Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-39263989

RESUMO

Our study represents the first attempts to describe the ultrastructure features in addition to SEM-EDX analysis of the pecten oculi of the nocturnal, visually active Eurasian stone-curlew. The present study was carried out on 10 normal pecten oculi from the migrant Eurasian stone-curlew (Burhinus oedicnemus) that was captured from the Northern Egyptian coast, Edku Lake, Edku, Behera, Egypt. The intraocular folded quadrilateral fan black pecten oculi was observed on the posteroinferior wall of the eyeball. The pecten oculi had 18-20 pleats, with narrow spaces in-between. Our SEM findings showed a tortuous, coiled pecteneal surface due to numerous blood capillaries. The apical part was oriented toward the ciliary body, but the basal part was derived from the retina, just behind the optic nerve. The outer pleat surfaces are covered by the vitreopecteneal limiting membrane, which carries numerous hyalocyte cells on the outer pleat surface. The transverse sections revealed numerous blood capillaries surrounded by numerous melanin granules. Each basal part was surrounded by a thin, elevated ridge. Our SEM-EDX analysis revealed that carbon is the highest (half percent), oxygen represents about one-third, and nitrogen is one-fifth percent of all elements. The lowest elements are sulfate at the apical part and phosphorus in the middle and basal parts. In conclusion, our findings reveal that the number of pecteneal pleats is related to the nocturnal active visual pattern and the lifestyle of this migratory bird.

2.
Int J Legal Med ; 138(1): 123-137, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37227490

RESUMO

Traces from bodies can be of various nature, for example of biological or inorganic origin. Some of these historically have received more consideration than others in forensic practice. Samplings of gunshot residues or biological fluid traces are commonly standardized, whereas macroscopically invisible environmental traces are usually ignored. This paper simulated the interaction between a cadaver and a crime scene by placing skin samples on the ground of five different workplaces and inside the trunk of a car. Traces on samples were then investigated through different approaches: the naked eye, episcopic microscope, Scanning Electron Microscopy (SEM) with Energy-dispersive X-ray spectroscopy (EDX) and Energy Dispersive X-Ray Fluorescence (ED-XRF). The purpose is to provide the forensic scientist with the awareness of the value of debris on skin and then to highlight implications for forensic investigations. Results demonstrated that even naked eye observation can reveal useful trace materials, for defining the possible surrounding environment. As a next step, the episcopic microscope can increase the number of visible particulates and their analysis. In parallel, the ED-XRF spectroscopy can be useful to add a first chemical composition to the morphological data. Finally, the SEM-EDX analysis on small samples can provide the greatest morphological detail and the most complete chemical analysis, although limited, like the previous technique, to inorganic matrices. The analysis of debris on the skin, even with the difficulties due to the presence of contaminants, can provide information on the environments involved in criminal events that can add to the investigation framework.


Assuntos
Pele , Ferimentos por Arma de Fogo , Humanos , Microscopia Eletrônica de Varredura , Raios X , Espectrometria por Raios X , Pele/química
3.
J Forensic Leg Med ; 79: 102137, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33647534

RESUMO

Partially or totally skeletonized bodies are undoubtedly the most challenging scenario to deal with for forensic pathologists and anthropologists. Indeed, in such cases, being able to figure out the cause and manner of death is often tricky. Human remains require to be washed and cleaned before a thorough assessment of any signs of trauma. However, bones and any fragment of more or less putrefied soft tissues may be home to crucial traces for investigative purposes. They are often located in the context of apparently meaningless dirt and, sometimes they are even invisible to the naked eye. Therefore, their careless cleaning inevitably leads to an unintentional loss of such traces with a negative impact on subsequent investigations. For these reasons before proceeding with cleaning, exhaustive examination and sampling must be carried out. In particular fragments of soft tissues, even if putrefied, are absolutely not to be considered as a hindrance for forensic purposes, since they could still provide valuable information after histological examination. Finally, forward-thinking professionals should think about the possible presence of exogenous micro-traces of forensic concern and collect specimens to be analyzed through in-depth analyses, such as Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM/EDX). The present series of cases demonstrates that crucial forensic information can be obtained through the analysis of apparently meaningless residues and even of micro-traces not visible to the naked eye and mixed with trivial dirt.


