Cleavage Of Azo Bond Research Articles

Decolourization of azo dyes using magnesium–palladium system

Magnesium–palladium system was found to efficiently decolourize reactive black 5, sunset yellow FCF and tartrazine dyes. There is complete loss of visible range absorption peaks and extent of colour removal exceeded 95% within 24 h of reaction. There is appearance of new peak(s) in the UV region and/or gradual and significant shift of the λ max in the UV range during 1–24 h of reaction of dyes with Mg/Pd system. LC–MS analyses following the reaction of dyes with magnesium palladium system suggest reductive cleavage of azo bonds and formation of amines as the end products. Kinetic analyses of dye decolourization indicate that the reaction follows first order kinetics. Agreement between the experimental and predicted Michaelis–Menten plots for the decolourization of reactive black 5, sunset yellow FCF and tartrazine dyes by Mg 0/Pd 4+ system, suggests the correctness of Michaelis–Menten model for the prediction of dye decolourization rates by Mg 0/Pd 4+ system. Our investigations reveal that Mg 0/K 2PdCl 6 system is more effective in decolourizing dyes as compared to Mg 0/Pd 0–alumina or Mg 0 alone. Results obtained from reuse experiments suggest that Pd 0 pellets have the potential for recycling which will make the treatment process cost effective. Mg 0/Pd 4+ system was found to be efficient in decolourizing mixture of drimarene, remazol and procion dyes as well as raw effluent generated by textile dye manufacturing company.

Thermal and Electrical Properties of “Liquid” Nano Carbon and its Applications in Fuel Cell Technology

In the previous study, we conducted the study of chemical top down process which seems to provide better efficiency and better cost saving than the physical top down in the fabrication of nano scale, especially, when applying to carbon materials. It is found that the chemical top down performs effectively with multiple attachments of electrolytic groups onto the surface of the carbon powder by diazo coupling reaction. As a result, we are able to isolate the nano scale of carbon particles with strong polar solvents such as water and believe that it is due to electrostatic repulsive force between same sign charges existing in the polarized electrolytic groups… In the present study, we found that the cleavage of azo bond in the coupling product can occur above 110°C in ambient condition but it can also escape the thermal decomposition by a nano composite structure using specific emulsion polymer as binder matrix. Electrolytic groups which carry charge from ionization are speculated to reduce electron transport but enhance proton transport capability of carbon material, have successfully demonstrated a proton exchange membrane (PEM) which exhibits better heat resistance and higher current density than the commercial PEM Nafion product in the PEM fuel cell application. The multiple coupling product exhibits a core-shell structure composed of a nano scale hydrophobic core and electrolytic shell, showing apparent “solubility “and named as “liquid” nano carbon (LNC).

Colon-specific 9-aminocamptothecin-HPMA copolymer conjugates containing a 1,6-elimination spacer

N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymer–9-aminocamptothecin (9-AC) conjugate for oral colon-specific drug delivery was designed, synthesized, and characterized. The drug, 9-AC, was attached to the polymer carrier via a spacer containing a combination of an aromatic azo bond and a 4-aminobenzylcarbamate group. The design of the spacer ensured a fast and highly efficient release of unmodified 9-AC from the polymer in the colon by azo bond cleavage followed by a 1,6-elimination mechanism. An in vitro degradation study indicated that this conjugate was stable in simulated upper GI tract conditions, including small intestine (SI) contents, SI mucosa suspension, and in PBS (pH 1.5 and 7.4). A fast release of the unmodified drug (85±10% of 9-AC in 12 h) was detected in rat cecal contents. This drug delivery system has potential in the treatment of colon cancer.

Effects of surface modification of TiO 2 with ascorbic acid on photocatalytic decolorization of an azo dye reactions and mechanisms

The formation of surface modification on TiO 2, which can be easily attained by a simple addition of ascorbic acid to aqueous TiO 2 suspensions, uniquely affects both photocatalytic reactions and mechanisms. Surface modification results in the formation of a colored surface complex that causes red shift of the absorption threshold of TiO 2, enhancing utilization of the solar spectrum. The decolorization rate of methyl orange, taken as a model for recalcitrant azo-dye, was observed to be the function of surface modified TiO 2 used during the process. It was found that surface modified TiO 2 was more effective for oxidation of azo bond than pure TiO 2 irradiated by both UV light and solar light. Through investigating the effects of dissolved oxygen, CCl 4 and tert-butyl alcohol on the decolorization of methyl orange, the mechanisms are proposed that the superoxides ( O 2 −) mediated oxidation pathways are dominant for cleavage of azo bond of methyl orange on surface modified TiO 2 with ascorbic acid, whereas the OH radical mediated oxidation pathways are largely inhibited due to the hindered complexation of ascorbic acid on the surface of TiO 2. Finally, elementary charge transfer process on surface modified TiO 2 and the implication to photocatalytic reaction pathway are discussed.

