High Concentrations Of Formaldehyde Research Articles

Formaldehyde Exposure of Aquaculture Workers in Korea

ABSTRACT Objectives Korea’s aquaculture sector primarily cultivates aquatic life, with fish seed production as a focus. Formalin, a parasiticide, consists of 37% formaldehyde mixed with yellow No. 4 dye. Formaldehyde vaporization poses cancer risks, classified as a carcinogen. Korea regulates formaldehyde as a hazardous substance, requiring workplace environment measurements. Few aquaculture farms have conducted these checks in recent years. In this study, we investigated actual formaldehyde exposure levels among Korean aquaculture workers, highlighting a critical safety concern. Methods A field survey was conducted to measure formaldehyde exposure at 10 aquaculture farms in areas where Korean aquaculture is concentrated. Short-term and long-term personal samples, local samples, and direct-reading measurements were conducted. Formaldehyde exposure levels were detected in short-term personal samples from six farms and in long-term personal samples from two farms, and formaldehyde was detected in all local samples. In direct-reading measurements, a high concentration of formaldehyde was sustained for short periods. Results Long-term (8-hour) personal samples were mostly non-detectable, except for farms A and D, which had levels of 0.0009 ppm and 0.0017 ppm, respectively. Short-term (15-minute) samples were non-detectable in four farms, with an average of 0.0158 (±0.0130) ppm in the remaining six farms. Local samples from all farms had an average of 0.0384 (±0.0957) ppm of formaldehyde. For farms A and D, where long-term sampling detected formaldehyde, real-time measurements showed a sustained high concentration in farm A for about 48 minutes before decreasing. Farm D had no detectable formaldehyde throughout the monitoring period. Conclusion According to the formaldehyde exposure level assessment, short term exposure to formaldehyde during and immediately after application of formalin nearly exceeded the ACGIH TLV STEL in one farm. However, concentration of long term samples appeared at 10% of ACGIH TLV TWA. Additional study is recommended to determine whether exposure to formaldehyde poses a health risk for aquaculture workers during application of formalin.

Spatial modeling of air pollution in Kharkiv city


 
 
 One of the most pressing problems facing cities, which negatively affects public health. There is a global practice of online monitoring of the content of pollutants in the air of settlements and informing the population about dangerous periods of increased pollution concentrations for certain categories of diseases and the population as a whole. It is also likely that one of the factors of pollution spread is the landscape differentiation of the city’s territory. The purpose of the study presented in this article is to develop statistical and cartographic models of the spatial distribution of air pollutants within the city of Kharkiv and to establish the relationship between the degree of air pollution and types of urban landscapes. Methods. Based on the analysis of the main methodological approaches and tasks of cartographic modeling of the spatial distribution of air pollution, the study substantiates the choice of the modeling method in this study; the features of a large city as an object of cartographic modeling of air pollution are assessed. Results. Based on the results of long-term monitoring by the Kharkiv Regional Center for Hydrometeorology, a statistical analysis of the results of the maximum and average content of pollutants in the atmosphere of Kharkiv was made and the spatial distribution of air pollution in Kharkiv (including (dust, carbon monoxide, nitrogen dioxide, sulfur dioxide, formaldehyde) was modeled, and patterns of pollution distribution were identified according to landscape types. Conclusions. In general, the spatial analysis of pollutant concentrations in the territories of Kharkiv showed that, in terms of maximum concentrations, the southeastern part of Kharkiv is most affected by carbon monoxide, nitrogen dioxide, and formaldehyde. The reason for this is the large area of industrial facilities. The northwestern part of the city has the highest concentrations of dust and sulfur dioxide. There is a lowering of the relief in the floodplain type of landscape and dense development. Intensive traffic and lowered relief (floodplain landscape) cause high average concentrations of dust, carbon monoxide, and sulfur dioxide in the southern part of the city. Nitrogen dioxide concentrations exceed the TLK in the northwest. The reason is the lowering of the relief on the outskirts of the city (floodplain landscape). The central part of the city has a high average concentration of formaldehyde. In general, a pattern of high concentrations of pollutants was found on the floodplains of the Lopan and Kharkiv rivers, with the lowest concentrations confined to watershed types of terrain between the Kharkiv and Lopan rivers and the Udy and Lopan rivers.
 
