Single-Micelle-Templated Synthesis of Hollow Barium Carbonate Nanoparticle for Drug Delivery.

A laboratory-synthesized triblock copolymer poly(ethylene oxide-b-acrylic acid-b-styrene) (PEG-PAA-PS) was used as a template to synthesize hollow BaCO3 nanoparticles (BC-NPs). The triblock copolymer was synthesized using reversible addition-fragmentation chain transfer radical polymerization. The triblock copolymer has a molecular weight of 1.88 × 104 g/mol. Transmission electron microscopy measurements confirm the formation of spherical micelles with a PEG corona, PAA shell, and PS core in an aqueous solution. Furthermore, the dynamic light scattering experiment revealed the electrostatic interaction of Ba2+ ions with an anionic poly(acrylic acid) block of the micelles. The controlled precipitation of BaCO3 around spherical polymeric micelles followed by calcination allows for the synthesis of hollow BC-NPs with cavity diameters of 15 nm and a shell thickness of 5 nm. The encapsulation and release of methotrexate from hollow BC-NPs at pH 7.4 was studied. The cell viability experiments indicate the possibility of BC-NPs maintaining biocompatibility for a prolonged time.

[A case of arrhythmia caused by barium carbonate poisoning].

Barium carbonate poisoning is mostly caused by mistaken ingestion in clinical cases, and self-administration of poisoning is rare. In November 2020, Tianjin Occupational Disease Prevention Hospital admitted a patient with severe hypokalemia complicated with arrhythmia after taking poison. It is very important to take timely and effective potassium supplementation, symptomatic and detoxification treatment in the course of treatment. At the same time, closely observing the changes of vital signs and taking quick and accurate rescue measures in the event of malignant arrhythmia are the keys to ensuring the success of rescue. In this paper, the clinical data of the case were retrospectively analyzed, providing reference for the diagnosis and treatment of similar clinical cases.

Insulin-Loaded Barium Salt Particles Facilitate Oral Delivery of Insulin in Diabetic Rats.

Oral delivery is considered as the most preferred and yet most challenging mode of drug administration; especially a fragile and sensitive peptide like insulin that shows extremely low bioavailability through the gastro-intestinal (GIT) route. To address this problem, we have designed a novel drug delivery system (DDS) using precipitation-induced Barium (Ba) salt particles. The DDS can load insulin molecules and transport them through the GIT route. There were several in vitro simulation tests carried out to prove the efficiency of Ba salt particles as oral delivery candidates. All three Ba salt particles (BaSO4, BaSO3, and BaCO3) showed very good loading of insulin (>70% in all formulations) and a degree of resistance throughout a wide range of pHs from basic to acidic conditions when assessed by spectrophotometry. Particles and insulin-associated particles were morphologically assessed and characterized using FE-SEM and FT-IR. A set of tests were designed and carried out with mucin to predict whether the particles are potentially capable of overcoming one of the barriers for crossing intestinal epithelium. The mucin binding experiment demonstrated 60-100% of mucin adhesion to the three different particles. FT-IR identifies the characteristic peaks for mucin protein, particles, and particle-mucin complex re-confirming mucin adhesion to the particles. Finally, the effectiveness of nano-insulin was tested on streptozotocin (STZ) induced diabetic rats. A short acting human insulin analog, insulin aspart, was loaded into Ba salt particles at a dose of 100 IU/Kg prior to oral administration. Among the three formulations, insulin aspart-loaded BaSO4 and BaCO3 particles dramatically reduced the existing hyperglycemia. BaSO4 with loaded Insulin showed an onset of glucose-lowering action within 1 hr, with blood glucose level measured significantly lower compared to the 2nd and 3rd h (p < 0.05). Insulin-loaded BaCO3 particles showed a significant decrease in blood glucose level at 1-2 h, although the glucose level started to show a slight rise at 3rd h and by 4th h, it was back to baseline level. However, although BaSO3 particles with loaded insulin showed a trend of reduction in blood glucose level, the reduction was not found to be significant (p < 0.05) at any point in time. Therefore, oral formulations of insulin/BaSO4 and insulin/BaCO3 particles were observed as effective as native insulin aspart subcutaneous formulation in terms of onset and duration of action. Further investigation will be needed to reveal bioavailability and mechanism of action of this novel Nano-Insulin formulations.

Barium isotope fractionation during the experimental transformation of aragonite to witherite and of gypsum to barite, and the effect of ion (de)solvation.

