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Sample records for benzoyl peroxide

  1. Erythromycin and Benzoyl Peroxide Topical

    Science.gov (United States)

    The combination of erythromycin and benzoyl peroxide is used to treat acne. Erythromycin and benzoyl peroxide are in a class of medications called topical antibiotics. The combination of erythromycin ...

  2. Clindamycin and Benzoyl Peroxide Topical

    Science.gov (United States)

    The combination of clindamycin and benzoyl peroxide is used to treat acne. Clindamycin and benzoyl peroxide are in a class of medications called topical antibiotics. The combination of clindamycin ...

  3. A Three-Step Synthesis of Benzoyl Peroxide

    Science.gov (United States)

    Her, Brenda; Jones, Alexandra; Wollack, James W.

    2014-01-01

    Benzoyl peroxide is used as a bleaching agent for flour and whey processing, a polymerization initiator in the synthesis of plastics, and the active component of acne medication. Because of its simplicity and wide application, benzoyl peroxide is a target molecule of interest. It can be affordably synthesized in three steps from bromobenzene using…

  4. Tetrafluoroethylene telomerization initiated by benzoyl peroxide

    Science.gov (United States)

    Bolshakov, A. I.; Kuzina, S. I.; Kiryukhin, D. P.

    2017-03-01

    The radical telomerization of tetrafluoroethylene initiated by benzoyl peroxide (BP) photolysis at λ ≥ 365 nm is studied in acetone, dichloromethane, carbon tetrachloride, and Freon 114B2 at 25°C. The products of synthesis are a mixture of telomers of different molar masses, segregated into soluble and insoluble fractions. To characterize the radicals initiating telomerization, crystalline BP and its solution in ethanol are subjected to low-temperature (77 K) photolysis, with the liquid system serving as a model for BP behavior in solutions of telogens. It is established that radicals are not only initiators but also participate in chain termination reactions, lowering the telomers' molar mass and thus raising the proportion of the soluble fraction. Telomerization initiated by an initiator compound versus initiation by gamma radiation are compared and discussed.

  5. Allergic Contact Dermatitis to Benzoyl Peroxide Resembling Impetigo.

    Science.gov (United States)

    Kim, Changhyun; Craiglow, Brittany G; Watsky, Kalman L; Antaya, Richard J

    2015-01-01

    A 17-year-old boy presented with recurring severe dermatitis of the face of 5-months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris.

  6. Investigating the Stability of Benzoyl Peroxide in Over-the-Counter Acne Medications

    Science.gov (United States)

    Kittredge, Marina Canepa; Kittredge, Kevin W.; Sokol, Melissa S.; Sarquis, Arlyne M.; Sennet, Laura M.

    2008-01-01

    One of the most commonly used ingredients in over-the-counter acne treatments in cream, gel, and wash form is benzoyl peroxide. It is an anti-bacterial agent that kills the bacterium ("Propionibacterium acne") involved in the formation of acne. The formulation of these products is extremely difficult owing to the instability of benzoyl peroxide.…

  7. Formulation and characterization of benzoyl peroxide gellified emulsions.

    Science.gov (United States)

    Thakur, Naresh Kumar; Bharti, Pratibha; Mahant, Sheefali; Rao, Rekha

    2012-12-01

    The present investigation was carried out with the objective of formulating a gellified emulsion of benzoyl peroxide, an anti-acne agent. The formulations were prepared using four different vegetable oils, viz. almond oil, jojoba oil, sesame oil, and wheat germ oil, owing to their emollient properties. The idea was to overcome the skin irritation and dryness caused by benzoyl peroxide, making the formulation more tolerable. The gellified emulsions were characterized for their homogeneity, rheology, spreadability, drug content, and stability. In vitro permeation studies were performed to check the drug permeation through rat skin. The formulations were evaluated for their antimicrobial activity, as well as their acute skin irritation potential. The results were compared with those obtained for the marketed formulation. Later, the histopathological examination of the skin treated with various formulations was carried out. Formulation F3 was found to have caused a very mild dysplastic change to the epidermis. On the other hand, the marketed formulation led to the greatest dysplastic change. Hence, it was concluded that formulation F3, containing sesame oil (6%w/w), was the optimized formulation. It exhibited the maximum drug release and anti-microbial activity, in addition to the least skin irritation potential.

  8. Photocarcinogenesis and toxicity of benzoyl peroxide in hairless mice after simulated solar radiation

    DEFF Research Database (Denmark)

    Lerche, Catharina M; Philipsen, Peter A; Poulsen, Thomas;

    2010-01-01

    Topical benzoyl peroxide (BPO) gel has long been used to treat acne vulgaris and has recently been combined with clindamycin (BPO-clin). No skin malignancies have been reported after clinical use of BPO, but there has been concern about the possible carcinogenicity of BPO alone and in combination...

  9. Benzoyl peroxide (BPO)-promoted oxidative trifluoromethylation of tertiary amines with trimethyl(trifluoromethyl)silane.

    Science.gov (United States)

    Chu, Lingling; Qing, Feng-Ling

    2010-09-14

    The benzoyl peroxide (BPO)-promoted oxidative functionalization of tertiary amines under transition-metal-free reaction conditions was developed. Various 1-trifluoromethylated tetrahydroisoquinoline derivatives were prepared by employing this method. It constitutes the first example of direct trifluoromethylation of tertiary amines.

  10. Efficacy and safety of topical nadifloxacin and benzoyl peroxide versus clindamycin and benzoyl peroxide in acne vulgaris: A randomized controlled trial

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    S Choudhury

    2011-01-01

    Full Text Available Background : Topical therapy with comedolytics and antibiotics are often advocated for mild and moderate severity acne vulgaris. Nadifloxacin, a new fluoroquinolone with anti-Propionibacterium acnes activity and additional anti-inflammatory activity, is approved for use in acne. This randomized controlled assessor blind trial compared the clinical effectiveness and safety of eight weeks therapy of nadifloxacin 1% versus clindamycin 1% as add-on therapy to benzoyl peroxide (2.5% in mild to moderate grade acne. Materials and Methods : The efficacy parameters were changes in the total, inflammatory and non-inflammatory lesion counts, Investigator Global Assessment (IGA, and Cardiff Acne Disability Index (CADI scales from baseline to study end (eight weeks. All treatment emergent dermatological adverse events were evaluated for safety assessment. Results : Out of 84 randomized subjects (43-nadifloxacin arm and (41-clindamycin 42 in nadifloxacin group, 37 in clindamycin group completed the study. Reduction from baseline of total, inflammatory and non-inflammatory lesion counts were highly significant in both the groups (P<0.0001, but between group differences were not significant. Significant improvement in CADI and IGA scales were noted in both groups. Between-group comparison showed no significant differences. The safety and tolerability profile of both regimens were good and statistically comparable. Conclusions: Topical nadifloxacin, a new fluoroquinolone is effective, tolerable, and safe for mild o moderate facial acne. Its clinical effectiveness is comparable to clindamycin when used as add-on therapy to benzoyl peroxide.

  11. Theoretical Studies on Thermal Decomposition of Benzoyl Peroxide in Ground State

    Institute of Scientific and Technical Information of China (English)

    SUN Cheng-ke; YANG Si-ya; LIN Xue-fei; MA Si-yu; LI Zong-he

    2003-01-01

    Systematic studies of the thermal decomposition mechanism of benzoyl peroxide(BPO) in ground state, leading to various intermediates, products and the potential energy surface(PES) of possible dissociation reactions were made computationally. The structures of the transition states and the activation energies for all the paths causing the formation of the reaction products mentioned above were calculated by the AM1 semi-empirical method. This method is shown to to be one predict correctly the preferred pathway for the title reaction. It has been found that in ground state, the thermal decomposition of benzoyl peroxide has two kinds of paths. The first pathway PhC(O)O-OC(O)Ph→PhC(O)O*→Ph*+CO2 produces finally phenyl radicals and carbon dioxide. And the second pathway PhC(O)OO-C(O)Ph→PhC(O)OO*+PhC(O)*→PhC(O)*+O2→Ph*+CO+O2, via which the reaction takes place only in two steps, produces oxygen and PhC(O)* radicals, and the further thermal dissociation of PhC(O)* is quite difficult because of the high activation energy in ground state. The calculated activation energies and reaction enthalpies are in good agreement with the experimental values. The research results also show that also the thermal dissociation process of the two bonds or the three bonds for the benzoyl peroxide doesn′t take place in ground state.

  12. Analysis of benzoyl-peroxide and formaldehyde as dental allergens by FT-SPR method

    Science.gov (United States)

    Bako, J.; Kelemen, M.; Hegedus, Cs

    2013-12-01

    In parallel with the appearance of new dental materials the number of induced allergic diseases increases. Based on this fact more sensitive detection of allergens is major importance. The Fourier-Transform Surface Plasmon Resonance (FT-SPR) is a sensitive, broadly applicable real-time method for analysing thin layers of materials on gold surfaces. FT-SPR measurement is performed at a fixed angel of incident light, and reflectivity is measured over a range of wavelength in the near infrared. In our study the formaldehyde and benzoyl-peroxide were examined as members of the most common dental allergens by FT-SPR spectroscopy. The aim of this work was the investigation of the suitability of this method for the direct detection of these materials. Different concentrations of formaldehyde and benzoyl-peroxide solutions were measured from this purpose. The individual spectra were measured for all of the solutions, and calibration curves were calculated for the materials for the possibility of the determination of an unknown concentration. In addition, series measurements were performed whereby the association and dissociation properties of formaldehyde or benzoyl-peroxide were described. The results of the experiments proved that the method capable to measure directly these materials and can provide appropriate calibration curves for determination of unknown concentrations.

  13. Photocarcinogenesis and toxicity of benzoyl peroxide in hairless mice after simulated solar radiation

    DEFF Research Database (Denmark)

    Lerche, Catharina M; Philipsen, Peter A; Poulsen, Thomas;

    2010-01-01

    Topical benzoyl peroxide (BPO) gel has long been used to treat acne vulgaris and has recently been combined with clindamycin (BPO-clin). No skin malignancies have been reported after clinical use of BPO, but there has been concern about the possible carcinogenicity of BPO alone and in combination...... with UV radiation. BPO can promote skin tumorigenesis in a mouse skin chemical carcinogenesis model. As acne vulgaris is frequently localized on sun-exposed areas, we investigated whether BPO or BPO-clin accelerates photocarcinogenesis in combination with simulated solar radiation (SSR) in 12 groups of 25...

  14. Comparative evaluation of retinoic acid, benzoyl peroxide and erythromycin lotion in acne vulgarils

    Directory of Open Access Journals (Sweden)

    Dogra A

    1993-01-01

    Full Text Available Ninety three patients suffering from acne vulgaris were treated with 0.05% retinoic acid (23 patients, 10% benzyoyl peroxide (24 patients, 2% erythromycin lotin (25 patients and 50% glycerine in methylated spirit (21 patients used as a control, for a period of 6 weeks. The patients were evaluated at 2 weeks and 6 weeks by spot counting of the lesions and diagrammatic representations. Good to excellent results were obtained in 69.6% of patients of erythromycin lotion. Retinoic acid was more effective in reducing noninflammatory lesions (75.2% whereas inflammatory lesions showed better response (73.6% with erythromycin lotion and benzoyl peroxide was almost equally effective in both types of lesions.

  15. Comparison of a chlorhexidine and a benzoyl peroxide shampoo as sole treatment in canine superficial pyoderma.

    Science.gov (United States)

    Loeffler, A; Cobb, M A; Bond, R

    2011-09-01

    The clinical and antibacterial efficacy of two shampoos used as a sole antibacterial treatment in dogs with superficial pyoderma were investigated and compared. In a randomised, partially blinded study, a 3 per cent chlorhexidine gluconate shampoo (Chlorhex 3; Leo Animal Health) was compared against a 2.5 per cent benzoyl peroxide shampoo (Paxcutol; Virbac) in 22 dogs with superficial pyoderma. Dogs were washed two to three times weekly with a 10-minute contact time over 21 days. Clinical scores and bacterial counts were assessed on days 1, 8 and 22 and compared within and between treatment groups; overall response was assessed at the end of the study. Twenty dogs completed the study; 15 (68.2 per cent) showed an overall clinical improvement and the clinical signs resolved in three chlorhexidine-treated dogs. In the chlorhexidine-treated group, scores for papules/pustules (P<0.001), investigator-assessed pruritus (P=0.003), total bacterial counts (P=0.003) and counts for coagulase-positive staphylococci (P=0.003) were reduced after three weeks. Scores and bacterial counts did not vary significantly in the benzoyl peroxide-treated group.

  16. Effect on serum sex hormone levels, immune index of benzoyl peroxide combining with Hirudoid on acne vulgaris

    Institute of Scientific and Technical Information of China (English)

    Lin Li; Jie Sun; The authorsi-heng Yu; Yun-hao Hu

    2015-01-01

    Objective:To observe the effect on serum sex hormone levels, immune index of benzoyl peroxide combining with Hirudoid on acne vulgaris.Methods: 185 patients with acne vulgaris included in the study the authorsre divided into the observation group (85 cases) and the control group (80 cases), the observation group was given the treatment of benzoyl peroxide combining with Hirudoid, and the control group was treated with benzoyl peroxide. To observe the change of hormones (T, FSH, LH, E2) and immune indexes (IgG, IgA, IgM, C3, C4, IL-2, sIL-2R) after 1 month of treatment.Results: After treatment, IgG, C3, C4, IL-2 of the observation group the authorsre significantly different than those before trteatment(P0.05); After treatment, IgG, C3, C4, IL-2 level of two groups the authorsre statistically significant (P<0.05).Where the authorsre no significant difference on sex hormones betthe authorsen the two groups before and after treatment.Conclusion:Benzoyl peroxide combining with Hirudoid has certain effects on immune function for the patients with acne vulgaris, and may be related to therapeutic effect, but no obvious effect on sex hormone.

  17. The Influence of Benzoyl Peroxide on Gelation Rate of Silica Binder for Precision Casting

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    M. Nadolski

    2013-04-01

    Full Text Available Substituting of ethyl silicate with ecologic sols of colloidal silica in the investment casting technology, resulting from the increased demands concerning environmental protection, caused the prolongation of production cycle for precision castings produced in multi-layer thin-walled ceramic shell moulds. Modification of Sizol 030 binder with benzoyl peroxide, proposed in the paper, was aimed at restriction of time needed for realization of a single layer of the shell mould, and by the same, of such a mould as a whole. Examination of kinetics of the drying process were held for the layers made of prepared moulding material and the influence of binder modification on the mould curing time was determined.

  18. DFT MODELING OF BENZOYL PEROXIDE ADSORPTION ON α-Cr2O3 (0001) SURFACE

    Science.gov (United States)

    Maldonado, Frank; Stashans, Arvids

    2016-04-01

    Density functional theory (DFT) within the generalized gradient approximation (GGA) has been used to investigate possible adsorption configurations of benzoyl peroxide (BPO) molecule on the chromium oxide (α-Cr2O3) (0001) surface. Two configurations are found to lead to the molecular adsorption with corresponding adsorption energies being equal to -0.16 and -0.48eV, respectively. Our work describes in detail atomic displacements for both crystalline surface and adsorbate as well as discusses electronic and magnetic properties of the system. The most favorable adsorption case is found when the chemical bond between one of the molecular oxygens and one of the surface Cr atoms has been formed.

  19. The effect of dietary lipid on skin tumor promotion by benzoyl peroxide: comparison of fish, coconut and corn oil.

    Science.gov (United States)

    Locniskar, M; Belury, M A; Cumberland, A G; Patrick, K E; Fischer, S M

    1991-06-01

    Fish or vegetable oils were fed during the promotion stage of a mouse skin carcinogenesis model in order to investigate the effects of dietary fat on tumor development. Two weeks after initiation with 10 nmol dimethylbenz[a]anthracene, SENCAR mice were divided into five groups and maintained on one of the following semipurified diets containing 10% total fat and varying the type of fat: 8.5% coconut oil (CT)/1.5% corn oil (CO); 1% menhaden oil (MO)/7.5% CT/1.5% CO; 4% MO/4.5% CT/1.5% CO; 8.5% MO/1.5% CO; or 10% CO. Promotion with twice-weekly applications of 40 mg benzoyl peroxide was begun 2 weeks later and continued for 52 weeks. No statistically significant differences in kcal food consumed or body weights were observed between diet groups. Papilloma latency, incidence and yield differed among the diet groups with the group fed the 8.5% CT/1.5% CO diet having the shortest latency and highest papilloma incidence and number. In addition, carcinoma latency and incidence was assessed and the first carcinoma appeared in the group fed 8.5% CT/1.5% CO after 20 weeks of benzoyl peroxide treatment; this group yielded the highest carcinoma incidence throughout the study. In comparison, the group fed the 10% CO diet had the longest latency period, and among the lowest papilloma and carcinoma incidence and fewest tumors. In parallel studies, ornithine decarboxylase activity, vascular permeability and hyperplasia were elevated in the epidermis of benzoyl peroxide-treated mice but the extent of the response did not correlate with the different rates of tumor formation observed among the diet groups. These data indicate that dietary fat modulates tumor promotion by benzoyl peroxide in this skin carcinogenesis model with the predominantly saturated fat diet producing the highest rates of papilloma and carcinogen formation and the polyunsaturated fat diet the lowest.

  20. Development and in-vitro characterization of fish oil oleogels containing benzoyl peroxide and salicylic acid as keratolytic agents.

    Science.gov (United States)

    Rehman, K; Tan, C M; Zulfakar, M H

    2014-03-01

    Topical keratolytic agents such as benzoyl peroxide (BP) and salicylic acid (SA) are one of the common treatments for inflammatory skin diseases. However, the amount of drug delivery through the skin is limited due to the stratum corneum. The purposes of this study were to investigate the ability of fish oil to act as penetration enhancer for topical keratolytic agents and to determine the suitable gelator for formulating stable fish oil oleogels. 2 types of gelling agents, beeswax and sorbitan monostearate (Span 60), were used to formulate oleogels. To investigate the efficacy of fish oil oleogel permeation, commercial hydrogels of benzoyl peroxide (BP) and salicylic acid (SA) were used as control, and comparative analysis was performed using Franz diffusion cell. Stability of oleogels was determined by physical assessments at 20°C and 40°C storage. Benzoyl peroxide (BP) fish oil oleogels containing beeswax were considered as better formulations in terms of drug permeation and cumulative drug release. All the results were found to be statistically significant (pskin and stability.

  1. Multicenter study to evaluate efficacy and irritation potential of benzoyl peroxide 4% cream in hydrophase base (Brevoxyl in acne vulgaris

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    Sawleshwarkar S

    2003-01-01

    Full Text Available In this multicenter, open, non-comparative study, the efficacy and irritation potential of 4% benzoyl peroxide cream in hydrophase base (Brevoxyl was evaluated for the treatment of acne vulgaris. All evaluable patients (n=567 received treatment with 4% benzoyl peroxide cream in hydrophase base for six weeks. The investigators evaluated the patients at baseline and at 1,2,4 & 6 weeks. Patients also rated their improvement and adverse effects. Doctor′s assessment showed that at the end of 6′h week 85.6% had good to very good effect of the treatment. The profile of side effects observed by doctors revealed that 53.8% of total patients did not have any irritation whereas only 11.6% had moderate to severe irritation. 53.8% of patients did not report any irritation: 41.4% had some irritation whereas only 4.8% patients reported troublesome irritation. A satisfactory response was reported as ear;y as two weeks and most of the patients had a very satisfactory response after six weeks and were willing to continue the treatment. This supports the theory that the hydrophase formulation in ′Brevoxyl helped to enhance efficacy and decrease the irritation associated with use of benzoyl peroxide.

  2. Polymeric micellar nanocarriers of benzoyl peroxide as potential follicular targeting approach for acne treatment.

    Science.gov (United States)

    Kahraman, Emine; Özhan, Gül; Özsoy, Yıldız; Güngör, Sevgi

    2016-10-01

    The aim of this work was to optimize polymeric nano-sized micellar carriers of the anti-acne compound benzoyl peroxide (BPO) and to examine the ability of these carriers to deposit into hair follicles with the objective of improving skin delivery of BPO. BPO loaded polymeric micelles composed of Pluronic(®) F127 were prepared by the thin film hydration method and characterized in terms of size, loading capacity, morphology and physical stability. The optimized micelle formulation was then selected for skin delivery studies. The penetration of BPO loaded micellar carriers into skin and skin appendages across full thickness porcine skin was examined in vitro. Confocal microscopy images confirmed the penetration of Nile Red into hair follicles, which was loaded into micellar carriers as a model fluorescent compound. The relative safety of the polymeric micelles was evaluated with the MTT viability test using mouse embryonic fibroblasts. The results indicated that nano-sized polymeric micelles of BPO composed of Pluronic(®) F127 offer a potential approach to enhance skin delivery of BPO and that targeting of micelles into hair follicles may be an effective and safe acne treatment.

  3. Bioavailability of Clindamycin From a New Clindamycin Phosphate 1.2%-Benzoyl Peroxide 3% Combination Gel.

    Science.gov (United States)

    Jones, Terry M; Jasper, Stacy; Alió Sáenz, Alessandra B

    2013-01-01

    A new topical fixed-dose combination product containing clindamycin (1%, formulated as 1.2% clindamycin phosphate, CLNP 1.2%) with low strength (3%) benzoyl peroxide (BPO) in a methylparaben-free gel vehicle (CLNP 1.2%-BPO 3%-MPF) has been developed for the treatment of acne. The objective of this study was to determine the relative bioavailability of clindamycin and clindamycin sulfoxide from CLNP 1.2%-BPO 3%-MPF compared with clindamycin phosphate 1.2%-BPO 5% in a methylparaben-preserved gel vehicle (CLNP 1.2%-BPO 5%-MP) and clindamycin phosphate 1.2%-BPO 5% in a methylparaben-free gel vehicle (CLNP 1.2%-BPO 5%-MPF), and to determine whether exposure is affected by BPO concentration (3% vs. 5%) when applied topically. Seventy-two subjects with moderate-severe acne were randomized to receive CLNP 1.2%-BPO 3%-MPF, CLNP 1.2%-BPO 5%-MP, or CLNP 1.2%-BPO 5%-MPF in a 5-day, open-label, and parallel-group study. Cmax and AUC values for clindamycin were highest for CLNP 1.2%-BPO 5%-MP, followed by CLNP 1.2%-BPO 3%-MPF and CLNP 1.2%-BPO 5%-MPF, but differences were not statistically significant. Systemic exposure to clindamycin and clindamycin sulfoxide was low and comparable between the formulations. Results indicate that differences in BPO concentration do not influence clindamycin bioavailability.

  4. [Detection of benzoyl peroxide in wheat flour by NIR diffuse reflectance spectroscopy technique].

    Science.gov (United States)

    Zhang, Zhi-yong; Li, Gang; Liu, Hai-xue; Lin, Ling; Zhang, Bao-ju; Wu, Xiao-rong

    2011-12-01

    Adding benzoyl peroxide (BPO) into wheat flour was prohibited by the relevant government departments since May 1, 2011. And it is of great importance to detect BPO additive amount in wheat flour quickly and accurately. Part of BPO which was added into wheat flour will be deoxidized into benzoic acid, and this make it complex to detect the original BPO additive amount. The objective of the present research is to investigate the potential of NIR diffuse reflectance spectroscopy as a way for measurement of BPO original adding amount in wheat flour. A total of 133 wheat flour samples were prepared by adding different content of BPO into pure wheat flour. Spectra data were obtained by NIR spectrometer and then denoised by wavelet transform. Ninety seven samples were taken as calibration set and other 36 samples as prediction set. Partial least squares regression (PLSR) was applied to establish the calibration model between BPO original adding contents and the spectra data. The determination coefficient of model for the calibration set is 0.8901, and root mean squared error of calibration (RMSEC) is 40.85 mg x kg(-1). The determination coefficient for the prediction set is 0.8865, and root mean squared error of prediction (RMSEP) is 44.69 mg x kg(-1). The result indicates that it is feasible to detect the BPO adding contents in wheat flour by NIR diffuse reflectance spectroscopy technique and this technique has the potential to measure some other additives in food.

  5. A rapid and sensitive spectrophotometric method for the determination of benzoyl peroxide in wheat flour samples

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    Kraingkrai Ponhong

    2015-12-01

    Full Text Available A simple, rapid, and sensitive spectrophotometric method for the determination of benzoyl peroxide (BPO in wheat flour samples was developed. The detection principle is based on BPO reacted with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS to obtain a blue-green colored product that was detected at 415 nm by spectrophotometry. The effect of factors influencing the color reaction was investigated. Under the selected conditions, the linear range for quantification of BPO was observed between 0.2–1.0 mg L−1 with r2 = 0.998. The limit of detection (LOD was 0.025 mg L−1. The developed method obtained superior precision (relative standard deviation < 2% using 11 repeatability at 0.2 mg L−1, 0.6 mg L−1, and 0.8 mg L−1. The proposed methodology was successfully applied to determine BPO in wheat flour samples.

  6. Efficacy of the addition of salicylic acid to clindamycin and benzoyl peroxide combination for acne vulgaris.

    Science.gov (United States)

    Akarsu, Sevgi; Fetil, Emel; Yücel, Filiz; Gül, Eylem; Güneş, Ali T

    2012-05-01

    Clindamycin phosphate (CDP), benzoyl peroxide (BPO) and salicylic acid (SA) are known to be effective acne therapy agents depending on their anti-inflammatory and comedolytic properties. The purpose of this study was to investigate the efficacy and tolerability of the addition of SA treatment to CDP and BPO (SA and CDP + BPO) and compare it with CDP + BPO in patients with mild to moderate facial acne vulgaris. Forty-nine patients were enrolled in a 12 week prospective, single-blind, randomized, comparative clinical study. Efficacy was assessed by lesion counts, global improvement, quality of life index and measurements of skin barrier functions. Local side effects were also evaluated. Both combinations were effective in reducing total lesion (TL), inflammatory lesion (IL) and non-inflammatory lesion (NIL) counts. There were statistically significant differences between treatment groups for reductions in NIL counts beyond 2 weeks, IL counts and TL counts throughout the all study weeks, and global improvement scores evaluated by patients and investigator at the end of the study in favor of SA and CDP + BPO treatment when compared to CDP + BPO treatment. Both combinations significantly decreased stratum corneum hydration, although skin sebum values decreased with SA and CDP + BPO treatment. These combinations were also well tolerated except significantly higher frequency of mild to moderate transient dryness in patients applied SA and CDP + BPO. The addition of SA to CDP + BPO treatment demonstrated significantly better and faster results in terms of reductions in acne lesion counts and well tolerated except for higher frequency of mild to moderate transient dryness.

  7. Comparison of the efficacy and safety of topical clindamycin and 5% benzoyl peroxide with nadifloxacin cream and 5% benzoyl peroxide gel in the treatment of acne vulgaris and assessment of the effects of these treatments on quality of life

    Directory of Open Access Journals (Sweden)

    Aslıhan Kırkağaç

    2015-03-01

    Full Text Available Background and Design: Acne vulgaris is a multifactorial chronic inflammatory disase of the pilosebaceous unit. Topical antibiotics and anti-inflammatory treatment are used for mild and moderate acne. Clindamycin is frequently used for acne treatment, altough nadifloxacin is a relatively new agent. There are few studies evaluating nadifloxacin efficacy. It's impact on quality of life has not been determined previously. In this study, it is aimed to compare the effect of these two agents, and to evaluate the effect of these treatments on quality of life. Materials and Methods: Eighty patients with mild-moderate acne vulgaris were divided in two groups of 40 people that had no difference in terms of age, gender and acne severity. The combination of topical clindamycin and 5% benzoyl peroxide gel twice a day was given to group 1 for 12 weeks. The combination of nadifloxacin cream and 5% benzoyl peroxide gel twice a day was given to group 2 for 12 weeks. The number of the inflammatory and non-inflammatory lesions were recorded at baseline and on weeks 2, 4, 8, 12 and side effects were recorded and evaluated. Global improvement was evaluated separately by patients and doctor after the treatment. Before and after the treatment, the quality of life of the patients were evaluated with Skindex-29. Results: Both treatment group regimens were significantly effective on inflammatory and non-inflammatory lesions and were well tolerated by patients in terms of side effects. It was also observed that there was statistically significant recovery after treatment in terms of clinical severity and quality of life. There was not any statistically significant difference between two treatment methods in terms of effectiveness, side effect and quality of life. Conclusion: Nadifloxacin and 5% benzoyl peroxide combination is effective in the treatment and improvement of quality of life in acne patients.

  8. Effect of temperature and concentration on benzoyl peroxide bleaching efficacy and benzoic acid levels in whey protein concentrate.

    Science.gov (United States)

    Smith, T J; Gerard, P D; Drake, M A

    2015-11-01

    Much of the fluid whey produced in the United States is a by-product of Cheddar cheese manufacture and must be bleached. Benzoyl peroxide (BP) is currently 1 of only 2 legal chemical bleaching agents for fluid whey in the United States, but benzoic acid is an unavoidable by-product of BP bleaching. Benzoyl peroxide is typically a powder, but new liquid BP dispersions are available. A greater understanding of the bleaching characteristics of BP is necessary. The objective of the study was to compare norbixin destruction, residual benzoic acid, and flavor differences between liquid whey and 80% whey protein concentrates (WPC80) bleached at different temperatures with 2 different benzoyl peroxides (soluble and insoluble). Two experiments were conducted in this study. For experiment 1, 3 factors (temperature, bleach type, bleach concentration) were evaluated for norbixin destruction using a response surface model-central composite design in liquid whey. For experiment 2, norbixin concentration, residual benzoic acid, and flavor differences were explored in WPC80 from whey bleached by the 2 commercially available BP (soluble and insoluble) at 5 mg/kg. In liquid whey, soluble BP bleached more norbixin than insoluble BP, especially at lower concentrations (5 and 10 mg/kg) at both cold (4°C) and hot (50°C) temperatures. The WPC80 from liquid whey bleached with BP at 50°C had lower norbixin concentration, benzoic acid levels, cardboard flavor, and aldehyde levels than WPC80 from liquid whey bleached with BP at 4°C. Regardless of temperature, soluble BP destroyed more norbixin at lower concentrations than insoluble BP. The WPC80 from soluble-BP-bleached wheys had lower cardboard flavor and lower aldehyde levels than WPC80 from insoluble-BP-bleached whey. This study suggests that new, soluble (liquid) BP can be used at lower concentrations than insoluble BP to achieve equivalent bleaching and that less residual benzoic acid remains in WPC80 powder from liquid whey

  9. Simple and fast fluorescence detection of benzoyl peroxide in wheat flour by N-methoxy rhodamine-6G spirolactam based on consecutive chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wei; Shi Wen; Li Zhao [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Ma Huimin, E-mail: mahm@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liu Yang; Zhang Jinghua; Liu Qingjun [Beijing Center for Physical and Chemical Analysis, Beijing 100089 (China)

    2011-12-05

    Graphical abstract: A simple and fast method for fluorescence detection of benzoyl peroxide in wheat flour by N-methoxy rhodamine-6G spirolactam (1) is proposed based on consecutive chemical reactions. Highlights: Black-Right-Pointing-Pointer Benzoyl peroxide can oxidize Fe{sup 2+} into Fe{sup 3+}. Black-Right-Pointing-Pointer Fe{sup 3+} selectively induces the opening of rhodamine spirolactam ring. Black-Right-Pointing-Pointer The two reactions led to the development of a new fluorescent method for benzoyl peroxide. Black-Right-Pointing-Pointer The method is simple and fast, and is used to detect benzoyl peroxide in wheat flour. - Abstract: Benzoyl peroxide (BPO) as a brightener is often added to wheat flour, and excessive use of this food additive is receiving increasing concern. Herein, a simple and fast method for fluorescence detection of BPO is proposed based on consecutive chemical reactions. In this approach, BPO first oxidizes Fe{sup 2+} into Fe{sup 3+} and the resulting Fe{sup 3+} then induces the opening of the spirolactam ring of a new rhodamine derivative, N-methoxy rhodamine-6G spirolactam, switching on fluorescence of the detection system. More importantly, the fluorescence response of the reaction system to BPO is rather rapid and sensitive, with a detection limit of 6 mg kg{sup -1} (k = 3), which makes it to be of great potential use in food safety analysis. The applicability of the proposed method has been successfully demonstrated on the determination of BPO in wheat flour samples.

  10. Do tutorials on application method enhance adapalene-benzoyl peroxide combination gel tolerability in the treatment of acne?

    Science.gov (United States)

    Kwon, Hyuck Hoon; Park, Seon Yong; Yoon, Ji Young; Min, Seonguk; Suh, Dae Hun

    2015-11-01

    Fixed-dose combination adapalene 0.1% and benzoyl peroxide 2.5% gel (A-BPO) has rarely been studied for Asian acne patients, while they have complained of local irritations more often when applying individual components. In this study, we compared A-BPO gel with benzoyl peroxide (BPO) in terms of efficacy and tolerability in Korean patients first, and assessed the clinical benefit of a dermatological tutorial on application technique in reducing irritations for A-BPO. This study was conducted as a single-blind controlled split-face trial for a 12-week period. Each half facial side of 85 patients was randomly assigned to either A-BPO or BPO. Success rate, lesion counts and safety profiles were evaluated (analysis I). During initial assignment, all patients were further randomized to either dermatological tutorial (DT) or non-tutorial (NT) subgroups depending on the presence of dermatologists' tutorials for application methods to their A-BPO sides. Clinical data of the A-BPO side was compared between two subgroups (analysis II). As a result, A-BPO gel outperformed BPO, demonstrating better efficacy in success rates and lesion counts as early as 1 week. However, A-BPO proved significantly less tolerable compared with both BPO and previous A-BPO data from Caucasians. Bioengineering measurements further confirmed clinical data (analysis I). The DT subgroup achieved much better tolerability with comparable therapeutic efficacies compared with the NT subgroup (analysis II). In conclusion, A-BPO demonstrated higher efficacies in acne compared with BPO in Korean patients, while skin irritation levels were notable concurrently. Dermatologists' education for application methods would significantly decrease these side-effects, maintaining superior efficacy levels.

  11. COMPARATIVE STUDY OF CLINICAL EFFICACY AND SIDE EFFECTS OF ADAPALENE 0.1% GEL AND BENZOYL PEROXIDE 2.5% GEL AS MONOTHERAPIES AND COMBINATION THERAPY IN FACIAL ACNE: INDIAN PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Adarsh

    2014-04-01

    Full Text Available A fixed dose combination gel with adapalene 0.1% and benzoyl peroxide 2.5% has been developed for the once daily treatment of acne vulgaris .This fixed combination was approved by U.S FDA in December 2008. This study was done in the Department of Dermatology, KIMS, Bangalore to assess the efficacy and adverse effects of topical adapalene 0.1%–benzoyl peroxide 2.5% combination gel as compared to topical adapalene 0.1% gel and 2.5% benzoyl peroxide gel (monotherapies in the treatment of facial acne vulgaris. To the best of our knowledge, this is one of the few studies conducted in India. It was an open label study. Participants received either adapalene 0.1% gel, benzoyl peroxide 2.5% gel or adapalene 0.1% – benzoyl peroxide 2.5% combination gel for 12 weeks. Follow up was done at the end of 1,2,4,8 and 12 weeks. Evaluation included lesion count and adverse events. Participants included males and females aged between 18-38 years with grade 2 or 3 facial acne vulgaris as per investigators global assessment of acne scale. A total of 62 participants were recruited out of which 23 were males and 39 were females.88.71% participants completed the study. The study revealed that combination of adapalene 0.1% and benzoyl peroxide 2.5% gel was more effective in the treatment of facial acne as compared to adapalene 0.1% gel and benzoyl peroxide 2.5% gel (topical monotherapies. The safety of combination of adapalene 0.1% and benzoyl peroxide 2.5% gel was comparable with adapalene 0.1% gel and benzoyl peroxide 2.5% gel monotherapies.

  12. A New, Once-daily, Optimized, Fixed Combination of Clindamycin Phosphate 1.2% and Low-concentration Benzoyl Peroxide 2.5% Gel for the Treatment of Moderate-to-Severe Acne

    OpenAIRE

    Gold, Michael H.

    2009-01-01

    The treatment of acne with combination therapy is commonplace with treatment aimed at sustained efficacy with minimal side effects, maximum adherence, and the avoidance of bacterial resistance. Combinations containing clindamycin and benzoyl peroxide have been shown to be effective, but the irritation caused by the concentration of benzoyl peroxide 5% in the more commonly used, fixed combinations can be limiting. In addition, surfactants, preservatives, and high levels of organic solvents, in...

  13. In situ Preparation of Tri-Fe(Ⅲ) and Bi-Cu(Ⅱ) Clusters from Benzoyl Peroxide Reacting with Metal Powders

    Institute of Scientific and Technical Information of China (English)

    YANG Jun-wei; ZHANG Jing; TONG Shan-ling; HUANG Xiao-chun; YAN Yan

    2009-01-01

    Three crystal architectures, including one organic compound of benzoyl peroxide(l) and two clusters of tri-iron(Ⅲ) and bi-cupper(Ⅱ) with benzoic ligands(2 and 3), were self-assembled by an in situ redox way of benzoyl peroxide oxidants reacting with Mo, Fe and Cu powders, respectively. X-ray crystallographic results show that both the asymmetry tri-iron(Ⅲ) cluster and the benzoylperoxide crystal architecture (2 and 1) with complicated 3D networks were constructed by intermolecular hydrogen-bonding interactions. Contrarily, the symmetrical bi-copper(Ⅱ) cluster crystal architecture(3), only with π-π stacking between paralleled phenyl groups and without any intermolecular hydrogen-bonding interactions, only presented an 1D zigzag chain along the a-axis.

  14. Benzoyl Peroxide Formulated Polycarbophil/Carbopol 934P Hydrogel with Selective Antimicrobial Activity, Potentially Beneficial for Treatment and Prevention of Bacterial Vaginosis

    OpenAIRE

    Shiqi Xu; Cavera, Veronica L.; Rogers, Michael A.; Qingrong Huang; Konstantin Zubovskiy; Chikindas, Michael L.

    2013-01-01

    The human vagina is colonized by a variety of indigenous microflora; in healthy individuals the predominant bacterial genus is Lactobacillus while those with bacterial vaginosis (BV) carry a variety of anaerobic representatives of the phylum Actinobacteria. In this study, we evaluated the antimicrobial activity of benzoyl peroxide (BPO) encapsulated in a hydrogel against Gardnerella vaginalis, one of the causative agents of BV, as well as indicating its safety for healthy human lactobacilli. ...

  15. Dependence of Adhesion Property of Epoxidized Natural Rubber (ENR 25/Ethylene-Propylene-Diene Rubber Blend Adhesives Crosslinked by Benzoyl Peroxide

    Directory of Open Access Journals (Sweden)

    B. T. Poh

    2014-01-01

    Full Text Available The loop tack, peel strength, and shear strength of crosslinked epoxidized natural rubber (ENR 25/ethylene-propylene-diene rubber (EPDM blend adhesives were investigated. Coumarone-indene resin, toluene, and benzoyl peroxide were used as the tackifier, solvent, and crosslinking agent, respectively, throughout the experiment. The adhesive was coated on a polyethylene terephthalate (PET substrate using a SHEEN hand coater at 60 μm and 120 μm coating thickness. It was cured at 80°C for 30 minutes before testing on a Lloyd adhesion tester operating at testing rates from 10 to 60 cm min−1. Results show that loop tack and peel strength of the ENR 25/EPDM adhesive pass through a maximum value at 2 parts per hundred parts of rubber (phr of benzoyl peroxide content. This observation is attributed to the increase in crosslinking which enhances the cohesive strength of the adhesive. Further addition of the crosslinking agent decreases the tack and peel strength due to the decrease in wettability of the over-crosslinked adhesive. Shear strength, however, increases steadily with benzoyl peroxide content, an observation which is associated with the steady increase in the cohesive strength. The adhesion properties increase with increasing coating thickness and testing rate.

  16. In vitro antimicrobial activity of benzoyl peroxide against Propionibacterium acnes assessed by a novel susceptibility testing method.

    Science.gov (United States)

    Okamoto, Kazuaki; Ikeda, Fumiaki; Kanayama, Shoji; Nakajima, Akiko; Matsumoto, Tatsumi; Ishii, Ritsuko; Umehara, Masatoshi; Gotoh, Naomasa; Hayashi, Naoki; Iyoda, Takako; Matsuzaki, Kaoru; Matsumoto, Satoru; Kawashima, Makoto

    2016-06-01

    Benzoyl peroxide (BPO), a therapeutic agent for acne vulgaris, was assessed for in vitro antimicrobial activity against Propionibacterium acnes using a novel broth microdilution testing that improved BPO solubility. We searched for a suitable culture medium to measure the minimum inhibitory concentration (MIC) of BPO against P. acnes and finally found the Gifu anaerobic medium (GAM) broth supplemented with 0.1(v/v)% glycerol and 2(v/v)% Tween 80, in which BPO dissolved up to 1250 μg/mL and P. acnes grew well. The MICs and minimum bactericidal concentrations (MBCs) of BPO against 44 clinical isolates of P. acnes collected from Japanese patients with acne vulgaris were determined by our testing method using the supplemented GAM broth. The MICs of BPO were 128 or 256 μg/mL against all isolates of P. acnes regardless of susceptibility to nadifloxacin or clindamycin. The MBCs of BPO were also 128 or 256 μg/mL against the same isolates. Moreover, BPO at the MIC showed a rapid bactericidal activity against P. acnes ATCC11827 in time-kill assay. In conclusion, we could develop a novel assay for the MIC and MBC determinations of BPO against P. acnes, which is reliable and reproducible as a broth microdilution testing and the present results suggest that BPO has a potent bactericidal activity against P. acnes.

  17. The efficacy, safety and tolerability of adapalene versus benzoyl peroxide in the treatment of mild acne vulgaris; a randomized trial.

    Science.gov (United States)

    Babaeinejad, S H; Fouladi, R F

    2013-09-01

    Topical treatments, such as adapalene and benzoyl peroxide (BPO), are popular in mild-to-moderate acne vulgaris. This study aimed to compare the efficacy, safety and tolerability of adapalene and BPO in mild acne vulgaris. In this single-center, randomized, double-blind, clinical trial, 60 patients with mild acne vulgaris received either topical adapalene 0.1% gel or topical BPO 2.5% gel on their face once daily for two months. The changes of acne lesion count (efficacy), any adverse effect (safety), and the patients' overall satisfaction (tolerability) were compared after 3 months of follow-up. In both groups the mean number of noninflammatory, inflammatory and total lesions decreased significantly from baseline (10.77±5.54, 9.73±5.09, and 20.50±7.54, respectively in adapalene group; 11.50±5.92, 8.43±5.45, and 19.93±9.01, respectively in BPO group) to the third month (1.70±1.68, 0.33±0.66, and 0.50±0.78, respectively in adapalene group; 4.23±4.14, 0.33±0.71, and 4.13±4.44, respectively in BPO group; Pacne vulgaris, with a marginal tendency toward the former.

  18. The efficacy, safety, and tolerability of adapalene versus benzoyl peroxide in the treatment of mild acne vulgaris: a randomized trial.

    Science.gov (United States)

    Babaeinejad, S H; Fouladi, R F

    2013-07-01

    Topical treatments, such as adapalene and benzoyl peroxide (BPO), are popular in mild-to-moderate acne vulgaris. This study aimed to compare the efficacy, safety and tolerability of adapalene and BPO in mild acne vulgaris. In this single-center, randomized, double-blind, clinical trial, 60 patients with mild acne vulgaris received either topical adapalene 0.1% gel or topical BPO 2.5% gel on their face once daily for two months. The changes of acne lesion count (efficacy), any adverse effect (safety), and the patients' overall satisfaction (tolerability) were compared after 3 months of follow-up. In both groups the mean number of noninflammatory, inflammatory and total lesions decreased significantly from baseline (10.77±5.54, 9.73±5.09, and 20.50±7.54, respectively in adapalene group; 11.50±5.92, 8.43±5.45, and 19.93±9.01, respectively in BPO group) to the third month (1.70±1.68, 0.33±0.66, and 0.50±0.78, respectively in adapalene group; 4.23±4.14, 0.33±0.71, and 4.13±4.44, respectively in BPO group; Pacne vulgaris, with a marginal tendency toward the former.

  19. Dependence of Adhesion Property of Epoxidized Natural Rubber (ENR 25)/Ethylene-Propylene-Diene Rubber Blend Adhesives Crosslinked by Benzoyl Peroxide

    OpenAIRE

    B. T. Poh; Y. Y. Teh

    2014-01-01

    The loop tack, peel strength, and shear strength of crosslinked epoxidized natural rubber (ENR 25)/ethylene-propylene-diene rubber (EPDM) blend adhesives were investigated. Coumarone-indene resin, toluene, and benzoyl peroxide were used as the tackifier, solvent, and crosslinking agent, respectively, throughout the experiment. The adhesive was coated on a polyethylene terephthalate (PET) substrate using a SHEEN hand coater at 60 μm and 120 μm coating thickness. It was cured at 80°C for 30 min...

  20. Formulation and evaluation of a topical niosomal gel containing a combination of benzoyl peroxide and tretinoin for antiacne activity.

    Science.gov (United States)

    Gupta, Ankush; Singh, Sima; Kotla, Niranjan G; Webster, Thomas J

    2015-01-01

    A skin disease, like acne, is very common and normally happens to everyone at least once in their lifetime. The structure of the stratum corneum is often compared with a brick wall, with corneocytes surrounded by the mortar of the intercellular lipid lamellae. One of the best options for successful drug delivery to the affected area of skin is the use of elastic vesicles (niosomes) which can be transported through the skin through channel-like structures. In this study, a combination of tretinoin (keratolytic agent) and benzoyl peroxide (BPO) (a potent antibacterial) was given by using niosomes as promising carriers for the effective treatment of acne by acting on a pathogenic site. In this section, niosomal gel formulation encapsulated drugs have been evaluated for in vitro, ex vivo, and in vivo, for their predetermined characteristics; and finally the stability of the niosome gel was tested at different temperature conditions for understanding of the storage conditions required for maintaining the quality of formulation attributes. The prepared niosome was found to be in the range of 531 nm with a zeta potential of -43 mV; the entrapment efficiencies of tretinoin (TRA) and BPO niosomes were found to be 96.25%±0.56% and 98.75%±1.25%, respectively. The permeated amount of TRA and BPO from the niosomal gel after 24 hours was calculated as 6.25±0.14 μg/cm(2) and 5.04±0.014 μg/cm(2), respectively. A comparative drug retention study in Wistar rat skin using cream, an alcoholic solution, and a niosomal gel showed 11.54 μg, 2.68 μg, and 15.54 μg amounts of TRA and 68.85 μg, 59.98 μg, and 143.78 μg amounts of BPO were retained in the layers of skin, respectively. In vivo studies of the niosomal gel and antiacne cream of TRA and BPO showed that the niosomal gel was more efficacious than the antiacne cream because niosomal gels with a 4.16-fold lower dose of BPO provided the same therapeutic index at targeted sites in comparison to the antiacne cream.

  1. Determination of Benzoyl Peroxide Content in Wheat Flour Based on Spectrophotometry%分光光度法测定小麦面粉中过氧化苯甲酰含量

    Institute of Scientific and Technical Information of China (English)

    张建夫; 任凯; 赵小萍

    2011-01-01

    [目的]用分光光度法测定面粉及面制品中过氧化笨甲酰含量.[方法]在磷酸介质中,过氧化苯甲酰氧化碘化钾生成的碘与淀粉显色,在520 nm波长处有最大吸收峰,建立了淀粉碘化钾体系光度法间接测定微量过氧化苯甲酰的方法.[结果]面粉用无水乙醇溶解通过离心提取过氧化苯甲酰,过氧化苯甲酰的质量浓度在0.032 g/L以内呈线性.[结论]该方法应用于新制小麦面粉中过氧化苯甲酰的测定,回收率在94.3%以上,步骤简单,易操作,现象明显.%[ Objective ]The aim was to determine benzoyl peroxide content in wheat flour and flour products based on spectrophotometry. [ Method] In phosphoric acid medium,potassium iodide oxidized by benzoyl peroxide oxidation,then generated colored iodine and starch,there was maximum absorption peak in 585 nm wavelength,thereby,the starch potassium iodide system spectrophotometry was established to determine benzoyl peroxide. [ Result ] Flour dissolved by ethanol extraction through centrifugal benzoyl peroxid, benzoyl peroxide concentration in the 0.032 g/L or less linearly. [Conclusion]The new method has been applied to wheat flour produced in the determination of benzoyl peroxide,and the recovery is 94.3% and above. The experimental results show that the steps of the method is simple and easy to operate,the phenomenon is obvious.

  2. Investigation of the formation of benzoyl peroxide, benzoic anhydride, and other potential aerosol products from gas-phase reactions of benzoylperoxy radicals

    Science.gov (United States)

    Strollo, Christen M.; Ziemann, Paul J.

    2016-04-01

    The secondary organic aerosol (SOA) products of the reaction of benzaldehyde with Cl atoms and with OH radicals in air in the absence of NOx were investigated in an environmental chamber in order to better understand the possible role of organic peroxy radical self-reactions in SOA formation. SOA products and authentic standards were analyzed using mass spectrometry and liquid chromatography, and results show that the yields of benzoyl peroxide (C6H5C(O)OO(O)CC6H5) and benzoic anhydride (C6H5C(O)O(O)CC6H5), two potential products from the gas-phase self-reaction of benzoylperoxy radicals (C6H5C(O)OO·), were less than 0.1%. This is in contrast to results of recent studies that have shown that the gas-phase self-reactions of β-nitrooxyperoxy radicals formed from reactions of isoprene with NO3 radicals form dialkyl peroxides that contribute significantly to gas-phase and SOA products. Such reactions have also been proposed to explain the gas-phase formation of extremely low volatility dimers from autooxidation of terpenes. The results obtained here indicate that, at least for benzoylperoxy radicals, the self-reactions form only benzoyloxy radicals. Analyses of SOA composition and volatility were inconclusive, but it appears that the SOA may consist primarily of oligomers formed through heterogeneous/multiphase reactions possibly involving some combination of phenol, benzaldehyde, benzoic acid, and peroxybenzoic acid.

  3. Recent advances in the use of adapalene 0.1%/benzoyl peroxide 2.5% to treat patients with moderate to severe acne.

    Science.gov (United States)

    Leyden, James

    2016-01-01

    The central role of inflammation in acne is now more clearly understood. Adapalene, a third-generation topical retinoid, down-regulates toll-like receptor 2 expression and inhibits activator protein-1 activity. In a fixed-dose combination, adapalene and benzoyl peroxide (BPO) act synergistically on inflammatory patterns through regulation of innate immunity. In addition to reducing inflammatory and non-inflammatory lesions, adapalene/BPO helps prevent lesion and microcomedone formation. The combination of a topical retinoid and antimicrobial agent remains the preferred approach for almost all patients with acne. In cases of more severe disease, there is a clinical benefit in combining adapalene/BPO with an oral antibiotic for 12 weeks. Most recently, adapalene/BPO plus doxycycline 200 mg was found to be highly effective when compared with isotretinoin in the treatment of patients with severe acne with nodules. Long-term maintenance therapy is needed for most patients. Retinoids are the preferred agents, with BPO added in patients with more severe disease if needed. Adapalene is anticomedogenic, reduces comedones and has anti-inflammatory properties, while BPO is a unique antimicrobial agent not shown to induce microbial resistance after more than 50 years of use. Maintenance therapy for 6 months with adapalene/BPO prevents relapse among patients with severe acne and continues to reduce disease symptoms.

  4. Benzoyl peroxide formulated polycarbophil/carbopol 934P hydrogel with selective antimicrobial activity, potentially beneficial for treatment and prevention of bacterial vaginosis.

    Science.gov (United States)

    Xu, Shiqi; Cavera, Veronica L; Rogers, Michael A; Huang, Qingrong; Zubovskiy, Konstantin; Chikindas, Michael L

    2013-01-01

    The human vagina is colonized by a variety of indigenous microflora; in healthy individuals the predominant bacterial genus is Lactobacillus while those with bacterial vaginosis (BV) carry a variety of anaerobic representatives of the phylum Actinobacteria. In this study, we evaluated the antimicrobial activity of benzoyl peroxide (BPO) encapsulated in a hydrogel against Gardnerella vaginalis, one of the causative agents of BV, as well as indicating its safety for healthy human lactobacilli. Herein, it is shown that in well diffusion assays G. vaginalis is inhibited at 0.01% hydrogel-encapsulated BPO and that the tested Lactobacillus spp. can tolerate concentrations of BPO up to 2.5%. In direct contact assays (cells grown in a liquid culture containing hydrogel with 1% BPO or BPO particles), we demonstrated that hydrogels loaded with 1% BPO caused 6-log reduction of G. vaginalis. Conversely, three of the tested Lactobacillus spp. were not inhibited while L. acidophilus growth was slightly delayed. The rheological properties of the hydrogel formulation were probed using oscillation frequency sweep, oscillation shear stress sweep, and shear rate sweep. This shows the gel to be suitable for vaginal application and that the encapsulation of BPO did not alter rheological properties.

  5. The effect of benzoyl peroxide 9.8% emollient foam on reduction of Propionibacterium acnes on the back using a short contact therapy approach.

    Science.gov (United States)

    Leyden, James J; Del Rosso, James Q

    2012-07-01

    Benzoyl peroxide (BP) exerts its therapeutic effect for acne vulgaris through reduction of Propionibacterium acnes. A 1.0 to 2.0 log reduction in P acnes has been demonstrated primarily on the face with use of "leave-on" BP formulations, but also with some BP cleansers. In addition to use for facial acne vulgaris, cleanser formulations of BP are commonly used for truncal acne vulgaris due to ease of use on a large body-surface area and to avoid bleaching of fabric. To date, evaluation of P acnes reduction on the trunk has not been well studied with BP formulations, especially with the use of recognized and standardized methods to accurately determine P acnes colony counts. A previous study demonstrated that a BP 8% cleanser did not reduce counts of P acnes on the back when subjects were instructed to apply the cleanser in the shower, allow it to dry for 20 seconds on the skin, and then rinse off the cleanser. Evaluation of specified time intervals between application on the back and rinsing with BP formulations would help to better define the necessary skin contact time associated with high reductions of P acnes (>90%), recognizing also the potential roles of BP concentration and vehicle. This 2 week study using quantitative bacteriologic cultures evaluates the effectiveness of BP 9.8% emollient foam in reducing P acnes levels on the back with 2 minutes of skin contact time and compares results with a BP 5.3% "leave-on" emollient foam formulation. Short contact therapy utilizing a 2 minute skin contact time with BP 9.8% emollient foam used once daily over a 2 week duration was highly effective in reducing the quantity of P acnes organisms on the back and provided comparable colony count reduction to "leave on" therapy using BP 5.3% emollient foam.

  6. Comparison of clindamycin 1% and benzoyl peroxide 5% gel to a novel composition containing salicylic acid, capryloyl salicylic acid, HEPES, glycolic acid, citric acid, and dioic acid in the treatment of acne vulgaris.

    Science.gov (United States)

    Baumann, Leslie S; Oresajo, Christian; Yatskayer, Margarita; Dahl, Amanda; Figueras, Kristian

    2013-03-01

    This study evaluated the tolerance and efficacy of 2 facial skin products in subjects with acne using the following acne treatments: 1) treatment A, a combination of salicylic acid, capryloyl salicylic acid, HEPES, glycolic acid, citric acid, and dioic acid, and 2) treatment B (BenzaClin®, clindamycin 1% and benzoyl peroxide 5% gel). The treatment design included the split-face application of treatment A and treatment B and the full-face application of the cleanser, moisturizer, and sunscreen. Data were collected through physician visual assessments, subject irritation questionnaires and assessments, along with clinical photography. Results showed similar tolerance and efficacy for both treatments.

  7. Efficacy of combined therapy of oral minocycline and benzoyl peroxide for acne%口服米诺环素联合过氧化苯甲酰治疗痤疮疗效观察

    Institute of Scientific and Technical Information of China (English)

    梁新亮; 张守民

    2011-01-01

    目的 探讨米诺环素联合外用过氧化苯甲酰治疗痤疮的疗效性,分析两者联合用药与单独口服米诺环素在治疗痤疮疗效方面的差异性,从而为痤疮临床治疗提供较好的方案.方法 将45名患者随机分为治疗组和对照组,治疗组接受米诺环素联合过氧化苯甲酰治疗,对照组接受米诺环素治疗,对治疗组和对照组不同疗程(用药后2、4、6、8周及1个月)治愈率的比较,作出评价.结果 治疗2周、4周后,米诺环素联合过氧化苯甲酰组总有效率明显高于单口服米诺环素组(P<0.05),6周、8周及1个月时两组无明显差异(P>0.05),说明米诺环素联合过氧化苯甲酰组起效快于单口服米诺环素组.结论 米诺环素联合过氧化苯甲酰较单独口服米诺环素起效快,明显缩短病程,较快减轻炎症反应,降低愈后遗留瘢痕的可能性.%Objective To explore the curative effect of combined therapy of oral minocycline and benzoyl peroxide for external use for acne, and to analyze the difference in the efficacy of acne treatment between the combined therapy and single oral minocycline treatment group, all these will provide us a better scheme for acne treatment. Methods Totally 45 patients were randomly divided into treatment and contrast groups. The treatment group accepted the therapy of minocycline combined with benzoyl peroxide, while the contrast group were treated with minocycline alone. Then an evaluation was made by comparing the curative ratio at different time point between the two groups. Results The total effective rate of the group treated with minocycline combined with benzoyl peroxide was significantly higher than that of single oral minocycline group at 2 weeks and 4 weeks after treatment, while the values at different time of 6 weeks,8 weeks and 1 month after treatment had no significant difference between two groups. It showed that treatment with oral minocycline and benzoyl peroxide for external use

  8. 超临界水中添加过氧化苯甲酰对聚丙烯降解的促进作用%An Investigation on Polypropylene Degradation in Supercritical Water Adding Benzoyl Peroxide

    Institute of Scientific and Technical Information of China (English)

    苏磊; 吴学华; 刘秀茹; 陈丽英; 陈克宇; 洪时明

    2005-01-01

    The effect of benzoyl peroxide (BPO) on polypropylene (PP) degradation in supercritical water was investigated with the aim of developing a process for recycling of waste plastics. A series of experiments with and without BPO were carried out at temperatures of 653K and 673K under pressure about 26 MPa for 30, 75 and 120 min respectively. Products were analyzed by an Ostward-type viscometer, gas chromatography and spectrometry (GC/MS) etc. The results indicated that mean molecular weight of the samples decreased greatly along with the time elapsing or with the temperature increasing, and PP was decomposed to aliphatic and cycloparaffinic hydrocarbons but a few benzenoid hydrocarbons. By comparing the experiments with and without BPO, it was made clear that BPO is an effective additive on PP degradation in supercritical water.

  9. Is benzoyl peroxide 3% topical gel effective and safe in the treatment of acne vulgaris in Japanese patients? A multicenter, randomized, double-blind, vehicle-controlled, parallel-group study.

    Science.gov (United States)

    Kawashima, Makoto; Hashimoto, Hirofumi; Alio Sáenz, Alessandra B; Ono, Makoto; Yamada, Masahiro

    2014-09-01

    Benzoyl peroxide (BPO) as an anti-acne medication is not yet approved in Japan. This study evaluated the efficacy and safety of a once-daily topical application of BPO 3% gel versus an inert vehicle gel in Japanese acne patients. Three hundred and sixty patients were randomized to receive BPO 3% or vehicle for 12 weeks. The primary efficacy end-point was absolute change in number of total lesions (TL) from baseline to week 12 to demonstrate the superiority of BPO 3% versus vehicle. Secondary efficacy end-points were absolute and percent change in TL, inflammatory lesions (IL), non-inflammatory lesions (non-IL) and Investigator's Static Global Assessment (ISGA). Change in TL counts from baseline to week 12 for BPO 3% was superior to vehicle (difference, -21.0; P BPO 3% at all study visits. The proportion of patients with improvement in ISGA scores was significantly higher with BPO 3% than with vehicle from week 2. All adverse events were mild or moderate. Adverse drug-related reactions were higher for BPO 3% (30%) than with vehicle (5%). Local tolerability scores of grade 1 or more (slight to moderate) were more frequent with BPO 3% than vehicle with the most significant differences observed in dryness (56% vs 27% at week 1-4), peeling (19% vs 9% at week 1-2) and burning/stinging (58% vs 15% at week 1-12). These results indicate that BPO 3% is effective while maintaining a favorable safety and tolerability profile in Japanese acne patients.

  10. A cross-sectional pilot study of antibiotic resistance in Propionibacterium acnes strains in Indian acne patients using 16s-RNA polymerase chain reaction: A comparison among treatment modalities including antibiotics, benzoyl peroxide, and isotretinoin

    Directory of Open Access Journals (Sweden)

    Kabir Sardana

    2016-01-01

    Full Text Available Background: Antibiotic resistance is a worldwide problem in acne patients due to regional prescription practices, patient compliance, and genomic variability in Propionibacterium acnes, though the effect of treatment on the resistance has not been comprehensively analyzed. Aims: Our primary objective was to assess the level of antibiotic resistance in the Indian patients and to assess whether there was a difference in the resistance across common treatment groups. Subjects and Methods: A cross-sectional, institutional based study was undertaken and three groups of patients were analyzed, treatment naοve, those on antibiotics and patients on benzoyl peroxide (BPO and/isotretinoin. The follicular content was sampled and the culture was verified with 16S rRNA polymerase chain reaction, genomic sequencing, and pulsed-field gel electrophoresis. Minimum inhibitory concentration (MIC assessment was done for erythromycin (ERY, azithromycin (AZI, clindamycin (CL, tetracycline (TET, doxycycline (DOX, minocycline (MINO, and levofloxacin (LEVO. The four groups of patients were compared for any difference in the resistant strains. Results: Of the 52 P. acnes strains isolated (80 patients, high resistance was observed to AZI (100%, ERY (98%, CL (90.4%, DOX (44.2%, and TETs (30.8%. Low resistance was observed to MINO (1.9% and LEVO (9.6%. Statistical difference was seen in the resistance between CL and TETs; DOX/LEVO and DOX/MINO (P < 0.001. High MIC90 (≥256 μg/ml was seen with CL, macrolides, and TETs; moreover, low MIC90 was observed to DOX (16 μg/ml, MINO (8 μg/ml, and LEVO (4 μg/ml. Though the treatment group with isotretinoin/BPO had the least number of resistant strains there was no statistical difference in the antibiotic resistance among the various groups of patients. Conclusions: High resistance was seen among the P. acnes strains to macrolides-lincosamides (AZI and CL while MINO and LEVO resistance was low.

  11. Cross-sectional Pilot Study of Antibiotic Resistance in Propionibacterium Acnes Strains in Indian Acne Patients Using 16S-RNA Polymerase Chain Reaction: A Comparison Among Treatment Modalities Including Antibiotics, Benzoyl Peroxide, and Isotretinoin

    Science.gov (United States)

    Sardana, Kabir; Gupta, Tanvi; Kumar, Bipul; Gautam, Hemant K; Garg, Vijay K

    2016-01-01

    Background: Antibiotic resistance is a worldwide problem in acne patients due to regional prescription practices, patient compliance, and genomic variability in Propionibacterium acnes, though the effect of treatment on the resistance has not been comprehensively analyzed. Aims: Our primary objective was to assess the level of antibiotic resistance in the Indian patients and to assess whether there was a difference in the resistance across common treatment groups. Subjects and Methods: A cross-sectional, institutional based study was undertaken and three groups of patients were analyzed, treatment naïve, those on antibiotics and patients on benzoyl peroxide (BPO) and/isotretinoin. The follicular content was sampled and the culture was verified with 16S rRNA polymerase chain reaction, genomic sequencing, and pulsed-field gel electrophoresis. Minimum inhibitory concentration (MIC) assessment was done for erythromycin (ERY), azithromycin (AZI), clindamycin (CL), tetracycline (TET), doxycycline (DOX), minocycline (MINO), and levofloxacin (LEVO). The four groups of patients were compared for any difference in the resistant strains. Results: Of the 52 P. acnes strains isolated (80 patients), high resistance was observed to AZI (100%), ERY (98%), CL (90.4%), DOX (44.2%), and TETs (30.8%). Low resistance was observed to MINO (1.9%) and LEVO (9.6%). Statistical difference was seen in the resistance between CL and TETs; DOX/LEVO and DOX/MINO (P < 0.001). High MIC90 (≥256 μg/ml) was seen with CL, macrolides, and TETs; moreover, low MIC90 was observed to DOX (16 μg/ml), MINO (8 μg/ml), and LEVO (4 μg/ml). Though the treatment group with isotretinoin/BPO had the least number of resistant strains there was no statistical difference in the antibiotic resistance among the various groups of patients. Conclusions: High resistance was seen among the P. acnes strains to macrolides-lincosamides (AZI and CL) while MINO and LEVO resistance was low. PMID:26955094

  12. 21 CFR 184.1157 - Benzoyl peroxide.

    Science.gov (United States)

    2010-04-01

    ...; milk used for production of Asiago fresh and Asiago soft cheese (§ 133.102), Asiago medium cheese... chapter; and annatto-colored whey, such that the final bleached product conforms to the descriptions and specifications for whey, concentrated whey, or dried whey in § 184.1979(a) (1), (2), or (3), respectively....

  13. Inner-shell excitation spectroscopy of peroxides

    NARCIS (Netherlands)

    Harding, K. L.; Kalirai, S.; Hayes, R.; Ju, V.; Cooper, G.; Hitchcock, A. P.; Thompson, M. R.

    2015-01-01

    O 1s inner-shell excitation spectra of a number of vapor phase molecules containing peroxide bonds - hydrogen peroxide (H2O2), di-t-butylperoxide ((BuOBu)-Bu-t-Bu-t), benzoyl peroxide, ((C6H5(CO)O)(2)), luperox-F [1,3(4)-bis(tertbutylperoxyisopropyl)benzene], and analogous, non-peroxide compounds -

  14. A facile BPO-mediated ortho-hydroxylation and benzoylation of N-alkyl anilines for synthesis of 2-benzamidophenols.

    Science.gov (United States)

    Zhang, Zhi-Jing; Quan, Xue-Jing; Ren, Zhi-Hui; Wang, Yao-Yu; Guan, Zheng-Hui

    2014-06-20

    A facile benzoyl peroxide (BPO) mediated ortho-hydroxylation and benzoylation of N-alkyl anilines for the synthesis of 2-benzamidophenols has been developed. The reaction tolerates a wide range of functional groups and is a good method for the straightforward synthesis of valuable 2-benzamidophenols in good yields under mild conditions.