 

Fluid preservation in brain banking: a review.

Fluid preservation is nearly universally used in brain banking to store fixed tissue specimens for future research applications. However, the effects of long-term immersion on neural circuitry and biomolecules are not well characterized. As a result, there is a need to synthesize studies investigating fluid preservation of brain tissue. We searched PubMed and other databases to identify studies measuring the effects of fluid preservation in nervous system tissue. We categorized studies based on the fluid preservative used: formaldehyde solutions, buffer solutions, alcohol solutions, storage after tissue clearing, and cryoprotectant solutions. We identified 91 studies containing 197 independent observations of the effects of long-term storage on cellular morphology. Most studies did not report any significant alterations due to long-term storage. When present, the most frequent alteration was decreased antigenicity, commonly attributed to progressive crosslinking by aldehydes that renders biomolecules increasingly inaccessible over time. To build a mechanistic understanding, we discuss biochemical aspects of long-term fluid preservation. A subset of lipids appears to be chemical altered or extracted over time due to incomplete retention in the crosslinked gel. Alternative storage fluids mitigate the problem of antigen masking but have not been extensively characterized and may have other downsides. We also compare fluid preservation to cryopreservation, paraffin embedding, and resin embedding. Overall, existing evidence suggests that fluid preservation provides maintenance of neural architecture for decades, including precise structural details. However, to avoid the well-established problem of overfixation caused by storage in high concentration formaldehyde solutions, fluid preservation procedures can use an initial fixation step followed by an alternative long-term storage fluid. Further research is warranted on optimizing protocols and characterizing the generalizability of the storage artifacts that have been identified.

Анализ зависимости между погодными условиями и качеством атмосферного воздуха в городах Казахстана за 11-летний период (2010–2020 гг.) как основа эпидемиологических рисков

In this study, a retrospective analysis of the relationship between weather conditions and the presence of pollutants in the airspace of the city of Karaganda and Petropavlovsk for an 11-year period (2010-2020) was carried out. The dynamics of the air pollution code of the studied cities indicated a higher level of air pollution in the city of Karaganda throughout all seasons, compared with the indicators of the city of Petropavlovsk. Substances belonging to the first hazard category significantly prevailed in gaseous emissions in the city of Karaganda: nitrogen dioxide in winter, ozone in spring and summer. Phenols and formaldehyde were present in the air of Karaganda during all seasons, significantly exceeding the MPC. An analysis of the correlations between weather and nvironmental factors made it possible to find medium and weak direct and inverse correlations between atmospheric pollution, weather conditions and seasons. It was found that in the winter season, synergism could manifest itself due to the simultaneous presence of nitrogen dioxide and formaldehydes, the content of which in the atmosphere significantly exceeded the MPC. In the summer season, synergy could be expected due to the simultaneous presence of high concentrations of ozone and formaldehyde in the air. The complex impact of weather conditions, the level and nature of air pollution in the Karaganda region compared to the city of Petropavlovsk indicates the likelihood of a significant increase or modification of negative consequences for human health.

