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Sample records for benzoyl peroxide

  1. A Three-Step Acne System Containing Solubilized Benzoyl Peroxide versus Benzoyl Peroxide/Clindamycin in Pediatric Patients with Acne

    OpenAIRE

    Eichenfield, Lawrence F.; Thiboutot, Diane; Shalita, Alan; Swinyer, Leonard; Tanghetti, Emil; Tschen, Eduardo; Parr, Lisa

    2009-01-01

    Objective. To evaluate the clinical benefit in adolescents of a three-step acne system containing solubilized benzoyl peroxide. Design. Patients in this multicenter, investigator-blind trial were randomly assigned to receive 10 weeks of treatment with either the three-step acne system for normal-to-oily skin (proprietary 2% salicylic acid cleanser twice daily + proprietary 2% salicylic acid toner once daily + solubilized 5% benzoyl peroxide gel twice daily) or with control cleanser + 5% benzo...

  2. Preparation and Physicochemical Evaluation of Benzoyl Peroxide 5% Foamable Emu oil Emulsion

    OpenAIRE

    Shatalebi; Roostaei

    2015-01-01

    Background Acne vulgaris is the most common skin disorder, characterized by the inflammation of the pilosebaceous glands. In addition to physical disfigurement, acne vulgaris may be responsible for significant emotional and physiological distress. Many medications involve in prevention and treatment of acne. Benzoyl peroxide could be a potent candidate with special formulation to treat acne. Objectives Benzoyl peroxide foamable em...

  3. 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.…

  4. The Tolerability Profile of Clindamycin 1%/Benzoyl Peroxide 5% Gel vs. Adapalene 0.1%/Benzoyl Peroxide 2.5% Gel for Facial Acne: Results of Two Randomized, Single-Blind, Split-Face Studies

    OpenAIRE

    Green, Lawrence; Cirigliano, Marcela; Gwazdauskas, Jennifer A; Gonzalez, Pablo

    2012-01-01

    Objective: To compare the first two weeks of tolerability of clindamycin/benzoyl peroxide gel versus adapalene/benzoyl peroxide gel followed by six weeks of open-label clindamycin/benzoyl peroxide gel therapy in subjects with mild-to-moderate acne who participated in two eight-week, identically designed, clinical studies. Methods: Using a split-face method, patients received both clindamycin/benzoyl peroxide gel and adapalene/benzoyl peroxide gel once daily for two weeks (allocation to the ri...

  5. Rapid detection of benzoyl peroxide in wheat flour by using Raman scattering spectroscopy

    Science.gov (United States)

    Zhao, Juan; Peng, Yankun; Chao, Kuanglin; Qin, Jianwei; Dhakal, Sagar; Xu, Tianfeng

    2015-05-01

    Benzoyl peroxide is a common flour additive that improves the whiteness of flour and the storage properties of flour products. However, benzoyl peroxide adversely affects the nutritional content of flour, and excess consumption causes nausea, dizziness, other poisoning, and serious liver damage. This study was focus on detection of the benzoyl peroxide added in wheat flour. A Raman scattering spectroscopy system was used to acquire spectral signal from sample data and identify benzoyl peroxide based on Raman spectral peak position. The optical devices consisted of Raman spectrometer and CCD camera, 785 nm laser module, optical fiber, prober, and a translation stage to develop a real-time, nondestructive detection system. Pure flour, pure benzoyl peroxide and different concentrations of benzoyl peroxide mixed with flour were prepared as three sets samples to measure the Raman spectrum. These samples were placed in the same type of petri dish to maintain a fixed distance between the Raman CCD and petri dish during spectral collection. The mixed samples were worked by pretreatment of homogenization and collected multiple sets of data of each mixture. The exposure time of this experiment was set at 0.5s. The Savitzky Golay (S-G) algorithm and polynomial curve-fitting method was applied to remove the fluorescence background from the Raman spectrum. The Raman spectral peaks at 619 cm-1, 848 cm-1, 890 cm-1, 1001 cm-1, 1234 cm-1, 1603cm-1, 1777cm-1 were identified as the Raman fingerprint of benzoyl peroxide. Based on the relationship between the Raman intensity of the most prominent peak at around 1001 cm-1 and log values of benzoyl peroxide concentrations, the chemical concentration prediction model was developed. This research demonstrated that Raman detection system could effectively and rapidly identify benzoyl peroxide adulteration in wheat flour. The experimental result is promising and the system with further modification can be applicable for more products in near

  6. A 6% Benzoyl Peroxide Foaming Cloth Cleanser Used in the Treatment of Acne Vulgaris: Aesthetic Characteristics, Patient Preference Considerations, and Impact on Compliance with Treatment

    OpenAIRE

    Del Rosso, James Q.

    2009-01-01

    Objective: The study was conducted to evaluate the product attributes of a new benzoyl peroxide-containing foaming cloth cleanser and to compare the overall patient satisfaction of this product with two currently available benzoyl peroxide acne products (6% benzoyl peroxide cleanser and 4% benzoyl peroxide wash). Design: This was a randomized, single-blind study. Setting: Two clinical trial sites. Participants: Male and female subjects (N=193) aged 17 to 30 years with a history of acne vulgar...

  7. Investigation of the decomposition reaction and dust explosion characteristics of crystalline benzoyl peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Lu, K.-T. [Department of Applied Chemistry and Materials Science, Chung Cheng Institute of Technology, National Defense University, Taoyuan 33509, Taiwan (China)], E-mail: ktlu@ndu.edu.tw; Chen, T.-C. [Department of Applied Chemistry and Materials Science, Chung Cheng Institute of Technology, National Defense University, Taoyuan 33509, Taiwan (China); Hu, K.-H. [Department of Occupational Safety and Health, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli, Taiwan (China)

    2009-01-15

    The benzoyl peroxide (BPO) is widely used in the chemical industry. Many catastrophes have been caused by its thermal instability or reactive incompatibility in storage or thermal decomposition reaction. Thus, its hazard characteristics have to be clearly identified. First of all, the differential scanning calorimeter (DSC) is used to measure the heat of decomposition reaction, which can contribute to understanding the reaction characteristics of benzoyl peroxide. The accelerating rate calorimeter (ARC) is used to measure the rates of temperature and pressure rises of decomposition reaction, and then the kinetics parameters are estimated. Furthermore, the MIKE 3 apparatus and the 20-l-Apparatus are used to measure and analyze the dust explosion characteristics of benzoyl peroxide under room temperature and atmospheric pressure. Finally, Semenov's thermal explosion theory is applied to investigate the critical runaway condition and the stability criterion of decomposition reaction, and to build the relationship of critical temperature, convective heat transfer coefficient, heat transfer surface area and ambient temperature. These results contribute to improving the safety in the reaction, transportation and storage processes of benzoyl peroxide.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Profile of clindamycin phosphate 1.2%/benzoyl peroxide 3.75% aqueous gel for the treatment of acne vulgaris

    Directory of Open Access Journals (Sweden)

    Nguyen TA

    2015-10-01

    Full Text Available Tuyet A Nguyen,1,2 Lawrence F Eichenfield1,31Division of Pediatric and Adolescent Dermatology, Rady Children's Hospital, San Diego, CA, 2Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 3Department of Dermatology, University of California, San Diego, La Jolla, CA, USA Abstract: Acne vulgaris is a common and chronic skin disease, and is a frequent source of morbidity for affected patients. Treatment of acne vulgaris is often difficult due to the multifactorial nature of this disease. Combination therapy, such as that containing clindamycin and benzoyl peroxide, has become the standard of care. Several fixed formulations of clindamycin 1% and benzoyl peroxide of varying concentrations are available and have been used with considerable success. The major limitation is irritation and dryness from higher concentrations of benzoyl peroxide, and a combination providing optimal efficacy and tolerability has yet to be determined. Recently, a clindamycin and benzoyl peroxide 3.75% fixed combination formulation was developed. Studies have suggested that this formulation may be a safe and effective treatment regimen for patients with acne vulgaris. Here, we provide a brief review of acne pathogenesis, benzoyl peroxide and clindamycin, and profile a new Clindamycin-BP 3.75% fixed combination gel for the treatment of moderate-to-severe acne vulgaris. Keywords: acne vulgaris, benzoyl peroxide, clindamycin

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

    International Nuclear Information System (INIS)

    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

  11. Efficacy and Tolerability of a Three-Step Acne System Containing a Solubilized Benzoyl Peroxide Lotion versus a Benzoyl Peroxide/Clindamycin Combination Product: An Investigator-Blind, Randomized, Parallel-Group Study

    OpenAIRE

    Green, Lawrence J.; Del Rosso, James Q.

    2008-01-01

    A brand three-step acne treatment system containing a solubilized 5% benzoyl lotion and a designated cleanser and moisturizer was compared with a brand benzoyl peroxide 5%/clindamycin 1% gel in subjects with acne vulgaris. The single-center, four-week study was investigator-blinded and randomized. The three-step acne treatment system proved to be comparable in efficacy and tolerability.

  12. 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...

  13. Benzoyl peroxide increases UVA-induced plasma membrane damage and lipid oxidation in murine leukemia L1210 cells.

    Science.gov (United States)

    Ibbotson, S H; Lambert, C R; Moran, M N; Lynch, M C; Kochevar, I E

    1998-01-01

    Ultraviolet A radiation induces oxidative stress and cell damage. The purpose of this investigation was to examine whether ultraviolet A-induced cell injury was amplified by the presence of a non-ultraviolet A absorbing molecule capable of generating free radicals. Benzoyl peroxide was used as a lipid soluble potential radical-generating agent. Plasma membrane permeability assessed by trypan blue uptake was used to measure cell damage in murine leukemia L1210 cells. Cells were irradiated with a pulsed Nd/YAG laser at 355 nm using 0-160 J per cm2. The ratio of the fluence-response slope in the presence of 40 microM benzoyl peroxide to that of irradiated controls was 4.3 +/- 2.6. Benzoyl peroxide alone or benzoyl peroxide added after irradiation did not cause increased trypan blue uptake. The ratio of the fluence-response slopes in the presence of 40 microM benzoyl peroxide to that of irradiated controls was 4.7 +/- 1.4 when cells were irradiated (0-43 J per cm2) with a xenon lamp, filtered to remove wavelengths butylated hydroxytoluene, vitamin E, and trolox, a water-soluble vitamin E derivative. Lipid oxidation, assessed as thiobarbituric acid reactive substances, was significantly increased in samples irradiated with ultraviolet A in the presence of benzoyl peroxide at fluences >34 J per cm2. The increased trypan blue uptake and thiobarbituric acid reactive substances were inhibited by butylated hydroxytoluene. These results suggest that agents not absorbing ultraviolet A radiation may enhance ultraviolet A-initiated oxidative stress in cells. PMID:9424093

  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. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. 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. PMID:27434156

  18. 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.

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

    International Nuclear Information System (INIS)

    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: ► Benzoyl peroxide can oxidize Fe2+ into Fe3+. ► Fe3+ selectively induces the opening of rhodamine spirolactam ring. ► The two reactions led to the development of a new fluorescent method for benzoyl peroxide. ► 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 Fe2+ into Fe3+ and the resulting Fe3+ 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−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.

  20. Randomized, Observer-blind, Split-face Compatibility Study with Clindamycin Phosphate 1.2%/Benzoyl Peroxide 3.75% gel and Facial Foundation Makeup

    Science.gov (United States)

    Pillai, Radhakrishnan

    2015-01-01

    Background: Cosmetic compatibility in the treatment of acne is an important issue significantly impacting quality of life, but often overlooked, as dermatologists commonly recommended avoidance of cosmetic foundations when treating adult female patients. Fixed combinations of clindamycin/benzoyl peroxide are widely used in the treatment of acne, but little is known about the impact of their concomitant use with facial foundation. Objective: To assess the compatibility of clindamycin phosphate 1. 2%/benzoyl peroxide 3. 75% gel with foundation makeup for up to six hours after application. Methods: Twenty-nine female subjects applied makeup to their face after randomly applying clindamycin phosphate 1. 2%/benzoyl peroxide 3. 75% gel to one side of the face. Investigator and subject self- assessment included facial skin attributes, facial tolerability, and cosmetic compatibility post-application and at Hour 6; as well as cutaneous tolerability. Results: No statistical difference was noted between the treated and untreated side of the face in terms of coverage, blotchiness, appearance, skin tone, or visual smoothness. Tolerability was excellent, with no erythema, edema, dryness, and peeling post-makeup application. For both the treated and untreated side, there was a slight lack of improvement in cosmetic appearance six hours post-makeup application. Conclusion: Clindamycin/benzoyl peroxide 3. 75% gel was shown to have excellent cosmetic compatibility with facial foundation. PMID:26430488

  1. 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

  2. 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.

  3. 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.

  4. 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...

  5. Topical therapy for acne in women: is there a role for clindamycin phosphate-benzoyl peroxide gel?

    Science.gov (United States)

    Del Rosso, James Q

    2014-10-01

    Acne vulgaris (AV) in adult women is commonly encountered in clinical dermatology practice. This patient subset often experiences psychosocial effects that differ in some ways from those experienced by adolescent females with AV, as they were not expecting to have to deal with this disorder beyond their adolescent years. Most of the emphasis on therapy for adult women with AV has focused on use of oral contraceptives (OCs) and/or oral spironolactone, with little to no evaluation or discussion of topical agents in this patient group. This article provides an overview of AV in adult women and presents the results of a subanalysis of data from female patients who were treated in phase 3 studies with clindamycin phosphate (CP) 1.2%-benzoyl peroxide (BP) 2.5% gel once daily for facial AV. The subanalysis compared outcomes in females younger than 25 years and in those 25 years and older. Overall, the data showed that therapeutic outcomes were comparable between the 2 groups. PMID:25372252

  6. 光度法测定小麦粉中过氧化苯甲酰研究%Spectrophotometric Determination of Flour Benzoyl Peroxide

    Institute of Scientific and Technical Information of China (English)

    田林双; 于伟; 吴存兵; 顾鹏程; 周琳琨; 邱琳

    2013-01-01

    基于过氧化苯甲酰的氧化性,将Fe2+氧化成Fe3+,生成的Fe3+与硫氰酸盐在酸性乙醇介质中发生显色反应,建立小麦粉违禁添加剂过氧化苯甲酰检测新方法.对该方法进行试验条件研究,包括光谱吸收曲线、反应介质、酸含量、反应温度、反应时间、Fe2浓度、KSCN浓度、共存干扰物质等因素对检测结果的影响.最佳试验条件下,过氧化苯甲酰线性范围0.1~15 mg/L,相关系数R2=0.999 4,505 nm处表观摩尔吸光系数ε =2.136 5×104 L·mol-1·cm-1,检出限0.025 mg/L.利用该方法对市售小麦粉样品进行测定,回收率在97.2%~104.4%之间.%A new method for benzoyl peroxide detection was proposed.It was based on the principle that benzoyl peroxide oxidize ferrous iron to ferric ion,then color reaction between ferric ion and thiocyanate in ethanol and acid system can be quantified.Experimental conditions of the benzoyl peroxide detection method including absorption curve,reaction medium,acid content,reaction temperature,reaction time,ferrous iron content,thiocyanate content and interfering substances were studied in the research.Under the optimum conditions,the linear range of benzoyl peroxide concentration was 0.1 ~ 15 mg/L,with a correlation coefficient (R2) of 0.999 4 and a lower detection limit of 0.025 mg/L.The apparent molar adsorptivity of the coordination complex was 2.136 5 × 104 L · mol-1 · cm-1The recovery was at the range of 97.2% to 104.4% by this method to detect commercial flour samples.

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

    Directory of Open Access Journals (Sweden)

    Gupta A

    2014-12-01

    Full Text Available Ankush Gupta,1,* Sima Singh,1,* Niranjan G Kotla,1 Thomas J Webster2,3 1Department of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab, India; 2Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 3Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia *These authors contributed equally to this work Abstract: 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/cm2 and 5.04±0.014 µg/cm2, 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

  8. Sub-group Analyses from a Trial of a Fixed Combination of Clindamycin Phosphate 1.2% and Benzoyl Peroxide 3.75% Gel for the Treatment of Moderate-to-severe Acne Vulgaris

    Science.gov (United States)

    Korotzer, Andrew

    2015-01-01

    Background: Acne vulgaris is commonplace and can be difficult to manage. Providing an effective and well-tolerated treatment may lead to improved adherence, increased patient satisfaction, and improved clinical outcomes. Methods: A review of efficacy, safety, and cutaneous tolerability of clindamycin phosphate 1.2%-benzoyl peroxide 3.75% gel in 498 patients with moderate-to-severe acne vulgaris enrolled in a multicenter Phase III study randomized to receive active or vehicle once daily for 12 weeks, including the most recent post-hoc analyses. Results: Significantly superior reductions in lesion counts were observed with clindamycin phosphate 1.2%-benzoyl peroxide 3.75% gel from Week 4, with median percent reductions in inflammatory and noninflammatory lesions from baseline of 68.4 and 57.9 percent, respectively (bothp<0.001 versus vehicle). More than half (55.1%) of the severe acne vulgaris patients treated with clindamycin phosphate 1.2%-benzoyl peroxide 3.75% gel achieved ≥2-grade improvement from baseline in their Evaluator’s Global Severity Score, and almost a third of the adolescent acne vulgaris patients (32.4%) achieved at least a marked improvement in their acne vulgaris as early as Week 2. In adult female acne overall treatments success was achieved in 52.7 percent of patients treated with clindamycin phosphate 1.2%-benzoyl peroxide 3.75% gel. Overall, and in the specific subpopulations, clindamycin phosphate 1.2%-benzoyl peroxide 3.75% gel was well-tolerated with a similar adverse event profile to vehicle. Limitations: Post-hoc analyses from a single clinical trial with demographic imbalances that could potentially confound the results. Conclusion: Clindamycin phosphate 1.2%-benzoyl peroxide 3.75% gel appears to be effective in treating acne across various clinically relevant sub-groups. PMID:26705445

  9. The isolated perfused bovine udder as an in vitro model of percutaneous drug absorption. Skin viability and percutaneous absorption of dexamethasone, benzoyl peroxide, and etofenamate.

    Science.gov (United States)

    Kietzmann, M; Löscher, W; Arens, D; Maass, P; Lubach, D

    1993-10-01

    Using udders from slaughtered cows as a new in vitro model of percutaneous drug absorption, the tissue viability and the percutaneous absorption of dexamethasone, benzoyl peroxide, and etofenamate were studied. The organ was perfused with gassed tyrode solution for up to 6 hr. As shown by measurement of glucose consumption, lactate production, lactate dehydrogenase activity, and pH in the perfusate, the tissue was viable over a 6-hr period. This was confirmed by a histological examination. Determination of the udder skin-fold thickness demonstrated that no edema developed within the perfusion period. A maximum skin penetration of dexamethasone was found after administration of dexamethasone dissolved in acetone with dimethyl sulfoxide, followed by ointment with salicylic acid, ointment without salicylic acid, and acetone solution. Experiments with benzoyl peroxide and etofenamate demonstrated that the perfused udder skin was capable of metabolizing drugs in vitro. In conclusion, the isolated perfused bovine udder is a new in vitro model, which maintains bovine udder skin with an isolated vasculature in a viable state. Using this in vitro model, we note it is possible to compare the dermal penetration, metabolism, and absorption of substances after topical administration of different drug formulations. PMID:8298184

  10. Benzoyl Peroxide Topical

    Science.gov (United States)

    ... cosmetics or soaps that dry the skin, medicated cosmetics, sunlight, and sunlamps) unless directed otherwise by your doctor.It may take 4 to 6 weeks to see the effects of this medication. If your acne does not ...

  11. 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.

  12. Multicenter study for efficacy and safety evaluation of a fixeddose combination gel with adapalen 0.1% and benzoyl peroxide 2.5% (Epiduo® for the treatment of acne vulgaris in Brazilian population*

    Science.gov (United States)

    Sittart, José Alexandre de Souza; da Costa, Adilson; Mulinari-Brenner, Fabiane; Follador, Ivonise; Azulay-Abulafia, Luna; de Castro, Lia Cândida Miranda

    2015-01-01

    BACKGROUND The current options for the treatment of acne vulgaris present many mechanisms of action. For several times, dermatologists try topical agents combinations, looking for better results. OBJECTIVES To evaluate the efficacy, tolerability and safety of a topical, fixed-dose combination of adapalene 0.1% and benzoyl peroxide 2.5% gel for the treatment of acne vulgaris in the Brazilian population. METHODS This is a multicenter, open-label and interventionist study. Patients applied 1.0 g of the fixed-dose combination of adapalene 0.1% and benzoyl peroxide 2.5% gel on the face, once daily at bedtime, during 12 weeks. Lesions were counted in all of the appointments, and the degree of acne severity, overall improvement, tolerability and safety were evaluated in each visit. RESULTS From 79 recruited patients, 73 concluded the study. There was significant, fast and progressive reduction of non-inflammatory, inflammatory and total number of lesions. At the end of the study, 75.3% of patients had a reduction of >50% in non-inflammatory lesions, 69.9% in inflammatory lesions and 78.1% in total number of lesions. Of the 73 patients, 71.2% had good to excellent response and 87.6% had satisfactory to good response. In the first week of treatment, erythema, burning, scaling and dryness of the skin were frequent complaints, but, from second week on, these signals and symptoms have reduced. CONCLUSION The fixed-dose combination of adapalene 0.1% and benzoyl peroxide 2.5% gel is effective, safe, well tolerated and apparently improves patient compliance with the treatment. PMID:27168522

  13. Adapalene 0.1% and benzoyl peroxide 2.5% as a fixed-dose combination gel is as well tolerated as the individual components alone in terms of cumulative irritancy.

    Science.gov (United States)

    Loesche, Christian; Pernin, Colette; Poncet, Michel

    2008-01-01

    International guidelines recommend the combination of retinoids (e.g. adapalene, tazarotene) and benzoyl peroxide for treating acne because of their complementary mechanisms of action. A new fixed-dose combination gel of adapalene 0.1% and benzoyl peroxide (BPO) 2.5% (adapalene/BPO*) is an effective acne treatment and offers the advantage of a once daily application. This paper reports the results of a cumulative irritancy study in healthy volunteers comparing adapalene/BPO to adapalene 0.1% and BPO 2.5% applied separately, BPO 10% gel, tazarotene 0.1% gel and the gel vehicle as a control.There was no significant difference between the mean cumulative irritation index (MCII) for adapalene/BPO and any test product except tazarotene 0.1% gel, which had a significantly greater MCII than all other test products (p < 0.05). This study showed that adapalene/BPO as a fixed-dose combination is as well tolerated as BPO 2.5% gel alone or adapalene 0.1% gel alone in terms of cumulative irritancy.*Epiduo, Galderma S.A. PMID:18693154

  14. 离心沉淀气相色谱法测定面粉中过氧化苯甲酰含量的研究%Determination of Benzoyl Peroxide in Wheat Flour by Gas Chromatography after Precipitation by Centrifugation

    Institute of Scientific and Technical Information of China (English)

    应兴华; 徐霞; 朱智伟; 闵捷; 朱敏; 翟远建

    2009-01-01

    An analytical method of gas chromatography with flame ionization detection after precipitated by centrifugation was established for determination of benzoyl peroxide in wheat flour. The effects of different extraction time on the extraction efficiency and different calibration strategies for quantification were investigated, respectively. The benzoyl peroxide which was extracted from wheat flour with petroleum ether(60~90℃) was converted to benzoic acid in acidic condition, and then analyzed by gas chromatography with flame ionization detection. Recovery studies were performed at 0.06,0.18 and 0.30 g/kg fortification levels and the recoveries obtained ranging from 82.70% to 89.46% with relative standard deviations ranging from 3.77% to 6.93%. The method showed good linearity over the range assayed of 0.005~0.08 g/L and the detection limit was 2 mg/kg. The proposed method was suitable for determining benzoyl peroxide in wheat flour with high sensitivity, good accuracy and low-cost.%建立了离心沉淀,气相色谱氢火焰离子化检测器测定面粉中过氧化苯甲酰含量的方法.考察了不同提取时间和采用不同工作曲线对过氧化苯甲酰测定的影响.试样在石油醚中被冰乙酸还原成苯甲酸,经HP-5(30 m×0.25 mm×0.25 μm)毛细管气相色谱柱分离,氢火焰离子化检测器测定.方法的线性范围为0.005~0.08 g/L(r=0.9992),检出限(S/N=3)为2 mg/kg.在添标水平为0.06、0.18和0.30 g/kg时的平均回收率为82.70%~89.46%,相对标准偏差为3.77%~6.93%.该方法仪器设备简单,测定结果灵敏、准确,适合面粉中过氧化苯甲酰的测定.

  15. When do efficacy outcomes in clinical trials correlate with clinical relevance? analysis of clindamycin phosphate 1.2%-benzoyl peroxide 3.75% gel in moderate to severe acne vulgaris.

    Science.gov (United States)

    Del Rosso, James Q

    2016-07-01

    Acne vulgaris (AV) is a common skin disease that is challenging to successfully treat due to its complex underlying pathophysiology and chronicity. Unrealistic expectations based on the desire for rapid and complete clearance or local tolerability reactions related to topical medications often lead to incomplete adherence with therapy, premature treatment cessation, and poor therapeutic outcomes. Despite stressing to patients the importance of compliance and the lag time of several weeks before visible improvement may be noted with treatments for AV, data on evaluation of the time taken to achieve a clinically meaningful improvement of AV that may be perceived by clinicians and patients are limited. Clindamycin phosphate 1.2%-benzoyl peroxide 3.75% (clindamycin-BP 3.75%) gel has been shown in pivotal trials to be effective and well tolerated in patients with moderate to severe AV. This article reviews a new concept referred to as time to onset of action (TOA), which is described in detail and illustrated using the pivotal trial data with clindamycin-BP 3.75% gel for treatment of AV. PMID:27529706

  16. Adapalene-benzoyl peroxide once-daily, fixed-dose combination gel for the treatment of acne vulgaris: a randomized, bilateral (split-face), dose-assessment study of cutaneous tolerability in healthy participants.

    Science.gov (United States)

    Andres, Philippe; Pernin, Colette; Poncet, Michel

    2008-03-01

    Combination therapy is an effective approach to simultaneously target multiple pathogenic factors of acne. International consensus guidelines recommend the use of topical retinoids and benzoyl peroxide (BPO) for acne treatment. These drugs are often prescribed as a free combination without any safety concern associated with antibiotic use. A 3-week, randomized, controlled, investigator-blinded, single-center, bilateral (split-face), dose-assessment study was conducted comparing the cutaneous tolerability of 2 adapalene-BPO fixed-dose combination products versus various concentrations of BPO monotherapy applied once daily. Sixty healthy participants were randomized to one of the following treatment groups: adapalene 0.1%-BPO 2.5% combination product versus BPO 2.5% monotherapy; adapalene 0.1%-BPO 2.5% combination product versus BPO 5% monotherapy; adapalene 0.1%-BPO 5% combination product versus BPO 5% monotherapy; and adapalene 0.1%-BPO 5% combination product versus BPO 10% monotherapy. Assessments included total sum score (TSS) of irritation signs/ symptoms (erythema, scaling/desquamation, dryness, pruritus, stinging/burning) averaged over all postbaseline visits, individual irritation signs/symptoms (worst score), and adverse events. The overall cutaneous tolerability profile of the adapalene 0.1%-BPO 2.5% combination product was better than the combination with BPO 5% and similar to BPO 2.5% or 5% monotherapy. The combination product with BPO 5% induced significantly more irritation than BPO 5% monotherapy (P < .001) or BPO 10% monotherapy (P = .001). In conclusion, the new fixed-dose adapalene 0.1%-BPO 2.5% combination product provided the best overall cutaneous tolerability profile relative to BPO monotherapy. PMID:18441854

  17. Eficácia da combinação tópica de peróxido de benzoíla 5% e clindamicina 1% para o tratamento da hipomelanose macular progressiva: um estudo randomizado, duplo-cego, placebo-controlado Efficacy of topical combination of benzoyl peroxide 5% and clindamycin 1% for the treatment of progressive macular hypomelanosis: a randomized, doubleblind, placebo-controlled trial

    Directory of Open Access Journals (Sweden)

    Jussamara Brito Santos

    2011-02-01

    Full Text Available FUNDAMENTOS: A hipomelanose macular progressiva é uma dermatose sem etiologia definida. Não há consenso ou medicação de primeira linha para o seu tratamento e os tratamentos utilizados são pouco eficazes. OBJETIVO: Avaliar a eficácia terapêutica da combinação tópica de peróxido de benzoíla 5% e clindamicina 1% associada à exposição solar para o tratamento da hipomelanose macular progressiva. MATERIAIS E MÉTODOS: Trata-se de um estudo randomizado, duplo-cego, placebo-controlado, no qual os pacientes foram divididos em dois grupos: o Grupo A utilizou a combinação tópica de peróxido de benzoíla 5% e clindamicina 1% e o Grupo B usou um creme gel como placebo. Os pacientes foram orientados à exposição solar diária, avaliados e fotografados sistematicamente. Os dados coletados foram inseridos e analisados pelo software Epi Info. Definiu-se a significância estatística por valor de pBACKGROUND: Progressive macular hypomelanosis is a dermatosis without definite etiology. There is no consensus or first-line therapy in the treatment of progressive macular hypomelanosis, and the treatment options used are very little effective. OBJECTIVE: To evaluate the therapeutic efficacy of the topical combination of benzoyl peroxide 5% and clindamycin 1% associated with sun exposure for the treatment of progressive macular hypomelanosis. MATERIALS AND METHODS: This is a randomized, double-blind, placebo-controlled study in which patients were divided into two groups. Group A used the topical combination of benzoyl peroxide 5% and clindamycin 1% and Group B used gel cream as a placebo. Patients were advised to expose themselves to the sun on a daily basis and were systematically evaluated and photographed. The collected data were entered and analyzed using Epi Info. A p value < 0.05 was considered statistically significant. RESULTS: Out of the 23 patients included in the study, 13 were in group A and 10 in group B. Eleven patients (85% in

  18. 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

  19. 2-Benzoyl-4-chloroaniline thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    Katlen C. T. Bandeira

    2014-06-01

    Full Text Available In the title compound, C14H13ClN4S, obtained from a reaction of 2-benzoyl-4-chloroaniline with thiosemicarbazide in ethanol, the dihedral angle between the aromatic rings is 81.31 (13°. In the crystal, the molecules are linked by three N—H...S hydrogen bonds, forming centrosymmetric rings with set-graph motif R22(8 and R22(18, and resulting in the formation of a two-dimensional network lying parallel to (010.

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

    DEFF Research Database (Denmark)

    Hazlewood, C; Davies, Michael Jonathan

    1996-01-01

    radical generation, though there is controversy as to which radicals are responsible for this damage; previous workers have variously implicated benzoyloxyl (PhCO2,) phenyl (Ph.), and hydroxyl radicals (HO.) as the initiating agent. In the present study a detailed examination of the radicals generated on......, 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...

  1. 1-Benzoyl-3-(4-hydroxyphenylthiourea

    Directory of Open Access Journals (Sweden)

    Aisha A. Al-abbasi

    2010-12-01

    Full Text Available In the title compound, C14H12N2O2S, the aminophenol and the benzoyl groups adopt a syn–anti configuration with respect to the thiono C=S group across the thiourea C—N. The dihedral angle between the mean planes of the benzoyl and hydroxyphenyl rings is 36.77 (8°. The molecules are stabilized by intramolecular N—H...O hydrogen bonds. In the crystal, weak intermolecular C—H...O, O—H...S and N—H...O hydrogen bonds link the molecules into a chain along the c axis.

  2. Synthesis and Structure Elucidation of Benzoylated Deoxyfluoropyranosides

    OpenAIRE

    Esmurziev, Aslan M.; Simic, Nebojsa; Hoff, Bard Helge; Sundby, Eirik

    2010-01-01

    Benzoylated deoxyfluoropyranosides have been synthesized, starting with protected, unprotected, or fluorinated precursors. Fluorination of eight derivatives was compared using DAST and Deoxo-Fluor as reagents. Deoxo-Fluor was found to be especially useful in the fluorination of methyl 2,3,4-O-tribenzoyl -D-mannopyranoside and -D-glucopyranoside, resulting in better yields and avoiding the 1,6-methoxy migration experienced with DAST for one derivative. The two reagents gave comparable yields i...

  3. Synthesis of 1-Benzoyl-3-aryl-4-hydroxy-4-phenylimidazolidin-2-thiones

    Institute of Scientific and Technical Information of China (English)

    曾润生; 邹建平; 穆学军; 沈琪

    2003-01-01

    l-Benzoyl-3-aryl-4-hydroxy-4-phenylimidazolidin-2-thiones can be synthesized readily from the cyclization of 1-benzoyl-3-arylthioureas with bromine-acetophenone in the presence of excess triethylamiqe.

  4. 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...

  5. Selective determination of vanadium using N-benzoyl-N-phenylhydroxylamine

    International Nuclear Information System (INIS)

    Technique for selective spectrophotometric vanadium determination in alloys after extraction by chloroform of vanadium (5) complexes with N-benzoyl-N-phenylhydroxylamine from phosphoric acid solutions was developed. Low boundary of determination on sample dissolving ∼1 h. Effect of the nature of mineral acids and aliphatic alcohols on spectrophotometric characteristics of complexes was investigated

  6. 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

    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...

  7. 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.

  8. 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.

  9. Production of uranium peroxide

    International Nuclear Information System (INIS)

    The process of recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities, characterized by treating the uranyl solution with hydrogen peroxide in an amount sufficient to have an excess of at least 0.5 parts H2O2 per part vanadium (V2O5) above the stoichio-metric amount required to form the uranium peroxide, the hydrogen peroxide treatment being carried out in three sequential phases consisting of: 1) a precipitation phase in which the hydrogen peroxide is added to the uranyl solution to precipitate the uranium peroxide and the pH of the reaction media maintained in the range of 3.0 to 7.0 for a period of 5 to 180 60 minutes after the hydrogen peroxide addition; 2) a digestion phase in which the pH of the reaction medium is maintained in the range of 3.0 to 7.0 for a period of 5 to 180 minutes and 3) a final phase in which the pH of the reaction media is maintained in the range of 4.0 to 7.0 for a period of 1 to 60 minutes during which time the uranium peroxide is separated from the reaction solution containing the dissolved vanadium and sodium impurities, the excess hydrogen peroxide aforesaid being maintained until the uranium peroxide is separated from the reaction mixture

  10. Production of uranium peroxide

    International Nuclear Information System (INIS)

    The invention provides a process for recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities. It consists of treating the uranyl solution with hydrogen peroxide in an amount equal to at least 0.5 part H2O2 per part of vanadium (V2O5) in solution in excess of the stoichiometric (1.26 parts/part U3O8) amount required to form the uranium peroxide. The hydrogen peroxide treatment is carried out in three phases. (auth)

  11. Peroxo complexes of uranium(VI) with N-benzoyl urea and related ligands: synthesis, characterization and antifungal activity

    International Nuclear Information System (INIS)

    The peroxouranium(VI) complexes containing N-benzoyl urea and related ligands having composition (UO(O2)L-L(NO3)2).H2O (where L-L=N-benzoyl urea (NBU), N-benzoyl thiourea (NBT). N-benzoyl hydrazine (NBHz) and N-benzoyl hydroxylamine (NBHA)) are reported. The synthesized complexes have been characterized by various physico-chemical techniques, viz, elemental analysis, molar conductivity, magnetic susceptibility measurements, infra red, electronic, mass spectral and TGA/DTA studies. These studies revealed that the synthesized complexes are non-electrolytic and diamagnetic in nature. The ligands are bound to metal in a bidentate mode. Thermal analysis results provide conclusive evidence for the presence of water molecule in the complexes. Mass spectra confirm the molecular mass of the complexes. Antifungal activity of complexes revealed enhanced activity of complexes as compared to corresponding ligands. (author)

  12. 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

    OpenAIRE

    Aslıhan Kırkağaç; Zeynep Nurhan Saraçoğlu; Ayşe Esra Koku Aksu

    2015-01-01

    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 ...

  13. LIPID PEROXIDATION IN PREECLAMPSIA

    OpenAIRE

    T. Sharmila Krishna; D. Raja Rajeswari; E. Venkat Rao; Sk. Deepthi; Naidu, J.N.

    2015-01-01

    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...

  14. 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 (< 3.0 mg/kg) was difficult to be identified by infrared spectra with correlation coefficients between wheat flour and wheat flour samples contained 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.

  15. 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 (flour and wheat flour samples contained 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. PMID:26519920

  16. New benzoyl urea derivatives as novel NR2B selective NMDA receptor antagonists.

    Science.gov (United States)

    Borza, I; Greiner, I; Kolok, S; Galgóczy, K; Ignácz-Szendrei, Gy; Horváth, Cs; Farkas, S; Gáti, T; Háda, V; Domány, Gy

    2006-09-01

    A novel series of benzoyl urea derivatives was prepared and identified as NR2B selective NMDA receptor antagonists. The influence of the substitution of the piperidine ring on the biological activity of the compounds was studied. Compound 9 was active in the formalin test in mice. PMID:17020160

  17. 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

  18. 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

  19. 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.

  20. Benzoylation of anisole catalyzed by Ga/SBA-15 supported on carbon nanofibers composite

    OpenAIRE

    EL BERRICHI, F. Z.; Pham-Huu, C.; CHERIF, L.; Louis, B; M. J.; Ledoux

    2011-01-01

    Carbon nanofiber composite (C-NFC) shows several advantages compared to the conventional supports which are usually employed in catalysis such as alumina, silica or activated charcoal. In this present work we have developed a new hybrid catalyst consisting of SBA-15 supported on C-NFC for the benzoylation reaction. The structured materials allow an important improvement of the reaction hydrodynamics and favor the mass transfer between the active phase and the reactants, especially in the liqu...

  1. Synthesis and antiproliferative activity of novel 2-aryl-4-benzoyl-imidazole derivatives targeting tubulin polymerization

    OpenAIRE

    Chen, Jianjun; Li, Chien-Ming; Wang, Jin; Ahn, Sunjoo; Wang, Zhao; Lu, Yan; Dalton, James T.; Miller, Duane D.; Li, Wei

    2011-01-01

    We previously reported the discovery of 2-aryl-4-benzoyl-imidazoles (ABI-I) as potent antiproliferative agents for melanoma. To further understand the structural requirements for the potency of ABI analogs, gain insight in the structure-activity relationships (SAR), and investigate metabolic stability for these compounds, we report extensive SAR studies on the ABI-I scaffold. Compared with the previous set of ABI-I analogs, the newly synthesized ABI-II analogs have lower potency in general, b...

  2. Protein oxidation and peroxidation.

    Science.gov (United States)

    Davies, Michael J

    2016-04-01

    Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals 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 inhibit these pathways and this may contribute to the accumulation of modified proteins in cells. Available evidence supports an association between protein oxidation and multiple human pathologies, but whether this link is causal remains to be established. PMID:27026395

  3. 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.

  4. 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)

  5. Biosynthesis of benzoylformic acid from benzoyl cyanide with a new bacterial isolate of Brevibacterium sp. CCZU12-1.

    Science.gov (United States)

    He, Yu-Cai; Pan, Xue-He; Xu, Xiao-Feng; Wang, Li-Qun

    2014-03-01

    Brevibacterium sp. CCZU12-1 with high nitrilase activity could effectively hydrolyze benzoyl cyanide into benzoylformic acid. After the culture optimization, the preferred carbon sources, nitrogen sources, and inducer were glucose (10 g/L), a composite of peptone (10 g/L) plus yeast extract (2.5 g/L), and ε-caprolactam (2.0 mM), respectively. After the reaction optimization, the optimum reaction temperature, reaction pH, organic cosolvent, and metal ion were 30 °C, 7.0, ethanol (2%, v/v), and Ca(2+) (0.1 mM), respectively. At biotransformation of 120-mM benzoyl cyanide for 24 h, the yield of benzoylformic acid reached 91.8%. Moreover, the microbial nitrilase from Brevibacterium sp. CCZU12-1 could hydrolyze various nitriles, and it significantly exhibited high nitrilase activity against benzoyl cyanide, 3-cyanopyridine, and α-cyclohexyl-mandelonitrile. PMID:24504691

  6. 2-Benzoyl-4-chloro­aniline thio­semi­carbazone

    OpenAIRE

    Katlen C. T. Bandeira; Leandro Bresolin; Lehmann, Ueslei Z.; Priscilla J. Zambiazi; Adriano Bof de Oliveira

    2014-01-01

    In the title compound, C14H13ClN4S, obtained from a reaction of 2-benzoyl-4-chloro­aniline with thio­semicarbazide in ethanol, the dihedral angle between the aromatic rings is 81.31 (13)°. In the crystal, the mol­ecules are linked by three N—H⋯S hydrogen bonds, forming centrosymmetric rings with set-graph motif R 2 2(8) and R 2 2(18), and resulting in the formation of a two-dimensional network lying parallel to (010).

  7. Solvent extraction of lanthanide ions with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP)

    International Nuclear Information System (INIS)

    The solvent extraction of Er(3), Yb(3) and Lu(3) by 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5(HPMBP or HL) in carbon tetrachloride has been studied as a function of the pH of the aqueous phase and the concentration of the extractant in the organic phase. The equation for the extraction reaction has been suggested as: Ln3++3HL(0) rightleftdblarrow LnL3(0)+3H+(Ln3+ = Er, Yb, Lu). The extraction equilibrium constants (Kex) and two-phase stability constants (β3x) for the LnL3 complexes have been evaluated. (Author)

  8. Auto oxidation of plutonium with 3-phenyl-4-benzoyl-5-isoxazolone as an extractant

    International Nuclear Information System (INIS)

    Extraction of Pu (III) using 3-phenyl-4-benzoyl-5-isoxazolone (HPBI) was investigated in the presence of several reducing agents. It was observed that Pu (IV) was the dominating species extracted even though the aqueous phase comprised exclusively of Pu (III) initially. While aqueous reducing agents such as hydrazinium nitrate, hydroxyl ammonium nitrate, di-ethyl hydroxyl amine had no effect in suppressing the oxidation of Pu (III); organophilic t-butyl hydroquinone was found to be an effective holding reductant. The observed rate constants for the oxidation reaction were calculated and were found to be independent on the hydrogen ion concentration. (author)

  9. Design, synthesis, and insecticidal activities of new N-benzoyl-N'-phenyl-N'-sulfenylureas.

    Science.gov (United States)

    Sun, Ranfeng; Zhang, Yonglin; Chen, Li; Li, Yongqiang; Li, Qingshan; Song, Haibin; Huang, Runqiu; Bi, Fuchun; Wang, Qingmin

    2009-05-13

    A series of new N'-alkylaminothio, N'-arylaminothio (or dithio), and N',N'-thio (or dithio) derivatives of N-benzoyl-N'-phenylureas were designed and synthesized as insect-growth regulators with sulfur dichloride or disulfur dichloride as the original reactant. The new compounds were identified by (1)H nuclear magnetic resonancee (NMR) spectroscopy, elemental analysis [or high-resolution mass spectrometry (HRMS)], and single-crystal X-ray diffraction analysis. The X-ray results demonstrated that there exist N-S-N or N-S-S-N bonds in these new compounds. In comparison to the parent N-benzoyl-N'-phenylureas, these derivatives displayed better solubility. The insecticidal activities of the target compounds were evaluated. The results of bioassays showed that compounds 1-24 retained the larvicidal activities of the corresponding benzoylphenylureas (BPUs) and some compounds exhibited better larvicidal activities against oriental armyworm and mosquitoes than the parent BPUs. The larvicidal activities of the selected target compounds 1 and 24 against diamondback moth were better than that of the corresponding parent compounds E and triflumuron. PMID:19326865

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

    International Nuclear Information System (INIS)

    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

  11. Characterization of a newly synthesized organic nonlinear optical crystal: benzoyl valine

    Science.gov (United States)

    Kumar, T. K.; Selvaraj, R. S.; Janarthanan, S.; Rajan, Y. C.; Selvakumar, S.; Pandi, S.; Selvakumar, M. S.; Anand, D. P.

    2010-05-01

    Herein the synthesis and the crystal growth of benzoyl valine (BV), an organic nonlinear optical (NLO) material for frequency conversion was grown by slow evaporation solution growth technique at room temperature has been reported. The compound was prepared by Stockman method of benzoylation. The solubility curve shows linear nature up to a temperature of 313 K. XRD study reveals that the crystal belongs to monoclinic system with P21 non-centrosymmetric space group. The fundamental vibrational frequency of various functional groups (400-4000 cm-1) in the crystal was determined from FTIR analysis. 1H and 13C NMR spectral studies reveal the presence of proton and carbon network in the grown crystalline sample. The optical behaviour of the crystal was ascertained by optical UV absorption spectral studies. The UV cut off region (λmax) lies around 200 nm and the crystal is absolutely transparent from 220-800 nm suggesting its application as NLO material. The thermal stability of the crystal was determined by thermogravimetric and differential thermal analyses. Laser damage threshold of BV was found to be 0.34 GW/cm2 and hence BV can be used in frequency doubler system. Photoconductivity study of BV revealed negative photoconductiviting nature of the sample. The microhardness studies confirm that BV has a moderate Vickers hardness number (VHN) value in comparison to the other organic NLO crystals.

