Amine Concentration Research Articles

Enhancing CO2 capture in cement-based materials with alkanolamines: A comprehensive study on efficiency, phase-specific impact, and carbonation mechanisms

The escalating issue of global warming, driven by the surge in CO2 emissions, necessitates innovative strategies for reducing CO2 emissions. A novel approach is explored in this study, where amines featuring a basic N atom with a lone pair are incorporated into cement paste to facilitate CO2 capture from the environment. Unlike conventional applications, the focus is on the collaborative effect of various amines on CO2 capture within diverse calcium-rich phases, encompassing portlandite and Calcium-Silicate-Hydrate (C-S-H). This investigation seeks to discern the most efficient amine and optimal concentration for CO2 capture, particularly within distinct phases of cement paste. Notably, 2-(methylamino) ethanol (MAE) demonstrates superior performance in promoting CO₂ mineralisation and has been selected to further evaluate its ability in cement paste under natural carbonation conditions. Importantly, this research presents an exhaustive analysis of C-S-H carbonation with varying Ca/Si ratios, revealing carbonation mechanisms and consequential microstructural alterations in the presence of amine. Additionally, the presence of amine significantly influences crystal growth and the polymerisation of C-S-H. Furthermore, natural carbonation experiments underscore the efficacy of MAE, showcasing a 2.5-fold increase in calcite formation in the cement paste compared to scenarios without MAE.

Unraveling the unique microbiota and metabolites in three different colors Jiangqu through multidimensional analysis

Tri-colored Jiangqu, including white (WQ), yellow (YQ), and black (BQ)-color Daqu, significantly influence fresh Baijiu yield and quality. The differences in attributes of these Jiangqu types, sourced from two renowned Baijiu enterprises, were investigated using multi-omics approaches. Color intensity negatively correlated with ammonia nitrogen content, but positively with pyroglutamic acid content. 182 volatiles and 291 non-volatiles were identified, with each types exhibiting unique metabolites. Esters, pyrazines, ketones and phenols were predominant in WQ, YQ, and BQ, respectively. The content of peptides, amines, and amino acids with derivatives also showcased the differences of microbiota and metabolic pathways among tri-colored Jiangqu. BQ's characteristic components of L-Tyrosine and acetyl tributyl citrate were closely associated with melanin formation. In YQ, Scopulibacillus and Rhizopus correlated positively with tetramethylpyrazine. Moreover, the bacterial community significantly influenced the metabolic profiles, and synergistic interactions between fungal and bacterial communities were crucial in determining metabolite abundance.

Multivalent Amine Functionalized Carbon Dots Catalyze Efficient Denitrosylation

Nitric oxide (NO) is an essential signaling molecule with several biological functions and holds great promise in biomedical applications. However, NO delivery strategies have been challenged with its inherent short half‐life and limited transport distance in human tissues. Strategies focused on the catalytic production of NO at the target site would afford an effective biomaterial. Herein, we introduce a carbon nanodot (CD) platform featuring multivalent amine groups that catalyze the denitrosylation from S‐nitrosothiols. In the present study, we have developed a novel multivalent amine functionalized carbon dots to catalytically transform endogenous prodrugs S‐nitrosothiols to generate NO at physiological conditions. The mechanism of NO generation follows nucleophilic attack of the surface primary amine groups on the electrophilic thiol group of S‐nitrosothiols, which is supported by various control studies and electron paramagnetic resonance (EPR). Notably, the release of NO is easily tuned by the prodrug concentration and surface density of amines on the CDs. Significantly, the NO releasing feature of CDs is integrated with prototissue module to evaluate the NO release profile in the biological environment. This study will deepen our understanding in designing useful multivalent systems to generate NO from endogenous prodrugs to realize their therapeutic potential.

