Sluggish and Ion-Resilient Behavior of Interfacial Aqueous Layer on Single-Layer Graphene Oxide: Insights from In Situ Atomic Force Microscopy.

Understanding interfacial interactions of graphene oxide (GO) is important to evaluate its colloidal behavior and environmental fate. Single-layer GO is the fundamental unit of GO colloids, and its interfacial aqueous layers critically dictate these interfacial interactions. However, conventional techniques like X-ray diffraction are limited to multilayer systems and are inapplicable to single-layer GO. Therefore, our study employed atomic force microscopy to precisely observe the in situ dynamic behaviors of interfacial aqueous layers on single-layer GO. The interfacial aqueous layer height was detected at the subnanometer level. In real-time monitoring, the single-layer height increased from 1.17 to 1.70 nm within 3 h immersion. This sluggish process is different from the rapid equilibration of multilayer GO in previous studies, underscoring a gradual transition in hydration kinetics. Ion strength exhibited negligible influence on the single-layer height, suggesting a resilient response of the interfacial aqueous layer to ion-related perturbations due to intricate ion interactions and electrical double-layer compression. Humic acid led to a substantial increase in the interfacial aqueous layers, improving the colloidal stability of GO and augmenting its potential for migration. These findings hold considerable significance regarding the environmental behaviors of the GO interfacial aqueous layer in ion- and organic-rich water and soil.

In vitro release modeling of beta-carotene from Bene oleosome and electrosprayed Quince seed hydrocolloids loaded with oleosomes containing beta-carotene.

This research aimed to extract oleosome from the Bene kernel as a carrier of beta-carotene (3, 5, and 10 % w/w) and then use oleosomes in the Quince seed gum (QSG) electrosprayed nanoparticles for the sustained release of beta-carotene in food simulant. Oleosomes loaded with 5 % w/w beta-carotene had the highest encapsulation efficiency (94.53 % ± 1.23 %) and were used at 1, 3, and 5 % w/w in the QSG electrosprayed nanoparticles. Electrospray feed solutions containing 5 % oleosomes loaded with beta-carotene had the highest zeta potential (-34.45 ± 0.58 mV) and the lowest surface tension (23.47 ± 1.10 mN/m). FESEM images showed that with the increase of oleosomes up to 3 % w/w, the average size of the electrosprayed particles decreases. The Fourier transform infrared (FTIR) test proved the presence of protein in the oleosomes and their successful extraction from Bene seeds. Differential scanning calorimetry (DSC) and FTIR proved the successful entrapment of beta-carotene in the oleosomes structure and the successful placement of oleosomes containing beta-carotene in the electrosprayed nanoparticles. The predominant driving force involving the release of beta-carotene from the designed structures in food simulants was the Fickian release mechanism. The Peleg model was introduced as the best model describing the beta-carotene release.

Aggregation, retention and transport of γ-MnO2 nanoparticles in water-saturated porous media: Impact on the immobility of thallium.

Nano-scale Mn oxides can act as effective stabilizers for Tl in soil and sediments. Nevertheless, the comprehensive analysis of the capacity of MnO2 to immobilize Tl in such porous media has not been systematically explored. Therefore, this study investigates the impact of γ-MnO2, a model functional nanomaterial for remediation, on the mobility of Tl in a water-saturated quartz sand-packed column. The mechanisms involved are further elucidated based on the adsorption and aggregation kinetics of γ-MnO2. The results indicate that higher ionic strength (IS) and the presence of ion Ca(II) promote the aggregation of γ-MnO2, resulting from the reduced electrostatic repulsion between particles. Conversely, an increase in pH inhibits aggregation due to enhanced interaction energy. γ-MnO2 significantly influences Tl retention and mobility, with a substantial fraction of γ-MnO2-bound Tl transported through the column. This might be attributed to the high affinity of γ-MnO2 for Tl through ion exchange reactions and precipitation at the surface of γ-MnO2. The mobility of Tl in the sand column is influenced by the γ-MnO2 colloids, exhibiting either inhibition or promotion depending on the pH, IS, and cation type of the solution. In solutions with higher IS and Ca(II), the mobility of Tl decreases as γ-MnO2 colloids tend to aggregate, strain, and block, facilitating colloidal Tl retention in porous media. Although higher pH reduces the mobility of individual Tl, it promotes the mobility of γ-MnO2 colloids, facilitating a substantial fraction of colloidal-form Tl. Consequently, the optimal conditions for stabilizing Tl by γ-MnO2 involve either high IS and low pH or the presence of competitive cations (e.g., Ca(II)). These findings provide new insights into Tl immobilization using MnO2- and Mn oxide-based functional materials, offering potential applications in the remediation of Tl contamination in soil and groundwater.