  12. Design, synthesis, and anti-melanogenic effects of (E-2-benzoyl-3-(substituted phenylacrylonitriles

    Directory of Open Access Journals (Sweden)

    Yun HY

    2015-08-01

    Full Text Available Hwi Young Yun,1 Do Hyun Kim,1 Sujin Son,1 Sultan Ullah,1 Seong Jin Kim,1 Yeon-Jeong Kim,2 Jin-Wook Yoo,1 Yunjin Jung,1 Pusoon Chun,2 Hyung Ryong Moon1 1College of Pharmacy, Pusan National University, Busan, 2College of Pharmacy, Inje University, Gimhae, Republic of Korea Background: Tyrosinase is the most prominent target for inhibitors of hyperpigmentation because it plays a critical role in melaninogenesis. Although many tyrosinase inhibitors have been identified, from both natural and synthetic sources, there remains a considerable demand for novel tyrosinase inhibitors that are safer and more effective. Methods: (E-2-Benzoyl-3-(substituted phenylacrylonitriles (BPA analogs with a linear β-phenyl-α,β-unsaturated carbonyl scaffold were designed and synthesized as potential tyrosinase inhibitors. We evaluated their effects on cellular tyrosinase activity and melanin biosynthesis in murine B16F10 melanoma cells and their ability to inhibit mushroom tyrosinase activity. Results: BPA analogs exhibited inhibitory activity against mushroom tyrosinase. In particular, BPA13 significantly suppressed melanin biosynthesis and inhibited cellular tyrosinase activity in B16F10 cells in a dose-dependent manner. A docking study revealed that BPA13 had higher binding affinity for tyrosinase than kojic acid. Conclusion: BPA13, which possesses a linear β-phenyl-α,β-unsaturated carbonyl scaffold, is a potential candidate skin-whitening agent and treatment for diseases associated with hyperpigmentation. Keywords: (E-2-benzoyl-3-(substituted phenylacrylonitriles, melanogenesis, tyrosinase inhibitor

  13. Method of precipitating uranium peroxide

    International Nuclear Information System (INIS)

    The uranium dissolved as uranyl tricarbonate ion in an aqueous alkaline solution is precipitated out as uranium peroxide. The precipitation is carried out by acidifying a portion of the aqueous alkaline solution with excess sulfuric acid to convert the uranyl tricarbonate ion to the uranyl ion and carbon dioxide. This is followed by the addition of hydrogen peroxide to the acidified solution to convert the uranyl ion to uranium peroxide precipitate, producing additional acid. Concurrently, a different portion of the aqueous alkaline uranyl tricarbonate solution is added to the precipitating solution to elevate the pH to an acidic range which is optimum for effective reaction to uranium peroxide and for its precipitation

  14. Liquid-liquid extraction of trivalent actinides and lanthanides with n-benzoyl-n-phenyl hydroxylamine

    International Nuclear Information System (INIS)

    Extraction of the trivalent actinides Am, Cm, Bk and Cf and the trivalent lanthanides Pm, Eu, Tb, Tm and Lu has been studied with N-benzoyl-N-phenyl hydroxylamine (HBPHA) in chloroform in the pH range 3.5-4.5. At pH 4.5 slopes of the log D vs. log [HBPHA] plots progressively decrease from 4 to 3 with increasing Z of the ions. Similar plots at pH 4.0 gave a uniform slope of 4 in all cases indicating the extraction of M (BPHA)3 HBPHA (M=An,Ln). In the pH ranges where this species is extracted log D vs. pH plots gave straight lines with slopes increasing from 2.0 to 2.7 with Z instead of the expected value of 3.0. Reasons for these abnormalities are discussed. (orig.)

  15. 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.

  16. Thermoanalytical study of N{sub {alpha}}-benzoyl-L-argininate ethyl ester chloride

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, A.C. [Department of Chemical Engineering, University of Coimbra, Polo II, Pinhal de Marrocos, Coimbra 3030-790 (Portugal); Jarmelo, S. [Department of Chemical Engineering, University of Coimbra, Polo II, Pinhal de Marrocos, Coimbra 3030-790 (Portugal); Department of Chemistry, University of Coimbra, Coimbra 3004-535 (Portugal); Canotilho, J. [Faculty of Pharmacy, University of Coimbra, Polo das Ciencias da Saude, Azinhaga de Santa Comba, Coimbra 3000-548 (Portugal); Eusebio, M.E.S.; Fausto, R. [Department of Chemistry, University of Coimbra, Coimbra 3004-535 (Portugal); Gil, M.H.; Simoes, P.N. [Department of Chemical Engineering, University of Coimbra, Polo II, Pinhal de Marrocos, Coimbra 3030-790 (Portugal)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer Thermal analysis of crystalline N{sub {alpha}}-benzoyl-L-argininate ethyl ester chloride. Black-Right-Pointing-Pointer Characterization by STA, MDSC, PLTM, and HiRes-MTGA. Black-Right-Pointing-Pointer Non-isothermal kinetic analysis of the thermal decomposition. - Abstract: N{sub {alpha}}-benzoyl-L-argininate ethyl ester chloride (BAEEH{sup +}{center_dot}Cl{sup -}) has been used as a model drug in the development of polymeric delivery systems for peptides and proteins. In this study, crystalline BAEEH{sup +}{center_dot}Cl{sup -} was characterized by different thermoanalytical techniques. The main thermal events were identified by modulated differential scanning calorimetry (MDSC). Polarized light thermomicroscopy (PLTM) showed that no phase transitions but fusion occur before thermal decomposition. A crystalline phase could not be obtained from the melt in cooling/heating cycles between 150 Degree-Sign C and -150 Degree-Sign C, at 10 Degree-Sign C min{sup -1} scanning rate. The thermal stability and the non-isothermal kinetic analysis of the thermal decomposition were studied by conventional and high resolution modulated thermogravimetric analysis (HiRes-MTGA). Depending on the conditions of the study, the decomposition starts in the range from 197 Degree-Sign C (HiRes-MTGA at {phi} = 2 Degree-Sign C min{sup -1}) to 261 Degree-Sign C (TGA at 20 Degree-Sign C min{sup -1}). It was found that the first stage of the decomposition process can be described by the kinetic triplet E{sub a} = 142 kJ mol{sup -1}, A = 1.86 Multiplication-Sign 10{sup 11} s{sup -1}, and f({alpha}) = (1 - {alpha}){sup 2.78}.

  17. Thermoanalytical study of Nα-benzoyl-L-argininate ethyl ester chloride

    International Nuclear Information System (INIS)

    Highlights: ► Thermal analysis of crystalline Nα-benzoyl-L-argininate ethyl ester chloride. ► Characterization by STA, MDSC, PLTM, and HiRes-MTGA. ► Non-isothermal kinetic analysis of the thermal decomposition. - Abstract: Nα-benzoyl-L-argininate ethyl ester chloride (BAEEH+·Cl−) has been used as a model drug in the development of polymeric delivery systems for peptides and proteins. In this study, crystalline BAEEH+·Cl− was characterized by different thermoanalytical techniques. The main thermal events were identified by modulated differential scanning calorimetry (MDSC). Polarized light thermomicroscopy (PLTM) showed that no phase transitions but fusion occur before thermal decomposition. A crystalline phase could not be obtained from the melt in cooling/heating cycles between 150 °C and −150 °C, at 10 °C min−1 scanning rate. The thermal stability and the non-isothermal kinetic analysis of the thermal decomposition were studied by conventional and high resolution modulated thermogravimetric analysis (HiRes-MTGA). Depending on the conditions of the study, the decomposition starts in the range from 197 °C (HiRes-MTGA at φ = 2 °C min−1) to 261 °C (TGA at 20 °C min−1). It was found that the first stage of the decomposition process can be described by the kinetic triplet Ea = 142 kJ mol−1, A = 1.86 × 1011 s−1, and f(α) = (1 − α)2.78.

  18. Lipid peroxidation of fish oils

    OpenAIRE

    Godwin, Angela; Prabhu, H. Ramachandra

    2006-01-01

    Fish and fish oils are the richest sources of ω-3 fatty acids. However, they are susceptible to lipid peroxidation due to their high degree of unsaturation. In the present study, the level of thiobarbituric acid reactive material in various fish oils available in the market with and without added Vitamin E was determined. The peroxide levels in fish oil heated to food frying temperature of 180°C and the effect of addition of vitamin E has also been studied. The results indicate that the perox...

  19. 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.

  20. Investigation into the hypersensitive transitions of Ln(III)-(1-phenyl-3-methyl-4-benzoyl pyrazolone-5) anthranilic acid and (1-phenyl-3-methyl-4-benzoyl-pyrazolone-5) aminoantipyrine complexes-II

    International Nuclear Information System (INIS)

    (1-phenyl-3-methy1-4-benzoyl pyrazolone-5) anthranilic acid (PMBAA) and (1-phenyl-3-methyl-4-benzoyl-pyrazolone-5) amino-antipyrine (PMBAAP) form complexes with lanthanides of the type [Ln(PMBAA)2NO3] and (Ln(PMBAAP)3] where Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Y. These compounds have been characterized from physico-chemical studies. The electronic spectra of the Nd(III) complexes have been studied in detail to investigate the phenomenon of hypersensitivity with respect to the coordination environment and solvent medium. In these compounds solvents do play a significant role to cause variation in hypersensitivity. In general Nd(III) PMBAA complexes showed greater hypersensitivity than the Nd(III) PMBAAP complexes. IR and NMR have also been interpreted. (author). 13 refs., 4 tabs

  1. Antimicrobial and antioxidant screening of N¢-substituted sulphonyl and benzoyl derivatives of 4-Pyridine carboxylic acid hydrazide.

    Science.gov (United States)

    Naeem, Sabahat; Akhtar, Shamim; Asghar, Nadia; Sherwani, Sikander Khan; Mushtaq, Nousheen; Kamil, Arfa; Zafar, Shaista; Arif, Mohammad; Saify, Zafar Saeed

    2015-11-01

    In this research program, the antibacterial, antifungal and antioxidant activities of six N'-substituted sulfonyl and benzoyl derivatives of lead molecule PCH were reported. Out of these compounds, sulphonyl derivatives 2,3 and benzoyl derivative 5 showed moderate to good activity against different strains of gram-positive and gram-negative bacteria including B. cereus, B. subtilis, B. thruingiensis and S. pyogenes, S. fecalis and E. coli ATCC 8739. Moreover, upon antifungal screening, the compound, N¢-[(2,4,6-trimethylbenzene) sulfonyl]pyridine-4-carbohydrazide possessed good antifungal activity against Candida species, a causative agent of systemic fungal infections. Antioxidant study demonstrated more than 50% inhibition in DPPH assay for sulphonyl derivative 2 indicating its potential as antioxidant while the other derivatives expressed low level of radical scavenging property. PMID:26639506

  2. 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

  3. Synthesis characterization and toxicity of lanthanide complexes with schiff bases derived from S-benzoyl dithiocarbazate and aldehydes

    International Nuclear Information System (INIS)

    New O:N:S and N:S donor ligands namely, S-benzoyl-N-(o-hydroxybenzaldehyde) dithiocarbazate, S-benzoyl-N-(N,N-dimethylaminobenzaldehyde ) dithiocarbazate, S-benzoyl-N(N-thiophene-2-aldehyde) dithiocarbazate and their complexes with La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Yb(III), and Lu(III) have been synthesized and characterized on the basis of elemental analysis, IR, NMR and electronic spectroscopy. The nephelauxetic effect(1-βoverlined), bonding parameter, βoverlined, bsup(1/2) and Sinha covalency parameter δ, have been calculated. Their positive values indicate covalent nature of metal-ligand bond which is also supported by their molar conductances measured in nitrobenzene. Magnetic moment values exhibit paramagnetic nature of the complexes. Log K,ΔG, ΔH and ΔS values have also been ca lculated. Toxicity of the compounds has been evaluated against cockroaches and fungi(Aspergillus flavus and A. niger). The LD50 and % inhibition values demonstrate greater efficacy of the complexes than that of the free bases. (author). 4 tabs., 12 refs

  4. 21 CFR 184.1366 - Hydrogen peroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydrogen peroxide. 184.1366 Section 184.1366 Food... Specific Substances Affirmed as GRAS § 184.1366 Hydrogen peroxide. (a) Hydrogen peroxide (H2O2, CAS Reg. No. 7722-84-1) is also referred to as hydrogen dioxide. It is made by the electrolytic oxidation...

  5. 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,...

  6. Purification of benzoyl-mercapto-acetyl-tri-glycine and ethyl cysteinate dimer complemented with biological evaluations

    International Nuclear Information System (INIS)

    Purification of benzoyl-mercaptoacetyl triglycine (MAG3) and ethyl cysteinate dimer (L,L-ECD) has been conducted through fractionated recrystallization of its impurities and isomers; biological behavior of the main isomers has been evaluated through biological distribution in mice. Chemical purity of synthesized MAG3 is 69,9%; after purification, 98, 12% is obtained from the compound with adequate biological distribution; fusion points range between 194 and 196oC before and after purification; recrystallization yields is 12%. Radiochemical purity of testing lot is 98%. In biological evaluations conducted in mice, injection dose percentages for the purest one, after 5 minutes, is 31,20% in kidneys and 1,14% in the liver. Chemical purity of synthesized ECD is 80,29%; after purification, 98,76% is obtained from the isomer with adequate biological activity; fusion points range between 195 and 197oC; yield percentage in recrystallization is 29%. radiochemical purity of testing lot is 97%; in biological evaluations conducted in mice, injection dose percentages for the purest one, after 5 minutes, is 1,37% in the brain, 25,70% in the liver and 13,40% in kidneys

  7. Red-phosphorescent OLEDs employing iridium (III) complexes based on 5-benzoyl-2-phenylpyridine derivatives

    International Nuclear Information System (INIS)

    A series of red-phosphorescent iridium (III) complexes 1-4 based on 5-benzoyl-2-phenylpyridine derivatives was synthesized. Their photophysical and electrophosphorescent properties were investigated. Multilayered OLEDs were fabricated with a device structure ITO/4,4',4''-tris(N-(naphtalen-2-yl)-N-phenyl-amino)triphenylamine (60 nm)/4,4'-bis(N-naphtylphenylamino)biphenyl (20 nm)/Ir(III) complexes (8%) doped in 4,4'-N,N'-dicarbazolebiphenyl (30 nm)/2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (10 nm)/tris(8-hydroxyquinolinyl)aluminum(III) (20 nm)/Liq (2 nm)/Al (100 nm). All devices exhibited efficient red emissions. Among those, in a device containing iridium complex 1 dopant, the maximum luminance was 14200 cd/m2 at 14.0 V. Also, its luminous, power, and quantum efficiency were 10.40 cd/A, 3.44 lm/W and 9.21% at 20 mA/cm2, respectively. The peak wavelength of the electroluminescence was 607 nm, with CIE coordinates of (0.615, 0.383) at 12.0 V, and the device also showed a stable color chromaticity with various voltages.

  8. Inorganic precursor peroxides for antifouling coatings

    DEFF Research Database (Denmark)

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

    2009-01-01

    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...... shown that it is possible to identify particulates that, when applied as pigments in antifouling coatings, will provide polishing and leaching rates comparable to those of Cu2O-based coatings. Furthermore, the combination of polishing and hydrogen peroxide leaching by a coating based on zinc peroxide in...... 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...

  9. Thermochemistry of cyclic acetone peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Sinditskii, V.P., E-mail: vps@rctu.ru [Mendeleev University of Chemical Technology, 9 Miusskaya Square, 125047 Moscow (Russian Federation); Kolesov, V.I.; Egorshev, V.Yu.; Patrikeev, D.I. [Mendeleev University of Chemical Technology, 9 Miusskaya Square, 125047 Moscow (Russian Federation); Dorofeeva, O.V. [Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow (Russian Federation)

    2014-06-01

    Highlights: • Old data on DADP and TATP enthalpies of formation have been revised. • Combining Gaussian-4 (G4) theory with an isodesmic reaction scheme allowed calculated enthalpies of formation of TATP and DADP. • Oxygen bomb calorimetry measurements allowed experimental enthalpies of formation of the peroxides. • Both experimental and calculated values show a satisfactory agreement between each other. • The newly obtained enthalpies reasonably account for the observed derivative parameters: heats of decomposition, combustion, and explosion. - Abstract: Two potentially initiating explosive peroxides, diacetonediperoxide (DADP) and triacetonetriperoxide (TATP), were studied in respect to their thermochemical properties. To get the internally self-consistent estimations of gas-phase enthalpy of formation of DADP and TATP, their values were calculated by combining Gaussian-4 (G4) theory with an isodesmic reaction scheme. The energies of combustion (Δ{sub c}U) were measured and the standard enthalpies of formation (Δ{sub f}H{sub 298}{sup °}) of DADP and TATP were derived using the standard enthalpies of formation of the combustion products. The heat of explosion was measured for small low-pressed charges of the peroxides. The obtained enthalpies of formation of DADP and TATP were found to agree well with quantum chemical calculations and reasonably account for the observed derivative parameters: heats of decomposition, combustion, and detonation.

  10. Thermochemistry of cyclic acetone peroxides

    International Nuclear Information System (INIS)

    Highlights: • Old data on DADP and TATP enthalpies of formation have been revised. • Combining Gaussian-4 (G4) theory with an isodesmic reaction scheme allowed calculated enthalpies of formation of TATP and DADP. • Oxygen bomb calorimetry measurements allowed experimental enthalpies of formation of the peroxides. • Both experimental and calculated values show a satisfactory agreement between each other. • The newly obtained enthalpies reasonably account for the observed derivative parameters: heats of decomposition, combustion, and explosion. - Abstract: Two potentially initiating explosive peroxides, diacetonediperoxide (DADP) and triacetonetriperoxide (TATP), were studied in respect to their thermochemical properties. To get the internally self-consistent estimations of gas-phase enthalpy of formation of DADP and TATP, their values were calculated by combining Gaussian-4 (G4) theory with an isodesmic reaction scheme. The energies of combustion (ΔcU) were measured and the standard enthalpies of formation (ΔfH298°) of DADP and TATP were derived using the standard enthalpies of formation of the combustion products. The heat of explosion was measured for small low-pressed charges of the peroxides. The obtained enthalpies of formation of DADP and TATP were found to agree well with quantum chemical calculations and reasonably account for the observed derivative parameters: heats of decomposition, combustion, and detonation

  11. Pork fat peroxidation by gamma-irradiation

    International Nuclear Information System (INIS)

    In this paper, pork fat peroxidation by γ-irradiation and the possible effects of oxygen, UV-irradiation and storage after the γ-irradiation have been investigated. It has been found that the level of peroxides in irradiated pork increases linearly with the increasing absorbed dose. The chemical yield of peroxides formed in the irradiated fat is about 4.2 and independent on the sample temperature or absorbed dose rate, but dependent on storage time of sample before γ-irradiation. The irradiated pork exhibits some unusual features as following: 1) the peroxide content in irradiated pork is higher than that in unirradiated one; 2) the peroxide content in irradiated pork increases gradually on storage and is essentially constant in unirradiated one, which is very useful for the detection of irradiated pork; 3) the further peroxidation in irradiated pork is much more susceptible to UV radiation than that in unirradiated pork

  12. 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.

  13. Extractive properties of benzohydroxamic and N-benzoyl-benzohydroxamic acids as analytical reagents towards six transition metal ions

    International Nuclear Information System (INIS)

    Two hydroxamic acids were prepared: benzohydroxamic and N-benzoyl benzohydroxamic acids. The former was prepared by coupling the free hydrox amine with benzoyl chloride with the ratio 1:1 in alkaline medium, where as the latter by the same procedure with the ratio 1:2 respectively, they were identified by their melting points, elemental analysis of their nitrogen contents. infra-red spectrophotometry, as well as their nitrogen using elevation of boiling point and the titration method to determine their molecular weights. The two hydroxamic acids were used as analytical reagents for the extraction of the metals Cr(vi), Fe(III), Ti(iv), Co(II) and U(vi). Benzohydroxamic acid has a maximum extraction 99.55% for Cr.(vi) 3M H2SO4, of 90.16% for Ti(iv) at pH 2.0,of 80.56% for Co(II) at pH 8.0 and 98.01% for U(vi) at pH 6.0. N-benzoyl benzohydroxamic acid has a maximum extraction of 96.45% for Cr(vi) at 3M H2So4, of 90.82% for Fe(III) at pH 4.0, of 97.02% for V(v) at 3M H2So4, of 83.56% for Ti(iv) at pH 2.0, of 89.82% for Co(II) at pH 8.0 and of 97.16% for U(vi) at pH 6.0. at the same pH of maximum extraction using heavy matrix, synthetic sea-water, benzohydroxamic acid has maximum values of 91.08%, of 77.99%, of 91.39%, of 87.50 and of 93.17% for Cr(vi), Fe(III), V(v), Ti(iv), Co9II) and U(vi) respectively whereas n-benzoyl benzohydroxamic acid has maximum values of 86.17%, of 77.78%, of 89.61%, of 75.66%, of 79.63% and of 91.18% for Cr(vi), Fe(III), V(v), Ti(iv), Co(II) and U(vi) respectively. The ratio of metal to ligand was determined utilizing the continuous variation method. It was 1 :2, 1: 1, 1 : 1, 1 : 2, 1: 2 and 1 : 2 with respect to Cr(vi), fe(III), Ti(iv), Co(II) and U(vi) respectively.(Author)

  14. 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.

  15. Evaluation of two forms of N-benzoyl-L-tyrosyl p-aminobenzoic acid in pancreatic function testing of dogs.

    Science.gov (United States)

    Burrows, C F; Orfely, C

    1989-01-01

    Plasma para-aminobenzoic acid (PABA) concentrations were compared in 12 dogs after oral administration of either a powdered suspension or a solution of N-benzoyl-L-tyrosyl-PABA. Peak PABA plasma concentrations were significantly higher at 30, 60 and 90 minutes after administration of the solution (P less than 0.05). As the solution may now be used as a clinical test, interpretation of the results by comparison with normal absorption curves obtained after administration of the suspension could contribute to a failure to diagnose canine exocrine pancreatic insufficiency. PMID:2784215

  16. Thermodynamic parameters for the extraction of some lanthanides with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 and trioctylamine

    International Nuclear Information System (INIS)

    The synergistic extraction of Pr, Gd and Yb with a mixture of 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 and trioctylamine diluted in C6H6, CHCl3 and CCl4 at 288 K, 298 K, 308 K and 318 K has been investigated. The values of the equilibrium constants as well as of ΔH0, ΔS0 and ΔG0 have been calculated. The thermodynamic parameters indicate that the adduct formed becomes stable on the account of the enthalpy change which exceeds the antistabilizing effect of the entropy factor. A comparison is made to the extraction of the same elements with thenoyltrifluoroacetone. (Author)

  17. Influence of the temperature on the extraction of some lanthanides with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5

    International Nuclear Information System (INIS)

    The extraction of Pr, Gd and Yb with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5(HPMBP) diluted in CHCl3, C6H6, and CCl4 at 288 K, 298 K, 308 K, and 318 K has been investigated. A compound of the type Me(PMBP)3HPMBP is formed in the organic phase. The values of the thermodynamic constants as well as of the parameters ΔH0, ΔS0 and ΔG0 have been determined. (Author)

  18. An efficient combination of Zr-MOF and microwave irradiation in catalytic Lewis acid Friedel-Crafts benzoylation.

    Science.gov (United States)

    Doan, Tan L H; Dao, Thong Q; Tran, Hai N; Tran, Phuong H; Le, Thach N

    2016-05-01

    A zirconium-based metal-organic framework, an effective heterogeneous catalyst, has been developed for the Friedel-Crafts benzoylation of aromatic compounds under microwave irradiation. Constructed by a Zr(iv) cluster and a linker 1,4-bis(2-[4-carboxyphenyl]ethynyl)benzene (H2CPEB), the MOF, possessing large pores and high chemical stability, was appropriate for the enhancement of Lewis acid activity under microwave irradiation. The reaction studies demonstrated that the material could give high yields for a few minutes and maintain its reactivity and structure over several cycles. PMID:27064371

  19. 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)-.

  20. Benzoyl chloride derivatization with liquid chromatography-mass spectrometry for targeted metabolomics of neurochemicals in biological samples.

    Science.gov (United States)

    Wong, Jenny-Marie T; Malec, Paige A; Mabrouk, Omar S; Ro, Jennifer; Dus, Monica; Kennedy, Robert T

    2016-05-13

    Widely targeted metabolomic assays are useful because they provide quantitative data on large groups of related compounds. We report a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method that utilizes benzoyl chloride labeling for 70 neurologically relevant compounds, including catecholamines, indoleamines, amino acids, polyamines, trace amines, antioxidants, energy compounds, and their metabolites. The method includes neurotransmitters and metabolites found in both vertebrates and insects. This method was applied to analyze microdialysate from rats, human cerebrospinal fluid, human serum, fly tissue homogenate, and fly hemolymph, demonstrating its broad versatility for multiple physiological contexts and model systems. Limits of detection for most assayed compounds were below 10nM, relative standard deviations were below 10%, and carryover was less than 5% for 70 compounds separated in 20min, with a total analysis time of 33min. This broadly applicable method provides robust monitoring of multiple analytes, utilizes small sample sizes, and can be applied to diverse matrices. The assay will be of value for evaluating normal physiological changes in metabolism in neurochemical systems. The results demonstrate the utility of benzoyl chloride labeling with HPLC-MS/MS for widely targeted metabolomics assays. PMID:27083258

  1. 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.

  2. Hydrogen peroxide as a greenhouse soil amendment

    Science.gov (United States)

    There are anecdotal reports that hydrogen peroxide provides growth benefits beyond controlling plant infection and plant stress. The objective of this research was to determine the effect of soil applications of hydrogen peroxide solutions on plant growth and flowering. Nasturtium (Tropaeolum maju...

  3. Molecular Association and Structure of Hydrogen Peroxide.

    Science.gov (United States)

    Giguere, Paul A.

    1983-01-01

    The statement is sometimes made in textbooks that liquid hydrogen peroxide is more strongly associated than water, evidenced by its higher boiling point and greater heat of vaporization. Discusses these and an additional factor (the nearly double molecular mass of the peroxide), focusing on hydrogen bonds and structure of the molecule. (JN)

  4. 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...

  5. 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... DRUGS, FEEDS, AND RELATED PRODUCTS CERTAIN OTHER DOSAGE FORM NEW ANIMAL DRUGS § 529.1150 Hydrogen peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen...

  6. 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.

  7. 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

  8. Synergistic extraction of uranyl and plutonyl ions with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP) and some some aliphatic sulphoxides

    International Nuclear Information System (INIS)

    Extraction of uranyl and plutonyl ions with 1-phenyl-3-methyl-4-benzoyl pyrazolone-5 (HPMBP) and some long chain aliphatic sulphoxides has been studied and the equilibrium constants for the organic phase addition reaction have been determined for both the systems. (author). 8 refs

  9. Correlations Between retention indices and molecular structure of aliphatic alcohols and of their benzoyl derivatives on phenyl substituted polysiloxane stationary phases

    International Nuclear Information System (INIS)

    The retention indices of aliphatic alcohols of carbon number up to Cg, and of their benzoyl derivatives up to C7, 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 -CH2- group increases I approximately 100 units, and in their benzoyl derivatives from 80 to 100 units. Dispersion indices Δl , and positional and structural increments δI, 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

  10. 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…

  11. 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

  12. Contribution to the study of the chemical effects of the (n, γ) reaction on copper N-benzoyl N-phenyl hydroxylaminate and copper N-benzoyl N-(o) Tolyl hydroxylaminate

    International Nuclear Information System (INIS)

    The influence of some factors such as pre-heating and pre-irradiation with gamma rays on the retention and thermal annealing of copper N-benzoyl N-phenyl hydroxylaminate and of copper N-benzolyl N-(o) tolyl hydroxylaminate is studied. The complexes were synthesized and characterized by determination of the melting-point, elemental analysis, X-ray diffraction, infra-red and visible range absoption spectrometry-thermogravimetric analysis were examined and the stability of the compounds was checked against heating and gamma irradiation from a 60Co source. Some experiments using the Szilard-Chalmers effect were carried out by irradiating the compound in the IEA-R1 nuclear reactor and calculating its specific activities. (M.J.C.)

  13. Extraction of lanthanide by 4-benzoyl-3-methyl-1-phenylpyrazol-5-one (HPMBP) in ionic liquid medium

    International Nuclear Information System (INIS)

    Solvent extraction of Lu by a beta diketone, 4-benzoyl-3-methyl-1- phenylpyrazol-5-one (HPMBP) in a RTIL, 1- methyl-3-octylimidazolium bis(trifluoromethylsulphonyl) imide, (C8mimNTf2) was studied as a function of aqueous acidity, and ligand concentration. The distribution ratio (D) of Lu decreased with increasing acidity. Metal-ligand stoichiometry was arrived at 1:3 by slope method of log-log plot. Similarly the dependence on H+ ion was also shown to be three. With this information, the extraction mechanism was proposed to be of typical of these type of acidic extractants, i.e. cation-exchange, which was not typical with this extractant dissolved in butyl analogue of above RTIL. (author)

  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. Mechanisms of wet oxidation by hydrogen peroxide

    International Nuclear Information System (INIS)

    A research programme is currently under way at BNL and MEL to investigate the possible use of Hydrogen Peroxide with metal ion catalysts as a wet oxidation treatment system for CEGB organic radioactive wastes. The published literature relating to the kinetics and mechanism of oxidation and decomposition reactions of hydrogen peroxide is reviewed and the links with practical waste management by wet oxidation are examined. Alternative wet oxidation systems are described and the similarities to the CEGB research effort are noted. (author)

  16. HOME BLEACHING TECHNIQUE USING CARBAMIDE PEROXIDE

    Directory of Open Access Journals (Sweden)

    Rahmi Alma Farah Adang

    2015-06-01

    Full Text Available There are two basic kinds of tooth whitening agents. The first is over the counter materials and the other is material used by the dentist or under dentist control. Home bleaching is a technique using 10% carbamide peroxide on a tray applied by patient under dentist supervision. This paper is a review of the effect of 10% carbamide peroxide home bleaching technique. It is revealed that this method is simple, safe, economic, and has short chairside time.

  17. Electrolytic process for producing hydrogen peroxide

    International Nuclear Information System (INIS)

    An electrolytic process for producing hydrogen peroxide in an aqueous alkaline solution includes simultaneously passing an aqueous alkaline electrolyte and oxygen through a fluid permeable conductive cathode comprising reticulated vitreous carbon foam, separating the fluid permeable conductive cathode from an anode by a barrier and connecting the fluid permeable conductive electrode and the anode with an external power source to cause generation of hydrogen peroxide ion within the aqueous alkaline solution

  18. Lipid Peroxidation and Antioxidant Status in Preeclampsia

    OpenAIRE

    S.V. Kashinakunti; Sunitha H; K. Gurupadappa; D.S. Shankarprasad; G.Suryaprakash; J.B Ingin

    2010-01-01

    The current theory suggests that in preeclampsia there is an increase in the lipid peroxidation products and leads to decrease in the serum antioxidants except uric acid, contributing to the pathogenesis of preeclampsia. In this context, this study was undertaken to determine the changes in blood levels of lipid peroxide and antioxidant levels in women with preeclampsia.Method: Case control study consisting of 30 preeclamptic and 30 healthy pregnant women. Fasting venous blood samples wer...

  19. Protein peroxides - key intermediates in oxidative damage?

    International Nuclear Information System (INIS)

    Proteins comprise a major target for reactive radicals and other oxidants in biological systems as a result of their abundance and high rate constants for reaction. Kinetic data suggest that proteins consume > 75% of the hydroxyl radicals generated by gamma radiation. Hydrogen atom abstraction from protein side-chains or the backbone gives rise to carbon-centred radicals, which react at diffusion-controlled rates to give peroxyl radicals. Current data suggests that the major decay route for these peroxyl radicals is via hydrogen atom- or electron-abstraction from neighbouring residues with resultant formation of a further protein radical (thereby initiating chain reactions) and a protein peroxide. These peroxides are major products of protein oxidation induced by a range of species including hydroxyl, alkoxyl and peroxyl radicals, metal ion-catalysed systems, peroxynitrite, activated white cells and singlet oxygen. The yield of these materials, based on the amount of initial oxidant, can be as high as 95%, though this depends on the species involved and the conditions used. These species can be formed in an essentially random manner on both side-chains and the backbone (e.g with hydroxyl radicals) or with great specificity (e.g. with singlet oxygen, where His, Trp and Tyr are the major targets). Some of these peroxides have been characterised. Protein peroxides have half-lives of minutes to days at 4 deg C but can decay rapidly at 37 deg C, or on exposure to UV light or metal ions. Peroxide decomposition can give further radicals, identified by EPR spin trapping, via cleavage of the peroxide bond. Evidence has been obtained for reaction of these protein peroxides, via both radical and non-radical pathways, with other cellular targets including other proteins (e.g. to give enzymatic inactivation), with lipids (thereby initiating peroxidation) and with DNA (to give 8-oxodG, strand breaks and DNA-protein cross-links)

  20. Hydrogen peroxide as a sustainable energy carrier: Electrocatalytic production of hydrogen peroxide and the fuel cell

    International Nuclear Information System (INIS)

    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.

  1. Troilite oxidation by hydrogen peroxide

    International Nuclear Information System (INIS)

    The kinetics and mechanism of troilite oxidation by H2O2 was studied at temperatures of 25 and 45 deg. C. Solutions within the range 0.1-0.85 mol L-1 H2O2 in HClO4 (0.01-0.1 mol L-1) were used as dissolution media. The experimental amount of dissolved iron was plotted versus t(n), with n ranging from 0.25 to 1.55. The theoretical interpretation of this dependence suggests that the troilite oxidation involves several processes: acidic troilite dissolution, FeS + 2H+ ↔ /SH2/ + /Fe2+/, where /SH2/ and /Fe2+/ are H2S and Fe2+ at troilite/sulfur rich layer (SRL) interface; /Fe2+/ migration into solution across SRL, and its rapid oxidation by hydrogen peroxide into ferric iron, 2Fe2+ + H2O2 + 2H+ 2Fe3+ + 2H2O; oxidation of /SH2/ sites to elemental sulfur, a process that contributes to sulfur enrichment of troilite surface, /SH2/ + 2Fe3+ S + 2Fe2+ + 2H+; oxidation of elemental sulfur to sulfate, a sulfur-consuming process, S + 3H2O2 = SO42- + 2H2O + 2H+. Both experimental results and theoretical considerations illustrate the importance of temperature, pH, and [H2O2] for the kinetics and mechanisms of troilite oxidation. The amounts of dissolved iron strongly increase with temperature and [H+], whereas an increase of H2O2 concentration seems to reduce the troilite oxidation. The reaction orders with respect to [H+] are variable, pointing out notable modifications of reaction mechanism with experimental conditions. The estimated value Ea 25.4 ± 0.9 kJ mol-1 ([H2O2] = 0.4 mol L-1 and pH 1) points to dissolution kinetics controlled by a mix regime of surface reaction and diffusion. (authors)

  2. Troilite oxidation by hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Chirita, Paul [Department of Inorganic and Analytical Chemistry, University of Craiova, Calea Bucuresti BB 107, Craiova 200512 (Romania); Descostes, Michael [CEA, DEN/DANS/DPC/SECR/Laboratory of Radionuclides Migration Measurements and Modelling, F-91191 Gif-sur-Yvette (France)

    2006-07-01

    The kinetics and mechanism of troilite oxidation by H{sub 2}O{sub 2} was studied at temperatures of 25 and 45 deg. C. Solutions within the range 0.1-0.85 mol L{sup -1} H{sub 2}O{sub 2} in HClO{sub 4} (0.01-0.1 mol L{sup -1}) were used as dissolution media. The experimental amount of dissolved iron was plotted versus t(n), with n ranging from 0.25 to 1.55. The theoretical interpretation of this dependence suggests that the troilite oxidation involves several processes: acidic troilite dissolution, FeS + 2H{sup +} {r_reversible} /SH{sub 2}/ + /Fe{sup 2+}/, where /SH{sub 2}/ and /Fe{sup 2+}/ are H{sub 2}S and Fe{sup 2+} at troilite/sulfur rich layer (SRL) interface; /Fe{sup 2+}/ migration into solution across SRL, and its rapid oxidation by hydrogen peroxide into ferric iron, 2Fe{sup 2+} + H{sub 2}O{sub 2} + 2H{sup +} 2Fe{sup 3+} + 2H{sub 2}O; oxidation of /SH{sub 2}/ sites to elemental sulfur, a process that contributes to sulfur enrichment of troilite surface, /SH{sub 2}/ + 2Fe{sup 3+} S + 2Fe{sup 2+} + 2H{sup +}; oxidation of elemental sulfur to sulfate, a sulfur-consuming process, S + 3H{sub 2}O{sub 2} = SO{sub 4}{sup 2-} + 2H{sub 2}O + 2H{sup +}. Both experimental results and theoretical considerations illustrate the importance of temperature, pH, and [H{sub 2}O{sub 2}] for the kinetics and mechanisms of troilite oxidation. The amounts of dissolved iron strongly increase with temperature and [H{sup +}], whereas an increase of H{sub 2}O{sub 2} concentration seems to reduce the troilite oxidation. The reaction orders with respect to [H{sup +}] are variable, pointing out notable modifications of reaction mechanism with experimental conditions. The estimated value E{sub a} 25.4 {+-} 0.9 kJ mol{sup -1} ([H{sub 2}O{sub 2}] = 0.4 mol L{sup -1} and pH 1) points to dissolution kinetics controlled by a mix regime of surface reaction and diffusion. (authors)

  3. [Hydrogen peroxide in artificial photosynthesizing systems].

    Science.gov (United States)

    Lobanov, A V; Komissarov, G G

    2014-01-01

    From the point of view of the concepts of hydrogen peroxide as a source of photosynthetic oxygen (hydrogen) coordination and photochemical properties of chlorophyll and its aggregates towards hydrogen peroxide were considered. The binding energy of H2O and H2O2 with chlorophyll and chlorophyllide depending on their form (monomers, dimers and trimers) was estimated by quantum chemical calculations. It is shown that at an increase of the degree of the pigment aggregation binding energy of H2O2 was more than the energy of H2O. Analysis of experimental results of the photochemical decomposition of hydrogen peroxide using chlorophyll was carried out. Estimates of the thermodynamic parameters (deltaG degrees and deltaH degrees) of the formation of organic compounds from CO2 with water and hydrogen peroxide were compared. The interaction of CO2 with H2O2 requires much less energy consumption than with water for all considered cases. The formation of organic products (formaldehyde, alcohols, carboxylic and carbonylic compounds) and simultaneous production of O2 under the influence of visible light in the systems of inorganic carbon--hydrogen peroxide--chlorophyll (phthalocyanine) is detected by GC/MS method, FTIR spectroscopy, and chemical analysis. PMID:25702472

  4. 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.

  5. Synthesis, characterization and biological evaluation of N-ferrocenylmethyl amino acid benzene carboxamide derivatives and N-ferrocenyl benzoyl amino alkane derivatives as anti-cancer agents.

    OpenAIRE

    Butler, William E.

    2012-01-01

    The aim of this research was to explore the structure-activity relationship (SAR) of ferrocenyl-bioconjugates. A series of N-(ferrocenylmethylamino acid)-fluorinated-benzene carboxamide derivatives and a series of N-(ferrocenyl)-benzoyl-aminoalkane derivatives have been synthesised, structurally characterised and biologically evaluated for their anti-proliferative activity on various cancer cell lines, principally, the (estrogen receptor positive) MCF-7 breast cancer cell line. The anti-c...

  6. Investigating The Molecular Formation Ppoperties of 2-Acetylamino-6-Benzoyl-4-Chlorophenol Using The Semi Emprical Molecular Orbital Methods (PM3, AM1, MNDO)

    OpenAIRE

    Fatma BAYSEN

    2004-01-01

    In this study in order to the geometry optimization of the 2-acetylamino-6-benzoyl-4-chlorophenol crystal, which is used for forming analgesic and antienflamatuar medicine and of which crystal structure was determined using x-ray diffraction method, PM3, AM1 and MNDO semi emprical molecular orbital methods found in the HyperChem program were used. By the geometry optimization geometric parameters of the molecules having the minimum energy were found.These values which were theoretically obtai...

  7. Palladium(ii)-catalyzed C-C and C-O bond formation for the synthesis of C1-benzoyl isoquinolines from isoquinoline N-oxides and nitroalkenes.

    Science.gov (United States)

    Li, Jiu-Ling; Li, Wei-Ze; Wang, Ying-Chun; Ren, Qiu; Wang, Heng-Shan; Pan, Ying-Ming

    2016-08-01

    C1-Benzoyl isoquinolines can be generated via a palladium(ii)-catalyzed C-C and C-O coupling of isoquinoline N-oxides with aromatic nitroalkenes. The reaction proceeds through remote C-H bond activation and subsequent intramolecular oxygen atom transfer (OAT). In this reaction, the N-O bond was designed as a directing group in the C-H bond activation as well as the source of an oxygen atom. PMID:27443150

  8. SYNTHESIS AND EVALUATION OF ANTIMICROBIAL ACTIVITY OF 1-BENZOYL-1H-PYRAZOLO [4,3-C]QUINOLIN-4(5H-ONES

    Directory of Open Access Journals (Sweden)

    Shivashankar Murugesh

    2011-01-01

    Full Text Available A series of 1-benzoyl-1H-pyrazolo [4,3-C]quinolin-4(5H-one, carrying appropriate substituents at the Quinoline ring have been synthesized in good yields via the condensation of 4-chloro-3-formylquinolin-2[1H]ones with benzohydrazide using triethylamine as a base. All the synthesized compounds were evaluated for their antibacterial activities.

  9. 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.

  10. 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...

  11. 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.

  12. 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.

  13. Inactivation of Escherichia coli glycerol kinase by 5'-[p-(fluorosulfonyl)benzoyl]adenosine: protection by the hydrolyzed reagent

    International Nuclear Information System (INIS)

    Incubation of Escherichia coli glycerol kinase with 5'-[p-(fluorosulfonyl)benzoyl]adenosine (FSO2BzAdo) at pH 8.0 and 250C results in the loss of enzyme activity, which is not restored by the addition of β-mercaptoethanol or dithiothreitol. The FSO2BzAdo concentration dependence of the inactivation kinetics is described by a mechanism that includes the equilibrium binding of the reagent to the enzyme prior to a first-order inactivation reaction in addition to effects of reagent hydrolysis. The hydrolysis of the reagent has two effects on the observed kinetics. The first effect is deviation from pseudo-first-order kinetic behavior due to depletion of the reagent. The second effect is the novel protection of the enzyme from inactivation due to binding of the sulfonate hydrolysis product. Determinations of the reaction stoichiometry with 3H-labeled FSO2BzAdo show that the inactivation is associated with the covalent incorporation of 1.08 mol of reagent/mol of enzyme subunit. Ligand protection experiments show that ATP, AMP, dAMP, NADH, 5'-adenylyl imidodiphosphate, and the sulfonate hydrolysis product of FSO2BzAdo provide protection from inactivation. The protection obtained with ATMP is not dependent on Mg2+. The results are consistent with modification by FSO2BzAdo of a single adenine nucleotide binding site per enzyme subunit

  14. Metabolic fate of N-benzoyl-N'-phenyl-2,6-diaminobenzoic acid in rats and guinea pigs

    International Nuclear Information System (INIS)

    The metabolism of N-benzoyl-N'-phenyl-2, 6-diaminobenzoic acid (F-1) was studied by a radiotracer technique. When 14C-F-1 was administered to rats and guinea pigs, benzoic acid, p-hydroxybenzoic acid, and glycine conjugates of these compounds were found in the urine as its metabolites. In the case of 3H-F-1 administration, it was possible to detect N-acetyl-N'-phenyl-2, 6-diaminobenzoic acid in the urine as a major metabolite. Rats and guinea pigs excreted in the feces a majority of radioactivity as unchanged F-1. The uptake of 3H-activity into the CMC pouch was considerably higher 12 hours after the oral administration of 3H-F-1 to inflamed rats. A large amount of unchanged F-1 rather than N-acetyl-N'-phenyl-2, 6-diaminobenzoic acid (metabolite 1) was found in the CMC pouch. On the other hand, in the liver the amount of metabolite 1 was larger than the unchanged parent compound F-1. These facts were taken into account in an attempt to determine the mode of action of the anti-inflammatory effect of F-1. (auth.)

  15. Characterization of some amino acid derivatives of benzoyl isothiocyanate: Crystal structures and theoretical prediction of their reactivity

    Science.gov (United States)

    Odame, Felix; Hosten, Eric C.; Betz, Richard; Lobb, Kevin; Tshentu, Zenixole R.

