Notes

Three-year outcomes of transanal total mesorectal excision compared to regular laparoscopic full mesorectal excision pertaining to mid and occasional anal most cancers.
Quantification of dissolved organic carbon (DOC) and iron (Fe) in surface waters is critical for understanding the water quality dynamics, brownification and carbon balance in the northern hemisphere. Especially in the remote areas, sampling and laboratory analysis of DOC and Fe content at a sufficient temporal frequency is difficult. Ultraviolet-visible (UV-Vis) spectrophotometry is a promising tool for water quality monitoring to increase the sampling frequency and applications in remote regions. The aim of this study was (1) to investigate the performance of an in-situ UV-Vis spectrophotometer for detecting spectral absorbances in comparison with a laboratory benchtop instrument; (2) to analyse the stability of DOC and Fe estimates from UV-Vis spectrophotometers among different rivers using multivariate methods; (3) to compare site-specific calibration of models to pooled models and investigate the extrapolation of DOC and Fe predictions from one catchment to another. This study indicates that absorbances that were measured by UV-Vis sensor explained 96% of the absorbance data from the laboratory benchtop instrument. Among the three tested multivariate methods, multiple stepwise regression (MSR) was the best model for both DOC and Fe predictions. Accurate and unbiased models for multiple watersheds for DOC were built successfully, and these models could be extrapolated from one watershed to another even without site-specific calibration for DOC. However, for Fe the combination of different datasets was not possible.Sirtuin 1 (SIRT1) is an important histone deacetylase that regulates biological functions ranging from DNA repair to metabolism. The alteration of SIRT1 is associated with a variety of diseases including diabetes, inflammation, aging-related diseases, and cancers. Consequently, the detection of SIRT1 activity is of great therapeutic importance. Herein, we demonstrate for the first time the deacetylation-activated construction of single quantum dot (QD)-based nanosensor for sensitive SIRT1 assay. This nanosensor is composed of a Cy5-labeled peptide substrate and a streptavidin-coated QD. The peptide with one lysine acetyl group acts as both the Cy5 fluorophore carrier and the substrate for sensing SIRT1. In the presence of SIRT1, it removes the acetyl group in the acetylated peptide, and the resultant deacetylated peptide can react with the NHS-activated biotin reagent (sulfo-NHS-biotin) to form the biotinylated peptide. The multiple biotinylated peptides can assemble on single QD surface via biotin-streptavidin interaction, inducing efficient fluorescence resonance energy transfer (FRET) from the QD to Cy5, generating distinct Cy5 signal which can be simply quantified by total internal reflection fluorescence-based single-molecule detection. This single QD-based nanosensor can sensitively detect SIRT1 with a detection limit of as low as 3.91 pM, and it can be applied for the measurement of enzyme kinetic parameters and the screening of SIRT1 inhibitors. Moreover, this nanosensor can be used to detect the SIRT1 activity in cancer cells, providing a powerful platform for epigenetic research and SIRT1-targeted drug discovery.The range of applications for aptamers, small oligonucleotide-based receptors binding to their targets with high specificity and affinity, has been steadily expanding. Our understanding of the mechanisms governing aptamer-ligand recognition and binding is however lagging, stymieing the progress in the rational design of new aptamers and optimization of the known ones. Here we demonstrate the capabilities and limitations of native ion mobility-mass spectrometry for the analysis of their higher-order structure and non-covalent interactions. A set of related cocaine-binding aptamers, displaying a range of folding properties and ligand binding affinities, was used as a case study in both positive and negative electrospray ionization modes. Using carefully controlled experimental conditions, we probed their conformational behavior and interactions with the high-affinity ligand quinine as a surrogate for cocaine. The ratios of bound and unbound aptamers in the mass spectra were used to rank them according to their apparent quinine-binding affinity, qualitatively matching the published ranking order. The arrival time differences between the free aptamer and aptamer-quinine complexes were consistent with a small ligand-induced conformational change, and found to inversely correlate with the affinity of binding. This mass spectrometry-based approach provides a fast and convenient way to study the molecular basis of aptamer-ligand recognition.Two types of magnetic hydrophobic solids were prepared by Pickering emulsion photopolymerization using polystyrene-modified magnetic nanoparticles (PS-MNPs) as emulsion stabilizers. Additionally, PS-MNPs provided magnetic character to the final solids. W/O Pickering emulsions were produced with high amounts of oily phase (above 50 wt%), while O/W Pickering emulsions were formed with higher amounts of aqueous phase (above 60 wt%). These two types of emulsions led to two kind of solids with very different structures despite being formed by the same components. In this way, W/O Pickering emulsions produced monolithic solids, while O/W Pickering emulsions formed magnetic microparticles. Multi-walled carbon nanotubes (MWCNTs) were also added to the emulsions to provide higher hydrophobic character to the final solids. The structure and morphology of both magnetic solids containing the MWCNTs was characterized by scanning electron microscopy (SEM). Finally, their extraction