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1.
Sci Total Environ ; 832: 155116, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35398133

RESUMO

Acid mine drainage (AMD), a source of considerable environmental pollution worldwide, has prompted the development of many strategies to alleviate its effects. Unfortunately, the methods available for remedial treatment of AMD and the damage it cause are generally costly, labor-intensive, and time-consuming. Furthermore, such treatments may result in secondary pollution. Alternatively, treating the AMD problem at its source through pyrite surface passivation has become an important topic for research because it has the potential to reduce or prevent the generation of AMD and associated pollution. This review summarizes various pyrite anti-corrosion technologies, including the formation of various passivating coatings (inorganic, organic and organosilane) and carrier-microencapsulation. Several effective long-term passivators are identified, although many of them currently have important deficiencies that limit their practical application. Combining the mechanisms of existing passivation agents or new artificial materials, while considering environmental conditions, costs, and long-term passivation performance, is a feasible direction for future research.


Assuntos
Mineração , Sulfetos , Ácidos , Ferro
2.
Bioorg Med Chem Lett ; 66: 128734, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35436589

RESUMO

We previously described the discovery of a novel indole series compounds as oral SERD for ER positive breast cancer treatment. Further SAR exploration focusing on substitutions on indole moiety of compound 12 led to the discovery of a clinical candidate LX-039. We report herein its profound anti-tumor activity, desirable ER antagonistic characteristics combined with favorable pharmacokinetic and preliminary safety properties. LX-039 is currently in clinical trial (NCT04097756).


Assuntos
Neoplasias da Mama , Receptores de Estrogênio , Administração Oral , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Ensaios Clínicos como Assunto , Receptor alfa de Estrogênio , Feminino , Humanos , Indóis/farmacologia , Indóis/uso terapêutico , Moduladores Seletivos de Receptor Estrogênico/farmacologia
3.
Sci Total Environ ; 826: 154083, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35217046

RESUMO

East China Sea (ECS) is considered one of the largest dissolved oxygen (DO) depleted areas in the world's oceans. To assess the relative importance of water sources and biological processes to modulate low DO water over the ECS shelf, we conducted 7 cruises in the summers between 2004 and 2015. To cover a broad study area, observations were taken by both Chinese and Japanese research vessels in 2013, the consistent DO values were obtained in the intercalibration station from China and Japan. The subsurface/bottom water DO depletion was observed over both the inner and mid-outer shelves. In 2009 and 2013, the low DO (3-4.2 mg L-1) area covered ca. 4 × 104 km2 on the mid-outer shelf, comparable with the reported area of summer hypoxia off the Changjiang estuary. On the basis of a seven endmember mixing model using heavy rare earth elements, temperature and salinity data collected in 2013 and 2015, we determined that on the southern shelf the low DO water mainly originated from Kuroshio Subsurface Water (28-72%). Both the DO level in the dominant source water and organic matter (OM) remineralization modulated the formation and expansion of low DO waters. Oxygen-depleted bottom waters featured with high nutrients were both transported from the water's source regions and produced by OM remineralization on the mid-outer shelf. The estimated regenerated nutrient fluxes derived from OM respiration in the bottom water of the mid-outer shelf were equivalent to 18-37% of the nitrate and nitrite, and 2 to 5-fold the phosphorus, delivered from the Changjiang River in summer. The large quantity of regenerated nutrients from oxygen-depleted bottom waters on the mid-outer shelf could be utilized and support primary production in the adjacent oceans. Our findings provide valuable observation for simulation models of nutrient cycles and budgets in the ECS and adjacent oceans.


Assuntos
Estuários , Oxigênio , China , Nutrientes , Oxigênio/análise , Rios , Água
4.
Theranostics ; 12(1): 379-395, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34987651

