Deprecated: bp_before_xprofile_cover_image_settings_parse_args is deprecated since version 6.0.0! Use bp_before_members_cover_image_settings_parse_args instead. in /home/top4art.com/public_html/wp-includes/functions.php on line 5094
  • Gonzales Schulz posted an update 4 days, 11 hours ago

    Analysis of the ATR-FTIR spectra from the band at RF = 0.85 that inhibits α-amylase, suggests that fatty acid esters are responsible for the enzyme inhibition; both saturated fatty acid esters in unfermented extracts and unsaturated fatty acid esters in fermented extracts. The ATR-FTIR spectra of the polyphenolics in fermented extracts (RF = 0.15-0.20) suggests the presence of soluble lignin fragments (i.e. lignins depolymerized into monomers and oligomers during the fermentation process).Tetrabromobisphenol-A and Tetrabromobisphenol-S (TBBPA/S) and their derivatives have attracted widespread attention owing to their environmental risks and adverse effects on human health. In this study, we developed an analytical method based on ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of TBBPA/S and their eight derivatives in soil samples. After ultrasonic extraction, TBBPA/S and their derivatives were purified using an LC-Si cartridge with 1 mL acetone and 30 mL dichloromethane/n-hexane (1/1, v/v) as the eluent. In the multiple reaction monitoring (MRM) mode, TBBPA and TBBPS were quantified with electrospray ionization (ESI), whereas their derivatives were quantified with atmospheric pressure chemical ionization (APCI). The proposed method was verified with blank spiking and matrix spiking experiments. All target compounds were recovered at the range of 78-124% and the average recoveries of surrogate standard 13C12-labeled TBBPA were 103% and 99% in spiked blank and soil samples, respectively. The method quantitative limits (MQLs) of TBBPA/S and their derivatives in soil samples ranged from 0.22 to 8.8 pg/g dw. These results indicated that an effective method was provided for the analysis of TBBPA/S and their derivatives in abiotic matrices.Drug-induced phospholipidosis (DIPLD) represents a big concern for both regulatory authorities and pharmaceutical companies in drug discovery. CB-839 Glutaminase inhibitor Many researches pointed out that the negatively charged intralysosomal lipids play an important role in the formation of DIPLD. To better mimic this negatively charged lipid surface, a novel immobilized artificial membrane (IAM) column was prepared via in situ copolymerization of 12-methacryloyl n-dodecylphosphocholine (MDPC) and 12-methacryloyl n-dodecylphosphoric acid (MDPA). By introducing MDPA, the surface of the resulting monolithic column can be maintained negatively charged over a broad pH range. Scanning electron microscopy, elemental analysis and nano-HPLC experiments were carried out to characterize the physicochemical properties and chromatographic performance of the obtained monolithic IAM column. The results of ζ-potential and retention mechanism studies indicate that both hydrophobic and electrostatic interactions contribute greatly to the retention of cation analytes owing to the existence of the negatively charged MDPA under acidic conditions. To better assess the DIPLD potency of drug, the molar ratio between MDPC and MDPA in the monolithic column was carefully optimized. The results show that the poly(MDPC70PA30-co-EDMA) column has the best predictability with only two false-positives (donepezil, flecainide) in qualitative analysis of 61 drugs.Molecularly imprinting polymers with high selectivity toward 29 sulfonylurea herbicides were synthesized by precipitation polymerization, using metsulfuron-methyl and chlorsulfuron as the template molecule, 4-vinylpyridine as the function monomer, divinylbenzene as the crosslinking agent, and acetonitrile as porogen. The imprinted polymers were characterized and measured by scanning electron microscopy (SEM) and equilibrium adsorption experiments. The molecularly imprinted polymers displayed specific recognition for the tested 29 sulfonylurea herbicides, and the maximum apparent binding capacity was found to be 18.81 mg/g. The synthesized polymer was used as a solid-phase extraction (SPE) column coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination of the tested analytes in agro-products. Within the range of 2-100 μg/L, the tested analytes have achieved a good linear association with correlation coefficient (R2) > 0.999. The calculated limits of detection (LODs, S/N=3) as along with limits of quantification (LOQs, S/N=10) were in the ranges of 0.005-0.07 μg/L and 0.018-0.23 μg/L, respectively. Under different spiking levels, the recovery rates were ranged from 74.8% – 110.5%, and the relative standard deviation (RSDs) were less then 5.3%. Finally, the feasibility of the proposed methodology was successfully applied for detection of sulfonylurea herbicides in crops, vegetables, and oils samples.The toolbox of medicinal chemists includes the 1,4-benzodiazepine scaffold as a “privileged scaffold” in drug discovery. Several biologically active small molecules containing a 1,4-benzodiazepine scaffold have been approved by the FDA for the treatment of various diseases, with most of them being used for their psychotropic effects. The therapeutic potential of 1,4-benzodiazepines has stimulated the interest of synthetic chemists in developing new synthetic strategies to a range of substituted analogues for biological evaluation. A structural variation of the classical benzodiazepine skeleton is observed e.g. in alprazolam, midazolam, and related benzodiazepines, which contain a 1,2,4-triazole or an imidazole ring fused to the benzodiazepine core. Irrespective of the presence of the fused heterocyclic ring, the seven-membered diazepine ring is far from planar, and its shape resembles a twist chair. Then, the unsymmetrical substitution pattern around the seven membered cycle renders these molecules chiral, asthe dynamic HPLC investigations carried out on a set of fused imidazo and triazolo-benzodiazepines (alprazolam, midazolam, triazolam and estazolam) The experimental dynamic chromatograms and the corresponding interconversion barriers reported in this paper show that the third fused heterocyclic ring increase the energy barrier by 2 kcal/mol.Hydrophilic column combined with mobile phase containing high content of water is a green method for the separation of polar compounds, but there are few related studies, and the separation efficiency and performance of existing columns still needs to be improved. In this work, a novel monolithic column for separation of hydrophilic compounds under both high water content and HILIC condition, was prepared by in-situ polymerization using 4-vinylbenzoic acid (VBA) and 1-(Acryloyloxy)-3-(methacryloyloxy)-2-propanol (AMAP) as functional monomers. The poly(VBA-co-AMAP) monolithic column showed good separation performance towards various polar compounds under different chromatographic conditions based on the π-interaction, hydrophobic and hydrogen bonding interactions provided by 4-vinylbenzoic acid functional monomer. The highest column efficiency for adenine was over 2.15 × 105 plates m-1 (theoretical plate, N). In addition, the monolith showed good stability and reproducibility, the relative standard deviations (RSDs) of retention times within days (n = 5), between days (n = 5), between columns (n = 3) and between batches (n = 3) were 0.

Facebook Pagelike Widget

Who’s Online

Profile picture of Waddell Jepsen
Profile picture of Ratliff Strand
Profile picture of Bryant Burton
Profile picture of Thuesen Thestrup
Profile picture of Chris Oyakhilome
Profile picture of palermo2
Profile picture of Nordentoft Mohr
Profile picture of Greve Gottlieb
Profile picture of Lamm Myrick
Profile picture of Willoughby Banke
Profile picture of Snow Clements