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2.
Nature ; 585(7824): 225-233, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32908268

RESUMO

Isoprene is the dominant non-methane organic compound emitted to the atmosphere1-3. It drives ozone and aerosol production, modulates atmospheric oxidation and interacts with the global nitrogen cycle4-8. Isoprene emissions are highly uncertain1,9, as is the nonlinear chemistry coupling isoprene and the hydroxyl radical, OH-its primary sink10-13. Here we present global isoprene measurements taken from space using the Cross-track Infrared Sounder. Together with observations of formaldehyde, an isoprene oxidation product, these measurements provide constraints on isoprene emissions and atmospheric oxidation. We find that the isoprene-formaldehyde relationships measured from space are broadly consistent with the current understanding of isoprene-OH chemistry, with no indication of missing OH recycling at low nitrogen oxide concentrations. We analyse these datasets over four global isoprene hotspots in relation to model predictions, and present a quantification of isoprene emissions based directly on satellite measurements of isoprene itself. A major discrepancy emerges over Amazonia, where current underestimates of natural nitrogen oxide emissions bias modelled OH and hence isoprene. Over southern Africa, we find that a prominent isoprene hotspot is missing from bottom-up predictions. A multi-year analysis sheds light on interannual isoprene variability, and suggests the influence of the El Niño/Southern Oscillation.


Assuntos
Atmosfera/química , Butadienos/análise , Butadienos/química , Mapeamento Geográfico , Hemiterpenos/análise , Hemiterpenos/química , Imagens de Satélites , África , Austrália , Brasil , Conjuntos de Dados como Assunto , El Niño Oscilação Sul , Formaldeído/química , Radical Hidroxila/análise , Radical Hidroxila/química , Ciclo do Nitrogênio , Óxidos de Nitrogênio/análise , Óxidos de Nitrogênio/química , Oxirredução , Estações do Ano , Sudeste dos Estados Unidos
3.
Sci Total Environ ; 738: 140357, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32806374

RESUMO

The wood panel industry requires the introduction of more environmental-friendly adhesives due to the strict current regulations on formaldehyde-based emissions. The purpose of this study was to environmentally analyse the production of four different bio-adhesives as alternatives to the most conventional fossil resins used in the production of wood panels. The bio-adhesives proposed for analysis derived from different available renewable biopolymers such as protein (soy) and lignin (Kraft and Organosolv), as well as tannin. The production systems were evaluated from a cradle-to-gate perspective using the Life Cycle Assessment methodology, with the aim of identifying critical parameters and comparing them with fossil substitutes. Inventory data of bio-adhesives were modelled at large scale from lab scale experiments and completed with literature reports. Our results showed that the soy-based and tannin based bio-adhesive had an overall better profile than fossil resins, identifying the production of polyacrylamide for the former, and the production of condensed tannin and glyoxal for the latter, as the main environmental hotspots. In contrast, further research is required on the use of lignins, specifically because of the electricity requirements in the lignin glyoxalation stage (a process required for the functionalization of lignin). Sensitivity analyses were conduced on these key parameters suggesting that there is room for improvement.This study provides useful information for researchers and policy-makers on where to focus their activities with the aim of making the future of bio-adhesives more technically and environmentally favourable.


Assuntos
Adesivos , Madeira , Formaldeído , Indústrias , Lignina
4.
Environ Pollut ; 265(Pt B): 115003, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806450

RESUMO

An indoor formaldehyde enriched environment was created by an automatic fumigation system with timing and concentration control. Selected hydroponic plant species were exposed in formaldehyde concentrations of 10 mg m-3, 50 mg m-3 and 100 mg m-3 respectively for 6 days with 10-h-treatment each day. Changes in morphological characteristics including leaf damage rate, leaf damage time and survival rate were monitored to evaluate morphological resistance to formaldehyde. Assessed physiological parameters were leaf chlorophyll content (Chl), leaf malondialdehyde content (MDA), activity of leaf formaldehyde dehydrogenase (FADH), leaf water soluble sugar content (WSS), and leaf proline content (Pro). Under formaldehyde suppression, reduction of Chl and increase of MDA and Pro were observed. Varying by species, FADH and WSS peaked at certain formaldehyde concentrations. A Principal Component Analysis (PCA) method was adopted to evaluate key factors in hydroponic plants' tolerance to formaldehyde. Among the 15 species selected, the best 5 performing species are Spathiphyllum floribundum, Alocasia cucullata, Davallia bullata, Syngonium podophyllum 'Pixie', and Schefflera octophylla. The study helps people to select the best ornamental plants for indoor air pollution control. The response of hydroponic plant species to formaldehyde was studied for eco-friendly indoor air pollution control.


