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Cytotoxicity and cellular uptake of spherical barium sulphate microparticles (diameter 1 µm) were studied with three different cell lines, i.e. THP-1 cells (monocytes; model for a phagocytosing cell line), HeLa cells (epithelial cells; model for a non-phagocytosing cell line), and human mesenchymal stem cells (hMSCs; model for non-phagocytosing primary cells). Barium sulphate is a chemically and biologically inert solid which allows to distinguish two different processes, e.g. the particle uptake and potential adverse biological reactions. Barium sulphate microparticles were surface-coated by carboxymethylcellulose (CMC) which gave the particles a negative charge. Fluorescence was added by conjugating 6-aminofluorescein to CMC. The cytotoxicity of these microparticles was studied by the MTT test and a live/dead assay. The uptake was visualized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The particle uptake mechanism was quantified by flow cytometry with different endocytosis inhibitors in THP-1 and HeLa cells. The microparticles were easily taken up by all cell types, mostly by phagocytosis and micropinocytosis, within a few hours. The interaction of particles and cells is of primary importance in nanomedicine, drug delivery, and nanotoxicology. It is commonly assumed that cells take up only nanoparticles unless they are able to phagocytosis. Here, we demonstrate with chemically and biologically inert microparticles of barium sulphate that even non-phagocytosing cells like HeLa and hMSCs take up microparticles to a considerable degree. This has considerable implication in biomaterials science, e.g. in case of abrasive debris and particulate degradation products from implants like endoprostheses. [Display omitted] [ABSTRACT FROM AUTHOR]

The authors modified BaSO 4 powders with SiO 2 nanoparticles and studied the effect of this modification on powders' structure and optical properties, as well as on the changes of the latter after 5 keV proton irradiation. No significant post-modification changes in structure have been observed. In the IR-spectrum, the authors have recorded the band intensity changes for SiO 2 , Si – O – Si, and Si–Si vibrations, as well as emerging OH group vibration band. Additionally, the authors have noted the appearance of an absorption band in the UV/vis spectra caused by intrinsic point defects in BaSO 4 anionic sublattice. The energy losses induced by displacement and ionization were calculated, as were the proton free paths in the modified powder. It is shown that an increase of radiation stability is provided by solely 1.2% of the proton energy flux absorbed in the nSiO 2 nanolayer contributing to the total energy loss in the entire modified powder. Two mechanisms are proposed for the processes occurring in the nSiO 2 /mBaSO 4 system that determine the increase of its radiation stability compared with the non-modified powder. [ABSTRACT FROM AUTHOR]

Automotive brake friction composites based on several combinations of barium sulphate and cement by-pass dust (CBPD) were manufactured and tribo behaviour is examined as per European regulations on a Krauss machine. The friction coefficient increased upon increasing the amount of CBPD from 0 to 30 wt% and then decreased above 30 wt% CBPD and below 20 wt% barium sulphate contents. Conversely, friction fluctuations and wear increased with decreasing barium sulphate and increasing CBPD contents. In particular, 20 wt% barium sulphate and 30 wt% CBPD filled composites showed the highest friction performance of 0.361, moderate friction stability of 0.76, highest recovery performance of 123.27%, and lowest friction variability of 0.60, whereas the composite with 50 wt% CBPD showed the highest fade resistance of 15.36%. The friction and wear analysis revealed that the fade and recovery response decide the overall frictional performance, whereas material integrity and fade response were the significant determinants of wear performance. The composites' worn surfaces were examined to investigate the associated wear mechanism at the braking interface. [ABSTRACT FROM AUTHOR]

The co-precipitation of radium (Ra) with minerals is prevalent in high-salinity environmental systems, with significant implications for geochemical cycling and radiation risk management. This study extensively investigated Ra co-precipitation through both indoor lake experiments and field investigations of saline lakes. 1) In the indoor experiments, calcium ions (Ca2+) concentration remained stable under high-salinity conditions, while barium ions (Ba2+) showed a marked and continuous decline. Ra is less likely to co-precipitate with Ca minerals but has a higher tendency to co-precipitate with Ba sulfates. However, field investigations provided limited support for co-precipitation based on water chemistry. Variations in Ca2+ and Ba2+ with total dissolved solids (TDS) in saline lakes showed no significant correlation, and both calcite and Ba sulfates may precipitate from solution. Thus, water chemistry profiles can provide an initial assessment of potential co-precipitation occurrences. 2) Our study revealed the responses of four Ra species in high-salinity solutions. Within the selected salinity range, the activity of long-lived Ra significantly decreased, and the calculated precipitation rates indicated their co-precipitation with minerals. Although the co-precipitation signals of short-lived Ra may be obscured by desorption and rapid decay, reasonable calculations confirm that they also underwent co-precipitation. The co-precipitation of all Ra species may be attributed to the compression of the anti-ionic diffusion layer around particles under high-salinity conditions. The molar ratio of Ra to Ba in Ba sulfates is significantly higher than that in gypsum and calcite (Ra/Ca), indicating the probably dominant role of Ba sulfates in co-precipitation. Additionally, variations in Ra/Ba ratios and concentrations of Ba and SO₄2− across these systems further elucidate the control exerted by Ba sulfates on Ra co-precipitation. 3) Previous studies have focused primarily on Ra co-precipitation mechanisms in groundwater and controlled experimental systems, while research on other high-salinity environments, such as saline lakes, remains limited. Findings from our saline lake systems further confirm the prevalence of Ra co-precipitation and provide important insights for other high-salinity natural systems (e.g., the Dead Sea) and polluted environments (e.g., mining sites) where Ra co-precipitation constraints may differ from those in saline lakes. In saline lake systems, salinity/TDS regulate mineral saturation indices (SI) by modulating Ra desorption and SO₄2− levels, thereby controlling (Ra, Ba)SO₄ formation, while the effects of pH and temperature are relatively minor. A limitation of this study is the lack of investigation into the influence of fine colloids and potential complexes on Ra species, a discussion that could offer preliminary insights into Ra transport and applications in other high-salinity systems. [Display omitted] • Ra co-precipitation exists in indoor experiments and field investigations. • Ra co-precipitation phenomenon in lake system has been confirmed. • Ra is likely to co-precipitation with Ba sulfates in saline lakes. • Occurrence of Ra co-precipitation is characterized by environmental heterogeneity. • TDS mobilizes Ra, SO₄2− and SI, promoting (Ra, Ba)SO₄ formation in saline lakes. [ABSTRACT FROM AUTHOR]

• The stability changes of BaSO 4 can be proved by the variations in elastic modulus observed in molecular simulations. • KOH is more readily soluble in dissolving BaSO 4 than NaOH, which is proven by both simulation and experimental processes. • The impact of K+ on BaSO 4 is more evident due to the stronger adsorption effect between potassium ions and sulfate ions. The dissolution of barium sulfate is notably influenced by the structural stability imparted by ionic doping. In this study, we have meticulously calculated three pivotal parameters—bulk modulus, shear modulus, and Young's modulus—through molecular simulations. These calculations have unveiled a robust adsorption interaction between potassium (K+) ions and sulfate ions. Characterized by diminished kinetic energy, reduced electrostatic potential, and an elevated rate of electron transfer, this interaction culminates in the formation of a stable chemical bond. The observed stability is likely due to the comparable radii of potassium and barium ions, facilitating a more intimate chemical linkage with sulfate ions, thereby bolstering the adsorption stability. Furthermore, the experimental data corroborate that the presence of potassium ions augments the solubility of barium sulfate, particularly in alkaline conditions where the pH exceeds 11. Consequently, employing a potassium hydroxide (KOH) solution as the dissolution medium emerges as a strategic and efficacious option. This approach not only enhances the dissolution efficiency of barium sulfate but also contributes to a reduction in operational expenses. [ABSTRACT FROM AUTHOR]

