity of 714.29–833.33 mg/g at 25–45 °C. The PPy/Ca-REC composites could be regenerated and reused for three consecutive adsorption-desorption cycles without loss of the original removal efficiency for Cr(VI) removal. Furthermore, the selective adsorption of Cr(VI) was demonstrated in binary adsorption systems with coexisting ions. The mechanisms of Cr(VI) removal containing electrostatic interactions, ionic interaction as well as reduction of Cr(VI) to Cr(III), which could be observed by the XPS results.

A simple method for preparing AgNPs/clay nanocomposites using an adsorption process without any reducing agent was developed in which saponite iron-rich clay was both the solid inorganic support and reducing agent. Silver adsorption by ion exchange of silver ions and saponite ferrous ions resulted in simultaneous silver reduction and silver nanoparticle formation. The maximum loading of silver was determined as 48 mg/g (4.8 mass %). Microscopy showed a homogeneous distribution of sphere-like silver nanoparticles which are composed from smaller crystallites in the form of twinned triangular prisms. The silver particle sizes ranged from 1 nm to 50 nm but predominantly between 8 and 10 nm. The optimum pH range for silver immobilization on saponite support was between 4 and 8. Characterization of the clay samples and synthesized AgNPs/saponite nanocomposites was performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), porosimetry (low temperature nitrogen adsorption-desorption) and zeta potential measurements. The antibacterial activities of raw saponite and AgNPs/saponite nanocomposite samples were tested against clinical relevant Gram-positive Staphylococcus aureus, Staphylococcus epidermidis, and Gram-negative Escherichia coli, Pseudomonas aeruginosa and Proteus mirabilis bacteria by the well diffusion method.

Fe(III)-bearing clay minerals are ubiquitous in the environment. However, the fate of organic contaminants mediated by structural Fe(III) in clays was rarely reported. Here we demonstrated that hydroxylated polychlorinated diphenyl ethers (HO-PCDEs) could be spontaneously formed from the reaction of 2,4,6-trichlorophenol (2,4,6-TCP) with three native smectites: SWy-2, NAu-1, and NAu-2. Further research demonstrated that the structural Fe(III) in smectite is indispensable for the mediation of 2,4,6-TCP to produce chlorophenoxy radical for the subsequent dimerization. The reaction is highly dependent on the relative humidity of the system and the site occupancy of structural Fe(III). Active structural Fe(III) in NAu-2 that played a significant role in the dimerization reaction is relatively more distorted, which would interact strongly with 2,4,6-TCP under low humidity and be inhibited by water molecules. Hence reaction on NAu-2 is suppressed as relative humidity increases. Whereas, water molecules would reduce the activation and reaction energies via forming a hydrogen bond with reaction intermediates, thus enhancing the reactions on SWy-2 and NAu-1 with less water sensitive structural Fe(III). Considering the wide distribution of Fe(III)-bearing smectites in the environment, the contribution of structural Fe(III) for the formation of more toxic dioxin-like compounds from chlorophenols might need to be taken into consideration to evaluate their potential environmental risks.

This research studied the sorption behavior of uranium(VI) onto two different kinds of soils: surface soil and undersurface soil that taken from the depth of 30 m undersurface. The soil samples were collected from a low and medium-level radioactive waste disposal site in the southwest of China. The effects of pH, solid-liquid ratio and contact time on the adsorption behavior were studied by batch adsorption method. The experiment results show that the mineral composition of soil and the speciation of U in natural groundwater are two main influencing factors. Muscovite and clinochlore, two of the main minerals of soil samples, dominate the sorption behavior of uranium onto natural soils at weak acidic and near neutral pH range. Under neutral and weak alkaline conditions, the thermodynamic calculation results show that Ca2+ and CO32− have significant influence on the species of uranium in aqueous solution. The U sorption reduced sharply due to the formation of the CaUO2(CO3)32− (aq) complex. This work provides a better insight of the sorption behavior of uranium onto natural soils, and gives an in-depth understanding about the influence of aqueous and surface speciation.

Soil amendments with zeolite and vermiculite were expected to prevent radiocaesium (137Cs) dissolution and uptake from the soil by plants. In this study, we investigated how zeolite and vermiculite added to soil influence the radiocaesium fixation with ageing. Zeolite and vermiculite were mixed with soil (1 wt%) before or after the addition of carrier-free caesium-137 (137Cs) to soils with different radiocaesium interception potential (RIP), which is related to the capacity of the soil to fix trace radiocaesium. Then, the soils were exposed for repeated wet and dry cycles to accelerate 137Cs immobilization, and its extractability by 1 mol L−1 ammonium acetate was determined before and after 30 dry and wet cycles. Before accelerated ageing (i.e before dry and wet cycles), when 137Cs was adsorbed on the soil before the addition of the amendments, the addition of zeolite and vermiculite caused a decrease in the amount of exchangeable 137Cs in low-RIP soils but an increase in the amount of exchangeable 137Cs in high-RIP soils. The amount of exchangeable 137Cs was significantly decreased after accelerated ageing regardless of the application of amendments. However, radiocaesium fixation with accelerated ageing was partly inhibited by the addition of zeolite, regardless of the RIP values. The 137Cs adsorbed on highly selective sites in zeolite is exchangeable by 1 mol L−1 ammonium acetate. Thus, because a portion of the 137Cs is selectively adsorbed on highly selective sites in zeolite, the redistribution of 137Cs to frayed edge site followed by ageing-induced fixation was likely limited. However, when 137Cs was adsorbed on the soil before the addition of the amendments, the addition of zeolite and vermiculite had little influence on the amount of exchangeable 137Cs. In conclusion, the use of realistic doses of zeolite and vermiculite as agricultural amendments is not effective in enhancing the immobilization of radiocaesium in soil.

Sugar-based biosurfactants are safer and healthier alternatives to synthetic surfactants especially for use in the food industry. In this work, biosurfactants were synthesized via the esterification of lactose with lauric acid in different organic solvents without using lipase or other enzymes. Commercial aluminosilicate zeolite was used as a catalyst. Conversions of up to 92% were obtained for pure lactose and 38% for raw lactose from whey. Surface-active properties including surface tension, interfacial tension, and contact angle were measured. All samples showed surface tensions lower than sodium dodecyl sulfate, SDS (19.59–36.57 mN/m compared to 38.8 mN/m for SDS) and interfacial tensions comparable with it (9.47–12.18 mN/m compared to 4.77 mN/m for SDS). Results showed that aluminosilicate zeolites can be used for the synthesis of lactose esters, which have potential applications as biosurfactants for the food industry featuring low surface and interfacial tensions.