RESUMO

Rationale: Poor ß cell proliferation is one of the detrimental factors hindering islet cell replacement therapy for patients with diabetes. Smad3 is an important transcriptional factor of TGF-ß signaling and has been shown to promote diabetes by inhibiting ß cell proliferation. Therefore, we hypothesize that Smad3-deficient islets may be a novel cell replacement therapy for diabetes. Methods: We examined this hypothesis in streptozocin-induced type-1 diabetic mice and type-2 diabetic db/db mice by transplanting Smad3 knockout (KO) and wild type (WT) islets under the renal capsule, respectively. The effects of Smad3KO versus WT islet replacement therapy on diabetes and diabetic kidney injury were examined. In addition, RNA-seq was applied to identify the downstream target gene underlying Smad3-regulated ß cell proliferation in Smad3KO-db/db versus Smad3WT-db/db mouse islets. Results: Compared to Smad3WT islet therapy, treatment with Smad3KO islets produced a much better therapeutic effect on both type-1 and type-2 diabetes by significantly lowering serum levels of blood glucose and HbA1c and protected against diabetic kidney injuries by preventing an increase in serum creatinine and the development of proteinuria, mesangial matrix expansion, and fibrosis. These were associated with a significant increase in grafted ß cell proliferation and blood insulin levels, resulting in improved glucose intolerance. Mechanistically, RNA-seq revealed that compared with Smad3WT-db/db mouse islets, deletion of Smad3 from db/db mouse islets markedly upregulated E2F3, a pivotal regulator of cell cycle G1/S entry. Further studies found that Smad3 could bind to the promoter of E2F3, and thus inhibit ß cell proliferation via an E2F3-dependent mechanism as silencing E2F3 abrogated the proliferative effect on Smad3KO ß cells. Conclusion: Smad3-deficient islet replacement therapy can significantly improve both type-1 and type-2 diabetes and protect against diabetic kidney injury, which is mediated by a novel mechanism of E2F3-dependent ß cell proliferation.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Fator de Transcrição E2F3/metabolismo , Células Secretoras de Insulina/metabolismo , Proteína Smad3/metabolismo , Animais , Células Secretoras de Insulina/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
5.
Food Chem Toxicol ; 156: 112522, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34438010

RESUMO

BACKGROUND AND OBJECTIVES: Dietary fibers have beneficial effects on human health through the interaction with gut microbiota. Larch wood arabinogalactan (LA-AG) is one kind of complex soluble dietary fibers that may be utilized by human gut microbiota. METHODS AND RESULTS: In this study, the LA-AG degradation by gut microbiota were characterized by investigating the change of LA-AG, microbiota composition, and the production of short-chain fatty acids (SCFAs), lactic acid, succinic acid, as well as volatile organic metabolites. During the fermentation, pH decreased continuously, along with the organic acids (especially acetic acid and lactic acid) accumulating. LA-AG was degraded by gut microbiota then some beneficial metabolites were produced. In addition, LA-AG inhibited the proliferation of some gut microbiota (Unclassified_Enterobacteriaceae and Citrobacter) and the accumulation of some metabolites (Sulfide and indole) released by gut microbiota. CONCLUSION: LA-AG was partly fermentable fibers with prebiotic potential for human gut health.


Assuntos
Galactanos/metabolismo , Microbioma Gastrointestinal/fisiologia , Prebióticos , Bactérias/classificação , Bactérias/metabolismo , Fibras na Dieta , Fezes/microbiologia , Fermentação , Galactanos/química , Humanos , Larix/química
6.
Clin Endocrinol (Oxf) ; 94(6): 949-955, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33548099

RESUMO

CONTEXT: Insulin resistance (IR) has been common in obese children, but the effect of different adiposity factors on IR is still unclear. OBJECTIVE: To evaluate the associations between IR with body mass index (BMI), waist circumference (WC), body fat mass (BFM), and body fat percentage (BFP) in obese children and adolescents. METHODS: A total of 224 simple obese children were included in this study, including 150 boys and 74 girls, aged 3-18 who were seen in the clinical nutrition outpatient of Xinhua Hospital from September 2012 to December 2019. Basic information, body composition and laboratory tests were collected. RESULTS: Compared with girls, boys had higher height, weight, BMI, WC, and BFM (P < 0.05), but on the contrary, boys' FINS and HOMA- IR were lower than girls' (P > 0.05). With the age increasing, height, weight, BMI, BFM, WC, HC, WHtR, FINS and HOMA-IR increased accordingly (P < 0.05). The results from univariate analysis and multiple linear regression analysis showed that the impact of BMI on IR was slightly lower than BFM, WC and HC, but higher than BFP, with adjusting for the effects of age, sex and lipid metabolism (P < 0.01). CONCLUSION: Overall adipose tissue, especially abdominal adipose tissue, is a powerful marker in inducing IR in obese children and adolescents. In addition, more attention should be paid to WC and BFM than BMI in obese people with IR.