    2015-11-01

    The reaction of benzoyl isothiocyanate with L-serine, L-proline, D-methionine and L-alanine gave 2-[(benzoylcarbamothioyl)amino]-3-hydroxypropanoic acid (I), 1-(benzoylcarbamothioyl)pyrrolidine-2-carboxylic acid (II), 2-[(benzoylcarbamothioyl)amino]-4-(methylsulfanyl)butanoic acid (III) and 2-[(benzoylcarbamothioyl)amino]propanoic acid (IV), respectively. The compounds have been characterized by IR, NMR, microanalyses and mass spectrometry. The crystal structures of all the compounds have also been discussed. Compound II showed rotamers in solution. DFT calculations of the frontier orbitals of the compounds have been carried out to ascertain the groups that contribute to the HOMO and LUMO, and to study their contribution to the reactivity of these compounds. The calculations indicated that the carboxylic acid group in these compounds is unreactive hence making the conversion to benzimidazoles via cyclization on the carboxylic acids impractical. This has been further confirmed by the reaction of compounds I-IV, respectively, with o-phenylene diamine which was unsuccessful but gave compound V.

  16. 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.

  17. Design, synthesis and biological evaluation of 4-benzoyl-1-dichlorobenzoylthiosemicarbazides as potent Gram-positive antibacterial agents.

    Science.gov (United States)

    Paneth, Agata; Plech, Tomasz; Kaproń, Barbara; Hagel, Dominika; Kosikowska, Urszula; Kuśmierz, Edyta; Dzitko, Katarzyna; Paneth, Piotr

    2016-06-01

    Twelve 4-benzoyl-1-dichlorobenzoylthiosemicarbazides have been tested as potential antibacterials. All the compounds had MICs between 0.49 and 15.63 µg/ml toward Micrococcus luteus, Bacillus cereus, Bacillus subtilis and Staphylococcus epidermidis indicating, in most cases, equipotent or even more effective action than cefuroxime. In order to clarify if the observed antibacterial effects are universal, further research were undertaken to test inhibitory potency of two most potent compounds 3 and 11 on clinical isolates of Staphylococcus aureus. Compound 11 inhibited the growth of methicillin-sensitive S. aureus (MSSA) at MICs of 1.95-7.81 µg/ml, methicillin-resistant S. aureus (MRSA) at MICs of 0.49-1.95 µg/ml and MDR-MRSA at MIC of 0.98 and 3.90 µg/ml, respectively. Finally, inhibitory efficacy of 3 and 11 on planktonic cells and biofilms formation in clinical isolates of S. aureus and Haemophilus parainfluenzae was tested. The majority of cells in biofilm populations of MSSA and MRSA were eradicated at low level of 3, with MBICs in the range of 7.82-15.63 µg/ml. PMID:25897586

  18. Lipid Peroxidation and Antioxidant Status in Preeclampsia

    Directory of Open Access Journals (Sweden)

    S.V. Kashinakunti

    2010-01-01

    Full Text Available The current theory suggests that in preeclampsia there is an increase in the lipid peroxidation products and leads to decrease in the serum antioxidants except uric acid, contributing to the pathogenesis of preeclampsia. In this context, this study was undertaken to determine the changes in blood levels of lipid peroxide and antioxidant levels in women with preeclampsia.Method: Case control study consisting of 30 preeclamptic and 30 healthy pregnant women. Fasting venous blood samples were collected during antepartum period and serum levels of malondialdehyde, ascorbic acid (Vitamin C and uric acid were measured. In the preeclamptic group malondialdehyde (MDA, a lipid peroxidation product was significantly increased, while serum antioxidant ascorbic acid was significantly decreased (P< 0.001, where as uric acid level increased significantly (P<0.001. The findings of the present study are consistent with previous studies, suggesting that lipid peroxidation is an important factor in the pathogenesis of preeclampsia. In preeclampsia serum antioxidants are excessively utilized to counteract the cellular changes mediated by free radicals

  19. Crocidolite-induced lipid peroxidation. II. Role of antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Gulumian, M.; Kilroe-Smith, T.A.

    1987-12-01

    Asbestos fibers in vitro produce lipid peroxidation in rat lung microsomes. Butylated hydroxytoluene prevented this peroxidation. Ascorbate in low concentrations enhanced peroxidation of lipids but inhibited it at concentrations above 4 mmole/liter so that it partially protected membrane lipids from peroxidation produced by asbestos fibers. Reduced glutathione added to microsomes gave increased peroxidation at increased concentrations up to 20 mmol/liter. At 40 mmol/liter peroxidation was prevented. Glutathione had no obvious effect on the level of peroxidation produced by asbestos fibers. The 105,000g supernatant cell fraction added either with or without glutathione gave a decrease in the amount of lipid peroxidation produced by asbestos fibers. The protective action of these reducing agents suggests a possible use as prophylactic agents against the harmful effects of inhaled asbestos.

  20. 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)

  1. Structural diversity and chemical synthesis of peroxide and peroxide-derived polyketide metabolites from marine sponges.

    Science.gov (United States)

    Norris, Matthew D; Perkins, Michael V

    2016-07-28

    Covering: up to early 2016Marine sponges are widely known as a rich source of natural products, especially of polyketide origin, with a wealth of chemical diversity. Within this vast collection, peroxide and peroxide-derived secondary metabolites have attracted significant interest in the fields of natural product isolation and chemical synthesis for their structural distinction and promising in vitro antimicrobial and anticancer properties. In this review, peroxide and peroxide-derived polyketide metabolites isolated from marine sponges in the past 35 years are summarised. Efforts toward their synthesis are detailed with a focus on methods that utilise or attempt to elucidate the complex biosynthetic interrelationships of these compounds beyond enzymatic polyketide synthesis. Recent isolations, advances in synthetic methodology and theories of biogenesis are highlighted and critically evaluated. PMID:27163115

  2. Bactericidal and cytotoxic effects of hypothiocyanite-hydrogen peroxide mixtures.

    OpenAIRE

    Carlsson, J.; Edlund, M B; Hänström, L.

    1984-01-01

    Lactoperoxidase catalyzes the oxidation of thiocyanate by hydrogen peroxide into hypothiocyanite, a reaction which can protect bacterial and mammalian cells from killing by hydrogen peroxide. The present study demonstrates, however, that lactoperoxidase in the presence of thiocyanate can actually potentiate the bactericidal and cytotoxic effects of hydrogen peroxide under specific conditions, such as when hydrogen peroxide is present in the reaction mixtures in excess of thiocyanate. The toxi...

  3. Hydrogen peroxide excretion by oral streptococci and effect of lactoperoxidase-thiocyanate-hydrogen peroxide.

    OpenAIRE

    Carlsson, J.; Y. Iwami; Yamada, T.

    1983-01-01

    Approved type strains of Streptococcus sanguis, S. mitis, S. mutans, and S. salivarius were grown under aerobic and anaerobic conditions. The rate of hydrogen peroxide excretion, oxygen uptake, and acid production from glucose by washed-cell suspensions of these strains were studied, and the levels of enzymes in cell-free extracts which reduced oxygen, hydrogen peroxide, or hypothiocyanite (OSCN-) in the presence of NADH or NADPH were assayed. The effects of lactoperoxidase-thiocyanate-hydrog...

  4. Impact of hydrogen peroxide as a soil amendment on nasturtiums

    Science.gov (United States)

    Hydrogen peroxide, H2O2, is a highly reactive oxidizing agent naturally occurring in plants and animals. Plants produce hydrogen peroxide to destroy either their infected plant cells or the pathogens within their cells. Hydrogen peroxide also acts as a stress signal to plants. It is approved for c...

  5. Ionizing radiation and lipid peroxidation in human body

    International Nuclear Information System (INIS)

    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

  6. Grafting to Polymethylmethacrylate by the Radiation-Peroxidation Method

    International Nuclear Information System (INIS)

    Studies of the radiation-peroxidation of polymethylmethacrylate (PMMA) are discussed in relation to the subsequent grafting of vinyl pyrrolidone to the peroxidized polymer. The peroxidation has been investigated as a function of dose, PMMA molecular weight, and irradiation temperature. It is shown that low molecular weight PMMA is more effectively peroxidized and grafted at doses of a few megarads than a relatively high molecular weight polymer. It is also observed that increasing the temperature to about the glass sansition also increases peroxidation and grafting. The results are explained in terms to the effects of temperature and molecular weight on the mobility of polymer and fragment radicals. (author)

  7. Lipid Peroxidation in Psychiatric Illness: Overview of Clinical Evidence

    Directory of Open Access Journals (Sweden)

    Yash B. Joshi

    2014-01-01

    Full Text Available The brain is known to be sensitive to oxidative stress and lipid peroxidation. While lipid peroxidation has been shown to contribute to many disease processes, its role in psychiatric illness has not been investigated until recently. In this paper, we provide an overview of lipid peroxidation in the central nervous system as well as clinical data supporting a link between lipid peroxidation and disorders such as schizophrenia, bipolar disorder, and major depressive disorder. These data support further investigation of lipid peroxidation in the effort to uncover therapeutic targets and biomarkers of psychiatric disease.

  8. Extraction-spectrophotometric determination of vanadium in stainless steel and nickel-base alloys with N-benzoyl-N-phenylhydroxylamine

    International Nuclear Information System (INIS)

    A simple, rapid, and accurate extraction-spectrophotometric methods has been developed for the determination of vanadium in stainless steel and Ni-base alloys. The procedure is as follows: Take 0.5 g of sample into a beaker and add 20 ml of aqua regia, then heat and dissolve it. Furthermore add 5 ml of perchloric acid, and heat until the sample is dissolved, and add 14 ml of sulfuric acid (1 + 1) and 5 ml of phosphoric acid. Continue heating untill fumes of sulfuric acid generate from it. Thereafter, transfer it with use of water into a polyethylene separating funnel, add 10 ml of hydrofluoric acid (46%) and dilute to 50 ml with water. Then, add 4 ml of iron (II) ammonium sulfate solution (10%) and mix it thoroughly. Allow to stand for two or three min, and add 10 ml of ammonium peroxy-sulfate solution (45%) and mix it thoroughly again. By this procedure vanadium is oxidized to vanadium (V) without any oxidation of chromium (III). Allow to stand for about five minutes. Then add exactly 20 ml of N-benzoyl-N-phenylhydroxylamine chloroform solution (0.1%) and shake it vigorously for two min. Then, determine vanadium by measuring absorbance at the wavelength of 530 nm against a chloroform reference. The interference of chromium can be eliminated by reduction to Cr (III) with iron (II) ammonium sulfate, while manganese and molybdenum do not interfere at 530 nm. In the determination of 100 μg vanadium, the following amounts of foreign ions are tolerated: Fe (III) and Ni 1 g, Cr (III) 500 mg, Al 200 mg, Mo (VI) 100 mg, Mn, Co (II), Ti (IV) and Nb (V) 50 mg, Si 20 mg, Cu 10 mg, Ta (V) and W (VI) 5 mg. (author)

  9. 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.

  10. New hydrogen peroxide bioburden reduction specification

    Science.gov (United States)

    Kminek, Gerhard; Conley, Catharine

    2012-07-01

    The presentation will detail approved Planetary Protection specifications for the process of Vapor Hydrogen Peroxide (VHP) bioburden reduction for spacecraft components and subsystems. Outlined will be the research and studies on which the specifications were based. The research, funded by ESA and NASA/JPL, was conducted over a period of two years and was followed by limited material compatibility studies to assess the feasibility of this bioburden reduction modality for spacecraft.

  11. Hydrogen peroxide production in capillary underwater discharges

    Czech Academy of Sciences Publication Activity Database

    De Baerdemaeker, F.; Šimek, Milan; Leys, C.

    2007-01-01

    Roč. 40, č. 9 (2007), s. 2801-2809. ISSN 0022-3727 R&D Projects: GA AV ČR IAA1043403 Institutional research plan: CEZ:AV0Z20430508 Keywords : water breakdown * capillary * AC discharge * conductive liquid * hydrogen peroxide formation * initial rate * energy yield Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.200, year: 2007

  12. Hydrogen peroxide production in capillary underwater discharges

    Czech Academy of Sciences Publication Activity Database

    De Baerdemaeker, F.; Šimek, Milan; Člupek, Martin; Lukeš, Petr; Leys, C.

    2006-01-01

    Roč. 56, suppl. B (2006), s. 1132-1139. ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22nd./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA AV ČR(CZ) IAA1043403 Institutional research plan: CEZ:AV0Z20430508 Keywords : water * capillary * AC discharge * hydrogen peroxide formation * initial rate Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

  13. 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.

  14. Synthesis of n, n-bis(benzoyl) azelaic acid dihydrazide and its effect on performance of poly (l-lactic acid)

    International Nuclear Information System (INIS)

    In order to synthesize more function amides, N, N-bis(benzoyl) azelaic acid dihydrazide(NA(A)) was synthesized from benzoyl hydrazine and azelaoyl chloride which was deprived from azelaic acid via acylation. The influence of the reaction ratio, reaction time and reaction temperature to the yield of NA(A) was investigated by orthogonal experiment, the optimization result was: molar ratio of benzoyl hydrazine: azelaoyl chloride 2:3, reaction time 6 h, reaction temperature 70 degree C.The yield was 89.7%. Non-isothermal crystallization behavior measure indicated that NA(A) showed excellent nucleating effects on Poly(L-lactic acid)(PLLA) crystallization. Compared to the neat PLLA, with the addition of 0.8% NA(A), the crystallization temperature increased from 105.88 degree to 122.99 degree C,the degree of supercooling decreased from 55.33 degree C to 36.96 degree C while the crystallization enthalpy increased from 1.379 Jog/sup -1/ to 28.58 Jog/sup -1/ at a cooling rate of 1degree C/min from melt. The tensile strengths and tensile modulus increased with the increasing of NA(A) contents and possessed a maximum value for the critical NA(A) loading 0.3% and 0.5%, respectively. However, the elongations at break of PLLA/NA(A) samples decreased significantly. The hardness of PLLA/NA(A) samples after isothermal crystallization increased, and the largest value of hardness of PLLA/NA(A) with 1%NA(A) after isothermal crystallization was 176N/mm/sup 2/. (author)

  15. Experimental investigation of hydrogen peroxide RF plasmas

    Science.gov (United States)

    Barni, R.; Decina, A.; Zanini, S.; D'Orazio, A.; Riccardi, C.

    2016-04-01

    This work reports a detailed experimental study of the plasma properties in low pressure RF discharges in hydrogen peroxide and a comparison with argon under the same operating conditions. H2O2 plasmas have been proposed for sterilization purposes. Electrical properties of the discharge were shown to be similar, as for the RF and DC voltages of the driving electrode. Bulk plasma volume remains stable, concentrated in an almost cylindrical region between the two facing electrodes. It was found that the electron temperature is almost uniform across the plasma and independent of the power level. This is higher than in argon discharges: T e  =  4.6  ±  0.9 eV versus T e  =  3.3  ±  1.1 eV. The plasma density increases almost linearly with the power level and a substantial negative ion component has been ruled out in hydrogen peroxide. Dissociation in the plasma gas phase was revealed by atomic hydrogen and hydroxyl radical emission in the discharge spectra. Emission from hydroxyl and atomic oxygen demonstrates that oxidizing radicals are produced by hydrogen peroxide discharges, revealing its usefulness for plasma processing other than sterilization, for instance to increase polymer film surface energy. On the other hand, argon could be considered as a candidate for the sterilization purposes due to the intense production of UV radiation.

  16. THE STRUCTURE OF 3,5-DI-O-BENZOYL-1,2-DIDEOXY-1-PHENYL-BETA-D-RIBOFURANOSE, C25H22O5

    OpenAIRE

    GUNNING, J.; Neidle, S; MILLICAN, T.; Eaton, M; MOCK, G.; Mann, J.

    1985-01-01

    Mr=402.4, orthorhombic, P212~2 l, a= 4-946 (1), b= 15.887 (2), c=26.555 (2)A, V= 2086.7 (5) A 3, Z = 4, D x = 1.28 gcm -a, Cu Ka, 2 = 1.5418/k, B = 6.868 cm -1, F(000) = 848, T= 293 K, final R =0.054 for 648 observed reflections. The molecule is propeller shaped. The benzoyl groups act as protecting groups and the phenyl group is a base substitute. The crystal structure does not involve any intermolecular stacking interactions between the phenyl groups. The molecule...

  17. Synthesis of a Novel Benzoyl Adenosine Analog Containing a 1, 4-Dioxane Sugar Analog and the Synthesis of a Corresponding Uracil Adenine Dinucleotide

    Directory of Open Access Journals (Sweden)

    Per Carlsen

    2011-05-01

    Full Text Available Adenosine analogs in which the sugar unit was replaced by a 1,4-dioxane sugar equivalent, were prepared by coupling the 1,4-dioxane sugar analog as its anomeric acetates, with N6-benzoyl protected adenine. The 1,4-dioxane system was obtained in an enantioselective synthesis from (R,R-dimethyl tartrate. Using standard phosphorimidite methodology, the adenine analog was further reacted with a 1,4-dioxane uridine analog to give the corresponding, protected dinucleotide, set-up for further condensation into larger oligonucleotides.

  18. N-(4-Substituted-benzoyl)-N'-(beta-d-glucopyranosyl)ureas as inhibitors of glycogen phosphorylase: Synthesis and evaluation by kinetic, crystallographic, and molecular modelling methods

    OpenAIRE

    Veronika Nagy; Nora Felfoeldi; Balint Konya; Praly, Jean-Pierre; Tibor Docsa; Pal Gergely; Chrysina, Evangelia D.; Tiraidis, Costas; Kosmopoulou, Magda N.; Alexacou, Kyra-Melinda; Konstantakaki, Maria; Leonidas, Demetres D.; Zographos, Spyros E.; Oikonomakos, Nikos G.; Kozmon, Stanislav

    2012-01-01

    N-(4-Substituted-benzoyl)-N'-(beta-D-glucopyranosyl)ureas (substituents: Me, Ph, Cl, OH, OMe, NO2, NH2, COOH, and COOMe) were synthesised by ZnCl2 catalysed acylation of O-peracetylated beta-D-glucopyranosyl urea as well as in reactions of O-peracetylated or O-unprotected glucopyranosylamines and acyl-isocyanates. O-deprotections were carried out by base or acid catalysed transesterifications where necessary. Kinetic studies revealed that most of these compounds were low micromolar inhibitors...

  19. Potentiometric studies on the chelation behaviour of ω-benzoyl-2-hydroxy-4-methoxy-3-methyl-acetophenone (BHMMA) with lanthanons

    International Nuclear Information System (INIS)

    The chelation behaviour of complexes of La(3), Pr(3), Nd(3), Sm(3), Y(3), Tb(3), Dy(3), Ho(3) with ω-benzoyl-2-hydroxy-4-methoxy-3-methyl-acetophenone has been studied potentiometrically in 75% (v/v) aqueous alcohol medium at various ionic strengths. The method of Bjerrum and Calvin, as modified by Irving and Rossotti, has been used to find values of n-bar and pL. The stability constants and the values of Smin have been calculated. The order of stability constants was found to be: La < Pr < Nd < Sm < Y < Tb < Dy < Ho. (Author)

  20. Lipid Peroxidation and Antioxidant Status in Preeclampsia

    Directory of Open Access Journals (Sweden)

    Rokeya Begum

    2011-07-01

    Full Text Available Background: Preeclampsia is the most common and major medical complication of pregnancy with a high incidence of maternal and foetal morbidity and mortality. During pregnancy abnormally increased lipid peroxidation and free radical formation as well as significantly decreased antioxidants production in maternal blood may lead to pathogenesis of preeclampsia. So, we designed this study as little information is known about lipid peroxidation and antioxidant level in preeclampsia. Objectives: To assess the serum malondialdehyde (MDA level as a lipid peroxidation product and vitamin E (antioxidant level in women with preeclampsia as well as in normal pregnancy and to compare the values. Materials and Methods: The study was conducted on 60 women aged from 25 to 35 years in the department of Biochemistry, Budi Kemuliaan Maternity Hospital (BKMH in Jakarta during the period April to July 2004. Twenty were normal pregnant women and 20 were preeclamptic patients. For comparison age matched 20 apparently healthy nonpregnant women were included in the study. The study subjects were selected from outpatient department (OPD of Obstetrics and Gynaecology of BKMH in Jakarta. Serum MDA (lipid peroxidation product level was measured by thiobarbituric acid reactive substances assay (TBRAS method and vitamin E was estimated spectroflurometrically. Data were analyzed by unpaired Student’s t test between the groups by using SPSS version 12. Results: The mean serum MDA levels were significantly higher in normal pregnancy and also in preeclampsia than that of nonpregnant control group women (p<0.001. Again the serum MDA levels were significantly higher in preeclampsia than that of normal pregnant women (p<0.001. The serum vitamin E levels were significantly lower in preeclampsia and also in normal pregnancy than that of nonpregnant control women (p<0.001. Moreover, the serum vitamin E levels were significantly lower in preeclampsia compared to that of normal

  1. Embryotoxic effects of eight organic peroxides and hydrogen peroxide on three-day chicken embryos

    Energy Technology Data Exchange (ETDEWEB)

    Korhonen, A.; Hemminki, K.; Vainio, H.

    1984-02-01

    Nine peroxides used in rubber processing were tested for embryotoxicity in 3-day chicken embryos using the air chamber method. The potencies were expressed by the ED/sub 50/ for the total embryotoxic effect of the chemicals, including deaths and malformations, up to Day 14 of the incubation. The range of the ED/sub 50/'s was from 0.13 to 2.7 ..mu..moles per egg and the order of the potencies was as follows: cyclohexanoneperoxide > cumolhydroperoxide > ethylmethylketoneperoxide > dibenzoylperoxide > acetylacetoneperoxide > perbenzoic acid-tert-butylester > dicumylperoxide > dialauroylperoxide > hydrogen peroxide. All nine peroxides caused malformations at a moderate frequency. The maximum percentage of malformed embryos of the treated varied from the 16% of perbenzoic acid-tert-butylester to the 56% of dicumylperoxide. The high percentage caused by the latter could, however, result from slow diffusion of high lethal doses from the air chamber to the embryo.

  2. NMR and DFT Calculation Study on Structures of 2-[2-nitro-4-(trifluoromethyl)benzoyl]cyclohexane-1,3-dione (NTBC) and Its Two Metabolites Isolated from Urine of Patients Suffering from Tyrosinemia Type I.

    OpenAIRE

    Gryff-Keller, Adam; Szczeciński, Przemysław; Kraska-Dziadecka, Anna

    2010-01-01

    Abstract 2-[2-Nitro-4-(trifluoromethyl)benzoyl]cyclohexane-1,3-dione (NTBC) is an active component of nitisinone, a medicine against tyrosinemia type I. Using 1H, 13C and 19F NMR spectroscopy it has been found that in urine of patients treated with nitisinone two compounds possessing CF3 group are always present. They have been isolated by TLC technique and identified as 4-hydroxy-2-[2-nitro-4-(trifluoromethyl)benzoyl]cyclohexane-1,3-dione and 5-hydroxy-2-[2-nitro-4-(trifluoromethy...

  3. Identification of 2-[2-nitro-4-(trifluoromethyl)benzoyl]- cyclohexane-1,3-dione metabolites in urine of patients suffering from tyrosinemia type I with the use of 1H and 19F NMR spectroscopy.

    Science.gov (United States)

    Szczeciński, Przemysław; Lamparska, Diana; Gryff-Keller, Adam; Gradowska, Wanda

    2008-01-01

    Organic extracts of six urine samples from children treated with nitisinone, a medicine against tyrosinemia type I, were investigated by (1)H and (19)F NMR spectroscopy. The presence of unchanged 2-[2-nitro-4-(trifluoromethyl)benzoyl]cyclohexane-1,3-dione (NTBC), 6-hydroxy-2-[2-nitro-4-(trifluoromethyl)benzoyl]cyclohexane-1,3-dione (NTBC-OH) and 2-nitro-4-trifluoromethylbenzoic acid (NTFA) as well as a few other unidentified compounds containing CF(3) group was documented. PMID:19039335

  4. Identification of 2-[2-nitro-4-(trifluoromethyl)benzoyl]-cyclohexane-1,3-dione metabolites in urine of patients suffering from tyrosinemia type I with the use of 1H and 19F NMR spectroscopy

    International Nuclear Information System (INIS)

    Organic extracts of six urine samples from children treated with nitisinone, a medicine against tyrosinemia type I, were investigated by 1H and 19F NMR spectroscopy. The presence of unchanged 2-[2-nitro-4-(trifluoromethyl)benzoyl]cyclohexane-1,3-dione (NTBC), 6-hydroxy-2-[2-nitro- 4-(trifluoromethyl)benzoyl]cyclohexane-1,3-dione (NTBC-OH) and 2-nitro-4-trifluoromethylbenzoic acid (NTFA) as well as a few other unidentified compounds containing CF3 group was documented. (authors)

  5. MICROWAVE ASSISTED SYNTHESIS OF 3-(2-BENZOYL-6-HYDROXY-3-METHYL BENZO[b] FURAN-5-YL-5-(ARYL-4, 5-DIHYDRO-1H-PYRAZOLE CARBOTHIOAMIDES AND THEIR ANTIBACTERIAL ACTIVITY Mikrowellen unterstützte Synthese von 3 - (2-Benzoyl-6-HYDROXY-3-METHYL Benzo [b] furan-5-yl -5 - (ARYL -4, 5-DIHYDRO-1H-pyrazol CARBOTHIOAMIDES UND ihre antibakterielle Aktivität

    Directory of Open Access Journals (Sweden)

    Ashok D, Sudershan K,Khalilullah M

    2011-10-01

    Full Text Available A series of 3-(2-Benzoyl-6-hydroxy-3-methyl benzo[b] furan-5-yl-5-(aryl-4, 5-dihydro-1Hpyrazole carbothioamides have been prepared by the reaction of (E-1-(2-Benzoyl-6-hydroxy-3- methylbenzo[b]furan-5-yl-3-aryl-2-propen-1-ones with thiosemicarbazide in the presence of sodium hydroxide under microwave irradiation. The structures of newly synthesized compounds have been confirmed on the basis of elemental analysis, IR,1H-NMR,13C-NMR and mass spectral data. All the compounds were screened for their antibacterial activity.

  6. N-(4-Substituted-benzoyl)-N'-(β-d-glucopyranosyl)ureas as inhibitors of glycogen phosphorylase: Synthesis and evaluation by kinetic, crystallographic, and molecular modelling methods.

    Science.gov (United States)

    Nagy, Veronika; Felföldi, Nóra; Kónya, Bálint; Praly, Jean-Pierre; Docsa, Tibor; Gergely, Pál; Chrysina, Evangelia D; Tiraidis, Costas; Kosmopoulou, Magda N; Alexacou, Kyra-Melinda; Konstantakaki, Maria; Leonidas, Demetres D; Zographos, Spyros E; Oikonomakos, Nikos G; Kozmon, Stanislav; Tvaroška, Igor; Somsák, László

    2012-03-01

    N-(4-Substituted-benzoyl)-N'-(β-d-glucopyranosyl) ureas (substituents: Me, Ph, Cl, OH, OMe, NO(2), NH(2), COOH, and COOMe) were synthesised by ZnCl(2) catalysed acylation of O-peracetylated β-d-glucopyranosyl urea as well as in reactions of O-peracetylated or O-unprotected glucopyranosylamines and acyl-isocyanates. O-deprotections were carried out by base or acid catalysed transesterifications where necessary. Kinetic studies revealed that most of these compounds were low micromolar inhibitors of rabbit muscle glycogen phosphorylase b (RMGPb). The best inhibitor was the 4-methylbenzoyl compound (K(i)=2.3μM). Crystallographic analyses of complexes of several of the compounds with RMGPb showed that the analogues exploited, together with water molecules, the available space at the β-pocket subsite and induced a more extended shift of the 280s loop compared to RMGPb in complex with the unsubstituted benzoyl urea. The results suggest the key role of the water molecules in ligand binding and structure-based ligand design. Molecular docking study of selected inhibitors was done to show the ability of the binding affinity prediction. The binding affinity of the highest scored docked poses was calculated and correlated with experimentally measured K(i) values. Results show that correlation is high with the R-squared (R(2)) coefficient over 0.9. PMID:22325154

  7. Stabilization of the bicontinuous cubic phase in siloxane-terminated mesogens, 1,2-bis[4'-(n-(oligodimethylsiloxyl)alkoxy)benzoyl]hydrazine.

    Science.gov (United States)

    Kutsumizu, Shoichi; Tokiwa, Issei; Kawafuchi, Akane; Miwa, Yohei; Yamamura, Yasuhisa; Saito, Kazuya

    2016-03-23

    The introduction of oligodimethyl siloxane segments at the termini of the alkyl tails has been employed to stabilize the bicontinuous cubic (Cubbi) phase of a chain-core-chain type molecule having a 1,2-bis(benzoyl)hydrazine central core with two chains attached at the 4' position of each benzoyl moiety. In this study, three silylated molecules, , , and , were synthesized, where "CnSim" represents the number of carbon and silicon atoms in the chain and "bis" indicates the two chains being the same, whereas the last one is asymmetric with respect to the core. The phase behaviors were examined by using polarized optical microscopy, differential scanning calorimetry, and X-ray diffraction techniques. All three compounds form Cubbi phases and their syntheses were compared including their parent compound . It was clearly revealed that the introduction of oligodimethyl siloxane segments effectively suppresses the crystallization at low temperatures, and as a result stabilizes the Cubbi phases, in an extreme case down to room temperature. The semi-quantitative analyses in terms of lattice constant and three-dimensional electron density map help us to better understand the self-assembly process in the Cubbi phases. The study also revealed that the introduction of oligodimethyl siloxane segments is not only an alternative for the hydrocarbon segment but also is able to provide a versatile design strategy for obtaining stable Cubbi phases. PMID:26965052

  8. 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...... application in RAS by addressing disinfection demand and identify efficient and safe water treatment routines....

  9. Ultrasonic radiation induced lipid peroxidation in liposomal membrane

    Energy Technology Data Exchange (ETDEWEB)

    Jana, A.K.; Agarwal, S.; Chatterjee, S.N.

    1986-12-01

    Ultrasonic radiation produced a dose dependent linear increase in lipid peroxidation (MDA formation) in the liposomal membrane. The yield of MDA was significantly inhibited by butylated hydroxytoluene (BHT), the antioxidant, sodium formate,the OH/sup ./ radical scavenger, and EDTA, the metal ion chelator. Ascorbic acid at low concentration increased the ultrasonic induced MDA formation while high concentrations inhibited lipid peroxidation. A mechanism of ultrasound induced lipid peroxidation is suggested.

  10. Antioxidant effect of bisphosphonates and simvastatin on chondrocyte lipid peroxidation

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate the effect of bisphosphonates (BPs) and simvastatin on chondrocyte lipid peroxidation. For this purpose, a flow cytometrical method using C11-BODIPY581/591 was developed to detect hydroperoxide-induced lipid peroxidation in chondrocytes. Tertiary butylhydroperoxide (t-BHP) induced a time and concentration dependent increase in chondrocyte lipid peroxidation. Addition of a Fe2+/EDTA complex to t-BHP or hydrogen peroxide (H2O2) clearly enhanced lipid peroxidation. The lipophilic simvastatin demonstrated a small inhibition in the chondrocyte lipid peroxidation. None of three tested BPs (clodronate, pamidronate, and risedronate) had an effect on chondrocyte lipid peroxidation induced by t-BHP. However, when Fe2+/EDTA complex was added to t-BHP or H2O2, BPs inhibited the lipid peroxidation process varying from 25% to 58%. This study demonstrates that BPs have antioxidant properties as iron chelators, thereby inhibiting the chondrocyte lipid peroxidation. These findings add evidence to the therapeutic potential of bisphosphonates and statins in rheumatoid arthritis

  11. Lipid Peroxidation and Lipid Metabolism in Postmenopausal Women

    OpenAIRE

    , Banu ÖNVURAL

    1998-01-01

    The aims of this study were to determine the degree of lipid peroxidation in the sera of postmenopausal women and compare this with the lipid peroxidation of a premenopausal group, and to see if there was any correlation between lipid parameters and lipid peroxidation within the groups. We assayed the lipid profiles and malondialdehyde (MDA), a marker for lipid peroxidation, in a postmenopausal group (n=57, mean age=49.4±6.6), an age-matched male group (n=21, mean age=48.5±6.7) an...

  12. Hydrogen peroxide leaching of uranium in carbonate solutions

    International Nuclear Information System (INIS)

    The kinetics of UO2 dissolution in ammoniacal carbonate solutions were investigated with hydrogen peroxide as an oxidant. The effects of hydrogen peroxide concentration, total carbonate concentration and pH were studied. For similar conditions, the rate of dissolution was considerably faster with hydrogen peroxide than with oxygen. The reaction was found to be of 0.5 order with respect to both hydrogen peroxide and total carbonate concentrations. At pH values below approximately 10, the rate was relatively insensitive to pH. These results are consistent with an electrochemical surface reaction similar to that developed for the oxygen-leaching system. Electrochemical interpretation adequately explain the enhanced rate of dissolution observed for hydrogen peroxide leaching. The decomposition of hydrogen peroxide in alkaline solutions is discussed. Surface-electrode potentials are used to explain the catalytic activity of various solids. Hydrogen peroxide was found to decompose rapidly in the presence of freshly precipitated ferric hydroxide. The effect of pH on the rate of hydrogen peroxide decomposition was investigated in the pH range 4.3 to 11.2. Problems associated with the use of hydrogen peroxide in the in-situ leaching of uranium are considered. (author)

  13. 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.

  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 (ppermeable than were the dentin and enamel surfaces. PMID:22621165

  15. Precipitation of uranium concentrates by hydrogen peroxide

    International Nuclear Information System (INIS)

    An experimental study on the (UO4.xH2) uranyl peroxide precipitation from a uranium process strip solution is presented. The runs were performed in a batch reactor, in laboratory scale. The main objective was to assess the possibility of the peroxide route as an alternative to a conventional ammonium diuranate process. The chemical composition of process solution was obtained. The experiments were conducted according to a factorial design, aiming to evaluate the effects of initial pH, precipitation pH and H2O2/UO22+ ratio upon the process. The responses were measured in terms of the efficiency of U precipitation, the content of U in the precipitates and the distribution of impurities in the precipitates. The results indicated that the process works is satisfactory on the studied conditions and depending on conditions, it is possible to achieve levels of U precipitation efficiency greater than 99.9% in reaction times of 2 hours. The precipitates reach grades around 99% U3O8 after calcination (9000C) and impurities fall below the limit for penalties established by the ASTM and the Allied Chemical Standards. The precipitates are composed of large aggregates of crystals of 1-4 μm, are fast settling and filtering, and are free-flowing when dry. (Author)

  16. 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...

  17. 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.

  18. 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

  19. EVALUATION OF THE STRUCTURAL AND MOLECULAR WEIGHT CHANGES OF LIGNIN DURING THE TREATMENT OF HARDWOOD ALKALINE PEROXIDE MECHANICAL PULP WITH LACCASE AND A LACCASE-MEDIATOR-SYSTEM

    Directory of Open Access Journals (Sweden)

    Yu Liu,

    2012-07-01

    Full Text Available Alkaline Peroxide Mechanical Pulp (APMP of triploid of Populus tomentosa was modified by laccase and a Laccase-Mediator-System (LMS. The influence of the following main variables on the pulp physical properties were studied: enzyme dosage, reaction time, treatment temperature, and pH. Under the optimum conditions of laccase treatment – pH 5, temperature 50 °C, pulp consistency 4%, and a reaction time of 60 min – the optimum charge of laccase was 2u/g. It was also found that the tensile strength and tear indices of the pulps treated with laccase increased significantly. The two-stage method of enzyme-mild acidic hydrolysis was adopted to isolate lignin from the APMP pulps both before and after enzymatic treatments. The functional groups in all lignin samples were qualitatively and quantitatively analyzed with 31P-NMR spectra. The molecular weight distributions of all the lignin samples were obtained through Gel Permeation Chromatography (GPC after the lignin samples were benzoylated.

  20. Hydrogen peroxide mediates higher order chromatin degradation.

    Science.gov (United States)

    Bai, H; Konat, G W

    2003-01-01

    Although a large body of evidence supports a causative link between oxidative stress and neurodegeneration, the mechanisms are still elusive. We have recently demonstrated that hydrogen peroxide (H(2)O(2)), the major mediator of oxidative stress triggers higher order chromatin degradation (HOCD), i.e. excision of chromatin loops at the matrix attachment regions (MARs). The present study was designed to determine the specificity of H(2)O(2) in respect to HOCD induction. Rat glioma C6 cells were exposed to H(2)O(2) and other oxidants, and the fragmentation of genomic DNA was assessed by field inversion gel electrophoresis (FIGE). S1 digestion before FIGE was used to detect single strand fragmentation. The exposure of C6 cells to H(2)O(2) induced a rapid and extensive HOCD. Thus, within 30 min, total chromatin was single strandedly digested into 50 kb fragments. Evident HOCD was elicited by H(2)O(2) at concentrations as low as 5 micro M. HOCD was mostly reversible during 4-8h following the removal of H(2)O(2) from the medium indicating an efficient relegation of the chromatin fragments. No HOCD was induced by H(2)O(2) in isolated nuclei indicating that HOCD-endonuclease is activated indirectly by cytoplasmic signal pathways triggered by H(2)O(2). The exposure of cells to a synthetic peroxide, i.e. tert-butyrylhydroperoxide (tBH) also induced HOCD, but to a lesser extent than H(2)O(2). Contrary to the peroxides, the exposure of cells to equitoxic concentration of hypochlorite and spermine NONOate, a nitric oxide generator, failed to induce rapid HOCD. These results indicate that rapid HOCD is not a result of oxidative stress per se, but is rather triggered by signaling cascades initiated specifically by H(2)O(2). Furthermore, the rapid and extensive HOCD was observed in several rat and human cell lines challenged with H(2)O(2), indicating that the process is not restricted to glial cells, but rather represents a general response of cells to H(2)O(2). PMID:12421592

  1. Differentiation among peroxide explosives with an optoelectronic nose.

    Science.gov (United States)

    Li, Zheng; Bassett, Will P; Askim, Jon R; Suslick, Kenneth S

    2015-10-25

    Forensic identification of batches of homemade explosives (HME) poses a difficult analytical challenge. Differentiation among peroxide explosives is reported herein using a colorimetric sensor array and handheld scanner with a field-appropriate sampling protocol. Clear discrimination was demonstrated among twelve peroxide samples prepared from different reagents, with a classification accuracy >98%. PMID:26340082

  2. 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.

  3. Lipid peroxidation in ethanol poisoning: a critical reconsideration.

    Science.gov (United States)

    Dianzani, M U

    1985-01-01

    Evidence for the existence of increased lipid peroxidation in the liver after ethanol administration to rats is discussed. A criticism of the methods used to measure lipid peroxidation is also given. Most authors who are in favour of the presence of lipid peroxidation after ethanol have used the detection of thiobarbituric acid (TBA)-reacting substances as a measure of lipid peroxidation. This test is not entirely satisfactory, because: (1) it is not specific; (2) it mostly measures malonaldehyde, a substance of low toxicity, following a 1-2 hr incubation time; (3) several aldehydes produced during lipid peroxidation do not react with TBA. However, it is now clear that the aldehydes produced during lipid peroxidation are actively metabolized by homogenates, so differences in catabolism may influence the result of a TBA test. Measurement of the diene conjugation band, the other test usually used to detect lipid peroxidation, produces information only on the presence of dienes at a given moment, but does not give any information on the production or decomposition rates of such dienes. Thus differences in production or decomposition kinetics may mask the results. Notwithstanding these criticisms, most of the evidence at present is in favour of some involvement of lipid peroxidation in ethanol intoxication. One hypothesis is that of the direct impact of ethanol-derived free radicals. Another is that ethanol provokes the formation of oxygen free radical species, which can start lipid peroxidation either directly, or by exhausting anti-oxidant substances in the cell so as to change the balance in favour of increased peroxidation. Finally, a third hypothesis is that acetaldehyde, the main product of ethanol oxidation, is able to stimulate lipid peroxidation, possibly through the formation of free radicals, or depletion of levels of antioxidant substances. Experiments consisting of measuring total glutathione (GSH and GSSG) during lipid peroxidation stimulated by ethanol

  4. Determination of active oxygen content in rare earth peroxides

    International Nuclear Information System (INIS)

    The content of active oxygen in rare earth peroxides have been determined after the dissolution of the samples with hydrocloridic acid in the presence of potassium iodide. The free generated iodine is titrated with sodium thiosulfate using starch as indicator. The oxidation of iodide to the free iodine indicates the presence of a higher valence state rare earth oxide, until now specifically recognized for the oxides of cerium (Ce O2), praseodymium (Pr6 O11) and terbium (TB4 O7). recently the authors synthesized a new series of rare earth compounds, the peroxides. These new compounds were prepared by precipitating the rare earth elements complexed with carbonate ion by addition of hydrogen peroxide. the authors demonstrated that all rare earth elements, once solubilized by complexing with carbonate ion, are quantitatively precipitated as peroxide by addition of hydrogen peroxide. (author)

  5. Estimation of Lipid Peroxidation Induced by Hydrogen Peroxide in Cultured Human Lymphocytes

    OpenAIRE

    Siddique, Yasir Hasan; Ara, Gulshan; Afzal, Mohammad

    2011-01-01

    Malondialdehyde (MDA) is used for the estimation of damage by reactive oxygen species. MDA is a major reactive aldehyde resulting from the peroxidation of biological membranes. The most common method used to assess MDA production is the thiobarbituric acid (TBARS) assay. However, the value of this method is curbed by low specificity and has been criticized for its use in human studies. In the present study we have used an alternative method for the estimation of MDA production i.e. reaction o...

  6. 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.

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

    International Nuclear Information System (INIS)

    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/ft2) 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.

  8. At-home vital bleaching: a comparison of hydrogen peroxide and carbamide peroxide treatments.

    Science.gov (United States)

    Berga-Caballero, Amparo; Forner-Navarro, Leopoldo; Amengual-Lorenzo, José

    2006-01-01

    Tray bleaching of vital teeth performed at home by the patient under the dentist s supervision, whether alone or in combination with any of the in-office techniques, provides an interesting alternative to other methods employed in this type of dental treatment. This bleaching procedure applies low-concentration peroxides to the enamel by means of a custom-made mouth tray specifically designed for this purpose. The aim of this study is to examine and compare two commercially-available bleaching products, at equivalent concentrations, for use in this technique: VivaStyle (Vivadent) and FKD (Kin); the former is a 10% carbamide peroxide and the latter a 3.5% hydrogen peroxide formulation. It examines the parameters that must be monitored during the application of this type of procedure and presents 6 cases (3 treated with one of the above-mentioned products and the other 3 with the other), establishing the bleaching power of the products and the appearance and intensity of post-operatory hypersensitivity. The results obtained show that both products are effective for the purpose for which they were designed. In general, dental hypersensitivity was minimal. PMID:16388304

  9. 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.

  10. 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+ .

  11. Mixed-ligand chelate extraction of trivalent lanthanides and actinides with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 and dihexyl-n, n-diethylcarbamoylmethyl phosphonate

    International Nuclear Information System (INIS)

    Mixed-ligand chelate extraction of trivalent lanthanides such as La, Eu and Lu and a trivalent actinide, Am into xylene with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP) and dihexyl-N, N-diathylcarbamoylmethylphosphonate (CMP) has been studied by tracer techniques. These trivalent metal ions are found to be extracted from 0.01 mol/dm3 chloroacetate buffer solutions as M(PMBP)3 x HPMBP type self adducts with HPMBP alone and in the presence of CMP as M(PMBP)3 x CMP (where M= La, Eu, Lu and Am) into the organic phase. The equilibrium constants of the above species are deduced by non-linear regression analysis. The synergistic constants of trivalent lanthanides do not increase monotonically with atomic number but have a maximum at Eu and that of Am was found to lie between that of La and Eu. (author). 12 refs., 3 figs., 3 tabs

  12. 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

    2014-01-01

    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. 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.

  14. 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.

  15. 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

    2015-01-01

    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. PMID:26323635

  16. Inactivation of rabies virus by hydrogen peroxide.

    Science.gov (United States)

    Abd-Elghaffar, Asmaa A; Ali, Amal E; Boseila, Abeer A; Amin, Magdy A

    2016-02-01

    Development of safe and protective vaccines against infectious pathogens remains a challenge. Inactivation of rabies virus is a critical step in the production of vaccines and other research reagents. Beta-propiolactone (βPL); the currently used inactivating agent for rabies virus is expensive and proved to be carcinogenic in animals. This study aimed to investigate the ability of hydrogen peroxide (H2O2) to irreversibly inactivate rabies virus without affecting its antigenicity and immunogenicity in pursuit of finding safe, effective and inexpensive alternative inactivating agents. H2O2 3% rapidly inactivated a Vero cell adapted fixed rabies virus strain designated as FRV/K within 2h of exposure without affecting its antigenicity or immunogenicity. No residual infectious virus was detected and the H2O2-inactivated vaccine proved to be safe and effective when compared with the same virus harvest inactivated with the classical inactivating agent βPL. Mice immunized with H2O2-inactivated rabies virus produced sufficient level of antibodies and were protected when challenged with lethal CVS virus. These findings reinforce the idea that H2O2 can replace βPL as inactivating agent for rabies virus to reduce time and cost of inactivation process. PMID:26731189

  17. Spatial and temporal variations and factors controlling the concentrations of hydrogen peroxide and organic peroxides in rivers

    OpenAIRE

    Mostofa, Khan M. G.; Sakugawa, Hiroshi

    2009-01-01

    Hydrogen peroxide (H2O2) and organic peroxides (ROOH) were examined in water samples collected from the upstream and downstream sites of two Japanese rivers (the Kurose and the Ohta). H2O2 concentrations during monthly measurements varied between 6 and 213nM in the Kurose River and 33 and 188nM in the Ohta River. ROOH varied between 0 and 73nM in the Kurose River and 1 and 80nM in the Ohta. Concentrations of peroxides were higher during the summer months than in winter. H2O2 concentrations co...

