Experimental studies of iron transformations kinetics and autocatalysis during its physicochemical removal from underground water

The mathematical model of physicochemical iron removal from groundwater was developed. It consists of three interrelated compartments. The results of the experimental research provide information in support of the first two compartments of the mathematical model. The dependencies for the concentrations of the adsorbed ferrous iron and deposited hydroxide concentrations are obtained as a result of the exact solution of the system of the mass transfer equations for two forms of iron in relation to the inlet surface of the bed. An analysis of the experimental data of the dynamics of the deposit accumulation in a small bed sample was made, using a special application that allowed to select the values of the kinetic coefficients and other model parameters based on these dependencies. We evaluated the autocatalytic effect on the dynamics of iron ferrous and ferric forms. The verification of the mathematical model was carried out involving the experimental data obtained under laboratory and industrial conditions.

Modulation of MagR magnetic properties via iron–sulfur cluster binding

Iron–sulfur clusters are essential cofactors found in all kingdoms of life and play essential roles in fundamental processes, including but not limited to respiration, photosynthesis, and nitrogen fixation. The chemistry of iron–sulfur clusters makes them ideal for sensing various redox environmental signals, while the physics of iron–sulfur clusters and its host proteins have been long overlooked. One such protein, MagR, has been proposed as a putative animal magnetoreceptor. It forms a rod-like complex with cryptochromes (Cry) and possesses intrinsic magnetic moment. However, the magnetism modulation of MagR remains unknown. Here in this study, iron–sulfur cluster binding in MagR has been characterized. Three conserved cysteines of MagR play different roles in iron–sulfur cluster binding. Two forms of iron–sulfur clusters binding have been identified in pigeon MagR and showed different magnetic properties: [3Fe–4S]-MagR appears to be superparamagnetic and has saturation magnetization at 5 K but [2Fe–2S]-MagR is paramagnetic. While at 300 K, [2Fe–2S]-MagR is diamagnetic but [3Fe–4S]-MagR is paramagnetic. Together, the different types of iron–sulfur cluster binding in MagR attribute distinguished magnetic properties, which may provide a fascinating mechanism for animals to modulate the sensitivity in magnetic sensing.

Iron-Coupled Anaerobic Oxidation of Methane in Marine Sediments: A Review

Anaerobic oxidation of methane (AOM) is one of the major processes of oxidizing methane in marine sediments. Up to now, extensive studies about AOM coupled to sulfate reduction have been conducted because SO42− is the most abundant electron acceptor in seawater and shallow marine sediments. However, other terminal electron acceptors of AOM, such as NO3−, NO2−, Mn(IV), Fe(III), are more energetically favorable than SO42−. Iron oxides, part of the major components in deep marine sediments, might play a significant role as an electron acceptor in the AOM process, mainly below the sulfate–methane interface, mediated by physiologically related microorganisms. Iron-coupled AOM is possibly the dominant non-sulfate-dependent AOM process to consume methane in marine ecosystems. In this review, the conditions for iron-coupled AOM are summarized, and the forms of iron oxides as electron acceptors and the microbial mechanisms are discussed.

Mössbauer study of iron gall inks on historical documents

Iron gall ink was used in the Western world as a permanent writing material already in late Roman times and throughout the Middle Ages, until it became obsolete in the twentieth century. There is much interest in experimental methods to determine the state of the ink and its degradation products on historical documents. Mössbauer spectroscopy with 57Fe is such a method, and it has the particular advantage to be sensitive to the chemical bonding of iron, but this method has only rarely been applied to historical documents. In this paper we present Mössbauer data for two damaged documents from a Library in Granada and a handwritten German book from the eighteenth century. In addition to the inked parts of the manuscripts, ink-free parts were studied to determine the amount and chemical state of the iron in the papers. These new results are discussed in the context of previously published Mössbauer data. In one of the investigated documents Fe(II)-oxalate, FeC2O4·2H2O, was observed. The assignment of the various Fe3+ sites in the different documents is rather difficult and often there is a superposition of various species. Known forms of iron gallate are definitely not present on the inked papers. The observed ferric species can be remains of Fe3+ polyphenol complexes of the ink, complexes of Fe3+ with degradation products of the cellulose of the paper or gum arabic, or very small iron oxide or hydroxide nanoparticles.

Safe and effective delivery of supplemental iron to healthy older adults: The double-blind, randomized, placebo-controlled trial protocol of the Safe Iron Study

