Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Environ Geochem Health ; 46(2): 63, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38302793

RESUMO

This study investigates the effect of boundary conditions and treatment-time on the electro-desalination of artificially-contaminated soil. The effect of ion exchange membranes (IEM), calcium chloride (CaCl2), and ethylenediaminetetraacetic acid (EDTA) on the removal of salt (i.e., Na+, Cl-, and Ca2+) and metal (i.e., Co2+ and Fe2+) ions from the soil by electrokinetic (EK) was studied. The outcomes demonstrate that an increase in treatment-time decreases the electroosmosis and ion removal rate, which might be attributed to the formation of acid-base fronts in soil, except in the IEM case. Because a high pH jump and electroosmotic flow (EOF) of water were not observed within the soil specimen due to the IEM, the removal of ions was only by diffusion and electromigration. The collision of acid-base fronts produced a large voltage gradient in a narrow soil region with a reduced electric field (EF) in its remaining parts, causing a decrease in EOF and ion transport by electromigration. The results showed that higher electroosmosis was observed by using CaCl2 and EDTA; thus, the removal rate of Co2+, Na+, and Ca2+ was greater than Cl- due to higher EOF. However, for relatively low EOF, the removal of Cl- exceeded that of Co2+, Na+, and Ca2+, possibly due to a lack of EOF. In addition, the adsorption of Fe2+ in soil increased with treatment-time due to the corrosion of the anode during all EK experiments except in the case of IEM, where an anion exchange membrane (AEM) was introduced at the anode-soil interface.


Assuntos
Recuperação e Remediação Ambiental , Poluentes do Solo , Ácido Edético , Solo , Cloreto de Cálcio , Íons , Poluentes do Solo/análise
2.
Environ Res ; 242: 117736, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38007083

RESUMO

Environmental contamination is a global challenge that impacts every aspect of ecosystem. The contaminants from anthropogenic or industrial trash continually recirculate into the environment, agricultural land, plants, livestock, and ultimately into humans by way of the food chain. After an increase in human and farmland animal deaths from illnesses due to contaminated drinking water, toxic metal water poisoning has remained a global concern. Diverse environmental and enforcement organisations have attempted to regulate the activities that serve as precursors to these heavy metals which have been proven ineffective. These unnecessary metals have severely hampered most biological processes. The presence of hazardous metals, which are harmful at extremely high levels and have a negative effect on the health of living bodies generally degrades the nutritional value of water. In order to evaluate the heavy metals (Cu, Ni, and Fe) toxicity of groundwater in pri-urban areas, the current study was conducted that have been considered as advance solution to tackle climate change which influence coastal ecosystem. Additionally, the impacts of soil and plant (spinach and brassica) contamination from groundwater were evaluated. The heavy metals were examined in the soil and groundwater samples (Pb, Fe and Ni). While Fe concentrations in water samples were found to be high as 1.978 mg/L as compared to Ni and Cu values low. According to WHO guidelines, the mean value of Fe exceeds the limit value. Similarly, Cu had a higher mean value (0.7 mg/L) in soil samples than other metals (Ni and Fe). In comparison to Ni and Cu, the Fe concentrations in spinach and brassica plants samples are greater, at 17.2 mg/L and 3.22 mg/L, respectively. The possible effects of metal poisoning of groundwater and plants on human health have been assessed using the Hazard Quotient (HQ), Evaluated Daily Intake (EDI), and Incremental Life Time Cancer Risk formulas (ILTCR). When drinking Ni-contaminated water, humans are more at risk of developing cancer (0.0031) than Fe and Cu. Metal concentrations in water and brassica showed substantially more scattered behaviour on the plot and no meaningful relationship, although PCA and masked matrix correlation showed a fair association between Ni and Cu in brassica (r2: 0.46) and Fe and Ni in spinach (r2: 0.31). According to the study's findings, it is anticipated that special management and groundwater monitoring will be needed in the examined area to reduce the health risks related to drinking water that has been contaminated with metals.


