Discovery of inhibitors against mycobacterium branched-chain amino acid aminotransferases through in silico screening and experimental evaluation.

Tuberculosis (TB) is one of the most dangerous infectious diseases and is caused by Mycobacterium bovis (Mb) and Mycobacterium tuberculosis (Mt). Branched-chain amino acid aminotransferases (BCATs) were reported to be the key enzyme for methionine synthesis in Mycobacterium. Blocking the methionine synthesis in Mycobacterium can inhibit the growth of Mycobacterium. Therefore, in silico screening of inhibitors can be a good way to develop a potential drug for treating TB. A pyridoxal 5'-phosphate (PLP)-form of Mycobacterium bovis branched-chain amino acid aminotransferases (MbBCAT), an active form of MbBCAT, was constructed manually for docking approximately 150 000 compounds and the free energy was calculated in Autodock Vina. The 10 compounds which had the highest affinity to MbBCAT were further evaluated for their inhibitory effects against MbBCAT. Within the selected compounds, compound 4 (ZINC12359007) was found to be the best inhibitor against MbBCAT with the inhibitory constant Ki of 0·45 µmol l-1 and IC50 of 2·37 µmol l-1 . Our work provides potential candidates to develop effective drugs to prevent TB since the well-known structural information would be beneficial in the structure-based modification and design.

Single-incision endoscopic-assisted temporoparietal fascia harvest for single stage auricular reconstruction.

INTRODUCTION: The temporoparietal fascia flaps (TPFF) have been widely used to cover the framework in auricular reconstructions. However, flap harvesting is mostly done by open surgery which may be easier but often results in bad scarring and hair loss. We would like to present a series of cases using endoscopic-assisted flap harvesting techniques with only one single cosmetic auricular incision. PATIENTS AND METHODS: Prospective studies from June 2018 to September 2021 on patients who underwent single-stage total auricular reconstruction using autologous costal cartilage and porous polyethylene (PPE) framework. Variables include age, gender, flap survivability as well as visual results and complications. RESULTS: A total of 61 TPFFs were harvested to cover 15 autologous costal cartilages and 46 PPE frameworks in 60 patients (one patient had operation on both sides). TPFF harvests are performed by endoscopic techniques with one single auricular incision. There was no flap necrosis, no bleeding and no cases required framework removal. Only 7/61 (11.5%) ears had small framework exposure which resolved on their own or only required local skin flap coverage and 1 ear had frontal nerve injury. CONCLUSION: Single-stage auricular reconstruction is a difficult surgery, yet greatly beneficial to young children. Through a single-incision endoscopic technique, we can obtain sufficiently large high-survivability TPFFs ensuring full coverage of the autologous costal cartilage or PPE framework. This method is reliable, and reproducible with advanced training. After reviewing the literature, we can state that our report probably includes the largest endoscopic-assisted TPFF harvesting series and the first to implement single-incision endoscopic technique in auricular reconstructions.

Protective efficacy of phage PVN02 against haemorrhagic septicaemia in striped catfish Pangasianodon hypophthalmus via oral administration.

Haemorrhagic septicaemia caused by Aeromonas hydrophila in striped catfish (Pangasianodon hypophthalmus) is one of the most important aquatic diseases in the Mekong Delta, Vietnam. However, antibiotic-resistant A. hydrophila strains have become popular and resulted in inadequate control of the disease in striped catfish farms. This study investigates the protective efficacy of bacteriophage PVN02 against haemorrhagic septicaemia in striped catfish via oral administration. The phage-containing pellets were prepared by spraying the phage solution on food pellets at 20 ml/kg. The rate of phage desorption from the food pellets into the water was very low; the phage titres in the water were approximately log 1.0 PFU/ml or undetectable. The in vivo experiment evaluating the protective efficacy of PVN02 against haemorrhagic septicaemia in striped catfish was conducted using 21 groups of 1,260 fish in 50-L plastic tanks in triplicate. The catfish were fed twice daily with phage-sprayed pellets. Different densities of bacterial suspensions were added into the tanks for 24 hr. Without the existence of the phage, the highest mortality rate was 68.3 ± 2.9% at the highest density of bacterial suspension. In contrast, the mortality rate at the highest density of bacterial suspension was significantly reduced to 8.33 ± 2.9% or 16.67 ± 2.9% at the phage dose of log 6.2 ± 0.09 or log 4.2 ± 0.09 PFU/g. This study provides a very practical manner of applying phage therapy to prevent disease in large-scale striped catfish farms.