  15. Estudo clínico, prospectivo, aberto, randomizado e comparativo para avaliar a segurança e a eficácia da luz azul versus peróxido de benzoíla 5% no tratamento da acne inflamatória graus II e III A prospective, randomized, open and comparative study to evaluate the safety and efficacy of blue light treatment versus a topical benzoyl peroxide 5% formulation in patients with acne grade II and III

    Directory of Open Access Journals (Sweden)

    Lúcia H. F. de Arruda

    2009-10-01

    Full Text Available FUNDAMENTOS: Muitos pacientes relatam melhora da acne com a exposição à luz solar, e vários estudos demonstram que a luz azul é efetiva no tratamento da acne. OBJETIVOS: Verificar a segurança e a eficácia da luz azul (espectro eletromagnético de 407 a 420 nm no tratamento da acne inflamatória graus II e III, comparada à terapêutica tópica com peróxido de benzoíla a 5%. MÉTODOS: O estudo avaliou 60 pacientes em cinco visitas: uma de seleção, uma com 7, 14 e 28 dias de tratamento e uma última de seguimento, 14 dias após o término do tratamento. Trinta foram randomizados para luz azul (oito sessões, duas vezes por semana, e outros 30, para peróxido de benzoíla a 5%, duas vezes ao dia, diariamente. A avaliação foi por meio da contagem das lesões e fotografias. RESULTADOS: A redução no número médio de lesões foi semelhante com os dois tratamentos, independente do tipo de lesão (p 0,05, porém o tratamento com a luz azul apresentou menos efeitos colaterais. CONCLUSÕES: A luz azul foi um tratamento tão eficaz quanto o peróxido de benzoíla a 5% para o tratamento da acne graus II e III, mas com menos efeitos adversos.BACKGROUND: Many acne patients improve after exposure to sunlight and there are many reports about the efficacy of blue light phototherapy on acne lesions. OBJECTIVES - The purpose of this study was to evaluate efficacy and safety of blue light treatment versus topical benzoyl peroxide 5% formulation in patients with acne grades II and III. METHODS - Sixty volunteers with facial acne were included and evaluated in 5 visits: the first one for screening, another 3 held on days 7, 14 and 28 of treatment, and the last one after 14 days of the end of treatment. Thirty of them were irradiated with Blue Light (8 times, twice a week and the other thirty were treated with topical Benzoyl Peroxide 5% formulation, auto-applied twice a day, every day. We assessed the severity of acne by counting the lesions and

  16. A Novel Benzoyl Peroxide Biosensor Based on the Synergistic Effects of Gold Nanorods and Horseradish Peroxidase Composite Membrane%基于金纳米棒-辣根过氧化物酶协同效应的过氧化苯甲酞生物传感器

    Institute of Scientific and Technical Information of China (English)

    曾云龙; 李霞飞; 黄昊文; 唐春然; 赵环; 胡娅梅; 李进

    2011-01-01

    将金纳米棒(AuNRs)和辣根过氧化物酶(HRP)以自组装的方式依次修饰到Au电极表面,构建了响应过氧化苯甲酸(BPO)生物传感器.采用循环伏安法和电流时间法研究了传感器的电化学性质和最佳工作条件;由于HRP/AuNRs复合膜的协同效应,电极性能得到显著改善.在最佳工作条件下(工作电压-0.02 V,pH 7的磷酸盐缓冲体系),BPO浓度在5.0×10-6-1.0×10-4mol/L范围内与电极的电流响应值呈良好的线性关系,线性回归方程为:i(μA) =12.6796C(mmol/L) + 0.2406,R= 0.9993.电极的检出限为8.5×10-7mol/L.电极用于面粉中BPO的测定,平行测定6次,平均回收率为97.9%-100.1%,相对标准偏差(RSD)为0.5%-2.1%.本方法用于商品面粉中的BPO测定,取得满意结果.%A novel benzoyl peroxide (BPO) biosensor was prepared by self-assembling of gold nano-rods (AuNRs) and horseradish peroxidase (HRP) on the surface of gold electrode by layer-by-layer. The electrocatalytic behavior and the optimum conditions of the biosensor were investigated by cyclic voltammetry and I-t curves in PBS. Taking the advantages of synergistic effect between AuNRs and HRP, the performance of the biosensor has been improved remarkably. Under the optimum condi-tions, -0. 02 V and PBS pH 7, the current response of the biosensor was linearly proportional to BPO concentration ranged from 5.0× 10-6 mol/L to 1.0×10-4 mol/L with a correlation coefficient of 0. 9993 for benzoyl peroxide determination, and a detection limit of 8. 5×10-7 mol/L. The linear regression equation was I(μA) = 12. 6796C(mmol/L)+0. 2406. The recovery of the BPO in flour and the RSD were 97. 9% - 100. 1% and 0. 5% - 2. 1% with 6 times determinations, respectively. The method was applied to the determination of BPO in flour in the market with satisfactory results.

  17. Benzoyl peroxide-induced damage to DNA and its components

    DEFF Research Database (Denmark)

    Hazlewood, C; Davies, Michael Jonathan

    1996-01-01

    , sugars, nucleosides, nucleotides, RNA, and DNA have been examined and the intermediate species have been identified in many cases. Comparison of these data with those obtained with Ph. alone has allowed the reactions of PhCO2. and Ph. to be distinguished. Evidence has been obtained which is consistent...... with both the addition of these radicals to the C5-C6 double bond of the pyrimidines to give adduct species, and hydrogen abstraction from the sugar rings. The former process is the major reaction for nucleosides and nucleotides. Studies with RNA and DNA also provide strong evidence for the formation...

  18. Photocarcinogenesis promotion studies with benzoyl peroxide (BPO) and croton oil.

    Science.gov (United States)

    Epstein, J H

    1988-08-01

    Previous studies demonstrated that BPO can promote chemically initiated tumor formation in SENCAR mice. In addition, a number of chemicals have been shown to promote and/or enhance UVR induced carcinogenesis. This study examined the effect of BPO on UVR initiated tumor formation. One hundred and forty-eight Uscd mice received 270 mJ/cm2 of UVB radiation to the posterior halves of their backs 3 times a week for 8 weeks. Four weeks later the mice were divided into 4 groups. Group I received croton oil in acetone applications to the back 5 times a week for the duration of the study. Group II received acetone, Group III received the BPO diluent, and Group IV received the BPO in an aqueous diluent applications as in Group I. One mouse in Group II (acetone) and one in Group IV (BPO) developed tumors in unirradiated skin. In the UVR initiated skin 38% of the survivors developed tumors in Group I (croton oil), whereas 5% did in Group II (acetone), 8% in Group III (BPO base), and 8% group IV (BPO). Thus under the circumstances of this study croton oil did promote UV initiated tumor formation but BPO did not. These results are consistent with those recently reported by Iversen.

  19. Singlet oxygen production in the reaction of superoxide with organic peroxides.

    Science.gov (United States)

    MacManus-Spencer, Laura A; Edhlund, Betsy L; McNeill, Kristopher

    2006-01-20

    [reaction: see text] A selective chemiluminescent probe for singlet oxygen has been employed to detect and quantify singlet oxygen in the reactions of superoxide with organic peroxides. The production of singlet oxygen has been quantified in the reaction of superoxide with benzoyl peroxide (BP). No singlet oxygen was detected in the reactions of superoxide with cumyl peroxide, tert-butyl peroxide, or tert-butyl hydroperoxide. On the basis of these results and on the temperature dependence of the reaction, we proposed a mechanism for singlet oxygen formation in the reaction of superoxide with BP.

  20. Solvolyses of Benzoyl Chlorides in Weakly Nucleophilic Media

    Directory of Open Access Journals (Sweden)

    Haldon Carl Harris

    2011-07-01

    Full Text Available Rate constants and activations parameters are reported for solvolyses of p-Z-substituted benzoyl chlorides (1, Z = OMe, Me, H, and Cl in 97% w/w hexafluoroisopropanol-water (97H. Additional kinetic data are reported for solvolyses in acetic and formic acids. Plots of log k vs. σp in 97H are consistent with previous research showing that a cationic reaction channel is dominant, even for solvolyses of 1, Z = NO2. A benzoyl cation intermediate was trapped by Friedel-Crafts reaction with 1,3,5-trimethoxybenzene in hexafluoroisopropanol. The results are explained by an SN2-SN1 spectrum of mechanisms with variations in nucleophilic solvent assistance. Ab initio calculations of heterolytic bond dissociation energies of various chloro- and fluoro-substituted and other benzoyl chlorides are correlated with log k for solvolyses.

  1. Microwave-assisted facile and rapid Friedel-Crafts benzoylation of arenes catalysed by bismuth trifluoromethanesulfonate

    DEFF Research Database (Denmark)

    Tran, Phoung Hoang; Hansen, Poul Erik; Pham, Thuy Than;

    2014-01-01

    The catalytic activity of metal triflates was investigated in Friedel–Crafts benzoylation under microwave irradiation. Friedel–Crafts benzoylation with benzoyl chloride of a variety of arenes containing electron-rich and electron-poor rings using bismuth triflate under microwave irradiation is de...

  2. Synthesis of N-benzoyl-N'-aryl selenoureas under PTC

    Institute of Scientific and Technical Information of China (English)

    WANG Hai; LIN Qi; ZHANG You-ming; WEI Tai-bao

    2004-01-01

    Recently many syntheses of selenium-containing compounds have been reported and studied, in which compounds selenoureas are used as the precursors for the syntheses of selenium-nitrogen heterocyclic compounds and their activities have received increasing attentions.Herein, we report the facile preparation of N-benzoyl-N'-aryl selenourea derivatives using potassium selenocyanate.In this typical procedure, Benzoyl chloride 1 was treated with potassium selenocyanate in CH2C12 under the condition of solid-liquid phase transfer catalysis using polyethylene glycal-400 as the catalyst to give the corresponding benzoyl isoselenocyanate 2. This compound did not need to be isolated and reacted with aromatic amine affording the N-benzoyl-N'-aryl selenourea derivatives 3.The reaction is described as:All the experiments were carried out under the condition of solid-liquid phase transfer catalysis using polyethylene glycal-400 as the catalyst and room temperature. And the structure was determined by IR, 1H NMR and 13C NMR. Selected data for N-benzoyl-N'-(4-fluoro)-selenourea:IR(KBr) 3426, 3274, 1672,1234,1155(C=Se); 1HMR(500MHz, DMSO) δ 12.85 (1H,S),11.86(1H,S), 7.27(2H,d,J=2.15), 7.98(2H,s,J=l.15), 7.30(2H,d,J=2.05), 7.56(2H.t,J=6.50),7.67(1H,t,J=6.20); 13C NMR(500MHz, DMSO)δ 181,168(C=Se),135,133, 132,115, 128.3, 128.8,161, 129.

  3. Preparation and characterization of N-benzoyl-O-acetyl-chitosan.

    Science.gov (United States)

    Cai, Jinping; Dang, Qifeng; Liu, Chengsheng; Fan, Bing; Yan, Jingquan; Xu, Yanyan; Li, Jingjing

    2015-01-01

    A novel amphipathic chitosan derivative, N-benzoyl-O-acetyl-chitosan (BACS), was prepared by using the selective partial acylation of chitosan (CS), benzoyl chloride, and acetic acid under high-intensity ultrasound. The chemical structure and physical properties of BACS were characterized by FTIR, (1)H NMR, TGA, and XRD techniques. The degrees of substitution of benzoyl and acetyl for the chitosan derivatives were 0.26 and 1.15, respectively, which were calculated from the peak areas in NMR spectra by using the combined integral methods. The foaming properties of CS and BACS were determined and the results suggested BACS had better foam capacity and stability than those of chitosan. In addition, the antimicrobial activities of CS and BACS were also investigated against two species of bacteria (Escherichia coli and Staphylococcus aureus) and a fungus (Aspergillus niger), the results indicated that the antibacterial and antifungal activities of BACS were much stronger than those of the parent chitosan. These findings suggested that BACS was preferable for use as a food additive with a dual role of both foaming agent and food preservative.

  4. A new silver nanorod SPR probe for detection of trace benzoyl peroxide

    Science.gov (United States)

    Jiang, Zhiliang; Wen, Guiqing; Luo, Yanghe; Zhang, Xinghui; Liu, Qingye; Liang, Aihui

    2014-06-01

    The stable silver nanorod (AgNR) sol in red was prepared by the two-step procedure of NaBH4-H2O2 and citrate heating reduction. The AgNR had a transverse and a longitudinal surface plasmon resonance (SPR) absorption peak at 338 nm and 480 nm. Meanwhile, two transverse and longitudinal SPR Rayleigh scattering (SPR-RS) peaks at 340 nm and 500 nm were observed firstly using common fluorescence spectrometer. The SPR absorption, RS, surface enhanced Raman scattering (SERS) and electron microscope technology were used to study the formation mechanism of red silver nanorods and the SERS enhancement mechanism of nano-aggregation. The AgNR-BPO SPR absorption and AgNR-NaCl-BPO SPR-RS analytical systems were studied to develop two new simple, rapid, and low-cost SPR methods for the detection of trace BPO.

  5. High chemiluminescence activity of an Fe(III)-TAML activator in aqueous-organic media and its use in the determination of organic peroxides.

    Science.gov (United States)

    Demiyanova, Alexandra S; Sakharov, Ivan Yu

    2015-05-07

    High activity of Fe(III)-TAML, peroxidase mimic, upon the catalytic oxidation of luminol in aqueous-organic media (ethanol, isopropanol and acetonitrile) was determined. Using Fe(III)-TAML the sensitive chemiluminescence assays for the determination of benzoyl peroxide and tert-butyl hydroperoxide in the presence of organic solvents were performed.

  6. Electrochemical Characterization of Benzoyl Formic Acid at Glassy Carbon Electrode in Ionic Liquid: [emim]Br

    Institute of Scientific and Technical Information of China (English)

    赵鹏; 孙茜; 王欢; 陆嘉星; 何鸣元

    2005-01-01

    The direct electrochemical reduction of benzoyl formic acid was investigated in ionic liquid, 1-ethyl-3-methyl-imidazolium bromide ([emim]Br), using cyclic voltammetry and chronocoulometry. The diffusion coefficient (D) and the transfer coefficient (α) of benzoyl formic acid in [emim]Br were obtained.

  7. A complete gear system in N-benzoyl-carbazole derivatives.

    Science.gov (United States)

    Tabata, Hidetsugu; Kayama, Susumu; Takahashi, Yuka; Tani, Norihiko; Wakamatsu, Shintaro; Tasaka, Tomohiko; Oshitari, Tetsuta; Natsugari, Hideaki; Takahashi, Hideyo

    2014-03-07

    2',6'-Disubstituted N-benzoylated carbazole derivatives were found to exhibit atropisomerism. The bulky substituents restricted rotation about the N-C7' and C7'-C1' bonds to separate four atropisomers, in which rotation about the C7'-C1' bond was in perfect concert with rotation about the N-C7' bond. Complete geared rotation without slippage at 37 °C for 7 days was observed for the first time. Conformational analysis clarified the preference for the gear system over other internal conversion pathways.

  8. STUDIES ON RADICAL POLYMERIZATION OF METHYL METHACRYLATE INITIATED WITH ORGANIC PEROXIDE-AMINE SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    QIU Kunyuan; SHUI Li; FENG Xinde

    1984-01-01

    Radical polymerization of methyl methacrylate (MMA) initiated with various diacyl peroxideamine systems was studied. Benzoyl peroxide (BPO) and lauroyl peroxide (LPO) were used as diacyl peroxide component, N,N-dimethyl aniline (DMA) and its para substituted derivatives, i.e., N,N-dimethyl-p-toluidine (DMT), p-hydroxymethyl-N,N-dimethyl aniline (HDMA), p-nitro-N,N-dimethyl aniline (NDMA) and p-dimethylamino benzaldehyde (DMAB) were used as amine components. It was found that the peroxide-DMT systems give higher rates of bulk polymerization Rp of MMA than the organic hydroperoxide-DMT systems with the following descending order BPO-DMT>LPO-DMT>CHP (cumene hydroperoxide)-DMT>TBH (tert-butyl hydroperoxide)-DMT.The aromatic tertiary amines possess obvious structural effect on the Rp values in the diacyl peroxideamine system. The overall activation energy of MMA polymerization was determined and the kinetics of polymerization of MMA initiated with BPO-DMT system was investigated.

  9. Regioselective Benzoylation of Diols and Carbohydrates by Catalytic Amounts of Organobase

    Directory of Open Access Journals (Sweden)

    Yuchao Lu

    2016-05-01

    Full Text Available A novel metal-free organobase-catalyzed regioselective benzoylation of diols and carbohydrates has been developed. Treatment of diol and carbohydrate substrates with 1.1 equiv. of 1-benzoylimidazole and 0.2 equiv. of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU in MeCN under mild conditions resulted in highly regioselective benzoylation for the primary hydroxyl group. Importantly, compared to most commonly used protecting bulky groups for primary hydroxyl groups, the benzoyl protective group offers a new protection strategy.

  10. Concentration of Hydrogen Peroxide

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  11. PRECIPITATION OF PLUTONOUS PEROXIDE

    Science.gov (United States)

    Barrick, J.G.; Manion, J.P.

    1961-08-15

    A precipitation process for recovering plutonium values contained in an aqueous solution is described. In the process for precipitating plutonium as plutonous peroxide, hydroxylamine or hydrazine is added to the plutoniumcontaining solution prior to the addition of peroxide to precipitate plutonium. The addition of hydroxylamine or hydrazine increases the amount of plutonium precipitated as plutonous peroxide. (AEC)

  12. Precursor-Directed Combinatorial Biosynthesis of Cinnamoyl, Dihydrocinnamoyl, and Benzoyl Anthranilates in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Aymerick Eudes

    Full Text Available Biological synthesis of pharmaceuticals and biochemicals offers an environmentally friendly alternative to conventional chemical synthesis. These alternative methods require the design of metabolic pathways and the identification of enzymes exhibiting adequate activities. Cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates are natural metabolites which possess beneficial activities for human health, and the search is expanding for novel derivatives that might have enhanced biological activity. For example, biosynthesis in Dianthus caryophyllus is catalyzed by hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/ benzoyltransferase (HCBT, which couples hydroxycinnamoyl-CoAs and benzoyl-CoAs to anthranilate. We recently demonstrated the potential of using yeast (Saccharomyces cerevisiae for the biological production of a few cinnamoyl anthranilates by heterologous co-expression of 4-coumaroyl:CoA ligase from Arabidopsis thaliana (4CL5 and HCBT. Here we report that, by exploiting the substrate flexibility of both 4CL5 and HCBT, we achieved rapid biosynthesis of more than 160 cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates in yeast upon feeding with both natural and non-natural cinnamates, dihydrocinnamates, benzoates, and anthranilates. Our results demonstrate the use of enzyme promiscuity in biological synthesis to achieve high chemical diversity within a defined class of molecules. This work also points to the potential for the combinatorial biosynthesis of diverse and valuable cinnamoylated, dihydrocinnamoylated, and benzoylated products by using the versatile biological enzyme 4CL5 along with characterized cinnamoyl-CoA- and benzoyl-CoA-utilizing transferases.

  13. Precursor-Directed Combinatorial Biosynthesis of Cinnamoyl, Dihydrocinnamoyl, and Benzoyl Anthranilates in Saccharomyces cerevisiae

    Science.gov (United States)

    Eudes, Aymerick; Teixeira Benites, Veronica; Wang, George; Baidoo, Edward E. K.; Lee, Taek Soon; Keasling, Jay D.; Loqué, Dominique

    2015-01-01

    Biological synthesis of pharmaceuticals and biochemicals offers an environmentally friendly alternative to conventional chemical synthesis. These alternative methods require the design of metabolic pathways and the identification of enzymes exhibiting adequate activities. Cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates are natural metabolites which possess beneficial activities for human health, and the search is expanding for novel derivatives that might have enhanced biological activity. For example, biosynthesis in Dianthus caryophyllus is catalyzed by hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/ benzoyltransferase (HCBT), which couples hydroxycinnamoyl-CoAs and benzoyl-CoAs to anthranilate. We recently demonstrated the potential of using yeast (Saccharomyces cerevisiae) for the biological production of a few cinnamoyl anthranilates by heterologous co-expression of 4-coumaroyl:CoA ligase from Arabidopsis thaliana (4CL5) and HCBT. Here we report that, by exploiting the substrate flexibility of both 4CL5 and HCBT, we achieved rapid biosynthesis of more than 160 cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates in yeast upon feeding with both natural and non-natural cinnamates, dihydrocinnamates, benzoates, and anthranilates. Our results demonstrate the use of enzyme promiscuity in biological synthesis to achieve high chemical diversity within a defined class of molecules. This work also points to the potential for the combinatorial biosynthesis of diverse and valuable cinnamoylated, dihydrocinnamoylated, and benzoylated products by using the versatile biological enzyme 4CL5 along with characterized cinnamoyl-CoA- and benzoyl-CoA-utilizing transferases. PMID:26430899

  14. Precursor-Directed Combinatorial Biosynthesis of Cinnamoyl, Dihydrocinnamoyl, and Benzoyl Anthranilates in Saccharomyces cerevisiae.

    Science.gov (United States)

    Eudes, Aymerick; Teixeira Benites, Veronica; Wang, George; Baidoo, Edward E K; Lee, Taek Soon; Keasling, Jay D; Loqué, Dominique

    2015-01-01

    Biological synthesis of pharmaceuticals and biochemicals offers an environmentally friendly alternative to conventional chemical synthesis. These alternative methods require the design of metabolic pathways and the identification of enzymes exhibiting adequate activities. Cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates are natural metabolites which possess beneficial activities for human health, and the search is expanding for novel derivatives that might have enhanced biological activity. For example, biosynthesis in Dianthus caryophyllus is catalyzed by hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/ benzoyltransferase (HCBT), which couples hydroxycinnamoyl-CoAs and benzoyl-CoAs to anthranilate. We recently demonstrated the potential of using yeast (Saccharomyces cerevisiae) for the biological production of a few cinnamoyl anthranilates by heterologous co-expression of 4-coumaroyl:CoA ligase from Arabidopsis thaliana (4CL5) and HCBT. Here we report that, by exploiting the substrate flexibility of both 4CL5 and HCBT, we achieved rapid biosynthesis of more than 160 cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates in yeast upon feeding with both natural and non-natural cinnamates, dihydrocinnamates, benzoates, and anthranilates. Our results demonstrate the use of enzyme promiscuity in biological synthesis to achieve high chemical diversity within a defined class of molecules. This work also points to the potential for the combinatorial biosynthesis of diverse and valuable cinnamoylated, dihydrocinnamoylated, and benzoylated products by using the versatile biological enzyme 4CL5 along with characterized cinnamoyl-CoA- and benzoyl-CoA-utilizing transferases.

  15. Determination of organic peroxides by liquid chromatography with on-line post-column ultraviolet irradiation and peroxyoxalate chemiluminescence detection.

    Science.gov (United States)

    Wada, Mitsuhiro; Inoue, Keiyu; Thara, Ayuko; Kishikawa, Naoya; Nakashima, Kenichiro; Kuroda, Naotaka

    2003-02-14

    A HPLC method was developed for the simultaneous determination of organic peroxides and hydrogen peroxide with peroxyoxalate chemiluminescence (PO-CL) detection following on-line UV irradiation. Organic peroxides [i.e., benzoyl peroxide (BP), tert.-butyl hydroperoxide (BHP), tert.-butyl perbenzoate (BPB), cumene hydroperoxide (CHP)] were UV irradiated (254 nm, 15 W) to generate hydrogen peroxide, which was determined by PO-CL detection. The conditions for UV irradiation and PO-CL detection were optimized by a flow injection analysis (FIA) system. Generation of hydrogen peroxide from peroxides with on-line UV irradiation also was confirmed by the FIA system by incorporating an enzyme column reactor immobilized with catalase. The separation of four organic peroxides and hydrogen peroxide by HPLC was accomplished isocratically on an ODS column within 30 min. The detection limits (signal-to-noise ratio=3) were 1.1 microM for hydrogen peroxide, 6.8 microM for BP, 31.3 microM for BHP, 7.5 microM for BPB and 1.3 microM for CHP. The proposed method was applied to the determination of BP in wheat flour.

  16. Recognizing a limitation of the TBLC-activated peroxide system on low-temperature cotton bleaching.

    Science.gov (United States)

    Chen, Wenhua; Wang, Lun; Wang, Dong; Zhang, Jingjing; Sun, Chang; Xu, Changhai

    2016-04-20

    In this study, cotton was bleached at low temperatures with an activated peroxide system which was established by incorporating a bleach activator, namely, N-[4-(triethylammoniomethyl)benzoyl]caprolactam chloride (TBCC) into an aqueous solution of hydrogen peroxide (H2O2). Experimental results showed that the bleaching performance was unexpectedly diminished as the TBCC concentration was increased over the range of 25-100g/L. Kinetic adsorption experiment indicated that this was most likely ascribed to the adsorptive interactions of TBCC and the in situ-generated compounds with cotton fibers. Such a limitation was especially fatal to cold pad-batch bleaching process of cotton in which a high TBCC concentration was often required. The results of this study may stimulate further research to avoid or overcome the limitation of the TBCC-activated peroxide system on low-temperature cotton bleaching.

  17. Chemistry of peroxide compounds

    Science.gov (United States)

    Volnov, I. I.

    1981-01-01

    The history of Soviet research from 1866 to 1967 on peroxide compounds is reviewed. This research dealt mainly with peroxide kinetics, reactivity and characteristics, peroxide production processes, and more recently with superoxides and ozonides and emphasis on the higher oxides of group 1 and 2 elements. Solid state fluidized bed synthesis and production of high purity products based on the relative solubilities of the initial, intermediate, and final compounds and elements in liquid ammonia are discussed.

  18. Organotin(IV) complexes with 2-acetylpyridine benzoyl hydrazones: antimicrobial activity

    OpenAIRE

    Despaigne,Angel A. R.; Vieira,Lorena F.; Mendes,Isolda C.; Costa,Fernanda B. da; Speziali,Nivaldo L.; Beraldo, Heloisa

    2010-01-01

    Reaction of n-butyltin trichloride, [Bu nSnCl3], and phenyltin trichloride, [PhSnCl3], with 2-acetylpyridine benzoyl hydrazone (H2AcPh), 2-acetylpyridine para-chloro-benzoyl hydrazone (H2AcpClPh) and 2-acetylpyridine para-nitro-benzoyl hydrazone (H2AcpNO2Ph) gave [Bu nSn(2AcPh)Cl2] (1), [Bu nSn(2AcpClPh)Cl2] (2), [Bu nSn(2AcpNO2Ph)Cl2] (3), [PhSn(2AcPh)Cl2] (4), [PhSn(2AcpClPh)Cl2] (5) and [PhSn(2AcpNO2Ph)Cl2] (6) as products. Among the hydrazones H2AcpClPh proved to be the most active agains...

  19. Solvolysis of benzoyl halides in water/NH4DEHP/isooctane microemulsions.

    Science.gov (United States)

    García-Río, L; Hervella, P; Rodríguez-Dafonte, P

    2006-08-29

    A study was carried out on the solvolysis reactions of different benzoyl halides in microemulsions of water/NH4DEHP/isooctane, where NH4DEHP is ammonium bis(2-ethylhexyl) phosphate. Because of the low solubility of benzoyl halides in water, they are distributed between the continuous medium and the interface of the microemulsion, where the reaction takes place. The application of the pseudophase model has allowed us to obtain the distribution constants and the rate constants at the interface for the benzoyl halides. Reaction mechanisms and the changes in these mechanisms in terms of the water content of the microemulsion have been determined on the basis of kinetic data. The influence of the substituent and the leaving group on the reaction rate has been investigated. A comparison of kinetic results with those previously obtained in water/AOT/isooctane microemulsions allows a kinetic evaluation of the change in the microemulsion properties with the surfactant.

  20. Hydrogen Peroxide Concentrator

    Science.gov (United States)

    Parrish, Clyde F.

    2007-01-01

    A relatively simple and economical process and apparatus for concentrating hydrogen peroxide from aqueous solution at the point of use have been invented. The heart of the apparatus is a vessel comprising an outer shell containing tubular membranes made of a polymer that is significantly more permeable by water than by hydrogen peroxide. The aqueous solution of hydrogen peroxide to be concentrated is fed through the interstitial spaces between the tubular membranes. An initially dry sweep gas is pumped through the interiors of the tubular membranes. Water diffuses through the membranes and is carried away as water vapor mixed into the sweep gas. Because of the removal of water, the hydrogen peroxide solution flowing from the vessel at the outlet end is more concentrated than that fed into the vessel at the inlet end. The sweep gas can be air, nitrogen, or any other gas that can be conveniently supplied in dry form and does not react chemically with hydrogen peroxide.

  1. Nucleophilic Benzoylation Using a Mandelic Acid Dioxolanone as a Synthetic Equivalent of the Benzoyl Carbanion. Oxidative Decarboxylation of α-Hydroxyacids

    Directory of Open Access Journals (Sweden)

    José R. Pedro

    2004-04-01

    Full Text Available The synthesis of alkyl aryl ketones using a mandelic acid dioxolanone as a synthetic equivalent (Umpolung of the benzoyl carbanion is reported. The methodology involves alkylation of the mandelic acid dioxolanone, hydrolysis of the dioxolanone moiety in the alkylated products and oxidative decarboxylation of the resulting α-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co (III complex in the presence of pivalaldehyde under very mild conditions.

  2. Synthesis of disubstituted homodiamantanes by acylative ring expansion using benzoyl trifluoromethanesulfonate

    Directory of Open Access Journals (Sweden)

    Takao Okazaki, Shusaku Mandai, Toshikazu Kitagawa and Ken'ichi Takeuchi

    2006-01-01

    Full Text Available Diamantane is a hydrocarbon whose carbon framework is a part of diamond lattices. Acylative ring expansion of 1- and 4-diamantanecarbaldehyde using benzoyl trifluoromethanesulfonate and trifluoromethanesulfonic acid yielded 10-hydroxyhomodiamant-9-yl benzoate and 7-hydroxyhomodiamant-8-yl benzoate, whose skeletal structures are same as pentacyclo[8.3.1.14,13.02,7.06,12]tetradecane.

  3. Copper(II)-catalyzed electrophilic amination of quinoline N-oxides with O-benzoyl hydroxylamines.

    Science.gov (United States)

    Li, Gang; Jia, Chunqi; Sun, Kai; Lv, Yunhe; Zhao, Feng; Zhou, Kexiao; Wu, Hankui

    2015-03-21

    Copper acetate-catalyzed C-H bond functionalization amination of quinoline N-oxides was achieved using O-benzoyl hydroxylamine as an electrophilic amination reagent, thereby affording the desired products in moderate to excellent yields. Electrophilic amination can also be performed in good yield on a gram scale.

  4. Rapid determination and chemical change tracking of benzoyl peroxide in wheat flour by multi-step IR macro-fingerprinting

    Science.gov (United States)

    Guo, Xiao-Xi; Hu, Wei; Liu, Yuan; Sun, Su-Qin; Gu, Dong-Chen; He, Helen; Xu, Chang-Hua; Wang, Xi-Chang

    2016-02-01

    BPO is often added to wheat flour as flour improver, but its excessive use and edibility are receiving increasing concern. A multi-step IR macro-fingerprinting was employed to identify BPO in wheat flour and unveil its changes during storage. BPO contained in wheat flour (BPO all close to 0.98. By applying second derivative spectroscopy, obvious differences among wheat flour and wheat flour contained BPO before and after storage in the range of 1500-1400 cm- 1 were disclosed. The peak of 1450 cm- 1 which belonged to BPO was blue shifted to 1453 cm- 1 (1455) which belonged to benzoic acid after one week of storage, indicating that BPO changed into benzoic acid after storage. Moreover, when using two-dimensional correlation infrared spectroscopy (2DCOS-IR) to track changes of BPO in wheat flour (0.05 mg/g) within one week, intensities of auto-peaks at 1781 cm- 1 and 669 cm- 1 which belonged to BPO and benzoic acid, respectively, were changing inversely, indicating that BPO was decomposed into benzoic acid. Moreover, another autopeak at 1767 cm- 1 which does not belong to benzoic acid was also rising simultaneously. By heating perturbation treatment of BPO in wheat flour based on 2DCOS-IR and spectral subtraction analysis, it was found that BPO in wheat flour not only decomposed into benzoic acid and benzoate, but also produced other deleterious substances, e.g., benzene. This study offers a promising method with minimum pretreatment and time-saving to identify BPO in wheat flour and its chemical products during storage in a holistic manner.

  5. Rapid determination and chemical change tracking of benzoyl peroxide in wheat flour by multi-step IR macro-fingerprinting.

    Science.gov (United States)

    Guo, Xiao-Xi; Hu, Wei; Liu, Yuan; Sun, Su-Qin; Gu, Dong-Chen; He, Helen; Xu, Chang-Hua; Wang, Xi-Chang

    2016-02-01

    BPO is often added to wheat flour as flour improver, but its excessive use and edibility are receiving increasing concern. A multi-step IR macro-fingerprinting was employed to identify BPO in wheat flour and unveil its changes during storage. BPO contained in wheat flour (BPO all close to 0.98. By applying second derivative spectroscopy, obvious differences among wheat flour and wheat flour contained BPO before and after storage in the range of 1500-1400 cm(-1) were disclosed. The peak of 1450 cm(-1) which belonged to BPO was blue shifted to 1453 cm(-1) (1455) which belonged to benzoic acid after one week of storage, indicating that BPO changed into benzoic acid after storage. Moreover, when using two-dimensional correlation infrared spectroscopy (2DCOS-IR) to track changes of BPO in wheat flour (0.05 mg/g) within one week, intensities of auto-peaks at 1781 cm(-1) and 669 cm(-1) which belonged to BPO and benzoic acid, respectively, were changing inversely, indicating that BPO was decomposed into benzoic acid. Moreover, another autopeak at 1767 cm(-1) which does not belong to benzoic acid was also rising simultaneously. By heating perturbation treatment of BPO in wheat flour based on 2DCOS-IR and spectral subtraction analysis, it was found that BPO in wheat flour not only decomposed into benzoic acid and benzoate, but also produced other deleterious substances, e.g., benzene. This study offers a promising method with minimum pretreatment and time-saving to identify BPO in wheat flour and its chemical products during storage in a holistic manner.

  6. 75 FR 9767 - Classification of Benzoyl Peroxide as Safe and Effective and Revision of Labeling to Drug Facts...

    Science.gov (United States)

    2010-03-04

    ... the results and extrapolate to human use. The relevance of the animal tumor promoter study results to... to Drug Facts Format; Topical Acne Drug Products for Over-The-Counter Human Use; Final Rule AGENCY... Panel on OTC Antimicrobial (II) Drug Products SKU: Stock Keeping Unit--an identifier that is used...

  7. The Crystal Structure of N-Benzoyl-N'-(2-hydroxyethyl)-thiourea

    Institute of Scientific and Technical Information of China (English)

    XIAN Liang; ZHANG You-ming; WEI Tai-bao

    2004-01-01

    Thiourea compounds are excellent agents of bioactive substance. A number of biological activities are associated with substituted thiourea derivatives. A survey of literature reveals that some work has been reported on benzoylthiourea, which has found plenty of applications as a facile and simple ligand in determination of trances of the transition metal and as an available starting material in preparation of a wide variety of metal complexes. In recent years,N-benzoyl-N'-(2-hydroxyethyl)-thiourea has attracted considerable attention as selective reagents for the liquid-liquid extraction and preconcentration of platinum group metals and its antifungle activity.As a part of our works in studying coordination behaviours of N-benzoyl-N'-(2-hydroxyethyl)-thiourea and its bioactivity, in view of these observations and in continuation of our previous works on it, the present work was reported on the crystal structure of N-benzoyl-N'-( 2-hydroxyethyl)-thiourea.The crystals structure in the monoclinic system and space group of P21/c of N-benzoyl-N'-(2-hydroxyethyl)- thiourea (C10H12N2O2S) was determined from single-crystal X-ray diffraction analysis, a = 17.083 (3) A, b = 4.5490 (10) A, c = 14.279 (3)A, a = 90.00°, a = 102.44(3)°, a = 90.00 °, Ⅴ = 1083.6 (4)A3, Z = 4, Dc = 1.375 Mg/m3, i (Mo Ka)= 0.280 mm-1, F(000) =472. The final R and u R are 0.0399 and 0.0881 for 783 observed reflections [Ⅰ>26(Ⅰ)].Fig. 1 shows the molecular crystal structure of N-benzoyl-N'-(2-hydroxyethyl)thiourea indicating that the carbonyl and thiocarbonyl moieties are pointing in approximate opposite directions. The six atoms in the ring structure hydrogen bonded are almost in one plane. The N(2)-H proton pendant arm extends to the carbonyl oxygen atom, forms hydrogen bond between them.The existence of hydrogen bond in benzoyl-thiourea molecular six-membered ring structure has significant implications on coordination properties, suggest the possibility of intramolecular hydrogen bond

  8. Hydrogen peroxide catalytic decomposition

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2010-01-01

    Nitric oxide in a gaseous stream is converted to nitrogen dioxide using oxidizing species generated through the use of concentrated hydrogen peroxide fed as a monopropellant into a catalyzed thruster assembly. The hydrogen peroxide is preferably stored at stable concentration levels, i.e., approximately 50%-70% by volume, and may be increased in concentration in a continuous process preceding decomposition in the thruster assembly. The exhaust of the thruster assembly, rich in hydroxyl and/or hydroperoxy radicals, may be fed into a stream containing oxidizable components, such as nitric oxide, to facilitate their oxidation.

  9. Electrochemical Hydrogen Peroxide Generator

    Science.gov (United States)

    Tennakoon, Charles L. K.; Singh, Waheguru; Anderson, Kelvin C.

    2010-01-01

    Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions. The innovation focuses on the in situ generation of hydrogen peroxide using an electrochemical cell having a gas diffusion electrode as the cathode (electrode connected to the negative pole of the power supply) and a platinized titanium anode. The cathode and anode compartments are separated by a readily available cation-exchange membrane (Nafion 117). The anode compartment is fed with deionized water. Generation of oxygen is the anode reaction. Protons from the anode compartment are transferred across the cation-exchange membrane to the cathode compartment by electrostatic attraction towards the negatively charged electrode. The cathode compartment is fed with oxygen. Here, hydrogen peroxide is generated by the reduction of oxygen. Water may also be generated in the cathode. A small amount of water is also transported across the membrane along with hydrated protons transported across the membrane. Generally, each proton is hydrated with 3-5 molecules. The process is unique because hydrogen peroxide is formed as a high-purity aqueous solution. Since there are no hazardous chemicals or liquids used in the process, the disinfection product can be applied directly to water, before entering a water filtration unit to disinfect the incoming water and to prevent the build up of heterotrophic bacteria, for example, in carbon based filters. The competitive advantages of this process are: 1. No consumable chemicals are needed in the process. The only raw materials

  10. Synthesis and characterization of bio-based polyurethane from benzoylated cashewnut husk tannins

    Indian Academy of Sciences (India)

    A J Sunija; S Siva Ilango; K P Vinod Kumar

    2014-05-01

    Benzoylated tannin prepared by benzoylation of cashewnut husk tannin, was treated with hexame-thylenediisocyanate in the presence of 1,4-butanediol as an extender to prepare thermosetting polyurethane. The sample was characterized using FT–IR and 13C NMR spectra. Thermal, morphological, physico-chemical and electrical properties were also investigated. Polyurethane obtained was sensitive to moisture but had very good solvent resistance. Results show that g of the sample is 260 °C and thermal decomposition begins at 280 °C. The dielectric constant varies randomly with temperature. The conductivity of the sample was found to increase with increase in temperature but shows random variation at 90 and 150 °C

  11. Design, Synthesis and Biological Activities of Novel Benzoyl Hydrazines Containing Pyrazole

    Institute of Scientific and Technical Information of China (English)

    闫涛; 于淑晶; 刘鹏飞; 刘卓; 王宝雷; 熊丽霞; 李正名

    2012-01-01

    In search of environmentally benign compounds with high biological activity, low toxicity and low resistance, 8 novel benzoyl hydrazines containing pyrazole were designed and synthesized. All compounds were characterized by I H NMR spectra and HRMS. The preliminary results of biological activity assessment indicated that most of title compounds exhibited certain insecticidal activities against M),thimna separata Walker at 200 mg L-1 but excellent fungicidal activities against six fungus at 50 mg L-1, which were better than the control.

  12. PREPARATION, CHARACTERIZATION AND ADHESIVE PROPERTIES OF DI-AND TRI-HYDROXY BENZOYL CHITOSAN NANOPARTICLES

    Institute of Scientific and Technical Information of China (English)

    Mohamad Taghi Taghizadeh; Ali Bahadori

    2013-01-01

    Modified chitosans with 3,4-di-hydroxy benzoyl groups (CS-DHBA) and 3,4,5-tri-hydroxy benzoyl groups (CSTHBA) were synthesized and their nanoparticles were prepared via ionic crosslinking by tripolyphosphate (TPP).The chemical structure and degree of substitution (DS) of di-and tri-hydroxy benzoyl chitosans are determined by FTIR and 1HNMR spectroscopy.The morphology of particles,size distribution and zeta potential of nanoparticles were studied using transmission electron microscopy (TEM) and dynamic light scattering (DLS),respectively.The mean diameters of particles of CS-DHBA and CS-THBA nanoparticles were 144 nm and 112 nm,respectively.It was found that the particles size decreased slightly with decreasing the degree of substitution and increasing degree of deacetylation (DD),due to increasing of ionic crosslinking of ammonium ions and polyanions of tripolyphosphate.The TEM photographs of CS-DHBA show that these particles are spherical in shape,but the particles of CS-THBA show some aggregation.In addition,the solubility and the mechanical properties of the prepared modified chitosans and their nanoparticles were evaluated for bio-adhesive and biomedical application.The results of solubility tests indicated that,the CS-DHBA and CS-THBA have higher solubility at pH > 7 comparing to CS.Also the CS-DHBA,CS-THBA and their nanoparticles showed a significant adhesive capacity and enhanced tensile strength and tensile modulus.

  13. Organotin(IV) complexes with 2-acetylpyridine benzoyl hydrazones: antimicrobial activity

    Energy Technology Data Exchange (ETDEWEB)

    Despaigne, Angel A.R.; Vieira, Lorena F.; Mendes, Isolda C.; Costa, Fernanda B. da; Beraldo, Heloisa, E-mail: hberaldo@ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Speziali, Nivaldo L. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica

    2010-07-01

    Reaction of n-butyltin trichloride, [Bu{sup n}SnCl{sub 3}], and phenyltin trichloride, [PhSnCl{sub 3}], with 2-acetylpyridine benzoyl hydrazone (H2AcPh), 2-acetylpyridine para-chloro-benzoyl hydrazone (H2AcpClPh) and 2-acetylpyridine para-nitro-benzoyl hydrazone (H2AcpNO{sub 2}Ph) gave [Bu{sup n}Sn(2AcPh)Cl{sub 2}] (1), [Bu{sup n}Sn(2AcpClPh)Cl{sub 2}] (2), [Bu{sup n}Sn(2AcpNO{sub 2}Ph)Cl{sub 2}] (3), [PhSn(2AcPh)Cl{sub 2}] (4), [PhSn(2AcpClPh)Cl{sub 2}] (5) and [PhSn(2AcpNO{sub 2}Ph)Cl{sub 2}] (6) as products. Among the hydrazones H2AcpClPh proved to be the most active against Staphylococcus aureus and Candida albicans. Upon coordination the antibacterial activity of both tin and the hydrazones significantly increases. Complexes 2 and 5 revealed to be the most active as antimicrobial agents. (author)

  14. LIPID PEROXIDATION IN PREECLAMPSIA

    Directory of Open Access Journals (Sweden)

    T.Sharmila Krishna

    2015-03-01

    Full Text Available Hypertension in pregnancy is a leading cause of both maternal and fetal mortality and morbidity. Preeclampsia is characterised by hypertension and proteinuria. Lipid peroxidation is an important factor in the pathophysiology of Preeclampsia. The present study was undertaken to determine Serum Malondialdehyde (MDA levels , a product of lipid peroxidation , in clinically diagnosed Preeclamptic women(n=30 and the values were compared with that of Normotensive pregnant women (n=30 aged between 18-30yrs. All of them were in their third trimester and were primigravida. Serum MDA was estimated by TBARS (thiobarbituric acid reactive substances method. We observed that Serum MDA levels were significantly increased in Preeclamptic women (p <0.000 as compared to that of Normotensive pregnant women . Increased levels of lipid peroxiation product - MDA may contribute to the pathophysiology of Preeclampsia.

  15. Protein oxidation and peroxidation

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan

    2016-01-01

    and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function....... Unlike H2O2, which is rapidly removed by protective enzymes, protein peroxides are only slowly removed, and catabolism is a major fate. Although turnover of modified proteins by proteasomal and lysosomal enzymes, and other proteases (e.g. mitochondrial Lon), can be efficient, protein hydroperoxides...

  16. Greener Friedel-Crafts Acylation using Microwave-enhanced reactivity of Bismuth Triflate in the Friedel-Crafts Benzoylation of Aromatic Compounds with Benzoic Anhydride

    DEFF Research Database (Denmark)

    Tran, Phuong Hoang; Nguyen, hai Truong; Hansen, Poul Erik

    2017-01-01

    An efficient and facile bismuth trifluoromethanesulfonate-catalyzed benzoylation of aromatic compounds using benzoic anhydride under solvent-free microwave irradiation has been developed. The microwave-assisted Friedel-Crafts benzoylation results in good yields within short reaction times. Bismut...

  17. A novel surfactant S-benzoyl-N,N-diethyldithiocarbamate synthesis and its flotation performance to galena

    Science.gov (United States)

    Ma, Xin; Hu, Yuan; Zhong, Hong; Wang, Shuai; Liu, Guangyi; Zhao, Gang

    2016-03-01

    In this paper, a novel dithiocarbamate compound, S-benzoyl-N,N-diethyldithiocarbamate (BEDTC), was synthesized via one-pot reaction of diethylamine, carbon disulfide, sodium hydroxide and benzoyl chloride using abundant carbon disulfide as a solvent. Its flotation performance and adsorption mechanism on the galena was first investigated by flotation tests, adsorption quantity measurements, FTIR spectra, X-ray photoelectron spectra (XPS) and density functional theory (DFT) calculation. The flotation results illustrated that BEDTC exhibited stronger collecting power than the conventional sulphide collectors such as sodium diethyl dithiocarbamate (SEDTC) and sodium isobutyl xanthate (SIBX) and superior selectivity for galena against sphalerite. The adsorption data demonstrated that the adsorption affinity of BEDTC to galena was stronger than that of SEDTC and SIBX, and the preferable pH range for BEDTC adsorption on galena surfaces was 6-10. The results of FTIR spectra and XPS indicated that the interaction of BEDTC with galena may be dominated by the chemical adsorption, which was further confirmed by DFT calculation. BEDTC probably acted as a bidentate ligand, bonding with lead through the thiol sulfur and carbonyl oxygen atoms to form two distinct adsorption geometries, one with the same Pb atom to form a six-membered ring complex, and the other with two different Pb atoms to form a "bullet" shape complex.

  18. n-Benzoyl-n-phenylhydroxylamine impregnated Amberlite XAD-4 beads for selective removal of thorium

    Energy Technology Data Exchange (ETDEWEB)

    Chandramouleeswaran, S.; Ramkumar, Jayshree, E-mail: jrk@barc.gov.in

    2014-09-15

    Highlights: • XAD-4 was impregnated with a commonly used gravimetric agent n-benzoyl-n-phenylhydroxylamine. • Sorbent characterized by different techniques to understand the pore filling of XAD-4. • Sorption of Th was fast (30 min) and unaffected by initial solution pH. • Selectivity achieved by tuning the conditions of the mixture solution. - Abstract: n-Benzoyl-n-phenylhydroxylamine impregnated Amberlite XAD-4 beads were used for the removal of Th(IV) from a mixture of ions. The impregnated XAD was characterized using different techniques like weight and colour change, IR spectra, surface area and pore size measurements to confirm the presence of n-BPHA within the macroreticular resin structure. The experimental conditions were optimized to make the separation fast and selective. It was seen that the maximum sorption was achieved in the pH range of 3–7.5 and uptake was nearly complete within half an hour. The results obtained in the present study were subjected to extensive modelling in order to get a complete understanding of the sorption process. It is seen that the maximum uptake was calculated to be 500 mg/g and has very fast kinetics it was seen that the process is chemisorption. It was further deduced from the modelling that the overall sorption process was controlled dominantly by external mass transfer. Considering the simplicity this procedure, the present study has a possible application for the removal of thorium from different mixtures.

  19. Synthesis and Characterization of Polycarbonate Copolymers Containing Benzoyl Groups on the Side Chain for Scratch Resistance

    Directory of Open Access Journals (Sweden)

    Hohyoun Jang

    2016-01-01

    Full Text Available The purpose of this study was to enhance the scratch resistance of polycarbonate copolymer by using 3,3′-dibenzoyl-4,4′-dihydroxybiphenyl (DBHP monomer, containing benzoyl moieties on the ortho positions. DBHP monomer was synthesized from 4,4′-dihydroxybiphenyl and benzoyl chloride, followed by the Friedel-Craft rearrangement reaction with AlCl3. The polymerizations were conducted following the low-temperature procedure, which is carried out in methylene chloride by using triphosgene, triethylamine, bisphenol-A, and DBHP. The chemical structures of the polycarbonate copolymers were confirmed by 1H-NMR. The thermal properties of copolymers were investigated by thermogravimetric analysis and differential scanning calorimetry, and also surface morphologies were assessed by atomic force microscopy. The scratch resistance of homopolymer film (100 μm changed from 6B to 1B, and the contact angle of a sessile water drop onto the homopolymer film also increased.

  20. Novel antimicrobial superporous cross-linked chitosan/pyromellitimide benzoyl thiourea hydrogels.

    Science.gov (United States)

    Mohamed, Nadia A; Abd El-Ghany, Nahed A; Fahmy, Mona M

    2016-01-01

    In this work, chitosan (CS) was cross-linked with different amounts of pyromellitimide benzoyl thiourea moieties. The structure of the cross-linked CS was confirmed by elemental analyses, FTIR and (1)H- NMR spectroscopy. The cross-linking process proceeds via reacting of the amino groups of CS with the isothiocyanate groups of the N,N'-bis [4-(isothiocyanate carbonyl)phenyl] pyromellitimide cross-linker. The amount of the cross-linker was varied with respect to CS to produce four new pyromellitimide benzoyl thiourea cross-linked CS (PIBTU-CS) hydrogels designated as PIBTU-CS-1, PIBTU-CS-2, PIBTU-CS-3, and PIBTU-CS-4 of increasing cross-linking degree percent of 11, 22, 44 and 88%, respectively. The scanning electron microscopy observation indicates the extremely porous structure of the hydrogels. XRD results showed that the crystallinity of CS was decreased upon cross-linking. The four hydrogels exhibit a higher antibacterial activity on Bacillus subtilis and Streptococcus pneumoniae as Gram positive bacteria and against Escherichia coli as Gram negative bacteria and higher antifungal activity on Aspergillus fumigatus, Syncephalastrum racemosum and Geotricum candidum than that of the parent CS as shown from their higher inhibition zone diameters and their lower MIC values. The swell ability of the hydrogel as well as their antimicrobial activity increased with increasing cross-linking density.

  1. 2-Benzoyl-6-benzylidenecyclohexanone analogs as potent dual inhibitors of acetylcholinesterase and butyrylcholinesterase.

    Science.gov (United States)

    Leong, Sze Wei; Abas, Faridah; Lam, Kok Wai; Shaari, Khozirah; Lajis, Nordin H

    2016-08-15

    In the present study, a series of 2-benzoyl-6-benzylidenecyclohexanone analogs have been synthesized and evaluated for their anti-cholinesterase activity. Among the forty-one analogs, four compounds (38, 39, 40 and 41) have been identified as lead compounds due to their highest inhibition on both AChE and BChE activities. Compounds 39 and 40 in particular exhibited highest inhibition on both AChE and BChE with IC50 values of 1.6μM and 0.6μM, respectively. Further structure-activity relationship study suggested that presence of a long-chain heterocyclic in one of the rings played a critical role in the dual enzymes' inhibition. The Lineweaver-Burk plots and docking results suggest that both compounds could simultaneously bind to the PAS and CAS regions of the enzyme. ADMET analysis further confirmed the therapeutic potential of both compounds based upon their high BBB-penetrating. Thus, 2-benzoyl-6-benzylidenecyclohexanone containing long-chain heterocyclic amine analogs represent a new class of cholinesterase inhibitor, which deserve further investigation for their development into therapeutic agents for cognitive diseases such as Alzheimer.

  2. Selective Monohydrocyanation of Diimine using Potassium Hexacyanoferrate(II)-Benzoyl Chloride Reagent System as a Cyanide Source

    Indian Academy of Sciences (India)

    ZHENG LI; FEI WEN; JINGYA YANG

    2016-12-01

    The selective monohydrocyanation of diimines using potassium hexacyanoferrate(II)-benzoyl chloride reagent system as a cyanide source under catalyst-free condition is described. The advantages of this protocol are the non-toxic, non-volatile and inexpensive cyanide source, high yield, and simple work-up procedure.

  3. Exposure of mouse skin to organic peroxides: subchronic effects related to carcinogenic potential.

    Science.gov (United States)

    Hanausek, Margaret; Walaszek, Zbigniew; Viaje, Aurora; LaBate, Michael; Spears, Erick; Farrell, David; Henrich, Richard; Tveit, Ann; Walborg, Earl F; Slaga, Thomas J

    2004-03-01

    Screening of newly synthesized organic peroxides for tumor initiating/promoting activity would be greatly facilitated if predictive methodologies could be developed using topical exposures shorter than those required for definitive tumor assessment in mouse skin models. Nine organic peroxides [benzoyl peroxide (BZP), di-t-butyl peroxide (DTBP), t-butyl peroxybenzoate (TBPB), p-t-butyl isopropylbenzene hydroperoxide (TBIBHP), cumene hydroperoxide (CHP), dicetyl peroxydicarbonate (DPD), dicumyl peroxide (DCP), methyl ethyl ketone peroxide (MEKP) and O,O-t-butyl-O-(2-ethylhexyl) monoperoxycarbonate (TBEC)] were evaluated for their ability to increase biomarkers of tumor promotion in mouse skin, i.e. sustained epidermal hyperplasia, dermal inflammation and oxidative DNA damage. Evaluations were performed using SENCAR mice exposed topically for 4 weeks. The organic peroxides varied in their effects on these biomarkers. BZP, TBPB and TBIBHP exhibited significant increases in all three biomarkers associated with tumor promoting activity, CHP produced increases only in sustained epidermal hyperplasia and dermal inflammation, MEKP and DCP produced increases only in sustained epidermal hyperplasia and TBEC produced an increase only in dermal inflammation. DTBP and DPD had no effect on the three parameters studied. TBPB and TBIBHP were selected for further examination of their ability to produce mutations in codons 12, 13 and 61 of the c-Ha-ras protooncogene, i.e. those mutations known to be involved in the initiation of mouse skin tumors, because they were the only peroxides to exhibit significant positive results in all assays except the Ha-ras mutation following 4 weeks of exposure. Evaluations were performed using SENCAR mice dosed topically for 8 or 12 weeks in a complete carcinogenesis protocol or 16 weeks in an initiation/promotion protocol using 7,12-dimethylbenz[a]anthracene, urethane, benzo[a]pyrene and N-methyl-N'-nitro-N-nitrosoguanidine as positive controls

  4. Synergistic extraction of trivalent lanthanoids with 3-phenyl-4-benzoyl-5-isoxazolone and various sulphoxides

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, S.K.; Chakravortty, V. [Utkal Univ., Bhubaneswar (India). Dept. of Chemistry; Reddy, M.L.P.; Ramamohan, T.R. [Council of Scientific and Industrial Research, Trivandrum (India). Regional Research Lab.

    1999-07-01

    Synergistic extraction of trivalent lanthanoids Nd, Tb and Tm with mixtures of 3-phenyl-4-benzoyl-5-isoxazolone (HPBI) and dioctyl sulphoxide (DOSO), bis-2-ethylhexyl sulphoxide (B2EHSO) or diphenyl sulphoxide (DPhSO) in xylene from perchlorate solution was investigated. Lanthanoids were found to be extracted as Ln(PBI){sub 3} with HPBI alone. In the presence of sulphoxides, Nd(III) was found to be extracted as Nd(PBI){sub 3} . S and Nd(PBI){sub 3} . 2 S (where S = sulphoxide). On the other hand, Tb(III) and Tm(III) were extracted as Tb(PBI){sub 3} . S and Tm(PBI){sub 3} . S respectively. The equilibrium constants of the synergistic species were found to increase monotonically with decreasing ionic radii of these metal ions. The addition of a sulphoxide to the metal chelate system not only enhances the extraction efficiency but also improves the selectivities among these trivalent lanthanoids. (orig.)

  5. Development of N-ferrocenyl(benzoyl)amino-acid esters stationary phase for high performance liquid chromatography.

    Science.gov (United States)

    Zhou, Xiaohua; Li, Xiaole; Cao, Aijuan; Lijun, Qiao; Yu, Ajuan; Zhang, Shusheng; Wu, Yangjie

    2015-11-01

    A new stationary phase for high-performance liquid chromatography was prepared by covalently bonding N-ferrocenyl(benzoyl)amino-acid esters (L(1)) onto silica gel using 3-aminopropyltriethoxysilane as coupling reagent. The structure of new material was characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. The chromatographic behavior of the phase was illustrated in reversed-phase (RP) and normal-phase (NP) modes using polycyclic aromatic hydrocarbons (PAHs), aromatics positional isomers, amines, 5-nitroimidazoles, organophosphorus pesticides and phenols as probes. Multiple mechanisms including hydrophobic, hydrogen bonding, π-π, dipole-dipole, charge-transfer and acid-base equilibrium interactions are involved. Thus, multi-interaction mechanisms and mixed-mode separation of the new phase can very likely guarantee its excellent chromatographic performance for the analysis of complex samples. The L(1) AminoSil column was successfully employed for the analysis of organophosphorus pesticides in vegetable.

  6. Identification of Minor Benzoylated 4-Phenylcoumarins from a Mammea neurophylla Bark Extract

    Directory of Open Access Journals (Sweden)

    Bach Tai Dang

    2015-09-01

    Full Text Available Through dereplication analysis, seven known Mammea coumarins were identified in a fraction obtained from Mammea neurophylla dichloromethane bark extract selected for its ability to prevent advanced glycation end-product (AGE formation. Among them, a careful examination of the NMR dataset of pedilanthocoumarin B led to a structural revision. Inspection of LC-DAD-MSn chromatograms allowed us to predict the presence of four new compounds, which were further isolated. Using spectroscopic methods (1H-, 13C- and 2D-NMR, HRMS, UV, these compounds were identified as new benzoyl substituted 4-phenylcoumarins (iso-pedilanthocoumarin B and neurophyllol C and 4-(1-acetoxypropylcoumarins cyclo F (ochrocarpins H and I.

  7. Synthesis of 1-O-(2'-acetoxy)benzoyl-alpha-D-2-deoxyglucopyranose, a novel aspirin prodrug.

    Science.gov (United States)

    Truelove, J E; Hussain, A A; Kostenbauder, H B

    1980-02-01

    The synthesis and characterization of 1-O-(2'-acetoxy)benzoyl-alpha-D-2-deoxyglucopyranose, a novel aspirin prodrug, are described. 3,4,6-Tri-O-benzyl-alpha-D-2-deoxyglucopyranose was synthesized by methylating the anomeric hydroxyl group of 2-deoxyglucose, benzylating the 3-, 4-, and 6-hydroxy functional grups, and cleaving hydrolytically the anomeric methyl group. Reaction of the tribenzylated sugar with the acid chloride of aspirin and subsequent hydrogenolysis of the benzyl groups resulted in the prodrug, mp 128 degrees. The compound was further characterized by elemental analysis and PMR and 13C-NMR spectroscopy. In vitro, the compound cleaved to aspirin with a half-life of 7 min at 37 degrees. Prodrug cleavage was independent of pH over the pH 3--9 range.

  8. Ultrasonic degradation of N-di and trihydroxy benzoyl chitosans and its effects on antioxidant activity.

    Science.gov (United States)

    Taghizadeh, Mohamad Taghi; Bahadori, Ali

    2014-05-01

    Modified chitosans with 3,4-dihydroxy benzoyl groups (CS-DHBA) and 3,4,5-trihydroxy benzoyl groups (CS-THBA) were synthesized and their chemical structures were determined by Fourier transform infrared (FT-IR) and (1)H nuclear magnetic resonance ((1)H NMR) spectroscopy. Then, ultrasonic degradation of CS, CS-DHBA and CS-THBA in 1% acetic acid solution was investigated. The kinetics studies of degradation were followed by gel permeation chromatography (GPC). The results indicated that the weight-average molecular weight of chitosan decreased obviously after ultrasound treatment, but molecular weights of CS-DHBA and CS-THBA decreased slowly with increasing sonication time. Degradation kinetics model based on 1/Mt-1/M0=kt was used to estimate the degradation rate constant. It was found that the rates of degradation of CS-DHBA and CS-THBA are lower than CS, and follow the order: CS4>CS8>CS12>CS-THBA4>CS-THBA8 ≈ CS-DHBA4>CS-THBA12>CS-DHBA8>CS-DHBA12. The antioxidant activity of the CS, CS-DHBA and CS-THBA before and after sonication was investigated by the radical scavenging activity method using 1,1-diphenyl-2-picrylhydrazyl (DPPH). The DPPH scavenging free radical capacity of CS-THBA and CS-DHBA increased up to 89% and 74% respectively, when the concentration reached 6 μg/ml. The ultrasonic treatment of CS-DHBA and CS-THBA after 30 min decreased the DPPH free radical scavenging activity but ultrasonic treatment of CS increased the DPPH free radical scavenging activity.

  9. A novel surfactant S-benzoyl-N,N-diethyldithiocarbamate synthesis and its flotation performance to galena

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xin; Hu, Yuan; Zhong, Hong, E-mail: zhongh@csu.edu.cn; Wang, Shuai, E-mail: wangshuai@csu.edu.cn; Liu, Guangyi; Zhao, Gang

    2016-03-01

    Graphical abstract: - Highlights: • A novel surfactant BEDTC was first introduced as galena flotation collector. • BEDTC exhibited superior collecting power to galena against sphalerite. • BEDTC has two active centers to mineral surfaces. • BEDTC molecules formed two distinct adsorption geometries on galena surfaces. - Abstract: In this paper, a novel dithiocarbamate compound, S-benzoyl-N,N-diethyldithiocarbamate (BEDTC), was synthesized via one-pot reaction of diethylamine, carbon disulfide, sodium hydroxide and benzoyl chloride using abundant carbon disulfide as a solvent. Its flotation performance and adsorption mechanism on the galena was first investigated by flotation tests, adsorption quantity measurements, FTIR spectra, X-ray photoelectron spectra (XPS) and density functional theory (DFT) calculation. The flotation results illustrated that BEDTC exhibited stronger collecting power than the conventional sulphide collectors such as sodium diethyl dithiocarbamate (SEDTC) and sodium isobutyl xanthate (SIBX) and superior selectivity for galena against sphalerite. The adsorption data demonstrated that the adsorption affinity of BEDTC to galena was stronger than that of SEDTC and SIBX, and the preferable pH range for BEDTC adsorption on galena surfaces was 6–10. The results of FTIR spectra and XPS indicated that the interaction of BEDTC with galena may be dominated by the chemical adsorption, which was further confirmed by DFT calculation. BEDTC probably acted as a bidentate ligand, bonding with lead through the thiol sulfur and carbonyl oxygen atoms to form two distinct adsorption geometries, one with the same Pb atom to form a six-membered ring complex, and the other with two different Pb atoms to form a ''bullet'' shape complex.

  10. 21 CFR 529.1150 - Hydrogen peroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide... group. Eggs: Some strains of rainbow trout eggs are sensitive to hydrogen peroxide treatment at a...

  11. The biosynthesis of phytoalexins in Dianthus caryophyllus L. cell cultures: induction of benzoyl-CoA:anthranilate N-benzoyltransferase activity.

    Science.gov (United States)

    Reinhard, K; Matern, U

    1989-11-15

    It has been shown that cell cultures of Dianthus caryophyllus L. c.v. Eleganz accumulate N-benzoyl-4-methoxyanthranilic acid, previously identified as the phytoalexin methoxydianthramide B, in response to treatment either with a crude elicitor isolated from the cell walls of Phytophthora megasperma f.sp. glycinea or with a commercial yeast extract. Cell-free extracts from the induced cells efficiently catalyzed the N-benzoylation of anthranilate in the presence of benzoyl-CoA. The partially purified transferase was shown to be specific for anthranilate with almost no activity toward 4-hydroxyanthranilate, whereas acyl donors other than benzoyl-CoA such as salicyloyl-, cinnamoyl-, or 4-coumaroyl-CoA were also accepted. Elicitor treatment of the cells additionally induced an S-adenosyl-L-methionine:N-benzoyl-4-hydroxyanthranilate 4-O-methyltransferase activity. We propose, therefore, that methoxydianthramide B is derived from N-benzoylanthranilic acid via N-benzoyl-4-hydroxyanthranilic acid. Dark-grown cells contained little N-benzoyltransferase activity (approx 8 mu kat/kg), which increased roughly ninefold within 6 h following the addition of the elicitor. In addition, phenylalanine ammonia-lyase activity of the cells increased about twofold under these conditions to a maximum (approx 40 mu kat/kg) at 5 h. The rapid induction of both enzyme activities suggests that the shikimate pathway is of crucial importance in the disease resistance response of carnation cells.

  12. EFIKASI LARVASIDA BERBAHAN AKTIF BENZOYL PHENIL UREA SEBAGAI INSECT GROWTH REGULATOR TERHADAP LARVA Culex quinquefasciatus DI LABORATORIUM

    Directory of Open Access Journals (Sweden)

    Siti Alfiah

    2014-06-01

    Full Text Available This study was conducted to determine the efficacy of an insect growth regulator (IGRbenzoyl phenil urea against Culex quinquefasciatus larvae, laboratory scale trial. The researchused seven concentrations of IGR, were evaluated 0,5 ; 1 ; 2 ; 2,5 ; 3 and 5 ppm and untreatedcontrol, using 4 replications (20 larvae each. The result showed that 0,5 ppm of the benzoylphenil urea could kill more 90% of Cx. quinquefasciatus larvae in 5 days, while concentrations 1; 2 ; 2,5 and 3 ppm in 4 days, and concentration 5 ppm in 3 days. The result was also revealedthat LC50 and LC90 0,57 and 23,2 ppm. Mosquito larvae mortalities were showed statisticallydifferent among concentrations (p < 0,05.Key words : Efficacy, benzoyl phenil urea, Culex quinquefasciatus Penelitian untuk mengetahui efikasi insect growth regulator (IGR benzoyl phenil ureaterhadap larva Culex quinquefasciatus telah dilakukan. Penelitian menggunakan 7 konsentrasipengujian yaitu 0,5 ppm, 1 ppm, 2 ppm, 2,5 ppm, 3 ppm, 5 ppm dan kontrol. Setiap konsentrasimenggunakan 4 kali pengulangan. Hasil menunjukkan bahwa larvasida benzoyl phenil ureamembunuh lebih dari 90% larva Cx. quinquefasciatus dengan konsentrasi 0,5 ppm dalam 5 hari,konsentrasi 1 ; 2 ; 2,5 dan 3 ppm dalam waktu 4 hari dan konsentrasi 5 ppm dalam waktu 3 hari.Konsentrasi yang diperlukan untuk membunuh 50% (LC50 dan 90% (LC90 larva uji adalah 0,57ppm dan 23,2 ppm. Uji analisis varian memberikan hasil bahwa ada perbedaan bermaknakematian larva antar konsentrasi pada taraf nyata 5%.Kata kunci : Efikasi, benzoyl phenil urea, Culex quinquefasciatus

  13. Probing the reactivity of photoinitiators for free radical polymerization: time-resolved infrared spectroscopic study of benzoyl radicals.

    Science.gov (United States)

    Colley, Christopher S; Grills, David C; Besley, Nicholas A; Jockusch, Steffen; Matousek, Pavel; Parker, Anthony W; Towrie, Michael; Turro, Nicholas J; Gill, Peter M W; George, Michael W

    2002-12-18

    A series of substituted benzoyl radicals has been generated by laser flash photolysis of alpha-hydroxy ketones, alpha-amino ketones, and acyl and bis(acyl)phosphine oxides, all of which are used commercially as photoinitiators in free radical polymerizations. The benzoyl radicals have been studied by fast time-resolved infrared spectroscopy. The absolute rate constants for their reaction with n-butylacrylate, thiophenol, bromotrichloromethane and oxygen were measured in acetonitrile solution. The rate constants of benzoyl radical addition to n-butylacrylate range from 1.3 x 10(5) to 5.5 x 10(5) M(-1) s(-1) and are about 2 orders of magnitude lower than for the n-butylacrylate addition to the counterradicals that are produced by alpha-cleavage of the investigated ketones. Density functional theoretical calculations have been performed in order to rationalize the observed reactivities of the initiating radicals. Calculations of the phosphorus-centered radicals generated by photolysis of an acyl and bis(acyl)phosphine oxide suggest that P atom Mulliken spin populations are an indicator of the relative reactivities of the phosphorus-centered radicals. The alpha-cleavage of (2,4,6-trimethylbenzoyl)phosphine oxide was studied by picosecond pump-probe and nanosecond step-scan time-resolved infrared spectroscopy. The results support a mechanism in which the alpha-cleavage occurs from the triplet excited state that has a lifetime less than or equal to the singlet excited state.

