An ultrasensitive green synchronous factorized spectrofluorimetric approach for the simultaneous determination of Favipiravir and Molnupiravir: Application to pharmaceutical, environmental, and biological matrices.

During the pandemic, Favipiravir (FVP) and Molnupiravir (MPV) have been widely used for COVID-19 treatment, leading to their presence in the environment. A green synchronous spectrofluorimetric method was developed to simultaneously detect them in environmental water, human plasma, and binary mixtures. Maximum fluorescence intensity was achieved at pH 8, with MPV exhibiting two peaks at 300 and 430 nm, and FVP showing one peak at 430 nm. A fluorescence subtraction method effectively removed interference, enabling direct determination of MPV at 300 nm and FVP at 430 nm. The method showed linearity within 2-13 ng/mL for FVP and 50-600 ng/mL for MPV, with recoveries of 100.35% and 100.12%, respectively. Limits of detection and quantification were 0.19 and 0.57 ng/mL for FVP and 10.52 and 31.88 ng/mL for MPV. Validation according to ICH and FDA guidelines yielded acceptable results. The method demonstrated good recoveries of FVP and MPV in pharmaceuticals, tap water and Nile water (99.62% ± 0.96% and 99.69% ± 0.64%) as per ICH guidelines and spiked human plasma (94.87% ± 2.111% and 94.79% ± 1.605%) following FDA guidelines, respectively. Its environmental friendliness was assessed using Green Analytical Procedure Index (GAPI) and the Analytical Greenness Metric (AGREE) tools.

Long term study on the fate and environmental risks of favipiravir in wastewater treatment plants and comparison with COVID-19 cases.

In recent years especially during COVID-19, the increased usage of antiviral drugs has led to increased interest in monitoring their presence in wastewater worldwide. In this study, it was examined the occurrence, fate and environmental risks of favipiravir which is used for COVID-19 treatment in two wastewater treatment plants (WWTPs) with different treatment processes in Istanbul, Turkey. Favipiravir was measured in WWTPs influent samples, effluent samples and sludge samples with maximum concentrations of 97 µg/L, 64.11 µg/L and 182.47 µg/g, respectively. Favipiravir had removal efficiency below 55 % for both WWTPs. Mass balance analysis showed that favipiravir removal in WWTPs mainly attributed to biodegradation/biotransformation. Statistical analysis revealed a significant correlation between favipiravir concentration and COVID-19 incidence in Istanbul. The microbial distribution analysis indicated that comparison of collected COVID-19 pandemic sludge and post-pandemic period sludge samples, a noteworthy reduction in the Chloroflexi and Actinobacteriota phyla at the phylum level was observed. Environmental risk assessment using risk quotients ranged from 168 to 704, indicating that the presence of this antiviral drug posed significant ecological risks to aquatic organisms. The study concluded that WWTPs were releasing antiviral drugs into the environment, thereby posing risks to both the aquatic ecosystem and public health. The results of this study demonstrate the persistence of favipiravir in WWTPs and offer crucial supporting data for further research into the advancement of wastewater treatment technology. Also, this study shows wastewater based monitoring is supplementary and early warning system for determining the occurrence of antiviral drugs.

Analyte protectant approach to protect amide-based synthetic cannabinoids from degradation and esterification during GC-MS analysis.