Biodegradation enhancement of high concentrations formaldehyde waste gas and verification of the metabolic mechanism

The enhanced effects of formaldehyde biodegradation in a biofilm packing tower are investigated in this study. Three experimental groups were established: a blank control group, a biochar addition group, and a lanthanum addition group. The inlet gas flow rate, the inlet gas concentration, and the structural succession characteristics of the microbial community in the tower were investigated by regular sampling. The intracellular metabolites and key enzymes of the dominant functional bacteria, Pseudomonas P1 and Methylobacterium Q1, in the tower were analyzed. The results indicated that with the biochar addition, the formaldehyde purification efficiency increased significantly from 91.67–94.67 % to 94.12 96.85 %, and the bio-elimination capacity increased with an increase in the inlet gas flow rate from 2.314 to 13.988 mg L−1h−1 to 2.697–15.051 mg L−1h−1. With the addition of lanthanum, the purification efficiency increased significantly from 90.80–93.98 % to 94.36–96.78 %, and the bio-elimination capacity increased with an increase in the inlet gas concentration from 1.099–11.284 mg L−1h−1 to 1.266–11.961 mg L−1h−1. The microbial community structure in the tower changed with system operation, and the formaldehyde degrading functional bacteria formed the dominant bacteria. It was verified that P1 and Q1 metabolized high concentrations of formaldehyde by the serine cycle and the ribulose monophosphate (RuMP) cycle.

The influence of air pollutants on COVID-19 severity in the administrative and industrial city of Kharkiv

Background. Despite the official statement by the World Health Organization regarding the end of coronavirus disease (COVID-19) pandemic, the risk of an epidemic rise in morbidity remains due to the active circulation of the pathogen and its mutation. Social, natural, environmental, and other factors can contribute to the spread of COVID-19. Air pollutants are extremely dangerous for humans, and a mixture of aerosols and dust particles in the air can serve as factors for the severe acute respiratory syndrome coronavirus 2 transmission. So, the purpose of the study was to reveal the impact of air pollutants on COVID-19 severity in Kharkiv. Materials and methods. The influence of environmental factors on the manifestations of COVID-19 epidemic was assessed for 425 days. 16,723 cases of hospitalizations, 1,883 deaths, and 15,146 confirmed cases of COVID-19 in various age groups were studied. There were on average 4,663 active cases every day. Statistical analysis on assessing the impact of environmental factors on COVID-19 morbidity with different degrees of severity was performed using the non-parametric Kruskal-Wallis test in the IBM SPSS Statistics software package, and the normality of the distribution was checked using the Kolmogorov-Smirnov test. Microsoft Office Excel 2016 spreadsheet tools were used for some auxiliary calculations and graphing. Results. The influence of sulfur dioxide, nitrogen dioxide, nitrous oxide, hydrogen sulfide, phenol, soot, and formaldehyde on COVID-19 morbidity in different severity of infection course with incubation periods of 3–4, 6–7, and 10–14 days was revealed. The effect of high concentrations of nitrogen dioxide, nitrogen oxide, and formaldehyde was most significant on active, confirmed, hospitalized, and fatal cases of COVID-19. At the same time, a rise in active cases of COVID-19 was observed with increasing concentrations of sulfur dioxide and hydrogen sulfide, and high concentrations of phenol and soot had an impact on severe forms. Conclusions. Air pollution can contribute to the spread of COVID-19 and lead to its severe forms, which should be considered when predicting morbidity at different levels (national, regional, local) of epidemiological surveillance. Further research is needed to reveal causal relationships between the incidence of COVID-19 and air pollutants, considering the influence of social and natural factors.

Formaldehyde induced the cardiac damage by regulating the NO/cGMP signaling pathway and L-Ca2+ channels.

Formaldehyde (FA) is a common environmental pollutant that has been found to cause negative cardiovascular effects, however, the toxicological mechanism is not well understood. In this study, we investigated the molecular effects of the Nitric Oxide (NO)/cyclic Guanosine Monophosphate (cGMP) signaling pathway and L-type calcium (L-Ca2+) channels in rat hearts. We designed the short-term FA exposure on the rat heart in different concentrations (0, 0.5, 3, 18 mg/m3). After 7 days of exposure, the rats were sacrificed and the rat tissues were removed for various experiments. Our experimental data showed that FA resulted in the upregulation NO and cGMP, especially at 18 mg/m3. Further, when exposed to high concentrations of FA, Cav1.2 and Cav1.3 expression decreased. We conclude that the NO/cGMP signaling pathway and downstream related channels can be regulated by increasing the production of NO in the low concentration group of FA. High concentration FA directly regulates L-Ca22+ channels. This study suggests that FA damages the function of the cardiovascular system by regulating the NO/cGMP signaling pathway and L-Ca2+ channels.