  14. Progress toward hydrogen peroxide micropulsion

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J C; Dittman, M D; Ledebuhr, A G

    1999-07-08

    A new self-pressurizing propulsion system has liquid thrusters and gas jet attitude control without heavy gas storage vessels. A pump boosts the pressure of a small fraction of the hydrogen peroxide, so that reacted propellant can controllably pressurize its own source tank. The warm decomposition gas also powers the pump and is supplied to the attitude control jets. The system has been incorporated into a prototype microsatellite for terrestrial maneuvering tests. Additional progress includes preliminary testing of a bipropellant thruster, and storage of unstabilized hydrogen peroxide in small sealed tanks.

  15. Synthesis and Crystal Structure of 2-Benzoyl Pyridine Thiosemicarbazato Palladium(Ⅱ)Chloride

    Institute of Scientific and Technical Information of China (English)

    刘泽华; 王守兴; 段春迎; 游效曾

    2001-01-01

    The title complex,2-benzoyl pyridine thiosemicarbazato palladium(Ⅱ)chloride [C13H11N4SPdCl,Mr=379.17],crystallizes in monoclinic,space group C2/c with a=12.1061(5),b=21.877(3),c=11.4832(6)A,β=108.29(9)°,V=2887.7(4)A3,Z=8,Dc=1.827g/cm3; μ=1.608cm-1 and F(000)=1568.R=0.0281 and wR=0.0684 for 1446 reflections with I > 2σ(Ⅰ).X-ray crystal structure analysis revealed that the coordination geometry of Pd atom is a distorted square plane with two Pd- N bonds,one Pd - S bond and one Pd - Cl bond.The Schiff-base ligand loses a proton from its tautomeric thiol form and coordinates to the Pd atom via the mercapto sulfur and theβ-nitrogen atoms.

  16. N-benzoyl-n-phenylhydroxylamine impregnated Amberlite XAD-4 beads for selective removal of thorium.

    Science.gov (United States)

    Chandramouleeswaran, S; Ramkumar, Jayshree

    2014-09-15

    n-Benzoyl-n-phenylhydroxylamine impregnated Amberlite XAD-4 beads were used for the removal of Th(IV) from a mixture of ions. The impregnated XAD was characterized using different techniques like weight and colour change, IR spectra, surface area and pore size measurements to confirm the presence of n-BPHA within the macroreticular resin structure. The experimental conditions were optimized to make the separation fast and selective. It was seen that the maximum sorption was achieved in the pH range of 3-7.5 and uptake was nearly complete within half an hour. The results obtained in the present study were subjected to extensive modelling in order to get a complete understanding of the sorption process. It is seen that the maximum uptake was calculated to be 500 mg/g and has very fast kinetics it was seen that the process is chemisorption. It was further deduced from the modelling that the overall sorption process was controlled dominantly by external mass transfer. Considering the simplicity this procedure, the present study has a possible application for the removal of thorium from different mixtures.

  17. Hybrid molecules of carvacrol and benzoyl urea/thiourea with potential applications in agriculture and medicine.

    Science.gov (United States)

    Pete, Umesh D; Zade, Chetan M; Bhosale, Jitendra D; Tupe, Santosh G; Chaudhary, Preeti M; Dikundwar, Amol G; Bendre, Ratnamala S

    2012-09-01

    Benzoyl phenyl urea, a class of insect growth regulator's acts by inhibiting chitin synthesis. Carvacrol, a naturally occurring monoterpenoid is an effective antifungal agent. We have structurally modified carvacrol (2-methyl-5-[1-methylethyl] phenol) by introducing benzoylphenyl urea linkage. Two series of benzoylcarvacryl thiourea (BCTU, 4a-f) and benzoylcarvacryl urea (BCU, 5a-f) derivatives were prepared and characterized by elemental analysis, IR, (1)H and (13)C NMR and Mass spectroscopy. Derivatives 4b, 4d, 4e, 4f and 5d, 5f showed comparable insecticidal activity with the standard BPU lufenuron against Dysdercus koenigii. BCTU derivatives 4c, 4e and BCU 5c showed good antifungal activity against phytopathogenic fungi viz. Magnaporthe grisae, Fusarium oxysporum, Dreschlera oryzae; food spoilage yeasts viz. Debaromyces hansenii, Pichia membranifaciens; and human pathogens viz. Candida albicans and Cryptococcus neoformans. Compounds 5d, 5e and 5f showed potent activity against human pathogens. Moderate and selective activity was observed for other compounds. All the synthesized compounds were non-haemolytic. These compounds have potential application in agriculture and medicine.

  18. Safety in the Chemical Laboratory. Organic Peroxides.

    Science.gov (United States)

    Shanley, Edward S.

    1990-01-01

    Discussed is the thermodynamic instability of organic peroxides. The process of autoxidation which results in peroxide formation is described. Precautions necessary to prevent autoxidation hazards associated with these reagents are suggested. (CW)

  19. Determination of Benzoyl Peroxide in Wheat Flour Using Colorimetric Method%面粉中过氧化苯甲酰的比色测定方法

    Institute of Scientific and Technical Information of China (English)

    刘荣琴; 高磊红; 李荣芬

    2013-01-01

    利用过氧化苯甲酰(BPO)的氧化还原性质,提出了对面粉中的BPO进行测定的简易方法.采用乙醇为提取剂对面粉中BPO进行提取;使用KI为还原剂与BPO进行反应,生成的I2与淀粉指示剂反应生成蓝紫色络合物,通过比较颜色的深浅,对面粉中的BPO进行定性和半定量测定.方法的检出限为0.008 g/kg.

  20. 21 CFR 582.1366 - Hydrogen peroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  1. Inhibition of gap junctional intercellular communication and activation of mitogen-activated protein kinase by tumor-promoting organic peroxides and protection by resveratrol.

    Science.gov (United States)

    Upham, Brad L; Guzvić, Miodrag; Scott, Jacob; Carbone, Joseph M; Blaha, Ludek; Coe, Chad; Li, Lan Lan; Rummel, Alisa M; Trosko, James E

    2007-01-01

    Dicumyl peroxide (di-CuOOH) and benzoyl peroxide (BzOOH) act as tumor promoters in SENCAR mice, whereas di-tert-butylhydroperoxide does not. Tumor promotion requires the removal of growth suppression by inhibition of gap junctional intercellular communication (GJIC) and the induction of mitogenic intracellular pathways. We showed that di-CuOOH and BzOOH both reversibly inhibited GJIC and transiently activated mitogen-activated protein kinase, specifically, the extracellular receptor kinase at noncytotoxic conditions in WB-F344 rat liver epithelial cells, whereas the non-tumor-promoting di-tert-butylhydroperoxide did not inhibit GJIC or activate extracellular receptor kinase. di-CuOOH but not BzOOH inhibited GJIC through a phosphatidylcholine-specific phospholipase C-dependent mechanism. N-acetylcysteine (NAC) was needed to prevent a cytotoxic, glutathione-depleting effect of BzOOH, whereas di-CuOOH was noncytotoxic and did not alter glutathione levels at all doses and times tested. Pretreatment of WB-F344 cells with resveratrol, a polyphenolic antioxidant present in red wine, prevented at physiological doses the inhibition of GJIC by di-CuOOH but not from BzOOH and was effective in significantly preventing extracellular receptor kinase activation by both peroxides. NAC did not prevent any of the peroxide effects on either GJIC or extracellular receptor kinase, suggesting a specific antioxidant effect of resveratrol.

  2. Peroxide-induced cell death and lipid peroxidation in C6 glioma cells.

    Science.gov (United States)

    Linden, Arne; Gülden, Michael; Martin, Hans-Jörg; Maser, Edmund; Seibert, Hasso

    2008-08-01

    Peroxides are often used as models to induce oxidative damage in cells in vitro. The aim of the present study was to elucidate the role of lipid peroxidation in peroxide-induced cell death. To this end (i) the ability to induce lipid peroxidation in C6 rat astroglioma cells of hydrogen peroxide (H2O2), cumene hydroperoxide (CHP) and t-butyl hydroperoxide (t-BuOOH) (ii) the relation between peroxide-induced lipid peroxidation and cell death in terms of time and concentration dependency and (iii) the capability of the lipid peroxidation chain breaking alpha-tocopherol to prevent peroxide-induced lipid peroxidation and/or cell death were investigated. Lipid peroxidation was characterised by measuring thiobarbituric acid reactive substances (TBARS) and, by HPLC, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE) and hexanal. Within 2 h CHP, t-BuOOH and H2O2 induced cell death with EC50 values of 59+/-9 microM, 290+/-30 microM and 12+/-1.1 mM, respectively. CHP and t-BuOOH, but not H2O2 induced lipid peroxidation in C6 cells with EC50 values of 15+/-14 microM and 130+/-33 microM, respectively. The TBARS measured almost exclusively consisted of MDA. 4-HNE was mostly not detectable. The concentration of hexanal slightly increased with increasing concentrations of organic peroxides. Regarding time and concentration dependency lipid peroxidation preceded cell death. Pretreatment with alpha-tocopherol (10 microM, 24 h) prevented both, peroxide-induced lipid peroxidation and cell death. The results strongly indicate a major role of lipid peroxidation in the killing of C6 cells by organic peroxides but also that lipid peroxidation is not involved in H2O2 induced cell death.

  3. Structures of N- (2,3,4,6-Tetra- O-acetyl-β- D-glycosyl) thiocar-bamic Benzoyl Hydrazine

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Shu-Sheng(张书圣); LIN,Jie-Hua(林洁华); JIAN,Fang-Fang(建方方); JIAO,Kui(焦奎)

    2002-01-01

    The crystal structure of N-( 2, 3 , 4 , 6-tetra-O-acetyl- β- D-glycosyl)-thiocarbamic benzoyl hydrazine ( C22 H27 N3O9S) was determined by X-ray diffraction method. The hexopyranosyl ring adopts a chair conformation. All the ring substituents are in the equatorial positions. The acetoxyl-methyl group is in synclinal conformation. The S atom is in synperiplanar conformation while the benzoyl hydrazine moiety is anti-periplanar. The thiocarbamic moiety is almost coplanar with the benzoyl hydrazine group. There are two intramolecular hydrogen bonds and one intermolecular hydrogen bond for each molecule in the crystal structure. The molecules form a network structure through intermolecular hydrogen bonds.

  4. Synthesis, physico-chemical characterization and biological activity of copper(ii and nickel(ii complexes with l-benzoyl-2-methylbenzimidazole derivatives

    Directory of Open Access Journals (Sweden)

    Podunavac-Kuzmanović Sanja O.

    2002-01-01

    Full Text Available Chlorides of copper(II and nickel(ll react with 1-benzoyl-2-methylbenzimidazole or 1-(4-chlorobenzoyl-2-methylbenzimidazole to give complexes of the type [M(LnCln(H20∙Cln (M = Cu or Ni; L = (1-benzoyl-2-methylbenzimidazole or 1-(4-chlorobenzoyl-2-methylbenzimidazole; n=O, 1 or 2. The complexes were synthesized and characterized by elemental analysis, molar conductivity magnetic susceptibility measurements and IR spectra. These studies suggest that all the complexes possess an octahedral stereochemistry. The antibacterial activity of (1-benzoyl-2-methylbenzimidazole or 1-(4-chlorobenzoyl-2-methylbenzimidazole and their complexes was evaluated against Escherichia coli and Bacillus sp.

  5. Nitric oxide inhibitory activity and antioxidant evaluations of 2-benzoyl-6-benzylidenecyclohexanone analogs, a novel series of curcuminoid and diarylpentanoid derivatives.

    Science.gov (United States)

    Leong, Sze Wei; Mohd Faudzi, Siti Munirah; Abas, Faridah; Mohd Aluwi, Mohd Fadhlizil Fasihi; Rullah, Kamal; Lam, Kok Wai; Abdul Bahari, Mohd Nazri; Ahmad, Syahida; Tham, Chau Ling; Shaari, Khozirah; Lajis, Nordin H

    2015-08-15

    A series of twenty-four 2-benzoyl-6-benzylidenecyclohexanone analogs were synthesized and evaluated for their nitric oxide inhibition and antioxidant activity. Six compounds (3, 8, 10, 17, 18 and 19) were found to exhibit significant NO inhibitory activity in LPS/IFN-induced RAW 264.7 macrophages, of which compound 10 demonstrated the highest activity with the IC50 value of 4.2 ± 0.2 μM. Furthermore, two compounds (10 and 17) displayed antioxidant activity upon both the DPPH scavenging and FRAP analyses. However, none of the 2-benzoyl-6-benzylidenecyclohexanone analogs significantly scavenged NO radical. Structure-activity comparison suggested that 3,4-dihydroxylphenyl ring is crucial for bioactivities of the 2-benzoyl-6-benzylidenecyclohexanone analogs. The results from this study and the reports from previous studies indicated that compound 10 could be a candidate for further investigation on its potential as a new anti-inflammatory agent.

  6. Extraction of trace thorium from hydrochloric acid media by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

    Institute of Scientific and Technical Information of China (English)

    YANG Wei-Fan; YUAN Shuang-Gui; XU Yan-Bing; XIAO Yong-Hou; XIONG Bing

    2003-01-01

    The paper describes the solvent extraction of trace thorium from hydrochloric acid media by1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) using a radioactive tracer technique. The percent extraction ofthorium was studied as a function of acidity, PMBP concentration and equilibrium time. The back-extraction behaviorof thorium from the organic phase was also tested. Separation of thorium was performed from fission products pro-duced in 14 MeV neutron bombardment of natural uranium by employing the PMBP extraction procedure. Thegamma-ray spectra of the separated thorium fractions show that thorium can be separated from most of fission prod-ucts and a large amount of uranium.

  7. Synthesis, Characterization, and Biological Activity of Some Transition Metal Complexes of N-Benzoyl-N′-2-thiophenethiocarbohydrazide

    Directory of Open Access Journals (Sweden)

    Mahendra Yadav

    2012-01-01

    Full Text Available In the present study, Mn(II, Fe(II, Ni(II, and Cu(II complexes of N-benzoyl -N′-2-thiophenethiocarbohydrazide (H2 BTTH have been synthesized and characterized by elemental analysis, magnetic susceptibility measurements, infrared, NMR, electronic, and ESR spectral studies. The complexes were found to have compositions [Mn(H BTTH2], [Ni(BTTH(H2O2], [Cu(BTTH], and [Fe(H BTTH2EtOH]. The antibacterial and antifungal properties of H2 BTTH and its metal complexes have been screened against several bacteria and fungi.

  8. Structure and Biological Activities of 3-Phenyl-2-[1-benzoyl-1-(1,2,4-triazol-1-yl)] Methenyl Thiazolidine

    Institute of Scientific and Technical Information of China (English)

    XU Liang-zhong; JIAN Fang-fang; QIN Yong-qi; YU Guan-ping; JIAO Kui

    2004-01-01

    The title compound 3-phenyl-2-[1-benzoyl-1-(1,2,4-triazol-1-yl)]methenyl thiazolidine was synthesized from acetophenone, triazole, phenylthioisocyanate and 1,2-dibromo-ethane by several step reactions. Its structure was identified by means of 1H NMR, MS and IR spectrometries. The single crystal structure of 3-phenyl-2-[1-benzoyl-1-(1,2,4-triazol-1-yl)]methenyl thiazolidine was determined by X-ray diffraction. The preliminary bioassays have shown that the title compound exhibits the weak activities of fungicide and plant growth regulator.

  9. Stereochemistry of N-Benzoyl-5-substituted-1-benzazepines Revisited: Synthesis of the Conformationally Biased Derivatives and Revision of the Reported Structure.

    Science.gov (United States)

    Tabata, Hidetsugu; Yoneda, Tetsuya; Tasaka, Tomohiko; Ito, Shigekazu; Oshitari, Tetsuta; Takahashi, Hideyo; Natsugari, Hideaki

    2016-04-15

    The syn (aR*,5R*) and anti (aS*,5R*) diastereomers of N-benzoyl-C5-substituted-1-benzazepines originating in the chiralities at C5 and the Ar-N(C═O) axis were first stereoselectively synthesized by biasing the conformation with a substituent at C6 and C9, respectively. Detailed examination of the stereochemistry (i.e., conformation and configuration) of these N-benzoyl-1-benzazepines by X-ray crystallographic analysis, VT NMR, and DFT calculations revealed new physicochemical aspects of these heterocycles including revision of the stereochemistry previously reported.

  10. Decomposition kinetics and thermal hazard of organic peroxides%有机过氧化物分解机理及热危害

    Institute of Scientific and Technical Information of China (English)

    孙峰; 薛岩; 谢传欣; 金满平; 黄飞

    2012-01-01

    The thermal hazard of organic peroxides should be assessed to predict and avoid runaway decomposition. In this paper, the Setaram C80 was used to investigate thermal decomposition of several organic peroxides such as cumene hydroperoxide (CHP), tert-butyl hydroperoxide (TBHP), dicumyl peroxide (DCP), di-tert-buty\\ peroxide (DTBP), benzoyl peroxide (BPO), tert-butyl peroxybenzoate ( TBPB ) , methyl ethyl ketone peroxide ( MEKP ) , 2 , 5-dimethyl-2 , 5-di (tert-butylperoxy ) hexane (DHBP) and 1, 1-di-(tert-butylperoxy)-3, 3, 5-trimethylcyclohexane (TMCH). Decomposition heat of the organic peroxides was calculated from isothermal scanning curves. The nth-order or autocatalytic reaction kinetics model was established for these organic peroxides, and self accelerating decomposition temperature (SADT) was derived by using Semenov model. The results showed that decomposition of the organic peroxides mostly followed nth-order model with approximate reaction order of 1, however, some of them preferred to autocatalytic model. The SADT of the organic peroxides calculated was in good agreement with values from literatures, demonstrating reaction kinetics fitting and SADT calculating in this paper are of scientific.%为了预防及控制有机过氧化物的分解爆炸事故,需要对其热危害进行必要的评估.利用塞塔姆C80微量热仪对不同种类的9种有机过氧化物进行热扫描测试,并分别利用n级反应模型及自催化反应模型对扫描曲线进行拟合,准确得到了这些物质的分解热及分解机理.根据反应动力学数据,采用Semenov爆炸模型及联合国H.3-等温储存试验原理,得到了9种有机过氧化物的临界温度及自加速分解温度(SADT).结果表明,大部分有机过氧化物分解遵循n级反应模型,反应级数在1左右,少部分有机过氧化物分解时有一定的自催化效应.所得的SADT数据与文献值符合较好,证明本文动力学模拟及SADT计算方法的科学性.

  11. Peroxides and peroxide-degrading enzymes in the thyroid.

    Science.gov (United States)

    Schweizer, Ulrich; Chiu, Jazmin; Köhrle, Josef

    2008-09-01

    Iodination of thyroglobulin is the key step of thyroid hormone biosynthesis. It is catalyzed by thyroid peroxidase and occurs within the follicular space at the apical plasma membrane. Hydrogen peroxide produced by thyrocytes as an oxidant for iodide may compromise cellular and genomic integrity of the surrounding cells, unless these are sufficiently protected by peroxidases. Thus, peroxidases play two opposing roles in thyroid biology. Both aspects of peroxide biology in the thyroid are separated in space and time and respond to the different physiological states of the thyrocytes. Redox-protective peroxidases in the thyroid are peroxiredoxins, glutathione peroxidases, and catalase. Glutathione peroxidases are selenoenzymes, whereas selenium-independent peroxiredoxins are functionally linked to the selenoenzymes of the thioredoxin reductase family through their thioredoxin cofactors. Thus, selenium impacts directly and indirectly on protective enzymes in the thyroid, a link that has been supported by animal experiments and clinical observations. In view of this relationship, it is remarkable that rather little is known about selenoprotein expression and their potential functional roles in the thyroid. Moreover, selenium-dependent and -independent peroxidases have rarely been examined in the same studies. Therefore, we review the relevant literature and present expression data of both selenium-dependent and -independent peroxidases in the murine thyroid.

  12. Substitution Effects and Linear Free Energy Relationships During Reduction of 4- Benzoyl-n-(4-substituted Benzyl)pyridinium Cations

    Science.gov (United States)

    Leventis, Nicholas; Zhang, Guo-Hui; Rawashdeh, Abdel-Monem M.; Sotiriou-Leventis, Chariklia; Gray, Hugh R. (Technical Monitor)

    2003-01-01

    In analogy to 4-(para-substituted benzoyl)-N-methylpyridinium cations (1-X's), the title species (2-X's, -X = -OCH3, -CH3, -H, -Br, -COCH3, -NO2) undergo two reversible, well-separated (E(sub 1/2) greater than or equal to 650 mV) one-electron reductions. The effect of substitution on the reduction potentials of 2-X's is much weaker than the effect of the same substituents on 1-X's: the Hammett rho-values are 0.80 and 0.93 for the 1st- and 2nd-e reduction of 2-X's vs. 2.3 and 3.3 for the same reductions of 1-X's, respectively. Importantly, the nitro group of 2-NO2 undergoes reduction before the 2nd-e reduction of the 4-benzoylpyridinium system. These results suggest that the redox potentials of the 4-benzoylpyridinium system can be course-tuned via p-benzoyl substitution and fine-tuned via para-benzyl substitution. Introducing the recently derived substituent constant of the -NO2(sup)- group (sigma para-NO2(sup)- = -0.97) yields an excellent correlation for the 3rd-e reduction of 2- NO2 (corresponding to the reduction of the carbonyl group) with the 2nd-e reduction of the other 2-X's, and confirms the electron donating properties of -NO2(sup)-.

  13. A New Benzoyl Compound Isolated from the Endophytic Fungi of Kandis Gajah (Garcinia griffithii and Asam Kandis (Garcinia cowa

    Directory of Open Access Journals (Sweden)

    Elfita Elfita

    2016-12-01

    Full Text Available Garcinia griffithii and Garcinia cowa belong to the genus Garcinia. The genus Garcinia has been known to be a rich source of secondary metabolites, such as xanthones, benzophenones, flavonoids, steroids, terpenoids, and other phenolic derivatives. Previous investigations of endophytic fungi from G. griffithii revealed the presence of three compounds not found in the host. In order to the continue the phytochemical work on endophytic fungi of G. griffithii, the constituent of the endophytic fungi of G. griffithii was re-examined. In this study, a benzoyl compound similar to that found in the endophytic fungus of G. cowa was observed. The same benzoyl compound was also isolated from the endophytic fungus Acremonium sp of G. griffithii and Aspergillus sp of G. cowa with cultivation of eight weeks in static conditions at room temperature. The culture medium was partitioned using ethyl acetate and evaporated to obtain the concentrated extract. Isolation of compounds was performed using the chromatography method. The chemical structure was proposed on the basis of spectroscopic data, including ultraviolet (UV, infrared (IR, mass spectrometry (MS, proton nuclear magnetic resonance (1H-NMR, carbon nuclear magnetic resonance (13C-NMR, heteronuclear single-quantum correlation spectroscopy (HSQC, heteronuclear multiple-bond correlation spectroscopy (HMBC, and correlation spectroscopy (COSY.

  14. Synthesis, Structure and Noncovalent Interactions of Palladium(Ⅱ) Complexes with N-Benzoyl-β-phenylalaninate Dianion and Aromatic Diimine

    Institute of Scientific and Technical Information of China (English)

    CHEN,Yao-Feng(陈耀峰); GONG,Yu-Qiu(龚钰秋); ZHANG,Hua-Song(张华松)

    2002-01-01

    Two palladiun(Ⅱ) complexes, [Pd(bipy)(BzPhe-N,O) ] and [Pd(phen) (BzPhe-N,O) ] @4H2O were synthesized by reactions between Pd(bipy)Cl2 and BzPheH2 ( N-benzoyl- β-phenylalanine), Pd(phen) Cla and BzPheH2 in water at pH ~ 9, with their structrues determined by X-ray diffraction analysis. The Pd atom is coordinated by two nitrogen atoms of bipy (or phen), the deprotonated amido type nitrogen atom and one of the carboxylic oxygens of BzPhe (BzPhe = N-benzoyl-β-phenylalaninate dianion). In the complex [Pd(phen)(BzPhe-N,O)]@ 4H2O, the side chain of phenvlalanine is located above and approximately parallels to the coordination plane. Both the aromic-aromatic stacking interaction between the phenyl ring of phenylalanine and phen, and the metal ion-aromatic interaction between the phenyi ring of phenylalanine and Pd(Ⅱ) were observed. [Pd(bipy)(BzPhe-N,O) ] has the phenylalanyl side chain oriented outwards from the coordination plane, which is mainly due to the interaction between the carbonyl oxygen atom of the amido group and the phenyl ring of phenylalanine. The reason for the different orientation of phenylalanyl side chain in the complexes was suggested.

  15. Vibrational and quantum chemical investigation of cyclization of thiosemicarbazide group in 1-benzoyl-4-phenyl-3-thiosemicarbazide.

    Science.gov (United States)

    Gautam, Priyanka; Prakash, Om; Dani, R K; Singh, N K; Singh, Ranjan K

    2014-11-11

    1-Benzoyl-4-phenyl-3-thiosemicarbazide (H3bpt) was treated with acid - base in one sequence and base - acid in other sequence, both of which lead to ring formation of thiosemicarbazide group, giving N-phenyl-5-phenyl-1,3,4-thiadiazol-2-amine (Hppta) in the first case and 4,5-diphenyl-2,4-dihydro-1,2,4-triazole-3-thione (Hdptt) in the second case. The primary (H3bpt) as well as the resulting compounds (Hppta & Hdptt) has been characterized by elemental analyses, NMR, FTIR and Raman spectroscopic techniques. The quantum chemical calculations of the compounds are performed using DFT/B3LYP/6311G(d,p) method for geometry optimizations and also for prediction of the molecular properties. The cyclization is confirmed by disappearance of many bands belonging to the open chain subgroups of H3bpt such as; NH stretching, NH bending, CN stretching, NH puckering, CO stretching etc. The ring formation of 1-benzoyl-4-phenyl-3-thiosemicarbazide (H3bpt) has been further confirmed by the appearance of many bands belonging to the closed ring of thiosemicarbazide in the resulting compounds Hppta and Hdptt.

  16. Synthesis and Biological Activity of Novel Amino Acid-(N'-Benzoyl Hydrazide and Amino Acid-(N'-Nicotinoyl Hydrazide Derivatives

    Directory of Open Access Journals (Sweden)

    Sherine N. Khattab

    2005-09-01

    Full Text Available The coupling reaction of benzoic acid and nicotinic acid hydrazides with N- protected L-amino acids including valine, leucine, phenylalanine, glutamic acid and tyrosine is reported. The target compounds, N-Boc-amino acid-(N`-benzoyl- and N- Boc-amino acid-(N`-nicotinoyl hydrazides 5a-5e and 6a-6e were prepared in very high yields and purity using N-[(dimethylamino-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl- methylene]-N-methyl-methanaminium hexafluorophosphate N-oxide (HATU as coupling reagent. The antimicrobial activity of the Cu and Cd complexes of the designed compounds was tested. The products were deprotected affording the corresponding amino acid-(N`-benzoyl hydrazide hydrochloride salts (7a-7e and amino acid-(N`- nicotinoyl hydrazide hydrochloride salts (8a-8e. These compounds and their Cu and Cd complexes were also tested for their antimicrobial activity. Several compounds showed comparable activity to that of ampicillin against S. aureus and E. coli.

  17. Coating for components requiring hydrogen peroxide compatibility

    Science.gov (United States)

    Yousefiani, Ali (Inventor)

    2010-01-01

    The present invention provides a heretofore-unknown use for zirconium nitride as a hydrogen peroxide compatible protective coating that was discovered to be useful to protect components that catalyze the decomposition of hydrogen peroxide or corrode when exposed to hydrogen peroxide. A zirconium nitride coating of the invention may be applied to a variety of substrates (e.g., metals) using art-recognized techniques, such as plasma vapor deposition. The present invention further provides components and articles of manufacture having hydrogen peroxide compatibility, particularly components for use in aerospace and industrial manufacturing applications. The zirconium nitride barrier coating of the invention provides protection from corrosion by reaction with hydrogen peroxide, as well as prevention of hydrogen peroxide decomposition.

  18. Hydrogen peroxide enteritis: the "snow white" sign.

    Science.gov (United States)

    Bilotta, J J; Waye, J D

    1989-01-01

    Hydrogen peroxide is a useful disinfectant that has achieved widespread utility in varied clinical settings. We report an epidemic of hydrogen peroxide enteritis that developed in seven patients in our gastrointestinal endoscopy unit during a 2-week period in early 1988. During endoscopy, using recently sterilized endoscopes that were flushed with 3% hydrogen peroxide after the glutaraldehyde cycle, instantaneous blanching (the "snow white" sign) and effervescence were noted on the mucosal surfaces when the water button was depressed. No patient subsequently suffered morbidity or mortality associated with this peroxide enteritis, and the biopsy specimens revealed nonspecific inflammation. The toxicity of hydrogen peroxide when used in enema form is reviewed, as well as the pathogenesis of peroxide enteritis.

  19. PEROXIDE PROCESS FOR SEPARATION OF RADIOACTIVE MATERIALS

    Science.gov (United States)

    Seaborg, G.T.; Perlman, I.

    1958-09-16

    reduced state, from hexavalent uranium. It consists in treating an aqueous solution containing such uranium and plutonium ions with sulfate ions in order to form a soluble uranium sulfate complex and then treating the solution with a soluble thorium compound and a soluble peroxide compound in order to ferm a thorium peroxide carrier precipitate which carries down with it the plutonium peroxide present. During this treatment the pH of the solution must be maintained between 2 and 3.

  20. PEROXIDE BLEACHING OF LOW-FREENESS TMP

    Institute of Scientific and Technical Information of China (English)

    ZhongLiu; Y.Ni; Z.Li,G.Court

    2004-01-01

    Peroxide bleaching is an essential unit operation toproduce value-added mechanical pulp-based papergrade. In this paper, we presented the results fromperoxide bleaching of low-freeness TMP for theproduction of SC paper. Two aspects wereaddressed; the effect of pulp strength and theformation of anionic trashes. The strength properties,such as tensile, burst and zero-span tensile, areimproved after the peroxide bleaching process. Theamount of anionic trashes formed is almostproportional to the hydrogen peroxide charge.

  1. Hydrogen peroxide on the surface of Europa

    Science.gov (United States)

    Carlson, R.W.; Anderson, M.S.; Johnson, R.E.; Smythe, W.D.; Hendrix, A.R.; Barth, C.A.; Soderblom, L.A.; Hansen, G.B.; McCord, T.B.; Dalton, J.B.; Clark, R.N.; Shirley, J.H.; Ocampo, A.C.; Matson, D.L.

    1999-01-01

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

  2. PEROXIDE BLEACHING OF LOW-FREENESS TMP

    Institute of Scientific and Technical Information of China (English)

    Zhong Liu; Y. Ni; Z. Li; G. Court

    2004-01-01

    Peroxide bleaching is an essential unit operation to produce value-added mechanical pulp-based paper grade. In this paper, we presented the results from peroxide bleaching of low-freeness TMP for the production of SC paper. Two aspects were addressed; the effect of pulp strength and the formation of anionic trashes. The strength properties,such as tensile, burst and zero-span tensile, are improved after the peroxide bleaching process. The amount of anionic trashes formed is almost proportional to the hydrogen peroxide charge.

  3. Design and development of novel insect growth regulators: synthesis, characterization and effect of benzoyl thymyl thioureas and ureas on total haemocyte count of Dysdercus koenigii.

    Science.gov (United States)

    Zade, Chetan M; Pete, Umesh D; Patil, Smita S; Bhosale, Jitendra D; Hadole, Chakradhar D; Kadam, Meghraj S; Bendre, Ratnamala S

    2012-01-01

    Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by (1)H and (13)C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.

  4. Benzoylation of Ergosterol through Nucleophilic Acyl Substitution and Subsequent Formation of Ergosterol Benzoate Endoperoxide by Reaction with Singlet Oxygen Generated by Photosensitization

    Science.gov (United States)

    Roslaniec, Mary C.; Sanford, Elizabeth M.

    2011-01-01

    Reactive oxygen species such as singlet oxygen have been a major focus of research in medicine. The effect of singlet oxygen on sterols within biological membranes is becoming increasingly more important. Ergosterol, a vitamin D precursor, is one such sterol. The benzoylation of ergosterol and subsequent reaction with singlet oxygen to form an…

  5. [Nitric oxide and lipid peroxidation].

    Science.gov (United States)

    Cristol, J P; Maggi, M F; Guérin, M C; Torreilles, J; Descomps, B

    1995-01-01

    Nitric oxide (NO) is a free radical produced enzymatically in biological systems from the guanidino group of L-arginine. Its large spectrum of biological effects is achieved through chemical interactions with different targets including oxygen (O2), superoxide (O2o-) and other oxygen reactive species (ROS), transition metals and thiols. Superoxide anions and other ROS have been reported to react with NO to produce peroxynitrite anions that can decompose to form nitrogen dioxide (NO2) and hydroxyl radial (OHo). Thus, NO has been reported to have a dual effect on lipid peroxidation (prooxidant via the peroxynitrite or antioxydant via the chelation of ROS). In the present study we have investigated in different models the in vitro and in vivo action of NO on lipid peroxidation. Copper-induced LDL oxidation were used as an in vitro model. Human LDL (100 micrograms ApoB/ml) were incubated in oxygene-saturated PBS buffer in presence or absence of Cu2+ (2.5 microM) with increasing concentrations of NO donnors (sodium nitroprussiate or nitroso-glutathione). LDL oxidation was monitored continuously for conjugated diene formation (234 nm) and 4-hydroxynonenal (HNE) accumulation. Exogenous NO prevents in a dose dependent manner the progress of copper-induced oxidation. Ischaemia-reperfusion injury (I/R), characterized by an overproduction of ROS, is used as an in vivo model. Anaesthetized rats were submitted to 1 hour renal ischaemia following by 2 hours of reperfusion. Sham-operated rats (SOP) were used as control. Lipid peroxidation was evaluated by measuring the HNE accumulated in rats kidneys in presence or absence of L-arginine or D-arginine infusion. L-arginine, but not D-arginine, enhances HNE accumulation in I/R but not in SOP (< 0.050 pmol/g tissue in SOP versus 0.6 nmol/g tissue in I/R), showing that, in this experimental conditions, NO produced from L-arginine, enhances the toxicity of ROS. This study shows that the pro- or antioxydant effects of NO are different

  6. 7 CFR 58.431 - Hydrogen peroxide.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  7. [Advances in peroxide-based decontaminating technologies].

    Science.gov (United States)

    Xi, Hai-ling; Zhao, San-ping; Zhou, Wen

    2013-05-01

    With the boosting demand for eco-friendly decontaminants, great achievements in peroxide-based decontaminating technologies have been made in recent years. These technologies have been applied in countering chemical/biological terrorist attacks, dealing with chemical/biological disasters and destructing environmental pollutants. Recent research advances in alpha-nucleophilic/oxidative reaction mechanisms of peroxide-based decontamination against chemical warfare agents were reviewed, and some classical peroxide-based decontaminants such as aqueous decontaminating solution, decontaminating foam, decontaminating emulsions, decontaminating gels, decontaminating vapors, and some newly developed decontaminating media (e.g., peroxide-based self-decontaminating materials and heterogeneous nano-catalytic decontamination systems) were introduced. However, currently available peroxide-based decontaminants still have some deficiencies. For example, their decontamination efficiencies are not as high as those of chlorine-containing decontaminants, and some peroxide-based decontaminants show relatively poor effect against certain agents. More study on the mechanisms of peroxide-based decontaminants and the interfacial interactions in heterogeneous decontamination media is suggested. New catalysts, multifunctional surfactants, self-decontaminating materials and corrosion preventing technologies should be developed before peroxide-based decontaminants really become true "green" decontaminants.

  8. Simple, field portable colorimetric detection device for organic peroxides and hydrogen peroxide

    Science.gov (United States)

    Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie; Reynolds, John G.; Nunes, Peter; Shields, Sharon J.

    2010-11-09

    A simple and effective system for the colorimetric determination of organic peroxides and hydrogen peroxide. A peroxide pen utilizing a swipe material attached to a polyethylene tube contains two crushable vials. The two crushable vials contain a colorimetric reagent separated into dry ingredients and liquid ingredients. After swiping a suspected substance or surface the vials are broken, the reagent is mixed thoroughly and the reagent is allowed to wick into the swipe material. The presence of organic peroxides or hydrogen peroxide is confirmed by a deep blue color.

  9. Rearrangements of organic peroxides and related processes.

    Science.gov (United States)

    Yaremenko, Ivan A; Vil', Vera A; Demchuk, Dmitry V; Terent'ev, Alexander O

    2016-01-01

    This review is the first to collate and summarize main data on named and unnamed rearrangement reactions of peroxides. It should be noted, that in the chemistry of peroxides two types of processes are considered under the term rearrangements. These are conventional rearrangements occurring with the retention of the molecular weight and transformations of one of the peroxide moieties after O-O-bond cleavage. Detailed information about the Baeyer-Villiger, Criegee, Hock, Kornblum-DeLaMare, Dakin, Elbs, Schenck, Smith, Wieland, and Story reactions is given. Unnamed rearrangements of organic peroxides and related processes are also analyzed. The rearrangements and related processes of important natural and synthetic peroxides are discussed separately.

  10. Inorganic precursor peroxides for antifouling coatings

    DEFF Research Database (Denmark)

    Olsen, S.M.; Pedersen, L.T.; Hermann, M.H.

    2009-01-01

    Modern antifouling coatings are generally based on cuprous oxide (Cu2O) and organic biocides as active ingredients. Cu2O is prone to bioaccumulation, and should therefore be replaced by more environmentally benign compounds when technically possible. However, cuprous oxide does not only provide...... antifouling properties, it is also a vital ingredient for the antifouling coating to obtain its polishing and leaching mechanism. In this paper, peroxides of strontium, calcium, magnesium, and zinc are tested as pigments in antifouling coatings. The peroxides react with seawater to create hydrogen peroxide...... and highly seawater-soluble ions of the metal. The goals have been to establish the antifouling potency of an antifouling coating that releases hydrogen peroxide as biocide, and to investigate the potential use of peroxides as water-soluble polishing and leaching pigments. The investigations have shown...

  11. Rearrangements of organic peroxides and related processes

    Science.gov (United States)

    Yaremenko, Ivan A; Vil’, Vera A; Demchuk, Dmitry V

    2016-01-01

    Summary This review is the first to collate and summarize main data on named and unnamed rearrangement reactions of peroxides. It should be noted, that in the chemistry of peroxides two types of processes are considered under the term rearrangements. These are conventional rearrangements occurring with the retention of the molecular weight and transformations of one of the peroxide moieties after O–O-bond cleavage. Detailed information about the Baeyer−Villiger, Criegee, Hock, Kornblum−DeLaMare, Dakin, Elbs, Schenck, Smith, Wieland, and Story reactions is given. Unnamed rearrangements of organic peroxides and related processes are also analyzed. The rearrangements and related processes of important natural and synthetic peroxides are discussed separately. PMID:27559418

  12. Vapor Hydrogen Peroxide Sterilization Certification

    Science.gov (United States)

    Chen, Fei; Chung, Shirley; Barengoltz, Jack

    For interplanetary missions landing on a planet of potential biological interest, United States NASA planetary protection currently requires that the flight system must be assembled, tested and ultimately launched with the intent of minimizing the bioload taken to and deposited on the planet. Currently the only NASA approved microbial reduction method is dry heat sterilization process. However, with utilization of such elements as highly sophisticated electronics and sensors in modern spacecraft, this process presents significant materials challenges and is thus an undesirable bioburden reduction method to design engineers. The objective of this work is to introduce vapor hydrogen peroxide (VHP) as an alternative to dry heat microbial reduction to meet planetary protection requirements. The VHP sterilization technology is widely used by the medical industry, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal of our study is determine the minimum VHP process conditions for PP acceptable microbial reduction levels. A series of experiments were conducted using Geobacillus stearothermophilus to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters -hydrogen peroxide concentration, number of pulses, and exposure duration -the investigation also considered the possible effect of environmental pa-rameters. Temperature, relative humidity, and material substrate effects on lethality were also studied. Based on the results, a most conservative D value was recommended. This recom-mended D value was also validated using VHP "hardy" strains that were isolated from clean-rooms and environmental populations collected from spacecraft relevant areas. The efficiency of VHP at ambient condition as well as VHP material compatibility will also be

  13. MEASUREMENT AND MODELING OF THE DRY DEPOSITION OF PEROXIDES

    Science.gov (United States)

    Measurements of the dry deposition velocity (Vd) of hydrogen peroxide (H2O2) and total organic peroxides (ROOH) were made during four experiments at three forested sites. Details and uncertainties associated with the measurement of peroxide...

  14. Synthesis, characterization and applications of polymer-metal chelates derived from poly[((4-acryloxy acetophenone)-divinylbenzene)] benzoyl hydrazone resins

    Indian Academy of Sciences (India)

    Thammisetty Ravi Sankar; K Kesavulu; Peddakotla Venkata Ramana

    2014-05-01

    4-Acryloxy acetophenone was prepared and subjected to suspension polymerization with divinylbenzene as a cross-linking agent. The resulting network polymer was ligated with benzoyl hydrazone. The functional polymer was treated with metal ions [Cu(II), Fe(II)]. The polymer-metal complexes obtained were characterized by elemental analysis, IR, 1H-NMR, solid state 13C cross-polarization magic-angle spinning (CP/MAS) NMR, electron paramagnetic resonance (EPR), thermogravimetric and scanning electron microscopy (SEM) studies. The maximum uptake efficiency for the metal ions was determined. The reusability of the polymer ligand was tested and it was shown that even after four cycles, the efficiency of the uptake was not altered.

  15. Lipid peroxides level in the Indonesian elderly

    Directory of Open Access Journals (Sweden)

    Purwantyastuti Purwantyastuti

    2005-06-01

    Full Text Available A cross-sectional study was done to see the possible association of plasma lipid peroxides in the elderly with age and other factors. Plasma lipid peroxides is a product of free radical reactions which according to the latest theory of aging is the cause of aging process. Lipid peroxides were also found high in coronary heart disease. Four hundred forty relatively healthy elderly, age 55-85 years, were randomly chosen from free living elderly under guidance of health care centers (PUSKESMAS in Jakarta. Anamnesis and physical examination were done in the morning in the health centers. Blood samples were taken in fasting conditions, plasma lipids and lipid peroxides were measured according to standard methods. There was an age difference of lipid peroxides level in the elderly, which increased with age up to 70 years old. Elderly 70 years old and over had low plasma lipid peroxides. The level was not related to high plasma lipids. Higher level was found when more chronic degenerative diseases were found. (Med J Indones 2005; 14: 71-7Keywords: lipid peroxides, aging

  16. Titanium corrosion in alkaline hydrogen peroxide environments

    Science.gov (United States)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  17. High temperature decomposition of hydrogen peroxide

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  18. Membrane transport of hydrogen peroxide.

    Science.gov (United States)

    Bienert, Gerd P; Schjoerring, Jan K; Jahn, Thomas P

    2006-08-01

    Hydrogen peroxide (H2O2) belongs to the reactive oxygen species (ROS), known as oxidants that can react with various cellular targets thereby causing cell damage or even cell death. On the other hand, recent work has demonstrated that H2O2 also functions as a signalling molecule controlling different essential processes in plants and mammals. Because of these opposing functions the cellular level of H2O2 is likely to be subjected to tight regulation via processes involved in production, distribution and removal. Substantial progress has been made exploring the formation and scavenging of H2O2, whereas little is known about how this signal molecule is transported from its site of origin to the place of action or detoxification. From work in yeast and bacteria it is clear that the diffusion of H2O2 across membranes is limited. We have now obtained direct evidence that selected aquaporin homologues from plants and mammals have the capacity to channel H2O2 across membranes. The main focus of this review is (i) to summarize the most recent evidence for a signalling role of H2O2 in various pathways in plants and mammals and (ii) to discuss the relevance of specific transport of H2O2.

  19. Detection of interstellar hydrogen peroxide

    CERN Document Server

    Bergman, P; Liseau, R; Larsson, B; Olofsson, H; Menten, K M; Güsten, R

    2011-01-01

    The molecular species hydrogen peroxide, HOOH, is likely to be a key ingredient in the oxygen and water chemistry in the interstellar medium. Our aim with this investigation is to determine how abundant HOOH is in the cloud core {\\rho} Oph A. By observing several transitions of HOOH in the (sub)millimeter regime we seek to identify the molecule and also to determine the excitation conditions through a multilevel excitation analysis. We have detected three spectral lines toward the SM1 position of {\\rho} Oph A at velocity-corrected frequencies that coincide very closely with those measured from laboratory spectroscopy of HOOH. A fourth line was detected at the 4{\\sigma} level. We also found through mapping observations that the HOOH emission extends (about 0.05 pc) over the densest part of the {\\rho} Oph A cloud core. We derive an abundance of HOOH relative to that of H_2 in the SM1 core of about 1\\times10^(-10). To our knowledge, this is the first reported detection of HOOH in the interstellar medium.

  20. 49 CFR 173.225 - Packaging requirements and other provisions for organic peroxides.

    Science.gov (United States)

    2010-10-01

    ... Cyclohexanone peroxide(s) UN3104 ≤91 ≥9 OP6 13 Cyclohexanone peroxide(s) UN3105 ≤72 ≥28 OP7 5 Cyclohexanone peroxide(s) [as a paste] UN3106 ≤72 OP7 5, 21 Cyclohexanone peroxide(s) Exempt ≤32 >68 Exempt 29...

  1. Lipid peroxidation in experimental uveitis: sequential studies.

    Science.gov (United States)

    Goto, H; Wu, G S; Chen, F; Kristeva, M; Sevanian, A; Rao, N A

    1992-06-01

    Previously we have detected the occurrence of retinal lipid peroxidation initiated by phagocyte-derived oxygen radicals in experimental autoimmune uveitis (EAU). In the current studies, the confirmation of inflammation-mediated lipid peroxidation was proceeded further to include measurement of multiple parameters, including conjugated dienes, ketodienes, thiobarbituric acid reactive substances and fluorescent chromolipids. The assay for myeloperoxidase, a measure for the number of polymorphonuclear leukocytes in the inflammatory sites was also carried out. The levels of all these parameters were followed through the course of EAU development. The sequential evaluation of histologic changes using both light and electron microscopy was also carried out and the results were correlated with lipid peroxidation indices. These data suggest that the retinal lipid peroxidation plays a causative role in the subsequent retinal degeneration.

  2. Isothermal Decomposition of Hydrogen Peroxide Dihydrate

    Science.gov (United States)

    Loeffler, M. J.; Baragiola, R. A.

    2011-01-01

    We present a new method of growing pure solid hydrogen peroxide in an ultra high vacuum environment and apply it to determine thermal stability of the dihydrate compound that forms when water and hydrogen peroxide are mixed at low temperatures. Using infrared spectroscopy and thermogravimetric analysis, we quantified the isothermal decomposition of the metastable dihydrate at 151.6 K. This decomposition occurs by fractional distillation through the preferential sublimation of water, which leads to the formation of pure hydrogen peroxide. The results imply that in an astronomical environment where condensed mixtures of H2O2 and H2O are shielded from radiolytic decomposition and warmed to temperatures where sublimation is significant, highly concentrated or even pure hydrogen peroxide may form.

  3. Ultrafast Photoinduced Electron Transfer from Peroxide Dianion.

    Science.gov (United States)

    Anderson, Bryce L; Maher, Andrew G; Nava, Matthew; Lopez, Nazario; Cummins, Christopher C; Nocera, Daniel G

    2015-06-18

    The encapsulation of peroxide dianion by hexacarboxamide cryptand provides a platform for the study of electron transfer of isolated peroxide anion. Photoinitiated electron transfer (ET) between freely diffusing Ru(bpy)3(2+) and the peroxide dianion occurs with a rate constant of 2.0 × 10(10) M(-1) s(-1). A competing electron transfer quenching pathway is observed within an ion pair. Picosecond transient spectroscopy furnishes a rate constant of 1.1 × 10(10) s(-1) for this first-order process. A driving force dependence for the ET rate within the ion pair using a series of Ru(bpy)3(2+) derivatives allows for the electronic coupling and reorganization energies to be assessed. The ET reaction is nonadiabatic and dominated by a large inner-sphere reorganization energy, in accordance with that expected for the change in bond distance accompanying the conversion of peroxide dianion to superoxide anion.

  4. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell

    Science.gov (United States)

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D.

    2012-01-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells. PMID:23457415

  5. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell.

    Science.gov (United States)

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D

    2012-11-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells.

  6. EFFLUENT TREATMENT FACILITY PEROXIDE DESTRUCTION CATALYST TESTING

    Energy Technology Data Exchange (ETDEWEB)

    HALGREN DL

    2008-07-30

    The 200 Area Effluent Treatment Facility (ETF) main treatment train includes the peroxide destruction module (PDM) where the hydrogen peroxide residual from the upstream ultraviolet light/hydrogen peroxide oxidation unit is destroyed. Removal of the residual peroxide is necessary to protect downstream membranes from the strong oxidizer. The main component of the PDM is two reaction vessels utilizing granular activated carbon (GAC) as the reaction media. The PDM experienced a number of operability problems, including frequent plugging, and has not been utilized since the ETF changed to groundwater as the predominant feed. The unit seemed to be underperforming in regards to peroxide removal during the early periods of operation as well. It is anticipated that a functional PDM will be required for wastewater from the vitrification plant and other future streams. An alternate media or methodology needs to be identified to replace the GAC in the PDMs. This series of bench scale tests is to develop information to support an engineering study on the options for replacement of the existing GAC method for peroxide destruction at the ETF. A number of different catalysts will be compared as well as other potential methods such as strong reducing agents. The testing should lead to general conclusions on the viability of different catalysts and identify candidates for further study and evaluation.

  7. Cyclic Organic Peroxides Characterization by Mass Spectrometry and Raman Microscopy

    Science.gov (United States)

    2011-04-01

    organic peroxides,DART, hexa -methylene triperoxide diamine (HMTD), triacetonetriperoxide (TATP), TATP-d18, triacetone triperoxide (TATP), time-of...peroxides, DART, hexa -methylene triperoxide diamine (HMTD), triacetone triperoxide (TATP), , triacetone triperoxide (TATP), time-of-flight–mass...acetone tri-peroxide (TATP) and hexa -methylene triper- oxide diamine (HMTD) are the more commonly used cyclic organic peroxides in terrorist acts

  8. 糠醛苯甲酰腙的合成及生物活性研究%Synthesis and Bioactivities of Furfural Benzoyl Hydrazone

    Institute of Scientific and Technical Information of China (English)

    李水清; 赵春

    2011-01-01

    Furfural benzoyl hydrazone was synthesized using furfural, methyl benzoate and hydrazine hydrate as and its chemical structure was confirmed by elemental analysis and infrared spectrum. The bioactivities of furfural benzoyl hydrazone a-gainst Pieris rapae larvae was also tested in lab. The results showed that furfural benzoyl hydrazone had strong contact toxici-ty, stomach toxicity and weak antifeeding activity.%以糠醛、苯甲酸甲酯、水合肼为原料,合成了糠醛苯甲酰腙.经元素分析、红外光谱对目标化合物进行了结构表征.研究了糠醛苯甲酰腙对菜粉蝶(Pieris rapae L.)的生物活性,结果表明,糠醛苯甲酰腙对菜粉蝶具有较强的触杀活性和胃毒活性,而拒食作用较弱.

  9. Safe handling of potential peroxide forming compounds and their corresponding peroxide yielded derivatives.

    Energy Technology Data Exchange (ETDEWEB)

    Sears, Jeremiah Matthew; Boyle, Timothy J.; Dean, Christopher J.

    2013-06-01

    This report addresses recent developments concerning the identification and handling of potential peroxide forming (PPF) and peroxide yielded derivative (PYD) chemicals. PPF chemicals are described in terms of labeling, shelf lives, and safe handling requirements as required at SNL. The general peroxide chemistry concerning formation, prevention, and identification is cursorily presented to give some perspective to the generation of peroxides. The procedure for determining peroxide concentrations and the proper disposal methods established by the Hazardous Waste Handling Facility are also provided. Techniques such as neutralization and dilution are provided for the safe handling of any PYD chemicals to allow for safe handling. The appendices are a collection of all available SNL documentation pertaining to PPF/PYD chemicals to serve as a single reference.

  10. Phytic Acid Inhibits Lipid Peroxidation In Vitro

    Directory of Open Access Journals (Sweden)

    Alicja Zajdel

    2013-01-01

    Full Text Available Phytic acid (PA has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II/ascorbate-induced peroxidation, as well as Fe(II/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II/ascorbate. The observed inhibitory effect of PA on Fe(II/ascorbate-induced lipid peroxidation was lower (10–20% compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II/ascorbate-induced peroxidation. In the absence of Fe(II/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products.

  11. Phytic acid inhibits lipid peroxidation in vitro.

    Science.gov (United States)

    Zajdel, Alicja; Wilczok, Adam; Węglarz, Ludmiła; Dzierżewicz, Zofia

    2013-01-01

    Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10-20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products.

  12. Electronic structure and bonding in crystalline peroxides

    Science.gov (United States)

    Königstein, Markus; Sokol, Alexei A.; Catlow, C. Richard A.

    1999-08-01

    Hartree-Fock and density-functional PW91 theories as realized in the CRYSTAL95 code have been applied to investigate the structural and electronic properties of Ba, Sr, and Ca peroxide materials with the calcium carbide crystal structure, results for which are compared with those for the corresponding oxides. Special attention is paid to the stabilization of the peroxide molecular ion O2-2 in the ionic environment provided by the lattice, and to chemical bonding effects. In order to describe the covalent bonding within the O2-2 ion and the polarization of the O- ion in the crystal electrostatic field, it is essential to include an account of the effects of electron correlation. The PW91 density functional has allowed us to reproduce the crystallographic parameters within a 3% error. The chemical bonding within the peroxide molecular ion has a complex nature with a balance between the weak covalent bond of σz type and the strong electrostatic repulsion of the closed-shell electron groups occupying O 2s and O 2px and 2py states. Compression of the peroxide ion in the ionic crystals gives rise to an excessive overlap of the O 2s closed shells of the two O- ions of a peroxide molecular ion O2-2, which in turn determines the antibonding character of the interaction and chemical bonding in the O2-2 molecular ion.

  13. Protonation constant of salicylidene (N-benzoyl)glycyl hydrazone and its coordination behaviour towards some bivalent metal ions

    Indian Academy of Sciences (India)

    R K Lonibala; T R Rao; R K Babita Devia

    2006-07-01

    Protonation constant of an unsymmetrical Schiff base, salicylidene(N-benzoyl)glycyl hydrazone (SalBzGH), and formation constants of its complexes have been determined potentiometrically at different temperatures in aqueous dioxane medium. Complexes of SalBzGH with VO(IV), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) have been prepared. Elemental analyses, pH-metric, molar conductance, magnetic susceptibility, electronic, IR, ESR, XRD (powder) and NMR studies have been carried out to study the coordination behaviour of SalBzGH toward these metal ions. pH-metric and 1H NMR studies show the presence of two dissociable protons in the ligand. IR and NMR spectra suggest the tridentate nature of the ligand, coordinating as a uninegative species in the Mn(II) complex and as a dinegative species in all the other complexes. Presence of two different conformers of the ligand at room temperature and stabilization of a single conformer upon complex formation have been established from 1H NMR spectra of the metal-free ligand, Zn(II) and Hg(II) complexes recorded at 296 K. Electronic and ESR spectra indicate highly distorted tetragonal geometry for VO(IV) and Cu(II) complexes. XRD powder patterns of the Zn(II) complexes are indexed for an orthorhombic crystal system.

  14. Synthesis and Bioactivity of N-Benzoyl-N'-[5-(2'-substituted phenyl-2-furoyl] Semicarbazide Derivatives

    Directory of Open Access Journals (Sweden)

    Zining Cui

    2010-06-01

    Full Text Available In order to find novel chitin synthesis inhibitors (CSIs with good activity, benzoylphenylurea, a typical kind of CSIs, was chosen as the lead compound and 15 novel derivatives containing furan moieties were designed by converting the urea linkage of benzoylphenylureas into a semicarbazide and changing the aniline part into furoyl groups. The title compounds were synthesized by the reaction of substituted benzoyl isocyanates with 5-(substituted phenyl-2-furoyl hydrazine, and the structures were confirmed by IR, 1H-NMR, elemental analysis and single crystal X-ray diffraction analyses (compound E2. The bioassay results indicated that the title compounds exhibit good insecticidal activity, especially towards Plutella xylostella L., but had lower fungicidal activity. Inspiringly, the title compounds possessed obvious anticancer activity against human promyelocytic leukemic cell line (HL-60, and some of the title compounds also had activity against human hepatocellular carcinoma cell line (Bel-7402, human gastric carcinoma cell line (BGC-823, and human nasopharyngeal carcinoma cell line (KB. The results indicated that the linkage in the lead compounds was important to the bioactivity and spectra. The modification on the urea linkage is an effective strategy to discover new pesticide and drug candidates.

  15. GRAFTING OF PEROXIDE-INITIATED MALEIC ANHYDRIDE ON SPHERICAL PE/PP IN-REACTOR BLEND GRANULES

    Institute of Scientific and Technical Information of China (English)

    Yan-zhong Zhang; Zhi-qiang Fan; Bai-geng Wu; Jun-ting Xu; Qi Wang

    2004-01-01

    Spherical polyethylene/polypropylene (PE/PP) in-reactor blend granules with various ethylene/propylene molar ratios and high porosity were synthesized using a high yield TiCl4/MgCl2 supported catalyst. A solution of benzoyl peroxide (BPO)/maleic anhydride (MAH)/xylene (interfacial reagent) or BPO/MAH/St (comonomer) was absorbed onto the PE/PP inreactor blend granules, and solid phase graft polymerization of MAH on PE/PP was conducted. The amount of grafted MAH on PE/PP was measured through chemical titration. The results showed that solid phase graft polymerization of MAH in PE/PP in-reactor blend granules produced graft copolymer with high amount of grafted MAH, and the amount of grafted MAH was raised slightly when St was introduced as comonomer. The graft in-reactor blend was fractionated into five fractions through temperature-gradient extraction fractionation (TGEF), and the fractions were analyzed by FTIR. The results revealed that MAH is mainly grafted on the PE segments, whereas MAH was predominantly grafted on the PP segments when St was present in the graft polymerization system. In addition, the final product is still in the form of regular spherical granules, which is beneficial for industrial processing.

  16. Lipid peroxidation in adrenal and testicular microsomes.

    OpenAIRE

    1981-01-01

    Studies were carried out to determine the actions of and interactions between ascorbate, NADPH, Fe2+, and Fe3+ on lipid peroxidation in adrenal and testicular microsomes. Ascorbate-induced malonaldehyde production was maximal in adrenal and testicular microsomes at an ascorbate concentration of 1 X 10(-4)M. Fe2+, at levels between 10(-6) and 10(-3)M, produced concentration-dependent increases in lipid peroxidation in adrenal and testicular microsomes; Fe2+ had a far greater effect than Fe3+ i...

  17. Phytic Acid Inhibits Lipid Peroxidation In Vitro

    OpenAIRE

    Alicja Zajdel; Adam Wilczok; Ludmiła Węglarz; Zofia Dzierżewicz

    2013-01-01

    Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the deca...

  18. Reactive Oxygen Species, Lipid Peroxidation and Antioxidative Defense Mechanism

    Directory of Open Access Journals (Sweden)

    Hossam S. EL-BELTAGI

    2013-05-01

    Full Text Available Lipid peroxidation can be defined as the oxidative deterioration of lipids containing any number of carbon-carbon double bonds. Lipid peroxidation is a well-established mechanism of cellular injury in both plants and animals, and is used as an indicator of oxidative stress in cells and tissues. Lipid peroxides are unstable and decompose to form a complex series of compounds including reactive carbonyl compounds. The oxidation of linoleates and cholesterol is discussed in some detail. Analytical methods for studying lipid peroxidation were mentioned. Various kinds of antioxidants with different functions inhibit lipid peroxidation and the deleterious effects caused by the lipid peroxidation products.

  19. Involvement of lipid peroxidation and organic peroxides in UVA-induced matrix metalloproteinase-1 expression.

    Science.gov (United States)

    Polte, Tobias; Tyrrell, Rex M

    2004-06-15

    Ultraviolet A (UVA) irradiation causes human skin aging and skin cancer at least partially through the activation of matrix metalloproteinases (MMPs). MMP-1, the interstitial collagenase, is responsible for the degradation of collagen and is involved in tumor progression in human skin. The present study uses human skin fibroblast cells (FEK4) to investigate the involvement of lipid peroxidation and the role of peroxides as possible mediators in MMP-1 activation by UVA. Preincubation with the antioxidants butylated hydroxytoluene and Trolox reduced UVA-dependent MMP-1 upregulation, suggesting that peroxidation of membrane lipids is involved. Blocking the iron-driven generation of lipid peroxides and hydroxyl radicals by different iron chelators led to a decrease in UVA-induced MMP-1 mRNA accumulation. Moreover, modulation of glutathione peroxidase activity by use of the specific inhibitor mercaptosuccinate (MS) or by the depletion of glutathione (using buthionine-S, R-sulfoximine, BSO), enhanced the UVA-dependent MMP-1 response. Finally, UVA irradiation generated a significant increase in intracellular peroxide levels which is augmented by pretreatment of the cells with BSO or MS. Our results demonstrate that lipid peroxidation and the production of peroxides are important events in the signalling pathway of MMP-1 activation by UVA.

  20. Correlation of the solid-state reactivities of racemic 2,4(6)-di-O-benzoyl-myo-inositol 1,3,5-orthoformate and its 4,4'-bipyridine cocrystal with their crystal structures.

    Science.gov (United States)

    Tamboli, Majid I; Bahadur, Vir; Gonnade, Rajesh G; Shashidhar, Mysore S

    2014-11-01

    Racemic 2,4(6)-di-O-benzoyl-myo-inositol 1,3,5-orthoformate, C21H18O8, (1), shows a very efficient intermolecular benzoyl-group migration reaction in its crystals. However, the presence of 4,4'-bipyridine molecules in its cocrystal, C21H18O8·C10H8N2, (1)·BP, inhibits the intermolecular benzoyl-group transfer reaction. In (1), molecules are assembled around the crystallographic twofold screw axis (b axis) to form a helical self-assembly through conventional O-H···O hydrogen-bonding interactions. This helical association places the reactive C6-O-benzoyl group (electrophile, El) and the C4-hydroxy group (nucleophile, Nu) in proximity, with a preorganized El···Nu geometry favourable for the acyl transfer reaction. In the cocrystal (1)·BP, the dibenzoate and bipyridine molecules are arranged alternately through O-H···N interactions. The presence of the bipyridine molecules perturbs the regular helical assembly of the dibenzoate molecules and thus restricts the solid-state reactivity. Hence, unlike the parent dibenzoate crystals, the cocrystals do not exhibit benzoyl-transfer reactions. This approach is useful for increasing the stability of small molecules in the crystalline state and could find application in the design of functional solids.

  1. Virucidal efficacy of hydrogen peroxide vapour disinfection

    NARCIS (Netherlands)

    Tuladhar, E.; Terpstra, P.; Koopmans, M.; Duizer, E.

    2012-01-01

    Background: Viral contamination of surfaces is thought to be important in transmission. Chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (HPV) against enteric and respiratory viruses. Aim: To measure the vir

  2. Drinking Peroxide as 'Natural' Cure Leads to Dangerous Blood Clots

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_163513.html Drinking Peroxide as 'Natural' Cure Leads to Dangerous Blood Clots ... 9, 2017 (HealthDay News) -- Ingesting high-concentration hydrogen peroxide as a "natural cure" or cleansing agent may ...

  3. Systems and methods for generation of hydrogen peroxide vapor

    Science.gov (United States)

    Love, Adam H; Eckels, Joel Del; Vu, Alexander K; Alcaraz, Armando; Reynolds, John G

    2014-12-02

    A system according to one embodiment includes a moisture trap for drying air; at least one of a first container and a second container; and a mechanism for at least one of: bubbling dried air from the moisture trap through a hydrogen peroxide solution in the first container for producing a hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above a hydrogen peroxide solution in the second container for producing a hydrogen peroxide vapor. A method according one embodiment includes at least one of bubbling dried air through a hydrogen peroxide solution in a container for producing a first hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above the hydrogen peroxide solution in a container for producing a second hydrogen peroxide vapor. Additional systems and methods are also presented.

  4. Microsomal lipid peroxidation as a mechanism of cellular damage. [Dissertation

    Energy Technology Data Exchange (ETDEWEB)

    Kornbrust, D.J.

    1979-01-01

    The NADPH/iron-dependent peroxidation of lipids in rat liver microsomes was found to be dependent on the presence of free ferrous ion and maintains iron in the reduced Fe/sup 2 +/ state. Chelation of iron by EDTA inhibited peroxidation. Addition of iron, after preincubation of microsomes in the absence of iron, did not enhance the rate of peroxidation suggesting that iron acts by initiating peroxidative decomposition of membrane lipids rather than by catalyzing the breakdown of pre-formed hydroperoxides. Liposomes also underwent peroxidation in the presence of ferrous iron at a rate comparable to intact microsomes and was stimulated by ascorbate. Carbon tetrachloride initiated lipid peroxidation in the absence of free metal ions. Rates of in vitro lipid peroxidation of microsomes and homogenates were found to vary widely between different tissues and species. The effects of paraquat on lipid peroxidation was also studied. (DC)

  5. Synthesis, PASS-Predication and in Vitro Antimicrobial Activity of Benzyl 4-O-benzoyl-α-l-rhamnopyranoside Derivatives.

    Science.gov (United States)

    Matin, Mohammed Mahbubul; Nath, Amit R; Saad, Omar; Bhuiyan, Mohammad M H; Kadir, Farkaad A; Abd Hamid, Sharifah Bee; Alhadi, Abeer A; Ali, Md Eaqub; Yehye, Wageeh A

    2016-08-27

    Benzyl α-l-rhamnopyranoside 4, obtained by both conventional and microwave assisted glycosidation techniques, was subjected to 2,3-O-isopropylidene protection to yield compound 5 which on benzoylation and subsequent deprotection of isopropylidene group gave the desired 4-O-benzoylrhamnopyranoside 7 in reasonable yield. Di-O-acetyl derivative of benzoate 7 was prepared to get newer rhamnopyranoside. The structure activity relationship (SAR) of the designed compounds was performed along with the prediction of activity spectra for substances (PASS) training set. Experimental studies based on antimicrobial activities verified the predictions obtained by the PASS software. Protected rhamnopyranosides 5 and 6 exhibited slight distortion from regular ¹C₄ conformation, probably due to the fusion of pyranose and isopropylidene ring. Synthesized rhamnopyranosides 4-8 were employed as test chemicals for in vitro antimicrobial evaluation against eight human pathogenic bacteria and two fungi. Antimicrobial and SAR study showed that the rhamnopyranosides were prone against fungal organisms as compared to that of the bacterial pathogens. Interestingly, PASS prediction of the rhamnopyranoside derivatives 4-8 were 0.49 < Pa < 0.60 (where Pa is probability 'to be active') as antibacterial and 0.65 < Pa < 0.73 as antifungal activities, which showed significant agreement with experimental data, suggesting rhamnopyranoside derivatives 4-8 were more active against pathogenic fungi as compared to human pathogenic bacteria thus, there is a more than 50% chance that the rhamnopyranoside derivative structures 4-8 have not been reported with antimicrobial activity, making it a possible valuable lead compound.