Decolorization kinetics of the azo dye Reactive Red 2 under methanogenic conditions: effect of long-term culture acclimation

The biological decolorization of the textile azo dye Reactive Red 2 was investigated using a mixed, mesophilic methanogenic culture, which was developed with mixed liquor obtained from a mesophilic, municipal anaerobic digester and enriched by feeding a mixture of dextrin/peptone as well as media containing salts, trace metals and vitamins. Batch decolorization assays were conducted with the unacclimated methanogenic culture and dye decolorization kinetics were determined as a function of initial dye, biomass, and carbon source concentrations. Dye decolorization was inhibited at initial dye concentrations higher than 100 mg l(-1) and decolorization kinetics were described based on the Haldane model. The effect of long-term culture exposure to the reactive dye on decolorization kinetics, culture acclimation, as well as possible dye mineralization was tested using two reactors fed weekly for two years with an initial dye concentration of 300 mg l(-1) and a mixture of dextrin/peptone. The maximum dye decolorization rate after a 2-year acclimation at an initial dye concentration of 300 mg l(-1) was more than 10-fold higher as compared to that obtained with the unacclimated culture. Aniline and the o-aminohydroxynaphthalene derivative resulting from the reductive azo bond cleavage of the dye were detected, but further transformation(s) leading to dye mineralization were not observed. Reactive Red 2 did not serve as the carbon and energy source for the mixed culture, and dye decolorization was sustained by the continuous addition of dextrin and peptone. Thus, biological decolorization of reactive azo dyes is feasible under conditions of low redox potential created and maintained in overall methanogenic systems, but supply of a biodegradable carbon source is necessary.

Evaluation of an integrated anaerobic/aerobic SBR system for the treatment of wool dyeing effluents

This work examined the performance of a sequencing batch reactor treating dyeing effluents from a factory that processes mainly wool and wool/polyester blends. Different operational conditions were evaluated, namely the influence of the anaerobic and the subsequent aerobic phase on the organic load removal, as well as the effect of the length of the aeration period (from 8 to 12 h) on process efficiency. A comparison between a fill stage in fast and slow modes was carried out. Results indicate that the cycle 2 conditions (fast fill and 12 h aeration time) improved the overall efficiency (85+/-6% soluble COD and 95+/-4% BOD5 removal yields) with a predominant COD uptake occurring in the aerobic stage. Slow, linear COD removal was observed in the anaerobic phase, in contrast with an exponential COD decrease in the oxic phase. For SS a level under 100 mg/l was general achieved in the exit of the reactor. With respect to dye degradation, a noticeable decrease of the absorbance measured in the UV-visible range was observed. This could be explained by the reduction of the azo bonds of some of the present dyes in the anaerobic step, in which ORP values lower than -400 mV were attained. Some oxidation of anthraquinone sulphonate dyes and of the aromatic amines resulting from azo bond cleavage could also have been taken place, as well as bioelimination mechanisms such as dye sorption.