Epigenomic analysis of formalin-fixed paraffin-embedded samples by CUT&Tag

For more than a century, formalin-fixed paraffin-embedded (FFPE) sample preparation has been the preferred method for long-term preservation of biological material. However, the use of FFPE samples for epigenomic studies has been difficult because of chromatin damage from long exposure to high concentrations of formaldehyde. Previously, we introduced Cleavage Under Targeted Accessible Chromatin (CUTAC), an antibody-targeted chromatin accessibility mapping protocol based on CUT&Tag. Here we show that simple modifications of our CUTAC protocol either in single tubes or directly on slides produce high-resolution maps of paused RNA Polymerase II at enhancers and promoters using FFPE samples. We find that transcriptional regulatory element differences produced by FFPE-CUTAC distinguish between mouse brain tumors and identify and map regulatory element markers with high confidence and precision, including microRNAs not detectable by RNA-seq. Our simple workflows make possible affordable epigenomic profiling of archived biological samples for biomarker identification, clinical applications and retrospective studies.

Is There a Formaldehyde Deficit in Emissions Inventories for Southeast Michigan?

Formaldehyde is a key Volatile Organic Compound (VOC) and ozone precursor that plays a vital role in the urban atmospheric radical budget on par with water vapor, ozone, and nitrous acid. In addition to modulating radical and ozone production, ambient formaldehyde has both carcinogenic and non-carcinogenic inhalation health effects. This study concludes that ambient formaldehyde in the Southeast Michigan (SEMI) ozone nonattainment area may be underestimated up to a factor of two or more by regional air quality models. The addition of plausible amounts of primary formaldehyde to the U.S. National Emissions Inventory based on estimated formaldehyde-to-CO emission ratios partially alleviates this modeling deficit and indicates the presence of formaldehyde concentrations above 5 ppb at a previously unsuspected location northeast of Detroit. Standard 24-h formaldehyde samples obtained during the Michigan-Ontario Ozone Source Experiment (MOOSE) verified the presence of high ambient formaldehyde concentrations at this location. Moreover, the addition of plausible amounts of primary formaldehyde to VOC emissions inventories may add more than 1 ppb of ozone to ambient air in the SEMI nonattainment area, where ozone design values exceeded the U.S. National Ambient Air Quality Standard (NAAQS) by 1–2 ppb for the 2018–2020 design value period.

Formaldehyde Gas Sensing Characteristics of ZnO-TiO2 Gas Sensors

Since the increase in the emission of various Volatiles Organic Compounds, gas and formaldehyde gas have had a harmful effect on the human body, and gas sensors that can measure those gases were fabricated in this study. After Pt coating was performed on the alumina substrate, Zn seed layers were fabricated. Nanostructures were formed through sonochemical synthesis by varying the ratio of ZnO and TiO2. Thereafter, the reactivity and recovery properties were compared and evaluated according to the concentrations of formaldehyde and toluene gas. The ZnO(99%)-TiO2(1%) gas sensor showed meaningful selectivity of about 40% or more at a concentration ranging from 5 to 20 ppm (high concentration) of formaldehyde and toluene gas, and showed a low selectivity of about 5% or more for a concentration ranging from 0.1 to 1 ppm (low concentration) of formaldehyde and toluene gas. This sensor can be optimized to have a meaningful selectivity of formaldehyde gas compared to other Volatiles Organic Compounds gases by optimizing the ZnO-TiO2 nanostructure.