The forensic analysis of amide-based synthetic cannabinoids (SCs) in seized materials is routinely performed using gas chromatography-mass spectrometry (GC-MS); however, a major challenge associated with GC-MS is the thermolytic degradation of substances with sensitive functional groups. Herein, we report the comprehensive thermal degradation and ester transformation of amide-based SCs, such as AB-FUBINACA, AB-CHMINACA, and MAB-CHMINACA, during GC-MS analysis and their treatment with analyte protectants (APs). These SCs were found to undergo thermolytic degradation during GC-MS in the presence of non-alcohol solvents. Using methanol as an injection solvent resulted in the conversion of the amide group to an ester group, producing other SCs such as AMB-FUBINACA, MA-CHMINACA, and MDMB-CHMINACA. Degradant and ester product formation has been interpreted as the adsorption of target SCs on glass wool via hydrogen bonding interactions between the active silanol and amide groups of the SCs, followed by an addition and/or elimination process. The factors found to influence the thermal degradation and/or esterification of the amide functional group include residence time, activity of glass wool, and injection volume. This report presents the fragmentation patterns of all compounds that were produced by degradation and esterification. Using 0.5 % sorbitol (AP) in MeOH as an injection solvent resulted in complete protection and improvement of the chromatographic shape of the compounds. This method has been successfully confirmed in terms of sensitivity, linearity, accuracy, and precision for standard solutions and tablet extraction using 0.5 % sorbitol in MeOH. Using AP increased the sensitivity by ten times or more compared to the use of only MeOH. The limit of detection for all analytes was determined as 25 ng/mL, and the calibration curves were linear over the concentration range of 50-2000 ng/mL. The values of accuracy error were below 11 %, and precision was less than 13 %. The effects of phytochemicals of herbal products, tablet ingredients, and biological matrices on the degradation and/or esterification and APs performance have also been evaluated in this work.

Retention mechanisms of amitriptyline and its impurities on amide, amino, diol, and silica columns in hydrophilic interaction liquid chromatography.

Hydrophilic interaction liquid chromatography (HILIC) has been widely applied to challenging analysis in biomedical and pharmaceutical fields, bridging the gap between normal-phase high-performance liquid chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC). This paper comprehensively explores the retention mechanisms of amitriptyline and its impurities A, B, C, D, F, and G on amide, amino, diol, and silica columns. Dual HILIC/RP-HPLC retention mechanisms were developed, and transitional points between HILIC and RP-HPLC mechanisms were calculated on amide, diol, and silica columns. Adsorption and partition contributions to overall retention mechanisms were evaluated using Python software in HILIC and RP-HPLC regions. The cation exchange mechanism dominates overall retention for ionized analytes in the silica column (R2 > 0.995), whereas the retention of ionized analytes increases with pH. Impacts of acetonitrile content, buffer ionic strength, and pH, along with their interactions on the retention of ionized analytes in the silica column, were determined using the chemometric approach. Acetonitrile content showed the most significant impact on the retention mechanisms. These findings highlight that a detailed investigation into retention mechanisms provides notable insights into factors influencing analyte retention and separation, promising valuable guidance for future analysis.

QbD-Based Stability-Indicating RP-HPLC Method Development and Validation for the Estimation of Favipiravir-An Eco-Friendly Approach.

BACKGROUND: Analytical quality by design (AQbD) affords a systematic scaffolding to triumph a continuously validated, robust assay as well as life cycle management. The resuscitative repurposed drug favipiravir, an oral drug approved for reemerging pandemic influenza in Japan in 2014, is used for the treatment of life-threatening pathogens such as Ebola, Lassa virus, and currently COVID-19. Favipiravir is gaining a great deal of medical importance due to its pharmaceutical applications. OBJECTIVE: To develop and validate a risk-based stability-indicating RP-HPLC method employing an AQbD approach using Central Composite Design (Design Expert Software 13.0) for the estimation of favipiravir. METHOD: The Quality Target Product Profile optimized were flow rate and mobile phase composition, thus assessing the critical analytical attributes (retention time, tailing factor, and number of theoretical plates) as the constraints of method robustness. The proposed technique was optimized with a C18 (150 × 4.6 mm, 5 µm) column and 0.1% orthophosphoric acid buffer-acetonitrile (50:50, v/v) as the mobile phase at a flow rate of 1 mL/min using diode-array detector (230 nm) eluted favipiravir at 2.3 min. RESULTS: The optimized method validated as per ICH guideline Q2 (R1) was found to be eco-friendly, simple, precise (RSD 0.0051-1.2%), accurate (99.86-100.22%), linear (25-150 µg/mL), rugged (RSD 0.70%), and robust (RSD 0.6-1.6%) with a limit of detection and limit of quantitation of 1.140 µg/mL and 4.424 µg/mL, respectively. CONCLUSION: Forced degradation studies (acidic, alkaline, thermal, photolytic, and oxidative conditions) revealed the suitability of the AQbD method for the analysis of favipiravir in tablet formulation.The developed and validated AQbD method is less time consuming and can be used in the industry for routine quality control/analysis of bulk drug and marketed Favipiravir products. HIGHLIGHTS: A robust Design of Experiment enhanced stability-indicating analytical method was developed and validated for the estimation of favipiravir. Furthermore, the contemporary method would aid in extending the analysis of favipiravir in other formulations.