Inhibiting effects of humic acid on iron flocculation hindered As removal by electro-flocculation on air cathode iron anode.

Activated carbon air cathode combined with iron anode oxidation-flocculation synergistic Arsenic (As) removal was a new groundwater purification technology with low energy consumption and high efficiency for groundwater with high As concentration. The presence of organic matter such as humic acid (HA) had ambiguous effects on formation of organic colloids in the system. The effects of the particle size distribution characteristics of these colloids on the formation characteristics of flocs and the efficiency of As purification was not clear. In this work, we used five different pore size alumina filter membranes to separate mixed phase solutions and studied the corresponding changes in iron and arsenic concentrations in the presence and absence of humic acid conditions. In the presence of HA, the arsenic concentration of < 0.05 µm particle size components was 1.01, 1.28, 3.07, 7.69, 2.85 and 1.24 times of that in the absence of HA. At the same time, the arsenic content in 0.05-0.1 µm and 0.1-0.45 µm particle size components was also higher than that in the system without HA, which revealed that the presence of HA hindered the flocculation behavior of As distribution to higher particle sizes in the early stage of the reaction. The presence of HA affected the flocculation rate of iron flocs from small to large particle size fractions and it had limited effect on the behavior of large-size flocs in adsorption of As. These results provide a theoretical basis for targeted, rapid, and low consumption synergistic removal of arsenic and organic compounds in high arsenic groundwater.

Liquid-liquid phase separation (LLPS) in DNA and chromatin systems from the perspective of colloid physical chemistry.

DNA is a highly charged polyelectrolyte and is prone to associative phase separation driven by the presence of multivalent cations, charged surfactants, proteins, polymers and colloids. The process of DNA phase separation induced by positively charged species is often called DNA condensation. Generally, it refers to either intramolecular DNA compaction (coil-globule transition) or intermolecular DNA aggregation with macroscopic phase separation, but the formation of a DNA liquid crystalline system is also displayed. This has traditionally been described by polyelectrolyte theory and qualitative (Flory-Huggins-based) polymer theory approaches. DNA in the cell nucleus is packed into chromatin wound around the histone octamer (a protein complex comprising two copies each of the four histone proteins H2A, H2B, H3 and H4) to form nucleosomes separated by linker DNA. During the last decade, the phenomenon of the formation of biomolecular condensates (dynamic droplets) by liquid-liquid phase separation (LLPS) has emerged as a generally important mechanism for the formation of membraneless organelles from proteins, nucleic acids and their complexes. DNA and chromatin droplet formation through LLPS has recently received much attention by in vitro as well as in vivo studies that established the importance of this for compartmentalisation in the cell nucleus. Here, we review DNA and chromatin LLPS from a general colloid physical chemistry perspective. We start with a general discussion of colloidal phase separation in aqueous solutions and review the original (pre-LLPS era) work on DNA (macroscopic) phase separation for simpler systems with DNA in the presence of multivalent cations and well-defined surfactants and colloids. Following that, we discuss and illustrate the similarities of such macroscopic phase separation with the general behaviour of LLPS droplet formation by associative phase separation for DNA-protein systems, including chromatin; we also note cases of segregative association. The review ends with a discussion of chromatin LLPS in vivo and its physiological significance.