  6. Synthesis, PASS-Predication and in Vitro Antimicrobial Activity of Benzyl 4-O-benzoyl-α-l-rhamnopyranoside Derivatives

    Science.gov (United States)

    Matin, Mohammed Mahbubul; Nath, Amit R.; Saad, Omar; Bhuiyan, Mohammad M. H.; Kadir, Farkaad A.; Abd Hamid, Sharifah Bee; Alhadi, Abeer A.; Ali, Md. Eaqub; Yehye, Wageeh A.

    2016-01-01

    Benzyl α-l-rhamnopyranoside 4, obtained by both conventional and microwave assisted glycosidation techniques, was subjected to 2,3-O-isopropylidene protection to yield compound 5 which on benzoylation and subsequent deprotection of isopropylidene group gave the desired 4-O-benzoylrhamnopyranoside 7 in reasonable yield. Di-O-acetyl derivative of benzoate 7 was prepared to get newer rhamnopyranoside. The structure activity relationship (SAR) of the designed compounds was performed along with the prediction of activity spectra for substances (PASS) training set. Experimental studies based on antimicrobial activities verified the predictions obtained by the PASS software. Protected rhamnopyranosides 5 and 6 exhibited slight distortion from regular 1C4 conformation, probably due to the fusion of pyranose and isopropylidene ring. Synthesized rhamnopyranosides 4–8 were employed as test chemicals for in vitro antimicrobial evaluation against eight human pathogenic bacteria and two fungi. Antimicrobial and SAR study showed that the rhamnopyranosides were prone against fungal organisms as compared to that of the bacterial pathogens. Interestingly, PASS prediction of the rhamnopyranoside derivatives 4–8 were 0.49 < Pa < 0.60 (where Pa is probability ‘to be active’) as antibacterial and 0.65 < Pa < 0.73 as antifungal activities, which showed significant agreement with experimental data, suggesting rhamnopyranoside derivatives 4–8 were more active against pathogenic fungi as compared to human pathogenic bacteria thus, there is a more than 50% chance that the rhamnopyranoside derivative structures 4–8 have not been reported with antimicrobial activity, making it a possible valuable lead compound. PMID:27618893

  7. Expanding the crystal chemistry of uranyl peroxides: four hybrid uranyl-peroxide structures containing EDTA.

    Science.gov (United States)

    Qiu, Jie; Ling, Jie; Sieradzki, Claire; Nguyen, Kevin; Wylie, Ernest M; Szymanowski, Jennifer E S; Burns, Peter C

    2014-11-17

    The first four uranyl peroxide compounds containing ethylenediaminetetra-acetate (EDTA) were synthesized and characterized from aqueous uranyl peroxide nitrate solutions with a pH range of 5-7. Raman spectra demonstrated that reaction solutions that crystallized [NaK15[(UO2)8(O2)8(C10H12O10N2)2(C2O4)4]·(H2O)14] (1) and [Li4K6[(UO2)8(O2)6(C10H12O10N2)2(NO3)6]·(H2O)26] (2) contained excess peroxide, and their structures contained oxidized ethylenediaminetetraacetate, EDTAO2(4-). The solutions from which [K4[(UO2)4(O2)2(C10H13O8N2)2(IO3)2]·(H2O)16] (3) and LiK3[(UO2)4(O2)2(C10H12O8N2)2(H2O)2]·(H2O)18 (4) crystallized contained no free peroxide, and the structures incorporated intact EDTA(4-). In contrast to the large family of uranyl peroxide cage clusters, coordination of uranyl peroxide units in 1-4 by EDTA(4-) or EDTAO2(4-) results in isolated tetramers or dimers of uranyl ions that are bridged by bidentate peroxide groups. Two tetramers are bridged by EDTAO2(4-) to form octamers in 1 and 2, and dimers of uranyl polyhedra are linked through iodate groups in 3 and EDTA(4-) in 4, forming chains in both cases. In each structure the U-O2-U dihedral angle is strongly bent, at ∼140°, consistent with the configuration of this linkage in cage clusters and other recently reported uranyl peroxides.

  8. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell

    OpenAIRE

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D.

    2012-01-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the ...

  9. Para-(benzoyl)-phenylalanine as a potential inhibitor against LpxC of Leptospira spp.: homology modeling, docking, and molecular dynamics study.

    Science.gov (United States)

    Pradhan, Dibyabhaba; Priyadarshini, Vani; Munikumar, Manne; Swargam, Sandeep; Umamaheswari, Amineni; Bitla, Aparna

    2014-01-01

    Leptospira interrogans, a Gram-negative bacterial pathogen is the main cause of human leptospirosis. Lipid A is a highly immunoreactive endotoxic center of lipopolysaccharide (LPS) that anchors LPS into the outer membrane of Leptospira. Discovery of compounds inhibiting lipid-A biosynthetic pathway would be promising for dissolving the structural integrity of membrane leading to cell lysis and death of Leptospira. LpxC, a unique enzyme of lipid-A biosynthetic pathway was identified as common drug target of Leptospira. Herein, homology modeling, docking, and molecular dynamics (MD) simulations were employed to discover potential inhibitors of LpxC. A reliable tertiary structure of LpxC in complex with inhibitor BB-78485 was constructed in Modeller 9v8. A data-set of BB-78485 structural analogs were docked with LpxC in Maestro v9.2 virtual screening workflow, which implements three stage Glide docking protocol. Twelve lead molecules with better XP Gscore compared to BB-78485 were proposed as potential inhibitors of LpxC. Para-(benzoyl)-phenylalanine - that showed lowest XP Gscore (-10.35 kcal/mol) - was predicted to have best binding affinity towards LpxC. MD simulations were performed for LpxC and para-(benzoyl)-phenylalanine docking complex in Desmond v3.0. Trajectory analysis showed the docking complex and inter-molecular interactions was stable throughout the entire production part of MD simulations. The results indicate para-(benzoyl)-phenylalanine as a potent drug molecule against leptospirosis. An animated Interactive 3D Complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:10.

  10. 49 CFR 172.552 - ORGANIC PEROXIDE placard.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false ORGANIC PEROXIDE placard. 172.552 Section 172.552... SECURITY PLANS Placarding § 172.552 ORGANIC PEROXIDE placard. (a) Except for size and color, the ORGANIC... background on the ORGANIC PEROXIDE placard must be red in the top half and yellow in the lower half. The...

  11. 49 CFR 172.427 - ORGANIC PEROXIDE label.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false ORGANIC PEROXIDE label. 172.427 Section 172.427... SECURITY PLANS Labeling § 172.427 ORGANIC PEROXIDE label. (a) Except for size and color, the ORGANIC... on the ORGANIC PEROXIDE label must be red in the top half and yellow in the lower half....

  12. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric...

  13. N-benzoyl-1,5-benzothiazepine and its S-oxide as vasopressin receptor ligands: insight into the active stereochemistry around the seven-membered ring.

    Science.gov (United States)

    Yoneda, Tetsuya; Tabata, Hidetsugu; Tasaka, Tomohiko; Oshitari, Tetsuta; Takahashi, Hideyo; Natsugari, Hideaki

    2015-04-09

    The stereochemistry of N-benzoyl-1,5-benzothiazepine and its S-oxide derivatives as vasopressin receptor ligands was examined in detail by freezing the conformation with a methyl group at the C6 or C9 of 1,5-benzothiazepine. It was revealed that the active forms recognized by the receptors are (cis,aS) for 1,5-benzothiazepine (5-7)-II and (cis,1S,aS) (syn) for its S-oxide (8-10)-II. The C9-methyl derivative of 1,5-benzothiazepine S-oxide (10-II) was designed and synthesized, achieving the putative active syn-isomer.

  14. Synthesis and relaxivity of polycarboxylic hydrazone rare earth complexes--Relaxivity of a -oxo-pentanedioic acid benzoyl hydrazone Gd-complexes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Synthesis of ligand, a -oxo-pentanedioic acid benzoyl hydrazone (H2LPB), and its six rare earth (La, Pr, Nd, Sm, Gd and Er) complexes are reported. The composition and the properties of the complexes were characterized by element analysis, thermal analysis, UV, IR and 1H NMR spectra. Besides, relaxivity (R1) of Gd-complex has been determined by INVREC.Au program, using inversion recovery pulse sequences, R1=8.05 mmol.L-1.s-1. The acute toxicity of Gd-complex in animal has also been tested, and the median lethal dose (LD50) is equal to (468.2±30) mg/kg.

  15. Synthesis of new 2-acetyl and 2-benzoyl quinoxaline 1,4-di-N-oxide derivatives as anti-Mycobacterium tuberculosis agents.

    Science.gov (United States)

    Jaso, Andrés; Zarranz, Belén; Aldana, Ignacio; Monge, Antonio

    2003-09-01

    A series of 2-acetyl and 2-benzoyl-6(7)-substituted quinoxaline 1,4-di-N-oxide derivatives were synthesized and evaluated for in vitro antituberculosis activity. The results show that 2-acetyl-3-methylquinoxaline 1,4-di-N-oxide derivatives with chlorine, methyl or methoxy group in position 7 of the benzene moiety (compounds 2, 4 and 6, respectively) and unsubstituted (3) have good antitubercular activity, exhibiting EC(90)/MIC values between 0.80 and 4.29. In conclusion, the potency, selectivity and low cytotoxicity of these compounds make them valid leads for synthesizing new compounds that possess better activity.

  16. The lipid peroxidation in breast cancer patients.

    Science.gov (United States)

    Kedzierska, Magdalena; Olas, Beata; Wachowicz, Barbara; Jeziorski, Arkadiusz; Piekarski, Janusz

    2010-06-01

    The aim of our study was to estimate oxidative stress (by using different biomarkers of lipid peroxidation--isoprostanes and thiobarbituric acid reactive substances (TBARS)) in patients with invasive breast cancer, patients with benign breast diseases and in a control group. We observed a statistically increased level of TBARS in plasma and isoprostanes in urine of patients with invasive breast cancer in comparison with a control group. The concentration of tested biomarkers in plasma or urine from patients with invasive breast cancer was also higher than in patients with benign breast diseases. Moreover, the levels of tested markers in patients with benign breast diseases and in a control group did not differ. Considering the data presented in this study, we suggest that free radicals induce peroxidation of unsaturated fatty acid in patients with breast cancer.

  17. Materials Compatibility in High Test Hydrogen Peroxide

    Science.gov (United States)

    Gostowski, Rudy

    1999-01-01

    Previous ratings of the compatibility of high test hydrogen peroxide (HTP) with materials are not adequate for current needs. The goal of this work was to develop a new scheme of evaluation of compatibility of HTP with various materials. Procedures were developed to enrich commercially available hydrogen peroxide to 90% concentration and to assay the product. Reactivity testing, accelerated aging of materials and calorimetry studies were done on HTP with representative metallic and non-metallic materials. It was found that accelerated aging followed by concentration determination using refractive index effectively discriminated between different Class 2 metallic materials. Preliminary experiments using Differential Scanning Calorimetry (DSC) suggest that a calorimetry experiment is the most sensitive means to assay the compatibility of HTP with materials.

  18. Functionalized Palladium Nanoparticles for Hydrogen Peroxide Biosensor

    Directory of Open Access Journals (Sweden)

    H. Baccar

    2011-01-01

    Full Text Available We present a comparison between two biosensors for hydrogen peroxide (H2O2 detection. The first biosensor was developed by the immobilization of Horseradish Peroxidase (HRP enzyme on thiol-modified gold electrode. The second biosensor was developed by the immobilization of cysteamine functionalizing palladium nanoparticles on modified gold surface. The amino groups can be activated with glutaraldehyde for horseradish peroxidase immobilization. The detection of hydrogen peroxide was successfully observed in PBS for both biosensors using the cyclic voltammetry and the chronoamperometry techniques. The results show that the limit detection depends on the large surface-to-volume ratio attained with palladium nanoparticles. The second biosensor presents a better detection limit of 7.5 μM in comparison with the first one which is equal to 75 μM.

  19. Hydrogen Peroxide Propulsion for Smaller Satellites

    OpenAIRE

    Whitehead, John

    1998-01-01

    As satellite designs shrink, providing maneuvering and control capability falls outside the realm of available propulsion technology. While cold gas has been used on the smallest satellites, hydrogen peroxide propellant is suggested as the next step in performance and cost before hydrazine. Minimal toxicity and a small scale enable bench top propellant preparation and development testing. Progress toward low-cost thrusters and self-pressurizing tank systems is described.

  20. Inactivation of human myeloperoxidase by hydrogen peroxide.

    Science.gov (United States)

    Paumann-Page, Martina; Furtmüller, Paul G; Hofbauer, Stefan; Paton, Louise N; Obinger, Christian; Kettle, Anthony J

    2013-11-01

    Human myeloperoxidase (MPO) uses hydrogen peroxide generated by the oxidative burst of neutrophils to produce an array of antimicrobial oxidants. During this process MPO is irreversibly inactivated. This study focused on the unknown role of hydrogen peroxide in this process. When treated with low concentrations of H2O2 in the absence of reducing substrates, there was a rapid loss of up to 35% of its peroxidase activity. Inactivation is proposed to occur via oxidation reactions of Compound I with the prosthetic group or amino acid residues. At higher concentrations hydrogen peroxide acts as a suicide substrate with a rate constant of inactivation of 3.9 × 10(-3) s(-1). Treatment of MPO with high H2O2 concentrations resulted in complete inactivation, Compound III formation, destruction of the heme groups, release of their iron, and detachment of the small polypeptide chain of MPO. Ten of the protein's methionine residues were oxidized and the thermal stability of the protein decreased. Inactivation by high concentrations of H2O2 is proposed to occur via the generation of reactive oxidants when H2O2 reacts with Compound III. These mechanisms of inactivation may occur inside neutrophil phagosomes when reducing substrates for MPO become limiting and could be exploited when designing pharmacological inhibitors.

  1. Cumene peroxide and Fe(2+)-ascorbate-induced lipid peroxidation and effect of phosphoglucose isomerase.

    Science.gov (United States)

    Agadjanyan, Z S; Dugin, S F; Dmitriev, L F

    2006-09-01

    Malondialdehyde (MDA) is one of cytotoxic aldehydes produced in cells as a result of lipid peroxidation and further MDA metabolism in cytoplasm is not known. In our experiments the liver fraction 10,000 g containing phosphoglucose isomerase and enzymes of the glyoxalase system was used and obtained experimental data shows that in this fraction there is an aggregate of reactions taking place both in membranes (lipid peroxidation) and outside membranes. MDA accumulation is relatively slow because MDA is a substrate of aldehyde isomerase (MDA methylglyoxal). The well known enzyme phosphoglucose isomerase acts as an aldehyde isomerase (Michaelis constant for this enzyme Km = 133 +/- 8 microM). MDA conversion to methylglyoxal and further to neutral product D-lactate (with GSH as a cofactor) occurs in cytoplasm and D-lactate should be regarded as the end product of two different parametabolic reactions: lipid peroxidation or protein glycation.

  2. Hydrogen peroxide stabilization in one-dimensional flow columns

    Science.gov (United States)

    Schmidt, Jeremy T.; Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.

    2011-09-01

    Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H 2O 2 propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.

  3. KINETICS OF HYDROLYSIS IN AQUEOUS-SOLUTION OF 1-BENZOYL-1,2,4-TRIAZOLE - THE ROLE OF PAIRWISE AND TRIPLET GIBBS ENERGY INTERACTION PARAMETERS IN DESCRIBING THE EFFECTS OF ADDED SALTS AND ADDED ALCOHOLS

    NARCIS (Netherlands)

    NOORDMAN, WH; BLOKZIJL, W; ENGBERTS, JBF; BLANDAMER, MJ

    1995-01-01

    Kinetic data are reported for the spontaneous hydrolysis of 1-benzoyl-1,2,4-triazole in aqueous solutions at ambient-pressure and 298.2 K, in aqueous solutions containing added ethanol, propanol and sodium chloride. Kinetic-data are also reported for the same reaction in aqueous mixtures of sodium c

  4. Kinetics of hydrolysis in aqueous solution of 1-benzoyl-1,2,4-triazole; the role of pairwise and triplet Gibbs energy interaction parameters in describing the effects of added salts and added alcohols

    NARCIS (Netherlands)

    Noordman, Wouter H.; Blokzijl, Wilfried; Engberts, Jan B.F.N.; Blandamer, Michael J.

    1995-01-01

    Kinetic data are reported for the spontaneous hydrolysis of 1-benzoyl-1,2,4-triazole in aqueous solutions at ambient pressure and 298.2 K, in aqueous solutions containing added ethanol, propanol and sodium chloride. Kinetic data are also reported for the same reaction in aqueous mixtures of sodium c

  5. Correlations Between retention indices and molecular structure of aliphatic alcohols and of their benzoyl derivatives on phenyl substituted polysiloxane stationary phases; Cromatografia en fase gaseosa sobre metilfenilpolisiloxanos. Estructura molecular y parametros de retencion para alcoholes y sus derivados benzoilados

    Energy Technology Data Exchange (ETDEWEB)

    Pias, J. B.; Gasco, L.

    1976-07-01

    The retention indices of aliphatic alcohols of carbon number up to C{sub g}, and of their benzoyl derivatives up to C{sub 7}, were determined in columns packed with Chromo sorb G (AW-DMCS-HP) coated previously with 5% methyl, and methyl phenyl polysiloxanes with increasing polarity (SE-30, 0V-3, 0V-7, 0V-11, 0V-17 and OV-25). Correlations between retention indices and chain length for 1-alcohols, 2-alcohols, 3-alcohols, 1 , on -3-alcohols, 2-methyl-1-alcohols and for their corresponding benzoyl derivatives were calculated at 100, 120 and 140 degree centigree. In alcohols, a -CH{sub 2}- group increases I approximately 100 units, and in their benzoyl derivatives from 80 to 100 units. Dispersion indices {delta}l , and positional and structural increments {delta}I, were evaluated for -OH and benzoyl groups in terms of phase polarity and chain length. Effects of chain length, chain branching and double bond location on retention parameters were also studied. (Author) 23 refs.

  6. Determination of the Tautomeric Equilibria of Pyridoyl Benzoyl -Diketones in the Liquid and Solid State through the use of Deuterium Isotope Effects on 1H and 13C NMR Chemical Shifts and Spin Coupling Constants

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Borisov, Eugeny V.; Lindon, John C.

    2015-01-01

    The tautomeric equilibria for 2-pyridoyl-, 3-pyridoyl-, and 4-pyridoyl-benzoyl methane have been investigated using deuterium isotope effects on 1H and 13C chemical shifts both in the liquid and the solid state. Equilibria are established both in the liquid and the solid state. In addition, in th...

  7. Low-valent Titanium Induced Reductive Coupling of o-Nitro-phenylazide with Benzoyl Substituted Ketene Dithioacetals: a Novel Synthesis of 4-Aryl-2-methylthio-3H-1,5-benzodiazepines

    Institute of Scientific and Technical Information of China (English)

    李志芳; 张永敏

    2001-01-01

    Treated with the low-valent titanium derived from TiCl4/Sm system, o-nitrophenylazide could produce the intermediate 2in situ, which reacted with benzoyl substituted ketene dithioacetals to afford 4-aryl-2-methylthio-3H-1,5-benzodiazepines in good yields under mild and neutral conditions.

  8. Kinetics of hydrolysis of 1-benzoyl-1,2,4-triazole in aqueous solution as a function of temperature near the temperature of maximum density, and the isochoric controversy

    NARCIS (Netherlands)

    Blandamer, MJ; Buurma, NJ; Engberts, JBFN; Reis, JCR; Buurma, Niklaas J.; Reis, João C.R.

    2003-01-01

    At temperatures above and below the temperature of maximum density, TMD, for water at ambient pressure, pairs of temperatures exist at which the molar volumes of water are equal. First-order rate constants for the pH-independent hydrolysis of 1-benzoyl-1,2,4-triazole in aqueous solution at pairs of

  9. Lipid peroxidation in women with epilepsy

    Directory of Open Access Journals (Sweden)

    Deepa D

    2008-01-01

    Full Text Available Background: Lipid peroxidation is an indicator of free radical metabolism and oxidative stress in human beings and other organisms. Malondialdehyde (MDA, an end product of lipid peroxidation, is a metabolite that can be readily estimated in serum samples. Excess oxidative stress may be a final common pathway through which anti epileptic drugs may exert their teratogenic potential in pregnant women with epilepsy. Our objective in this study was to ascertain the variations in malondialdehyde (MDA in women with epilepsy. Material and Methods: This study was carried out in the Kerala Registry of Epilepsy and pregnancy after obtaining clearance from the Institutional Ethics Committee. Informed consent was obtained from all the subjects. The quantitative examination of MDA was performed according to standard procedures. The ideal plasma level of MDA is below 2 nmol/ml. Results: Fifteen women with confirmed epilepsy (mean age 26.9 ± 3.5 were included in the study. Two women were pregnant. MDA levels ranged from 1.7 to 2.8 nmol/ml (mean level = 2.13 ± 0.37 nmol/ml. Eight women (53 % had MDA levels above the upper limit of normal. Three patients had levels above 2.5 nmol/ml, which corresponded to the 75 centile. Conclusions: This study had shown that the estimation of MDA levels in plasma is a convenient method to study lipid peroxidation and thereby oxidative stress in women with epilepsy. Over half of Women With Epilepsy (WWE have excess oxidative stress as indicated by high levels of MDA in the plasma. Correlations between MDA level and characteristics of epilepsy, AED therapy, nutritional status and other medical conditions need to be observed in a larger cohort.

  10. Reactive extraction for preparation of hydrogen peroxide under pressure

    Institute of Scientific and Technical Information of China (English)

    Yongxi CHENG; Hongtao LI; Shuxiang L(U); Li WANG

    2008-01-01

    The preparation of hydrogen peroxide from anthrahydroquinone by reactive extraction was investi-gated.The integration process of oxidation of anthrahydro-quinone by air and extraction of hydrogen peroxide from the organic phase with water was carried out in a sieve plate column under'pressure.The conversion of anthrahydroqui-none increased with increasing pressure resulting in an increase of hydrogen peroxide concentration in the aqueous phase.However,no change in extraction efficiency of hydrogen peroxide was observed.A mathematical model for gas-liquid-liquid reactive extraction was established.In the model,the effects of pressure and gas superficial velocity on reaction were considered.With increasing gas superficial velocity,the conversion of anthrahydroquinone increased,and the fraction of hydrogen peroxide extracted reached a plateau with a maximum of 72.94%.However,both the conversion of anthrahydroquinone and the traction of hydrogen peroxide extracted decreased with increasing organic phase superficial velocity.

  11. Use of Hydrogen Peroxide to Disinfect Hydroponic Plant Growth Systems

    Science.gov (United States)

    Barta, Daniel J.; Henderson, Keith

    2000-01-01

    Hydrogen peroxide was studied as an alternative to conventional bleach and rinsing methods to disinfect hydroponic plant growth systems. A concentration of 0.5% hydrogen peroxide was found to be effective. Residual hydrogen peroxide can be removed from the system by repeated rinsing or by flowing the solution through a platinum on aluminum catalyst. Microbial populations were reduced to near zero immediately after treatment but returned to pre-disinfection levels 2 days after treatment. Treating nutrient solution with hydrogen peroxide and planting directly into trays being watered with the nutrient solution without replenishment, was found to be detrimental to lettuce germination and growth.

  12. Detection of volatile organic peroxides in indoor air.

    Science.gov (United States)

    Hong, J; Maguhn, J; Freitag, D; Kettrup, A

    2001-12-01

    A supercritical fluid extraction cell filled with adsorbent (Carbotrap and Carbotrap C) was used directly as a sampling tube to enrich volatile organic compounds in air. After sampling, the analytes were extracted by supercritical fluid CO2 with methanol as modifier. Collected organic peroxides were then determined by a RP-HPLC method developed and validated previously using post-column derivatization and fluorescence detection. Some volatile organic peroxides were found in indoor air in a new car and a newly decorated kitchen in the lower microg m(-3) range. tert-Butyl perbenzoate, di-tert-butyl peroxide, and tert-butylcumyl peroxide could be identified.

  13. Effect of carbamide peroxide and hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings.

    Science.gov (United States)

    Rostein, I; Cohenca, N; Mor, C; Moshonov, J; Stabholz, A

    1995-12-01

    The effect of 10% carbamide peroxide or 10% hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings was tested. Ninety IRM samples were treated with either 10% carbamide peroxide, 10% hydrogen peroxide or phosphate buffer which served as control. Treatment consisted of placing the samples in a dry incubator at 37 degrees C for 1, 3 or 7 days. At each time point, the samples were removed from the test solutions, dried and prepared for surface scanning electron microscopy and energy dispersive spectrometric analysis. After 3 days, 10% carbamide peroxide significantly reduced the zinc oxide levels as compared to the 10% hydrogen peroxide group (IRM fillings, but their modes of action differed.

  14. Use of neutral capillaries for the enantioseparation of N-benzoylated amino acids by capillary electrophoresis with bromobalhimycin as chiral selector.

    Science.gov (United States)

    Peng, Yongbo; Zhang, Tingting; Wang, Tingting; Liu, Zhenghua; Crommen, Jacques; Jiang, Zhengjin

    2013-05-01

    In this study, the partial filling technique on both polycationic polymer hexadimethrine bromide (HDB) modified capillary and eCAP neutral capillary were systematically compared in order to enhance the enantioseparation ability of bromobalhimycin as CE additive. The separation conditions, such as pH, the plug length, and the concentration of bromobalhimycin, etc., were optimized in order to obtain satisfactory separations. As expected, for all tested 28 N-benzoylated amino acids, up to five times higher enantioresolutions were obtained on the eCAP neutral capillary compared to that on the polycationic polymer hexadimethrine bromide modified capillary. Moreover, 26 of 28 tested racemic compounds were almost baseline- resolved without observing any interference from the front of the plug of bromobalhimycin. Although the limitation of longer running time on the neutral capillary, it allows the use of higher content of bromobalhimycin in the running buffer without any interference on the detection of analytes when enantioseparations are more difficult to obtain.

  15. Synthesis, Structure Characterization, and Cu2+ Recognition of 3-{[3-(Phenylsulfonamido)benzoyl]methylidene}-3,4-dihydroquinoxaline-2(1H)-one

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Aryl diketo acid derivatives are one of the most promising HIV-1 integrase(IN) inhibitors. With a view to substitute the critical diketo acid pharmacophore with the diketo benzimidazole unit, the coupling reaction of compound 4 with o -phenylenediamine was carried out. However, the reaction product, compound 5, was confirmed to be 3-{[3-(phenylsulfonamido)benzoyl]methylidene}-3,4-dihydroquinoxaline-2(1H)-one rather than the2-benzimidazole derivative by using X-ray diffraction. Owing to its low solubility in water, the evaluation of the anti-HIV IN activity of the synthesized compound 5 could not be carried out. Consequently, the ion-binding properties of compound 5 in the absence of HIV-1 IN were investigated with UV-Vis spectroscopy in organic solvents. The results show that such a compound can selectively recognize Cu2+ .

  16. SYNTHESIS, COMPUTATIONAL STUDY AND PRELIMINARY PHARMACOLOGICAL EVALUATION OF 2-[4-(2-CHLOROBENZYL/BENZOYL SUBSTITUTED PIPERAZIN-1-YL]-N-PHENYLACETAMIDE: POTENTIAL ANTIPSYCHOTICS

    Directory of Open Access Journals (Sweden)

    Tomar Amita

    2011-06-01

    Full Text Available Benzyl and benzoyl substituted acetamides have been synthesized and evaluated as potential antipsychotic agents. The target compounds (4a-b were prepared by reaction of substituted anilines with chloroacetylchloride which further treated with 2-chlorobenzyl or 2-chlorobenzoyl piperazine in presence of potassium carbonate and potassium iodide as catalyst in acetonitrile. The structures of the target compounds (4a-b were characterized on the basis of their M.P., TLC, IR and 1H-NMR data. Computational studies of target compounds (4a-b were carried out by using software programs. The target compounds showed good similarity with respect to standard drugs. The target compounds (4a-b showed inhibition of 5-HTP induced head twitches behavior and low induction of catalepsy in mice.

  17. Vibrational and theoretical analysis of pentyl-4-benzoyl-1-[2,4-dinitrophenyl]-5-phenyl-1H-pyrazole-3-carboxylate

    Science.gov (United States)

    Arı, Hatice; Büyükmumcu, Zeki; Özpozan, Talat; İlhan, İlhan Özer; Bahadır, Özlem

    2013-06-01

    Infrared spectrum of the compound, pentyl-4-benzoyl-1-[2,4-dinitrophenyl]-5-phenyl-1H-pyrazole-3-carboxylate (PBDPPC) has been measured. Conformational search through relaxed scan has been carried out to find the most stable conformational isomer. After the full geometry optimization for the most stable conformer using B3LYP and BLYP hybrid functionals of Density Functional Theory (DFT), vibrational normal modes have been calculated at the same theoretical levels. Potential Energy Distribution (PED) of each normal mode has been calculated by means of VEDA4 to obtain contributions of internal coordinates to the normal modes. Natural Bond Orbital (NBO) analysis has been performed to get insights into the possible hydrogen bonding sites for all the conformational isomers.

  18. Hydrogen peroxide deposition and decomposition in rain and dew waters

    Science.gov (United States)

    Ortiz, Vicky; Angélica Rubio, M.; Lissi, Eduardo A.

    Peroxides and hydrogen peroxide were determined by a fluorometric method in dew and rain collected in the atmosphere of Santiago of Chile city. The measured peroxides comprise hydrogen peroxide (the main component) and peroxides not decomposed by catalase. The collected natural peroxides readily decompose in the natural matrix, rendering difficult an estimation of the values present in real-time. In order to establish the kinetics of the process and the factors that condition their decomposition, the kinetics of the decay at several pHs and/or the presence of metal chelators were followed. The kinetics of hydrogen peroxide decomposition in the water matrix was evaluated employing the natural peroxides or hydrogen peroxide externally added. First-order kinetics was followed, with half decay times ranging from 80 to 2300 min. The addition of Fe(II) in the micromolar range increases the decomposition rate, while lowering the pH (<3) notably reduces the rate of the process. The contribution of metals to the decomposition of the peroxides in the natural waters was confirmed by the reduction in decomposition rate elicited by its treatment with Chelex-100. Dew and rain waters were collected in pre-acidified collectors, rendering values considerably higher than those measured in non-treated collectors. This indicates that acidification can be proposed as an easy procedure to stabilize the samples, reducing its decomposition during collection time and the time elapsed between collection and analysis. The weighted average concentration for total peroxides measured in pre-treated collectors was 5.4 μM in rains and 2.2 μM in dews.

  19. Ultrasound-assisted phase-transfer catalysis: benzoylation of sodium 4-acetylphenoxide by dual-site phase-transfer catalyst in a tri-liquid system.

    Science.gov (United States)

    Yang, Hung-Ming; Chiu, Chun-Cheng

    2011-01-01

    A novel dual-site phase-transfer catalyst (PTC) was prepared and used to conduct the benzoylation of sodium 4-acetylphenoxide by ultrasound-assisted third-liquid phase-transfer catalysis. The catalyst 1,4-bis(tributylammoniomethyl)benzene dibromide (BTBAMBB) was synthesized from the reaction of p-xylylene dibromide and tributylamine in toluene at 70°C. The dual-site PTC was employed to form the third-liquid phase by extra addition of 0.04-0.05 mol of NaCl into 10 cm(3) of water. In the condition of 0.0425 mol of NaCl at 30°C, the catalytic intermediate in the third-liquid phase reached a maximum value. Almost 80% of the catalyst was transferred from the aqueous phase into the third-liquid phase. The distributions of the catalytic intermediate and dual-site PTC between phases and the kinetics of benzoylation of sodium 4-acetylphenoxide catalyzed by BTBAMBB with ultrasound irradiation were performed. The pseudo-first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (28 kHz/300 W) in a batch reactor, the yield of product 4-acetylphenyl benzoate in the organic phase was 98.1% in 2 min at 30°C and 250 rpm with the apparent rate constant k(app) to be 0.0075 s(-1), which was 6 times faster than that without using ultrasound (yield=14.4%, k(app)=0.0013 s(-1)). The present study provides a green method to synthesize esters by ultrasound-assisted third-liquid phase-transfer catalysis.

  20. Studies on Synthesis of Some Novel Heterocyclic Chalcone, Pyrazoline, Pyrimidine - 2 - One, Pyrimidine - 2 - Thione, para-Acetanilide Sulphonyl and Benzoyl Derivatives and their Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Rakesh N. Mistry

    2005-01-01

    Full Text Available 1, 2 - Dichloro benzene on chlorosulphonation by chlorosulphonic acid gives 1, 2 - [dichloro] - benzene sulphonyl chloride which on condensation with p –amino acetophenone gives 1-[acetyl] - 1’ , 2’ - [dichloro] - dibenz sulphonamide derivative. This derivative undergo condensation with 2,4- dichloro benzaldehyde gives 1- [3” - (sub. phenyl - 2” - propene - 1” - one] - 1’ , 2’ - [dichloro] - dibenz sulphonamide derivative which on reaction with 99% hydrazine hydrate and glacial acetic acid gives 1-[acetyl]-3- [1’ , 2’ - (dichloro - dibenz sulphonamide] -5 - [2” , 4” - dichloro phenyl] - 2 - pyrazoline derivative. This derivative reacts with various substituted aldehydes to give corresponding substituted chalcone derivatives [1(a-j]. Now, these chalcone derivatives [1(a-j] on condensation with urea gives corresponding substituted pyrimidine - 2 - one derivatives [2(a-j] and on condensation with thio-urea gives corresponding substituted pyrimidine- 2 -thione derivatives [3(a-j]. Further, these chalcone derivatives [1(a-j] on reaction with 99% hydrazine hydrate gives 1 - [1’ - (H - 5’ - (sub. phenyl - 2’ - pyrazoline]- 3 - [1” , 2” - (dichloro - dibenz sulphonamide] - 5 - [2’’’ , 4’’’ - dichloro phenyl]-2- pyrazoline derivatives [4(a-j] as an intermediate compounds, which on condensation with p-acetanilide sulphonyl chloride gives corresponding substituted p - acetanilide sulphonyl derivatives [5(a-j] and on condensation with benzoyl chloride gives corresponding substituted benzoyl derivatives [6(a-j]. Structure elucidation of synthesised compounds has been made on the basis of elemental analysis, I.R. spectral studies and 1H N.M.R. spectral studies. The antimicrobial activity of the synthesised compounds has been studied against the cultures “Staphylococcus aureus”, “Escherichia coli” and “Candela albicans”.

  1. [Lipid peroxidation in the adrenal cortex during exhausting stress].

    Science.gov (United States)

    Doroshkevich, N A; Antsulevich, S N; Naumov, A V; Vinogradov, V V

    1990-05-01

    Under prolonged stress which is connected with exhaustion of functional resources of adrenal cortex the activation of lipid peroxidation processes in this gland was found. It is possible that the reason for such lipid peroxidation activation is the decrease in the content of adrenal cortex ascorbic acid and alpha-tocopherol.

  2. A hydrogen peroxide sensor for exhaled breath measurement

    NARCIS (Netherlands)

    Anh, Dam T.V.; Olthuis, W.; Bergveld, P.; Berg, van den A.

    2004-01-01

    An increase in produced hydrogen peroxide concentration in exhaled breath (EB) of patients, who suffer from some diseases related to lung function, has been observed and considered as a reliable indicator of lung diseases. In the EB of these patients, hydrogen peroxide is present in the vapour phase

  3. A hydrogen peroxide sensor for exhaled breath measurement

    NARCIS (Netherlands)

    Anh, Dam Thi Van; Olthuis, W.; Bergveld, P.

    2005-01-01

    An increase in hydrogen peroxide concentration in exhaled breath (EB) of patients, who suffer from some diseases related to the lung function, has been observed and considered as a reliable indicator of lung diseases. In the EB of these patients, hydrogen peroxide is present in the vapour phase toge

  4. Hydrogen peroxide decomposition kinetics in aquaculture water

    DEFF Research Database (Denmark)

    Arvin, Erik; Pedersen, Lars-Flemming

    2015-01-01

    Hydrogen peroxide (HP) is used in aquaculture systems where preventive or curative water treatments occasionally are required. Use of chemical agents can be challenging in recirculating aquaculture systems (RAS) due to extended water retention time and because the agents must not damage the fish...... reared or the nitrifying bacteria in the biofilters at concentrations required to eliminating pathogens. This calls for quantitative insight into the fate of the disinfectant residuals during water treatment. This paper presents a kinetic model that describes the HP decomposition in aquaculture water...... the enzyme activity. This was, however, not measured. The model developed successfully described the removal of HP in aquaculture water from three types of RAS and model parameters are estimated. The model and the model parameters provide new information and are valuable tools to improve HP application...

  5. Hydrogen Peroxide Storage in Small Sealed Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J.

    1999-10-20

    Unstabilized hydrogen peroxide of 85% concentration has been prepared in laboratory quantities for testing material compatibility and long term storage on a small scale. Vessels made of candidate tank and liner materials ranged in volume from 1 cc to 2540 cc. Numerous metals and plastics were tried at the smallest scales, while promising ones were used to fabricate larger vessels and liners. An aluminum alloy (6061-T6) performed poorly, including increasing homogeneous decay due to alloying elements entering solution. The decay rate in this high strength aluminum was greatly reduced by anodizing. Better results were obtained with polymers, particularly polyvinylidene fluoride. Data reported herein include ullage pressures as a function of time with changing decay rates, and contamination analysis results.

  6. Locating bomb factories by detecting hydrogen peroxide.

    Science.gov (United States)

    Romolo, Francesco Saverio; Connell, Samantha; Ferrari, Carlotta; Suarez, Guillaume; Sauvain, Jean-Jacques; Hopf, Nancy B

    2016-11-01

    The analytical capability to detect hydrogen peroxide vapour can play a key role in localizing a site where a H2O2 based Improvised Explosive (IE) is manufactured. In security activities it is very important to obtain information in a short time. For this reason, an analytical method to be used in security activity needs portable devices. The authors have developed the first analytical method based on a portable luminometer, specifically designed and validated to locate IE manufacturing sites using quantitative on-site vapour analysis for H2O2. The method was tested both indoor and outdoor. The results demonstrate that the detection of H2O2 vapours could allow police forces to locate the site, while terrorists are preparing an attack. The collected data are also very important in developing new sensors, able to give an early alarm if located at a proper distance from a site where an H2O2 based IE is prepared.

  7. Unusual hydrogen peroxide decomposition on stoichiometric insulating oxide ultrathin films

    CERN Document Server

    Song, Zhenjun

    2016-01-01

    The hydrogen peroxide dissociation on MgO(001) films deposited on Mo(001) surface is investigated by employing periodic density-functional theory methods. The pristine MgO(001) surface showing chemical inertness prefers the weak adsorbing molecular configuration and is extremely difficult to react with hydrogen peroxide. As far as we know, energetically favorable decomposition state of hydrogen peroxide has never been obtained on MgO(001) surface. In this work the hydrogen peroxide is successfully dissociated on perfect stoichiometric MgO(001) films by depositing on transition metal substrate, without any activation barrier. The spontaneous dissociation of hydrogen peroxide on metal supported oxide films is rationalized by characterizing the geometric structures and electronic structures.

  8. Durability of bleaching results achieved with 15% carbamide peroxide and 38% hydrogen peroxide in vitro.

    Science.gov (United States)

    Knösel, Michael; Reus, Monika; Rosenberger, Albert; Attin, Thomas; Ziebolz, Dirk

    2011-01-01

    The aim of this study was to assess the durability of bleaching results achieved with (1) 15% carbamide peroxide home bleaching and (2) 38% hydrogen peroxide in-office bleaching. A total of 231 extracted anterior teeth were randomly divided into three groups (n = 77 in each group) with comparable mean baseline L*-values (68.24 ± 0.8): a non-bleached control group A, a 15% carbamide peroxide group B (5 bleaching intervals of 8 hours), and a 38% hydrogen peroxide group C (3 intervals of 15 minutes). Durability of bleaching was assessed by comparing CIE-L*a*b* data after intervals of 2, 4, 12, and 26 weeks from baseline. Both bleaching regimes initially produced a highly significant increase in lightness parameter L*, with no significant difference between the respective bleaching regimes (B: 68.23 / 72.48; C: 68.32 / 73.25). Six months after starting the trial, L*-values for group B yielded no significant differences compared to baseline (69.55), whereas L*-values for group C were still significantly raised (69.91), despite a highly significant decrease when compared to initial bleaching results. In both treatment groups, there was a lasting response to bleaching in terms of CIE-a* and -b* value decreases. Results for both home- and in-practice regimes were found to be similar for about 12 weeks. However, in-office results were longer lasting, despite the shorter treatment intervals. Summarized bleaching effects, in terms of delta E values, revealed no significant differences between treatment groups and the control group after 6 months, indicating an abatement of the bleaching results achieved.

  9. PEROXIDE DESTRUCTION TESTING FOR THE 200 AREA EFFLUENT TREATMENT FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    HALGREN DL

    2010-03-12

    The hydrogen peroxide decomposer columns at the 200 Area Effluent Treatment Facility (ETF) have been taken out of service due to ongoing problems with particulate fines and poor destruction performance from the granular activated carbon (GAC) used in the columns. An alternative search was initiated and led to bench scale testing and then pilot scale testing. Based on the bench scale testing three manganese dioxide based catalysts were evaluated in the peroxide destruction pilot column installed at the 300 Area Treated Effluent Disposal Facility. The ten inch diameter, nine foot tall, clear polyvinyl chloride (PVC) column allowed for the same six foot catalyst bed depth as is in the existing ETF system. The flow rate to the column was controlled to evaluate the performance at the same superficial velocity (gpm/ft{sup 2}) as the full scale design flow and normal process flow. Each catalyst was evaluated on peroxide destruction performance and particulate fines capacity and carryover. Peroxide destruction was measured by hydrogen peroxide concentration analysis of samples taken before and after the column. The presence of fines in the column headspace and the discharge from carryover was generally assessed by visual observation. All three catalysts met the peroxide destruction criteria by achieving hydrogen peroxide discharge concentrations of less than 0.5 mg/L at the design flow with inlet peroxide concentrations greater than 100 mg/L. The Sud-Chemie T-2525 catalyst was markedly better in the minimization of fines and particle carryover. It is anticipated the T-2525 can be installed as a direct replacement for the GAC in the peroxide decomposer columns. Based on the results of the peroxide method development work the recommendation is to purchase the T-2525 catalyst and initially load one of the ETF decomposer columns for full scale testing.

  10. A protocol to generate phthaloyl peroxide in flow for the hydroxylation of arenes.

    Science.gov (United States)

    Eliasen, Anders M; Thedford, Randal P; Claussen, Karin R; Yuan, Changxia; Siegel, Dionicio

    2014-07-18

    A flow protocol for the generation of phthaloyl peroxide has been developed. This process directly yields phthaloyl peroxide in high purity (>95%) and can be used to bypass the need to isolate and recrystallize phthaloyl peroxide, improving upon earlier batch procedures. The flow protocol for the formation of phthaloyl peroxide can be combined with arene hydroxylation reactions and provides a method for the consumption of peroxide as it is generated to minimize the accumulation of large quantities of peroxide.

  11. Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

    Directory of Open Access Journals (Sweden)

    Alexander O. Terent'ev

    2014-01-01

    Full Text Available The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides, 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update on synthesis of cyclic peroxides. The indicated period of time is, on the whole, characterized by the development of new efficient and scale-up methods for the preparation of these cyclic compounds. It was shown that cyclic peroxides remain unchanged throughout the course of a wide range of fundamental organic reactions. Due to these properties, the molecular structures can be greatly modified to give peroxide ring-retaining products. The chemistry of cyclic peroxides has attracted considerable attention, because these compounds are used in medicine for the design of antimalarial, antihelminthic, and antitumor agents.

  12. Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

    Science.gov (United States)

    Borisov, Dmitry A; Vil’, Vera A; Dembitsky, Valery M

    2014-01-01

    Summary The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides), 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update on synthesis of cyclic peroxides. The indicated period of time is, on the whole, characterized by the development of new efficient and scale-up methods for the preparation of these cyclic compounds. It was shown that cyclic peroxides remain unchanged throughout the course of a wide range of fundamental organic reactions. Due to these properties, the molecular structures can be greatly modified to give peroxide ring-retaining products. The chemistry of cyclic peroxides has attracted considerable attention, because these compounds are used in medicine for the design of antimalarial, antihelminthic, and antitumor agents. PMID:24454562

  13. Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products.

    Science.gov (United States)

    Terent'ev, Alexander O; Borisov, Dmitry A; Vil', Vera A; Dembitsky, Valery M

    2014-01-08

    The present review describes the current status of synthetic five and six-membered cyclic peroxides such as 1,2-dioxolanes, 1,2,4-trioxolanes (ozonides), 1,2-dioxanes, 1,2-dioxenes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes. The literature from 2000 onwards is surveyed to provide an update on synthesis of cyclic peroxides. The indicated period of time is, on the whole, characterized by the development of new efficient and scale-up methods for the preparation of these cyclic compounds. It was shown that cyclic peroxides remain unchanged throughout the course of a wide range of fundamental organic reactions. Due to these properties, the molecular structures can be greatly modified to give peroxide ring-retaining products. The chemistry of cyclic peroxides has attracted considerable attention, because these compounds are used in medicine for the design of antimalarial, antihelminthic, and antitumor agents.

  14. Quantification of peroxide ion passage in dentin, enamel, and cementum after internal bleaching with hydrogen peroxide.

    Science.gov (United States)

    Palo, R M; Bonetti-Filho, I; Valera, M C; Camargo, C H R; Camargo, Sea; Moura-Netto, C; Pameijer, C

    2012-01-01

    The aim of this study was to evaluate the amount of peroxide passage from the pulp chamber to the external enamel surface during the internal bleaching technique. Fifty bovine teeth were sectioned transversally 5 mm below the cemento-enamel junction (CEJ), and the remaining part of the root was sealed with a 2-mm layer of glass ionomer cement. The external surface of the samples was coated with nail varnish, with the exception of standardized circular areas (6-mm diameter) located on the enamel, exposed dentin, or cementum surface of the tooth. The teeth were divided into three experimental groups according to exposed areas close to the CEJ and into two control groups (n=10/group), as follows: GE, enamel exposure area; GC, cementum exposed area; GD, dentin exposed area; Negative control, no presence of internal bleaching agent and uncoated surface; and Positive control, pulp chamber filled with bleaching agent and external surface totally coated with nail varnish. The pulp chamber was filled with 35% hydrogen peroxide (Opalescence Endo, Ultradent). Each sample was placed inside of individual flasks with 1000 μL of acetate buffer solution, 2 M (pH 4.5). After seven days, the buffer solution was transferred to a glass tube, in which 100 μL of leuco-crystal violet and 50 μL of horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to Kruskal-Wallis and Dunn-Bonferroni tests (α=0.05). All experimental groups presented passage of peroxide to the external surface that was statistically different from that observed in the control groups. It was verified that the passage of peroxide was higher in GD than in GE (pperoxide passage than did GD and GE (pperoxide placed into the pulp chamber passed through the dental hard tissues, reaching the external surface and the periodontal tissue. The cementum surface

  15. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  16. Effect of Ascorbic Acid on Lipid Peroxidation Induced by Ceftazidime

    Directory of Open Access Journals (Sweden)

    Devbhuti P*,1

    2011-01-01

    Full Text Available Lipid peroxidation is the oxidative deterioration of polyunsaturated lipids which is a free radical related process and responsible for thedevelopment of many diseases and disorders like diabetes mellitus, hypertension, cancer etc. End products of lipid peroxidation aremalondialdehyde (MDA, 4-hydroxy-2-nonenal (4-HNE, etc. which are the ultimate mediator of toxicity. Antioxidants have the capability toinhibit lipid peroxidation. Keeping in mind this fact, the present in vitro study was carried out to evaluate lipid peroxidation induction potential of ceftazidime, a cephalosporin antibiotic and its suppression with ascorbic acid considering some laboratory markers of lipid peroxidation like MDA, 4-HNE and reduced glutathione (GSH. Goat liver was used as the lipid source. After treatment of the liver homogenate with drug and/or antioxidant the levels of 4-HNE, MDA and GSH were estimated in different samples at different hours of incubation. The results showed that the drug ceftazidime could significantly induce lipid peroxidation and the antioxidant ascorbic acid has the capability to inhibit ceftazidime-inducedlipid peroxidation.

  17. Peroxide cross-linked UHMWPE blended with vitamin E.

    Science.gov (United States)

    Oral, Ebru; Doshi, Brinda N; Gul, Rizwan M; Neils, Andrew L; Kayandan, Sanem; Muratoglu, Orhun K

    2016-04-15

    Radiation crosslinked ultrahigh molecular weight polyethylene (UHMWPE) is the bearing surface material most commonly used in total joint arthroplasty because of its excellent wear resistance. Crosslinking agents such as peroxides can also effectively increase wear resistance but peroxide crosslinked UHMWPE has low oxidative stability. We hypothesized that the addition of an antioxidant to peroxide crosslinked UHMWPE could improve its oxidation resistance and result in mechanical, tribological, and oxidative properties equivalent to currently utilized radiation crosslinked UHMWPEs. Various vitamin E (0.1-1.0 wt % and peroxide concentration (0.5-1.5 wt %) combinations were studied to investigate changes in crosslink density, wear rate, mechanical properties, and oxidative stability in comparison to radiation crosslinked UHMWPE. Peroxide crosslinking was more efficient as compared to radiation crosslinking in the presence of vitamin E with the former resulting in lower wear rate with vitamin E concentrations above 0.3 wt %. The tensile mechanical properties were comparable to and the impact strength was higher than those of the clinically relevant radiation crosslinked controls. We also determined that gamma sterilization of peroxide crosslinked vitamin E blends improved wear resistance further. In summary, peroxide crosslinking of vitamin E-blended UHMWPE may provide a feasible and economical alternative to radiation for achieving clinically relevant properties for total joint implants using UHMWPE. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  18. Dissolution of spent nuclear fuel in carbonate-peroxide solution

    Science.gov (United States)

    Soderquist, Chuck; Hanson, Brady

    2010-01-01

    This study shows that spent UO2 fuel can be completely dissolved in a room temperature carbonate-peroxide solution apparently without attacking the metallic Mo-Tc-Ru-Rh-Pd fission product phase. In parallel tests, identical samples of spent nuclear fuel were dissolved in nitric acid and in an ammonium carbonate, hydrogen peroxide solution. The resulting solutions were analyzed for strontium-90, technetium-99, cesium-137, europium-154, plutonium, and americium-241. The results were identical for all analytes except technetium, where the carbonate-peroxide dissolution had only about 25% of the technetium that the nitric acid dissolution had.

  19. KINETICS OF NEUTRAL HYDROLYSIS OF 1-BENZOYL-3-PHENYL-1,2,4-TRIAZOLE IN HIGHLY AQUEOUS-MEDIA - ANALYSIS OF EFFECTS OF ADDED ETHANOL AND PROPAN-1-OL IN TERMS OF PAIRWISE GROUP-INTERACTION PARAMETERS

    NARCIS (Netherlands)

    BENAK, H; ENGBERTS, JBFN; BLANDAMER, MJ

    1992-01-01

    Over the range 288.15 less-than-or-equal-to T/K less-than-or-equal-to 333.15, the first-order rate constant for the neutral hydrolysis of 1-benzoyl-3-phenyl-1,2,4-triazole in aqueous solutions (pH ca. 4) decreases when either ethanol or propan-1-ol is added. The kinetic data are analysed in terms of

  20. Distribution of Gaseous and Particulate Organic Peroxides Formed in the Ozonolysis of α-Pinene

    Science.gov (United States)

    Li, H.; Chen, Z.; Huang, L.; Huang, D.

    2015-12-01

    Organic peroxides, an important species in the atmosphere, will affect HOx cycling, promote SOA aging, and cause adverse health effect. However, the formation, distribution and evolution of organic peroxides are extremely complicated and still unclear. In this study, we investigate in laboratory the production of peroxides and gas-particle partitioning in the ozonolysis of α-pinene. The molar yields of hydrogen peroxide (H2O2), hydromethyl hydroperoxide (HMHP), performic acid (PFA), peracetic acid (PAA) and total peroxides (TPO, including unknown peroxides) and contribution of peroxides to SOA mass are carefully determined. Comparing the gaseous and particulate peroxides, we find that more than 75% peroxides formed in the ozonolysis remain in the gas phase, and water vapour will significantly influence the formation and distribution of peroxides. Such an unexpected large amount of gaseous peroxides deserves more attention, especially to their effect on HOx cycling.

  1. Stable magnesium peroxide at high pressure.

    Science.gov (United States)

    Lobanov, Sergey S; Zhu, Qiang; Holtgrewe, Nicholas; Prescher, Clemens; Prakapenka, Vitali B; Oganov, Artem R; Goncharov, Alexander F

    2015-09-01

    Rocky planets are thought to comprise compounds of Mg and O as these are among the most abundant elements, but knowledge of their stable phases may be incomplete. MgO is known to be remarkably stable to very high pressure and chemically inert under reduced condition of the Earth's lower mantle. However, in exoplanets oxygen may be a more abundant constituent. Here, using synchrotron x-ray diffraction in laser-heated diamond anvil cells, we show that MgO and oxygen react at pressures above 96 GPa and T = 2150 K with the formation of I4/mcm MgO2. Raman spectroscopy detects the presence of a peroxide ion (O2(2-)) in the synthesized material as well as in the recovered specimen. Likewise, energy-dispersive x-ray spectroscopy confirms that the recovered sample has higher oxygen content than pure MgO. Our finding suggests that MgO2 may be present together or instead of MgO in rocky mantles and rocky planetary cores under highly oxidized conditions.

  2. Stable magnesium peroxide at high pressure

    Science.gov (United States)

    Lobanov, Sergey S.; Zhu, Qiang; Holtgrewe, Nicholas; Prescher, Clemens; Prakapenka, Vitali B.; Oganov, Artem R.; Goncharov, Alexander F.

    2015-09-01

    Rocky planets are thought to comprise compounds of Mg and O as these are among the most abundant elements, but knowledge of their stable phases may be incomplete. MgO is known to be remarkably stable to very high pressure and chemically inert under reduced condition of the Earth’s lower mantle. However, in exoplanets oxygen may be a more abundant constituent. Here, using synchrotron x-ray diffraction in laser-heated diamond anvil cells, we show that MgO and oxygen react at pressures above 96 GPa and T = 2150 K with the formation of I4/mcm MgO2. Raman spectroscopy detects the presence of a peroxide ion (O22-) in the synthesized material as well as in the recovered specimen. Likewise, energy-dispersive x-ray spectroscopy confirms that the recovered sample has higher oxygen content than pure MgO. Our finding suggests that MgO2 may be present together or instead of MgO in rocky mantles and rocky planetary cores under highly oxidized conditions.

  3. Characterization and heterologous expression of hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/benzoyltransferase from elicited cell cultures of carnation, Dianthus caryophyllus L.

    Science.gov (United States)

    Yang, Q; Reinhard, K; Schiltz, E; Matern, U

    1997-12-01

    Benzoyl-CoA:anthranilate N-benzoyltransferase catalyzes the first committed reaction of phytoalexin biosynthesis in carnation (Dianthus caryophyllus L.), and the product N-benzoylanthranilate is the precursor of several sets of dianthramides. The transferase activity is constitutively expressed in suspension-cultured carnation cells and can be rapidly induced by the addition of yeast extract. The enzyme was purified to homogeneity from yeast-induced carnation cells and shown to consist of a single polypeptide chain of 53 kDa. Roughly 20% of the sequence was identified by micro-sequencing of tryptic peptides, and some of these sequences differed in a few amino acid residues only suggesting the presence of isoenzymes. A specific 0.8 kb cDNA probe was generated by RT-PCR, employing degenerated oligonucleotide primers complementary to two of the tryptic peptides and using poly(A)+ RNA from elicited carnation cells. Five distinct benzoyltransferase clones were isolated from a cDNA library, and three cDNAs, pchcbt1-3, were sequenced and shown to encode full-size N-benzoyltransferases. The translated peptide sequences revealed more than 95% identity among these three clones. The additional two clones harbored insert sequences mostly homologous with pchcbt 1 but differing in the 3'-flanking regions due to variable usage of poly(A) addition sites. The identity of the clones was confirmed by matching the translated polypeptides with the tryptic enzyme sequences as well as by the activity of the benzoyltransferase expressed in Escherichia coli. Therefore, carnation encodes a small family of anthranilate N-benzoyltransferase genes. In vitro, the benzoyltransferases exhibited narrow substrate specificity for anthranilate but accepted a variety of aromatic acyl-CoAs. Catalytic rates with cinnamoyl- or 4-coumaroyl-CoA exceeded those observed with benzoyl-CoA, although the corresponding dianthramides did not accumulate in vivo. Thus the cDNAs described represent also the first

  4. Lab-scale hydrogen peroxide data from ECBC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data from small lab scale tests conducted at ECBC. It contains efficacy data as well as data on env conditions such as temperature, RH, and hydrogen peroxide vapor...

  5. Hydrogen peroxide in breath condensate during a common cold

    Directory of Open Access Journals (Sweden)

    Rijn Q. Jöbsis

    2001-01-01

    Full Text Available Background: Hydrogen peroxide (H2O2 in exhaled air condensate is elevated in inflammatory disorders of the lower respiratory tract. It is unknown whether viral colds contribute to exhaled H2O2.

  6. A Novel Fluorescent Reagent for Analysis of Hydrogen Peroxide

    Institute of Scientific and Technical Information of China (English)

    董素英; 苏美红; 聂丽华; 马会民

    2003-01-01

    8-(4,6-Dichloro-1,3,5-trazinoxy)quinoline(DTQ) was evaluated as a new fluorescent reagent for determining hydrogen peroxide.It was found that the fluorescence intensity of DTQ in alkaline medium could be dramatically enhanced upon addition of H2O2.Based on this effect,a simple and selective method for the spectrofluorimetric determination of hydrogen peroxide was estabhlished.The relative standard deviation of the method was found to be 1.1?for 9 replicate determinations of a 4.6×10-6mol/L hydrogen peroxide solution.The linear range was 2.3×10-7-2.3×10-5mol/L with a detection limit of 2.2×10-8mol/L(S/N=3).The ,method was attempted to determine hydrogen peroxide in synthetic human serum samples with satisfactory results.

  7. High Test Peroxide High Sealing Conical Seal Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High Test Peroxide (HTP) Highly Compatible High Sealing Conical Seals are necessary for ground test operations and space based applications. Current conical seals...

  8. [Risks of hydrogen peroxide irrigation in military surgery].

    Science.gov (United States)

    Saïssy, J M; Guignard, B; Pats, B; Lenoir, B; Rouvier, B

    1994-01-01

    Two cases of severe complications due to injection of hydrogen peroxide under pressure into areas of muscular attrition in war wounds are reported. In both cases the administration of hydrogen peroxide was associated with tachypnoea, with major arterial desaturation and a precordial "mill-wheel" murmur was heard. In one case, these symptoms were followed by hemiplegia caused by paradoxical arterial gas embolism, and in the other case by a pulmonary oedema confirmed by computerized tomography. Both patients recovered under hyperbaric oxygen therapy. The release of gaseous oxygen under the effect of tissue catalase and the membrane peroxydasic activity of hydrogen peroxide initiate such complications. The injection of hydrogen peroxide under pressure into a closed or partially closed cavity should therefore be strictly prohibited.

  9. Efficient Electrochemical Hydrogen Peroxide Generation in Water Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An electrochemical cell is proposed for the efficient generation of 3% hydrogen peroxide (H2O2) in pure water using only power, oxygen and water. H2O2 is an...

  10. Alkene dihydroxylation with malonoyl peroxides: catalysis using fluorinated alcohols.

    Science.gov (United States)

    Picon, Sylvain; Rawling, Michael; Campbell, Matthew; Tomkinson, Nicholas C O

    2012-12-21

    The effect of fluorinated alcohols on the dihydroxylation of alkenes using cyclopropyl malonoyl peroxide is described. Addition of perfluoro-tert-butyl alcohol to a toluene solution of alkene and peroxide increases the rate of product formation and the stereoselectivity observed, providing a simple and effective method for acceleration of this important class of reaction. Basic hydrolysis of the crude reaction mixture provides access to syn-diols in high yield and stereoselectivity.

  11. An improved method for the quantification of SOA bound peroxides

    Science.gov (United States)

    Mutzel, Anke; Rodigast, Maria; Iinuma, Yoshiteru; Böge, Olaf; Herrmann, Hartmut

    2013-03-01

    An improvement is made to a method for the quantification of SOA-bound peroxides. The procedure is based on an iodometric-spectrophotometric method that has been commonly used for the determination of peroxides in a wide range of biological and environmental samples. The improved method was applied to determine the peroxide content of laboratory-generated SOA from α-pinene ozonolysis. Besides main improvements for the detection conditions, the use of more environmentally sound solvents is considered instead of carcinogenic solvents. In addition to the improved method for peroxide determination, the present study provides evidence for artefact formation caused by ultrasonic agitation for the extraction of organic compounds in SOA filter samples. The concentration of SOA-bound peroxides in the extracts from ultrasonic agitation were up to three times higher than those from a laboratory orbital shaker under the same extraction conditions, indicating peroxide formation caused by acoustic cavitation during extraction. In contrast, pinic acid, terebic acid and terpenylic acid showed significantly lower concentrations in the sample extract prepared using ultrasonic agitation, indicating that these compounds react with OH radicals that are formed from acoustic cavitation. Great care should be taken when extracting SOA samples and the use of ultrasound should be avoided.

  12. Recent Development in Hydrogen Peroxide Pumped Propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A G; Antelman, D R; Dobie, D W; Gorman, T S; Jones, M S; Kordas, J F; McMahon, D H; Ng, L C; Nielsen, D P; Ormsby, A E; Pittenger, L C; Robinson, J A; Skulina, K M; Taylor, W G; Urone, D A; Wilson, B A

    2004-03-22

    This paper describes the development of a lightweight high performance pump-fed divert and attitude control system (DACS). Increased kinetic Kill Vehicles (KV) capabilities (higher .v and acceleration capability) will especially be needed for boost phase engagements where a lower mass KV DACS enables smaller overall interceptors. To increase KV performance while reducing the total DACS dry mass (<10 kg), requires a design approach that more closely emulates those found in large launch vehicles, where pump-fed propulsion enables high propellant-mass-fraction systems. Miniaturized reciprocating pumps, on a scale compatible with KV applications, offer the potential of a lightweight DACS with both high {Delta}v and acceleration capability, while still enabling the rapid pulsing of the divert thrusters needed in the end-game fly-in. Pumped propulsion uses lightweight low-pressure propellant tanks, as the main vehicle structure and eliminates the need for high-pressure gas bottles, reducing mass and increasing the relative propellant load. Prior work used hydrazine and demonstrated a propellant mass fraction >0.8 and a vehicle propulsion dry mass of {approx}3 kg. Our current approach uses the non-toxic propellants 90% hydrogen peroxide and kerosene. This approach enables faster development at lower costs due to the ease of handling. In operational systems these non-toxic propellants can simplify the logistics for manned environments including shipboard applications. This DACS design configuration is expected to achieve sufficient mass flows to support divert thrusters in the 1200 N to 1330 N (270 lbf to 300 lbf) range. The DACS design incorporates two pairs of reciprocating differential piston pumps (oxidizer and fuel), a warm-gas drive system, compatible bi-propellant thrusters, lightweight valves, and lightweight low-pressure propellant tanks. This paper summarizes the current development status and plans.

  13. Synthesis, Characterization and Antimicrobial Activity of Potassium Hydro(benzoyl)(phthalyl)borate and Its Cobalt(Ⅱ), Nickel(Ⅱ), and Copper(Ⅱ) Complexes

    Institute of Scientific and Technical Information of China (English)

    SHARMA, Guruaribam, Shashikumar; SHEIKH, Rayees, Ahmad; SHREAZ, Sheikh; HASHMI, Athar, Adil; KHAN, Luqrnan, Ahmad

    2009-01-01

    A new organoborate ligand, hydro(benzoyl)(phthalyl)borate has been synthesized as its potassium salt (KL) and M=Cu(Ⅱ)]. All compounds were characterized by elemental analysis, DTIR, 1H NMR, ESI MS, UV-Vis techniques, conductivity and magnetic data measurements. Spectroscopic results suggest a square planar geometry in the Cu(Ⅱ) complex, while the Co(Ⅱ) and Ni(Ⅱ) complexes possess an octahedral geometry. Antibacterial activities (in vitro) of the ligand and its metal complexes were studied against two Gram positive (B. subtillis and B. magterium) and two Gram negative bacteria (E. Coli and S. boydi) at a single concentration (75 μg/mL) by using the Disc diffusion method. Antifungal activities (in vitro) were also checked for the compounds by using the same method against Candida albicans 10261, Penicillium sp. and Asperjillius niger., at a single concentration (50 μg/mL). The results showed that all the metal complexes, specially the nickel(Ⅱ) complex, have higher antibacterial and antifungal ac- tivities than the corresponding potassium salt.

  14. 5-Benzoyl-2-(5-bromo-1H-indol-3-yl-4-(4-methoxyphenyl-1H-pyrrole-3-carbonitrile

    Directory of Open Access Journals (Sweden)

    G. Vimala

    2016-05-01

    Full Text Available In the title compound, C27H18BrN3O, the indole and central pyrrole ring systems are inclined to one another by 13.15 (15°. The carbonitrile group is almost coplanar with its attached pyrrole ring, the C[triple-bond]N bond making a dihedral angle of 1.9 (2° with the ring plane. The 4-methoxybenzene ring and the benzoyl ring are inclined to the central pyrrole ring by 55.1 (2 and 51.5 (2°, respectively. The dihedral angle between these two benzene rings is 37.68 (17°. In the crystal, molecules are linked by pairs of N—H...N hydrogen bonds, forming inversion dimers with an R22(16 ring motif. The dimers are linked by offset π–π interactions [intercentroid distance = 3.614 (2 Å], which leads to the formation of chains propagating in the [010] direction.

  15. Synthesis and anticancer activity evaluation of new 2-alkylcarbonyl and 2-benzoyl-3-trifluoromethyl-quinoxaline 1,4-di-N-oxide derivatives.

