Sulfation Reaction Research Articles

Last piece in the puzzle of bisphenols BPA, BPS and BPF metabolism: Kinetics of the in vitro sulfation reaction.

Bisphenols are endocrine-disrupting chemicals ubiquitously present in the environment, with the consequent exposure to humans. In humans, bisphenols are metabolized to glucuronide and sulfate conjugates. Recent studies indicate that sulfation represents an important bisphenol metabolic pathway for the most vulnerable humans, such as the growing fetus. Our aim was to evaluate sulfation kinetics of commonly detected bisphenols in biological samples: bisphenol A (BPA), bisphenol S (BPS), and bisphenol F (BPF). Furthermore, we evaluated estrogenic agonist potencies and long-term stability of these bisphenol sulfates. BPS and BPF sulfates were prepared by chemical synthesis. Sulfation kinetics of the selected bisphenols were tested in pooled human liver cytosol, as a source for soluble phase II enzymes, including liver sulfotransferases, with quantification by LC-MS/MS. A validated transactivation assay using the hERα-Hela 9903cell line was used to determine estrogenic agonist potencies. Moreover, BPA, BPS, and BPF sulfate stabilities were examined under various conditions and during storage. In vitro sulfation of BPA and BPS followed Michaelis-Menten kinetics; BPF sulfation followed a substrate inhibition model. Sulfation rates were comparable for these bisphenols, although their KM values indicated some large differences in affinities. BPA and BPS sulfates are not hERα agonists. The bisphenol sulfates can be considered stable for at least 2 days under these tested media conditions. These data indicate that bisphenol sulfation is an important route in their biotransformation. Compared to glucuronidation, these bisphenols show slower sulfation rates but similar KM values. BPA and BPS metabolic biotransformation by sulfation provides their detoxification as they are without estrogenic activities.

Synthesis of Sulfated Chitosan Through Sulfation Reaction of Chitosan with Chlorosulfonic Acid in N, N-Dimethylformamide, and Antibacterial Activity Test

Sulfated chitosan has been successfully synthesized through sulfation reaction between chitosan and chlorosulfonic acid using catalyst and N, N-Dimethylformamide (DMF) solvent. The first step was sulfation of chitosan with 4; 4.5; 5 mL of HClSO3. The formation of sulfated chitosan was supported by an increased solubility in water and the appearance of peaks at 1111 cm-1, which indicated the C-O-S group. Sulfated chitosan that has been produced, has a degree of sulfation of 5.6041%; 6.0045%; 6.8051%. Sulfated chitosan shows moderate antibacterial activity and a wide spectrum of antibacterial properties against Escherichia coli and Staphylococcus aureus bacterias. The increase in the degree of sulfation was proportional to the increase in antimicrobial activity of both bacteria. The highest antibacterial activity based on inhibitory zone diameter was 10 mm for sulfated chitosan that has been produced from 1 g of chitosan with 5 mL of HClSO3 with a degree of sulfation was 6.8051%.

Experimental study on the imidazoles of aqueous secondary organic aerosol formed from reaction of methylglyoxal and ammonium sulphate

Imidazole and its derivatives are the main heterocyclic nitrogen-containing brown carbon constituents in aerosol particles. Imidazoles of aqueous secondary organic aerosol (aqSOA) particles formed from the reaction of methylglyoxal and ammonium sulphate ((NH4)2SO4) are detected by vacuum ultraviolet photoionization aerosol mass spectrometer (VUV-PIMS) in real-time and verified off-line with optical spectrometry in current study. The experimental results showed that the single photon ionization mass spectrum of aqSOA particles measured by VUV-PIMS emerged the molecular ion peaks at m/z = 68, 82 and 110. While, the extraction solution of aqSOA particles detected by off-line techniques demonstrated that the characteristic peaks at 217 and 282 nm appeared in the UV–Vis spectrum; the strong emission in 405–480 nm with maximum emission wavelength at 435 nm contained in the 3D fluorescence spectra; and the chemical shift peaks of hydrogen atoms on N–H, CC and CN bond on imidazole ring and methyl group arised in the 1H-NMR spectrum. In view of these spectral information, 4-methyl-imidazole and 4-methyl-imidazole-2-carbaldehyde are determined as the principal products of the aqueous reaction between methylglyoxal and (NH4)2SO4. The possible reaction mechanism leading to the generation of imidazole compounds are also discussed. These will help to understand the formation process of imidazole compounds in atmospheric aerosol particles, and provide experimental basis for the model mechanism study of aqSOA particles.