Assuntos
Formaldeído , Plantas , Clorofila , Hidroponia , Folhas de Planta
5.
PLoS One ; 15(8): e0236104, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32776939

RESUMO

There is an increasing emphasis on effects-based monitoring to document responses associated with exposure to complex mixtures of chemicals, climate change, pathogens, parasites and other environmental stressors in fish populations. For decades aquatic monitoring programs have included the collection of tissues preserved for microscopic pathology. Consequently, formalin-fixed, paraffin-embedded (FFPE) tissue can be an important reservoir of nucleic acids as technologies emerge that utilize molecular endpoints. Despite the cross-linking effects of formalin, its impact on nucleic acid quality and concentration, amplification, and sequencing are not well described. While fresh-frozen tissue is optimal for working with nucleic acids, FFPE samples have been shown to be conducive for molecular studies. Laser capture microdissection (LCM) is one technology which allows for collection of specific regions or cell populations from fresh or preserved specimens with pathological alterations, pathogens, or parasites. In this study, smallmouth bass (Micropterus dolomieu) liver was preserved in three different fixatives, including 10% neutral buffered formalin (NBF), Z-Fix® (ZF), and PAXgene® (PG) for four time periods (24 hr, 48 hr, seven days, and 14 days). Controls consisted of pieces of liver preserved in RNALater® or 95% ethanol. Smallmouth bass were chosen as they are an economically important sportfish and have been utilized as indicators of exposure to endocrine disruptors and other environmental stressors. Small liver sections were cut out with laser microdissection and DNA and RNA were purified and analyzed for nucleic acid concentration and quality. Sanger sequencing and the NanoString nCounter® technology were used to assess the suitability of these samples in downstream molecular techniques. The results revealed that of the formalin fixatives, NBF samples fixed for 24 and 48 hr were superior to ZF samples for both Sanger sequencing and the Nanostring nCounter®. The non-formalin PAXgene® samples were equally successful and they showed greater stability in nucleic acid quality and concentration over longer fixation times. This study demonstrated that small quantities of preserved tissue from smallmouth bass can be utilized in downstream molecular techniques; however, future studies will need to optimize the methods presented here for different tissue types, fish species, and pathological conditions.


Assuntos
Bass/genética , DNA/efeitos dos fármacos , Monitoramento Ambiental/métodos , Fixadores/efeitos adversos , RNA/efeitos dos fármacos , Animais , Clivagem do DNA/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Formaldeído/efeitos adversos , Perfilação da Expressão Gênica/métodos , Fígado/efeitos dos fármacos , Fígado/patologia , Microdissecção , Desnaturação de Ácido Nucleico/efeitos dos fármacos , RNA/isolamento & purificação , Estabilidade de RNA/efeitos dos fármacos , Análise de Sequência de DNA , Fatores de Tempo , Fixação de Tecidos/métodos , West Virginia
6.
Nat Commun ; 11(1): 3803, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32732991

RESUMO

Microbial communities comprised of phototrophs and heterotrophs hold great promise for sustainable biotechnology. Successful application of these communities relies on the selection of appropriate partners. Here we construct four community metabolic models to guide strain selection, pairing phototrophic, sucrose-secreting Synechococcus elongatus with heterotrophic Escherichia coli K-12, Escherichia coli W, Yarrowia lipolytica, or Bacillus subtilis. Model simulations reveae metabolic exchanges that sustain the heterotrophs in minimal media devoid of any organic carbon source, pointing to S. elongatus-E. coli K-12 as the most active community. Experimental validation of flux predictions for this pair confirms metabolic interactions and potential production capabilities. Synthetic communities bypass member-specific metabolic bottlenecks (e.g. histidine- and transport-related reactions) and compensate for lethal genetic traits, achieving up to 27% recovery from lethal knockouts. The study provides a robust modelling framework for the rational design of synthetic communities with optimized growth sustainability using phototrophic partners.


