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1.
Environ Sci Pollut Res Int ; 27(20): 25553-25562, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32350836

RESUMO

Water treatment sludge (WTS) is abundantly produced in the world; the waste contributes to the environmental problems. Therefore, for WTS utilization, aluminum leaching was employed using hydrochloric acid in this study. Al leaching efficiency increased from 72% to 80% as hydrochloric acid concentration increased from 1 to 4 M. Decreasing the particle size and increasing the temperature increased Al leaching efficiency. The proposed kinetic model revealed that the rate-controlling step followed a series of two leaching mechanisms: initially controlled by product-layer diffusion and then by a chemically controlled reaction. For instance, at 70 °C, the initial stage is well fitted by product-layer diffusion (R2 = 0.87) compared to R2 = 0.60 for chemical reaction; while for the second stage, R2 = 0.95 was observed via chemical reaction compared to R2 = 0.74 for product-layer diffusion. The activation energies in these two stages were 9.58 kJ/mol and 10.73 kJ/mol, respectively. The proposed model was well validated by using data from literature and thus will be useful for other applications of leaching and extraction processes.


Assuntos
Alumínio , Purificação da Água , Ácido Clorídrico , Cinética , Esgotos
2.
Environ Sci Pollut Res Int ; 27(21): 26221-26238, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32361968

RESUMO

Soil salinity and acidity are some of the major causes of land degradation and have a negative impact on agricultural productivity. Assessing soil quality (SQ) of soils affected by soil salinity and acidity is required for their sustainable utilization for agricultural production. The aim of the present study was to evaluate the SQ of the salt-affected acid soils of the Indian West Coastal region using the additive and weighted soil quality indices (SQIs). The SQIs were developed using a total dataset (TDS) and a minimum dataset (MDS). The TDS comprised of 15 different soil properties as electrical conductivity (EC), pH, bulk density, soil available nitrogen (N), phosphorus (P), potassium (K), sulfur (S), boron (B), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) and exchangeable calcium (Ca), magnesium (Mg), and sodium (Na) measured on 300 soil samples (depth 0-0.15 m). Based on principal component analysis and correlation analysis, an MDS with soil properties like soil pH, EC, Na, Cu, Mn, and BD was formed. Using two approaches (additive and weighted), two datasets (TDS and MDS), and two scoring methods (linear and non-linear), eight SQIs were developed. The MDS-based linear weighted and non-linear weighted SQI found suitable to evaluate SQ of salt-affected acid soils and SQI had a significant and negative correlation of - 0.83 and - 0.70 (p < 0.01) with EC, respectively. Thus, it is clear that the SQ considerably reduces with an increase in soil salinity. The performance of the MDS-based SQIs was better than the TDS to discriminate different soil salinity classes. The agreement between the linear and non-linear scoring method of SQI had a linear relationship with a coefficient of determination (R2) of 0.91-0.96. Thus, assessing the SQ of salt-affected acid soils using MDS, linear scoring, and weighted approach of the soil quality indexing could save the time and cost involved.


Assuntos
Ácido Clorídrico , Solo , Agricultura , Índia , Salinidade
3.
Bioresour Technol ; 309: 123390, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32325379

RESUMO

The effectiveness of the modification of wheat straw biochar using FeCl3 and HCl, alone or combined, on ammonium adsorption was evaluated using kinetic and isotherm models. The adsorption mechanisms were studied by comparative analysis of the surface properties of the biochars before and after ammonium adsorption. The results indicate that the modification methods enhanced the ammonium adsorption capacity by at least 14%, due to the increased OH and OCO functional groups and specific surface area, and increased Fe3+/Fe2+ redox coupling serving as an electron shuttle. It can be concluded that chemical modification of wheat straw biochars using FeCl3 and HCl increased the effectiveness of biochars for the treatment of ammonium-contaminated wastewater.