Calcination and desulfurization characteristics of calcium carbonate in pressurized oxy-combustion

Pressurized oxy-combustion is one of the most promising and efficient CO2 capture technologies for coal-fired power plants, which could reduce energy consumption for carbon capture. However, due to the effects of pressurization and flue gas recirculation, the partial pressure of sulfur oxides (SOx) in pressurized oxy-combustion is significantly higher than that of air-combustion, which leads to the corrosion risks and environment hazards. It is essential to investigate the SOx control in pressurized oxy-combustion. In this paper, the in-furnace calcination and desulfurization characteristics of calcium carbonate in pressurized oxy-combustion were carried out in a pressurized drop tube furnace. The findings show that the sulfation reaction in pressurized oxy-combustion is direct sulfation and the sulfation rate increases with the increase of temperature and pressure. The desulfurization efficiency in pressurized oxy-combustion is lower than that in atmospheric air atmosphere below 950 °C, but it reverses above 950 °C, indicating that the minimum desulfurization temperature in the furnace of the pressurized oxy-combustion is higher than that of atmospheric air atmosphere. Therefore, limestone can still be used as a sorbent in the pressurized oxy-combustion furnace. This study could contribute to the design of dry desulfurization systems in pressurized oxy-combustion combustors that use fossil fuel energies with high efficiency and low SOx emissions.

Development of 3α,7α-dihydroxy-6α-ethyl-24-nor-5β-cholan-23-sulfate sodium salt (INT-767): Process optimization, synthesis and characterization of metabolites

Herein we report our synthetic efforts in supporting the development of the bile alcohol sulfate INT-767, a FXR/TGR5 dual agonist with remarkable therapeutic potential for liver disorders. We describe the process development to a final route for large scale preparation and analogues synthesis. Key sequences include Grignard addition, a one-pot two-step shortening-reduction of the carboxylic side chain, and the final sulfation reaction. The necessity for additional steps such as the protection/deprotection of hydroxyl groups at the steroidal body was also evaluated for step-economy and formation of side-products. Critical bottlenecks such as the side chain degradation have been tackled using flow technology before scaling-up individual steps. The final synthetic route may be successfully employed to produce the amount of INT-767 required to support late-stage clinical development of the compound. Furthermore, potential metabolites have been synthesized, characterized and evaluated for their ability to modulate FXR and TGR5 receptors providing key reference standards for future drug investigations, as well as offering further insights into the structure-activity relationships of this class of compounds.

Crystallization kinetics of large-sized columnar α-hemihydrate gypsum by reaction of waste CaCl2 and Al2(SO4)3 without crystal modifiers

Direct production of high-strength α-calcium sulfate hemihydrate (α-HH) with no additives was accomplished by the reaction of aluminum sulfate and waste CaCl2 discarded from Solvay soda plant. For scaling-up this new process, the crystallization kinetics of α-HH was experimentally investigated under varying conditions including temperature (323–363 K), concentration of CaCl2 (4–7 mol/kg), Al2(SO4)3 (0.6–3.0 mol/kg), and seed loading. The optimal operating conditions are 7 mol/kg CaCl2 solution, 0.8 mol/kg Al2(SO4)3 solution, 5 wt% seed loading, 2 mol/kg AlCl3 existing in the reactor, T = 353 K, and equilibrium time of 3 h. The α-HH with large columnar shape, as desired in industry, was successfully obtained at optimal conditions by use of a continuous stirred tank reactor (CSTR) without the addition of any additives. The stability test of various CaSO4 phases in aqueous AlCl3, CaCl2, and their solution mixtures elucidated that Al3+ ion and total concentration of Cl− ion play an important role in the growth and shape of α-HH crystal.

Silver-manganese nanocomposite modified screen-printed carbon electrode in the fabrication of an electrochemical, disposable biosensor strip for cystic fibrosis.

