Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23.077
Filtrar
1.
Waste Manag ; 125: 154-162, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33706254

RESUMEN

In a circular economy context, there is a growing need for more sustainable waste management options to recover elements from end-of-life materials. These "secondary ores" represent a source of critical elements that are often present in higher concentration compared to their primary ore. In this work, the recovery of lanthanum (La) from waste nickel metal hydride battery (NiMH) leachate is investigated using an aqueous biphasic system (ABS) process based on a pluronic triblock copolymer (L35). An initial screening is performed to determine the influence of the ABS phase forming salt anion and alizarin red extractant on the La extraction efficiency and selectivity. From these results, a three-step ABS process is developed, varying only the nature of the salt and requiring no additional extractant. In a first step, the ABS composed of L35 + thiocyanate ammoniun + H2O efficiently extracts iron, manganese, and cobalt leaving La, cerium, and Ni in solution. Nickel is subsequently recovered by precipitation using dimethylglyoxime. Finally, La is separated from cerium using the L35 + ammonium nitrate + H2O ABS, recovering 62 g of La with 94% purity per kilogram of black mass of NiMH battery. This work highlights the applicability of ABS for the treatment of raw and complex matrices, potentially allowing for a greener hydrometallurgical treatment of wastes.


Asunto(s)
Cerio , Níquel , Suministros de Energía Eléctrica , Lantano , Metales
2.
Bull Environ Contam Toxicol ; 106(4): 658-664, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33710387

RESUMEN

Concentrations of copper (Cu), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn) in muscle and gills of four Benthic fish species (Brachirus orientalis, Argyrops spinifer, Platycephalus indicus and Sillago sihama) from Shif Island of Iran were analyzed using flame atomic absorption spectrometry. The heavy metal levels observed in tissues varied for Cu: 2.15-820.98, Fe: 24.46-533.26, Mn: 1.80-53.17, Ni: 1.86-65.54 and Zn: 28.77-375.79 mg/kg. Significant differences were found among muscle and gill of the four fish species. Heavy metals concentration were significantly (p < 0.05) higher in the gill than in the muscles of all fish species studied. The metal levels in benthic fish species should be continuously monitored in polluted areas since benthic fish indicated a tendency to bioaccumulate pollutants in their tissues from polluted water. The indices of Estimated Daily Intake, Target Hazard Quotient and Hazard Index suggests no risk while carcinogenic risk for Ni showed unacceptable carcinogenic risk.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Animales , Cobre/análisis , Monitoreo del Ambiente , Branquias/química , Irán , Hierro/análisis , Islas , Magnesio , Metales Pesados/análisis , Metales Pesados/toxicidad , Músculos/química , Níquel/análisis , Níquel/toxicidad , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad , Zinc/análisis
3.
Nat Commun ; 12(1): 1868, 2021 03 25.
Artículo en Inglés | MEDLINE | ID: mdl-33767166

RESUMEN

It is very attractive yet underexplored to synthesize heterocyclic moieties pertaining to biologically active molecules from biomass-based starting compounds. Herein, we report an electrocatalytic Achmatowicz reaction for the synthesis of hydropyranones from furfuryl alcohols, which can be readily produced from biomass-derived and industrially available furfural. Taking advantage of photo-induced polymerization of a bipyridyl ligand, we demonstrate the facile preparation of a heterogenized nickel electrocatalyst, which effectively drives the Achmatowicz reaction electrochemically. A suite of characterization techniques and density functional theory computations were performed to aid the understanding of the reaction mechanism. It is rationalized that the unsaturated coordination sphere of nickel sites in our electrocatalyst plays an important role at low applied potential, not only allowing the intimate interaction between the nickel center and furfuryl alcohol but also enabling the transfer of hydroxide from nickel to the bound furfuryl alcohol.