Assuntos
Bacillus subtilis/metabolismo , Escherichia coli/metabolismo , Processos Heterotróficos/fisiologia , Processos Fototróficos/fisiologia , Synechococcus/metabolismo , Yarrowia/metabolismo , Aldeídos/metabolismo , Bacillus subtilis/genética , Reatores Biológicos/microbiologia , Escherichia coli/genética , Etanol/metabolismo , Formaldeído/metabolismo , Metanol/metabolismo , Microbiota/fisiologia , Modelos Biológicos , Ácido Succínico/metabolismo , Synechococcus/genética , Yarrowia/genética
7.
J Med Life ; 13(2): 225-228, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32742518

RESUMO

The high prevalence of periodontal diseases in workers with professional contact with unfavorable factors of the production environment is an unresolved problem of dentistry. This study aimed to investigate the harmful effects of formaldehyde on periodontal tissues in woodworkers who have long-term contact with formaldehyde in their professional activities. Sixty-nine men with occupational exposure to formaldehyde were examined to study the effect of formaldehyde on the human periodontal tissues, looking particularly at signs of the periodontal tissues' inflammatory process using a series of periodontal indices. The study results showed that the condition of periodontal tissues was statistically significantly worse in woodworkers who have long-term contact with formaldehyde in their professional activities. However, the hygiene status was not significantly different in the main group and the comparison group. Thus, we concluded that working under conditions of constant exposure to formaldehyde has a negative effect on the condition of periodontal tissues.


Assuntos
Formaldeído/efeitos adversos , Indústrias , Exposição Ocupacional/análise , Periodonto/efeitos dos fármacos , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Saúde Bucal , Prevalência , Adulto Jovem
8.
Sheng Li Xue Bao ; 72(4): 463-474, 2020 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-32820309

RESUMO

Formaldehyde is one of the simplest organic small molecules containing C, H and O elements in the early stage of earth's evolution; however, it has been found to be existed in every eukaryotic cell and participate in "one carbon metabolism". Recent studies have shown that formaldehyde may act as a signal molecule to regulate memory formation. After electrical stimulation or learning activity, the levels of formaldehyde in rat brains were increased instantly, and N-methyl-D-aspartate (NMDA) receptor was activated to promote the formation of long-term potentiation (LTP) or spatial memory. On the contrary, after reducing the levels of formaldehyde in the brains, NMDA receptor could not be activated, which was accompanied by the deficits in both LTP and memory. Moreover, in the brains of normal aged rats and APP/PS1 transgenic mice, the concentrations of formaldehyde were abnormally increased, which directly inhibited NMDA receptor activity and impaired spatial memory. This article reviewed the physiological and pathophysiological functions of endogenous formaldehyde in learning and memory.


Assuntos
Potenciação de Longa Duração , Memória , Animais , Formaldeído , Hipocampo , Aprendizagem em Labirinto , Transtornos da Memória , Camundongos , Ratos , Receptores de N-Metil-D-Aspartato
9.
Nat Protoc ; 15(9): 2956-2979, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32737464

RESUMO

Bottom-up mass spectrometry-based proteomics relies on protein digestion and peptide purification. The application of such methods to broadly available clinical samples such as formalin-fixed and paraffin-embedded (FFPE) tissues requires reversal of chemical crosslinking and the removal of reagents that are incompatible with mass spectrometry. Here, we describe in detail a protocol that combines tissue disruption by ultrasonication, heat-induced antigen retrieval and two alternative methods for efficient detergent removal to enable quantitative proteomic analysis of limited amounts of FFPE material. To show the applicability of our approach, we used hepatocellular carcinoma (HCC) as a model system. By combining the described protocol with laser-capture microdissection, we were able to quantify the intra-tumor heterogeneity of a tumor specimen on the proteome level using a single slide with tissue of 10-µm thickness. We also demonstrate broader applicability to other tissues, including human gallbladder and heart. The procedure described in this protocol can be completed within 8 d.


