Sample records for benzoyl peroxide

  1. Benzoyl Peroxide Topical

    MedlinePlus

    ... the benzoyl peroxide product to one or two small areas you want to treat for 3 days when ... cream, or gel, first wash the affected skin areas and gently pat dry with a towel. Then apply a small amount of benzoyl Peroxide, rub it in gently. ...

  2. Comparative trial of benzoyl peroxide versus benzoyl peroxide with urea in inflammatory acne.

    PubMed

    Prince, R A; Harris, J M; Maroc, J A

    1982-06-01

    Improvement in vehicle design may improve the delivery of drugs to the target site. A clinical trial was performed to evaluate an improved vehicle for topical benzoyl peroxide. Thirty-nine subjects participated in a split-face, double-blind trial of topical benzoyl peroxide 5 percent versus benzoyl peroxide 5 percent in 8 percent urea. All subjects had grade II or III acne as described by Pillsbury. Study solutions were randomly assigned to a selected side of the subject's face and applied twice a day to the appropriate side of the face for eight weeks. Total and inflammatory lesion counts were performed by the same investigator during the eight weeks of study at biweekly intervals. No overall differences in the response to the study preparations were observed when assessed objectively and subjectively.

  3. The Tolerability Profile of Clindamycin 1%/Benzoyl Peroxide 5% Gel vs. Adapalene 0.1%/Benzoyl Peroxide 2.5% Gel for Facial Acne

    PubMed Central

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

    2012-01-01

    Objective: To compare the first two weeks of tolerability of clindamycin/benzoyl peroxide gel versus adapalene/benzoyl peroxide gel followed by six weeks of open-label clindamycin/benzoyl peroxide gel therapy in subjects with mild-to-moderate acne who participated in two eight-week, identically designed, clinical studies. Methods: Using a split-face method, patients received both clindamycin/benzoyl peroxide gel and adapalene/benzoyl peroxide gel once daily for two weeks (allocation to the right or left side of the face was randomized) in an investigator-blinded fashion. Patients then went on to receive a further six weeks of open-label, full-face clindamycin/benzoyl peroxide gel. The primary outcome was to compare signs and symptoms of tolerability during the first two weeks of treatment using an investigator-assessed 4-point rating scale. Secondary endpoints included assessment of acne severity (Investigator Static Global Assessment and lesion counts), quality of life, product acceptability/preference, and patient assessments of tolerability and safety. Results: Of the 76 subjects enrolled in the two studies, 72 completed them. Overall both products were well tolerated, but mean scores for erythema, dryness, and peeling were significantly higher with adapalene/benzoyl peroxide gel than with clindamycin/benzoyl peroxide gel at both Weeks 1 and 2 (p<0.03). Patients also rated clindamycin/benzoyl peroxide gel significantly more tolerable than adapalene/benzoyl peroxide gel for redness, dryness, burning, itching, and scaling at Weeks 1 and 2 (p 0.0073). Mean Investigator Static Global Assessment score improved with both products during the first two weeks of treatment and continued to show significant improvement versus baseline when treatment with clindamycin/benzoyl peroxide gel was continued for a further six weeks (p<0.001 at Week 8). Lesion counts improved throughout the study with significant reductions from baseline occurring at Weeks 5 and 8 (p<0.0001 for

  4. A Three-Step Synthesis of Benzoyl Peroxide

    ERIC Educational Resources Information Center

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

    2014-01-01

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

  5. A 6% Benzoyl Peroxide Foaming Cloth Cleanser Used in the Treatment of Acne Vulgaris

    PubMed Central

    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 vulgaris were enrolled. Measures: Subjects initially cleansed their face with the benzoyl peroxide foaming cloth and then completed a product-attribute survey. Following an interval of five minutes or more, subjects cleansed their face again using one of two randomly assigned comparator benzoyl peroxide-containing cleansing products and then completed a comparative survey. Survey results were tabulated and a top-two box analysis was performed. Results: Following the use of the benzoyl peroxide-containing foaming cloth, 94 percent of the product-attribute responses were positive (p≤0.05). With respect to convenience, usability, and cosmetic elegance, the majority of subjects indicated a preference for the benzoyl peroxide foaming cloth compared to the 6% benzoyl peroxide cleanser and 4% benzoyl peroxide wash (for each, p≤0.05). There were no reports of adverse events. Conclusion: These attributes supporting preference for the benzoyl peroxide foaming cloth cleanser may improve patient satisfaction with topical acne treatment resulting in improved patient compliance. (J Clin Aesthetic Dermatol. 2009;2(7):26–29.) PMID:20729967

  6. Hydrogen peroxide as a new defensive compound in "benzoyl cyanide" producing polydesmid millipedes

    NASA Astrophysics Data System (ADS)

    Kuwahara, Yasumasa; Yamaguchi, Takuya; Ichiki, Yayoi; Tanabe, Tsutomu; Asano, Yasuhisa

    2017-04-01

    Hydrogen peroxide was newly and simultaneously demonstrated with well-known hydrogen cyanide as a component of defensive secretions of "benzoyl cyanide" producing polydesmid millipedes. Presence of hydrogen peroxide was successively evidenced by Trinder reagent's spray with colorless as well as oily smears of defensive secretions containing benzoyl cyanide and hydrogen cyanide by alkaline picrate paper treatment. Linear correlation was demonstrated between quantities of hydrogen peroxide and benzoyl cyanide. By qualitative assay, seven benzoyl cyanide containing polydesmidans (six species of adults and one species of a nymph at stadium I) tested positive to Trinder reagent, indicative of the presence of hydrogen peroxide (together with hydrogen cyanide), while two cyanogenic species without benzoyl cyanide exhibited negative responses to the reagent. Two types of millipedes were elucidated as species of cyanogenic Polydesmida.

  7. Hydrogen peroxide as a new defensive compound in "benzoyl cyanide" producing polydesmid millipedes.

    PubMed

    Kuwahara, Yasumasa; Yamaguchi, Takuya; Ichiki, Yayoi; Tanabe, Tsutomu; Asano, Yasuhisa

    2017-04-01

    Hydrogen peroxide was newly and simultaneously demonstrated with well-known hydrogen cyanide as a component of defensive secretions of "benzoyl cyanide" producing polydesmid millipedes. Presence of hydrogen peroxide was successively evidenced by Trinder reagent's spray with colorless as well as oily smears of defensive secretions containing benzoyl cyanide and hydrogen cyanide by alkaline picrate paper treatment. Linear correlation was demonstrated between quantities of hydrogen peroxide and benzoyl cyanide. By qualitative assay, seven benzoyl cyanide containing polydesmidans (six species of adults and one species of a nymph at stadium I) tested positive to Trinder reagent, indicative of the presence of hydrogen peroxide (together with hydrogen cyanide), while two cyanogenic species without benzoyl cyanide exhibited negative responses to the reagent. Two types of millipedes were elucidated as species of cyanogenic Polydesmida.

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

    NASA Astrophysics Data System (ADS)

    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

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

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  10. Absence of Degradation of Tretinoin When Benzoyl Peroxide is Combined with an Optimized Formulation of Tretinoin Gel (0.05%)

    PubMed Central

    Pillai, Radhakrishnan; Moore, Robert

    2010-01-01

    Background: Clinicians have been reluctant to prescribe benzoyl peroxide concurrently with topical tretinoin due to a belief that the benzoyl peroxide may cause oxidation and degradation of the tretinoin molecule, thereby reducing its effectiveness. However, benzoyl peroxide-induced degradation of tretinoin may not necessarily apply to all topical tretinoin formulations. Objective: To evaluate the potential for benzoyl peroxide-induced degradation of an optimized aqueous gel formulation of tretinoin (0.05%). Methods: Tretinoin gel (0.05%) and benzoyl peroxide gel (6.26% premix concentration to produce 5% benzoyl peroxide in a fixed combination clindamycin product) were mixed together (1:1) at 32ºC and samples assayed after 1, 2, 3, 5, and 7 hours. Each sample was analyzed for tretinoin (expressed as % tretinoin remaining) and its degradation product content. Results: No loss of tretinoin was observed over the seven-hour time period. When tretinoin gel (0.05%) was combined with benzoyl peroxide, 100 percent of the initial tretinoin concentration remained after seven hours. There was no increase in the degradation products of tretinoin. Conclusions: There was no benzoyl peroxide-induced degradation of tretinoin when the optimized formulation of tretinoin gel (0.05%) was admixed with benzoyl peroxide gel (6.26%). Although the direct clinical significance of these results is unknown, clinicians may feel comfortable using this particular combination concurrently without concerns about tretinoin oxidation and degradation. PMID:20967192

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

    PubMed Central

    Nguyen, Tuyet A; Eichenfield, Lawrence F

    2015-01-01

    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. PMID:26604811

  12. 75 FR 9767 - Classification of Benzoyl Peroxide as Safe and Effective and Revision of Labeling to Drug Facts...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... photocarcinogenicity studies at that time. We also proposed labeling to communicate the results of the animal studies... promoter, benzoyl peroxide, at multiple times throughout the remainder of the study. Because tumor... to the backs 5 times per week for 50 weeks. In this study, benzoyl peroxide was not a tumor promoter...

  13. Sensory and Functionality Differences of Whey Protein Isolate Bleached by Hydrogen or Benzoyl Peroxide.

    PubMed

    Smith, Tucker J; Foegeding, E Allen; Drake, MaryAnne

    2015-10-01

    Whey protein is a highly functional food ingredient used in a wide variety of applications. A large portion of fluid whey produced in the United States is derived from Cheddar cheese manufacture and contains annatto (norbixin), and therefore must be bleached. The objective of this study was to compare sensory and functionality differences between whey protein isolate (WPI) bleached by benzoyl peroxide (BP) or hydrogen peroxide (HP). HP and BP bleached WPI and unbleached controls were manufactured in triplicate. Descriptive sensory analysis and gas chromatography-mass spectrometry were conducted to determine flavor differences between treatments. Functionality differences were evaluated by measurement of foam stability, protein solubility, SDS-PAGE, and effect of NaCl concentration on gelation relative to an unbleached control. HP bleached WPI had higher concentrations of lipid oxidation and sulfur containing volatile compounds than both BP and unbleached WPI (P < 0.05). HP bleached WPI was characterized by high aroma intensity, cardboard, cabbage, and fatty flavors, while BP bleached WPI was differentiated by low bitter taste. Overrun and yield stress were not different among WPI (P < 0.05). Soluble protein loss at pH 4.6 of WPI decreased by bleaching with either hydrogen peroxide or benzoyl peroxide (P < 0.05), and the heat stability of WPI was also distinct among WPI (P < 0.05). SDS PAGE results suggested that bleaching of whey with either BP or HP resulted in protein degradation, which likely contributed to functionality differences. These results demonstrate that bleaching has flavor effects as well as effects on many of the functionality characteristics of whey proteins. Whey protein isolate (WPI) is often used for its functional properties, but the effect of oxidative bleaching chemicals on the functional properties of WPI is not known. This study identifies the effects of hydrogen peroxide and benzoyl peroxide on functional and flavor characteristics of WPI

  14. Formulation and Characterization of Benzoyl Peroxide Gellified Emulsions

    PubMed Central

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

    2012-01-01

    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. PMID:23264949

  15. Results of a Multicenter, Randomized, Controlled Trial of a Hydrogen Peroxide-based Kit versus a Benzoyl Peroxide-based Kit in Mild-to-moderate Acne

    PubMed Central

    Micali, Giuseppe; Berardesca, Enzo; Dall’Oglio, Federica; Sinagra, Jo Linda; Guanziroli, Elena

    2016-01-01

    Objective:To evaluate the efficacy and tolerability of a novel hydrogen peroxide-based regimen versus a benzoyl peroxide-based regimen in mild-to-moderate acne. Methods: In this eight-week multicenter study, patients were randomized to either a hydrogen peroxide-based or a benzoyl peroxide-based regimen.The primary outcome measure of clinical response was assessed using the Global Acne Grading System (GAGS) at baseline,four weeks, and eight weeks. At Week 8, a patient self-satisfaction questionnaire was administered. Investigators were also queried at that time regarding assessment of tolerability and cosmetic acceptability. Tolerability was also measured at each visit. Results: Both treatment regimens were associated with improvement of GAGS score at Week 8 compared to baseline (p<0.0001). GAGS score did not differ significantly between the two regimens over the same period (p=0.7765). No significant adverse events were reported or observed in either treatment arm. Both patients and investigators found both regimens to be similarly effective and cosmetically acceptable. Conclusion: A novel hydrogen peroxide-based regimen was shown to be comparable in efficacy, safety, and cosmetic acceptability to a benzoyl peroxide-based regimen in the treatment of mild-to-moderate acne. PMID:27847549

  16. Evaluating clinical trial design: systematic review of randomized vehicle-controlled trials for determining efficacy of benzoyl peroxide topical therapy for acne.

    PubMed

    Lamel, Sonia A; Sivamani, Raja K; Rahvar, Maral; Maibach, Howard I

    2015-11-01

    Determined efficacies of benzoyl peroxide may be affected by study design, implementation, and vehicle effects. We sought to elucidate areas that may allow improvement in determining accurate treatment efficacies by determining rates of active treatment and vehicle responders in randomized controlled trials assessing the efficacy of topical benzoyl peroxide to treat acne. We conducted a systematic review of randomized vehicle-controlled trials evaluating the efficacy of topical benzoyl peroxide for the treatment of acne. We compared response rates of vehicle treatment arms versus those in benzoyl peroxide arms. Twelve trials met inclusion criteria with 2818 patients receiving benzoyl peroxide monotherapy treatment and 2004 receiving vehicle treatment. The average percent reduction in total number of acne lesions was 44.3 (SD = 9.2) and 27.8 (SD = 21.0) for the active and vehicle treatment groups, respectively. The average reduction in non-inflammatory lesions was 41.5 % (SD = 9.4) in the active treatment group and 27.0 % (SD = 20.9) in the vehicle group. The average percent decrease in inflammatory lesions was 52.1 (SD = 10.4) in the benzoyl peroxide group and 34.7 (SD = 22.7) in the vehicle group. The average percentage of participants achieving success per designated study outcomes was 28.6 (SD = 17.3) and 15.2 (SD = 9.5) in the active treatment and vehicle groups, respectively. Patient responses in randomized controlled trials evaluating topical acne therapies may be affected by clinical trial design, implementation, the biologic effects of vehicles, and natural disease progression. "No treatment" groups may facilitate determination of accurate treatment efficacies.

  17. Phototoxic effects of topical azelaic acid, benzoyl peroxide and adapalene were not detected when applied immediately before UVB to normal skin.

    PubMed

    Cetiner, Salih; Ilknur, Turna; Ozkan, Sebnem

    2004-01-01

    The enhancing effects on UVB erythema of topical agents applied on sun exposed areas are important due to their increased sunburn risk. Since the lesions in acne vulgaris are seen primarily on the face, the effects of topical agents used in acne treatment on the erythemogenicity of UVB is important. The aim of the present study was to examine whether azelaic acid cream, benzoyl peroxide gel, adapalene gel have the enhancing effects on UVB erythema which are widely used in the topical treatment of acne vulgaris. The minimal erythema dose (MED) was determined with phototest in 30 volunteers and the test was repeated with thin (0.1 cc/25 cm(2)) and thick (0.3 cc/25 cm(2)) azelaic acid cream, benzoyl peroxide gel, adapalene gel. The effects of each agent on MED was determined after 24 hours. MEDs of UVB were unaffected by azelaic acid cream, benzoyl peroxide gel and adapalene gel when applied immediately before irradiation. According to our results azelaic acid, benzoyl peroxide and adapalene do not seem to have enhancing effects on UVB erythema and thus increased sunburn risk.

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

    PubMed

    Bhatia, Neal; Pillai, Radhakrishnan

    2015-09-01

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

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

    PubMed Central

    Pillai, Radhakrishnan

    2015-01-01

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

  20. Quantitative detection of benzoyl peroxide in wheat flour by line-scan macro-scale Raman chemical imaging

    USDA-ARS?s Scientific Manuscript database

    A high-throughput Raman chemical imaging method was developed for direct inspection of benzoyl peroxide (BPO) mixed in wheat flour. A 5 W 785 nm line laser (240 mm long and 1 mm wide) was used as a Raman excitation source in a push-broom Raman imaging system. Hyperspectral Raman images were collecte...

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

    PubMed Central

    Korotzer, Andrew

    2015-01-01

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

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

    PubMed

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

    2011-09-03

    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.

  3. [Acne therapy with topical benzoyl peroxide, antibiotics and azelaic acid].

    PubMed

    Worret, Wolf-Ingo; Fluhr, Joachim W

    2006-04-01

    Benzoyl peroxide (BPO) was introduced in the treatment of acne in 1934. Despite the fact that only few randomized trials have been published, BPO is considered the standard in topical acne treatment. Anaerobic bacteria are reduced by oxidative mechanisms and the induction of resistant strains is reduced. Topical formulations are available at concentrations of 2.5, 5, 10 and 20 %. The effect is dose-dependent, but the irritation increases with higher concentrations. Usually 5 % BPO is sufficient to control acne grade I-II. Due to its strong oxidative potential, patients should be advised that BPO may bleach colored and dark clothing, bedding and even hair. BPO is safe for use in pregnant and lactating females because it is degraded to benzoic acid. It is a cost-effective treatment for acne grade I-II. Patients with papulopustular acne grade I-II, particularly with marked inflammation, show satisfactory improvement with topical antibiotic treatment. The following compounds are available and effective: erythromycin, clindamycin and tetracycline (the latter being less frequently used). A review in 1990 suggested that topical tetracycline was ineffective in the treatment of acne. Along with eliminating Propionibacterium acnes, the main mechanism of topical antibiotics is their antiinflammatory effect. All three penetrate the epidermal barrier well and are similarly efficacious. Randomized trials have shown that in concentrations of 2-4 %, their effects are comparable to oral tetracycline and minocycline. Combination therapy with retinoids or benzoyl peroxide (BPO) increases efficacy. Retinoids increase penetration and reduce comedones, while topical antibiotics primarily address inflammation. One side effect of topical antibacterial treatment is an increase in drug-resistant resident skin flora with gram-negative microorganisms prevailing, which can lead to gram-negative folliculitis. All three antibiotics fluoresce under black light which may produce interesting

  4. Benzoyl peroxide and clindamycin topical skin preparation decreases Propionibacterium acnes colonization in shoulder arthroscopy.

    PubMed

    Dizay, Hailey H; Lau, Diana G; Nottage, Wesley M

    2017-07-01

    Propionibacterium acnes is a gram-positive anaerobe that can lead to devastating postoperative shoulder infections. The objective of this study was to investigate whether a benzoyl peroxide and clindamycin preoperative skin preparation reduces the incidence of P. acnes colonization during shoulder arthroscopy. Sixty-five shoulder arthroscopy patients were prospectively enrolled. A skin culture specimen was taken at the preoperative visit from standard arthroscopic portal sites. Topical benzoyl peroxide 5% and clindamycin 1.2% (BPO/C) gel was applied to the shoulder every night before surgery. Skin culture was repeated in the operating room before preparation with chlorhexidine gluconate. Shoulder arthroscopy proceeded, with final culture specimens obtained from within the shoulder. P. acnes skin colonization remained similar to prior studies at 47.7% (31 of 65 patients.) With >1 application, BPO/C was 78.9% (15 of 19 patients) effective in eliminating P. acnes superficial colonization. With 1 application, it was 66.7% (8 of 12 patients) effective in eliminating superficial colonization. Deep colonization was reduced to 3.1% (2 of 65 patients) compared with previous studies of 15% to 20% (P = .006). BPO/C was 100% effective at decreasing deep colonization with >1 application. P. acnes skin colonization is high at arthroscopic shoulder portals, especially in men. Despite standard skin preparation and prophylactic antibiotics, the rate of joint inoculation is much higher than the rate of infection reported in the literature. BPO/C effectively reduces P. acnes colonization in shoulder arthroscopy. It should be considered for use before shoulder procedures with a time-related trend of >1 application. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

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

    PubMed

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

    2015-11-01

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

  6. Dapsone gel 5% in combination with adapalene gel 0.1%, benzoyl peroxide gel 4% or moisturizer for the treatment of acne vulgaris: a 12-week, randomized, double-blind study.

    PubMed

    Fleischer, Alan B; Shalita, Alan; Eichenfield, Lawrence F; Abramovits, William; Lucky, Anne; Garrett, Steven

    2010-01-01

    To evaluate the safety and efficacy of dapsone gel 5% in the treatment of acne when used in combination with adapalene gel 0.1%, benzoyl peroxide gel 4% or moisturizer. This was a twelve-week, randomized, double-blind study. Patients aged 12 years and older (n=301) applied dapsone gel twice daily and were randomly assigned (1:1:1) to one of three additional treatments, applied once daily. By week 12, dapsone gel combined with any of the three additional treatments reduced the mean number of inflammatory lesions. However, the authors did not detect a significant difference in the reduction of inflammatory lesions when dapsone was used in combination with adapalene gel or with benzoyl peroxide gel compared to the dapsone plus moisturizer combination group (P=0.052 for both versus moisturizer combination). Patients treated with dapsone gel combined with adapalene showed a significantly better response in reduction in non-inflammatory and total acne lesion count than those who received the moisturizer combination. Local adverse reactions in all three treatment groups were minimal and generally mild in severity. Dapsone gel in combination with adapalene gel or benzoyl peroxide gel is safe and well tolerated for the treatment of acne vulgaris.

  7. Efficacy of Intense-pulsed Light Therapy with Topical Benzoyl Peroxide 5% versus Benzoyl Peroxide 5% Alone in Mild-to-moderate Acne Vulgaris: A Randomized Controlled Trial.

    PubMed

    Mokhtari, Fatemeh; Gholami, Maryam; Siadat, Amir Hossein; Jafari-Koshki, Tohid; Faghihi, Gita; Nilforoushzadeh, Mohammad Ali; Hosseini, Sayed Mohsen; Abtahi-Naeini, Bahareh

    2017-01-01

    Acne vulgaris is a disease of pilosebaceous unit with multifactorial pathogenesis and threats patients' social functioning. There is a growing research to find faster, more effective, and easy to use treatments. The aim of this study is to evaluate the efficacy of benzoyl peroxide 5% (BP) with and without concomitant intense-pulsed light (IPL) therapy in mild-to-moderate acne vulgaris. In this controlled trial, 58 eligible patients with mild-to-moderate acne and Fitzpatrick skin phototype III and IV were randomly allocated to two groups. All patients were asked to use a thin layer of BP every night. The IPL therapy was administered at the end of first, 2 nd , and 3 rd months. Acne Global Severity Scale (AGSS), Acne Severity Index (ASI), and total lesion counting (TLC) along with patient satisfaction were recorded. Patients were also examined 1 month after the final therapeutic visit. The IPL group showed greater reduction in AGSS ( P < 0.001) and TLC ( P = 0.005) than the control group. However, the difference in ASI was not significant ( P = 0.12). Patients in IPL groups were more satisfied than control group ( P < 0.001). Adding IPL to BP can result better response to BP alone. In acne treatment, combination therapy such as IPL and other topical agents should be kept in mind.

  8. Efficacy of Intense-pulsed Light Therapy with Topical Benzoyl Peroxide 5% versus Benzoyl Peroxide 5% Alone in Mild-to-moderate Acne Vulgaris: A Randomized Controlled Trial

    PubMed Central

    Mokhtari, Fatemeh; Gholami, Maryam; Siadat, Amir Hossein; Jafari-Koshki, Tohid; Faghihi, Gita; Nilforoushzadeh, Mohammad Ali; Hosseini, Sayed Mohsen; Abtahi-Naeini, Bahareh

    2017-01-01

    Objective: Acne vulgaris is a disease of pilosebaceous unit with multifactorial pathogenesis and threats patients' social functioning. There is a growing research to find faster, more effective, and easy to use treatments. The aim of this study is to evaluate the efficacy of benzoyl peroxide 5% (BP) with and without concomitant intense-pulsed light (IPL) therapy in mild-to-moderate acne vulgaris. Methods: In this controlled trial, 58 eligible patients with mild-to-moderate acne and Fitzpatrick skin phototype III and IV were randomly allocated to two groups. All patients were asked to use a thin layer of BP every night. The IPL therapy was administered at the end of first, 2nd, and 3rd months. Acne Global Severity Scale (AGSS), Acne Severity Index (ASI), and total lesion counting (TLC) along with patient satisfaction were recorded. Patients were also examined 1 month after the final therapeutic visit. Findings: The IPL group showed greater reduction in AGSS (P < 0.001) and TLC (P = 0.005) than the control group. However, the difference in ASI was not significant (P = 0.12). Patients in IPL groups were more satisfied than control group (P < 0.001). Conclusion: Adding IPL to BP can result better response to BP alone. In acne treatment, combination therapy such as IPL and other topical agents should be kept in mind. PMID:29417078

  9. [Antibiotics, azelaic acid and benzoyl peroxide in topical acne therapy].

    PubMed

    Fluhr, Joachim W; Degitz, Klaus

    2010-03-01

    Benzoyl peroxide was introduced as a basic treatment already in acne therapy 1934. The mechanism of action is the reduction of anaerobe bacteria by strong oxidation processes. No resistancies have been ever reported. BPO is available in 2.5, 5 and 10 % formulations. Its efficacy is slightly related to the strength of concentrations, but the side effect profile with burning, erythema and desquamation is increasing with concentrations. BPO 5% mostly is efficient enough to control acne of grades I to II according to the Kligman & Plewig classification. BPO my bleach clothes and hair. It is the most costeffective topical drug in acne of grades I-II. Inflammatory acne of the papular-pustular type I-II can also be treated by topical antibiotics such as erythromycin, clindamycin, and, less frequent and today not anymore recommended tetracyclines. Mechanism of action is not alone an antibacterial but anti inflammatory effect. The efficacy and penetration of the topical antibiotics between the groups are similar. Randomized studies have shown that concentrations of 2-4% are equivalent to oral tetracycline and minocycline in mild to moderate acne. Combinatory formulations with BPO and with retinoids enhance the efficacy significantly. Topical antibiotics plus BPO show less bacterial resistancies as topical antibiotics alone. Antibiotics should therefore not be used as monotherapy. Moreover gram negative folliculitis may develop. Azelaic acid is acting as an antimicrobial and can also reduce comedones. It can also be used in pregnancy and during the lactation period.

  10. Detecting benzoyl peroxide in wheat flour by line-scan macro-scale Raman chemical imaging

    NASA Astrophysics Data System (ADS)

    Qin, Jianwei; Kim, Moon S.; Chao, Kuanglin; Gonzalez, Maria; Cho, Byoung-Kwan

    2017-05-01

    Excessive use of benzoyl peroxide (BPO, a bleaching agent) in wheat flour can destroy flour nutrients and cause diseases to consumers. A macro-scale Raman chemical imaging method was developed for direct detection of BPO mixed in the wheat flour. A 785 nm line laser was used in a line-scan Hyperspectral Raman imaging system. Raman images were collected from wheat flour mixed with BPO at eight concentrations (w/w) from 50 to 6,400 ppm. A sample holder (150×100×2 mm3) was used to present a thin layer (2 mm thick) of the powdered sample for image acquisition. A baseline correction method was used to correct the fluctuating fluorescence signals from the wheat flour. To isolate BPO particles from the flour background, a simple thresholding method was applied to the single-band fluorescence-free images at a unique Raman peak wavenumber (i.e., 1001 cm-1) preselected for the BPO detection. Chemical images were created to detect and map the BPO particles. Limit of detection for the BPO was estimated in the order of 50 ppm, which is on the same level with regulatory standards.

  11. A skincare combined with combination of adapalene and benzoyl peroxide provides a significant adjunctive efficacy and local tolerance benefit in adult women with mild acne.

    PubMed

    Bouloc, A; Roo, E; Imko-Walczuk, B; Moga, A; Chadoutaud, B; Dréno, B

    2017-10-01

    Acne in adult women is an increasing reason for dermatological consultations. The aim of this study was to assess in adult women with mild acne the efficacy and tolerance of a daily adjunctive application of a skincare (Normaderm ® , Laboratoires Vichy, France) to a fixed combination of adapalene/benzoyl peroxide daily or every other evening and a standard emollient. Subjects were randomized to receive the fixed combination applied either every evening or every other evening and a daily application of the standard emollient and the test care or a once daily application of the fixed combination and the standard emollient alone. Clinical evaluations at Day 0, Day 45 and Day 90 included the count of acne lesions, assessment of clinical improvement and local tolerance. The quantitative lipid profile of the stratum corneum of the forehead was also determined. After 90 days of application, acne had improved in all 299 subjects with a statistically significant difference in favour of the test care regimens (P < 0.05). Moreover, skin quality, subject satisfaction, skin discomfort and sebum composition were in favour of these regimens. In conclusion, the tested skincare combined with a fixed adapalene and benzoyl peroxide combination provides a significant adjunctive efficacy and local tolerance benefit in adult women with mild acne. © 2017 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology.

  12. Benzoyl Peroxide as an Efficient Dopant for Spiro-OMeTAD in Perovskite Solar Cells.

    PubMed

    Liu, Qiuju; Fan, Lisheng; Zhang, Qin'e; Zhou, An'an; Wang, Baozeng; Bai, Hua; Tian, Qingyong; Fan, Bin; Zhang, Tongyi

    2017-08-10

    Although organic small molecule spiro-OMeTAD is widely used as a hole-transport material in perovskite solar cells, its limited electric conductivity poses a bottleneck in the efficiency improvement of perovskite solar cells. Here, a low-cost and easy-fabrication technique is developed to enhance the conductivity and hole-extraction ability of spiro-OMeTAD by doping it with commercially available benzoyl peroxide (BPO). The experimental results show that the conductivity increases several orders of magnitude, from 6.2×10 -6  S cm -1 for the pristine spiro-OMeTAD to 1.1×10 -3  S cm -1 at 5 % BPO doping and to 2.4×10 -2  S cm -1 at 15 % BPO doping, which considerably outperform the conductivity of 4.62×10 -4  S cm -1 for the currently used oxygen-doped spiro-OMeTAD. The fluorescence spectra suggest that the BPO-doped spiro-OMeTAD-OMeTAD layer is able to efficiently extract holes from CH 3 NH 3 PbI 3 and thus greatly enhances the charge transfer. The BPO-doped spiro-OMeTAD is used in the fabrication of perovskite solar cells, which exhibit enhancement in the power conversion efficiency. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Efficacy and safety of tretinoin 0.025%/clindamycin phosphate 1.2% gel in combination with benzoyl peroxide 6% cleansing cloths for the treatment of facial acne vulgaris.

    PubMed

    Zeichner, Joshua A; Wong, Vicky; Linkner, Rita V; Haddican, Madelaine

    2013-03-01

    Combination therapy using medications with complementary mechanisms of action is the standard of care in treating acne. We report results of a clinical trial evaluating the use of a fixed-dose tretinoin 0.025%/clindamycin phosphate 1.2% (T/CP) gel in combination with a benzoyl peroxide 6% foaming cloth compared with T/CP alone for facial acne. At week 12, the combination therapy group showed a trend toward greater efficacy compared with T/CP alone. There was a high success rate observed in the study, which may be attributable to the large percentage of adult female acne patients enrolled. Cutaneous adverse events were not statistically different in using combination therapy compared with T/CP alone.

  14. N-Benzoyl-D-phenylalanine attenuates brain acetylcholinesterase in neonatal streptozotocin-diabetic rats.

    PubMed

    Ashokkumar, Natarajan; Pari, Leelavinothan; Ramkumar, Kunga Mohan

    2006-09-01

    The effect of hyperglycaemia due to experimental diabetes in male Wistar rats causes a decrease in the level of acetylcholinesterase (AChE) with significant increase in lipid peroxidative markers: thiobarbituric acid-reactive substances (TBARS) and hydroperoxides in brains of experimental animals. The decreased activity of both salt soluble and detergent soluble acetylcholinesterase observed in diabetes may be attributed to lack of insulin which causes specific alterations in the level of neurotransmitter, thus causing brain dysfunction. Administration of non-sulfonylurea drug N-benzoyl-D-phenylalanine (NBDP) could protect against direct action of lipid peroxidation on brain AChE and in this way it might be useful in the prevention of cholinergic neural dysfunction, which is one of the major complications in diabetes.

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

    PubMed

    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. © 2011 Japanese Dermatological Association.

  16. Efficacy and safety of a ceramide containing moisturizer followed by fixed-dose clindamycin phosphate 1.2%/benzoyl peroxide 2.5% gel in the morning in combination with a ceramide containing moisturizer followed by tretinoin 0.05% gel in the evening for the treatment of facial acne vulgaris.

    PubMed

    Zeichner, Joshua A; Patel, Rita V; Haddican, Madelaine; Wong, Vicky

    2012-06-01

    Combination therapy addressing multiple pathogenic factors should be used to achieve optimal outcomes in treating acne. The following study demonstrated both safety and efficacy of fixed-dose clindamycin phosphate 1.2%/benzoyl peroxide 2.5% in the morning with micronized tretinoin 0.05% gel in the evening. Both products were applied to the skin following the use of a ceramide containing moisturizing lotion.

  17. The impact of iron on the bleaching efficacy of hydrogen peroxide in liquid whey systems.

    PubMed

    Jervis, Suzanne M; Drake, MaryAnne

    2013-02-01

    Whey is a value-added product that is utilized in many food and beverage applications for its nutritional and functional properties. Whey and whey products are generally utilized in dried ingredient applications. One of the primary sources of whey is from colored Cheddar cheese manufacture that contains the pigment annatto resulting in a characteristic yellow colored Cheddar cheese. The colorant is also present in the liquid cheese whey and must be bleached so that it can be used in ingredient applications without imparting a color. Hydrogen peroxide and benzoyl peroxide are 2 commercially approved chemical bleaching agents for liquid whey. Concerns regarding bleaching efficacy, off-flavor development, and functionality changes have been previously reported for whey bleached with hydrogen peroxide and benzoyl peroxide. It is very important for the dairy industry to understand how bleaching can impact flavor and functionality of dried ingredients. Currently, the precise mechanisms of off-flavor development and functionality changes are not entirely understood. Iron reactions in a bleached liquid whey system may play a key role. Reactions between iron and hydrogen peroxide have been widely studied since the reaction between these 2 relatively stable species can cause great destruction in biological and chemical systems. The actual mechanism of the reaction of iron with hydrogen peroxide has been a controversy in the chemistry and biological community. The precise mechanism for a given reaction can vary greatly based upon the concentration of reactants, temperature, pH, and addition of biological material. In this review, some hypotheses for the mechanisms of iron reactions that may occur in fluid whey that may impact bleaching efficacy, off-flavor development, and changes in functionality are presented. Cheese whey is bleached to remove residual carotenoid cheese colorant. Concerns regarding bleaching efficacy, off-flavor development, and functionality changes have

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

    PubMed

    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. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  19. Benzoylated ethyl 1-thioglycosides: direct preparation from per-O-benzoylated sugars

    PubMed Central

    Sail, Deepak; Kováč, Pavol

    2012-01-01

    D-Glucose, lactose, maltose, and melibiose were benzoylated with Bz2O–Et3N reagent to give fully benzoylated β products. Under the same conditions, D-mannose produced a mixture where the β-benzoate predominated. Treatment of the foregoing compounds with EtSH at slightly elevated temperature (50– 60 °C) in the presence of BF3·Et2O as a promoter gave the corresponding ethyl 1-thio glycosides in high yields. The α-products predominated in all cases in the anomeric mixtures formed. Individual products of all reactions were isolated by chromatography, they were obtained in analytically pure state, and were fully characterized by 1H and 13C NMR data and physical constants. PMID:22739243

  20. Benzoylated ethyl 1-thioglycosides: direct preparation from per-O-benzoylated sugars.

    PubMed

    Sail, Deepak; Kováč, Pavol

    2012-08-01

    D-Glucose, lactose, maltose, and melibiose were benzoylated with Bz(2)O-Et(3)N reagent to give fully benzoylated β products. Under the same conditions, D-mannose produced a mixture where the β-benzoate predominated. Treatment of the foregoing compounds with EtSH at slightly elevated temperature (50-60°C) in the presence of BF(3)·Et(2)O as a promoter gave the corresponding ethyl 1-thio glycosides in high yields. The α-products predominated in all cases in the anomeric mixtures formed. Individual products of all reactions were isolated by chromatography, they were obtained in analytically pure state, and were fully characterized by (1)H and (13)C NMR data and physical constants. Published by Elsevier Ltd.

  1. Evaluation of the efficacy, tolerability, and safety of an over-the-counter acne regimen containing benzoyl peroxide and salicylic acid in subjects with acne.

    PubMed

    Kircik, Leon H; Gwazdauskas, Jennifer; Butners, Victoria; Eastern, Joseph; Green, Lawrence J

    2013-03-01

    Benzoyl peroxide (BPO) is a widely used over-the-counter (OTC) topical acne treatment often used in combination with salicylic acid (SA) to achieve better comedone control than that achieved with BPO alone. MaxClarity™ is an OTC acne treatment system comprising BPO and SA in an aqueous foam delivery vehicle, VersaFoam AF™. This paper describes 2 open-label, single-arm studies conducted to assess the efficacy, safety, tolerability, and patient preference of MaxClarity in the treatment of mild, moderate, and severe acne. Subjects applied MaxClarity twice daily for 8 weeks in study 402 and for 12 weeks in study 405. Reductions in all lesion types were seen throughout both studies. At week 8 (study 402), there was a mean reduction from baseline of -56.9 ± 32.7% in total lesions in subjects with mild, moderate, or severe acne. At week 12 (study 405), there was a reduction from baseline of -61.6 ± 22.0% in total lesions in subjects with moderate or severe acne. Overall, both studies demonstrated that MaxClarity is a generally well tolerated and effective treatment for mild, moderate, and severe acne.

  2. Preparation and Cyclodextrin Solubilization of the Antibacterial Agent Benzoyl Metronidazole

    PubMed Central

    Yang, Shuo

    2013-01-01

    A one-pot method for the preparation of benzoyl metronidazole was achieved by using N,N′-carbonyldiimidazole as a coupling reagent. Moreover, it was found that the byproduct imidazole as the catalyst promoted the reaction. In addition, the β-cyclodextrin solubilization of benzoyl metronidazole was investigated by phase-solubility method. The phase-solubility studies indicated that the solubility of benzoyl metronidazole (S = 0.1435 g/L) was substantially increased 9.7-fold (S′ = 1.3881 g/L) by formation of 1 : 1 benzoyl metronidazole/β-cyclodextrin complexes in water, and the association constant K a value was determined to be 251 (±23) dm3/mol. Therefore, β-cyclodextrin can work as a pharmaceutical solubilizer for benzoyl metronidazole and may improve its oral bioavailability. PMID:23970831

  3. A double-blind, randomized, bilateral comparison of skin irritancy following application of the combination acne products clindamycin/tretinoin and benzoyl peroxide/adapalene.

    PubMed

    Goreshi, Renato; Samrao, Aman; Ehst, Benjamin D

    2012-12-01

    The use of topical medications for acne vulgaris is often limited by their irritant properties. Newer combination preparations are available and offer convenience, but irritant potential may still be a hindrance, perhaps more so with the combination of 2 agents. Few studies have compared these formulations directly for tolerability. We sought to compare the tolerability of 2 combination topical acne products, clindamycin 1.2%-tretinoin 0.025% (CLIN/RA) gel and benzoyl peroxide 2.5%-adapalene 0.1% (BPO/ADA) gel. CLIN/RA and BPO/ADA were applied daily to opposite sides of a subject's face for 21 days in a double-blinded fashion. Investigators' Global Assessments and study subject self-assessments of burning/stinging, itching, erythema, and dryness/scaling were collected. Transepidermal water loss (TEWL) was also measured as an objective measure of skin irritation. A mixed model analysis and repeated-measures analysis of variance were used to compare outcomes for both acne formulations. CLIN/RA produced significantly less burning/stinging than BPO/ADA (P<.001) as well as significantly less pruritus than BPO/ ADA (P<.001). BPO/ADA caused significantly more TEWL than CLIN/RA (P=.005). There was no significant difference in the amount of erythema or the amount of dryness/scaling caused by either formulation. CLIN/RA produced significantly less skin irritancy and TEWL than BPO/ADA.

  4. Randomized tolerability analysis of clindamycin phosphate 1.2%-tretinoin 0.025% gel used with benzoyl peroxide wash 4% for acne vulgaris.

    PubMed

    Draelos, Zoe Diana; Potts, Aaron; Alió Saenz, Alessandra B

    2010-12-01

    The multiple etiologic factors involved in acne vulgaris make the use of several medications necessary to treat the condition. Use of a fixed combination of clindamycin phosphate 1.2% and tretinoin 0.025% in conjunction with a benzoyl peroxide (BPO) wash 4% targets several pathologic factors simultaneously and mitigates the potential for clindamycin-induced Propionibacterium acnes-resistant strains. New formulations may allow such regimens to be effectively used without overly reduced tolerability resulting from the irritation potential of tretinoin and BPO. This randomized, single-blind study investigated the local tolerability, irritation potential, and safety of an aqueous-based gel (clindamycin phosphate 7.2%-tretinoin 0.025% [CT gel]) when used in conjunction with a BPO wash 4% in participants with mild to moderate acne vulgaris. Participants applied the CT gel once daily in the evening for 4 weeks in conjunction with once-daily morning use of either BPO wash 4% or nonmedicated soap-free cleanser lotion (SFC). Local tolerability and irritation potential were assessed by participants and investigators using separate 6-point scales. The frequency and severity of dryness, scaling, erythema, burning/stinging, and itching increased during the first week of treatment in both treatment arms but decreased thereafter. Local tolerability reactions were slightly more frequent in the CT gel + BPO wash group versus the CT gel + SFC group at week 1 but were generally mild and improved within 1 to 2 weeks. In conclusion, therapy with CT gel + BPO wash appears safe and well-tolerated in participants with mild to moderate acne vulgaris.

  5. Systemic exposure to benzoic acid and hippuric acid following topical application of clindamycin 1%/benzoyl peroxide 3% fixed-dose combination gel in Japanese patients with acne vulgaris.

    PubMed

    Ino, Hiroko; Takahashi, Naoki; Saenz, Alessandra Alio; Wakamatsu, Akira; Hashimoto, Hirofumi; Nakahara, Norie; Hasegawa, Setsuo

    2015-01-01

    Clindamycin 1%/benzoyl peroxide 3% fixed-dose combination gel (CLDM/BPO3%) is a topical product for the treatment of acne vulgaris. In this study, plasma and urine concentrations of benzoic acid (BA) and hippuric acid (HA) were analyzed to estimate the pharmacokinetics (PK) of BPO after application of CLDM/BPO3% twice-daily for 7 days in Japanese patients with acne vulgaris. Seven-day repeated application of CLDM/BPO3% appears to be safe in this patient population. Concentrations of plasma and urine BA were below the limit of quantification before and after repeated application in most of the 12 adult male patients. Mean difference in Cmax and AUC0-last for plasma HA indicated increased exposures after repeated application, but with wide 90% confidence intervals. Mean Ae0-12 for urine HA was similar before and after repeated application. Repeated application of CLDM/BPO3% is thus unlikely to result in accumulation of BA and HA. The study suggests negligible systemic exposure to BPO metabolites from CLDM/BPO3% after 7-day repeated application in male patients with acne vulgaris. © 2014, The American College of Clinical Pharmacology.

  6. [Carcinogenicity in mice by inhalation of benzotrichloride and benzoyl chloride].

    PubMed

    Yoshimura, H; Takemoto, K; Fukuda, K; Matsushita, H

    1986-09-01

    Benzotrichloride and benzoyl chloride are suspected to be causative agents of lung cancer and maxillary malignant lymphoma of workers employed in factories producing benzoyl chloride. The present study was undertaken to evaluate the carcinogenicity in mice of inhaling benzotrichloride and benzoyl chloride. Mice inhaled benzotrichloride and benzoyl chloride vapor for 30 min/d for 2 d/wk for 5 months, and each animal was followed for several month without subsequent exposure. Tumor developed in the lung, skin and lymphatic tissues at high incidences in mice inhaling benzotrichloride. By benzotrichloride vaporized at 50 degrees C, the incidence of pulmonary tumors was 53.1% (17/32, p less than 0.001), that of skin tumors was 25% (8/32, p less than 0.02), and that of malignant lymphoma was 25% (8/32, p less than 0.02) observed at the 10th month after exposure. These are significantly higher than that observed in control mice. In mice exposed to benzotrichloride vaporized at room temperature, the incidence of pulmonary tumors was 81.1% (30/37), that of skin tumors was 27.0% (10/37), and that of malignant lymphoma was 10.8% (4/37) observed at the 15th month after exposure. On the other hand, by benzoyl chloride vaporized at 50 degrees C, the incidence of pulmonary tumors was 10.7% (3/28) and that of skin tumors was 7.1% (2/28), but these incidences did not show any significant difference from the controls. These results suggest that the carcinogenicity of benzotrichloride is much higher than benzoyl chloride and that benzotrichloride is the primary cause of malignancies developing among workers engaged in manufacturing benzoyl chloride.

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

    PubMed

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

    2003-02-14

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

  8. Tretinoin gel microsphere pump 0.04% plus 5% benzoyl peroxide wash for treatment of acne vulgaris: morning/morning regimen is as effective and safe as morning/evening regimen.

    PubMed

    Pariser, David; Bucko, Alicia; Fried, Richard; Jarratt, Michael T; Kempers, Steven; Kircik, Leon; Lucky, Anne W; Rafal, Elyse; Rendon, Marta; Weiss, Jonathan; Wilson, David C; Rossi, Ana Beatris; Ramaswamy, Ratna; Nighland, Marge

    2010-07-01

    Topical tretinoin and benzoyl peroxide (BPO) are often prescribed in combination for the treatment of acne vulgaris; however, these products have not traditionally been administered simultaneously because of the potential for tretinoin degradation by BPO as well as the instability of tretinoin in daylight. The primary objective of this randomized, investigator-blinded, 12-week, phase 4 trial was to determine non-inferiority of a once-daily morning combination regimen of 5% BPO wash + tretinoin gel microsphere (TGM) 0.04% pump versus a sequential regimen (BPO in the morning/TGM in the evening) in patients > or = 12 years old with moderate facial acne vulgaris. The primary efficacy endpoint was the change from baseline in total acne lesions; the primary safety endpoint was the change in cutaneous irritation scores. The 247 participants (mean age: 18.5 years) were randomized to either the morning/morning regimen (n = 123) or the morning/evening regimen (n = 124). The morning/morning regimen was determined to be non-inferior to the morning/evening regimen in reduction of total acne lesions. The tolerability of both regimens was comparable. The morning/morning regimen is a safe and effective treatment option for patients with moderate acne vulgaris.

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

    PubMed

    Lu, Yuchao; Hou, Chenxi; Ren, Jingli; Xin, Xiaoting; Xu, Hengfu; Pei, Yuxin; Dong, Hai; Pei, Zhichao

    2016-05-17

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

  10. AuBr3-catalyzed azidation of per-O-acetylated and per-O-benzoylated sugars.

    PubMed

    Rajput, Jayashree; Hotha, Srinivas; Vangala, Madhuri

    2018-01-01

    Herein we report, for the first time, the successful anomeric azidation of per- O -acetylated and per- O -benzoylated sugars by catalytic amounts of oxophilic AuBr 3 in good to excellent yields. The method is applicable to a wide range of easily accessible per- O -acetylated and per- O -benzoylated sugars. While reaction with per- O -acetylated and per- O -benzoylated monosaccharides was complete within 1-3 h at room temperature, the per- O -benzoylated disaccharides needed 2-3 h of heating at 55 °C.

  11. Characterization of Benzoyl Coenzyme A Biosynthesis Genes in the Enterocin-Producing Bacterium “Streptomyces maritimus”

    PubMed Central

    Xiang, Longkuan; Moore, Bradley S.

    2003-01-01

    The novel benzoyl coenzyme A (benzoyl-CoA) biosynthesis pathway in “Streptomyces maritimus” was investigated through a series of target-directed mutations. Genes involved in benzoyl-CoA formation were disrupted through single-crossover homologous recombination, and the resulting mutants were analyzed for their ability to biosynthesize the benzoyl-CoA-primed polyketide antibiotic enterocin. Inactivation of the unique phenylalanine ammonia-lyase-encoding gene encP was previously shown to be absolutely required for benzoyl-CoA formation in “S. maritimus”. The fatty acid β-oxidation-related genes encH, -I, and -J, on the other hand, are necessary but not required. In each case, the yield of benzoyl-CoA-primed enterocin dropped below wild-type levels. We attribute the reduced benzoyl-CoA formation in these specific mutants to functional substitution and cross-talk between the products of genes encH, -I, and -J and the enzyme homologues of primary metabolism. Disruption of the benzoate-CoA ligase encN gene did not perturb enterocin production, however, demonstrating that encN is extraneous and that benzoic acid is not a pathway intermediate. EncN rather serves as a substitute pathway for utilizing exogenous benzoic acid. These experiments provide further support that benzoyl-CoA is formed in a novel bacterial pathway that resembles the eukaryotic assembly of benzoyl-CoA from phenylalanine via a β-oxidative path. PMID:12511484

  12. Effect of N-benzoyl-d-phenylalanine on lipid profile in liver of neonatal streptozotocin diabetic rats.

    PubMed

    Pari, Leelavinothan; Ashokkumar, Natarajan

    2005-10-01

    The effect of N-benzoyl-d-phenylalanine (NBDP) and metformin combination treatment on liver lipids and lipid peroxidation markers was studied in neonatal streptozotocin (nSTZ) diabetic rats. Oral administration of NBDP (50, 100 and 200 mg/kg body weight) and metformin (500 mg/kg body weight) for 6 weeks significantly reduced the elevated blood glucose, liver cholesterol, triglycerides, free fatty acids and phospholipids. The combination treatment also caused a significant decrease in hepatic hydroxymethyl glutaryl-coenzyme A reductase, Thiobarbituric Acid Reactive Substances (TBARS) and significant increase in reduced glutathione levels. The results show that NBDP and metformin improve the hepatic lipid profile and antioxidant status in nSTZ diabetic rats. Combination treatment was more effective than either drug alone.

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

    PubMed

    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.

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

    PubMed Central

    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/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 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. PMID

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

    DOE PAGES

    Eudes, Aymerick; Teixeira Benites, Veronica; Wang, George; ...

    2015-10-02

    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 anthranilatesmore » 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. Finally, 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.« less

  16. Effect of N-benzoyl-D-phenylalanine on streptozotocin-induced changes in the lipid and lipoprotein profile in rats.

    PubMed

    Ashokkumar, N; Pari, L; Manimekalai, A; Selvaraju, K

    2005-03-01

    The effect of N-benzoyl-D-phenylalanine (NBDP) and metformin combination treatment on circulatory lipids, lipoproteins and lipid peroxidation markers were studied in neonatal streptozotocin (nSTZ) non-insulin dependent diabetic rats. Non-insulin dependent diabetes mellitus (NIDDM) was induced by a single dose injection of streptozotocin (100 mg kg(-1), i. p.) to two-day-old rats. After 10-12 weeks, rats weighing above 150 g were selected for screening for the NIDDM model. The rats were checked for fasting blood glucose levels to confirm the status of NIDDM. NBDP (50,100 or 200 mg kg(-1) ) was administered orally for six weeks to the confirmed diabetic rats (to evaluate the effective dose). The levels of serum lipids and lipid peroxidation markers were significantly increased, whilst the activity of glucose-6-phosphate dehydrogenase was significantly decreased in nSTZ diabetic rats. NBDP and metformin were able to restore the altered serum lipids, lipoproteins, lipid peroxidation marker levels and glucose-6-phosphate dehydrogenase activity to almost control levels. The results showed the antihyperlipidaemic properties of NBDP and metformin in addition to its antidiabetic action. Combination treatment was more effective then either drug alone. The results indicated that the coadministration of NBDP with metformin to nSTZ diabetic rats normalized blood glucose and caused marked improvement in altered serum lipids, lipoproteins and lipid peroxidation markers during diabetes. The data indicated that NBDP represented an effective antihyperglycaemic and antihyperlipidaemic adjunct for the treatment of diabetes, and may be a potential source of new orally active agents for future therapy.

  17. Acne

    MedlinePlus

    ... a cream or lotion with benzoyl peroxide, resorcinol, salicylic acid, or sulfur. Benzoyl peroxide works to reduce oil made by the glands. Resorcinol, salicylic acid, and sulfur help breakdown whiteheads and blackheads. If ...

  18. X-ray investigations of sulfur-containing fungicides. IV. 4'-[[Benzoyl(4-chlorophenylhydrazono)methyl]sulfonyl]acetanilide and 4'-[[benzoyl(4-methoxyphenylhydrazono)methyl]sulfonyl]acetanilide.

    PubMed

    Wolf, W M

    2001-09-01

    The conformations of the two approximately isomorphous structures 4'-[[benzoyl(4-chlorophenylhydrazono)methyl]sulfonyl]acetanilide, C(22)H(18)ClN(3)O(4)S, and 4'-[[benzoyl(4-methoxyphenylhydrazono)methyl]sulfonyl]acetanilide, C(23)H(21)N(3)O(5)S, are stabilized by resonance-assisted intramolecular hydrogen bonds linking the hydrazone moieties and sulfonyl groups. The stronger bond is observed in the former compound. The difference in electronic properties between the Cl atom and the methoxy group is too small to significantly alter the non-bonding interactions of the sulfonyl and beta-carbonyl groups.

  19. Acne

    MedlinePlus

    ... may contain benzoyl peroxide, sulfur, resorcinol, adapalene, or salicylic acid. They work by killing bacteria, drying up skin ... Prescription formulas of benzoyl peroxide, sulfur, resorcinol, or salicylic acid Topical azelaic acid For women whose acne is ...

  20. Topical Acne Treatments and Pregnancy

    MedlinePlus

    ... are benzoyl peroxide, azelaic acid, glycolic acid, and salicylic acid. Prescription acne medications include tretinoin, adapalene, dapsone, and ... ACOG) recommends topical benzoyl peroxide, azelaic acid, topical salicylic acid and glycolic acid for treatment of acne in ...

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

    PubMed

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

    2015-01-01

    A novel amphipathic chitosan derivative, N-benzoyl-O-acetyl-chitosan (BACS), was prepared by using the selective partial acylation of chitosan (CS), benzoyl chloride, and acetic acid under high-intensity ultrasound. The chemical structure and physical properties of BACS were characterized by FTIR, (1)H NMR, TGA, and XRD techniques. The degrees of substitution of benzoyl and acetyl for the chitosan derivatives were 0.26 and 1.15, respectively, which were calculated from the peak areas in NMR spectra by using the combined integral methods. The foaming properties of CS and BACS were determined and the results suggested BACS had better foam capacity and stability than those of chitosan. In addition, the antimicrobial activities of CS and BACS were also investigated against two species of bacteria (Escherichia coli and Staphylococcus aureus) and a fungus (Aspergillus niger), the results indicated that the antibacterial and antifungal activities of BACS were much stronger than those of the parent chitosan. These findings suggested that BACS was preferable for use as a food additive with a dual role of both foaming agent and food preservative. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Twelve-week, multicenter, placebo-controlled, randomized, double-blind, parallel-group, comparative phase II/III study of benzoyl peroxide gel in patients with acne vulgaris: A secondary publication.