Asunto(s)
Técnicas Electroquímicas/métodos , Furanos/química , 2,2'-Dipiridil/química , Biomasa , Catálisis , Níquel/química
4.
Sci Total Environ ; 771: 144979, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33736143

RESUMEN

The elution of lead, and nickel from water supply devices into water is a potential health concern. This study was performed to examine the actual concentrations of nickel and lead in the water from taps in homes and offices, focusing on the differences between first flush and fully flushed water. The water quality management target value and water quality standard in Japan specify nickel and lead concentrations in drinking water <20 and <10 µg/L, respectively. Nickel concentration in the first flush water (100 mL) from 110 household taps revealed 22 cases (20%) > 20 µg/L, while the fully flushed water satisfied the standard after running 5000 mL of water. The nickel concentration decreased gradually in sequential sampling of each 100 mL from the taps. Lead concentration in the first flush water exceeded the standard in 32 cases (29%), while the fully flushed water was below the target value. The concentration in the first flush water tended to decrease with time since the tap installation, and this was significant after 10 years for nickel but not significant for lead. It is important to flush retained water out of the tap after several hours without use. No significant correlation was found with the volume of the test faucet in the market, but bronze-based products showed higher nickel concentrations than brass and plastic products.


Asunto(s)
Agua Potable , Contaminantes Químicos del Agua , Agua Potable/análisis , Japón , Plomo/análisis , Níquel , Contaminantes Químicos del Agua/análisis , Abastecimiento de Agua
5.
Chemosphere ; 271: 129735, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33736223

RESUMEN

Heavy metals pose a serious threat if they go beyond permissible limits in our bodies. Much heavy metal's viz. Lead, Chromium, Arsenic, Mercury, Nickel, and Cadmium pose a serious threat when they go beyond permissible limits and cause hepatotoxicity. They cause the generation of ROS which in turn causes numerous injuries and undesirable changes in the liver. Epidemiological studies have shown an increase in the levels of such heavy metals in the environment posing a serious threat to human health. Epigenetic alterations have been seen in the event of exposure to such heavy metals. Apoptosis, caspase activation as well as ultrastructural changes in the hepatocytes have also been seen due to heavy metals. Inflammation involving TNF-alpha, pro-inflammatory cytokines, MAPK, ERK pathways have been seen in the event of heavy metal hepatotoxicity. All these have shown that these heavy metals pose a serious threat to human health in particular and the environment as a whole.


Asunto(s)
Arsénico , Enfermedad Hepática Inducida por Sustancias y Drogas , Mercurio , Metales Pesados , Arsénico/toxicidad , Cadmio/toxicidad , Cromo , Humanos , Plomo , Mercurio/toxicidad , Metales Pesados/toxicidad , Níquel/toxicidad
6.
Sci Total Environ ; 768: 144666, 2021 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-33736318

RESUMEN

The role of endophytic fungi isolated from different populations of European Ni hyperaccumulators was investigated in regard to the microorganisms' ability to enhance the hyperaccumulation of Ni in Noccaea caerulescens. Effects of particular species of endophytic fungi on adaptation of N. caerulescens to excess Ni were tested by co-cultivation with single strains of the fungi. Seven of these had a positive effect on plant biomass production, whereas two of the tested species inhibited plant growth; biomass production of inoculated plants was significantly different compared to non-inoculated control. Inoculation with six fungal strains: Embellisia thlaspis, Pyrenochaeta cava, Phomopsis columnaris, Plectosphaerella cucumerina, Cladosporium cladosporioides and Alternaria sp. stimulated the plant to uptake and accumulate more Ni in both roots and shoots, compared to non-inoculated control. P. columnaris was isolated from all plant species sampled. Strains isolated from Noccaea caerulescens and Noccaea goesingensis increased Ni root and shoot accumulation of their native hosts (compared to non-inoculated control). Inoculation of different populations of Noccaea with P. columnaris of foreign origin did not cause its host to accumulate more Ni, with the exception of the Ni-unadapted ecotype of N. goesingensis. Inoculation with P. columnaris from N. caerulescens significantly improved Ni uptake, but the effect of the fungus was not as prominent as in the case of N. caerulescens. By comparing the transcriptomes of N. caerulescens and N. goesingensis from Flatz inoculated with P. columnaris, we showed that enhanced uptake and accumulation of Ni in the plants is accompanied by an upregulation of several genes mainly involved in plant stress protection and metal uptake and compartmentation.


