Search

1. In order to compare the difference between different derivatisations for amino acids determination of foie gras via, reversed phase high performance liquid chromatography (HPLC), O-phthalaldehyde and 9-fluorenyl-methyl chloroformate (OPA-FMOC group), phenylisothiocyanate (PITC group) and 6-Aminoquinolyl-N-hydrox-ysuccinimidyl Carbamate (AQC group) were applied to derivatisation reagent in this current experiment. The determination results of automatic amino acid analyser were applied, and 17 amino acids were detected by these three derivatisation methods.2. The running times of OPA-FMOC group, PITC group and AQC group were 18, 45 and 35 min, respectively. There was a large difference between the results of OPA-FMOC group and results from the automatic amino acid analyser, although the difference between the results from PITC and the automatic amino acid analyser was minimal.3. In conclusion, the running time of OPA-FMOC group was shorter than that of PITC group and AQC group; the accuracy of the former was better than the OPA-FMOC group and AQC group for the determination of amino acid of foie gras. [ABSTRACT FROM AUTHOR]

We use the mapping between two computation frameworks, Adiabatic Grover Search (AGS) and Adiabatic Quantum Computing (AQC), to translate the Grover search algorithm into the AQC regime. We then apply Trotterization on the schedule-dependent Hamiltonian of AGS to obtain the values of variational parameters in the Quantum Approximate Optimization Algorithm (QAOA) framework. The goal is to carry the optimal behavior of Grover search algorithm into the QAOA framework without the iterative machine learning processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A robust reverse-phase HPLC-MS/MS method was proposed based on AQC derivatization. • This method is capable of separating and detecting hydrophilic amino acids and sphingoid bases in a single run with high sensitivity. • The method was applied to human serum samples for the screening of biomarkers. • Two sphingolipids and five amino acids were identified with significant differences between the control and T2DM groups. Sphingolipids are a major lipid species found in all eukaryotes. Among structurally complex and diversified lipids, sphingoid bases have been heavily linked to various metabolic diseases. However, most current LC-MS-based methods lack the sensitivity to detect low-abundant sphingoid bases. The 6-Aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization reagent, which efficiently forms covalent bonds with amino groups, has been widely used for amino acid detection. Nevertheless, the commonly used reverse-phase HPLC method for amino acid analysis is not suitable for amphipathic sphingolipids. To address this issue, we report a robust reverse-phase HPLC-MS/MS method capable of separating and detecting hydrophilic amino acids and sphingoid bases in a single run with high sensitivity. This method is also inclusive of other amino metabolites with an expandable target list. We tested this method under various conditions and samples, demonstrating its high reproducibility and sensitivity. Using this approach, we systematically analyzed human serum samples from healthy individuals, dyslipidemia, and type II diabetes mellitus (T2DM) patients, respectively. Two sphingolipids and five amino acids were identified with significant differences between the control and T2DM groups, highlighting the potential of this method in clinical studies. [ABSTRACT FROM AUTHOR]

The majority of human proteins operate as multimeric complexes with defined compositions and distinct architectures. How the assembly of these complexes is surveyed and how defective complexes are recognized is just beginning to emerge. In eukaryotes, over 600 E3 ubiquitin ligases form part of the ubiquitin–proteasome system (UPS) which detects structural characteristics in its target proteins and selectively induces their degradation. The UPS has recently been shown to oversee key quality control steps during the assembly of protein complexes. We review recent findings on how E3 ubiquitin ligases regulate protein complex assembly and highlight unanswered questions relating to their mechanism of action. The majority of human proteins function as part of multimeric protein complexes. Subunit stoichiometry in vivo is highly variable, and a significant fraction of the proteome arises from non-stoichiometric synthesis. The ubiquitin–proteasome system (UPS) can detect failures in complex assembly and target unassembled or incorrectly assembled complexes for degradation. Key cellular complexes such as hemoglobin, BTB (broad complex, Tramtrack, and Bric-à-brac) dimers, the proteasome, and the ribosome have recently been shown to undergo assembly quality control (AQC). AQC safeguards cellular function and health. [ABSTRACT FROM AUTHOR]