    Science.gov (United States)

    Zarranz, Belén; Jaso, Andrés; Aldana, Ignacio; Monge, Antonio

    2004-07-01

    As a continuation of our research in quinoxaline 1,4-di-N-oxide and with the aim of obtaining new anticancer agents, which can improve the current chemotherapeutic treatments, new series of 2-alkylcarbonyl and 2-benzoyl-3-trifluoromethylquinoxaline 1,4-di-N-oxide derivatives have been synthesized and evaluated for in vitro antitumor activity against a 3-cell line panel, consisting of MCF7 (breast), NCI-H460 (lung), and SF-268 (CNS). These active compounds were then evaluated in the full panel of 60 human tumor cell lines derived from nine cancer cell types. The results have shown that, in general, anticancer activity depends on the substituents in the carbonyl group, improving in the order: ethyl

  16. Interaction Study of 2,6-Bis[4-(4-amino-2-trifluoromethyl phenoxy)benzoyl] Pyridine with Human Immunoglobulin by Optical Spectroscopy and Molecular Modeling

    Institute of Scientific and Technical Information of China (English)

    HE Wenying; ZHANG Qiongmei; GAO Wenhua; DONG Yuming; YAO Xiaojun

    2009-01-01

    The interaction between human immunoglobulin (HIgG) and BAFP (2,6-bis[4-(4-amino-2-trifluoromethyl phenoxy)benzoyl] pyridine was studied by fluorescence quenching, Fourier transform infrared (FT-IR) spectra and molecule modeling. The synchronous fluorescence spectra indicated the information on qualitative changes of the pro-tein secondary structure in the presence of BAFP in aqueous solution. The quantitative alterations of the protein sec-ondary structure were estimated by the evidences from FT-IR spectra with increases of α helices by about 2.6%-10.2%, increases of β-sheet structure by about 13.6%-27.7%, and reductions of β-turn structure by about 23.8%-30.3%. Molecular docking suggests that BAFP can strongly bind to HIgG. There are four hydrogen bond interac-tions between the drug and the residues Trp 170, Val 105, Met 139 and Asn 52. It was also considered that BAFP bound to HIgG mainly by a hydrophobic interaction, which is in good agreement with the results from the experi-mental thermodynamic parameters (the enthalpy change △Hθ and the entropy change △Sθ were calculated to be-6.70 kJ·mol-1 and 71.93 J·mol-1·K-1,respectively, according to the Van't Holf equation).

  17. Densities, Ultrasonic Speeds, Viscosities and Refractive Indices of Binary Mixtures of Benzene with Benzyl Alcohol,Benzonitrile, Benzoyl Chloride and Chlorobenzene at 303.15 K

    Institute of Scientific and Technical Information of China (English)

    ALI,A.; PANDEY,J.D.; SONI,N.K.; NAIN,A.K.; LAL,B.; CHAND,D.

    2005-01-01

    Densities, p, ultrasonic speeds, u, viscosities, η, and refractive indices, n, of pure benzene, benzyl alcohol (BA),benzonitrile (BN), benzoyl chloride (BC), chlorobenzene (CB) and their thirty six binary mixtures, with benzene as common component, were measured at 303.15 K over the entire mole fraction range. From these experimental data the values of deviations in ultrasonic speed, Au, isentropic compressibility, Δks, excess acoustic impedance, ZE, deviation in viscosity, Δη, and excess Gibbs free energy of activation of viscous flow, G*E, and partial molar isentropic compressibility, Kφ,2 of BA, BN, BC and CB in benzene were computed. The variation of these derived functions with composition of the mixtures suggested the increased cohesion (molecular order) in the solution and that interaction (A-B)>(A-A) or (B-B). Moreover, theoretical prediction of ultrasonic speed, viscosity and refractive index of all the four binary mixtures was made on the basis of empirical and semi-empirical relations by using the experimental values of the pure components. Comparison of theoretical results with the experimental values was made in order to assess the suitability of these relations in reproducing the experimental values of u, η and n. Also, molecular radii of pure liquids and the average molecular radii of binary mixtures were evaluated using the corresponding refractive indices of pure liquids and binary mixtures. The average molecular radii of binary mixtures were found to be additive with respect to mole fraction of the pure component.

  18. [Determination of hydrogen peroxide in rainwater by fluorometry].

    Science.gov (United States)

    Fang, Yan-Fen; Huang, Ying-Ping; Luo, Guang-Fu; Li, Rui-Ping

    2008-04-01

    The present paper introduces a new method using spectrofluorimetric analysis to determine the concentration of hydrogen peroxide in rainwater. In this method, an oxidation reaction is conducted between o-phenylenediamine (OPDA) and hydrogen peroxide in the buffer medium of NaAc-HAc at pH 4. 48 to form a new product 2,3-diaminophenazine (DAPN). Then the fluorescence intensity of DAPN is measured and 426 and 554 nm are chosen as the excitation and emission wavelengths. Therefore, with the foreknown concentration of input hydrogen peroxide, a series of fluorescence intensities of DAPN are acquired according to a series of different concentration of hydrogen peroxide as input, greatly improving the selectivity and sensibility of the system. A relationship between the input concentration of hydrogen peroxide and the fluorescence intensity of DAPN is then obtained using a linear regression. Results show that fluorescence intensity of DAPN is in proportion to the increase in the concentration of hydrogen peroxide in the range of 9.0 x 10(-7) -3.56 x 10(-5) mol x L(-1) almost linearly. The linear equation is F = 1.15c (micromol x L(-1))+398.6 (r = 0.999 1) and the detection limit is 2.7 x10(-7) mol x L(-1) (n = 11). The relative standard deviation of 11 parallel measurements with the concentration of H2O2 at 7.5 x 10(-6) and 3.0 x 10(-5) mol x L(-1), is 2.2 and 1.0%, respectively. Results from DPD method was used to verify this method. The interference of foreign iron was studied. Compared to the traditional methods, this binary system has a simplified operation and high sensitivity. The proposed method has been successfully applied to determine the concentration of hydrogen peroxide in rainwater.

  19. The Amoebicidal Effect of Ergosterol Peroxide Isolated from Pleurotus ostreatus.

    Science.gov (United States)

    Meza-Menchaca, Thuluz; Suárez-Medellín, Jorge; Del Ángel-Piña, Christian; Trigos, Ángel

    2015-12-01

    Dysentery is an inflammation of the intestine caused by the protozoan parasite Entamoeba histolytica and is a recurrent health problem affecting millions of people worldwide. Because of the magnitude of this disease, finding novel strategies for treatment that does not affect human cells is necessary. Ergosterol peroxide is a sterol particularly known as a major cytotoxic agent with a wide spectrum of biological activities produced by edible and medicinal mushrooms. The aim of this report is to evaluate the amoebicidal activity of ergosterol peroxide (5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol isolated from 5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol) (Jacq.) P. Kumm. f. sp. Florida. Our results show that ergosterol peroxide produced a strong cytotoxic effect against amoebic growth. The inhibitory concentration IC50 of ergosterol peroxide was evaluated. The interaction between E. histolytica and ergosterol peroxide in vitro resulted in strong amoebicidal activity (IC50  = 4.23 nM) that may be due to the oxidatory effect on the parasitic membrane. We also tested selective toxicity of ergosterol peroxide using a cell line CCL-241, a human epithelial cell line isolated from normal human fetal intestinal tissue. To the best of our knowledge, this is the first report on the cytotoxicity of ergosterol peroxide against E. histolytica, which uncovers a new biological property of the lipidic compound isolated from Pleurotus ostreatus (Jacq.) P. Kumm. f. sp. Florida.

  20. Hydrogen peroxide potentiates organophosphate toxicosis in chicks

    Directory of Open Access Journals (Sweden)

    Banan K. Al-Baggou

    2011-11-01

    Full Text Available Objective: The purpose of the present study was to examine the effect of hydrogen peroxide(H2O2 on the acute toxicity of organophosphate insecticides dichlorvos and diazinon and their inhibitoryactions on plasma, brain and liver cholinesterase activities. Material and Methods: H2O2 was given indrinking water (0.5% v/v for 2 weeks in unsexed day old chicks, a regimen known to induce oxidativestress in this species. A control group received drinking tap water. All experiments were conducted onthe chicks at the age of 15 days after exposure to H2O2. The acute (24 h oral LD50 values of dichlorvosand diazinon in the insecticidal preparations as determined by the up-and-down method in the controlchicks were 9.4 and 15.6 mg/kg, respectively. Results: The poisoned chicks manifested signs ofcholinergic toxicosis within one hour after the dosing including salivation, lacrimation, gasping, frequentdefecation, drooping of wings, tremors, convulsions and recumbency. The acute (24 h oral LD50 valuesof dichlorvos and diazinon in chicks provided with H2O2 were reduced to 3.5 and 6.5 mg/kg, by 63 and58%, respectively when compared to respective control LD50 values. The intoxicated chicks also showedcholinergic signs of toxicosis as described above. Plasma, brain and liver cholinesterase activities of thechicks exposed to H2O2 were significantly lower than their respective control (H2O values by 25, 28 and27%, respectively. Oral dosing of chicks with dichlorvos at 3 mg/kg significantly inhibited cholinesteraseactivities in the plasma, brain and liver of both control (42-67% and H2O2-treated (15-59% chicks.Diazinon at 5 mg/kg, orally also inhibited cholinesterase activities in the plasma, brain and liver of bothcontrol (36-66% and H2O2-treated (15-30% chicks. In the H2O2 groups, dichlorvos inhibition of livercholinesterase activity and diazinon inhibition of liver and brain cholinesterase activities weresignificantly lesser than those of the respective values of

  1. Effect of carbamide peroxide and hydrogen peroxide on enamel surface: an in vitro study.

    Science.gov (United States)

    Abouassi, Thaer; Wolkewitz, Martin; Hahn, Petra

    2011-10-01

    The aim of the study was to investigate changes in the micromorphologyl and microhardness of the enamel surface after bleaching with two different concentrations of hydrogen peroxide (HP) and carbamide peroxide (CP). Bovine enamel samples were embedded in resin blocks, and polished. Specimens in the experimental groups (n = 10) were treated with bleaching gels containing 10% CP, 35% CP, 3.6% HP, and 10% HP, respectively, for 2 h every second day over a period of 2 weeks. The gels had the identical composition and pH and differed only in their HP or CP content. The roughness and morphology of the enamel surface were analyzed using laser profilometry and SEM. Microhardness was measured using a Knoop hardness tester. The data were evaluated statistically. Specimens in the 10% HP group showed significantly higher roughness after bleaching compared to the control group (ΔRa, p = 0.01). Bleaching with 35% CP showed only a tendency to increase roughness (ΔRa, p = 0.06). Application of 10% CP or 3.6% HP had no significant influence on Ra. Enamel microhardness was significantly higher after application of 10% HP compared to the control (ΔMic = 8 KHN, p = 0.0002) and 35% CP (ΔMic = 20KHN, p = 0.01) groups. In summary, application of CP and HP showed only small quantitative and qualitative differences. In addition, the influence of bleaching procedure on the morphology and hardness of the enamel surface depended on the concentration of the active ingredients.

  2. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    Science.gov (United States)

    Zonios, George; Dimou, Aikaterini; Galaris, Dimitrios

    2008-01-01

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H2O2 solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  3. Micellar electrokinetic chromatography of organic and peroxide-based explosives.

    Science.gov (United States)

    Johns, Cameron; Hutchinson, Joseph P; Guijt, Rosanne M; Hilder, Emily F; Haddad, Paul R; Macka, Mirek; Nesterenko, Pavel N; Gaudry, Adam J; Dicinoski, Greg W; Breadmore, Michael C

    2015-05-30

    CE methods have been developed for the analysis of organic and peroxide-based explosives. These methods have been developed for deployment on portable, in-field instrumentation for rapid screening. Both classes of compounds are neutral and were separated using micellar electrokinetic chromatography (MEKC). The effects of sample composition, separation temperature, and background electrolyte composition were investigated. The optimised separation conditions (25 mM sodium tetraborate, 75 mM sodium dodecyl sulfate at 25°C, detection at 200 nm) were applied to the separation of 25 organic explosives in 17 min, with very high efficiency (typically greater than 300,000 plates m(-1)) and high sensitivity (LOD typically less than 0.5 mg L(-1); around 1-1.5 μM). A MEKC method was also developed for peroxide-based explosives (10 mM sodium tetraborate, 100 mM sodium dodecyl sulfate at 25°C, detection at 200 nm). UV detection provided LODs between 5.5 and 45.0 mg L(-1) (or 31.2-304 μM), which is comparable to results achieved using liquid chromatography. Importantly, no sample pre-treatment or post-column reaction was necessary and the peroxide-based explosives were not decomposed to hydrogen peroxide. Both MEKC methods have been applied to pre-blast analysis and for the detection of post-blast residues recovered from controlled, small scale detonations of organic and peroxide-based explosive devices.

  4. Multistage Extractive Reaction for Hydrogen Peroxide Production by Anthraquinone Process

    Institute of Scientific and Technical Information of China (English)

    WANG Li; L(U) Shuxiang; WANG Yaquan; MI Zhentao

    2005-01-01

    The extractive reaction process of oxygen-working solution-water three-phase system for the production of hydrogen peroxide by the anthraquinone method was investigated in a sieve plate column of 50 mm in internal diameter. The oxidation reaction of anthrahydroquinone in the working solution with oxygen and the extraction of hydrogen peroxide from the working solution into aqueous phase occurred simultaneously in the countercurrent mode. The agitating effect caused by gaseous phase made the droplets of the dispersed phase become smaller, thus, increasing the liquid-liquid interfacial contact areas and resulting in the improvement of the mass transfer velocity. Results showed that the gas-agitation had a beneficial effect on the extraction of hydrogen peroxide from the working solution into the aqueous phase; the concentration of hydrogen peroxide in the raffinate decreased with the increase of the gaseous superficial velocities; and the concentration of H2O2 in the raffinate increased with the increase of the dispersed phase superficial velocity at the same superficial velocity of the gaseous phase. In the G-L-L extractive reaction process, with the increase of the gaseous superficial velocities, both the conversion of the anthrahydroquinone oxidation and the extraction efficiency of hydrogen peroxide first increased significantly, then increased gradually.

  5. Safety issues of tooth whitening using peroxide-based materials.

    Science.gov (United States)

    Li, Y; Greenwall, L

    2013-07-01

    In-office tooth whitening using hydrogen peroxide (H₂O₂) has been practised in dentistry without significant safety concerns for more than a century. While few disputes exist regarding the efficacy of peroxide-based at-home whitening since its first introduction in 1989, its safety has been the cause of controversy and concern. This article reviews and discusses safety issues of tooth whitening using peroxide-based materials, including biological properties and toxicology of H₂O₂, use of chlorine dioxide, safety studies on tooth whitening, and clinical considerations of its use. Data accumulated during the last two decades demonstrate that, when used properly, peroxide-based tooth whitening is safe and effective. The most commonly seen side effects are tooth sensitivity and gingival irritation, which are usually mild to moderate and transient. So far there is no evidence of significant health risks associated with tooth whitening; however, potential adverse effects can occur with inappropriate application, abuse, or the use of inappropriate whitening products. With the knowledge on peroxide-based whitening materials and the recognition of potential adverse effects associated with the procedure, dental professionals are able to formulate an effective and safe tooth whitening regimen for individual patients to achieve maximal benefits while minimising potential risks.

  6. Lipid peroxidation and antioxidant enzymes in male infertility.

    Directory of Open Access Journals (Sweden)

    Dandekar S

    2002-07-01

    Full Text Available BACKGROUND AND AIM: Mammalian spermatozoa are rich in polyunsaturated fatty acids and are very susceptible to attack by reactive oxygen species (ROS and membrane lipid peroxide ion. Normally a balance is maintained between the amount of ROS produced and that scavenged. Cellular damage arises when this equilibrium is disturbed. A shift in the levels of ROS towards pro-oxidants in semen and vaginal secretions can induce an oxidative stress on spermatozoa. The aim was to study lipid peroxidation and antioxidant enzymes such as catalase, glutathione peroxidase and superoxide dismutase (SOD and to correlate the same, with the ′water test′, in male infertility. SETTINGS: Experimental study. SUBJECTS AND METHODS: Ejaculates from a total of 83 infertile and fertile healthy individuals were obtained. Lipid peroxidation and antioxidant enzyme levels were studied and correlated with water test. RESULTS: The results indicate that (i the antioxidant enzyme catalase showed no significant changes in the various pathological samples, (ii antioxidant enzymes SOD and glutathione peroxidase correlate positively with asthenozoospermic samples and (iii the degree of lipid peroxidation also correlates positively with the poorly swollen sperm tails. The increase in SOD and glutathione peroxidase values, in the pathological cases represents an attempt made to overcome the reactive oxygen species. CONCLUSION: Water test could be used as a preliminary marker test for sperm tail damage by reactive oxygen species, since it correlates very well with lipid peroxidation and antioxidant enzymes.

  7. Chlamydia trachomatis and sperm lipid peroxidation in infertile men

    Institute of Scientific and Technical Information of China (English)

    A.Segnini; M.I.Camejo; F.Proverbio

    2003-01-01

    Aim:To relate thepresence of anti-Chlamydial trachomatis IgA in semen with sperm lipid membrane peroxidation and changes in seminal parameters.Methods:Semen samples of the male partners of 52 couples assessed for undiagnosed infertility were examined for the presence of IgA antibody against C.trachomatis.The level of sperm membrane lipid peroxidation was estimated by determining the malondialdehyde(MDA) formation.Results:Sperm membrane of infertile males with positive IgA antibodies against C.trachomatis showed a higher level of lipid peroxidation than that of infertile males with negative IgA antibody(P<0.05).There was a positive correlation(P<0.01) between the level of C.trachomatis antibody and the magnitude of sperm membrane lipid peroxidation.All the other tested semen parameters were found to be similar in the two groups.Conclusion:The activation of immune system by C.trachomatis may promote lipid peroxidation of the sperm membrane.This could be the way by which C.trachomatis affects fertility.

  8. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zonios, George [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Dimou, Aikaterini [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Galaris, Dimitrios [Laboratory of Biological Chemistry, School of Medicine, University of Ioannina, 45110 Ioannina (Greece)

    2008-01-07

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H{sub 2}O{sub 2} solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  9. Catalytic wet hydrogen peroxide oxidation of a petrochemical wastewater.

    Science.gov (United States)

    Pariente, M I; Melero, J A; Martínez, F; Botas, J A; Gallego, A I

    2010-01-01

    Continuous Catalytic Wet Hydrogen Peroxide Oxidation (CWHPO) for the treatment of a petrochemical industry wastewater has been studied on a pilot plant scale process. The installation, based on a catalytic fixed bed reactor (FBR) coupled with a stirred tank reactor (STR), shows an interesting alternative for the intensification of a continuous CWHPO treatment. Agglomerated SBA-15 silica-supported iron oxide (Fe(2)O(3)/SBA-15) was used as Fenton-like catalyst. Several variables such as the temperature and hydrogen peroxide concentration, as well as the capacity of the pilot plant for the treatment of inlet polluted streams with different dilution degrees were studied. Remarkable results in terms of TOC reduction and increased biodegradability were achieved using 160 degrees C and moderate hydrogen peroxide initial concentration. Additionally, a good stability of the catalyst was evidenced for 8 hours of treatment with low iron leaching (less than 1 mg/L) under the best operating conditions.

  10. Synthesis of unstable cyclic peroxides for chemiluminescence studies

    Energy Technology Data Exchange (ETDEWEB)

    Bartoloni, Fernando H.; Oliveira, Marcelo A. de; Augusto, Felipe A.; Ciscato, Luiz Francisco M.L.; Bastos, Erick L.; Baader, Wilhelm J., E-mail: wjbaader@iq.usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Fundamental

    2012-11-15

    Cyclic four-membered ring peroxides are important high-energy intermediates in a variety of chemi and bioluminescence transformations. Specifically, a-peroxy lactones (1,2-dioxetanones) have been considered as model systems for efficient firefly bioluminescence. However, the preparation of such highly unstable compounds is extremely difficult and, therefore, only few research groups have been able to study the properties of these substances. In this study, the synthesis, purification and characterization of three 1,2-dioxetanones are reported and a detailed procedure for the known synthesis of diphenoyl peroxide, another important model compound for the chemical generation of electronically excited states, is provided. For most of these peroxides, the complete spectroscopic characterization is reported here for the first time. (author)

  11. Reproducing Phenomenology of Peroxidation Kinetics via Model Optimization

    Science.gov (United States)

    Ruslanov, Anatole D.; Bashylau, Anton V.

    2010-06-01

    We studied mathematical modeling of lipid peroxidation using a biochemical model system of iron (II)-ascorbate-dependent lipid peroxidation of rat hepatocyte mitochondrial fractions. We found that antioxidants extracted from plants demonstrate a high intensity of peroxidation inhibition. We simplified the system of differential equations that describes the kinetics of the mathematical model to a first order equation, which can be solved analytically. Moreover, we endeavor to algorithmically and heuristically recreate the processes and construct an environment that closely resembles the corresponding natural system. Our results demonstrate that it is possible to theoretically predict both the kinetics of oxidation and the intensity of inhibition without resorting to analytical and biochemical research, which is important for cost-effective discovery and development of medical agents with antioxidant action from the medicinal plants.

  12. Exposure to oxidized nitrogen: lipid peroxidation and neonatal health risk.

    Science.gov (United States)

    Tabacova, S; Baird, D D; Balabaeva, L

    1998-01-01

    Pregnant women exposed to extensive environmental contamination by oxidized nitrogen compounds were studied at parturition, their neonatal health status was assessed and the involvement of oxidative stress in pathology was evaluated. Methemoglobin in maternal and cord blood was measured as a biomarker of individual exposure. Blood lipid peroxides and glutathione (reduced and total) were determined as oxidative stress biomarkers. Birthweight, Apgar scores, and clinical diagnosis at birth were used as neonatal health endpoints. Elevated exposure to oxidized nitrogen compounds was associated with increased lipid peroxidation in both maternal and cord blood. Poor birth outcome was associated with high blood lipid peroxides. Controlling for maternal age, parity, and smoking did not affect the relationships materially. The results showed that maternal/fetal exposure to oxidized nitrogen compounds is associated with increased risk of adverse birth outcome and suggest a role of oxidative damage in the pathogenic pathway.

  13. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation

    DEFF Research Database (Denmark)

    Viswanathan, Venkatasubramanian; Hansen, Heine Anton; Nørskov, Jens K.

    2015-01-01

    device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen......Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized...... evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e(-) water oxidation to H2O2 and the 4e(-) oxidation to O2. We show that materials which bind oxygen intermediates...

  14. Study of catalase electrode for organic peroxides assays.

    Science.gov (United States)

    Horozova, Elena; Dimcheva, Nina; Jordanova, Zinaida

    2002-12-01

    The catalytic activity of immobilized catalase (EC 1.11.1.6) for two model peroxide compounds (dibenzoyl peroxide and 3-chloroperoxibenzoic acid) in a non-aqueous medium was used to prepare an organic-phase enzyme electrode (OPEE). The enzyme was immobilized within a polymeric film on spectrographic graphite. The amperometric signal of the enzyme electrode in substrate solutions was found to be due to the reduction of oxygen generated in the enzyme layer. The electrode response is proportional to peroxide concentrations up to about 40 microM within the potential range from -450 to -650 mV (vs. Ag/AgCl), and the response time is at most 90 s. The enzyme electrode retains about 35% of its initial activity after a 3-week storage at room temperature.

  15. Cathodic electrocatalyst layer for electrochemical generation of hydrogen peroxide

    Science.gov (United States)

    Rhodes, Christopher P. (Inventor); Tennakoon, Charles L. K. (Inventor); Singh, Waheguru Pal (Inventor); Anderson, Kelvin C. (Inventor)

    2011-01-01

    A cathodic gas diffusion electrode for the electrochemical production of aqueous hydrogen peroxide solutions. The cathodic gas diffusion electrode comprises an electrically conductive gas diffusion substrate and a cathodic electrocatalyst layer supported on the gas diffusion substrate. A novel cathodic electrocatalyst layer comprises a cathodic electrocatalyst, a substantially water-insoluble quaternary ammonium compound, a fluorocarbon polymer hydrophobic agent and binder, and a perfluoronated sulphonic acid polymer. An electrochemical cell using the novel cathodic electrocatalyst layer has been shown to produce an aqueous solution having between 8 and 14 weight percent hydrogen peroxide. Furthermore, such electrochemical cells have shown stable production of hydrogen peroxide solutions over 1000 hours of operation including numerous system shutdowns.

  16. Dinuclear manganese(II) complexes of hexaazamacrocycles bearing N-benzoylated pendant separated by aromatic spacers: Antibacterial, DNA interaction, cytotoxic and molecular docking studies.

    Science.gov (United States)

    Arthi, P; Shobana, S; Srinivasan, P; Prabhu, D; Arulvasu, C; Kalilur Rahiman, A

    2015-12-01

    Three new homodinuclear manganese(II) complexes of the type [Mn2L(1-3)(ClO4)(H2O)](ClO4)3 (1-3) have been synthesized via cyclocondensation of terephthalaldehyde with three different benzoylated pendants in the presence of manganese(II) perchlorate and characterized by spectroscopic methods. Cyclic voltammetric investigation of complexes (1-3) depict two quasi-reversible one electron reduction processes in the cathodic potential region (E(1)pc=-0.73 to-0.83 V, E(2)pc=-1.31 to -1.40 V) and two quasi-reversible one electron oxidation processes in the anodic potential region (E(1)pa=1.03 to 1.10 V, E(2)pa=1.69 to 1.77 V). Electronic absorption spectra of the complexes suggested tetrahedral geometry around the central metal ion. The observed low magnetic moment values (μeff, 5.60-5.68 B.M.) of the complexes indicate the presence of an antiferromagnetic spin-exchange interaction between two metal centers, which was also supported by the broad EPR signal. All the compounds were tested for antibacterial activity against Gram (-ve) and Gram (+ve) bacterial strains. The binding studies of complexes with CT-DNA suggested minor-groove mode of interaction. Molecular docking studies were carried out in order to find the binding affinity of complexes with DNA and protein EGFR Kinase. The complexes are stabilized by additional electrostatic and van der Waals interaction with the DNA, and support minor groove mode of binding. The cleavage activity of complexes on pBR322 plasmid DNA displays efficient activity through a mechanistic pathway involving hydroxyl radicals. The cytotoxicity of complexes 2 and 3 have been tested against human liver adenocarcinoma (HepG2) cell line. Nuclear-chromatin cleavage has also been observed with propidium iodide (PI) staining and alkaline single-cell gel electrophoresis (comet assay) techniques.

  17. Metal complexes of the nanosized ligand N-benzoyl-N‧-(p-amino phenyl) thiourea: Synthesis, characterization, antimicrobial activity and the metal uptake capacity of its ligating resin

    Science.gov (United States)

    Elhusseiny, Amel F.; Eldissouky, Ali; Al-Hamza, Ahmed M.; Hassan, Hammed H. A. M.

    2015-11-01

    The new nanosized N-benzoyl-N‧-(p-amino phenyl) thiourea ligand H2L was synthesized by nanoprecipitation method. The [Cu (H2L)2 Cl]·2H2O, [Zn (H2L)2(OAc)2], [Cd (H2L)2Cl2] and [Hg (H2L)2Cl2] complexes were synthesized and characterized by various physicochemical methods. Results revealed that the ligand act as hypodentate and bonded to the metal ion via the sulfur atom forming mononuclear non-electrolyte diamagnetic complex. Magnetic moment results indicated a reduction of Cu (II) to Cu (I) during the coordination process. Thermal studies demonstrated variable stabilities of the complexes and [Zn (H2L)2(OAc)2] exhibited the highest thermal stability while [Hg (H2L)2Cl2] was volatile. The prepared compounds were screened against different pathogenic microorganisms. The ligand performed high antibacterial activity against certain bacterial strain compared to its complexes, and the standard bacteriocide in use. The ligand was successfully immobilized on modified Amberlite XAD-16 forming the hypodentate ligating resin PS-SO2-H2L. The new resin was characterized and the extent of metal adsorption reached maximum at pH 6.0 for Cu (II), Cd (II) and Ag (I), with an adsorption amount of 4.3, 4.0 and 3.7 mmol g-1 respectively. The nanosized H2L represents a new category of promising adsorbent that would have a practical impact on biological and water treatment applications.

  18. Formation of a dinuclear copper(II) complex through the cleavage of CN bond of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole

    Science.gov (United States)

    Shardin, Rosidah; Pui, Law Kung; Yamin, Bohari M.; Kassim, Mohammad B.

    2014-09-01

    A simple mononuclear octahedral copper(II) complex was attempted from the reaction of three moles of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole and one mole of copper(II) perchlorate hexahydrate in methanol. However, the product of the reaction was confirmed to be a dinuclear copper(II) complex with μ-{3-(pyridin-2-yl)-pyrazolato} and 3-(pyridin-2-yl)-1H-pyrazole ligands attached to each of the Cu(II) centre atom. The copper(II) ion assisted the cleavage of the CbenzoylN bond afforded a 3-(pyridin-2-yl)-1H-pyrazole molecule. Deprotonation of the 3-(pyridin-2-yl)-1H-pyrazole gave a 3-(pyridin-2-yl)-pyrazolato, which subsequently reacted with the Cu(II) ion to give the {3-(pyridin-2-yl)-pyrazolato}{3-(pyridin-2-yl)-1H-pyrazole}Cu(II) product moiety. The structure of the dinuclear complex was confirmed by x-ray crystallography. The complex crystallized in a monoclinic crystal system with P2(1)/n space group and cell dimensions of a = 12.2029(8) Å, b = 11.4010(7) Å, c = 14.4052(9) Å and β = 102.414(2)°. The compound was further characterized by mass spectrometry, CHN elemental analysis, infrared and UV-visible spectroscopy and the results concurred with the x-ray structure. The presence of d-d transition at 671 nm (ɛ = 116 dm3 mol-1 cm-1) supports the presence of Cu(II) centres.

  19. Salinity-gradient energy driven microbial electrosynthesis of hydrogen peroxide

    DEFF Research Database (Denmark)

    Li, Xiaohu; Angelidaki, Irini; Zhang, Yifeng

    2017-01-01

    Hydrogen peroxide (H2O2) as a strong oxidant, is widely used in various chemical industries and environmental remediation processes. In this study, we developed an innovative method for cost-effective production of H2O2 by using a microbial reverse-electrodialysis electrolysis cell (MREC). In the......Hydrogen peroxide (H2O2) as a strong oxidant, is widely used in various chemical industries and environmental remediation processes. In this study, we developed an innovative method for cost-effective production of H2O2 by using a microbial reverse-electrodialysis electrolysis cell (MREC...

  20. Hydrogen peroxide modified sodium titanates with improved sorption capabilities

    Science.gov (United States)

    Nyman, May D.; Hobbs, David T.

    2009-02-24

    The sorption capabilities (e.g., kinetics, selectivity, capacity) of the baseline monosodium titanate (MST) sorbent material currently being used to sequester Sr-90 and alpha-emitting radioisotopes at the Savannah River Site are significantly improved when treated with hydrogen peroxide; either during the original synthesis of MST, or, as a post-treatment step after the MST has been synthesized. It is expected that these peroxide-modified MST sorbent materials will have significantly improved sorption capabilities for non-radioactive cations found in industrial processes and waste streams.

  1. Mass Spectrometry of 2a,4-Disubstituted 5-Benzoyl-2a,3,4,5-tetrahydro-2-phenoxy-azeto[1,2-a][1,5]benzodiazepin-1(2H)-ones Under Electron Impact Ionization Conditions

    Institute of Scientific and Technical Information of China (English)

    XU Jia-xi; HUANG Xu

    2005-01-01

    The mass spectrometric fragmentation of 2a,4-disubstituted 5-benzoyl-2a,3,4,5-tetrahydro-2-phenoxy-azeto[1,2-a][1,5]benzodiazepin-1(2H)-ones has been investigated by means of mass-analyzed ion kinetic energy spectrometry under electron impact ionization conditions. All compounds tend to lose different moieties, such as phenoxy, phenoxy and H, and phenoxyketene. Both [M+-PhO] and [M+-PhOH] ions could further lose CO, and the [M+-PhOCH=C=O] ions could lose propene or styrene, PhCON, PhCOHN, and other fragments.

  2. Applications of hydrogen peroxide in electrochemical technology

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Gallegos, Alberto Armando

    1998-12-01

    It is demonstrated that hydrogen peroxide can be produced with a current efficiency of 40-70% by the cathodic reduction of oxygen at a reticulated vitreous carbon electrode in a divided flow-cell using catholytes consisting of aqueous chloride or sulphate media, pH >>{sub 2}. The supporting electrolyte does not influence either the current efficiency for H{sub 2}O{sub 2} or its rate of production. The current efficiency for H{sub 2}O{sub 2} is not a strong function of the potential and this suggests that 2e- and 4e- reduction of oxygen occurs in parallel at different sites on the carbon surface. Voltammetry experiments showed that (a) the I-E response for oxygen reduction at pH >>{sub 2} is a function of the electrode surface and/or the supporting electrolyte; (b) both H{sub 2} evolution and oxygen reduction are retarded on carbon with increasing ionic strength; (c) the presence of ferrous ions lead to the homogeneous decomposition of H{sub 2}O{sub 2} away from the cathode surface but their effectiveness as a catalyst for this decomposition depends on their speciation in solution which changes during an electrolysis. The use of a three-dimensional electrode fabricated from reticulated vitreous carbon allows Fenton`s reagent to be electroproduced at a practical rate which makes possible the removal of organics in slightly acidic aqueous media. A wide range of highly toxic organic molecules (phenol, catechol, hydroquinone, p-benzoquinone, oxalic acid, aniline, cresol and amaranth) have been oxidised in mild conditions and a significant fraction of the organic carbon is evolved as CO{sub 2}. In all cases studied the initial chemical oxygen demand (COD) was depleted to levels higher than 85%, indicating a complete mineralisation of the organic pollutants. The life-time of the reticulated vitreous carbon cathode was demonstrated to be over 1000 hours during two and a half years of experiments. During this time the cathode performance was very good, leading to

  3. Effect of americium-241 on luminous bacteria. Role of peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrova, M., E-mail: maka-alexandrova@rambler.r [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Rozhko, T. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Vydryakova, G. [Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation); Kudryasheva, N. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation)

    2011-04-15

    The effect of americium-241 ({sup 241}Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of {sup 241}Am in nutrient media (0.16-6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 {sup o}C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the {sup 241}Am is discussed. The effect of {sup 241}Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in {sup 241}Am solutions was demonstrated; and the similarity of {sup 241}Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions. - Highlights: {yields} Am-241 in water solutions (A = 0.16-6.7 kBq/L) suppresses bacterial growth.{yields} Am-241 (A = 0.16-6.7 kBq/L) stimulate bacterial luminescence. {yields} Peroxides, secondary radiolysis products, cause increase of bacterial luminescence.

  4. Hydrogen peroxide in breath condensate during a common cold

    NARCIS (Netherlands)

    R.Q. Jöbsis (Rijn); S.L. Schellekens; A. Fakkel-Kroesbergen (Anoeska); R.H. Raatgeep (Rolien); J.C. de Jongste (Johan)

    2001-01-01

    textabstractBackground: Hydrogen peroxide (H2O2) in exhaled air condensate is elevated in inflammatory disorders of the lower respiratory tract. It is unknown whether viral colds contribute to exhaled H2O2. Aim: To assess exhaled H2O2during and after a common cold. Methods: We examined H2O2in the br

  5. Selective electrochemical generation of hydrogen peroxide from water oxidation

    CERN Document Server

    Viswanathan, Venkatasubramanian; Nørskov, Jens K

    2015-01-01

    Water is a life-giving source, fundamental to human existence, yet, over a billion people lack access to clean drinking water. Present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH$^*$ can be used as a descriptor to screen for selectivity trends between the 2e$^-$ water oxidation to H$_2$O$_2$ and the 4e$^-$ oxidation to O$_2$. We show that materials that bind oxygen intermediates sufficiently weakly, such as SnO$_2$, can activate hydrogen peroxide evolution. We present a rati...

  6. Sol - Gel synthesis and characterization of magnesium peroxide nanoparticles

    Science.gov (United States)

    Jaison, J.; Ashok raja, C.; Balakumar, S.; Chan, Y. S.

    2015-04-01

    Magnesium peroxide is an excellent source of oxygen in agriculture applications, for instance it is used in waste management as a material for soil bioremediation to remove contaminants from polluted underground water, biological wastes treatment to break down hydrocarbon, etc. In the present study, sol-gel synthesis of magnesium peroxide (MgO2) nanoparticles is reported. Magnesium peroxide is odourless; fine peroxide which releases oxygen when reacts with water. During the sol-gel synthesis, the magnesium malonate intermediate is formed which was then calcinated to obtain MgO2 nanoparticles. The synthesized nanoparticles were characterized using Thermo gravimetric -Differential Thermal Analysis (TG- DTA), X-Ray Diffraction studies (XRD) and High Resolution Transmission Electron Microscope (HRTEM). Our study provides a clear insight that the formation of magnesium malonate during the synthesis was due to the reaction between magnesium acetate, oxalic acid and ethanol. In our study, we can conclude that the calcination temperature has a strong influence on particle size, morphology, monodispersity and the chemistry of the particles.

  7. Hydrogen peroxide evolution during V-UV photolysis of water.

    Science.gov (United States)

    Azrague, Kamal; Bonnefille, Eric; Pradines, Vincent; Pimienta, Véronique; Oliveros, Esther; Maurette, Marie-Thérèse; Benoit-Marquié, Florence

    2005-05-01

    Hydrogen peroxide evolution during the vacuum-ultraviolet (V-UV, 172 nm) photolysis of water is considerably affected by the presence of oxalic acid (employed as a model water pollutant) and striking differences are observed in the absence and in the presence of dioxygen.

  8. The design of organic catalysis for epoxidation by hydrogen peroxide

    OpenAIRE

    Alder, Roger W.; Davis, Anthony P

    2005-01-01

    The potential of various organic species to catalyze epoxidation of ethene by hydrogen peroxide is explored with B3LYP/6-31G* DFT calculations. Electronic Supplementary Materials Supplementary material is available for this article at http://dx.doi.org/10.1007/s00894-005-0044-4.

  9. Peroxide Propulsion at the Turn of the Century

    Science.gov (United States)

    Anderson, William E.; Butler, Kathy; Crocket, Dave; Lewis, Tim; McNeal, Curtis

    2000-01-01

    A resurgence of interest in peroxide propulsion has occurred in the last years of the 21st Century. This interest is driven by the need for lower cost propulsion systems and the need for storable reusable propulsion systems to meet future space transportation system architectures. NASA and the Air Force are jointly developing two propulsion systems for flight demonstration early in the 21st Century. One system will be a development of Boeing's AR2-3 engine, which was successfully fielded in the 1960s. The other is a new pressure-fed design by Orbital Sciences Corporation for expendable mission requirements. Concurrently NASA and industry are pursuing the key peroxide technologies needed to design, fabricate, and test advanced peroxide engines to meet the mission needs beyond 2005. This paper will present a description of the AR2-3, report the status of its current test program, and describe its intended flight demonstration. This paper will then describe the Orbital 10K engine, the status of its test program, and describe its planned flight demonstration. Finally the paper will present a plan, or technology roadmap, for the development of an advanced peroxide engine for the 21st Century.

  10. Computer Data Processing of the Hydrogen Peroxide Decomposition Reaction

    Institute of Scientific and Technical Information of China (English)

    余逸男; 胡良剑

    2003-01-01

    Two methods of computer data processing, linear fitting and nonlinear fitting, are applied to compute the rate constant for hydrogen peroxide decomposition reaction. The results indicate that not only the new methods work with no necessity to measure the final oxygen volume, but also the fitting errors decrease evidently.

  11. Enzymatic generation of hydrogen peroxide shows promising antifouling effect

    DEFF Research Database (Denmark)

    Kristensen, J.B.; Olsen, Stefan Møller; Laursen, B.S.;

    2010-01-01

    The antifouling (AF) potential of hydrogen peroxide (H2O2) produced enzymatically in a coating containing starch, glucoamylase, and hexose oxidase was evaluated in a series of laboratory tests and in-sea field trials. Dissolved H2O2 inhibited bacterial biofilm formation by eight of nine marine...

  12. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation.

    Science.gov (United States)

    Viswanathan, Venkatasubramanian; Hansen, Heine A; Nørskov, Jens K

    2015-11-01

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e(-) water oxidation to H2O2 and the 4e(-) oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. We present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.

  13. The basic chemistry and photochemistry behind hydrogen peroxide tooth whitening

    NARCIS (Netherlands)

    Young, N.D.; Fairley, P.D.; Mohan, V.; Jumeaux, C.

    2013-01-01

    Tooth whitening using hydrogen peroxide gel formulation is a complexprocess which involves both chemistry and physics, and there is still some controversy about the efficiency of whitening processes, particularly with respect to the roles of temperature and irradiation with light. In this work we av

  14. Hydrogen peroxide oxidant fuel cell systems for ultra-portable applications

    Science.gov (United States)

    Valdez, T. I.; Narayanan, S. R.

    2001-01-01

    This paper will address the issues of using hydrogen peroxide as an oxidant fuel in a miniature DMFC system. Cell performance for DMFC based fuel cells operating on hydrogen peroxide will be presented and discussed.

  15. 78 FR 73697 - New Animal Drugs; Hyaluronate Sodium; Hydrogen Peroxide; Imidacloprid and Moxidectin; Change of...

    Science.gov (United States)

    2013-12-09

    ...; Hyaluronate Sodium; Hydrogen Peroxide; Imidacloprid and Moxidectin; Change of Sponsor AGENCY: Food and Drug... interest in, NADA 141-255 for PEROX-AID (hydrogen peroxide) 35% Solution to Western Chemical, Inc.,...

  16. Blood antioxidant status and erythrocyte lipid peroxidation following distance running.

    Science.gov (United States)

    Duthie, G G; Robertson, J D; Maughan, R J; Morrice, P C

    1990-10-01

    The relationship between prolonged exercise, oxidative stress, and the protective capacity of the antioxidant defense system has been determined. Venous blood samples were removed from seven trained athletes before and up to 120 h after completion of a half-marathon for measurements of blood antioxidants, antioxidant enzymes, and indices of lipid peroxidation. Plasma creatine kinase (CK) activity, an index of muscle damage, increased (P less than 0.05) to a maximum 24 h after the race but this was not accompanied by changes in conjugated dienes and thiobarbituric acid reactive substances (TBARS), which are indices of lipid peroxidation. An increase (P less than 0.05) in plasma cholesterol concentration (4%) immediately after the race was similar to the change in plasma volume (6%). However, transient increases (P less than 0.05) immediately postrace in the plasma concentrations of uric acid (24%), vitamin A (18%), and vitamin C (34%) were only partly accounted for by the fluid shifts. The immediate postrace increases in alpha- and gamma-tocopherol did not attain statistical significance. Erythrocyte antioxidant enzyme activities were unaffected by the exercise but the alpha- and gamma-tocopherol concentrations progressively increased (P less than 0.001 and P less than 0.05, respectively) up to 48 h postrace. Paradoxically, 24 h after the race erythrocyte susceptibility to in vitro peroxidation was markedly elevated (P less than 0.01). This enhanced susceptibility to peroxidation was maintained even at 120 h postrace and did not correspond to changes in the age of the red cell population. A decrease (P less than 0.001) in total erythrocyte glutathione immediately after the half-marathon was mainly due to a reduction in the reduced form (GSH). The results show that when trained athletes run a comparatively short distance sufficient to result in some degree of muscle damage but which is insufficient to cause elevations in plasma indices of lipid peroxidation

  17. How hydrogen peroxide is metabolized by oxidized cytochrome c oxidase.

    Science.gov (United States)

    Jancura, Daniel; Stanicova, Jana; Palmer, Graham; Fabian, Marian

    2014-06-10

    In the absence of external electron donors, oxidized bovine cytochrome c oxidase (CcO) exhibits the ability to decompose excess H2O2. Depending on the concentration of peroxide, two mechanisms of degradation were identified. At submillimolar peroxide concentrations, decomposition proceeds with virtually no production of superoxide and oxygen. In contrast, in the millimolar H2O2 concentration range, CcO generates superoxide from peroxide. At submillimolar concentrations, the decomposition of H2O2 occurs at least at two sites. One is the catalytic heme a3-CuB center where H2O2 is reduced to water. During the interaction of the enzyme with H2O2, this center cycles back to oxidized CcO via the intermediate presence of two oxoferryl states. We show that at pH 8.0 two molecules of H2O2 react with the catalytic center accomplishing one cycle. In addition, the reactions at the heme a3-CuB center generate the surface-exposed lipid-based radical(s) that participates in the decomposition of peroxide. It is also found that the irreversible decline of the catalytic activity of the enzyme treated with submillimolar H2O2 concentrations results specifically from the decrease in the rate of electron transfer from heme a to the heme a3-CuB center during the reductive phase of the catalytic cycle. The rates of electron transfer from ferrocytochrome c to heme a and the kinetics of the oxidation of the fully reduced CcO with O2 were not affected in the peroxide-modified CcO.

  18. LIPID PEROXIDATION AND JOB STRESS IN DENTAL HEALTHCARE WORKERS

    Directory of Open Access Journals (Sweden)

    S. V. Melnikova

    2014-04-01

    Full Text Available This study devoted to the lipid peroxidation indices in dentists target group as a marker of psycho-emotional state. We revealed increase in the level of TBA-active products in female and male dentists during job stress. There was strong decrease in level of TBA-active products in control group of dentist that study during the lectures. Activation of lipid peroxidation in dentists during dentist examination can be considered as non-specific component of reactions towards the stressors of professional activities. We also revealed that the initial level of TBA-active products in female and male dentists before the outpatient dental reception was higher than that of dentists that study before lectures. This is indicates the mobilization of sympathetic nervous system before beginning of the working day. The contents of the level of TBA-active products in the oral fluid of female and male dentists after dental examination significantly increased, whereas these indices decreased in the group of dentists that study after the lectures. The increasing of TBA-active products in dentists after outpatient dental reception was by 42.5 % and 77 % higher compared with a group of dentists that study in the lecture classes. The results of correlation analysis suggest the influence of lipid peroxidation processes on the cardiovascular and blood system of dentists during job stress. Activation of lipid peroxidation in dentists during dental examination can be considered as non-specific component of the body's response to stressors influence in professional activities. Key words: dentists, activation of lipid peroxidation, psychoemotional stress, job stress.

  19. ALKALI DARKENING AND ITS RELATIONSHIP TO PEROXIDE BLEACHING OF MECHANICAL PULP

    Institute of Scientific and Technical Information of China (English)

    Zhibin He; Yonghao Ni; Eric Zhang

    2004-01-01

    The effect of alkalinity, transition metals and oxygen on alkali darkening of mechanical pulp, and its relations to subsequent peroxide bleaching were investigated. The chromophores generated under mild conditions of an alkaline treatment can be destroyed in a subsequent peroxide stage.Peroxide-resistant chromophores are generated only under severe conditions. The results also show that a short alkaline pretreatment can improve the performance of a peroxide bleaching stage.

  20. ALKALI DARKENING AND ITS RELATIONSHIP TO PEROXIDE BLEACHING OF MECHANICAL PULP

    Institute of Scientific and Technical Information of China (English)

    ZhibinHe; Yon2haoNi; EricZhang_

    2004-01-01

    The effect of alkalinity, transition metals and oxygen on alkali darkening of mechanical pulp, and its relations to subsequent peroxide bleaching were investigated. The chromophores generated under mild conditions of an alkaline treatment can be destroyed in a subsequent peroxide stage. Peroxide-resistant chromophores are generated only under severe conditions. The results also show that a short alkaline pretreatment can improve the performance of a peroxide bleaching stage.

  1. [Dynamics of lipid peroxidation and steroidogenesis in adrenal cortex during stress].

    Science.gov (United States)

    Doroshkevich, N A; Antsulevich, S N; Vinogradov, V V

    1990-01-01

    The phase character of lipid peroxidation has been found in the rabbit adrenal cortex in the process of adaptation to extreme loads. Under acute stress the activation of lipid peroxidation is directly dependent on the hormonal synthesis processes. Under conditions of the prolonged stress factor an enhancement of the lipid peroxidation intensity in the adrenal cortex coincides with a decrease in the steroidogenesis rate.

  2. Catalytic hydrogen peroxide decomposition on La1-xSrxCo03-d perovskite oxides

    NARCIS (Netherlands)

    Dam, Van-Ahn. T.; Olthuis, W.; Bergveld, P.; Berg, van den A.

    2005-01-01

    Lanthanide perovskite oxides are mentioned as material for hydrogen peroxide sensor because they can catalytically decompose hydrogen peroxide in an aqueous medium. The catalytic properties of these perovskite oxides to hydrogen peroxide are suggested due to their oxygen vacancies influenced by the

  3. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Silver nitrate and hydrogen peroxide solution. 172... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution containing a mixture of silver nitrate and hydrogen peroxide may be safely...

  4. Oxidative status imbalance in patients with metabolic syndrome: role of the myeloperoxidase/hydrogen peroxide axis.

    Science.gov (United States)

    da Fonseca, Lucas José Sá; Nunes-Souza, Valéria; Guedes, Glaucevane da Silva; Schettino-Silva, Glauber; Mota-Gomes, Marco Antônio; Rabelo, Luíza Antas

    2014-01-01

    The present study evaluated the cardiometabolic and redox balance profiles in patients with Metabolic Syndrome compared to apparently healthy individuals, and the participation of the myeloperoxidase/hydrogen peroxide axis in systemic lipid peroxidation. Twenty-four patients with Metabolic Syndrome and eighteen controls underwent a full clinical assessment. Venous blood samples were collected for general biochemical dosages, as well as for the oxidative stress analyses (superoxide dismutase, catalase, and arginase activities; and lipid peroxidation, myeloperoxidase activity, nitrite, and hydrogen peroxide concentrations in plasma). Arterial stiffness was assessed by radial artery applanation tonometry. Plasma lipid peroxidation, erythrocyte superoxide dismutase activity, myeloperoxidase activity, and hydrogen peroxide concentrations were shown to be increased in Metabolic Syndrome patients, without significant differences for the other enzymes, plasma nitrite concentrations, and arterial stiffness. Linear regression analysis revealed a positive and significant correlation between lipid peroxidation and myeloperoxidase and also between this enzyme and hydrogen peroxide. In contrast, such correlation was not observed between lipid peroxidation and hydrogen peroxide. In summary, Metabolic Syndrome patients exhibited evident systemic redox imbalance compared to controls, with the possible participation of the myeloperoxidase/hydrogen peroxide axis as a contributor in lipid peroxidation.

  5. Protective mechanisms against peptide and protein peroxides generated by singlet oxygen

    DEFF Research Database (Denmark)

    Morgan, Philip E; Dean, Roger T; Davies, Michael Jonathan

    2004-01-01

    or detoxify such peroxides. It is shown that catalase, horseradish peroxidase, and Cu/Zn superoxide dismutase do not react rapidly with these peroxides. Oxymyoglobin and oxyhemoglobin, but not the met (Fe3+) forms of these proteins, react with peptide but not protein, peroxides with oxidation of the heme iron...

  6. Less sensitive oxygen-rich organic peroxides containing geminal hydroperoxy groups.

    Science.gov (United States)

    Gamage, Nipuni-Dhanesha H; Stiasny, Benedikt; Stierstorfer, Jörg; Martin, Philip D; Klapötke, Thomas M; Winter, Charles H

    2015-09-04

    A series of oxygen-rich organic peroxide compounds each containing two bis(hydroperoxy)methylene groups is described. Energetic testing shows that these compounds are much less sensitive toward impact and friction than existing classes of organic peroxides. The compounds are highly energetic, which may lead to practical peroxide-based explosives.

  7. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hydrogen Peroxide Production Subcategory § 415.90 Applicability; description of the hydrogen peroxide production subcategory. The provisions of this subpart are applicable to...

  8. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Hydrogen peroxide; exemption from the... Exemptions From Tolerances § 180.1197 Hydrogen peroxide; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of hydrogen peroxide in or on...

  9. Synthesis, spectroscopic and theoretical studies of ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate butanol solvate

    Science.gov (United States)

    Koca, İrfan; Sert, Yusuf; Gümüş, Mehmet; Kani, İbrahim; Çırak, Çağrı

    2014-01-01

    We have synthesized ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate (2) by the reaction of 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carbonyl chloride (1), ammonium thiocyanate and ethyl 3-aminobut-2-enoate and then characterized by elemental analyses, IR, Raman, 1H NMR, 13C NMR and X-ray diffraction methods. The experimental and theoretical vibrational spectra of 2 were investigated. The experimental FT-IR (4000-400 cm-1) and Laser-Raman spectra (4000-100 cm-1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles) were calculated using Ab Initio Hartree Fock (HF), Density Functional Theory (B3LYP) methods with 6-311++G(d,p) basis set by Gaussian 09W program. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies were calculated.

  10. Organic peroxides' gas-particle partitioning and rapid heterogeneous decomposition on secondary organic aerosol

    Science.gov (United States)

    Li, Huan; Chen, Zhongming; Huang, Liubin; Huang, Dao

    2016-02-01

    Organic peroxides, important species in the atmosphere, promote secondary organic aerosol (SOA) aging, affect HOx radicals cycling, and cause adverse health effects. However, the formation, gas-particle partitioning, and evolution of organic peroxides are complicated and still unclear. In this study, we investigated in the laboratory the production and gas-particle partitioning of peroxides from the ozonolysis of α-pinene, which is one of the major biogenic volatile organic compounds in the atmosphere and an important precursor for SOA at a global scale. We have determined the molar yields of hydrogen peroxide (H2O2), hydromethyl hydroperoxide (HMHP), peroxyformic acid (PFA), peroxyacetic acid (PAA), and total peroxides (TPOs, including unknown peroxides) and the fraction of peroxides in α-pinene/O3 SOA. Comparing the gas-phase peroxides with the particle-phase peroxides, we find that gas-particle partitioning coefficients of PFA and PAA are 104 times higher than the values from the theoretical prediction, indicating that organic peroxides play a more important role in SOA formation than previously expected. Here, the partitioning coefficients of TPO were determined to be as high as (2-3) × 10-4 m3 µg-1. Even so, more than 80 % of the peroxides formed in the reaction remain in the gas phase. Water changes the distribution of gaseous peroxides, while it does not affect the total amount of peroxides in either the gas or the particle phase. Approx. 18 % of gaseous peroxides undergo rapid heterogeneous decomposition on SOA particles in the presence of water vapor, resulting in the additional production of H2O2. This process can partially explain the unexpectedly high H2O2 yields under wet conditions. Transformation of organic peroxides to H2O2 also preserves OH in the atmosphere, helping to improve the understanding of OH cycling.

  11. Chemiluminometric hydrogen peroxide sensor for flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Preuschoff, F. (Inst. fuer Biotechnologie, Halle Univ. (Germany)); Spohn, U. (Inst. fuer Biotechnologie, Halle Univ. (Germany)); Blankenstein, G. (Inst. fuer Enzymtechnologie am Forschungszentrum Juelich GmbH, Duesseldorf Univ., Juelich (Germany)); Mohr, K.H. (Inst. fuer Biotechnologie, Halle Univ. (Germany)); Kula, M.R. (Inst. fuer Enzymtechnologie am Forschungszentrum Juelich GmbH, Duesseldorf Univ., Juelich (Germany))

    1993-08-01

    A chemiluminometric hydrogen peroxide sensor was developed for fast flow injection analysis. Different peroxidases were covalently immobilized on affinity membranes and compared with respect to the catalytic luminol oxidation. A photomultiplier tube is connected with a fibre bundle to the flow cell. The small cell volume of 5-10 [mu]l allows sampling rates between 90 and 200/h, depending on the flow rate. The highest sensitivity and the best longterm stability can be achieved with microbial peroxidase. Hydrogen peroxide can be determined in the range between 10[sup -3] and 10[sup -8] mol/l with a precision of < 3% (n=6, [alpha] = 0.05). The operational stability of the sensor is longer than 10 weeks. (orig.)

  12. EVALUATION OF ANTIOXIDANTS AND LIPID PEROXIDATION STATUS AMONG STUDENTS

    Directory of Open Access Journals (Sweden)

    Anandh T

    2012-12-01

    Full Text Available The study aims to estimate the changes in the plasma levels of lipid peroxidation product malondialdehyde (MDA, non-enzymatic antioxidants: vitamin C and E and enzymatic antioxidant: superoxide dismutase (SOD. The population used were healthy students (100 male, 100 female; mean age 22.4 years, range 18- 25 years. The level of lipid peroxidation was found to be significantly increased among the students which were inversely related to the level of antioxidants (p<0.05. Increased antioxidant levels show a multiple link between fruit and vegetable intake among the study group. Diminished antioxidant status disturbed oxidant-antioxidant balance alleviating oxidative stress state in less fruit and vegetable intake group. Therefore, the alterations in the level of antioxidants in blood plasma could be used as biomarkers for nutritional tribulations.

  13. Hydrogen Peroxide: A Key Chemical for Today's Sustainable Development.

    Science.gov (United States)

    Ciriminna, Rosaria; Albanese, Lorenzo; Meneguzzo, Francesco; Pagliaro, Mario

    2016-12-20

    The global utilization of hydrogen peroxide, a green oxidant that decomposes in water and oxygen, has gone from 0.5 million tonnes per year three decades ago to 4.5 million tonnes per year in 2014, and is still climbing. With the aim of expanding the utilization of this eminent green chemical across different industrial and civil sectors, the production and use of hydrogen peroxide as a green industrial oxidant is reviewed herein to provide an overview of the explosive growth of its industrial use over the last three decades and of the state of the art in its industrial manufacture, with important details of what determines the viability of the direct production from oxygen and hydrogen compared with the traditional auto-oxidation process.

  14. Preparation of water soluble chitosan by hydrolysis using hydrogen peroxide.

    Science.gov (United States)

    Xia, Zhenqiang; Wu, Shengjun; Chen, Jinhua

    2013-08-01

    Chitosan is not soluble in water, which limits its wide application particularly in the medicine and food industry. In the present study, water soluble chitosan (WSC) was prepared by hydrolyzing chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid in homogeneous phase. Factors affecting hydrolysis were investigated and the optimal hydrolysis conditions were determined. The WSC structure was characterized by Fourier transform infrared spectroscopy. The resulting products were composed of chitooligosaccharides of DP 2-9. The WSC content of the product and the yield were 94.7% and 92.3% (w/w), respectively. The results indicate that WSC can be effectively prepared by hydrolysis of chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid.

  15. Peroxiredoxins: guardians against oxidative stress and modulators of peroxide signaling.

    Science.gov (United States)

    Perkins, Arden; Nelson, Kimberly J; Parsonage, Derek; Poole, Leslie B; Karplus, P Andrew

    2015-08-01

    Peroxiredoxins (Prxs) are a ubiquitous family of cysteine-dependent peroxidase enzymes that play dominant roles in regulating peroxide levels within cells. These enzymes, often present at high levels and capable of rapidly clearing peroxides, display a remarkable array of variations in their oligomeric states and susceptibility to regulation by hyperoxidative inactivation and other post-translational modifications. Key conserved residues within the active site promote catalysis by stabilizing the transition state required for transferring the terminal oxygen of hydroperoxides to the active site (peroxidatic) cysteine residue. Extensive investigations continue to expand our understanding of the scope of their importance as well as the structures and forces at play within these critical defense and regulatory enzymes.

  16. Lycopene control of benzophenone-sensitized lipid peroxidation

    Science.gov (United States)

    Cvetković, Dragan; Marković, Dejan

    2012-05-01

    Lycopene antioxidant activity in the presence of two different mixtures of phospholipids in hexane solution, under continuous regime of UV-irradiation from three different ranges (UV-A, UV-B, and UV-C) has been evaluated in this work. Lycopene expected role was to control lipid peroxidation, by scavenging free radicals generated by UV-irradiation, in the presence and in the absence of selected photosensitizer, benzophenone. This work shows that lycopene undergoes to UV-induced destruction (bleaching), highly dependent on the incident photons energy input, more expressed in the presence than in the absence of benzophenone. The further increase ("excess") of its bleaching is undoubtedly related to the further increase of its antioxidant activity in the presence of benzophenone, having the same cause: increase of (phospholipids peroxidation) chain-breaking activities.

  17. Iron Supplements and Magnesium Peroxide: An Example of a Hazardous Combination in Self-Medication.

    Science.gov (United States)

    Vrolijk, Misha F; Opperhuizen, Antoon; Jansen, Eugène H J M; Bast, Aalt; Haenen, Guido R M M

    2016-10-01

    The use of self-medication, which includes dietary supplements and over-the-counter drugs, is still on the rise, while safety issues are not well addressed yet. This especially holds for combinations. For example, iron supplements and magnesium peroxide both produce adverse effects via the formation of reactive oxygen species (ROS). This prompted us to investigate the effect of the combination of three different iron supplements with magnesium peroxide on ROS formation. Hydroxyl radical formation by the three iron supplements either combined with magnesium peroxide or alone was determined by performing a deoxyribose assay. Free iron content of iron supplements was determined using ferrozine assay. To determine hydrogen peroxide formation by magnesium peroxide, a ferrous thiocyanate assay was performed. Finally, electron spin resonance spectroscopy (ESR) was performed to confirm the formation of hydroxyl radicals. Our results show that magnesium peroxide induces the formation of hydrogen peroxide. All three iron supplements induced the formation of the extremely reactive hydroxyl radical, although the amount of radicals formed by the different supplements differed. It was shown that combining iron supplements with magnesium peroxide increases radical formation. The formation of hydroxyl radicals after the combination was confirmed with ESR. All three iron supplements contained labile iron and induced the formation of hydroxyl radicals. Additionally, magnesium peroxide in water yields hydrogen peroxide, which is converted into hydroxyl radicals by iron. Hence, iron supplements and magnesium peroxide is a hazardous combination and exemplifies that more attention should be given to combinations of products used in self-medication.

  18. Ultrasonic degradation of Rhodamine B in the presence of hydrogen peroxide and some metal oxide.

    Science.gov (United States)

    Mehrdad, Abbas; Hashemzadeh, Robab

    2010-01-01

    In this research, degradation of Rodamine B in the presence of (hydrogen peroxide), (hydrogen peroxide+ultrasound), (hydrogen peroxide+aluminum oxide), (hydrogen peroxide+aluminum oxide+ultrasound with different ultrasound power), (hydrogen peroxide+iron oxide) and (hydrogen peroxide+iron oxide+ultrasound with different ultrasound power) were investigated at 25 degrees C. The apparent rate constants for the examined systems were calculated by pseudo-first-order kinetics. The results indicate that the rate of degradation was accelerated by ultrasound. The rate of degradation was increased by increasing power ultrasound. The efficiency of the (hydrogen peroxide+iron oxide+ultrasound) system for degradation of Rodamine B was higher than the others examined.

  19. The kinetic study of oxidation of iodine by hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Cantrel, L. [Institut de Protection et de Surete Nucleaire, IPNS, CEN Cadarache, Saint Paul lez Durance (France); Chopin, J. [Laboratoire d`Electrochimie Inorganique, ENSSPICAM, Marseille (France)

    1996-12-01

    Iodine chemistry is one of the most important subjects of research in the field of reactor safety because this element can form volatile species which represent a biological hazard for environment. As the iodine and the peroxide are both present in the sump of the containment in the event of a severe accident on a light water nuclear reactor, it can be important to improve the knowledge on the reaction of oxidation of iodine by hydrogen peroxide. The kinetics of iodine by hydrogen peroxide has been studied in acid solution using two different analytical methods. The first is a UV/Vis spectrophotometer which records the transmitted intensity at 460 nm as a function of time to follow the decrease of iodine concentration, the second is an amperometric method which permits to record the increase of iodine+1 with time thanks to the current of reduction of iodine+1 to molecular iodine. The iodine was generated by Dushman reaction and the series of investigations were made at 40{sup o}C in a continuous stirring tank reactor. The influence of the initial concentrations of iodine, iodate, hydrogen peroxide, H{sup +} ions has been determined. The kinetics curves comprise two distinct chemical phases both for molecular iodine and for iodine+1. The relative importance of the two processes is connected to the initial concentrations of [I{sub 2}], [IO{sub 3}{sup -}], [H{sub 2}O{sub 2}] and [H{sup +}]. A rate law has been determined for the two steps for molecular iodine. (author) figs., tabs., 22 refs.

  20. Effects of Hydrogen Peroxide on Common Aviation Textiles

    Science.gov (United States)

    2009-08-01

    peroxide has been used for years as a disinfectant in the medical community and is under consideration in the dilute vapor form as a decontaminant... disinfectant /sterilant for transportation vehicles like aircraft, buses, subway trains, ambulances, etc. Although the biological efficacy of STERIS...10-min dip in 35% liquid H2O2 . 13 (a) (b) Figure 15. (a) Vertical and (b) horizontal flammability test results for nylon. 14 (a) (b) Figure 16. (a

  1. Efficiency of hydrogen peroxide in improving disinfection of ICU rooms

    OpenAIRE

    Blazejewski, Caroline; Wallet, Frédéric; Rouzé, Anahita; Le Guern, Rémi; Ponthieux, Sylvie; Salleron, Julia; Nseir, Saad

    2015-01-01

    Introduction The primary objective of this study was to determine the efficiency of hydrogen peroxide (H2O2) techniques in disinfection of ICU rooms contaminated with multidrug-resistant organisms (MDRO) after patient discharge. Secondary objectives included comparison of the efficiency of a vaporizator (HPV, Bioquell®) and an aerosolizer using H2O2, and peracetic acid (aHPP, Anios®) in MDRO environmental disinfection, and assessment of toxicity of these techniques. Methods This prospective c...

  2. Systemic complement activation, lung injury, and products of lipid peroxidation.

    OpenAIRE

    Ward, P. A.; Till, G O; Hatherill, J. R.; Annesley, T M; Kunkel, R G

    1985-01-01

    Previously we have demonstrated that systemic activation of the complement system after intravenous injection of cobra venom factor (CVF) results in acute lung injury as reflected by increases in the vascular permeability of the lung as well as by morphologic evidence of damage to lung vascular endothelial cells. In using the vascular permeability of the lung as the reference, the current studies show a quantitative correlation between lung injury and the appearance in plasma of lipid peroxid...

  3. ALKALINE PEROXIDE MECHANICAL PULPING OF FAST GROWTH PAULOWNIA WOOD

    Directory of Open Access Journals (Sweden)

    Ahmad Jahan Latibari,

    2011-11-01

    Full Text Available Alkaline peroxide mechanical pulping of paulownia wood harvested from exotic tree plantations in northern Iran was investigated. The fiber length, width, and cell wall thickness of this wood were measured as 0.82 mm, 40.3 μm, and 7.1 μm, respectively. The chemical composition including cellulose, lignin, and extractives soluble in ethanol-acetone, 1% NaOH, hot and cold water was determined as 49.5%, 25%, 12.1%, 26.9%, 11.4%, and 8.1% respectively. The ash content of this wood was 0.45%. Pre-washed chips were chemically treated at 70°C for 120 minutes with different combinations of three dosages (1.5, 3, and 4.5% of hydrogen peroxide and three dosages (1.5, 3, and 4.5% of sodium hydroxide prior to defibration. Other chemicals including DTPA, sodium silicate, and MgSO4 were constant at 0.5%, 3%, and 0.5%, respectively. The results showed that using a 1.5% hydrogen peroxide and 4.5% sodium hydroxide charge, the brightness of APMP pulp reached 68.7% ISO and higher chemical dosages did not improve the brightness; however, to produce APMP pulp with higher strength, a sodium hydroxide charge of 4.5% was needed. The tensile strength, tear strength, burst strength indices, and bulk density of the APMP pulp produced from 1.5% hydrogen peroxide and 4.5% sodium hydroxide were measured as 15.5Nm/g, 6.54mN.m2/g, 0.56kPa.m2/g, and 3.47cm3/g, respectively. The resulting pulp was bulky and is suitable for use in the middle layer of boxboard to provide the desired stiffness with a lower basis weight.

  4. Hydrogen peroxide propulsion for smaller satellites (SSC98-VIII-1)

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J C

    1998-07-13

    As satellite designs shrink, providing maneuvering and control capability falls outside the realm of available propulsion technology. While cold gas has been used on the smallest satellites, hydrogen peroxide propellant is suggested as the next step in performance and cost before hydrazine. Minimal toxicity and a small scale enable benchtop propellant preparation and development testing. Progress toward low-cost thrusters and self-pressurizing tank systems is described.

  5. Determination of peracetic acid and hydrogen peroxide in the mixture

    OpenAIRE

    Bodiroga Milanka; Ognjanović Jasminka

    2002-01-01

    Iodometric and permanganometric titrations were used for determination of peracetic acid and hydrogen peroxide (H2O2) in the mixture. Two procedures were described and compared. Titrations could be done in only one vessel, in the same reaction mixture, when iodometric titration of peracetic acid was continued after the permanganometric titration of H2O2, (procedure A). Peracetic acid and H2O2, as oxidizing agents, reacted with potassium iodide in an acid medium, evolving iodine. This reaction...