Asunto(s)
Brassicaceae , Níquel , Ascomicetos , Cladosporium , Hongos
7.
Carbohydr Polym ; 260: 117840, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712175

RESUMEN

Highly efficient shielding materials with an excellent electromagnetic wave absorption have gained increased attention. A new design was used to provide cellulose paper with a high electromagnetic shielding effectiveness (EMI SE) and improve the absorption performance by constructing an asymmetry sandwich structure that consisted of a dense nickel coating, Fe3O4 nanoparticles and a porous nickel layer. This unique structure caused a "multiple reflection-absorb-reflection" process when the electromagnetic waves penetrated the sample. The EMI absorption (SEA) and total SE (SET) increased with Fe3O4 absorption time increasing at 8.2-12.4 GHz, which was attributed to the synergistic effect between porous nickel layer and Fe3O4 nanoparticles. The SEA and SET of the sample with a thickness of 0.195 mm can achieved 18.57 and 41.88 dB, respectively. The design was conducive to improving the magnetic and corrosion resistance properties. This study provided a novel path to obtain a low cost and lightweight electromagnetic shielding material that can reduce secondary radiation.


Asunto(s)
Celulosa/química , Óxido Ferrosoférrico/química , Níquel/química , Protectores contra Radiación/química , Conductividad Eléctrica , Campos Electromagnéticos , Magnetismo , Nanopartículas del Metal/química , Porosidad , Propiedades de Superficie , Temperatura
8.
Nanotoxicology ; 15(2): 276-288, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33554687

RESUMEN

The combination effect of co-exposed different types of nanomaterials is little known although humans are generally exposed to a mixture of nanomaterials from urban ultrafine particles or industrial nanomaterials. Herein, we evaluated the combined effect of nanoparticles (NPs) using three types of NPs in different inflammogenic categories: carbon black (CB), nickel oxide (NiO), and copper oxide (CuO). A single type of NPs or NPs in combination was intratracheally instilled into the lungs of rats and the bronchoalveolar lavage fluid (BALF) was analyzed at 24 h after instillation to evaluate the acute inflammogenic potential. The percentage of neutrophils in BALF was selected as a toxicity endpoint and the potential for reactive oxygen species (ROS) generation, dose-response of the combined effect, sequential treatment of CB and NiO, and uptake of NiO to alveolar macrophages after combined treatment of CB and NiO were evaluated for the mechanism of the combined effect. Co-exposure of CuO and NiO showed an additive effect on the percentage of neutrophils and ROS generation potential, which implies that the physicochemical properties of each NP are not influenced by the other type. While CB exerted an antagonistic effect on the percentage of neutrophils in combined treatment with CuO or NiO. The antagonistic effect of CB was due to the scavenging activity of the ROS generated by the CuO and NiO rather than the competition in cellular uptake to target cells (i.e. alveolar macrophages), which highlight the importance of the combined effect of NPs in the risk assessment.


Asunto(s)
Cobre/toxicidad , Pulmón/efectos de los fármacos , Nanopartículas/toxicidad , Níquel/toxicidad , Hollín/toxicidad , Animales , Líquido del Lavado Bronquioalveolar/citología , Líquido del Lavado Bronquioalveolar/inmunología , Citocinas/inmunología , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Pulmón/inmunología , Macrófagos Alveolares/efectos de los fármacos , Masculino , Neutrófilos/citología , Neutrófilos/efectos de los fármacos , Tamaño de la Partícula , Ratas , Ratas Wistar , Propiedades de Superficie , Tráquea/efectos de los fármacos
9.
Ecotoxicol Environ Saf ; 213: 112031, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33578097