  18. Apparatus for the continuous precipitation of uranium peroxide

    International Nuclear Information System (INIS)

    A process and apparatus are described for the production of pourable, directly compactable uranium dioxide powder by continuous precipitation of uranium peroxide from a stirred uranyl nitrate solution at a pH of 1-2.5 with hydrogen peroxide, calcining of the peroxide at 5000-8000C. And subsequent reduction at 5500-7500C. Precipitation solution contains 70-150 g/l of uranium and 0.80 g/l of ammonium nitrate and is treated with 15-20% aqueous hydrogen peroxide solution in the ratio of U:H2O2 from 1:1.5 to 1:3 and there is led through the solution a mixture of ammoni and air having an air-ammonia volume ratio of 1:0.3-0.6

  19. Quantifying intracellular hydrogen peroxide perturbations in terms of concentration

    Directory of Open Access Journals (Sweden)

    Beijing K. Huang

    2014-01-01

    Full Text Available Molecular level, mechanistic understanding of the roles of reactive oxygen species (ROS in a variety of pathological conditions is hindered by the difficulties associated with determining the concentration of various ROS species. Here, we present an approach that converts fold-change in the signal from an intracellular sensor of hydrogen peroxide into changes in absolute concentration. The method uses extracellular additions of peroxide and an improved biochemical measurement of the gradient between extracellular and intracellular peroxide concentrations to calibrate the intracellular sensor. By measuring peroxiredoxin activity, we found that this gradient is 650-fold rather than the 7–10-fold that is widely cited. The resulting calibration is important for understanding the mass-action kinetics of complex networks of redox reactions, and it enables meaningful characterization and comparison of outputs from endogenous peroxide generating tools and therapeutics across studies.

  20. 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...

  1. Atmospheric hydrogen peroxide and methyl hydroperoxide in Yanbian, China

    Science.gov (United States)

    Kim, Y.; Ji, B.; Lee, M.; Kim, K.; Lee, G.

    2003-04-01

    Hydrogen peroxide and organic peroxides are photochemical byproducts. They are referred as the indicator of oxidizing capacity of the atmosphere. Further, they are related with the production and removal of ozone in photochemistry. To better understand the photochemical processes in the troposphere, it is essential to know the correct concentration of hydroperoxides. Hydrogen peroxide and methyl Hydroperoxide were measured from 24 Aug to 3 Sep in Yanbian, China. Measurements were made for continuously during the whole course of the experiments. After collected in aqueous solution using continuous scrubbing coil, hydroperoxides were separated by HPLC, and then quantified by fluorescence produced using postcolumn enzyme derivatization. Collection and analysis were done automatically Average concentration of hydrogen peroxide and methyl hydroperoxide were 0.9ppbc and 1.6 ppb, respectively. In general, hydroperoxides showed typical diurnal variations with the maximum concentration during day. It was the first study of air pollution conducted in Yanbian, China. Detailed results will be presented in the meeting.

  2. Quantum chemistry research structure and electronic properties of peroxides

    OpenAIRE

    Grytselyak, Tymofiy; Shchodryi, Volodymyr; Dutka, Volodymyr; Kovalskyi, Yaroslav

    2013-01-01

    We have calculated the optimal structure, electronic properties and heat of formation (?fH? ) peroxide compounds with the help of semiempirical quantum chemical methods. Theoretically calculated values well coincide with the values found from thermochemical experiments.

  3. 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...

  4. 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.

  5. Hydrogen peroxide- metals- chelating agents; interactions and analytical techniques

    OpenAIRE

    Rämö, J.

    2003-01-01

    Abstract Information about interactions among metals, hydrogen peroxide and chelating agents is needed to develop environmental technology and the operating efficiency of modern elemental chlorine free and total chlorine free bleaching processes. The work presented here focused on the properties of metal chelates and corrosion of titanium in an alkaline hydrogen peroxide solution. A comparative study between three rapid analysis methods, ICP-AES, XRF and ISE, was performed in pulp matrix a...

  6. Selective electrochemical generation of hydrogen peroxide from water oxidation

    OpenAIRE

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; 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 requir...

  7. Graphene-based materials in catalytic wet peroxide oxidation

    OpenAIRE

    Gomes, Helder; Ribeiro, Rui; Pastrana-Martínez, Luisa; Figueiredo, José; Faria, Joaquim; Silva, Adrián

    2014-01-01

    In catalytic wet peroxide oxidation (CWPO),an advanced oxidation process, hydrogen peroxide (H2O2) is decomposed catalytically giving rise to hydroxyl radicals (HO•).These radicals, exhibiting high oxidizing potential, serve as effective and non selective species for the degradation of several organic pollutants in liquid phase. Since the report of Lücking et al. [1], carbon materials have been explored as catalysts for CWPO[2]. Recent reports address process intensification issues, br...

  8. Natural manganese deposits as catalyst for decomposing hydrogen peroxide

    OpenAIRE

    Knol, A.H.; K. Lekkerkerker-Teunissen; Van Dijk, J. C.

    2015-01-01

    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-...

  9. 1,3-Dimethyl-5-(3,4,5-tris(alkoxy)benzoyl) barbituric acid derivatives and their liquid crystalline difluoroboron complexes: Synthesis, characterization and comparative investigations of mesomorphic, thermotropic and thermo-morphologic properties

    Science.gov (United States)

    Giziroglu, Emrah; Nesrullajev, Arif; Orhan, Nil

    2014-01-01

    A series of 1,3-dimethyl-5-(3,4,5-tris(alkoxy)benzoyl) barbituric acid derivatives 1a-4a with various chain length were synthesized by our group for the first time through the addition of 1,3-dimethyl barbituric acid to 3,4,5-tris(alkoxy)benzoyl chloride at room temperature in presence of pyridine. For preparation of their difluoroboron complexes, the derivatives 1a-4a reacts with borontrifluoride in the presence of triethylamine affording 1b-4b in moderate yields. All derivatives and complexes have been fully characterized by MS, FT-IR and multinuclear NMR spectroscopy. We also explored their liquid crystal properties by using POM, OM, CTW and DSC techniques. The results show that 3b and 4b with longer alkyl chain are monomorphic mesogens and exhibited enantiotropic thermotropic liquid crystalline mesophases. Investigation of their mesomorphic, thermo-morphologic and thermotropic properties is presented in this work.

  10. 49 CFR 173.225 - Packaging requirements and other provisions for organic peroxides.

    Science.gov (United States)

    2010-10-01

    ... require temperature control are subject to the provisions of § 173.21(f). When an IBC or bulk packaging is... that is not identified by technical name in the Organic Peroxides Table, Organic Peroxide IBC Table, or...) Organic Peroxide IBC Table. The following Organic Peroxide IBC Table specifies, by technical name,...

  11. Peroxide test strips detect added hydrogen peroxide in raw milk at levels affecting bacterial load.

    Science.gov (United States)

    Martin, Nicole H; Friedlander, Adam; Mok, Allen; Kent, David; Wiedmann, Martin; Boor, Kathryn J

    2014-10-01

    Hydrogen peroxide (H2O2) has a long-established history of use as a preservative in milk worldwide. The use of H2O2 to activate the inherent lactoperoxidase enzyme system has dramatically improved the quality of raw dairy products in areas in which cooling is not widely available. In the United States, however, where refrigeration is widely available, the addition of H2O2 to milk is not permitted, with the exception of certain applications prior to cheesemaking and during the preparation of modified whey. Due to the relatively quick deterioration of H2O2 in fluid milk, the detection of raw milk adulterated with the compound can be challenging. In this study we evaluated (i) total aerobic bacterial counts and (ii) ability of peroxide test strips to detect H2O2 in raw milk with various concentrations (0, 100, 300, 500, 700, and 900 ppm) of added H2O2, incubated at both 6 and 21°C for 0, 24, and 48 h. Results showed that at both 6 and 21°C the H2O2 concentration and time had a significant effect on bacterial loads in raw milk. Additionally, commercially available test strips were able to detect H2O2 in raw milk, with predicted probability of >90%, immediately after addition and after 24 and 48 h for the higher concentrations used, offering a viable method for detecting raw milk adulteration with H2O2. PMID:25285503

  12. Localised hydrogen peroxide sensing for reproductive health

    Science.gov (United States)

    Purdey, Malcolm S.; Schartner, Erik P.; Sutton-McDowall, Melanie L.; Ritter, Lesley J.; Thompson, Jeremy G.; Monro, Tanya M.; Abell, Andrew D.

    2015-05-01

    The production of reactive oxygen species (ROS) is known to affect the developmental competence of embryos. Hydrogen peroxide (H2O2) an important reactive oxygen species, is also known to causes DNA damage and defective sperm function. Current techniques require incubating a developing embryo with an organic fluorophore which is potentially hazardous for the embryo. What we need is a localised ROS sensor which does not require fluorophores in solution and hence will allow continuous monitoring of H2O2 production without adversely affect the development of the embryo. Here we report studies on such a fibre-based sensor for the detection of H2O2 that uses a surface-bound aryl boronate fluorophore carboxyperoxyfluor-1(CPF1). Optical fibres present a unique platform due to desirable characteristics as dip sensors in biological solutions. Attempts to functionalise the fibre tips using polyelectrolyte layers and (3-aminopropyl)triethoxysilane (APTES) coatings resulted in a limited signal and poor fluorescent response to H2O2 due to a low tip surface density of the fluorophore. To increase the surface density, CPF1 was integrated into a polymer matrix formed on the fibre tip by a UV-catalysed polymerisation process of acrylamide onto a methacrylate silane layer. The polyacrylamide containing CPF1 gave a much higher surface density than previous surface attachment methods and the sensor was found to effectively detect H2O2. Using this method, biologically relevant concentrations of H2O2 were detected, enabling remote sensing studies into ROS releases from embryos throughout early development.

  13. Alkaline peroxide processing of low-enriched uranium targets for 99Mo production -- Decomposition of hydrogen peroxide

    International Nuclear Information System (INIS)

    The recent progress on the alkaline peroxide processing of low-enriched uranium targets for the production of 99Mo, a parent nuclide of the widely used medical isotope 99mTc, is reported. Kinetic studies were undertaken to investigate the decomposition of hydrogen peroxide in alkaline solution in contact with a uranium metal surface. It was found that the decomposition of hydrogen peroxide essentially follows the kinetic trend of uranium dissolution and can be classified into two regimes, depending on the hydroxide concentration. In the low-base regime (0.2 M), the rate of peroxide decomposition is independent of alkali concentration. When the acid/base equilibrium between H2O2 and O2H- is taken into account, the overall rate of hydrogen peroxide disappearance can be described as a 0.25th order reaction with respect to hydrogen peroxide concentration over NaOH concentrations ranging from 0.01 to 5 M. Empirical kinetics models are proposed and discussed

  14. Structure-Toxicity Relations of Some Substituted 2-BENZOYL-1H-INDENE-1,3(2H)-DIONE Rodenticides.

    Science.gov (United States)

    Opong-Mensah, Kofi

    Chemical control of rodents depends primarily on the use of poisoned baits. The need for more potent rodenticides arises out of the evolution of resistant strains in rodent populations. One novel and 5 known benzoylindandiones were synthesized by condensation of methyl aryl ketones with dimethyl phthalate. Novel TLC, HPLC, and GC methods were developed to assay the acylindandiones after characterization by MS, IR and FT-NMR spectroscopy. The n-octanol/water partition coefficient (log P), acid dissociation constants (pKa) and mouse LD(,50)s were determined experimentally. Quantum mechanical molecular descriptors, such as HOMO-LUMO energies, were generated using computer models. The structure-toxicity relations of the benzoylindandiones were developed using regression models and partial least squares analysis. LD(,50)s (mM/Kg) for male Sprague-Dawley mice by intraperitoneal injection for 2-benzoyl-1,3-indandione (1), 2-(4'-methoxybenzoyl)-1,3-indandione (2), 2-(3'-methylbenzoyl) -1,3-indandione (3), 2-(4'-methylbenzoyl)-1,3-indandione (4), 2-(4'-isopropylbenzoyl)-1,3-indandione (5), and 2 -diphenylacetyl-1,3-indandione (6) were (median, 95% confidence limits): 1, 0.038 (0.030-0.049); 2, 0.026 (0.021-0.037); 3, 0.083 (0.065-0.106); 4, 0.077 (0.060-0.098); 5, 0.096 (0.071-0.128); and 6, 0.048 (0.035-0.064); log P was (mean (+OR-) standard error): 1, 1.14 (+OR-) 0.03; 2, 1.37 (+OR -) 0.02; 3, 1.24 (+OR-) 0.04; 4, 1.31 (+OR-) 0.02; 5, 1.43 (+OR-) 0.03 and 6, 2.47 (+OR-) 0.03; the pKas were (mean (+OR-) standard error): 1, 3.08 (+OR-) 0.02; 2, 3.91 (+OR -) 0.01; 3, 2.63 (+OR-) 0.01; 4, 2.93 (+OR-) 0.02; 5, 3.91 (+OR-) 0.01; and 6, 3.31 (+OR-) 0.01. -Log (,10)LD(,50) of the 6 indandiones correlated highly with the mean of the C-13 NMR chemical shifts of the carbonyl carbons, but poorly with pKa, IR carbonyl stretching frequencies, HOMO, LUMO, Hammett sigma and log P. 2-Benzoyl-1,3-indandione and 2-(4'-methoxybenzoyl) -1,3-indandione were more potent rodenticides than

  15. Different Modes of Hydrogen Peroxide Action During Seed Germination

    Science.gov (United States)

    Wojtyla, Łukasz; Lechowska, Katarzyna; Kubala, Szymon; Garnczarska, Małgorzata

    2016-01-01

    Hydrogen peroxide was initially recognized as a toxic molecule that causes damage at different levels of cell organization and thus losses in cell viability. From the 1990s, the role of hydrogen peroxide as a signaling molecule in plants has also been discussed. The beneficial role of H2O2 as a central hub integrating signaling network in response to biotic and abiotic stress and during developmental processes is now well established. Seed germination is the most pivotal phase of the plant life cycle, affecting plant growth and productivity. The function of hydrogen peroxide in seed germination and seed aging has been illustrated in numerous studies; however, the exact role of this molecule remains unknown. This review evaluates evidence that shows that H2O2 functions as a signaling molecule in seed physiology in accordance with the known biology and biochemistry of H2O2. The importance of crosstalk between hydrogen peroxide and a number of signaling molecules, including plant phytohormones such as abscisic acid, gibberellins, and ethylene, and reactive molecules such as nitric oxide and hydrogen sulfide acting on cell communication and signaling during seed germination, is highlighted. The current study also focuses on the detrimental effects of H2O2 on seed biology, i.e., seed aging that leads to a loss of germination efficiency. The dual nature of hydrogen peroxide as a toxic molecule on one hand and as a signal molecule on the other is made possible through the precise spatial and temporal control of its production and degradation. Levels of hydrogen peroxide in germinating seeds and young seedlings can be modulated via pre-sowing seed priming/conditioning. This rather simple method is shown to be a valuable tool for improving seed quality and for enhancing seed stress tolerance during post-priming germination. In this review, we outline how seed priming/conditioning affects the integrative role of hydrogen peroxide in seed germination and aging. PMID:26870076

  16. Lipid Peroxidation: Pathophysiology and Pharmacological Implications in the Eye

    Directory of Open Access Journals (Sweden)

    Ya Fatou eNjie-Mbye

    2013-12-01

    Full Text Available Oxygen-derived free radicals such as hydroxyl and hydroperoxyl species have been shown to oxidize phospholipids and other membrane lipid components leading to lipid peroxidation. In the eye, lipid peroxidation has been reported to play an important role in degenerative ocular diseases (age-related macular degeneration, cataract, glaucoma, diabetic retinopathy. Indeed, ocular tissues are prone to damage from reactive oxygen species due to stress from constant exposure of the eye to sunlight, atmospheric oxygen and environmental chemicals. Furthermore, free radical catalyzed peroxidation of long chain polyunsaturated acids (LCPUFAs such as arachidonic acid and docosahexaenoic acid leads to generation of LCPUFA metabolites including isoprostanes and neuroprostanes that may further exert pharmacological/toxicological actions in ocular tissues. Evidence from literature supports the presence of endogenous defense mechanisms against reactive oxygen species in the eye, thereby presenting new avenues for the prevention and treatment of ocular degeneration. Hydrogen peroxide (H2O2 and synthetic peroxides can exert pharmacological and toxicological effects on tissues of the anterior uvea of several mammalian species. There is evidence suggesting that the retina, especially retinal ganglion cells can exhibit unique characteristics of antioxidant defense mechanisms. In the posterior segment of the eye, H2O2 and synthetic peroxides produce an inhibitory action on glutamate release (using [3H]-D-aspartate as a marker, in vitro and on the endogenous glutamate and glycine concentrations in vivo. In addition to peroxides, isoprostanes can elicit both excitatory and inhibitory effects on norepinephrine (NE release from sympathetic nerves in isolated mammalian iris ciliary bodies. Whereas isoprostanes attenuate dopamine release from mammalian neural retina, in vitro, these novel arachidonic acid metabolites exhibit a biphasic regulatory effect on glutamate release

  17. 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

  18. Sensitive quantitation of polyamines in plant foods by ultrasound-assisted benzoylation and dispersive liquid-liquid microextraction with the aid of experimental designs.

    Science.gov (United States)

    Pinto, Edgar; Melo, Armindo; Ferreira, Isabel M P L V O

    2014-05-14

    A new method involving ultrasound-assisted benzoylation and dispersive liquid-liquid microextraction was optimized with the aid of chemometrics for the extraction, cleanup, and determination of polyamines in plant foods. Putrescine, cadaverine, spermidine, and spermine were derivatized with 3,5-dinitrobenzoyl chloride and extracted by dispersive liquid-liquid microextraction using acetonitrile and carbon tetrachloride as dispersive and extraction solvents, respectively. Two-level full factorial design and central composite design were applied to select the most appropriate derivatization and extraction conditions. The developed method was linear in the 0.5-10.0 mg/L range, with a R(2) ≥ 0.9989. Intra- and interday precisions ranged from 0.8 to 6.9% and from 3.0 to 10.3%, respectively, and the limit of detection ranged between 0.018 and 0.042 μg/g of fresh weight. This method was applied to the analyses of six different types of plant foods, presenting recoveries between 81.7 and 114.2%. The method is inexpensive, versatile, simple, and sensitive. PMID:24773181

  19. Determination of rhenium content in molybdenite by ICP-MS after separation of the major matrix by solvent extraction with N-benzoyl-N-phenylhydroxalamine.

    Science.gov (United States)

    Li, Jie; Zhong, Li-feng; Tu, Xiang-lin; Liang, Xi-rong; Xu, Ji-feng

    2010-05-15

    A simple and rapid analytical method for determining the concentration of rhenium in molybdenite for Re-Os dating was developed. The method used isotope dilution-inductively coupled plasma-mass spectrometry (ID-ICP-MS) after the removal of major matrix elements (e.g., Mo, Fe, and W) from Re by solvent extraction with N-benzoyl-N-phenylhydroxylamine (BPHA) in chloroform solution. The effect on extraction efficiency of parameters such as pH (HCl concentration), BPHA concentration, and extraction time were also assessed. Under the optimal experimental conditions, the validity of the separation method was accessed by measuring (187)Re/(185)Re values for a molybdenite reference material (JDC). The obtained values were in good agreement with previously measured values of the Re standard. The proposed method was applied to replicate Re-Os dating of JDC and seven samples of molybdenite from the Yuanzhuding large Cu-Mo porphyry deposit. The results demonstrate good precision and accuracy for the proposed method. The advantages of the method (i.e., simplicity, efficiency, short analysis time, and low cost) make it suitable for routine analysis. PMID:20298878

  20. Synergistic solvent extraction of trivalent lanthanides and actinide by mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 and neutral oxo-donors

    International Nuclear Information System (INIS)

    The synergistic solvent extraction of trivalent lanthanides such as La, Eu and Lu and a trivalent actinide, Am, has been studied with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 (HPMBP) and bis(2-ethylhexyl) sulphoxide (B2EHSO) or octyl (phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in xylene. The extraction data have been analysed by both graphical and theoretical methods by taking into account aqueous phase speciation and all plausible complexes extracted into the organic phase. With HPMBP alone all the trivalent metal ions form M(PMBP)3 - HPMBP type self adducts. With B2EHSO as a neutral donor, the synergistic adduct species are M(PMBP)3 - B2EHSO and M(PMBP)3 - 2 B2EHSO (where M = La, Eu, Lu and Am), whereas with CMPO as a neutral donor the only complex extracted into the organic phase is M(PMBP)3 - CMPO. The synergistic extraction constants of the above species which were deduced by non-linear regression analysis are found to increase monotonically with decreasing ionic radii of these metal ions. 27 refs., 5 figs., 4 tabs

  1. Enhanced solubility and antibacterial activity of lipophilic fluoro-substituted N-benzoyl-2-aminobenzothiazoles by complexation with β-cyclodextrins.

    Science.gov (United States)

    Trapani, A; De Laurentis, N; Armenise, D; Carrieri, A; Defrenza, I; Rosato, A; Mandracchia, D; Tripodo, G; Salomone, A; Capriati, V; Franchini, C; Corbo, F

    2016-01-30

    Some lipophilic fluoro-substituted N-benzoyl-2-aminobenzothiazole antibacterial agents have been evaluated for their activity in the presence of cyclodextrins (CDs) containing aqueous solutions where CDs are adopted as solubilizing excipients for improving the poor water solubility of these compounds. For such purpose both the natural β-CD and one of FDA/EMA approved CDs for parenteral use (i.e. HP-β-CD) have been employed. The solubility rank order observed was accounted for by thermal analysis (Differential Scanning Calorimetry) and FT-IR spectroscopy. The most promising compound was subjected to further NMR spectroscopic studies and molecular modelling simulations to verify the interactions between the guest molecule and the CD cavity. The assessment of the antibacterial activity of such compounds against selected Gram positive and Gram negative bacterial strains clearly showed that their antimicrobial effectiveness may, quite in all instances, be positively affected by complexation with β-CD and HP-β-CD. These results, which are in some ways in contrast with those already reported in the literature, are herein discussed on the basis of plausible mechanisms. Moreover, this investigation also reveals that the described methodology of complexing both lipophilic and hydrophilic antimicrobial agents with CDs may be an useful approach to enhance their effectiveness as well as a promising strategy to overcome even the microbial resistance problem. PMID:26611670

  2. 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.

  3. Synthesis and Crystal Structure of a Manganese(Ⅱ) Complex with 2-(4'-Chlorine-benzoyl)-benzoic Acid and 1,10-Phenanthroline

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-Wei; LI Xiu-Mei; MENG Qing-Long; LIU Bo; GAO Guang-Gang

    2009-01-01

    A new metal-organic complex Mn2(cbba)4(phen)2 (Hcbba = 2-(4'-chlorine-benzoyl)-benzoic acid, phen = 1,10-phenanthroline) 1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses and IR spectroscopy. The compound crystallizes in orthorhombic, space group Pbcn with a = 12.154(5), b = 18.166(7), c =31.197(13) (A°), V = 6887(5) (A°)3, C80H48C14Mn2N4O12, Mr= 1508.90, Dc = 1.455 g/cm3, μ(MoKa) =0.591 mm-1, F(000) = 3080, Z = 4, the final R = 0.0408 and wR = 0.0873 for 4033 observed reflections (I > 2σ(I)). In the crystal structure, the manganese atom is six-coordinated with four carboxylate oxygen atoms from three different cbba ligands and two nitrogen atoms from phen ligands, showing a distorted octahedral geometry. Furthermore, it exhibits a 3D supramolecular network through π-π interactions.

  4. The Melting Behavior and Thermal Stability of Green Poly(L-lactic acid) with N, N, N, N'-Tetra(benzoyl) Ethylene Diamine Tetraacetic Acid Dihydrazide

    International Nuclear Information System (INIS)

    The thermal properties of green poly(L-lactic acid) (PLLA) with N, N, N, N'-tetra(benzoyl) ethylene diamine tetraacetic acid dihydrazide (NA) at different conditions were investigated. The melting behavior of PLLA/NA sample after isothermal crystallization at 100 degree C showed that the low-temperature melting peak shifted to high temperature with increasing of crystallization time. However, the high-temperature melting peak did not show any change. Meantime, the melting enthalpy of cold crystallization was higher than that of hot crystallization, and the difference between cold crystallization and hot crystallization increased from 0.31 J/g to 0.89 J/g with increasing of crystallization time. Heating or cooling rate affected the melting behavior of PLLA, the low-temperature and high-temperature melting peak shifted to low temperature with increasing of rate, and the ratio of melting peak area between low-temperature melting peak and high-temperature melting peak decreased. Thermal stability of PLLA/NA indicated that PLLA/NA only exhibited one decomposition stage as decomposition of PLLA. (author)

  5. 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.

  6. Improvement of adventitious root formation in flax using hydrogen peroxide.

    Science.gov (United States)

    Takáč, Tomáš; Obert, Bohuš; Rolčík, Jakub; Šamaj, Jozef

    2016-09-25

    Flax (Linum usitatissimum L.) is an important crop for the production of oil and fiber. In vitro manipulations of flax are used for genetic improvement and breeding while improvements in adventitious root formation are important for biotechnological programs focused on regeneration and vegetative propagation of genetically valuable plant material. Additionally, flax hypocotyl segments possess outstanding morphogenetic capacity, thus providing a useful model for the investigation of flax developmental processes. Here, we investigated the crosstalk between hydrogen peroxide and auxin with respect to reprogramming flax hypocotyl cells for root morphogenetic development. Exogenous auxin induced the robust formation of adventitious roots from flax hypocotyl segments while the addition of hydrogen peroxide further enhanced this process. The levels of endogenous auxin (indole-3-acetic acid; IAA) were positively correlated with increased root formation in response to exogenous auxin (1-Naphthaleneacetic acid; NAA). Histochemical staining of the hypocotyl segments revealed that hydrogen peroxide and peroxidase, but not superoxide, were positively correlated with root formation. Measurements of antioxidant enzyme activities showed that endogenous levels of hydrogen peroxide were controlled by peroxidases during root formation from hypocotyl segments. In conclusion, hydrogen peroxide positively affected flax adventitious root formation by regulating the endogenous auxin levels. Consequently, this agent can be applied to increase flax regeneration capacity for biotechnological purposes such as improved plant rooting. PMID:26921706

  7. Erythrocyte susceptibility to lipid peroxidation in patients with coronary atherosclerosis.

    Directory of Open Access Journals (Sweden)

    Dincer,Yildiz

    1999-12-01

    Full Text Available In recent years it has been reported that free oxygen radicals play an important role in the pathogenesis of degenerative diseases and that antioxidant vitamins such as vitamins E or C prevent their harmful effects. In this study, we evaluated the following: Erythrocyte susceptibility to lipid peroxidation; the role of erythrocyte glutathione (GSH as an antioxidant; plasma lipid fractions; and the relationship between plasma lipid peroxides and antioxidant vitamin levels. Thiobarbituric acid-reactive substance (TBARS levels were measured to determine the levels of plasma lipid peroxides and the susceptibility to lipid peroxidation when erythrocytes were stressed by hydrogen peroxide for 2 h in vitro. Erythrocyte TBARS production was significantly higher in patients with coronary atherosclerosis than in the controls. On the other hand, the levels of plasma high-density lipoproteins, vitamin C, vitamin E and erythrocyte GSH were significantly lower, and the levels of plasma total cholesterol, triglycerides, low-density lipoproteins and TBARS were significantly higher in the patients with coronary atherosclerosis than in the controls. In conclusion, our results indicate that erythrocytes from patients with coronary atherosclerosis are more susceptible to oxidation than those of controls and that these patients have lowered antioxidant capacity as revealed by decreased plasma levels of vitamins C and E.

  8. 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.

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

    International Nuclear Information System (INIS)

    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

  10. Aluminum induces lipid peroxidation and aggregation of human blood platelets

    Directory of Open Access Journals (Sweden)

    Neiva T.J.C.

    1997-01-01

    Full Text Available Aluminum (Al3+ intoxication is thought to play a major role in the development of Alzheimer's disease and in certain pathologic manifestations arising from long-term hemodialysis. Although the metal does not present redox capacity, it can stimulate tissue lipid peroxidation in animal models. Furthermore, in vitro studies have revealed that the fluoroaluminate complex induces diacylglycerol formation, 43-kDa protein phosphorylation and aggregation. Based on these observations, we postulated that Al3+-induced blood platelet aggregation was mediated by lipid peroxidation. Using chemiluminescence (CL of luminol as an index of total lipid peroxidation capacity, we established a correlation between lipid peroxidation capacity and platelet aggregation. Al3+ (20-100 µM stimulated CL production by human blood platelets as well as their aggregation. Incubation of the platelets with the antioxidants nor-dihydroguaiaretic acid (NDGA (100 µM and n-propyl gallate (NPG (100 µM, inhibitors of the lipoxygenase pathway, completely prevented CL and platelet aggregation. Acetyl salicylic acid (ASA (100 µM, an inhibitor of the cyclooxygenase pathway, was a weaker inhibitor of both events. These findings suggest that Al3+ stimulates lipid peroxidation and the lipoxygenase pathway in human blood platelets thereby causing their aggregation

  11. 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.

  12. 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.

  13. Electrochemical behaviour of platinum in hydrogen peroxide solution (1963)

    International Nuclear Information System (INIS)

    The relative stability of hydrogen peroxide in aqueous solution at 25 deg. C, allows its amperometric determination from the theory, using either its cathodic reduction or its anodic oxidation. The cathodic reduction yields a wave on a platinum electrode only when some oxygen is present in the solution. It cannot, therefore, be used for electrochemical determination. On the other hand, the anodic oxidation on platinum produces a wave which might be used. However, a passivation of platinum occurs at the same time. This passivation process is studied by means of potentio-kinetic, potentio-static, intensio-static curves and of pH measurements in the vicinity of the anode. A mechanism for passivation is presented, which takes into account the role of hydrogen peroxide as a reducing agent. This passivation rules out any analytical application of the oxidation reaction of hydrogen peroxide. (author)

  14. Modeling the oxidation of phenolic compounds by hydrogen peroxide photolysis.

    Science.gov (United States)

    Zhang, Tianqi; Cheng, Long; Ma, Lin; Meng, Fanchao; Arnold, Robert G; Sáez, A Eduardo

    2016-10-01

    Hydrogen peroxide UV photolysis is among the most widely used advanced oxidation processes (AOPs) for the destruction of trace organics in waters destined for reuse. Previous kinetic models of hydrogen peroxide photolysis focus on the dynamics of hydroxyl radical production and consumption, as well as the reaction of the target organic with hydroxyl radicals. However, the rate of target destruction may also be affected by radical scavenging by reaction products. In this work, we build a predictive kinetic model for the destruction of p-cresol by hydrogen peroxide photolysis based on a complete reaction mechanism that includes reactions of intermediates with hydroxyl radicals. The results show that development of a predictive kinetic model to evaluate process performance requires consideration of the complete reaction mechanism, including reactions of intermediates with hydroxyl radicals. PMID:27448315

  15. 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)

  16. Carbonate leaching of uranium and hydrogen peroxide stabilizer therefor

    International Nuclear Information System (INIS)

    In the carbonate leaching process for the solution mining of subterranean uranium containing formations in which an injection well is drilled and completed within the uranium formation; alkaline carbonate uranium leaching solution and sufficient hydrogen peroxide are injected through the injection wells into the formation whereby uranium values are produced from production wells, characterized by providing in the leaching solution a mixture of 1-hydroxyethylidene-1,1-diphosphonic acid and an alkali metal pyrophosphate in a weight ratio of from 1 to 10 to 10 to 1, the amount of said mixture being sufficient to inhibit decomposition of the hydrogen peroxide in said leaching solution

  17. Formation of hydrogen peroxide through ozonolysis of alkenes

    Energy Technology Data Exchange (ETDEWEB)

    Bechara, J.; Becker, K.H. (Wuppertal Univ. (Gesamthochschule) (DE)); Brockmann, K.J.

    1991-07-01

    The gas phase reactions of ozone with several alkenes (including isoprene and some terpenes) are investigated for the formation of hydrogen peroxide (H202) under atmospheric conditions by means of a TDLAS. All alkenes produced hydrogen peroxide with a molar yield in the part per thousand range. Water vapour induced a significant increase (factor 3 to 14) in H202 yield, due to the reaction of water vapour with the Criegee biradical, the main intermediate in alkene ozonolysis. Reaction rate are reported, with respect to sulfur dioxide, for ethene, tetramethylethene and limonene. Forest air application is discussed.

  18. MOLYBDENUM CATALYZED ACID PEROXIDE BLEACHING OF EUCALYPTUS KRAFT PULP

    OpenAIRE

    Marcos S. Rabelo; Jorge L. Colodette; Vera M. Sacon; Marcelo R. Silva; Marco A. B. Azevedo

    2008-01-01

    Molybdenum catalyzed peroxide bleaching (PMo Stage) consists of pulp treatment with hydrogen peroxide under acidic conditions in the presence of a molybdenum catalyst. Molybdenum is applied in catalytic doses (50-200 mg/kg pulp) and may originate from various sources, including (NH4)6Mo7O24.4H2O, Na2MoO4.2H2O, siliconmolybdate, etc. This work is aimed at optimizing the PMo stage and evaluating its industrial application in the OAZDP sequence. Optimum PMo stage conditions for bleaching eucalyp...

  19. Hydrogen Peroxide Gas Generator Cycle with a Reciprocating Pump

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J C

    2002-06-11

    A four-chamber piston pump is powered by decomposed 85% hydrogen peroxide. The performance envelope of the evolving 400 gram pump has been expanded to 172 cc/s water flow at discharge pressures near 5 MPa. A gas generator cycle system using the pump has been tested under similar conditions of pressure and flow. The powerhead gas is derived from a small fraction of the pumped hydrogen peroxide, and the system starts from tank pressures as low as 0.2 MPa. The effects of steam condensation on performance have been evaluated.

  20. 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

  1. On the transferability of atomic contributions to the optical rotatory power of hydrogen peroxide, methyl hydroperoxide and dimethyl peroxide

    DEFF Research Database (Denmark)

    Sánchez, Marina; Alkorta, Ibon; Elguero, José;

    2014-01-01

    partitioned into atomic and group contributions. In the present work, we investigate the transferability of such individual contributions in a series of small, chiral molecules: hydrogen peroxide, methyl hydroperoxide and dimethyl peroxide. The isotropic atomic or group contributions have been evaluated for...... the hydrogen, oxygen and carbon atoms as well as for the methyl group at the level of time-dependent density functional theory with the B3LYP exchange-correlation functional employing a large Gaussian basis set. We find that the atomic or group contributions are not transferable among these three...

  2. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...

  3. A PORTABLE MICROREACTOR SYSTEM TO SYNTHESIZE HYDROGEN PEROXIDE - PHASE I

    Science.gov (United States)

    In the event that vehicles of buildings become contaminated by hazardous chemical or biological materials, a well-studied and effective decontaminant is hydrogen peroxide vapor (HPV).  Unfortunately, the current technology for generating HPV requires 35 weight percent hydro...

  4. 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.

  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. 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.

  7. Peroxidative damage of mitochondrial respiration is substrate-dependent

    Czech Academy of Sciences Publication Activity Database

    Endlicher, R.; Křiváková, P.; Rauchová, Hana; Nůsková, Hana; Červinková, Z.; Drahota, Zdeněk

    2009-01-01

    Roč. 58, č. 5 (2009), s. 685-692. ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA303/06/1261 Institutional research plan: CEZ:AV0Z50110509 Keywords : mitochondrial enzymes * peroxidative damage * tert-butyl hydroperoxide Subject RIV: CE - Biochemistry Impact factor: 1.430, year: 2009

  8. Lipid peroxidation products in plasma of patients with chronic pancreatitis

    Czech Academy of Sciences Publication Activity Database

    Podborská, Martina; Lojek, Antonín; Kubala, Lukáš; Buňková, Radka; Márová, I.; Ševčíková, A.; Trna, J.; Dítě, P.

    2011. Roč. 102, - (2008), s751-s752. ISSN 1803-2389. [4th Meeting on Chemistry and Life. 09.09.2008-11.09.2008, Brno] Institutional research plan: CEZ:AV0Z5004920; CEZ:AV0Z50040702 Keywords : chronic pancreatitis * lipid peroxidation * HPLC Subject RIV: BO - Biophysics

  9. New acetogenin peroxides from the Indian sponge Acarnus bicladotylota

    Digital Repository Service at National Institute of Oceanography (India)

    Fontana, A.; d; DeSouza, L.; Mollo, E.; Parameswaran, P.S.; Cimino, G.

    Two new cyclic peroxides (1 and 2) and the known metabolite 3 have been found in the organic extract of the Indian sponge Acarnus bicladotylota. The structure of the new products has been assured by chemical and spectroscopic methods. The absolute...

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

    International Nuclear Information System (INIS)

    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 40oC in a continuous stirring tank reactor. The influence of the initial concentrations of iodine, iodate, hydrogen peroxide, H+ 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 [I2], [IO3-], [H2O2] and [H+]. A rate law has been determined for the two steps for molecular iodine. (author) figs., tabs., 22 refs

  11. 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.

  12. Peroxidation of polyunsaturated fatty acids by lipoxygenases drives ferroptosis.

    Science.gov (United States)

    Yang, Wan Seok; Kim, Katherine J; Gaschler, Michael M; Patel, Milesh; Shchepinov, Mikhail S; Stockwell, Brent R

    2016-08-23

    Ferroptosis is form of regulated nonapoptotic cell death that is involved in diverse disease contexts. Small molecules that inhibit glutathione peroxidase 4 (GPX4), a phospholipid peroxidase, cause lethal accumulation of lipid peroxides and induce ferroptotic cell death. Although ferroptosis has been suggested to involve accumulation of reactive oxygen species (ROS) in lipid environments, the mediators and substrates of ROS generation and the pharmacological mechanism of GPX4 inhibition that generates ROS in lipid environments are unknown. We report here the mechanism of lipid peroxidation during ferroptosis, which involves phosphorylase kinase G2 (PHKG2) regulation of iron availability to lipoxygenase enzymes, which in turn drive ferroptosis through peroxidation of polyunsaturated fatty acids (PUFAs) at the bis-allylic position; indeed, pretreating cells with PUFAs containing the heavy hydrogen isotope deuterium at the site of peroxidation (D-PUFA) prevented PUFA oxidation and blocked ferroptosis. We further found that ferroptosis inducers inhibit GPX4 by covalently targeting the active site selenocysteine, leading to accumulation of PUFA hydroperoxides. In summary, we found that PUFA oxidation by lipoxygenases via a PHKG2-dependent iron pool is necessary for ferroptosis and that the covalent inhibition of the catalytic selenocysteine in Gpx4 prevents elimination of PUFA hydroperoxides; these findings suggest new strategies for controlling ferroptosis in diverse contexts. PMID:27506793

  13. 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. PMID:26538037

  14. Separation of trace amounts of high-valence elements in nickel with extraction and back-extraction using N-benzoyl-N-phenylhydroxylamine

    International Nuclear Information System (INIS)

    The separation and determination of trace amounts of Ti, Zr, Mo, Sn and Hf in Ni were studied. After the sample was dissolved with nitric acid, Ti, Zr, Mo, Sn and Hf were separated from Ni by extracting into benzene with N-benzoyl-N-phenylhydroxylamine (BPA) and subsequently back-extracted into nitric acid for the determination by ICP-AES or ICP-MS. The recoveries of Ti, Zr, Mo, Sn and Hf were satisfactory throughout the extraction with 4.0x10-2 mol·dm-3 BPA in benzene from 1.0 mol·dm-3 nitric acid-0.1 mol·dm-3 trichloroacetic acid solution and the back-extraction with 60% nitric acid. The separation factors (SM = DM/DNi, D = distribution ratios) of Ti, Zr, Mo, Sn and Hf from Ni were 9.9x103 for Ti, 3.2x104 for Zr, 3.2x104 for Mo, 1.3x103 for Sn and 4.0x104 for Hf. The recoveries of Ti, Zr, Mo, Sn and Hf decreased somewhat with increasing the added amount of Ni. The detection limits by ICP-MS were found to be 0.031 μg·g-1 for Ti, 0.046 μg·g-1 for Zr, 0.014 μg·g-1 for Mo, 0.7 μg·g-1 for Sn and 0.006 μg·g-1 for Hf using 0.5 g of Ni sample. The proposed method was applied to analysis of the real sample. (author)

  15. Synthesis and photoluminescence properties of silver(I) complexes based on N-benzoyl-L-glutamic acid and N-donor ligands with different flexibility

    Science.gov (United States)

    Yan, Ming-Jie; Feng, Qi; Song, Hui-Hua

    2016-05-01

    By changing the N-donor ancillary ligand, three novel silver (I) complexes {[Ag(HbzgluO) (4,4‧-bipy)]·H2O}n (1), {[Ag2(HbzgluO)2 (bpe)2]·2H2O}n (2) and {[Ag(HbzgluO)(bpp)]·2H2O}n (3) (H2bzgluO = N-benzoyl-L-glutamic acid, 4,4‧-bipy = 4,4ˊ-bipyridine, bpe = 1,2-di(4-pyridyl)ethane, bpp = 1,3-di(4-pyridyl)propane) were synthesized. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). In this study, the N-donor ligands are changed from rigidity (4,4‧-bipy), quasi-flexibility (bpe) to flexibility (bpp), the structures of complexes also change. Complex 1 features a 1D chain structure which is further linked together to construct a 2D supramolecular structure through hydrogen bonds. Complex 2 is a 1D double-chains configuration which eventually forms a 3D supramolecular network via hydrogen bonding interactions. Whereas, complex 3 exhibits a 2D pleated grid structure which is linked by hydrogen bonding interactions into a 3D supramolecular network. The present observations demonstrate that the modulation of coordination polymers with different structures can accomplish by changing the spacer length of N-donor ligands. In addition, the solid-state circular dichroism (CD) spectra indicated that compound 2 exhibited negative cotton effect which originated from the chiral ligands H2bzgluO and the solid-state fluorescence spectra of the three complexes demonstrated the auxiliary ligands have influence on the photoluminescence properties of the complexes.

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

    International Nuclear Information System (INIS)

    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 (ε = 116 dm3 mol−1 cm−1) supports the presence of Cu(II) centres

  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. Radiosensitization by 2-benzoyl-3-phenyl-6,7-dichloroquinoxaline 1,4-dioxide under oxia and hypoxia in human colon cancer cells

    International Nuclear Information System (INIS)

    The sensitizing effects of 2-benzoyl-3-phenyl-6,7-dichloroquinoxaline 1,4-dioxide (DCQ) and ionizing radiation (IR) were determined in four colon cancer cells and in FHs74Int normal intestinal cells. Cell cycle modulation, TUNEL assay, clonogenic survival and DNA damage were examined under oxia or hypoxia. Effects on apoptotic molecules and on p-Akt and Cox-2 protein expression were investigated. The four cell lines responded differently to DCQ+IR; HT-29 cells were most resistant. Combination treatment caused significant increases in preG1 (apoptosis) in HCT-116, while G2/M arrest occurred in DLD-1. DCQ potentiated IR effects more so under hypoxia than oxia. Pre-exposure of DLD-1 to hypoxia induced 30% apoptosis, and G2/M arrest in oxia. The survival rate was 50% lower in DCQ+IR than DCQ alone and this rate further decreased under hypoxia. FHs74Int normal intestinal cells were more resistant to DCQ+IR than cancer cells.Greater ssDNA damage occurred in DLD-1 exposed to DCQ+IR under hypoxia than oxia. In oxia, p-Akt protein expression increased upon IR exposure and drug pre-treatment inhibited this increase. In contrast, in hypoxia, exposure to IR reduced p-Akt protein and DCQ restored its expression to the untreated control. Apoptosis induced in hypoxic DLD-1 cells was independent of p53-p21 modulation but was associated with an increase in Bax/Bcl-2 ratio and the inhibition of the Cox-2 protein. DCQ is a hypoxic cell radiosensitizer in DLD-1 human colon cancer cells

  19. Biomarkers of lipid peroxidation related to hypertension in aging.

    Science.gov (United States)

    Yavuzer, Hakan; Yavuzer, Serap; Cengiz, Mahir; Erman, Hayriye; Doventas, Alper; Balci, Huriye; Erdincler, Deniz Suna; Uzun, Hafize

    2016-05-01

    The aim of this clinical study was to evaluate the influence of aging on the levels of lipid peroxidation (quantified as thiobarbituric acid-reactive substances (TBARS) content), lipid hydroperoxide (LOOH), hexanoyl lysine (HEL), 8-iso-prostaglandin F2α (8-iso-PGF2α) and total antioxidant capacity (TAC), and determine their relationships to the demographic and cardiovascular risk factors in elderly hypertensive (HT) patients. This study consisted of four groups: two elderly groups with 30 HT patients (11 males, 19 females) and 30 normotensive healthy volunteers (15 males, 15 females), and two young groups with 30 HT patients (13 males, 17 females) and 30 normotensive healthy volunteers (12 males, 18 females). In the elderly control group, the TBARS, LOOH, HEL and 8-iso-PGF2α levels, and the carotid intima media thickness (CIMT) were significantly higher than in the young control group. The TBARS, LOOH, HEL and 8-iso-PGF2α levels and the CIMT measurements were significantly higher in the elderly HT group than in the young HT group. In addition, the TAC levels were significantly lower in the elderly and young HT groups than in the elderly and young control groups. The CIMT was significantly positively correlated with TBARS (r=0.40, P<0.001), HEL (r= 0.30, P=0.001), LOOH (r= 0.44, P<0.001) and 8-iso-PGF2α (r= 0.32, P<0.001) in all of the HT groups. It seems that in elderly patients, the LOOH and TBARS are better biomarkers of lipid peroxidation in hypertension in terms of sensitivity. In all of the HT groups, 8-iso-PGF2α had the highest sensitivity. Hypertension is associated with lipid peroxidation due to an impaired oxidant/antioxidant status. Increased lipid peroxidation and decreased antioxidants with aging indicate that peroxidative damage further increases with higher blood pressure and the aging process. PMID:26763852

  20. 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.

