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Sample records for benzoyl peroxide

  1. Clindamycin and Benzoyl Peroxide Topical

    Science.gov (United States)

    ... benzoyl peroxide works by killing the bacteria that cause acne. ... E-Mycin, Erythrocin) and other topical medications for acne. Your doctor ... colitis (a condition which causes swelling and sores in the lining of the ...

  2. Formulation and characterization of benzoyl peroxide gellified emulsions.

    Science.gov (United States)

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

    2012-12-01

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

  3. 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

  4. 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...

  5. 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.

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

    Science.gov (United States)

    Chu, Lingling; Qing, Feng-Ling

    2010-09-14

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

  7. 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

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

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

  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 25...

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

    Science.gov (United States)

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

    2011-09-01

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

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

    Science.gov (United States)

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

    2011-09-01

    The clinical and antibacterial efficacy of two shampoos used as a sole antibacterial treatment in dogs with superficial pyoderma were investigated and compared. In a randomised, partially blinded study, a 3 per cent chlorhexidine gluconate shampoo (Chlorhex 3; Leo Animal Health) was compared against a 2.5 per cent benzoyl peroxide shampoo (Paxcutol; Virbac) in 22 dogs with superficial pyoderma. Dogs were washed two to three times weekly with a 10-minute contact time over 21 days. Clinical scores and bacterial counts were assessed on days 1, 8 and 22 and compared within and between treatment groups; overall response was assessed at the end of the study. Twenty dogs completed the study; 15 (68.2 per cent) showed an overall clinical improvement and the clinical signs resolved in three chlorhexidine-treated dogs. In the chlorhexidine-treated group, scores for papules/pustules (P<0.001), investigator-assessed pruritus (P=0.003), total bacterial counts (P=0.003) and counts for coagulase-positive staphylococci (P=0.003) were reduced after three weeks. Scores and bacterial counts did not vary significantly in the benzoyl peroxide-treated group. PMID:21831997

  17. 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.

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

    Science.gov (United States)

    Maldonado, Frank; Stashans, Arvids

    2016-04-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    Topical benzoyl peroxide (BPO) gel has long been used to treat acne vulgaris and has recently been combined with clindamycin (BPO-clin). No skin malignancies have been reported after clinical use of BPO, but there has been concern about the possible carcinogenicity of BPO alone and in combination...... with UV radiation. BPO can promote skin tumorigenesis in a mouse skin chemical carcinogenesis model. As acne vulgaris is frequently localized on sun-exposed areas, we investigated whether BPO or BPO-clin accelerates photocarcinogenesis in combination with simulated solar radiation (SSR) in 12 groups of 25...... hairless female C3.Cg/TifBomTac-immunocompetent mice. BPO or BPO-clin was applied topically to the back five times each week, followed by SSR three times each week (2, 3, or 4 standard erythema doses) 3-4 h later, for 365 days or until death. Generally BPO and BPO-clin did not accelerate the time to first...

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

    Science.gov (United States)

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

    1991-06-01

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

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

    Science.gov (United States)

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

    1991-06-01

    Fish or vegetable oils were fed during the promotion stage of a mouse skin carcinogenesis model in order to investigate the effects of dietary fat on tumor development. Two weeks after initiation with 10 nmol dimethylbenz[a]anthracene, SENCAR mice were divided into five groups and maintained on one of the following semipurified diets containing 10% total fat and varying the type of fat: 8.5% coconut oil (CT)/1.5% corn oil (CO); 1% menhaden oil (MO)/7.5% CT/1.5% CO; 4% MO/4.5% CT/1.5% CO; 8.5% MO/1.5% CO; or 10% CO. Promotion with twice-weekly applications of 40 mg benzoyl peroxide was begun 2 weeks later and continued for 52 weeks. No statistically significant differences in kcal food consumed or body weights were observed between diet groups. Papilloma latency, incidence and yield differed among the diet groups with the group fed the 8.5% CT/1.5% CO diet having the shortest latency and highest papilloma incidence and number. In addition, carcinoma latency and incidence was assessed and the first carcinoma appeared in the group fed 8.5% CT/1.5% CO after 20 weeks of benzoyl peroxide treatment; this group yielded the highest carcinoma incidence throughout the study. In comparison, the group fed the 10% CO diet had the longest latency period, and among the lowest papilloma and carcinoma incidence and fewest tumors. In parallel studies, ornithine decarboxylase activity, vascular permeability and hyperplasia were elevated in the epidermis of benzoyl peroxide-treated mice but the extent of the response did not correlate with the different rates of tumor formation observed among the diet groups. These data indicate that dietary fat modulates tumor promotion by benzoyl peroxide in this skin carcinogenesis model with the predominantly saturated fat diet producing the highest rates of papilloma and carcinogen formation and the polyunsaturated fat diet the lowest. PMID:1904320

  2. 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.

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

    Science.gov (United States)

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

    2014-03-01

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

  4. 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

  5. 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.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2011-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Kraingkrai Ponhong

    2015-12-01

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

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

    Science.gov (United States)

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

    2012-05-01

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

  10. 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.

  11. 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.

  12. 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.

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

    Science.gov (United States)

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

    2015-11-01

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

  14. 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.

  15. 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...

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

    OpenAIRE

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

    2013-01-01

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

  17. 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

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

    Science.gov (United States)

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

    2016-06-01

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

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

    Science.gov (United States)

    Babaeinejad, S H; Fouladi, R F

    2013-09-01

    Topical treatments, such as adapalene and benzoyl peroxide (BPO), are popular in mild-to-moderate acne vulgaris. This study aimed to compare the efficacy, safety and tolerability of adapalene and BPO in mild acne vulgaris. In this single-center, randomized, double-blind, clinical trial, 60 patients with mild acne vulgaris received either topical adapalene 0.1% gel or topical BPO 2.5% gel on their face once daily for two months. The changes of acne lesion count (efficacy), any adverse effect (safety), and the patients' overall satisfaction (tolerability) were compared after 3 months of follow-up. In both groups the mean number of noninflammatory, inflammatory and total lesions decreased significantly from baseline (10.77±5.54, 9.73±5.09, and 20.50±7.54, respectively in adapalene group; 11.50±5.92, 8.43±5.45, and 19.93±9.01, respectively in BPO group) to the third month (1.70±1.68, 0.33±0.66, and 0.50±0.78, respectively in adapalene group; 4.23±4.14, 0.33±0.71, and 4.13±4.44, respectively in BPO group; PBPO receivers only at first month (P=0.001), the mean number of noninflammatory and total lesions was significantly lower in adapalene group at second (P= 0.04 and 0.03, respectively) and third (P=0.02 and BPO group, P=0.54). The patients' overall satisfaction was good-excellent in 93.3% of adapalene receivers vs. 73.3% in BPO group (P=0.08). Both topical adapalene 0.1% and BPO 2.5% gels seem safe and effective in mild acne vulgaris, with a marginal tendency toward the former.

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

    Science.gov (United States)

    Babaeinejad, S H; Fouladi, R F

    2013-07-01

    Topical treatments, such as adapalene and benzoyl peroxide (BPO), are popular in mild-to-moderate acne vulgaris. This study aimed to compare the efficacy, safety and tolerability of adapalene and BPO in mild acne vulgaris. In this single-center, randomized, double-blind, clinical trial, 60 patients with mild acne vulgaris received either topical adapalene 0.1% gel or topical BPO 2.5% gel on their face once daily for two months. The changes of acne lesion count (efficacy), any adverse effect (safety), and the patients' overall satisfaction (tolerability) were compared after 3 months of follow-up. In both groups the mean number of noninflammatory, inflammatory and total lesions decreased significantly from baseline (10.77±5.54, 9.73±5.09, and 20.50±7.54, respectively in adapalene group; 11.50±5.92, 8.43±5.45, and 19.93±9.01, respectively in BPO group) to the third month (1.70±1.68, 0.33±0.66, and 0.50±0.78, respectively in adapalene group; 4.23±4.14, 0.33±0.71, and 4.13±4.44, respectively in BPO group; PBPO receivers only at first month (P =0.001), the mean number of noninflammatory and total lesions was significantly lower in adapalene group at second (P = 0.04 and 0.03, respectively) and third (P =0.02 and BPO group, p=0.54). The patients' overall satisfaction was good to excellent in 93.3% of adapalene receivers vs. 73.3% in BPO group (P=0.08). Both topical adapalene 0.1% and BPO 2.5% gels seem safe and effective in mild acne vulgaris, with a marginal tendency toward the former.

  1. STUDY ON BENZOYL PEROXIDE RAPID TEST STRIP%过氧化苯甲酰快速检测试纸的研究

    Institute of Scientific and Technical Information of China (English)

    谢岩黎; 李雪琴; 何保山; 王芬; 杨杰; 魏嘉

    2011-01-01

    Benzoyl peroxide has strong oxidation ability, and can react with potassium iodide to generate benzoic acid and iodine. Therefore, the rapid test strip can be prepared according to the principle of the color reaction of starch and iodide. A cellulose acetate membrane was used as the color layer, then was soaked in a color reagent mixture solution containing 0.4% gelatinized starch solution, 10% KI and 4% Na2CO3 for 5 minutes, and was dried under vacuum to obtain the test strip. A standard colourimetric card consisted often color blocks, and could show significant color order in the range of benzoyl peroxide 0 to 228 mg/L. The lowest detection limit of benzoyl peroxide in the flour was 36 mg/kg, and the relative error was 11.76% to 16.89%.%过氧化苯甲酰具有强氧化性,与碘化钾反应生成苯甲酸和碘,根据碘与淀粉反应呈蓝色的原理研究制作快速检测试纸.将醋酸纤维素膜作为显色层,浸入由0.4%的糊化淀粉溶液、10%KI和4%的Na2CO3组成的混合显色剂,浸泡5 min后,真空干燥制备出检测试纸;标准比色卡由10个色块组成,过氧化苯甲酰质量浓度在0~228 mg/L范围内色阶明显,对面粉中过氧化苯甲酰最低检出限为36 mg/kg,相对误差范围为11.76%~16.89%.

  2. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  4. 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

  5. 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.

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

    Science.gov (United States)

    Leyden, James

    2016-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  8. 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

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

    Science.gov (United States)

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

    2013-03-01

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

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

    Institute of Scientific and Technical Information of China (English)

    梁新亮; 张守民

    2011-01-01

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

  11. 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.

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

    Institute of Scientific and Technical Information of China (English)

    苏磊; 吴学华; 刘秀茹; 陈丽英; 陈克宇; 洪时明

    2005-01-01

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

  13. 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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2014-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Kabir Sardana

    2016-01-01

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

  17. Inner-shell excitation spectroscopy of peroxides

    NARCIS (Netherlands)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2014-06-20

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

  19. 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

  20. 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

  1. 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.

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

    DEFF Research Database (Denmark)

    Hazlewood, C; Davies, Michael Jonathan

    1996-01-01

    , sugars, nucleosides, nucleotides, RNA, and DNA have been examined and the intermediate species have been identified in many cases. Comparison of these data with those obtained with Ph. alone has allowed the reactions of PhCO2. and Ph. to be distinguished. Evidence has been obtained which is consistent...... of base adducts, though the exact identity of the species detected in these cases could not be determined due to the complexity of the spectra. Hydrogen abstraction at the sugar-phosphate backbone is also believed to occur with these substrates as strand breakage is observed; the extent of the latter...... is dependent on the radical flux and the attacking species, with PhCO2. appearing to be a much more effective inducer of fragmentation than Ph. The nature of the species detected with all the substrates examined, with the exception of the isolated sugars where essentially random attack by both radicals...

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

    Science.gov (United States)

    Epstein, J H

    1988-08-01

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

  4. 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...

  5. 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.

  6. 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...

  7. Improved Convenient Synthesis of Benzoyl Metronidazole: A Nitroimidazole Antibiotics

    Directory of Open Access Journals (Sweden)

    Zhi-zhong Wang

    2013-01-01

    Full Text Available An improved, cost-effective, and one-pot method for the synthesis of benzoyl metronidazole was achieved by using N,N′-carbonyldiimidazole as a coupling reagent. Moreover, the byproduct imidazole as the catalyst promoted the reaction. The procedures are simple and suitable to large-scale manufactures.