Assuntos
Resistência à Insulina , Obesidade Pediátrica , Adiposidade , Adolescente , Índice de Massa Corporal , Criança , Feminino , Humanos , Masculino , Circunferência da Cintura
7.
Bioorg Med Chem Lett ; 30(22): 127601, 2020 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-33035677

RESUMO

Most estrogen receptor positive (ER +) breast cancers depend on ER signaling pathway to develop. Clinical application of SERD fulvestrant effectively degraded ER, blocked its function and prolonged progression free survival of ER + breast cancer patients. However, current SERD suffers from limited bioavailability, therefore is given as intramuscular (IM) injection. In this paper, we report herein a novel indole series compounds with nanomolar range ER degradation potencies and oral systemic exposures. Selected compounds suppressed tumor growth in vivo in ER + MCF7 breast cancer CDX model via p.o. administration. All those data supported further optimizations of this analog to develop preclinical candidate as oral SERD for ER + breast cancer's treatment.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Desenho de Fármacos , Indóis/farmacologia , Receptores de Estrogênio/antagonistas & inibidores , Administração Oral , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/síntese química , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Indóis/administração & dosagem , Indóis/síntese química , Células MCF-7 , Neoplasias Mamárias Experimentais/tratamento farmacológico , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Estrutura Molecular , Receptores de Estrogênio/metabolismo , Relação Estrutura-Atividade
8.
Artigo em Inglês | MEDLINE | ID: mdl-31972981

RESUMO

This study details the preparation of Fe-Mn binary oxide/mulberry stem biochar composite adsorbent (FM-MBC) from mulberry stems via the multiple activation by potassium permanganate, ferrous chloride, triethylenetetramine, and epichlorohydrin. The characteristics of FM-MBC had been characterized by SEM-EDS, BET, FT-IR, XRD, and XPS, and static adsorption batch experiments such as pH, adsorption time, were carried out to study the mechanism of Cr(VI) adsorption on FM-MBC and the impact factors. The results indicated that in contrast with the mulberry stem biochar (MBC), the FM-MBC has more porous on surface with a BET surface area of 74.73 m2/g, and the surface loaded with α-Fe2O3 and amorphization of MnO2 particles. Besides, carboxylic acid, hydroxyl, and carbonyls functional groups were also formed on the FM-MBC surface. At the optimal pH 2.0, the maximum adsorption capacity for Cr(VI) was calculated from the Langmuir model of 28.31, 31.02, and 37.14 mg/g at 25, 35, and 45 °C, respectively. The aromatic groups, carboxyls, and the hydroxyl groups were the mainly functional groups in the adsorption of Cr(VI). The mechanism of the adsorption process of FM-MBC for Cr(VI) mainly involves electrostatic interaction, surface adsorption of Cr(VI) on FM-MBC, and ion exchange.


Assuntos
Morus , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cromo , Concentração de Íons de Hidrogênio , Cinética , Compostos de Manganês , Óxidos , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Anal Chem ; 92(3): 2535-2542, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31766841

RESUMO

The feasibility of 16 types of rare-earth elements (REEs) containing Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu vapor, generated simultaneously, was demonstrated by nebulized film dielectric barrier discharge (NFDBD) in this work. Note that this is the first report on the simultaneous vapor generation of 16 types of REEs, which previously was difficult to realize. Combining it with inductively coupled plasma-mass spectroscopy (ICP-MS) as the sampling technique, a 4-fold to 10-fold improvement in the detection limits (LODs) of the REEs was observed, compared with the conventional solution nebulization, and no obvious interferences from other metal ions and the mutual interferences between REEs at the mg L-1 level were found. Compared with ultrasonic nebulization, microconcentric (MCN) and membrane-desolvation (Aridus) and electrothermal vaporization (ETV) for REEs sampling, this NFDBD sampling technique operates not only with low cost and low power, but also without any requirement of extra reagents and easy coupling with flow injection for volume limited samples. Under optimized conditions, the relative standard deviation (RSD) of 16 types of REEs determined at 5 µg L-1 was between 0.2% and 1.9%, and the LODs of REEs were between 0.002 ng L-1 and 0.422 ng L-1, depending on the element. This technique provides an alternative green and highly efficient vapor generation approach for the determination of REEs in environmental samples, especially in natural water.

