1,279 research outputs found

    Determination of indoor air quality at the Unlv campus

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    Research on air pollution has gained particular momentum over the past decade. The presence of volatile hydrocarbons, and aldehydes in indoor environments has raised concern about the safety and well-being of personnel exposed to environments containing these pollutants. Because of potential sources of hydrocarbons and formaldehyde, the anatomy lab in the Biology building and the working areas of the Reprographics building on the UNLV campus were singled out for study. Air samples were collected from the Reprographics building for hydrocarbon analysis. A charcoal sorbent tube attached to a commercially available sampler was used for sample collection. Analyses were performed with GC and GC-MS. Data are presented showing the concentration of various hydrocarbons. To determine the concentration of formaldehyde in the Reprographics building and the anatomy lab in the Biology building, air samples were collected in 2,4-dinitrophenylhydrazine (2,4- DNPH) solution (using an impinger) and the concentration of formaldehyde, as the addition product with 2,4-DNPH, was determined by HPLC with UV-VIS detection

    An optical sensor for the sensitive determination of formaldehyde gas based on chromotropic acid and 4-aminoazobenzene immobilized in a hydrophilic membrane

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    Formaldehyde is a common contaminant in occupational and environmental atmospheres, prolonged exposure leads to health risks, and its determination is necessary to protect health. There is a great demand for portable, rapid, and sensitive methods that can be used in resource-limited settings. In this respect, a colorimetric sensor has been developed based on the colour change from pink to purple of co-immobilized chromotropic acid and 4-aminoazobenzene in hydroxypropyl methylcellulose when it is exposed to different concentrations of formaldehyde. The concentration of formaldehyde in the gas phase was quantified by measuring the change of the appropriate colour coordinates in response to the concentration of formaldehyde. A calibration curve was obtained for formaldehyde, with a useful concentration range from 0.08 to 0.6 ppmv. The detection limit was 0.016 ppmv, which is lower than the maximum exposure concentrations recommended by both the World Health Organization (WHO) and the Occupational Safety and Health Administration (OSHA). The optical sensor was found to have good reproducibility, with a relative standard deviation of 2.3 and 1.7% at 0.08 and 0.25 ppmv, respectively. The sensor can operate at room temperature and environmental humidity, 25 °C, and 50% RH, respectively. In addition, a study of interferents (acetaldehyde, toluene, methanol, ethyl acetate, acetone, acetic acid, carbon dioxide and ammonia) showed high selectivity for formaldehyde, which indicates that this membrane is a simple, fast, and economical alternative for quantifying the concentration of formaldehyde in different environments.Spanish “Ministerio de Ciencia e Innovación/Agencia Estatal de Innovación” Project: PID2019-103938RB-I00Spanish “Ministerio de Ciencia e Innovación/Agencia Estatal de Innovación” Project: PID 2021-126579OB-C31Junta de Andalucía Projects: B-FQM-243-UGR18 and P18-RT-296

    Formaldehyde exposure induces histopathological and morphometric changes in the rat testis

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    Formaldehyde is a chemical which is traditionally used for fixing cadavers and routine histopathology techniques. It is vaponsed during the dissection and practical study of a cadaver. Previous studies have shown that this vapour may cause clinical symptoms such as throat, eye, skin and nasal irritation. This study was designed to determine the histopathology and morphometrics of the rat testis when all the experimental animals were exposed to formaldehyde for 18 weeks. The study was performed in 2004 on 28 albino Wistar rats of 6-7 postnatal weeks. The rats were divided into three case groups (E1: 4 h/d, 4 d/w; E2: 2 h/d, 4 d/w; E3: 2 h/d, 2 d/w) and one control group. The testes specimens were sectioned at 5 μm and stained with the haematoxylin and eosin staining technique for histological and morphometrical studies. We found a severe decrease in germ cells associated with spermatogenesis arrest in the E1 group. A decrease in germ cells and a thickening of the basal membrane of the seminiferous tubules were seen in E2. Displacement of Sertoli and germinal cells were also found in the E3 group. The mean seminiferous tubular diameter and seminiferous epithelial height in the experimental groups were decreased in comparison with the control group and the differences were statistically significant (p < 0. 05). The findings of this study revealed that chronic formaldehyde exposure can cause histopathological and morphometric changes to the seminiferous epithelium in rats and that these changes depend on the duration of the formaldehyde exposure. Copyright © 2007 Via Medica

    Volatile aldehydes in libraries and archives

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    Volatile aldehydes are produced during degradation of paper-based materials. This may result in their accumulation in archival and library repositories. However, no systematic study has been performed so far. In the frame of this study, passive sampling was carried out at ten locations in four libraries and archives. Despite the very variable sampling locations, no major differences were found, although air-filtered repositories were found to have lower concentrations while a non-ventilated newspaper repository exhibited the highest concentrations of volatile aldehydes (formaldehyde, acetaldehyde, furfural and hexanal). Five employees in one institution were also provided with personal passive samplers to investigate employees’ exposure to volatile aldehydes. All values were lower than the presently valid exposure limits. The concentration of volatile aldehydes, acetic acid, and volatile organic compounds (VOCs) in general was also compared with that of outdoor-generated pollutants. It was evident that inside the repository and particularly inside archival boxes, the concentration of VOCs and acetic acid was much higher than the concentration of outdoor-generated pollutants, which are otherwise more routinely studied in connection with heritage materials. This indicates that further work on the pro-degradative effect of VOCs on heritage materials is necessary and that monitoring of VOCs in heritage institutions should become more widespread

    Can formaldehyde exposure induce histopathologic and morphometric changes on rat kidney? [¿la exposición al formaldehído puede inducir cambios histopatológicos y morfométricos sobre el riñón de rata?]