Quantum dots of AgInS 2 and AgInS 2 doped with ZnS were embedded in microscale spherical BaSO 4 and CaCO 3 matrices by co-precipitation approach. Energy dispersive X-ray analysis (EDX) confirmed the homogeneous distribution of quantum dots within the matrices. The effect of encapsulation on the optical properties of quantum dots (QDs) and the dependence of photoluminescence (PL) spectra on temperature were investigated. The similar appearance of the spectra and the same position of the emission maximum for the composites with BaSO 4 and CaCO 3 indicate that the nature of the matrix does not significantly affect the spectral characteristics of quantum dots. While the application of composites based on CaCO 3 at high temperatures is limited due to the degradation, composites with BaSO 4 demonstrate high stability and thermal sensitivity (1.89 ± 0.0012 %/K). Therefore, the composites we studied are well-suited for light conversion and optical temperature sensing applications. [Display omitted] • The temperature sensitivity and optical properties of AgInS 2 embedded in ionic salt crystals have been investigated. [ABSTRACT FROM AUTHOR]

Various noninvasive imaging modalities, including X-ray and computed tomography (CT) imaging, have provided significant advantages in accurately assessing the conditions of the gastrointestinal (GI) tract. The corresponding contrast agent with high resolution and biosafety is one of the most crucial focuses in the diagnosis of GI diseases. In this study, considering the requirements of good biocompatibility and biosafety, a novel imaging platform composed of the high-performance contrast agent based on macrophage membrane-coated BiOI nanodots (BiOI@M) was designed via a facile approach. The BiOI@M exhibited outstanding long-term stability and low toxicity. Significantly, BiOI@M demonstrated superior imaging ability compared to clinical barium sulfate. Higher CT values of BiOI@M were observed at equivalent concentrations to barium sulfate, thereby clearly outlining the stomach, small intestine, caecum, and colon after the oral administration of BiOI@M solutions in X-ray and CT imaging. Taken together, BiOI@M could serve as a novel efficient contrast agent in X-ray/CT imaging of the GI tract and diagnosis of GI diseases. [Display omitted] • A novel GI tract contrast (BiOI@M) for X-ray and CT dual-modal imaging was developed. • BiOI@M was a high-performance contrast agent with great X-ray absorption capability. • BiOI@M clearly delineated the profiles of the GI tract following oral administration. • BiOI@M showed long-term stability, low toxicity and neglectable hemolysis. [ABSTRACT FROM AUTHOR]

Optical properties of insulators can be dominated by trace-level impurities and/or other defects that may be difficult to identify using direct chemical analysis. The present work investigates the origins of coloration in BaSO 4 powders following exposure to high energy photons (1.33 and 1.17 MeV γ from a 60Co source)using a through the combination ofexperimental and computational predictions of defect energies and a suite of complementary experimental techniques. We conclude that a slight greying observed in some BaSO 4 powders is caused by activation of sulfate radicals that are stabilized by nearby barium vacancies or trace amounts of sodium substitution on the barium site. Electron–hole pairs activated by exposure to gamma irradiation and trapped by these defect couples lead to visible absorption centered around ∼ 650 nm. Such trapped electronic defects are stable at room temperature but can be 'healed' byeither thermal annealing above 300 °Cor ultraviolet bleaching. Such gamma-induced colorationwill therefore have has no impact on the mass density that dominates radiopacity nor on the chemical or physical properties of BaSO 4 and is not an indication of any sort of toxic contamination. [Display omitted] • Gamma-induced darkening in high purity BaSO 4 linked to compensated sulfate radicals. • Calculated energies of defects align well with observed optical absorption around 650 nm. • Extensive characterization and challenge experiments eliminate other impurities as the cause. [ABSTRACT FROM AUTHOR]

Reactive cold sintering (RCS) is an innovative ceramic consolidation technique that combines a low-temperature reaction with the cold sintering process. In this work, equimolar (CH 3 COO) 2 Ba and (NH 4) 2 SO 4 were homogeneously mixed to obtain a reactive activator abbreviated as RA and then added to barium sulfate (BaSO 4) powder obtaining BaSO 4 – x wt%RA (x = 5, 7.5, 10, 12.5, and 15). Dense (>96 % theoretical) BaSO 4 ceramics were successfully fabricated via RCS of BaSO 4 – x wt%RA at 200℃ with a constantly applied pressure of 250 MPa. The Woolfrey-Bannister method provided quantitative insights into the activation energy, indicating that RA effectively reduced the energy required for densification. The Vickers hardness (1.76 GPa) and coefficient of thermal expansion (CTE, 18.8 ppm/°C) of the RCSed BaSO 4 ceramics were comparable to the high-temperature (850 °C) sintered counterparts. Moreover, finite element analyses confirmed the high CTE value of the RCSed BaSO 4 ceramics holds great promise for high-reliability chip packaging applications. [ABSTRACT FROM AUTHOR]

• Blocking filtration laws are applied to evaluate filter aid filtration data. • Cake filtration law and missing law are identified as relevant process laws. • X-ray microscopy is used to visualize the separation mechanisms. • A separation principle can be assigned to the missing law, for the first time. In this study, the blocking filtration laws introduced by Hermans and Bredée are applied to evaluate filter aid filtration data. A model system is utilized for the filtration experiments, consisting of barium sulphate as the model impurity and diatomaceous earth as the filter aid. Based on the analysis of the filtration data, the relevant process laws are initially identified as cake filtration for the separation of the diatomaceous earth and the so-called missing law for the separation of barium sulphate. The results are substantiated with the aid of X-ray microscopy to monitor the incorporation of the fine particles in the filter aid structure. They demonstrate that the separation of barium sulphate is characterised by both depth migration and accumulation within the growing filter aid structure. The blocking filtration laws derive from a general exponential relationship between blocking rate φ and hight-specific resistance r with the blocking exponent n. Hermans and Bredée presented first the solutions for the four blocking exponents n = 2 (complete blocking), n = 1.5 (standard law), n = 1 (intermediate law) and n = 0 (cake filtration). Gonsalves later supplemented the solution for n = 0.5 from a purely logical point of view and called it the missing law, as he could not find a model behind it himself. Thus, for the first time, this study assigns a separation principle to the missing law, which until now has only been discussed theoretically. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes have been broadly studied due to their wide applications in various electrochemical devices. In the present work, the electrical properties of polyaniline and its composites with BaSO 4 have been studied. The polymerization of aniline monomer via the ordinary chemical polymerization process showed an amorphous structure. Whereas, in the presence of BaSO 4 as a seed, the aniline is polymerized in an orthorhombic crystalline structure on the BaSO 4 -surface. Two composite samples of PANI and BaSO 4 with different amounts of BaSO 4 (1.5 and 2.5 wt%) were prepared and analyzed using XRD, FT-IR, SEM, and XPS techniques. The ac- electrical studies on the composites showed an enhancement in the electrical conductivity of PANI due to the addition of BaSO 4. Ac- conductivity at frequency 500 kHz, and 100 °C, showed values of 1.9 × 10−3, 5.4 × 10−4, 1.6 × 10−1, and 1.9 × 10−1 S/cm for PANI, BaSO 4 , BaSO 4 /PANI 1.5 wt%, and BaSO 4 /PANI 2.5 wt%, respectively. [ABSTRACT FROM AUTHOR]

Mineral scale refers to the hard inorganic solids nucleated on substrates or deposited from the aqueous phase. The formation and deposition of barium sulfate and strontium sulfate in various industries, such as water treatment and oilfield operations, can significantly impact facility operations, posing serious threats. Machine learning (ML) approaches have been adopted recently in scale threat predictions to address the limitations of conventional scaling prediction models. However, there are few reports on collecting sulfate mineral scaling data, employing ML methods for data analysis, and evaluating the modeling results to gain deeper insights of sulfate mineral scaling process and to improve the accuracy of sulfate scaling threat prediction. Despite comprehensive experimental studies, the literature does not provide adequate guidance for identifying the influence on the solubility of barium sulfate and strontium sulfate under different aqueous environments and actual operating conditions. To this end, this study collected 1600 experimental datasets of barium/strontium sulfate from the literature to construct and evaluate the reliability and versatility of a ML-based model for sulfate solubility calculations. Single neural networks, hybrid neural networks, and optimization algorithms were employed to build solubility prediction models for barium sulfate and strontium sulfate across a wide range of temperatures, pressures, and different ions. The model's applicability in predicting sulfate scaling threats in various actual operating environments demonstrated its broad usability, consistent with its actual performance. This study marks the first stride towards constructing a reliable model for identifying the scaling trends of barium sulfate and strontium sulfate across various operating conditions, underscoring the importance of developing robust and accurate prediction models to address challenges in various industrial systems. [Display omitted] • Utilize multiple hybrid neural networks to establish sulfate solubility model. • Employ novel optimization algorithms to enhance model performance. • MLP-POA model exhibits the highest accuracy in prediction capabilities. • Impurity ion concentrations have the most significant impact on sulfate solubility. • This model can predict sulfate scaling threats in various operating environments. [ABSTRACT FROM AUTHOR]