The structure of diseases leading to the death of dogs and cats in the ecological conditions of the city of Irkutsk

For all industrial cities, the problem of the impact of habitat on animal health is relevant. Studies conducted in the environmental conditions of the city of Irkutsk in the period from 2018 to 2020 allowed us to establish that its atmospheric air contains high concentrations of benz(a)pyrene, formaldehyde and nitrogen dioxide. The maximum average daily concentration of potentially carcinogenic heavy metals was exceeded in all snow samples. During the period under review, a fatal outcome was recorded in 3967 cases in dogs and in 3024 cases in cats. The structure of diseases that caused the death of animals is dominated by diseases of non-infectious origin, among which tumor pathology took the first place in dogs. Diseases of the cardiovascular and respiratory systems, as well as injuries, gunshot wounds and bites were among the leading ones. In cats, cancer, urinary tract diseases, cardiovascular and respiratory diseases were noted as the leading causes of death. The largest number of dogs and cats who died from cancer and diseases of the cardiovascular and respiratory systems lived in the central part of the city with the most polluted surface layer of the atmosphere.

Determination of methanol-derivatives in drying oils after metal oxide-based dispersive solid phase extraction/QuEChERS clean-up

The determination of secondary volatile degradation products in drying oil extracts is substantial to prevent formation of undesirable metal formates in paintings and/or other artefacts. This study develops a simple, cost-effective, and reliable, high-performance liquid chromatography with diode array detector (HPLC–DAD) method to determine three secondary volatile degradation products (methanol, formaldehyde, and formic acid) in drying oils, including linseed, poppy-seed, and walnut oil. Extraction of analytes was performed using QuEChERS-based procedure followed by metal oxide-based dispersive solid-phase extraction (d-SPE) clean-up and presented a good performance for all of the volatile analytes of interest with recoveries in the range of 90–120% after application of the nanostructured cerium oxide-based (CeO2) and zirconia-based (ZrO2) sorbents prepared by favorable and ecological-friendly methods. With a new clean-up solution for samples with high-fat content, it was possible to achieve higher recoveries than with commercial Z-Sep/C18 sorbent. In all cases, relative standard deviations (RSD) of less than 10% were achieved. No significant matrix interference was observed due to the application of effective sorbents in nanostructured form. The developed method was applied to samples of drying oils, and it was found that after storage for three months, all methanol was most likely oxidized to formaldehyde and formic acid. The concentrations of formaldehyde were in the range of 260 - 304 μg∙g−1, while formic acid concentrations ranged between 72 - 386 μg∙g−1. The highest concentration of formaldehyde (304 μg∙g−1) and formic acid (386 μg∙g−1) was found in linseed oil.

Impact of glycol-based solvents on indoor air quality-Artificial fog and exposure pathways of formaldehyde and various carbonyls.

Artificial fog is commonly employed in the entertainment industry and indoor household celebrations. The fog is generated from glycol-based solvents, which can also be found in e-cigarettes and personal care products. Although potential health impacts of glycol inhalation are frequently cited by studies of e-cigarette smoking, the dynamics and the chemical composition of glycol-based aerosols have never been studied systematically. The objective of this work is to investigate the impact of glycol-based aerosol on indoor air quality. Specifically, we targeted artificial fogs generated with common glycols, including propylene glycol (PG) and triethylene glycol (TEG). With the aid of a novel aerosol collecting and monitoring instrument setup, we obtained time-resolved aerosol profiles and their chemical compositions in an experimental room. Artificial fog has given rise to a significant amount of ultra-fine particulate matter, demonstrating its negative impact on indoor air quality. Additionally, we found a high concentration (9.75 mM) of formaldehyde and other carbonyls in fog machine fluids stored for months. These compounds are introduced to the indoor air upon artificial fog application. We propose that carbonyls have accumulated from the oxidative decomposition of glycols, initiated by OH radicals and singlet oxygens (1 O2 ) and likely sustained by autooxidation. Oxidation of glycols by indoor oxidants has never been reported previously. Such chemical processes can represent an unrecognized source of toxic carbonyl compounds which is also applicable to other glycol-based solvents.