Early complications in scoliosis surgery and relation to preoperative factors: A single-center retrospective study.

In this study, we aimed to investigate the perioperative complications of the patients who underwent scoliosis surgery in our hospital and the factors that may affect the outcome. Between 2014 and 2018, scoliosis patients recorded data was examined retrospectively. Age, gender, height, body weight, comorbidity, Cobb index, scoliosis etiology, operation time, preoperative and postoperative hemoglobin, hematocrit, leukocyte, blood urea nitrogen, creatinine, coagulation value, operation time, level of instrumentation, intraoperative and postoperative blood loss, blood transfusion, intraoperative fluid administration, preoperative pulmonary function test values, blood gas values, urine outputs, hospital (LOS) and post anesthesia care unit stays, complications and mortality rates were examined. The files of 77 patients (48 female, 29 male) were retrospectively analyzed. The average age was 19.54 ±â€…16.32 years and 98.7% were elective surgery. The mean of LOS was 13.55 ±â€…9.13 days. As the preoperative hematocrit value decreases, LOS increases significantly. In patients with chronic obstructive pulmonary disease, smokers and high ASA scores, LOS is prolonged in patients with previous operations. As intraoperative colloid administration increased, crystalloid and blood products increased, it was also observed that the amount of crystalloid increased LOS. As the amount of intraoperative colloid or red blood cell administration increases, the duration of surgery and anesthesia increases, also increases the duration of post anesthesia care unit. Compared to patients with complications (n = 29) to the patients without complications (n = 47), it was found that they had longer anesthesia, and surgery times, also longer LOS times (P < .05). Our study showed that chronic obstructive pulmonary disease in the preoperative period, smoking, high ASA score, excessive use of colloid, prolonged duration of surgery and anesthesia, and long intubation durations increase the length of hospital stay. Preoperative comorbidity is directly related to postoperative complications and causes longer hospitalization after reconstructive scoliosis surgery.

Size-resolved distribution of trace elements in lysimeter soil solutions under contrasting long-term agricultural management to assess their bioavailability.

The chemical species of trace elements (TEs) in agricultural soils is highly variable under diverse conditions, requiring tools with clear resolution and minimal disturbance for exploration. A novel surgical (316L) stainless steel (SS) lysimeter with a 5 µm pore size was developed to collect field soil solutions. The size-resolved distribution of TEs were characterized into total (nitric acid digestion), particulate (0.45-5 µm), dissolved (<0.45 µm), colloidal (1 kDa to 0.45 µm), and mainly ionic (<1 kDa) fractions in the lysimeter soil solutions. Total concentrations of TEs (dry weight basis) in acid digested Gray Luvisolic soils were analyzed. Most TEs in lysimeter soil solutions were present in particulate phases, relevant to their geochemical affinities and occurrences in soil minerals. Among dissolved fractions, As, Ba, Co, Li, Mn, Tl, and V existed as mainly ionic species in the soil solutions. Copper, Pb, Al, Th, and U showed variable associations with dissolved organic matter (DOM) and/or inorganic colloids among agricultural treatments. Inorganic NPKS or NKS fertilizer applications with lower pH (5.25-5.74) enhanced mobility and potential bioavailability of Ba, Co, Li, Mn, and Pb present in mainly ionic species, compared with other locations (pH 5.82-6.37). Manure application exhibited a dual effect, potentially increasing bioavailability for As, Tl, and V due to probably enhanced cation exchange capacity (CEC), while also facilitating specific adsorption of Cu and U on DOM, potentially reducing their bioavailability depending on DOM molecular weight. Colloidal and ionic Al and Th concentrations were higher in forest soils than agricultural soils, with extremely low potential bioavailability of Th attributed to strong precipitation with inorganic colloids and adsorption on DOM. The lysimeter sampling and size fractionation method provided a clear insight into agricultural effects on TE distributions and enhancing understanding of agricultural soil health in terms of TE bioavailability in situ.