• A film with average reflectivity and emissivity of 94.73% and 95.96% were prepared. • The film showed super-amphiphobic properties and flexible mechanical performance. • The film showed well friction-resistant and flame-retardant properties. • Cooling performance showed insignificant changes before and after self-cleaning. • Cooling performance showed insignificant changes before and after friction. Ensuring prolonged performance is a challenge in promoting passive daytime radiative cooling materials (PDRCMs) for addressing energy depletion. A single-layer inlay-structured passive daytime radiative cooling composite film (PDRCCF) was introduced with hexagonal boron nitride (h -BN) in polydimethylsiloxane (PDMS) and randomly semi-embedded fluorination-modified barium sulfate (M-BaSO 4) particles on the substrate surface. The optimal sample demonstrated high average reflectivity of 94.73% in the solar spectrum (SS), average emissivity of 95.96% in the mid-infrared wavelength range (MIWR) (2.5–25 μm) and average daytime temperature drop of 4.21°C in cloudy weather, and also exhibited super-amphiphobic, friction-resistant and flame-retardant properties due to the h -BN and M-BaSO 4 particles. This work offers a significant strategy for advancing PDRCMs. [ABSTRACT FROM AUTHOR]

Owing to the characteristics of mineral paragenesis (equilibrium sequence of mineral phases), the hydrochloric acid leach liquors of Sn ores and Sn-containing waste materials typically contain large amounts of Pb. In this study, barium sulfate coprecipitation was employed to efficiently remove Pb from a tin chloride solution. The lead removal efficiency, reaction mechanism, and limitations were investigated by varying the Cl− and SO 4 2− concentrations. The results showed that the structural formula of the precipitates was (Ba x Pb y)(SO 4) 2 (x + y = 2), and its solubility product was in the range of 1 × 10−12–1 × 10−13, indicating that Pb2+ and Ba2+ were more easily precipitated in the form of complex salts. In addition, thermodynamic analysis revealed that when the Cl− concentration was <1 mol/L in the Pb2+–Sn2+–Cl−–H 2 O system, [Pb2+] and [PbCl+] were the primary species. These positively charged species were readily adsorbed onto the surface of BaSO 4 via electrostatic forces, resulting in a significant increase in the Pb content of (Ba x Pb y)(SO 4) 2. Therefore, the Pb removal efficiency significantly improved as Cl− concentration decreased. The lead removal mechanism involves a combination of adsorption and replacement processes. Based on the aforementioned fundamental study, a method involving dechlorination and coprecipitation was proposed to remove lead from an acid leaching solution of Kaldo slag. With the dechlorination via distillation, the Pb removal efficiency could reach 99.9% at 1 mol/L Cl− and 0.5 mol/L SO 4 2−. • The reasons for the distinction in coprecipitation products were explained. • Thermodynamic analysis elucidated the limitation of lead removal by coprecipitation. • The coprecipitation mechanism involved a combination of adsorption and replacement. • A proposed lead removal method had great feasibility in industrial applications. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the shielding effectiveness of a non-toxic double layer of barium sulfate and tungsten with disclosed elemental compositions against diagnostic X-rays. Three variations of the radiation shielding material were created: one mainly composed of tungsten (mW), another mainly composed of barium sulfate (mBa), and a third composed of a blend of barium sulfate and tungsten (W/Ba). The following three types of 1.0 mm protective sheets were used to compare their shielding effectiveness: a double layer with mW upstream and mBa downstream (mW→mBa); a double layer with mBa upstream and mW downstream (mBa→mW); and W/Ba. Moreover, using experimental measurements and Monte Carlo calculations, the shielding effectiveness against 110 kVp X-rays of mBa→mW (0.495 g cm−2) was compared with the corresponding values for a commercially available lead-free protective apron (0.25 mmPb equivalent) and a 0.5 mm pure lead sheet (0.567 g cm−2). The measured and calculated shielding of a mBa→mW double layer was approximately 1% more effective than that of the reverse arrangement and of the mixture. The shielding effectiveness of mBa→mW was 93.66%, which compared with values of 87.22% for the commercially available lead-free apron and 93.86% for pure lead. In conclusion, the 1.0 mm non-toxic radiation shielding sheet having a double-layered structure with barium sulfate upstream and tungsten downstream was approximately 13% lighter than a 0.5 mm thick pure lead sheet but provided an equivalent shielding effectiveness against diagnostic X-rays. • Proof of benefits with double-layered structure (BaSO 4 upstream, W downstream). • BaSO 4 –W shield 1% better than reverse, 13% lighter than 0.5 mm lead, equal protection. • Non-toxic BaSO4–W shield combines high shielding effectiveness and safety. • Promising future for x-ray shielding techniques with optimized double-layered shield. [ABSTRACT FROM AUTHOR]

For the dye-sensitized heterogeneous photocatalytic system, the main challenge is the design of support materials with low cost, good adsorption capacity and facilitated electron transfer ability. Herein, an amorphous/crystalline SnO 2 /BaSO 4 composite with unique leaf-like morphology composed of four protruded corners was developed by an one-pot coprecipitation method at room temperature. The low-cost crystalline BaSO 4 acted as the support material for Eosin Y (EY) sensitization and did not inhibit the light absorption of EY, and the amorphous SnO 2 uniformly coated on BaSO 4 provided good conductivity to benefit for the transport of photogenerated carriers. Therefore, under visible-light irradiation (λ ≥ 420 nm), the EY-sensitized SnO 2 /BaSO 4 showed excellent photocatalytic activity with H 2 -production rate of 263 μmol h−1, which was 7.5 times that of EY or EY-sensitized bare BaSO 4 , and the apparent quantum yield achieved to be 11.2 % at 500 nm. [Display omitted] [ABSTRACT FROM AUTHOR]

• High-speed camera to capture the morphological changes during the growth of bubbles. • A curvature change at the top of bubble may be the essential reason for the transition of bubbling regimes. • The mechanism of gas–liquid environment factors is varied for the change of bubbling regime and size. • There is a special phenomenon with a "cavity" at the top of bubble during bubbling. • The existence of "cavity" may cause a transition of regime in high temperature or aerosol-containing pool. Bubbling at a submerged orifice in pool is one of effective ways to filter radioactive gas in containment. Gas containing radioactive aerosol will rise in bubble column in the form of bubbles to be filtered. Complex environment in pool with high temperature and aerosol will affect the bubbling regimes and sizes, which involve the filtration efficiency by accompanying changes in surface area and floating velocity of bubbles. This paper observes and analyzes the transition between bubbling regimes and sizes at a submerged single-hole orifice in the high-temperature liquid pool containing barium sulfate or titanium dioxide particles through a visual experiment. The influence mechanism of environmental factors such as aerosol particles, temperature of liquid and gas feeding pressure are explored in the experiment. It is concluded that there will be a change in gas momentum force caused by changes in flow rate or pressure and a phenomenon that "cavity" ruptures in high-temperature aerosol suspension, both of which will cause the curvature change at the top of bubble and bubbling regimes change accordingly. [ABSTRACT FROM AUTHOR]

At birth, calves are functionally monogastric and remain so for the first weeks of life. Milk in the rumen may cause indigestion, diarrhea, and reduced growth. Calves are often fed cold milk from a large-aperture teat, but warm milk and sucking behavior are believed to trigger the esophageal reflex. The aim of this study was to use radiography to estimate the lowest milk temperature that can be given to dairy calves at high and low intake rates without causing milk in the rumen. Our hypothesis was that cold milk drunk at high speed would cause insufficient closure of the esophageal groove and hence milk in the rumen. Fifteen Norwegian Red calves, 9 to 27 d of age, weighing between 45.5 and 71.0 kg, were tested according to the response surface pathway design. Each calf was offered 4 L of milk from both a small- (2 mm) and a large-aperture (19 mm) teat. The milk contained barium sulfate, and radiography was applied before, during, and after the milk meal. Following radiography, the calves were returned to a group pen and observed for 2 h using continuous live behavioral observation to detect signs of abdominal pain or discomfort. Starting with a low number of subjects and increasing this number with increasing design levels reduces the sample size without reducing the statistical power. The minimum milk temperature was estimated to be 8°C. No behavioral signs of pain or discomfort were observed, but shivering was noted in several calves drinking 8°C milk. These results strengthen the argument that calves can be fed large milk meals without risk of causing milk in the rumen, even cold milk drunk at high speed. [ABSTRACT FROM AUTHOR]

