Impact of ionic composition of groundwater on oxidative iron precipitation

In the Netherlands, approximately 60% of drinking water is obtained from (generally anaerobic) groundwater. This requires aeration followed by rapid sand filtration (RSF) to remove iron, manganese, arsenic and ammonium. The mechanisms responsible for their removal or the clogging of RSFs and breakthrough of colloidal iron or manganese oxides have not been fully elucidated in previous studies. In this work, factors affecting iron precipitation have been studied in an aerated, continuously stirred bench scale jar experiments to simulate the supernatant layer of submerged sand filters. Time series data of filtered iron concentration and precipitate size have been collected in experiments with synthetic groundwater with and without P, Si, HCO3 and Ca at neutral pH. We show that precipitate growth is not influenced by different HCO3 concentrations but is reduced drastically when NOM is present and, to lesser extent, Si as well. The addition of P appears to hamper precipitate growth to some extent, but requires more research. We also observe that addition of Ca improves the growth of Fe precipitates in the presence of Si and especially NOM. These results have great significance for improving Fe removal efficiency of groundwater treatment plants in Netherlands and abroad.

Macular corneal dystrophy related to novel mutations of CHST6 in a Chinese family and clinical observation after penetrating keratoplasty

Background Macular corneal dystrophy (MCD) is a rare corneal stromal dystrophy with bilateral progressive vision loss. The pathogenic gene of MCD is carbohydrate sulfotransferase 6 (CHST6). Herein, we report a novel missense mutation and a rare exon deletion mutation in the CHST6 gene in a Chinese family with MCD. Methods Genomic DNA was extracted from the peripheral blood, and next generation sequencing was used to analyse the gene sequence. The pathogenic mutations were identified in all affected family members. The proband successively received binocular penetrating keratoplasty (PKP), and the corneas were examined by histopathology and colloidal iron staining to prove the diagnosis. A long-term follow-up was made to observe the changes after PKP. Results Genetic analysis demonstrated hemizygous mutations in the proband, including a novel c.520A>C (p.K174Q) missense mutation and a rarely reported exon 3 deletion mutation, which were co-segregated with the MCD phenotypes in the pedigree. The positive colloidal iron staining confirmed the diagnosis of MCD in the proband. However, the clinical phenotype and pathological manifestation of both eyes were different from each other because of complicated keratitis in the left eye. During the nine years of follow-up, visual acuity was improved significantly, and the cornea was transparent without rejection and postoperative recurrence in both eyes. Conclusions The novel hemizygous mutations were thought to contribute to the loss of CHST6 function, which induced typical clinical and pathological features of MCD. PKP was an effective treatment for MCD.

Phytate Exudation by the Roots of Pteris Vittata Can Dissolve Colloidal Fepo4

Phosphorus (P) is limiting nutrient in soil system. The P availability in soil strongly depend on Iron (Fe) speciation. Colloidal iron phosphate (FePO4coll) is an important phosphorus (P) fraction in soil solution that carry P from soil to water bodies. This study tested the hypothesis that phytate exudation by Pteris vittata (P. vittata) can dissolve FePO4coll that leads to release of P and Fe. The phytate exudation in P. vittata increased from 434−2136 mg kg−1 as the FePO4coll concentration increased from 0−300 mM. The total P in P. vittata tissue increased from 2.88 to 8.28 g kg−1, the trichloroacetic acid P fractions (TCA fractions) were: inorganic P (0.86–5.10 mg g−1), soluble organic P (0.25–0.87 mg g−1), and insoluble organic P (0.16–2.03 mg g−1) which leads to higher biomass as FePO4coll increased from 0−300 mM. The linear regression analysis showed that FePO4 solubilizing activity has a positive correlation with TP, TCA P fractions in P. vittata, TP in growth media, and root exudates. This study shows that phytate exudation dissolved the FePO4coll due to the chelation effect of phytic acid on Fe, and due to the high Fe–P solubilizing activity in root exudates of P. vittata.

Low-grade oncocytic tumour expands the spectrum of renal oncocytic tumours and deserves separate classification: a review of 23 cases from a single tertiary institute