Assuntos
Água Potável , Metais Pesados , Neoplasias , Poluentes do Solo , Animais , Humanos , Monitoramento Ambiental/métodos , Ecossistema , Poluentes do Solo/análise , Metais Pesados/toxicidade , Metais Pesados/análise , Resíduos Industriais/análise , Solo , Medição de Risco
3.
Luminescence ; 38(9): 1624-1631, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37386874

RESUMO

Using the melt quenching technique, a lithium zinc borate glass (LZB) system with trivalent dysprosium ions (Dy3+ ) was synthesized, and the luminescence and lasing properties of these materials were examined for the generation of white light. Structural investigation through X-ray diffraction revealed that the prepared glass had an amorphous nature. The optimized glass containing 0.5 Dy3+ had a direct optical band gap of 2.782 eV and an indirect optical band gap of 3.110 eV. A strong excitation band at 386 nm (6 H15/2 →4 I13/2 ) was recognized in the ultraviolet (UV) light region of its excitation spectrum. Emission bands could be seen in the photoluminescence spectrum at 659, 573, and 480 nm under the 386 nm excitation. These transitions of emission resembled electronic transitions such as (4 F9/2 →6 H11/2 ), (4 F9/2 →6 H13/2 ), and (4 F9/2 →6 H15/2 ). In a pristine glass matrix, the higher intensity ratio of yellow to blue can result in the production of white light. The optimized Dy3+ ion concentration was observed to be 0.5 mol%. In addition, an analysis of lifetime decay was conducted for all synthesized glasses, and their decay trends were systematically investigated. Noticeably, we assessed the photometric parameters and found that they were close to the white light standard. Furthermore, a cytotoxicity study was carried out using lung fibroblast (WI-38) cell lines for the optimized 0.5Dy3+ -doped LZB glass and it appeared to be noncytotoxic. It is clear from the results that the noncytotoxic LZB glass doped with 0.5 Dy3+ ions could be a suggestive choice for the manufacture of white light-emitting diodes and lasers using near-UVs.


Assuntos
Luz , Luminescência , Raios Ultravioleta , Medições Luminescentes , Íons
4.
Environ Res ; 231(Pt 2): 116147, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37187307

RESUMO

Both the environment and human health have suffered as a result of excessive and irrational pesticide use. The human body is vulnerable to a wide range of illnesses brought on by prolonged exposure to or intake of food contaminated with pesticide residues, including immunological and hormonal abnormalities and the development of certain tumors. Sensors based on nanoparticles stand out from more conventional spectrophotometry analytical methods due to their low detection limits, high sensitivity, and ease of use; that is why the demand for simple, fast, and less expensive sensing methods increases daily and presents myriad uses. Such demands are fulfilled by employing paper-based analytical devices having intrinsic properties. The presented work reports an on-site, easy-to-handle, and disposable paper-based sensing device for performing fast screening along with readout from a smartphone. The fabricated device utilizes luminescent silica quantum dots, immobilized into a paper cellulose matrix, and the resonance energy transfer phenomenon is employed. The silica quantum dots probes were fabricated from citric acid and, by undergoing physical adsorption, were confined on the nitrocellulose substrate in small wax-traced spots. The silica quantum dots were excited by smartphone ultraviolet LED, acting as an energy source and for capturing the image. The obtained LOD is 0.054 µM, and the coefficient of variation is less than 6.1%, comparable to the result obtained by UV-Visible and fluorometric analysis under similar experimental conditions. In addition, high reproducibility (≥9.8%) and high recovery ≥90% were obtained in spiked blood samples. The fabricated sensor sensitively detected pesticides giving a LOD of 2.5 ppm along with the development of yellow color within a short period of 5 min. The sensor functions well when sophisticated instrumentation is not accessible. The presented work shows the potential of the paper strip for the on-site detection of pesticides in biological and environmental samples.