• Mixing effects on barium sulfate precipitation test process course were investigated. • Comparison of several literature barium sulfate precipitation kinetics is presented. • Two reactor types of three different sizes each are considered. • Mixing in jet reactors was generally found to be faster than precipitation. • Both large eddy simulations and k-ε model can be used for precipitation modeling in jet reactors. The paper presents an application of large eddy simulations (LES) to predict the course of barium sulfate precipitation carried out in jet reactors and basic guidelines for a reactor design. The reactors in question were of different geometries and made in different sizes in order to achieve high mixing intensities and low residence times in a mixing chamber, thus enabling to reflect and understand the effects of process conditions and influence of mixing on the course of precipitation better. The system's behavior is explained using experimental and simulation results. Simulations were validated by comparing LES model predictions with experimental data, as well as the k-ε model supplemented with the multiple-time-scale mixing model. The BaSO 4 precipitation results obtained with a CFD based precipitation model are in a very good agreement with experiments and are used to distinguish the jet reactors that allow obtaining a product with favorable characteristics, i.e., the smallest mean particle size. In general, the smallest studied reactors are found to best meet this criterion. A special attention is given to precipitation kinetics models, the choice of which can significantly affect predictions' accuracy. Several literature precipitation kinetics models were tested and the ones working best in jet reactors were identified. Finally, a time-scale analysis of process controlling mechanisms is highlighted and the assumption of negligibility of the subgrid closure for precipitation in LES is validated. [ABSTRACT FROM AUTHOR]

• Shear controllable synthesis of particles realized by using a lobed inner cylinder Taylor-Couette reactor. • The use of lobed inner cylinder enhances the shear through the local impinging jet flow. • Synthesised particle size strongly correlates with the local turbulent dissipation rate. A novel lobed inner cylinder assembled in Taylor-Couette flow reactor (LTC) has been adopted to synthesize barium sulfate particles. The fluid dynamics that affects synthesis of particles using both the LTC and the classical Taylor-Couette flow reactor (CTC) was investigated through CFD modelling and experiments. The results have demonstrated that the Taylor vortices and turbulence induced shear rate distribution in the reactors have a significant influence on the final particle size distribution. The narrower shear rate distribution in the LTC is beneficial to the synthesis of particles with smaller size. The local turbulence intensification in the intra-Taylor vortices in the LTC effectively reduces the low shear strain regions. A strong correlation between the synthesized particle size and the local turbulent dissipation rate is existing. Shear induced by small turbulent eddies can inhibit particle growth. The LTC can be used for effectively shear controllable synthesis of particles. [ABSTRACT FROM AUTHOR]

The aim of this study is to obtain and characterize starch films structurally modified by in situ precipitation of BaSO 4 combined with mechanical activation of casting dispersion in a rotor-stator device. By the rheological method, it was found that the modification causes a decrease in the ability of casting dispersions to structure over time. Composite films with a filler content of 0 %–15 % (w/w) were characterized using optical and SEM microscopy, FT-IR spectroscopy, and tensile and moisture resistance testing data. The maximum increase in strength (by 70 %) and elongation at break (by 870 %) is achieved with a filler content of 5 % and 15 %, respectively. An increase in the filler content to 5 % causes an increase in starch recrystallization rate, but at concentrations above 5 % of BaSO 4 , it inhibits retrogradation. The films obtained by mechanical activation with optimized parameters were uniformly translucent, had lower water vapor permeability than films made from starch alone, had high flexibility, and did not warp or shrink. The developed high-performance, environmentally friendly method can be recommended for the large-scale production of starch-based composite materials. [Display omitted] • Starch-BaSO4 composite films were obtained by in situ precipitation and mechanоactivation. • BaSO4 at a content of 0–5 % increases the films strength and the retrogradation rate. • BaSO4 at 5–15 % inhibits starch retrogradation. • Extremely high elongation is observed at BaSO4 content of 5–15 %. • BaSO 4 -containing films had lower vapor permeability than pure starch films. [ABSTRACT FROM AUTHOR]

Barium sulfide has been widely accepted as a useful barium compound in many fields. To reduce the emission of CO 2 through tail gas during the current industrial production of barium sulfide by the black ash method, a new clean process for barium sulfide preparation by barite reduction using elemental sulfur is proposed. Herein, we report a study on the kinetics and thermodynamics of the thermal decomposition of barium sulfate by elemental sulfur. The mechanism of this complicated gas–solid reaction was investigated under non-isothermal conditions, at different heating rates. Four isoconversional methods were used to determine the activation energy. The mechanism model of the barium sulfate decomposition was confirmed using the double equal–double step method. The results suggested that the barium sulfate decomposition followed the Jander D3 spherical symmetry model; the order of the reaction (n = 1.06) was determined using the Carne equation. Unlabelled Image • A co-production scheme for converting barium sulfate to barium sulfide, using elemental sulfur, is proposed. • The mechanism of thermal decomposition of barium sulfate by elemental sulfur was studied using thermodynamics simulation. • Non-isothermal decomposition of barium sulfate was studied at different heating rates. • Kinetics parameters were determined using isoconversional methods. [ABSTRACT FROM AUTHOR]

The authors carried out a comparative analysis on the diffuse reflectance spectra within 250–2500 nm and on the solar absorptance of BaSO 4 , ZnO, and TiO 2 reflective powders. The authors also considered the powders' change after irradiation with electron fluence of (1 and 3) × 1016cm−2 with 30 keV and recorded the spectra in a vacuum on the spot (in situ). It has been established that BaSO 4 powder exceeds ZnO and TiO 2 both in its initial optical properties and in its radiation stability. BaSO 4 powder can efficiently function as a pigment for spacecraft thermal control coatings. Additionally, the authors performed the solid-state modification of BaSO 4 powder with SiO 2 and ZrO 2 nanoparticles. An increase in the radiation resistance of the modified BaSO 4 powder is shown to be 1.65–1.93 times in comparison with the non-modified one. • Diffuse reflectance within 250–2500 nm for BaSO 4 is higher than for ZnO and TiO 2. • BaSO 4 powders have higher radiation stability compared with ZnO and TiO 2. • While irradiating BaSO 4 , reflectance coefficient increases in the near-IR region. • Modification with nanoparticles can increase the radiation stability of BaSO 4. [ABSTRACT FROM AUTHOR]

• Optimum filler doped polymer dosage was determined by Multi-Response Optimization. • BaSO 4 doped polypropylene provided 67.11% lower electrical resistance. • BaSO 4 doped polypropylene should be preferred for thermally insulated concrete. • Highest water resistance was achieved with the use of talc doped polypropylene. The use of filler materials in industrial polymers is becoming increasingly widespread in order to overcome the disadvantages of polymers loss of strength. This study proposed a methodology to analyze the effect of filler-doped polymers on the concrete features. The results of the study showed that Barium Sulfate (BaSO 4) doped polypropylene added concrete with 30% polymer/cement ratio has 51.03% lower thermal conductivity and 147.99% higher 28-day compressive strength than the reference concrete. It is determined that Calcium Carbonate doped polyethylene (CaPE) and glass fiber doped polypropylene (GFPP) gave the highest electrical resistance to the concrete. [ABSTRACT FROM AUTHOR]