An Eco-Friendly RP-HPLC Method Development and Validation for Quantification of Favipiravir in Bulk and Tablet Dosage Form Followed by Forced Degradation Study.

In this work, an eco-friendly simple, precise reverse phase high-performance liquid chromatography (HPLC) method has been developed and validated for Favipiravir in bulk and tablet dosage form followed by its force degradation study. The proposed method was validated to obtain official requirements including stability, accuracy, precision, linearity, robustness and selectivity as per International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Guidelines. The estimation was developed on C (18) column reversed-phase using the mobile phase composition as methanol:water (10:90 v/v). The flow rate was set as 1 ml/min, and the maximum absorption was observed at 323 nm using Shimadzu Photo Diode Array detector. The Favipiravir, drug showed a precise and good linearity at the concentration ranges of 10-50 µg/mL. The Revearse Phase High Perforance Liquid Chromatography assay showed the highest purity ranging from 99.90 to 100.02% for Favipiravir, tablet dosage form, and 100.15% was the mean percentage purity. The percent recovery was found within the acceptance limit of (98.6-100.0%). Intra- and inter-day precision studies of the method were less than the maximum allowable limit percentage of relative standard deviation ≤ 2.0. The Favipiravir retention time was found to be 5.00 min. To examine the stability of the drug, various forced degradation studies were conducted on Favipiravir Active Pharmaceutical Ingredient. The developed method was validated according to the ICH guidelines. A very quick, cost-effective, precise and accurate HPLC method for the determination of Favipiravir has been developed and validated in compliance with ICH guidance Q2.

Comparative study of the structure and mechanical properties of starch aerogels fabricated from air-classified and isolated pulse starches.

Significant amounts of starch and protein are generated as co-products during fractionation of pulse seeds. While pulse proteins (PP) have garnered a lot of interest in numerous applications, little attention is shown to pulse starch (PS). The creation of novel materials such as bioplastics could revolutionize the use of pulse starches. In this study, we investigated the prospects of air-classified and isolated pea, lentil, and faba bean starches as a precursor for fabricating pulse starch bioaerogels (PSBs) via freeze-drying technique. The results evidenced ultra-low densities (<0.1 m2/g), mesopore sizes (2-50 µm), high porosities (∼99 %), low surface areas (SBET = âˆ¼4-18 m2/g) for all the aerogels. The adsorption isotherm showed typical Type II and III profiles, while the thermogravimetric analysis showed more weight loss (74.39-78.12 %) in aerogels mostly developed from isolated starches. Microstructural studies showed a unique distribution of pores within the developed aerogels. FTIR and XPS studies confirmed the presence of an amide (I, II, III) at different absorption bands range (∼1600-1200 cm-1) and functional groups (carboxylic group and the amide group), respectively. All the PSBs became stiffer with a corresponding increase in load, and a reversible deformation in the linear region was identified at <5 % strain. Comparatively, saturated PSBs from air-classified starch at a relative humidity of 95 % showed a drastic reduction in their compressive moduli (CM), while PSBs from isolated starch experienced markedly high CM. Moisture saturation was achieved at 72 h for all the samples. This study provides crucial information that could spark a keen interest in the use of non-conventional starch for the creation of novel and sustainable biobased products with expanded applications.

