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1.
Biomed Pharmacother ; 173: 116429, 2024 Apr.
Article En | MEDLINE | ID: mdl-38490157

Fibrosis-related diseases (FRD) include conditions like myocardial fibrosis, pulmonary fibrosis, hepatic fibrosis, renal fibrosis, and others. The impact of fibrosis can be severe, causing organ dysfunction, reduced functionality, and even organ failure, leading to significant health issues. Currently, there is a lack of effective modern anti-fibrosis drugs in clinical practice. However, Chinese medicine has a certain beneficial effect on the treatment of such diseases. Angelica sinensis, with its considerable medicinal value, has garnered attention for its anti-fibrosis properties in recent investigations. In the past few years, there has been a growing number of experimental inquiries into the impact of angelica polysaccharide (ASP), angelica water extract, angelica injection, and angelica compound preparation on fibrosis-associated ailments, piquing the interest of researchers. This paper aims to consolidate recent advances in the study of Angelica sinensis for the treatment of fibrosis-related disorders, offering insights for prospective investigations. Literature retrieval included core electronic databases, including Baidu Literature, CNKI, Google-Scholar, PubMed, and Web of Science. The applied search utilized specified keywords to extract relevant information on the pharmacological and phytochemical attributes of plants. The investigation revealed that Angelica sinensis has the potential to impede the advancement of fibrotic diseases by modulating inflammation, oxidative stress, immune responses, and metabolism. ASP, Angelica sinensis extract, Angelica sinensis injection, and Angelica sinensis compound preparation were extensively examined and discussed. These constituents demonstrated significant anti-fibrosis activity. In essence, this review seeks to gain a profound understanding of the role of Angelica sinensis in treating fiber-related diseases. Organ fibrosis manifests in nearly all tissues and organs, posing a critical challenge to global public health due to its widespread occurrence, challenging early diagnosis, and unfavorable prognosis. Despite its prevalence, therapeutic options are limited, and their efficacy is constrained. Over the past few years, numerous studies have explored the protective effects of traditional Chinese medicine on organ fibrosis, with Angelica sinensis standing out as a multifunctional natural remedy. This paper provides a review of organ fibrosis pathogenesis and summarizes the recent two decades' progress in treating fibrosis in various organs such as the liver, lung, kidney, and heart. The review highlights the modulation of relevant signaling pathways through multiple targets and channels by the effective components of Angelica sinensis, whether used as a single medicine or in compound prescriptions.


Angelica sinensis , Pulmonary Fibrosis , Angelica sinensis/chemistry , Prospective Studies , Phytotherapy , Medicine, Chinese Traditional , Pulmonary Fibrosis/drug therapy
2.
Front Pharmacol ; 15: 1343193, 2024.
Article En | MEDLINE | ID: mdl-38313314

Background: Pathological progression from non-alcoholic fatty liver disease (NAFLD) to liver fibrosis (LF) to hepatocellular carcinoma (HCC) is a common dynamic state in many patients. Curcumin, a dietary supplement derived from the turmeric family, is expected to specifically inhibit the development of this progression. However, there is a lack of convincing evidence. Methods: The studies published until June 2023 were searched in PubMed, Web of Science, Embase, and the Cochrane Library databases. The SYstematic Review Center for Laboratory animal Experimentation (SYRCLE) approach was used to evaluate the certainty of evidence. StataSE (version 15.1) and Origin 2021 software programs were used to analyze the critical indicators. Results: Fifty-two studies involving 792 animals were included, and three disease models were reported. Curcumin demonstrates a significant improvement in key indicators across the stages of NAFLD, liver fibrosis, and HCC. We conducted a detailed analysis of common inflammatory markers IL-1ß, IL-6, and TNF-α, which traverse the entire disease process. The research results reveal that curcumin effectively hinders disease progression at each stage by suppressing inflammation. Curcumin exerted hepatoprotective effects in the dose range from 100 to 400 mg/kg and treatment duration from 4 to 10 weeks. The mechanistic analysis reveals that curcumin primarily exerts its hepatoprotective effects by modulating multiple signaling pathways, including TLR4/NF-κB, Keap1/Nrf2, Bax/Bcl-2/Caspase 3, and TGF-ß/Smad3. Conclusion: In summary, curcumin has shown promising therapeutic effects during the overall progression of NAFLD-LF-HCC. It inhibited the pathological progression by synergistic mechanisms related to multiple pathways, including anti-inflammatory, antioxidant, and apoptosis regulation.