• LME model for semi-batch precipitation in stirred-tanks is presented. • Model considers stirrer type, size and rotational speed. • Model accuracy is validated with experimental comparison setup. • Mixing zone parameterized by pipe-in-pipe geometries. A zone model for the semi-batch precipitation process of sparingly soluble salts in stirred-tank reactors is presented. The low product solubility of these substances leads to high levels of supersaturation during the process. Consequently, nucleation and growth rates are fast and solids formation only takes place in a part of the reactor close to the feed pipe. The presented local mixing environment (LME) model extends an existing model for semi-batch processes, which consists of two zones. In the mixing zone, a steady-state plug-flow reactor (PFR) is used to imitate the local flow environment of the feed. The tank is approximated as a well-mixed storage tank outside the mixing zone. Exchange streams between the two zones are estimated by dimensional analysis considering stirrer type, size and rotational speed. The correctness of the two-zone hypothesis and the accuracy of the LME model is validated by barium sulfate precipitation in an experimental comparison setup using different stirrer types, rotational speeds and feed rates. The PFR is represented in the experiments as a pipe-in-pipe reactor in jet-in-cross-flow (JICF) or coaxial-flow (COAX) arrangement. The experimental results show that the semi-batch precipitation of sparingly soluble salts in stirred-tanks can be successfully simplified by the assumption of a PFR mixing zone. The LME model is simple to implement, scalable and reaches acceptable results in the experimental validation. It is therefore a promising model for future application in process simulation of industrial precipitation processes. [ABSTRACT FROM AUTHOR]

The authors propose a model for the physical processes that occur under ionizing irradiation in BaSO 4 powders modified with SiO 2 , Al 2 O 3 , and ZrO 2 nanoparticles. The model is based on physical representation and on the experimentally obtained correlation between spectra, solar absorptance, nanoparticle concentration, and accelerated electron fluence. The model includes four constituents, two of which describe accumulation of defects solely for initial irradiated powders. In case of irradiated BaSO 4 powders, accumulation processes are described via all constituents. The changes in optical properties have been predicted and calculated under electron spectra exposure at the geostationary orbit within 15 years period. [ABSTRACT FROM AUTHOR]

• Steady-state precipitation model for flowsheet simulation is presented. • Experimental validation is performed by barium sulfate precipitation. • Influence of recycle streams on precipitation in micro mixers is investigated. • Recycled particles influence precipitation only if a critical density is exceeded. Precipitation of sparingly soluble salts is an important process to produce solid products as color pigments or catalysts. High levels of supersaturation are obtained in this process during the mixing step. Consequently, reaction timescales are fast and mixing often influences the product particle size distribution (PSD). In this work, we present a generic model for flowsheet simulation of steady-state precipitation of sparingly soluble salts. Model validation is performed by experiments involving barium sulfate precipitation from aqueous solutions in a confined imping jet mixer (CIJM). Furthermore, experimental and simulative methods are applied to investigate the influence of recycle streams on the product PSD. The experiments show an increase in the average particle size for high recycle flows which is well-predicted by the model. We, furthermore, demonstrate by simulations that recycled particles influence the supersaturation buildup in the CIJM only if a critical particle density is exceeded. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Objectives: We conducted this study to characterize the frequency of insertion-, localization- and removal-related events and their clinically significant consequences among Nexplanon® (etonogestrel radiopaque contraceptive implant) users in the United States during standard clinical practice.Study Design: The Nexplanon Observational Risk Assessment (NORA) study was a large, prospective cohort study conducted in the United States. A total of 428 Health Care Professionals (HCPs) who had completed the Nexplanon clinical training program recruited women who were newly prescribed Nexplanon. We collected data on insertion-, localization- and removal-related events experienced during routine clinical practice via questionnaires completed by patients and HCPs. Recruitment began in December 2011 and follow-up ended in October 2017. Data analysis characterized the frequency of procedure-related events.Results: We collected data on 7364 insertion procedures. The incidence of incorrect insertion (i.e., initially unrecognized non-insertion, partial insertion or deep insertion) was 12.6 per 1000 insertions (95% CI, 10.2-15.5). Pins and needles/numbness in the arm/hand/fingers was the most common patient-reported event. We obtained data on 5159 removal procedures, of which all were successful but one (due to the location of the implant in deep muscle tissue). No implants were localized outside the arm. The most common challenge reported by HCPs during implant removal was encasement of the implant within fibrotic tissue.Conclusions: Events associated with the insertion, localization and removal of the Nexplanon contraceptive implant were rare and their clinical consequences were generally not suggestive of serious injury.Implications: This study is the largest prospective evaluation of events associated with insertion and removal of Nexplanon during routine clinical practice. It demonstrates that complications associated with insertion and removal of Nexplanon are rare when performed by trained clinicians. [ABSTRACT FROM AUTHOR]

• Study of a continuous precipitation reaction in an ultrasonic micro-reactor. • Obtained particle size distribution is controlled by the ultrasound parameters. • Pulsed ultrasound is able to prevent clogging and provides temperature control. • An effective ultrasound treatment time of 12.5% is identified for optimum operation. Ultrasonic micro-reactors are frequently applied to prevent micro-channel clogging in the presence of solid materials. Continuous sonication will lead to a sizeable energy input resulting in a temperature increase in the fluidic channels and concerns regarding microchannel degradation. In this paper, we investigate the application of pulsed ultrasound as a less invasive approach to prevent micro-channel clogging, while also controlling the temperature increase. The inorganic precipitation of barium sulfate particles was studied, and the impact of the effective ultrasonic treatment ratio, frequency and load power on the particle size distribution, pressure and temperature was quantified in comparison to non-sonicated experiments. The precipitation reactions were performed in a continuous reactor consisting of a micro-reactor chip attached to a Langevin-type transducer. It was found that adjusting the pulsed ultrasound conditions prevented microchannel clogging by reducing the particle size to the same magnitude as observed for continuous sonication. Furthermore, reducing the effective treatment ratio from 100 to 12.5% decreases the temperature rise from 7 to 1 °C. [ABSTRACT FROM AUTHOR]

The deep and perforating lymphatic anatomy of the upper limb still remains the least described in medical literature. Six upper limbs with the axillary tissue were harvested from three unembalmed human cadavers amputated at the shoulder joint. A small amount of 6% hydrogen peroxide was employed to detect the lymphatic vessels around the deep palmar arch, radial and ulnar neurovascular bundles. A 30-gauge needle was inserted into the vessels and they were injected with a barium sulphate compound. Each specimen was dissected, photographed and radiographed to demonstrate deep lymphatic distribution of the upper limb. Continuing from the deep lymph vessels of the hand, single or multiple deep collecting lymph vessels have been found along the radial, ulnar, anterior and posterior interosseous neurovascular bundles in the forearm, brachial and deep branchial neurovascular bundles in the upper arm. During their courses, lymph nodes were found setting in the trunk of the radial, ulnar and brachial lymph vessels near or in the cubital fossa, and in the axillar. Perforating lymph vessels have been found near the wrist and in the cubital fossa, which linked the superficial and deep lymph vessels. The direction of lymphatic drainage was from the deep to superficial or superficial to deep vessels. The deep lymphatic anatomy of the upper limb has been described. The results will provide an anatomical basis for clinical management, educational reference and scientific research. [ABSTRACT FROM AUTHOR]

Abstract BaSO 4 powders demonstrate high reflecting capacity in the UV, visible, and near infrared regions of the spectrum and appear to be promising pigments for thermal control coatings of space vehicles and household paints. Their application in a wide range of fields is due to the constant impact of ionizing radiation. In the experiment under study, BaSO 4 powders were heated in the atmosphere at T = 100, 400, and 800 °C for the purpose of increasing their radiation stability. It has been established that the highest resistance to accelerated electrons corresponds to the powders preheated at 400 °C. The reflecting capacity of BaSO 4 powders after heating at 100 and 400 °C decreases insignificantly. Warming at 800 °C leads to a deterioration in both reflecting capacity and radiation stability compared with the initial powder. Highlights • Heating BaSO 4 at 400 °C increases the stability of optical properties under radiation. • Heating BaSO 4 at 800 °C significantly decreases the reflectance in UV region. • Reflectance in the near IR region significantly increases after heating at 800 °C. • The sulphate centres' absorption bands are registered for the after-irradiated spectra. [ABSTRACT FROM AUTHOR]