Mentha piperita silver nanoparticle-loaded hydrocolloid film for enhanced diabetic wound healing in rats.

OBJECTIVE: To investigate the role of Mentha piperita silver nanoparticle-loaded carbopol gel for enhanced wound healing in a diabetic rat model. This research further aims to explore bioactive compounds derived from Mentha piperita obtained from high altitude. METHOD: Methanolic extracts of Mentha piperita (MP), Mentha spicata (MS) and Mentha longifolia (ML) were used to synthesise silver nanoparticles (AgNP). AgNP synthesis was confirmed by ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The antioxidant activity was assessed by 2, 2-diphenyl-1-picrylhydrazyl (DDPH) assay. Antiglycation potential was determined by measuring the fluorescent advanced glycation end products. The bioactive compound identified in the Mentha piperita methanolic (MPM) fraction through electrospray ionisation tandem mass spectrometric analysis (ESI-MS) was responsible for the highest antiglycation. The effects of MPM and MPM.AgNP-loaded Carbopol (Sanare Lab, India) on wound healing were compared in male, alloxan-induced, diabetic albino rats (200-250g), divided into control and treated groups. Effects on wound healing were assessed via histopathology. RESULTS: UV-Vis and FTIR confirmed NP synthesis with peaks for flavonoids and polyphenols. SEM and XRD explored the cubical, 30-63nm crystalline NP. The maximum antioxidant and antiglycation potential was observed in order of; MP.AgNP>MS.AgNP>ML.AgNP. The highest antioxidant activity was observed by methanolic and aqueous MP.AgNPs (88.55% and 83.63%, respectively) at 2mg.ml-1, and (75.16% and 69.73%, respectively) at 1mg.ml-1, compared to ascorbic acid (acting as a positive control, 90.01%). MPM.AgNPs demonstrated the best antiglycation potential of 75.2% and 83.3% at 1mg.ml-1 and 2mg.ml-1, respectively, comparable to positive control (rutin: 88.1%) at 14 days post-incubation. A similar trend was observed for antimicrobial activity against Bacillus subtilis, Micrococcus luteus and Escherichia coli with an inhibition zone of 21mm, 21.6mm and 24.6mm. Rosmarinic acid was the active compound present in Mentha piperita, as identified by ESI-MS. MPM.AgNP-loaded Carbopol resulted in 100% wound closure compared with control at 20 days post-wounding. In the treatment group, re-epithelialisation was achieved by day 18, compared with 25 days for the positive control group. CONCLUSION: MPM.AgNP-loaded Carbopol demonstrated safer and more effective biological properties, hence accelerating the diabetic excision wound healing process in alloxan-induced diabetic rats.

Optimization of cardiopulmonary bypass prime fluid to preserve microcirculatory perfusion during on-pump coronary artery bypass graft surgery: PRIME study protocol for a double-blind randomized trial.

BACKGROUND: Acute microcirculatory perfusion disturbances and organ edema are important factors leading to organ dysfunction during cardiac surgery with cardiopulmonary bypass (CPB). Priming of the CPB system with crystalloid or colloid fluids, which inevitably leads to hemodilution, could contribute to this effect. However, there is yet no optimal evidence-based strategy for this type of priming. Hence, we will investigate different priming strategies to reduce hemodilution and preserve microcirculatory perfusion. METHODS: The PRIME study is a single-center double-blind randomized trial. Patients undergoing elective coronary artery bypass graft surgery with CPB will be randomized into three groups of prime fluid strategy: (1) gelofusine with crystalloid, (2) albumin with crystalloid, or (3) crystalloid and retrograde autologous priming. We aim to include 30 patients, 10 patients in each arm. The primary outcome is the change in microcirculatory perfusion. Secondary outcomes include colloid oncotic pressure; albumin; hematocrit; electrolytes; fluid balance and requirements; transfusion rates; and endothelial-, glycocalyx-, inflammatory- and renal injury markers. Sublingual microcirculatory perfusion will be measured using non-invasive sidestream dark field video microscopy. Microcirculatory and blood measurements will be performed at five consecutive time points during surgery up to 24 h after admission to the intensive care unit. DISCUSSION: PRIME is the first study to assess the effect of different prime fluid strategies on microcirculatory perfusion in cardiac surgery with CPB. If the results suggest that a specific crystalloid or colloid prime fluid strategy better preserves microcirculatory perfusion during on-pump cardiac surgery, the current study may help to find the optimal pump priming in cardiac surgery. TRIAL REGISTRATION: ClinicalTrials.gov NCT05647057. Registered on 04/25/2023. CLINICALTRIALS: gov PRS: Record Summary NCT05647057, all items can be found in the protocol.

