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Sample records for 99mtc methylene diphosphonate

  1. Extraosseous accumulation of bone scan tracer (99m)Tc-methylene diphosphonate in a phlebolith.

    PubMed

    Kulkarni, Mukta; Agrawal, Archi; Zade, Anand; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2012-01-01

    Uptake in non-osseous, non-urologic tissues is occasionally found in the performance of bone scintigraphy. These uptakes reflect an atypical interaction between the radiopharmaceutical and the patient. Knowledge of the rare extraskeletal uptakes and their clinical relevance helps in better interpretation of bone scans. We report an unusual occurrence of extraosseous accumulation of (99m)Tc-methylene diphosphonate in a phlebolith in bone scan, confirmed with the aid of photon emission computed tomography and computed tomography. PMID:23599599

  2. Extraosseous accumulation of bone scan tracer 99mTc-methylene diphosphonate in a phlebolith

    PubMed Central

    Kulkarni, Mukta; Agrawal, Archi; Zade, Anand; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2012-01-01

    Uptake in non-osseous, non-urologic tissues is occasionally found in the performance of bone scintigraphy. These uptakes reflect an atypical interaction between the radiopharmaceutical and the patient. Knowledge of the rare extraskeletal uptakes and their clinical relevance helps in better interpretation of bone scans. We report an unusual occurrence of extraosseous accumulation of 99mTc-methylene diphosphonate in a phlebolith in bone scan, confirmed with the aid of photon emission computed tomography and computed tomography. PMID:23599599

  3. (99m)Tc-methylene diphosphonate bone scintigraphy findings in posttransplant distal limb syndrome.

    PubMed

    Derlin, Thorsten; Busch, Jasmin D; Bannas, Peter

    2014-07-01

    We report a case of posttransplant distal limb syndrome (PTDLS) representing a rare complication in kidney transplant recipients characterized by a pain syndrome of the distal extremities. A 68-year-old man with a history of kidney transplantation presented with symmetrical and incapacitating pain in the feet and knees and underwent whole-body Tc-methylene diphosphonate (MDP) scintigraphy for further evaluation. Planar scintigraphy demonstrated marked tracer uptake in the distal femoral and tibial epiphyses, and magnetic resonance imaging showed corresponding osteoedema. Tc-MDP scintigraphy is a valuable tool for evaluation of the etiology of musculoskeletal pain and may demonstrate typical findings in case of PTDLS.

  4. Technetium 99m-methylene diphosphonate bone scans in children with reflex neurovascular dystrophy

    SciTech Connect

    Laxer, R.M.; Allen, R.C.; Malleson, P.N.; Morrison, R.T.; Petty, R.E.

    1985-03-01

    Eleven children with reflex neurovascular dystrophy were investigated by technetium-labeled methylene diphosphonate bone scanning. Eight of 12 scans demonstrated abnormal findings, four showing diffusely decreased uptake and four diffusely increased uptake of the radionuclide in the affected site. Three scans showed normal findings initially, as did one previously abnormal scan when repeated in the asymptomatic patient 6 months later. Diffusely abnormal findings can be helpful in the diagnosis of childhood reflex neurovascular dystrophy, but a normal scan does not exclude the diagnosis.

  5. SUV measurement of normal vertebrae using SPECT/CT with Tc-99m methylene diphosphonate

    PubMed Central

    Kaneta, Tomohiro; Ogawa, Matsuyoshi; Daisaki, Hiromitsu; Nawata, Shintaro; Yoshida, Keisuke; Inoue, Tomio

    2016-01-01

    The purpose of this study is to perform quantitative measurement based on the standardized uptake value (SUV) of the uptake of Tc-99m methylene diphosphonate (MDP) in the normal vertebrae using a single photon emission tomography (SPECT)/computed tomography (CT) scanner. A retrospective study of patients with cancer or joint disorders was performed. We acquired data for a group of 29 patients (8 women and 21 men; mean age, 68.2 ± 6.7 years; age range, 44-87 years) undergoing bone SPECT/CT scans with Tc-99m MDP between September and October 2015. Various SUVs were calculated based on body-weight, lean-body-weight (lbw), Japanese lean-body-weight (jlbw) and Japanese bone-mineral-content (jbmc). SUVs of normal vertebrae showed a wide range of values. Among these, the maximum body-weight based SUV showed the lowest coefficient of variation. The SUVs also showed relatively small intra-subject variability. In addition, all SUVs showed moderate and significant correlation with height. Moreover, lbw-, jlbw-, and jbmc-based SUVs of men were significantly higher than those of women. In conclusions, SUVs of normal vertebrae showed a relatively large inter-individual variability and small intra-individual variability. As a quantitative imaging biomarker, SUVs might require standardization with adequate reference data for the same subject to minimize variability. PMID:27766184

  6. Desensitization of the guinea-pig urinary bladder by the enantiomers of adenylyl 5'-(beta, gamma-methylene)-diphosphonate and by substance P.

    PubMed Central

    Hourani, S. M.

    1984-01-01

    Adenosine 5'-triphosphate (ATP), substance P (SP) and non-cholinergic nerve stimulation contracted the guinea-pig urinary bladder. SP and two poorly-degradable analogues of ATP, the enantiomers of adenylyl 5'-(beta, gamma-methylene)-diphosphonate (AMP-PCP and L-AMP-PCP), were used to desensitize the guinea-pig bladder. Desensitization of the bladder by AMP-PCP (50 microM) or by L-AMP-PCP (50 microM) abolished the responses to ATP, and inhibited the responses to non-cholinergic nerve stimulation and to SP. The responses to histamine were unaffected. Desensitization by SP (1 microM) inhibited the responses to SP itself, but not the responses to ATP, L-AMP-PCP or non-cholinergic nerve stimulation. These results suggest that SP may act partly by releasing ATP, and support the suggestion that ATP rather than SP is the non-cholinergic stimulatory transmitter. PMID:6203588

  7. Evaluating disease activity in patients with ankylosing spondylitis and rheumatoid arthritis using 99mtc-glucosamine

    PubMed Central

    Manolios, Nicholas; Ali, Marina; Camden, Bradley; Aflaky, Elham; Pavic, Katrina; Markewycz, Andrew; De Costa, Robert; Angelides, Socrates

    2016-01-01

    Objective To evaluate the clinical utility of a novel radiotracer, 99mTc-glucosamine, in assessing disease activity of both rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Material and Methods: Twenty-five patients with RA (nine males and 16 females) and 12 patients with AS (all male) at various stages of disease were recruited for the study. A clinical history and examination was performed, followed by the measurement of hematological, biochemical, and autoimmune serological parameters to assess disease activity. 99mTc-glucosamine was intravenously administered and scans were compared with other imaging modalities, including plain X-ray, magnetic resonance imaging (MRI), and bone scans. Results In patients with AS, 99mTc-glucosamine scans were more capable of identifying active disease and differentiating between inflammatory and non-inflammatory causes. In patients with RA, 99mTc-glucosamine accumulated at all known sites of disease involvement. Uptake was most pronounced in patients with active untreated disease. The relative tracer activity in the involved joints increased with time compared with that in the adjoining soft tissue, liver, and cardiac blood pool. Using Spearman’s correlation coefficient, there was a positive correlation among glucosamine scan scores, C-reactive protein (p=0.048), and clinical assessment (p=0.003), which was not noted with bone scans. Conclusion The radiotracer was well tolerated by all patients, with no adverse reactions. 99mTc-glucosamine imaging could detect spinal inflammation in AS. With respect to RA, 99mTc-glucosamine was a viable alternative to 99mTc-labeled methylene diphosphonate nuclear bone scans for imaging inflamed joints and had the added advantage of demonstrating a significant clinical correlation between disease activity and scan findings. PMID:27708974

  8. Dystrophic calcification in muscles of legs in calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia syndrome: Accurate evaluation of the extent with (99m)Tc-methylene diphosphonate single photon emission computed tomography/computed tomography.

    PubMed

    Chakraborty, Partha Sarathi; Karunanithi, Sellam; Dhull, Varun Singh; Kumar, Kunal; Tripathi, Madhavi

    2015-01-01

    We present the case of a 35-year-old man with calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia variant scleroderma who presented with dysphagia, Raynaud's phenomenon and calf pain. (99m)Tc-methylene diphosphonate bone scintigraphy was performed to identify the extent of the calcification. It revealed extensive dystrophic calcification in the left thigh and bilateral legs which was involving the muscles and was well-delineated on single photon emission computed tomography/computed tomography. Calcinosis in scleroderma usually involves the skin but can be found in deeper periarticular tissues. Myopathy is associated with a poor prognosis.

  9. Studies on the Labeling of Ethylenediaminetetramethylene Phosphonic Acid, Methylene Diphosphonate, Sodium Pyrophosphate and Hydroxyapatite with Lutetium-177 for use in Nuclear Medicine.

    PubMed

    Abbasi, Imtiaz Ahmed

    2015-01-01

    For the treatment of skeletal metastasis, a therapeutic radionuclide tagged with a bone seeking ligand is required, while for radiation synovectomy (RS), a therapeutic radionuclide irreversibly attached to pre-formed particles of appropriate size is required. Radio lanthanides are mostly therapeutic, and ligands containing phosphate groups are predominantly bone seekers. Exploiting these facts, number of new therapeutic radiopharmaceuticals could be developed. Labeling of four phosphate containing materials was pursued in the present study. It was hypothesized that various (177)Lu-labeled bone-seeking complexes such as (177)Lu-ethylenediaminetetramethylene phosphonic acid (EDTMP), (177)Lu-methylene diphosphonate (MDP) and (177)Lu-pyrophosphate (PYP) could be developed as agents for palliative radiotherapy of bone pain due to skeletal metastases, and (177)Lu-Hydroxyapatite (HA) could be developed as an agent for radiosynovectomy of small joints. Lyophilized kit vials of EDTMP, MDP and sodium pyrophosphate (Na-PYP) were formulated. HA particles were synthesized locally and purity was checked by high-performance liquid chromatography (HPLC). (177)Lu was labeled with EDTMP, MDP, PYP, and HA and the behavior of all was studied by radio-thin layer chromatography (TLC) radio-HPLC and radio-electrophoresis. Radio-TLC confirmed the labeling. HPLC analysis too verified the labeling. Radio-electrophoresis results depicted peaks for (177)Lu-MDP, (177)Lu-EDTMP and (177)Lu-PYP at 3.37 ± 0.06 cm, 5.53 ± 0.15 cm and 7.03 ± 0.06 cm respectively confirming negative charge on each specie as all migrated toward positive anode. All 3 methods verified the labeling. The study demonstrated that EDTMP, MDP and PYP form stable complexes with (177)Lu in injectable solution form. HA particulates could too be labeled with (177)Lu with high radiochemical yields (>98%) in suspension form. Former three could be utilized as bone-pain palliation agents for the treatment of bone metastases, and

  10. Voltammetry as a virtual potentiometric sensor in modelling of a metal-ligand system and refinement of stability constants. Part 4. An electrochemical study of NiII complexes with methylene diphosphonic acid.

    PubMed

    Cukrowski, Ignacy; Mogano, Daniel M; Zeevaart, Jan Rijn

    2005-12-01

    The Ni(II)-MDP-OH system (MDP=methylene diphosphonic acid) and stability constants of complexes formed at ionic strength 0.15M at 298K were established by direct current polarography (DCP) and glass electrode potentiometry (GEP). The final M-L-OH model could only be arrived to by employing recent concept of virtual potentiometry (VP). VP-data were generated from non-equilibrium and dynamic DC polarographic technique. The VP and GEP data were refined simultaneously by software dedicated to potentiometric studies of metal complexes. Species distribution diagrams that were generated for different experimental conditions employed in this work assisted in making the final choice regarding the metal-ligand model. The model established contains ML, ML(2), ML(OH) and ML(OH)(2) with stability constants, as logbeta, 7.94+/-0.02, 13.75+/-0.02, 12.04 (fixed value), and 16.75+/-0.05, respectively. It has been demonstrated that virtual potential must be used in modelling operations (predictions of species formed) when a polarographic signal decreases significantly due to the formation of polarographically inactive species (or formation of inert complexes). The linear free energy relationships that included stability constant logK(1) for Ni(II)-MDP established in this work together with other available data were used to predict logK(1) values for Sm(III) and Ho(III) with MDP. The logK(1) values for Sm(III)-MDP and Ho(III)-MDP were estimated to be 9.65+/-0.10 and 9.85+/-0.10, respectively. PMID:16213588

  11. A comparison of skeletal uptakes of three diphosphonates by whole-body retention: concise communication.

    PubMed

    Fogelman, I; Pearson, D W; Bessent, R G; Tofe, A J; Francis, M D

    1981-10-01

    Twenty normal volunteers had measurements of 24-hr whole-body retention (WBR) of three structurally related Tc-99m-labeled phosphonate skeletal imaging agents: (1-hydroxyethylidene) diphosphonate (HEDP), methylene diphosphonate (MDP), and hydroxymethylene diphosphonate (HMDP). The average WBR values, reflecting skeletal uptake, were 18.4, 30.3, and 36.6%, respectively. These results clearly illustrate that slight alterations in diphosphonate molecular structure have a significant effect upon specificity for osseous tissue, and thus may affect skeletal image quality and the usefulness of the WBR technique in diagnosing metabolic bone disease.

  12. Factors affecting uptake and retention of technetium-99m-diphosphonate and 99m-pertechnetate in osseous, connective and soft tissues.

    PubMed

    Francis, M D; Slough, C L; Tofe, A J

    1976-06-14

    The bone scanning complex, 99mTc-Sn-EHDP, consisting of the nuclide technetium-99m, stannous ion and ethane-1-hydroxy-1,1-diphosphonate, administered intravenously is retained in soft tissues in proportion to increasing calcium content of the tissues. Within bone tissue, the retention is proportional to vascularity and to surface area of calcium phosphate in bones and not necessarily to calcium and phosphate concentration. The nuclidic agent 99mTcO4-BUT NOT THE 99MTc-diphosphonate is selectively taken up by the thyroid and this uptake can be blocked by administering sodium perchlorate. Among the connective tissues studied, the tracheal cartilage seems to have the greatest potential to calcify with increasing age of the animal and man. Soft tissue does not retain the bone scanning complex 99mTc-Sn-EHDP but does retain 99mTcO4-. PMID:182328

  13. Barium uranyl diphosphonates

    SciTech Connect

    Nelson, Anna-Gay D.; Alekseev, Evgeny V.; Ewing, Rodney C.; Albrecht-Schmitt, Thomas E.

    2012-08-15

    Three Ba{sup 2+}/UO{sub 2}{sup 2+} methylenediphosphonates have been prepared from mild hydrothermal treatment of uranium trioxide, methylendiphosphonic acid (C1P2) with barium hydroxide octahydrate, barium iodate monohydrate, and small aliquots of HF at 200 Degree-Sign C. These compounds, Ba[UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{center_dot}1.4H{sub 2}O (Ba-1), Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2}F{sub 6}]{center_dot}6H{sub 2}O (Ba-2), and Ba{sub 2}[(UO{sub 2}){sub 2}(CH{sub 2}(PO{sub 3}){sub 2})F{sub 4}]{center_dot}5.75H{sub 2}O (Ba-3) all adopt layered structures based upon linear uranyl groups and disphosphonate molecules. Ba-2 and Ba-3 are similar in that they both have UO{sub 5}F{sub 2} pentagonal bipyramids that are bridged and chelated by the diphosphonate moiety into a two-dimensional zigzag anionic sheet (Ba-2) and a one-dimensional ribbon anionic chain (Ba-3). Ba-1, has a single crystallographically unique uranium metal center where the C1P2 ligand solely bridges to form [UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sup 2-} sheets. The interlayer space of the structures is occupied by Ba{sup 2+}, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance. - Graphical abstract: Illustration of the stacking of the layers in Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2})F{sub 6}]{center_dot}6H{sub 2}O viewed along the c-axis. The structure is constructed from UO{sub 7} pentagonal bipyramidal units, U(1)O{sub 7}=gray, U(2)O{sub 7}=yellow, barium=blue, phosphorus=magenta, fluorine=green, oxygen=red, carbon=black, and hydrogen=light peach. Highlights: Black-Right-Pointing-Pointer The polymerization of the UO{sub 2}{sup 2+} sites to form uranyl dimers leads to structural variations in compounds. Black-Right-Pointing-Pointer Barium cations stitch uranyl diphosphonate anionic layers together, and help mediate structure formation. Black-Right-Pointing-Pointer HF acts as both a

  14. Adverse allergic reaction to Technetium-99m methylene diphosphonate

    SciTech Connect

    Spicer, J.A.; Preston, D.F.; Stephens, R.L.

    1985-04-01

    Adverse allergic reactions to radiopharmaceuticals are rare but have been documented in the literature. This report presents data consistent with a definite adverse reaction to the radiopharmaceutical (/sup 99m/Tc)MDP.

  15. The Development of Diphosphonates as Significant Health Care Products.

    ERIC Educational Resources Information Center

    Francis, Marion D.; Centner, Rosemary L.

    1978-01-01

    The historical development of the use of diphosphonates in detergents is presented as well as physical chemistry, physiological response, toxicology, and human clinical trials with these compounds. (BB)

  16. Calcium balance in children treated with diphosphonates.

    PubMed

    Uttley, W S; Belton, N R; Syme, J; Sheppard, H

    1975-03-01

    Serial mineral balances have been obtained in 3 children undergoing therapy with EHDP (ethane-1-hydroxy-1, 1-diphosphonate) for diseases involving ectopic calcification. Although clinical outcome was not uniformly satisfactory, all cases showed an overall reduction in calcium balance. This was due to increased faecal excretion of calcium and was most marked after a long duration of therapy. Although these results conflict with reported experience in adults, they are in agreement with published observations of the effects of EHDP on calcium absorption in experimental animals.

  17. Extracting metal ions with diphosphonic acid, or derivative thereof

    DOEpatents

    Horwitz, E.P.; Gatrone, R.C.; Nash, K.L.

    1994-07-26

    Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulfur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described. 1 fig.

  18. Extracting metal ions with diphosphonic acid, or derivative thereof

    DOEpatents

    Horwitz, Earl P.; Gatrone, Ralph C.; Nash, Kenneth L.

    1994-01-01

    Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described.

  19. Membrane extraction with thermodynamically unstable diphosphonic acid derivatives

    DOEpatents

    Horwitz, Earl Philip; Gatrone, Ralph Carl; Nash, Kenneth LaVerne

    1997-01-01

    Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described.

  20. Pillared and open-framework uranyl diphosphonates

    SciTech Connect

    Adelani, Pius O.; Albrecht-Schmitt, Thomas E.

    2011-09-15

    The hydrothermal reactions of uranium trioxide, uranyl acetate, or uranyl nitrate with 1,4-benzenebisphosphonic acid in the presence of very small amount of HF at 200 deg. C results in the formation of three different uranyl diphosphonate compounds, [H{sub 3}O]{sub 2}{l_brace}(UO{sub 2}){sub 6}[C{sub 6}H{sub 4}(PO{sub 3})(PO{sub 2}OH)]{sub 2}[C{sub 6}H{sub 4}(PO{sub 2}OH){sub 2}]{sub 2}[C{sub 6}H{sub 4}(PO{sub 3}){sub 2}]{r_brace}(H{sub 2}O){sub 2} (Ubbp-1), [H{sub 3}O]{sub 4}{l_brace}(UO{sub 2}){sub 4}[C{sub 6}H{sub 4}(PO{sub 3}){sub 2}]{sub 2}F{sub 4}{r_brace}.H{sub 2}O (Ubbp-2), and {l_brace}(UO{sub 2})[C{sub 6}H{sub 2}F{sub 2}(PO{sub 2}OH){sub 2}(H{sub 2}O){r_brace}{sub 2}.H{sub 2}O (Ubbp-3). The crystal structures of these compounds were determined by single crystal X-ray diffraction experiments. Ubbp-1 consists of UO{sub 7} pentagonal bipyramids that are bridged by the phosphonate moieties to form a three-dimensional pillared structure. Ubbp-2 is composed of UO{sub 5}F{sub 2} pentagonal bipyramids that are bridged through the phosphonate oxygen atoms into one-dimensional chains that are cross-linked by the phenyl spacers into a pillared structure. The structure of Ubbp-3 is a three-dimensional open-framework with large channels containing water molecules with internal dimensions of approximately 10.9x10.9 A. Ubbp-1 and Ubbp-2 fluoresce at room temperature. - Graphical Abstract: Illustration of the three-dimensional open-framework structure of {l_brace}(UO{sub 2})[C{sub 6}H{sub 2}F{sub 2}(PO{sub 2}OH){sub 2}(H{sub 2}O){r_brace}{sub 2}.H{sub 2}O viewed along the c-axis. The structure is constructed from UO{sub 7} units, pentagonal bipyramids=green, oxygen=red, phosphorus=magenta, carbon=black, hydrogen=white. Highlights: > The influence of the uranyl salt anions and pH were critically examined in relation to structural variation. > The acetate and nitrate counter ions of uranyl may be acting as structure directing agents. > The use of rigid phenyl spacer yield

  1. Radionuclide evaluation of free vascularized bone graft viability. [/sup 99m/Tc-methylene diphosphonate

    SciTech Connect

    Lisbona, R.; Rennie, W.R.J.; Daniel, R.K.

    1980-02-01

    Free vascularized bone grafting is a new technique applied to the reconstructive surgery of long bones affected by aggressive benign or malignant processes, as well as traumatic deficiencies. These bone lesions may be treated by en bloc excision and replacement with fibular segments or osteocutaneous flaps from the groin isolated on their vascular pedicle. Microvascular anastomosis of the pedicle at the recipient site is necessary. Radionuclide bone imaging is unique in the assessment of the free vascularized bone graft because postoperative graft uptake of radiopharmaceutical reflects patent anastomoses and segmental bone viability.

  2. Benign Brenner tumor of the ovary detected on Tc-99m methylene diphosphonate bone scan

    SciTech Connect

    Renner, J.B.; McCartney, W.H.

    1984-11-01

    Many disease states, including neoplasia, have been detected by bone scanning. Among the neoplastic processes detected by bone imaging agents are ovarian tumors, both benign and malignant. This report is concerned with the visualization of a benign Brenner tumor during routine Tc-99m MDP bone scanning.

  3. Technetium-99m-methylene diphosphonate uptake in the fetal skeleton at 30 weeks gestation

    SciTech Connect

    McKenzie, A.F.; Budd, R.S.; Yang, C.

    1994-08-01

    Retention of {sup 99m}Tc-MDP in the fetal skeleton and placenta at 30 and 32 wk gestation was observed during bone scan examination of the maternal skeleton for staging of malignant tumors. The implications and significance of these observations are discussed. 8 refs., 2 figs., 1 tab.

  4. Uranium diphosphonates templated by interlayer organic amines

    SciTech Connect

    Nelson, Anna-Gay D.; Alekseev, Evgeny V.; Albrecht-Schmitt, Thomas E.; Ewing, Rodney C.

    2013-02-15

    The hydrothermal treatment of uranium trioxide and methylenediphosphonic acid with a variety of amines (2,2-dipyridyl, triethylenediamine, ethylenediamine, and 1,10-phenanthroline) at 200 Degree-Sign C results in the crystallization of a series of layered uranium diphosphonate compounds, [C{sub 10}H{sub 9}N{sub 2}]{l_brace}UO{sub 2}(H{sub 2}O)[CH{sub 2}(PO{sub 3})(PO{sub 3}H)]{r_brace} (Ubip2), [C{sub 6}H{sub 14}N{sub 2}]{l_brace}(UO{sub 2}){sub 2}[CH{sub 2}(PO{sub 3})(PO{sub 3}H)]{sub 2}{center_dot}2H{sub 2}O{r_brace} (UDAB), [C{sub 2}H{sub 10}N{sub 2}]{sub 2}{l_brace}(UO{sub 2}){sub 2}(H{sub 2}O){sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sub 2}{center_dot}0.5H{sub 2}O{r_brace} (Uethyl), and [C{sub 12}H{sub 9}N{sub 2}]{l_brace}UO{sub 2}(H{sub 2}O)[CH{sub 2}(PO{sub 3})(PO{sub 3}H)]{r_brace} (Uphen). The crystal structures of the compounds are based on UO{sub 7} units linked by methylenediphosphonate molecules to form two-dimensional anionic sheets in Ubip2 and UDAB, and one-dimensional anionic chains in Uethyl and Uphen, which are charge balanced by protonated amine molecules. Interaction of the amine molecules with phosphonate oxygens and water molecules results in extensive hydrogen bonding in the interlayer. These amine molecules serve both as structure-directing agents and charge-balancing cations for the anionic uranium phosphonate sheets and chains in the formation of the different coordination geometries and topologies of each structure. Reported herein are the syntheses, structural and spectroscopic characterization of the synthesized compounds. - Graphical abstract: The Raman spectra of the synthesized compounds and an illustration of the stacking of the layers with the diprotonated triethylenediamine molecules in [C{sub 6}H{sub 14}N{sub 2}]{l_brace}(UO{sub 2}){sub 2}[CH{sub 2}(PO{sub 3})(PO{sub 3}H)]{sub 2}{center_dot}2H{sub 2}O{r_brace} UDAB. Solvent water molecules are removed for clarity. The corresponding Raman spectra for the complexes synthesized is also

  5. 78 FR 25699 - 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From India: Preliminary Results of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-02

    ... International Trade Administration 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From India: Preliminary Results of... (the Department) is conducting an administrative review of the antidumping duty order on 1- hydroxyethylidene-1, 1-diphosphonic acid (HEDP) from India. The period of review (POR) is April 1, 2011,...

  6. [Evaluation of multiple myeloma with bone scintigraphy using Tc 99 diphosphonate. Review of the literature].

    PubMed

    Solis, O J; Gonzales, R; De Luca, S; McKusick, K A; Potsaid, M S

    1977-04-01

    Bone Scanning using 99m Tc-Diphosphonate is another diagnostic modality in the evaluation of multiple mieloma which allows the identification of bone lesions not demonstrable by conventional radiography. The use of 99m Tc-Diphosphonate is more convenient and less harmful than other radioactive isotopes utilized before. PMID:866897

  7. Diphosphonates in the evaluation of metabolic bone disease.

    PubMed

    Fogelman, I; Smith, M L

    1982-03-01

    The bone scan may be of value in the assessment of patients with metabolic bone disease. However the superiority of the bone scan when compared to radiology in conditions such as renal osteodystrophy, osteomalacia, primary hyperparathyroidism, and osteoporosis requires substantiation with the newer radiopharmaceuticals which have a higher affinity for bone. Two methods of quantitating skeletal uptake of tracer have been assessed to try to remove the subjective aspect of bone scan evaluation. Measurements of bone to soft tissue ratios have proved clinically disappointing, but 24 hour whole body retention of diphosphonate appears to provide a sensitive index of increased bone turnover.

  8. Estimation of Organ Absorbed Doses in Patients from 99mTc-diphosphonate Using the Data of MIRDose Software

    PubMed Central

    Shahbazi-Gahrouei, Daryoush; Cheki, Mohsen; Moslehi, Masoud

    2012-01-01

    The purpose of this study was to compare estimation of radiation absorbed doses to patients following bone scans with technetium-99m-labeled methylene diphosphonate (MDP) with the estimates given in MIRDose software. In this study, each patient was injected 25 mCi of 99mTc-MDP. Whole-body images from thirty patients were acquired by gamma camera at 10, 60, 90, 180 minutes after 99mTc-MDP injection. To determine the amount of activity in each organ, conjugate view method was applied on images. MIRD equation was then used to estimate absorbed doses in different organs of patients. At the end, absorbed dose values obtained in this study were compared with the data of MIRDose software. The absorbed doses per unit of injected activity (mGy/MBq × 10–4) for liver, kidneys, bladder wall and spleen were 3.86 ± 1.1, 38.73 ± 4.7, 4.16 ± 1.8 and 3.91 ± 1.3, respectively. The results of this study may be useful to estimate the amount of activity that can be administered to the patient and also showed that methods used in the study for absorbed dose calculation is in good agreement with the data of MIRDose software and it is possible to use by a clinician. PMID:23724374

  9. Severe systemic reaction to diphosphonate bone imaging agents: skin testing to predict allergic response and a safe alternative agent

    SciTech Connect

    Ramos-Gabatin, A.; Orzel, J.A.; Maloney, T.R.; Murnane, J.E.; Borchert, R.D.

    1986-09-01

    We describe a severe systemic reaction which occurred in a patient on two occasions after i.v. injection of chemically related diphosphonate bone imaging agents. Skin testing showed reactivity to multiple commercially available diphosphonate compounds but no significant response to pyrophosphates. A subsequent pyrophosphate bone scan resulted in no adverse reaction. Severe systemic reactions to diphosphonates can occur, skin testing may prove useful in evaluating allergic reactions, and pyrophosphates appear to be a safe alternative agent in patients proven or suspected allergic to diphosphonates.

  10. Water Oxidation by Ruthenium Complexes Incorporating Multifunctional Bipyridyl Diphosphonate Ligands.

    PubMed

    Xie, Yan; Shaffer, David W; Lewandowska-Andralojc, Anna; Szalda, David J; Concepcion, Javier J

    2016-07-01

    We describe herein the synthesis and characterization of ruthenium complexes with multifunctional bipyridyl diphosphonate ligands as well as initial water oxidation studies. In these complexes, the phosphonate groups provide redox-potential leveling through charge compensation and σ donation to allow facile access to high oxidation states. These complexes display unique pH-dependent electrochemistry associated with deprotonation of the phosphonic acid groups. The position of these groups allows them to shuttle protons in and out of the catalytic site and reduce activation barriers. A mechanism for water oxidation by these catalysts is proposed on the basis of experimental results and DFT calculations. The unprecedented attack of water at a neutral six-coordinate [Ru(IV) ] center to yield an anionic seven-coordinate [Ru(IV) -OH](-) intermediate is one of the key steps of a single-site mechanism in which all species are anionic or neutral. These complexes are among the fastest single-site catalysts reported to date. PMID:27166584

  11. Loosening of the total knee arthroplasty: detection by radionuclide bone scanning. [/sup 99m/Tc-methylene diphosphonate

    SciTech Connect

    Hunter, J.C.; Hattner, R.S.; Murray, W.R.; Genant, H.K.

    1980-07-01

    Pain after total knee arthroplasty is a common clinical problem in orthopedics, and prosthetic loosening, often requiring surgical revision, is usually the etiology. Since standard clinical and radiographic diagnostic measures have not proven totally satisfactory, a study of the utility of bone scintigraphy to assess stability of the knee prosthesis was done. Thirty-five patients with 39 prostheses were studied. Seventeen patients with 21 total knee arthroplasties served as controls and were asymptomatic, were stable at surgery, or improved with conservative management. Eighteen knees in 18 symptomatic patients composed the experimental group. Of these, 11 knees were loose at surgery and seven have had surgery recommended. Scintigrams of the knees were obtained using /sup 99m/Tc-MDP, and ranked 0-3 corresponding to increasingly abnormal localization by three observers. Highly significant differences were observed between the abnormal and control groups (p<0.001). Reciprocal changes in sensitivity and specificity with increasingly stringent criteria were shown. While it is apparent that the bone scan cannot be used as the sole diagnostic method for evaluation of prosthetic stability, it does seem to be a useful adjunct along with clinical criteria and radiographic studies.

  12. 76 FR 772 - 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From the People's Republic of China: Amended Final...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-06

    ... India and the People's Republic of China: Antidumping Duty Orders, 74 FR 19197 (April 28, 2009...-Diphosphonic Acid From the People's Republic of China: Notice of Decision of the Court of International Trade... International Trade Administration 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From the People's Republic...

  13. Delayed skin rash following administration of technetium-99m diphosphonate: A case report

    SciTech Connect

    Hart, B.; Sorenson, J.F.; Eisenberg, B.; Glactz, G.; Owens, D.; Hladik, W.B. III.; Curry, M.C. )

    1989-12-01

    The authors report a case of a 48-yr-old woman who developed a delayed skin rash following intravenous (i.v.) administration of technetium-99m hydroxymethylene diphosphonate ({sup 99m}Tc-HDP). The rash was characterized by skin biopsy, and it was concluded that the reaction was due to the diphosphonate compound. The rash resolved spontaneously without treatment. With most {sup 99m}Tc-based agents, adverse reactions are considered rare and are usually allergic in nature, but the delayed nature of this reaction is more common with diphosphonate compounds than with other radiopharmaceuticals. If a repeat examination is required, alternative agents (such as {sup 99m}Tc-pyrosphosphate) or any other diagnostic modality (magnetic resonance imaging) may be considered. An intradermal skin test may be helpful to determine the safest alternative bone agent.

  14. Thorium and uranium diphosphonates: Syntheses, structures, and spectroscopic properties

    SciTech Connect

    Adelani, Pius O.; Albrecht-Schmitt, Thomas E.

    2012-08-15

    Four new thorium and uranium diphosphonate compounds, [H{sub 3}O]{l_brace}Th{sub 2}[C{sub 6}H{sub 4}(PO{sub 3}){sub 2}]{sub 2}F{r_brace} (Thbbp-1), An{sub 2}{l_brace}(O{sub 3}PC{sub 6}H{sub 4}PO{sub 3}H){sub 2}[C{sub 6}H{sub 4}(PO{sub 3}H){sub 2}]{r_brace} [An=Th(IV), U(IV)] (Thbbp-2)/(U4bbp), and [(C{sub 2}H{sub 5})(CH{sub 3}){sub 3}N][(UO{sub 2}){sub 3}(O{sub 3}PC{sub 6}H{sub 4}PO{sub 3}H){sub 2}F(H{sub 2}O)] (U6bbp) have been synthesized hydrothermally using 1,4-benzenebisphosphonic acid as ligand. The crystal structures of these compounds were determined by single crystal X-ray diffraction. Thbbp-1 and Thbbp-2 contain seven-coordinate Th(IV) within ThO{sub 6}F and ThO{sub 7} units with capped trigonal prismatic and capped octahedral geometries, respectively. U4bbp is isotypic with Thbbp-2. The structure of U6bbp contains U(VI) is the common seven-coordinate pentagonal bipyramid. - Graphical abstract: Coordination polyhedra and luminescence properties in thorium and uranium compounds. Highlights: Black-Right-Pointing-Pointer Three-dimensional thorium and uranium complexes. Black-Right-Pointing-Pointer Conversion of U(VI) to U(IV) under hydrothermal condition. Black-Right-Pointing-Pointer Unusual seven-coordinate thorium complexes exhibiting capped octahedral and capped trigonal prismatic geometries.

  15. 76 FR 19325 - 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From the People's Republic of China: Preliminary...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-07

    ...-Diphosphonic Acid from India and the People's Republic of China: Antidumping Duty Orders, 74 FR 19197 (April 28... Less Than Fair Value: Sparklers From the People's Republic of China, 56 FR 20588, 20589 (May 6, 1991... Determination of Sales at Less Than Fair Value: Silicon Carbide From the People's Republic of China, 59 FR......

  16. 77 FR 15357 - 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From India: Final Results of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-15

    ...-Hydroxyethylidene-1, 1-Diphosphonic Acid from India (76 FR 78237). We invited parties to comment on the preliminary... from India: Notice of Final Determination of Sales at Less Than Fair Value, 74 FR 10543 (March 11, 2009...: Assessment of Antidumping Duties, 68 FR 23954 (May 6, 2003) (Assessment Policy Notice). This...

  17. Increase in alkaline phosphatase activity in calvaria cells cultured with diphosphonates.

    PubMed Central

    Felix, R; Fleisch, H

    1979-01-01

    1. Dichloromethanediphosphonate and to a lesser degree 1-hydroxyethane-1,1-diphosphonate, two compounds characterized by a P-C-P bond, increased the alkaline phosphatase activity of cultured rat calvaria cells up to 30 times in a dose-dependent fashion. 2. Both diphosphonates also slightly inhibited the protein synthesis in these cells. 3. Thymidine, an inhibitor of cell division, did not inhibit the induction of the enzyme, indicating that the increase in enzyme activity was not due to the formation of a specific population of cells with high alkaline phosphatase activity. 4. The effect on alkaline phosphatase was suppressed by the addition of cycloheximide, an inhibitor of protein synthesis. 5. After subculturing the stimulated cells in medium without diphosphonates, the enzyme activity fell almost to the control value. 6. Bovine parathyrin diminished the enzyme activity of the control cells and the cells treated with dichloromethanediphosphonate; however, at high concentration the effect of parathyrin was greater on the diphosphonate-treated cells than on the control cells. 7. The electrophoretic behaviour, heat inactivation, inhibition by bromotetramisole or by phenylalanine, and the Km value of the induced enzyme were identical with that of the control enzyme. PMID:534490

  18. 78 FR 38941 - 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From India: Rescission of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ... Request Administrative Review, 78 FR 19645, 19646 (April 2, 2013). On April 29, 2013, in accordance with... Reviews and Request for Revocation in Part, 78 FR 33052, 33054 (June 3, 2013). \\4\\ See June 4, 2013... International Trade Administration 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From India: Rescission...

  19. 76 FR 7532 - 1-Hydroxyethylidene-1, 1-Diphosphonic Acid from India: Final Results of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-10

    ...-Hydroxyethylidene-1, 1-Diphosphonic Acid from India (75 FR 73042). We invited parties to comment on the preliminary...: Assessment of Antidumping Duties, 68 FR 23954 (May 6, 2003) (Assessment Policy Notice). This clarification... from India: Notice of Final Determination of Sales at Less Than Fair Value, 74 FR 10543 (March 11,...

  20. Aggregation of dialkyl-substituted diphosphonic acids and its effect on metal ion extraction.

    SciTech Connect

    Chiarizia, R.; Barrans, R. E., Jr.; Ferraro, J. R. Herlinger, A. W.; McAlister, D. R.

    1999-10-22

    Solvent extraction reagents containing the diphosphonic acid group exhibit an extraordinary affinity for tri-, tetra- and hexavalent actinides. Their use has been considered for actinide separation and pre-concentration procedures. Solvent extraction data obtained with P,P{prime}-di(2-ethylhexyl) methane-, ethane- and butanediphosphonic acids exhibit features that are difficult to explain without Knowledge of the aggregation state of the extractants. Information about the aggregation of the dialkyl-substituted diphosphonic acids in aromatic diluents has been obtained using the complementary techniques of vapor pressure osmometry (VPO), small angle neutron scattering (SANS), infrared spectroscopy and molecular mechanics. The results from these techniques provide an understanding of the aggregation behavior of these extractants that is fully compatible with the solvent extraction data. The most important results and their relevance to solvent extraction are reviewed in this paper.

  1. Diphosphonate thin films on zinc: Preparation, structure characterization and corrosion protection effects

    NASA Astrophysics Data System (ADS)

    Pilbáth, A.; Bertóti, I.; Sajó, I.; Nyikos, L.; Kálmán, E.

    2008-12-01

    The reaction of water-based solution of 1,5-diphosphono-pentane (DPP) and 1,7-diphosphono-heptane (DPH) with high purity polycrystalline zinc surface was investigated at room temperature. XRD and XPS studies evidenced the formation of crystalline zinc-phosphonate film on the metal surface. The formed layers give hydrophilic properties to the surface. A conversion-type interaction of diphosphonic acid compounds with the oxidized zinc surface was unambiguously shown by XPS analysis. Conclusive results were obtained by synthesized zinc-diphosphonate model compounds imitating the ones developed on the zinc surface, revealing a simple, closely 1:1 ratio of the phosphonate groups with zinc. Reactions with both diphosphonates resulted in significant protective effect of zinc against corrosion, although the structure and quality of the formed layers exhibit marked differences. The in-depth distribution of the composition and dissimilarity of the layer thickness were determined by glow discharge optical emission spectrometry (GD-OES). The corrosion inhibition was explained by the formation of insoluble zinc-phosphonate salt on the zinc surface, blocking the zinc dissolution process.

  2. 76 FR 48142 - 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From the People's Republic of China: Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ... International Trade Administration 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From the People's Republic of... results of the administrative review of the antidumping duty order on 1-hydroxyethylidene-1, 1... through March 31, 2010.\\1\\ The Department gave interested parties an opportunity to comment on...

  3. 75 FR 74684 - 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From the People's Republic of China: Extension of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-01

    ..., 2010. \\1\\ See Initiation of Antidumping and Countervailing Duty Administrative Reviews, 75 FR 29976... International Trade Administration 1-Hydroxyethylidene-1, 1-Diphosphonic Acid From the People's Republic of...: Effective Date: December 1, 2010. FOR FURTHER INFORMATION CONTACT: Shawn Higgins, AD/CVD Operations,...

  4. Thermodynamic Features of Benzene-1,2-Diphosphonic Acid Complexes with Several Metal Ions

    SciTech Connect

    Syouhei Nishihama; Ryan P. Witty; Leigh R Martin; Kenneth L. Nash

    2013-08-01

    Among his many contributions to the advancement of f-element chemistry and separation science, Professor Gregory R. Choppin’s research group completed numerous investigations featuring the application of distribution techniques to the determination of metal complexation equilibrium quotients. Most of these studies focused on the chemistry of lanthanide and actinide complexes. In keeping with that tradition, this report discusses the complex formation equilibrium constants for complexes of trivalent europium (Eu3+) with benzene-1,2-diphosphonic acid (H4BzDP) determined using solvent extraction distribution experiments in 0.2 M (Na,H)ClO4 media in the temperature range of 5 – 45 degrees C. Protonation constants for HnBzDP4-n and stoichiometry and stability of BzDP4- complexes with Zn2+, Ni2+, and Cu2+ have also been determined using potentiometric titration (at I = 0.1 M) and 31P NMR spectroscopy. Heats of protonation of HnBzDPn-4 species have been determined by titration calorimetry. From the temperature dependence of the complex Eu3+-HnBzDPn-4 equilibrium constant, a composite enthalpy (?H = -15.1 (+/-1.0) kJ mol-1) of complexation has been computed. Comparing these thermodynamic parameters with literature reports on other diphosphonic acids and structurally similar carboxylic acids indicates that exothermic heats of complexation are unique to the Eu-BzDP system. Comparisons with thermodynamic data from the literature indicate that the fixed geometry imposed by the benzene ring enhances complex stability.

  5. Hybrid Single-Photon Emission Computed Tomography/Computed Tomography Imaging Features of Tumoral Calcinosis in Technetium-99m Methylene Diphosphonate Bone Scintigraphy

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Asokumar, Premkumar; Malaikkal, Anjali; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2015-01-01

    Tumoral calcinosis (TC) is an uncommon ectopic calcification syndrome. TC is a benign condition characterized by the presence of large calcific soft tissue deposits occurring predominantly in a periarticular location. It generally occurs as a complication of renal dialysis or trauma, and is rarely seen in familial and sporadic cases. Bone scintigraphy is a sensitive method for diagnosing TC. We report a case of year old female with. She underwent bone scintigraphy to see the sites of involvement, which showed intense foci of tracer activity in soft tissue in bilateral thigh and gluteal region. Hybrid single-photon emission computed tomography/computed tomography of the pelvis and thigh localized tracer uptake to the calcification in the gluteal and thigh region. PMID:26097427

  6. Hybrid Single-Photon Emission Computed Tomography/Computed Tomography Imaging Features of Tumoral Calcinosis in Technetium-99m Methylene Diphosphonate Bone Scintigraphy.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Asokumar, Premkumar; Malaikkal, Anjali; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2015-01-01

    Tumoral calcinosis (TC) is an uncommon ectopic calcification syndrome. TC is a benign condition characterized by the presence of large calcific soft tissue deposits occurring predominantly in a periarticular location. It generally occurs as a complication of renal dialysis or trauma, and is rarely seen in familial and sporadic cases. Bone scintigraphy is a sensitive method for diagnosing TC. We report a case of year old female with. She underwent bone scintigraphy to see the sites of involvement, which showed intense foci of tracer activity in soft tissue in bilateral thigh and gluteal region. Hybrid single-photon emission computed tomography/computed tomography of the pelvis and thigh localized tracer uptake to the calcification in the gluteal and thigh region.

  7. Uptake of technetium-99m methylene diphosphonate by fractured and osteoporotic bone after a pulse dose of Vitamin D/sub 3/. [Rats

    SciTech Connect

    Carr, E.A. Jr.; Carroll, M.; Montes, M.; Zielezny, M.

    1985-04-01

    The effect of a pulse dose of Vitamin D/sub 3/ on uptake of (/sup 99m/Tc)MDP by fractured and osteoporotic bone, respectively, was compared with D/sub 3/'s effect on uptake by normal bone in rats. At 4, 7, and 14 days, respectively, after femoral fracture, basal uptake was significantly increased at the fracture site by 336.8, 276.1, and 183.5%, respectively, over the contralateral control site. D/sub 3/-treated rats had lower uptakes than untreated controls at all three fracture sites and at 12 of 15 normal bone sites but analysis of variance showed the uptake differences were not significant. Cortisone-induced osteoporosis caused a significant decrease in basal uptake. The decrease occurred in all nine bone areas studied. D/sub 3/ caused a significant increase in uptake by these osteoporotic bones, but a significant decrease in uptake by the same bones in normal controls. Thus, D/sub 3/ had an effect on uptake by the bone lesion, osteoporosis, that differed from D/sub 3/'s effect on uptake by fracture or normal bone.

  8. Technetium Tc 99m diphosphonate bone scan. False-normal findings in elderly patients with hematogenous vertebral osteomyelitis

    SciTech Connect

    Schlaeffer, F.; Mikolich, D.J.; Mates, S.M.

    1987-11-01

    Hematogenous osteomyelitis is usually diagnosed by an abnormal technetium Tc 99m diphosphonate bone scan in symptomatic patients who have positive blood cultures. False-normal 99mTc bone scans have been described recently in neonates with biopsy-proved osteomyelitis. This phenomenon seems to be extremely rare in adults. Two elderly patients with hematogenous vertebral osteomyelitis had normal technetium Tc 99m diphosphonate bone scans when first evaluated. In both cases the bone scans became abnormal four to six weeks after onset of symptoms and two to four weeks after the initial normal results of the study. When suggested by the clinical picture, hematogenous osteomyelitis cannot be ruled out by a normal 99mTc bone scan at any age. Gallium scan, computed tomographic scan, or bone biopsy can be helpful in such cases.

  9. Structural Investigation of Technetium-Diphosphonate Complex 99mTc-MDP

    NASA Astrophysics Data System (ADS)

    Qiu, Ling; Lin, Jian-guo; Ju, Xue-hai; Gong, Xue-dong; Luo, Shi-neng

    2011-06-01

    Density functional theory method has been employed to investigate the structures of the prototypical technetium-labeled diphosphonate complex 99mTc-MDP, where MDP represents methylenediphosphonic acid. A total of 14 trial structures were generated by allowing for the geometric, conformational, charge, and spin isomerism. Based on the optimized structures and calculated energies at the B3LYP/LANL2DZ level, two stable isomers were determined for the title complex. And they were further studied systematically in comparison with the experimental structure. The basis sets 6-31G*(LANL2DZ for Tc), 6-31G*(cc-pVDZ-pp for Tc), and DGDZVP have also been employed in combination with the B3LYP functional to study the basis set effect on the geometries of isomers. The optimized structures agree well with the available experimental data, and the bond lengths are more sensitive to the basis set than the bond angles. The charge distributions were studied by the Mulliken population analysis and natural bond orbital analysis. The results reflect a significant ligand-to-metal electron donation.

  10. Application of 1-hydroxyethylidene-1, 1-diphosphonic acid in boiler water for industrial boilers.

    PubMed

    Zeng, Bin; Li, Mao-Dong; Zhu, Zhi-Ping; Zhao, Jun-Ming; Zhang, Hui

    2013-01-01

    The primary method used for boiler water treatment is the addition of chemicals to industrial boilers to prevent corrosion and scaling. The static scale inhibition method was used to evaluate the scale inhibition performance of 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP). Autoclave static experiments were used to study the corrosion inhibition properties of the main material for industrial boilers (20# carbon steel) with an HEDP additive in the industrial boiler water medium. The electrochemical behavior of HEDP on carbon steel corrosion control was investigated using electrochemical impedance spectroscopy and Tafel polarization techniques. Experimental results indicate that HEDP can have a good scale inhibition effect when added at a quantity of 5 to 7 mg/L at a test temperature of not more than 100 °C. To achieve a high scale inhibition rate, the HEDP dosage must be increased when the test temperature exceeds 100 °C. Electrochemical and autoclave static experimental results suggest that HEDP has a good corrosion inhibition effect on 20# carbon steel at a concentration of 25 mg/L. HEDP is an excellent water treatment agent.

  11. Adsorption thermodynamics of Methylene Blue onto bentonite.

    PubMed

    Hong, Song; Wen, Cheng; He, Jing; Gan, Fuxing; Ho, Yuh-Shan

    2009-08-15

    The effect of temperature on the equilibrium adsorption of Methylene Blue dye from aqueous solution using bentonite was investigated. The equilibrium adsorption data were analyzed using three widely applied isotherms: Langmuir, Freundlich, and Redlich-Peterson. A non-linear method was used for comparing the best fit of the isotherms. Best fit was found to be Redlich-Peterson isotherm. Thermodynamic parameters, such as DeltaG degrees, DeltaH degrees, and DeltaS degrees were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. Results suggested that the Methylene Blue adsorption on bentonite was a spontaneous and endothermic process.

  12. Severe anaphylactic shock with methylene blue instillation.

    PubMed

    Dewachter, Pascale; Mouton-Faivre, Claudie; Tréchot, Philippe; Lleu, Jean-Claude; Mertes, Paul Michel

    2005-07-01

    We report a documented severe immunoglobulin E-mediated hypersensitivity reaction associated with use of 1% methylene blue for detection of tubal permeability occurring during general anesthesia. Clinical symptoms, biological assessment results, and cutaneous test positivity confirmed an anaphylactic reaction to methylene blue. This case report confirms the need for systematic allergological investigation of all drugs and substances administered during the perioperative period in the event of a hypersensitivity reaction occurring during anesthesia. Anesthesiologists should be aware of the possibility of hypersensitivity reactions involving any drug or substance used during surgery.

  13. Methylene Blue Causing Serotonin Syndrome Following Cystocele Repair.

    PubMed

    Kapadia, Kailash; Cheung, Felix; Lee, Wai; Thalappillil, Richard; Florence, F Barry; Kim, Jason

    2016-11-01

    Methylene blue is an intravenously administered agent that may potentiate serotonin syndrome. The usage of methylene blue to evaluate ureters for injuries and patency during urological surgeries is recognized as common practice. However, there is no mention of serotonin syndrome caused by methylene blue in urological literature or for urological surgery. We report the first urological case in order to raise awareness of the risk for serotonin toxicity with utilizing methylene blue. PMID:27617215

  14. Number of Oxidations Relative to Methylene.

    ERIC Educational Resources Information Center

    Kjonaas, Richard A.

    1986-01-01

    Describes a new way of quantifying organic oxidation-reduction reactions that extends the traditional method of assigning oxidation numbers by replacing them with NORM's (Number of Oxidations Relative to Methylene). This modification allows the system to be applied to more complex examples without the cumbersomeness inherent in the original…

  15. Two new supramolecular metal diphosphonates: Synthesis, characterization, crystal structure and inhibiting effects on metallic corrosion

    NASA Astrophysics Data System (ADS)

    Gholivand, Khodayar; Yaghoubi, Rouhollah; Farrokhi, Alireza; Khoddami, Shahram

    2016-11-01

    Two new divalent metal(II) aminodiphosphonates with layered structure, namely, Cu(H3L1)2·2H2O (1), [H4L1=methyl-N(CH2PO3H2)2] and Cd2(H2L2)4(2), [H4L2=n-propyl-N(CH2PO3H2)2] were synthesized and characterized. The Cu(II) ions in complex 1 are octahedrally coordinated by four oxygen atoms from two chelating ligands and two phosphonate oxygen atoms from two neighboring Cu(H3L1)2 units. The Cu(H3L1)2 units are interconnected by bridging phosphonate groups, forming a 2-D metal phosphonate layer. The structure of complex 2 contains two unique Cd(II) ions octahedrally-coordinated by six phosphonate oxygen atoms from four H2L2 diphosphonate anions. Corrosion inhibition performances of 1 and 2 were also compared with each other in order to study the effect of combinations of externally added Cd/H4L2 and Cu/H4L1 (1:1 ratio) on corrosion rates of carbon steel. It was found that at pH 3.0, Cd/H4L2 or Cu/H4L1 combinations do not have noticeable corrosion inhibition efficiency for carbon steel. In contrast, at pH 7.0, higher corrosion inhibition efficiency was achieved for Cd/H4L2. Physical characterizations such as scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) were applied to study the corrosion specimens and film material.

  16. Modification of Hydroxyapatite with Ion-Selective Complexants: 1-Hydroxyethane-1,1-diphosphonic Acid

    PubMed Central

    2015-01-01

    Hydroxyapatite (HAP) was modified with 1-hydroxyethane-1,1-diphosphonic acid (HEDP), and its effect on divalent metal ion binding was determined. HAP was synthesized from calcium hydroxide and phosphoric acid. After calcination, it was modified with HEDP, and the influence of time and temperature on the modification was investigated. HEDP incorporation increased as its initial solution concentration increased from 0.01 to 0.50 M. Unmodified and modified HAP were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and specific surface area analysis. Ca/P ratios, acid capacities, and phosphorus elemental analyses gave the effect of modification on composition and surface characteristics. A high reaction temperature produced new phosphonate bands at 993, 1082, and 1144 cm–1 that indicated the presence of HEDP. HAP modification at a high temperature–long reaction time had the highest HEDP loading and gave the sharpest XRD peaks. The emergence of new HAP–HEDP strands was observed in SEM images for treated samples while EDS showed high phosphorus contents in these strands. Modified HAP had a high acid capacity from the additional P–OH groups in HEDP. The P(O)OH groups maintain their ability to bind metal ions within the HAP matrix: contacting the modified HAP with 10–4 N nitrate solutions of five transition metal ions gives an affinity sequence of Pb(II) > Cd(II) > Zn(II) > Ni(II) > Cu(II). This result is comparable to that of commercially available di(2-ethylhexyl)phosphoric acid, a common solvent extractant, and the trend is consistent with the Misono softness parameter of metal ion polarizabilities. PMID:25678741

  17. N-heterocyclic amine-directed structures and properties of two Cu(II) diphosphonates.

    PubMed

    Ma, Kui-Rong; Ma, Feng; Zhu, Yu-Lan; Yu, Lin-Juan; Zhao, Xiao-Min; Yang, Yin; Duan, Wei-He

    2011-10-14

    By introducing the second organic N-heterocyclic ligands 4'-(4-pyridyl)-4,2':6',4''-terpyridine (pyterpy) and 4,4'-bipyridyl (4,4'-bipy), two examples of Cu(II)-diphosphonates, [Cu(3)(HL)(2)(Hpyterpy)(2)]·2H(2)O 1 and [Cu(4)(HL)(2)(4,4'-bipy)(H(2)O)(5)] 2 based on 1-hydroxyethylidenediphosphonic acid (H(5)L = CH(3)C(OH)(PO(3)H(2))(2)), have been hydrothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions reveal that compound 1 has a one-dimensional fishbone-like chain constructed by anions [Cu(3)(HL)(2)(2-)](n) while simultaneously organic cations [Hpyterpy(+)](n) suspending both sides, and compound 2 exhibits two-dimensional inorganic-organic alternate arrangement layer built from 1-D ladder-like inorganic chain with tetranuclear cluster [Cu(4)O(10)] via 4,4'-bipy linkage. The results of electrochemical measurements indicate half-wave potential of 1 (E(1/2)(1) = 1.01 V) is less than that of 2 (E(1/2)(2) = 1.20 V), indicating a good D-A system in ICT for 1. Moreover fluorescent measurements reveal that emission intensity of 1 centered at 422 nm is larger than that of 2 emitted at 420 nm, caused by intraligand π*-π emission state of organic N-heterocyclic amine (λ(ex) = 233 nm). Magnetism data indicate that compound 1 exhibits ferrimagnetic interactions between metal centers, while compound 2 has antiferromagnetic property.

  18. Featured Molecules: Ascorbic Acid and Methylene Blue

    NASA Astrophysics Data System (ADS)

    Coleman, William F.; Wildman, Randall J.

    2003-05-01

    The WebWare molecules of the month for May are featured in several articles in this issue. "Arsenic: Not So Evil After All?" discusses the pharmaceutical uses of methylene blue and its development as the first synthetic drug used against a specific disease. The JCE Classroom Activity "Out of the Blue" and the article "Greening the Blue Bottle" feature methylene blue and ascorbic acid as two key ingredients in the formulation of the blue bottle. You can also see a colorful example of these two molecules in action on the cover. "Sailing on the 'C': A Vitamin Titration with a Twist" describes an experiment to determine the vitamin C (ascorbic acid) content of citrus fruits and challenges students, as eighteenth-century sea captains, to decide the best fruit to take on a long voyage. Fully manipulable (Chime) versions of these and other molecules are available at Only@JCE Online.

  19. Use of diphosphonates to correct disorders in calcium metabolism and mineral composition of bone tissue with 60-day hypokinesia in rats

    NASA Technical Reports Server (NTRS)

    Morukov, B. V.; Zaychik, V. YE.; Ivanov, V. M.; Orlov, O. I.

    1988-01-01

    Compounds of the diphosphonate group suppress bone resorption and bone tissue metabolism, from which it was assumed that they can be used for the prevention of osteoporosis and disorders of calcium homeostasis in humans during space flight. Two compounds of this group were used for preventive purposes in 60 day hypokinesia in rats. The results showed that diphosphonates have a marked effect on calcium metabolism and the condition of the bone tissues under conditions of long term hypokinesia: they reduce the content of ionized calcium in blood, delay the loss of calcium and phosphorus by the bone tissue, and to a considerable degree prevent reduction of bone density. This confirms the possibility of using compounds of this group for correcting and preventing changes of bone tissue and mineral metabolism during long term hypokinesia.

  20. Methylene Blue Inhibits Caspases by Oxidation of the Catalytic Cysteine.

    PubMed

    Pakavathkumar, Prateep; Sharma, Gyanesh; Kaushal, Vikas; Foveau, Bénédicte; LeBlanc, Andrea C

    2015-09-24

    Methylene blue, currently in phase 3 clinical trials against Alzheimer Disease, disaggregates the Tau protein of neurofibrillary tangles by oxidizing specific cysteine residues. Here, we investigated if methylene blue can inhibit caspases via the oxidation of their active site cysteine. Methylene blue, and derivatives, azure A and azure B competitively inhibited recombinant Caspase-6 (Casp6), and inhibited Casp6 activity in transfected human colon carcinoma cells and in serum-deprived primary human neuron cultures. Methylene blue also inhibited recombinant Casp1 and Casp3. Furthermore, methylene blue inhibited Casp3 activity in an acute mouse model of liver toxicity. Mass spectrometry confirmed methylene blue and azure B oxidation of the catalytic Cys163 cysteine of Casp6. Together, these results show a novel inhibitory mechanism of caspases via sulfenation of the active site cysteine. These results indicate that methylene blue or its derivatives could (1) have an additional effect against Alzheimer Disease by inhibiting brain caspase activity, (2) be used as a drug to prevent caspase activation in other conditions, and (3) predispose chronically treated individuals to cancer via the inhibition of caspases.

  1. Methylene Blue Inhibits Caspases by Oxidation of the Catalytic Cysteine

    PubMed Central

    Pakavathkumar, Prateep; Sharma, Gyanesh; Kaushal, Vikas; Foveau, Bénédicte; LeBlanc, Andrea C.

    2015-01-01

    Methylene blue, currently in phase 3 clinical trials against Alzheimer Disease, disaggregates the Tau protein of neurofibrillary tangles by oxidizing specific cysteine residues. Here, we investigated if methylene blue can inhibit caspases via the oxidation of their active site cysteine. Methylene blue, and derivatives, azure A and azure B competitively inhibited recombinant Caspase-6 (Casp6), and inhibited Casp6 activity in transfected human colon carcinoma cells and in serum-deprived primary human neuron cultures. Methylene blue also inhibited recombinant Casp1 and Casp3. Furthermore, methylene blue inhibited Casp3 activity in an acute mouse model of liver toxicity. Mass spectrometry confirmed methylene blue and azure B oxidation of the catalytic Cys163 cysteine of Casp6. Together, these results show a novel inhibitory mechanism of caspases via sulfenation of the active site cysteine. These results indicate that methylene blue or its derivatives could (1) have an additional effect against Alzheimer Disease by inhibiting brain caspase activity, (2) be used as a drug to prevent caspase activation in other conditions, and (3) predispose chronically treated individuals to cancer via the inhibition of caspases. PMID:26400108

  2. Prophylaxis and reversal of ifosfamide encephalopathy with methylene-blue.

    PubMed

    Küpfer, A; Aeschlimann, C; Wermuth, B; Cerny, T

    1994-03-26

    The antineoplastic ifosfamide produces dose-dependent signs of neurotoxicity. After ifosfamide overdose in a patient, we found excessive urinary excretion of glutaric acid and sarcosine, which is compatible with glutaric aciduria type II, a defect in mitochondrial fatty acid oxidation that results from defective electron transfer to flavoproteins. We therefore used the electron-accepting drug methylene-blue as an antidote for ifosfamide encephalopathy. In one patient, ifosfamide neurotoxicity was rapidly reversed by methylene-blue 50 mg intravenously. In another patient with previous episodes of ifosfamide encephalopathy, methylene-blue was administered orally prophylactically. No symptoms of neurotoxicity were noted.

  3. 99mtc-Ubiquicidin [29–41], a Promising Radiopharmaceutical to Differentiate Orthopedic Implant Infections from Sterile Inflammation

    PubMed Central

    Beiki, Davood; Yousefi, Gholamali; Fallahi, Babak; Tahmasebi, Mohammad Naghi; Gholamrezanezhad, Ali; Fard-Esfahani, Armaghan; Erfani, Mostafa; Eftekhari, Mohammad

    2013-01-01

    Ubiquicidin (UBI) [29-41] is a synthetic cationic antimicrobial peptide that preferentially binds to bacterial cell membrane at the site of infection. We aimed to assess diagnostic value of 99mTc-UBI [29-41] as a radiopharmaceutical in differentiation of bacterial infection from sterile inflammation in suspected orthopedic implants. Nine patients suspected for orthopedic implant infection, all males with the mean age of 41.6 ± 20.9 years, were studied. A dose of 10 MBq/Kg (range : 555-740 MBq) 99mTc-UBI [29-41] was injected intravenously. A dynamic study followed by static whole body imaging at 30, 60 and 120 min post-radiotracer injection was acquired. Periprosthetic tissue culture was considered the closest test to a gold standard for diagnosing infections and scintigraphic scans were categorized as true- or false-positive and true- or false-negative, considering the bacterial culture as the gold standard. No adverse reaction was observed during or after the radiotracer injection days. There were five true positive, four true negative and no false positive and false negative scans. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were all calculated as 100%. We found a high diagnostic accuracy for 99mTc-UBI [29-41] scintigraphy in differentiation of bacterial infection from sterile inflammation in suspected orthopedic implants. Therefore, 99mTc-UBI [29-41] scintigraphy might be potentially recommended as a safe and promising imaging modality in these settings. However, further studies on a larger number of patients and different pathologies are still needed. PMID:24250609

  4. Thoracoscopic resection with intraoperative use of methylene blue to localize mediastinal parathyroid adenomas.

    PubMed

    Adachi, Yoshin; Nakamura, Hiroshige; Taniguchi, Yuji; Miwa, Ken; Fujioka, Shinji; Haruki, Tomohiro

    2012-03-01

    We report a case of thoracoscopic resection of mediastinal parathyroid adenomas using methylene blue to localize the tumors during the operation. After methylene blue 4 mg/kg was injected intravenously, we easily identified methylene blue-stained parathyroid glands and successfully resected them with sufficient surgical margins. The use of methylene blue for detection of parathyroid adenoma is a useful technique.

  5. Iodine-131-labeled diphosphonates for palliative treatment of bone metastases: II. Preliminary clinical results with iodine-131 BDP3

    SciTech Connect

    Eisenhut, M.; Berberich, R.; Kimmig, B.; Oberhausen, E.

    1986-08-01

    The kinetics, dosimetry, and response of iodine-131 alpha-amino-(4-hydroxybenzylidene)-diphosphonate ((/sup 131/I)BDP3) treatment were investigated with patients who had pain symptoms from bone metastases of various primary carcinoma. The blood clearance of (/sup 131/I)BDP3 was rapid. More than 90% disappeared from the blood pool at 2 hr after injection. The excretion of the activity occurred solely through the kidneys and mean total-body retention at 48 hr was 48.6%. The urinary activity showed a metabolite which must be formed by an in vivo cleavage reaction of a phosphorus-carbon bond. The uptake of in vivo cleaved (/sup 131/I)iodide in the unblocked thyroid was approximately 0.5%. The effective half-life of (/sup 131/I)BDP3 in metastatic bone (median 182 hr; range 177-205 hr) proved to be longer than in unaffected areas (145 hr; 140-165 hr). Palliative therapies were performed with 18 patients. They received doses ranging between 6 and 48 mCi (/sup 131/I)BDP3. The response was 44% complete pain relief, 6% substantial pain relief, 22% minimal improvement, and 28% no change. The duration of response ranged between 1 and 8 wk.

  6. [99mTc]diphosphonate uptake and hemodynamics in experimental arthritis: effect of naproxen in the canine carrageenan injection model.

    PubMed

    Hansen, E S; He, S Z; Søballe, K; Kjølseth, D; Henriksen, T B; Hjortdal, V E; Bünger, C

    1992-09-01

    The impact of naproxen treatment on juxta-articular hemodynamics and bone metabolism in experimental juvenile arthritis was studied in the articular carrageenan injection model. Unilateral gonarthritis was induced for 12 weeks in eight dogs receiving naproxen (dosage, 2 mg/kg) and eight controls. Regional blood flow was assessed by the microsphere method, plasma volume by the distribution space of [125I]fibrinogen, and bone metabolism by the 2-h uptake of [99mTc]diphosphonate ([99mTc]DPD). Synovial effusion was less prominent with naproxen treatment as judged by joint fluid volume and pressure. Naproxen reduced the arthritic capsular hyperemia, almost normalized a severe blood flow increase in patella and both juxta-articular epiphyses, ameliorated an expansion of plasma volume in the patella and the distal femoral epiphysis, and normalized an increased [99mTc]DPD uptake in subchondral femoral bone and the tibial cortex. Significantly increased arteriovenous shunting in the arthritic extremity was unaffected by naproxen. The study suggests that long-term cyclooxygenase inhibition offers protection against hemodynamic and metabolic changes in juxta-articular bone secondary to synovial inflammation. PMID:1500978

  7. Technetium-99m MDP vs technetium-99m dicarboxypropane diphosphonate. A clinical comparison in various pathologic conditions

    SciTech Connect

    Godart, G.; Durez, M.; Bevilacqua, M.; Abramovici, J.; Robience, Y.

    1986-02-01

    The performance of Tc-99m MDP vs Tc-99m dicarboxypropane diphosphonate (DPD) was evaluated in 20 patients with various skeletal bone diseases. Each patient was investigated twice, with an interval of three days between studies and using the same protocol, hence each case served as its own control. The results were: In a subjective interpretation by five independent and experienced investigators, the difference between agents was small, yet in favor of MDP. Region of interest (ROI) analysis of the pooled results in 74.4% of all cases shows a higher bone lesion to normal bone ratio (BL/NB), and in 79.3% of all cases, a better bone lesion to soft tissue ratio (BL/ST) with Tc-99m MDP. When considering pathology types separately, the BL/NB ratio of Tc-99m MDP was 17.7% higher than the one of Tc-99m DPD in metastases, 9.5% higher in rheumatoid arthritis, 2.8% higher in metabolic diseases, and 24% higher in bone fractures. Student's paired t test on the pooled BL/NB ratios shows a difference of 15.5% for Tc-99m MDP, significant at P = 0.00155. The overall results of our study favor Tc-99m MDP.

  8. Complexation of U(VI) with 1-Hydroxyethane-1,1-diphosphonicAcid (HEDPA) in Acidic to Basic Solutions

    SciTech Connect

    Reed, W A; Rao, L; Zanonato, P; Garnov, A; Powell, B A; Nash, K L

    2007-01-24

    Complexation of U(VI) with 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) in acidic to basic solutions has been studied with multiple techniques. A number of 1:1 (UO{sub 2}H{sub 3}L), 1:2 (UO{sub 2}H{sub j}L{sub 2} where j = 4, 3, 2, 1, 0 and -1) and 2:2 ((UO{sub 2}){sub 2}H{sub j}L{sub 2} where j = 1, 0 and -1) complexes form, but the 1:2 complexes are the major species in a wide pH range. Thermodynamic parameters (formation constants, enthalpy and entropy of complexation) were determined by potentiometry and calorimetry. Data indicate that the complexation of U(VI) with HEDPA is exothermic, favored by the enthalpy of complexation. This is in contrast to the complexation of U(VI) with dicarboxylic acids in which the enthalpy term usually is unfavorable. Results from electrospray ionization mass spectrometry (ESI-MS) and {sup 31}P NMR have confirmed the presence of 1:1, 1:2 and 2:2 U(VI)-HEDPA complexes.

  9. Self-assembled monolayers of alpha,omega-diphosphonic acids on Ti enable complete or spatially controlled surface derivatization.

    PubMed

    Danahy, Michael P; Avaltroni, Michael J; Midwood, Kim S; Schwarzbauer, Jean E; Schwartz, Jeffrey

    2004-06-22

    Alpha,omega-diphosphonic acids self-assemble on the native oxide surfaces of Ti or Ti-6Al-4V. Heating gives strongly bonded phosphonate monolayers. Infrared and X-ray spectroscopic and water contact angle data show that the films are bonded to the surface by one phosphonate unit; the other remains a phosphonic acid. Surface loadings were measured by quartz crystal microbalance procedures. Mechanical shear strengths for the films were also measured; these do not correlate simply with surface loadings. Films formed from 1,12-diphosphonododecane were treated with zirconium tetra(tert-butoxide) to give surface Zr complex species; derivatives of these surface complexes are stable to hydrolysis under physiological conditions and are mechanically strong. The complexation reaction can be accomplished over the entire surface; alternatively, dropwise application of the alkoxide to the surface enables spatial control of deposition. The cell attractive peptide derivative RGDC can be bound to these surface Zr alkoxide complexes through (maleimido)-alkylcarboxylate intermediates. Surfaces modified with RGDC were shown to be effective for osteoblast binding and proliferation. PMID:15986670

  10. Effect of ethane-I-hydroxy-I, I-diphosphonate on arterial calcinosis induced by hypervitaminosis D: a morphologic investigation.

    PubMed Central

    Kingma, J. G.; Roy, P. E.

    1990-01-01

    The present study was undertaken to examine changes in vascular ultrastructure of rats subjected to hypervitaminosis D with or without treatment with ethane-I-hydroxy-I, I-diphosphonate (EHDP). Five groups of rats were studied. Untreated rats were given 0.9% NaCl i.p. Sham-treated rats were given vehicle (corn oil). Treated rats were given ergocalciferol (75,000 IU i.p.) dissolved in vehicle with or without EHDP (5 mM/100 g body-weight i.p.). Rats which had been given ergocalciferol without EHDP developed hypercalcemia and demonstrated significant arterial calcinosis. A similar degree of calcinosis was not observed in rats given ergocalciferol with EHDP. EHDP appeared to inhibit arterial calcinosis; however, it did not affect plasma calcium levels. This suggests that EHDP might delay calcium influx into the cell and thereby prevent calcium overload. Our findings support the suggestion that EHDP therapy can be an effective treatment for the inhibition of dystrophic arterial calcinosis. Images Fig. 2 Fig. 3 Fig. 4 PMID:2109995

  11. Paradoxical acute hypercalcemic effect of salmon calcitonin in patients having Paget's disease of bone after treatment with dichloromethylene diphosphonate.

    PubMed

    Delmas, P D; Chapuy, M C; Meunier, P J

    1984-05-01

    The hypocalcemia following administration of calcitonin may be an index to disease activity in Paget's disease of bone. Therefore, we assessed the effect of a single injection of 100 MRC units of salmon calcitonin (SCT) on plasma calcium in 28 patients with active Paget's disease before and after 6 months of treatment with dichloromethylene diphosphonate (Cl2MDP) at a dose of 400 mg/day (3 patients), 800 mg/day (8 patients), 1.600 mg/day (9 patients) or 2.600 mg/day (8 patients). The mean SCT-induced hypocalcemia was reduced by Cl2MDP and there was a significant positive correlation between the decrease of serum calcium induced by SCT and bone resorption evaluated by the number of osteoclasts on bone biopsy taken in pagetic iliac crest. After Cl2MCP treatment, 5 patients manifested a paradoxical hypercalcemic response to SCT injection ranging from +0.3 mg/dl to +0.5 mg/dl, which was sustained over the 9 hours following injection. As these patients had a dramatic inhibition of bone resorption induced by Cl2 MDP, it is suggested that the hypercalcemic response to SCT might reflect persistence or exaggeration of the early hypercalcemic effect of CT which reportedly precedes the hypocalcemic response to SCT. PMID:6234216

  12. Effect of 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) on Partitioning of Np and Pu to Synthetic Boehmite

    SciTech Connect

    Powell, Brian A.; Rao, Linfeng; Nash, Kenneth L.

    2009-05-01

    The effect of 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) on sorption of Np(V) and Pu(V) to synthetic boehmite ({gamma}-AlOOH) was examined a function of time and pH (between 4 to 11). Sorption of both elements in boehmite suspensions (1 M NaCl, 600 mg L{sup -1} boehmite) increased with increasing pH. Sorption edges for neptunium and plutonium occurred at approximately pH 8.0 and 6.6, respectively. After steady state partitioning was reached, HEDPA was added to the neptunium-boehmite and plutonium-boehmite suspensions. Neptunium and plutonium partitioning appears to be primarily affected by the formation of soluble Np:HEDPA and Pu:HEDPA complexes, the dissolution of boehmite promoted by HEDPA, and the precipitation of Np:HEDPA and Pu:HEDPA colloids. The results are discussed in terms of applicability of HEDPA-promoted dissolution as a waste reduction method in the treatment of sludge phases contained within high-level nuclear waste storage tanks.