Monoazo and diazo dye decolourisation studies in a methanogenic UASB reactor

Mixed anaerobic bacterial consortia have been show to reduce azo dyes and batch decolourisation tests have also demonstrated that predominantly methanogenic cultures also perform azo bond cleavage. The anaerobic treatment of wool dyeing effluents, which contain acetic acid, could thus be improved with a better knowledge of methanogenic dye degradation. Therefore, the decolourisation of two azo textile dyes, a monoazo dye (Acid Orange 7, AO7) and a diazo dye (Direct Red 254, DR254), was investigated in a methanogenic laboratory-scale Upflow Anaerobic Sludge Blanket (UASB), fed with acetate as primary carbon source. As dye concentration was increased a decrease in total COD removal was observed, but the acetate load removal (90%) remained almost constant. A colour removal level higher than 88% was achieved for both dyes at a HRT of 24 h. The identification by HPLC analysis of sulfanilic acid, a dye reduction metabolite, in the treated effluent, confirmed that the decolourisation process was due mainly to azo bond reduction. Although, HPLC chromatograms showed that 1-amino-2-naphthol, the other AO7 cleavage metabolite, was removed, aeration batch assays demonstrated that this could be due to auto-oxidation and not biological mineralization. At a HRT of 8 h, a more extensive reductive biotransformation was observed for DR254 (82%) than for AO7 (56%). In order to explain this behaviour, the influence of the dye aggregation process and chemical structure of the dye molecules are discussed in the present work.

Anaerobic/aerobic sequential treatment of a cotton textile mill wastewater

AbstractThe treatment of a wastewater taken from a cotton textile mill was investigated using an anaerobic/aerobic sequential system during an operational period of 87 days. The process units consisted of an upflow anaerobic sludge blanket (UASB) reactor and a continuous stirred tank reactor (CSTR). Wastewater characterization was performed before feeding the reactor system. Glucose‐COD, and azo dyes were added to the textile wastewater for comparative purposes in the final period of operation. The pH values in the effluent of the UASB reactor were suitable for optimal anaerobic treatment in all runs. The biodegradable part of the COD in wastewater was removed effectively, with the anaerobic stage improving the biodegradability of wastewater entering the aerobic stage. The UASB reactor permitted COD and color removals of 9–51% and 46–55%, respectively, at a hydraulic retention time (HRT) of 30 h. COD removal efficiencies were between 40 and 85% and color removal efficiencies were 39–81% in normal and artificially‐colored wastewaters at a total HRT of 5.75 days in the UASB/CSTR reactor system. Benzidine produced from the cleavage of azo bond in the anaerobic stage was effectively removed in the aerobic stage, and was identified by comparison of its HPLC spectrum with that of an authentic specimen. Copyright © 2004 Society of Chemical Industry

Effects of alkalinity and co-substrate on the performance of an upflow anaerobic sludge blanket (UASB) reactor through decolorization of Congo Red azo dye

The effect of substrate (glucose) concentrations and alkalinitiy (NaHCO 3) on the decolorization of a synthetic wastewater containing Congo Red (CR) azo dye was performed in an upflow anaerobic sludge blanket (UASB). Color removal efficiencies approaching 100% were obtained at glucose-COD concentrations varying between 0 and 3000 mg/l. The methane production rate and total aromatic amine (TAA) removal efficiencies were found to be 120 ml per day and 43%, respectively, while the color was completely removed during glucose-COD free operation of the UASB reactor. The complete decolorization of CR dye under co-substrate free operation could be attributed to TAA metabolism which may provide the electrons required for the cleavage of azo bond in CR dye exist in the UASB reactor. No significant differences in pH levels (6.6–7.4), methane production rates (2000–2700 ml/day) and COD removal efficiencies (82–90%) were obtained for NAHCO 3 concentrations ranging between 550 and 3000 mg/l. However, decolorization efficiency remained at 100% with decreasing NaHCO 3 concentrations as low as 250 mg/l in the feed. An alkalinity/COD ratio of 0.163 in the feed was suggested for simultaneous optimum COD and color removal.

Photochromic polyacylsemicarbazides based on azobenzene containing dihydrazide

AbstractPolyacylsemicarbazides exhibiting photochromic behaviour were synthesised by solution polymerisation of azobenzene chromophore containing dihydrazide and various diisocyanates (aliphatic, cycloaliphatic and aromatic). A model compound was also prepared from o‐tolylene isocyanate and dihydrazide. The structures were confirmed by 1H NMR and FTIR techniques. The polymers were found to exhibit λmax values around 330 nm corresponding to the trans isomer which reduced with irradiation of the solutions of polymers in DMAc due to trans→cis isomerisation as observed by UV‐VIS spectrometry. The reverse reaction (cis→trans isomerisation) was found to take place photochemically when irradiated with visible light or when kept in the dark. The rates of isomerisation reactions were found to be independent of the chromophore concentration and the nature of the polymer backbone. The inherent viscosity of the solutions of polymers in DMAc reduced upon irradiation with UV light and was regained in the dark. Thermal studies showed that the polymer degradation started with the simultaneous cleavage of imino (NN) and aromatic azo (NN) bond and that recrystallisation occurred on heating the samples. Copyright © 2004 Society of Chemical Industry