3.
Org Lett ; 24(50): 9243-9247, 2022 Dec 23.
Article En | MEDLINE | ID: mdl-36516358

A number of γ-cyanoalkyl radicals were generated by sustainable N-heterocyclic carbene catalysis in tin-, transition-meal-, and light-free conditions, followed by insertion into biaryl isonitriles, thus leading to the rapid assembly of a variety of diversely functionalized 6-cyanoalkyl phenanthridines. A preliminary mechanism study revealed that a single-electron transfer radical process was possibly involved.

4.
Org Lett ; 24(41): 7654-7658, 2022 Oct 21.
Article En | MEDLINE | ID: mdl-36218283

A variety of phenanthridines are rapidly constructed by an N-heterocyclic carbene (NHC)-catalyzed SOMOphilic isocyanide insertion-initiated homolytic aromatic substitution-type radical cyclization in the absence of any light, transition metals, and external oxidants. The aldehyde-free, scalable, and operationally simple protocol tolerates diverse functionalized biaryl isonitriles and activated α-halides. Moreover, it can be further applied to the divergent construction of other N-heterocycles. Preliminary mechanistic studies disclose that an NHC-derived radical cation intermediate is possibly involved.

5.
RSC Adv ; 11(21): 13030-13033, 2021 Mar 29.
Article En | MEDLINE | ID: mdl-35423833

A rhodium-catalyzed, N-H free indole directed cyclization reaction of benzoquinone via a dual C-H activation strategy is disclosed. This protocol has a good functional group tolerance and affords useful indole-fused heterocylces. Besides, it is insensitive to moisture, commercially available solvent can be directly used and work quite well for this transformation.

6.
Future Oncol ; 16(25): 1921-1930, 2020 Sep.
Article En | MEDLINE | ID: mdl-32915667

Aim: To explore FBXW7 protein-coding transcript isoform (α, ß and γ) expression, their functions and prognostic value in ovarian serous cystadenocarcinoma (OSC). Materials & methods: FBXW7 transcript data were collected from The Cancer Genome Atlas and the Genotype-Tissue Expression project. IOSE, A2780 and SKOV3 cells were used for in vitro and in vivo studies. Results: FBXW7α and FBXW7γ are dominant protein-coding transcripts that were downregulated in OSC. FBXW7γ overexpression reduced the protein expression of c-Myc, Notch1 and Yap1 and suppressed OSC cell growth in vitro and in vivo. FBXW7γ expression was an independent indicator of longer disease-specific survival (HR: 0.588; 95% CI: 0.449-0.770) and progression-free survival (HR: 0.708; 95% CI: 0.562-0.892). Conclusion: FBXW7γ is a tumor-suppressive and might be the only prognosis-related FBXW7 transcript in OSC.


Alternative Splicing , Biomarkers, Tumor , Cystadenocarcinoma, Serous/etiology , Cystadenocarcinoma, Serous/mortality , F-Box-WD Repeat-Containing Protein 7/genetics , Gene Expression Regulation, Neoplastic , Ovarian Neoplasms/etiology , Animals , Cell Line, Tumor , Cystadenocarcinoma, Serous/metabolism , Cystadenocarcinoma, Serous/pathology , Disease Models, Animal , Fallopian Tubes/metabolism , Female , Humans , Kaplan-Meier Estimate , Mice , Neoplasm Metastasis , Neoplasm Staging , Ovarian Neoplasms/metabolism , Ovarian Neoplasms/pathology , Prognosis , RNA Isoforms , RNA, Messenger/genetics , Xenograft Model Antitumor Assays
7.
Zhong Yao Cai ; 38(4): 745-50, 2015 Apr.
Article Zh | MEDLINE | ID: mdl-26672339