  13. Methylene blue treatment in experimental ischemic stroke: a mini review

    PubMed Central

    Jiang, Zhao; Duong, Timothy Q

    2016-01-01

    Stroke is a leading cause of death and long-term disability. Methylene blue, a drug grandfathered by the Food and Drug Administration with a long history of safe usage in humans for treating methemoglobinemia and cyanide poisoning, has recently been shown to be neuroprotective in neurodegenerative diseases and brain injuries. The goal of this paper is to review studies on methylene blue in experimental stroke models. PMID:27042692

  14. Neurometabolic mechanisms for memory enhancement and neuroprotection of methylene blue

    PubMed Central

    Rojas, Julio C.; Bruchey, Aleksandra K.; Gonzalez-Lima, F.

    2011-01-01

    This paper provides the first review of the memory-enhancing and neuroprotective metabolic mechanisms of action of methylene blue in vivo. These mechanisms have important implications as a new neurobiological approach to improve normal memory and to treat memory impairment and neurodegeneration associated with mitochondrial dysfunction. Methylene blue’s action is unique because its neurobiological effects are not determined by regular drug-receptor interactions or drug-response paradigms. Methylene blue shows a hormetic dose-response, with opposite effects at low and high doses. At low doses, methylene blue is an electron cycler in the mitochondrial electron transport chain, with unparalleled antioxidant and cell respiration-enhancing properties that affect the function of the nervous system in a versatile manner. A major role of the respiratory enzyme cytochrome oxidase on the memory-enhancing effects of methylene blue is supported by available data. The memory-enhancing effects have been associated with improvement of memory consolidation in a network-specific and use-dependent fashion. In addition, low doses of methylene blue have also been used for neuroprotection against mitochondrial dysfunction in humans and experimental models of disease. The unique auto-oxidizing property of methylene blue and its pleiotropic effects on a number of tissue oxidases explain its potent neuroprotective effects at low doses. The evidence reviewed supports a mechanistic role of low-dose methylene blue as a promising and safe intervention for improving memory and for the treatment of acute and chronic conditions characterized by increased oxidative stress, neurodegeneration and memory impairment. PMID:22067440

  15. Fate and effects of methylene chloride in activated sludge.

    PubMed Central

    Klecka, G M

    1982-01-01

    Activated sludge obtained from a municipal wastewater treatment plant was acclimated to methylene chloride at concentrations between 1 and 100 mg/liter by continuous exposure to the compound for 9 to 11 days. Acclimated cultures were shown to mineralize methylene chloride to carbon dioxide and chloride. Rates of methylene chloride degradation were 0.14, 2.3, and 7.4 mg of CH2Cl2 consumed per h per g of mixed-liquor suspended solids for cultures incubated in the presence of 1, 10, and 100 mg/liter, respectively. Concentrations of methylene chloride between 10 and 1,000 mg/liter had no significant effect on O2 consumption or glucose metabolism by activated sludge. A hypothetical model was developed to examine the significance of volatilization and biodegradation for the removal of methylene chloride from an activated sludge reactor. Application of the model indicated that the rate of biodegradation was approximately 12 times greater than the rate of volatilization. Thus, biodegradation may be the predominant process determining the fate of methylene chloride in activated sludge systems continuously exposed to the compound. PMID:7138008

  16. Treatment of methylene-induced carbon monoxide poisoning with hyperbaric oxygenation. Final report

    SciTech Connect

    Rudge, F.W.

    1989-01-01

    Methylene chloride is an organic solvent with many industrial uses. Inhalation of methylene chloride fumes can result in toxicity, caused by hepatic biotransformation of methylene chloride to carbon monoxide. A case of acute methylene chloride poisoning is presented, including successful treatment of this patient with the use of hyperbaric oxygenation. The rationale for the use of hyperbaric oxygenation in the treatment of methylene chloride poisoning is discussed. (aw)

  17. Further examples of the failure of surrogates to properly model the structural and hydrothermal chemistry of transuranium elements: Insights provided by uranium and neptunium diphosphonates

    SciTech Connect

    Nelson, Anna-Gay D; Bray, Travis H; Zhang, Wei; Haire, Richard G.; Sayler, Todd S.; Albrecht-Schmitt, Thomas E

    2008-01-01

    In situ hydrothermal reduction of Np(VI) to Np(IV) in the presence of methylenediphosphonic acid (C1P2) results in the crystallization of Np[CH2(PO3)2](H2O)2 (NpC1P2-1). Similar reactions have been explored with U(VI) resulting in the isolation of the U(IV) diphosphonate U[CH2(PO3)2](H2O) (UC1P2-1), and the two U(VI) diphosphonates (UO2)2[CH2(PO3)2](H2O)3 H2O (UC1P2-2) and UO2[CH2(PO3H)2](H2O) (UC1P2-3). Single crystal diffraction studies of NpC1P2-1 reveal that it consists of eight-coordinate Np(IV) bound by diphosphonate anions and two coordinating water molecules to create a polar three-dimensional framework structure wherein the water molecules reside in channels. The structure of UC1P2-1 is similar to that of NpC1P2-1 in that it also adopts a three-dimensional structure. However, the U(IV) centers are seven-coordinate with only a single bound water molecule. UC1P2-2 and UC1P2-3 both contain U(VI). Nevertheless, their structures are quite distinct with UC1P2-2 being composed of corrugated layers containing UO6 and UO7 units bridged by C1P2; whereas, UC1P2-3 is found as a polar three-dimensional network structure containing only pentagonal bipyramidal U(VI). Fluorescence measurements on UC1P2-2 and UC1P2-3 exhibit emission from the uranyl moieties with classical vibronic fine-structure.

  18. Adsorption of methylene blue from aqueous solution by graphene.

    PubMed

    Liu, Tonghao; Li, Yanhui; Du, Qiuju; Sun, Jiankun; Jiao, Yuqin; Yang, Guangming; Wang, Zonghua; Xia, Yanzhi; Zhang, Wei; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai

    2012-02-01

    Graphene was prepared using a modified Hummers' method. The physico-chemical properties of graphene were characterized by TEM, BET specific surface area, FTIR, Raman and XRD measurements. The effect factors including pH, contact time, temperature and dosage on the adsorption properties of methylene blue onto graphene were investigated. The experimental data of isotherm followed the Langmuir isotherm model better than the Freundlich model. The maximum adsorption capacity obtained from Langmuir isotherm equation at 293 K was 153.85 mg/g, indicating graphene is a good adsorbent for the adsorption of MB. The kinetic study illustrated that the adsorption of methylene blue onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of methylene blue onto graphene was an endothermic and spontaneous process.

  19. Technetium-99m methylene diphosphonate uptake in the brachialis muscle hematoma in a patient with prostate cancer and coagulation disorder mimicking bone metastasis evaluated by single-photon emission tomography-computed tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshakh; Madhavan, Devdas; Shinto, Ajit Sugunan

    2013-10-01

    We report a case of 79-year-old male with prostate cancer and coagulation disorder presented with left shoulder pain. He underwent bone scintigraphy to rule out metastasis, which showed intense foci of tracer activity in the left axilla. Hybrid single-photon emission tomography-computed tomography (SPECT/CT) of the shoulder region localized tracer uptake to the left brachialis muscle hematoma.

  20. Technetium-99m methylene diphosphonate uptake in the brachialis muscle hematoma in a patient with prostate cancer and coagulation disorder mimicking bone metastasis evaluated by single-photon emission tomography-computed tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshakh; Madhavan, Devdas; Shinto, Ajit Sugunan

    2013-01-01

    We report a case of 79-year-old male with prostate cancer and coagulation disorder presented with left shoulder pain. He underwent bone scintigraphy to rule out metastasis, which showed intense foci of tracer activity in the left axilla. Hybrid single-photon emission tomography-computed tomography (SPECT/CT) of the shoulder region localized tracer uptake to the left brachialis muscle hematoma. PMID:24379534

  1. Methylene Diphenyl Diisocyanate (monomeric MDI) and polymeric MDI (PMDI)

    Integrated Risk Information System (IRIS)

    TOXICOLOGICAL REVIEW of METHYLENE DIPHENYL DIISOCYANATE ( MDI ) ( CAS No . 101 - 68 - 8 and 9016 - 87 - 9 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) February 1998 U.S . ENVIRONMENTAL PROTECTION AGENCY WASHINGTON , DC TABLE OF CONTENTS TOXICOLOGICAL REVIEW

  2. 4,4\\'-Methylene bis(N,N\\'-dimethyl)aniline

    Integrated Risk Information System (IRIS)

    4,4 ' - Methylene bis ( N , N ' - dimethyl ) aniline ; CASRN 101 - 61 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Haz

  3. Extinction Memory Improvement by the Metabolic Enhancer Methylene Blue

    ERIC Educational Resources Information Center

    Gonzalez-Lima, F.; Bruchey, Aleksandra K.

    2004-01-01

    We investigated whether postextinction administration of methylene blue (MB) could enhance retention of an extinguished conditioned response. MB is a redox compound that at low doses elevates cytochrome oxidase activity, thereby improving brain energy production. Saline or MB (4 mg/kg intraperitoneally) were administered to rats for 5 d following…

  4. Methylene Blue-Ascorbic Acid: An Undergraduate Experiment in Kinetics.

    ERIC Educational Resources Information Center

    Snehalatha, K. C.; And Others

    1997-01-01

    Describes a laboratory exercise involving methylene blue and L-ascorbic acid in a simple clock reaction technique to illustrate the basic concepts of chemical kinetics. If stock solutions are supplied and each type of experiment takes no more than half an hour, the entire investigation can be completed in three practical sessions of three hours…

  5. Borax methylene blue: a spectroscopic and staining study.

    PubMed

    Donaldson, P T; Russo, A; Reynolds, C; Lillie, R D

    1978-07-01

    Borax methylene blue is quite stable at room temperatures of 22-25 C. At 30 C polychroming is slow; during 50 days in a water bath at this temperature the absorption peak moves from 665 to 656 nm. At 35 C, the absorption peak reaches 660 nm in 7 days, 654 nm in 14. At 60 C polychroming is rapid, the absorption peak reaching 640-620 nm in 3 days. When the pH of the borax methylene blue solutions, normally about 9.0, is adjusted to pH 6.5, the absorption peak remains at 665 nm even when incubated at 60 C for extended periods. When used as a blood stain 0.4 ml borax methylene blue (1% methylene blue in 1% borax), 4 ml acetone, 2 ml borax-acid phosphate buffer to bring the solution to pH 6.5, and distilled water to make 40 ml, with 0.2 ml 1% eosin added just before using, an excellent Nocht-Giemsa type stain is achieved after 30 minutes staining. The material plasmodia P. falciparum, P. vivax, and P. berghei stain moderate blue with dark red chromatin and green to black pigment granules. The study confirms Malachowski's 1891 results and explains Gautier's 1896-98 failure to duplicate it.

  6. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Methylene blue-containing drugs for use in animals... Decisions § 500.27 Methylene blue-containing drugs for use in animals. (a) New information requires a re- evaluation of the status of drugs containing methylene blue (tetramethylthionine chloride) for oral use...

  7. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Methylene blue-containing drugs for use in animals... Decisions § 500.27 Methylene blue-containing drugs for use in animals. (a) New information requires a re- evaluation of the status of drugs containing methylene blue (tetramethylthionine chloride) for oral use...

  8. Methylene blue adsorption on graphene oxide/calcium alginate composites.

    PubMed

    Li, Yanhui; Du, Qiuju; Liu, Tonghao; Sun, Jiankun; Wang, Yonghao; Wu, Shaoling; Wang, Zonghua; Xia, Yanzhi; Xia, Linhua

    2013-06-01

    Graphene oxide has been used as an adsorbent in wastewater treatment. However, the dispersibility in aqueous solution and the biotoxicity to human cells of graphene oxide limits its practical application in environmental protection. In this research, a novel environmental friendly adsorbent, calcium alginate immobilized graphene oxide composites was prepared. The effects of pH, contact time, temperature and dosage on the adsorption properties of methylene blue onto calcium alginate immobilized graphene oxide composites were investigated. The equilibrium adsorption data were described by the Langmuir and Freundlich isotherms. The maximum adsorption capacity obtained from Langmuir isotherm equation was 181.81 mg/g. The pseudo-first order, pseudo-second order, and intraparticle diffusion equation were used to evaluate the kinetic data. Thermodynamic analysis of equilibriums indicated that the adsorption reaction of methylene blue onto calcium alginate immobilized graphene oxide composites was exothermic and spontaneous in nature.

  9. [Adsorption of methylene blue from water by the biochars generated from crop residues].

    PubMed

    Xu, Ren-Kou; Zhao, An-Zhen; Xiao, Shuang-Cheng; Yuan, Jin-Hua

    2012-01-01

    Biochars were prepared from straws of rice, peanut and soybean and rice hull using a low temperature pyrolysis method and adsorption of methylene blue by these biochars were investigated with batch and leaching experiments. Results indicated that biochars have high adsorption capacity for methylene blue and followed the order: rice straw char > soybean straw char > peanut straw char > rice hull char. This order is generally consistent with the amount of negative charge and specific surface area of these biochars. While methylene blue was mainly adsorbed specifically by the biochars, because the adsorption of methylene blue increased with the increase of ionic strength and the adsorption led to the shift of zeta potential of biochar particles to positive value direction. Langmuir equation fitted the adsorption isotherms well and can be used to describe the adsorption behaviors of methylene blue by the biochars. The maximum adsorption capacity of methylene blue predicted by langmuir equation was 196.1, 169.5, 129.9 and 89.3 mmol x kg(-1) for rice straw char, soybean straw char, peanut straw char and rice hull char, respectively. Leaching experiments show that rice hull char of 156 g can remove methylene blue from 30 L water containing 0.3 mmol x L(-1) of methylene blue completely and the cumulative amount of methylene blue absorbed by the biochar reaches 57.7 mmol x kg(-1). The biochars can be used as efficient adsorbents to remove methylene blue from waste water of dye.

  10. [Adsorption of methylene blue from water by the biochars generated from crop residues].

    PubMed

    Xu, Ren-Kou; Zhao, An-Zhen; Xiao, Shuang-Cheng; Yuan, Jin-Hua

    2012-01-01

    Biochars were prepared from straws of rice, peanut and soybean and rice hull using a low temperature pyrolysis method and adsorption of methylene blue by these biochars were investigated with batch and leaching experiments. Results indicated that biochars have high adsorption capacity for methylene blue and followed the order: rice straw char > soybean straw char > peanut straw char > rice hull char. This order is generally consistent with the amount of negative charge and specific surface area of these biochars. While methylene blue was mainly adsorbed specifically by the biochars, because the adsorption of methylene blue increased with the increase of ionic strength and the adsorption led to the shift of zeta potential of biochar particles to positive value direction. Langmuir equation fitted the adsorption isotherms well and can be used to describe the adsorption behaviors of methylene blue by the biochars. The maximum adsorption capacity of methylene blue predicted by langmuir equation was 196.1, 169.5, 129.9 and 89.3 mmol x kg(-1) for rice straw char, soybean straw char, peanut straw char and rice hull char, respectively. Leaching experiments show that rice hull char of 156 g can remove methylene blue from 30 L water containing 0.3 mmol x L(-1) of methylene blue completely and the cumulative amount of methylene blue absorbed by the biochar reaches 57.7 mmol x kg(-1). The biochars can be used as efficient adsorbents to remove methylene blue from waste water of dye. PMID:22452202

  11. Toxicology and metabolism of methylene chloride. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1993-06-01

    The bibliography contains citations concerning methylene chloride, its effects on biological systems, and its metabolic fate. Both animal and human studies, and case reports are examined for methylene chloride toxicity. Exposure to the chemical through inhalation, ingestion, and contact is examined. Occupational exposure to methylene chloride is included, and risk factors are discussed. Long term carcinogenicity of methylene chloride is also considered. Toxicity of other chlorinated organic compounds is referenced in related bibliographies. (Contains a minimum of 78 citations and includes a subject term index and title list.)

  12. Removal of methylene blue from dye effluent using ageratum conyzoide leaf powder (ACLP)

    NASA Astrophysics Data System (ADS)

    Ezechi, Ezerie Henry; Kutty, Shamsul Rahman bin Mohamed; Malakahmad, Amirhossein; Isa, Mohamed Hasnain; Aminu, Nasiru; Salihi, Ibrahim Umar

    2015-07-01

    Methylene blue (MB), a common environmental pollutant discharged from dye effluents were removed from synthetic effluents in this study using ageratum conyzoide leaf powder. Effects of operating parameters such as pH, initial Methylene blue concentration, adsorbent weight and contact time were examined on methylene blue removal whereas stirring speed was constant at 100 rpm. Results show that low pH (3-4) had more Methylene blue removal than high pH. Methylene blue removal decreased when initial concentration was increased but increased when adsorbent weight was increased. Removal of Methylene blue by Ageratum conyzoide leaf powder was rapid and significantly above 80% in all initial concentrations examined. At optimum conditions of pH 3, 20 minutes contact time and adsorbent weight of 60 mg for Methylene blue initial concentration of 20 mg/L, 40 mg/L and 60 mg/L, Methylene blue removal of 84.7%, 83.9% and 81.2% were obtained respectively. Results suggest that Ageratum conyzoide leaf powder could be potential adsorbents for Methylene blue removal from dye effluents.

  13. A Reminder of Methylene Blue's Effectiveness in Treating Vasoplegic Syndrome after On-Pump Cardiac Surgery.

    PubMed

    Manghelli, Joshua; Brown, Lisa; Tadros, Hany B; Munfakh, Nabil A

    2015-10-01

    The inflammatory response induced by cardiopulmonary bypass decreases vascular tone, which in turn can lead to vasoplegic syndrome. Indeed the hypotension consequent to on-pump cardiac surgery often necessitates vasopressor and intravenous fluid support. Methylene blue counteracts vasoplegic syndrome by inhibiting the formation of nitric oxide. We report the use of methylene blue in a 75-year-old man who developed vasoplegic syndrome after cardiac surgery. After the administration of methylene blue, his hypotension improved to the extent that he could be weaned from vasopressors. The use of methylene blue should be considered in patients who develop hypotension refractory to standard treatment after cardiac surgery. PMID:26504450

  14. Aminothienopyridazines and Methylene Blue Affect Tau Fibrillization via Cysteine Oxidation*

    PubMed Central

    Crowe, Alex; James, Michael J.; Lee, Virginia M.-Y.; Smith, Amos B.; Trojanowski, John Q.; Ballatore, Carlo; Brunden, Kurt R.

    2013-01-01

    Alzheimer disease and several other neurodegenerative disorders are characterized by the accumulation of intraneuronal fibrils comprised of the protein Tau. Tau is normally a soluble protein that stabilizes microtubules, with splice isoforms that contain either three (3-R) or four (4-R) microtubule binding repeats. The formation of Tau fibrils is thought to result in neuronal damage, and inhibitors of Tau fibrillization may hold promise as therapeutic agents. The process of Tau fibrillization can be replicated in vitro, and a number of small molecules have been identified that inhibit Tau fibril formation. However, little is known about how these molecules affect Tau fibrillization. Here, we examined the mechanism by which the previously described aminothieno pyridazine (ATPZ) series of compounds inhibit Tau fibrillization. Active ATPZs were found to promote the oxidation of the two cysteine residues within 4-R Tau by a redox cycling mechanism, resulting in the formation of a disulfide-containing compact monomer that was refractory to fibrillization. Moreover, the ATPZs facilitated intermolecular disulfide formation between 3-R Tau monomers, leading to dimers that were capable of fibrillization. The ATPZs also caused cysteine oxidation in molecules unrelated to Tau. Interestingly, methylene blue, an inhibitor of Tau fibrillization under evaluation in Alzheimer disease clinical trials, caused a similar oxidation of cysteines in Tau and other molecules. These findings reveal that the ATPZs and methylene blue act by a mechanism that may affect their viability as potential therapeutic agents. PMID:23443659

  15. Adsorption behavior of methylene blue on carbon nanotubes.

    PubMed

    Yao, Yunjin; Xu, Feifei; Chen, Ming; Xu, Zhongxiao; Zhu, Zhiwen

    2010-05-01

    The effect of temperature on the equilibrium adsorption of methylene blue dye from aqueous solution using carbon nanotubes was investigated. The equilibrium adsorption data were analyzed using two widely applied isotherms: Langmuir and Freundlich. The results revealed that Langmuir isotherm fit the experimental results well. Kinetic analyses were conducted using pseudo-first and second-order models and the intraparticle diffusion model. The regression results showed that the adsorption kinetics were more accurately represented by pseudo-second-order model. The activation energy of system (Ea) was calculated as 18.54 kJ/mol. Standard free energy changes (DeltaG(0)), standard enthalpy change (DeltaH(0)), and standard entropy change (DeltaS(0)) were calculated using adsorption equilibrium constants obtained from the Langmuir isotherm at different temperatures. All DeltaG(0) values were negative; the DeltaH(0) values and DeltaS(0) values of CNTs were 7.29 kJ/mol and 64.6 J/mol K, respectively. Results suggested that the methylene blue adsorption on CNTs was a spontaneous and endothermic process.

  16. Photobiological properties of positively charged methylene violet analogs.

    PubMed

    Houghtaling, M A; Perera, R; Owen, K E; Wagner, S; Kuhn, R J; Morrison, H

    2000-01-01

    O-Methyl methylene violet (OMeMV), O-methyl bromomethylene violet (OMeBrMV) and O-methyl iodomethylene violet (OMeIMV) have been prepared in order to test their potential utility as anti-viral and anti-tumor phototoxic dyes. Rates of photosensitized toxicity of KB cells with 633 nm irradiation are (x 10(-19) photon-1): 2.4, 2.2, 1.9 and 0.17 for OMeIMV, OMeBrMV, methylene violet (MV) and OMeMV, respectively. Rates of photosensitized inactivation of Sindbis virus in phosphate-buffered saline with 633 nm irradiation are (x 10(-18) photon-1): 3.3, 1.8, 0.99, 0.15 for MV, OMeIMV, OMeBrMV and OMeMV, respectively. Quantum efficiencies for singlet oxygen formation were determined as OMeIMV, 0.64; OMeBrMV, 0.40; OMeMV, 0.054. Titration of the dyes with double-stranded (ds)DNA resulted in bathochromic shifts and hypochromic effects in the visible absorption spectra. Association constants for interaction of the methylated dyes with dsDNA of approximately 1 x 10(5) M-1 were determined by Scatchard analysis of equilibrium dialysis and UV absorption titration data. Photolysis of the halogenated dyes with DNA under argon led to covalent bond formation with the nucleic acid; there was no evidence of covalent binding in the dark.

  17. 21 CFR 700.19 - Use of methylene chloride as an ingredient of cosmetic products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... cosmetic products. 700.19 Section 700.19 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.19 Use of methylene chloride as an ingredient of cosmetic products. (a) Methylene chloride has been...

  18. 21 CFR 700.19 - Use of methylene chloride as an ingredient of cosmetic products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... cosmetic products. 700.19 Section 700.19 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.19 Use of methylene chloride as an ingredient of cosmetic products. (a) Methylene chloride has been...

  19. 21 CFR 700.19 - Use of methylene chloride as an ingredient of cosmetic products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... cosmetic products. 700.19 Section 700.19 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.19 Use of methylene chloride as an ingredient of cosmetic products. (a) Methylene chloride has been...

  20. 21 CFR 700.19 - Use of methylene chloride as an ingredient of cosmetic products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... cosmetic products. 700.19 Section 700.19 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.19 Use of methylene chloride as an ingredient of cosmetic products. (a) Methylene chloride has been...

  1. 21 CFR 700.19 - Use of methylene chloride as an ingredient of cosmetic products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... cosmetic products. 700.19 Section 700.19 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.19 Use of methylene chloride as an ingredient of cosmetic products. (a) Methylene chloride has been...

  2. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Methylene blue-containing drugs for use in animals. 500.27 Section 500.27 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... according to label directions. The specific cause of the reaction was determined to be the methylene...

  3. Comparison of Accuracy in Calculation of Absorbed Dose to Patients Following Bone Scan with 99mTc-Marked Diphosphonates by Two Different Background Correction Methods

    PubMed Central

    Shahbazi-Gahrouei, Daryoush; Damoori, Mehri; Tavakoli, Mohammad Bagher; Moslehi, Masoud

    2016-01-01

    To improve the accuracy of the activity quantification and the image quality in scintigraphy, scatter correction is a vital procedure. The aim of this study is to compare the accuracy in calculation of absorbed dose to patients following bone scan with 99mTc-marked diphosphonates (99mTc-MDP) by two different methods of background correction in conjugate view method. This study involved 22 patients referring to the Nuclear Medicine Center of Shahid Chamran Hospital, Isfahan, Iran. After the injection of 99mTc-MDP, whole-body images from patients were acquired at 10, 60, 90, and 180 min. Organ activities were calculated using the conjugate view method by Buijs and conventional background correction. Finally, the absorbed dose was calculated using the Medical Internal Radiation Dosimetry (MIRD) technique. The results of this study showed that the absorbed dose per unit of injected activity (rad/mCi) ± standard deviation for pelvis bone, bladder, and kidneys by Buijs method was 0.19 ± 0.05, 0.08 ± 0.01, and 0.03 ± 0.01 and by conventional method was 0.13 ± 0.04, 0.08 ± 0.01, and 0.024 ± 0.01, respectively. This showed that Buijs background correction method had a high accuracy compared to conventional method for the estimated absorbed dose of bone and kidneys whereas, for the bladder, its accuracy was low. PMID:27014610

  4. Synthesis of novel 6,6'-methylene-bis-[3-(2-anilinoacetyl)-4-hydroxycoumarin] derivatives.

    PubMed

    Sanjeeva Reddy, Cherkupally; Raghu, Mekala

    2008-12-01

    The synthesis of novel 6,6'-methylene-bis-[3-(2-anilinoacetyl)-4-hydroxycoumarin] derivatives 6a-f was achieved in excellent yields from 6,6'-methylene-bis-[3-(2-bromoacetyl)-4-hydroxycoumarin] 5 and various arylamines. 5,5'-Methylene-bis-ethylsalicylate 3 was obtained by the esterfication of 5,5'-methylene-bis-salicylic acid 2 with ethanol, which was in turn obtained from salicylic acid 1 and formaldehyde. Cyclocondensation of 3 with ethyl acetoacetate resulted in 6,6'-methylene-bis-[3-acetyl-4-hydroxycoumarin] 4, which on selective alpha-bromination with molecular bromine in the presence of montmorillonite K10-AlCl(3) catalyst, in chloroform-ethyl acetate binary solvent mixture at room temperature, afforded the compound 5 in excellent yield. All the newly synthesized compounds were characterized by their spectral data.

  5. Terahertz Spectroscopy of Deuterated Methylene Bi-Radical CD_2

    NASA Astrophysics Data System (ADS)

    Ozeki, Hiroyuki; Bailleux, Stephane

    2015-06-01

    Methylene, the parent of the carbene compounds, plays a crucial role in many chemical reactions. This bi-radical is a known interstellar molecule that has been detected towards hot cores in dense interstellar clouds. CH_2 is also thought to be present in cometary atmospheres. In the gas phase chemical models of both dense and diffuse molecular clouds, CH_2 is a key intermediate in interstellar carbon chemistry which is produced primarily by dissociative recombination of the methyl ion, CH^+_3. Recently tentative detection of the mono-deuterated methyl ion, CH_2D^+ has been reported toward an infrared source in the vicinity of Orion. Deuterated methylene CHD and CD_2 can be produced from this ion or its counterpart CHD^+_2 by dissociative recombination with an electron: CH2D+ + e- → CHD+ H or {CH2 + D}, CHD2+ ~+ e- → CHD+ D or CD2 + H. Thus, both CHD and CD_2 can be observed in warm interstellar clouds, where the deuterium fractionation process is important. Precise laboratory reference data are desirable for radioastronomical observation of these molecules. Here we report on our high-resolution spectroscopic investigation on the deuterated methylene radical, CD_2 (X ^3B_1) up to 1.45 THz. At present time, eleven out of the twelve fine-structure components of four pure rotational transitions have been newly recorded, and these measurements double the number of previously observed transitions. CD_2 was generated in a discharge in CD_2CO which was obtained from the flash pyrolysis of acetic anhydride-d6 ((CD_3CO)_2O). Effort is currently made to measure the astronomically important 111 - 000 transition whose fine-structure components are predicted to occur at 1.224,1.228 and 1.234 THz. D. C. Lis, P. F. Goldsmith, E. A. Bergin et al. 2009, in Submillimeter Astrophysics and Technology, ASP Conf. Ser., 417, 23. H. Ozeki and S. Saito J. Chem. Phys. 1996, 104, 2167.

  6. Study of Methylene Blue adsorption on keratin nanofibrous membranes.

    PubMed

    Aluigi, A; Rombaldoni, F; Tonetti, C; Jannoke, L

    2014-03-15

    In this work, keratin nanofibrous membranes (mean diameter of about 220nm) were prepared by electrospinning and tested as adsorbents for Methylene Blue through batch adsorption tests. The adsorption capacity of the membranes was evaluated as a function of initial dye concentration, pH, adsorbent dosage, time and temperature. The adsorption capacity increased with increasing the initial dye concentration and pH, while it decreased with increasing the adsorbent dosage and temperature, indicating an exothermic process. The adsorption results indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich and Temkin isotherm models. A mean free energy evaluated through the Dubinin-Radushkevich model of about 16kJmol(-1), indicated a chemisorption process which occurred by ion exchange. The kinetic data were found to fit the pseudo-second-order model better than the pseudo-first-order model. The obtained results suggest that keratin nanofibrous membranes could be promising candidates as dye adsorption filters.

  7. Sequestration of Methylene Blue into Polyelectrolyte Complex Coacervates.

    PubMed

    Zhao, Mengmeng; Zacharia, Nicole S

    2016-08-01

    Polyelectrolyte complex coacervation is a process that has been proposed as a model for protocell formation due to its ability to compartmentalize chemicals in solution without a membrane. During the liquid-liquid phase separation that results in water rich and polyelectrolyte rich phases, small molecules present in solution selectively partition to one phase over the other. This sequestration is based on relative affinities. Here, a study of the sequestration of methylene blue (MB) into the complex coacervate phase of three pairs of synthetic polyelectrolytes is presented; branched polyethylene imine with polyacrylic acid, polyvinyl sulfonate, or poly(4-styrenesulfonic acid). These materials are characterized with UV-vis, zeta potential measurements, and dynamic light scattering. The branched polyethylene imine/poly(4-styrenesulfonic acid) system is shown to have a significantly higher sequestration capacity for the MB as compared to either of the other two systems, based on π-π interactions which are not possible in the other systems. PMID:27336461

  8. Methylene blue adsorption on a DMPA lipid langmuir monolayer.

    PubMed

    Giner Casares, Juan José; Camacho, Luis; Martín-Romero, Maria Teresa; López Cascales, José Javier

    2010-07-12

    Adsorption of methylene blue (MB) onto a dimyristoylphosphatidic acid (DMPA) Langmuir air/water monolayer is studied by molecular dynamics (MD) simulations, UV reflection spectroscopy and surface potential measurements. The free-energy profile associated with MB transfer from water to the lipid monolayer shows two minima of -66 and -60 kJ mol(-1) for its solid and gas phase, respectively, corresponding to a spontaneous thermodynamic process. From the position of the free-energy minima, it is possible to predict the precise location of MB in the interior of the DMPA monolayer. Thus, MB is accommodated in the phosphoryl or carbonyl region of the DMPA Langmuir air/water interface, depending on the isomorphic state (solid or gas phase, respectively). Reorientation of MB, measured from the bulk solution to the interior of the lipid monolayer, passes from a random orientation in bulk solution to an orientation parallel to the surface of the lipid monolayer when MB is absorbed. PMID:20544777

  9. Methylene blue adsorption on a DMPA lipid langmuir monolayer.

    PubMed

    Giner Casares, Juan José; Camacho, Luis; Martín-Romero, Maria Teresa; López Cascales, José Javier

    2010-07-12

    Adsorption of methylene blue (MB) onto a dimyristoylphosphatidic acid (DMPA) Langmuir air/water monolayer is studied by molecular dynamics (MD) simulations, UV reflection spectroscopy and surface potential measurements. The free-energy profile associated with MB transfer from water to the lipid monolayer shows two minima of -66 and -60 kJ mol(-1) for its solid and gas phase, respectively, corresponding to a spontaneous thermodynamic process. From the position of the free-energy minima, it is possible to predict the precise location of MB in the interior of the DMPA monolayer. Thus, MB is accommodated in the phosphoryl or carbonyl region of the DMPA Langmuir air/water interface, depending on the isomorphic state (solid or gas phase, respectively). Reorientation of MB, measured from the bulk solution to the interior of the lipid monolayer, passes from a random orientation in bulk solution to an orientation parallel to the surface of the lipid monolayer when MB is absorbed.

  10. Preparation of photocrosslinkable polystyrene methylene cinnamate nanofibers via electrospinning.

    PubMed

    Yi, Chuan; Nirmala, R; Navamathavan, R; Li, Xiang-Dan; Kim, Hak-Yong

    2011-10-01

    Nanoscaled photocrosslinkable polystyrene methylene cinnamate (PSMC) nanofibers were fabricated by electrospinning. The PSMC was prepared by the modification of polystyrene as a starting material via a two-step reaction process, chloromethylation and esterification. The chemical structure of PSMC was confirmed by 1H NMR and Fourier transform infrared spectroscopy (FT-IR). The photosensitivity of the PSMC was investigated using ultraviolet (UV) spectroscopic methods. Electrospun PSMC nanofiber mat showed excellent solubility in many organic solvents. UV irradiation of the electrospun mats led to photodimerization to resist dissolving in organic solvents. The morphology of the nanofiber was observed by scanning electron microscopy (SEM) and the result indicated that the average diameter of nanofibers is 350 nm and the crosslinked nanofibers were not collapsed after dipping into organic solvent showing good solvent-stability. This photocrosslinked nanofibers has the potential application in filtration, catalyst carrier and protective coating.

  11. Methylene blue mediated laser therapy of maxillary sinusitis

    NASA Astrophysics Data System (ADS)

    Genina, E. A.; Bashkatov, A. N.; Chikina, E. E.; Knyazev, A. B.; Mareev, O. V.; Tuchin, V. V.

    2006-07-01

    The purpose of the present work is a clinical study of photodynamic therapy of maxillary sinusitis. 0.1%-Methylene Blue aqueous solution in combination with He-Ne laser irradiation (632.8 nm) have been used for treatment of maxillary sinus mucous of patients with acute and chronic maxillary sinusitis. The differences between the results of the treatment with dye and light versus treatment with a drug for every group of patients were statistically analyzed by Student’s t test. The efficacy of the photodynamic therapy was estimated with the use of the following criteria: the state of respiration, olfaction, duration of purulent discharge, reconstruction of transport function of ciliary epithelium, etc. The obtained results have shown that the photodynamic therapy is effective in comparison with conservative methods of treatment of the disease.

  12. Assess health effects associated with dichloromethane (methylene chloride). Final report

    SciTech Connect

    Not Available

    1988-03-09

    On August 13-14, 1987 the Halogenated Organics Subcommittee of the Science Advisory Board's Environmental Health Committee met in Washington, D.C. to review two documents prepared by EPA's Office of Research and Development that assess health effects associated with dichloromethane (methylene chloride). The documents included: a June 1987 Draft Technical Analysis of New Methods and Data Regarding Dichloromethane: Pharmacokinetics, Mechanism of Action and Epidemiology, a July 1987 Draft Addendum to the Health Assessment Document for Dichloromethane: Pharmacokinetics, Mechanism of Action and Epidemiology. The Subcommittees concluded that the Addendum was one of the best documents it has received in terms of its clarity, coverage of the data and analysis of scientific issues. The document clearly demonstrates the potential utility of pharmacokinetics data in risk assessment.

  13. Solvent mimicry with methylene carbene to probe protein topography.

    PubMed

    Gómez, Gabriela Elena; Monti, José Luis E; Mundo, Mariana Rocío; Delfino, José María

    2015-10-01

    The solvent accessible surface area (SASA) of the polypeptide chain plays a key role in protein folding, conformational change, and interaction. This fundamental biophysical parameter is elusive in experimental measurement. Our approach to this problem relies on the reaction of the minimal photochemical reagent diazirine (DZN) with polypeptides. This reagent (i) exerts solvent mimicry because its size is comparable to water and (ii) shows scant chemical selectivity because it generates extremely reactive methylene carbene. Methylation gives rise to the EM (extent of modification) signal, which is useful for scrutinizing the conformational change triggered by Ca(2+) binding to calmodulin (CaM). The increased EM observed for the full protein is dominated by the enhanced exposure of hydrophobic area in Ca(2+)-CaM. Fragmentation allowed us to quantify the methylene incorporation at specific sites. Peptide 91-106 reveals a major reorganization around the calcium 151 binding site, resulting in local ordering and a greater exposure of the hydrophobic surface. Additionally, this technique shows a high sensitivity to probe recognition between CaM and melittin (Mel). The large decrease in EM indicates the occlusion of a significant hydrophobic area upon complexation. Protection from labeling reveals a larger involvement of the N-terminal and central regions of CaM in this interaction. Despite its smaller size, Mel's differential exposure can also be quantified. Moreover, MS/MS fragmentation realizes the goal of extending the resolution of labeled sites at the amino acid level. Overall, DZN labeling emerges as a useful footprinting method capable of shedding light on physiological conformational changes and interactions. PMID:26348271

  14. Fatal exposure to methylene chloride among bathtub refinishers - United States, 2000-2011.

    PubMed

    2012-02-24

    In 2010, the Michigan Fatality Assessment and Control Evaluation program conducted an investigation into the death of a bathtub refinisher who used a methylene chloride-based paint stripping product marketed for use in aircraft maintenance. The program identified two earlier, similar deaths in Michigan. Program staff members notified CDC's National Institute for Occupational Safety and Health (NIOSH), which in turn notified the Occupational Safety and Health Administration (OSHA). In addition to the three deaths, OSHA identified 10 other bathtub refinisher fatalities associated with methylene chloride stripping agents that had been investigated in nine states during 2000-2011. Each death occurred in a residential bathroom with inadequate ventilation. Protective equipment, including a respirator, either was not used or was inadequate to protect against methylene chloride vapor, which has been recognized as potentially fatal to furniture strippers and factory workers but has not been reported previously as a cause of death among bathtub refinishers. Worker safety agencies, public health agencies, methylene chloride-based stripper manufacturers, and trade organizations should communicate the extreme hazards of using methylene chloride-based stripping products in bathtub refinishing to employers, workers, and consumers. Employers should strongly consider alternative methods of bathtub stripping and always ensure worker safety protections that reduce the risk for health hazards to acceptable levels. Employers choosing to use methylene chloride-based stripping products must comply with OSHA's standard to limit methylene chloride exposures to safe levels. PMID:22357403

  15. Methylene blue prevents retinal damage in an experimental model of ischemic proliferative retinopathy.

    PubMed

    Rey-Funes, Manuel; Larrayoz, Ignacio M; Fernández, Juan C; Contartese, Daniela S; Rolón, Federico; Inserra, Pablo I F; Martínez-Murillo, Ricardo; López-Costa, Juan J; Dorfman, Verónica B; Martínez, Alfredo; Loidl, César F

    2016-06-01

    Perinatal asphyxia induces retinal lesions, generating ischemic proliferative retinopathy, which may result in blindness. Previously, we showed that the nitrergic system was involved in the physiopathology of perinatal asphyxia. Here we analyze the application of methylene blue, a well-known soluble guanylate cyclase inhibitor, as a therapeutic strategy to prevent retinopathy. Male rats (n = 28 per group) were treated in different ways: 1) control group comprised born-to-term animals; 2) methylene blue group comprised animals born from pregnant rats treated with methylene blue (2 mg/kg) 30 and 5 min before delivery; 3) perinatal asphyxia (PA) group comprised rats exposed to perinatal asphyxia (20 min at 37°C); and 4) methylene blue-PA group comprised animals born from pregnant rats treated with methylene blue (2 mg/kg) 30 and 5 min before delivery, and then the pups were subjected to PA as above. For molecular studies, mRNA was obtained at different times after asphyxia, and tissue was collected at 30 days for morphological and biochemical analysis. Perinatal asphyxia produced significant gliosis, angiogenesis, and thickening of the inner retina. Methylene blue treatment reduced these parameters. Perinatal asphyxia resulted in a significant elevation of the nitrergic system as shown by NO synthase (NOS) activity assays, Western blotting, and (immuno)histochemistry for the neuronal isoform of NOS and NADPH-diaphorase activity. All these parameters were also normalized by the treatment. In addition, methylene blue induced the upregulation of the anti-angiogenic peptide, pigment epithelium-derived factor. Application of methylene blue reduced morphological and biochemical parameters of retinopathy. This finding suggests the use of methylene blue as a new treatment to prevent or decrease retinal damage in the context of ischemic proliferative retinopathy. PMID:26984891

  16. Methylene chloride: a 2-year inhalation toxicity and oncogenicity study in rats

    SciTech Connect

    Nitschke, K.D.; Burek, J.D.; Bell, T.J.; Kociba, R.J.; Rampy, L.W.; McKenna, M.J.

    1988-07-01

    Male and female Sprague-Dawley rats were exposed to 0, 50, 200, or 500 ppm methylene chloride for 6 hr/day, 5 days/week for 2 years. Blood carboxyhemoglobin levels were elevated in a dose-dependent (less than linear) manner in rats exposed to 50-500 ppm methylene chloride. Histopathologic lesions related to methylene chloride exposure were confined to the liver and mammary tissue of rats. An increased incidence of hepatocellular vacuolization was observed in male and female rats exposed to 500 ppm methylene chloride. Female rats exposed to 500 ppm methylene chloride also had an increased incidence of multinucleated hepatocytes and number of spontaneous benign mammary tumors/tumor-bearing rat (adenomas, fibromas, and fibroadenomas with no progression toward malignancy); the incidence of benign mammary tumors in female rats exposed to 50 or 200 ppm methylene chloride was comparable to historical control values. No increase in the number of any malignant tumor type was observed in rats exposed to concentrations as high as 500 ppm methylene chloride. Additional groups of female rats were exposed to 500 ppm methylene chloride for the first 12 months or the last 12 months of the 24-month study. The response observed in female rats exposed to 500 ppm for the first 12 months was the same as that observed in female rats exposed to 500 ppm for 2 years. Conversely, the response observed in female rats exposed to 500 ppm during the last 12 months of the study was similar to that observed in control animals. Based upon the results of this study, the no-adverse-effect level for chronic inhalation exposure of Sprague-Dawley rats was judged to be 200 ppm methylene chloride.

  17. 99MTc-Hexamethylpropyleneamine Oxime Imaging for Early Detection of Acute Lung Injury in Rats Exposed to Hyperoxia or Lipopolysaccharide Treatment.

    PubMed

    Audi, Said H; Clough, Anne V; Haworth, Steven T; Medhora, Meetha; Ranji, Mahsa; Densmore, John C; Jacobs, Elizabeth R

    2016-10-01

    Tc-Hexamethylpropyleneamine oxime (HMPAO) is a clinical single-photon emission computed tomography biomarker of tissue oxidoreductive state. Our objective was to investigate whether HMPAO lung uptake can serve as a preclinical marker of lung injury in two well-established rat models of human acute lung injury (ALI).Rats were exposed to >95% O2 (hyperoxia) or treated with intratracheal lipopolysaccharide (LPS), with first endpoints obtained 24 h later. HMPAO was administered intravenously before and after treatment with the glutathione-depleting agent diethyl maleate (DEM), scintigraphy images were acquired, and HMPAO lung uptake was quantified from the images. We also measured breathing rates, heart rates, oxygen saturation, bronchoalveolar lavage (BAL) cell counts and protein, lung homogenate glutathione (GSH) content, and pulmonary vascular endothelial filtration coefficient (Kf).For hyperoxia rats, HMPAO lung uptake increased after 24 h (134%) and 48 h (172%) of exposure. For LPS-treated rats, HMPAO lung uptake increased (188%) 24 h after injury and fell with resolution of injury. DEM reduced HMPAO uptake in hyperoxia and LPS rats by a greater fraction than in normoxia rats. Both hyperoxia exposure (18%) and LPS treatment (26%) increased lung homogenate GSH content, which correlated strongly with HMPAO uptake. Neither of the treatments had an effect on Kf at 24 h. LPS-treated rats appeared healthy but exhibited mild tachypnea, BAL, and histological evidence of inflammation, and increased wet and dry lung weights. These results suggest the potential utility of HMPAO as a tool for detecting ALI at a phase likely to exhibit minimal clinical evidence of injury.

  18. Metachromasy as an indicator of photostabilization of methylene blue adsorbed to clays and minerals.

    PubMed

    Samuels, Maya; Mor, Omer; Rytwo, Giora

    2013-04-01

    The influence of methylene blue adsorption to different clays on its photodegradation was studied. Methylene blue in solution was decomposed by sunlight in a zero-order process. Adsorption to some clay minerals (sepiolite and vermiculite) and a zeolite (clinoptilolite) accelerated the degradation process, and converted it to a first-order reaction. On the other hand, adsorption to other clay minerals (palygorskite and montmorillonite) stabilized the dye and prevented its degradation. Interestingly, in the clay-dye complexes that exhibited stability, clear metachromasy of the adsorbed methylene blue occurred, whereas the effect was not observed in the clay-dye complexes that underwent photodegradation.

  19. ON THE NATURE OF THE DYE PENETRATING THE VACUOLE OF VALONIA FROM SOLUTIONS OF METHYLENE BLUE.

    PubMed

    Irwin, M

    1927-07-20

    When uninjured cells of Valonia are placed in methylene blue dissolved in sea water it is found, after 1 to 3 hours, that at pH 5.5 practically no dye penetrates, while at pH 9.5 more enters the vacuole. As the cells become injured more dye enters at pH 5.5, as well as at pH 9.5. No dye in reduced form is found in the sap of uninjured cells exposed from 1 to 3 hours to methylene blue in sea water at both pH values. When uninjured cells are placed in azure B solution, the rate of penetration of dye into the vacuole is found to increase with the rise in the pH value of the external dye solution. The partition coefficient of the dye between chloroform and sea water is higher at pH 9.5 than at pH 5.5 with both methylene blue and azure B. The color of the dye in chloroform absorbed from methylene blue or from azure B in sea water at pH 5.5 is blue, while it is reddish purple when absorbed from methylene blue and azure B at pH 9.5. Dry salt of methylene blue and azure B dissolved in chloroform appears blue. It is shown that chiefly azure B in form of free base is absorbed by chloroform from methylene blue or azure B dissolved in sea water at pH 9.5, but possibly a mixture of methylene blue and azure B in form of salt is absorbed from methylene blue at pH 5.5, and azure B in form of salt is absorbed from azure B in sea water at pH 5.5. Spectrophotometric analysis of the dye shows the following facts. 1. The dye which is absorbed by the cell wall from methylene blue solution is found to be chiefly methylene blue. 2. The dye which has penetrated from methylene blue solution into the vacuole of uninjured cells is found to be azure B or trimethyl thionine, a small amount of which may be present in a solution of methylene blue especially at a high pH value. 3. The dye which has penetrated from methylene blue solution into the vacuole of injured cells is either methylene blue or a mixture of methylene blue and azure B. 4. The dye which is absorbed by chloroform from methylene

  20. Amended safety assessment of formaldehyde and methylene glycol as used in cosmetics.

    PubMed

    Boyer, Ivan J; Heldreth, Bart; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2013-01-01

    Formaldehyde and methylene glycol may be used safely in cosmetics if established limits are not exceeded and are safe for use in nail hardeners in the present practices of use and concentration, which include instructions to avoid skin contact. In hair-smoothing products, however, in the present practices of use and concentration, formaldehyde and methylene glycol are unsafe. Methylene glycol is continuously converted to formaldehyde, and vice versa, even at equilibrium, which can be easily shifted by heating, drying, and other conditions to increase the amount of formaldehyde. This rapid, reversible formaldehyde/methylene glycol equilibrium is distinguished from the slow, irreversible release of formaldehyde resulting from the so-called formaldehyde releaser preservatives, which are not addressed in this safety assessment (formaldehyde releasers may continue to be safely used in cosmetics at the levels established in their individual Cosmetic Ingredient Review safety assessments). PMID:24335968

  1. Quantum dot/methylene blue FRET mediated NIR fluorescent nanomicelles with large Stokes shift for bioimaging.

    PubMed

    Li, Li; Liu, Jianbo; Yang, Xiaohai; Peng, Zhihong; Liu, Wei; Xu, Jianguo; Tang, Jinlu; He, Xiaoxiao; Wang, Kemin

    2015-10-01

    Here we present a novel large Stokes shifting NIR fluorescent nanomicelle through the encapsulation of a quantum dot/methylene blue FRET pair, which is employed as an excellent contrast reagent for NIR fluorescence bioimaging. PMID:26267557

  2. Safety of methylene blue dye for lymphatic mapping in patients taking selective serotonin reuptake inhibitors.

    PubMed

    Shah-Khan, Miraj G; Lovely, Jenna; Degnim, Amy C

    2012-11-01

    Methylene blue dye has an important role in lymphatic mapping for sentinel lymph node surgery. A recent safety announcement from the US Food and Drug Administration warned physicians about possible serious central nervous system reactions in patients on serotonergic medications who received intravenous methylene blue for the identification of parathyroid glands. This report summarizes evidence from the Food and Drug Administration's announcement and methylene blue pharmacokinetics. The authors conclude that the use of methylene blue dye at low doses for lymphatic mapping likely carries very little risk for serotonin neurotoxicity, although breast surgeons should be aware of this potential complication in the event of mental status or neuromuscular changes in patients after lymphatic mapping.

  3. Removal of methylene blue from wastewater using fly ash as an adsorbent by hydrocyclone.

    PubMed

    Rastogi, K; Sahu, J N; Meikap, B C; Biswas, M N

    2008-10-30

    The excessive release of color into the environment is a major concern worldwide. Adsorption process is among the most effective techniques for color removal from wastewater and fly ash has been widely used as an adsorbent. Therefore, this study was carried out to understand the adsorption behavior of methylene blue from aqueous systems onto fly ash using the continuous mode. Continuous mode sorption experiments were carried out to remove methylene blue from its aqueous solutions in hydrocyclone equipment. The experiments were performed at constant temperature and dimensions of hydrocyclone with variation of flows through the equipment, concentrations of methylene blue solutions and fly ash concentration, respectively. A maximum removal of 58.24% was observed at adsorbent dosage of 900 mg/l at pH 6.75 for an initial methylene blue concentration of 65 mg/l.

  4. Fast and considerable adsorption of methylene blue dye onto graphene oxide.

    PubMed

    Zhang, Wenjie; Zhou, Chunjiao; Zhou, Weichang; Lei, Aihua; Zhang, Qinglin; Wan, Qiang; Zou, Bingsuo

    2011-07-01

    The quite efficient adsorption of methylene blue dye from an aqueous solution by graphene oxide was studied. The favorable electrostatic attraction is the main interaction between methylene blue and graphene oxide. As graphene oxide has the special nanostructural properties and negatively charged surface, the positively charged methylene blue molecules can be easily adsorbed on it. In the aqueous solution of methylene blue at 293 K, the adsorption data could be fitted by the Langmuir equation with a maximum adsorption amount of 1.939 mg/mg and a Langmuir adsorption equilibrium constant of 18.486 mL/mg. The adsorption amount increased with the increase of the solution pH (3-11), was not affected significantly by KCl under the examined condition and the adsorption process was exothermic in nature. The fast and considerable adsorption of graphene oxide could be regarded as a potential adsorbent for cationic dye removal in wastewater treatment process.

  5. Adsorption of methylene blue onto bamboo-based activated carbon: kinetics and equilibrium studies.

    PubMed

    Hameed, B H; Din, A T M; Ahmad, A L

    2007-03-22

    Bamboo, an abundant and inexpensive natural resource in Malaysia was used to prepare activated carbon by physiochemical activation with potassium hydroxide (KOH) and carbon dioxide (CO(2)) as the activating agents at 850 degrees C for 2h. The adsorption equilibrium and kinetics of methylene blue dye on such carbon were then examined at 30 degrees C. Adsorption isotherm of the methylene blue (MB) on the activated carbon was determined and correlated with common isotherm equations. The equilibrium data for methylene blue adsorption well fitted to the Langmuir equation, with maximum monolayer adsorption capacity of 454.2mg/g. Two simplified kinetic models including pseudo-first-order and pseudo-second-order equation were selected to follow the adsorption processes. The adsorption of methylene blue could be best described by the pseudo-second-order equation. The kinetic parameters of this best-fit model were calculated and discussed.

  6. Formaldehyde and methylene glycol equivalence: critical assessment of chemical and toxicological aspects.

    PubMed

    Golden, R; Valentini, M

    2014-07-01

    Due largely to the controversy concerning the potential human health effects from exposure to formaldehyde gas in conjunction with the misunderstanding of the well-established equilibrium relationship with its hydrated reaction product, methylene glycol, the concept of chemical equivalence between these two distinctly different chemicals has been adopted by regulatory authorities. Chemical equivalence implies not only that any concentration of methylene glycol under some condition of use would be nearly or completely converted into formaldehyde gas, but also that these two substances would be toxicologically equivalent as well. A relatively simple worst case experiment using 37% formalin (i.e., concentrated methylene glycol) dispels the concept of chemical equivalence and a review of relevant literature demonstrates that methylene glycol has no inherent toxicity apart from whatever concentration of formaldehyde that might be present in equilibrium with such solutions.

  7. Reaction pathway of methylenation of carbonyl compounds with bis(iodozincio)methane.

    PubMed

    Sada, Mutsumi; Komagawa, Shinsuke; Uchiyama, Masanobu; Kobata, Masami; Mizuno, Tsuyoshi; Utimoto, Kiitiro; Oshima, Koichiro; Matsubara, Seijiro

    2010-12-15

    About 40 years have passed since methylene dizinc reagent was discovered as a substitute for Wittig reagent. Density functional theory (DFT) calculations have been performed to understand the reaction pathways of methylenation of carbonyl compounds with bis(iodozincio)methane. The present computational/theoretical study concluded that the methylenation reaction with gem-dizinc reagent proceeds as a two-step reaction, that is, methylene addition (RDS) and olefination. In the first step, the nucleophilic attack of the CH2 group enhanced by two Zn proceeds under the assistance of the electrophilic activation of the carbonyl group with the Zn atom. In the second step, the olefination is facilitated by both Zn atoms of the gem-dizinc reagent without an electron transfer process. PMID:21082850

  8. Photoacoustic lifetime imaging of dissolved oxygen using methylene blue

    NASA Astrophysics Data System (ADS)

    Ashkenazi, Shai

    2010-07-01

    Measuring distribution of dissolved oxygen in biological tissue is of prime interest for cancer diagnosis, prognosis, and therapy optimization. Tumor hypoxia indicates poor prognosis and resistance to radiotherapy. Despite its major clinical significance, no current imaging modality provides direct imaging of tissue oxygen. We present preliminary results demonstrating the potential of photoacoustic lifetime imaging (PALI) for noninvasive, 3-D imaging of tissue oxygen. The technique is based on photoacoustic probing of the excited state lifetime of methylene blue (MB) dye. MB is an FDA-approved water soluble dye with a peak absorption at 660 nm. A double pulse laser system (pump probe) is used to excite the dye and probe its transient absorption by detecting photoacoustic emission. The relaxation rate of MB depends linearly on oxygen concentration. Our measurements show high photoacoustic signal contrast at a probe wavelength of 810 nm, where the excited state absorption is more than four times higher than the ground state absorption. Imaging of a simple phantom is demonstrated. We conclude by discussing possible implementations of the technique in clinical settings and combining it with photodynamic therapy (PDT) for real-time therapy monitoring.

  9. Adsorption of methylene blue onto sonicated sepiolite from aqueous solutions.

    PubMed

    Küncek, Ilknur; Sener, Savaş

    2010-01-01

    The aim of the present study is to enhance the methylene blue (MB) adsorption of sepiolite by ultrasonic treatment. The natural sepiolite was pretreated by sonication to improve the surface characteristics and enhance the dye uptake capacity. Sonication process resulted in a significant increase in the specific surface area (SSA) of sepiolite. The FTIR spectrum of the sonicated sepiolite indicates that the tetrahedral sheet is probably distorted after sonication process. The effect of various parameters such as sonication, pH, initial dye concentration and temperature on dye adsorption has been investigated. The adsorbed amount of MB on sepiolite increased after sonication as well as with increasing pH and temperature. The experimental data were evaluated by applying the pseudo-first- and second-order, and the intraparticle diffusion adsorption kinetic models. Adsorption process of MB onto sepiolite followed the pseudo-second-order rate expression. The experimental data were analyzed by Langmuir and Freundlich isotherms, and found that the isotherm data were reasonably well correlated by Langmuir isotherm. Maximum monolayer adsorption capacity of sepiolite for MB increased from 79.37 to 128.21 mg/g after the sonication. Various thermodynamic parameters, such as Delta G(0), Delta H(0) and DeltaS(0) were calculated. The thermodynamics of MB/sepiolite system indicated spontaneous and endothermic nature of the process. Adsorption measurements showed that the process was very fast and physical in nature.

  10. Removal of methylene blue by lava adsorption and catalysis oxidation.

    PubMed

    Ma, Jianfeng; Zhang, Jinbao; Li, Dinglong

    2010-03-01

    Adsorption has been found to be effective for the removal of dyes from effluent; however, the contaminant will cause secondary pollution if it is not properly treated. In this paper, the ability of lava as a low-cost adsorbent and catalyst for the removal of a commercial dye, Methylene Blue (MB), from aqueous solution has been investigated under various experimental conditions. It was found that lava had a high efficiency (more than 98%) for MB removal by adsorption. The adsorption equilibrium data can be fitted well by the Langmuir adsorption isotherm model. The adsorption kinetics was shown to be pseudo-second-order. After adsorption the contaminant could be catalysis oxidized by lava with the aids of H2O2 and ultrasound. The result showed that 95% of the MB could be decomposed in 100 min with the aid of ultrasound at 85 W/cm2. Overall, this study demonstrates lava as a promising material for wastewater treatment to remove and decompose dyes in a single treatment step.

  11. Degradation of Methylene Blue Using Biologically Synthesized Silver Nanoparticles

    PubMed Central

    Vanaja, M.; Paulkumar, K.; Baburaja, M.; Rajeshkumar, S.; Gnanajobitha, G.; Malarkodi, C.; Sivakavinesan, M.; Annadurai, G.

    2014-01-01

    Nowadays plant mediated synthesis of nanoparticles has great interest and achievement due to its eco-benign and low time consuming properties. In this study silver nanoparticles were successfully synthesized by using Morinda tinctoria leaf extract under different pH. The aqueous leaf extract was added to silver nitrate solution; the color of the reaction medium was changed from pale yellow to brown and that indicates reduction of silver ions to silver nanoparticles. Thus synthesized silver nanoparticles were characterized by UV-Vis spectrophotometer. Dispersity and morphology was characterized by scanning electron microscope (SEM); crystalline nature and purity of synthesized silver nanoparticles were revealed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). FTIR spectrum was examined to identify the effective functional molecules responsible for the reduction and stabilization of silver nanoparticles synthesized by leaf extract. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Green synthesized silver nanoparticles were effectively degrading the dye nearly 95% at 72 h of exposure time. PMID:24772055

  12. [Adsorption of methylene blue onto vanadium-doped magnetite].

    PubMed

    Zhong, Yuan-Hong; Liang, Xiao-Liang; Zhu, Jian-Xi; He, Hong-Ping; Yuan, Peng

    2010-06-01

    A series of vanadium-doped magnetite (Fe3-x VxO4, x < 0.4) synthesized by an oxidation-precipitation method, were characterized using chemical analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetric and differential scanning calorimetry (TG-DSC) analyses. The obtained results show that the synthetic Fe3-x VxO4 has spinel structure while vanadium mostly replaces Fe3+ in the octahedral sites. The synthetic Fe3-x VxO4 is magnetic material, with crystal size ranging from 28 to 35 nm. The substitution of vanadium in the magnetite structure increases the amount of surface hydroxyls. The experimental adsorption results indicate that, in neutral pH condition, the maximum adsorption capacities of Fe3-x VxO4 increase obviously with the increase of vanadium concentration in magnetite while the adsorption isotherm complies well with the Langmuir model. The adsorption of methylene blue (MB) on Fe3-x VxO4 can get equilibrium in the first 25 min, supporting a pseudo-second order equation. Moreover, the rise of the solution pH value results in an increase of the adsorption capability of MB on Fe3-x VxO4.

  13. A Novel Use of Methylene Blue in the Pediatric ICU.

    PubMed

    Rutledge, Chrystal; Brown, Brian; Benner, Kimberley; Prabhakaran, Priya; Hayes, Leslie

    2015-10-01

    Methylene blue (MB) is a medication commonly used to treat methemoglobinemia, reducing methemoglobin to hemoglobin. A novel use of MB, as detailed here, is in the treatment of refractory hypotension. A number of reports have detailed use of MB for this purpose in adults, but few data in pediatrics. A 22-month-old girl with Noonan syndrome, biventricular hypertrophic cardiomyopathy, and chronic positive pressure ventilation developed shock with tachycardia, hypotension, and fever after 3 days of diarrhea. She was critically ill, with warm extremities, bounding pulses, and brisk capillary refill. Laboratory tests revealed metabolic acidosis, low mixed venous oxygen saturation, and leukocytosis with bandemia. Treatment of severe septic shock was initiated with fluid resuscitation, inotropic support, sedation, and paralysis. She remained hypotensive despite norepinephrine at 0.7 μg/kg per minute, dopamine at 20 μg/kg per minute, and vasopressin at 0.04 U/kg per hour. Her vasoplegic shock worsened, despite aggressive conventional therapy. Intravenous MB was initiated, with a loading dose of 1 mg/kg followed by a continuous infusion at 0.25 mg/kg per hour. Upon initiation of MB, her systolic blood pressure increased by 33 points (40% increase), and diastolic blood pressure increased by 20 points (46% increase). She was able to wean off all inotropes quickly after initiation of MB. MB should be considered in the setting of refractory vasoplegic shock in the PICU. PMID:26347436

  14. Methylene Blue to Treat Protamine-induced Anaphylaxis Reactions. An Experimental Study in Pigs

    PubMed Central

    Albuquerque, Agnes Afrodite S.; Margarido, Edson A.; Menardi, Antonio Carlos; Scorzoni Filho, Adilson; Celotto, Andrea Carla; Rodrigues, Alfredo J.; Vicente, Walter Vilella A.; Evora, Paulo Roberto B.

    2016-01-01

    OBJECTIVE: To examine if methylene blue (MB) can counteract or prevent protamine (P) cardiovascular effects. METHODS: The protocol included five heparinized pig groups: Group Sham -without any drug; Group MB - MB 3 mg/kg infusion; Group P - protamine; Group P/MB - MB after protamine; Group MB/P - MB before protamine. Nitric oxide levels were obtained by the nitric oxide/ozone chemiluminescence method, performed using the Nitric Oxide Analizer 280i (Sievers, Boulder, CO, USA). Malondialdehyde plasma levels were estimated using the thiobarbiturate technique. RESULTS: 1) Groups Sham and MB presented unchanged parameters; 2) Group P - a) Intravenous protamine infusion caused mean arterial pressure decrease and recovery trend after 25-30 minutes, b) Cardiac output decreased and remained stable until the end of protamine injection, and c) Sustained systemic vascular resistance increased until the end of protamine injection; 3) Methylene blue infusion after protamine (Group P/MB) - a) Marked mean arterial pressure decreased after protamine, but recovery after methylene blue injection, b) Cardiac output decreased after protamine infusion, recovering after methylene blue infusion, and c) Sustained systemic vascular resistance increased after protamine infusion and methylene blue injections; 4) Methylene blue infusion before protamine (Group MB/P) - a) Mean arterial pressure decrease was less severe with rapid recovery, b) After methylene blue, there was a progressive cardiac output increase up to protamine injection, when cardiac output decreased, and c) Sustained systemic vascular resistance decreased after protamine, followed by immediate Sustained systemic vascular resistance increase; 5) Plasma nitrite/nitrate and malondialdehyde values did not differ among the experimental groups. CONCLUSION: Reviewing these experimental results and our clinical experience, we suggest methylene blue safely prevents and treats hemodynamic protamine complications, from the endothelium

  15. Insecticidal Activity of α-Methylene-γ-butyrolactone against Several Insect Pests.

    PubMed

    Datta, P K; Kim, C S; Hara, T; Itoh, E; Horiike, M

    1999-01-01

    α-Methylene-γ-butyrolactone (tulipalin A), which has been found to possess effective insecticidal activity against Thrips palmi (Thysanoptera; Thripinae), was examined on several insect pests. This compound caused high mortality against thrips species such as Frankliniella occidentallis and Frankliniella intonsa. In addition, some mortality was observed against other agricultural pest species. It is considered that α-methylene-γ-butyrolactone has a wide spectrum of insecticidal activity.

  16. Can methylene blue only be used in sentinel lymph node biopsy for breast cancer?

    PubMed

    Golshan, Mehra; Nakhlis, Faina

    2006-01-01

    Sentinel lymph node biopsy (SLNB) has become an accepted standard of care to stage the axilla for clinically node-negative early stage breast cancer. In experienced hands, studies have shown an acceptable rate of identification of the sentinel lymph node (SLN) with blue dye only. Lymphazurin is occasionally associated with severe allergic reaction, including anaphylaxis and death. The use of methylene blue alone as a method of identifying the SLN in breast cancer has been reported once previously in the literature. Methylene blue may be an acceptable alternative with fewer deleterious side effects. Medical records of patients, who underwent sentinel node mapping between September 2003 and March 2005 by two surgeons at an academic medical center were reviewed. SLN mapping was performed by periareolar injection of 5 cc of 1% methylene blue. All patients with positive SLNs underwent completion axillary node dissection. During the study period, 141 consecutive patients with clinically node-negative axillas and without evidence of inflammatory breast cancer underwent SLNB with injection of methylene blue only. A SLN was identified in 136 of 141 patients (96.5%). Thirty-three of 136 SLNs (24%) harbored metastatic disease. No cases of anaphylaxis were noted. In experienced hands, methylene blue alone is a highly sensitive method of detecting SLNs. Avoiding the greater frequency of allergic reactions seen with lymphazurin is an important advantage of methylene blue.

  17. Methylene blue solder re-absorption in microvascular anastomoses

    NASA Astrophysics Data System (ADS)

    Birch, Jeremy F.; Hepplewhite, J.; Frier, Malcolm; Bell, Peter R. F.

    2003-06-01

    Soldered vascular anastomoses have been reported using several chromophores but little is known of the optimal conditions for microvascular anastomosis. There are some indications of the optimal protein contents of a solder, and the effects of methylene blue on anastomotic strength. The effects of varying laser power density in vivo have also been described, showing a high rate of thrombosis with laser power over 22.9Wcm-2. However no evidence exists to describe how long the solder remains at the site of the anastomosis. Oz et al reported that the fibrin used in their study had been almost completely removed by 90 days but without objective evidence of solder removal. In order to address the issue of solder re-absorption from the site of an anastomosis we used radio-labelled albumin (I-125) incorporated into methylene blue based solder. This was investigated in both the situation of the patent and thrombosed anastomosis with anastomoses formed at high and low power. Iodine-125 (half life: 60.2 days) was covalently bonded to porcine albumin and mixed with the solder solution. Radio-iodine has been used over many years to determine protein turnover using either I-125 or I-131. Iodine-125 labelled human albumin is regularly used as a radiopharmaceutical tool for the determination of plasma volume. Radio-iodine has the advantages of not affecting protein metabolism and the label is rapidly excreted after metabolic breakdown. Labelling with chromium (Cr-51) causes protein denaturation and is lost from the protein with time. Labelled albumin has been reported in human studies over a 21-day period, with similar results reported by Matthews. Most significantly McFarlane reported a different rate of catabolism of I-131 and I-125 over a 22-day period. The conclusion from this is that the rate of iodine clearance is a good indicator of protein catabolism. In parallel with the surgery a series of blank standards were prepared with a known mass of solder to correct for isotope

  18. Methylene blue mediated photodynamic therapy for resistant plaque psoriasis.

    PubMed

    Salah, Manal; Samy, Nevien; Fadel, Maha

    2009-01-01

    Topical treatment of resistant psoriatic plaque stage lesions may be difficult and the systemic therapies seem inappropriate. Therefore, a topical 0.1% methylene blue (MB) hydrogel was prepared and evaluated for percent drug content, drug uniformity, pH, rheological and organoleptic characters such as feel tackiness, grittiness sensation, and transparency in addition to release kinetics study in vitro. The efficiency of the photodynamic therapy (PDT) of MB photo-activated using 565 mW Light emitting diode (LED) 670 nm was evaluated in patients with resistant plaque psoriasis. The gel was evaluated in single blinded study. The patients were subjected to repeated sessions of irradiation, skin biopsies from each patient in the beginning and at the end of the sessions were taken for histopathological studies. Results showed the hydrogel was transparent nongritty and the drug uniformly dispersed with pH=7.2 and viscosity value=25.04 Pa. The drug content was found to be 99.4 +/- 0.15 %. Drug release was following zero order kinetics with rate constant K=0.348 +/- 0.01 and T(1/2) = 0.95 +/- 0.5 hours. Sixteen patients experienced complete clearance of their treated lesions. Skin appeared normal in color, texture, and pliability with no complications indicating the lack of skin sensitivity. Histopathological examinations showed nearly normal epidermis at the end of all sessions. The authors concluded that the prepared hydrogel was safe, stable, and very effective. The results are encouraging to accept MB as a photosensitizer for PDT and as a safe and effective method for treatment of selected cases of resistant localized psoriasis PMID:19180895

  19. Methylene blue mediated photodynamic therapy for resistant plaque psoriasis.

    PubMed

    Salah, Manal; Samy, Nevien; Fadel, Maha

    2009-01-01

    Topical treatment of resistant psoriatic plaque stage lesions may be difficult and the systemic therapies seem inappropriate. Therefore, a topical 0.1% methylene blue (MB) hydrogel was prepared and evaluated for percent drug content, drug uniformity, pH, rheological and organoleptic characters such as feel tackiness, grittiness sensation, and transparency in addition to release kinetics study in vitro. The efficiency of the photodynamic therapy (PDT) of MB photo-activated using 565 mW Light emitting diode (LED) 670 nm was evaluated in patients with resistant plaque psoriasis. The gel was evaluated in single blinded study. The patients were subjected to repeated sessions of irradiation, skin biopsies from each patient in the beginning and at the end of the sessions were taken for histopathological studies. Results showed the hydrogel was transparent nongritty and the drug uniformly dispersed with pH=7.2 and viscosity value=25.04 Pa. The drug content was found to be 99.4 +/- 0.15 %. Drug release was following zero order kinetics with rate constant K=0.348 +/- 0.01 and T(1/2) = 0.95 +/- 0.5 hours. Sixteen patients experienced complete clearance of their treated lesions. Skin appeared normal in color, texture, and pliability with no complications indicating the lack of skin sensitivity. Histopathological examinations showed nearly normal epidermis at the end of all sessions. The authors concluded that the prepared hydrogel was safe, stable, and very effective. The results are encouraging to accept MB as a photosensitizer for PDT and as a safe and effective method for treatment of selected cases of resistant localized psoriasis

  20. Functional inactivation of lymphocytes by methylene blue with visible light.

    PubMed

    Zhang, Bo; Cheng, Zhenzhen; Mo, Qin; Wang, Li; Wang, Xun; Wu, Xiaofei; Jia, Yao; Huang, Yuwen

    2015-10-01

    Transfusion of allogeneic white blood cells (WBCs) may cause adverse reactions in immunocompromised recipients, including transfusion-associated graft-versus-host disease (TA-GVHD), which is often fatal and incurable. In this study, the in vitro effect of methylene blue with visible light (MB + L) treatment on lymphocyte proliferation and cytokine production was measured to investigate whether MB + L can be used to prevent immune reactions that result from transfused lymphocytes. WBCs and 3 μM of MB were mixed and transferred into medical PVC bags, which were then exposed to visible light. Gamma irradiation was conducted as a parallel positive control. The cells without treatment were used as untreated group. All the groups were tested for the ability of cell proliferation and cytokine production upon stimulation. After incubation with mitogen phytohemagglutinin (PHA) or plate-bound anti-CD3 plus anti-CD28, the proliferation of MB + L/gamma-irradiation treated lymphocytes was significantly inhibited (P < 0.01) as compared to the untreated ones; the proliferation inhibitive rate of the MB + L group was even higher than that of gamma-irradiated cells (73.77% ± 28.75% vs. 44.72% ± 38.20%). MB + L treated cells incubated up to 7 days with PHA also showed no significant proliferation. The levels of TNF-α, IFN-γ, IL-6, IL-8, IL-10 and IL-1β present in the supernatant of MB + L treated lymphocytes upon stimulation were significantly lower than those of untreated lymphocytes. These results demonstrated that MB + L treatment functionally and irreversibly inactivated lymphocytes by inhibiting lymphocyte proliferation and the production of cytokines. MB + L treatment might be a promising method for the prevention of adverse immune responses caused by WBCs. PMID:26295729

  1. Complexation between carrageenan and methylene blue for sensor design

    NASA Astrophysics Data System (ADS)

    Ling, Yew Pei; Heng, Lee Yook

    2013-11-01

    Theoretical studies on the methylene blue (MB)-carrageenans complexation at solution and solid states have been carried out via ultraviolet spectrophotoscopy and reflectometry methods. The equilibrium constant (Ka) of the MBcarrageenans complexation follows the order of Iota > Lambda > Kappa carrageenans, which indicated Iota-carrageenan forms a stable complex. MB-carrageenan complexation reaction showed decrease in Ka value from 210.71 ppm-1 to 114.57 ppm-1 when the reaction temperature increased from 298 K to 323 K. Le Chatelier's principle and mass action law explained that the MB-carrageenan complexation was an exothermic reaction (ΔH=-18.54 kJmol-1) that release heat. Thus MB-carrageenan complex was less stable at high temperature and tend to dissociate into free MB and carrageenan molecules. It was also supported by the van't Hoff equation. The reaction is a spontaneous process (ΔG=-13.23 kJmol-1) where the randomness of the molecules reduced (ΔS=-17.83 Jmol-1K-1) due to complexation. Besides, linear regression of the concentration and absorption of the MB-carrageenan reaction obeys the Beer Lambert law, which elucidated that the complexation process was not affected by any concentration dependent factors such as aggregation and self-quenching. Moreover, linear Benesi Hilderbrend plot revealed that the interaction between MB and carrageenan was a reversible and stoichiometric reaction with 1:1 ratio. However, the molar extinction coefficient (ɛ) and molar adsorption coefficient (μa) of the MB-carrageenan complex were lower compared to free MB, described that the complex was less adsorptive. The sensor constructed based on these theoretical investigations showed response behavior that was similar with solution test as both have attraction for carrageenans in the sequence of Iota-, Lambda-, Kappa- carrageenans. Likewise, carrageenan sensor was more selective towards Iota-carrageenan than to Lambda- and Kappa-carrageenans, and no response observed when

  2. Urea enhances the photodynamic efficiency of methylene blue.

    PubMed

    Nuñez, Silvia C; Yoshimura, Tania M; Ribeiro, Martha S; Junqueira, Helena C; Maciel, Cleiton; Coutinho-Neto, Maurício D; Baptista, Maurício S

    2015-09-01

    Methylene blue (MB) is a well-known photosensitizer used mostly for antimicrobial photodynamic therapy (APDT). MB tends to aggregate, interfering negatively with its singlet oxygen generation, because MB aggregates lean towards electron transfer reactions, instead of energy transfer with oxygen. In order to avoid MB aggregation we tested the effect of urea, which destabilizes solute-solute interactions. The antimicrobial efficiency of MB (30 μM) either in water or in 2M aqueous urea solution was tested against a fungus (Candida albicans). Samples were kept in the dark and irradiation was performed with a light emitting diode (λ = 645 nm). Without urea, 9 min of irradiation was needed to achieve complete microbial eradication. In urea solution, complete eradication was obtained with 6 min illumination (light energy of 14.4 J). The higher efficiency of MB/urea solution was correlated with a smaller concentration of dimers, even in the presence of the microorganisms. Monomer to dimer concentration ratios were extracted from the absorption spectra of MB solutions measured as a function of MB concentration at different temperatures and at different concentrations of sodium chloride and urea. Dimerization equilibrium decreased by 3 and 6 times in 1 and 2M urea, respectively, and increased by a factor of 6 in 1M sodium chloride. The destabilization of aggregates by urea seems to be applied to other photosensitizers, since urea also destabilized aggregation of Meso-tetra(4-n-methyl-pyridyl)porphyrin, which is a positively charged porphyrin. We showed that urea destabilizes MB aggregates mainly by causing a decrease in the enthalpic gain of dimerization, which was exactly the opposite of the effect of sodium chloride. In order to understand this phenomenon at the molecular level, we computed the free energy for the dimer association process (ΔG(dimer)) in aqueous solution as well as its enthalpic component in aqueous and in aqueous/urea solutions by molecular dynamics

  3. The interaction between methylene blue and the cholinergic system

    PubMed Central

    Pfaffendorf, M; Bruning, T A; Batink, H D; van Zwieten, P A

    1997-01-01

    The inhibitory effects of methylene blue (MB) on different types of cholinesterases and [3H]-N-methylscopolamine ([3H]-NMS) binding to muscarinic receptors were studied. Human plasma from young healthy male volunteers, purified human pseudocholinesterase and purified bovine true acetylcholinesterase were incubated with acetylcholine and increasing concentrations of MB (0.1–100 μmol l−1) in the presence of the pH-indicator m-nitrophenol for 30 min at 25°C. The amount of acetic acid produced by the enzymatic hydrolysis of acetylcholine was determined photometrically. Rat cardiac left ventricle homogenate was incubated with [3H]-NMS and with increasing concentrations of MB (0.1 nmol l−1–100 μmol l−1) at 37°C for 20 min. The binding of [3H]-NMS to the homogenate was quantified by a standard liquid scintillation technique. MB inhibited the esterase activity of human plasma, human pseudocholinesterase and bovine acetylcholinesterase concentration-dependently with IC50 values of 1.05±0.05 μmol l−1, 5.32±0.36 μmol l−1 and 0.42±0.09 μmol l−1, respectively. MB induced complete inhibition of the esterase activity of human plasma and human pseudocholinesterase, whereas bovine acetylcholinesterase was maximally inhibited by 73±3.3%. MB was able to inhibit specific [3H]-NMS binding to rat cardiac left ventricle homogenate completely with an IC50 value of 0.77±0.03 μmol l−1, which resulted in a Ki value for MB of 0.58±0.02 μmol l−1. In conclusion, MB may be considered as a cholinesterase inhibitor with additional, relevant affinity for muscarinic binding sites at concentrations at which MB is used for investigations into the endothelial system. In our opinion these interactions between MB and the cholinergic system invalidate the use of MB as a tool for the investigation of the L-arginine-NO-pathway, in particular when muscarinic receptor stimulation is involved. PMID:9298533

  4. Synthetic method and biological activities of cis-fused alpha-methylene gamma-lactones.

    PubMed

    Higuchi, Yohsuke; Shimoma, Fumito; Ando, Masayoshi

    2003-06-01

    A reliable method was developed for the synthesis of cis-fused alpha-methylene gamma-lactones via alpha-methyl gamma-lactones. Bromination of alpha-methyl gamma-lactones with LDA/CBr(4) or TMSOTf/PTAB and successive dehydrobromination with DBU or TBAF of the resulting alpha-bromo-alpha-methyl gamma-lactones gave the desired alpha-methylene gamma-lactones in high yield. This method was successfully applied to the synthesis of biologically active compounds. alpha-Methylene gamma-lactone derivatives 1c, 2c, 4c, and 17 showed cell growth inhibitory activity to P388 lymphocytic leukemia. They also showed significant activities to crop diseases. Thus, alpha-methylene gamma-lactone 1c showed preventive activity in controlling scab of apple caused by Venturia inaequalis. alpha-Methylene gamma-lactones 2c, 4c, 17, and 18 also showed significant preventive activities in controlling damping off of cucumber caused by Pythium aphanidermatum.