The mechanism and kinetics of the electrochemical cleavage of azo bond of 2-hydroxy-5-sulfophenyl-azo-benzoic acids

The electrochemical reduction of 2-hydroxy-5-[(4-sulfophenyl)azo]benzoic acid, 2-hydroxy-5-[(3-sulfophenyl)azo]benzoic acid, 2-hydroxy-5-[(2-sulfophenyl)azo]benzoic acid and 2-hydroxy-5-azo-benzoic acid has been carried out in aqueous solutions at glassy carbon electrode using cyclic voltammetry and chronoamperometry. The position of sulfo substituent relative to azo bridge as well as pH of the solution have significant impact on the electrochemical behavior of these compounds. It has been proposed that these compounds are reduced predominantly as hydrazone tautomers resulting in corresponding hydrazo compounds. The overall electrochemical reduction follows DISP2 mechanism, ultimately leading to the 5-amino salicylic acid and sulfanilic acid. The rate determining step is the homogenous redox reaction between intermediate hydrazo compound and 5-amino salicylic acid quinoneimine. The mechanism is proposed in which activated complex of 5-amino salicylic acid quinoneimine and intermediate hydrazo compound is formed with the simultaneous loss of one proton.

Adsorptive Immobilization of a Pseudomonas Strain on Solid Carriers for Augmented Decolourization in a Chemostat Bioreactor

Pseudomonas GM3, a highly efficient strain in cleavage of azo bonds of synthetic dyes under anoxic conditions, was immobilized via adsorption on two types of carriers, porous glass beads and solid PVA particles. The cells were cultivated in a nutrient medium, adsorbed on sterile carriers, stabilized as biofilms in repeated batch cultures, and introduced into a chemostat activated sludge reactor for augmented decolourization. The microbial cells were quickly adsorbed and fixed on the PVA surface, compared to a slow and linear immobilization on the glass surface. The porous structure of glass beads provided shelter for the embedded cells, giving a high biomass loading or thick biofilm (13.3 mg VS ml−1 carrier) in comparison with PVA particles (4.8 mg VS ml−1 carrier), but the mass transfer of substrate in the biofilm became a significant limiting factor in the thicker biofilms (effectiveness factor η = 0.31). The microbial decolourization rate per volume of carriers was 0.15 and 0.17 mg dye ml−1 of glass beads and PVA particles, respectively. In augmented decomposition of a recalcitrant azo dye (60 mg l−1), the immobilized Pseudomonas cells in porous glass beads gave a stable decolourization efficiency (80 - 81%), but cells fixed on solid PVA particles showed an initial high colour removal of 90% which then declined to a stable removal efficiency of 81%. In both cases, the colour removal efficiency of the chemostat bioreactor was increased from < 10% by an activated sludge to ∼80% by the augmented system.

Anaerobic Reduction of a Sulfonated Azo Dye, Congo Red, by Sulfate-Reducing Bacteria

The capacity for anaerobic decolorization of a sulfonated azo dye, Congo Red, by a strain of a sulfate-reducing bacterium was evaluated. After optimizing the growth rate of the bacteria on a simple carbon source and terminal electron acceptor pair, lactate and sulfate, respectively, the effect of the dye concentration on their growth rate was analyzed. The decolorization rate was affected by the dye concentration in the growth medium. The azo-bond cleavage mechanism of reductive decolorization with the formation of benzidine was consistent with the results, as this metabolite was identified by high-performance liquid chromatography. Several fractions of the culture medium, including lysed cell extracts, were examined for the capacity to reduce the azo dye. This reduction capacity was found in the culture medium in which the cells had previously grown. The results showed that the mechanism of reductive decolorization of this sulfonated azo dye was extracellular and nonenzymatic, consistent with the production of sulfide anion by the microorganisms while growing on lactate and sulfate. The sulfide anions were the cause of the reduction leading to the disappearance of color in the medium. To increase the rate of decolorization, the presence of ferrous ion was also necessary together with the lactate and sulfate substrates.

Voltammetric studies of 2-hydroxy-5-[(4-sulfophenyl)azo]benzoic acid as a novel prodrug of 5-aminosalicylic acid.

