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1.
Polymers (Basel) ; 16(13)2024 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-39000786

RESUMO

High-quality, 3D-shaped, SiO2 colloidal photonic crystals (ellipsoids, hyperboloids, and others) were fabricated by self-assembly. They possess a quadratic surface and are wide-angle-independent, direction-dependent, diffractive reflection crystals. Their size varies between 1 and 5 mm and can be achieved as mechanical-resistant, free-standing, thick (hundreds of ordered layers) objects. High-quality, 3D-shaped, polystyrene inverse-opal photonic superstructures (highly similar to diatom frustules) were synthesized by using an inside infiltration method as wide-angle-independent, reflective diffraction objects. They possess multiple reflection bands given by their special architecture (a torus on the top of an ellipsoid) and by their different sized holes (384 nm and 264 nm). Our hanging-drop self-assembly approach uses setups which deform the shape of an ordinary spherical drop; thus, the colloidal self-assembly takes place on a non-axisymmetric liquid/air interface. The deformed drop surface is a kind of topological interface which changes its shape in time, remaining as a quality template for the self-assembly process. Three-dimensional-shaped colloidal photonic crystals might be used as devices for future spectrophotometers, aspheric or freeform diffracting mirrors, or metasurfaces for experiments regarding space-time curvature analogy.

2.
Healthcare (Basel) ; 11(14)2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37510545

RESUMO

The paper presents the evolution of the concentration level for four particle size groups of microaerosols (1.0, 2.5, 4.0 and 10.0 µm) in correlation with the microclimatic characteristics (temperature, humidity, lighting, pressure and concentration in CO2 and O2) in three active areas of the Targu Ocna Saltworks, currently used in treatments with solions (hydrated aerosols): in the vicinity of the walls of the old mining salt room, where there is a semi-wet static regime (SSR); in the transition area between the old rooms of exploitation with the semi-wet dynamic regime (DSR); and in the area of the waterfall and the marshy lake with the dynamic wet regime (DWR). The first and last halochamber are the ones recommended for cardio-respiratory, immuno-thyroid and osteo-muscular conditions, as well as in psycho-motor disorders. Based on questionnaires carried out over the course of a year, between 1 September 2021-31 August 2022, in two periods of stationing/treatment: a cold one (15 September 2021-15 December 2021) and a warm one (1 May 2022-30 July 2022), correlated with the data from the Salina medical office, achieved the profile of the improvement rate of the patients' ailments depending on the type of treatment (working regime in halochambers). These studies have allowed the optimization of the treatment conditions in the artificial surface halochambers in order to reduce the stationary period and optimize the treatment cycles.

3.
Materials (Basel) ; 16(7)2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-37049066

RESUMO

Hybrid fillers can be produced via various methods, such as physical mixing and chemical modification. However, there is a limited number of studies on the effect of hybridisation on the mechanical performance of hybrid filler-reinforced polymer composites, especially in the context of wear performance. This study investigated the wear resistance of carbon nanotubes (CNTs)/alumina hybrid-filled phenolic composite, where two hybrid methods were used to produce the CNTs/alumina hybrid filler. The CNTs/alumina (CVD hybrid) was synthesised using the chemical vapour deposition (CVD) method, whereas the CNTs-/alumina (physically hybrid) was prepared using the ball milling method. The CNTs/alumina hybrid filler was then used as a filler in the phenolic composites. The composites were prepared using a hot mounting press and then subjected to a dry sliding wear test using a pin-on-disc (POD) tester. The results show that the composite filled with the CVD hybrid filler (HYB composite) had better wear resistance than the composite filled with physically hybrid filler (PHY composite) and pure phenolic. At 5 wt%, the HYB composite showed a 74.68% reduction in wear, while the PHY composite showed a 56.44% reduction in wear compared to pure phenolic. The HYB composite exhibited the lowest average coefficient of friction (COF) compared to the PHY composite and pure phenolic. The average COF decreased with increasing sliding speeds and applied loads. The phenolic composites' wear and average COF are in the order HYB composite < PHY composite < pure phenolic under all sliding speeds and applied loads.

4.
Polymers (Basel) ; 16(1)2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38201697

RESUMO

High-quality convex colloidal photonic crystals can be grown on the tip of an optical fiber by self-assembly using the hanging drop method. They are convex-shaped, produce the diffraction of reflecting light with high efficiency (blazing colors), and have a high curvature. The convex colloidal crystals are easily detachable and, as free-standing objects, they are mechanically robust, allowing their manipulation and use as convex reflective diffraction devices in imaging spectrometers. Currently, the same characteristics are obtained by using gratings-based structures. The optical fiber/colloidal crystal interface is disordered; thus, no light diffraction can be registered. The ordering at this interface was highly increased by forming a polystyrene spacer on the optical fiber tip, which served as a self-assembly substrate for silica colloid, as a mechanical bond between the fiber and the crystal, and as a filler reservoir for an inverse-opal synthesis. The silica opal-like grown on the optical fiber tip can be transformed into a high-quality polystyrene (blazing colors) inverse-opal by using the polystyrene spacer as a filler. We found that the colloidal crystal axisymmetric self-assembles onto the optical fiber tip only if a maximum volume of the colloid drop is settled on a flat end of the polystyrene spacer.