  5. Heinz-body hemolytic anemia associated with ingestion of methylene blue in a river otter.

    PubMed

    Narurkar, Neelesh S; Thomas, Jennifer S; Phalen, David N

    2002-02-01

    Heinz-body hemolytic anemia and nephrosis associated with hemoglobinuria were diagnosed in a North American river otter. Fluids were administered, and the signs of renal failure improved immediately. Severe anemia developed, and the otter received a semisynthetic hemoglobin product to maintain the oxygen-carrying capacity of the blood until a blood transfusion could be given. Immediate clinical improvement was observed following hemoglobin administration, and adverse effects were not seen. Six days after admission, the otter began to produce its own RBC and recovered without complications. The Heinz-body anemia was determined to be caused by methylene blue that was in the water of minnows consumed by the otter the night before it became ill. Methylene blue is a common ingredient in products used to extend the life of bait fish. Bait fish kept in water treated with methylene blue should not be used as food for fish-eating animals.

  6. A Study for Health Hazard Evaluation of Methylene Chloride Evaporated from the Tear Gas Mixture

    PubMed Central

    Chung, Eun-Kyo; Yi, Gwang-Yong; Chung, Kwang-Jae; Shin, Jung-Ah; Lee, In-Seop

    2010-01-01

    This study explored the health hazard of those exposed to methylene chloride by assessing its atmospheric concentration when a tear gas mixture was aerially dispersed. The concentration of methylene chloride ranged from 311.1-980.3 ppm (geometric mean, 555.8 ppm), 30 seconds after the dispersion started. However, the concentration fell rapidly to below 10 ppm after dispersion was completed. The concentration during the dispersion did not surpass the National Institute for Occupational Safety and Health 'immediately dangerous to life or health' value of 2,300 ppm, but did exceed the American Conference of Governmental Industrial Hygienists excursion limit of 250 ppm. Since methylene chloride is highly volatile (vapor pressure, 349 mmHg at 20℃), the postdispersion atmospheric concentration can rise instantaneously. Moreover, the o-chlorobenzylidenemalononitrile formulation of tear gas (CS gas) is an acute upper respiratory tract irritant. Therefore, tear gas mixtures should be handled with delicate care. PMID:22953168

  7. Adsorption of chlorophenol, chloroaniline and methylene blue on fuel oil fly ash.

    PubMed

    Andini, Salvatore; Cioffi, Raffaele; Colangelo, Francesco; Montagnaro, Fabio; Santoro, Luciano

    2008-09-15

    Fuel oil fly ash has been tested as low-cost carbon-based adsorbent of 2-chlorophenol (CP), 2-chloroaniline (CA) and methylene blue (MB) from aqueous solutions. In all the cases the adsorption was found to be of cooperative type. Different adsorption capacities were found for the three organics. Specifically, it was highest for 2-chlorophenol, reaching about 70 mg g(-1), and quite lower in the other two cases, that is about 47 and 36 mg g(-1) for methylene blue and 2-chloroaniline, respectively. Varying the initial pH and adding KCl were found to have different effects on the adsorption of the three organics. In particular, the presence of other ions had no effect on the adsorption of methylene blue, adverse effect in the case of 2-chlorophenol and enhancing effect in the case of 2-chloroaniline.

  8. Utility of methylene blue for the reversal of excessive levels of methemoglobin

    SciTech Connect

    Vick, J.; Von Bredow, J.; Brown, L.; Kaminskis, A.; Bossone, C.

    1993-05-13

    Many new prophylactic and therapeutic compounds are being studied as potential sources of methemoglobin useful in counteracting the lethal effects of cyanide intoxication. The formation of methemoglobin also leads to a reduction in the blood oxygen carrying capacity which may, in extreme cases, lead to lethal consequences. The i.v. administration of Methylene blue rapidly reverses methemoglobin to hemoglobin. Unanticipated high levels of methemoglobin (65 - 85%) in three sheep exposed to propiophenone derivatives led to a lethal outcome in one untreated sheep and complete recovery in two sheep which were treated with 3.0 mg/kg methylene blue i.v. methemoglobin was reduced to safe levels within minutes following administration. A similar exposure of dogs to propriophenone derivatives led to high levels (77 - 78%) of methemoglobin which were readily reversed following the intravenous administration of the same dose of methylene blue.

  9. Synthesis of mesoporous TiO2-curcumin nanoparticles for photocatalytic degradation of methylene blue dye.

    PubMed

    Abou-Gamra, Z M; Ahmed, M A

    2016-07-01

    Herein, we demonstrate a facile route for synthesis a new photocatalyst based on TiO2-curcumin nanoparticles for photodegradation of methylene blue dye under UV and visible light irradiation. The photocatalyst was prepared by sol-gel method using chitosan as biodegradable polymer. The crystalline and the nanostructure were characteristic X-ray diffraction [XRD], adsorption-desorption isotherm and high resolution transmission electron microscopy [HRTEM]. However, the optical features of the samples were investigated by a UV-visible spectrophotometer. It is obvious to notice the removal of the majority of methylene blue dye on a pure titania surface via adsorption mechanism owing to the high surface area and to the organized mesoporous nature of the solid sample. Incorporation of curcumin on titania surface changes the removal direction from adsorption to the photocatalytic pathway. Various photocatalytic experiments were performed to investigate the influence of initial dye concentration, weight of catalyst, stirring and light intensity on the photocatalytic degradation of methylene blue as primary pollutant model. Chemical oxygen demand [COD] test confirms the complete degradation of methylene blue dye. The exceptional photocatalytic reactivity of titania-curcumin nanoparticles is referred to reduction in band gap energy and to the facility of electron transfer from II* curcumin energy level to titania conduction band which increases the concentration of reactive oxygen superoxide radicals which in turn prevents the electron-hole recombination. The effect of various scavengers on the methylene blue dye degradation was investigated using ethanol, ascorbic acid and methyl viologen. The results have pointed out that O2(-) and HO(.) are considered the main active species in the degradation process. A plausible pathway and mechanism for the photocatalytic degradation of methylene blue by titania-curcumin nanoparticles were illustrated.

  10. Viral Inactivation of Human Osteochondral Grafts with Methylene Blue and Light

    PubMed Central

    Zhao, Zhixing; Call, Gazell M.; Gao, Jizong; Yao, Jian Q.

    2014-01-01

    Objective: Cartilage injury is one of the most common disorders of synovial joints. Fresh osteochondral allografts are becoming a standard treatment; however, they are supply constrained with a potential risk of disease transmission. There are no known virucidal processes available for osteochondral allografts and most methods presently available are detrimental to cartilage. Methylene blue light treatment has been shown to be successful in the literature for viral inactivation of fresh frozen plasma. The purpose of this study was to determine the capacity of methylene blue light treatment to inactivate a panel of clinically relevant viruses inoculated onto osteochondral allografts. Design: Osteochondral grafts recovered from human cadaveric knees were inoculated with one of the following viruses: bovine viral diarrhea virus (BVDV), hepatitis A virus (HAV), human immunodeficiency virus type 1 (HIV-1), porcine parvovirus (PPV), and pseudorabies virus (PrV). The samples were processed through a methylene blue light treatment, which consisted of an initial soak in nonilluminated circulating methylene blue at ambient temperature, followed by light exposure with circulating methylene blue at cool temperatures. The final titer was compared with the recovery control for the viral log reduction. Results: HIV-1, BVDV, and PrV were reduced to nondetectable levels while HAV and PPV were reduced by 3.1 and 5.6 logs, respectively. Conclusions: The methylene blue light treatment was effective in reducing (a) enveloped DNA and RNA viruses to nondetectable levels and (b) nonenveloped DNA and RNA viruses of inoculated human osteochondral grafts by 3.1 to 5.6 logs. This study demonstrates the first practical method for significantly reducing viral load in osteochondral implants. PMID:26069682

  11. Aggregation of 1,3,7-trimethylxanthine with methylene blue in aqueous solution

    NASA Astrophysics Data System (ADS)

    Baranovskii, S. F.; Bolotin, P. A.; Evstigneev, M. P.

    2006-03-01

    We have studied self-association of aromatic molecules of the thiazine dye methylene blue in aqueous solution, using a dimer model. We have determined the dimerization equilibrium constant for the dye molecules KD = 3900 ± 800 M-1 at T = 293 K. We have decomposed the experimental spectrum into dimer and monomer components. Using the ratio of the molar absorption coefficients for two absorption bands of the dimer spectrum, we obtained the “average” value of the angle between the electronic transition moments of the molecules in the dimers, α = 48°. We have studied heteroassociation of methylene blue (MB) and 1,3,7-trimethylxanthine (caffeine) molecules in aqueous solution. We have calculated the heteroassociation constant as 200 ± 34 M-1. We conclude that heteroassociation of methylene blue and caffeine molecules leads to a lower effective dye concentration in solution, which hypothetically may affect its biological activity. We have determined the values of the Gibbs free energy, the enthalpy, and the entropy for dimerization of methylene blue molecules: ΔG293 = -(20 ± 3) kJ/mol, ΔH = -(25 ± 9) kJ/mol, Δ S293 = -(17 ± 6) J/mol·K; and for methylene blue-caffeine heteroassociation: ΔG293 = -(13 ± 3) kJ/mol, ΔH = -(14 ± 10) kJ/mol, ΔS293 = -(2.4 ± 0.2) J/mol·K, respectively. We have shown that the methylene blue aggregates and the heteroassociates with caffeine are predominantly stabilized by dispersion interactions between the chromophore molecules in the associates.

  12. Synthesis of mesoporous TiO2-curcumin nanoparticles for photocatalytic degradation of methylene blue dye.

    PubMed

    Abou-Gamra, Z M; Ahmed, M A

    2016-07-01

    Herein, we demonstrate a facile route for synthesis a new photocatalyst based on TiO2-curcumin nanoparticles for photodegradation of methylene blue dye under UV and visible light irradiation. The photocatalyst was prepared by sol-gel method using chitosan as biodegradable polymer. The crystalline and the nanostructure were characteristic X-ray diffraction [XRD], adsorption-desorption isotherm and high resolution transmission electron microscopy [HRTEM]. However, the optical features of the samples were investigated by a UV-visible spectrophotometer. It is obvious to notice the removal of the majority of methylene blue dye on a pure titania surface via adsorption mechanism owing to the high surface area and to the organized mesoporous nature of the solid sample. Incorporation of curcumin on titania surface changes the removal direction from adsorption to the photocatalytic pathway. Various photocatalytic experiments were performed to investigate the influence of initial dye concentration, weight of catalyst, stirring and light intensity on the photocatalytic degradation of methylene blue as primary pollutant model. Chemical oxygen demand [COD] test confirms the complete degradation of methylene blue dye. The exceptional photocatalytic reactivity of titania-curcumin nanoparticles is referred to reduction in band gap energy and to the facility of electron transfer from II* curcumin energy level to titania conduction band which increases the concentration of reactive oxygen superoxide radicals which in turn prevents the electron-hole recombination. The effect of various scavengers on the methylene blue dye degradation was investigated using ethanol, ascorbic acid and methyl viologen. The results have pointed out that O2(-) and HO(.) are considered the main active species in the degradation process. A plausible pathway and mechanism for the photocatalytic degradation of methylene blue by titania-curcumin nanoparticles were illustrated. PMID:27107333

  13. Bone resorption, metastasis, and diphosphonates

    SciTech Connect

    Garattini, S.

    1985-01-01

    This book contains 17 selections. Some of the titles are: Radiotherapy of Bone Lesions; Methodological Problems; Treatment of Bone Metastasis with Antiresorptive Drugs; Control of Bone Cancer Pain; and Chemotherapy of Bone Metastases.

  14. Effect of dimethyl sulfoxide addition on ultrasonic degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Shimakage, Kaho; Kobayashi, Daisuke; Naya, Masakazu; Matsumoto, Hideyuki; Shimada, Yuichiro; Otake, Katsuto; Shono, Atsushi

    2016-07-01

    The ultrasonic degradation of methylene blue was carried out in the absence and presence of dimethyl sulfoxide (DMSO) as a radical scavenger for various frequencies, and the effects of DMSO addition on the degradation rate constant estimated by assuming first-order kinetics were investigated. The degradation reaction rate decreased with DMSO addition, and hydroxyl radicals were observed to play important roles in the degradation of methylene blue. However, the degradation reaction did not stop with DMSO addition, and the degradation rate constant in the presence of DMSO was not affected by ultrasonic frequency.

  15. 76 FR 14432 - Methylene Chloride Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    ... Paperwork Reduction Act of 1995 (44 U.S.C. 3506 et seq.) and Secretary of Labor's Order No. 4-2010 (75 FR... requirements specified by the Methylene Chloride Standard (29 CFR 1910.1052). DATES: Comments must be submitted... entitled ``Methylene Chloride'' (MC) (29 CFR 1910.1052; the ``Standard'') protects workers from the...

  16. Graphene oxide functionalized with methylene blue and its performance in singlet oxygen generation

    SciTech Connect

    Wojtoniszak, M.; Rogińska, D.; Machaliński, B.; Drozdzik, M.; Mijowska, E.

    2013-07-15

    Graphical abstract: - Highlights: • Adsorption of methylene blue (MB) on graphene oxide (GO). • Characterization of graphene oxide–methylene blue nanocomposite (MB–GO). • Examination of MB–GO efficiency in singlet oxygen generation (SOG). • MB–GO performs higher SOG efficiency than pristine MB. - Abstract: Due to unique electronic, mechanical, optical and structural properties, graphene has shown promising applications in many fields, including biomedicine. One of them is noninvasive anticancer therapy – photodynamic therapy (PDT), where singlet oxygen (SO), generated under the irradiation of light with appropriate wavelengths, kills cancer cells. In this study, authors report graphene oxide (GO) noncovalent functionalization with methylene blue (MB). MB molecules underwent adsorption on the surface of GO. Detailed characterization of the obtained material was carried out with UV–vis spectroscopy, Raman spectroscopy, FT-IR spectroscopy, and confocal laser scanning microscopy. Furthermore, its performance in singlet oxygen generation (SOG) under irradiation of laser with excitation wavelengths of 785 nm was investigated. Interestingly, GO functionalized with MB (MB–GO) showed enhanced efficiency in singlet oxygen generation compared to pristine MB. The efficiency in SOG was detected by photobleaching of 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABMDMA). These results indicate the material is promising in PDT anticancer therapy and further in vitro and in vivo studies are required.

  17. Comparative pharmacokinetics of oral and intravenous ifosfamide/mesna/methylene blue therapy.

    PubMed

    Aeschlimann, C; Küpfer, A; Schefer, H; Cerny, T

    1998-09-01

    Oral treatment with ifosfamide results in dose-limiting encephalopathy. Methylene blue is effective in reversal and prophylaxis of this side effect. In the present study, the pharmacokinetics of ifosfamide after iv and po therapy in combination with prophylactic administration of methylene blue were investigated. Nine patients with metastatic non-small cell lung cancer were treated by a combination of ifosfamide (3 days), sodium 2-mercaptoethane sulfonate (4 days), and etoposide (8 days). Cycles were repeated every 28 days. Ifosfamide was administered orally, with the exception of one of the first two cycles, when it was administered as a short infusion (randomly assigned). The patients received methylene blue in doses of 50 mg po 3 times daily; an initial dose of 50 mg was given the evening before chemotherapy. Urine samples were collected over the entire treatment period, and concentrations of ifosfamide and its major metabolite, 2-chloroethylamine, were measured by gas liquid chromatography. By the same technique, 2- and 3-dechloroethylifosfamide were determined in plasma and urine. Overall alkylating activity in urine was assayed by reaction of the alkylating metabolites with 4-(4'-nitrobenzyl)-pyridine. The chemotherapeutic regimen was well-tolerated by all of the patients studied. There was no evidence of a shift in the metabolic pattern dependent on the route of administration. From the data, we conclude that methylene blue has a neuroprotective effect and that the pharmacokinetics of ifosfamide are not influenced by its comedication.

  18. The feasibility of using methylene blue sensitized polyvinylalcohol film as a linear polarizer

    SciTech Connect

    Jyothilakshmi, K.; Anju, K. S.; Arathy, K.; John, Beena Mary; Krishna, P. B.; Sruthi, C. T.; Chacko, Maria

    2014-01-28

    Linear light polarizing films selectively transmit radiations vibrating along an electromagnetic radiation vector and selectively absorb radiations vibrating along a second electromagnetic radiation vector. It happens according to the anisotropy of the film . In the present study the polarization effects of methylene blue sensitized polyvinyl alcohol is investigated. The polarization effects on the dye concentration, heating and stretching of film also are evaluated.

  19. IRIS Toxicological Review of Dichloromethane (Methylene Chloride) (Interagency Science Consultation Draft)

    EPA Science Inventory

    On March 31, 2010, the draft IRIS Toxicological Review of Dichloromethane (Methylene Chloride) external review draft document and the charge to external peer reviewers were released for public review and comment. The draft document and the charge to external peer reviewers were r...

  20. 21 CFR 520.154b - Bacitracin methylene disalicylate and streptomycin sulfate powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Bacitracin methylene disalicylate and streptomycin sulfate powder. 520.154b Section 520.154b Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.154b Bacitracin...

  1. Rapid alkaline methylene blue supravital staining for assessment of anterior segment infections

    PubMed Central

    Kiuchi, Katsuji

    2016-01-01

    Purpose To present the Löffler’s alkaline methylene blue technique of staining eye discharges in eyes with anterior segment infections. Method The Löffler’s alkaline methylene blue staining method is a simple staining technique that can be used to differentiate bacterial, viral, and fungal infections. It is a cationic dye that stains cells blue because the positively charged dye is attracted to negatively charged particles such as polyphosphates, DNAs, and RNAs. Specimens collected from patients by swabbing are smeared onto microscope slides and the methylene blue solution is dropped on the slide. The slide is covered with a glass cover slip and examined under a microscope. The entire time from the collection to the viewing is about 30 seconds. Results Histopathological images of the conjunctival epithelial cells and neutrophils in eye discharges were dyed blue and the nuclei were stained more intensely blue. Bacterial infections consisted mainly of neutrophils, and viral infections consisted mainly of lymphocytes. Conclusions Löffler’s alkaline methylene blue staining can be done in about 30 seconds for diagnosis. Even though this is a one color stain, it is possible to infer the cause of the infection by detection of the absence of bacteria and/or fungi in context of the differential distribution of neutrophils and lymphocytes. PMID:27784986

  2. SOURCE CHARACTERIZATION AND CONTROL TECHNOLOGY ASSESSMENT OF METHYLENE CHLORIDE EMISSIONS FROM EASTMAN KODAK COMPANY, ROCHESTER, NY

    EPA Science Inventory

    The report gives results of an assessment of potential control technologies for methylene chloride (also known as dichloromethane or DCM) emission sources at Eastman Kodak Company's Kodak Park facility in Rochester, NY. DCM is a solvent used by Kodak in the manufacture of cellulo...

  3. Process for crosslinking methylene-containing aromatic polymers with ionizing radiation

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L. (Inventor); Havens, Stephen J. (Inventor)

    1990-01-01

    A process for crosslinking aromatic polymers containing radiation-sensitive methylene groups (-CH2-) by exposing the polymers to ionizing radiation thereby causing crosslinking of the polymers through the methylene groups is described. Crosslinked polymers are resistant to most organic solvents such as acetone, alcohols, hydrocarbons, methylene, chloride, chloroform, and other halogenated hydrocarbons, to common fuels and to hydraulic fluids in contrast to readily soluble uncrosslinked polymers. In addition, the degree of crosslinking of the polymers depends upon the percentage of the connecting groups which are methylene which ranges from 5 to 50 pct and preferably from 25 to 50 pct of the connecting groups, and is also controlled by the level of irradiation which ranges from 25 to 1000 Mrads and preferably from 25 to 250 Mrads. The temperature of the reaction conditions ranges from 25 to 200 C and preferably at or slightly above the glass transition temperature of the polymer. The crosslinked polymers are generally more resistant to degradation at elevated temperatures such as greater than 150 C, have a reduced tendency to creep under load, and show no significant embrittlement of parts fabricated from the polymers.

  4. Photo-degradation of methylene blue using Ta-doped ZnO nanoparticle

    SciTech Connect

    Kong Jizhou; Li Aidong; Li Xiangyu; Zhai Haifa; Zhang Wenqi; Gong Youpin; Li Hui; Wu Di

    2010-06-15

    A photocatalyst of Ta-doped ZnO was prepared by a modified Pechini-type method. The structural, morphological properties and photocatalytic activity of 1 mol % Ta-doped ZnO samples annealed at different temperatures were characterized. The photo-oxidation of methylene blue under the visible-light irradiation followed the pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. It is found that the photocatalysis of 1% Ta-doped ZnO annealed at 700 {sup o}C showed excellent performance of the photodegradation of methylene blue, which was attributed to a competitive trade-off among the crystallinity, surface hydroxyl groups, and specific surface area. The processing parameter such as the pH value also played an important role in tuning the photocatalytic activity. The maximum photodecomposed rate was achieved at pH=8, and an novel model about the absorption of methylene blue on the surface of the catalysts was proposed. - Graphical abstract: This model describes the adsorption between the amphoteric behavior of the metal oxide and the cationic dye methylene blue (MB) on the surface of the catalyst at the acidic and alkaline condition.

  5. 40 CFR 721.10581 - Brominated polyurethane prepolymers of methylene diphenyl diisocyanate (MDI) (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Brominated polyurethane prepolymers of... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10581 Brominated polyurethane... polyurethane prepolymers of methylene diphenyl diisocyanate (MDI) (PMNs P-10-524 and P-10-525) are subject...

  6. 40 CFR 721.10581 - Brominated polyurethane prepolymers of methylene diphenyl diisocyanate (MDI) (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Brominated polyurethane prepolymers of... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10581 Brominated polyurethane... polyurethane prepolymers of methylene diphenyl diisocyanate (MDI) (PMNs P-10-524 and P-10-525) are subject...

  7. Visible light induced photobleaching of methylene blue over melamine-doped TiO2 nanocatalyst

    EPA Science Inventory

    TiO2 doping with N-rich melamine produced a stable, active and visible light sentisized nanocatalyst that showed a remarkable efficiency towards the photobleaching of a model compound – methylene blue (MB) in aqueous solution. The photobleaching followed a mixed reaction order ki...

  8. Citrus pectin derived porous carbons as a superior adsorbent toward removal of methylene blue

    NASA Astrophysics Data System (ADS)

    Zhang, Wenlin; Zhang, Lian Ying; Zhao, Xi Juan; Zhou, Zhiqin

    2016-11-01

    An adsorbent, citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward removal of methylene blue, was synthesized by a facile zinc chloride activation approach in this study. The materials hold a great potential for treatment of dye wastewater.

  9. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... 500.27 Section 500.27 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cats or dogs. (1)(i) It has been demonstrated that two orally administered urinary antiseptic-antispasmodic preparations that contained methylene blue cause Heinz body hemolytic anemia in cats when...

  10. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... 500.27 Section 500.27 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cats or dogs. (1)(i) It has been demonstrated that two orally administered urinary antiseptic-antispasmodic preparations that contained methylene blue cause Heinz body hemolytic anemia in cats when...

  11. Heterogeneous photocatalysis of methylene blue over titanate nanotubes: effect of adsorption.

    PubMed

    Xiong, Lin; Sun, Weiling; Yang, Ye; Chen, Cheng; Ni, Jinren

    2011-04-01

    Titanate nanotubes were synthesized with hydrothermal reaction using TiO(2) and NaOH as the precursors and subsequent calcination at 400°C for 2h. The products were characterized with SEM and XRD. Adsorption and photocatalysis of methylene blue over titanate nanotubes and TiO(2) were investigated. The results indicated that titanate nanotubes exhibited a better photocatalytic degradation of methylene blue in a simultaneous adsorption and photodegradation system than that in equilibrium adsorption followed by a photodegradation system, whereas TiO(2) showed no significant differences in photocatalytic activity in the two systems. The methylene blue overall removal efficiency over TNTs in the first system even exceeded that over TiO(2). The different catalytic performances of titanate nanotubes in the two systems were tentatively attributed to different effects of adsorption of methylene blue, i.e., the promoting effect in the former and the inhibition effect in the latter. Decantation experiments showed that the titanate nanotube photocatalyst could be easily separated from the reaction medium by sedimentation. Thus titanate nanotubes with high sedimentation rates and concurrent adsorption represent a new catalyst system with a strong potential for commercial applications.

  12. 21 CFR 520.154b - Bacitracin methylene disalicylate and streptomycin sulfate powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.154b Bacitracin methylene disalicylate and streptomycin sulfate powder. (a..., Proteus spp., Staphylococcus spp., and Streptococcus spp., and for the symptomatic treatment of...

  13. 21 CFR 520.154b - Bacitracin methylene disalicylate and streptomycin sulfate powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.154b Bacitracin methylene disalicylate and streptomycin sulfate powder. (a..., Proteus spp., Staphylococcus spp., and Streptococcus spp., and for the symptomatic treatment of...

  14. 21 CFR 520.154b - Bacitracin methylene disalicylate and streptomycin sulfate powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Bacitracin methylene disalicylate and streptomycin sulfate powder. 520.154b Section 520.154b Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.154b Bacitracin...

  15. 21 CFR 177.1660 - Poly (tetra-methylene tereph-thalate).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Poly (tetra-methylene tereph-thalate). 177.1660 Section 177.1660 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated...

  16. [Sensitive determination of Bi3+ by spectrofluorimetry based on graphene oxide-methylene blue system].

    PubMed

    Zhai, Qiu-ge; Guo, Peng; Zhou, Lin; Liu, Yan-ming

    2014-08-01

    Graphene oxide was prepared by the modified Hummers method and characterized by field emission scanning electron microscopy. The interaction of graphene with methylene blue was studied by UV absorption, the intensity of two main absorption peaks of methylene blue decreased significantly after the fluorescence was quenched, and the energy transfer didn't occur because the overlap of the absorption spectrum of GO and the emission spectrum of MB is too small. Therefore, the fluorescence quenching of MB and GO was static. When adding a certain amount of Bi3+ in the graphene-methylene blue system, Bi3+ replaces the methylene blue from the graphene-methylene blue complexes because Bi3+ has the smaller volume and is more positively charged. The methylene blue therefore dissociates from the GO-MB complexes, resulting in the recovery of fluorescence of the system. Furthermore, the fluorescence of the system increases with the increase in the amount of Bi3+ due to the enhanced amount of MB in the system. A novel spectrofluorimetric method was therefore developed for the sensitive determination of Bi3+. Some parameters including the concentration of methylene blue, the amount of graphene oxide, the amount of nitric acid and the sequence of reagent adding were optimized to obtain higher sensitivity. The fluorescence of the system was detected at an emission wavelength of 667 nm with excitation at 690 nm. Under the optimized conditions, the concentration of Bi3+ showed good linear relationships with the fluorescence intensity in the range of 0.5-100 micromol x L(-1), with correlation coefficients of r = 0.9955. The limits of detection for Bi3+ was 1.0 x 10(-8) mol x L(-1) (S/N=3). The selectivity of the proposed method was evaluated and the results showed that 1000-fold K+, Ca+, Na+, Mg2+, Cu2+; 100-fold Fe3+, Be2+, SiO2- Al3+, Ni2+, Sb3+, NO3-, Cl-, F-, and 20-fold Pb2+, Hg2+, Cd2+ had negligible interference with the determination of Bi3+. The method has advantages of

  17. Mortality of workers exposed to methylene chloride employed at a plant producing cellulose triacetate film base.

    PubMed Central

    Tomenson, J A; Bonner, S M; Heijne, C G; Farrar, D G; Cummings, T F

    1997-01-01

    OBJECTIVE: To study mortality among 1785 employees of a factory that produced cellulose triacetate film base at Brantham in the United Kingdom. Also, to investigate patterns of mortality after exposure to methylene chloride; in particular, mortality from liver and biliary tract cancer, lung cancer, pancreatic cancer, and cardiovascular disease. SUBJECTS AND METHODS: All male employees with a record of employment at the film factory in 1946-88. A total of 1473 subjects worked in jobs that entailed exposure to methylene chloride. The mean duration of exposure was nine years at 19 ppm (eight hour time weighted average). RESULTS: In the cohort, 334 deaths were identified up to 31 December 1994. Mortalities for the cohort were compared with national and local rates and expressed as standardised mortality ratios (SMR). In the subcohort of workers exposed to methylene chloride, substantially reduced mortalities compared with national and local rates were found for all causes, all cancers, and the principal cancer sites of interest. The significantly reduced lung cancer mortalities in exposed workers (SMR 48) seemed to reflect the restrictions on smoking at the workplace. In contrast, mortality from ischaemic heart disease in exposed workers, although lower than national rates (SMR 92), was slightly increased compared with local rates. However, mortality from ischaemic heart disease was lower in active employees (SMR 83) where a direct effect of exposure to methylene chloride should be concentrated. No in service mortality due to ischaemic heart disease was found in workers with the highest cumulative exposure (> or = 800 ppm-years). CONCLUSIONS: The study provided no indication that employment at the plant, or exposure to methylene chloride, had adversely affected the mortalities of workers. PMID:9282122

  18. CNS toxicity involving methylene blue: the exemplar for understanding and predicting drug interactions that precipitate serotonin toxicity.

    PubMed

    Gillman, P Ken

    2011-03-01

    Methylene blue has only recently been noted to cause severe central nervous system toxicity. Methylene blue is used for various conditions, including, intravenously, in methemoglobinemia, vasoplegia and as an aid to parathyroidectomy (at doses of 1-7.5 mg kg(-1)). This review of the current evidence concludes that 13 of 14 of the reported cases of CNS toxicity were serotonin toxicity that met the Hunter Serotonin Toxicity Criteria. That has important preventative and treatment implications. Serotonin toxicity is precipitated by the monoamine oxidase inhibitor (MAOI) property of methylene blue interacting with serotonin reuptake inhibitors. Serotonin toxicity is reviewed, using the lessons inherent in the methylene blue story and experience, to illustrate how the mechanisms and potency of serotonergic drugs interact to determine severity. Recent human data showed that an intravenous dose of only 0.75 mg kg(-1) of methylene blue produced a peak plasma concentration of 500 ng ml(-1) (1.6 µM), indicating that the concentration in the central nervous system reaches a level that inhibits monoamine oxidase A. That is consonant with the actual occurrence of severe serotonin toxicity in humans at the dose of only 1 mg kg(-1). It seems that all proposed uses of methylene blue entail levels that block monoamine oxidase, so cessation of serotonin reuptake inhibitors should be very carefully considered before using methylene blue.

  19. [Ectopic mediastinal parathyroid tumor resected by video-assisted thoracic surgery with intraoperative methylene blue infusion; report of a case].

    PubMed

    Okagawa, Takehiko; Hiramatsu, Yoshinori

    2014-03-01

    We report a surgical case of ectopic mediastinal parathyroid tumor resected by video-assisted thoracic surgery with intraoperative methylene blue infusion. It is often difficult to detect ectopic mediastinal parathyroid tumor during the operation because the tumor is soft, small and buried under mediastinal tissue. After methylene blue 4 mg/kg intravenously administration, the tumor was gradually dyed blue and easily detected and resected by video-assisted thoracic surgery. It is useful of methylene blue for detection of ectopic mediastinal parathyroid tumor.

  20. Fast-response humidity-sensing films based on methylene blue aggregates formed on nanoporous semiconductor films

    NASA Astrophysics Data System (ADS)

    Ishizaki, Ryota; Katoh, Ryuzi

    2016-05-01

    We prepared fast-response colorimetric humidity-sensing (vapochromic) films based on methylene blue adsorption onto nanoporous semiconductor (TiO2, Al2O3) films. Color changes caused by changes of humidity could be easily identified visually. A characteristic feature of the vapochromic films was their fast response to changes of humidity. We found that the response began to occur within 10 ms. The response was rapid because all the methylene blue molecules attached to the nanoporous semiconductor surface were directly exposed to the environment. We also deduced that the color changes were caused by structural changes of the methylene blue aggregates on the surface.

  1. Comparative study of calcium alginate, activated carbon, and their composite beads on methylene blue adsorption.

    PubMed

    Hassan, A F; Abdel-Mohsen, A M; Fouda, Moustafa M G

    2014-02-15

    Three adsorbents, calcium alginate beads (AB), sodium hydroxide activated carbon based coconut shells (C), and calcium alginate/activated carbon composite beads (ACB) were prepared. Their textural properties were characterized by N2-adsorption at -196°C and scanning electron microscopy. The porosity, surface area and total pore volume of C>ACB>AB, but AB adsorbent was more acidic function groups more than the other adsorbents. Adsorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature and initial concentration of methylene blue. Methylene blue adsorption on C, AB and ACB was observed at pH>6 to avoid the competition of H(+). The amount of dye adsorbed increases as the adsorbent dosage increase. Adsorption of dye follows pseudo-second order mechanism. Thermodynamic studies show spontaneous and endothermic nature of the overall adsorption process.

  2. [Study on the inclusion behavior of cucurbit [7] uril with methylene blue by spectrofluorometric titrations].

    PubMed

    Yu, Hua-peng; Sun, Jun-yong; Wu, Lian; Xu, Hong-wei; Wang, Lun; Zhou, Yun-you

    2009-04-01

    The characteristics of host-guest complexation between cucurbit [7] uril (CB7) and methylene blue (MB) were investigated by fluorescence spectrometry in acetate buffer solution at room temperature. It was found that the fluorescence intensity of methylene blue regularly increased upon the addition of cucurbit [7] uril accompanying with a blue-shift of the position of the emission maximum. The results indicate the formation of complex between CB7 and MB at a 1 : 1 complex stoichiometry and the association constant was calculated by applying a deduced equation. 1H NMR spectra were applied to to complement the fluorescence work to verify the formation of the complex. From the temperature dependence of the equilibrium constants, thermodynamics parametersH andS values were obtained, indicating an enthalpic driving force for complexation. The possible interaction mechanism was also discussed. This work may extend the application range of cucurbit [7] uril in biochemistry and pharmaceutical analysis.

  3. Methylene chloride exposure in furniture-stripping shops: ventilation and respirator use practices.

    PubMed

    Hall, A H; Rumack, B H

    1990-01-01

    Four cases of serious methylene chloride (dichloromethane) poisoning, including fatalities, in small-scale furniture-stripping shops were reported to the Rocky Mountain Poison and Drug Center between 1984 and 1988. Adequate ventilation systems and use of recommended respirators may seem impractical or overly expensive to the operators of such shops. Twenty-one shops in the metropolitan Denver, Colorado area were surveyed. A half-facepiece respirator with organic vapor cartridges was worn at least part-time in 14 of 21 shops; none was worn in 7. In 10 of 21 shops, workers had experienced dizziness, headache, or nausea when stripping furniture. Current safety practices in small-scale furniture-stripping shops may be inadequate to keep methylene chloride exposure levels in compliance with latest recommendations, and serious or fatal overexposure can occur.

  4. Effect of methylene group insertions on the structural rigidity of Aib containing helices.

    PubMed

    Duley, Anju; Gowda, Vasantha; Ganjiwale, Anjali; Raghothama, Srinivasarao; Ramanathan, Gurunath

    2015-11-01

    Nonprotein amino acids are being extensively used in the design of synthetic peptides to create new structure mimics. In this study we report the effect of methylene group insertions in a heptapeptide Boc-Ala1-Leu2-Aib3-Xxx4-Ala5-Leu6-Aib7-OMe which nicely folds into a mixed 310 -/α-helical structure when Xxx= Ala. Analogs of this peptide have been made and studied by replacing central Xxx4 residue with Glycine (α-residue), β-Alanine (β-Αla), γ-aminobutyric acid (Gaba), and ε-aminocaproic acid (ε-Aca). NMR and circular dichroism were used to study the solution structure of these peptides. Crystals of the peptides containing alanine, β-Αla, and Gaba reveal that increasing the number of central methylene (-CH2 -) groups introduces local perturbations even as the helical structure is retained. PMID:26152771

  5. Photo-Induced Inactivation of Viruses: Adsorption of Methylene Blue, Thionine, and Thiopyronine on Qβ Bacteriophage

    NASA Astrophysics Data System (ADS)

    Jockusch, Steffen; Lee, Denis; Turro, Nicholas J.; Leonard, Edward F.

    1996-07-01

    The adsorption of cationic organic dyes (methylene blue, thionine, and thiopyronine) on Qβ bacteriophage was studied by UV-visible and fluorescence spectroscopy. The dyes have shown a strong affinity to the virus and some have been used as sensitizers for photo-induced inactivation of virus. In the methylene blue concentration range of 0.1-5 μ M and at high ratios of dye to virus (greater than 1000 dye molecules per virion), the dyes bind as aggregates on the virus. Aggregation lowers the efficiency of photoinactivation because of self-quenching of the dye. At lower ratios of dye to virus (lower than 500 dye molecules per virion), the dye binds to the virus as a monomer. Fluorescence polarization and time-resolved studies of the fluorescence support the conclusions based on fluorescence quenching. Increasing the ionic strength (adding NaCl) dissociates bound dye aggregates on the virus and releases monomeric dye into the bulk solution.

  6. Modified pineapple peel cellulose hydrogels embedded with sepia ink for effective removal of methylene blue.

    PubMed

    Dai, Hongjie; Huang, Huihua

    2016-09-01

    Novel composite hydrogels based on pineapple peel cellulose and sepia ink were synthesized by homogeneous acetylation of cellulose in ionic liquid 1-butyl-3-methylimidazolium chloride. The structure and morphology of the prepared hydrogels were characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscope, X-ray diffraction, thermogravimetry and differential scanning calorimetry. The effects of acetylation time, acetylation temperature, molar ratio of acetic anhydride/anhydroglucose unit and the additive amount of sepia ink on methylene blue adsorption capacity of the hydrogels embedded with sepia ink were also investigated. Methylene blue adsorption of the hydrogels followed pseudo-second-order kinetic model and sepia ink improved adsorption capacity significantly. The adsorption capacity at equilibrium was increased from 53.72 to 138.25mg/g when the additive amount of sepia ink of the hydrogels was 10%. PMID:27185109

  7. POLLUTION PREVENTION DEMONSTRATION AND EVALUATION OF PAINT APPLICATION EQUIPMENT AND ALTERNATIVES TO METHYLENE CHLORIDE AND METHYL ETHYL KETONE

    EPA Science Inventory

    The report gives results of demonstrations of technologies to prevent or control emissions of hazardous air pollutant (HAPs) and volatile organic compounds (VOCs) from processes with high solvent usage: (1) paint stripping using methylene chloride, (2) cleaning paint equipment wi...

  8. DEVELOPMENTAL TOXICITY OF COPPER CHLORIDE, METHYLENE CHLORIDE,AND 6-AMINONICOTINAMIDE TO EMBRYOS OF THE GRASS SHRIMPPALAEMONETES PUGIO

    EPA Science Inventory

    Embryos of estuarine grass shrimp Palaemonetes pugio have demonstrated sensitivity to various solvents and petroleum products, indicating utility for evaluating estuarine contamination. Testing was performed to establish concentration-response curves for methylene chloride, cop...

  9. Practical methylenation reaction for aldehydes and ketones using new Julia-type reagents.

    PubMed

    Ando, Kaori; Kobayashi, Takahisa; Uchida, Nariaki

    2015-05-15

    A new Julia-type methylenation reagent, 1-methyl-2-(methylsulfonyl)benzimidazole (1e), reacts with a variety of aldehydes and ketones in the presence of either NaHMDS (-55 °C to rt) or t-BuOK (rt, 1 h) in DMF to give the corresponding terminal alkenes in high yields. The byproducts are easily removed, and the reaction conditions are mild and practical.

  10. Reductive alkylation of active methylene compounds with carbonyl derivatives, calcium hydride and a heterogeneous catalyst.

    PubMed

    Guyon, Carole; Duclos, Marie-Christine; Sutter, Marc; Métay, Estelle; Lemaire, Marc

    2015-07-01

    A one-pot two-step reaction (Knoevenagel condensation - reduction of the double bond) has been developed using calcium hydride as a reductant in the presence of a supported noble metal catalyst. The reaction between carbonyl compounds and active methylene compounds such as methylcyanoacetate, 1,3-dimethylbarbituric acid, dimedone and the more challenging dimethylmalonate, affords the corresponding monoalkylated products in moderate to good yields (up to 83%) with minimal reduction of the starting carbonyl compounds. PMID:26053131

  11. Methylenebisnicotiflorin: a rare methylene-bridged bisflavonoid glycoside from ripe Pu-er tea.

    PubMed

    Tao, Mu-Ke; Xu, Min; Zhang, Han; Chen, Hui; Liu, Chang; Zhu, Hong-Tao; Wang, Dong; Yang, Chong-Ren; Zhang, Ying-Jun

    2016-01-01

    A new methylene-bridged dimeric flavonol glycoside, methylenebisnicotiflorin (1), was isolated from ripe Pu-er tea, along with 10 known flavonoids (2-11) and seven known phenolic compounds (12-18). The structure elucidation was based on spectroscopic analysis. Among them, 1,3-dihydroxyphenyl-2-O-sulfate (13), 2,3,4-trihydroxybenzoic acid (16) and 3,3',4,4'-tetrahydroxybiphenyl (18) are reported from tea plants for the first time.

  12. Source reduction for prevention of methylene chloride hazards: cases from four industrial sectors

    PubMed Central

    Roelofs, Cora R; Ellenbecker, Michael J

    2003-01-01

    Background Source reduction, defined as chemical, equipment and process changes that intervene in an industrial process to eliminate or reduce hazards, has not figured as a front-line strategy for the protection of workers' health. Such initiatives are popular for environmental protection, but their feasibility and effectiveness as an industrial hygiene approach have not been well described. Methods We investigated four cases of source reduction as a hazard prevention strategy in Massachusetts companies that had used methylene chloride, an occupational carcinogen, for cleaning and adhesive thinning. Three cases were retrospective and one was prospective, where the researchers assisted with the source reduction process change. Data were collected using qualitative research methods, including in-depth interviews and site visits. Results Motivated by environmental restrictions, a new worker health standard, and opportunity for productivity improvements, three companies eliminated their use of methylene chloride by utilizing available technologies and drop-in substitutes. Aided by technical assistance from the investigators, a fourth case dramatically reduced its use of methylene chloride via process and chemistry changes. While the companies' evaluations of potential work environment impacts of substitutes were not extensive, and in two cases new potential hazards were introduced, the overall impact of the source reduction strategy was deemed beneficial, both from a worker health and a production standpoint. Conclusion The findings from these four cases suggest that source reduction should be considered potentially feasible and effective for reducing or eliminating the potential hazards of methylene chloride exposure. Especially when faced with a hazard that is both an environmental and worker health concern, companies may chose to change their processes rather than rely on local exhaust ventilation equipment or personal protective equipment that might not be as

  13. Adjuvant therapy with methylene blue in the treatment of right ventricular failure after pulmonary embolectomy.

    PubMed

    Raikhelkar, Jayashree K; Milla, Federico; Darrow, Bruce; Scurlock, Corey

    2011-04-01

    Severe pulmonary embolism often leads to right ventricular failure after surgical embolectomy secondary to ischaemia reperfusion injury and acute lung injury (ALI). Acute right ventricular dysfunction is traditionally treated with inotropes and vasopressors to maintain cardiac output and coronary perfusion as well as selective pulmonary vasodilators to provide right ventricular afterload reduction. We report the first case of utilisation of methylene (MB) in a patient with acute right ventricular failure and vasoplegic shock after surgical pulmonary embolectomy. PMID:20952252

  14. Electrochemical preparation of poly(methylene blue)/graphene nanocomposite thin films

    SciTech Connect

    Erçarıkcı, Elif; Dağcı, Kader; Topçu, Ezgi; Alanyalıoğlu, Murat

    2014-07-01

    Highlights: • Poly(MB)/graphene thin films are prepared by a simple electrochemical approach. • Graphene layers in the film show a broad band in visible region of absorbance spectra. • Morphology of composite films indicates both disordered and ordered regions. • XRD reveals that nanocomposite films include rGO layers after electropolymerization process. • Chemically prepared graphene is better than electrochemically prepared graphene for electrooxidation of nitrite. - Abstract: Poly(methylene blue)/graphene nanocomposite thin films were prepared by electropolymerization of methylene blue in the presence of graphene which have been synthesized by two different methods of a chemical oxidation process and an electrochemical approach. Synthesized nanocomposite thin films were characterized by using cyclic voltammetry, UV–vis. absorption spectroscopy, powder X-ray diffraction, and scanning tunneling microscopy techniques. Electrocatalytical properties of prepared poly(methylene blue)/graphene nanocomposite films were compared toward electrochemical oxidation of nitrite. Under optimized conditions, electrocatalytical effect of nanocomposite films of chemically prepared graphene through electrochemical oxidation of nitrite was better than that of electrochemically prepared graphene.

  15. Functional elastic hydrogel as recyclable membrane for the adsorption and degradation of methylene blue.

    PubMed

    Bao, Song; Wu, Dongbei; Wang, Qigang; Su, Teng

    2014-01-01

    Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young's modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g(-1). The hydrogel also exhibited higher separation selectivity to Pb(2+) than Cu(2+). The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables. PMID:24586396

  16. Comparison of acridine orange, methylene blue, and Gram stains for blood cultures.

    PubMed Central

    Mirrett, S; Lauer, B A; Miller, G A; Reller, L B

    1982-01-01

    Direct microscopic screening of blood cultures by Gram stain or methylene blue stain is time consuming and frequently insensitive. Therefore, we evaluated a fluorescent-staining procedure that uses acridine orange (AO) at pH 3.5 and compared it with the methylene blue and Gram stain procedures. All smears were prepared within 24 h of receiving the culture, fixed with methanol, and examined without the results of the companion smears being known. AO-stained smears were examined with incident-light fluorescence at 600 x magnification and confirmed at 1,500x magnification. All bottles macroscopically positive within 24 h were excluded from the study. Of 2,946 cultures entered into the study, 204 (6.9%) were positive within 3 days. The sensitivity and specificity of AO based on these culture results were 52 and 98%, respectively, compared with 38% sensitivity and 99% specificity by methylene blue and Gram stains. The AO staining procedure is a simple, sensitive, screening technique for the early detection of positive blood cultures. PMID:6175656

  17. Adsorption of methylene blue from aqueous solution on pyrolyzed petrified sediment.

    PubMed

    Aroguz, Ayse Z; Gulen, J; Evers, R H

    2008-04-01

    The adsorption kinetics of methylene blue on pyrolyzed petrified sediment (PPS) has been performed using a batch-adsorption technique. The effects of various experimental parameters, such as initial dye concentration, contact time, and temperature were investigated. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. The best correlation coefficient was obtained using the pseudo first-order kinetic model, which shows that the adsorption of methylene blue followed the pseudo-first-order rate expression and the rate constants were evaluated. The Langmuir and Freundlich adsorption isotherm models were applied to describe the equilibrium isotherms and the isotherm constants were determined. It was found that the data fitted well to Langmuir and Freundlich models. The activation energy of adsorption was also evaluated for the adsorption of methylene blue onto pyrolyzed sediment. It was found about 8.5 kJ mol(-1). Thermodynamics parameters DeltaG(o), DeltaH(o), DeltaS(o) were calculated, indicating that this process can be spontaneous and endothermic. The adsorption enthalpy and entropy were found as 14-18.5 kJ mol(-1) and 52.8-67 J mol(-1) K(-1), respectively. The results obtained from the adsorption process using PPS as adsorbent was subjected to student's t-test.

  18. Functional elastic hydrogel as recyclable membrane for the adsorption and degradation of methylene blue.

    PubMed

    Bao, Song; Wu, Dongbei; Wang, Qigang; Su, Teng

    2014-01-01

    Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young's modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g(-1). The hydrogel also exhibited higher separation selectivity to Pb(2+) than Cu(2+). The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables.

  19. Infrared spectroscopy of the methanol cation and its methylene-oxonium isomer

    SciTech Connect

    Mosley, J. D.; Young, J. W.; Duncan, M. A. E-mail: maduncan@uga.edu; Huang, M.; McCoy, A. B. E-mail: maduncan@uga.edu

    2015-03-21

    The carbenium ion with nominal formula [C,H{sub 4},O]{sup +} is produced from methanol or ethylene glycol in a pulsed-discharge supersonic expansion source. The ion is mass selected, and its infrared spectrum is measured from 2000 to 4000 cm{sup −1} using laser photodissociation spectroscopy and the method of rare gas atom tagging. Computational chemistry predicts two isomers, the methanol and methylene-oxonium cations. Predicted vibrational spectra based on scaled harmonic and reduced dimensional treatments are compared to the experimental spectra. The methanol cation is the only isomer produced when methanol is used as a precursor. When ethylene glycol is used as the precursor, methylene-oxonium is produced in addition to the methanol cation. Theoretical results at the CCSD(T)/cc-pVTZ level show that methylene-oxonium is lower in energy than methanol cation by 6.4 kcal/mol, and is in fact the global minimum isomer on the [C,H{sub 4},O]{sup +} potential surface. Methanol cation is trapped behind an isomerization barrier in our source, providing a convenient method to produce and characterize this transient species. Analysis of the spectrum of the methanol cation provides evidence for strong CH stretch vibration/torsion coupling in this molecular ion.

  20. Simultaneous multiselective spectroelectrochemical fiber-optic sensor: demonstration of the concept using methylene blue and ferrocyanide.

    PubMed

    Imai, Kenichiro; Okazaki, Takuya; Hata, Noriko; Taguchi, Shigeru; Sugawara, Kazuharu; Kuramitz, Hideki

    2015-02-17

    Herein, we present a novel spectroelectrochemical fiber-optic sensor that combines electrochemistry, spectroscopy, and electrostatic adsorption in three modes of selectivity. The proposed sensor is simple and consists of a gold mesh cover on a multimode fiber optic that uses attenuated total reflection as the optical detection mode. The sensing is based on changes in the attenuation of the light that passes through the fiber-optic core accompanying the electrochemical oxidation-reduction of an analyte at the electrode. Methylene blue and ferrocyanide were used as model analytes to evaluate the performance of the proposed sensor. The optical transmission changes generated by electrochemical manipulation showed a good linear relationship with the concentration and the limits of detection (3σ) for methylene blue and ferrocyanide at 2.0 × 10(-7) and 1.6 × 10(-3) M, respectively. The sensor responses were successfully enhanced with an additional level of selectivity via an electrostatically adsorbed, self-assembled monolayer (SAM), which consisted of a silane coupling layer, a polyanion, and a polycation. The improvement observed in the sensitivity of a SAM-modified fiber-optic sensor was rather encouraging. The optimized sensor had detection limits (3σ) of 8.3 × 10(-9) M for methylene blue and 7.1 × 10(-4) M for ferrocyanide. The developed sensor was successfully applied to the detection of ferrocyanide in simulated nuclear waste.

  1. Determination of low level sulfides in environmental waters by automated gas dialysis/methylene blue colorimetry

    SciTech Connect

    Francom, D. Goodwin, L.R.; Dieken, F.P. )

    1990-01-01

    A sensitive and rapid automated method has been developed for the selective analysis of acid extractable sulfide in environmental samples by combining gas dialysis separation techniques with methylene blue detection procedures. Acid extractable sulfide is separated from the sample matrix by the gas dialysis membrane and subsequently trapped in a dilute sodium hydroxide receiving stream. This stream is reacted with N,N-dimethyl-p-phenylenediamine and ferric chloride to produce methylene blue which is then quantitated colorimetrically at 660 nm. For standards and nonturbid environmental samples, there is good agreement between the results obtained by this procedure and the standard methylene blue method. The effect of interferences on the accurate determination of sulfide by both methods was also examined and it was found that cupric ions significantly interfered with sulfide estimation. To obtain adequate sulfide recoveries in tap water and environmental samples ascorbic acid must be added as an antioxidant. A detection limit of 2 {mu}g/L of sulfide has been obtained using this procedure.

  2. Impact of methylene blue in addition to norepinephrine on the intestinal microcirculation in experimental septic shock.

    PubMed

    Nantais, Jordan; Dumbarton, Tristan C; Farah, Nizam; Maxan, Alexander; Zhou, Juan; Minor, Samuel; Lehmann, Christian

    2014-01-01

    Methylene blue (MB) has been used with some success as a treatment for the vasoplegia of vasopressor-refractory septic shock. The putative mechanism of action of MB is the inhibition of endothelial nitric oxide within the microvasculature and improved responsiveness to endogenous catecholamines (norepinephrine (NE)). However, to date, no study has demonstrated the microcirculatory effect of methylene blue in septic shock. The objective of this randomized, controlled, animal study was to show, in an experimentally-induced, septic shock model in rats, the effects of MB and NE on global hemodynamics and the microcirculation. Mean arterial pressure (MAP) was drastically reduced following bacterial endotoxin (lipopolysaccharide, LPS) administration in animals not receiving vasopressors. Only the combination of NE + MB restored MAP to control levels by the end of the three hour experiment. Intravital microscopy of the microcirculation was performed in the terminal ileum in order to examine functional capillary density in intestinal muscle layers and the mucosa, as well as leukocyte activation in venules (rolling, adhesion to the endothelium). Untreated LPS animals showed a significant increase in leukocyte adhesion and a decrease in capillary perfusion in the intestinal microcirculation. In groups receiving NE or NE+MB, we observed a significant decrease in leukocyte adhesion and improved functional capillary density, indicating that microvasculature function was improved. This study suggests that methylene blue may be able to improve hemodynamics while preserving microvascular function in septic shock.

  3. Methylene Blue: The Long and Winding Road from Stain to Brain: Part 1.

    PubMed

    Howland, Robert H

    2016-09-01

    Methylene blue, first discovered and used as a dye in the textile industry, has long been used for biological staining in histology, bacteriology, and hematology. Because of its unique physiochemical properties, it was the first synthetic drug used in medicine, having been used to treat malaria more than one century ago. Methylene blue was also one of the first drugs used for the treatment of patients with psychosis at the end of the 19th century and was the lead drug in the serendipitous development of phenothiazine antipsychotic drugs in the mid-20th century. It was studied in bipolar disorder in the 1980s and has been investigated in neurodegenerative disorders in recent years. The history of methylene blue from its discovery as a dye to its use as a stain and then its therapeutic application in medicine is an example of how a drug's use can evolve over time through careful observation, clinical needs, serendipity, and the integration of concepts from different disciplines. [Journal of Psychosocial Nursing and Mental Health Services, 54(9), 21-24.]. PMID:27576224

  4. Mutations induced by methylene blue plus light in single-stranded M13mp2.

    PubMed Central

    McBride, T J; Schneider, J E; Floyd, R A; Loeb, L A

    1992-01-01

    Reactive oxygen species are generated by a variety of cellular processes. These endogenously generated, reactive intermediates produce a multiplicity of DNA alterations and mutations and have been implicated in the pathogenesis of several human diseases. We report here that treatment of single-stranded M13mp2 bacteriophage DNA with methylene blue and white light generates increased levels of 8-hydroxydeoxyguanosine and that mutagenesis is both highly specific and dependent on the SOS response. Lesions produced block the progression of DNA synthesis one base preceding template guanines. In SOS-induced Escherichia coli, 97% of all methylene blue-induced mutations in the lacZ alpha gene of M13mp2 DNA are single-base substitutions opposite template guanines. The most frequent mutations are G----C transversions. The G----T transversions expected from the presence of 8-hydroxydeoxyguanosine in the template strand occur, but at a lower frequency. Sequence data together with SOS dependency and the presence of replication blockage demonstrate that while 8-hydroxydeoxyguanosine may serve as an important marker to monitor oxygen-induced DNA damage in humans, it does not account for either the observed blockage to replication or the mutagenesis by methylene blue plus light in SOS-induced E. coli. Instead, an as yet unidentified lesion generated by active oxygen species is a more potent mutagenic event. Images PMID:1495976

  5. Methylene blue- and thiol-based oxygen depletion for super-resolution imaging.

    PubMed

    Schäfer, Philip; van de Linde, Sebastian; Lehmann, Julian; Sauer, Markus; Doose, Sören

    2013-03-19

    Anaerobic conditions are often required in solution-based bionanotechnological applications. Efficient oxygen depletion is essential for increasing photostability, optimizing fluorescence signals, and adjusting kinetics of fluorescence intermittency in single-molecule fluorescence spectroscopy/microscopy, particularly for super-resolution imaging techniques. We characterized methylene blue (MB)- and thiol-based redox reactions with the aim of designing an oxygen scavenger system as an alternative to the established enzyme-based oxygen scavenging systems or purging procedures. Redox reactions of the chromophore methylene blue in aqueous solution, commonly visualized in the blue bottle experiment, deplete molecular oxygen as long as a sacrificial reduction component is present in excess concentrations. We demonstrate that methylene blue in combination with reducing compounds such as β-mercaptoethylamine (MEA) can serve as fast and efficient oxygen scavenger. Efficient oxygen scavenging in aqueous solution is also possible with mere β-mercaptoethylamine at mM concentrations. We present kinetic parameters of the relevant reactions, pH-stability of the MB/MEA-oxygen scavenging system, and its application in single-molecule based super-resolution imaging.

  6. The kinetics of electron transfer reaction of methylene green and titanium trichloride in different solvents

    NASA Astrophysics Data System (ADS)

    Saeed, Rehana; Nadeem, Syed Muhammad Saqib

    2016-06-01

    The kinetics of the electron transfer reaction of methylene green and titanium trichloride was investigated in different solvents by spectrophotometry at different temperatures. The the reaction rate was determined by monitoring the absorbance as a function of time at λmax 655 nm. The reaction is pseudo-first order, dependent only on the concentration of titanium trichloride at a fixed concentration of methylene green. The effect of an aqueous alcoholic solvent was studied in the acidic range of pH from 4 to 7. It was observed that the reaction rate increased with an increase in polarity of the reaction medium. The the reaction rate was high in acidic conditions and decreased with a further increase in acidity. The increase in temperature increased the rate of the electron transfer reaction of methylene green and titanium trichloride. The activation energy ( E a) was calculated by the Arrhenius relation. The absence of any reaction intermediate was confirmed by spectroscopic and kinetic investigations. A plausible mechanism for the reaction in line with outer-sphere reaction pathway has been proposed. Thermodynamic parameters such as the activation energy ( E a), enthalpy change (Δ H), free energy change (Δ G), and entropy change (Δ S) were also evaluated

  7. Functional Elastic Hydrogel as Recyclable Membrane for the Adsorption and Degradation of Methylene Blue

    PubMed Central

    Bao, Song; Wu, Dongbei; Wang, Qigang; Su, Teng

    2014-01-01

    Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young’s modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g−1. The hydrogel also exhibited higher separation selectivity to Pb2+ than Cu2+. The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables. PMID:24586396

  8. Supramolecular arrangement of 3,5-bis[methylene(dihydroxyphosphoryl)]benzoic acid and its complex with calcium

    NASA Astrophysics Data System (ADS)

    Przybył, Bartosz; Zoń, Jerzy; Janczak, Jan

    2013-09-01

    3,5-Bis[methylene(dihydroxyphosphoryl)]benzoic acid and its complex with calcium in the crystalline form were obtained. The 3,5-bis[methylene(dihydroxyphosphoryl)]benzoic acid crystallises as acetone monosolvate (1a) while its calcium complex as methanol disolvate (1b). The solvent molecules in the crystals are disordered. The 3,5-bis[methylene(dihydroxy-phosphoryl)]benzoic acid molecules in crystal 1a are interconnected via OH⋯O hydrogen bonds forming two-dimensional layers parallel to (1 0 0) plane. Within the layers there are present holes that occupied disordered acetone molecules. In 1b the calcium cation is surrounded by six singly deprotonated 3,5-bis[methylene(dihydroxyphosphoryl)]benzoic acid forming distorted octahedral environment. Each singly deprotonated 3,5-bis[methylene(dihydroxyphosphoryl)]benzoic acid links three calcium cations forming two-dimensional coordinating polymers parallel to (0 1 0) plane. The OH···O hydrogen bonds between the singly deprotonated 3,5-bis[methylene(dihydroxyphosphoryl)]benzoic acid ligands stabilize the two-dimensional polymers. Statistically disordered methanol molecules are located in the holes between the two-dimensional coordinating polymers and interact with them via OH···O hydrogen bonds.

  9. Methylene Blue-Loaded Dissolving Microneedles: Potential Use in Photodynamic Antimicrobial Chemotherapy of Infected Wounds

    PubMed Central

    Caffarel-Salvador, Ester; Kearney, Mary-Carmel; Mairs, Rachel; Gallo, Luigi; Stewart, Sarah A.; Brady, Aaron J.; Donnelly, Ryan F.

    2015-01-01

    Photodynamic therapy involves delivery of a photosensitising drug that is activated by light of a specific wavelength, resulting in generation of highly reactive radicals. This activated species can cause destruction of targeted cells. Application of this process for treatment of microbial infections has been termed “photodynamic antimicrobial chemotherapy” (PACT). In the treatment of chronic wounds, the delivery of photosensitising agents is often impeded by the presence of a thick hyperkeratotic/necrotic tissue layer, reducing their therapeutic efficacy. Microneedles (MNs) are an emerging drug delivery technology that have been demonstrated to successfully penetrate the outer layers of the skin, whilst minimising damage to skin barrier function. Delivering photosensitising drugs using this platform has been demonstrated to have several advantages over conventional photodynamic therapy, such as, painless application, reduced erythema, enhanced cosmetic results and improved intradermal delivery. The aim of this study was to physically characterise dissolving MNs loaded with the photosensitising agent, methylene blue and assess their photodynamic antimicrobial activity. Dissolving MNs were fabricated from aqueous blends of Gantrez® AN-139 co-polymer containing varying loadings of methylene blue. A height reduction of 29.8% was observed for MNs prepared from blends containing 0.5% w/w methylene blue following application of a total force of 70.56 N/array. A previously validated insertion test was used to assess the effect of drug loading on MN insertion into a wound model. Staphylococcus aureus, Escherichia coli and Candida albicans biofilms were incubated with various methylene blue concentrations within the range delivered by MNs in vitro (0.1–2.5 mg/mL) and either irradiated at 635 nm using a Paterson Lamp or subjected to a dark period. Microbial susceptibility to PACT was determined by assessing the total viable count. Kill rates of >96%, were achieved for

  10. Methylene Blue-Loaded Dissolving Microneedles: Potential Use in Photodynamic Antimicrobial Chemotherapy of Infected Wounds.

    PubMed

    Caffarel-Salvador, Ester; Kearney, Mary-Carmel; Mairs, Rachel; Gallo, Luigi; Stewart, Sarah A; Brady, Aaron J; Donnelly, Ryan F

    2015-01-01

    Photodynamic therapy involves delivery of a photosensitising drug that is activated by light of a specific wavelength, resulting in generation of highly reactive radicals. This activated species can cause destruction of targeted cells. Application of this process for treatment of microbial infections has been termed "photodynamic antimicrobial chemotherapy" (PACT). In the treatment of chronic wounds, the delivery of photosensitising agents is often impeded by the presence of a thick hyperkeratotic/necrotic tissue layer, reducing their therapeutic efficacy. Microneedles (MNs) are an emerging drug delivery technology that have been demonstrated to successfully penetrate the outer layers of the skin, whilst minimising damage to skin barrier function. Delivering photosensitising drugs using this platform has been demonstrated to have several advantages over conventional photodynamic therapy, such as, painless application, reduced erythema, enhanced cosmetic results and improved intradermal delivery. The aim of this study was to physically characterise dissolving MNs loaded with the photosensitising agent, methylene blue and assess their photodynamic antimicrobial activity. Dissolving MNs were fabricated from aqueous blends of Gantrez(®) AN-139 co-polymer containing varying loadings of methylene blue. A height reduction of 29.8% was observed for MNs prepared from blends containing 0.5% w/w methylene blue following application of a total force of 70.56 N/array. A previously validated insertion test was used to assess the effect of drug loading on MN insertion into a wound model. Staphylococcus aureus, Escherichia coli and Candida albicans biofilms were incubated with various methylene blue concentrations within the range delivered by MNs in vitro (0.1-2.5 mg/mL) and either irradiated at 635 nm using a Paterson Lamp or subjected to a dark period. Microbial susceptibility to PACT was determined by assessing the total viable count. Kill rates of >96%, were achieved for S

  11. A dose-finding study of methylene blue to inhibit nitric oxide actions in the hemodynamics of human septic shock.

    PubMed

    Juffermans, Nicole P; Vervloet, Marc G; Daemen-Gubbels, Catharina R G; Binnekade, Jan M; de Jong, Martin; Groeneveld, A B Johan

    2010-05-15

    Methylene blue increases blood pressure and myocardial function in septic shock mainly by inhibiting nitric oxide (NO) actions. However, a dose-dependency of methylene blue has not been established. Therefore, the compound is currently used as rescue treatment only. To evaluate dose-dependency, a prospective, randomized, double blind, single centre study was performed in 15 consecutive, mechanically ventilated patients with septic shock admitted to the intensive care unit, in whom methylene blue was infused at 1 mg/kg (n=4), 3 mg/kg (n=6) or 7 mg/kg (n=5) over 20 min. Hemodynamic parameters were measured before and after the infusion. Gastric tonometry was performed. Methylene blue treatment increased heart rate, cardiac index, mean arterial, pulmonary artery, pulmonary artery occlusion and central venous pressures, systemic vascular resistance, ventricular stroke work indices and O(2) delivery and uptake, and decreased lactate levels. Methylene blue had a dose-dependent effect on cardiac index, mean arterial, mean pulmonary artery and pulmonary artery occlusion pressures, left ventricular function, O(2) delivery and consumption and lactate levels. The drug dose-dependently increased the gastric-arterial blood PCO(2) gap. The data suggest that in human septic shock, methylene blue increases mean arterial blood pressure by an increase in cardiac index and systemic vascular resistance. The rise in cardiac index is caused by an increase in left ventricular filling and function, increasing tissue oxygenation, even at a dose of 1mg/kg. High doses of methylene blue may compromise splanchnic perfusion, even though further enhancing global hemodynamics, and should therefore, be avoided in future studies.

  12. 40 CFR 721.8485 - 2-Propenoic acid, 2-methyl-, (octahydro-4,7-methano-1H- indene-5-diyl)bis(methylene) ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-, (octahydro-4,7-methano-1H- indene-5-diyl)bis(methylene) ester. 721.8485 Section 721.8485 Protection of...-methyl-, (octahydro-4,7-methano-1H- indene-5-diyl)bis(methylene) ester. (a) Chemical substance and...-, (octahydro-4,7-methano- 1H- indene-5-diyl)bis(methylene) ester (PMN P-99-1075; CAS No. 43048-08-4) is...

  13. 40 CFR 721.8485 - 2-Propenoic acid, 2-methyl-, (octahydro-4,7-methano-1H- indene-5-diyl)bis(methylene) ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-, (octahydro-4,7-methano-1H- indene-5-diyl)bis(methylene) ester. 721.8485 Section 721.8485 Protection of...-methyl-, (octahydro-4,7-methano-1H- indene-5-diyl)bis(methylene) ester. (a) Chemical substance and...-, (octahydro-4,7-methano- 1H- indene-5-diyl)bis(methylene) ester (PMN P-99-1075; CAS No. 43048-08-4) is...

