Various Concentrations Of Formaldehyde Research Articles

Effect of chain topology on plasmonic properties of pressure sensor films based on poly(acrylamide) and Au nanoparticles

Au nanoparticles have been recognized as a colorimetric sensing element in polymeric systems because clustering shifts the red color of individual particles into saturated blue due to distinct plasmonic variation. The mechanism of pressure sensing is based on the disintegration of the particle clusters into the individual particles in polymers upon application of pressure. Polymers are usually composed of linear chains that provide a viscoelastic medium for their diffusion. Changing topology of polymer chains from linear to crosslinked under fixed pressure makes a clear change in spectral features of the particles probably due to the hindrance of particle diffusion by the crosslinking points. Therefore, the working range of the sensor films can be increased to higher-pressure values. In this work, polyacrylamide/Au nanoparticle films were prepared by various concentrations of formaldehyde as a crosslinking agent from 0.5 to 5.0 wt %. The initial absorption signal gradually shifts from 690 to 545 nm for linear chains upon application of pressure while shifting goes down to 571 nm for crosslinked ones. The colorimetric change is also examined under humid environments. Contrary to the crosslinking process, humid environment facilitates the diffusion of particles since the chains swell with water molecules that provide a convenient medium for particle diffusion.

Attenuation of Eimeria tenella with immersion Various concentration of Formaldehyde in inducing Protective immunity after challenge Test by Featuring Macroscopic and Microscopic caecum

Background: Eimeria tenella parasite is one of the most pathogenic coccidia that can infect chickens. The strategy for prevention and control of coccidiosis is done by administering anticoxidia drugs and live oocyst vaccines. However, anticoxidia can cause resistance to coccidiosis. So it is necessary to make vaccines ( attenuation) using formalin or formaldehyde. Aim: The purpose of this study was to determine whether the attenuation of the pathogenicity E. tenella with immersion various concentrations of formaldehyde can induce protective immunity and the concentration of formaldehyde that is most effective in inducing protective immunity for attenuation of E. tenella in featuring cecal macroscopic and microscopic (lesion score). Method: Twenty-five chickens at three weeks old were divided randomly into five groups. Challenge test did after the first infection. The first infection was inoculated tenella by divided the first group (P0) is chicken group was inoculated with 0% formaldehyde soaked E. tenella at 1 x 104 doses as control, the 2nd, 3rd and 4th groups (P1; P2, P3 and P4) were inoculated 0.15%, 0.3%, 0.6% and 1.2% of formaldehyde soaked E. tenella at the same doses, respectively. On challenge test performed two weeks after the first infection by inoculated 15x103 infective oocysts of E. tenella. Result: The results showed that the attenuation of E. tenella with immersion various concentrations of formaldehyde can induce protective immunity by featuring cecal macroscopic and microscopic (lesion score). Conclusion: The most effective concentration of formaldehyde in inducing protective immunity of the attenuation pathogenicity E. tenella was 1.2%. Keywords: attenuation, E. tenella, formaldehyde, protective immunity

Isolation and Characteristics of a Formaldehyde-Degrading Fungus

Nine novel formaldehyde-resistant fungi were isolated from 170 soils and wastewater samples from Aichi prefecture. When these fungi were cultured in medium containing various concentrations of formaldehyde after being cultured in a plate of basal medium containing 1.5% agar and 0.2% formaldehyde, 0.30–0.50% formaldehyde was almost completely consumed in the medium containing glucose as the carbon source. The highest degradation activity of the 9 strains was obtained for, strain IRI017; the fungi could grow in medium containing 0.5% formaldehyde and almost all of the formaldehyde was degraded in 100 h. This was the highest formaldehyde concentration for biological direct degradation as far as we know. Strain IRI017 was identified as Paecilomyces variotii from sequence analysis of 18S rDNA. When cell-free extracts of strain IRI017 were prepared from cell suspension using medium supplemented with formaldehyde and glucose as the carbon source, high nicotinamide adenine dinucleotide (NAD)-linked, glutathione (GSH)-dependent formaldehyde dehydrogenase activity 1.68 µmol/(min·mg-protein) was detected. When strain IRI017 was suspended in buffer solution at an initial formaldehyde concentration of 0.26%, the cells degraded the formaldehyde completely in 150 h.