  8. Antimalarial peroxides

    Directory of Open Access Journals (Sweden)

    DEJAN M. OPSENICA

    2009-11-01

    Full Text Available The problem of endemic malaria continues unabated globally. Malaria affects 40 % of the global population, causing an estimated annual mortality of 1.5–2.7 million people. The World Health Organization (WHO estimates that 90 % of these deaths occur in sub-Saharan Africa among infants under the age of five. While a vaccine against malaria continues to be elusive, chemotherapy remains the most viable alternative towards treatment of the disease. During last years, the situation has become urgent in many ways, but mainly because of the development of chloroquine-resistant (CQR strains of Plasmodium falciparum (Pf. The discovery that artemisinin (ART, 1, an active principle of Artemisia annua L., expresses a significant antimalarial activity, especially against CQR strains, opened new approaches for combating malaria. Since the early 1980s, hundreds of semisynthetic and synthetic peroxides have been developed and tested for their antimalarial activity, the results of which were extensively reviewed. In addition, in therapeutic practice, there is no reported case of drug resistance to these antimalarial peroxides. This review summarizes recent achievements in the area of peroxide drug development for malaria chemotherapy.

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

    Science.gov (United States)

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

    2014-06-01

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

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Yuchao Lu

    2016-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Aymerick Eudes

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  15. 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

  16. 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)

  17. 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)

  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

    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 ...

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

    Directory of Open Access Journals (Sweden)

    José R. Pedro

    2004-04-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

  2. 75 FR 9767 - Classification of Benzoyl Peroxide as Safe and Effective and Revision of Labeling to Drug Facts...

    Science.gov (United States)

    2010-03-04

    ..., resorcinol monoacetate, salicylic acid and/or sulfur to meet OTC drug labeling content and format... resorcinol, resorcinol monoacetate, salicylic acid, and/or sulfur subject to 21 CFR part 333 is March 4, 2015..., resorcinol, resorcinol monoacetate, salicylic acid, and/or sulfur be relabeled. We revised the warnings...

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  4. 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

  5. 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

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

    Institute of Scientific and Technical Information of China (English)

    闫涛; 于淑晶; 刘鹏飞; 刘卓; 王宝雷; 熊丽霞; 李正名

    2012-01-01

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

  7. 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...

  8. 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...

  9. 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.

  10. 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)

  11. 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.

  12. 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

  13. 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).

  14. 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)

  15. 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)

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

    Science.gov (United States)

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

    2016-01-01

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

  17. 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

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-15

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

  20. 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

  1. 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.

  2. ADSORPTION OF 4-METHYLANILINE IN AQUEOUS SOLUTION BY BENZOYL- CONTAINING POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    Gen-cheng Zhang; Hai-suo Wu; Zheng-hao Fei

    2005-01-01

    New polymeric adsorbents (ZH-02, ZH-03) containing benzoyl group for adsorbing and removing 4-methylaniline from its aqueous solutions were prepared. Studies on the isotherms and the comparison of desorption conditions evidenced through the adsorption of 4-methylaniline in water onto ZH-02 and ZH-03, namely that there are chemisorption's transitions at a proper higher temperature. Mini-column adsorption studies of 4-methylaniline on XAD-4, ZH-02 and ZH-03 at 288 K show that the breakthrough capacities are 2.39, 2.99 and 3.19 mmol/g and the total capacities are 3.45, 3.92 and 4.35 mmol/g, respectively.

  3. 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...

  4. 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.

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

    Science.gov (United States)

    Reinhard, K; Matern, U

    1989-11-15

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

  6. 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

  7. 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

  8. 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,...

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

    Institute of Scientific and Technical Information of China (English)

    刘泽华; 王守兴; 段春迎; 游效曾

    2001-01-01

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

  10. 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

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

    Institute of Scientific and Technical Information of China (English)

    刘荣琴; 高磊红; 李荣芬

    2013-01-01

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

  12. 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...

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    Podunavac-Kuzmanović Sanja O.

    2002-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2002-01-01

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

  16. 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)

  17. 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.

  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. 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

  20. 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)

  1. 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)

  2. 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.

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

    Science.gov (United States)

    Bilotta, J J; Waye, J D

    1989-01-01

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

  4. Hydrogen peroxide is a true first messenger.

    Science.gov (United States)

    Holmquist, L; Stuchbury, G; Steele, M; Münch, G

    2007-01-01

    Hydrogen peroxide has been shown to act as a second messenger mediating intracellular redox-sensitive signal transduction. Here we show that hydrogen peroxide is also able to transmit pro-inflammatory signals from one cell to the other and that this action can be inhibited by extracellularly added catalase. If these data can be further substantiated, hydrogen peroxide might become as important as nitric oxide as a small molecule intercellular (first) messenger.

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  6. PEROXIDE BLEACHING OF LOW-FREENESS TMP

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2002-01-01

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

  8. 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.

  9. 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)-.

  10. 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...

  11. 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...

  12. 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...

  13. 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

  14. Rearrangements of organic peroxides and related processes

    Science.gov (United States)

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

    2016-01-01

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

  15. 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

  16. 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…

  17. MEASUREMENT AND MODELING OF THE DRY DEPOSITION OF PEROXIDES

    Science.gov (United States)

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

  18. Detection of hydrogen peroxide with chemiluminescent micelles

    Directory of Open Access Journals (Sweden)

    Dongwon Lee

    2008-08-01

    Full Text Available Dongwon Lee1, Venkata R Erigala1,3, Madhuri Dasari1, Junhua Yu2, Robert M Dickson2, Niren Murthy11The Wallace H. Coulter Department of Biomedical Engineering; 2Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA; 3The Scripps Research Institute, La Jolla, CA, USAAbstract: The overproduction of hydrogen peroxide is implicated in the progress of numerous life-threatening diseases and there is a great need for the development of contrast agents that can detect hydrogen peroxide in vivo. In this communication, we present a new contrast agent for hydrogen peroxide, termed peroxalate micelles, which detect hydrogen peroxide through chemiluminescence, and have the physical/chemical properties needed for in vivo imaging applications. The peroxalate micelles are composed of amphiphilic peroxalate based copolymers and the fluorescent dye rubrene, they have a ‘stealth’ polyethylene glycol (PEG corona to evade macrophage phagocytosis, and a diameter of 33 nm to enhance extravasation into permeable tissues. The peroxalate micelles can detect nanomolar concentrations of hydrogen peroxide (>50 nM and thus have the sensitivity needed to detect physiological concentrations of hydrogen peroxide. We anticipate numerous applications of the peroxalate micelles for in vivo imaging of hydrogen peroxide, given their high sensitivity, small size, and biocompatible PEG corona.Keywords: hydrogen peroixde, chemiluminescence, micelles, amphiphilic copolymer

  19. 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

  20. Membrane transport of hydrogen peroxide.

    Science.gov (United States)

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

    2006-08-01

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

  1. Detection of interstellar hydrogen peroxide

    CERN Document Server

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

    2011-01-01

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

  2. 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.

  3. Lipid peroxidation in experimental uveitis: sequential studies.

    Science.gov (United States)

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

    1992-06-01

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

  4. 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)

  5. 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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-11-01

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

  8. 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.

  9. EFFLUENT TREATMENT FACILITY PEROXIDE DESTRUCTION CATALYST TESTING

    Energy Technology Data Exchange (ETDEWEB)

    HALGREN DL

    2008-07-30

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-06-01

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

  11. 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...

  12. 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...

  13. 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.

  14. 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

  15. [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

  16. 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.

  17. Electronic structure and bonding in crystalline peroxides

    Science.gov (United States)

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

    1999-08-01

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

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

    Institute of Scientific and Technical Information of China (English)

    李水清; 赵春

    2011-01-01

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

  19. 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.

  20. 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...

  1. 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.

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

    Science.gov (United States)

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

    2016-01-01

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

  3. 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.

  4. 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.

  5. 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.

  6. 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)

  7. 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.

  8. 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

  9. 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...

  10. 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...

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

    Directory of Open Access Journals (Sweden)

    Mohammed Mahbubul Matin

    2016-08-01

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

  12. 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)

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

    Science.gov (United States)

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

    2016-01-01

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

  14. 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.

  15. 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)

  16. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

  18. 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.

  19. 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...

  20. 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...

  1. 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)

  2. 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.

  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. 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...

  6. 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.

  7. 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.

  8. 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

  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. 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...

  12. 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

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

    NARCIS (Netherlands)

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

    1995-01-01

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

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

    NARCIS (Netherlands)

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

    1995-01-01

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

  15. 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

  16. 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

  17. Demonstration of the Catalytic Decomposition of Hydrogen Peroxide.

    Science.gov (United States)

    Conklin, Alfred R. Jr.; Kessinger, Angela

    1996-01-01

    Describes a demonstration known as Elephant's Toothpaste in which the decomposition of hydrogen peroxide is catalyzed by iodide. Oxygen is released and soap bubbles are produced. The foam produced is measured, and results show a good relationship between the amount of foam and the concentration of the hydrogen peroxide. (DDR)

  18. A hydrogen peroxide sensor for exhaled breath measurement

    NARCIS (Netherlands)

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

    2005-01-01

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

  19. A hydrogen peroxide sensor for exhaled breath measurement

    NARCIS (Netherlands)

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

    2004-01-01

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

  20. 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

  1. 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.

  2. Locating bomb factories by detecting hydrogen peroxide.

    Science.gov (United States)

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

    2016-11-01

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

  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. 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

  5. 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+ .

  6. 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.

  7. 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.

  8. 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.

  9. 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

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

    Directory of Open Access Journals (Sweden)

    Alexander O. Terent'ev

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  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. 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.

  14. 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.

  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

    2015-09-01

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

  16. Stable magnesium peroxide at high pressure

    Science.gov (United States)

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

    2015-09-01

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

  17. 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

  18. 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...

  19. Benzoyl-coenzyme A reductase (dearomatizing), a key enzyme of anaerobic aromatic metabolism. ATP dependence of the reaction, purification and some properties of the enzyme from Thauera aromatica strain K172.

    Science.gov (United States)

    Boll, M; Fuchs, G

    1995-12-15

    Anoxic metabolism of many aromatic compounds proceeds via the common intermediate benzoyl-CoA. Benzoyl-CoA is dearomatized by benzoyl-CoA reductase (dearomatizing) in a two-electron reduction step, possibly yielding cyclohex-1,5-diene-1-carboxyl-CoA. This process has to overcome a high activation energy and is considered a biological Birch reduction. The central, aromatic-ring-reducing enzyme was investigated for the first time in the denitrifying bacterium Thauera aromatica strain K172. A spectrophotometric assay was developed which was strictly dependent on MgATP, both with cell extract and with purified enzyme. The oxygen-sensitive new enzyme was purified 35-fold with 20% yield under anaerobic conditions in the presence of 0.25 mM dithionite. It had a native molecular mass of approximately 170 kDa and consisted of four subunits a,b,c,d of 48, 45, 38 and 32 kDa. The oligomer composition of the protein most likely is abcd. The ultraviolet/visible spectrum of the protein as isolated, but without dithionite, was characteristic for an iron-sulfur protein with an absorption maximum at 279 nm and a broad shoulder at 390 nm. The estimated molar absorption coefficient at 390 nm was 35,000 M-1 cm-1. Reduction of the enzyme by dithionite resulted in a decrease of absorbance at 390 nm, and the colour turned from greenish-brown to red-brown. The enzyme contained 10.8 +/- 1.5 mol Fe and 10.5 +/- 1.5 mol acid-labile sulfur/mol. Besides zinc (0.5 mol/mol protein) no other metals nor selenium could be detected in significant amounts. The enzyme preparation contained a flavin or flavin-like compound; the estimated content was 0.3 mol/mol enzyme. The enzyme reaction required MgATP and a strong reductant such as Ti(III). The reaction catalyzed is: benzoyl-CoA + 2 Ti(III) + n ATP-->non-aromatic acyl-CoA + 2 Ti(IV) + n ADP + n Pi. The estimated number n of ATP molecules hydrolyzed/two electrons transferred in benzoyl-CoA reduction is 2-4. In the absence of benzoyl-CoA the enzyme

  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. 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.

  3. 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

  4. 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...

  5. 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.

  6. 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...

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

    Science.gov (United States)

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

    2012-12-21

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

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

    NARCIS (Netherlands)

    BENAK, H; ENGBERTS, JBFN; BLANDAMER, MJ

    1992-01-01

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

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

    Science.gov (United States)

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

    2013-03-01

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

  10. 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.

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

    Science.gov (United States)

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

    1997-12-01

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

  12. 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

  13. 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

  14. 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

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  17. 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

  18. 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

  19. 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

  20. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  2. The photoprotective effects of 2-benzoyl-3-phenylquinoxaline 1,4-dioxide against UVB-induced damage in HaCaT cells.