AimsLow-grade oncocytic tumour (LOT) has recently been introduced as a potential distinct entity.MethodsAt the Indiana University department of pathology, primary renal epithelial neoplasms between 2005 and 2020 were searched after appropriate institutional review board permissions.ResultsTwenty-three cases (male/female ratio 14/9) with a median age of 66 (23–84 years) were identified. The majority of patients underwent partial nephrectomy (15/23, 65%), with a median tumour size of 4.0 cm (2.2–10.5 cm). Only one case had infiltration beyond the kidney (perinephric fat). Solid/diffuse proliferation of tightly packed oncocytic tumour cells and occasional tubule formations, with an abrupt edematous change in the stroma with loosely connected small clusters of tumour cells. Along with diffuse CK7 expression with lack of CD117 in all cases, vimentin was positive in 8/23 cases (35%, 5 focal). CD10 was expressed in 6/13 (46%, 4 focal). Alpha-Methylacyl-CoA Racemase (AMACR) was positive in 5/8 (63%) cases. Focal but intense cytoplasmic colloidal iron stain was present in 3/20 (15%) cases. Luminal or cytoplasmic/perinuclear precipitation was observed in 8/20 (40%) cases. Succinate Dehydrogenase B (SDHB) was performed in 6 cases, with all retained expression.ConclusionsLOT is a clinically indolent and potentially benign entity with distinguishable morphology and immunohistochemical profile that can be performed and be easily interpreted in most of surgical pathology settings. Additional studies with larger cohorts, comprehensive molecular evaluation and longer follow-up are needed to definitively recognise these tumours as a separate entity and to further address the possibility of active surveillance options in eligible patients.

Impact of Tuning the Surface Charge Distribution on Colloidal Iron Oxide Nanoparticle Toxicity Investigated in Caenorhabditis elegans

Assessing the toxic effect in living organisms remains a major issue for the development of safe nanomedicines and exposure of researchers involved in the synthesis, handling and manipulation of nanoparticles. In this study, we demonstrate that Caenorhabditis elegans could represent an in vivo model alternative to superior mammalians for the collection of several physiological functionality parameters associated to both short-term and long-term effects of colloidally stable nanoparticles even in absence of microbial feeding, usually reported to be necessary to ensure appropriate intake. Contextually, we investigated the impact of surface charge on toxicity of superparamagnetic iron oxide coated with a wrapping polymeric envelop that confers them optimal colloidal stability. By finely tuning the functional group composition of this shallow polymer–obtaining totally anionic, partially pegylated, partially anionic and partially cationic, respectively–we showed that the ideal surface charge organization to optimize safety of colloidal nanoparticles is the one containing both cationic and anionic groups. Our results are in accordance with previous evidence that zwitterionic nanoparticles allow long circulation, favorable distribution in the tumor area and optimal tumor penetration and thus support the hypothesis that zwitterionic iron oxide nanoparticles could be an excellent solution for diagnostic imaging and therapeutic applications in nanooncology.

The Role of Macrophytes in Constructed Surface-flow Wetlands for Mine Water Treatment: A Review

Constructed wetlands are a standard sustainable technology in waste and mine water treatment. Whereas macrophytes actively contribute to decomposition and/or removal of wastewater’s organic pollutants, removal of hydrolysable metals from mine water is not attributable to direct metabolic, but rather various indirect macrophyte-related mechanisms. These mechanisms result in higher treatment efficiency of (vegetated) wetlands relative to (unvegetated) settling ponds. Contribution of macrophytes to treatment predominantly includes: enhanced biogeochemical oxidation and precipitation of hydrolysable metals due to catalytic reactions and bacterial activity, particularly on immersed macrophyte surfaces; physical filtration of suspended hydrous ferric oxides by dense wetland vegetation down to colloids that are unlikely to gravitationally settle efficiently; scavenging and heteroaggregation of dissolved and colloidal iron, respectively, by plant-derived natural organic matter; and improved hydrodynamics and hydraulic efficiency, considerably augmenting retention and exposure time. The review shows that constructed surface-flow wetlands have considerable advantages that are often underestimated. In addition to treatment enhancement, there are socio-environmental benefits such as aesthetic appearance, biotope/habitat value, and landscape diversity that need to be considered. However, there is currently no quantitative, transferrable approach to adequately describe the effect and magnitude of macrophyte-related benefits on mine water amelioration, let alone clearly assign optimal operational deployment of either settling ponds or wetlands. A better (quantitative) understanding of underlying processes and kinetics is needed to optimise assembly and sizing of settling ponds and wetlands in composite passive mine water treatment systems.

Relative importance of organic- and iron-based colloids in six Nova Scotian lakes