The electrochemical properties of a colon-targeted prodrug of 5-aminosalicylic acid (5-ASA), 2-hydroxy-5-[(4-sulfophenyl)azo]benzoic acid (SPSA), were investigated in aqueous solutions at glassy carbon electrodes using cyclic voltammetry and controlled potential electrolysis. The influence of the pH and experimental time domain on the reaction pathway has been studied. The electrochemical reduction of SPSA is identified as an ECE process always leading to the cleavage of azo bond. In an acidic media SPSA is reduced in a 4e(-)/4H(+) process yielding 5-ASA and sulfanilic acid. In neutral and weakly basic media SPSA is reduced in 2e(-)/2H(+) process resulting in the hydrazo intermediate that is stable enough to enable its reoxidation back to SPSA in the time scale of the cyclic voltammetry.

Novel azo derivatives as prodrugs of 5-aminosalicylic acid and amino derivatives with potent platelet activating factor antagonist activity.

This paper describes the synthesis of a series of azo compounds able to deliver 5-aminosalicylic acid (5-ASA) and a potent platelet activating factor (PAF) antagonist in a colon-specific manner for the purpose of treating ulcerative colitis. We found it possible to add an amino group on the aromatic moiety of our reported 1-[(1-acyl-4-piperidyl)methyl]-1H-2-methylimidazo[4,5-c]pyridine derivatives or on British Biotech compounds BB-882 and BB-823 maintaining a high level of activity as PAF antagonist. A selected compound UR-12715 (49c) showed an IC(50) of 8 nM in the in vitro PAF-induced aggregation assay, and an ID(50) of 29 microg/kg in the in vivo PAF-induced hypotension test in normotensive rats. Through attachment of 49c to the 5-ASA via azo functionality we obtained UR-12746 (70). Pharmacokinetics experiments with [14C]-70 allow us to reach the following conclusions, critical in the design of these new prodrugs of 5-ASA. Neither the whole molecule 70 nor the carrier 49c were absorbed after oral administration of [14C]-70 in rat as was demonstrated by the absence of plasma levels of radioactivity and the high recovery of it in feces. Effective cleavage of azo bond (84%) by microflora in the colon is achieved. These facts ensure high topical concentrations of 5-ASA and 49c in the colon. Additionally, 70 exhibited a potent anticolitic effect in the trinitrobenzenesulfonic acid-induced colitis model in the rat. This profile suggests that UR-12746 (70) provides an attractive new approach to the treatment of ulcerative colitis.

Biological Decolorization of the Azo Dye Reactive Red 2 Under Various Oxidation–Reduction Conditions

The decolorization of the azo dye reactive red 2 (RR2) was investigated under aerobic, anoxic, and methanogenic conditions. The dye was not decolorized by an aerobic culture kept under aerobic conditions for 7 days. However, incubation of the same culture under anoxic conditions resulted in RR2 decolorization with an initial rate of 40 mg/L·d and to an extent of 91.7% after the culture oxidation–reduction potential (ORP) dropped to less than ‐50 mV. A second addition of RR2 to the same culture kept under anoxic conditions resulted in a greater initial RR2 decolorization rate (86 mg/L·d) at an ORP value of –250 mV. Decolorization of RR2 at an initial dye concentration of 300 mg/L was achieved by an unacclimated methanogenic culture at an initial rate of 83 mg/L·d and without any inhibition. However, as a result of acclimation, initial RR2 decolorization rates of 523 and 1050 mg/L·d were achieved by the same methanogenic culture after 5 months and 2 years of weekly additions of 300 mg/L RR2, respectively. Dye decolorization followed Michaelis–Menten kinetics. Under methanogenic conditions and at an initial dye concentration of 300 mg/L, the maximum RR2 decolorization rate per unit biomass was 0.12 and 0.70 mg RR2/mg volatile suspended solids d without acclimation and after a 2‐year acclimation, respectively. Lack of significant RR2 decolorization was observed in autoclaved methanogenic culture controls. Therefore, the reductive cleavage of the dye azo bond resulting in the decolorization of RR2 and formation of aromatic amines was biologically mediated and is attributed to the reduced conditions created and maintained by the anoxic and anaerobic cultures. Thus, biological decolorization of reactive azo dyes is feasible under anoxic–anaerobic conditions and should be further explored for textile wastewater management.