Assuntos
Compostos de Amônio , Adsorção , Carvão Vegetal , Ácido Clorídrico , Ferro
5.
Chemosphere ; 251: 126356, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32146186

RESUMO

EPA 3051A and Aqua Regia (AR) are widely adopted by global environmental agencies to assess soil quality in relation to potentially harmful elements (PHE). However, previous study has shown the formation of large amounts of short-range order materials (SRO) in the residues of these extractions. Residues obtained from the 3051A and AR were recovered from filter papers. To characterize the SRO in these residues, sequential extractions were performed with 0.2 mol L-1 ammonium oxalate (AO) and 0.5 mol L-1 NaOH. On average (n = 15), the 3051A and AR residues contained 37% and 60% of SRO, respectively. The largest amounts of SRO formed in the AR residue was in sample 5 (99% of SRO). The main component of the SRO was Al2O3-AO, Fe2O3-AO and SiO2-NaOH. The formation of SRO and PHE resorption levels were random and highly dependent on the mineralogy of the soil clay fraction. Soils rich in smectites, which are more common in temperate regions, formed larger amounts of SRO. The association of Pb with the SRO was more pronounced in the 3051A residue than in the AR residue. If SRO was not extracted after 3051A, in sample 7, for example, 595 mg kg-1 of Pb (10.2%) would have not been accounted. The maximum PHE resorptions in SRO were (%): Pb - 10; Cu - 470; Ba - 280; As - 21. The underestimation of PHE contents due to resorption mechanisms may lead an environmental agency to certify the use of an area contaminated with PHE.


Assuntos
Monitoramento Ambiental/métodos , Certificação , Ácido Clorídrico , Metais Pesados/análise , Ácido Nítrico , Dióxido de Silício , Solo/química , Poluentes do Solo/análise
6.
Arch Oral Biol ; 112: 104686, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32112967

RESUMO

OBJECTIVE: Aim of this in vitro study was to investigate erosive tooth loss in dependence of the enamel surface structure and presence of an acquired pellicle. METHODS: Enamel specimens from 19 bovine incisors (4 specimens/incisor) were allocated to four experimental groups (n = 19). The surfaces of half of the specimens were polished (two groups), while the other half was left native (two groups). Specimens of one polished and one native group were placed in pooled human saliva (30 min) for the formation of an acquired pellicle. Thereafter, all specimens were demineralized by superfusion with hydrochloric acid (17 min, pH 2.3) with collection of the superfluent. Erosive substance loss was determined by measuring the dissolved calcium content using a colorimetric assay with Arsenazo III reagent. Differences in erosive substance loss were statistically analyzed with respect to enamel surface and pellicle. A linear mixed effects model was fitted to the data and pairwise differences between groups were evaluated (significance level α= 0.05). RESULTS: Enamel surface structure (p < 0.001) and presence of pellicle (p = 0.01) had a significant effect on erosive substance loss. Polished surfaces with pellicle showed the lowest cumulative calcium release [nmol Ca/mm2] (means ± standard deviation: 48+/-5), followed by polished specimens without (51+/-9) and native specimens with pellicle (54+/-10). No significant differences were found between these groups. Highest cumulative calcium release was found for native specimens without pellicle (61+/-9; p < 0.05). CONCLUSIONS: Both enamel surface structure and the acquired pellicle are important determinants of the susceptibility to erosive tooth loss.


Assuntos
Esmalte Dentário/química , Película Dentária/química , Erosão Dentária , Animais , Bovinos , Ácido Cítrico , Solubilidade do Esmalte Dentário , Humanos , Ácido Clorídrico , Saliva
7.
Chem Biol Interact ; 321: 108964, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-32006539

RESUMO

Lupeol (1) was isolated from hexane branch extract of Maytenus salicifolia and the Lupeol stearate (2), Lupeol palmitate (3), Lupeol myristate (4), Lupeol laurate (5) and Lupeol caprylate (6) were obtained reacting 1 with an adequate carboxylic acid. Swiss mice were treated with vehicle, carbenoxolone or Lupeol esters before administration of ethanol/HCl or indomethacin. Additionally, the involvement of nitric oxide (NO), sulfhydryl compounds (NP-SH), α-2 adrenergic receptors (α2-AR) and prostaglandins (PGE) in antiulcer effects was investigated using appropriate inhibitors or antagonist. Oxidative and inflammatory parameters were measured after euthanasia and anti-secretory effects was evaluated in pylorus-ligated rats. Ethanol/HCl ulcerated the gastric mucosa by 64.45 ± 6.58 mm2, which the oral treatment with 1, 4 and 6 (10 mg/kg), and 3 and 5 (30 mg/kg) reduced the lesion area. Interestingly, 2 reduced the gastric ulcer by oral route in a potent and dose-dependent manner (ED50 = 0.40 mg/kg), which was accompanied by the increase in reduced glutathione levels and by the reduction of lipids peroxidation and myeloperoxidase and superoxide dismutase activities. Moreover, 2 (0.1 mg/kg) also prevented the ulcerogenesis by intraperitoneal route. The participation of NO, NP-SH, α2-AR and PGE in 2-mediated gastroprotection was confirmed. In indomethacin-induced ulcer, 2 (1 mg/kg, p.o) also reduced the ulcer area and increased the PGE2 levels. However, 2 did not alter the gastric acid secretion. Therefore, these findings indicate that the obtention of 2 potentiated the antiulcer activity of 1 and that this compound can elicit gastroprotective action due a diversified mode of action.