To assess a reliable safety case for future deep underground repositories for highly active nuclear waste the retention of radionuclides by the surrounding host rock must be understood comprehensively. Retention is influenced by several parameters such as mineral heterogeneity and surface roughness, as well as pore water chemistry (e.g., pH). However, the interplay between those parameters is not yet well understood. Therefore, we present a correlative spectromicroscopic approach to investigate sorption of the actinide Cm(III) on: 1) bulk K-feldspar crystals to determine the effect of surface roughness and pH (5.5 and 6.9) and 2) a large feldspar grain as part of a complex crystalline rock system to observe how sorption is influenced by the surrounding heterogeneous mineralogy. Our findings show that rougher K-feldspar surfaces exhibit increased Cm(III) uptake and stronger complexation. Similarly, increasing pH leads to higher surface loading and stronger Cm(III) binding to the surface. Within a heterogeneous mineralogical system sorption is further affected by neighboring mineral dissolution and competitive sorption between mineral phases such as mica and feldspar. The obtained results express a need for investigating relevant processes on multiple scales of dimension and complexity to better understand trivalent radionuclide retention by a potential repository host rock.

Functionalization of natural clay minerals for high value-added pharmaceutical and cosmetic applications receives significant research attention worldwide attributable to a rising demand and ongoing search for green, efficient, economically sustainable and ecofriendly geomaterials. Fibrous clays, i.e. palygorskite and sepiolite, are naturally-occurring hydrated magnesium aluminum silicate clay minerals with 2:1 layer-chain microstructure and one-dimensional nanofibrous morphology. Due to their unique structural, textural and compatibility features, over the past decade, fibrous clays and their organic modified derivatives are increasingly used in the dermopharmaceutical and cosmetic fields as excipients, active agents or nanocarriers to develop novel skin delivery systems or to modify drug release profile for enhanced health effects. This comprehensive review presents the up-to-date information on fibrous clays used in topically-applied products for therapeutic and cosmetic purposes with the focus on their performance-related structural characteristics and the underlying mechanisms. The recent advancement of fibrous clay-based skin delivery systems was summarized in wide range of applications including pelotherapy, wound healing, antimicrobial action, coloration and UV protection. An overview of the commonly used topically-applied dosage forms (powders, hydrogels, films, peloids and Pickering emulsion) as well as the toxicological aspects was also included, which might provide guidance to the design and development of fibrous clay-based skin delivery systems.

A modified sodium bentonite geosynthetic clay liner (GCL) designed for acid-and-alkaline resistance was evaluated for its potential application in the containment of bauxite residue leachate. A modified fluid loss test was employed to quickly evaluate the hydraulic conductivity (k) of the GCL using distilled water, tap water, and four bauxite liquors (BLs, leachate from bauxite residue reservoirs). The effects of swelling capacity of bentonite, prehydration, hydraulic gradient (i), ionic strength (I), and relative abundance of monovalent and multivalent cations (RMD) on the hydraulic conductivity of the GCL were analyzed. The results indicated that the BLs significantly decreased free swell index of the bentonite. As compared to increasing i, prehydration obviously enhanced hydraulic performance of the GCL. The four BLs increased k of the GCL by a factor of 4-12 relative to the tap water permeation condition, and the resultant k exceeded upper limit of 5.0 × 10

After disasters, such as forest fires and oil spills, high levels of benzene (> 1 ppm) can be detected in the water, soil, and air surrounding the disaster site, which poses a significant health risk to human, animal, and plant populations in the area. While remediation methods with activated carbons have been employed, these strategies are limited in their effectiveness due to benzene’s inherent stability and limited retention to most surfaces. To address this problem, calcium and sodium montmorillonite clays were amended with a mixture of chlorophyll (a) and (b); their binding profile and ability to detoxify benzene were characterized using in vitro, in silico, and well-established ecotoxicological (ecotox) bioassay methods. The results of in vitro isothermal analyses indicated that chlorophyll-amended clays showed an improved binding profile in terms of an increased binding affinity (K(f) = 668 vs 67), increased binding percentage (52% vs 11%), and decreased rates of desorption (28% vs 100%), compared to the parent clay. In silico simulation studies elucidated the adsorption mechanism and validated that the addition of the chlorophyll to the clays increased the adsorption of benzene through Van der Waals forces (i. e., aromatic π-π stacking and alkyl-π interactions). The sorbents were also assessed for their safety and ability to protect sensitive ecotox organisms (Lemna minor and Caenorhabditis elegans) from the toxicity of benzene. The inclusion of chlorophyll-amended clays in the culture medium significantly reduced benzene toxicity to both organisms, protecting C. elegans by 98–100% from benzene-induced mortality and enhancing the growth rates of L. minor. Isothermal analyses, in silico modeling, and independent bioassays all validated our proof of concept that benzene can be sequestered, tightly bound, and stabilized by chlorophyll-amended montmorillonite clays. These novel sorbents can be utilized during disasters and emergencies to decrease unintentional exposures from contaminated water, soil, and air.

A new adsorbent that combines mineral vermiculite with the yeast Saccharomyces cerevisiae, was used for Cd2+ removal. The influence of vermiculite presence on the toxic effects of Cd2+ to Saccharomyces cerevisiae yeast was evaluated as a function of the microorganisms' respiratory activity (CO2 production). The Cd2+ toxicity increased with prolonged exposure time reaching the LC50 value of 857 and 489 mg L−1 after 30 and 120 min, respectively. The yeast managed to bioaccumulate 25.0 ± 0.6 mg g−1 of Cd2+ at the initial Cd2+ concentration of 741.9 mg L−1; the maximum Cd2+ adsorption capacity of vermiculite reached 25 ± 5 mg g−1. The addition of the mineral decreased the cations toxic effect; the LC20 value in vermiculite absence attained approximately 200 mg L−1 after 30 min and decreased to 80 mg L−1 after 2 h, while in the bio-mineral system it was at the level of 435 ± 50 mg L−1 without a significant change in time. The mineral provided a superior living environment for the yeast by removing part of the cations, releasing essential microelements and providing a protective, clay hutch-like habitat for the cells, The authors would like to acknowledge the National Centre for Research and Development working under the auspices of the Polish Ministry of Science and Higher Education for financial support from the LIDER XII grant (0074/L-12/2020) and to Associate Laboratory for Green Chemistry – LAQV is financed by national funds from FCT/MCTES (UIDB/50006/2020).