Emission of Dust and VOCs as Burning Incense Under Ventilation Conditions

This study determined emissions of incense burning, a traditional worship activity in Asian countries, under different ventilation conditions. The experiments were conducted in a chamber with a volume of 1 m3 (1´1´1 m3) without ventilation or under mechanical ventilation (6 m3/h). There were four different types of traditional and aromatic incense in terms of length (in centimeter) and color, including 27.0 cm (traditional Inc1 - yellow), 21.5 cm (aromatic Inc2 - brown), 30.0 cm (aromatic Inc3 - dark yellow) and 19.0 cm (traditional Inc4- dark red color). The incence was placed and lighted at 0.5 m in height inside of the chamber. PM10 and PM2.5 were directly monitored in the whole process of incense burning using Air Quality Detector (GM8803 and SIBATA - LD-5R) at the same position of 0.5m in height. VOCs was measured by chromatography at three different periods, i.e., before the incense was lighted, during the process of burning, and after the incense burned out. Study results showed that the variation of PM concentrations was separated into three phases: (p1) PM concentrations quickly increased within 15 minutes after being lighted, (p2) PM concentrations were stable from 20 minutes to 35 minutes, (p3) PM concentrations decreased gradually. The maxinum concentrations of PM10 without ventilation for Inc1, Inc2, Inc3, Inc4 were 2138, 2293, 2259, 2210 µg/m3, respectively; and they decreased about 40-70% under ventilation. The maxinum PM2.5 concentrations were about 870-1210 µg/m3 under ventilation or without ventilation. VOCs ended up no Benzen emissions with all the types of experimental incense. Inc1 emitted HCHO concentrations from 4.8 ppm to 5.4 ppm, which was one of the two types containing highest concentrations of Formaldehyde. Meanwhile, Inc3 emitted the lowest VOCs concentrations among the three remaining types, and no Toluen was detected, which showed the optimum effect of clean incense in comparison with traditional one. Key words: incense, VOC, particulate matter, ventilation, indoor pollution

Kinetic modeling of binary mixture of butyraldehyde and acetone with generated by-products in photocatalytic oxidation reactor

This research reports the development of a kinetic model to predict binary mixture degradation and by-product generation in a continuous flow Photocatalytic Oxidation (PCO) reactor. Butyraldehyde and acetone were chosen as a binary VOC mixture to validate the model using experiments conducted with a photocatalyst (TiO2 coated on silica fibers) under various concentration levels (0.1–1 ppm), concentration ratios of target compounds in the mixture (0.5–2), relative humidity levels (17–70%), irradiations (7–23.5 W/m2), and airflow rate (10–30 L/min). Formaldehyde, acetaldehyde, propionaldehyde, butyric acid, propionic acid, and acetic acid were detected as by-products, in which aldehydes had a higher quantity. Carbon balance analysis showed that butyraldehyde and binary mixtures mineralized into carbon dioxide at rates of 19% and 12.8%, respectively. Also, 24% of butyraldehyde and 10% of binary mixture were converted to by-products. Among three proposed scenarios for PCO reaction rate of butyraldehyde, the one including conversion of butyraldehyde directly towards propionaldehyde, acetaldehyde, and formaldehyde, provided the most accurate rate model (R2 = 0.98). Due to its faster reaction rate, butyraldehyde demonstrated a higher degradation efficiency than acetone in the binary mixture. At a constant butyraldehyde concentration, lowering the ratio of butyraldehyde/acetone to 0.5 resulted in the reduction of removal efficiency of butyraldehyde and an increase in concentration of acetaldehyde in air than other by-products. Conversely, enhancing this ratio to 2, led to improved removal efficiency of both butyraldehyde and acetone in the mixture and higher concentration of formaldehyde. Increases in air relative humidity level and velocity resulted in an increase in the outlet concentration of challenge compounds but reduced the formation of all by-products. However, raising the irradiation increased the degradation efficiency of butyraldehyde and binary mixture and, consequently, elevated the formation of by-products. The developed model was capable of properly predicting the concentration of the challenge compounds and their by-products in a binary mixture at different operating conditions.