OBJECTIVE: To study the chemical components from the leaves of Fatsia japonica and their antitumor activities in vitro. METHODS: All compounds were separated and purified by column chromatography over silica gel, Sephadex LH-20 and preparative HPLC. Their structures were identified by physical and chemical properties and spectral methods including 1H-NMR and 13C-NMR. Antitumor assay was measured by MTT method. RESULTS: 18 compounds were isolated and identified as palmitic acid (1), ß-hydroxypropiovanillone (2), adenosine (3), ß-sitosterol (4), daucosterol (5), oleanolic acid (6), echinocystic acid (7), betulinic acid (8), hederagenin(9), hederagenin-3-O-α-L-rhamnopyranosyl(1-->2)-α-L-arabinopyranoside(10), acacetin(11), quercetin(12), quercetin-3-O-ß-D-glucopyranoside(13), isovitexin(14), isovitexin-7-O-glucoside(15), astragalin(16), methylpluviatolide(17), and syringaresinol-4-O-ß-D-glucopyranoside(18). CONCLUSION: All compounds are isolated from the leaves of Fatsia japonica for the first time except compound 1. The ethyl acetate extract and compounds 6, 10, 12 and 18 at the concentration of 0. 5 mg/mL showed inhibitory effect against the proliferation of colon cell line A549 with the inhibitory rate over 90% in vitro.


Antineoplastic Agents, Phytogenic/chemistry , Araliaceae/chemistry , Phytochemicals/chemistry , Plant Leaves/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Cell Line, Tumor , Chromatography, High Pressure Liquid , Flavones , Furans , Glucosides , Humans , Kaempferols , Lactones , Lignans , Oleanolic Acid/analogs & derivatives , Pentacyclic Triterpenes , Phytochemicals/isolation & purification , Sitosterols , Triterpenes , Betulinic Acid
8.
Zhong Yao Cai ; 38(2): 305-10, 2015 Feb.
Article Zh | MEDLINE | ID: mdl-26415406

OBJECTIVE: To study the chemical constituents from the leaves of "Chuju" Chrysanthemum morifolium. METHODS: All compounds were separated and purified by column chromatography over silica gel, Sephadex LH-20 and preparative HPLC. Their structures were identified by spectral methods including 1H-NMR and 13C-NMR. RESULTS: 21 compounds were isolated and identified as octa-cosyl alcohol (1), ß-sitosterol (2), lupeol (3), α-amyrin (4), daucosterol (5), ineupatorolide B (6), syringin (7), chlorogenic acid (8), petasiphenol (9), physcion (10), acacetin (11), eupatilin (12), quercetin (13), diosmetin (14), luteolin (15), apigenin (16), apigenin- 7-O-ß-D-glucopyranoside (17), quercetin-3-O-ß-D-glucopyranoside (18), luteolin-7-O-ß-D-gluco pyranoside (19), apigenin-7-O-ß-D- neospheroside (20), and acacetin-7-O-ß-D-glucoside (21). CONCLUSION: Compounds 1-12, 18 and 20 are isolated from this plant for the first time. Compounds 10, 13, 14, 15 and 16 have shown strong antioxidant activities by DPPH · scavenging activity better than Vit C.


Antioxidants/chemistry , Chrysanthemum/chemistry , Phytochemicals/chemistry , Plant Leaves/chemistry , Plants, Medicinal/chemistry , Apigenin , Chlorogenic Acid , Flavones , Flavonoids , Glucosides , Luteolin , Phenylpropionates , Phytochemicals/isolation & purification , Quercetin , Sitosterols
9.
Zhong Yao Cai ; 38(5): 975-9, 2015 May.
Article Zh | MEDLINE | ID: mdl-26767290