Screening process for activity determination of conductive oxide electrodes for organic oxidation

A modified method for the calculation of the normalized faradaic charge (q fN) is proposed. The method involves the simulation of an oxidation process, by cyclic voltammetry, by employing potentials in the oxygen evolution reaction region. The method is applicable to organic species whose oxidation is not manifested by a defined oxidation peak at conductive oxide electrodes. The variation of q fN for electrodes of nominal composition Ti/RuX Sn1-X O2 (x = 0.3, 0.2 and 0.1), Ti/Ir0.3Ti0.7O2 and Ti/Ru0.3Ti0.7O2 in the presence of various concentrations of formaldehyde was analyzed. It was observed that electrodes containing SnO2 are the most active for formaldehyde oxidation. Subsequently, in order to test the validity of the proposed model, galvanostatic electrolyses (40 mA cm-2) of two different formaldehyde concentrations (0.10 and 0.01 mol dm-3) were performed. The results are in agreement with the proposed model and indicate that this new method can be used to determine the relative activity of conductive oxide electrodes. In agreement with previous studies, it can be concluded that not only the nature of the electrode material, but also the organic species in solution and its concentration are important factors to be considered in the oxidation of organic compounds.

Effects of formaldehyde exposure on granule cell number and volume of dentate gyrus: A histopathological and stereological study

The hippocampal formation is a complex region of the brain related to memory and learning. The purpose of the present study was to determine whether exposure of neonatal rats to formaldehyde (FA) had either early or delayed effects on the numbers of granule cells in the dentate gyrus (DG). After birth, the neonatal male Wistar rats were exposed throughout a 30-day period to various concentrations of FA: 0 (control group), 6 ppm (low concentration group) and 12 ppm (high concentration group). This was done by placing them for 6 h/day and 5 days per week in a glass chamber containing FA vapor. Then, five animals from each group were anesthetized and decapitated on postnatal day (PND) 30, and the remaining five animals were sacrificed on PND 90 by intracardiac perfusion using 10% neutral buffered FA solution. The Cavalieri principle of stereological approaches was used to determine the volume of the DG in these sections. The optical fractionator counting method was used to estimate the total number of granule cells in the DG. The appearance of granule cells was normal under light microscopy in all PND 30 and PND 90 groups. There were significant age-related reductions in the volume of the DG at PND 90 irrespective of which group was examined. Significant age-related neuron loss was also determined at PND 90 compared to that at PND 30. Rats treated with a high concentration FA were found to have fewer granule cells than either the animals treated with a low concentration FA or the control group ( p < 0.01 and p < 0.01, respectively) at PND 90 but not at PND 30. These findings clearly indicate that granule cells in the DG may be vulnerable to stress and the concentration of FA to which they are exposed during early postnatal life, and also that a neurotoxic effect of high dose FA on cell number is only seen after a long time period. These results may explain why some disorders do not appear until later life.

Anodic Oxidation Behaviors of Formaldehyde at Boron‐Doped Diamond Electrodes

AbstractThe electrochemical behaviors of formaldehyde (FA) at boron‐doped diamond (BDD) electrodes are investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear scanning voltammetry (LSV) techniques. The CV results show that the oxidation reaction of FA is influenced by the hydroxyl concentration in the solution, and the peak current response with the FA concentration is linear at the range from 10 to 100 mM. The differential capacitance from EIS results indicate that the FA molecules adsorb at the BDD electrode surface at low potential (from 1.0 to 1.4 V). The kinetic studies have been examined with the various concentrations of FA, pH, and temperature. The activation energy of FA oxidation is also calculated. The results of kinetic study indicate that the adsorption of FA molecules at the BDD electrode is the rate‐determining step at low potential (from 1.0 to 1.40 V).