Radiotherapy in the head and neck region influences the chemical and mechanical properties of intraradicular dentin.

OBJECTIVES: To investigate the chemical and mechanical properties of intraradicular dentin submitted to radiotherapy. MATERIALS AND METHODS: Sixteen mandibular incisors were divided into two groups (n = 8): non-irradiated and irradiated. The irradiated teeth were obtained from head and neck radiotherapy patients, with a total dose ranging from 70.2 to 72 Gy divided into 1.8 Gy daily. After sample preparation, intraradicular dentin slices of each root third were evaluated by Raman spectroscopy, energy dispersive spectroscopy and Knoop microhardness test. Data were analyzed by Two-way ANOVA and Tukey's test (α = 0.05). RESULTS: In Raman spectroscopy, carbonate and amide III showed a significant difference for irradiation and third (carbonate p = 0.021 and p < 0.001; amide III p < 0.001 and p = 0.001, respectively). For amide I, there was a significant difference for third (p < 0.001). For carbonate/mineral ratio, there was a significant difference for irradiation (p = 0.0016) and third (p < 0.001), with the irradiated middle third showing the lowest values. For amide I/amide III ratio, there was a significant difference for irradiation (p = 0.005) in the cervical third. In energy dispersive spectroscopy, carbon (p = 0.004; p = 0.020), phosphorus (p < 0.001; p = 0.009) and calcium (p = 0.008; p = 0.007) showed differences for irradiation and third, with the irradiated groups presenting lower values in cervical and middle thirds. For calcium/phosphorus ratio, there was a significant difference for irradiation (p < 0.001) in cervical and middle thirds. Regarding microhardness, there was a significant difference for irradiation (p < 0.001), with all irradiated groups showing lower microhardness values. CONCLUSIONS: The radiotherapy altered the chemical and mechanical properties of intraradicular dentin, mainly in the cervical and middle root thirds.

Minimally invasive management of vital teeth requiring root canal therapy.

The present study aimed to investigate the possible use of a non-instrumentation technique including blue light irradiation for root canal cleaning. Extracted human single rooted teeth were selected. Nine different groups included distilled water, NaOCl, intra-canal heated NaOCl, and NaOCl + EDTA irrigation after either instrumentation or non-instrumentation, and a laser application group following non-instrumentation technique. The chemical assessment of the root canal dentine was evaluated using energy dispersive spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy. Surface microstructural analyses were performed by using scanning electron microscopy (SEM). The antimicrobial efficacy of different preparation techniques was evaluated using microbial tests. Light application didn't change the calcium/phosphorus, carbonate/phosphate and amide I/phosphate ratios of the root canal dentin. The root canal dentin preserved its original chemistry and microstructure after light application. The instrumentation decreased the carbonate/phosphate and amide I/phosphate ratios of the root canal dentin regardless of the irrigation solution or technique (p < 0.05). The application of light could not provide antibacterial efficacy to match the NaOCl irrigation. The NaOCl irrigation both in the non-instrumentation and instrumentation groups significantly reduced the number of bacteria (p < 0.05). The use of minimally invasive root canal preparation techniques where the root canal is not instrumented and is disinfected by light followed by obturation with a hydraulic cement sealer reduced the microbial load and preserved the dentin thus may be an attractive treatment option for management of vital teeth needing root canal therapy.

Effect of carnosine synthesis precursors in the diet on jejunal metabolomic profiling and biochemical compounds in slow-growing Korat chicken.