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    Formaldehyde is used traditionally for fixing the cadaver, and vaporized during dissection and practical studying on cadaver. This study was designed to determine the histopathologic and morphometric changes of rat kidney while all of the experiments were exposed to formaldehyde for 18 weeks. 28 male albino Wistar rats were divided into the following three experimental groups (E1: 2hrs/d, 2d/w; E2: 2hrs/d, 4d/w; E3: 4hrs/d, 4d/w) and one control group (C). when the exposure period was expired the animals were anaesthetized with chloroform. After cervical dislocation, the abdomen was dissected and the kidneys were taken. The kidney specimens were sectioned and stained with Haematoxylin and Eosin technique for histologic and morphometric study. Data were obtained from an Olympus light microscope and the analyzed with spss (version 11.5) and ANOVA test. In all histopathology sections of groups E1, E2 and E3, these similar changes were seen: mild glumerolar congestion, focal congestion, and vacuolar degeneration of tubular cells. There were no evidences of inflammatory cells infiltration or fibrotic changes of interstitial tissue. Only mild, non-specific congestion was seen in cortical vessels. Also there were not any abnormalities in the staining of nucleus and cytoplasm. According to Morphometric study, Mean ±SD of glomerulus's area in control, E1, E2 and E3 group were 10802.66±1038.18, 10759.50±1971.88, 10434.73±1763.76 and 10077.64±2068.78 micrometer, respectively. Mean ±SD inner proximal tubule diameter in control, E1, E2 and E3 group were 16.16±2.49, 16.92±2.90, 16.31±2.79 and15.66±4.11 μm, respectively. Mean ±SD of inner distal tubule diameter in control, E1, E2 and E3 group were 15.96±4.47, 16.20±1.66, 16.96±1.63 and17.45±3.26 μm, respectively. These differences were not significant between cases and control. This study showed that formaldehyde inhalation in 1.5 ppm can not make specific Histopathologic and Morphometric changes in rat kidney

    Formaldehyde-releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers

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    This is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed in the literature as formaldehyde-releasers, data are inadequate to consider them as such beyond doubt. Several (nomenclature) mistakes and outdated information are discussed. Formaldehyde and formaldehyde allergy are reviewed: applications, exposure scenarios, legislation, patch testing problems, frequency of sensitization, relevance of positive patch test reactions, clinical pattern of allergic contact dermatitis from formaldehyde, prognosis, threshold for elicitation of allergic contact dermatitis, analytical tests to determine formaldehyde in products and frequency of exposure to formaldehyde and releasers. The frequency of contact allergy to formaldehyde is consistently higher in the USA (8-9%) than in Europe (2-3%). Patch testing with formaldehyde is problematic; the currently used 1% solution may result in both false-positive and false-negative (up to 40%) reactions. Determining the relevance of patch test reactions is often challenging. What concentration of formaldehyde is safe for sensitive patients remains unknown. Levels of 200-300 p.p.m. free formaldehyde in cosmetic products have been shown to induce dermatitis from short-term use on normal skin

    The oxidative dehydrogenation of methanol to formaldehyde over silver catalysts in relation to the oxygen-silver interaction

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    The properties of silver in the oxidative dehydrogenation of methanol were studied in a flow reactor under near industrial conditions. The influences of temperature, concentration of both reactants, gas velocity, space velocity, the form of the silver catalyst and surface composition of the catalyst were studied. A model for the reaction is proposed which is based on the experimental observations and on the nature of the interaction of silver with oxygen. It issuggested that different oxygen species on the silver surface play different roles in the reactions to CO, CO2 and H2CO. Gas phase reactions only contribute to the conversion to CO

    Ultraviolet Spectrophotometric Method for Determination of Gelatin Crosslinking in the Presence of Amino Groups

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    The study was carried out to develop procedure for determining concentration of formaldehyde to be used for crosslinking of gelatin in the presence of drugs having amino groups. Gentamicin sulfate was used as a drug candidate due to its high content of amino acids. Gelatin crosslinking is accelerated by aldehyde-containing compounds and inhibited by amino group-containing compounds. The major modifications from already existing procedures are that the trinitrobenzenesulphonic acid (TNBS) reaction is used to detect e-amino groups of Type A gelatin in the presence of formaldehyde and further it is supported with colorimetric analysis of free formaldehyde content using a chromotropic acid regent. Since formaldehyde crosslinks amino groups, the TNBS assay can be effectively utilized for determination of complete crosslinking of gelatin with analysis of free amino acid content in crosslinked formulation. The effect of the presence of amino groups on gelatin crosslinking was estimated in the presence of gentamicin sulfate. The ε-amino content of uncrosslinked Type A gelatin was found to be 28.6 mol/gelatin molecule of 1000 residues and in case of crosslinked gelatin it varies with varying concentration of formaldehyde. The procedure stated here should be applicable to a broad range of drugs containing amino groups which are used along with gelatin or other proteinaceous materials which are applicable after crosslinking with formaldehyde