Purpose: To design a spine phantom suitable for fusion of MR neurography (MRN) with interventional flat panel computed tomography (FPCT) images from tissue-equivalent agarose gels and artificial nerves in MRI, including material with equal attenuation to bone in computed tomography (CT).Methods: T1-/T2-relaxation times of target tissue were determined in vivo (n = 5) using MR mapping-techniques. Serial dilution of castor oil lipogels was performed ex vivo in order to define correct composition for tissue-equivalent relaxation times. Similarly, serial dilution series of calcium carbonate (CaCO3) and barium sulphate (BaSO4) in synthetic resin were used to adjust radiodensity of selected vertebral bodies (L1-L5) and sacrum in CT. Nerve tissue was simulated with agarose-impregnated polyethylene fibers. Spine phantom was assembled using respective components in anthropomorphic geometry. A fat-saturated, T2-weighted 3D SPACE STIR sequence was acquired for MRN and subsequently fused with an on-site FPCT scan of the phantom.Results: In vivo T1-/T2-values for fat tissue were found to be at 394 ± 16 ms and 161 ± 16 ms, corresponding to a castor oil concentration of 50%. Analogously, bone marrow-equivalent values were measured at 822 ± 21 ms and 67 ± 6 ms, simulated with 40% castor oil. Cortical bone-like radiodensity of 1'115 ± 80 HU was achieved for artificial bone with 30% CaCO3 and 1.5% BaSO4. Simulated nerves were successfully depicted in MRN and fused with FPCT, combining optimal contrasts for nerves and bones on-site.Conclusions: The customized phantom showed analogous tissue contrasts to in vivo conditions in both MRN and FPCT, facilitating simulations of fusion-image guided spine interventions. [ABSTRACT FROM AUTHOR]

Abstract A simple, accurate, and fast flow-batch procedure employing photometric detection for the determination of sulfate in fuel ethanol was developed. After the formation of soluble barium sulfate in alcoholic medium, the remaining barium forms a product with dimethylsulfonazo III (DMS), the absorbance of which was monitored at 655 nm directly in the reaction chamber. The proposed procedure does not require any sample treatment such as dilution. Under the optimized conditions, the technique offers the advantages of low waste generation (<5 mL), sampling throughput of 35 h−1, linear response from 0.1–1.5 mg L−1 sulfate, and a limit of detection (95%) and coefficient of variation (n = 6) of 48 μg L−1 and 1%, respectively. The accuracy was assessed by comparison of results with those obtained by ion-chromatography; no significant difference was observed at the 95% confidence level. Graphical abstract Unlabelled Image Highlights • Novel procedure for sulfate determination in fuel ethanol without sample treatment • Miniaturized and cost-effective system for point-of-care determination of sulfate • Highly sensitive and robust procedure implemented with a flow-batch setup • Exploitation of DMS-Ba color bleaching by soluble BaSO 4 formation in ethanol • It meets green chemistry guidelines concerning to reagent use and waste generation. [ABSTRACT FROM AUTHOR]

Unbaffled U-shaped mesoscale oscillatory flow reactors (meso-OFRs) were developed to prevent solid deposition and prepare uniform barium sulfate (BaSO 4) nanoparticles with environmental protection function. The results showed that the oscillation significantly reduced granular deposition; the greater the intensity of the oscillation, the faster it reached uniformity, and the less likely the granules were to be deposited. These results can be explained by the formation of a larger vortex size, which can strengthen the turbulent mixing of fluid in the reactor, promote the interaction and forced mixing between the liquid phase and solid particles, enhance the internal shear stress of the fluid, and contribute to the secondary suspension of solid particles and the disintegration of particle agglomeration. The prepared BaSO 4 nanoparticles with oscillation were smaller in size and lower in pressure drop than those produced without oscillation, which conclusively illustrated that oscillation effectively prevented channel deposition and clogging. [Display omitted] • The meso-OFR could prevent solid deposition and prepare uniform nanoparticles. • The formation of vortex contributed to the secondary suspension of solid particles. • The prepared BaSO 4 nanoparticles were smaller in size and lower in pressure drop. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of barium sulfate nanoparticles with a one-step hydrothermal method. • Barium sulfate nanoparticles as an excellent photocatalyst for the degradation of organic dyes. • Investigation of cell bio-toxicity of the barium sulfate nanoparticles on the B16F0 cell line. The article introduces a novel method for the production of barium sulfate nanoparticles (BaSO 4 -NPs), which was executed utilizing a particular methodology that entailed the reaction between barium chloride and sodium sulfate. FT-IR, PXRD, UV–Vis, FESEM/EDX, TEM, and PSA analyses were employed to approve the fabrication of BaSO 4 -NPs. The XRD pattern showed that the NPs had a higher occurrence of the orthorhombic phase with the Pnma space group. Furthermore, the synthesis of BaSO 4 -NPs was confirmed utilizing FTIR analysis, which displayed their strong bands. The FESEM pictures of BaSO 4 -NPs exhibited spherical morphology and uniform distribution. The proficiency of photocatalysis by BaSO4-NPs was evaluated in the degradation of Methylene Blue (MB) dye. After 150 min, the observed degradation percentage was 89%. In the current research, the cytotoxicity of the BaSO 4 -NPs was studied on normal mouse fibroblast NIH3T3 cell and cancer mouse melanoma B16F0 cell lines and the IC 50 value was 823.8 µg/mL for cancer B16F0 cells and the results revealed a slight reduction in the viability of cancer cells compared to normal cells. [ABSTRACT FROM AUTHOR]

The shape, size, and connection of uterine vessels change during pregnancy. The mechanism of luteolysis and vascular anastomosis between fetuses in twin pregnancies differs among species. Angiography is used to evaluate the anatomical structure of vessels. In this study, angiography was performed on the uterine vessels, in open, single and twin bearing ewes. Sheep uteri were collected from the slaughterhouse and the gestational age of fetus was determined using ultrasound. Five gestational periods (30–39, 40–49, 50–59, 60–69 and 70–79 days of pregnancy) were considered. Barium sulfate with a concentration of 30% in warm water was used as the contrast agent. The injection volume and angiocath gauge were proportional to the size of the pregnant uterus. The uterine arteries and their branches were accurately observed on radiographs. Additionally, small branches of arteries and even small vessels of caruncles were clearly defined. Unilateral anastomosis was observed between the uterine artery and ovary. Anastomosis occurred between the middle uterine arteries from day 30 of pregnancy. There was no anastomosis between the twins' fetal sacs at days 40–60 of pregnancy. These results demonstrate that angiography is a useful method for imaging the development of uterine arteries during pregnancy in sheep. • The ovaries were supplied with blood from the ipsilateral uterine arteries. • There was no anastomosis between the left and right uterine arteries in non-pregnant sheep. • Anastomosis was observed between the left and right uterine arteries from day 30 of pregnancy onward. • Anastomosis was not observed between the gestation sacs of twins. [ABSTRACT FROM AUTHOR]

• A rapid & eco-friendly surface mineralization approach was applied on NF membrane. • BaSO 4 -mineralized membrane showed excellent flux & rejection.. • The mineralized membrane also displayed better antifouling ability with higher FRR. • The rejection of mineralized membrane was very stable for multiple filtration cycles. In this study, an environmentally friendly and rapid surface modification method known as surface mineralization was adopted to alter the polyamide (PA) layer of commercial NF270 thin film composite (TFC) membrane, aiming to improve its characteristics for enhanced desalination process. An alternate soaking process was applied on the membrane surface by using barium chloride solution and sodium sulfate solution at varying concentrations (0.01 M, 0.05 M and 0.1 M). The reaction of these two salts can form a layer of barium sulfate (BaSO 4) minerals atop the PA layer via an ionic interaction. Our result revealed that the best-performing membrane could be developed using salt solutions at 0.05 M with its water contact angle descended to 33.5° compared to the pristine membrane of 46.4°. Furthermore, the surface roughness of the BaSO 4 -mineralized membrane was reported to be higher than the pristine membrane. The increase in surface roughness together with improved surface hydrophilicity yielded the BaSO 4 -mineralized membrane to exhibit 12% higher water flux than the pristine membrane. Nonetheless, the difference in Na 2 SO 4 rejection before and after surface mineralization was not found to be statistically significant owing to the high Na 2 SO 4 rejection of the control membrane. The BaSO 4 -mineralized membrane also achieved excellent performance in filtering solutions containing sodium alginate and showed very stable salt rejection for multiple cycle of combined chemical cleaning and water filtration process. These results highlighted the potential of the surface mineralization process in overcoming the trade-off effect between water flux and selectivity of TFC membrane. [ABSTRACT FROM AUTHOR]