A silver-manganese nanocomposite was successfully prepared by the urea hydrolysis method and used to detect chloride ions in sweat electrochemically. The synthesis involves the reaction of manganese sulphate, silver nitrate, and urea at 100°C for 24h. The crystalline nature of the particle was studied by diffraction analysis and found to be mixed-phase oxides of manganese alongside the oxides of silver. Morphological studies revealed the presence of quasi-prism-like structures, which is characteristic of β-MnO2. A disposable sensor was fabricated by screen-printing the catalyst and used for the electrochemical detection of chloride ions in sweat. The sensor exhibited good selectivity, a sensitivity of 22.93 ± 0.64µAmM-1cm-2 in solution and 3010 ± 60µA(log mM) -1cm-2for the fabricated sensor strip with a detection range from 5mM up to 200mM. The detection limit is 207 ± 7µM (S/N = 3) in solution and 17 ± 6µM for the fabricated sensor strip. The relative standard deviation (RSD) of sensor response is 2.38%. A prototype of the biosensor strip was fabricated and validated using real samples. This brings the possibility of developing a real-time biosensor strip for cystic fibrosis in point-of-care testing applications.

Insights into the reaction of chondroitin sulfate with glycidyl methacrylate: 1D and 2D NMR investigation

Chondroitin sulfate methacrylate (CS-MA) is a semisynthetic biopolymer increasingly used for the fabrication of chemical hydrogels. In this study, the methacrylation reaction of native CS was carried out with glycidyl methacrylate in dimethyl sulfoxide and optimized to obtain tunable and reproducible methacrylation degrees in a short reaction time. The methacrylation reaction was deeply characterized by mono- and bi-dimensional (1D, 2D) NMR spectroscopy of CS-MA derivatives with different methacrylation degrees. In contrast to what previously reported in the literature, HSQC, HMBC and TOCSY analyses revealed that the methacrylation reaction proceeds via both epoxy ring-opening and transesterification, involving predominantly the primary hydroxyl groups of CS, while preserving sulfate and carboxyl groups of the biopolymer. These findings are of fundamental importance for appropriate and rational design of CS-MA-based biomaterials.

Triassic multistage antimony-gold mineralization in the Precambrian sedimentary rocks of South China: Insights from structural analysis, paragenesis, 40Ar/39Ar age, in-situ S-Pb isotope and trace elements of the Longwangjiang-Jiangdongwan orefield, Xuefengshan Mountain

The Xiangzhong (XZ) Basin and its neighboring Xuefengshan (XFS) Mountain in South China, as one of the world-class antimony (Sb) producers, have provided appropriately 67% of globally exploited Sb metal (0.46 million tons) in human history. The associated gold (Au) with Sb in this region is also of significant economic values. In previous studies, these Sb-Au deposits were debated as a diversity of genetic types such as epithermal, magmatic-hydrothermal, sedimentary exhalative (SEDEX) and orogenic Sb-Au deposits. To evaluate these genesis hypotheses, we select the representative Longwangjiang-Jiangdongwan (LWJ-JDW) orefield to reveal the Sb-Au accumulation process and metal-fluid sources of these deposits. Our orefield-scale structural analysis shows that the localization of principal Sb-Au orebodies is controlled by a NE-striking sinistral shearing system composed by an integrated set of NE-striking and SE-dipping fractures in the pre-ore folded Neoproterozoic Wuqiangxi slate. Two chief ore periods were identified, including the marine sedimentation (SI, pyrite nodular) and tectonic-metamorphic hydrothermal period (SⅡ−SⅣ, Sb-Au veins). The second period is further subdivided into three stages of SⅡ (pre-tectonic deformed pyrite-milky quartz veins), Siii (syn-tectonic pyrite-arsenopyrite-stibnite-quartz veins) and SⅣ (post-tectonic stibnite-calcite veinlets). It is notable that gold precipitation is significantly prior to Sb ores at LWJ-JDW. Three sericite samples throughout SⅡ−SⅣ yield a group of well-defined 40Ar/39Ar plateau ages (253 ± 4, 234 ± 3 and 206 ± 2 Ma, respectively). This indicates the multistage Sb-Au mineralization initiated from Early Triassic and terminated at Late Triassic time. Further trace elements analyses show the earliest nodular PyI is enriched in a list of As, Ni, Sb, Cu, Se, Co, Pb, Zn and Ti that can be analogy to the diagenetic pyrite in the organic-rich marine sedimentary rocks. Extremely high Sb (median, 1107 ppm) and mediate Au (0.07 ppm) are monitored in PyI, indicative of the initial Sb and Au involvement from the Neoproterozoic sedimentation. Comparably, sulfides of the later SⅡ−SⅣ possess a similar spectrum of trace elements but with highly variable concentrations. All the sulfide generations host the wide range of in-situ δ34SV-CDT values (–23.9 to −3.7‰ for SⅠ, −7.6 to −2.9‰ for SⅡ−SⅣ, respectively), indicating sulfur originally sourced from bacterial sulfate reaction (BSR) of the Neoproterozoic seawater sulfates, and then gradually reduced by thermochemical sulfate reaction (TSR) during the subsequent Au-Sb-induced tectonic-metamorphic hydrothermal activity. The lead isotope compositions in accordance with the evolution lines of upper crust and orogen, implying that the Pb were chiefly sourced from host slate of the Wuqiangxi Formation and its underlying basement. Synthesis of these data, we proposed that the Sb-Au accumulation at LWJ-JDW was caused by the multistage mineralization from Neoproterozoic marine sedimentation to Triassic episodic deformation and metamorphic processes (253–206 Ma).