    PubMed

    Kawashima, Makoto; Sato, Shinichi; Furukawa, Fukumi; Matsunaga, Kayoko; Akamatsu, Hirohiko; Igarashi, Atsuyuki; Tsunemi, Yuichiro; Hayashi, Nobukazu; Yamamoto, Yuki; Nagare, Toshitaka; Katsuramaki, Tsuneo

    2017-07-01

    A placebo-controlled, randomized, double-blind, parallel-group, comparative, multicenter study was conducted to investigate the efficacy and safety of benzoyl peroxide (BPO) gel, administrated once daily for 12 weeks to Japanese patients with acne vulgaris. Efficacy was evaluated by counting all inflammatory and non-inflammatory lesions. Safety was evaluated based on adverse events, local skin tolerability scores and laboratory test values. All 609 subjects were randomly assigned to receive the study products (2.5% and 5% BPO and placebo), and 607 subjects were included in the full analysis set, 544 in the per protocol set and 609 in the safety analyses. The median rates of reduction from baseline to the last evaluation of the inflammatory lesion counts, the primary end-point, in the 2.5% and 5% BPO groups were 72.7% and 75.0%, respectively, and were significantly higher than that in the placebo group (41.7%). No deaths or other serious adverse events were observed. The incidences of adverse events in the 2.5% and 5% BPO groups were 56.4% and 58.8%, respectively; a higher incidence than in the placebo group, but there was no obvious difference between the 2.5% and 5% BPO groups. All adverse events were mild or moderate in severity. Most adverse events did not lead to study product discontinuation. The results suggested that both 2.5% and 5% BPO are useful for the treatment of acne vulgaris. © 2017 The Authors. The Journal of Dermatology published by John Wiley & Sons Australia, Ltd.

  3. Gas-phase cationic benzoylation of ambient aromatic substrates studied with the decay technique

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Occhiucci, G.; Cacace, F.; Speranza, M.

    1986-03-05

    The gas-phase benzoylation of typical ambient aromatic substrates PhY (Y = OH, OMe, and NH/sub 2/) has been investigated by a combination of the decay technique and of FT ICR mass spectrometry. Labeled phenylium ions, C/sub 6/X/sub 5//sup +/ (X = H and T), from the decay of multiply tritiated benzene, C/sub 6/X/sub 6/, have been allowed to react with excess CO-containing traces of PhY (Y = OH, OMe, and NH/sub 2/), in the pressure range from 90 to 650 torr. Radio GLC and HPLC of the tritiated products demonstrate two competitive reaction channels, i.e., phenylation and benzoylation of themore » aromatic substrates. The results indicate a sharp kinetic bias of the gaseous phenylium ions for the aromatic substrates, measured by an apparent k/sub CO//k/sub PhY/ ratio of 0.12 (Y = OH), 0.13 (Y = OMe), and 0.04 (Y = NH/sub 2/) in the systems at nearly atmospheric pressure. Gas-phase benzoylation displays a high intramolecular selectivity, occurring exclusively at the n-type center of PhOH and PhNH/sub 2/. In the case of PhOMe, appreciable ring benzoylation is observed, characterized by a remarkably high (up to 30:1) bias for the para position. The mechanistic features of the gas-phase benzoylation and phenylation processes, deduced from the decay and the ICR experiments, are discussed and compared with those of related aromatic acylation and alkylation reactions occurring in the dilute gas state. 30 references, 2 tables.« less

  4. Deformation and Thermal Properties of Energetic Materials.

    DTIC Science & Technology

    1980-12-01

    have done some experiments in which they find that tetramethylammonium tribo- hydride (a free radical donor) causes increased reaction with ammonium ... nitrate . In order to test this hypothesis, mixtures of benzoyl peroxide and PETN were used in a series of TG experiments. Benzoyl peroxide is an...thec Lui~ycr;1 i that ;1 pol1 m\

  5. 21 CFR 172.814 - Hydroxylated lecithin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) With hydrogen peroxide, benzoyl peroxide, lactic acid, and sodium hydroxide. (2) With hydrogen peroxide, acetic acid, and sodium hydroxide. (b) It is used or intended for use, in accordance with good...

  6. 21 CFR 172.814 - Hydroxylated lecithin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) With hydrogen peroxide, benzoyl peroxide, lactic acid, and sodium hydroxide. (2) With hydrogen peroxide, acetic acid, and sodium hydroxide. (b) It is used or intended for use, in accordance with good...

  7. Open-label, randomized, multicenter, phase III study to evaluate the safety and efficacy of benzoyl peroxide gel in long-term use in patients with acne vulgaris: A secondary publication.

    PubMed

    Kawashima, Makoto; Nagare, Toshitaka; Katsuramaki, Tsuneo

    2017-06-01

    An open-label, randomized, multicenter study was conducted to evaluate the safety and efficacy of long-term use of 2.5% and 5% benzoyl peroxide (BPO) gels administrated once daily for 52 weeks to Japanese patients with acne vulgaris. The efficacy of the study drugs was evaluated by counting inflammatory lesions and non-inflammatory lesions. Safety was evaluated based on adverse events, local skin tolerability scores and laboratory test values. In total, 458 subjects were included in the efficacy and safety analyses. The total lesion count, the efficacy end-point, was similarly changed both in the 2.5% and 5% BPO groups over the course of the study. The median rates of reduction from baseline to week 12 were approximately 65%. Thereafter, the counts were maintained at a reduced level without increasing until week 52. The median rates at week 52 were approximately 80%. Similar trends were observed for inflammatory and non-inflammatory lesion counts. Bacteriological evaluation indicated similar distribution of the minimum inhibitory concentration of each of the antibacterial drugs against Propionibacterium acnes between the values at baseline and at week 52, suggesting that long-term use did not result in changes in the drug sensitivity. The incidence of adverse events was 84.0% in the 2.5% BPO group and 87.2% in the 5% BPO group. Many of the adverse events occurred within the first month and were mild or moderate in severity and transient. The results suggest that both 2.5% and 5% BPO gels are effective and safe for long-term treatment of patients with acne vulgaris. © 2017 The Authors. The Journal of Dermatology published by John Wiley & Sons Australia, Ltd on behalf of Japanese Dermatological Association.

  8. Erythromycin and Benzoyl Peroxide Topical

    MedlinePlus

    ... on to step 5. If your medication comes in small pouches, use scissors or your fingers to tear off the top at the notched tab. Do not open the pouch with your teeth. Squeeze the contents of the pouch onto your ...

  9. Benzoate Metabolism Intermediate Benzoyl Coenzyme A Affects Gentisate Pathway Regulation in Comamonas testosteroni

    PubMed Central

    Chen, Dong-Wei; Zhang, Yun; Jiang, Cheng-Ying

    2014-01-01

    A previous study showed that benzoate was catabolized via a coenzyme A (CoA)-dependent epoxide pathway in Azoarcus evansii (R. Niemetz, U. Altenschmidt, S. Brucker, and G. Fuchs, Eur. J. Biochem. 227:161-168, 1995), but gentisate 1,2-dioxygenase was induced. Similarly, we found that the Comamonas testosteroni strain CNB-1 degraded benzoate via a CoA-dependent epoxide pathway and that gentisate 1,2-dioxygenase (GenA) was also induced when benzoate or 3-hydroxybenzoate served as a carbon source for growth. Genes encoding the CoA-dependent epoxide (box genes) and gentisate (gen genes) pathways were identified. Genetic disruption revealed that the gen genes were not involved in benzoate and 3-hydroxybenzoate degradation. Hence, we investigated gen gene regulation in the CNB-1 strain. The PgenA promoter, a MarR-type regulator (GenR), and the GenR binding site were identified. We found that GenR took gentisate, 3-hydroxybenzoate, and benzoyl-CoA as effectors and that binding of GenR to its target DNA sequence was prohibited when these effectors were present. In vivo studies showed that the CNB-1 mutant that lost benzoyl-CoA synthesis was not able to activate PgenA promoter, while transcription of genA was upregulated in another CNB-1 mutant that lost the ability to degrade benzoyl-CoA. The finding that benzoyl-CoA (a metabolic intermediate of benzoate degradation) and 3-hydroxybenzoate function as GenR effectors explains why GenA was induced when CNB-1 grew on benzoate or 3-hydroxybenzoate. Regulation of gentisate pathways by MarR-, LysR-, and IclR-type regulators in diverse bacterial groups is discussed in detail. PMID:24771026

  10. Acne -- self-care

    MedlinePlus

    ... It may help to use a wash with salicylic acid or benzoyl if your skin is oily and ... products may contain benzoyl peroxide, sulfur, resorcinol, or salicylic acid. They work by killing bacteria, drying up skin ...

  11. Photoaffinity labeling of the TF1-ATPase from the thermophilic bacterium PS3 with 3'-O-(4-benzoyl)benzoyl ADP.

    PubMed

    Bar-Zvi, D; Yoshida, M; Shavit, N

    1985-05-31

    3'-O-(4-Benzoyl)benzoyl ADP (BzADP) was used as a photoaffinity label for covalent binding of adenine nucleotide analogs to the nucleotide binding site(s) of the thermophilic bacterium PS3 ATPase (TF1). As with the CF1-ATPase (Bar-Zvi, D. and Shavit, N. (1984) Biochim. Biophys. Acta 765, 340-356) noncovalently bound BzADP is a reversible inhibitor of the TF1-ATPase. BzADP changes the kinetics of ATP hydrolysis from noncooperative to cooperative in the same way as ADP does, but, in contrast to the effect on the CF1-ATPase, it has no effect on the Vmax. In the absence of Mg2+ 1 mol BzADP binds noncovalently to TF1, while with Mg2+ 3 mol are bound. Photoactivation of BzADP results in the covalent binding of the analog to the nucleotide binding site(s) on TF1 and correlates with the inactivation of the ATPase. Complete inactivation of the TF1-ATPase occurs after covalent binding of 2 mol BzADP/mol TF1. Photoinactivation of TF1 by BzADP is prevented if excess of either ADP or ATP is present during irradiation. Analysis by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate of the Bz[3H]ADP-labeled TF1-ATPase shows that all the radioactivity is incorporated into the beta subunit.

  12. 40 CFR 721.10166 - 1,3-Cyclohexanedione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1). 721.10166 Section 721...(1-), potassium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1...-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1) (PMN P-08-180; CAS No. 1121649-70-4) is subject to...

  13. 40 CFR 721.10166 - 1,3-Cyclohexanedione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1). 721.10166 Section 721...(1-), potassium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1...-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1) (PMN P-08-180; CAS No. 1121649-70-4) is subject to...

  14. 40 CFR 721.10166 - 1,3-Cyclohexanedione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1). 721.10166 Section 721...(1-), potassium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1...-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1) (PMN P-08-180; CAS No. 1121649-70-4) is subject to...

  15. 40 CFR 721.10166 - 1,3-Cyclohexanedione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1). 721.10166 Section 721...(1-), potassium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1...-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1) (PMN P-08-180; CAS No. 1121649-70-4) is subject to...

  16. 40 CFR 721.10166 - 1,3-Cyclohexanedione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1). 721.10166 Section 721...(1-), potassium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1...-trifluoroethoxy)methyl]benzoyl]-, ion(1-), potassium salt (1:1) (PMN P-08-180; CAS No. 1121649-70-4) is subject to...

  17. 21 CFR 172.814 - Hydroxylated lecithin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... resultant product has an acetyl value of 30 to 38: (1) With hydrogen peroxide, benzoyl peroxide, lactic acid, and sodium hydroxide. (2) With hydrogen peroxide, acetic acid, and sodium hydroxide. (b) It is used or...

  18. 4D Interconnect Experimental Development

    DTIC Science & Technology

    1993-06-29

    Polymerization of MMA Using Benzoyl Peroxide ..... .......... 6 2.1.2.3 Polymerization Using Benzoin ........ .................. 7 2.1.3 Adding the SHB...molecules.J6l This breakdown can be driven thermally (as in the case of benzoyl peroxide) or via UV illumination (as in the case of benzoin ). Once...taken is increased. 6 2.1.2.3 Polymerization Using Benzoin A commonly used alternative to the initiation being driven thermally is to use a photoini

  19. Hydrogen bonding pattern in N-benzoyl(- DL-)- L-phenylalanines as revealed by solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Potrzebowski, M. J.; Schneider, C.; Tekely, P.

    1999-11-01

    The nature of the hydrogen bonding pattern has been investigated in N-benzoyl- DL-phenylalanine ( 1) and N-benzoyl- L-phenylalanine ( 2) polymorphes by solid-state NMR spectroscopy. It has been shown that the multiple resonances of carboxyl carbon in 2 are directly connected to different types of hydrogen bonding. The differences in intermolecular distances of carboxyl groups involved in different types of hydrogen bonding have been visualized by the 2D exchange and 1D ODESSA experiments. Potential applications of such a new approach include the exploration of intermolecular distances in hydrogen bonded compounds with singly labeled biomolecules.

  20. Structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogs in a microbial antitumor prescreen I: Derivatives of o-fluoro-DL-phenylalanine.

    PubMed

    Otani, T T; Briley, M R

    1982-02-01

    Twelve derivatives of 0-fluoro-dl-phenylalanine containing fluorine, chlorine, methoxy, and nitro radicals in various positions of the aromatic ring of the benzoyl group were prepared and tested in a Lactobacillus casei system. It was found that most substitutions in the benzoyl phenyl ring resulted in a compound exhibiting greater growth-inhibiting activity than the nonsubstituted benzoyl-o-fluorophenylalanine. The greatest activity was observed in the ortho-substituted fluoro compound and the meta- and para-substituted chloro and nitro compounds. With the methoxy group, the position of substitution appeared unimportant, since all three methoxy isomers exhibited essentially equal inhibition. Nitro substitution in the ortho position had a protective effect in that the product was less active than the unsubstituted benzoyl-o-fluoro-dl-phenylalanine.

  1. Copper-Catalyzed Electrophilic Amination of Organoaluminum Nucleophiles with O-Benzoyl Hydroxylamines.

    PubMed

    Zhou, Shuangliu; Yang, Zhiyong; Chen, Xu; Li, Yimei; Zhang, Lijun; Fang, Hong; Wang, Wei; Zhu, Xiancui; Wang, Shaowu

    2015-06-19

    A copper-catalyzed electrophilic amination of aryl and heteroaryl aluminums with N,N-dialkyl-O-benzoyl hydroxylamines that affords the corresponding anilines in good yields has been developed. The catalytic reaction proceeds very smoothly under mild conditions and exhibits good substrate scope. Moreover, the developed catalytic system is also well suited for heteroaryl aluminum nucleophiles, providing facile access to heteroaryl amines.

  2. 21 CFR 184.1157 - Benzoyl peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ....181), Romano cheese (§ 133.183), and Swiss and emmentaler cheese (§ 133.195) in part 133 of this...; milk used for production of Asiago fresh and Asiago soft cheese (§ 133.102), Asiago medium cheese (§ 133.103), Asiago old cheese (§ 133.104), Blue cheese (§ 133.106), Caciocavallo siciliano chesse (§ 133...

  3. 21 CFR 184.1157 - Benzoyl peroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ....181), Romano cheese (§ 133.183), and Swiss and emmentaler cheese (§ 133.195) in part 133 of this...; milk used for production of Asiago fresh and Asiago soft cheese (§ 133.102), Asiago medium cheese (§ 133.103), Asiago old cheese (§ 133.104), Blue cheese (§ 133.106), Caciocavallo siciliano chesse (§ 133...

  4. 21 CFR 184.1157 - Benzoyl peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....181), Romano cheese (§ 133.183), and Swiss and emmentaler cheese (§ 133.195) in part 133 of this...; milk used for production of Asiago fresh and Asiago soft cheese (§ 133.102), Asiago medium cheese (§ 133.103), Asiago old cheese (§ 133.104), Blue cheese (§ 133.106), Caciocavallo siciliano chesse (§ 133...

  5. 21 CFR 184.1157 - Benzoyl peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ....181), Romano cheese (§ 133.183), and Swiss and emmentaler cheese (§ 133.195) in part 133 of this...; milk used for production of Asiago fresh and Asiago soft cheese (§ 133.102), Asiago medium cheese (§ 133.103), Asiago old cheese (§ 133.104), Blue cheese (§ 133.106), Caciocavallo siciliano chesse (§ 133...

  6. 21 CFR 184.1157 - Benzoyl peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....181), Romano cheese (§ 133.183), and Swiss and emmentaler cheese (§ 133.195) in part 133 of this...; milk used for production of Asiago fresh and Asiago soft cheese (§ 133.102), Asiago medium cheese (§ 133.103), Asiago old cheese (§ 133.104), Blue cheese (§ 133.106), Caciocavallo siciliano chesse (§ 133...

  7. 1,2-diketones promoted degradation of poly(epsilon-caprolactone)

    NASA Astrophysics Data System (ADS)

    Danko, Martin; Borska, Katarina; Ragab, Sherif Shaban; Janigova, Ivica; Mosnacek, Jaroslav

    2012-07-01

    Photochemical reactions of Benzil and Camphorquinone were used for modification of poly(ɛ-caprolactone) polymer films. Photochemistry of dopants was followed by infrared spectroscopy, changes on polymer chains of matrix were followed by gel permeation chromatography. Benzoyl peroxide was efficiently photochemically generated from benzyl in solid polymer matrix in the presence of air. Following decomposition of benzoyl peroxide led to degradation of matrix. Photochemical transformation of benzil in vacuum led to hydrogen abstraction from the polymer chains in higher extent, which resulted to chains recombination and formation of gel. Photochemical transformation of camphorquinone to corresponding camphoric peroxide was not observed. Only decrease of molecular weight of polymer matrix doped with camphorquinone was observed during the irradiation.

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

    PubMed

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

    2015-03-21

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

  9. 21 CFR 172.814 - Hydroxylated lecithin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... whereby the separated fatty acid fraction of the resultant product has an acetyl value of 30 to 38: (1) With hydrogen peroxide, benzoyl peroxide, lactic acid, and sodium hydroxide. (2) With hydrogen peroxide, acetic acid, and sodium hydroxide. (b) It is used or intended for use, in accordance with good...

  10. Erythema-directed digital photography for the enhanced evaluation of topical treatments for acne vulgaris.

    PubMed

    Micali, G; Dall'Oglio, F; Tedeschi, A; Lacarrubba, F

    2018-01-31

    Erythema-directed digital photography is a novel method for evaluating the efficacy and tolerability of topical acne treatments. Here, we describe three case reports in which erythema-directed digital photography was used to evaluate acne before and after up to 12 weeks of treatment with clindamycin 1%/tretinoin 0.025% (Clin-RA). Erythema-directed digital photography was used to evaluate acne in three patients with mild-to-moderate facial acne, two of whom had refused to continue previous topical acne treatment (benzoyl peroxide 5% and clindamycin 1%/benzoyl peroxide 5%) due to persistent irritation. Acne lesions and erythema were evaluated using standard clinical photography and erythema-directed digital photography (VISIA-CR ™ system) before and after 8-12 weeks of treatment with Clin-RA. Erythema-directed digital photography revealed background erythema from previous topical acne treatments that was not evident from standard clinical photographs and allowed a better visualization of both inflammatory and non-inflammatory lesions. In all patients, there was a clear improvement in background erythema and a reduction in acne lesions following treatment with Clin-RA. This study has demonstrated for the first time that erythema-directed digital photography can enhance the evaluation of the efficacy and tolerability of topical acne treatments. These cases show that Clin-RA was associated with improved efficacy and tolerability vs previous treatments with topical monotherapy (benzoyl peroxide 5%) or a topical fixed-dose combination (clindamycin 1%/benzoyl peroxide 5%). © 2018 The Authors. Skin Research and Technology Published by John Wiley & Sons Ltd.

  11. 1,2-diketones promoted degradation of poly(epsilon-caprolactone)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Danko, Martin; Borska, Katarina; Ragab, Sherif Shaban

    2012-07-11

    Photochemical reactions of Benzil and Camphorquinone were used for modification of poly({epsilon}-caprolactone) polymer films. Photochemistry of dopants was followed by infrared spectroscopy, changes on polymer chains of matrix were followed by gel permeation chromatography. Benzoyl peroxide was efficiently photochemically generated from benzyl in solid polymer matrix in the presence of air. Following decomposition of benzoyl peroxide led to degradation of matrix. Photochemical transformation of benzil in vacuum led to hydrogen abstraction from the polymer chains in higher extent, which resulted to chains recombination and formation of gel. Photochemical transformation of camphorquinone to corresponding camphoric peroxide was not observed. Only decreasemore » of molecular weight of polymer matrix doped with camphorquinone was observed during the irradiation.« less

  12. Breaking Benzene Aromaticity-Computational Insights into the Mechanism of the Tungsten-Containing Benzoyl-CoA Reductase.

    PubMed

    Culka, Martin; Huwiler, Simona G; Boll, Matthias; Ullmann, G Matthias

    2017-10-18

    Aromatic compounds are environmental pollutants with toxic and carcinogenic properties. Despite the stability of aromatic rings, bacteria are able to degrade the aromatic compounds into simple metabolites and use them as growth substrates under oxic or even under anoxic conditions. In anaerobic microorganisms, most monocyclic aromatic growth substrates are converted to the central intermediate benzoyl-coenzyme A, which is enzymatically reduced to cyclohexa-1,5-dienoyl-CoA. The strictly anaerobic bacterium Geobacter metallireducens uses the class II benzoyl-CoA reductase complex for this reaction. The catalytic BamB subunit of this complex harbors an active site tungsten-bis-pyranopterin cofactor with the metal being coordinated by five protein/cofactor-derived sulfur atoms and a sixth, so far unknown, ligand. Although BamB has been biochemically and structurally characterized, its mechanism still remains elusive. Here we use continuum electrostatic and QM/MM calculations to model benzoyl-CoA reduction by BamB. We aim to elucidate the identity of the sixth ligand of the active-site tungsten ion together with the interplay of the electron and proton transfer events during the aromatic ring reduction. On the basis of our calculations, we propose that benzoyl-CoA reduction is initiated by a hydrogen atom transfer from a W(IV) species with an aqua ligand, yielding W(V)-[OH - ] and a substrate radical intermediate. In the next step, a proton-assisted second electron transfer takes place with a conserved active-site histidine serving as the second proton donor. Interestingly, our calculations suggest that the electron for the second reduction step is taken from the pyranopterin cofactors rather than from the tungsten ion. The resulting cationic radical, which is distributed over both pyranopterins, is stabilized by conserved anionic amino acid residues. The stepwise mechanism of the reduction shows similarities to the Birch reduction known from organic chemistry. However

  13. Anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) via benzoyl-coenzyme A (CoA) and cyclohex-1-enecarboxyl-CoA in a denitrifying bacterium.

    PubMed Central

    Lochmeyer, C; Koch, J; Fuchs, G

    1992-01-01

    The enzymes catalyzing the initial reactions in the anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) were studied with a denitrifying Pseudomonas sp. anaerobically grown with 2-aminobenzoate and nitrate as the sole carbon and energy sources. Cells grown on 2-aminobenzoate are simultaneously adapted to growth with benzoate, whereas cells grown on benzoate degrade 2-aminobenzoate several times less efficiently than benzoate. Evidence for a new reductive pathway of aromatic metabolism and for four enzymes catalyzing the initial steps is presented. The organism contains 2-aminobenzoate-coenzyme A ligase (2-aminobenzoate-CoA ligase), which forms 2-aminobenzoyl-CoA. 2-Aminobenzoyl-CoA is then reductively deaminated to benzoyl-CoA by an oxygen-sensitive enzyme, 2-aminobenzoyl-CoA reductase (deaminating), which requires a low potential reductant [Ti(III)]. The specific activity is 15 nmol of 2-aminobenzoyl-CoA reduced min-1 mg-1 of protein at an optimal pH of 7. The two enzymes are induced by the substrate under anaerobic conditions only. Benzoyl-CoA is further converted in vitro by reduction with Ti(III) to six products; the same products are formed when benzoyl-CoA or 2-aminobenzoyl-CoA is incubated under reducing conditions. Two of them were identified preliminarily. One product is cyclohex-1-enecarboxyl-CoA, the other is trans-2-hydroxycyclohexane-carboxyl-CoA. The complex transformation of benzoyl-CoA is ascribed to at least two enzymes, benzoyl-CoA reductase (aromatic ring reducing) and cyclohex-1-enecarboxyl-CoA hydratase. The reduction of benzoyl-CoA to alicyclic compounds is catalyzed by extracts from cells grown anaerobically on either 2-aminobenzoate or benzoate at almost the same rate (10 to 15 nmol min-1 mg-1 of protein). In contrast, extracts from cells grown anaerobically on acetate or grown aerobically on benzoate or 2-aminobenzoate are inactive. This suggests a sequential induction of the enzymes. Images PMID:1592816

  14. Anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) via benzoyl-coenzyme A (CoA) and cyclohex-1-enecarboxyl-CoA in a denitrifying bacterium.

    PubMed

    Lochmeyer, C; Koch, J; Fuchs, G

    1992-06-01

    The enzymes catalyzing the initial reactions in the anaerobic degradation of 2-aminobenzoic acid (anthranilic acid) were studied with a denitrifying Pseudomonas sp. anaerobically grown with 2-aminobenzoate and nitrate as the sole carbon and energy sources. Cells grown on 2-aminobenzoate are simultaneously adapted to growth with benzoate, whereas cells grown on benzoate degrade 2-aminobenzoate several times less efficiently than benzoate. Evidence for a new reductive pathway of aromatic metabolism and for four enzymes catalyzing the initial steps is presented. The organism contains 2-aminobenzoate-coenzyme A ligase (2-aminobenzoate-CoA ligase), which forms 2-aminobenzoyl-CoA. 2-Aminobenzoyl-CoA is then reductively deaminated to benzoyl-CoA by an oxygen-sensitive enzyme, 2-aminobenzoyl-CoA reductase (deaminating), which requires a low potential reductant [Ti(III)]. The specific activity is 15 nmol of 2-aminobenzoyl-CoA reduced min-1 mg-1 of protein at an optimal pH of 7. The two enzymes are induced by the substrate under anaerobic conditions only. Benzoyl-CoA is further converted in vitro by reduction with Ti(III) to six products; the same products are formed when benzoyl-CoA or 2-aminobenzoyl-CoA is incubated under reducing conditions. Two of them were identified preliminarily. One product is cyclohex-1-enecarboxyl-CoA, the other is trans-2-hydroxycyclohexane-carboxyl-CoA. The complex transformation of benzoyl-CoA is ascribed to at least two enzymes, benzoyl-CoA reductase (aromatic ring reducing) and cyclohex-1-enecarboxyl-CoA hydratase. The reduction of benzoyl-CoA to alicyclic compounds is catalyzed by extracts from cells grown anaerobically on either 2-aminobenzoate or benzoate at almost the same rate (10 to 15 nmol min-1 mg-1 of protein). In contrast, extracts from cells grown anaerobically on acetate or grown aerobically on benzoate or 2-aminobenzoate are inactive. This suggests a sequential induction of the enzymes.

  15. Ability of m-chloroperoxybenzoic acid to induce the ornithine decarboxylase marker of skin tumor promotion and inhibition of this response by gallotannins, oligomeric proanthocyanidins, and their monomeric units in mouse epidermis in vivo

    Treesearch

    Guilan Chen; Elisabeth M. Perchellet; Xiao Mei Gao; Steven W. Newell; Vittorio Bottari; Richard W. Hemingway; Jean-Pierre Perchellet

    1995-01-01

    m-Chloroperoxybenzoic acid (CPBA) was tested for its ability to induce the ornithine decarboxylase (ODC) marker of skin tumor promotion. In contrast to benzoyl peroxide, dicumyl peroxide, and 2-butanol peroxide, 5 mg of CPBA applied twice at a 72-h interval induce DOC activity at least as much as 3 µg of 12-O-tetradecanoylphorbol-13.acetate (TPA)....

  16. Ability of m-chloroperoxybenzoic acid to induce the ornithine decarboxylase marker of skin tumor promotion and inhibition of this response by gallotannins, oligomeric proanthocyanidins, and their monomeric units in mouse epidermis in Vivo

    Treesearch

    Guilan Chen; Elisabeth M. Perchellet; Xiao Mei Gao; Steven W. Newell; richard W. Hemingway; Vittorio Bottari; Jean-Pierre Perchellet

    1995-01-01

    m-Chloroperoxybenzoic acid (CPBA) was tested for its ability to induce the ornithine decarboxylase (ODC) marker of skin tumor promotion. In contrast to benzoyl peroxide, dicumyl peroxide, and 2-butanol peroxide, 5 mg of CPBA applied twice at a 72-h interval induce ODC activity at least as much as 3 ug of 12-O-tetradecanoylphorbol-13-acetate (TPA). ODC induction peaks...

  17. Structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogues in a microbial antitumor prescreen III: derivatives of p-fluoro-DL-phenylalanine.

    PubMed

    Otani, T T; Briley, M R

    1985-01-01

    Twelve substituted benzoyl derivatives of p-fluoro-DL-phenylalanine were prepared and tested for growth-inhibitory activity in a Lactobacillus casei system used as an antitumor prescreen. The 12 substituted benzoyl groups were the same as those attached to o-fluorophenylalanine and m-fluorophenylalanine studied earlier. The activity of these compounds was compared vertically among themselves and horizontally with the corresponding derivatives of o-fluorophenylalanine and of m-fluorophenylalanine. It was found that the derivatives of p-fluorophenylalanine, like those of o- and m-fluorophenylalanine, exhibited remarkable inhibition, all but one, i.e., the o-nitrobenzoyl derivative, showing inhibition that is considered to be positive in the prescreen. Particularly potent compounds in this group were the m-chlorobenzoyl-, p-chlorobenzoyl, m-nitrobenzoyl, and p-nitrobenzoyl derivatives. Comparison of the activity of the substituted benzoyl derivatives of all three structural isomers of fluorophenylalanine at equimolar concentrations showed that the derivatives of m-fluorophenylalanine were generally better inhibitors than those of o-fluoro- or p-fluorophenylalanine. Study of the ID50 values of the more active substituted benzoyl derivatives of the fluorophenylalanines showed that the most active of this group was m-chlorobenzoyl-p-fluoro-DL-phenylalanine.

  18. The study of structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogs in a microbial antitumor prescreen: II. Derivatives of m-fluoro-DL-phenylalanine.

    PubMed

    Otani, T T; Briley, M R

    1983-05-01

    The fluoro-, chloro-, methoxy- and nitro-substituted benzoyl derivatives of m-fluoro-DL-phenylalanine, substituted singly at the ortho, meta or para position of the benzoyl phenyl ring, were prepared and tested for growth-inhibitory activity in a Lactobacillus casei system used as an antitumor prescreen. The substituted benzoyl derivatives that were previously found to be the most active for o-fluoro-DL-phenylalanine were also the most active for the m-fluoro-DL-phenylalanine. The position of the fluorine substituent in the phenylalanine also appeared to be important for inhibitory activity as the derivatives of m-fluoro-phenylalanine were in general better inhibitors than those of the corresponding o-fluorophenylalanine.

  19. 5-Benzoyl-13-bromo-4-hy­droxy[2.2]paracyclo­phane

    PubMed Central

    Ma, Kelin; Duan, Wenzeng; He, Fuyan; Ma, Yudao

    2012-01-01

    The title compound, C23H19BrO2, was synthesized from 13-bromo-4-hy­droxy[2.2]paracyclo­phane and benzoyl chloride. The hy­droxy and carbonyl groups are involved in intra­molecular O—H⋯O hydrogen bonding. The crystal packing exhibits weak C—H⋯O inter­actions, which link the mol­ecules into sheets parallel to the bc plane. PMID:22590271

  20. Structural, antimicrobial and computational characterization of 1-benzoyl-3-(5-chloro-2-hydroxyphenyl)thiourea.

    PubMed

    Atiş, Murat; Karipcin, Fatma; Sarıboğa, Bahtiyar; Taş, Murat; Çelik, Hasan

    2012-12-01

    A new thiourea derivative, 1-benzoyl-3-(5-chloro-2-hydroxyphenyl)thiourea (bcht) has been synthesized from the reaction of 2-amino-4-chlorophenol with benzoyl isothiocyanate. The title compound has been characterized by elemental analyses, FT-IR, (13)C, (1)H NMR spectroscopy and the single crystal X-ray diffraction analysis. The structure of bcht derived from X-ray diffraction of a single crystal has been presented. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method using 6-311++G(d,p) basis set. The complete assignments of all vibrational modes were performed on the basis of the total energy distributions (TED). Isotropic chemical shifts ((13)C NMR and (1)H NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. Theoretical calculations of bond parameters, harmonic vibration frequencies and nuclear magnetic resonance are in good agreement with experimental results. The UV absorption spectra of the compound that dissolved in ACN and MeOH were recorded. Bcht was also screened for antimicrobial activity against pathogenic bacteria and fungi. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. A phase IV, open-label study evaluating the use of triple-combination therapy with minocycline HCl extended-release tablets, a topical antibiotic/retinoid preparation and benzoyl peroxide in patients with moderate to severe acne vulgaris.

    PubMed

    Zaenglein, Andrea L; Shamban, Ava; Webster, Guy; Del Rosso, James; Dover, Jeffrey S; Swinyer, Leonard; Stein, Linda; Lin, Xiaoming; Draelos, Zoe; Gold, Michael; Thiboutot, Diane

    2013-06-01

    Moderate to severe acne vulgaris is often treated with a combination of an oral antibiotic, topical antibiotic/retinoid, and benzoyl peroxide (BP), but data are limited on the efficacy of this and other combination regimens that incorporate both oral and topical therapies.
    Patients were required to be aged 12-30 years with moderate to severe acne (grades 3-4 acne on the Investigator's Global Assessment [IGA]) and deemed potential candidates for treatment with isotretinoin. Enrolled patients were given triple-combination therapy, defined in this study as oral minocycline HCl extended release 1 mg/kg QD, 6% BP foaming cloths used QD, and clindamycin phosphate 1.2%/tretinoin 0.025% gel applied QD, and were evaluated at baseline and weeks 2, 4, 8, and 12.
    A total of 97 patients were enrolled in the study. At week 12, 89% of patients had at least a one-grade improvement from baseline IGA and 96% had at least a one-grade improvement from baseline Global Aesthetic Improvement Scale score. Mean ± SD in- flammatory, non-inflammatory, and total lesion counts decreased from baseline by 61.8% ± 38.3%, 48.8% ± 34.5%, and 56.5% ± 29.9%, respectively. The percentage of patients evaluated as candidates for isotretinoin by independent photographic review was 77% (69/90) at baseline and only 16% (14/90) at week 12. Treatment-related adverse events (AEs) occurred in eight of 97 (8%) patients. Triplecombination therapy was not associated with any serious AEs or AEs leading to discontinuation.
    Triple-combination therapy was well tolerated and substantially reduced facial acne lesion counts, with 84% of patients judged to no longer be candidates for isotretinoin therapy by study end. These data support the clinical observation that a triple-combination regimen incorporating oral minocycline (dosed by patient weight), BP foaming cloths 6% QD, and clindamycin phosphate 1.2%/ tretinoin 0.025% gel QD can substantially improve moderate to severe acne vulgaris.

  2. A multicentre, randomized, single-blind, parallel-group study comparing the efficacy and tolerability of benzoyl peroxide 3%/clindamycin 1% with azelaic acid 20% in the topical treatment of mild-to-moderate acne vulgaris.

    PubMed

    Schaller, M; Sebastian, M; Ress, C; Seidel, D; Hennig, M

    2016-06-01

    Mild-to-moderate acne vulgaris is treated with a range of mono- and combination therapies; however, clinical evidence is still required to optimize treatment recommendations. To compare the efficacy, tolerability and safety of a combination of benzoyl peroxide 3% and clindamycin 1% (BPO + CLN) with azelaic acid 20% (AzA) for the topical treatment of mild-to-moderate acne vulgaris. This was a randomized, assessor-blinded, parallel-group, multicentre study conducted in Germany. Patients with a confirmed diagnosis of acne vulgaris, aged 12-45 years, were randomized 1 : 1 to once-daily BPO + CLN gel or twice-daily AzA cream for up to 12 weeks. The primary endpoint was the percentage change in inflammatory lesions from baseline at Week 4. Secondary endpoints included total and inflammatory lesion counts and tolerability assessments. For selected secondary endpoints, inductive statistical analysis was performed post hoc. Patient safety was assessed by adverse event (AE) monitoring. Efficacy was assessed in the modified intent-to-treat (mITT) population [patients using ≥1 dose of study medication (ITT), plus baseline and ≥1 post-baseline lesion count (n = 215)]. There was a statistically significant difference in the primary endpoint, with a median decrease of -52.6% for BPO + CLN (n = 107) vs.-38.8% for AzA (n = 108; P = 0.0004). There was also a greater difference in secondary lesion endpoints at Week 12, with a median decrease in inflammatory lesions of -78.8% and -65.3% and total lesions of -69.0% and -53.9% with BPO + CLN and AzA, respectively (both P < 0.0001). Tolerability was acceptable for both treatments. Overall, 55.6% (BPO + CLN) and 69.7% (AzA) of patients reported treatment-emergent AEs, and 15.7% and 35.8% of patients experienced application site reactions with BPO + CLN (24 events; 17 patients) and AzA (60 events; 39 patients) treatment, respectively (ITT population). BPO + CLN demonstrated greater efficacy than AzA in the treatment of mild

  3. Fixed-Dose Combination Gel of Adapalene and Benzoyl Peroxide plus Doxycycline 100 mg versus Oral Isotretinoin for the Treatment of Severe Acne: Efficacy and Cost Analysis.

    PubMed

    Penna, Pete; Meckfessel, Matthew H; Preston, Norman

    2014-01-01

    Acne vulgaris is a chronic skin disease with a high prevalence. Left untreated or inadequately treated, acne vulgaris can lead to psychological and physical scarring, as well as to unnecessary medical expenses. Oral isotretinoin is an effective treatment for severe resistant nodular and conglobate acne vulgaris. A regimen consisting of a fixed-dose combination of adapalene and benzoyl peroxide gel, 0.1%/2.5% (A-BPO) with oral doxycycline 100 mg (A-BPO/D) has been demonstrated to be efficacious and well tolerated in patients with severe acne and may be an alternative to oral isotretinoin for some patients with severe acne. The objective of this analysis was to compare the relative efficacy and associated costs of A-BPO/D versus oral isotretinoin. In this analysis, comparisons of relative efficacy were made using previously published studies involving similar patient populations with severe acne that warrant the use of oral isotretinoin. The pricing for oral doxycycline and oral isotretinoin was estimated based on the maximum allowable cost from 9 states, and the pricing for A-BPO was calculated as the range between the average wholesale price and the wholesale acquisition cost. For this analysis, 2 treatment models were generated to compare costs: (1) a basic treatment model that examined the costs of an initial regimen of either A-BPO/D or oral isotretinoin without considering probable outcomes, and (2) a long-term model that factored in likely treatment outcomes and subsequent treatments into associated costs. The basic treatment model assumed that patients would be prescribed a single regimen of A-BPO/D for 12 weeks or oral isotretinoin for 20 weeks. The long-term model considered the probability of each treatment successfully managing patients' acne, as well as likely additional regimens of A-BPO monotherapy or an additional regimen of oral isotretinoin. As a result of different treatment durations, the costs for each treatment were normalized to weekly cost of

  4. Nitrolysis of the CN Single Bond and Related Chemistry of Nitro and Nitroso Groups.

    DTIC Science & Technology

    1988-03-01

    oxime of be 4,5-diphenyl-l-triphenylmethoxy-l,23- triazole (11). It was benzoyl cyanide (Scheme 6), for which radical intermediates hydrolysed by...S-Pnitroxide (a radical scavenger) or benzoyl peroxide (a radical *PhC CCN)- NO2 Ag PhCON--CPh suc)I I source). A partial extension of the overall...two anomethylenenitronate anion. (Attempts to prepare the pathways for fragmentation of the ester (3) (C,.H,0 N.O,): one ketenimine (15) by a

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

    DOEpatents

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

    2010-11-09

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

  6. Discriminative Dissolution Method for Benzoyl Metronidazole Oral Suspension.

    PubMed

    da Silva, Aline Santos; da Rosa Silva, Carlos Eduardo; Paula, Fávero Reisdorfer; da Silva, Fabiana Ernestina Barcellos

    2016-06-01

    A dissolution method for benzoyl metronidazole (BMZ) oral suspensions was developed and validated using a high-performance liquid chromatography (HPLC) method. After determination of sink conditions, dissolution profiles were evaluated using different dissolution media and agitation speeds. The sample insertion mode in dissolution media was also evaluated. The best conditions were obtained using a paddle, 50 rpm stirring speed, simulated gastric fluid (without pepsin) as the dissolution medium, and sample insertion by a syringe. These conditions were suitable for providing sink conditions and discriminatory power between different formulations. Through the tested conditions, the results can be considered specific, linear, precise, accurate, and robust. The dissolution profiles of five samples were compared using the similarity factor (f 2) and dissolution efficiency. The dissolution kinetics were evaluated and described by the Weibull model. Whereas there is no monograph for this pharmaceutical formulation, the dissolution method proposed can be considered suitable for quality control and dissolution profile comparison of different commercial formulations.

  7. Pilot study of contact sensitization to rubber allergens and bisphenol A amongst dental students.

    PubMed

    Lyapina, Maya Grigorievna; Krasteva, Assya; Dencheva, Maria; Tzekova, Mariana; Nikolov, Georgy; Yaneva-Deliverska, Mariela; Kisselova-Yaneva, Angelina

    2017-05-08

    The aim of this study has been to evaluate the rate of contact sensitization to some rubber allergens and to bisphenol A (BPA) amongst students of dental medicine and dental patients. A total of 50 participants were included in the study: 40 students of dental medicine exposed to the studied rubber allergens and BPA-based dental materials during the course of their education; 10 dental patients without occupational exposure to the latter substances served as a control group. All of them were patch-tested with the studied rubber allergens and bisphenol A. Highest was the sensitizing action of carba mix, followed by benzoyl peroxide and mercapto mix. The sensitization rate for carba mix was significantly higher for dental students as well as for the whole studied population, if compared to the one for thiuram mix (Chi2 = 12.9, p < 0.001; Chi2 = 13.9, p < 0.001), bisphenol A (Chi2 = 8.9, p < 0.001; Chi2 = 11.9, p < 0.001), toluenesulfonamide formaldehyde resin (Chi2 = 10.7, p < 0.001; Chi2 = 13.9, p < 0.001) and benzoyl peroxide (Chi2 = 4.7, p = 0.03; Chi2 = 5.8, p = 0.016), and for dental patients, if compared to the one for mercapto mix (Chi2 = 7.07, p = 0.008). Concomitant positive skin patch-test reactions to carba mix and to benzoyl peroxide, and to all the studied allergens were established. Carba mix could be outlined as a sensitizer of paramount importance for dental students as well as for dental patients. Benzoyl peroxide was the second ranked sensitizer for dental students. Positive skin patch-test reactions to bisphenol A and toluenesulfonamide formaldehyde resin were established only among the group of dental students. Int J Occup Med Environ Health 2017;30(3):397-405. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  8. N-benzoylated 1,4,8,11-tetraazacyclotetradecane and their copper(II) and nickel(II) complexes: Spectral, magnetic, electrochemical, crystal structure, catalytic and antimicrobial studies

    NASA Astrophysics Data System (ADS)

    Nirmala, G.; Rahiman, A. Kalilur; Sreedaran, S.; Jegadeesh, R.; Raaman, N.; Narayanan, V.

    2010-09-01

    A series of N-benzoylated cyclam ligands incorporating three different benzoyl groups 1,4,8,11-tetra-(benzoyl)-1,4,8,11-tetraazacyclotetradecane (L 1), 1,4,8,11-tetra-(2-nitrobenzoyl)-1,4,8,11-tetraazacyclotetradecane (L 2) and 1,4,8,11-tetra-(4-nitrobenzoyl)-1,4,8,11-tetraazacyclotetradecane (L 3) and their nickel(II) and copper(II) complexes are described. Crystal structure of L 1 is also reported. The ligands and complexes were characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectral studies. N-benzoylation causes red shift in the λmax values of the complexes. The cyclic voltammogram of the complexes of ligand L 1 show one-electron, quasi-reversible reduction wave in the region -1.00 to -1.04 V, whereas that of L 2 and L 3 show two quasi-reversible reduction peaks. Nickel complexes show one-electron quasi-reversible oxidation wave at a positive potential in the range +1.05 to +1.15 V. The ESR spectra of the mononuclear copper(II) complexes show four lines, characteristic of square-planar geometry with nuclear hyperfine spin 3/2. All copper(II) complexes show a normal room temperature magnetic moment values μeff 1.70-1.73 BM which is close to the spin-only value of 1.73 BM. Kinetic studies on the oxidation of pyrocatechol to o-quinone using the copper(II) complexes as catalysts and hydrolysis of 4-nitrophenylphosphate using the copper(II) and nickel(II) complexes as catalysts were carried out. All the ligands and their complexes were also screened for antimicrobial activity against Gram-positive, Gram-negative bacteria and human pathogenic fungi.

  9. Copper peroxide

    NASA Technical Reports Server (NTRS)

    Moser, L.

    1988-01-01

    A number of oxidizing agents, including chlorine, bromine, ozone and other peroxides, were allowed to act on copper solutions with the intention of forming copper peroxide. The only successful agent appears to be hydrogen peroxide. It must be used in a neutral 50 to 30 percent solution at a temperature near zero. Other methods described in the literature apparently do not work. The excess of hydrogen must be quickly sucked out of the brown precipitate, which it is best to wash with alcohol and ether. The product, crystalline under a microscope, can be analyzed only approximately. It approaches the formula CuO2H2O. In alkaline solution it appears to act catalytically in causing the decomposition of other peroxides, so that Na2O2 cannot be used to prepare it. On the addition of acids the H2O2 is regenerated. The dry substance decomposes much more slowly than the moist but is not very stable.

  10. Fixed-Dose Combination Gel of Adapalene and Benzoyl Peroxide plus Doxycycline 100 mg versus Oral Isotretinoin for the Treatment of Severe Acne: Efficacy and Cost Analysis

    PubMed Central

    Penna, Pete; Meckfessel, Matthew H.; Preston, Norman

    2014-01-01

    Background Acne vulgaris is a chronic skin disease with a high prevalence. Left untreated or inadequately treated, acne vulgaris can lead to psychological and physical scarring, as well as to unnecessary medical expenses. Oral isotretinoin is an effective treatment for severe resistant nodular and conglobate acne vulgaris. A regimen consisting of a fixed-dose combination of adapalene and benzoyl peroxide gel, 0.1%/2.5% (A-BPO) with oral doxycycline 100 mg (A-BPO/D) has been demonstrated to be efficacious and well tolerated in patients with severe acne and may be an alternative to oral isotretinoin for some patients with severe acne. Objective The objective of this analysis was to compare the relative efficacy and associated costs of A-BPO/D versus oral isotretinoin. Methods In this analysis, comparisons of relative efficacy were made using previously published studies involving similar patient populations with severe acne that warrant the use of oral isotretinoin. The pricing for oral doxycycline and oral isotretinoin was estimated based on the maximum allowable cost from 9 states, and the pricing for A-BPO was calculated as the range between the average wholesale price and the wholesale acquisition cost. For this analysis, 2 treatment models were generated to compare costs: (1) a basic treatment model that examined the costs of an initial regimen of either A-BPO/D or oral isotretinoin without considering probable outcomes, and (2) a long-term model that factored in likely treatment outcomes and subsequent treatments into associated costs. The basic treatment model assumed that patients would be prescribed a single regimen of A-BPO/D for 12 weeks or oral isotretinoin for 20 weeks. The long-term model considered the probability of each treatment successfully managing patients' acne, as well as likely additional regimens of A-BPO monotherapy or an additional regimen of oral isotretinoin. As a result of different treatment durations, the costs for each treatment were

  11. Chem Ed Compacts.

    ERIC Educational Resources Information Center

    Wolf, Walter A., Ed.

    1979-01-01

    Tips are presented for chemistry teachers on the use of acid-base half-reactions in review lessons, the use of calculators by chemistry students, significant figures, and the preparation of benzoyl peroxide from acne medicine. (BB)

  12. Antimicrobial activity of 9-O-acyl- and 9-O-benzoyl-substituted berberrubines.

    PubMed

    Hong, S W; Kim, S H; Jeun, J A; Lee, S J; Kim, S U; Kim, J H

    2000-05-01

    In the course of a structure-activity relationship study on berberrubine derivatives, a series of compounds bearing 9-O-acyl-(4-6) and 9-O-benzoyl- (7) substituents was synthesized with the expectation of increasing the antimicrobial activity. One of the berberrubine derivatives, 9-lauroylberberrubine chloride was the most active against Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Bacillus subtilis as well as the Gram-negative bacterium Klebsiella pneumoniae in comparison to berberine, the currently used antibiotic in clinic. This result suggested that the presence of lipophilic substituents of certain structures and sizes might be crucial for the optimal antimicrobial activity.

  13. Hydrogen peroxide poisoning.

    PubMed

    Watt, Barbara E; Proudfoot, Alex T; Vale, J Allister

    2004-01-01

    Hydrogen peroxide is an oxidising agent that is used in a number of household products, including general-purpose disinfectants, chlorine-free bleaches, fabric stain removers, contact lens disinfectants and hair dyes, and it is a component of some tooth whitening products. In industry, the principal use of hydrogen peroxide is as a bleaching agent in the manufacture of paper and pulp. Hydrogen peroxide has been employed medicinally for wound irrigation and for the sterilisation of ophthalmic and endoscopic instruments. Hydrogen peroxide causes toxicity via three main mechanisms: corrosive damage, oxygen gas formation and lipid peroxidation. Concentrated hydrogen peroxide is caustic and exposure may result in local tissue damage. Ingestion of concentrated (>35%) hydrogen peroxide can also result in the generation of substantial volumes of oxygen. Where the amount of oxygen evolved exceeds its maximum solubility in blood, venous or arterial gas embolism may occur. The mechanism of CNS damage is thought to be arterial gas embolisation with subsequent brain infarction. Rapid generation of oxygen in closed body cavities can also cause mechanical distension and there is potential for the rupture of the hollow viscus secondary to oxygen liberation. In addition, intravascular foaming following absorption can seriously impede right ventricular output and produce complete loss of cardiac output. Hydrogen peroxide can also exert a direct cytotoxic effect via lipid peroxidation. Ingestion of hydrogen peroxide may cause irritation of the gastrointestinal tract with nausea, vomiting, haematemesis and foaming at the mouth; the foam may obstruct the respiratory tract or result in pulmonary aspiration. Painful gastric distension and belching may be caused by the liberation of large volumes of oxygen in the stomach. Blistering of the mucosae and oropharyngeal burns are common following ingestion of concentrated solutions, and laryngospasm and haemorrhagic gastritis have been

  14. Moisturizers for Acne

    PubMed Central

    Chularojanamontri, Leena; Tuchinda, Papapit; Kulthanan, Kanokvalai

    2014-01-01

    Acne is a chronic inflammatory disease of the pilosebaceous unit that affects almost all teenagers. Different treatments offer different modes of action, but aim to target acne pathology. Topical therapies, such as benzoyl peroxide, retinoids, antibiotics with alcohol-based preparations, and salicylic acid, can cause skin irritation resulting in a lack of patient adherence. Some physicians recommend patients use moisturizers as adjunctive treatment of acne, especially when either topical benzoyl peroxide or a retinoid is prescribed. Furthermore, some evidence shows that moisturizers can contribute independently to improve signs and symptoms of acne. Moisturizers contain three main properties, which are occlusive, humectant, and emollient effects. Currently, many moisturizers claim to be suitable for acne treatment. This article aims to provide a review of the active ingredients and properties of those moisturizers. Fifty-two moisturizers for acne were included for analysis. Most of the products (92%) have anti-inflammatory properties apart from occlusive, humectant, and emollient effects. Anti-acne medications, including salicylic acid, benzoyl peroxide, and retinol, were found respectively in 35, 10, and 8 percent of the moisturizer products containing anti-inflammatory properties. More than half of the products contain dimethicone and/or glycerin for its moisturizer property. Aloe vera and witch hazel are botanical anti-inflammatories that were commonly found in this study. Scientific data regarding some ingredients are discussed to provide a guide for physicians in selecting moisturizers for acne patients. PMID:24847408

  15. Crystal structure of 2-benzoyl­amino-N′-(4-hy­droxy­benzyl­idene)-3-(thio­phen-2-yl)prop-2-eno­hydrazide

    PubMed Central

    Subbulakshmi, Karanth N.; Narayana, Badiadka; Yathirajan, Hemmige S.; Jasinski, Jerry P.; Rathore, Ravindranath S.; Glidewell, Christopher

    2016-01-01

    In the title compound, C21H17N3O3S, the non-H atoms, apart from those in the benzoyl group, are almost coplanar (r.m.s. deviation = 0.049 Å) and the benzoyl group is almost orthogonal to the plane of the rest of the mol­ecule [dihedral angle = 80.34 (6)°]. In the crystal, a combination of N—H⋯O and asymmetric bifurcated O—H⋯(N,O) hydrogen bonds link the mol­ecules into a three-dimensional network. Weak C—H⋯O inter­actions are also observed. PMID:27536390

  16. PRECIPITATION OF PLUTONOUS PEROXIDE

    DOEpatents

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

    1961-08-15

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

  17. Prevention and Reduction of Atrophic Acne Scars with Adapalene 0.3%/Benzoyl Peroxide 2.5% Gel in Subjects with Moderate or Severe Facial Acne: Results of a 6-Month Randomized, Vehicle-Controlled Trial Using Intra-Individual Comparison.

    PubMed

    Dréno, Brigitte; Bissonnette, Robert; Gagné-Henley, Angélique; Barankin, Benjamin; Lynde, Charles; Kerrouche, Nabil; Tan, Jerry

    2018-04-01

    Very few clinical trials have investigated the effect of topical acne treatment on scarring. Our objective was to evaluate the efficacy of adapalene 0.3%/benzoyl peroxide 2.5% gel (A0.3/BPO2.5) in atrophic acne scar formation in patients with acne. In this multicenter, randomized, investigator-blinded, vehicle-controlled study, subjects with moderate or severe facial acne (Investigator's Global Assessment [IGA] score 3 or 4; ≥ 25 inflammatory lesions; ten or more atrophic acne scars) applied A0.3/BPO2.5 or vehicle daily per half face for 24 weeks. Subjects with acne requiring systemic treatment were excluded. Assessments included investigator atrophic acne scar count, Scar Global Assessment (SGA), acne lesion count, IGA, skin roughness and skin texture, subject self-assessment of clinical acne-related scars and satisfaction questionnaire, tolerability, and safety. Included subjects (n = 67) had mainly moderate acne (92.5% IGA 3); mean scores at baseline were approximately 40 acne lesions and 12 scars per half face. By week 24, the change from baseline in total scar count was - 15.5% for A0.3/BPO2.5 versus  + 14.4% for vehicle (approximately 30% difference), with a mean of 9.5 scars versus 13.3 per half face, respectively (p < 0.0001). For SGA at week 24, a total of 32.9% with A0.3/BPO2.5 versus 16.4% with vehicle (p < 0.01) were clear/almost clear. Inflammatory acne lesions decreased by 86.7% for A0.3/BPO2.5 versus 57.9% for vehicle (p < 0.0001), and 64.2 versus 19.4% of subjects, respectively, were IGA clear/almost clear (p < 0.0001) at week 24. Treatment-related AEs were reported by 20.9% for A0.3/BPO2.5 versus 9% for vehicle side, most commonly skin irritation (14.9 vs. 6%, respectively). Topical A0.3/BPO2.5 prevented and reduced atrophic scar formation. Scar count increased with vehicle (+ 14.4%) but decreased with A0.3/BPO2.5 (- 15.5%) over 24 weeks. ClinicalTrials.gov identifier NCT02735421.

  18. Hydrogen peroxide kinetics in water radiolysis

    NASA Astrophysics Data System (ADS)

    Iwamatsu, Kazuhiro; Sundin, Sara; LaVerne, Jay A.

    2018-04-01

    The kinetics of the formation and reaction of hydrogen peroxide in the long time γ- radiolysis of water is examined using a combination of experiment with model calculations. Escape yields of hydrogen peroxide on the microsecond time scale are easily measured with added radical scavengers even with substantial amounts of initial added hydrogen peroxide. The γ-radiolysis of aqueous hydrogen peroxide solutions without added radical scavengers reach a steady state limiting concentration of hydrogen peroxide with increasing dose, and that limit is directly proportional to the initial concentration of added hydrogen peroxide. The dose necessary to reach that limiting hydrogen peroxide concentration is also proportional to the initial concentration, but dose rate has a very small effect. The addition of molecular hydrogen to aqueous solutions of hydrogen peroxide leads to a decrease in the high dose limiting hydrogen peroxide concentration that is linear with the initial hydrogen concentration, but the amount of decrease is not stoichiometric. Proton irradiations of solutions with added hydrogen peroxide and hydrogen are more difficult to predict because of the decreased yields of radicals; however, with a substantial increase in dose rate there is a sufficient decrease in radical yields that hydrogen addition has little effect on hydrogen peroxide decay.