Assuntos
Praguicidas , Pontos Quânticos , Humanos , Praguicidas/análise , Pontos Quânticos/química , Dióxido de Silício/química , Reprodutibilidade dos Testes , Luminescência
5.
Chemosphere ; 312(Pt 2): 137327, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36410509

RESUMO

Green production of nanomaterials are restrict toxic substances and motivated the noxious free environment. Photocatalysis and antibacterial resistance are more promising and efficient fields for their chemical reductants and clean environment. Herein, we adopted a green and simple method for the biosynthesis of MgO NPs using Manilkara zapota as a bio source. Recently, the green synthesis of magnesium oxide nanoparticles has been a keen interest amongst researchers and scientists due to its simplicity eco-friendliness, non-toxic, inexpensive and potential to perform as an antibacterial agent. Activated carbon/Magnesium oxide (AC/MgO) photocatalyst was blended through a simple solution evaporation method. The surface electron microscopy (SEM) study reviles that AC/MgO had smooth and aggregated particles. The Fourier transform infrared (FT-IR) and x-ray diffraction (XRD) study confirms the structural formation and incorporation of nanoparticles into the AC matrix. Results confirmed the flourishing integration of MgO NPs over the activated carbon matrix. The electron movement and valency of AC/MgO photocatalyst reduced the bandgap and their findings were characterized by ultra visible diffuse reflectance spectroscopy (UV-DRS) and x-ray photoelectron spectroscopy (XPS). The blended AC/MgO photocatalyst was analyzed for photodegradation of Rhodamine- B (Rh-B) dye using a UV-visible spectrophotometer. The degradation study projects that the AC/MgO photocatalyst degrades (Rh-B) dye with 99% efficiency under simulated solar irradiation. This efficient degradation of (Rh-B) dye by AC/MgO photocatalyst is ascribed to the synergetic AC as catalytic support and adsorbent and MgO as photocatalyst. Finally, the photocatalytic material shows a better bactericidal effect in both gram-positive bacteria Escherichia coli-745 and gram-negative bacteria Staphylococcus aureus-9779. The AC/MgO photocatalyst is effectively used in bacteriocidal and photocatalytic removal of dyes and can be used for further development of water reuse and bio-medical fields. In addition, this research shows a viable method for synthesizing a cheap and effective AC/MgO for the photocatalytic destruction of organic pollutants.


Assuntos
Óxido de Magnésio , Nanopartículas , Óxido de Magnésio/farmacologia , Carvão Vegetal/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Antibacterianos/farmacologia , Corantes , Escherichia coli
6.
Chemosphere ; 310: 136841, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36243088

RESUMO

Implication of natural resources for manufacturing of nanoparticles is sustainable, economical and contaminant free approach towards ecological and medical applications. Herein, CeO2 and Ag/CeO2 nanoparticles are green synthesized from Morinda tinctoria plant extract. The phase structure, surface morphology, optical identity, Ce(III) and Ce(IV) valency of the synthesized CeO2 and Ag/CeO2 nanoparticles are explored. The X-ray diffraction analysis indicated the formation of cubic phase CeO2 and cubic silver decorated CeO2 nanoparticles. Fourier transform infrared (FTIR) spectroscopy revealed the metal decoration of CeO2 nanoparticles, metal-oxygen stretching, indicating the plant molecules reduction and stabilization. UV-visible spectroscopy shown the decreased band gap owing to silver modification. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs displayed spherical morphology of the nanoparticles. Elemental composition and sample purity is assessed by energy dispersive spectroscopy (EDS). Double oxidation of Ce, double splitting energy of Ag and lattice oxygen are observed from X-ray photoelectron spectroscopy (XPS). Photocatalytic activity of Ag/CeO2 exposed the enhanced photocatalytic activity up to 94% where CeO2 nanoparticles gave 60% degradation of bromophenol blue (BB). The plasmonic decoration of silver on the ceria surface induced the charge separations and free radical reactions. Moreover, Ag/CeO2 nanoparticles are seen as superior antibacterial agents than CeO2 towards both E.coli and S.aureus. Hence, the silver decorated metal oxide photocatalyst successfully degraded the BB dye and inactivated the bacterial strains. This report established a future research in green synthesis of multipurpose metal nanoparticles.