This bibliography contains journal articles, book chapters, books, edited volumes, theses, grey literature, and other resources, including other bibliographies, on Al-Qaeda and its affiliated organizations. To keep up with rapidly changing political events, the most recent publications have been prioritized during the selection process. The literature has been retrieved by manually browsing more than 200 core and periphery sources in the field of Terrorism Studies. Additionally, full-text and reference retrieval systems have been employed to broaden the search. [ABSTRACT FROM AUTHOR]

Time-resolved imaging by means of single-photon avalanche diodes (SPADs) has achieved widespread interest in recent years, especially since technological progress has opened the way to the development of multichannel time-correlated single-photon counting (TCSPC) acquisition systems. Unfortunately, currently available TCSPC imagers feature relatively low performance with respect to state-of-the-art single-channel systems. A real breakthrough in this field would be the exploitation of large arrays of high-performance SPAD detectors developed by means of dedicated fabrication processes, usually referred to as custom technology. Custom-technology SPADs require external electronics potentially leading to interconnection issues for densely integrated arrays. In this paper, we present a new fully integrated front-end circuit able to provide both quenching/reset and timing functionalities while requiring a single connection toward the SPAD. This is the first fully integrated circuit reported in literature that can provide both the timing information about the photon time of arrival with a jitter as low as 37 ps and apply high-voltage pulses up to 50 V in order to meet the requirements of several detectors, including the new red-enhanced SPAD. Combining these two capabilities in a single circuit strongly reduces the complexity of the connection between an array of custom-technology SPADs and the relative external front end, thus paving the way for the exploitation of high-performance SPADs in TCSPC imaging systems.

Electron‐shuttling molecules (ESMs), natural or synthetic, are utilized by microorganisms as electron acceptors or donors to facilitate electron transfer. In this study, five ESMs, namely anthraquinone‐2‐carboxylic acid (AQC), 9,10‐anthraquinone‐2‐sulfonicacid (AQS), 9,10‐anthraquinone‐2,6‐disulfonic acid (AQDS), Neutral red, and Thionin, were selected to assess their effects on electromethanogenesis under different electrochemical potentials and concentrations. Results showed that the rate of methanogenesis achieved in the presence of AQC was 7.4 times higher than that of the control (without ESMs) at −850 mV (vs. Ag/AgCl). The effectiveness on methanogenesis followed AQC, Neutral Red, AQS, AQDS, and Thionin in a decreasing order. Compared with the control, the addition of ESMs did not affect the biomass of methanogens significantly. Meanwhile, qPCR analysis of the ccdA gene indicated that the abundance of the Cytochrome c gene and the extent of CO2 reduction to methane correlated positively. The promoting effect of the selective ESMs on methanogenesis was mainly related to their electron transfer capabilities. [ABSTRACT FROM AUTHOR]

The protective textiles with multifunctional properties such as pollutants capture, antibacterial property, detoxification, and self-cleaning ability are highly demanded for soldiers, medical staff and field workers. To achieve multifunctional properties while maintaining the wearing comfort of protective textiles remains a challenge. PVA-co-PE nanofiber membrane has found promising applications in filtering particles due to its large specific surface area. However, due to its limited hydrophilicity, the surface functionalization of nanofiber membrane is difficult. Cellulose Nano-Crystals (CNCs) possessing abundant hydroxyl groups were used to modify the surfaces of PVA-co-PE nanofiber membranes to facilitate the surface functionalization. The photoactive substance of AQC was subsequently grafted onto the CNCs modified PVA-co-PE nanofiber membrane. Depending on the surface chemical structures of nanofiber membranes, the AQC on the nanofiber membrane showed different morphologies and ordered structures. The AQC/CNCs functionalized PVA-co-PE nanofiber membrane demonstrated excellent antibacterial property after 5 min UV exposure, as well as the performance of degrading chemicals. Furthermore, the super-hydrophilic property of the functionalized membrane enables the wearing comfort. The super hydrophilic AQC/CNCs functionalized membrane with multi-functions can be widely applied in the protective clothing in the near future. [ABSTRACT FROM AUTHOR]