The adsorption mechanism of collectors on minerals is of fundamental importance in the research and development of flotation science and processing technology. To examine the effect of cationic dodecylamine hydrochloride (DDAH), anionic sodium oleate (NaOL) and mixed DDAH/NaOL surfactants with different molar ratios on the adsorption behavior on the muscovite (001) surface, the adsorption mechanism of DDAH, NaOL and their mixture on the muscovite (001) surface in neutral aqueous solution was investigated by molecular dynamics (MD) simulations. The results showed that the cationic DDAH molecules absorb on the muscovite (001) surface by electrostatic interactions and hydrogen bonding, whereas the anionic NaOL molecules cannot independently adsorb on the muscovite surface. Based on the analysis of the density distribution profile, radial distribution function (RDF) and interaction energy between surfactant molecules and muscovite surface, and the root mean square displacement (RMSD) of surfactants on water-muscovite interface, individual DDAH surfactant is a superior collector for the muscovite flotation. The molar ratio of DDAH/NaOL surfactants is found to be a key factor in the flotation response of muscovite. No significant adsorption of 1:2, 1:3 and 1:4 mixed DDAH/NaOL surfactants on the muscovite surface can be detected, while an effective adsorption was observed for the DDAH/NaOL mixture in molar ratios of 1:1, 2:1, 3:1 and 4:1. The cationic DDAH surfactant was determined to play a primary role in the adsorption of the mixed surfactants on the muscovite surface, while the anionic NaOL molecules co-adsorb with the DDAH molecules. The additional micro-flotation experiments under neutral aqueous conditions also showed that the flotation recovery of muscovite was the highest in the presence of DDAH surfactant, which was consistent with the findings derived from MD simulations.

Hyaluronan (HA)-lipid layers on model (mica) surfaces massively reduce friction as the surfaces slide past each other, and have been proposed, together with lubricin, as the boundary layers accounting for the extreme lubrication of articular cartilage. The ability of such HA-lipid complexes to lubricate sliding biological tissues has not however been demonstrated. Here we show that HA-lipid layers on the surface of an intrasynovial tendon can strongly reduce the friction as the tendon slides within its sheath. We find a marked lubrication synergy when combining both HA and lipids at the tendon surface, relative to each component alone, further enhanced when the polysaccharide is functionalized to attach specifically to the tissue. Our results shed light on the lubricity of sliding biological tissues, and indicate a novel approach for lubricating surfaces such as tendons and, possibly, articular cartilage, important, respectively, for alleviating function impairment following tendon injury and repair, or in the context of osteoarthritis. STATEMENT OF SIGNIFICANCE: Lubrication breakdown between sliding biological tissues is responsible for pathologies ranging from dry eye syndrome to tendon-injury repair impairment and osteoarthritis. These are increasing with human longevity and impose a huge economic and societal burden. Here we show that synergy of hyaluronan and lipids, molecules which are central components of synovial joints and of the tendon/sheath system, can strongly reduce friction between sliding biological tissues (the extrasynovial tendon sliding in its sheath), relative to untreated tissue or to either component on its own. Our results point to the molecular origins of the very low friction in healthy tendons and synovial joints, as well as to novel treatments of lubrication breakdown in these organs.

The study presents the results of an analysis of fly ashes produced from burning of solid fuels mixed with municipal waste and assesses the environmental and health risk associated with infiltration of the selected metals to the environment. The phase composition suggests that the material is extremely mixed and diverse. Low-temperature components were mixed with substances formed in high temperatures. The variable composition of waste from different home furnaces with high content of the amorphous phase (which dissolves in water more easily than its crystalline equivalents) may be harmful to the environment and for the people. The dominant elements were silicates and aluminosilicates, such as: quartz, feldspar and plagioclase (albite). Clay minerals (kaolinite and mullite), carbonates (calcite), oxides/oxidehydroxides of iron and sulfate minerals (gypsum and anhydrite) were also abundant. The particles' major constituents were Si, Al, Ca and Fe oxides (85.5%), while S, Mg, Na, K and Ti oxides accounted for 12.6% of the total content. The risk assessment code suggested: Low Risk for As, Co, Cr, Ni, Medium Risk for Cd, Cu and Pb, and High Risk for Zn. Hazard Index (HI) calculated for non-cancerogenic substances for children was 2.35E+00. The total Risk index for children was 4.88E-05. As for adults, HI was 2.42E-01 for women, and 2.89E-01 for men, while the Risk index value was 6.85E-05 for women, and 8.48E-05 for men. The value HI > 1 points to the risk of adverse health impact on children exposed to fly ashes.

Soil clay minerals are effective substrate adsorbents of polycyclic aromatic hydrocarbons (PAHs) in natural soil. The adsorbed PAHs result in long-term contamination of soils. In this paper, a typical PAH phenanthrene (Phe) and nine high purity clay minerals are selected as representative PAH pollutants and adsorbents, respectively. A series of experiments have been conducted to disclose the relationship between the Phe adsorption effect of these clay minerals and their physical properties, including specific surface area (SSA), cation exchange capacity (CEC) and contact angle (CA). Molecular simulation methods are performed to explore the mechanism of clay mineral structure on Phe adsorption at the molecular level. Density functional theory (DFT) calculation suggests that the adsorption of Phe on clay minerals is mainly due to the van der Waals effect. The strength of the O-H-π effect is greater than that of the hydrophobic effect of Phe adsorption. Molecular dynamic (MD) simulations imply that the hydration effect of cations hinders the Phe hydrophobic adsorption by occupying the adsorption sites. Based on the mechanism explored, a simple empirical model is proposed, and the adsorption distribution coefficient Kd of clay mineral and water phases can be precisely predicted by the three physical properties of clay minerals, without rigorous quantitative analysis of soil clay minerals.

The increasing anthropogenic pressure results in environmental pollution and thus adversely affects the integrity of ecosystems. Consequently, various methods of removing pollutants from effluents have been developed and used to minimise this negative impact, with adsorption on clay minerals identified as the most promising approach. This review examines the adsorption of heavy metals, radionuclides, and organic pollutants on clays/clay minerals and their composites under diverse conditions and deals with the applications of these materials in the construction of engineering barriers for waste management. Additionally, we discuss the efficiency and mechanisms of pollutant adsorption on clays subjected to various treatments and modifications while describing the beneficial effects of such modification/treatment on adsorption performance, reusability, and in vivo/in vitro toxicity.

This article reports a facile strategy to detect hexavalent chromium (Cr (VI)) using a naturally formed mineral (kyanite) based fluorometric sensor. Nitrogenous carbon dots have been incorporated into natural kyanite (KYCD) nanoparticles causing a stable bright blue fluorescence compared to its pristine counterpart. This sensing probe structurally stabilizes and resists the agglomeration of carbon dots, thus retaining fluorescence quality for a longer period. The promising bright blue fluorescence has been utilized further to detect Cr (VI) in wastewater and living cells. Ease of synthesis, low cost, and stability of the system offers the benefit for large-scale production, which is convenient for industrial production the sensing probe. The sensor shows high selectivity and sensitivity (LOD and LOQ of 0.11 µM and 0.36 µM respectively in case of linear fitting, whereas 0.26 µM and 0.88 µM respectively for full range plot) towards hexavalent chromium in presence of other interfering elements. A detailed study of photoinduced electron transfer (PET) mediated rapid 'turn off' sensing mechanism was carried out using Time-Dependent Density functional (TDDFT) calculations. The sensing efficacy of the probe remains unaltered under a wide range of pH and can be effective in various water types. Onsite sampling and probing of Cr (VI) in tannery wastewater has been performed to validate its real-life efficiency that yields excellent results. The sensor can effectively detect chromium at a cellular level (HeLa cells) in a similar way as the bright blue fluorescence diminishes in presence of the quenching ion. Experimental in vitro studies along with theoretical docking analysis has been conducted to substantiate such issues and a higher possibility of fluorophore binding was found for Isoleucine (2.9 Å), Serine (2.96 Å), and Glycine (3.16 Å). This biocompatible sensor rapidly senses hexavalent chromium in living cells, which makes this efficient probe a true heavy metal-induced carcinogen sensor.