RESUMEN

BACKGROUND: Nickel is a component of biomedical alloys that is released during corrosion or friction and causes cytotoxicity, mutation, differentiation or even carcinogenesis in tissues. However, the mechanisms underlying the potential hazards of Nickel-containing alloys implanted in the human body by surgery remain uncertain. OBJECTIVE: To study the effect of Ni(II) (NiCl2•6H2O) on cancer cells. METHODS: A549 and RKO cells were treated with various concentrations of Ni(II) to determine the effect of Ni(II) on cellular viability using a CCK8 assay. Flow cytometry was performed to analyze the effect of Ni(II) on apoptosis and the cell cycle. Sphere-forming assays were conducted to examine the stemness properties of A549 and RKO cells. Western blotting was to evaluate the expression levels of SOX2, IDH1, HIF-1ɑ and ß-catenin. The expression of isocitrate dehydrogenase (IDH1) in rectum adenocarcinoma (READ) was analyzed by Gene Expression Profiling Interactive Analysis (GEPIA). Kaplan-Meier analysis was used to calculate the correlation between survival and IDH1 expression. RESULTS: Long-term exposure (120 days) to 100 µM Ni(II) significantly repressed cell proliferation, decreased colony formation and arrested the cell cycle at the G0/G1 phase. In addition, the stem-like traits of A549 and RKO cells were significantly augmented. Ni(II) also significantly decreased the protein expression of IDH1 and the synthesis rate of NAPDH, which competitively inhibited α-ketoglutarate (α-KG) generation. The downregulation of IDH1 not only promoted ß-catenin accumulation in the cell nucleus in a HIF-1ɑ signaling-dependent manner but also induced the expression of the transcription factor SOX2 to maintain the stemness properties of cancer cells. Moreover, IDH1 expression negatively correlated with the clinicopathologic characteristics of READ. CONCLUSION: These findings demonstrate that chronic and continuous release of Ni(II) to the microenvironment suppresses IDH1 expression and augments the stemness properties of cancer cells via the activation HIF-1ɑ/ß-catenin/SOX2 pathway to enhance local tumor recurrence in patients with implanted Nickel-containing alloys at surgical sites.


Asunto(s)
Isocitrato Deshidrogenasa/metabolismo , Níquel/toxicidad , Apoptosis , Diferenciación Celular , Línea Celular Tumoral , Proliferación Celular/genética , Supervivencia Celular/efectos de los fármacos , Humanos , Mutación , Neoplasias , Transducción de Señal , beta Catenina
10.
Ecotoxicol Environ Saf ; 213: 112034, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33581486

RESUMEN

BACKGROUND: Nickel, as one of the most abundant elements in the earth's crust, plays many roles in human reproduction and life. It is an essential trace element for the human body, but can be harmful in excess amounts. Nickel has a significant impact on endocrine hormones in humans and animals, potentially causing abnormal secretions and changing the structure and function of endocrine organs. This article systematically reviews the effects of nickel on hormone secretion and target organs in the endocrine system and identifies areas of insufficient research. METHODS: All data in this article were extracted from peer-reviewed articles. The PubMed, SciFinder, Google Scholar, Web of Science, and China National Knowledge Infrastructure databases were searched for relevant articles. Data on nickel's effect on endocrine system hormones and target organs were retrieved, and manually sorted prior to inclusion in this review. RESULTS: Nickel acts on the endocrine system and affects the release and regulation of endocrine hormones. Disorders of endocrine hormones may lead to retardation of human growth and mental development, disturbance of water and salt regulation, and even a decline in reproductive ability. Nickel affects the hypothalamus and pituitary gland by regulating organs upstream of the endocrine axis; it can cause abnormal secretion of pituitary hormones, which affects target organs of the endocrine axis, resulting in dysfunction therein and abnormal secretion of related hormones. Nickel also damages target organs, mainly by inducing apoptosis, which triggers oxidative stress, cell autophagy, free radical release, and DNA damage. However, there are few studies on the endocrine axis, and some of the data are contradictory. Nevertheless, it is clear that nickel affects the endocrine system. CONCLUSIONS: Nickel can damage organs in the endocrine system, such as the hypothalamus and pituitary. It also affects the secretion of hormones and damages the target organs of these hormones; this can result in endocrine system dysfunction. However, the results have been equivocal and further research is needed.


Asunto(s)
Sistema Endocrino/metabolismo , Hormonas/metabolismo , Níquel/toxicidad , Animales , China , Humanos , Hipotálamo , Hipófisis , Reproducción
11.
Bioresour Technol ; 329: 124853, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33621929

RESUMEN

In this work, nickel ferrite nanoparticles (NiFe2O4 NPs) was prepared to improve hydrogen (H2) production by dark fermentation. Moderate amounts (50-200 mg/L) promoted H2 generation, while excess NiFe2O4 NPs (over 400 mg/L) lowered H2 productivity. The highest H2 yields of 222 and 130 mL/g glucose were obtained in the 100 mg/L (37 °C) and 200 mg/L NiFe2O4 NPs (55 °C) groups, respectively, and the values were 38.6% and 28.3% higher than those in the control groups (37 °C and 55 °C). Soluble metabolites showed that NiFe2O4 NPs enhanced the butyrate pathway, corresponding to the increased abundance of Clostridium butyricum in mesophilic fermentation. The endocytosis of NiFe2O4 NPs indicated that the released iron and nickel favored ferredoxin and hydrogenase synthesis and activity and that NiFe2O4 NPs could act as carriers in intracellular electron transfer. The NPs also optimized microbial community structure and increased the levels of extracellular polymeric substances, leading to increased H2 production.


Asunto(s)
Nanopartículas , Níquel , Suplementos Dietéticos , Fermentación , Compuestos Férricos , Hidrógeno
12.
J Environ Manage ; 284: 112024, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33548751

RESUMEN

The presence of moderate concentrations of impurities in the nickel-plating baths generates failures on the coated pieces. This situation entails the necessity of replacing the electroplating bath, which implies the generation of large volumes of wastewater with metallic species and high quantity of sludge. For this reason, the adsorption of the principal impurities of nickel-plating baths of an industry was analyzed in this work. Particularly, the removal of Zn2+ was studied in more detail since the presence of this metal in the baths generates black spots on the coated pieces. Different commercial materials were used as adsorbents and Zn2+ adsorption studies were carried out using both standard solutions and industrial water from the nickel-plating baths. All the adsorption tests were performed in batch systems under constant agitation and the quantification of the impurities was made by ICP-MS analysis. The bone char (BC) was an efficient adsorbent for the removal of the principal impurities of nickel-plating baths. The use of molecular simulation tools helped to understand the preferences of the hydroxyapatite (the principal component of bone char) for different metallic ions present in the industrial waters. According to both the experimental adsorption and molecular simulation results, hydroxyl and phosphate groups of bone char are responsible of the adsorption of impurities of nickel-plating baths.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Adsorción , Baños , Galvanoplastia , Níquel/análisis , Contaminantes Químicos del Agua/análisis
13.
Environ Pollut ; 275: 116556, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33588191

RESUMEN

The public around the world is increasingly concerned about male reproductive health. The impact of nickel nanoparticles (Ni NPs) on male reproductive toxicity including sperm production, motility and fertilizing capacity has been confirmed by our previous researches. In the current study of Ni NPs-inducing toxicity, the expression profiles of piRNAs and their predicted target genes associated with male infertility, were obtained. The results showed that piR-mmu-32362259 was the highest differential expression multiples in both the testis tissues of male mice and GC-1 cells similarly. Notably, piR-mmu-32362259 target gene was significantly enriched in the PI3K-AKT signaling pathway. All these results suggest that piR-mmu-32362259 may affect the occurrence and development of injury in the mouse spermatogenesis process by regulating the PI3K-AKT signaling pathway. In order to verify the result, piR-mmu-32362259 low-expression lentivirus was used to transfect GC-1 cells to establish a stable transfected cell model. The effects of piR-mmu-32362259 on the viability, cycle and apoptosis as well as related protein expression levels of GC-1 cells induced by Ni NPs were detected using CCK8, flow cytometry and western blot assay, respectively. The results showed that low expression of piR-mmu-32362259 could not only alleviate the decrease of GC-1 cell viability, affect the cell cycle and reduce the apoptosis rate, but also significantly affect the expression levels of key proteins and their downstream molecules of PI3K/AKT/mTOR signaling pathway. Collectively, our current results provide a theoretical basis for further exploring the molecular regulatory mechanism of male reproductive toxicity induced by Ni NPs.


Asunto(s)
Nanopartículas , Níquel , Acetatos , Animales , Apoptosis , Expresión Génica , Masculino , Ratones , Níquel/toxicidad , Fenoles , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt
14.
Medicine (Baltimore) ; 100(3): e23865, 2021 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-33545953

RESUMEN

ABSTRACT: To study the effect of continuous irrigation of rotating nickel-titanium instrument with several common clinical fluids on the diameter, breaking length and breaking position of nickel-titanium instrument, so as to provide some reference and theoretical basis for clinical operation and instrument improvement.A standardized curved root canal model was established, and ProTaper Universal (PTU) F1 instrument was selected for root canal preparation. The nickel-titanium F1 instrument was flushed with distilled water, 0.9% NaCl, 0.2% chlorhexidine, 1% sodium hypochlorite and 5% sodium hypochlorite, and the diameter, length and position of the instrument before and after breakage were recorded.Only 5% sodium hypochlorite influenced the diameter of 6 mm marker points under different irrigation conditions (P < .05). There was no statistical difference in the length of broken instruments among all the groups, and torsional deformation mainly occurred at the end of broken instruments. The broken positions of instruments in all the groups were located at the bending segment of the root canal. The breaking frequency of the 5% sodium hypochlorite group was the highest in the area 3-5.5 mm away from apical foramen, while the other 4 groups had the highest breaking frequency in the area 0 to 1.5 mm away from apical foramen.External irrigation with different fluids did not influence the breaking length of instruments. The closer to the apical foramen was, the higher the breaking frequency of instruments was. However, only 5% sodium hypochlorite can affect the diameter of rotary nickel-titanium instruments, and may lead to early breakage of the instrument, indicating that the use of disinfectants, except 5% sodium hypochlorite, cannot reduce breakage resistance of nickel-titanium instrument compared with distilled water flushing. Furthermore, 5% hypochlorite could not be recommended for irrigation in clinical practice.


Asunto(s)
Preparación del Conducto Radicular/instrumentación , Materiales Biomédicos y Dentales , Clorhexidina , Diseño de Equipo , Falla de Equipo , Humanos , Níquel , Solución Salina , Hipoclorito de Sodio , Irrigación Terapéutica , Titanio
15.
Ecotoxicol Environ Saf ; 212: 111986, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33540338

RESUMEN

Population exposure to environmental contaminants can be precisely observed through human biomonitoring studies. The present study aimed to systematically review all the biomonitoring studies conducted in Iran on some selected carcinogen environmental pollutants. In this systematic review study, 11 carcinogen agents were selected including arsenic, cadmium, chromium, nickel, lindane, benzene, trichloroethylene (TCE), pentachlorophenol (PCP), radon-222, radium-224, - 226, - 228, and tobacco smoke. The Web of Science, PubMed, and Scopus databases were searched for peer-reviewed articles published in English. After several screening steps, data were extracted from the studies. Meta-analyses (a random-effect model using the DerSimonian-Laired method) were performed only for the biomarkers with more than three eligible articles, including cadmium in blood and breast milk, and arsenic in breast milk. Methodological quality of the studies was assessed using the Newcastle-Ottawa Quality Assessment Scale adapted for cross-sectional studies. Of the 610 articles found in the database search, 30 studies were eligible for qualitative review, and 13 were included in the meta-analysis (cadmium in blood (n = 3), cadmium in breast milk (n = 6), and arsenic in breast milk (n = 4)). The overall pooled average concentrations (95% CI) of cadmium in blood, cadmium in breast milk, and arsenic in breast milk were 0.11 (95% CI: 0.08, 0.14), 5.38 (95% CI: 3.60, 6.96), and 1.42 (95% CI: 1.02, 1.81) µg/L, respectively. These values were compared with the biomarker concentrations in other countries and health-based guideline values. This study showed that there is a need for comprehensive action plans to reduce the exposure of general population to these environmental contaminants.


Asunto(s)
Monitoreo Biológico , Contaminantes Ambientales/análisis , Arsénico/análisis , Cadmio/análisis , Cromo/análisis , Estudios Transversales , Exposición a Riesgos Ambientales/análisis , Contaminación Ambiental/análisis , Femenino , Humanos , Irán , Leche Humana/química , Níquel/análisis
16.
Niger J Clin Pract ; 24(2): 247-253, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33605916

RESUMEN

Aims: To evaluate the effect of multiple-use and sterilization on cyclic fatigue and shaping ability of heat-treated nickel-titanium (NiTi) rotary instruments. Methods: A total of 120 acrylic blocks with S-shaped canals were photographed and prepared by HyFlex CM, ProTaper Next, and Twisted File. Ten new sets of each rotary instruments were used for four times. The autoclaving process was repeated after each use. Pre- and post instrumentation images were superimposed. The amount of resin removal and canal transportation by each system was measured in eleven different points. Instruments were subsequently subjected to a cyclic fatigue test in a double-curved artificial canal. The means and standard deviations of the number of cycles to failure (NCF) were calculated and statistically analyzed (P < 0.05). Results: No fractures occurred during the shaping of the simulated canals. The ProTaper Next removed the greatest amount of resin, whereas the Twisted File had the lowest values at all levels. Repeated clinical use and sterilization resulted in a decrease in the resin removal at most levels in Twisted File and ProTaper Next. In terms of canal transportation, an increase in a limited number of levels was detected after repeated use of all rotary files. Twisted File had the greatest cyclic fatigue resistance, followed by HyFlex CM and ProTaper Next (P < 0.05). Conclusions: The effects of repeated use and autoclaving on the cyclic fatigue resistance of HyFlex CM, ProTaper Next, and Twisted File were not significant. Canal transportation increased mostly in the apical region. The amount of resin removal decreased as the number of use increased for ProTaper Next and Twisted File instruments.


Asunto(s)
Níquel , Titanio , Instrumentos Dentales , Cavidad Pulpar , Diseño de Equipo , Falla de Equipo , Calor , Humanos , Ensayo de Materiales , Preparación del Conducto Radicular
17.
Food Chem ; 349: 129202, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33582540

RESUMEN

In this work, we propose a electrochemical enzyme-free glucose sensor by direct growth of conductive Ni/Co bimetal MOF on carbon cloth [Ni/Co(HHTP)MOF/CC] via a facile hydrothermal method. Due to excellent conductivity between Ni/Co(HHTP)MOF and CC, synergic catalytic effect of Ni and Co elements, the Ni/Co(HHTP)MOF/CC not only provides larger surface area and more effective active sites, but also boosts the charge transports and electro-catalytic performance. Under optimized conditions, the Ni/Co(HHTP)MOF/CC shows excellent activity with a linear range of 0.3 µM-2.312 mM, a low detection limit of 100 nM (S/N = 3), a fast response time of 2 s and a high sensitivity of 3250 µA mM-1 cm-2. Furthermore, the Ni/Co(HHTP)MOF/CC was successfully applied for the detection of glucose in real serum and beverages with competitive performances. This facile and cost-effective method provides a novel strategy for monitoring of glucose in biological and food samples.


Asunto(s)
Bebidas/análisis , Carbono/química , Cobalto/química , Electroquímica/instrumentación , Glucosa/análisis , Estructuras Metalorgánicas/química , Níquel/química , Glucemia/análisis , Catálisis , Conductividad Eléctrica , Humanos , Límite de Detección
18.
Int J Mol Sci ; 22(1)2021 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-33401533

RESUMEN

Rats were exposed to nickel oxide nano-aerosol at a concentration of 2.4 ± 0.4 µg/m3 in a "nose only" inhalation setup for 4 h at a time, 5 times a week, during an overall period of 2 weeks to 6 months. Based on the majority of the effects assessed, this kind of exposure may be considered as close to LOAEL (lowest observed adverse effect level), or even to NOAEL (no observed adverse effect level). At the same time, the experiment revealed genotoxic and allergic effects as early as in the first weeks of exposure, suggesting that these effects may have no threshold at all.


Asunto(s)
Exposición por Inhalación/efectos adversos , Pulmón/patología , Nanopartículas/toxicidad , Níquel/toxicidad , Medición de Riesgo/métodos , Animales , Femenino , Pulmón/efectos de los fármacos , Nivel sin Efectos Adversos Observados , Ratas
19.
Environ Sci Pollut Res Int ; 28(14): 17146-17157, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33394442

RESUMEN

The natural abundance of Cr and Ni in serpentine soils is well-known, but the food safety of rice grown in these hazardous paddy soils is poorly understood. The study evaluated the bioaccumulation of chromium (Cr) and nickel (Ni) in rice (Oryza sativa) grown in serpentine-derived paddy soils in the Philippines. Surface soil (0-20 cm) samples were collected and characterized across three (i.e., Masinloc, Candelaria, and Sta. Cruz) paddy areas in Luzon Island, Philippines. At least 3 to 4 whole rice plants at mature stage were uprooted manually in each sampling point where the soil samples were collected. The total Cr and Ni concentrations in rice (i.e., roots, shoots, and grains) and soil, soil physicochemical properties, bioaccumulation factor (BAF), translocation factor (TF), and the hazard quotients (HQ) were determined. Results revealed that Cr and Ni in rice were accumulated mostly in the roots. Although paddy soils had elevated total Cr and Ni concentrations, the BAF and soil-to-root TF values for Cr and Ni were < 1. In terms of human health risks, results further revealed low risk for both male and female Filipino adults as HQ values for Cr and Ni were < 1. While it is safe to consume rice grown in the area in terms of Cr and Ni dietary intake, more studies are necessary to understand the dynamics and bioavailability of these heavy metals in other crops and drinking water from tube wells in these areas in order to provide a more holistic human health-based assessments and to ensure consumer safety in serpentine areas. In addition, a more reliable data on Cr and Ni speciation in serpentine soils and crops is critically important. Further studies are also needed to understand the contribution of bioavailable heavy metals in improving the soil health to achieve food safety.


Asunto(s)
Metales Pesados , Oryza , Contaminantes del Suelo , Bioacumulación , Cromo , Femenino , Humanos , Masculino , Metales Pesados/análisis , Níquel , Filipinas , Medición de Riesgo , Suelo , Contaminantes del Suelo/análisis
20.
Chemosphere ; 271: 129573, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33460891

RESUMEN

Unscientific municipal solid waste (MSW) dumping provokes heavy metal (HM) associated ecological and human health hazards through heightened bioavailability and bioaccumulation. In this study, we focused on three important HMs Cadmium (Cd), Copper (Cu) and Nickel (Ni) and their geochemical fractions, to enable clutter free data management, analysis and interpretation. Stratified random soil sampling was carried out from twenty different locations around a Ramsar site (Deepor Beel) in Guwahati, India. The spatial concentration profiles of Cd, Cu and Ni were determined by data elicited from geochemical fractionation and the Geographic Information System (GIS). Ecological and health risks indices were used to evaluate the severity of soil pollution and assess the level of health risks. All the three HMs thus evaluated, conformed to the potential bioavailable category. Cd (54.59%) was associated mostly with the carbonate bound fraction (F3), while 25.53% of Cu and 40.60% Ni were associated with the exchangeable fraction (F2). Significant contamination levels and higher ecological risks posed by these metals were in the order Cd > Ni > Cu. Children were found to be more vulnerable towards Cd associated health risks whereas, Ni posed threats to both adults and children. Cu posed no risk to human health. Geochemical fractionation and different indices played a critical role in the integrated assessment of soil pollution, ecological and health risk assessment, and provided an empirical basis for the sustainable future planning and comprehensive adaptive management practices for MSW.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Adulto , Cadmio/análisis , Niño , Cobre/análisis , Monitoreo del Ambiente , Humanos , India , Metales Pesados/análisis , Níquel/análisis , Medición de Riesgo , Suelo , Contaminantes del Suelo/análisis , Residuos Sólidos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...