OBJECTIVE: To study the chemical constituents from Hibiscus syriacus leaves and their α-glucosidase inhibitory activities. METHODS: Column chromatography including macroporous resins, silica gel and Sephadex LH-20 were used for the isolation and purification of all compounds. Spectroscopic methods including physical and chemical properties, 1H-NMR and 13C-NMR were used for the identification of structures. Their α-glucosidase inhibitory activities were detected by a 96-well microplate. RESULTS: 15 compounds were isolated and identified as ß-sitosterol(1), ß-daucostero (2), ß-amyrin (3), oleanolic acid (4), stigmast-4-en-3-one (5), friedelin (6), syriacusin A (7), kaempferol (8), isovitexin (9), vitexin (10), apigenin (11), apigenin-7-O-ß-D-glucopyranoside (12), luteolin-7-O-ß-D-glucopyranoside (13), vitexin-7-O-ß-D-glucopyranoside (14) and rutin (15). CONCLUSION: All the compounds are isolated from the leaves of Hibiscus syriacus for the first time. Taking acarbose as positive control, the α-glucosidase inhibitory activities of 15 compounds were evaluated. Compounds 7 and 9 have shown strong α-glucosidase inhibitory activities with IC50 of 39.03 ± 0.38 and 32.12 ± 0.62 mg/L, inhibition ratio of 94.95% and 97.15%, respectively.


Glycoside Hydrolase Inhibitors/chemistry , Hibiscus/chemistry , Phytochemicals/analysis , Plant Leaves/chemistry , Apigenin , Glucosides , Kaempferols , Luteolin , Oleanolic Acid/analogs & derivatives , Sitosterols , Stigmasterol/analogs & derivatives , Triterpenes , alpha-Glucosidases
10.
Mar Drugs ; 12(2): 601-35, 2014 Jan 27.
Article En | MEDLINE | ID: mdl-24473166

Nuclear receptors (NRs) are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors represents an interesting and promising therapeutic approach. The search for novel NR agonists and antagonists with enhanced selectivities prompted the exploration of the extraordinary chemical diversity associated with natural products. Recent studies involving nuclear receptors have disclosed a number of natural products as nuclear receptor ligands, serving to re-emphasize the translational possibilities of natural products in drug discovery. In this review, the natural ligands of nuclear receptors will be described with an emphasis on their mechanisms of action and their therapeutic potentials, as well as on strategies to determine potential marine natural products as nuclear receptor modulators.


Aquatic Organisms/chemistry , Biological Products/pharmacology , Receptors, Cytoplasmic and Nuclear/drug effects , Animals , Biological Products/isolation & purification , Drug Discovery/methods , Humans , Ligands , Molecular Targeted Therapy , Receptors, Cytoplasmic and Nuclear/metabolism , Translational Research, Biomedical/methods
11.
Chemosphere ; 72(4): 532-6, 2008 Jun.
Article En | MEDLINE | ID: mdl-18472131

Degradation of methyl orange under gamma-irradiation was investigated. The reactions followed pseudo first-order kinetics. Apparent degradation rate constant, estimated through linear regression analysis, increased with an increase of dose rate and a decrease of initial methyl orange concentration. Degradation of methyl orange was significantly accelerated under oxidative condition, but was slightly enhanced under reductive condition. However, the result of decoloration was better under reductive condition than oxidative one. An analysis on the intermediates using Fourier transform infrared and gas chromatography/mass spectrometry demonstrates that the radiolytic degradation of methyl orange was processed with different C-N cleavages under oxidative and reductive conditions.


Azo Compounds/chemistry , Azo Compounds/radiation effects , Coloring Agents/chemistry , Gamma Rays , Water/chemistry , Carbon/chemistry , Carbon/isolation & purification , Gas Chromatography-Mass Spectrometry , Kinetics , Oxidation-Reduction/radiation effects , Solutions , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared
12.
Rapid Commun Mass Spectrom ; 22(3): 373-8, 2008.
Article En | MEDLINE | ID: mdl-18183636