  1. 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.

  2. Photochemical formation of hydrogen peroxide in surface and ground waters exposed to sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, W.J. (Florida International Univ., Miami); Zika, R.G.

    1983-05-13

    A rapid increase in the concentration of hydrogen peroxide was observed when samples of natural surface and ground water from various locations in the United States were exposed to sunlight. The hydrogen peroxide is photochemically generated from organic constitutents present in the water; humic materials are believed to be the primary agent producing the peroxide. Studies with superoxide dismutase suggest that the superoxide anion is the precursor of the peroxide.

  3. Hydrogen peroxide as a soil amendment for greenhouse nasturtium production (Tropaeolum majus L.)

    Science.gov (United States)

    Hydrogen peroxide, H2O2, is a highly reactive oxidizing agent naturally occurring in plants and animals. Plants produce hydrogen peroxide to destroy either infected plant cells or the pathogens within a plant. Hydrogen peroxide also acts as a stress signal to plants. It is approved for the contro...

  4. 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...

  5. A comparative study on two explosive acetone peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Egorshev, V. Yu.; Sinditskii, V.P., E-mail: vps@rctu.ru; Smirnov, S.P.

    2013-12-20

    Highlights: • The most accurate heats of DADP and TATP sublimation were evaluated from experimental vapor pressures in a widened temperature range. • DADP is more volatile while more thermally stable peroxide than TATP. • DADP reveals lesser sensitivity to drop-weight impact, flame temperature, burning rate, and initiating efficiency as compared with TATP. - Abstract: Two explosive cyclic acetone peroxides, diacetone diperoxide (DADP) and triacetone triperoxide (TATP) have been studied in respect of thermal decomposition, burning behavior, impact sensitivity, and initiating efficiency. Using the glass Bourdon gauge technique, the vapor pressures of TATP and DADP were determined over the temperature range 75–144 °C and 67–120 °C, respectively. The kinetic parameters of decomposition of the peroxides in the gas phase have been obtained in the temperature interval of 140–200 °C. The decomposition of both DADP and TATP followed the first-order reaction to high degrees of decay with close activation energies of 159.2 kJ/mol (38.0 kcal/mol) and 165.8 kJ/mol (39.6 kcal/mol), respectively. The decomposition rate constants of DADP were found to be approximately 2 times less than those of TATP. The linear burning rate of DADP measured in a constant-pressure window bomb appeared to be approximately 5 times less than that of TATP. Temperature profiles in the combustion wave were measured at subatmospheric pressures with the help of thin tungsten-rhenium thermocouples. The leading reaction on combustion of both volatile peroxides was assumed to occur in the gas phase. Kinetic parameters of the leading reaction derived from the combustion data showed a good agreement with kinetic parameters of low-temperature thermal decomposition extrapolated to the high-temperature flame zone. In the drop-weight impact test, DADP appeared to be notably less sensitive peroxide than TATP. No deflagration-to-detonation transition was observed when RDX was attempted to explode by

  6. A comparative study on two explosive acetone peroxides

    International Nuclear Information System (INIS)

    Highlights: • The most accurate heats of DADP and TATP sublimation were evaluated from experimental vapor pressures in a widened temperature range. • DADP is more volatile while more thermally stable peroxide than TATP. • DADP reveals lesser sensitivity to drop-weight impact, flame temperature, burning rate, and initiating efficiency as compared with TATP. - Abstract: Two explosive cyclic acetone peroxides, diacetone diperoxide (DADP) and triacetone triperoxide (TATP) have been studied in respect of thermal decomposition, burning behavior, impact sensitivity, and initiating efficiency. Using the glass Bourdon gauge technique, the vapor pressures of TATP and DADP were determined over the temperature range 75–144 °C and 67–120 °C, respectively. The kinetic parameters of decomposition of the peroxides in the gas phase have been obtained in the temperature interval of 140–200 °C. The decomposition of both DADP and TATP followed the first-order reaction to high degrees of decay with close activation energies of 159.2 kJ/mol (38.0 kcal/mol) and 165.8 kJ/mol (39.6 kcal/mol), respectively. The decomposition rate constants of DADP were found to be approximately 2 times less than those of TATP. The linear burning rate of DADP measured in a constant-pressure window bomb appeared to be approximately 5 times less than that of TATP. Temperature profiles in the combustion wave were measured at subatmospheric pressures with the help of thin tungsten-rhenium thermocouples. The leading reaction on combustion of both volatile peroxides was assumed to occur in the gas phase. Kinetic parameters of the leading reaction derived from the combustion data showed a good agreement with kinetic parameters of low-temperature thermal decomposition extrapolated to the high-temperature flame zone. In the drop-weight impact test, DADP appeared to be notably less sensitive peroxide than TATP. No deflagration-to-detonation transition was observed when RDX was attempted to explode by

  7. 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.

  8. In-situ generation of oxygen-releasing metal peroxides

    Science.gov (United States)

    Looney, Brian B.; Denham, Miles E.

    2007-01-09

    A method for remediation of contaminants in soil and groundwater is disclosed. The method generates oxygen releasing solids in groundwater or soil by injecting an aqueous energetic oxidant solution containing free radicals, oxidative conditions can be created within or ahead of a contaminant plume. Some contaminants may be remediated directly by reaction with the free radicals. Additionally and more importantly, the free radicals create an oxidative condition whereby native or injected materials, especially metals, are converted to peroxides. These peroxides provide a long-term oxygen reservoir, releasing oxygen relatively slowly over time. The oxygen can enhance microbial metabolism to remediate contaminants, can react with contaminant metals either to form immobile precipitants or to mobilize other metals to permit remediation through leaching techniques. Various injection strategies for injecting the energetic oxidant solution are also disclosed.

  9. Ultraviolet- and sunlight-induced lipid peroxidation in liposomal membrane

    International Nuclear Information System (INIS)

    Ultraviolet radiation and sunlight caused lipid peroxidation in the liposomal membrane (as detected by measurement of the oxidation index, A233/A215, and the amount of malondialdehyde formed) and made the membrane leaky (as revealed by the release of the trapped chromate anions). The oxidation index and the formation of malondialdehyde increased linearly with increasing dose of radiation and depended significantly on the dose rate. The effects were smaller in liposomes derived from Vibrio cholerae phospholipid than in those derived from egg lecithin. The effects of the radiation dose and dose rate on hemolysis and peroxidation (MDA formation) of the erythrocyte membrane followed a similar pattern. A direct correlation between the percentage leakage of chromate (Y) and the oxidation index (X) of the liposomal system was obtained as Y = 236.5 x X

  10. Laser-based assessment of lipid peroxidation in humans

    Science.gov (United States)

    Giubileo, Gianfranco

    1998-07-01

    Infrared absorption spectroscopy can be performed at very high resolution by tunable diode laser (TDL) based optical systems for any gas with well resolved absorption spectra. In a double beam setup atmospheric trace gas concentration can be measured down to ppb levels. The analysis of trace gases may have useful applications in detecting chemicals in the human breath for non invasive medical diagnostic. The capability of TDL based breath analysis was well demonstrated by monitoring ammonia and methane. In the human body the formation of free radicals does induce oxidative degradation of polyunsaturated fatty acids (lipid peroxidation) which is a damage for cells and organs in the organism. Specific volatile hydrocarbons generated as end product by lipid peroxidation (LP) can be found inside circulating blood and expired breath. TDL based analysis of those specific hydrocarbons (ethane and pentane) in the expired breath can allow a non invasive assessment of the LP extent.

  11. The influence of organic peroxides on platelet aggregation and sensitivity to nitric oxide.

    Science.gov (United States)

    Naseem, K M; Bruckdorfer, K R

    1999-01-01

    The effects of oxidative stress, induced by water-soluble and lipid peroxides, on platelet reactivity and platelet sensitivity to nitric oxide were investigated. Hydrogen peroxide and cumene hydroperoxide potentiated thrombin-induced platelet aggregation. In contrast, 15(S)-hydroperoxyeicosatetraenoic acid had no such effect, while 12(S)-hydroperoxyeicosatetraenoic acid inhibited platelet reactivity. All of the peroxides tested were found to decrease platelet sensitivity to nitric oxide, although the mechanisms by which the various peroxides altered platelet sensitivity to nitric oxide were different. The water-soluble peroxides opposed the actions of nitric oxide without affecting cyclic GMP levels, while 15(S)-hydroperoxyeicosatetraenoic acid caused a significant reduction in the concentration of cyclic GMP formed in response to NO. The data from this study demonstrate that water-soluble and lipid peroxides both affect platelet reactivity and regulation, but by different mechanisms. Thus, caution should be exercised when selecting peroxides to be used as models of oxidative stress. PMID:16801085

  12. 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.

  13. Study of Lipid Peroxidation and Antioxidant Status in Preeclampsia

    OpenAIRE

    Alka Sontakke; Anjum Sayyed

    2013-01-01

    Background: Preeclampsia is a pregnancy spe-cific syndrome, a leading cause of maternal-fetal morbidity and mortality. Free radicals leadto lipid peroxidation which is destructive innature and has been suggested as an aetiologicalfactor in preeclampsia. Aims and Objectives:To determine the role oxidative stress and levelof antioxidants in preeclampsia by estimationof malondialdehyde (MDA) (index of lipidperoxidation) and antioxidants such as uric acid,vitamin C, vitamin E and superoxide dismu...

  14. Cathodic carbon peroxidation process. Surface modifications through oxygen bonding

    OpenAIRE

    Simonet, Jacques

    2013-01-01

    The reduction of oxygen of the air at carbon electrodes in organic aprotic polar solvents in the presence of organic electrophiles such as alkyl iodides may reveal the formation of films of surface-attached alkyl peroxides. Electrochemical charge of carbons (glassy carbon, graphite, industrial coke) in the presence of tetraalkylammonium salt TAAX permits the building of poly-nucleophilic materials that may spontaneously react with air during the work up. This way, a TAA+ hydroperoxydate layer...

  15. Cardiovascular responses to hydrogen peroxide into the nucleus tractus solitarius

    OpenAIRE

    Cardoso, Leonardo Máximo; Colombari, Débora Simões Almeida; Menani, José V; Toney, Glenn M.; Chianca, Deoclécio Alves; Colombari, Eduardo

    2009-01-01

    The nucleus tractus solitarius (NTS), a major hindbrain area involved in cardiovascular regulation, receives primary afferent fibers from peripheral baroreceptors and chemoreceptors. Hydrogen peroxide (H2O2) is a relatively stable and diffusible reactive oxygen species (ROS), which acting centrally, may affect neural mechanisms. In the present study, we investigated effects of H2O2 alone or combined with the glutamatergic antagonist kynurenate into the NTS on mean arterial pressure (MAP) and ...

  16. Fenton peroxidation improves the drying performance of waste activated sludge.

    Science.gov (United States)

    Dewil, Raf; Baeyens, Jan; Neyens, Elisabeth

    2005-01-31

    Advanced sludge treatment processes (AST) reduce the amount of sludge produced and improve the dewaterability, thus probably also affecting the heat transfer properties and the drying characteristics of the sludge. This paper studies the influence of the Fenton peroxidation on the thermal conductivity of the sludge. Results demonstrate that the Fenton's peroxidation positively influences the sludge cake consistency and hence enhances the mechanical dewaterability and the drying characteristics of the dewatered sludge. For the two sludges used in this study, i.e. obtained from the wastewater treatment plants (WWTP) of Tienen and Sint-Niklaas--the dry solids content of the mechanically dewatered sludge increased from 22.5% to 40.3% and from 18.7% to 35.2%, respectively. The effective thermal conductivity k(e) of the untreated and the peroxidized sludges is measured and used to determine the heat transfer coefficient h(s). An average improvement for k(e) of 16.7% (Tienen) and 5.8% (Sint-Niklaas) was observed. Consequently the value of h(s) increased with 15.6% (Tienen) and 5.0% (Sint-Niklaas). This increased heat transfer coefficient in combination with the increased dewaterability has direct implications on the design of sludge dryers. A plate-to-plate calculation of a multiple hearth dryer illustrates that the number of plates required to dry the peroxidized sludge to 90% DS is less than half the number of plates needed to dry untreated sludge. This results in reduced dryer dimensions or a higher capacity for an existing dryer of given dimensions. PMID:15629575

  17. 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.

  18. Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Maděrová, Zdeňka; Šafaříková, Miroslava

    2008-01-01

    Roč. 56, - (2008), s. 7925-7928. ISSN 0021-8561 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate beads * catalase * magnetic separation * Saccharomyces cerevisiae cells * hydrogen peroxide Subject RIV: GM - Food Processing Impact factor: 2.562, year: 2008

  19. The serum lipid peroxide level of civil aircrew members

    International Nuclear Information System (INIS)

    Objective: To observe serum lipid peroxide level and antioxidant capacity in civil aircrew members who occupationally exposed to cosmic radiation at high altitude. Methods: Serum lipid peroxides (MDA), superoxide dismutase (SOD) and total antioxidant activity (TAO) were all determined by chemical colorimetry. The effective doses were estimated in accordance with CARI-6. Results: The three indicators in the aircrew members were all significantly higher than those of ground personnel (P<0.05): their MDA, SOD, TAO levels were (4.09±1.1) nmol/ml, (126.0 ± 17.1)U/ml, (22.01 ± 4.6) U/ml, while those in the ground personnel were (3.79±0.7) nmol/ml, (119.5±10.5) U/ml, (20.02±3.9) U/ml, respectively. The serum MDA levels exhibited a trend of increase with average annual flight hours and average annual effective doses, but were not parallel with total hours service in flying and accumulative effective doses and ages. The MDA showed corresponding dynamic changes with the changes in the flight continuity over a recent period of time. Conclusions: The lipids in the body of aircrew members suffer oxidation damage from cosmic radiation and the antioxidant capacity of the body shows a compensatory increase. The serum lipid peroxide levels are affected obviously by flight burdens and the frequency exposed to cosmic radiation recently. The serum lipid peroxides might be used as a monitoring indicator in cosmic radiation protection for aircrew members

  20. Petroleum Contaminated Soil Treatment Using Surfactant and Hydrogen Peroxide

    OpenAIRE

    Ilza Lobo; Caryna Januario Correr; Carmen Luisa Barbosa Guedes; Otavio Jorge Grigoli Abi-Saab

    2010-01-01

    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 ...

  1. 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.

  2. Aluminum induces lipid peroxidation and aggregation of human blood platelets

    OpenAIRE

    T.J.C. Neiva; D.M. Fries; Monteiro, H. P.; E.A. D'Amico; D.A.F. Chamone

    1997-01-01

    Aluminum (Al3+) intoxication is thought to play a major role in the development of Alzheimer's disease and in certain pathologic manifestations arising from long-term hemodialysis. Although the metal does not present redox capacity, it can stimulate tissue lipid peroxidation in animal models. Furthermore, in vitro studies have revealed that the fluoroaluminate complex induces diacylglycerol formation, 43-kDa protein phosphorylation and aggregation. Based on these observations, we postulated t...

  3. The Effect Paraoxonase-1, Hydrogen Peroxide and Adiponectin

    OpenAIRE

    Baghaiee B; Siahkuhian M; Hakimi M; Bolboli L; Ahmadi Dehrashid K

    2016-01-01

    Background and aims: Paraoxonase-1, Adiponectin and Hydrogen Peroxide are among indexes that are influenced by sedentary lifestyle; and it is possible that they’ll be effective on blood pressure. However, it is not clear the relationship between their changes with blood pressure as a result of participation in regular physical activity. So, the aim of this research was to investigate the effect of 12 weeks moderate aerobic exercise on relationship betw...

  4. Synthesis of Some N-Alkoxycarbonyl-N″-benzoyl-benzamidrazones(p-toluamidrazones) and 1,3,5-Trisubstituted 1,2,4-Triazole Derivatives from N-Benzoylimidates and their Antimicrobial and Anticancer Screening Studies

    Institute of Scientific and Technical Information of China (English)

    BEKIRCAN Olcay; KAHVECI Bahittin; OZGUMUS Osman Birol

    2007-01-01

    Some new N-alkoxycarbonyl-N″-benzoyl-benzamidrazones (p-toluamidrazones) 3a-3d,and 1,3,5-trisubstituted 1,2,4-triazole 4a-4h derivatives by starting from N-benzoylbenzimidates or N-benzoyl-p-toluimidates.The structures of compounds 3 and 4 were established on the basis of elemental analyses,IR,1H NMR,13C NMR and UV data.Antimicrobial experiments of the compounds performed by using agar-well diffusion and broth microdilution methods revealed that only compounds 3a-3d,4a and 4b showed inhibitory effect only on Candida albicans ATCC 60193.However,compound 4b had also specific antibacterial activity against Staphylococcus aureus ATCC 25923.The other compounds showed neither antifungal nor antibacterial activities.Compounds 3a,4a and 4b have been screened on three human tumor cell lines,breast cancer (MCF7),non small cell lung cancer (NCI-H460),and CNS cancer (SF-268) at the National Cancer Institute (NCI),USA,which were found to exhibit low antiproliferative activity.

  5. Determination of alkaline earth metal ions in solar salt by ion chromatography after solvent extraction with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

    International Nuclear Information System (INIS)

    Ion chromatography was effectively applied to the determination of alkaline earth elements (Mg, Ca, Sr and Ba) in solar salt after extraction with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP) into MIBK. The recommended procedure was as follows : the samples (20 ∼ 50 g) were dissolved in about 150 ml of water and the solution was filtered through filter paper into a 200-ml volumetric flask. Ten ml of the sample was pipetted into a centrifuge tube, 5 ml of NH3-NH4Cl buffer solution (pH 9.5), and 15 ml 0.05 M HPMBP-MIBK solution were added. The mixture was shaken vigorously for 30 min. After the phases were separated, an 8-ml portion of the organic phase was transferred into another tube and the alkaline earth elements were back-extracted with 8 ml of the 0.1 M hydrochloric acid. The aqueous phase (6 ml) was heated on a hot plate at 100 deg C in order to remove the dissolved MIBK in the phase. After cooling to room temperature, the solution was diluted to 25 ml with water. A 100 μl aliquot of the sample was analyzed by use of an ion chromatograph (Yokogawa Hokushin Electric Works, model IC 100) equipped with a precolumn (PCX 1, 50 mm x 4.6 mm i.d.) and a separation column (SCX 1, 250 mm x 4.6 mm i.d.) by using 2 mM ethylene diamine-4 mM tartaric acid as a mobile phase (2 ml/min). The detection limits (S/N = 2) were 1.5 ppb for Mg2+, 3.4 ppb for Ca2+, 20 ppb for Sr2+ and 50 ppb for Ba2+, respectively. Relative standard deviation (n = 7) was less than 6.3 % for the simultaneous determination of four elements. The recoveries of Mg2+, Ca2+, Sr2+ and Ba2+ by the proposed method were 100 ∼ 105, 95 ∼ 105, 97 ∼ 101 and 95 ∼ 101 %, respectively. (author)

  6. MOLYBDENUM CATALYZED ACID PEROXIDE BLEACHING OF EUCALYPTUS KRAFT PULP

    Directory of Open Access Journals (Sweden)

    Marcos S. Rabelo

    2008-08-01

    Full Text Available Molybdenum catalyzed peroxide bleaching (PMo Stage consists of pulp treatment with hydrogen peroxide under acidic conditions in the presence of a molybdenum catalyst. Molybdenum is applied in catalytic doses (50-200 mg/kg pulp and may originate from various sources, including (NH46Mo7O24.4H2O, Na2MoO4.2H2O, siliconmolybdate, etc. This work is aimed at optimizing the PMo stage and evaluating its industrial application in the OAZDP sequence. Optimum PMo stage conditions for bleaching eucalyptus pulp were 90 ºC, pH 3.5, 2 h, 0.1 kg/adt Mo and 5 kg/adt H2O2. The PMo stage was more efficient to remove pulp hexenuronic acids than lignin. Its efficiency decreased with increasing pH in the range of 1.5-5.5, while it increased with increasing temperature and peroxide and molybdenum doses. The application of the PMo stage as replacement for the A-stage of the AZDP sequence significantly decreased chlorine dioxide demand. The PMo stage caused a decrease of 20-30% in the generation of organically bound chlorine. The quality parameters of the pulp produced during the PMo stage mill trial were comparable to those obtained with the reference A-stage.

  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. Membrane lipid peroxidation by UV-A: Mechanism and implications

    Energy Technology Data Exchange (ETDEWEB)

    Bose, B.; Agarwal, S.; Chatterjee, S.N. (Saha Institute of Nuclear Physics, Calcutta (India))

    1990-10-01

    UV-A produced a dose-dependent linear increase of lipid peroxidation in liposomal membrane, as detected by the assay of (i) conjugated dienes, (ii) lipid hydroperoxides, (iii) malondialdehydes (MDA), and (iv) the fluorescent adducts formed by the reaction of MDA with glycine and also a linear dose-dependent increase of ({sup 14}C)glucose efflux from the liposomes. UV-A-induced MDA production could not be inhibited by any significant degree by sodium formate, dimethyl sulfoxide, EDTA, or superoxide dismutase but was very significantly inhibited by butylated hydroxytoluene, alpha-tocopherol, sodium azide, L-histidine, dimethylfuran, and beta-carotene. MDA formation increased with an increase in the D{sub 2}O content in water, leading to a maximal amount of nearly 50% enhancement of lipid peroxidation in 100% D{sub 2}O vis-a-vis water used as dispersion medium. The experimental findings indicate the involvement of singlet oxygen as the initiator of the UV-A-induced lipid peroxidation.

  9. Thermodynamic and crystal growth kinetic study of uranium peroxide

    International Nuclear Information System (INIS)

    In the processing of uranium ores, the uranium is recovered from mill leach solutions by precipitation as yellow cake concentrates. Among the different existing processes, the continuous precipitation with hydrogen peroxide in a fluidized bed leads to high-quality solid particles. This paper deals with the determination of the crystal growth mechanism and the kinetic parameters. An experimental study is performed in a stirred batch reactor over a wide range of experimental conditions. The experimental method adapted to the uranium peroxide crystal growth study consists of following hydrogen ion concentration. In order to determine the kinetic parameters, a solubility model has been developed and the calculation of the supersaturation ratio is developed in this article. The deviation from ideality is taken into account and the activity coefficients are calculated by the Specific Interaction Theory. This article gives the results obtained for the uranium peroxide solubility, the supersaturation ratio calculation and crystal growth kinetic law. The treatment of the experimental data shows that the crystal growth rate corresponds to the dislocation mechanism. (authors)

  10. Luminescent probes for detection and imaging of hydrogen peroxide

    International Nuclear Information System (INIS)

    The relevance of hydrogen peroxide (H2O2) in biological processes has been underestimated for a long time. In recent years, various reports showed that H2O2 not only acts as a cytotoxic compound appearing in the course of oxidative stress, but also functions as an important signaling molecule. Fluorescent probes (or indicators) and nanoparticles that respond selectively to hydrogen peroxide can be applied for intracellular measurements or in vivo imaging, and are superior to electrochemical methods, e. g. in terms of spatial resolution. In contrast to previous reviews that concentrated on the adoption of different probes for certain applications, this survey highlights the basic principles of different probes in terms of their chemical design, structures and functionalities. Thus, the probes are classified according to the underlying reaction mechanism: oxidation, hydrolysis, photoinduced electron transfer, and lanthanide complexation. Other assays are based on fluorescent proteins and nanoparticles, and chemi-or bioluminescent reagents. We confine this review to probes that display a more or less distinct selectivity to hydrogen peroxide. Indicators responding to reactive oxygen species (ROS) in general, or to particular other ROS, are not covered. Finally, we briefly discuss future trends and perspectives of these luminescent reporters in biomedical research and imaging. (author)

  11. 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.

  12. 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.

  13. Membrane lipid peroxidation by UV-A: Mechanism and implications

    International Nuclear Information System (INIS)

    UV-A produced a dose-dependent linear increase of lipid peroxidation in liposomal membrane, as detected by the assay of (i) conjugated dienes, (ii) lipid hydroperoxides, (iii) malondialdehydes (MDA), and (iv) the fluorescent adducts formed by the reaction of MDA with glycine and also a linear dose-dependent increase of [14C]glucose efflux from the liposomes. UV-A-induced MDA production could not be inhibited by any significant degree by sodium formate, dimethyl sulfoxide, EDTA, or superoxide dismutase but was very significantly inhibited by butylated hydroxytoluene, alpha-tocopherol, sodium azide, L-histidine, dimethylfuran, and beta-carotene. MDA formation increased with an increase in the D2O content in water, leading to a maximal amount of nearly 50% enhancement of lipid peroxidation in 100% D2O vis-a-vis water used as dispersion medium. The experimental findings indicate the involvement of singlet oxygen as the initiator of the UV-A-induced lipid peroxidation

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

    Science.gov (United States)

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

    2015-10-01

    Organic peroxides, important species in the atmosphere, will promote secondary organic aerosols (SOA) aging, affect HOx radicals cycling, and cause adverse health effects. However, the formation, gas-particle partitioning, and evolution of organic peroxides are extremely complicated and still unclear. In this study, we investigate 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 is an important precursor for SOA at a global scale. We have determined the molar yields of hydrogen peroxide (H2O2), hydroxymethyl hydroperoxide (HMHP), peroxyformic acid (PFA), peroxyacetic acid (PAA) and total peroxides (TPO, including unknown peroxides) and the fraction of peroxides in SOA. Comparing the gas-phase and particle-phase peroxides, we find that gas-particle partitioning coefficients of PFA and PAA are 104 times higher than theoretical prediction, indicating that organic peroxides play a more important role in the SOA formation than expected previously. Here, we give the partitioning coefficients of TPO as (2-3) × 10-4 m3μg-1. Even so, more than 80 % of the peroxides formed in the reaction remain in the gas phase. Water does not affect the total amount of peroxides in either the gas or particle phase, but can change the distribution of gaseous peroxides. About 18 % 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 interpret the unexpected high H2O2 yield under wet conditions. Transformation of organic peroxides to H2O2 also saves OH in the atmosphere, helping to improve the understanding of OH cycling.

  15. Antibacterial activity of hydrogen peroxide and the lactoperoxidase-hydrogen peroxide-thiocyanate system against oral streptococci.

    OpenAIRE

    Thomas, E L; Milligan, T W; Joyner, R E; Jefferson, M M

    1994-01-01

    In secreted fluids, the enzyme lactoperoxidase (LP) catalyzes the oxidation of thiocyanate ion (SCN-) by hydrogen peroxide (H2O2), producing the weak oxidizing agent hypothiocyanite (OSCN-), which has bacteriostatic activity. However, H2O2 has antibacterial activity in the absence of LP and thiocyanate (SCN-). Therefore, LP may increase antibacterial activity by using H2O2 to produce a more effective inhibitor of bacterial metabolism and growth, or LP may protect bacteria against the toxicity...

  16. The Role Of Dicumyl Peroxide (Dcp) In The Strengthening Of Polymer Composites (Peranan Dicumyl Peroxide (Dcp) Terhadap Kekuatan Komposit Polimer)

    OpenAIRE

    Iswanto, Apri Heri; Febrianto, Fauzi

    2009-01-01

    Telah dilakukan sebuah penelitian mengenai sifat fisis dan mekanis komposit dari polipropilen daur ulang dan serbuk kayu dengan menggunakan Maleic Anhydride (MAH) sejumlah 6% (dari berat polipropilen daur ulang) dan Dicumyl Peroxide (DCP) pada berbagai tingkat konsentrasi (5%, 10%, 15%, 20%, 25% dari berat MAH). Dari penelitian tersebut diperoleh hasil bahwa sifat fisis dan mekanis dari komposit tersebut semakin meningkat dengan adanya penambahan konsentrasi DCP. Penambahan konsentrasi DCP se...

  17. Plutonium(IV) peroxide formation in nitric medium and kinetics Pu(VI) reduction by hydrogen peroxide

    International Nuclear Information System (INIS)

    Reduction of plutonium (VI) to Pu(IV) with hydrogen peroxide is a step in industrial processes used to purify plutonium nitrate solutions. This operation must be carefully controlled, in order to avoid any formation of the Pu(IV) peroxide green precipitate and to obtain exclusively Pu(IV). This led us to study the acidity and Pu and H2O2 concentrations influences on the precipitate appearance and to perform a Pu(VI) reduction kinetic study on a wide range of acidities ([HNO3]: 0.5 to 8 M), plutonium concentrations ([Pu(VI)]: 0.1 to 0.8 M) and [H2O2]/[Pu(VI)] ratio (from 1 to 8). Thus, the domain of Pu(IV) peroxide formation and the reactional paths were established. With the exception of 0.5 M nitric acid medium, the kinetic curves show two distinct regims: the first one corresponds to an induction period where the Pu(VI) concentration doesn't change, the second corresponds to a linear decrease of Pu(VI). An increase of the temperature greatly accelerates the Pu(VI) reduction rate while [H2O2]/[Pu(VI)] has almost no influence. The Pu(VI) total reduction time decreases when initial concentration of plutonium increases. By increasing nitric acid concentration from 0.5 M to 6 M, the total Pu(VI) reduction time decreases. This time increases when [HNO3] varies from 6 M to 8 M. (orig.)

  18. Kinetics and mechanism of the furan peroxide formation in the reaction of furfural with hydrogen peroxide in the presence and absence of sodium molybdate

    International Nuclear Information System (INIS)

    Kinetics of the initial stage of the reaction of furfural with hydrogen peroxide are studied in the presence of Na2MoO4 in water and without catalytic additions in n-butanol. Organic peroxide having in its disposal Mo(6), which is the only product on the initial stage of the reaction, is formed since the first minutes of oxidation of furfural by hydrogen peroxide with the presence of Na2MoO4. The mechanisms of conversion of furfural in the Na2MoO4 - H2O system and its oxidation by peroxide without sodium molybdate are discussed. Schemes of formation of furfural complexes based on the results of kinetic studies are suggested. Comparison of obtained data demonstrates that presence of the sodium molybdates in the reaction medium trends to change of reaction procedure in the hydrogen peroxide

  19. [The effect of cadmium chloride and hydrogen peroxide on the lipid peroxidation and fractional composition of lipids in hepatocytes of rats].

    Science.gov (United States)

    Borikov, O Iu; Kaliman, P A

    2004-01-01

    The isolated hepatocytes were incubated in the medium, containing cadmium chloride or hydrogen peroxide. Influence of the latter on the intensity of lipid peroxidation and contents of some lipids fractions, as well as viability of hepatocytes in these conditions has been studied. It is shown that under such cultivation conditions the activation of lipid peroxidation in the hepatocytes takes place. Its activation in presence of cadmium chloride was one of the factors of the membranes damage. The changes in the content of some fractions of lipids were similar both under the incubations of the cells with cadmium chloride and hydrogen peroxide. This allows one to suppose that cadmium chloride causes changes in the lipid composition of membranes as a result of intensification of lipid peroxidation. PMID:15915720

  20. Noninvasive assessment of peroxidative lung damage by HIPDM lung scanning

    Energy Technology Data Exchange (ETDEWEB)

    Miniati, M.; Borrelli, E.; Monti, S.; Cocci, F.; Solfanelli, S.; Giani, L.; Pistolesi, M. (Univ. of Pisa (Italy) Univ. of Siena, (Italy))

    1991-03-15

    The basic compound iodobenzyl-propanediamine (HIPDM), when given intravenously, is extracted by the lungs whence it is effluxed at a slow exponential rate. In humans (normal non smokers), the mean residence time ({bar t}) of 123I-HIPDM, assessed by external detection, averages 7.2 {plus minus} 1.1 hrs. Persistence of HIPDM in lungs is significantly increased in asymptomatic smokers and, to a greater extent, in patients with ARDS. Since production of free oxygen radicals reportedly occurs as a consequence of smoke exposure and in the course of acute lung injury, the authors hypothesized that the prolonged persistence of HIPDM in the lungs of smokers and of patients with ARDS might reflect a peroxidative damage of lung tissue. They tested this hypothesis in rabbits since their baseline HIPDM lung clearance is similar to that of nonsmoking humans. In rabbits, acute lung injury was induced by phorbol myristate acetate. Three hrs after PMA administration, the animals received an i.v. bolus of {sup 131}I-HIPDM. Radioactivity over the chest was recorded for 2 hrs by gamma camera and HIPDM mean residence time in the lungs was computed. Thereafter, the animals were sacrificed and their lungs were removed to measure wet/dry weight ratio as index of lung edema and malondialdehyde (MDA) content as index of lipid peroxidation. HIPDM mean residence time was positively correlated with MDA level in lung tissue, but not with wet/dry weight ratio. Noninvasive assessment of HIPDM lung kinetics may then serve as specific in vivo marker of peroxidative lung injury.

  1. 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.

  2. Apparatus and method for treating pollutants in a gas using hydrogen peroxide and UV light

    Science.gov (United States)

    Cooper, Charles David (Inventor); Clausen, Christian Anthony (Inventor)

    2005-01-01

    An apparatus for treating pollutants in a gas may include a source of hydrogen peroxide, and a treatment injector for creating and injecting dissociated hydrogen peroxide into the flow of gas. The treatment injector may further include an injector housing having an inlet, an outlet, and a hollow interior extending therebetween. The inlet may be connected in fluid communication with the source of hydrogen peroxide so that hydrogen peroxide flows through the hollow interior and toward the outlet. At least one ultraviolet (UV) lamp may be positioned within the hollow interior of the injector housing. The at least one UV lamp may dissociate the hydrogen peroxide flowing through the tube. The dissociated hydrogen peroxide may be injected into the flow of gas from the outlet for treating pollutants, such as nitrogen oxides.

  3. The effect of hydrogen peroxide on polishing removal rate in CMP with various abrasives

    Science.gov (United States)

    Manivannan, R.; Ramanathan, S.

    2009-01-01

    The effect of hydrogen peroxide in chemical mechanical planarization slurries for shallow trench isolation was investigated. The various abrasives used in this study were ceria, silica, alumina, zirconia, titania, silicon carbide, and silicon nitride. Hydrogen peroxide suppresses the polishing of silicon dioxide and silicon nitride surfaces by ceria abrasives. The polishing performances of other abrasives were either unaffected or enhanced slightly with the addition of hydrogen peroxide. The ceria abrasives were treated with hydrogen peroxide, and the polishing of the work surfaces with the treated abrasive shows that the inhibiting action of hydrogen peroxide is reversible. It was found that the effect of hydrogen peroxide as an additive is a strong function of the nature of the abrasive particle.

  4. Hydrogen peroxide distribution, production, and decay in boreal lakes

    OpenAIRE

    Häkkinen, P J; Anesio, Alexandre Magno; Granéli, Wilhelm

    2004-01-01

    The distribution, production, and decay of hydrogen peroxide (H2O2) were studied in 10 boreal lakes of differing physical-chemical characteristics. Diurnal and vertical fluctuations in H2O2 concentration were followed in the lakes by sampling at six depths three times per day. In addition, incubations of water filtered through 0.2-mu mesh were made under artificial irradiation to study the abiotic production and decay of H2O2. H2O2 concentrations after 8 h of artificial irradiation were signi...

  5. Hydrogen Peroxide Produced by Oral Streptococci Induces Macrophage Cell Death

    OpenAIRE

    Okahashi, Nobuo; Nakata, Masanobu; Sumitomo, Tomoko; Terao, Yutaka; Kawabata, Shigetada

    2013-01-01

    Hydrogen peroxide (H2O2) produced by members of the mitis group of oral streptococci plays important roles in microbial communities such as oral biofilms. Although the cytotoxicity of H2O2 has been widely recognized, the effects of H2O2 produced by oral streptococci on host defense systems remain unknown. In the present study, we investigated the effect of H2O2 produced by Streptococcus oralis on human macrophage cell death. Infection by S. oralis was found to stimulate cell death of a THP-1 ...

  6. 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.

  7. Study on hydrogen peroxide generation by water surface discharge

    Czech Academy of Sciences Publication Activity Database

    Yoshihara, K.; Ruma, Ruma.; Aoki, N.; Hosseini, S.H.R.; Sakugawa, T.; Akiyama, H.; Lukeš, Petr

    San Francisco : IEEE, 2013, s. 1-5. ISBN 978-1-4673-5167-6. - (IEEE. 101034). [IEEE Pulsed Power & Plasma Science Conference – PPPS 2013/19./. San Francisco (US), 16.07.2013-21.07.2013] Grant ostatní: Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431203 Institutional support: RVO:61389021 Keywords : underwater discharge * water surface discharge * hydrogen peroxide Subject RIV: BL - Plasma and Gas Discharge Physics http://dx.doi.org/10.1109/PPC.2013.6627582

  8. 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.

  9. Peroxide formation and kinetics of sodium dissolution in alcohols

    International Nuclear Information System (INIS)

    Suitable techniques for sodium removal and decontamination of sodium wetted components of Liquid Metal Fast Reactors (LMFRs) are necessary both for repair, reuse and decommissioning of such components. Among the methods followed for sodium removal, alcohol dissolution is usually employed for small components like bellow sealed valves, gripping tools to handle core components and sodium sampling devices (primary and secondary). One of the concerns in the alcohol dissolution method is the possible role of peroxide formation in the ethoxy group during storage and handling leading to explosion. This paper describes the study of peroxide formation in ethyl carbitol and butyl cellosolve as well as some of the results of dissolution kinetic studies carried out in our laboratory using different alcohols. The peroxide formation of ethyl carbitol and butyl cellosolve were studied by iodometric technique. It has been found that the peroxide formation is less in sodium containing alcohol than in pure one. Ethyl carbitol, butyl cellosolve and Jaysol-SS (mixture of ethyl alcohol, methyl alcohol, isopropyl alcohol and methyl isobutyl ketone) were used in dissolution kinetics studies. The effects due to area and orientation of the fresh sodium surface have also been investigated. The reaction rates were studied in the temperature range of 303-343 K. The rate of dissolution was estimated by measuring the sodium content of alcohol at periodic intervals. It is found that the reaction rate varies in the order of ethyl alcohol-water mixture > Jaysol-SS > butyl cellosolve > ethyl carbitol. While cleaning sodium using alcohol, the concentration of alcohol is held essentially constant throughout the process. The rate of reaction depends only on the amount of sodium and follows pseudo-first order kinetics. Increase in surface area has a marked impact on the dissolution rate at lower temperatures while at higher temperatures, the temperature factor overrides the effect due to surface area

  10. 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.

  11. Modular Advanced Oxidation Process Enabled by Cathodic Hydrogen Peroxide Production

    OpenAIRE

    Barazesh, JM; Hennebel, T; Jasper, JT; Sedlak, DL

    2015-01-01

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low con...

  12. Determination of serum aluminum, platelet aggregation and lipid peroxidation in hemodialyzed patients

    OpenAIRE

    T.J.C. Neiva; A.L. Benedetti; S.M.C.N. Tanaka; Santos, J. I.; E.A. D'Amico

    2002-01-01

    Aluminum (Al3+) overload is frequently associated with lipid peroxidation and neurological disorders. Aluminum accumulation is also reported to be related to renal impairment, anemia and other clinical complications in hemodialysis patients. The aim of the present study was to determine the degree of lipid peroxidation, platelet aggregation and serum aluminum in patients receiving regular hemodialytic treatment. The level of plasma lipid peroxidation was evaluated on the basis of thiobarbitur...

  13. Co-operative inhibitory effects of hydrogen peroxide and iodine against bacterial and yeast species

    OpenAIRE

    Zubko, Elena I; Zubko, Mikhajlo K

    2013-01-01

    Background Hydrogen peroxide and iodine are powerful antimicrobials widely used as antiseptics and disinfectants. Their antimicrobial properties are known to be enhanced by combining them with other compounds. We studied co-operative inhibitory activities (synergism, additive effects and modes of growth inhibition) of hydrogen peroxide and iodine used concurrently against 3 bacterial and 16 yeast species. Results Synergistic or additive inhibitory effects were shown for hydrogen peroxide and ...

  14. Quantifying hydrogen peroxide in iron-containing solutions using leuco crystal violet

    OpenAIRE

    Schoonen Martin A; Pak Aimee; Strongin Daniel; Cohn Corey A

    2005-01-01

    Hydrogen peroxide is present in many natural waters and wastewaters. In the presence of Fe(II), this species decomposes to form hydroxyl radicals, that are extremely reactive. Hence, in the presence of Fe(II), hydrogen peroxide is difficult to detect because of its short lifetime. Here, we show an expanded use of a hydrogen peroxide quantification technique using leuco crystal violet (LCV) for solutions of varying pH and iron concentration. In the presence of the biocatalyst peroxidase, LCV ...

  15. Inhibition of radiation-induced lipid peroxidation by means of gallic polydisulphide

    International Nuclear Information System (INIS)

    Inhibition of radiation-induced lipid peroxidation by means of gallic polydisulphade has been studied. Rats were exposed to X-rays in doses 4,8 and 5,25 Gy. Lipid peroxidation was analysed in blood plasma, membranes of erythrocytes and homogenates of liver and spleen tissues of rats. Polydisulphide of gallic acid was used as inhibitor of lipid peroxidation because of its effective antioxidant properties as have been reported previously. It has been demonstrated that gallic disulphide exhibited high inhibition efficiency in conditions of radiation-induced lipid peroxidation due to the effect of intra-molecular synergism

  16. Effect of radioprotective biogenic amines on peroxide oxidation of lipids in rat small intestine mucosa microsomes

    International Nuclear Information System (INIS)

    The radioprotective biogenic amines, dopamine, histamine, and serotonin inhibited lipid peroxidation in rat small intestine mucosal microsomes. Possible mechanisms of these inhibitory effects are discussed

  17. Ultraviolet radiation-induced lipid peroxidation in liposomal membrane: modification by capsaicin

    International Nuclear Information System (INIS)

    Ultraviolet-radiation has been reported to cause lipid peroxidation in the liposomal membrane. In the present study, treatment with capsaicin, (8-methyl-n-vanillyl-6-nonenamide), the pungent principle of red hot pepper, was shown to modify UV-induced lipid peroxidation in the liposomal membrane. Treatment with low doses of capsaicin (less than 0.1 μg/mL of phosphatidyl choline liposome) produced a significant increase in UV-induced lipid peroxidation, while high doses (0.1-0.5 μg/mL of PC liposome) caused a significant decrease of UV-induced peroxidation

  18. Synergistic extraction of U(VI) and Th(IV) from nitric acid with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (HBMPPT) and tri-n-octylphosphine oxide (TOPO) in toluene

    International Nuclear Information System (INIS)

    The extractant HBMPPT (4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione) was synthesized from HBMPP. Its m.p. was 106-108 deg C. The synergistic extraction of U(VI) and Th(IV) from nitric acid solution by HBMPPT and TOPO in toluene was studied. The extraction ability of HBMPPT was not so high as that of its parent (HBMPP), but when a little tri-n-octylphophine oxide (TOPO) was added the ability to extract U(VI) and Th(IV) was seriously improved. The synergistic extracted complexes may be presented as UO2NO3 x BMPPT x TOPO and UO2(BMPPT)2 x TOPO for U(VI), and Th(NO3)3 x BMPPT x TOPO and Th(NO3)2(BMPPT)2 x TOPO for Th(IV) respectively. (author)

  19. Solvent extraction of lanthanide ions with 1-Phenyl-3-Methyl-4-Benzoyl-Pyrazolone-5 (HPMBP), 2. Extraction of Erbium(III), Ytterbium(III) and Lutetium(III) by HPMBP from aqueous-methanol solutions

    International Nuclear Information System (INIS)

    The solvent extraction of lanthanides(III)(Ln = Er, Yb, Lu) by 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HL) in carbon tetrachloride from aqueous-methanol phase was investigated. The equilibrium constants for the extraction from aqueous-50 % (ν/ν) methanol phase (Kex), two-phase stability constants of the complexes LnL3 (β3*) and stability constants of complexes LnL2+, LnL2+, LnL3(βn)(Ln = Yb, Lu) were calculated. It was confirmed that the addition of methanol to the aqueous phase causes a synergistic effect. The influence of methanol on the dissociation constant of HPMBP (Ka) and the distribution constant of HPMBP (pHL) between carbon tetrachloride and water-methanol solutions was investigated. (Authors)

  20. Solvent extraction of lanthanide ions with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP), III: extraction of gadolinium(III), terbium(III), dysprosium(III), holmium(III), and thulium(III) by HPMBP from aqueous solutions

    International Nuclear Information System (INIS)

    The solvent extraction behaviour of Gd(III), Tb(III), Dy(III), Ho(III), and Tm(III) has been investigated using 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP or HL) in carbon tetrachloride as the extractant. Depending on the concentration of HPMBP in the organic phase the chelates LnL3[Ln(III)=Gd, Tb, Dy, Ho, Tm] and adducts LnL3.HL[Ln(III)=Gd, Tb, Dy, Ho] were extracted. The extraction equilibrium constants (Kex3 or Kex4) for the formation of LnL3 or LnL3.HL and the two-phase stability constants of the chelates or adducts (β3x, β4x) have been evaluated. (authors)

  1. Studies on complexes of Cu(II), Ni(II), Co(II) and Ln(III) with 3-(α-benzoyl) benzylidenehydrazino-5, 6-diphenyl-1,2,4-triazine

    International Nuclear Information System (INIS)

    The synthesis, acid-base equilibria and metal-ion chelating tendencies of 3-(α-benzoyl) benzylidenehydrazino-5,6-diphenyl-1,2,4-triazine (BHT) are reported. From potentiometric equilibrium measurements of hydrogen ion concentration at 30degC and ionic strength 0.10 M KNO3, in 75% (v/v) dioxane-water medium, the values of the stability constants of BHT with transition and lanthanide(III) ions have been evaluated. Probable structures of metal chelates are inferred from electronic absorption spectra and infrared examination of solid complexes. The use of BHT as analytical reagent for the spectrophotometric determination of copper, nickel and cobalt has also been discussed. (author). 4 tabs., 3 figs., 20 refs

  2. (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°.