Assuntos
Nanopartículas Metálicas , Prata , Prata/química , Antibacterianos/química , Extratos Vegetais/química , Nanopartículas Metálicas/química , Escherichia coli , Espectroscopia de Infravermelho com Transformada de Fourier , Oxigênio , Difração de Raios X , Química Verde
7.
J Sep Sci ; 45(4): 804-811, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34894085

RESUMO

A comparative study of chiral separation of pantoprazole and rabeprazole is carried out using supercritical fluid chromatography and high-performance liquid chromatography. The columns used were Chiralpak IA and Chiralpak IE. The best mobile phase in supercritical fluid chromatography was carbon dioxide-0.2% triethylamine in methanol (60:40) and 0.1% triethylamine in n-hexane-ethanol (50:50) in high-performance liquid chromatography. For supercritical fluid chromatography, values of the retention factor of pantoprazole enantiomers were 3.97 and 4.88. These values for rabeprazole enantiomers were 6.10 and 7.52. The values of separation and resolution factor for pantoprazole and rabeprazole were 1.23 and 1.23 and 2.20 and 3.36, respectively. Similarly, for high-performance liquid chromatography, the values of retention factor for enantiomers of pantoprazole were 4.02 and 7.32. These values for rabeprazole enantiomers were 5.32 and 7.88, respectively. The values of separation and resolution factor for pantoprazole and rabeprazole were 1.82 and 1.48 and 9.22 and 6.58, respectively. A comparison was carried out, which confirmed supercritical fluid chromatography as the best method due to its fastness, eco-friendly, and inexpensiveness. The reported methods are effective, efficient, and reproducible and may be used to separate and identify pantoprazole and rabeprazole in any unknown samples.


Assuntos
Cromatografia com Fluido Supercrítico , Inibidores da Bomba de Prótons , Cromatografia Líquida de Alta Pressão , Cromatografia com Fluido Supercrítico/métodos , Pantoprazol , Inibidores da Bomba de Prótons/química , Rabeprazol , Estereoisomerismo
8.
RSC Adv ; 10(38): 22377-22386, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-35514602

RESUMO

NiO alloyed with aluminum, Ni1-x Al x O, is analyzed in terms of its stoichiometry, electronic and transport properties, as well as interfacial band alignment with Si to evaluate its potential use as a hole transport layer (HTL) in p-i-n type solar cells. The analysis is based on component material and slab structural simulations, as well as simulated and measured angle-resolved valence-band photoemission spectroscopy (PES) data, in order to reveal the best suitable stoichiometry. It is concluded that the ionization energy from the highest occupied states tends to increase with Al content as the simulated work function grows from 4.1 eV for pure NiO to 4.7 eV for heavily alloyed Al0.50Ni0.50O. The electronic structure as a function of the interface design between crystalline silicon and the transport layer is used to assess the band lineup and its correlation with the discontinuity of the affinities. The affinity rule is tested by evaluating the workfunctions of the component layers and justified best for a particular Ni-enriched interface design. Technology Computer-Aided Design (TCAD) device simulations show, that the band offset between oxide and crystalline silicon remains within the range of values to sustain a staggering alignment - a condition suitable for effective charge separation, similar to a situation in a tunneling diode. The self-energy of the hole carriers is estimated by contrasting simulated and measured photoemission data, which in the case of non-annealed Al-rich samples is shown to be an order of magnitude higher due to the disorder effects. The work functions derived from the measured PES data for the epitaxially grown oxide films with nearly identical alloy stoichiometry correlate well with the simulated values. The findings suggest that the optimal HTL is formed by starting with a pure Ni layer, followed by a graded doping Al x Ni1-x O, with x high at contact/oxide interface and low at the oxide/semiconductor.

9.
J Healthc Eng ; 2019: 9691568, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30906516

RESUMO

Six Sigma is used heavily in various industrial sectors, yet no noticeable applications are seen in healthcare logistics. This paper reveals the special case of healthcare logistics where cost reduction is not the only factor considered in project selection; performance and criticality of each item in the logistics system are of high importance as well. This paper provides a proposed framework to apply Six Sigma in the area of healthcare logistics. It also presents a case study implementing the proposed framework at a Jordanian hospital. In the case study, the paper reveals how the modifications of the define phase to take into consideration the criticality, cost, and performance of items make typical Six Sigma methodology very beneficial for healthcare logistics. In addition, it shows how the Six Sigma project selection can be done to deal effectively with healthcare logistics issues. This paper paves the road for research to elaborate on ways to use Six Sigma in the area of improving healthcare logistics.