    Science.gov (United States)

    Mouawad, Joe; Saadeh, Fadi; Tabosh, Hayat Al; Haddadin, Makhluf J; Gali-Muhtasib, Hala

    2016-08-01

    With the increasing levels of atmospheric ozone depletion, there has been much concern about the causal effects of high levels of ultraviolet radiation reaching the Earth's surface on skin cancer. This has led to growing interest in identifying new active ingredients for use in commercial sunscreens. In our study, the chemical compound 2-benzoyl-3-phenylquinoxaline 1,4-dioxide (BPQ) prepared by the Beirut reaction was tested for its ability to protect a human keratinocyte cell line (HaCaT) against ultraviolet B radiation (280-315 nm). We show that BPQ exhibited strong absorbance in the UVB range, with an overall absorption spectrum very similar to that of Padimate-O, a well-known active ingredient used in commercial sunscreens. HaCaT cells, which were irradiated with UVB in the presence of multiple doses of BPQ, exhibited, in a dose-dependent fashion, a significantly higher viability and lower oxidative stress levels than cells irradiated in the absence of drug. Our results show that BPQ is a potential photoprotective drug that holds great promise for use as an active ingredient in commercial sunscreens. PMID:27377483

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. Chlamydia trachomatis and sperm lipid peroxidation in infertile men

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

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

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. Oxidative desulfurization of Tufanbeyli coal by hydrogen peroxide solution

    Energy Technology Data Exchange (ETDEWEB)

    Guru, M.; Sarioz, B.V.; Cakanyildirim, C. [Gazi University, Ankara (Turkey). Dept. of Chemical Engineering

    2008-07-01

    It is becoming popular to use fossil fuels efficiently since the necessary energy is mostly supplied from fossil fuels. Altough there are high lignite reserves, high sulfur content limits the efficient use of them. In this article, we aimed to convert combustible sulfur in coal to non-combustible sulfate form in the ash by oxidizing it with a hydrogen peroxide solution. The parameters affecting the sulfur conversion were determined to be: hydrogen peroxide concentration, reaction time, mean particle size at constant room temperature and shaking rate. The maximum desulfurization efficiency reached was 74% of the original combustible sulfur with 15% (w/w) hydrogen peroxide solution, 12 hours of reaction time, and 0.25 mm mean particle size.

  13. 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

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

    Science.gov (United States)

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

    1998-01-01

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

  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. 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.

  17. 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.

  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. 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

  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. 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.

  2. 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.

  3. 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

  4. 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

  5. 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...

  6. 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.

  7. 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.

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  9. 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

  10. 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.

  11. Enzymatic generation of hydrogen peroxide shows promising antifouling effect

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  12. 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.

  13. 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...

  14. LIPID PEROXIDATION AND JOB STRESS IN DENTAL HEALTHCARE WORKERS

    Directory of Open Access Journals (Sweden)

    S. V. Melnikova

    2014-04-01

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

  15. 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.

  16. 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.

  17. 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.

  18. 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...

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

    NARCIS (Netherlands)

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

    2005-01-01

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

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

  1. 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...

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. EVALUATION OF ANTIOXIDANTS AND LIPID PEROXIDATION STATUS AMONG STUDENTS

    Directory of Open Access Journals (Sweden)

    Anandh T

    2012-12-01

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

  7. 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.

  8. 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

  9. 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.

  10. 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 ...

  11. 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 ...

  12. 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.

  13. 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.

  14. 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

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

    Science.gov (United States)

    Mehrdad, Abbas; Hashemzadeh, Robab

    2010-01-01

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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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)

  1. 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.

  2. 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.

  3. 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...

  4. 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...

  5. 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.)

  6. [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

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

    Institute of Scientific and Technical Information of China (English)

    陈建成; 张世平

    2012-01-01

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

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

    Science.gov (United States)

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

    2008-09-01

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

  9. 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.

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

    Science.gov (United States)

    Kavana, Michael; Moran, Graham R

    2003-09-01

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

  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. 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.

  13. HYDROGEN PEROXIDE BLEACHING OF CMP PULP USING MAGNESIUM HYDROXIDE

    Directory of Open Access Journals (Sweden)

    Farhad Zeinaly

    2009-11-01

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

  14. 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...

  15. 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 ...

  16. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation

    DEFF Research Database (Denmark)

    Viswanathan, Venkatasubramanian; Hansen, Heine Anton; 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. 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...... 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....

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

    Science.gov (United States)

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

    2009-05-01

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

  18. 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.

  19. 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.

  20. 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.

  1. Overoxidation of chloroplast 2-Cys peroxiredoxins: balancing toxic and signaling activities of hydrogen peroxide

    OpenAIRE

    Puerto-Galán, Leonor; Pérez-Ruiz, Juan M.; Ferrández, Julia; Cano, Beatriz; Naranjo, Belén; Nájera, Victoria A.; González, Maricruz; Lindahl, Anna M.; Cejudo, Francisco J.

    2013-01-01

    Photosynthesis, the primary source of biomass and oxygen into the biosphere, involves the transport of electrons in the presence of oxygen and, therefore, chloroplasts constitute an important source of reactive oxygen species, including hydrogen peroxide. If accumulated at high level, hydrogen peroxide may exert a toxic effect; however, it is as well an important second messenger. In order to balance the toxic and signaling activities of hydrogen peroxide its level has to be tightly controlle...

  2. Boronate-Based Fluorescent Probes: Imaging Hydrogen Peroxide in Living Systems

    OpenAIRE

    Lin, Vivian S.; Dickinson, Bryan C; Chang, Christopher J.

    2013-01-01

    Hydrogen peroxide, a reactive oxygen species with unique chemical properties, is produced endogenously in living systems as a destructive oxidant to ward off pathogens or as a finely tuned second messenger in dynamic cellular signaling pathways. In order to understand the complex roles that hydrogen peroxide can play in biological systems, new tools to monitor hydrogen peroxide in its native settings, with high selectivity and sensitivity, are needed. Knowledge of organic synthetic reactivity...

  3. Overoxidation of chloroplast 2-Cys peroxiredoxins: balancing toxic and signaling activities of hydrogen peroxide

    OpenAIRE

    Leonor ePuerto-Galán; Juan Manuel Pérez-Ruiz; Julia eFerrández; Beatriz eCano; Belén eNaranjo; Victoria Armario Nájera; Maricruz eGonzález; Anna Marika eLindahl; Francisco Javier Cejudo

    2013-01-01

    Photosynthesis, the primary source of biomass and oxygen into the biosphere, involves the transport of electrons in the presence of oxygen and, therefore, chloroplasts constitute an important source of reactive oxygen species (ROS), including hydrogen peroxide. If accumulated at high level, hydrogen peroxide may exert a toxic effect; however, it is as well an important second messenger. In order to balance the toxic and signaling activities of hydrogen peroxide its level has to be tightly con...

  4. 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 ...

  5. 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 ...

  6. (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°.

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

    Directory of Open Access Journals (Sweden)

    Ouarda Dehbi

    2012-04-01

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

  8. 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)

  9. 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)

  10. 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

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    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...... 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...

  12. 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

  13. 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

  14. 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.

  15. 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

  16. INTERACTION OF ALDEHYDES DERIVED FROM LIPID PEROXIDATION AND MEMBRANE PROTEINS.

    Directory of Open Access Journals (Sweden)

    Stefania ePizzimenti

    2013-09-01

    Full Text Available A great variety of compounds are formed during lipid peroxidation of polyunsaturated fatty acids of membrane phospholipids. Among them, bioactive aldehydes, such as 4-hydroxyalkenals, malondialdehyde (MDA and acrolein, have received particular attention since they have been considered as toxic messengers that can propagate and amplify oxidative injury. In the 4-hydroxyalkenal class, 4-hydroxy-2-nonenal (HNE is the most intensively studied aldehyde, in relation not only to its toxic function, but also to its physiological role. Indeed, HNE can be found at low concentrations in human tissues and plasma and participates in the control of biological processes, such as signal transduction, cell proliferation and differentiation. Moreover, at low doses, HNE exerts an anti-cancer effect, by inhibiting cell proliferation, angiogenesis, cell adhesion and by inducing differentiation and/or apoptosis in various tumor cell lines. It is very likely that a substantial fraction of the effects observed in cellular responses, induced by HNE and related aldehydes, be mediated by their interaction with proteins, resulting in the formation of covalent adducts or in the modulation of their expression and/or activity. In this review we focus on membrane proteins affected by lipid peroxidation-derived aldehydes, under physiological and pathological conditions.

  17. 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.

  18. 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

  19. Hydrogen Peroxide and Sodium Transport in the Lung and Kidney

    Directory of Open Access Journals (Sweden)

    V. Shlyonsky

    2016-01-01

    Full Text Available Renal and lung epithelial cells are exposed to some significant concentrations of H2O2. In urine it may reach 100 μM, while in the epithelial lining fluid in the lung it is estimated to be in micromolar to tens-micromolar range. Hydrogen peroxide has a stimulatory action on the epithelial sodium channel (ENaC single-channel activity. It also increases stability of the channel at the membrane and slows down the transcription of the ENaC subunits. The expression and the activity of the channel may be inhibited in some other, likely higher, oxidative states of the cell. This review discusses the role and the origin of H2O2 in the lung and kidney. Concentration-dependent effects of hydrogen peroxide on ENaC and the mechanisms of its action have been summarized. This review also describes outlooks for future investigations linking oxidative stress, epithelial sodium transport, and lung and kidney function.

  20. 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.

  1. 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.

  2. Kinetic release of hydrogen peroxide from different whitening products.

    Science.gov (United States)

    da Silva Marques, Duarte Nuno; Silveira, Joao Miguel; Marques, Joana Rita; Amaral, Joao Almeida; Guilherme, Nuno Marques; da Mata, António Duarte

    2012-01-01

    The objective of this in vitro study was to evaluate the kinetics of hydrogen peroxide (HP) release from five different bleaching products: VivaStyle® 10% fitted tray gel, VivaStyle® 30% in-office bleaching gel, VivaStyle® Paint-On Plus paint-on bleaching varnish, Opalescence PF® 10% carbamide peroxide gel and Trèswhite Supreme™ 10% HP gel. Each product was firstly titrated for its HP content by a described method. HP release kinetics was assessed by a modified spectrophotometric technique. One sample t test was performed to test for differences between the manufacturers' claimed HP concentrations and the titrated HP content in the whitening products. Analysis of variance plus Tamhane's post hoc tests and Pearson correlation analysis were used as appropriate. Values of P tested (P tested. These results are consistent with manufacturers' reduced recommended application times. The results of this study suggest that modifying the matrix composition may be a viable alternative to HP concentration increase, since this may result in faster release kinetics without exposure to high HP concentrations. PMID:22908081

  3. Antifungal efficacy of hydrogen peroxide in dental unit waterline disinfection.

    Science.gov (United States)

    Szymańska, Jolanta

    2006-01-01

    The concentration and composition of fungal flora in dental unit waterlines (DUWL) were evaluated. For this purpose, water samples from unit reservoirs and high-speed handpieces, and biofilm samples from the waterline walls from units were collected. Subsequently, analogous samples from DUWL were taken before and after disinfection using agent containing hydrogen peroxide. In the examined samples, the yeast-like fungi Candida albicans and Candida curvata were found. The following species of mould were also identified: Aspergillus amstelodami, Aspergillus fumigatus, Aspergillus glaucus group, Aspergillus (=Eurotium herbariorum) repens, Citromyces spp., Geotrichum candidum, Penicillium (glabrum) frequentans, Penicillium pusillum, Penicillium turolense and Sclerotium sclerotiorum (Sclerotinia sclerotiorum). Before disinfection, Candida curvata and Candida albicans constituted the greatest proportion of the total fungi in the reservoirs water; in the water of handpieces--Candida albicans and Aspergillus glaucus group; and in the biofilm samples--Aspergillus glaucus group and Candida albicans. After disinfection, in all 3 kinds of samples, Candida albicans prevailed, constituting from 31.2-85.7 % of the total fungi. The application of agent containing hydrogen peroxide caused a significant decrease both in the number of total fungi and individual fungal species, which confirms the product effectiveness in fungal decontamination of DUWL. PMID:17196007

  4. 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.

  5. 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

  6. Photoluminescence of MoS2 quantum dots quenched by hydrogen peroxide: A fluorescent sensor for hydrogen peroxide

    Science.gov (United States)

    Gan, Zhixing; Gui, Qingfeng; Shan, Yun; Pan, Pengfei; Zhang, Ning; Zhang, Lifa

    2016-09-01

    By cutting MoS2 microcrystals to quantum dots (QDs) of sizes below 10 nm, the photoluminescence (PL) at ca. 450 nm can be detected easily due to the quantum confinement effects across the 2D planes. The PL is stable under continuous irradiation of UV light but gradually quenches when treated with an increasing concentration of hydrogen peroxide. Time-resolved PL and Raman spectra imply that H2O2 causes the partial oxidation of MoS2 QDs. First-principles calculations reveal that the MoS2 QDs with oxygen impurity are of indirect bandgap structures showing no notable PL. And absorption spectra verify that the PL of MoS2 QDs quenched by H2O2 is attributed to the oxidation. The integrated PL intensity and H2O2 concentration show an exponential relationship in the range of 2-20 μM, suggesting that MoS2 QDs are potential fluorescent probes for hydrogen peroxide sensing in a physiological environment.