Assuntos
Antiulcerosos/farmacologia , Triterpenos Pentacíclicos/farmacologia , Úlcera Gástrica/prevenção & controle , Animais , Antiulcerosos/administração & dosagem , Antiulcerosos/química , Modelos Animais de Doenças , Esterificação , Etanol/toxicidade , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Ácido Clorídrico/toxicidade , Indometacina/toxicidade , Camundongos , NG-Nitroarginina Metil Éster/metabolismo , Óxido Nítrico/metabolismo , Triterpenos Pentacíclicos/administração & dosagem , Triterpenos Pentacíclicos/química , Ratos , Ratos Wistar , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/metabolismo , Relação Estrutura-Atividade
8.
PLoS One ; 15(2): e0228595, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027708

RESUMO

Acid orange 74 (AO74) is a chromium-complex monoazo acid dye widely used in the textile industry. Due to being highly toxic and non-biodegradable, it must be removed from polluted water to protect the health of people and the environment. The aim of this study was two-fold: to evaluate the biosorption of AO74 from an aqueous solution by utilizing HCl-pretreated Lemna sp. (HPL), and to examine dye desorption from the plant material. The maximum capacity of AO74 biosorption (64.24 mg g-1) was reached after 4 h at the most adequate pH, which was 2. The biosorption capacity decreased 25% (to 48.18 mg g-1) during the second biosorption/desorption cycle and remained essentially unchanged during the third cycle. The pseudo-second-order kinetics model concurred well with the experimental results of assays involving various levels of pH in the eluent solution and distinct initial concentrations of AO74. NaOH (0.01 M) was the best eluent solution. The Toth isotherm model best described AO74 biosorption equilibrium data. FTIR analysis confirmed the crucial role of HPL proteins in AO74 biosorption. SEM-EDX and CLSM techniques verified the effective biosorption/desorption of the dye during the three cycles. Therefore, HPL has potential for the removal of AO74 dye from wastewaters.


Assuntos
Araceae/metabolismo , Compostos Azo/isolamento & purificação , Biodegradação Ambiental , Corantes/isolamento & purificação , Adsorção , Compostos Azo/toxicidade , Corantes/toxicidade , Ácido Clorídrico , Concentração de Íons de Hidrogênio , Cinética , Indústria Têxtil , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/toxicidade
9.
Food Chem ; 315: 126288, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32032833

RESUMO

ß-Carotene was encapsulated in the Pickering emulsions stabilized by chitosan hydrochloride - carboxymethyl starch (CHC-CMS) nanogels. During ultraviolet radiation and storage, the retention of ß-carotene in Pickering emulsions was higher than that of other formulations, such as Tween 80 stabilized emulsions (TEs) and bulk oil. The Pickering emulsions were found to be stable during thermal treatment. Meanwhile, lipid oxidation was delayed in Pickering emulsions compared to TEs and bulk oil. The vitro digestion results suggested that the free fatty acids (FFA) released were below 30% for all Pickering emulsions, which indicated that a physical barrier was formed by CHC-CMS nanogels to restrain the lipid hydrolysis. The bioaccessibility of ß-carotene in Pickering emulsions was higher than that in bulk oil. This research helped establish a connection between the physicochemical properties of CHC-CMS stabilized Pickering emulsions with their applications in the protection effect and oral delivery of bioactive compounds.