  14. Novel alkylimidazolium/vanadium pentoxide intercalation compounds with excellent adsorption performance for methylene blue

    SciTech Connect

    Kong Aiguo; Ding Yongjie; Wang Ping; Zhang Hengqiang; Yang Fan; Shan Yongkui

    2011-02-15

    Novel alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds were synthesized by a redox reaction between iodide ion and V{sub 2}O{sub 5}. The X-ray photoelectron spectroscopy and the diffuse reflectance UV-vis spectrometry experiments reveal that the vanadium in the intercalated V{sub 2}O{sub 5} products was partially reduced by an iodide ion and the resultant iodine can be removed in the final products. The transmission electron microscope observation and X-ray diffraction analysis testify that the prepared alkylimidazolium/V{sub 2}O{sub 5} intercalation compounds have typical lamellar structure with different d{sub 100} interlayer spacing values and the special straw-like nanofiber morphology with the length of 0.5-10 {mu}m. Systematic investigation indicates that new intercalation compounds possess the extraordinary adsorption performance for methylene blue in an aqueous solution. -- Graphical abstract: The alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds with special straw-like nanofiber morphology were synthesized by a redox reaction between iodide ion and V{sub 2}O{sub 5}, which show the excellent adsorption performance for methylene blue in an aqueous medium. Display Omitted Research highlights: {yields} Novel alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds. {yields} A simple preparation method by a redox reaction between iodide ion in ionic liquid and V{sub 2}O{sub 5}. {yields} The excellent adsorption performance for methylene blue in an aqueous medium.

  15. ANALYSIS OF VAPORS FROM METHYLENE CHLORIDE EXTRACTS OF NUCLEAR GRADE HEPA FILTER FIBERGLASS SAMPLES

    SciTech Connect

    FRYE JM; ANASTOS HL; GUTIERREZ FC

    2012-06-07

    While several organic compounds were detected in the vapor samples used in the reenactment of the preparation of mounts from the extracts of nuclear grade high-efficiency particulate air filter fiberglass samples, the most significant species present in the samples were methylene chloride, phenol, phenol-d6, and 2-fluorophenol. These species were all known to be present in the extracts, but were expected to have evaporated during the preparation of the mounts, as the mounts appeared to be dry before any vapor was collected. These species were present at the following percentages of their respective occupational exposure limits: methylene chloride, 2%; phenol, 0.4%; and phenol-d6, 0.6%. However, there is no established limit for 2-fluorophenol. Several other compounds were detected at low levels for which, as in the case of 2-fluorophenol, there are no established permissible exposure limits. These compounds include 2-chlorophenol; N-nitroso-1-propanamine; 2-fluoro-1,1{prime}-biphenyl; 1,2-dihydroacenaphthylene; 2,5-cyclohexadiene-1,4-dione,2,6-bis(1,1-dimethylethyl); trimethyl oxirane; n-propylpropanamine; 2-(Propylamino)ethanol; 4-methoxy-1-butene; 6-methyl-5-hepten-2-one; and 3,4-dimethylpyridine. Some of these were among those added as surrogates or spike standards as part ofthe Advanced Technologies and Laboratories International, Inc. preparation ofthe extract of the HEPA filter media and are indicated as such in the data tables in Section 2, Results; other compounds found were not previously known to be present. The main inorganic species detected (sulfate, sodium, and sulfur) are also consistent with species added in the preparation of the methylene chloride extract of the high-efficiency particulate air sample.

  16. Silver-Catalyzed Cross-Coupling of Isocyanides and Active Methylene Compounds by a Radical Process.

    PubMed

    Liu, Jianquan; Liu, Zhenhua; Liao, Peiqiu; Zhang, Lin; Tu, Tao; Bi, Xihe

    2015-09-01

    Isocyanides are versatile building blocks, and have been extensively exploited in C-H functionalization reactions. However, transition-metal-catalyzed direct C-H functionalization reactions with isocyanides suffer from over-insertion of isocyanides. Reported herein is a radical coupling/isomerization strategy for the cross-coupling of isocyanides with active methylene compounds through silver-catalysis. The method solves the over-insertion issue and affords a variety of otherwise difficult to synthesize β-aminoenones and tricarbonylmethanes under base- and ligand-free conditions. This report presents a new fundamental C-C bond-forming reaction of two basic chemicals.

  17. Congenital Methemoglobinemia Type II-Clinical Improvement with Short-Term Methylene Blue Treatment.

    PubMed

    Cooper, Monica S; Randall, Melinda; Rowell, Margaret; Charlton, Margaret; Greenway, Anthea; Barnes, Chris

    2016-03-01

    We report a case of prophylactic management with methylene blue (MB) in an almost 4-year-old male with congenital methemoglobinemia type II. He has a CYB5R3 compound heterozygote mutation, causing a cytochrome-b(5) reductase deficiency. Since the MB treatment regimen has commenced, his methemoglobin level has been significantly lower. He has shown modest behavioral improvements (as assessed on the Achenbach behavior report scales). There have been no iatrogenic side effects. These findings are encouraging for symptomatic improvement with regular prophylactic MB treatment but represent a single case report, which must be interpreted with caution.

  18. Mechanism of complexation of the phenothiazine dye methylene blue with fullerene C60

    NASA Astrophysics Data System (ADS)

    Buchelnikov, A. S.; Kostyukov, V. V.; Yevstigneev, M. P.; Prylutskyy, Yu. I.

    2013-04-01

    The complexation of fullerene C60 with the aromatic dye methylene blue (MB) in aqueous solution was studied. Spectrophotometric titration revealed a reasonably strong interaction between C60 and MB molecules with an equilibrium constant K = 2110 L/mol and the binding of up to five dye molecules with the surface of C60. The energy analysis of the MB-C60 system showed that the intermolecular and hydrophobic interactions were dominant in the energy profile of the complexation, and while the electrostatic factor played an insignificant role.

  19. Adsorption of methylene blue dye from aqueous solutions using Eichhornia crassipes.

    PubMed

    Wanyonyi, Wycliffe Chisutia; Onyari, John Mmari; Shiundu, Paul Mwanza

    2013-09-01

    Adsorption of methylene blue (MB) from aqueous solution using dried roots, stems, and leaves of Eichhornia crassipes biomass obtained from Lake Victoria was studied. Batch experimental results revealed that the adsorption process was highly dependent on adsorbent dosage, initial MB concentration, E. crassipes particle size and aqueous solution temperature. The isotherm data fitted Freundlich mathematical models with maximum dye adsorption of 35.37 mg g(-1). Roots adsorbed over 99 % of the MB in <5 min. Sorption kinetics followed a pseudo-second-order model. Results provide evidence that E. crassipes is an effective and inexpensive biomaterial for dye removal from aqueous dye solutions and industrial effluents.

  20. Methylene blue sensitized gelatin as a photosensitive medium for conventional and polarizing holography.

    PubMed

    Solano, C; Lessard, R A; Roberge, P C

    1987-05-15

    The properties of thin gelatin films sensitized with a dye (methylene blue) when used as a holographic material are discussed. On illumination the excited dye molecule changes its structure giving a colorless molecule. The higher rate of bleaching and therefore the higher diffraction efficiency of the developed phase gratings are obtained in an oxygen-free atmosphere. Furthermore, the light absorption probability of the dye molecules depends on its position with respect to the electric vector of the light, with the result that the exposed part of the dye becomes dichroic when illuminated with linearly polarized light. This result allows the use of this material for polarizing holography. PMID:20454433

  1. Encapsulation of methylene blue in polyacrylamide nanoparticle platforms protects its photodynamic effectiveness.

    PubMed

    Tang, Wei; Xu, Hao; Park, Edwin J; Philbert, Martin A; Kopelman, Raoul

    2008-05-01

    The ability to prevent methylene blue (MB), a photosensitizer, from being reduced by plasma reductases will greatly improve its efficacy in photodynamic therapy (PDT) applications. We have developed a delivery approach for PDT by encapsulating MB using nanoparticle platforms (NPs). The 30-nm polyacrylamide-based NPs provide protection for the embedded MB against reduction by diaphorase enzymes. Furthermore, our data shows the matrix-protected MB efficiently induces photodynamic damage to tumor cells. The unprecedented results demonstrate the significant in vitro photodynamic effectiveness of MB when encapsulated within NPs, which promises to open new opportunities for MB in its in vivo and clinical studies.

  2. Methylene Blue Dichromated-Gelatin Holograms: Antihumidity Method for Taking Off Strongly Adsorbing Humidity Groups

    NASA Astrophysics Data System (ADS)

    Wang, Ketai; Guo, Lurong; Zhu, Jianhua; Zhang, Weiping; Cheng, Bo

    1998-01-01

    A new, to our knowledge, method of modifying methylene blue dichromated-gelatin (MBDCG) holograms by use of ninhydrin and removal of their amino groups and carboxyl groups, which strongly adsorb humidity, has been developed. The modified MBDCG holograms are stable for 1000-line /mm gratings (diffractional efficiency of 95%) in a high-humidity environment (relative humidity of 80% -85%). The modifying reaction does not affect the diffraction efficiency of the MBDCG holograms. It is demonstrated that the amino groups and carboxyl groups of the side chains in the gelatin do not undergo the chelation reaction with Cr iii in the sensitive area.

  3. Congenital Methemoglobinemia Type II-Clinical Improvement with Short-Term Methylene Blue Treatment.

    PubMed

    Cooper, Monica S; Randall, Melinda; Rowell, Margaret; Charlton, Margaret; Greenway, Anthea; Barnes, Chris

    2016-03-01

    We report a case of prophylactic management with methylene blue (MB) in an almost 4-year-old male with congenital methemoglobinemia type II. He has a CYB5R3 compound heterozygote mutation, causing a cytochrome-b(5) reductase deficiency. Since the MB treatment regimen has commenced, his methemoglobin level has been significantly lower. He has shown modest behavioral improvements (as assessed on the Achenbach behavior report scales). There have been no iatrogenic side effects. These findings are encouraging for symptomatic improvement with regular prophylactic MB treatment but represent a single case report, which must be interpreted with caution. PMID:26574897

  4. Chloroacetate-promoted selective oxidation of heterobenzylic methylenes under copper catalysis.

    PubMed

    Liu, Jianming; Zhang, Xin; Yi, Hong; Liu, Chao; Liu, Ren; Zhang, Heng; Zhuo, Kelei; Lei, Aiwen

    2015-01-19

    The efficient selective oxidation and functionalization of C-H bonds with molecular oxygen and a copper catalyst to prepare the corresponding ketones was achieved with ethyl chloroacetate as a promoter. In this transformation, various substituted N-heterocyclic compounds were well tolerated. Preliminary mechanistic investigations indicated that organic radical species were involved in the overall process. The N-heterocyclic compounds and ethyl chloroacetate work synergistically to activate C-H bonds in the methylene group, which results in the easy generation of free radical intermediates, thus leading to the corresponding ketones in good yields. PMID:25483218

  5. Encapsulation of methylene blue in polyacrylamide nanoparticle platforms protects its photodynamic effectiveness.

    PubMed

    Tang, Wei; Xu, Hao; Park, Edwin J; Philbert, Martin A; Kopelman, Raoul

    2008-05-01

    The ability to prevent methylene blue (MB), a photosensitizer, from being reduced by plasma reductases will greatly improve its efficacy in photodynamic therapy (PDT) applications. We have developed a delivery approach for PDT by encapsulating MB using nanoparticle platforms (NPs). The 30-nm polyacrylamide-based NPs provide protection for the embedded MB against reduction by diaphorase enzymes. Furthermore, our data shows the matrix-protected MB efficiently induces photodynamic damage to tumor cells. The unprecedented results demonstrate the significant in vitro photodynamic effectiveness of MB when encapsulated within NPs, which promises to open new opportunities for MB in its in vivo and clinical studies. PMID:18298950

  6. Spectroscopic studies of the interactive model of methylene blue with DNA by means of β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Zhao, Guang-Chao; Zhu, Jun-Jie; Chen, Hong-Yuan

    1999-05-01

    The formation of the inclusion complex of methylene blue with β-cyclodextrin is studied by spectroscopic and electrochemical methods and the binding constant of the inclusion complex is 4.5×10 3 l mol -1. The interactive model of methylene blue with DNA has been investigated by means of the inclusion action of β-cyclodextrin. Through the changes of absorption and fluorescence spectra, the intrinsic binding constant ( k) of methylene blue with DNA and inclusion complex with DNA is obtained. In the case of 20 m mol l -1 Tris buffer solution (pH 7.2), their values are 1.53×10 5 l mol -1 and 9.98×10 4 l mol -1, respectively. The experimental results suggest that the inclusion complex does not decompose when it interacts with DNA. The binding number ( n) is 1 for both methylene blue and inclusion complex with DNA. According to the experimental results, it can be inferred that the interactive model of methylene blue with DNA is 'electrostatic binding'. This conclusion is able to explain the experimental phenomena clearly.

  7. Gold nanoparticles enhance methylene blue–induced photodynamic therapy: a novel therapeutic approach to inhibit Candida albicans biofilm

    PubMed Central

    Khan, Shakir; Alam, Fahad; Azam, Ameer; Khan, Asad U

    2012-01-01

    This article explores the novel gold nanoparticle–enhanced photodynamic therapy of methylene blue against recalcitrant pathogenic Candida albicans biofilm. Physiochemical (X-ray diffraction, ultraviolet-visible absorption, photon cross-correlation, FTIR, and fluorescence spectroscopy) and electron microscopy techniques were used to characterize gold nanoparticles as well as gold nanoparticle–methylene blue conjugate. A 38.2-J/cm2 energy density of 660-nm diode laser was applied for activation of gold nanoparticle–methylene blue conjugate and methylene blue against C. albicans biofilm and cells. Antibiofilm assays, confocal laser scanning, and electron microscopy were used to investigate the effects of the conjugate. Physical characteristics of the gold nanoparticles (21 ± 2.5 nm and 0.2 mg/mL) and methylene blue (20 μg/mL) conjugation were confirmed by physicochemical and electron microscopy techniques. Antibiofilm assays and microscopic studies showed significant reduction of biofilm and adverse effect against Candida cells in the presence of conjugate. Fluorescence spectroscopic study confirmed type I photo toxicity against biofilm. Gold nanoparticle conjugate–mediated photodynamic therapy may be used against nosocomially acquired refractory Candida albicans biofilm. PMID:22802686

  8. In Situ XANES Study of CuO/TiO2 Thin Films During Photodegradation of Methylene Blue

    NASA Astrophysics Data System (ADS)

    Hsiung, Tung Li; Wang, H. Paul; Wei, Yu-Ling

    2007-02-01

    Speciation of copper in the CuO/TiO2 thin film (synthesized by the doctor-blade deposition method) during photocatalytic decomposition of methylene blue has been studied by in situ X-ray absorption near-edge structural (XANES) spectroscopy. During the UV/VIS radiation (90 min), in the presence of methylene blue, a decrease of Cu(II) and an increases of Cu(0) and Cu(I) fractions in the CuO/TiO2 thin film are observed by in situ XANES. The r-space Fourier transformation EXAFS (extend X-ray absorption fine structural) spectra also show that the bond distance of Cu-O in the thin film is decreased by 0.03 Å during photocatalytic degradation of methylene blue.

  9. In Situ XANES Study of CuO/TiO2 Thin Films During Photodegradation of Methylene Blue

    SciTech Connect

    Hsiung Tungli; Wang, H. Paul; Wei Yuling

    2007-02-02

    Speciation of copper in the CuO/TiO2 thin film (synthesized by the doctor-blade deposition method) during photocatalytic decomposition of methylene blue has been studied by in situ X-ray absorption near-edge structural (XANES) spectroscopy. During the UV/VIS radiation (90 min), in the presence of methylene blue, a decrease of Cu(II) and an increases of Cu(0) and Cu(I) fractions in the CuO/TiO2 thin film are observed by in situ XANES. The r-space Fourier transformation EXAFS (extend X-ray absorption fine structural) spectra also show that the bond distance of Cu-O in the thin film is decreased by 0.03 A during photocatalytic degradation of methylene blue.

  10. Methylene blue microbubbles as a model dual-modality contrast agent for ultrasound and activatable photoacoustic imaging.

    PubMed

    Jeon, Mansik; Song, Wentao; Huynh, Elizabeth; Kim, Jungho; Kim, Jeesu; Helfield, Brandon L; Leung, Ben Y C; Goertz, David E; Zheng, Gang; Oh, Jungtaek; Lovell, Jonathan F; Kim, Chulhong

    2014-01-01

    Ultrasound and photoacoustic imaging are highly complementary modalities since both use ultrasonic detection for operation. Increasingly, photoacoustic and ultrasound have been integrated in terms of hardware instrumentation. To generate a broadly accessible dual-modality contrast agent, we generated microbubbles (a standard ultrasound contrast agent) in a solution of methylene blue (a standard photoacoustic dye). This MB2 solution was formed effectively and was optimized as a dual-modality contrast solution. As microbubble concentration increased (with methylene blue concentration constant), photoacoustic signal was attenuated in the MB2 solution. When methylene blue concentration increased (with microbubble concentration held constant), no ultrasonic interference was observed. Using an MB2 solution that strongly attenuated all photoacoustic signal, high powered ultrasound could be used to burst the microbubbles and dramatically enhance photoacoustic contrast (>800-fold increase), providing a new method for spatiotemporal control of photoacoustic signal generation.

  11. Modified use of methylene blue in the tissue compression technique to detect sarcocysts in meat-producing animals.

    PubMed

    Ng, Yit Han; Subramaniam, Vellayan; Lau, Yee Ling

    2015-11-30

    Sarcocystosis in meat-producing animals is a major cause of reduced productivity in many countries, especially those that rely on agriculture. Although several diagnostic methods are available to detect sarcocystosis, many are too time-consuming for routine use in abattoirs and meat inspection centers, where large numbers of samples need to be tested. This study aimed to compare the sensitivity of the methylene blue tissue preparation, unstained tissue preparation and nested PCR in the detection of sarcocysts in tissue samples. Approximately three-fold more sarcocysts were detected in methylene blue-stained tissue compared to unstained controls (McNemar's test: P<0.01). Test sensitivity was comparable to that of the gold standard for sarcocyst detection, nested polymerase chain reaction. These results suggest that methylene blue can be used in tissue compression as a rapid, safe, and inexpensive technique for the detection of ruminant sarcocystosis in abattoirs. PMID:26455572

  12. Enhanced photocatalytic degradation of methylene blue by metal-modified silicon nanowires

    SciTech Connect

    Brahiti, N.; Hadjersi, T.; Menari, H.; Amirouche, S.; El Kechai, O.

    2015-02-15

    Highlights: • SiNWs modified with Pd, Au and Pt were used as photocatalysts to degrade MB. • Yield of photodegardation increases with UV irradiation time. • SiNWs modified with Pd nanoparticles show the best photocatalytic activity. • A degradation of 97% was obtained after 200 min of UV irradiation. - Abstract: Silicon nanowires (SiNWs) modified with Au, Pt and Pd nanoparticles were used as heterogeneous photocatalysts for the photodegradation of methylene blue in water under UV light irradiation. The modification of SiNWs was carried out by deposition of metal nanoparticles using the electroless metal deposition (EMD) technique. The effect of metal nanoparticles deposition time on the photocatalytic activity was studied. It was found that the photocatalytic activity of modified SiNWs was enhanced when the deposition time of metal nanoparticles was increased. In addition of modified SiNWs with Pt, Au and Pd nanoparticles, oxidized silicon substrate (Ox-Si), oxidized silicon nanowires (Ox-SiNWs) and hydrogen-terminated silicon nanowires (H-SiNWs) were also evaluated for the photodegradation of methylene blue.

  13. Effect of methylene blue-mediated photodynamic therapy for treatment of basal cell carcinoma.

    PubMed

    Samy, Nevien A; Salah, Manal M; Ali, Maha F; Sadek, Ahmed M

    2015-01-01

    Photodynamic therapy (PDT) is regarded as a treatment option for basal cell carcinoma (BCC). The aim of this study is to investigate the efficacy of methylene blue (MB)-based PDT in patients suffering from nodular or ulcerative BCCs. This study is a prospective clinical trial with a 6-months follow-up. The study setting is at the Dermatology Clinic at NILES, Cairo University, Egypt. Seventeen patients complaining of nodular BCC (nBCC) and three patients complaining of ulcerative BCC (uBCC) were taken as samples. Methylene blue, the photosensitizer, was prepared in two different formulas: liposomal-loaded MB (LMB) was prepared and formulated in hydrogel (MB 0.2%) to be used topically alone for treating BCCs <2 cm in diameter or to be combined with intralesional injection (ILI) of free MB 2% aqueous solution for treating BCCs ≥2 cm in diameter. A session was performed every 2 weeks until complete response (CR) of the lesion or for a maximum of six sessions. Clinical assessments of clinical improvement, dermatological photography, monthly follow-up visits for 6 months, and skin biopsy after 3 months of follow-up to confirm the response, recurrence, or both in cases in which the clinical evaluation was ambiguous. Seventeen patients of the 20 completed the study, 11 patients achieved CR with very good cosmetic outcome, photosensitizer tolerance, and minimal reported side effects. MB is a cheap promising alternative photosensitizer for PDT of nBCC.

  14. Nonlinear chemoconvection in the methylene-blue-glucose system: Two-dimensional shallow layers

    NASA Astrophysics Data System (ADS)

    Pons, A. J.; Batiste, O.; Bees, M. A.

    2008-07-01

    Interfacial hydrodynamic instabilities arise in a range of chemical systems. One mechanism for instability is the occurrence of unstable density gradients due to the accumulation of reaction products. In this paper we conduct two-dimensional nonlinear numerical simulations for a member of this class of system: the methylene-blue-glucose reaction. The result of these reactions is the oxidation of glucose to a relatively, but marginally, dense product, gluconic acid, that accumulates at oxygen permeable interfaces, such as the surface open to the atmosphere. The reaction is catalyzed by methylene-blue. We show that simulations help to disassemble the mechanisms responsible for the onset of instability and evolution of patterns, and we demonstrate that some of the results are remarkably consistent with experiments. We probe the impact of the upper oxygen boundary condition, for fixed flux, fixed concentration, or mixed boundary conditions, and find significant qualitative differences in solution behavior; structures either attract or repel one another depending on the boundary condition imposed. We suggest that measurement of the form of the boundary condition is possible via observation of oxygen penetration, and improved product yields may be obtained via proper control of boundary conditions in an engineering setting. We also investigate the dependence on parameters such as the Rayleigh number and depth. Finally, we find that pseudo-steady linear and weakly nonlinear techniques described elsewhere are useful tools for predicting the behavior of instabilities beyond their formal range of validity, as good agreement is obtained with the simulations.

  15. Adsorptional removal of methylene blue by guar gum-cerium (IV) tungstate hybrid cationic exchanger.

    PubMed

    Gupta, V K; Pathania, Deepak; Singh, Pardeep; Kumar, Amit; Rathore, B S

    2014-01-30

    Guar gum-cerium (IV) tungstate nanocomposite (GG/CTNC) cationic exchanger was synthesized using simple sol gel method. The GG/CTNC was characterized using X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectrophotometer (EDX). The XRD studies confirmed amorphous and fibrous in nature of GG/CTNC. The high percentage of oxygen in the nanocomposite material confirmed the functionality tungstate (WO4(-)). The ion exchange capacity of GG/CTNC for Na(+) ion was observed to be 1.30 mequivg(-1). The hybrid exchanger was used as potential adsorbent for the removal of methylene blue (MB) from aqueous system. The correlation coefficients value indicated a good fit of monolayer Langmuir model to the adsorption of methylene blue onto GG/CTNC. The adsorption kinetic study revealed that the adsorption process followed the pseudo second order kinetic. The Gibbs free energy (ΔG) values confirmed the spontaneous nature of adsorption process.

  16. [Adsorption of methylene blue from aqueous solution onto magnetic Fe3O4/ graphene oxide nanoparticles].

    PubMed

    Chang, Qing; Jiang, Guo-Dong; Hu, Meng-Xuan; Huang, Jia; Tang, He-Qing

    2014-05-01

    A simple ultrasound-assisted co-precipitation method was developed to prepare magnetic Fe3O4/graphene oxide (Fe3O4/ GO) nanoparticles. The characterization with transmission electron microscope (TEM) indicated that the products possessed small particle size. The hysteresis loop of the dried Fe3O4/GO nanoparticles demonstrated that the sample had typical features of superparamagnetic material. Batch adsorption studies were carried out to investigate the effects of the initial pH of the solution, the dosage of adsorbent, the contact time and temperature on the adsorption of methylene blue. The results indicated that the composites prepared could be used over a broad pH range (pH 6-9). The adsorption process was very fast within the first 25 min and the equilibrium was reached at 180 min. The adsorption equilibrium and kinetics data fitted well with the Langmuir isotherm model and the pseudo-second-order kinetic model. The adsorption process was a spontaneous and endothermic process in nature. The composite exhibited fairly high adsorption capacity (196.5 mg.g-1) of methylene blue at 313 K. In addition, the magnetic composite could be effectively and simply separated by using an external magnetic field, and then regenerated by hydrogen peroxide and recycled for further use. The results indicated that the adsorbent had a potential in the application of the dye wastewater treatment.

  17. Removal of methylene blue from aqueous solution by adsorption onto pineapple leaf powder.

    PubMed

    Weng, Chih-Huang; Lin, Yao-Tung; Tzeng, Tai-Wei

    2009-10-15

    The ability of an unconventional bio-adsorbent, pineapple leaf powder (PLP) for the adsorption of methylene blue (MB) from aqueous solution was studied. It was observed that intra-particle diffusion was involved in the adsorption process and that the kinetic data fitted well with a pseudo-second-order equation. Fitting parameters revealed that the rate of adsorption increased with decrease in dye concentration and decrease in ionic strength while the mixing speed did not have a significant effect on adsorption. The adsorption was favorable at higher pH and lower temperature, and the equilibrium data were well fitted by the Langmuir isotherm. The maximum adsorption capacity varied from 4.68 x 10(-4) to 9.28 x 10(-4)mol/g when pH increases from 3.5 to 9.5. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. The results revealed that this agricultural waste has potential to be used as an economical adsorbent for the removal of methylene blue from aqueous solution.

  18. Synthesis and characterization of magnetic palygorskite nanoparticles and their application on methylene blue remotion from water

    NASA Astrophysics Data System (ADS)

    Middea, Antonieta; Spinelli, Luciana S.; Souza, Fernando G.; Neumann, Reiner; Gomes, Otavio da F. M.; Fernandes, Thais L. A. P.; de Lima, Luiz C.; Barthem, Vitoria M. T. S.; de Carvalho, Fernanda V.

    2015-08-01

    Recently there has been considerable interest in magnetic sorbents materials, which is added excellent capabilities such as sorption and magnetic response to an applied field. Accordingly, palygorskite nanoparticles were covered by magnetite using a co-precipitation technique and characterized by: X-ray fluorescence (XRF), X-ray diffraction (XRD), surface analysing and scanning electron microscopy (SEM) with element analysis and mapping, particle size, pore surface area (BET), density, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and zeta potential. Additionally, magnetic properties were studied by SQUID magnetometer, magnetic force microscopy (MFM) and also using a simple experimental setup. Magnetic nanoparticles produced had average diameters in a nanometric range. The amount of iron present in the nanoparticles increased by six times after the magnetization and a superparamagnetic behavior was exhibited with high saturation magnetization, from 4.0 × 10-4 Am2/kg to about 20 Am2/kg. A weight loss was also observed around 277 °C-339 °C by TGA, indicating a structural change from magnetite to maghemite, which confirms the magnetization of palygorskite. Batch adsorption experiments were carried out for the removal of methylene blue cationic dye from aqueous solution using pure and covered by magnetite palygorskite nanoparticles as adsorbents. Furthermore, about 90% of methylene blue was removed within 3 min using magnetized palygorskite.

  19. A Possible Phenomenon of Persistence in Pseudomonas aeruginosa Treated with Methylene Blue and Red Light.

    PubMed

    Forte Giacobone, Ana Florencia; Ruiz Gale, Maria Fernanda; Hogert, Elsa Noemí; Oppezzo, Oscar Juan

    2016-09-01

    Planktonic Pseudomonas aeruginosa cells harvested in stationary phase were exposed to red light in the presence of methylene blue to study the potential occurrence of persistence in bacterial populations submitted to photodynamic antimicrobial therapy. Survival curves revealed the existence of small subpopulations of cells exhibiting increased ability to tolerate the treatment. These subpopulations were detected even using high concentrations of photosensitizer, whether added in a single step or following a fractionated scheme, and when the irradiation medium was modified to delay the photodecomposition of methylene blue. When cells grown from survivors to the treatment were cultured and exposed to red light and dye, their responses were similar to that of the original strain. These results exclude exhaustion of the photosensitizer and selection of resistant mutants as explanations for the features of the survival curves. Cells able to tolerate the treatment were found even when radiation was imparted at a high-dose rate. They exhibit a response typical of persisters, which tolerate antimicrobial agents due to transient and reversible changes in their phenotype, suggesting that persistence is a factor to consider upon evaluating the efficacy of photodynamic antimicrobial therapy.

  20. Hybrid multiwalled carbon nanotube--Laponite sorbent for removal of methylene blue from aqueous solutions.

    PubMed

    Loginov, Maksym; Lebovka, Nikolai; Vorobiev, Eugene

    2014-10-01

    The article discusses adsorption of methylene blue dye by novel hybrid sorbent consisting of Laponite and multiwalled carbon nanotubes. The sorbent was obtained by sonication of the aqueous suspensions of nanotubes at different concentrations of Laponite. The methods of the methylene blue adsorption, dead-end membrane filtration and environmental scanning electron microscopy were used for the sorbent characterization. It may be concluded from the results of filtration and adsorption experiments that sonication of mixed aqueous suspensions of Laponite and multiwalled carbon nanotubes leads to the formation of hybrid particles (ML-particles) with a core-shell structure. The size and the shape of hybrid particles were determined by nanotubes, while their adsorption properties were determined by Laponite particles attached to the surface of nanotubes. The Laponite content in hybrid particles was corresponding to the Laponite to nanotubes ratio in the initial suspension X(L)=0-1. Due to the presence of Laponite in the sorbent, its adsorbing capacity was much higher as compared to the adsorbing capacity of pure nanotubes, and it was directly proportional to the Laponite content. This sorbent may be used either as a purifying additive or as a filtering layer if it is deposited on the surface of a supporting membrane. Due to relatively large size of hybrid particles, they can be easily separated from the purified solution by filtration or centrifugation.

  1. Photocatalytic activity enhancement of anatase-graphene nanocomposite for methylene removal: Degradation and kinetics.

    PubMed

    Rezaei, Mostafa; Salem, Shiva

    2016-10-01

    In the present research, the TiO2-graphene nanocomposite was synthesized by an eco-friendly method. The blackberry juice was introduced to graphene oxide (GO) as a reducing agent to produce the graphene nano-sheets. The nanocomposite of anatase-graphene was developed as a photocatalyst for the degradation of methylene blue, owing to the larger specific surface area and synergistic effect of reduced graphene oxide (RGO). The UV spectroscopy measurements showed that the prepared nanocomposite exhibited an excellent photocatalytic activity toward the methylene blue degradation. The rate of electron transfer of redox sheets is much higher than that observed on GO, indicating the applicability of proposed method for the production of anatase-RGO nanocomposite for treatment of water contaminated by cationic dye. The prepared materials were characterized with Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area measurement, scanning electron microscopy and transmission electron microscopy. A facile and rapid route was applied for the uniform deposition of anatase nanoparticles on the sheets. The resulting nanocomposite contained nanoparticles with a mean diameter of 10nm. A mechanism for the photocatalytic activity of nanocomposite was suggested and the degradation reaction obeyed the second-order kinetics. It was concluded that the degradation kinetics is changed due to the reduction of GO in the presence of blackberry juice.

  2. Potential Biosorbent Derived from Calligonum polygonoides for Removal of Methylene Blue Dye from Aqueous Solution

    PubMed Central

    Nasrullah, Asma; Khan, Hizbullah; Khan, Amir Sada; Man, Zakaria; Muhammad, Nawshad; Khan, Muhammad Irfan; Abd El-Salam, Naser M.

    2015-01-01

    The ash of C. polygonoides (locally called balanza) was collected from Lakki Marwat, Khyber Pakhtunkhwa, Pakistan, and was utilized as biosorbent for methylene blue (MB) removal from aqueous solution. The ash was used as biosorbent without any physical or chemical treatment. The biosorbent was characterized by using various techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The particle size and surface area were measured using particle size analyzer and Brunauer-Emmett-Teller equation (BET), respectively. The SEM and BET results expressed that the adsorbent has porous nature. Effects of various conditions such as initial concentration of methylene blue (MB), initial pH, contact time, dosage of biosorbent, and stirring rate were also investigated for the adsorption process. The rate of the adsorption of MB on biomass sample was fast, and equilibrium has been achieved within 1 hour. The kinetics of MB adsorption on biosorbent was studied by pseudo-first- and pseudo-second-order kinetic models and the pseudo-second-order has better mathematical fit with correlation coefficient value (R2) of 0.999. The study revealed that C. polygonoides ash proved to be an effective, alternative, inexpensive, and environmentally benign biosorbent for MB removal from aqueous solution. PMID:25705714

  3. Extractive spectrophotometric determination of some nonsteroidal anti-inflammatory drugs using methylene blue.

    PubMed

    El-Kommos, Michael E; Mohamed, Niveen A; Hakiem, Ahmed F Abdel

    2013-01-01

    A simple, rapid, sensitive, and accurate extractive spectrophotometric method has been developed for the determination of seven nonsteroidal anti-inflammatory drugs (NSAIDs)--namely diclofenac sodium, ibuprofen, indomethacin, ketoprofen, ketorolac tromethamine, mefenamic acid, and naproxen-in pure forms as well as their pharmaceutical dosage forms (tablets, capsules, effervescent granules, syrups, oral drops, ampules, eye drops, gels, and suppositories). The method depends on the formation of an intensely colored ion-pair complex between the acidic drug and methylene blue in alkaline medium. The complex is stable and extractable into methylene chloride. All parameters were optimized. Beer-Lambert's law was obeyed in concentrations ranging from 0.04 to 9 microg/mL. Statistical analysis of the calibration data was carried out, and correlation coefficients were in the range from 0.9996 to 0.9998. The developed method was fully validated according to International Conference on Harmonization guidelines, and complied with U.S. Pharmacopeia guidelines. The proposed method was applied to the analysis of the investigated drugs in their pharmaceutical formulations, and good recoveries were obtained. The results obtained were compared with those of reported and official methods, and no significant differences were found with t- and F-tests. Interference effects of some compounds usually present in combination with NSAIDs were studied, and the tolerance limits of these compounds were determined. PMID:24000745

  4. Photocatalytic activity enhancement of anatase-graphene nanocomposite for methylene removal: Degradation and kinetics

    NASA Astrophysics Data System (ADS)

    Rezaei, Mostafa; Salem, Shiva

    2016-10-01

    In the present research, the TiO2-graphene nanocomposite was synthesized by an eco-friendly method. The blackberry juice was introduced to graphene oxide (GO) as a reducing agent to produce the graphene nano-sheets. The nanocomposite of anatase-graphene was developed as a photocatalyst for the degradation of methylene blue, owing to the larger specific surface area and synergistic effect of reduced graphene oxide (RGO). The UV spectroscopy measurements showed that the prepared nanocomposite exhibited an excellent photocatalytic activity toward the methylene blue degradation. The rate of electron transfer of redox sheets is much higher than that observed on GO, indicating the applicability of proposed method for the production of anatase-RGO nanocomposite for treatment of water contaminated by cationic dye. The prepared materials were characterized with Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area measurement, scanning electron microscopy and transmission electron microscopy. A facile and rapid route was applied for the uniform deposition of anatase nanoparticles on the sheets. The resulting nanocomposite contained nanoparticles with a mean diameter of 10 nm. A mechanism for the photocatalytic activity of nanocomposite was suggested and the degradation reaction obeyed the second-order kinetics. It was concluded that the degradation kinetics is changed due to the reduction of GO in the presence of blackberry juice.

  5. Development of new 5-(chromene-3-yl)methylene-2,4-thiazolidinediones as antimicrobial agents

    PubMed Central

    NASTASĂ, CRISTINA MARIANA; DUMA, MIHAELA; PÎRNĂU, ADRIAN; VLASE, LAURIAN; TIPERCIUC, BRÎNDUŞA; ONIGA, OVIDIU

    2016-01-01

    Background and aims In the context of the increasing phenomenon of microbial resistance to usual drugs, the development of new treatment strategies and new therapeutic protocols is a constant need. Thiazolidinedione and chromone represent two important scaffolds in medicinal chemistry due to their large pharmacological applicability. Methods We synthesized a new 5-(chromene-3-yl)methylene-2,4-thiazolidinedione starting from 6,8-dichloro-4-oxo-4H-chromene-3-carbaldehyde. Then, by treating with different α-bromoalkylarylketones, we obtained N-substituted derivatives. All new compounds were investigated for their antimicrobial potential, using the diffusion method, against Listeria monocytogenes ATCC 13932, Staphylococcus aureus ATCC 49444, Escherichia coli ATCC 25922, Salmonella typhimurium ATCC 14028 and Candida albicans ATCC 10231. Three concentrations, 10 mg/ml, 5 mg/ml and 1 mg/ml of compounds were used. The results were evaluated by the measurement of the inhibition zone diameters and compared to those of gentamicin and fluconazole respectively, as reference drugs. Results All new synthesized compounds were characterized using physico-chemical and spectrometric methods. They displayed modest to good antimicrobial activity. New molecules 8, 9 and 10 may represent promising candidates, showing zone inhibition diameters superior to those of reference drugs. Conclusions This work presents chemical synthesis, characterization and investigation of the antibacterial and antifungal potential of 5-(chromene-3-yl)methylene-2,4-thiazolidinedione derivatives, which may be worthy of future research for designing new chemical entities. PMID:27004035

  6. Potential biosorbent derived from Calligonum polygonoides for removal of methylene blue dye from aqueous solution.

    PubMed

    Nasrullah, Asma; Khan, Hizbullah; Khan, Amir Sada; Man, Zakaria; Muhammad, Nawshad; Khan, Muhammad Irfan; Abd El-Salam, Naser M

    2015-01-01

    The ash of C. polygonoides (locally called balanza) was collected from Lakki Marwat, Khyber Pakhtunkhwa, Pakistan, and was utilized as biosorbent for methylene blue (MB) removal from aqueous solution. The ash was used as biosorbent without any physical or chemical treatment. The biosorbent was characterized by using various techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The particle size and surface area were measured using particle size analyzer and Brunauer-Emmett-Teller equation (BET), respectively. The SEM and BET results expressed that the adsorbent has porous nature. Effects of various conditions such as initial concentration of methylene blue (MB), initial pH, contact time, dosage of biosorbent, and stirring rate were also investigated for the adsorption process. The rate of the adsorption of MB on biomass sample was fast, and equilibrium has been achieved within 1 hour. The kinetics of MB adsorption on biosorbent was studied by pseudo-first- and pseudo-second-order kinetic models and the pseudo-second-order has better mathematical fit with correlation coefficient value (R (2)) of 0.999. The study revealed that C. polygonoides ash proved to be an effective, alternative, inexpensive, and environmentally benign biosorbent for MB removal from aqueous solution.

  7. Kinetics and thermodynamics of adsorption of methylene blue by a magnetic graphene-carbon nanotube composite

    NASA Astrophysics Data System (ADS)

    Wang, Peifang; Cao, Muhan; Wang, Chao; Ao, Yanhui; Hou, Jun; Qian, Jin

    2014-01-01

    A solvothermal method was employed to prepare a novel magnetic composite adsorbent composed of graphene, multi-walled carbon nanotubes (MWCNTs) and Fe3O4 nanoparticles. The prepared adsorbents were characterized by X-ray diffraction, scanning electron microscopy and X-ray fluorescence spectrometry and Fourier transform infrared spectroscopy. Fourier transform infrared spectroscopy and the particle size distribution of the samples before and after adsorption was also carried out. The performance of as-prepared composites was investigated by the adsorption of dye methylene blue. Results showed that the maximum adsorption capacity of the samples was up to 65.79 mg g-1, which was almost equal to the sum of magnetic graphene and magnetic MWCNTs. The effect of pH and temperature on the adsorption performance of methylene blue onto the magnetic adsorbents was investigated. The kinetic was well-described by pseudo-second-order and intraparticle diffusion model, while the isotherm obeyed the Langmuir isotherm. Furthermore, the as-prepared composites were found to be regenerative and reusable. The application in the treatment of an artificial dye wastewater and its cost estimation were also discussed. Therefore, the as-prepared magnetic composites can be severed as a potential adsorbent for removal of dye pollutant, owing to its high adsorption performance, magnetic separability and efficient recyclable property.

  8. Treatment of dilute methylene blue-containing wastewater by coupling sawdust adsorption and electrochemical regeneration.

    PubMed

    Bouaziz, I; Chiron, C; Abdelhedi, R; Savall, A; Groenen Serrano, K

    2014-01-01

    In the present work, the coupling of adsorption and electrochemical oxidation on a boron-doped diamond (BDD) electrode to treat solutions containing dyes is studied. This coupling may be convenient for the treatment of diluted pollutant that is limited by the low rate of electrooxidation due to mass-transfer limitation. A pre-concentration step by adsorption could minimize the design of the electrochemical reactor. The adsorbent chosen was mixed with softwood sawdust, and methylene blue was chosen as the model dye molecule. Isotherms of adsorption and kinetics were investigated as well as the effects of current density and regeneration time. The BDD electrochemical oxidation of methylene blue adsorbed onto sawdust led simultaneously to its degradation and sawdust regeneration for the next adsorption. It was observed that multiple adsorption and electrochemical regeneration cycles led to an enhancement of adsorption capacity of the sawdust. This study demonstrated that adsorption–electrochemical degradation coupling offers a promising approach for the efficient elimination of organic dyes from wastewater.

  9. Headspace gas chromatographic determination of methylene chloride in decaffeinated tea and coffee, with electrolytic conductivity detection.

    PubMed

    Page, B D; Charbonneau, C F

    1984-01-01

    A headspace gas chromatographic procedure is described for the determination of methylene chloride (MC) in decaffeinated tea and coffee. The tea or coffee sample, with added methylene bromide (MB) internal standard, is equilibrated for 1.5 h at 100 degrees C in aqueous sodium sulfate before manual headspace sampling. MC and MB are separated on a Porasil A column at 160 degrees C and detected by using a Coulson electrolytic conductivity detector. For coffee and tea samples spiked at 1.3 ppm MC, as well as commercially decaffeinated teas and coffees containing up to 8 ppm MC, coefficients of variation were 10% or less. For decaffeinated teas, problems involving sample homogeneity and loss of MC before sealing the headspace vial had to be overcome. Similar problems with decaffeinated instant and ground coffees were minimal. The headspace procedure was superior to a previously reported distillation technique. MC was readily detected at 0.05 ppm. Fourteen decaffeinated teas and 15 decaffeinated coffees were analyzed; MC was detected at levels that ranged up to 15.9 and 4.0 ppm, respectively. PMID:6469909

  10. Removal of methylene blue from aqueous solution by adsorption onto pineapple leaf powder.

    PubMed

    Weng, Chih-Huang; Lin, Yao-Tung; Tzeng, Tai-Wei

    2009-10-15

    The ability of an unconventional bio-adsorbent, pineapple leaf powder (PLP) for the adsorption of methylene blue (MB) from aqueous solution was studied. It was observed that intra-particle diffusion was involved in the adsorption process and that the kinetic data fitted well with a pseudo-second-order equation. Fitting parameters revealed that the rate of adsorption increased with decrease in dye concentration and decrease in ionic strength while the mixing speed did not have a significant effect on adsorption. The adsorption was favorable at higher pH and lower temperature, and the equilibrium data were well fitted by the Langmuir isotherm. The maximum adsorption capacity varied from 4.68 x 10(-4) to 9.28 x 10(-4)mol/g when pH increases from 3.5 to 9.5. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. The results revealed that this agricultural waste has potential to be used as an economical adsorbent for the removal of methylene blue from aqueous solution. PMID:19447547

  11. An Exocyclic Methylene Group Acts As a Bioisostere of the 2′-Oxygen Atom in LNA

    SciTech Connect

    Seth, Punit P.; Allerson, Charles R.; Berdeja, Andres; Siwkowski, Andrew; Pallan, Pradeep S.; Gaus, Hans; Prakash, Thazha P.; Watt, Andrew T.; Egli, Martin; Swayze, Eric E.

    2010-12-07

    We show for the first time that it is possible to obtain LNA-like (Locked Nucleic Acid 1) binding affinity and biological activity with carbocyclic LNA (cLNA) analogs by replacing the 2{prime}-oxygen atom in LNA with an exocyclic methylene group. Synthesis of the methylene-cLNA nucleoside was accomplished by an intramolecular cyclization reaction between a radical at the 2{prime}-position and a propynyl group at the C-4{prime} position. Only methylene-cLNA modified oligonucleotides showed similar thermal stability and mismatch discrimination properties for complementary nucleic acids as LNA. In contrast, the close structurally related methyl-cLNA analogs showed diminished hybridization properties. Analysis of crystal structures of cLNA modified self-complementary DNA decamer duplexes revealed that the methylene group participates in a tight interaction with a 2{prime}-deoxyribose residue of the 5{prime}-terminal G of a neighboring duplex, resulting in the formation of a CH...O type hydrogen bond. This indicates that the methylene group retains a negative polarization at the edge of the minor groove in the absence of a hydrophilic 2{prime}-substituent and provides a rationale for the superior thermal stability of this modification. In animal experiments, methylene-cLNA antisense oligonucleotides (ASOs) showed similar in vivo activity but reduced toxicity as compared to LNA ASOs. Our work highlights the interchangeable role of oxygen and unsaturated moieties in nucleic acid structure and emphasizes greater use of this bioisostere to improve the properties of nucleic acids for therapeutic and diagnostic applications.

  12. γ-Fe2O3 nanocrystals-anchored macro/meso-porous graphene as a highly efficient adsorbent toward removal of methylene blue.

    PubMed

    Zhang, Lian Ying; Zhang, Wenlin; Zhou, Zhiqin; Li, Chang Ming

    2016-08-15

    An adsorbent, γ-Fe2O3 nanocrystals-anchored macro/meso-porous graphene was synthesized by metal etching approach toward removal of methylene blue, exhibiting rapid adsorption rate, high adsorption capacity and good recyclability, thus holding a great promise for treatment of methylene blue in wastewater. PMID:27218808

  13. Use of TOF-SIMS to study adsorption and loading behavior of methylene blue and papain in a nano-porous silicon layer.

    PubMed

    Kempson, Ivan M; Barnes, Timothy J; Prestidge, Clive A

    2010-02-01

    TOF-SIMS was applied to study the cross-sectional distribution of methylene blue and papain in porous silicon layers. Elemental and molecular information were used to study their distributions in the porous region and the chemistry of their adsorption. Methylene blue (MW = 284 Da) penetrated to the base to the pores. Positive ions (SiCH(3)(+)) suggest methylene blue binds to the substrate via its methyl groups. Negative fragments (SiOSH(3)(-) and SiO(2)SCH(-)) also suggested chemisorption via O bridging of the substrate Si and methylene blue S. The larger Papain molecule (23,406 Da) distributed itself in a similar manner to methylene blue demonstrating larger molecules can be effectively incorporated into such pore structures.

  14. Sulfonamide antibiotic removal and nitrogen recovery from synthetic urine by the combination of rotating advanced oxidation contactor and methylene urea synthesis process.

    PubMed

    Fukahori, S; Fujiwara, T; Ito, R; Funamizu, N

    2015-01-01

    The combination of nitrogen recovery and pharmaceutical removal processes for livestock urine treatment were investigated to suppress the discharge of pollutants and recover nitrogen as resources. We combined methylene urea synthesis from urea and adsorption and photocatalytic decomposition of sulfonamide antibiotic using rotating advanced oxidation contactor (RAOC) contained for obtaining both safe fertilizer and reclaimed water. The methylene urea synthesis could recover urea in synthetic urine, however, almost all sulfonamide antibiotic was also incorporated, which is unfavorable from a safety aspect if the methylene urea is to be used as fertilizer. Conversely, RAOC could remove sulfonamide antibiotic without consuming urea. It was also confirmed that the methylene urea could be synthesized from synthetic urine treated by RAOC. Thus, we concluded that RAOC should be inserted prior to the nitrogen recovery process for effective treatment of urine and safe use of methylene urea as fertilizer.

  15. Methylene blue not ferrocene: Optimal reporters for electrochemical detection of protease activity.

    PubMed

    González-Fernández, Eva; Avlonitis, Nicolaos; Murray, Alan F; Mount, Andrew R; Bradley, Mark

    2016-10-15

    Electrochemical peptide-based biosensors are attracting significant attention for the detection and analysis of proteins. Here we report the optimisation and evaluation of an electrochemical biosensor for the detection of protease activity using self-assembled monolayers (SAMs) on gold surfaces, using trypsin as a model protease. The principle of detection was the specific proteolytic cleavage of redox-tagged peptides by trypsin, which causes the release of the redox reporter, resulting in a decrease of the peak current as measured by square wave voltammetry. A systematic enhancement of detection was achieved through optimisation of the properties of the redox-tagged peptide; this included for the first time a side-by-side study of the applicability of two of the most commonly applied redox reporters used for developing electrochemical biosensors, ferrocene and methylene blue, along with the effect of changing both the nature of the spacer and the composition of the SAM. Methylene blue-tagged peptides combined with a polyethylene-glycol (PEG) based spacer were shown to be the best platform for trypsin detection, leading to the highest fidelity signals (characterised by the highest sensitivity (signal gain) and a much more stable background than that registered when using ferrocene as a reporter). A ternary SAM (T-SAM) configuration, which included a PEG-based dithiol, minimised the non-specific adsorption of other proteins and was sensitive towards trypsin in the clinically relevant range, with a Limit of Detection (LoD) of 250pM. Kinetic analysis of the electrochemical response with time showed a good fit to a Michaelis-Menten surface cleavage model, enabling the extraction of values for kcat and KM. Fitting to this model enabled quantitative determination of the solution concentration of trypsin across the entire measurement range. Studies using an enzyme inhibitor and a range of real world possible interferents demonstrated a selective response to trypsin

  16. Methylene blue not ferrocene: Optimal reporters for electrochemical detection of protease activity.

    PubMed

    González-Fernández, Eva; Avlonitis, Nicolaos; Murray, Alan F; Mount, Andrew R; Bradley, Mark

    2016-10-15

    Electrochemical peptide-based biosensors are attracting significant attention for the detection and analysis of proteins. Here we report the optimisation and evaluation of an electrochemical biosensor for the detection of protease activity using self-assembled monolayers (SAMs) on gold surfaces, using trypsin as a model protease. The principle of detection was the specific proteolytic cleavage of redox-tagged peptides by trypsin, which causes the release of the redox reporter, resulting in a decrease of the peak current as measured by square wave voltammetry. A systematic enhancement of detection was achieved through optimisation of the properties of the redox-tagged peptide; this included for the first time a side-by-side study of the applicability of two of the most commonly applied redox reporters used for developing electrochemical biosensors, ferrocene and methylene blue, along with the effect of changing both the nature of the spacer and the composition of the SAM. Methylene blue-tagged peptides combined with a polyethylene-glycol (PEG) based spacer were shown to be the best platform for trypsin detection, leading to the highest fidelity signals (characterised by the highest sensitivity (signal gain) and a much more stable background than that registered when using ferrocene as a reporter). A ternary SAM (T-SAM) configuration, which included a PEG-based dithiol, minimised the non-specific adsorption of other proteins and was sensitive towards trypsin in the clinically relevant range, with a Limit of Detection (LoD) of 250pM. Kinetic analysis of the electrochemical response with time showed a good fit to a Michaelis-Menten surface cleavage model, enabling the extraction of values for kcat and KM. Fitting to this model enabled quantitative determination of the solution concentration of trypsin across the entire measurement range. Studies using an enzyme inhibitor and a range of real world possible interferents demonstrated a selective response to trypsin

  17. [Lymph node preparation in colorectal cancer. Ex vivo methylene blue injection as a novel technique to improve lymph node visualization].

    PubMed

    Märkl, B; Kerwel, T; Jähnig, H; Anthuber, M; Arnholdt, H

    2008-07-01

    The UICC requires investigation of a minimum of 12 lymph nodes for adequate lymph node staging in colorectal cancer. Despite that, many authors recommend investigation of a larger number, and different techniques, such as fat clearance, have therefore been developed. In this study we introduce a novel technique involving ex vivo lymph node staining with intraarterial methylene blue injection in colon cancer. We compared 14 cases in which methylene injection was used with 14 cases from our records in which conventional investigation techniques were applied. The lymph node harvest differed highly significantly (p<0.001) between the two groups, with average numbers of 28+/-7 and 14+/-3 in the methylene blue group and the unstained group, respectively. The largest difference occurred in the size group 2-4 mm (191 vs 70 lymph nodes). In 6 cases in the unstained group additional embedding of fatty tissue was necessary to reach an adequate number of investigated lymph nodes. Methylene blue injection is a novel and highly effective method that will improve lymph node preparation in colorectal cancer.

  18. Developmental toxicity of copper chloride, methylene chloride, and 6-aminonicotinamide to embryos of the grass shrimp Palaemonetes pugio

    SciTech Connect

    Rayburn, J.R.; Fisher, W.S.

    1999-05-01

    Embryos of estuarine grass shrimp Palaemonetes pugio have demonstrated sensitivity to various solvents and petroleum products, indicating utility for evaluating estuarine contamination. Testing was performed to establish concentration-response curves for methylene chloride, copper chloride, and 6-aminonicotinamide, three known teratogenic chemicals. Two exposure periods were used, 4 d and 12 d, and both periods extended through hatching. The average 4-d LC50 values for methylene chloride, copper chloride, and 6-aminonicotinamide were 0.071% v/v, 1.82 mg/L, and 0.21 mg/ml, respectively. The average 12-d LC50 values for methylene chloride, copper chloride, and 6-aminonicotinamide were 0.031% v/v, 1.44 mg/L, and 0.057 mg/ml, respectively. Eye malformations were observed with embryos exposed to concentrations greater than 3 mg/L copper chloride or greater than 0.07% v/v methylene chloride. Very few abnormalities were observed in embryos exposed to 6-aminonicotinamide. Abnormal larval development was found with exposure to copper chloride at concentrations greater than 1 mg/L. The sensitivity and low variability found here further supports the development of these relatively simple methods using grass shrimp embryos. Establishment of sublethal developmental endpoints warrants further investigation because of their potential correspondence to mechanisms of toxic action.

  19. 40 CFR 721.10626 - 1,4-Butanediol, polymer with substituted alkane and substituted methylene biscarbomonocycle, 2...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1,4-Butanediol, polymer with substituted alkane and substituted methylene biscarbomonocycle, 2-hydroxyalkyl acrylate-blocked (generic). 721.10626 Section 721.10626 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES...

  20. Kinetics analysis for development of a rate constant estimation model for ultrasonic degradation reaction of methylene blue.

    PubMed

    Kobayashi, Daisuke; Honma, Chiemi; Matsumoto, Hideyuki; Takahashi, Tomoki; Kuroda, Chiaki; Otake, Katsuto; Shono, Atsushi

    2014-07-01

    Ultrasound has been used as an advanced oxidation method for wastewater treatment. Sonochemical degradation of organic compounds in aqueous solution occurs by pyrolysis and/or reaction with hydroxyl radicals. Moreover, kinetics of sonochemical degradation has been proposed. However, the effect of ultrasonic frequency on degradation rate has not been investigated. In our previous study, a simple model for estimating the apparent degradation rate of methylene blue was proposed. In this study, sonochemical degradation of methylene blue was performed at various frequencies. Apparent degradation rate constant was evaluated assuming that sonochemical degradation of methylene blue was a first-order reaction. Specifically, we focused on effects of ultrasonic frequency and power on rate constant, and the applicability of our proposed model was demonstrated. Using this approach, maximum sonochemical degradation rate was observed at 490 kHz, which agrees with a previous investigation into the effect of frequency on the sonochemical efficiency value evaluated by KI oxidation dosimetry. Degradation rate increased with ultrasonic power at every frequency. It was also observed that threshold power must be reached for the degradation reaction to progress. The initial methylene blue concentration and the apparent degradation rate constant have a relation of an inverse proportion. Our proposed model for estimating the apparent degradation rate constant using ultrasonic power and sonochemical efficiency value can apply to this study which extended the frequency and initial concentration range.

  1. DEMONSTRATION OF N-METHYL PYRROLIDONE (NMP) AS A POLLUTION PREVENTION ALTERNATIVE TO PAINT STRIPPING WITH METHYLENE CHLORIDE

    EPA Science Inventory

    This objective of this paper is to demonstrate that NMP is a viable pollution prevention alternative to methylene chloride. Maine Corps Logistics Base (MCLB), Albany, GA, USA was the host site for the demonstration. MCLB's primary function is maintenance of military ground supp...

  2. Desorption and photodegradation of methylene blue from modified sugarcane bagasse surface by acid TiO2 hydrosol

    NASA Astrophysics Data System (ADS)

    Yu, Jun-Xia; Chi, Ru-An; Guo, Jia; Zhang, Yue-Fei; Xu, Zhi-Gao; Xiao, Chun-Qiao

    2012-02-01

    Waste sugarcane bagasse (SCB) was modified by pyromellitic dianhydride to improve its adsorption capacity for cationic dyes. Results showed that the adsorption capacity of the modified SCB for methylene blue was 564 mg g-1, which was about 12 times than that obtained on the unmodified SCB. Methylene blue loaded modified SCB was regenerated by a self-clean eluent: TiO2 hydrosol with pH ranged from 1 to 4, and HNO3 solution with the same pH range was tested at the same time for comparison. Results showed that desorption kinetics of methylene blue in the hydrosol systems fit two-step kinetic model and controlled mainly by the slow step. As a self-clean eluent, acid hydrosol could firstly desorb and then photodegrade methylene blue under sunlight irradiation. After five desorption-photodegradation cycles, 78.3% of the absorbed dyes could be desorbed by using hydrosol (pH 2) as eluent. The hydrosol could be continuously used in desorption and photodegradation process, which would economize large volume of the eluent and moreover it would not bring secondary pollution.

  3. Catalytic ozone aqueous decomposition of methylene blue using composite metal oxides

    NASA Astrophysics Data System (ADS)

    Liu, Xuan; Hou, Yongjiang; Guo, Jie; Wang, Yaquan; Zuo, Qian; Wang, Chunyu

    2015-07-01

    By using the method of co-precipitation, Fe-Mn, Al-Mn, Al-Mg composite metal oxides were prepared. Using X-ray diffractometer(XRD), the phases of catalysts synthesized were observed to be Mn3O4 and Fe2O3. With the increase of the calcination temperature, Mn3O4 was gradually transformed into Mn2O3. The experimental results show that: the best catalyst is the Fe-Mn composite metal oxide with the calcination temperature of 650 °C. In this experimental condition, when the ozone amount was 1.92mg/min, and the dosage of catalyst was 0.5g, the removal rate of methylene blue (MB) was the best. The decolorization rate can reach to 100%. Compared with the effect of ozonation alone, the total organic carbon removal rate increased from 29.19% up to 65.78% after adding catalysts.

  4. Epidemic of asthma in a wood products plant using methylene diphenyl diisocyanate.

    PubMed

    Woellner, R C; Hall, S; Greaves, I; Schoenwetter, W F

    1997-01-01

    Eighteen employees with lower respiratory symptoms later confirmed to be occupational asthma were referred for evaluation. All were employees of a single wood products plant using heated methylene diphenyl diisocyanate (MDI) in the manufacture of a synthetic wood product. Of the 18, 15 had no prior airway symptoms or other known bronchial injury, and 16 had positive methacholine bronchial provocation tests. All cases occurred during a 2.5-year period after exposure to a new manufacturing process using steam-heated MDI resin in a new manufacturing facility. Initially, employees developed symptoms related to the start-up process in the plant, with possible higher MDI exposures and probable higher resin temperatures. Later, most employees who developed new symptoms worked in areas of the plant where they were exposed mostly to heated boards. This suggests MDI sensitization arising at lower temperatures than previously considered likely for this substance.

  5. Comparative adsorption isotherms and modeling of methylene blue onto activated carbons

    NASA Astrophysics Data System (ADS)

    Belhachemi, Meriem; Addoun, Fatima

    2011-12-01

    The adsorption of methylene blue (MB) on activated carbons prepared from date stones with different degree of activation has been investigated. Equilibrium adsorption data of MB was carried out at 298 K. Four isotherm models (Freundlich, Langmuir, Redlich-Peterson and Sips) were tested for modeling the adsorption isotherms by nonlinear method. The three-parameter equations (Redlich-Peterson and Sips) showed more applicability than the two-parameter equations (Freundlich and Langmuir), which can be explained by the fact that these have three adjustable parameters. The best fit was achieved with the Redlich-Peterson equation according to the high value of correlation coefficient. All the samples were capable of retaining the MB, with the best result being reached by the sample with higher burn-off. Date stones activated carbon showed high adsorption capacity of 460 mg/g, calculated from the Sips isotherm model.

  6. Methylene blue as an early diagnostic marker for oral precancer and cancer.

    PubMed

    Riaz, Akhtar; Shreedhar, Balasundari; Kamboj, Mala; Natarajan, S

    2013-12-01

    Oral cancer is one of the most common neoplasm's and is ranked eighth in the cancer incidence worldwide. Early detection is of critical importance because survival rates markedly improve. In vivo staining is a simple, inexpensive, and fairly sensitive method. Involved 120 patients (50 with Premalignant Lesion, 50 with OSCC and 20 controls) stained by Methylene Blue (MB). The results of MB uptake were compared with a simultaneous biopsy of these lesions. Pathologically confirmed precancers and cancers were the positive targets of this screening, while hyperkeratosis without dysplasia and no evidence of malignancy were sorted as negative subjects of screening. The results revealed sensitivity of 91.4%, specificity of 66.6%, positive predictive value 97.7% and negative predictive value 33% leading to diagnostic accuracy of MB stain to 90%. We state that MB staining is useful diagnostic tool in community oral cancer screening programmes for high-risk individuals.

  7. Adsorption characteristics of methylene blue onto agricultural wastes lotus leaf in bath and column modes.

    PubMed

    Han, Xiuli; Wang, Wei; Ma, Xiaojian

    2011-01-01

    The adsorption potential of lotus leaf to remove methylene blue (MB) from aqueous solution was investigated in batch and fixed-bed column experiments. Langmuir, Freundlich, Temkin and Koble-Corrigan isotherm models were employed to discuss the adsorption behavior. The results of analysis indicated that the equilibrium data were perfectly represented by Temkin isotherm and the Langmuir saturation adsorption capacity of lotus leaf was found to be 239.6 mg g(-1) at 303 K. In fixed-bed column experiments, the effects of flow rate, influent concentration and bed height on the breakthrough characteristics of adsorption were discussed. The Thomas and the bed-depth/service time (BDST) models were applied to the column experimental data to determine the characteristic parameters of the column adsorption. The two models were found to be suitable to describe the dynamic behavior of MB adsorbed onto the lotus leaf powder column.

  8. Effect of a magnetic field on the adsorptive removal of methylene blue onto wheat straw biochar.

    PubMed

    Li, Guoting; Zhu, Weiyong; Zhang, Chunyu; Zhang, Shen; Liu, Lili; Zhu, Lingfeng; Zhao, Weigao

    2016-04-01

    Biochar pyrolyzed from wheat straw was innovatively used for the adsorptive removal of cationic dye methylene blue through exposure to a magnetic field. The adsorption capability of the biochar pyrolyzed at 200 °C exceeded that of samples pyrolyzed at higher temperatures. The surface acidic functional groups of wheat straw biochar were deduced to be more sensitive to the effects of the external magnetic field. The enhancement of the magnetic field achieved by increases in the initial dye concentration, and a decrease in the biochar dosage and solution pH, were more significant compared with those caused by other conditions. Kinetic experiments indicated that chemisorption occurred during adsorption. The qmax values for dye adsorption without, and with, an external magnetic field were found to be 46.6 and 62.5mg/g, respectively. These demonstrated that wheat straw biochar could be used for the efficient adsorption of pollutants when assisted by an external magnetic field.

  9. Preparation of Fe3O4 Nanoparticles and Removal of Methylene Blue through Adsorption

    NASA Astrophysics Data System (ADS)

    Trujillo Hernandez, J. S.; Aragón Muriel, A.; Tabares, J. A.; Pérez Alcázar, G. A.; Bolaños, A.

    2015-07-01

    In this work, we studied the catalytic activity, structural properties, and behavior of a Fe3O4 magnetic system. The Fe3O4 nanoparticles were prepared by the thermal decomposition method. X-ray diffraction confirmed the presence of a structural Fe3O4 phase, where acicular shape of the grains is shown. Transmission Mossbauer spectroscopy showed a wide distribution of particle sizes at room temperature, some of these present superparamagnetic behavior and are responsible of paramagnetic sites. The hysteresis loops obtained by the use of a vibrating sample magnetometer showed that these nanoparticles exhibit superparamagnetic behavior. However, the cycles present a significant contribution from a ferrimagnetic component at 2 K, which agrees with Mossbauer results. Through scanning electron microscopy, a tendency to the agglomeration of nanoparticles was observed. Nanoparticle activity in the degradation of methylene blue (MB) was studied through fluorescence spectroscopy, finding dye adsorption properties.

  10. Study on the methylene blue adsorption from wastewaters by pore-expanded calcium fluoride sludge adsorbent.

    PubMed

    Hong, Junming; Lin, Bing; Hong, Gui-Bing; Chang, Chang-Tang

    2014-04-01

    The adsorption of methylene blue (MB) onto pore-expanded calcium fluoride sludge (ECF) by the batch adsorption technique was investigated. The results showed that the adsorption capacity increased with increasing MB concentration but decreased as pH was increased. In order to investigate the adsorption mechanisms, three simplified isotherm models and kinetic models were used in this study. The best-fit adsorption isotherm was achieved with the Temkin model. Furthermore, the pseudo-second-order kinetic model agreed very well with the dynamical behavior for the adsorption of MB onto ECF. Thermodynamic studies revealed that the adsorption process of MB onto ECF was spontaneous and exothermic. The results indicated that ECF adsorbed MB efficiently and could be used as a waste adsorbent for the removal of cationic dyes in wastewater treatment.

  11. Removal of Methylene Blue and Orange-G from Waste Water Using Magnetic Biochar

    NASA Astrophysics Data System (ADS)

    Mubarak, N. M.; Fo, Y. T.; Al-Salim, Hikmat Said; Sahu, J. N.; Abdullah, E. C.; Nizamuddin, S.; Jayakumar, N. S.; Ganesan, P.

    2015-04-01

    The study on the removal of methylene blue (MB) and orange-G dyes using magnetic biochar derived from the empty fruit bunch (EFB) was carried out. Process parameters such as pH, adsorbent dosage, agitation speed and contact time were optimized using Design-Expert Software v.6.0.8. The statistical analysis reveals that the optimum conditions for the maximum adsorption of MB are at pH 2 and pH 10, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. While for orange-G, at pH 2, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. The maximum adsorption capacity of 31.25 mg/g and 32.36 mg/g for MB and orange-G respectively. The adsorption kinetic for both dyes obeyed pseudo-second order.

  12. Equilibrium models and kinetic for the adsorption of methylene blue on Co-hectorites.

    PubMed

    Ma, Jun; Jia, Yong-Zhong; Jing, Yan; Sun, Jin-He; Yao, Ying; Wang, Xiao-Hua

    2010-03-15

    The adsorption of methylene blue (MB) onto the surface of cobalt doping hectorite (Co-hectorite) was systematically studied. The physical properties of Co-hectorites were investigated, where characterizations were carried out by X-ray diffraction (XRD) and Electron Diffraction Spectrum (EDS) techniques, and morphology was examined by nitrogen adsorption. The sample with a Co content 5% (m/m) had a higher specific surface area than other Co-hectorites. The pore diameters were distributed between 2.5 and 5.0 nm. The adsorption results revealed that Co-hectorite surfaces possessed effective interactions with MB and bases, and greatest adsorption capacity achieved with Co content 5%, where the best-fit isotherm model was the Langmuir adsorption model. Kinetic studies were fitted to the pseudo-second-order kinetic model. The intraparticle diffusion was not the rate-limiting step for the whole reaction.

  13. Methylene blue adsorption from aqueous solution by activated carbon: effect of acidic and alkaline solution treatments.

    PubMed

    Ijagbemi, Christianah O; Chun, Ji I; Han, Da H; Cho, Hye Y; O, Se J; Kim, Dong S

    2010-01-01

    The removal of Methylene Blue (MB) from aqueous solution using activated carbon (AC) has been investigated. Adsorption experiments were conducted and the maximum adsorption capacity was determined. The effect of experimental parameters such as pH, dye concentration and temperature were studied on the adsorption process. Equilibrium data were mathematically modeled using the Langmuir and Freundlich adsorption models to describe the equilibrium isotherms at different dye concentrations and temperature. Parameters of best-fit model were calculated and discussed. To understand the mechanism of adsorption, kinetic models were employed to follow the adsorption processes; the pseudo-first-order best described the adsorption of MB onto AC. It was found that pH plays a major role in the adsorption process; adsorption capacity was influenced by the physical and surface chemical properties of carbon and the pH of the solution. 99.0% MB removal was achieved at equilibrium.

  14. Adsorptive performance for methylene blue of magnetic Ni@activated carbon nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Panfeng; Xu, Jingcai; Zhang, Beibei; Li, Jing; Jin, Hongxiao; Jin, Dingfeng; Peng, Xiaoling; Hong, Bo; Gong, Jie; Ge, Hongliang; Wang, Xinqing

    2015-11-01

    Owing to the unique microporous structure and high specific surface area, activated carbon (AC) can act as a good candidate for functional materials. In this paper, Ni@AC magnetic nanocomposites with excellent magnetic response are synthesized by the hydrothermal method. All Ni@AC nanocomposites present ferromagnetism and Ni nanoparticles exist in the pores of AC. The saturation magnetization (Ms) increases with the increasing content of Ni, while the specific surface area and pore volume decrease. The S-50 sample possesses the parameters of the specific surface area of 1156.8 m2 ṡ g-1 and Ms of 3.5 emu/g. Furthermore, the methylene blue (MB) removal analysis indicates that 99% MB can be adsorbed in 50 min. The as-prepared Ni@AC nanocomposites present good adsorptive capacity of MB and can be separated easily from water by magnetic separation technique.

  15. Supramolecular hybrids of polytungstates and their adsorption properties for methylene blue

    NASA Astrophysics Data System (ADS)

    Liu, Yunping; Zheng, Ran; Han, Zhangang; Gong, Kaining; He, Xueli; Zhai, Xueliang

    2015-11-01

    Two supramolecular hybrids [Ni(mbpy)3]2[V2W4O19]·6H2O (1) and [Ni(mbpy)3]2[VW12O40] (2) (mbpy=4,4ʹ-dimethyl-2,2ʹ-bipyridyl) had been synthesized and characterized. Single crystal X-ray diffraction analyses revealed that the anionic moieties in two hybrids belong to typical Lindqvist and α-Keggin-type structures, respectively. The counter ion [Ni(mbpy)3]2+ units were anchored to the polyanions via non-covalent intermolecular interactions. These supramolecular hybrids exhibit reversible adsorption-desorption performance for organic dye methylene blue (MB). Hybrid 2 shows a fast adsorption behavior towards MB and a relatively high value can be reached within 5 min in dark. Both 1 and 2 are structurally stable and can be easily separated from the reaction system for reuse.

  16. Reliability of assessing dye penetration along root canal fillings using methylene blue.

    PubMed

    Souza, Erick Miranda; Pappen, Fernanda Geraldes; Shemesh, Hagay; Bonanato-Estrela, Cristiane; Bonetti-Filho, Idomeo

    2009-12-01

    Methylene blue (MB) remains the most frequently used tracer for dye penetration tests of endodontic fillings, despite its chemical reactions with different materials. This study checked whether dye penetration displayed by MB is comparable to Rhodamine B (RB). One hundred and seventy-two root canals were filled with gutta-percha and six sealers. Samples were covered with nail varnish except for the apical area, and immersed in MB or RB solutions under negative pressure. After 24 h, roots were bisected, photographed and the maximal dye penetration recorded. Dye penetrations displayed by MB and RB were compared (Newman-Keuls test). MB and RB displayed comparable results for groups filled with AH Plus, EndoREZ and Polifil (P > 0.05). For Endofill, Sealer 26 and Sealapex, a significant lower dye penetration was observed when MB was used (P < 0.05). Laboratory tests using MB for measuring dye penetration through filled root canals can result in misleading conclusions.

  17. A Silver Nanoparticle-Modified Evanescent Field Optical Fiber Sensor for Methylene Blue Detection

    PubMed Central

    Luo, Ji; Yao, Jun; Lu, Yonggang; Ma, Wenying; Zhuang, Xuye

    2013-01-01

    A silver nanoparticle-modified evanescent field optical fiber sensor based on a MEMS microchannel chip has been successfully fabricated. Experimental results show that the sensor response decreases linearly with increasing concentration of analyte. Over a range of methylene blue concentrations from 0 to 0.4 μmol/mL, the sensor response is linear (R = 0.9496). A concentration variation of 0.1 μmol/mL can cause an absorbance change of 0.402 dB. Moreover, the optical responses of the same sensing fiber without decoration and modified with silver nanoparticles have also been compared. It can be observed that the output intensity of the Ag nanoparticle-modified sensor is enhanced and the sensitivity is higher. Meanwhile, the absorbance spectra are found to be more sensitive to concentration changes compared to the spectra of the peak wavelength. PMID:23519353

  18. Near-infrared fluorescence imaging of a solitary fibrous tumor of the pancreas using methylene blue.

    PubMed

    van der Vorst, Joost R; Vahrmeijer, Alexander L; Hutteman, Merlijn; Bosse, Tjalling; Smit, Vincent T H B M; van de Velde, Cornelis J H; Frangioni, John V; Bonsing, Bert A

    2012-07-27

    A 67-year-old female presented with unexplained abdominal pain. A contrast-enhanced computed tomography scan of the abdomen incidentally revealed a mass in the uncinate process of the pancreas. This mass was resected and based on histopathological findings, diagnosed as a solitary fibrous tumor (SFT) of the pancreas. A SFT is an extremely rare benign mesenchymal tumor that in 65% of cases affects the visceral pleura but can also affect extra-pleural sites. The intraoperative demarcation of pancreatic tumors, such as SFTs, can be challenging. In this report, the first clear intraoperative identification of a SFT of the pancreas in a human was shown using near-infrared fluorescence and methylene blue.