  7. 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

  8. 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

  9. 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...

  10. N-acetylcysteine and hemodialysis treatment of a severe case of methyl ethyl ketone peroxide intoxication

    NARCIS (Netherlands)

    van Enckevort, C C G; Touw, D J; Vleming, L-J

    2008-01-01

    The plastic hardener methyl ethyl ketone peroxide (MEKP) is an unstable peroxide that releases free oxygen radicals. Ingestion of this compound induces widespread liver necrosis that is often fatal, extensive ulceration with subsequent scarring, and stenosis of the proximal digestive tract in surviv

  11. Overoxidation of chloroplast 2-Cys peroxiredoxins: balancing toxic and signaling activities of hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Leonor ePuerto-Galán

    2013-08-01

    Full Text Available Photosynthesis, the primary source of biomass and oxygen into the biosphere, involves the transport of electrons in the presence of oxygen and, therefore, chloroplasts constitute an important source of reactive oxygen species (ROS, including hydrogen peroxide. If accumulated at high level, hydrogen peroxide may exert a toxic effect; however, it is as well an important second messenger. In order to balance the toxic and signaling activities of hydrogen peroxide its level has to be tightly controlled. To this end, chloroplasts are equipped with different antioxidant systems such as 2-Cys peroxiredoxins (2-Cys Prxs, thiol-based peroxidases able to reduce hydrogen- and organic peroxides. At high peroxide concentrations the peroxidase function of 2-Cys Prxs may become inactivated through a process of overoxidation. This inactivation has been proposed to explain the signaling function of hydrogen peroxide in eukaryotes, whereas in prokaryotes, the 2-Cys Prxs of which were considered to be insensitive to overoxidation, the signaling activity of hydrogen peroxide is less relevant. Here we discuss the current knowledge about the mechanisms controlling 2-Cys Prx overoxidation in chloroplasts, organelles with an important signaling function in plants. Given the prokaryotic origin of chloroplasts, we discuss the occurrence of 2-Cys Prx overoxidation in cyanobacteria with the aim of identifying similarities between chloroplasts and their ancestors regarding their response to hydrogen peroxide.

  12. Overoxidation of chloroplast 2-Cys peroxiredoxins: balancing toxic and signaling activities of hydrogen peroxide.

    Science.gov (United States)

    Puerto-Galán, Leonor; Pérez-Ruiz, Juan M; Ferrández, Julia; Cano, Beatriz; Naranjo, Belén; Nájera, Victoria A; González, Maricruz; Lindahl, Anna M; Cejudo, Francisco J

    2013-01-01

    Photosynthesis, the primary source of biomass and oxygen into the biosphere, involves the transport of electrons in the presence of oxygen and, therefore, chloroplasts constitute an important source of reactive oxygen species, including hydrogen peroxide. If accumulated at high level, hydrogen peroxide may exert a toxic effect; however, it is as well an important second messenger. In order to balance the toxic and signaling activities of hydrogen peroxide its level has to be tightly controlled. To this end, chloroplasts are equipped with different antioxidant systems such as 2-Cys peroxiredoxins (2-Cys Prxs), thiol-based peroxidases able to reduce hydrogen and organic peroxides. At high peroxide concentrations the peroxidase function of 2-Cys Prxs may become inactivated through a process of overoxidation. This inactivation has been proposed to explain the signaling function of hydrogen peroxide in eukaryotes, whereas in prokaryotes, the 2-Cys Prxs of which were considered to be insensitive to overoxidation, the signaling activity of hydrogen peroxide is less relevant. Here we discuss the current knowledge about the mechanisms controlling 2-Cys Prx overoxidation in chloroplasts, organelles with an important signaling function in plants. Given the prokaryotic origin of chloroplasts, we discuss the occurrence of 2-Cys Prx overoxidation in cyanobacteria with the aim of identifying similarities between chloroplasts and their ancestors regarding their response to hydrogen peroxide.

  13. 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

  14. 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...

  15. PRECIPITATION OF URANIUM PEROXIDE OF LOW FLUORIDE CONTENT FROM SOLUTIONS CONTAINING FLUORIDES

    Science.gov (United States)

    King, E.J.; Clark, H.M.

    1958-08-12

    S>A method is described for the preparation of fluoride free uraniunn peroxide precipitates, even though the solution from which the precipitation is made is contaminated with fluorides. This is accomplished by add ing aluminum ions to the solution, where they complex any fluoride present and prevent its precipitation with the uramum peroxide.

  16. 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.

  17. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents

    Directory of Open Access Journals (Sweden)

    Mohammad E. Rokaya

    2015-01-01

    Full Text Available Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n=27 according to the bleaching materials used. Each main group was divided into three subgroups (n=9 according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide, group 2 (35% carbamide peroxide, group 3 (sodium perborate-30% hydrogen peroxide mixture, and group 4 (sodium perborate-water mixture. Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey’s test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide.

  18. Contact Lens Solutions With Hydrogen Peroxide: To Avoid Injury, Follow All Instructions

    Science.gov (United States)

    ... should never put hydrogen peroxide directly into your eyes or on your contact lenses,” Lepri says. That’s because this kind of solution ... for Solutions With Hydrogen Peroxide Talk to your eye-care provider ... for your contact lenses. Never change your lens-care system before consulting ...

  19. 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

  20. 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.

  1. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Science.gov (United States)

    2010-04-01

    ... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Silver nitrate and hydrogen peroxide solution. 172.167 Section 172.167 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  2. 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.

  3. 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.

  4. 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...

  5. A Norsesterterpene Peroxide from a Marine Sponge Hippospongia sp.

    Science.gov (United States)

    Su, Ching-chyuan; Su, Huey-jen; Liang, Kai-ju; Tsaif, Su-june; Su, Jui-hsin

    2016-04-01

    One new norsesterterpene peroxide, rhopaloic acid H (1), along with two known related metabolites 2 and 3, were isolated from a marine sponge Hippospongia sp. The structures of compounds were elucidated by means of IR, MS, and NMR techniques and comparison of the NMR data with those of known analogues. Evaluation of the cytotoxicities revealed that compound 2 exhibited significant cytotoxicity against DLD-1, Molt 4, T47D and K-562 cell lines, with IC50 values of 3.18, 0.69, 2.22 and 1.06 µg/mL, respectively. Moreover, compound 3 also showed significant K562 inhibitory activity, with IC50 value of 3.65 µg/mL.

  6. 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.

  7. 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

  8. In vitro antibacterial effect of carbamide peroxide on oral biofilm

    Directory of Open Access Journals (Sweden)

    Chao Shu Yao

    2013-06-01

    Full Text Available This study compared the effects of carbamide peroxide (CP and chlorhexidine (CHX on oral biofilm in vitro. Collagen-coated hydroxyapatite discs were inoculated with subgingival plaque. After 3 weeks, the emergent biofilms were subjected to 1-, 3-, and 10-min exposures of a 1% CHX gel, a 5% CP gel and rinse, and a 10% CP gel and rinse. Subsequently, the biofilms were stained using a two-colour fluorescent dye kit for confocal laser scanning microscopy, and the volume ratio of dead bacteria to all bacteria was analysed. Compared to a non-treated gel control, the active agents killed bacteria on all the discs, with higher concentration and longer exposure times killing more bacteria. The rinse form disrupted the biofilm quicker than the gel form. Overall, 10% CP showed more disruption of biofilm and a greater proportion of killed bacteria than 1% CHX (p<0.05.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Effects of resveratrol on hydrogen peroxide-induced oxidative stress in embryonic neural stem cells

    Institute of Scientific and Technical Information of China (English)

    Sibel Konyalioglu; Guliz Armagan; Ayfer Yalcin; Cigdem Atalayin; Taner Dagci

    2013-01-01

    Resveratrol, a natural phenolic compound, has been shown to prevent cardiovascular diseases and cancer and exhibit neuroprotective effects. In this study, we examined the neuroprotective and antioxidant effects of resveratrol against hydrogen peroxide in embryonic neural stem cells. Hydrogen peroxide treatment alone increased catalase and glutathione peroxidase activities but did not change superoxide dismutase levels compared with hydrogen peroxide + resveratrol treatment. Nitric oxide synthase activity and concomitant nitric oxide levels increased in response to hydrogen peroxide treatment. Conversely, resveratrol treatment decreased nitric oxide synthase activity and nitric oxide levels. Resveratrol also attenuated hydrogen peroxide-induced nuclear or mitochondrial DNA damage. We propose that resveratrol may be a promising agent for protecting embryonic neural stem cells because of its potential to decrease oxidative stress by inducing higher activity of antioxidant enzymes, decreasing nitric oxide production and nitric oxide synthase activity, and alleviating both nuclear and mitochondrial DNA damage.

  14. Chemiluminescent Nanomicelles for Imaging Hydrogen Peroxide and Self-Therapy in Photodynamic Therapy

    Directory of Open Access Journals (Sweden)

    Rui Chen

    2011-01-01

    Full Text Available Hydrogen peroxide is a signal molecule of the tumor, and its overproduction makes a higher concentration in tumor tissue compared to normal tissue. Based on the fact that peroxalates can make chemiluminescence with a high efficiency in the presence of hydrogen peroxide, we developed nanomicelles composed of peroxalate ester oligomers and fluorescent dyes, called peroxalate nanomicelles (POMs, which could image hydrogen peroxide with high sensitivity and stability. The potential application of the POMs in photodynamic therapy (PDT for cancer was also investigated. It was found that the PDT-drug-loaded POMs were sensitive to hydrogen peroxide, and the PDT drug could be stimulated by the chemiluminescence from the reaction between POMs and hydrogen peroxide, which carried on a self-therapy of the tumor without the additional laser light resource.

  15. Organic peroxide production in the Cl2-ethane-air photoreaction system

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    HPLC along with FT-IR technique was used to study the formationof organic peroxides in the Cl2-ethane-air photoreaction system. Ethyl hydroperoxide (CH3CH2OOH, EHP) and peroxyacetic acid ( CH3C(O)OOH, PAA) were conformed to be the peroxide product in the reaction system. In addition, methyl hydroperoxide (CH3OOH, MHP), hydroxymethyl hydroperoxide (HOCH2OOH, HMHP) and two unidentified organic peroxides were detected for the first time. EHP and MHP were the dominant peroxide products. The identification of HMHP showed that Criegee biradical CH2OO may be formed as an intermediate in the oxidation of ethane. Simulation results showed that photo-oxidation of ethane may make substantial contribution to source of organic peroxides in the atmos-phere.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Repetitive Peroxide Exposure Reveals Pleiotropic Mitogen-Activated Protein Kinase Signaling Mechanisms

    Directory of Open Access Journals (Sweden)

    Wayne Chadwick

    2011-01-01

    Full Text Available Oxidative stressors such as hydrogen peroxide control the activation of many interconnected signaling systems and are implicated in neurodegenerative disease etiology. Application of hydrogen peroxide to PC12 cells activated multiple tyrosine kinases (c-Src, epidermal growth factor receptor (EGFR, and Pyk2 and the serine-threonine kinase ERK1/2. Peroxide-induced ERK1/2 activation was sensitive to intracellular calcium chelation and EGFR and c-Src kinase inhibition. Acute application and removal of peroxide allowed ERK1/2 activity levels to rapidly subside to basal serum-deprived levels. Using this protocol, we demonstrated that ERK1/2 activation tachyphylaxis developed upon repeated peroxide exposures. This tachyphylaxis was independent of c-Src/Pyk2 tyrosine phosphorylation but was associated with a progressive reduction of peroxide-induced EGFR tyrosine phosphorylation, EGFR interaction with growth factor receptor binding protein 2, and a redistribution of EGFR from the plasma membrane to the cytoplasm. Our data indicates that components of peroxide-induced ERK1/2 cascades are differentially affected by repeated exposures, indicating that oxidative signaling may be contextually variable.

  4. 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

  5. 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.