The forms of iron currently available to correct iron deficiency have adverse effects, including infectious diarrhea, increased susceptibility to malaria, inflammation and detrimental changes to the gut microbiome. These adverse effects limit their use such that the growing burden of iron deficiency has not abated in recent decades. Here, we summarize the protocol of the “Safe Iron Study”, the first clinical study examining the safety and efficacy of novel forms of iron in healthy, iron-replete adults. The Safe Iron Study is a double-blind, randomized, placebo-controlled trial conducted in Boston, MA, USA. This study compares ferrous sulfate heptahydrate (FeSO4·H2O) with two novel forms of iron supplements (iron hydroxide adipate tartrate (IHAT) and organic fungal iron metabolite (Aspiron™ Natural Koji Iron)). In Phase I, we will compare each source of iron administrated at a low dose (60 mg Fe/day). We will also determine the effect of FeSO4 co-administrated with a multiple micronutrient powder and weekly administration of FeSO4. The forms of iron found to produce no adverse effects, or adverse effects no greater than FeSO4 in Phase I, Phase II will evaluate a higher, i.e., a therapeutic dose (120 mg Fe/day). The primary outcomes of this study include ex vivo malaria (Plasmodium falciparum) infectivity of host erythrocytes, ex vivo bacterial proliferation (of selected species) in presence of host plasma and intestinal inflammation assessed by fecal calprotectin. This study will test the hypotheses that the novel forms of iron, administered at equivalent doses to FeSO4, will produce similar increases in iron status in iron-replete subjects, yet lower increases in ex vivo malaria infectivity, ex vivo bacterial proliferation, gut inflammation. Ultimately, this study seeks to contribute to development of safe and effective forms of supplemental iron to address the global burden of iron deficiency and anemia. Registration: ClinicalTrials.gov identifier: NCT03212677; registered: 11 July 2017.

Patient blood management

Background. Blood transfusions (BT) remain one of the most common medical procedures: about 110,000 doses of whole blood are collected annually and almost as many are transfused. Approximately every 10th patient who undergoes invasive procedures in the hospital needs BT. However, 40-60 % of BT in patients without bleeding are inappropriate. Objective. To describe modern views on the BT. Materials and methods. Analysis of the literature on this issue. Results and discussion. The triad of major risk factors for perioperative complications includes three interrelated factors: blood loss, anemia, and BT. The use of blood products is accompanied by an increase in the number of complications (not directly related to BT) and 30-day mortality. Fatal consequences of blood transfusion are also possible. They include acute lung damage associated with BT, hemolytic and bacterial complications, circulatory overload, anaphylaxis. Patient blood management (PBM) includes early detection and treatment of preoperative anemia, especially in patients at high risk of bleeding; minimization of blood loss and maximally blood-saving tactics; rational and guideline-adequate administration of allogenic blood products. About 39 % of patients scheduled for surgery have preoperative anemia. Absolute iron deficiency (ID) is present in 62 % of patients with preoperative anemia. Ferritin level <30 μg/L is an indicator of such anemia. Preoperative anemia is an independent risk factor for mortality and complications, so in presence of anemia, major emergency surgery should be postponed until hemoglobin returns to normal. The target level of the latter in the treatment of preoperative anemia should be 130 g/L for both sexes. If surgery is scheduled 6-8 weeks after the revealing of ID with or without anemia, oral replacement therapy should be performed. Parenteral forms of iron are used if there are <6 weeks left before the planned operation or the hemoglobin level is <100 g/L. If necessary, BT can be performed according to a liberal (BT is prescribed at a hemoglobin level <90-100 g/L) or restrictive (<70-80 g/L) strategy. According to a large-scale meta-analysis, the latter almost halves the risk of erythromass transfusion compared to the former. As recommended by the National Institute for Health and Care Excellence, it is advisable to apply a single-dose strategy with reassessment of BT requirements after each blood transfusion. Decisions in patients with chronic BT-dependent anemia and cancer should be made individually. The use of intravenous iron supplements before surgery can reduce the number of BT in the postoperative period. Sufer (“Yuria-Pharm”) is a trivalent iron for intravenous use, which effectively, quickly and safely increases hemoglobin levels. As it was mentioned, another element of the PBM is the minimization of blood loss. Tranexamic acid preparations (Sangera, “Yuria-Pharm”) can be prescribed for this purpose. Tranexamic acid is a lysine-like inhibitor of fibrinolysis; it is recommended for the prevention of bleeding with expected moderate and severe blood loss (>500 ml). In patients with trauma with massive blood loss or with a high risk of intracranial hemorrhage, it is also advisable to use tranexamic acid. Its activity is 26 times higher than the activity of aminocaproic acid. Tranexamic acid is highly effective; it reduces the need for BT without increasing the risk of thrombosis. Conclusions. 1. The triad of major risk factors for perioperative complications includes three interrelated factors: blood loss, anemia, and BT. 2. PBM includes early detection and treatment of preoperative anemia, minimization of blood loss and adequate administration of allogenic blood products. 3. In conditions of preoperative anemia, it is advisable to correct diabetes with oral or parenteral forms of iron. 4. Tranexamic acid drugs are prescribed to minimize blood loss.

New Perspectives on Iron-Based Nanostructures

Among all minerals, iron is one of the elements identified early by human beings to take advantage of and be used. The role of iron in human life is so great that it made an era in the ages of humanity. Pure iron has a shiny grayish-silver color, but after combining with oxygen and water it can make a colorful set of materials with divergent properties. This diversity sometimes appears ambiguous but provides variety of applications. In fact, iron can come in different forms: zero-valent iron (pure iron), iron oxides, iron hydroxides, and iron oxide hydroxides. By taking these divergent materials into the nano realm, new properties are exhibited, providing us with even more applications. This review deals with iron as a magic element in the nano realm and provides comprehensive data about its structure, properties, synthesis techniques, and applications of various forms of iron-based nanostructures in the science, medicine, and technology sectors.