Fluorescence-activated cell sorting (FACS) for purifying colloidal clusters.

Colloidal particles are considered to be essential building blocks for creating innovative self-assembled and active materials, for which complexity beyond that of compositionally uniform particles is key. However, synthesizing complex, multi-material colloids remains a challenge, often resulting in heterogeneous populations that require post-synthesis purification. Leveraging advances brought forward in the purification of biological samples, here we apply fluorescence-activated cell sorting (FACS) to sort colloidal clusters synthesized through capillary assembly. Our results demonstrate the effectiveness of FACS in sorting clusters based on size, shape, and composition. Notably, we achieve a sorting purity of up to 97% for clusters composed of up to 9 particles, albeit observing a decline in purity with increasing cluster size. Additionally, dimers of different colloids can be purified to over 97%, while linear and triangular trimers can be separated with up to 88% purity. This work underscores the potential of FACS as a promising and little-used tool in colloidal science to support the development of increasingly more intricate particle-based building blocks.

The Efficacy of Radiolabeling the Albumin in Egg Whites with 99mTc-Sulfur Colloid.

In 2009, the Society of Nuclear Medicine and Molecular Imaging published a standardized protocol guideline for gastric emptying scintigraphy that contains specific instructions on the exact meal and preparation procedure. Previous research has shown that the standardized meal and proper preparation of the meal for gastric emptying scintigraphy are not being adopted by some facilities. This research explores the differences of radiolabeling in the method of preparation of 99mTc-sulfur colloid (SC)-radiolabeled eggs. Methods: Liquid egg whites were mixed with 99mTc-SC before cooking in conjunction with the standardized protocol. A second sample set was prepared by adding the 99mTc-SC to eggs after they were cooked. Each sample set was placed in a solution of HCl and pepsin to simulate gestation. Radiolabeling efficacy was tested on each sample set at 2 and 4 h after gestating in HCl and pepsin. Results: 99mTc-SC added to the liquid egg whites before microwave cooking yielded radiolabeling efficacy of 70% 99mTc-SC after 2 and 4 h of simulated gastric fluid gestation. In contrast, radiolabeling after cooking the egg whites yielded 50% radiolabeling after simulated gestation. Conclusion: The results from this experiment showed that the method of mixing the 99mTc-SC with liquid egg whites before microwave cooking has higher binding efficacy than when adding 99mTc-SC onto already cooked egg whites. These results highlight the importance of following the standardized protocol for the meal preparation of a gastric emptying study.

Ectopic colloid goiter in mediastinum with normal thyroid gland.

Ectopic thyroid tissue is a rare developmental abnormality involving aberrant embryogenesis of the thyroid gland during passage from the primitive foregut to the pretracheal position. The most frequent position is the base of the tongue (lingual thyroid); however, it has been described in other sites, such as the submandibular region, trachea, mediastinum, and subdiaphragmatic regions.Here, we report a case of an adenomatous goiter that developed in mediastinal thyroid tissue without any connection to the pretracheal thyroid gland.