  6. Arsenic increased lipid peroxidation in rat tissues by a mechanism independent of glutathione levels.

    Science.gov (United States)

    Ramos, O; Carrizales, L; Yáñez, L; Mejía, J; Batres, L; Ortíz, D; Díaz-Barriga, F

    1995-01-01

    The role of lipid peroxidation in the mechanism of arsenic toxicity was investigated in female rats pretreated with N-acetylcysteine (NAC, a glutathione [GSH] inducer) or with buthionine sulfoximine (BSO, a GSH depletor). Rats were challenged with sodium arsenite, and sacrificed 1 hr after this treatment. Results showed that arsenic decreased GSH levels and increased lipid peroxidation in liver, kidney, and heart, with a larger effect at 18.2 mg/kg than at 14.8 mg/kg for lipid peroxidation induction. In the liver of rats treated with arsenic, pretreatment with NAC increased the levels of GSH and decreased lipid peroxidation. In kidney and heart, NAC pretreatment protected the tissues against arsenic-induced depletion of GSH levels, but the same degree of protection was not found for lipid peroxidation induction. In its turn, BSO had an additive effect with arsenic in lowering the levels of GSH in the liver and kidney, but an inverse correlation between GSH levels and lipid peroxidation was found only in liver. Arsenic content in tissues of rats pretreated with NAC was lower than in rats treated only with arsenic. In rats with depleted levels of GSH (BSO-pretreated rats), a shift in arsenic tissue distribution was found, with higher levels in skin and lower levels in kidney. A clear tendency for a positive correlation between arsenic concentration and lipid peroxidation levels was found in liver, kidney, and heart. PMID:7621808

  7. 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.

  8. 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.

  9. 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.

  10. Hydrogen peroxide in exhaled breath condensate: A clinical study

    Directory of Open Access Journals (Sweden)

    C Nagaraja

    2012-01-01

    Full Text Available Objectives: To study the ongoing inflammatory process of lung in healthy individuals with risk factors and comparing with that of a known diseased condition. To study the inflammatory response to treatment. Background: Morbidity and mortality of respiratory diseases are raising in trend due to increased smokers, urbanization and air pollution, the diagnosis of these conditions during early stage and management can improve patient′s lifestyle and morbidity. Materials and Methods: One hundred subjects were studied from July 2010 to September 2010; the level of hydrogen peroxide concentration in exhaled breath condensate was measured using Ecocheck. Results: Of the 100 subjects studied, 23 were healthy individuals with risk factors (smoking, exposure to air pollution, and urbanization; the values of hydrogen peroxide in smokers were 200-2220 nmol/l and in non-smokers 340-760 nmol/l. In people residing in rural areas values were 20-140 nmol/l in non-smokers and 180 nmol/l in smokers. In chronic obstructive pulmonary disease cases, during acute exacerbations values were 540-3040 nmol/l and 240-480 nmol/l following treatment. In acute exacerbations of bronchial asthma, values were 400-1140 nmol/l and 100-320 nmol/l following treatment. In cases of bronchiectasis, values were 300-340 nmol/l and 200-280 nmol/l following treatment. In diagnosed pneumonia cases values were 1060-11800 nmol/l and 540-700 nmol/l following treatment. In interstitial lung diseases, values ranged from 220-720 nmol/l and 210-510 nmol/l following treatment. Conclusion: Exhaled breath condensate provides a non-invasive means of sampling the lower respiratory tract. Collection of exhaled breath condensate might be useful to detect the oxidative destruction of the lung as well as early inflammation of the airways in a healthy individual with risk factors and comparing the inflammatory response to treatment.

  11. 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...

  12. 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

  13. Salidroside inhibits endogenous hydrogen peroxide induced cytotoxicity of endothelial cells.

    Science.gov (United States)

    Zhao, Xingyu; Jin, Lianhai; Shen, Nan; Xu, Bin; Zhang, Wei; Zhu, Hongli; Luo, Zhengli

    2013-01-01

    Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L., shows potent antioxidant property. Herein, we investigated the protective effects of salidroside against hydrogen peroxide (H2O2)-induced oxidative damage in human endothelial cells (EVC-304). EVC-304 cells were incubated in the presence or absence of low steady states of H2O2 (3-4 µM) generated by glucose oxidase (GOX) with or without salidroside. 3(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) assays were performed, together with Hoechst 33258 staining and flow cytometric analysis using Annexin-V and propidium iodide (PI) label. The results indicated that salidroside pretreatment attenuated endogenous H2O2 induced apoptotic cell death in EVC-304 cells in a dose-dependent pattern. Furthermore, Western blot data revealed that salidroside inhibited activation of caspase-3, 9 and cleavage of poly(ADP-ribose) polymerase (PARP) induced by endogenous H2O2. It also decreased the expression of Bax and rescued the balance of pro- and anti-apoptotic proteins. All these results demonstrated that salidroside may present a potential therapy for oxidative stress in cardiovascular and cerebrovascular diseases.

  14. 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.

  15. Specific aquaporins facilitate the diffusion of hydrogen peroxide across membranes.

    Science.gov (United States)

    Bienert, Gerd P; Møller, Anders L B; Kristiansen, Kim A; Schulz, Alexander; Møller, Ian M; Schjoerring, Jan K; Jahn, Thomas P

    2007-01-12

    The metabolism of aerobic organisms continuously produces reactive oxygen species. Although potentially toxic, these compounds also function in signaling. One important feature of signaling compounds is their ability to move between different compartments, e.g. to cross membranes. Here we present evidence that aquaporins can channel hydrogen peroxide (H2O2). Twenty-four aquaporins from plants and mammals were screened in five yeast strains differing in sensitivity toward oxidative stress. Expression of human AQP8 and plant Arabidopsis TIP1;1 and TIP1;2 in yeast decreased growth and survival in the presence of H2O2. Further evidence for aquaporin-mediated H2O2 diffusion was obtained by a fluorescence assay with intact yeast cells using an intracellular reactive oxygen species-sensitive fluorescent dye. Application of silver ions (Ag+), which block aquaporin-mediated water diffusion in a fast kinetics swelling assay, also reversed both the aquaporin-dependent growth repression and the H2O2-induced fluorescence. Our results present the first molecular genetic evidence for the diffusion of H2O2 through specific members of the aquaporin family.

  16. Structural and magnetic properties nickel/rubrene(peroxide) bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen; Albrecht, Manfred; Zahn, Dietrich R.T.; Salvan, Georgeta [Chemnitz University of Technology (Germany); Springer, Felix [University of Konstanz (Germany). Department of Physics

    2008-07-01

    Bilayers of nickel/rubrene were obtained by sequential deposition of rubrene and Ni onto Si(111) substrate under ultra-high vacuum conditions. Ex situ AFM studies show that the growth mode of Ni is significantly influenced by the thickness of the underlying rubrene layer. When deposited onto a 14 nm rubrene layer Ni forms large islands, hundreds of nanometers in lateral dimension, with large voids between them. On thicker rubrene layers the Ni islands are much smaller forming an almost continuous film. The hysteresis curves recorded ex situ by magneto-optical Kerr effect (MOKE) measurements in polar geometry show that the magnetic properties change according to the different growth modes. The hysteresis behavior of Ni(7nm)/rubrene peroxide(14 nm) shows a combination of ferromagnetic and superparamagnetic behaviour. When the thickness of the rubrene underlayer increases the system behaves ferromagnetically. The spectroscopic MOKE measurements show that the signal intensity and the energetic position of the spectral features are strongly influenced by the rubrene thickness. Compared to the single Ni(7 nm) layer deposited on Si, the MOKE signal of bilayers can be enhanced by about a factor of three.

  17. 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.

  18. 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.

  19. 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.

  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. 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.

  2. Effect of Sodium Metabisulfite on Rat Ovary and Lipid Peroxidation

    Directory of Open Access Journals (Sweden)

    Nahid Rezaee

    2016-02-01

    Full Text Available Background: Many health problems are related to lifestyle and dietary factors. Since ancient times, food additives such as sulfites have been used to preserve foods. Diverse effects of sulfites on multiple organs have been reported but its effect on female reproductive organ has not been fully elucidated. The aim of this study was to investigate the effects of sodium metabisulfite (SMB on ovarian tissue in adult rats. Methods: Four groups of female rats (n=32 were used. The experimental rats received 10, 100 and 260 mg/kg SMB for 28 days (S10, S100 and S260 groups, respectively. The control rats received distilled water for the same period. The ovarian volume, weight and the number of different types of follicles were estimated by stereological methods. Lipid peroxidation is assessed indirectly by the measurement of malondialdehyde (MDA, using the thiobarbituric acid (TBA method. Results: The results showed a significant decrease in the ovarian volume, the number of primordial, primary, secondary, grafian follicles and corpus luteum in the SMB-treated animals compared with the control group (P < 0.05. In comparison to the control group, the number of atretic follicles increased in the SMB-treated rats. MDA was significantly increased in S260 group compared to the control group. Conclusion: The present data confirm sulfite-induced structural changes in the ovary. Increased level of MDA because of SMB ingestion suggests that free radicals may have a critical role in these changes.

  3. Simultaneous electroanalysis of peroxyacetic acid and hydrogen peroxide.

    Science.gov (United States)

    Awad, M I; Harnoode, C; Tokuda, K; Ohsaka, T

    2001-04-15

    The electrochemical behavior of peroxyacetic acid (PAA) in the presence of hydrogen peroxide (H2O2) has been investigated using cyclic voltammetry and hydrodynamic techniques [rotating disk electrode (RDE) voltammetry and rotating ring-disk electrode (RRDE) voltammetry]. The results have been analyzed aiming at simultaneous electroanalysis of both species. Glassy carbon and gold electrodes were used for this investigation. It was found that the reduction of PAA, as well as H2O2, is highly sensitive to the electrode material; for example, at 100 mV s-1, the reduction peak potentials of PAA were 0.2 and -1.1 V at gold and glassy carbon electrodes, respectively. The well-separated steady-state limiting currents were obtained using a gold electrode for the reduction of both PAA and H2O2 and also a well-defined one for the oxidation of H2O2. On the basis of the RDE experiments, good calibration curves were obtained for both species over a wide range of their concentrations, for PAA and H2O2 in the range of 0.36 to 110 and 0.11 to 34 mM, respectively. The simultaneous and selective electroanalysis of PAA and H2O2 in their coexistence is demonstrated for the first time.

  4. 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.

  5. 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

  6. Solvothermal method to prepare graphene quantum dots by hydrogen peroxide

    Science.gov (United States)

    Tian, Renbing; Zhong, Suting; Wu, Juan; Jiang, Wei; Shen, Yewen; Jiang, Wei; Wang, Tianhe

    2016-10-01

    Graphene quantum dots (GQDs) have been synthesized by different chemical methods in recent years. For conventional chemical methods, it is inevitable to introduce a large amount of impurities in the preparation process. Long time of dialysis process increases the time cost extremely. Herein, we report a one-step solvothermal method for synthesizing GQDs with the application of hydrogen peroxide in N, N-Dimethylformamide (DMF) environment, which completely avoids the use of concentrated sulphuric acid and nitric acid to treat raw material and introduces no impurity in whole preparation process simultaneously for the first time. Pure GQDs can be obtained after evaporation/redissolution and filtration process with a strong blue emission at 15% quantum yield. This solvothermal method, not requiring dialysis process and complicated equipments, exhibits simple, eco-friendly and low time-cost properties. Besides high quantum yields, the as-prepared GQDs also show good photoluminescence stability in different pH conditions. The optical properties, morphology and structure of GQDs were studied by various equipments, implying potential application in biomedical fields and electronic device.

  7. SIMULTANEOUS REACTION AND LIQUID-LIQUID EXTRACTION IN THE HYDROGEN PEROXIDE PRODUCTION

    Institute of Scientific and Technical Information of China (English)

    Shuxiang L(u); Li Wang; Zhentao Mi; Yaquan Wang

    2004-01-01

    The gas-liquid-liquid reactive extraction system for preparing hydrogen peroxide via anthraquinone was investigated. The oxidation reaction of hydrogenated working solution was combined with the extraction of hydrogen peroxide from working solution in a sieve plate column. The reaction of 2-ethylanthrahydroquionone with oxygen and the liquid-liquid extraction of hydrogen peroxide take place simultaneously. The oxygen was introduced with hydrogenated working solution through a nozzle in the bottom of the column, which worked as agitated air as well as oxidation reagent. The results showed the oxidation and extraction do not hamper each other, on the contrary, the presence of oxidation gas in the column can promote the transfer of hydrogen peroxide from organic phase to aqueous phase, thus the reaction efficiency and extraction efficiency increased with increasing gas superficial velocity. Furthermore, the oxidation efficiency is almost 100% and the extraction efficiency is higher than 90% in this process.

  8. 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.

  9. Glutathione protects liver and kidney tissue from cadmium- and lead-provoked lipid peroxidation

    Directory of Open Access Journals (Sweden)

    Jovanović Jasmina M.