  19. Data on synthesis of methylene bisphosphonates and screening of their inhibitory activity towards HIV reverse transcriptase.

    PubMed

    Yanvarev, D V; Korovina, A N; Usanov, N N; Khomich, O A; Vepsäläinen, J; Puljula, E; Kukhanova, M K; Kochetkov, S N

    2016-09-01

    Inorganic pyrophosphate (PPi) mimetics designed on a basis of methylenediphosphonic acid backbone are promising inhibitors of two key HIV replication enzymes, IN [1] and RT [2]. Herein, we present chemical synthesis of eleven methylenebisphosphonates (BPs) with their NMR and HRMS analysis synthesized via five different ways. Also, we present data on inhibition of HIV RT catalyzed phosphorolysis and polymerization by synthesized BPs using two methods based on denaturing urea PAGE. Tests were also performed for thymidine analogue mutations reverse transcriptase (TAM RT), which was expressed and purified for that. Structure-activity relationships and inhibitory activity data of synthesized BPs are presented in "Methylene bisphosphonates as the inhibitors of HIV RT phosphorolytic activity" [2]. PMID:27547792

  20. Adsorption of methylene blue onto jute fiber carbon: kinetics and equilibrium studies.

    PubMed

    Senthilkumaar, S; Varadarajan, P R; Porkodi, K; Subbhuraam, C V

    2005-04-01

    Jute fiber obtained from the stem of a plant was used to prepare activated carbon using phosphoric acid. Feasibility of employing this jute fiber activated carbon (JFC) for the removal of Methylene blue (MB) from aqueous solution was investigated. The adsorption of MB on JFC has found to dependent on contact time, MB concentration and pH. Experimental result follows Langmuir isotherm model and the capacity was found to be 225.64 mg/g. The optimum pH for the MB removal was found to be 5-10. The kinetic data obtained at different concentrations have been analyzed using a pseudo-first-order, pseudo-second-order equation, intraparticle diffusion and Elovich equation. Among the kinetic models studied, the intraparticle diffusion was the best applicable model to describe the adsorption of MB onto JFC.

  1. Laser-induced silver nanoparticles on titanium oxide for photocatalytic degradation of methylene blue.

    PubMed

    Whang, Thou-Jen; Huang, Hsien-Yu; Hsieh, Mu-Tao; Chen, Jyun-Jen

    2009-10-29

    Silver nanoparticles doped on titanium oxide (TiO(2)) were produced by laser-liquid interaction of silver nitrate (AgNO(3)) in isopropanol. Characteristics of Ag/TiO(2) (Ag doped TiO(2)) nanoparticles produced by the methods presented in this article were investigated by XRD, TEM, SEM, EDX, and UV-Vis. From the UV-Vis measurements, the absorption of visible light of the Ag/TiO(2) photocatalysts was improved (additional absorption at longer wavelength in visible light region) obviously. The photocatalytic efficiency of Ag/TiO(2) was tested by the degradation of methylene blue (MB) in aqueous solution. A maximum of 82.3% MB degradation is achieved by 2.0 wt% Ag/TiO(2) photocatalyst under 2 h illumination with a halogen lamp.

  2. Pseudopeptide-Based Hydrogels Trapping Methylene Blue and Eosin Y.

    PubMed

    Milli, Lorenzo; Zanna, Nicola; Merlettini, Andrea; Di Giosia, Matteo; Calvaresi, Matteo; Focarete, Maria Letizia; Tomasini, Claudia

    2016-08-16

    We present herein the preparation of four different hydrogels based on the pseudopeptide gelator Fmoc-l-Phe-d-Oxd-OH (Fmoc=fluorenylmethyloxycarbonyl), either by changing the gelator concentration or adding graphene oxide (GO) to the water solution. The hydrogels have been analysed by rheological studies that demonstrated that pure hydrogels are slightly stronger compared to GO-loaded hydrogels. Then the hydrogels efficiency to trap the cationic methylene blue (MB) and anionic eosin Y (EY) dyes has been analyzed. MB is efficiently trapped by both the pure hydrogel and the GO-loaded hydrogel through π-π interactions and electrostatic interactions. In contrast, the removal of the anionic EY is achieved in less satisfactory yields, due to the unfavourable electrostatic interactions between the dye, the gelator and GO.

  3. Report: Simultaneous determination of naphazoline hydrochloride, chlorpheniramine maleate and methylene blue in their ternary mixture.

    PubMed

    Ali, Nouruddin Wageih; Hegazy, Maha Ahmad; Abdelkawy, Mohamad; Abdelfatah, Rehab Magdy

    2013-05-01

    Validated spectrophotometric and chemometric methods were developed for determination of Naphazoline Hydrochloride (NAP), Chlorpheniramine maleate (CLO) and Methylene blue (MB) in their ternary mixture. Method A was a spectrophotometric method, where NAP and MB were determined using second derivative (D²) spectrophoto metric method using the peak amplitudes at 299 nm and 337 nm for NAP and MB respectively , while CLO was determined using second derivative ratio (DD²) spectrophotometric method using the peak amplitude at 276.6 nm. Method B used the chemometric techniques; principal component regression (PCR) and partial least squares (PLS) for determination of NAP, CLO and MB using the information contained in the absorption spectra of their ternary mixture solutions. The proposed methods have been successfully applied for the analysis of NAP, CLO and MB in their pharmaceutical formulation and the obtained results were statistically compared with the reported methods.

  4. LED-activated methylene blue-loaded Pluronic-nanogold hybrids for in vitro photodynamic therapy.

    PubMed

    Simon, Timea; Boca-Farcau, Sanda; Gabudean, Ana-Maria; Baldeck, Patrice; Astilean, Simion

    2013-12-01

    In this work we introduce a new class of multifunctional photodynamic agents based on the coupling of photosensitizer molecules with noble metal nanoparticles, which can be efficiently activated under low light intensity. The favourable modification of the photophysical properties of methylene blue (MB) in MB-loaded Pluronic-nanogold hybrids (Au-PF127-MB) increases the probability of singlet oxygen generation, which in turn allows the use of a light emitting diode (LED) irradiation source instead of commonly used, more invasive lasers. In this regard, Au-PF127-MB treated human lung carcinoma cells (HTB 177) were irradiated at different light doses, using a 660 nm LED source, the results indicating a dose dependent therapeutic effect, decreasing the cell viability down to 13%. Owing to their effectiveness, biocompatibility and integrated imaging and therapeutic functionalities, Au-PF127-MB could represent an important development in the field of biophotonic applications.

  5. Detection of chemisorbed methyl and methylene groups: Surface chemistry of methyl iodide on Pt(111)

    SciTech Connect

    Zaera, F.; Hoffmann, H. )

    1991-08-08

    The thermal chemistry of methyl iodide on Pt(111) surfaces was studied by using thermal programmed desorption (TPD), X-ray photoelectron (XPS), and reflection-absorption (RAIRS) spectroscopies. Spectra obtained at low temperatures for both normal and fully deuterated methyl iodide indicate that chemisorption is molecular and that the adsorption geometry changes with coverage, starting with a tilted configuration after small doses and switching to a structure where the C-I bond is perpendicular to the surface above half-saturation. The only reaction that can be thermally activated at low coverages is a C-I bond breaking step, which is then followed by total dehydrogenation and by hydrogen desorption. At higher coverages, however, an appreciable amount of methane also desorbs, and both methyl and methylene groups form on the surface.

  6. Strong aggregation adsorption of methylene blue from water using amorphous WO3 nanosheets

    NASA Astrophysics Data System (ADS)

    Luo, Jian Yi; Cao, Zhi; Chen, Feng; Li, Li; Lin, Yu Rong; Liang, Bao Wen; Zeng, Qing Guang; Zhang, Mei; He, Xin; Li, Chen

    2013-12-01

    In this paper, authors demonstrate the high performance of the amorphous WO3 nanosheets in the removal of methylene blue (MB) from water. The saturated MB adsorbed amount by using WO3 nanosheets as an adsorbent can reach to 600 mg/g, exceeding the ones of the normal activated carbon powders. Results indicate that the aggregation of adsorbed MB molecules occurs in the porous micro-structures of the amorphous WO3 nanosheets, and a precipitation phenomenon begins to happen when the initial MB concentration reach to 20 mg/L or greater, attributed to the density increase of WO3 nanosheets after their porous micro-structures are adsorbed with enough MB molecules.

  7. Photocatalytic activity of TiO2 nanomaterials for methylene blue dye degradation

    NASA Astrophysics Data System (ADS)

    Lee, Deuk Yong; Son, Siwon; Jeon, Min-Seok; Lee, Myung-Hyun; Kim, Bae-Yeon

    2016-04-01

    TiO2 nanomaterials were prepared by a sol-gel derived electrospinning, calcination from 500°C to 650°C, and subsequent mechanical grinding to investigate the effect of calcination temperature on crystal structure, crystallinity, and photocatalytic activity of methylene blue (MB). XRD results indicated that TiO2 nanorods calcined at 500°C is composed of anatase TiO2 only. However, mixed crystals of anatase and rutile were observed for TiO2 calcined above 550°C. Higher MB degradation was found for the TiO2 nanorods calcined at 550°C probably due to the mixed crystals and larger surface area. However, the improved photocatalytic activity was achieved for TiO2 nanotube due to the synergic combinations of mixed crystals, larger specific surface area, and light trapping effect.

  8. Citric acid modified kenaf core fibres for removal of methylene blue from aqueous solution.

    PubMed

    Sajab, Mohd Shaiful; Chia, Chin Hua; Zakaria, Sarani; Jani, Saad Mohd; Ayob, Mohd Khan; Chee, Kah Leong; Khiew, Poi Sim; Chiu, Wee Siong

    2011-08-01

    Chemically modified kenaf core fibres were prepared via esterification in the presence of citric acid (CA). The adsorption kinetics and isotherm studies were carried out under different conditions to examine the adsorption efficiency of CA-treated kenaf core fibres towards methylene blue (MB). The adsorption capacity of the kenaf core fibres increased significantly after the citric acid treatment. The values of the correlation coefficients indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich isotherm. The maximum adsorption capacity of the CA-treated kenaf core fibres was found to be 131.6mg/g at 60°C. Kinetic models, pseudo-first-order, pseudo-second-order and intraparticle diffusion, were employed to describe the adsorption mechanism. The kinetic data were found to fit pseudo-second-order model equation as compared to pseudo-first-order model. The adsorption of MB onto the CA-treated kenaf core fibres was spontaneous and endothermic.

  9. Influence of activated carbon upon the photocatalytic degradation of methylene blue under UV-vis irradiation.

    PubMed

    Matos, Juan; Montaña, Ricmary; Rivero, Eliram

    2015-01-01

    Photodegradation of methylene blue (MB) was studied on TiO2 in the presence of activated carbon (AC) prepared from the sawdust of a soft wood by physical activation under CO2 flow, by pyrolysis under N2 flow, and by chemical activation with ZnCl2 and H3PO4 under N2 flow. MB photodegradation was performed under UV and UV-visible irradiation to verify the scaling-up of the present TiO2-AC binary materials. It was verified that oxygenated surface groups on carbon were intrinsically photoactive, and a synergy effect between both solids has been estimated from the first-order apparent rate constants in the photodegradation of MB. This effect enhances the photoactivity of TiO2 up to a factor of about 9 under visible irradiation, and it was associated to the surface properties of AC. PMID:24788930

  10. Microwave assisted rapid synthesis of N-methylene phosphonic chitosan via Mannich-type reaction.

    PubMed

    Dadhich, Prabhash; Das, Bodhisatwa; Dhara, Santanu

    2015-11-20

    Bio-conjugation or functional group substitutions are well-explored methods to enhance the physico-chemical and biochemical functionality of chitosan. N-Methylene phosphonic chitosan (NMPC) is one of the major substituted forms of chitosan, which has significant bioactivity and promising biomedical application. However, the reported synthesis methods of NMPC have limitations alike poor yield, higher degradation rate and most importantly long synthesis time (∼14h). In the current study, rapid synthesis of NMPC via a Mannich type reaction route using microwave irradiation has been reported. This method of NMPC synthesis offers significantly less synthesis time with competitive product yield. Synthesized NMPC was characterized via NMR, FTIR, EDS, XRD and thermal analysis. Further, viscosity average molecular weight, solubility, and conductivity of the substituted polymer were measured. Preliminary cyto-compatibility results of synthesized NMPC were promising for further exploration in biomedical applications.

  11. Molecular Orientation Analysis of Alkyl Methylene Groups from Quantitative Coherent Anti-Stokes Raman Scattering Spectroscopy.

    PubMed

    Zhang, Chi; Wang, Jie; Jasensky, Joshua; Chen, Zhan

    2015-04-16

    Quantitative data analysis in coherent anti-Stokes Raman scattering (CARS) spectroscopy is important for extracting molecular structural information. We developed a method to derive molecular tilt angle with respect to the surface normal based on quantitative CARS spectral analysis. We showed that the tilt angle of methylene alkyl chains on a surface can be directly obtained from the CH2 symmetric/asymmetric peak ratio in a CARS spectrum. The lipid alkyl chain tilt angle from a lipid monolayer was measured to be ∼0° and was verified by sum frequency generation spectroscopy, which probes the orientations of the lipid methyl end groups. The tilt angle of a silane monolayer alkyl chain was derived to be ∼35°, which agrees with the theoretical prediction. This method is submonolayer sensitive and can also be used to interpret polarization-dependent signals in CARS microscopy. It can be applied to elucidate detailed molecular structure from CARS spectroscopic and microscopic measurements.

  12. Isolation of a strain of Agrobacterium tumefaciens (Rhizobium radiobacter) utilizing methylene urea (ureaformaldehyde) as nitrogen source.

    PubMed

    Koivunen, Marja E; Morisseau, Christophe; Horwath, William R; Hammock, Bruce D

    2004-03-01

    Methylene ureas (MU) are slow-release nitrogen fertilizers degraded in soil by microbial enzymatic activity. Improved utilization of MU in agricultural production requires more knowledge about the organisms and enzymes responsible for its degradation. A Gram-negative, MU-degrading organism was isolated from a soil in Sacramento Valley, California. The bacterium was identified as Agrobacterium tumefaciens (recently also known as Rhizobium radiobacter) using both genotypic and phenotypic characterization. The pathogenic nature of the organism was confirmed by a bioassay on carrot disks. The MU-hydrolyzing enzyme (MUase) was intracellular and was induced by using MU as a sole source of nitrogen. The bacterial growth was optimized in NH4Cl, urea, or peptone, whereas the production and specific activity of MUase were maximized with either NH4Cl or urea as a nitrogen source. The result has a practical significance, demonstrating a potential to select for this plant pathogen in soils fertilized with MU.

  13. Fluorescence tissue distribution of methylene blue used for photodynamic therapy of Helicobacter Pylori

    NASA Astrophysics Data System (ADS)

    Millson, Charles E.; Buonaccorsi, Giovanni A.; MacRobert, Alexander J.; Mlkvy, Peter; Bown, Stephen G.

    1995-03-01

    Helicobacter pylori is associated with a wide range of pathologies in the upper gastrointestinal tract. Current treatments employing antibiotics are disappointing, and an endoscopic PDT might offer a better alternative. Methylene blue is a widely known histological dye and has been in use for photodynamic therapy experimentally for some years. A prospective application of MB is photosensitization of Helicobacter pylori, but little is known about its effect with light on normal mucosa of the stomach. We studied the fluorescence microscopy of the stomachs of 3 ferrets which had been sensitized by oral route with three different concentrations of MB 1 hour prior to sacrifice. MB at all doses was seen to concentrate on the surface of the mucosa and shows little deeper penetration. As Helicobacter lie on the superficial mucosa, this study suggests that oral dosing with MB should sensitize these bacteria. These findings are an important preliminary to an in vivo trial of PDT for the treatment of H pylori.

  14. Methylene blue protects astrocytes against glucose oxygen deprivation by improving cellular respiration.

    PubMed

    Roy Choudhury, Gourav; Winters, Ali; Rich, Ryan M; Ryou, Myoung-Gwi; Gryczynski, Zygmunt; Yuan, Fang; Yang, Shao-Hua; Liu, Ran

    2015-01-01

    Astrocytes outnumber neurons and serve many metabolic and trophic functions in the mammalian brain. Preserving astrocytes is critical for normal brain function as well as for protecting the brain against various insults. Our previous studies have indicated that methylene blue (MB) functions as an alternative electron carrier and enhances brain metabolism. In addition, MB has been shown to be protective against neurodegeneration and brain injury. In the current study, we investigated the protective role of MB in astrocytes. Cell viability assays showed that MB treatment significantly protected primary astrocytes from oxygen-glucose deprivation (OGD) & reoxygenation induced cell death. We also studied the effect of MB on cellular oxygen and glucose metabolism in primary astrocytes following OGD-reoxygenation injury. MB treatment significantly increased cellular oxygen consumption, glucose uptake and ATP production in primary astrocytes. In conclusion our study demonstrated that MB protects astrocytes against OGD-reoxygenation injury by improving astrocyte cellular respiration.

  15. Determination of Key Flavor Components in Methylene Chloride Extracts from Processed Grapefruit Juice.

    PubMed

    Jella; Rouseff; Goodner; Widmer

    1998-01-19

    The relative correlation of 52 aroma and 5 taste components in commercial not-from-concentrate grapefruit juices with flavor panel preference was determined. Methylene chloride extracts of juice were analyzed using GC/MS with a DB-5 column. Nonvolatiles determined included limonin and naringin by HPLC, degrees Brix, total acids, and degrees Brix/acid ratio. Juice samples were classified into low, medium, or high categories, based on average taste panel preference scores (nine-point hedonic scale). Principal component analysis demonstrated that highest quality juices were tightly clustered. Discriminant analysis indicated that 82% of the samples could be identified in the correct preference category using only myrcene, beta-caryophyllene, linalool, nootkatone, and degrees Brix. Nootkatone alone was not strongly associated with preference scores. The most preferred juices were strongly associated with low myrcene, low linalool, and intermediate levels of beta-caryophyllene. PMID:10554226

  16. Comparison effects and dielectric properties of different dose methylene-blue-doped hydrogels.

    PubMed

    Yalçın, O; Coşkun, R; Okutan, M; Öztürk, M

    2013-08-01

    The dielectric properties of methylene blue (MB)-doped hydrogels were investigated by impedance spectroscopy. The real part (ε') and the imaginary part (ε") of the complex dielectric constant and the energy loss tangent/dissipation factor (tan δ) were measured in the frequency range of 10 Hz to 100 MHz at room temperature for pH 5.5 value. Frequency variations of the resistance, the reactance, and the impedance of the samples have also been investigated. The dielectric permittivity of the MB-doped hydrogels is sensitive to ionic conduction and electrode polarization in low frequency. Furthermore, the dielectric behavior in high-frequency parts was attributed to the Brownian motion of the hydrogen bonds. The ionic conduction for MB-doped samples was prevented for Cole-Cole plots, while the Cole-Cole plots for pure sample show equivalent electrical circuit. The alternative current (ac) conductivity increases with the increasing MB concentration and the frequency.

  17. Kinetics and mechanism of removal of methylene blue by adsorption onto perlite.

    PubMed

    Doğan, Mehmet; Alkan, Mahir; Türkyilmaz, Aydin; Ozdemir, Yasemin

    2004-06-18

    The kinetics and mechanism of methylene blue adsorption on perlite have been studied. The effects of various experimental parameters, such as initial dye concentration, temperature and pH on the adsorption rate were investigated. Adsorption measurements show that the process is very fast and physical in nature. The extent of the dye removal increased with increase in the initial concentration of the dye and the initial pH and temperature of solution. Adsorption data were modelled using the first and second-order kinetic equations, mass transfer and intra-particle diffusion models. It was shown that the second-order kinetic equation could best describe the sorption kinetics. The diffusion coefficient, D, was found to increase when the initial dye concentration, pH and temperature were raised. Thermodynamic activation parameters, such as DeltaG*, DeltaS* and DeltaH*, were calculated.

  18. Calix[4]arene coated QCM sensors for detection of VOC emissions: Methylene chloride sensing studies.

    PubMed

    Temel, Farabi; Tabakci, Mustafa

    2016-06-01

    This paper describes the sensing studies of QCM sensors with coated some calixarene derivatives bearing different functional groups for some selected Volatile Organic Compounds (VOCs) such as acetone, acetonitrile, carbon tetrachloride, chloroform, methylene chloride (MC), N,N-dimethylformamide, 1,4-dioxane, ethanol, ethyl acetate, xylene, methanol, n-hexane and toluene. The initial experiments have revealed that whole the calix[4]arene modified QCM sensors exhibited strongest sensing ability to MC emissions. Thus, the detailed studies were performed for only MC emissions after the determination of relatively more effective calix-coated QCM sensors for MC emissions in aqueous media. The results demonstrated that QCM sensor coated with calix-7 bearing both amino and imidazole groups was most useful sensor for MC emissions with 54.1ppm of detection limit. Moreover, it was understood that cyclic structures, H-bonding capabilities and also good preorganization properties of calixarene derivatives played an important role in VOC sensing processes. PMID:27130112

  19. Fixed-bed adsorption study of methylene blue onto pyrolytic tire char

    NASA Astrophysics Data System (ADS)

    Makrigianni, Vassiliki; Giannakas, Aris; Papadaki, Maria; Albanis, Triantafyllos; Konstantinou, Ioannis

    2016-04-01

    In this work, the adsorption efficiency of acid treated pyrolytic tire char to cationic methylene blue (MB) dye adsorption from aqueous solutions was investigated by fixed-bed adsorption column experiments. The effects of the initial dye concentration (10 - 40 mg L-1) and feed flow rate (50 - 150 mL min -1) with a fixed bed height (15 cm) were studied in order to determine the breakthrough characteristics of the adsorption system. The Adams-Bohart, Yoon-Nelson and Thomas model were applied to the adsorption of MB onto char at different operational conditions to predict the breakthrough curves and to determine the characteristic parameters of the column. The results showed that the maximum adsorbed quantities decreased with increasing flow rate and increased with increasing initial MB concentration. Breakthrough time and exhaustion time increased with decreasing inlet dye concentration and flow rate. In contrast with Adams-Bohart model, Yoon-Nelson model followed by Thomas model were found more suitable to describe the fixed-bed adsorption of methylene blue by char. The correlation coefficient values R2 for both models at different operating conditions are higher than 0.9 and the low average relative error values provided very good fittings of experimental data at different operating conditions. Higher adsorption capacity of 3.85 mg g -1 was obtained at 15 cm of adsorbent bed height, flow rate of 100 mL min -1and initial MB concentration of 40 mg L-1. Although that activated carbons exhibited higher adsorption capacities in the literature, acid-treated pyrolytic tire char was found to be considerably efficient adsorbent for the removal of MB dye column taking into account the advantages of the simpler production process compared to activated carbons, as well as, the availability of waste tire feedstock and concurrent waste tire management.

  20. Isolation of methylene dianiline and aqueous-soluble biodegradation products from polycarbonate-polyurethanes.

    PubMed

    Tang, Y W; Labow, R S; Santerre, J P

    2003-08-01

    Polycarbonate-polyurethanes (PCNUs) have provided the medical device industry with practical alternatives to oxidation-sensitive polyether-urethanes (PEUs). To date, many studies have focused on PCNUs synthesized with 4,4'-methylene diphenyl-diisocyanate (MDI). The relative hydrolytic stability of this class of polyurethanes is actually quite surprising given the inherent hydrolytic potential of the aliphatic carbonate group. Yet, there has been little information reporting on the rationale for the material's demonstrated hydrolytic stability. Recent work has shown that PCNU materials have a strong sensitivity towards hydrolysis when changes are made to their hard segment content and/or chemistry. However, knowledge is specifically lacking in regards of the identification of cleavage sites and the specific nature of the biodegradation products. Using high-performance liquid chromatography, radiolabel tracers and mass spectrometry, the current study provides insight into the distribution of biodegradation products from the enzyme-catalyzed hydrolysis of five different PCNUs. The hydrolytic sensitivity of the materials is shown to be related to the distribution of products, which itself is a direct consequence of unique micro-structures formed within the different materials. While an MDI-based polymer was shown to be the most hydrolytically stable material, it was the only PCNU that produced its diamine analog, in this case 4,4'-methylene dianiline (MDA), as a degradation product. Given the concern over aromatic diamine toxicity, this finding is important and highlights the fact that relative biostability is a distinct issue from that of degradation product toxicity, and that both must be considered separately when assessing the impact of biodegradation on biomaterial in vivo compatibility.

  1. Perioperative Diagnosis and Treatment of Serotonin Syndrome Following Administration of Methylene Blue

    PubMed Central

    Francescangeli, James; Vaida, Sonia; Bonavia, Anthony S.

    2016-01-01

    Patient: Male, 67 Final Diagnosis: Serotonin syndrome Symptoms: Agitation • muscular spasticity, deficient muscular control • nystygmus • sweating • tachycardia Medication: Methylene Blue Clinical Procedure: Total abdominal colectomy Specialty: Anesthesiology Objective: Unusual clinical course Background: Serotonin syndrome (SS) involves serotonergic hyperactivity caused by excessive activation of 5-HT2A receptors. As the use of antidepressants increases, so does the population of patients at risk for developing this complication. The diagnosis is made based on current serotonergic medication use in conjunction with certain clinical signs. The severity of the clinical presentation may vary, especially when the complication occurs while the patient is under general anesthesia. As a result, the incidence of SS is likely underreported and treatment may be delayed, leading to life-threatening complications. Case Report: A 67-year-old, American Society of Anesthesiologist physical status 3 male with multiple medical comorbidities, including anxiety/depression and chronic neck pain, presented for an elective laparoscopic total abdominal colectomy for colonic inertia. His intraoperative course was significant for SS likely triggered by the administration of methylene blue, which only became clinically apparent during anesthetic emergence. We considered and systematically ruled out other potential causes of his clinical condition. His management was primarily supportive, using hydration and benzodiazepine administration, and resulted in full neurologic recovery. Conclusions: SS is an underdiagnosed condition with limited treatment options beyond symptom management. Thus, vigilance, early diagnosis, and cessation of offending medications are of utmost importance. Anesthesiologists managing at-risk surgical patients must have a high clinical suspicion of perioperative SS if their patients exhibit tachycardia, hypertension, and hyperthermia together with clonus

  2. Conformational analysis of oleandomycin and its 8-methylene-9-oxime derivative by NMR and molecular modelling.

    PubMed

    Novak, Predrag; Tomisić, Zrinka Banić; Tepes, Predrag; Lazarevski, Gorjana; Plavec, Janez; Turkalj, Gordana

    2005-01-01

    Conformations of the 14-membered macrolide antibiotic oleandomycin and its 8-methylene-9-oxime derivative were determined in various solvents. The experimental NMR data--coupling constants and NOE contacts--were compared with the results of molecular modelling--molecular mechanics calculations and molecular dynamics simulations. The conformational changes, on the right-hand side of the 14-membered ring, affected mostly the 3JH2,H3 values and NOE crosspeaks H3 or H4 to H11. Oleandomycin was found to be present predominantly in the C3-C5 folded-in conformations in DMSO-d6 solution, whereas in buffered D2O, acetone-d6 and CDCl3, there was a mixture of folded-in and folded-out conformational families. The predominant conformation of the 8-methylene-oleandomycin-9-oxime derivative in solution was a folded-out one although different amounts of folded-in conformation were also present depending on the solvent. Oleandrose and desosamine sugar moieties adopted the usual and expected chair conformation. The conformation around the glycosidic bonds, governing the relative orientation of sugars vs. the lactone ring, showed a certain flexibility within two conformationally close families. We believe that by combining the experimental NMR data and the molecular modelling techniques, as reported in this paper, we have made significant progress in understanding the conformational behaviour and properties of macrolides. Our belief is based on our own current studies on oleandomycins as well as on the previously reported results and best practices concerning other macrolides. A rational for macrolide conformational studies and advances in methodology has been suggested accordingly. PMID:15602597

  3. Computed Tomography Guided Percutaneous Injection of a Mixture of Lipiodol and Methylene Blue in Rabbit Lungs: Evaluation of Localization Ability for Video-Assisted Thoracoscopic Surgery

    PubMed Central

    Jin, Kwang Nam; Kim, Tae Jung; Song, Yong Sub; Kim, Dong Il

    2014-01-01

    Preoperative localization is necessary prior to video assisted thoracoscopic surgery for the detection of small or deeply located lung nodules. We compared the localization ability of a mixture of lipiodol and methylene blue (MLM) (0.6 mL, 1:5) to methylene blue (0.5 mL) in rabbit lungs. CT-guided percutaneous injections were performed in 21 subjects with MLM and methylene blue. We measured the extent of staining on freshly excised lung and evaluated the subjective localization ability with 4 point scales at 6 and 24 hr after injections. For MLM, radio-opacity was evaluated on the fluoroscopy. We considered score 2 (acceptable) or 3 (excellent) as appropriate for localization. The staining extent of MLM was significantly smaller than methylene blue (0.6 vs 1.0 cm, P<0.001). MLM showed superior staining ability over methylene blue (2.8 vs 2.2, P=0.010). Excellent staining was achieved in 17 subjects (81%) with MLM and 8 (38%) with methylene blue (P=0.011). An acceptable or excellent radio-opacity of MLM was found in 13 subjects (62%). An appropriate localization rate of MLM was 100% with the use of the directly visible ability and radio-opacity of MLM. MLM provides a superior pulmonary localization ability over methylene blue. PMID:24431917

  4. Color measurement of methylene blue dye/clay mixtures and its application using economical methods

    NASA Astrophysics Data System (ADS)

    Milosevic, Maja; Kaludjerovic, Lazar; Logar, Mihovil

    2016-04-01

    Identifying the clay mineral components of clay materials by staining tests is rapid and simple, but their applicability is restricted because of the mutual interference of the common components of clay materials and difficulties in color determination. The change of color with concentration of the dye is related to the use of colorants as a field test for identifying clay minerals and has been improved over the years to assure the accuracy of the tests (Faust G. T., 1940). The problem of measurement and standardization of color may be solved by combination of colors observed in staining tests with prepared charts of color chips available in the Munsell Book of Color, published by Munsell Color Co. Under a particular set of illumination conditions, a human eye can achieve an approximate match between the color of the dyed clay sample and that of a standard color chip, even though they do have different spectral reflectance characteristics. Experiments were carried out with diffuse reflectance spectroscopy on selected clay samples (three montmorillonite, three kaolinite and one mix-layer clay samples) saturated with different concentration of methylene blue dye solution. Dominant wavelength and purity of the color was obtained on oriented dry samples and calculated by use of the I. C. I. (x, y) - diagram in the region of 400-700 nm (reflectance spectra) without MB and after saturation with different concentrations of MB solutions. Samples were carefully photographed in the natural light environment and processed with user friendly and easily accessible applications (Adobe color CC and ColorHexa encyclopedia) available for android phones or tablets. Obtained colors were compared with Munsell standard color chips, RGB and Hexa color standards. Changes in the color of clay samples in their interaction with different concentration of the applied dye together with application of economical methods can still be used as a rapid fieldwork test. Different types of clay

  5. The interactions of azure B, a metabolite of methylene blue, with acetylcholinesterase and butyrylcholinesterase

    SciTech Connect

    Petzer, Anél; Harvey, Brian H.; Petzer, Jacobus P.

    2014-02-01

    Methylene blue (MB) is reported to possess diverse pharmacological actions and is attracting increasing attention for the treatment of neurodegenerative disorders such as Alzheimer's disease. Among the pharmacological actions of MB, is the significant inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). These activities may, at least in part, underlie MB's beneficial effects in Alzheimer's disease. MB is metabolized to yield N-demethylated products of which azure B, the monodemethyl metabolite, is the predominant species. Azure B has been shown to be pharmacologically active and also possesses a variety of biological actions. Azure B therefore may contribute to the pharmacological profile of MB. Based on these considerations, the present study investigates the possibility that azure B may, similar to MB, act as an inhibitor of human AChE and BuChE. The results document that azure B inhibits AChE and BuChE with IC{sub 50} values of 0.486 μM and 1.99 μM, respectively. The results further show that azure B inhibits AChE and BuChE reversibly, and that the modes of inhibition are most likely competitive. Although the AChE and BuChE inhibitory activities of azure B are twofold and fivefold, respectively, less potent than those recorded for MB [IC{sub 50}(AChE) = 0.214 μM; IC{sub 50}(BuChE) = 0.389 μM] under identical conditions, azure B may be a contributor to MB's in vivo activation of the cholinergic system and beneficial effects in Alzheimer's disease. - Highlights: • Methylene blue (MB) is a known inhibitor of AChE and BuChE. • Azure B, the major metabolite of MB, also is an inhibitor of AChE and BuChE. • Azure B may be a contributor to MB's in vivo activation of the cholinergic system. • Azure B may contribute to MB's potential in Alzheimer's disease therapy.

  6. Use of methylene blue as a simulant for the physical properties of cocaine HCl and heroin HCl

    NASA Astrophysics Data System (ADS)

    Patrick, Julie C.; Orzechowska, Grazyna E.; Poziomek, Edward J.

    1997-02-01

    Technological challenges in the development and testing of illicit narcotics include assuring safety of researchers and operations personnel from drug exposure, assessing the efficiency of sampling and sample handling, checking for artifacts introduced by field procedures, and maintaining quality control/quality assurance. The dye methylene blue was chosen as a simulant for cocaine HCl and heroin HCl. The similarities include the presence of fused ring systems, molecular weights over 300 g/mol, and melting points between 200 and 300 degrees C. A significant difference is that methylene blue has a much lower solubility in water than cocaine HCl and heroin HCl. Experiments have been conducted to successfully increase the solubility of the simulant to match those of cocaine HCl and heroin HCl by adding solidum methyl sulfate.

  7. Methylene blue adsorption onto swede rape straw (Brassica napus L.) modified by tartaric acid: equilibrium, kinetic and adsorption mechanisms.

    PubMed

    Feng, Yanfang; Zhou, Hui; Liu, Guohua; Qiao, Jun; Wang, Jinhua; Lu, Haiying; Yang, Linzhang; Wu, Yonghong

    2012-12-01

    The aim of this study was to develop a promising and competitive bioadsorbent with the abundant of source, low price and environmentally friendly characters to remove cationic dye from wastewater. The swede rape straw (Brassica napus L.) modified by tartaric acid (SRSTA) was prepared, characterized and used to remove methylene blue (MB) from aqueous solution at varied operational conditions (including MB initial concentrations, adsorbent dose, etc.). Results demonstrated that the equilibrium data was well fitted by Langmuir isotherm model. The maximum MB adsorption capacity of SRSTA was 246.4 mg g(-1), which was comparable to the results of some previous studied activated carbons. The higher dye adsorption capacity could be attributed to the presence of more functional groups such as carboxyl group on the surface of SRSTA. The adsorption mechanism was also discussed. The results indicate that SRSTA is a promising and valuable absorbent to remove methylene blue from wastewater.

  8. Adsorption of methylene blue on raw and MTZ/imogolite hybrid surfaces: effect of concentration and calorimetric investigation.

    PubMed

    Guerra, Denis L; Batista, Adriano C; Viana, Rúbia R; Airoldi, Claudio

    2010-11-15

    The synthetic imogolite sample was used for organofunctionalization process with 2-mercaptothiazoline (MTZ). The compound 2-mercaptothiazoline was anchored onto imogolite surface by heterogeneous route. Due to the increment of basic centers attached to the pendant chains the dye adsorption capability of the final chelating material, was found to be higher than is precursor. The ability of these materials to remove methylene blue from aqueous solution was followed by a series of adsorption isotherms at room temperature and pH 4.0. The maximum number of moles adsorbed was determined to be 40.32×10(-2) and 65.13×10(-2) mmol g(-1) for IMO and IMO(MTZ), respectively. The energetic effects caused by dye cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such methylene blue-nitrogen and sulfur interactions.

  9. One-pot preparation of superparamagnetic attapulgite/Fe3O4/polydopamine nanocomposites for adsorption of methylene blue

    NASA Astrophysics Data System (ADS)

    Mu, Bin; Kang, Yuru; Zheng, Maosong; Wang, Aiqin

    2016-05-01

    Superparamagnetic attapulgite/Fe3O4/polydopamine nanocomposites have been facilely prepared by a one-pot process without the nitrogen protection, in which Fe(III) was served as both of the oxidant for dopamine and the precursor of Fe3O4 in the presence of attapulgite. The introduction of attapulgite can effectively induce the uniform encapsulation of polydopamine and Fe3O4 nanoparticles on the surface of attapulgite, preventing from the formation of the free aggregates of Fe3O4 nanoparticles. The as-prepared APT/Fe3O4/PANI nanocomposites can be used as an adsorbent for the removal of methylene blue, and the adsorption ratio toward 100 ppm of methylene blue could reach 95.8%.

  10. Simultaneous adsorption of methyl red and methylene blue onto biochar and an equilibrium modeling at high concentration.

    PubMed

    Ding, Guanyu; Wang, Buyun; Chen, Lingyu; Zhao, Shuangjiao

    2016-11-01

    Methyl red, methylene blue and biochar were used to investigate simultaneous adsorption of dyes onto low-cost adsorbent at different concentrations combinations. Langmuir mixed model could describe the adsorption well at low concentrations. However, it could not describe the adsorption anymore when concentrations of methyl red and methylene blue were higher than 255 and 300 mg L(-1) respectively with 0.5 g L(-1) biochar loading. A new model on the interaction among adsorbed adsorbates at equilibrium was developed. It could describe the adsorption at high concentrations well. According to the experimental results, interaction among dyes molecules would replace the competition onto adsorbent to be the main factor influencing adsorption when amount of adsorbed adsorbates were higher than those required to form a monolayer on all the adsorbing sites of adsorbent. The model was further verified by adsorption with other solute such as glucose or NaCl in solution.

  11. Studies on the ion-association of methylene blue and salicylic acid in neat and mixed binary solvents

    NASA Astrophysics Data System (ADS)

    Basu, Soumen; Ghosh, Sujit Kumar; Kundu, Subrata; Nath, Sudip; Panigrahi, Sudipa; Praharaj, Snigdhamayee; Pal, Tarasankar

    2005-05-01

    Thiazine dye, methylene blue forms 1:1 ion-associate with salicylic acid in aqueous phase and the ion-associate can be extracted in a series of non-polar non-coordinating solvent systems. The influence of different parameters on the process of ion-association has been studied. The suitability of a number of phenolic precursors for the formation of ion-associate with methylene blue has been tested. Charge-transfer absorption band of the dye molecules in relation to ion-pair has been followed in a sequence of neat and mixed binary solvents and the dependence of the absorption maxima has been found to correlate well with the solvent polarity.

  12. Rapid inactivation of HIV-1 in single donor preparations of human fresh frozen plasma by methylene blue/light treatment.

    PubMed

    Lambrecht, B; Norley, S G; Kurth, R; Mohr, H

    1994-09-01

    Human fresh frozen plasma (FFP) was spiked with highly titered HIV-1 and illuminated with visible light in the presence of 1 microM of the photoactive dye methylene blue (MB). As shown by titration on MT-4 cells, the infectivity of the virus containing plasma was rapidly lost during illumination: after 5 min the infective titer was reduced by 4.3 and after 10 min by at least 6.32 log10, i.e. it was below the detection limit of the assay applied. Methylene blue without illumination and illumination alone had only a marginal effect on HIV-1 infectivity. Thus our data indicate that the MB/light treatment of FFP is an effective method to eliminate the risk of HIV-1 infection through use of the product. This is especially important for those cases in which the plasma is collected during the 'window period' between infection of the donor and the subsequent seroconversion.

  13. Sonocatalytic Methylene Blue in The Presence of Fe3O4-CuO-TiO2 Nanocomposites Heterostructure

    NASA Astrophysics Data System (ADS)

    Fauzian, Malleo; Jalaludin, Shofianina; Taufik, Ardiansyah; Saleh, Rosari

    2016-04-01

    In this work, the emphasis was mainly placed on investigating the sonocatalytic activity of Fe3O4-CuO-TiO2 nanocomposites heterostructure. The prepared samples were characterized by X-ray diffraction (XRD), Vibrating Sample Magnetometer (VSM), Brunauer-Emmett-Teller (BET) Surface Area Analysis. Methylene blue dye was selected to examine the sonocatalytic activity of Fe3O4-CuO-TiO2 nanocomposites heterostructure. The degradation reaction processes were monitored by UV-vis spectrophotometer. The influence on the activity of the Fe3O4-CuO-TiO2 nanocomposites heterostructure such as TiO2 loading was studied. The sonocatalyst Fe3O4-CuO-TiO2 with molar ratio of 1:1:5 showed the highest sonocatalytic activity. At last, the experiment also indicated that holes are the main reactive species in the photodegradation mechanism in methylene blue.

  14. Bipolar pulsed electrical discharge for decomposition of methylene blue in aqueous TiO2 nanoparticle dispersions.

    PubMed

    Kim, Byung Hoon; Kim, Sun-Jae; Chung, Minchul; Ahn, Ho-Geun; Lee, Heon; Park, Sung Hoon; Jung, Sang-Chul

    2013-03-01

    The objective of this paper is to investigate the decomposition process of organic pollutants by liquid phase plasma. A bipolar pulsed power supply was used to generate discharges in the aqueous TiO2 nanoparticle dispersions. The applied voltage, pulse width, and frequency were 250 V, 5 micros, and 30 kHz, respectively. Properties of generated plasma were investigated by electrical and optical emission spectroscopy methods. The comparison of properties of the discharge operated with and without oxygen gas bubbling is shown. The results of electrical-discharge degradation of methylene blue showed that the decomposition rate increased with the TiO2 particle dosages. Addition of oxygen gas bubbles also increased the degradation rate of methylene blue.

  15. Tubular structured hierarchical mesoporous titania material derived from natural cellulosic substances and application as photocatalyst for degradation of methylene blue

    SciTech Connect

    Huang, Haiqing; Liu, Xiaoyan; Huang, Jianguo

    2011-11-15

    Graphical abstract: Bio-inspired, tubular structured hierarchical mesoporous titania material with high photocatalytic activity under UV light was fabricated employing natural cellulosic substance (cotton) as hard template and cetyltrimethylammonium bromide (CTAB) surfactant as soft template using a one-pot sol-gel method. Highlights: {yields} Tubular structured mesoporous titania material was fabricated by sol-gel method. {yields} The titania material faithfully recorded the hierarchical structure of the template substrate (cotton). {yields} The titania material exhibited high photocatalytic activity in decomposition of methylene blue. -- Abstract: Bio-inspired, tubular structured hierarchical mesoporous titania material was designed and fabricated employing natural cellulosic substance (cotton) as hard template and cetyltrimethylammonium bromide (CTAB) surfactant as soft template by one-pot sol-gel method. The tubular structured hierarchical mesoporous titania material processes large specific surface area (40.23 m{sup 2}/g) and shows high photocatalytic activity in the photodegradation of methylene blue under UV light irradiation.

  16. Simultaneous adsorption of methyl red and methylene blue onto biochar and an equilibrium modeling at high concentration.

    PubMed

    Ding, Guanyu; Wang, Buyun; Chen, Lingyu; Zhao, Shuangjiao

    2016-11-01

    Methyl red, methylene blue and biochar were used to investigate simultaneous adsorption of dyes onto low-cost adsorbent at different concentrations combinations. Langmuir mixed model could describe the adsorption well at low concentrations. However, it could not describe the adsorption anymore when concentrations of methyl red and methylene blue were higher than 255 and 300 mg L(-1) respectively with 0.5 g L(-1) biochar loading. A new model on the interaction among adsorbed adsorbates at equilibrium was developed. It could describe the adsorption at high concentrations well. According to the experimental results, interaction among dyes molecules would replace the competition onto adsorbent to be the main factor influencing adsorption when amount of adsorbed adsorbates were higher than those required to form a monolayer on all the adsorbing sites of adsorbent. The model was further verified by adsorption with other solute such as glucose or NaCl in solution. PMID:27543677

  17. Methylene blue, midodrine, and pseudoephedrine: a review of alternative agents for refractory hypotension in the intensive care unit.

    PubMed

    Van Berkel, Megan A; Fuller, Laura A; Alexandrov, Anne W; Jones, G Morgan

    2015-01-01

    Hypotensive episodes are common among patients in the intensive care unit and can lead to multiorgan failure if uncontrolled. Fluid administration and continuous infusion of vasoactive agents are frequently used for management of hypotension; however, both therapies may be associated with adverse effects including pulmonary edema and tissue necrosis. In addition, availability of these first-line agents has been impacted by the increasing occurrence of drug shortages. Methylene blue, pseudoephedrine, and midodrine have been considered potential alternatives to standard therapy. These agents may not only be used when first-line agents are unavailable due to shortages, but they may also aid in reducing the cumulative dose of other vasoactive agents used. The purpose of this review was to discuss strategies for the safe and effective use of methylene blue, pseudoephedrine, and midodrine for the treatment of hypotension in the critically ill.

  18. Synthesis of Isoxazoline/Cyclic Nitrone-Featured Methylenes Using Unsaturated Ketoximes: A Dual Role of TEMPO.

    PubMed

    Chen, Fei; Yang, Xiu-Long; Wu, Zhi-Wei; Han, Bing

    2016-04-01

    A novel, metal-free, and regioselective approach for the synthesis of isoxazoline/cyclic nitrone-featured methylenes has been developed by the reaction of readily accessible β,γ- and γ,δ-unsaturated ketoximes with TEMPO via tandem iminoxyl radical-promoted cyclization/TEMPO-mediated Cope-like elimination, respectively. This protocol utilizes commercially available TEMPO as the iminoxyl radical initiator as well as the β-hydrogen acceptor in the Cope-like elimination.

  19. Methylene blue injection into the rectal artery as a simple method to improve lymph node harvest in rectal cancer.

    PubMed

    Märkl, Bruno; Kerwel, Therese G; Wagner, Theodor; Anthuber, Matthias; Arnholdt, Hans M

    2007-07-01

    Adequate lymph node assessment in colorectal cancer is crucial for prognosis estimation and further therapy stratification. However, there is still an ongoing debate on required minimum lymph node numbers and the necessity of advanced techniques such as immunohistochemistry or PCR. It has been proven in several studies that lymph node harvest is often inadequate under routine analysis. Lymph nodes smaller than 5 mm are especially concerning as they can carry the majority of metastases. These small, but affected lymph nodes may escape detection in routine analysis. Therefore, fat-clearing protocols and sentinel techniques have been developed to improve accuracy of lymph node staging. We describe a novel and simple method of ex vivo methylene blue injection into the superior rectal artery of rectal cancer specimens, which highlights lymph nodes and makes them easy to detect during manual dissection. Initially, this method was developed for proving accuracy of total mesorectal excision. We performed a retrospective study comparing lymph node recovery of 12 methylene blue stained and an equal number of unstained cases. Lymph node recovery differed significantly with average lymph node numbers of 27+/-7 and 14+/-4 (P<0.001) for the methylene blue and the unstained group, respectively. The largest difference was found in size groups between 1 and 4 mm causing a shift in size distribution toward smaller nodes. Metastases were confirmed in 21 and 19 lymph nodes occurring in five and four cases, respectively. Hence, we conclude that methylene blue injection technique improves accuracy of lymph node staging by heightening the lymph node harvest in rectal resections. In our experience, it is a very simple time and cost effective method that can be easily established under routine circumstances.

  20. Comparative study of polymer containing beta-cyclodextrin and -COOH for adsorption toward aniline, 1-naphthylamine and methylene blue.

    PubMed

    Zhao, Dong; Zhao, Liang; Zhu, Cheng-Shen; Shen, Xiangyu; Zhang, Xiaozhuan; Sha, Baofeng

    2009-11-15

    Three different polymers P1, P2 and P3 (P1 containing both beta-CD and -COOH, P2 containing beta-CD and P3 containing -COOH) were synthesized and applied to adsorption toward aniline, 1-naphthylamine and methylene blue. The concentrations (C) before and after adsorption were determined and the adsorption capacities (q) of P1, P2 and P3 were calculated. The maximum adsorption capacities (q(max)) toward aniline: q(max) (P1)=104 micromol g(-1), q(max) (P2)=14.9 micromol g(-1) and q(max) (P3)=53.1 micromol g(-1); toward 1-naphthylamine: q(max) (P1)=184 micromol g(-1), q(max) (P2)=53.8 micromol g(-1) and q(max) (P3)=125 micromol g(-1); toward methylene blue: q(max) (P1)=200 micromol g(-1), q(max) (P2)=12.7 micromol g(-1) and q(max) (P3)=215 micromol g(-1). P1 exhibited remarkable adsorption toward all the three adsorbates. P2 was almost equal to P1 in adsorption toward methylene blue, but was less efficient than P1 in adsorption toward aniline and 1-naphthylamine. P3 also exhibited considerable adsorption toward aniline and 1-naphthylamine, but was inefficient toward methylene blue. P1 was obtained from nontoxic materials and through environment friendly procedures, so it was potentially an efficient and green adsorbent for water purification.

  1. Bile ductular damage induced by methylene dianiline inhibits oval cell activation.

    PubMed Central

    Petersen, B. E.; Zajac, V. F.; Michalopoulos, G. K.

    1997-01-01

    Administration of 2-acetylaminofluorene (2-AAF) given before a two-thirds partial hepatectomy (PHx), results in suppression of hepatocyte proliferation and stimulation of oval cell proliferation. Our objective in this study was to examine the oval cell response and associated alpha-fetoprotein (AFP) gene expression by combining 2-AAF with selective hepatic damage caused by either carbon tetrachloride (CCl4) exposure or by PHx. We also examined oval cell response with the above two protocols (2-AAF/CCl4 and 2-AAF/PHx) as affected by previous bile ductular damage caused by 4,4'-methylene dianiline (4,4'-diaminodiphenylmethane, DAPM) exposure. DAPM is an aromatic diamine, known to cause bile ductular damage in both humans and animals. Using the protocols of 2-AAF/ CCl4 and 2-AAF/PHx, when DAPM was given 24 hours before the hepatic injury, no oval cell proliferation was seen (histological) and AFP expression was not detected by Northern blot analysis. These results provide direct evidence that oval cells are closely associated with the biliary epithelial cells and supports the theory that hepatic oval cells may originate from cells derived from either intraportal or periportal ductules. Images Figure 1 Figure 2 Figure 3 PMID:9327722

  2. Study on the interaction of methylene blue with cyclodextrin derivatives by absorption and fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Guomei; Shuang, Shaomin; Dong, Chuan; Pan, Jinghao

    2003-11-01

    The ability of β-cyclodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and carboxymethyl-β-cyclodextrin (CM-β-CD) to break the aggregate of the methylene blue (MB) and to form 1:1 inclusion complexes has been studied by absorption and fluorescence spectroscopy. Experimental conditions including concentrations of various cyclodextrins (β-CD, HP-β-CD and CM-β-CD) and media acidity were investigated for the inclusion formation in detail. The formation constants are calculated by using steady-state fluorimetry, from which the inclusion capacity of different cyclodextrins (CDs) is compared. The results suggest that the charged β-cyclodextrin (CM-β-CD) is more suitable for inclusion of the cationic dye MB than the neutral β-cyclodextrins (β-CD, HP-β-CD) at pH>5. A mechanism is proposed which is consistent with the stronger binding of MB with CM-β-CD compared with the other CDs at pH>5.

  3. Novel silicone-based polymer containing active methylene designed for the removal of indoor formaldehyde.

    PubMed

    Niu, Song; Yan, Hongxia

    2015-04-28

    Indoor air pollution is caused inevitably due to complicated home decoration, in which formaldehyde is one of the most typical pollutants. It will be a convenient, economical and effective strategy to remove indoor formaldehyde if imparting a feature of formaldehyde removal to decorative coatings. We have successfully explored a novel silicone-based polymer containing active methylene used as a formaldehyde absorbent in coatings via a straightforward transesterification process using inexpensive and easily available chemicals. The polymer has been characterized by (13)C NMR, FTIR, GC and GPC. Formaldehyde removal capacity of the coating films containing different contents of the polymer has been investigated. The results indicated that coatings incorporating 4wt% of the polymer could make the coating films exhibit significant improvement on formaldehyde removal including purificatory performance (>85%) and durability of purificatory effect (>60%), compared to those consisting of absorbents without any silicon, and improve yellowing resistance performance, while other properties, such as gloss, adhesion, pencil hardness, flexibility and impact resistance, were kept almost unaffected. The chemical absorption process of the silicone-based polymer filled in interior decorative coatings is demonstrated as a promising technology to purify indoor formaldehyde and thus can reduce the harm to individuals.

  4. Enhanced photocatalytic activity of TiO2-C hybrid aerogels for methylene blue degradation

    PubMed Central

    Shao, Xia; Lu, Wencong; Zhang, Rui; Pan, Feng

    2013-01-01

    Carbon-based TiO2 composites have many advantages as photocatalysts. However, they suffer from low light efficiency due to the low contrast of TiO2 with carbon. We synthesized a novel type of anatase-type TiO2-C hybrid aerogel by a one-pot sol-gel method, which shows a photocatalytic activity for methylene degradation up to 4.23 times that of P25, a commercial photocatalyst from Degussa Inc. The hybrid aerogels are prepared from TiCl4 and resorcinol–furfural, and have a tunable macropore size from 167 to 996 nm. They are formed of submicrometer particles that consist of interwoven anatase and carbon nanoparticles. The anatase nanoparticles have a size of 8–9 nm and a tunable oxygen vacancy from 7.2 to 18.0%. The extremely high activity is ascribed to the large light absorption caused by macropore scattering and oxygen vacancies in the anatase. These findings may open up a new avenue and stimulate further research to improve photocatalytic performance. PMID:24145581

  5. A comparison of two sampling methods for the detection of airborne methylene bisphenyl diisocyanate.

    PubMed

    Schaeffer, Joshua W; Sargent, Layne Marie; Sandfort, Delvin R; Brazile, William J

    2013-01-01

    The purpose of this study was to determine if there was a significant difference between two readily available sampling methodologies for airborne methylene bisphenyl diisocyanate (MDI), which is an essential precursor in the spray-on truck bed lining industry. Seventy-two personal airborne samples of MDI were collected and analyzed from nine spray-on truck bed liner businesses in northern Colorado. Wide ranges of exposure concentrations were encountered during the spray-on application, including concentrations that exceeded the OSHA permissible exposure limit. The highest airborne MDI concentration measured was 690 ppb. A statistically significant difference between field-desorbed and laboratory-desorbed methods was determined. The field-desorbed sampling methodology yielded consistently higher MDI concentrations than the laboratory-desorbed sampling methodology, which suggests that immediate desorption minimizes isocyanate loss and potential underestimations. Results from the analysis of variance also indicated that different facility factors and environmental conditions within each company, such as the use of ventilation or humidity level, affected the MDI concentrations, indicating the potential for better mitigation of exposures using the hierarchy of controls.

  6. Immunochemical detection of the occupational allergen, methylene diphenyl diisocyanate (MDI), in situ.

    PubMed

    Wisnewski, Adam V; Liu, Jian

    2016-02-01

    Diisocyanate chemicals essential to polyurethane production are a well-recognized cause of occupational asthma. The pathogenesis of diisocyanate-induced asthma, including the pathways by which the chemical is taken up and its distribution in exposed tissue, especially the lung, remains unclear. We developed an antiserum with specificity for methylene diphenyl diisocyanate (MDI) the most abundantly produced and utilized diisocyanate world-wide, and established its ability to detect MDI in situ. Polyclonal MDI-specific IgG was induced by immunizing rabbits with MDI-conjugated to keyhole limpet hemocyanin (KLH) emulsified in complete Freund's adjuvant, followed by two booster injections with incomplete Freund's adjuvant. The antiserum contains IgG that recognize a variety of different MDI conjugated proteins, but not unconjugated or mock exposed proteins by dot blot analysis. The antiserum further demonstrates specificity for proteins conjugated with MDI, but not other commonly used diisocyanates. Immunochemical studies with cytospun airway cells and formalin-fixed paraffin embedded lung tissue sections from mice intranasally exposed to MDI (as reversibly reactive glutathione conjugates, e.g. GSH-MDI) demonstrated the antiserum's ability to detect MDI in tissue samples. The data demonstrate penetration of MDI into the lower airways, localized deposition in the epithelial region surrounding airways, and uptake by alveolar macrophages. The new immunochemical reagent should be useful for further studies delineating the uptake and tissue distribution of MDI, especially as it relates to adverse health effects from exposure.

  7. Molecular determinants of humoral immune specificity for the occupational allergen, methylene diphenyl diisocyanate.

    PubMed

    Wisnewski, Adam V; Liu, Jian

    2013-06-01

    Methylene diphenyl diisocyanate (MDI), a low molecular weight chemical important for producing polyurethane foam, coatings, and elastomers is a major cause of occupational asthma, however, mechanisms of disease pathogenesis remain poorly understood. This study characterizes the rearranged germline and hypervariable region cDNA of new anti-MDI secreting hybridomas derived from mice immunized with MDI-conjugated to autologous serum proteins. Six IgG1 secreting clones were identified in initial screening ELISAs, based on differential binding to MDI conjugated human albumin vs. mock exposed albumin. The mAbs secreted by the hybridomas also recognized MDI conjugated to other model proteins (e.g. ovalbumin, transferrin), but did not bind unconjugated proteins, or protein conjugates prepared with other isocyanates (e.g. TDI, HDI). The mAbs displayed MDI-dose dependent binding in ELISA and Western blot, and exhibited varying degrees of cross-competition, suggesting differences in epitope specificity. The cDNA encoding the monoclonal antibodies reveal clonal differences in the CDR3 regions, germline gene usage, and patterns of somatic hypermutation related to epitope specificity. Together, the data provide new insight into the molecular determinants of humoral MDI specificity, and characterize anti-MDI IgG1 mAbs that may be developed into useful diagnostic reagents.

  8. Photocatalytic Degradation of Methylene Blue under UV Light Irradiation on Prepared Carbonaceous TiO2

    PubMed Central

    Che Ramli, Zatil Amali; Asim, Nilofar; Isahak, Wan N. R. W.; Emdadi, Zeynab; Ahmad-Ludin, Norasikin; Yarmo, M. Ambar; Sopian, K.

    2014-01-01

    This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC), TiO2/carbon (C), and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC) was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TG-DTA), Brunauer-Emmet-Teller (BET), and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2 (179 > 134 > 54 > 9 m2 g−1). The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples. PMID:25013855

  9. Heterogeneous photodegradation of methylene blue with iron and tea or coffee polyphenols in aqueous solutions.

    PubMed

    Morikawa, Claudio Kendi; Shinohara, Makoto

    2016-01-01

    Recently, we developed two new Fenton catalysts using iron (Fe) and spent tea leaves or coffee grounds as raw material. In this study, Fe-to-tea or Fe-to-coffee polyphenol complexes were successfully tested as heterogeneous photo-Fenton catalysts. The photodegradation efficiency of methylene blue solutions with Fe-to-polyphenol complexes was higher than that of homogeneous iron salts in the photo-Fenton process. Furthermore, the tested Fe-to-polyphenol complexes could be reused by simply adding H2O2 to the solutions. After three sequential additions of H2O2, the conventional catalysts FeCl2·4H2O and FeCl3 removed only 16.6% and 53.6% of the dye, while the catalysts made using spent coffee grounds and tea leaves removed 94.4% and 96.0% of the dye, respectively. These results showed that the complexes formed between Fe and chlorogenic acid, caffeic acid, gallic acid and catechin, which are the main polyphenols in tea and coffee, can be used to improve the photo-Fenton process.

  10. The binding properties of photosensitizer methylene blue to herring sperm DNA: a spectroscopic study.

    PubMed

    Zhang, Lei Z; Tang, Guo-Qing

    2004-05-27

    Methylene blue (MB) is a phenothiazinium photosensitizer with promising applications in the photodynamic therapy (PDT) for anticancer treatment. The binding properties of MB to herring sperm DNA have been investigated by the measurements of absorption spectra, quenching experiments and the elucidation of the photobleaching processes. Remarkable hypochromic and bathochromic effects of MB in the presence of increasing amounts of DNA have been observed in the absorption spectra. The quenching of MB by the DNA bases obeys the Stern-Volmer equation and ferrocyanide quenching of MB in the absence and presence of DNA is also measured as extended experiments. Results from the above spectral measurements are all consistent with the intercalative binding mode of MB to DNA with the Kb value of 1.89 x 10(4) M(-1). The photobleaching processes of MB and its DNA complex have also been studies, which indicate that the photobleaching of MB and its DNA complex proceeds with different mechanisms and the reactive oxygen species are responsible for the self-sensitized photooxidation of MB. PMID:15157907

  11. Activated carbon coated palygorskite as adsorbent by activation and its adsorption for methylene blue.

    PubMed

    Zhang, Xianlong; Cheng, Liping; Wu, Xueping; Tang, Yingzhao; Wu, Yucheng

    2015-07-01

    An activation process for developing the surface and porous structure of palygorskite/carbon (PG/C) nanocomposite using ZnCl2 as activating agent was investigated. The obtained activated PG/C was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (SEM), and Brunauer-Emmett-Teller analysis (BET) techniques. The effects of activation conditions were examined, including activation temperature and impregnation ratio. With increased temperature and impregnation ratio, the collapse of the palygorskite crystal structure was found to accelerate and the carbon coated on the surface underwent further carbonization. XRD and SEM data confirmed that the palygorskite structure was destroyed and the carbon structure was developed during activation. The presence of the characteristic absorption peaks of CC and C-H vibrations in the FTIR spectra suggested the occurrence of aromatization. The BET surface area improved by more than 11-fold (1201 m2/g for activated PG/C vs. 106 m2/g for PG/C) after activation, and the material appeared to be mainly microporous. The maximum adsorption capacity of methylene blue onto the activated PG/C reached 351 mg/g. The activated PG/C demonstrated better compressive strength than activated carbon without palygorskite clay. PMID:26141882

  12. The use of methylene blue in abdominal aortic surgery: a case report.

    PubMed

    Piraccini, E; Agnoletti, V; Corso, R; Maitan, S; Gambale, G

    2010-01-01

    The open abdominal aortic surgery includes a well-known phase in which arterial blood flow is stopped by occluding clamps, resulting in peculiar physiologic changes usually superimposed on advanced pathologic conditions. An anesthetic plan should aim at providing hemodynamic stability and preserving organ function. Clamp removal leads to an acute fall in blood pressure following a decrease in systemic vascular resistance, caused by reactive hyperemia due to opening of the previously minimally perfused vascular beds. Several different mediators, including the nitrous oxide (NO) pathway, have been thought to be responsible for this hemodynamic effect. The massive production of NO by the inducible isoform of NO synthase could be partially responsible for the profound vasodilatation and myocardial dysfunction. The dye methylene blue (MB) has been used as to prevent vasodilatation in other clinical situations like sepsis, cardiopulmonary bypass and liver transplantation. We describe its use in a patient with poor hemodynamic status, who was submitted to aortic aneurism repair with infrarenal cross clamp. The intervention was also associated with a severe bleeding. In this case MB allowed us to control hypotension with relatively low doses of vasopressors. PMID:23440623

  13. Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars.

    PubMed

    Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong

    2016-01-01

    Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB. PMID:27144922

  14. Comparative evaluation of methylene blue and demeclocycline for enhancing optical contrast of gliomas in optical images.

    PubMed

    Wirth, Dennis; Snuderl, Matija; Curry, William; Yaroslavsky, Anna

    2014-09-01

    Contrast agents have shown to be useful in the detection of cancers. The goal of this study was to compare enhancement of brain cancer contrast using reflectance and fluorescence confocal imaging of two fluorophores, methylene blue (MB) and demeclocycline (DMN). MB absorbs light in the red spectral range and fluoresces in the near-infrared. It is safe for in vivo staining of human skin and breast tissue. However, its safety for staining human brain is questionable. Thus, DMN, which absorbs light in the violet spectral range and fluoresces between 470 and 570 nm, could provide a safer alternative to MB. Fresh human gliomas, obtained from surgeries, were cut in half and stained with aqueous solutions of MB and DMN, respectively. Stained tissues were imaged using multimodal confocal microscopy. Resulting reflectance and fluorescence optical images were compared with hematoxylin and eosin histopathology, processed from each imaged tissue. Results indicate that images of tissues stained with either stain exhibit comparable contrast and resolution of morphological detail. Further studies are required to establish the safety and efficacy of these contrast agents for use in human brain.

  15. Enhanced photodynamic therapy efficacy of methylene blue-loaded calcium phosphate nanoparticles.

    PubMed

    Seong, Da-Young; Kim, Young-Jin

    2015-05-01

    Although methylene blue (MB) is the most inexpensive photosensitizer with promising applications in the photodynamic therapy (PDT) for its high quantum yield of singlet oxygen generation, the clinical use of MB has been limited by its rapid enzymatic reduction in the biological environment. To enhance PDT efficacy of MB by preventing the enzymatic reduction, we have developed a new mineralization method to produce highly biocompatible MB-loaded calcium phosphate (CaP-MB) nanoparticles in the presence of polymer templates. The resulting CaP-MB nanoparticles exhibited spherical shape with a size of under 50 nm. Fourier transform infrared (FT-IR) and zeta-potential analyses confirmed the insertion of MB into the CaP-MB nanoparticles. The encapsulation of MB in CaP nanoparticles could effectively protect MB from the enzymatic reduction. In addition, the CaP-MB nanoparticles exhibited a good biocompatibility in the dark condition and significantly enhanced PDT efficacy due to apoptotic cell death against human breast cancer cells as compared with free MB, implying that CaP-MB nanoparticle system might be potentially applicable in PDT.

  16. Graphene oxide mediated delivery of methylene blue for combined photodynamic and photothermal therapy.

    PubMed

    Sahu, Abhishek; Choi, Won Il; Lee, Jong Hyun; Tae, Giyoong

    2013-08-01

    Nano graphene oxide sheet (nanoGO) was non-covalently functionalized with Pluronic block copolymer and complexed with methylene blue, a hydrophilic and positively charged photosensitizer, via electrostatic interaction for combined photodynamic-photothermal therapy of cancer. Pluronic coating of nanoGO ensured its stability in biological fluids. NanoGO plays dual role of a photothermal material as well as a delivery agent for photosensitizer. The release of the photosensitizer from nanoGO surface was pH-dependent and an acidic condition increased the release rate considerably. This nanocomplex showed enhanced uptake by cancer cells than normal cells and in the absence of light it showed no major toxicity towards the cells. In contrast, when irradiated with selective NIR laser lights, it induced significant cell death. Intravenous injection of the complex into tumor bearing mice showed high tumor accumulation, and when the tumors were exposed to NIR lights, it caused total ablation of tumor tissue through the combined action of photodynamic and photothermal effects. This work shows the potential of nanoGO for synergistic combination phototherapy of tumor in vivo.

  17. Methylene blue-mediated photodynamic therapy enhances apoptosis in lung cancer cells.

    PubMed

    Lim, Eun Jin; Oak, Chul-Ho; Heo, Jeonghoon; Kim, Young-Ho

    2013-08-01

    Combined treatment with a photosensitizer and iodide laser [photodynamic therapy (PDT)] has improved the outcome of various cancers. In this study, we investigated the effects of using the photosensitizer methylene blue (MB) in PDT in human lung adenocarcinoma cells. We found that MB enhances PDT-induced apoptosis in association with downregulation of anti-apoptotic proteins, reduced mitochondrial membrane potential (MMP), increased phosphorylation of the mitogen-activated protein kinase (MAPK) and the generation of reactive oxygen species (ROS). In MB-PDT-treated A549 cells, we observed PARP cleavage, procaspase-3 activation, downregulation of the anti-apoptotic proteins Bcl-2 and Mcl-1, and the reduction of mitochondrial membrane potential (MMP). Western blot data showed that phosphorylation of p38 was increased in MB-PDT-treated A549 cells, indicating that several signaling molecules participate in the apoptotic cascade. Our data also showed that apoptotic cell death in MB-PDT-treated cells occurred through a series of steps beginning with the photochemical generation of ROS. Demonstrating the role of ROS, pretreatment of A549 cells with the antioxidant N-acetylcysteine (NAC) followed by MB-PDT resulted in increased cell viability and reduced proteolytic cleavage of PARP.

  18. Comparative evaluation of methylene blue and demeclocycline for enhancing optical contrast of gliomas in optical images

    NASA Astrophysics Data System (ADS)

    Wirth, Dennis; Snuderl, Matija; Curry, William; Yaroslavsky, Anna

    2014-09-01

    Contrast agents have shown to be useful in the detection of cancers. The goal of this study was to compare enhancement of brain cancer contrast using reflectance and fluorescence confocal imaging of two fluorophores, methylene blue (MB) and demeclocycline (DMN). MB absorbs light in the red spectral range and fluoresces in the near-infrared. It is safe for in vivo staining of human skin and breast tissue. However, its safety for staining human brain is questionable. Thus, DMN, which absorbs light in the violet spectral range and fluoresces between 470 and 570 nm, could provide a safer alternative to MB. Fresh human gliomas, obtained from surgeries, were cut in half and stained with aqueous solutions of MB and DMN, respectively. Stained tissues were imaged using multimodal confocal microscopy. Resulting reflectance and fluorescence optical images were compared with hematoxylin and eosin histopathology, processed from each imaged tissue. Results indicate that images of tissues stained with either stain exhibit comparable contrast and resolution of morphological detail. Further studies are required to establish the safety and efficacy of these contrast agents for use in human brain.

  19. Chemical convection in the methylene-blue-glucose system: Optimal perturbations and three-dimensional simulations

    NASA Astrophysics Data System (ADS)

    Köllner, Thomas; Rossi, Maurice; Broer, Frauke; Boeck, Thomas

    2014-11-01

    A case of convection driven by chemical reactions is studied by linear stability theory and direct numerical simulations. In a plane aqueous layer of glucose, the methylene-blue-enabled catalytic oxidation of glucose produces heavier gluconic acid. As the oxygen is supplied through the top surface, the production of gluconic acid leads to an overturning instability. Our results complement earlier experimental and numerical work by Pons et al. First, we extend the model by including the top air layer with diffusive transport and Henry's law for the oxygen concentration at the interface to provide a more realistic oxygen boundary condition. Second, a linear stability analysis of the diffusive basic state in the layers is performed using an optimal perturbation approach. This method is appropriate for the unsteady basic state and determines the onset time of convection and the associated wavelength. Third, the nonlinear evolution is studied by the use of three-dimensional numerical simulations. Three typical parameters sets are explored in detail showing significant differences in pattern formation. One parameter set for which the flow is dominated by viscous forces, displays persistently growing convection cells. The other set with increased reaction rate displays a different flow regime marked by local chaotic plume emission. The simulated patterns are then compared to experimental observations.

  20. Chemoconvection patterns in the methylene-blue-glucose system: Weakly nonlinear analysis

    NASA Astrophysics Data System (ADS)

    Pons, A. J.; Sagués, F.; Bees, M. A.

    2004-12-01

    The oxidation of solutions of glucose with methylene-blue as a catalyst in basic media can induce hydrodynamic overturning instabilities, termed chemoconvection in recognition of their similarity to convective instabilities. The phenomenon is due to gluconic acid, the marginally dense product of the reaction, which gradually builds an unstable density profile. Experiments indicate that dominant pattern wavenumbers initially increase before gradually decreasing or can even oscillate for long times. Here, we perform a weakly nonlinear analysis for an established model of the system with simple kinetics, and show that the resulting amplitude equation is analogous to that obtained in convection with insulating walls. We show that the amplitude description predicts that dominant pattern wavenumbers should decrease in the long term, but does not reproduce the aforementioned increasing wavenumber behavior in the initial stages of pattern development. We hypothesize that this is due to horizontally homogeneous steady states not being attained before pattern onset. We show that the behavior can be explained using a combination of pseudo-steady-state linear and steady-state weakly nonlinear theories. The results obtained are in qualitative agreement with the analysis of experiments.

  1. Adsorption of methylene blue and methyl red dyes from aqueous solutions onto modified zeolites.

    PubMed

    Ioannou, Z; Karasavvidis, Ch; Dimirkou, A; Antoniadis, V

    2013-01-01

    Zeolite, hematite, modified zeolite and commercial activated charcoal were examined for their ability to remove methylene blue (MB) and methyl red (MR) from their aqueous solutions. Modified zeolite and hematite were produced according to the Schwertmann and Cornell method while zeolite and commercial activated charcoal were obtained from S&B and Fluka AG companies, respectively. Adsorption experiments were conducted at three different adsorbent-to-solution ratios, namely 8, 16 and 24 g/L under environmental conditions and continuous stirring. Equilibrium isotherms of MB and MR were studied at different initial concentrations (from 5 × 10(-4) to 5 × 10(-3) g/L). MB adsorption kinetics were also studied. The maximum adsorption of MB and MR from their aqueous solutions was achieved at 24 g/L (adsorbent-to-dye solution ratio) after 1 h and was equal to 100% (MB) on modified zeolite and 99% (MR) on commercial activated charcoal, respectively. All the other materials achieved intermediate values of dye adsorption. From the applied kinetic models, the pseudo-second-order equation best described the adsorption of MB and MR. Consequently, modified zeolite showed the highest adsorption capacity for MB, while commercial activated charcoal showed the highest adsorption capacity of MR. The studied adsorbents can be used as filters to remove dyes from wastewaters.