Real-Time Estimation of CO2 Absorption Capacity Using Ionic Conductivity of Protonated Di-Methyl-Ethanolamine (DMEA) and Electrical Conductivity in Low-Concentration DMEA Aqueous Solutions

The present study investigates the real-time estimation of CO2 absorption capacity (CAC) based on the electrical conductivity (EC) of low-concentration di-methyl-ethanolamine (DMEA) solutions (0.1–0.5 M). CO2 absorption experiments are conducted to measure the variation in CAC and EC during CO2 absorption, revealing a strong correlation between the two properties. The ionic conductivity of DMEAH+ formed during absorption is calculated to be 53.1 S·cm2/(mol·z), which is found to be larger than that of TEAH+ and MDEAH+. This can be attributed to the smaller molar mass and higher ionic mobility of DMEAH+. A significant finding is that the measured EC (ECM) of the DMEA solutions consistently demonstrates a lower value than the theoretically predicted value. This discrepancy is due to the larger ionic size of DMEAH+, which results in a reduction in the real mean ionic activity coefficient. This effect becomes more pronounced with increasing DMEA concentration. Consequently, a higher CAC is required to produce the same change in EC at higher amine concentrations. Based on these findings, an empirical equation is devised to estimate CAC from ECM in solutions of constant DMEA concentration. This equation will be employed as a practical approach for the in situ monitoring of CO2 absorption using DMEA aqueous solution.

Parameters of Collision and Adhesion Process Between a Rising Bubble and Quartz in Long-Chain Amine Solution and Their Correlation with Flotation

The successful adhesion of air bubbles to mineral particles is the crucial to flotation technology. This paper systematically investigates the parameters variation in the dynamic interaction process between a rising bubble and a quartz plate in long-chain amine solutions (dodecylamine, tedecylamine, and octadecylamine). The results show that the type and concentration of long-chain amine affected the collision and adhesion process between bubbles and quartz plates remarkably. The maximum rebound distance (rebound distance after the first collision) of bubbles and the stable-state liquid film thickness gradually decreases with the increase of reagent concentration. Additionally, the collision-rebound duration and induction time shorten accordingly, the surface tension of the solution decreases, the surface hydrophobicity of quartz increases, and the deformation degree and average movement velocity of bubbles decrease. With the increase in carbon chain length, the adsorption form of the amine collector and quartz surface becomes closer to vertical, and the density of water molecules decreases. The recovery of quartz particles is highest with octadecylamine systems, corresponding well with the changing trend in steady-state liquid film thickness. This research provides an effective method for in-depth analysis of the microscopic interaction mechanism between bubbles and mineral surfaces and the prediction of flotation results.

Correlation Analysis of Subjective and Objective Texture Properties: Color and Heterocyclic Amine Content of Grilled Chicken Breast Fillet

The present study discusses the technofunctional properties (color, texture) of grilled chicken with both objective (colorimeter, texture profile) analysis and subjective (sensory) analysis. Besides them, the total content of potentially carcinogenic heterocyclic amines (HCAs) was also monitored by the applied grilling time–temperature combinations. The same samples were analyzed during the heat treatment of chicken breast samples for 5–15 min at 150–230 °C on an electric contact grill. The grilling variables included the effect of skin cover. Among the structural parameters, hardness exhibited a significant difference between the groups of skin-covered and not-covered ones, and in this case, a linear connection was also found with the time and temperature values, respectively. The structural parameters obtained by sensory and instrumental analysis were compared to each other. In addition, the structural parameters were compared to the color ones (sensory, color according to the CIELAB system: brightness, redness, and yellowness) and to the total HCA content. In the case of closed grilling, sensory-evaluated parameters such as juiciness and tenderness showed a strong negative correlation to instrumentally measured hardness (R = −0.879; −0.749) and chewiness (R = −0.872; −0.718) due to the water loss from the increase in grilling temperature and time. The total HCA content positively correlated to chewiness (R = 0.789). The sensory color parameter and the brightness had a strong connection with juiciness (R = 0.738; 0.723), hardness (R = −0.795; −0.706), and chewiness (R = −0.843; −0.818); redness showed positive correlation to cohesiveness (R = 0.764) and chewiness (R = 0.829). Accordingly, juiciness and chewiness showed a connection to the total HCA levels, which makes it possible to carry out further research on instrumental and sensory parameters that may predict the formation of hazardous amounts of carcinogenic heterocyclic amines.