  3. 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.

  4. Are Sensory TRP Channels Biological Alarms for Lipid Peroxidation?

    Directory of Open Access Journals (Sweden)

    Seung-In Choi

    2014-09-01

    Full Text Available Oxidative stress induces numerous biological problems. Lipid oxidation and peroxidation appear to be important steps by which exposure to oxidative stress leads the body to a disease state. For its protection, the body has evolved to respond to and eliminate peroxidation products through the acquisition of binding proteins, reducing and conjugating enzymes, and excretion systems. During the past decade, researchers have identified a group of ion channel molecules that are activated by oxidized lipids: transient receptor potential (TRP channels expressed in sensory neurons. These ion channels are fundamentally detectors and signal converters for body-damaging environments such as heat and cold temperatures, mechanical attacks, and potentially toxic substances. When messages initiated by TRP activation arrive at the brain, we perceive pain, which results in our preparing defensive responses. Excessive activation of the sensory neuronal TRP channels upon prolonged stimulations sometimes deteriorates the inflammatory state of damaged tissues by promoting neuropeptide release from expresser neurons. These same paradigms may also work for pathologic changes in the internal lipid environment upon exposure to oxidative stress. Here, we provide an overview of the role of TRP channels and oxidized lipid connections during abnormally increased oxidative signaling, and consider the sensory mechanism of TRP detection as an alert system.

  5. Bactericidal activity of metal-mediated peroxide-ascorbate systems.

    Science.gov (United States)

    Drath, D B; Karnovsky, M L

    1974-11-01

    Model systems containing ascorbate, hydrogen peroxide, and divalent copper or cobalt have been shown to possess marked bactericidal activity. At equivalent concentrations, copper-containing systems were more bactericidal than the corresponding mixtures containing cobalt. Cobalt at concentrations below 10(-4) M did not appreciably augment microbicidal activity, whereas systems containing copper at concentrations as low as 5 x 10(-6) M were still capable of causing some bacterial death. Manganese was inactive. None of these systems was as potent as the well known myeloperoxidase-peroxide-halide system. The mechanisms of action of these systems are not as yet clear. The possibility that they function through the generation of superoxide (O(2) (-)), hydroxyl radical (OH.), or other free radicals was explored through the use of superoxide dismutase and several free radical scavengers. It seems likely at present that the two active metal-mediated systems function via separate mechanisms. The copper system acts with dehydroascorbate, whereas the cobalt system does not. Activity in the cobalt system appears to depend upon the generation of free radicals. PMID:16558093

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

    Science.gov (United States)

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

    The Jet Propulsion Laboratory in conjunction with the NASA Planetary Protection Officer has selected vapor phase hydrogen peroxide sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems The goal is to include this technique with appropriate specification in NPG8020 12C as a low temperature complementary technique to the dry heat sterilization process To meet microbial reduction requirements for all Mars in-situ life detection and sample return missions various planetary spacecraft subsystems will have to be exposed to a qualified sterilization process This process could be the elevated temperature dry heat sterilization process 115C for 40 hours which was used to sterilize the Viking lander spacecraft However with utilization of highly sophisticated electronics and sensors in modern spacecraft this process presents significant materials challenges and is thus undesirable to design engineers to achieve bioburden reduction 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 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 Our goal for this study is to determine the minimum VHP process conditions for planetary protection acceptable microbial reduction levels A series of experiments were conducted to

  7. A low-volume microstructured optical fiber hydrogen peroxide sensor

    Science.gov (United States)

    Schartner, E. P.; Murphy, D. F.; Ebendorff-Heidepriem, H.; Monro, T. M.

    2011-05-01

    The ability to measure the concentration of hydrogen peroxide (H2O2) in solution is critical for quality assessment and control in many disparate applications, including wine, aviation fuels and IVF. The objective of this research is to develop a rapid test for the hydrogen peroxide content that can be performed on very low volume samples (i.e. sub-μL) that is relatively independent of other products within the sample. For H2O2 detection we use suspended core optical fibers to achieve a high evanescent field interaction with the fluid of interest, without the constraint of limited interaction length that is generally inherent with nanowire structures. By filling the holes of the fiber with an analyte/fluorophore solution we seek to create a quick and effective sensor that should enable detection of desired species within liquid media. By choosing a fluorophore that reacts with our target species to produce an increase in fluorescence, we can correlate observed fluorescence intensity with the concentration of the target molecule.

  8. Formation of complexes of hydrogen peroxide molecules with DNA

    International Nuclear Information System (INIS)

    A possibility for hydrogen peroxide molecules to form stable complexes with atomic groups in the DNA backbone under the irradiation of the cell medium with high-energy ions has been studied. The energy of complexes is estimated, by taking the electrostatic and van der Waals interactions into account in the framework of the atom-atom potential function method. The interaction with metal counterions, which neutralize the surface charge of a macromolecule under natural conditions, is also taken into consideration. Stable configurations are determined for various complexes consisting of the atoms belonging to a DNA phosphate group, H2O2 and H2O molecules, and a Na+ metal ion. The complexes of hydrogen peroxide molecules with DNA phosphate groups and a counterions are shown to be not less stable than their complexes with water molecules. The attachment of an H2O2 molecule to a phosphate group of the double helix backbone can block the processes of DNA biological functioning and can deactivate the genetic mechanism of a cell

  9. 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.

  10. 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.

  11. 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.

  12. Thermal hazard evaluation of lauroyl peroxide mixed with nitric acid.

    Science.gov (United States)

    Tsai, Lung-Chang; You, Mei-Li; Ding, Mei-Fang; Shu, Chi-Min

    2012-01-01

    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. PMID:22763742

  13. 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.

  14. Isolation of lactic acid bacteria exhibiting high scavenging activity for environmental hydrogen peroxide from fermented foods and its two scavenging enzymes for hydrogen peroxide.

    Science.gov (United States)

    Watanabe, Akio; Kaneko, Chiaki; Hamada, Yasuhiro; Takeda, Kouji; Kimata, Shinya; Matsumoto, Takashi; Abe, Akira; Tanaka, Naoto; Okada, Sanae; Uchino, Masataka; Satoh, Junichi; Nakagawa, Junichi; Niimura, Youichi

    2016-01-01

    To obtain lactic acid bacteria that scavenge environmental hydrogen peroxide, we developed a specialized enrichment medium and successfully isolated Pediococcus pentosaceus Be1 strain from a fermented food. This strain showed vigorous environmental hydrogen peroxide scavenging activity over a wide range of hydrogen peroxide concentrations. High Mn-catalase and NADH peroxidase activities were found in the cell-free extract of the P. pentosaceus Be1 strain, and these two hydrogen peroxide scavenging enzymes were purified from the cell-free extract of the strain. Mn-catalase has been purified from several microorganisms by several researchers, and the NADH peroxidase was first purified from the original strain in this report. After cloning the genes of the Mn-catalase and the NADH peroxidase, the deduced amino acid sequences were compared with those of known related enzymes. PMID:27118075

  15. Solid state and aqueous behavior of uranyl peroxide cage clusters

    Science.gov (United States)

    Pellegrini, Kristi Lynn

    Uranyl peroxide cage clusters include a large family of more than 50 published clusters of a variety of sizes, which can incorporate various ligands including pyrophosphate and oxalate. Previous studies have reported that uranyl clusters can be used as a method to separate uranium from a solid matrix, with potential applications in reprocessing of irradiated nuclear fuel. Because of the potential applications of these novel structures in an advanced nuclear fuel cycle and their likely presence in areas of contamination, it is important to understand their behavior in both solid state and aqueous systems, including complex environments where other ions are present. In this thesis, I examine the aqueous behavior of U24Pp 12, as well as aqueous cluster systems with added mono-, di-, and trivalent cations. The resulting solutions were analyzed using dynamic light scattering and ultra-small angle X-ray scattering to evaluate the species in solution. Precipitates of these systems were analyzed using powder X-ray diffraction, X-ray fluorescence spectrometry, and Raman spectroscopy. The results of these analyses demonstrate the importance of cation size, charge, and concentration of added cations on the aqueous behavior of uranium macroions. Specifically, aggregates of various sizes and shapes form rapidly upon addition of cations, and in some cases these aggregates appear to precipitate into an X-ray amorphous material that still contains U24Pp12 clusters. In addition, I probe aggregation of U24Pp12 and U60, another uranyl peroxide cage cluster, in mixed solvent water-alcohol systems. The aggregation of uranyl clusters in water-alcohol systems is a result of hydrogen bonding with polar organic molecules and the reduction of the dielectric constant of the system. Studies of aggregation of uranyl clusters also allow for comparison between the newer uranyl polyoxometalate family and century-old transition metal polyoxometalates. To complement the solution studies of uranyl

  16. Alkaline peroxide pretreatment of corn stover: effects of biomass, peroxide, and enzyme loading and composition on yields of glucose and xylose

    OpenAIRE

    Hodge David B; Scott-Craig John S; Car Suzana; Banerjee Goutami; Walton Jonathan D

    2011-01-01

    Abstract Background Pretreatment is a critical step in the conversion of lignocellulose to fermentable sugars. Although many pretreatment processes are currently under investigation, none of them are entirely satisfactory in regard to effectiveness, cost, or environmental impact. The use of hydrogen peroxide at pH 11.5 (alkaline hydrogen peroxide (AHP)) was shown by Gould and coworkers to be an effective pretreatment of grass stovers and other plant materials in the context of animal nutritio...

  17. Investigation of Iron Powder, Hydrogen Peroxide and Iron Hydrogen Peroxide for Removal of Acid Yellow Powder 36 Dye from Aqueous Solutions

    OpenAIRE

    Sardar, M.; A Sheikh Mohammadi; A.R Yazdanbakhsh; H Mohammad; M Zarabi

    2010-01-01

    "n "nBackgrounds and Objectives: A great part of organic compounds cause more pollution in natural  waters meet, are chemical dye material. Azo dyes have more usage in different industries. Azo dyes not only give undesirable dye to the water but also have mutation potential and carcinogenesis effects in human and cause the production of toxic substances in water environments.The purpose of this study is investigation of iron powder, hydrogen peroxide and iron powder-hydrogen peroxide pro...

  18. Oxidation resistant peroxide cross-linked UHMWPE produced by blending and surface diffusion

    International Nuclear Information System (INIS)

    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. (author)

  19. 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.

  20. The changes of peroxide number of coconut meal during storage and fermentation processed with Aspergillus nige

    Directory of Open Access Journals (Sweden)

    Helmi Hamid

    1999-06-01

    Full Text Available The effect of fermentation process and duration of storage of fermented coconut meal with Aspergillus niger on its peroxide number has been studied. First stage of experiment was arranged in a completely randomized design with four treatments (raw coconut meal, 0 and 4 day aerobic fermentation incubation and after 2 day anaerobic enzymatic incubation. The peroxide number was determined as potentiality for rancidity. The three incubation processes decreased the peroxide number significantly. The highest reduction was obtained at 4 day aerobic fermentation (49.7%. The decrease of peroxide number of fermented coconut meal was correlated with the decrease of lipid content. The regression coefficient is highly significant (r2 = 0.76, P0.05. Statistical analysis for the peroxide number showed that there was highly significant interaction between the type of substrates and storage temperature. The peroxide number on the fermented products did not significantly increase, where as the non fermented products show significantly increased during storage course. The significant interaction between storage duration and temperature observed. At low temperatures (-13 and 4°C storage the peroxide number increased 44%, while at high temperature (29°C up to 95%. The highest peroxide number on the fermented product (43.5 ppm was obtained at the temperature storage of 29°C for 4 month period. This value is still under rancidity limit (80 ppm. It could be concluded that fermentation process reduced the rancidity of coconut meal.

  1. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Hydrogen Peroxide...

  2. Quantifying hydrogen peroxide in iron-containing solutions using leuco crystal violet

    Directory of Open Access Journals (Sweden)

    Schoonen Martin A

    2005-06-01

    Full Text Available Hydrogen peroxide is present in many natural waters and wastewaters. In the presence of Fe(II, this species decomposes to form hydroxyl radicals, that are extremely reactive. Hence, in the presence of Fe(II, hydrogen peroxide is difficult to detect because of its short lifetime. Here, we show an expanded use of a hydrogen peroxide quantification technique using leuco crystal violet (LCV for solutions of varying pH and iron concentration. In the presence of the biocatalyst peroxidase, LCV is oxidized by hydrogen peroxide, forming a colored crystal violet ion (CV+, which is stable for days. The LCV method uses standard equipment and allows for detection at the low microM concentration level. Results show strong pH dependence with maximum LCV oxidation at pH 4.23. By chelating dissolved Fe(II with EDTA, hydrogen peroxide can be stabilized for analysis. Results are presented for hydrogen peroxide quantification in pyrite–water slurries. Pyrite–water slurries show surface area dependent generation of hydrogen peroxide only in the presence of EDTA, which chelates dissolved Fe(II. Given the stability of CV+, this method is particularly useful for field work that involves the detection of hydrogen peroxide.

  3. Determination of amino acid and protein peroxides by the xylenol orange-Fe(III) complex

    International Nuclear Information System (INIS)

    Oxidative stress imposed on living organisms is believed to lead to the depletion of their antioxidant defences, followed by chemical changes in the cell constituents. These may ultimately develop into pathological conditions such as cancer or cardiovascular disease. An assay of peroxides which could be applied to tissues or simple tissue extracts would prove extremely useful in the studies of the phenomenon of oxidative stress. With this purpose, the authors have tested the ability of two peroxide assay techniques to measure the formation of amino acid and protein peroxides in aqueous solutions irradiated with gamma rays, using a modification of the method based on the oxidation of Fe(II)) by peroxides and complexing of the Fe(III) produced by xylenol orange. The molar extinction coefficients of the peroxides tested were determined by comparison with the well-tested iodometric assay. This work was extended to the detection of all organic peroxides in human blood plasma or serum subjected to oxidative stress, where the iodometric assay proved difficult to apply and unreliable because of the binding of iodine to the blood components. Preliminary results suggest that exposure of serum to gamma radiation leads to immediate peroxidation of the proteins, with a delay before generation of lipid peroxides

  4. Role of spinacea olearcea against radiation lipid peroxidation in mice liver

    International Nuclear Information System (INIS)

    Lipid peroxidation in vivo is a fundamentally deteriorative reaction that is involved in aging process, atheroslerosis and cancer. Lipid peroxidation bring about several changes in biological membrane. Aim of present investigation is to develop promising rich source of antioxidant from the cost-effective point of view

  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

    remove both the parent peroxides and radicals derived from them, whereas methionine and the synthetic phenolic antioxidants Probucol and BHT show little activity. These studies show that cells do not have efficient enzymatic defenses against protein peroxides, with only thiols and ascorbic acid able to...

  6. 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.

  7. Obesity Induces Tissue-Specific Changes in Lipid Peroxidation Defense Enzymes

    Science.gov (United States)

    Lipid peroxidation is thought to be a component of obesity-induced pathology. However, the tissue-dependent changes in lipid peroxidation (LOOH) and LOOH defense mechanisms in response to obesity are unclear. In this work, we utilized 14-week old male, obese Zucker rats and their control, lean litte...

  8. Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

    Science.gov (United States)

    Bedenbaugh, John H.; And Others

    1988-01-01

    Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

  9. The cooperative interaction between vitamin E and vitamin C in suppression of peroxidation of membrane phospholipids

    Energy Technology Data Exchange (ETDEWEB)

    Leung, H.W.; Vang, M.J.; Mavis, R.D.

    1981-01-01

    The time course of peroxidation of rat liver microsomes by FeSO/sub 4/ in the presence of ascorbate showed a delay in the onset of peroxidation compared to the time course when NADPH replaced ascorbate as the electron donor. The delay was consistent with an antioxidant function of ascorbate, possibly mediated through endogenous vitamin E. In order to further investigate the cooperation between ascorbate and vitamin E in suppressing lipid peroxidation, a liposomal system containing polyunsaturated phospholipids was used. Peroxidation was initated by ferrous iron at pH 5, where spontaneous oxidation of Fe/sup 2 +/ did not occur and the antioxidant properties of ascorbic acid could be characterized independently of its pro-oxidant properties as a reducer of Fe/sup 3 +/. Ascorbic acid alone at concentrations of 30-100 ..mu..M delayed peroxidation by 20 min and at higher concentrations prevented peroxidation for 60 min. Physiological levels of vitamin E decreased peroxidation at early time points but the vitamin was apparently consumed during the course of the incubation. The presence of both vitamin C and vitamin E produced suppression of peroxidation at early time points (0-20 min) which was approximately the sum of the individual inhibitions. At longer time points, however, the mixture of antioxidants was much more effective than the sum of both vitamins alone. This suggests that interaction between these antioxidants yields an enhanced delivery of antioxidant protection.

  10. 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

  11. Production of zirconia powders by precipitation stripping with hydrogen peroxide

    International Nuclear Information System (INIS)

    This paper reports on an experimental study to obtain zirconia powders (ZrO2) from carboxylate zirconium solutions followed by hydrogen peroxide stripping and precipitation, that has been carried out. Zirconium carboxylate was prepared by solvent extraction from a chloride aqueous phase using magnesium carboxylate as organic phase. The variables examined in the precipitation were: Temp. 25-90 degrees C, H2O2 concentration: 0.3-5%, pH: 1-9. Organic/Aqueous ration (1/1) and reaction time (30 min.) were maintained at constant levels. The optimum results (98% of precipitation) were achieved at 25 degrees C, 5% H2O2 and pH 5. The precipitates were composed of large amorphous aggregates (2 with large variation of particle size (1-100 μm) was obtained

  12. 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.

  13. LIPID PEROXIDATION AND LIPID PROFILE IN PATIENTS WITH SENILE CATARACT

    Directory of Open Access Journals (Sweden)

    Satya Devi

    2015-11-01

    Full Text Available : Lipid peroxidation products and biochemical parameters like fasting blood sugar and lipid profile were estimated in serum of 40 senile cataract cases (45-60 years and 40 persons of age and sex matched healthy controls. Plasma Thiobarbituric acid reactive substances (TBARS levels [as Malondialdehyde (MDA] were significantly higher in patients with senile cataract (573±64.4nmol/dl, P<0.001 as compared to healthy controls (378±31.31 nmol/dl. Serum cholesterol, Triglycerides, LDLC, VLDLC levels were increased as compared to controls. But HDLC levels were decreased in senile cataract patients as compared to controls. No significant change was observed in FBS values. The present study shows that the oxidative stress may play an important role in the senile cataract.

  14. Hydrogen peroxide and the evolution of oxygenic photosynthesis

    Science.gov (United States)

    Mckay, C. P.; Hartman, H.

    1991-01-01

    Possible pathways for the evolution of oxygenic photosynthesis in the early reducing atmosphere of the earth are discussed. It is suggested that the abiotic production of atmospheric oxidants could have provided a mechanism by which locally oxidizing conditions were sustained within spatially confined habitats thus removing the available reductants and forcing photosynthetic organisms to utilize water (rather than ferrous or sulfide ions) as the electron donor. It is argued that atmospheric H2O2 played the key role in inducing oxygenic photosynthesis, because, as peroxide concentrations local environments increased, primitive organisms would not only be faced with a loss of a reductant, but would be also forced to develop a biochemical apparatus (such as catalase) that would protect them against the products of oxygenic photosynthesis. This scenario allows for the early evolution of oxygenic photosynthesis at the time when global conditions were still anaerobic.

  15. Enzymatic generation of hydrogen peroxide shows promising antifouling effect

    DEFF Research Database (Denmark)

    Kristensen, J.B.; Olsen, Stefan Møller; Laursen, B.S.; Kragh, K.M.; Poulsen, C.H.; Besenbacher, F.; Meyer, R.L.

    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...... Proteobacteria, tested in microtiter plates. However, enzymatically produced H2O2 released from a coating did not impede biofilm formation by bacteria in natural seawater tested in a biofilm reactor. A field trial revealed a noticeable effect of the enzyme system: after immersion in the North Sea for 97 days......, the reference coating without enzymes had 35-40 barnacles, 10% area coverage by diatoms and 15% area coverage by tunicates. The enzyme containing coating had only 6-12 barnacles, 10% area coverage by diatoms and no tunicates. The enzyme system had a performance similar to a copper-based commercial...

  16. Lipid peroxidation and water penetration in lipid bilayers

    DEFF Research Database (Denmark)

    Conte, Elena; Megli, Francesco Maria; Khandelia, Himanshu;

    2012-01-01

    Lipid peroxidation plays a key role in the alteration of cell membrane's properties. Here we used as model systems multilamellar vesicles (MLVs) made of the first two products in the oxidative cascade of linoleoyl lecithin, namely 1-palmitoyl-2-(13-hydroperoxy-9,11-octadecanedienoyl)-lecithin (Hp......(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...

  17. 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.

  18. Inactivation of cellular caspases by peptide-derived tryptophan and tyrosine peroxides

    DEFF Research Database (Denmark)

    Hampton, Mark B; Morgan, Philip E; Davies, Michael Jonathan

    show here that Trp- and Tyr-derived peptide peroxides, generated by singlet oxygen, inhibit caspase activity in the lysates of apoptotic Jurkat cells. N-Ac-Trp-OMe peroxide was the most effective inhibitor, and was 30-fold more effective than H(2)O(2) under identical conditions. As such, protein......Peroxides generated on peptides and proteins within cells, as a result of radical attack or reaction with singlet oxygen, are longer-lived than H(2)O(2) due to their poor removal by protective enzymes. These peroxides readily oxidize cysteine residues and can inactivate thiol-dependent enzymes. We...... peroxides could modulate the progression of apoptosis in cells in which they are generated....

  19. Kinetics of dissolution of uranium metal foil by alkaline hydrogen peroxide

    International Nuclear Information System (INIS)

    To develop a new process for the production of 99Mo using low-enriched uranium targets, uranium dissolution in alkaline hydrogen peroxide was studied. Molybdenum-99 is a parent of the widely used medical isotope 99mTc. The rates of uranium dissolution in alkaline hydrogen peroxide solution were measured in an open, batch-type reactor and were found to be a 0.25th order reaction with respect to equilibrium hydrogen peroxide concentration. In general, uranium dissolution can be classified as a low-base (0.2 M hydroxide) process. In the low-base process, both the equilibrium hydrogen peroxide and the hydroxide concentrations affect the rate of uranium dissolution. In the high-base process, uranium dissolution is independent of alkali concentration; the presence of base affects only the equilibrium concentration of hydrogen peroxide. An empirical kinetics model is proposed and discussed

  20. 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.

  1. Changes of lipid peroxides and alpha-tocopherol in rats with experimentally induced myocardial necrosis.

    Directory of Open Access Journals (Sweden)

    Higuchi,Yoshimi

    1982-04-01

    Full Text Available Myocardial necrosis was produced in rats by injection of isoproterenol (80 mg per kg body weight. Lipid peroxides were measured by the thiobarbituric acid reaction. alpha-Tocopherol was assayed by fluorometric analysis. Immediately after isoproterenol injections, serum lipid peroxides increased and serum alpha-tocopherol decreased, then gradually returned to the pre-injection levels. Lipid peroxides increased more rapidly in the heart and liver than in serum. Alpha-Tocopherol decreased in the heart and liver, then gradually returned to the pre-injection levels. These results indicate that increase in serum lipid peroxides reflects production of peroxides in myocardial tissue and in liver. The decrease in alpha-tocopherol may be due to consumption as anti-oxidants in the vascular system and organs.

  2. Inactivation of possible micromycete food contaminants using the low-temperature plasma and hydrogen peroxide

    Science.gov (United States)

    Čeřovský, M.; Khun, J.; Rusová, K.; Scholtz, V.; Soušková, H.

    2013-09-01

    The inhibition effect of hydrogen peroxide aerosol, low-temperature plasma and their combinations has been studied on several micromycetes spores. The low-temperature plasma was generated in corona discharges in the open air apparatus with hydrogen peroxide aerosol. Micromycete spores were inoculated on the surface of agar plates, exposed solely to the hydrogen peroxide aerosol, corona discharge or their combination. After incubation the diameter of inhibition zone was measured. The solely positive corona discharge exhibits no inactivation effect, the solely negative corona discharge and solely hydrogen peroxide aerosol exhibit the inactivation effect, however their combinations exhibit to be much more effective. Low-temperature plasma and hydrogen peroxide aerosol present a possible alternative method of microbial decontamination of food, food packages or other thermolabile materials.

  3. Inhibition of glyceraldehyde-3-phosphate dehydrogenase by peptide and protein peroxides generated by singlet oxygen attack

    DEFF Research Database (Denmark)

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

    2002-01-01

    Reaction of certain peptides and proteins with singlet oxygen (generated by visible light in the presence of rose bengal dye) yields long-lived peptide and protein peroxides. Incubation of these peroxides with glyceraldehyde-3-phosphate dehydrogenase, in the absence of added metal ions, results in...... stoichiometry of two thiols lost per peroxide consumed. Blocking the thiol residues prevents reaction with the peroxide. This stoichiometry, the lack of metal-ion dependence, and the absence of electron paramagnetic resonance (EPR)-detectable species, is consistent with a molecular (nonradical) reaction between...... inhibited by these peroxides in the absence of added Fe2+-EDTA. The presence of this metal-ion complex enhanced the inhibition observed with these enzymes consistent with the occurrence of radical-mediated reactions. Overall, these studies demonstrate that singlet oxygen-mediated damage to an initial target...

  4. The role of nitric oxide and lipid peroxidation in patients with Plasmodium vivax malaria

    Directory of Open Access Journals (Sweden)

    Polat G.

    2002-12-01

    Full Text Available In this study, we investigated the role of nitric oxide metabolism and lipid peroxidation in patients with P. vivax malaria. The levels of nitrite and nitrate were analyzed using a procedure based on the Griess reaction and malondialdehyde levels which index of lipid peroxidation was determined by thiobarbituric acid reaction. The levels of nitrite/nitrate and malondialdehyde in patients were higher than controls and found to be statistically significant (p < 0.001. We performed this study to determine whether nitric oxide and lipid peroxidation is produced during blood-stage P. vivax malaria. This present study shows that lipid peroxidation occurs in P. vivax malaria. The levels of nitric oxide are associated with lipid peroxidation in this disease.

  5. 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.

  6. Hydrogen Peroxide, Signaling in Disguise during Metal Phytotoxicity

    Science.gov (United States)

    Cuypers, Ann; Hendrix, Sophie; Amaral dos Reis, Rafaela; De Smet, Stefanie; Deckers, Jana; Gielen, Heidi; Jozefczak, Marijke; Loix, Christophe; Vercampt, Hanne; Vangronsveld, Jaco; Keunen, Els

    2016-01-01

    Plants exposed to excess metals are challenged by an increased generation of reactive oxygen species (ROS) such as superoxide (O2•-), hydrogen peroxide (H2O2) and the hydroxyl radical (•OH). The mechanisms underlying this oxidative challenge are often dependent on metal-specific properties and might play a role in stress perception, signaling and acclimation. Although ROS were initially considered as toxic compounds causing damage to various cellular structures, their role as signaling molecules became a topic of intense research over the last decade. Hydrogen peroxide in particular is important in signaling because of its relatively low toxicity, long lifespan and its ability to cross cellular membranes. The delicate balance between its production and scavenging by a plethora of enzymatic and metabolic antioxidants is crucial in the onset of diverse signaling cascades that finally lead to plant acclimation to metal stress. In this review, our current knowledge on the dual role of ROS in metal-exposed plants is presented. Evidence for a relationship between H2O2 and plant metal tolerance is provided. Furthermore, emphasis is put on recent advances in understanding cellular damage and downstream signaling responses as a result of metal-induced H2O2 production. Finally, special attention is paid to the interaction between H2O2 and other signaling components such as transcription factors, mitogen-activated protein kinases, phytohormones and regulating systems (e.g. microRNAs). These responses potentially underlie metal-induced senescence in plants. Elucidating the signaling network activated during metal stress is a pivotal step to make progress in applied technologies like phytoremediation of polluted soils. PMID:27199999

  7. Polysorbates, Peroxides, Protein Aggregation, and Immunogenicity – A growing Concern

    Directory of Open Access Journals (Sweden)

    Edward T. Maggio

    2012-06-01

    Full Text Available Aggregation can have a number of deleterious effects on biotherapeutics including the loss of efficacy, the induction of unwanted immunogenicity, altered pharmacokinetics, and reduced shelf life. Aggregation is ameliorated by the inclusion of surfactants in biotherapeutics formulations, typically non-ionic polymeric ether surfactants. The most commonly used examples are Tween® 20 (Polysorbate 20 and Tween® 80(Polysorbate 80. Others include Triton™ X-100, Pluronic® F-68, Pluronic® F-88, Pluronic®F-127(poloxamers, and Brij 35 (polyoxyethylene alkyl ether. The usefulness of polysorbates, in particular in preventing protein aggregation in biotherapeutic formulations, is well accepted. However, polysorbates contain ether linkages and unsaturated alkyl chains that have been shown to auto-oxidize in aqueous solution to protein-damaging peroxides and reactive aldehydes including formaldehyde and acetaldehyde. The peroxides principally affect methionine and tryptophan moieties. The aldehydes react with primary amino groups on proteins and are known to induce immunogenicity of proteins in the absence of aggregation or adjuvants. Detection of protein aggregation and prevention of aggregation using polysorbates is relatively straightforward using light scattering or size exclusion chromatography methods. Detection of oxidativedamage to amino acyl moieties or increased immunogenicity resulting from the reaction of biotherapeutics with the degradation products of polysorbates is considerably more difficult and has generally been ignored in the scientific literature. As an increasing number of biotherapeutic agents come into use in common clinical practice, including both as innovator and as biosimilar products, these latter issues will come under increased scrutiny. Substitution of non-ionic, non-ether-based surfactants, could offer significant improvements in stability, reduced immunogenicity, and shelf life, and represents a significant unmet need in

  8. 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.

  9. 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.

  10. 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.

  11. Convenient one-pot synthesis of 2,5-anhydro-3,4,6-tri-O-benzoyl-D-(1-/sup 14/C)allononitrile, and its conversion to methyl 2-. beta. -D-ribofuranosyl-4-(2-/sup 14/C)selenazolecarboxylate

    Energy Technology Data Exchange (ETDEWEB)

    Woo, P.W.K.

    1988-10-01

    Reaction of 1-0-acetyl-2,3,5-tri-O-benzoyl-..beta..-D-ribofuranose with (/sup 14/C)cyanotrimethylsilane, generated in situ by reaction of potassium (/sup 14/C)cyanide and chloro-trimethylsilane in the presence of sodium iodide and 2,6-lutidine, gave 2,5-anhydro-3,4,6-tri-O-benzoyl-D-(1-/sup 14/C)allononitrile. Sequential reaction of the latter with hydrogen selenide, ethyl bromopyruvate, and methanolic sodium methoxide gave methyl ..beta..-D-ribofuranosyl-4-(2-/sup 14/C)selenazolcarboxylate, the penultimate precursor to (2-/sup 14/C)CI-935, or 2-..beta..-D-ribofuranosyl-4-(2-/sup 14/C)selenazolecarboxamide.

  12. 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.

  13. Molecular simulations of the effects of phospholipid and cholesterol peroxidation on lipid membrane properties.

    Science.gov (United States)

    Neto, Antenor J P; Cordeiro, Rodrigo M

    2016-09-01

    Non-enzymatic lipid peroxidation may change biomembrane structure and function. Here, we employed molecular dynamics simulations to study the effects of either phospholipid or cholesterol peroxidation individually, as well as the combined peroxidation of both components. When lipids were peroxidized, the generated OOH groups migrated to the membrane surface and engaged in H-bonds with each other and the phospholipid carbonyl ester groups. It caused the sn-2 acyl chains of phospholipid hydroperoxides to bend and the whole sterol backbone of cholesterol hydroperoxides to tilt. When phospholipids were kept intact, peroxidation of the sterol backbone led to a partial degradation of its condensing and ordering properties, independently of the position and isomerism of the OOH substitution. However, even in massively peroxidized membranes in which all phospholipids and cholesterol were peroxidized, the condensing and ordering properties of the sterol backbone were still significant. The possible implications for the formation of membrane lateral domains were discussed. Cholesterol peroxyl radicals were also investigated and we found that the OO groups did not migrate to the headgroups region. PMID:27349733

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Testing of a Peroxidation Systems, Inc. perox-pure SSB-30

    International Nuclear Information System (INIS)

    A facility is being designed and built at the US Department of Energy (DOE) Hanford Site to treat water containing a variety of organic and inorganic compounds. An ultraviolet light/hydrogen peroxide system, manufactured by Peroxidation Systems, Inc. (PSI), has been chosen to destroy the organic compounds in the feed stream. The PSI perox-pure trademark model SSB-30 has been tested by the Westinghouse Hanford Company (WHC) to provide data for permit documentation and to determine appropriate operating conditions. The destruction of the organic compounds was demonstrated with several feed compositions at different ultraviolet light exposures and hydrogen peroxide concentrations

  1. Determination of hydrogen peroxide concentration in THOR coolant during reactor operation

    International Nuclear Information System (INIS)

    The concentrations of hydrogen peroxide formed in the coolant due to radiolysis were studied during THOR operation at 1 MW. The relation between doses and hydrogen peroxide formation in a neutron-gamma mixed field was investigated. The initial concentration was 2.3x10-5 g/ml at the beginning of reactor operation, and then it increased rather rapidly at the first 9 hs. The increasing rate slowed down till the end of 30 hs of operation. The maximum concentration of hydrogen peroxide was found to be 4.7x10-5 g/ml, and its decrease followed the exponential curve. (author)

  2. Effects of peroxides on susceptibilities of Escherichia coli and Mycobacterium smegmatis to isoniazid.

    OpenAIRE

    Rosner, J. L.; Storz, G

    1994-01-01

    Escherichia coli strains were previously found to be susceptible to the antituberculosis drug isonicotinic acid hydrazide (isoniazid [INH]) when they carried certain mutations that also sensitize them to peroxides: a deletion in oxyR, a redox-sensitive regulator of hydrogen peroxide-inducible genes, or mutations in both katG and ahpCF, OxyR-regulated genes encoding hydroperoxidase I, and an alkyl hydroperoxide reductase. To test whether INH, like peroxides, activates OxyR, the effect of INH o...

  3. Rheological behaviour of polyethylene with peroxide crosslinking agent. Ismaeil Ghasemi, Peter Szabo and Henrik Koblitz Rasmussen

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Ghasemi, Ismaeil; Szabo, Peter

    One of the most important post-reactor modifications of polyethylene is cross-linking. Cross-linking improves some properties of polyethylene such as: environmental stress cracking resistance (ECSR), chemical and abrasion resistance, service temperature etc. In this study the rheological variation...... due to a peroxide cross-linking reaction of low-density polyethylene (LDPE) was tracked by a combination of creep tests and differential scanning calorimetry (DSC) tests in isothermal conditions. The peroxide was di-cumyl peroxide and its concentration was 2 wt%. The experiments were carried out at...

  4. Tryptophan fluorescence of erythrocyte ghosts after irradiation and unitiation of lipid peroxidation by Fe2+

    International Nuclear Information System (INIS)

    It was shown that under the effect of Fe2+ - initiated lipid peroxidation and ionizing radiation tryptophan fluorescence parameters (i.e. intensity and polarization) were subjected to similar changes. Shortly (15 min) after irradiation no changes were observed in the level of products reacting with thiobarbituric acid. It is concluded that the process and products of lipid peroxidation do not markedly contribute to the postirradiation alteration of tryptophan fluorescence. At the same time additional postirradiation damages to proteins can be attributed to activation of lipid peroxidation

  5. Lipid peroxidation causes endosomal antigen release for cross-presentation.

    Science.gov (United States)

    Dingjan, Ilse; Verboogen, Daniëlle Rj; Paardekooper, Laurent M; Revelo, Natalia H; Sittig, Simone P; Visser, Linda J; Mollard, Gabriele Fischer von; Henriet, Stefanie Sv; Figdor, Carl G; Ter Beest, Martin; van den Bogaart, Geert

    2016-01-01

    Dendritic cells (DCs) present foreign antigen in major histocompatibility complex (MHC) class I molecules to cytotoxic T cells in a process called cross-presentation. An important step in this process is the release of antigen from the lumen of endosomes into the cytosol, but the mechanism of this step is still unclear. In this study, we show that reactive oxygen species (ROS) produced by the NADPH-oxidase complex NOX2 cause lipid peroxidation, a membrane disrupting chain-reaction, which in turn results in antigen leakage from endosomes. Antigen leakage and cross-presentation were inhibited by blocking ROS production or scavenging radicals and induced when using a ROS-generating photosensitizer. Endosomal antigen release was impaired in DCs from chronic granulomatous disease (CGD) patients with dysfunctional NOX2. Thus, NOX2 induces antigen release from endosomes for cross-presentation by direct oxidation of endosomal lipids. This constitutes a new cellular function for ROS in regulating immune responses against pathogens and cancer. PMID:26907999

  6. Hydrogen peroxide produced by oral Streptococci induces macrophage cell death.

    Directory of Open Access Journals (Sweden)

    Nobuo Okahashi

    Full Text Available Hydrogen peroxide (H2O2 produced by members of the mitis group of oral streptococci plays important roles in microbial communities such as oral biofilms. Although the cytotoxicity of H2O2 has been widely recognized, the effects of H2O2 produced by oral streptococci on host defense systems remain unknown. In the present study, we investigated the effect of H2O2 produced by Streptococcus oralis on human macrophage cell death. Infection by S. oralis was found to stimulate cell death of a THP-1 human macrophage cell line at multiplicities of infection greater than 100. Catalase, an enzyme that catalyzes the decomposition of H2O2, inhibited the cytotoxic effect of S. oralis. S. oralis deletion mutants lacking the spxB gene, which encodes pyruvate oxidase, and are therefore deficient in H2O2 production, showed reduced cytotoxicity toward THP-1 macrophages. Furthermore, H2O2 alone was capable of inducing cell death. The cytotoxic effect seemed to be independent of inflammatory responses, because H2O2 was not a potent stimulator of tumor necrosis factor-α production in macrophages. These results indicate that streptococcal H2O2 plays a role as a cytotoxin, and is implicated in the cell death of infected human macrophages.

  7. Antioxidative effects of whey protein on peroxide-induced cytotoxicity.

    Science.gov (United States)

    Xu, R; Liu, N; Xu, X; Kong, B

    2011-08-01

    Myoblastic toxicity is a major adverse effect caused by reactive oxygen species (ROS) when exercising heavily. Although protection or alleviation of ROS toxicity can be achieved by administration of antioxidant vitamins such as vitamin E and vitamin C, their protective effect remains controversial. Thus, alternative natural antioxidants may be potential candidates for foods for athletes. In this research, we investigated the antioxidative effect of whey protein against hydrogen peroxide (H(2)O(2)) toxicity using C(2)C(12) myoblasts. Whey protein pre-incubation prevented the decrease in cell viability after H(2)O(2) treatment. The production of 8-hydroxydeoxyguanosine associated with DNA oxidative damage was also inhibited by the whey protein pre-incubation. Endogenous antioxidant defense, such as glutathione, catalase, and superoxide dismutase activity, was also modulated by the antioxidant. At the same time, enhanced mRNA expression levels of heme oxygenase-1 and NADPH quinone oxidoreductase-1 were observed in cells pre-incubated with whey protein before H(2)O(2) abuse. These findings suggest that whey protein improved the antioxidant capacity against acute oxidative stress through multiple pathways and this protein may serve as an alternative source of antioxidants for prevention of athletic injuries caused by ROS. PMID:21787910

  8. Optimization of Hydrogen Peroxide Detection for a Methyl Mercaptan Biosensor

    Directory of Open Access Journals (Sweden)

    Shi-Gang Sun

    2013-04-01

    Full Text Available Several kinds of modified carbon screen printed electrodes (CSPEs for amperometric detection of hydrogen peroxide (H2O2 are presented in order to propose a methyl mercaptan (MM biosensor. Unmodified, carbon nanotubes (CNTs, cobalt phthalocyanine (CoPC, Prussian blue (PB, and Os-wired HRP modified CSPE sensors were fabricated and tested to detect H2O2, applying a potential of +0.6 V, +0.6 V, +0.4 V, −0.2 V and −0.1 V (versus Ag/AgCl, respectively. The limits of detection of these electrodes for H2O2 were 3.1 μM, 1.3 μM, 71 nM, 1.3 μM, 13.7 nM, respectively. The results demonstrated that the Os-wired HRP modified CSPEs gives the lowest limit of detection (LOD for H2O2 at a working potential as low as −0.1 V. Os-wired HRP is the optimum choice for establishment of a MM biosensor and gives a detection limit of 0.5 μM.

  9. Space hardware compatibility tests with hydrogen peroxide gas plasma sterilization

    Science.gov (United States)

    Faye, Delphine; Aguila, Alexandre; Debus, Andre; Remaury, Stephanie; Nabarra, Pascale; Darbord, Jacques C.; Soufflet, Caroline; Destrez, Philippe; Coll, Patrice; Coscia, David

    The exploration of the Solar System shall comply with planetary protection requirements handled presently by the Committee of Space Research (COSPAR). The goal of planetary protection is to protect celestial bodies from terrestrial contamination and also to protect the Earth environment from an eventual contamination carried by return samples or by space systems. For project teams, avoiding the biological contamination of other Solar System bodies such as Mars imposes to perform unusual tasks at technical and operational constraints point of view. The main are the reduction of bioburden on space hardware, the sterile integration of landers, the control of the biological cleanliness and the limitation of crash probability. In order to reduce the bioburden on spacecraft, the use of qualified sterilization processes may be envisaged. Since 1992 now, with the Mars96 mission, one of the most often used is the Sterrad(R) process working with hydrogen peroxide gas plasma. In the view of future Mars exploration programs, after tests performed in the frame of previous missions, a new test campaign has been performed on thermal coatings and miscellaneous materials coming from an experiment in order to assess the compatibility of space hardware and material with this sterilization process.

  10. 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.

  11. Lipid Peroxidation in Rat Liver using Different Vegetable Oils

    International Nuclear Information System (INIS)

    The objective of the study was to evaluate the effect of different vegetable oils (Red Palm Olien (RPO), Palm Olein (PO), Corn Oil (CO) and Coconut Oil on lipid peroxidation of rat liver. One hundred and thirty two Sprague Dawley male rats were randomly divided into two groups. The first group contains seventy two rats were divided into twelve groups of 6 rats per group and were treated with different concentrations of RPO (5 %, 10 % and 15 %) for 2, 4 and 8 weeks. The second group contains sixty male rats were randomly divided into ten groups of 6 rats per group and were treated with 15 % of RPO, PO, CO and COC for 4 and 8 weeks. The results shows that after 8 weeks of treatment the malonaldehyde (MDA) value in RPO group was significantly lower (P≤0.05) than control or vegetable oils studied. These experiments suggested that red palm olein antioxidants present in rat diets may better attenuate peroxyl radical than other vegetable oil studied. (author)

  12. Etching of germanium-tin using ammonia peroxide mixture

    International Nuclear Information System (INIS)

    The wet etching of germanium-tin (Ge1-xSnx) 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 Ge1-xSnx 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 Ge1-xSnx 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 Ge0.918Sn0.082 samples. Both root-mean-square roughness and undulation periods of the Ge1-xSnx surface were observed to increase with increasing t. This work provides further understanding of the wet etching of Ge1-xSnx using APM and may be used for the fabrication of Ge1-xSnx-based electronic and photonic devices

  13. 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.

