Role of human flavin-containing monooxygenase (FMO) 5 in the metabolism of nabumetone: Baeyer-Villiger oxidation in the activation of the intermediate metabolite, 3-hydroxy nabumetone, to the active metabolite, 6-methoxy-2-naphthylacetic acid in vitro.

Nabumetone (NAB) is a non-steroidal anti-inflammatory drug used clinically, and its biotransformation includes the major active metabolite 6-methoxy-2-naphthylacetic acid (6-MNA). One of the key intermediates between NAB and 6-MNA may be 3-hydroxy nabumetone (3-OH-NAB). The aim of the present study was to investigate the role of flavin-containing monooxygenase (FMO) isoform 5 in the formation of 6-MNA from 3-OH-NAB. To elucidate the biotransformation of 3-OH-NAB to 6-MNA, an authentic standard of 3-OH-NAB was synthesised and used as a substrate in an incubation with human liver samples or recombinant enzymes. The formation of 3-OH-NAB was observed after the incubation of NAB with various cytochrome P450 (CYP) isoforms. However, 6-MNA itself was rarely detected from NAB and 3-OH-NAB. Further experiments revealed a 6-MNA peak derived from 3-OH-NAB in human hepatocytes. 6-MNA was also detected in the extract obtained from 3-OH-NAB by a combined incubation of recombinant human FMO5 and human liver S9. We herein demonstrated that the reaction involves carbon-carbon cleavage catalyzed by the Baeyer-Villiger oxidation (BVO) of a carbonyl compound, the BVO substrate, such as a ketol, by FMO5. Further in vitro inhibition experiments showed that multiple non-CYP enzymes are involved in the formation of 6-MNA from 3-OH-NAB.

Photolysis and photocatalysis of tetracycline by sonochemically heterojunctioned BiVO4/reduced graphene oxide under visible-light irradiation.

The widespread use of antibiotics in pharmaceutical therapies and agricultural practice has led to severe environmental pollution. In this study, the simultaneous photolysis and photocatalysis behaviors of tetracycline (TC), one of the most frequently prescribed groups of antibiotics, were investigated using BiVO4 (BVO) supported on reduced graphene oxide (rGO). The resulting BVO/rGO nanocomposite (NC) showed prominent adsorption performance and photocatalytic ability under wide initial pH conditions (from acidic to alkaline: pH 2.5, 6.7, 9.2 and 10.5). This study analyzed the kinetics and proposed a mechanism for the photolytic and photocatalytic degradation of TC under visible light irradiation with BVO and BVO/rGO. The photolysis and photocatalytic degradation efficiency of TC was largely influenced by the solution pH and increased with increasing initial pH. The TC was stable without significant photolysis at pH 2.5, while TC photolysis increased up to 17% at pH 9.2. With further increase in the solution pH from 9.2 to 10.5, the light absorption of TC at 356 nm showed a red shift to 372 nm and new absorption peaks at around 533 nm were formed due to the formation of new colored intermediates. The photocatalytic degradation activities of TC by BVO/rGO under visible light irradiation reached 55, 67, 92 and 99% at initial pH 2.5, 6.7, 9.2 and 10.5, respectively. However, when using BVO only, the photocatalytic degradation of TC was 42, 61, 73 and 85% at pH 2.5, 6.7, 9.2 and 10.5, respectively. The great improvement of photocatalytic activity of BVO/rGO is attributed to the reduced particle size, increased adsorption ability of rGO, extended photo responding range of BVO, and efficient separation of photogenerated charge carriers, which are derived from the ultimate coverage of the BVO by the rGO.

NiFe-bimetal-organic framework grafting oxygen-vacancy-rich BiVO4 photoanode for highly efficient solar-driven water splitting.

Bismuth vanadate (BVO) possesses great potential in photoelectrochemical water splitting application, but still suffers from low charge transfer efficiency as well as poor chemical stability. Herein, we have fabricated a thin NiFe-bimetal-organic framework (NiFe-MOF) layer grafting surface oxygen vacancies enriched BVO photoanode (NiFe-Ovac-BVO), which improves the charge separation and transfer efficiency during oxygen evolution process. Meanwhile, the NiFe-MOFs thin layer can not only protect the surface Ovac of BVO, but also efficiently inhibits the photocorrosion. As a result, the resultant NiFe-Ovac-BVO exhibits good chemical stability and achieves an outstanding photocurrent density of 4.42 ± 0.1 mA·cm-2 at 1.23 V vs reversible hydrogen electrode (RHE), which is 3.7-time higher than that of BVO photoanode. This work supplies an efficient avenue to design photoanode with enhanced photocurrent and stability by using a thin NiFe-MOF layer grafting Ovac-BVO.