efficiency was evaluated using polycyclic aromatic hydrocarbons (PAHs) as target analytes, both qualitatively (visually by the fluorescence emitted before and after the extraction) and quantitatively (using gas chromatography coupled to mass spectrometry). Therefore, the LODs ranged from 1 to 4 μg L-1 and the LOQs were between 3 and 12 μg L-1. The reproducibility of the extraction procedure with different batches of emulsions was acceptable with RSD values less then 13%. Finally, a recovery study was carried out in complex matrices such as chamomile tea, obtaining excellent recovery values which ranged from 99 to 108%.Microporous organic networks (MONs) have shown great promise in separation science recently. Exploring novel, simple and convenient strategy to fabricate MONs coated capillary columns for gas chromatography (GC) still remains challenging but desirable for the development of MONs in chromatographic separation. To extend the potential application of MONs in separation science and to further develop novel method for the fabrication of MONs-based capillary columns, here we demonstrate a novel covalent coupling strategy to fabricate uniform MONs bonded capillary columns for GC separation of position isomers and hydrocarbons. CA The bare capillary column was firstly modified with (3-bromopropyl)trimethoxysilane to provide bromine sites for coupling with alkynyl monomers. The amino- and hydroxyl-functionalized MONs (MON-NH2 and MON-OH) were then directly grown onto the inner wall of the brominated capillary columns via the covalent coupling between bromine and alkynyl groups. The uniform MON-NH2 and MON-OH bonded capillary columns were obtained and showed good resolution for GC separation of dichlorobenzene, chlorotoluene, bromotoluene, and propylbenzene position isomers and many other hydrocarbons including linear alkanes, alkylbenzenes, pinene isomers, cyclohexane and benzene, ketones and aldehydes. The MONs bonded capillary columns also owned good lifetime and precision for dichlorobenzene isomers with the relative standard deviations (RSDs) of 0.2-0.3%, 1.2-2.1%, and 1.7-2.5% for retention time, peak height and peak area, respectively. In addition, the fabricated MON-NH2 and MON-OH bonded capillary columns offered better resolution than commercial InertCap-1, InertCap-5, InertCap-1701 and InertCap-WAX capillary columns for the separation of chlorotoluene and bromotoluene position isomers. These results revealed the feasibility of covalent coupling strategy to fabricate MONs-based stationary phases in GC, highlighting the potential of MONs in separation science.The annual amount of food waste or loss is about one-third of the total edible food globally produced for human consumption. Continuous and real-time monitoring by spoilage detectors can significantly reduce food waste. A novel paper-based pH-sensitive meat spoilage detector was developed. A mixture of soybean hulls (SBHs) (hydrothermally-treated in an acidic environment), bentonite, and bromocresol purple (BCP) was coated on paper to produce the detector. The resultant meat spoilage detector was evaluated as a real-time freshness and spoilage indicator of catfish fillets (Ictalurus punctatus). Freshness and spoilage of fish meat with varying weights and headspace were determined by tailoring the detector's pH. Elemental, structural, and functional analysis verified the formation of a packed SBH-bentonite matrix with enhanced gas adsorption capacity and effective BCP-immobilization. Binder nanofibrillation increased the overall visual color vibrancy and decreased the binder demand in the coating formulation. Headspace volume in the studied range (40 and 160 cm3) did not affect the activation time of the detectors. However, increasing fish weight decreased the detectors' optimum activation time and pH. The findings of this study show that the developed detectors can be tailored for a wide range of sample and packaging sizes by simply adjusting the pH of the detector.Plasticizers are chemical compounds used in the production of flexible plastics for a large variety of applications. They are present in most of the environments and, hence, we are highly exposed to them via several routes (ingestion, inhalation, etc). Due to the endocrine disruption potential of some of these chemicals and the unknown toxicological effects of their alternatives, assessing human exposure to these contaminants is an issue of emerging concern. Herein we propose an analytical methodology for the determination of several plasticizer metabolites in wastewater as a non-invasive, cheap, and fast exposure monitoring tool complementary to the analysis of urine. A solid-phase extraction procedure followed by an ultra(high)-performance liquid chromatography-tandem mass spectrometry method was optimized and validated for 21 analytes among phthalate, terephthalate, and di-iso-nonyl cyclohexane-1,2-dicarboxylate metabolites. Method quantification limits ranged from 0.079 to 4.4 ng L-1. The method was applied to the analysis of seven daily composite wastewater samples collected in the NW of Spain. Metabolites of low molecular weight phthalates and of di-2-ethylhexyl phthalate were quantified in all samples, despite the existing regulations limiting the use of phthalates. Metabolites of terephthalates, introduced at the end of the 20th century as phthalate substituents, were also quantified in all samples, being the first time that they were detected in this matrix. Exposure back-calculation highlighted di-2-ethylhexyl terephthalate as the second most common plastic additive after diethyl phthalate in the population considered, reflecting the increasing substitution of di-2-ethylhexyl phthalate by its analogous terephthalate.
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