  19. The "Mushroom Cloud" Demonstration Revisited

    ERIC Educational Resources Information Center

    Panzarasa, Guido; Sparnacci, Katia

    2013-01-01

    A revisitation of the classical "mushroom cloud" demonstration is described. Instead of aniline and benzoyl peroxide, the proposed reaction involves household chemicals such as alpha-pinene (turpentine oil) and trichloroisocyanuric acid ("Trichlor") giving an impressive demonstration of oxidation and combustion reactions that…

  20. 1-(1,3-Benzothia­zol-2-yl)-3-benzoyl­thio­urea

    PubMed Central

    Yunus, Uzma; Tahir, Muhammad Kalim; Bhatti, Moazzam Hussain; Ali, Saqib; Wong, Wai-Yeung

    2008-01-01

    The title compound, C15H11N3OS2, was synthesized from benzoyl thio­cyanate and 2-amino­benzothia­zole in dry acetone. The thio­urea group is in the thio­amide form. The mol­ecules are stabilized by two inter­molecular C—H⋯S and C—H⋯O hydrogen bonds. Intra­molecular N—H⋯O hydrogen bonding results in a pseudo-S(6) planar ring with dihedral angles of 11.23 and 11.91° with the benzothiazole ring system and the phenyl ring, respectively. PMID:21200765

  1. Topical Vehicle Formulations in the Treatment of Acne.

    PubMed

    Hoffman, Lauren K; Bhatia, Neal; Zeichner, Joshua; Kircik, Leon H

    2018-06-01

    Topical treatment is the mainstay of acne therapy. The most commonly prescribed topical medications for acne include benzoyl peroxide, clindamycin, and retinoids. Despite their effectiveness in treating mild to moderate acne vulgaris, these topical medications are found to be irritating, and are historically associated with poor tolerability and diminished patient adherence. Thus, choosing the right formulation that will be effective and well tolerated is essential. Novel formulations that optimize drug concentration and utilize improved delivery vehicles have helped to enhance the tolerability and efficacy, and allow for less frequent application or co-application of drugs that were previously considered incompatible. This article will review the goals of topical therapy for the treatment of acne, in addition to common therapies and their challenges. Advanced formulations and combination formulations of benzoyl peroxide, clindamycin, and tretinoin will also be discussed. J Drugs Dermatol. 2018;17(6 Suppl):s6-10.

  2. Management strategies for acne vulgaris

    PubMed Central

    Whitney, Kristen M; Ditre, Chérie M

    2011-01-01

    Clinical question: What are the most effective treatment(s) for mild, moderate, severe, and hormonally driven acne? Results: Mild acne responds favorably to topical treatments such as benzoyl peroxide, salicylic acid, and a low-dose retinoid. Moderate acne responds well to combination therapy comprising-topical benzoyl peroxide, antibiotics, and/or retinoids, as well as oral antibiotics in refractory cases and oral contraceptive pills for female acne patients. Severe nodulocystic acne vulgaris responds best to oral isotretinoin therapy. In female patients with moderate to severe acne, facial hair, loss of scalp hair and irregular periods, polycystic ovarian syndrome should be considered and appropriate treatment with hormonal modulation given. Adjunctive procedures can also be considered for all acne patients. Implementation: Pitfalls to avoid when treating acne: treatment of acne in women of child-bearing age; familiarization of all acne treatments in order to individualize management for patients; indications for specialist referral. PMID:21691566

  3. On copper peroxide

    NASA Technical Reports Server (NTRS)

    Moser, L.

    1988-01-01

    The action of hydrogen superoxide on copper salts in alcoholic solutions is studied. The action of hydrogen peroxide on copper hydroxide in alcoholic suspensions, and the action of ethereal hydrogen peroxide on copper hydroxide are discussed. It is concluded that using the procedure proposed excludes almost entirely the harmful effect of hydrolysis.

  4. 76 FR 36307 - Guidance for Industry on Topical Acne Drug Products for Over-the-Counter Human Use-Revision of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... the monograph (75 FR 9767, March 4, 2010) (final rule). The guidance describes the requirements of the... products marketed under the monograph (i.e., products that contain any of the active ingredients permitted under the OTC topical acne drug monograph, including benzoyl peroxide, resorcinol, resorcinol...

  5. Influence of Bleaching on Flavor of 34% Whey Protein Concentrate and Residual Benzoic Acid Concentration in Dried Whey Proteins

    USDA-ARS?s Scientific Manuscript database

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  6. Influence of bleaching on flavor of 34% whey protein concentrate and residual benzoic acid concentration in dried whey products

    USDA-ARS?s Scientific Manuscript database

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  7. Chemistry of peroxide compounds

    NASA Technical Reports Server (NTRS)

    Volnov, I. I.

    1981-01-01

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

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

    PubMed

    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 O 2 -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 O 2 , 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. Benzoyl radicals from (hetero)aromatic aldehydes. Decatungstate photocatalyzed synthesis of substituted aromatic ketones.

    PubMed

    Ravelli, Davide; Zema, Michele; Mella, Mariella; Fagnoni, Maurizio; Albini, Angelo

    2010-09-21

    Benzoyl radicals are generated directly from (hetero)aromatic aldehydes upon tetrabutylammonium decatungstate ((n-Bu(4)N)(4)W(10)O(32)), TBADT) photocatalysis under mild conditions. In the presence of alpha,beta-unsaturated esters, ketones and nitriles radical conjugate addition ensues and gives the corresponding beta-functionalized aryl alkyl ketones in moderate to good yields (stereoselectively in the case of 3-methylene-2-norbornanone). Due to the mild reaction conditions the presence of various functional groups on the aromatic ring is tolerated (e.g. methyl, methoxy, chloro). The method can be applied to hetero-aromatic aldehydes whether electron-rich (e.g. thiophene-2-carbaldehyde) or electron-poor (e.g. pyridine-3-carbaldehyde).

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

    PubMed

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

    2013-05-01

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

  11. Ocular response to hydrogen peroxide.

    PubMed

    Paugh, J R; Brennan, N A; Efron, N

    1988-02-01

    A controlled, randomized, double-masked study was conducted on eight human subjects to determine the threshold level of hydrogen peroxide, which is toxic when introduced into the eye via a high water content (75%; Durasoft 4) hydrogel contact lens. Subjective comfort, conjunctival hyperemia, corneal and conjunctival epithelial staining, and corneal oxygen uptake were assessed in response to 5-min wear of lenses that were presoaked in isotonic saline solutions of physiologic pH containing 0, 25, 50, 100, 200, 400, and 800 parts per million (ppm) hydrogen peroxide. Higher levels of hydrogen peroxide were associated with greater discomfort (p less than 0.05) and increased conjunctival hyperemia (p less than 0.001). The highest level of hydrogen peroxide tested (800 ppm) did not induce significant corneal or conjunctival epithelial staining or alter the corneal aerobic response. We conclude that residual concentrations of hydrogen peroxide in contact lens care systems should not exceed 100 ppm. Practitioners can use these data to estimate the level of residual hydrogen peroxide to which a patient may have been exposed upon lens application after neutralization.

  12. Structure and Function of the Unusual Tungsten Enzymes Acetylene Hydratase and Class II Benzoyl-Coenzyme A Reductase.

    PubMed

    Boll, Matthias; Einsle, Oliver; Ermler, Ulrich; Kroneck, Peter M H; Ullmann, G Matthias

    2016-01-01

    In biology, tungsten (W) is exclusively found in microbial enzymes bound to a bis-pyranopterin cofactor (bis-WPT). Previously known W enzymes catalyze redox oxo/hydroxyl transfer reactions by directly coordinating their substrates or products to the metal. They comprise the W-containing formate/formylmethanofuran dehydrogenases belonging to the dimethyl sulfoxide reductase (DMSOR) family and the aldehyde:ferredoxin oxidoreductase (AOR) families, which form a separate enzyme family within the Mo/W enzymes. In the last decade, initial insights into the structure and function of two unprecedented W enzymes were obtained: the acetaldehyde forming acetylene hydratase (ACH) belongs to the DMSOR and the class II benzoyl-coenzyme A (CoA) reductase (BCR) to the AOR family. The latter catalyzes the reductive dearomatization of benzoyl-CoA to a cyclic diene. Both are key enzymes in the degradation of acetylene (ACH) or aromatic compounds (BCR) in strictly anaerobic bacteria. They are unusual in either catalyzing a nonredox reaction (ACH) or a redox reaction without coordinating the substrate or product to the metal (BCR). In organic chemical synthesis, analogous reactions require totally nonphysiological conditions depending on Hg2+ (acetylene hydration) or alkali metals (benzene ring reduction). The structural insights obtained pave the way for biological or biomimetic approaches to basic reactions in organic chemistry. © 2016 S. Karger AG, Basel.

  13. Electrochemical Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    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

  14. The Peroxide Pathway

    NASA Technical Reports Server (NTRS)

    McNeal, Curtis I., Jr.; Anderson, William

    1999-01-01

    NASA's current focus on technology roadmaps as a tool for guiding investment decisions leads naturally to a discussion of NASA's roadmap for peroxide propulsion system development. NASA's new Second Generation Space Transportation System roadmap calls for an integrated Reusable Upper-Stage (RUS) engine technology demonstration in the FY03/FY04 time period. Preceding this integrated demonstration are several years of component developments and subsystem technology demonstrations. NASA and the Air Force took the first steps at developing focused upper stage technologies with the initiation of the Upper Stage Flight Experiment with Orbital Sciences in December 1997. A review of this program's peroxide propulsion development is a useful first step in establishing the peroxide propulsion pathway that could lead to a RUS demonstration in 2004.

  15. Detection of hydrogen peroxide with graphyne

    NASA Astrophysics Data System (ADS)

    Majidi, R.; Karami, A. R.

    2013-12-01

    The effect of hydrogen peroxide on the electronic properties of graphyne has been investigated to explore the possibility of using graphyne based biosensor. We have used density functional theory to study the electronic properties of γ-graphyne in the presence of different number of hydrogen peroxide. The optimal adsorption position, orientation, and distance of hydrogen peroxide adsorbed on the graphyne sheet have been determined by calculating adsorption energy. It is found that γ-graphyne which is an intrinsic semiconductor becomes an n-type semiconductor due to the presence of hydrogen peroxide. The energy band gap of γ-graphyne is decreased by increasing the number of hydrogen peroxide. The results demonstrate that γ-graphyne is a promising candidate for biosensor application because of its electrical sensitivity to hydrogen peroxide.

  16. High temperature concrete composites containing organosiloxane crosslinked copolymers

    DOEpatents

    Zeldin, A.; Carciello, N.; Kukacka, L.; Fontana, J.

    High temperature polymer concrete composites comprising about 10 to 30% by weight of a liquid monomer mixture is described. It consists essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures thereof. About 70 to 90% by weight of an inert inorganic filler system containing silica sand and portland cement, Fe/sub 2/O/sub 3/, carbon black or mixtures thereof. Optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobyutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides are used to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

  17. High-performance liquid chromatography with peroxyoxalate chemiluminescence detection of bisphenol A migrated from polycarbonate baby bottles using 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride as a label.

    PubMed

    Sun, Y; Wada, M; Al-Dirbashi, O; Kuroda, N; Nakazawa, H; Nakashima, K

    2000-11-10

    A highly sensitive and selective high-performance liquid chromatographic method with peroxyoxalate chemiluminescence detection for the determination of bisphenol A at sub-ppb levels is described. Bisphenol A was derivatized with 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride and the excess unreacted reagent was removed by a simple solid-phase extraction procedure with recoveries of approximately 60%. The separation was carried out isocratically on an ODS column and the derivatized bisphenol A was detected by peroxyoxalate chemiluminescence. A mixture of bis[2-(3,6,9-trioxadecanyloxycarbonyl)-4-nitrophenyl]oxalate (0.6 mM) and hydrogen peroxide (25.0 mM) dissolved in acetonitrile was used as a chemiluminescence reagent solution with a mixture of imidazole-HNO3 buffer (40.0 mM, pH 7.0): acetonitrile (17:83, v/v) as a mobile phase. The linear standard curve was obtained over the range from 0.57 (2.5) to 22.8 (100) ppb (nM) (r=0.996) with a detection limit of 0.38 ppb (2.8 fmol on column) at a signal-to-noise ratio of 3. The method was successfully applied to the determination of bisphenol A in hot water in contact with commercially available baby bottle samples.

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

    ERIC Educational Resources Information Center

    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…

  19. Purification of circular DNA using benzoylated naphthoylated DEAE-cellulose.

    PubMed

    Gamper, H; Lehman, N; Piette, J; Hearst, J E

    1985-04-01

    Un-nicked circular DNA can be separated from protein, RNA, and other DNA in a simple three-step protocol consisting of exonuclease III digestion, extraction with benzoylated naphthoylated DEAE-cellulose (BND cellulose) in 1 M NaCl, and alcohol precipitation of the remaining supercoiled DNA. Exonuclease III treatment introduces single-stranded regions into contaminating linear and nicked circular DNA. This DNA, together with most RNA and protein, is adsorbed onto BND cellulose leaving form I DNA in solution. The protocol can be used to purify analytical as well as preparative amounts of supercoiled DNA. This procedure is a substitute for cesium chloride-ethidium bromide gradient ultracentrifugation and gives a comparable yield of pure form I DNA. Other classes of DNA can be isolated by changing the pretreatment step. Selective digestion of linear DNA with lambda exonuclease permits the isolation of both nicked circular and supercoiled DNA while brief heat-induced or alkali-induced denaturation leads to the recovery of rapidly reannealing DNA. In large-scale purifications, the basic protocol is usually preceded by one or more BND cellulose extractions in 1 M NaCl to remove contaminants absorbing UV or inhibiting exonuclease III.

  20. Characterisation of a LoVo subline resistant to a benzoyl mustard derivative of distamycin A (FCE 24517).

    PubMed Central

    Capolongo, L.; Melegaro, G.; Broggini, M.; Mongelli, N.; Grandi, M.

    1993-01-01

    Human colon adenocarcinoma cells (LoVo) resistant to the new antitumor agent FCE 24517 [benzoyl-mustard derivative of distamycin A] (LoVo/24517) are resistant to the selecting agent and related molecules as well as to vinblastine, with marginal or no resistance to other antitumour drugs. Treatment with verapamil, tamoxifen, nicergoline or cyclosporin A only partially restores the activity of FCE 24517 against LoVo/24517 cells. Such results suggest that resistance mechanisms possible specific for this class of compounds are operating. Images Figure 2 PMID:8105866

  1. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Hydrogen peroxide solution. 178.1005 Section 178... Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in...)(1) of this section. (a) Identity. For the purpose of this section, hydrogen peroxide solution is an...

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

    NASA Technical Reports Server (NTRS)

    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)-.

  3. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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) [Reserved] (c) Limitations...

  4. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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) [Reserved] (c) Limitations...

  5. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    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) [Reserved] (c) Limitations...

  6. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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) [Reserved] (c) Limitations...

  7. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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) [Reserved] (c) Limitations...

  8. Coating for components requiring hydrogen peroxide compatibility

    NASA Technical Reports Server (NTRS)

    Yousefiani, Ali (Inventor)

    2010-01-01

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

  9. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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 peroxide...

  10. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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 peroxide...

  11. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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 peroxide...

  12. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    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 peroxide...

  13. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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 peroxide...

  14. Interaction of N-benzoyl-D-phenylalanine and related compounds with the sulphonylurea receptor of beta-cells.

    PubMed

    Schwanstecher, C; Meyer, M; Schwanstecher, M; Panten, U

    1998-03-01

    1. The structure activity relationships for the insulin secretagogues N-benzoyl-D-phenylalanine (NBDP) and related compounds were examined at the sulphonylurea receptor level by use of cultured HIT-T15 and mouse pancreatic beta-cells. The affinities of these compounds for the sulphonylurea receptor were compared with their potencies for K(ATP)-channel inhibition. In addition, the effects of cytosolic nucleotides on K(ATP)-channel inhibition by NBDP were investigated. 2. NBDP displayed a dissociation constant for binding to the sulphonylurea receptor (K(D) value) of 11 microM and half-maximally effective concentrations of K(ATP)-channel inhibition (EC50 values) between 2 and 4 microM (in the absence of cytosolic nucleotides or presence of 0.1 mM GDP or 1 mM ADP). 3. In the absence of cytosolic nucleotides or presence of GDP (0.1 mM) maximally effective concentrations of NBDP (0.1-1 mM) reduced K(ATP)-channel activity to 47% and 44% of control, respectively. In the presence of ADP (1 mM), K(ATP)-channel activity was completely suppressed by 0.1 mM NBDP. 4. The L-isomer of N-benzoyl-phenylalanine displayed a 20 fold lower affinity and an 80 fold lower potency than the D-isomer. 5. Introduction of a p-nitro substituent in the D-phenylalanine moiety of NBDP did not decrease lipophilicity but lowered affinity and potency by more than 30 fold. 6. Introduction of a p-amino substituent in the D-phenylalanine moiety of NBDP (N-benzoyl-p-amino-D-phenylalanine, NBADP) reduced lipophilicity and lowered affinity and potency by about 10 fold. This loss of affinity and potency was compensated for by formation of the phenylpropionic acid derivative of NBADP. A similar difference in affinity was observed for the sulphonylurea carbutamide and its phenylpropionic acid derivative. 7. Replacing the benzene ring in the D-phenylalanine moiety of NBDP by a cyclohexyl ring increased lipophilicity, and the K(D) and EC50 values were slightly lower than for NBDP. Exchange of both benzene rings

  15. Interaction of N-benzoyl-D-phenylalanine and related compounds with the sulphonylurea receptor of β-cells

    PubMed Central

    Schwanstecher, Christina; Meyer, Miriam; Schwanstecher, Mathias; Panten, Uwe

    1998-01-01

    The structure activity relationships for the insulin secretagogues N-benzoyl-D-phenylalanine (NBDP) and related compounds were examined at the sulphonylurea receptor level by use of cultured HIT-T15 and mouse pancreatic β-cells. The affinities of these compounds for the sulphonylurea receptor were compared with their potencies for KATP-channel inhibition. In addition, the effects of cytosolic nucleotides on KATP-channel inhibition by NBDP were investigated.NBDP displayed a dissociation constant for binding to the sulphonylurea receptor (KD value) of 11 μM and half-maximally effective concentrations of KATP-channel inhibition (EC50 values) between 2 and 4 μM (in the absence of cytosolic nucleotides or presence of 0.1 mM GDP or 1 mM ADP).In the absence of cytosolic nucleotides or presence of GDP (0.1 mM) maximally effective concentrations of NBDP (0.1–1 mM) reduced KATP-channel activity to 47% and 44% of control, respectively. In the presence of ADP (1 mM), KATP-channel activity was completely suppressed by 0.1 mM NBDP.The L-isomer of N-benzoyl-phenylalanine displayed a 20 fold lower affinity and an 80 fold lower potency than the D-isomer.Introduction of a p-nitro substituent in the D-phenylalanine moiety of NBDP did not decrease lipophilicity but lowered affinity and potency by more than 30 fold.Introduction of a p-amino substituent in the D-phenylalanine moiety of NBDP (N-benzoyl-p-amino-D-phenylalanine, NBADP) reduced lipophilicity and lowered affinity and potency by about 10 fold. This loss of affinity and potency was compensated for by formation of the phenylpropionic acid derivative of NBADP. A similar difference in affinity was observed for the sulphonylurea carbutamide and its phenylpropionic acid derivative.Replacing the benzene ring in the D-phenylalanine moiety of NBDP by a cyclohexyl ring increased lipophilicity, and the KD and EC50 values were slightly lower than for NBDP. Exchange of both benzene rings in NBDP by cyclohexyl rings

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

    PubMed Central

    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

  17. Detection of hydrogen peroxide with chemiluminescent micelles

    PubMed Central

    Lee, Dongwon; Erigala, Venkata R; Dasari, Madhuri; Yu, Junhua; Dickson, Robert M; Murthy, Niren

    2008-01-01

    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. PMID:19337415

  18. 21 CFR 184.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Hydrogen peroxide. 184.1366 Section 184.1366 Food... Specific Substances Affirmed as GRAS § 184.1366 Hydrogen peroxide. (a) Hydrogen peroxide (H2O2, CAS Reg. No. 7722-84-1) is also referred to as hydrogen dioxide. It is made by the electrolytic oxidation of...

  19. 21 CFR 184.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Hydrogen peroxide. 184.1366 Section 184.1366 Food... Specific Substances Affirmed as GRAS § 184.1366 Hydrogen peroxide. (a) Hydrogen peroxide (H2O2, CAS Reg. No. 7722-84-1) is also referred to as hydrogen dioxide. It is made by the electrolytic oxidation of...

  20. 21 CFR 184.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Hydrogen peroxide. 184.1366 Section 184.1366 Food... Specific Substances Affirmed as GRAS § 184.1366 Hydrogen peroxide. (a) Hydrogen peroxide (H2O2, CAS Reg. No. 7722-84-1) is also referred to as hydrogen dioxide. It is made by the electrolytic oxidation of...

  1. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be....C. 552(a) and 1 CFR part 51. You may obtain copies from the United States Pharmacopeial Convention...

  2. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be....C. 552(a) and 1 CFR part 51. You may obtain copies from the United States Pharmacopeial Convention...

  3. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be....C. 552(a) and 1 CFR part 51. You may obtain copies from the United States Pharmacopeial Convention...

  4. Thermomechanical pulp fiber surface modification for enhancing the interfacial adhesion with polypropylene

    Treesearch

    Sangyeob Lee; Todd F. Shupe; Leslie H. Groom; Chung Y. Hse

    2007-01-01

    Chemical coupling on the thermomechanical pulp (TMP) fiber improved tensile strength of the TMP fiber handsheet and isotactic polypropylene film laminates (TPL). For the maleic anhydride W) with benzoyl peroxide (BPO)a an initiator, tensile strength increaded 52: with the TMP fiber treatment over untreated laminates. The optimum strength properties were obtained with...

  5. High temperature concrete composites containing organosiloxane crosslinked copolymers

    DOEpatents

    Zeldin, Arkady; Carciello, Neal; Kukacka, Lawrence; Fontana, Jack

    1980-01-01

    This invention relates to high temperature polymer concrete composites comprising about 10-30% by weight of a liquid monomer mixture consisting essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures theroef; and about 70-90% by weight of an inert inorganic filler system containing silica sand and preferably a member selected from the group consisting of portland cement, Fe.sub.2 O.sub.3, carbon black and mixtures thereof; and optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

  6. Efficacy, efficiency and safety aspects of hydrogen peroxide vapour and aerosolized hydrogen peroxide room disinfection systems.

    PubMed

    Fu, T Y; Gent, P; Kumar, V

    2012-03-01

    This was a head-to-head comparison of two hydrogen-peroxide-based room decontamination systems. To compare the efficacy, efficiency and safety of hydrogen peroxide vapour (HPV; Clarus R, Bioquell, Andover, U.K.) and aerosolized hydrogen peroxide (aHP; SR2, Sterinis, now supplied as Glosair, Advanced Sterilization Products (ASP), Johnson & Johnson Medical Ltd, Wokingham, U.K.) room disinfection systems. Efficacy was tested using 4- and 6-log Geobacillus stearothermophilus biological indicators (BIs) and in-house prepared test discs containing approximately 10(6) meticillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile and Acinetobacter baumannii. Safety was assessed by detecting leakage of hydrogen peroxide using a hand-held detector. Efficiency was assessed by measuring the level of hydrogen peroxide using a hand-held sensor at three locations inside the room, 2 h after the start of the cycles. HPV generally achieved a 6-log reduction, whereas aHP generally achieved less than a 4-log reduction on the BIs and in-house prepared test discs. Uneven distribution was evident for the aHP system but not the HPV system. Hydrogen peroxide leakage during aHP cycles with the door unsealed, as per the manufacturer's operating manual, exceeded the short-term exposure limit (2 ppm) for more than 2 h. When the door was sealed with tape, as per the HPV system, hydrogen peroxide leakage was <1 ppm for both systems. The mean concentration of hydrogen peroxide in the room 2 h after the cycle started was 1.3 [standard deviation (SD) 0.4] ppm and 2.8 (SD 0.8) ppm for the four HPV and aHP cycles, respectively. None of the readings were <2 ppm for the aHP cycles. The HPV system was safer, faster and more effective for biological inactivation. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  7. 21 CFR 184.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Hydrogen peroxide. 184.1366 Section 184.1366 Food... GRAS § 184.1366 Hydrogen peroxide. (a) Hydrogen peroxide (H2O2, CAS Reg. No. 7722-84-1) is also referred to as hydrogen dioxide. It is made by the electrolytic oxidation of sulfuric acid or a sulfate to...

  8. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be safely used to treat food in accordance with... approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You may...

  9. Hydrogen peroxide stabilization in one-dimensional flow columns

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  10. Effects of silane on the properties of wood-plastic composites with polyethylene-polypropylene blends as matrices

    Treesearch

    Craig M. Clemons; Ronald C. Sabo; Michael L. Kaland; Kolby C. Hirth

    2011-01-01

    The influence of 3-(trimethoxysilyl)propyl methacrylate and benzoyl peroxide on gel content, crystallinity, and mechanical performance of unfilled PP-PE blends, and their composites with wood was investigated. All materials were compounded in a twin screw extruder and then injection molded. Specimens were then exposed to high-humidity and elevated temperature in a...

  11. Maleated polypropylene film and wood fiber handsheet laminates

    Treesearch

    Sangyeob Lee; Todd F. Shupe; Leslie H. Groom; Chung Y. Hse

    2008-01-01

    The grafting effect of maleic anhydride (MA) as an interfacial bonding agent and its influence on the tensile strength properties of thermomechanical pulp handsheet-isotactic polypropylene (iPP) film laminates was studied. For the MA treated with benzoyl peroxide (BPO) as an initiator, tensile strength properties increased 76% with PP film over untreated laminates. The...

  12. Rearrangements of organic peroxides and related processes

    PubMed Central

    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

  13. Hydrogen peroxide stabilization in one-dimensional flow columns.

    PubMed

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

    2011-09-25

    Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H(2)O(2) propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO. Copyright © 2011. Published by Elsevier B.V.

  14. A double-blind investigation of the potential systemic absorption of isotretinoin, when combined with chemical sunscreens, following topical application to patients with widespread acne of the face and trunk.

    PubMed

    Cunliffe, W J; Glass, D; Goode, K; Stables, G I; Boorman, G C

    2001-01-01

    This study assessed the systemic absorption of isotretinoin and its metabolites, during a 4-week application of a cream containing 0.1% isotretinoin and chemical sunscreens, compared with a 4% benzoyl peroxide cream, in patients with acne on the face and trunk. Blood was drawn at weeks 0, 1, 2, 3 and 4 and at 96 h post-treatment. Plasma levels of isotretinoin (13-cis-retinoic acid) and tretinoin (all-trans-retinoic acid) were quantified by liquid chromatography with tandem mass spectrometry and the presence of their combined 4-oxo metabolites were monitored from the peak area ratios observed. The isotretinoin group showed no statistically or clinically significant increases in plasma retinoid levels and mean levels did not exceed +/-2 SD of the mean pre-treatment values, indicating that endogenous levels were not being exceeded. No significant differences were detected between the isotretinoin group and the 4% benzoyl peroxide group. These findings indicated that retinoid absorption from a cream containing 0.1% isotretinoin and chemical sunscreens was clinically insignificant, when applied to patients with widespread acne.

  15. Chemiluminescence of Organic Peroxides. Thermal Generation of an o-Xylylene Peroxide.

    DTIC Science & Technology

    1981-04-07

    Iq It. KEY WORDS (Countinue oni tow.e* ole At neesar did tffoiltl by *lack Mmber) ?T. chemil uminesceflce AR~~ 1 * peroxides A CIEEL therniol1ys is b...recrystallization of the result- ing residue gives a peroxidic white solid. The structure of this material was deduced from spectroscopic, osmometric...recrystallized from pentane-CH2Cl to 22 give j 36 mg (32%,) as a white solid, m.p. 1.090 (with decomposition). 1HNMR (CDC]3): 7.0-6.8 (d, 2H1); 7.9-7.2

  16. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric food...

  17. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric food...

  18. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Hydrogen peroxide solution. 178.1005 Section 178... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution. Hydrogen peroxide solution identified in this section may be safely used to sterilize polymeric food...

  19. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  20. Isothermal Decomposition of Hydrogen Peroxide Dihydrate

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  1. Kinetics of Platinum-Catalyzed Decomposition of Hydrogen Peroxide

    NASA Astrophysics Data System (ADS)

    Vetter, Tiffany A.; Colombo, D. Philip, Jr.

    2003-07-01

    CIBA Vision Corporation markets a contact lens cleaning system that consists of an AOSEPT disinfectant solution and an AOSEPT lens cup. The disinfectant is a buffered 3.0% m/v hydrogen peroxide solution and the cup includes a platinum-coated AOSEPT disc. The hydrogen peroxide disinfects by killing bacteria, fungi, and viruses found on the contact lenses. Because the concentration of hydrogen peroxide needed to disinfect is irritating to eyes, the hydrogen peroxide needs to be neutralized, or decomposed, before the contact lenses can be used again. A general chemistry experiment is described where the kinetics of the catalyzed decomposition of the hydrogen peroxide are studied by measuring the amount of oxygen generated as a function of time. The order of the reaction with respect to the hydrogen peroxide, the rate constant, and the energy of activation are determined. The integrated rate law is used to determine the time required to decompose the hydrogen peroxide to a concentration that is safe for eyes.

  2. High temperature chemically resistant polymer concrete

    DOEpatents

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  3. Hydrogen Peroxide Probes Directed to Different Cellular Compartments

    PubMed Central

    Malinouski, Mikalai; Zhou, You; Belousov, Vsevolod V.; Hatfield, Dolph L.; Gladyshev, Vadim N.

    2011-01-01

    Background Controlled generation and removal of hydrogen peroxide play important roles in cellular redox homeostasis and signaling. We used a hydrogen peroxide biosensor HyPer, targeted to different compartments, to examine these processes in mammalian cells. Principal Findings Reversible responses were observed to various redox perturbations and signaling events. HyPer expressed in HEK 293 cells was found to sense low micromolar levels of hydrogen peroxide. When targeted to various cellular compartments, HyPer occurred in the reduced state in the nucleus, cytosol, peroxisomes, mitochondrial intermembrane space and mitochondrial matrix, but low levels of the oxidized form of the biosensor were also observed in each of these compartments, consistent with a low peroxide tone in mammalian cells. In contrast, HyPer was mostly oxidized in the endoplasmic reticulum. Using this system, we characterized control of hydrogen peroxide in various cell systems, such as cells deficient in thioredoxin reductase, sulfhydryl oxidases or subjected to selenium deficiency. Generation of hydrogen peroxide could also be monitored in various compartments following signaling events. Conclusions We found that HyPer can be used as a valuable tool to monitor hydrogen peroxide generated in different cellular compartments. The data also show that hydrogen peroxide generated in one compartment could translocate to other compartments. Our data provide information on compartmentalization, dynamics and homeostatic control of hydrogen peroxide in mammalian cells. PMID:21283738

  4. Systems and methods for generation of hydrogen peroxide vapor

    DOEpatents

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

    2014-12-02

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

  5. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

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

  6. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2011-01-01

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

  7. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  8. High Temperature Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  9. 3-O-Benzyl-6-O-benzoyl-1,2-O-isopropil-idene-5-C-nitro-methyl-a-d-glucofuran-ose.

    PubMed

    Pampín, Begoña; Valencia, Laura; Estévez, Juan C; Estévez, Ramón J

    2009-01-17

    The title compound, C(24)H(27)NO(9), is one of the epimers of the Henry reaction of 3-O-benzyl-6-O-benzoyl-2-O-isopropyl-idene-a-d-glucofuran-5-one with nitro-methane. The conformation of the five membered rings is as expected from the precursor compound and the mol-ecule is folded with a dihedral angle of 51.4 (2)° between the aromatic rings. One O-H⋯O hydrogen bond and some intra-molecular and inter-molecular C-H⋯O inter-actions are observed in the structure.

  10. Fundamentals of ISCO Using Hydrogen Peroxide

    EPA Science Inventory

    Hydrogen peroxide is a common oxidant that has been applied extensively with in situ chemical oxidation (ISCO). Because of its widespread use in this and other fields, it has been extensively researched. This research has revealed that hydrogen peroxide has very complex chemistry...

  11. Hydrogen peroxide on the surface of Europa

    USGS Publications Warehouse

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

    1999-01-01

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

  12. Hydrogen peroxide on the surface of Europa.

    PubMed

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

    1999-03-26

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

  13. Orientation of N-benzoyl glycine on silver nanoparticles: SERS and DFT studies

    NASA Astrophysics Data System (ADS)

    Parameswari, A.; Asath, R. Mohamed; Premkumar, R.; Benial, A. Milton Franklin

    2017-05-01

    Surface enhanced Raman scattering (SERS) studies of N-benzoyl glycine (NBG) adsorbed on silver nanoparticles (AgNPs) was studied by experimental and density functional theory (DFT) approach. Single crystals of NBG were prepared using slow evaporation method. The AgNPs were prepared and characterized. The DFT/ B3PW91 method with LanL2DZ basis set was used to optimize the molecular structure of NBG and NBG adsorbed on silver cluster. The calculated and observed vibrational frequencies were assingned on the basis of potential energy distribution calculation. The reduced band gap value was obtained for NBG adsorbed on silver nanoparticles from the frontier molecular orbitals analysis. Natural bond orbital analysis was carried out to inspect the intra-molecular stabilization interactions, which are responsible for the bio activity and nonlinear optical property of the molecule. The spectral analysis was also evidenced that NBG would adsorb tilted orientation on the silver surface over the binding sites such as lone pair electron of N atom in amine group and through phenyl ring π system.

  14. K-ras mutations in benzotrichloride-induced lung tumors of A/J mice.

    PubMed

    You, M; Wang, Y; Nash, B; Stoner, G D

    1993-06-01

    Benzotrichloride (BTC) is used extensively as a chemical intermediate in the synthesis of benzoyl chloride and benzoyl peroxide. Epidemiological data suggest that BTC is a human lung carcinogen. BTC is also a carcinogen in the A/J mouse lung tumor bioassay. Activated K-ras protooncogenes were detected in BTC-induced lung tumors from A/J mice. The polymerase chain reaction was used to amplify specific DNA segments likely to contain activating mutations, and the amplified DNAs were sequenced to identify the mutation. The activating mutation present in the K-ras gene from all BTC-induced lung tumors (24/24) was a GC-->AT transition in codon 12. Thus, BTC may exert its carcinogenic action by activation of the K-ras protooncogene through a genotoxic mechanism.

  15. Hydrogen peroxide catalytic decomposition

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2010-01-01

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

  16. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 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 U.S...

  17. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 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 U.S...

  18. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 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 U.S...

  19. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    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 U.S...

  20. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 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 U.S...

  1. NASA Hydrogen Peroxide Propellant Hazards Technical Manual

    NASA Technical Reports Server (NTRS)

    Baker, David L.; Greene, Ben; Frazier, Wayne

    2005-01-01

    The Fire, Explosion, Compatibility and Safety Hazards of Hydrogen Peroxide NASA technical manual was developed at the NASA Johnson Space Center White Sands Test Facility. NASA Technical Memorandum TM-2004-213151 covers topics concerning high concentration hydrogen peroxide including fire and explosion hazards, material and fluid reactivity, materials selection information, personnel and environmental hazards, physical and chemical properties, analytical spectroscopy, specifications, analytical methods, and material compatibility data. A summary of hydrogen peroxide-related accidents, incidents, dose calls, mishaps and lessons learned is included. The manual draws from art extensive literature base and includes recent applicable regulatory compliance documentation. The manual may be obtained by United States government agencies from NASA Johnson Space Center and used as a reference source for hazards and safe handling of hydrogen peroxide.

  2. Oxidation of white phosphorus by peroxides in water

    NASA Astrophysics Data System (ADS)

    Abdreimova, R. R.; Akbaeva, D. N.; Polimbetova, G. S.

    2017-10-01

    A mixture of hypophosphorous, phosphorous, and phosphoric acids is formed during the anaerobic oxidation of white phosphorus by peroxides [ROOH; R = H, 3-ClC6H4CO, (CH3)3C] in water. The rate of reactions grows considerably upon adding nonpolar organic solvents. The activity series of peroxides and solvents are determined experimentally. NMR spectroscopy shows that the main product of the reaction is phosphorous acid, regardless of the nature of the peroxide and solvent. A radical mechanism of oxidation of white phosphorus by peroxides in water is proposed. It is initiated by the homolysis of peroxide with the formation of HO• radicals that are responsible for the homolytic opening of phosphoric tetrahedrons. Further oxidation and stages of the hydrolysis of intermediate phosphorus-containing compounds yield products of the reaction.

  3. PEROXIDE PROCESS FOR SEPARATION OF RADIOACTIVE MATERIALS

    DOEpatents

    Seaborg, G.T.; Perlman, I.

    1958-09-16

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

  4. Synthesis and X-ray structural investigation of (5R*,6S*)-1-benzoyl-5-methylthio-6-methoxy-1-azapenam

    NASA Astrophysics Data System (ADS)

    Krajewski, J. W.; Gluziński, P.; Grochowski, E.; Pupek, K.; Mishnyov, A.; Kemme, A.

    1992-08-01

    The compound (5R*,6S*)-1-benzoyl-5-methylthio-6-methoxy-1-azapenam ( 3) has been synthesized and its structure investigated by X-ray diffraction. The compound crystallizes in a monoclinic system, space group Cc, Z = 4, a = 12.01(1), b = 16.51(1), c = 8.048(6) Å, β = 115.87(6)°. The structure was solved by direct methods and refined by a full-matrix, least-squares procedure to give R = 0.070, Rw = 0.046, w = 1.34/(σ 2F). The expected cis configuration around the β-lactam ring was fully confirmed.

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

    PubMed

    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 (p<0.01). The GC group presented a significantly lower peroxide passage than did GD and GE (p<0.01). It can be concluded that the hydrogen peroxide placed into the pulp chamber passed through the

  6. EFFLUENT TREATMENT FACILITY PEROXIDE DESTRUCTION CATALYST TESTING

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 tomore » 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.« less

  7. Lipid peroxidation and neurodegenerative disease.

    PubMed

    Reed, Tanea T

    2011-10-01

    Lipid peroxidation is a complex process involving the interaction of oxygen-derived free radicals with polyunsaturated fatty acids, resulting in a variety of highly reactive electrophilic aldehydes. Since 1975, lipid peroxidation has been extensively studied in a variety of organisms. As neurodegenerative diseases became better understood, research establishing a link between this form of oxidative damage, neurodegeneration, and disease has provided a wealth of knowledge to the scientific community. With the advent of proteomics in 1995, the identification of biomarkers for neurodegenerative disorders became of paramount importance to better understand disease pathogenesis and develop potential therapeutic strategies. This review focuses on the relationship between lipid peroxidation and neurodegenerative diseases. It also demonstrates how findings in current research support the common themes of altered energy metabolism and mitochondrial dysfunction in neurodegenerative disorders. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Raman spectroscopy-based detection of chemical contaminants in food powders

    NASA Astrophysics Data System (ADS)

    Chao, Kuanglin; Dhakal, Sagar; Qin, Jianwei; Kim, Moon; Bae, Abigail

    2016-05-01

    Raman spectroscopy technique has proven to be a reliable method for qualitative detection of chemical contaminants in food ingredients and products. For quantitative imaging-based detection, each contaminant particle in a food sample must be detected and it is important to determine the necessary spatial resolution needed to effectively detect the contaminant particles. This study examined the effective spatial resolution required for detection of maleic acid in tapioca starch and benzoyl peroxide in wheat flour. Each chemical contaminant was mixed into its corresponding food powder at a concentration of 1% (w/w). Raman spectral images were collected for each sample, leveled across a 45 mm x 45 mm area, using different spatial resolutions. Based on analysis of these images, a spatial resolution of 0.5mm was selected as effective spatial resolution for detection of maleic acid in starch and benzoyl peroxide in flour. An experiment was then conducted using the 0.5mm spatial resolution to demonstrate Raman imaging-based quantitative detection of these contaminants for samples prepared at 0.1%, 0.3%, and 0.5% (w/w) concentrations. The results showed a linear correlation between the detected numbers of contaminant pixels and the actual concentrations of contaminant.

  9. [Azelaic acid 15% gel in the treatment of acne vulgaris. Combined results of two double-blind clinical comparative studies].

    PubMed

    Gollnick, Harald P M; Graupe, Klaus; Zaumseil, Rolf-Peter

    2004-10-01

    Topical measures are still the mainstay in the therapy of mild-to-moderate acne vulgaris. Azelaic acid 20% in a cream formulation has been established as an efficacious and safe topical drug for 15 years. A new non-alcoholic hydrogel formulation containing 15% azelaic acid was clinically tested against two standard drugs--5% benzoyl peroxide (BPO) and 1% clindamycin. In two independent, randomized, blinded comparative trials 15% azelaic acid gel was clinically tested against 5% benzoyl peroxide (BPO) gel in 351 patients and against 1% clindamycin gel in 229 patients. The drugs were applied b.i.d. for 4 months. Azelaic acid 15% gel proved to be as effective as BPO and clindamycin with median % reduction of the inflamed lesion (papules and pustules) of 70%, and 71% respectively. The azelaic acid gel was well-tolerated, the side effects (local burning and irritation) were distinctly less than with BPO but more pronounced than with clindamycin. Despite these side effects, the treatment was well-accepted by the majority of patients. Azelaic acid gel is an effective topical monotherapy for mild-to-moderate acne vulgaris; its new gel form is an enrichment of acne therapy.

  10. Stabilized aqueous hydrogen peroxide solution

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Malin, M.J.; Sciafani, L.D.

    1988-05-17

    This patent describes a stabilized aqueous hydrogen peroxide solution having a pH below 7 and an amount of Ferric ion up to about 2 ppm comprising hydrogen peroxide, acetanilide having a concentration which ranges between 0.74 M Mol/L and 2.22 mMol/L, and o-benzene disulfonic acid or salt thereof at a concentration between about 0.86 mMol/L to about 1.62 mMol/L.

  11. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in dough conditioning. (c) It is used or intended for...

  12. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in dough conditioning. (c) It is used or intended for...

  13. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in dough conditioning. (c) It is used or intended for...

  14. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in dough conditioning. (c) It is used or intended for...

  15. Hydrogen peroxide mechanosynthesis in siloxane-hydrogel contact lenses.

    PubMed

    Tavazzi, Silvia; Ferraro, Lorenzo; Cozza, Federica; Pastori, Valentina; Lecchi, Marzia; Farris, Stefano; Borghesi, Alessandro

    2014-11-26

    Drug-loaded contact lenses are emerging as the preferred treatment method for several ocular diseases, and efforts are being directed to promote extended and controlled delivery. One strategy is based on delivery induced by environmental triggers. One of these triggers can be hydrogen peroxide, since many platforms based on drug-loaded nanoparticles were demonstrated to be hydrogen-peroxide responsive. This is particularly interesting when hydrogen peroxide is the result of a specific pathophysiological condition. Otherwise, an alternative route to induce drug delivery is here proposed, namely the mechano-synthesis. The present work represents the proof-of-concept of the mechanosynthesis of hydrogen peroxide in siloxane-hydrogel contact lenses as a consequence of the cleavage of siloxane bonds at the interface between the polymer and water in aqueous phase. Their spongy morphology makes contact lenses promising systems for mechanical-to-chemical energy conversion, since the amount of hydrogen peroxide is expected to scale with the interfacial area between the polymer and water. The eyelid pressure during wear is sufficient to induce the hydrogen peroxide synthesis with concentrations which are biocompatible and suitable to trigger the drug release through hydrogen-peroxide-responsive platforms. For possible delivery on demand, the integration of piezoelectric polymers in the siloxane-hydrogel contact lenses could be designed, whose mechanical deformation could be induced by an applied wireless-controlled voltage.

  16. PROCESS OF ELIMINATING HYDROGEN PEROXIDE IN SOLUTIONS CONTAINING PLUTONIUM VALUES

    DOEpatents

    Barrick, J.G.; Fries, B.A.

    1960-09-27

    A procedure is given for peroxide precipitation processes for separating and recovering plutonium values contained in an aqueous solution. When plutonium peroxide is precipitated from an aqueous solution, the supernatant contains appreciable quantities of plutonium and peroxide. It is desirable to process this solution further to recover plutonium contained therein, but the presence of the peroxide introduces difficulties; residual hydrogen peroxide contained in the supernatant solution is eliminated by adding a nitrite or a sulfite to this solution.

  17. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... may be mixed with an edible carrier to give a concentration of: (1) 3 grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent per 100 grams of the additive, plus...

  18. Catalyst Development for Hydrogen Peroxide Rocket Engines

    NASA Technical Reports Server (NTRS)

    Morlan, P. W.; Wu, P.-K.; Ruttle, D. W.; Fuller, R. P.; Nejad, A. S.; Anderson, W. E.

    1999-01-01

    The development of various catalysts of hydrogen peroxide was conducted for the applications of liquid rocket engines. The catalyst development includes silver screen technology, solid catalyst technology, and homogeneous catalyst technology. The silver screen technology development was performed with 85% (by weight) hydrogen peroxide. The results of this investigation were used as the basis for the catalyst design of a pressure-fed liquid-fueled upper stage engine. Both silver-plated nickel 200 screens and pure silver screens were used as the active metal catalyst during the investigation, The data indicate that a high decomposition efficiency (greater than 90%) of 85% hydrogen peroxide can be achieved at a bed loading of 0.5 lbm/sq in/sec with both pure silver and silver plated screens. Samarium oxide coating, however, was found to retard the decomposition process and the catalyst bed was flooded at lower bed loading. A throughput of 200 lbm of hydrogen peroxide (1000 second run time) was tested to evaluate the catalyst aging issue and performance degradation was observed starting at approximately 400 seconds. Catalyst beds of 3.5 inch in diameter was fabricated using the same configuration for a 1,000-lbf rocket engine. High decomposition efficiency was obtained with a low pressure drop across the bed. Solid catalyst using precious metal was also developed for the decomposition of hydrogen peroxide from 85% to 98% by weight. Preliminary results show that the catalyst has a strong reactivity even after 15 minutes of peroxide decomposition. The development effort also includes the homogeneous catalyst technology. Various non-toxic catalysts were evaluated with 98% peroxide and hydrocarbon fuels. The results of open cup drop tests indicate an ignition delay around 11 ms.

  19. Protein oxidation and peroxidation

    PubMed Central

    Davies, Michael J.

    2016-01-01

    Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function. Unlike H2O2, which is rapidly removed by protective enzymes, protein peroxides are only slowly removed, and catabolism is a major fate. Although turnover of modified proteins by proteasomal and lysosomal enzymes, and other proteases (e.g. mitochondrial Lon), can be efficient, protein hydroperoxides inhibit these pathways and this may contribute to the accumulation of modified proteins in cells. Available evidence supports an association between protein oxidation and multiple human pathologies, but whether this link is causal remains to be established. PMID:27026395

  20. Acid- and base-catalysis in the mononuclear rearrangement of some (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole in toluene: effect of substituents on the course of reaction.

    PubMed

    D'Anna, Francesca; Frenna, Vincenzo; Ghelfi, Franco; Marullo, Salvatore; Spinelli, Domenico

    2011-04-15

    The reaction rates for the rearrangement of eleven (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole 3a-k into the relevant (2-aryl-5-phenyl-2H-1,2,3-triazol-4-yl)ureas 4a-k in the presence of trichloroacetic acid or of piperidine have been determined in toluene at 313.1 K. The results have been related to the effect of the aryl substituent by using Hammett and/or Ingold-Yukawa-Tsuno correlations and have been compared with those previously collected in a protic polar solvent (dioxane/water) as well as with those on the analogous rearrangement of the corresponding (Z)-arylhydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazole 1a-k in benzene. Some light can thus be shed on the general differences of chemical reactivity between protic polar (or dipolar aprotic) and apolar solvents.

  1. MEASUREMENT AND MODELING OF THE DRY DEPOSITION OF PEROXIDES

    EPA Science Inventory

    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...

  2. Sugar microanalysis by HPLC with benzoylation: improvement via introduction of a C-8 cartridge and a high efficiency ODS column.

    PubMed

    Miyagi, Michiko; Yokoyama, Hirokazu; Hibi, Toshifumi

    2007-07-01

    An HPLC protocol for sugar microanalysis based on the formation of ultraviolet-absorbing benzoyl chloride derivatives was improved. Here, samples were prepared with a C-8 cartridge and analyzed with a high efficiency ODS column, in which porous spherical silica particles 3 microm in diameter were packed. These devices allowed us to simultaneously quantify multiple sugars and sugar alcohols up to 10 ng/ml and to provide satisfactory separations of some sugars, such as fructose and myo-inositol and sorbitol and mannitol. This protocol, which does not require special apparatuses, should become a powerful tool in sugar research.

  3. Metal peroxide- polymer composites for dye degradation

    NASA Astrophysics Data System (ADS)

    Anshu, Ashwini; Vijayaraghavan, R.

    2017-11-01

    Semiconductor metal oxides/its composites with polymers have been explored for dye degradation through photocatalytic mechanism; these require UV or visible light for activation. Hence, there is need to develop (photo) catalyst that work in absence/presence of light. Towards this objective we are exploring metal peroxides and its composites for dye degradation. Here, we report our work on magnesium peroxide and its composites for dye degradation by photochemical pathways. The nanocomposites are synthesized from monomers and peroxides. The synthesized composites have been characterized by IR, DRS and powder XRD. The composites did not degrade dyes in dark.

  4. A Uranyl Peroxide Dimer in the Gas Phase

    DOE PAGES

    Dau, Phuong D.; Dau, Phuong V.; Rao, Linfeng; ...

    2017-03-14

    For this study, the gas-phase uranyl peroxide dimer, [(UO 2) 2(O2)(L) 2] 2+ where L = 2,2'-trifluoroethylazanediyl)bis(N,N'-dimethylacetamide), was synthesized by electrospray ionization of a solution of UO 2 2+ and L. Collision-induced dissociation of this dimer resulted in endothermic O atom elimination to give [(UO 2) 2(O)(L) 2] 2+, which was found to spontaneously react with water via exothermic hydrolytic chemisorption to yield [(UO 2) 2(OH) 2(L) 2] 2+. Density functional theory computations of the energies for the gas-phase reactions are in accord with observations. The structures of the observed uranyl dimer were computed, with that of the peroxide ofmore » particular interest, as a basis to evaluate the formation of condensed phase uranyl peroxides with bent structures. The computed dihedral angle in [(UO 2) 2(O 2)(L) 2] 2+ is 145°, indicating a substantial deviation from the planar structure with a dihedral angle of 180°. Energies needed to induce bending in the most elementary gas-phase uranyl peroxide complex, [(UO 2) 2(O 2)] 2+, were computed. It was found that bending from the lowest-energy planar structure to dihedral angles up to 140° required energies of <10 kJ/mol. The gas-phase results demonstrate the inherent stability of the uranyl peroxide moiety and support the notion that the uranyl-peroxide-uranyl structural unit is intrinsically planar, with only minor energy perturbations needed to form the bent structures found in studtite and uranyl peroxide nanostructures.« less

  5. Kinetics of lithium peroxide monohydrate thermal decomposition

    NASA Astrophysics Data System (ADS)

    Nefedov, Roman; Posternak, Nikolay; Ferapontov, Yuriy

    2017-11-01

    Topochemical dehydration of lithium peroxide was studied to determine kinetic parameters at the range of temperatures from 90°C to 147°C in non-isothermal conditions by derivatographic method. The study was conducted to select optimal conditions of lithium peroxide synthesis in dehydration reaction of triple LiOH-H2O2-H2O system in ultra-high frequency radiation field. Conditions of dehydration reaction were caused by the thermal conductivity of LiOH -H2O2-H2O system. It is determined that dehydration process runs close to the first order reaction (n=0.85±0.03). The activation energy and pre-exponential factor values were found as Eak = 86.0 ± 0.8 kJ/mol, k0 = (2.19 ± 0.16) .1011 min-1, correspondingly. It is supposed that there is a similarity between the dehydration mechanism of lithium peroxide monohydrate and peroxide hydrates of alkaline-earth metals (calcium, barium and strontium).

  6. Progress toward hydrogen peroxide micropulsion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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.

  7. Synthesis and thermal properties of strontium and calcium peroxides

    NASA Technical Reports Server (NTRS)

    Philipp, Warren H.; Kraft, Patricia A.

    1989-01-01

    A practical synthesis and a discussion of some chemical properties of pure strontium peroxide and calcium peroxide are presented. The general synthesis of these peroxides involves precipitation of their octahydrates by addition of H2O2 to aqueous ammoniacal Sr(NO3)2 or CaCl2. The octahydrates are converted to the anhydrous peroxides by various dehydration techniques. A new x-ray diffraction powder pattern for CaO2 x 8H2O is given from which lattice parameters a=6.212830 and c=11.0090 were calculated on the basis of the tetragonal crystal system.

  8. Glycerophosphate-dependent peroxide production by brown fat mitochondria from newborn rats.

    PubMed

    Drahota, Z; Rauchova, H; Jesina, P; Vojtísková, A; Houstek, J

    2003-03-01

    Glycerophosphate (GP)-dependent, ferricyanide-induced hydrogen peroxide production was studied in brown adipose tissue mitochondria from newborn rats. Relations between the rate of hydrogen peroxide production and total amount of hydrogen peroxide produced at different GP and ferricyanide concentrations were determined. It was found that the rate of hydrogen peroxide production increases with increasing GP concentration and decreases with increasing ferricyanide concentration. Total amount of hydrogen peroxide produced increases with increasing ferricyanide concentration, however, not proportionally, and the efficiency of this process (oxygen/ferricyanide ratio) strongly declines. Data presented provide further information on the character and kinetics of hydrogen peroxide production by mammalian mitochondrial glycerophosphate dehydrogenase.

  9. Molecular Association and Structure of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Giguere, Paul A.

    1983-01-01

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

  10. Selective detection of vapor phase hydrogen peroxide with phthalocyanine chemiresistors.

    PubMed

    Bohrer, Forest I; Colesniuc, Corneliu N; Park, Jeongwon; Schuller, Ivan K; Kummel, Andrew C; Trogler, William C

    2008-03-26

    The use of hydrogen peroxide as a precursor to improvised explosives has made its detection a topic of critical importance. Chemiresistor arrays comprised of 50 nm thick films of metallophthalocyanines (MPcs) are redox selective vapor sensors of hydrogen peroxide. Hydrogen peroxide is shown to decrease currents in cobalt phthalocyanine sensors while it increases currents in nickel, copper, and metal-free phthalocyanine sensors; oxidation and reduction of hydrogen peroxide via catalysis at the phthalocyanine surface are consistent with the pattern of sensor responses. This represents the first example of MPc vapor sensors being oxidized and reduced by the same analyte by varying the metal center. Consequently, differential analysis by redox contrast with catalytic amplification using a small array of sensors may be used to uniquely identify peroxide vapors. Metallophthalocyanine chemiresistors represent an improvement over existing peroxide vapor detection technologies in durability and selectivity in a greatly decreased package size.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 samemore » 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.« less

  12. Alkaline peroxide treatment of ECF bleached softwood kraft pulps. Part 1. characterizing the effect of alkaline peroxide treatment on carboxyl groups of fibers

    Treesearch

    Zheng Dang; Thomas Elder; Arthur J. Ragauskas

    2007-01-01

    The influence of alkaline peroxide treatment has been characterized on elementally chlorine-free (ECF) bleached softwood (SW) kraft pulp. The results indicate that fiber charge increased with an increase in peroxide charge: a maximum fiber charge increment of 16.6% was obtained with 8.0% more peroxide charge on oven-dried (0.d.) pulp at 60.0°C. Two primary bleaching...