Recent advances in understanding the interfacial activity of antioxidants in association colloids in bulk oil.

The chemical stability of edible oils rich in polyunsaturated fatty acids (PUFAs) is a major challenge within the food and supplement industries, as lipid oxidation reduces oil quality and safety. Despite appearing homogeneous to the human eye, bulk oils are actually multiphase heterogeneous systems at the nanoscale level. Association colloids, such as reverse micelles, are spontaneously formed within bulk oils due to the self-assembly of amphiphilic molecules that are present, like phospholipids, free fatty acids, and/or surfactants. In bulk oil, lipid oxidation often occurs at the oil-water interface of these association colloids because this is where different reactants accumulate, such as PUFAs, hydroperoxides, transition metals, and antioxidants. Consequently, the efficiency of antioxidants in bulk oils is governed by their chemical reactivity, but also by their ability to be located close to the site of oxidation. This review describes the impact of minor constituents in bulk oils on the nature of the association colloids formed. And then the formation of mixed reverse micelles (LOOH, (co)surfactants, or antioxidations) during the peroxidation of bulk oils, as well as changes in their composition and structure over time are also discussed. The critical importance of selecting appropriate antioxidants and surfactants for the changes of interface and colloid, as well as the inhibition of lipid oxidation is emphasized. The knowledge presented in this review article may facilitate the design of bulk oil products with improved resistance to oxidation, thereby reducing food waste and improving food quality and safety.

Humic acid-mediated transport of a typical soil passivation remediation product (chloropyromorphite) in saturated porous media.

Conversion of labile Pb species into chloropyromorphite (CPY) using phosphorus-bearing amendments was considered to be an ideal strategy in soil passivation remediation. However, the fate and transport of CPY in the soil are poorly understood. This study aims to fill the knowledge gap by evaluating the fate and transport of CPY under environmentally relevant conditions of humic acid (HA), pH, electrolyte concentration, and species through the saturated sandy medium. Results showed that bare CPY colloids are basically immobile in sandy porous media while the co-existence of HA made the transport of CPY improved by 30%-93.5%. Facilitated transport of CPY was attributed to the increased stability of CPY and the repulsive interaction between CPY particles and sands due to HA adsorption. The mobility of CPY was also increased with increasing pH from 5.0 to 9.0. When the pH was 9 with a 10 mmol/L NaCl background solution, the stronger energy barrier between CPY and sand led to enhanced transport behavior. The divalent Ca2+ had a more dramatic effect than monovalent Na+ on the aggregation and sedimentation of CPY colloids due to its effectivescreening of the surface charge of CPY and bridging interaction with CPY particles. Derjaguin-Landau-Verwey-Overbeek theory and attachment efficiency calculation indicated that high energy barriers were responsible for the high mobility of CPY colloids, while the retention of CPY in sands was mainly caused by secondary energy minimum and physically straining. The findings of this work can help to evaluate the fate of soil passivation remediation products in natural water and soil.

On-chip droplet analysis and cell spheroid screening by capillary wrapping enabled shape-adaptive ferrofluid transporters.

Non-invasive droplet manipulation with no physical damage to the sample is important for the practical value of manipulation tools in multidisciplinary applications from biochemical analysis and diagnostics to cell engineering. It is a challenge to achieve this for most existing photothermal, electric stimuli, and magnetic field-based technologies. Herein, we present a droplet handling toolbox, the ferrofluid transporter, for non-invasive droplet manipulation in an oil environment. It involves the transport of droplets with high robustness and efficiency owing to low interfacial friction. This capability caters to various scenarios including droplets with varying components and solid cargo. Moreover, we fabricated a droplet array by transporter positioning and achieved droplet gating and sorting for complex manipulation in the droplet array. Benefiting from the ease of scale-up and high biocompatibility, the transporter-based droplet array can serve as a digital microfluidic platform for on-chip droplet-based bioanalysis, cell spheroid culture, and downstream drug screening tests.

