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1.
Chemosphere ; 286(Pt 2): 131825, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34375830

RESUMO

Owing to the escalating threat of criminal activities and pollution aroused by 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP), development of a proficient sensor for the detection of these explosives is highly demanded. Herein, a water-soluble ionic liquid-tagged fluorescent probe, 1-ethyl-3-(3-formyl-4-hydroxybenzyl)-1H-benzimidazol-3-ium chloride (EB-IL) has been designed and synthesized for the detection of TNT and TNP in 100% aqueous medium. The EB-IL fluorescent probe displayed strong cyan-blue fluorescence at 500 nm which gets quenched upon the addition of TNT/TNP over other concomitant nitro-compounds. The distinct binding response of EB-IL towards TNT could be due to the formation of hydrogen bonding between the acidic proton of benzimidazolium (C2-H) and nitro group of TNT. Meanwhile, the selective binding of TNP with EB-IL could be due to the exchange of counter Cl- anion of EB-IL with picrate anion. The fluorescence quenching of EB-IL by TNT could be attributed to the resonance energy transfer (RET) and that of TNP is ascribed to the anion-exchange process. The developed sensor is extremely selective and sensitive towards TNT and TNP with high quenching constants of 1.94 × 105 M-1 and 2.32 × 106 M-1 and shows a lower detection limit of 159 nM and 282 nM, respectively.


Assuntos
Líquidos Iônicos , Trinitrotolueno , Corantes Fluorescentes , Picratos , Água
2.
Talanta ; 236: 122824, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635214

RESUMO

Ultra-sensitive detection of 2,4,6-trinitrotoluene (TNT) plays an important role in society security and human health. The Raman probe molecule p-aminothiophenol (PATP) can interact with TNT in three ways to form a TNT-PATP complex. In this paper, a 'sandwich' structure was developed to detect TNT with high sensitivity. Au nano-pillar arrays (AuNPAs) substrates modified by low-concentration PATP through Au-S bonds were acted as capture probe for TNT. Meanwhile, Ag nano-particles (AgNPs) modified by PATP at higher concentration were employed as tags for surface-enhanced Raman scattering (SERS). The formation of the TNT-PATP complex is not only the means by which AuNPAs substrates recognize and capture TNT, but also links the SERS tags to TNT, forming an AuNPAs-TNT-AgNPs 'sandwich' structure. The Raman signal of PATP was greatly enhanced mainly because novel 'hot spots' formed between the AuNPAs and AgNPs of the 'sandwich' structure. The Raman signal of PATP was further amplified by the chemical enhancement effect induced by the TNT-PATP complex formation. Based on this mechanism, the limit of detection (LOD) of TNT was determined from the Raman signal of PATP. The LOD reached 10-9 mg/mL (4.4 × 10-12 M), much lower than that suggested by the US Environmental Protection Agency (88 nM). Moreover, TNT was selectively detected over several TNT analogues 2,4-dinitrotoluene (DNT), p-nitrotoluene (NT) and hexogen (RDX). Finally, the 'sandwich' structure was successfully applied to TNT detection in environmental water and sand.


Assuntos
Análise Espectral Raman , Trinitrotolueno , Humanos , Limite de Detecção , Prata , Trinitrotolueno/análise , Estados Unidos
3.
Talanta ; 233: 122498, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215116

RESUMO

Carbon dots have been a promising nano-carbon material with many advantages, and attracted many more attentions. This study designed a new chemosensor integrating the strong fluorescent property of carbon dots and the magnetism of amino-functionalized magnetic core-shell nanomaterial, Fe@SiO2-NH2 for determination of 2,4,6-trinitrotoluene (TNT). In this system, fluorescent carbon dots interacted with amino groups on the surface of amino-functionalized magnetic core-shell nanomaterial leading to fluorescence quenching of carbon dots, appearance of TNT competitively replaced of carbon dots on the surface of the magnetic material through forming a Meisenheimer complex. This sensor exhibits excellent selectivity and sensitivity for TNT, and which provided a good dynamic linear range for TNT from 10 to 2000 ng mL-1. The experiments demonstrate a low detection limit of 2.15 ng mL-1. The intra-day precisions for 25, 100 and 500 ng mL-1 were 4.6, 2.3 and 0.5% (RSD, n = 6), inter-day precisions for 25, 100 and 500 ng mL-1 were 4.2, 2.5 and 0.9% (RSD, n = 6), respectively. The developed sensor was validated with river water, dust, and soil samples, and the achieved spiked recoveries were immensely satisfied from 98.1% to 102.0%. The Fe@SiO2-NH2 possessed excellent reusability. This sensor exhibits that it is simple, sensitive and selective, and will be a vital analytical tool for TNT in many fields.