Assuntos
Restos Mortais , Manejo de Espécimes , Antropologia , Feminino , Patologia Legal , Glicoforinas , Hemorragia/patologia , Humanos , Cristalino , Masculino , Metais , Microscopia Eletrônica de Varredura , Mudanças Depois da Morte , Estudos Retrospectivos , Espectrometria por Raios X , Coloração e Rotulagem
4.
Materials (Basel) ; 13(3)2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31979261

RESUMO

Cement-based materials are the most prevalent construction materials, and the conventional cutting techniques are still mostly used for fabricating the materials. However, these conventional cutting methods could generate undesirable micro-cracks and remove unintentional structural sections. This experimental study aims to evaluate the effects of the new fabricating method using laser on the microstructural characteristics of the cement-based materials. The experimental variables are laser cutting speed, water to cement ratio and material compositions. In order to compare the microstructure before and after the laser interaction, the microstructure of the cut surface is observed through scanning electron microscopy/energy dispersive X-Ray (SEM/EDX). After the laser interaction, the Material Removed Zone (MRZ) and Heat Affected Zone (HAZ) are observed on the cut surface. In MRZ, it is found that the glassy layer is thickened by an increasing amount of silicate-based materials in cement-based materials. In addition, it concluded that the amount of silicate-based material mixed in the cement-based materials affects the laser cutting quality.

5.
Int J Phytoremediation ; 22(2): 127-133, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31342761

RESUMO

A newly discovered nickel (Ni) hyperaccumulator plant, Breynia cernua (Phyllanthaceae) from the nickeliferous laterites of Acoje, Zambales, has elevated Ni concentrations. Its computed bioaccumulation factor is 1.7 and the translocation factor is 4.6. Leaf tissues which contain the highest Ni concentrations were analyzed using optical microscopy and Scanning Electron Microscopy with Energy-Dispersive X-ray (SEM/EDX). The results indicated that most of the Ni are stored in the epidermal cells of the leaves, followed by the mesophyll cells then the vascular bundles. The accumulation of Ni found in the subcellular locations, probably in the vacuoles, may prevent phytotoxicity that could affect the normal function of other cellular structures. A possible resistance mechanism through strain avoidance towards Ni accumulation makes B. cernua capable of tolerating elevated Ni concentrations in its tissues. The tolerance of B. cernua to Ni phytotoxicity suggests possible applications of this hyperaccumulator plant in phytoextraction technology.


Assuntos
Níquel , Plantas , Biodegradação Ambiental , Filipinas , Folhas de Planta
6.
Leg Med (Tokyo) ; 40: 43-46, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31351409

RESUMO

The retention of gauze within the mediastinum is considered an exceptional finding. We are presenting the case of a woman, affected by aorto-mitral valvulopathy, in whose mediastinum was found, during the autopsy, a gauzome without signs of active phlogosis, which had been "forgotten" in a previous surgery, acted 14 years before the death. A 39 y.o. woman had received surgical treatment of double aorto-mitral valve substitution and tricuspid plastic. At age 53, she successfully received surgery once again at a different hospital; she then started rehabilitation therapy, during which she deceased due to sudden hematemesis with infectious multi organ failure. During the autopsy, a 5 cm long surgical gauze was found in the mediastinum. A SEM/EDX (Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy) exam was ran on the foreign body and a sample of the same gauze used in the cardiac-surgical department of the hospital the victim had passed away in, to act a comparison between the two kinds of material. The exam showed a morphological difference between exogenous fibers incorporated within the gauzome and the control gauze. This case highlights the diagnostic and interpretative challenges in finding a foreign body within the mediastinum without signs of active phlogosis. SEM/EDX investigations executed on the gauzome and a "control gauze" allowed the attribution of malpractice to the first hospital the victim had been operated in 14 years before the exitus. The SEM/EDX exam confirms its importance in correctly identifying the case, which becomes an example for similar happenings.


Assuntos
Bandagens/efeitos adversos , Corpos Estranhos/diagnóstico por imagem , Imperícia/legislação & jurisprudência , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Autopsia , Procedimentos Cirúrgicos Cardíacos , Evolução Fatal , Feminino , Humanos , Pessoa de Meia-Idade
7.
PeerJ ; 6: e5322, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30065888

RESUMO

Industrial activities play a key role in the economic well-being of a country but they usually involve processes with a more or less profound environmental impact, including emission of pollutants. Among them, much attention has been given to airborne particulate matter (PM) whose exposure is ubiquitous and linked with several adverse health effects mainly due to its size and chemical composition. Therefore, there is a strong need to exploit monitoring systems for airborne PM able to provide accurate information on the potential health hazards and the specific emission sources for the implementation of adequate control strategies. The honey bee (Apis mellifera, L.) is widely used as an indicator of environmental pollution: this social hymenopteran strongly interacts with vegetables, air, soil, and water surrounding the hive and, as a consequence, pollutants from these sources are translated to the insect and to the hive products. During the wide-ranging foraging activity, the forager bee is known to collect samples of the main airborne PM pollutants emitted from different sources and therefore it can be used as an efficient PM sampler. In the present research, PM contaminating forager bees living nearby a cement factory and several kilometers away from it has been analysed and characterised morphologically, dimensionally and chemically through SEM/EDX. This provided detailed information on the role of both the cement manufacturing activities and the vehicular traffic as sources of airborne PM. This may indeed help the implementation of appropriate preventive and corrective actions that would effectively minimize the environmental spread of pollutant PM not only in areas close to the plant, but also in more distant areas.