High-resolution electrospray ionization multistage tandem mass spectrometry (MS 1-7) in negative ion mode was used to determine the accurate masses and fragmentation pathways of two compounds, 4'-demethylepipodophyllotoxin and 4'-demethyl-4-azido-4-deoxyepipodophyllotoxin, which are key intermediate compounds for the preparation of podophyllotoxin-type anti-cancer drugs. The deprotonated molecules [M-H]* of both compounds were readily observed in the conventional single-stage mass spectra due to the presence of the phenolic hydroxyl group in the molecules. Abundant information on the product ions was obtained from tandem mass spectra (MS 2-7) in negative ion mode. Based on the exact masses acquired from 14 different tandem mass spectra, a similar MSn fragmentation pathway was proposed for both compounds. A characteristic product ion produced in the MS 2-4 product ion scan experiments is the cyclohexylenetrione anion [M-H-2Me-RH]* or [M-H-RH-2Me]* at m/z 351 (C19H11O7) formed by the consecutive losses of two CH3 radicals at the 3'- and 5'-positions and the neutral loss of RH, where R = a 4-substituted group (-OH or -N3), from the [M-H]* ion. This anion may be considered as diagnostic for the presence of this type of compound. The other common cleavages are the neutral losses of CO at least two times in the MS 6,7 product ion spectra. The results of this work could serve as an effective tool for the detection or determination of other derivatives of 4'-demethyl-4beta-substituted podophyllotoxin, which are widely used as intermediates for the preparation of anti-tumor drugs.


Podophyllotoxin/analogs & derivatives , Spectrometry, Mass, Electrospray Ionization/methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Podophyllotoxin/analysis , Podophyllotoxin/chemistry , Reproducibility of Results , Sensitivity and Specificity
13.
Rapid Commun Mass Spectrom ; 21(22): 3613-20, 2007.
Article En | MEDLINE | ID: mdl-17939160

High-resolution electrospray ionization multistage tandem mass spectrometry (MS(1-7)) in positive ion mode was used to determine the accurate masses and the fragmentation pathways of two furofurans, sesamin and gmelinol. The protonated molecules [M+H]+ were absent in the conventional mass spectra of both compounds, but two characteristic ions, [M+H-H(2)O]+ and [M+H-H(2)]+, were always observed. Successive losses of CH(2)O and CO are the common characteristic fragmentations. Based on the exact masses acquired from 21 different tandem mass spectra, two or three fragmentation pathways for each compound are proposed. The consecutive losses of two H(2)O molecules and one H(2) molecule readily take place from the furan rings for both sesamin and gmelinol, resulting in the absence of the protonated molecules in the single-stage experiments. HCHO loss is observed at least three times in the tandem mass spectra, mainly from methylenedioxy groups (OCH(2)O) for sesamin but only from tetrahydrofuran rings for gmelinol. Moreover, CO loss is found at least three times in the tandem mass spectra of both sesamin and gmelinol from the 3,4-methylenedioxyphenyl (ArOCH(2)O) moieties for sesamin and from both the dimethoxyphenyl and the tetrahydrofuran ring moieties for gmelinol. In addition, the disubstituted benzyl cation ArCH(2)+ at m/z 135 for sesamin and at m/z 151 for gmelinol was found in the MS(3) spectra of both sesamin and gmelinol, which is very helpful in the identification of the compositions of 3,4-disubstituted groups on the benzene rings of the furofurans.


Antihypertensive Agents/chemistry , Bridged Bicyclo Compounds/chemistry , Dioxoles/chemistry , Lignans/chemistry , Sesame Oil , Spectrometry, Mass, Electrospray Ionization/methods , Tandem Mass Spectrometry/methods , Antihypertensive Agents/analysis , Bridged Bicyclo Compounds/analysis , Dioxoles/analysis , Lignans/analysis , Molecular Structure , Reproducibility of Results
14.
Rapid Commun Mass Spectrom ; 21(17): 2843-52, 2007.
Article En | MEDLINE | ID: mdl-17661337