Assuntos
Quitosana/química , beta Caroteno/química , Quitosana/análogos & derivados , Emulsões/química , Ácido Clorídrico/química , Hidrólise , Lipídeos/química , Nanogéis/química , Oxirredução , Tamanho da Partícula , Amido/análogos & derivados , Raios Ultravioleta
10.
Int J Food Microbiol ; 322: 108562, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32109682

RESUMO

Shiga toxin-producing Escherichia coli (STEC) in sprouts have caused large scale outbreaks in the past involving severe illness. The combination of this very diverse pathogen and a food matrix with high numbers of background microbiota poses a particular challenge for detection and isolation. An acid treatment of the enrichment before plating on agar has been shown to improve the recovery of STEC from sprouts. After enrichment in buffered peptone water (BPW) at 37 °C we applied an acid treatment, followed by plating on tryptone bile x-glucuronide (TBX) agar (acid bile method). An inter-laboratory study was organized with 21 laboratories taking part to evaluate the performance parameters and applicability of the acid bile method. A sample set of six sprout samples was prepared consisting of two uninoculated samples and four spiked samples, each containing one of two STEC strains at one of two concentrations (low and high). Analyzing a set of six samples at the National Reference Laboratory (NRL E. coli), we determined the relative abundance of STEC without, after acid-, after bile- and after acid-bile treatment using real-time PCR. The participating laboratories successfully applied the acid bile method and were better able to detect (sensitivity 92.9% vs. 70.0%) and isolate (sensitivity 87.5% vs. 31.3%) STEC from positive samples using the acid bile method compared to non-acid methods. The relative limit of detection (RLOD) after isolation using the acid bile method (vs. non-acid method) was <1 for both STEC strains used, BfR-EC-14434 O133:H25 (0.146) and BfR-EC-16015 O26:H11 (0.073). A collection of STEC (n = 71) of diverse type and characteristics was assessed for their resistance towards the acid bile treatment selection. The majority (n = 65) of STEC strains could be recovered after acid treatment on TBX plates. However, a few strains (n = 6), among them clinical isolates were (partly) sensitive. These results suggest that an acid bile method is a rapid and reasonable approach to improve the recovery of STEC from sprouts when used in combination with methods targeting other selection markers.


Assuntos
Ácidos e Sais Biliares/metabolismo , Microbiologia de Alimentos/métodos , Ácido Clorídrico/metabolismo , Escherichia coli Shiga Toxigênica/isolamento & purificação , Verduras/microbiologia , Ágar , Animais , Meios de Cultura/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Plântula/microbiologia , Escherichia coli Shiga Toxigênica/metabolismo
11.
Am J Physiol Gastrointest Liver Physiol ; 318(4): G613-G623, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32068440

RESUMO

Esophageal injury from acid exposure related to gastroesophageal reflux disease is a common problem and a risk factor for development of Barrett's esophagus and esophageal adenocarcinoma. Our previous work highlights the benefits of using porcine esophagus to study human esophageal disease because of the similarities between porcine and human esophagus. In particular, esophageal submucosal glands (ESMGs) are present in human esophagus and proximal porcine esophagus but not in rodent esophagus. Although CFTR is expressed in the ducts of ESMGs, very little is known about CFTR and alternate anion channels, including ClC-2, in the setting of acid-related esophageal injury. After finding evidence of CFTR and ClC-2 in the basal layers of the squamous epithelium, and in the ducts of the ESMGs, we developed an ex vivo porcine model of esophageal acid injury. In this model, esophageal tissue was placed in Ussing chambers to determine the effect of pretreatment with the ClC-2 agonist lubiprostone on tissue damage related to acid exposure. Pretreatment with lubiprostone significantly reduced the level of acid injury and significantly augmented the recovery of the injured tissue (P < 0.05). Evaluation of the interepithelial tight junctions showed well-defined membrane localization of occludin in lubiprostone-treated injured tissues. Pretreatment of tissues with the Na+-K+-2Cl- cotransporter inhibitor bumetanide blocked lubiprostone-induced increases in short-circuit current and inhibited the reparative effect of lubiprostone. Furthermore, inhibition of ClC-2 with ZnCl2 blocked the effects of lubiprostone. We conclude that ClC-2 contributes to esophageal protection from acid exposure, potentially offering a new therapeutic target.NEW & NOTEWORTHY This research is the first to describe the presence of anion channels ClC-2 and CFTR localized to the basal epithelia of porcine esophageal mucosa and the esophageal submucosal glands. In the setting of ex vivo acid exposure, the ClC-2 agonist lubiprostone reduced acid-related injury and enhanced recovery of the epithelial barrier. This work may ultimately provide an alternate mechanism for treating gastroesophageal reflux disease.