Luminescent Ink Based on Upconversion of NaYF4:Er,Yb@MA Nanoparticles: Environmental Friendly Synthesis and Structural and Spectroscopic Assessment.

NaYF4:Er,Yb upconversion luminescent nanoparticles (UCNPs) were prepared by hydrothermal methods at 180 °C for 24 h. The X-ray diffraction (XRD) and TEM (transmission electron microscopy) images show that the resulting 60 nm UCNPs possess a hexagonal structure. In this work, maleic anhydride (MA) was grafted on the surface of UCNPs to induce hydrophilic properties. The photoluminescence spectra (PL) show upconversion emissions centered around 545 nm and 660 nm under excitation at 980 nm. The luminescent inks, including UCNPs@MA, polyvinyl alcohol (PVA), deionized water (DI), and ethylene glycol (EG), exhibit suitable properties for screen printing, such as high stability, emission intensity, and tunable dynamic viscosity. The printed patterns with a height of 5 mm and a width of 1.5 mm were clearly observed under the irradiation of a 980 nm laser. Our strategy provides a new route for the controlled synthesis of hydrophilic UCNPs, and shows that the UCNPs@MAs have great potential in applications of anti-counterfeiting packing.

Impact of Daptomycin Dose Exposure Alone or in Combination with ß-Lactams or Rifampin against Vancomycin-Resistant Enterococci in an In Vitro Biofilm Model.

Enterococcus faecium strains are commonly resistant to vancomycin and ß-lactams. In addition, E. faecium often causes biofilm-associated infections and these infections are difficult to treat. In this context, we investigated the activity of dosing regimens using daptomycin (DAP) (8, 10, 12, and 14 mg/kg of body weight/day) alone and in combination with ceftaroline (CPT), ampicillin (AMP), ertapenem (ERT), and rifampin (RIF) against 2 clinical strains of biofilm-producing vancomycin-resistant Enterococcus faecium (VREfm), namely, strains S447 and HOU503, in an in vitro biofilm model. HOU503 harbors common LiaS and LiaR substitutions, whereas S447 lacks mutations associated with the LiaFSR pathway. MIC results demonstrated that both strains were susceptible to DAP and resistant to CPT, AMP, ERT, and RIF. The 168-h pharmacokinetic/pharmacodynamic (PK/PD) CDC biofilm reactor models (simulating human antibiotic exposures) were used with titanium and polyurethane coupons to evaluate the efficacy of antibiotic combinations. DAP 12 and 14 achieved bactericidal activity against S447 but lacked such effect against HOU503. Addition of ERT and RIF enhanced DAP activity, allowing DAP 8 and 10 plus ERT or RIF to produce bactericidal activity against both strains at 168 h. While DAP 8 and 10 plus CPT improved killing, they did not reach bactericidal reduction against S447. Combination of AMP, CPT, ERT, or RIF resulted in enhanced and bactericidal activity for DAP against HOU503 at 168 h. Our data provide further support for the use of combinations of DAP with AMP, ERT, CPT, and RIF in infections caused by biofilm producing VREfm. Further research involving DAP combinations against biofilm-producing enterococci is warranted.

Unusual Polyhydroxylated Steroids from the Starfish Anthenoides laevigatus, Collected off the Coastal Waters of Vietnam.