The interaction behaviors of heavy metals and micaceous minerals are extremely important to understand the environmental behaviors of heavy metals. In this work, the interaction behaviors of Cr(VI) and biotite in the presence and absence of HA were studied combining batch and spectroscopic approaches. Batch experiments showed that biotite had the ability to remove Cr(VI) from the water and the removal markedly increased with decreasing pH. However, sorption of total Cr onto biotite increased with increasing pH (2.0-4.0), whilst quickly decreased above pH ∼ 4.0. It was worth noting that redox process of Cr(VI) to Cr(III), caused by structural Fe(II) on biotite, was another important factor for the high removal of Cr(VI) in a pH range of 2.0-4.0. Ionic strength also influenced Cr(VI) removal that Cr(VI) removal became higher with increasing ion strength. The presence of HA did not show obvious macroscopic effect on Cr(VI) removal, however, HA could cover biotite surface, and promote the sorption of total Cr onto biotite and attenuate the reduction effect caused by Fe(II) on biotite. Spectroscopic approaches, like FT-IR, XRD and XPS further confirmed the existence of Cr(III) on biotite interacting with Cr(VI) and the reduction of Cr(VI) to Cr(III) was drove by the Fe(II) dissolving from biotite to Fe(III). Further, sorption effect and reduction effect competitively contributed to the Cr(VI) removal by biotite, and reduction effect played a more important role at lower pH.

The transport of emerging organic contaminants through the geosphere is often an environmental issue. The sorption of organic compounds slows their transport in soils and porous rocks and retardation is often assessed by extrapolation of batch experiments. However, transport experiments are preferable to strengthen migration data and modelling. In this context, we evaluated the adsorption of various organic acids by means of through-diffusion experiments in a sedimentary clay-rich rock (Callovo-Oxfordian, East of Paris Basin, France). A low diffusivity of organic anions was quantified with effective diffusion coefficients, De, ranged between 0.5 and 7 10−12 m2 s−1. These values indicated an organic anion exclusion. As for chloride, the porosity accessible to organic anions was lower than that of water: ea(organic anions)

Water contamination by multidrug resistant (MDR) enteric bacteria can be considered as the foremost cause of gastrointestinal infections and poses a threat to global public health. Therefore, there is an urgent need to pursue unorthodox techniques with potential of community scale applications for purging of water borne pathogenic bacteria. We communicate visible-light assisted photocatalytic disinfection (PCD) of an enteric MDR bacterium; Enterobacter sp. using Fe-doped ZnO nanoparticles impregnated on Kaolinite (Clay) (ZnO/K). ZnO/K was synthesized by co-precipitation technique and was found to be more effective than Fe-doped ZnO (ZnO) and Kaolinite for PCD process. Analysis from fluorescence microscopy and electron microscopy (FESEM) proposed complete bacterial cell death via PCD due to damage of bacterial cell membrane. Experimental evidences indicated that O2- could be acting as the most significant component in disinfection of MDR Enterobacter sp. in visible-light assisted PCD process in presence of ZnO/K. Considering the experimental data of Resazurin assay, it is proposed that reactive oxygen species (ROS) generated during PCD might have impeded the oxido-reductase enzyme system of the bacteria and hence trammeling its metabolic activity. Crystal structure and particle size of ZnO/K was found to be unaltered during the photocatalytic process indicating its potential for reusability. When ZnO/K was exposed to HCT-116 Human Colorectal Carcinoma cell lines, about 79% cell survivability was noticed. The synthesized material was successful in completely disinfecting the target microorganism in Zebra Fish model, without producing any adverse effects on the Fish itself, further reinforcing its biocompatibility factor. High effectiveness of PCD process using ZnO/K under visible light in disinfecting enteric MDR bacteria, might have promising outcome as an alternative water disinfection technology to prevent the spread of infectious and resistant bacteria without producing any adverse effect on non-specific flora and fauna.

Permeable pavement is an effective tool for improving stormwater hydrology and water quality when sited over soils with high infiltration rates, but its efficacy over less permeable soils is uncertain. This study examined permeable pavement performance when built over a low-conductivity, clay soil. Four parking stalls (50 m2 total area) were retrofitted with permeable interlocking concrete pavement (PICP) to treat 15.2 m2 of contributing impervious area (0.3:1 run-on ratio). Using an elevated underdrain, the site incorporated a 150-mm internal water storage (IWS) zone to increase exfiltration and promote anaerobic conditions for denitrification. From March 2014–April 2015, 22% of influent runoff volume was reduced via exfiltration and evaporation. Inter-event drawdown of the IWS zone created storage to capture and exfiltrate more than 70% of the runoff volume from precipitation events less than 8 mm, and peak flows were significantly reduced (median 84%). Relative to stormwater runoff from a nearby impermeable asphalt reference watershed, the permeable pavement produced significantly lower event mean concentrations (EMCs) of all pollutants except nitrate, which was significantly higher. Permeable pavement effluent and reference watershed runoff were 99%, 68%, and 96% different for total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP), respectively. Significantly lower permeable pavement effluent EMCs for copper (Cu, 79%), lead (Pb, 92%) and zinc (Zn, 88%) were also observed. The median effluent concentrations of TN (0.52 mg/L), TP (0.02 mg/L), and TSS (7 mg/L) were all very low relative to the literature. Sampling of nitrogen species in the IWS zone 12, 36, 60, and 84 h post-rainfall was done to better understand mechanisms of nitrogen removal in permeable pavement; results indicated denitrification may be occurring in the IWS zone. Effluent pollutant load from the permeable pavement was at minimum 85% less than from nearby untreated asphalt runoff for TP, TSS, Cu, Pb, and Zn, and was 73% less for TN. Permeable pavements built over low-permeability soils with internal water storage can considerably improve long-term hydrology and water quality.