Dissolved organic matter (DOM) concentrations have been increasing in parts of the northern hemisphere for several decades. This process—brownification—often accompanies increasing iron and aluminum, but the metal–DOM interactions these concurrent trends imply are poorly described. Here we used field-flow fractionation with UV and ICP-MS detection to measure the size distribution of colloidal iron, aluminum, manganese, copper, uranium, and chromophoric DOM in six lakes over six months. Five of these lakes have browned to some degree in the past three decades, with linear increases in organic carbon and color ranging from 0.01 to 0.13 mg C L−1 yr−1 and 0.13–1.94 PtCo yr−1. Browning trends were more pronounced and colloids more abundant in lakes with wetlands in their catchments. Iron and aluminum were present in two primary fractions, sized nominally at 1 and 1000 kDa. The 1 kDa fraction included the primary DOM signal, while the 1000 kDa fraction absorbed minimally at 254 nm and likely represents iron-rich (oxyhydr)oxides. Colloidal manganese was sized at 1000+ kDa, whereas colloidal copper and uranium occurred primarily at 1 kDa. These associations fit with a pattern of increasing DOC, iron, aluminum, and color in the region’s lakes. They represent a significant challenge for drinking water treatment systems, especially those in remote communities. Given that browning trends are expected to continue, monitoring plans would better inform treatment process design and operation by characterizing DOM and iron-rich, primarily inorganic colloids that contribute to adverse water quality outcomes.

Comparison between oral ferrous ascorbate and colloidal iron in the treatment of iron deficiency anemia

Background: Anemia is a global health issue. There is association of impaired cognition and iron deficiency anemia. Ferrous and ferric forms of oral iron preparations are available for the treatment of iron deficiency anemia. This study was conducted with an aim to compare the efficacy and safety of oral ferrous ascorbate and colloidal iron in the treatment of iron deficiency anemia.Methods: It was a prospective interventional study with 12 weeks of treatment protocols alternatively assigned to children diagnosed with iron deficiency anemia. Patients received either of two iron preparation used in study and they were assessed at week 0, 4, 8 and 12.Results: Hemoglobin (gm%) significantly increased from 7.40 to 12.87 in ferrous ascorbate group and from 7.24 to 11.32 in colloidal iron group at the end of 12 weeks of treatment (p<0.05). There was significant increase in corrected reticulocyte count (%) from 0.52 to 1.39 in ferrous ascorbate group and from 0.42 to 1.27 in colloidal iron group (p<0.05). Serum ferritin (mcg/liter) was also significantly increased from 11.54 to 21.53 in ferrous ascorbate group and from 10.57 to 20.52 in colloidal iron group at the end of 12 weeks (p<0.05).Conclusions: The present study concluded that the ferrous ascorbate is an efficient oral iron supplement in the treatment of iron deficiency anemia in the pediatric age group compared to colloidal iron.

Colloidal Iron Oxide Formulation for Equine Hoof Disinfection

The presence of bacteria of various origins on horse hoofs enables the onset of infections following trauma or even post-surgical wounds. Thus, the analysis of new antibacterial substances is of fundamental importance. In this study, the antibacterial efficacy of Iron Animals (IA), a stable colloidal suspension of iron oxide, organic acids, and detergents, was tested in vitro and in vivo. In vitro assays were performed to test the unspecific inhibitory effect of IA on both gram-positive and gram-negative bacteria monitoring the microorganism growth by spectrophotometry (optical density OD600) at 37 °C for 24 h. In vivo test consists on the quantification of the bacterial load in colony forming units per gram (CFU/g) of specimens collected from the frog region of the anterior hooves of 11 horses. Sampling followed the application of four disinfectant protocols consisting of two consecutive 3 min scrubs with 50 mL of 10% Povidone-iodine (PI) or 4% Chlorhexidine (CHx), with or without an additional application for 15 min of 10 mL of Iron Animals (PI+IA and CHx+IA). In vitro, IA completely suppressed the bacterial growth of all the tested microorganisms, resulting in effectiveness also against CHx-resistant bacteria, such as Staphylococcus aureus. In vivo, PI emerged as an ineffective protocol; CHx was effective in 18% of cases, but with the addition of IA (CHx + IA) its use emerged as the best disinfectant protocol for horse hoof, achieving the lowest bacterial load in 55% of cases. The addition of IA, after PI or CHx, improves the effectiveness of both disinfectants leading to the highest bactericidal activity in 82% of cases.

Nasal Polyposis in mucopolysaccharidosis type II

Mucopolysaccharidosis (MPS) type II is a rare multisystem disorder resulting from the accumulation of breakdown products of glycosaminoglycans in the body tissues. Many patients with this disease undergo ENT (ear, nose and throat) surgeries such as adenotonsillectomy and tympanocentesis at a very early age, much before the diagnosis of MPS. Nasal polyposis is a rare occurrence, with only one case of MPS II with polyposis reported in the literature. We present a patient who presented with recurrent nasal polyposis from the age of 2 years. Hale’s colloidal iron was used to stain these ‘nasal polyps’, which revealed that they are, in fact, mucopolysaccharide-laden sinonasal mucosa prolapsing into the nasal cavities. We believe this is the first time that this stain has been used to stain nasal polyps in MPS. In addition to the histopathological peculiarities of these nasal masses, we also discuss the natural history of nasal polyposis in MPS II.