Assuntos
Nanoestruturas , Pontos Quânticos , Trinitrotolueno , Carbono , Limite de Detecção , Dióxido de Silício
4.
Talanta ; 233: 122596, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215084

RESUMO

Detection of explosives at trace levels is crucial for security purposes because of increasing worldwide terrorist threats at public places. Previously, a hollow cathode discharge (HCD) ion source has been fabricated for detection of explosives. Recently, the HCD ion source has been modified for a dual pressures operating system and coupled to a linear ion trap MS to analyze explosives simultaneously. Here, trinitrotoluene (TNT), nitroglycerin (NG), pentaerythritol tetranitrate (PETN) and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) were taken as model explosive compounds and the mass spectra were recorded in the negative mode ionization. At the higher ion source pressure (~28.0-30.0 Torr), NG, PETN and RDX gave adduct ions with the NO3- ion while TNT showed the [TNT + NO3-HNO2]- (m/z 242) simultaneously. However, NG and PETN did not give any ion signals at the lower ion source pressure (~0.8-1.0 Torr) while TNT exhibited its molecular ion, [TNT]-• (m/z 227), as a major ion through electron attachment and RDX showed fragment ions that followed electron capture dissociation concurrently. The modified HCD ion source exhibited better sensitivity in simultaneous detection and quantification of the explosives. The NO3- and NO2- as reagent ions in the air HCD plasma form stable adduct ions with the NG, PETN and RDX even with TNT at the higher temperature (140-200 °C). The formation of the NO3-, NO2- in the HCD plasma also causes the formation of [TNT-H]- (m/z 226) at the higher ion source pressure. The inner metallic surface of the hollow tube assists the Birch reduction type reaction that results in the formation of hydride ion of the TNT, [TNT + H]- (m/z 228). No significant difference in the spectral pattern for simultaneous and individual measurements for the explosives was observed at the higher ion source pressure. Therefore, it may conclude that the present modified HCD ion source can be used for simultaneous detection and quantification of the explosive compounds at trace and/or ultra-trace levels using air as a carrier gas.


Assuntos
Substâncias Explosivas , Tetranitrato de Pentaeritritol , Trinitrotolueno , Eletrodos , Humanos , Alta do Paciente
5.
Environ Pollut ; 285: 117478, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34087636

RESUMO

This experiment was conducted to evaluate the ecotoxicity of typical explosives and their mechanisms in the soil microenvironment. Here, TNT (trinitrotoluene), RDX (cyclotrimethylene trinitramine), and HMX (cyclotetramethylene tetranitramine) were used to simulate the soil pollution of single explosives and their combination. The changes in soil enzyme activity and microbial community structure and function were analyzed in soil, and the effects of explosives exposure on the soil metabolic spectrum were revealed by non-targeted metabonomics. TNT, RDX, and HMX exposure significantly inhibited soil microbial respiration and urease and dehydrogenase activities. Explosives treatment reduced the diversity and richness of the soil microbial community structure, and the microorganisms able to degrade explosives began to occupy the soil niche, with the Sphingomonadaceae, Actinobacteria, and Gammaproteobacteria showing significantly increased relative abundances. Non-targeted metabonomics analysis showed that the main soil differential metabolites under explosives stress were lipids and lipid-like molecules, organic acids and derivatives, with the phosphotransferase system (PTS) pathway the most enriched pathway. The metabolic pathways for carbohydrates, lipids, and amino acids in soil were specifically inhibited. Therefore, residues of TNT, RDX, and HMX in the soil could inhibit soil metabolic processes and change the structure of the soil microbial community.