Objectives To process novel leucite glass-ceramics and test the effects of surface treatment and resin bonding on the biaxial flexural strength (BFS) and shear bond strength (SBS). Methods Alumino–silicate glasses were ball-milled, and heat treated to form leucite glass-ceramics (LG-C, OLG-C), then sintered into ingots. Ingots were heat extruded into a refractory mould to form disc specimens (1.3 × 14 mm diameter). IPS e.max® was used as a commercial comparison. Glass-ceramic test groups were sandblasted (Groups. 1, 4, 6), sandblasted, etched and adhesively bonded (Groups. 2, 5, 7) or lapped, etched and adhesively bonded (Groups. 3, 8). Specimens were adhesively bonded with Monobond S, followed by the application of Variolink II® cement and light curing. BFS testing was at 1 mm/min and SBS testing at 0.5 mm/min. Samples were characterised using XRD, SEM and profilometry. Results XRD confirmed tetragonal leucite in LG-C/OLG-C and lithium disilicate/lithium orthophosphate in IPS e.max®. Mean BFS (MPa (SD)) were: Gp1 LG-C; 193.1 (13.9), Gp2 LG-C; 217.7 (23.0), Gp3 LG-C; 273.6 (26.7), Gp4 OLG-C; 255.9 (31); Gp5 OLG-C; 288.6 (37.4), Gp6 IPS e.max®; 258.6 (20.7), Gp7 IPS e.max®; 322.3 (23.4) and Gp8 IPS e.max®; 416.4 (52.6). The Median SBS (MPa) were Gp1 LG-C; 14.2, Gp2 LG-C (10 s etch); 10.6 and Gp3 IPS e.max®; 10.8. Mean surface roughness was 5–5.1 μm (IPS e.max®) and 2.6 μm (LG-C). Significance Novel leucite glass-ceramics with reduced flaw size and fine microstructures produced enhanced BFS and SBS by resin bonding. These properties may be useful for the fabrication of minimally invasive aesthetic and fracture resistant restorations.

Introduction NeoMTA Plus (Avalon Biomed Inc, Bradenton, FL) is a tricalcium silicate material similar to the first mineral trioxide aggregate product, ProRoot MTA (Dentsply Sirona, York, PA), but with improvements such as decreased setting time, increased ion release, increased water sorption, and nonstaining radiopacifiers. Quick-Set2 (Avalon Biomed Inc) is a newly formulated calcium aluminosilicate material that has a faster setting time and increased acid resistance and is nonstaining. The purpose of this study was to compare the healing of pulpal and periapical tissues in dogs after exposure to NeoMTA Plus and Quick-Set2 after pulpotomy and root-end surgery procedures. Methods Seventy-two teeth (36 for each procedure) in 6 beagle dogs received pulpotomy or root-end surgery using either NeoMTA Plus or Quick-Set2. The dogs were sacrificed at 90 days, and the teeth and surrounding tissues were prepared for histologic evaluation. Sixty teeth were evaluated and scored histologically (29 with pulpotomies and 31 with root-end resections). Specimens were scored for inflammation, quality and thickness of dentin bridging, pulp tissue response, cementum and periodontal ligament formation, and apical bone healing. Results Both materials displayed favorable healing at 90 days. The only significant difference was the quality of dentin bridge formation in pulpotomies using NeoMTA Plus compared with Quick-Set2. Conclusions Quick-Set2 and NeoMTA Plus had similar effects on inflammation, pulp response, periodontal ligament and cementum formation, and apical tissue healing in dogs. NeoMTA Plus had superior dentin bridge quality compared with Quick-Set2.

Nitrate has been recognized as a global threat to environmental health. In this regard, the hyporheic zone (saturated media beneath and adjacent to the stream bed) plays a crucial role in attenuating groundwater nitrate, prior to discharge into surface water. While different nitrate removal pathways have been investigated over recent decades, the adsorption capacity of hyporheic sediments under natural conditions has not yet been identified. In this study, the natural attenuation capacity of the hyporheic-sediments of the Ghezel-Ozan River, located in the north-west of Iran, was determined. The sampled sediments (from 1 m below the stream bed) were characterized via XRD, FT-IR, BET, SEM, BJH, and Zeta potential. Nitrate adsorption was evaluated using a batch experiment with hyporheic pore-water from each study site. The study was performed in the hyporheic sediments of two morphologically different zones, including Z1 located in the parafluvial zone having the clay sediment texture (57.8% clay) with smectite/Illite mixed layer clay type and Z2 located in the river confluence area containing silty clay sediment texture (47.6% clay) with smectite/kaolinite mixed layer clay type. Data obtained from the batch experiment were subjected to pseudo-first order, pseudo-second order, intra-particle diffusion, and Elovich mass transfer kinetic models to characterize the nitrate adsorption mechanism. Furthermore, to replicate nitrate removal efficiencies of the hyporheic sediments under natural conditions, the sampled hyporheic pore-waters were applied as initial solutions to run the batch experiment. The results of the artificial nitrate solution correlated well with pseudo-second order (R2>95%; in both Z1 and Z2) and maximum removal efficiencies of 85.3% and 71.2% (adsorbent dosage 90 g/L, pH = 5.5, initial adsorbate concentration of 90 mg/L) were achieved in Z1 and Z2, respectively. The results of the nitrate adsorption analysis revealed that the nitrate removal efficiencies varied from 17.24 ± 1.86% in Z1 during the wet season to 28.13 ± 0.89% in Z2 during the dry season. The results obtained by this study yielded strong evidence of the potential of hyporheic sediments to remove nitrate from an aqueous environment with great efficiency.

A field-scale trial was conducted to investigate the remediation effects of sepiolite on Cd-polluted paddy soils under different moisture managements, using a series of variables (pH and extractable Cd of soil, plant Cd concentration, plant nutrition and enzyme activity in soil). Results revealed that soil pH increased significantly after sepiolite addition, which promoted the reduction in extractable Cd in soil. After applying 0.5-2.5% sepiolite into soil, due to higher pH and lower TCLP Cd concentration, brown rice Cd reduced by 17-67% under continuous flooding, 14-62% under conventional irrigation, and 13-61% under wetting irrigation (p 0.05). The activities of phosphatase and invertase increased compared with unamended soil (p 0.05). The available phosphorus in clay treated soil showed a remarkable raise, with a maximum increase by 14.5%, 16.9% and 18.1% under three moisture managements (p 0.05). The increasing values of enzyme activity and then plant nutrition in soil revealed that clay application improved the ecological condition of Cd-contaminated paddy soil. The sepiolite application in combination with continuous flooding provided an efficient and safe remediation technology for Cd-polluted rice field.