The slow-growing Korat chicken (KR) has been developed to provide an alternative breed for smallholder farmers in Thailand. Carnosine enrichment in the meat can distinguish KR from other chicken breeds. Therefore, our aim was to investigate the effect of enriched carnosine synthesis, obtained by the ß-alanine and L-histidine precursor supplementation in the diet, on changes to metabolomic profiles and biochemical compounds in slow-growing KR jejunum tissue. Four hundred 21-day-old female KR chickens were divided into 4 experimental groups: a group with a basal diet, a group with a basal diet supplemented with 1.0% ß-alanine, 0.5% L-histidine, and a mix of 1.0% ß-alanine and 0.5% L-histidine. The feeding trial lasted 70 d. Ten randomly selected chickens from each group were slaughtered. Metabolic profiles were analyzed using proton nuclear magnetic resonance spectroscopy. In total, 28 metabolites were identified. Significant changes in the concentrations of these metabolites were detected between the groups. Partial least squares discriminant analysis was used to distinguish the metabolites between the experimental groups. Based on the discovered metabolites, 34 potential metabolic pathways showed differentiation between groups, and 8 pathways (with impact values higher than 0.05, P < 0.05, and FDR < 0.05) were affected by metabolite content. In addition, biochemical changes were monitored using synchrotron radiation-based Fourier transform infrared microspectroscopy. Supplementation of ß-alanine alone in the diet increased the ß-sheets and decreased the α-helix content in the amide I region, and supplementation of L-histidine alone in the diet also increased the ß-sheets. Furthermore, the relationship between metabolite contents and biochemical compounds were confirmed using principal component analysis (PCA). Results from the PCA indicated that ß-alanine and L-histidine precursor group was highly positively correlated with amide I, amide II, creatine, tyrosine, valine, isoleucine, and aspartate. These findings can help to understand the relationships and patterns between the spectral and metabolic processes related to carnosine synthesis.

Preparation and functional characteristics of protein from Ginkgo endophytic Pseudomonas R6 and Ginkgo seed.

Ginkgo seed protein (GSP) has excellent processing characteristics and antioxidant properties. In this study, Gingko endophytic protein (GEP) was synthesized by Ginkgo endophytic Pseudomonas R6. SDS-PAGE analysis indicated that the molecular weights of GSP and GEP were mainly distributed at 17 KDa and 48 KDa, respectively. FTIR showed that GEP and GSP exhibited characteristic absorption in the amide I, II, and III bands, and absorption in amide A and B indicated the presence of hydrogen bonding. HPLC analysis showed that both proteins had 17 amino acids, but their relative abundance was different, with GSP having the highest Ser content (74.713 mg/g) and GEP having the highest Val content (35.905 mg/g). Stomata were observed on the surface of both proteins by SEM, and there were lamellar and some spherical structures on GEP, while the opposite was observed on GSP. GEP had superior solubility, OHC, FC and EC, while GSP showed good WHC. Both proteins exhibited antioxidant activities, with GSP exhibiting stronger hydroxyl radical scavenging ability than GEP, with IC50 of 0.46 mg/mL and 1.54 mg/mL, respectively. This work demonstrates the antioxidant potential of GEP as an alternative to GSP in the food industry.

A new amide from the fruiting bodies of Tricholoma bakamatsutake.

A new amide tricholomine C was isolated from the dried fruiting bodies of Tricholoma bakamatsutake. Its structure was identified by a combination of nuclear magnetic resonance spectroscopic analysis and electronic circular dichroism (ECD) calculations. The ethyl alcohol crude extract and tricholomines A-C from T. bakamatsutake were evaluated for neuroprotective activities. Of these substances, the crude extract showed weak neurite outgrowth-promoting activity in rat pheochromocytoma (PC12) cells, as well as weak inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE).

Developing a hydroxyl-functionalized magnetic porous organic polymer combined with HPLC-MS/MS for determining 31 amide herbicides in fruit wine.

More and more attention has been paid to undesirable chemical contaminants from food raw materials and ingredients. The study aimed to fabricate novel hydroxyl-functionalized magnetic porous organic polymer Fe3O4@SiO2-NH2@Ph-POP and explore its use as magnetic adsorbents for magnetic solid-phase extraction (MSPE) for extracting 31 amide herbicides from fruit wine samples prior to high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Several operational parameters were optimized and the as-prepared magnetic polymer displayed favorable extraction efficiency. The method also showed low limits of detection (0.015-1.412 µg·L-1) and limits of quantitation (0.049-4.707 µg·L-1). Recoveries for all of the herbicides in four different spiked level samples were between 65.06 % and 101.95 % with intra-day and inter-day relative standard deviations less than 9.89 % and 10.54 %, respectively. The proposed MSPE-HPLC-MS/MS method was successfully applied to simultaneously determine 31 amide herbicides in fruit wine.