Effect of formaldehyde on the expression of adhesion molecules in nasal microvascular endothelial cells: the role of formaldehyde in the pathogenesis of sick building syndrome.

Formaldehyde is associated with sick building syndrome (SBS), a set of diffuse and irritative symptoms predominantly involving the eyes and the respiratory tract. However, its pathophysiological mechanism in SBS has not yet been clarified. In this study we investigated the effect of formaldehyde on the expression of adhesion molecules on human mucosal microvascular endothelial cells (HMMECs). Furthermore, we investigated the effect of formaldehyde on adhesiveness of HMMECs to eosinophils. HMMECs were incubated with various concentrations of formaldehyde (1 ng/mL-1 microg/mL) for 24 h, and the expressions of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM-1) on HMMECs were evaluated by flow cytometry. The change in the expression of ICAM-1 and VCAM-1 mRNA was then evaluated by reverse transcriptase polymerase chain reaction. To understand the role of formaldehyde in eosinophilic inflammation of the nasal mucosa, we examined the effects of formaldehyde on the adhesiveness between HMMECs and eosinophils by eosinophil adhesion assay. Formaldehyde increased the surface expressions of ICAM-1 and VCAM-1 on HMMECs. Formaldehyde also induced ICAM-1 and VCAM-1 mRNA. In addition, the adhesiveness between HMMECs and eosinophils was also increased by formaldehyde. These in vitro studies suggest that formaldehyde may play a role as the irritant of the nasal mucosa by increasing the expressions of adhesion molecules on HMMECs and by enhancing the adhesiveness between HMMECs and eosinophils.

Stability of benzodiazepines in formaldehyde solutions.

Benzodiazepine-type drugs are used in the treatment of a number of pathologic disorders, but they may be implicated in forensic toxicology cases because of their abuse potential. Occasionally, it becomes necessary to measure drug levels following exposure to formaldehyde (postembalming or after tissue storage) if drug involvement was not previously suspected. Virtually no information exists on the decomposition of benzodiazepines in the presence of formaldehyde (the active ingredient in many embalming fluids), yet formaldehyde is known to be highly reactive, particularly with nitrogen-containing compounds. In order to evaluate the effects of formaldehyde on benzodiazepines, 10 benzodiazepine drugs were exposed to various concentrations of formaldehyde and various pH conditions (to simulate potential postembalming conditions), and the decomposition of each drug was measured by high-performance liquid chromatography over a 30-day period. The decomposition rates of all but one of the benzodiazepines were accelerated (to differing degrees) by formaldehyde as compared to controls, and this decomposition was in several cases both pH and formaldehyde concentration dependent. Thus, forensic examiners must be particularly cautious when attempting to determine benzodiazepine concentrations postembalming because the compound may have reacted with formaldehyde to form other products not inherently obvious analytically. Determination of these reaction products will serve to provide alternate analytes, allowing for establishment of accurate conclusions during forensic analyses.

Formaldehyde in cryoprotectant propanediol and effect on mouse zygotes.