Contamination of arid and semi-arid ecosystems by toxic heavy metals is a serious concern due to its impact on growth and productivity of crop and health risk through food chain. Therefore, the aims of this investigation were to study the impact of inorganic (i.e. nano hydroxyapatite, NHA and polyacrylamide, PAM) and organic (i.e. sugar beet factory lime, SBFL and biochar, BI) soil amendments on maize productivity grown in contaminated silty clay (i.e. fluvial, lacustrine) and sandy (i.e. marine) alkaline soils. In addition, the effect of those amendments on the content of heavy metals in plant organs and their fractions in alkaline soils at harvest as well as human health risk assessment were investigated. Application of amendments, particularly SBFL, followed by NHA and BI resulted in an improvement for maize growth and its productivity in comparison to PAM application and untreated soil. However, application of NHA significantly reduced the mobile fraction of Cd, Pb and Ni in soil and consequently in different maize organs, followed by application of SBFL and BI in comparison to untreated soil or soil treated with PAM. Additionally, transfer factors and health risk of metals were lesser when NHA and SBFL were applied into soil than those obtained from application of PAM. In conclusion, applications of NHA, SBFL and BI into contaminated alkaline soils with toxic heavy metals can be considered a vital option for ameliorating such soils from the view of environment and sustainable management in terms of heavy metals immobilization and reducing the metals content in plant organs.

In this work, the removal of different types of emerging pollutants (four perfluoroalkyl compounds, two preservatives, three surfactants and nine pharmaceutical compounds) from aqueous solution by adsorption onto two novel synthetic clays, a high-charge swelling mica (Na-Mica-4) and an organo-functionalized mica (C18-Mica−4), was evaluated. Na-Mica-4 and C18-Mica− 4 were prepared and characterized by X-Ray diffraction, Zeta potential, specific surface area, thermogravimetric analysis and transmission electron microscopy, before and after adsorption experiments. The influence of the aqueous sample pH, salt addition and extraction time in the removal were evaluated. The results showed the high adsorption affinity of C18-Mica-4 for most of the emerging pollutants analysed after a removal time of 24 h (14 out of 18 pollutants were effectively removed [70–100%]). A high correlation was observed between the log Kow of the selected emerging pollutants and the adsorption onto C18-Mica-4. The results also indicate that adsorption occurs in the interlayer space. While the removal rates with Na-Mica-4 were in the range 8–97% after seven days, some of the compounds, perfluorobutanoic acid and most of pharmaceutically active compounds, were not adsorbed onto the high-charge mica. C18-Mica− 4 was effectively used for the removal of contaminants from four types of water samples.

Various xenobiotics interact with biological membranes, and precise evaluations of the molecular interactions between them are essential to foresee the toxicity and bioavailability of existing or newly synthesized molecules. In this study, surface forces apparatus (SFA) measurement and Langmuir trough based tensiometry are performed to reveal nanomechanical interaction mechanisms between potential toxicants and biological membranes for ex vivo toxicity evaluation. As a toxicant, polyhexamethylene guanidine (PHMG) was selected because PHMG containing humidifier disinfectant and Vodka caused lots of victims in both S. Korea and Russia, respectively, due to the lack of holistic toxicity evaluation of PHMG. Here, we measured strong attraction (Wad ∼4.2 mJ/m2) between PHMG and head group of biological membranes while no detectable adhesion force between the head group and control molecules was measured. Moreover, significant changes in π-A isotherm of 1,2-Dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) monolayers were measured upon PHMG adsorption. These results indicate PHMG strongly binds to hydrophilic group of lipid membranes and alters the structural and phase behavior of them. More importantly, complementary utilization of SFA and Langmuir trough techniques are found to be useful to predict the potential toxicity of a chemical by evaluating the molecular interaction with biological membranes, the primary protective barrier for living organisms.

Though abundant studies have targeted the characterization of heavy metal adsorption by either clay minerals or bacteria, to date, minimal literature exists which specifically assesses bacteria-clay mineral interactions in the context of metal immobilization. The adsorption of Pb onto montmorillonite, Pseudomonas putida, and their 1:1, 2:1, 6:1 and 12:1 mass ratio composites were investigated by using a combination of atomic force microscope (AFM), X-ray diffraction (XRD), surface complexation modeling (SCM), Pb-LIII edge extended X-ray absorption fine structure (EXAFS) spectroscopy and isothermal titration calorimetry (ITC). The SCM and EXAFS demonstrated that Pb ions coordinate with phosphoryl and carboxyl functional groups on bacteria at low and high concentrations, respectively. The ITC analysis found adverse enthalpy values for Pb adsorption to permanent (−2.91 kJ/mol) and variable charge sites (6.93 kJ/mol) on montmorillonite. The ternary bridging model, EXAFS and ITC provide molecular and thermodynamic evidences for the formation of enthalpy driven (−4.74 kJ/mol) ternary complex (>AlO-Pb-PO4) in the composites. The proportion for the bridging structures increased at pH > 5 and high bacterial mass ratios. The formation of ternary complex did not result in the enhanced adsorption of Pb on the composites, but promoted the allocation of Pb on the mineral fraction. The results obtained from SCM, EXAFS and ITC may provide an essential assumption for predicting the speciation and fate of Pb in soils and associated environments.

Evaluate if etching protocols affect superficial/internal microstructural integrity of CAD/CAM ceramic materials.Sixty blocks (3×3×3mm) of IPS/Empress-LEU, IPS/e.max-LDC (Ivoclar-Vivadent) and Enamic-PIC (VITA) were used. Lateral surfaces from each block were isolated with Teflon strip and petroleum jelly to keep them untouched. Specimens were distributed into 6 groups (n=10): 1. no treatment (C); 2. hydrofluoric acid (HF) 5%, 20s (HF5%20s); 3. HF5%60s; 4. HF10%20s; 5. HF10%60s; 6. Monobond EtchPrime (MBEP). Surface roughness (Sa) and 3D profile were obtained using a confocal-laser-optical-microscope (LEXT OLS 4000, Olympus), while element ratios (Si/K for LEU and LDC; Si/C for PIC) were recorded using energy dispersive spectroscopy (EDS). Superior (treated) and lateral (non-treated) surfaces were analyzed using scanning electron microscopy (SEM) (JSM 5600 LV, JEOL). Etching depth was measured on lateral surfaces. Data were submitted to ANOVA-One-Way and Tukey test (α=0.05).For LEU, only HF10% treatments produced statistically different roughness values and Si/K ratios compared to C group. Regarding LDC and PIC, groups HF5%60s and HF10% showed higher roughness values than C group. In the case of PIC, all treatments (except MBEP) produced lower Si/C ratios than C group. All treatments (except MBEP) produced higher etching depth values than C group for all materials, being HF10%60s the highest (LEU:403.2±11.4μm; LDC:617.4±75.7; PIC:291.6±6.5μm). HF10% produced more aggressive etching morphology patterns on superior and lateral surfaces (SEM). Treatments MBEP and HF5%20s, produced the least aggressive structural alterations. Acid etching produces superficial and internal alterations on ceramics' structural configuration.Aggressive etching protocols of glass-ceramics may cause internal material loss, consequently, milder etching is recommended to treat those materials before adhesion procedures.