Metal-oxide precipitation influences microbiome structure in hyporheic zones receiving acid rock drainage.

Streams impacted by historic mining activity are characterized by acidic pH, unique microbial communities, and abundant metal-oxide precipitation, all of which can influence groundwater-surface water exchange. We investigate how metal-oxide precipitates and hyporheic mixing mediate the composition of microbial communities in two streams receiving acid-rock and mine drainage near Silverton, Colorado, USA. A large, neutral pH hyporheic zone facilitated the precipitation of metal particles/colloids in hyporheic porewaters. A small, low pH hyporheic zone, limited by the presence of a low-permeability, iron-oxyhydroxide layer known as ferricrete, led to the formation of steep geochemical gradients and high dissolved-metal concentrations. To determine how these two hyporheic systems influence microbiome composition, we installed well clusters and deployed in situ microcosms in each stream to sample porewaters and sediments for 16S rRNA gene sequencing. Results indicated that distinct hydrogeochemical conditions were present above and below the ferricrete in the low pH system. A positive feedback loop may be present in the low pH stream where microbially mediated precipitation of iron-oxides contributes to additional clogging of hyporheic pore spaces, separating abundant, iron-oxidizing bacteria (Gallionella spp.) above the ferricrete from rare, low-abundance bacteria below the ferricrete. Metal precipitates and colloids that formed in the neutral pH hyporheic zone were associated with a more diverse phylogenetic community of nonmotile, nutrient-cycling bacteria that may be transported through hyporheic pore spaces. In summary, biogeochemical conditions influence, and are influenced by, hyporheic mixing, which mediates the distribution of micro-organisms and, thus, the cycling of metals in streams receiving acid-rock and mine drainage. IMPORTANCE: In streams receiving acid-rock and mine drainage, the abundant precipitation of iron minerals can alter how groundwater and surface water mix along streams (in what is known as the "hyporheic zone") and may shape the distribution of microbial communities. The findings presented here suggest that neutral pH streams with large, well-mixed hyporheic zones may harbor and transport diverse microorganisms attached to particles/colloids through hyporheic pore spaces. In acidic streams where metal oxides clog pore spaces and limit hyporheic exchange, iron-oxidizing bacteria may dominate and phylogenetic diversity becomes low. The abundance of iron-oxidizing bacteria in acid mine drainage streams has the potential to contribute to additional clogging of hyporheic pore spaces and the accumulation of toxic metals in the hyporheic zone. This research highlights the dynamic interplay between hydrology, geochemistry, and microbiology at the groundwater-surface water interface of acid mine drainage streams.

Properties of biochar colloids and behaviors in the soil environment: Influencing the migration of heavy metals.

Biochar pyrolyzed by biomass shows excellent application prospects for heavy metal (HM) remediation, but a part of biochar can be inevitably broken into micro- and nano-sized biochar colloids (BCs) under biological and physicochemical actions in soil. BCs derived in the process of remediation have rough surface, rich elemental species and contents, and multiple functional groups, which are similar to biochar. However, BCs have some unique colloidal properties because of their micro and nano scale size. Due to these properties, BCs exhibit strong mobilities in the soil environment, and the mobilities may be influenced by a combination of colloidal properties of BCs and environmental factors including soil colloids and other soil environmental conditions. In addition, BCs may have affinity effects on HMs through electrostatic adsorption, ion exchange, surface complexation, precipitation/co-precipitation, and redox because of the properties such as large specific surface area, and rich oxygen-containing functional groups and minerals on the surface. This review summarizes the physicochemical and migratory properties of BCs, and the internal and external factors affecting the migration of BCs in the soil environment, and the possible effects of BCs on HMs are high-lighted. This review provides a theoretical basis for the optimization of soil contaminated with HMs after remediation using biochar. Notably, the innovative idea that BCs may influence the presence of HMs in soil needs to be further confirmed by more targeted detection and analysis methods in future studies to prevent the possible environmental toxicities of the lateral and vertical diffusion of HM caused by BCs in soil.