  13. On the cleavage of the peroxide O---O bond in methyl hydroperoxide and dimethyl peroxide upon protonation

    NASA Astrophysics Data System (ADS)

    Schalley, Christoph A.; Dieterle, Martin; Schröder, Detlef; Schwarz, Helmut; Uggerud, Einar

    1997-04-01

    The unimolecular decays of protonated methyl hydroperoxide and dimethyl peroxide have been studied by tandem mass spectrometric techniques in combination with isotopic labeling as well as computational methods. The potential-energy surfaces calculated at the BECKE3LYP/6-311++G** level of theory are in good agreement with the experimental findings. The decomposition of the protonated peroxides can be described by a general mechanistic scheme which involves rearrangement to proton-bridged complexes, i.e. [CH2O-H-OH2]+ and [CH2O-H-O(H)CH3]+, respectively. When formed unimolecularly via rearrangement of the protonated peroxides, these complexes are rovibrationally highly excited; consequently, their fragmentations are affected remarkably as compared to proton-bound complexes of lower internal energy which are independently generated from the corresponding alcohol and carbonyl compounds in a chemical ionization plasma. For methyl hydroperoxide, both oxygen atoms can be protonated, giving rise to two isomeric cations with rather similar heats of formation but entirely different fragmentation behaviors. Cleavage of the O---O bond in dimethyl peroxide upon protonation results in proton- as well as methyl-cation-bridged intermediates, e.g. [CH2O-H-O(H)CH3]+ and [CH2O-CH3-OH2]+.

  14. Carcinogenicity of benzyl chloride, benzal chloride, benzotrichloride and benzoyl chloride in mice by skin application.

    PubMed

    Fukuda, K; Matsushita, H; Sakabe, H; Takemoto, K

    1981-10-01

    The carcinogenicity of benzyl chloride (BYC), benzal chloride (BAC), benzotrichloride (BTC) and benzoyl chloride (BOC), which were suspected as causative agents of lung cancer and maxillary malignant lymphoma of workers employed in factories producing BOC, was examined by skin applications in female ICR mice. After rather high dose exposure, BTC exhibited leukemogenic and pulmonary tumorigenic activities as well as potent dermal carcinogenic activity. After administration of the chemicals at the dose of 2.3 microliter/animal, twice a week for 50 weeks, BTC induced 68% incidence of skin cancers and 58% incidence of pulmonary tumors (including 10% of lung carcinomas) within 399 days. Incidence of skin cancers was 58% for BAC, 15% for BYC and 10% for BOC within 560 days. Considering the extent of possible exposure of the workers to these chemicals in the working environment and the carcinogenic potency of the chemicals tested, it can be concluded that BTC was very probably responsible for causing the cancers seen int he workers employed in manufacturing BOC.

  15. Hazard Assessment of Personal Protective Clothing for Hydrogen Peroxide Service

    NASA Technical Reports Server (NTRS)

    Greene, Ben; McClure, Mark B.; Johnson, Harry T.

    2004-01-01

    Selection of personal protective equipment (PPE) for hydrogen peroxide service is an important part of the hazard assessment process. But because drip testing of chemical protective clothing for hydrogen peroxide service has not been reported for about 40 years, it is of great interest to test new protective clothing materials with new, high-concentration hydrogen peroxide following similar procedures. The suitability of PPE for hydrogen peroxide service is in part determined by observations made when hydrogen peroxide is dripped onto swatches of protective clothing material. Protective clothing material was tested as received, in soiled condition, and in grossly soiled condition. Materials were soiled by pretreating the material with potassium permanganate (KMnO4) solution then drying to promote a reaction. Materials were grossly soiled with solid KMnO4 to greatly promote reaction. Observations of results including visual changes to the hydrogen peroxide and materials, times to ignition, and self-extinguishing characteristics of the materials are reported.

  16. Polymer concrete composites for the production of high strength pipe and linings in high temperature corrosive environments

    DOEpatents

    Zeldin, A.; Carciello, N.; Fontana, J.; Kukacka, L.

    High temperature corrosive resistant, non-aqueous polymer concrete composites are described. They comprise about 12 to 20% by weight of a water-insoluble polymer binder polymerized in situ from a liquid monomer mixture consisting essentially of about 40 to 70% by weight of styrene, about 25 to 45% by weight acrylonitrile and about 2.5 to 7.5% by weight acrylamide or methacrylamide and about 1 to 10% by weight of a crosslinking agent. This agent is selected from the group consisting of trimethylolpropane trimethacrylate and divinyl benzene; and about 80 to 88% by weight of an inert inorganic filler system containing silica sand and portland cement, and optionally Fe/sub 2/O/sub 3/ or carbon black or mica. A free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other organic peroxides and combinations thereof to initiate crosspolymerization of the monomer mixture in the presence of said inorganic filler.

  17. Design, synthesis, and anti-melanogenic effects of (E)-2-benzoyl-3-(substituted phenyl)acrylonitriles

    PubMed Central

    Yun, Hwi Young; Kim, Do Hyun; Son, Sujin; Ullah, Sultan; Kim, Seong Jin; Kim, Yeon-Jeong; Yoo, Jin-Wook; Jung, Yunjin; Chun, Pusoon; Moon, Hyung Ryong

    2015-01-01

    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 phenyl)acrylonitriles (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. PMID:26347064

  18. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Silver nitrate and hydrogen peroxide solution. 172... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution containing a mixture of silver nitrate and hydrogen peroxide may be safely used...

  19. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Silver nitrate and hydrogen peroxide solution. 172... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution containing a mixture of silver nitrate and hydrogen peroxide may be safely used...

  20. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Silver nitrate and hydrogen peroxide solution. 172... Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution containing a mixture of silver nitrate and hydrogen peroxide may be safely used in accordance with the following...

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Silver nitrate and hydrogen peroxide solution. 172... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution containing a mixture of silver nitrate and hydrogen peroxide may be safely used...

  2. Electron transfer catalysis with monolayer protected Au25 clusters

    NASA Astrophysics Data System (ADS)

    Antonello, Sabrina; Hesari, Mahdi; Polo, Federico; Maran, Flavio

    2012-08-01

    Au25L18 (L = S(CH2)2Ph) clusters were prepared and characterized. The resulting monodisperse clusters were reacted with bis(pentafluorobenzoyl) peroxide in dichloromethane to form Au25L18+ quantitatively. The kinetics and thermodynamics of the corresponding electron transfer (ET) reactions were characterized via electrochemistry and thermochemical calculations. Au25L18+ was used in homogeneous redox catalysis experiments with a series of sym-substituted benzoyl peroxides, including the above peroxide, bis(para-cyanobenzoyl) peroxide, dibenzoyl peroxide, and bis(para-methoxybenzoyl) peroxide. Peroxide dissociative ET was catalyzed using both the Au25L18/Au25L18- and the Au25L18+/Au25L18 redox couples as redox mediators. Simulation of the CV curves led to determination of the ET rate constant (kET) values for concerted dissociative ET to the peroxides. The ET free energy ΔG° could be estimated for all donor-acceptor combinations, leading to observation of a nice activation-driving force (log kETvs. ΔG°) relationship. Comparison with the kET obtained using a ferrocene-type donor with a formal potential similar to that of Au25L18/Au25L18- showed that the presence of the capping monolayer affects the ET rate rather significantly, which is attributed to the intrinsic nonadiabaticity of peroxide acceptors.Au25L18 (L = S(CH2)2Ph) clusters were prepared and characterized. The resulting monodisperse clusters were reacted with bis(pentafluorobenzoyl) peroxide in dichloromethane to form Au25L18+ quantitatively. The kinetics and thermodynamics of the corresponding electron transfer (ET) reactions were characterized via electrochemistry and thermochemical calculations. Au25L18+ was used in homogeneous redox catalysis experiments with a series of sym-substituted benzoyl peroxides, including the above peroxide, bis(para-cyanobenzoyl) peroxide, dibenzoyl peroxide, and bis(para-methoxybenzoyl) peroxide. Peroxide dissociative ET was catalyzed using both the Au25L18/Au25L18- and

  3. Uranyl peroxide enhanced nuclear fuel corrosion in seawater.

    PubMed

    Armstrong, Christopher R; Nyman, May; Shvareva, Tatiana; Sigmon, Ginger E; Burns, Peter C; Navrotsky, Alexandra

    2012-02-07

    The Fukushima-Daiichi nuclear accident brought together compromised irradiated fuel and large amounts of seawater in a high radiation field. Based on newly acquired thermochemical data for a series of uranyl peroxide compounds containing charge-balancing alkali cations, here we show that nanoscale cage clusters containing as many as 60 uranyl ions, bonded through peroxide and hydroxide bridges, are likely to form in solution or as precipitates under such conditions. These species will enhance the corrosion of the damaged fuel and, being thermodynamically stable and kinetically persistent in the absence of peroxide, they can potentially transport uranium over long distances.

  4. Uranyl peroxide enhanced nuclear fuel corrosion in seawater

    PubMed Central

    Armstrong, Christopher R.; Nyman, May; Shvareva, Tatiana; Sigmon, Ginger E.; Burns, Peter C.; Navrotsky, Alexandra

    2012-01-01

    The Fukushima-Daiichi nuclear accident brought together compromised irradiated fuel and large amounts of seawater in a high radiation field. Based on newly acquired thermochemical data for a series of uranyl peroxide compounds containing charge-balancing alkali cations, here we show that nanoscale cage clusters containing as many as 60 uranyl ions, bonded through peroxide and hydroxide bridges, are likely to form in solution or as precipitates under such conditions. These species will enhance the corrosion of the damaged fuel and, being thermodynamically stable and kinetically persistent in the absence of peroxide, they can potentially transport uranium over long distances. PMID:22308442

  5. Peroxiredoxin 2 and peroxide metabolism in the erythrocyte.

    PubMed

    Low, Felicia M; Hampton, Mark B; Winterbourn, Christine C

    2008-09-01

    Peroxiredoxin 2 (Prx2) is an antioxidant enzyme that uses cysteine residues to decompose peroxides. Prx2 is the third most abundant protein in erythrocytes, and competes effectively with catalase and glutathione peroxidase to scavenge low levels of hydrogen peroxide, including that derived from hemoglobin autoxidation. Low thioredoxin reductase activity in the erythrocyte is able to keep up with this basal oxidation and maintain the Prx2 in its reduced form, but exposure to exogenous hydrogen peroxide causes accumulation of the disulfide-linked dimer. The high cellular concentration means that although turnover is slow, erythrocyte Prx2 can act as a noncatalytic scavenger of hydrogen peroxide and a sink for hydrogen peroxide before turnover becomes limiting. The consequences of Prx2 oxidation for the erythrocyte are not well characterized, but mice deficient in this protein develop severe hemolytic anemia associated with Heinz body formation. Prx2, also known as calpromotin, regulates ion transport by associating with the membrane and activating the Gárdos channel. How Prx2 redox transformations are linked to membrane association and channel activation is yet to be established. In this review, we discuss the functional properties of Prx2 and its role as a major component of the erythrocyte antioxidant system.

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

    PubMed Central

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

    2014-01-01

    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. PMID:23791092

  7. Supra-molecular architecture in a co-crystal of the N(7)-H tautomeric form of N (6)-benzoyl-adenine with adipic acid (1/0.5).

    PubMed

    Swinton Darious, Robert; Thomas Muthiah, Packianathan; Perdih, Franc

    2016-06-01

    The asymmetric unit of the title co-crystal, C12H9N5O·0.5C6H10O4, consists of one mol-ecule of N (6)-benzoyl-adenine (BA) and one half-mol-ecule of adipic acid (AA), the other half being generated by inversion symmetry. The dihedral angle between the adenine and phenyl ring planes is 26.71 (7)°. The N (6)-benzoyl-adenine mol-ecule crystallizes in the N(7)-H tautomeric form with three non-protonated N atoms. This tautomeric form is stabilized by intra-molecular N-H⋯O hydrogen bonding between the carbonyl (C=O) group and the N(7)-H hydrogen atom on the Hoogsteen face of the purine ring, forming an S(7) ring motif. The two carboxyl groups of adipic acid inter-act with the Watson-Crick face of the BA mol-ecules through O-H⋯N and N-H⋯O hydrogen bonds, generating an R 2 (2)(8) ring motif. The latter units are linked by N-H⋯N hydrogen bonds, forming layers parallel to (10-5). A weak C-H⋯O hydrogen bond is also present, linking adipic acid mol-ecules in neighbouring layers, enclosing R (2) 2(10) ring motifs and forming a three-dimensional structure. C=O⋯π and C-H⋯π inter-actions are also present in the structure.

  8. 3-O-Benzyl-6-O-benzoyl-1,2-O-isopropil­idene-5-C-nitro­methyl-a-d-glucofuran­ose

    PubMed Central

    Pampín, Begoña; Valencia, Laura; Estévez, Juan C.; Estévez, Ramón J.

    2009-01-01

    The title compound, C24H27NO9, is one of the epimers of the Henry reaction of 3-O-benzyl-6-O-benzoyl-2-O-isopropyl­idene-a-d-glucofuran-5-one with nitro­methane. The conformation of the five membered rings is as expected from the precursor compound and the mol­ecule is folded with a dihedral angle of 51.4 (2)° between the aromatic rings. One O—H⋯O hydrogen bond and some intra­molecular and inter­molecular C—H⋯O inter­actions are observed in the structure. PMID:21581936

  9. METHOD AND MEANS FOR RADIATION DOSIMETRY

    DOEpatents

    Shulte, J.W.; Suttle, J.F.

    1958-02-18

    This patent relates to a method and device for determining quantities of gamma radiation and x radiation by exposing to such radiation a mature of a purified halogenated hydrocarbon chosen from the class consisting of chloroform, bromoform, tetrachloroethane and 1,1,2trichloroethane, and a minor quantity of a sensitizer chosen from the class consisting of oxygen, benzoyl peroxide, sodium peroxide, and nitrobenzene, the proportion of the sensitizer being at least about 10/sup -5/ moles per cubic centimeter of halogenated hydrocarbon, the total amount of sensitizer depending upon the range of radiation to be measured, and chemically measuring the amount of decomposition generated by the irradiation of the sensitized halogenated hydrocarbon.

  10. Unsolved mysteries: How does lipid peroxidation cause ferroptosis?

    PubMed Central

    Feng, Huizhong

    2018-01-01

    Ferroptosis is a cell death process driven by damage to cell membranes and linked to numerous human diseases. Ferroptosis is caused by loss of activity of the key enzyme that is tasked with repairing oxidative damage to cell membranes—glutathione peroxidase 4 (GPX4). GPX4 normally removes the dangerous products of iron-dependent lipid peroxidation, protecting cell membranes from this type of damage; when GPX4 fails, ferroptosis ensues. Ferroptosis is distinct from apoptosis, necroptosis, necrosis, and other modes of cell death. Several key mysteries regarding how cells die during ferroptosis remain unsolved. First, the drivers of lipid peroxidation are not yet clear. Second, the subcellular location of lethal lipid peroxides remains an outstanding question. Finally, how exactly lipid peroxidation leads to cell death is an unsolved mystery. Answers to these questions will provide insights into the mechanisms of ferroptotic cell death and associated human diseases, as well as new therapeutic strategies for such diseases. PMID:29795546

  11. A survey of chemicals inducing lipid peroxidation in biological systems.

    PubMed

    Kappus, H

    1987-01-01

    A great number of drugs and chemicals are reviewed which have been shown to stimulate lipid peroxidation in any biological system. The underlying mechanisms, as far as known, are also dealt with. Lipid peroxidation induced by iron ions, organic hydroperoxides, halogenated hydrocarbons, redox cycling drugs, glutathione depleting chemicals, ethanol, heavy metals, ozone, nitrogen dioxide and a number of miscellaneous compounds, e.g. hydrazines, pesticides, antibiotics, are mentioned. It is shown that lipid peroxidation is stimulated by many of these compounds. However, quantitative estimates cannot be given yet and it is still impossible to judge the biological relevance of chemical-induced lipid peroxidation.

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

    NASA Technical Reports Server (NTRS)

    Barta, Daniel J.; Henderson, Keith

    2000-01-01

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

  13. Hydrogen Peroxide - Material Compatibility Studied by Microcalorimetry

    NASA Technical Reports Server (NTRS)

    Homung, Steven D.; Davis, Dennis D.; Baker, David; Popp, Christopher G.

    2003-01-01

    Environmental and toxicity concerns with current hypergolic propellants have led to a renewed interest in propellant grade hydrogen peroxide (HP) for propellant applications. Storability and stability has always been an issue with HP. Contamination or contact of HP with metallic surfaces may cause decomposition, which can result in the evolution of heat and gas leading to increased pressure or thermal hazards. The NASA Johnson Space Center White Sands Test Facility has developed a technique to monitor the decompositions of hydrogen peroxide at temperatures ranging from 25 to 60 C. Using isothermal microcalorimetry we have measured decomposition rates at the picomole/s/g level showing the catalytic effects of materials of construction. In this paper we will present the results of testing with Class 1 and 2 materials in 90 percent hydrogen peroxide.

  14. Evaluating different concentrations of hydrogen peroxide in an automated room disinfection system.

    PubMed

    Murdoch, L E; Bailey, L; Banham, E; Watson, F; Adams, N M T; Chewins, J

    2016-09-01

    A comparative study was made on the efficacy of 5, 10 and 35% weight by weight (w/w) hydrogen peroxide solutions when applied using an automated room disinfection system. Six-log biological indicators of methicillin-resistant Staphylococcus aureus (MRSA) and Geobacillus stearothermophilus were produced on stainless steel coupons and placed within a large, sealed, environmentally controlled enclosure. Five percent hydrogen peroxide was distributed throughout the enclosure using a Bioquell hydrogen peroxide vapour generator (BQ-50) for 40 min and left to reside for a further 200 min. Biological indicators were removed at 10-min intervals throughout the first 120 min of the process. The experiment was repeated for 10 and 35% hydrogen peroxide solutions. Five percent and 10% hydrogen peroxide solutions failed to achieve any reduction of MRSA, but achieved full kill of G. stearothermophilus spores at 70 and 40 min respectively. Thirty-five percent hydrogen peroxide achieved a 6-log reduction of MRSA after 30 min and full kill of G. stearothermophilus at 20 min. The concentration of 5% hydrogen peroxide within the enclosure after the 200-min dwell was measured at 9·0 ppm. This level exceeds the 15-min Short Term Exposure Limit (STEL) for hydrogen peroxide of 2·0 ppm. Users of automated hydrogen peroxide disinfection systems should review system efficacy and room re-entry protocols in light of these results. This research allows hospital infection control teams to consider the impact and risks of using low concentrations of hydrogen peroxide for disinfection within their facilities, and to question automated room disinfection system providers on the efficacy claims they make. The evidence that low concentration hydrogen peroxide solutions do not rapidly, autonomously break down, is in contradiction to the claims made by some hydrogen peroxide equipment providers and raises serious health and safety concerns. Facilities using hydrogen peroxide systems that

  15. The mechanism of Fe(2+)-initiated lipid peroxidation in liposomes: the dual function of ferrous ions, the roles of the pre-existing lipid peroxides and the lipid peroxyl radical.

    PubMed Central

    Tang, L; Zhang, Y; Qian, Z; Shen, X

    2000-01-01

    The mechanism of Fe(2+)-initiated lipid peroxidation in a liposomal system was studied. It was found that a second addition of ferrous ions within the latent period lengthened the time lag before lipid peroxidation started. The apparent time lag depended on the total dose of Fe(2+) whenever the second dose of Fe(2+) was added, which indicates that Fe(2+) has a dual function: to initiate lipid peroxidation on one hand and suppress the species responsible for the initiation of the peroxidation on the other. When the pre-existing lipid peroxides (LOOH) were removed by incorporating triphenylphosphine into liposomes, Fe(2+) could no longer initiate lipid peroxidation and the acceleration of Fe(2+) oxidation by the liposomes disappeared. However, when extra LOOH were introduced into liposomes, both enhancement of the lipid peroxidation and shortening of the latent period were observed. When the scavenger of lipid peroxyl radicals (LOO(.)), N,N'-diphenyl-p-phenylene-diamine, was incorporated into liposomes, neither initiation of the lipid peroxidation nor acceleration of the Fe(2+) oxidation could be detected. The results may suggest that both the pre-existing LOOH and LOO(.) are necessary for the initiation of lipid peroxidation. The latter comes initially from the decomposition of the pre-existing LOOH by Fe(2+) and can be scavenged by its reaction with Fe(2+). Only when Fe(2+) is oxidized to such a degree that LOO(.) is no longer effectively suppressed does lipid peroxidation start. It seems that by taking the reactions of Fe(2+) with LOOH and LOO(.) into account, the basic chemistry in lipid peroxidation can explain fairly well the controversial phenomena observed in Fe(2+)-initiated lipid peroxidation, such as the existence of a latent period, the critical ratio of Fe(2+) to lipid and the required oxidation of Fe(2+). PMID:11062055

  16. Demonstration of the Catalytic Decomposition of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    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)

  17. Improved Electrolytic Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    James, Patrick I.

    2005-01-01

    An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2.

  18. Oxygen Mass Flow Rate Generated for Monitoring Hydrogen Peroxide Stability

    NASA Technical Reports Server (NTRS)

    Ross, H. Richard

    2002-01-01

    Recent interest in propellants with non-toxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because peroxide is sensitive to contaminants, material interactions, stability and storage issues, monitoring decomposition rates is important. Stennis Space Center (SSC) uses thermocouples to monitor bulk fluid temperature (heat evolution) to determine reaction rates. Unfortunately, large temperature rises are required to offset the heat lost into the surrounding fluid. Also, tank penetration to accomodate a thermocouple can entail modification of a tank or line and act as a source of contamination. The paper evaluates a method for monitoring oxygen evolution as a means to determine peroxide stability. Oxygen generation is not only directly related to peroxide decomposition, but occurs immediately. Measuring peroxide temperature to monitor peroxide stability has significant limitations. The bulk decomposition of 1% / week in a large volume tank can produce in excess of 30 cc / min. This oxygen flow rate corresponds to an equivalent temperature rise of approximately 14 millidegrees C, which is difficult to measure reliably. Thus, if heat transfer were included, there would be no temperature rise. Temperature changes from the surrounding environment and heat lost to the peroxide will also mask potential problems. The use of oxygen flow measurements provides an ultra sensitive technique for monitoring reaction events and will provide an earlier indication of an abnormal decomposition when compared to measuring temperature rise.

  19. THE PRODUCTION OF HYDROGEN PEROXIDE BY HIGH OXYGEN PRESSURES

    PubMed Central

    Gilbert, Daniel L.; Gerschman, Rebeca; Ruhm, K. Barclay; Price, William E.

    1958-01-01

    Hydrogen peroxide is formed in solutions of glutathione exposed to oxygen. This hydrogen peroxide or its precursors will decrease the viscosity of polymers like desoxyribonucleic acid and sodium alginate. Further knowledge of the mechanism of these chemical effects of oxygen might further the understanding of the biological effects of oxygen. This study deals with the rate of solution of oxygen and with the decomposition of hydrogen peroxide in chemical systems exposed to high oxygen pressures. At 6 atmospheres, the absorption coefficient for oxygen into water was about 1 cm./hour and at 143 atmospheres, it was about 2 cm./hour; the difference probably being due to the modus operandi. The addition of cobalt (II), manganese (II), nickel (II), or zinc ions in glutathione (GSH) solutions exposed to high oxygen pressure decreased the net formation of hydrogen peroxide and also the reduced glutathione remaining in the solution. Studies on hydrogen peroxide decomposition indicated that these ions act probably by accelerating the hydrogen perioxide oxidation of glutathione. The chelating agent, ethylenediaminetetraacetic acid disodium salt, inhibited the oxidation of GSH exposed to high oxygen pressure for 14 hours. However, indication that oxidation still occurred, though at a much slower rate, was found in experiments lasting 10 weeks. Thiourea decomposed hydrogen peroxide very rapidly. When GSH solutions were exposed to high oxygen pressure, there was oxidation of the GSH, which became relatively smaller with increasing concentrations of GSH. PMID:13525677

  20. Quantifying intracellular hydrogen peroxide perturbations in terms of concentration

    PubMed Central

    Huang, Beijing K.; Sikes, Hadley D.

    2014-01-01

    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. PMID:25460730

  1. A Modified Demonstration of the Catalytic Decomposition of Hydrogen Peroxide

    NASA Astrophysics Data System (ADS)

    Trujillo, Carlos Alexander

    2005-06-01

    A safer and cheaper version of the popular catalyzed decomposition of hydrogen peroxide demonstration commonly called the “Elephants’ Toothpaste” is presented. Hydrogen peroxide is decomposed in the presence of a surfactant by the enzyme catalase producing foam. Catalase has a higher activity compared with the traditional iodide and permits the use of diluted hydrogen peroxide solutions. The demonstration can be made with household products with similar amazing effects.

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

    PubMed

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

    2015-12-01

    Dysentery is an inflammation of the intestine caused by the protozoan parasite Entamoeba histolytica and is a recurrent health problem affecting millions of people worldwide. Because of the magnitude of this disease, finding novel strategies for treatment that does not affect human cells is necessary. Ergosterol peroxide is a sterol particularly known as a major cytotoxic agent with a wide spectrum of biological activities produced by edible and medicinal mushrooms. The aim of this report is to evaluate the amoebicidal activity of ergosterol peroxide (5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol isolated from 5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol) (Jacq.) P. Kumm. f. sp. Florida. Our results show that ergosterol peroxide produced a strong cytotoxic effect against amoebic growth. The inhibitory concentration IC50 of ergosterol peroxide was evaluated. The interaction between E. histolytica and ergosterol peroxide in vitro resulted in strong amoebicidal activity (IC50  = 4.23 nM) that may be due to the oxidatory effect on the parasitic membrane. We also tested selective toxicity of ergosterol peroxide using a cell line CCL-241, a human epithelial cell line isolated from normal human fetal intestinal tissue. To the best of our knowledge, this is the first report on the cytotoxicity of ergosterol peroxide against E. histolytica, which uncovers a new biological property of the lipidic compound isolated from Pleurotus ostreatus (Jacq.) P. Kumm. f. sp. Florida. Copyright © 2015 John Wiley & Sons, Ltd.

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

    PubMed

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

    2015-10-01

    The applicability of acid degradation of organic peroxides into hydrogen peroxide in a pneumatically driven flow injection system with chemiluminescence reaction with luminol and Cu(2+) as a catalyst (FIA-CL) was investigated for the fast and sensitive detection of organic peroxide explosives (OPEs). The target OPEs included hexamethylene triperoxide diamine (HMTD), triacetone triperoxide (TATP) and methylethyl ketone peroxide (MEKP). Under optimised conditions maximum degradations of 70% and 54% for TATP and HMTD, respectively were achieved at 162 µL min(-1), and 9% degradation for MEKP at 180 µL min(-1). Flow rates were precisely controlled in this single source pneumatic pressure driven multi-channel FIA system by model experiments on mixing of easily detectable component solutions. The linear range for detection of TATP, HMTD and H2O2 was 1-200 µM (r(2)=0.98-0.99) at both flow rates, while that for MEKP was 20-200 µM (r(2)=0.97) at 180 µL min(-1). The detection limits (LODs) obtained were 0.5 µM for TATP, HMTD and H2O2 and 10 µM for MEKP. The detection times varied from 1.5 to 3 min in this FIA-CL system. Whilst the LOD for H2O2 was comparable with those reported by other investigators, the LODs and analysis times for TATP and HMTD were superior, and significantly, this is the first time the detection of MEKP has been reported by FIA-CL. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Lipid peroxidation in sarcoplasmic reticulum membranes: effect on functional and biophysical properties.

    PubMed

    Dinis, T C; Almeida, L M; Madeira, V M

    1993-03-01

    The fluorescent polyunsaturated parinaric acid (PnA) incorporated in sarcoplasmic reticulum membranes (SR) was used to probe the initial stages of membrane lipid peroxidation. The experimental set up of the PnA assay was investigated by means of several peroxidation initiators to ascertain peroxidation conditions. This assay in SR is particularly useful to evaluate the membrane susceptibility to peroxidation and to ascertain suitable conditions (concentration of initiators and cofactors) to challenge peroxidation in each preparation under study. On the basis of the PnA assay, Fe2+/ascorbate was selected among the different initiator systems to assess the effect of lipid peroxidation upon biochemical and biophysical parameters of SR membranes. Under mildly controlled conditions at 25 degrees C, the lipid degradative process, as detected by fatty acid analysis, decreases the Ca2+ uptake (up to about 50% of control) and reduces the Ca2+ pump efficiency (Ca2+/ATP ratio) up to about 58% of control, without inactivation the ATPase enzyme turnover. The effect of lipid peroxidation on the SR bilayer organization is dependent either on the extent of lipid peroxidation or on the depth of the bilayer as probed by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene and by intramolecular excimerization of 1,3-di(1-pyrenyl)propane. It is concluded that the effect of mild lipid peroxidation on Ca2+ pump activity is partially exerted through the alteration of physical properties in the lipid phase or lipid-protein interfaces.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  8. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  9. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  10. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  11. ELECTRON SPIN RESONANCE STUDIES ON PEROXIDE RADICALS IN IRRADIATED POLYPROPYLENE (in German)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fischer, H.; Hellwege, K.-H.; Neudoerfl, P.

    1963-06-01

    Peroxide radicals are formed by oxidation of carbon radicals in irradiated isotactic polypropylene. An interpretation of their ESR spectra is given. The recombination of the peroxide radicals follows a chain reaction mechanism, which is derived from the reversibility of formation of peroxide radicals, the time dependence of their concentration, and from the oxygen consumption of samples containing peroxide radicals. The reactions are discussed in view of the radiation induced oxidative degradation of polypropylene. (auth)

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

    NASA Astrophysics Data System (ADS)

    Shengchu, Qi; Jilan, Wu; Yan, Zhu

    1993-07-01

    In order to determine the level of organic peroxides induced by autooxidation, random sampling of pork has been performed with ˜ 300 analytical data. The organic peroxide content in unirradiated pork has been estimated as (5.4±3.0)X10 -5mol.kg -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˜1 kGy is used, the quantity of peroxide in pork will be 2X10 -4mol.kg -1 (or 4X10 -4 mol.kg -1 for 1 kGy), which is 3.7˜7.4 times greater than the background. If 3 kGy is used to eliminate Samonella, the quantity of peroxides in pork will be 1.3X10 -3mol.kg -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 takes place with G (organic peroxides) value 30.2. Radiation processing dose of braised chicken for shelf-life extension is ˜ 9kGy, organic peroxide content in braised chicken fat is 32.5X10 -4mol.kg -1, which is about 14.7 times greater than average value (2.2X10 -4mol.kg -1) in unirradiated one. Applying peroxide method to qualitatively detect the irradiated food containing fat is satisfactory. Recombining with measuring ESR signal of irradiated bone will cause the method of detection more accurate and perfect.

  13. Demonstration of the Catalytic Decomposition of Hydrogen Peroxide

    NASA Astrophysics Data System (ADS)

    Conklin, Alfred R., Jr.; Kessinger, Angela

    1996-09-01

    Catalytic decomposition is demonstrated by placing hydrogen peroxide solutions in a one liter graduated cylinder and adding soap, food coloring, and potassium iodide. Released oxygen is trapped by the soap producing bubbles. The volume of bubbles is proportional to the concentration of hydrogen peroxide. Chloride and bromide do not cause decomposition. Increased reactant temperature increases the volume of bubbles formed.

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

    NASA Astrophysics Data System (ADS)

    Soderquist, Chuck; Hanson, Brady

    2010-01-01

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

  15. A sacrificial millipede altruistically protects its swarm using a drone blood enzyme, mandelonitrile oxidase

    PubMed Central

    Ishida, Yuko; Kuwahara, Yasumasa; Dadashipour, Mohammad; Ina, Atsutoshi; Yamaguchi, Takuya; Morita, Masashi; Ichiki, Yayoi; Asano, Yasuhisa

    2016-01-01

    Soldiers of some eusocial insects exhibit an altruistic self-destructive defense behavior in emergency situations when attacked by large enemies. The swarm-forming invasive millipede, Chamberlinius hualienensis, which is not classified as eusocial animal, exudes irritant chemicals such as benzoyl cyanide as a defensive secretion. Although it has been thought that this defensive chemical was converted from mandelonitrile, identification of the biocatalyst has remained unidentified for 40 years. Here, we identify the novel blood enzyme, mandelonitrile oxidase (ChuaMOX), which stoichiometrically catalyzes oxygen consumption and synthesis of benzoyl cyanide and hydrogen peroxide from mandelonitrile. Interestingly the enzymatic activity is suppressed at a blood pH of 7, and the enzyme is segregated by membranes of defensive sacs from mandelonitrile which has a pH of 4.6, the optimum pH for ChuaMOX activity. In addition, strong body muscle contractions are necessary for de novo synthesis of benzoyl cyanide. We propose that, to protect its swarm, the sacrificial millipede also applies a self-destructive defense strategy—the endogenous rupturing of the defensive sacs to mix ChuaMOX and mandelonitrile at an optimum pH. Further study of defensive systems in primitive arthropods will pave the way to elucidate the evolution of altruistic defenses in the animal kingdom. PMID:27265180

  16. A sacrificial millipede altruistically protects its swarm using a drone blood enzyme, mandelonitrile oxidase.

    PubMed

    Ishida, Yuko; Kuwahara, Yasumasa; Dadashipour, Mohammad; Ina, Atsutoshi; Yamaguchi, Takuya; Morita, Masashi; Ichiki, Yayoi; Asano, Yasuhisa

    2016-06-06

    Soldiers of some eusocial insects exhibit an altruistic self-destructive defense behavior in emergency situations when attacked by large enemies. The swarm-forming invasive millipede, Chamberlinius hualienensis, which is not classified as eusocial animal, exudes irritant chemicals such as benzoyl cyanide as a defensive secretion. Although it has been thought that this defensive chemical was converted from mandelonitrile, identification of the biocatalyst has remained unidentified for 40 years. Here, we identify the novel blood enzyme, mandelonitrile oxidase (ChuaMOX), which stoichiometrically catalyzes oxygen consumption and synthesis of benzoyl cyanide and hydrogen peroxide from mandelonitrile. Interestingly the enzymatic activity is suppressed at a blood pH of 7, and the enzyme is segregated by membranes of defensive sacs from mandelonitrile which has a pH of 4.6, the optimum pH for ChuaMOX activity. In addition, strong body muscle contractions are necessary for de novo synthesis of benzoyl cyanide. We propose that, to protect its swarm, the sacrificial millipede also applies a self-destructive defense strategy-the endogenous rupturing of the defensive sacs to mix ChuaMOX and mandelonitrile at an optimum pH. Further study of defensive systems in primitive arthropods will pave the way to elucidate the evolution of altruistic defenses in the animal kingdom.

  17. A biosensor for hydrogen peroxide detection based on electronic properties of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Majidi, Roya

    2013-01-01

    Density functional theory has been used to study the effect of hydrogen peroxide on the electronic properties of single walled carbon nanotubes. The metallic and semiconducting carbon nanotubes have been considered in the presence of different number of hydrogen peroxide. The results indicate that hydrogen peroxide has no significant effect on the metallic nanotube and these nanotubes remain to be metallic. In contrast, the electronic properties of the semiconducting nanotubes are so sensitive to hydrogen peroxide. The energy band gap of these nanotubes is decreased by increasing the number of hydrogen peroxide. The electronic sensivity of the carbon nanotubes to hydrogen peroxide opens new insights into developing biosensors based on the single walled carbon nanotubes.

  18. Electrochemical Visualization of Intracellular Hydrogen Peroxide at Single Cells.

    PubMed

    He, Ruiqin; Tang, Huifen; Jiang, Dechen; Chen, Hong-yuan

    2016-02-16

    In this Letter, the electrochemical visualization of hydrogen peroxide inside one cell was achieved first using a comprehensive Au-luminol-microelectrode and electrochemiluminescence. The capillary with a tip opening of 1-2 μm was filled with the mixture of chitosan and luminol, which was coated with the thin layers of polyvinyl chloride/nitrophenyloctyl ether (PVC/NPOE) and gold as the microelectrode. Upon contact with the aqueous hydrogen peroxide, hydrogen peroxide and luminol in contact with the gold layer were oxidized under the positive potential resulting in luminescence for the imaging. Due to the small diameter of the electrode, the microelectrode tip was inserted into one cell and the bright luminescence observed at the tip confirmed the visualization of intracellular hydrogen peroxide. The further coupling of oxidase on the electrode surface could open the field in the electrochemical imaging of intracellular biomolecules at single cells, which benefited the single cell electrochemical detection.

  19. Peroxide Propulsion at the Turn of the Century

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  20. Hydrogen peroxide inhibits iodide uptake and iodine organification in cultured porcine thyroid follicles.

    PubMed

    Fukayama, H; Murakami, S; Nasu, M; Sugawara, M

    1991-01-01

    We investigated the effect of hydrogen peroxide on the process of thyroid hormone formation in a physiologic culture system of porcine thyroid follicles that we recently established. Porcine thyroid follicles cultured in medium containing 1 mU/mL TSH were exposed to 0 to 500 microM hydrogen peroxide in the presence of 0.1 microCi carrier-free Na125 and sodium iodide for 2 h. Iodide uptake and iodine organification were measured in this incubation system. The kinetics of iodide uptake were used to explain the action of hydrogen peroxide. In addition, cAMP content and Na+,K(+)-ATPase activity (an enzyme necessary for iodide uptake) were measured to investigate the mechanism of hydrogen peroxide action. Hydrogen peroxide at concentrations of 100, 200, and 500 microM inhibited iodide uptake in a dose-dependent manner. Iodide organification was inhibited only when the concentration of hydrogen peroxide was greater than 200 microM. The kinetics of iodide uptake indicated that hydrogen peroxide was a noncompetitive inhibitor with iodide. Inhibition of iodide uptake and iodine organification by hydrogen peroxide were not mediated by alteration of cAMP content of Na+,K(+)-ATPase activity, since exposure to even 500 microM hydrogen peroxide did not change these parameters in the follicle when compared with those of control samples. Our results suggest that the iodide transport system in the thyroid follicle is inhibited at 200 microM hydrogen peroxide or greater.

  1. Different Modes of Hydrogen Peroxide Action During Seed Germination

    PubMed Central

    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

  2. SELECTIVE SEPARATION OF URANIUM FROM THORIUM, PROTACTINIUM AND FISSION PRODUCTS BY PEROXIDE DISSOLUTION METHOD

    DOEpatents

    Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

    1959-08-18

    A method is described for separating U/sup 233/ from thorium and fission products. The separation is effected by forming a thorium-nitric acid solution of about 3 pH, adding hydrogen peroxide to precipitate uranium and thorium peroxide, treating the peroxides with sodium hydroxide to selectively precipitate the uranium peroxide, and reacting the separated solution with nitric acid to re- precipitate the uranium peroxide.

  3. Combined effects of microwaves, electron beams and polyfunctional monomers on rubber vulcanization.

    PubMed

    Manaila, Elena; Martin, Diana; Stelescu, Daniela Zuga; Craciun, Gabriela; Ighigeanu, Daniel; Matei, Constantin

    2009-01-01

    This paper presents comparative results obtained by conventional vulcanization with benzoyl peroxide (CV-BP), separate electron beam vulcanization (EB-V) and simultaneous electron beam and microwave vulcanization (EB+MW-V) applied to two kind of rubber samples: EVA (ethylene vinyl acetate) rubber-sample (EVA-sample) and EPDM (ethylene-propylene terpolymer) rubber-sample (EPDM-sample). The EVA-samples contain 61.54% EVA Elvax 260, 30.77% carbon black, 1.85% TAC (triallylcyanurate) polyfunctional monomer and 5.84% filler (zinc oxide, stearic acid, polyethylene glycol and antioxidant). The EPDM-samples contain 61.54% EPDM Nordel 4760, 30.77% carbon black, 1.85% TMPT (trimethylopropane trimethacrylate) polyfunctional monomer and 5.84% filler (zinc oxide, stearic acid, polyethylene glycol and antioxidant). The rubber samples designed for different vulcanization methods were obtained from raw rubber mixtures, as compressed sheets of 2 mm in the polyethylene foils to minimize oxidation. For EB and EB + MW treatments the sheets were cut in rectangular shape 0.15 x 0.15 m2. The physical properties of samples obtained by CV-BP EV-Vand EB + MW-V methods were evaluated by measuring the tearing strength, residual elongation, elongation at break, tensile strength, 300% modulus, 100% modulus, elasticity and hardness. The obtained results demonstrate an improvement of rubber several properties obtained by EB and EB + MW processing as compared to classical procedure using benzoyl peroxide.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Chemistry and biology of ω-3 PUFA peroxidation-derived compounds.

    PubMed

    Wang, Weicang; Yang, Haixia; Johnson, David; Gensler, Catherine; Decker, Eric; Zhang, Guodong

    2017-09-01

    The ω-3 polyunsaturated fatty acids (PUFAs) are among the most popular dietary supplements in the US, but they are chemically unstable and highly prone to lipid peroxidation. Many studies performed in different countries demonstrate that the majority of ω-3 PUFA products on the market are oxidized, suggesting that the resulting ω-3 PUFA peroxidation-derived compounds could be widely consumed by the general public. Therefore, it is of practical importance to understand the effects of these oxidized lipid compounds on human health. In this review, we summarize and discuss the chemical structures and biological activities of ω-3 PUFA peroxidation-derived compounds, and emphasize the importance to better understand the role of lipid peroxidation in biological activities of ω-3 PUFAs. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  7. Reproducing Phenomenology of Peroxidation Kinetics via Model Optimization

    NASA Astrophysics Data System (ADS)

    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.

  8. Hyperbaric oxygen therapy for systemic gas embolism after hydrogen peroxide ingestion.

    PubMed

    Byrne, Brendan; Sherwin, Robert; Courage, Cheryl; Baylor, Alfred; Dolcourt, Bram; Brudzewski, Jacek R; Mosteller, Jeffrey; Wilson, Robert F

    2014-02-01

    Hydrogen peroxide is a commonly available product and its ingestion has been demonstrated to produce in vivo gas bubbles, which can embolize to devastating effect. We report two cases of hydrogen peroxide ingestion with resultant gas embolization, one to the portal system and one cerebral embolus, which were successfully treated with hyperbaric oxygen therapy (HBO), and review the literature. Two individuals presented to our center after unintentional ingestion of concentrated hydrogen peroxide solutions. Symptoms were consistent with portal gas emboli (Patient A) and cerebral gas emboli (Patient B), which were demonstrated on imaging. They were successfully treated with HBO and recovered without event. As demonstrated by both our experience as well as the current literature, HBO has been used to successfully treat gas emboli associated with hydrogen peroxide ingestion. We recommend consideration of HBO in any cases of significant hydrogen peroxide ingestion with a clinical picture compatible with gas emboli. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

    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. Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract.

    PubMed

    Okoko, Tebekeme; Ere, Diepreye

    2012-06-01

    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. 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. 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. 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.

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

    PubMed Central

    Chen, Rui; Zhang, Luzhong; Gao, Jian; Wu, Wei; Hu, Yong; Jiang, Xiqun

    2011-01-01

    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. PMID:21765637

  12. Cathodic electrocatalyst layer for electrochemical generation of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  13. Hydrogen Peroxide Accidents and Incidents: What We Can Learn From History

    NASA Technical Reports Server (NTRS)

    Greene, Ben; Baker, David L.; Frazier, Wayne

    2005-01-01

    Historical accidents and incidents involving hydrogen peroxide are reviewed and presented. These hydrogen peroxide events are associated with storage, transportation, handling, and disposal and they include exposures, fires, and explosions. Understanding the causes and effects of these accident and incident examples may aid personnel currently working with hydrogen peroxide to mitigate and perhaps avoid similar situations. Lessons learned, best practices, and regulatory compliance information related to the cited accidents and incidents are also discussed.

  14. Capillary electrophoresis-electrochemistry microfluidic system for the determination of organic peroxides

    NASA Technical Reports Server (NTRS)

    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.

  15. Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract

    PubMed Central

    Okoko, Tebekeme; Ere, Diepreye

    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. PMID:23569948

  16. Simulated afterburner performance with hydrogen peroxide injection for thrust augmentation

    NASA Technical Reports Server (NTRS)

    Metzler, Allen J; Grobman, Jack S

    1956-01-01

    Combustion performance of three afterburner configurations was evaluated at simulated altitude flight conditions with liquid augmentation to the primary combustor. Afterburner combustion efficiency and stability were better with injection of high-strength hydrogen peroxide than with no injection or with water injection. Improvements were observed in afterburner configurations with and without flameholders and in a short-length afterburner. At a peroxide-air ratio of 0.3, combustion was stable and 85 to 90 percent efficient in all configurations tested. Calculated augmented net-thrust ratios for peroxide injection with afterburning were approximately 60 percent greater than those for water injection.

  17. Tolerance of pentose utilising yeast to hydrogen peroxide-induced oxidative stress.

    PubMed

    Spencer, Jennifer; Phister, Trevor G; Smart, Katherine A; Greetham, Darren

    2014-03-17

    Bioethanol fermentations follow traditional beverage fermentations where the yeast is exposed to adverse conditions such as oxidative stress. Lignocellulosic bioethanol fermentations involve the conversion of pentose and hexose sugars into ethanol. Environmental stress conditions such as osmotic stress and ethanol stress may affect the fermentation performance; however, oxidative stress as a consequence of metabolic output can also occur. However, the effect of oxidative stress on yeast with pentose utilising capabilities has yet to be investigated. Assaying for the effect of hydrogen peroxide-induced oxidative stress on Candida, Pichia and Scheffersomyces spp. has demonstrated that these yeast tolerate hydrogen peroxide-induced oxidative stress in a manner consistent with that demonstrated by Saccharomyces cerevisiae. Pichia guillermondii appears to be more tolerant to hydrogen peroxide-induced oxidative stress when compared to Candida shehatae, Candida succiphila or Scheffersomyces stipitis. Sensitivity to hydrogen peroxide-induced oxidative stress increased in the presence of minimal media; however, addition of amino acids and nucleobases was observed to increase tolerance. In particular adenine increased tolerance and methionine reduced tolerance to hydrogen peroxide-induced oxidative stress.

  18. Tolerance of pentose utilising yeast to hydrogen peroxide-induced oxidative stress

    PubMed Central

    2014-01-01

    Background Bioethanol fermentations follow traditional beverage fermentations where the yeast is exposed to adverse conditions such as oxidative stress. Lignocellulosic bioethanol fermentations involve the conversion of pentose and hexose sugars into ethanol. Environmental stress conditions such as osmotic stress and ethanol stress may affect the fermentation performance; however, oxidative stress as a consequence of metabolic output can also occur. However, the effect of oxidative stress on yeast with pentose utilising capabilities has yet to be investigated. Results Assaying for the effect of hydrogen peroxide-induced oxidative stress on Candida, Pichia and Scheffersomyces spp. has demonstrated that these yeast tolerate hydrogen peroxide-induced oxidative stress in a manner consistent with that demonstrated by Saccharomyces cerevisiae. Pichia guillermondii appears to be more tolerant to hydrogen peroxide-induced oxidative stress when compared to Candida shehatae, Candida succiphila or Scheffersomyces stipitis. Conclusions Sensitivity to hydrogen peroxide-induced oxidative stress increased in the presence of minimal media; however, addition of amino acids and nucleobases was observed to increase tolerance. In particular adenine increased tolerance and methionine reduced tolerance to hydrogen peroxide-induced oxidative stress. PMID:24636079

  19. Peroxide as a Novel Treatment for Ecchymoses

    PubMed Central

    Sroa, Novie; Campbell, Shannon M.; Bechtel, Mark A.; Mitch Opremcak, E.

    2010-01-01

    Ecchymoses, commonly known as bruises, frequently occur after injury to the skin causes extravasation of red blood cells into interstitial tissue. This extravasation can lead to an inflammatory cascade. The case report presented details one patient who displayed rapid improvement in the pain and appearance of a partially treated bruise on her thigh after an eight-hour application of hydrogen peroxide 15% carbamide gel under occlusion. Hydrogen peroxide 15% carbamide gel may represent a novel treatment for ecchymoses. This potential new treatment for bruises needs to be studied further to detail its adverse effects, safety profile, and efficacy profile. PMID:21103315

  20. [Cerebral vasospasm and lipid peroxidation--lipid peroxides in the cerebrospinal fluid after subarachnoid hemorrhage].

    PubMed

    Sasaki, T; Asano, T; Takakura, K; Sano, K; Nakamura, T; Suzuki, N; Imabayashi, S; Ishikawa, Y

    1982-12-01

    The relationship between lipid peroxides in cerebrospinal fluid (CSF) and the occurrence of cerebral vasospasm following subarachnoid hemorrhage (SAH) was evaluated by analyzing CSF with high-performance liquid chromatography (HPLC) and gas chromatography mass spectrometry (GC-MS). Hydroperoxy eicosatetraenoic acids (HPETEs) and hydroxy eicosatetraenoic acids (HETEs) were synthesized by the treatment of arachidonic acid with hydrogen peroxide and cupric chloride. The retention time of these HPETEs and HETEs were determined on HPLC. The position of oxydation occurred was determined after methylation, reduction and trimethyl silylation using GC-MS. Thus the elucidation of positional isomers of HPETEs and HETEs was made possible by the retention time on HPLC. The supernant of CSF after SAH was adjusted to pH 3.0 and then absorbed to octadecyl silyl silica column. The eluted fraction with 15% ethanol-water from octadecyl silyl silica column was analyzed by HPLC detecting at 238 nm. No peak was observed on HPLC at the region of HPETEs and HETEs in the CSF obtained from healthy person. In SAH patients, several peaks were recognized in accordance with the occurrence of cerebral vasospasm. One of the peaks was identified as 5-HETE by HPLC and GC-MS. In 10 SAH patients, semi-quantitative analysis of 5-HETE in the CSF was performed by measuring the height of the peak identified as 5-HETE on HPLC. The close correlation was recognized between the occurrence of cerebral vasospasm and the appearance of 5-HETE in the CSF. The results of the present study suggest that lipid peroxidation is involved in the pathogenesis of chronic vasospasm after SAH.

  1. Discoloration of titanium alloy in acidic saline solutions with peroxide.

    PubMed

    Takemoto, Shinji; Hattori, Masayuki; Yoshinari, Masao; Kawada, Eiji; Oda, Yutaka

    2013-01-01

    The objective of this study was to compare corrosion behavior in several titanium alloys with immersion in acidulated saline solutions containing hydrogen peroxide. Seven types of titanium alloy were immersed in saline solutions with varying levels of pH and hydrogen peroxide content, and resulting differences in color and release of metallic elements determined in each alloy. Some alloys were characterized using Auger electron spectroscopy. Ti-55Ni alloy showed a high level of dissolution and difference in color. With immersion in solution containing hydrogen peroxide at pH 4, the other alloys showed a marked difference in color but a low level of dissolution. The formation of a thick oxide film was observed in commercially pure titanium showing discoloration. The results suggest that discoloration in titanium alloys immersed in hydrogen peroxide-containing acidulated solutions is caused by an increase in the thickness of this oxide film, whereas discoloration of Ti-55Ni is caused by corrosion.

  2. Peroxide-modified titanium dioxide: a chemical analog of putative Martian soil oxidants

    NASA Technical Reports Server (NTRS)

    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

  3. Alternative bleaching methods for Cheddar cheese whey.

    PubMed

    Kang, E J; Smith, T J; Drake, M A

    2012-07-01

    Residual annatto colorant (norbixin) in fluid Cheddar cheese whey can be bleached. The 2 approved chemical bleaching agents for whey, hydrogen peroxide (HP) and benzoyl peroxide (BP), negatively impact the flavor of dried whey protein. The objective of this study was to evaluate alternative methods for bleaching liquid whey: ultraviolet radiation (UV), acid-activated bentonite (BT), and ozone (OZ). Colored Cheddar cheese whey was manufactured followed by pasteurization and fat separation. Liquid whey was subjected to one of 5 treatments: control (CT) (no bleaching; 50 °C, 1 h), HP (250 mg/kg; 50 °C, 1 h), UV (1 min exposure; 50 °C), BT (0.5% w/w; 50 °C, 1 h), or OZ (2.2g/h, 50 °C, 1 h). The treated whey was then ultrafiltered, diafiltered, and spray-dried to 80% whey protein concentrate (WPC80). The entire experiment was replicated 3 times. Color (norbixin extraction and measurement), descriptive sensory, and instrumental volatile analyses were conducted on WPC80. Norbixin elimination was 28%, 79%, 39%, and 15% for HP, BT, UV, and OZ treatments, respectively. WPC80 from bleached whey, regardless of bleaching agent, had lower sweet aromatic and cooked/milky flavors compared to unbleached CT (P < 0.05). The HP and BT WPC80 had higher fatty flavor compared to the CT WPC80 (P < 0.05), and the UV and OZ WPC80 had distinct mushroom/burnt and animal flavors. Volatile compound results were consistent with sensory results and confirmed higher relative abundances of volatile aldehydes in UV, HP, and OZ WPC80 compared to CT and BT WPC80. Based on bleaching efficacy and flavor, BT may be an alternative to chemical bleaching of fluid whey. The 2 approved chemical bleaching agents for whey, hydrogen peroxide (HP) and benzoyl peroxide (BP), negatively impact flavor of dried whey protein, and restrictions on these agents are increasing. This study evaluated 3 alternatives to chemical bleaching of fluid whey: UV radiation, ozone, and bentonite. © 2012 Institute of Food

  4. Crankshaft motion in a highly congested bis(triarylmethyl)peroxide.

    PubMed

    Khuong, Tinh-Alfredo V; Zepeda, Gerardo; Sanrame, Carlos N; Dang, Hung; Bartberger, Michael D; Houk, K N; Garcia-Garibay, Miguel A

    2004-11-17

    Crankshaft motion has been proposed in the solid state for molecular fragments consisting of three or more rotors linked by single bonds, whereby the two terminal rotors are static and the internal rotors experience circular motion. Bis-[tri-(3,5-di-tert-butyl)phenylmethyl]-peroxide 2 was tested as a model in search of crankshaft motion at the molecular level. In the case of peroxide 2, the bulky trityl groups may be viewed as the external static rotors, while the two peroxide oxygens can undergo the sought after internal rotation. Evidence for this process in the case of peroxide 2 was obtained from conformational dynamics determined by variable-temperature (13)C and (1)H NMR between 190 and 375 K in toluene-d(8). Detailed spectral assignments for the interpretation of two coalescence processes were based on a correlation between NMR spectra obtained in solution at low temperature, in the solid state by (13)C CPMAS NMR, and by GIAO calculations based on a B3LYP/6-31G structure of 2 obtained from its X-ray coordinates as the input. Evidence supporting crankshaft rotation rather than slippage of the trityl groups was obtained from molecular mechanics calculations.

  5. Hydrogen peroxide fuels aging, inflammation, cancer metabolism and metastasis

    PubMed Central

    Martinez-Outschoorn, Ubaldo E; Lin, Zhao; Pavlides, Stephanos; Whitaker-Menezes, Diana; Pestell, Richard G; Howell, Anthony

    2011-01-01

    In 1889, Dr. Stephen Paget proposed the “seed and soil” hypothesis, which states that cancer cells (the seeds) need the proper microenvironment (the soil) for them to grow, spread and metastasize systemically. In this hypothesis, Dr. Paget rightfully recognized that the tumor microenvironment has an important role to play in cancer progression and metastasis. In this regard, a series of recent studies have elegantly shown that the production of hydrogen peroxide, by both cancer cells and cancer-associated fibroblasts, may provide the necessary “fertilizer,” by driving accelerated aging, DNA damage, inflammation and cancer metabolism, in the tumor microenvironment. By secreting hydrogen peroxide, cancer cells and fibroblasts are mimicking the behavior of immune cells (macrophages/neutrophils), driving local and systemic inflammation, via the innate immune response (NFκB). Thus, we should consider using various therapeutic strategies (such as catalase and/or other antioxidants) to neutralize the production of cancer-associated hydrogen peroxide, thereby preventing tumor-stroma co-evolution and metastasis. The implications of these findings for overcoming chemo-resistance in cancer cells are also discussed in the context of hydrogen peroxide production and cancer metabolism. PMID:21734470

  6. Selective electrochemical generation of hydrogen peroxide from water oxidation

    DOE PAGES

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; Norskov, Jens K.