High-resolution electrospray ionization multistage tandem mass spectrometry (MS(1-9)) was used to determine the accurate masses and the fragmentation pathways of protonated podophyllotoxin (1) and its corresponding 4'-demethyl-4beta-substituted derivatives (2-4). The protonated molecules, [M + H](+), of all the four compounds were observed in the conventional single-stage mass spectra. Two fragmentation pathways, that appear to be characteristic of the four compounds, are proposed on the basis of their multistage tandem mass spectrometric data. The characteristic elimination, from the precursor protonated ions, of the neutral groups 4-R(1)H, 1-ArH, CO, CH(2)O and C(4)H(4)O(2), in which R is located on C-4, is the common elimination, and the product ions at m/z 267, 239, 229, 181, 173, 153, 143 and 115 are the common diagnostic masses. The elimination of the R(1) group substituent located on the C-4 position of compounds 1-4 has a significant influence on the fragmentation pathway obtained in the conventional single-stage mass spectra. A large R(1) group would be unfavorable for this elimination, unless the collision energy is raised. Apart from the common fragmentations obtained for the protonated molecules 1-4, significant additional product ions were detected in the various multistage tandem mass spectrometric analyses, particularly in the case of the product ions derived initially from the phenolic hydroxyl group of 2-4, which are different from those of 1. Based on these additional formed product ions, several additional fragmentation pathways for 1 or 2-4 are also presented.


Glucosides/analysis , Glucosides/chemistry , Podophyllotoxin/analogs & derivatives , Podophyllotoxin/analysis , Podophyllotoxin/chemistry , Spectrometry, Mass, Electrospray Ionization/methods , Reproducibility of Results , Sensitivity and Specificity
15.
Environ Sci Technol ; 41(6): 1977-82, 2007 Mar 15.
Article En | MEDLINE | ID: mdl-17410793

Steady-state radiolysis experiments were performed to gain insight into the kinetics and mechanisms of nitrobenzene (NB) degradation in aqueous solutions. The degradation of NB under gamma-ray irradiation followed pseudo-first-order kinetics, and the pseudo first-order rate constant and the initial G value of NB decomposition were functionally related to both the initial NB concentration and the irradiation dose rate. Under oxidative conditions, complete mineralization of NB was achieved, whereas no total organic carbon reduction was observed under reductive conditions. The radiolytic products of NB under various conditions were identified using FTIR and GC-MS analyses. The mechanisms behind the radiolytic degradation of NB under both oxidative and reductive conditions were proposed schematically in light of the degradation products observed. In addition, calculations based on ab initio molecular orbital and density functional theory provided support for the proposed mechanisms and the preferred pathways among all the possible reactions.


Gamma Rays , Nitrobenzenes/chemistry , Water Pollution, Chemical/prevention & control , Water/chemistry , Chromatography, High Pressure Liquid , Gas Chromatography-Mass Spectrometry , Kinetics , Molecular Structure , Oxidation-Reduction/radiation effects , Spectroscopy, Fourier Transform Infrared
16.
J Hazard Mater ; 133(1-3): 68-74, 2006 May 20.
Article En | MEDLINE | ID: mdl-16325336

Photodegradation of nitrobenzene (NB) using an excimer UV lamp at a wavelength of 172 nm is investigated. Experimental results show that high concentration nitrobenzene can be efficiently degraded with irradiation by excimer UV lamp, and confirm that degradation of nitrobenzene is more efficient by UV/H(2)O(2) combination than UV only. In the case of using UV only, 60 min of treatment was found to be sufficient to degrade the major part of NB solution with a concentration of less than 4mM. In the case of using the combination of UV/H(2)O(2) with a H(2)O(2) concentration of 7:1 molar ratio to NB, 4.07 mM NB solution drastically decreased to 0.41 mM after treatment for only 20 min. Degradation intermediate products are identified by analyzing the degradation products with GC/HRMS and possible degradation pathways of nitrobenzene are suggested.