    2013-01-01

    Full Text Available Cd and Pb represent a serious ecological problem due to their soluble nature, their mobility and ability to accumulate in the soil. The exposure to these heavy metals can originate from different sources (drinking water, food, air, and they can make their way into the human body through the respiratory and digestive system. We investigated the effects of glutathione on Cd and Pb accumulation and lipid peroxidation effects in the liver and kidneys of heavy metal intoxicated rats. The content of the marker of lipid peroxidation - malondialdehyde was increased several fold the in tissues of exposed animals, the effects being more pronounced in liver. The treatment of intoxicated animals with glutathione drastically suppressed lipid peroxidation. Our results imply that the application of glutathione may have protective role in heavy metal intoxication by inhibiting lipid peroxidation. However, precaution should be made when it comes to Cd, since it seems that glutathione promoted Cd accumulation in the liver.

  10. 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

    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...... protein can result in selective subsequent damage to other proteins, as evidenced by loss of enzymatic activity, via the formation and subsequent reactions of protein peroxides. These reactions may be important in the development of cellular dysfunction as a result of photo-oxidation.......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...

  11. Protective role of edible clam Paphia malabarica (Chemnitz) against lipid peroxidation and free radicals

    Digital Repository Service at National Institute of Oceanography (India)

    Pawar, R.T.; Nagvenkar, S.S.; Jagtap, T.G.

    In vitro inhibition of lipid peroxidation and free radical scavenging properties of a seafood Paphia malabarica (Chemnitz) as a natural source of antioxidants was observed. Antioxidant activities of Paphia malabarica extracts were tested...

  12. 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).

  13. MICROWAVE-EXPEDITED OLEFIN EPOXIDATION OVER HYDROTALCITES USING HYDROGEN PEROXIDE AND ACETONITRILE

    Science.gov (United States)

    An efficient microwave-assisted expoxidation of olefins is described over hydrotalcite catalysts in the presence of hydrogen peroxide and acetonitrile. This general and selective protocol is extremely fast and is applicable to a wide variety of subtrates.

  14. Effect of x-ray irradiation on lipid peroxide levels in the rat submandibular gland

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, M.; Takashima, H.; Oka, T.; Ohishi, N.; Yagi, K.

    1986-07-01

    We examined the effect of local x-ray irradiation on the changes in the lipid peroxide level in submandibular gland, liver, and blood plasma. Rats five weeks of age received a single low dose of 3 Gy x-ray irradiation to their neck regions. The lipid peroxide level in the submandibular gland was significantly enhanced at seven days after irradiation, as was the level in the blood plasma at two hours, seven and 14 days after irradiation. The lipid peroxide level in the liver decreased, as compared with levels in the controls. There was a slight tendency for acinar cells of the submandibular gland to show pyknosis and anomalous nuclei within three days after irradiation. These results suggest that radiation injury results in an elevation of the lipid peroxides in the submandibular gland, and an increased level in the blood.

  15. 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}).

  16. 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.

  17. Influence of cosmic radiationon lymphocyte micronucleus,serum lipid peroxide and antioxidation capacity inaircrew members

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This study looks into the influence of cosmic radiation at high altitudes on human bodies. Results reveal that the cytokinesis-block micronuclei (CBMN) and conventional cultured micronuclei in peripheral blood lymphocytes, serum levels of lipid peroxide, superoxide dismutase, and the total antioxidation capacity by chemical colorimetry all increased significantly in aircrew members. There exists a linear relationship between the CBMN and the average annual effective doses of radiation received or the average annual flying hours. With both of them, a trend shows that the serum lipid peroxide levels increase as well. Either the lipid peroxide or CBMN can sensitively reflect the recent changes in flight load. These findings indicate that cosmic radiation impairs the stability of chromosomes and genome, and induces lipid oxidative damage in aircrews; Lymphocyte CBMN and serum lipid peroxide can be used as monitoring indicators in the cosmic radiation protection for aircrew members.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Chemistry; Smith, B.F. [Los Alamos National Lab., NM (United States)

    1991-11-01

    The first measurements of distribution coefficients (K{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}`s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}`s for these actinides are about a factor of 5 to 10 greater than the K{sub d}`s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}`s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand.

  3. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Chemistry); Smith, B.F. (Los Alamos National Lab., NM (United States))

    1991-11-01

    The first measurements of distribution coefficients (K{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}'s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}'s for these actinides are about a factor of 5 to 10 greater than the K{sub d}'s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}'s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand.

  4. Separation studies of yttrium(III) and lanthanide(III) ions with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and trioctylphosphine oxide using a robotic extraction system

    Energy Technology Data Exchange (ETDEWEB)

    Nekimken, H.L.; Smith, B.F.; Jarvinen, G.D.; Bartholdi, C.S. [Los Alamos National Lab., NM (United States)

    1992-07-01

    We studied the extraction of trivalent Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Er, and Lu from aqueous perchlorate solutions using a mixture of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (HBMPPT) and trioctylphosphine oxide (TOPO). The metal ion distribution coefficients (D-values) as a function of increasing lanthanide atomic number increased initially, reached a maximum value at Nd, then decreased to a nearly constant value for Gd and the later lanthanides. The D-values vary slightly across the lanthanide series, the maximum difference being a factor of 14 between La and Nd. Analysis of slopes of plots of log D versus pH, log [HBMPPT], and log [TOPO] indicated that the stoichiometries of the extraction complexes varied across the lanthanide series showing a decrease in the number of HBMPPT (and/or BMPPT) units and an increase in the number of TOPO molecules involved in the major extraction species. This extraction system can provide a good way to separate the trivalent actinides from the trivalent lanthanides. 21 refs., 2 figs., 3 tabs.

  5. Extraction studies of selected actinide ions from aqueous solutions with 4-benzoyl-2,4-Dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and Tri-n-octylphosphine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hannink, N.J.; Hoffman, D.C. [Lawrence Berkeley Lab., CA (United States); Smith, B.F. [Los Alamos National Lab., NM (United States)

    1992-07-01

    The first measurements of distribution coefficients (k{sub d}) for Cm(III), Bk(III), Cf(III), Es(III), and Fm(III) between aqueous perchlorate solutions and solutions of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT) and the synergist tri-n-octylphosphine oxide (TOPO) in toluene are reported. Curium-243, berkelium-250, californium-249, einsteinium-254, and fermium-253 were used in these studies. The K{sub d} for {sup 241}Am was also measured and is in agreement with previously published results. Our new results show that the K{sub d}`s decrease gradually with increasing atomic number for the actinides with a dip at Cf. In general, the K{sub d}`s for these actinides are about about a factor of 10 greater than the K{sub d}`s for the homologous lanthanides at a pH of 2.9, a BMPPT concentration of 0.2 M, and a TOPO concentration of 0.04 M. The larger K{sub d}`s for the actinides are consistent with greater covalent bonding between the actinide metal ion and the sulfur bonding site in the ligand. 9 refs., 2 figs., 1 tab.

  6. 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...

  7. 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 ...

  8. 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...

  9. Lipid peroxidation - inhibitory effects of perioperatively used drugs associated with their membrane interactions.

    OpenAIRE

    Tsuchiya, Hironori

    2014-01-01

    Objective: Oxidative/nitrative stress, an imbalance between oxidant production and antioxidant defense in the biological system, is induced not only by various diseases but also by anesthesia and surgical trauma. Since the choice of drugs is expected to reduce oxidative/nitrative stress in the perioperative period, the lipid peroxidation inhibition by different drugs associated with surgery was studied together with investigating one of their possible mechanisms.Methods: Lipid peroxidation-in...

  10. Spectrophotometric Evaluation of the Pulpal Peroxide Levels in Intact and Restored Teeth - An Invitro Study

    Science.gov (United States)

    Acharya, Gourismita; Agrawal, Pratik; Panda, Vijeta

    2016-01-01

    Introduction Hydrogen peroxide (30%) is a commonly used "in office" bleaching agent. Deleterious effects of hydrogen peroxide on the pulp have been observed. Aim The present study was conducted with the aim to evaluate the penetration of 30% hydrogen peroxide into the pulp chamber through intact teeth and through the surface of teeth, restored with either hybrid composite or Resin Modified Glass Ionomer Cement (RMGIC). Materials and Methods Sixty extracted human maxillary central incisors were selected and divided into six groups. Two groups were restored with hybrid composite resin and two with RMGIC, while two groups were left intact. The teeth with acetate buffer solution in their pulp cavity were then immersed in either 30% hydrogen peroxide or distilled water depending upon the group, for 60 minutes at 37°C. Then horseradish peroxidase and leucocrystal violet were added to the acetate buffer solution present in the pulp chamber after it was transferred to a test tube and the optical density of the resultant blue solution obtained was measured spectrophotometrically. Statistical Analysis The data obtained were analyzed using one way ANOVA and Student’s t-test. Results The data obtained established that hydrogen peroxide penetrated into the pulp from the bleaching agent used. Hydrogen peroxide (30%) showed the highest pulpal peroxide level in teeth restored with RMGIC followed by teeth restored with hybrid composite resin and the least amount of penetration was observed in intact teeth. Conclusion The amount of peroxide penetration into the tooth is more through restored tooth than intact tooth and is also dependant on the type of restorative materials used. PMID:27656562

  11. The application of catalase for the elimination of hydrogen peroxide residues after bleaching of cotton fabrics

    Directory of Open Access Journals (Sweden)

    AMORIM ALEXANDRA M.

    2002-01-01

    Full Text Available Results of dyeing of cotton fabrics with a bifunctional reactive dye were significantly improved when the fabric after bleaching with hydrogen peroxide was treated with catalase for the elimination of hydrogen peroxide residues from the fabrics. Compared to processes with a varying number of washing steps, with and without commercial reducing agents, the consumption of water could be significantly reduced, without altering the final color shade.

  12. 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 ...

  13. 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...

  14. 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...

  15. 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].

  16. 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

  17. 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 ...

  18. Peroxide-dependent MGL sulfenylation regulates 2-AG-mediated endocannabinoid signaling in brain neurons

    OpenAIRE

    Dotsey, Emmanuel Y.; Jung, Kwang-Mook; Basit, Abdul; Wei, Don; Daglian, Jennifer; Vacondio, Federica; Armirotti, Andrea; Mor, Marco; Piomelli, Daniele

    2015-01-01

    The second messenger hydrogen peroxide transduces changes in cellular redox state by reversibly oxidizing protein cysteine residues to sulfenic acid. This signaling event regulates many cellular processes, but has been never shown to occur in the brain. Here we report that hydrogen peroxide heightens endocannabinoid signaling in brain neurons through sulfenylation of cysteines C201 and C208 in monoacylglycerol lipase (MGL), a serine hydrolase that deactivates the endocannabinoid 2-arachidonoy...

  19. 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 ...

  20. 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...

  1. In vitro inhibition of lipid peroxidation in fish by turmeric (Curcuma longa)

    OpenAIRE

    D'Souza, Hilda Priya; Prabhu, H. Ramachandra

    2006-01-01

    The beneficial effects of ∈-3 fatty acids on human health have been well documented. Fish and fish oils are the richest sources of ∈-3 fatty acids. However, due to their high degree of unsaturation, they are highly susceptible to lipid peroxidation. Regular consumption of peroxidised oils may represent a risk factor for the induction and development of atherosclerosis. In view of the above reports, it was considered necessary to study the effects of tumeric on fish lipid peroxidation during s...

  2. 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...

  3. 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.

  4. 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.

  5. 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...

  6. Antioxidant and anti-lipid peroxidation activities of Tamarindus indica seed coat in human fibroblast cells.

    Science.gov (United States)

    Nakchat, Oranuch; Meksuriyen, Duangdeun; Pongsamart, Sunanta

    2014-02-01

    Antioxidant activity and total phenolic content of tamarind seed coat extracts (TSCEs) were compared between the two extracts using boiling-water (TSCE-W) and 70% ethanol (TSCE-E) for extraction. TSCE-W, consisting of the highest phenolic content, possessed 2,2-diphenyl-1 -picrylhydrazyl (DPPH) radical scavenging and anti-lipid peroxidation activities much higher than TSCE-E and Trolox. Additionally, both TSCEs also exhibited superoxide anion and hydrogen peroxide scavenging activities higher than Trolox and BHA. Anti-lipid peroxidation and cytotoxicity of TSCE-W were also studied in human foreskin fibroblast CCD-1064Sk cells. Cytotoxic effect was not observed when exposed to TSCE-W up to 1 mg/mL for 12-48 h. However, TSCE-W significantly attenuated lipid peroxidation in H202-damaged cells. HPLC analysis showed the presence of (+)-catechin, (-)-epicatechin, and procyanidin B2 in TSCE-W, which could be responsible for antioxidant and anti-lipid peroxidation activities. The results suggest that an inexpensive and simple boiling-water extraction of TSCE-W may provide a valuable natural antioxidant source having anti-lipid peroxidation for health food additives, nutraceuticals as well as cosmeceuticals.