    2015-10-08

    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, wemore » show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e– water oxidation to H 2O 2 and the 4e– oxidation to O 2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO 2, can activate hydrogen peroxide evolution. Furthermore, we present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H 2O 2 evolution selectively.« less

  7. Distillation Kinetics of Solid Mixtures of Hydrogen Peroxide and Water and the Isolation of Pure Hydrogen Peroxide in Ultrahigh Vacuum

    NASA Technical Reports Server (NTRS)

    Teolis, B. D.; Baragiola, R. A.

    2006-01-01

    We present results of the growth of thin films of crystalline H2O2 and H2O2.2H2O (dihydrate) in ultrahigh vacuum by distilling an aqueous solution of hydrogen peroxide. We traced the process using infrared reflectance spectroscopy, mass loss on a quartz crystal microbalance, and in a few cases ultraviolet-visible reflectance. We find that the different crystalline phases-water, dihydrate, and hydrogen peroxide-have very different sublimation rates, making distillation efficient to isolate the less volatile component, crystalline H2O2.

  8. Hydrogen Peroxide Sensing and Signaling by Protein Kinases in the Cardiovascular System

    PubMed Central

    Burgoyne, Joseph R.; Oka, Shin-ichi; Ale-Agha, Niloofar

    2013-01-01

    Abstract Significance: Oxidants were once principally considered perpetrators of injury and disease. However, this has become an antiquated view, with cumulative evidence showing that the oxidant hydrogen peroxide serves as a signaling molecule. Hydrogen peroxide carries vital information about the redox state of the cell and is crucial for homeostatic regulation during health and adaptation to stress. Recent Advances: In this review, we examine the contemporary concepts for how hydrogen peroxide is sensed and transduced into a biological response by introducing post-translational oxidative modifications on select proteins. Oxidant sensing and signaling by kinases are of particular importance as they integrate oxidant signals into phospho-regulated pathways. We focus on CAMKII, PKA, and PKG, kinases whose redox regulation has notable impact on cardiovascular function. Critical Issues: In addition, we examine the mechanism for regulating intracellular hydrogen peroxide, considering the net concentrations that may accumulate. The effects of endogenously generated oxidants are often modeled by applying exogenous hydrogen peroxide to cells or tissues. Here we consider whether model systems exposed to exogenous hydrogen peroxide have relevance to systems where the oxidant is generated endogenously, and if so, what concentration can be justified in terms of relevance to health and disease. Future Directions: Improving our understanding of hydrogen peroxide signaling and the sensor proteins that it can modify will help us develop new strategies to regulate intracellular signaling to prevent disease. Antioxid. Redox Signal. 18, 1042–1052. PMID:22867279

  9. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 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 all...

  10. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 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 all...

  11. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 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 all...

  12. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    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 all...

  13. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 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 all...

  14. BASIC PEROXIDE PRECIPITATION METHOD OF SEPARATING PLUTONIUM FROM CONTAMINANTS

    DOEpatents

    Seaborg, G.T.; Perlman, I.

    1959-02-10

    A process is described for the separation from each other of uranyl values, tetravalent plutonium values and fission products contained in an aqueous acidic solution. First the pH of the solution is adjusted to between 2.5 and 8 and hydrogen peroxide is then added to the solution causing precipitation of uranium peroxide which carries any plutonium values present, while the fission products remain in solution. Separation of the uranium and plutonium values is then effected by dissolving the peroxide precipitate in an acidic solution and incorporating a second carrier precipitate, selective for plutonium. The plutonium values are thus carried from the solution while the uranium remains flissolved. The second carrier precipitate may be selected from among the group consisting of rare earth fluorides, and oxalates, zirconium phosphate, and bismuth lihosphate.

  15. Peroxide reduction by a metal-dependent catalase in Nostoc punctiforme (cyanobacteria).

    PubMed

    Hudek, L; Torriero, A A J; Michalczyk, A A; Neilan, B A; Ackland, M L; Bräu, Lambert

    2017-05-01

    This study investigated the role of a novel metal-dependent catalase (Npun_R4582) that reduces hydrogen peroxide in the cyanobacterium Nostoc punctiforme. Quantitative real-time PCR showed that npun_R4582 relative mRNA levels were upregulated by over 16-fold in cells treated with either 2 μM added Co, 0.5 μM added Cu, 500 μM Mn, 1 μM Ni, or 18 μM Zn. For cells treated with 60 μM H 2 O 2 , no significant alteration in Npun_R4582 relative mRNA levels was detected, while in cells treated with Co, Cu, Mn, Ni, or Zn and 60 μM peroxide, relative mRNA levels were generally above control or peroxide only treated cells. Disruption or overexpression of npun_R4582 altered sensitivity to cells exposed to 60 μM H 2 O 2 and metals for treatments beyond the highest viable concentrations, or in a mixed metal solution for Npun_R4582 - cells. Moreover, overexpression of npun_R4582 increased cellular peroxidase activity in comparison with wild-type and Npun_R4582 - cells, and reduced peroxide levels by over 50%. The addition of cobalt, manganese, nickel, and zinc increased the capacity of Npun_R4582 to reduce the rate or total levels of peroxide produced by cells growing under photooxidative conditions. The work presented confirms the function of NpunR4582 as a catalase and provides insights as to how cells reduce potentially lethal peroxide levels produced by photosynthesis. The findings also show how trace elements play crucial roles as enzymatic cofactors and how the role of Npun_R4582 in hydrogen peroxide breakdown is dependent on the type of metal and the level available to cells.

  16. Passive micromixer for luminol-peroxide chemiluminescence detection.

    PubMed

    Lok, Khoi Seng; Kwok, Yien Chian; Nguyen, Nam-Trung

    2011-06-21

    This paper reports a microchip with an integrated passive micromixer based on chaotic advection. The micromixer with staggered herringbone structures was used for luminol-peroxide chemiluminescence detection. The micromixer was examined to assess its suitability for chemiluminescence reaction. The relationship between the flow rate and the location of maximum chemiluminescence intensity was investigated. The light intensity was detected using an optical fiber attached along the mixing channel and a photon detector. A linear correlation between chemiluminescence intensity and the concentration of cobalt(ii) ions or hydrogen peroxide was observed. This microchip has a potential application in environmental monitoring for industries involved in heavy metals and in medical diagnostics.

  17. Effect of N-benzoyl-D-phenylalanine and metformin on carbohydrate metabolic enzymes in neonatal streptozotocin diabetic rats.

    PubMed

    Ashokkumar, Natarajan; Pari, Leelavinothan

    2005-01-01

    The effect of N-benzoyl-D-phenylalanine (NBDP) and metformin was studied on the activities of carbohydrate metabolic enzymes in neonatal streptozotocin (nSTZ) non-insulin-dependent diabetic rats. To induce non-insulin-dependent diabetes mellitus (NIDDM), single dose injection of streptozotocin (STZ; 100 mg/kg body weight; i.p.) was given to 2-day old rats. After 10-12 weeks, rats weighing >150 g were selected for screening in NIDDM model, they were checked for fasting blood glucose concentrations to conform the status of NIDDM. NBDP (50,100 and 200 mg/kg body weight) was administered orally for 6 weeks into the confirmed diabetic rats. The activities of gluconeogenic enzymes were significantly increased, whereas the activities of hexokinase and glucose-6-phosphate dehydrogenase were significantly decreased in nSTZ diabetic rats. Both NBDP and metformin were able to restore the altered enzyme activities to almost control concentrations. Combination treatment was more effective than either drug alone. The administration of NBDP along with metformin to nSTZ diabetic rats normalizes blood glucose and causes marked improvement of altered carbohydrate metabolic enzymes during diabetes.

  18. 21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... agent in bottled water. (b) Hydrogen peroxide meets the specifications of the “Food Chemicals Codex... information on the availability of this material at NARA, call 202-741-6030 or go to: http://www.archives.gov... exceed 17 micrograms per kilogram in the treated bottled water, and the amount of hydrogen peroxide will...

  19. [The origin of hydrogen peroxide in oral cavity and its role in oral microecology balance].

    PubMed

    Keke, Zhang; Xuedong, Zhou; Xin, Xu

    2017-04-01

    Hydrogen peroxide, an important antimicrobial agent in oral cavity, plays a significant role in the balance of oral microecology. At the early stage of biofilm formation, about 80% of the detected initial colonizers belong to the genus Streptococcus. These oral streptococci use different oxidase to produce hydrogen peroxide. Recent studies showed that the produced hydrogen peroxide plays a critical role in modulating oral microecology. Hydrogen peroxide modulates biofilm development attributed to its growth inhibitory nature. Hydrogen peroxide production is closely associated with extracellular DNA(eDNA) release from microbe and the development of its competent cell which are critical for biofilm development and also serves as source for horizontal gene transfer. Microbe also can reduce the damage to themselves through several detoxification mechanisms. Moreover, hydrogen peroxide is also involved in the regulation of interactions between oral microorganisms and host. Taken together, hydrogen peroxide is an imperative ecological factor that contributes to the microbial equilibrium in the oral cavity. Here we will give a brief review of both the origin and the function in the oral microecology balance of hydrogen peroxide.

  20. Sodium Borohydride/Hydrogen Peroxide Fuel Cells For Space Application

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Deelo, M. E.; Narayanan, S. R.

    2006-01-01

    This viewgraph presentation examines Sodium Borohydride and Hydrogen Peroxide Fuel Cells as they are applied to space applications. The topics include: 1) Motivation; 2) The Sodium Borohydride Fuel Cell; 3) Sodium Borohydride Fuel Cell Test Stands; 4) Fuel Cell Comparisons; 5) MEA Performance; 6) Anode Polarization; and 7) Electrode Analysis. The benefits of hydrogen peroxide as an oxidant and benefits of sodium borohydride as a fuel are also addressed.

  1. Material Demand Studies: Materials Sorption of Vaporized Hydrogen Peroxide

    DTIC Science & Technology

    2010-06-01

    SORPTION OF VAPORIZED HYDROGEN PEROXIDE Lawrence R. Procell Zoe A. Hess David G. Gehring Joseph T. Lynn Philip W. Bartram Teri Lalain RESEARCH AND...2010 2. REPORT TYPE Final 3. DATES COVERED (From - To) Nov 2003 - Jul 2005 4. TITLE AND SUBTITLE Material Demand Studies: Materials Sorption of...of office surfaces 33 \\i MATERIAL DEMAND STUDIES: MATERIALS SORPTION OF VAPORIZED HYDROGEN PEROXIDE 1. BACKGROUND The Material Demand effort was

  2. Hydrogen peroxide as a fungicide for fish culture

    USGS Publications Warehouse

    Dawson, V.K.; Rach, J.J.; Schreier, Theresa M.

    1994-01-01

    Antifungal agents are needed to maintain healthy stocks of fish in the intensive culture systems currently employed in fish hatcheries. Malachite green has been the most widely used antifungal agent; however, its potential for producing teratology in animals and fish precludes further use in fish culture. Preliminary studies at the National Fisheries Research Center, La Crosse, WI, USA (La Crosse Center) indicate that hydrogen peroxide is effective for control of Saprolegnia sp. fungus on incubating eggs of rainbow trout. It is also effective against a wide variety of other organisms such as bacteria, yeasts, viruses, and spores, and has been proposed as a treatment for sea lice on salmon. Hydrogen peroxide and its primary decomposition products, oxygen and water, are not systemic poisons and are considered environmentally compatible. In response to a petition from the La Crosse Center, the U.S. Food and Drug Administration (FDA) recently classified hydrogen peroxide as a 'low regulatory priority' when used for control of fungus on fish and fish eggs. Preliminary tests conducted at the La Crosse Center suggest that prophylactic treatments of 250 to 500 ppm (based on 100% active ingredient) for 15 minutes every other day will inhibit fungal infections on healthy rainbow trout (Oncorhynchus mykiss) eggs. This treatment regime also seems to inhibit fungal development and increase hatching success among infected eggs. Efficacy and safety of hydrogen peroxide as a fungicide for fish are currently being evaluated.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  4. Glycoprotein changes in non-insulin dependent diabetic rats: effect of N-benzoyl-D-phenylalanine and metformin.

    PubMed

    Pari, Leelavinothan; Ashokkumar, Natarajan

    2006-01-01

    The effect of N-benzoyl-D-phenylalanine (NBDP) and metformin on neonatal streptozotocin (nSTZ) induced diabetes has been studied on plasma and tissue glycoproteins. In some pathological conditions, such as cancer, rheumatoid arthritis and diabetes, there is an abnormal glycosylation of acute phase serum proteins. As most serum proteins are produced in the liver, we have examined glycoprotein metabolism in diabetic condition. To induce non-insulin-dependent diabetes mellitus (NIDDM) a single dose of streptozotocin (100 mg/kg body weight) was injected into two day old rats. After 10-12 weeks, rats weighing above 150 g were selected for NIDDM model. In these rat, blood glucose and plasma glycoproteins were significantly increased whereas plasma insulin was significantly decreased. There was a significant decrease in the level of sialic acid and elevated levels of hexose, hexosamine and fucose in tissues. Oral administration of NBDP and metformin to diabetic rats decreased blood glucose and plasma glycoproteins. Plasma insulin and tissue sialic acid were increased whereas tissue concentrations of hexose, hexosamine and fucose were near normal. Our study suggests that NBDP and metformin possess a significant beneficial effect on glycoproteins in addition to their antidiabetic effect.

  5. High levels of hydrogen peroxide in overnight tooth-whitening formulas: effects on enamel and pulp.

    PubMed

    Pugh, George; Zaidel, Lynette; Lin, Nora; Stranick, Michael; Bagley, Daniel

    2005-01-01

    Limited data are available to assess the safety of high levels of hydrogen peroxide in overnight tooth-whitening formulas. The purpose of this study was to assess the effects of hydrogen peroxide on enamel microhardness, pulp penetration, and enamel morphology. Colgate Platinum Professional Overnight Whitening System (Colgate Oral Pharmaceuticals, Inc., Canton, MA, USA) (10% carbamide peroxide, equivalent to 3.5% hydrogen peroxide) was compared with two prototype formulations containing either 7.0% or 12.0% hydrogen peroxide. In the pulp chamber studies, human extracted teeth were exposed to 3.5%, 7.0%, or 12.0% hydrogen peroxide for 30 minutes, 4 hours, or 7 hours. Microhardness, electron spectroscopy for chemical analysis, and atomic force microscopy evaluations were made from enamel blocks cut from human extracted molars. The enamel blocks were evaluated following 14 7-hour treatments (98 h total). At 7 hours' post-treatment, hydrogen peroxide penetrated the pulp chamber at 23.12 +/- 10.09, 24.58 +/- 6.90, and 26.39 +/- 5.43 microg for 3.5%, 7.0%, and 12.0% hydrogen peroxide, respectively. With regard to enamel morphology, pulp penetration, microhardness, and elemental composition, no statistically significant differences were observed between treatment groups following 98 hours of treatment. Hydrogen peroxide does not adversely affect enamel morphology or microhardness. The levels recovered in pulp indicate that hydrogen peroxide is not expected to inhibit pulpal enzymes. Overnight tray products containing levels of hydrogen peroxide of 3.5%, 7.0%, and 12.0% are not expected to adversely affect the enamel or pulpal enzymes. Additional safety studies are needed to assess the potential for tooth sensitivity and gingival irritation.

  6. Patch-test reactions to plastic and glue allergens.

    PubMed

    Kanerva, L; Jolanki, R; Alanko, K; Estlander, T

    1999-07-01

    Plastics and glues are common causes of occupational dermatoses, but only few reports have dealt with patch-test reactions caused by plastic and glue allergens. Patients exposed to plastics and remitted to an occupational dermatology clinic, were patch-tested with 50-53 plastic and glue allergens during a 6-year period. Conventional patch-test techniques were used. The most common causes of allergic patch-test reactions in 360 patients were novolac epoxy resin (5.1%), phenol formaldehyde resin (3.1%), 4-tert-butylcatechol (2.6%), phenyl glycidyl ether (2.6%), diaminodiphenyl methane (2.2%), benzoyl peroxide (2.2%), hexamethylene tetramine (2.0%) and o-cresyl glycidyl ether (1.6%). The allergens that most often elicited irritant patch-test reactions were: benzoyl peroxide (9.5%), abitol alcohol (3.6%), hydroquinone (3.1%), acid-catalyzed phenol formaldehyde resin (2.5%) and toluene diisocyanate (1.9%). Twenty-six out of 53 chemicals caused no allergic reaction during the 6-year period. Plastic allergens in the standard series provoked allergic reactions with formaldehyde (5.8%), diglycidyl ether of bisphenol A (3.2%), 4-tert-butylphenol-formaldehyde-resin (1.1%), toluene sulphonamide formaldehyde-resin (1.1%) and triethylenglycol diacrylate (0.4%). Although half of the plastic chemicals gave no allergic patch-test reactions during a 6-year period, with unusual allergens this low yield needs to be accepted, because otherwise rare allergies will not be detected. Also a negative reaction has diagnostic value.

  7. Which acne treatment has the best influence on health-related quality of life? Literature review by the European Academy of Dermatology and Venereology Task Force on Quality of Life and Patient Oriented Outcomes.

    PubMed

    Chernyshov, P V; Tomas-Aragones, L; Manolache, L; Svensson, A; Marron, S E; Evers, A W M; Bettoli, V; Jemec, G B; Szepietowski, J C

    2018-05-05

    According to results of a recent literature search performed by the European Academy of Dermatology and Venereology (EADV) Task Forces (TF) on Quality of Life and Patient Oriented Outcomes (QoL and PO) and Acne, Rosacea and Hidradenitis Suppurativa (ARHS) most of publications where health-related (HR) QoL of acne patients was studied were clinical trials. Members of the EADV TF on QoL and PO decided to detect which acne treatment has the best influence on HRQoL of acne patients. A new literature search was organized to find publications on acne treatment where the HRQoL of patients was assessed as an outcome measure. From 186 papers with HRQoL assessment 37 papers were included for further analysis. Our results revealed that oral isotretinoin had the best influence on HRQoL of acne patients. Several other treatment methods also showed good effects on the HRQoL of acne patients. Oral isotretinoin and norethindrone acetate/ethinyl estradiol, topical clindamycin phosphate/benzoyl peroxide and adapalene/benzoyl peroxide showed significantly better effect on HRQoL than placebo. There is limited number of the high-quality studies on acne treatment where HRQoL were assessed. Dermatology-specific and acne-specific instruments showed much better sensitivity to successful therapeutic intervention than generic HRQoL instruments. The most frequently used HRQoL instrument was the DLQI questionnaire. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  8. Continuous millimeter-wave radiation has no effect on lipid peroxidation in liposomes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Logani, M.K.; Ziskin, M.C.

    1996-02-01

    The effect of millimeter waves on lipid peroxidation was studied in the presence and absence of melanin. Irradiation of liposomes with continuous millimeter electromagnetic waves at frequencies of 53.6, 61.2 and 78.2 GHz and incident power densities of 10, 1 and 500 mW/cm{sup 2}, respectively, did not show an enhancement in the formation of lipid peroxides compared to unirradiated samples. Liposomes exposed to 254 nm UVC radiation at 0.32 mW/cm{sup 2} and 302 nm UVB radiation at 1.12 mW/cm{sup 2} served as positive controls. No increment in the formation of lipid peroxides was observed when irradiation of liposomes was carriedmore » out in the presence of ADP-Fe{sup +3} and EDTA-Fe{sup +3}. Direct irradiation of melanin with millimeter waves did not exhibit an increased formation of superoxide or hydrogen peroxide. The present results indicate that millimeter waves of the above frequencies and intensities do not cause lipid peroxidation in liposomal membranes. 19 refs., 2 figs., 1 tab.« less

  9. Chemical reactions in perfume ageing.

    PubMed

    Blakeway, J M; Frey, M L; Lacroix, S; Salerno, M S

    1987-10-01

    Summary The interactions between a typical range of perfume materials, alcohol, water, air, elevated temperatures and daylight have been studied. The changes of composition, acidity, peroxide content and the formation of new molecules were followed. The stabilizing effects of UV absorbers, antioxidants and sequestering agents were examined; - the formation of acid reaction products was accelerated by air, temperature, daylight and the presence of natural products; - peroxide formation was accelerated by heat and light and the presence of air; as the acidity increased, the peroxides decomposed; - the acetalization of other aldehydes was accelerated by temperature and daylight and the presence of natural products up to 40% of certain aldehydes may be converted into acetals after 3 months at 37 degrees C; - many stereoisomerizations occur, e.g., transisoeugenol is converted up to 10% into the cis isomer after 3 months at 37 degrees C and 58% in daylight; - evaluation of antioxidants UV absorbers and sequestering agents showed a significant protection against deterioration only by EDTA dipotassium salt; - ethanol was converted into acetaldehyde and its diethylacetal by peroxides present and formed on ageing up to 0.08%. Natural products accelerated this formation; - the reaction between benzoyl peroxide and ethanol was shown to yield up to 63% of acetaldehyde+diethyl acetal whilst di-t-butyl peroxide gave only 23% under the same conditions. These results go some way to explaining odour changes in perfume ageing.

  10. An upper limit for stratospheric hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Traub, W. A.

    1984-01-01

    It has been postulated that hydrogen peroxide is important in stratospheric chemistry as a reservoir and sink for odd hydrogen species, and for its ability to interconvert them. The present investigation is concerned with an altitude dependent upper limit curve for stratospheric hydrogen peroxide, taking into account an altitude range from 21.5 to 38.0 km for January 23, 1983. The data employed are from balloon flight No. 1316-P, launched from the National Scientific Balloon Facility (NSBF) in Palestine, Texas. The obtained upper limit curve lies substantially below the data reported by Waters et al. (1981), even though the results are from the same latitude and are both wintertime measurements.

  11. Combined n-benzoyl-d-phenylalanine and metformin treatment reverses changes in the fatty acid composition of streptozotocin diabetic rats.

    PubMed

    Kumar, Natarajan Ashok; Pari, Leelavinothan

    2006-01-01

    The present investigation was carried out to evaluate the effect of N-benzoyl-D-phenylalanine (NBDP) and metformin on blood glucose, plasma insulin, and on the fatty acid composition of total lipids in the livers and kidneys of control and experimental diabetic rats. When compared with nondiabetic control rats, neonatal streptozotocin (nSTZ) diabetic rats showed a significant increase in blood glucose and decreased plasma insulin. Analysis of fatty acids revealed a significant increase in the concentration of palmitic, stearic, and oleic acids in liver and kidney, whereas linolenic and arachidonic acids were significantly decreased. In diabetic rats, the oral administration of combined NBDP/metformin for 6 wk decreased the high concentrations of palmitic, stearic, and oleic acids and elevated the low levels of linolenic and arachidonic acids. The results suggest that the NBDP/metformin combination exhibits both antidiabetic and antihyperlipidemic effects in nSTZ diabetic rats and prevents the fatty acid changes produced during diabetes.

  12. Glycyl-alanyl-histidine protects PC12 cells against hydrogen peroxide toxicity.

    PubMed

    Shimura, Hideki; Tanaka, Ryota; Shimada, Yoshiaki; Yamashiro, Kazuo; Hattori, Nobutaka; Urabe, Takao

    2017-11-22

    Peptides with cytoprotective functions, including antioxidants and anti-infectives, could be useful therapeutics. Carnosine, β-alanine-histidine, is a dipeptide with anti-oxidant properties. Tripeptides of Ala-His-Lys, Pro-His-His, or Tyr-His-Tyr are also of interest in this respect. We synthesized several histidine-containing peptides including glycine or alanine, and tested their cytoprotective effects on hydrogen peroxide toxicity for PC12 cells. Of all these peptides (Gly-His-His, Ala-His-His, Ala-His-Ala, Ala-Ala-His, Ala-Gly-His, Gly-Ala-His (GAH), Ala-His-Gly, His-Ala-Gly, His-His-His, Gly-His-Ala, and Gly-Gly-His), GAH was found to have the strongest cytoprotective activity. GAH decreased lactate dehydrogenase (LDH) leakage, apoptosis, morphological changes, and nuclear membrane permeability changes against hydrogen peroxide toxicity in PC12 cells. The cytoprotective activity of GAH was superior to that of carnosine against hydrogen peroxide toxicity in PC12 cells. GAH also protected PC12 cells against damage caused by actinomycin D and staurosporine. Additionally, it was found that GAH also protected SH-SY5Y and Jurkat cells from damage caused by hydrogen peroxide, as assessed by LDH leakage. Thus, a novel tripeptide, GAH, has been identified as having broad cytoprotective effects against hydrogen peroxide-induced cell damage.

  13. Investigation of flavonoid influence on peroxidation processes intensity in the blood

    NASA Astrophysics Data System (ADS)

    Navolokin, N. A.; Mudrak, D. A.; Plastun, I. L.; Bucharskaya, A. B.; Agandeeva, K. E.; Ivlichev, A. V.; Tychina, S. A.; Afanasyeva, G. A.; Polukonova, N. V.; Maslyakova, G. N.

    2017-03-01

    Influence of flavonoids on the intensity of peroxidation processes in the blood is investigated by numerical modeling and by experiment in vivo. As an example we consider the effects of flavonoid-containing extract of Helichrysum arenarium L. with antitumor activity on serum of rats with transplanted liver cancer PC-1. It was found that the content of malondialdehyde, lipid hydroperoxides and average mass molecules were decreased in animals with transplanted liver cancer after intramuscular and oral administration of Helichrysum arenarium L extract in a dose of 1000 mg/mL. The extract reduces the intensity of lipid peroxidation processes in animals. The compound formation possibility of flavonoids and products of lipid peroxidation is investigated by numerical simulations. Using the density functional theory method of molecular modeling, we analyze hydrogen bonds formation and their influence on IR - spectra and structure of molecular complex which is formed due to interaction between flavonoids and products of lipid peroxidation processes on example of naringine and malondialdehyde. We have found that naringine can form a steady molecular complex with malondialdehyde by hydrogen bonds formation. Thus, the application of Helichrysum arenarium L. extract for suppression processes of lipid peroxidation and activation of enzymatic and non-enzymatic antioxidant systems is promising.

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

    NASA Technical Reports Server (NTRS)

    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.

  15. APPARATUS AND METHOD FOR TREATING POLLUTANTS IN A GAS USING HYDROGEN PEROXIDE AND UV LIGHT

    NASA Technical Reports Server (NTRS)

    Cooper, Charles David (Inventor); Clauseu, 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 there between. 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.

  16. Neglected aspects in the management of acne.

    PubMed Central

    Gordon, B

    1985-01-01

    Acne is the result of excessive grease on the skin. The successful treatment of acne depends essentially on the degreasing of the skin to an extent which produces peeling, which is the observable index of adequate treatment. The use of antibiotics is supplementary to degreasing and peeling. Degreasing is best achieved by thrice daily washing with Neutrogena acne cleansing soap, followed by the application of a benzoyl peroxide preparation of a suitable strength. If necessary, further degreasing can be achieved by cleansing with isopropyl alcohol after washing with the Neutrogena soap. PMID:2941579

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  18. Effects of Martian Surface Materials on the Thermal Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Archer, P. D., Jr.

    2017-01-01

    While hydrogen peroxide (H2O2) has been detected in the martian atmosphere, it has not been detected in surface materials. Since the Viking lander mission, we have sent instruments to Mars with the capability to detect H2O2. The Sample Analysis at Mars (SAM) instrument onboard the Curiosity Rover and Thermal and Evolved Gas Analyzer (TEGA) instrument on the Phoenix lander both detected water and oxygen releases from analyzed sediments but whether or not peroxide could be the source of these gases has not been investigated. We are investigating the possible presence of H2O2 in martian materials by analyzing Mars-relevant minerals that have been mixed with hydrogen peroxide using lab instruments configured as analogs to Mars mission instruments. The object of this research is to use lab instruments to find the effects of Mars analog minerals on hydrogen peroxide gas release temperatures, specifically gas releases of water and oxygen and also determine the effect of the peroxide on the minerals. Data that we get from the lab can then be compared to the data collected from Mars. The minerals hematite, siderite, San Carlos olivine, magnetite and nontronite were chosen as our Mars analog minerals. 20 mg of analog Mars minerals with 5µl of 50% H2O2, and were either run immediately or placed in a sealed tube for 2, 4, or 9 days to look for changes over time with two reps being done at each time step to determine repeatability. Each sample was heated from -60 degC to 500 degC at 20 degC/min and the evolved gases were monitored with a mass spectrometer. Each sample was also analyzed with an X-ray diffraction instrument to look for changes in mineralogy. Preliminary results show three potential outcomes: 1) peroxide has no effect on the sample (e.g., hematite), 2) the mineral is unaffected but catalyzes peroxide decomposition (magnetite, siderite), or 3) peroxide alters the mineral (pyrrhotite, San Carlos olivine).

  19. Effects of Martian Surface Materials on the Thermal Decomposition of Hydrogen Peroxide

    NASA Astrophysics Data System (ADS)

    Dame, Rudger H.; Archer, Paul Douglas; Hogancamp, Joanna C.

    2017-10-01

    While hydrogen peroxide (H2O2) has been detected in the martian atmosphere, it has not been detected in surface materials. Since the Viking lander mission, we have sent instruments to Mars with the capability to detect H2O2. The Sample Analysis at Mars (SAM) instrument onboard the Curiosity Rover and Thermal and Evolved Gas Analyzer (TEGA) instrument on the Phoenix lander both detected water and oxygen releases from analyzed sediments but whether or not peroxide could be the source of these gases has not been investigated. We are investigating the possible presence of H2O2 in martian materials by analyzing Mars-relevant minerals that have been mixed with hydrogen peroxide using lab instruments configured as analogs to Mars mission instruments.The object of this research is to use lab instruments to find the effects of Mars analog minerals on hydrogen peroxide gas release temperatures, specifically gas releases of water and oxygen and also determine the effect of the peroxide on the minerals. Data that we get from the lab can then be compared to the data collected from Mars.The minerals hematite, siderite, San Carlos olivine, magnetite and nontronite were chosen as our Mars analog minerals. ~20 mg of analog Mars minerals with 5µl of 50% H2O2, and were either run immediately or placed in a sealed tube for 2, 4, or 9 days to look for changes over time with two reps being done at each time step to determine repeatability. Each sample was heated from -60 °C to 500 °C at 20 °C/min and the evolved gases were monitored with a mass spectrometer. Each sample was also analyzed with an X-ray diffraction instrument to look for changes in mineralogy.Preliminary results show three potential outcomes: 1) peroxide has no effect on the sample (e.g., hematite), 2) the mineral is unaffected but catalyzes peroxide decomposition (magnetite, siderite), or 3) peroxide alters the mineral (pyrrhotite, San Carlos olivine).

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

    ERIC Educational Resources Information Center

    Bedenbaugh, John H.; And Others

    1988-01-01

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

  1. Frost-weathering on Mars - Experimental evidence for peroxide formation

    NASA Technical Reports Server (NTRS)

    Huguenin, R. L.; Miller, K. J.; Harwood, W. S.

    1979-01-01

    The weathering of silicates by frost is investigated in relation to the formation of surface peroxides to which Viking biology experiment results have been attributed. Samples of the minerals olivine and pyroxene were exposed to water vapor at -11 to -22 C and resultant gas evolution and pH were monitored. Experiments reveal the formation of an acidic oxidant upon interaction of the mineral and H2O frost at subfreezing temperatures, which chemical indicators have suggested to be chemisorbed hydrogen peroxide. A model for the formation of chemisorbed peroxide based on the chemical reduction of the mineral by surface frost is proposed, and it is predicted that the perioxide would decay at high temperatures to H2O and adsorbed O, consistent with the long-term storage and sterilization behavior of the soil oxidants observed in the Viking Gas Exchange and Labeled Release experiments.

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

    PubMed Central

    2011-01-01

    Background Pretreatment is a critical step in the conversion of lignocellulose to fermentable sugars. Although many pretreatment processes are currently under investigation, none of them are entirely satisfactory in regard to effectiveness, cost, or environmental impact. The use of hydrogen peroxide at pH 11.5 (alkaline hydrogen peroxide (AHP)) was shown by Gould and coworkers to be an effective pretreatment of grass stovers and other plant materials in the context of animal nutrition and ethanol production. Our earlier experiments indicated that AHP performed well when compared against two other alkaline pretreatments. Here, we explored several key parameters to test the potential of AHP for further improvement relevant to lignocellulosic ethanol production. Results The effects of biomass loading, hydrogen peroxide loading, residence time, and pH control were tested in combination with subsequent digestion with a commercial enzyme preparation, optimized mixtures of four commercial enzymes, or optimized synthetic mixtures of pure enzymes. AHP pretreatment was performed at room temperature (23°C) and atmospheric pressure, and after AHP pretreatment the biomass was neutralized with HCl but not washed before enzyme digestion. Standard enzyme digestion conditions were 0.2% glucan loading, 15 mg protein/g glucan, and 48 h digestion at 50°C. Higher pretreatment biomass loadings (10% to 20%) gave higher monomeric glucose (Glc) and xylose (Xyl) yields than the 2% loading used in earlier studies. An H2O2 loading of 0.25 g/g biomass was almost as effective as 0.5 g/g, but 0.125 g/g was significantly less effective. Optimized mixtures of four commercial enzymes substantially increased post-AHP-pretreatment enzymatic hydrolysis yields at all H2O2 concentrations compared to any single commercial enzyme. At a pretreatment biomass loading of 10% and an H2O2 loading of 0.5 g/g biomass, an optimized commercial mixture at total protein loadings of 8 or 15 mg/g glucan gave

  3. Effect of species, life stage, and water temperature on the toxicity of hydrogen peroxide to fish

    USGS Publications Warehouse

    Rach, J.J.; Schreier, Theresa M.; Howe, G.E.; Redman, S.D.

    1997-01-01

    Hydrogen peroxide is a drug of low regulatory priority status that is effective in treating fish and fish eggs infected by fungi. However, only limited information is available to guide fish culturists in administering hydrogen peroxide to diseased fish. Laboratory tests were conducted to determine (1) the sensitivity of brown trout Salmo trutta, lake trout Salvelinus namaycush, fathead minnow Pimephales promelas, walleye Stizostedion vitreum, channel catfish Ictalurus punctatus, and bluegill Lepomis, machrochirus to hydrogen peroxide treatments; (2) the sensitivity of various life stages of rainbow trout Oncorhynchus mykiss to hydrogen peroxide treatments; and (3) the effect of water temperature on the acute toxicity of hydrogen peroxide to three fish species. Fish were exposed to hydrogen peroxide concentrations ranging from 100 to 5,000 mu L/L (ppm) for 15-min or 45-min treatments every other day for four consecutive treatments to determine the sensitivity of various species and life stages of fish. Except for walleye, most species of fish tested (less than or equal to 2 g) tolerated hydrogen peroxide of 1,000 mu L/L or greater. Walleyes were sensitive to hydrogen peroxide concentrations as low as 100 mu L/L. A correlation was found between the toxicity of hydrogen peroxide and the life stages of rainbow trout; larger fish were more sensitive. Generally, the toxicity of hydrogen peroxide increased for all species as water temperature increased. The results of these experiments demonstrate that it is important to consider the effects of species, life stage, and water temperature when conducting hydrogen peroxide treatments.

  4. Lipid Peroxidation: Production, Metabolism, and Signaling Mechanisms of Malondialdehyde and 4-Hydroxy-2-Nonenal

    PubMed Central

    Muñoz, Mario F.; Argüelles, Sandro

    2014-01-01

    Lipid peroxidation can be described generally as a process under which oxidants such as free radicals attack lipids containing carbon-carbon double bond(s), especially polyunsaturated fatty acids (PUFAs). Over the last four decades, an extensive body of literature regarding lipid peroxidation has shown its important role in cell biology and human health. Since the early 1970s, the total published research articles on the topic of lipid peroxidation was 98 (1970–1974) and has been increasing at almost 135-fold, by up to 13165 in last 4 years (2010–2013). New discoveries about the involvement in cellular physiology and pathology, as well as the control of lipid peroxidation, continue to emerge every day. Given the enormity of this field, this review focuses on biochemical concepts of lipid peroxidation, production, metabolism, and signaling mechanisms of two main omega-6 fatty acids lipid peroxidation products: malondialdehyde (MDA) and, in particular, 4-hydroxy-2-nonenal (4-HNE), summarizing not only its physiological and protective function as signaling molecule stimulating gene expression and cell survival, but also its cytotoxic role inhibiting gene expression and promoting cell death. Finally, overviews of in vivo mammalian model systems used to study the lipid peroxidation process, and common pathological processes linked to MDA and 4-HNE are shown. PMID:24999379

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Čeřovský, M., E-mail: scholtz@aldebaran.cz; Khun, J.; Rusová, K.

    2013-09-15

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

  6. Hydrogen peroxide stimulates cell motile activity through LPA receptor-3 in liver epithelial WB-F344 cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shibata, Ayano; Tanabe, Eriko; Inoue, Serina

    2013-04-12

    Highlights: •Hydrogen peroxide stimulates cell motility of WB-F344 cells. •LPA{sub 3} is induced by hydrogen peroxide in WB-F344 cells. •Cell motility by hydrogen peroxide is inhibited in LPA{sub 3} knockdown cells. •LPA signaling is involved in cell migration by hydrogen peroxide. -- Abstract: Hydrogen peroxide which is one of reactive oxygen species (ROS) mediates a variety of biological responses, including cell proliferation and migration. In the present study, we investigated whether lysophosphatidic acid (LPA) signaling is involved in cell motile activity stimulated by hydrogen peroxide. The rat liver epithelial WB-F344 cells were treated with hydrogen peroxide at 0.1 or 1more » μM for 48 h. In cell motility assays, hydrogen peroxide treated cells showed significantly high cell motile activity, compared with untreated cells. To measure the expression levels of LPA receptor genes, quantitative real time RT-PCR analysis was performed. The expressions of LPA receptor-3 (Lpar3) in hydrogen peroxide treated cells were significantly higher than those in control cells, but not Lpar1 and Lpar2 genes. Next, to assess the effect of LPA{sub 3} on cell motile activity, the Lpar3 knockdown cells from WB-F344 cells were also treated with hydrogen peroxide. The cell motile activity of the knockdown cells was not stimulated by hydrogen peroxide. Moreover, in liver cancer cells, hydrogen peroxide significantly activated cell motility of Lpar3-expressing cells, but not Lpar3-unexpressing cells. These results suggest that LPA signaling via LPA{sub 3} may be mainly involved in cell motile activity of WB-F344 cells stimulated by hydrogen peroxide.« less

  7. Impacts of heterogeneous reactions to atmospheric peroxides: Observations and budget analysis study

    NASA Astrophysics Data System (ADS)

    Qin, Mengru; Chen, Zhongming; Shen, Hengqing; Li, Huan; Wu, Huihui; Wang, Yin

    2018-06-01

    Atmospheric peroxides play important roles in atmospheric chemistry, acting as reactive oxidants and reservoirs of HOX and ROX radicals. Field measurements of atmospheric peroxides were conducted over urban Beijing from 2015 to 2016, including dust storm days, haze days and different seasons. We employed a box model based on RACM2 mechanism to conduct concentration simulation and budget analysis of hydrogen peroxide (H2O2) and peroxyacetic acid (PAA). In this study, heterogeneous reaction is found to be a significant sink for atmospheric H2O2 and PAA in urban Beijing. Here, we recommend a suitable uptake coefficient formula considering the water effect for model research of peroxides. It is found that H2O2 and PAA unexpectedly maintained considerable concentrations on haze days, even higher than that on non-haze days. This phenomenon is mainly ascribed to relatively high levels of volatile organic compounds and ozone on haze days. In addition, high levels of water vapor in pollution episode can promote not only the heterogeneous uptake to aerosol phase but also the production of H2O2. Atmospheric PAA formation is suggested to be sensitive to alkenes and NOX in urban Beijing. In particular, with the help of peroxides, sulfate formation rate from heterogeneous uptake could increase by ∼4 times on haze days, indicating the potential effect of peroxides on enhancement of aerosol oxidative property and secondary sulfate formation.

  8. Arsenic oxidation by UV radiation combined with hydrogen peroxide.

    PubMed

    Sorlini, S; Gialdini, F; Stefan, M

    2010-01-01

    Arsenic is a widespread contaminant in the environment around the world. The most abundant species of arsenic in groundwater are arsenite [As(III)] and arsenate [As(V)]. Several arsenic removal processes can reach good removal yields only if arsenic is present as As(V). For this reason it is often necessary to proceed with a preliminary oxidation of As(III) to As(V) prior to the removal technology. Several studies have focused on arsenic oxidation with conventional reagents and advanced oxidation processes. In the present study the arsenic oxidation was evaluated using hydrogen peroxide, UV radiation and their combination in distilled and in real groundwater samples. Hydrogen peroxide and UV radiation alone are not effective at the arsenic oxidation. Good arsenic oxidation yields can be reached in presence of hydrogen peroxide combined with a high UV radiation dose (2,000 mJ/cm(2)). The quantum efficiencies for As(III) oxidation were calculated for both the UV photolysis and the UV/H(2)O(2) processes.

  9. Progress in the development of peroxide-based anti-parasitic agents.

    PubMed

    Muraleedharan, K M; Avery, Mitchell A

    2009-08-01

    Progress made in the past decade pertaining to the development of anti-parasitic agents based on artemisinin is presented. Apart from discussions on important derivatives obtained through functionalization at the C-3, C-9, C-10 and O-11 positions of artemisinin, an outline on its seco analogs and artemisinin bundles are given for a broader perspective on structure-activity relationships. Success with synthetic peroxides, drug-hybrid approaches, broad-spectrum anti-infective properties of peroxide compounds and a survey on peroxide-containing natural products other than artemisinin with available biological data are included to highlight recent trends and avenues for future research. A supplementary material with details on the biological properties of a larger collection of molecules belonging to the above structural classes is also given for reference.

  10. Novel aqueous dual-channel aluminum-hydrogen peroxide battery

    NASA Astrophysics Data System (ADS)

    Marsh, Catherine; Licht, Stuart

    1994-06-01

    A dual-channel aluminum hydrogen peroxide battery is introduced with an open-circuit voltage of 1.9 volts, polarization losses of 0.9 mV cm(exp 2) mA(exp -1), and power densities of 1 W/cm(exp 2). Catholyte and anolyte cell compartments are separated by an Ir/Pd modified porous nickel cathode. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode. The battery is expressed by aluminum oxidation and aqueous solution phase hydrogen peroxide reduction for an overall battery discharge consisting of 2Al + 3H2O2 + 2OH(-) yields 2AlO2(-) + 4H2O E = 2.3 V. The search for electrical propulsion sources which fit the requirements for electrically powered vehicles has blurred the standard characteristics associated with electrochemical storage systems. Presently, electrochemical systems comprised of mechanically rechargeable primary batteries, secondary batteries, and fuel cells are candidates for electrochemical propulsion sources. While important advances in energy and power density continue for nonaqueous and molten electrolytes, aqueous electrolyte batteries often have an advantage in simplicity, conductivity, cost effectiveness, and environmental impact. Systems coupling aluminum anodes and aqueous electrolytes have been investigated. These systems include: aluminum/silver oxide, aluminum/manganese dioxide, aluminum air, aluminum/hydrogen peroxide aqueous batteries, and the recently introduced aluminum/ferricyanide and aluminum sulfur aqueous batteries. Conventional aqueous systems such as the nickel cadmium and lead-acid batteries are characterized by their relatively low energy densities and adverse environmental impact. Other systems have substantially higher theoretical energy capacities. While aluminum-silver oxide has demonstrated the highest steady-state power density, its high cost is an impediment for widespread utilization for electric propulsion.

  11. Hydrogen peroxide modified sodium titanates with improved sorption capabilities

    DOEpatents

    Nyman, May D [Albuquerque, NM; Hobbs, David T [North Augusta, SC

    2009-02-24

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

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

    PubMed

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

    2014-01-24

    We have synthesized ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate (2) by the reaction of 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carbonyl chloride (1), ammonium thiocyanate and ethyl 3-aminobut-2-enoate and then characterized by elemental analyses, IR, Raman, (1)H NMR, (13)C NMR and X-ray diffraction methods. The experimental and theoretical vibrational spectra of 2 were investigated. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles) were calculated using Ab Initio Hartree Fock (HF), Density Functional Theory (B3LYP) methods with 6-311++G(d,p) basis set by Gaussian 09W program. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies were calculated. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Hydrogen peroxide and caustic soda: Dancing with a dragon while bleaching

    Treesearch

    Peter W. Hart; Carl Houtman; Kolby Hirth

    2013-01-01

    When hydrogen peroxide is mixed with caustic soda, an auto-accelerating reaction can lead to generation of significant amounts of heat and oxygen. On the basis of experiments using typical pulp mill process concentration and temperatures, a relatively simple kinetic model has been developed. Evaluation of these model results reveals that hydrogen peroxide-caustic soda...

  14. Artificial photosynthesis for production of hydrogen peroxide and its fuel cells.

    PubMed

    Fukuzumi, Shunichi

    2016-05-01

    The reducing power released from photosystem I (PSI) via ferredoxin enables the reduction of NADP(+) to NADPH, which is essential in the Calvin-Benson cycle to make sugars in photosynthesis. Alternatively, PSI can reduce O2 to produce hydrogen peroxide as a fuel. This article describes the artificial version of the photocatalytic production of hydrogen peroxide from water and O2 using solar energy. Hydrogen peroxide is used as a fuel in hydrogen peroxide fuel cells to make electricity. The combination of the photocatalytic H2O2 production from water and O2 using solar energy with one-compartment H2O2 fuel cells provides on-site production and usage of H2O2 as a more useful and promising solar fuel than hydrogen. This article is part of a Special Issue entitled Biodesign for Bioenergetics--The design and engineering of electronc transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Lung tumor induction in strain A mice with benzotrichloride.

    PubMed

    Stoner, G D; You, M; Morgan, M A; Superczynski, M J

    1986-11-01

    Benzotrichloride (BTC) is used in the synthesis of benzoyl chloride and benzoyl peroxide. Epidemiological data suggest that BTC is a human lung carcinogen. In the present study, BTC was evaluated for its ability to induce lung adenomas in strain A/J mice. Four groups of 15 male and 15 female A/J mice were injected i.p. with either tricaprylin or BTC in tricaprylin three times a week for 8 weeks. BTC groups received doses totaling 1440 mg/kg, 719 mg/kg or 287 mg/kg. The mean number of lung tumors per mouse was 127 87 +/- 5.81, 43 +/- 2.44, and 17.73 +/- 1.09 in the groups treated with either 1440 mg/kg, 719 mg/kg, or 287 mg/kg, respectively. Tricaprylin-vehicle controls had a mean number of 0.46 +/- 0.15 lung tumors per mouse. Therefore, BTC produced a significant (P less than 0.001) and dose-related increase in the lung tumor response when compared to tricaprylin controls and is a potent carcinogen in the strain A mouse lung tumor bioassay.

  16. Performance of a peroxide-based cetane improvement additive in different diesel fuels

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nandi, M.K.; Jacobs, D.C.; Liotta, F.J. Jr.

    The implementation of stringent diesel engine emissions regulations is growing worldwide. The use of high cetane diesel fuels is a cost-effective option that can be used to reduce engine emissions. A direct comparison of heavy-duty diesel engine emissions for three different low sulfur diesel fuels treated with di-t-butyl peroxide and 2-ethylhexyl nitrate, at the same cetane level, was evaluated. Both the peroxide and the nitrate cetane improvement additive significantly reduced all regulated and unregulated emissions including the oxides of nitrogen (NOx) emission. Di-t-butyl peroxide shows a small advantage over ethylhexyl nitrate in reducing NOx in all the three fuels. Compatibilitymore » of the peroxide and the nitrate additives, when mixed in a fuel blend, has been demonstrated by cetane response and engine emissions for the fuel blend. 13 refs., 2 figs., 9 tabs.« less

  17. Myoglobin microplate assay to evaluate prevention of protein peroxidation.

    PubMed

    Marques, Sara S; Magalhães, Luís M; Mota, Ana I P; Soares, Tânia R P; Korsak, Barbara; Reis, Salette; Segundo, Marcela A

    2015-10-10

    The current therapeutic strategies are based on the design of multifunctional drug candidates able to interact with various disease related targets. Drugs that have the ability to scavenge reactive oxygen species (ROS), beyond their main therapeutic action, may prevent the oxidative damage of biomolecules. Therefore, analytical approaches that monitor in a continuous mode the ability of drugs to counteract peroxidation of physiologically relevant biotargets are required. In the present work, a microplate spectrophotometric assay is proposed to evaluate the ability of selected cardiovascular drugs, including angiotensin-converting enzyme (ACE) inhibitors, β -blockers and statins to prevent protein peroxidation. Myoglobin, which is a heme protein, and peroxyl radicals generated from thermolysis of 2,2'-azo-bis(2-amidinopropane) dihydrochloride at 37 °C, pH 7.4 were selected as protein model and oxidative species, respectively. Myoglobin peroxidation was continuously monitored by the absorbance decrease at 409 nm and the ability of drugs to counteract protein oxidation was determined by the calculation of the area under the curve upon the myoglobin oxidation. Fluvastatin (AUC₅₀=12.5 ± 1.2 μM) and enalapril (AUC₅₀=15.2 ± 1.8 μM) showed high ability to prevent myoglobin peroxidation, providing even better efficiency than endogenous antioxidants such as reduced glutathione. Moreover, labetalol, enalapril and fluvastatin prevent the autoxidation of myoglobin, while glutathione showed a pro-oxidant effect. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Silver-palladium catalysts for the direct synthesis of hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Khan, Zainab; Dummer, Nicholas F.; Edwards, Jennifer K.

    2017-11-01

    A series of bimetallic silver-palladium catalysts supported on titania were prepared by wet impregnation and assessed for the direct synthesis of hydrogen peroxide, and its subsequent side reactions. The addition of silver to a palladium catalyst was found to significantly decrease hydrogen peroxide productivity and hydrogenation, but crucially increase the rate of decomposition. The decomposition product, which is predominantly hydroxyl radicals, can be used to decrease bacterial colonies. The interaction between silver and palladium was characterized using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The results of the TPR and XPS indicated the formation of a silver-palladium alloy. The optimal 1% Ag-4% Pd/TiO2 bimetallic catalyst was able to produce approximately 200 ppm of H2O2 in 30 min. The findings demonstrate that AgPd/TiO2 catalysts are active for the synthesis of hydrogen peroxide and its subsequent decomposition to reactive oxygen species. The catalysts are promising for use in wastewater treatment as they combine the disinfectant properties of silver, hydrogen peroxide production and subsequent decomposition. This article is part of a discussion meeting issue 'Providing sustainable catalytic solutions for a rapidly changing world'.

  19. Hydrogen peroxide and methylhydroperoxide variations in Houston urban air during May 2009

    NASA Astrophysics Data System (ADS)

    Golovko, J.; Rappenglueck, B.; Jobson, B. T.

    2010-12-01

    Formation and destruction of peroxides along with OH and ozone cycles plays a significant role in the oxidizing capacity of the troposphere. Measurements of hydrogen peroxide and methylhydroperoxide (MHP) were carried out as a part of the Study of Houston Atmospheric Radical Precursors (SHARP) campaign during late spring 2009. The purpose of this study was to investigate peroxides variations in Houston urban atmosphere and factors controlling their distribution. Diurnal variation of hydrogen peroxide show typical pattern with the broad maximum in the afternoon for the whole period of time, with an exception on May 19th when the second maximum was determined after the sunrise. Less abundant in the atmosphere and possibly originating from different sources methylhydroperoxide demonstrated similar diurnal pattern of elevated mixing ratios in the afternoon. Elevated values of hydrogen peroxide in Houston area are associated with warm, moderately humid air, while southerly winds from the Gulf of Mexico result in H2O2 mixing ratio decrease. Some selected VOCs were analyzed in order to evaluate possible sources for both peroxides. Meteorological conditions significantly control H2O2 mixing ratios, showing elevated values primarily related to easterly and to a lesser extent to southeasterly winds. Similar pattern with the significant role of the easterly winds was observed for VOCs and was more pronounced during nighttime, pointing into industrial sector (Houston Ship Channel) influence. Increased values of H2O2/MHP ratio are mostly associated with drier northerly and northeasterly air masses, pointing out different solubility and origin of H2O2 and MHP.

  20. Electrosynthesis of hydrogen peroxide via the reduction of oxygen assisted by power ultrasound.

    PubMed

    González-García, José; Banks, Craig E; Sljukić, Biljana; Compton, Richard G

    2007-04-01

    The electrosynthesis of hydrogen peroxide using the oxygen reduction reaction has been studied in the absence and presence of power ultrasound in a non-optimized sono-electrochemical flow reactor (20 cm cathodic compartment length with 6.5 cm inner diameter) with reticulated vitreous glassy carbon electrode (30 x 40 x 10 mm, 10 ppi, 7 cm(2)cm(-3)) as the cathode. The effect of several electrochemical operational variables (pH, volumetric flow, potential) and of the sono-electrochemical parameters (ultrasound amplitude and horn-to-electrode distance) on the cumulative concentration of hydrogen peroxide and current efficiency of the electrosynthesis process have been explored. The application of power ultrasound was found to increase both the cumulative concentration of hydrogen peroxide and the current efficiency. The application of ultrasound is therefore a promising approach to the increased efficiency of production of hydrogen peroxide by electrosynthesis, even in the solutions of lower pH (<12). The results demonstrate the feasibility of at-site-of-use green synthesis of hydrogen peroxide.

  1. Lycopene control of benzophenone-sensitized lipid peroxidation

    NASA Astrophysics Data System (ADS)

    Cvetković, Dragan; Marković, Dejan

    2012-05-01

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

  2. Agent neutralization study IV. VX-caustic peroxide reactions. Final report, August 1993-February 1994

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hovanec, J.W.; Albizo, J.M.; Henderson, V.D.

    1994-08-01

    The use of concentrated mixtures of hydrogen peroxide and sodium hydroxide for the chemical neutralization (detoxification) of VX has been examined. The reaction of VX in 4 N sodium hydroxide/11% hydrogen peroxide is rapid and exothermic. Care must be taken to avoid temperature increases which can induce peroxide decomposition. This can be done by controlling the addition of VX to the reaction. (Author).

  3. Influence of calcium on glucose biosensor response and on hydrogen peroxide detection.

    PubMed

    Labat-Allietta, N; Thévenot, D R

    1998-01-01

    Of small species capable of reaching a platinum working electrode from biological samples, calcium cations have been found to inhibit significantly glucose biosensor responses. The sensitivities to glucose of sensors immersed in carbonate buffer saline solutions decreased when 0.5 mM calcium chloride was added. The degree of inhibition was proportional to the glucose response in the absence of calcium (0-17% of the normalized current). Likewise, sensor sensitivities to hydrogen peroxide decreased, in the 5-90% range, in the presence of 0.5 mM calcium. Bare Pt-lr wires show a reversible inhibition of hydrogen peroxide sensitivity. This reversible inhibition is directly related to the decrease of hydrogen peroxide oxidation rate at the platinum anode: this has been evidenced, using rotating disk electrodes, by plotting Koutecky-Levich plots. Such inhibition has been found both for free and chelated calcium cations at levels below 1 mM. Several hypotheses for possible reactions between platinum, hydrogen peroxide and calcium are discussed.

  4. Development of vapor phase hydrogen peroxide sterilization process for spacecraft applications

    NASA Technical Reports Server (NTRS)

    Rohatgi, N.; Schubert, W.; Knight, J.; Quigley, M.; Forsberg, G.; Ganapathi, G.; Yarbrough, C.; Koukol, R.

    2001-01-01

    This paper will present test data and discussion on the work we are conducting at JPL to address the following issues: 1) efficacy of sterilization process; 2) diffusion of hydrogen peroxide under sterilization process conditions into hard to reach places; 3) materials and components compatibility with the sterilization process and 4) development of methodology to protect sensitive components from hydrogen peroxide vapor.