Bacterial infection is a major problem world-wide, especially in wound treatment where it can severely prolong the healing process. In this study, a double drug co-delivery elastic antibacterial nanocomposite was developed by combining ciprofloxacin (CPX) and polymyxin B sulfate-loaded halloysite clay nanotubes (HNTs-B) into a gelatin elastomer. CPX nanoparticles which act against both gram positive and gram-negative bacterium were dispersed directly in the matrix, and polymyxin B sulfate was loaded in HNTs and then distributed into the matrix. The effect of CPX and HNTs-B content on the physical properties, cytotoxicity, fibroblast adhesion and proliferation, in vitro drug release behavior and anti-bacterial properties were systematically investigated. The ciprofloxacin crystals and HNT-B were distributed in the matrix uniformly. The HNTs in the drug loading system not only enhanced the matrix' tensile strength but also slowed down the release rate of the high dissoluble polymyxin B sulfate. When the amount of HNT in the matrix increased, the thermal stability and tensile strength also increased but the polymyxin B sulfate release rate decreased because the HNTs prevented the drug release inside. All the nanocomposites exhibited antimicrobial activity against both gram-negative and gram-positive bacteria with the dual combination of drugs released from the nanocomposites. Furthermore, this kind of gelatin-based nanocomposites possesses higher water-absorbing quality, low cytotoxicity, adaptable biodegradability and good elasticity which can satisfy the requirements for an ideal biomaterial for use in wound healing applications.

Aniline aerofloat (AAF), a high-toxic organic flotation reagent, is widely used in mineral processing industry. However, little information on its environmental fate is available. AAF sorption to four types of agricultural soils at low concentrations (1–10 mg/L) was investigated using batch experiments. AAF sorption kinetics involved both boundary layer diffusion and intraparticle diffusion, following pseudo-second-order kinetics with equilibrium time within 120 min. Both Langmuir and Freundlich models fitted well the AAF sorption with the former better. Sorption of AAF to soils was a spontaneous and favorable physical sorption that was controlled by ion bridge effect and hydrophobic interaction that was related to van der Waals force and π-π coordination based on FTIR analyses. AAF sorption was remarkably affected by soil constituents, positively correlating with the contents of organic matter and clay. The relatively higher logKoc values (3.53–4.66) of AAF at environmental concentrations (1–5 mg/L) imply that soils are serving as a sink of AAF from beneficiation wastewater, posing great potential risks to environment and human health.

The effects of soil components such as clay minerals and as humic acids, as well as co-existing metals and polycyclic aromatic hydrocarbons, on desorption and mobility are examined. Three types of artificially blended clay and clay mineral mixtures (pure kaolinite, kaolinite + sand and kaolinite + sand + bentonite), each with different humic acid content, were tested for desorption and mobility of acenaphthene, fluorene and fluoranthene by three extracting solutions CaCl2 (0.01 M) and EDTA (0.01M) with non-ionic surfactants (Tween 80 and Triton X100). Heavy metals (Ni, Pb and Zn) were also studied for desorption and mobility. The influence of co-present metals on simultaneous desorption and mobility of PAHs was investigated as well. The results showed that 80% in clay mineral mixtures containing no sand, while in the same soils containing ∼40% sand, the desorption exceeded 90%. Heavy metals, as well as increasing humic acids content in the clay mineral mixtures, decreased the desorption and mobility of PAHs, especially for soils containing no sand, and for fluoranthene compared with fluorene and acenaphthene.

The main aim of the present study was to design pH-sensitive nanocomposite hydrogel beads, based on carboxymethyl cellulose (CMC) and montmorillonite (Mt)-propranolol (PPN) nanohybrid, and evaluate whether the prepared nanocomposite beads could potentially be used as oral drug delivery systems. PPN-as a model drug-was intercalated into the interlayer space of Mt clay mineral via the ion exchange procedure. The resultant nanohybrid (Mt-PPN) was applied to fabricate nanocomposite hydrogel beads by association with carboxymethyl cellulose. The characterization of test samples was performed using different techniques: X-Ray Diffraction (XRD), IR spectroscopy (FT-IR), thermal gravity analysis (TGA), and scanning electron microscopy (SEM). The drug encapsulation efficiency was evaluated by UV-vis spectroscopy, and was found to be high for Mt/CMC beads. In vitro drug release test was performed in the simulated gastrointestinal conditions to evaluate the efficiency of Mt-PPN/CMC nanocomposite beads as a controlled-release drug carrier. The drug release profiles indicated that the Mt-PPN/CMC nanocomposite beads had high stability against stomach acid and a sustained- and controlled-release profile for PPN under the simulated intestinal conditions.

Statement of problem Anterior shade matching is an essential factor influencing the esthetics of a ceramic restoration. Dentists face a challenge when the color of an implant abutment creates an unsatisfactory match with the ceramic restoration or neighboring teeth. Purpose The purpose of this in vitro study was to evaluate the influence of abutment material and ceramic thickness on the final color of different ceramic systems. Material and methods Four experimental and control ceramic specimens in shade A3 were cut from IPS e.max CAD, IPS Empress CAD, and VITA Suprinity PC blocks. These specimens had thicknesses of 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm, respectively, for the experimental groups, and 4 mm for the controls. Background abutment specimens were fabricated to yield 3 different shades: white zirconia, yellow zirconia, and titanium at a 3-mm thickness. All 3 ceramic specimens in each thickness were placed in succession on different abutment backgrounds with glycerin optical fluid in between, and the color was measured. A digital spectrophotometer was used to record the specimen color value in the Commission Internationale De L'eclairage (CIELab) color coordinates system and to calculate the color difference (ΔE) between the control and experimental groups. The Kruskal-Wallis test was used to analyze the effect of ceramic thickness on different abutments, and the pair-wise test was used to evaluate within the group (α=.05). Results The color differences between the test groups and the control decreased with increasing ceramic thickness for every background material. In every case, significant differences were found between 1.0- and 2.5-mm ceramic thicknesses. Only certain 2.5-mm e.max CAD, VITA Suprinity PC, and Empress CAD specimens on yellow-shade zirconia or VITA Suprinity PC on titanium were identified as clinically acceptable (ΔE Conclusions Increasing ceramic restoration thickness over the abutment background decreased the color mismatch. Increasing the thickness of ceramic on a yellow-shaded zirconia abutment rather than on titanium or white zirconia yielded a more esthetic color for the whole restoration.

We report a facile methodology for the synthesis of inorganic-organic hydrogels based on integrative assembly of aminopropyl magnesium phyllosilicate (aminoclay) and sodium salt of hyaluronic acid. The viscoelastic materials produced by electrostatic interactions and crosslinking of hyaluronan in the presence of exfoliated synthetic organoclay results in the formation of gel-like behavior retaining a high amount of water. This was confirmed by a rheological study revealing significant dominance of the elastic response over the entire deformation frequency range used. The mechanical strength of the aminoclay-hyaluronan hydrogels was found to be higher than that for related materials based on poly(vinylpyrrolidone)-aminoclay hydrogels.