Network-based integrated analysis for toxic effects of high-concentration formaldehyde inhalation exposure through the toxicogenomic approach

Formaldehyde is a colorless, pungent, highly reactive, and toxic environmental pollutant used in various industries and products. Inhaled formaldehyde is a human and animal carcinogen that causes genotoxicity, such as reactive oxygen species formation and DNA damage. This study aimed to identify the toxic effects of inhaled formaldehyde through an integrated toxicogenomic approach utilizing database information. Microarray datasets (GSE7002 and GSE23179) were collected from the Gene Expression Omnibus database, and differentially expressed genes were identified. The network analyses led to the construction of the respiratory system-related biological network associated with formaldehyde exposure, and six upregulated hub genes (AREG, CXCL2, HMOX1, PLAUR, PTGS2, and TIMP1) were identified. The expression levels of these genes were verified via qRT-PCR in 3D reconstructed human airway tissues exposed to aerosolized formaldehyde. Furthermore, NRARP was newly found as a potential gene associated with the respiratory and carcinogenic effects of formaldehyde by comparison with human in vivo and in vitro formaldehyde-exposure data. This study improves the understanding of the toxic mechanism of formaldehyde and suggests a more applicable analytic pipeline for predicting the toxic effects of inhaled toxicants.

A Field Study on Volatile Organic Compounds Generated During Cooking in a Large Pot Using PTR ToF MS

Various volatile organic compounds (VOCs), including aldehydes, are present in fried food being cooked in high-temperature oil. In this study, real-time VOC concentration was measured in the upper part of a large pot in the cooking room using Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR ToF MS) for 3 days (roasted on the first day, fried on the second day, and simmered on the third day). The average concentration of diacetyl was the highest on the first day of stir-frying and steaming. The highest concentrations of formaldehyde was on day 3 when pork was cooked in sugar and sauce. Formaldehyde, 1,3-butadiene, acrolein, diacetyl, and naphthalene were detected during the frying process on the second day, and were detected in descending order of boiling point. In addition, various VOCs such as methanol were detected. The maximum/minimum concentration ratio was the highest for acrolein (3,030), so it was confirmed that many aldehydes were generated during frying. Although there is a limit to direct comparison with Occupational Exposure Limit as a result of area sample by PTR ToF MS, the mean concentrations of formaldehyde and diacetyl during the frying operation for 15 minutes were 232 ppb and 16 ppb, respectively, which was 80% of the American Conference of Governmental Industrial Hygienists Threshold Limit Value-Short Term Exposure Limit. After the frying was over, the VOC concentration began to decrease, and it took more than 3 hours to lower the VOC concentration to the level before the oil was heated. As various harmful gaseous substances are generated when cooking deep-frying, improvement methods such as using oil with high boiling points and developing respiratory protection programs should be devised.

Psoriasiform skin reaction due to Brazilian keratin treatment: A clinical-dermatoscopic study of 43 patients.

Introduction:Hair straightening products like the Brazilian Keratin Treatment (BKT) contain high concentrations of formaldehyde, and its use is associated with adverse effects. In 2016, seven cases of eczema-like psoriasiform skin reaction secondary to BKT were described for the first time. We aim to investigate the clinical characteristics and dermatoscopic findings of patients with psoriasiform skin reactions due to BKT.Materials and Methods:A cross-sectional study was performed from October 2017 to June 2020. Patients who developed erythema and scales on the scalp following the use of BKT were included. Age, sex, number of BKTs, time elapsed between BKT and the skin reaction, pull test, and dermatoscopic findings were investigated. Descriptive and inferential statistics were used.Results:We found 43 patients with a mean age of 35 ± 10 years, predominantly females in 42 (98%) cases. The mean number of BKTs was 2 ± 2. The mean length of time elapsed to present the reaction was 12 ± 17 months and this was related to the number of BKTs (P = 0.01). The pull test was positive in 37 (86%) patients. The most frequent dermatoscopic findings were perifollicular scales in 42 (98%), red patches in 35 (81%), and peripilar desquamation resembling the outer skin of an onion bulb in 32 (74%).Conclusion:Hair straightening products are widely used and the psoriasiform skin reaction that develops afterward might be underdiagnosed. It is important to investigate the background of BKT in conjunction with the clinical and dermatoscopic findings suggestive of this cutaneous reaction.