β- N-Methylamino-L-alanine (BMAA) is a non-canonical amino acid implicated as a cause for amyotrophic lateral sclerosis/parkinsonism dementia complex and potentially other neurodegenerative diseases. As interest in this molecule has increased, there has been a proliferation of methods along with a plethora of opinions as to the superiority of some methods over others. We analyzed the literature with reference to BMAA and its naturally occurring isomers, N-(2-aminoethyl) glycine (AEG) and 2,4 diaminobutyric acid (DAB). A comparison of methods, results, and critiques reveal that a single method has been approved by the AOAC but several different methods provide comparable BMAA quantification concentrations in similar tissues. We also describe a productive way to move forward as technology improves and changes. [ABSTRACT FROM AUTHOR]

Changes in biogenic amines profile during storage of opened wine bottles have been monitored. Three different wine types were selected (standard and high quality red wines and young white wine), and once opened, wine bottles were kept in different storage conditions (temperature and stopper kind). The total concentration of biogenic amines in just opened bottles ranged between 35.4–39.2 mg/L in standard quality red wine; 18.5–22.8 mg/L in high quality red wine; and 5.08 mg/L in bulk young white wine. Both red wines showed higher amounts of histamine and putrescine, whilst the white wine contained tyramine, putrescine and histamine in a similar concentration. Cadaverine presented a similar concentration for all samples (0.25–0.42 mg/L). Methylamine and spermine were not detected in any sample. The results from 36 samples showed that biogenic amines did not increase significantly in any case. Slight changes in the concentration of certain biogenic amines were detected as a result of the different storage conditions. A principal component analysis using biogenic amines as variables allowed to group the different kinds of wine. Linear Discriminant Analyses grouped the three wine types by storage time. Histamine and cadaverine showed a marked positive correlation in all wine types. [ABSTRACT FROM AUTHOR]

• Nutritional supplement containing spermidine and OPC caused analytical phenomenon. • Interestingly, spermidine was partly undetectable in the presence of OPC. • Interfering impact of OPC on the quantification of spermidine and other polyamines. • OPC have a high binding affinity for (pure) spermidine and spermine. • Different spermidine-containing raw materials (wheat, barley, algae) investigated. The impact of oligomeric proanthocyanidins (OPC) on UHPLC analysis of spermidine was investigated because spermidine could not be detected in a commercial nutritional supplement containing both health-enhancing compounds. Therefore, pure spermidine and other raw materials rich in spermidine (wheat germs, barley, algae) were mixed with OPC-containing extracts. Results obtained showed that mixing pure solutions of spermidine with OPC extracts led to a fast and significant reduction in spermidine determined, while mixing other raw materials with OPC extracts resulted in a much slower reduction to a lesser extent. Dwell time hardly influenced the amount of residual spermidine found, while different food matrices might reduce the extent of binding by OPC. Other relevant analytes in polyamine biosynthesis (arginine, ornithine, putrescine and spermine) were also investigated showing only a slight decrease for amino acids and putrescine, whereas especially spermidine and spermine have a higher affinity to be bound by OPC. Thus, the spermidine analysis of OPC-rich food supplements may give dramatically lower levels or even lead to false-negative results. [ABSTRACT FROM AUTHOR]

Highlights: [•] Determination of biogenic amines using SPE and AQC as derivatization agent. [•] The concentration of biogenic amines present in vinegar are much lower than wines. [•] Balsamic and Pedro Ximenez vinegar present the highest amounts of biogenic amines. [•] Methylamine and phenyletylamine are not determined in any vinegar. [•] Red wine vinegars present a different profile of biogenic amines. [Copyright &y& Elsevier]