  6. Levels of oxidative damage and lipid peroxidation in thyroid neoplasia.

    LENUS (Irish Health Repository)

    Young, Orla

    2012-02-01

    BACKGROUND: This study assessed the presence of oxidative damage and lipid peroxidation in thyroid neoplasia. METHODS: Using tissue microarrays and immunohistochemistry, we assessed levels of DNA damage (8-oxo-dG) and lipid peroxidation (4-HNE) in 71 follicular thyroid adenoma (FTA), 45 papillary thyroid carcinoma (PTC), and 17 follicular thyroid carcinoma (FTC) and matched normal thyroid tissue. RESULTS: Cytoplasmic 8-oxo-dG and 4-HNE expression was significantly higher in FTA, FTC, and PTC tissue compared to matched normal tissue (all p values < .001). Similarly, elevated nuclear levels of 8-oxo-dG were seen in all in FTA, FTC, and PTC tissue compared to matched normal (p values < .07, < .001, < .001, respectively). In contrast, a higher level of 4-HNE expression was detected in normal thyroid tissue compared with matched tumor tissue (p < .001 for all groups). Comparing all 3 groups, 4-HNE levels were higher than 8-oxo-dG levels (p < .001 for all groups) except that cytoplasmic levels of 8-oxo-dG were higher than 4-HNE in all (p < .001). These results were independent of proliferation status. CONCLUSION: High levels of DNA damage and lipid peroxidation in benign and malignant thyroid neoplasia indicates this damage is an early event that may influence disease progression.

  7. Enhancing activated-peroxide formulations for porous materials :

    Energy Technology Data Exchange (ETDEWEB)

    Krauter, Paula; Tucker, Mark D.; Tezak, Matthew S.; Boucher, Raymond

    2012-12-01

    During an urban wide-area incident involving the release of a biological warfare agent, the recovery/restoration effort will require extensive resources and will tax the current capabilities of the government and private contractors. In fact, resources may be so limited that decontamination by facility owners/occupants may become necessary and a simple decontamination process and material should be available for this use. One potential process for use by facility owners/occupants would be a liquid sporicidal decontaminant, such as pHamended bleach or activated-peroxide, and simple application devices. While pH-amended bleach is currently the recommended low-tech decontamination solution, a less corrosive and toxic decontaminant is desirable. The objective of this project is to provide an operational assessment of an alternative to chlorine bleach for low-tech decontamination applications activated hydrogen peroxide. This report provides the methods and results for activatedperoxide evaluation experiments. The results suggest that the efficacy of an activated-peroxide decontaminant is similar to pH-amended bleach on many common materials.

  8. ALKALINE PEROXIDE BLEACHING OF HOT WATER TREATED WHEAT STRAW

    Directory of Open Access Journals (Sweden)

    Suvi Mustajoki

    2010-05-01

    Full Text Available The aim of this study was to evaluate the possibilities for chemical consumption reduction in P-P-Paa-P bleaching (P alkaline peroxide stage, Paa peracetic stage of hot water treated straw and the effect of the wheat straw variability on the process. Papermaking fibre production from wheat straw using such a process could be implemented on a small scale if chemical consumption was low enough to eliminate the need for chemical recovery. The pulp properties obtained with this process are equal to or even superior to the properties of wheat straw soda pulp. The possibility of enhancing the first peroxide stage with oxygen and pressure was studied. The possibility for substitution of sodium hydroxide partially with sodium carbonate was also investigated. The objective was to achieve International Standardization Organization (ISO brightness of 75%, with minimal sodium hydroxide consumption, whilst maintaining the pulp properties. The optimization of the peroxide bleaching is challenging if the final brightness target cannot be reduced. Results indicate that up to 25% of the sodium hydroxide could be substituted with sodium carbonate without losing brightness or affecting pulp properties. Another possibility is a mild alkali treatment between the hot water treatment and the bleaching sequence.

  9. Heterogeneous Uptake of Hydrogen Peroxide on Mineral Oxides

    Institute of Scientific and Technical Information of China (English)

    Wei-gang Wang; Mao-fa Ge; Qiao Sun

    2011-01-01

    The interaction of mineral oxides (α-Al2O3,MgO,Fe2O3,and SiO2) with hydrogen peroxide was investigated using the Knudsen cell reactor.The initial reactive uptake coefficients for the commercially available powders are measured as (1.00+0.11)×l0-4 for α-Al2O3,(1.66+0.23) ×10-4 for MgO,(9.70+1.95)×10-5 for Fe2O3,and (5.22+0.9)×10-5 for SiO2.These metal oxide powders exhibit some catalytic behavior toward the decomposition of hydrogen peroxide excluding SiO2.H2O2 can be destroyed on Fe2O3 surface and O2 is formed.The experimental results suggest that the heterogeneous loss on mineral surface can represent an important sink of hydrogen peroxide.

  10. Flow injection analysis of organic peroxide explosives using acid degradation and chemiluminescent detection of released hydrogen peroxide.

    Science.gov (United States)

    Mahbub, Parvez; Zakaria, Philip; Guijt, Rosanne; Macka, Mirek; Dicinoski, Greg; Breadmore, Michael; Nesterenko, Pavel N

    2015-10-01

    The applicability of acid degradation of organic peroxides into hydrogen peroxide in a pneumatically driven flow injection system with chemiluminescence reaction with luminol and Cu(2+) as a catalyst (FIA-CL) was investigated for the fast and sensitive detection of organic peroxide explosives (OPEs). The target OPEs included hexamethylene triperoxide diamine (HMTD), triacetone triperoxide (TATP) and methylethyl ketone peroxide (MEKP). Under optimised conditions maximum degradations of 70% and 54% for TATP and HMTD, respectively were achieved at 162 µL min(-1), and 9% degradation for MEKP at 180 µL min(-1). Flow rates were precisely controlled in this single source pneumatic pressure driven multi-channel FIA system by model experiments on mixing of easily detectable component solutions. The linear range for detection of TATP, HMTD and H2O2 was 1-200 µM (r(2)=0.98-0.99) at both flow rates, while that for MEKP was 20-200 µM (r(2)=0.97) at 180 µL min(-1). The detection limits (LODs) obtained were 0.5 µM for TATP, HMTD and H2O2 and 10 µM for MEKP. The detection times varied from 1.5 to 3 min in this FIA-CL system. Whilst the LOD for H2O2 was comparable with those reported by other investigators, the LODs and analysis times for TATP and HMTD were superior, and significantly, this is the first time the detection of MEKP has been reported by FIA-CL.

  11. Drug efficiency of 18 % benzoyl propiconazole WG against rice sheath blight in field trials%18%苯甲·丙环唑WG防治水稻纹枯病的田间药效试验

    Institute of Scientific and Technical Information of China (English)

    陈建成; 张世平

    2012-01-01

    A field trial of drug efficiency using 18% benzoyl propiconazole WG against rice sheath blight was carried out. The results showed that the control efficiency of 18% benzoyl propiconazole WG with the dosages of 30 g, 40 g and 50 g per 667 m^2 was 78.68%, 80.08% and 84.36%, respectively, in the fifteenth day after the second medication. The dosages of 50 g and 40 g had good control efficiency (84.36% and 80.08%, respectively) and had no bad effect on the growth of crops, safety after treating. It also had no harmfull effect on the other organism, insects and non-target organism. In the pro- duction practice, it was suggested that to control rice sheath blight by using 18% benzoyl propiconazole WG with dosages of 40-50 g per 667 m^2, the pesticide was applied at peak of rice tillering stage.%进行18%苯甲·丙环唑WG防治水稻纹枯病的药效试验,结果表明:每667m。使用18%苯甲·丙环唑WG30、40、50g第2次药后15d对水稻纹枯病的防效分别为78.68%、80.08%和84.36%;每667m。使用18%苯甲·丙环唑WG50g及40g的防效较高,且对作物生长无不良的影响,药后较安全,对其他生物、其他病虫害及其他非靶标生物均无影响。生产上建议每667m。使用18%苯甲·丙环唑WG40—50g(制剂量)防治水稻纹枯病,于水稻分蘖盛期施药。

  12. Interaction of (4-hydroxyphenyl)pyruvate dioxygenase with the specific inhibitor 2-[2-nitro-4-(trifluoromethyl)benzoyl]-1,3-cyclohexanedione.

    Science.gov (United States)

    Kavana, Michael; Moran, Graham R

    2003-09-01

    (4-Hydroxyphenyl)pyruvate dioxygenase (HPPD) is a non-heme Fe(II) enzyme that catalyzes the conversion of (4-hydroxyphenyl)pyruvate (HPP) to homogentisate as part of the tyrosine catabolism pathway. Inhibition of HPPD by the triketone 2-[2-nitro-4-(trifluoromethyl)benzoyl]-1,3-cyclohexanedione (NTBC) is used to treat type I tyrosinemia, a rare but fatal defect in tyrosine catabolism. Although triketones have been used for many years as HPPD inhibitors for both medical and herbicidal purposes, the mechanism of inhibition is not well understood. The following work provides mechanistic insight into NTBC binding. The tautomeric population of NTBC in aqueous solution is dominated by a single enol as determined by NMR spectroscopy. NTBC preferentially binds to the complex of HPPD and FeII [HPPD.Fe(II)] as evidenced by a visible absorbance feature centered at 450 nm. The binding of NTBC to HPPD.Fe(II) was observed using a rapid mixing method and was shown to occur in two phases and comprise three steps. A hyperbolic dependence of the first observable process with NTBC concentration indicates a pre-equilibrium binding step followed by a limiting rate (K(1) = 1.25 +/- 0.08 mM, k(2) = 8.2 +/- 0.2 s(-1)), while the second phase (k(3) = 0.76 +/- 0.02 s(-1)) had no dependence on NTBC concentration. Neither K(1),k(2), nor k(3) was influenced by pH in the range of 6.0-8.0. Isotope effects on both k(2) and k(3) were observed when D(2)O is used as the solvent (for k(2), k(h)/k(d) = 1.3; for k(3), k(h)/k(d) = 3.2). It is therefore proposed that the bidentate association of NTBC with the active site metal ion (k(2)) precedes the Lewis acid-assisted conversion of the bound enol to the enolate (k(3)). Although the native enzyme without substrate reacts with molecular oxygen to form the oxidized holoenzyme, the HPPD.Fe(II).NTBC complex does not. When the complex is exposed to atmospheric oxygen, the absorbance feature associated with NTBC binding does not diminish over the course of 2

  13. Methods to create thermally oxidized lipids and comparison of analytical procedures to characterize peroxidation.

    Science.gov (United States)

    Liu, P; Kerr, B J; Chen, C; Weber, T E; Johnston, L J; Shurson, G C

    2014-07-01

    The objective of this experiment was to evaluate peroxidation in 4 lipids, each with 3 levels of peroxidation. Lipid sources were corn oil (CN), canola oil (CA), poultry fat, and tallow. Peroxidation levels were original lipids (OL), slow-oxidized lipids (SO), and rapid-oxidized lipids (RO). To produce peroxidized lipids, OL were either heated at 95°C for 72 h to produce SO or heated at 185°C for 7 h to produce RO. Five indicative measurements (peroxide value [PV], p-anisidine value [AnV], thiobarbituric acid reactive substances [TBARS] concentration, hexanal concentration, 4-hydroxynonenal [HNE] concentration, and 2,4-decadienal [DDE]) and 2 predictive tests (active oxygen method [AOM] stability and oxidative stability index [OSI]) were performed to quantify the level of oxidation of the subsequent 12 lipids with varying levels of peroxidation. Analysis showed that a high PV accurately indicated the high level of lipid peroxidation, but a moderate or low PV may be misleading due to the unstable characteristics of hydroperoxides as indicated by the unchanged PV of rapidly oxidized CN and CA compared to their original state (OL). However, additional tests, which measure secondary peroxidation products such as AnV, TBARS, hexanal, HNE, and DDE, may provide a better indication of lipid peroxidation than PV for lipids subjected to a high level of peroxidation. Similar to PV analysis, these tests may also not provide irrefutable information regarding the extent of peroxidation because of the volatile characteristics of secondary peroxidation products and the changing stage of lipid peroxidation. For the predictive tests, AOM accurately reflected the increased lipid peroxidation caused by SO and RO as indicated by the increased AOM value in CN and CA but not in poultry fat and tallow, which indicated a potential disadvantage of the AOM test. Oxidative stability index successfully showed the increased lipid peroxidation caused by SO and RO in all lipids, but it too may

  14. An Investigation into the Effect of Stabiliser Content on the Minimum Characteristic Chamber Length for Homogeneously-Catalysed Hydrogen Peroxide

    Science.gov (United States)

    2007-11-02

    rate. 15. SUBJECT TERMS Hydrogen peroxide, high test peroxide, HTP , rocket grade hydrogen peroxide, RGHP, stabilized hydrogen...homogeneous catalytic decomposition of hydrogen peroxide (often referred to as ’high test peroxide’, or HTP - here used in a general sense to...207< Tc < 516 deg C, depending on the HTP concentration. 3. THE TEST RIG DELTACAT Ltd runs a small test -site in Hampshire, England. Recently

  15. Bis(4-benzoyl-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-olato-κ2O,O′(methanol-κOdioxidouranium(VI methanol monosolvate

    Directory of Open Access Journals (Sweden)

    Ouarda Dehbi

    2012-04-01

    Full Text Available In the title compound, [U(C17H13N2O22O2(CH3OH]·CH3OH, the UVI ion is coordinated by seven O atoms in a distorted pentagonal–bipyramidal geometry with two 3-methyl-1-phenyl-4-benzoyl-4,5-dihydro-1H-pyrazol-5-olate groups with two O atoms in a bidentate chelating coordination mode and by three O atoms, one of which is from a methanol ligand. The crystal packing can be described by alternating layers of complex molecules along the a axis. The structure is stabilized by O—H...N and O—H...O hydrogen bonding and van der Waals interactions.

  16. (3-Benzoyl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-olato-κ2O,Obis[2-(2-pyridylphenyl-κ2C1,N]iridium(III

    Directory of Open Access Journals (Sweden)

    Kaijun Luo

    2011-11-01

    Full Text Available The title compound, [Ir(C11H8N2(C17H19O2], has an octahedral coordination geometry around the IrIII atom, retaining the cis-C,C,trans–N,N chelate disposition of the two 2-phenylpyridine ligands. The chelate rings are nearly mutually perpendicular [the interplanar angles range from 85.48 (17 to 89.17 (19°]. The two 2-(2-pyridylphenyl ligands are approximately planar, with the plane of the phenyl ring being inclined to that of the pyridine ring by 2.3 (3 and 5.1 (3° in the two ligands. The interplanar angle between the phenyl ring in 3-benzoyl-camphor and the IrO2C3 chelate ring is 35.5 (2°.

  17. Solid State Structure and Solution Thermodynamics of Three-Centered Hydrogen Bonds (O∙∙∙H∙∙∙O Using N-(2-Benzoyl-phenyl Oxalyl Derivatives as Model Compounds

    Directory of Open Access Journals (Sweden)

    Carlos Z. Gómez-Castro

    2014-09-01

    Full Text Available Intramolecular hydrogen bond (HB formation was analyzed in the model compounds N-(2-benzoylphenylacetamide, N-(2-benzoylphenyloxalamate and N1,N2-bis(2-benzoylphenyloxalamide. The formation of three-center hydrogen bonds in oxalyl derivatives was demonstrated in the solid state by the X-ray diffraction analysis of the geometric parameters associated with the molecular structures. The solvent effect on the chemical shift of H6 [δH6(DMSO-d6–δH6(CDCl3] and Δδ(ΝΗ/ΔT measurements, in DMSO-d6 as solvent, have been used to establish the energetics associated with intramolecular hydrogen bonding. Two center intramolecular HB is not allowed in N-(2-benzoylphenylacetamide either in the solid state or in DMSO-d6 solution because of the unfavorable steric effects of the o-benzoyl group. The estimated ΔHº and ΔSº values for the hydrogen bonding disruption by DMSO-d6 of 28.3(0.1 kJ·mol−1 and 69.1(0.4 J·mol−1·K−1 for oxalamide, are in agreement with intramolecular three-center hydrogen bonding in solution. In the solid, the benzoyl group contributes to develop 1-D and 2-D crystal networks, through C–H∙∙∙A (A = O, π and dipolar C=O∙∙∙A (A = CO, π interactions, in oxalyl derivatives. To the best of our knowledge, this is the first example where three-center hydrogen bond is claimed to overcome steric constraints.

  18. BIOSORPTION OF CONGO RED BY HYDROGEN PEROXIDE TREATED TENDU WASTE

    Directory of Open Access Journals (Sweden)

    G. K. Nagda ، V. S. Ghole

    2009-07-01

    Full Text Available Solid wastes from agro-industrial operations can be recycled as non-conventional adsorbents if they are inert and harmless and reduce the cost of wastewater treatment. Tendu leaf Diospyros melanoxylon is the second largest forest product in India after timber and is exclusively used in making local cigarette called Bidi. Waste leaf cutting remaining after making cigarette was used in present study as a biosorbent for the removal of Congo red dye from aqueous solution. It was treated with hydrogen peroxide to obtain biosorbent with increased adsorption capacity. Batch type experiments were conducted to study the influence of different parameters such as pH, initial dye concentration and dosage of adsorbent on biosorption evaluated. The adsorption occured very fast initially and attains equilibrium within 60 min at pH= 6.2 and the equilibrium attained faster after hydrogen peroxide modification. Kinetic studies showed that the biosorption of Congo red on tendu waste followed pseudo-second-order rate equation. The data fitted well to Langmuir and Freundlich isotherm models. Comparison was done on the extent of biosorption between untreated and treated forms of the tendu waste. The maximum adsorption capacity for untreated tendu waste was found to be 46.95 mg/g, which was enhanced by 2.8 times after hydrogen peroxide treatment and was found to be 134.4 mg/g. The adsorption process was in conformity with Freundlich and Langmuir isotherms for Congo red adsorption from aqueous solution. The study demonstrated use of milder chemical treatment of tendu waste to obtain a biosorbent with enhanced dye removal capacity.

  19. Efficacy of hydrogen peroxide for treating saprolegniasis in channel catfish

    Science.gov (United States)

    Howe, G.E.; Gingerich, W.H.; Dawson, V.K.; Olson, J.J.

    1999-01-01

    Hatchery-reared fish and their eggs are commonly afflicted with saprolegniasis, a fungal disease that can cause significant losses in production. Fish culturists need safe and effective fungicides to minimize losses and meet production demands. The efficacy of hydrogen peroxide was evaluated for preventing or controlling mortality associated with saprolegniasis in channel catfish Ictalurus punctatus. Saprolegniasis was systematically induced in channel catfish so various therapies could be evaluated in a controlled laboratory environment. Both prophylactic and therapeutic hydrogen peroxide bath treatments of 50, 100, and 150 ??L/L for 1 h were administered every other day for seven total treatments. All untreated positive control fish died of saprolegniasis during the prophylactic and therapeutic tests. Hydrogen peroxide treatments of 150 ??L/L were harmful (relative to lower concentrations) to test fish and resulted in 73-95% mortality. Mortality was attributed to a combination of abrasion, temperature, chemical treatment, and disease stressors. Treatments of 100 ??L/L were less harmful (relatively) but also appeared to contribute to mortality (60-79%). These treatments, however, significantly reduced the incidence of mortality and infection compared with those observed for fish of the positive control or 150-??L/L treatment groups. Overall, treatments of 50 ??L/L were found to be the most safe and effective of those tested. Mortality with this concentration ranged from 16% in therapeutic tests to 41% in prophylactic tests. The statistical model employed estimated that the optimum treatment concentration for preventing or controlling mortality, reducing the incidence of infections, and enhancing the recovery of infected fish was 75 ??L H2O2/L.

  20. Vapor hydrogen peroxide as alternative to dry heat microbial reduction

    Science.gov (United States)

    Chung, S.; Kern, R.; Koukol, R.; Barengoltz, J.; Cash, H.

    2008-09-01

    The Jet Propulsion Laboratory (JPL), in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal was to include this technique, with an appropriate specification, in NASA Procedural Requirements 8020.12 as a low-temperature complementary technique to the dry heat sterilization process. The VHP process is widely used by the medical industry to sterilize surgical instruments and biomedical devices, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal for this study was to determine the minimum VHP process conditions for planetary protection acceptable microbial reduction levels. Experiments were conducted by the STERIS Corporation, under contract to JPL, to evaluate the effectiveness of vapor hydrogen peroxide for the inactivation of the standard spore challenge, Geobacillus stearothermophilus. VHP process parameters were determined that provide significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters of interest: hydrogen peroxide concentration, number of injection cycles, and exposure duration, the investigation also considered the possible effect on lethality of environmental parameters: temperature, absolute humidity, and material substrate. This study delineated a range of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D-value may be imposed, a process humidity range for which the worst case D-value may be imposed, and the dependence on selected spacecraft material substrates. The derivation of D-values from the lethality data permitted conservative planetary protection recommendations.

  1. Optical sensing of peroxide using ceria nanoparticles via fluorescence quenching technique

    Science.gov (United States)

    Shehata, Nader; Samir, Effat; Gaballah, Soha; Salah, Mohammed

    2016-07-01

    This study introduces the application of ceria nanoparticles (NPs) as an optical sensor for peroxide using fluorescence quenching technique. Our synthesized ceria NPs have the ability to adsorb peroxides via its oxygen vacancies. Ceria NPs solution with added variable concentrations of hydrogen peroxides is exposed through near-UV excitation and the detected visible fluorescent emission is found to be at ˜520 nm. The fluorescent intensity peak is found to be reduced with increasing the peroxide concentrations due to static fluorescence quenching technique. The relative intensity change of the visible fluorescent emission has been reduced to more than 50% at added peroxide concentrations up to 10 wt. %. In order to increase ceria peroxides sensing sensitivity, lanthanide elements such as samarium (Sm) are used as ceria NPs dopant. This research work could be applied further in optical sensors of radicals in biomedical engineering and environmental monitoring.

  2. Lipid peroxidation of plants under microgravity and its simulation

    Science.gov (United States)

    Zhadko, S. I.; Polulyakh, Yu. A.; Vorobyeva, T. V.; Baraboy, V. A.

    1994-08-01

    In series of space experiments a board the biosatellites ``Cosmos 1887'', ``Bion 9'', the orbital stations ``Salut'', ``Mir'' and under clinostating, changes of lipid peroxidation (LPO) and antioxidation activity (AOA) of Chlorella, Haplopappus tissue culture, wheat and pea roots were determined. The changes had a complex fluctuation character three steps of response were established; LPO decreasing accompanied by AOA increase; stabilization LPO⇄AOA balance; secondary LPO activation. Most early and highly amplitude decreasing of LPO were fixed in mitochondria. The rate of response have been increased on multicellular level of plants organization.

  3. HYDROGEN PEROXIDE BLEACHING OF CMP PULP USING MAGNESIUM HYDROXIDE

    Directory of Open Access Journals (Sweden)

    Farhad Zeinaly

    2009-11-01

    Full Text Available Conventional bleaching of hardwood CMP pulp with magnesium hydroxide (Mg(OH2 show significant benefits over bleaching with sodium hydroxide (NaOH under various conditions. Magnesium hydroxide bleaching generate higher optical properties, higher pulp yield and lower effluent COD at the same chemical charge, but the physical properties were found to be similar for both processes. The initial freeness of the bleached pulps and refining value to reach a target freeness (about 350 ml. CSF were more for the Mg(OH2-based process. The residual peroxide of filtrate from the Mg(OH2-based process was very high as compared to conventional bleaching.

  4. Direct synthesis of hydrogen peroxide from plasma-water interactions

    OpenAIRE

    Jiandi Liu; Bangbang He; Qiang Chen; Junshuai Li; Qing Xiong; Guanghui Yue; Xianhui Zhang; Size Yang; Hai Liu; Qing Huo Liu

    2016-01-01

    Hydrogen peroxide (H2O2) is usually considered to be an important reagent in green chemistry since water is the only by-product in H2O2 involved oxidation reactions. Early studies show that direct synthesis of H2O2 by plasma-water interactions is possible, while the factors affecting the H2O2 production in this method remain unclear. Herein, we present a study on the H2O2 synthesis by atmospheric pressure plasma-water interactions. The results indicate that the most important factors for the ...

  5. Hydrogen peroxide-based propulsion and power systems.

    Energy Technology Data Exchange (ETDEWEB)

    Melof, Brian Matthew; Keese, David L.; Ingram, Brian V.; Grubelich, Mark Charles; Ruffner, Judith Alison; Escapule, William Rusty

    2004-04-01

    Less toxic, storable, hypergolic propellants are desired to replace nitrogen tetroxide (NTO) and hydrazine in certain applications. Hydrogen peroxide is a very attractive replacement oxidizer, but finding acceptable replacement fuels is more challenging. The focus of this investigation is to find fuels that have short hypergolic ignition delays, high specific impulse, and desirable storage properties. The resulting hypergolic fuel/oxidizer combination would be highly desirable for virtually any high energy-density applications such as small but powerful gas generating systems, attitude control motors, or main propulsion. These systems would be implemented on platforms ranging from guided bombs to replacement of environmentally unfriendly existing systems to manned space vehicles.

  6. 4-Hydroxy-nonenal—A Bioactive Lipid Peroxidation Product

    Directory of Open Access Journals (Sweden)

    Rudolf J. Schaur

    2015-09-01

    Full Text Available This review on recent research advances of the lipid peroxidation product 4-hydroxy-nonenal (HNE has four major topics: I. the formation of HNE in various organs and tissues, II. the diverse biochemical reactions with Michael adduct formation as the most prominent one, III. the endogenous targets of HNE, primarily peptides and proteins (here the mechanisms of covalent adduct formation are described and the (patho- physiological consequences discussed, and IV. the metabolism of HNE leading to a great number of degradation products, some of which are excreted in urine and may serve as non-invasive biomarkers of oxidative stress.

  7. Combustion Characteristics of Nanoaluminum, Liquid Water, and Hydrogen Peroxide Mixtures

    Science.gov (United States)

    2008-01-01

    test peroxide ( HTP , 85% H2O2) as the oxidizer [22– 26]. Problems with the use of H2O2 systems include its sensitivity to shock and its tendency to...reported that the mix- ture would not self-deflagrate without the addition of the thickening agent into the mixture. At their maximum test pressure, 7...A pycnometer test determined particle density to be 3.205 g/cm3, which is inclusive of the oxide passiva- tion layer (∼3.97 g/cm3), which explains

  8. Petroleum Contaminated Soil Treatment Using Surfactant and Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Ilza Lobo

    2010-12-01

    Full Text Available The process of washing soil with surfactants, sodium lauryl ether sulphate (LESS and sodium lauryl sulphate (SDS was combined with chemical oxidation using hydrogen peroxide, with a view to in situ remediation of clay soil contaminated with hydrocarbons oil. The evaluation of the efficiency of the procedure was the removal of polyaromatic hydrocarbons and the comparison of physical and chemical characteristics of contaminated soil and uncontaminated from the same region. The combination of these two techniques, soil washing and application of an oxidizing agent, presented as a process of effective remediation for soils contaminated with petroleum products in subtropical regions.

  9. Detection of hydrogen peroxide by lactoperoxidase-mediated dityrosine formation.

    Science.gov (United States)

    Donkó, Agnes; Orient, Anna; Szabó, Pál T; Németh, Gábor; Vántus, Tibor; Kéri, György; Orfi, László; Hunyady, László; Buday, László; Geiszt, Miklós

    2009-05-01

    The aim of this work was to study the dityrosine-forming activity of lactoperoxidase (LPO) and its potential application for measuring hydrogen peroxide (H2O2). It was observed that LPO was able to form dityrosine at low H2O2 concentrations. Since dityrosine concentration could be measured in a simple fluorimetric reaction, this activity of the enzyme was utilized for the measurement of H2O2 production in different systems. These experiments successfully measured the activity of NADPH oxidase 4 (Nox4) by this method. It was concluded that LPO-mediated dityrosine formation offers a simple way for H2O2 measurement.

  10. [Influence of ethanol and ethanol-induced lipid peroxidation on the steroidogenic activity of testicles].

    Science.gov (United States)

    Kashko, M F; Khokha, A M; Antsulevich, S N; Doroshkevich, N A; Voronov, P P

    1993-01-01

    Chronic alcohol intoxication results in the diminished testosterone level and activation of lipid peroxidation in rat testes. A significant decrease in 3 beta-hydroxysteroid-hydrogenase and 17-dehydrogenase activity has been observed in microsomes. Analogous shifts have been evoked in vitro by the induction of lipid peroxidation in microsomes. That permitted one to suppose that alcohol-induced alterations in tests are partially mediated by induction of lipid peroxidation.

  11. Mechanisms involved in the modulation of astroglial resistance to oxidative stress induced by activated microglia: antioxidative systems, peroxide elimination, radical generation, lipid peroxidation.

    Science.gov (United States)

    Röhl, Claudia; Armbrust, Elisabeth; Herbst, Eva; Jess, Anne; Gülden, Michael; Maser, Edmund; Rimbach, Gerald; Bösch-Saadatmandi, Christine

    2010-05-01

    Microglia and astrocytes are the cellular key players in many neurological disorders associated with oxidative stress and neuroinflammation. Previously, we have shown that microglia activated by lipopolysaccharides (LPS) induce the expression of antioxidative enzymes in astrocytes and render them more resistant to hydrogen peroxide (H2O2). In this study, we examined the mechanisms involved with respect to the cellular action of different peroxides, the ability to detoxify peroxides, and the status of further antioxidative systems. Astrocytes were treated for 3 days with medium conditioned by purified quiescent (microglia-conditioned medium, MCM[-]) or LPS-activated (MCM[+]) microglia. MCM[+] reduced the cytotoxicity of the organic cumene hydroperoxide in addition to that of H2O2. Increased peroxide resistance was not accompanied by an improved ability of astrocytes to remove H2O2 or an increased expression/activity of peroxide eliminating antioxidative enzymes. Neither peroxide-induced radical generation nor lipid peroxidation were selectively affected in MCM[+] treated astrocytes. The glutathione content of peroxide resistant astrocytes, however, was increased and superoxide dismutase and heme oxygenase were found to be upregulated. These changes are likely to contribute to the higher peroxide resistance of MCM[+] treated astrocytes by improving their ability to detoxify reactive oxygen radicals and oxidation products. For C6 astroglioma cells a protective effect of microglia-derived factors could not be observed, underlining the difference of primary cells and cell lines concerning their mechanisms of oxidative stress resistance. Our results indicate the importance of microglial-astroglial cell interactions during neuroinflammatory processes.

  12. [Activation of lipid peroxidation in the adrenal cortex by metal ions].

    Science.gov (United States)

    Doroshkevich, N A; Antsulevich, S N; Vinogradov, V V

    1988-01-01

    The processes of lipid peroxidation have been studied in bovine adrenal cortex in vitro. The lipid peroxidation rate in this tissue is shown to be dependent on the content of metal ions. EDTA, deferroxamine and penicyllamine inhibit spontaneous lipid peroxidation by 25, 50 and 42%, respectively. The ability to activate the process permits arranging metal ions in the following sequence: Fe2+ greater than Fe3+ greater than Cu2+ greater than Mg2+ greater than Mn2+. The maximum activation of lipid peroxidation is observed at Fe2+ and Fe3+ concentrations within the range of 5 x 10(-6) x 10(-4) M.

  13. Catalyst-free activation of peroxides under visible LED light irradiation through photoexcitation pathway.

    Science.gov (United States)

    Gao, Yaowen; Li, Yixi; Yao, Linyu; Li, Simiao; Liu, Jin; Zhang, Hui

    2017-05-05

    Catalysts are known to activate peroxides to generate active radicals (i.e., hydroxyl radical (OH) and sulfate radical (SO4(-))) under certain conditions, but the activation of peroxides in the absence of catalysts under visible light irradiation has been rarely reported. This work demonstrates a catalyst-free activation of peroxides for the generation of OH and/or SO4(-) through photoexcited electron transfer from organic dyes to peroxides under visible LED light irradiation, where Rhodamine B (RhB) and Eosin Y (EY) were selected as model dyes. The formation of OH and/or SO4(-) in the reactions and the electron transfer from the excited dyes to peroxides were validated via electron paramagnetic resonance (EPR), photoluminescence (PL) spectra and cyclic voltammetry (CV). The performance of the peroxide/dye/Vis process was demonstrated to be altered depending on the target substrate. Meanwhile, the peroxide/dye/Vis process was effective for simultaneous decolorization of dyes and production of active radicals under neutral even or basic conditions. The findings of this study clarified a novel photoexcitation pathway for catalyst-free activation of peroxides under visible light irradiation, which could avoid the secondary metal ion (dissolved or leached) pollution from the metal-based catalysts and expand the application range of the peroxide-based catalytic process.

  14. Antioxidant action of Moringa oleifera Lam. (drumstick) against antitubercular drugs induced lipid peroxidation in rats.

    Science.gov (United States)

    Ashok Kumar, N; Pari, L

    2003-01-01

    The protective effect of Moringa oleifera Lam. (Moringaceae) on hepatic marker enzymes, lipid peroxidation, and antioxidants was investigated during antitubercular drug (isoniazid, rifampicin, and pyrazinamide)-induced toxicity in rats. Enhanced hepatic marker enzymes and lipid peroxidation of antitubercular drug treatment was accompanied by a significant decrease in the levels of vitamin C, reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase. Administration of Moringa oleifera extract and silymarin significantly decreased hepatic marker enzymes and lipid peroxidation with a simultaneous increase in the level of antioxidants. We speculate that Moringa oleifera extract exerts its protective effects by decreasing liver lipid peroxides and enhancing antioxidants.

  15. ALKALINE PEROXIDE MECHANICAL PULPING OF NOVEL BRAZILIAN EUCALYPTUS HYBRIDS

    Directory of Open Access Journals (Sweden)

    Marcelo Coelho dos Santos Muguet,

    2012-07-01

    Full Text Available Eucalyptus wood is among the most important biomass resource in the world. Wood mechanical defibration and fibrillation are energy-intensive processes utilized not only to produce pulp for papermaking, but also to produce reinforcement fibers for biocomposites, nanocellulose, or pretreat lignocellulosic material for biofuels production. The structural features of different Eucalyptus hybrids affecting the refining energy consumption and produced fiber furnish properties were evaluated. The defibration and fiber development were performed using an alkaline peroxide mechanical pulping (APMP process, which included chelation followed by an alkaline peroxide treatment prior to wood chip defibration. Despite the similar wood densities and chemical compositions of different Eucalyptus hybrids, there was a clear difference in the extent of defibration and fibrillation among the hybrids. The high energy consumption was related to a high amount of guaiacyl lignin. This observation is of major importance when considering the optimal wood hybrids for mechanical wood defibration and for understanding the fundamental phenomena taking place in chemi-mechanical defibration of wood.

  16. Role of dyslipidaemia and lipid peroxidation in pregnancy induced hypertension

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    Saxena S

    2015-07-01

    Full Text Available Background: Pregnancy induced hypertension (PIH contributes greatly to maternal morbidity and mortality. Altered lipid profile and increased lipid peroxidation activate endothelial dysfunction and atherothrombosis leading to PIH. Therefore, estimation of lipid profile with serum malondialdehyde (MDA in pregnancy may be helpful in predicting the development of PIH and further progression. Material and methods: In this prospective case-control study, serum lipid profile and MDA were estimated in 70 PIH subjects with gestational hypertension, pre-eclampsia, eclampsia; and 70 normotensive pregnant women aged 18 - 40 years, with gestational age of over 20 weeks. Results: A statistically significant higher serum total cholesterol, very low density lipoprotein cholesterol (VLDL-C, low density lipoprotein cholesterol (LDL-C, triglycerides (TG, TC/HDL-C, LDL-C/HDL-C and MDA, and a significantly lower HDL-C was noted in PIH subjects as compared to control subjects. When compared with the severity of PIH, all the lipoproteins (except HDL-C along with MDA were found to be higher in women with eclampsia when compared with gestational hypertension, pre-eclampsia and normotensive pregnant women. Conclusions: An abnormal lipid metabolism along with oxidative stress may add to the promotion of vascular dysfunction leading to PIH. Lipoproteins and MDA alter significantly in eclampsia. Therefore, during pregnancy, early diagnosis and management of dyslipidaemia may prevent lipid peroxidation and progression of PIH thereby preventing obstetric complications.

  17. Hydrogen Peroxide and Sodium Transport in the Lung and Kidney

    Directory of Open Access Journals (Sweden)

    V. Shlyonsky

    2016-01-01

    Full Text Available Renal and lung epithelial cells are exposed to some significant concentrations of H2O2. In urine it may reach 100 μM, while in the epithelial lining fluid in the lung it is estimated to be in micromolar to tens-micromolar range. Hydrogen peroxide has a stimulatory action on the epithelial sodium channel (ENaC single-channel activity. It also increases stability of the channel at the membrane and slows down the transcription of the ENaC subunits. The expression and the activity of the channel may be inhibited in some other, likely higher, oxidative states of the cell. This review discusses the role and the origin of H2O2 in the lung and kidney. Concentration-dependent effects of hydrogen peroxide on ENaC and the mechanisms of its action have been summarized. This review also describes outlooks for future investigations linking oxidative stress, epithelial sodium transport, and lung and kidney function.

  18. INTERACTION OF ALDEHYDES DERIVED FROM LIPID PEROXIDATION AND MEMBRANE PROTEINS.

    Directory of Open Access Journals (Sweden)

    Stefania ePizzimenti

    2013-09-01

    Full Text Available A great variety of compounds are formed during lipid peroxidation of polyunsaturated fatty acids of membrane phospholipids. Among them, bioactive aldehydes, such as 4-hydroxyalkenals, malondialdehyde (MDA and acrolein, have received particular attention since they have been considered as toxic messengers that can propagate and amplify oxidative injury. In the 4-hydroxyalkenal class, 4-hydroxy-2-nonenal (HNE is the most intensively studied aldehyde, in relation not only to its toxic function, but also to its physiological role. Indeed, HNE can be found at low concentrations in human tissues and plasma and participates in the control of biological processes, such as signal transduction, cell proliferation and differentiation. Moreover, at low doses, HNE exerts an anti-cancer effect, by inhibiting cell proliferation, angiogenesis, cell adhesion and by inducing differentiation and/or apoptosis in various tumor cell lines. It is very likely that a substantial fraction of the effects observed in cellular responses, induced by HNE and related aldehydes, be mediated by their interaction with proteins, resulting in the formation of covalent adducts or in the modulation of their expression and/or activity. In this review we focus on membrane proteins affected by lipid peroxidation-derived aldehydes, under physiological and pathological conditions.

  19. Thermal Hazard Evaluation of Lauroyl Peroxide Mixed with Nitric Acid

    Directory of Open Access Journals (Sweden)

    Chi-Min Shu

    2012-07-01

    Full Text Available Many thermal runaway incidents have been caused by organic peroxides due to the peroxy group, –O–O–, which is essentially unstable and active. Lauroyl peroxide (LPO is also sensitive to thermal sources and is incompatible with many materials, such as acids, bases, metals, and ions. From the thermal decomposition reaction of various concentrations of nitric acid (HNO3 (from lower to higher concentrations with LPO, experimental data were obtained as to its exothermic onset temperature (T0, heat of decomposition (ΔHd, isothermal time to maximum rate (TMRiso, and other safety parameters exclusively for loss prevention of runaway reactions and thermal explosions. As a novel finding, LPO mixed with HNO3 can produce the detonation product of 1-nitrododecane. We used differential scanning calorimetry (DSC, thermal activity monitor III (TAM III, and gas chromatography/mass spectrometer (GC/MS analyses of the reactivity for LPO and itself mixed with HNO3 to corroborate the decomposition reactions and reaction mechanisms in these investigations.

  20. Photodecomposition of hydrogen peroxide in highly saline aqueous medium

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    A. J. Luna

    2006-09-01

    Full Text Available The photodecomposition of hydrogen peroxide was performed in highly saline aqueous medium (60 g.L-1 of NaCl. The Fe3+/H2O2/NaCl/UV system was tested at temperatures from 20 to 50 ºC, while the intervals of concentration of Fe3+ and H2O2 were 1 to 2.5 mM and 230 to 630 mM, respectively. It is known from the literature that chloride is an inhibitor of the oxidation of organic compound in aqueous medium, but this effect has not been observed to be expressive for hydrogen peroxide. Despite this result, experiments were conducted in presence of high concentration of salt (60 g.L-1, emulating the agrochemical process condition. The series of measurements has been evaluated and correlated. Thermal and photochemical dependencies were described satisfactorily by a simplified kinetic model. The apparent activation energy was estimated to be 27.6 kJ.mol-1.

  1. Determination of peracetic acid and hydrogen peroxide in the mixture

    Directory of Open Access Journals (Sweden)

    Bodiroga Milanka

    2002-01-01

    Full Text Available Iodometric and permanganometric titrations were used for determination of peracetic acid and hydrogen peroxide (H2O2 in the mixture. Two procedures were described and compared. Titrations could be done in only one vessel, in the same reaction mixture, when iodometric titration of peracetic acid was continued after the permanganometric titration of H2O2, (procedure A. Peracetic acid and H2O2, as oxidizing agents, reacted with potassium iodide in an acid medium, evolving iodine. This reaction was used for the quantitative iodometric determination of total peroxide in procedure B. H2O2 reacted with potassium permanganate in acid medium, but peracetic acid did not react under the same conditions. That made possible the selective permanganometric determination of H2O2 in the presence of peracetic acid. The procedure B was performed in two titration vessels (KV=3.4% for peracetic acid, 0.6% for H2O2. The procedure A for iodometric determination of peracetic acid in one titration vessel after permanganometric titration of H2O2 was recommended (KV=2,5% for peracetic acid, 0,45% for H2O2.

  2. Effect of Hydrogen Peroxide on the Antibacterial Substantivity of Chlorhexidine

    Directory of Open Access Journals (Sweden)

    Shahriar Shahriari

    2010-01-01

    Full Text Available The purpose of this in vitro study was to assess the effect of hydrogen peroxide on the antibacterial substantivity of chlorhexidine (CHX. Seventy-five dentine tubes prepared from human maxillary central and lateral incisor teeth were used. After contamination with Enterococcus faecalis for 14 days, the specimens were divided into five groups as follows: CHX, H2O2, CHX + H2O2, infected dentine tubes (positive control, and sterile dentine tubes (negative control. Dentine chips were collected with round burs into tryptic soy broth, and after culturing, the number of colony-forming units (CFU was counted. The number of CFU was minimum in the first cultures in all experimental groups, and the results obtained were significantly different from each other at any time period (<.05. At the first culture, the number of CFU in the CHX + H2O2 group was lower than other two groups. At the other experimental periods, the CHX group showed the most effective antibacterial action (<.05. Hydrogen peroxide group showed the worst result at all periods. In each group, the number of CFU increased significantly by time lapse (<.05. In conclusion, H2O2 had no additive effect on the residual antibacterial activity of CHX.

  3. Photoluminescence of MoS2 quantum dots quenched by hydrogen peroxide: A fluorescent sensor for hydrogen peroxide

    Science.gov (United States)

    Gan, Zhixing; Gui, Qingfeng; Shan, Yun; Pan, Pengfei; Zhang, Ning; Zhang, Lifa

    2016-09-01

    By cutting MoS2 microcrystals to quantum dots (QDs) of sizes below 10 nm, the photoluminescence (PL) at ca. 450 nm can be detected easily due to the quantum confinement effects across the 2D planes. The PL is stable under continuous irradiation of UV light but gradually quenches when treated with an increasing concentration of hydrogen peroxide. Time-resolved PL and Raman spectra imply that H2O2 causes the partial oxidation of MoS2 QDs. First-principles calculations reveal that the MoS2 QDs with oxygen impurity are of indirect bandgap structures showing no notable PL. And absorption spectra verify that the PL of MoS2 QDs quenched by H2O2 is attributed to the oxidation. The integrated PL intensity and H2O2 concentration show an exponential relationship in the range of 2-20 μM, suggesting that MoS2 QDs are potential fluorescent probes for hydrogen peroxide sensing in a physiological environment.

  4. Contact Lens Solutions With Hydrogen Peroxide: To Avoid Injury, Follow All Instructions

    Science.gov (United States)

    ... should never put hydrogen peroxide directly into your eyes or on your contact lenses,” Lepri says. That’s because this kind of solution ... for Solutions With Hydrogen Peroxide Talk to your eye-care provider ... for your contact lenses. Never change your lens-care system before consulting ...

  5. [Intensity of lipid peroxidation in the kidneys in nephrotoxic acute renal failure (experimental study)].

    Science.gov (United States)

    Makarenko, V S; Zhiznevskaia, N G; Koltygina, T I; Gapanovich, V M; Makarenko, E V

    2000-01-01

    Mercury chloride was injected cubcutaneously in rats to induce nephrotoxic acute renal failure (ARF). Renal dysfunction in ARF occurs under intensification of lipid peroxidation in the kidneys. Pretreatment with antioxidant ionol diminishes lipid peroxidation intensity in the kidneys in ARF and restricts the severity of renal dysfunction.

  6. Role of hydrogen peroxide and hydroxyl radical in pyrite oxidation by molecular oxygen

    Science.gov (United States)

    Schoonen, Martin A. A.; Harrington, Andrea D.; Laffers, Richard; Strongin, Daniel R.

    2010-09-01

    Hydrogen peroxide and hydroxyl radical are readily formed during the oxidation of pyrite with molecular oxygen over a wide range of pH conditions. However, pretreatment of the pyrite surface influences how much of the intermediates are formed and their fate. Acid-washed pyrite produces significant amounts of hydrogen peroxide and hydroxyl radical when suspended in air-saturated water. However, the hydrogen peroxide concentration shows an exponential decrease with time. Suspensions made with partially oxidized pyrite yield significantly lower amounts of hydrogen peroxide product. The presence of Fe(III)-oxide or Fe(III)-hydroxide patches facilitates the conversion of hydrogen peroxide to oxygen and water. Hence, the degree to which a pyrite surface is covered with patches of Fe(III)-oxide or Fe(III)-hydroxide patches is an important control on the concentration of hydrogen peroxide in solution. Hydrogen peroxide appears to be an important intermediate in the four-electron transfer from pyrite to molecular oxygen. Addition of catalase, an enzyme that decomposes hydrogen peroxide to water and molecular oxygen, to a pyrite suspension reduces the oxidation rate by 40%. By contrast, hydroxyl radical does not appear to play a significant role in the oxidation mechanism. It is estimated on the basis of a molecular oxygen and sulfate mass balance that 5-6% of the molecular oxygen is consumed without forming sulfate.

  7. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents

    Directory of Open Access Journals (Sweden)

    Mohammad E. Rokaya

    2015-01-01

    Full Text Available Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n=27 according to the bleaching materials used. Each main group was divided into three subgroups (n=9 according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide, group 2 (35% carbamide peroxide, group 3 (sodium perborate-30% hydrogen peroxide mixture, and group 4 (sodium perborate-water mixture. Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey’s test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide.

  8. Effectiveness of improved hydrogen peroxide in decontaminating privacy curtains contaminated with multidrug-resistant pathogens.

    Science.gov (United States)

    Rutala, William A; Gergen, Maria F; Sickbert-Bennett, Emily E; Williams, David A; Weber, David J

    2014-04-01

    We tested the ability of an improved hydrogen peroxide solution to decontaminate privacy curtains in inpatient and outpatient areas. The microbial contamination of the curtains was assessed before and after the curtains were sprayed with improved hydrogen peroxide. The disinfectant reduced the microbial load on the privacy curtains by 96.8% in 37 patient rooms.

  9. Oxidation resistant peroxide cross-linked UHMWPE produced by blending and surface diffusion

    Science.gov (United States)

    Gul, Rizwan M.; Oral, Ebru; Muratoglu, Orhun K.

    2014-06-01

    Ultra-high molecular weight polyethylene (UHMWPE) has been widely used as acetabular cup in total hip replacement (THR) and tibial component in total knee replacement (TKR). Crosslinking of UHMWPE has been successful used to improve its wear performance leading to longer life of orthopedic implants. Crosslinking can be performed by radiation or organic peroxides. Peroxide crosslinking is a convenient process as it does not require specialized equipment and the level of crosslinking can be manipulated by changing the amount of peroxide added. However, there is concern about the long-term stability of these materials due to possible presence of by-products. Vitamin E has been successfully used to promote long-term oxidative stability of UHMWPE. In this study, UHMWPE has been crosslinked using organic peroxide in the presence of Vitamin E to produce an oxidation resistant peroxide crosslinked material. Crosslinking was performed both in bulk by mixing peroxide and resin, and only on the surface using diffusion of peroxides.The results show that UHMWPE can be crosslinked using organic peroxides in the presence of vitamin E by both methods. However, the level of crosslinking decreases with the increase in vitamin E content. The wear resistance increases with the increase in crosslink density, and oxidation resistance significantly increases due to the presence of vitamin E.

  10. N-acetylcysteine and hemodialysis treatment of a severe case of methyl ethyl ketone peroxide intoxication

    NARCIS (Netherlands)

    van Enckevort, C C G; Touw, D J; Vleming, L-J

    2008-01-01

    The plastic hardener methyl ethyl ketone peroxide (MEKP) is an unstable peroxide that releases free oxygen radicals. Ingestion of this compound induces widespread liver necrosis that is often fatal, extensive ulceration with subsequent scarring, and stenosis of the proximal digestive tract in surviv

  11. Platelet activation and lipid peroxidation in patients with acute ischemic stroke

    NARCIS (Netherlands)

    F. van Kooten (Fop); G. Ciabattoni; C. Patrono; D.W.J. Dippel (Diederik); P.J. Koudstaal (Peter Jan)

    1997-01-01

    textabstractBACKGROUND AND PURPOSE: Both platelet activation and lipid peroxidation are potential sources of vasoactive eicosanoids that can be produced via the cyclooxygenase pathway, ie, thromboxane (TX) A2, or by free radical-catalyzed peroxidation of arachidonic acid, ie, isoprostanes. We invest

  12. Novel co-agents for improved properties in peroxide cure of saturated elastomers

    NARCIS (Netherlands)

    Alvarez Grima, Maria Montserrat

    2007-01-01

    Peroxide vulcanisation is a widely used cure system for elastomers and offers many possibilities for use, mainly because of the availability of co-agents and scorch retarders. The range of applications of peroxide cure could significantly be widened, if certain mechanical properties could be improve

  13. Influence of cysteine and methionine availability on protein peroxide scavenging activity and phenolic stability in emulsions.

    Science.gov (United States)

    Zhou, Lisa; Elias, Ryan J

    2014-03-01

    Plant phenolics are secondary metabolites that have been shown to confer beneficial health effects in humans. However, many of these compounds undergo metal-catalysed oxidation reactions, leading to the generation of hydrogen peroxide (H2O2) and other reactive oxygen species that may negatively impact product stability. In proteins, methionine (Met) and cysteine (Cys) are capable of reacting directly with peroxides. Thus, the dairy proteins, casein (CAS) and β-lactoglobulin (BLG), were examined for their ability to scavenge H2O2 (400μM) and influence (-)-epigallocatechin-3-gallate (EGCG) oxidation (400μM) in Tween- or sodium dodecyl sulphate (SDS)-stabilised hexadecane emulsions. To examine the effect that the accessibility of these amino acids have on their peroxide scavenging activities, proteins were pre-treated with tert-butyl hydroperoxide (TBHP), a bulky peroxide, to oxidise only solvent accessible Met residues or H2O2, the smallest peroxide, to oxidise buried Met residues. In CAS treatments, higher Met content yielded greater peroxide scavenging activity and EGCG stability. CAS treatments also showed significantly higher peroxide scavenging activity compared to the corresponding BLG treatment. However, BLG peroxide scavenging activity was greatly enhanced in SDS-stabilised emulsions due to protein denaturation and subsequent exposure of previously buried Cys residues.

  14. Overoxidation of chloroplast 2-Cys peroxiredoxins: balancing toxic and signaling activities of hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Leonor ePuerto-Galán

    2013-08-01

    Full Text Available Photosynthesis, the primary source of biomass and oxygen into the biosphere, involves the transport of electrons in the presence of oxygen and, therefore, chloroplasts constitute an important source of reactive oxygen species (ROS, including hydrogen peroxide. If accumulated at high level, hydrogen peroxide may exert a toxic effect; however, it is as well an important second messenger. In order to balance the toxic and signaling activities of hydrogen peroxide its level has to be tightly controlled. To this end, chloroplasts are equipped with different antioxidant systems such as 2-Cys peroxiredoxins (2-Cys Prxs, thiol-based peroxidases able to reduce hydrogen- and organic peroxides. At high peroxide concentrations the peroxidase function of 2-Cys Prxs may become inactivated through a process of overoxidation. This inactivation has been proposed to explain the signaling function of hydrogen peroxide in eukaryotes, whereas in prokaryotes, the 2-Cys Prxs of which were considered to be insensitive to overoxidation, the signaling activity of hydrogen peroxide is less relevant. Here we discuss the current knowledge about the mechanisms controlling 2-Cys Prx overoxidation in chloroplasts, organelles with an important signaling function in plants. Given the prokaryotic origin of chloroplasts, we discuss the occurrence of 2-Cys Prx overoxidation in cyanobacteria with the aim of identifying similarities between chloroplasts and their ancestors regarding their response to hydrogen peroxide.

  15. Lipid Peroxides and α-Tocopherol in Rat Streptozotocin-Induced Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Higuchi,Yoshimi

    1982-06-01

    Full Text Available Measurement of lipid peroxides and alpha-tocopherol was undertaken in rats with streptozotocin-induced diabetes. In sera and livers in diabetic rats, the lipid peroxides increased but alpha-tocopherol decreased. To study the effect of vitamin E deficiency in the diabetic state, diabetes was induced in rats maintained on a vitamin E deficient diet. Serum lipid peroxides increased greatly but alpha-tocopherol decreased. Lipid peroxides and alpha-tocopherol increased in the liver of vitamin E deficient states. In the liver, vitamin E deficient diabetic rats had lower lipid peroxides levels but higher alpha-tocopherol levels than vitamin E deficient non-diabetic rats. On the basis of the present experiments, it was considered that the decrease of alpha-tocopherol might be due to consumption as an antioxidant as lipid peroxides increased in sera and livers. The decrease of lipid peroxides in the liver was thought to play an important part of the increase in serum lipid peroxides.

  16. Degradation of ethyl xanthate in flotation residues by hydrogen peroxide

    Institute of Scientific and Technical Information of China (English)

    陈兴华; 胡岳华; 彭宏; 曹学锋

    2015-01-01

    The degradation behavior of ethyl xanthate (EX) salt was the most widely used collector in sulfide mineral flotation and emission of flotation tailings with residual EX was harmful to environment. In this work, hydrogen peroxide (H2O2) was investigated by UV-visible spectroscopy (UV/Vis) at different pH values from 3 to 12. For pH value from 5 to 12, EX was oxidized into ethyl per xanthate (EPX) by H2O2. Then EPX was further oxidized into thiosulfate (TS) salt rather than ethyl thiocarbonate (ETC) and this step was the reaction-limited step. Then depending on pH values, TS was degraded into sulphate and carbonate salts (pH>7) or elemental sulfur (pH3.0 during test time.

  17. Direct synthesis of hydrogen peroxide from plasma-water interactions

    Science.gov (United States)

    Liu, Jiandi; He, Bangbang; Chen, Qiang; Li, Junshuai; Xiong, Qing; Yue, Guanghui; Zhang, Xianhui; Yang, Size; Liu, Hai; Liu, Qing Huo

    2016-12-01

    Hydrogen peroxide (H2O2) is usually considered to be an important reagent in green chemistry since water is the only by-product in H2O2 involved oxidation reactions. Early studies show that direct synthesis of H2O2 by plasma-water interactions is possible, while the factors affecting the H2O2 production in this method remain unclear. Herein, we present a study on the H2O2 synthesis by atmospheric pressure plasma-water interactions. The results indicate that the most important factors for the H2O2 production are the processes taking place at the plasma-water interface, including sputtering, electric field induced hydrated ion emission, and evaporation. The H2O2 production rate reaches ~1200 μmol/h when the liquid cathode is purified water or an aqueous solution of NaCl with an initial conductivity of 10500 μS cm‑1.

  18. Hydrogen peroxide room disinfection--ready for prime time?

    Science.gov (United States)

    Huttner, Benedikt D; Harbarth, Stephan

    2015-05-08

    Non-manual techniques for terminal disinfection of hospital rooms have gained increasing interest in recent years as means to reduce transmission of multidrug-resistant organisms (MDROs). A prospective crossover study by Blazejewski and colleagues in five ICUs of a French academic hospital with a high prevalence of MDRO carriers showed that two different hydrogen peroxide (H2O2)-based non-touch disinfection techniques reduced environmental contamination with MDROs after routine cleaning. This study provides further evidence of the 'in use' bioburden reduction offered by these techniques. Before H2O2-based non-touch disinfection can be recommended for routine clinical use outside specific outbreak situations, further studies need to show whether the environmental contamination reduction provided by these techniques is clinically relevant and results in reduced cross-infections with MDROs.

  19. A Norsesterterpene Peroxide from a Marine Sponge Hippospongia sp.

    Science.gov (United States)

    Su, Ching-chyuan; Su, Huey-jen; Liang, Kai-ju; Tsaif, Su-june; Su, Jui-hsin

    2016-04-01

    One new norsesterterpene peroxide, rhopaloic acid H (1), along with two known related metabolites 2 and 3, were isolated from a marine sponge Hippospongia sp. The structures of compounds were elucidated by means of IR, MS, and NMR techniques and comparison of the NMR data with those of known analogues. Evaluation of the cytotoxicities revealed that compound 2 exhibited significant cytotoxicity against DLD-1, Molt 4, T47D and K-562 cell lines, with IC50 values of 3.18, 0.69, 2.22 and 1.06 µg/mL, respectively. Moreover, compound 3 also showed significant K562 inhibitory activity, with IC50 value of 3.65 µg/mL.

  20. Polyester Sulphonic Acid Interstitial Nanocomposite Platform for Peroxide Biosensor

    Directory of Open Access Journals (Sweden)

    Emmanuel I. Iwuoha

    2009-12-01

    Full Text Available A novel enzyme immobilization platform was prepared on a platinum disk working electrode by polymerizing aniline inside the interstitial pores of polyester sulphonic acid sodium salt (PESA. Scanning electron microscopy study showed the formation of homogeneous sulphonated polyaniline (PANI nanotubes (~90 nm and thermogravimetric analysis (TGA confirmed that the nanotubes were stable up to 230 °C. The PANI:PESA nanocomposite showed a quasi-reversible redox behaviour in phosphate buffer saline. Horseradish peroxidase (HRP was immobilized on to this modified electrode for hydrogen peroxide detection. The biosensor gave a sensitivity of 1.33 μA (μM-1 and a detection limit of 0.185 μM for H2O2. Stability experiments showed that the biosensor retained more than 64% of its initial sensitivity over four days of storage at 4 °C.

  1. In vitro antibacterial effect of carbamide peroxide on oral biofilm

    Directory of Open Access Journals (Sweden)

    Chao Shu Yao

    2013-06-01

    Full Text Available This study compared the effects of carbamide peroxide (CP and chlorhexidine (CHX on oral biofilm in vitro. Collagen-coated hydroxyapatite discs were inoculated with subgingival plaque. After 3 weeks, the emergent biofilms were subjected to 1-, 3-, and 10-min exposures of a 1% CHX gel, a 5% CP gel and rinse, and a 10% CP gel and rinse. Subsequently, the biofilms were stained using a two-colour fluorescent dye kit for confocal laser scanning microscopy, and the volume ratio of dead bacteria to all bacteria was analysed. Compared to a non-treated gel control, the active agents killed bacteria on all the discs, with higher concentration and longer exposure times killing more bacteria. The rinse form disrupted the biofilm quicker than the gel form. Overall, 10% CP showed more disruption of biofilm and a greater proportion of killed bacteria than 1% CHX (p<0.05.

  2. Gold-catalyzed oxidation of substituted phenols by hydrogen peroxide

    KAUST Repository

    Cheneviere, Yohan

    2010-10-20

    Gold nanoparticles deposited on inorganic supports are efficient catalysts for the oxidation of various substituted phenols (2,6-di-tert-butyl phenol and 2,3,6-trimethyl phenol) with aqueous hydrogen peroxide. By contrast to more conventional catalysts such as Ti-containing mesoporous silicas, which convert phenols to the corresponding benzoquinones, gold nanoparticles are very selective to biaryl compounds (3,3′,5,5′-tetra-tert-butyl diphenoquinone and 2,2′,3,3′,5,5′-hexamethyl-4,4′- biphenol, respectively). Products yields and selectivities depend on the solvent used, the best results being obtained in methanol with yields >98%. Au offers the possibility to completely change the selectivity in the oxidation of substituted phenols and opens interesting perspectives in the clean synthesis of biaryl compounds for pharmaceutical applications. © 2010 Elsevier B.V. All rights reserved.

  3. Lipid peroxidation and water penetration in lipid bilayers

    DEFF Research Database (Denmark)

    Conte, Elena; Megli, Francesco Maria; Khandelia, Himanshu

    2012-01-01

    changes in the acyl chain order in the sub-polar region and at the methyl-terminal induced by lipid peroxidation were detected by X-band EPR. Concomitantly, the polarity and proticity of the membrane bilayer in those regions were investigated at W band in frozen samples. Analysis of the g(xx) and A......(zz) parameters revealed that OHPLPC, but mostly HpPLPC, induced a measurable increase in polarity and H-bonding propensity in the central region of the bilayer. Molecular dynamics simulation performed on 16-DSA in the PLPC-HpPLPC bilayer revealed that water molecules are statistically favored with respect...... to the hydroperoxide groups to interact with the nitroxide at the methyl-terminal, confirming that the H-bonds experimentally observed are due to increased water penetration in the bilayer. The EPR and MD data on model membranes demonstrate that cell membrane damage by oxidative stress cause alteration of water...

  4. Synthesis and reinforcement of peroxide-cured butyl rubber thermosets

    Science.gov (United States)

    Rodrigo, Antonio Cillero

    Isobutylene-rich elastomers provide the oxidative stability and impermeability required by many industrial applications. Halogenated derivatives support a wide range of chemical modification processes that can overcome most performance limitations. This research involves the modification of brominated butyl rubber (BIIR) to introduce peroxide-curable functionality in addition to aminotrialkoxysilyl groups that improve interactions with siliceous fillers, and anthraquinone functionality that serves as a polymer-bound chromophore. The thesis also describes detailed studies of the influence of counter anions on imidazolium ionomer derivatives of brominated poly(isobutylene-co-p-methylstyrene) (BIMS). Exchanging bromide with dodecyl sulfate, styrene sulfonate and montmorillonite clay platelets provided new ionomer thermosets whose rheological, tensile and adhesive properties varied considerably from their parent material.

  5. Temperature-dependent absorption cross sections for hydrogen peroxide vapor

    Science.gov (United States)

    Nicovich, J. M.; Wine, P. H.

    1988-03-01

    Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.

  6. Chemiluminescent Nanomicelles for Imaging Hydrogen Peroxide and Self-Therapy in Photodynamic Therapy

    Directory of Open Access Journals (Sweden)

    Rui Chen

    2011-01-01

    Full Text Available Hydrogen peroxide is a signal molecule of the tumor, and its overproduction makes a higher concentration in tumor tissue compared to normal tissue. Based on the fact that peroxalates can make chemiluminescence with a high efficiency in the presence of hydrogen peroxide, we developed nanomicelles composed of peroxalate ester oligomers and fluorescent dyes, called peroxalate nanomicelles (POMs, which could image hydrogen peroxide with high sensitivity and stability. The potential application of the POMs in photodynamic therapy (PDT for cancer was also investigated. It was found that the PDT-drug-loaded POMs were sensitive to hydrogen peroxide, and the PDT drug could be stimulated by the chemiluminescence from the reaction between POMs and hydrogen peroxide, which carried on a self-therapy of the tumor without the additional laser light resource.

  7. Toxic DNA Damage by Hydrogen Peroxide through the Fenton Reaction in vivo and in vitro

    Science.gov (United States)

    Imlay, James A.; Chin, Sherman M.; Linn, Stuart

    1988-04-01

    Exposure of Escherichia coli to low concentrations of hydrogen peroxide results in DNA damage that causes mutagenesis and kills the bacteria, whereas higher concentrations of peroxide reduce the amount of such damage. Earlier studies indicated that the direct DNA oxidant is a derivative of hydrogen peroxide whose formation is dependent on cell metabolism. The generation of this oxidant depends on the availability of both reducing equivalents and an iron species, which together mediate a Fenton reaction in which ferrous iron reduces hydrogen peroxide to a reactive radical. An in vitro Fenton system was established that generates DNA strand breaks and inactivates bacteriophage and that also reproduces the suppression of DNA damage by high concentrations of peroxide. The direct DNA oxidant both in vivo and in this in vitro system exhibits reactivity unlike that of a free hydroxyl radical and may instead be a ferryl radical.

  8. Peroxide induced ultra-weak chemiluminescence and its application in analytical chemistry.

    Science.gov (United States)

    Lin, Zhen; Chen, Hui; Lin, Jin-Ming

    2013-09-21

    Chemiluminescence (CL), as a sensitive, rapid, and facile analytical method, has been widely applied in environmental monitoring, clinical diagnosis and food safety. Recently, the main challenge and research interest in the CL study have been focused on exploring new CL systems and obtaining new insight into the interaction between CL reagents. The peroxide induced ultra-weak CL reactions are some new arising systems that have received great attention and have been successfully applied in many fields. The peroxide includes hydrogen peroxide, peroxynitrite, peroxymonocarbonate, peroxomonosulphate and so on. This review paper covers the mechanism of the peroxide induced ultra-weak CL and the analytical applications of the CL have also been summarized. The future prospects for the peroxide induced ultra-weak CL are discussed.

  9. THE EFFECT OF TRANSITION METAL IONS-MANGANESE ON HYDROGEN PEROXIDE BLEACHING

    Institute of Scientific and Technical Information of China (English)

    ShuhuiYang; YumengZhao; BaokuWen; YonghaoNi

    2004-01-01

    In this investigation, the catalytic activities of Mn(II),Mn(III) and Mn(IV) towards decomposing hydrogenperoxide were compared. Among Mn (II), Mn (III)and Mn (IV), Mn (II) is not catalytically active indecomposing hydrogen peroxide. However, both Mn(113) and Mn (IV) are, and Mn (III) has a strongereffect than Mn(IV).In addition, we also studied the practical methods todecrease the Mn-induced decomposition of hydrogenperoxide. The results showed that sodium silicate andmagnesium sulfite in combination can effectivelydecrease the decomposition of hydrogen peroxide.The optimum dosage of sodium silicate was about0.5% (on solution). Adding chelants such as DTPAor EDTA simultaneously with stabilizers candecrease hydrogen peroxide decomposition. For Mn(IV), the EDTA is more effective than DTPA.Adding sodium thiosulfate simultaneously withmagnesium sulfate, sodium silicate and DTPA toalkaline peroxide solution can result in more residualhydrogen peroxide, and a higher pulp brightness.

  10. Hydrogen peroxide-mediated inactivation of two chloroplastic peroxidases, ascorbate peroxidase and 2-cys peroxiredoxin.

    Science.gov (United States)

    Kitajima, Sakihito

    2008-01-01

    Reactive oxygen species (ROS), such as the superoxide anion and hydrogen peroxide, are generated by the photosystems because photoexcited electrons are often generated in excess of requirements for CO2 fixation and used for reducing molecular oxygen, even under normal environmental conditions. Moreover, ROS generation is increased in chloroplasts if plants are subjected to stresses, such as drought, high salinity and chilling. Chloroplast-localized isoforms of ascorbate peroxidase and possibly peroxiredoxins assume the principal role of scavenging hydrogen peroxide. However, in vitro studies revealed that both types of peroxidases are easily damaged by hydrogen peroxide and lose their catalytic activities. This is one contributing factor for cellular damage that occurs under severe oxidative stress. In this review, I describe mechanisms of hydrogen peroxide-mediated inactivation of these two enzymes and discuss a reason why they became susceptible to damage by hydrogen peroxide.