Here, we reported a fast, low-cost, and effective fabrication method of large-area and rough halloysite nanotubes (HNTs) coatings by thermal spraying of HNTs ethanol dispersions. A uniform HNTs coating with high transparence is achieved with tailorable surface roughness and thickness. Compared with normal cells, the tumor cells can be captured effectively with high capture yield by the HNTs coatings (expect HeLa cells), which is attributed to the enhanced topographic interactions between HNTs coating and cancer cells. HNTs coating formed from 2.5% ethanol dispersions shows the highest tumor cells capture yeild (90%), which is related to the appropriate roughness and anti-EpCAM conjugation. The capture yield of HNTs coating towards MCF-7 cells can be further improved to 93% within 2h under dynamic shear using a peristaltic pump. The capture yield increases with the incubation time, and the flow rate with 1.25mL/min leads to the maximum capture yield. The HNTs coatings are also effective for capture of tumor cells spiked in artificial blood samples and blood samples from patients with metastatic breast cancer. More than 90% targeted MCF-7 cells and very small amounts of white blood cells are captured by the anti-EpCAM conjugated HNTs coatings from a blood sample. HNTs are further loaded anticancer drug doxorubicin (DOX) and then thermally sprayed into coatings. The MCF-7 cells captured on DOX loaded HNTs coating display significant membrane rupture characteristic and only 3% cell viability after 16h. The high capture efficiency of tumor cells by HNTs coating fabricated by the thermal spraying method makes them show promising applications in clinical circulating tumor cells capture for early diagnosis and monitoring of cancer patients. The high killing ability of the DOX loaded HNTs coating can also be designed as an implantable therapeutic device for preventing tumor metastasis.

Halloysites (tubular aluminosilicate) are introduced as inexpensive natural nanoparticles that form and stabilize oil-water emulsions. Pickering emulsification can proceed with energies low enough to be afforded by ocean turbulence and the stability of droplets extends over more than a week. The oil/water interface is shown to be roughened and bacteria, which are added for oil degradation, are better attached to such oil droplets than to droplets without halloysites. The metabolic activity of Alcanivorax borkumensis, alkanotrophic bacteria widely distributed in marine environments, is enhanced by halloysite addition. A halloysite-based dispersant system is therefore environmentally friendly and promising for further optimization. The key elements of the described formulations are natural clay nanotubes, which are abundantly available in thousands of tons, thus making this technology scalable for environmental remediation.

The effect of Sodium Bentonite (SB) enriched diet on growth performance, innate immune response, and disease resistance in stinging catfish, Heteropneustes fossilis against Aeromonas hydrophila is reported. The infected fish fed with 5% SB had the maximum weight gain diet (PWG %) and specific growth rate (SGR %) were 26% and 29% when compared to 14% and 17% with 10% diet. Similarly the phagocytic activity increased significantly when infected fish were fed with 5% or 10% SB diets during the experimental period; the complement, respiratory burst and lysozyme activities were also significantly enhanced on weeks 2 and 4. The lower cumulative mortality (10% and 15%) was observed when the infected fish were fed with 5% and 10% SB diets for 30 days. The results suggest that the infected H. fossilis after administration of 5% and 10% SB enriched diets for 30 days had significantly improved growth performance, innate immunity, and disease resistance against A. hydrophilla. Hence, sodium bentonite can be used as a feed additive to stimulate immunity and for disease resistance in the effective production of economically valuable freshwater catfish, H. fossilis.

Smectite clay nanoparticles are implicated in the retention of antimicrobials within soils and sediments; these clays are also inspected as drug carriers in physiological systems. Cation exchange is considered the primary adsorption mechanism of antimicrobials within smectite nanopores. However, a dual role of acid-base chemistry and adsorptive structures is speculated by recent studies. Using the prototypical smectite clay montmorillonite, we employed a combination of X-ray diffraction (XRD), nuclear magnetic resonance, attenuated total reflectance-Fourier transform infrared spectroscopy, and molecular dynamics simulations to investigate the interlayer nanopore trapping of two structurally-different fluoroquinolone (FQ) antimicrobials with similar acid-base chemistry: ciprofloxacin (a first-generation FQ) and moxifloxacin (a third-generation FQ). Greater sorption at pH 5.0 than at pH 7.0 for both FQs was consistent with cation-exchange of positively-charged species. However, the clay exhibited a near twofold higher sorption capacity for moxifloxacin than for ciprofloxacin. This difference was shown by the XRD data to be accompanied by enhanced trapping of moxifloxacin within the clay interlayers. Using the XRD-determined nanopore sizes, we performed molecular dynamics simulations of thermodynamically-favorable model adsorbates, which revealed that ciprofloxacin was adsorbed parallel to the clay surface but moxifloxacin adopted a tilted conformation across the nanopore. These conformations resulted in more slowly-exchanged than quickly-exchanged Na complexes with ciprofloxacin compared with moxifloxacin. These different Na populations were also captured by 23Na nuclear magnetic resonance. Furthermore, the simulated adsorbates uncovered different complexation interactions that were corroborated by infrared spectroscopy. Therefore, beyond acid-base chemistry, our findings imply that distinct adsorbate structures control antimicrobial trapping within clay nanopores, which can promote persistence in environmental matrices and stable delivery in biological systems.

Objective The objective of the present study is to understand the role of yttria stabilized zirconia (YSZ) in achieving the desired spectrum of clinically relevant mechanical properties (hardness, elastic modulus, fracture toughness and brittleness index) and chemical solubility of mica glass ceramics. Methods The glass–zirconia mixtures with varying amounts of YSZ (0, 5, 10, 15 and 20 wt.%) were ball milled, compacted and sintered to obtain pellets of glass ceramic-YSZ composites. Phase analysis was carried out using X-ray diffraction and microstructural characterization with SEM revealed the crystal morphology of the composites. Mechanical properties such as Vickers hardness, elastic modulus, indentation fracture toughness and chemical solubility were assessed. Results Phase analysis of sintered pellets of glass ceramic-YSZ composites revealed the characteristic peaks of fluorophlogopite (FPP) and tetragonal zirconia. Microstructural investigation showed plate and lath-like interlocking mica crystals with embedded zirconia. Vickers hardness of 9.2 GPa, elastic modulus of 125 GPa, indentation toughness of 3.6 MPa·m1/2, and chemical solubility of 30 μg/cm2 (well below the permissible limit) were recorded with mica glass ceramics containing 20 wt.% YSZ. Significance An increase in hardness and toughness of the glass ceramic-YSZ composites with no compromise on their brittleness index and chemical solubility has been observed. Such spectrum of properties can be utilised for developing a machinable ceramic for low stress bearing inlays, onlays and veneers.