A simple, sensitive and reproducible high-performance liquid chromatography (HPLC) method has been validated for determining concentrations of glutamate, glycine, and alanine in human plasma. Proteins in plasma were precipitated with perchloric acid, followed by derivatization with 6-aminoquinolyl- N-hydroxysuccinimidyl carbamate (AQC). Simultaneous analysis of glutamate, glycine, and alanine is achieved using reversed-phase HPLC conditions and ultraviolet detection. Excellent linearity was observed for these three amino acids over their concentration ranges with correlation coefficients (r)>0.999. The intra- and inter-day precision were below 10%. This method utilizes quality control samples and demonstrates excellent plasma recovery and accuracy. The developed method has been successfully applied to measure plasma glutamate, glycine, and alanine in twenty volunteers. [ABSTRACT FROM AUTHOR]

Abstract: Fermented foods and beverages contain several different types of dipeptides, which are believed to be important components for taste. To date, however, a method for the comprehensive analysis of dipeptides in these products has not yet been established. In this study, comprehensive analysis of dipeptides in alcoholic beverages was performed by a high-resolution separation method based on the structural characteristics of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC)-derivatized dipeptides as well as dipeptide quantification and structural estimation using ultra-high-pressure liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) and UHPLC-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOFMS), respectively. Dipeptide content was found to differ considerably among Japanese sake, beer, and wine; UHPLC–MS/MS analysis revealed that many types of dipeptides are present in sake. Dipeptide quantification analysis identified 32 types of dipeptides within the concentration range of 1.1–97.2μM in sake. The analysis was validated by dipeptide recovery of 64.0–107.2% (2.5μM of standard) with a relative standard deviation of ≤33.2% from an actual alcoholic sample. Furthermore, UHPLC-Q-TOFMS analysis suggested the existence of more than 35 types of dipeptides in sake. Thus, by the combined analysis methods, we discovered that more than 60 dipeptides are present in sake. This research is the first report of dipeptide profiling of fermented alcoholic beverages by comprehensive analysis. [Copyright &y& Elsevier]

The tailor made amino acid β- N-methyl-amino- l-alanine (BMAA) is a neurotoxin produced by cyanobacteria. It has been associated with certain forms of progressive neurodegenerative disease, including sporadic Amyotrophic Lateral Sclerosis and Alzheimer's disease. Some different reports of BMAA in cyanobacterial blooms from lakes, reservoirs, and other water resources have been made by different investigators. We here report the detection of BMAA of both free and protein-bound produced by cyanobacteria, belonging to the Chroococcales, Oscillatoriales and Nostocales ordered. We use a rapid and sensitive HPLC-FD method that utilizes methanol elution and the Waters AQC Tag chemistry. On other hand, we have used three different assay procedures for BMAA extraction from cyanobacteria: Trichloroacetic acid (TCA), Methanol/Acetone and hydrochloric acid (HCl). All assays let successfully detect BMAA in all cyanobacteria samples analyzed. Nevertheless, with TCA and HCl extraction procedures the highest BMAA values, for free as well as protein-bound BMAA were detected. BMAA content could not be related to the taxonomy of the isolates or to their geographical origin, and no correlation between free and protein-bound BMAA concentrations were observed within or between taxonomic groups. These data offer confirmation of the taxonomic and geographic ubiquity of BMAA from naturally occurring populations of cyanobacteria, for the first time reported for estuaries. [ABSTRACT FROM AUTHOR]