Assuntos
Substâncias Explosivas , Microbiota , Poluentes do Solo , Trinitrotolueno , Azocinas , Substâncias Explosivas/análise , Substâncias Explosivas/toxicidade , Metaboloma , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Triazinas/análise , Trinitrotolueno/análise , Trinitrotolueno/toxicidade
6.
Ecotoxicol Environ Saf ; 220: 112407, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119926

RESUMO

2,4,6-trinitrotoluene (TNT) and cobalt (Co) contaminants have posed a severe environmental problem in many countries. Phytoremediation is an environmentally friendly technology for the remediation of these contaminants. However, the toxicity of TNT and cobalt limit the efficacy of phytoremediation application. The present research showed that expressing the Acidithiobacillus ferrooxidans single-strand DNA-binding protein gene (AfSSB) can improve the tolerance of Arabidopsis and tall fescue to TNT and cobalt. Compared to control plants, the AfSSB transformed Arabidopsis and tall fescue exhibited enhanced phytoremediation of TNT and cobalt separately contaminated soil and co-contaminated soil. The comet analysis revealed that the AfSSB transformed Arabidopsis suffer reduced DNA damage than control plants under TNT or cobalt exposure. In addition, the proteomic analysis revealed that AfSSB improves TNT and cobalt tolerance by strengthening the reactive superoxide (ROS) scavenging system and the detoxification system. Results presented here serve as strong theoretical support for the phytoremediation potential of organic and metal pollutants mediated by single-strand DNA-binding protein genes. SUMMARIZES: This is the first report that AfSSB enhances phytoremediation of 2,4,6-trinitrotoluene and cobalt separately contaminated and co-contaminated soil.


Assuntos
Cobalto/metabolismo , Proteínas de Ligação a DNA/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Poluentes do Solo/metabolismo , Trinitrotolueno/metabolismo , Acidithiobacillus/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Biodegradação Ambiental , Proteínas de Ligação a DNA/genética , Lolium/genética , Lolium/metabolismo , Plantas Geneticamente Modificadas/genética , Proteômica
7.
Analyst ; 146(14): 4615-4621, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34164639

RESUMO

The detection of explosive nitroaromatic compounds has caused worldwide concern for human safety. In this study, we introduce a fluorescent biosensor based on porous biocompatible microspheres loaded with a bioreporter for the detection of nitroaromatic compounds. Poly(lactic-co-glycolic acid) microbeads were designed as biosensors embedded with the bacterial bioreporters. The genetically engineered bacterial bioreporter can express a green fluorescent protein in response to nitroaromatic compounds (e.g., trinitrotoluene and dinitrotoluene). The modified surface structure in microbeads provides a large surface area, as well as easy penetration, and increases the number of attached bioreporters for enhanced fluorescent signals of biosensors. Moreover, the addition of the M13 bacteriophage in open porous microbeads significantly amplified the fluorescence signal for detection by the π-π interaction between peptides in the M13 bacteriophage and nitroaromatic compounds. The modification of the surface morphology, as well as the genetically engineered M13 phage, significantly amplifies the fluorescence signal, which makes the detection of explosives easier, and has great potential for the stand-off remote sensing of TNT buried in the field.


Assuntos
Substâncias Explosivas , Trinitrotolueno , Bactérias , Glicolatos , Glicóis , Humanos , Microesferas , Porosidade
8.
Appl Microbiol Biotechnol ; 105(10): 4329-4337, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33942130