  2. Effects of the oxidation degree of graphene oxide on the adsorption of methylene blue.

    PubMed

    Yan, Han; Tao, Xue; Yang, Zhen; Li, Kun; Yang, Hu; Li, Aimin; Cheng, Rongshi

    2014-03-15

    In this current work, a series of graphene oxides (GO) with different oxidation degrees (OD) was prepared using Hummer method. Fundamental adsorption behavior of the GO series for removal of methylene blue (MB) from aqueous solutions has been studied. The GO series shows an overall fast and pH-independent MB adsorption, which is even capable of removing trace levels of dye completely from very dilute solutions. Furthermore, the effects of the oxidation degree (OD) on MB adsorption behavior have been investigated systematically, indicating that the dye uptakes of GO exponentially increase with the increase of OD. Further study on the adsorption mechanism shows that adsorption behavior of GO would change from a Freundlich-type to a Langmuir-type adsorption as the OD increases. It may be due to both the enhanced exfoliation degree of the carbon planes in graphite caused by oxidation and the production of more active adsorption sites. The binding features of the MB loaded GO gradually change from MB molecule parallel stacking on graphite plane through hydrophobic π-π interaction to vertical standing via electrostatic interaction with increasing OD, resulting in a significant improvement of MB uptakes. In addition, the adsorption capacity of the regenerated GO has little loss until four cycles.

  3. Kinetics of competitive adsorption of β-casein and methylene blue on hydrophilic glass.

    PubMed

    Qi, Zhi-mei; Lu, Dan-feng; Deng, Lin; Matsuda, Naoki

    2012-03-01

    The competitive adsorption of methylene blue (MB) and β-casein on hydrophilic glass from an aqueous mixed solution was directly detected at the solution pH smaller than the protein isoelectric point (pI) by means of the waveguide-based broadband time-resolved evanescent wave absorption spectroscopy. The competitive adsorption causes the MB coverage to exponentially decrease with time from its peak value and prevents MB aggregation at the interface. The kinetic equation for the competitive adsorption of binary adsorbates was theoretically deduced based on the Langmuir model, and was used for creating the best fit to the experimental data. In the case of a fixed concentration of MB in the mixed solution, the best-fit parameter τ(-1) increases with the protein concentration at a specific pH and decreases with the solution pH at a given concentration of protein. The findings suggest that the β-casein concentration in sub-μM level can be rapidly determined by the time-resolved waveguide absorptiometry based on the competitive adsorption of MB and protein.

  4. Adsorption and Photocatalytic Degradation of Methylene Blue Using Potassium Polytitanate and Solar Simulator.

    PubMed

    Shahid, Mohammad; El Saliby, Ibrahim; McDonagh, Andrew; Chekli, Laura; Tijing, Leonard D; Kim, Jong-Ho; Shon, Ho Kyong

    2016-05-01

    Solar photocatalytic degradation of organic water pollutants can be used to degrade toxic organic pollutants in water. In this study, potassium titanate nanofibres were synthesized by an aqueous peroxide route at high pH and examined as photocatalysts for photodegradation of methylene blue (MB) using a solar simulator. Initially, MB was adsorbed on the surface of potassium polytitanates to achieve adsorption equilibrium before the photocatalysts were illuminated using solar simulator. The results showed that potassium polytitanate nanofibres were effective adsorbents of MB and also facilitated its photocatalytic degradation. Sulphate ion evolution during photocatalysis confirmed that some mineralisation occurred and hence photo-oxidative degradation of MB took place. The optimum operational conditions for the photocatalytic degradation of MB were found at 0.05 g/L of photocatalyst load, 10 mg/L MB and pH 7. The stability and regeneration of the photocatalyst specimen was also studied for 3 degradation cycles using adsorption/photocatalysis model. Morphological structure analysis of potassium titanate showed nanocrystallines structure of longitudinally-oriented isolated fibre with a length up to several micrometres with diameters ranging from 10 to 20 nanometres.

  5. Experimental Design Approach for Methylene Blue Dye Removal in Aqueous Environment by Nitrilotriacetic Modified Banana Pith.

    PubMed

    Lee, Shi-Ling; Liew, Shu-Wei; Ong, Siew-Teng

    2016-01-01

    Native banana pith (NBP) was modified by using nitrilotriacetic acid to increase its efficiency and adsorption capacity for methylene blue (MB) dye. The effect of various parameters such as pH, contact time and initial dye concentration, sorption isotherm and adsorbent dosage were studied. The maximum adsorption capacity of the NBP and NTA-BP is 100 and 142.86 mg/g, respectively. The IR spectrum of NBP and NTA-BP showed the presence of both carboxyl and hydroxyl groups. From the SEM micrographs, the surface morphology of NTA-BP before adsorption appeared to be smoother as compared to that after adsorption process. The pH(pzc) of NBP is 5.6 whereas for NTA-BP is 7.6. The experimental data fitted well into Langmuir isotherm with R(2) of 0.992. Plackett-Burman design was applied to identify the significant factors in affecting the uptake whereas the interaction between the factors and their optimum levels for the maximum percentage uptake of MB were determined using response surface methodology (RSM). Based on the results, the optimum condition for adsorption of MB was by using 0.06 g of NTA-BP in dye solution at pH 6 with 120 minutes contact time. The maximum adsorption of MB by NTA-BP achieved 99.42% under the optimum condition.

  6. Surface properties and adsorption characteristics to methylene blue and iodine of adsorbents from sludge.

    PubMed

    Deng, L Y; Xu, G R; Li, G B

    2010-01-01

    Adsorbent materials created from wastewater sludge have unique surface characteristics and could be effective in adsorption applications. In this research, the sludge-adsorbents were generated by pyrolyzing mixtures of sewage sludge and H(2)SO(4). Scanning electron microscope (SEM), thermal analysis, X-ray diffraction (XRD) and X-ray photoelectron spectroscope (XPS) were used to analyze the properties of sludge-adsorbent. XPS results show that the adsorbent surface functional groups with high contents of oxygen-containing groups serve as active sites for the adsorption and affect the surface characteristics; the adsorption mechanism of methylene blue (MB) is mainly Brönsted acid-base reaction between the adsorbent surface and MB; and iodine atoms are bonded to the surface of the adsorbent mainly by dispersive interactions rather than by electrostatic interactions. The results also show that H(2)SO(4) level, pyrolysis temperature and sulfuric acid/sludge weight ratio actually affected the adsorption characteristics. Using the conditions (H(2)SO(4) level of 1-18 M, pyrolysis temperature of 650°C, and weight ratio of 0.8), the adsorption capacities for MB and iodine were 74.7-62.3 mg g(-1) and 169.5-209.3 mg g(-1), respectively.

  7. Highly effective removal of Methylene Blue using functionalized attapulgite via hydrothermal process.

    PubMed

    Zhang, Zhifang; Wang, Wenbo; Wang, Aiqin

    2015-07-01

    Attapulgite (APT) has been frequently used for the adsorptive removal of dyes from aqueous solution owing to its unique one-dimensional nanoscale structure and low-cost, abundant, eco-friendly advantages. In this work, APT was functionalized under mild hydrothermal condition using chloroacetic acid (CA) with COOH functional groups to improve its adsorption properties. The effect of hydrothermal modification on the microstructure and physicochemical features of APT was investigated by Fourier transform infrared spectroscopy, X-ray diffraction and Field-emission scanning electron microscopy analyses. The effects of hydrothermal reaction parameters on the adsorption properties of modified APT were intensively investigated. It was revealed that the rearrangement of crystal structure and the surface functionalization of APT with COOH groups cause the surprising increase of adsorption capability for Methylene Blue (MB). The removal ratio of raw APT for MB is only 59.52%, while modified APT could almost completely remove MB in the 200 mg/L of MB solution with a removal ratio of 99.8%. The adsorption kinetics fitted pseudo second-order kinetic model, and the adsorption isotherm could be described with Langmuir isotherm model very well. The hydrogen-bonding interaction, electrostatic attraction and chemical association are the main driving force for the adsorption process.

  8. [Adsorption properties of modified graphene for methylene blue removal from wastewater].

    PubMed

    Wu, Yan; Luo, Han-Jin; Wang, Hou; Zhang, Zi-Long; Wang, Can; Wang, Yu-Wei

    2013-11-01

    In this study, cetyltrimethylammonium bromide (CTAB) was chosen to modify graphene, which was applied to remove methylene blue (MB) from aqueous solutions. The characteristics of graphene and modified graphene were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), thermal gravimetric analyzer (TGA), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The effects of factors including pH, contact time, temperature, and dosage on the adsorption properties of MB onto graphene and modified graphene were investigated. The results revealed that the addition of CTAB in preparation could obviously increase the specific surface area and improve the efficiency of removal. The adsorption processes were rapid within the first 15 min and reached equilibrium in about 120 min. The adsorption kinetics fitted well with the pseudo-second-order model. The optimal reaction temperature was 293 K, the optimal concentration of adsorbent dosage was 2 g x L(-1), and the initial pH value of the solution had little impact on the amount of adsorption. The adsorption capacity of MB on modified graphene inferred from the Langmuir model was 86.43 mg x g(-1) at 293 K, and the adsorption was an exothermic process.

  9. Preparation of modified semi-coke by microwave heating and adsorption kinetics of methylene blue.

    PubMed

    Wang, Xin; Peng, Jin-Hui; Duan, Xin-Hui; Srinivasakannan, Chandrasekar

    2013-01-01

    Preparation of modified semi-coke has been achieved, using phosphoric acid as the modifying agent, by microwave heating from virgin semi-coke. Process optimization using a Central Composite Design (CCD) design of Response Surface Methodology (RSM) technique for the preparation of modifies semi-coke is presented in this paper. The optimum conditions for producing modified semi-coke were: concentration of phosphoric acid 2.04, heating time 20 minutes and temperature 587 degrees C, with the optimum iodine of 862 mg/g and yield of 47.48%. The textural characteristics of modified semi-coke were analyzed using scanning electron microscopy (SEM) and nitrogen adsorption isotherm. The BET surface area of modified semi-coke was estimated to be 989.60 m2/g, with the pore volume of 0.74 cm3/g and a pore diameter of 3.009 nm, with micro-pore volume contributing to 62.44%. The Methylene Blue monolayer adsorption capacity was found to be mg/g at K. The adsorption capacity of the modified semi-coke highlights its suitability for liquid phase adsorption application with a potential usage in waste water treatment.

  10. Activated carbon coated palygorskite as adsorbent by activation and its adsorption for methylene blue.

    PubMed

    Zhang, Xianlong; Cheng, Liping; Wu, Xueping; Tang, Yingzhao; Wu, Yucheng

    2015-07-01

    An activation process for developing the surface and porous structure of palygorskite/carbon (PG/C) nanocomposite using ZnCl2 as activating agent was investigated. The obtained activated PG/C was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (SEM), and Brunauer-Emmett-Teller analysis (BET) techniques. The effects of activation conditions were examined, including activation temperature and impregnation ratio. With increased temperature and impregnation ratio, the collapse of the palygorskite crystal structure was found to accelerate and the carbon coated on the surface underwent further carbonization. XRD and SEM data confirmed that the palygorskite structure was destroyed and the carbon structure was developed during activation. The presence of the characteristic absorption peaks of CC and C-H vibrations in the FTIR spectra suggested the occurrence of aromatization. The BET surface area improved by more than 11-fold (1201 m2/g for activated PG/C vs. 106 m2/g for PG/C) after activation, and the material appeared to be mainly microporous. The maximum adsorption capacity of methylene blue onto the activated PG/C reached 351 mg/g. The activated PG/C demonstrated better compressive strength than activated carbon without palygorskite clay.

  11. Sulfur K-edge XANES for methylene blue in photocatalytic reaction over WO3 nanomaterials

    NASA Astrophysics Data System (ADS)

    Komori, K.; Yoshida, T.; Nomoto, T.; Yamamoto, M.; Tsukada, C.; Yagi, S.; Yajima, M.; Kajita, S.; Ohno, N.

    2015-12-01

    We investigated the photocatalysis of dendritic nanostructured WO3/W composite materials fabricated by He plasma irradiation to tungsten plates, followed by the surface oxidation. The samples promoted the decolorization reaction of methylene blue (MB) aqueous solution under near infrared (NIR) light irradiation. To verify the MB molecule is actually decomposed by the photocatalysis of the samples, reaction products were analyzed by S K-edge XANES measurements for the MB solution kept with the samples under the light irradiation or in the dark. By the light irradiation, the σ*(S-C) peak in the XANES spectra reduced and a new peak originated from SO42- species was clearly observed, suggesting that S-C bonds in a MB molecule are broken by the NIR light irradiation and finally the sulfur species exists in the solution in the state of SO42- ion. After the adsorption reaction in the dark, the XANES spectra of the sample surfaces showed a sharp π*(S-C) peaks, indicating that MB molecules are adsorbed on the sample surfaces and stacked each other by the π-π interaction. These results demonstrate that the photocatalytic decomposition of MB molecules really proceeds over WO3/W composite materials even under NIR light irradiation.

  12. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles.

    PubMed

    Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

    2016-01-01

    Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R (2) values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R (2) values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents.

  13. The preparation of novel adsorbent materials with efficient adsorption performance for both chromium and methylene blue.

    PubMed

    Li, Leilei; Liu, Feng; Duan, Huimin; Wang, Xiaojiao; Li, Jianbo; Wang, Yanhui; Luo, Chuannan

    2016-05-01

    The hydroxy-functionalized ionic liquids (ILs) modified with magnetic chitosan/grapheneoxide (MG-ILs-OH) were synthesized. The surface morphology of MG-ILs-OH was characterized by transmission electron microscopy, X-ray diffraction, thermo gravimetric analysis and Fourier transform infrared spectroscopy techniques. It was found that the adsorption kinetics is well fitted by a pseudo-second-order model and the adsorption isotherms agree well with the Langmuir model, and the MG-ILs-OH could be repeatedly used by simple treatment. The results showed that the addition of ILs-OH can largely increase the adsorption sites (hydroxy and amino groups) and adsorption properties. The MG-ILs-OH were used as adsorbent for the removal of methylene blue (MB) and Cr(VI) from simulated wastewater with a fast solid-liquid separation in the presence of external magnetic field. The maximum obtained adsorption capacities of MB and Cr(VI) were 243.31 and 107.99 mg/g, respectively. The application of MG-ILs-OH could effectively solve the problem that the adsorbent only adsorb similar adsorbate.

  14. Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes.

    PubMed

    Szlachta, M; Wójtowicz, P

    2013-01-01

    This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m(2)/g, MWCNTs 358 m(2)/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal.

  15. Removal of methylene blue from aqueous solution by wood millet carbon optimization using response surface methodology.

    PubMed

    Ghaedi, Mehrorang; Nasiri Kokhdan, Syamak

    2015-02-01

    The use of cheep, non-toxic, safe and easily available adsorbent are efficient and recommended material and alternative to the current expensive substance for pollutant removal from wastewater. The activated carbon prepared from wood waste of local tree (millet) extensively was applied for quantitative removal of methylene blue (MB), while simply. It was used to re-used after heating and washing with alkaline solution of ethanol. This new adsorbent was characterized by using BET surface area measurement, FT-IR, pH determination at zero point of charge (pHZPC) and Boehm titration method. Response surface methodology (RSM) by at least the number of experiments main and interaction of experimental conditions such as pH of solution, contact time, initial dye concentration and adsorbent dosage was optimized and set as pH 7, contact time 18 min, initial dye concentration 20 ppm and 0.2 g of adsorbent. It was found that variable such as pH and amount of adsorbent as solely or combination effects seriously affect the removal percentage. The fitting experimental data with conventional models reveal the applicability of isotherm models Langmuir model for their well presentation and description and Kinetic real rate of adsorption at most conditions efficiently can be represented pseudo-second order, and intra-particle diffusion. It novel material is good candidate for removal of huge amount of MB (20 ppm) in short time (18 min) by consumption of small amount (0.2 g).

  16. High-pressure homogenization associated hydrothermal process of palygorskite for enhanced adsorption of Methylene blue

    NASA Astrophysics Data System (ADS)

    Zhang, Zhifang; Wang, Wenbo; Wang, Aiqin

    2015-02-01

    Palygorskite (PAL) was modified by a high-pressure homogenization assisted hydrothermal process. The effects of modification on the morphology, structure and physicochemical properties of PAL were systematically investigated by Field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FTIR), Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction (XRD) and Zeta potential analysis techniques, and the adsorption properties were systematically evaluated using Methylene blue (MB) as the model dye. The results revealed that the crystal bundles were disaggregated and the PAL nanorods became more even after treated via associated high-pressure homogenization and hydrothermal process, and the crystal bundles were dispersed as nanorods. The intrinsic crystal structure of PAL was remained after hydrothermal treatment, and the pore size calculated by the BET method was increased. The adsorption properties of PAL for MB were evidently improved (from 119 mg/g to 171 mg/g) after modification, and the dispersion of PAL before hydrothermal reaction is favorable to the adsorption. The desorption evaluation confirms that the modified PAL has stronger affinity with MB, which is benefit to fabricate a stable organic-inorganic hybrid pigment.

  17. Mechanism of Adsorptive Removal of Methylene Blue Using Dried Biomass of Rhizopus oryzae.

    PubMed

    Dey, Manash Deep; Shukla, Ruchi; Bordoloi, Naba K; Doley, Robin; Mukhopadhyay, Rupak

    2015-09-01

    Adsorption is an efficient way to remove synthetic dyes from industrial effluent. Here, we show mechanism of adsorptive removal of cationic dye methylene blue (MB) from its aqueous solution using dried biomass of Rhizopus oryzae as a biosorbent. The optimum pH and temperature for adsorption was found to be 7.0 and 28 °C, respectively. Scanning electron microscopy (SEM) of the biomass suggested distinct changes in surface topology post-MB adsorption, while Fourier transform infrared (FTIR) study indicated chemical interaction between the surface of the biomass and MB. Chemical modification of -OH and -C=O groups of biomass reduced the MB adsorption and corroborated with the FTIR analyses. Kinetics study revealed that the adsorption rate was fast initially and reached equilibrium at 4 h following a pseudo-second-order-kinetics. The adsorption isotherm followed Freundlich isotherm model with n value of 1.1615.The dried biomass of R. oryzae can be used as a potent biosorbent for the removal of MB.

  18. Adsorption of methylene blue on biochar microparticles derived from different waste materials.

    PubMed

    Lonappan, Linson; Rouissi, Tarek; Das, Ratul Kumar; Brar, Satinder K; Ramirez, Antonio Avalos; Verma, Mausam; Surampalli, Rao Y; Valero, José R

    2016-03-01

    Biochar microparticles were prepared from three different types of biochar, derived from waste materials, such as pine wood (BC-PW), pig manure (BC-PM) and cardboard (BC-PD) under various pyrolysis conditions. The microparticles were prepared by dry grinding and sequential sieving through various ASTM sieves. Particle size and specific surface area were analyzed using laser particle size analyzer. The particles were further characterized using scanning electron microscope (SEM). The adsorption capacity of each class of adsorbent was determined by methylene blue adsorption tests in comparison with commercially available activated carbon. Experimental results showed that dye adsorption increased with initial concentration of the adsorbate and biochar dosage. Biochar microparticles prepared from different sources exhibited improvement in adsorption capacity (7.8±0.5 mg g(-1) to 25±1.3 mg g(-1)) in comparison with raw biochar and commercially available activated carbon. The adsorption capacity varied with source material and method of production of biochar. The maximum adsorption capacity was 25 mg g(-1) for BC-PM microparticles at 25°C for an adsorbate concentration of 500 mg L(-1) in comparison with 48.30±3.6 mg g(-1) for activated carbon. The equilibrium adsorption data were best described by Langmuir model for BC-PM and BC-PD and Freundlich model for BC-PW.

  19. Removal of methylene blue from aqueous solutions by chemically modified bamboo.

    PubMed

    Guo, Jian-Zhong; Li, Bing; Liu, Li; Lv, Kangle

    2014-09-01

    Chemically modified bamboo (CMB) was utilized for removing methylene blue (MB) from aqueous media in the present study. The adsorbent was characterized by Fourier transform infrared (FTIR) spectra and elemental analysis, which confirms that carboxyl groups and diethylenetriamine were successfully introduced into the surface of bamboo. The effects of initial MB concentration (100-900mgL(-1)), contact time (15-315min), the pH of the solution (3-10), temperature (298-318K), adsorbent dosage (0.4-2.6gL(-1)) and salt concentration on the adsorption efficiency of CMB towards MB were investigated. It was found that the adsorption of MB in CMB fits Langmuir mode well, and the maximum adsorption capacity of CMB achieved 606mgg(-1) at 298K, which is much higher than those obtained from previously investigated bioadsorbents. The adsorption kinetics can be described by pseudo-second-order kinetic model, and the adsorption of MB on CMB was an exothermic process. The results of the present study suggest that CMB is an effective biosorbent for removal of organic pollutants from aqueous solutions.

  20. Adsorption of methylene blue on biochar microparticles derived from different waste materials.

    PubMed

    Lonappan, Linson; Rouissi, Tarek; Das, Ratul Kumar; Brar, Satinder K; Ramirez, Antonio Avalos; Verma, Mausam; Surampalli, Rao Y; Valero, José R

    2016-03-01

    Biochar microparticles were prepared from three different types of biochar, derived from waste materials, such as pine wood (BC-PW), pig manure (BC-PM) and cardboard (BC-PD) under various pyrolysis conditions. The microparticles were prepared by dry grinding and sequential sieving through various ASTM sieves. Particle size and specific surface area were analyzed using laser particle size analyzer. The particles were further characterized using scanning electron microscope (SEM). The adsorption capacity of each class of adsorbent was determined by methylene blue adsorption tests in comparison with commercially available activated carbon. Experimental results showed that dye adsorption increased with initial concentration of the adsorbate and biochar dosage. Biochar microparticles prepared from different sources exhibited improvement in adsorption capacity (7.8±0.5 mg g(-1) to 25±1.3 mg g(-1)) in comparison with raw biochar and commercially available activated carbon. The adsorption capacity varied with source material and method of production of biochar. The maximum adsorption capacity was 25 mg g(-1) for BC-PM microparticles at 25°C for an adsorbate concentration of 500 mg L(-1) in comparison with 48.30±3.6 mg g(-1) for activated carbon. The equilibrium adsorption data were best described by Langmuir model for BC-PM and BC-PD and Freundlich model for BC-PW. PMID:26818183

  1. Enhanced photocatalytic activity of TiO2-C hybrid aerogels for methylene blue degradation

    NASA Astrophysics Data System (ADS)

    Shao, Xia; Lu, Wencong; Zhang, Rui; Pan, Feng

    2013-10-01

    Carbon-based TiO2 composites have many advantages as photocatalysts. However, they suffer from low light efficiency due to the low contrast of TiO2 with carbon. We synthesized a novel type of anatase-type TiO2-C hybrid aerogel by a one-pot sol-gel method, which shows a photocatalytic activity for methylene degradation up to 4.23 times that of P25, a commercial photocatalyst from Degussa Inc. The hybrid aerogels are prepared from TiCl4 and resorcinol-furfural, and have a tunable macropore size from 167 to 996 nm. They are formed of submicrometer particles that consist of interwoven anatase and carbon nanoparticles. The anatase nanoparticles have a size of 8-9 nm and a tunable oxygen vacancy from 7.2 to 18.0%. The extremely high activity is ascribed to the large light absorption caused by macropore scattering and oxygen vacancies in the anatase. These findings may open up a new avenue and stimulate further research to improve photocatalytic performance.

  2. Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars

    PubMed Central

    Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong

    2016-01-01

    Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB. PMID:27144922

  3. Inhibition of postsurgical adhesions by methylene blue-loaded nanofibers versus cast film matrices.

    PubMed

    El-Sayed, Nesma; Galal, Sally; El-Gowelli, Hanan; El-Khordagui, Labiba

    2016-07-01

    In the quest for barrier membranes for the prevention of post-surgical tissue adhesions, polymer matrices may provide a platform of biomaterials with versatile properties. However, the relationship between the anti-adhesion effects of different polymer matrices and their physicochemical and structural properties is not yet adequately understood. In a preclinical study using a rat cecum model, we directly compared the anti-adhesion potential of polyhydroxybutyrate (PHB) electrospun nanofibrous versus cast film matrices loaded with methylene blue (MB) as antioxidant adhesion inhibitor. PHB retained MB presumably forming MB-bioactivated matrices. In the preclinical study, quantitative morphologic assessment in addition to histopathologic and SEM examinations 14 days post-surgery indicated that plain PHB NFs and MB-PHB NFs, moderately enhanced cecal wall healing and inhibited adhesion formation. In contrast, reshaping PHB as cast films, significantly enhanced healing, reduced adhesion bands and prevented inter-visceral adhesions. Cast films also inhibited tissue attachment to the matrix recovered 14 days post-surgery. Both PHB matrix types reduced tissue inflammation. Despite tissue anti-adhesion potential of individual matrix components, modulation of the micro-architectural properties generated polymer barriers with varying tissue anti-adhesion and healing potentials, the MB-loaded cast film achieving the best outcome.

  4. Removal of methylene blue from aqueous solution by Artist's Bracket fungi: kinetic and equilibrium studies.

    PubMed

    Naghipour, Daryush; Taghavi, Kamran; Moslemzadeh, Mehrdad

    2016-01-01

    In this study, adsorption of methylene blue (MB) dye onto Artist's Bracket (AB) fungi was investigated in aqueous solution. Fourier transform infrared and scanning electron microscopy were used to investigate surface characteristic of AB fungi. Influence of operational parameters such as pH, contact time, biosorbent dosage, dye concentration, inorganic salts and temperature was studied on dye removal efficiency. With the increase of pH from 3 to 9, removal efficiency increased from 74.0% to 90.4%. Also, it reduced from 99.8% to 81.8% with increasing initial MB concentration from 25 mg L(-1) to 100 mg L(-1), whereas it increased from 54.7% to 98.7% and from 98.5% to 99.9% with increasing biosorbent dosage from 0.5 g L(-1) to 2 g L(-1) and with increasing temperature from 25 °C to 50 °C, respectively. Isotherm studies have shown adsorption of MB dye over the AB fungi had a better coefficient of determination (R(2)) of 0.98 for Langmuir isotherm. In addition, the maximum monolayer adsorption capacity (qm) was 100 mg g(-1). Also, the MB dye adsorption process followed pseudo-second-order kinetic. In general, AB fungi particles can be favorable for removal of MB dye from dye aqueous solution with natural pH and high temperature. PMID:27232421

  5. Enzymatic hydroxylation of an unactivated methylene C-H bond guided by molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Narayan, Alison R. H.; Jiménez-Osés, Gonzalo; Liu, Peng; Negretti, Solymar; Zhao, Wanxiang; Gilbert, Michael M.; Ramabhadran, Raghunath O.; Yang, Yun-Fang; Furan, Lawrence R.; Li, Zhe; Podust, Larissa M.; Montgomery, John; Houk, K. N.; Sherman, David H.

    2015-08-01

    The hallmark of enzymes from secondary metabolic pathways is the pairing of powerful reactivity with exquisite site selectivity. The application of these biocatalytic tools in organic synthesis, however, remains under-utilized due to limitations in substrate scope and scalability. Here, we report how the reactivity of a monooxygenase (PikC) from the pikromycin pathway is modified through computationally guided protein and substrate engineering, and applied to the oxidation of unactivated methylene C-H bonds. Molecular dynamics and quantum mechanical calculations were used to develop a predictive model for substrate scope, site selectivity and stereoselectivity of PikC-mediated C-H oxidation. A suite of menthol derivatives was screened computationally and evaluated through in vitro reactions, where each substrate adhered to the predicted models for selectivity and conversion to product. This platform was also expanded beyond menthol-based substrates to the selective hydroxylation of a variety of substrate cores ranging from cyclic to fused bicyclic and bridged bicyclic compounds.

  6. Prokineticin 2 facilitates mechanical allodynia induced by α,β-methylene ATP in rats.

    PubMed

    Ren, Cuixia; Qiu, Chun-Yu; Gan, Xiong; Liu, Ting-Ting; Qu, Zu-Wei; Rao, Zhiguo; Hu, Wang-Ping

    2015-11-15

    Prokineticin 2 (PK2), a new chemokine, causes mechanical hypersensitivity in the rat hind paw, but little is known about the molecular mechanism. Here, we have found that ionotropic P2X receptor is essential to mechanical allodynia induced by PK2. First, intraplantar injection of high dose (3 or 10 pmol) of PK2 significantly increased paw withdrawal response frequency (%) to innocuous mechanical stimuli (mechanical allodynia). And the mechanical allodynia induced by PK2 was prevented by co-administration of TNP-ATP, a selective P2X receptor antagonist. Second, although low dose (0.3 or 1 pmol) of PK2 itself did not produce an allodynic response, it significantly facilitated the mechanical allodynia evoked by intraplantar injection of α,β-methylene ATP (α,β-meATP). Third, PK2 concentration-dependently potentiated α,β-meATP-activated currents in rat dorsal root ganglion (DRG) neurons. Finally, PK2 receptors and intracellular signal transduction were involved in PK2 potentiation of α,β-meATP-induced mechanical allodynia and α,β-meATP-activated currents, since the potentiation were blocked by PK2 receptor antagonist PKRA and selective PKC inhibitor GF 109203X. These results suggested that PK2 facilitated mechanical allodynia induced by α,β-meATP through a mechanism involved in sensitization of cutaneous P2X receptors expressed by nociceptive nerve endings.

  7. Methylene Blue Reduces Acute Cerebral Ischemic Injury via the Induction of Mitophagy.

    PubMed

    Di, Yao; He, Yun-Ling; Zhao, Tong; Huang, Xin; Wu, Kui-Wu; Liu, Shu-Hong; Zhao, Yong-Qi; Fan, Ming; Wu, Li-Ying; Zhu, Ling-Ling

    2015-05-19

    The treatment of stroke is limited by a short therapeutic window and a lack of effective clinical drugs. Methylene blue (MB) has been used in laboratories and clinics since the 1890s. Few studies have reported the neuroprotective role of MB in cerebral ischemia-reperfusion injury. However, whether and how MB protects against acute cerebral ischemia (ACI) injury was unclear. In this study, we investigated the effect of MB on this injury and revealed that MB protected against ACI injury by augmenting mitophagy. Using a rat middle cerebral artery occlusion (MCAO) model, we demonstrated that MB improved neurological function and reduced the infarct volume and necrosis after ACI injury. These improvements depended on the effect of MB on mitochondrial structure and function. ACI caused the disorder and disintegration of mitochondrial structure, while MB ameliorated the destruction of mitochondria. In addition, mitophagy was inhibited at 24 h after stroke and MB augmented mitophagy. In an oxygen-glucose deprivation (OGD) model in vitro, we further revealed that the elevation of mitochondrial membrane potential (MMP) by MB under OGD conditions mediated the augmented mitophagy. In contrast, exacerbating the decline of MMP during OGD abolished the MB-induced activation of mitophagy. Taken together, MB promotes mitophagy by maintaining the MMP at a relatively high level, which contributes to a decrease in necrosis and an improvement in neurological function, thereby protecting against ACI injury.

  8. Cationic Methylene-Pyrene Isomers and Isomerization Pathways: Finite Temperature Theoretical Studies.

    PubMed

    Rapacioli, Mathias; Simon, Aude; Marshall, Charlotte C M; Cuny, Jérôme; Kokkin, Damian; Spiegelman, Fernand; Joblin, Christine

    2015-12-24

    This paper provides spectral characterizations of the two isomers of the 1-methylenepyrene cation, namely, the 1-pyrenemethylium and a pyrene-like isomer owing a tropylium cycle. Both are possible photodissociation products of the 1-methylpyrene cation and were proposed as potential contributors to the diffuse interstellar bands. In that respect, vibrational and electronic spectra are computed for the optimized structures at the density functional theory (DFT) and time-dependent (TD-)DFT levels. Finite temperature effects on these spectra are estimated from molecular dynamics simulations within the density functional-based tight-binding (DFTB) and TD-DFTB frameworks, these methods being first benchmarked against DFT and TD-DFT calculations. The computed spectra allow discrimination of the two isomers. When the temperature increases, bands are observed to redshift and merge. The isomerization mechanism is investigated with the metadynamics technique, a biased dynamics scheme allowing to probe reaction mechanisms with high energy barriers by investigating the free energy surface at various temperatures. Four pathways with similar barrier heights (3.5-4 eV) are found, showing that the interconversion process would only occur in interstellar clouds under photoactivation. The present study opens the way to simulations on larger methyl- and methylenePAHs of astrophysical interest and their experimental investigation.

  9. Removal of methylene blue from aqueous solution by wood millet carbon optimization using response surface methodology

    NASA Astrophysics Data System (ADS)

    Ghaedi, Mehrorang; Kokhdan, Syamak Nasiri

    2015-02-01

    The use of cheep, non-toxic, safe and easily available adsorbent are efficient and recommended material and alternative to the current expensive substance for pollutant removal from wastewater. The activated carbon prepared from wood waste of local tree (millet) extensively was applied for quantitative removal of methylene blue (MB), while simply. It was used to re-used after heating and washing with alkaline solution of ethanol. This new adsorbent was characterized by using BET surface area measurement, FT-IR, pH determination at zero point of charge (pHZPC) and Boehm titration method. Response surface methodology (RSM) by at least the number of experiments main and interaction of experimental conditions such as pH of solution, contact time, initial dye concentration and adsorbent dosage was optimized and set as pH 7, contact time 18 min, initial dye concentration 20 ppm and 0.2 g of adsorbent. It was found that variable such as pH and amount of adsorbent as solely or combination effects seriously affect the removal percentage. The fitting experimental data with conventional models reveal the applicability of isotherm models Langmuir model for their well presentation and description and Kinetic real rate of adsorption at most conditions efficiently can be represented pseudo-second order, and intra-particle diffusion. It novel material is good candidate for removal of huge amount of MB (20 ppm) in short time (18 min) by consumption of small amount (0.2 g).

  10. Adsorption of methylene blue onto hazelnut shell: Kinetics, mechanism and activation parameters.

    PubMed

    Doğan, Mehmet; Abak, Harun; Alkan, Mahir

    2009-05-15

    The adsorption kinetics of methylene blue (MB) on the hazelnut shell with respect to the initial dye concentration, pH, ionic strength, particle size and temperature were investigated. The rate and the transport/kinetic processes of MB adsorption were described by applying the first-order Lagergren, the pseudo-second-order, mass transfer coefficient and the intraparticle diffusion models. Kinetic studies showed that the kinetic data were well described by the pseudo-second-order kinetic model. Significant increases in initial adsorption rate were observed with the increase in temperature followed by pH and initial MB concentration. The intraparticle diffusion was found to be the rate-limiting step in the adsorption process. Adsorption activation energy was calculated to be 45.6kJmol(-1). The values of activation parameters such as free energy (DeltaG(*)), enthalpy (DeltaH(*)) and entropy (DeltaS(*)) were also determined as 83.4kJmol(-1), 42.9kJmol(-1) and -133.5Jmol(-1)K(-1), respectively.

  11. Control of burn wound sepsis in rats by methylene blue-mediated photodynamic treatment

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroyuki; Sato, Shunichi; Kawauchi, Satoko; Saitoh, Daizoh; Shinomiya, Nariyoshi; Ashida, Hiroshi; Terakawa, Mitsuhiro

    2012-02-01

    Control of wound sepsis is an important challenge in traumatology. However, increase in the drug-resistant bacteria makes this challenge considerably difficult in recent years. In this study, we attempted to control burn wound sepsis in rats by photodynamic treatment, which has been reported to be effective against some drug-resistant bacteria. A 20% TBSA (total body surface area) full-thickness burn was made in rat dorsal skin, and five days after injury, a suspension of P. aeruginosa was applied to the wound surface. At 30 min after infection, a methylene blue (MB) solution was applied to the wound surface; 5 min afterwards, the wound was illuminated with a 665-nm light emitting diode (LED) array for 10 min. This treatment (application of MB and illumination) was repeated 3 times successively. The averaged light intensity on the wound surface was 3.3 mW/cm2, the corresponding total light dose being 5.9 J/cm2. One week after injury, the numbers of bacteria in the blood and liver were counted by colony forming assay. In the liver, the number of bacteria of the treated group was significantly lower than that of the sham control group without photodynamic treatment. In the blood, no bacteria were detected in the treated group, while a certain amount of bacteria was detected in the control group. These results demonstrate the efficacy of MB-mediated PDT with a red LED array to control burn wound sepsis.

  12. Methylene blue biosorption by pericarp of corn, alfalfa, and agave bagasse wastes.

    PubMed

    Rosas-Castor, José M; Garza-González, María T; García-Reyes, Refugio B; Soto-Regalado, Eduardo; Cerino-Córdova, Felipe J; García-González, Alcione; Loredo-Medrano, José A

    2014-01-01

    The presence of dyes in effluent is a matter of concern due to their toxicologic and aesthetical effects. In this research, locally available agro-industrial wastes (Zea mays pericarp, ZMP; Agave tequilana bagasse, ATB; and Medicago sativa waste, MSW) were used as alternative low-cost adsorbents for the removal of methylene blue (MB) from aqueous solutions. The adsorbents were characterized physically and chemically by Fourier transform infrared, scanning electron microscopy, potentiometric titrations, and N2 physisorption. MB adsorption experiments were carried out in batch systems and experimental data were used to calculate the adsorption isotherm model parameters (Langmuir, Freundlich, and Temkin) and the adsorption kinetic model parameters (pseudo-first- and pseudo-second-order models). MB-loaded biosorbents were desorbed with deionized water, ethanol (10% and 50% v/v), hydrochloric acid (0.01 and 0.05 N), and sodium hydroxide (0.1 N) at room temperature, and the best eluent was used in various adsorption-desorption cycles. The selected agricultural wastes can be considered as promising adsorbents for dye uptake from water since they exhibit considerable MB adsorption capacity (MSW 202.6 mg g(-1), ATB 156.2mg g(-1), and ZMP 110.9mg g(-1)), but it is lower than that reported for activated carbon; however, the biosorbents show higher adsorption rate than powdered activated carbon. Furthermore, the adsorbents can be economically regenerated with HCl solutions and reused for seven adsorption-desorption cycles. PMID:24701903

  13. Inhibition of postsurgical adhesions by methylene blue-loaded nanofibers versus cast film matrices.

    PubMed

    El-Sayed, Nesma; Galal, Sally; El-Gowelli, Hanan; El-Khordagui, Labiba

    2016-07-01

    In the quest for barrier membranes for the prevention of post-surgical tissue adhesions, polymer matrices may provide a platform of biomaterials with versatile properties. However, the relationship between the anti-adhesion effects of different polymer matrices and their physicochemical and structural properties is not yet adequately understood. In a preclinical study using a rat cecum model, we directly compared the anti-adhesion potential of polyhydroxybutyrate (PHB) electrospun nanofibrous versus cast film matrices loaded with methylene blue (MB) as antioxidant adhesion inhibitor. PHB retained MB presumably forming MB-bioactivated matrices. In the preclinical study, quantitative morphologic assessment in addition to histopathologic and SEM examinations 14 days post-surgery indicated that plain PHB NFs and MB-PHB NFs, moderately enhanced cecal wall healing and inhibited adhesion formation. In contrast, reshaping PHB as cast films, significantly enhanced healing, reduced adhesion bands and prevented inter-visceral adhesions. Cast films also inhibited tissue attachment to the matrix recovered 14 days post-surgery. Both PHB matrix types reduced tissue inflammation. Despite tissue anti-adhesion potential of individual matrix components, modulation of the micro-architectural properties generated polymer barriers with varying tissue anti-adhesion and healing potentials, the MB-loaded cast film achieving the best outcome. PMID:27093975

  14. The hemodynamic effects of methylene blue when administered at the onset of cardiopulmonary bypass.

    PubMed

    Maslow, Andrew D; Stearns, Gary; Butala, Parag; Batula, Parag; Schwartz, Carl S; Gough, Jeffrey; Singh, Arun K

    2006-07-01

    Hypotension occurs during cardiopulmonary bypass (CPB), in part because of induction of the inflammatory response, for which nitric oxide and guanylate cyclase play a central role. In this study we examined the hemodynamic effects of methylene blue (MB), an inhibitor of guanylate cyclase, administered during cardiopulmonary bypass (CPB) to patients taking angiotensin-converting enzyme inhibitors. Thirty patients undergoing cardiac surgery were randomized to receive either MB (3 mg/kg) or saline (S) after institution of CPB and cardioplegic arrest. CPB was managed similarly for all study patients. Hemodynamic data were assessed before, during, and after CPB. The use of vasopressors was recorded. All study patients experienced a similar reduction in mean arterial blood pressure (MAP) and systemic vascular resistance (SVR) with the onset of CPB and cardioplegic arrest. MB increased MAP and SVR and this effect lasted for 40 minutes. The saline group demonstrated a persistently reduced MAP and SVR throughout CPB. The saline group received phenylephrine more frequently during CPB, and more norepinephrine after CPB to maintain a desirable MAP. The MB group recorded significantly lower serum lactate levels despite equal or greater MAP and SVR. In conclusion, administration of MB after institution of CPB for patients taking angiotensin-converting enzyme inhibitors increased MAP and SVR and reduced the need for vasopressors. Furthermore, serum lactate levels were lower in MB patients, suggesting more favorable tissue perfusion. PMID:16790616

  15. Decolourization of Methylene Blue in Water Using Bentonite Impregnated with Ti and Ag as Photocatalyst.

    PubMed

    Wu, Edward Ming-Yang; Kuo, Shu-Lung

    2015-08-01

    This article used bentonite impregnated with titanium and silver, respectively, as photocatalyst, to degrade methylene blue (MB) under conditions of MB solutions exposed to sodium lamp and sunlight. Due to the semi-conducting properties of synthesized bentonite catalysts, when exposed to sodium lamp and sunlight, catalyst particles are excited for photocatalysis to achieve decolourization. After an FT-IR analysis, this study finds that smectite catalysts have significant and complicated wave crests between the fingerprint area with wave numbers 415~600 cm⁻¹ and 750~1170 cm⁻¹. The bentonite impregnated with Ti(4+) (Sm-Ti) and with Ag⁺ (Sm-Ag) removes MB through the mechanisms of adsorption and degradation, while the commercial product of titanium dioxide (TiO₂) only exhibits the capability of MB degradation. At present, a heterogeneous photocatalytic system has been fully applied for use in daily life, with its efficiency determined by the free radical action of electrons and holes, the generation efficiency of ·OH.

  16. Papain gel containing methylene blue for simultaneous caries removal and antimicrobial photoinactivation against Streptococcus mutans biofilms

    PubMed Central

    Silva Jr., Zenildo Santos; Huang, Ying-Ying; de Freitas, Lucas Freitas; França, Cristiane Miranda; Botta, Sergio Brossi; Ana, Patrícia Aparecida; Mesquita-Ferrari, Raquel Agnelli; Santos Fernandes, Kristianne Porta; Deana, Alessandro; Lima Leal, Cintia Raquel; Prates, Renato Araujo; Hamblin, Michael R.; Bussadori, Sandra Kalil

    2016-01-01

    This study intended to evaluate the effects of a papain-gel with a red-light absorbing pigment (methylene blue – MB) to mediate photodynamic therapy (PDT) against Streptococcus mutans biofilms. The PapaMBlue was compared with free MB to generate reactive oxygen species using fluorescence probes (SOSG and HPF). PDT (660-nm light) was carried out against S. mutans biofilms grown on either plastic dishes or on collagen membrane and assayed by CFU, live-dead staining using confocal microscopy, transmission electron microscopy and H&E staining for collagen films. Cytotoxicity and subcellular localization was studied in human fibroblasts. Sponges of bioabsorbable type I collagen membrane were exposed to papain based gel, irradiated with laser and analyzed about their integrity by ATR-FTIR. The PapaMBlue produced higher amounts of singlet oxygen and hydroxyl radicals than free MB, possibly due to better disaggregation of the dye in solution. The PapaMBlue antimicrobial effects on biofilms proved to be capable of reducing the S. mutans. Both MTT and PrestoBlue assays showed higher cell viability and metabolism scores in fibroblasts treated with PapaMBlue and MB, possibly due to stimulation of mitochondrial activity and that collagen triple helix is unaffected. The PapaMBlue is equally effective as MB in destroying S. mutans biofilms growing on plastic or collagen without affecting fibroblasts. PMID:27641507

  17. Cationic Methylene-Pyrene Isomers and Isomerization Pathways: Finite Temperature Theoretical Studies.

    PubMed

    Rapacioli, Mathias; Simon, Aude; Marshall, Charlotte C M; Cuny, Jérôme; Kokkin, Damian; Spiegelman, Fernand; Joblin, Christine

    2015-12-24

    This paper provides spectral characterizations of the two isomers of the 1-methylenepyrene cation, namely, the 1-pyrenemethylium and a pyrene-like isomer owing a tropylium cycle. Both are possible photodissociation products of the 1-methylpyrene cation and were proposed as potential contributors to the diffuse interstellar bands. In that respect, vibrational and electronic spectra are computed for the optimized structures at the density functional theory (DFT) and time-dependent (TD-)DFT levels. Finite temperature effects on these spectra are estimated from molecular dynamics simulations within the density functional-based tight-binding (DFTB) and TD-DFTB frameworks, these methods being first benchmarked against DFT and TD-DFT calculations. The computed spectra allow discrimination of the two isomers. When the temperature increases, bands are observed to redshift and merge. The isomerization mechanism is investigated with the metadynamics technique, a biased dynamics scheme allowing to probe reaction mechanisms with high energy barriers by investigating the free energy surface at various temperatures. Four pathways with similar barrier heights (3.5-4 eV) are found, showing that the interconversion process would only occur in interstellar clouds under photoactivation. The present study opens the way to simulations on larger methyl- and methylenePAHs of astrophysical interest and their experimental investigation. PMID:26600076

  18. A sensitive resveratrol assay with a simple probe methylene blue by resonance light scattering technique

    NASA Astrophysics Data System (ADS)

    Xiang, Haiyan; Dai, Kaijin; Luo, Qizhi; Duan, Wenjun; Xie, Yang

    2011-01-01

    A novel resonance light scattering (RLS) method was developed for the determination of resveratrol based on the interaction between resveratrol and methylene blue (MB). It was found that at pH 8.69, the weak RLS intensity of MB was remarkably enhanced by the addition of trace amount of resveratrol with the maximum peak located at 385.0 nm. Under the optimum conditions, a good linear relationship between the enhanced RLS intensities and the concentrations of resveratrol was obtained over the range of 2.0-14.0 μg ml -1 with the detection limit (3 σ) of 0.63 μg ml -1. The results of the analysis of resveratrol in synthetic samples and human urine are satisfactory, which showed it may provide a more sensitive, convenient, rapid and reproducible method for the detection of resveratrol, especially in biological and pharmaceutical field. In this work, the characteristics of RLS, absorption and fluorescence spectra of the resveratrol-MB system, the influencing factors and the optimum conditions of the reaction were investigated.

  19. Guava (Psidium guajava) leaf powder: novel adsorbent for removal of methylene blue from aqueous solutions.

    PubMed

    Ponnusami, V; Vikram, S; Srivastava, S N

    2008-03-21

    Batch sorption experiments were carried out using a novel adsorbent, guava leaf powder (GLP), for the removal of methylene blue (MB) from aqueous solutions. Potential of GLP for adsorption of MB from aqueous solution was found to be excellent. Effects of process parameters pH, adsorbent dosage, concentration, particle size and temperature were studied. Temperature-concentration interaction effect on dye uptake was studied and a quadratic model was proposed to predict dye uptake in terms of concentration, time and temperature. The model conforms closely to the experimental data. The model was used to find optimum temperature and concentration that result in maximum dye uptake. Langmuir model represent the experimental data well. Maximum dye uptake was found to be 295mg/g, indicating that GLP can be used as an excellent low-cost adsorbent. Pseudo-first-order, pseudo-second order and intraparticle diffusion models were tested. From experimental data it was found that adsorption of MB onto GLP follow pseudo second order kinetics. External diffusion and intraparticle diffusion play roles in adsorption process. Free energy of adsorption (DeltaG degrees ), enthalpy change (DeltaH degrees ) and entropy change (DeltaS degrees ) were calculated to predict the nature of adsorption. Adsorption in packed bed was also evaluated.

  20. Removal of basic dye (methylene blue) from wastewaters utilizing beer brewery waste.

    PubMed

    Tsai, Wen-Tien; Hsu, Hsin-Chieh; Su, Ting-Yi; Lin, Keng-Yu; Lin, Chien-Ming

    2008-06-15

    In the work, the beer brewery waste has been shown to be a low-cost adsorbent for the removal of basic dye from the aqueous solution as compared to its precursor (i.e., diatomite) based on its physical and chemical characterizations including surface area, pore volume, scanning electron microscopy (SEM), and non-mineral elemental analyses. The pore properties of this waste were significantly larger than those of its raw material, reflecting that the trapped organic matrices contained in the waste probably provided additional adsorption sites and/or adsorption area. The results of preliminary adsorption kinetics showed that the diatomite waste could be directly used as a potential adsorbent for removal of methylene blue on the basis of its adsorption-biosorption mechanisms. The adsorption parameters thus obtained from the pseudo-second-order model were in accordance with their pore properties. From the results of adsorption isotherm at 298 K and the applicability examinations in treating industrial wastewater containing basic dye, it was further found that the adsorption capacities of diatomite waste were superior to those of diatomite, which were also in good agreement with their corresponding physical properties. From the results mentioned above, it is feasible to utilize the food-processing waste for removing dye from the industrial dying wastewater.

  1. Biosorption of methylene blue from wastewater by an extraction residue of Salvia miltiorrhiza Bge.

    PubMed

    Zhao, Sunxiang; Zhou, Tongshui

    2016-11-01

    Efforts were made in this study to using an extraction residue of Salvia mitiorrziza Bge (SM), a widely utilized traditional Chinese medicine, as an effective biosorbent of methylene blue from polluted water. Batch experiments were carried out with original and chemical modification, particle size, dosage, solution pH, contact time, and initial concentration of the dye. Experimental data fit Langmuir isotherm and pseudo-second order kinetic best compared to other models applied in the study. Characterization of adsorption was determined by FT-IR, SEM and particle surface area measurement. The maximum monolayer biosorption capacity of raw SM is 100.0mg·g(-1). The citric acid and Na2CO3 modification can significantly enhance this value up to 161.29 and 178.57mg·g(-1), respectively. This investigation provides a novel approach for reutilizing the enormous quantity of Chinese herbal medicine wastes, which is significant since these dregs have brought out big environmental and heathy problems in the present China. PMID:27501030

  2. Designing metallic iron based water filters: Light from methylene blue discoloration.

    PubMed

    Btatkeu-K, B D; Tchatchueng, J B; Noubactep, C; Caré, S

    2016-01-15

    Available water filtration systems containing metallic iron (Fe(0) filters) are pragmatically designed. There is a lack of sound design criteria to exploit the full potential of Fe(0) filters. A science-based design relies on valuable information on processes within a Fe(0) filter, including chemical reactions, hydrodynamics and their relation to the performance of the filter. The aim of this study was to establish a simple method to evaluate the initial performance of Fe(0) filters. The differential adsorptive affinity of methylene blue (MB) onto sand and iron oxide is exploited to characterize the evolution of a Fe(0)/sand system using the pure sand system as operational reference. Five systems were investigated for more than 70 days: pure sand, pure Fe(0), Fe(0)/sand, Fe(0)/pumice and Fe(0)/sand/pumice. Individual systems were characterized by the extent of changes in pH value, iron breakthrough, MB breakthrough and hydraulic conductivity. Results showed that for MB discoloration (i) pure sand was the most efficient system, (ii) hybrid systems were more sustainable than the pure Fe(0) system, and (iii) the pores of used pumice are poorly interconnected. Characterizing the initial reactivity of Fe(0) filters using MB discoloration has introduced a powerful tool for the exploration of various aspects of filter design.

  3. Aggregation of methylene blue in frozen aqueous solutions studied by absorption spectroscopy.

    PubMed

    Heger, Dominik; Jirkovský, Jaromír; Klán, Petr

    2005-08-01

    The paper presents a qualitative as well as quantitative spectroscopic study of methylene blue (MB) aggregation that occurs upon freezing the aqueous solutions over a wide concentration range. The Gaussian curve analysis and the multivariate curve resolution-alternating least squares method were used to determine the number and concentration of chemical species responsible for the overlaying absorption visible spectra measured. The results show the extent of aggregation for the concentrations above 10(-7) mol L(-1), being dependent on the freezing rate and the initial concentration. While the local concentration of MB at the grain boundaries of polycrystalline ice increased by approximately 3 orders of magnitude upon fast freezing at 77 K compared to the liquid phase, the concentration raised at least by 6 orders of magnitude upon slow freezing at 243 K. Since enhancement of the local concentration of solutes plays an important role in (photo)chemical transformations in solid aqueous media, this work helps to understand how the initial conditions control the course of the process. The results are relevant in other interdisciplinary fields, such as environmental chemistry, cosmochemistry, or geochemistry.

  4. Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes.

    PubMed

    Szlachta, M; Wójtowicz, P

    2013-01-01

    This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m(2)/g, MWCNTs 358 m(2)/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal. PMID:24292474

  5. Photocatalytic Activity of W-Doped TiO2 Nanofibers for Methylene Blue Dye Degradation.

    PubMed

    Song, Yo-Seung; Cho, Nam-Ihn; Lee, Myung-Hyun; Kim, Bae-Yeon; Lee, Deuk Yong

    2016-02-01

    Photocatalytic degradation of methylene blue (MB) in water was examined using W-doped TiO2 nanofibers prepared by a sol-gel derived electrospinning and subsequent calcination for 4 h at 550 degrees C. Different concentrations of W dopant in the range of 0 to 8 mol% were synthesized to evaluate the effect of W concentration on the photocatalytic activity of TiO2. XRD results indicated that the undoped TiO2 is composed of anatase and rutile phases. The rutile phase was transformed to anatase phase completely with the W doping. Among W-TiO2 catalysts, the 2 mol% W-TiO2 catalyst showed the highest MB degradation rate. The degradation kinetic constant increased from 1.04 x 10(-3) min(-1) to 3.54 x 10(-3) min(-1) with the increase of W doping from 0 to 2 mol%, but decreased down to 1.77 x 10(-3) min(-1) when the W content was 8 mol%. It can be concluded that the degradation of MB under UV radiation was more efficient with W-TiO2 catalysts than with pure TiO2-

  6. Adsorption of methylene blue on low-cost adsorbents: a review.

    PubMed

    Rafatullah, Mohd; Sulaiman, Othman; Hashim, Rokiah; Ahmad, Anees

    2010-05-15

    In this article, the use of low-cost adsorbents for the removal of methylene blue (MB) from solution has been reviewed. Adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those which are not easily biodegradable. The removal of MB, as a pollutant, from waste waters of textile, paper, printing and other industries has been addressed by the researchers. Currently, a combination of biological treatment and adsorption on activated carbon is becoming more common for removal of dyes from wastewater. Although commercial activated carbon is a preferred adsorbent for color removal, its widespread use is restricted due to its relatively high cost which led to the researches on alternative non-conventional and low-cost adsorbents. The purpose of this review article is to organize the scattered available information on various aspects on a wide range of potentially low-cost adsorbents for MB removal. These include agricultural wastes, industrial solid wastes, biomass, clays minerals and zeolites. Agricultural waste materials being highly efficient, low cost and renewable source of biomass can be exploited for MB remediation. It is evident from a literature survey of about 185 recently published papers that low-cost adsorbents have demonstrated outstanding removal capabilities for MB. PMID:20044207

  7. Adsorption and Photocatalytic Degradation of Methylene Blue Using Potassium Polytitanate and Solar Simulator.

    PubMed

    Shahid, Mohammad; El Saliby, Ibrahim; McDonagh, Andrew; Chekli, Laura; Tijing, Leonard D; Kim, Jong-Ho; Shon, Ho Kyong

    2016-05-01

    Solar photocatalytic degradation of organic water pollutants can be used to degrade toxic organic pollutants in water. In this study, potassium titanate nanofibres were synthesized by an aqueous peroxide route at high pH and examined as photocatalysts for photodegradation of methylene blue (MB) using a solar simulator. Initially, MB was adsorbed on the surface of potassium polytitanates to achieve adsorption equilibrium before the photocatalysts were illuminated using solar simulator. The results showed that potassium polytitanate nanofibres were effective adsorbents of MB and also facilitated its photocatalytic degradation. Sulphate ion evolution during photocatalysis confirmed that some mineralisation occurred and hence photo-oxidative degradation of MB took place. The optimum operational conditions for the photocatalytic degradation of MB were found at 0.05 g/L of photocatalyst load, 10 mg/L MB and pH 7. The stability and regeneration of the photocatalyst specimen was also studied for 3 degradation cycles using adsorption/photocatalysis model. Morphological structure analysis of potassium titanate showed nanocrystallines structure of longitudinally-oriented isolated fibre with a length up to several micrometres with diameters ranging from 10 to 20 nanometres. PMID:27483755

  8. Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars.

    PubMed

    Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong

    2016-01-01

    Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB.

  9. Decolorization of methylene blue in aqueous suspensions of gold nanoparticles using parallel nanosecond pulsed laser.

    PubMed

    Zong, Yan P; Liu, Xian H; Du, Xi W; Lu, Yi R; Wang, Mei Y; Wang, Guang Y

    2013-01-01

    Using 532 nm parallel nanosecond pulsed laser, the decolorization of methylene blue (MB) in aqueous suspensions of gold nanoparticles (GNPs) was studied. The effects of various experimental parameters, such as irradiation time, laser energy, and initial MB concentration on the decolorization rate were investigated. Experiments using real samples of textile dyeing wastewater were also carried out to examine the effectiveness of the method in more complex samples. From the results, the following conclusions may be drawn: (i) Under the optimum conditions (pH 7.19, 135 mJ laser energy, 4 mg/L MB concentration, and 11.6 mg/L GNP concentration), the rate of MB decolorization could reach 94% in 15 min. The decolorization follows pseudo-first-order kinetics; (ii) The amount of MB decreased rapidly during the decolorization. No intermediates of the decolorization could be detected by high-performance liquid chromatography. These observations indicate that MB was decolorized through a very rapid degradation mechanism; (iii) The rate of MB decolorization increased with the increase in laser energy (at laser energies of 0 to 135 mJ); and, (iv) The efficient decolorization of MB in real samples of textile dyeing wastewater was achieved at a decolorization rate of about 85% in 15 min.

  10. Porphyrin-Alkaline Earth MOFs with the Highest Adsorption Capacity for Methylene Blue.

    PubMed

    Hou, Yuxia; Sun, Junshan; Zhang, Daopeng; Qi, Dongdong; Jiang, Jianzhuang

    2016-04-25

    A series of four porphyrin-alkaline earth metal- organic frameworks [Mg(HDCPP)2 (DMF)2 ]n ⋅(H2 O)7 n (1), [Ca(HDCPP)2 (H2 O)2 ]n (DMF)1.5 n (2), [Sr(DCPP)(H2 O)(DMA)]n (3), and [Ba(DCPP)(H2 O)(DMA)]n (4) was isolated for the first time from solvothermal reaction between metal-free 5,15-di(4- carboxyphenyl)porphyrin (H2 DCPP) and alkaline earth ions. Single-crystal X-ray diffraction analysis reveals the 2D and 3D supramolecular network with periodic nanosized porosity for 1/2 and 3/4, respectively. The whole series of MOFs, in particular, compounds 1 and 2 with intrinsic low molecular formula weight, exhibit superior adsorption performance for methylene blue (MB) with excellent capture capacity as represented by the thus far highest adsorption amount of 952 mg g(-1) for 2 and good selectivity, opening a new way for the potential application of the main group metal-based MOFs. PMID:27002679

  11. Effects of the oxidation degree of graphene oxide on the adsorption of methylene blue.

    PubMed

    Yan, Han; Tao, Xue; Yang, Zhen; Li, Kun; Yang, Hu; Li, Aimin; Cheng, Rongshi

    2014-03-15

    In this current work, a series of graphene oxides (GO) with different oxidation degrees (OD) was prepared using Hummer method. Fundamental adsorption behavior of the GO series for removal of methylene blue (MB) from aqueous solutions has been studied. The GO series shows an overall fast and pH-independent MB adsorption, which is even capable of removing trace levels of dye completely from very dilute solutions. Furthermore, the effects of the oxidation degree (OD) on MB adsorption behavior have been investigated systematically, indicating that the dye uptakes of GO exponentially increase with the increase of OD. Further study on the adsorption mechanism shows that adsorption behavior of GO would change from a Freundlich-type to a Langmuir-type adsorption as the OD increases. It may be due to both the enhanced exfoliation degree of the carbon planes in graphite caused by oxidation and the production of more active adsorption sites. The binding features of the MB loaded GO gradually change from MB molecule parallel stacking on graphite plane through hydrophobic π-π interaction to vertical standing via electrostatic interaction with increasing OD, resulting in a significant improvement of MB uptakes. In addition, the adsorption capacity of the regenerated GO has little loss until four cycles. PMID:24491443

  12. Designing metallic iron based water filters: Light from methylene blue discoloration.

    PubMed

    Btatkeu-K, B D; Tchatchueng, J B; Noubactep, C; Caré, S

    2016-01-15

    Available water filtration systems containing metallic iron (Fe(0) filters) are pragmatically designed. There is a lack of sound design criteria to exploit the full potential of Fe(0) filters. A science-based design relies on valuable information on processes within a Fe(0) filter, including chemical reactions, hydrodynamics and their relation to the performance of the filter. The aim of this study was to establish a simple method to evaluate the initial performance of Fe(0) filters. The differential adsorptive affinity of methylene blue (MB) onto sand and iron oxide is exploited to characterize the evolution of a Fe(0)/sand system using the pure sand system as operational reference. Five systems were investigated for more than 70 days: pure sand, pure Fe(0), Fe(0)/sand, Fe(0)/pumice and Fe(0)/sand/pumice. Individual systems were characterized by the extent of changes in pH value, iron breakthrough, MB breakthrough and hydraulic conductivity. Results showed that for MB discoloration (i) pure sand was the most efficient system, (ii) hybrid systems were more sustainable than the pure Fe(0) system, and (iii) the pores of used pumice are poorly interconnected. Characterizing the initial reactivity of Fe(0) filters using MB discoloration has introduced a powerful tool for the exploration of various aspects of filter design. PMID:26518123

  13. Methylene blue biosorption by pericarp of corn, alfalfa, and agave bagasse wastes.

    PubMed

    Rosas-Castor, José M; Garza-González, María T; García-Reyes, Refugio B; Soto-Regalado, Eduardo; Cerino-Córdova, Felipe J; García-González, Alcione; Loredo-Medrano, José A

    2014-01-01

    The presence of dyes in effluent is a matter of concern due to their toxicologic and aesthetical effects. In this research, locally available agro-industrial wastes (Zea mays pericarp, ZMP; Agave tequilana bagasse, ATB; and Medicago sativa waste, MSW) were used as alternative low-cost adsorbents for the removal of methylene blue (MB) from aqueous solutions. The adsorbents were characterized physically and chemically by Fourier transform infrared, scanning electron microscopy, potentiometric titrations, and N2 physisorption. MB adsorption experiments were carried out in batch systems and experimental data were used to calculate the adsorption isotherm model parameters (Langmuir, Freundlich, and Temkin) and the adsorption kinetic model parameters (pseudo-first- and pseudo-second-order models). MB-loaded biosorbents were desorbed with deionized water, ethanol (10% and 50% v/v), hydrochloric acid (0.01 and 0.05 N), and sodium hydroxide (0.1 N) at room temperature, and the best eluent was used in various adsorption-desorption cycles. The selected agricultural wastes can be considered as promising adsorbents for dye uptake from water since they exhibit considerable MB adsorption capacity (MSW 202.6 mg g(-1), ATB 156.2mg g(-1), and ZMP 110.9mg g(-1)), but it is lower than that reported for activated carbon; however, the biosorbents show higher adsorption rate than powdered activated carbon. Furthermore, the adsorbents can be economically regenerated with HCl solutions and reused for seven adsorption-desorption cycles.

  14. Methylene Blue Modulates β-Secretase, Reverses Cerebral Amyloidosis, and Improves Cognition in Transgenic Mice*

    PubMed Central

    Mori, Takashi; Koyama, Naoki; Segawa, Tatsuya; Maeda, Masahiro; Maruyama, Nobuhiro; Kinoshita, Noriaki; Hou, Huayan; Tan, Jun; Town, Terrence

    2014-01-01

    Amyloid precursor protein (APP) proteolysis is required for production of amyloid-β (Aβ) peptides that comprise β-amyloid plaques in the brains of patients with Alzheimer disease (AD). Here, we tested whether the experimental agent methylene blue (MB), used for treatment of methemoglobinemia, might improve AD-like pathology and behavioral deficits. We orally administered MB to the aged transgenic PSAPP mouse model of cerebral amyloidosis and evaluated cognitive function and cerebral amyloid pathology. Beginning at 15 months of age, animals were gavaged with MB (3 mg/kg) or vehicle once daily for 3 months. MB treatment significantly prevented transgene-associated behavioral impairment, including hyperactivity, decreased object recognition, and defective spatial working and reference memory, but it did not alter nontransgenic mouse behavior. Moreover, brain parenchymal and cerebral vascular β-amyloid deposits as well as levels of various Aβ species, including oligomers, were mitigated in MB-treated PSAPP mice. These effects occurred with inhibition of amyloidogenic APP proteolysis. Specifically, β-carboxyl-terminal APP fragment and β-site APP cleaving enzyme 1 protein expression and activity were attenuated. Additionally, treatment of Chinese hamster ovary cells overexpressing human wild-type APP with MB significantly decreased Aβ production and amyloidogenic APP proteolysis. These results underscore the potential for oral MB treatment against AD-related cerebral amyloidosis by modulating the amyloidogenic pathway. PMID:25157105

  15. Photocatalytic Activity of W-Doped TiO2 Nanofibers for Methylene Blue Dye Degradation.

    PubMed

    Song, Yo-Seung; Cho, Nam-Ihn; Lee, Myung-Hyun; Kim, Bae-Yeon; Lee, Deuk Yong

    2016-02-01

    Photocatalytic degradation of methylene blue (MB) in water was examined using W-doped TiO2 nanofibers prepared by a sol-gel derived electrospinning and subsequent calcination for 4 h at 550 degrees C. Different concentrations of W dopant in the range of 0 to 8 mol% were synthesized to evaluate the effect of W concentration on the photocatalytic activity of TiO2. XRD results indicated that the undoped TiO2 is composed of anatase and rutile phases. The rutile phase was transformed to anatase phase completely with the W doping. Among W-TiO2 catalysts, the 2 mol% W-TiO2 catalyst showed the highest MB degradation rate. The degradation kinetic constant increased from 1.04 x 10(-3) min(-1) to 3.54 x 10(-3) min(-1) with the increase of W doping from 0 to 2 mol%, but decreased down to 1.77 x 10(-3) min(-1) when the W content was 8 mol%. It can be concluded that the degradation of MB under UV radiation was more efficient with W-TiO2 catalysts than with pure TiO2- PMID:27433681

  16. Preparation and characterization of methylene blue nanoparticles for Alzheimer's disease and other tauopathies.

    PubMed

    Jinwal, Umesh K; Groshev, Anastasia; Zhang, Juan; Grover, Aditya; Sutariya, Vijaykumar B

    2014-01-01

    Methylene blue (MB) has been shown to slow down the progression of the Alzheimer's disease (AD) and other tauopathies; however distribution of MB into the brain is limited due its high hydrophilicity. In this study, we aimed to prepare novel hydrophobic glutathione coated PLGA nanoparticles to improve bioavailability of MB in the brain. Glutathione coated poly-(lactide-co-glycolide) (PLGA-b-PEG) nanoparticles (NPs) were prepared and tested in two different cell culture models of AD expressing microtubule associated protein tau (tau). The NPs showed a particle size averaging 136.5±4.4nm, which is suitable for the blood brain barrier (BBB) permeation. The in vitro release profile of the NPs exhibited no initial burst release and showed sustained drug release for up to 144 hours. Interestingly, treatment of newly formulated MB-NPs showed a potent reduction in both endogenous and over expressed tau protein levels in human neuroblastoma SHSY-5Y cells expressing endogenous tau and transfected HeLa cells over-expressing tau protein, respectively. Furthermore, in vitro BBB Transwell™ study showed significantly higher permeation of MB-NP compared to the MB solution through the co culture of rat brain endothelial 4 (RBE4) and C6 astrocytoma cells (p<0.05). The proposed MB loaded nanoparticles could provide a more effective treatment option for AD and many other related disorders.

  17. Methylene blue photodynamic therapy in rats' wound healing: 21 days follow-up

    NASA Astrophysics Data System (ADS)

    Carneiro, Vanda Sanderana Macêdo; Catao, Maria Helena Chaves de Vasconcelos; Menezes, Rebeca Ferraz; Araújo, Natália Costa; Gerbi, Marleny Elizabeth Martinez

    2015-06-01

    The experimental evaluated the photodynamic therapy (PDT) in wound healing. It used 60 male rats, making two circular wounds at each animal. They were treated at 48hs intervals, with methylene blue (MB), low level laser treatment (LLLT) or both, thus resulting in PDT. The wounds were observed 01, 03, 07, 14 and 21 days after and then processed and subjected to HE staining to analyze granulation tissue, necrosis, epithelialization and collagen. After day 1, wounds treated with MB showed necrosis less intense than other groups, and the PDT group showed more intense granulation tissue. At day 3, reepithelialization was absent for half of injuries in the PDT group, and this group was also with lower collagen. However, at day 7, this same group presented reepithelialization more advanced than control group, which did not happen with those treated with MB or LLLT (p = 0.015). The results allow us to conclude that PDT difficulted reepithelization at 7th day and interfered in standard healing. However, when used separately, MB and LLLT interfered significantly compared to the control group, which did not happened to the PDT group. There was no significant difference between the treatment groups in other analysed times.

  18. The Coriolis Interaction between the nu(9) and nu(7) Fundamental Bands of Methylene Fluoride.

    PubMed

    Goh; Tan; Ong; Teo

    2000-06-01

    The infrared spectrum of the nu(7) and nu(9) bands of methylene fluoride-d(2) (CD(2)F(2)) has been recorded with an unapodized resolution of 0.0024 cm(-1) in the frequency range of 940-1030 cm(-1) using the Fourier transform technique. A weak b-type Coriolis interaction term was found to couple these two vibrational states with band centers about 42 cm(-1) apart. By fitting a total of 1031 infrared transitions of both nu(7) and nu(9) with a standard deviation of 0.0011 cm(-1) using a Watson's A-reduced Hamiltonian in the I(r) representation with the inclusion of a b-type Coriolis resonance term, two sets of rovibrational constants for nu(7) = 1 and nu(9) = 1 states up to sextic order were derived. The nu(7) band is C type, while the nu(9) band is A type with band centers at 961.8958 +/- 0.0005 and 1003.7421 +/- 0.0001 cm(-1), respectively. Copyright 2000 Academic Press.

  19. Enzymatic Hydroxylation of an Unactivated Methylene C–H Bond Guided by Molecular Dynamics Simulations

    PubMed Central

    Narayan, Alison R. H.; Jiménez-Osés, Gonzalo; Liu, Peng; Negretti, Solymar; Zhao, Wanxiang; Gilbert, Michael M.; Ramabhadran, Raghunath O.; Yang, Yun-Fang; Furan, Lawrence R.; Li, Zhe; Podust, Larissa M.; Montgomery, John; Houk, K. N.; Sherman, David H.

    2015-01-01

    The hallmark of enzymes from secondary metabolic pathways is the pairing of powerful reactivity with exquisite site selectivity. The application of these biocatalytic tools in organic synthesis, however, remains under-utilized due to limitations in substrate scope and scalability. Here we report the reactivity of a monooxygenase (PikC) from the pikromycin pathway is modified through computationally-guided protein and substrate engineering, and applied to the oxidation of unactivated methylene C-H bonds. Molecular dynamics and quantum mechanical calculations were employed to develop a predictive model for substrate scope, site selectivity, and stereoselectivity of PikC mediated C-H oxidation. A suite of menthol derivatives was screened computationally and evaluated through in vitro reactions where each substrate adhered to the predicted models for selectivity and conversion to product. This platform was also expanded beyond menthol-based substrates to the selective hydroxylation of a variety of substrate cores ranging from cyclic to fused bicyclic and bridged bicyclic compounds. PMID:26201742

  20. New Twist on an Old Favorite: Gentian Violet and Methylene Blue Antibacterial Foams

    PubMed Central

    Edwards, Karen

    2016-01-01

    Significance: Absorptive antibacterial dressings that assist in controlling bioburden without risks of cytotoxicity or residual absorption can be effectively used for prolonged periods throughout the wound healing continuum. Recent Advances: Until recently, gentian violet and methylene blue (GV/MB) antibacterial dressings have been commercially available only in polyvinyl alcohol (PVA) foam; polyurethane (PU) foam bonded with GV and MB with thin film backing is now commercially available. GV/MB PU foam does not require hydration or a necessary secondary dressing. GV/MB PVA and PU foam dressings were recently granted FDA clearance as antibacterial dressings, as opposed to bacteriostatic dressings as previously classified. Within the class of antibacterial dressings, GV/MB foam dressings are of lower cost alternative to silver- or iodine-based antibacterial dressings with no risk of absorption of any of the foam components into the tissues. Critical Issues: Control of wound bioburden levels by antibacterial agents and absorption of excess exudate are crucial in preventing infections that drastically increase the price of wound care. Use of GV/MB dressings may improve wound healing outcomes and decrease overall costs through super absorption, promotion of autolytic debridement, bioburden reduction, ease of use, and decreased dressing change frequency. Future Directions: Evolution in resistant bacterial strains will drive continual changes in advanced wound care products. Demand will increase for economically priced, versatile wound care dressings that assist in debridement, maintain a moist wound environment, absorb and trap bacterial debris, and decrease dressing change frequency. PMID:26858911

  1. Facile fabrication of magnetic carboxymethyl starch/poly(vinyl alcohol) composite gel for methylene blue removal.

    PubMed

    Gong, Guisheng; Zhang, Faai; Cheng, Zehong; Zhou, Li

    2015-11-01

    This study presents a simple method to fabricate magnetic carboxymethyl starch/poly(vinyl alcohol) (mCMS/PVA) composite gel. The obtained mCMS/PVA was characterized by Fourier transform infrared (FTIR) spectra, vibrating-sample magnetometer (VSM) and scanning electron microscopy (SEM) measurements. The application of mCMS/PVA as an adsorbent for removal of cationic methylene blue (MB) dye from water was investigated. Benefiting from the combined merits of carboxymethyl starch and magnetic gel, the mCMS/PVA simultaneously exhibited excellent adsorption property toward MB and convenient magnetic separation capability. The effects of initial dye concentration, contact time, pH and ionic strength on the adsorption performance of mCMS/PVA adsorbent were investigated systematically. The adsorption process of mCMS/PVA for MB fitted pseudo-second-order model and Freundlich isotherm. Moreover, desorption experiments revealed that the mCMS/PVA adsorbent could be well regenerated in ethanol solution without obvious compromise of removal efficiency even after eight cycles of desorption/adsorption. Considering the facile fabrication process and robust adsorption performance, the mCMS/PVA composite gel has great potential as a low cost adsorbent for environmental decontamination.