Understanding anaerobic decolourisation of textile dye wastewater: mechanism and kinetics

Worldwide, some 280,000 tons of textile dyes are discharged per annum. Degradation of the predominant highly soluble reactive dyes is poor within activated sludge plants, and instead requires anaerobic pretreatment for reductive cleavage of the chromogenic azo bond to precede aerobic degradation. The mechanism for the anaerobic reductive cleavage, which results in decolourisation, is not well understood. Further, thermophilic anaerobic pre-treatment has not been reported, although the wastewater is produced at high temperature (50–80°C). This project therefore aimed to compare decolourisation kinetics under mesophilic (35°C) and thermophilic (55°C) conditions and elucidate biotic and abiotic factors in the decolourisation of the dye, Reactive Red 235. Preliminary experiments indicated that acclimation of the up-flow anaerobic sludge blanket (UASB) biomass was unnecessary and there was no dye toxicity at expected wastewater concentrations (0.05–0.1g/L). Decolourisation of Reactive Red 235 was studied under batch conditions with intact and autoclaved biomass, and also using the pre-reduced supernatant from a spent culture (0.2 μm filtered). Based on HPLC identification of the dye and reaction products, first-order kinetics was observed and rate constants of –0.0096/min (thermophilic) and –0.0034/min (mesophilic) were estimated for intact, viable biomass. Abiotic decolourisation was 60–80% lower for the autoclaved samples, and under 12–35% lower for the filtered supernatant. Hence it may be concluded that active anaerobic cells give the most efficient and complete decolourisation, especially under thermophilic conditions. Nonetheless, abiotic reduction does occur and has implications for the design of a novel uncoupled reactor system.

Isolation and Characterization of Aeromonas sp. B-5 Capable of Decolorizing Various Dyes.

Aeromonas sp. B-5, which has the ability to decolorize azo dyes, was isolated from soil. Aeromonas sp. B-5 completely decolorized 100 mg/ l of Bordeaux S by reductive cleavage of azo bonds under static conditions in 24 h. Though the decolorization of Bordeaux S by Aeromonas sp. B-5 was suppressed under shaking, rapid decolorization was observed when the culture was changed to static conditions after cultivation with shaking. The indigoid dye, Acid blue 74, was decolorized by Aeromonas sp. B-5 under shaking conditions, in contrast to the decolorization of azo dyes.

Isolation and characterization of Aeromonas sp. B-5 capable of decolorizing various dyes

Aeromonas sp. B-5, which has the ability to decolorize azo dyes, was isolated from soil. Aeromonas sp. B-5 completely decolorized 100 mg/ l of Bordeaux S by reductive cleavage of azo bonds under static conditions in 24 h. Though the decolorization of Bordeaux S by Aeromonas sp. B-5 was suppressed under shaking, rapid decolorization was observed when the culture was changed to static conditions after cultivation with shaking. The indigoid dye, Acid blue 74, was decolorized by Aeromonas sp. B-5 under shaking conditions, in contrast to the decolorization of azo dyes.

Regeneration of Dye-Saturated Quaternized Cellulose by Bisulfite-Mediated Borohydride Reduction of Dye Azo Groups: An Improved Process for Decolorization of Textile Wastewaters

Cellulosics modified to contain quaternary ammonium groups have a strong affinity for anionic dyes. Therefore, ion exchangers based on quaternized cellulose or lignocellulose can be used to remove textile dyes from wastewater. However, restoration of exchanger binding capacity is poor using conventional, low-cost regenerants. Experiments were conducted with two monoazo dyes, Orange II (Acid Orange 7) and Remazol Red F3B (Reactive Red 180), to determine whether reductive cleavage of dye azo bonds improves exchanger regenerability. Treatment with the redox couple KBH4/NaHSO3 fully restored the binding capacity of Orange II-saturated quaternized cellulose. KBH4/NaHSO3 treatment of quaternized cellulose saturated with Remazol Red F3B (hydrolyzed, unreactive form) restored 74% of the exchanger binding capacity, which increased to 95% with a subsequent wash with NaOH or NaClO4. High-performance liquid chromatography was used to confirm that KBH4/NaHSO3 reductively cleaved dye azo bonds. Bisulfite was found to f...