Advanced oxidation of high concentrations of formaldehyde in aqueous solution under fluorescent and UV light

Background: Formaldehyde (FA) is a carcinogen compound, which is soluble in water. FA can be removed from aqueous solution using advanced oxidation methods. Methods: In this study, the oxidation of FA was studied under fluorescent and UV light. Hydrogen peroxide (H2 O2 ) was used as an oxidant. The pH value and H2 O2 amount of samples were optimized. The chemical oxygen demand (COD), FA concentration, and H2 O2 consumption were followed. Results: It was observed that the pH value of the sample was more significant under fluorescent light than UV light at oxidation of FA. The highest COD removal and H2 O2 reduction were 18.57 and 30.90%, respectively, at pH 12.00, with a 1:1 ratio of FA:H2 O2 under fluorescent light. 86.41% FA and 62.12% COD removal were achieved at pH 7.00, with a 1:2 ratio of FA:H2 O2 , under UV light. It was observed that H2 O2 was consumed at all pH values under UV light. On the other hand, under fluorescent light, the concentration of H2 O2 decreased only at pH 12. In control samples containing only H2 O2 , the H2 O2 reduction was 92.09% at pH 11.91, while it was 2-6% at other pH levels under fluorescent light. The H2 O2 reduction changed between 33 and 44% at different pH values under UV light. The oxidation of FA was found to be suitable for the pseudo-first-order kinetic model and Langmuir isotherm model. Conclusion: The most effective oxidation was obtained at the original pH value (7.00) and 1:2 ratio of FA:H2 O2 under UV light.

Improvement of glycine biosynthesis from one-carbon compounds and ammonia catalyzed by the glycine cleavage system in vitro.

Glycine cleavage system (GCS) plays a central role in one‐carbon (C1) metabolism and receives increasing interest as a core part of the recently proposed reductive glycine pathway (rGlyP) for assimilation of CO2 and formate. Despite decades of research, GCS has not yet been well understood and kinetic data are barely available. This is to a large degree because of the complexity of GCS, which is composed of four proteins (H, T, P, and L) and catalyzes reactions involving different substrates and cofactors. In vitro kinetics of reconstructed microbial multi‐enzyme glycine cleavage/synthase system is desired to better implement rGlyP in microorganisms like Escherichia coli for the use of C1 resources. Here, we examined in vitro several factors that may affect the rate of glycine synthesis via the reverse GCS reaction. We found that the ratio of GCS component proteins has a direct influence on the rate of glycine synthesis, namely higher ratios of P protein and especially H protein to T and L proteins are favorable, and the carboxylation reaction catalyzed by P protein is a key step determining the glycine synthesis rate, whereas increasing the ratio of L protein to other GCS proteins does not have significant effect and the ratio of T protein to other GCS proteins should be kept low. The effect of substrate concentrations on glycine synthesis is quite complex, showing interdependence with the ratios of GCS component proteins. Furthermore, adding the reducing agent dithiothreitol to the reaction mixture not only results in great tolerance to high concentration of formaldehyde, but also increases the rate of glycine synthesis, probably due to its functions in activating P protein and taking up the role of L protein in the non‐enzymatic reduction of Hox to Hred. Moreover, the presence of some monovalent and divalent metal ions can have either positive or negative effect on the rate of glycine synthesis, depending on their type and their concentration.