In early 2020, the COVID-19 pandemic spread globally, and severe measures to control it were implemented. This study investigates the impact of the lockdown on the air quality of three provinces in the Valencia region, eastern Spain, in the years 2015–2020, focusing on particulate matter (PM). A thorough statistical analysis using different approaches is conducted. Hourly patterns are also assessed. In addition, the role of meteorological parameters on PM is explored. The results indicate an overall PM10 reduction of 16.5% when comparing the lockdown in 2020 and the 2015–2019 period, while PM2.5 increased by 3.1%. As expected, urban zones experienced higher reductions than suburban zones, which experienced a PM concentration increase. The impact of the drastic drops of benzene, toluene and xylene (77.4%, 58.0% and 61.8%, respectively) on the PM values observed in urban sites is discussed. Our study provides insights on the effect of activity changes over a wide region covering a variety of air quality stations, urban, suburban and rural, and different emission types. The results of this work are a valuable reference and suggest the need for considering different factors when establishing scientific air pollution control strategies. [ABSTRACT FROM AUTHOR]

Abstract: An accurate, rapid and sensitive high-performance liquid chromatographic (HPLC) method is reported for the determination of four biogenic amines in red and white wine samples. The method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) followed by liquid chromatography gradient elution analysis without any other sample pretreatment. The procedure developed permitted the determination of the four amines in 40min. The relative standard deviation (RSD) values ranged from 3.1% to 6.1% in peak areas and the response was linear (R 2 >0.994) in a range from 0.1 to 4mg/l. Leaving aside putrescine in Tempranillo wines, the malolactic fermentation did not exert any effect on the concentration of these compounds. On the contrary, the influence of the grape variety was important, and Tempranillo wines showed higher levels of tyramine and histamine and lesser of putrescine and cadaverine (p <0.05) than wines made with Cabernet Sauvignon. [Copyright &y& Elsevier]

Abstract: The validation of a pre-column derivatization procedure with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) to the determination of the amino acid content by RP-HPLC with fluorescence detection (λ excitation 250nm, λ emission 395nm) in milk-cereal based infant foods was carried out. The analytical parameters: linearity (0.0025–0.2mM), precision of the method (0.2–3.5% variation coefficients), accuracy (derivatization: 86–106% average recovery and method: 88.3–118.2% average recovery) and the limits of detection (0.016–0.367μM) and quantification (0.044–1.073μM) were determined. Glutamic acid, proline and leucine were the most abundant amino acid whereas the lowest contents corresponded to tyrosine and cysteine. [Copyright &y& Elsevier]

• The dominant carotenoid in Chaenomeles fruits is β-carotene. • Chaenomeles fruits contain eight chlorophyll derivatives. • Among the isomers of tocopherols, the α form predominate in Chaenomeles fruit. • L-asparagine accounts for over 55 % of the total amino acid in Chaenomeles fruit. • The content of amino acids is correlated with tocopherols and tocotrienols. This study aimed to identify and quantify carotenoids, chlorophylls, tocopherols, tocotrienols and the free amino acid profile of 19 fruit cultivars of Chaenomeles × superba , Chaenomeles japonica , and Chaenomeles speciosa. For this purpose ultra-performance liquid chromatography (UPLC) with a photodiode array (PDA) and fluorescence (FL) detector coupled with quadrupole time-of-flight electrospray ionization mass spectrometry (QToF–ESI–MS) was used. Most of the Chaenomeles species and cultivars analyzed in this study have not been examined in this respect until now. Fruits contained 32.44–314.94 mg of carotenoids, 19.27–227.19 mg of chlorophylls, 5.51–37.58 mg of tocopherols, and 2.06–42.30 mg of tocotrienols per kg of dry weight (dw). Analysis of the amino acid profile revealed the presence of 10 amino acids, three of them essential (l -threonine, l -valine and l -isoleucine). The highest content of total amino acids was shown by C. × superba ˈJet Trailˈ (2326.33 mg/100 g dw). Among tested species, C. speciosa was characterized by the highest content of all analyzed compounds, except for chlorophylls, present in the highest concentration in C. × superba fruits. These results indicate that Chaenomeles fruits could be regarded as a promising source of bioactive functional food containing vitamins A and E and indispensable amino acids. [ABSTRACT FROM AUTHOR]