Assuntos
Mucosa Esofágica/efeitos dos fármacos , Lubiprostona/farmacologia , 16,16-Dimetilprostaglandina E2/farmacologia , Animais , Bumetanida/farmacologia , Agonistas dos Canais de Cloreto/farmacologia , Canais de Cloreto/genética , Canais de Cloreto/metabolismo , Cloretos/farmacologia , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Relação Dose-Resposta a Droga , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Ácido Clorídrico/farmacologia , Masculino , Ocludina/metabolismo , Suínos , Fatores de Tempo , Compostos de Zinco/farmacologia
12.
J Environ Manage ; 260: 110001, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941640

RESUMO

An acid-recovering nanofiltration (NF) membrane with both acid resistance and selective acid permeability was fabricated via a water-based coating process for the recovery of hydrochloric acid. To achieve this, a thermally cross-linked branched-polyethyleneimine (b-PEI) layer was introduced to a loose polyethersulfone NF membrane by dip-coating of b-PEI and an epoxy linker and heat treatment in a sealed oven with a high-humidity atmosphere. The resulting membrane displayed a positive surface charge with a zeta potential, and exhibited a rejection performance order of MgCl2> MgSO4> NaCl > Na2SO4 characteristic of positive-charge-separation membranes. Mg rejection and Cl permeation experiments showed that the selective permeation of hydrochloric acid was achieved with Mg rejection above 95% and Cl permeation above 70%, and this allowed the acid to be recovered by obtaining permeate at the same pH as the feed. Moreover, the NF membrane maintained selective separation performance and flow rate for a month.


Assuntos
Filtração , Poluentes Químicos da Água , Ácido Clorídrico , Membranas Artificiais , Permeabilidade
13.
Am J Clin Pathol ; 153(2): 258-265, 2020 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-31603186

RESUMO

OBJECTIVES: To evaluate the effects of decalcifying agents on programmed cell death ligand 1 (PD-L1) immunohistochemistry (IHC). METHODS: Fragments of 10 placentas (high PD-L1 expressor) and 10 lungs (lower PD-L1 expressor) were formalin-fixed and subjected to four decalcifying solutions (EDTA, formic acid/MasterCal IM Plus [FA/MC], 12% HCl, and Decal STAT/23% HCl) for 1, 2, 6, or 24 hours. H&E staining and PD-L1 using IHC 22C3 pharmDx were performed, and PD-L1 staining was assessed. RESULTS: Minimal to no change in staining intensity or proportion of stained cells was seen with EDTA or FA/MC at all decalcifying durations. Both HCl-based decalcifiers demonstrated a progressive decrease in percentage of positive cells and staining intensity with longer decalcifying duration, particularly with Decal STAT. CONCLUSIONS: EDTA and FA/MC have little effect on PD-L1 expression. 12% HCl causes a progressive decline in staining. Decal STAT dramatically reduced staining with all treatment durations, especially at 24 hours.


Assuntos
Antígeno B7-H1/análise , Quelantes de Cálcio/farmacologia , Ácido Edético/farmacologia , Ácido Clorídrico/farmacologia , Feminino , Formiatos/farmacologia , Humanos , Imuno-Histoquímica , Pulmão/química , Placenta/química , Gravidez , Estudos Prospectivos
14.
J Sci Food Agric ; 100(3): 1072-1079, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31650550

RESUMO

BACKGROUND: Acid-induced hydrolysis of proteins has been used to improve the solubility and functional properties of various proteins, and could be a promising tool to facilitate the use of currently underutilized insoluble microalgae protein-rich fractions in food applications. However, the results of a prior study showed an unusual resistance of an insoluble microalgae protein-rich fraction to acid hydrolysis at room temperature. RESULTS: In the present study, the insoluble protein-rich fraction extracted from microalgae Chlorella prothothecoides was treated with 0.5 mol L-1 hydrochloric acid at 25, 45, 65 or 85 °C for 0-4 h. The results showed that hydrolysis of the fraction at 85 °C for 4 h led to decreases in the amount of insoluble protein-rich aggregates and the formation of fragments with a lower molecular weight, as well as an increase in protein solubility by approximately 40%. Nevertheless, some aggregated insoluble protein-rich particles remained, even after hydrolysis at 85 °C for 4 h. CONCLUSION: The higher temperature improved the efficiency of the acid hydrolysis of the insoluble protein fraction from microalgae Chlorella prothothecoides, which is highly acid-resistant. Overall, an erosion-based mechanism was suggested for the acid hydrolysis of insoluble microalgae protein fraction. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Chlorella/química , Proteínas/química , Fracionamento Químico , Temperatura Alta , Ácido Clorídrico/química , Hidrólise , Microalgas/química , Peso Molecular , Proteínas/isolamento & purificação , Solubilidade
15.
J Agric Food Chem ; 68(10): 2906-2916, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-31267749