  11. Effects of resveratrol on hydrogen peroxide-induced oxidative stress in embryonic neural stem cells

    Institute of Scientific and Technical Information of China (English)

    Sibel Konyalioglu; Guliz Armagan; Ayfer Yalcin; Cigdem Atalayin; Taner Dagci

    2013-01-01

    Resveratrol, a natural phenolic compound, has been shown to prevent cardiovascular diseases and cancer and exhibit neuroprotective effects. In this study, we examined the neuroprotective and antioxidant effects of resveratrol against hydrogen peroxide in embryonic neural stem cells. Hydrogen peroxide treatment alone increased catalase and glutathione peroxidase activities but did not change superoxide dismutase levels compared with hydrogen peroxide + resveratrol treatment. Nitric oxide synthase activity and concomitant nitric oxide levels increased in response to hydrogen peroxide treatment. Conversely, resveratrol treatment decreased nitric oxide synthase activity and nitric oxide levels. Resveratrol also attenuated hydrogen peroxide-induced nuclear or mitochondrial DNA damage. We propose that resveratrol may be a promising agent for protecting embryonic neural stem cells because of its potential to decrease oxidative stress by inducing higher activity of antioxidant enzymes, decreasing nitric oxide production and nitric oxide synthase activity, and alleviating both nuclear and mitochondrial DNA damage.

  12. Organic peroxide production in the Cl2-ethane-air photoreaction system

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    HPLC along with FT-IR technique was used to study the formationof organic peroxides in the Cl2-ethane-air photoreaction system. Ethyl hydroperoxide (CH3CH2OOH, EHP) and peroxyacetic acid ( CH3C(O)OOH, PAA) were conformed to be the peroxide product in the reaction system. In addition, methyl hydroperoxide (CH3OOH, MHP), hydroxymethyl hydroperoxide (HOCH2OOH, HMHP) and two unidentified organic peroxides were detected for the first time. EHP and MHP were the dominant peroxide products. The identification of HMHP showed that Criegee biradical CH2OO may be formed as an intermediate in the oxidation of ethane. Simulation results showed that photo-oxidation of ethane may make substantial contribution to source of organic peroxides in the atmos-phere.

  13. An ICT-based approach to ratiometric fluorescence imaging of hydrogen peroxide produced in living cells.

    Science.gov (United States)

    Srikun, Duangkhae; Miller, Evan W; Domaille, Dylan W; Chang, Christopher J

    2008-04-09

    We present the synthesis, properties, and biological applications of Peroxy Lucifer 1 (PL1), a new fluorescent probe for imaging hydrogen peroxide produced in living cells by a ratiometric response. PL1 utilizes a chemoselective boronate-based switch to detect hydrogen peroxide by modulation of internal charge transfer (ICT) within a 1,8-naphthalimide dye. PL1 features high selectivity for hydrogen peroxide over similar reactive oxygen species, including superoxide, and nitric oxide, and a 65 nm shift in emission from blue-colored fluorescence to green-colored fluorescence upon reaction with peroxide. Two-photon confocal microscopy experiments in live macrophages show that PL1 can ratiometrically visualize localized hydrogen peroxide bursts generated in living cells at immune response levels.

  14. Natural manganese deposits as catalyst for decomposing hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    A. H. Knol

    2015-01-01

    Full Text Available Drinking water companies more and more implement Advanced Oxidation Processes (AOP in their treatment schemes to increase the barrier against organic micropollutants (OMPs. It is necessary to decompose the excessive hydrogen peroxide after applying AOP to avoid negative effects in the following, often biological, treatment steps. A drinking water company in the western part of the Netherlands investigated decomposition of about 5.75 mg L−1 hydrogen peroxide in pre-treated Meuse river water with different catalysts on pilot scale. In down flow operation, the necessary reactor Empty Bed Contact Time (EBCT with the commonly used Granulated Activated Carbon (GAC and waste ground water filter gravel (MCFgw were the same with 149 s, corresponding with a conversion rate constant r of 0.021 s−1. The EBCT of the fine coating of ground water filter gravel (MC was significantly shorter with a little more than 10 s (r = 0.30 s−1. In up flow operation, with a flow rate of 20 m h−1, the EBCT of coating MC increased till about 100 s (r = 0.031 s−1, from which can be concluded, that the performance of this waste material is better compared with GAC, in both up and down flow operation. The necessary EBCT at average filtration rate of full scale dual layer filter material (MCFsw amounted to 209 s (r = 0.015 s−1. Regarding the average residence time in the full scale filters of 700 s, applying AOP in front of the filters could be an interesting alternative which makes a separate decomposition installation superfluous, on the condition that the primary functions of the filters are not affected.

  15. Targeting lipid peroxidation and mitochondrial imbalance in Friedreich's ataxia.

    Science.gov (United States)

    Abeti, Rosella; Uzun, Ebru; Renganathan, Indhushri; Honda, Tadashi; Pook, Mark A; Giunti, Paola

    2015-09-01

    Friedreich's ataxia (FRDA) is an autosomal recessive disorder, caused by reduced levels of the protein frataxin. This protein is located in the mitochondria, where it functions in the biogenesis of iron-sulphur clusters (ISCs), which are important for the function of the mitochondrial respiratory chain complexes. Moreover, disruption in iron biogenesis may lead to oxidative stress. Oxidative stress can be the cause and/or the consequence of mitochondrial energy imbalance, leading to cell death. Fibroblasts from two FRDA mouse models, YG8R and KIKO, were used to analyse two different categories of protective compounds: deuterised poly-unsaturated fatty acids (dPUFAs) and Nrf2-inducers. The former have been shown to protect the cell from damage induced by lipid peroxidation and the latter trigger the well-known Nrf2 antioxidant pathway. Our results show that the sensitivity to oxidative stress of YG8R and KIKO mouse fibroblasts, resulting in cell death and lipid peroxidation, can be prevented by d4-PUFA and Nrf2-inducers (SFN and TBE-31). The mitochondrial membrane potential (ΔΨm) of YG8R and KIKO fibroblasts revealed a difference in their mitochondrial pathophysiology, which may be due to the different genetic basis of the two models. This suggests that variable levels of reduced frataxin may act differently on mitochondrial pathophysiology and that these two cell models could be useful in recapitulating the observed differences in the FRDA phenotype. This may reflect a different modulatory effect towards cell death that will need to be investigated further.

  16. Lipid peroxidation following superior mesenteric artery occlusion in rat intestine

    Directory of Open Access Journals (Sweden)

    P. Pasbakhsh

    2006-07-01

    Full Text Available Background: The aim of this study was to determine the level of lipid peroxidation and tissue protein after superior mesenteric artery occlusion tissue damage. The effect of melatonin as anti oxidant and free radical scavenger in prevention of tissue damage, were also evaluated. Methods: Thity six young male Wisatr-Albino rats (weight: 80-120 gr, were divided equally in 6 group with different concentrations of melatonin (10,20,30 mg/kg treatment. Group 1was control, group 2 the sham that surgical process was applied until superior mesenteric artery dissection and received vehicle solution only in equally volume by intra muscular route. Group 3 was ischemia- reperfusion (I/R, group 4 was I/R plus melatonin 10 mg/kg, group 5 I/R plus melatonin 20 mg/kg and finally group 6 I/R plus melatonin 30 mg/kg. After laparatomy, a microvascular atraumatic clip was placed across the superior mesenteric artery under general anaesthesia and itbremoved after ischemia for 30 minutes. The first dose of melatonin was applied just beforereperfusion, second dose, after reperfusion and third dose on the second day .On third day rats were killed and their bowels were removed. The level of tissue melandialdehyde (MDA as index of lipid peroxidation and tissue protein was determined. Results: The level of tissue MDA were significantly lower in group 4, 5, 6 than group 3 (p0, 05. Conclusion: These results suggest that melatonin 10 mg/kg has antioxidant effect in prevention of inducing tissue damage during SMA occlusion in rat intestine.

  17. Development of hydrogen peroxide technique for bioburden reduction

    Science.gov (United States)

    Rohatgi, N.; Schwartz, L.; Stabekis, P.; Barengoltz, J.

    In order to meet the National Aeronautics and Space Administration (NASA) Planetary Protection microbial reduction requirements for Mars in-situ life detection and sample return missions, entire planetary spacecraft (including planetary entry probes and planetary landing capsules) may have to be exposed to a qualified sterilization process. Presently, dry heat is the only NASA approved sterilization technique available for spacecraft application. However, with the increasing use of various man-made materials, highly sophisticated electronic circuit boards, and sensors in a modern spacecraft, compatibility issues may render this process unacceptable to design engineers and thus impractical to achieve terminal sterilization of the entire spacecraft. An alternative vapor phase hydrogen peroxide sterilization process, which is currently used in various industries, has been selected for further development. Strategic Technology Enterprises, Incorporated (STE), a subsidiary of STERIS Corporation, under a contract from the Jet Propulsion Laboratory (JPL) is developing systems and methodologies to decontaminate spacecraft using vaporized hydrogen peroxide (VHP) technology. The VHP technology provides an effective, rapid and low temperature means for inactivation of spores, mycobacteria, fungi, viruses and other microorganisms. The VHP application is a dry process affording excellent material compatibility with many of the components found in spacecraft such as polymers, paints and electronic systems. Furthermore, the VHP process has innocuous residuals as it decomposes to water vapor and oxygen. This paper will discuss the approach that is being used to develop this technique and will present lethality data that have been collected to establish deep vacuum VHP sterilization cycles. In addition, the application of this technique to meet planetary protection requirements will be addressed.

  18. Effects of 15% carbamide peroxide and 40% hydrogen peroxide on the microhardness and color change of composite resins.

    Directory of Open Access Journals (Sweden)

    Sedighe Sadat Hashemi Kamangar

    2014-04-01

    Full Text Available The aim of this study was to determine the effects of 40% hydrogen peroxide and 15% carbamide peroxide on microhardness and color change of a silorane-based composite resin in comparison with two methacrylate-based composites.Fifty-four disc-shaped specimens (A3 shade were fabricated of Filtek P90 (P90, Filtek Z350XT Enamel (Z350 and Filtek Z250 (Z250 (3MESPE (n=18. The samples of each composite were randomly divided into three subgroups of 6. The control subgroups were immersed in distilled water; the test groups were exposed to Opalescence Boost (OB once; and Opalescence PF (OP (Ultradent for two weeks. Vickers microhardness testing and a spectrophotometric analysis of the color of samples were performed before and after each intervention.The baseline microhardness of P90 was significantly lower than that of the other two composites (P=0.001, but no difference was found between Z250 and Z350 in this respect (P=0.293. Bleaching treatments significantly decreased the microhardness of Z250 and Z350 (P 0.05. No significant difference was detected between the two types of bleaching (P>0.05. After bleaching with OB, ΔE value was measured to be 3.12(1.97, 3.31(1.84 and 3.7(2.11 for P90, Z250 and Z350, respectively. These values were 5.98(2.42, 4.66(2.85 and 4.90(2.78 after bleaching with OP with no significant difference.Bleaching decreased the microhardness of methacrylate-based but not silorane-based composites. Although no significant differences were found in ΔE of composites, ΔE of all groups did not remain in the clinically acceptable range after bleaching except for P90 after bleaching with 40% H2O2 (ΔE < 3.3.

  19. Ionizing radiation and lipid peroxidation in human body; Radiazioni ionizzanti e perossidazione lipidica nell`organismo umano

    Energy Technology Data Exchange (ETDEWEB)

    Giubileo, Gianfranco [ENEA, Centro Ricerche Frascati, Roma (Italy)

    1997-07-01

    Lipids are organic compounds constituting the living cells. Lipid molecules can be disassembled through peroxidative pathways and hydrocarbons can be bred as end-product of lipid peroxidation in vivo. Lipid peroxidation can be started by an indirect effect of ionizing radiation. So a radioinduced cellular damage in human body can be detected by monitoring the production of specific hydrocarbons.

  20. Lipid Peroxidation: Production, Metabolism, and Signaling Mechanisms of Malondialdehyde and 4-Hydroxy-2-Nonenal

    Directory of Open Access Journals (Sweden)

    Antonio Ayala

    2014-01-01

    Full Text Available Lipid peroxidation can be described generally as a process under which oxidants such as free radicals attack lipids containing carbon-carbon double bond(s, especially polyunsaturated fatty acids (PUFAs. Over the last four decades, an extensive body of literature regarding lipid peroxidation has shown its important role in cell biology and human health. Since the early 1970s, the total published research articles on the topic of lipid peroxidation was 98 (1970–1974 and has been increasing at almost 135-fold, by up to 13165 in last 4 years (2010–2013. New discoveries about the involvement in cellular physiology and pathology, as well as the control of lipid peroxidation, continue to emerge every day. Given the enormity of this field, this review focuses on biochemical concepts of lipid peroxidation, production, metabolism, and signaling mechanisms of two main omega-6 fatty acids lipid peroxidation products: malondialdehyde (MDA and, in particular, 4-hydroxy-2-nonenal (4-HNE, summarizing not only its physiological and protective function as signaling molecule stimulating gene expression and cell survival, but also its cytotoxic role inhibiting gene expression and promoting cell death. Finally, overviews of in vivo mammalian model systems used to study the lipid peroxidation process, and common pathological processes linked to MDA and 4-HNE are shown.

  1. Leaching of a Cu-Co ore from Congo using sulphuric acidhydrogen peroxide leachants

    Directory of Open Access Journals (Sweden)

    Seo S.Y.

    2013-01-01

    Full Text Available A Cu-Co ore from Katinga Province, the Republic of Congo containing 1.5% Co and 1.6% Cu was tested to determine the leachability of Cu and Co using sulphuric acid and hydrogen peroxide mixtures at different conditions. Without hydrogen peroxide, the maximum extraction of copper and cobalt were found to be ~80% and ~15%, respectively when the acid concentration was varied between 0.36 - 1.1M. When hydrogen peroxide was added (0.008-0.042M, Cu recovery was enhanced to ~90%. Recoveries of ~90% of Co could be achieved at 20ºC, using leachants consisting of 0.36M sulphuric acid and 0.025M hydrogen peroxide after 3 hours. The reaction time to reach 90% Co extraction was reduced to less than 2 hours at 30ºC. Stabcal modelling of the Eh-pH diagrams shows the importance of hydrogen peroxide as a reductant. The decrease of solution potential (300-350 mV by adding hydrogen peroxide was confirmed by Eh measurements during the tests. The leaching follows the shrinking core model kinetics, where the rate constant is linearly dependent on hydrogen peroxide concentration in the range 0-0.025M and proportional to (1/r2 where r is the average radius of the mineral particles. The activation energy for the leaching process is 72.3 kJ/mol.

  2. Repetitive Peroxide Exposure Reveals Pleiotropic Mitogen-Activated Protein Kinase Signaling Mechanisms

    Directory of Open Access Journals (Sweden)

    Wayne Chadwick

    2011-01-01

    Full Text Available Oxidative stressors such as hydrogen peroxide control the activation of many interconnected signaling systems and are implicated in neurodegenerative disease etiology. Application of hydrogen peroxide to PC12 cells activated multiple tyrosine kinases (c-Src, epidermal growth factor receptor (EGFR, and Pyk2 and the serine-threonine kinase ERK1/2. Peroxide-induced ERK1/2 activation was sensitive to intracellular calcium chelation and EGFR and c-Src kinase inhibition. Acute application and removal of peroxide allowed ERK1/2 activity levels to rapidly subside to basal serum-deprived levels. Using this protocol, we demonstrated that ERK1/2 activation tachyphylaxis developed upon repeated peroxide exposures. This tachyphylaxis was independent of c-Src/Pyk2 tyrosine phosphorylation but was associated with a progressive reduction of peroxide-induced EGFR tyrosine phosphorylation, EGFR interaction with growth factor receptor binding protein 2, and a redistribution of EGFR from the plasma membrane to the cytoplasm. Our data indicates that components of peroxide-induced ERK1/2 cascades are differentially affected by repeated exposures, indicating that oxidative signaling may be contextually variable.

  3. MODIFIED OPAL:A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

    Institute of Scientific and Technical Information of China (English)

    Xueren Qian; Xianhui An; Wenbo Liu; Gang Yu; Zhanqian Song

    2004-01-01

    The possibility of modified opal as the stabilizer of hydrogen peroxide bleaching was investigated. The results showed that the modified opal in place of sodium silicate as the stabilizer of hydrogen peroxide bleaching is feasible. At the same dosage, above 3% ISO can be increased for both wheat straw pulp and deinked pulp. The stabilizing ability of the modified opal to hydrogen peroxide bleaching of pulp is improved markedly. It is favorable for bleaching to increase temperature and time within a permissive extent. The suitable process conditions are 10% of pulp consistency, 3% of hydrogen peroxide, 1.5% of sodium hydroxide, 3% of the modified opal, 70℃ and 60 min when the modified opal is used as the stabilizer of hydrogen peroxide bleaching. At these conditions, the brightness gain can reach about 16% ISO for wheat straw pulp. In addition, it is favorable for bleaching to add a little magnesium sulfate when the modified opal is used as the stabilizer of hydrogen peroxide bleaching, the brightness of pulp can increase I%ISO if0.05% of magnesium sulfate is added. The cost analysis indicated that the modified opal is superior to sodium silicate as the stabilizer of hydrogen peroxide bleaching in economical aspect and has further the potential of market development.

  4. Arsenic increased lipid peroxidation in rat tissues by a mechanism independent of glutathione levels.

    Science.gov (United States)

    Ramos, O; Carrizales, L; Yáñez, L; Mejía, J; Batres, L; Ortíz, D; Díaz-Barriga, F

    1995-01-01

    The role of lipid peroxidation in the mechanism of arsenic toxicity was investigated in female rats pretreated with N-acetylcysteine (NAC, a glutathione [GSH] inducer) or with buthionine sulfoximine (BSO, a GSH depletor). Rats were challenged with sodium arsenite, and sacrificed 1 hr after this treatment. Results showed that arsenic decreased GSH levels and increased lipid peroxidation in liver, kidney, and heart, with a larger effect at 18.2 mg/kg than at 14.8 mg/kg for lipid peroxidation induction. In the liver of rats treated with arsenic, pretreatment with NAC increased the levels of GSH and decreased lipid peroxidation. In kidney and heart, NAC pretreatment protected the tissues against arsenic-induced depletion of GSH levels, but the same degree of protection was not found for lipid peroxidation induction. In its turn, BSO had an additive effect with arsenic in lowering the levels of GSH in the liver and kidney, but an inverse correlation between GSH levels and lipid peroxidation was found only in liver. Arsenic content in tissues of rats pretreated with NAC was lower than in rats treated only with arsenic. In rats with depleted levels of GSH (BSO-pretreated rats), a shift in arsenic tissue distribution was found, with higher levels in skin and lower levels in kidney. A clear tendency for a positive correlation between arsenic concentration and lipid peroxidation levels was found in liver, kidney, and heart. PMID:7621808

  5. Characterization of an organic phase peroxide biosensor based on horseradish peroxidase immobilized in Eastman AQ.

    Science.gov (United States)

    Konash, Anastassija; Magner, Edmond

    2006-07-15

    Due to their frequent occurrence in food, cosmetics and pharmaceutical products, and their poor solubility in water, the detection of peroxides in organic solvents has aroused significant interest. For diagnostics or on-site testing, a fast and specific experimental approach is required. Although aqueous peroxide biosensors are well known, they are usually not suitable for nonaqueous applications due to their instability. Here we describe an organic phase biosensor for hydrogen peroxide based on horseradish peroxidase immobilized in an Eastman AQ 55 polymer matrix. Rotating disc amperometry was used to examine the effect of the solvent properties, the amount and pH of added buffer, the concentration of peroxide and ferrocene dimethanol, and the amount of Eastman AQ 55 and of enzyme on the response of the biosensor to hydrogen peroxide. The response of the biosensor was limited by diffusion. Linear responses (with detection limits to hydrogen peroxide given in parentheses) were obtained in methanol (1.2 microM), ethanol (0.6 microM), 1-propanol (2.8 microM), acetone (1.4 microM), acetonitrile (2.6 microM), and ethylene glycol (13.6 microM). The rate of diffusion of ferrocene dimethanol was more constrained than the rate of diffusion of hydrogen peroxide, resulting in a comparatively narrow linear range. The main advantages of the sensor are its ease of use and a high degree of reproducibility, together with good operational and storage stability.

  6. THE EFFECT OF TRANSITION METAL IONS-MANGANESE ON HYDROGEN PEROXIDE BLEACHING

    Institute of Scientific and Technical Information of China (English)

    Shuhui Yang; Yumeng Zhao; Baoku Wen; Yonghao Ni

    2004-01-01

    In this investigation, the catalytic activities of Mn(Ⅱ),Mn(Ⅲ) and Mn(Ⅳ) towards decomposing hydrogen peroxide were compared. Among Mn (Ⅱ), Mn (Ⅲ)and Mn (Ⅳ), Mn (Ⅱ) is not catalytically active in decomposing hydrogen peroxide. However, both Mn (Ⅲ) and Mn (Ⅳ) are, and Mn (Ⅲ) has a stronger effect than Mn(Ⅳ).In addition, we also studied the practical methods to decrease the Mn-induced decomposition of hydrogen peroxide. The results showed that sodium silicate and magnesium sulfite in combination can effectively decrease the decomposition of hydrogen peroxide.The optimum dosage of sodium silicate was about 0.5% (on solution). Adding chelants such as DTPA or EDTA simultaneously with stabilizers can decrease hydrogen peroxide decomposition. For Mn (Ⅳ), the EDTA is more effective than DTPA.Adding sodium thiosulfate simultaneously with magnesium sulfate, sodium silicate and DTPA to alkaline peroxide solution can result in more residual hydrogen peroxide, and a higher pulp brightness.

  7. HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

    Institute of Scientific and Technical Information of China (English)

    Yumeng Zhao; Shuhui Yang; Liang Sheng; Yonghao Ni

    2004-01-01

    Hydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed under alkaline condition, especially when transition metal ions exit. Experiments show that the valence of transition metal ion is also responsible for the decomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ and Fe3+. They are both catalytically active to hydrogen peroxide decomposition. Because Fe3+ is brown, it can affect the brightness of pulp directly, it can also combine with phenol, forming complexes which not only are stable structures and are difficult to be removed from pulp, but also significantly affect the brightness of pulp because of their color.Sodium silicate and magnesium sulfate, when used together, can greatly decrease hydrogen peroxide decomposition. The optimum dosage of sodium silicate is about 0.1% (on solution) for Fe2+ and 0.25% (on solution) for Fe3+. Adding chelants such as DTPA or EDTA with stabilizers simultaneously can obviously improve pulp brightness. For iron ions, the chelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite and cellulose can reduce Fe3+ to Fe2+ effectively, and pulp brightness is improved greatly. Adding sodium thiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxide solution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxide bleaching, the optimum pH value should be 10.5-12.

  8. Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract

    Institute of Scientific and Technical Information of China (English)

    Tebekeme Okoko; Diepreye Ere

    2012-01-01

    Objective: To investigate the in vitro antioxidant potential of Carica papaya (C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation. Methods: Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract (at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage. Results:Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities using in vitro models in a concentration dependent manner (P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid (P<0.05). The IC50 values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid (the reference antioxidant) possessed higher activity than the extract. Conclusions:The findings show that C. papaya leaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy. Thus, the leaves can be exploited for pharmaceutical and nutritional purposes.

  9. Lipid peroxidation and antioxidant status in colorectal cancer

    Institute of Scientific and Technical Information of China (English)

    Elzbieta Skrzydlewska; Stanislaw Sulkowski; Mariusz Koda; Bogdan Zalewski; Luiza Kanczuga-Koda; Mariola Sulkowska

    2005-01-01

    AIM: Reactive oxygen species (ROS) can induce carcinogenesis via DNA injury. Both enzymatic and non-enzymatic parameters participate in cell protection against harmful influence of oxidative stress. The aim of the present study was to assess the levels of final lipid peroxidation products like malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE) in primary colorectal cancer. Moreover, we analysed the activity of main antioxidative enzymes, superoxide dismutase (Cu, Zn-SOD),catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GSSRG-R) and the level of nonenzymatic antioxidants (glutathione, vitamins C and E).METHODS: Investigations were conducted in 81 primary colorectal cancers. As a control, the same amount of sample was collected from macroscopically unchanged colon regions of the most distant location to the cancer.Homogenisation of specimens provided 10% homogenates for our evaluations. Activity of antioxidant enzymes and level of glutathione were determined by spectrophotometry.HPLC revealed levels of vitamins C and E and served as a method to detect terminal products of lipid peroxidation in colorectal cancer.RESULTS: Our studies demonstrated a statistically significant increase in the level of lipid peroxidation products (MDA-Adc.muc.-2.65±0.48 nmol/g, Adc. G3-2.15±0.44 nmol/g, clinical Ⅳ stage 4.04±0.47 nmol/g, P<0.001 and 4-HNE-Adc.muc.-0.44±0.07 nmol/g, Adc. G3-0.44±0.10 nmol/g, clinical Ⅳstage 0.52±0.11 nmol/g, P<0.001) as well as increase of Cu,Zn-SOD (Adc.muc.-363±72 U/g, Adc. G3-318±48 U/g,clinical Ⅳ stage 421±58 U/g, P<0.001), GSH-Px (Adc.muc.-2143±623 U/g, Adc. G3-2005±591 U/g, clinical Ⅳ stage 2467±368 U/g, P<0.001) and GSSG-R (Adc. muc.-880±194 U/g,Adc. G3-795±228 U/g, dinical Ⅳ stage 951±243 U/g, P<0.001)in primary tumour comparison with normal colon (MDA1.39±0.15 nmol/g, HNE-0.29±0.03 nmol/g, Cu, Zn-SOD-117±25 U/g, GSH-Px-1723±189 U/g, GSSG-R-625±112 U/g)especially in mucinous and G3

  10. Hydrogen peroxide in exhaled breath condensate: A clinical study

    Directory of Open Access Journals (Sweden)

    C Nagaraja

    2012-01-01

    Full Text Available Objectives: To study the ongoing inflammatory process of lung in healthy individuals with risk factors and comparing with that of a known diseased condition. To study the inflammatory response to treatment. Background: Morbidity and mortality of respiratory diseases are raising in trend due to increased smokers, urbanization and air pollution, the diagnosis of these conditions during early stage and management can improve patient′s lifestyle and morbidity. Materials and Methods: One hundred subjects were studied from July 2010 to September 2010; the level of hydrogen peroxide concentration in exhaled breath condensate was measured using Ecocheck. Results: Of the 100 subjects studied, 23 were healthy individuals with risk factors (smoking, exposure to air pollution, and urbanization; the values of hydrogen peroxide in smokers were 200-2220 nmol/l and in non-smokers 340-760 nmol/l. In people residing in rural areas values were 20-140 nmol/l in non-smokers and 180 nmol/l in smokers. In chronic obstructive pulmonary disease cases, during acute exacerbations values were 540-3040 nmol/l and 240-480 nmol/l following treatment. In acute exacerbations of bronchial asthma, values were 400-1140 nmol/l and 100-320 nmol/l following treatment. In cases of bronchiectasis, values were 300-340 nmol/l and 200-280 nmol/l following treatment. In diagnosed pneumonia cases values were 1060-11800 nmol/l and 540-700 nmol/l following treatment. In interstitial lung diseases, values ranged from 220-720 nmol/l and 210-510 nmol/l following treatment. Conclusion: Exhaled breath condensate provides a non-invasive means of sampling the lower respiratory tract. Collection of exhaled breath condensate might be useful to detect the oxidative destruction of the lung as well as early inflammation of the airways in a healthy individual with risk factors and comparing the inflammatory response to treatment.

  11. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Chemistry; Smith, B.F. [Los Alamos National Lab., NM (United States)

    1991-11-01

    The first measurements of distribution coefficients (K{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}`s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}`s for these actinides are about a factor of 5 to 10 greater than the K{sub d}`s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}`s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand.

  12. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Chemistry); Smith, B.F. (Los Alamos National Lab., NM (United States))

    1991-11-01

    The first measurements of distribution coefficients (K{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}'s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}'s for these actinides are about a factor of 5 to 10 greater than the K{sub d}'s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}'s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand.

  13. Separation studies of yttrium(III) and lanthanide(III) ions with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and trioctylphosphine oxide using a robotic extraction system

    Energy Technology Data Exchange (ETDEWEB)

    Nekimken, H.L.; Smith, B.F.; Jarvinen, G.D.; Bartholdi, C.S. [Los Alamos National Lab., NM (United States)

    1992-07-01

    We studied the extraction of trivalent Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Er, and Lu from aqueous perchlorate solutions using a mixture of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (HBMPPT) and trioctylphosphine oxide (TOPO). The metal ion distribution coefficients (D-values) as a function of increasing lanthanide atomic number increased initially, reached a maximum value at Nd, then decreased to a nearly constant value for Gd and the later lanthanides. The D-values vary slightly across the lanthanide series, the maximum difference being a factor of 14 between La and Nd. Analysis of slopes of plots of log D versus pH, log [HBMPPT], and log [TOPO] indicated that the stoichiometries of the extraction complexes varied across the lanthanide series showing a decrease in the number of HBMPPT (and/or BMPPT) units and an increase in the number of TOPO molecules involved in the major extraction species. This extraction system can provide a good way to separate the trivalent actinides from the trivalent lanthanides. 21 refs., 2 figs., 3 tabs.

  14. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-Dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and Tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. [Lawrence Berkeley Lab., CA (United States); Smith, B.F. [Los Alamos National Lab., NM (United States)

    1992-07-01

    The first measurements of distribution coefficients (k{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}`s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}`s for these actinides are about about a factor of 10 greater than the K{sub d}`s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}`s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand. 9 refs., 2 figs., 1 tab.

  15. (2-Benzoyl-1-phenylethenolato-κ2O,O′bis[2-(1-phenyl-1H-benzimidazol-2-ylphenyl-κC1]iridium(III dichloromethane disolvate

    Directory of Open Access Journals (Sweden)

    Stanislav I. Bezzubov

    2016-12-01

    Full Text Available We present here synthesis and crystal structure of a neutral IrIII complex, [Ir(C19H13N22(C15H11O2]·2CH2Cl2 or [Ir(C^N2O^O]·2CH2Cl2, where C^N is 1,2-diphenyl-1H-benzimidazole and O^O is 2-benzoyl-1-phenylethenolate. The coordination sphere of the IrIII atom, located on a twofold rotation axis, is that of a slighlty distorted C2N2O2 octahedron, with the N atoms in a trans configuration. In the crystal, complex molecules assemble through weak C—H...π interactions in the range 2.699 (3–2.892 (3 Å. The solvent CH2Cl2 molecules reside in channels aligned along the a axis and are connected to the complex molecules by C—H...O interactions.

  16. Selective preconcentration/separation of copper(II), iron(III), and lead(II) as their N'-benzoyl-N,N-diisobutylthiourea chelates on Amberlite XAD-16 resin.

    Science.gov (United States)

    Soylak, Mustafa; Kariper, I Afsin

    2010-01-01

    A preconcentration/separation procedure for copper(II), iron(III), and lead(II) ions has been established for use prior to their flame atomic absorption spectrometric determination. The presented procedure is based on adsorption of analyte ions on Amberlite XAD-16 resin as their N'-benzoyl-N,N-diisobutylthiourea chelates. The influence of analytical parameters including pH of the solutions and type of eluent on the recoveries of Cu(II), Fe(III), and Pb(II) ions was investigated. The recoveries of the analytes were generally > 95%. No interference effects were observed from alkaline, earth alkaline, or transition metals on the recoveries of the studied metals. The LODs based on 3sigma were 1.9 microg/L for Cu, 5.9 microg/L for Fe, and 3.1 microg/L for Pb. Validation of the procedure was carried out by analyzing standard reference material 1568a (rice flour). The procedure was applied to the determination of analytes in natural water samples.

  17. [Effect of acute alcohol intoxication on lipid peroxidation in testis and adrenal glands of rats].

    Science.gov (United States)

    Khokha, A M; Kashko, M F; Antsulevich, S N; Doroshkevich, N A; Voronov, P P

    1993-01-01

    Hormones level and lipid peroxidation processes under influence of acute alcohol intoxication are tested in testes and adrenals of rats. Ethanol marker effects--the rise of corticosterone biosynthesis and depression of testosterone concentration--were reproduced in the experiment. At the moment of maximal changes in steroid levels indices characterising lipid peroxidation didn't differ from the control. At the early stage of the experiment transient shifts in malonic dialdehyde and dienic conjugates levels were noted. The data obtained does not agree with the hypothesis of acute ethanol effects in testes and adrenals being mediated through the changes of lipid peroxidation rate.

  18. Palm olein oil produces less lipid peroxidation products than soya bean oil.

    Science.gov (United States)

    Zaiton, Z; Merican, Z; Khalid, B A; Mohamed, J B; Baharom, S

    1997-06-01

    The soleus muscles of hyperthyroid rats were used to investigate the effect of palm olein oil and soya bean oil on the production of lipid peroxidation products. It was found that palm olein oil but not soya bean oil significantly decreased malonaldehyde and conjugated diene levels of the soleus muscles of hyperthyroid rats. These findings suggest that palm olein per se produces less lipid peroxidation products than soya bean oil. Such an assay method gives a composite net picture of the propensity of an oil to produce lipid peroxidation products.

  19. Considerations for Storage of High Test Hydrogen Peroxide (HTP) Utilizing Non-Metal Containers

    Science.gov (United States)

    Moore, Robin E.; Scott, Joseph P.; Wise, Harry

    2005-01-01

    When working with high concentrations of hydrogen peroxide, it is critical that the storage container be constructed of the proper materials, those which will not degrade to the extent that container breakdown or dangerous decomposition occurs. It has been suggested that the only materials that will safely contain the peroxide for a significant period of time are metals of stainless steel construction or aluminum use as High Test Hydrogen Peroxide (HTP) Containers. The stability and decomposition of HTP will be also discussed as well as various means suggested in the literature to minimize these problems. The dangers of excess oxygen generation are also touched upon.

  20. Hydrogen peroxide thermochemical oscillator as driver for primordial RNA replication.

    Science.gov (United States)

    Ball, Rowena; Brindley, John

    2014-06-06

    This paper presents and tests a previously unrecognized mechanism for driving a replicating molecular system on the prebiotic earth. It is proposed that cell-free RNA replication in the primordial soup may have been driven by self-sustained oscillatory thermochemical reactions. To test this hypothesis, a well-characterized hydrogen peroxide oscillator was chosen as the driver and complementary RNA strands with known association and melting kinetics were used as the substrate. An open flow system model for the self-consistent, coupled evolution of the temperature and concentrations in a simple autocatalytic scheme is solved numerically, and it is shown that thermochemical cycling drives replication of the RNA strands. For the (justifiably realistic) values of parameters chosen for the simulated example system, the mean amount of replicant produced at steady state is 6.56 times the input amount, given a constant supply of substrate species. The spontaneous onset of sustained thermochemical oscillations via slowly drifting parameters is demonstrated, and a scheme is given for prebiotic production of complementary RNA strands on rock surfaces.

  1. Taro Tube Flour Modification via Hydrogen Peroxide Oxidation

    Directory of Open Access Journals (Sweden)

    Catarina Sri Budiyati

    2014-10-01

    Full Text Available Colocasia esculentum (L Schott known as “Talas bogor” in Indonesian language is easily grown in every island in Indonesia. It proved to have high content of carbohydrate as it can be utilize for wheat flour replacement in addition to prior modification using hydrogen peroxide. The objective of this research was to improve the quality of taro flour by assessing the effect of several parameter such as ratio of slurry, oxidation agent concentration, oxidation time and temperature. The result shows that using ratio of slurry 20% with 2% of H2O2 concentration in temperature of oxidation process 30oC and 60 min operation time can produced good quality of modified taro tube flour in terms of swelling power and water solubility with 7.2 g/g and 6.93% respectively. This condition has chosen by taking the technical and economic feasibility as consideration. This result also can be used as proof of evidence that using H2O2 as an oxidizing agent in the process of taro tube flour modification can improve the functional properties of the flour. As the swelling power and water solubility of original taro tube flour were 3.7 g/g and 1.8% respectively.

  2. Hydrogen peroxide regulates cell adhesion through the redox sensor RPSA.

    Science.gov (United States)

    Vilas-Boas, Filipe; Bagulho, Ana; Tenente, Rita; Teixeira, Vitor H; Martins, Gabriel; da Costa, Gonçalo; Jerónimo, Ana; Cordeiro, Carlos; Machuqueiro, Miguel; Real, Carla

    2016-01-01

    To become metastatic, a tumor cell must acquire new adhesion properties that allow migration into the surrounding connective tissue, transmigration across endothelial cells to reach the blood stream and, at the site of metastasis, adhesion to endothelial cells and transmigration to colonize a new tissue. Hydrogen peroxide (H2O2) is a redox signaling molecule produced in tumor cell microenvironment with high relevance for tumor development. However, the molecular mechanisms regulated by H2O2 in tumor cells are still poorly known. The identification of H2O2-target proteins in tumor cells and the understanding of their role in tumor cell adhesion are essential for the development of novel redox-based therapies for cancer. In this paper, we identified Ribosomal Protein SA (RPSA) as a target of H2O2 and showed that RPSA in the oxidized state accumulates in clusters that contain specific adhesion molecules. Furthermore, we showed that RPSA oxidation improves cell adhesion efficiency to laminin in vitro and promotes cell extravasation in vivo. Our results unravel a new mechanism for H2O2-dependent modulation of cell adhesion properties and identify RPSA as the H2O2 sensor in this process. This work indicates that high levels of RPSA expression might confer a selective advantage to tumor cells in an oxidative environment.

  3. Etching of germanium-tin using ammonia peroxide mixture

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yuan; Ong, Bin Leong; Wang, Wei; Gong, Xiao; Liang, Gengchiau; Yeo, Yee-Chia, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Zhang, Zheng; Pan, Jisheng [Institute of Material Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03, Innovis, Singapore 138634 (Singapore); Tok, Eng-Soon [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

    2015-12-28

    The wet etching of germanium-tin (Ge{sub 1-x}Sn{sub x}) alloys (4.2% < x < 16.0%) in ammonia peroxide mixture (APM) is investigated. Empirical fitting of the data points indicates that the etch depth of Ge{sub 1-x}Sn{sub x} is proportional to the square root of the etch time t and decreases exponentially with increasing x for a given t. In addition, X-ray photoelectron spectroscopy results show that increasing t increases the intensity of the Sn oxide peak, whereas no obvious change is observed for the Ge oxide peak. This indicates that an accumulation of Sn oxide on the Ge{sub 1-x}Sn{sub x} surface decreases the amount of Ge atoms exposed to the etchant, which accounts for the decrease in etch rate with increasing etch time. Atomic force microscopy was used to examine the surface morphologies of the Ge{sub 0.918}Sn{sub 0.082} samples. Both root-mean-square roughness and undulation periods of the Ge{sub 1-x}Sn{sub x} surface were observed to increase with increasing t. This work provides further understanding of the wet etching of Ge{sub 1-x}Sn{sub x} using APM and may be used for the fabrication of Ge{sub 1-x}Sn{sub x}-based electronic and photonic devices.

  4. Specific aquaporins facilitate the diffusion of hydrogen peroxide across membranes.

    Science.gov (United States)

    Bienert, Gerd P; Møller, Anders L B; Kristiansen, Kim A; Schulz, Alexander; Møller, Ian M; Schjoerring, Jan K; Jahn, Thomas P

    2007-01-12

    The metabolism of aerobic organisms continuously produces reactive oxygen species. Although potentially toxic, these compounds also function in signaling. One important feature of signaling compounds is their ability to move between different compartments, e.g. to cross membranes. Here we present evidence that aquaporins can channel hydrogen peroxide (H2O2). Twenty-four aquaporins from plants and mammals were screened in five yeast strains differing in sensitivity toward oxidative stress. Expression of human AQP8 and plant Arabidopsis TIP1;1 and TIP1;2 in yeast decreased growth and survival in the presence of H2O2. Further evidence for aquaporin-mediated H2O2 diffusion was obtained by a fluorescence assay with intact yeast cells using an intracellular reactive oxygen species-sensitive fluorescent dye. Application of silver ions (Ag+), which block aquaporin-mediated water diffusion in a fast kinetics swelling assay, also reversed both the aquaporin-dependent growth repression and the H2O2-induced fluorescence. Our results present the first molecular genetic evidence for the diffusion of H2O2 through specific members of the aquaporin family.

  5. Oxidative stress: Lipid peroxidation products as predictors in disease progression

    Directory of Open Access Journals (Sweden)

    Suranjana Ray Halder

    2014-09-01

    Full Text Available Oxidative stress is implicated in the pathogenesis of numerous disease processes, including diabetes mellitus, atherosclerosis, ischemia reperfusion injury, rheumatoid arthritis, neurodegenerative diseases as well as in the aging process. Chemical modification of amino acids in protein during lipid peroxidation (LPO results in the formation of lipoxidation products, which may serve as indicators of oxidative stress in vivo. The various types of aldehydes such as 4-hydroxynonenal, malondialdehyde, acrolein and others produced during LPO may serve as potent oxidative stress biomarkers. Their activation in different signaling cascades lead to apoptosis, differentiation, proliferation, etc., Increased amount of these aldehydes in aging or with metabolic complications or in other diseases indicate their pathophysiological significance. Thus, LPO products or other oxidative stress biomarkers may open the way for the development of early detection, prevention, and therapeutic strategies for stress associated human diseases. Now-a-days, antioxidant supplementation has become an increasingly popular practice to restore the redox homeostatic condition of the cell. Disease specific, target directed, bioavailable antioxidants may be beneficial for sustenance of the quality-of-life in future days. [J Exp Integr Med 2014; 4(3.000: 151-164

  6. Hydrogen peroxide sensing based on carbon quantum dots

    Directory of Open Access Journals (Sweden)

    Chu Cheng-Shane

    2016-01-01

    Full Text Available In this work, carbon quantum dots (CQDs have been synthesized by one step hydrothermal method to detect hydrogen peroxide (H2O2. The optical H2O2 sensors were based on the fluorescent quenching of the carbon quantum dots. The optical H2O2 sensors demonstrate capable of detecting H2O2 over the range of 0-88.2 mM and 0-60 mM. The H2O2 sensitivities of wavelength shift to changes in the H2O2 concentration were found to be 0.18 nm/mM and 0.26 nm/mM. These results of the optical sensors showed that the method can be used in practice detection of H2O2 and could offer a new approach for developing a new optical biosensor. The CQDs exhibit good emission property and high stability, as well as excitation-independent emission behavior. Moreover, it is attractive that CQDs can be used as an effective fluorescent probe for the detection of H2O2 with linear Stern-Volmer plot and wavelength shift in an aqueous solution.

  7. Mobile gene silencing in Arabidopsis is regulated by hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Dacheng Liang

    2014-12-01

    Full Text Available In plants and nematodes, RNAi can spread from cells from which it is initiated to other cells in the organism. The underlying mechanism controlling the mobility of RNAi signals is not known, especially in the case of plants. A genetic screen designed to recover plants impaired in the movement but not the production or effectiveness of the RNAi signal identified RCI3, which encodes a hydrogen peroxide (H2O2-producing type III peroxidase, as a key regulator of silencing mobility in Arabidopsis thaliana. Silencing initiated in the roots of rci3 plants failed to spread into leaf tissue or floral tissue. Application of exogenous H2O2 reinstated the spread in rci3 plants and accelerated it in wild-type plants. The addition of catalase or MnO2, which breaks down H2O2, slowed the spread of silencing in wild-type plants. We propose that endogenous H2O2, under the control of peroxidases, regulates the spread of gene silencing by altering plasmodesmata permeability through remodelling of local cell wall structure, and may play a role in regulating systemic viral defence.

  8. Aldehydic lipid peroxidation products derived from linoleic acid.

    Science.gov (United States)

    Spiteller, P; Kern, W; Reiner, J; Spiteller, G

    2001-04-30

    Lipid peroxidation (LPO) processes observed in diseases connected with inflammation involve mainly linoleic acid. Its primary LPO products, 9-hydroperoxy-10,12-octadecadienoic acid (9-HPODE) and 13-hydroperoxy-9,11-octadecadienoic acid (13-HPODE), decompose in multistep degradation reactions. These reactions were investigated in model studies: decomposition of either 9-HPODE or 13-HPODE by Fe(2+) catalyzed air oxidation generates (with the exception of corresponding hydroxy and oxo derivatives) identical products in often nearly equal amounts, pointing to a common intermediate. Pairs of carbonyl compounds were recognized by reacting the oxidation mixtures with pentafluorobenzylhydroxylamine. Even if a pure lipid hydroperoxide is subjected to decomposition a great variety of products is generated, since primary products suffer further transformations. Therefore pure primarily decomposition products of HPODEs were exposed to stirring in air with or without addition of iron ions. Thus we observed that primary products containing the structural element R-CH=CH-CH=CH-CH=O add water and then they are cleaved by retroaldol reactions. 2,4-Decadienal is degraded in the absence of iron ions to 2-butenal, hexanal and 5-oxodecanal. Small amounts of buten-1,4-dial were also detected. Addition of m-chloroperbenzoic acid transforms 2,4-decadienal to 4-hydroxy-2-nonenal. 4,5-Epoxy-2-decenal, synthetically available by treatment of 2,4-decadienal with dimethyldioxirane, is hydrolyzed to 4,5-dihydroxy-2-decenal.

  9. Solvothermal method to prepare graphene quantum dots by hydrogen peroxide

    Science.gov (United States)

    Tian, Renbing; Zhong, Suting; Wu, Juan; Jiang, Wei; Shen, Yewen; Jiang, Wei; Wang, Tianhe

    2016-10-01

    Graphene quantum dots (GQDs) have been synthesized by different chemical methods in recent years. For conventional chemical methods, it is inevitable to introduce a large amount of impurities in the preparation process. Long time of dialysis process increases the time cost extremely. Herein, we report a one-step solvothermal method for synthesizing GQDs with the application of hydrogen peroxide in N, N-Dimethylformamide (DMF) environment, which completely avoids the use of concentrated sulphuric acid and nitric acid to treat raw material and introduces no impurity in whole preparation process simultaneously for the first time. Pure GQDs can be obtained after evaporation/redissolution and filtration process with a strong blue emission at 15% quantum yield. This solvothermal method, not requiring dialysis process and complicated equipments, exhibits simple, eco-friendly and low time-cost properties. Besides high quantum yields, the as-prepared GQDs also show good photoluminescence stability in different pH conditions. The optical properties, morphology and structure of GQDs were studied by various equipments, implying potential application in biomedical fields and electronic device.

  10. Salidroside inhibits endogenous hydrogen peroxide induced cytotoxicity of endothelial cells.

    Science.gov (United States)

    Zhao, Xingyu; Jin, Lianhai; Shen, Nan; Xu, Bin; Zhang, Wei; Zhu, Hongli; Luo, Zhengli

    2013-01-01

    Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L., shows potent antioxidant property. Herein, we investigated the protective effects of salidroside against hydrogen peroxide (H2O2)-induced oxidative damage in human endothelial cells (EVC-304). EVC-304 cells were incubated in the presence or absence of low steady states of H2O2 (3-4 µM) generated by glucose oxidase (GOX) with or without salidroside. 3(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) assays were performed, together with Hoechst 33258 staining and flow cytometric analysis using Annexin-V and propidium iodide (PI) label. The results indicated that salidroside pretreatment attenuated endogenous H2O2 induced apoptotic cell death in EVC-304 cells in a dose-dependent pattern. Furthermore, Western blot data revealed that salidroside inhibited activation of caspase-3, 9 and cleavage of poly(ADP-ribose) polymerase (PARP) induced by endogenous H2O2. It also decreased the expression of Bax and rescued the balance of pro- and anti-apoptotic proteins. All these results demonstrated that salidroside may present a potential therapy for oxidative stress in cardiovascular and cerebrovascular diseases.

  11. Electrochemical reduction of hydrogen peroxide on stainless steel

    Indian Academy of Sciences (India)

    S Patra; N Munichandraiah

    2009-09-01

    Electrochemical reduction of hydrogen peroxide is studied on a sand-blasted stainless steel (SSS) electrode in an aqueous solution of NaClO4. The cyclic voltammetric reduction of H2O2 at low concentrations is characterized by a cathodic peak at -0.40 V versus standard calomel electrode (SCE). Cyclic voltammetry is studied by varying the concentration of H2O2 in the range from 0.2 mM to 20 mM and the sweep rate in the range from 2 to 100 mV s-1. Voltammograms at concentrations of H2O2 higher than 2 mM or at high sweep rates consist of an additional current peak, which may be due to the reduction of adsorbed species formed during the reduction of H2O2. Amperometric determination of H2O2 at -0.50 V vs SCE provides the detection limit of 5 M H2O2. A plot of current density versus concentration has two segments suggesting a change in the mechanism of H2O2 reduction at concentrations of H2O2 ≥ 2 mM. From the rotating disc electrode study, diffusion co-efficient of H2O2 and rate constant for reduction of H2O2 are evaluated.

  12. Stimulated Growth of Aerobic Microbes Using Calcium Peroxide

    Institute of Scientific and Technical Information of China (English)

    LIU Shejiang; LI Mujin; JIANG Bin; LI Xingang

    2006-01-01

    With continuous and slow oxygen-release characteristic,calcium peroxide (CaO2) has been a new source of supplying oxygen for aerobic microbes in bioremediation of contaminated groundwater.Batch experiments were conducted to evaluate the oxygen-release rate of CaO2 reacting with water,the regulation of high pH,as well as the growth of mixed aerobic microbes in the medium containing CaO2.The results show that the oxygen-release process of CaO2 comprises three phases.In the first phase,dissolved oxygen levels of water increased sharply,and average oxygen-release rates increased as the adding weight of CaO2 increased.However,the rates almost ly.As the necessary components of medium,potassium dihydrogen phosphate (KH2PO4) and ammonium sulphate ((NH4)2SO4) at a certain ratio could regulate pH caused by CaO2 from 12.1 to the range of 6.5-8.5,which is helpful for microbial growth.In addition,diauxic growth curve observed in the medium containing CaO2 suggested that the growth of mixed aerobic microbes could be stimulated by the addition of CaO2.

  13. Simultaneous electroanalysis of peroxyacetic acid and hydrogen peroxide.

    Science.gov (United States)

    Awad, M I; Harnoode, C; Tokuda, K; Ohsaka, T

    2001-04-15

    The electrochemical behavior of peroxyacetic acid (PAA) in the presence of hydrogen peroxide (H2O2) has been investigated using cyclic voltammetry and hydrodynamic techniques [rotating disk electrode (RDE) voltammetry and rotating ring-disk electrode (RRDE) voltammetry]. The results have been analyzed aiming at simultaneous electroanalysis of both species. Glassy carbon and gold electrodes were used for this investigation. It was found that the reduction of PAA, as well as H2O2, is highly sensitive to the electrode material; for example, at 100 mV s-1, the reduction peak potentials of PAA were 0.2 and -1.1 V at gold and glassy carbon electrodes, respectively. The well-separated steady-state limiting currents were obtained using a gold electrode for the reduction of both PAA and H2O2 and also a well-defined one for the oxidation of H2O2. On the basis of the RDE experiments, good calibration curves were obtained for both species over a wide range of their concentrations, for PAA and H2O2 in the range of 0.36 to 110 and 0.11 to 34 mM, respectively. The simultaneous and selective electroanalysis of PAA and H2O2 in their coexistence is demonstrated for the first time.

  14. Effects of calmodulin antagonists on radiation-induced lipid peroxidation in microsomes

    Energy Technology Data Exchange (ETDEWEB)

    Varshney, R.; Kale, R.K. (Jawaharlal Nehru Univ., New Delhi (India). School of Life Sciences)

    1990-11-01

    Rat liver microsomes were irradiated with {gamma}-rays at a dose of 1.31 Gy s{sup -1}. The extent of lipid peroxidation, measured in terms of malondialdehyde (MDA) formed, increased with radiation dose. The presence of calmodulin antagonists during irradiation decreased lipid peroxidation. The order of their protective efficiency was: chlorpromazine (CPZ)>promethazine (PMZ)>trimeprazine (TMZ). Their protective effect was diminished in the presence of ferrous (Fe{sup 2+}) ions and was restored on addition of EDTA. However, calmodulin antagonists considerably inhibited radiation-induced lipid peroxidation in the presence of ferric (Fe{sup 3+}) ions. Calmodulin antagonists also decreased the cytochrome P-450 content of microsomes. These results are discussed with respect to their applicability to radiotherapy. A possible mechanism for the inhibition of radiation-induced lipid peroxidation is suggested. (author).

  15. Effect of hydrogen peroxide treatment on the properties of wool fabric

    Science.gov (United States)

    Wang, Xin; Shen, Xiaolin; Xu, Weilin

    2012-10-01

    In this study, hydrogen peroxide treatment was applied to improve the surface wettability, moisture transfer properties and other related properties of wool fabric. SEM images showed the tip of wool scale was smoothened and parts of the scale were peeled off after hydrogen peroxide treatment. The time for a water droplet to sink into the fabric could decrease to less than 1 s and the wicking properties of wool fabrics were dramatically improved after hydrogen peroxide treatment. Shrinkage and whiteness of the fabric were improved due to the modification of scale and the bleaching effect of hydrogen peroxide, respectively. The fabrics became weaker and ductile with less than 4% weight loss. This study would benefit further application of wool fiber in summer clothing in which the surface wettability and moisture transfer properties are essential and determinative.

  16. MICROWAVE-EXPEDITED OLEFIN EPOXIDATION OVER HYDROTALCITES USING HYDROGEN PEROXIDE AND ACETONITRILE

    Science.gov (United States)

    An efficient microwave-assisted expoxidation of olefins is described over hydrotalcite catalysts in the presence of hydrogen peroxide and acetonitrile. This general and selective protocol is extremely fast and is applicable to a wide variety of subtrates.

  17. Amelioration of ionizing radiation induced lipid peroxidation in mouse liver by Moringa oleifera Lam. leaf extract.

    Science.gov (United States)

    Sinha, Mahuya; Das, Dipesh Kr; Datta, Sanjukta; Ghosh, Santinath; Dey, Sanjit

    2012-03-01

    Protective effect of Moringa oleifera leaf extract (MoLE) against radiation-induced lipid peroxidation has been investigated. Swiss albino mice, selected from an inbred colony, were administered with MoLE (300 mg/kg body wt) for 15 days before exposing to a single dose of 5 Gy 60Co-gamma radiation. After treatments, animals were necropsied at different post irradiation intervals (days 1, 7 and 15) and hepatic lipid peroxidation and reduced glutathione (GSH) contents were estimated to observe the relative changes due to irradiation and its possible amelioration by MoLE. It was observed that, MoLE treatment restored GSH in liver and prevented radiation induced augmentation in hepatic lipid peroxidation. Phytochemical analysis showed that MoLE possess various phytochemicals such as ascorbic acid, phenolics (catechin, epicatechin, ferulic acid, ellagic acid, myricetin) etc., which may play the key role in prevention of hepatic lipid peroxidation by scavenging radiation induced free radicals.

  18. Influence of cosmic radiationon lymphocyte micronucleus,serum lipid peroxide and antioxidation capacity inaircrew members

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This study looks into the influence of cosmic radiation at high altitudes on human bodies. Results reveal that the cytokinesis-block micronuclei (CBMN) and conventional cultured micronuclei in peripheral blood lymphocytes, serum levels of lipid peroxide, superoxide dismutase, and the total antioxidation capacity by chemical colorimetry all increased significantly in aircrew members. There exists a linear relationship between the CBMN and the average annual effective doses of radiation received or the average annual flying hours. With both of them, a trend shows that the serum lipid peroxide levels increase as well. Either the lipid peroxide or CBMN can sensitively reflect the recent changes in flight load. These findings indicate that cosmic radiation impairs the stability of chromosomes and genome, and induces lipid oxidative damage in aircrews; Lymphocyte CBMN and serum lipid peroxide can be used as monitoring indicators in the cosmic radiation protection for aircrew members.

  19. Effect of x-ray irradiation on lipid peroxide levels in the rat submandibular gland

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, M.; Takashima, H.; Oka, T.; Ohishi, N.; Yagi, K.

    1986-07-01

    We examined the effect of local x-ray irradiation on the changes in the lipid peroxide level in submandibular gland, liver, and blood plasma. Rats five weeks of age received a single low dose of 3 Gy x-ray irradiation to their neck regions. The lipid peroxide level in the submandibular gland was significantly enhanced at seven days after irradiation, as was the level in the blood plasma at two hours, seven and 14 days after irradiation. The lipid peroxide level in the liver decreased, as compared with levels in the controls. There was a slight tendency for acinar cells of the submandibular gland to show pyknosis and anomalous nuclei within three days after irradiation. These results suggest that radiation injury results in an elevation of the lipid peroxides in the submandibular gland, and an increased level in the blood.

  20. SIMULTANEOUS REACTION AND LIQUID-LIQUID EXTRACTION IN THE HYDROGEN PEROXIDE PRODUCTION

    Institute of Scientific and Technical Information of China (English)

    ShuxiangLǖ; LiWang; ZhentaoMi; YaquanWang

    2004-01-01

    The gas-liquid-liquid reactive extraction system for preparing hydrogen peroxide via anthraquinone was investigated. The oxidation reaction of hydrogenated working solution was combined with the extraction of hydrogen peroxide from working solution in a sieve plate column. The reaction of 2-ethylanthrahydroquionone with oxygen and the liquid-liquid extraction of hydrogen peroxide take place simultaneously. The oxygen was introduced with hydrogenated working solution through a nozzle in the bottom of the column, which worked as agitated air as well as oxidation reagent. The results showed the oxidation and extraction do not hamper each other, on the contrary, the presence of oxidation gas in the column can promote the transfer of hydrogen peroxide fi'om organic phase to aqueous phase, thus the reaction efficiency and extraction efficiency increased with increasing gas superficial velocity. Furthermore, the oxidation efficiency is almost 100% and the extraction efficiency is higher than 90% in this process.

  1. SnFe2 O4 Nanocrystals as Highly Efficient Catalysts for Hydrogen-Peroxide Sensing.

    Science.gov (United States)

    Lee, Kuan-Ting; Liu, Dai-Ming; Lu, Shih-Yuan

    2016-07-25

    SnFe2 O4 nanocrystals (NC), prepared with a simple one-step carrier-solvent-assisted interfacial reaction process, were developed as highly efficient catalysts for hydrogen peroxide sensing. These NCs, with a size of around 7 nm, served as the sensing catalyst and were decorated onto the pore surfaces of a porous fluorine-doped tin oxide (PFTO) host electrode, prepared from commercial FTO glass with a simple anodic treatment, to form the sensing electrode for hydrogen peroxide. The SnFe2 O4 NCs-loaded PFTO electrode exhibited an ultra-high sensitivity of 1027 mA m(-1)  cm(-2) toward hydrogen peroxide, outperforming Pt NCs-loaded PFTO electrodes. The SnFe2 O4 NCs-loaded PFTO electrode proved a promising relatively low cost, high performance sensing electrode for hydrogen peroxide.

  2. UV-C photolysis of endocrine disruptors. The influence of inorganic peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, Javier, E-mail: fjrivas@unex.es [Departamento de Ingenieria Quimica y Quimica Fisica, Facultad de Ciencias, Avenida de Elvas S/N, 06071 Badajoz (Spain); Gimeno, Olga; Borralho, Teresa; Carbajo, Maria [Departamento de Ingenieria Quimica y Quimica Fisica, Facultad de Ciencias, Avenida de Elvas S/N, 06071 Badajoz (Spain)

    2010-02-15

    Norfloxacin, doxycycline and mefenamic acid have been photolysed with UV-C radiation (254 nm) in the presence and absence of inorganic peroxides (hydrogen peroxide or sodium monopersulfate). Quantum yields in the range (1.1-4.5) x 10{sup -3} mol Einstein{sup -1} indicate the low photo-reactivity of these pharmaceuticals. Inorganic peroxides considerably enhanced the contaminants conversion, although no appreciable mineralization could be obtained. A simplistic reaction mechanism for the hydrogen peroxide promoted experiments allowed for a rough estimation of the rate constant between hydroxyl radicals and norfloxacin (k > 1 x 10{sup 9} M{sup -1} s{sup -1}), doxycycline (k > 1.5 x 10{sup 9} M{sup -1} s{sup -1}) and mefenamic acid (k > 11.0 x 10{sup 9} M{sup -1} s{sup -1}).

  3. Peroxide accumulation and cell death in filamentous fungi induced by contact with a contestant.

    Science.gov (United States)

    Silar, Philippe

    2005-02-01

    Podospora anserina and Coprinopsis cinerea (syn. Coprinus cinereus) are endowed with a defence system able to differentiate self vs. non-self and involving the generation of peroxide. Indeed, they produce peroxide when confronted with a filamentous fungus, only in non-self confrontations. Both species are not able to recognize yeasts and show a differential response to bacteria. The accumulation of peroxides in the ascomycete Podospora anserina requires an NADPH oxidase and a MAP kinase cascade, previously shown to be involved in fruit body formation, cell differentiation and cell degeneration. Confrontation is accompanied by the death of the contestant hyphae only in specific combinations of species. As in animals and plants, data suggest that peroxide is likely involved in signalling rather than playing a direct toxic role. Fungi display more complex behaviours than generally acknowledged, i.e. they are able to recognize potential contestants and built up defence reactions involving evolutionary conserved enzymes.

  4. Glutathione protects liver and kidney tissue from cadmium- and lead-provoked lipid peroxidation

    Directory of Open Access Journals (Sweden)

    Jovanović Jasmina M.

    2013-01-01

    Full Text Available Cd and Pb represent a serious ecological problem due to their soluble nature, their mobility and ability to accumulate in the soil. The exposure to these heavy metals can originate from different sources (drinking water, food, air, and they can make their way into the human body through the respiratory and digestive system. We investigated the effects of glutathione on Cd and Pb accumulation and lipid peroxidation effects in the liver and kidneys of heavy metal intoxicated rats. The content of the marker of lipid peroxidation - malondialdehyde was increased several fold the in tissues of exposed animals, the effects being more pronounced in liver. The treatment of intoxicated animals with glutathione drastically suppressed lipid peroxidation. Our results imply that the application of glutathione may have protective role in heavy metal intoxication by inhibiting lipid peroxidation. However, precaution should be made when it comes to Cd, since it seems that glutathione promoted Cd accumulation in the liver.

  5. Molecular nature of sulfhydryl modification by hydrogen peroxide on type 1 ryanodine receptor

    Institute of Scientific and Technical Information of China (English)

    Hong-mei HAN; Ri-sheng WEI; Anthony F LAI; Chang-cheng YIN

    2006-01-01

    Aim: To elucidate the molecular nature of sulfhydryl modification by hydrogen peroxide on type 1 ryanodine receptor (RyRl). Methods: Rabbit skeletal muscle sarcoplasmic reticulum was treated with hydrogen peroxide, then RyRl complex was isolated. The proteins in the complex were analysed by electrophoresis, Western blot and electron microscopy. Results: (1) Hydrogen peroxide induces inter-subunit cross-linking within the tetrameric RyR1 molecule; (2) in parallel to inter-subunit cross-linking, the RyR1 molecule changes morphology; (3) the chemical and morphological changes are reversible: upon reduction by reducing agents, the RyR1 molecule regains its original state. Conclusion: These findings suggest that the molecular mechanism of RyR1 channe1 activity in sarcoplasmic reticulum regulated by hydrogen peroxide is through inter-subunit cross-linking within the tetrameric RyR1 molecule, which in turn induces structural changes of RyR1.

  6. Baeyer-Villiger oxidation of ketones with hydrogen peroxide catalyzed by Sn-aniline complex

    Institute of Scientific and Technical Information of China (English)

    Qing Hua Zhang; Shou Feng Wang; Zi Qiang Lei

    2007-01-01

    Sn-aniline complex was prepared by a simple procedure. Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline complex.

  7. SIMULTANEOUS REACTION AND LIQUID-LIQUID EXTRACTION IN THE HYDROGEN PEROXIDE PRODUCTION

    Institute of Scientific and Technical Information of China (English)

    Shuxiang L(u); Li Wang; Zhentao Mi; Yaquan Wang

    2004-01-01

    The gas-liquid-liquid reactive extraction system for preparing hydrogen peroxide via anthraquinone was investigated. The oxidation reaction of hydrogenated working solution was combined with the extraction of hydrogen peroxide from working solution in a sieve plate column. The reaction of 2-ethylanthrahydroquionone with oxygen and the liquid-liquid extraction of hydrogen peroxide take place simultaneously. The oxygen was introduced with hydrogenated working solution through a nozzle in the bottom of the column, which worked as agitated air as well as oxidation reagent. The results showed the oxidation and extraction do not hamper each other, on the contrary, the presence of oxidation gas in the column can promote the transfer of hydrogen peroxide from organic phase to aqueous phase, thus the reaction efficiency and extraction efficiency increased with increasing gas superficial velocity. Furthermore, the oxidation efficiency is almost 100% and the extraction efficiency is higher than 90% in this process.

  8. Ground-based Infrared Observations of Water Vapor and Hydrogen Peroxide in the Atmosphere of Mars

    Science.gov (United States)

    Encrenaz, T.; Greathouse, T. K.; Bitner, M.; Kruger, A.; Richter, M. J.; Lacy, J. H.; Bézard, B.; Fouchet, T.; Lefevre, F.; Forget, F.; Atreya, S. K.

    2008-11-01

    Ground-based observations of water vapor and hydrogen peroxide have been obtained in the thermal infrared range, using the TEXES instrument at the NASA Infrared Telescope Facility, for different times of the seasonal cycle.

  9. Capillary electrophoresis-electrochemistry microfluidic system for the determination of organic peroxides

    Science.gov (United States)

    Wang, Joseph; Escarpa, Alberto; Pumera, Martin; Feldman, Jason; Svehla, D. (Principal Investigator)

    2002-01-01

    A microfluidic analytical system for the separation and detection of organic peroxides, based on a microchip capillary electrophoresis device with an integrated amperometric detector, was developed. The new microsystem relies on the reductive detection of both organic acid peroxides and hydroperoxides at -700 mV (vs. Ag wire/AgCl). Factors influencing the separation and detection processes were examined and optimized. The integrated microsystem offers rapid measurements (within 130 s) of these organic-peroxide compounds, down to micromolar levels. A highly stable response for repetitive injections (RSD 0.35-3.12%; n = 12) reflects the negligible electrode passivation. Such a "lab-on-a-chip" device should be attractive for on-site analysis of organic peroxides, as desired for environmental screening and industrial monitoring.

  10. Oxidative aromatization of Hantzsch 1,4-dihydropyridines by aqueous hydrogen peroxide-acetic acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simple method for the oxidative aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved by using hydrogen peroxide as green oxidant and acetic acid as catalyst in aqueous solution.

  11. Computational and Experimental Studies of Phthaloyl Peroxide-Mediated Hydroxylation of Arenes Yield a More Reactive Derivative, 4,5-Dichlorophthaloyl Peroxide.

    Science.gov (United States)

    Camelio, Andrew M; Liang, Yong; Eliasen, Anders M; Johnson, Trevor C; Yuan, Changxia; Schuppe, Alex W; Houk, K N; Siegel, Dionicio

    2015-08-21

    The oxidation of arenes by the reagent phthaloyl peroxide provides a new method for the synthesis of phenols. A new, more reactive arene oxidizing reagent, 4,5-dichlorophthaloyl peroxide, computationally predicted and experimentally determined to possess enhanced reactivity, has expanded the scope of the reaction while maintaining a high level of tolerance for diverse functional groups. The reaction proceeds through a novel "reverse-rebound" mechanism with diradical intermediates. Mechanistic insight was achieved through isolation and characterization of minor byproducts, determination of linear free energy correlations, and computational analysis of substituent effects of arenes, each of which provided additional support for the reaction proceeding through the diradical pathway.