The current research attempted to design and evaluate sustained stomach-specific ofloxacin delivery by single-unit hydrodynamically balanced system (HBS)-based floating capsules. These HBS-based floating capsules of ofloxacin were prepared using two oppositely ionic polymers, namely cationic-natured low molecular mass chitosan (LMMCH) and anionic-natured carboxymethyl tamarind gum (CMTG). FTIR results indicated the in situ formation of a polyelectrolyte complex in-between two oppositely charged polymers (i.e. , in-between –NH 2 group of the cationic natured LMMCH and –COOH groups of the anionic natured CMTG) and the nonexistence of any drug-polymer interaction(s) within these formulated ofloxacin HBS capsules. All these LMMCH-CMTG ofloxacin HBS capsules exhibited drug content uniformity, a sustained in vitro drug-releasing profile over 10 h. The ofloxacin HBS capsules (formulated with 75 mg LMMCH and 25 mg CMTG), which was selected as best formulation (for further studies), exhibited excellent in vitro floatation behaviour in SGF (pH 1.2) over 6 h without any floating lag-time, whereas the same formulation containing barium sulfate (100 mg) instead of drug demonstrated prolonged stomach-specific gastroretention in an in vivo X-ray imaging study using rabbits. Therefore, these types of HBS floating capsules can be useful for stomach-specific gastroretentive floating delivery of other drugs. [ABSTRACT FROM AUTHOR]

• M−BC/BaSO 4 composites with excellent amphiphobic monolith properties were prepared. • They achieved a WCA of 154° and OCA of 145.5° for the surface. • They achieved a WCA of 153.5° and OCA of 143.5° for the internal section. • They showed average reflectivity and emissivity of 97.75% and 95.74%, respectively. • They showed insignificant changes in cooling performance after self-cleaning. To tackle the daytime radiative cooling performance (DRCP) degradation of passive daytime radiative cooling materials (PDRCMs) due to contamination from aqueous or oily contaminants, modified three-dimensional porous composites of bacterial cellulose (BC) and barium sulfate (BaSO 4) were fabricated by a unidirectional freeze-casting process and silanization modification. The modified BC/BaSO 4 (M−BC/BaSO 4) composites exhibited average reflectivity of 97.75%, average emissivity of 95.74%, and remarkable amphiphobic monolith properties with a water contact angle (WCA) and oily contact angle (OCA) of 154° and 145.5° for the surface and those of 153.5° and 143.5° for the internal section, respectively. They also exhibited insignificant changes in the DRCP before and after self-cleaning, achieving an average and maximum temperature drop of 10.40°C and 16.38°C before self-cleaning and those of 9.92°C and 16.40°C after self-cleaning, respectively. This work provides a new strategy for sustainable PDRCMs in practical applications. [ABSTRACT FROM AUTHOR]

• Steam can oxidize the deposited carbon generated by thermal decomposition of methane. • The effect of operational parameters on the reduction by methane was investigated. • The effect of impurity on the reaction using barite ore and natural gas was investigated. • The intrinsic kinetic parameters were obtained using the shrinking unreacted core model. • At high temperatures and methane concentrations, steam enhanced the reduction rate. Methane gas decomposes at high temperatures and produces carbon as a result. The deposited carbon causes problems during the process. In this study, the reduction of barium sulfate powder using methane was studied and steam was used to remove the carbon produced during the reaction. The effect of temperature and methane concentration on the reaction rate was investigated at two different conditions, using 20 vol % steam and without steam at operating temperatures in the range 850–1000 °C. When steam was used, methane concentration was selected in the range 19–40 vol %, while it was 21–78 % in the absence of steam. The experimental data was interpreted using the "shrinking unreacted core model" and intrinsic kinetic parameters of the reactions were determined. The reaction order and activation energy were calculated to be 1 and 145.5 kJ/mol in the absence of steam and 1.5 and 179.6 kJ/mol in its presence, respectively. From the obtained rate equations, it was found that the reaction rate without steam was always faster than the reaction rate in the presence of steam. [ABSTRACT FROM AUTHOR]

Highlights • Sulfite promotes homogenous nucleation of barite. • Sulfite oxidation does not adequately explain promotion. • At low S, c axis growth is most impacted. • Promotion is most likely due to activation energy barrier reduction. Abstract In this manuscript we investigate an inorganic, anionic promoter of barium sulfate crystallization. Sulfite ions are found to promote barium sulfate crystallization at low concentrations. Turbidimetric experiments show homogenous nucleation promotion and AFM results show possible 2D nucleation promotion in the presence of sulfite ions. Growth promotion appears to be mainly in the c -axis relative to the other faces according to morphology results at low S values. Analysis of the sulfite ion impact by assuming it completely oxidizes to sulfate did not adequately explain all experimental results, suggesting that these ions also interact in some other way. One mechanism by which sulfite might promote barium sulfate crystallization is by promoting de-solvation of the barium ion by weakly complexing with it. [ABSTRACT FROM AUTHOR]

Abstract The exploitation of field naturally, leads to decrease the productivity of wells, to continue this exploitation with the best conditions, it is essential to pass to the stage of secondary recovery. The injection of water in reservoir is the most used method in the recovery of oil; unfortunately, there is an incompatibility between the injection water and the reservoir water, which poses a lot of problems such as training mineral deposits. The reservoir waters may contain alkaline ions and be brought into contact with the wash water which contains sulfate ions. The injected water eventually reaches the producing wells and in these wells the mixture is made and the precipitation of barium sulfate (BaSO4) takes place. The crystals then stick in the walls of the tubings, in a process that may be similar to that of sodium chloride, but this time the problem is more serious because it is a very compact deposit insoluble in the water also in acids. Deposits which formed during production and shipping represent a real calamity against which oil producers have been fighting for several decades, deposits causing irreversible damage particularly dangerous for bottom production facilities such as surface and sometimes for the rock itself. [ABSTRACT FROM AUTHOR]

Abstract Mineral scale deposition is a water-associated production threat for oil and gas productions. Scale deposition can lead to pipe throughput reduction and change in facility surface properties. Scale inhibitors are widely used in oilfield operations to control scale deposition. Fe(II) (ferrous) species is commonly encountered in oilfield produced waters and it is widely recognized that the presence of Fe(II) can impact the performance of scale inhibitors. However, the existing experimental results of Fe(II) impact on scale inhibitors are controversial, especially in barium sulfate system. This is partially due to the difference in dissolved oxygen level among different studies since a trace amount of dissolved oxygen can readily oxidize Fe(II) into Fe(III). In this study, a rigorously-maintained laser-based anoxic experimental setup was adopted to evaluate the impact of Fe(II) species on scale inhibitor performance in controlling barium sulfate scale. The anoxic setup utilized argon gas purging and reducing chemical addition and can maintain a dissolved oxygen level in μg L−1 (ppb) level. The experimental results suggest that at an anoxic condition, the presence of Fe(II) has a detrimental impact on the performance of scale inhibitors and such impact varies with different types of scale inhibitors. Solution pH and temperature can also affect the Fe(II) impact on scale inhibitors. In addition, two common oilfield chelating chemicals, i.e., EDTA and citrate, have been evaluated for their roles in reversing the detrimental impact of Fe(II) on scale inhibitors. It shows that at the experimental condition only citrate can effectively reverse the adverse impact of Fe(II) on scale inhibitor. This study provides the experimental approach and technical insights for evaluation of scale inhibitor performance in an anoxic condition. Graphical abstract Image 1 Highlights • A rigorous anoxic setup to study Fe(II) impact on scale inhibitor performance. • This setup can control dissolved oxygen in ppb level at elevated temperatures. • Fe(II) has a detrimental impact on phosphonate-based scale inhibitors. • Solution pH and temperature can affect Fe(II) impact on scale inhibitors. • Citrate can reverse the adverse impact of Fe(II) on scale inhibitors. [ABSTRACT FROM AUTHOR]