RESUMO

In this study, we optimized the HCl-butanol-acetone-iron (HBAI) assay for the analysis of B-linked procyanidin (PC) and prodelphinidin (PD) condensed tannins (CTs) by direct analysis of whole tissue and sequential analysis of acetone-water extracts and insoluble residues prepared from forage, woody plant, food, and food byproduct samples. Yields of anthocyanidins (cyanidin and delphinidin) were optimized by heating ≤0.25 mg mL-1 CT standards, 1 mg mL-1 tissue, or 1-2 mg mL-1 acetone-water fractioned tissue for 3 h at 70 °C in medium containing 5% concentrated HCl, 6.7% total water, 50% acetone, 42% n-butanol, and 0.15% ammonium iron(III) sulfate dodecahydrate. Accurate quantitation required CT standards of known purity sourced from the same tissue being analyzed. Both analysis methods provided comparable estimates of total CTs for most PD-rich samples, but only the sequential method gave good recovery and accurate estimates of CTs in most PC-rich samples.


Assuntos
Biflavonoides/análise , Catequina/análise , Técnicas de Química Analítica/métodos , Análise de Alimentos/métodos , Extratos Vegetais/análise , Proantocianidinas/análise , Taninos/análise , 1-Butanol/análise , Acetona/análise , Ácido Clorídrico/química , Ferro/análise
16.
Chemosphere ; 240: 124821, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31546185

RESUMO

Anthropogenic CO2 emissions lead to seawater acidification that reportedly exerts deleterious impacts on marine organisms, especially on calcifying organisms such as mussels. A 21-day experiment focusing on the impacts of seawater acidification on the blue mussel, Mytilus edulis, was performed in this study, within which two acidifying treatments, CO2 enrichment and HCl addition, were applied. Two acidifying pH values (7.7 and 7.1) and the alteration of the key physiological processes of ingestion and digestion were estimated. To thoroughly investigate the impact of acidification on mussels, a histopathological study approach was adopted. The results showed that: (1) Seawater acidification induced either by CO2 enrichment or HCl addition impaired the gill structure. Transmission electron microscope (TEM) results suggested that the most obvious impacts were inflammatory lesions and edema, while more distinct alterations, including endoplasmic reticulum edema, nuclear condensation and chromatin plate-like condensation, were placed in the CO2-treated groups compared to HCl-treated specimens. The ciliary activity of the CO2 group was significantly inhibited simultaneously, leading to an obstacle in food intake. (2) Seawater acidification prominently damaged the structure of digestive glands, and the enzymatic activities of amylase, protease and lipase significantly decreased, which might indicate that the digestion was suppressed. The negative impacts induced by the CO2 group were more severe than that by the HCl group. The present results suggest that acidification interferes with the processes of ingestion and digestion, which potentially inhibits the energy intake of mussels.


Assuntos
Ácidos/efeitos adversos , Dióxido de Carbono/efeitos adversos , Ácido Clorídrico/efeitos adversos , Mytilus edulis/efeitos dos fármacos , Água do Mar/química , Ácidos/química , Animais , Dióxido de Carbono/farmacologia , Homeostase/efeitos dos fármacos , Ácido Clorídrico/farmacologia
17.
Chemosphere ; 238: 124598, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31446276

RESUMO

Sewage sludge dewatering is an efficient approach to reduce the volume of sludge for the subsequent disposal. In this study, a novel one-step acidification sludge dewatering method was developed with using oxalic acid as a conditioner. In laboratory-scale experiments with the dosage of 200 mg/g dry solid (DS), the normalized capillary suction time and the specific resistance to filtration were respectively decreased by 78.7% and 60.0% after 30 min of oxalic acid conditioning, much more efficient than those conditioned with sulfuric acid and hydrochloric acid at the same pH value. This superior dewatering performance was attributed to two factors. One was that oxalic acid could more efficiently promote the hydrolysis of polysaccharide, especially pectins, to release bound water. The other was that OA could dissolve more Fe3+ and Al3+, as well as form precipitate with Ca2+ in sludge, which may act as flocculants or co-precipitator for the subsequent sludge particles coagulation. In pilot-scale experiments, the water content of oxalic acid conditioned sludge cake was reduced to 60% under the optimum conditions, while the reagent cost was as low as 110.0 USD/t DS. This work provides a cost-effective and easy-operated sewage sludge disposal technique, and also sheds light on the potential of oxalic acid in environmental waste treatment.


Assuntos
Dessecação/métodos , Ácido Oxálico/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Filtração , Floculação , Ácido Clorídrico/química , Concentração de Íons de Hidrogênio , Hidrólise , Polissacarídeos/metabolismo , Ácidos Sulfúricos/química , Água/química
18.
Carbohydr Polym ; 229: 115524, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826475

RESUMO

Structure and properties of pectin can be affected by extraction methods. In this study, grapefruit peel pectins extracted by HCl (at pH 1 [P1], 2 [P2], and 3 [P3]) and NaOH (at pH 9 [P9], 10 [P10], and 11 [P11]) were prepared and characterized. Atomic force microscopy (AFM) provided direct evidence of complex nano-structural patterns of pectins and revealed cross-linked networks of P10 and P11. Small-angle X-ray scattering (SAXS) demonstrated that P1, P2, and P3 possessed a relatively extended conformation, whereas P9, P10, and P11 displayed a three-dimensional structure and folded conformation. The compact and extended conformations of P3 contributed to its high viscosity in solution and the stability of the formed emulsion (75%). Porous surface and larger three-dimensional nanostructure (Dmax: 23 nm) of P10 facilitated its ion-binding capacity. Our results provide valuable insight into relationship between extraction methods and structure-properties of pectin, facilitating design of functional pectins.


Assuntos
Citrus paradisi/metabolismo , Ácido Clorídrico/química , Pectinas/química , Hidróxido de Sódio/química , Emulsões/química , Frutas/metabolismo , Concentração de Íons de Hidrogênio , Nanoestruturas/química , Extratos Vegetais/metabolismo , Porosidade , Reologia , Espalhamento a Baixo Ângulo , Viscosidade , Difração de Raios X
19.
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi ; 37(11): 855-857, 2019 Nov 20.
Artigo em Chinês | MEDLINE | ID: mdl-31826555

RESUMO

Objective: To analyze the clinical characteristics caused by acute poisoning by inhalation of hydrogen chloride (HCl) and to raise awareness and treatment level of the disease. Methods: The clinical manifestations, imaging features, diagnosis, treatment and prognosis of 5 patients with acute HCl poisoning were analyzed retrospectively. Results: Among the 5 cases of HCl poisoning, 2 cases were severe poisoning, 3 cases were moderate poisoning. All patients were treated with corticosteroids and symptomatic treatment, one of them was treated with venovenous extracorporeal membrane oxygenation (VV-ECMO) . All patients were recovered and discharged from hospital. Conclusion: The lung damage of acute poisoning by inhalation of HCl is rapidly progressing, early detection and timely medical treatment can obtain a better prognosis.


Assuntos
Ácido Clorídrico , Pulmão , Envenenamento , Oxigenação por Membrana Extracorpórea , Humanos , Ácido Clorídrico/envenenamento , Pulmão/efeitos dos fármacos , Envenenamento/diagnóstico , Envenenamento/terapia , Prognóstico
20.
Molecules ; 24(23)2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31795117

RESUMO

This review presents the most recent developments on the synthesis of dipyrromethanes, covering classical synthetic strategies, using acid catalyzed condensation of pyrroles and aldehydes or ketones, and recent breakthroughs which allow the synthesis of these type of heterocycles with new substitution patterns.


Assuntos
Pirróis/síntese química , Aldeídos/química , Catálise , Técnicas de Química Sintética , Ácido Clorídrico , Índio/química , Estrutura Molecular , Pirróis/química
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