  2. Adsorption of Methylene Blue from Aqueous Solutions by Polyvinyl Alcohol/Graphene Oxide Composites.

    PubMed

    Yang, Xiaoxia; Li, Yanhui; Du, Qiuju; Wang, Xiaohui; Hu, Song; Chen, Long; Wang, Zonghua; Xia, Yanzhi; Xia, Linhua

    2016-02-01

    As a new member of the carbon family, graphene oxide (GO) has shown excellent adsorption ability to micro-pollutants in aqueous solutions. However, its tiny size makes it difficult to be removed from aqueous solutions using the conventional separation methods, which limits its practical application in the environmental protection. In this study, polyvinyl alcohol (PVA) was used as carrier immobilizing GO, and novel PVA/GO composites were prepared. The morphology and physicochemical properties of the composites were characterized by SEM, FTIR and TGA analysis. The adsorption properties of methylene blue (MB) onto the composites were studied through investigating the experimental parameters such as solution pH, adsorbent dosage, contact time and temperature. The isotherm data were analyzed using the Langmuir, Freundlich and Dubinin-Radushkevich models. The calculated maximum adsorption capacity reached 476.2 mg/g at 50% GO content. The pseudo-first-order kinetic, pseudo-second-order kinetic and intra-particle diffusion models were used to explore the adsorption kinetics. The results showed that the dynamic data were fitted to the pseudo-second-order kinetic model. PMID:27433669

  3. Sorption of methylene blue on treated agricultural adsorbents: equilibrium and kinetic studies

    NASA Astrophysics Data System (ADS)

    Tiwari, D. P.; Singh, S. K.; Sharma, Neetu

    2015-03-01

    Agricultural adsorbents are reported to have a remarkable performance for adsorption of dyes. In the present study, formaldehyde and sulphuric acid treated two agricultural adsorbents; potato peel and neem bark are used to adsorb methylene blue. On the whole, the acid-treated adsorbents are investigated to have high sorption efficiency compared to HCHO treated adsorbents. The percentage removal efficiency of H2SO4 treated potato peel (APP) increases considerably high from 75 to 100 % with increase in adsorbent dose, whereas the removal efficiency of H2SO4 treated neem bark (ANB) is found to be 98 % after adding the first dose only. The monolayer sorption behaviour of HCHO treated potato peel (PP) and APP is well defined by Langmuir, whereas the chemisorptions behaviour of HCHO treated neem bark (NB) and ANB is suggested by Temkin's isotherm model. The maximum adsorption capacity measured is highest in ANB followed by NB, PP and APP with the values of 1000, 90, 47.62 and 40.0 mg/g, respectively. The pseudo-second-order kinetic model fitted well with the observed data of all the four adsorbents. The results obtained reveal that NB and ANB both are good adsorbents compared to PP and APP.

  4. Effects of ionic strength on the antimicrobial photodynamic efficiency of methylene blue.

    PubMed

    Núñez, Silvia Cristina; Garcez, Aguinaldo Silva; Kato, Ilka Tiemy; Yoshimura, Tania Mateus; Gomes, Laércio; Baptista, Maurício Silva; Ribeiro, Martha Simões

    2014-03-01

    Antimicrobial photodynamic therapy (APDT) may become a useful clinical tool to treat microbial infections, and methylene blue (MB) is a well-known photosensitizer constantly employed in APDT studies, and although MB presents good efficiency in antimicrobial studies, some of the MB photochemical characteristics still have to be evaluated in terms of APDT. This work aimed to evaluate the role of MB solvent's ionic strength regarding dimerization, photochemistry, and photodynamic antimicrobial efficiency. Microbiological survival fraction assays on Escherichia coli were employed to verify the solution's influence on MB antimicrobial activity. MB was evaluated in deionized water and 0.9% saline solution through optical absorption spectroscopy; the solutions were also analysed via dissolved oxygen availability and reactive oxygen species (ROS) production. Our results show that bacterial reduction was increased in deionized water. Also we demonstrated that saline solution presents less oxygen availability than water, the dimer/monomer ratio for MB in saline is smaller than in water and MB presented a higher production of ROS in water than in 0.9% saline. Together, our results indicate the importance of the ionic strength in the photodynamic effectiveness and point out that this variable must be taken into account to design antimicrobial studies and to evaluate similar studies that might present conflicting results.

  5. Pump-probe optical coherence tomography using microencapsulated methylene blue as a contrast agent (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kim, Wihan; Zebrowski, Erin; Lopez, Hazel C.; Applegate, Brian E.; Charoenphol, Phapanin; Jo, Javier A.

    2016-03-01

    Molecular contrast imaging can target specific molecules or receptors to provide detailed information on the local biochemistry and yield enhanced visualization of pathological and physiological processes. When paired with Optical Coherence Tomography (OCT) it can simultaneously supply the morphological context for the molecular information. We recently demonstrated in vivo molecular contrast imaging of methylene blue (MB) using a 663 nm diode laser as a pump in a Pump-Probe OCT (PPOCT) system. The simple addition of a dichroic mirror in the sample arm enabled PPOCT imaging with a typical 830-nm band spectral-domain OCT system. Here we report on the development of a microencapsulated MB contrast agent. The poly lactic-co-glycolic acid (PLGA) microspheres loaded with MB offer several advantages over bare MB. The microsphere encapsulation improves the PPOCT signal both by enhancing the scattering and preventing the reduction of MB to leucomethylene blue. The surface of the microsphere can readily be functionalized to enable active targeting of the contrast agent without modifying the excited state dynamics of MB that enable PPOCT imaging. Both MB and PLGA are used clinically. PLGA is FDA approved and used in drug delivery and tissue engineering applications. 2.5 μm diameter microspheres were synthesized with an inner core containing 0.01% (w/v) aqueous MB. As an initial demonstration the MB microspheres were imaged in a 100 μm diameter capillary tube submerged in a 1% intralipid emulsion.

  6. Effects of methylene blue in acute lung injury induced by oleic acid in rats

    PubMed Central

    Cassiano Silveira, Ana Paula; Vento, Daniella Alves; Albuquerque, Agnes Afrodite Sumarelli; Celotto, Andrea Carla; Tefé-Silva, Cristiane; Ramos, Simone Gusmão; Rubens de Nadai, Tales; Rodrigues, Alfredo José; Poli-Neto, Omero Benedicto

    2016-01-01

    Background In acute lung injury (ALI), rupture of the alveolar-capillary barrier determines the protein-rich fluid influx into alveolar spaces. Previous studies have reported that methylene blue (MB) attenuates such injuries. This investigation was carried out to study the MB effects in pulmonary capillary permeability. Methods Wistar rats were divided into five groups: (I) Sham: saline bolus; (II) MB, MB infusion for 2 h; (III) oleic acid (OA), OA bolus; (IV) MB/OA, MB infusion for 2 h, and at 5 min after from the beginning, concurrently with an OA bolus; and (V) OA/MB, OA bolus, and after 2 h, MB infusion for 2 h. After 4 h, blood, bronchoalveolar lavage (BAL), and lung tissue were collected from all groups for analysis of plasma and tissue nitric oxide, calculation of the wet weight to dry weight ratio (WW/DW), and histological examination of lung tissue. Statistical analysis was performed using nonparametric test. Results Although favourable trends have been observed for permeability improvement parameters (WW/WD and protein), the results were not statistically significant. However, histological analysis of lung tissue showed reduced lesion areas in both pre- and post-treatment groups. Conclusions The data collected using this experimental model was favourable only through macroscopic and histological analysis. These observations are valid for both MB infusions before or after induction of ALI. PMID:26855944

  7. Vibrational studies on (E)-1-((pyridine-2-yl)methylene)semicarbazide using experimental and theoretical method

    NASA Astrophysics Data System (ADS)

    Subashchandrabose, S.; Ramesh Babu, N.; Saleem, H.; Syed Ali Padusha, M.

    2015-08-01

    The (E)-1-((pyridine-2-yl)methylene)semicarbazide (PMSC) was synthesized. The experimental and theoretical study on molecular structure and vibrational spectra were carried out. The FT-IR (400-4000 cm-1), FT-Raman (50-3500 cm-1) and UV-Vis (200-500 nm) spectra of PMSC were recorded. The geometric structure, conformational analysis, vibrational wavenumbers of PMSC in the ground state have been calculated using B3LYP method of 6-311++G(d,p) basis set. The complete vibrational assignments were made on the basis of TED, calculated by SQM method. The Non-linear optical activity was measured by means of first order hyperpolarizability calculation and π-electrons of conjugative bond in the molecule. The intra-molecular charge transfer, mode hyperconjugative interaction and molecular stabilization energies were calculated. The band gap energies between occupied and unoccupied molecular orbitals were analyzed; it proposes lesser band gap with more reactivity. To understand the electronic properties of this molecule the Mulliken charges were also calculated.

  8. Heterogeneous photodegradation of methylene blue with iron and tea or coffee polyphenols in aqueous solutions.

    PubMed

    Morikawa, Claudio Kendi; Shinohara, Makoto

    2016-01-01

    Recently, we developed two new Fenton catalysts using iron (Fe) and spent tea leaves or coffee grounds as raw material. In this study, Fe-to-tea or Fe-to-coffee polyphenol complexes were successfully tested as heterogeneous photo-Fenton catalysts. The photodegradation efficiency of methylene blue solutions with Fe-to-polyphenol complexes was higher than that of homogeneous iron salts in the photo-Fenton process. Furthermore, the tested Fe-to-polyphenol complexes could be reused by simply adding H2O2 to the solutions. After three sequential additions of H2O2, the conventional catalysts FeCl2·4H2O and FeCl3 removed only 16.6% and 53.6% of the dye, while the catalysts made using spent coffee grounds and tea leaves removed 94.4% and 96.0% of the dye, respectively. These results showed that the complexes formed between Fe and chlorogenic acid, caffeic acid, gallic acid and catechin, which are the main polyphenols in tea and coffee, can be used to improve the photo-Fenton process. PMID:27120642

  9. Twenty years of vasoplegic syndrome treatment in heart surgery. Methylene blue revised

    PubMed Central

    Evora, Paulo Roberto Barbosa; Alves, Lafaiete; Ferreira, Cesar Augusto; Menardi, Antônio Carlos; Bassetto, Solange; Rodrigues, Alfredo José; Scorzoni, Adilson; Vicente, Walter Vilella de Andrade

    2015-01-01

    Objective This study was conducted to reassess the concepts established over the past 20 years, in particular in the last 5 years, about the use of methylene blue in the treatment of vasoplegic syndrome in cardiac surgery. Methods A wide literature review was carried out using the data extracted from: MEDLINE, SCOPUS and ISI WEB OF SCIENCE. Results The reassessed and reaffirmed concepts were 1) MB is safe in the recommended doses (the lethal dose is 40 mg/kg); 2) MB does not cause endothelial dysfunction; 3) The MB effect appears in cases of NO up-regulation; 4) MB is not a vasoconstrictor, by blocking the cGMP pathway it releases the cAMP pathway, facilitating the norepinephrine vasoconstrictor effect; 5) The most used dosage is 2 mg/kg as IV bolus, followed by the same continuous infusion because plasma concentrations sharply decrease in the first 40 minutes; and 6) There is a possible "window of opportunity" for MB's effectiveness. In the last five years, major challenges were: 1) Observations about side effects; 2) The need for prophylactic and therapeutic guidelines, and; 3) The need for the establishment of the MB therapeutic window in humans. Conclusion MB action to treat vasoplegic syndrome is time-dependent. Therefore, the great challenge is the need, for the establishment the MB therapeutic window in humans. This would be the first step towards a systematic guideline to be followed by possible multicenter studies. PMID:25859872

  10. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles

    PubMed Central

    Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

    2015-01-01

    Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R2 values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R2 values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents. PMID:26843977

  11. Papain gel containing methylene blue for simultaneous caries removal and antimicrobial photoinactivation against Streptococcus mutans biofilms.

    PubMed

    Silva, Zenildo Santos; Huang, Ying-Ying; de Freitas, Lucas Freitas; França, Cristiane Miranda; Botta, Sergio Brossi; Ana, Patrícia Aparecida; Mesquita-Ferrari, Raquel Agnelli; Santos Fernandes, Kristianne Porta; Deana, Alessandro; Lima Leal, Cintia Raquel; Prates, Renato Araujo; Hamblin, Michael R; Bussadori, Sandra Kalil

    2016-01-01

    This study intended to evaluate the effects of a papain-gel with a red-light absorbing pigment (methylene blue - MB) to mediate photodynamic therapy (PDT) against Streptococcus mutans biofilms. The PapaMBlue was compared with free MB to generate reactive oxygen species using fluorescence probes (SOSG and HPF). PDT (660-nm light) was carried out against S. mutans biofilms grown on either plastic dishes or on collagen membrane and assayed by CFU, live-dead staining using confocal microscopy, transmission electron microscopy and H&E staining for collagen films. Cytotoxicity and subcellular localization was studied in human fibroblasts. Sponges of bioabsorbable type I collagen membrane were exposed to papain based gel, irradiated with laser and analyzed about their integrity by ATR-FTIR. The PapaMBlue produced higher amounts of singlet oxygen and hydroxyl radicals than free MB, possibly due to better disaggregation of the dye in solution. The PapaMBlue antimicrobial effects on biofilms proved to be capable of reducing the S. mutans. Both MTT and PrestoBlue assays showed higher cell viability and metabolism scores in fibroblasts treated with PapaMBlue and MB, possibly due to stimulation of mitochondrial activity and that collagen triple helix is unaffected. The PapaMBlue is equally effective as MB in destroying S. mutans biofilms growing on plastic or collagen without affecting fibroblasts. PMID:27641507

  12. [Adsorption behavior of copper ion and methylene blue on citric acid- esterified wheat straw].

    PubMed

    Sun, Jin; Zhong, Ke-Ding; Feng, Min; Liu, Xing-Yan; Gong, Ren-Min

    2008-03-01

    A cationic adsorbent with carboxyl groups derived from citric acid- esterified wheat straw (EWS) was prepared by the method of solid phase preparation, and a batch experiment was conducted to study the adsorption behaviors of Cu (II) and methylene blue (MB) in aqueous solution on the EWS under conditions of different initial pH, adsorbent dosage, adsorbate concentration, and contact time. The results showed that the maximum adsorption of Cu (II) and MB was obtained when the initial solution pH was > or = 4.0. 96% of Cu (II) in 100 mg x L(-1) Cu solution and 99% of MB in 250 mg x L(-1) dye solution could be removed by > or = 2.0 g x L(-1) of EWS. The adsorption of Cu (II) and MB fitted the Langmuir sorption isothermal model. The maximum removal capacity (Qm) of EWS was 79.37 mg x g(-1) for Cu (II) and 312.50 mg x g(-1) for MB, and the adsorption equilibrium of Cu (II) and MB was reached within 75 min and 5 h, respectively. The adsorption processes of Cu (II) and MB could be described by pseudo-first order and pseudo-second order kinetic functions, respectively.

  13. Photosensitization of Aggregatibacter actinomycetemcomitans with methylene blue: a microbiological and spectroscopic study

    NASA Astrophysics Data System (ADS)

    Yamada Júnior, Aécio M.; Prates, Renato A.; Cai, Silvana; Ribeiro, Martha S.

    2008-03-01

    The aim of this study was to determinate the efficiency of methylene blue (MB) to kill cultures of Aggregatibacter actinomycetemcomitans under red light and to investigate MB photobleaching by optical absorption spectroscopy. Bacteria were diluted in aqueous solution, putted in glass tubes and distributed in 5 groups: (L-MB-) control group; (L+MB-) laser alone by 5min; (L-MB+) MB alone through 5min; (3L+MB+) MB+laser 3min; (5L+MB+) MB+laser 5min. Laser parameters were P=30mW, λ=660nm, E=9J in 5min and E=5.4J in 3min. The samples were diluted and bacterial colonies were counted and converted into colony forming units (CFU). Absorption spectra of the MB-stained bacterial suspension and photosensitized bacterial suspension were obtained. Groups L-MB-, L+MB-, and L-MB+ did not show a decrease in CFU/mL. L+MB+ groups showed a significant decrease in CFU/mL but no statistically significant differences were observed between 3min and 5min. Spectroscopy showed that MB is photodegraded after irradiation and that dimer species are more notably consumed than monomeric species. These results suggest that MB is a suitable photosensitizer to reduce A. actinomycetemcomitans, and that 3min of irradiation are enough to produce a significant effect. Due to the spectral changes observed on MB solution after irradiation a type I mechanism may be involved.

  14. Methylene blue delays cellular senescence and enhances key mitochondrial biochemical pathways.

    PubMed

    Atamna, Hani; Nguyen, Andy; Schultz, Carla; Boyle, Kathleen; Newberry, Justin; Kato, Hiroyuki; Ames, Bruce N

    2008-03-01

    Methylene blue (MB) has been used clinically for about a century to treat numerous ailments. We show that MB and other diaminophenothiazines extend the life span of human IMR90 fibroblasts in tissue culture by >20 population doubling (PDLs). MB delays senescence at nM levels in IMR90 by enhancing mitochondrial function. MB increases mitochondrial complex IV by 30%, enhances cellular oxygen consumption by 37-70%, increases heme synthesis, and reverses premature senescence caused by H2O2 or cadmium. MB also induces phase-2 antioxidant enzymes in hepG2 cells. Flavin-dependent enzymes are known to use NAD(P)H to reduce MB to leucomethylene blue (MBH2), whereas cytochrome c reoxidizes MBH2 to MB. Experiments on lysates from rat liver mitochondria suggest the ratio MB/cytochrome c is important for the protective actions of MB. We propose that the cellular senescence delay caused by MB is due to cycling between MB and MBH2 in mitochondria, which may partly explain the increase in specific mitochondrial activities. Cycling of MB between oxidized and reduced forms may block oxidant production by mitochondria. Mitochondrial dysfunction and oxidative stress are thought to be key aberrations that lead to cellular senescence and aging. MB may be useful to delay mitochondrial dysfunction with aging and the decrease in complex IV in Alzheimer disease.

  15. Improving the performance of methylene blue sensitized photopolymer by doping with nickel ion

    NASA Astrophysics Data System (ADS)

    Aswathy, G.; Rajesh, C. S.; Sreekumar, K.; Joseph, R.; Kartha, C. Sudha

    2016-05-01

    Holographic performance of an economically cheap metal ion doped photopolymer material is presented. We investigated the effect of incorporation of nickel ion into the methylene blue sensitized poly (vinyl alcohol)/acrylamide (MBPVA/AA) photopolymer system. The composition and preliminary characterization of the developed photopolymer material is reported. The presence of nickel ion improves the diffraction efficiency, stability of the material and it operates in a wide range of spatial frequencies (550-2000 lines/mm) at exposure energy of 100 mJ/cm2. When nickel ion concentration was 0.01 mM, maximum diffraction efficiency of 84% at exposure energy of 100 mJ/cm2 with spatial frequency 1335 lines/mm could be achieved for gratings recorded using wavelength of 632.8 nm. The material showed panchromaticity with more than 70% diffraction efficiency in both blue and green regions. Effects of humidity and temperature on the stored gratings were studied by keeping films in different environmental conditions. Suitability of recording large area holograms was also explored.

  16. Sugarcane bagasse for the removal of erythrosin B and methylene blue from aqueous waste

    NASA Astrophysics Data System (ADS)

    Sharma, Pankaj; Kaur, Harleen

    2011-12-01

    Present study explores the potentiality of locally available cellulose, hemicellulose and lignin-rich agricultural by-product sugarcane bagasse (SB) for the removal of erythrosin B (EB) and methylene blue (MB) from aqueous waste. The SB has been characterized by Fourier transform infrared and scanning electron microscopy analytical techniques. Batch experiments have been carried out to determine the influence of parameters like initial dye concentration, pH of the medium, contact time between the adsorbate and adsorbent, weight of adsorbent and system temperature on the removal of EB and MB. Optimum conditions for adsorption are found to be pH 9, temperature 308 K and an equilibration time of 1 h. Under these conditions equilibrium isotherms have been analysed by Langmuir and Freundlich isotherm equations. Based on the Langmuir adsorption isotherm model, the predicted maximum monolayer adsorption capacities of SB for EB and MB are found to be 500 mg g-1 (at 328 K) and 1,000 mg g-1 (at 308 K), respectively. The separation factor reveals the favourable nature of the isotherm for the studied dyes—SB system. The thermodynamic study indicates that the adsorptions of dyes are spontaneous and endothermic process. High temperatures favour EB adsorption whereas optimum temperature for MB adsorption is 318 K.

  17. Fully-automated radiosynthesis and in vitro uptake investigation of [N-methyl-¹¹C]methylene blue.

    PubMed

    Schweiger, Lutz F; Smith, Tim A D

    2013-10-01

    Malignant melanoma is a type of skin cancer which can spread rapidly if not detected early and left untreated. Positron Emission Tomography (PET) is a powerful imaging technique for detecting cancer but with only a limited number of radiotracers available the development of novel PET probes for detection and prevention of cancer is imperative. In the present study we present the fully-automated radiosynthesis of [N-methyl-(11)C]methylene blue and an in vitro uptake study in metastasic melanoma cell lines. Using the GE TRACERlab FXc Pro module [N-methyl-(11)C]methylene blue was isolated via solid-phase extraction in an average time of 36 min after end of bombardment and formulated with a radiochemical purity greater than 95%. The in vitro uptake study of [N-methyl-(11)C]methylene blue in SK-MEL28 melanin-expressing melanoma cell line demonstrated in site-specific binding of 51% promoting it as a promising melanoma PET imaging agent.

  18. Optimization of methylene blue using Ca(2+) and Zn(2+) bio-polymer hydrogel beads: A comparative study.

    PubMed

    Kumar, M; Tamilarasan, R; Arthanareeswaran, G; Ismail, A F

    2015-11-01

    Recently noted that the methylene blue cause severe central nervous system toxicity. It is essential to optimize the methylene blue from aqueous environment. In this study, a comparison of an optimization of methylene blue was investigated by using modified Ca(2+) and Zn(2+) bio-polymer hydrogel beads. A batch mode study was conducted using various parameters like time, dye concentration, bio-polymer dose, pH and process temperature. The isotherms, kinetics, diffusion and thermodynamic studies were performed for feasibility of the optimization process. Freundlich and Langmuir isotherm equations were used for the prediction of isotherm parameters and correlated with dimensionless separation factor (RL). Pseudo-first order and pseudo-second order Lagegren's kinetic equations were used for the correlation of kinetic parameters. Intraparticle diffusion model was employed for diffusion of the optimization process. The Fourier Transform Infrared Spectroscopy (FTIR) shows different absorbent peaks of Ca(2+) and Zn(2+) beads and the morphology of the bio-polymer material analyzed with Scanning Electron Microscope (SEM). The TG & DTA studies show that good thermal stability with less humidity without production of any non-degraded products.

  19. Water-insoluble sericin/β-cyclodextrin/PVA composite electrospun nanofibers as effective adsorbents towards methylene blue.

    PubMed

    Zhao, Rui; Wang, Yong; Li, Xiang; Sun, Bolun; Jiang, Ziqiao; Wang, Ce

    2015-12-01

    A novel water-insoluble sericin/β-cyclodextrin/poly (vinyl alcohol) composite nanofiber adsorbent was prepared by electrospinning and followed by thermal crosslinking for removal of cationic dye methylene blue from aqueous solution. Fourier transform infrared spectroscopy and solubility experiments confirmed that sericin and β-cyclodextrin were incorporated into the nanofibers and the crosslinking reaction occurred successfully. Kinetics, isotherms and thermodynamics analysis were studied for adsorption of methylene blue. The adsorption process is better fitted with the pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacities are 187.97, 229.89, and 261.10mg/g at the temperatures 293, 313 and 333 K, respectively. Thermodynamic parameters showed that methylene blue adsorption was endothermic and spontaneous. In addition, the fiber membrane adsorbent could be easily separated from dye solution and showed high recyclable removal efficiency. All these results suggest that crosslinked sericin/β-cyclodextrin/poly(vinyl alcohol) composite nanofibers could be potential recyclable adsorbents in dye wastewater treatment.

  20. Water-insoluble sericin/β-cyclodextrin/PVA composite electrospun nanofibers as effective adsorbents towards methylene blue.

    PubMed

    Zhao, Rui; Wang, Yong; Li, Xiang; Sun, Bolun; Jiang, Ziqiao; Wang, Ce

    2015-12-01

    A novel water-insoluble sericin/β-cyclodextrin/poly (vinyl alcohol) composite nanofiber adsorbent was prepared by electrospinning and followed by thermal crosslinking for removal of cationic dye methylene blue from aqueous solution. Fourier transform infrared spectroscopy and solubility experiments confirmed that sericin and β-cyclodextrin were incorporated into the nanofibers and the crosslinking reaction occurred successfully. Kinetics, isotherms and thermodynamics analysis were studied for adsorption of methylene blue. The adsorption process is better fitted with the pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacities are 187.97, 229.89, and 261.10mg/g at the temperatures 293, 313 and 333 K, respectively. Thermodynamic parameters showed that methylene blue adsorption was endothermic and spontaneous. In addition, the fiber membrane adsorbent could be easily separated from dye solution and showed high recyclable removal efficiency. All these results suggest that crosslinked sericin/β-cyclodextrin/poly(vinyl alcohol) composite nanofibers could be potential recyclable adsorbents in dye wastewater treatment. PMID:26433644

  1. Photocatalytic dechlorination of polychlorinated biphenyls using leuco-methylene blue sensitization, broad spectrum visible lamps, or light emitting diodes.

    PubMed

    Izadifard, Maryam; Langford, Cooper H; Achari, Gopal

    2010-12-01

    Photocatalytic routes to dechlorinate polychlorinated biphenyls (PCBs) have considerable potential for development. This paper describes efficient dye-photocatalyzed processes which can be driven by long wavelength light sources including light-emitting diodes (LEDs), fluorescent lamps, and quite probably sunlight. The reduced form of methylene blue (MB), leuco-methylene blue (LMB), has previously been found to photoinduce dechlorination of chloroaromatics with an electron transfer from its triplet excited state. Sodium borohydride, used in this case is an efficient sacrificial reductant, which can maintain LMB as the major species in competition with air oxidation of LMB to MB. There is also evidence that it plays a further (chain reaction) role in promoting the LMB photodechlorination process as well. The generality of the photoelectron transfer from reduced members of the phenothiazine dye family is demonstrated with phenothiazine and leuco-methylene green when a wavelength (UV) is chosen to produce the highly reductive triplet. It is likely that dechlorination can be initiated by many triplet excited states with adequate reduction potential.

  2. Quantification of metabolically active biomass using Methylene Blue dye Reduction Test (MBRT): measurement of CFU in about 200 s.

    PubMed

    Bapat, Prashant; Nandy, Subir Kumar; Wangikar, Pramod; Venkatesh, K V

    2006-04-01

    Quantification of viable cells is a critical step in almost all biological experiments. Despite its importance, the methods developed so far to differentiate between viable and non-viable cells suffer from major limitations such as being time intensive, inaccurate and expensive. Here, we present a method to quantify viable cells based on reduction of methylene blue dye in cell cultures. Although the methylene blue reduction method is well known to check the bacterial load in milk, its application in the quantification of viable cells has not been reported. We have developed and standardized this method by monitoring the dye reduction rate at each time point for growth of Escherichia coli. The standard growth curve was monitored using this technique. The Methylene Blue dye Reduction Test (MBRT) correlates very well with Colony Forming Units (CFU) up to a 800 live cells as established by plating. The test developed is simple, accurate and fast (200 s) as compared to available techniques. We demonstrate the utility of the developed assay to monitor CFU rapidly and accurately for E. coli, Bacillus subtilis and a mixed culture of E. coli and B. subtilis. This assay, thus, has a wide applicability to all types of aerobic organisms.

  3. A pulsed electric field enhances cutaneous delivery of methylene blue in excised full-thickness porcine skin.

    PubMed

    Johnson, P G; Gallo, S A; Hui, S W; Oseroff, A R

    1998-09-01

    We used electric pulses to permeabilize porcine stratum corneum and demonstrate enhanced epidermal transport of methylene blue, a water-soluble cationic dye. Electrodes were placed on the outer surface of excised full-thickness porcine skin, and methylene blue was applied to the skin beneath the positive electrode; 1 ms pulses of up to 240 V were delivered at frequencies of 20-100 Hz for up to 30 min. The amount of dye in a skin sample was determined from absorbance spectra of dissolved punch biopsy sections. Penetration depth and concentration of the dye were measured with light and fluorescence microscopy of cryosections. At an electric exposure dose VT (applied voltage x frequency x pulse width x treatment duration) of about 4700 Vs, there is a threshold for efficient drug delivery. Increasing the applied voltage or field application time resulted in increased dye penetration. Transport induced by electric pulses was more than an order of magnitude greater than that seen following iontophoresis. We believe that the enhanced cutaneous delivery of methylene blue is due to a combination of de novo permeabilization of the stratum corneum by electric pulses, passive diffusion through the permeabilization sites, and electrophoretic and electroosmotic transport by the electric pulses. Pulsed electric fields may have important applications for drug delivery in a variety of fields where topical drug delivery is a goal.

  4. Distribution of Methylene Blue after Injection into the Epidural Space of Anaesthetized Pregnant and Non-Pregnant Sheep

    PubMed Central

    Moll, Xavier; García, Felix; Ferrer, Rosa Isabel; Santos, Laura; Aguilar, Adrià; Andaluz, Anna

    2014-01-01

    The aim of the study was to determine the distribution of different volumes of methylene blue solution injected into the epidural space in anaesthetized pregnant and non-pregnant sheep, to evaluate its cranial distribution and to compare between them. Fifteen pregnant and fifteen non-pregnant sheep were included in the study. Sheep were anaesthetized and received 0.05, 0.1, or 0.2 mL/kg of a lumbosacral epidural solution containing 0.12% methylene blue in 0.9% saline. Thirty minutes after the epidural injection, the ewes were euthanized. The extension of the dye within the epidural space was measured, and the correlation between the volume of the dye injected and the number of stained vertebrae was evaluated. The cranial migration of the dye between pregnant and non-pregnant sheep was also compared. The results show that the volume of methylene blue injected epidurally into pregnant and non-pregnant sheep correlated directly with its cephalic distribution into the epidural space; and a volume of 0.1 mL/kg or 0.2 mL/kg stained up to the first lumbar segment in pregnant and non-pregnant sheep, respectively. Also, the results suggest that the volume of drugs administered into the epidural space of pregnant sheep should be half the volume that would be used in non-pregnant sheep. PMID:24709655

  5. Identification of methylene diphenyl diisocyanate thermal degradation products in a generation chamber by liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Gagne, Sébastien; Cloutier, Yves

    2016-01-01

    Isocyanate thermal degradation characterization by liquid chromatography coupled with electrospray tandem mass spectrometry has been performed to elucidate the methylene diphenyl diisocyanate (MDI) thermal degradation structure emitted in a generation chamber using a temperature between 50°C and 180°C to produce MDI vapors. [M+H](+) ions containing an isocyanate functional group were studied by tandem mass spectrometry. The [M+H](+) ion analyses based on the combination of full scans and precursor ion scans were useful for identifying all structures. The compounds emitted were identified and validated as a mixture of compounds containing amine and isocyanate functions. Residual MDI, methylene diphenyl amino-isocyanate, and methylene diphenyl diamine were identified. Polymerized forms of these structures were also observed because amine and isocyanate chemical functions react rapidly to polymerize. These results must be used with special care by scientists establishing sensitization diagnostics and developing sampling devices using generation chambers as they must be related to MDI behavior in workplaces. Even if pure MDI is introduced in the generation chamber, several different compounds are generated when the MDI is heated at a high temperature. This can result in some misleading interpretations for non-specific isocyanate sampling device development and sensitization diagnostics as MDI is present in the chamber with other compounds with known adverse effects.

  6. Tin Powder-Promoted One-Pot Construction of α-Methylene-γ-lactams and Spirolactams from Aldehydes or Ketones, Acylhydrazines, and 2-(Bromomethyl)acrylate.

    PubMed

    Xu, Yanli; Huang, Danfeng; Wang, Ke-Hu; Ma, Junyan; Su, Yingpeng; Fu, Ying; Hu, Yulai

    2015-12-18

    A concise and efficient method for the synthesis of α-methylene-γ-lactams is developed from multicomponent one-pot reactions of aldehydes or ketones, hydrazides, and ethyl 2-(bromomethyl)acrylate promoted by tin powder. The reaction proceeds smoothly under mild reaction conditions without using any catalyst to give the corresponding products in high yields. α-Methylene-γ-spirolactams can also be prepared from cyclic ketones. PMID:26577682

  7. Treatment and toxicity evaluation of methylene blue using electrochemical oxidation, fly ash adsorption and combined electrochemical oxidation-fly ash adsorption.

    PubMed

    Wang, Kai-sung; Wei, Ming-Chi; Peng, Tzu-Huan; Li, Heng-Ching; Chao, Shu-Ju; Hsu, Tzu-Fang; Lee, Hong-Shen; Chang, Shih-Hsien

    2010-08-01

    Treatment of a basic dye, methylene blue, by electrochemical oxidation, fly ash adsorption, and combined electrochemical oxidation-fly ash adsorption was compared. Methylene blue at 100 mgL(-1) was used in this study. The toxicity was also monitored by the Vibrio fischeri light inhibition test. When electrochemical oxidation was used, 99% color and 84% COD were removed from the methylene blue solution in 20 min at a current density of 428 Am(-2), NaCl of 1000 mgL(-1), and pH(0) of 7. However, the decolorized solution showed high toxicity (100% light inhibition). For fly ash adsorption, a high dose of fly ash (>20,000 mgL(-1)) was needed to remove methylene blue, and the Freundlich isotherm described the adsorption behavior well. In the combined electrochemical oxidation-fly ash adsorption treatment, the addition of 4000 mgL(-1) fly ash effectively reduced intermediate toxicity and decreased the COD of the electrochemical oxidation-treated methylene blue solution. The results indicated that the combined process effectively removed color, COD, and intermediate toxicity of the methylene blue solution.

  8. Methylene-Functionalize Saponite: A New Type of Organoclay with CH2 Groups Substituting for Bridging Oxygen Centers in the Tetrahedral Sheet

    PubMed Central

    Xue, Siqi; Pinnavaia, Thomas J.

    2010-01-01

    The synthesis of saponite in the presence of bis(triethoxysilyl)methane (BTESM) as an organosilicon reagent results in the replacement of up to 33.3 % of the oxygen atoms in the tetrahedral sheet by bridging methylene groups. The methylene-functionalized saponites represent a new form of covalently-bonded organoclay that truly is isomorphic with purely inorganic saponite made under equivalent reaction conditions from sodium silicate as the silicon source. The isoelectronic and isolobal relationship between methylene and bridging oxygen centers is essential for methylene saponite formation. Bridging ethylene groups are not incorporated into the Kagome net of the basal surfaces due to a mismatch in bridging group size. The textural properties of the methylene saponites are similar to those for purely inorganic magnesium saponite made under equivalent synthetic conditions in the absence of BTESM. Layer stacking disorders afford large surface areas (~550 to 650 m2/g), making the methylene saponites attractive candidates for use as adsorbents and functional fillers for polymer composites. PMID:20508733

  9. Connecting glutathione with immune responses to occupational methylene diphenyl diisocyanate exposure.

    PubMed

    Wisnewski, Adam V; Liu, Jian; Redlich, Carrie A

    2013-09-01

    Methylene diphenyl diisocyanate (MDI) is among the leading chemical causes of occupational asthma world-wide, however, the mechanisms of disease pathogenesis remain unclear. This study tests the hypothesis that glutathione (GSH) reacts with MDI to form quasi-stable conjugates, capable of mediating the formation of MDI-conjugated "self" protein antigens, which may participate in pathogenic inflammatory responses. To test this hypothesis, an occupationally relevant dose of MDI (0.1%w/v) was reacted with varying concentrations of GSH (10μM-10mM), and the reaction products were characterized with regard to mass/structure, and ability to carbamoylate human albumin, a major carrier protein for MDI in vivo. LC-MS/MS analysis of GSH-MDI reaction products identified products possessing the exact mass of previously described S-linked bis(GSH)-MDI and its partial hydrolysis product, as well as novel cyclized GSH-MDI structures. Upon co-incubation of GSH-MDI reaction products with human albumin, MDI was rapidly transferred to specific lysines of albumin, and the protein's native conformation/charge was altered, based on electrophoretic mobility. Three types of modification were observed, intra-molecular MDI cross-linking, addition of partially hydrolyzed MDI, and addition of "MDI-GSH", where MDI's 2nd NCO had reacted with GSH's "N-terminus". Importantly, human albumin carbamoylated by GSH-MDI was specifically recognized by serum IgG from MDI exposed workers, with binding dependent upon the starting GSH concentration, pH, and NaCl levels. Together, the data define a non-enzymatic, thiol-mediated transcarbamoylating mechanism by which GSH may promote immune responses to MDI exposure, and identify specific factors that might further modulate this process.

  10. Comparative evaluation of methylene blue and demeclocycline for enhancing optical contrast of brain neoplasms

    NASA Astrophysics Data System (ADS)

    Wirth, Dennis J.

    Brain tumors cause significant morbidity and mortality even when benign. Completeness of resection of brain tumors has been associated with better quality of life. However, that is often difficult to accomplish. The goal of this study was to evaluate the feasibility of using contrast enhanced multimodal confocal imaging for intraoperative detection of brain neoplasms. Different types of benign and malignant, primary and metastatic brain tumors, stained with Methylene Blue (MB) as a contrast agent, were imaged. MB is a traditional histopathologic stain that absorbs light in the red spectral range and fluoresces in the near infrared. It is FDA-approved for in vivo staining of human skin and breast tissue. Optical images showed good correlation with histopathology, demonstrating the potential of contrast enhanced multimodal confocal imaging for intraoperative detection of brain neoplasms ex vivo. However, the safety of MB for staining human brain in vivo is questionable. Demeclocycline (DMN), an antibiotic of the tetracycline family, has shown to be effective in differentiating normal from cancerous tissue in various organs. DMN is a fluorophore, which absorbs light in the violet spectral range and has a broad emission band covering green and yellow wavelengths. It is commonly used to treat infection and inflammatory disorders, and could provide a safer alternative to MB. To test this hypothesis, fresh excess human brain tissues were bisected and stained with aqueous solutions of either MB or DMN and then imaged. Reflectance and fluorescence images acquired from tissues stained with the two dyes were compared, and correlated with processed H&E histopathology. Comparison showed similar staining patterns and contrast of diagnostic features in glioblastomas, stained using either MB or DMN. The results show potential of both MB and DMN for the intraoperative detection of microscopic nests of brain neoplasms. Further studies will establish safety and efficacy of these

  11. Development of therapeutic Au-methylene blue nanoparticles for targeted photodynamic therapy of cervical cancer cells.

    PubMed

    Yu, Jiashing; Hsu, Che-Hao; Huang, Chih-Chia; Chang, Po-Yang

    2015-01-14

    Photodynamic therapy (PDT) involves the cellular uptake of a photosensitizer (PS) combined with oxygen molecules and light at a specific wavelength to be able to trigger cancer cell death via the apoptosis pathway, which is less harmful and has less inflammatory side effect than necrosis. However, the traditional PDT treatment has two main deficiencies: the dark toxicity of the PS and the poor selectivity of the cellular uptake of PS between the target cells and normal tissues. In this work, methylene blue (MB), a known effective PS, combined with Au nanoparticles (NPs) was prepared using an intermolecular interaction between a polystyrene-alt-maleic acid (PSMA) layer on the Au NPs and MB. The Au@polymer/MB NPs produced a high quantum yield of singlet oxygen molecules, over 50% as much as that of free MB, when they were excited by a dark red light source at 660 nm, but without significant dark toxicity. Furthermore, transferrin (Tf) was conjugated on the Au@polymer/MB NPs via an EDC/NHS reaction to enhance the selectivity to HeLa cells compared to 3T3 fibroblasts. With a hand-held single laser treatment (32 mW/cm) for 4 min, the new Au@polymer/MB-Tf NPs showed a 2-fold enhancement of PDT efficiency toward HeLa cells over the use of free MB at 4 times dosage. Cellular staining examinations showed that the HeLa cells reacted with Au@polymer/MB-Tf NPs and the 660 nm light excitation triggered PDT, which caused the cells to undergo apoptosis ("programmed" cell death). We propose that applying this therapeutic Au@polymer/MB-Tf nanoagent is facile and safe for delivery and cancer cell targeting to simultaneously minimize side effects and accomplish a significant enhancement in photodynamic therapeutic efficiency toward next-generation nanomedicine development.

  12. Adsorptive removal of methylene blue by rhamnolipid-functionalized graphene oxide from wastewater.

    PubMed

    Wu, Zhibin; Zhong, Hua; Yuan, Xingzhong; Wang, Hou; Wang, Lele; Chen, Xiaohong; Zeng, Guangming; Wu, Yan

    2014-12-15

    In this article, a rhamnolipid-functionalized graphene oxide (RL-GO) hybrid was prepared by one-step ultrasonication and adsorptive removal of methylene blue (MB) from both artificial and real wastewater by the RL-GO was investigated. The Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) area and Zeta potential analysis were used to characterize the adsorbent. The results showed that RL-GO had abundant functional groups and a mesopores feature. MB adsorption by the RL-GO increased with increase in adsorbent dose, pH, temperature and initial MB concentration, while it was insensitive to ionic strength variation. The adsorption kinetics fitted well to the pseudo-second-order model with correlation coefficients greater than 0.999. The Intra-particle diffusion and Boyd's film-diffusion models showed that the rate-controlled step was dominated by film-diffusion in the beginning and then followed by intra-particle diffusion. The adsorption isotherm was fitted by adsorption models with the suitability in order of BET > Freundlich > Langmuir > Temkin, based on comparison between correlation coefficients. Thermodynamic analysis of equilibriums suggested that the adsorption MB on RL-GO was spontaneous and endothermic. The adsorption mechanism was also proposed to be electrostatic attraction, π-π interaction and hydrogen bond. In addition, the real wastewater experiment, the regeneration study and the comparative cost analysis showed that the RL-GO composites could be a cost-effective and promising sorbent for MB wastewater treatment owing to its high efficiency and excellent reusability.

  13. Mechanism of Methylene Blue adsorption on hybrid laponite-multi-walled carbon nanotube particles.

    PubMed

    Manilo, Maryna; Lebovka, Nikolai; Barany, Sandor

    2016-04-01

    The kinetics of adsorption and parameters of equilibrium adsorption of Methylene Blue (MB) on hybrid laponite-multi-walled carbon nanotube (NT) particles in aqueous suspensions were determined. The laponite platelets were used in order to facilitate disaggregation of NTs in aqueous suspensions and enhance the adsorption capacity of hybrid particles for MB. Experiments were performed at room temperature (298 K), and the laponite/NT ratio (Xl) was varied in the range of 0-0.5. For elucidation of the mechanism of MB adsorption on hybrid particles, the electrical conductivity of the system as well as the electrokinetic potential of laponite-NT hybrid particles were measured. Three different stages in the kinetics of adsorption of MB on the surface of NTs or hybrid laponite-NT particles were discovered to be a fast initial stage I (adsorption time t=0-10 min), a slower intermediate stage II (up to t=120 min) and a long-lasting final stage III (up to t=24hr). The presence of these stages was explained accounting for different types of interactions between MB and adsorbent particles, as well as for the changes in the structure of aggregates of NT particles and the long-range processes of restructuring of laponite platelets on the surface of NTs. The analysis of experimental data on specific surface area versus the value of Xl evidenced in favor of the model with linear contacts between rigid laponite platelets and NTs. It was also concluded that electrostatic interactions control the first stage of adsorption at low MB concentrations.

  14. Methylene Blue Removal by Biochars from Food Industry By-Products

    NASA Astrophysics Data System (ADS)

    Orfanos, Alexis; Manariotis, Ioannis D.; Karapanagioti, Hrissi K.

    2016-04-01

    Biomass produced by food industries is mainly used as feedstock or in composting. In recent years, considerable research effort has been focused on the production of biochar under oxygen-limited conditions from carbon-rich biomass, such as food industry by-products, as mitigation measure for global warming once it is used as a soil amendment. The present study presents the findings of an experimental work, which investigated the use of different biochars for the removal of methylene blue (MB) from aqueous solutions. Biochars were produced from malt spent rootlets (MSR) from brewering and espresso coffee residue from coffee shops. MSR was pyrolyzed at temperatures of 300, 400, 500, 750, 850, and 900oC and the coffee residue was pyrolyzed at 850oC. The charring process was performed under limited-oxygen conditions using specialized containers. The surface area and the porosity of the materials were determined. Batch experiments were conducted in order to evaluate the sorption capacity of the above materials, and samples were agitated for 24 h at 25oC, at an optimum pH of about 7. Kinetic analysis was conducted over a period of 24 h, and isotherm studies were also constructed. The surface area of biochar produced from MSR and the MB removal were considerably increased at pyrolysis temperatures higher than 500oC. At 850oC, the maximum surface area value (300 m2 g-1) was observed, and the MB sorption capacity was 99 mg g-1. Based on the kinetic experimental data, sorption capacities at 120 min were over 58% of their equilibrium values for the biochars used. The maximum MB sorption capacity, based on the isotherm data, was 130 mg g-1, for the two biochars employed.

  15. Sensitive analytical performance of folding based biosensor using methylene blue tagged aptamers.

    PubMed

    Catanante, Gaëlle; Mishra, Rupesh K; Hayat, Akhtar; Marty, Jean-Louis

    2016-06-01

    This work demonstrates the development of a folding based electrochemical aptasensor using methylene blue (MB) tagged anti-Ochratoxin A (OTA) aptamers. Different aptamer coupling strategies were tested using Hexamethylenediamine, polyethylene glycol, simple adsorption and diazonium coupling mechanism. The best sensitivity was recorded by oxidation of amines using hexamethylenediamine (HDMA) on screen printed carbon electrode (SPCE). To achieve the direct detection of OTA, aptamer conjugated redox probe was used and detection was demonstrated based on the conformational changes in aptamer structure upon OTA sensing. Signaling in this class of sensors arises from changes in electron transfer efficiency upon target-induced changes in the conformation/flexibility of the aptamer probe. These changes can be readily recorded electrochemically. The developed aptasensor is unique in its own mechanism as redox probe tagged aptamer coupling such as MB has never been tried to immobilize using long carbon chain spacers as, addition of spacers would provide more sensitive detection methods. A good dynamic range 0.01-5ng/ml was obtained for OTA with Limit of detection (LOD) 0.01ng/ml and Limit of quantification (LOQ) of 0.03ng/ml respectively. The good reproducibility was recorded with RSD% of 3.75. The obtained straight line equation was y=0.4035x+0.90311, r=0.9976. We believe that the sensor design guidelines outlined here represents a general strategy for developing new folding-based electrochemical aptasensors. The developed aptasensor was extended to screen cocoa samples for OTA contamination. The cocoa samples were extracted and purified using molecular imprinted polymer (MIP) columns. The aptasensor displayed good recovery values in the range 84-85% thus, exhibited the effectiveness of proposed aptasensor for such complex matrices. PMID:27130100

  16. Photodynamic fungicidal efficacy of hypericin and dimethyl methylene blue against azole-resistant Candida albicans strains.

    PubMed

    Paz-Cristobal, M P; Royo, D; Rezusta, A; Andrés-Ciriano, E; Alejandre, M C; Meis, J F; Revillo, M J; Aspiroz, C; Nonell, S; Gilaberte, Y

    2014-01-01

    Antimicrobial photodynamic therapy (aPDT) is an emerging alternative to treat infections based on the use of photosensitisers (PSs) and visible light. To investigate the fungicidal effect of PDT against azole-resistant Candida albicans strains using two PSs with a different mechanism of action, hypericin (HYP) and 1,9-dimethyl methylene blue (DMMB), comparing their efficacy and the reactive oxygen species (ROS) species involved in their cytotoxicity. Azole-resistant and the azole-susceptible C. albicans strains were used. Solutions of 0.5 and 4 McFarland inoculum of each Candida strain were treated with different concentrations of each PS, and exposed to two light-emitting diode light fluences (18 and 37 J cm⁻²). Mechanistic insight was gained using several ROS quenchers. The minimal fungicidal concentration of HYP for ≥3 log₁₀ CFU reduction (0.5 McFarland) was 0.62 μmol l⁻¹ for most strains, whereas for DMMB it ranged between 1.25 and 2.5 μmol l⁻¹. Increasing the fluence to 37 J cm⁻² allowed to reduce the DMMB concentration. Higher concentrations of both PSs were required to reach a 6 log₁₀ reduction (4 McFarland). H₂O₂ was the main phototoxic species involved in the fungicidal effect of HYP-aPDT whereas ¹O₂ was more important for DMMB-based treatments. aPDT with either HYP or DMMB is effective in killing of C. albicans strains independent of their azole resistance pattern. HYP was more efficient at low fungal concentration and DMMB at higher concentrations. PMID:23905682

  17. Adsorptive removal of methylene blue by rhamnolipid-functionalized graphene oxide from wastewater.

    PubMed

    Wu, Zhibin; Zhong, Hua; Yuan, Xingzhong; Wang, Hou; Wang, Lele; Chen, Xiaohong; Zeng, Guangming; Wu, Yan

    2014-12-15

    In this article, a rhamnolipid-functionalized graphene oxide (RL-GO) hybrid was prepared by one-step ultrasonication and adsorptive removal of methylene blue (MB) from both artificial and real wastewater by the RL-GO was investigated. The Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) area and Zeta potential analysis were used to characterize the adsorbent. The results showed that RL-GO had abundant functional groups and a mesopores feature. MB adsorption by the RL-GO increased with increase in adsorbent dose, pH, temperature and initial MB concentration, while it was insensitive to ionic strength variation. The adsorption kinetics fitted well to the pseudo-second-order model with correlation coefficients greater than 0.999. The Intra-particle diffusion and Boyd's film-diffusion models showed that the rate-controlled step was dominated by film-diffusion in the beginning and then followed by intra-particle diffusion. The adsorption isotherm was fitted by adsorption models with the suitability in order of BET > Freundlich > Langmuir > Temkin, based on comparison between correlation coefficients. Thermodynamic analysis of equilibriums suggested that the adsorption MB on RL-GO was spontaneous and endothermic. The adsorption mechanism was also proposed to be electrostatic attraction, π-π interaction and hydrogen bond. In addition, the real wastewater experiment, the regeneration study and the comparative cost analysis showed that the RL-GO composites could be a cost-effective and promising sorbent for MB wastewater treatment owing to its high efficiency and excellent reusability. PMID:25314573

  18. Analytical determination of specific 4,4'-methylene diphenyl diisocyanate hemoglobin adducts in human blood.

    PubMed

    Gries, Wolfgang; Leng, Gabriele

    2013-09-01

    4,4'-Methylene diphenyl diisocyanate (MDI) is one of the most important isocyanates in the industrial production of polyurethane and other MDI-based synthetics. Because of its high reactivity, it is known as a sensitizing agent, caused by protein adducts. Analysis of MDI is routinely done by determination of the nonspecific 4,4'-methylenedianiline as a marker for MDI exposure in urine and blood. Since several publications have reported specific adducts of MDI and albumin or hemoglobin, more information about their existence in humans is necessary. Specific adducts of MDI and hemoglobin were only reported in rats after high-dose MDI inhalation. The aim of this investigation was to detect the hemoglobin adduct 5-isopropyl-3-[4-(4-aminobenzyl)phenyl]hydantoin (ABP-Val-Hyd) in human blood for the first time. We found values up to 5.2 ng ABP-Val-Hyd/g globin (16 pmol/g) in blood samples of workers exposed to MDI. Because there was no information available about possible amounts of this specific MDI marker, the analytical method focused on optimal sensitivity and selectivity. Using gas chromatography-high-resolution mass spectrometry with negative chemical ionization, we achieved a detection limit of 0.02 ng ABP-Val-Hyd/g globin (0.062 pmol/g). The robustness of the method was confirmed by relative standard deviations between 3.0 and 9.8 %. Combined with a linear detection range up to 10 ng ABP-Val-Hyd/g globin (31 pmol/g), the enhanced precision parameter demonstrates that the method described is optimized for screening studies of the human population. PMID:23839327

  19. Cellular mechanisms of plasmalemmal sealing and axonal repair by polyethylene glycol and methylene blue.

    PubMed

    Spaeth, C S; Robison, T; Fan, J D; Bittner, G D

    2012-05-01

    Mammalian neurons and all other eukaryotic cells endogenously repair traumatic injury within minutes by a Ca²⁺-induced accumulation of vesicles that interact and fuse with each other and the plasmalemma to seal any openings. We have used uptake or exclusion of extracellular fluorescent dye to measure the ability of rat hippocampal B104 cells or rat sciatic nerves to repair (seal) transected neurites in vitro or transected axons ex vivo. We report that endogenous sealing in both preparations is enhanced by Ca²⁺-containing solutions and is decreased by Ca²⁺-free solutions containing antioxidants such as dithiothreitol (DTT), melatonin (MEL), methylene blue (MB), and various toxins that decrease vesicular interactions. In contrast, the fusogen polyethylene glycol (PEG) at 10-50 mM artificially seals the cut ends of B104 cells and rat sciatic axons within seconds and is not affected by Ca²⁺ or any of the substances that affect endogenous sealing. At higher concentrations, PEG decreases sealing of transected axons and disrupts the plasmalemma of intact cells. These PEG-sealing data are consistent with the hypothesis that lower concentrations of PEG directly seal a damaged plasmalemma. We have considered these and other data to devise a protocol using a well-specified series of solutions that vary in tonicity, Ca²⁺, MB, and PEG content. These protocols rapidly and consistently repair (PEG-fuse) rat sciatic axons in completely cut sciatic nerves in vivo rapidly and dramatically to restore long-lasting morphological continuity, action potential conduction, and behavioral functions. PMID:22302626

  20. Connecting glutathione with immune responses to occupational methylene diphenyl diisocyanate exposure

    PubMed Central

    Wisnewski, Adam V; Liu, Jian; Redlich, Carrie A

    2013-01-01

    Methylene diphenyl diisocyanate (MDI) is among the leading chemical causes of occupational asthma world-wide, however, the mechanisms of disease pathogenesis remain unclear. This study tests the hypothesis that glutathione (GSH) reacts with MDI to form quasistable conjugates, capable of mediating the formation of MDI-conjugated “self” protein antigens, which may participate in pathogenic inflammatory responses. To test this hypothesis, an occupationally relevant dose of MDI (0.1% w/v) was reacted with varying concentrations of GSH (10 μM-10 mM), and the reaction products were characterized with regard to mass/structure, and ability to carbamoylate human albumin, a major carrier protein for MDI in vivo. LC-MS/MS analysis of GSH-MDI reaction products identified products possessing the exact mass of previously described S-linked bis(GSH)-MDI and its partial hydrolysis product, as well as novel cyclized GSH-MDI structures. Upon co-incubation of GSH-MDI reaction products with human albumin, MDI was rapidly transferred to specific lysines of albumin, and the protein's native conformation/charge was altered, based on electrophoretic mobility. Three types of modification were observed, intra-molecular MDI cross-linking, addition of partially hydrolyzed MDI, and addition of “MDI-GSH”, where MDI's 2nd NCO had reacted with GSH's “N-terminus”. Importantly, human albumin carbamoylated by GSH-MDI was specifically recognized by serum IgG from MDI exposed workers, with binding dependent upon the starting GSH concentration, pH, and NaCl levels. Together, the data define a non-enzymatic, thiol-mediated transcarbamoylating mechanism by which GSH may promote immune responses to MDI exposure, and identify specific factors that might further modulate this process. PMID:23791970

  1. Neuroprotective and Functional Improvement Effects of Methylene Blue in Global Cerebral Ischemia.

    PubMed

    Lu, Qing; Tucker, Donovan; Dong, Yan; Zhao, Ningjun; Zhang, Quanguang

    2016-10-01

    Transient global cerebral ischemia (GCI) causes delayed neuronal cell death in the vulnerable hippocampus CA1 subfield, as well as behavioral deficits. Ischemia reperfusion (I/R) produces excessive reactive oxygen species and plays a key role in brain injury. The mitochondrial electron respiratory chain is the main cellular source of free radical generation, and dysfunction of mitochondria has a significant impact on the neuronal cell death in ischemic brain. The aim of the present study is to investigate the potential beneficial effects of methylene blue (MB) in a four-vessel occlusion (4VO) GCI model on adult male rats. MB was delivered at a dose of 0.5 mg/kg/day for 7 days, through a mini-pump implanted subcutaneously after GCI. We first found that MB significantly improved ischemic neuronal survival in the hippocampal CA1 region as measured by cresyl violet staining as well as NeuN staining. We also found that MB has the ability to rescue ischemia-induced decreases of cytochrome c oxidase activity and ATP generation in the CA1 region following I/R. Further analysis with labeling of MitoTracker® Red revealed that the depolarization of mitochondrial membrane potential (MMP) was markedly attenuated following MB treatment. In addition, the induction of caspase-3, caspase-8, and caspase-9 activities and the increased numbers of TUNEL-positive cells of the CA1 region were significantly reduced by MB application. Correspondingly, Barnes maze tests showed that the deterioration of spatial learning and memory performance following GCI was significantly improved in the MB-treatment group compared to the ischemic control group. In summary, our study suggests that MB may be a promising therapeutic agent targeting neuronal cell death and cognitive deficits following transient global cerebral ischemia.

  2. [Study on treatment of methylene blue wastewater by fly ash adsorption-Fenton and thermal regeneration].

    PubMed

    Bai, Yu-Jie; Zhang, Ai-Li; Zhou, Ji-Ti

    2012-07-01

    The physicochemical properties of water-washed fly ash (FA) and acid modified fly ash (M-FA) were investigated. The adsorption of methylene blue by FA and M-FA were studied by batch experiments. Two methods, Fenton-drive oxidation regeneration and thermal regeneration, were used for regeneration of the used FA and M-FA. The result showed that the rate of adsorption process followed the second order kinetics and the adsorption followed Langmuir isotherms. The adsorption equilibrium time was 30 min, and the equilibrium adsorption capacity of FA and M-FA were 4.22 mg x g(-1) and 5.98 mg x g(-1) respectively. The adsorption capability of M-FA was higher than that of FA. In the range of pH 2-12, the adsorption capacity of M-FA increased with the increase of pH, whereas the adsorption capacity of FA decreased slowly until the pH 8 and then increased. Electrostatic adsorption was the major factor on the adsorption capacity. Around 61% and 55% percentage regeneration (PR) were obtained for FA and M-FA respectively when 78.4 mmol x L(-1) H2O2 and 0.72 mmol x L(-1) Fe2+ were used. When the condition of thermal regeneration was 400 degrees C and 2 h, a positive correlation can be found between the PRs of FA and regeneration times, the PRs were 102%, 104% and 107% in three cycles of adsorption-thermal regeneration process. However a negative correlation can be found between the PRs of M-FA and regeneration times, the PRs were 82%, 75% and 74% in three cycles of adsorption-thermal regeneration process. The PR of FA was higher than that of M-FA, and thermal regeneration was superior to Fenton-drive regeneration. PMID:23002621

  3. Functional Polymeric Systems as Delivery Vehicles for Methylene Blue in Photodynamic Therapy.

    PubMed

    Junqueira, Mariana V; Borghi-Pangoni, Fernanda B; Ferreira, Sabrina B S; Rabello, Bruno R; Hioka, Noboru; Bruschi, Marcos L

    2016-01-12

    Antibiotic-resistant microorganisms have become a global concern, and the search for alternative therapies is very important. Photodynamic therapy (PDT) consists of the use of a nontoxic photosensitizer (PS), light, and oxygen. This combination produces reactive oxygen species and singlet oxygen, which can alter cellular structures. Methylene blue (MB) is a substance from the phenothiazine class often used as a PS. In this work, to facilitate the PS contact within the wounds, we have used Design of Experiments 2(3) plus central point to develop functional polymeric systems. The formulations were composed by poloxamer 407 [15.0, 17.5, or 20.0% (w/w)], Carbopol 934P [0.15, 0.20, or 0.25% (w/w)], and MB [0.25, 0.50, or 0.75% (w/w)]. The sol-gel transition temperature, flow rheometry, in vitro MB release, and ex vivo study of MB cutaneous permeation and retention were investigated. Moreover, the evaluation of photodynamic activity was also analyzed by in vitro degradation of tryptophan by singlet oxygen and using Artemia salina. The determination of the gelation temperature displayed values within the range of 25-37 °C, and the systems with better characteristics were subjected to rheological analysis and in vitro release profiling. The 20/0.15/0.25 formulation showed the best release profile (42.57% at 24 h). This system displayed no significant skin permeation (0.38% at 24 h), and the photooxidation of tryptophan test showed the production of reactive species of oxygen. The toxicity test using A. salina revealed that the MB associated with the light increased the mortality rate by 61.29%. Therefore, investigating the PDT efficacy of the functional polymeric system containing MB will be necessary in the future.

  4. sup 211 At-methylene blue for targeted radiotherapy of human melanoma xenografts: Treatment of micrometastases

    SciTech Connect

    Link, E.M.; Carpenter, R.N. )

    1990-05-15

    Treatment of micrometastases of HX34 human melanoma grown as xenografts in nude mice represents an advanced stage of preclinical investigations concerning targeted radiotherapy of this neoplasm using 3,7-(dimethylamino)phenazathionium chloride methylene blue (MTB) labeled with astatine-211 (211At) (alpha-particle emitter). The therapeutic effectiveness of 211At-MTB administered i.v. was determined by a lung colony assay combined with a search for metastases to organs other than the lungs. A single dose of 211At-MTB lowered the HX34 cell surviving fraction in lungs to below 10% almost independently of the time interval between cell inoculation and radioisotope injection and of 211At-MTB radioactivity within its investigated range. Radiation dose and the time of its administration did, however, influence the size of lung colonies. In contrast, the efficacy of 211At-MTB treatment as assessed by both surviving fraction and colony size was significantly dependent on a number of HX34 cells inoculated initially into mice. These results are explained by a short range of alpha-particles emitted by 211At and a mechanism of growth of lung colonies from tumor cells circulating with blood and blocking lung capillaries. Metastases in organs other than lungs and characteristic of control animals were not found in mice treated with 211At-MTB. The high therapeutic efficacy achieved proved that 211At-MTB is a very efficient scavenger of single melanoma cells distributed through blood and micrometastases with sizes below the limit of clinical detection.

  5. Functional Polymeric Systems as Delivery Vehicles for Methylene Blue in Photodynamic Therapy.

    PubMed

    Junqueira, Mariana V; Borghi-Pangoni, Fernanda B; Ferreira, Sabrina B S; Rabello, Bruno R; Hioka, Noboru; Bruschi, Marcos L

    2016-01-12

    Antibiotic-resistant microorganisms have become a global concern, and the search for alternative therapies is very important. Photodynamic therapy (PDT) consists of the use of a nontoxic photosensitizer (PS), light, and oxygen. This combination produces reactive oxygen species and singlet oxygen, which can alter cellular structures. Methylene blue (MB) is a substance from the phenothiazine class often used as a PS. In this work, to facilitate the PS contact within the wounds, we have used Design of Experiments 2(3) plus central point to develop functional polymeric systems. The formulations were composed by poloxamer 407 [15.0, 17.5, or 20.0% (w/w)], Carbopol 934P [0.15, 0.20, or 0.25% (w/w)], and MB [0.25, 0.50, or 0.75% (w/w)]. The sol-gel transition temperature, flow rheometry, in vitro MB release, and ex vivo study of MB cutaneous permeation and retention were investigated. Moreover, the evaluation of photodynamic activity was also analyzed by in vitro degradation of tryptophan by singlet oxygen and using Artemia salina. The determination of the gelation temperature displayed values within the range of 25-37 °C, and the systems with better characteristics were subjected to rheological analysis and in vitro release profiling. The 20/0.15/0.25 formulation showed the best release profile (42.57% at 24 h). This system displayed no significant skin permeation (0.38% at 24 h), and the photooxidation of tryptophan test showed the production of reactive species of oxygen. The toxicity test using A. salina revealed that the MB associated with the light increased the mortality rate by 61.29%. Therefore, investigating the PDT efficacy of the functional polymeric system containing MB will be necessary in the future. PMID:26673856

  6. Excellent adsorption and desorption characteristics of polypyrrole/TiO2 composite for Methylene Blue

    NASA Astrophysics Data System (ADS)

    Li, Jingjing; Feng, Jiangtao; Yan, Wei

    2013-08-01

    P25 or self-prepared TiO2 coated polypyrrole (PPy/P25 or PPy/TiO2) composites as novel adsorbents were prepared. Their adsorption-desorption characteristics for Methylene Blue (MB) were comparatively investigated. X-ray photoelectron spectroscopy (XPS) showed that PPy/TiO2 possessed higher doping level than PPy/P25. Thermogravimetric analysis (TGA) indicated that PPy/TiO2 contained more PPy than PPy/P25. The results of water vapor adsorption suggested that the PPy/TiO2 composite was more hydrophobic than PPy/P25. The adsorption results revealed that the composites pretreated in the solution with higher pH value exhibited larger adsorption capacities. The ionic concentration in MB solution slightly impacted the removal of MB by the PPy/TiO2 composite. The adsorption equilibrium results showed that the adsorption of MB was completed in a short time of 30 min. Pseudo-second-order and Langmuir isotherm models were effectively employed to describe the adsorption behavior of MB. PPy/TiO2 and PPy/P25 were found to have better removal ability for MB compared with pure PPy; especially PPy/TiO2, on which the maximum adsorption amount was about 3.6 or 5.5 times higher than that of PPy/P25 or pure PPy, respectively. The thermodynamic analysis indicated that the adsorption of MB was spontaneous and endothermic in nature. The regeneration experiments exhibited that PPy/TiO2 can be reused at least seven times without obvious loss of its original adsorption capacity. Electrostatic interaction, hydrogen bonding and hydrophobic interaction played the roles in MB adsorption performance. It is expected that the PPy/TiO2 composite can be considered as a stable adsorbent for dye removal.

  7. Effect of Gelatin-Stabilized Copper Nanoparticles on Catalytic Reduction of Methylene Blue

    NASA Astrophysics Data System (ADS)

    Musa, Aminu; Ahmad, Mansor B.; Hussein, Mohd Zobir; Saiman, Mohd Izham; Sani, Hannatu Abubakar

    2016-10-01

    The synthesis of copper nanoparticles was carried out with gelatin as a stabilizer by reducing CuSO4.5H2O ions using hydrazine. Ascorbic acid and aqueous NaOH were also used as an antioxidant and pH controller, respectively. The effects of NaOH, hydrazine, and concentration of gelatin as stabilizer were studied. The synthesized copper nanoparticles were characterized by UV-vis spectroscopy, XRD, zeta potential measurements, FTIR, EDX, FESEM, and TEM. The formation of CuNPs@Gelatin is initially confirmed by UV-vis spectroscopic analysis with the characteristic band at 583 nm. XRD and TEM reports revealed that CuNPs@Gelatin (0.75 wt.%) is highly crystalline and spherical in shape with optimum average size of 4.21 ± 0.95 nm. FTIR studies indicated the presence of amide group on the surface of the CuNPs indicating the stability of CuNPs which is further supported by zeta potential measurements with the negative optimum value of -37.90 ± 0.6 mV. The CuNPs@G4 showed a good catalytic activity against methylene blue (MB) reduction using NaBH4 as a reducing agent in an aqueous solution. The best enhanced properties of CuNPs@G4 were found for the 0.75 wt.% gelatin concentration. Thermodynamic parameters (Δ H and Δ S) indicate that under the studied temperature, the reduction of MB by CuNPs@G4 is not feasible and had endothermic in nature.

  8. [Study on treatment of methylene blue wastewater by fly ash adsorption-Fenton and thermal regeneration].

    PubMed

    Bai, Yu-Jie; Zhang, Ai-Li; Zhou, Ji-Ti

    2012-07-01

    The physicochemical properties of water-washed fly ash (FA) and acid modified fly ash (M-FA) were investigated. The adsorption of methylene blue by FA and M-FA were studied by batch experiments. Two methods, Fenton-drive oxidation regeneration and thermal regeneration, were used for regeneration of the used FA and M-FA. The result showed that the rate of adsorption process followed the second order kinetics and the adsorption followed Langmuir isotherms. The adsorption equilibrium time was 30 min, and the equilibrium adsorption capacity of FA and M-FA were 4.22 mg x g(-1) and 5.98 mg x g(-1) respectively. The adsorption capability of M-FA was higher than that of FA. In the range of pH 2-12, the adsorption capacity of M-FA increased with the increase of pH, whereas the adsorption capacity of FA decreased slowly until the pH 8 and then increased. Electrostatic adsorption was the major factor on the adsorption capacity. Around 61% and 55% percentage regeneration (PR) were obtained for FA and M-FA respectively when 78.4 mmol x L(-1) H2O2 and 0.72 mmol x L(-1) Fe2+ were used. When the condition of thermal regeneration was 400 degrees C and 2 h, a positive correlation can be found between the PRs of FA and regeneration times, the PRs were 102%, 104% and 107% in three cycles of adsorption-thermal regeneration process. However a negative correlation can be found between the PRs of M-FA and regeneration times, the PRs were 82%, 75% and 74% in three cycles of adsorption-thermal regeneration process. The PR of FA was higher than that of M-FA, and thermal regeneration was superior to Fenton-drive regeneration.

  9. Reduction of methylene green by EDTA: a relation between dielectric constant of medium and activated state.

    PubMed

    Qamar, Noshab; Azmat, Rafia; Naz, Raheela

    2013-01-01

    Kinetics of an alkaline reduction of the methylene green with ethylenediaminetetraaceticacid (EDTA) as a role of dielectric constant of the medium with anecdotal ionic strength in a diverse solvent system (aqueous mixtures of methanol) (10-30%) was studied by measuring the specific rate constant of the reaction spectrophotometrically at λ (max) = 660nm. An effort has been made to give an elucidation of vital role of dielectric constant of the medium captivating into reflection of single sphere and double sphere complex in reaction assortment. This investigation leads to disclose that single sphere complex of the dye and reductant was found to be the most suitable complex existed in a varied organic solvent. The deviation of the theoretical values from experimental results for single sphere and double sphere complex model in the presence of an alkali and nitrate ions were justified through HPLC analysis. HPLC analysis recommended that a considerable amount of the dye degrades in the existence of nitrate ion and alkali and additional peaks which may be of by-product were obtained. This leads to confirm the non identical values of single sphere and double sphere model in the occurrence of nitrate and an alkali. Rate of deletion of color showed a linear liaison with respect to water content below 30% and temperature between 20-40(o)C whereas an increase in the concentration of organic solvent showed the inhibition of dye decoloration at given optimum condition. Therefore study was restricted up to 30% of methanol binary mixtures. A mechanism of reduction of dye has been proposed based on verdict.

  10. Experimental exposure of rats to methylene chloride at varying controlled barometric altitudes

    SciTech Connect

    Lillquist, D.R.

    1990-01-01

    This study investigated combined effects of three methylene chloride (MC) volume/volume concentrations (0,50, and 500 ppm) at three controlled barometric altitudes (760, 640, and 560 torr). This provided a three by three study design. For each scenario, three altitude acclimated (6 days) adult male rats were studied for eight hours in a nose-only inhalation chamber. Blood (0.35 mL) was drawn from the cannulated left carotid artery of each rat at 0, 0.5, 1, 2, 4, and 8 hours and hematocrit, pO[sub 2], pCO[sub 2], pH , total hemoglobin (Hb) and carboxyhemoglobin (CHb) were measured. Time, MC concentration and altitude had significant effects on CHb production. CHb increased with increasing MC concentration over time. Increased barometric altitude (reduced partial pressure of MC vapor at altitude for equal ppm concentrations) resulted in lower blood CHb levels. A statistical model was derived to explain variation in CHb levels for these three independent variables (r = 0.983). The data were applied to an equation assessing the impact of altitude, MC concentration and time on the potential oxygen carrying capacity (POCC) of blood. The POCC of HB in the blood was calculated using blood Hb, CHb levels, Hb oxygen saturation (based on the blood pO[sub 2] and the oxygen dissociation curve for rats), and oxygen binding potential of Hb. It was determined for the altitudes and MC concentrations used, polycythemia associated with increased altitude had a greater impact on POCC than decreased pO[sub 2]. A regression equation was derived modeling variation in POCC of blood for the three independent variables (r = 0.995). This study demonstrated that altitude affects airborne ppm MC concentrations. This ultimately impacts CHb levels and oxygen carrying capacity of the blood. These finding indicate that occupationally acceptable ppm MC exposure levels at altitude do need barometric pressure correction.

  11. Promotion of Softening and Ethylene Synthesis in Bartlett Pears by 3-Methylene Oxindole 1

    PubMed Central

    Frenkel, Chaim; Haddon, Virginia R.; Smallheer, Joanne M.