10.
Neuroradiology ; 62(2): 161-166, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31654100

RESUMO

PURPOSE: The proportion of acute symptomatic lacunar infarction lesions that undergo cavitation and the factors influencing cavity formation are yet unclear, particularly in the Chinese population. Hence, we investigated changes in the diameter of acute lacunar infarction lesions and identified the risk factors for the progression of these lesions. METHODS: A total of 160 patients (mean age 66 years) with acute symptomatic lacunar infarction lesions underwent two magnetic resonance imaging (MRI) examinations: diffusion-weighted imaging (DWI) at onset (lesion diameter < 20 mm) and T2-weighted imaging/fluid-attenuated inversion recovery sequences at follow-up (median follow-up time 389 days). Lacunar infarction lesion progression was categorized as complete cavitation (lacune), partial cavitation, white matter lesion (WML), or disappearance of the lesion. The risk factors for cavity formation were evaluated. RESULTS: Upon follow-up MRI, lesions had changed to lacunes in 20 (12.5%) patients, partial cavitation in 23 (14.4%), WMLs in 97 (60.6%), and had disappeared in 20 (12.5%). Lacune formation was related to hypertension (P = 0.026); cavity (lacune and partial cavitation) formation was related to diabetes (P = 0.009) and diameter change (P = 0.015). CONCLUSIONS: Approximately a quarter of the acute symptomatic lacunar infarction lesions observed with follow-up MRI were cavitated. Hypertension was negatively associated with lacune formation; diabetes and diameter change were negatively associated with cavity formation.


Assuntos
Imageamento por Ressonância Magnética/métodos , Acidente Vascular Cerebral Lacunar/diagnóstico por imagem , Idoso , China , Imagem de Difusão por Ressonância Magnética , Progressão da Doença , Feminino , Humanos , Masculino , Estudos Retrospectivos , Fatores de Risco
11.
Am J Physiol Renal Physiol ; 317(5): F1217-F1223, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31566437

RESUMO

Highly purified mouse glomeruli are of great value for studying glomerulus-associated kidney diseases. Here, we developed a simple and rapid procedure for mouse glomerular isolation with large quantity and high purity based on the combination of size-selective sieving and differential adhesion techniques, which we termed the "differential adhesion method." In this method, mouse renal cortices were minced and digested with collagenase. Glomeruli were disassociated from tubules by successive sieving through 105-, 75-, and 40-µm cell strainers. The retained glomeruli-rich preparation on the 40-µm strainer was rinsed into a cell culture dish to allow tubules to adhere quickly to the dish while leaving most glomeruli floating (termed "differential adhesion"). The floating glomerular fraction was then subjected to another wash through the 40-µm strainer followed by an additional differential adhesion step to obtain highly purified glomeruli with yields of 8,357 ± 575 and purity of 96.1 ± 1.8% from one adult C57BL/6 mouse. The purity of the isolated glomeruli was further confirmed by high expression of the podocyte marker nephrin without detectable tubular marker cadherin-16. Importantly, we also found that although both the quantity and purity of the isolated glomeruli by this and the established Dynabeads method were comparable, glomeruli isolated by the current method showed much less inflammatory stress in terms of proinflammatory cytokine expression than the Dynabeads method. In conclusion, we established a newly mouse glomerular isolation method that is simple, rapid, cost effective, and productive. It provides an advanced methodology for research into glomerulus-related kidney diseases in the mouse.


Assuntos
Separação Celular/métodos , Glomérulos Renais/anatomia & histologia , Azul Alciano , Animais , Células Cultivadas , Corantes , Técnicas Histológicas , Camundongos , Reprodutibilidade dos Testes , Coloração e Rotulagem
12.
Ecotoxicol Environ Saf ; 185: 109700, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31557569

RESUMO

In this study, heavy metals including Cd, Pb, Zn, Mn, Cu, Ni, Cr, As, and Hg, in the surface sediment (0-10 cm) of the Huixian wetland in a karst region were investigated in terms of their spatial distribution, ecological risks, and possible sources. Samples were collected from 13 typical sites throughout the Huixian wetland and were analyzed via inductively coupled plasma-mass spectrometry. The results revealed that the mean concentrations of Cd, Pb, Mn, Cr, As, and Hg were higher than the background and Chinese safe standard values. Based on spatial distribution and ecological risk, the study area was differentiated into three groups of sites with the following order of risk: group 3 > group 2 > group 1. The observed concentrations fluctuated slightly with depth. However, an irregular decreasing trend in the concentration with soil depth was observed among the groups. Multivariate statistical analyses showed that the high accumulation of Cd, Pb, Zn and Cu in the sediments of group 3 sites is due to the natural ancient deposition of minerals rich in heavy metals, while the accumulation of Mn, Cr, As, and Hg is attributed to an anthropogenic origin. Agricultural activities, the use of fertilizers and, pesticides, and local automobile repair stations most probably enriched these heavy metals in the Huixian wetland sediments. Hg and Cd have the highest potential ecological risk, which follows the order Hg > Cd > Pb > As > Ni > Cu > Cr > Mn > Zn. The mean geoaccumulation index (Igeo) values of Pb (0.48) and Hg (1.12) suggested moderate contamination in the study area.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Áreas Alagadas , China , Ecologia , Análise Multivariada , Medição de Risco , Solo/química
13.
Sci Rep ; 9(1): 8880, 2019 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222038

RESUMO

In this study, the adsorption and UV photocatalytic degradation of atrazine using nano-TiO2 particles were studied systematically, and the colloidal stability of nano-TiO2 particles in solution was also investigated to reveal the removal mechanism. Experiments which contained the first 6.0 hours darkness and 4.0 hours UV illumination later were conducted at different concentrations of Ca2+ and/or fulvic acids (FA) at pH = 7.0. Results showed that the adsorption rate of atrazine onto nano-TiO2 particles decreased with the increase of Ca2+ and/or FA concentrations, which could be explained well by the colloidal stability of nanoparticles. When the solution contained Ca2+ or Ca2+-FA, the nanoparticles were aggregated together leading to the decrease of the contact surface area. Besides, there existed competitive adsorption between FA and atrazine on the particle surface. During photocatalytic degradation, the increase of Ca2+ and/or FA concentration accelerated the aggregation of nano-TiO2 particles and that reduced the degradation efficiency of atrazine. The particle sizes by SEM were in accordance with the aggregation degree of nanoparticles in the solutions. Sedimentation experiments of nano-TiO2 particles displayed that the fastest sedimentation was happened in the CaCl2 and FA coexistent system and followed by CaCl2 alone, and the results well demonstrated the photodegradation efficiency trends of atrazine by nano-TiO2 particles under the different sedimentation conditions.

14.
J Cell Mol Med ; 23(5): 3495-3504, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30821111

RESUMO

Glycyrrhizin is a bioactive triterpenoid saponin extracted from a traditional Chinese medicinal herb, glycyrrhiza, and has been reported to protect the organs such as liver and heart from injuries. However, there is no report about the effects of glycyrrhizin on atrophic age-related macular degeneration (AMD). This study investigated the effects of glycyrrhizin on retinal pigment epithelium (RPE) in vitro and retina of mice in vivo treated with sodium iodate (SI). Glycyrrhizin significantly inhibited SI-induced reactive oxygen species (ROS), and decreased apoptosis of RPE in vitro. The underlying mechanisms included increased phosphorylation of Akt, and increased expression of nuclear factor erythroid 2-related factor2 (Nrf-2) and HO-1, thereby protecting RPE from SI-induced ROS and apoptosis. Furthermore, glycyrrhizin significantly decreased the apoptosis of retinal cells in vivo, resulting in the inhibition of thinning of retina, decreasing the number of drusen and improving the function of retina. These findings suggested that glycyrrhizin may be a potential candidate for the treatment of atrophic AMD in clinical practice.


Assuntos
Ácido Glicirrízico/farmacologia , Heme Oxigenase-1/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Retina/efeitos dos fármacos , Doenças Retinianas/prevenção & controle , Epitélio Pigmentado da Retina/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Humanos , Iodatos/toxicidade , Masculino , Camundongos Endogâmicos C57BL , Substâncias Protetoras/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Retina/metabolismo , Retina/patologia , Doenças Retinianas/induzido quimicamente , Doenças Retinianas/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Epitélio Pigmentado da Retina/patologia , Transdução de Sinais/efeitos dos fármacos
15.
Artigo em Inglês | MEDLINE | ID: mdl-31888127

RESUMO

Atrazine is a kind of triazine herbicide that is widely used for weed control due to its good weeding effect and low price. The study of atrazine removal from the environment is of great significance due to the stable structure, difficult degradation, long residence time in environment, and toxicity on the organism and human beings. Therefore, a number of processing technologies are developed and widely employed for atrazine degradation, such as adsorption, photochemical catalysis, biodegradation, etc. In this article, with our previous research work, the progresses of researches about the treatment technology of atrazine are systematically reviewed, which includes the four main aspects of physicochemical, chemical, biological, and material-microbial-integrated aspects. The advantages and disadvantages of various methods are summarized and the degradation mechanisms are also evaluated. Specially, recent advanced technologies, both plant-microbial remediation and the material-microbial-integrated method, have been highlighted on atrazine degradation. Among them, the plant-microbial remediation is based on the combined system of soil-plant-microbes, and the material-microbial-integrated method is based on the synergistic effect of materials and microorganisms. Additionally, future research needs to focus on the excellent removal effect and low environmental impact of functional materials, and the coordination processing of two or more technologies for atrazine removal is also highlighted.


Assuntos
Atrazina/química , Biodegradação Ambiental , Herbicidas/química , Plantas/química , Microbiologia do Solo , Poluentes do Solo/química
16.
Appl Microbiol Biotechnol ; 102(17): 7597-7610, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29909573

RESUMO

A novel bionanomaterial comprising Saccharomyces cerevisiae (S. cerevisiae) and Fe3O4 nanoparticles encapsulated in a sodium alginate-polyvinyl alcohol (SA-PVA) matrix was synthesized for the efficient removal of atrazine from aqueous solutions. The effects of the operating parameters, nitrogen source, and glucose and Fe3+ contents on atrazine removal were investigated, and the intermediates were detected by gas chromatography-mass spectrometry (GC-MS). In addition, the synthesized Fe3O4 particles were characterized by XRD, EDX, HR-TEM, FTIR, and hysteresis loops, and the bionanomaterial was characterized by SEM. The results showed that the maximum removal efficiency of 100% was achieved at 28 °C, a pH of 7.0, and 150 rpm with an initial atrazine concentration of 2.0 mg L-1 and that the removal efficiency was still higher than 95.53% even when the initial atrazine concentration was 50 mg L-1. Biodegradation was demonstrated to be the dominant removal mechanism for atrazine because atrazine was consumed as the sole carbon source for S. cerevisiae. The results of GC-MS showed that dechlorination, dealkylation, deamination, isomerization, and mineralization occurred in the process of atrazine degradation, and thus, a new degradation pathway was proposed. These results indicated that this bionanomaterial has great potential for the bioremediation of atrazine-contaminated water.


Assuntos
Atrazina/isolamento & purificação , Compostos Férricos/química , Herbicidas/isolamento & purificação , Nanopartículas de Magnetita/química , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismo , Poluentes Químicos da Água/isolamento & purificação , Alginatos/química , Biodegradação Ambiental , Carbono , Nitrogênio , Álcool de Polivinil/química
17.
Bioresour Technol ; 260: 196-203, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29625292

RESUMO

A novel magnetic bionanomaterial, Penicillium sp. yz11-22N2 doped with nano Fe3O4 entrapped in polyvinyl alcohol-sodium alginate gel beads (PFEPS), was successfully synthesized. The factors including nutrient substance, temperature, pH, initial concentrations of atrazine and rotational speeds were presented and discussed in detail. Results showed that the highest removal efficiency of atrazine by PFEPS was 91.2% at 8.00 mg/L atrazine. The maximum removal capacity for atrazine was 7.94 mg/g. Meanwhile, it has been found that most of atrazine were removed by metabolism and degradation of Penicillium sp. yz11-22N2, which could use atrazine as the sole source of either carbon or nitrogen. Degradation kinetics of atrazine conformed to first-order kinetics model. The intermediates indicated that the possible pathway for atrazine degradation by PFEPS mainly included hydrolysis dechlorination, dealkylation, side-chain oxidation and ring-opening.


Assuntos
Atrazina , Biodegradação Ambiental , Penicillium , Carbono , Nitrogênio , Álcool de Polivinil
18.
Chemosphere ; 200: 380-387, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29499518

RESUMO

Saccharomyces cerevisiae and nanoparticles of iron oxide (Fe3O4) which were linked with chitosan (CS) through epichlorohydrin (ECH) were encapsulated in calcium alginate to prepare a novel type of bionanocomposites. Characterization results showed that the Fe3O4-ECH-CS nanoparticles were quasi-spherical with an average diameter of 30 nm to which chitosan was successfully attached through epichlorohydrin. The saturation magnetization value of the nanoparticles was 21.88 emu/g, and ferrous and ferric irons were simultaneously observed in the magnetic nanoparticles. Data of atrazine removal by yeasts showed that both inactivated and live yeasts could decrease the concentration of atrazine effectively. The inactivated yeasts achieved 20% removal rate, which indicated that adsorption by the yeasts also played a role in the removal. Removal efficiency of atrazine was maximized at 88% under 25 °C, pH of 7 and an initial atrazine concentration of 2 mg/L. When the magnetic bionanocomposite was recycled and reused twice, only 12% and 20% drop in removal efficiency was observed at the first time and the second time severally. So, atrazine could be used by the yeasts as the sole carbon source for growth and multiplication, and both adsorption and biodegradation by the bionanocomposite contributed to atrazine removal.


Assuntos
Atrazina/isolamento & purificação , Biodegradação Ambiental , Quitosana/química , Poluentes Ambientais/isolamento & purificação , Compostos Férricos/química , Magnetismo , Nanocompostos/química , Saccharomyces cerevisiae/metabolismo , Atrazina/análise , Atrazina/química , Poluentes Ambientais/análise , Poluentes Ambientais/química , Saccharomyces cerevisiae/citologia
19.
Trends Biotechnol ; 36(7): 673-685, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29500005

RESUMO

Volatile organic compounds (VOCs) are significant atmospheric pollutants that cause environmental and health risks. Waste gases polluted with multiple VOCs often need to be purified simultaneously in biofilters, which may lead to antagonistic, neutral, or synergistic effects on removal performance. Antagonism limits the application of biofilters to simultaneous treatment of multiple VOCs, while synergism has not yet been fully exploited. We review the interactions among multiple target pollutants and the changes in the bioavailability and biodegradability of substrates that are responsible for substrate interactions. Potential strategies for enhancing biofilter performance are then discussed. Finally, we propose further efforts to alleviate antagonism by enhancing bioavailability and biodegradability, and discuss possible challenges to take advantage of synergism.


Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Filtração/métodos , Fungos/metabolismo , Compostos Orgânicos Voláteis , Biofilmes , Repressão Catabólica , Poluentes Ambientais/química , Poluentes Ambientais/metabolismo , Gases/química , Interações Hidrofóbicas e Hidrofílicas , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo , Água/química
20.
Opt Lett ; 43(4): 943-946, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-29444033

RESUMO

A high-power, high-repetition-rate, broadband tunable femtosecond optical parametric oscillator (OPO) is constructed based on KTiOAsO4 crystal, pumped by a 75.5 MHz mode-locked Yb:KGW laser. With 7 W pump power, the OPO generates as much as 2.32 W of signal power at 1.55 µm and 1.31 W of idler power at 3.05 µm, corresponding to a total conversion efficiency of 51.8%. Operating at 151 MHz repetition rate, the wavelength of the signal covers 1.41-1.71 µm with a tunable idler range of 2.61-3.84 µm. The idler bandwidth is more than 180 nm over the entire mid-infrared range. By compensating intracavity dispersion, the signal pulse has a nearly Fourier transform-limited duration of 129 fs at 1.52 µm.

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