Four new polyhydroxylated steroids 1-4 were isolated along with two previously known related steroids 5 and 6 from the methanolic extract of the starfish Anthenoides laevigatus collected off the coastal waters of Vietnam. Structures of new compounds were substantially elucidated by one-dimensional (1D) and two-dimensional (2D) NMR spectroscopy and HRESIMS techniques. Heptaol 1 and hexaol 2 contain the common 5α-cholestane skeleton, while hexaol 3 and heptaol 4 have the rare among starfish steroid compounds 5ß-cholestane skeleton. Compounds 1, 5, and 6 do not show cytotoxic effects against normal JB6 Cl41 and cancer HT-29 and MDA-MB-231 cells, however they inhibit cell proliferation and colony formation of cancer HT-29 and MDA-MB-231 cells.

Negative ion cleavages of (M-H)- anions of peptides. Part 3. Post-translational modifications.

It is now 25 years since we commenced the study of the negative-ion fragmentations of peptides and we have recently concluded this research with investigations of the negative-ion chemistry of most post-translational functional groups. Our first negative-ion peptide review (Bowie, Brinkworth, & Dua, 2002) dealt with the characteristic backbone fragmentations and side-chain cleavages from (M-H)- ions of underivatized peptides, while the second (Bilusich & Bowie, 2009) included negative-ion backbone cleavages for Ser and Cys and some initial data on some post-translational groups including disulfides. This third and final review provides a brief summary of the major backbone and side chain cleavages outlined before (Bowie, Brinkworth, & Dua, 2002) and describes the quantum mechanical hydrogen tunneling associated with some proton transfers in enolate anion/enolate systems. The review then describes, in more depth, the negative-ion cleavages of the post-translational groups Kyn, isoAsp, pyroglu, disulfides, phosphates, and sulfates. Particular emphasis is devoted to disulfides (both intra- and intermolecular) and phosphates because of the extensive and spectacular anion chemistry shown by these groups. © 2016 Wiley Periodicals, Inc. Mass Spec Rev.

Prognostic significance of genetic biomarkers in isocitrate dehydrogenase-wild-type lower-grade glioma: the need to further stratify this tumor entity - a meta-analysis.

The clinical outcomes of isocitrate dehydrogenase-wild-type (IDH-wt) lower-grade glioma (LGG) have been the subject of debate for some time. In this meta-analysis, we aimed to assess the prognostic values of several known genetic markers (e.g. TERT promoter mutation, H3F3A mutation, CDKN2A loss) in this tumor group. Four electronic databases, including PubMed, Scopus, Web of Science and Virtual Health Library, were searched for relevant articles. Pooled hazard ratio (HR) and corresponding 95% confidence interval (CI) for overall survival were calculated using a random-effect model weighted by an inverse variance method. A total of 11 studies were finally selected from 2274 articles for meta-analyses. Several genetic alterations were demonstrated to have a negative impact on prognosis of IDH-wt LGGs, specifically TERT promoter mutation (HR, 1.96; 95% CI, 1.42-2.70), H3F3A mutation (HR, 3.21; 95% CI, 1.86-5.55) and EGFR amplification (HR, 1.67; 95% CI, 1.02-2.74). However, CDKN loss, ATRX mutation and coexisting gain of chromosome 7/loss of chromosome 10 showed no clinical significance in this glioma entity. Our study results demonstrated that IDH-wt LGGs are heterogeneous in clinical outcome and not all tumors have a poor prognosis. The presence of TERT promoter mutation, H3F3A mutation and EGFR amplification showed negative prognostic impacts in this tumor entity. These genetic events can be used to better stratify patient outcomes.

A virome from ornamental flowers in an Australian rural town.