  14. Electronic tongue for nitro and peroxide explosive sensing.

    Science.gov (United States)

    González-Calabuig, Andreu; Cetó, Xavier; Del Valle, Manel

    2016-06-01

    This work reports the application of a voltammetric electronic tongue (ET) towards the simultaneous determination of both nitro-containing and peroxide-based explosive compounds, two families that represent the vast majority of compounds employed either in commercial mixtures or in improvised explosive devices. The multielectrode array was formed by graphite, gold and platinum electrodes, which exhibited marked mix-responses towards the compounds examined; namely, 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), pentaerythritol tetranitrate (PETN), 2,4,6-trinitrotoluene (TNT), N-methyl-N,2,4,6-tetranitroaniline (Tetryl) and triacetone triperoxide (TATP). Departure information was the set of voltammograms, which were first analyzed by means of principal component analysis (PCA) allowing the discrimination of the different individual compounds, while artificial neural networks (ANNs) were used for the resolution and individual quantification of some of their mixtures (total normalized root mean square error for the external test set of 0.108 and correlation of the obtained vs. expected concentrations comparison graphs r>0.929). PMID:27130125

  15. Lipid Peroxidation and Electrolytes in Irradiated Rats Treated with Caffeine

    International Nuclear Information System (INIS)

    This Study was conducted to elarify the potential role of caffeine (1,3,7-trimethyl xanthine), a major component of coffee, against damages induced by gamma rays. Thirty adult female albino rats (130+10) were divided into three groups, each of ten animals. The first group acted as control animals. The second was sujected to a single dose of (7) Gy whole body gamma irradiation. The third group was injected intraperitoneally with a single dose (80mg/kg body weight) of caffeine one-hour prior irradiation. Blood samples were collected five time intervals 1,3,7,15 and 30 days post-irradiation. The content of serum lipid peroxides was measured as thiobarbituric acid reactive substance (TBARS). Electrolytes as calcium (Ca2+), sodium (Na+) and potassium (K+) and levels were estimated and Na+/K+ ratio was calculated. Also serum enzymes as alkaline phosphatase (ALP) and aminotransaminases (AST and ALT) activity levels were measured. The data revealed significant increase in TBARS, AST and ALT levels in serum due to irradiation exposure. While, radiation induced significant decrease in serum level of ALP, level of electrolytes Ca2+, Ma+, and Na+/K+ ratio. On the other hand, group injected intraperitoneally with caffeine pre-irradiation exhibited reduction in the changes produced by gamma-radiation with variable degree. The data showed that this antioxidant confers protection damage inflicted by radiation when given prior to irradiation exposure on the examined parameters

  16. 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. PMID:26603095

  17. 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.

  18. 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.

  19. DNA-repair capacity and lipid peroxidation in chronic alcoholics.

    Science.gov (United States)

    Topinka, J; Binková, B; Srám, R J; Fojtíková, I

    1991-07-01

    The possible impact of long-term overexposure to ethanol was studied in a group of chronic alcoholics in the psychiatric hospital. The level of DNA methylation and unscheduled DNA synthesis (UDS) induced by N-methyl-N-nitrosourea (MNU) in lymphocytes and lipid peroxidation (LPO) in plasma were used as markers of injury caused by alcohol abuse. The data were correlated with plasma levels of some natural antioxidants (vitamins A, C and E) and vitamin B12. The following results were obtained. The degree of DNA methylation by MNU in lymphocytes was the same in the exposed and control groups under our experimental conditions. The DNA excision-repair capacity of lymphocytes measured as UDS was decreased in alcoholics (p less than 0.01) and LPO in plasma was significantly higher (p less than 0.01) as a consequence of alcohol overconsumption. By the simple regression method, a correlation was found between LPO and vitamin C levels (LPO = -0.078 x vit. C + 1.9; p less than 0.05) and between UDS and LPO values (UDS = -0.384 x LPO + 4.1; p less than 0.05). These results support the hypothesis of a connection of cell membrane status and DNA damage and repair and the possible role of active oxygen species in cell damage caused by ethanol. PMID:2067553

  20. Preliminary flight test of hydrogen peroxide retro-propulsion module

    Science.gov (United States)

    An, Sungyong; Jo, Sungkwon; Wee, Jeonghyun; Yoon, Hosung; Kwon, Sejin

    2010-09-01

    In this paper, we present the development of a retro-thruster, the design of a retro-propulsion module, and a preliminary flight of the module in a landing demonstration. First, a retro-monopropellant thruster with the maximum thrust of 350 N that employs hydrogen peroxide as a monopropellant was developed. It's thrust force, efficiency of characteristic velocity, and specific impulse were evaluated during the course of it's development. To control the thrust force, two solenoid valves and a pulse width modulation (PWM) flow control valve were incorporated into the thruster design. Second, a retro-propulsion module with a wet mass of 23 kg was designed and fabricated. All the required components including tanks, propellant tubes, a pressure regulator, valves, a retro-thruster, and support structure were integrated into the module. Finally, a preliminary flight test with thrust and altitude control was carried out successfully. In this test, the throttling of the thrust force and altitude control was performed manually for safety purposes.

  1. 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.

  2. 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.

  3. UV-C photolysis of endocrine disruptors. The influence of inorganic peroxides

    International Nuclear Information System (INIS)

    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 10-3 mol Einstein-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 109 M-1 s-1), doxycycline (k > 1.5 x 109 M-1 s-1) and mefenamic acid (k > 11.0 x 109 M-1 s-1).

  4. Amelioration of ionizing radiation induced lipid peroxidation in mouse liver by Moringa oleifera Lam. leaf extract

    International Nuclear Information System (INIS)

    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. (author)

  5. The influence of 2-amino-2-thiazoline on lipid peroxidation in saccharomyces cerevisiae and Pichia guilliermondii

    International Nuclear Information System (INIS)

    The influence of 2-amino-2-thiazoline on lipid peroxidation in yeasts Saccharomyces cerevisiae and Pichia guilliermondi has been studied in vivo and in vitro. In the case the radioresistance of diploid yeasts-saccharomycetes is changed the radiprotector can produce a direct effect on lipid peroxidation. Different efficiency of the preparation with regard to different strains of one and the same yeast culture is explained by its different influence on the content of endogenous radiprotective factors exerting a control over the accretion of lipid peroxidation products. The observed differences in the lag-periods of peroxidation in Sacharomyces cerevisiae and Pichia guilliermondii correspond to the level of their natural antioxidant activity of lipids

  6. 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.

  7. [The Clinical Application Status and Development Trends of Hydrogen Peroxide Low Temperature Plasma Sterilizers].

    Science.gov (United States)

    Zhuang, Min; Zheng, Yunxin; Chen, Ying; Hou, Bin; Xu, Zitian

    2016-01-01

    The hydrogen peroxide low temperature plasma sterilization technology solved the problems of thermo-sensitive materials' disinfection and sterilization based on its development and unique characteristics. This paper introduced the researches of clinical application quality control, and showed the hydrogen peroxide low temperature plasma sterilizers were being widely used in hospitals and highly recognized. According to the clinical data and the literatures of the domestic equipment in preliminary application, it could be concluded that the technology maturity of domestic hydrogen peroxide low temperature plasma sterilizers was in a high level. The advantages of using domestic hydrogen peroxide low temperature plasma sterilizers to do disinfection and sterilization included lower cost, safer, faster and non-toxic, etc. Also the management system should be improved and the clinical staff should master the technical essentials, obey the procedures strictly, verify periodically and offer full monitoring to upgrade the quality of sterilization. PMID:27197500

  8. 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}).

  9. 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.

  10. Turmeric and black pepper spices decrease lipid peroxidation in meat patties during cooking

    OpenAIRE

    Zhang, Yanjun; Henning, Susanne M.; Lee, Ru-po; Huang, Jianjun; Zerlin, Alona; Li, Zhaoping; Heber, David

    2015-01-01

    Abstract Spices are rich in natural antioxidants and have been shown to be potent inhibitors of lipid peroxidation during cooking of meat. Turmeric contains unique conjugated curcuminoids with strong antioxidant activity. Piperine, one of the main constituents of black pepper, is known to increase the bioavailability of curcuminoids in mouse and human studies when consumed with turmeric. We investigated whether adding black pepper to turmeric powder may further inhibit lipid peroxidation when...

  11. Functional, structural, and chemical changes in myosin associated with hydrogen peroxide treatment of skeletal muscle fibers

    OpenAIRE

    Prochniewicz, Ewa; Lowe, Dawn A.; Spakowicz, Daniel J; Higgins, LeeAnn; O'Conor, Kate; Thompson, LaDora V.; Deborah A Ferrington; Thomas, David D.

    2007-01-01

    To understand the molecular mechanism of oxidation-induced inhibition of muscle contractility, we have studied the effects of hydrogen peroxide on permeabilized rabbit psoas muscle fibers, focusing on changes in myosin purified from these fibers. Oxidation by 5 mM peroxide decreased fiber contractility (isometric force and shortening velocity) without significant changes in the enzymatic activity of myofibrils and isolated myosin. The inhibitory effects were reversed by treating fibers with d...

  12. Mitochondria are the source of hydrogen peroxide for dynamic brain-cell signaling

    OpenAIRE

    Bao, Li; Avshalumov, Marat V.; Patel, Jyoti C.; Lee, Christian R.; Miller, Evan W.; Chang, Christopher J.; Rice, Margaret E.

    2009-01-01

    Hydrogen peroxide (H2O2) is emerging as a ubiquitous small-molecule messenger in biology, particularly in the brain, but underlying mechanisms of peroxide signaling remain an open frontier for study. For example, dynamic dopamine transmission in dorsolateral striatum is regulated on a subsecond timescale by glutamate via H2O2 signaling, which activates ATP-sensitive potassium (KATP) channels to inhibit dopamine release. However, the origin of this modulatory H2O2 has been elusive. Here we add...

  13. Effect of ethanol and the catalase inhibitor aminotriazole on lipid peroxidation in the rat myocardium

    International Nuclear Information System (INIS)

    The authors study the effect of chronic administration of ethanol and aminotriazole on the level of lipid peroxidation in the ray myocardium. The action of natural and artificial antioxidants on alcohol-induced lipid peroxidation also was studied. To determine the level of chemiluminescence, 1 ml of a sample of nuclear free homogenate or of the total fraction of particles was introduced for radioactivity measurement. After incubation the spontaneous weak luminescence was measured

  14. Reaction kinetics of hydrogen peroxide in teeth for teeth whitening applications

    OpenAIRE

    Fang, Grace C.

    2013-01-01

    Clinical parameters for dental whitening such as peroxide concentration and treatment time have been empirically derived. However, limited quantitative analyses examine reactivity of hydrogen peroxide on in vivo tooth stains under various catalytic settings. The wide range of possible activators and stains are challenging in creating a standardized tooth model to isolate various effects for clinical applications. This study uses three model systems to determine the effects of heat, light, met...

  15. Macrophage Response to UHMWPE Submitted to Accelerated Ageing in Hydrogen Peroxide

    OpenAIRE

    Rocha, Magda F.G.; Mansur, Alexandra A.P.; Martins, Camila P.S.; Edel F Barbosa-Stancioli; Mansur, Herman S

    2010-01-01

    Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important properties to extend the longevity of knee prostheses. The present study investigated the accelerated ageing of UHMWPE in hydrogen peroxide highly oxidative chemical environment. The sliced samples of UHMWPE were oxidized in a hydrogen peroxide solution for 120 days with their total level o...

  16. Measurements of the partitioning of hydrogen peroxide in a stratiform cloud

    OpenAIRE

    Noone, Kevin J.; OGREN, JOHN A.; NOONE, K. BIRGITTA; HALLBERG, ANNELI; Fuzzi, Sandro; Lind, John A.

    2011-01-01

    Simultaneous measurements of hydrogen peroxide in cloud droplets and in the air in which the droplets were suspended are presented. In addition, a description of the new technique used to make the measurements is also presented. The ratio of the measured cloudwater concentration to the equilibrium cloudwater concentration predicted using Henry's law and the measured gas-phase hydrogen peroxide was 0.64 (S.D = 0.32, n= 74). Analysis of both random and potential systematic errors indicate that ...

  17. Oxidative Stress and Lipid Peroxidation Products in Cancer Progression and Therapy

    OpenAIRE

    Giuseppina Barrera

    2012-01-01

    The generation of reactive oxygen species (ROS) and an altered redox status are common biochemical aspects in cancer cells. ROS can react with the polyunsaturated fatty acids of lipid membranes and induce lipid peroxidation. The end products of lipid peroxidation, 4-hydroxynonenal (HNE), have been considered to be a second messenger of oxidative stress. Beyond ROS involvement in carcinogenesis, increased ROS level can inhibit tumor cell growth. Indeed, in tumors in advanced stages, a further ...

  18. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype

    OpenAIRE

    Ruslana Vasylkovska; Natalia Petriv; Halyna Semchyshyn

    2015-01-01

    Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i) hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii) the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii) meta...

  19. INVOLVEMENT OF CATALASE IN SACCHAROMYCES CEREVISIAE HORMETIC RESPONSE TO HYDROGEN PEROXIDE

    Directory of Open Access Journals (Sweden)

    Ruslana Vasylkovska

    2015-05-01

    Full Text Available In this study, we investigated the relationship between catalase activity and H2O2-induced hormetic response in budding yeast S. cerevisiae. In general, our data suggest that: (i hydrogen peroxide induces hormesis in a concentration- and time-dependent manner; and (ii the effect of hydrogen peroxide on yeast colony growth positively correlates with the activity of catalase that suggests the enzyme involvement in overall H2O2-induced stress response and hormetic response in yeast.

  20. INVOLVEMENT OF CATALASE IN SACCHAROMYCES CEREVISIAE HORMETIC RESPONSE TO HYDROGEN PEROXIDE

    OpenAIRE

    Ruslana Vasylkovska; Nadia Burdylyuk; Halyna Semchyshyn

    2015-01-01

    In this study, we investigated the relationship between catalase activity and H2O2-induced hormetic response in budding yeast S. cerevisiae. In general, our data suggest that: (i) hydrogen peroxide induces hormesis in a concentration- and time-dependent manner; and (ii) the effect of hydrogen peroxide on yeast colony growth positively correlates with the activity of catalase that suggests the enzyme involvement in overall H2O2-induced stress response and hormetic response in yeast.

  1. Methods for estimating lipid peroxidation: An analysis of merits and demerits

    OpenAIRE

    Devasagayam, TPA; Boloor, KK; Ramasarma, T

    2003-01-01

    Among the cellular molecules, lipids that contain unsaturated fatty acids with more than one double bond are particularly susceptible to action of free radicals. The resulting reaction, known as lipid peroxidation, disrupts biological membranes and is thereby highly deleterious to their structure and function. Lipid peroxidation is being studied extensively in relation to disease, modulation by antioxidants and other contexts. A large number of by-products are formed during this process. Thes...

  2. Lipid peroxidation and seed emergency in progenies of the yellow passion fruit plant

    OpenAIRE

    João Paulo Bestete de Oliveira; Rodrigo Sobreira Alexandre; Jacson Rondinelli da Silva Negreiros; José Carlos Lopes; Claudio Horst Bruckner

    2012-01-01

    The objective was to evaluate the percentage of emergency plantlets and lipid peroxidation in seeds of 29 half-sib progenies of yellow passion fruit (Passiflora edulis Sims.) after 24 months under storage. The experimental design was completely randomized, with four replications of 50 seeds each, from which the treatments were the progenies (1-29). The evaluation of the percent plantlet emergency was accomplished at 14 and 28 days after sowing. The lipid peroxidation of the seeds was expresse...

  3. Re-Examining the Role of Hydrogen Peroxide in Bacteriostatic and Bactericidal Activities of Honey

    OpenAIRE

    Brudzynski, Katrina; Abubaker, Kamal; St-Martin, Laurent; Castle, Alan

    2011-01-01

    The aim of this study was to critically analyze the effects of hydrogen peroxide on growth and survival of bacterial cells in order to prove or disprove its purported role as a main component responsible for the antibacterial activity of honey. Using the sensitive peroxide/peroxidase assay, broth microdilution assay and DNA degradation assays, the quantitative relationships between the content of H2O2 and honey’s antibacterial activity was established. The results showed that: (A) the average...

  4. The effect of delignification process with alkaline peroxide on lactic acid production from furfural residues

    OpenAIRE

    Yong Tang; Lingxi Bu; Lihong Deng; Liwei Zhu; Jianxin Jiang

    2012-01-01

    Furfural residues produced from the furfural industry were investigated as a substrate for lactic acid production by simultaneous saccharification and fermentation (SSF). Alkaline peroxide was used for delignification of furfural residues to improve the final lactic acid concentration. The residue was treated with 1.3% to 1.7% hydrogen peroxide at 80 °C for 1 h with a substrate concentration of 3.33%. SSF of furfural residues with different delignification degrees were carried out to eval...

  5. Oxidation of PAHs in water solutions by ultraviolet radiation combined with hydrogen peroxide

    OpenAIRE

    Dorota Olejnik; Jacek S. Miller; Stanisław Ledakowicz

    1999-01-01

    The destruction of three polycyclic aromatic hydrocarbons (PAHs): benzo[a]pyrene, chrysene and fluorene in aqueous solution using advanced oxidation process H2O2/UV was investigated. The influence of pH, initial hydrogen peroxide and radical scavenger concentrations on the reaction rate was studied. The oxidation reactions most rapidly run in neutral and acidic solution at optimal hydrogen peroxide concentration (ca. 0.01 M). The degradation of benzo[a]pyrene and chrysene follows radical reac...

  6. Key parameters when developing carbonaceous materials for catalytic wet peroxide oxidation

    OpenAIRE

    Ribeiro, Rui; Silva, Adrián; Pastrana-Martínez, Luisa; Figueiredo, José; Faria, Joaquim; Gomes, Helder

    2014-01-01

    Catalytic wet peroxide oxidation (CWPO) is an advanced oxidation process, operated using simple equipment and mild operating conditians, in which highly oxidizing hydraxyl radicaIs (HO') are generated fram the catalytic decompasition af hydrogen peroxide (H,O,) [L 2). Sinee the report of Lüeking el ai. in 1998 [3], the develapment af suitab-Ie -carbonaceous materials (without any added metal phase) for CWPO has been intensively explored [4). lhe influenee of struetUfal and surr...

  7. Orange II removal by catalytic wet peroxide oxidation using activated carbon xerogels

    OpenAIRE

    Pinho, Maria; Silva, Adrián; Fathy, Nady; Attia, Amina; Gomes, Helder; Faria, Joaquim

    2013-01-01

    Orange II is a synthetic dye widely employed in the textile industry and responsible for serious environrnentaI cancerns. Dyes like this urge the development af new technologies for the treatment af wastewaters generated in this industrial activity. Those include catalytic wet peroxide oxidation (CWPO), which is an advanced oxidation process (AOP) based on the generation of hydroxyl radicais (I-lO·) from hydrogen peroxide with tlle aid ofa suitable catalysl [I].

  8. 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

  9. The contribution of rainwater to variability in surface ocean hydrogen peroxide

    OpenAIRE

    Cooper, William J.; SALTZMAN, ERIC S.; Zika, Rod G

    1987-01-01

    Hydrogen peroxide concentrations have been determined in marine rain from the Gulf of Mexico, the western Atlantic Ocean, and one rain event off the Florida Keys. In several cases, simultaneous measurements of the concentration of H2O2 in the surface ocean were also determined. These measurements were made with the ship under way using a continuous flow sampling system with the intake at the bow. In shallow stratified layers, rain events can increase the existing hydrogen peroxide concentrati...

  10. Investigation of a novel electrocatalyst for hydrogen peroxide reduction and its application to sensing and biosensing.

    OpenAIRE

    Gonzalez Macia, Laura

    2011-01-01

    Hydrogen peroxide has, for many years, been shown to be a very important compound due to its wide and varied applications in many industrial processes as well as biological systems. Therefore, its detection and measurement represents an important analytical issue. Traditional methods such as titrimetry or spectrophotometry have more recently been displaced by electrochemical techniques, which have proven to be an inexpensive and effective means of hydrogen peroxide determination. Hydrogen ...

  11. Natural manganese deposits as catalyst for decomposing hydrogen peroxide (discussion paper)

    OpenAIRE

    Knol, A.H.; Lekkerkerker-Teunissen, K.; Van Dijk, J. C.

    2015-01-01

    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 ...

  12. Clinical presentation, lipid peroxidation intensity, and features of nitric oxide production in patients with erysipelas

    OpenAIRE

    L. I. Ratnikova; S. A. Ship

    2014-01-01

    65 patients with a diagnosis of erysipelas. Examination of the patients included an analysis of lipid peroxidation products (common polyene, diene conjugates, and conjugate ketodieny trieny, Schiff bases), antioxidant defense system (enzymatic activity of superoxide dismutase) and nitric oxide metabolites (nitrates and nitrites). It was established that imbalance between excess activated lipid peroxidation and inadequate functioning of antioxidant defense system was remained during the entire...

  13. Synthesis, crystal structure analysis, spectral IR, NMR UV-Vis investigations, NBO and NLO of 2-benzoyl-N-(4-chlorophenyl)-3-oxo-3-phenylpropanamide with use of X-ray diffractions studies along with DFT calculations

    Science.gov (United States)

    Demir, Sibel; Sarioğlu, Ahmet Oral; Güler, Semih; Dege, Necmi; Sönmez, Mehmet

    2016-08-01

    The title compound, 2-benzoyl-N-(4-chlorophenyl)-3-oxo-3-phenylpropanamide compound (C22H16NO3Cl) has been synthesized and characterized by X-ray diffraction, IR, 1H and 13C NMR and UV-Vis spectra. Optimized geometrical structure, harmonic vibrational frequencies and chemical shifts were computed using hybrid-DFT (B3LYP and B3PW91) methods and 6-311G(d,p) as the basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The calculated optimized geometries, vibrational frequencies and 1H NMR chemical shift values are in strong agreement with experimentally measured values. UV-Vis spectrum of the title compound, was also recorded and the electronic properties, such as calculated energies, excitation energies, oscillator strengths, dipole moments and frontier orbital energies and band gap energies were computed with TDDFT-B3LYP methodolgy and using 6-311G(d,p) as the basis set. Furthermore, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), natural bond orbital (NBO) and non linear optical (NLO) properties were performed by using B3LYP/6-311G(d,p) level for the title compound.

  14. Binding of N-acetyl-N '-beta-D-glucopyranosyl urea and N-benzoyl-N '-beta-D-glucopyranosyl urea to glycogen phosphorylase b: kinetic and crystallographic studies.

    Science.gov (United States)

    Oikonomakos, Nikos G; Kosmopoulou, Magda; Zographos, Spyros E; Leonidas, Demetres D; Chrysina, Evangelia D; Somsák, László; Nagy, Veronika; Praly, Jean-Pierre; Docsa, Tibor; Tóth, Béla; Gergely, Pál

    2002-03-01

    Two substituted ureas of beta-D-glucose, N-acetyl-N'-beta-D-glucopyranosyl urea (Acurea) and N-benzoyl-N'-beta-D-glucopyranosyl urea (Bzurea), have been identified as inhibitors of glycogen phosphorylase, a potential target for therapeutic intervention in type 2 diabetes. To elucidate the structural basis of inhibition, we determined the structure of muscle glycogen phosphorylase b (GPb) complexed with the two compounds at 2.0 A and 1.8 A resolution, respectively. The structure of the GPb-Acurea complex reveals that the inhibitor can be accommodated in the catalytic site of T-state GPb with very little change in the tertiary structure. The glucopyranose moiety makes the standard hydrogen bonds and van der Waals contacts as observed in the GPb-glucose complex, while the acetyl urea moiety is in a favourable electrostatic environment and makes additional polar contacts with the protein. The structure of the GPb-Bzurea complex shows that Bzurea binds tightly at the catalytic site and induces substantial conformational changes in the vicinity of the catalytic site. In particular, the loop of the polypeptide chain containing residues 282-287 shifts 1.3-3.7 A (Calpha atoms) to accommodate Bzurea. Bzurea can also occupy the new allosteric site, some 33 A from the catalytic site, which is currently the target for the design of antidiabetic drugs. PMID:11895439

  15. Synthetic protease substrate n-benzoyl-L-argininyl-p-nitroanilide activates specific binding of [3H]estradiol to a protein in rat pancreas: relationship of structure to activity

    International Nuclear Information System (INIS)

    N-benzoyl-L-argininyl-p-nitroanilide (BAN), a synthetic substrate for trypsin-like proteolytic enzymes, is a potent activator of [3H]estradiol-binding to a protein present in rat pancreas. When partially purified, this protein is almost devoid of [3H]estradiol-binding activity in the absence of an endogenous accessory factor. BAN can mimic the natural coligand in this steroid binding reaction. The effect of BAN is specific since a number of derivatives of this substance are inactive or may even inhibit steroid binding. It is unlikely that BAN exerts this stimulatory action indirectly, possibly by preventing proteolytic inactivation of the [3H]estradiol-binding protein, since preincubation of the protein in the absence of BAN resulted neither in reduced rate, nor extent, of steroid binding following BAN addition. Also, a number of protease inhibitors had no effect on the binding reaction. Of those inhibitors tested, only antipain significantly enhanced binding of [3H]estradiol, but only about 20 percent as effectively as BAN. 13 references, 1 figure, 2 tables

  16. 合成4-苯甲酰基-1,7-庚二酸二甲酯的方法改进%Process Improvement on the Synthesis of 4-Benzoyl-heptanedioic Acid Dimethyl Ester

    Institute of Scientific and Technical Information of China (English)

    康从民; 李园园; 吕英涛

    2013-01-01

    采用改进方法,苯乙酮与丙烯酸甲酯缩合制得4-苯甲酰基-1,7-庚二酸二甲酯,其结构经1H NMR和MS确证.较适宜的反应条件为:苯乙酮50 mmol,n(丙烯酸甲酯)∶n(苯乙酮)=2.5∶1.O,无水环境下,以甲醇钠为催化剂,于50℃反应24h,收率12.8%.%4-Benzoyl-heptanedioic acid dimethyl ester was prepared by condensation of acetophenone with methyl acrylate by improve method. The structure was confirmed by 1H NMR and MS. The optimal reaction conditions at 50 ℃ for 24 h were as follows: acetophenone was 50 mmol, n( methyl acrylate) : n(acetophenone) was 2. 5 :1. 0, catalyst was MeONa in water-free. The yield was 12. 8% under the optimal conditions.

  17. Thermal stabilities of various rubber vulcanization cured by sulfur, peroxide and gamma radiation

    International Nuclear Information System (INIS)

    Sulfur and peroxide-cured rubber vulcanizates of NR and EPDM were obtained by blending the elastomers with fillers, antioxidants and appropriate accelerators, followed by vulcanization at 150 - 160 degree C. Blends of the same elastomers with appropriate co-agents and additives were also cured by gamma radiation at 150 and 200 kGy. A comparison of the thermal stabilities of these vulcanizates prepared by different curing techniques has been made by thermogravimetric analysis (TGA), assessed on the basis of comparison of DTG peak maxima, temperature for loss of 50% mass and actual thermal curves. The comparison reveals that the sulfur-cured vulcanizates are less thermally stable than their peroxide-cured counterparts. This may be attributed to the presence of a stronger C-C bond in case of peroxide-cured vulcanizates compared to weaker C-S sub x-C bond in case of sulfur-cured vulcanizates. However, compared to peroxide-cured vulcanizates, radiation-cured formulations demonstrated much improved thermal stability. This may originate from the existence of more uniformly distributed crosslinks and the enhanced rate of crosslink formation in the radiation process as compared to peroxide curing. In all the formulations whether sulfur, peroxide or radiation-cured, the natural rubber vulcanizates were found to be thermally much inferior to the synthetic contender, EPDM. Influence of variation of the amount of co-agent and other additives on the thermal stabilities of formulations of radiation cured NR and EPDM vulcanizates was also investigated

  18. 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.

  19. Lipid peroxidation during n-3 fatty acid and vitamin E supplementation in humans.

    Science.gov (United States)

    Allard, J P; Kurian, R; Aghdassi, E; Muggli, R; Royall, D

    1997-05-01

    The purpose of this study was to investigate in healthy humans the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake, alone or in combination with dL-alpha-tocopherol acetate (vitamin E) supplements on lipid peroxidation. Eighty men were randomly assigned in a double-blind fashion to take daily for 6 wk either menhaden oil (6.26 g, n-3 fatty acids) or olive oil supplements with either vitamin E (900 IU) or its placebo. Antioxidant vitamins, phospholipid composition, malondialdehyde (MDA), and lipid peroxides were measured in the plasma at baseline and week 6. At the same time, breath alkane output was measured. Plasma alpha-tocopherol concentration increased in those receiving vitamin E (P < 0.0001). In those supplemented with n-3 fatty acids, EPA and DHA increased in plasma phospholipids (P < 0.0001) and plasma MDA and lipid peroxides increased (P < 0.001 and P < 0.05, respectively). Breath alkane output did not change significantly and vitamin E intake did not prevent the increase in lipid peroxidation during menhaden oil supplementation. The results demonstrate that supplementing the diet with n-3 fatty acids resulted in an increase in lipid peroxidation, as measured by plasma MDA release and lipid peroxide products, which was not suppressed by vitamin E supplementation. PMID:9168460

  20. Comparative studies on sulfur, peroxide, and radiation vulcanization of EFDM rubber

    International Nuclear Information System (INIS)

    The temperature and concentration dependence of the vulcanization characteristics and mechanical properties of epdm rubber containing various concentrations of peroxide compounds was studied. The peroxides used are Luperox Di, Luperox 500-40 Ke, peroximon Dc Sc and peroximon Dc 40 Ke. The optimum cure parameters for the different types of peroxides indicated that Luperox Di, relatively, Give the best properties among the studied peroxides. The mechanical properties of EPDM containing different concentrations of Luperox Di and vulcanized at different temperatures were compared with those of either radiation or sulfur-cured EPDM. The modulus stress and tensile strength of the Luperox Di-cured EPDM were found to increase with either increasing the temperature of vulcanization and/ or concentration of the peroxide. Moreover, the tensile strength values are much higher than those of the sulfur-cured samples, except for those with low concentration of peroxide and vulcanized at relatively low temperature. A comparable result to those of the chemically vulcanized samples was attained by the radiation- vulcanized samples containing 1 phr of crosslinking agent and irradiated to 150 KGy

  1. Environmentally acceptable effect of hydrogen peroxide on cave 'lamp-flora', calcite speleothems and limestones

    International Nuclear Information System (INIS)

    Hydrogen peroxide plus limestone fragments allows removal of organisms without corrosion of limestone and speleothem. - Mosses, algae, and cyanobacteria (lamp-flora) colonize illuminated areas in show caves. This biota is commonly removed by a sodium hypochlorite solution. Because chlorine and other deleterious compounds are released into a cave environment during lamp-flora cleansing, hydrogen peroxide was tested as an alternative agent. In a multidisciplinary study conducted in the Katerinska Cave (Moravian Karst, Czech Republic), 12 algae- and cyanobacteria taxons and 19 moss taxons were detected. The threshold hydrogen peroxide concentration for the destruction of this lamp-flora was found to be 15 vol.%. Based on laboratory experiments in stirred batch reactors, the dissolution rates of limestones and calcite speleothems in water were determined as 3.77x10-3 and 1.81x10-3 mol m-2 h-1, respectively. In the 15% peroxide solution, the limestone and speleothem dissolution rates were one order of magnitude higher, 2.00x10-2 and 2.21x10-2 mol m-2 h-1, respectively. So, the peroxide solution was recognised to attack carbonates somewhat more aggressively than karst water. In order to prevent the potential corrosion of limestone and speleothems, the reaching of preliminary peroxide saturation with respect to calcite is recommended, for example, by adding of few limestone fragments into the solution at least 10 h prior to its application

  2. Study of Lipid Peroxidation and Antioxidant Status in Preeclampsia

    Directory of Open Access Journals (Sweden)

    Alka Sontakke

    2013-07-01

    Full Text Available Background: Preeclampsia is a pregnancy spe-cific syndrome, a leading cause of maternal-fetal morbidity and mortality. Free radicals leadto lipid peroxidation which is destructive innature and has been suggested as an aetiologicalfactor in preeclampsia. Aims and Objectives:To determine the role oxidative stress and levelof antioxidants in preeclampsia by estimationof malondialdehyde (MDA (index of lipidperoxidation and antioxidants such as uric acid,vitamin C, vitamin E and superoxide dismutase(SOD in preeclampsia. Material and Meth-ods: In present study 40 non pregnant women,40 normal pregnant women and 40 preeclamp-tic women aged between 18-35 years were en-rolled. Clinically diagnosed preeclampticwomen were compared with normal pregnantwomen of same gestational age and serum wasanalyzed for serum MDA, uric acid, vitamin Eand vitamin C and SOD. Statistical analysis wasdone by ANOVA followed by Tukey’s multiplecomparison. Results: Serum MDA and uric acidlevels were significantly raised (P<0.01 inpreeclamptic women as compared to normalpregnant women and non pregnant women whileserum antioxidant vitamin E, vitamin C, andSOD levels were significantly decreased(P<0.01 in preeclamptic women and normalpregnant women as compared to non pregnantwomen. Conclusion: Increased levels of lipidperoxidation product (MDA and depletion ofantioxidants such as vitamin E, vitamin C andSOD except uric acid in women with preeclamp-sia may suggest that oxidative stress plays a keyrole in the genesis of endothelial dysfunctionand expression of preeclampsia. Adjuvantsupplementation of these antioxidants excepturic acid to the diet may minimize further pro-gression of preeclampsia.

  3. Modular advanced oxidation process enabled by cathodic hydrogen peroxide production.

    Science.gov (United States)

    Barazesh, James M; Hennebel, Tom; Jasper, Justin T; Sedlak, David L

    2015-06-16

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low concentrations of H2O2 directly in the water prior to its exposure to UV light. Following the AOP, the solution was passed through an anodic chamber to lower the solution pH and remove the residual H2O2. The effectiveness of the technology was evaluated using a suite of trace contaminants that spanned a range of reactivity with UV light and hydroxyl radical (HO(•)) in three different types of source waters (i.e., simulated groundwater, simulated surface water, and municipal wastewater effluent) as well as a sodium chloride solution. Irrespective of the source water, the system produced enough H2O2 to treat up to 120 L water d(-1). The extent of transformation of trace organic contaminants was affected by the current density and the concentrations of HO(•) scavengers in the source water. The electrical energy per order (EEO) ranged from 1 to 3 kWh m(-3), with the UV lamp accounting for most of the energy consumption. The gas diffusion electrode exhibited high efficiency for H2O2 production over extended periods and did not show a diminution in performance in any of the matrices. PMID:26039560

  4. Hydrogen peroxide induces apoptosis via a mitochondrial pathway in chondrocytes

    Science.gov (United States)

    Zhuang, Cai-ping; Liang, Qian; Wang, Xiao-ping; Chen, Tong-sheng

    2012-03-01

    The degenerative joint disease such as osteoarthritis (OA) is closely associated with the death of chondrocytes in apoptosis fashion. Hydrogen peroxide (H2O2), higher expression following acute damage in OA patients, has been shown to be up-regulated during apoptosis in a bulk of experimental models. This study was aimed to explore the mechanism of H2O2-induced rabbit chondrocytes apoptosis. Articular cartilage was biopsied from the joints of 6 weeks old New Zealand rabbits. Cell Counting Kit (CCK-8) assay was used to assess the inhibitory effect of H2O2 on cell viability. H2O2 treatment induced a remarkable reduction of cell viability. We used flow cytometry to assess the form of cell death with Annexin-V/PI double staining, and found that H2O2 treatment induced apoptosis in a dose-and time-dependent manner. Exposure of chondrocytes to 1.5 mM of H2O2 for 2 h induced a burst apoptosis that can be alleviated by N-acetyl cysteine (NAC) pretreatment, an anti-oxidant amino-acid derivative. Loss of mitochondria membrane potential (▵Ψm) was evaluated using confocal microscopy imaging and flow cytometry (FCM). H2O2 treatment induced a marked reduction of ▵Ψm, and the abrupt disappearance of ▵Ψm occurred within 5 minutes. These results indicate that H2O2 induces a rapid apoptosis via a mitochondrial pathway in rabbit chondrocytes.

  5. 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.

  6. 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

  7. 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.

  8. Diesel autothermal reforming with hydrogen peroxide for low-oxygen environments

    International Nuclear Information System (INIS)

    Highlights: • The concept of diesel reforming using hydrogen peroxide was newly proposed. • Characteristics of hydrogen peroxide was experimentally investigated. • Thermodynamically possible operating conditions were analyzed. • Catalytic performance of Ni–Ru/CGO for various diesel compounds was evaluated. • Long-term testing was successfully conducted using Korean commercial diesel. - Abstract: To operate fuel cells effectively in low-oxygen environments, such as in submarines and unmanned underwater vehicles, a hydrogen source with high hydrogen storage density is required. In this paper, diesel autothermal reforming (ATR) with hydrogen peroxide as an alternative oxidant is proposed as a hydrogen production method. Diesel fuel has higher hydrogen density than metal hydrides or other hydrocarbons. In addition, hydrogen peroxide can decompose into steam and oxygen, which are required for diesel ATR. Moreover, both diesel fuel and hydrogen peroxide are liquid states, enabling easy storage for submarine applications. Hydrogen peroxide exhibited the same characteristics as steam and oxygen when used as an oxidant in diesel reforming when pre-decomposition method was used. The thermodynamically calculated operating conditions were a steam-to-carbon ratio (SCR) of 3.0, an oxygen-to-carbon ratio (OCR) of 0.5, and temperatures below 700 °C to account for safety issues associated with hydrogen peroxide use and exothermic reactions. Catalytic activity and stability tests over Ni–Ru (19.5–0.5 wt.%)/Ce0.9Gd0.1O2−x were conducted using various diesel compounds. Furthermore, long-term diesel ATR tests were conducted for 200 h using Korean commercial diesel. The degradation rate was 3.67%/100 h without the production of ethylene

  9. 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. PMID:26811546

  10. 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

  11. 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.

  12. 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

  13. Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

    Science.gov (United States)

    He, S. Z.; Chen, Z. M.; Zhang, X.; Zhao, Y.; Huang, D. M.; Zhao, J. N.; Zhu, T.; Hu, M.; Zeng, L. M.

    2010-09-01

    For the 2008 Beijing Olympic Games full-scale control (FSC) of atmospheric pollution was implemented to improve the air quality from 20 July to 20 September 2008, resulting in a significant decrease in the emission of pollutants in urban Beijing, especially vehicular emissions. The combination of reduced emissions and weather condition changes provided us with a unique opportunity to investigate urban atmospheric chemistry. Hydrogen peroxide (H2O2) and organic peroxides play significant roles in atmospheric processes, such as the cycling of HOx radicals and the formation of secondary sulfate aerosols and secondary organic aerosols. We measured atmospheric H2O2 and organic peroxides in urban Beijing, at the Peking University campus, from 12 July to 30 September, before and during the FSC. The major peroxides observed were H2O2, methyl hydroperoxide (MHP), and peroxyacetic acid (PAA), having maximal mixing ratios of 2.34, 0.95, and 0.17 ppbv (parts per billion by volume), respectively. Other organic peroxides were detected occasionally, such as bis-hydroxymethyl hydroperoxide, hydroxymethyl hydroperoxide, ethyl hydroperoxide, and 1-hydroxyethyl hydroperoxide. On sunny days the concentrations of H2O2, MHP, and PAA exhibited pronounced diurnal variations, with a peak in the afternoon (1500-1900) and, occasionally, a second peak in the evening (2000-0200). The night peaks can be attributed to local night production from the ozonolysis of alkenes, coupled with the reaction between NO3 radicals and organic compounds. Sunny-day weather dominated during 16-26 July, and we found that the concentrations of H2O2, MHP, and PAA increased strikingly on 22-26 July, compared with the concentrations during 16-19 July. This effect was mainly attributed to the NOx (NO and NO2) decline because of the FSC, due to (i) the suppressing effect of NO and NO2 on the production of peroxides and (ii) the indirect effect of reduced NOx on the concentration of peroxides via O3 production in the

  14. Hydrogen embrittlement of 4340 steel due to condensation during vaporized hydrogen peroxide treatment

    International Nuclear Information System (INIS)

    Research highlights: → Exposure of low-alloy, high strength 4340 steel to water vapor with 500 or 1000 ppm hydrogen peroxide for 4.8 h does not lead to hydrogen embrittlement per ASTM 519E-06. → Exposure of low-alloy, high strength 4340 steel to 35 wt.% H2O2 in water for 4.8 h does not lead to hydrogen embrittlement per ASTM 519E-06. → Operation of vaporized hydrogen peroxide decontamination chambers at 1300 or 1600 ppm hydrogen peroxide concentration can lead to significant condensation with very high concentrations of H2O2 (50-75 wt.% H2O2) in the condensed liquid → Exposure of low-alloy, high strength 4340 steel to vaporized hydrogen peroxide treatments at 1300 or 1600 ppm hydrogen peroxide concentration for 4.8 h led to extensive condensation of high H2O2 concentration (∼64 wt.% H2O2) in the process chamber and hydrogen embrittlement of the steel per ASTM 519E-06. - Abstract: Hydrogen peroxide vapor has been proposed as a sterilant/decontaminant for usage in buildings and transportation vehicles including emergency vehicles, buses, trains and aircraft. Although the efficacy of the process has been demonstrated, questions regarding the compatibility of vaporized hydrogen peroxide treatments with the many diverse materials of construction have been raised. This paper presents results on the embrittlement of high strength AISI 4340 steel as a result of condensation of the vapor during exposure to vaporized hydrogen peroxide. Notched four point bending samples of AISI 4340 steel were tested using the standard test methods of ASTM F519-06 to quantify susceptibility to hydrogen embrittlement in this aggressive service environment. No embrittlement effects were observed for samples exposed to strictly vapor phase hydrogen peroxide for concentrations up to 1000 ppm H2O2 and exposure times of 4.8 h. Higher concentrations of 1300 and 1600 ppm H2O2 led to the condensation of the vapor throughout the process chamber and brittle fracture of samples. These results

  15. Strategies for designing supported gold-palladium bimetallic catalysts for the direct synthesis of hydrogen peroxide.