Assuntos
Formaldeído , Espectrometria de Massas , Inclusão em Parafina , Proteômica/métodos , Fixação de Tecidos , Carcinoma Hepatocelular/patologia , Humanos , Neoplasias Hepáticas/patologia
10.
J Infect Dis ; 222(9): 1462-1467, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32798217

RESUMO

The scientific community has responded to the coronavirus disease 2019 (COVID-19) pandemic by rapidly undertaking research to find effective strategies to reduce the burden of this disease. Encouragingly, researchers from a diverse array of fields are collectively working towards this goal. Research with infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is undertaken in high-containment laboratories; however, it is often desirable to work with samples at lower-containment levels. To facilitate the transfer of infectious samples from high-containment laboratories, we have tested methods commonly used to inactivate virus and prepare the sample for additional experiments. Incubation at 80°C, a range of detergents, Trizol reagents, and UV energies were successful at inactivating a high titer of SARS-CoV-2. Methanol and paraformaldehyde incubation of infected cells also inactivated the virus. These protocols can provide a framework for in-house inactivation of SARS-CoV-2 in other laboratories, ensuring the safe use of samples in lower-containment levels.


Assuntos
Betacoronavirus/crescimento & desenvolvimento , Inativação de Vírus , Animais , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/efeitos da radiação , Bioensaio , Pesquisa Biomédica , Chlorocebus aethiops , Detergentes , Formaldeído , Guanidinas , Temperatura Alta , Metanol , Fenóis , Polímeros , Raios Ultravioleta , Células Vero , Ensaio de Placa Viral
11.
Sci Total Environ ; 745: 140875, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-32758742

RESUMO

Flocculants and coagulants market is expected to grow in a Compound Annual Growth Rate (CAGR) of 5.9% between 2017 and 2022. The development of non-pollutant coagulants/flocculants aiming to replace conventional ones, usually toxic, has been extensively studied and one alternative is the possibility of obtaining tannin-based flocculants, compounds present in many plants and easily extracted. However, in order to use tannins as flocculants, their cationization is necessary, which is normally accomplished by Mannich reaction that requires formaldehyde addition, a toxic compound. In order to fill a gap in the literature, regarding coagulants/flocculants synthesis through green procedures, this paper aims to synthesize a flocculant from tannins with no use of formaldehyde, and optimize this synthesis through a Central Composite Rotatable Design (CCRD). The optimization variables were ammonium hydroxide (NH4OH) to tannin ratio, in the range of 1:1 to 5:1, and reaction time, in the range of 1 to 4 h The evaluation of the synthesized flocculant samples was accomplished by jar tests using a simulated effluent containing humic acid and the effect of reactant ratio and reaction time used in the synthesis was assessed. The flocculant synthesis methodology proposed on this study showed excellent results regarding turbidity and color removal, since 100% of turbidity removal and 89.9% of color removal were achieved. This novel tannin-based flocculant synthesis methodology is a promising technology to replace conventional coagulants/flocculants, once it is environmentally friendly.


Assuntos
Acacia , Purificação da Água , Floculação , Formaldeído , Taninos
12.
Chemosphere ; 260: 127660, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758783

RESUMO

The occurrence and the fate of 18 ozonation by-products (OBPs) (17 different aldehydes and bromate) were studied over one year in two Canadian drinking water systems. This is the first and only study reporting the occurrence of all these non-halogenated aldehydes (NON-HALs) and haloacetaldehydes (HALs) simultaneously, based on the multi-point monitoring of water in full-scale conditions from source to distribution network. In general, the application of both post-ozonation and liquid chlorine contributed to the formation of OBPs (aldehydes and bromate). NON-HALs were present in higher concentrations than HALs. Formaldehyde, acetaldehyde, glyoxal and methylglyoxal were the most common forms of NON-HALs in the two water systems that were studied. Chloral hydrate (CH), the hydrated form of trichloroacetaldehyde, was the most dominant HAL observed. The nature of the organic matter and the water temperature proved to be important parameters for explaining the variability of aldehydes. Summer and autumn (warm seasons) were more favorable for the formation of chloral hydrate and bromate. The highest concentrations of NON-HALs were observed in spring.


Assuntos
Desinfecção , Água Potável , Poluentes Químicos da Água/análise , Purificação da Água , Acetaldeído/análise , Aldeídos , Bromatos , Canadá , Hidrato de Cloral/análogos & derivados , Cloro , Formaldeído , Ozônio
13.
Klin Monbl Augenheilkd ; 237(7): 860-866, 2020 Jul.
Artigo em Inglês, Alemão | MEDLINE | ID: mdl-32659839

RESUMO

The high-throughput method of "Next Generation Sequencing" (NGS) allows cost-effective decoding of the nucleotide sequences of millions of RNA molecules in a sample. This makes it possible to determine the number of distinct RNA molecules in tissues or cells and to use these data to draw conclusions. The entirety of RNAs, in particular mRNAs (messenger RNAs) as potential precursors of proteins, provides a comprehensive insight into the functional state of the cells and tissues under investigation. In addition to cell cultures or unfixed tissue, formalin-fixed and paraffin-embedded (FFPE) tissue can also be analysed for this purpose using specific methods. In this overview, the methodological strategy and its application to the field of ophthalmic histopathology are presented.