Copper-catalyzed multicomponent reactions for the efficient synthesis of diverse spirotetrahydrocarbazoles.

In the presence of copper sulfate, three- or four-component reactions of 2-methylindole, aromatic aldehydes and various cyclic dienophiles in refluxing toluene afforded diverse spirotetrahydrocarbazoles. This reaction is an important development of the Levy reaction by using 2-methylindole to replace ethyl indole-2-acetate and successfully provides facile access to important polysubstituted spiro[carbazole-3,3'-indolines], spiro[carbazole-2,3'-indolines], spiro[carbazole-3,5'-pyrimidines] and spiro[carbazole-3,1'-cycloalkanes] in satisfactory yields and with high diastereoselectivity.

Integrated Kinetic Modelling and Microbial Profiling Provide Insights Into Biological Sulfate-Reducing Reactor Design and Operation.

Biological sulfate reduction (BSR) is an attractive approach for the bioremediation of sulfate-rich wastewater streams. Many sulfate-reducing microorganisms (SRM), which facilitate this process, have been well-studied in pure culture. However, the role of individual members of microbial communities within BSR bioreactors remains understudied. In this study we investigated the performance of two up-flow anaerobic packed bed reactors (UAPBRs) supplemented primarily with acetate and with lactate, respectively, during a hydraulic retention time (HRT) study set up to remediate sulfate-rich synthetic wastewater over the course of 1,000 + days. Plug-flow hydrodynamics led to a continuum of changing volumetric sulfate reduction rates (VSRRs), available electron donors, degrees of biomass retention and compositions of microbial communities throughout these reactors. Microbial communities throughout the successive zones of the reactors were resolved using 16S rRNA gene amplicon sequencing which allowed the association of features of performance with discrete microorganisms. The acetate UAPBR achieved a maximum VSRR of 23.2 mg.L−1. h−1 at a one-day HRT and a maximum sulfate conversion of the 1 g/L sulfate of 96% at a four-day HRT. The sulfate reduction reactions in this reactor could be described with a reaction order of 2.9, an important observation for optimisation and future scale-up. The lactate UAPBR achieved a 96% sulfate conversion at one-day HRT, corresponding with a VSRR of 40.1 mg.L−1. h−1. Lactate was supplied in this reactor at relatively low concentrations necessitating the subsequent use of propionate and acetate, by-products of lactate fermentation with acetate also a by-product of incomplete lactate oxidation, to achieve competitive performance. The consumption of these electron donors could be associated with specific SRM localised within biofilms of discrete zones. The sulfate reduction rates in the lactate UAPBR could be modelled as first-order reactions, indicating effective rates were conferred by these propionate- and acetate-oxidising SRM. Our results demonstrate how acetate, a low-cost substrate, can be used effectively despite low associated SRM growth rates, and that lactate, a more expensive substrate, can be used sparingly to achieve high VSRR and sulfate conversions. We further identified the preferred environment of additional microorganisms to inform how these microorganisms could be enriched or diminished in BSR reactors.