Cryopreservation of human zygotes and embryos has been routinely performed by in-vitro fertilization clinics for many years. Karran and Legge (1996) first reported that formaldehyde (FA) present in the cryoprotective solutions can have a deleterious effect on mouse oocytes. FA is a cytotoxic, carcinogenic and mutagenic chemical. The effect of FA on mouse zygotes was investigated. In addition, the concentrations of FA in propanediol (PROH) obtained from various sources were determined. Pooled 1-cell embryos were dispensed into droplets of modified Ham's F10 or human tubal fluid containing various concentrations of FA. Since bovine serum albumin (BSA) may minimize toxicity additional trials were done as above in the absence of BSA. FA concentration in the standard 1.5 M PROH, from different sources in water, was measured in the same assay using a standard curve of 0-100 microM FA. FA in a complex medium had a significant deleterious effect on embryo development and hatching but only at 1 mM concentration (P < 0.000001; see Tables I-III). There was no significant effect of FA at 100 microM. However, in a simple medium even 50 microM FA decreased embryo hatching. FA was present in 1.5 M PROH from different sources (range 1.0-35.3 microM concentration). It appears that FA concentrations do not increase with storage because FA concentrations were low even after opening and storage for 3 years on the shelf. This suggests that FA is a contaminant during the manufacturing process and may vary from manufacturer to manufacturer and batch to batch. Until further studies are done to confirm the lack of toxicity to embryos during cryopreservation (with or without FA scavengers) it may be prudent to screen all batches of cryoprotectants for FA as part of quality control.

HN proteins of human parainfluenza type 4A virus expressed in cell lines transfected with a cloned cDNA have an ability to induce interferon in mouse spleen cells.

Primary monkey kidney cells infected with human parainfluenza type 4A virus (HPIV-4A) were treated with various concentrations of formaldehyde. Formaldehyde (0.275%) treatment completely blocked virus production. However, when mouse spleen cells were cocultured with the fixed virus-infected cells, interferon was produced in the culture fluid. On the other hand, when mouse spleen cells were incubated with the fixed virus-infected cells in the presence of anti-HPIV-4A antiserum or a mixture of anti-HN protein monoclonal antibodies, interferon activity could scarcely be detected in the culture fluid. These findings indicated that the fixed virus-infected cells had an ability to induce interferon in mouse spleen cells and that the HN protein was related to interferon induction. Subsequently, a recombinant plasmid was constructed by inserting the cDNA of the HN gene of HPIV-4A into a pcDL-SR alpha expression vector. Mouse spleen cells produced interferon when cocultured with COS7 cells transfected with the recombinant plasmid, but did not when cocultured with COS7 cells transfected with the vector alone. Furthermore, we established HeLa cells constitutively expressing HPIV-4A HN (HeLa-4aHN cells) or F protein (HeLa-4aF cells). Type I (alpha/beta) interferon was detected in culture fluids of mouse spleen cells with HeLa-4aHN cells, but was not detected in those with HeLa-4aF cells. Therefore, it was concluded that the HN glycoproteins on the cell surface were sufficient for interferon induction to occur.

Mast cell response to formaldehyde. 1. Modulation of mediator release.

To examine the effects of the atmospheric pollutant formaldehyde on functionally distinct mast cells, peritoneal mast cells (PMC), intestinal mucosal mast cells (IMMC) and mouse bone-marrow-derived mast cells (BMMC) were incubated with various concentrations of formaldehyde. Pretreatment for 30 min with up to 100 micrograms/ml formaldehyde was not cytotoxic to mast cells. Formaldehyde (1-10 micrograms/ml) alone induced low levels of histamine release (< 10%) from IMMC and BMMC. Antigen-induced histamine release was significantly increased in both PMC pretreated with low concentrations of formaldehyde (5-20 micrograms/ml) and BMMC pretreated with 10 micrograms/ml formaldehyde but decreased in PMC pretreated with a higher concentration (100 micrograms/ml) of formaldehyde. By contrast, antigen-induced histamine release was decreased in IMMC pretreated with formaldehyde in a dose-dependent manner. Histamine release stimulated with A23187 was also increased in PMC pretreated with a low concentration (10 micrograms/ml) of formaldehyde but decreased in those pretreated with a higher concentration (100 micrograms/ml) of formaldehyde. Pretreatment with 10 micrograms/ml formaldehyde significantly enhanced beta-hexosaminidase release from PMC stimulated with antigen or A23187. Compared to sham-treated PMC, PMC pretreated with formaldehyde expressed a markedly depressed natural cytotoxicity for the tumor target WEHI-164 (an assay of tumor necrosis factor alpha activity). These results suggest that formaldehyde modifies various mast cell functions through alterations in cellular metabolism. Such effects may be important in respiratory and other diseases associated with formaldehyde exposure.