In this study, we present the experimental results for stable barium (Ba) isotope fractionation (137Ba/134Ba) during the transformation of aragonite (CaCO3) and gypsum (CaSO4·2H2O) in Ba-bearing aqueous solution to witherite (BaCO3) and barite (BaSO4), respectively. The process was studied at three temperatures between 4 and 60 °C. In all cases, the transformation leads to a relative enrichment of the lighter 134Ba isotope in the solid compared to the aqueous solution, with 137/134Ba enrichment factors between -0.11 and -0.17 ‰ for BaCO3, and -0.21 and -0.26 ‰ for BaSO4. The corresponding mass-dependent 138/134Ba enrichment factors are -0.15 to -0.23 ‰ for BaCO3, and -0.28 to -0.35 ‰ for BaSO4. The magnitude of isotope fractionation is within the range of recent reports for witherite and barite formation, as well as trace Ba incorporation into orthorhombic aragonite, and no substantial impact of temperature can be found between 4 and 80 °C. In previous studies, ion (de)solvation has been suggested to impact both the crystallization process of Ba-bearing solids and associated Ba isotope fractionation. Precipitation experiments of BaSO4 and BaCO3 using an methanol-containing aqueous solution indicate only a minor effect of ion and crystal surface (de)solvation on the overall Ba isotope fractionation process.

Multi-Step Crystallization of Barium Carbonate: Rapid Interconversion of Amorphous and Crystalline Precursors.

The direct observation of amorphous barium carbonate (ABC), which transforms into a previously unknown barium carbonate hydrate (herewith named gortatowskite) within a few hundred milliseconds of formation, is described. In situ X-ray scattering, cryo-, and low-dose electron microscopy were used to capture the transformation of nanoparticulate ABC into gortatowskite crystals, highly anisotropic sheets that are up to 1 µm in width, yet only about 10 nm in thickness. Recrystallization of gortatowskite to witherite starts within 30 seconds. We describe a bulk synthesis and report a first assessment of the composition, vibrational spectra, and structure of gortatowskite. Our findings indicate that transient amorphous and crystalline precursors can play a role in aqueous precipitation pathways that may often be overlooked owing to their extremely short lifetimes and small dimensions. However, such transient precursors may be integral to the formation of more stable phases.

Hematological, biochemical, and histopathological impacts of barium chloride and barium carbonate accumulation in soft tissues of male Sprague-Dawley rats.

The present study was designed to investigate the hematotoxicity, sero-biochemical and histological changes due to the accumulation of BaCl2 and BaCO3, the most important barium salts in our daily lives, in different soft tissues including the liver, kidney, heart, and spleen of adult rats after an oral exposure for 30 consecutive days, and to explain the different mechanisms by which this metal can exert these impacts. For this purpose, adult male rats were divided into three main groups of 15 animals each: group I, serving as controls, group II, receiving BaCl2 orally in a dose of 179 mg barium/kg b.wt, and group III, receiving BaCO3 orally in a dose of 418 mg barium/kg b.wt. for 30 consecutive days. Obviously, normocytic normochromic anemia was evident in both barium groups. Serum biochemical analysis revealed significant declines in glutathione peroxidase, catalase, superoxide dismutase, and urea with significant elevations in malondialdehyde, lactate dehydrogenase, and creatine kinase levels. Hyperphosphatemia, hypokalemia, hypocalcemia, and hypochloremia were also evident in both barium groups. Besides, residual analysis of both barium salts in different body organs revealed significantly abundant barium residues in the liver, spleen, heart, and kidney, respectively in both barium salts groups. Moreover, splenic tissue showed hemosiderosis, peritubular congestion, and necrotic glomeruli with intratubular hemorrhage. Sever subepicardial congestion with intramuscular edema was evident in the heart. In conclusion, BaCl2 and BaCO3 were able to deliver mortalities, antioxidant enzymes exhaustion, and a sort of normocytic normochromic anemia, as well as marked disturbances in cardiac, hepatic, and renal functions due to the accumulation of these two salts in the soft tissues. Therefore, these results demonstrate the unrecognized toxicity of those two barium salts due to their accumulation in various soft tissues of the body and so, this needs to reconsider about barium exposure.

ACBC to Balcite: Bioinspired Synthesis of a Highly Substituted High-Temperature Phase from an Amorphous Precursor.