8.
Molecules ; 23(6)2018 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-29843441

RESUMO

This work reports on the kinetics of electrochemical degradation of the resorcinol molecule, examined on nickel foam-based electrodes in contact with 0.1 M NaOH and 0.5 M Na2SO4 supporting electrolytes. The electrooxidation of resorcinol was examined on as-received, as well as on Pd-modified, nickel foam catalyst materials, produced via spontaneous deposition of trace amounts of palladium element. Electrochemical (cyclic voltammetry and a.c. impedance) experiments were carried out by means of a three-compartment, pyrex glass electrochemical cell, whereas continuous resorcinol electrooxidation tests were conducted galvanostatically (or potentistatically) with a laboratory-size, single-cell electrolyzer unit. In addition, quantitative determination of resorcinol and its possible electrodegradation products was performed by means of instrumental HPLC: High-Performance Liquid Chromatography/MS: Mass Spectrometry methodology. Also, SEM (Scanning Electron Microscopy) and EDX (Energy Dispersive X-ray spectroscopy) techniques were employed for Ni foam (Pd-modified Ni foam) surface characterizations.


Assuntos
Níquel/química , Resorcinóis/química , Hidróxido de Sódio/química , Sulfatos/química , Catálise , Eletroquímica , Eletrodos , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Estrutura Molecular , Espectrometria por Raios X
9.
Environ Sci Pollut Res Int ; 23(7): 6546-62, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26635222

RESUMO

Aerosol composition and properties variation under the advection of different air masses were investigated, as case studies, by contemporary measurements over the atmospheric column and at the ground in a semi-rural site in South Italy. The absence of local strong sources in this area allowed to characterize background aerosol and to compare particle mixing effects under various atmospheric circulation conditions. Aerosol optical depth (AOD) and Ǻngström parameters from radiometric measurements allowed the detection and identification of polluted, dust, and volcanic atmospheric conditions. AODs were the input for a suitable model to evaluate the columnar aerosol composition, according to six main atmospheric components (water-soluble, soot, sea salt accumulation, sea salt coarse, mineral dus,t and biological). Scanning electron microscope (SEM) analysis of particulate sampled with a 13-stage impactor at the ground showed not only fingerprints typical of the different air masses but also the effects of transport and aging on atmospheric particles, suggesting processes that changed their chemical and optical properties. Background columnar aerosol was characterized by 72% of water-soluble and soot, in agreement with ground-based findings that highlighted 60% of contribution from anthropogenic carbonate particles and soot. In general, a good agreement between ground-based and columnar results was observed. Under the advection of trans-boundary air masses, water-soluble and soot were always present in columnar aerosol, whereas, in variable percentages, sea salt and mineral particles characterized both dust and volcanic conditions. At the ground, sulfates characterized the amorphous matrix produced in finer stages by the evaporation of solutions of organic and inorganic aerosols. Sulfates were also one of the key players involved in heterogeneous chemical reactions, producing complex secondary aerosol, as such clay-sulfate internally mixed particle externally mixed with soot chains.


Assuntos
Poluentes Atmosféricos/análise , Poeira/análise , Monitoramento Ambiental/métodos , Modelos Teóricos , Fuligem/análise , Sulfatos/análise , Aerossóis , Itália , Solubilidade , Propriedades de Superfície
10.
Appl Radiat Isot ; 100: 79-83, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25468288