The Production of Amitriptyline from Nortriptyline in Formaldehyde-Containing Solutions

The stability of nortriptyline in aqueous solutions containing various concentrations of formaldehyde was investigated. Amitriptyline, as a reaction product, was determined by gas chromatography/mass spectrometry (GC/MS) in these experiments. Factors that may contribute to this phenomenon, including pH, formaldehyde concentration, and incubation time were evaluated. At 40% (v/v) formaldehyde concentration and pH 4, there was a 68% decrease in nortriptyline concentration along with a concomitant formation of amitriptyline after 24 h. The N-methylated product was responsible for 48% of the total tricyclic drug present. The data also clearly indicate that the formation of amitriptyline is favored at elevated pH.

Formaldehyde mutagenesis and formation of DNA-protein crosslinks in human lymphoblasts in vitro

Human lymphoblasts were exposed in vitro to various concentrations of formaldehyde (HCHO) in single and multiple treament regimens to determine relative mutagenic efficiency. Single treatments of HCHO (0–150 μM × 2 h) resulted in a nonlinear increase in induced mutant fraction at the thymidine kinase locus with increasing slope at concentrations above 125 μM. Only HCHO exposures of 125 μM × 2 h or greater produced significant effects on the growth rate of the lymphoblasts. Cultures were also exposed to either three treatments of 50 μM × 2 h, five treatments of 30 μM × 2 h, or ten treatments of 15 μM × 2 h; multiple treatments were administered on different days. These multiple treatments resulted in increases in mutant fraction, although their combined effect was less than a single treatment of equivalent concentration × time (150 μM × 2 h). Exposure of lymphoblasts to four treatments of 150 μM × 2 h HCHO failed to induce mutations at the ouabain resistance locus. Cultures of lymphoblasts receiving a single treatment of HCHO (0–600 μM × 2 h) were analyzed by the alkaline elution technique to detect the presence of DNA-protein crosslinks. HCHO treatment resulted in a significant nonlinear increase in DNA-protein crosslinks at concentrations greater than 50 μM × 2 h, which correlated with the onset of significant toxicity in this cell line. Holding the culture for 24 h resulted in complete removal of the crosslinks. These data indicate that both the induction of mutations and the formation of DNA-protein crosslinks by HCHO are nonlinear functions in human lymphoblasts and occur at overlapping concentration ranges.

Improved utilization of tissue blocks for electron microscopy. Effect of various concentrations of formaldehyde and glutaraldehyde.

Liver tissue from miniature pig fetuses was immersion-fixed in fixative mixtures with various concentrations of formaldehyde and glutaraldehyde. The preservation quality of hepatocytes was evaluated ultrastructurally in a peripheral zone (30--130 micron below the surface) and a central zone (500 micron below the surface). In the peripheral zone the best preservation was obtained with a fixative mixture containing 2% formaldehyde and 2% glutaraldehyde and in the central zone with a fixative mixture containing 8% formaldehyde and 8% glutaraldehyde. It is concluded that a better utilization of fairly large tissue blocks for ultrastructural investigation can be obtained by division of the block and subsequent fixation in fixatives containing various concentrations of formaldehyde and glutaraldehyde.

Sensory irritation to formaldehyde and acrolein during single and repeated exposures in mice.

Mice were exposed to various concentrations of formaldehyde or acrolein. Concentration-response relationships were developed by measuring per cent decrease in respiratory rate, indicating upper respiratory tract sensory irritation. Relationships are presented between the concentration associated with a 50% respiratory decrease and TLVs. A summary of other animal inhalation studies is presented. The basis for the acrolein and formaldehyde TLVs are reviewed. Mice exposed for 4 days showed increasing sensitivity daily for both compounds. A re-evaluation of the TLVs is suggested.