Samples of leaves exhibiting symptoms resembling those caused by virus infection were collected from ornamental street flowers in a rural town in Western Australia. Thirty-seven leaf samples were collected from plants of iris, tulip, lily, daffodil, stock and grape hyacinth. Shotgun sequencing of cDNA derived from leaf samples was done, and analysis showed that about 6% of the sequences obtained were of viral origin. Assembly of virus-like sequences revealed complete or partial genome sequences of 13 virus isolates representing 11 virus species. Eight of the isolates were of potyviruses, one was of a macluravirus, three were of potexviruses, and one was of a bunya-like virus. The complete genome of an isolate originally classified as ornithogalum mosaic virus was genetically divergent and differed in polyprotein cleavage motifs, and we propose that this isolate represents a distinct species. The implications of importing to Australia live plant propagules infected with viruses are discussed.

Correction to: Common findings of blaCTX-M-55-encoding 104-139 kbp plasmids harbored by extended-spectrum ß-lactamase-producing Escherichia coli in pork meat, wholesale market workers, and patients with urinary tract infection in Vietnam.

The original version of this article unfortunately contained a mistake. The legends of Tables 2 and 3, Fig. 1 are incorrect. The corrected legends are given below.

Occurrence of Melibiose-Containing Glycosphingolipids in a Sample of a Sponge-Coral Association (Desmapsamma anchorata/Carijoa riisei).

In our research on biologically active compounds from Vietnamese marine invertebrates, rare melibiose-containing glycosphingolipids were found in a sample of a sponge-coral association (Desmapsamma anchorata/Carijoa riisei). Melibiosylceramides were analyzed as constituents of some multi-component RP-HPLC fractions, and the structures of 14 new (1b, 3b, 4a-4c, 6a-6c, 8b, 9a, 9b, 10b, 11a, 11b) and five known (2b, 5a-5c, 7b) natural compounds were elucidated using NMR, mass spectrometry, optical rotation, and chemical transformations. These α-d-Galp-(1→6)-ß-d-Glcp-(1 ↔ 1)-ceramides (presumably sponge-derived compounds) were shown to contain phytosphingosine-type n-t17:0 (1), (6E)-n-t17:1 (2), i-t17:0 (3), n-t18:0 (4), (6E)-n-t18:1 (5), i-t18:0 (6), (6E)-i-t18:1 (7), i-t19:0 (8), (6E)-i-t19:1 (9), ai-t19:0 (10), and (6E)-ai-t19:1 (11) backbones N-acylated with saturated straight-chain (2R)-2-hydroxy C21 (a), C22 (b), and C23 (c) acids. Characteristic trends in the fragmentations of the terminal parts of tetraacetylated normal-chain and iso- and anteiso-branched sphingoid bases were observed using GC/MS. The total sum of melibiosylceramides and compound 5b caused a reduction in colony formation of human melanoma cells.

Recent trends in the management of pelvic organ prolapse in Australia and New Zealand.

OBJECTIVE: To compare current practice in the management of female pelvic organ prolapse in Australia and New Zealand with that in 2007, and assess the impact on practice of the withdrawal of Prolift® and Prosima® mesh kits in 2015. MATERIALS AND METHODS: In early 2015, two invitations to participate in a survey, including a link to Surveymonkey, were emailed to 2506 Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) trainees and fellows. The online survey closely resembled a printed survey that was posted to RANZCOG trainees and fellows in 2007 and had additional questions relating to the impact of withdrawal of Prolift® and Prosima® products. RESULTS: Four-hundred-and-three doctors participated, giving a response rate of 16%. Native tissue repair was the procedure of choice for primary and recurrent prolapse of the anterior and posterior vaginal wall. An implant was used to treat 45% of anterior recurrences and 25% of posterior recurrences. Vaginal hysterectomy and repair were the procedures of choice for uterovaginal prolapse. Sacrospinous hysteropexy was the uterine preservation procedure of choice, preferred by 41%. For post-hysterectomy vault prolapse, sacrospinous colpopexy and vaginal repair was preferred by 65% of respondents. Between 2007 and 2015, there was a substantial decrease in respondents' usage of implants across all indications except for midurethral slings and sacrocolpo/hysteropexy. Forty-two percent of respondents changed their practice as a result of Prolift® and Prosima® being withdrawn. CONCLUSION: There is a trend toward increasing use of various native tissue prolapse repair procedures and midurethral slings, and less utilisation of transvaginal mesh for prolapse.