Energy-efficient synthesis of materials locked in compositional and structural states far from equilibrium remains a challenging goal, yet biomineralizing organisms routinely assemble such materials with sophisticated designs and advanced functional properties, often using amorphous precursors. However, incorporation of organics limits the useful temperature range of these materials. Herein, the bioinspired synthesis of a highly supersaturated calcite (Ca0.5 Ba0.5 CO3 ) called balcite is reported, at mild conditions and using an amorphous calcium-barium carbonate (ACBC) (Ca1-x Ba x CO3 ·1.2H2 O) precursor. Balcite not only contains 50 times more barium than the solubility limit in calcite but also displays the rotational disorder on carbonate sites that is typical for high-temperature calcite. It is significantly harder (30%) and less stiff than calcite, and retains these properties after heating to elevated temperatures. Analysis of balcite local order suggests that it may require the formation of the ACBC precursor and could therefore be an example of nonclassical nucleation. These findings demonstrate that amorphous precursor pathways are powerfully enabling and provide unprecedented access to materials far from equilibrium, including high-temperature modifications by room-temperature synthesis.

Simultaneous structure and luminescence property control of barium carbonate nanocrystals through small amount of lanthanide doping.

Rare earth doping has been widely applied in many functional nanomaterials with desirable properties and functions, which would have a significant effect on the growth process of the materials. However, the controlling strategy is limited into high concentration of lanthanide doping, which produces concentration quenching of the lanthanide ion luminescence with an increase in the Ln3+ concentration, resulting in lowering the fluorescence quantum yield of lanthanide ion. Herein, for the first time, we demonstrate simultaneous control of the structures and luminescence properties of BaCO3 nanocrystals via a small amount of Tb3+ doping strategy. In fact, Tb3+ would partially occupy Ba2+ sites, resulting in the changes to the structures of the BaCO3 nanocrystals, which is primarily determined by charge modulation, including the contributions from the surfaces of crystal nuclei and building blocks. These structurally modified nanocrystals exhibit tunable luminescence properties, thus emerging as potential candidates for photonic devices such as light-emitting diodes and color displays.

Experimental techniques for the growth and characterization of silica biomorphs and silica gardens.

Silica biomorphs and silica gardens are canonical examples of precipitation phenomena yielding self-assembled nanocrystalline composite materials with outstanding properties in terms of morphology and texture. Both types of structures form spontaneously in alkaline environments and rely on simple, and essentially similar, chemistry. However, the underlying growth processes are very sensitive to a range of experimental parameters, distinct preparation procedures, and external conditions. In this chapter, we report detailed protocols for the synthesis of these extraordinary biomimetic materials and identify critical aspects as well as advantages and disadvantages of different approaches. Furthermore, modifications of established standard procedures are reviewed and discussed with respect to their benefit for the control over morphogenesis and the reproducibility of the experiments in both cases. Finally, we describe currently used techniques for the characterization of these fascinating structures and devise promising ways to analyze their growth behavior and formation mechanisms in situ and as a function of time.

Mono- and bimetallic Rh and Pt NSR-catalysts prepared by controlled deposition of noble metals on support or storage component.

Mono- and bimetallic Rh and Pt based NOx storage-reduction (NSR) catalysts, where the noble metals were deposited on the Al2O3 support or BaCO3 storage component, have been prepared using a twin flame spray pyrolysis setup. The catalysts were characterized by nitrogen adsorption, CO chemisorption combined with diffuse reflectance infrared Fourier transform spectroscopy, X-ray diffraction, and scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy. The NSR performance of the catalysts was investigated by fuel lean/rich cycling in the absence and presence of SO2 (25 ppm) as well as after H2 desulfation at 750 °C. The performance increased when Rh was located on BaCO3 enabling good catalyst regeneration during the fuel rich phase. Best performance was observed for bimetallic catalysts where the noble metals were separated, with Pt on Al2O3 and Rh on BaCO3. The Rh-containing catalysts generally showed much higher tolerance to SO2 during fuel rich conditions and lost only little activity during thermal aging at 750 °C.

Hypokalemia due to barium carbonate intoxication / 대한내과학회지

Barium carbonate is commonly used rodenticidally and industrially, but intoxication has been uncommonly reported. Muscle weakness and hypokalemia are the characteristic features of barium carbonate intoxication. Barium-induced hypokalemia is due to a rapid and large transfer of potassium from the extracellular space into the intracellular space resulting from blocking potassium channels by barium ions. We report 35 cases of barium carbonate intoxication which developed after accidental ingestion of barium poisoned noodle. All patients developed severe hypokalemic paralysis and some degree of vomiting and diarrhea. We managed these patients with aggressive potassium supplementation and all patients were discharged without any sequelae.