Role of Interfacial Defects in Photoelectrochemical Properties of BiVO4 Coated on ZnO Nanodendrites: X-ray Spectroscopic and Microscopic Investigation.

Synchrotron-based X-ray spectroscopic and microscopic techniques are used to identify the origin of enhancement of the photoelectrochemical (PEC) properties of BiVO4 (BVO) that is coated on ZnO nanodendrites (hereafter referred to as BVO/ZnO). The atomic and electronic structures of core-shell BVO/ZnO nanodendrites have been well-characterized, and the heterojunction has been determined to favor the migration of charge carriers under the PEC condition. The variation of charge density between ZnO and BVO in core-shell BVO/ZnO nanodendrites with many unpaired O 2p-derived states at the interface forms interfacial oxygen defects and yields a band gap of approximately 2.6 eV in BVO/ZnO nanocomposites. Atomic structural distortions at the interface of BVO/ZnO nanodendrites, which support the fact that there are many interfacial oxygen defects, affect the O 2p-V 3d hybridization and reduce the crystal field energy 10Dq ∼2.1 eV. Such an interfacial atomic/electronic structure and band gap modulation increase the efficiency of absorption of solar light and electron-hole separation. This study provides evidence that the interfacial oxygen defects act as a trapping center and are critical for the charge transfer, retarding electron-hole recombination, and high absorption of visible light, which can result in favorable PEC properties of a nanostructured core-shell BVO/ZnO heterojunction. Insights into the local atomic and electronic structures of the BVO/ZnO heterojunction support the fabrication of semiconductor heterojunctions with optimal compositions and an optimal interface, which are sought to maximize solar light utilization and the transportation of charge carriers for PEC water splitting and related applications.

Analyses of the brominated vegetable oil in soft drinks using gas chromatography-flame ionization detector and atmospheric pressure gas chromatography-quadrupole/time-of-flight mass spectrometry.

Herein, a new method for quantifying the brominated vegetable oil content in commercial soft drinks was developed, which accelerated the sample preparation process and improved analytical efficiency. First, simple and accurate chromatographic separation techniques were performed using a VF-5ht column for both GC-FID (quantitative) and APGC-QTOF (qualitative) analyses. The samples were subjected to chromatography on a reversed-phase solid-phase extraction cartridge. (PoraPak™RxnRP). Transesterification using a boron trifluoride methanol complex in methanol solution was performed. When validating this method, the analyte recovery percentages were between 82.2% and 99.9%, and the recovery and standard deviation of repeatability values were between 1.2% and 3.5%. Using an isotope library, the bromostearic acid methyl esters (9,10-dibromostearic acid methyl ester, 9,10,12,13-tetrabromostearic acid methyl ester, and hexabromostearic acid methyl ester) in the sample mixtures were qualitatively confirmed via APGC-QTOF. A novel aqueous ammonium adduct, which has not been previously reported, was also confirmed. These results indicated that this new method was simple, accurate, and also allowed for precise qualitative and quantitative confirmation as well as high reproducibility.

Ag-doped BiVO4/BiFeO3 photoanode for highly efficient and stable photocatalytic and photoelectrochemical water splitting.

In a conventional photoelectrochemical (PEC) water splitting system using BiVO4 (BVO), most of the charge carriers have very sluggish photocatalysis reaction kinetics because they are easily recombined from the defects developed from the bulk or the surface of the photoanodes before reaching the fluorine-doped tin dioxide (FTO). Herein, we present a facile design and fabrication technique for a Ag-BVO/BiFeO3 (BFO) heterostructure photoanode by Ag doping and surface passivation with BFO on the as-preparedBVO photoanode. Its photocatalytic properties for PEC water splitting and tetracycline (TC) degradation are compared to those of BVO/BFO, BVO, and Ag-BVO photocatalyst nanoparticle (NP) films. The effect of Ag-doping/BFO surface passivation on the morphological, structural, and optical properties and surface electronic structure of the as-obtainedBVO electrodes was investigated. The photocatalytic degradation of TC in aqueous solution by Ag-BVO/BFO was greatly increased (>1.5-fold) compared to that of BVO. The TC was completely photodegraded in 50 min of visible-light irradiation. The as-preparedAg-BVO/BFO heterojunction photoanode not only exhibited 4-fold higher PEC performance (0.72 mA cm-2 vs. RHE) and stability than those of the pure BVO components, but also the onset potential in the Ag-BVO/BFO photoanode was cathodically shifted by 600 mV compared to that of the bare BVO. The Ag-BVO/BFO photoelectrode with the highest donor density and the lowest charge transfer resistance exhibited a 4.46-fold higher carrier density than that of the pure BVO photoelectrode. More specifically, the Mott-Schottky (MS) and electrochemical impedance spectroscopy (EIS) results demonstrated that the Ag-doping not only effectively increased the carrier charge density of BVO, thus increasing the consumption rate of charge carriers, but also increased the charge transfer and transport efficiencies of the BVO photoanodes.

Identifying method validation and measurement uncertainty of brominated vegetable oil in soft drinks and carbonated waters commonly consumed in South Korea.

This study investigated a method for validating and determining the measurement uncertainty for the composition of brominated vegetable oil (BVO) in soft drinks and carbonated waters commonly consumed in South Korea. First, we studied a simple and precise qualitative colorimetric method at the maximum residues level 15 ppm. And an analytical method using ion chromatography (IC) was validated and identified with brominated fatty acids by gas chromatography electron ionization mass spectrometry (GC/EI-MS). The measurement uncertainty was evaluated based on the precisional study and confirmed by the preliminary inter-laboratory study. For IC analysis, the recovery range of BVO was from 97.8% to 107.2% with relative standard deviations between 0.18% and 0.69%. In addition, the expanded uncertainty of the BVO was 1.59. These results indicate that the validated method is appropriate for identifying of BVO and can be used to verify the safety of soft drinks or carbonated waters containing BVO residues.

The use of bevacizumab and ranibizumab for branch retinal vein occlusion in medicare beneficiaries.

PURPOSE: To describe the frequency and variation of intravitreal bevacizumab and ranibizumab use for branch retinal vein occlusion (BVO) in the United States (US). METHODS: We obtained a 5% random sample of Medicare beneficiaries from the Medicare Denominator and Physician/Supplier Part B claims files from 2010 to 2013 and identified all beneficiaries with an ICD-9-CM code for branch retinal vein occlusion (BVO, 362.36). Patient age, gender, race, state of residence and Charlson Comorbidity Index (CCI) scores were collected. Healthcare Common Procedure Coding System (HSCPS) codes for bevacizumab (J3590, J9035, and J3490) and for ranibizumab (J2778) were used to identify the mode of treatment for each patient. Patients who met the following criteria were excluded from this study: (1) under 65 years of age; (2) residence outside of the 50 United States or the District of Columbia; (3) no Part-B coverage or with HMO coverage that was not processed by Centers for Medicare & Medicaid Services (CMS); (4) concomitant diagnosis of diabetic edema (ICD-9: 362.07) or central retinal vein occlusion (ICD-9: 362.35); and (5) received both or none of the above two treatments. Geographic variation was examined by comparing injection frequencies across the nine US census divisions using Chi-squared analysis. RESULTS: During 2010-2013, a majority of the 3944 BVO patients who met the inclusion criteria received bevacizumab compared to ranibizumab (76.7% vs 23.3%). Most patients were aged 75-79 (22.0%) or 80-84 (22.0%), female (61.5%), white (88.3%), and had a CCI score of 1-2 (39.8%). The frequencies of bevacizumab and ranibizumab injections for BVO varied significantly between the US census divisions (p < 0.0001). The highest frequencies of bevacizumab use were in the Mountain (90.6%) and Pacific (82.7%) divisions while the highest frequencies of ranibizumab use were in the West North Central (37.9%) and Mid Atlantic (32.7%) divisions. CONCLUSIONS AND IMPORTANCE: A majority of Medicare beneficiaries with BVO received bevacizumab compared to ranibizumab from 2010 to 2013, with significant geographic variation in the use of the two anti-VEGF agents. Future research into factors driving geographic variation in the use of these agents may help direct cost-effective strategies for the management of BVO.

Simple and rapid quantification of brominated vegetable oil in commercial soft drinks by LC-MS.

We report here a simple and rapid method for the quantification of brominated vegetable oil (BVO) in soft drinks based upon liquid chromatography-electrospray ionization mass spectrometry. Unlike previously reported methods, this novel method does not require hydrolysis, extraction or derivatization steps, but rather a simple "dilute and shoot" sample preparation. The quantification is conducted by mass spectrometry in selected ion recording mode and a single point standard addition procedure. The method was validated in the range of 5-25µg/mL BVO, encompassing the legal limit of 15µg/mL established by the US FDA for fruit-flavored beverages in the US market. The method was characterized by excellent intra- and inter-assay accuracy (97.3-103.4%) and very low imprecision [0.5-3.6% (RSD)]. The direct nature of the quantification, simplicity, and excellent statistical performance of this methodology constitute clear advantages in relation to previously published methods for the analysis of BVO in soft drinks.