Six New Polyhydroxysteroidal Glycosides, Anthenosides S1 - S6, from the Starfish Anthenea sibogae.

Six new polyhydroxysteroidal glycosides, anthenosides S1  - S6 (1 - 6), along with a mixture of two previously known related glycosides, 7 and 8, were isolated from the methanolic extract of the starfish Anthenea sibogae. The structures of 1 - 6 were established by NMR and HR-ESI-MS techniques as well as by chemical transformations. All new compounds have a 5α-cholest-8(14)-ene-3α,6ß,7ß,16α-tetrahydroxysteroidal nucleus and differ from majority of starfish glycosides in positions of carbohydrate moieties at C(7) and C(16) (1 - 4, 6) or only at C(16) (5). The 4-O-methyl-ß-d-glucopyranose residue (2) and Δ24 -cholestane side chain (3) have not been found earlier in the starfish steroidal glycosides. The mixture of 7 and 8 slightly inhibited the proliferation of human breast cancer T-47D cells and decreased the colony size in the colony formation assay.

Impact of High-Level Daptomycin Resistance in the Streptococcus mitis Group on Virulence and Survivability during Daptomycin Treatment in Experimental Infective Endocarditis.

Among the viridans group streptococci, the Streptococcus mitis group is the most common cause of infective endocarditis. These bacteria have a propensity to be ß-lactam resistant, as well as to rapidly develop high-level and durable resistance to daptomycin (DAP). We compared a parental, daptomycin-susceptible (DAPs) S. mitis/S. oralis strain and its daptomycin-resistant (DAPr) variant in a model of experimental endocarditis in terms of (i) their relative fitness in multiple target organs in this model (vegetations, kidneys, spleen) when animals were challenged individually and in a coinfection strategy and (ii) their survivability during therapy with daptomycin-gentamicin (an in vitro combination synergistic against the parental strain). The DAPr variant was initially isolated from the cardiac vegetations of animals with experimental endocarditis caused by the parental DAPs strain following treatment with daptomycin. The parental strain and the DAPr variant were comparably virulent when animals were individually challenged. In contrast, in the coinfection model without daptomycin therapy, at both the 106- and 107-CFU/ml challenge inocula, the parental strain outcompeted the DAPr variant in all target organs, especially the kidneys and spleen. When the animals in the coinfection model of endocarditis were treated with DAP-gentamicin, the DAPs strain was completely eliminated, while the DAPr variant persisted in all target tissues. These data underscore that the acquisition of DAPr in S. mitis/S. oralis does come at an intrinsic fitness cost, although this resistance phenotype is completely protective against therapy with a potentially synergistic DAP regimen.

Imaging of a Thin Oxide Film Formation from the Combination of Surface Reflectivity and Electrochemical Methods.

Electrochemical methods (cyclic voltammetry (CV), potential steps, and electrochemical impedance spectroscopy) were successfully combined with in situ reflectometry measurements for a detailed analysis of the passive layer evolution as a function of the electrode potential. Interestingly, both EIS and surface reflectivity allowed a film thickness in the nanometer range to be readily determined. In addition, transient analyses of the reflectivity simultaneously recorded with CVs show the formation of both Fe2O3 and Fe3O4 oxides. The image analysis showed that the steel surface reactivity is heterogeneous and presents micrometric islands coated with a thicker oxide layer than the surrounding surface. The in situ combination of these techniques thus offers a powerful analytical description of the interface on a local scale and its transient response to a perturbation.

Common findings of bla CTX-M-55-encoding 104-139 kbp plasmids harbored by extended-spectrum ß-lactamase-producing Escherichia coli in pork meat, wholesale market workers, and patients with urinary tract infection in Vietnam.

