Stabilization of Calcium Oxalate Precursors during the Pre- and Post-Nucleation Stages with Poly(acrylic acid)

In this work, calcium oxalate (CaOx) precursors were stabilized by poly(acrylic acid) (PAA) as an additive under in vitro crystallization assays involving the formation of pre-nucleation clusters of CaOx via a non-classical crystallization (NCC) pathway. The in vitro crystallization of CaOx was carried out in the presence of 10, 50 and 100 mg/L PAA by using automatic calcium potentiometric titration experiments at a constant pH of 6.7 at 20 °C. The results confirmed the successful stabilization of amorphous calcium oxalate II and III (ACOII and ACO III) nanoparticles formed after PNC in the presence of PAA and suggest the participation and stabilization of polymer-induced liquid-precursor (PILP) in the presence of PAA. We demonstrated that PAA stabilizes CaOx precursors with size in the range of 20–400 nm. PAA additive plays a key role in the in vitro crystallization of CaOx stabilizing multi-ion complexes in the pre-nucleation stage, thereby delaying the nucleation of ACO nanoparticles. Indeed, PAA additive favors the formation of more hydrated and soluble phase of ACO nanoparticles that are bound by electrostatic interactions to carboxylic acid groups of PAA during the post-nucleation stage. These findings may help to a better understanding of the pathological mineralization resulting in urolithiasis in mammals.

Occurrence, environmental implications and risk assessment of Bisphenol A in association with colloidal particles in an urban tropical river in Malaysia

Phase distribution of emerging organic contaminants is highly influential in their presence, fate and transport in surface water. Therefore, it is crucial to determine their state, partitioning behaviour and tendencies in water environments. In this study, Bisphenol A was investigated in both colloidal and soluble phases in water. BPA concentrations ranged between 1.13 and 5.52 ng L−1 in the soluble phase and n.d-2.06 ng L−1 in the colloidal phase, respectively. BPA was dominant in the soluble phase, however, the colloidal contribution ranged between 0 and 24% which implied that colloids can play a significant role in controlling BPA’s transportation in water. Urban and industrial areas were the main sources of BPA while forest areas displayed lower levels outside the populated domains. pH levels were between 6.3 and 7.4 which might have affected BPA’s solubility in water to some extent. The particle size distribution showed that the majority of the particles in river samples were smaller than 1.8 µm in diameter with a small presence of nanoparticles. Zeta potential varied between − 25 and − 18 mV, and these negative values suggested instability of particles. Furthermore, BPA was positively correlated with BOD, COD and NH3–N which might indicate that these organic compounds were released concurrently with BPA. RQ assessment showed low levels of risk towards algae and fish in the study area.

Diafiltration affects the gelation properties of concentrated casein micelle suspensions obtained by filtration

Using membrane filtration it is possible to selectively concentrate proteins and, in the case of microfiltration, concentrate casein micelles. During filtration, water is often added and this practice, called diafiltration, causes further release of permeable components and maintains filtration efficiency. Filtration causes changes in composition of the protein as well as the soluble phase, including soluble calcium, which is a critical factor controlling the gelation properties of the casein micelles in milk. It was hypothesized that concentrates obtained using membrane filtration with or without diafiltration would have different gelation behavior. To test this hypothesis, two concentrates of similar casein micelle volume fraction were prepared, using spiral wound polymeric microfiltration membranes with a 800 kDa molecular weight cutoff, with or without diafiltration. The concentrates showed a gelation behavior comparable to that of skim milk, with a similar gelation time and with a higher firmness, due to the higher number of protein linkages in the network. In contrast, the hydrolysis of κ-casein by chymosin and casein aggregation were inhibited in diafiltered casein micelle suspensions. When the concentrates were recombined with the original skim milk to a final concentration of 5% protein, which re-established a similar soluble phase composition, differences in gelation behavior were no longer observed: both treatments showed similar gelation time and gel firmness. These results confirmed that membrane filtration can result in concentrates with different functionality, and that ionic environmental conditions are critical to the aggregation behavior of casein micelles. This is of particular significance in industrial settings where these fractions are used as a way to standardize proteins in cheese making.

Hydrothermal treatment of sugars to obtain high-value products

In the present work, the degradation of different sugars, such as lactose, cellobiose, sucrose, galactose, glucose, fructose and xylose, was performed in batch reactor with subcritical water at temperature of 250?C and reaction time of 1, 5 and 15 min. The yields of water-soluble phase, acetonesoluble phase, solid residue and gases were determined. The influence of reaction time and difference in sugar structure on the yield of phases and conversion of sugars was studied. Sugars with keto- and furanose structures were less stable than aldo- and pyranose-sugars. The most stable sugars were aldo-hexoses (galactose and glucose). The water-soluble fraction, which is composed of sugars and their derivatives, was analyzed by HPLC using RI and UV detectors. The detected degradation products by HPLC were: 5-hydroxymethylfurfural (5-HMF), furfural, erythrose, sorbitol, 1,6-anhydroglucose, glycolaldehyde, glycerlaldehyde, 1,3-dihydroxyacetone, pyruvaldehyde, formic, levulinic, lactic, oxalic and succinic acids.