    Science.gov (United States)

    Edwards, Jennifer K; Freakley, Simon J; Carley, Albert F; Kiely, Christopher J; Hutchings, Graham J

    2014-03-18

    Hydrogen peroxide is a widely used chemical but is not very efficient to make in smaller than industrial scale. It is an important commodity chemical used for bleaching, disinfection, and chemical manufacture. At present, manufacturers use an indirect process in which anthraquinones are sequentially hydrogenated and oxidized in a manner that hydrogen and oxygen are never mixed. However, this process is only economic at a very large scale producing a concentrated product. For many years, the identification of a direct process has been a research goal because it could operate at the point of need, producing hydrogen peroxide at the required concentration for its applications. Research on this topic has been ongoing for about 100 years. Until the last 10 years, catalyst design was solely directed at using supported palladium nanoparticles. These catalysts require the use of bromide and acid to arrest peroxide decomposition, since palladium is a very active catalyst for hydrogen peroxide hydrogenation. Recently, chemists have shown that supported gold nanoparticles are active when gold is alloyed with palladium because this leads to a significant synergistic enhancement in activity and importantly selectivity. Crucially, bimetallic gold-based catalysts do not require the addition of bromide and acids, but with carbon dioxide as a diluent its solubility in the reaction media acts as an in situ acid promoter, which represents a greener approach for peroxide synthesis. The gold catalysts can operate under intrinsically safe conditions using dilute hydrogen and oxygen, yet these catalysts are so active that they can generate peroxide at commercially significant rates. The major problem associated with the direct synthesis of hydrogen peroxide concerns the selectivity of hydrogen usage, since in the indirect process this factor has been finely tuned over decades of operation. In this Account, we discuss how the gold-palladium bimetallic catalysts have active sites for the

  16. Correlation among lung damage after radiation, amount of lipid peroxides, and antioxidant enzyme activities

    International Nuclear Information System (INIS)

    The correlation between lipid peroxidation and morphologic changes was examined in Sprague-Dawley rat lungs after 30 Gy single thoracic radiation. The rats were sacrificed every week until the end of the fifth week after radiation. The left lungs were used for the measurement of lipid peroxides and antioxidant enzymes activities. The right lungs were examined by light and electron microscopy. Amounts of lung lipid peroxides were within normal limits, and no cellular degenerative changes were observed in the lungs except for subendothelial and interstitial edema 2 weeks after radiation. Lipid peroxides drastically increased and marked degenerative cellular changes such as edematous swelling, vacuolation, and destruction of cell membranes occurred in the alveolar septa following the third week after radiation. The activities of catalase were significantly higher during the period from the second to the fifth week and those of superoxide dismutase and glutathione peroxidase increased at the end of the fifth week. Our results demonstrated that the acceleration of lipid peroxidation was well correlated with the morphologic expression of cell injury in the irradiated lungs

  17. Compositional Factors that Influence Lipid Peroxidation in Beef Juice and Standard Sausages.

    Science.gov (United States)

    Yi, Gu; Haug, Anna; Nordvi, Berit; Saarem, Kristin; Oostindjer, Marije; Langsrud, Øyvind; Egelandsdal, Bjørg

    2015-12-01

    In order to identify how different additives influenced lipid peroxidation formation, a sausage only using beef juice as pigment source and a standard beef-pork meat sausage were studied. The effects of different additives, including fish oil, myoglobin, nitrite, clove extract, and calcium sources on oxidation and sensory properties were examined. Both sausage systems were stored in 3 different manners prior to testing: (1) frozen immediately at -80 °C; (2) chilled stored for 2.5 weeks followed by fluorescent light illumination at 4 °C for another 2 wk; (3) frozen at -20 °C for 5 mo. The frozen group 3 showed the highest peroxide formation and thiobarbituric acid reactive substances (TBARS) for both sausage systems. Unpolar peroxides dominated in both systems. The clove extract could offset the peroxide formation from myoglobin/beef juice and/or fish oil, but the addition of clove flavor was recognized by the sensory panelists. Calcium addition reduced lipid peroxide formation. Added nitrite and fish oil seemed to interact to stimulate nitroso-myoglobin formation. Nitrite was identified to interact with clove addition and thereby, relatively speaking, increased TBARS. The 2 sausage systems generally ranked the additives similarly as pro- and antioxidants. PMID:26579877

  18. Protective Effect of Cinnamomum tejpata on Lipid Peroxide Formation in Isolated Rat Liver Homogenate

    Directory of Open Access Journals (Sweden)

    Vandana Gupta

    2010-07-01

    Full Text Available Restrictions on the use of synthetic antioxidants are being imposed because of their toxic properties.The present study is the continuation of a program aimed at investigation on antioxidant activity of extractsfrom medicinal plants and to identify alternative natural and safe sources of food antioxidant especially fromplant origin. Free radicals are involved in more than 50 diseases. Day to day researchers are adding morenumber of diseases to the list. In this report the anti-peroxidative effect of alcoholic extract of Cinnamomumtejpata has been studied in rat liver homogenate. Ferrous sulphate has been used as inducer to induce lipid peroxidation. On the basis of results, it could be concluded that TBARS production in normal condition group isvery slow and in FeSO4 treated groups, it is very high. Initiation of lipid peroxidation by ferrous sulphate takesplace either through ferryl- perferryl com plex or through OH Radical from Fenton’s reaction. Effect of differentconcentrations of ferrous sulphate for induction of lipid peroxidation in rat liver homogenate was studied. Dosedependent increase in lipid peroxidation was found. Results revealed that at lower doses the rate of formationof TBARS is slow , which increased with dose. Significant and moderate results were found from 0.40 mM to0.80 mM of ferrous sulphate.

  19. Mushroom extract protects against hydrogen peroxide-induced toxicity in hepatic and neuronal human cultured cells.

    Science.gov (United States)

    Guizani, Nejib; Waly, Mostafa I

    2012-11-15

    Hydrogen peroxide is an oxidative stress agent that is associated with depletion of intracellular glutathione and inhibition of antioxidant enzymes in different cell lines. Consumption of antioxidant-rich foods reduces cellular oxidative stress and its related health problems. This study aimed to assess the antioxidant properties of mushroom, Agaricus bisporous cultivar extract, against hydrogen peroxide induced oxidative stress in cultured human hepatic (HepG2) and neuronal (SH-SY5Y) cells. In this study, hydrogen peroxide caused significant oxidative stress in HepG2 and SH-SY5Y cells as demonstrated by glutathione depletion, impairment of total antioxidant capacity and inhibition of antioxidant enzymes (glutathione peroxidase, catalase and superoxide dismutase). Agaricusbisporous extract ameliorated the observed hydrogen peroxide-induced oxidative cellular insult as indicated by restoring the activity of glutathione and the assayed antioxidant enzymes to control levels. The results suggest that mushroom extract as antioxidant properties and protects against the oxidative stress induced by hydrogen peroxide-in cultured human hepatic and neuronal cells. PMID:24261122

  20. Analysis of the kinetics of lipid peroxidation in terms of characteristic time-points.

    Science.gov (United States)

    Pinchuk, Ilya; Lichtenberg, Dov

    2014-02-01

    Measuring peroxidation of aggregated lipids in model systems (liposomes, micelles, emulsions or microemulsions) as well as in samples of biological origin ex vivo (isolated lipoproteins, blood sera or plasma) is widely used in medical and biological investigations, to evaluate the oxidative stress, antioxidants' efficiency and lipid oxidizability in different pathophysiological states. To avoid possible artifacts, such investigations must be based on the time course of peroxidation (i.e. on kinetic studies). To be able to compare complex kinetic profiles, it is important to characterize them in terms of mechanistically meaningful and experimentally unequivocal parameters. In this review, we characterize the typically observed continuous kinetic profiles in terms of a limited number of characteristic time-points (both commonly used and additional time-points and their combinations) that can be derived from experimental time-dependencies. The meaning of each of the experimentally observed characteristic parameters is presented in terms of rate constants and concentrations, derived on the basis of mechanistic considerations. Theoretical expressions for these characteristic parameters are based on a model that includes both the inhibited peroxidation and the uninhibited peroxidation occurring after consumption of the antioxidant(s). Comparison between theoretically predicted dependencies and experimental data support our treatment considered with special emphasis on transition metals-induced peroxidation of lipoproteins. PMID:24333462

  1. Reactivity of lignin and lignin models towards UV-assisted peroxide

    International Nuclear Information System (INIS)

    The comparative reactivities of a series of guaiacyl and syringyl lignin model compounds and their methylated analogues towards alkaline peroxide and UV-alkaline peroxide were investigated. The overall reaction was followed by monitoring the reduction of the substrate as a function of time, and in every case, the reaction showed pseudo-first-order kinetics. The reaction rates of most lignin models having identical sidechains with alkaline peroxide and with UV-alkaline peroxide were in the order syringyl guaiacyl 3,4,5-trimethoxyphenyl veratryl. Thus phenols react faster than their methyl ethers, and an extra ortho methoxyl group promotes the reaction. Lignin models possessing electron-donating sidechains had generally higher reaction rates than those with electron-withdrawing sidechains. The reaction rates of the series of benzoic acids were 2-4 times higher at pH 11 than at pH 5. UV-peroxide degradation of a eucalypt kraft lignin was faster than that of a pine kraft lignin, and degradation was 1.4-1.6 times faster at pH 11 than at pH 5. The data are consistent with the formation of higher amounts of reactive radicals under alkaline conditions, and aromatic rings with greater electronegativities promoting reactions with the radicals

  2. Role of lipid peroxidation and oxidative stress in 3-methylindole pneumotoxicity

    International Nuclear Information System (INIS)

    The cytochrome P-450-catalyzed metabolism of 3-methylindole (3-MI) results in acute lung injury in ruminants and horses. Experiments were conducted to determine the role of lipid peroxidation and oxidative stress in 3-MI pneumotoxicity in goats. Goats were given methylethylketone peroxide (MEKP), a potent peroxidant, 3-MI, indole, or cremophor-EL vehicle. The levels of shortchain hydrocarbons in expired air were measured for 6 hours post-dosing by gas chromatography. Exhaled hydrocarbons increased 20 to 30 fold within 1 hour in goats given MEKP. No significant changes were seen in goats given 3-Mi, indole or cremophor-EL. Levels of thiobarbituric acid-reactive substances, an indicator of lipid peroxidation, were significantly increased in lung tissue from goats given MEKP. In goats given 3-MI, indole or cremophor-EL, the levels were not significantly different from each other. Goats were killed at 6 hours post-dosing and examined post mortem. Bronchiolar epithelial necrosis was seen in goats given 3-MI but there were not lung lesions in other groups. The role of oxygen radicals in 3-MI pneumotoxicity was examined in a goat lung explant system using 51Cr release as an indicator of cytotoxicity. The results of these studies provide no evidence to support the view that 3-MI pneumotoxicity involves lipid peroxidation or oxidative stress as a result of formation of oxygen or xenobiotic radicals

  3. Role of peroxidation and heme catalysis in coloration of raw meat

    Directory of Open Access Journals (Sweden)

    Alexander G. Shleikin

    2014-06-01

    Full Text Available It is known, that lipid peroxidation is one of the main factors limiting the ąuality and acceptability of meat and other animal tissues. The current data conceming connection of heme and peroxidation were summarized and analysed here. The muscle food compounds that are most influenced by oxidative processes include unsaturated fatty acids of lipids, amino acids of proteins and heme groups of pigments. Heme proteins and particularly myoglobin are abundant in muscle tissues. Meat colour is primarily influenced by the concentration and chemical State of heme pigments, myoglobin and hemoglobin. Oxygenated myoglobin oxidized to the brown metmyoglobin form and its accumulation is highly correlated with progress of lipid peroxidation. Heme proteins such as hemoglobin or myoglobin accelerate the decomposition of hydroperoxides to free radicals. Metmyoglobin possesses «pseudoperoxidase» activity and catalyzes the oxidation of various compounds following the reaction with hydrogen peroxide. The reaction between hydrogen peroxide and metmyoglobin results in the formation of two active hypervalent myoglobin species, perferrylmyoglobin (*MbFelv=0 and ferrylmyoglobin (MbFelv=0, which participate in lipid oxidation catalysis. Both MbFeIV=0 and *MbFelv=0 are deactivated in the presence of reducing agents, whose naturę determines the overall effect of the pseudoperoxidase cycle. Hypothesis can be put forward that loss of cellular antioxidants might precede the rise of peroxidase-like activity, thus being a sign of incipient discoloration of meats and muscle components of foods.  

  4. Determination of serum aluminum, platelet aggregation and lipid peroxidation in hemodialyzed patients

    Directory of Open Access Journals (Sweden)

    T.J.C. Neiva

    2002-03-01

    Full Text Available Aluminum (Al3+ overload is frequently associated with lipid peroxidation and neurological disorders. Aluminum accumulation is also reported to be related to renal impairment, anemia and other clinical complications in hemodialysis patients. The aim of the present study was to determine the degree of lipid peroxidation, platelet aggregation and serum aluminum in patients receiving regular hemodialytic treatment. The level of plasma lipid peroxidation was evaluated on the basis of thiobarbituric acid reactive substances (TBARS. Mean platelet peroxidation in patients undergoing hemodialysis was significantly higher than in normal controls (2.7 ± 0.03 vs 1.8 ± 0.06 nmol/l, P<0.05. Platelet aggregation and serum aluminum levels were determined by a turbidimetric method and atomic absorption spectrophotometry, respectively. Serum aluminum was significantly higher in patients than in normal controls (44.5 ± 29 vs 10.8 ± 2.5 µg/l, P<0.05. Human blood platelets were stimulated with collagen (2.2 µg/ml, adenosine diphosphate (6 µM and epinephrine (6 µM and showed reduced function with the three agonists utilized. No correlation between aluminum levels and platelet aggregation or between aluminum and peroxidation was observed in hemodialyzed patients.

  5. Induction of lipid peroxidation by hexachlorocyclohexane, dieldrin, TCDD, carbon tetrachloride, and hexachlorobenzene in rats

    Energy Technology Data Exchange (ETDEWEB)

    Goel, M.R.; Shara, M.A.; Stohs, S.J.

    1988-02-01

    Hexachlorobenzene (HCB), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), hexachlorocyclohexane (HCCH) and dieldrin are all halogenated lipophilic environmental contaminants. A common biologic property of these compounds is their ability to induce hepatic microsomal drug metabolizing enzymes. Furthermore, exposure of laboratory animals to these xenobiotics elicits a number of similar effects including porphyria, hypothyroidism, a wasting syndrome and lethality. Perturbation of membrane lipids and lipid peroxidation may be responsible for at least part of the toxic effects of HCCH. TCDD has been shown to induce lipid peroxidation in hepatic and extrahepatic tissues. Based on the similar toxic manifestations of HCB, HCCH, TCDD and dieldrin, the authors have examined the effects of these xenobiotics on hepatic lipid peroxidation following an acutely toxic dose. Lipid peroxidation was assessed by determining the content of thiobarbituric acid reactive substance (TBARS) in the liver, employing malondialdehyde as the standard. Animals were also treated with carbon tetrachloride, a well know inducer of lipid peroxidation, as a positive control. Furthermore, the ability of these xenobiotics to inhibit selenium dependent glutathione peroxidase (GSHPX) activity was determined.

  6. Prediction of the thermal decomposition of organic peroxides by validated QSPR models

    International Nuclear Information System (INIS)

    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

  7. Influence of hydrogen peroxide bleaching gels on color, opacity, and fluorescence of composite resins.

    Science.gov (United States)

    Torres, C R G; Ribeiro, C F; Bresciani, E; Borges, A B

    2012-01-01

    The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (pColor changes were significant for different tested bleaching therapies (pcolor change observed for 35% hydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (pbrand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration. PMID:22433032

  8. Characterization and thermal stability of uranium peroxides by thermogravimetry and differential scanning calorimetry

    International Nuclear Information System (INIS)

    The characterization and thermal behaviour of uranium peroxide samples prepared by precipitation with hydrogen peroxide from uranyl nitrate solution is described. The latter was obtained by dissolution of ammonium diuranate and ammonium uranyl tricarbonate. TG and DTG curves were recorded in the temperature range from room temperature to 7000C. DSC curves were recorded from room temperature to 6000C. The heating rate was 50C/min. Based upon the DTG curves of a great number of samples, the uranium peroxides were classified in five groups. The collected information was used to recognise the temperature at which the peroxide decomposes and to know its sequential conversion to UO3 and U3O8, the evolution of molecules of water of crystallization and absorption, and the elimination of occluded nitrate ions. The results allowed to conclude that no NH+4 nor H2O2 molecules were occluded by uranium peroxide. The stoichiometric composition of representative samples for the five groups is indicated. (Author)

  9. Correlation of Lipid Peroxidation with Glycated Haemoglobin Levels in Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Varashree BS

    2011-07-01

    Full Text Available Reactive oxygen species are crucial to normal biological processes; they are potentially dangerous and are commonly referred to as prooxidants. The reactive oxygen intermediates can cause direct cellular injury by including lipid and protein peroxidation and damage to nucleic acid. The polyunsaturated fatty acids present in the cells are vulnerable to free radicals causing lipid peroxidation. Determination of Malondialdehyde (MDA by using thiobarbituric acid is used as an index of the extent of lipid peroxidation. This study was done to know if lipid peroxidation correlated with the glycated haemoglobin levels. Diabetic status was assessed by estimating fasting blood sugar and glycated haemoglobin level while oxidant stress was evaluated by estimating erythrocyte MDA levels. The lipid peroxidation in erythrocyte lysates was significantly increased in diabetic individuals compared to controls (p<0.001. The result of this study indicates that in diabetic individuals are more prone to oxidative stress and glycated haemoglobin is a marker in evaluating the long term glycemic status in diabetic individuals.

  10. Promotion of radiation peroxidation in models of lipid membranes by caesium and rubidium counter-ions: micellar linolenic acids

    International Nuclear Information System (INIS)

    Caesium and rubidium counter-ions increase peroxidation in irradiated micelles of linoleic (18 : 2) and linolenic (18 :3) acids. The effect was specific to Cs+ and Rb+ in the alkali metal series. The effect was independent of the salts used (Cl-, NO3-, Cl04-) and, therefore, independent of the chaotropic nature, and reactivity with hydroxyl radicals of Cl-, NO3- and ClO4-. The promotion of peroxidation by Cs+ and Rb+ is interpreted in terms of their effect on fatty acid micelle structure. The dependence of radiation peroxidation on lipid structure in the micelles may be significant for studies of peroxidation in highly structured cell membranes. (author)

  11. Kinetic Study on Nucleophilic Displacement Reactions of Y-Substituted-Phenyl 2-Methylbenzoates with Cyclic Secondary Amines in Acetonitrile: Effects of Modification of 2-MeO in Benzoyl Moiety by 2-Me on Reactivity and Reaction Mechanism

    International Nuclear Information System (INIS)

    The second-order rate constants (kN) have been measured spectrophotometrically for nucleophilic substitution reactions of Y-substituted-phenyl 2-methylbenzoates (6a-e) with a series of cyclic secondary amines in MeCN at 25.0 ± 0.1 .deg. C. Comparison of the kN values for the reactions of 4-nitrophenyl 2-methylbenzoate (6d) with those reported previously for the corresponding reactions of 4-nitrophenyl 2-methoxybenzoate (5) reveals that 6d is significantly less reactive than 5, indicating that modification of 2-MeO in the benzoyl moiety of 5 by 2-Me (i. e., 5 → 6d) causes a significant decrease in reactivity. This supports our previous report that aminolysis of 5 proceeds through a six-membered cyclic intermediate, which is highly stabilized through intramolecular H-bonding interactions. The Brφnsted-type plot for the reactions of 6d with a series of cyclic secondary amines is linear with βnuc = 0.71, which appears to be a lower limit of βnuc for a stepwise mechanism with breakdown of an intermediate (T±) being rate-determining step (RDS). The Brφnsted-type plot for the reactions of 6a-e with piperidine is curved, i. e., the slope of Brφnsted-type plot (βlg) decreases from -1.05 to -0.41 as the leaving-group basicity decreases. The nonlinear Brφnsted-type plot has been taken as evidence for a stepwise mechanism with a change in RDS (e. g., from the k2 step to the k1 process as the leaving-group basicity decreases). Dissection of kN into the microscopic rate constants associated with the reactions of 6a-e with piperidine (e. g., k1 and k2/k-1 ratio) also supports the proposed mechanism

  12. Synthesis, Characterization And Antitumor Activity Of Copper(II Complexes, [CuL2] [HL1-3=N,N-Diethyl-N'-(R-BenzoylThiourea (R=H, o-Cl and p-NO2

    Directory of Open Access Journals (Sweden)

    Evgenia Spodine

    2004-01-01

    Full Text Available The copper (II complexes (CuL2 were prepared by reaction of Cu(CH3COO2 with the corresponding derivatives of acylthioureas in a Cu:HL molar ratio of 1:2. Acylthiourea ligands, N,N-diethyl-N'-(R-benzoyl thiourea (HL1-3 [R=H, o-Cl and p-NO2] were synthesized in high yield (78-83% and characterized by elemental analysis, infrared spectroscopy, 1H and 13C NMR spectroscopy. The complexes CuL2 were characterized by elemental analysis, IR, FAB(+-MS, magnetic susceptibility measurements, EPR and cyclic voltammetry. The crystal structure of the complex Cu(L22 shows a nearly square-planar geometry with two deprotonated ligands (L coordinated to CuII through the oxygen and sulfur atoms in a cis arrangement. The antitumor activity of the copper(II complexes with acylthiourea ligands was evaluated in vitro against the mouse mammary adenocarcinoma TA3 cell line. These complexes exhibited much higher cytotoxic activity (IC50 values in the range of 3.9-6.9 μM than their corresponding ligands (40-240 μM, which indicates that the coordination of the chelate ligands around the CuII enhances the antitumor activity and, furthermore, this result confirmed that the participation of the nitro and chloro substituent groups in the complex activities is slightly relevant. The high accumulation of the complexes Cu(L22 and Cu(L32 in TA3 tumor cells and the much faster binding to cellular DNA than Cu(L12 are consistent with the in vitro cytotoxic activities found for these copper complexes.

  13. Dissolution kinetics of U3Si2 particles in alkaline hydrogen peroxide

    International Nuclear Information System (INIS)

    Nonproliferation concerns leading to the conversion from high- to low-enriched uranium sparked interest in U3Si2 dispersion targets as an option for 99Mo production. Dissolution of irradiated targets is an important step in recovering fission-product 99Mo. Alkaline hydrogen peroxide solutions dissolved U3Si2 particles in an open batch reactor; samples were analyzed for total peroxide and uranium concentrations as functions of time and temperature. Dissolution rates are highest at 1 to 1.5 M NaOH and change little for initial base concentrations from 0.5 to 2.5 M NaOH, indicating relatively robust process conditions. Uranium dissolution rates depend most strongly on the equilibrium concentration of the peroxyl ion (O2H-), an equilibrium product of hydrogen peroxide (H2O2) and hydroxyl ion (OH-). Temperature and equilibrium concentrations of O2H- and OH- are included in a uranium dissolution rate model

  14. Investigation of the oxidation of hydrochloric acid in scrubbing solutions containing hydrogen peroxide

    International Nuclear Information System (INIS)

    Oxidation and absorption of nitrogen oxides by a solution containing sulphuric, nitric acids and hydrogen peroxide have been investigated. The oxidation of nitric oxide is dependent among others on hydrogen peroxide concentration total acidity and temperature. The absorption of N O2 by the scrubbing solution (H2 S O4,H N O3 and H2 O2) in all cases studied is not less than 98%. The oxidation of chloride into chlorine gas increases as the concentration of each of hydrochloric acid, nitric oxide and nitric acid increases. On the other hand as the concentration of hydrogen peroxide increases the amount of chlorine gas decreases. The results show that the oxidation of chloride into chlorine gas is mainly due to nitrogen dioxide. 7 fig., 2 tab

  15. Platinum-rare earth cathodes for direct borohydride-peroxide fuel cells

    Science.gov (United States)

    Cardoso, D. S. P.; Santos, D. M. F.; Šljukić, B.; Sequeira, C. A. C.; Macciò, D.; Saccone, A.

    2016-03-01

    Hydrogen peroxide (H2O2) is being actively investigated as an oxidant for direct borohydride fuel cells. Herein, platinum-rare earth (RE = Sm, Dy, Ho) alloys are prepared by arc melting and their activity for hydrogen peroxide reduction reaction (HPRR) is studied in alkaline media. Cyclic voltammetry and chronoamperometry measurements show that Pt-Sm electrode displays the highest catalytic activity for HPRR with the lowest activation energy, followed by Pt-Ho, while Pt-Dy alloys show practically no activity. Laboratory direct borohydride-peroxide fuel cells (DBPFCs) are assembled using these alloys. The DBPFC with Pt-Sm cathode gives the highest peak power density of 85 mW cm-2, which is more than double of that obtained in a DBPFC with Pt electrodes.

  16. Oxidation of uranium dioxide by hydrogen peroxide in sulfuric acid medium

    International Nuclear Information System (INIS)

    The oxidation of uranium dioxide by hydrogen peroxide in sulfuric acid medium was studied. It was found that in the UO2-H2O2-Fe/sup (II,III)/-H2SO4 system, the value of the oxidation potential (OP) is determined by the amount of Fe/sup (III)/ ions formed as the result of the oxidation of ferrous oxide by hydrogen peroxide. At normal temperature, H2O2 displays its oxidizing activity with respect to uranium dioxide at OP values of 500-550 mV, and at elevated temperature (40-600C) and in the presence of iron ions, at 400-450 mV. In a wide range of pH values, hydrogen peroxide as oxidizing agent considerably surpasses oxidizing agents such as nitrous acid, manganese dioxide, manganates, and permanganates. The process proceeds vigorously not only with the participation of iron ions, but also in their absence

  17. CuO impregnated activated carbon for catalytic wet peroxide oxidation of phenol

    International Nuclear Information System (INIS)

    This paper presents an original approach to the removal of phenol in synthetic wastewater by catalytic wet peroxide oxidation with copper binding activated carbon (CuAC) catalysts. The characteristics and oxidation performance of CuAC in the wet hydrogen peroxide catalytic oxidation of phenol were studied in a batch reactor at 80 deg. C. Complete conversion of the oxidant, hydrogen peroxide, was observed with CuAC catalyst in 20 min oxidation, and a highly efficient phenol removal and chemical oxygen demand (COD) abatement were achieved in the first 30 min. The good oxidation performance of CuAC catalyst was contributed to the activity enhancement of copper oxide, which was binding in the carbon matrix. It can be concluded that the efficiency of oxidation dominated by the residual H2O2 in this study. An over 90% COD removal was achieved by using the multiple-step addition in this catalytic oxidation.

  18. Synthesis, characterization, and differentiation of high energy amine peroxides by MS and vibrational microscopy

    Science.gov (United States)

    Peña-Quevedo, Alvaro J.; Mina-Calmide, Nairmen; Rodríguez, Nelmary; Nieves, Deborah; Cody, Robert B.; Hernández-Rivera, Samuel P.

    2006-05-01

    Synthesis and characterization of hexamethelene triperoxide diamine (HMTD), tetramethylene diperoxide dicarbamide (TMDD) and tetramethylene diperoxide acetamide (TMDA) using GC-MS, HPLC-MS, FT-IR and Raman Microscopy has been carried out. The study also centered in the synthesis and characterization of other cyclic amine peroxides, including and different forms of caged peroxides from other diaminoalkanes. Interest also was given to the secondary products of all syntheses and the effect of temperature in the composition mixtures of the preparations. Differentiation spectroscopy and spectrometry studies were also conducted. In these studies the differences in the ν(O-O), ν(N-C), ν(N-H), ν(C-O), δ(CH 3-C) and δ(C-O) bands for Raman and IR were established. For the GC/MS spectrometric studies retention times and fragmentation patterns for GC-MS and GC-FT-IR useful in amine peroxide differentiation were also established.

  19. [Effect of shengmaisan on serum lipid peroxidation in acute viral myocarditis].

    Science.gov (United States)

    Zhao, M H; Rong, Y Z; Lu, B J

    1996-03-01

    The effect of Shengmaisan (SMS) on 62 acute viral myocarditis patients and its peroxidation damage was studied. The results revealed that the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in blood were decreased and the content of malondialdehyde (MDA) in plasma was increased in acute viral myocarditis patients in comparison with the healthy controls (P SMS group and placebo group. After treatment, both SOD and GSH-Px activities were increased and the level of MDA decreased (P SMS group, while those in placebo group were not changed (P < 0.05). The results suggested that the myocardial damage of viral myocarditis is closely related with lipid peroxidation SMS acts as an effective free radical scavenger and anti-lipid peroxidation drug. SMS could prevent the damage of myocardia and might be taken as one of the effective therapeutic methods in treatment of acute viral myocarditis. PMID:9208534

  20. [Immune system function and lipid peroxidation processes in protracted forms of pneumonia].

    Science.gov (United States)

    Efimov, V V; Blazhko, V I; Gladchenko, A R

    1989-04-01

    The authors studied the characteristic features of cellular and humoral immunity as well as the intensity of free-radical lipid peroxidation in 74 patients with acute and protracted course of acute pneumonia. A close relationship was established between immune disorders at the level of the regulatory link and the activity of peroxidation of lipids during transformation of acute pneumonia into protracted. It is shown that the content of products of lipid peroxidation in erythrocytes during the first days of the disease may be a well-informative criterion reflecting the character of course of the inflammatory process in the lungs and adequate immune response. This may be used for the prognosis of protracted forms of pneumonia. PMID:2756694

  1. State changes both lipids peroxide oxidation and antioxidant protection under low radiation doses in experiment

    International Nuclear Information System (INIS)

    Research actuality of radiation effect of low insensitivity on biological objects and criteria elaboration for estimation of unfavorable factors influences of different levels of bio-object organization shows that there is the increasing the oncological patients in Stepnogorsk, Shantobe and other regions of Akmola oblast during the last time. The goal of ths work is to study the level of lipids peroxide oxidation (LPO) in condition of low radiation doses. Insensitivity of LPO was evaluated by content of malonyl dialdegide as a secondary product of lipids peroxide oxidation and by definition of catalase activity as enzyme of antioxidant protection. The were no reliable changes of LPO content in control groups after 4 weeks and catalase activity in comparison with animal groups after two weeks. We consider that it is necessary to research LPO dynamics in the further period, as well as testing of analysis of superoxides mutase erythrocytes activity and general peroxidation blood activity

  2. Ultrafast Shock Interrogation of Hydrogen Peroxide/Water Mixtures: Thermochemical Predictions of Shock Condition Chemistry

    Science.gov (United States)

    Zaug, Joseph; Armstrong, Michael; Bastea, Sorin; Carter, Jeffrey; Kuo, I.-F. William; Crowhurst, Jonathan; Grant, Christian

    2012-02-01

    Hydrogen peroxide is a powerful oxidizer and its concentrated aqueous solutions exhibit very high reactivity, even sustaining detonation under strong enough confinement. Due to its simple composition and basic expected decomposition kinetics hydrogen peroxide is very suitable for studying the interplay of high pressures, temperatures and reactivity and their effect on the equation of state, particularly at the boundary between detonating and non-detonating behavior. To this end we performed speed of sound and picosecond time resolved shock measurements on solutions of hydrogen peroxide of concentrations from 30 to 90 percent, and analyzed the results in terms of common assumptions of chemical equilibrium in reactive fluid mixtures. Experimental shock states were achieved up to a maximum pressure of 20 GPa with corresponding shock velocities of 6-7 km/sec.

  3. Asbestos-catalyzed oxidation of benzo(a)pyrene by superoxide-peroxidized microsomes

    International Nuclear Information System (INIS)

    Asbestos and benzo(a)pyrene [B(a)P] are ubiquitous in our environment and both are recognized as causal factors for cancer in man and animals. In vitro studies showed a synergism in morphological transformation of mammalian cells treated with asbestos and B(a)P. It has been shown that asbestos can mediate lipid peroxidation and that iron cations might be involved in the catalytic activity of asbestos fibers. A previous study of B(a)P metabolism by microsomes showed that peroxidative conditions change the balance between activation and deactivation of B(a)P and demonstrated that catalytically active iron can play a role in this process. The present investigation examines the effect of asbestos on oxidation of B(a)P by superoxide - peroxidized microsomes in vitro

  4. Radiation effects on membranes. I. Vitamin E deficiency and lipid peroxidation

    International Nuclear Information System (INIS)

    Mice which had received a vitamin E-deficient diet from weaning on, were more sensitive to x irradiation than were normal mice, LD/sub 50/30/ being decreased by 0.25 Gy. The vitamin E-deficient mice also showed an increased spleen shrinkage. The cellular membranes of the vitamin E-deficient mice were more vulnerable to lipid peroxidation. X irradiation in vivo shortened the lag period prior to rapid lipid peroxidation as measured in vitro. Injection of the mice with glutathione prior to x irradiation protected the membranes in the in vitro test of peroxidation capacity as was demonstrated by an extended lag period. The possible meaning of these results with respect to the concept that membranes may be important sites for radiation damage is discussed

  5. Radiation effects on membranes. I. Vitamin E deficiency and lipid peroxidation

    Energy Technology Data Exchange (ETDEWEB)

    Konings, A.W.T.; Drijver, E.B.

    1979-12-01

    Mice which had received a vitamin E-deficient diet from weaning on, were more sensitive to x irradiation than were normal mice, LD/sub 50/30/ being decreased by 0.25 Gy. The vitamin E-deficient mice also showed an increased spleen shrinkage. The cellular membranes of the vitamin E-deficient mice were more vulnerable to lipid peroxidation. X irradiation in vivo shortened the lag period prior to rapid lipid peroxidation as measured in vitro. Injection of the mice with glutathione prior to x irradiation protected the membranes in the in vitro test of peroxidation capacity as was demonstrated by an extended lag period. The possible meaning of these results with respect to the concept that membranes may be important sites for radiation damage is discussed.

  6. Chemiluminescence assay for catechin based on generation of hydrogen peroxide in basic solution

    International Nuclear Information System (INIS)

    We have determined that the catechin group in basic solution efficiently produces hydrogen peroxide; moreover, a highly sensitive analysis methodology was developed to measure catechin employing a peroxalate chemiluminescence detection system. Identification of hydrogen peroxide generated by catechin was determined by ESR as well as peroxalate chemiluminescence using catalase and SOD. As a result, catechin-generated superoxide by electron reduction to dissolved oxygen in basic solution, followed by production of hydrogen peroxide through dismutation reaction. This method could measure several tea catechins, (+)-catechin (CC), (-)-epigallocatechin-3-gallate (EGCg), (-)-epicatechin-3-gallate (ECG) and gallic acid, with measurement range from 10-7 to 10-3 mol/l and sensitivity of 10-8 mol/l. This method was also applied to the determination of total catechin levels in green tea, black tea and roasted green tea

  7. Wind-eroded silicate as a source of hydrogen peroxide on Mars

    DEFF Research Database (Denmark)

    Bak, Ebbe Norskov; Merrison, Jonathan P.; Jensen, Svend Knak;

    Introduction: Investigations of Mars as a potential habitat for past or present life depend on understand-ing the chemistry of the Martian soil as it affects the preservation of organic compounds and thus the risk of forward contamination as well as the suitability of organic compounds as...... soil. Methods: We simulated wind-erosion of silicates by tumbling quartz sand in sealed quartz ampoules with defined atmospheres. The eroded sand was suspended in water and the hydrogen peroxide concentration was followed using a sco-poletin/horseradish peroxidase assay. Results: The simulated wind......-erosion effectively eroded the sand over weeks of tumbling and we saw a clear correlation between an increase in surface area and the release of hydrogen peroxide. The production of hydrogen peroxide depended on the presence of atmospheric oxygen and was inhibited by atmospheric carbon dioxide. Nevertheless, taking...

  8. Clinical presentation, lipid peroxidation intensity, and features of nitric oxide production in patients with erysipelas

    Directory of Open Access Journals (Sweden)

    L. I. Ratnikova

    2014-09-01

    Full Text Available 65 patients with a diagnosis of erysipelas. Examination of the patients included an analysis of lipid peroxidation products (common polyene, diene conjugates, and conjugate ketodieny trieny, Schiff bases, antioxidant defense system (enzymatic activity of superoxide dismutase and nitric oxide metabolites (nitrates and nitrites. It was established that imbalance between excess activated lipid peroxidation and inadequate functioning of antioxidant defense system was remained during the entire period of the disease. The relationships between nitric oxide and lipid peroxidation were established. It was proved the advisability of developing and introducing new, improved schemes of pathogenetic therapy of erysipelas.

  9. Study of chromatographic enantioseparation of the esters of N-dinitrobenzoyl (N-DNB) and N-benzoyl (N-B) alpha-amino acids on novel chiral stationary phases containing structurally matching N-DNB and N-B-alpha-AA amides in the chiral selector

    OpenAIRE

    Zafirova, Biljana; Landek, Goran; Kontrec, Darko; Šunjić, Vitomir; Vinković, Vladimir

    2004-01-01

    Enantioseparation ability and enantiopreference of chiral stationary phases CSP 1–CSP 3, containing a terminal N-3,5-dinitrobenzoyl (N-DNB) unit, and CSP 4, containing a terminal N-benzoyl (N-B) unit, are studied. Separation factors (α) for the two sets of test racemates (TR) that structurally match the chiral selector of these CSPs have been determined. The first set consists of seven N-DNB α-amino acid isopropylesters (TR 1A–TR 7A), and the second one of their N-B analogues (TR ...

  10. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    International Nuclear Information System (INIS)

    Highlights: ► Ion beam bombarded rice seeds in vacuum. ► Studied seed survival from the ion bombardment. ► Determined various antioxidant enzyme activities and lipid peroxidation level. ► Discussed vacuum, ion species and ion energy effects. ► Attributed the changes to free radical formation due to ion bombardment. -- Abstract: 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

  11. Synthesis and Photoirradiation of Isomeric Ethylchrysenes by UVA Light Leading to Lipid Peroxidation

    Directory of Open Access Journals (Sweden)

    Peter P. Fu

    2007-06-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are widespread genotoxic environmental pollutants. We have recently demonstrated that photoirradiation of PAHs leads to cytotoxicity, DNA damage, and induction of lipid peroxidation. In this paper we report the synthesis of all the six isomeric ethylchrysenes and the study of light-induced lipid peroxidation by these ethylchrysenes. 5-Ethylchrysene was synthesized by reaction of 5-keto-5,6,6a,7,8,9,10,10a-octahydrochrysene with CH3CH2MgBr followed by dehydration catalyzed by p-toluenesulfonic acid and dehydrogenation with DDQ in benzene. 1- and 4-Ethylchrysenes were similarly prepared by reaction of 1-keto-1,2,3,4,5,6-hexahydrochrysene and 4-keto-1,2,3,4-tetrahydrochrysenes, respectively with CH3CH2MgBr followed by dehydration and dehydrogenation. Direct acetylation of chrysene followed by Wolff-Kishner or Clemmensen reduction resulted in the formation of 2-, 3-, and 6-ethylchrysenes in 4%, 16%, and 43% yields, respectively. Photoirradiation of these compounds with 7 and 21 J/cm2 UVA light in the presence of methyl linoleate all resulted in lipid peroxidation. For comparison, photoirradiation of 4-methylchrysene and 5-methylchrysene was similarly conducted. For irradiation at a UVA light dose of 21 J/cm2, the level of induced lipid peroxidation is in the order 4-methylchrysene = 5-methylchrysene = 5-ethylchrysene = 4-ethylchrysene = chrysene > 1-ethylchrysene = 2-ethylchrysene > 3-ethylchrysene > 6-ethylchrysene. Compared with chrysene, these results indicate that the ethyl group at C4 or C5 position either slightly enhances or has no effect on the light-induced lipid peroxidation, while at C1-, C2-, C3-, or C6 position reduces light-induced lipid peroxidation.

  12. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Energy Technology Data Exchange (ETDEWEB)

    Semsang, Nuananong, E-mail: nsemsang@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, LiangDeng [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► Ion beam bombarded rice seeds in vacuum. ► Studied seed survival from the ion bombardment. ► Determined various antioxidant enzyme activities and lipid peroxidation level. ► Discussed vacuum, ion species and ion energy effects. ► Attributed the changes to free radical formation due to ion bombardment. -- Abstract: 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 × 10{sup 16} ions cm{sup −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.

  13. Effect of Surface Polishing on Mercury Release from Dental Amalgam After Treatment 16% Carbamide Peroxide Gel

    Directory of Open Access Journals (Sweden)

    Z. Khamverdi

    2011-03-01

    Full Text Available Objectives: This study evaluated the effect of surface polishing on mercury release from dental amalgam after treatment with 16% carbamide peroxide gel.Materials and Methods: Ninety-six samples from two different amalgam brands were prepared in truncated cone-shaped PVC polymer molds with an external surface area of 195 mm². Half of the specimens were polished with green and red rubber, a brush and tin oxide paste at low speed. Samples were treated with 16% carbamide peroxide gel intubes containing 3 mL of carbamide peroxide gel and 0.1 mL of distilled water for 14 and 28 hours. Subsequently, carbamide peroxide gel on the sample surfaces was rinsed away with 7.0 mL of distilled water until the volume of each tube increased to 10 mL. Themercury level of each solution was measured using the VAV–440 mercury analyzer system.Considering the surface area of each amalgam disc, mercury amounts were calculated in μg ⁄mm². Data were analyzed using two-way ANOVA.Results: There were significant differences between the mean levels of mercury release from polished vs. unpolished amalgam surfaces after treatment with 16% carbamide peroxide.Increasing the storage time from 14 to 28 hours did not result in significant changes in the amount of mercury release. There was no significant interaction effect between amalgam surface polish and storage time statistically.Conclusion: Polished amalgam restorations release less mercury after treatment with carbamide peroxide bleaching gel in comparison with unpolished amalgam restorations.

  14. Influence of ph on corrosion control of carbon steel by peroxide injection in sour water

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Martins Magda; Baptista, Walmar; Joia, Carlos Jose Bandeira de Mello [PROTEMP - PETROBRAS/CENPES, Cidade Universitaria, Quadra 7, Rio de Janeiro, CEP 21949-900 (Brazil); Ponciano, Gomes Jose Antonio da Cunha [Departamento de Engenharia Metalurgica e de Materiais-COPPE/UFRJ, Cidade Universitaria, Rio de Janeiro (Brazil)

    2004-07-01

    Sour hydrogen damage is considered the most important corrosive process in the light-ends recovery section of Fluid Catalytic Cracking Units (FCCU). Corrosion in this condition is due to heavy gas oil that originates great amount of contaminants, such as H{sub 2}S, NH{sub 3} and HCN. Hydrogen absorption is promoted by the presence of free cyanides in the environment. The attenuation of this process requires the use of some inhibitors, such as oxygen, hydrogen peroxide (H{sub 2}O{sub 2}) or commercial polysulfides. The effect of these compounds is to neutralize free cyanides (CN{sup -}) into thio-sulfides (SCN{sup -}). When peroxide injection is selected, cyanide concentration in sour water has been used as key parameter to start the peroxide introduction. However, the importance of pH in this system has been pointed out by many authors. The aim of this work is to investigate the influence of pH when peroxide injection is carried out in less alkaline conditions of sour water. Electrochemical techniques - like anodic polarization and hydrogen permeation tests - and weight loss measurements were used to evaluate the effectiveness of corrosion control of carbon steel. It was concluded that at pH 7.5 peroxide injection can drive to an increment of the corrosion rate. Besides that, it was concluded that hydrogen permeation into the metal is promoted. Both detrimental effects were due to elemental sulfur generation in this pH range. The adoption of pH as a key parameter for peroxide injection is then suggested. (authors)

  15. Kinetics of wet peroxide oxidation of phenol with a gold/activated carbon catalyst

    OpenAIRE

    Domínguez, Carmen M.; Quintanilla, Asunción; Casas, José Antonio; Rodríguez, Juan José

    2014-01-01

    Gold nanoparticles supported on activated carbon (Au/AC) have been tested in catalytic wet peroxide oxidation using phenol as target pollutant. In the current work, the effect of several operating conditions, including initial pH (3.5–10.5), catalyst load (0–6 g/L), initial phenol concentration (0.1–5 g/L), hydrogen peroxide dose (4–100% of the theoretical stoichiometric amount) and reaction temperature (50–80 °C) has been investigated. The results show that the Au/AC catalyst would be useful...

  16. Progress in alkaline peroxide dissolution of low-enriched uranium metal and silicide targets

    International Nuclear Information System (INIS)

    This paper reports recent progress on two alkaline peroxide dissolution processes: the dissolution of low-enriched uranium metal and silicide (U3Si2) targets. These processes are being developed to substitute low-enriched for high-enriched uranium in targets used for production of fission-product 9'9Mo. Issues that are addressed include (1) dissolution kinetics of silicide targets, (2) 99Mo lost during aluminum dissolution, (3) modeling of hydrogen peroxide consumption, (4) optimization of the uranium foil dissolution process, and (5) selection of uranium foil barrier materials. Future work associated with these two processes is also briefly discussed. (author)

  17. Solvent extraction of tungsten with tri-n-octylamine from hydrogen peroxide solutions

    International Nuclear Information System (INIS)

    Conditions for fast metallic tungsten dissolution in hydrogen peroxide solutions are found and regularities of its extraction by tri-n-octylamine in the form of peroxide compounds and isopolytungstates from hydrochloric, sulfuric acid nitric acid solutions are studied. W and TOA ratio in the formed organic complex is determined by studying extraction isotherms using equilibrium shift, saturation, isomolar series, IR spectrometry methods and this complex'es composition is assumed. Radiochemical circuit of extraction-chromatographic separation of tungsten and rhenium is developed and a method for fast isolation of rhenium-183, 184 radio nuclides from metallic tungsten, irradiated with charged particles is proposed

  18. Four-step synthesis of the antimalarial cardamom peroxide via an oxygen stitching strategy.

    Science.gov (United States)

    Hu, Xirui; Maimone, Thomas J

    2014-04-01

    A four-step synthesis of the antimalarial terpene cardamom peroxide, a 1,2-dioxepane-containing natural product, is reported from (-)-myrtenal and molecular oxygen. This highly concise route was guided by biosynthetic logic and enabled by an unusual manganese-catalyzed, tandem hydroperoxidation reaction. The absolute configuration of the cardamom peroxide is reported, and its mode of fragmentation following Fe(II)-mediated endoperoxide reduction is established. These studies reveal the generation of reactive intermediates distinct from previously studied endoperoxide natural products. PMID:24673099

  19. The Erosion Properties of Chlorine Dioxide and Hydrogen Peroxide on Bovine Teeth

    OpenAIRE

    Ablal MA; Jarad FD; Adeyemi AA

    2015-01-01

    Objectives: The aim of this study was to assess the erosion potential of chlorine dioxide and hydrogen peroxide on bovine teeth. Methods: Sixty bovine crowns were ground and polished to give flat surfaces. The crowns were subjected to heavy staining cycles then equally divided into 3 treatment groups; chlorine dioxide (ClO2), hydrogen peroxide (H2O2), and deionised water (H2O). Specimens in each group were immersed in 150 ml of the treatment for seven 2 min cycle in addition...

  20. Lipid peroxidation in rat blood following a single administration of different active 131I

    International Nuclear Information System (INIS)

    Peroxidation in rat blood male Wistar by chemiluminescence single ingestion of radioactive iodine was investigated. Introduction of activity (3.3, 19.2 and 90 kBq per animal) cause changes in the indices of the chemiluminescent reaction (sum light emission, the final intensity of the glow, the time to reach maximum values), the value of which is not significantly dependent on the administration of the active isotope was shown. There were no significant changes in catalase activity in the blood. The features of the flow processes of peroxide in the blood of rats with single administration 131I were discussed