  7. 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

  8. 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

  9. Boronate-based fluorescent probes: imaging hydrogen peroxide in living systems.

    Science.gov (United States)

    Lin, Vivian S; Dickinson, Bryan C; Chang, Christopher J

    2013-01-01

    Hydrogen peroxide, a reactive oxygen species with unique chemical properties, is produced endogenously in living systems as a destructive oxidant to ward off pathogens or as a finely tuned second messenger in dynamic cellular signaling pathways. In order to understand the complex roles that hydrogen peroxide can play in biological systems, new tools to monitor hydrogen peroxide in its native settings, with high selectivity and sensitivity, are needed. Knowledge of organic synthetic reactivity provides the foundation for the molecular design of selective, functional hydrogen peroxide probes. A palette of fluorescent and luminescent probes that react chemoselectively with hydrogen peroxide has been developed, utilizing a boronate oxidation trigger. These indicators offer a variety of colors and in cellulo characteristics and have been used to examine hydrogen peroxide in a number of experimental setups, including in vitro fluorometry, confocal fluorescence microscopy, and flow cytometry. In this chapter, we provide an overview of the chemical features of these probes and information on their behavior to help researchers select the optimal probe and application.

  10. MODIFIED OPAL: A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

    Institute of Scientific and Technical Information of China (English)

    XuerenQian; XianhuiAn; WenboLiu; GangYu; ZhanqianSong

    2004-01-01

    The possibility of modified opal as the stabilizer ofhydrogen peroxide bleaching was investigated. Theresults showed that the modified opal in place ofsodium silicate as the stabilizer of hydrogen peroxidebleaching is feasible. At the same dosage, above 3%ISO can be increased for both wheat straw pulp anddeinked pulp. The stabilizing ability of the modifiedopal to hydrogen peroxide bleaching of pulp isimproved markedly. It is favorable for bleaching toincrease temperature and time within a permissiveextent. The suitable process conditions are I0% ofpulp consistency, 3% of hydrogen peroxide, 1.5% ofsodium hydroxide, 3% of the modified opal, 70~"and 60 min when the modified opal is used as thestabilizer of hydrogen peroxide bleaching. At theseconditions, the brightness gain can reach about 16%ISO for wheat straw pulp. In addition, it is favorablefor bleaching to add a little magnesium sulfate whenthe modified opal is used as the stabilizer ofhydrogen peroxide bleaching, the brightness of pulpcan increase 1%ISO if0.05% of magnesium sulfate isadded. The cost analysis indicated that the modifiedopal is superior to sodium silicate as the stabilizer ofhydrogen peroxide bleaching in economical aspectand has further the potential of market development.

  11. Effects of hydrogen peroxide on mitochondrial gene expression of intestinal epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Jian-Ming Li; Qian Cai; Hong Zhou; Guang-Xia Xiao

    2002-01-01

    AIM: To study the effects of hydrogen peroxide on mitochondrial gene expression of intestinal epithelial cells in in vitro model of hydrogen peroxide-stimulated SW-480 cells.METHODS: RNA of hydrogen peroxide-induced SW-480 cells was isolated, and reverse-transcriptional polymerase chain reaction was performed to study gene expression of ATPase subunit 6, ATPase subunit 8, cytochrome c oxidase subunit Ⅰ (COⅠ), cytochrome coxidase subuit Ⅱ (COⅡ) and cytochrome c oxidase subunit Ⅲ (COⅢ). Mitochondria were isolated and activities of mitochondrial cytochrome c oxidase and ATPase were also measured simultaneously.RESULTS: Hydrogen peroxide led to differential expression of mitochondrial genes with some genes up-regulated or down-regulated in a dose dependent manner. Differences were very obvious in expressions of mitochondrial genes of cells treated with hydrogen peroxide in a concentration of 400 μmol/L or 4 mmol/L. In general, differential expression of mitochondrial genes was characterized by up-regulation of mitochondrial genes in the concentration of 400 μmol/L and down-regulation in the concentration of 4 mmol/L. In consistence with changes in mitochondrial gene expressions, hydrogen peroxide resulted in decreased activities of cytochrome c oxidase and ATPase.CONCLUSIONS: The differential expression of mitochondrial genes encoding cytochrome c oxidase and ATPase is involved in apoptosis of intestinal epithelial cells by affecting activities of cytochorme c oxidase and ATPase.

  12. 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

  13. 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.

  14. Shock initiation studies on high concentration hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, Stephen A [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Stahl, David B [Los Alamos National Laboratory; Gibson, L. Lee [Los Alamos National Laboratory; Bartram, Brian D. [Los Alamos National Laboratory

    2009-01-01

    Concentrated hydrogen peroxide (H{sub 2}O{sub 2}) has been known to detonate for many years. However, because of its reactivity and the difficulty in handling and confining it, along with the large critical diameter, few studies providing basic information about the initiation and detonation properties have been published. We are conducting a study to understand and quantify the initiation and detonation properties of highly concentrated H{sub 2}O{sub 2} using a gas-driven two-stage gun to produce well defined shock inputs. Multiple magnetic gauges are used to make in-situ measurements of the growth of reaction and subsequent detonation in the liquid. These experiments are designed to be one-dimensional to eliminate any difficulties that might be encountered with large critical diameters. Because of the concern of the reactivity of the H{sub 2}O{sub 2} with the confining materials, a remote loading system has been developed. The gun is pressurized, then the cell is filled and the experiment shot within less than three minutes. TV cameras are attached to the target so the cell filling can be monitored. Several experiments have been completed on {approx}98 wt % H{sub 2}O{sub 2}/H{sub 2}O mixtures; initiation has been observed in some experiments that shows homogeneous shock initiation behavior. The initial shock pressurizes and heats the mixture. After an induction time, a thermal explosion type reaction produces an evolving reactive wave that strengthens and eventually overdrives the first wave producing a detonation. From these measurements, we have determined unreacted Hugoniot information, times (distances) to detonation (Pop-plot points) that indicate low sensitivity, and detonation velocities of high concentration H{sub 2}O{sub 2}/H{sub 2}O solutions that agree with earlier estimates.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. Possible role of organic peroxides in the detection of irradiated food

    Energy Technology Data Exchange (ETDEWEB)

    Qi Shengchu; Wu Jilan (Beijing Univ., BJ (China). Dept. of Technical Physics); Zhu Yan (Ministry of Public Health, Beijing (China))

    In order to determine the level of organic peroxides induced by autooxidation, random sampling of pork has been performed. The organic peroxide content in unirradiated pork has been estimated as (5.4 [+-] 3.0) x10[sup -5]mol.kg[sup -1]. The dependence of yield of peroxide in pork, minced meat and braised chicken on absorbed dose has been investigated. For killing trichinae 0.5 [approx] 1 kGy is used, the quantity of peroxide in pork will be 4x10[sup -4] mol.kg[sup -1] for 1 kGy, which is 3.7 [approx] 7.4 times greater than the background. If 3 kGy is used to eliminate Salmonella, the quantity of peroxides in pork will be 1.3 x10[sup -3]mol.kg[sup -1], which approaches 24 times greater than the average value of background. When minced meat was irradiated in the presence of air, a chain reaction took place with G value 30.2. Radiation processing dose of braised chicken for shelf-life extension is [approx] 9kGy, organic peroxide content in braised chicken fat is 32.5 x10[sup -4]mol.kg[sup -1], which is about 14.7 times greater than average value (2.2x10[sup -4]mol.kg[sup -1]) in unirradiated one. Applying the peroxide method to qualitatively detect irradiated food containing fat is satisfactory, if combined with measuring the ESR signal of irradiated bone which will improve the detection method. (author).

  4. 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

  5. The protective effect of Aloysia triphylla aqueous extracts against brain lipid-peroxidation.

    Science.gov (United States)

    Lasagni Vitar, Romina M; Reides, Claudia G; Ferreira, Sandra M; Llesuy, Susana F

    2014-03-01

    In a normal diet, the use of herbs may contribute significantly to the total intake of plant antioxidants and even be a better source of dietary antioxidants than many other food groups. Therefore, the aims of this study were to evaluate the protective effect of aqueous extracts of Aloysia triphylla (infusion and decoction) against lipid-peroxidation of brain homogenates and to determine changes in the prooxidant/antioxidant balance when the plant material is added. In order to elucidate a possible antioxidant mechanism in vitro evaluation of total antioxidant capacity, oxygen species scavenging ability and reducing power (RP) were studied. Tested extracts had shown a strong inhibition of lipid-peroxidation measured as thiobarbituric acid-reactive products of lipid-peroxidation (TBARS) and chemiluminescence. Furthermore, infusion and decoction exhibited free radical trapping ability, expressed by the capacity to scavenge superoxide and hydrogen peroxide. Additionally, both aqueous extracts presented antioxidant activity measured as total reactive antioxidant potential (TRAP), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid radical (ABTS) scavenging activity and RP. These results suggest that the lipid-peroxidation inhibition mechanism proposed is that the antioxidants present in Aloysia triphylla could act as strong scavengers of reactive oxygen species not only at the initiation of the lipid-peroxidation chain reaction, but also at the propagation step. Therefore, they could be used as prophylactic and therapeutic agents for those diseases where the occurrence of oxidative stress and lipid-peroxidation contributes to the progression of damage. PMID:24477466

  6. 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

  7. Observation of atmospheric peroxides during Wangdu Campaign 2014 at a rural site in the North China Plain

    Science.gov (United States)

    Wang, Yin; Chen, Zhongming; Wu, Qinqin; Liang, Hao; Huang, Liubin; Li, Huan; Lu, Keding; Wu, Yusheng; Dong, Huabin; Zeng, Limin; Zhang, Yuanhang

    2016-09-01

    Measurements of atmospheric peroxides were made during Wangdu Campaign 2014 at Wangdu, a rural site in the North China Plain (NCP) in summer 2014. The predominant peroxides were detected to be hydrogen peroxide (H2O2), methyl hydroperoxide (MHP) and peroxyacetic acid (PAA). The observed H2O2 reached up to 11.3 ppbv, which was the highest value compared with previous observations in China at summer time. A box model simulation based on the Master Chemical Mechanism and constrained by the simultaneous observations of physical parameters and chemical species was performed to explore the chemical budget of atmospheric peroxides. Photochemical oxidation of alkenes was found to be the major secondary formation pathway of atmospheric peroxides, while contributions from alkanes and aromatics were of minor importance. The comparison of modeled and measured peroxide concentrations revealed an underestimation during biomass burning events and an overestimation on haze days, which were ascribed to the direct production of peroxides from biomass burning and the heterogeneous uptake of peroxides by aerosols, respectively. The strengths of the primary emissions from biomass burning were on the same order of the known secondary production rates of atmospheric peroxides during the biomass burning events. The heterogeneous process on aerosol particles was suggested to be the predominant sink for atmospheric peroxides. The atmospheric lifetime of peroxides on haze days in summer in the NCP was about 2-3 h, which is in good agreement with the laboratory studies. Further comprehensive investigations are necessary to better understand the impact of biomass burning and heterogeneous uptake on the concentration of peroxides in the atmosphere.

  8. Spiro-oxindole derivative 5-chloro-4',5'-diphenyl-3'-(4-(2-(piperidin-1-yl) ethoxy) benzoyl) spiro[indoline-3,2'-pyrrolidin]-2-one triggers apoptosis in breast cancer cells via restoration of p53 function.

    Science.gov (United States)

    Saxena, Ruchi; Gupta, Garima; Manohar, Murli; Debnath, Utsab; Popli, Pooja; Prabhakar, Yenamandra S; Konwar, Rituraj; Kumar, Sandeep; Kumar, Atul; Dwivedi, Anila

    2016-01-01

    Breast cancer remains a significant health problem due to the involvement of multiple aberrant and redundant signaling pathways in tumorigenesis and the development of resistance to the existing therapeutic agents. Therefore, the search for novel chemotherapeutic agents for effective management of breast cancer is still warranted. In an effort to develop new anti-breast cancer agents, we have synthesized and identified novel spiro-oxindole derivative G613 i.e. 5-chloro-4',5'-diphenyl-3'-(4-(2-(piperidin-1-yl) ethoxy) benzoyl) spiro[indoline-3,2'-pyrrolidin]-2-one, which has shown growth inhibitory activity in breast cancer cells. The present study was aimed to explore the mechanism of anti-tumorigenic action of this newly identified spiro-oxindole compound. Compound G613 inhibited the Mdm2-p53 interaction in breast cancer cells and tumor xenograft. It caused restoration of p53 function by activating its promoter activity, triggering its nuclear accumulation and preventing its ubiquitination and proteasomal degradation. Supportively, molecular docking studies revealed considerable homology in the docking mode of G613 and the known Mdm2 inhibitor Nutlin-3, to p53 binding pocket of Mdm2. The activation of p53 led to upregulation of p53 dependent pro-apoptotic proteins, Bax, Pumaα and Noxa and enhanced interaction of p53 with bcl2 member proteins thus triggering both transcription-dependent and transcription-independent apoptosis, respectively. Additionally, the compound decreased estrogen receptor activity through sequestration of estrogen receptor α by p53 thereby causing a decreased transcriptional activation and expression of proliferation markers. In conclusion, G613 represents a potent small-molecule inhibitor of the Mdm2-p53 interaction and can serve as a promising lead for developing a new class of anti-cancer therapy for breast cancer patients.