Concordance of vacuum compression molding with spray drying in screening of amorphous solid dispersions of itraconazole.

Spray drying is a well-established method for screening spray dried dispersions (SDDs) but is material consuming, and the amorphous solid dispersions (ASDs) formed have low bulk density. Vacuum Compression Molding (VCM) is a potential method to avoid these limitations. This study focuses on VCM to screen ASDs containing itraconazole and L, M, or H polymer grades of hydroxypropyl methylcellulose acetate succinate (HPMCAS) and compares their morphology, amorphous stability, and dissolution performance with spray drying. Results indicate that VCM ASDs were comparable to SDDs. Both VCM ASDs and spray drying SDDs with HPMCAS-L and HPMCAS-M had improved dissolution profiles, while HPMCAS-H did not. Dynamic light scattering findings agreed with dissolution profiles, indicating that L and M grades produced monodisperse, smaller colloids, whereas H grade formed larger, polydisperse colloids. Capsules containing ASDs from VCM disintegrated and dissolved in the media; however, SDD capsules formed agglomerates and failed to disintegrate completely. Findings indicate that the VCM ASDs are comparable to SDDs in terms of dissolution performance and amorphous stability. VCM may be utilized in early ASD formulation development to select drug-polymer pairs for subsequent development.

Effect of hydrocolloids on starch digestion: A review.

Rapidly digestible starch can increase postprandial blood sugar rapidly, which can be overcome by hydrocolloids. The paper aims to review the effect of hydrocolloids on starch digestion. Hydrocolloids used to reduce starch digestibility are mostly polysaccharides like xanthan gum, pectin, ß-glucan, and konjac glucomannan. Their effectiveness is related to their source and structure, mixing mode of hydrocolloid/starch, physical treatment, and starch processing. The mechanisms of hydrocolloid action include increased system viscosity, inhibition of enzymatic activity, and reduced starch accessibility to enzymes. Reduced starch accessibility to enzymes involves physical barrier and structural orderliness. In the future, physical treatments and intensity used for stabilizing hydrocolloid/starch complex, risks associated with different doses of hydrocolloids, and the development of related clinical trials should be focused on. Besides, investigating the effect of hydrocolloids on starch should be conducted in the context of practical commercial applications rather than limited to the laboratory level.

Xanthan gum and pectin as beverage stabilizers reduce the digestive enzyme hydrolysis of antioxidant and antihypertensive peptides obtained from a brewery byproduct.

An acidic beverage was formulated with xanthan gum (XG), pectin (P) and brewer spent grain (BSG) peptides with antioxidant and antihypertensive properties. The impact of hydrocolloids levels on peptide bioaccessibility was studied. Peptides were obtained from BSG using Purazyme and Flavourzyme enzymes. BSG peptides were fractionated by ultrafiltration (UF) and four fractions were obtained: F1 (>10 kDa), F2 (10-5 kDa), F3 (1-5 kDa), and F4 (<1 kDa). F3 showed the highest protein purity, ferulic acid content, proportion of amphipathic peptides, and bioactive properties (ABTS+ radical scavenging and ACE-I inhibitory activity). The identified peptides from F3 by tandem mass spectrometry were 138. In silico analysis showed that 26 identified peptides had ABTS+ inhibitory activity, while 59 ones presented good antihypertensive properties. The effect of XG and P levels on bioaccessibility of F3 peptides in the formulated beverages was studied by a central composite experimental design. It was observed that F3 peptides interacted with hydrocolloids by electrostatic forces at pH of formulated beverages. The addition of hydrocolloids to formulation modulated the release of the antioxidant peptides and protected the degradation of ACE-I inhibitory peptides from F3 during simulated gastrointestinal digestion. Finally, the level of hydrocolloids that produced intermediate viscosities in the formulated beverages improved the bioaccessibility of the F3 peptides.