Influence of processing factors on quality and heterocyclic amines content in roast mutton granules

Using the best conditions of QuEChERS with superior performance, 7 kinds of HAAs were quickly extracted from roasted mutton granules. Subsequently, the effects of different roasting time, temperature and oil on quality, fatty acid, precursor substance and HAAs content of roasted mutton granules were studied. The results showed that with the increase of roasting temperature and time, the hardness, chewability, b* and L* were significantly decreased, while the a* and cohesiveness were significantly increased (P < 0.05). With the extension of roast time, creatine content first increased and then significantly decreased (P < 0.05), which was converted to creatinine. Creatine increased with the increase of processing temperature, creatinine showed an overall downward trend, and glucose content significantly decreased, and then stabilized at a lower level with the extension of roasting time. The glucose content of rapeseed oil was the highest and soybean oil was the lowest. Soybean oil samples had the highest creatine content and the corresponding creatinine content was also the lowest. HAAs also showed an increasing trend with the increase of roasting time and temperature, and five vegetable oils to some extent inhibit the formation of HAAs in actual foods (except PhIP). The maximum inhibition rates for Norharman, Harman, IQ, MeIQ, MeIQx and AαC were 12.06 %, 23.93 %, 142.13 %, 18.75 %, 16.58 % and 53.98 %, respectively.

Biogenic Amine Content and Shelf-Life of Salmon Fillets Packaged in Modified Atmospheres of Low-Level Carbon Monoxide and Different Carbon Dioxide Concentrations

Biogenic Amine Content and Shelf-Life of Salmon Fillets Packaged in Modified Atmospheres of Low-Level Carbon Monoxide and Different Carbon Dioxide Concentrations

Preparation and characterization of uniform polyurea microspheres via an environmental-friendly synthetic process: The swelling and shrinkage phenomena

In this work, a non-toxic isocyanate HDB-LV is used for the first time to produce monodispersed polyurea microspheres with a size from 10 to 40μm via a microfluidic droplet approach. The toxic ethylenediamine which is usually necessary for the synthesis of polyurea, is found to be not adaptable for the formation of polyurea microspheres because it can either cause swelling (at low amine concentration) or deformation (at high amine concentration) of the microspheres. A theoretical mechanism for the swelling phenomenon of microspheres is elucidated. Alternatively, thermal hydrolysis of isocyanates that can generate amines is proven to be very effective for the synthesis of polyurea microspheres. A linear relationship between the sizes of microfluidic droplets and polyurea microspheres is found and discussed quantitatively. In the end, the polyurea microspheres from 2 to 40μm are characterized to have no obvious scattering effects against UV.

Enhancing zein functionality through sequential limited Alcalase hydrolysis and transglutaminase treatment: Structural changes and functional properties

This study investigated the effects of sequential enzymatic hydrolysis using Alcalase, followed by transglutaminase conjugation on the secondary and tertiary structures, hydrophobicity, free amine content, protein-protein interactions, and functional properties of zein. Fourier-transform infrared spectroscopy showed that the most significant secondary structural changes, characterized by a decrease in α-helix content and an increase in β-turns, occurred at a higher degree of hydrolysis. At a 2 % degree of hydrolysis, it revealed notable emulsifying activity (65.96 m2/g), while at 5 % hydrolysis, it achieved the highest solubility (75.06 %). Additionally, the zein hydrolysate with a 7 % hydrolysis degree, treated with transglutaminase, demonstrated improved H0 values (2992.33), enhanced foam capacity (65.95 %), and increased solubilized protein content in a dithiothreitol extractant (31.35 %). Meanwhile, native zein treated with transglutaminase showed the highest water holding capacity (4.47 g/g). Overall, the combined enzymatic approach modified zein structure and properties, suggesting potential for improving functionality in plant-based food applications.

Comprehensive Safety Assessment of Lacticaseibacillus paracasei subsp. paracasei NTU 101 Through Integrated Genotypic and Phenotypic Analysis.

Probiotics, as defined by the World Health Organization, are live microorganisms that, when consumed in sufficient quantities, provide health benefits to the host. Although some countries have approved specific probiotic species for use in food, safety concerns may still arise with individual strains. Lacticaseibacillus paracasei subsp. paracasei NTU 101 (NTU 101), isolated from the gut of healthy infants, has demonstrated various probiotic effects and shown safety in a prior 28-day animal feeding study. To further verify its safety and mitigate potential risks, we performed a comprehensive genotypic and phenotypic safety evaluation in accordance with the European Food Safety Authority guidelines for safety assessment through whole genome sequencing and related literature. In this research, minimum inhibitory concentration testing identified NTU 101's resistance to chloramphenicol; however, subsequent gene analysis confirmed no associated risk of resistance. Assessments of safety, including biogenic amine content, hemolytic activity, mucin degradation, and D-lactic acid production, indicated a low level of risk. Additionally, a repeated-dose 90-day oral toxicity study in Sprague-Dawley rats revealed no toxicity at a dose of 2000 mg/kg body weight, further supporting the strain's safety for consumption. Based on these comprehensive analyses, NTU 101 is considered safe for regular consumption as a health supplement.

Reactive Extraction of Carboxylic Acids (Lactic, Propionic and Succinic Acids) using Tri-n-Butyl Amine Dissolved in Various Diluents

The current study intends to look into the extraction of lactic acid, propionic acid and succinic acids from aqueous solutions of these substances utilizing various solvent-extractant combinations to ascertain the most effective composition for the reactive extraction. The commercial value of succinic, propionic, and lactic acids in industrial processes led to their selection as the carboxylic acids. The process of recovering carboxylic acids from their aqueous solutions is accomplished by the Process Intensification method of reactive Tri-n-Butyl Amine was employed in the experiments because it has better stability, a lower water solubility, and is more eco-friendly than other extractants of the amine type. The extractants were dissolved in various diluents with various chemical structures, including 1-octanol, chloroform, and dimethylene chloride. Each experiment was conducted at 298.15 K. The distribution coefficient (KD), loading factor (Z), and extraction yield (%E) were used to compare the results in the range of 0.1 to 0.4 N acid concentration at various concentrations of Tri-n-Butyl Amine (10% to 40%). It was observed that at 0.1N and 40% amine concentration succinic acid attains a maximum distribution coefficient KD is 8.01 and equilibrium complexion KE1 is 7.5 for Tri-n-Butyl Amine, followed by propionic acid and lactic acid and a (1:1) type of acid amine complex was observed. The kinetic studies that were carried out using stirred cells to figure out the kinetic parameters such as order of the reaction with respect to acid and amine, mass transfer coefficient, and rate constant are also reported. The reaction with the highest Hatta number, MH=14, occurs in an instantaneous regime in 1-octanol when succinic acid and Tri-n-Butyl Amine interact.

Provolone del Monaco PDO cheese: Lactic microflora, biogenic amines and volatilome characterization

One commercial production run of Provolone del Monaco − a long-ripened pasta filata cheese − was followed up to the end of ripening for a total of 20 samples. 371 LAB isolates were subject to genetic characterization followed by 16S rRNA gene sequencing. The dominant species were Lacticaseibacillus casei/paracasei (19.4 %), Streptococcus macedonicus (19.1 %) and Enterococcus faecalis (13.2 %). Strains were screened for features of technological interest or safety relevance. Tyramine-producing cultures were quite common, above all within enterococci. By MALDI TOF Mass Spectrometry, one Lactococcus lactis and one Enterococcus faecium strain proved to be bacteriocin producers.Four further cheese wheels from the same production run at 623 days of ripening were evaluated for volatile organic compounds, biogenic amines, and bacterial community by metagenomic sequencing. Three individual wheel samples shared a rather similar microbiome with Lactobacillus delbrueckii and Streptococcus thermophilus as the most represented species, while the fourth wheel appeared wholly different being dominated by Lentilactobacillus buchneri and St. infantarius. Additionally, this sample had the greatest content of biogenic amines and a different VOCs composition.Given the variance seen among cheese wheels processed and ripened under the same conditions, the search for adjunct cultures in the production of this cheese seems to be of utmost importance.

Facile synthesis and biomimetic amine-functionalization of chitosan foam for CO2 capture

A high-performance biomass-based adsorption materials could be the promising trend for CO2 capture and storage technology. However, the direct application of biomass-based porous materials as a CO2 adsorbent with enhanced performance is an emerging issue. Herein, a facile synthesis and a biomimetic strategy were combined to prepare amine-functionalized chitosan foam for CO2 capture, and then a porous biomass is achieved for the application on the environment protection field. Firstly, the chitosan foam was synthesized by the emulsion-templating method at room temperature. Depended on stabilizing n-octane in the chitosan hydrogel with Span 80, a tunable three-dimensional network porous structure was obtained. Subsequently, co-deposition with dopamine (DA) and polyethyleneimine (PEI) was applied to load abundant amine content on the surface of chitosan foam and thereby improving CO2 adsorption capacity. Finally, the as-prepared amine-functionalized chitosan foam exhibited the impressive adsorption capacity of 3.59 mmol/g at 333 K and atmospheric pressure, and the better adsorption selectivity and stability. The results extend the preparation approach of biomass porous materials, and also its application in CO2 adsorption technology.

Modeling CO2 loading capacity of triethanolamine (TEA) aqueous solutions via a deep learning approach

Capturing carbon dioxide (CO2) from natural gas is essential for reducing CO2 emissions as a greenhouse gas as well as increasing the gas heating value. Absorption of CO2 by amine solutions is a method that has seen a widespread use as a CO2 collection technique. In this research, advanced ML approaches are utilized to simulate the CO2 loading capacity of triethanolamine (TEA) aqueous solutions as a function of system temperature, CO2 partial pressure, and amine concentration in the aqueous phase. Deep neural network (DNN), Gaussian process regressor (GPR), deep belief network (DBN), and bagging regressor (BR) are the models that have been developed. The DNN model with the coefficient of determination (R2) of 0.9990 as well as the root mean square error (RMSE) of 0.0073 outperformed other models in terms of accuracy and validity. The R2 values of 0.9911, 0.9861, and 0.9745 for DBN, BR, and GPR, accordingly, showed that other models could likewise perform with high accuracy. Moreover, trend analysis of the results confirmed that the DNN method can correctly estimate the behavior of CO2 loading with variations in the input parameters. Furthermore, sensitivity analysis showed that temperature has a decreasing effect on the CO2 loading, while amine concentration and CO2 partial pressure exhibited to have an incremental effect. Herein, the temperature had the greatest influence on the amount of CO2 loading. The final stage of the research was the leverage approach, which stated that about 99 % of the data are statistically valid and the DNN model is reliable to be replaced by experimental approaches in the prediction of CO2 absorption into certain type of solutions.

The metabolomic composition of the oviductal fluid is controlled by the periovulatory hormonal context in Bos indicus cows.

In cattle, oviductal function is controlled by the ovarian sex-steroids estradiol and progesterone. Here, we tested the hypothesis that the exposure to contrasting sex-steroid milieus differentially impacts the oviductal fluid composition. Estrous cycles of non-lactating, multiparous Nelore cows were pre-synchronized and then synchronized with a protocol designed two induce ovulation of large (LF group) or small (SF group) follciles. Larger preovulatory follicle (day 0) and corpora lutea (day 4) and greater estradiol (day 0) and progesterone (day 4) concentrations were observed in the LF group. Four days after induced ovulation, oviductal fluid was collected post-mortem. Quantitative mass spectrometry was used to determine the concentration of amino acids, biogenic amines, acylcarnitines, phosphatidylcholines, lysophosphatidylcholines, sphingomyelins, hexoses, prostaglandins and related compounds. Multivariate analyses (OPLS-DA) were conducted to compare the metabolomic signatures of oviductal fluids. Correlation network analysis was conducted to measure the strength and hierarchy of associations among metabolites. Of the 205 metabolites quantified, 171 were detected in at least 50% of the samples and were included in further data analysis. After OPLS-DA analysis, samples of the LF and SF were divided clearly into two non-overlapping clusters. Twenty metabolites had different or tended to have different concentrations in the oviductal fluid when comparing groups. Seven of these 20 analytes had greater concentrations in LF cows. Moreover, total sum of biogenic amines, phosphatidylcholines, and prostaglandins were higher in the SF group. The correlation network showed that the LF group metabolites' concentrations were highly intercorrelated, which was not observed in the SF group. We concluded that the periovulatory endocrine milieu regulates the composition of the oviductal fluid.

Microalgae aggregation induced by thermoresponsive polymers

Algal biomass harvesting is one of key technical hurdles impeding the commercialization of algae-based biorefinery. The goal of this work is to develop an innovative technology for algae cell harvesting. Thermoresponsive polymers (TRPs) such as poly(N-isopropylacrylamide) (PNIPAM) and its derivatives were studied on their properties and potential applications for microalgae harvesting. Various PNIPAM was synthesized, and the effects of charge, molecular weight (MW), amine content, and polymer concentration on the polymer phase transition temperature, the degree of phase separation, and the harvesting of microalgae (Chlorella vulgaris) were investigated. The lower critical solution temperature (LCST) of PNIPAM decreased with the increase of polymer concentration, while the decline rate reduced under high MW. The amine content didn’t significantly affect the LCST of TRPs. Approx. 92 % of algae cells were harvested by PNIPAM-300 kDa. Modified TRPs showed few benefits in enhancing algae harvesting. TRPs are a promising class of polymers for microalgae harvesting.

Research on CO2 capture performance and reaction mechanism using a novel low energy consumption and high cyclic performance absorbent for onboard application

High desorption energy consumption and low cyclic loading are critical issues limiting the application of onboard carbon capture (OCC) systems. In this study, a tetraethylenepentamine (TEPA) and 2–amino–2–methyl–1–propanol (AMP) mixed amine solvent with low desorption energy consumption and high CO2 cyclic loading, suitable for the operational environment of OCC systems, has been proposed. Detailed research was conducted on the capture performance and mechanism of the TEPA + AMP mixed amine solvent. The 0.25M TEPA+0.75M AMP mixed amine solvent exhibited the best performance, with an 86.5% increase in CO2 loading, a 214% increase in single–cycle CO2 loading, a 236% increase in CO2 loading after four cycles compared to monoethanolamine (MEA), and a 20.76% reduction in desorption energy consumption. In addition, to address the challenge of applying polyamine mixed solutions in the simulation studies of OCC systems, the capture mechanism was analyzed using density functional theory (DFT) calculations and nuclear magnetic resonance (NMR) characterization. The results indicated that increasing AMP promoted HCO3− formation in the TEPA + AMP mixed amine solvent. Since HCO3− decomposed more easily than carbamate, it reduced desorption energy consumption. However, an excess of AMP inhibited the absorption rate of TEPA, affecting the absorption capacity. Increasing the concentration of TEPA enhanced the amine concentration in the absorbent and improved the absorption performance. Nevertheless, excessive TEPA caused AMP to participate only in deprotonation reactions, which was not conducive to reducing desorption energy consumption.

Black and white truffles as a source of neuroactive biogenic amines

This study reports the first data about content of serotonin, histamine, and dopamine in black and white truffles fruiting body based on UHPLC-ESI-QqQ-MS/MS. Here we have demonstrated that black (Tuber macrosporum) and white (T. magnatum) truffles are a source of biogenic amines. Also, we demonstrated the absence of correlation between the quality of truffles and the content of biogenic amines.

Measurement report: Urban ammonia and amines in Houston, Texas

Abstract. Ammonia and amines play critical roles in secondary aerosol formation, especially in urban environments. However, fast measurements of ammonia and amines in the atmosphere are very scarce. We measured ammonia and amines with a chemical ionization mass spectrometer (CIMS) at the urban center in Houston, Texas, the fourth most populated urban site in the United States, during October 2022. Ammonia concentrations were on average four parts per billion by volume (ppbv), while the concentration of an individual amine ranged from several parts per trillion by volume (pptv) to hundreds of pptv. These reduced nitrogen compounds were more abundant during weekdays than on weekends and correlated with measured CO concentrations, implying they were mostly emitted from pollutant sources. Both ammonia and amines showed a distinct diurnal cycle, with higher concentrations in the warmer afternoon, indicating dominant gas-to-particle conversion processes taking place with the changing ambient temperatures. Studies have shown that dimethylamine is critical for new particle formation (NPF) in the polluted boundary layer, but currently there are no amine emission inventories in global climate models (as opposed to ammonia). Our observations made in the very polluted area of Houston, as well as a less polluted site (Kent, Ohio) from our previous study (You et al., 2014), indicate there is a consistent ratio of dimethylamine over ammonia at these two sites. Thus, our observations can provide a relatively constrained proxy of dimethylamine using 0.1 % ammonia concentrations at polluted sites in the United States to model NPF processes.