Rare Earth Magnets and Limescale: Analysis of Magnetic Water Treatment Using a Dynamic Scale Rig

Treatment of limescale build-up in process- and municipal pipes by magnetic water treatment has been a topic of research for decades. However, there is no realistic mechanistic hypothesis as to why such treatments would be effective. Therefore, a test regime was established to explore scale inhibition by means of magnetic forces in a robust and reproducible manner. In this study, two magnetic devices were developed using Neodymium-based rare earth magnets for the application of static magnetic fields. One device, based on a Halbach array, is designed to test high-intensity (965 mT) magnetic fields. The other is based on a Halbach trap arrangement, designed to test high magnetic field gradients (490 mT, 82.5 T/m). The precipitation reactions of calcium carbonate, calcium sulfate, and calcium phosphate were monitored in real-time to determine the effectiveness of these devices for inhibiting scale. No magnetic treatment effects were observed.

Modeling the Process and Properties of Ash Formation during Pulverized Biomass Combustion

The present work mainly developed a mathematical model based on the plug flow model and coarse fly ash particles’ fragmentation model to describe the behavior and evolution of ash formation and the influence of the biomass feeding rate and flue gas cooling rate on ash properties, which is validated by literature data. The model considers homogeneous nucleation of alkali vapors, heterogeneous condensation of vapors on newly formed particles and fly ash particles, and collision-coagulation between aerosol particles, which is also applied to numerically study and analyze the ash formation characteristics in the cases of practical boiler pulverized fuel combustion and SO2 sulfation. The results show that the mathematical model can reasonably describe the ash formation and the influence of the biomass feeding rate and the flue gas cooling rate on the mass PSDs of PM10 and its elements. The initial nucleation temperature and initial nucleation particle size increase with the biomass feeding rate, which is of great importance to the cooling rate on the initial nucleation number concentration and the initial nucleation particle size. Elements Na, K, and Cl are mainly concentrated in PM1, but rarely distributed in PM1–10. The condensation of Na, K, and Cl on coarse particles increases with the biomass feeding rate and decreases with the cooling rate. The ash characteristics obtained from the experiment condition with an ultra-high flue gas cooling rate and minimum biomass selected may have a large deviation from that of practical biomass combustion, and the sulfated reaction may reduce Cl corrosion rather than ash deposition.

Properties of Rubberized Concrete Prepared from Different Cement Types

At present, global waste tire generation considerably exceeds consumption. Moreover, waste rubber tires (WRTs) are a cause of concern, as huge volumes are being discarded and buried, thus causing serious environmental pollution. Rubberized waste concrete (RWC) is a type of environmentally friendly construction material. The main challenge encountered when manufacturing rubberized concrete is the low adhesive properties between the cement paste and rubber particles. This paper demonstrates the effects, through experiments, of using waste tire rubber instead of recycled coarse aggregate (RCA) on two types of cement, i.e., sulfate-resistant cement (SRC) and ordinary Portland cement (OPC), where SRC is a specially blended cement designed to improve concrete performance and workability in the most aggressive environments. All tested samples contained 10% silica fume (SF) and 0.2% fly ash (FA), and the substitution of recycled aggregate content with waste rubber tier (WRT) at different percentages of 100%, 75%, and 50% was evaluated. The research investigated the synergistic effect on the workability and mechanical properties of various cement types with different amounts of rubber aggregate. It was found that the sulfate-resistant (SRC) type can increase the compressive strength than OPC with a percentage of 25% with the same content of WRT at concrete mix. Moreover, ductility and cracking behavior are improved, and it appears that it is also possible to make lightweight rubber aggregate concrete with this type of mixture.. Using this type of cement, it is possible to restore satisfactory ductility to the waste tires, thus facilitating a reduction in the formation of potential plastic cracks. Moreover, the indicative compressive strength development for SRC with recycled rubber in concrete positively contributes to a reduction in formed cracks. However, SEM microstructural analyses suggest a higher proportion of C–S–H intermixed with sulfate reaction phases of SRC rubberized mortar than those of OPC; thus, given that crystal growth results in a decreased percentage of air voids rather than decreased internal cracking, it is clearly shown that the average crack width increases in OPC mortar compared with SRC. Finally, t-testing was used as an inferential statistical tool to determine whether there is a sizeable distinction between the properties of the two categories of materials, OPC and SRC, by comparing the mean and standard deviation of the values for compressive and tensile strength.