5.
Diagnostics (Basel) ; 12(9)2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36140537

RESUMO

The assessment of fibrosis in chronic liver diseases using non-invasive methods is an important topic in hepatology. The aim of this study is to identify patients with non-alcoholic fatty liver disease (NAFLD) and advanced liver fibrosis by establishing correlations between biological/ultrasound markers and non-invasively measured liver stiffness. This study enrolled 116 patients with non-alcoholic fatty liver disease, which were evaluated clinically, biologically, and by ultrasound. Liver fibrosis was quantified by measuring liver stiffness by shear wave elastography (SWE). Multiple correlation analysis of predictors of liver fibrosis identified a number of clinical, biological, and ultrasound parameters (BMI, blood glucose, albumin, platelet count, portal vein diameter, bipolar spleen diameter) that are associated with advanced liver fibrosis in patients with non-alcoholic fatty liver disease. The correlations between the degree of liver fibrosis and the risk values of some serological and ultrasound markers obtained in our study could be useful in clinical practice for the identification of advanced fibrosis in patients with NAFLD.

6.
Polymers (Basel) ; 14(11)2022 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-35683831

RESUMO

Silica and polystyrene spheres with a small size ratio (r = 0.005) form by sequential hanging drop self-assembly, a binary colloidal crystal through which calcination transforms in a silica-ordered concavity array. These arrays are capable of light Bragg diffraction and shape dependent optical phenomena, and they can be transformed into inverse-opal structures. Hierarchical 2D and 3D super-structures with ordered concavities as structural units were fabricated in this study.

7.
Polymers (Basel) ; 13(23)2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34883585

RESUMO

A polyester fabric with rectangular openings was used as a sacrificial template for the guiding of a sub-micron sphere (polystyrene (PS) and silica) aqueous colloid self-assembly process during evaporation as a patterned colloidal crystal (PCC). This simple process is also a robust one, being less sensitive to external parameters (ambient pressure, temperature, humidity, vibrations). The most interesting feature of the concave-shape-pattern unit cell (350 µm × 400 µm × 3 µm) of this crystal is the presence of triangular prisms at its border, each prism having a one-dimensional sphere array at its top edge. The high-quality ordered single layer found inside of each unit cell presents the super-prism effect and left-handed behavior. Wider yet elongated deposits with ordered walls and disordered top surfaces were formed under the fabric knots. Rectangular patterning was obtained even for 20 µm PS spheres. Polyester fabrics with other opening geometries and sizes (~300-1000 µm) or with higher fiber elasticity also allowed the formation of similar PCCs, some having curved prismatic walls. A higher colloid concentration (10-20%) induces the formation of thicker walls with fiber-negative replica morphology. Additionally, thick-wall PCCs (~100 µm) with semi-cylindrical morphology were obtained using SiO2 sub-microspheres and a wavy fabric. The colloidal pattern was used as a lithographic mask for natural lithography and as a template for the synthesis of triangular-prism-shaped inverted opals.

8.
Healthcare (Basel) ; 9(3)2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800429

RESUMO

The aim of this study was to assess the delays that can potentially occur in the emergency transfer of patients with ST-elevation myocardial infarction (STEMI) to percutaneous coronary intervention (PCI) centers. We conducted a retrospective study using the medical reports pertaining to 97 patients who presented to the Emergency Department of the Emergency County Hospital of Galati during the year of 2018 with the diagnosis of STEMI and meeting eligibility criteria for PCI, thus warranting transfer to a hospital with PCI facilities. The pick-up time of patients diagnosed with acute myocardial infarction from the emergency department by the transfer crew is significantly shorter (p < 0.05) than those transferred by air, regardless of the PCI center to which the transfer was performed, Iasi or Bucharest, when compared to the time required to process the patients transferred by land to the same PCI centers. The results of the study shows that the helicopter use for transferring acute myocardial infarction patients to a PCI center must be considered, given the distance between non-PCI and PCI centers is over 200 km.