The Timing of Hot‐water Treatment in Controlling Fusarium oxysporum Basal Rot of Narcissas

SUMMARYNarcissus bulbs were treated with various concentrations of formaldehyde in hot water at different times relative to lifting and planting. There was no improvement in control of Fusarium oxysporum basal rot by using formaldehyde concentrations greater than the usual 0.2 percent. The date of treatment was critical, and better control of the disease was obtained by treating in mid‐July than in mid‐August, although flower production in the following season was impaired.

Equilibrium studies on the formaldehyde reaction with native DNA.

Equilibrium analysis of the reaction of formaldehyde with native calf thymus DNA was carried out at temperatures below the thermal transition zone by the spectrophotometric method. The apparent equilibrium constant, Kconf., for the conformational opening and closing reaction of base pairs along the double-helical chain, was measured in various concentrations of formaldehyde, and these values were extrapolated to the zero concentration. The value of KOconf. thus obtained in the absence of the chemical probe was 0.12 in 5 mM 2-(N-morpholino)ethane sulfonic acid buffer (Mes), and 0.003 in 0.15 M NaCl plus 5 mM Mes, pH 7.0, at 50 degrees C. These results make it possible to calculate roughly that 230 base pairs and 7 base pairs are open respectively, at 50 degrees C in the native DNA molecule composed of 2300 base pairs, using Mr = 1.5 x 10(6) for the sample used. This conformational reaction was also characterized by the following thermodynamic parameters: deltaGOconf. = 1.36 kcal - mol-1 (5.68 kJ - mol-1), deltaHOconf. = 36.8 kcal - mol-1 (154 kJ - mol-1), and deltaSOconf. = 110 cal - mol-1 - K-1 (460 J - mol-1 - K-1) in 5 mM Mes, pH 7.0, at 50 degrees C, and the nature of the 'breathing' of base pairs was discussed.

Investigation into the use of Aspergillus oryzae S 1 nuclease in the presence of solvents which destabilize or prevent DNA secondary structure: Formaldehyde, formamide, and glyoxal

The activity of Aspergillus oryzae S 1 nuclease in solutions which destabilize DNA secondary structure was investigated. S 1 nuclease is able to degrade single-stranded DNA in the presence of various concentrations of formaldehyde, formamide, and glyoxal. It is further shown that S 1 nuclease can be used: (1) in the presence of formaldehyde to generate cleavage products from partially denatured duplex DNA; (2) to obtain thermal-melting profiles in the presence of formamide.

Etats du formaldehyde dans l'acide acetique en presence d'acide sulfurique

A quantitative analysis of solutions of formaldehyde in acetic acid has been performed for various concentrations of formaldehyde, sulfuric acid and water, by proton magnetic resonance spectroscopy. In such solutions formaldehyde exists as trioxane and diacetates of methyleneglycol and polyoxymethyleneglycols. These forms of formaldehyde are in equilibria which are discussed.

Peculiarities of the secondary structure of bacteriophage DNA in situ: II. Reaction with formaldehyde

The state of the amino groups of the DNA bases inside phage particles was studied with formaldehyde in experiments of three kinds. In the first set of experiments, phage-dodecyl sulphate complexes were disintegrated in the presence of formaldehyde; and the effect of the latter on the conformational transition of the DNA during its release into the medium was determined. In the second set of experiments, the melting of DNA inside the phage in the presence of various concentrations of formaldehyde was investigated under conditions preventing disruption of the phage particle. Finally, the effect of methylene cross-links on the conformational transition of DNA as well as on its melting point was elucidated in experiments with “fixed” (“formalinized”) phage. A small but definite number of free amino groups, most probably forming small regions with the disordered secondary structure, are thought to be present in DNA inside the phage particle. The rest of the amino groups of the DNA bases inside the phage possess an increased stability to formaldehyde. DNA inside the phage can be characterized according to the melting curves by a considerable loss of co-operativeness in interaction of the bases and by extended phase transition during thermal denaturation.