STUDY ON SOME DURABILITY PROPERTIES OF HIGH-STRENGTH FINE-GRAINED CONCRETE USING SALINE SAND AND CRUSHED AGGREGATE

This paper presents the results of research on some durability properties of high-strength fine-grained concrete made from saline sand and crushed aggregates with different mixing ratios. The specific mechanical properties and durability of concrete when working in a saline environment were tested, including compressive strength, water absorption, sulfate durability, and the alkali-aggregate reaction of concrete. The results show that: when replacing regular aggregate in C50 concrete with a mixture of salted sand and crushed aggregate with an appropriate mixing ratio, the concrete has a compressive strength of over 50 MPa, and water absorption reduces significantly. The sulfate and alkali-aggregate reaction are guaranteed to meet the requirements set forth by the standards for sulfate and alkali-resistant durability concrete. This result has great significance in the study and application of high-strength fine-grained concrete made from saline sand to build the constructions in marine and island environments.

The influence of alkyl substitution on the in vitro metabolism and mutagenicity of benzo[a]pyrene

In recent years concerns over consumer exposure to mineral oil aromatic hydrocarbons (MOAH), especially those containing alkylated polycyclic aromatic hydrocarbons (PAHs), have emerged. This is especially due to the fact that some PAHs are known to be genotoxic and carcinogenic upon metabolic activation. However, available toxicological data on PAHs mainly relate to non-substituted PAHs with limited data on alkyl substituted PAHs. Therefore, the aim of the present study was to characterize in more detail the effect of alkyl substitution on the metabolism and mutagenicity of benzo[a]pyrene (B[a]P), a PAH known to be genotoxic and carcinogenic. To this end, the oxidative metabolism and mutagenicity of B[a]P and a series of its alkyl substituted analogues were quantified using in vitro microsomal incubations and the Ames test. The results obtained reveal that upon alkylation the metabolic oxidation shifts to the aliphatic side chain at the expense of aromatic ring oxidation. The overall metabolism, including metabolism via aromatic ring oxidation resulting potentially in bioactivation, was substantially reduced with elongation of the alkyl side chain, with metabolism of B[a]P with an alkyl substituent of >6 C atoms being seriously hampered. In the Ames test upon metabolic activation, the methyl substitution of B[a]P resulted in an increase or decrease of the mutagenic potency depending on the substitution position. The relevant pathways for mutagenicity of the selected monomethyl substituted B[a]P may involve the formation of a 7,8-dihydrodiol-9,10-epoxide, a 4,5-oxide and/or a benzylic alcohol as an oxidative side chain metabolite which subsequently may give rise to an unstable and reactive sulfate ester conjugate. It is concluded that alkylation of B[a]P does not systematically reduce its mutagenicity in spite of the metabolic shift from aromatic to side chain oxidation.

EFFECT OF ADDITIONAL TRISODIUM PHOSPHATE 2% AS A RETARDER TO DIMENSIONAL STABILITY TESTS DENTAL MATERIAL ALGINATE AFTER HARDENING

The alginate moulding material is a negative mold of the teeth and oral cavity tissue. The alginate molding material is hydrophilic and is used as a pre-elimination mold to a custom tray for a more accurate second mold. The dimensional stability of the alginate mold is essential for the success of making a precise mold model. Changes in alginate dimensions are related to the contraction during the hardening process of the alginate molding material or the setting time. The addition of Trisodium Phosphate (TSP) is known to prolong the hardening time of alginates by slowing down the reaction of alginate salts and calcium sulfate. The purpose of this study was to compare the dimensional stability test of the alginate molding material with the addition of 2% trisodium phosphate and those without 2% trisodium phosphate after hardening. This research is pure laboratory experimental research. Alginate was divided into two groups: the group according to the manufacturer's provisions and the group added with 2% trisodium phosphate. The results of this study were analyzed using the unpaired T-test, and the results showed a p-value <0.05, namely (0.00 <0.05), so there was a significant difference in the dimensional stability of alginate without TSP 2% with the addition of TSP 2%. This study showed that the addition of 2% TSP improved dimensional stability in the group with the addition of 2% TSP.

Improvement in Durability and Mechanical Performance of Concrete Exposed to Aggressive Environments by Using Polymer.