  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. Hydrogen Peroxide and Polyamines Act as Double Edged Swords in Plant Abiotic Stress Responses.

    Science.gov (United States)

    Gupta, Kamala; Sengupta, Atreyee; Chakraborty, Mayukh; Gupta, Bhaskar

    2016-01-01

    The specific genetic changes through which plants adapt to the multitude of environmental stresses are possible because of the molecular regulations in the system. These intricate regulatory mechanisms once unveiled will surely raise interesting questions. Polyamines and hydrogen peroxide have been suggested to be important signaling molecules during biotic and abiotic stresses. Hydrogen peroxide plays a versatile role from orchestrating physiological processes to stress response. It helps to achieve acclimatization and tolerance to stress by coordinating intra-cellular and systemic signaling systems. Polyamines, on the other hand, are low molecular weight polycationic aliphatic amines, which have been implicated in various stress responses. It is quite interesting to note that both hydrogen peroxide and polyamines have a fine line of inter-relation between them since the catabolic pathways of the latter releases hydrogen peroxide. In this review we have tried to illustrate the roles and their multifaceted functions of these two important signaling molecules based on current literature. This review also highlights the fact that over accumulation of hydrogen peroxide and polyamines can be detrimental for plant cells leading to toxicity and pre-mature cell death. PMID:27672389

  11. Preparation of Barium Titanate Nanopowder through Thermal Decomposition of Peroxide Precursor and Its Formation Mechanism

    Institute of Scientific and Technical Information of China (English)

    PENG, Yangxi; CHEN, Qiyuan; LIU, Shijun

    2009-01-01

    H_2TiO_3 was dissolved in the mixture of hydrogen formed peroxide and ammonia under the pH range of 8-10 with a transparent yellow solution formed. When an equivalent mole of Ba~(2+) solution was added into the yellow solution, the precipitate produced was the peroxide precursor of barium titanate. The cubic nanopowder of barium titanate was obtained when the precipitate was washed, stoved, and then calcined at 600 ℃ for 1 h. The peroxide precursor of barium titanate and barium titanate nanopowder prepared were characterized to be BaTi(H_2O_2)_2O_3 by TGA-DTA, XRD, TEM, SEM, and XREDS. The peroxide precursor of barium titanate was determined to be BaTi(H_2O_2)_2O_3. The particle size of the barium titanate nanopowder, the calcined product of BaTi(H_2O_2)_2O_3, was in the range of 20-40 nm. A formation mechanism of the barium titanate nanopowder through thermal decomposition of its peroxide precursor was proposed and then validated.

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

    Science.gov (United States)

    Semsang, Nuananong; Yu, LiangDeng

    2013-07-01

    Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

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

    Energy Technology Data Exchange (ETDEWEB)

    Prana, Vinca [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Rotureau, Patricia, E-mail: patricia.rotureau@ineris.fr [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Fayet, Guillaume [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); André, David; Hub, Serge [ARKEMA, rue Henri Moissan, BP63, Pierre Benite 69493 (France); Vicot, Patricia [Institut National de l’Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP2, Verneuil-en-Halatte 60550 (France); Rao, Li [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Adamo, Carlo [Institut de Recherche de Chimie Paris, Chimie ParisTech CNRS, 11 rue P. et M. Curie, Paris 75005 (France); Institut Universitaire de France, 103 Boulevard Saint Michel, Paris F-75005 (France)

    2014-07-15

    Highlights: • QSPR models were developed for thermal stability of organic peroxides. • Two accurate MLR models were exhibited based on quantum chemical descriptors. • Performances were evaluated by a series of internal and external validations. • The new QSPR models satisfied all OCDE principles of validation for regulatory use. - Abstract: Organic peroxides are unstable chemicals which can easily decompose and may lead to explosion. Such a process can be characterized by physico-chemical parameters such as heat and temperature of decomposition, whose determination is crucial to manage related hazards. These thermal stability properties are also required within many regulatory frameworks related to chemicals in order to assess their hazardous properties. In this work, new quantitative structure–property relationships (QSPR) models were developed to predict accurately the thermal stability of organic peroxides from their molecular structure respecting the OECD guidelines for regulatory acceptability of QSPRs. Based on the acquisition of 38 reference experimental data using DSC (differential scanning calorimetry) apparatus in homogenous experimental conditions, multi-linear models were derived for the prediction of the decomposition heat and the onset temperature using different types of molecular descriptors. Models were tested by internal and external validation tests and their applicability domains were defined and analyzed. Being rigorously validated, they presented the best performances in terms of fitting, robustness and predictive power and the descriptors used in these models were linked to the peroxide bond whose breaking represents the main decomposition mechanism of organic peroxides.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Role of mitochondrial dysfunction in hydrogen peroxide-induced apoptosis of intestinal epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Jian-Ming Li; Hong Zhou; Qian Cai; Guang-Xia Xiao

    2003-01-01

    AIM: To study the role of mitochondrial dysfunction in hydrogen peroxide-induced apoptosis of intestinal epithelial cells.METHODS: Hydrogen peroxide-induced apoptosis of human intestinal epithelial cell line SW-480 was established. Cell apoptosis was determined by Annexin-V and PI doublestained flow cytometry and DNA gel electrophoresis.Morphological changes were examined with light and electron microscopy. For other observations, mitochondrial function,cytochrome c release, mitochondrial translocation and membrane potential were determined simultaneously.RESULTS: Percentage of apoptotic cells induced with 400μ mol/L hydrogen peroxide increased significantly at I h or 3h after stimulation and recovered rapidly. Meanwhile percentage of apoptotic cells induced with 4 mmol/L hydrogen peroxide increased with time. In accordance with these changes, we observed decreased mitochondrial function in 400 μmol/L H2O2-stimualted cells at 1 h or 3 h and in 4 mmol/L H2O2-stimualted cells at times examined.Correspondingly, swelling cristae and vacuole-like mitochondria were noted. Release of cytochrome c,decreased mitochondrial membrane potential and mitochondrial translocation were also found to be the early signs of apoptosis.CONCLUSION: Dysfunctional mitochondria play a role in the apoptosis of SW-480 cell line induced by hydrogen peroxide.

  20. 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

  1. 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

  2. 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.

  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. Ferrous ion-EDTA-stimulated phospholipid peroxidation. A reaction changing from alkoxyl-radical- to hydroxyl-radical-dependent initiation.

    Science.gov (United States)

    Gutteridge, J M

    1984-01-01

    The stimulatory effect of ferrous salts on the peroxidation of phospholipids can be enhanced by EDTA when the concentration of Fe2+ in the reaction is greater than that of EDTA. Hydroxyl-radical scavengers do not inhibit peroxidation until the concentrations of Fe2+ and EDTA in the reaction are equal. Lipid peroxidation is then substantially initiated by hydroxyl radicals derived from a Fenton-type reaction requiring hydrogen peroxide. Superoxide radicals appear to play some role in the formation of initiating species. PMID:6441569

  5. Oxygen-18 study of SO/sub 2/ oxidation in rainwater by peroxides. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Holt, B.D.; Kumar, R.

    1986-07-01

    A new analytical method was developed for the determination of oxygen isotope ratios in peroxides in rainwater. In the method, rainwater samples were quantitatively degassed of dissolved air by a combined treatment of evacuation, ultrasonic agitation, and helium sparging (VUS), followed by a permanganate oxidation of the dissolved peroxide to O/sub 2/. The O/sub 2/ was then quantitatively removed from the rainwater by the VUS treatment and converted to CO/sub 2/ for mass spectrometric analysis. Using the method, 14 rainwater samples collected at four sites were analyzed to determine the fraction of the sulfate in the samples that was produced as a result of the aqueous-phase reaction of dissolved SO/sub 2/ with hydrogen peroxide.

  6. 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.

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

    Science.gov (United States)

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

    2015-05-01

    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 added to meat patties prior to cooking. The addition of black pepper to turmeric significantly decreased the lipid peroxidation in hamburger meat. When investigating the antioxidant activity of the main chemical markers, we determined that piperine did not exhibit any antioxidant activity. Therefore, we conclude that other black pepper ingredients are responsible for the increased antioxidant activity of combining black pepper with turmeric powder.

  8. 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

  9. Additive effect of alcohol and nicotine on lipid peroxidation and antioxidant defence mechanism in rats.

    Science.gov (United States)

    Ashakumary, L; Vijayammal, P L

    1996-01-01

    Cigarette smoking has been established as a major risk factor for atherosclerosis and also for lung cancer. Nicotine is one of the major toxic components of cigarette smoke that is believed to be partly responsible for the deleterious effect of cigarette smoke. Alcohol intake is another major risk factor for the development of cardiovascular disease. Lipid peroxidation is a process associated with the pathogenesis of atherosclerosis. The concentration of lipid peroxides is found to be increased in alcohol-treated rats. On nicotine administration along with alcohol, an additive effect was observed in lipid peroxidation and the antioxidant defence mechanism. The activity of scavenging enzymes superoxide dismutase, catalase and glutathione reductase was found to be decreased, while the activity of glutathione peroxidase and the concentration of glutathione were increased. PMID:8854216

  10. 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

  11. Assessment of redox changes to hydrogen peroxide-sensitive proteins during EGF signaling.

    Science.gov (United States)

    Cuddihy, Sarah L; Winterbourn, Christine C; Hampton, Mark B

    2011-07-01

    Hydrogen peroxide acts as a second messenger in growth factor signaling where it can oxidize and modify the function of redox-sensitive proteins. While selective thiol oxidation has been measured, there has been no global assessment of protein oxidation following growth factor activation. Significant changes to the abundant and widely distributed redox sensitive thiol proteins were observed in A431 epidermoid carcinoma cells exposed to hydrogen peroxide, but no changes were observed following treatment with epidermal growth factor (EGF). This included members of the peroxiredoxin family, which were also monitored in the presence of the thioredoxin reductase inhibitor auranofin to limit their capacity to recycle to the reduced form. We conclude that widespread thiol oxidation does not occur in cells during EGF signaling, and that hydrogen peroxide must act in a highly localized or selective manner.

  12. [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

  13. 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.

  14. 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

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

    Directory of Open Access Journals (Sweden)

    L. I. Ratnikova

    2011-01-01

    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.

  16. DISY. The direct synthesis of hydrogen peroxide, a bridge for innovative applications

    Energy Technology Data Exchange (ETDEWEB)

    Buzzoni, R.; Perego, C. [Eni S.p.A., Novara (Italy). Research Center for Non-Conventional Energies

    2011-07-01

    Hydrogen peroxide is largely recognized as the green oxidant of choice for future sustainable processes. The current industrial production still goes through the old anthraquinone process, a complex, two-step process suffering from a low specific productivity. Following the development of TS-1/H{sub 2}O{sub 2} based selective oxidation processes e.g. propylene epoxidation, cyclohexanone ammoximation and the new benzene direct oxidation to phenol, there has been an incentive for the development of a new technology, simpler and with better economics. DISY process, based on direct synthesis of hydrogen peroxide from hydrogen and oxygen, is highly suitable to the design of integrated selective oxidation processes as well as for production of commercial-grade high concentration aqueous hydrogen peroxide solutions. Catalyst and process development up to pilot scale are described. (orig.)

  17. Protective effect of Apocynum venetum (罗布麻) against lipid peroxidation damage of erythrocyte membrane

    Institute of Scientific and Technical Information of China (English)

    Zhou Benhong; Liu Gang; Hu Xianmin

    2004-01-01

    Objective: To investigate the protective effect of Apocynum venetum on lipid peroxidation damage of erythrocyte membrane. Methods: Model of lipid peroxidation of erythrocyte membrane was manufactured by three kinds of radicals generation systems. To set up a normal control group (NC), a model control group (MC), and four Apocynum venetum groups(A.V). Observation was made on the content of malondialdehyde (MDA). Results: Compared with MC group, all of the four Apocynum venetum groups dose-dependently inhibited the increases of MDA content in the membrane induced by xanthine - xanthine oxidase system, H2O2 or UV light. Conclusions: Apocynum venetum may protect erythrocyte membrane from the lipid peroxidative damage induced by radicals.

  18. 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.

  19. 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.

  20. 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.