Occurrence, Distribution and Ecological Risk of Bisphenol Analogues in the Surface Water from a Water Diversion Project in Nanjing, China

Due to the widespread use of bisphenol analogues (BPs) as alternatives to bisphenol A (BPA), considerable attention for health risk has been shown in aquatic ecosystems. The occurrence and distribution of six BPs were researched in a soluble phase (<10−3 μm), colloidal phase (10−3 μm to 1 µm), and suspended particulate matter (SPM >1 µm) in a water diversion project of Nanjing, China. Except for bisphenol Z, all BPs were detected in two or three phases, where the total concentrations of detected BPs were 161–613 ng/L, 5.19–77.2 ng/L, and 47.5–353 ng/g for the soluble phase, colloidal phase, and SPM, respectively. Among the detected compounds, BPA is still the dominant BPs in the soluble and colloidal phases, which is followed by bisphenol-S , while bisphenol-AF was the major contaminant in SPM, followed by BPA. The mean contribution proportions of colloids were 1–2 orders of magnitude higher than SPM, which suggests that colloids have a clear impact on regulating BPs’ environmental behaviors. In terms of spatial distribution, the water diversion project could reduce the pollution levels of BPs, which might further affect the ecological security of the Yangtze River.

Occurrence, Distribution and Ecological Risk of Bisphenol Analogues in The Surface Water from A Water Diversion Project in Nanjing, China

Because of the widespread use of bisphenol analogues (BPs) as the alternatives to bisphenol A (BPA), they have attracted considerable attention for health risk in aquatic ecosystems. The occurrence and distribution of six BPs were researched in soluble phase (&lt; 5 kDa), colloidal phase (5 kDa to 1 &micro;m) and suspended particulate matter (SPM &gt; 1 &micro;m) in a water diversion project of Nanjing, China. Except for bisphenol Z, all BPs were detected in the two or three phases, the total concentrations of detected BPs were 161-613 ng/L, 5.19-77.2 ng/L and 47.5-353 ng/g for the soluble phase, colloidal phase and SPM, respectively. Among the detected compounds, BPA still the dominant BPs in the soluble and colloidal phases, followed by BPS, while BPAF was the major contaminant in SPM, followed by BPA. The mean contribution proportions of colloids were 1-2 orders of magnitude higher than SPM, suggesting that colloids have an obvious impact on regulating BPs&rsquo; environmental behaviors. In terms of spatial distribution, although the water diversion project could reduce the pollution levels of BPs, which might further affect the ecological security of the Yangtze River.

The Effect of Dissolved Organic Matter (DOM) on the Release and Distribution of Endocrine-Disrupting Chemicals (Edcs) from Sediment under Hydrodynamic Forces, A Case Study of Bisphenol A (BPA) and Nonylphenol (NP)

Endocrine-disrupting chemicals (EDCs) that exist in the aquatic system bring severe environmental risks. In this study, we investigate the dissolved organic matter (DOM) effect on the release and distribution of EDCs under varied hydrodynamic conditions. A water chamber mesocosm was designed to simulate the hydrodynamic forces in a shallow lake. The contents of bisphenol A (BPA) and nonylphenol (NP) in colloid-bound and soluble phases were measured under four increasing hydrodynamic intensities that were 5%, 20%, 50%, and 80% of the critical shear stress. The total BPA and NP contents in overlying water grew linearly with the hydrodynamic intensity (R2 = 0.997 and 0.987), from 108.28 to 415.92 ng/L of BPA and 87.73 to 255.52 ng/L of NP. The exponential relationships of EDC content and hydrodynamic intensity in soluble phase (R2 = 0.985 of BPA and 0.987 of NP) and colloid phase (R2 = 0.992 of BPA and 0.995 of NP) were also detected. The DOM concentrations in colloid-bound phase (cDOM) and in soluble phase (sDOM) were measured and the linear relationships with BPA content (R2 = 0.967 of cDOM and 0.989 of sDOM) and NP content (R2 = 0.978 of cDOM and 0.965 of sDOM) were detected. We analyzed the ratio (αDOM) of sDOM and cDOM that grew logarithmically with the hydrodynamic intensity (R2 = 0.999). Moreover, the ratio (αEDCs) of BPA and NP contents in soluble and colloid-bound phases varied differently with αDOM. The results suggested that BPA tended to be in the soluble phase and NP tended to be in the colloid-bound phase due to the increasing value of αDOM.

Rate of Drug Coating Dissolution Determines In-Tissue Drug Retention and Durability of Biological Efficacy

Two different drug-coated balloons (DCBs) possessing different coating formulations were compared for rate of coating dissolution in vitro, in addition to tissue drug concentration and histological responses of treated vascular tissue in vivo, to determine if the rate of drug bioavailability to vascular tissue can impact the degree and duration of the observed pharmacological response to locally delivered drug. In vitro dissolution comparison demonstrated that a urea/paclitaxel-based coating formulation (IN.PACT™ Admiral™) released drug from solid to soluble phase at a slower and constant rate, yielding approximately 7% solubilized drug in 24 h. In contrast, a coating formulated from polysorbate/sorbitol/paclitaxel (Lutonix™) released 51% of solid phase drug to soluble phase in 1 h of dissolution with the remainder solubilizing in 24 h. In vivo evaluation of tissue drug concentration of both products showed significantly different tissue pharmacokinetic profile, with a higher concentration of paclitaxel in tissue at 90 days with a urea-based formulation excipient. Histological comparison of smooth muscle cell loss in response to drug exposure revealed contrasting trends of smooth muscle cell loss from 28 to 90 days with significantly higher response to drug observed at 90 days with the urea-based formulation. Rapid dissolution of drug from the polysorbate/sorbitol coating formulation was associated with an early increase in local cellular response to drug which diminished over 90 days with clearance of local drug from tissue. Sustained long-term drug-in-tissue concentration associated with the urea-based formulation demonstrated sustained pharmacological activity at 90 days, suggesting that slow coating dissolution provides a sustainable long-term tissue response.