  5. Fluorescent Probes Used for Detection of Hydrogen Peroxide under Biological Conditions.

    PubMed

    Żamojć, Krzysztof; Zdrowowicz, Magdalena; Jacewicz, Dagmara; Wyrzykowski, Dariusz; Chmurzyński, Lech

    2016-05-03

    Hydrogen peroxide is a well-established precursor of reactive oxygen and nitrogen species that are known to contribute to oxidative stress-the crucial factor responsible for the course of a wide range of phy-sicochemical processes as well as the genesis of various diseases, such as cancer and neurodegenerative disorders. Thus, the development of sensitive and selective methods for the detection and quantitative determination of hydrogen peroxide is of great importance in monitoring the in vivo production of that species and elucidating its biological functions. This review highlights the progress that has been made in the development of fluorescent and luminescent probes (excluding nanoparticles) employed to monitor hydrogen peroxide under biological conditions. Attention was focused on probes developed in the past 10 years.

  6. Developing Planetary Protection Technology: Recurrence of Hydrogen Peroxide Resistant Microbes from Spacecraft Assembly Facilities

    NASA Astrophysics Data System (ADS)

    Kempf, M. J.; Chen, F.; Quigley, M. S.; Pillai, S.; Kern, R.; Venkateswaran, K.

    2001-12-01

    Hydrogen peroxide vapor is currently the sterilant-of-choice for flight hardware because it is a low-heat sterilization process suitable for use with various spacecraft components. Hydrogen peroxide is a strong oxidizing agent that produces hydroxyl free radicals ( .OH) which attack essential cell components, including lipids, proteins, and DNA. Planetary protection research efforts at the Jet Propulsion Laboratory (JPL) are focused on developing cleaning and sterilization technologies for spacecraft preparation prior to launch. These efforts include research to assess the microbial diversity of spacecraft assembly areas and any extreme characteristics these microbes might possess. Previous studies have shown that some heat-tolerant Bacillus species isolated from the JPL Spacecraft Assembly Facility (SAF) are resistant to recommended hydrogen peroxide vapor sterilization exposures. A Bacillus species, which was related to a hydrogen peroxide resistant strain, was repeatedly isolated from various locations in the JPL-SAF. This species was found in both unclassified (entrance floors, ante-room, and air-lock) and classified (class 100K) (floors, cabinet tops, and air) areas. The phylogenetic affiliation of these strains was carried out using biochemical tests and 16S rDNA sequencing. The 16S rDNA analysis showed >99% sequence similarity to Bacillus pumilus. In order to understand the epidemiology of these strains, a more highly evolved gene (topoisomerase II β -subunit, gyrB) was also sequenced. Among 4 clades, one cluster, comprised of 3 strains isolated from the air-lock area, tightly aligned with the B. pumilus ATCC 7061 type strain (97%). The gyrB sequence similarity of this clade was only 91% with the 3 other clades. The genetic relatedness of these strains, as per pulse field gel electrophoresis patterns, will be presented. The vegetative cells and spores of a number of isolates were tested for their hydrogen peroxide resistance. Cells and spores were

  7. Colorimetric determination of Al(III) based on the aggregation of gold nanoparticles functionalized with novel 4-benzoyl pyrazolone derivative

    NASA Astrophysics Data System (ADS)

    Abubaker, Mariam; Ngah, Che Wan Zanariah Che Wan; Ahmad, Musa; Kuswandi, Bambang

    2018-06-01

    A sensitive and selective colorimetric method has been developed for detection of Al3+ ion using 4-benzoyl pyrazolone-functionalized gold nanoparticles (BMPBP-AuNPs) as novel colorimetric probes. The BMPBP-AuNPs were characterized by UV-visible spectrometry and transmission electron microscopy (TEM). It was found that the addition of the Al3+ ions led to a rapid aggregation of the BMPBP-AuNPs, which changed the color of the mixture from red to blue. Furthermore, there was a shift in the characteristic surface plasmon resonance (SPR) peak from 524 to 650 nm of BMPBP-AuNPs, which confirmed that a good linear relation (R2 = 0.9935) was present between the absorption ratio of 524 and 650 nm. Also, the assay detected the Al3+ ion concentrations in the linear range 0-12 ppm with the detection limit is 0.05 ppm. Finally, the synthesized BMPBP-AuNPs were successfully used as a colorimetric sensor for the selective and sensitive detection of the Al3+ ions in water samples.

  8. Discovery of novel 2-aryl-4-benzoyl-imidazoles targeting the colchicines binding site in tubulin as potential anticancer agents

    PubMed Central

    Chen, Jianjun; Wang, Zhao; Li, Chien-Ming; Lu, Yan; Vaddady, Pavan K.; Meibohm, Bernd; Dalton, James T.; Miller, Duane D.; Li, Wei

    2010-01-01

    A series of 2-aryl-4-benzoyl-imidazoles (ABI) was synthesized as a result of structural modifications based on the previous set of 2-aryl-imidazole-4-carboxylic amide (AICA) derivatives and 4-substituted methoxylbenzoyl-aryl-thiazoles (SMART). The average IC50 of the most active compound (5da) was 15.7 nM. ABI analogs have substantially improved aqueous solubility (48.9 μg/mL for 5ga vs. 0.909 μg/mL for SMART-1, 0.137 μg/mL for paclitaxel, and 1.04 μg/mL for Combretastatin A4). Mechanism of action studies indicate that the anticancer activity of ABI analogs is through inhibition of tubulin polymerization by interacting with the colchicine binding site. Unlike paclitaxel and colchicine, the ABI compounds were equally potent against multidrug resistant cancer cells and the sensitive parental melanoma cancer cells. In vivo results indicated that 5cb was more effective than DTIC in inhibiting melanoma xenograph tumor growth. Our results suggest that the novel ABI compounds may be developed to effectively treat drug-resistant tumors. PMID:20919720

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

    PubMed

    Patri, Gaurav; Acharya, Gourismita; Agrawal, Pratik; Panda, Vijeta

    2016-08-01

    Hydrogen peroxide (30%) is a commonly used "in office" bleaching agent. Deleterious effects of hydrogen peroxide on the pulp have been observed. 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). 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. The data obtained were analyzed using one way ANOVA and Student's t-test. 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. 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.

  10. Residual antibacterial activity of dog hairs after therapy with antimicrobial shampoos.

    PubMed

    Kloos, Isabell; Straubinger, Reinhard K; Werckenthin, Christiane; Mueller, Ralf S

    2013-04-01

    Topical antimicrobial treatment for canine pyoderma is becoming increasingly important, but little is known about the mechanism of action and persistence of activity of antimicrobial shampoos. To determine the residual antimicrobial activity on canine hairs treated with antimicrobial shampoos. Forty-two dogs from a research institution. Dogs were treated with six different shampoos and the combination of one shampoo and conditioner containing benzoyl peroxide, chlorhexidine in different concentrations (0.8, 2, 3 and 4%), ethyl lactate and miconazole twice weekly for 2 weeks. A shampoo vehicle without antimicrobial ingredients was used as the control. Hairs were collected immediately after and 2, 4 and 7 days after the last shampoo therapy and placed onto an agar plate streaked with Staphylococcus pseudintermedius. After incubation, the growth inhibition zone around the hair shafts was measured. The largest zone of inhibition of bacterial growth was seen after shampoos containing 2 and 3% chlorhexidine and the combination of chlorhexidine shampoo and conditioner. The zone of inhibition was smaller with the shampoos containing 0.8 and 4% chlorhexidine. There was no difference between the inhibition zones post-treatment with benzoyl peroxide, ethyl lactate and control. The efficacy of a shampoo is dependent not only on the concentration of the active ingredients but also on the shampoo formulation. Hair shafts treated with shampoos containing 2 and 3% chlorhexidine and the combination of shampoo and conditioner inhibited bacterial growth significantly and seem suitable to treat canine bacterial pyoderma. © 2013 The Authors. Veterinary Dermatology © 2013 ESVD and ACVD.

  11. Free Radicals Mediate Peroxidative Damage in Guinea Pig Hippocampus in vitro

    DTIC Science & Technology

    1989-01-01

    Peroxidative Damage in Guinea Pig Hippocampus In Vitro T.C. Pellmar, K.L. Neel, and K.H. Lee Physiology Department. Armed Forces Radiobiology Research...removed from brains of euthanized evaluate the free radical involvement in peroxidative guinea pigs . Electrical stimulation of an orthodromic damage to...Hartley guinea pigs as previously described (Pellmar, 1986, 1987). Animals were anesthetized with halothane and euthanized by cervical dislocation

  12. Hydrogen peroxide stimulates cell motile activity through LPA receptor-3 in liver epithelial WB-F344 cells.

    PubMed

    Shibata, Ayano; Tanabe, Eriko; Inoue, Serina; Kitayoshi, Misaho; Okimoto, Souta; Hirane, Miku; Araki, Mutsumi; Fukushima, Nobuyuki; Tsujiuchi, Toshifumi

    2013-04-12

    Hydrogen peroxide which is one of reactive oxygen species (ROS) mediates a variety of biological responses, including cell proliferation and migration. In the present study, we investigated whether lysophosphatidic acid (LPA) signaling is involved in cell motile activity stimulated by hydrogen peroxide. The rat liver epithelial WB-F344 cells were treated with hydrogen peroxide at 0.1 or 1 μM for 48 h. In cell motility assays, hydrogen peroxide treated cells showed significantly high cell motile activity, compared with untreated cells. To measure the expression levels of LPA receptor genes, quantitative real time RT-PCR analysis was performed. The expressions of LPA receptor-3 (Lpar3) in hydrogen peroxide treated cells were significantly higher than those in control cells, but not Lpar1 and Lpar2 genes. Next, to assess the effect of LPA3 on cell motile activity, the Lpar3 knockdown cells from WB-F344 cells were also treated with hydrogen peroxide. The cell motile activity of the knockdown cells was not stimulated by hydrogen peroxide. Moreover, in liver cancer cells, hydrogen peroxide significantly activated cell motility of Lpar3-expressing cells, but not Lpar3-unexpressing cells. These results suggest that LPA signaling via LPA3 may be mainly involved in cell motile activity of WB-F344 cells stimulated by hydrogen peroxide. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Functional analysis of a novel hydrogen peroxide resistance gene in Lactobacillus casei strain Shirota.

    PubMed

    Serata, Masaki; Kiwaki, Mayumi; Iino, Tohru

    2016-11-01

    Lactic acid bacteria have a variety of mechanisms for tolerance to oxygen and reactive oxygen species, and these mechanisms differ among species. Lactobacillus casei strain Shirota grows well under aerobic conditions, indicating that the various systems involved in oxidative stress resistance function in this strain. To elucidate the mechanism of oxidative stress resistance in L. casei strain Shirota, we examined the transcriptome response to oxygen or hydrogen peroxide exposure. We then focused on an uncharacterized gene that was found to be up-regulated by both oxygen and hydrogen peroxide stress; we named the gene hprA1 (hydrogen peroxide resistance gene). This gene is widely distributed among lactobacilli. We investigated the involvement of this gene in oxidative stress resistance, as well as the mechanism of tolerance to hydrogen peroxide. Growth of L. casei MS105, an hprA1-disrupted mutant, was not affected by oxygen stress, whereas the survival rate of MS105 after hydrogen peroxide treatment was markedly reduced compared to that of the wild-type. However, the activity of MS105 in eliminating hydrogen peroxide was similar to that of the wild-type. We cloned hprA1 from L. caseiShirota and purified recombinant HprA1 protein from Escherichia coli. We demonstrated that the recombinant HprA1 protein bound to iron and prevented the formation of a hydroxyl radical in vitro. Thus, HprA1 protein probably contributes to hydrogen peroxide tolerance in L. casei strain Shirota by binding to iron in the cells and preventing the formation of a hydroxyl radical.

  14. Engineering bacterial motility towards hydrogen-peroxide.

    PubMed

    Virgile, Chelsea; Hauk, Pricila; Wu, Hsuan-Chen; Shang, Wu; Tsao, Chen-Yu; Payne, Gregory F; Bentley, William E

    2018-01-01

    Synthetic biologists construct innovative genetic/biological systems to treat environmental, energy, and health problems. Many systems employ rewired cells for non-native product synthesis, while a few have employed the rewired cells as 'smart' devices with programmable function. Building on the latter, we developed a genetic construct to control and direct bacterial motility towards hydrogen peroxide, one of the body's immune response signaling molecules. A motivation for this work is the creation of cells that can target and autonomously treat disease, the latter signaled by hydrogen peroxide release. Bacteria naturally move towards a variety of molecular cues (e.g., nutrients) in the process of chemotaxis. In this work, we engineered bacteria to recognize and move towards hydrogen peroxide, a non-native chemoattractant and potential toxin. Our system exploits oxyRS, the native oxidative stress regulon of E. coli. We first demonstrated H2O2-mediated upregulation motility regulator, CheZ. Using transwell assays, we showed a two-fold increase in net motility towards H2O2. Then, using a 2D cell tracking system, we quantified bacterial motility descriptors including velocity, % running (of tumble/run motions), and a dynamic net directionality towards the molecular cue. In CheZ mutants, we found that increased H2O2 concentration (0-200 μM) and induction time resulted in increased running speeds, ultimately reaching the native E. coli wild-type speed of ~22 μm/s with a ~45-65% ratio of running to tumbling. Finally, using a microfluidic device with stable H2O2 gradients, we characterized responses and the potential for "programmed" directionality towards H2O2 in quiescent fluids. Overall, the synthetic biology framework and tracking analysis in this work will provide a framework for investigating controlled motility of E. coli and other 'smart' probiotics for signal-directed treatment.

  15. The first characterization of free radicals formed from cellular COX-catalyzed peroxidation.

    PubMed

    Gu, Yan; Xu, Yi; Law, Benedict; Qian, Steven Y

    2013-04-01

    Through free radical-mediated peroxidation, cyclooxygenase (COX) can metabolize dihomo-γ-linolenic acid (DGLA) and arachidonic acid (AA) to form well-known bioactive metabolites, namely, the 1-series of prostaglandins (PGs1) and the 2-series of prostaglandins (PGs2), respectively. Unlike PGs2, which are generally viewed as proinflammatory and procarcinogenic PGs, PGs1 may possess anti-inflammatory and anti-cancer activity. Previous studies using ovine COX along with spin trapping and the LC/ESR/MS technique have shown that certain exclusive free radicals are generated from different free radical reactions in DGLA and AA peroxidation. However, it has been unclear whether the differences were associated with the contrasting bioactivity of DGLA vs AA. The aim of this study was to refine the LC/MS and spin trapping technique to make it possible for the association between free radicals and cancer cell growth to be directly tested. Using a colon cancer cell line, HCA-7 colony 29, and LC/MS along with a solid-phase extraction, we were able to characterize the reduced forms of radical adducts (hydroxylamines) as the free radicals generated from cellular COX-catalyzed peroxidation. For the first time, free radicals formed in the COX-catalyzed peroxidation of AA vs DGLA and their association with cancer cell growth were assessed (cell proliferation via MTS and cell cycle distribution via propidium iodide staining) in the same experimental setting. The exclusive free radicals formed from the COX-catalyzed peroxidation of AA and DGLA were shown to be correlated with the cell growth response. Our results indicate that free radicals generated from the distinct radical reactions in COX-catalyzed peroxidation may represent the novel metabolites of AA and DGLA that correspond to their contrasting bioactivity. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. The First Characterization of Free Radicals Formed From Cellular COX-Catalyzed Peroxidation

    PubMed Central

    Gu, Yan; Xu, Yi; Law, Benedict; Qian, Steven Y.

    2014-01-01

    Through free radical-mediated peroxidation, cyclooxygenase (COX) can metabolize dihomo-γ-linolenic acid (DGLA) and arachidonic acid(AA) to form well-known bioactive metabolites, namely, the 1-series of prostaglandins (PGs1) and 2-series of prostaglandins(PGs2), respectively. Unlike PGs2, which are generally viewed as pro-inflammatory and pro-carcinogenic PGs, PGs1 may possess anti-inflammatory and anti-cancer activity. Previous studies using ovine COX along with spin trapping and the LC/ESR/MS technique have shown that certain exclusive free radicals are generated from different free radical reactions in DGLA and AA peroxidation. However, it has been unclear whether the differences were associated with the contrasting bioactivity of DGLA vs. AA. The aim of this study was to refine the LC/MS and spin-trapping technique to make it possible for the association between free radicals and cancer cell growth to be directly tested. Using a colon cancer cell line, HCA-7 colony 29, and LC/MS along with a solid phase extraction, we were able to characterize the reduced forms of radical adducts (hydroxylamines) as the free radicals generated from cellular COX-catalyzed peroxidation. For the first time, free radicals formed in the COX-catalyzed peroxidation of AA vs. DGLA and their association with cancer cell growth was assessed (cell proliferation via MTS and cell cycle distribution via PI staining) in the same experimental setting. The exclusive free radicals formed from the COX-catalyzed peroxidation of AA and DGLA were shown to be correlated with the cell growth response. Our results indicate that free radicals generated from the distinct radical reactions in COX-catalyzed peroxidation may represent the novel metabolites of AA and DGLA that correspond to their contrasting bioactivity. PMID:23261941

  17. Preparation and characterization of (St-DVB-MAA) ion exchange resins

    NASA Astrophysics Data System (ADS)

    Jiang, Shanquan; Sun, Xiangwei; Ling, Lixing; Wang, Shumin; Wu, Wufeng; Cheng, Shihong; Hu, Yue; Zhong, Chunyan

    2017-08-01

    In this paper, used polyvinyl alcohol as dispersing agent, Benzoyl peroxide as initiator of polymerization, Divinyl benzene as cross-linking agent, Styrene and 2-Methylpropenoic acid as monomer, ion exchange resin (copolymer of St-DVB-MAA)were prepared by suspension polymerization on 80°C. The structures, components and properties of the prepared composite micro gels were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA). The experiment of ion exchange was conducted by resin to deal with copper ions in the solution. The result showed that performance of the ion exchange capacity was excellent, which impacted by pH.

  18. Reactive oxygen species and lipid peroxidation product-scavenging ability of yogurt organisms.

    PubMed

    Lin, M Y; Yen, C L

    1999-08-01

    The antioxidative activity of the intracellular extracts of yogurt organisms was investigated. All 11 strains tested, including five strains of Streptococcus thermophilus and six strains of Lactobacillus delbrueckii ssp. bulgaricus, demonstrated an antioxidative effect on the inhibition of linoleic acid peroxidation. The antioxidative effect of intracellular extracts of 10(8) cells of yogurt organisms was equivalent to 25 to 96 ppm butylated hydroxytoluene, which indicated that all strains demonstrated excellent antioxidative activity. The scavenging of reactive oxygen species, hydroxyl radical, and hydrogen peroxide was studied for intracellular extracts of yogurt organisms. All strains showed reactive oxygen species-scavenging ability. Lactobacillus delbrueckii ssp. bulgaricus Lb demonstrated the highest hydroxyl radical-scavenging ability at 234 microM. Streptococcus thermophilus MC and 821 and L. delbrueckii ssp. bulgaricus 448 and 449 scavenged the most hydrogen peroxide at approximately 50 microM. The scavenging ability of lipid peroxidation products, t-butylhydroperoxide and malondialdehyde, was also evaluated. Results showed that the extracts were not able to scavenge the t-butylhydroperoxide. Nevertheless, malondialdehyde was scavenged well by most strains.

  19. Hydrogen peroxide bleaching of cotton in ultrasonic energy.

    PubMed

    Mistik, S Ilker; Yükseloglu, S Müge

    2005-12-01

    It is well known that, conventional hydrogen peroxide bleaching process is an important and a specific step for wet processors; however it has some problems such as long time, high energy consumption. On the other hand, using ultrasonic energy in bleaching is an alternative method for the conventional processes. In this work, 100% cotton materials of different forms such as raw fibre, ring-spun yarns and knitted fabrics produced from these cottons, were treated with hydrogen peroxide in two different concentrations (5 mL/L and 10 mL/L), at three different temperatures (20 degrees C, 30 degrees C, 40 degrees C) and times (20 min, 30 min, 60 min). Whiteness Index of the samples were then measured spectrophotometrically and the overall results were compared.

  20. Determination of berberine in pharmaceutical preparations using acidic hydrogen peroxide-nitrite chemiluminescence system.

    PubMed

    Liang, Yao-Dong; Yu, Chun-Xia

    2013-03-01

    A stronger chemiluminescence (CL) was observed when hydrogen peroxide was mixed with nitrite and berberine in sulfuric acid solution. The stronger CL originated from peroxidation of berberine by peroxynitrous acid that was synthesized online by the mixing of acidic hydrogen peroxide solution with nitrite solution in a flow system. The emitting species was excited state oxyberberine, a peroxidized product of berberine. Based on the stronger CL, a flow injection CL method for the determination of berberine was proposed. Under optimum experimental conditions, the stronger CL intensity was linearly related to the concentration of berberine over the range of 2.0 × 10(-7) -2.0 × 10(-5) mol L(-1) . The limit of detection (s/n = 3) was 6.2 × 10(-8) mol L(-1) . The proposed method has been evaluated by analyzing berberine in pharmaceutical preparations. Copyright © 2011 John Wiley & Sons, Ltd.

  1. The hydrogen peroxide impact on larval settlement and metamorphosis of abalone Haliotis diversicolor supertexta

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangjing; Yang, Zhihui; Cai, Zhonghua

    2008-08-01

    Abalone Haliotis diversicolor supertexta is an important economic mollusk. The settlement and metamorphosis are two critical stages during its development period, which has direct influence on abalone survival and production. The influence of reactive oxygen species (hydrogen peroxide) on abalone embryo and juvenile development were examined in this study. Larvae of Haliotis diversicolor supertexta were induced to settlement and metamorphose by exposure to seawater supplemented with hydrogen peroxide. They had the best performance at 800 μmol/L. The concentration of 1 000 μmol/L or higher was toxic to the larvae, as the larvae could settle down only at benthic diatom plates without complete metamorphosis. In addition, H2O2 adding time was critical to the larval performance. 24h after two-day post-fertilization was proved to be the optimal adding time. In this paper, two action mechanisms of hydrogen peroxide are discussed: (1) hydrogen peroxide has direct toxicity to ciliated cells, thus cause apoptosis; (2) hydrogen peroxide, as a product from catecholamines’ autoxidation process in vivo, can reverse this process to produce neuro-transmitters to induce abalone metamorphosis.

  2. Surface Passivation of CdZnTe Detector by Hydrogen Peroxide Solution Etching

    NASA Technical Reports Server (NTRS)

    Hayes, M.; Chen, H.; Chattopadhyay, K.; Burger, A.; James, R. B.

    1998-01-01

    The spectral resolution of room temperature nuclear radiation detectors such as CdZnTe is usually limited by the presence of conducting surface species that increase the surface leakage current. Studies have shown that the leakage current can be reduced by proper surface preparation. In this study, we try to optimize the performance of CdZnTe detector by etching the detector with hydrogen peroxide solution as function of concentration and etching time. The passivation effect that hydrogen peroxide introduces have been investigated by current-voltage (I-V) measurement on both parallel strips and metal-semiconductor-metal configurations. The improvements on the spectral response of Fe-55 and 241Am due to hydrogen peroxide treatment are presented and discussed.

  3. Hydrogen peroxide prevents vascular calcification induced ROS production by regulating Nrf-2 pathway.

    PubMed

    Zhang, Wensong; Li, Yi; Ding, Hanlu; Du, Yaqin; Wang, Li

    2016-08-01

    Although vascular calcification in end-stage renal disease (ESRD) represents a ubiquitous human health problem, effective therapies with limited side effects are still lacking, and the precise mechanisms are not fully understood. The Nrf-2/ARE pathway is a pivotal to regulate anti-oxidative responses in vascular calcification upon ESRD. Although Nrf-2 plays a crucial role in atherosclerosis, pulmonary fibrosis, and brain ischemia, the effect of Nrf-2 and oxidative stress on vascular calcification in ESRD patients is still unclear. The aim of this research was to study the protective role of hydrogen peroxide in vascular calcification and the mechanism of Nrf-2 and oxidative stress on vascular calcification. Here we used the rat vascular smooth muscle cell model of β-glycerophosphate-induced calcification resembling vascular calcification in ESRD to investigate the therapeutic effect of 0.01 mM hydrogen peroxide on vascular calcification and further explores the possible underlying mechanisms. Our current report shows the in vitro role of 0.01 mM hydrogen peroxide in protecting against intracellular ROS accumulation upon vascular calcification. Both hydrogen peroxide and sulforaphane pretreatment reduced ROS production, increased the expression of Nrf-2, and decreased the expression of Runx2 following calcification. Our study demonstrates that 0.01 mM hydrogen peroxide can effectively protect rat aortic vascular smooth muscle cells against oxidative stress by preventing vascular calcification induced ROS production through Nrf-2 pathway. These data might define an antioxidant role of hydrogen peroxide in vascular calcification upon ESRD.

  4. Destruction kinetic of PCDDs/Fs in MSWI fly ash using microwave peroxide oxidation.

    PubMed

    Chang, Yu-Min; Fang, Wen-Bin; Tsai, Kuo-Sheng; Kao, Jimmy C M; Lin, Kae-Long; Chen, Ching-Ho

    2015-01-01

    Microwave peroxide oxidation is a less greenhouse gas emission and energy-efficient technology to destroy toxic organic compounds in hazardous waste. The research novelty is to adopt the innovative microwave peroxide oxidation in H2SO4/HNO3 solution to efficiently destroy the polychlorinated dibenzo-p-dioxins (PCDDs)/Fs in municipal solid waste incineration fly ash. The major objective of this paper is to study dynamic destruction of PCDDs/Fs using the microwave peroxide oxidation. Almost all PCDDs/Fs in the raw fly ash can be destructed in 120 min at a temperature of 423 K using the microwave peroxide oxidation treatment. It was found that the microwave peroxide oxidation provides the potential to destruct the PCDDs/Fs content in municipal solid waste incinerator (MSWI) fly ash to a low level as a function of treatment time. A useful kinetic correlation between destruction efficiency and treatment conditions is proposed on the basis of the experimental data obtained in this study. The significance of this work in terms of practical engineering applications is that the necessary minimum treatment time can be solved using a proposed graphic illustration method, by which the minimum treatment time is obtained if the desired destruction efficiency and treatment temperature are known. Because of inorganic salt dissolution, the temperature would be a critical factor facilitating the parts of fly ash dissolution. Material loss problem caused by the microwave peroxide oxidation and the effects of treatment time and temperature are also discussed in this paper.

  5. Cobalt-Catalyzed Trifluoromethylation-Peroxidation of Unactivated Alkenes with Sodium Trifluoromethanesulfinate and Hydroperoxide.

    PubMed

    Zhang, Hong-Yu; Ge, Chao; Zhao, Jiquan; Zhang, Yuecheng

    2017-10-06

    Disclosed herein is an unprecedented cobalt-catalyzed trifluoromethylation-peroxidation of unactivated alkenes. In this process the hydroperoxide acts as a radical initiator as well as a coupling partner. The cheap and readily available sodium trifluoromethanesulfinate serves as the CF 3 source in the reaction. Various alkenes are transformed into vicinal trifluoromethyl-peroxide compounds in moderate to good yields.

  6. Effect of oil source and peroxidation status on broiler performance and oxidative stress

    USDA-ARS?s Scientific Manuscript database

    Oil source has been shown to affect broiler performance and oxidative status. Lipid peroxidation may also affect animal performance and oxidative status through the generation and degradation of peroxidation compounds which differ according to oil source and temperature and length of heating. The ob...

  7. Propulsion Ground Testing with High Test Peroxide: Lessons Learned

    NASA Technical Reports Server (NTRS)

    Bruce, Robert; Taylor, Gary; Taliancich, Paula

    2002-01-01

    Propulsion Ground Testing with High Test Peroxide (85 to 98% concentration) began at the NASA John C. Stennis Space Center in calendar year 1998, when the E3 Test Facility was modified to accomodate hydrogen peroxide (H2O2) in order to suport the research and development testing of the USAF Upper Stage Flight Experiment rocket engine. Since that time, efforts have continued to provide actual and planned test services to various customers, both U.S. Government and Commercial, in the ground test of many test articles, ranging from gas generators, to catalyst beds, to turbomachinery, to main injectors, to combustion chambers, to integrated rocket engines, to integrated stages. Along this path, and over the past 4 years, there has been both the rediscovery of previously learned lessons, through literature search, archive review, and personal interviews, as well as the learning of many new lessons as new areas are explored and new endeavors are tried. This paper will summarize those lessons learned in an effort to broaden the knowledge base as High Test Peroxide is considered more widely for use in rocket propulsion applications.

  8. Measurement of hydrogen peroxide and organic hydroperoxide concentrations during autumn in Beijing, China.

    PubMed

    Zhang, Qingyu; Liu, Jiaoyu; He, Youjiang; Yang, Jiaying; Gao, Jian; Liu, Houfeng; Tang, Wei; Chen, Yizhen; Fan, Wenhao; Chen, Xuan; Chai, Fahe; Hatakeyama, Shiro

    2018-02-01

    Gaseous peroxides play important roles in atmospheric chemistry. To understand the pathways of the formation and removal of peroxides, atmospheric peroxide concentrations and their controlling factors were measured from 7:00 to 20:00 in September, October, and November 2013 at a heavily trafficked residential site in Beijing, China, with average concentrations of hydrogen peroxide (H 2 O 2 ) and methyl hydroperoxide (MHP) at 0.55ppb and 0.063ppb, respectively. H 2 O 2 concentrations were higher in the afternoon and lower in the morning and evening, while MHP concentrations did not exhibit a regular diurnal pattern. Both H 2 O 2 and MHP concentrations increased at dusk in most cases. Both peroxides displayed monthly variations with higher concentrations in September. These results suggested that photochemical activity was the main controlling factor on variations of H 2 O 2 concentrations during the measurement period. Increasing concentrations of volatile organic compounds emitted by motor vehicles were important contributors to H 2 O 2 and MHP enrichment. High levels of H 2 O 2 and MHP concentrations which occurred during the measurement period probably resulted from the transport of a polluted air mass with high water vapor content passing over the Bohai Bay, China. Copyright © 2017. Published by Elsevier B.V.

  9. Characterization of an organic phase peroxide biosensor based on horseradish peroxidase immobilized in Eastman AQ.

    PubMed

    Konash, Anastassija; Magner, Edmond

    2006-07-15

    Due to their frequent occurrence in food, cosmetics and pharmaceutical products, and their poor solubility in water, the detection of peroxides in organic solvents has aroused significant interest. For diagnostics or on-site testing, a fast and specific experimental approach is required. Although aqueous peroxide biosensors are well known, they are usually not suitable for nonaqueous applications due to their instability. Here we describe an organic phase biosensor for hydrogen peroxide based on horseradish peroxidase immobilized in an Eastman AQ 55 polymer matrix. Rotating disc amperometry was used to examine the effect of the solvent properties, the amount and pH of added buffer, the concentration of peroxide and ferrocene dimethanol, and the amount of Eastman AQ 55 and of enzyme on the response of the biosensor to hydrogen peroxide. The response of the biosensor was limited by diffusion. Linear responses (with detection limits to hydrogen peroxide given in parentheses) were obtained in methanol (1.2 microM), ethanol (0.6 microM), 1-propanol (2.8 microM), acetone (1.4 microM), acetonitrile (2.6 microM), and ethylene glycol (13.6 microM). The rate of diffusion of ferrocene dimethanol was more constrained than the rate of diffusion of hydrogen peroxide, resulting in a comparatively narrow linear range. The main advantages of the sensor are its ease of use and a high degree of reproducibility, together with good operational and storage stability.

  10. Measurement of formic acid, acetic acid and hydroxyacetaldehyde, hydrogen peroxide, and methyl peroxide in air by chemical ionization mass spectrometry: airborne method development

    NASA Astrophysics Data System (ADS)

    Treadaway, Victoria; Heikes, Brian G.; McNeill, Ashley S.; Silwal, Indira K. C.; O'Sullivan, Daniel W.

    2018-04-01

    A chemical ionization mass spectrometry (CIMS) method utilizing a reagent gas mixture of O2, CO2, and CH3I in N2 is described and optimized for quantitative gas-phase measurements of hydrogen peroxide (H2O2), methyl peroxide (CH3OOH), formic acid (HCOOH), and the sum of acetic acid (CH3COOH) and hydroxyacetaldehyde (HOCH2CHO; also known as glycolaldehyde). The instrumentation and methodology were designed for airborne in situ field measurements. The CIMS quantification of formic acid, acetic acid, and hydroxyacetaldehyde used I- cluster formation to produce and detect the ion clusters I-(HCOOH), I-(CH3COOH), and I-(HOCH2CHO), respectively. The CIMS also produced and detected I- clusters with hydrogen peroxide and methyl peroxide, I-(H2O2) and I-(CH3OOH), though the sensitivity was lower than with the O2- (CO2) and O2- ion clusters, respectively. For that reason, while the I- peroxide clusters are presented, the focus is on the organic acids. Acetic acid and hydroxyacetaldehyde were found to yield equivalent CIMS responses. They are exact isobaric compounds and indistinguishable in the CIMS used. Consequently, their combined signal is referred to as the acetic acid equivalent sum. Within the resolution of the quadrupole used in the CIMS (1 m/z), ethanol and 1- and 2-propanol were potential isobaric interferences to the measurement of formic acid and the acetic acid equivalent sum, respectively. The CIMS response to ethanol was 3.3 % that of formic acid and the response to either 1- or 2-propanol was 1 % of the acetic acid response; therefore, the alcohols were not considered to be significant interferences to formic acid or the acetic acid equivalent sum. The multi-reagent ion system was successfully deployed during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ) in 2014. The combination of FRAPPÉ and laboratory calibrations allowed for the post-mission quantification of formic acid and the acetic acid equivalent sum observed during

  11. Isolation of Nicotinic Acid (Vitamin B3) and N-Propylamine after Myosmine Peroxidation.

    PubMed

    Zwickenpflug, Wolfgang; Högg, Christof; Feierfeil, Johannes; Dachs, Manuel; Gudermann, Thomas

    2016-01-13

    The alkaloid myosmine (3-(1-pyrroline-2-yl)pyridine) is widespread in biological matrixes including foodstuffs and tobacco products. Some in vitro tests in cellular systems showed mutagenic activity for myosmine. Myosmine activation including peroxidation mechanism employs unstable oxazirane intermediates. The formation of minor metabolite 3-hydroxymethyl-pyridine in rat metabolism experiments as well as in in vitro peroxidation assays suggests its further oxidation to nicotinic acid and possible concomitant formation of n-propylamine. A sensitive high-performance liquid chromatography-ultraviolet (HPLC-UV) method was developed for the direct analysis of n-propylamine in the peroxidation assay solution of myosmine employing derivatization with 3,5-dinitrobenzoyl chloride. Additionally, during peroxidation procedures, formation of 3-pyridylmethanol to nicotinic acid, the essential vitamin B3, was observed and characterized using HPLC-UV and gas chromatography/mass spectrometry. This new reaction pathway may present further contribution to our knowledge of myosmine's significance in human food including its activation in human organism, foodstuffs, and biological systems.

  12. Evaluation of a hydrogen peroxide-based system for high-level disinfection of vaginal ultrasound probes.

    PubMed

    Johnson, Stephen; Proctor, Matthew; Bluth, Edward; Smetherman, Dana; Baumgarten, Katherine; Troxclair, Laurie; Bienvenu, Michele

    2013-10-01

    Because of the complex process and the risk of errors associated with the glutaraldehyde-based solutions previously used at our institution for disinfection, our department has implemented a new method for high-level disinfection of vaginal ultrasound probes: the hydrogen peroxide-based Trophon system (Nanosonics, Alexandria, New South Wales, Australia). The aim of this study was to compare the time difference, safety, and sonographers' satisfaction between the glutaraldehyde-based Cidex (CIVCO Medical Solutions, Kalona, IA) and the hydrogen peroxide-based Trophon disinfection systems. The Institutional Review Board approved a 14-question survey administered to the 13 sonographers in our department. Survey questions addressed a variety of aspects of the disinfection processes with graded responses over a standardized 5-point scale. A process diagram was developed for each disinfection method with segmental timing analysis, and a cost analysis was performed. Nonvariegated analysis of the survey data with the Wilcoxon signed rank test showed a statistical difference in survey responses in favor of the hydrogen peroxide-based system over the glutaraldehyde-based system regarding efficiency (P = .0013), ease of use (P = .0013), ability to maintain work flow (P = .026), safety (P = .0026), fixing problems (P = .0158), time (P = .0011), and overall satisfaction (P = .0018). The glutaraldehyde-based system took 32 minutes versus 14 minutes for the hydrogen peroxide-based system; the hydrogen peroxide-based system saved on average 7.5 hours per week. The cost of the hydrogen peroxide-based system and weekly maintenance pays for itself if 1.5 more ultrasound examinations are performed each week. The hydrogen peroxide-based disinfection system was proven to be more efficient and viewed to be easier and safer to use than the glutaraldehyde-based system. The adoption of the hydrogen peroxide-based system led to higher satisfaction among sonographers.

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

    DOEpatents

    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.

  14. [Accelerated senescence of fresh-cut Chinese water chestnut tissues in relation to hydrogen peroxide accumulation].

    PubMed

    Peng, Li-Tao; Jiang, Yue-Ming; Yang, Shu-Zhen; Pan, Si-Yi

    2005-10-01

    Accelerated senescence of fresh-cut Chinese water chestnut (CWC) tissues in relation to active oxygen species (AOS) metabolism was investigated. Fresh-cut CWC (2 mm thick) and intact CWC were stored at 4 degrees C in trays wrapped with plastic films. Changes in superoxide anion production rate, activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were monitored, while contents of hydrogen peroxide, ascorbic acid, MDA as well as electrolyte leakage were measured. Fresh-cutting of CWC induced activities of SOD, CAT and APX to a certain extent (Fig. 2B and Fig. 3), but simultaneously stimulated superoxide anion production markedly (Fig. 2A), enhanced hydrogen peroxide accumulation and accelerated loss in ascorbic acid (Figs. 4 and 5), which resulted in increased lipid peroxidation indicated by malondialdehyde (MDA) content and electrolyte leakage (Fig. 1). Statistics analysis indicated that there was a significantly positive correlation among hydrogen peroxide accumulation, MDA content and electrolyte leakage (Table 1). Histochemical detection with 3, 3'-diaminobenzidine further demonstrated that hydrogen peroxide accumulation increased in fresh-cut CWC during storage (Fig. 5). AOS production rate and activities of SOD, CAT and APX changed little while no obvious hydrogen peroxide accumulation was observed, in intact CWC during storage.

  15. PROPULSE 980: A Hydrogen Peroxide Enrichment System

    NASA Technical Reports Server (NTRS)

    Boxwell, Robert; Bromley, G.; Wanger, Robert; Pauls, Dan; Maynard, Bryon; McNeal, Curtis; Dumbacher, D. L. (Technical Monitor)

    2000-01-01

    The PROPULSE 980 unit is a transportable processing plant that enriches aerospace grade hydrogen peroxide from 90% to 98% final concentration. The unit was developed by Degussa-H Is, in cooperation with Orbital, NASA Marshall Space Center, and NASA Stennis Space Center. The system is a self-contained unit that houses all of the process equipment, instrumentation and controls to perform the concentration operation nearly autonomously. It is designed to produce non-bulk quantities of 98% hydrogen peroxide. The enrichment unit design also maintains system, personnel and environmental safety during all aspects of the enrichment process and final product storage. As part of the Propulse 980 checkout and final buyoff, it will be disassembled at the Degussa-H Is Corporation plant in Theodore, AL, transported to the Stennis Space Center, reassembled and subjected to a series of checkout tests to verify design objectives have been met. This paper will summarize the basic project elements and provide an update on the present status of the project.

  16. Facile one-step electrochemical deposition of copper nanoparticles and reduced graphene oxide as nonenzymatic hydrogen peroxide sensor

    NASA Astrophysics Data System (ADS)

    Moozarm Nia, Pooria; Woi, Pei Meng; Alias, Yatimah

    2017-08-01

    For several decades, hydrogen peroxide has exhibited to be an extremely significant analyte as an intermediate in several biological devices as well as in many industrial systems. A straightforward and novel one-step technique was employed to develop a sensitive non-enzymatic hydrogen peroxide (H2O2) sensor by simultaneous electrodeposition of copper nanoparticles (CuNPs) and reduced graphene oxide (rGO). The electroreduction performance of the CuNPs-rGO for hydrogen peroxide detection was studied by cyclic voltammetry (CV) and chronoamperometry (AMP) methods The CuNPs-rGO showed a synergistic effect of reduced graphene oxide and copper nanoparticles towards the electroreduction of hydrogen peroxide, indicating high reduction current. At detection potential of -0.2 V, the CuNPs-rGO sensor demonstrated a wide linear range up to 18 mM with a detection limit of 0.601 mM (S/N = 3). Furthermore, with addition of hydrogen peroxide, the sensor responded very quickly (<3 s). The CuNPs-rGO presents high selectivity, sensitivity, stability and fast amperometric sensing towards hydrogen peroxide which makes it favorable for the development of non-enzymatic hydrogen peroxide sensor.

  17. Volatilization of iodine from nitric acid using peroxide

    DOEpatents

    Cathers, G.I.; Shipman, C.J.

    1975-10-21

    A method for removing radioactive iodine from nitric acid solution by adding hydrogen peroxide to the solution while concurrently holding the solution at the boiling point and distilling hydrogen iodide from the solution is reported.

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

    PubMed

    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.

  19. Considerations for Storage of High Test Hydrogen Peroxide (HTP) Utilizing Non-Metal Containers

    NASA Technical Reports Server (NTRS)

    Moore, Robin E.; Scott, Joseph P.; Wise, Harry

    2005-01-01

    When working with high concentrations of hydrogen peroxide, it is critical that the storage container be constructed of the proper materials, those which will not degrade to the extent that container breakdown or dangerous decomposition occurs. It has been suggested that the only materials that will safely contain the peroxide for a significant period of time are metals of stainless steel construction or aluminum use as High Test Hydrogen Peroxide (HTP) Containers. The stability and decomposition of HTP will be also discussed as well as various means suggested in the literature to minimize these problems. The dangers of excess oxygen generation are also touched upon.

  20. Antibacterial Properties and Mechanism of Activity of a Novel Silver-Stabilized Hydrogen Peroxide

    PubMed Central

    Martin, Nancy L.; Bass, Paul; Liss, Steven N.

    2015-01-01

    Huwa-San peroxide (hydrogen peroxide; HSP) is a NSF Standard 60 (maximum 8mg/L-1) new generation peroxide stabilized with ionic silver suitable for continuous disinfection of potable water. Experiments were undertaken to examine the mechanism of HSP against planktonic and biofilm cultures of indicator bacterial strains. Contact/kill time (CT) relationships that achieve effective control were explored to determine the potential utility in primary disinfection. Inhibitory assays were conducted using both nutrient rich media and a medium based on synthetic wastewater. Assays were compared for exposures to three disinfectants (HSP, laboratory grade hydrogen peroxide (HP) and sodium hypochlorite) at concentrations of 20 ppm (therefore at 2.5 and 5 times the NSF limit for HP and sodium hypochlorite, respectively) and at pH 7.0 and 8.5 in dechlorinated tap water. HSP was found to be more or equally effective as hypochlorite or HP. Results from CT assays comparing HSP and HP at different bacterial concentrations with neutralization of residual peroxide with catalase suggested that at a high bacterial concentration HSP, but not HP, was protected from catalase degradation possibly through sequestration by bacterial cells. Consistent with this hypothesis, at a low bacterial cell density residual HSP was more effectively neutralized as less HSP was associated with bacteria and therefore accessible to catalase. Silver in HSP may facilitate this association through electrostatic interactions at the cell surface. This was supported by experiments where the addition of mono (K+) and divalent (Ca+2) cations (0.005-0.05M) reduced the killing efficacy of HSP but not HP. Experiments designed to distinguish any inhibitory effect of silver from that of peroxide in HSP were carried out by monitoring the metabolic activity of established P. aeruginosa PAO1 biofilms. Concentrations of 70-500 ppm HSP had a pronounced effect on metabolic activity while the equivalent concentrations of ionic

  1. Comparison of hydrogen peroxide and peracetic acid as isolator sterilization agents in a hospital pharmacy.

    PubMed

    Bounoure, Frederic; Fiquet, Herve; Arnaud, Philippe

    2006-03-01

    The efficacy of hydrogen peroxide and peracetic acid as isolator sterilization agents was compared. Sterilization and efficacy tests were conducted in a flexible 0.8-m3 transfer isolator using a standard load of glass bottles and sterile medical devices in their packing paper. Bacillus stearothermophilus spores were placed in six critical locations of the isolator and incubated at 55 degrees C in a culture medium for 14 days. Sterilization by 4.25 mL/m3 of 33% vapor-phase hydrogen peroxide and 12.5 mL/m3 of 3.5% peracetic acid was tested in triplicate. Sterility was validated for hydrogen peroxide and peracetic acid at 60, 90, 120, and 180 minutes and at 90, 120, 150, 180, 210, and 240 minutes, respectively. In an efficacy test conducted with an empty isolator, the sterilization time required to destroy B. stearothermophilus spores was 90 minutes for both sterilants, indicating that they have comparable bactericidal properties. During the validation test with a standard load, the sterilization time using hydrogen peroxide was 150 minutes versus 120 minutes with peracetic acid. The glove cuff was particularly difficult for hydrogen peroxide to sterilize, likely due to its slower diffusion time than that of peracetic acid. Hydrogen peroxide is an environmentally safer agent than peracetic acid; however, its bacteriostatic properties, lack of odor, and poor diffusion time may limit its use in sterilizing some materials. Hydrogen peroxide is a useful alternative to peracetic acid for isolator sterilization in a hospital pharmacy or parenteral nutrition preparation unit.

  2. Effect of quercetin and genistein on copper- and iron-induced lipid peroxidation in methyl linolenate.

    PubMed

    Boadi, William Y; Iyere, Peter A; Adunyah, Samuel E

    2003-01-01

    The single and combined effects of two abundant flavonoids, namely quercetin and genistein, were investigated according to their ability to inhibit the oxidation of methyl linolenate via Fenton's pathway. Antioxidative activity was determined by oxidizing methyl linolenate suspended in a buffer solution with either Fe2+ (50 microM) or Cu2+ (50 microM) and hydrogen peroxide (0.01 mM) without or with a flavonoid sample (10 or 20 microM). Lipid peroxidation products were measured by the thiobarbituric acid (TBA) assay and the amounts of thiobarbituric acid-reactive substances (TBARS) were calculated from a calibration curve using 1,1,3,3-tetraethoxypropane as the standard. Both quercetin and genistein at the 10 or 20 microM level decreased lipid peroxidation significantly compared with their respective controls. Of the two flavonoids tested, quercetin had a more marked effect on inhibiting lipid peroxides. Peroxidation products for the control samples were higher for the Fe2+-treated samples compared with the Cu2+ samples. Combination of both flavonoids at the same dose levels continued to decrease lipid peroxidation, the effect being the same for both metal ions. The data suggest that the combined flavonoids offered better protection than the single treatments and this may be attributed to the better radical scavenging or increased chelating capabilities of the combined over the single treatments. The differences in peroxide levels for the single treatment of quercetin compared with the genistein-treated samples may reflect the structural differences between these compounds in combating oxidative stress. Copyright 2003 John Wiley & Sons, Ltd.

  3. Effect of ultrasonic pre-treatment of thermomechanical pulp on hydrogen peroxide bleaching

    NASA Astrophysics Data System (ADS)

    Loranger, E.; Charles, A.; Daneault, C.

    2012-12-01

    Ultrasound pre-treatments of softwood TMP had been carried to evaluate its impact on the efficiency of hydrogen peroxide bleaching. The trials were performed after a factorial design of experiment using frequency, power and time as variables. The experiments were conducted in an ultrasonic bath and then bleached with hydrogen peroxide. Measurements such as brightness, L*A*B* color system coordinate, residual hydrogen peroxide and metal content were evaluated on bleached pulp. The results indicate that the effect of ultrasonic treatment on brightness was dependent on the ultrasound frequency used; the brightness increased slightly at 68 kHz and decreased at 40 and 170 kHz. These results were correlated to the ultrasound effect on the generation of transition metals (copper, iron and manganese) which are responsible for catalytic decomposition of hydrogen peroxide. The influence of metal interference was minimized by using a chelating agent such as diethylene triamine pentaacetic acid (DTPA). With the results obtained in this study we have identified a set of option conditions, e.g. 1000 W, 40 kHz, 1.5 % consistency and 0.2% addition of DTPA prior to the bleaching stage (after ultrasonic pre-treatment) who improve brightness by 2.5 %ISO.

  4. Short communication: The influence of solids concentration and bleaching agent on bleaching efficacy and flavor of sweet whey powder.

    PubMed

    Jervis, M G; Smith, T J; Drake, M A

    2015-04-01

    Recent studies have demonstrated the effect of bleaching conditions and bleaching agent on flavor and functional properties of whey protein ingredients. Solids concentration at bleaching significantly affected bleaching efficacy and flavor effects of different bleaching agents. It is not known if these parameters influence quality of sweet whey powder (SWP). The purpose of this study was to determine the effects of solids concentration and bleaching agent on the flavor and bleaching efficacy of SWP. Colored cheddar whey was manufactured, fat separated, and pasteurized. Subsequently, the whey (6.7% solids) was bleached, concentrated using reverse osmosis (RO) to 14% solids, and then spray dried, or whey was concentrated before bleaching and then spray dried. Bleaching treatments included a control (no bleaching, 50 °C, 60 min), hydrogen peroxide (HP; 250 mg/kg, 50 °C, 60 min), benzoyl peroxide (50 mg/kg, 50 °C, 60 min), lactoperoxidase (20 mg/kg of HP, 50 °C, 30 min), and external peroxidase (MaxiBright, DSM Food Specialties, Delft, the Netherlands; 2 dairy bleaching units/mL, 50 °C, 30 min). The experiment was repeated in triplicate. Sensory properties and volatile compounds of SWP were evaluated by a trained panel and gas chromatography-mass spectrometry, respectively. Bleaching efficacy (norbixin destruction) and benzoic acid were measured by HPLC. Differences in bleaching efficacy, sensory and volatile compound profiles, and benzoic acid were observed with different bleaching agents, consistent with previous studies. Solids concentration affected bleaching efficacy of HP, but not other bleaching agents. The SWP from whey bleached with HP or lactoperoxidase following RO had increased cardboard and fatty flavors and higher concentrations of lipid oxidation compounds compared with SWP from whey bleached before RO. The SWP bleached with benzoyl peroxide after RO contained less benzoic acid than SWP from whey bleached before RO. These results indicate that

  5. Identification and characterization of the tungsten-containing class of benzoyl-coenzyme A reductases

    PubMed Central

    Kung, Johannes W.; Löffler, Claudia; Dörner, Katerina; Heintz, Dimitri; Gallien, Sébastien; Van Dorsselaer, Alain; Friedrich, Thorsten; Boll, Matthias

    2009-01-01

    Aromatic compounds are widely distributed in nature and can only be biomineralized by microorganisms. In anaerobic bacteria, benzoyl-CoA (BCoA) is a central intermediate of aromatic degradation, and serves as substrate for dearomatizing BCoA reductases (BCRs). In facultative anaerobes, the mechanistically difficult reduction of BCoA to cyclohexa-1,5-dienoyl-1-carboxyl-CoA (dienoyl-CoA) is driven by a stoichiometric ATP hydrolysis, catalyzed by a soluble, three [4Fe-4S] cluster-containing BCR. In this work, an in vitro assay for BCR from the obligately anaerobic Geobacter metallireducens was established. It followed the reverse reaction, the formation of BCoA from dienoyl-CoA in the presence of various electron acceptors. The benzoate-induced activity was highly specific for dienoyl-CoA (Km = 24 ± 4 μM). The corresponding oxygen-sensitive enzyme was purified by several chromatographic steps with a 115-fold enrichment and a yield of 18%. The 185-kDa enzyme comprised 73- and 20-kDa subunits, suggesting an α2β2-composition. MS analysis revealed the subunits as products of the benzoate-induced bamBC genes. The αβ unit contained 0.9 W, 15 Fe, and 12.5 acid-labile sulfur. Results from EPR spectroscopy suggest the presence of one [3Fe-4S]0/+1 and three [4Fe-4S]+1/+2 clusters per αβ unit; oxidized BamBC exhibited an EPR signal typical for a W(V) species. The FeS clusters and the W- cofactor could only be fully reduced by dienoyl-CoA. BamBC represents the prototype of a previously undescribed class of dearomatizing BCRs that differ completely from the ATP-dependent enzymes from facultative anaerobes. PMID:19815533

  6. EQCM analysis of titanium corrosion in peroxide- or fluoride-containing solutions.

    PubMed

    Hattori, Masayuki; Oda, Yutaka

    2013-01-01

    Although offering superior resistance to corrosion, titanium is unable to withstand discoloration with exposure to peroxide or fluoride. The mechanism of this discoloration, however, remains to be clarified. The purpose of this study was to investigate the mechanism underlying discoloration of titanium with immersion in peroxide- or fluoride-containing solutions based on electrochemical quartz crystal microbalance (EQCM) analysis. A 9-MHz titanium-deposited quartz crystal was used as for the electrodes. Four test solutions were prepared for immersion of the electrodes: 154 mM (0.9%) NaCl; 150 mM H2O2+154 mM NaCl (pH=4 by addition of lactic acid); 150 mM H2O2+154 mM NaCl (pH=8 by addition of sodium hydroxide solution); and 48 mM (0.2%) NaF+154 mM NaCl (pH=5.0 by addition of lactic acid). A WinEchem electrochemistry software-controlled quartz crystal analyzer (QCA922) and the Potentiostat/Galvanostat (Princeton Applied Research) on Windows XP were used to measure concurrently the resonance frequency and potential of the electrodes. The EQCM data differed among solutions. In the acidulated fluoride-containing solution, the electrode showed lower open circuit potential and a gradual increase in electrode frequency, indicating a loss of mass by titanium dissolution. In the peroxide-containing solution, although open circuit potential showed no marked difference, electrode frequency showed a gentle decrease in acidic solution, indicating a gain in mass by oxidation; but an increase in alkaline solution, indicating a loss of mass by dissolution. These results confirmed that exposure to acidulated fluoride- or alkaline peroxide-containing solutions causes dissolution-induced discoloration, while that to acidulated peroxide-containing solutions resulted in the formation of an oxide film together with discoloration.

  7. Role of indigenous iron in improving sludge dewaterability through peroxidation

    PubMed Central

    Zhou, Xu; Jiang, Guangming; Wang, Qilin; Yuan, Zhiguo

    2015-01-01

    Improvement of sludge dewaterability is important for reducing the total costs for the treatment and disposal of sludge in wastewater treatment plants. In this study, we investigate the use of hydrogen peroxide as an oxidizing reagent for the conditioning of waste activated sludge. Significant improvement to sludge dewaterability was attained after the addition of hydrogen peroxide at 30 mg/g TS and 28 mg/g TS under acidic conditions (pH = 3.0), with the highest reduction of capillary suction time being 68% and 56%, respectively, for sludge containing an iron concentration of 56 mg Fe/g TS and 25 mg Fe/g TS, respectively. The observations were due to Fenton reactions between the iron contained in sludge (indigenous iron) and hydrogen peroxide. For the sludge with an insufficient level of indigenous iron, the addition of ferrous chloride was found to be able to improve the sludge dewaterability. The results firstly indicated that indigenous iron can be utilized similarly as the externally supplied iron salt to improve sludge dewaterability through catalyzing the Fenton reactions. PMID:25559367

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

    PubMed

    Alexandrova, M; Rozhko, T; Vydryakova, G; Kudryasheva, N

    2011-04-01

    The effect of americium-241 ((241)Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of (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 °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 (241)Am is discussed. The effect of (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 (241)Am solutions was demonstrated; and the similarity of (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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Safety issues of high-concentrated hydrogen peroxide production used as rocket propellant

    NASA Astrophysics Data System (ADS)

    Romantsova, O. V.; Ulybin, V. B.