Antenna-enhanced mid-infrared detection of extracellular vesicles derived from human cancer cell cultures.

BACKGROUND: Extracellular Vesicles (EVs) are sub-micrometer lipid-bound particles released by most cell types. They are considered a promising source of cancer biomarkers for liquid biopsy and personalized medicine due to their specific molecular cargo, which provides biochemical information on the state of parent cells. Despite this potential, EVs translation process in the diagnostic practice is still at its birth, and the development of novel medical devices for their detection and characterization is highly required. RESULTS: In this study, we demonstrate mid-infrared plasmonic nanoantenna arrays designed to detect, in the liquid and dry phase, the specific vibrational absorption signal of EVs simultaneously with the unspecific refractive index sensing signal. For this purpose, EVs are immobilized on the gold nanoantenna surface by immunocapture, allowing us to select specific EV sub-populations and get rid of contaminants. A wet sample-handling technique relying on hydrophobicity contrast enables effortless reflectance measurements with a Fourier-transform infrared (FTIR) spectro-microscope in the wavelength range between 10 and 3 µm. In a proof-of-principle experiment carried out on EVs released from human colorectal adenocarcinoma (CRC) cells, the protein absorption bands (amide-I and amide-II between 5.9 and 6.4 µm) increase sharply within minutes when the EV solution is introduced in the fluidic chamber, indicating sensitivity to the EV proteins. A refractive index sensing curve is simultaneously provided by our sensor in the form of the redshift of a sharp spectral edge at wavelengths around 5 µm, where no vibrational absorption of organic molecules takes place: this permits to extract of the dynamics of EV capture by antibodies from the overall molecular layer deposition dynamics, which is typically measured by commercial surface plasmon resonance sensors. Additionally, the described metasurface is exploited to compare the spectral response of EVs derived from cancer cells with increasing invasiveness and metastatic potential, suggesting that the average secondary structure content in EVs can be correlated with cell malignancy. CONCLUSIONS: Thanks to the high protein sensitivity and the possibility to work with small sample volumes-two key features for ultrasensitive detection of extracellular vesicles- our lab-on-chip can positively impact the development of novel laboratory medicine methods for the molecular characterization of EVs.

µ-FTIR, µ-Raman, and SERS Analysis of Amide I Spectral Region in Oral Biofluid Samples during Orthodontic Treatment.

Gingival crevicular fluid (GCF) is a site-specific exudate deriving from the epithelium lining of the gingival sulcus. GCF analysis provides a simple and noninvasive diagnostic procedure to follow-up periodontal and bone remodeling in response to diseases or mechanical stimuli such as orthodontic tooth movement (OTM). In recent years, the use of vibrational spectroscopies such as Fourier Transform Infrared and Raman microspectroscopy and Surface-Enhanced Raman spectroscopy contributed to characterizing changes in GCF during fixed orthodontic treatment. Amide I band plays a relevant role in the analysis of these changes. The aim of this study was to investigate the spectroscopy response of Amide I depending on the OTM process duration. A model based on Gaussian-Lorentzian curves was used to analyze the infrared spectra, while only Lorentzian functions were used for Raman and SERS spectra. Changes induced by the OTM process in subcomponents of the Amide I band were determined and ascribed to secondary structure modification occurring in proteins. The vibrational spectroscopies allow us to efficiently monitor the effects of the orthodontic force application, thus gaining increasing attention as tools for individual patient personalization in clinical practice.

Gelatin extracted from jundiá skin (Rhamdia quelen): An alternative to the discarded by-product.