RESUMO

Landmines and other explosive remnants of war pose a global humanitarian problem that claims numerous casualties long after the conflict has ended. As there are no acceptable methodologies for the remote discovery of such devices, current detection practices still require the risky presence of personnel in the minefield. We have recently described bacterial sensor strains capable of reporting the existence of 2,4-dinitrotoluene (DNT) vapors in the soil above 2,4,6-trinitrotoluene (TNT)-based landmines, by generating a bioluminescent or a fluorescent signal. This may allow the identification of landmine location by remote imaging of an area over which the bacteria have been spread. In the study reported herein, we have improved the DNT-detection capabilities of these sensor strains by combining two DNT-responsive Escherichia coli gene promoters, yqjF and azoR, and subjecting them to three cycles of random mutagenesis by error-prone PCR, combined with segmentation and rearrangement ("DNA shuffling"). The activity of selected modified promoters was evaluated with the Aliivibrio fischeri and Photobacterium leiognathi luxCDABEG gene cassettes as the bioluminescent reporters, exhibiting a ten-fold background reduction that has led to a three-fold decrease in detection threshold. Signal intensity was further enhanced by modifying the ribosomal binding site of the yqjF gene promoter. The superior DNT detection capabilities on a solid matrix by the improved sensor strain were demonstrated. KEY POINTS: • Performance of microbial sensor strains for buried explosives was molecularly enhanced. • Manipulations included random mutagenesis, "DNA shuffling," and RBS reprogramming. • The re-engineered constructs exhibited superior detection of trace explosives.


Assuntos
Técnicas Biossensoriais , Substâncias Explosivas , Trinitrotolueno , Bactérias , Embaralhamento de DNA , Mutagênese , Photobacterium
9.
Chemosphere ; 281: 130842, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34023765

RESUMO

The aim of this study was to reveal the mechanism underlying the toxicity of TNT (trinitrotoluene), RDX (cyclotrimethylene trinitroamine), and HMX (cyclotetramethylene tetranitramine) explosives pollution in plants. Here, the effects of exposure to these three explosives were examined on chlorophyll fluorescence, antioxidant enzyme activity, and the metabolite spectrum in alfalfa (Medicago sativa) plants. The degradation rates for TNT, RDX, and HMX by alfalfa were 26.8%, 20.4%, and 18.4%, respectively, under hydroponic conditions. TNT caused damage to the microstructure of the plant roots and inhibited photosynthesis, whereas RDX and HMX induced only minor changes. Exposure to any of the three explosives caused disturbances in the oxidase system. Non-targeted metabolomics identified a total of 6185 metabolites. TNT exposure induced the appearance of 609 differentially expressed metabolites (189 upregulated, 420 downregulated), RDX exposure induced 197 differentially expressed metabolites (155 upregulated and 42 downregulated), and HMX induced 234 differentially expressed metabolites (132 upregulated and 102 downregulated). Of these differentially expressed metabolites, lipids and lipid-like molecules were the main metabolites induced by explosives poisoning. TNT mainly caused significant changes in the alanine, aspartate, and glutamate metabolism metabolic pathways, RDX mainly caused disorders in the arginine biosynthesis metabolic pathway, and HMX disrupted the oxidative phosphorylation metabolic pathway. Taken together, the results show that exposure to TNT, RDX, and HMX leads to imbalances in plant photosynthetic characteristics and antioxidant enzyme systems, changes the basic metabolism of plants, and has significant ecotoxicity effects.


Assuntos
Trinitrotolueno , Azocinas , Medicago sativa , Triazinas , Trinitrotolueno/toxicidade
10.
Oncologist ; 26(9): e1555-e1566, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33987952

RESUMO

BACKGROUND: Total neoadjuvant therapy (TNT) is a novel approach for locally advanced rectal cancer (LARC), which attempts to deliver both systemic chemotherapy and neoadjuvant chemoradiotherapy prior to surgery. However, its efficacy and safety remain controversial in randomized controlled trials (RCTs). We conducted this meta-analysis to assess such concerns. MATERIALS AND METHODS: Head-to-head phase II/III RCTs were searched in Embase, PubMed, Web of Science, and the Cochrane Library, as well as other sources. The primary endpoint was pathologic complete response (pCR). Secondary endpoints were disease-free survival (DFS), overall survival (OS), local recurrence-free survival, distant metastasis-free survival, and the R0 resection rate. RESULTS: Eight phase II/III RCTs involving 2,196 patients with LARC were assessed. The primary analysis demonstrated a statistically significant improvement in the pCR rate for TNT treatment (odds ratio, 1.77; 95% confidence interval [CI], 1.28-2.45; p = .0005). TNT treatment also showed improvements in DFS and OS outcomes compared with standard chemoradiotherapy (hazard ratio [HR], 0.83; 95% CI, 0.72-0.96; p = .03 and HR, 0.88; 95% CI, 0.74-1.05; p = .15). In addition, TNT treatment showed significant efficacy in reducing the risk of distant metastasis (HR, 0.81; 95% CI, 0.68-0.95; p = .012). CONCLUSION: The overall pCR rate may be improved with TNT compared with standard treatment. The TNT strategy may also improve DFS and OS and reduce the risk of distant metastasis. IMPLICATIONS FOR PRACTICE: Locally advanced rectal cancer (LARC) is a relatively common disease, with a poor prognosis because of its high metastatic potential. The role of total neoadjuvant therapy (TNT) has always been controversial. This meta-analysis found that TNT in LARC is associated with a significant improvement in overall pathologic complete response rate, disease-free survival, overall survival, and distant metastasis-free survival compared with standard treatment. TNT is a promising strategy for LARC, especially for patients who have little desire for surgery.


Assuntos
Neoplasias Retais , Trinitrotolueno , Quimiorradioterapia , Intervalo Livre de Doença , Humanos , Terapia Neoadjuvante , Neoplasias Retais/tratamento farmacológico , Neoplasias Retais/radioterapia , Reto , Resultado do Tratamento
12.
J Environ Sci (China) ; 103: 69-79, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33743920

RESUMO

Nitroaromatic explosives are major pollutants produced during wars that cause serious environmental and health problems. The removal of a typical nitroaromatic explosive, 2,4,6-trinitrotoluene (TNT), from aqueous solution, was conducted using a new recyclable magnetic nano-adsorbent (Fe@SiO2NH2). This adsorbent was prepared by grafting amino groups onto Fe@SiO2 particles with a well-defined core-shell structure and demonstrated monodispersity in solution. The removal performance of the nano-adsorbent towards TNT was found to be 2.57 and 4.92 times higher than that towards two analogous explosives, 2,4-dinitrotoluene (2,4-DNT) and 2-nitrotoluene (2-NT), respectively, under neutral conditions. The difference in the removal performance among the three compounds was further compared in terms of the effects of different conditions (pH value, ionic strength, humic acid concentration, adsorbent modification degree and dosage, etc.) and the electrostatic potential distributions of the three compounds. The most significant elevation is owing to modification of amino on Fe@SiO2 which made a 20.7% increase in adsorption efficiency of TNT. The experimental data were well fit by the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model, indicating multilayer adsorption on a heterogeneous surface. The experimental results and theoretical considerations show that the interactions between Fe@SiO2NH2 NPs and TNT correspond to dipole-dipole and hydrophobic interactions. These interactions should be considered in the design of an adsorbent. Furthermore, the adaptability to aqueous environment and excellent regeneration capacity of Fe@SiO2NH2 NPs makes these remediation materials promising for applications.


Assuntos
Trinitrotolueno , Poluentes Químicos da Água , Adsorção , Ferro , Dióxido de Silício , Trinitrotolueno/análise , Poluentes Químicos da Água/análise
13.
J Environ Manage ; 287: 112342, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33740743

RESUMO

The production of 2,4,6-trinitrotoluene (TNT) produces a great deal of waste water, and dinitrotoluene sulfonates (DNTs) are the main pollutants in its waste. This paper presents a pilot investigation on the geochemical transformation of DNTs affected by historical wastewater spillage from a typical TNT production company in Northwest China. In the horizontal direction, DNTs diffused from the evaporation pond to the surrounding area of the site, and the concentration of DNTs in the evaporation pond surface soil exceeded 1000 mg/kg. The horizontal distribution of DNTs in the site showed a migration trend to the east and south of evaporation, which was consistent with the terrain of high northwest and low southeast of the site. Due to the high water solubility of pollutants, water flow is the main driving force for the horizontal distribution of DNTs. In the vertical direction, the concentration of pollutants gradually increased with the depth of the soil. DNTs are mainly adsorbed in the third layer (6.0-8.0 m). It can be seen that the accumulation of the 2,4-DNTs-3-SO3- is obviously larger than that of the 2,4-DNTs-5-SO3-, which may be related to the steric hindrance effect of sulfonic acid groups in the two isomers. Results showed DNTs distribution strongly linked to soil physicochemical properties and the migration of DNTs in soil exhibited obvious heterogeneity in time and space. The carcinogenic risks in surface soil (0-1.5 m) and lower soil (1.5-6.0 m, 6.0-8.0 m) are all higher than 1✕10-6; non-carcinogenic risk surface soil (0-1.5 m) is 4.011✕10, which is greater than 1, indicating that they may cause certain harm to the human body. Meanwhile, this study presented a pioneering investigation for the contamination and geochemical transfer of DNTs.


Assuntos
Poluentes do Solo , Trinitrotolueno , China , Dinitrobenzenos , Humanos , Medição de Risco , Solo , Poluentes do Solo/análise
14.
Mar Environ Res ; 167: 105264, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33725510

RESUMO

Baltic mussels (Mytilus spp.) were exposed to the explosive trinitrotoluene (TNT) for 96 h (0.31-10.0 mg/L) and 21 d (0.31-2.5 mg/L). Bioaccumulation of TNT and its degradation products (2- and 4-ADNT) as well as biological effects ranging from the gene and cellular levels to behaviour were investigated. Although no mortality occurred in the concentration range tested, uptake and metabolism of TNT and responses in antioxidant enzymes and histochemical biomarkers were observed already at the lowest concentrations. The characteristic shell closure behaviour of bivalves at trigger concentrations led to complex exposure patterns and non-linear responses to the exposure concentrations. Conclusively, exposure to TNT exerts biomarker reponses in mussels already at 0.31 mg/L while effects are recorded also after a prolonged exposure although no mortality occurs. Finally, more attention should be paid on shell closure of bivalves in exposure studies since it plays a marked role in definining toxicity threshold levels.


Assuntos
Mytilus , Trinitrotolueno , Poluentes Químicos da Água , Animais , Países Bálticos , Biomarcadores , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
15.
Atherosclerosis ; 322: 8-14, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33706084

RESUMO

BACKGROUND AND AIMS: Despite trial evidence, high intensity statins are underutilized in routine clinical practice. This study sought to assess the individual and joint contributions of the TRS2P score as a measure of residual risk and LDL-C levels to benefits from further LDL-C lowering in the TNT trial. METHODS: A total of 9980 patients were divided into 4 groups based on TRS2P and LDL-C at baseline: median (7.2%, group 4), NNT 78 vs. 14 (p-interaction <0.0001). CONCLUSIONS: Measures of residual risk as well LDL-C identify patients who remain at high risk despite statins with the combination identifying those who derive the greatest benefits from even modest additional LDL-C lowering. Attention to residual risk as well as LDL-C may further help to optimize guideline implementation.


Assuntos
Anticolesterolemiantes , Inibidores de Hidroximetilglutaril-CoA Redutases , Trinitrotolueno , Anticolesterolemiantes/efeitos adversos , Atorvastatina , LDL-Colesterol , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Resultado do Tratamento
16.
J Environ Manage ; 284: 111996, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33535125

RESUMO

The development of efficient strategies for the removal of heavy metal ions from aqueous solutions is rapidly demanded as these contaminants are very toxic and carcinogenic and show detrimental effects on the living creatures. The main focus of the current study is on the preparation and assessment of electrospun adsorptive nanofiber membranes for the removal of toxic Ni(II) and Cu(II) from wastewater in the ultrafiltration process. Hydrothermally synthesized titanate nanotubes (TNT) was modified with thiol functional groups and then directly incorporated to the polyvinyl chloride nanofiber matrices via electrospinning process to fabricate an adsorptive membrane. The as-prepared electrospun nanofiber membranes and the nanoadsorbents were characterized with respect to the physiochemical properties, surface structure and morphology, applying XPS, FTIR, FESEM, EDX and TEM analysis and then, the membranes were evaluated in terms of the removal of the heavy metal ions in a continuous ultrafiltration mode. In adsorptive filtration of the metal ions, the effective factors including nanoadsorbents loading (0.5-1.5 wt%), initial metal ion concentration (60-150 mg/L), feed temperature (~25 °C-45 °C), presence of competing ion and reusability were investigated in the UF system where the membranes containing 1.5 wt% thiol-modified TNT and virgin TNT adsorbents demonstrated excellent removal efficiency compared to the other membranes. The Cu(II) and Ni(II) removal efficiency of the membrane containing 1.5 wt% functionalized TNT was 90% and 86.7%, respectively which was the highest ones. As was expected and due to the uniform dispersion and less aggregation of the modified TNT adsorbents on the large surface area of the electrospun nanofibers, more adsorption capacity of the nanoparticles can be exploited. Moreover, the strong affinity of the thiol functional groups toward the metal cations, these membranes removed metal contaminants more efficiently. Besides, the Cu(II) removal efficiency of the fabricated membranes didn't show any drastic changes in the presence of the competing ions. Furthermore, acceptable performance was achieved for the prepared membranes even after four adsorption/regeneration cycles in the continuous UF experiments, demonstrating the feasibility and effectiveness of the prepared adsorptive nanofiber membranes for the removal of heavy metal ions.


Assuntos
Metais Pesados , Nanofibras , Nanotubos , Trinitrotolueno , Poluentes Químicos da Água , Purificação da Água , Adsorção , Íons , Cloreto de Polivinila , Compostos de Sulfidrila , Poluentes Químicos da Água/análise
17.
18.
Environ Monit Assess ; 193(2): 80, 2021 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-33486600

RESUMO

2,4,6-trinitrotoluene or TNT, a commonly used explosive, can pollute soil and groundwater. Conventional remediation practices for the TNT-contaminated sites are neither eco-friendly nor cost-effective. However, exploring bacteria to biodegrade TNT into environment-friendly compound(s) is an interesting area to explore. In this study, an indigenous bacterium, Pseudarthrobacter chlorophenolicus, strain S5-TSA-26, isolated from explosive contaminated soil, was investigated for potential aerobic degradation of TNT for the first time. The isolated strain of P. chlorophenolicus was incubated in a minimal salt medium (MSM) containing 120 mg/L TNT for 25 days at specified conditions. TNT degradation pattern by the bacterium was monitored at regular interval using UV-Vis spectrophotometry, high-performance liquid chromatography, and liquid chromatography mass spectrophotometric, by estimating nitrate, nitrite, and ammonium ion concentration and other metabolites such as 2,4-dinitrotoluene (DNT), 2-amino-4,6-dinitrotoluene (2-ADNT), and 2,4-diamino-6-nitrotoluene (2-DANT). It was observed that, in the presence of TNT, there was no reduction in growth of the bacterium although it multiplied well in the presence of TNT along with no considerable morphological changes. Furthermore, it was found that TNT degraded completely within 15 days of incubation. Thus, from this study, it may be concluded that the bacterium has the potential for degrading TNT completely with the production of non-toxic by-products and might be an important bacterium for treating TNT (i.e., a nitro-aromatic compound)-contaminated sites.


Assuntos
Substâncias Explosivas , Micrococcaceae , Trinitrotolueno , Biodegradação Ambiental , Monitoramento Ambiental
19.
Chemosphere ; 270: 129280, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33418226

RESUMO

The aim of this study was to reveal the biodegradation characteristics and physiological response mechanism of a newly isolated bacterium to 2,4,6-trinitrotoluene (TNT) contamination. A Klebsiella variicola strain with high efficiency of TNT degradation was used as the test strain to analyze the changes in cell growth, morphology, and functional groups under different TNT concentrations (0, 100 mg⋅L-1) and the effects of TNT stress on the metabolic profile as revealed by non-targeted metabonomics. A TNT concentration of 100 mg L-1 caused a significant increase in the 5-day biochemical oxygen demand (BOD5) to 950 mg L-1, while the degradation rate of TNT reached 100% within 30 h after inoculation with Klebsiella variicola. Fourier transform infrared spectroscopy (FTIR) analysis showed changes in the characteristic peak of triamide by TNT treatment. Non-targeted metabonomics identified a total of 544 differentially produced metabolites under TNT treatment (252 upregulated and 292 downregulated), mainly lipids and lipid-like molecules. The metabolic pathways associated with amino acid biosynthesis and metabolism were the most significantly enriched pathways, and simultaneous detection showed that TNT was degraded to 4-amino-2,6-dinitrotoluene (DNT), 2-hydroxylamino-4,6-DNT, 2-amino-4,6-DNT, 2-amino-4-nitrotoluene, and 2,4-DNT. These results confirmed that Klebsiella variicola has a high tolerance to TNT and efficiently degrades it. The degradation mechanism involves TNT-induced accelerated amino acid biosynthesis, production of a protease to catalyze the TNT transformation, and the participation of the transformed TNT products in cell metabolism.


Assuntos
Trinitrotolueno , Biodegradação Ambiental , Dinitrobenzenos , Klebsiella , Trinitrotolueno/toxicidade
20.
Ann Oncol ; 32(1): 58-65, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33098992

RESUMO

BACKGROUND: In the TNT trial of triple negative breast cancer (NCT00532727), germline BRCA1/2 mutations were present in 28% of carboplatin responders. We assessed quantitative measures of structural chromosomal instability (CIN) to identify a wider patient subgroup within TNT with preferential benefit from carboplatin over docetaxel. PATIENTS AND METHODS: Copy number aberrations (CNAs) were established from 135 formalin-fixed paraffin-embedded primary carcinomas using Illumina OmniExpress SNP-arrays. Seven published [allelic imbalanced CNA (AiCNA); allelic balanced CNA (AbCNA); copy number neutral loss of heterozygosity (CnLOH); number of telomeric allelic imbalances (NtAI); BRCA1-like status; percentage of genome altered (PGA); homologous recombination deficiency (HRD) scores] and two novel [Shannon diversity index (SI); high-level amplifications (HLAMP)] CIN-measurements were derived. HLAMP was defined based on the presence of at least one of the top 5% amplified cytobands located on 1q, 8q and 10p. Continuous CIN-measurements were divided into tertiles. All nine CIN-measurements were used to analyse objective response rate (ORR) and progression-free survival (PFS). RESULTS: Patients with tumours without HLAMP had a numerically higher ORR and significantly longer PFS in the carboplatin (C) than in the docetaxel (D) arm [56% (C) versus 29% (D), PHLAMP,quiet = 0.085; PFS 6.1 months (C) versus 4.1 months (D), Pinteraction/HLAMP = 0.047]. In the carboplatin arm, patients with tumours showing intermediate telomeric NtAI and AiCNA had higher ORR [54% (C) versus 20% (D), PNtAI,intermediate = 0.03; 62% (C) versus 33% (D), PAiCNA,intermediate = 0.076]. Patients with high AiCNA and PGA had shorter PFS in the carboplatin arm [3.4 months (high) versus 5.7 months (low/intermediate); and 3.8 months (high) versus 5.6 months (low/intermediate), respectively; Pinteraction/AiCNA = 0.027, Padj.interaction/AiCNA = 0.125 and Pinteraction/PGA = 0.053, Padj.interaction/PGA = 0.176], whilst no difference was observed in the docetaxel arm. CONCLUSIONS: Patients with tumours lacking HLAMP and demonstrating intermediate CIN-measurements formed a subgroup benefitting from carboplatin relative to docetaxel treatment within the TNT trial. This suggests a complex and paradoxical relationship between the extent of genomic instability in primary tumours and treatment response in the metastatic setting.


Assuntos
Trinitrotolueno , Neoplasias de Mama Triplo Negativas , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores , Carboplatina/uso terapêutico , Instabilidade Cromossômica/genética , Humanos , Fenótipo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética
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