    2015-04-01

    The article dwells on the possibility of production of high-concentrated hydrogen peroxide with the Russian technology of isopropyl alcohol autoxidation. Analysis of fire/explosion hazards and reasons of insufficient quality is conducted for the technology. Modified technology is shown. Non-standard fire/explosion characteristics required for integrated fire/explosion hazards rating for modified hydrogen peroxide production based on the autoxidation of isopropyl alcohol are defined.

  10. Synthesis, spectroscopic and structural characterization of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine with theoretical calculations using density functional theory

    NASA Astrophysics Data System (ADS)

    İnkaya, Ersin; Dinçer, Muharrem; Şahan, Emine; Yıldırım, İsmail

    2013-10-01

    In this paper, we will report a combined experimental and theoretical investigation of the molecular structure and spectroscopic parameters (FT-IR, 1H NMR, 13C NMR) of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine. The compound crystallizes in the triclinic space group P-1 with Z = 2. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311G(d,p) and 6-311++G(d,p) basis sets in ground state and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential (ESP). Also, non-linear optical properties of the title compound were performed at B3LYP/6-311++G(d,p) level. The theoretical results showed an excellent agreement with the experimental values.

  11. Glycerophosphate-dependent hydrogen peroxide production by rat liver mitochondria.

    PubMed

    Jesina, P; Kholová, D; Bolehovská, R; Cervinková, Z; Drahota, Z; Houstek, J

    2004-01-01

    We studied the extent to which hormonally-induced mitochondrial glycerophosphate dehydrogenase (mGPDH) activity contributes to the supply of reducing equivalents to the mitochondrial respiratory chain in the rat liver. The activity of glycerophosphate oxidase was compared with those of NADH oxidase and/or succinate oxidase. It was found that triiodothyronine-activated mGPDH represents almost the same capacity for the saturation of the respiratory chain as Complex II. Furthermore, the increase of mGPDH activity induced by triiodothyronine correlated with an increase of capacity for glycerophosphate-dependent hydrogen peroxide production. As a result of hormonal treatment, a 3-fold increase in glycerophosphate-dependent hydrogen peroxide production by liver mitochondria was detected by polarographic and luminometric measurements.

  12. Fish oil changes the lifespan of Caenorhabditis elegans via lipid peroxidation

    PubMed Central

    Sugawara, Soko; Honma, Taro; Ito, Junya; Kijima, Ryo; Tsuduki, Tsuyoshi

    2013-01-01

    Recently, we administered fish oil containing eicosapentaenoic acid and docosahexaenoic acid (DHA) to senescence-accelerated mice P8 (SAMP8), in order to investigate the effects on lifespan. Surprisingly, the lifespan of SAMP8 that were fed fish oil was shortened significantly, through a mechanism that likely involved lipid peroxidation. In this study, we investigated this phenomenon in further detail. To examine whether this phenomenon occurs only in SAMP8, we investigated the effect of fish oil on the lifespan of another organism species, Caenorhabditis elegans (C. elegans). C. elegans fed fish oil were cultured and the lifespan monitored. As a consequence of the provision of large amounts of fish oil the lifespan of C. elegans was shortened significantly, whereas an appropriate amount of fish oil extended their lifespan significantly. Lipid peroxide levels in C. elegans that were fed fish oil increased significantly in a dose-dependent manner. However, lipid peroxide levels in C. elegans were inhibited by the addition of fish oil and an antioxidant, α-tocopherol, and completely abrogated the changes in the lifespan. To further confirm whether the oxidation of n-3 polyunsaturated fatty acid in fish oil would change the lifespan of C. elegans, the effect of oxidized DHA was examined. Large amounts of oxidized DHA were found to shorten their lifespan significantly. Thus, fish oil changes the lifespan of C. elegans through lipid peroxidation. PMID:23526170

  13. Hydrogen peroxide toxicity induces Ras signaling in human neuroblastoma SH-SY5Y cultured cells.

    PubMed

    Chetsawang, Jirapa; Govitrapong, Piyarat; Chetsawang, Banthit

    2010-01-01

    It has been reported that overproduction of reactive oxygen species occurs after brain injury and mediates neuronal cells degeneration. In the present study, we examined the role of Ras signaling on hydrogen peroxide-induced neuronal cells degeneration in dopaminergic neuroblastoma SH-SY5Y cells. Hydrogen peroxide significantly reduced cell viability in SH-SY5Y cultured cells. An inhibitor of the enzyme that catalyzes the farnesylation of Ras proteins, FTI-277, and a competitive inhibitor of GTP-binding proteins, GDP-beta-S significantly decreased hydrogen peroxide-induced reduction in cell viability in SH-SY5Y cultured cells. The results of this study might indicate that a Ras-dependent signaling pathway plays a role in hydrogen peroxide-induced toxicity in neuronal cells.

  14. Bactericidal Efficacy of Hydrogen Peroxide-Based Disinfectants Against Gram-Positive and Gram-Negative Bacteria on Stainless Steel Surfaces.

    PubMed

    Ríos-Castillo, Abel G; González-Rivas, Fabián; Rodríguez-Jerez, José J

    2017-10-01

    In order to develop disinfectant formulations that leverage the effectiveness of hydrogen peroxide (H 2 O 2 ), this study evaluated the bactericidal efficacy of hydrogen peroxide-based disinfectants against Gram-positive and Gram-negative bacteria on stainless steel surfaces. Low concentration of hydrogen peroxide as 0.5% with a cationic polymer, ethoxylated fatty alcohol, and ethyl alcohol had bactericidal efficacy (reductions ≥ 4 log 10 CFU/mL) against Escherichia coli, Staphylococcus aureus, Enterococcus hirae, and Pseudomonas aeruginosa. Hydrogen peroxide-based disinfectants were more effective against E. hirae and P. aeruginosa than to S. aureus. However, the efficacy of hydrogen peroxide against catalase positive bacteria such as S. aureus was increased when this compound was formulated with low concentrations of benzalkonium chloride or ethyl alcohol, lactic acid, sodium benzoate, cationic polymer, and salicylic acid. This study demonstrates that the use of hydrogen peroxide with other antimicrobial products, in adequate concentrations, had bactericidal efficacy in Gram-positive and Gram-negative bacteria on stainless steel surfaces, enabling to reduce the effective concentration of hydrogen peroxide. In the same way, the use of hydrogen peroxide-based disinfectants could reduce the concentrations of traditional disinfectants as quaternary ammonium compounds and therefore a reduction of their chemical residues in the environment after being used. The study of the bactericidal properties of environmentally nontoxic disinfectants such as hydrogen peroxide, sole or in formulations with other disinfectants against Gram-positive and Gram-negative bacteria can enhance the efficacy of various commonly used disinfectant formulations with the hygiene benefits that it entails. Also, the use of hydrogen peroxide formulations can reduce the concentration levels of products that generate environmental residues. © 2017 Institute of Food Technologists®.

  15. Oxygen-consuming chlor alkali cell configured to minimize peroxide formation

    DOEpatents

    Chlistunoff, Jerzy B [Los Alamos, NM; Lipp, Ludwig [Brookfield, CT; Gottesfeld, Shimshon [Niskayuna, NY

    2006-08-01

    Oxygen-consuming zero gap chlor-alkali cell was configured to minimize peroxide formation. The cell included an ion-exchange membrane that divided the cell into an anode chamber including an anode and a cathode chamber including an oxygen gas diffusion cathode. The cathode included a single-piece of electrically conducting graphitized carbon cloth. Catalyst and polytetrafluoroethylene were attached to only one side of the cloth. When the cathode was positioned against the cation exchange membrane with the catalyst side away from the membrane, electrolysis of sodium chloride to chlorine and caustic (sodium hydroxide) proceeded with minimal peroxide formation.

  16. Alkaline Peroxide Delignification of Corn Stover

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mittal, Ashutosh; Katahira, Rui; Donohoe, Bryon S.

    Selective biomass fractionation into carbohydrates and lignin is a key challenge in the conversion of lignocellulosic biomass to fuels and chemicals. In the present study, alkaline hydrogen peroxide (AHP) pretreatment was investigated to fractionate lignin from polysaccharides in corn stover (CS), with a particular emphasis on the fate of the lignin for subsequent valorization. The influence of peroxide loading on delignification during AHP pretreatment was examined over the range of 30-500 mg H2O2/g dry CS at 50 degrees C for 3 h. Mass balances were conducted on the solid and liquid fractions generated after pretreatment for each of the threemore » primary components, lignin, hemicellulose, and cellulose. AHP pretreatment at 250 mg H2O2/g dry CS resulted in the pretreated solids with more than 80% delignification consequently enriching the carbohydrate fraction to >90%. Two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy of the AHP pretreated residue shows that, under high peroxide loadings (>250 mg H2O2/g dry CS), most of the side chain structures were oxidized and the aryl-ether bonds in lignin were partially cleaved, resulting in significant delignification of the pretreated residues. Gel permeation chromatography (GPC) analysis shows that AHP pretreatment effectively depolymerizes CS lignin into low molecular weight (LMW) lignin fragments in the aqueous fraction. Imaging of AHP pretreated residues shows a more granular texture and a clear lamellar pattern in secondary walls, indicative of layers of varying lignin removal or relocalization. Enzymatic hydrolysis of this pretreated residue at 20 mg/g of glucan resulted in 90% and 80% yields of glucose and xylose, respectively, after 120 h. Overall, AHP pretreatment is able to selectively remove more than 80% of the lignin from biomass in a form that has potential for downstream valorization processes and enriches the solid pulp into a highly digestible material.« less

  17. Efficacy of hydrogen peroxide in controlling mortality associated with saprolegniasis on walleye, white sucker, and paddlefish eggs

    USGS Publications Warehouse

    Gaikowski, M.P.; Rach, J.J.; Drobish, M.; Hamilton, J.; Harder, T.; Lee, L.A.; Moen, C.; Moore, A.

    2003-01-01

    The efficacy of hydrogen peroxide in controlling saprolegniasis on eggs of walleye Stizostedion vitreum, white sucker Catostomus commersoni, and paddlefish Polyodon spathula was evaluated at four private, state, and federal production hatcheries participating in an Investigational New Animal Drug efficacy study (experiment 1; walleyes) and in a laboratory-based miniature egg jar incubation system (experiment 2; walleyes, white suckers, and paddlefish). Naturally occurring fungal infestations (saprolegniasis) were observed on eggs in both experiments. Confirmatory diagnosis of infested eggs from one hatchery in experiment 1 identified the pathogen as Saprolegnia parasitica. During experiment 1, eggs were treated daily for 15 min with either 0, 500, or 750 mg/L of hydrogen peroxide, and one trial compared a 500-mg/L hydrogen peroxide treatment with a formalin treatment at 1,667 mg/L. Saprolegniasis infestation was observed in control egg jars, whereas treatment with either formalin or hydrogen peroxide virtually eliminated the infestation. Hydrogen peroxide treatments of 500 mg/L either increased egg hatch or were as effective as physical removal of infested eggs in controlling mortality. Although treatment with formalin at 1,667 mg/L significantly increased the percent eye-up of walleye eggs compared with that of those treated with hydrogen peroxide at 500 mg/L, the difference was only 1.9-2.6%. In experiment 2, noneyed eggs were treated for 15 min every other day with 0, 283, 565, or 1,130 mg/L of hydrogen peroxide until the viable eggs hatched. Saprolegniasis infestation engulfed most control eggs, whereas infestation of treated eggs was either reduced or not visible. Hydrogen peroxide significantly increased egg hatch for all three species tested in experiment 2. Although hydrogen peroxide treatments as low as 283 mg/L significantly increased walleye and white sucker hatch, treatments between 500 and 1,000 mg/L are more likely to be effective in production egg

  18. Potential for free radical-induced lipid peroxidation as a cause of endothelial cell injury in Rocky Mountain spotted fever.

    PubMed Central

    Silverman, D J; Santucci, L A

    1988-01-01

    Cells infected by Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, display unusual intracellular morphological changes characterized by dilatation of the membranes of the endoplasmic reticulum and outer nuclear envelope. These changes are consistent with those that might be expected to occur following peroxidation of membrane lipids initiated by oxygen radical species, such as the hydroxyl radical or a variety of organic radicals. Using a fluorescent probe, we have found significantly increased levels of peroxides in human endothelial cells infected by R. rickettsii. Studies with desferrioxamine, an iron chelator effective in preventing formation of the hydroxyl radical from hydrogen peroxide and the superoxide free radical, reduced peroxide levels in infected cells to those found in uninfected cells. This observation suggests that the increased peroxides in infected cells may be lipid peroxides, degradation products of free radical attack on polyenoic fatty acids. The potential for lipid peroxidation as an important mechanism in endothelial cell injury caused by R. rickettsii is discussed. Images PMID:3141280

  19. An Experimental Investigation of Hypergolic Ignition Delay of Hydrogen Peroxide with Fuel Mixtures

    NASA Technical Reports Server (NTRS)

    Blevins, John A.; Gostowski, Rudy; Chianese, Silvio

    2003-01-01

    An experimental evaluation of decomposition and ignition delay of hydrogen peroxide at concentrations of 80% to 98% with combinations of hydrocarbon fuels, tertiary amines and transition metal chelates will be presented in the proposed paper. The results will be compared to hydrazine ignition delays with hydrogen peroxide and nitric acid mixtures using the same test apparatus.

  20. Organic hydrogen peroxide-driven low charge potentials for high-performance lithium-oxygen batteries with carbon cathodes

    PubMed Central

    Wu, Shichao; Qiao, Yu; Yang, Sixie; Ishida, Masayoshi; He, Ping; Zhou, Haoshen

    2017-01-01

    Reducing the high charge potential is a crucial concern in advancing the performance of lithium-oxygen batteries. Here, for water-containing lithium-oxygen batteries with lithium hydroxide products, we find that a hydrogen peroxide aqueous solution added in the electrolyte can effectively promote the decomposition of lithium hydroxide compounds at the ultralow charge potential on a catalyst-free Ketjen Black-based cathode. Furthermore, for non-aqueous lithium-oxygen batteries with lithium peroxide products, we introduce a urea hydrogen peroxide, chelating hydrogen peroxide without any water in the organic, as an electrolyte additive in lithium-oxygen batteries with a lithium metal anode and succeed in the realization of the low charge potential of ∼3.26 V, which is among the best levels reported. In addition, the undesired water generally accompanying hydrogen peroxide solutions is circumvented to protect the lithium metal anode and ensure good battery cycling stability. Our results should provide illuminating insights into approaches to enhancing lithium-oxygen batteries. PMID:28585527

  1. CALCIUM-INDUCED LIPID PEROXIDATION IS MEDIATED BY RHODNIUS HEME-BINDING PROTEIN (RHBP) AND PREVENTED BY VITELLIN.

    PubMed

    Paes, Marcia C; Silveira, Alan B; Ventura-Martins, Guilherme; Luciano, Monalisa; Coelho, Marsen G P; Todeschini, Adriane R; Bianconi, M Lucia; Atella, Georgia C; Silva-Neto, Mário A C

    2015-10-01

    Lipid peroxidation is promoted by the quasi-lipoxygenase (QL) activity of heme proteins and enhanced by the presence of free calcium. Unlike mammalian plasma, the hemolymph of Rhodnius prolixus, a vector of Chagas disease, contains both a free heme-binding protein (RHBP) and circulating lipoproteins. RHBP binds and prevents the heme groups of the proteins from participating in lipid peroxidation reactions. Herein, we show that despite being bound to RHBP, heme groups promote lipid peroxidation through a calcium-dependent QL reaction. This reaction is readily inhibited by the presence of ethylene glycol tetraacetic acid (EGTA), the antioxidant butylated hydroxytoluene or micromolar levels of the main yolk phosphoprotein vitellin (Vt). The inhibition of lipid peroxidation is eliminated by the in vitro dephosphorylation of Vt, indicating that this reaction depends on the interaction of free calcium ions with negatively charged phosphoamino acids. Our results demonstrate that calcium chelation mediated by phosphoproteins occurs via an antioxidant mechanism that protects living organisms from lipid peroxidation. © 2015 Wiley Periodicals, Inc.

  2. Organic hydrogen peroxide-driven low charge potentials for high-performance lithium-oxygen batteries with carbon cathodes

    NASA Astrophysics Data System (ADS)

    Wu, Shichao; Qiao, Yu; Yang, Sixie; Ishida, Masayoshi; He, Ping; Zhou, Haoshen

    2017-06-01

    Reducing the high charge potential is a crucial concern in advancing the performance of lithium-oxygen batteries. Here, for water-containing lithium-oxygen batteries with lithium hydroxide products, we find that a hydrogen peroxide aqueous solution added in the electrolyte can effectively promote the decomposition of lithium hydroxide compounds at the ultralow charge potential on a catalyst-free Ketjen Black-based cathode. Furthermore, for non-aqueous lithium-oxygen batteries with lithium peroxide products, we introduce a urea hydrogen peroxide, chelating hydrogen peroxide without any water in the organic, as an electrolyte additive in lithium-oxygen batteries with a lithium metal anode and succeed in the realization of the low charge potential of ~3.26 V, which is among the best levels reported. In addition, the undesired water generally accompanying hydrogen peroxide solutions is circumvented to protect the lithium metal anode and ensure good battery cycling stability. Our results should provide illuminating insights into approaches to enhancing lithium-oxygen batteries.

  3. Nanostructuring one-dimensional and amorphous lithium peroxide for high round-trip efficiency in lithium-oxygen batteries.

    PubMed

    Dutta, Arghya; Wong, Raymond A; Park, Woonghyeon; Yamanaka, Keisuke; Ohta, Toshiaki; Jung, Yousung; Byon, Hye Ryung

    2018-02-14

    The major challenge facing lithium-oxygen batteries is the insulating and bulk lithium peroxide discharge product, which causes sluggish decomposition and increasing overpotential during recharge. Here, we demonstrate an improved round-trip efficiency of ~80% by means of a mesoporous carbon electrode, which directs the growth of one-dimensional and amorphous lithium peroxide. Morphologically, the one-dimensional nanostructures with small volume and high surface show improved charge transport and promote delithiation (lithium ion dissolution) during recharge and thus plays a critical role in the facile decomposition of lithium peroxide. Thermodynamically, density functional calculations reveal that disordered geometric arrangements of the surface atoms in the amorphous structure lead to weaker binding of the key reaction intermediate lithium superoxide, yielding smaller oxygen reduction and evolution overpotentials compared to the crystalline surface. This study suggests a strategy to enhance the decomposition rate of lithium peroxide by exploiting the size and shape of one-dimensional nanostructured lithium peroxide.

  4. Towards the fluorogenic detection of peroxide explosives through host–guest chemistry

    PubMed Central

    Almenar, Estefanía; Costero, Ana M.; Gil, Salvador; Parra, Margarita

    2018-01-01

    Two dansyl-modified β-cyclodextrin derivatives (1 and 2) have been synthesized as host–guest sensory systems for the direct fluorescent detection of the peroxide explosives diacetone diperoxide (DADP) and triacetone triperoxide (TATP) in aqueous media. The sensing is based on the displacement of the dansyl moiety from the cavity of the cyclodextrin by the peroxide guest resulting in a decrease of the intensity of the fluorescence of the dye. Both systems showed similar fluorescent responses and were more sensitive towards TATP than DADP. PMID:29765646

  5. Towards the fluorogenic detection of peroxide explosives through host-guest chemistry.

    PubMed

    Almenar, Estefanía; Costero, Ana M; Gaviña, Pablo; Gil, Salvador; Parra, Margarita

    2018-04-01

    Two dansyl-modified β-cyclodextrin derivatives ( 1 and 2 ) have been synthesized as host-guest sensory systems for the direct fluorescent detection of the peroxide explosives diacetone diperoxide (DADP) and triacetone triperoxide (TATP) in aqueous media. The sensing is based on the displacement of the dansyl moiety from the cavity of the cyclodextrin by the peroxide guest resulting in a decrease of the intensity of the fluorescence of the dye. Both systems showed similar fluorescent responses and were more sensitive towards TATP than DADP.

  6. Power generation in fuel cells using liquid methanol and hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Narayanan, Sekharipuram R. (Inventor); Valdez, Thomas I. (Inventor); Chun, William (Inventor)

    2002-01-01

    The invention is directed to an encapsulated fuel cell including a methanol source that feeds liquid methanol (CH.sub.3 OH) to an anode. The anode is electrical communication with a load that provides electrical power. The fuel cell also includes a hydrogen peroxide source that feeds liquid hydrogen peroxide (H.sub.2 O.sub.2) to the cathode. The cathode is also in communication with the electrical load. The anode and cathode are in contact with and separated by a proton-conducting polymer electrolyte membrane.

  7. Use of hydrogen peroxide during incubation of landlocked fall Chinook salmon eggs in vertical-flow incubators

    USGS Publications Warehouse

    Barnes, M.E.; Gaikowski, M.P.

    2004-01-01

    Six different hydrogen peroxide treatment regimes were evaluated in a series of three trials with landlocked fall Chinook salmon Oncorhynchus tshawytscha eggs incubated in vertical-flow incubators. Six daily 15-min hydrogen peroxide treatment regimes (1,000 mg/L; 1,000 mg/L with a decrease to 500 mg/L during estimated blastopore formation; 2,000 mg/L; 2,000 mg/L with a decrease to 500 mg/L during estimated blastopore formation; 2,500 mg/L; and 2,500 mg/L with a decrease to 500 mg/L during estimated blastopore formation) were compared with daily 15-min treatments of 1,667 mg/L of formalin. Mortality at egg eye-up and fry hatch and from eye-up to hatch was significantly greater in eggs receiving the 2,500-mg/L hydrogen peroxide treatments throughout incubation and in those receiving 2,500 mg/L hydrogen peroxide with a decrease to 500 mg/L during blastopore formation than in either of the 1,000-mg/L hydrogen peroxide treatment regimes or the formalin-treated eggs in the first trial. No significant differences in mortality were observed among any of the treatments in the subsequent two trials with maximum hydrogen peroxide concentrations of 2,000 mg/L. Fungal infestations were observed primarily in the incubation trays treated at either of the 1,000-mg/L hydrogen peroxide regimens, as well as in those trays whose treatment concentrations were dropped to 500 mg/L during blastopore formation. Infestations were not observed in any of the formalin-treated trays. If minor fungal infestation is acceptable, then daily hydrogen peroxide treatments of 1,000 mg/L for 15 min would probably provide adequate fungal control compared with formalin usage.

  8. Placebo-controlled clinical trial of use of 10% hydrogen peroxide whitening strips for medication-induced xerostomia.

    PubMed

    Papas, Athena S; Kugel, Gerard; Singh, Mabi; Barker, Matthew L; Gerlach, Robert W

    2009-01-01

    A randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the effectiveness and safety of peroxide-containing strip-based tooth whitening among subjects with medication-induced hyposalivation. Eligibility for this tooth whitening study was limited to dentate adults taking xerogenic medications with an unstimulated salivary flow < or = 0.2 ml/min. After giving informed consent, 42 subjects were randomized using a 2:1 ratio to 10% hydrogen peroxide whitening strips (Crest Whitestrips Premium) or placebo strips without peroxide. Strips were used for 30 min twice daily for a 14-day period. Usage was unsupervised, and only the maxillary arch was treated. On days 8 and 15, efficacy was assessed from standard digital images of the anterior dentition and quantified using the Cielab color system, while safety was assessed from interviews and clinical examinations. At day 8, the peroxide group experienced significant (p < 0.001) color improvement relative to baseline and placebo. Adjusted means +/- standard errors for yellowness reduction were -1.65 +/- 0.115 units for the peroxide group and -0.32 +/- 0.170 units for the placebo group. For the increase in lightness, adjusted means +/- standard errors on day 8 were 1.53 +/- 0.130 units for the peroxide group and 0.37 +/- 0.191 units for the controls. Continued strip use through day 15 yielded incremental color improvement for the peroxide group. Mild and transient tooth sensitivity represented the most common adverse events. No subject discontinued treatment due to a product-related adverse event. Twice daily use of 10% hydrogen peroxide whitening strips by adults with medication-induced xerostomia was well tolerated, with significant tooth color improvement evident within 7 days. Copyright 2009 S. Karger AG, Basel.

  9. Hydrogen peroxide production is affected by oxygen levels in mammalian cell culture.

    PubMed

    Maddalena, Lucas A; Selim, Shehab M; Fonseca, Joao; Messner, Holt; McGowan, Shannon; Stuart, Jeffrey A

    2017-11-04

    Although oxygen levels in the extracellular space of most mammalian tissues are just a few percent, under standard cell culture conditions they are not regulated and are often substantially higher. Some cellular sources of reactive oxygen species, like NADPH oxidase 4, are sensitive to oxygen levels in the range between 'normal' physiological (typically 1-5%) and standard cell culture (up to 18%). Hydrogen peroxide in particular participates in signal transduction pathways via protein redox modifications, so the potential increase in its production under standard cell culture conditions is important to understand. We measured the rates of cellular hydrogen peroxide production in some common cell lines, including C2C12, PC-3, HeLa, SH-SY5Y, MCF-7, and mouse embryonic fibroblasts (MEFs) maintained at 18% or 5% oxygen. In all instances the rate of hydrogen peroxide production by these cells was significantly greater at 18% oxygen than at 5%. The increase in hydrogen peroxide production at higher oxygen levels was either abolished or substantially reduced by treatment with GKT 137831, a selective inhibitor of NADPH oxidase subunits 1 and 4. These data indicate that oxygen levels experienced by cells in culture influence hydrogen peroxide production via NADPH oxidase 1/4, highlighting the importance of regulating oxygen levels in culture near physiological values. However, we measured pericellular oxygen levels adjacent to cell monolayers under a variety of conditions and with different cell lines and found that, particularly when growing at 5% incubator oxygen levels, pericellular oxygen was often lower and variable. Together, these observations indicate the importance, and difficulty, of regulating oxygen levels experienced by cells in culture. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Transenamel and transdentinal penetration of hydrogen peroxide applied to cracked or microabrasioned enamel.

    PubMed

    Briso, A L F; Lima, A P B; Gonçalves, R S; Gallinari, M O; dos Santos, P H

    2014-01-01

    The present study evaluated transenamel and transdentinal penetration of hydrogen peroxide during tooth whitening recognized in altered enamel by the presence of cracks or microabrasion. We used 72 experimental units (n=20) obtained from bovine incisors: GI-sound enamel; GII-teeth showing visible enamel cracks (4 mm to 5.7 mm in length); and GIII-microabrasioned enamel. The 12 remaining specimens were used to analyze the enamel surface morphology using scanning electron microscopy. The specimens were cylindrical and 5.7 mm in diameter and 3.5 mm thick. A product based on 35% hydrogen peroxide was used for bleaching, following the manufacturer's recommendations for use. To quantify the H2O2 penetration, the specimens were placed in artificial pulp chambers containing an acetate buffer solution. After bleaching, the solution was collected and adequately proportioned with leucocrystal violet, peroxidase enzyme, and deionized water. The resulting solution was evaluated using ultraviolet visible reflectance spectrophotometer equipment. The data were analyzed by analysis of variance (ANOVA) and Fisher's PLSD at a significance level of 0.05, and significant differences in the penetration of peroxide in different substrate conditions were observed (p<0.0001). The penetration of hydrogen peroxide was more intense in cracked teeth. The group in which the enamel was microabraded showed intermediate values when compared to the control group. Microabrasion and the presence of cracks in the enamel make this substrate more susceptible to penetration of hydrogen peroxide during in-office whitening.

  11. Trends in Selective Hydrogen Peroxide Production on Transition Metal Surfaces from First Principles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rankin, Rees B.; Greeley, Jeffrey P.

    2012-10-19

    We present a comprehensive, Density Functional Theory-based analysis of the direct synthesis of hydrogen peroxide, H2O2, on twelve transition metal surfaces. We determine the full thermodynamics and selected kinetics of the reaction network on these metals, and we analyze these energetics with simple, microkinetically motivated rate theories to assess the activity and selectivity of hydrogen peroxide production on the surfaces of interest. By further exploiting Brønsted-Evans-Polanyi relationships and scaling relationships between the binding energies of different adsorbates, we express the results in the form of a two dimensional contour volcano plot, with the activity and selectivity being determined as functionsmore » of two independent descriptors, the atomic hydrogen and oxygen adsorption free energies. We identify both a region of maximum predicted catalytic activity, which is near Pt and Pd in descriptor space, and a region of selective hydrogen peroxide production, which includes Au. The optimal catalysts represent a compromise between activity and selectivity and are predicted to fall approximately between Au and Pd in descriptor space, providing a compact explanation for the experimentally known performance of Au-Pd alloys for hydrogen peroxide synthesis, and suggesting a target for future computational screening efforts to identify improved direct hydrogen peroxide synthesis catalysts. Related methods of combining activity and selectivity analysis into a single volcano plot may be applicable to, and useful for, other aqueous phase heterogeneous catalytic reactions where selectivity is a key catalytic criterion.« less

  12. Application of response surface methodology (RSM) to the optimization of a post-column luminol chemiluminescence analysis of silyl peroxides.

    PubMed

    Baj, Stefan; Słupska, Roksana; Krawczyk, Tomasz

    2013-01-15

    The possibility of the utilization of chemiluminescence post-column luminol oxidation (CL) in a HPLC system for silyl peroxides analysis has been investigated. The conditions of HPLC separation for 12 silyl peroxides, representing bissilyl and alkyl-silyl peroxides, as well as their potential impurities, were established. Optimal chemiluminescent post-column reaction conditions were found using central composite design (CCD) and response surface methodology (RSM). The interaction effects of four of the most important operating variables - the concentrations of luminol, hemin, sodium hydroxide and the post-column solution flow rate - on the light intensity were evaluated. The optimized conditions for analysis were the same for bissilyl and alkyl-silyl peroxides for the base concentration (0.03 M), the luminol concentration (0.4 g L(-1)) and the hemin concentration (0.3 g L(-1)). The only differences occurred in a reagent flow rate (for bissilyl peroxide -0.3 mL min(-1) and for alkyl-silyl peroxides -0.9 mL min(-1)). Under optimal conditions, the detection limits were in the 0.07-0.16 nM range for bissilyl, and 0.53-1.01 for alkyl-silyl peroxides. The calibration curves were linear in the 0.25-3 nM range for bissilyl and the 2.5-25 range for alkyl-silyl peroxides. Intra-day and inter-day precision was lower than 5.5% for each tested concentration level. A mechanism of luminol oxidation by silyl peroxides involving a hydrolysis step with the formation of hydrogen peroxide or hydroperoxide was proposed. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Benzoyl Halides as Alternative Precursors for the Colloidal Synthesis of Lead-Based Halide Perovskite Nanocrystals

    PubMed Central

    2018-01-01

    We propose here a new colloidal approach for the synthesis of both all-inorganic and hybrid organic–inorganic lead halide perovskite nanocrystals (NCs). The main limitation of the protocols that are currently in use, such as the hot injection and the ligand-assisted reprecipitation routes, is that they employ PbX2 (X = Cl, Br, or I) salts as both lead and halide precursors. This imposes restrictions on being able to precisely tune the amount of reaction species and, consequently, on being able to regulate the composition of the final NCs. In order to overcome this issue, we show here that benzoyl halides can be efficiently used as halide sources to be injected in a solution of metal cations (mainly in the form of metal carboxylates) for the synthesis of APbX3 NCs (in which A = Cs+, CH3NH3+, or CH(NH2)2+). In this way, it is possible to independently tune the amount of both cations and halide precursors in the synthesis. The APbX3 NCs that were prepared with our protocol show excellent optical properties, such as high photoluminescence quantum yields, low amplified spontaneous emission thresholds, and enhanced stability in air. It is noteworthy that CsPbI3 NCs, which crystallize in the cubic α phase, are stable in air for weeks without any postsynthesis treatment. The improved properties of our CsPbX3 perovskite NCs can be ascribed to the formation of lead halide terminated surfaces, in which Cs cations are replaced by alkylammonium ions. PMID:29378131

  14. Benzoyl Halides as Alternative Precursors for the Colloidal Synthesis of Lead-Based Halide Perovskite Nanocrystals.

    PubMed

    Imran, Muhammad; Caligiuri, Vincenzo; Wang, Mengjiao; Goldoni, Luca; Prato, Mirko; Krahne, Roman; De Trizio, Luca; Manna, Liberato

    2018-02-21

    We propose here a new colloidal approach for the synthesis of both all-inorganic and hybrid organic-inorganic lead halide perovskite nanocrystals (NCs). The main limitation of the protocols that are currently in use, such as the hot injection and the ligand-assisted reprecipitation routes, is that they employ PbX 2 (X = Cl, Br, or I) salts as both lead and halide precursors. This imposes restrictions on being able to precisely tune the amount of reaction species and, consequently, on being able to regulate the composition of the final NCs. In order to overcome this issue, we show here that benzoyl halides can be efficiently used as halide sources to be injected in a solution of metal cations (mainly in the form of metal carboxylates) for the synthesis of APbX 3 NCs (in which A = Cs + , CH 3 NH 3 + , or CH(NH 2 ) 2 + ). In this way, it is possible to independently tune the amount of both cations and halide precursors in the synthesis. The APbX 3 NCs that were prepared with our protocol show excellent optical properties, such as high photoluminescence quantum yields, low amplified spontaneous emission thresholds, and enhanced stability in air. It is noteworthy that CsPbI 3 NCs, which crystallize in the cubic α phase, are stable in air for weeks without any postsynthesis treatment. The improved properties of our CsPbX 3 perovskite NCs can be ascribed to the formation of lead halide terminated surfaces, in which Cs cations are replaced by alkylammonium ions.

  15. Peroxide accumulation and cell death in filamentous fungi induced by contact with a contestant.

    PubMed

    Silar, Philippe

    2005-02-01

    Podospora anserina and Coprinopsis cinerea (syn. Coprinus cinereus) are endowed with a defence system able to differentiate self vs. non-self and involving the generation of peroxide. Indeed, they produce peroxide when confronted with a filamentous fungus, only in non-self confrontations. Both species are not able to recognize yeasts and show a differential response to bacteria. The accumulation of peroxides in the ascomycete Podospora anserina requires an NADPH oxidase and a MAP kinase cascade, previously shown to be involved in fruit body formation, cell differentiation and cell degeneration. Confrontation is accompanied by the death of the contestant hyphae only in specific combinations of species. As in animals and plants, data suggest that peroxide is likely involved in signalling rather than playing a direct toxic role. Fungi display more complex behaviours than generally acknowledged, i.e. they are able to recognize potential contestants and built up defence reactions involving evolutionary conserved enzymes.

  16. Versatility of azelaic acid 15% gel in treatment of inflammatory acne vulgaris.

    PubMed

    Thiboutot, Diane

    2008-01-01

    Azelaic acid (AzA) 15% gel is approved for the treatment of rosacea in the US, but also has approval for the treatment of acne vulgaris in many European countries where it has demonstrated success. Two randomized, multicenter, controlled clinical trials compared the effects of AzA 15% gel with those of topical benzoyl peroxide 5% or topical clindamycin 1%, all using a twice-daily dosing regimen. The primary endpoint in the intent-to-treat analysis was a reduction in inflammatory papules and pustules. AzA 15% gel resulted in a 70% to 71% median reduction of facial papules and pustules compared with a 77% reduction with benzoyl peroxide 5% gel and a 63% reduction with clindamycin. AzA 15% gel was well-tolerated. In addition, a 1-year European observational study conducted by dermatologists in private practice evaluated the safety and efficacy of AzA 15% gel used as monotherapy or in combination with other agents in more than 1200 patients with acne. Most physicians (81.9%) described an improvement in patients' symptoms after an average of 34.6 days, and 93.9% of physicians reported patient improvement after an average of 73.1 days. Both physicians and patients assessed AzA 15% gel to be effective with 74% of patients being "very satisfied" at the end of therapy. AzA 15% gel was considered "well-tolerated" or "very well-tolerated" by 95.7% of patients. The majority of patients were more satisfied with AzA than with previous therapies. AzA 15% gel represents a new therapeutic option for the treatment of acne vulgaris.

  17. Desferrioxamine as an electron donor. Inhibition of membranal lipid peroxidation initiated by H2O2-activated metmyoglobin and other peroxidizing systems.

    PubMed

    Kanner, J; Harel, S

    1987-01-01

    Desferrioxamine (DFO) involvement in several peroxidative systems was studied. These systems included: a) membranal lipid peroxidation initiated by H2O2-activated metmyoglobin (or methemoglobin); b) phenol-red oxidation by activated metmyoglobin or horseradish peroxidase (HRP): c) beta-carotene-linoleate couple oxidation stimulated by lipoxygenase or hemin. Desferrioxamine was found to inhibit all these systems but not ferrioxamine (FO). Phenol-red oxidation by H2O2-horseradish peroxidase was inhibited competitively with DFO. Kinetic studies using the spectra changes in the Soret region of metmyoglobin suggest a mechanism by which H2O2 reacts with the iron-heme to form an intermediate of oxy-ferryl myoglobin that subsequently reacts with DFO to return the activated compound to the resting state. These activities of DFO resemble the reaction of other electron donors.

  18. Efficacy of hydrogen-peroxide-based mouthwash in altering enamel color.

    PubMed

    Jaime, Ivone Maria de Lima; França, Fabiana Mantovani Gomes; Basting, Roberta Tarkany; Turssi, Cecilia Pedroso; Amaral, Flávia Lucisano Botelho

    2014-02-01

    To analyze the efficacy of Colgate Plax Whitening mouthwash containing 1.5% hydrogen peroxide. 30 enamel fragments, obtained from the proximal surfaces of human third molars were darkened with Orange II methyl orange. The fragments were divided into three groups according to the type of bleaching agent applied (n = 10): (1) 10% carbamide peroxide gel (positive control, PC) was applied for 2 hours/day for 28 days; (2) a solution containing 1.5% hydrogen peroxide (Plax) was applied for 4 minutes once a day for 28 days, and (3) no bleaching agent, kept in artificial saliva (negative control, AS). The specimens were kept in artificial saliva between treatment intervals. The specimens were photographed before darkening (baseline), after darkening and before lightening and on the 28th day of whitening. Afterwards, they were analyzed with color measurement software using the CIELab system. The data for the L*, a* and b* parameters were submitted to two-way ANOVA with repeated measures. The values of deltaL *, deltaa *, deltab * and deltaE* were calculated using two procedures: (1) darkened versus original, and (2) bleached versus darkened. This data was submitted to the one-way ANOVA test. Multiple comparisons were conducted using the Tukey test (alpha = 0.05). When the specimens were subjected to bleaching agents, there was a significant increase in the brightness (L* parameter) of the enamel exposed to the gel and also to the bleaching solution. However, higher brightness was observed for the PC (gel) group. As for the axis a* parameters, there were no significant differences between the bleaching products. Regarding the axis b* parameters, the PC group underwent major changes (indicating a color change toward blue chroma), statistically greater than those of the Plax group. After bleaching, there was a significantly greater color change (deltaE*) in the PC group. Although the Plax solution caused a color change, it was less than that produced by the gel. The slightest

  19. Synthesis and Characterization of Ru(II) Tris(1,1O-phenanthroline)-Electron Acceptor Dyads Incorporating the 4-benzoyl-N-methylpyridinium Cation or N-Benzyl-N'-methyl-viologen. Improving the Dynamic Range, Sensitivity and Response Time of Sol-Gel Based Optical Oxygen Sensors

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Rawashdeh, Abdel-Monen M.; Elder, Ian A.; Yang, Jinhua; Dass, Amala; Sotiriou-Leventis, Chariklia

    2004-01-01

    The title compounds (1 and 2, above) were synthesized by Sonogashira coupling reactions of appropriate Ru(1I) complexes with the electron a cceptors. Characterization was conducted in solution and in frozen ma trices. Finally, the title compounds were evaluated as dopants of sol-gel materials. It was found that the intramolecular quenching efficie ncy of 4-benzoyl-Nmethylpyridinium cation in solution depends on the solvent: photoluminescence is quenched completely in CH,CN, but not i n methanol or ethanol. On the other hand, intramolecular emission que nching by 4-benzyl-N-methyl viologen is complete in all solvents. The difference between the two quenchers is traced electrochemically to t he solvation of the 4-benzoyl-Nmethylpyridiniums by alcohol. In froze n matrices or adsorbed on the surfaces of silica aerogel, both Ru(I1) complex/electron acceptor dyads of this study are photoluminescent, and the absence of quenching has been traced to the environmental rigi dity. When doped aerogels are cooled at 77 K, the emission intensity increases by approximately 4x, and the spectra shift to the blue, analogous to what is observed with Ru(I1) complexes in solutions undergoi ng fluid-to-rigid transition. However, in contrast to frozen solution s, the luminescent moieties in the bulk of aerogels kept at low tempe ratures are still accessible to gas-phase quenchers diffusing through the mesopores, leading to more sensitive platforms for sensors than o ther room-temperature configurations. Thus the photoluminescence of o ur Ru(I1) complex dyads adsorbed on aerogel is quenchable by O2 both at room temperature and at 77 K. Furthermore, it was also found that O 2 modulates the photoluminescence of aerogels doped with 4-benzoyl -N -methylpyridinium-based dyads over a wider dynamic range compared wi th aerogels doped with either our vislogen-based dyads or with Ru(I1) tris(1,lO-phenanthroline) itself.

  20. Mechanisms of haptoglobin protection against hemoglobin peroxidation triggered endothelial damage.

    PubMed

    Schaer, C A; Deuel, J W; Bittermann, A G; Rubio, I G; Schoedon, G; Spahn, D R; Wepf, R A; Vallelian, F; Schaer, D J

    2013-11-01

    Extracellular hemoglobin (Hb) has been recognized as a disease trigger in hemolytic conditions such as sickle cell disease, malaria, and blood transfusion. In vivo, many of the adverse effects of free Hb can be attenuated by the Hb scavenger acute-phase protein haptoglobin (Hp). The primary physiologic disturbances that can be caused by free Hb are found within the cardiovascular system and Hb-triggered oxidative toxicity toward the endothelium has been promoted as a potential mechanism. The molecular mechanisms of this toxicity as well as of the protective activities of Hp are not yet clear. Within this study, we systematically investigated the structural, biochemical, and cell biologic nature of Hb toxicity in an endothelial cell system under peroxidative stress. We identified two principal mechanisms of oxidative Hb toxicity that are mediated by globin degradation products and by modified lipoprotein species, respectively. The two damage pathways trigger diverse and discriminative inflammatory and cytotoxic responses. Hp provides structural stabilization of Hb and shields Hb's oxidative reactions with lipoproteins, providing dramatic protection against both pathways of toxicity. By these mechanisms, Hp shifts Hb's destructive pseudo-peroxidative reaction to a potential anti-oxidative function during peroxidative stress.

  1. The effect of iodine on the peroxidation of carbonyl compounds.

    PubMed

    Zmitek, Katja; Zupan, Marko; Stavber, Stojan; Iskra, Jernej

    2007-08-17

    Peroxidation of ketones and aldehydes with iodine as a catalyst was studied. Ketones reacted with 30% aq hydrogen peroxide in the presence of 10 mol % of iodine to yield gem-dihydroperoxides in acetonitrile and hydroperoxyketals in methanol. The yield of hydroperoxidation of various cyclic ketones was 60-98%, including androstane-3,17-dione, while acyclic ketones were converted with a similar efficiency. Aromatic aldehydes were also converted to gem-dihydroperoxides with hydrogen peroxide and iodine as catalyst in acetonitrile and to hydroperoxyacetal in methanol, while the reactivity of aliphatic ones remained the same as in noncatalyzed reactions. tert-Butylhydroperoxide reacted in a similar manner, giving the corresponding perether derivatives. A study was also made of the relative kinetics of dihydroperoxidation from which the Hammet equation gave a reaction constant (rho) of -2.76, indicating the strong positive charge development in the transition state and the important role of rehybridization in the conversion of hydroperoxyhemiketal to gem-dihydroperoxide. In acetonitrile, the iodine catalyst is apparently able to discriminate between the elimination of a hydroxy, methoxy, and hydroperoxy group and addition of water, methanol, and H2O2 to a carbonyl group.

  2. Synthesis, characterization and molecular modeling of some transition metal complexes of Schiff base derived from 5-aminouracil and 2-benzoyl pyridine

    NASA Astrophysics Data System (ADS)

    Abdel-Monem, Yasser K.; Abouel-Enein, Saeyda A.; El-Seady, Safa M.

    2018-01-01

    Multidentate Schiff base (H2L) ligand results from condensation of 5-aminouracil and 2-benzoyl pyridine and its metal chloride (Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Fe(III), Cr(III), Ru(III), Zr(IV) and Hf(IV)) complexes were prepared. The structural features of the ligand and its metal complexes were confirmed by elemental analyses, spectroscopic methods (IR, UV-Vis, 1H NMR, mass), magnetic moment measurements and thermal studies. The data refer to the ligand coordinates with metal ions in a neutral form and shows different modes of chelation toward the metal atom. All complexes have octahedral skeleton structure, tetrahedrally Mn(II), Ni(II), trigonalbipyramidal Co(II) and square planner Pd(II). Thermal decomposition of complexes as well as the interaction of different types of solvent of crystallization are assigned by thermogravimetric analysis. Molecular modeling of prepared complexes were investigated to study the expected anticancer activities of the prepared complexes. All metal complexes have no interaction except the complexes of Pd(II), Fe(III) and Mn(II).

  3. Glutamine Deprivation Causes Hydrogen Peroxide-induced Interleukin-8 Expression via Jak1/Stat3 Activation in Gastric Epithelial AGS Cells

    PubMed Central

    Lee, Yun Mi; Kim, Mi Jung; Kim, Youngha; Kim, Hyeyoung

    2015-01-01

    Background: The Janus kinase (Jak)/Signal transducers of activated transcription (Stat) pathway is an upstream signaling pathway for NF-κB activation in Helicobacter pylori-induced interleukin (IL)-8 production in gastric epithelial AGS cells. H. pylori activates NADPH oxidase and produces hydrogen peroxide, which activates Jak1/Stat3 in AGS cells. Therefore, hydrogen peroxide may be critical for IL-8 production via Jak/Stat activation in gastric epithelial cells. Glutamine is depleted during severe injury and stress and contributes to the formation of glutathione (GSH), which is involved in conversion of hydrogen peroxide into water as a cofactor for GSH peroxidase. Methods: We investigated whether glutamine deprivation induces hydrogen peroxide-mediated IL-8 production and whether hydrogen peroxide activates Jak1/Stat3 to induce IL-8 in AGS cells. Cells were cultured in the presence or absence of glutamine or hydrogen peroxide, with or without GSH or a the Jak/Stat specific inhibitor AG490. Results: Glutamine deprivation decreased GSH levels, but increased levels of hydrogen peroxide and IL-8, an effect that was inhibited by treatment with GSH. Hydrogen peroxide induced the activation of Jak1/Stat3 time-dependently. AG490 suppressed hydrogen peroxide- induced activation of Jak1/Stat3 and IL-8 expression in AGS cells, but did not affect levels of reactive oxygen species in AGS cells. Conclusions: In gastric epithelial AGS cells, glutamine deprivation increases hydrogen peroxide levels and IL-8 expression, which may be mediated by Jak1/Stat3 activation. Glutamine supplementation may be beneficial for preventing gastric inflammation by suppressing hydrogen peroxide-mediated Jak1/Stat3 activation and therefore, reducing IL-8 production. Scavenging hydrogen peroxide or targeting Jak1/Stat3 may also prevent oxidant-mediated gastric inflammation. PMID:26473156

  4. A reaction-diffusion model of cytosolic hydrogen peroxide.

    PubMed

    Lim, Joseph B; Langford, Troy F; Huang, Beijing K; Deen, William M; Sikes, Hadley D

    2016-01-01

    As a signaling molecule in mammalian cells, hydrogen peroxide (H2O2) determines the thiol/disulfide oxidation state of several key proteins in the cytosol. Localization is a key concept in redox signaling; the concentrations of signaling molecules within the cell are expected to vary in time and in space in manner that is essential for function. However, as a simplification, all theoretical studies of intracellular hydrogen peroxide and many experimental studies to date have treated the cytosol as a well-mixed compartment. In this work, we incorporate our previously reported reduced kinetic model of the network of reactions that metabolize hydrogen peroxide in the cytosol into a model that explicitly treats diffusion along with reaction. We modeled a bolus addition experiment, solved the model analytically, and used the resulting equations to quantify the spatiotemporal variations in intracellular H2O2 that result from this kind of perturbation to the extracellular H2O2 concentration. We predict that micromolar bolus additions of H2O2 to suspensions of HeLa cells (0.8 × 10(9)cells/l) result in increases in the intracellular concentration that are localized near the membrane. These findings challenge the assumption that intracellular concentrations of H2O2 are increased uniformly throughout the cell during bolus addition experiments and provide a theoretical basis for differing phenotypic responses of cells to intracellular versus extracellular perturbations to H2O2 levels. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Monolithic Hydrogen Peroxide Catalyst Bed Development

    NASA Technical Reports Server (NTRS)

    Ponzo, J. B.

    2003-01-01

    With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

  6. Hydrogen peroxide sensing using ultrathin platinum-coated gold nanoparticles with core@shell structure.

    PubMed

    Li, Yongxin; Lu, Qiufang; Wu, Shengnan; Wang, Lun; Shi, Xianming

    2013-03-15

    Ultrathin platinum-coated gold (Pt@Au) nanoparticles with core@shell structure have been developed by under-potential deposition (UPD) redox replacement technique. A single UPD Cu replacement with Pt(2+) produced a uniform Pt monolayer on the surface of gold nanoparticles, which are immobilized on glassy carbon electrode (GCE) surface based on electrostatic interaction. The ultrathin Pt@Au nanoparticles were confirmed by cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). Voltammetry and amperometric methodologies were used to evaluate the electrocatalytic activity of the Pt@Au nanoparticles modified electrode towards the reduction of hydrogen peroxide under the physiological condition. The present results show that ultrathin Pt coating greatly enhances the electrocatalytic activity towards the reduction of hydrogen peroxide, which can be utilized to fabricate the hydrogen peroxide sensor. Chronoamperometric experiments showed that at an applied potential of 0.08 V (vs. Ag/AgCl), the current reduction of hydrogen peroxide was linear to its concentration in the range of 1-450 μΜ, and the detection limit was found to be 0.18 μM (signal-to-noise ratio, S/N=3). Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Ozonation and alkaline-peroxide pretreatment of wheat straw for Cryptococcus curvatus fermentation

    NASA Technical Reports Server (NTRS)

    Greenwalt, C. J.; Hunter, J. B.; Lin, S.; McKenzie, S.; Denvir, A.

    2000-01-01

    Crop residues in an Advanced Life Support System (ALS) contain many valuable components that could be recovered and used. Wheat is 60% inedible, with approximately 90% of the total sugars in the residue cellulose and hemicellulose. To release these sugars requires pretreatment followed by enzymatic hydrolysis. Cryptococcus curvatus, an oleaginous yeast, uses the sugars in cellulose and hemicellulose for growth and production of storage triglycerides. In this investigation, alkaline-peroxide and ozonation pretreatment methods were compared for their efficiency to release glucose and xylose to be used in the cultivation of C. curvatus. Leaching the biomass with water at 65 degrees C for 4 h prior to pretreatment facilitated saccharification. Alkaline-peroxide and ozone pretreatment were almost 100% and 80% saccharification efficient, respectively. The sugars derived from the hydrolysis of alkaline-peroxide-treated wheat straw supported the growth of C. curvatus and the production of edible single-cell oil.

  8. Hydrogen peroxide-dependent antibacterial action of Melilotus albus honey.

    PubMed

    Sowa, P; Grabek-Lejko, D; Wesołowska, M; Swacha, S; Dżugan, M

    2017-07-01

    Honey originating from different floral sources exhibits the broad spectrum of antibacterial activity as a result of the presence of hydrogen peroxide as well as nonperoxide bioactive compounds. The mechanisms of antibacterial activity of Polish melilot honey were investigated for the first time. Polish melilot honey samples (Melilotus albus biennial = 3 and annual = 5, Melilotus officinalis = 1) were collected directly from beekeepers and analysed for pollen profile, basic physicochemical parameters, antioxidant capacity, radical scavenging activity, total phenolic contents as well as antibacterial properties against pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella spp. The physicochemical properties of melilot honey were specific for light-coloured unifloral honey samples and were not dependent on its botanical and geographical origin (P > 0·05). All tested honey samples exhibited inhibitory activity (above 90%) against Gram-positive bacteria at the concentration of 12·5-25%. Above 30-50% of antibacterial activity of melilot honey was connected with glucose oxidase enzyme action and was destroyed in the presence of catalase. Hydrogen peroxide-dependent antibacterial activity of honey was inversely correlated with its radical scavenging activity (r = -0·67) and phenolic compounds (r = -0·61). Antibacterial action of melilot honey depends not only on hydrogen peroxide produced by glucose oxidase, but also on other nonperoxide bioactive components of honey. Melilot honey is used in traditional medicine as an anticoagulant agent due to the possibility of the presence of the coumarin compounds which are specific for Melilotus plant. Melilotus albus is rarely used to produce honey, and antibacterial properties of this variety of honey had not been studied yet. Nine samples of melilot honey produced in different regions of Poland were analysed according to their antibacterial activity which was correlated

  9. A novel procedure to assess the non-enzymatic hydrogen-peroxide antioxidant capacity of metabolites with high UV absorption.

    PubMed

    Csepregi, Kristóf; Hideg, Éva

    2016-12-01

    Assays assessing non-enzymatic hydrogen peroxide antioxidant capacities are often hampered by the high UV absorption of the sample itself. This is a typical problem in studies using plant extracts with high polyphenol content. Our assay is based on comparing the 405 nm absorption of the product of potassium iodine and hydrogen peroxide in the presence and absence of a putative hydrogen peroxide reactive antioxidant. This method is free of interference with either hydrogen peroxide or antioxidant self-absorption and it is also suitable for high-throughput plate reader applications.

  10. Plasma lipid peroxidation and erythrocyte antioxidant enzymes status in workers exposed to cadmium.

    PubMed

    Babu, Kalahasthi Ravi; Rajmohan, Hirehal Raghavendra Rao; Rajan, Bagalur Krishna Murthy; Kumar, Karuna M

    2006-09-01

    Cadmium (Cd) is a corrosion-resistant metal, used extensively for electroplating in the automobile, electronic and aerospace industry. Only a few studies are available regarding Cd-induced oxidative stress in animals, but no reports are available regarding the effects of Cd on oxidative stress during occupational exposure. The present study was carried out to determine the plasma lipid peroxidation and erythrocyte antioxidant enzymes status in workers exposed to Cd during electroplating. 50 subjects exposed to Cd during electroplating formed the study group. An equal number of age-sex matched subjects, working in the administrative section, formed the control group. Urinary Cd levels were determined using the flameless atomic absorption spectrophotometer. Plasma lipid peroxidation and erythrocyte antioxidant enzymes were determined using spectrophotometric methods. A significant increase of plasma lipid peroxidation and a significant decrease of superoxide dismutase and glutathione peroxidase levels were noted in the study group compared with the control group. The level of plasma lipid peroxidation was positively and erythrocyte antioxidant enzymes were negatively and significantly associated with Cd levels in urine. Multiple regression analysis assessed the oxidative stress associated with Cd and other lifestyle confounding factors, such as age, body mass index, the consumption of vegetables, coffee, tea, smoking and alcohol. Analysis showed that the lifestyle confounding factors viz; smoking, body mass index and urinary Cd levels > 5 microg/g of creatinine, were significantly associated with oxidative stress. The results of the present study suggest that increased plasma lipid peroxidation and decreased superoxide dismutase levels could be used as biomarkers of oxidative stress in cadmium-exposed workers.

  11. Free standing graphene oxide film for hydrogen peroxide sensing

    NASA Astrophysics Data System (ADS)

    Ranjan, Pranay; Balakrishnan, Jayakumar; Thakur, Ajay D.

    2018-05-01

    We report hydrogen peroxide (H2O2)sensing using free standing graphene oxide thin films prepared using a cost effective scalable approach. Such sensors may find application in pharmaceutical and food processing industries.