  12. The characteristic features of the relationship of thyroid, hemostasis and lipid peroxidation

    Directory of Open Access Journals (Sweden)

    Ольга Федорівна Мисник

    2015-11-01

    Full Text Available In recent years, it is experimentally confirmed the change of activity of blood coagulation factors in hypothyroidism, connection of lipid peroxidation-thyroid (LP-T with hemostasis: T3 inhibits peroxidation in microsomal fraction of hepatocytes thyroliberyn limits the accumulation of LP products, concentration of enzymes-antioxidant varies at different stages of thyroid lesions, especially in thyroid oncology - accumulation of LP products. This indicates that the thyroid regulates the LP processes and its operation depends on the LP

  13. AB Initio calculations of thermodynamic parameters of lithium, sodium and potassium peroxides

    Science.gov (United States)

    Zhuravlev, Yu. N.; Aleinikova, M. V.; Korabelnikov, D. V.

    2012-11-01

    Using a linear combination of atomic orbitals within the CRYSTAL09 software code, the oscillation frequencies of the atoms of lithium, sodium, and potassium peroxides are calculated. In a quasiharmonic approximation of the Debye model, the thermodynamic potentials, entropy, thermal capacity, and the coefficient of thermal expansion are calculated, and their dependence on pressure and temperature is investigated. Using sodium peroxide as an example, the critical point for the sublimation process is found.

  14. Peroxide bleaching agent effects on enamel surface microhardness, roughness and morphology

    OpenAIRE

    2004-01-01

    The aim of this study was to evaluate the surface roughness, microhardness and morphology of human enamel exposed to six bleaching agents (at baseline and post-treatment). Human dental enamel samples were obtained from human third molars and randomly divided into seven groups (n = 11): control, Whiteness Perfect - 10% carbamide peroxide (10% CP), Colgate Platinum - 10% CP, Day White 2Z - 7.5% hydrogen peroxide (7.5% HP), Whiteness Super - 37% CP, Opalescence Quick - 35% CP and Whiteness HP - ...

  15. Membrane Lipid Peroxidation in Copper Alloy-Mediated Contact Killing of Escherichia coli

    OpenAIRE

    Hong,Robert; Kang, Tae Y.; Michels, Corinne A.; Gadura, Nidhi

    2012-01-01

    Copper alloy surfaces are passive antimicrobial sanitizing agents that kill bacteria, fungi, and some viruses. Studies of the mechanism of contact killing in Escherichia coli implicate the membrane as the target, yet the specific component and underlying biochemistry remain unknown. This study explores the hypothesis that nonenzymatic peroxidation of membrane phospholipids is responsible for copper alloy-mediated surface killing. Lipid peroxidation was monitored with the thiobarbituric acid-r...

  16. Lipid peroxidation - inhibitory effects of perioperatively used drugs associated with their membrane interactions.

    OpenAIRE

    Tsuchiya, Hironori

    2014-01-01

    Objective: Oxidative/nitrative stress, an imbalance between oxidant production and antioxidant defense in the biological system, is induced not only by various diseases but also by anesthesia and surgical trauma. Since the choice of drugs is expected to reduce oxidative/nitrative stress in the perioperative period, the lipid peroxidation inhibition by different drugs associated with surgery was studied together with investigating one of their possible mechanisms.Methods: Lipid peroxidation-in...

  17. Gingival bleeding reduction using a carbamide peroxide based tooth paste with lactoperoxidase

    OpenAIRE

    2011-01-01

    Introduction: The combination of carbamide peroxide, thiocyanate or enzymes such as amynoglucosidase or gluco-oxidase is able to reduce gingival inflammation. Objective: To evaluate antiseptic efficacy, in relation to reduced gingival bleeding, of a new dentifrice containing carbamide peroxide and lactorperoxidase. Materials and method: A sample of 32 patients, with periodontal pockets of more than 3mm in the vestibular area and 4 mm at interproximal...

  18. Magnetic carbon xerogels for the catalytic wet peroxide oxidation of 4-nitrophenol solutions

    OpenAIRE

    Ribeiro, R.; Silva, Adrián; Faria, Joaquim; Gomes, Helder

    2015-01-01

    Catalytic wet peroxide oxidation (CWPO) is a well-known advanced oxidation process for the removal of organic pollutants from industrial process waters and wastewater. Specifically, CWPO employs hydrogen peroxide (H2O2) as oxidation source and a suitable catalyst to promote its decomposition via formation of hydroxyl radicals (HO•), which exhibit high oxidizing potential and serve as effective species in the destruction of a huge range of organic pollutants

  19. Effect of Exogenous Application of Hydrogen Peroxide on Drought Tolerance of Glob Amaranth (Gomphrena globosa L.

    Directory of Open Access Journals (Sweden)

    M Goldani

    2012-12-01

    Full Text Available Drought is one of the important environmental stresses that reduce the crop growth. Oxidative stress is a secondary stress due to drought and other abiotic stresses. In order to study the effect of exogenous application of hydrogen peroxide on drought tolerance of glob amaranth (Gomphrena globosa L., an experiment was conducted in greenhouse conditions. This study was designed as factorial based on completely randomized design with 3 replications. Different concentrations of hydrogen peroxide (0, 2.5 and 5 mM and three levels of irrigation intervals (after 4, 7 and 10 days were treated in this study. The results showed that foliar application of hydrogen peroxide can improve shoot and root dry weight and alleviate adverse effects of drought stress. With increasing drought stress stomatal conductance, flower number, total chlorophyll and root volume decreased significantly. So that the lowest of these characterestics was in the irrigation after 10 days. Interaction effects of drought and hydrogen peroxide in shoot dry weight was significantly different in 5% level and in electrolyte leakage, relative water content, free proline and total root length was significantly different in 1% level. In control (4 day irrigation interval with increasing hydrogen peroxide of 2.5 mM, shoot dry weight and total root length increased 20% and 91%, respectively. In control, with increasing hydrogen peroxide to 5 mM total chlorophyll was increased 30.8% compared to 0 mM hydrogen peroxide application (control. The final result showed that foliar application of hydrogen peroxide decreased the adverse effects of drought stress.

  20. Relationship between parameters of lipid peroxidation during obstructive jaundice and after bile flow restoration.

    Science.gov (United States)

    Dudnik, L B; Tsupko, A N; Shupik, M A; Akhaladze, G G; Galperin, E I; Latonova, L V; Pantaz, E A; Alessenko, A V

    2008-01-01

    Restoration of bile flow after 9-day cholestasis in rat liver normalized the content of lipid peroxidation products. The removal of the cholestatic factor after 12-day cholestasis was not followed by recovery of these parameters. We showed that measurement of serum concentration of lipid peroxidation products in patients with cholelithiasis during the preoperative period holds promise for selection of the optimum time for surgical treatment and prediction of the risk of postoperative complications.

  1. The application of catalase for the elimination of hydrogen peroxide residues after bleaching of cotton fabrics

    Directory of Open Access Journals (Sweden)

    AMORIM ALEXANDRA M.

    2002-01-01

    Full Text Available Results of dyeing of cotton fabrics with a bifunctional reactive dye were significantly improved when the fabric after bleaching with hydrogen peroxide was treated with catalase for the elimination of hydrogen peroxide residues from the fabrics. Compared to processes with a varying number of washing steps, with and without commercial reducing agents, the consumption of water could be significantly reduced, without altering the final color shade.

  2. Intermediate Tyrosyl Radical and Amyloid Structure in Peroxide-Activated Cytoglobin.

    Science.gov (United States)

    Ferreira, Juliana C; Marcondes, Marcelo F; Icimoto, Marcelo Y; Cardoso, Thyago H S; Tofanello, Aryane; Pessoto, Felipe S; Miranda, Erica G A; Prieto, Tatiana; Nascimento, Otaciro R; Oliveira, Vitor; Nantes, Iseli L

    2015-01-01

    We characterized the peroxidase mechanism of recombinant rat brain cytoglobin (Cygb) challenged by hydrogen peroxide, tert-butylhydroperoxide and by cumene hydroperoxide. The peroxidase mechanism of Cygb is similar to that of myoglobin. Cygb challenged by hydrogen peroxide is converted to a Fe4+ oxoferryl π cation, which is converted to Fe4+ oxoferryl and tyrosyl radical detected by direct continuous wave-electron paramagnetic resonance and by 3,5-dibromo-4-nitrosobenzene sulfonate spin trapping. When organic peroxides are used as substrates at initial reaction times, and given an excess of peroxide present, the EPR signals of the corresponding peroxyl radicals precede those of the direct tyrosyl radical. This result is consistent with the use of peroxide as a reducing agent for the recycling of Cygb high-valence species. Furthermore, we found that the Cygb oxidation by peroxides leads to the formation of amyloid fibrils. This result suggests that Cygb possibly participates in the development of degenerative diseases; our findings also support the possible biological role of Cygb related to peroxidase activity.

  3. Intermediate Tyrosyl Radical and Amyloid Structure in Peroxide-Activated Cytoglobin.

    Directory of Open Access Journals (Sweden)

    Juliana C Ferreira

    Full Text Available We characterized the peroxidase mechanism of recombinant rat brain cytoglobin (Cygb challenged by hydrogen peroxide, tert-butylhydroperoxide and by cumene hydroperoxide. The peroxidase mechanism of Cygb is similar to that of myoglobin. Cygb challenged by hydrogen peroxide is converted to a Fe4+ oxoferryl π cation, which is converted to Fe4+ oxoferryl and tyrosyl radical detected by direct continuous wave-electron paramagnetic resonance and by 3,5-dibromo-4-nitrosobenzene sulfonate spin trapping. When organic peroxides are used as substrates at initial reaction times, and given an excess of peroxide present, the EPR signals of the corresponding peroxyl radicals precede those of the direct tyrosyl radical. This result is consistent with the use of peroxide as a reducing agent for the recycling of Cygb high-valence species. Furthermore, we found that the Cygb oxidation by peroxides leads to the formation of amyloid fibrils. This result suggests that Cygb possibly participates in the development of degenerative diseases; our findings also support the possible biological role of Cygb related to peroxidase activity.

  4. Synthesis of Covalently Cross-Linked Colloidosomes from Peroxidized Pickering Emulsions

    Directory of Open Access Journals (Sweden)

    Nadiya Popadyuk

    2016-10-01

    Full Text Available A new approach to the formation of cross-linked colloidosomes was developed on the basis of Pickering emulsions that were stabilized exclusively by peroxidized colloidal particles. Free radical polymerization and a soft template technique were used to convert droplets of a Pickering emulsion into colloidosomes. The peroxidized latex particles were synthesized in the emulsion polymerization process using amphiphilic polyperoxide copolymers poly(2-tert-butylperoxy-2-methyl-5-hexen-3-ine-co-maleic acid (PM-1-MAc or poly[N-(tert-butylperoxymethylacrylamide]-co-maleic acid (PM-2-MAc, which were applied as both initiators and surfactants (inisurfs. The polymerization in the presence of the inisurfs results in latexes with a controllable amount of peroxide and carboxyl groups at the particle surface. Peroxidized polystyrene latex particles with a covalently grafted layer of inisurf PM-1-MAc or PM-2-MAc were used as Pickering stabilizers to form Pickering emulsions. A mixture of styrene and/or butyl acrylate with divinylbenzene and hexadecane was applied as a template for the synthesis of colloidosomes. Peroxidized latex particles located at the interface are involved in the radical reactions of colloidosomes formation. As a result, covalently cross-linked colloidosomes were obtained. It was demonstrated that the structure of the synthesized (using peroxidized latex particles colloidosomes depends on the amount of functional groups and pH during the synthesis. Therefore, the size and morphology of colloidosomes can be controlled by latex particle surface properties.

  5. Enhanced stability of hydrogen peroxide in the presence of subsurface solids

    Science.gov (United States)

    Watts, Richard J.; Finn, Dennis D.; Cutler, Lynn M.; Schmidt, Jeremy T.; Teel, Amy L.

    2007-05-01

    The stabilization of hydrogen peroxide was investigated as a basis for enhancing its downgradient transport and contact with contaminants during catalyzed H 2O 2 propagations (CHP) in situ chemical oxidation (ISCO). Stabilization of hydrogen peroxide was investigated in slurries containing four characterized subsurface solids using phytate, citrate, and malonate as stabilizing agents after screening ten potential stabilizers. The extent of hydrogen peroxide stabilization and the most effective stabilizer were solid-specific; however, phytate was usually the most effective stabilizer, increasing the hydrogen peroxide half-life to as much as 50 times. The degree of stabilization was nearly as effective at 10 mM concentrations as at 250 mM or 1 M concentrations. The effect of stabilization on relative rates of hydroxyl radical activity varied between the subsurface solids, but citrate and malonate generally had a greater positive effect than phytate. The effect of phytate, citrate, and malonate on the relative rates of superoxide generation was minimal to somewhat negative, depending on the solid. The results of this research demonstrate that the stabilizers phytate, citrate, and malonate can significantly increase the half-life of hydrogen peroxide in the presence of subsurface solids during CHP reactions while maintaining a significant portion of the reactive oxygen species activity. Use of these stabilizers in the field will likely improve the delivery of hydrogen peroxide and downgradient treatment during CHP ISCO.

  6. Antioxidant and anti-lipid peroxidation activities of Tamarindus indica seed coat in human fibroblast cells.

    Science.gov (United States)

    Nakchat, Oranuch; Meksuriyen, Duangdeun; Pongsamart, Sunanta

    2014-02-01

    Antioxidant activity and total phenolic content of tamarind seed coat extracts (TSCEs) were compared between the two extracts using boiling-water (TSCE-W) and 70% ethanol (TSCE-E) for extraction. TSCE-W, consisting of the highest phenolic content, possessed 2,2-diphenyl-1 -picrylhydrazyl (DPPH) radical scavenging and anti-lipid peroxidation activities much higher than TSCE-E and Trolox. Additionally, both TSCEs also exhibited superoxide anion and hydrogen peroxide scavenging activities higher than Trolox and BHA. Anti-lipid peroxidation and cytotoxicity of TSCE-W were also studied in human foreskin fibroblast CCD-1064Sk cells. Cytotoxic effect was not observed when exposed to TSCE-W up to 1 mg/mL for 12-48 h. However, TSCE-W significantly attenuated lipid peroxidation in H202-damaged cells. HPLC analysis showed the presence of (+)-catechin, (-)-epicatechin, and procyanidin B2 in TSCE-W, which could be responsible for antioxidant and anti-lipid peroxidation activities. The results suggest that an inexpensive and simple boiling-water extraction of TSCE-W may provide a valuable natural antioxidant source having anti-lipid peroxidation for health food additives, nutraceuticals as well as cosmeceuticals.

  7. Effects of hydrogen peroxide on mitochondrial gene expression of intestinal epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Jian-Ming Li; Qian Cai; Hong Zhou; Guang-Xia Xiao

    2002-01-01

    AIM: To study the effects of hydrogen peroxide on mitochondrial gene expression of intestinal epithelial cells in in vitro model of hydrogen peroxide-stimulated SW-480 cells.METHODS: RNA of hydrogen peroxide-induced SW-480 cells was isolated, and reverse-transcriptional polymerase chain reaction was performed to study gene expression of ATPase subunit 6, ATPase subunit 8, cytochrome c oxidase subunit Ⅰ (COⅠ), cytochrome coxidase subuit Ⅱ (COⅡ) and cytochrome c oxidase subunit Ⅲ (COⅢ). Mitochondria were isolated and activities of mitochondrial cytochrome c oxidase and ATPase were also measured simultaneously.RESULTS: Hydrogen peroxide led to differential expression of mitochondrial genes with some genes up-regulated or down-regulated in a dose dependent manner. Differences were very obvious in expressions of mitochondrial genes of cells treated with hydrogen peroxide in a concentration of 400 μmol/L or 4 mmol/L. In general, differential expression of mitochondrial genes was characterized by up-regulation of mitochondrial genes in the concentration of 400 μmol/L and down-regulation in the concentration of 4 mmol/L. In consistence with changes in mitochondrial gene expressions, hydrogen peroxide resulted in decreased activities of cytochrome c oxidase and ATPase.CONCLUSIONS: The differential expression of mitochondrial genes encoding cytochrome c oxidase and ATPase is involved in apoptosis of intestinal epithelial cells by affecting activities of cytochorme c oxidase and ATPase.

  8. MODIFIED OPAL: A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

    Institute of Scientific and Technical Information of China (English)

    XuerenQian; XianhuiAn; WenboLiu; GangYu; ZhanqianSong

    2004-01-01

    The possibility of modified opal as the stabilizer ofhydrogen peroxide bleaching was investigated. Theresults showed that the modified opal in place ofsodium silicate as the stabilizer of hydrogen peroxidebleaching is feasible. At the same dosage, above 3%ISO can be increased for both wheat straw pulp anddeinked pulp. The stabilizing ability of the modifiedopal to hydrogen peroxide bleaching of pulp isimproved markedly. It is favorable for bleaching toincrease temperature and time within a permissiveextent. The suitable process conditions are I0% ofpulp consistency, 3% of hydrogen peroxide, 1.5% ofsodium hydroxide, 3% of the modified opal, 70~"and 60 min when the modified opal is used as thestabilizer of hydrogen peroxide bleaching. At theseconditions, the brightness gain can reach about 16%ISO for wheat straw pulp. In addition, it is favorablefor bleaching to add a little magnesium sulfate whenthe modified opal is used as the stabilizer ofhydrogen peroxide bleaching, the brightness of pulpcan increase 1%ISO if0.05% of magnesium sulfate isadded. The cost analysis indicated that the modifiedopal is superior to sodium silicate as the stabilizer ofhydrogen peroxide bleaching in economical aspectand has further the potential of market development.

  9. Study on Mechanism of Soy Protein Oxidation Induced by Lipid Peroxidation Products

    Directory of Open Access Journals (Sweden)

    Wei Wu

    2013-01-01

    Full Text Available Oxidative modification of soy protein by lipid peroxidation products, which was potentially present in a lipoxygenase-catalyzed polyunsaturated fatty acid peroxidation system, was investigated in this study. 13S-Hydroperoxy-9Z, 11E-Octadecadienoic acid (HPODE, malondialdehyde and acrolein were selected as representative primary product and secondary byproducts of lipid peroxidation and 2, 2’-azobis-(2-amidinopropane dihydrochloride (AAPH -derived peroxyl radical peroxyl radicals were chosen to simulate lipid peroxidation-derived free radical. Incubation of soy protein with increasing concentration of AAPH, HPODE, malondialdehyde and acrolein resulted in gradual generation of protein carbonyl derivatives, loss of free sulphydryl groups, total sulphydryl groups, free amine, available lysine, surface hydrophobicity and formation of oxidation aggregates. The average distribution model of protein accessible groups could explain majority mechanism of lipid peroxidation products-mediated soy protein oxidation. Primary oxidation aggregates further developed into insoluble aggregates by covalent cross-linking also may provide a partial mechanism of lipid peroxidation products-mediated soy protein oxidation.

  10. In situ oxidation remediation technologies: kinetic of hydrogen peroxide decomposition on soil organic matter.

    Science.gov (United States)

    Romero, Arturo; Santos, Aurora; Vicente, Fernando; Rodriguez, Sergio; Lafuente, A Lopez

    2009-10-30

    Rates of hydrogen peroxide decomposition were investigated in soils slurries. The interaction soil-hydrogen peroxide was studied using a slurry system at 20 degrees C and pH 7. To determine the role of soil organic matter (SOM) in the decomposition of hydrogen peroxide, several experiments were carried out with two soils with different SOM content (S1=15.1%, S2=10%). The influence of the oxidant dosage ([H2O2](o) from 10 to 30 g L(-1) and soil weight to liquid phase volume ratio=500 g L(-1)) was investigated using the two calcareous loamy sand soil samples. The results showed a rate dependency on both SOM and hydrogen peroxide concentration being the H2O2 decomposition rate over soil surface described by a second-order kinetic expression r(H2O2) = -dn(H2O2) / W(SOM) dt = kC(H2O2) C(SOM). Thermogravimetric analysis (TGA) was used to evaluate the effect caused by the application of this oxidant on the SOM content. It was found a slightly increase of SOM content after treatment with hydrogen peroxide, probably due to the incorporation of oxygen from the oxidant (hydrogen peroxide).

  11. Comparing the Effect of Different Bleaching Regims of Carbamide Peroxide on Microhardness of Z250 Composite

    Directory of Open Access Journals (Sweden)

    B Esmaeili

    2015-11-01

    Full Text Available Introduction: Bleaching products with oxidizing mechanism can exert side effects on the restorative materials existing in the oral cavity. Since bleaching agents are applied in different concentrations, the present study aimed to compare the effect of different bleaching regims of carbamide peroxide on microhardness of Z250 microhybride composite. Methods: In this in vitro study , 32 specimens of micro hybride composite (Z250 were made which were randomly divided into 4 subgroups (n=8: G1: bleached with10% carbamide peroxide 4 hours a day for 2 weeks G2: bleached with 16%carbamide peroxide 3 hours a day for 2 weeks G3: bleached with 22%carbamide peroxide 1hour a day for 2 weeks G4: the control subgroup stored in distilled water at 37◦c for 2 weeks. Microhardness of specimens was measured before and after bleaching using Vickers hardness testing machine. Moreover, the study data were analyzed statistically applying Anova and t-test (&alpha= 0.05. Results: This study findings revealed that using bleaching agent significantly decreased the  microhardness of composite resin in the bleaching groups compared to the control group, though the concentration of carbamide peroxide produced no significant effect on the microhardness value. (p>0.13 Conclusion: Bleaching therapy can cause a reduction in microhardness of Z250 composite and different concentrations of carbamide peroxide can reduce microhardness of Z250 to the same value.

  12. Protection against hydrogen peroxide induced oxidative damage in rat erythrocytes by Mangifera indica L. peel extract.

    Science.gov (United States)

    Ajila, C M; Prasada Rao, U J S

    2008-01-01

    Phytochemicals such as polyphenols and carotenoids are gaining importance because of their contribution to human health and their multiple biological effects such as antioxidant, antimutagenic, anticarcinogenic and cytoprotective activities and other therapeutic properties. Mango peel is a major by-product in pulp industry and it contains various bioactive compounds like polyphenols, carotenoids and others. In the present study, the protective effect of peel extracts of unripe and ripe mango fruits of two varieties namely, Raspuri and Badami on hydrogen peroxide induced hemolysis, lipid peroxidation, degradation of membrane proteins and its morphological changes are reported. The oxidative hemolysis of rat erythrocytes by hydrogen peroxide was inhibited by mango peel extract in a dose dependent manner. The IC(50) value for lipid peroxidation inhibition on erythrocyte ghost membrane was found to be in the range of 4.5-19.3 microg gallic acid equivalents. The mango peel extract showed protection against membrane protein degradation caused by hydrogen peroxide. Morphological changes to erythrocyte membrane caused by hydrogen peroxide were protected by mango peel extract. The results demonstrated that mango peel extracts protected erythrocytes against oxidative stress and may impart health benefits and it could be used as a valuable food ingredient or a nutraceutical product.

  13. ChinAfrica briefly introduces the latest Chinese Government regulations

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Flour Additives Banned Two food additives, benzoyl peroxide and calcium peroxide, are prohibited from flour production starting May I, according to a statement issued by China's Ministry of Health on March 1.

  14. Salinity-gradient energy driven microbial electrosynthesis of hydrogen peroxide

    Science.gov (United States)

    Li, Xiaohu; Angelidaki, Irini; Zhang, Yifeng

    2017-02-01

    Hydrogen peroxide (H2O2) as a strong oxidant, is widely used in various chemical industries and environmental remediation processes. In this study, we developed an innovative method for cost-effective production of H2O2 by using a microbial reverse-electrodialysis electrolysis cell (MREC). In the MREC, electrical potential generated by the exoelectrogens and the salinity-gradient between salt and fresh water were utilized to drive the high-rate H2O2 production. Operational parameters such as air flow rate, pH, cathodic potential, flow rate of salt and fresh water were investigated. The optimal H2O2 production was observed at salt and fresh water flow rate of 0.5 mL min-1, air flow rate of 12-20 mL min-1, cathode potential of -0.485 ± 0.025 V (vs Ag/AgCl). The maximum H2O2 accumulated concentration of 778 ± 11 mg L-1 was obtained at corresponding production rate of 11.5 ± 0.5 mg L-1 h-1. The overall energy input for the synthesis process was 0.45 ± 0.03 kWh kg-1 H2O2. Cathode potential was the key factor for H2O2 production, which was mainly affected by the air flow rate. This work for the first time proved the potential of MREC as an efficient platform technology for simultaneous electrosynthesis of valuable chemicals and utilization of salinity-gradient energy.

  15. Hydrogen peroxide regulated photosynthesis in C4-pepc transgenic rice.

    Science.gov (United States)

    Ren, C G; Li, X; Liu, X L; Wei, X D; Dai, C C

    2014-01-01

    In this study, we investigated the photosynthetic physiological basis in 'PC' transgenic rice (Oryza sativa L.), showing high-level expression of the gene encoding C4 phosphoenolpyruvate carboxylase (pepc), by hydrogen peroxide (H2O2). The C4-PEPC gene (pepc) from maize in the transgenic rice plants was checked by PCR. Comparison of yield components and photosynthetic indices between PC and untransformed wild-type (WT) plants indicated that increased yield in PC was associated with higher net photosynthetic rate and higher activities of phosphoenolpyruvate carboxylase (PEPC). Both PC and WT plants were treated with 1 mmol L(-1) abscisic acid (ABA), 0.04% 1-butanol (BA), 2 mmol L(-1) neomycin (NS), or 2 mmol L(-1) diphenyleneiodonium chloride (DPI) to investigate the relationship between photosynthesis and levels of H2O2 and phosphatidic acid. In both PC and WT, ABA induced H2O2 generation and simultaneous decrease in stomatal conductance (g(s)). PC plants treated with BA showed decreased H2O2 content and strongly increased g(s) within 2 h of treatment. Similar results were observed in response to DPI treatment in PC. However, WT did not observe the decrease of H2O2 during the treatments of BA and DPI. The reduced H2O2 content in PC caused by BA treatment differed to that induced by DPI because BA did not inhibit NADPH oxidase activities. While BA induced a larger PEPC activity in PC, and higher catalase activity as well. These results indicated that the regulation of endogenous H2O2 metabolism of PC could be helpful for enhancing photosynthetic capability.

  16. Effects of Hydrogen Peroxide on Coral Photosynthesis and Calcification

    Science.gov (United States)

    Higuchi, T.; Fujimura, H.; Arakaki, T.; Oomori, T.

    2007-12-01

    The widely-observed decline of coral reefs is considered to be caused by changes in the environment by natural and anthropogenic activities. As one important factor, the run-off of various matters from human activities to the coastal seawater poses stresses to the corals by degrading the quality of the seawater. In Okinawa, Japan, red- soil running off from the developed land has been a major environmental issue since 1980s. Hydrogen peroxide (HOOH), a strong active oxygen species, is one of the photochemically formed chemicals in the red-soil-polluted seawater. Recent photochemical studies of seawater showed that HOOH photo-formation was faster in the red- soil-polluted seawater than clean seawater. We studied the effects of HOOH on corals by studying the changes in coral carbon metabolisms such as photosynthesis and calcification, which are indicators of the physiological state of a coral colony. The corals were exposed to various concentrations of HOOH (0, 0.3, 3 μM). Two massive coral species of Porites sp. and Goniastrea aspera and one branch coral of Galaxea facicularis were used for the exposure experiments. The control experiments showed that when no HOOH was added, metabolisms of each coral colony were relatively stable. On the other hand, when HOOH was added to the seawater, we observed obvious changes in the coral metabolisms in all the coral species. When 0.3 μM HOOH was added, photosynthesis decreased by 14% and calcification decreased by 17% within 3 days, compared with the control. When 3 μM HOOH was added, photosynthesis decreased by 21% and calcification decreased by 41% within 3 days, compared with the control. Our study showed that higher concentrations of HOOH posed more stress to the coral colonies.

  17. Shock initiation studies on high concentration hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, Stephen A [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Stahl, David B [Los Alamos National Laboratory; Gibson, L. Lee [Los Alamos National Laboratory; Bartram, Brian D. [Los Alamos National Laboratory

    2009-01-01

    Concentrated hydrogen peroxide (H{sub 2}O{sub 2}) has been known to detonate for many years. However, because of its reactivity and the difficulty in handling and confining it, along with the large critical diameter, few studies providing basic information about the initiation and detonation properties have been published. We are conducting a study to understand and quantify the initiation and detonation properties of highly concentrated H{sub 2}O{sub 2} using a gas-driven two-stage gun to produce well defined shock inputs. Multiple magnetic gauges are used to make in-situ measurements of the growth of reaction and subsequent detonation in the liquid. These experiments are designed to be one-dimensional to eliminate any difficulties that might be encountered with large critical diameters. Because of the concern of the reactivity of the H{sub 2}O{sub 2} with the confining materials, a remote loading system has been developed. The gun is pressurized, then the cell is filled and the experiment shot within less than three minutes. TV cameras are attached to the target so the cell filling can be monitored. Several experiments have been completed on {approx}98 wt % H{sub 2}O{sub 2}/H{sub 2}O mixtures; initiation has been observed in some experiments that shows homogeneous shock initiation behavior. The initial shock pressurizes and heats the mixture. After an induction time, a thermal explosion type reaction produces an evolving reactive wave that strengthens and eventually overdrives the first wave producing a detonation. From these measurements, we have determined unreacted Hugoniot information, times (distances) to detonation (Pop-plot points) that indicate low sensitivity, and detonation velocities of high concentration H{sub 2}O{sub 2}/H{sub 2}O solutions that agree with earlier estimates.

  18. Hydrogen peroxide stimulates cell motile activity through LPA receptor-3 in liver epithelial WB-F344 cells

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Ayano; Tanabe, Eriko; Inoue, Serina; Kitayoshi, Misaho; Okimoto, Souta; Hirane, Miku; Araki, Mutsumi [Division of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan); Fukushima, Nobuyuki [Division of Molecular Neurobiology, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan); Tsujiuchi, Toshifumi, E-mail: ttujiuch@life.kindai.ac.jp [Division of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan)

    2013-04-12

    Highlights: •Hydrogen peroxide stimulates cell motility of WB-F344 cells. •LPA{sub 3} is induced by hydrogen peroxide in WB-F344 cells. •Cell motility by hydrogen peroxide is inhibited in LPA{sub 3} knockdown cells. •LPA signaling is involved in cell migration by hydrogen peroxide. -- Abstract: Hydrogen peroxide which is one of reactive oxygen species (ROS) mediates a variety of biological responses, including cell proliferation and migration. In the present study, we investigated whether lysophosphatidic acid (LPA) signaling is involved in cell motile activity stimulated by hydrogen peroxide. The rat liver epithelial WB-F344 cells were treated with hydrogen peroxide at 0.1 or 1 μM for 48 h. In cell motility assays, hydrogen peroxide treated cells showed significantly high cell motile activity, compared with untreated cells. To measure the expression levels of LPA receptor genes, quantitative real time RT-PCR analysis was performed. The expressions of LPA receptor-3 (Lpar3) in hydrogen peroxide treated cells were significantly higher than those in control cells, but not Lpar1 and Lpar2 genes. Next, to assess the effect of LPA{sub 3} on cell motile activity, the Lpar3 knockdown cells from WB-F344 cells were also treated with hydrogen peroxide. The cell motile activity of the knockdown cells was not stimulated by hydrogen peroxide. Moreover, in liver cancer cells, hydrogen peroxide significantly activated cell motility of Lpar3-expressing cells, but not Lpar3-unexpressing cells. These results suggest that LPA signaling via LPA{sub 3} may be mainly involved in cell motile activity of WB-F344 cells stimulated by hydrogen peroxide.

  19. Micromorphology and microhardness of enamel after treatment with home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Robson Tetsuo Sasaki

    2009-12-01

    Full Text Available OBJECTIVE: The purpose of this study was to assess the effect of home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide on enamel microhardness and surface micromorphology. MATERIAL AND METHODS: Enamel slabs (n=10 received the bleaching agents for 1 h/day and remained in artificial saliva solution for 23 h/day, during a total period of 21 days. Control group was composed of enamel slabs that were not subjected to treatment with the agents and were maintained in artificial saliva solution. Microhardness tests were performed before treatment application, 21 days of treatment and 14 days after the end of treatment. Scanning electron microscopy analyses were performed after 14 days after the end of bleaching treatment by 3 calibrated observers who attributed scores. RESULTS: The Tukey's test (α=0.05 showed no significant differences in microhardness values among bleaching agents, at 21 days of treatment and a significant increase in microhardness for different agents after 14 days from the end of treatment. Fisher's exact test showed differences in micromorphology of enamel between control and experimental groups (p=0.0342. CONCLUSIONS: Bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide may change surface micromorphology of enamel, although no changes in microhardness were observed.

  20. Peroxide-modified titanium dioxide: a chemical analog of putative Martian soil oxidants

    Science.gov (United States)

    Quinn, R. C.; Zent, A. P.

    1999-01-01

    Hydrogen peroxide chemisorbed on titanium dioxide (peroxide-modified titanium dioxide) is investigated as a chemical analog to the putative soil oxidants responsible for the chemical reactivity seen in the Viking biology experiments. When peroxide-modified titanium dioxide (anatase) was exposed to a solution similar to the Viking labeled release (LR) experiment organic medium, CO2 gas was released into the sample cell headspace. Storage of these samples at 10 degrees C for 48 hr prior to exposure to organics resulted in a positive response while storage for 7 days did not. In the Viking LR experiment, storage of the Martian surface samples for 2 sols (approximately 49 hr) resulted in a positive response while storage for 141 sols essentially eliminated the initial rapid release of CO2. Heating the peroxide-modified titanium dioxide to 50 degrees C prior to exposure to organics resulted in a negative response. This is similar to, but not identical to, the Viking samples where heating to approximately 46 degrees C diminished the response by 54-80% and heating to 51.5 apparently eliminated the response. When exposed to water vapor, the peroxide-modified titanium dioxide samples release O2 in a manner similar to the release seen in the Viking gas exchange experiment (GEx). Reactivity is retained upon heating at 50 degrees C for three hours, distinguishing this active agent from the one responsible for the release of CO2 from aqueous organics. The release of CO2 by the peroxide-modified titanium dioxide is attributed to the decomposition of organics by outer-sphere peroxide complexes associated with surface hydroxyl groups, while the release of O2 upon humidification is attributed to more stable inner-sphere peroxide complexes associated with Ti4+ cations. Heating the peroxide-modified titanium dioxide to 145 degrees C inhibited the release of O2, while in the Viking experiments heating to this temperature diminished but did not eliminated the response. Although the

  1. Spiro-oxindole derivative 5-chloro-4',5'-diphenyl-3'-(4-(2-(piperidin-1-yl) ethoxy) benzoyl) spiro[indoline-3,2'-pyrrolidin]-2-one triggers apoptosis in breast cancer cells via restoration of p53 function.

    Science.gov (United States)

    Saxena, Ruchi; Gupta, Garima; Manohar, Murli; Debnath, Utsab; Popli, Pooja; Prabhakar, Yenamandra S; Konwar, Rituraj; Kumar, Sandeep; Kumar, Atul; Dwivedi, Anila

    2016-01-01

    Breast cancer remains a significant health problem due to the involvement of multiple aberrant and redundant signaling pathways in tumorigenesis and the development of resistance to the existing therapeutic agents. Therefore, the search for novel chemotherapeutic agents for effective management of breast cancer is still warranted. In an effort to develop new anti-breast cancer agents, we have synthesized and identified novel spiro-oxindole derivative G613 i.e. 5-chloro-4',5'-diphenyl-3'-(4-(2-(piperidin-1-yl) ethoxy) benzoyl) spiro[indoline-3,2'-pyrrolidin]-2-one, which has shown growth inhibitory activity in breast cancer cells. The present study was aimed to explore the mechanism of anti-tumorigenic action of this newly identified spiro-oxindole compound. Compound G613 inhibited the Mdm2-p53 interaction in breast cancer cells and tumor xenograft. It caused restoration of p53 function by activating its promoter activity, triggering its nuclear accumulation and preventing its ubiquitination and proteasomal degradation. Supportively, molecular docking studies revealed considerable homology in the docking mode of G613 and the known Mdm2 inhibitor Nutlin-3, to p53 binding pocket of Mdm2. The activation of p53 led to upregulation of p53 dependent pro-apoptotic proteins, Bax, Pumaα and Noxa and enhanced interaction of p53 with bcl2 member proteins thus triggering both transcription-dependent and transcription-independent apoptosis, respectively. Additionally, the compound decreased estrogen receptor activity through sequestration of estrogen receptor α by p53 thereby causing a decreased transcriptional activation and expression of proliferation markers. In conclusion, G613 represents a potent small-molecule inhibitor of the Mdm2-p53 interaction and can serve as a promising lead for developing a new class of anti-cancer therapy for breast cancer patients.

  2. Upregulation of DR5 receptor by the diaminothiazole DAT1 [4-amino-5-benzoyl-2-(4-methoxy phenyl amino) thiazole] triggers an independent extrinsic pathway of apoptosis in colon cancer cells with compromised pro and antiapoptotic proteins.

    Science.gov (United States)

    Thomas, Sannu A; Vasudevan, Smreti; Thamkachy, Reshma; Lekshmi, Swathi U; Santhoshkumar, Thankayyan R; Rajasekharan, Kallikat N; Sengupta, Suparna

    2013-06-01

    Mitochondria mediated signalling is the more common way of apoptosis induction exhibited by many chemotherapeutic agents in cancer cells. Death receptor mediated signalling for apoptosis in many cells also requires further amplification from the mitochondrial pathway activation through tBid. Thus the potential of most chemotherapeutic agents in tumours with intrinsic apoptosis resistance due to changes in molecules involved in the mitochondrial pathway is limited. Diaminothiazoles were shown earlier to bind to tubulin thereby exhibiting cytotoxicity towards different cancer cells. We observed that the lead diaminothiazole, DAT1 [4-amino-5-benzoyl-2-(4-methoxy phenyl amino) thiazole] could induce apoptosis in the colon cancer cell line HCT116 by both pathways. However, in contrast to many other chemotherapeutic agents, DAT1 triggered apoptosis where the intrinsic pathway was blocked by changing the pro and antiapoptotic proteins. An independent extrinsic pathway activation triggered by the upregulation of DR5 receptor accounted for that. The induction of DR5 occurred in the transcriptional level and the essential role of DR5 was confirmed by the fact that siRNA downregulation of DR5 significantly reduced DAT1 induced apoptosis. HCT116 cells were earlier shown to have a type II response for apoptosis induction where extrinsic pathway was connected to the intrinsic pathway via the mediator protein tBid. Our finding thus indicates that the signalling events in the manifestation of apoptosis depend not only on the cancer cell type, but also on the inducer. Our results also place diaminothiazoles in a promising position in the treatment of tumours with compromised apoptotic factors.

  3. 过氧化苯甲酰联合多磺酸黏多糖对寻常痤疮患者血清性激素水平、免疫指标的影响%Effect of benzoyl peroxide combining with Hirudoid on serum sex hormone levels, immune index of patients with acne vulgaris

    Institute of Scientific and Technical Information of China (English)

    李琳; 孙婕; 虞伟衡; 胡贇皓

    2015-01-01

    目的:观察过氧化苯甲酰联合多磺酸黏多糖对寻常痤疮患者血清性激素水平、免疫指标的影响.方法:将185例纳入研究的重度寻常痤疮患者抽签分为观察组(85例)和对照组(80例),观察组给予过氧化苯甲酰联合多磺酸黏多糖外用治疗,对照组仅给予过氧化苯甲酰,治疗2个月,观察性激素(T、FSH、LH、E2)及免疫指标(IgG、IgA、IgM、C3、C4、IL-2、sIL-2R)的变化.结果:观察组治疗后IgG、C3、C4、IL-2与本组治疗前比较下降明显,差异有统计学意义(P<0.05),对照组所有指标变化不明显,差异无统计学意义(P>0.05);两组治疗后IgG、C3、C4、IL-2水平比较,差异均有统计学意义(P<0.05).两组治疗前后性激素各指标比较,差异均无统计学意义(P>0.05).结论:过氧化苯甲酰联合多磺酸黏多糖方案对寻常痤疮患者的免疫功能有一定的影响,治疗作用可能也与此有关,但对性激素无明显影响.

  4. 胶束毛细管电泳在线吹扫富集技术测定面粉中的增白剂过氧化苯甲酰%Determination of Benzoyl Peroxide in Wheat Flour by Micellar Capillary Electrophoresis On-Line Sweeping Concentration Technique

    Institute of Scientific and Technical Information of China (English)

    王全; 杨更亮; 张骊

    2007-01-01

    建立了测定面粉中过氧化苯甲酰含量的一种新方法.面粉用甲醇超声萃取,过滤,直接进样分析.在电泳缓冲液为0.02 mol/L硼砂-硼酸缓冲液(含0.04 mol/L十二烷基硫酸钠)(pH 9.0)、紫外检测波长为214 nm、分离电压为10 kV的条件下,富集倍数可达150倍以上,过氧化苯甲酰的质量浓度和其色谱峰高呈良好的线性关系,过氧化苯甲酰的线性范围为0.002~0.012 g/L(r=0.999 8),最低检测限为2 mg/L.将该法用于面粉中过氧化苯甲酰的分析,样品无需繁琐的预处理过程便可直接定量,缩短了分析周期,简单方便,重现性好.

  5. Induced lipid peroxidation in ram sperm: semen profile, DNA fragmentation and antioxidant status.

    Science.gov (United States)

    Hamilton, Thais Rose dos Santos; de Castro, Letícia Signori; Delgado, Juliana de Carvalho; de Assis, Patrícia Monken; Siqueira, Adriano Felipe Perez; Mendes, Camilla Mota; Goissis, Marcelo Demarchi; Muiño-Blanco, Teresa; Cebrián-Pérez, José Álvaro; Nichi, Marcílio; Visintin, José Antonio; D'Ávila Assumpção, Mayra Elena Ortiz

    2016-04-01

    Action of reactive oxygen species, protamination failures and apoptosis are considered the most important etiologies of sperm DNA fragmentation. This study evaluated the effects of induced lipid peroxidation susceptibility on native semen profile and identified the mechanisms involved in sperm DNA fragmentation and testicular antioxidant defense on Santa Ines ram sperm samples. Semen was collected from 12 adult rams (Ovis aries) performed weekly over a 9-week period. Sperm analysis (motility, mass motility, abnormalities, membrane and acrosome status, mitochondrial potential, DNA fragmentation, lipid peroxidation and intracellular free radicals production); protamine deficiency; PRM1, TNP1 and TNP2 gene expression; and determination of glutathione peroxidase (GPx), glutathione reductase, catalase (CAT) and superoxide dismutase activity and immunodetection in seminal plasma were performed. Samples were distributed into four groups according to the sperm susceptibility to lipid peroxidation after induction with ascorbate and ferrous sulfate (low, medium, high and very high). The results were analyzed by GLM test and post hoc least significant difference. We observed an increase in native GPx activity and CAT immunodetection in groups with high susceptibility to induced lipid peroxidation. We also found an increase in total sperm defects, acrosome and membrane damages in the group with the highest susceptibility to induced lipid peroxidation. Additionally, the low mitochondrial membrane potential, susceptible to chromatin fragmentation and the PRM1 mRNA were increased in the group showing higher susceptibility to lipid peroxidation. Ram sperm susceptibility to lipid peroxidation may compromise sperm quality and interfere with the oxidative homeostasis by oxidative stress, which may be the main cause of chromatin damage in ram sperm.

  6. Nitric oxide consumption through lipid peroxidation in brain cell suspensions and homogenates.

    Science.gov (United States)

    Keynes, Robert G; Griffiths, Charmaine H; Hall, Catherine; Garthwaite, John

    2005-05-01

    Mechanisms which inactivate NO (nitric oxide) are probably important in governing the physiological and pathological effects of this ubiquitous signalling molecule. Cells isolated from the cerebellum, a brain region rich in the NO signalling pathway, consume NO avidly. This property was preserved in brain homogenates and required both particulate and supernatant fractions. A purified fraction of the particulate component was rich in phospholipids, and NO consumption was inhibited by procedures that inhibited lipid peroxidation, namely a transition metal chelator, the vitamin E analogue Trolox and ascorbate oxidase. The requirement for the supernatant was accounted for by its content of ascorbate which catalyses metal-dependent lipid peroxidation. The NO-degrading activity of the homogenate was mimicked by a representative mixture of brain lipids together with ascorbate and, under these conditions, the lipids underwent peroxidation. In a suspension of cerebellar cells, there was a continuous low level of lipid peroxidation, and consumption of NO by the cells was decreased by approx. 50% by lipid-peroxidation inhibitors. Lipid peroxidation was also abolished when NO was supplied at a continuously low rate (approximately 100 nM/min), which explains why NO consumption by this process is saturable. Part of the activity remaining after the inhibition of lipid peroxidation was accounted for by contaminating red blood cells, but there was also another component whose activity was greatly enhanced when the cells were maintained under air-equilibrated conditions. A similar NO-consuming process was present in cerebellar glial cells grown in tissue culture but not in blood platelets or leucocytes, suggesting a specialized mechanism.

  7. Possible role of organic peroxides in the detection of irradiated food

    Energy Technology Data Exchange (ETDEWEB)

    Qi Shengchu; Wu Jilan (Beijing Univ., BJ (China). Dept. of Technical Physics); Zhu Yan (Ministry of Public Health, Beijing (China))

    In order to determine the level of organic peroxides induced by autooxidation, random sampling of pork has been performed. The organic peroxide content in unirradiated pork has been estimated as (5.4 [+-] 3.0) x10[sup -5]mol.kg[sup -1]. The dependence of yield of peroxide in pork, minced meat and braised chicken on absorbed dose has been investigated. For killing trichinae 0.5 [approx] 1 kGy is used, the quantity of peroxide in pork will be 4x10[sup -4] mol.kg[sup -1] for 1 kGy, which is 3.7 [approx] 7.4 times greater than the background. If 3 kGy is used to eliminate Salmonella, the quantity of peroxides in pork will be 1.3 x10[sup -3]mol.kg[sup -1], which approaches 24 times greater than the average value of background. When minced meat was irradiated in the presence of air, a chain reaction took place with G value 30.2. Radiation processing dose of braised chicken for shelf-life extension is [approx] 9kGy, organic peroxide content in braised chicken fat is 32.5 x10[sup -4]mol.kg[sup -1], which is about 14.7 times greater than average value (2.2x10[sup -4]mol.kg[sup -1]) in unirradiated one. Applying the peroxide method to qualitatively detect irradiated food containing fat is satisfactory, if combined with measuring the ESR signal of irradiated bone which will improve the detection method. (author).

  8. The mechanism of catalytic methylation of 2-phenylpyridine using di-tert-butyl peroxide.

    Science.gov (United States)

    Sharma, Akhilesh K; Roy, Dipankar; Sunoj, Raghavan B

    2014-07-14

    The mechanism of palladium chloride-catalyzed direct methylation of arenes with peroxides is elucidated by using the energetics computed at the M06 density functional theory. The introduction of a methyl group by tert-butyl peroxides at the ortho-position of a prototypical 2-phenyl pyridine, a commonly used substrate in directed C-H functionalization reactions, is examined in detail by identifying the key intermediates and transition states involved in the reaction sequence. Different possibilities that differ in terms of the site of catalyst coordination with the substrate and the ensuing mechanism are presented. The important mechanistic events involved are (a) an oxidative or a homolytic cleavage of the peroxide O-O bond, (b) C-H bond activation, (c) C-C bond activation, and (d) reductive elimination involving methyl transfer to the aromatic ring. We have examined both radical and non-radical pathways. In the non-radical pathway, the lowest energy pathway involves C-H bond activation prior to the coordination of the peroxide to palladium, which is subsequently followed by the O-O bond cleavage of the peroxide and the C-C bond activation. Reductive elimination in the resulting intermediate leads to the vital C-C bond formation between methyl and aryl carbon atoms. In the non-radical pathway, the C-C bond activation is higher in energy and has been identified as the rate-limiting step of this reaction. In the radical pathway, however, the activation barrier for the C-C bond cleavage is lower than for the peroxide O-O bond cleavage. A combination of a radical pathway up to the formation of a palladium methyl intermediate and a subsequent non-radical pathway has been identified as the most favored pathway for the title reaction. The predicted mechanism is in good agreement with the experimental observations on PdCl2 catalyzed methylation of 2-phenyl pyridine using tert-butyl peroxide.

  9. Prediction of severe neonatal hyperbilirubinemia using cord blood hydrogen peroxide: a prospective study.

    Directory of Open Access Journals (Sweden)

    Hung-Chieh Chou

    Full Text Available BACKGROUND: We hypothesized that cord blood hydrogen peroxide (H2O2 could be utilized to predict the severity of neonatal hyperbilirubinemia. METHODS: We prospectively enrolled term or near-term healthy neonates. Cord blood and capillary blood at three days of age were measured for hydrogen peroxide and bilirubin concentrations. For newborns with hyperbilirubinemia, further blood samples were obtained at five and seven days of age. Newborns were divided into severe or less severe hyperbilirubinemic groups (peak bilirubin ≥17 mg/dL or not. The sensitivity, specificity, and negative predictive values were determined. RESULTS: There were 158 neonates enrolled. The incidence of neonatal hyperbilirubinemia was 30.5% for a concentration ≥15 mg/dl. The rising patterns were similar among bilirubin concentrations and hydrogen peroxide levels during the first few days of life. There was a strong positive correlation between bilirubin concentrations and hydrogen peroxide levels after correlation analysis. The rate of severe hyperbilirubinemia was 13.3%. It revealed that a cord blood hydrogen peroxide signal level of 2500 counts/10 seconds was an appropriate cut-off for predicting severe hyperbilirubinemia. Sensitivity and the negative predictive value were 76.2% and 93.3%, respectively. CONCLUSIONS: Our findings confirm that hydrogen peroxide levels and bilirubin concentrations in cord and neonatal blood are closely related. A cord blood hydrogen peroxide level above 2500 counts/10 seconds associated with a high predictive value for severe hyperbilirubinemia. This method provides information about which neonate should be closely followed after discharge from the nursery.

  10. The protective effect of Aloysia triphylla aqueous extracts against brain lipid-peroxidation.

    Science.gov (United States)

    Lasagni Vitar, Romina M; Reides, Claudia G; Ferreira, Sandra M; Llesuy, Susana F

    2014-03-01

    In a normal diet, the use of herbs may contribute significantly to the total intake of plant antioxidants and even be a better source of dietary antioxidants than many other food groups. Therefore, the aims of this study were to evaluate the protective effect of aqueous extracts of Aloysia triphylla (infusion and decoction) against lipid-peroxidation of brain homogenates and to determine changes in the prooxidant/antioxidant balance when the plant material is added. In order to elucidate a possible antioxidant mechanism in vitro evaluation of total antioxidant capacity, oxygen species scavenging ability and reducing power (RP) were studied. Tested extracts had shown a strong inhibition of lipid-peroxidation measured as thiobarbituric acid-reactive products of lipid-peroxidation (TBARS) and chemiluminescence. Furthermore, infusion and decoction exhibited free radical trapping ability, expressed by the capacity to scavenge superoxide and hydrogen peroxide. Additionally, both aqueous extracts presented antioxidant activity measured as total reactive antioxidant potential (TRAP), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid radical (ABTS) scavenging activity and RP. These results suggest that the lipid-peroxidation inhibition mechanism proposed is that the antioxidants present in Aloysia triphylla could act as strong scavengers of reactive oxygen species not only at the initiation of the lipid-peroxidation chain reaction, but also at the propagation step. Therefore, they could be used as prophylactic and therapeutic agents for those diseases where the occurrence of oxidative stress and lipid-peroxidation contributes to the progression of damage.

  11. Hydrogen peroxide sensing, signaling and regulation of transcription factors

    Directory of Open Access Journals (Sweden)

    H. Susana Marinho

    2014-01-01

    Full Text Available The regulatory mechanisms by which hydrogen peroxide (H2O2 modulates the activity of transcription factors in bacteria (OxyR and PerR, lower eukaryotes (Yap1, Maf1, Hsf1 and Msn2/4 and mammalian cells (AP-1, NRF2, CREB, HSF1, HIF-1, TP53, NF-κB, NOTCH, SP1 and SCREB-1 are reviewed. The complexity of regulatory networks increases throughout the phylogenetic tree, reaching a high level of complexity in mammalians. Multiple H2O2 sensors and pathways are triggered converging in the regulation of transcription factors at several levels: (1 synthesis of the transcription factor by upregulating transcription or increasing both mRNA stability and translation; (ii stability of the transcription factor by decreasing its association with the ubiquitin E3 ligase complex or by inhibiting this complex; (iii cytoplasm–nuclear traffic by exposing/masking nuclear localization signals, or by releasing the transcription factor from partners or from membrane anchors; and (iv DNA binding and nuclear transactivation by modulating transcription factor affinity towards DNA, co-activators or repressors, and by targeting specific regions of chromatin to activate individual genes. We also discuss how H2O2 biological specificity results from diverse thiol protein sensors, with different reactivity of their sulfhydryl groups towards H2O2, being activated by different concentrations and times of exposure to H2O2. The specific regulation of local H2O2 concentrations is also crucial and results from H2O2 localized production and removal controlled by signals. Finally, we formulate equations to extract from typical experiments quantitative data concerning H2O2 reactivity with sensor molecules. Rate constants of 140 M−1 s−1 and ≥1.3 × 103 M−1 s−1 were estimated, respectively, for the reaction of H2O2 with KEAP1 and with an unknown target that mediates NRF2 protein synthesis. In conclusion, the multitude of H2O2 targets and mechanisms provides an opportunity for

  12. Mistletoe alkali inhibits peroxidation in rat liver and kidney

    Institute of Scientific and Technical Information of China (English)

    Zheng-Ming Shi; Ping Feng; Dong-Qiao Jiang; Xue-Jiang Wang

    2006-01-01

    AIM: To explore the antioxidant and free radical scavenger properties of mistletoe alkali (MA).METHODS: The antioxidant effect of mistletoe alkali on the oxidative stress induced by carbon tetrachloride (CCl4) in rats was investigated. The rats were divided into four groups (n = 8): CCl4-treated group (1 mL/kg body weight), MA -treated group (90 mg/kg), CCl4+MA-treated group and normal control group. After 4 wk of treatment,the level of malondialdehyde (MDA), a lipid peroxidation product (LPO) was measured in serum and homogenates of liver and kidney. Also, the level of glutathione (GSH),and activities of glutathione reductase (GR), glutathione peroxidase (GSPx), superoxide dismutase (SOD), and glutathione-S-transferase (GST) in liver and kidney were determined. Scavenging effects on hydroxyl free radicals produced in vitro by Fenton reaction were studied by ESR methods using 5,5-dimethyl-1-pyrroline-N-oxidesource. Urinary 8-hydroxydeoxyguanosine (8-OHdG) was determined by competitive ELISA.RESULTS: In CCl4-treated group, the level of LPO in serum of liver and kidney was significantly increased compared to controls. The levels of GSH and enzyme activities of SOD, GSPx and GR in liver and kidney were significantly decreased in comparison with controls. In CCl4+MA-treated group, the changes in the levels of LPO in serum of liver and kidney were not statistically significant compared to controls. The levels of SOD, GSPx and GR in liver and kidney were significantly increased in comparison with controls. There was a significant difference in urinary excretion of 8-OHdG between the CCl4-treated and MA-treated groups.CONCLUSION: Oxidative stress may be a major mechanism for the toxicity of CCl4. MA has a protective www.wjgnet.comeffect against CCl4 toxicity by inhibiting the oxidative damage and stimulating GST activities. Thus, clinical application of MA should be considered in cases with carbon tetrachloride-induced injury.

  13. Lipid peroxidation and cytotoxicity induced by respirable volcanic ash

    Energy Technology Data Exchange (ETDEWEB)

    Cervini-Silva, Javiera, E-mail: jcervini@correo.cua.uam.mx [Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana Unidad Cuajimalpa, México City (Mexico); Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Nieto-Camacho, Antonio [Laboratorio de Pruebas Biológicas, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México City (Mexico); Gomez-Vidales, Virginia [Laboratorio de Resonancia Paramagnética Electrónica, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México City (Mexico); Ramirez-Apan, María Teresa [Laboratorio de Pruebas Biológicas, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, México City (Mexico); Palacios, Eduardo; Montoya, Ascención [Dirección de Investigación y Posgrado, Instituto Mexicano del Petróleo (Mexico); Kaufhold, Stephan [BGR Bundesansaltfür Geowissenschaften und Rohstoffe, Stilleweg 2, D-30655 Hannover (Germany); and others

    2014-06-01

    Highlights: • Respirable volcanic ash induces oxidative degradation of lipids in cell membranes. • Respirable volcanic ash triggers cytotoxicity in murin monocyle/macrophage cells. • Oxidative stress is surface controlled but not restricted by surface- Fe{sup 3+}. • Surface Fe{sup 3+} acts as a stronger inductor in allophanes vs phyllosilicates or oxides. • Registered cell-viability values were as low as 68.5 ± 6.7%. - Abstract: This paper reports that the main component of respirable volcanic ash, allophane, induces lipid peroxidation (LP), the oxidative degradation of lipids in cell membranes, and cytotoxicity in murin monocyle/macrophage cells. Naturally-occurring allophane collected from New Zealand, Japan, and Ecuador was studied. The quantification of LP was conducted using the Thiobarbituric Acid Reactive Substances (TBARS) assay. The cytotoxic effect was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide colorimetric assay. Electron-Paramagnetic Resonance (EPR) determinations of naturally-occurring allophane confirmed the incorporation in the structure and clustering of structural Fe{sup 3+}, and nucleation and growth of small-sized Fe (oxyhydr)oxide or gibbsite. LP induced by allophane varied with time, and solid concentration and composition, reaching 6.7 ± 0.2 nmol TBARS mg prot{sup −1}. LP was surface controlled but not restricted by structural or surface-bound Fe{sup 3+}, because redox processes induced by soluble components other than perferryl iron. The reactivity of Fe{sup 3+} soluble species stemming from surface-bound Fe{sup 3+} or small-sized Fe{sup 3+} refractory minerals in allophane surpassed that of structural Fe{sup 3+} located in tetrahedral or octahedral sites of phyllosilicates or bulk iron oxides. Desferrioxamine B mesylate salt (DFOB) or ethylenediaminetetraacetic acid (EDTA) inhibited LP. EDTA acted as a more effective inhibitor, explained by multiple electron transfer pathways. Registered cell

  14. Observation of atmospheric peroxides during Wangdu Campaign 2014 at a rural site in the North China Plain

    Science.gov (United States)

    Wang, Yin; Chen, Zhongming; Wu, Qinqin; Liang, Hao; Huang, Liubin; Li, Huan; Lu, Keding; Wu, Yusheng; Dong, Huabin; Zeng, Limin; Zhang, Yuanhang

    2016-09-01

    Measurements of atmospheric peroxides were made during Wangdu Campaign 2014 at Wangdu, a rural site in the North China Plain (NCP) in summer 2014. The predominant peroxides were detected to be hydrogen peroxide (H2O2), methyl hydroperoxide (MHP) and peroxyacetic acid (PAA). The observed H2O2 reached up to 11.3 ppbv, which was the highest value compared with previous observations in China at summer time. A box model simulation based on the Master Chemical Mechanism and constrained by the simultaneous observations of physical parameters and chemical species was performed to explore the chemical budget of atmospheric peroxides. Photochemical oxidation of alkenes was found to be the major secondary formation pathway of atmospheric peroxides, while contributions from alkanes and aromatics were of minor importance. The comparison of modeled and measured peroxide concentrations revealed an underestimation during biomass burning events and an overestimation on haze days, which were ascribed to the direct production of peroxides from biomass burning and the heterogeneous uptake of peroxides by aerosols, respectively. The strengths of the primary emissions from biomass burning were on the same order of the known secondary production rates of atmospheric peroxides during the biomass burning events. The heterogeneous process on aerosol particles was suggested to be the predominant sink for atmospheric peroxides. The atmospheric lifetime of peroxides on haze days in summer in the NCP was about 2-3 h, which is in good agreement with the laboratory studies. Further comprehensive investigations are necessary to better understand the impact of biomass burning and heterogeneous uptake on the concentration of peroxides in the atmosphere.

  15. Evaluation of the biological efficacy of hydrogen peroxide vapour decontamination in wards of an Australian hospital.

    Science.gov (United States)

    Chan, H-T; White, P; Sheorey, H; Cocks, J; Waters, M-J

    2011-10-01

    This study assessed the efficacy of a 'dry' hydrogen peroxide vapour decontamination in an Australian hospital via a two-armed study. The in vivo arm examined the baseline bacterial counts in high-touch zones within wards and evaluated the efficacy of cleaning with a neutral detergent followed by either hydrogen peroxide vapour decontamination, or a manual terminal clean with bleach or Det-Sol 500. The in vitro arm examined the efficacy of hydrogen peroxide vapour decontamination on a variety of different surfaces commonly found in the wards of an Australian hospital, deliberately seeded with a known concentration of vancomycin-resistant enterococci (VRE). All bacterial counts were evaluated by a protocol of contact plate method. In the in vivo arm, 33.3% of the high-touch areas assessed had aerobic bacterial count below the detection limit (i.e. no bacteria recoverable) post hydrogen peroxide decontamination, and in all circumstances the highest microbial density was ≤3 cfu/cm(2), while in the in vitro arm there was at least a reduction in bacterial load by a factor of 10 at all surfaces investigated. These results showed that dry hydrogen peroxide vapour room decontamination is highly effective on a range of surfaces, although the cleanliness data obtained by these methods cannot be easily compared among the different surfaces as recovery of organisms is affected by the nature of the surface.

  16. Role of mitochondrial dysfunction in hydrogen peroxide-induced apoptosis of intestinal epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Jian-Ming Li; Hong Zhou; Qian Cai; Guang-Xia Xiao

    2003-01-01

    AIM: To study the role of mitochondrial dysfunction in hydrogen peroxide-induced apoptosis of intestinal epithelial cells.METHODS: Hydrogen peroxide-induced apoptosis of human intestinal epithelial cell line SW-480 was established. Cell apoptosis was determined by Annexin-V and PI doublestained flow cytometry and DNA gel electrophoresis.Morphological changes were examined with light and electron microscopy. For other observations, mitochondrial function,cytochrome c release, mitochondrial translocation and membrane potential were determined simultaneously.RESULTS: Percentage of apoptotic cells induced with 400μ mol/L hydrogen peroxide increased significantly at I h or 3h after stimulation and recovered rapidly. Meanwhile percentage of apoptotic cells induced with 4 mmol/L hydrogen peroxide increased with time. In accordance with these changes, we observed decreased mitochondrial function in 400 μmol/L H2O2-stimualted cells at 1 h or 3 h and in 4 mmol/L H2O2-stimualted cells at times examined.Correspondingly, swelling cristae and vacuole-like mitochondria were noted. Release of cytochrome c,decreased mitochondrial membrane potential and mitochondrial translocation were also found to be the early signs of apoptosis.CONCLUSION: Dysfunctional mitochondria play a role in the apoptosis of SW-480 cell line induced by hydrogen peroxide.

  17. Preparation of Barium Titanate Nanopowder through Thermal Decomposition of Peroxide Precursor and Its Formation Mechanism

    Institute of Scientific and Technical Information of China (English)

    PENG, Yangxi; CHEN, Qiyuan; LIU, Shijun

    2009-01-01

    H_2TiO_3 was dissolved in the mixture of hydrogen formed peroxide and ammonia under the pH range of 8-10 with a transparent yellow solution formed. When an equivalent mole of Ba~(2+) solution was added into the yellow solution, the precipitate produced was the peroxide precursor of barium titanate. The cubic nanopowder of barium titanate was obtained when the precipitate was washed, stoved, and then calcined at 600 ℃ for 1 h. The peroxide precursor of barium titanate and barium titanate nanopowder prepared were characterized to be BaTi(H_2O_2)_2O_3 by TGA-DTA, XRD, TEM, SEM, and XREDS. The peroxide precursor of barium titanate was determined to be BaTi(H_2O_2)_2O_3. The particle size of the barium titanate nanopowder, the calcined product of BaTi(H_2O_2)_2O_3, was in the range of 20-40 nm. A formation mechanism of the barium titanate nanopowder through thermal decomposition of its peroxide precursor was proposed and then validated.

  18. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Science.gov (United States)

    Semsang, Nuananong; Yu, LiangDeng

    2013-07-01

    Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  19. Prediction of the thermal decomposition of organic peroxides by validated QSPR models

    Energy Technology Data Exchange (ETDEWEB)

    Prana, Vinca [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Rotureau, Patricia, E-mail: patricia.rotureau@ineris.fr [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Fayet, Guillaume [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); André, David; Hub, Serge [ARKEMA, rue Henri Moissan, BP63, Pierre Benite 69493 (France); Vicot, Patricia [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Rao, Li [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Adamo, Carlo [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Institut Universitaire de France, 103 Boulevard Saint Michel, Paris F-75005 (France)

    2014-07-15

    Highlights: • QSPR models were developed for thermal stability of organic peroxides. • Two accurate MLR models were exhibited based on quantum chemical descriptors. • Performances were evaluated by a series of internal and external validations. • The new QSPR models satisfied all OCDE principles of validation for regulatory use. - Abstract: Organic peroxides are unstable chemicals which can easily decompose and may lead to explosion. Such a process can be characterized by physico-chemical parameters such as heat and temperature of decomposition, whose determination is crucial to manage related hazards. These thermal stability properties are also required within many regulatory frameworks related to chemicals in order to assess their hazardous properties. In this work, new quantitative structure–property relationships (QSPR) models were developed to predict accurately the thermal stability of organic peroxides from their molecular structure respecting the OECD guidelines for regulatory acceptability of QSPRs. Based on the acquisition of 38 reference experimental data using DSC (differential scanning calorimetry) apparatus in homogenous experimental conditions, multi-linear models were derived for the prediction of the decomposition heat and the onset temperature using different types of molecular descriptors. Models were tested by internal and external validation tests and their applicability domains were defined and analyzed. Being rigorously validated, they presented the best performances in terms of fitting, robustness and predictive power and the descriptors used in these models were linked to the peroxide bond whose breaking represents the main decomposition mechanism of organic peroxides.

  20. Hydrogen peroxide and polyamines act as double edged swords in plant abiotic stress responses

    Directory of Open Access Journals (Sweden)

    Kamala Gupta

    2016-09-01

    Full Text Available The specific genetic changes through which plants adapt to the multitude of environmental stresses are possible because of the molecular regulations in the system. These intricate regulatory mechanisms once unveiled will surely raise interesting questions. Polyamines and hydrogen peroxide have been suggested to be important signalling molecules during biotic and abiotic stresses. Hydrogen peroxide plays a versatile role from orchestrating physiological processes to stress response. It helps to achieve acclimatization and tolerance to stress by coordinating intra-cellular and systemic signalling systems. Polyamines, on the other hand, are low molecular weight polycationic aliphatic amines, which have been implicated in various stress responses. It is quite interesting to note that both hydrogen peroxide and polyamines have a fine line of inter-relation between them since the catabolic pathways of the latter releases hydrogen peroxide. In this review we have tried to illustrate the roles and their multifaceted functions of these two important signalling molecules based on current literature. This review also highlights the fact that over accumulation of hydrogen peroxide and polyamines can be detrimental for plant cells leading to toxicity and pre-mature cell death.