The production of gelatin from by-products of the fishing industry values ​​the discarded raw material and serves a part of the population that does not consume products originating from mammals. Therefore, the objective of the research was to use the jundiá skin (Rhamdia quelen) (JS) to obtain gelatin (GJS) and characterize this product, not yet studied until the present moment. Thus, the extraction process showed a yield of 7.3 % for JS and 18.2 % for GJS (in wet weight). Both JS and GJS presented, in their composition, high concentration of protein (26.3 and 88.1 %), low levels of fixed mineral residue (1.0 and 1.9 %), lipids (1.7 and 1.5 %) and hydroxyproline content (1.5 and 7.2 %), respectively. The GJS dispersion had a pH value of 4.7 and the color analysis indicated a snow effect with a white appearance. Fourier transform infrared spectroscopy (FTIR) showed amide bands commonly found in gelatin, gel electrophoresis (SDS-PAGE) showed high molecular weight bands, differential scanning calorimetry (DSC) revealed a denaturation temperature of 69.4 °C and scanning electron microscopy (SEM) showed a compact and non-porous structure. The emulsifying property was high when subjected to a temperature of 80 °C for 30 min, while the foaming capacity was significant at a concentration of 1 %. The highest dispersivity was observed at pH 2.0 and, in this condition, the viscosity was higher than that of other gelatin sources (25.5 cP). In view of the above, attention is drawn to the use of JS as a raw material for obtaining gelatin and for the various possibilities of application.

Nontarget analysis and characterization of alkylamides in electrical product plastics by gas chromatography-positive chemical ionization quadrupole-orbitrap high-resolution mass spectrometry and quasi-molecular ion screening and anchoring algorithm.

Alkylamides are used as plastic additives in various materials and products, potentially posing risks to human health and the environment. Besides reported alkylamides in plastics, many unknown alkylamides may exist in various plastics, which are needing identification and characterization. This study performed nontarget analysis of alkylamides in electrical product plastics by gas chromatography-positive chemical ionization high-resolution mass spectrometry in full scan mode and an in-house developed data-processing algorithm. The algorithm was based on exact mass discrepancies and signal intensities of specific fragment and adduct ions of alkylamides, and was able to efficiently screen and anchor quasi-molecular ions. As a whole, 36 alkylamides were identified, of which 7 were found in all the plastics and 14 were observed in ≥ 2 plastics. The content distributions were elucidated with normalized abundances of quasi-molecular ions of alkylamides. Oleamide showed chromatographic peaks with the highest abundances in individual samples and was the most abundant alkylamide in all the plastics, of which the normalized abundances accounted for 57.42-70.06% of the total abundances of all alkylamides. Besides, (2E)-2-hexenamide, palmitamide and stearamide showed relatively high abundances, of which the relative abundances were 6.99-25.79%. The high abundances together with predicted environmental behaviors and toxicities indicate that alkylamides in plastics are worthy of further in-depth research. The nontarget analysis method including the instrumental analysis and data-processing algorithm can be applied to identification and characterization of alkylamides in more diverse matrices. In addition, the analysis results for the first time provide knowledge about the specific characteristics and relative content distributions of alkylamides in electrical product plastics from a comprehensive perspective.

Ferrous sulfate efficiently kills Vibrio parahaemolyticus and protects salmon sashimi from its contamination.