    1975-01-01

    A purified preparation of 3-methylene oxindole (3-MeOx) was applied to Bartlett pears (Lyrus communis) by vacuum infiltration. The infiltrated fruit were kept at room temperature at atmospheric or at one-twentieth of an atmospheric tension. The rate of softening was markedly enhanced by the application of 0.1 and 1 μm 3-MeOx. At 10 μm 3-MeOx the promotive effect of the compound was diminished. All the employed concentrations of 3-MeOx exceeded the effect of applied ethylene. The enhancement of softening in fruit kept under hypobaric conditions suggests that the action of 3-MeOx is a direct one and not an indirect ethylene effect. 3-MeOx also showed stimulation in the onset of ethylene synthesis, shortening the time required to obtain the peak in ethylene synthesis from 5 days by the control to 3 days by 0.1 μm and 2 days by 1 μm of the applied compound. As with softening, 3-MeOx at 10 μm diminished the rate of ethylene synthesis. The results suggest that 3-MeOx could function as a senescence promoter in fruit. Also, since auxins retard ripening while 3-MeOx promotes ripening, the action of 3-MeOx may be considered as that of an auxin antagonist. The occurrence and the mode of action of 3-MeOx as a possible senescence factor in fruit are discussed. PMID:16659363

  12. Electrode erosion during submerged arc treatment of methylene blue water solution

    NASA Astrophysics Data System (ADS)

    Parkansky, Naum; Yakubov, Violetta; Beilis, Isak I.; Boxman, Raymond L.; Berkh, Olga

    2015-06-01

    Low voltage, low energy submerged pulsed arcs with a pulse repetition rate of 100 Hz, energy of 48 mJ and duration of 20 μs were used to determine the electrode erosion rate during treatment of 10 mg l-1 methylene blue (MB) dissolved in 40 ml of deionized water, with and without the addition of 0.5% H2O2. Anode/cathode pairs of Fe/Fe, Ti/Ti, Cu/Cu, Cu/Fe, Fe/Cu, Ti/Fe, Fe/Ti, Cu/Ti and Ti/Cu were used. Smaller cathode erosion was measured, in the solutions without H2O2, with copper cathodes than with other cathodes. Smaller anode erosion in the same conditions was demonstrated by using pairs with a Ti anode than with other anodes and larger erosion was found for Cu anodes. By adding H2O2 to the treated solution, smaller cathode erosion was measured by using pairs with a Ti cathode than with other cathodes and larger rates were measured for Fe cathodes. The largest anode erosion was observed for a Cu anode. The erosion of the anode and cathode depends on material combination of the electrode pairs, i.e. on the thermo physical properties of the electrode materials. The correlations of anode/cathode erosion ratio (Ga/Gc) with ratio (qam/qcm) for various electrode materials were found, where qam and qcm are heat fluxes in the body of the anode and cathode, respectively. The experimental data were fitted by curves described with equation Ga/Gc =A(qa/qc)-b where A and b are experimental constants.

  13. A prospective study on sentinel lymph node biopsy in early oral cancers using methylene blue dye alone.

    PubMed

    Ramamurthy, Rajaraman; Kottayasamy Seenivasagam, Rajkumar; Shanmugam, Subbiah; Palanivelu, Kathirvelkumaran

    2014-09-01

    Sentinel Lymph Node (SLN) biopsy using a combination of radioisotopes and blue dyes have a good accuracy rate in predicting subclinical neck nodal metastases in head and neck cancers. However, the limited availability of lymphoscintigraphy facilities in India requires exploration of alternative methods of SLN detection. We evaluated the feasibility of using methylene blue dye alone in detecting SLN in cN0 early oral cancers. 32 patients with cN0 early (T1, T2) oral squamous cell cancers underwent SLN biopsy using peri tumoural methylene blue dye injection. Blue dye stained (SLN) nodes were sent for frozen section analyses. Patients who had microscopic metastases in SLN underwent modified radical neck dissections and the rest underwent selective neck dissections. Paraffin sections and IHC studies were done on all nodes. SLN was identified in 29 patients (Identification rate = 90.6 %) of which SLN was positive for metastases on frozen section in 5 patients. The sensitivity, specificity and NPV of SLN with frozen section were 80 %, 95.8 % and 95.8 % respectively. IHC with cytokeratins increased the sensitivity (100 %) and NPV (100 %) at the loss of specificity (87.5 %). Methylene blue dye alone can be successfully used for SLN identification in early oral cancers with a good accuracy and sensitivity. This method will be of use especially in resource limited countries and centres where nuclear medicine facilities are not widely available. However, it has to be validated by larger randomised multi institutional trials for wider applicability. Immunohistochemistry increases the sensitivity and negative predictive value of SLN but its applicability in real time decision making is limited.

  14. Experimental and theoretical vibrational study of methylene bis(thiocyanate), CH2(SCN)2. A comparison with thiocyanogen, (SCN)2

    NASA Astrophysics Data System (ADS)

    Fernández, L. E.; Gómez, A. A.; Tótaro, R. M.; Coronel, A. C.; Varetti, E. L.

    2013-06-01

    The infrared and Raman spectra of methylene bis(thiocyanate), CH2(SCN)2, were obtained. The observed bands were assigned to the different normal modes of vibration using the results of a DFT calculation of the molecular vibrational properties. These results and the experimental data were used to define a Scaled Quantum Mechanics force field for the molecule. A similar treatment was applied to the thiocyanogen molecule, (SCN)2, for which the experimental frequencies were already reported in the literature. The sets of internal force constants for both molecules show very similar values.

  15. Sandwichlike magnesium silicate/reduced graphene oxide nanocomposite for enhanced Pb²⁺ and methylene blue adsorption.

    PubMed

    Gui, Chen-Xi; Wang, Qian-Qian; Hao, Shu-Meng; Qu, Jin; Huang, Pei-Pei; Cao, Chang-Yan; Song, Wei-Guo; Yu, Zhong-Zhen

    2014-08-27

    A sandwichlike magnesium silicate/reduced graphene oxide nanocomposite (MgSi/RGO) with high adsorption efficiency of organic dye and lead ion was synthesized by a hydrothermal approach. MgSi nanopetals were formed in situ on both sides of RGO sheets. The nanocomposite with good dispersion of nanopetals exhibits a high specific surface area of 450 m(2)/g and a good mass transportation property. Compared to MgSi and RGO, the mechanical stability and adsorption capacity of the nanocomposite is significantly improved due to the synergistic effect. The maximum adsorption capacities for methylene blue and lead ion are 433 and 416 mg/g, respectively. PMID:25073122

  16. [Methylene blue as a supressor of the genotoxic effect of ultraviolet radiation with a wavelength of 300-400 nm].

    PubMed

    Chistiakov, V A; Sazykina, M A; Kolenko, M A; Cherviakov, G G; Usatov, A V

    2009-03-01

    Ultraviolet radiation with a wavelength of 300-400 nm is characteristic of sunlight at the earth surface and causes DNA damage mediated by energy transfer to O2 with the transformation of the latter in the singlet state. In connection with this, scavengers of reactive oxygen species (ROSs) are potential protectors against the genotoxic effect of this kind of radiation. It was found that the methylene blue dye at doses differing by several orders of magnitude from those that are toxic for humans is able to suppress completely the SOS response induced by UV with a wavelength of 300--400 nm in Escherichia coli.

  17. Dermal and inhalation exposure to methylene bisphenyl isocyanate (MDI) in iron foundry workers.

    PubMed

    Liljelind, I; Norberg, C; Egelrud, L; Westberg, H; Eriksson, K; Nylander-French, L A

    2010-01-01

    Diisocyanates are a group of chemically reactive agents, which are used in the production of coatings, adhesives, polyurethane foams, and parts for the automotive industry and as curing agents for cores in the foundry industry. Dermal and inhalation exposure to methylene bisphenyl isocyanate (MDI) is associated with respiratory sensitization and occupational asthma. However, limited research has been performed on the quantitative evaluation of dermal and inhalation exposure to MDI in occupationally exposed workers. The objective of this research was to quantify dermal and inhalation exposure levels in iron foundry workers. Workers involved in mechanized moulding and mechanized production of cores were monitored: 12 core makers, 2 core-sand preparers, and 5 core installers. Personal breathing-zone levels of MDI were measured using impregnated filter sampling. Dermal exposure to MDI was measured using a tape-strip technique. Three or five consecutive tape-strip samples were collected from five exposed skin areas (right and left forefingers, left and right wrists, and forehead). The average personal air concentration was 0.55 microg m(-3), 50-fold lower than the Swedish occupational exposure limit of 30 microg m(-3). The core makers had an average exposure of 0.77 microg m(-3), which was not significantly different from core installers' and core-sand preparers' average exposure of 0.16 microg m(-3) (P = 0.059). Three core makers had a 10-fold higher inhalation exposure than the other core makers. The core makers' mean dermal exposure at different skin sites varied from 0.13 to 0.34 microg while the two other groups' exposure ranged from 0.006 to 0.062 microg. No significant difference was observed in the MDI levels between the skin sites in a pairwise comparison, except for left forefinger compared to left and right wrist (P < 0.05). In addition, quantifiable but decreasing levels of MDI were observed in the consecutive tape strip per site indicating MDI penetration

  18. Study of epigenetic properties of Poly(HexaMethylene Biguanide) hydrochloride (PHMB).

    PubMed

    Creppy, Edmond E; Diallo, Aboudoulatif; Moukha, Serge; Eklu-Gadegbeku, Christophe; Cros, Daniel

    2014-08-08

    Poly(HexaMethylene Biguanide) hydrochloride (PHMB) CAS No. [32289-58-0] is a particularly effective member of the biguanides antiseptic chemical group, and has been in use since the early fifties in numerous applications. It has been proposed that PHMB be classified as a category 3 carcinogen although PHMB is not genotoxic. It has been hypothesized that PHMB may have epigenetic properties effects, including non-genotoxic modifications of DNA bases, DNA methylation and mitogenic cytokine production. These properties have been assessed in vitro using 3 cell types: Caco-2 cells (from a human colon adenocarcinoma) with a non-functional p53 gene. (∆p53: mut p53), N2-A (Neuro-2A cells, mouse neural cells), the brain being a possible target organ in rodents and HepG2 cells (human hepatocellular carcinoma) with functional p53 gene. From the concentration 1 µg/mL up to 20 µg/mL of PHMB, no effect was observed, either growth stimulation or inhibition. Viability testing using neutral red led to an IC 50 of 20-25 µg/mL after treatment with PHMB for 3 h, whereas the MTT test led to IC50 values of 80 µg/mL, 160 µg/mL and 160 µg/mL respectively for HepG2 cells, Neuro-2A cells and Caco-2 cells. PHMB does not induce significant oxidative stress (production of MDA or lipoperoxidation, nor does it induce hydroxylation of DNA (8-OH-dG) and/or its hypermethylation (m5dC), the latter being strongly implicated in DNA replication and regulation and cell division. PHMB does not induce significant production of mitogenic cytokines such as TNF-α (tumor necrosis factor), interleukins (IL-1 alpha), and the transcription factor nuclear factor kappa B (NF-κB) which can cause either apoptosis or stimulate the growth of transformed cells or tumors. Instead, from concentrations of 20 to 100 µg/mL, PHMB kills cells of all types in less than 3 h. The expression of genes involved in the mechanisms of cell death induced by PHMB, including p53, the pro apoptotic gene bax and others, the anti

  19. Dermal and inhalation exposure to methylene bisphenyl isocyanate (MDI) in iron foundry workers.

    PubMed

    Liljelind, I; Norberg, C; Egelrud, L; Westberg, H; Eriksson, K; Nylander-French, L A

    2010-01-01

    Diisocyanates are a group of chemically reactive agents, which are used in the production of coatings, adhesives, polyurethane foams, and parts for the automotive industry and as curing agents for cores in the foundry industry. Dermal and inhalation exposure to methylene bisphenyl isocyanate (MDI) is associated with respiratory sensitization and occupational asthma. However, limited research has been performed on the quantitative evaluation of dermal and inhalation exposure to MDI in occupationally exposed workers. The objective of this research was to quantify dermal and inhalation exposure levels in iron foundry workers. Workers involved in mechanized moulding and mechanized production of cores were monitored: 12 core makers, 2 core-sand preparers, and 5 core installers. Personal breathing-zone levels of MDI were measured using impregnated filter sampling. Dermal exposure to MDI was measured using a tape-strip technique. Three or five consecutive tape-strip samples were collected from five exposed skin areas (right and left forefingers, left and right wrists, and forehead). The average personal air concentration was 0.55 microg m(-3), 50-fold lower than the Swedish occupational exposure limit of 30 microg m(-3). The core makers had an average exposure of 0.77 microg m(-3), which was not significantly different from core installers' and core-sand preparers' average exposure of 0.16 microg m(-3) (P = 0.059). Three core makers had a 10-fold higher inhalation exposure than the other core makers. The core makers' mean dermal exposure at different skin sites varied from 0.13 to 0.34 microg while the two other groups' exposure ranged from 0.006 to 0.062 microg. No significant difference was observed in the MDI levels between the skin sites in a pairwise comparison, except for left forefinger compared to left and right wrist (P < 0.05). In addition, quantifiable but decreasing levels of MDI were observed in the consecutive tape strip per site indicating MDI penetration

  20. Nucleotide excision repair activity on DNA damage induced by photoactivated methylene blue.

    PubMed

    Berra, Carolina Maria; de Oliveira, Carla Santos; Garcia, Camila Carrião Machado; Rocha, Clarissa Ribeiro Reily; Lerner, Letícia Koch; Lima, Leonardo Carmo de Andrade; Baptista, Maurício da Silva; Menck, Carlos Frederico Martins

    2013-08-01

    The nucleotide excision repair (NER) mechanism is well known to be involved in the removal of UV-induced lesions. Nevertheless, the involvement of this pathway in the repair of lesions generated after DNA oxidation remains controversial. The effects of visible-light-excited methylene blue (MB), known to generate reactive oxygen species (ROS), were examined directly in xeroderma pigmentosum (XP)-A and XP-C NER-deficient human fibroblasts. Initially, MB was confirmed as being incorporated in similar amounts by the cells and that its photoexcitation induces the generation of (1)O2 within cells. The analysis of cell survival indicated that NER-deficient cells were hypersensitive to photoactivated MB. This sensitivity was confirmed with cells silenced for the XPC gene and by host-cell reactivation (HCR) of plasmid exposed to the photosensitizing effects of photoexcited MB. The sensitivity detected by HCR was restored in complemented cells, confirming the participation of XPA and XPC proteins in the repair of DNA lesions induced by photosensitized MB. Furthermore, DNA damage (single- and double-strand breaks and alkali-sensitive sites) was observed in the nuclei of treated cells by alkaline comet assay, with higher frequency of lesions in NER-deficient than in NER-proficient cells. Likewise, NER-deficient cells also presented more γ-H2AX-stained nuclei and G2/M arrest after photoactivated MB treatment, probably as a consequence of DNA damage response. Notwithstanding, the kinetics of both alkali- and FPG-sensitive sites repair were similar among cells, thereby demonstrating not only that MB photoexcitation generates nuclear DNA damage, but also that the removal of these lesions is NER-independent. Therefore, this work provides further evidence that XPA and XPC proteins have specific roles in cell protection and repair/tolerance of ROS-induced DNA damage. Moreover, as XPC-deficient patients do not present neurodegeneration, premature aging, or developmental clinical

  1. Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation.

    PubMed

    Altenor, Sandro; Carene, Betty; Emmanuel, Evens; Lambert, Jacques; Ehrhardt, Jean-Jacques; Gaspard, Sarra

    2009-06-15

    Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, X(P) (gH(3)PO(4)/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000 m(2)/g) and high pore volume (up to 1.19 cm(3)/g) can be obtained. The surface chemical properties of these ACs were investigated by X-ray photoelectron spectroscopy (XPS) and Boehm titration. Their textural and chemical characteristics were compared to those of an AC sample obtained by steam activation of vetiver roots. Classical molecules used for characterizing liquid phase adsorption, phenol and methylene blue (MB), were used. Adsorption kinetics of MB and phenol have been studied using commonly used kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the intraparticle diffusion model and as well the fractal, BWS (Brouers, Weron and Sotolongo) kinetic equation. The correlation coefficients (R(2)) and the normalized standard deviation Deltaq (%) were determined showing globally, that the recently derived fractal kinetic equation could best describe the adsorption kinetics for the adsorbates tested here, indicating a complex adsorption mechanism. The experimental adsorption isotherms of these molecules on the activated carbon were as well analysed using four isotherms: the classical Freundlich, Langmuir, Redlich-Peterson equations, but as well the newly published deformed Weibull Brouers-Sotolongo isotherm. The results obtained from the application of the equations show that the best fits were achieved with the Brouers-Sotolongo equation and with the Redlich-Peterson equation. Influence of surface functional groups towards MB adsorption is as well studied using various ACs prepared from vetiver roots and sugar cane bagasse. Opposite effects governing MB

  2. Influence of metal oxides on the adsorption characteristics of PPy/metal oxides for Methylene Blue.

    PubMed

    Chen, Jie; Feng, Jiangtao; Yan, Wei

    2016-08-01

    In this paper, the pure PPy and PPy/metal oxide composites including PPy/SiO2, PPy/Al2O3, and PPy/Fe3O4 as well as PPy coated commercial SiO2 and Al2O3 (PPy/SiO2(C) and PPy/Al2O3(C)) were successfully synthetized via chemical oxidative polymerization in acid aqueous medium to investigate the influence of metal oxides on adsorption capacity and their adsorption characteristics for Methylene Blue (MB). The composites were characterized by Zeta potential analysis, BET analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The results indicate that the metal oxides have great impact on textural properties, morphology, Zeta potential and PPy polymerization on their surface, further influence the adsorption capacity of their composites. The PPy/Al2O3(C) composite owns the highest specific surface area, rougher surface and most PPy content, and show the highest monolayer adsorption capacity reaching 134.77mg/g. In the adsorption characteristic studies, isotherm investigation shows an affinity order of PPy/metal oxides of PPy/Al2O3(C)>PPy/Al2O3>PPy/SiO2(C)>PPy/SiO2>PPy/Fe3O4>PPy, stating the affinity between PPy and MB was greatly improved by metal oxide, and Al2O3 owns high affinity for MB, followed by SiO2 and Fe3O4. Kinetic data of the composites selected (PPy/SiO2(C), PPy/Al2O3(C) and PPy/Fe3O4) were described more appropriately by the pseudo-second-order model, and the order of K2 is PPy/Al2O3>PPy/SiO2>PPy/Fe3O4, further showing a fast adsorption and good affinity of PPy/Al2O3(C) for MB. The regeneration method by HCl-elution and NaOH-activation was available, and the composites selected still owned good adsorption and desorption efficiency after six adsorption-desorption cycles.

  3. Methylene-bis[(aminomethyl)phosphinic acids]: synthesis, acid-base and coordination properties.

    PubMed

    David, Tomáš; Procházková, Soňa; Havlíčková, Jana; Kotek, Jan; Kubíček, Vojtěch; Hermann, Petr; Lukeš, Ivan

    2013-02-21

    Three symmetrical methylene-bis[(aminomethyl)phosphinic acids] bearing different substituents on the central carbon atom, (NH(2)CH(2))PO(2)H-C(R(1))(R(2))-PO(2)H(CH(2)NH(2)) where R(1) = OH, R(2) = Me (H(2)L(1)), R(1) = OH, R(2) = Ph (H(2)L(2)) and R(1),R(2) = H (H(2)L(3)), were synthesized. Acid-base and complexing properties of the ligands were studied in solution as well as in the solid state. The ligands show unusually high basicity of the nitrogen atoms (log K(1) = 9.5-10, log K(2) = 8.5-9) if compared with simple (aminomethyl)phosphinic acids and, consequently, high stability constants of the complexes with studied divalent metal ions. The study showed the important role of the hydroxo group attached to the central carbon atom of the geminal bis(phosphinate) moiety. Deprotonation of the hydroxo group yields the alcoholate anion which tends to play the role of a bridging ligand and induces formation of polynuclear complexes. Solid-state structures of complexes [H(2)N=C(NH(2))(2)][Cu(2)(H(-1)L(2))(2)]CO(3)·10H(2)O and Li(2)[Co(4)(H(-1)L(1))(3)(OH)]·17.5H(2)O were determined by X-ray diffraction. The complexes show unexpected geometries forming dinuclear and cubane-like structures, respectively. The dinuclear copper(II) complex contains a bridging μ(2)-alcoholate group with the (-)O-P(=O)-CH(2)-NH(2) fragments of each ligand molecule chelated to the different central ion. In the cubane cobalt(II) complex, one μ(3)-hydroxide and three μ(3)-alcoholate anions are located in the cube vertices and both phosphinate groups of one ligand molecule are chelating the same cobalt(II) ion while each of its amino groups are bound to different neighbouring metal ions. All such three metal ions are bridged by the alcoholate group of a given ligand.

  4. Study of epigenetic properties of Poly(HexaMethylene Biguanide) hydrochloride (PHMB).

    PubMed

    Creppy, Edmond E; Diallo, Aboudoulatif; Moukha, Serge; Eklu-Gadegbeku, Christophe; Cros, Daniel

    2014-08-01

    Poly(HexaMethylene Biguanide) hydrochloride (PHMB) CAS No. [32289-58-0] is a particularly effective member of the biguanides antiseptic chemical group, and has been in use since the early fifties in numerous applications. It has been proposed that PHMB be classified as a category 3 carcinogen although PHMB is not genotoxic. It has been hypothesized that PHMB may have epigenetic properties effects, including non-genotoxic modifications of DNA bases, DNA methylation and mitogenic cytokine production. These properties have been assessed in vitro using 3 cell types: Caco-2 cells (from a human colon adenocarcinoma) with a non-functional p53 gene. (∆p53: mut p53), N2-A (Neuro-2A cells, mouse neural cells), the brain being a possible target organ in rodents and HepG2 cells (human hepatocellular carcinoma) with functional p53 gene. From the concentration 1 µg/mL up to 20 µg/mL of PHMB, no effect was observed, either growth stimulation or inhibition. Viability testing using neutral red led to an IC 50 of 20-25 µg/mL after treatment with PHMB for 3 h, whereas the MTT test led to IC50 values of 80 µg/mL, 160 µg/mL and 160 µg/mL respectively for HepG2 cells, Neuro-2A cells and Caco-2 cells. PHMB does not induce significant oxidative stress (production of MDA or lipoperoxidation, nor does it induce hydroxylation of DNA (8-OH-dG) and/or its hypermethylation (m5dC), the latter being strongly implicated in DNA replication and regulation and cell division. PHMB does not induce significant production of mitogenic cytokines such as TNF-α (tumor necrosis factor), interleukins (IL-1 alpha), and the transcription factor nuclear factor kappa B (NF-κB) which can cause either apoptosis or stimulate the growth of transformed cells or tumors. Instead, from concentrations of 20 to 100 µg/mL, PHMB kills cells of all types in less than 3 h. The expression of genes involved in the mechanisms of cell death induced by PHMB, including p53, the pro apoptotic gene bax and others, the anti

  5. Mechanism of cell destruction and cell protection during methylene-blue-induced PDT

    NASA Astrophysics Data System (ADS)

    Rueck, Angelika C.; Beck, G.; Heckelsmiller, K.; Knoedlsdorfer, U.; Genze, Felicitas; Orth, K.

    1999-02-01

    Methylene Blue (MB+) is a well-known dye in medicine and has been discussed as an easily applicable drug for the topical treatment in photodynamic therapy (PDT). MB+ can potentially be used as a redox indicator to detect the important redox reactions that are induced during PDT. MB+ induced PDT was successful in the intraluminal treatment of inoperable esophageal tumors and in the topical treatment of psoriasis. In order to improve the therapy, the reaction mechanism of MB+ was investigated in vivo by local injection of MB+ in a xenotransplanted subcutaneous tumor (adeno-carcinoma, G-3) in female nude mice. The MB+ preparation 'MB+1%' was applied both undiluted and diluted to 0.1% and 0.01% with isotonic sodium chloride. After an incubation period of 1 h, the tumors were irradiated at 662 nm. Treatment with 1% MB+ and subsequent irradiation with 100 J/cm2 led to complete tumor destruction in 79% of the treated animals. A decrease of the fluence rate from 100 mW/cm2 to 50 mW/cm2 significantly increased the phototoxic response, which was attributed to oxygen depletion but also to nonlinear redox reactions. In addition, fractionated light application with 15 s interruption intervals enhanced the effect. When 0.1% MB+ was used, complete tumor destruction was observed only in 10% of the treated animals. Below a relatively high threshold dose the therapeutic response was not significant. The efficiency of the therapy was correlated with nonlinear dynamics of MB+ on a subcellular level, using laser scanning microscopy. During MB+-PDT nonlinear redox- reactions were induced. This could be deduced from local fast changes of the MB+-fluorescence as well as the pH-value during irradiation of single cells. The light induced reaction of MB+ seems to be correlated with the nonlinear production of reactive oxygen species (ROS). As a consequence below a threshold dose the reducing ability of MB+ prevents tissue from oxidative damage. However, above this dose, as a point of no

  6. Influence of metal oxides on the adsorption characteristics of PPy/metal oxides for Methylene Blue.

    PubMed

    Chen, Jie; Feng, Jiangtao; Yan, Wei

    2016-08-01

    In this paper, the pure PPy and PPy/metal oxide composites including PPy/SiO2, PPy/Al2O3, and PPy/Fe3O4 as well as PPy coated commercial SiO2 and Al2O3 (PPy/SiO2(C) and PPy/Al2O3(C)) were successfully synthetized via chemical oxidative polymerization in acid aqueous medium to investigate the influence of metal oxides on adsorption capacity and their adsorption characteristics for Methylene Blue (MB). The composites were characterized by Zeta potential analysis, BET analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The results indicate that the metal oxides have great impact on textural properties, morphology, Zeta potential and PPy polymerization on their surface, further influence the adsorption capacity of their composites. The PPy/Al2O3(C) composite owns the highest specific surface area, rougher surface and most PPy content, and show the highest monolayer adsorption capacity reaching 134.77mg/g. In the adsorption characteristic studies, isotherm investigation shows an affinity order of PPy/metal oxides of PPy/Al2O3(C)>PPy/Al2O3>PPy/SiO2(C)>PPy/SiO2>PPy/Fe3O4>PPy, stating the affinity between PPy and MB was greatly improved by metal oxide, and Al2O3 owns high affinity for MB, followed by SiO2 and Fe3O4. Kinetic data of the composites selected (PPy/SiO2(C), PPy/Al2O3(C) and PPy/Fe3O4) were described more appropriately by the pseudo-second-order model, and the order of K2 is PPy/Al2O3>PPy/SiO2>PPy/Fe3O4, further showing a fast adsorption and good affinity of PPy/Al2O3(C) for MB. The regeneration method by HCl-elution and NaOH-activation was available, and the composites selected still owned good adsorption and desorption efficiency after six adsorption-desorption cycles. PMID:27149689

  7. Quantitation of 4,4′-methylene diphenyl diisocyanate human serum albumin adducts

    PubMed Central

    Luna, Leah G.; Green, Brett J.; Zhang, Fagen; Arnold, Scott M.; Siegel, Paul D.; Bartels, Michael J.

    2016-01-01

    4,4′-Methylene diphenyl diisocyanate (herein 4,4′-MDI) is used in the production of polyurethane foams, elastomers, coatings, adhesives and the like for a wide range of commercial products. Occupational exposure to MDI levels above current airborne exposure limits can elicit immune mediated hypersensitivity reactions such as occupational asthma in sensitive individuals. To accurately determine exposure, there has been increasing interest in developing analytical methods to measure internal biomarkers of exposure to MDI. Previous investigators have reported methodologies for measuring MDI diamine metabolites and MDI-Lysine (4,4′-MDI-Lys) adducts. The purpose of this study was to develop and validate an ultra performance liquid chromatography isotope dilution tandem mass spectrometry (UPLC-ID/MS/MS) quantitation method via a signature peptide approach to enable biomonitoring of 4,4′-MDI adducted to human serum albumin (HSA) in plasma. A murine, anti-4,4′-MDI monoclonal IgM antibody was bound to magnetic beads and utilized for enrichment of the MDI adducted HSA. Following enrichment, trypsin digestion was performed to generate the expected 414 site (primary site of adduction) 4,4′-MDI-adducted HSA signature peptide that was quantified by UPLC-ID/MS/MS. An Agilent 6530 UPLC/quadrupole time of flight MS (QTOF) system was utilized for intact adducted protein analysis and an Agilent 6490 UPLC/MS/MS system operated in multiple reaction monitoring (MRM) mode was utilized for quantification of the adducted signature peptide biomarker both for in chemico and worker serum samples. Worker serum samples were initially screened utilizing the previously developed 4,4′-MDI-Lys amino acid method and results showed that 12 samples were identified as quantifiable for 4,4′-MDI-Lys adducts. The signature peptide adduct approach was applied to the 12 worker samples identified as quantifiable for 4,4′-MDI-Lys adducts. Results indicated no positive results were obtained

  8. Effects of feeding diets containing bacitracin methylene disalicylate to heat-stressed finishing pigs.

    PubMed

    Song, R; Foster, D N; Shurson, G C

    2011-06-01

    The objective of this study was to evaluate the effects of heat stress and dietary bacitracin methylene disalicylate (BMD) on growth performance, carcass characteristics, and immunological responses in finishing pigs. Four groups of 32 finishing pigs (n = 128) with initial BW between 80 to 90 kg were used. Pigs were fed a corn-soybean meal-distillers grains-based control or BMD (31.5 mg/kg) diet for a 14-d adaptation period at the thermal neutral temperature (23°C), and continued to be fed their respective diets when exposed to a constant temperature (23°C) or a cyclical heat stress environment (37°C from 1000 to 1900 h and 27°C from 1900 to 1000 h) for a 28-d experimental period. Each group of pigs was housed in 4 rooms, with 2 pens/room and 4 pigs/pen. Saliva samples from each pig were collected on d -1 (initial baseline), 1, 13, and 27 for cortisol analysis. Concentrations of haptoglobin, IL-1β, and tumor necrosis factor-α were determined in serum samples on d -1, 1, 13, and 27. Pigs exposed to heat stress had 31% less ADG (P < 0.001), 23% less ADFI (P < 0.001), 9% less G:F (P < 0.001), and 34% greater average daily water intake (P = 0.03) than those in the non-heat-stress conditions. Dietary BMD tended to reduce ADG (P < 0.07) compared with the control (0.66 vs. 0.73 kg/d, respectively). Heat stress increased (P < 0.05) saliva cortisol on d 1, but no effects were observed on subsequent days. Serum haptoglobin concentrations were greater (P < 0.05) in heat-stressed pigs on d 1, and concentrations tended to remain greater (P < 0.1) on d 13. Pigs fed the BMD diet tended to have a longer villus height (P = 0.07) in the duodenum and greater crypt depths in the duodenum (P = 0.09) and jejunum (P = 0.07). Heat-stressed pigs tended to have a decreased proportion of propionate (P = 0.08), greater acetate:propionate (P = 0.08), and a reduced proportion of valerate (P = 0.02) in the cecum. These results indicate that BMD did not counteract the negative effects of

  9. Continuous and Delayed Photohemolysis Sensitized With Methylene Blue and Iron Oxide Nanoparticles (Fe3O4)

    NASA Astrophysics Data System (ADS)

    AL-Akhras, M.-Ali; Aljarrah, Khaled; Albiss, Borhan; Alhaji Bala, Abba

    2015-10-01

    This research present the sensitization of methylene blue (MB), as a potential photodynamic therapy photo sensitizer which showed phototoxicity for many tumor cells in vitro incorporated with iron oxide nanoparticles (Fe3O4, IO-NP), which offer magnificent interaction both inside and outside the surface of biomolecules together with red blood cells (RBC's) with significant change in hemolysis process. The study investigated the sensitization of continuous photohemolysis (CPH) for MB and MB with IO-NP, delayed photohemolysis (DPH) at different irradiation temperature (Tirr). The photohemolysis rate for CPH at room temperature has a power dependence of 0.39 ± 0.05 with relative of steepness of 1.25 ± 0.02 and for different concentration of MB and power dependent of 0.15 ± 0.03 with relative steepness of 1.34 ± 0.01 for different MB and IO-NP. Logistic and Gompertz functions were applied as appropriate mathematical models to fit the collected experimental data for CPH and DPH respectively, and to calculate fractional photohemolysis rate with minimum errors. The Logistic function parameter; α, the hemolysis rate, increases with increasing concentrations of MB and decreases with increasing IO-NP concentrations in the presence of 6 μg/ml of MB. The parameter β the time required to reduce the maximum number of RBCs to one half of its value, decreases with increasing MB concentration and increases with increasing IO-NP concentrations in the presence of 6 pg/ml of MB. In DPH at different Tirr, the Gompertz parameter; a, fractional hemolysis ratio, is independent of temperature in both case MB and MB plus IO-NP, while the parameter; b, rate of fractional hemolysis change, increases with increasing Tirr, in both case MB and MB plus IO-NP. The apparent activation energy of colloid-osmotic hemolysis is 9.47±0.01 Kcal/mol with relative steepness of 1.31 ± 0.05 for different MB and 6.06±0.03 Kcal/mol with relative steepness of 1.41 ± 0.09 for MB with iron oxide. Our

  10. Methylene bromide chemistry and photochemistry on rutile TiO2(110)

    SciTech Connect

    Henderson, Michael A.; Robbins, Matthew D.

    2011-10-01

    The chemistry and photochemistry of methylene bromide (CD2Br2) on the rutile TiO2(110) surface was probed using temperature programmed desorption (TPD). CD2Br2 desorbed in three desorption states at 145, 160 and 250 K tentatively assigned to desorption from the multilayer, from an η1-CD2Br2 species and a bridging η2-CD2Br2 species, respectively. The latter two TPD states presumably involve binding of CD2Br2 molecules to the surface through Br coordination at five-coordinate Ti4+ surface sites. The 160 and 250 K TPD states saturated at coverages of 1.0 and 0.33 ML, respectively, where 1 ML is equivalent to the surface Ti4+ site density (5.2 × 1014 cm- 2). No thermal decomposition of CD2Br2 was observed on either the clean surface or with preadsorbed O2. UV irradiation of CD2Br2 on TiO2(110) resulted in predominately photodesorption, with trace amounts of photodecomposition evidenced in TPD. The rate of CD2Br2 photodesorption from TiO2(110) occurred with a low cross section (~ 2 × 10- 21 cm2) similar to that expected from direct optical excitation of CD2Br2. This observation suggests that charge carriers generated in TiO2(110) were no more effective in activating adsorbed CD2Br2 molecules than would be expected through direct molecular excitation. Finally, these findings suggest that photocatalytic destruction of halocarbons such as CD2Br2 on TiO2 may preferentially occur though indirect processes (such as OH radical attack) as opposed to direct electron transfer processes involving charge carriers generated in TiO2 by bandgap excitation.

  11. Hyperbaric oxygen therapy augments the photodynamic action of methylene blue against bacteria in vitro

    NASA Astrophysics Data System (ADS)

    Bisland, S. K.; Dadani, F. N.; Chien, C.; Wilson, B. C.

    2007-02-01

    Photodynamic therapy (PDT) entails the combination of photosensitizer and light to generate cytotoxic molecules that derive from molecular oxygen (O II). The presence of sufficient O II within the target tissues is critical to the efficiency of PDT. This study investigates the use of hyperbaric oxygen therapy in combination with PDT (HOTPDT) to augment the photodynamic action of methylene blue (MB) or 5-aminolevulinic acid (ALA) against gram positive and gram negative bacterial strains in vitro. Staphylococcus aureus or Pseudomonas aeruginosa were grown in trypticase soy broth as planktonic cultures (~10 8/mL) or as established biofilms in 48 well plates (3 days old) at 32°C. Dark toxicity and PDT response in the presence or absence of HOT (2 atmospheres, 100% O II for 30, 60 or 120 min) was established for both MB (0-0.1 mM) and ALA (0- 1 mM) for a range of incubation times. The number of surviving colonies (CFU/mL) was plotted for each treatment groups. Light treatments (5, 10, 20 or 30 J/cm2) were conducted using an array of halogen bulbs with a red filter providing 90% transmittance over 600-800 nm at 21 mW/cm2. HOT increased the dark toxicity of MB (30 min, 0.1 mM) from < 0.2 log cell kill to 0.5 log cell kill. Dark toxicity of ALA (4 hr, 1 mM) was negligible and did not increase with HOT. For non-dark toxic concentrations of MB or ALA, (0.05 mM and 1 mM respectively) HOT-PDT enhanced the antimicrobial effect of MB against Staphylococcus aureus in culture by >1 and >2 logs of cell kill (CFU/mL) at 5 and 10 J/cm2 light dose respectively as compared to PDT alone. HOT-PDT also increased the anti-microbial effects of MB against Staphylococcus aureus biofilms compared to PDT, albeit less so (> 2 logs) following 10 J/cm2 light dose. Anti-microbial effects of PDT using ALA were not significant for either strain with or without HOT. These data suggest that HOTPDT may be useful for improving the PDT treatment of bacterial infections.

  12. Methylene migration and coupling on a non-reducible metal oxide: The reaction of dichloromethane on stoichiometric α-Cr2O3(0001)

    DOE PAGES

    Dong, Yujung; Brooks, John D.; Chen, Tsung-Liang; Mullins, David R.; Cox, David F.

    2014-09-17

    The reaction of CH2Cl2 over the nearly-stoichiometric α-Cr2O3(0001) surface produces gas phase ethylene, methane and surface chlorine adatoms. The reaction is initiated by the decomposition of CH2Cl2 into surface methylene and chlorine. Photoemission indicates that surface cations are the preferred binding sites for both methylene and chlorine adatoms. Two reaction channels are observed for methylene coupling to ethylene in temperature-programmed desorption (TPD). A desorption-limited, low-temperature route is attributed to two methylenes bound at a single site. The majority of ethylene is produced by a reaction-limited process involving surface migration (diffusion) of methylene as the rate-limiting step. DFT calculations indicate themore » surface diffusion mechanism is mediated by surface oxygen anions. The source of hydrogen for methane formation is adsorbed background water. Chlorine adatoms produced by the dissociation of CH2Cl2 deactivate the surface by simple site-blocking of surface Cr3+ sites. Finally, a comparison of experiment and theory shows that DFT provides a better description of the surface chemistry of the carbene intermediate than DFT+U using reported parameters for a best representation of the bulk electronic properties of α-Cr2O3.« less

  13. Dissimilarities between methylene blue and cyanide on relaxation and cyclic GMP formation in endothelium-intact intrapulmonary artery caused by nitrogen oxide-containing vasodilators and acetylcholine

    SciTech Connect

    Ignarro, L.J.; Harbison, R.G.; Wood, K.S.; Kadowitz, P.J.

    1986-01-01

    The objective of the present study was to ascertain whether cyanide shares the properties of methylene blue as a selective inhibitor of vascular smooth muscle relaxation elicited by agents that stimulate the formation of cyclic GMP. Experiments were performed with endothelium-intact rings prepared from bovine intrapulmonary artery. Methylene blue, a good inhibitor of soluble guanylate cyclase, antagonized both arterial relaxation and cyclic GMP accumulation in response to sodium nitroprusside, glyceryl trinitrate, S-nitroso-N-acetylpenicillamine and acetylcholine. In contrast, cyanide inhibited only the responses to sodium nitroprusside. Increasing concentrations of methylene blue depressed resting arterial levels of cyclic GMP and caused slowly developing but marked contractions whereas cyanide was without effect. Contractile responses to phenylephrine, potassium and U46619 were potentiated by methylene blue but not by cyanide. Preincubation of dilute solutions of cyanide containing sodium nitroprusside in oxygenated Krebs' buffer at 37 degrees C for 15 min before addition to bath chambers depressed relaxation and cyclic GMP accumulation caused by sodium nitroprusside markedly. Similar treatment of glyceryl trinitrate, however, failed to alter its effects in arterial rings. A chemical inactivation of sodium nitroprusside by cyanide appears to account for the specific inhibitory action of cyanide on arterial responses to sodium nitroprusside. This study indicates clearly that cyanide does not share the properties of methylene blue as an inhibitor of arterial relaxation elicited by vasodilators that stimulate cyclic GMP formation.

  14. Methylene migration and coupling on a non-reducible metal oxide: The reaction of dichloromethane on stoichiometric α-Cr2O3(0001)

    NASA Astrophysics Data System (ADS)

    Dong, Yujung; Brooks, John D.; Chen, Tsung-Liang; Mullins, David R.; Cox, David F.

    2015-02-01

    The reaction of CH2Cl2 over the nearly-stoichiometric α-Cr2O3(0001) surface produces gas phase ethylene, methane and surface chlorine adatoms. The reaction is initiated by the decomposition of CH2Cl2 into surface methylene and chlorine. Photoemission indicates that surface cations are the preferred binding sites for both methylene and chlorine adatoms. Two reaction channels are observed for methylene coupling to ethylene in temperature-programmed desorption (TPD). A desorption-limited, low-temperature route is attributed to two methylenes bound at a single site. The majority of ethylene is produced by a reaction-limited process involving surface migration (diffusion) of methylene as the rate-limiting step. DFT calculations indicate the surface diffusion mechanism is mediated by surface oxygen anions. The source of hydrogen for methane formation is adsorbed background water. Chlorine adatoms produced by the dissociation of CH2Cl2 deactivate the surface by simple site-blocking of surface Cr3 + sites. A comparison of experiment and theory shows that DFT provides a better description of the surface chemistry of the carbene intermediate than DFT+U using reported parameters for a best representation of the bulk electronic properties of α-Cr2O3.

  15. Design and Synthesis of Metal Complexes of (2E)-2-[(2E)-3-Phenylprop-2-en-1-ylidene]hydrazinecarbothioamide and Their Photocatalytic Degradation of Methylene Blue

    PubMed Central

    Krishna, P. Murali; Reddy, N. B. Gopal; Kottam, Nagaraju; Yallur, B. C.; Katreddi, Hussain Reddy

    2013-01-01

    The photocatalytic degradation has been considered to be an efficient process for the degradation of organic pollutants, which are present in the effluents released by industries. The photocatalytic bleaching of cationic dye methylene blue was carried out spectrometrically on irradiation of UV light using Cu(II), Ni(II), and Co(II) complexes of (2E)-2-[(2E)-3-phenylprop-2-en-1-ylidene]hydrazinecarbothioamide (HL). The effects of pH and metal ion were studied on the efficiency of the reaction. Cu(II) complex shows better catalytic activity and the highest percentage degradation (~88.8%) of methylene blue was observed at pH 12. A tentative mechanism has also been proposed for the photocatalytic degradation of methylene blue. PMID:24363623

  16. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of methylene blue active substances by spectrophotometry

    USGS Publications Warehouse

    Burkhardt, Mark R.; Cinotto, Pete J.; Frahm, Galen W.; Woodworth, Mark T.; Pritt, Jeffrey W.

    1995-01-01

    A method for the determination of methylene blue active substances in whole-water samples by liquid-liquid extraction and spectrophotometric detection is described. Sulfate and sulfonate-based surfectants are reacted with methylene blue to form a blue-colored complex. The complex is extracted into chloroform, back-washed with an acidified phosphate-based buffer solution, and measured against external standards with a probe spectrophotometer. The method detection limt for routine analysis is 0.02 milligram per liter. The precision is plus/minus 10 percent relative standard deviation. The positive bias from nitrate and chloride and U.S. Geological Survey method O-3111-83 for methylene blue active substances is minized by adding a back-washing step.

  17. Preparation and characterization of poly(AA co PVP)/PGS composite and its application for methylene blue adsorption.

    PubMed

    Yang, Cai-xia; Lei, Lei; Zhou, Peng-xin; Zhang, Zhe; Lei, Zi-qiang

    2015-04-01

    Poly (AA co PVP)/PGS (PAPP) composite adsorbent was prepared by radical polymerization from Acrylic acid (AA), Polyvinylpyrrolidone (PVP) and Palygorskite (PGS), using N,N-methylenebisacrylamide (MBA) as cross-linker and potassium persulfate (KPS) as initiator. The PAPP was characterized with Fourier transform infrared (FT-IR), thermogravimetric analysis (TG), scanning electron microscope (SEM) and transmission electron microscopy (TEM). PAPP was used as adsorbent for the removal of methylene blue from aqueous solutions. The influences of pH, adsorption temperature and adsorption time on the adsorption properties of the composite to the dye were also investigated. Meanwhile, the adsorption rate data and adsorption equilibrium date were analyzed based on the pseudo-first-order and pseudo-second-order kinetic model, Langmuir and Freundlich isotherm models, respectively. The results indicating that the kinetic behavior better fit with the pseudo-second-order kinetic model. The maximum equilibrium adsorption capacity (q(m)) is 1815 mg/g at 289 K. The isotherm behavior can be explained by the Langmuir isotherm models. The activation energy was also evaluated for the removal of methylene blue onto PAPP. These results demonstrate that this composite material could be used as a good adsorbent for the removal of cationic dyes from wastewater. PMID:25540826

  18. Poly(amic acid)-modified biomass of baker's yeast for enhancement adsorption of methylene blue and basic magenta.

    PubMed

    Yu, Jun-xia; Li, Bu-hai; Sun, Xiao-mei; Yuan, Jun; Chi, Ru-an

    2010-03-01

    In this study, poly(amic acid)-modified biomass was prepared to improve the adsorption capacities for two cationic dyes, methylene blue and basic magenta. X-ray photoelectron spectroscopy and potentiometric titration demonstrated that a large number of imide, amine, and carboxyl groups were introduced on the biomass surface, and the concentrations of these functional groups were calculated to be 0.27, 1.08, and 1.08 mmol g(-1) by using the first derivative method. According to the Langmuir equation, the maximum uptake capacities (q(m)) for methylene blue and basic magenta were 680.3 and 353.4 mg g(-1), respectively, which were 13- and sevenfold than that obtained on the unmodified biomass. Adsorption kinetics study showed that the completion of the adsorption process needed only 40 min, which is faster than the common sorbent such as activated carbon and resin. Experimental results showed that pH and ionic strength had little effect on the capacity of the modified biomass, indicating that the modified biomass had good potential for practical use.

  19. A study on the adsorption of methylene blue onto gum ghatti/TiO2 nanoparticles-based hydrogel nanocomposite.

    PubMed

    Mittal, Hemant; Ray, Suprakas Sinha

    2016-07-01

    The objective of this work was to study the isotherm and kinetic models for the adsorption of methylene blue (MB) onto a TiO2 nanoparticle (TiO2NP)-containing hydrogel nanocomposite (HNC) of polyacrylamide-grafted gum ghatti (PAAm-g-Gg). The grafting of PAAm onto Gg was conducted using N,N'-methylene-bis-acrylamide (MBA) as a crosslinker, and different weight percentages of TiO2NPs were incorporated into the hydrogel matrix during the grafting reaction. The graft co-polymerization and the formation of the HNC were confirmed using FTIR, XRD, BET, SEM, TEM and EDS analyses. The adsorption of MB was studied in batch mode and it was found to be highly dependent on solution pH, ionic strength temperature and adsorbent loading. The MB-adsorption process followed the pseudo-second-order rate model and Langmuir adsorption isotherm with a maximum adsorption capacity of 1305.5mgg(-1). Thermodynamic studies revealed that the adsorption of MB onto the HNC surface was spontaneous, endothermic and through a process of physisorption. The results also showed that the HNC was much more effective for the adsorption of cationic dyes than anionic dyes, and it retained its original adsorption capacity for five successive cycles of adsorption-desorption. In conclusion, the hydrogel nanocomposite showed huge potential for remediating industrial wastewater polluted by toxic cationic dyes.

  20. Preparation and characterization of poly(AA co PVP)/PGS composite and its application for methylene blue adsorption.

    PubMed

    Yang, Cai-xia; Lei, Lei; Zhou, Peng-xin; Zhang, Zhe; Lei, Zi-qiang

    2015-04-01

    Poly (AA co PVP)/PGS (PAPP) composite adsorbent was prepared by radical polymerization from Acrylic acid (AA), Polyvinylpyrrolidone (PVP) and Palygorskite (PGS), using N,N-methylenebisacrylamide (MBA) as cross-linker and potassium persulfate (KPS) as initiator. The PAPP was characterized with Fourier transform infrared (FT-IR), thermogravimetric analysis (TG), scanning electron microscope (SEM) and transmission electron microscopy (TEM). PAPP was used as adsorbent for the removal of methylene blue from aqueous solutions. The influences of pH, adsorption temperature and adsorption time on the adsorption properties of the composite to the dye were also investigated. Meanwhile, the adsorption rate data and adsorption equilibrium date were analyzed based on the pseudo-first-order and pseudo-second-order kinetic model, Langmuir and Freundlich isotherm models, respectively. The results indicating that the kinetic behavior better fit with the pseudo-second-order kinetic model. The maximum equilibrium adsorption capacity (q(m)) is 1815 mg/g at 289 K. The isotherm behavior can be explained by the Langmuir isotherm models. The activation energy was also evaluated for the removal of methylene blue onto PAPP. These results demonstrate that this composite material could be used as a good adsorbent for the removal of cationic dyes from wastewater.

  1. Adsorption of methylene blue onto activated carbon produced from tea (Camellia sinensis L.) seed shells: kinetics, equilibrium, and thermodynamics studies.

    PubMed

    Gao, Jun-Jie; Qin, Ye-Bo; Zhou, Tao; Cao, Dong-Dong; Xu, Ping; Hochstetter, Danielle; Wang, Yue-Fei

    2013-07-01

    Tea (Camellia sinensis L.) seed shells, the main byproduct of the manufacture of tea seed oil, were used as precursors for the preparation of tea activated carbon (TAC) in the present study. A high yield (44.1%) of TAC was obtained from tea seed shells via a one-step chemical method using ZnCl2 as an agent. The Brunauer-Emmett-Teller (BET) surface area and the total pore volumes of the obtained TAC were found to be 1530.67 mg(2)/g and 0.7826 cm(3)/g, respectively. The equilibrium adsorption results were complied with Langmuir isotherm model and its maximum monolayer adsorption capacity was 324.7 mg/g for methylene blue. Adsorption kinetics studies indicated that the pseudo-second-order model yielded the best fit for the kinetic data. An intraparticle diffusion model suggested that the intraparticle diffusion was not the only rate-controlling step. Thermodynamics studies revealed the spontaneous and exothermic nature of the sorption process. These results indicate that tea seed shells could be utilized as a renewable resource to develop activated carbon which is a potential adsorbent for methylene blue.

  2. Adsorption of methylene blue onto activated carbon produced from tea (Camellia sinensis L.) seed shells: kinetics, equilibrium, and thermodynamics studies*

    PubMed Central

    Gao, Jun-jie; Qin, Ye-bo; Zhou, Tao; Cao, Dong-dong; Xu, Ping; Hochstetter, Danielle; Wang, Yue-fei

    2013-01-01

    Tea (Camellia sinensis L.) seed shells, the main byproduct of the manufacture of tea seed oil, were used as precursors for the preparation of tea activated carbon (TAC) in the present study. A high yield (44.1%) of TAC was obtained from tea seed shells via a one-step chemical method using ZnCl2 as an agent. The Brunauer-Emmett-Teller (BET) surface area and the total pore volumes of the obtained TAC were found to be 1 530.67 mg2/g and 0.782 6 cm3/g, respectively. The equilibrium adsorption results were complied with Langmuir isotherm model and its maximum monolayer adsorption capacity was 324.7 mg/g for methylene blue. Adsorption kinetics studies indicated that the pseudo-second-order model yielded the best fit for the kinetic data. An intraparticle diffusion model suggested that the intraparticle diffusion was not the only rate-controlling step. Thermodynamics studies revealed the spontaneous and exothermic nature of the sorption process. These results indicate that tea seed shells could be utilized as a renewable resource to develop activated carbon which is a potential adsorbent for methylene blue. PMID:23825151

  3. A study on the adsorption of methylene blue onto gum ghatti/TiO2 nanoparticles-based hydrogel nanocomposite.

    PubMed

    Mittal, Hemant; Ray, Suprakas Sinha

    2016-07-01

    The objective of this work was to study the isotherm and kinetic models for the adsorption of methylene blue (MB) onto a TiO2 nanoparticle (TiO2NP)-containing hydrogel nanocomposite (HNC) of polyacrylamide-grafted gum ghatti (PAAm-g-Gg). The grafting of PAAm onto Gg was conducted using N,N'-methylene-bis-acrylamide (MBA) as a crosslinker, and different weight percentages of TiO2NPs were incorporated into the hydrogel matrix during the grafting reaction. The graft co-polymerization and the formation of the HNC were confirmed using FTIR, XRD, BET, SEM, TEM and EDS analyses. The adsorption of MB was studied in batch mode and it was found to be highly dependent on solution pH, ionic strength temperature and adsorbent loading. The MB-adsorption process followed the pseudo-second-order rate model and Langmuir adsorption isotherm with a maximum adsorption capacity of 1305.5mgg(-1). Thermodynamic studies revealed that the adsorption of MB onto the HNC surface was spontaneous, endothermic and through a process of physisorption. The results also showed that the HNC was much more effective for the adsorption of cationic dyes than anionic dyes, and it retained its original adsorption capacity for five successive cycles of adsorption-desorption. In conclusion, the hydrogel nanocomposite showed huge potential for remediating industrial wastewater polluted by toxic cationic dyes. PMID:26997239

  4. Adsorptive removal and kinetics of methylene blue from aqueous solution using NiO/MCM-41 composite

    NASA Astrophysics Data System (ADS)

    Xiao, Xuechun; Zhang, Fei; Feng, Zhipeng; Deng, Shaojuan; Wang, Yude

    2015-01-01

    Highly ordered mesoporous material MCM-41 was synthesized from tetraethylorthosilicate (TEOS) as Si source and cetyltrimethylammonium bromide (CTAB) as template. Well-dispersed NiO nanoparticles were introduced into the highly ordered mesoporous MCM-41 by chemical precipitation method to prepare the highly ordered mesoporous NiO/MCM-41 composite. X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and high-resolution TEM (HRTEM), and nitrogen adsorption-desorption measurement were used to examine the morphology and the microstructure of the obtained composite. The morphological study clearly revealed that the synthesized NiO/MCM-41 composite has a highly ordered mesoporous structure with a specific surface area of 435.9 m2 g-1. A possible formation mechanism is preliminary proposed for the formation of the nanostructure. The adsorption performance of NiO/MCM-41 composite as an adsorbent was further demonstrated in the removal azo dyes of methyl orange (MO), Congo red (CR), methylene blue (MB) and rhodaming B (RB) under visible light irradiation and dark, respectively. The kinetics and mechanism of removal methylene blue were studied. The results show that NiO/MCM-41 composite has a good removal capacity for organic pollutant MB from the wastewater under the room temperature. Compared with MCM-41 and NiO nanoparticles, 54.2% and 100% higher removal rate were obtained by the NiO/MCM-41 composite.

  5. Methylene chloride intoxication in a furniture refinisher. A comparison of exposure estimates utilizing workplace air sampling and blood carboxyhemoglobin measurements

    SciTech Connect

    Shusterman, D.; Quinlan, P.; Lowengart, R.; Cone, J. )

    1990-05-01

    A 35-year-old furniture refinisher came to the occupational medicine clinic with complaints of upper respiratory irritation, fatigue, and lightheadedness occurring on a daily basis after using a methylene chloride-containing paint stripper. Determinations of blood carboxyhemoglobin (COHb) on three occasions showed an apparently linear elevation of COHb as a function of hours worked on the day of sampling. COHb levels predicted from spot industrial hygiene measurements were in close concordance with those observed in the patient, indicating the potential usefulness of COHb monitoring in estimating airborne exposure levels. Methylene chloride (or dichloromethane) is an organic solvent that has found wide use as a degreaser, paint remover, aerosol propellant, and a blowing agent for polyurethane foams, and as a solvent in food processing, photographic film production, and plastics manufacturing. Discovery of its unusual metabolic fate--conversion to carbon monoxide in vivo--has earned the compound a special place in the solvent toxicology literature. Demonstration of oncogenicity in experimental animals has occasioned a reconsideration of exposure limits, with emphasis upon stricter controls. In some workplaces, conditions prevail in which controls are inadequate to prevent even acute toxicity, much less long-term exposure risks.

  6. Preparation and characterization of Cu{sub 2}O-TiO{sub 2}: Efficient photocatalytic degradation of methylene blue

    SciTech Connect

    Xu Yuehua Liang Dahui; Liu Manle; Liu Dingzhong

    2008-12-01

    A series of copper-deposited titania were prepared by photoreduction method under irradiation with a 125-W high-pressure mercury lamp. From XPS and AES results, the deposited-copper formed Ti-O-Cu bond on the surface of TiO{sub 2}, and the Cu species on the surface of copper-deposited TiO{sub 2} can be identified as Cu(I). The photocatalytic degradation activity of methylene blue for the Cu{sub 2}O-TiO{sub 2} series increased with increasing Cu{sub 2}O-deposited content, and then decreased. The highest photocatalytic degradation activity of methylene blue was obtained for 0.16% Cu{sub 2}O-TiO{sub 2}. When copper-deposited content reached to 0.32%, the photocatalytic activity was lower than that of pure TiO{sub 2}. It is shown that Cu{sub 2}O on the surface of TiO{sub 2} can trap electrons from the TiO{sub 2} conduction band, and the electrons trapped on the Cu{sub 2}O-TiO{sub 2} site are subsequently transferred to the surrounding adsorbed O{sub 2}, thereby avoiding electron-hole recombination, and enhancing the photocatalytic activity. Excess copper loading may screen the photocatalyst from the UV source, so the photocatalytic activity diminishes with increasing Cu{sub 2}O.

  7. Methylene blue degradation by NaTaO3 sol-gel doped with Sm and La.

    PubMed

    Torres-Martínez, Leticia M; Cruz-López, Arquímedes; Juárez-Ramírez, Isaías; Meza-de la Rosa, Ma Elena

    2009-06-15

    In this work, NaTaO(3) compounds doped with 1M% of La and Sm, were prepared by the sol-gel (SG) method and solid state (SS) reaction; and tested as photocatalysts on the degradation of methylene blue (MB) under UV light. The structural characterization by X-ray powder diffraction revealed that the crystallization of the NaTaO(3) phase prepared by the sol-gel method started at 600 degrees C, reaching maximum crystallization at 800 degrees C. It was determined that the presence of Sm and La retard the crystallization of the NaTaO(3) phase. On the other hand, the compounds synthesized in this work showed particle sizes in the nanometric scale, as it was observed by scanning electron microscopy (SEM). The specific surface area of the compounds synthesized by the sol-gel method, showed values 4 times higher than those obtained by the solid state reaction, favoring their functional and photocatalytic performance in the methylene blue degradation. In addition, the best photocatalytic performance was shown by the NaTaO(3) doped with Sm and heated at 600 degrees C, having a half-life time of 65 min.

  8. Methylene blue degradation by NaTaO3 sol-gel doped with Sm and La.

    PubMed

    Torres-Martínez, Leticia M; Cruz-López, Arquímedes; Juárez-Ramírez, Isaías; Meza-de la Rosa, Ma Elena

    2009-06-15

    In this work, NaTaO(3) compounds doped with 1M% of La and Sm, were prepared by the sol-gel (SG) method and solid state (SS) reaction; and tested as photocatalysts on the degradation of methylene blue (MB) under UV light. The structural characterization by X-ray powder diffraction revealed that the crystallization of the NaTaO(3) phase prepared by the sol-gel method started at 600 degrees C, reaching maximum crystallization at 800 degrees C. It was determined that the presence of Sm and La retard the crystallization of the NaTaO(3) phase. On the other hand, the compounds synthesized in this work showed particle sizes in the nanometric scale, as it was observed by scanning electron microscopy (SEM). The specific surface area of the compounds synthesized by the sol-gel method, showed values 4 times higher than those obtained by the solid state reaction, favoring their functional and photocatalytic performance in the methylene blue degradation. In addition, the best photocatalytic performance was shown by the NaTaO(3) doped with Sm and heated at 600 degrees C, having a half-life time of 65 min. PMID:19042087

  9. A methylene blue-assisted technique for harvesting lymph nodes after radical surgery for gastric cancer: a prospective, randomized, controlled study.

    PubMed

    Aoyama, Toru; Fujikawa, Hirohito; Cho, Haruhiko; Ogata, Takashi; Shirai, Junya; Hayashi, Tsutomu; Rino, Yasushi; Masuda, Munetaka; Oba, Mari S; Morita, Satoshi; Yoshikawa, Takaki

    2015-02-01

    Harvesting lymph nodes (LNs) after gastrectomy is essential for accurate staging. This trial evaluated the efficiency and quality of a conventional method and a methylene blue-assisted method in a randomized manner. The key eligibility criteria were as follows: (i) histologically proven adenocarcinoma of the stomach; (ii) clinical stage I-III; (iii) R0 resection planned by gastrectomy with D1+ or D2 lymphadenectomy. The primary endpoint was the ratio of the pathologic number of harvested LNs per time (minutes) as an efficacy measure. The secondary endpoint was the number of harvested LNs, as a quality measure. Between August 2012 and December 2012, 60 patients were assigned to undergo treatment using the conventional method (n=29) and the methylene blue dye method (n=31). The baseline demographics were mostly well balanced between the 2 groups. The number of harvested LNs (mean±SD) was 33.6±11.9 in the conventional arm and 43.4±13.9 in the methylene blue arm (P=0.005). The ratio of the number of the harvested LNs per time was 1.12±0.46 LNs/min in the conventional arm and 1.49±0.59 LNs/min in the methylene blue arm (P=0.010). In the subgroup analyses, the quality and efficacy were both superior for the methylene blue dye method compared with the conventional method. The methylene blue technique is recommended for harvesting LNs during gastric cancer surgery on the basis of both the quality and efficacy.

  10. Comparison of raw and modified activated carbon and rice industry wastes for methylene blue sorption

    NASA Astrophysics Data System (ADS)

    Befani, Maria; Manariotis, Ioannis D.; Karapanagioti, Hrissi K.; Quintero, César E.

    2015-04-01

    In Argentina the average paddy rice production was 1.3x106 tn/year in the last decade. Entre Ríos province (E.R.) accounts for 60% of national milling, resulting in a significant accumulation of waste in the local environment; husk and ashes are used as fuel in drying grain plants. The use of rice wastes, as low-cost sorbents for the removal of synthetic dyes and other contaminants may be a sustainable option. The aim of this work is the investigation of the removal capacity of methylene blue (MB) from aqueous solutions using: (a) rice husk from a rice mill located in E.R. of size between 0.15 to 1.18 mm (RH2), (b) ash from rice husk burned at 800°C in oven for the grain drying unit of the rice mill (RHA800), and (c) biochar obtained from pyrolysis of RH2 material at 850°C (RHA4). Commercial activated carbon (AC), which is a porous material of high sorption capacity, was also used to compare its sorption capacity with the rice husk products. Furthermore, the incorporation of iron in the AC was studied using two different AC/Fe weight-by-weight ratios (AC-Fe and AC-0.5 Fe). The solution pH effect was studied in a range from 2 to 6.9. The maximal MB removal was achieved at pH of 6.8 to 6.9 for all materials studied, and at pH of 6.4 for AC. Kinetic experiments were conducted for a period of 48 h at pH 7 and C0 = 50 mg MB/L. Equilibrium was reached after 24 h and the adsorption capacity was 156, 104, 90, 79, 26, and 9 mg/g for AC, AC-Fe, AC-0.5 Fe, RHA4, RH2 and RHA800, respectively. The pseudo-second-order model expressed better the sorption kinetics of MB for all adsorbent materials. The AC-based materials presented better performance. The experimental data were fitted with the Freundlich and Langmuir isotherm models. The Langmuir model fits the data better in all cases. The maximum adsorption capacity was 238, 125, 92, 91, 46 and 9 mg/g for AC, AC-Fe, AC-0.5 Fe, RHA4, RH2 and RHA800, respectively. Agricultural wastes can be considered low-cost sorbents, but

  11. Suitability of the methylene blue test for determination of cation exchange capacity of clay minerals related to ammonium acetate method

    NASA Astrophysics Data System (ADS)

    Milošević, Maja; Logar, Mihovil; Dojčinović, Biljana; Erić, Suzana

    2015-04-01

    Cation exchange capacity (CEC) represents one of the most important parameters of clay minerals which reflects their ability to exchange cations with liquid phases in near contact. Measurement of CEC is used for characterizing sample plasticity, adsorbing and swelling properties which later define their usage in industrial purposes. Several methods have been developed over the years for determination of layer charge, charge density, charge distribution, etc. and have been published in numerous papers (Czimerova et al., 2006; Yukselen and Kaya, 2008). The main goal of present study is comparison of suitability of more recent method - methylene blue test in regard to older method - ammonium acetate for determination of CEC. For this study, we selected one montmorillonite clay (Bogovina, Serbia) and two mainly kaolinite clays (Miličinica, Serbia). Chemicals used for CEC determinations were solution of methylene blue (MB)(14*10-6M/ml) and ammonium acetate (AA) solution (1M). The obtained results are showing generally lower values in case of MB method. The main difference is due to molecular aggregation of MB on the clay surface. AA method is highly sensitive to the presence of CaO. Release of Ca ion from the sample into the solution can limit the saturation of exchange sites by the ammonium ion. This is clearly visible in case of montmorillonite clay. Fe2+ and Mg ions are difficult to move by the ammonium ion because of their ion radius, but in case of MB molecule there is no such restriction in removing them from the exchange sites. MB solution, even in a low concentration (2*10-6M/ml), is showing preferable results in moving the ions from their positions which is already visible after adding a small quantity of solution (25cm3). Both MB-titration and MB-spot test yield similar results and are much simpler methods than AA and they also give other information such as specific surface area (external and internal) whereas AA method only provides information about

  12. SU-E-I-64: Transverse Relaxation Time in Methylene Protons of Non-Alcoholic Fatty Liver Disease Rats

    SciTech Connect

    Song, K-H; Lee, D-W; Choe, B-Y

    2015-06-15

    Purpose: The aim of this study was to evaluate transverse relaxation time of methylene resonance compared to other lipid resonances. Methods: The examinations were performed using a 3.0 T scanner with a point — resolved spectroscopy (PRESS) sequence. Lipid relaxation time in a lipid phantom filled with canola oil was estimated considering repetition time (TR) as 6000 msec and echo time (TE) as 40 — 550 msec. For in vivo proton magnetic resonance spectroscopy ({sup 1}H — MRS), eight male Sprague — Dawley rats were given free access to a normal - chow (NC) and eight other male Sprague-Dawley rats were given free access to a high — fat (HF) diet. Both groups drank water ad libitum. T{sub 2} measurements in the rats’ livers were conducted at a fixed TR of 6000 msec and TE of 40 – 220 msec. Exponential curve fitting quality was calculated through the coefficients of determination (R{sup 2}). Results: A chemical analysis of phantom and liver was not performed but a T{sub 2} decay curve was acquired. The T{sub 2} relaxation time of methylene resonance was estimated as follows: NC rats, 37.07 ± 4.32 msec; HF rats, 31.43 ± 1.81 msec (p < 0.05). The extrapolated M0 values were higher in HF rats than in NC rats (p < 0.005). Conclusion: This study of {sup 1}H-MRS led to sufficient spectral resolution and signal — to — noise ratio differences to characterize all observable resonances for yielding T{sub 2} relaxation times of methylene resonance. {sup 1}H — MRS relaxation times may be useful for quantitative characterization of various liver diseases, including fatty liver disease. This study was supported by grant (2012-007883 and 2014R1A2A1A10050270) from the Mid-career Researcher Program through the NRF funded by Ministry of Science. In addition, this study was supported by the Industrial R&D of MOTIE/KEIT (10048997, Development of the core technology for integrated therapy devices based on real-time MRI-guided tumor tracking)

  13. Localization of Small Peripheral Pulmonary Lesion by Methylene Blue Injection With Radial Endobronchial Ultrasonography in Sublobar Resection.

    PubMed

    Liu, Zhengcheng; Yang, Rusong; Shao, Feng; Pan, Yanqing

    2016-02-01

    Ultrasonography can be performed as an adjunct to aid in the localization of small nodules. We describe 25 patients with computed tomographic evidence of peripheral pulmonary lesions (PPLs) who underwent bronchoscopy with endobronchial ultrasonography (EBUS) for localization. The results demonstrate that methylene blue injection with radial EBUS is a simple and easy location technique for PLLs in Sublobar resection.

  14. A universally applicable and rapid method for measuring the growth of streptomyces and other filamentous microorganisms by methylene blue adsorption-desorption.

    PubMed

    Fischer, Marco; Sawers, R Gary

    2013-07-01

    Quantitative assessment of growth of filamentous microorganisms, such as streptomycetes, is generally restricted to determination of dry weight. Here, we describe a straightforward methylene blue-based sorption assay to monitor microbial growth quantitatively, simply, and rapidly. The assay is equally applicable to unicellular and filamentous bacterial and eukaryotic microorganisms.

  15. 7-Nitroindazole and methylene blue, inhibitors of neuronal nitric oxide synthase and NO-stimulated guanylate cyclase, block MK-801-elicited behaviors in mice.

    PubMed

    Deutsch, S I; Rosse, R B; Paul, S M; Tomasino, V; Koetzner, L; Morn, C B; Mastropaolo, J

    1996-07-01

    We examined the abilities of 7-nitroindazole and methylene blue, inhibitors of the neuronal isoform of nitric oxide synthase (NOS) and nitric oxide-stimulated guanylate cyclase activity respectively, to attenuate explosive episodic jumping behavior(s) ("popping") elicited by MK-801 in mice. MK-801, like phencyclidine (PCP), is a high-affinity, noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor. We have postulated that MK-801-elicited popping behavior in mice represents an animal model of schizophrenia, because popping behavior is markedly inhibited/antagonized by both typical and atypical antipsychotic drugs. In the present study, popping behavior induced by MK-801 was measured using an automated detection system that quantifies vertical displacements on the testing platform. 7-Nitroindazole (100 mg/kg) and methylene blue (32 and 100 mg/kg) significantly reduced the number and force of MK-801-elicited popping behavior. Mouse rotorod performance did not differ between animals receiving 7-nitroindazole, methylene blue, or their respective vehicles, suggesting that attenuation of MK-801-elicited popping behavior was not due to either sedation or ataxia caused by 7-nitroindazole or methylene blue. Our findings suggest that nitric oxide may, in part, mediate behaviors induced by NMDA receptor antagonists, like MK-801, and that inhibitors of NOS may have antipsychotic actions.

  16. Clickable Cγ-azido(methylene/butylene) peptide nucleic acids and their clicked fluorescent derivatives: synthesis, DNA hybridization properties, and cell penetration studies.

    PubMed

    Jain, Deepak R; Ganesh, Krishna N

    2014-07-18

    Synthesis, characterization, and DNA complementation studies of clickable C(γ)-substituted methylene (azm)/butylene (azb) azido PNAs show that these analogues enhance the stability of the derived PNA:DNA duplexes. The fluorescent PNA oligomers synthesized by their click reaction with propyne carboxyfluorescein are seen to accumulate around the nuclear membrane in 3T3 cells.

  17. Photocatalytic degradation of methylene blue and inactivation of gram-negative bacteria by TiO2 nanoparticles in aqueous suspension

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The photocatalytic degradation of methylene blue (MB) and inactivation of Gram-negative bacteria E. coli K12 and P. aeruginosa by TiO2 nanoparticles in aqueous suspension were studied. TiO2 resulted in significant reduction in MB absorption and a shift of MB absorption peak from 664 nm to 658 nm aft...

  18. Comment on "Conformational analysis of small organic molecules using NOE and RDC data: A discussion of strychnine and α-methylene-γ-butyrolactone"

    NASA Astrophysics Data System (ADS)

    Khodov, I. A.; Kiselev, M. G.; Efimov, S. V.; Klochkov, V. V.

    2016-05-01

    In a recent paper published in this journal, Kolmer et al. [1] reported an experimental approach for conformational analysis of small organic molecules using NOE and RDC techniques. The authors obtained information on conformation of strychnine and α-methylene-γ-butyrolactone molecules. In addition, possible sources of error in the measurement and analysis process and ideas of how to exclude them were discussed.

  19. One-pot preparation of trifluoromethylated homoallylic N-acylhydrazines or α-methylene-γ-lactams from acylhydrazines, trifluoroacetaldehyde methyl hemiacetal, allyl bromide and tin.

    PubMed

    Du, Ganggang; Huang, Danfeng; Wang, Ke-Hu; Chen, Xiaowei; Xu, Yanli; Ma, Junyan; Su, Yingpeng; Fu, Ying; Hu, Yulai

    2016-01-28

    An efficient and convenient one-pot method for the preparation of trifluoromethylated homoallylic N-acylhydrazines or α-methylene-γ-lactams has been described. In this process, allyl bromide and metal tin are used instead of toxic stannanes, and commercially available aqueous trifluoroacetaldehyde methyl hemiacetal was used as a trifluoromethyl source.

  20. Structural flexibility of 4,4'-methylene diphenyl diisocyanate (4,4'-MDI): evidence from first principles calculations.

    PubMed

    Rodziewicz, Pawel; Goclon, Jakub

    2014-02-01

    A reactant used globally in the production of polyurethane is the molecule 4,4'-methylene diphenyl diisocyanate (4,4'-MDI). The structural flexibility of 4,4'-MDI is one of the most important molecular properties influencing the polymerization process and this property was therefore modeled using density functional theory (DFT) calculations and Car-Parrinello molecular dynamics (MD) simulations. Global and local minima structures were found and confirmed by vibrational analysis. The energy barriers related to rotation of the aromatic rings were estimated by DFT calculations. The stability of global and local minima was verified by Car-Parrinello (MD) runs at finite temperature. The presence of weak C-H⋯π hydrogen bonds was confirmed by atoms in molecules analysis and found to be responsible for the low energy barriers.