Assuntos
Eficiência Organizacional , Administração Hospitalar , Gestão da Qualidade Total/métodos , Custos de Medicamentos , Custos de Cuidados de Saúde , Hospitais , Jordânia , Modelos Organizacionais , Avaliação de Processos e Resultados em Cuidados de Saúde , Serviço Hospitalar de Compras , Indicadores de Qualidade em Assistência à Saúde , Inquéritos e Questionários
10.
J Pediatr Adolesc Gynecol ; 30(6): 641-645, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28645886

RESUMO

STUDY OBJECTIVE: The objective of this study was to assess short-term benefits and risks of utero-vaginal anastomosis done for cases of cryptomenorrhea due to cervical atresia with vaginal aplasia. DESIGN: Prospective study. SETTING: Surgical procedures were done between December 2013 and September 2015 at the department of Obstetrics and Gynecology, Cairo University Hospital. PARTICIPANTS: Five patients who had cryptomenorrhea due to cervical atresia associated with vaginal aplasia were included. INTERVENTIONS: Utero-vaginal anastomoses were performed in 2 stages; a stage of McIndoe vaginoplasty and a stage of excision of the atretic cervical tissue and anastomosing the uterus to the neovagina. Follow-up was done by gynecological and ultrasound examination in a duration ranged from 12 to 36 months. MAIN OUTCOME MEASURES: Occurrence of regular menstrual flow and relief of the severe cyclic pain. RESULTS: All patients had relief of the severe cyclic pain. Four patients had regular menstrual flow. One patient developed occlusion of the track after 1 year and needed dilatation once. Three patients developed low vaginal stenosis without occlusion of the track. One patient had rectal injury repaired without causing postoperative morbidity. CONCLUSION: Uterovaginal anastomosis is a promising conservative management option for cervical atresia with vaginal aplasia, which has benefits but is not free of risks. Long-term follow-up is still needed to judge its feasibility. We recommend performing McIndoe vaginoplasty as a starting stage before the anastomosis preferably in a separate setting.


Assuntos
Anastomose Cirúrgica/métodos , Colo do Útero/anormalidades , Anormalidades Congênitas/cirurgia , Útero/cirurgia , Vagina/anormalidades , Adolescente , Adulto , Amenorreia , Anastomose Cirúrgica/efeitos adversos , Colo do Útero/cirurgia , Feminino , Seguimentos , Hematometra/etiologia , Hematometra/cirurgia , Humanos , Menstruação , Estudos Prospectivos , Medição de Risco , Resultado do Tratamento , Útero/anormalidades , Vagina/cirurgia , Adulto Jovem
11.
Neurosci Lett ; 440(3): 222-6, 2008 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-18571322

RESUMO

It has been shown that increased estrogen can down-regulate its receptor, but there is no data to determine if that mechanism acts in the fetal brain as a consequence of high maternal estrogen levels. The aim of this study was to explore the expression of estrogen receptor (ER) in the developing fetal brain at 16, 19 and 21 days gestation (dg). The results revealed that both ERalpha and ERbeta isoforms, and some of their variants, were present in rat fetal brain at the transcript level and at the protein level. PCR results showed that the amount of ERalpha and ERbeta mRNA did not change significantly between 16, 19 and 21 dg; however, changes in protein expression were apparent. Two bands were detected for ERalpha protein by immunoblotting: the expression of the 73 kDa band, relative to the expression of actin, decreased significantly between 16 and 21 dg, while expression of the 67 kDa band did not change. Multiple variants of ERbeta were detected, including wild type ERbeta, ERbeta2 and ERbetaDelta5; the amounts of all decreased significantly, relative to the amount of actin, between 16 and 21 dg. A decrease in protein expression of some of the ER variants without an equivalent decrease in the amount of mRNA suggests that high levels of estrogen might triggered posttranslational modifications of ER, including the ER ubiquitin-dependent proteolysis. Overall, these findings suggest that the fetal brain might be less responsive to estrogens during late pregnancy in the rat, thereby minimizing the known harmful effects of high levels of circulating maternal estrogens.


Assuntos
Encéfalo/embriologia , Encéfalo/metabolismo , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/genética , Receptor beta de Estrogênio/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Fatores Etários , Animais , Embrião de Mamíferos , Feminino , Peso Molecular , Gravidez , RNA Mensageiro/metabolismo , Ratos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA