Citric Acid Research Articles

[Cadmium Phytoremediation Effect of Sweet Sorghum Assisted with Citric Acid on Typical Parent Soil in Southern China].

Sweet sorghum has a large biomass and strong cadmium (Cd) absorption capacity, which has the potential for phytoremediation of Cd-contaminated soil. In order to study the Cd phytoremediation effect of sweet sorghum assisted with citric acid on the typical parent materials in southern China, a field experiment was carried out in two typical parent material farmland areas (neutral purple mud field and jute sand mud field) with Cd pollution in Hunan Province. The results showed that:① Citric acid had no inhibitory effect on the growth of sweet sorghum. After the application of citric acid, the aboveground biomass of sweet sorghum at the maturity stage increased by 10.1%-24.7%. ② Both sweet sorghum planting and citric acid application reduced the soil pH value, and the application of citric acid further reduced the soil pH value at each growth stage of sweet sorghum; this decrease was greater in the neutral purple mud field, which decreased by 0.24-0.72 units. ③ Both sweet sorghum planting and citric acid application reduced the total amount of soil Cd, and the decreases in the neutral purple mud field and jute sand mud field were 23.8%-52.2% and 17.1%-31.8%, respectively. The acid-extractable percentage of soil Cd in both places increased by 38.6%-147.7% and 4.8%-22.7%, respectively. ④ The application of citric acid could significantly increase the Cd content in various tissues of sweet sorghum. The Cd content in the aboveground part of the plant in the neutral purple mud field was higher than that in the jute sand mud field, and the Cd content in stems and leaves was 0.25-1.90 mg·kg-1 and 0.21-0.64 mg·kg-1, respectively. ⑤ After applying citric acid, the Cd extraction amount of sweet sorghum in neutral purple mud soil in the mature stage reached 47.56 g·hm-2. In summary, citric acid could enhance the efficiency of sweet sorghum in the phytoremediation of Cd-contaminated soil, and the effect was better in neutral purple mud fields. This technology has the potential for remediation coupled with agro-production for heavy metal-contaminated farmland.

Utilizing experimental design and desirability function in optimizing RP-HPLC method for simultaneous determination of some skeletal muscle relaxants and analgesics

An experimental design and response surface methodologies using Plackett–Burman and Box-Behnken designs were applied for selecting and optimizing the most appropriate parameters which significantly affect the separation and quantitative estimation of five skeletal muscle relaxants and four analgesic drugs (baclofen, methocarbamol, dantrolene sodium, orphenadrine citrate, cyclobenzaprine hydrochloride, ketoprofen, etoricoxib, ibuprofen, and mefenamic acid) with a relatively short duration of analysis in a single run. For the separation of the nine drugs, an INERTSIL ODS-V3-5 µm C18 column (250 × 4.6 mm I.D.) was used with the optimum mobile phase conditions (45.15 mM ammonium acetate buffer pH 5.56 adjusted with acetic acid, acetonitrile, and methanol in a ratio of 30.5:29.5:40, v/v/v with a flow rate of 1.5 mL/min) and UV-detection at 220 nm. The optimized method was successfully subjected to the validation steps as described in ICH guidelines for linearity, precision, accuracy, robustness, and sensitivity. The optimized and validated method was effectively applied to determine the content of the studied drugs in their pharmaceutical preparations and to expand its applicability to the counterfeit estimation of etoricoxib in different brands of tablet dosage forms.

Evolutionary ecology of denitrifying methanotrophic NC10 bacteria in the deep-sea biosphere.

The NC10 phylum links anaerobic methane oxidation to nitrite denitrification through a unique O2-producing intra-aerobic methanotrophic pathway. Although numerous amplicon-based studies revealed the distribution of this phylum, comprehensive genomic insights and niche characterization in deep-sea environments were still largely unknown. In this study, we extensively surveyed the NC10 bacteria across diverse deep-sea environments, including waters, sediments, cold seeps, biofilms, rocky substrates, and subseafloor aquifers. We then reconstructed and analysed 38 metagenome-assembled genomes (MAGs), and revealed the extensive distribution of NC10 bacteria and their intense selective pressure in these harsh environments. Isotopic analyses combined with gene expression profiling confirmed that active nitrite-dependent anaerobic methane oxidation (n-DAMO) occurs within deep-sea sediments. In addition, the identification of the Wood-Ljungdahl (WL) and 3-hydroxypropionate/4-hydroxybutyrat (3HB/4HP) pathways in these MAGs suggests their capability for carbon fixation as chemoautotrophs in these deep-sea environments. Indeed, we found that for their survival in the oligotrophic deep-sea biosphere, NC10 bacteria encode two branches of the WL pathway, utilizing acetyl-CoA from the carbonyl branch for citric acid cycle-based energy production and methane from the methyl branch for n-DAMO. The observed low ratios of non-synonymous substitutions to synonymous substitutions (pN/pS) in n-DAMO-related genes across these habitats suggest a pronounced purifying selection that is critical for the survival of NC10 bacteria in oligotrophic deep-sea environments. These findings not only advance our understanding of the evolutionary adaptations of NC10 bacteria but also underscore the intricate coupling between the carbon and nitrogen cycles within deep-sea ecosystems, driven by this bacterial phylum.

PSIV-16 Evaluation of specialty soybean products and organic acids to alter nursery diet acid-binding capacity-4 on pig performance and fecal dry matter

Abstract A total of 300 weanling pigs (241 × 600, DNA, initial body weight = 5.6 ± 0.2 kg) were used to evaluate the effects of altering the acid-binding capacity-4 (ABC-4) of nursery diets with different specialty soybean products and organic acids on performance and fecal dry matter (DM). At weaning, pigs were allotted to 1 of 6 dietary treatments. There were 5 pigs/pen and 10 replications/treatment. Diet 1 was formulated with 12.0% specialty soy protein concentrate (AX3 Digest; Protekta; Newport Beach, CA), 1.06% citric acid, and 0.5% fumaric acid to achieve an ABC-4 of 223 meq/kg. Diets 2 and 3 were the same as diet 1 except citric and fumaric acid were reduced by 50 and 100% to achieve an ABC-4 of 280 or 338 meq/kg, respectively. Diets 4 and 5 were the same as diet 1 except 50 and 100% of the specialty soy protein concentrate was replaced with enzymatically treated soybean meal (HP 300; Hamlet Protein; Findlay, OH) on an SID Lys basis to achieve ABC-4 of 280 and 338 meq/kg, respectively. Diet 6 was a positive control with the same formulation as diet 5 except for the addition of 2,500 mg/kg of Zn from ZnO and a diet ABC-4 of 410 meq/kg. Dietary treatment structure allowed for the comparison of increasing ABC-4 (223 to 338 meq/kg) and formulation method (decreasing acidifier vs. specialty soy protein concentrate replacement) as well as their interactions. Pigs were fed the experimental diet for 24 d postweaning (d 0 to 24) followed by a common diet for an additional 18 d. There were no significant (P > 0.05) ABC-4 method × level interactions throughout the study (Table). From d 0 to 10, increasing ABC-4 decreased (linear, P = 0.042) gain to feed ratio (G:F) with no other differences in performance due to ABC-4. Formulation method influenced fecal DM with replacement of specialty soy protein concentrate (diets 4 and 5) reducing (P = 0.038) fecal DM compared with decreasing acidifier level (diets 2 and 3) on d 17. During the experimental period (d 0 to 24), pigs fed the diet with pharmacological Zn from ZnO had increased (P < 0.05) body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), and G:F compared with pigs fed diets without ZnO. In summary, pharmacological Zn from ZnO improved nursery pig performance when experimental diets were fed. Increasing ABC-4 and the formulation method had minimal effects on nursery pig performance; however, fecal DM was influenced by formulation method. Increasing ABC-4 from 223 to 338 meq/kg may not have been a large enough difference to observe a response to changing ABC-4 of the diet. Further research is warranted to determine the influence of lower ABC-4 levels or other ingredient changes to achieve target ABC-4.

148 Evaluating water characteristics and their effects on reducing water pH using citric acid

Abstract The goal of this experiment was to identify water characteristics that affect the ability to reduce pH when using water acidifiers. A total of 27 water samples from swine operations across the Midwest were collected and pH, Ca, and Mg were analyzed. Total hardness was calculated as the combined values of Ca and Mg and expressed in mg of CaCO3/L. Hardness values ranged from 142 mg CaCO3/L to 644 mg CaCO3/L, with an average hardness of 375 mg CaCO3/L. Initial sample pH ranged from 7.52 to 8.47 with an average value of 8.05. In triplicates, 10 mL of water from each source was titrated with citric acid (Citrasol Stock Booster, Northwest Livestock Distribution, Medina, MN) to reach a pH target of 5.0, 4.5, and 4.0 ± 0.05. The effects of individual characteristics were analyzed in R using the lm function to determine linear and quadratic relationships between water measurements and the amount of acid required to reach the target pH. As initial sample pH increased, a linear decrease in the amount of acid to reach the target pH of 4.0 was observed (P = 0.014, R2= 0.158). A significant but weak relationship (P = 0.016, R2= 0.179) between hardness and the amount of acid required to reach a pH of 4.0 was observed, where increasing hardness linearly increased the amount of acid required to reach a pH of 4.0. The quantity of Ca within the water source linearly increased (P = 0.023, R2= 0.159) the amount of acid required to reach a pH of 4.0 and a tendency for a quadratic relationship (P = 0.070, R2= 0.238) was also observed between Ca concentration of the water source and the amount of acid to reach a pH of 4.0. Magnesium concentrations also tended to linearly increase the amount of acid required to reach a final pH of 4.0 (P = 0.057, R2= 0.103). Titrating to either a pH of 5.0 (P < 0.001, R2 = 0.974) or 4.5 (P < 0.001, R2 = 0.990) also will predict the amount of acid required to reach a pH of 4.0. In conclusion, water hardness, Ca, Mg, and initial pH do not fully predict the amount of acid required to reduce water samples to a target pH of 4.0; however, weak relationships were observed that can partially explain the variation in acid requirements. These data suggest that acid titrations of water samples are required and should be site specific to establish an estimate for how much acid is required to reach a water pH of 4.0.

Pre-analytical challenges from adsorptive losses associated with thiamine analysis

Thiamine (vitamin B1) is an essential vitamin serving in its diphosphate form as a cofactor for enzymes in the citric acid cycle and pentose-phosphate pathways. Its concentration reported in the pM and nM range in environmental and clinical analyses prompted our consideration of the components used in pre-analytical processing, including the selection of filters, filter apparatuses, and sample vials. The seemingly innocuous use of glass fiber filters, glass filter flasks, and glass vials, ubiquitous in laboratory analysis of clinical and environmental samples, led to marked thiamine losses. 19.3 nM thiamine was recovered from a 100 nM standard following storage in glass autosampler vials and only 1 nM of thiamine was obtained in the filtrate of a 100 nM thiamine stock passed through a borosilicate glass fiber filter. We further observed a significant shift towards phosphorylated derivatives of thiamine when an equimolar mixture of thiamine, thiamine monophosphate, and thiamine diphosphate was stored in glass (most notably non-silanized glass, where a reduction of 54% of the thiamine peak area was observed) versus polypropylene autosampler vials. The selective losses of thiamine could lead to errors in interpreting the distribution of phosphorylated species in samples. Further, some loss of phosphorylated thiamine derivatives selectively to amber glass vials was observed relative to other glass vials. Our results suggest the use of polymeric filters (including nylon and cellulose acetate) and storage container materials (including polycarbonate and polypropylene) for thiamine handling. Losses to cellulose nitrate and polyethersulfone filters were far less substantial than to glass fiber filters, but were still notable given the low concentrations expected in samples. Thiamine losses were negated when thiamine was stored diluted in trichloroacetic acid or as thiochrome formed in situ, both of which are common practices, but not ubiquitous, in thiamine sample preparation.

Response of stevia (Stevia rebaudiana) to reduced risk synthetic and nonsynthetic herbicides applied post-transplant

Abstract Greenhouse trials were conducted to determine the response of stevia to reduce risk synthetic and nonsynthetic herbicides applied over-the-top post-transplant. In addition, field trials were conducted with stevia grown in a polyethylene mulch production system to determine crop response and weed control in planting holes to reduced risk synthetic and nonsynthetic herbicides applied post-transplant directed. Treatments included caprylic acid plus capric acid, clove oil plus cinnamon oil, d-limonene, acetic acid (200 grain), citric acid, pelargonic acid, eugenol, ammonium nonanoate, and ammoniated soap of fatty acids. Stevia yield (dry above ground biomass) in the greenhouse was reduced by all herbicide treatments. Citric acid and clove oil + cinnamon oil were the least injurious, reducing yield by 16 to 20%, respectively. In field studies, d-limonene, pelargonic acid, ammonium nonanoate, and ammoniated soap of fatty acids controlled Palmer amaranth > 90% 1 wk after treatment (WAT). In field studies caprylic acid plus capric acid, pelargonic acid, and ammonium nonanoate caused > 30% injury to stevia plant at 2 WAT, and D-limonene, citric acid, acetic acid, and ammoniated soap of fatty acids caused 18 to 25% injury 2 WAT. Clove oil plus cinnamon oil and eugenol caused < 10% injury. Despite being injurious, herbicides applied in the field did not reduce yield compared to the nontreated check. Based upon yield data, these herbicides have potential for use in stevia; however, these products could delay harvest if applied to established stevia. In particular, clove oil plus cinnamon oil has potential for use for early season weed management for organic production systems. The application of clove oil + cinnamon oil over-the-top resulted in <10% injury 28 DAT in the greenhouse and 3% injury 6 WAT POST-directed in the field. In addition, this treatment provided 95% control of Palmer amaranth 4 WAT.

Elucidating the Mechanism of Tetrahydrofuran-Diol Formation through Os(VI)-Catalyzed Oxidative Cyclization of 5,6-Dihydroxyalkenes Ligated by Citric Acid.

A computational study is reported here on the mechanism of tetrahydrofuran (THF)-diol formation from the Os(VI)-catalyzed oxidative cyclization of 5,6-dihydroxyalkene ligated with citric acid and in the presence of Bro̷nsted acid. Initiated by Os(VI) dioxo citrate formation, coordination of co-oxidant pyridine-N-oxide (PNO) and protonation of its oxo group generate the active catalyst. The catalytic cycle commences through successive steps, including dihydroxyalkene addition to the active catalyst in a concerted mechanism to form hexacoordinated alkoxy-protonated PNO-complexed Os(VI) bisglycolate as a turnover-limiting step (TLS), cyclization to Os(IV) THF-diolate, reoxidation to Os(VI) THF-diolate, and hydrolysis via a dissociative mechanism to furnish the THF-diol and regenerate the active species, sustaining the catalytic cycle through an Os(VI)/Os(IV) cycle. Despite the overall exergonic nature of catalytic cycle (ΔGrcycle = -45.0 kcal/mol), the TLS is accelerated by the formation of an open-valence 16-electron Os(VI) intermediate but decelerated by the undesired formation of a saturated/hexacoordinate 18-electron Os(VI) intermediate. Bro̷nsted acid plays crucial roles in the formation of Os(VI) citrate and the active catalyst, impediment of the second cycle, and the cyclization step. Additionally, besides its role as a co-oxidant, and in the presence of acid, PNO is found to assist the insertion of dihydroxyalkene and, importantly, in releasing the THF-diol to regenerate the active intermediate.

Variations in colostrum metabolite profiles in association with sow parity

Abstract Information about the full spectrum of metabolites present in porcine colostrum and factors that influence metabolite abundances is still incomplete. Parity number appears to modulate the concentration of single metabolites in colostrum. This study aimed to 1) characterize the metabolome composition and 2) assess the effect of parity on metabolite profiles in porcine colostrum. Sows (n = 20) were divided into three parity groups: A) sows in parity 1 and 2 (n = 8), B) sows in parity 3 and 4 (n = 6), and C) sows in parity 5 and 6 (n = 6). Colostrum was collected within 12 h after parturition. A total of 125 metabolites were identified using targeted reversed phase high-performance liquid chromatography tandem mass spectrometry and anion-exchange chromatography-high resolution mass spectrometry. Gas chromatography additionally identified 19 fatty acids (FA). Across parities, colostrum was rich in creatine and creatinine, 1,3-dioleyl-2-palmitatoylglycerol, 1,3-dipalmitoyl-2-oleoylglycerol and sialyllactose. Alterations in colostrum concentrations were found for 8 metabolites among parity groups (P < 0.05) but effects were not linear. For instance, colostrum from parity group C comprised 75.4% more valine but 15.7, 34.1 and 47.9% less citric, pyruvic and pyroglutamic acid, respectively, compared to group A (P < 0.05). By contrast, colostrum from parity group B contained 39.5% more spermidine than from group A (P < 0.05). Of the FA, C18:1, C16:0 and C18:2 n-6 were the main FA across parities. Parity affected four FA (C18:3n3, C14:1, C17:0ai and C17:1), including 43.1% less α-linolenic acid (C18:3n3) in colostrum from parity group C compared to groups A and B (P < 0.05). Signature feature ranking identified 1-stearoyl-2-hydroxy-sn-glycero-3-phosphatidylcholine and the secondary bile acid hyodeoxycholic acid as the most discriminative metabolites, showing a higher variable importance in the projection score in colostrum from parity group A than from groups B and C. Overall, results provided a comprehensive overview about the metabolome composition of sow colostrum. The consequences of the changes in colostrum metabolites with increasing parity for the nutrient supply of the piglets should be investigated in the future. The knowledge gained in this study could be used to optimize feeding strategies for sows.

A prototype system for the removal of 137Cs from liquid radioactive waste using reverse osmosis membrane.

Cesium removal from aqueous solutions of radioactive waste streams is a challenge in the field of radioactive waste management; this is due to the small atomic radii of Cs+ metal ions and their high migration ability. So, the development of a withstand system for the removal of Cs+ is crucial. In the current study, the removal of radioactive cesium from aqueous solutions using an RO-TLC membrane was studied. Two modifications were conducted; the first is to enlarge the cesium metal ion radii by interacting with mono- and dibasic acids, namely, stearic acid, tartaric acid, citric acid, and EDTA, and the second is the modification of the RO membrane pore size via reaction with the same acids. The modification was confirmed using SEM, FTIR, and EDX analysis techniques. The Cs+ and K+ rejection capacities and water permeability across the membrane at 1.5 bars were evaluated. Along with using the above-mentioned acids, the Cs+ metal ion retention index (RCs) was also obtained. It was found that employing EDTA as a chelating agent in an amount of 1.5g/L in conjunction with the variation of feed content since it provided the highest value of RCs ~ 98% when used. Moreover, the elution of Cs+ using water, EDTA, ammonia, and HCl is also investigated. The optimal value of the eluent concentration was (0.25M) HCl. Finally, Langmuir and Freundlich isotherm models were applied for a better understanding of the sorption process. The results of the present work more closely match the Langmuir isotherm model to determine the dominance of the chemical sorption mechanism.

Identification and Characterization of a Bacterial Periplasmic Solute Binding Protein That Binds l-Amino Acid Amides.

Periplasmic solute-binding proteins (SBPs) are key ligand recognition components of bacterial ATP-binding cassette (ABC) transporters that allow bacteria to import nutrients and metabolic precursors from the environment. Periplasmic SBPs comprise a large and diverse family of proteins, of which only a small number have been empirically characterized. In this work, we identify a set of 610 unique uncharacterized proteins within the SBP_bac_5 family that are found in conserved operons comprising genes encoding (i) ABC transport systems and (ii) putative amidases from the FmdA_AmdA family. From these uncharacterized SBP_bac_5 proteins, we characterize a representative periplasmic SBP from Mesorhizobium sp. A09 (MeAmi_SBP) and show that MeAmi_SBP binds l-amino acid amides but not the corresponding l-amino acids. An X-ray crystal structure of MeAmi_SBP bound to l-serinamide highlights the residues that impart distinct specificity for l-amino acid amides and reveals a structural Ca2+ binding site within one of the lobes of the protein. We show that the residues involved in ligand and Ca2+ binding are conserved among the 610 SBPs from experimentally uncharacterized FmdA_AmdA amidase-associated ABC transporter systems, suggesting these homologous systems are also likely to be involved in the sensing, uptake, and metabolism of l-amino acid amides across many Gram-negative nitrogen-fixing soil bacteria. We propose that MeAmi_SBP is involved in the uptake of such solutes to supplement pathways such as the citric acid cycle and the glutamine synthetase-glutamate synthase pathway. This work expands our currently limited understanding of microbial interactions with l-amino acid amides and bacterial nitrogen utilization.

Relationships between nutrients in the soil and nutritional status of Pinus taeda stands in southern Brazil

The characterization of nutrients availability in the soil and its relationship with nutritional status and productivity of Pinus taeda stands in southern Brazil is still of concern due the lack of research on this subject. We compared different methods to evaluate P, K, Ca, and Mg in the soil and in plant tissues. We performed the evaluations in six paired plots (control and fertilized) located on different soils conditions in southern Brazil. Availability of nutrients in the soil was obtained after extractions of soil solutions with the extractors Mehlich I (P, K), KCl 1 mol L−1 (Ca, Mg), and 1 % citric acid (P, K, Ca, Mg). Foliar and wood samples were collected to determine the P, K, Ca, and Mg contents in the trees’ tissues. The mean annual increment (MAI) of each plot was obtained from the annual inventories of the P. taeda stands. The contents of P, K, Ca, and Mg in the soil followed similar trends for the different extractors tested, with higher contents of Ca and Mg in the fertilized plots. No differences for P and K in the soil were observed between control and fertilized plots for both methods applied. The fertilized plots showed increase for Ca and Mg in the wood tissues but not in the needles. Positive correlation between wood and needle tissues was observed only for the P content. No correlation between the nutrient contents in the needles and in the soil was observed. But we found a positive correlation between the nutrient contents in the wood and in the soil, mainly for the 1% citric acid method. No correlation was found between the nutrients in the plant tissues and the productivity of Pinus taeda. Our results improved the knowledge concerning the nutrient dynamics in P. taeda stands in southern Brazil showing that citric acid is a good extractor for P, K, Ca, and Mg in the soil, and that determination of nutrients in the wood tissues is a potential method for nutritional diagnosis of P. taeda.

Self-healing photo-polymerized thiol-ene networks utilizing bio-based hexaallylated compounds derived from L-cystine and citric acid

Bio-based vitrimers have received considerable attention owing to their contributions to carbon neutrality and resource and energy savings. The photopolymerization of hexaallylated compounds (A6CST and A6UDC) derived from L-cystine and citric acid with disulfide-containing polyether dithiol (LP-12) and pentaerythritol-based tetrathiol (S4P) at an allyl:thiol ratio of 1:1 produced thiol-ene network films. Fourier-transform infrared spectroscopy of the cured films revealed that the thiol-ene reaction of the thiol and allyl groups was almost complete. Degrees of swelling of the cured films decreased with an increasing LP-12/S4P ratio. The A6CST- and A6UDC-cured films with higher flexible LP-12 fractions (i.e., higher disulfide contents) exhibited lower glass transition temperatures (Tgs), tensile strengths, and tensile moduli, and could be healed by treatment at a lower temperature and shorter time. The A6CST/S4P cured film was healed by treating at 100 ℃ for 24 h, whereas the A6UDC/S4P cured film without disulfide bond was not healed by the same treatment. The A6CST-based film with the highest LP-12/S4P ratio exhibited the highest healing efficiency (99 %) after treatment at room temperature for 10 h, and self-healed at least three times.

Chemical composition and antioxidant properties of native Ecuadorian fruits: Rubus glabratus Kunth, Vaccinium floribundum Kunth, and Opuntia soederstromiana

The native berries of South America present promising marketing opportunities owing to their high antioxidant content, notably rich in anthocyanin and phenolic compounds. However, Ecuador’s endemic fruits, primarily found in the wild, lack comprehensive data regarding their phytochemical composition and antioxidant capacity, underscoring the need for research in this area. Accordingly, this study evaluated the total phenolic, anthocyanin, flavonoid, resveratrol, ascorbic acid, citric acid, sugars, and antioxidant content of three native Ecuadorian fruits: mora de monte (Rubus glabratus Kunth), mortiño (Vaccinium floribundum Kunth), and tuna de monte (Opuntia soederstromiana). Determination of resveratrol, ascorbic acid, citric acid, and sugars was determined by HPLC analysis, and UPLC analysis was used to determine tentative metabolites with nutraceutical properties. Antioxidant capacity was assessed using cyclic voltammetry and the DPPH method; differential pulse voltammetry was used to evaluate antioxidant power. Analysis of results through UPLC-QTOF mass spectrometry indicated that R. glabratus Kunth and V. floribundum Kunth are important sources of various compounds with potential health-promoting functions in the body. The DPPH results showed the following antioxidant capacities for the three fruits: R. glabratus Kunth ˃ O. soederstromiana ˃ V. floribundum Kunth; this trend was consistent with the antioxidant capacity results determined using the electrochemical methods.

Study on pulp metabolism of patients with pulpitis using ultra-performance liquid chromatography coupled with Orbitrap mass spectrometry

Background and aimsPulpitis, a pulp disease caused by caries, trauma, and other factors, has a high clinical incidence. This study focused on identifying possible metabolic biomarkers of pulpitis cases and analyzing the related metabolic pathways for providing a theoretical foundation to diagnose and prevent pulpitis. Materials and methodsPulp samples from 20 pulpitis cases together with 20 normal participants were analyzed with a serum metabolomics approach using ultra-high-performance liquid chromatography (UPLC)/Orbitrap mass spectrometry. Moreover, this work carried out multivariate statistical analysis for screening potential biomarkers of pulpitis. ResultsThrough biomarker analysis and identification, such as partial least squares discrimination analysis, orthogonal partial least squares discriminant analysis model establishment, correlation analysis, and biomarker pathway analysis, 40 biomarkers associated with 20 metabolic pathways were identified, including 20 upregulated and 20 downregulated metabolites. Those major biomarkers included oxoglutaric acid, inosine, citric acid, and PA(14:1(9Z)/PGD1). Among them, oxoglutaric acid and inosine were most significantly downregulated and had the highest correlation with pulpitis. Among these metabolic pathways, GABAergic synapse and alanine, aspartate, and glutamate metabolism were positively correlated with pulpitis. 4. ConclusionsThese biomarkers as well as metabolic pathways may offer the theoretical foundation to understand pulpitis pathogenesis and develop preventive drugs.

A sterilizable platform based on crosslinked xanthan gum for controlled-release of polymeric micelles: Ocular application for the delivery of neuroprotective compounds to the posterior eye segment

TPGS (D-α-tocopheryl polyethylene glycol 1000 succinate) polymeric micelles show interesting properties for ocular administration thanks to their solubilization capability, nanometric size and tissue penetration ability. However, micelles formulations are generally characterized by low viscosity, poor adhesion and very short retention time at the administration site. Therefore, the idea behind this work is the preparation and characterization of a crosslinked film based on xanthan gum that contains TPGS micelles and is capable of controlling their release. The system was loaded with melatonin and cyclosporin A, neuroprotective compounds to be delivered to the posterior eye segment. Citric acid and heating at different times and temperatures were exploited as crosslinking approach, giving the possibility to tune swelling, micelles release and drug release. The biocompatibility of the platform was confirmed by HET-CAM assay. Ex vivo studies on isolated porcine ocular tissues, conducted using Franz cells and two-photon microscopy, demonstrated the potential of the xanthan gum-based platform and enlightened micelles penetration mechanism. Finally, the sterilization step was approached, and a process to simultaneously crosslink and sterilize the platform was developed.

Contribution of Hurdles Technology to Preserve the Qualities of Broccoli and Extend Their Shelf-Life

Due to its high concentration of bioactive components, broccoli heads have a lot of potential as a functional food. Broccoli is perceived as a tasty, wholesome and healthful food product. This product nevertheless has a limited shelf life and quality retention issues, especially in tropical temperature zones. The hurdles techniques are starting to become more acceptable in the sector of food preservation since they affect moderate levels. This study evaluates the impact of hurdles techniques and various storage conditions (ambient at 25 °C, cold at 4 °C, and frozen at -18 °C) on broccolis cut characteristics. For the hurdles experiment, broccoli cuts were soaked in four solutions (the 1st: boiling water, the 2nd: metabisulphite solution (150 ppm), the 3rd: sodium chloride (4%), citric acid (1%), sodium benzoate (200 ppm) and the 4th: 1% chitosan) followed by packaging using two approaches (aerobic and vacuum). Sensory attributes, browning index, ascorbic acid, total phenolic, total flavonoids and antioxidant activity % (by DPPH, ABTS and FRAP) of hurdled and un-hurdled broccoli cuts during storage were investigated. Results demonstrated that using hurdle technology (different soaking solutions, packaging methods and storage conditions) had significant impact on the quality properties of the broccoli cuts. Additionally, vacuum packaging demonstrated the highest protection against decreasing the values of ascorbic acid, total phenolic, total flavonoid, and antioxidant components.

Fabrication of g-C3N4 films with enhanced mechanical and charge transfer properties by electrophoretic deposition and subsequent citric acid modification

A low-cost 2D metal-free material based on a graphitic carbon nitride (g-C3N4) film functionalized with a citric acid molecule has been successfully fabricated by Electrophoretic Deposition (EPD) and thermal techniques, aiming to evaluate its suitability for optoelectronic devices. The thickness-controlled g-C3N4 film having a good mechanical property was successfully performed. The chemical stability and photostability of the citric-modified g-C3N4 films deposited on indium tin oxide (ITO) glass were investigated. New chemical links were clarified such that it could possibly become a bridge for enhancing charge transport. The modified samples exhibited a significant increase in their photocurrent response, reaching 25 μA/cm2 at a thickness of about 20 μm. Electrochemical impedance spectra (EIS) verified the enhanced conductivity, efficient charge transfer, and reduced electron-hole recombination rate. This research revealed a facile synthetic route and environmentally benign materials, thereby suggesting promising prospects for their application in the optoelectronic field.

Iron ion detection and life cycle assessment of cutting fluid based on photoluminescent nitrogen-doped carbon quantum dots

Cutting fluid (CF) ensures machining accuracy and improves tool life in machining, which is of great significance for its impurity content detection and life cycle evaluation. In this paper, citric acid and arginine were used as carbon and nitrogen sources, photoluminescent (PL) nitrogen-doped carbon quantum dots (N-CDs) with a particle size ranging from 8 to 14 nm and well dispersion in water-based CF were synthesized by a one-pot hydrothermal reaction method. The N-CDs have the best signal under 360 nm ultraviolet light excitation, which well avoids the autofluorescence of the CF. The N-CDs dispersion have good selectivity and linearity in the Fe3+ concentration range of 2 to 80 μM, and the detection limit is 1.2 μM. The N-CDs were used to detect the concentration of Fe3+ in CF with different working hours, and the results were consistent with the results of coupled plasma emission spectroscopy. This study provides an intelligent sensing platform for the highly sensitive and selective detection of Fe3+ in the CF environment, and provides a promising strategy for the evaluation of the CF lifetime.

Microwave-assisted and methanol/acetic acid-free method for rapid staining of proteins in SDS-PAGE gels

We describe a microwave-assisted, methanol and acetic acid-free, inexpensive method for rapid staining of SDS-PAGE proteins. Only citric acid, benzoic acid, and Coomassie brilliant blue G-250 (CBG) were used. Microwave irradiation reduced the detection duration, and proteins in a clear background were visualized within 30 min of destaining, after 2 min of fixing and 12 min of staining. By using this protocol, comparable band intensities were obtained to the conventional methanol/acetic acid method.