RESUMO

Important thermoluminescence (TL) properties of five (5) different core sizes Ge-doped optical fibers have been studied to develop new TL material with better response. These are drawn from same preform applying different speed and tension during drawing phase to produce Ge-doped optical fibers with five (5) different core sizes. The results of the investigations are also compared with most commonly used standard TLD-100 chips (LiF:Mg,Ti) and commercial multimode Ge-doped optical fiber (Yangtze Optical Fiber, China). Scanning Electron Microscope (SEM) and EDX analysis of the fibers are also performed to map Ge distribution across the deposited region. Standard Gamma radiation source in Secondary Standard Dosimetry Lab (SSDL) was used for irradiation covering dose range from 1Gy to 10Gy. The essential dosimetric parameters that have been studied are TL linearity, reproducibility and fading. Prior to irradiation all samples ∼0.5cm length are annealed at temperature of 400°C for 1h period to standardize their sensitivities and background. Standard TLD-100 chips are also annealed for 1h at 400°C and subsequently 2h at 100°C to yield the highest sensitivity. TL responses of these fibers show linearity over a wide gamma radiation dose that is an important property for radiation dosimetry. Among all fibers used in this study, 100µm core diameter fiber provides highest response that is 2.6 times than that of smallest core (20µm core) optical fiber. These fiber-samples demonstrate better response than commercial multi-mode optical fiber and also provide low degree of fading about 20% over a period of fifteen days for gamma radiation. Effective atomic number (Zeff) is found in the range (13.25-13.69) which is higher than soft tissue (7.5) however within the range of human-bone (11.6-13.8). All the fibers can also be re-used several times as a detector after annealing. TL properties of the Ge-doped optical fibers indicate promising applications in ionizing radiation dosimetry.

11.
Carbohydr Polym ; 99: 517-26, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24274538

RESUMO

Prussian blue (PB) was immobilized in alginate capsules. The composite sorbent was used for the recovery of Tl(I) ions from slightly acidic solutions: optimum pH being close to 4. The sorption isotherm can be described by the bi-site Langmuir sorption isotherm. This means that the metal ion can be bound through two different sorption sites: one having a strong affinity for Tl(I) (probably PB), the other having a lower affinity (probably the encapsulating material). The kinetics are described by either the pseudo-second order rate equation or the Crank's equation (resistance to intraparticle diffusion). The ionic strength (increased by addition of NaCl, KCl or CaCl2) slightly decreased sorption capacity. The SEM-EDX analysis of PB-alginate capsules (before and after Tl(I) sorption) shows that the PB is homogeneously distributed in the capsules and that all reactive groups remain available for metal binding.


Assuntos
Alginatos/química , Ferrocianetos/química , Tálio/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cápsulas , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Concentração Osmolar , Espectrometria por Raios X , Termodinâmica
12.
J Ginseng Res ; 37(4): 483-90, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24235863

RESUMO

Gamma-irradiation (0-7 kGy) of ginseng is permitted in Korea for the purpose of microbial decontamination; with strict labeling, traceability and monitoring requirements. An identification study was conducted to determine the photostimulated-luminescence (PSL) and thermoluminescence (TL) properties of gamma-irradiated fresh and white ginsengs cultivated in different areas. Dosedependent PSL-based screening was possible for white ginseng samples; however, inappropriate results from non-irradiated fresh ginseng samples were obtained, showing intermediate (700 to 5,000) or positive (T2 >5,000, irradiated) PSL counts due to the abundance of minerals on the surfaces of the samples. TL analysis of separated minerals from all non-irradiated samples gave TL glow curves of low intensity with a maximum peak after 300℃. However, well-defined irradiation-specific (high intensity with a maximum peak at about 200℃) glow curves were observed for all the irradiated samples, regardless of their type and origins. TL ratios (first glow curve /second glow curve) were also determined to confirm the irradiated (>0.1) and non-irradiated (<0.1) results. SEM-EDX (scanning electron microscope-energy dispersive X-ray) and XRD (X-ray diffraction) spectroscopic analyses showed that feldspar and quartz minerals were the main source for the typical radiation-specific luminescence properties.

13.
J Colloid Interface Sci ; 409: 141-50, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23992944

RESUMO

Ammonium molybdophosphate and Phozir (alone or in combination) have been encapsulated in alginate beads for the synthesis of rubidium sorbents. SEM and SEM-EDX analyses confirm the homogeneity of the sorbents in terms of composition and metal binding. AMP sorbent is less sensitive to pH than Phozir, and optimum pH is close to pH 3 for the binding of Rb(I). The Langmuir equation fitted well sorption isotherms and the maximum sorption capacities were in the range 0.65-0.74 mmol Rb g(-1). The resistance to intraparticle diffusion contributes to control uptake kinetics (effect of particle size) though the presence of solid inorganic particles reduces the impact of drying alginate capsules (preventing the collapse of the porous structure during the drying step). Breakthrough curves demonstrate the potential of these sorbents for the dynamic sorption of Rb(I) while using ammonium chloride (combined to nitric acid) allows recovering Rb(I) from loaded sorbents.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA