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1.
Environ Sci Pollut Res Int ; 30(53): 113205-113217, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37858014

RESUMO

Environmental pollutants are ubiquitous in our environmental media, resulting in detrimental impacts on both humans and the environment. An evidence-based review, particularly a systematic review and meta-analysis, performs a crucial function in assessing the pollution status of pollutants in environmental media at national and global scales. We selected and thoroughly investigated 76 papers focusing on systematic reviews and meta-analyses of contaminants in environmental media. The need to broaden the scope of studies was observed with an increase in the total number of publications, and there were greater focuses on food safety, water pollution, biological pollution, and environmental risks. Furthermore, this review outlined the fundamental procedures involved in a systematic review and meta-analysis, including literature searching, screening of articles, study quality analysis, data extraction and synthesis, and meta-analysis. A meta-analysis typically comprises fixed- and/or random-effects meta-analysis, identifying and measuring heterogeneity, sensitivity analysis, publication bias, subgroup analysis, and meta-regression. We specifically explored the application of meta-analysis to assess the presence of contaminants in environmental media based on two different pollutant categories, namely, non-biological and biological pollutants. The mean value is commonly utilized to assess the pooled concentration of non-biological pollutants, while the prevalence serves as the effect size of biological pollutants. Additionally, we summarized the innovative applications, frequent misuses, and problems encountered in systematic reviews and meta-analyses. Finally, we proposed several suggestions for future research endeavors.


Assuntos
Poluição do Ar , Poluentes Ambientais , Humanos , Poluentes Ambientais/análise , Previsões , Poluição da Água/análise , Inocuidade dos Alimentos , Poluição do Ar/análise
2.
Anal Methods ; 14(47): 4912-4921, 2022 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-36441632

RESUMO

We propose a feature color extraction method that improves the accuracy of water quality analysis using a digital image and eliminates the effect of interfering ions and chromogenic agents on the color after a color reaction. The proposed method is based on color deconvolution (CD) combined with machine learning for substance measurement in water. After an ordinary camera acquires the solution image after color reaction, the CD algorithm is applied to extract the feature image, calculate the first-order, second-order, and third-order color moments corresponding to RGB channels, and construct a gradient boosting regression tree prediction model based on color moment features to detect substances in water. In predicting ammonia, nitrite, and orthophosphate concentrations, the mean square error values were 0.01029, 0.00063, and 0.1361, and the mean absolute error values were 0.08103, 0.02231, and 0.32886, respectively. There was no significant difference in the results of the comparative spectrophotometric method on the actual water samples. The spiked recoveries of the samples ranged from 94% to 120%, confirming that the method can effectively measure the content of substances in water.


Assuntos
Qualidade da Água
3.
World J Clin Cases ; 10(5): 1572-1579, 2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35211594

RESUMO

BACKGROUND: Nodular fasciitis (NF) is a self-limiting tumor that mostly occurs in the subcutaneous superficial fascia. NF originating from the appendicular periosteum is extremely rare. A large NF lesion of periosteal origin can be misdiagnosed as a malignant bone tumor and may cause overtreatment. CASE SUMMARY: A right axillary mass was found in a 46-year-old man and was initially diagnosed intraoperatively as low-grade sarcoma, but later diagnosed as NF after post-resection histopathological evaluation. Furthermore, fluorescence in situ hybridization analysis revealed a USP6 gene rearrangement that confirmed the diagnosis. To the best of our knowledge, this is the first case of NF in the humeral periosteum. CONCLUSION: NF poses a diagnostic challenge as it is often mistaken for sarcoma. Postoperative histopathological examination of whole sections can be combined with immunohistochemical staining and, if necessary, the diagnosis can be confirmed by molecular detection, and thus help avoid overtreatment.

4.
Spectrochim Acta A Mol Biomol Spectrosc ; 252: 119462, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33524823

RESUMO

In this work, we report a novel protein-based nanoprobe (PNP) that can be employed for quantitative analysis of Cu2+ in pure water medium and real samples. Structurally, the proposed nanoprobe comprises a biofriendly protein (hen egg-white lysozyme (HEWL)) and a Cu2+-specific chromogenic agent, where HEWL acts as a nanocarrier encapsulating a structurally tailored rhodamine B derivate. The resulting PNP exhibits a hydrodynamic diameter of ~ 106 nm and efficiently disperses in water, enabling the detection of Cu2+ in pure aqueous systems without the aid of any organic co-solvents. The high sensitivity and selectivity of PNP allow the colorimetric detection of Cu2+ in the presence of other metal interferents with a low detection limit of 160 nM. The satisfying recovery of trace level Cu2+ in environmental samples demonstrate the great potential of employing PNP for the determination of Cu2+ in actual applications. Most importantly, the simple co-grinding method employing proteins and chromogenic agents provides a novel strategy to generate sensing systems that are useful detection of pollutants in aqueous samples.


Assuntos
Colorimetria , Cobre , Nanoestruturas , Proteínas , Limite de Detecção , Metais , Água
5.
Sci Total Environ ; 750: 141545, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182166

RESUMO

Biochar is deemed as the ideal material for the effective removal of heavy metals in wastewater treatment. Herein, we developed a facile one-step solvothermal method for the preparation of sulfonated biochar (SBC) from Axonopus compressus under a low-temperature condition. FTIR and XPS analysis demonstrate that plenty of -OH, -COOH and -SO3H moieties are generated on the surface of SBC during the sulfonation process. Due to high electronegativity and strong complexation of these moieties, SBC can rapidly adsorb Pb(II) and Cd(II) with capacities of 191.07 and 85.76 mg/g respectively within 5 min. SBC can be reused for 5 cycles with a negligible loss of adsorption capacity. In addition, different biomass-based biochars are prepared under the identical experimental conditions, and they are successfully applied in the treatments of Pb(II) and Cd(II). The satisfying results indicate that one-step low-temperature sulfonation could be a universal method, and various types of biomass waste could be the abundant, effective, economical material source for the treatment of environmental heavy metal pollution in future.


Assuntos
Cádmio , Águas Residuárias , Adsorção , Carvão Vegetal , Chumbo
6.
Spectrochim Acta A Mol Biomol Spectrosc ; 241: 118657, 2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-32659703

RESUMO

A rhodamine B-based sensor (RS) was designed and synthesized by a combination of the spirolacton rhodamine B (fluorophore) and multidentate chelates (ionophore) with high affinity towards Hg2+. In the presence of Hg2+, the resulting red-orange fluorescence (under UV light) and naked eye red color of RS are supposed to be used for quantitative and qualitative measurement of Hg2+. Further fluorescent titration and analysis demonstrate that RS can selectively detect Hg2+ within 1 s with a low limit of detection (LOD) of 16 nM in acetonitrile media, meanwhile, the association constant (Ka) was calculated to be 0.32 × 105 M-1. More importantly, the resultant complex (RSHg) of RS and Hg2+ has also been successfully applied to detect limited water content in acetonitrile solution.

7.
Spectrochim Acta A Mol Biomol Spectrosc ; 219: 232-239, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31048252

RESUMO

Hypochlorous acid (HClO) is one of the most important ROS (reactive oxygen species) and common pollutant in tap-water. However, the determination of HClO with fast response and high sensitivity/selectivity is still an urgent demanding. Here we fabricated a ratiometric fluorescent probe RC based on TBET (through-bond energy transfer) on the platform of coumarin and rhodamine with the thiosemicarbazide group as the linker. This probe could display the characteristic fluorescence emission of coumarin. Upon addition of HClO, the linker was reacted into an oxadiazole, resulting in the opening of spiro-ring of rhodamine. The resultant then gives ratiometric fluorogenic changes. The probe exhibits fast response and high selectivity and sensitivity towards HClO with a low limit of detection (~140 nM). Eventually, RC is successfully applicated for determining spiked HClO in water samples and imaging endogenous HClO in living cells.


Assuntos
Cumarínicos/química , Corantes Fluorescentes/química , Ácido Hipocloroso/análise , Rodaminas/química , Animais , Células HeLa , Humanos , Camundongos , Imagem Óptica/métodos , Células RAW 264.7 , Espectrometria de Fluorescência/métodos , Água/análise
8.
Acta Pharmacol Sin ; 37(7): 950-62, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27292614

RESUMO

AIM: Tubeimoside-1 (TBMS1), a triterpenoid saponin extracted from the Chinese herbal medicine Bolbostemma paniculatum (Maxim) Franquet (Cucurbitaceae), has shown anticancer activities in various cancer cell lines. The aim of this study was to investigate the anticancer activity and molecular targets of TBMS1 in human prostate cancer cells in vitro. METHODS: DU145 and P3 human prostate cancer cells were treated with TBMS1. Cell viability and apoptosis were detected. ROS generation, mitochondrial membrane potential and cell cycle profile were examined. Western blotting was used to measure the expression of relevant proteins in the cells. RESULTS: TBMS1 (5-100 µmol/L) significantly suppressed the viability of DU145 and P3 cells with IC50 values of approximately 10 and 20 µmol/L, respectively. Furthermore, TBMS1 dose-dependently induced apoptosis and cell cycle arrest at G0/G1 phase in DU145 and P3 cells. In DU145 cells, TBMS1 induced mitochondrial apoptosis, evidenced by ROS generation, mitochondrial dysfunction, endoplasmic reticulum stress, modulated Bcl-2 family protein and cleaved caspase-3, and activated ASK-1 and its downstream targets p38 and JNK. The G0/G1 phase arrest was linked to increased expression of p53 and p21 and decreased expression of cyclin E and cdk2. Co-treatment with Z-VAD-FMK (pan-caspase inhibitor) could attenuate TBMS1-induced apoptosis but did not prevent G0/G1 arrest. Moreover, co-treatment with NAC (ROS scavenger), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor) or salubrinal (ER stress inhibitor) significantly attenuated TBMS1-induced apoptosis. CONCLUSION: TBMS1 induces oxidative stress-mediated apoptosis in DU145 human prostate cancer cells in vitro via the mitochondrial pathway.


Assuntos
Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Fase G1/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Neoplasias da Próstata/patologia , Fase de Repouso do Ciclo Celular/efeitos dos fármacos , Saponinas/farmacologia , Triterpenos/farmacologia , Acetilcisteína/farmacologia , Clorometilcetonas de Aminoácidos/farmacologia , Antracenos/farmacologia , Caspase 3 , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cinamatos/farmacologia , Ciclina E/metabolismo , Quinase 2 Dependente de Ciclina/metabolismo , Relação Dose-Resposta a Droga , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Humanos , Imidazóis/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , MAP Quinase Quinase Quinase 5/metabolismo , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Piridinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Saponinas/antagonistas & inibidores , Tioureia/análogos & derivados , Tioureia/farmacologia , Triterpenos/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
9.
Anal Chim Acta ; 919: 85-93, 2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27086103

RESUMO

A new colorimetric and fluorogenic probe (RN3) based on rhodamine-B has been successfully designed and synthesized. It displays a selective response to Hg(2+) in the aqueous buffer solution over the other competing metals. Upon addition of Hg(2+), the solution of RN3 exhibits a 'naked eye' observable color change from colorless to red and an intensive fluorescence with about 105-fold enhancement. The changes in the color and fluorescence are ascribed to the ring-opening of spirolactam in rhodamine fluorophore, which is induced by a binding of the constructed receptor to Hg(2+) with the association and dissociation constants of 0.22 × 10(5) M(-1) and 25.2 µM, respectively. The Job's plot experiment determines a 1:1 binding stoichiometry between RN3 and Hg(2+). The resultant "turn-on" fluorescence in buffer solution, allows the application of a method to determine Hg(2+) levels in the range of 4.0-15.0 µM, with the limit of detection (LOD) calculated at 60.7 nM (3σ/slope). In addition, the fluorescence 'turn-off' and color 'fading-out' happen to the mixture of RN3-Hg(2+) by further addition of I(-) or S(2-). The reversible switching cycles of fluorescence intensity upon alternate additions of Hg(2+) and S(2-) demonstrate that RN3 can perform as an INHIBIT logic gate. Furthermore, the potential of RN3 as a fluorescent probe has been demonstrated for cellular imaging.


Assuntos
Corantes Fluorescentes/química , Lógica , Mercúrio/análise , Imagem Molecular/métodos , Rodaminas/química , Sobrevivência Celular/efeitos dos fármacos , Colorimetria , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/farmacologia , Células HeLa , Humanos , Estrutura Molecular , Rodaminas/síntese química , Rodaminas/farmacologia , Espectrometria de Fluorescência
10.
Sci Rep ; 4: 4841, 2014 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-24788080

RESUMO

Environmental pollution by emerging contaminants, e.g. pharmaceuticals, has become a matter of widespread concern in recent years. We investigated the membrane transport of diclofenac and its toxic effects on gene expression and the development of zebrafish embryos. The association of diclofenac with the embryos conformed to the general partition model at low concentration, the partition coefficient being 0.0033 ml per embryo. At high concentration, the interaction fitted the Freundlich model. Most of the diclofenac remained in the extracellular aqueous solution with less than 5% interacting with the embryo, about half of which was adsorbed on the membranes while the rest entered the cytoplasm. Concentrations of diclofenac over 10.13 µM were lethal to all the embryos, while 3.78 µM diclofenac was teratogenic. The development abnormalities at 4 day post treatment (dpt) include shorter body length, smaller eye, pericardial and body edema, lack of liver, intestine and circulation, muscle degeneration, and abnormal pigmentation. The portion of the diclofenac transferred into the embryo altered the expression of certain genes, e.g. down-regulation of Wnt3a and Gata4 and up-regulation of Wnt8a. The alteration of expression of such genes or the regulation of downstream genes could cause defects in the cardiovascular and nervous systems.


Assuntos
Diclofenaco/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Peixe-Zebra/genética , Animais , Anti-Inflamatórios não Esteroides/toxicidade , Ecotoxicologia , Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Desenvolvimento Embrionário/genética , Exposição Ambiental/efeitos adversos , Poluentes Ambientais/toxicidade , Fatores de Tempo
11.
J Mater Chem B ; 2(28): 4467-4472, 2014 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-32261548

RESUMO

A facile one-step Cu(i)-catalyzed "click" reaction, between a dansyl-azide and a propargyl-substituted rhodamine B hydrazide, is employed to fabricate a novel FRET ratiometric "off-on" fluorescent probe. The sensitive emission of the donor, a dansyl group, overlaps perfectly with the absorption of the acceptor, xanthene in the open-ring rhodamine. The proposed probe shows high selectivity towards Cu2+. The ratio of emission intensities at 568 and 540 nm (I568/I540) exhibits a drastic 28-fold enhancement upon addition of Cu2+. The probe shows an excellent linear relationship between emission ratios and the concentrations of Cu2+ from 10 to 50 µM, with a detection limit (S/N = 3) of 0.12 µM. The preliminary cellular studies demonstrated that the probe is cell membrane permeable and could be applied for ratiometric fluorescence imaging of intracellular Cu2+ with almost no cytotoxicity. The ingenuity of the probe design is to construct a FRET donor-acceptor interconnector and a selective receptor simultaneously by "click" reaction. The strategy was verified to have great potential for developing novel FRET probes for Cu2+.

12.
Hum Pathol ; 44(10): 2199-203, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23954140

RESUMO

α-Thalassemia/mental retardation syndrome X-linked protein (ATRX) and death domain-associated protein (DAXX) genes are tumor suppressors whose mutations have been identified in sporadic pancreatic neuroendocrine tumors as well as in patients with MEN1. However, it is unknown whether ATRX and DAXX alterations are specific for pancreatic neuroendocrine tumor. In addition, the association of ATRX/DAXX protein loss with tumor cell proliferation has not been examined. We, therefore, immunostained ATRX and DAXX in 10 gastric, 15 duodenal, 20 rectal, 70 pancreatic, and 22 pulmonary neuroendocrine tumors with 15 nonneoplastic pancreases and 27 pancreatic adenocarcinomas to elucidate the site-specific roles of ATRX/DAXX abnormalities. At least 1 loss of ATRX and DAXX immunoreactivity was detected in all neuroendocrine tumor cases but not in any of nonneoplastic pancreatic tissues or pancreatic adenocarcinomas. The loss of DAXX protein was correlated with the Ki-67 index (ATRX, P = .904; DAXX, P = .044). The status of DAXX immunoreactivity correlated positively with World Health Organization histologic grade (P = .026). These results suggest that the status of ATRX or DAXX protein loss in neuroendocrine tumor differed among the organs in which these tumors arose, and these proteins may play site-specific roles in the development of these tumors.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Gastrointestinais/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Neoplasias Pulmonares/patologia , Deficiência Intelectual Ligada ao Cromossomo X/patologia , Tumores Neuroendócrinos/patologia , Talassemia alfa/patologia , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Neoplasias Gastrointestinais/metabolismo , Humanos , Neoplasias Pulmonares/metabolismo , Masculino , Deficiência Intelectual Ligada ao Cromossomo X/metabolismo , Pessoa de Meia-Idade , Tumores Neuroendócrinos/metabolismo , Pâncreas/metabolismo , Pâncreas/patologia , Proteínas Repressoras , Adulto Jovem , Talassemia alfa/metabolismo
13.
Environ Monit Assess ; 185(1): 39-44, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22286838

RESUMO

An on-site solid-phase extraction, consisting of the sorption, the separation and the elution function units, was designed for in situ preconcentration of heavy metals ions. The D401 resin powder was employed as sorbent to capture Pb(2+), Cu(2+), Zn(2+), Cd(2+), Co(2+), and Ni(2+), and then they desorbed with 2 mol/L nitric acid as eluent. Under the optimized conditions, these heavy metals ions in West Lake, Taihu Lake, and Yangtze River of China were captured and then determined by ICP-OES with the recovery of 92.5% to 111.5%. The on-site solid-phase extraction achieved a quick preconcentration of heavy metals to avoid the transport and storage of a large volume water sample. It is suitable for in situ monitoring of water quality in mountains, tablelands or other remote areas.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , China , Lagos/química , Metais Pesados/química , Poluentes Químicos da Água/química
15.
Molecules ; 17(5): 6046-55, 2012 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-22614859

RESUMO

Sulfide is an important water pollutant widely found in industrial waste water that has attracted much attention. S²â», as a weak acidic anion, is easy hydrolyzed to HS⁻ and H2S in aqueous solution. In this study, biological tests were performed to establish the toxicity of sulfide solutions on luminescent bacteria. Considering the sulfide solution was contained three substances--S²â», HS⁻ and H2S--the toxicity test was performed at different pH values to investigate which form of sulfide increased light emission and which reduced light emission. It was shown that the EC50 values were close at pH 7.4, 8.0 and 9.0 which were higher than pH 5 and 10. The light emission and sulfide concentrations displayed an inverse exponential dose-response relationship within a certain concentration range at pH 5, 6.5 and 10. The same phenomenon occurred for the high concentration of sulfide at pH 7.4, 8 and 9, in which the concentration of sulfide was HS⁻ >> H2S > S²â». An opposite hormesis-effect appeared at the low concentrations of sulfide.


Assuntos
Bactérias/efeitos dos fármacos , Luminescência , Sulfetos/farmacologia , Bactérias/metabolismo , Concentração de Íons de Hidrogênio , Solubilidade , Soluções , Sulfetos/química , Poluentes da Água/química
16.
PLoS One ; 7(4): e32818, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22509249

RESUMO

The increased application of nanomaterials has raised the level of public concern regarding possible toxicities caused by exposure to nanostructures. The interactions of nanosized hydroxyapatite (HA) with cytochrome c and hemoglobin were investigated by zeta-potential, UV-vis, fluorescence and circular dichroism. The experimental results indicated that the interactions were formed via charge attraction and hydrogen bond and obeyed Langmuir adsorption isotherm. The two functional proteins bridged between HA particles to aggregate into the coralloid form, where change of the secondary structure of proteins occurred. From effects of nanosized HA, SiO(2) and TiO(2) particles on the zebrafish embryos development, they were adsorbed on the membrane surface confirmed by the electronic scanning microscopy. Nano-HA aggregated into the biggest particles around the membrane protein and then caused a little toxicity to development of zebrafish embryos. The SiO(2) particles were distributed throughout the outer surface and caused jam of membrane passage, delay of the hatching time and axial malformation. Maybe owing to the oxygen free radical activity, TiO(2) caused some serious deformity characters in the cardiovascular system.


Assuntos
Durapatita/metabolismo , Durapatita/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/fisiologia , Desenvolvimento Embrionário/efeitos dos fármacos , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Adsorção , Animais , Citocromos c/metabolismo , Durapatita/química , Concentração de Íons de Hidrogênio , Larva/efeitos dos fármacos , Nanoestruturas/toxicidade , Concentração Osmolar , Ligação Proteica , Dióxido de Silício/química , Dióxido de Silício/toxicidade , Temperatura , Titânio/química , Titânio/toxicidade , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/química
17.
Yi Chuan ; 34(1): 95-101, 2012 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-22306878

RESUMO

SOD is an important enzyme which exists in eukaryote extensively and plays an essential role in stress-tolerance of higher plants. A cDNA of Cu/ZnSOD gene was cloned from Galega orientalis L. using rapid amplification of cDNA ends (RACE) method. The full-length of cDNA sequence is 935 bp, included a 600 bp open reading frame which encoded a 199-amino-acid polypeptide. The molecular weight of this protein was 20.35 kDa. The results of Real-Time PCR indicated that the expression level of Cu/ZnSOD gene was the highest in leaves, moderate in stems, and the least in roots. The expression of Cu/ZnSOD gene under stress of NaCl and PEG was up-regulated firstly and then declined. The expression level was significantly lower than the control after 24 h treated with NaCl. Abscisic acid downregulated the expression of Cu/ZnSOD gene. The result of subcellular localization indicated that Cu/ZnSOD was located in chloroplast. Gene Cu/ZnSOD mainly expressed in the green organs of G. orientalis and played a certain role in resisting osmotic stress.


Assuntos
Clonagem Molecular , Galega/enzimologia , Regulação Enzimológica da Expressão Gênica , Proteínas de Plantas/genética , Superóxido Dismutase/genética , Sequência de Aminoácidos , Galega/classificação , Galega/genética , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/metabolismo , Superóxido Dismutase/metabolismo
18.
Carbohydr Polym ; 89(1): 185-92, 2012 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-24750622

RESUMO

The sorption of copper ions onto natural bamboo sawdust with cellulose-lignin polymeric structure strongly depends on pH. The adsorption capacity for copper ions increases as increasing pH and copper loadings. The fitting of copper pH boundary curve by NEM surface complexation models shows that: three-sites model including the ion exchange reaction of permanent charge fits better than two-sites model. The incorporation of the hydrated ion reaction gives better fitting results. XAFS study shows that: copper ions mainly form inner complexation with sawdust, but there is no obvious evidence on the complexation of carboxylic acid groups with copper ions. EXAFS fitting result shows that: as pH rises, the spatial configuration of copper ions shifts from tetrahedron to octahedron. Meanwhile the increase in the coordination number indicates that hydrated copper ions participate in the adsorption. Both XANES and EXFAS spectrum offer a similar explanation for copper adsorption in the range of experimental and fitting errors.


Assuntos
Bambusa , Cobre/química , Modelos Teóricos , Adsorção , Celulose/química , Concentração de Íons de Hidrogênio , Troca Iônica , Lignina/química , Madeira , Espectroscopia por Absorção de Raios X
19.
Environ Sci Pollut Res Int ; 19(4): 1237-44, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22057851

RESUMO

INTRODUCTION: Ethylenediamine-grafted multiwalled carbon nanotubes (MWCNTs-EDA-I and MWCNTs-EDA-II) are optimized and employed to investigate the preconcentration of lead ions (Pb(II)) in trace level. RESULTS: The results show that Pb(II) can be adsorbed quantitatively on the optimized MWCNTs in the range of pH 4-7 and MWCNTs-EDA-I has a higher maximum Pb(II) adsorption capacity (157.19 mg/g) than MWCNTs-EDA-II (89.16 mg/g). The adsorbed Pb(II) can be eluted completely using 5 mL of 1 mol/L HNO(3). DISCUSSION: A new approach using a microcolumn packed with the obtained MWCNTs-EDA-I has been developed for the preconcentration of trace amount of Pb(II). Parameters influencing the preconcentration of Pb(II), such as pH of the sample, sample volume, elution solution, and interfering ions, have been examined and optimized in detail. Under optimum experimental conditions, the limit of detection is 0.30 ng/mL with the enrichment factor of 60. The relative standard deviation (R.S.D) was 2.6% at the 20 ng/mL Pb(II) level. CONCLUSION: The method has been applied for the preconcentration of trace amount of Pb(II) in environmental water samples with satisfying results.


Assuntos
Etilenodiaminas/química , Chumbo/química , Nanotubos de Carbono/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Oxirredução , Extração em Fase Sólida
20.
Chem Commun (Camb) ; 47(48): 12810-2, 2011 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-22051684

RESUMO

The CR@BaSO(4) hybrid was synthesized, characterized and used as an acid rain-indicating (ARI) material. A painted ARI umbrella was discolored after exposure to simulated acid rain of pH 5 or less and returned to the initial color after the rain stopped. Such a functionalized material may make acid rain visual to remind people in real-time.


Assuntos
Chuva Ácida/análise , Sulfato de Bário/química , Vermelho Congo/química , Concentração de Íons de Hidrogênio , Nanoestruturas/química
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