Nitrobenzenes/chemistry , Nitrobenzenes/radiation effects , Photolysis/radiation effects , Ultraviolet Rays , Hydrogen Peroxide/chemistry , Ions/chemistry , Mass Spectrometry , Molecular Structure , Solutions , Spectrum Analysis
17.
Chemosphere ; 61(7): 1003-11, 2005 Nov.
Article En | MEDLINE | ID: mdl-15885740

Steady-state radiolysis experiments were performed to investigate the mechanisms of the radiolytic degradation of Acid Orange 7 (AO7) in aqueous solutions, which might be useful for the application of ionizing radiation for the remediation of azo-dye-laden wastewaters. The degradation products formed under various conditions were identified by using UV-Vis, HPLC, FTIR, and GC-MS analyses. With theoretical analysis and degradation products identified, the mechanisms behind the radiolytic degradation of AO7 under both oxidative and reductive conditions were elucidated. Irradiated under reductive conditions AO7 was decomposed through N-N cleavage with the formation of aniline, sodium sulfanilamide, 1-amino-2-naphthol, naphthalidine, 1,2,3,4-tetrahydro-2-naphthol, and 2-naphthol etc., whereas under oxidative conditions both N-N and C-N cleavages might be the initial steps in the radiolytic degradation of AO7.


Azo Compounds/radiation effects , Benzenesulfonates/radiation effects , Coloring Agents/radiation effects , Gamma Rays , Water Pollutants, Chemical/radiation effects , Azo Compounds/chemistry , Benzenesulfonates/chemistry , Chromatography, High Pressure Liquid , Coloring Agents/chemistry , Gas Chromatography-Mass Spectrometry , Oxidation-Reduction , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , Waste Disposal, Fluid , Water Purification/methods
18.
J Hazard Mater ; 119(1-3): 153-8, 2005 Mar 17.
Article En | MEDLINE | ID: mdl-15752860

Effects of an electric or magnetic field on the radiolytic degradation of two biorefractory contaminants, Acid Orange 7 (AO7) and nitrobenzene (NB), were evaluated in this work. A continuous DC electric current with a low density (approximately 2.8-5.6 mA cm(-2)) applied during the radiolytic degradation of AO7 and NB solutions only led to slight enhancement in their degradation rate constants, but altered significantly the degradation mechanisms. On the other hand, application of a magnetic field (0.4 T) in irradiation processes slightly enhanced the degradation kinetics without leading to any change in degradation mechanisms.


Azo Compounds/chemistry , Electromagnetic Fields , Nitrobenzenes/chemistry , Water Purification/methods , Benzenesulfonates , Kinetics , Waste Disposal, Fluid/methods
19.
Rapid Commun Mass Spectrom ; 18(24): 3093-8, 2004.
Article En | MEDLINE | ID: mdl-15562444

Using the accurate masses obtained from a time-of-flight instrument and the tandem mass spectrometric (MS/MS) data from an ion trap instrument, electron ionization mass spectra of a series of 1,4-dihydro-4-substituted 2,6-dimethyl-3,5-bis(alkoxycarbonyl)pyridines are reported and rationalized. Two sets of fragmentation pathways are proposed. One involves the formation of fragment ions containing the 1,4-dihydropyridine structure, and the other of ions containing a pyridine ring.


Pyridines/analysis , Pyridines/chemistry , Molecular Structure , Spectrometry, Mass, Electrospray Ionization
20.
J Environ Sci (China) ; 16(3): 364-6, 2004.
Article En | MEDLINE | ID: mdl-15272703

The degradation of nitrobenzene (NB) by gamma-ray irradiation was studied. The influences of dose rate and initial NB concentration were investigated in details. At a dose rate of 55 Gy/min, the degradation kinetics was pseudo-first-order at NB concentrations from 0.2 mmol/L to 4.0 mmol/L. At an initial NB concentration of 0.8 mmol/L, the degradation of NB at various dose rates also followed pseudo-first-order kinetics. Dissolved oxygen was found to have a positive effect on NB degradation. The degradation products were identified as nitrophenol, nitrosobenzene, and hydroquinone, and so on. Based on the product analysis, possible degradation pathways of nitrobenzene were proposed.


Nitrobenzenes/chemistry , Waste Disposal, Fluid/methods , Water Purification/methods , Gamma Rays , Kinetics
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