Assuntos
Formaldeído , Sequenciamento de Nucleotídeos em Larga Escala , Sequência de Bases , Humanos , Oftalmologia , Inclusão em Parafina , Patologia , Análise de Sequência de RNA , Manejo de Espécimes
14.
Environ Sci Pollut Res Int ; 27(31): 39180-39185, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32642895

RESUMO

For the first time, the National Health and Nutrition Examination Survey (NHANES) released data on hemoglobin adducts of formaldehyde (HCHO) in public domain for US children aged 6-11 years, adolescents aged 12-19 years, and adults aged > = 20 years for 2015-2016. This study was undertaken to evaluate the associations between concentrations of HCHO in whole blood and smoking, exposure to environmental tobacco smoke (ETS), and self-reported diagnoses of cancers and asthma. Adult smokers were found to have higher adjusted concentrations of HCHO than nonsmokers (127.7 vs. 125.1 pmol/g Hb, p = 0.02). Exposure to ETS was not found to affect the adjusted concentrations of HCHO. No associations were observed between HCHO concentrations and self-reported diagnosis of "ever" cancer as well as self-reported presence of asthma at the time of participation in NHANES. HCHO concentrations were not found to differ across genders and racial/ethnic groups for children and adolescents. Among adults, non-Hispanic blacks (120.0 pmol/g Hb) had lower adjusted concentrations (p < = 0.01) of HCHO than non-Hispanic whites (128.8 pmol/g Hb), Mexican Americans (129.4 pmol/g Hb), other Hispanics (130.3 pmol/g Hb), and non-Hispanic Asians (127.9 pmol/g Hb). In conclusion, self-reported diagnoses of cancer and asthma were not found to be associated with observed concentrations of HCHO in whole blood.


Assuntos
Asma , Neoplasias , Poluição por Fumaça de Tabaco , Adolescente , Adulto , Criança , Feminino , Formaldeído , Humanos , Masculino , Inquéritos Nutricionais , Autorrelato , Fumar , Adulto Jovem
16.
Sci Total Environ ; 738: 139803, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32563789

RESUMO

Time-series measurements of methylmercury (MeHg) concentrations in short-lived planktic animals, such as copepods, could allow for an evaluation of mercury (Hg) inputs and transferability to organisms in marine environments. If reliable, MeHg measurements in formalin-preserved marine animals could offer insights into past environmental MeHg levels. In the present study, we examined whether the amount of MeHg changed over time in formalin-preserved copepods for two species, Acartia tonsa, and Temora longicornis. Over a 51 (A. tonsa) and 7 (T. longicornis) week incubation, we found significant changes in MeHg content in both copepods, while the timing of these changes differed between species. Furthermore, we investigated the mechanism behind these temporal changes through a separate incubation experiment of formalin spiked with two levels of organic matter (OM), and stable-isotope-enriched Hg tracers. We found that the methylation of an inorganic 199Hg tracer was significantly higher in OM-enriched solutions in comparison to a control seawater-formalin solution. Our results suggest that formalin-preserved copepods are not fit for studies of past trends due to ongoing and unpredictable abiotic transformations of Hg in chemically preserved animal tissue.


Assuntos
Mercúrio/análise , Compostos de Metilmercúrio , Poluentes Químicos da Água/análise , Animais , Bioacumulação , Monitoramento Ambiental , Cadeia Alimentar , Formaldeído , Zooplâncton
17.
J Chromatogr A ; 1623: 461192, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505285

RESUMO

An imidazolium ionic-liquid-modified phenolic resin (ILPR) was synthesized using 3-aminophenol as a functional monomer, glyoxylic acid as a green cross-linker, and polyethylene glycol 6000 as a porogen. The obtained ILPR showed better extraction of benzoylurea plant hormones thidiazuron and forchlorfenuron than the unmodified phenolic resin because the imidazolium IL provides more interaction modes with the analytes. ILPR, as a tailored adsorbent for solid-phase extraction, was coupled with high-performance liquid chromatography (ILPR‒SPE‒HPLC) for the simultaneous determination of thidiazuron and forchlorfenuron in cucumbers. Good linearity of the ILPR‒SPE‒HPLC method was obtained, ranging from 0.0100 to 5.00 µg g-1 with a correlation coefficient (r) ≥ 0.9999. The recoveries of spiked samples ranged from 91.4% to 100.7% with a relative standard deviation of ≤ 6.0%.