Extended-spectrum, ß-lactamase-producing Escherichia coli (ESBL-E) harboring the bla CTX-M-55-encoding plasmid (ESBL-E55) has been reported to be associated with urinary tract infection (UTI). The aims of this study were to clarify the prevalence of ESBL-E55 in pork meats and workers from the same wholesale market, as well as patients with UTI from a nearby hospital in Vietnam; we also investigated the plasmids encoding bla CTX-M-55. Sequencing analysis showed that 66.6% of the ESBL-E isolated from pork meats contained bla CTX-M-55, whereas the gene was present in 25.0% of workers and 12.5% of patients with UTI. Plasmid analysis showed that several sizes of plasmid encoded bla CTX-M-55 in ESBL-E55 isolated from pork meats, whereas ESBL-E55 isolated from workers and patients with UTI contained only 104-139 kbp of bla CTX-M-55-encoding plasmids. This indicates that the 104-139 kbp sizes of bla CTX-M-55-encoding plasmids were commonly disseminated in pork meats, wholesale market workers, and patients with UTI.

The identification of disulfides in ricin D using proteolytic cleavage followed by negative-ion nano-electrospray ionization mass spectrometry of the peptide fragments.

RATIONALE: To use negative-ion nano-electrospray ionization mass spectrometry of peptides from the tryptic digest of ricin D, to provide sequence information; in particular, to identify disulfide position and connectivity. METHODS: Negative-ion fragmentations of peptides from the tryptic digest of ricin D was studied using a Waters QTOF2 mass spectrometer operating in MS and MS(2) modes. RESULTS: Twenty-three peptides were obtained following high-performance liquid chromatography and studied by negative-ion mass spectrometry covering 73% of the amino-acid residues of ricin D. Five disulfide-containing peptides were identified, three intermolecular and two intramolecular disulfide-containing peptides. The [M-H](-) anions of the intermolecular disulfides undergo facile cleavage of the disulfide units to produce fragment peptides. In negative-ion collision-induced dissociation (CID) these source-formed anions undergo backbone cleavages, which provide sequencing information. The two intramolecular disulfides were converted proteolytically into intermolecular disulfides, which were identified as outlined above. CONCLUSIONS: The positions of the five disulfide groups in ricin D may be determined by characteristic negative-ion cleavage of the disulfide groups, while sequence information may be determined using the standard negative-ion backbone cleavages of the resulting cleaved peptides. Negative-ion mass spectrometry can also be used to provide partial sequencing information for other peptides (i.e. those not containing Cys) using the standard negative-ion backbone cleavages of these peptides.

Defining daptomycin resistance prevention exposures in vancomycin-resistant Enterococcus faecium and E. faecalis.

Daptomycin is used off-label for enterococcal infections; however, dosing targets for resistance prevention remain undefined. Doses of 4 to 6 mg/kg of body weight/day approved for staphylococci are likely inadequate against enterococci due to reduced susceptibility. We modeled daptomycin regimens in vitro to determine the minimum exposure to prevent daptomycin resistance (Dapr) in enterococci. Daptomycin simulations of 4 to 12 mg/kg/day (maximum concentration of drug in serum [Cmax] of 57.8, 93.9, 123.3, 141.1, and 183.7 mg/liter; half-life [t1/2] of 8 h) were tested against one Enterococcus faecium strain (S447) and one Enterococcus faecalis strain (S613) in a simulated endocardial vegetation pharmacokinetic/pharmacodynamic model over 14 days. Samples were plated on media containing 3× the MIC of daptomycin to detect Dapr. Mutations in genes encoding proteins associated with cell envelope homeostasis (yycFG and liaFSR) and phospholipid metabolism (cardiolipin synthase [cls] and cyclopropane fatty acid synthetase [cfa]) were investigated in Dapr derivatives. Dapr derivatives were assessed for changes in susceptibility, surface charge, membrane depolarization, cell wall thickness (CWT), and growth rate. Strains S447 and S613 developed Dapr after simulations of 4 to 8 mg/kg/day but not 10 to 12 mg/kg/day. MICs for Dapr strains ranged from 8 to 256 mg/liter. Some S613 derivatives developed mutations in liaF or cls. S447 derivatives lacked mutations in these genes. Dapr derivatives from both strains exhibited lowered growth rates, up to a 72% reduction in daptomycin-induced depolarization and up to 6-nm increases in CWT (P<0.01). Peak/MIC and AUC0-24/MIC ratios (AUC0-24 is the area under the concentration-time curve from 0 to 24 h) associated with Dapr prevention were 72.1 and 780 for S447 and 144 and 1561 for S613, respectively. Daptomycin doses of 10 mg/kg/day may be required to prevent Dapr in serious enterococcal infections.

Labile degree of disorder in bismuth-oxophosphate compounds: illustration through three new structural types.

Here, we analyze the crystal structures of three new Bi/M oxophosphates, focusing on the ambiguity between order and disorder in different structural subunits. The three structures are original but systematically built on the assembly of O(Bi,M)4 tetrahedra into various 1D-oxocenterd units, separated by PO4 groups that create cationic channels. Two main subunits show versatile degrees of disorder, i.e., the cationic channels and some of the terminal O(Bi,M)4 entities. (a) In the compound [Bi2(Bi1.56K0.44)(dis)O3]K0.88(dis)(PO4)2, the K/K and K/Bi disorder is total on both nano- and micro-sized domains. (b) In the incommensurately modulated [Bi10(Bi∼0.5Cd∼0.5)8(dis)O16](Bi0.6Cd0.8)2(ord)(PO4)8, only the cationic channels show an ordered Bi/Cd arrangement which can be modified by minor stoichiometric changes between domains. (c) In [Bi18Zn10O21](ord)Zn5(ord)(PO4)14, both subunits are almost perfectly ordered (complex Bi/Zn sequence) into a 7-fold supercell, but this order strongly depends on the observation scale and is mainly lost in micronic-grains also due to slight compositional changes. However, the refined noncentrosymmetric organization is maintained (SHG tests) in the bulk. The relative stability of ordered versus disordered sites is discussed on the basis of the existence of two possible mixed sites and probably depends on the M chemical nature. Disorder was characterized by use of solid-state (31)P NMR probing for the first two cases. Finally, the observed disordered or long periodicities along the infinite dimension suggest the sketch of a periodic/rigid skeleton of O(Bi,M)4 units with counterions filling the interspace in more or less disordered arrangements.

Synthesis and Characteristics of Polymer-Mediated Curcumin Molecular Imprinting for Quantitative Determination of Curcumin in Food Samples.

In this study, a molecularly imprinted polymer (MIP)-based extraction process for determining curcumin in food samples was carried out. MIP and NIP were thermally synthesized in acetonitrile solvent (porogen) using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linking agent, azobisisobutyronitrile as an initiator, and curcumin as a template molecule. Parameters affecting the synthesis process, such as temperature, the ratio of the components in the reaction, and the extraction solvent, were investigated. The characteristics of the synthesized material were examined using infrared spectroscopy and scanning electron microscopy. The maximum adsorption capacity of the material was found to be 1.34 mg/g MIP with an adsorption efficiency of 89.96% for MIP and 12.35% for NIP. The MIP material exhibited high selectivity for curcumin compared to other compounds such as quercetin (18.00%), rutin (14.74%), and ketoconazole (0.00%). The analysis method for curcumin using the MIP material was performed with validated parameters including linear range (1 - 25 mg/L, r2 = 0.9997), accuracy (recovery rate of 90.90 %), precision (RSDR = 0.338 %, RSDr = 1.591 %), detection limit (0.051 mg/L), and quantification limit (0.156 mg/L). The validation results indicated that the HPLC-DAD method was entirely suitable for analyzing the curcumin content in food samples.