Concrete is the most widely used construction material. However, it cannot sustain the harsh environment and can easily deteriorate. It results in repair and reworks that amount to a considerable loss of money and time. The life span of concrete reduces if exposed to external attacks, for instance, sulfate attacks, alkali-silica reactions, corrosion, and drying shrinkage. These ubiquitous attacks cause a reduction in service life and raise the need for early repair and maintenance, resulting in higher life cycle costs and structural failures. To resolve these issues, the potential of styrene-butadiene-rubber (SBR) ultrafine powder as cement replacement polymeric admixture at 0%, 3%, 5%, 7%, and 10% have been evaluated. The effect of SBR-powder on concrete is investigated by conducting an alkali-silica reactivity test (ASR), rapid-chloride-permeability test (RCPT), drying shrinkage, and sulfate resistivity tests. Workability, compressive and flexural strength tests are also conducted. For ASR and drying shrinkage, mortar bar samples were cast, exposed to respective environments, and the percentage change in length was measured. For mechanical tests and RCPT, prisms, cylinders and cubes were cast and tested at 28 days. The SBR-powder modification reduces concrete’s permeability, drying shrinkage, and expansions due to ASR and sulfate attacks. SBR powder increased workability by 90%, compressive strength by 23%, and flexural strength by 9.4% in concrete when used at 10% cement replacement by weight. The SBR-powder (10%) modification reduced the RCPT value by up to one-third (67%), drying shrinkage by 53%, ASR by 57%, and sulfate reaction by 73%. Consequently, SBR powder usage can adequately improve the workability, mechanical properties, and durability of the concrete and lead to advanced sustainable concrete with low repair requirements.

Sulfated Phenolic Substances: Preparation and Optimized HPLC Analysis.

Sulfation is an important reaction in nature, and sulfated phenolic compounds are of interest as standards of mammalian phase II metabolites or pro-drugs. Such standards can be prepared using chemoenzymatic methods with aryl sulfotransferases. The aim of the present work was to obtain a large library of sulfated phenols, phenolic acids, flavonoids, and flavonolignans and optimize their HPLC (high performance liquid chromatography) analysis. Four new sulfates of 2,3,4-trihydroxybenzoic acid, catechol, 4-methylcatechol, and phloroglucinol were prepared and fully characterized using MS (mass spectrometry), 1H, and 13C NMR. The separation was investigated using HPLC with PDA (photodiode-array) detection and a total of 38 standards of phenolics and their sulfates. Different stationary (monolithic C18, C18 Polar, pentafluorophenyl, ZICpHILIC) and mobile phases with or without ammonium acetate buffer were compared. The separation results were strongly dependent on the pH and buffer capacity of the mobile phase. The developed robust HPLC method is suitable for the separation of enzymatic sulfation reaction mixtures of flavonoids, flavonolignans, 2,3-dehydroflavonolignans, phenolic acids, and phenols with PDA detection. Moreover, the method is directly applicable in conjunction with mass detection due to the low flow rate and the absence of phosphate buffer and/or ion-pairing reagents in the mobile phase.

Efficacy of nebulized magnesium sulfate in moderate bronchiolitis

Background: Bronchiolitis is a common cause of illness and hospitalization in infants and young children. The effectiveness of various bronchodilators remains unclear. This study was conducted to assess the efficacy of nebulized magnesium sulfate in hospitalized children with moderate bronchiolitis in the age group of 1–24 months. Subjects and Methods: This was a prospective observational study done from December 2018 to June 2020. All children with moderate bronchiolitis (clinical severity score [CSS]-4–8) meeting inclusion/exclusion criteria were enrolled. A detailed history, demographic profile, CSS and oxygen saturation in room air, and heart rate were recorded. They were given two doses of magnesium sulfate in the form of nebulization for 10 min each, at 30 min apart. The children were assessed for CSS at 0 h, 1 h, and 4 h after nebulization. The children were considered improved if CSS <4 at the end of 4 h. The children were monitored for adverse reactions of magnesium sulfate. Results: Sixty children were enrolled. The mean age was 7.5 ± 6.47 months. Most children (51.7%) were in 1–6 months. The mean CSS scores at 0 h, 1 h, and 4 h were 6 ± 1.008, 2.95 ± 1.395, and 2.40 ± 1.564, respectively (P = < 0.001). Fifty-three (88.3%) children improved and seven (11.7%) children did not improve. In nonimproved group, subanalysis was done and found hypoxia (odds ratio − 12.6) as a significant risk factor. Flushing was the most common adverse effect noticed in eight (13.3%) children. Conclusions: Children with moderate bronchiolitis were improved with nebulized magnesium sulfate.