Assuntos
Cucumis sativus/química , Formaldeído/química , Imidazóis/química , Líquidos Iônicos/química , Fenóis/química , Compostos de Fenilureia/isolamento & purificação , Polímeros/química , Piridinas/isolamento & purificação , Extração em Fase Sólida/métodos , Tiadiazóis/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Formaldeído/síntese química , Líquidos Iônicos/síntese química , Cinética , Fenóis/síntese química , Polímeros/síntese química , Reprodutibilidade dos Testes
18.
Nat Commun ; 11(1): 3128, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32561732

RESUMO

Whole-cell cross-linking coupled to mass spectrometry is one of the few tools that can probe protein-protein interactions in intact cells. A very attractive reagent for this purpose is formaldehyde, a small molecule which is known to rapidly penetrate into all cellular compartments and to preserve the protein structure. In light of these benefits, it is surprising that identification of formaldehyde cross-links by mass spectrometry has so far been unsuccessful. Here we report mass spectrometry data that reveal formaldehyde cross-links to be the dimerization product of two formaldehyde-induced amino acid modifications. By integrating the revised mechanism into a customized search algorithm, we identify hundreds of cross-links from in situ formaldehyde fixation of human cells. Interestingly, many of the cross-links could not be mapped onto known atomic structures, and thus provide new structural insights. These findings enhance the use of formaldehyde cross-linking and mass spectrometry for structural studies.


Assuntos
Reagentes para Ligações Cruzadas/química , Formaldeído/química , Mapeamento de Interação de Proteínas/métodos , Proteínas/química , Aminoácidos/química , Linhagem Celular Tumoral , Humanos , Espectrometria de Massas , Simulação de Acoplamento Molecular , Proteínas/metabolismo
19.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 942-948, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32567277

RESUMO

It is of great significance to use biosynthesis to transform the inorganic substance formaldehyde into organic sugars. Most important in this process was to find a suitable catalyst combination to achieve the dimerization of formaldehyde. In a recent report, an engineered glycolaldehyde synthase was reported to catalyze this reaction. It could be combined with engineered D-fructose-6-phosphate aldolase, a "one-pot enzyme" method, to synthesize L-xylose using formaldehyde and the conversion rate could reach up to 64%. This process also provides a reference for the synthesis of other sugars. With the increasing consumption of non-renewable resources, it was of great significance to convert formaldehyde into sugar by biosynthesis.


Assuntos
Formaldeído , Xilose , Biocatálise , Formaldeído/química , Frutose-Bifosfato Aldolase/metabolismo , Xilose/síntese química
20.
Environ Pollut ; 264: 114819, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32559879

RESUMO

Pyrolysis bio-oil was used to partially substitute for phenol in reacting with formaldehyde for the production of bio-oil phenol formaldehyde plywood (BPFP) panels, with the phenol substitution ratio being 20%, 40%, or 60%. Emissions of formaldehyde and volatile organic compounds (VOCs) from the BPFP panels were studied using solid-phase micro-extraction (SPME) followed by headspace gas chromatography/mass spectrometry (GC/MS), and were compared to those from the phenol formaldehyde plywood (PFP) panels. The sources for VOCs were analyzed, and the health risks associated with the BPFP were examined. Results showed that at 80 °C: (1) Formaldehyde emissions from the BPFP panels were increased to about 4 times that of PFP; (2) VOCs emissions were significantly reduced by up to 84.9% mainly due to the greatly reduced phenol emissions, although the total number of VOCs was increased from 20 to 35; (3) BPFP presents greatly increased carcinogenic and non-carcinogenic health risks because of its much stronger emissions of formaldehyde, N,N-dimethylformamide, benzofuran, furfural, and many chemicals from the bio-oil. It is highly advisable that the health risks are properly taken care of before the wide application of BPFP, or similar bio-oil based engineered wood products.


Assuntos
Compostos Orgânicos Voláteis , Formaldeído , Fenóis , Óleos Vegetais , Polifenóis
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