Abstract The bio-composites of poly (lactic acid) (PLA) involving a varied mass fraction of precipitated barium sulfate (BaSO 4) were prepared via melt-compounding and subsequent injection molding. The morphologies, impact toughness and thermal properties of the composites were investigated carefully, and the toughening mechanism was emphasized by a combination of BaSO 4 content and the crystallization ability. Results showed that an adequate amount of BaSO 4 could disperse homogeneously in PLA matrix with well-bonded interfaces. The impact toughness was increased significantly by 52.7% due to added inorganic particles as well as the increased actual crystallinity of the composites. The added BaSO 4 let the cold crystallization occur earlier (shifting to low temperature) while suppressing the cold crystallinity of PLA phase. Such inhibition effects derived from the increased inorganic filler were then further explored and confirmed by the kinetic analysis on the cold crystallization under non-isothermal conditions. Indeed, the added BaSO 4 increased the crystallization half-time and crystallization parameter of F(T) based on Mo equation. Moreover, the activation energy on cold crystallization was strengthened along with the increasing BaSO 4. It seemed that there is little change in the reaction order of PLA/BaSO 4 bio-composites, following the unique reaction thermal decomposition, whereas the activation energies were decreased steadily based on Carrasco method. Graphical abstract The graphical abstract showed the morphological structures, particle size, and distributions, the effect of BaSO 4 content on the impact toughness, as well as the activation energy as a function of relative crystallinity. Image 1 Highlights • Precipitated barium sulfate can disperse homogeneously with well-bonded interfaces in PLA matrix. • The impact toughness is improved remarkably higher than 50%. • The added inorganic fillers restrain the cold crystallization. • Increased barium sulfate don't change reaction order but decreased activation energy of thermal decomposition. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Mixing BaSO 4 with TiO 2 improves the photocatalytic performance by scattering of UV light. • CaCO 3 revealed lead to a stabilization of trapped charge carriers on TiO 2. • Sodium ions reduced the activity of TiO 2 by fast charge recombination. Abstract Building materials employing TiO 2 as photocatalyst usually contain several additives. The interplay of the additives and the photocatalytic NO degradation has been rarely investigated, although it is of utmost importance for the design of new highly active materials. Hence, in the present study the effects of such additives (BaSO 4 , CaCO 3 , and Na 2 CO 3) on the photocatalytic activity and on the charge carrier dynamics have been evaluated. The degradation of nitric oxide (NO) was studied employing a standardized photocatalytic activity test (ISO 22197-1) and the charge carrier kinetics were observed by transient absorption spectroscopy. TiO 2 -additive powder samples were obtained by grinding pure anatase TiO 2 with a single additive with varying volume composition. Overall, the obtained apparent quantum yields of the samples correlated well with the charge carrier concentration. Moreover, BaSO 4 has proven its chemically inert character. However, the optical properties of the powder samples containing BaSO 4 lead to relatively high photonic efficiencies even with low TiO 2 content. TiO 2 -BaSO 4 samples with only 25% TiO 2 showed nearly the same quantum yield for the NO degradation as the pure photocatalyst. The reason for the high photocatalytic activity is the strong absorption of UV-light caused by the scattering inside the powder samples. The charge carrier kinetics of TiO 2 after the addition of Na 2 CO 3 and CaCO 3 revealed two different chemical effects of the additives. Na 2 CO 3 reduced the apparent quantum yield of the TiO 2 samples due to the fast recombination of charge carriers (identified by a fractal kinetics fit). On the other hand, the presence of CaCO 3 had a beneficial influence on the stabilization of trapped charge carriers in TiO 2. [ABSTRACT FROM AUTHOR]

Sulphate is a very hydrophilic anion, and, therefore, difficult to be selectively determined in aqueous solution with a coated sensor. Zinc(II) 2,3,9,10,16,17,23,24-Octatosylaminophthalocyanine was used for the first time as a sensitive coating. Selectivity to sulphate regarding chloride was not enough to ignore its contribution in mineral waters, and, therefore, an analytical protocol was carefully designed to allow the determination of both anions with this sensor. Results displayed on the label of eight commercial bottles of mineral waters are within the confidence interval of the values obtained with the FIA-sensor system, both for chloride and sulphate. However, results for chloride obtained by titrimetry are, in half of the cases, statistically different from the ones obtained by the sensor, and in 7 out of 8 of them more precise. There is an evidence of a systematic error in the chloride titrimetric analysis, consistent with a small overtaking of the equivalence point. Precision of the results obtained by the titrimetric analysis of sulphate were in 6 out of 8 of the analysis less precise than with the sensor, probably due to losses of the barium sulphate precipitate, which is consistent with the occurrence of lower values. [ABSTRACT FROM AUTHOR]

Abstract The paper focuses on the first attempt at investigating the effect of high-temperature modification with SiO 2 nanoparticles on the diffuse reflectance spectra within 0.2–2.2 μm and on the particle-size distribution of barium sulphate powders. It has been found that there exists the correlation between changes in diffuse reflectance spectra and particle size distribution during heating and modifying BaSO 4 micropowders with SiO 2 nanoparticles. By high-temperature heating (800 °C) of BaSO 4 micropowder and by deposition of SiO 2 nanoparticles (C = 1 wt%), one can increase the reflectance capacity of BaSO 4 powder. Additionally, it is shown that SiO 2 nanoparticles deposited onto the surface block the formation of BaSO 4 micropowder granules. Highlights • Heating BaSO 4 powders at 800 °C increases reflectance in the near IR region. • SiO 2 nanoparticles block the sintering of BaSO 4 powder into granules at T = 800 °C. • Optimal nanoparticle concentration during modifying makes 1 wt%. • Increasing size of BaSO 4 particles leads to decrease in the reflectance coefficient. • Increasing nanoparticle concentration leads to decrease in the BaSO 4 powders reflectance coefficient. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Nanoparticles can act as transporters for synthetic molecules and biomolecules into cells, also in immunology. Antigen-presenting cells like dendritic cells are important targets for immunotherapy in nanomedicine. Therefore, we have used primary murine bone marrow-derived phagocytosing cells (bmPCs), i.e. dendritic cells and macrophages, to study their interaction with spherical barium sulphate particles of different size (40 nm, 420 nm, and 1 µm) and to follow their uptake pathway. Barium sulphate is chemically and biologically inert (no dissolution, no catalytic effects), i.e. we can separate the particle uptake effect from potential biological reactions. The colloidal stabilization of the nanoparticles was achieved by a layer of carboxymethylcellulose (CMC) which is biologically inert and gives the particles a negative zeta potential (i.e. charge). The particles were made fluorescent by conjugating 6-aminofluoresceine to CMC. Their uptake was visualized by flow cytometry, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and correlative light and electron microscopy (CLEM). Barium sulphate particles of all sizes were readily taken up by dendritic cells and even more by macrophages, with the uptake increasing with time and particle concentration. They were mainly localized inside phagosomes, heterophagosomes, and in the case of nanoparticles also in the nearby cytosol. No particles were found in the nucleus. In nanomedicine, inorganic nanoparticles from the nanometer to the micrometer size are therefore well suited as transporters of biomolecules, including antigens, into dendritic cells and macrophages. The presented model system may also serve to describe the aseptic loosening of endoprostheses caused by abrasive wear of inert particles and the subsequent cell reaction, a question which relates to the field of nanotoxicology. Statement of Significance The interaction of particles and cells is at the heart of nanomedicine and nanotoxicology, including abrasive wear from endoprostheses. It also comprises the immunological reaction to different kinds of nanomaterials, triggered by an immune response, e.g. by antigen-presenting cells. However, it is often difficult to separate the particle effect from a chemical or biochemical reaction to particles or their cargo. We show how chemically inert barium sulphate particles with three different sizes (nano, sub-micro, and micro) interact with relevant immune cells (primary dendritic cells and macrophages). Particles of all three sizes are readily taken up into both cell types by phagocytosis, but the uptake by macrophages is significantly more prominent than that by dendritic cells. The cells take up particles until they are virtually stuffed, but without direct adverse effect. The uptake increases with time and particle concentration. Thus, we have an ideal model system to follow particles into and inside cells without the side effect of a chemical particle effect, e.g. by degradation or ion release. [ABSTRACT FROM AUTHOR]