  12. Effects of Vaporized Decontamination Systems on Selected Building Interior Materials: Vaporized Hydrogen Peroxide

    DTIC Science & Technology

    2009-01-01

    surfaces in buildings following a terrorist attack using CB agents. Vaporized hydrogen peroxide ( VHP ) and Cl02 are decontamination technologies that...decontaminant. The focus of this technical report is the evaluation of the building interior materials and the Steris VHP technology. 15. SUBJECT...TERMS Material Compatibility VHP vaporized hydrogen peroxide 16. SECURITY CLASSIFICATION OF: a. REPORT U b. ABSTRACT U c. THIS PAGE U 17

  13. Enhancing activated-peroxide formulations for porous materials: Test methods and results

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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 decontaminantmore » 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.« less

  14. Simultaneous removal of nitrate, hydrogen peroxide and phosphate in semiconductor acidic wastewater by zero-valent iron.

    PubMed

    Yoshino, Hiroyuki; Tokumura, Masahiro; Kawase, Yoshinori

    2014-01-01

    The zero-valent iron (ZVI) wastewater treatment has been applied to simultaneous removal of nitrate, hydrogen peroxide and phosphate in semiconductor acidic wastewaters. The simultaneous removal occurs by the reactions performed due to the sequential transformation of ZVI under the acidic condition. Fortunately the solution pH of semiconductor acidic wastewaters is low which is effective for the sequential transformation of ZVI. Firstly the reduction of nitrate is taken place by electrons generated by the corrosion of ZVI under acidic conditions. Secondly the ferrous ion generated by the corrosion of ZVI reacts with hydrogen peroxide and generates ·OH radical (Fenton reaction). The Fenton reaction consists of the degradation of hydrogen peroxide and the generation of ferric ion. Finally phosphate precipitates out with iron ions. In the simultaneous removal process, 1.6 mM nitrate, 9.0 mM hydrogen peroxide and 1.0 mM phosphate were completely removed by ZVI within 100, 15 and 15 min, respectively. The synergy among the reactions for the removal of nitrate, hydrogen peroxide and phosphate was found. In the individual pollutant removal experiment, the removal of phosphate by ZVI was limited to 80% after 300 min. Its removal rate was considerably improved in the presence of hydrogen peroxide and the complete removal of phosphate was achieved after 15 min.

  15. Oxygen venous embolism after the use of hydrogen peroxide during lumbar discectomy.

    PubMed

    Despond, O; Fiset, P

    1997-04-01

    The knee-prone position is commonly used for patients undergoing spinal surgery. Venous air embolism in such a position may be produced by the negative venous pressure gradient between the ambient air and the venous plexuses of the spinous process. When hydrogen peroxide is used to cleanse the wound, oxygen is produced. We report a case of suspected oxygen venous embolism during lumbar discectomy in the knee-prone position after use of H2O2. Immediately after irrigation of a discectomy wound with H2O2, a dramatic decrease of the PETCO2, blood pressure and oxygen saturation coincident with ST segment elevation occurred suggesting a coronary gas embolism. Symptomatic treatment was initiated immediately and the patient recovered without any sequelae. Although hydrogen peroxide has an innocuous reputation, cases of accidental ingestion or massive gas embolism after wound irrigation leading to death have been reported. A review of the literature suggests that many of the clinical and physiopathological features of air and oxygen emboli are similar. For both, measures of prevention and treatment of complications are similar. We argue that the use of hydrogen peroxide should be avoided during procedures where the position of the patient (sitting, knee-prone) increases the risk of gas embolism and that hydrogen peroxide is a potentially dangerous solution.

  16. Fiber post etching with hydrogen peroxide: effect of concentration and application time.

    PubMed

    de Sousa Menezes, Murilo; Queiroz, Ellyne Cavalcanti; Soares, Paulo Vinícius; Faria-e-Silva, André Luis; Soares, Carlos José; Martins, Luis Roberto Marcondes

    2011-03-01

    Etching is necessary to expose the fibers and enable both mechanical and chemical bonding of the resin core to the fiber post. This study evaluated the effect of concentration and application time of hydrogen peroxide on the surface topography and bond strength of glass fiber posts to resin cores. Fiber posts were etched with 24% or 50% hydrogen peroxide for 1, 5, or 10 min (n = 10). Posts without any treatment were used as a control. After etching, the posts were silanated and adhesive resin was applied. The posts were positioned into a mold to allow a self-cured resin core to be inserted. The post/resin assembly was serially sectioned into five beams that were subjected to a tensile bond strength test. Data were subjected to two-way ANOVA and Tukey test (α = 0.05). The surface topography was analyzed using scanning electronic microscopy. Non-etched post presents a relatively smooth surface without fiber exposure. Application of hydrogen peroxide increased the surface roughness and exposed the fibers. All experimental conditions yielded similar bond strength values that were higher than those obtained in the control group. Both 24% and 50% hydrogen peroxide exposure increased the bond strength of resin to the posts, irrespective of the application time. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. Hydroxy acetone and lactic acid synthesis from aqueous propylene glycol/hydrogen peroxide catalysis on Pd-black

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Disselkamp, Robert S.; Harris, Benjamin D.; Hart, Todd R.

    2008-07-20

    The production of polyol chemicals is of increasing interest as they are obtained from the catalytic processing of biological feedstock materials, which also is becoming more prevalent. A case in point is glycerol production, formed as a byproduct in biodiesel catalytic processing. Here we report the reaction of a simple 1,2-diol, propylene glycol, with hydrogen peroxide and a Pd-black catalyst under reflux conditions at 368 K. The experiments were performed by either co-addition of hydrogen peroxide with air sparging, or addition of hydrogen peroxide alone, each yielding hydroxy acetone (HA) and acetic acid (AA) products, with a lesser amount ofmore » lactic acid (LA) formed. Product conversion data at near neutral pH versus hydrogen peroxide equivalents added relative to substrate is presented. Hydrogen peroxide addition without air sparging at 5 equivalents resulted in 65% conversion with an HA:AA molar ratio of 2:1. Conversely, hydrogen peroxide addition with air sparging at only 0.75 equivalents resulted in 40% conversion with an HA:AA ratio of 3:1. From this it is concluded that although the product distribution in these chemistries is somewhat unchanged by air sparging, it is surprising that the amount of reactive oxygen is greatly enhanced with co-addition of O2/H2O2. Additional studies have revealed the amount of LA formed can be enhanced under acidic conditions (pH=1.5 compared to pH=8.5), such that 26% of total product formation is LA. Since hydrogen peroxide is an environmentally clean reagent and becoming more cost effective to use, this work may guide future applied investigations into polyol chemical syntheses.« less

  18. Effect of hydrogen peroxide on antibacterial activities of Canadian honeys.

    PubMed

    Brudzynski, Katrina

    2006-12-01

    Honey is recognized as an efficacious topical antimicrobial agent in the treatment of burns and wounds. The antimicrobial activity in some honeys depends on the endogenous hydrogen peroxide content. This study was aimed to determine whether honey's hydrogen peroxide level could serve as a honey-specific, activity-associated biomarker that would allow predicting and assessing the therapeutic effects of honey. Using a broth microdilution assay, I analyzed antibacterial activities of 42 Canadian honeys against two bacterial strains: Escherichia coli (ATCC 14948) and Bacillus subtilis (ATCC 6633). The MIC90 and MIC50 were established from the dose-response relationship between antibacterial activities and honey concentrations. The impact of H2O2 on antibacterial activity was determined (i) by measuring the levels of H2O2 before and after its removal by catalase and (ii) by correlating the results with levels of antibacterial activities. Canadian honeys demonstrated moderate to high antibacterial activity against both bacterial species. Both MIC90 and MIC50 revealed that the honeys exhibited a selective growth inhibitory activity against E. coli, and this activity was strongly influenced by endogenous H2O2 concentrations. Bacillus subtilis activity was marginally significantly correlated with H2O2 content. The removal of H2O2 by catalase reduced the honeys' antibacterial activity, but the enzyme was unable to completely decompose endogenous H2O2. The 25%-30% H2O2 "leftover" was significantly correlated with the honeys' residual antibacterial activity against E. coli. These data indicate that all Canadian honeys exhibited antibacterial activity, with higher selectivity against E. coli than B. subtilis, and that these antibacterial activities were correlated with hydrogen peroxide production in honeys. Hydrogen peroxide levels in honey, therefore, is a strong predictor of the honey's antibacterial activity.

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

    PubMed

    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.

  20. Nonthermal dielectric-barrier discharge plasma-induced inactivation involves oxidative DNA damage and membrane lipid peroxidation in Escherichia coli.

    PubMed

    Joshi, Suresh G; Cooper, Moogega; Yost, Adam; Paff, Michelle; Ercan, Utku K; Fridman, Gregory; Friedman, Gary; Fridman, Alexander; Brooks, Ari D

    2011-03-01

    Oxidative stress leads to membrane lipid peroxidation, which yields products causing variable degrees of detrimental oxidative modifications in cells. Reactive oxygen species (ROS) are the key regulators in this process and induce lipid peroxidation in Escherichia coli. Application of nonthermal (cold) plasma is increasingly used for inactivation of surface contaminants. Recently, we reported a successful application of nonthermal plasma, using a floating-electrode dielectric-barrier discharge (FE-DBD) technique for rapid inactivation of bacterial contaminants in normal atmospheric air (S. G. Joshi et al., Am. J. Infect. Control 38:293-301, 2010). In the present report, we demonstrate that FE-DBD plasma-mediated inactivation involves membrane lipid peroxidation in E. coli. Dose-dependent ROS, such as singlet oxygen and hydrogen peroxide-like species generated during plasma-induced oxidative stress, were responsible for membrane lipid peroxidation, and ROS scavengers, such as α-tocopherol (vitamin E), were able to significantly inhibit the extent of lipid peroxidation and oxidative DNA damage. These findings indicate that this is a major mechanism involved in FE-DBD plasma-mediated inactivation of bacteria.

  1. Nonthermal Dielectric-Barrier Discharge Plasma-Induced Inactivation Involves Oxidative DNA Damage and Membrane Lipid Peroxidation in Escherichia coli▿

    PubMed Central

    Joshi, Suresh G.; Cooper, Moogega; Yost, Adam; Paff, Michelle; Ercan, Utku K.; Fridman, Gregory; Friedman, Gary; Fridman, Alexander; Brooks, Ari D.

    2011-01-01

    Oxidative stress leads to membrane lipid peroxidation, which yields products causing variable degrees of detrimental oxidative modifications in cells. Reactive oxygen species (ROS) are the key regulators in this process and induce lipid peroxidation in Escherichia coli. Application of nonthermal (cold) plasma is increasingly used for inactivation of surface contaminants. Recently, we reported a successful application of nonthermal plasma, using a floating-electrode dielectric-barrier discharge (FE-DBD) technique for rapid inactivation of bacterial contaminants in normal atmospheric air (S. G. Joshi et al., Am. J. Infect. Control 38:293-301, 2010). In the present report, we demonstrate that FE-DBD plasma-mediated inactivation involves membrane lipid peroxidation in E. coli. Dose-dependent ROS, such as singlet oxygen and hydrogen peroxide-like species generated during plasma-induced oxidative stress, were responsible for membrane lipid peroxidation, and ROS scavengers, such as α-tocopherol (vitamin E), were able to significantly inhibit the extent of lipid peroxidation and oxidative DNA damage. These findings indicate that this is a major mechanism involved in FE-DBD plasma-mediated inactivation of bacteria. PMID:21199923

  2. UVA Photoirradiation of Nitro-Polycyclic Aromatic Hydrocarbons—Induction of Reactive Oxygen Species and Formation of Lipid Peroxides

    PubMed Central

    Xia, Qingsu; Yin, Jun J.; Zhao, Yuewei; Wu, Yuh-Sen; Wang, Yu-Qui; Ma, Liang; Chen, Shoujun; Sun, Xin; Fu, Peter P.; Yu, Hongtao

    2013-01-01

    Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) are a class of genotoxic environmental contaminants. We have long been interested in determining the mechanisms by which nitro-PAHs induce genotoxicity. Although the metabolic activation of nitro-PAHs leading to toxicological activities has been well studied, the photo-induced activation of nitro-PAHs has seldom been reported. In this paper, we report photo-induced lipid peroxidation by 19 nitro-PAHs. The results indicated that all but two of the nitro-PAHs can induce lipid peroxidation. Mechanistic studies suggest that lipid peroxidation by nitro-PAHs is mediated by free radicals generated in the reaction. There was no structural correlation between the nitro-PAHs and their ability to induce lipid peroxidation upon UVA irradiation, or between the HOMO-LUMO gap and the ability to cause lipid peroxidation. Most of the nitro-PAHs are less potent in terms of causing lipid peroxidation than their parent PAHs. The lack of correlation is attributed to the complex photophysics and photochemistry of the nitro-PAHs and the yield of reactive oxygen species (ROS) and other factors. PMID:23493032

  3. Dual Ca2+ requirement for optimal lipid peroxidation of low density lipoprotein by activated human monocytes.

    PubMed

    Li, Q; Tallant, A; Cathcart, M K

    1993-04-01

    The oxidative modification of LDL seems a key event in atherogenesis and may participate in inflammatory tissue injury. Our previous studies suggested that the process of LDL oxidation by activated human monocytes/macrophages required O2- and activity of intracellular lipoxygenase. Herein, we studied the mechanisms involved in this oxidative modification of LDL. In this study, we used the human monocytoid cell line U937 to examine the role of Ca2+ in U937 cell-mediated lipid peroxidation of LDL. U937 cells were activated by opsonized zymosan. Removal of Ca2+ from cell culture medium by EGTA inhibited U937 cell-mediated peroxidation of LDL lipids. Therefore, Ca2+ influx and mobilization were examined for their influence on U937 cell-mediated LDL lipid peroxidation. Ca2+ channel blockers nifedipine and verapamil blocked both Ca2+ influx and LDL lipid peroxidation by activated U937 cells. The inhibitory effects of nifedipine and verapamil were dose dependent. TMB-8 and ryanodine, agents known to prevent Ca2+ release from intracellular stores, also caused a dose-dependent inhibition of LDL lipid peroxidation by activated U937 cells while exhibiting no effect on Ca2+ influx. Thus, both Ca2+ influx through functional calcium channels and Ca2+ mobilization from intracellular stores participate in the oxidative modification of LDL by activated U937 cells. 45Ca2+ uptake experiments revealed profound Ca2+ influx during the early stages of U937 cell activation, however, the Ca2+ ionophore 4-bromo A23187 was unable to induce activation of U937 cells and peroxidation of LDL lipids. Release of intracellular Ca2+ by thapsigargin only caused a suboptimal peroxidation of LDL lipids. Our results indicate that although increases in intracellular Ca2+ levels provided by both influx and intracellular Ca2+ mobilization are required, other intracellular signals may be involved for optimal peroxidation of LDL lipids by activated human monocytes.

  4. Hydrogen peroxide-induced apoptosis in human gingival fibroblasts

    PubMed Central

    Gutiérrez-Venegas, Gloria; Guadarrama-Solís, Adriana; Muñoz-Seca, Carmen; Arreguín-Cano, Juan Antonio

    2015-01-01

    In the process of bleaching vital, discolored teeth, low concentrations of hydrogen peroxide (H2O2) are effective alternatives to heat-activated 30% H2O2. However, interest has been expressed in the assessment of pathological effects of long-term exposure to bleaching agents such as irritation and ulceration of the gingival or other soft tissues. The aim of the present study was to determine the effect of hydrogen peroxide on apoptosis in human gingival fibroblasts (HGF). Cytochrome c, Bcl-2, Bax, Bid and caspase-3 protein expression were detected by Western blotting. HGF cell apoptosis induced by H2O2 was both dose and time dependent. The addition of H2O2 resulted in the release of cytochrome c to the cytosol, and an increase of Caspase-3 cleavage. Data suggest that oxidative stress-induced apoptosis in HGF is intrinsic pathway involved the release of apoptotic signal from mitochondria. PMID:26884825

  5. Sex-related differences in lipid peroxidation and photoprotection in Pistacia lentiscus.

    PubMed

    Juvany, Marta; Müller, Maren; Pintó-Marijuan, Marta; Munné-Bosch, Sergi

    2014-03-01

    Sex-related differences in the response of dioecious plants to abiotic stress have been poorly studied to date. This work explored to what extent sex may affect plant stress responses in Pistacia lentiscus L. (Anacardiaceae), a tree well adapted to Mediterranean climatic conditions. It was hypothesized that a greater reproductive effort in females may increase oxidative stress in leaves, particularly when plants are exposed to abiotic stress. Measurements of oxidative stress markers throughout the year revealed increased lipid peroxidation in females, but only during the winter. Enhanced lipid peroxidation in females was associated with reduced photoprotection, as indicated by reduced tocopherol levels and nonphotochemical quenching (NPQ) of chlorophyll fluorescence. Enhanced lipid peroxidation in females was also observed at predawn, which was associated with increased lipoxygenase activity and reduced cytokinin levels. An analysis of the differences between reproductive (R) and nonreproductive (NR) shoots showed an enhanced photoprotective capacity in R shoots compared to NR shoots in females. This capacity was characterized by an increased NPQ and a better antioxidant protection (increased carotenoid and tocopherol levels per unit of chlorophyll) in R compared to NR shoots. It is concluded that (i) females exhibit higher lipid peroxidation in leaves than males, but only during the winter (when sex-related differences in reproductive effort are the highest), (ii) this is associated with a lower photoprotective capacity at midday, as well as enhanced lipoxygenase activity and reduced cytokinin levels at predawn, and (iii) photoprotection capacity is higher in R relative to NR shoots in females.

  6. Sex-related differences in lipid peroxidation and photoprotection in Pistacia lentiscus

    PubMed Central

    Munné-Bosch, Sergi

    2014-01-01

    Sex-related differences in the response of dioecious plants to abiotic stress have been poorly studied to date. This work explored to what extent sex may affect plant stress responses in Pistacia lentiscus L. (Anacardiaceae), a tree well adapted to Mediterranean climatic conditions. It was hypothesized that a greater reproductive effort in females may increase oxidative stress in leaves, particularly when plants are exposed to abiotic stress. Measurements of oxidative stress markers throughout the year revealed increased lipid peroxidation in females, but only during the winter. Enhanced lipid peroxidation in females was associated with reduced photoprotection, as indicated by reduced tocopherol levels and nonphotochemical quenching (NPQ) of chlorophyll fluorescence. Enhanced lipid peroxidation in females was also observed at predawn, which was associated with increased lipoxygenase activity and reduced cytokinin levels. An analysis of the differences between reproductive (R) and nonreproductive (NR) shoots showed an enhanced photoprotective capacity in R shoots compared to NR shoots in females. This capacity was characterized by an increased NPQ and a better antioxidant protection (increased carotenoid and tocopherol levels per unit of chlorophyll) in R compared to NR shoots. It is concluded that (i) females exhibit higher lipid peroxidation in leaves than males, but only during the winter (when sex-related differences in reproductive effort are the highest), (ii) this is associated with a lower photoprotective capacity at midday, as well as enhanced lipoxygenase activity and reduced cytokinin levels at predawn, and (iii) photoprotection capacity is higher in R relative to NR shoots in females. PMID:24378602

  7. A high-throughput microtiter plate based method for the determination of peracetic acid and hydrogen peroxide.

    PubMed

    Putt, Karson S; Pugh, Randall B

    2013-01-01

    Peracetic acid is gaining usage in numerous industries who have found a myriad of uses for its antimicrobial activity. However, rapid high throughput quantitation methods for peracetic acid and hydrogen peroxide are lacking. Herein, we describe the development of a high-throughput microtiter plate based assay based upon the well known and trusted titration chemical reactions. The adaptation of these titration chemistries to rapid plate based absorbance methods for the sequential determination of hydrogen peroxide specifically and the total amount of peroxides present in solution are described. The results of these methods were compared to those of a standard titration and found to be in good agreement. Additionally, the utility of the developed method is demonstrated through the generation of degradation curves of both peracetic acid and hydrogen peroxide in a mixed solution.

  8. A High-Throughput Microtiter Plate Based Method for the Determination of Peracetic Acid and Hydrogen Peroxide

    PubMed Central

    Putt, Karson S.; Pugh, Randall B.

    2013-01-01

    Peracetic acid is gaining usage in numerous industries who have found a myriad of uses for its antimicrobial activity. However, rapid high throughput quantitation methods for peracetic acid and hydrogen peroxide are lacking. Herein, we describe the development of a high-throughput microtiter plate based assay based upon the well known and trusted titration chemical reactions. The adaptation of these titration chemistries to rapid plate based absorbance methods for the sequential determination of hydrogen peroxide specifically and the total amount of peroxides present in solution are described. The results of these methods were compared to those of a standard titration and found to be in good agreement. Additionally, the utility of the developed method is demonstrated through the generation of degradation curves of both peracetic acid and hydrogen peroxide in a mixed solution. PMID:24260173

  9. Peroxiredoxins: Guardians Against Oxidative Stress and Modulators of Peroxide Signaling

    PubMed Central

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

    2015-01-01

    Peroxiredoxins (Prxs) are a ubiquitous family of cysteine-dependent peroxidase enzymes that play dominant roles in regulating peroxide levels within cells. These enzymes, often present at high levels and capable of rapidly clearing peroxides, display a remarkable array of variations in their oligomeric states and susceptibility to regulation by hyperoxidative inactivation and other post-translational modifications. Key conserved residues within the active site promote catalysis by stabilizing the transition state required for transferring the terminal oxygen of hydroperoxides to the active site (peroxidatic) cysteine residue. Extensive investigations continue to expand our understanding of the scope of their importance as well as the structures and forces at play within these critical defense and regulatory enzymes. PMID:26067716

  10. Reversible cysteine oxidation in hydrogen peroxide sensing and signal transduction.

    PubMed

    García-Santamarina, Sarela; Boronat, Susanna; Hidalgo, Elena

    2014-04-29

    Activation of redox cascades through hydrogen peroxide-mediated reversible cysteine oxidation is a major mechanism for intracellular signaling. Understanding why some cysteine residues are specifically oxidized, in competition with other proximal cysteine residues and in the presence of strong redox buffers, is therefore crucial for understanding redox signaling. In this review, we explore the recent advances in thiol-redox chemistry linked to signaling. We describe the last findings in the field of redox sensors, those that are naturally present in different model organisms as well as those that have been engineered to quantify intracellular hydrogen peroxide concentrations. Finally, we provide a summary of the newest approaches developed to study reversible cysteine oxidation at the proteomic level.

  11. Catalytic and inhibiting effects of lithium peroxide and hydroxide on sodium chlorate decomposition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cannon, J.C.; Zhang, Y.

    1995-09-01

    Chemical oxygen generators based on sodium chlorate and lithium perchlorate are used in airplanes, submarines, diving, and mine rescue. Catalytic decomposition of sodium chlorate in the presence of cobalt oxide, lithium peroxide, and lithium hydroxide is studied using thermal gravimetric analysis. Lithium peroxide and hydroxide are both moderately active catalysts for the decomposition of sodium chlorate when used alone, and inhibitors when used with the more active catalyst cobalt oxide.

  12. Kinetics of the hydrolysis of N-benzoyl-l-serine methyl ester catalysed by bromelain and by papain. Analysis of modifier mechanisms by lattice nomography, computational methods of parameter evaluation for substrate-activated catalyses and consequences of postulated non-productive binding in bromelain- and papain-catalysed hydrolyses

    PubMed Central

    Wharton, Christopher W.; Cornish-Bowden, Athel; Brocklehurst, Keith; Crook, Eric M.

    1974-01-01

    1. N-Benzoyl-l-serine methyl ester was synthesized and evaluated as a substrate for bromelain (EC 3.4.22.4) and for papain (EC 3.4.22.2). 2. For the bromelain-catalysed hydrolysis at pH7.0, plots of [S0]/vi (initial substrate concn./initial velocity) versus [S0] are markedly curved, concave downwards. 3. Analysis by lattice nomography of a modifier kinetic mechanism in which the modifier is substrate reveals that concave-down [S0]/vi versus [S0] plots can arise when the ratio of the rate constants that characterize the breakdown of the binary (ES) and ternary (SES) complexes is either less than or greater than 1. In the latter case, there are severe restrictions on the values that may be taken by the ratio of the dissociation constants of the productive and non-productive binary complexes. 4. Concave-down [S0]/vi versus [S0] plots cannot arise from compulsory substrate activation. 5. Computational methods, based on function minimization, for determination of the apparent parameters that characterize a non-compulsory substrate-activated catalysis are described. 6. In an attempt to interpret the catalysis by bromelain of the hydrolysis of N-benzoyl-l-serine methyl ester in terms of substrate activation, the general substrate-activation model was simplified to one in which only one binary ES complex (that which gives rise directly to products) can form. 7. In terms of this model, the bromelain-catalysed hydrolysis of N-benzoyl-l-serine methyl ester at pH7.0, I=0.1 and 25°C is characterized by Km1 (the dissociation constant of ES)=1.22±0.73mm, k (the rate constant for the breakdown of ES to E+products, P)=1.57×10−2±0.32×10−2s−1, Ka2 (the dissociation constant that characterizes the breakdown of SES to ES and S)=0.38±0.06m, and k′ (the rate constant for the breakdown of SES to E+P+S)=0.45±0.04s−1. 8. These parameters are compared with those in the literature that characterize the bromelain-catalysed hydrolysis of α-N-benzoyl-l-arginine ethyl ester and

  13. [Indicators of lipid peroxidation in the blood in hereditary predisposition to arteriosclerosis].

    PubMed

    Davidenkova, E F; Shafran, M G; Veksler, B M

    1990-02-01

    In members of the families whose parents had atherosclerosis complicated by macrofocal myocardial infarction or stroke, the serum level of lipid peroxidation products was correlated to enzymatic activity of neutrophil and red blood cells oxidation-antioxidation. In persons with hereditary predisposition to atherosclerosis both with clinical signs of atherosclerosis and phenotypically healthy against the control group there was elevated content of plasma acylhydroperoxides and hypoactivity of neutrophil myeloperoxidase. Determination of lipid peroxidation products by malonic dealdehyde showed this parameter to be higher in members of the families of the study group and in those with cardiovascular disorders. For those whose parents had atherosclerosis versus control subjects there were no differences in the activity of superoxide dismutase, glutation peroxidase and catalase in the blood red cells. Shifts in lipid peroxidation and activity of blood myeloperoxidase are identical in type and may represent a pathogenetic ling in formation of hereditary predisposition to cardiovascular disorders of atherosclerotic origin, the detection of which becomes feasible in a subclinical period.

  14. Development of biological and nonbiological explanations for the Viking label release data. [hydrogen peroxide theory

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The plausibility that hydrogen peroxide, widely distributed within the Mars surface material, was responsible for the evocative response obtained by the Viking Labeled Release (LR) experiment on Mars was investigated. Although a mixture of gamma Fe2O3 and silica sand stimulated the LR nutrient reaction with hydrogen peroxide and reduced the rate of hydrogen decomposition under various storage conditions, the Mars analog soil prepared by the Viking Inorganic Analysis Team to match the Mars analytical data does not cause such effects. Nor is adequate resistance to UV irradiation shown. On the basis of the results and consideration presented while the hydrogen peroxide theory remains the most, if not only, attractive chemical explanation of the LR data, it remains unconvincing on critical points. Until problems concerning the formation and stabilization of hydrogen peroxide on the surface of Mars can be overcome, adhere to the scientific evidence requires serious consideration of the biological theory.

  15. Evaluation of the toxicity and efficacy of hydrogen peroxide treatments on eggs of warm and cool water fishes

    USGS Publications Warehouse

    Rach, J.J.; Gaikowski, M.P.; Howe, G.E.; Schreier, Theresa M.

    1998-01-01

    The use of hydrogen peroxide in aquaculture is growing and there is a need to develop fundamental guidelines to effectively treat diseased fish. The safety (toxicity) of hydrogen peroxide treatments was determined on eggs of representative warm- and coolwater fish species. Eggs of northern pike (Esox lucius), walleye (Stizostedion vitreum), yellow perch (Pel ca flavescens), white sucker (Catostomus commersoni), lake sturgeon (Acipenser fulvescens), paddlefish (Polyodon spathula), common carp (Cyprinus carpio), and channel catfish (Ictalurus punctatus) were cultured in egg jars or aquaria. Treatments were initiated with non-eyed eggs and continued until all viable eggs had hatched. Eggs were treated daily for 15 min Monday through Friday with either 0, 500, 1000, 3000, or 6000 mu l l(-1) of hydrogen peroxide. For all species, the mean percent hatch was greater in eggs treated with 1000 mu l l(-1) hydrogen peroxide for 15 min than in the untreated controls. Common carp, lake sturgeon, and paddlefish were the least sensitive to hydrogen peroxide with percent hatch ranging from 40 to 48% in the 6000 mu l l(-1) hydrogen peroxide treatment. Fungal infections reduced or eliminated the hatch in most controls whereas nearly all treated eggs remained free of infection; hydrogen peroxide inhibited fungal infections on fish eggs. (C) 1998 Elsevier Science B.V. All rights reserved.

  16. Synthesis, spectroscopic and structural characterization of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine with theoretical calculations using density functional theory.

    PubMed

    Inkaya, Ersin; Dinçer, Muharrem; Sahan, Emine; Yıldırım, Ismail

    2013-10-01

    In this paper, we will report a combined experimental and theoretical investigation of the molecular structure and spectroscopic parameters (FT-IR, (1)H NMR, (13)C NMR) of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine. The compound crystallizes in the triclinic space group P-1 with Z=2. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311G(d,p) and 6-311++G(d,p) basis sets in ground state and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential (ESP). Also, non-linear optical properties of the title compound were performed at B3LYP/6-311++G(d,p) level. The theoretical results showed an excellent agreement with the experimental values. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    PubMed

    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.

  18. Hydrogen peroxide biosensor based on a myoglobin/hydrophilic room temperature ionic liquid film.

    PubMed

    Safavi, Afsaneh; Farjami, Fatemeh

    2010-07-01

    The composite film based on Nafion and hydrophilic room temperature ionic liquid (RTIL) 1-butyl-3-methyl-imidazolium chloride ([bmim]Cl) was used as an immobilization matrix to entrap myoglobin (Mb). The study of ionic liquid (IL)-Mb interaction by ultraviolet-visible (UV-vis) spectroscopy showed that Mb retains its native conformation in the presence of IL. The immobilized Mb displayed a pair of well-defined cyclic voltammetric peaks with a formal potential (E(o)(')) of -0.35 V in a 0.1 M phosphate buffer solution (PBS) of pH 7.0. The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide, based on which a mediator-free amperometric biosensor for hydrogen peroxide was designed. The linear range for the determination of hydrogen peroxide was from 1.0 to 180 microM with a detection limit of 0.14 microM at a signal/noise ratio of 3. The apparent Michaelis constant (K(m)(app)) for the electrocatalytic reaction was 22.6 microM. The stability, repeatability, and selectivity of the sensor were evaluated. The proposed biosensor has a lower detection limit than many other IL-heme protein-based biosensors and is free from common interference in hydrogen peroxide biosensors. 2010 Elsevier Inc. All rights reserved.

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

    PubMed Central

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

    2015-01-01

    Abstract Spices are rich in natural antioxidants and have been shown to be potent inhibitors of lipid peroxidation during cooking of meat. Turmeric contains unique conjugated curcuminoids with strong antioxidant activity. Piperine, one of the main constituents of black pepper, is known to increase the bioavailability of curcuminoids in mouse and human studies when consumed with turmeric. We investigated whether adding black pepper to turmeric powder may further inhibit lipid peroxidation when 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. PMID:25582173

  20. Aesthetic Rehabilitation of Discoloured Nonvital Anterior tooth with Carbamide Peroxide Bleaching: Case Series

    PubMed Central

    Badole, Gautam P; Warhadpande, Manjusha M; Bahadure, Rakesh N; Badole, Shital G

    2013-01-01

    Discolouration of teeth, especially the anteriores, can result in considerably cosmetic impairment in person. Combine effects of intrinsic and extrinsic colour determines the appearance of teeth. Whitening of teeth with bleaching is a more conservative therapeutic method than full crowns, veneers or composite restorations which is more invasive and expensive. Among bleaching techniques, in office bleaching with carbamide peroxide provide superior aesthetic result in short period of time with no adverse effects. This paper presents case series of tooth discolouration in non-vital tooth which was successfully bleached using 35 % carbamide peroxide. After 1 year follow up the prognosis was good with no reversal of tooth discolouration. This case report allows the better understanding of the concept of nonvital tooth bleaching with carbamide peroxide which gives a non-invasive alternative for aesthetic purpose in preserving the natural tooth structure. PMID:24551731

  1. Self-assembly behavior of tail-to-tail superstructure formed by mono-6-O-(4-carbamoylmethoxy-benzoyl)-β-cyclodextrin in solution and the solid state.

    PubMed

    Xu, Zhe; Chen, Xin; Liu, Jing; Yan, Dong-Qing; Diao, Chun-Hua; Guo, Min-Jie; Fan, Zhi

    2014-07-01

    A novel mono-modified β-cyclodextrin (β-CD) consisting of 4-carbamoylmethoxy-benzoyl unit at the primary side was synthesized and its self-assembly behavior was determined by X-ray crystallography and NMR spectroscopy. The crystal structure shows a 'Yin-Yang'-like packing mode, in which the modified β-CD exhibits a channel superstructure formed by a tail-to-tail dimer as the repeating motif with the substituted group embedded within the hydrophobic cavity of the facing β-CD. The geometry of the substituted group is determined by the inclusion of the cavity and is further stabilized by two intermolecular hydrogen bonds between the carbonyl O atom and phenyl group. Furthermore, NMR ROESY investigation indicates that the self-assembly behavior of the substituted group within the β-CD cavity is retained in aqueous solution, and the effective binding constant Ka was calculated to be 1330 M(-1) by means of (1)H NMR titration according to iterative determination. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Catalase protection of neuronal survival in vitro is not directed to the accumulation of peroxides in the culture medium.

    PubMed

    Martin, E M; Skaper, S D; Varon, S

    1987-01-01

    Walicke et al. (1986, J. Neurosci. 6, 1114-1121) have shown that catalase can replace the pyruvate requirement for survival of CNS neurons cultured in vitro. Since presently the only known function of catalase is the enzymatic degradation of hydrogen peroxide to water and oxygen, the simplest interpretation of the ability of catalase to support neuronal survival would be that catalase removes from the culture medium hydrogen peroxide. To test this hypothesis 8-day embryonic chick forebrain cells were cultured for 24 hr in a modified Eagle's Basal Medium with the serum-free supplement N1 (HEBM/N1) in the presence or absence of Phenol Red, 20 micrograms/ml catalase, 1 mM pyruvate, and/or 25 mM N-2-hydroxyethylpiperazine-N'-2-ethane-sulfonic acid (HEPES) on a polyornithine-laminin substratum. The various media were then assayed for peroxide content using the potassium iodide method described by Wang and Nixon (1978, In Vitro 14, 714-722). The present data reveal that (1) HEBM/N1 normally contains approximately 50 microM peroxides, little of which is hydrogen peroxide, (2) the organic peroxide levels accumulating in this medium are not reduced by either catalase or pyruvate, and (3) medium modifications can reduce to no longer detectable levels the peroxides accumulating in the medium, but catalase or pyruvate is still required for neuronal survival. We conclude that catalase must exert its survival-promoting action at levels other than peroxides accumulating in the culture medium.

  3. The study of hydrogen peroxide level under cisplatin action using genetically encoded sensor hyper

    NASA Astrophysics Data System (ADS)

    Belova, A. S.; Orlova, A. G.; Maslennikova, A. V.; Brilkina, A. A.; Balalaeva, I. V.; Antonova, N. O.; Mishina, N. M.; Shakhova, N. M.; Belousov, V. V.

    2014-03-01

    The aim of the work was to study the participation of hydrogen peroxide in reaction of cervical cancer cell line HeLa Kyoto on cisplatin action. Determination of hydrogen peroxide level was performed using genetically encoded fluorescent sensor HyPer2. The dependence of cell viability on cisplatin concentration was determined using MTT assay. Mechanisms of cell death as well as HyPer2 reaction was revealed by flow cytometry after 6-hours of incubation with cisplatin in different concentrations. Cisplatin used in low concentrations had no effect on hydrogen peroxide level in HeLa Kyoto cells. Increase of HyPer2 fluorescence was detected only after exposure with cisplatin in high concentration. The reaction was not the consequence of cell death.

  4. A new amperometric nanostructured sensor for the analytical determination of hydrogen peroxide.

    PubMed

    Guascito, M R; Filippo, E; Malitesta, C; Manno, D; Serra, A; Turco, A

    2008-12-01

    A new amperometric, nanostructured sensor for the analytical determination of hydrogen peroxide is proposed. This sensor was constructed by immobilizing silver nanoparticles in a polyvinyl alcohol (PVA) film on a platinum electrode, which was performed by direct drop-casting silver nanoparticles that were capped in a PVA colloidal suspension. UV-vis spectroscopy, X-ray diffraction and transmission electron microscopy were used to give a complete characterization of the nanostructured film. Cyclic voltammetry experiments yielded evidence that silver nanoparticles facilitate hydrogen peroxide reduction, showing excellent catalytic activity. Moreover, the cronoamperometric response of modified sensors was dependent on nanoparticle lifetime. Experiments were performed, using freshly prepared solutions, after 4 and 8 days. Results concerning the quantitative analysis of hydrogen peroxide, in terms of detection limit, linear range, sensitivity and standard deviation (STD), are discussed for each tested sensor type. Utilization of two different linear ranges (40 microM to 6mM and 1.25 microM to 1.0mM) enabled the assessment of concentration intervals having up to three orders of magnitude. Moreover, the electrode made using a 4-day-old solution showed the maximal sensitivity of 128 nA microM(-1)(4090 nA microM(-1)cm(-2)), yielding a limit of detection of 1 microuM and STD of 2.5 microAmM(-1). All of these analytical parameters make the constructed sensors suitable for peroxide determination in aqueous solution.

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

    PubMed

    Xia, Zhenqiang; Wu, Shengjun; Chen, Jinhua

    2013-08-01

    Chitosan is not soluble in water, which limits its wide application particularly in the medicine and food industry. In the present study, water soluble chitosan (WSC) was prepared by hydrolyzing chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid in homogeneous phase. Factors affecting hydrolysis were investigated and the optimal hydrolysis conditions were determined. The WSC structure was characterized by Fourier transform infrared spectroscopy. The resulting products were composed of chitooligosaccharides of DP 2-9. The WSC content of the product and the yield were 94.7% and 92.3% (w/w), respectively. The results indicate that WSC can be effectively prepared by hydrolysis of chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Endogenous Intoxication and Saliva Lipid Peroxidation in Patients with Lung Cancer.

    PubMed

    Bel'skaya, Lyudmila V; Kosenok, Victor K; Massard, Gilbert

    2016-11-16

    This research was aimed at a search for regularities in changes to parameters of endogenous intoxication and saliva lipid peroxidation in patients with lung cancer, non-malignant lung diseases, and apparently healthy people. All patients went through saliva sampling at an amount of 1 mL. A concentration of malondialdehyde (MDA) was measured according to a reaction with thiobarbituric acid, and a level of middle molecules (MM) was measured with UV spectroscopy at 254 and 280 nm, while the content of lipid peroxidation products was measured according to a degree of heptane extract light absorption at wavelengths of 220, 232, 278, and 400 nm. It has been revealed that in the context of lung cancer, the level of diene conjugates decreases, increasing the level of triene conjugates, Schiff's bases, and MM. As a tumor grows, there is a decrease in the level of lipid peroxidation primary products and an increase in endotoxemia phenomena. The process is more apparent when going from local to locally advanced disease states. The nature of the MDA change is nonlinearly associated with tumor progression. The findings might be used to optimize traditional aids of diagnostics, in disease state forecasting, in treatment monitoring, etc.

  7. Erythrocyte membrane stability to hydrogen peroxide is decreased in Alzheimer disease.

    PubMed

    Gilca, Marilena; Lixandru, Daniela; Gaman, Laura; Vîrgolici, Bogdana; Atanasiu, Valeriu; Stoian, Irina

    2014-01-01

    The brain and erythrocytes have similar susceptibility toward free radicals. Therefore, erythrocyte abnormalities might indicate the progression of the oxidative damage in Alzheimer disease (AD). The aim of this study was to investigate erythrocyte membrane stability and plasma antioxidant status in AD. Fasting blood samples (from 17 patients with AD and 14 healthy controls) were obtained and erythrocyte membrane stability against hydrogen peroxide and 2,2'-azobis-(2-amidinopropane) dihydrochloride (AAPH), serum Trolox equivalent antioxidant capacity (TEAC), residual antioxidant activity or gap (GAP), erythrocyte catalase activity (CAT), erythrocyte superoxide dismutase (SOD) activity, erythrocyte nonproteic thiols, and total plasma thiols were determined. A significant decrease in erythrocyte membrane stability to hydrogen peroxide was found in AD patients when compared with controls (P<0.05). On the contrary, CAT activity (P<0.0001) and total plasma thiols (P<0.05) were increased in patients with AD compared with controls. Our results indicate that the most satisfactory measurement of the oxidative stress level in the blood of patients with AD is the erythrocyte membrane stability to hydrogen peroxide. Reduced erythrocyte membrane stability may be further evaluated as a potential peripheral marker for oxidative damage in AD.

  8. Hormetic concentrations of hydrogen peroxide but not ethanol induce cross-adaptation to different stresses in budding yeast.

    PubMed

    Semchyshyn, Halyna M

    2014-01-01

    The biphasic-dose response of microorganisms to hydrogen peroxide is a phenomenon of particular interest in hormesis research. In different animal models, the dose-response curve for ethanol is also nonlinear showing an inhibitory effect at high doses but a stimulatory effect at low doses. In this study, we observed the hormetic-dose response to ethanol in budding yeast S. cerevisiae. Cross-protection is a phenomenon in which exposure to mild stress results in the acquisition of cellular resistance to lethal stress induced by different factors. Since both hydrogen peroxide and ethanol at low concentrations were found to stimulate yeast colony growth, we evaluated the role of one substance in cell cross-adaptation to the other substance as well as some weak organic acid preservatives. This study demonstrates that, unlike ethanol, hydrogen peroxide at hormetic concentrations causes cross-resistance of S. cerevisiae to different stresses. The regulatory protein Yap1 plays an important role in the hormetic effects by low concentrations of either hydrogen peroxide or ethanol, and it is involved in the yeast cross-adaptation by low sublethal doses of hydrogen peroxide.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Ulinastatin Suppresses Burn-Induced Lipid Peroxidation and Reduces Fluid Requirements in a Swine Model

    PubMed Central

    Luo, Hong-Min; Du, Ming-Hua; Lin, Zhi-Long; Hu, Quan; Zhang, Lin; Ma, Li; Wang, Huan; Wen, Yu; Lv, Yi; Lin, Hong-Yuan; Pi, Yu-Li; Hu, Sen; Sheng, Zhi-Yong

    2013-01-01

    Objective. Lipid peroxidation plays a critical role in burn-induced plasma leakage, and ulinastatin has been reported to reduce lipid peroxidation in various models. This study aims to examine whether ulinastatin reduces fluid requirements through inhibition of lipid peroxidation in a swine burn model. Methods. Forty miniature swine were subjected to 40% TBSA burns and were randomly allocated to the following four groups: immediate lactated Ringer's resuscitation (ILR), immediate LR containing ulinastatin (ILR/ULI), delayed LR resuscitation (DLR), and delayed LR containing ulinastatin (DLR/ULI). Hemodynamic variables, net fluid accumulation, and plasma thiobarbituric acid reactive substances (TBARS) concentrations were measured. Heart, liver, lung, skeletal muscle, and ileum were harvested at 48 hours after burn for evaluation of TBARS concentrations, activities of antioxidant enzymes, and tissue water content. Results. Ulinastatin significantly reduced pulmonary vascular permeability index (PVPI) and extravascular lung water index (ELWI), net fluid accumulation, and water content of heart, lung, and ileum in both immediate or delayed resuscitation groups. Furthermore, ulinastatin infusion significantly reduced plasma and tissue concentrations of TBARS in both immediate or delayed resuscitation groups. Conclusions. These results indicate that ulinastatin can reduce fluid requirements through inhibition of lipid peroxidation. PMID:23738046

  11. Frost-weathering on Mars: experimental evidence for peroxide formation.

    PubMed

    Huguenin, R L; Miller, K J; Harwood, W S

    1979-12-01

    A laboratory study of the interaction of H2O frost with samples of the minerals olivine (Mg,Fe)2SiO4 and pyroxene (Mg,Fe)SiO3 at -11 degrees C to -22 degrees C revealed that an acidic oxidant was produced. Exposure of the frost-treated minerals to liquie H2O produced a sudden drop in pH and resulted in the production of copious O2(g) (as much as approximately 10(20) molecules g-1). Exposure of frost-treated samples to 5 ml of 0.1M HCOONa solution resulted in the rapid oxidation of up to 43% of the formate to CO2(g). These reactions were qualitatively similar to the chemical activity observed during the active cycles of the Viking lander Gas Exchange and Labeled Release Biology experiments. Attempts to identify the oxidant by chemical indicators were inconclusive, but they tentatively suggested that chemisorbed hydrogen peroxide may have formed. The formation of chemisorbed peroxide could be explained as a byproduct of the chemical reduction of the mineral. The following model was proposed. H+ was incorporated into the mineral from surface frost. This would have left behind a residual of excess OH-(ads) (relative to surface H+). Electrons were then stripped from the surface OH-(ads) (due to the large repulsive potential between neighboring OH-(ads)) and incorporated into the crystal to restore charge balance and produce a chemical reduction of the mineral. The resultant surface hydroxyl radicals could then have combined to form the more stable chemisorbed hydrogen peroxide species. While the chemisorbed peroxide should be relatively stable at low temperatures, it should tend to decay to O(ads)+ H2O(g) at higher temperatures with an activation energy of greater than or approximately 34 kcal mole-1. This is consistent with the long-term storage and sterilization behavior of the Viking soil oxidants. It is possible that as little as 0.1--1% frost-weathered material in the martian soil could have produced the unusual chemical activity that occurred during the Viking Gas

  12. Coupling of Solar Energy to Hydrogen Peroxide Production in the Cyanobacterium Anacystis nidulans

    PubMed Central

    Roncel, Mercedes; Navarro, José A.; De la Rosa, Miguel A.

    1989-01-01

    Hydrogen peroxide production by blue-green algae (cyanobacteria) under photoautotrophic conditions is of great interest as a model system for the bioconversion of solar energy. Our experimental system was based on the photosynthetic reduction of molecular oxygen with electrons from water by Anacystis nidulans 1402-1 as the biophotocatalyst and methyl viologen as a redox intermediate. It has been demonstrated that the metabolic conditions of the algae in their different growth stages strongly influence the capacity for hydrogen peroxide photoproduction, and so the initial formation rate and net peroxide yield became maximum in the mid-log phase of growth. The overall process can be optimized in the presence of certain metabolic inhibitors such as iodoacetamide and p-hydroxymercuribenzoate, as well as by permeabilization of the cellular membrane after drastic temperature changes and by immobilization of the cells in inert supports such as agar and alginate. PMID:16347855

  13. Solar-Driven Hydrogen Peroxide Production Using Polymer-Supported Carbon Dots as Heterogeneous Catalyst

    NASA Astrophysics Data System (ADS)

    Gogoi, Satyabrat; Karak, Niranjan

    2017-10-01

    Safe, sustainable, and green production of hydrogen peroxide is an exciting proposition due to the role of hydrogen peroxide as a green oxidant and energy carrier for fuel cells. The current work reports the development of carbon dot-impregnated waterborne hyperbranched polyurethane as a heterogeneous photo-catalyst for solar-driven production of hydrogen peroxide. The results reveal that the carbon dots possess a suitable band-gap of 2.98 eV, which facilitates effective splitting of both water and ethanol under solar irradiation. Inclusion of the carbon dots within the eco-friendly polymeric material ensures their catalytic activity and also provides a facile route for easy catalyst separation, especially from a solubilizing medium. The overall process was performed in accordance with the principles of green chemistry using bio-based precursors and aqueous medium. This work highlights the potential of carbon dots as an effective photo-catalyst.

  14. Treatment of oily port wastewater effluents using the ultraviolet/hydrogen peroxide photodecomposition system.

    PubMed

    Siedlecka, Ewa Maria; Stepnowski, Piotr

    2006-08-01

    This paper presents the nonselective degradation of mechanically pretreated oily wastewater by hydrogen peroxide (H2O2) in the presence and absence of UV irradiation. The effect of chemical oxidation on wastewater biodegradability was also examined. The exclusive use of H2O2 photolyzed by daylight results in quite efficient degradation rates for the low peroxide concentrations used. Higher hydrogen peroxide concentrations inhibit degradation of organic contaminants in the wastewater. The degradation rates of all contaminants are relatively high with an advanced oxidation system (UV/H2O2), but degradation efficiencies are not distinguishably different when 20 or 45 minutes of UV irradiation is used. The excess of H2O2 used in the process can inhibit phenolic degradation and may lead to the formation of a new phenolic fraction. The biodegradability of port wastewater did not increase significantly following the application of the advanced oxidation process.

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

    PubMed

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

    2008-02-01

    To understand the molecular mechanism of oxidation-induced inhibition of muscle contractility, we have studied the effects of hydrogen peroxide on permeabilized rabbit psoas muscle fibers, focusing on changes in myosin purified from these fibers. Oxidation by 5 mM peroxide decreased fiber contractility (isometric force and shortening velocity) without significant changes in the enzymatic activity of myofibrils and isolated myosin. The inhibitory effects were reversed by treating fibers with dithiothreitol. Oxidation by 50 mM peroxide had a more pronounced and irreversible inhibitory effect on fiber contractility and also affected enzymatic activity of myofibrils, myosin, and actomyosin. Peroxide treatment also affected regulation of contractility, resulting in fiber activation in the absence of calcium. Electron paramagnetic resonance of spin-labeled myosin in muscle fibers showed that oxidation increased the fraction of myosin heads in the strong-binding structural state under relaxing conditions (low calcium) but had no effect under activating conditions (high calcium). This change in the distribution of structural states of myosin provides a plausible explanation for the observed changes in both contractile and regulatory functions. Mass spectroscopy analysis showed that 50 mM but not 5 mM peroxide induced oxidative modifications in both isoforms of the essential light chains and in the heavy chain of myosin subfragment 1 by targeting multiple methionine residues. We conclude that 1) inhibition of muscle fiber contractility via oxidation of myosin occurs at high but not low concentrations of peroxide and 2) the inhibitory effects of oxidation suggest a critical and previously unknown role of methionines in myosin function.

  16. Assay to detect lipid peroxidation upon exposure to nanoparticles.

    PubMed

    Potter, Timothy M; Neun, Barry W; Stern, Stephan T

    2011-01-01

    This chapter describes a method for the analysis of human hepatocarcinoma cells (HEP G2) for lipid peroxidation products, such as malondialdehyde (MDA), following treatment with nanoparticle formulations. Oxidative stress has been identified as a likely mechanism of nanoparticle toxicity, and cell-based in vitro systems for evaluation of nanoparticle-induced oxidative stress are widely considered to be an important component of biocompatibility screens. The products of lipid peroxidation, lipid hydroperoxides, and aldehydes, such as MDA, can be measured via a thiobarbituric acid reactive substances (TBARS) assay. In this assay, which can be performed in cell culture or in cell lysate, MDA combines with thiobarbituric acid (TBA) to form a fluorescent adduct that can be detected at an excitation wavelength of 530 nm and an emission wavelength of 550 nm. The results are then expressed as MDA equivalents, normalized to total cellular protein (determined by Bradford assay).

  17. Fluorescence hydrogen peroxide probe based on a microstructured polymer optical fiber modified with a titanium dioxide film.

    PubMed

    Li, Dongdong; Wang, Lili

    2010-05-01

    A highly sensitive microstructured polymer optical fiber (MPOF) probe for hydrogen peroxide was made by forming a rhodamine 6G-doped titanium dioxide film on the side walls of array holes in an MPOF. It was found that hydrogen peroxide only has a response to the MPOF probe in a certain concentration of potassium iodide in sulfuric acid solution. The calibration graph of fluorescence intensity versus hydrogen peroxide concentration is linear in the range of 1.6 x 10(-7) mol/L to 9.6 x 10(-5) mol/L. The method, with high sensitivity and a wide linear range, has been applied to the determination of trace amounts of hydrogen peroxide in a few real samples, such as rain water and contact lens disinfectant, with satisfactory results.

  18. An effective ostrich oil bleaching technique using peroxide value as an indicator.

    PubMed

    Palanisamy, Uma Devi; Sivanathan, Muniswaran; Radhakrishnan, Ammu Kutty; Haleagrahara, Nagaraja; Subramaniam, Thavamanithevi; Chiew, Gan Seng

    2011-07-05

    Ostrich oil has been used extensively in the cosmetic and pharmaceutical industries. However, rancidity causes undesirable chemical changes in flavour, colour, odour and nutritional value. Bleaching is an important process in refining ostrich oil. Bleaching refers to the removal of certain minor constituents (colour pigments, free fatty acid, peroxides, odour and non-fatty materials) from crude fats and oils to yield purified glycerides. There is a need to optimize the bleaching process of crude ostrich oil prior to its use for therapeutic purposes. The objective of our study was to establish an effective method to bleach ostrich oil using peroxide value as an indicator of refinement. In our study, we showed that natural earth clay was better than bentonite and acid-activated clay to bleach ostrich oil. It was also found that 1 hour incubation at a 150 °C was suitable to lower peroxide value by 90%. In addition, the nitrogen trap technique in the bleaching process was as effective as the continuous nitrogen flow technique and as such would be the recommended technique due to its cost effectiveness.

  19. HISTOCHEMICAL TESTS OF DISCOVERY OF FAT PEROXIDES IN THE EPIDERMIS OF RATS IN LOCAL IRRADIATION

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Godlewski, H.

    1958-01-01

    Fat peroxides were determined according to the method of Dubulo and Duma 0, 3, 6, and 24 hr after single local irradiation of the hip with a dose of 2400 r. Negative results were obtained. However, the peroxides were discovered in irradiated as well as in control animals in places of prolonged restorative degeneration of unknown etiology (panniculus carnosus?).

  20. Dietary Fat Feeding Alters Lipid Peroxidation in Surfactant-like Particles Secreted by Rat Small Intestine.

    PubMed

    Turan, Aasma; Mahmood, Akhtar; Alpers, David H

    2009-04-01

    Long-term feeding of fish oil (n-3) and corn oil (n-6) markedly enhances levels of lipid peroxidation within isolated rat enterocytes. The effect is 10-fold greater at the villus tip than in the crypt region, correlating with the distribution of deleterious oxidative systems (glutathione reductase) in the tip and beneficial systems (superoxide dismutase) at the base of the villus. Because of this vertical gradient of peroxidation, the process was thought to play a role in apoptosis of enterocytes at the villus tip. Surfactant-like particles (SLPs) are membranes secreted by the enterocyte and a component of these membranes is directed to the intestinal surface overlying villus tips. One suggested role for SLPs has been to protect the mucosal surface from the harsh luminal conditions that might enhance apoptotic loss of enterocytes. The hypothesis to be tested was whether SLP lipids, like those in enterocytes, were also peroxidized, although they were external to the cellular processes that seem to oxidize enterocyte lipids, or whether SLP were immune to these biological processes. Feeding with groundnut oil (n-9) was compared with fish oil (n-3) and corn oil (predominantly n-6) to determine whether oils with various lipid composition would affect peroxidation in both SLP and enterocytes. After an overnight fast, Wistar rats were fed 2 mL of dietary oil by gavage. Five hours later SLPs and underlying microvillus membranes (MVM) were isolated and analyzed for generation of thiobarbituric acid reactive substances (TBARS) and for hydrolase activities, at baseline and after addition of an Fe +2 /ascorbate system to induce peroxidation. In vitro lipid peroxidation using the Fe 2+ /ascorbate system produced greater peroxidation than in MVM. Intestinal alkaline phosphatase (IAP), sucrase and lactase activities were decreased in SLPs, but were unaltered in MVM except for IAP. The activities of maltase, trehalase, Leucine aminopeptidase and γ-glutamyltranspeptidase, were