The primary seafood-borne pathogen Vibrio parahaemolyticus seriously threats the health of consumers preferring raw-fish products, becoming a global concern in food safety. In the present study, we found ferrous sulfate (FeSO4), a nutritional iron supplement, could efficiently induce the death of V. parahaemolyticus. Further, the bactericidal mechanisms of FeSO4 were explored. With a fluorescent probe of Fe2+, a significant influx of Fe2+ was determined in V. parahaemolyticus exposed to FeSO4, and the addition of an intracellular Fe2+ chelator was able to block the cell death. This suggested that cell death in V. parahaemolyticus induced by FeSO4 was dependent on the influx of Fe2+. It was intriguing that we did not observe the eruption of reactive oxygen species (ROS) and lipid hydroperoxides by Fe2+, but the application of liproxstatin-1 (a ferroptosis inhibitor) significantly modified the occurrence of cell death in V. parahaemolyticus. These results suggested FeSO4-induced cell death in V. parahaemolyticus be a ferroptosis differing from that in mammalian cells. Through transcriptome analysis, it was discovered that the exposure of FeSO4 disturbed considerable amounts of gene expression in V. parahaemolyticus including those involved in protein metabolism, amide biosynthesis, two-component system, amino acid degradation, carbon metabolism, citrate cycle, pyruvate metabolism, oxidative phosphorylation, and so on. These data suggested that FeSO4 was a pleiotropic antimicrobial agent against V. parahaemolyticus. Notably, FeSO4 was able to eliminate V. parahaemolyticus in salmon sashimi as well, without affecting the color, texture, shearing force, and sensory characteristics of salmon sashimi. Taken together, our results deciphered a unique ferroptosis in V. parahaemolyticus by FeSO4, and highlighted its potential in raw-fish products to control V. parahaemolyticus.

Comparison of collagen features of distinct types of caries-affected dentin.

OBJECTIVES: To compare the biodegradability, mechanical behavior, and physicochemical features of the collagen-rich extracellular matrix (ECM) of artificial caries-affected dentin (ACAD), natural caries-affected dentin (NCAD) and sound dentin (SD). METHODS: Dentin specimens from human molars were prepared and assigned into groups according to the type of dentin: ACAD, NCAD, or SD. ACAD was produced by incubation of demineralized SD with Streptococcus mutans in a chemically defined medium (CDM) with 1% sucrose for 7 days at 37 °C under anaerobic conditions. Specimens were assessed to determine collagen birefringence, biodegradability, mechanical behavior, and chemical composition. Data were individually processed and analyzed by ANOVA and post-hoc tests (α = 0.05). RESULTS: CDM-based biofilm challenge reduced loss, storage, and complex moduli in ACAD (p < 0.001), while the damping capacity remained unaffected (p = 0.066). Higher red and lower green birefringence were found in ACAD and NCAD when compared with SD (p < 0.001). Differently to ACAD, SD and NCAD presented higher biodegradability to exogenous proteases (p = 0.02). Chemical analysis of the integrated areas of characteristic bands that assess mineral quality (carbonate/phosphate and crystallinity index), mineral to matrix (phosphate/amide I) and post-translational modifications (amide III/CH2, pentosidine/CH2, and pentosidine/amide III) (p<0.05) showed that NCAD was significantly different from SD while ACAD exhibited intermediate values. CONCLUSIONS: CDM-based biofilm challenge produced a dentin ECM with decreased mechanical properties and increased collagen maturity. The compositional and structural conformation of the ACAD suggested that CDM-based biofilm challenge showed potential to produce artificial lesions by revealing a transitional condition towards mimicking critical features of NCAD. CLINICAL SIGNIFICANCE: This study highlights the importance of developing a tissue that mimics the features of natural caries-affected dentin ECM for in vitro studies. Our findings suggested the potential of a modified biofilm challenge protocol to produce and simulate a relevant substrate, such as caries-affected dentin.

Determination of main alkylamides responsible for Zanthoxylum bungeanum pungency through quantitative analysis of multi-components by a single marker.

The pungency of Chinese pepper (Zanthoxylum bungeanum) is mainly attributed to the alkylamides contained therein. However, the quantitation and application of these alkylamides are hindered by the lack of commercially available standards. Herein, five alkylamides mainly responsible for the pungency of Z. bungeanum were quantified in 31 batch samples of this plant by high-performance liquid chromatography-mass spectrometry and quantitative analysis of multi-components by a single marker (QAMS) to reveal significant differences in composition distribution according to the sample source. The two methods employed for this purpose, namely an external standard method and QAMS, were shown to be consistent, as the corresponding standardized mean difference was below 5.0%. Thus, the developed QAMS method was concluded to be a promising alternative for the comprehensive and effective quality control of Z. bungeanum from different sources.