9.
Microorganisms ; 9(1)2020 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-33379317

RESUMO

Mycotoxins are secondary metabolites produced by various fungi. A very important category of mycotoxins are aflatoxins, considered to be the most dangerous in humans. Aflatoxin B1, well known as a favorable factor in the occurrence of hepatocellular carcinoma in humans, is the most controversial of all mycotoxins. Aflatoxins, found in naturally contaminated food, are resistant to degradation by heat. Current food processing practices and conventional storage conditions do not completely eliminate aflatoxin contamination from the food supply chain. Long storage food products-such as peanuts, pistachio, nuts in general, and dried fruits-are susceptible to aflatoxins contamination. The type of plastic material can influence the concentration of aflatoxins during storage due to the permeability to gas and moisture exchange with the external milieu. Nuts in general and dried fruits are consumed in large quantities worldwide. Therefore, herein we investigated the effect of plastic material on the total aflatoxins and aflatoxin B1 content in 64 samples of nuts and dried fruits packed and stored in low-density polyethylene (LDPE), polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). The method consisted in a cleanup procedure using immunoaffinity columns coupled with RIDASCREEN FAST immunoenzymatic competitive assays based on the ELISA technique. Collected data were subjected to statistical analysis and multiple comparisons tests were applied. From the total analyzed samples, 14.06% exceeded the maximum admitted European levels for total aflatoxins. The highest concentrations of total aflatoxins were obtained from samples packed in LDPE, followed by PP, PE, and PET. Aflatoxin B1 was detected in all samples packed in LDPE, PP, and PE. Most of the samples packed in PET had concentrations <1 µg/kg. These results indicate that nuts in general packed and stored in LDPE are more prone to contamination with aflatoxins, while PET is more suitable for maintaining the quality and safety of these products.

10.
Materials (Basel) ; 13(21)2020 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-33114524

RESUMO

The paper explores the potentiality of an experimental multianalytic protocol with appropriate methodology for determining the chemical and morphostructural characteristics of two old documents on parchment support. Such a protocol can authenticate and assess the state of conservation under the influence of environmental factors during storage and archival documentation, thus advancing preventive and prophylactic measures in "treasure" deposits such as the National Archives of Romania, where these documents are kept. The work methodology consisted of three stages. The first stage consists of visual observation for identifying deteriorations and degradations, alongside the selection of representatives' areas from where micro-samples were collected. The second stage involves Scanning Electron Microscopy coupled by Energy Dispersive X-ray Spectrometry (SEM-EDX) analysis, for highlighting the morphology and determining the elemental composition; lastly, the Fourier-transform infrared (FTIR) analysis and correlation of results establish the chemical and morphostructural changes. The use of this gradual system of analyses allowed determining the differences between these two documents in terms of the materials used for producing them, their manufacturing technologies, the writing and ornamentation, and the overall state of conservation. The results provided the first accurate picture of the chemical nature and manufacturing of the two parchment documents by determining the main characteristics of the collagen and of the finishing, writing, and decoration materials, in view of the natural aging through the oxidative and gelatinization processes of the collagen. The SEM-EDX results revealed the morphological changes of the parchment that occurred at various levels in the collagen fibrous mesh and established the state of conservation of the support, writing, and decorations.

11.
Materials (Basel) ; 12(23)2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31766445

RESUMO

The paper presents the results of ample investigations performed on industrial and traditional ceramics of fired clay used in processes of water potabilization in the last stage of filtration, after that of active charcoal. Using the data obtained through the scanning electron microscope coupled with energy dispersive X-ray analysis (SEM-EDX) and pH analyses, on the basis of the atomic composition and free concentration of hydronium ions, the normal caustic (Si/Al) and summative [(Si+Ti+FeIII+Cl)/(Al+Ca+Mg+Na+K)] modules were assessed, which were correlated with the free acidity and, respectively, the capacity of absorption and ionic exchange of the Fe3+ and Al3+ ions. The study allowed the selection, on the basis of the caustic module, of the ceramics with high capacity for ionic exchange.

12.
Environ Monit Assess ; 187(2): 15, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25626566

RESUMO

Saline aerosols resulted from natural or artificial sources are used for therapeutic environments. The paper presents the influence of the NaCl aerosols resulted in situ in dynamic halochambers, by structural reformation of saline aerosols in the presence of pentahydrol, on the increase in weight and height of children, as a result of systemically controlled practice of team and individual physical education games, with subjects of ages from 10 to 15. For reference, we used children of the same age and with the same physical education program, but whose activities were performed in open spaces, or in gym classrooms, without saline aerosols. Our study emphasized the fact that the NaCl aerosols formed in situ, in the atmosphere of the halochamber, at a rate of over 0.600 mg/m(3) of saline aerosols, enhanced the growth and weight gain at a higher rate in girls than in boys and at an obviously higher rate than that reported in the children who performed physical exercises in normal conditions, over a period of 3 years. All the data were statistically processed in order to evaluate the influence of the aerosols. The study reports the therapeutic benefits of salt exposure in children's development.


Assuntos
Aerossóis/uso terapêutico , Desenvolvimento Infantil , Cloreto de Sódio/uso terapêutico , Adolescente , Aerossóis/administração & dosagem , Estatura , Peso Corporal , Criança , Feminino , Humanos , Masculino , Cloreto de Sódio/administração & dosagem
13.
Microsc Res Tech ; 77(12): 1060-70, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25234164

RESUMO

The study presents an old icon painted in egg tempera on lime wood, with a poor conservation condition and clogged dirt deposits. The icon is attributed to an anonymous painter of XIXth century and to the neo-classical style of painting. The painting layer was done with only a hand full of pigments, earth colors that were often used in painting the icons from XVIIth to XIXth century in Eastern Europe, that have Byzantine influences. Taking into consideration the nature and the structure of the materials from the upper layers of the painting, affected by deposits of dirt over time, a series of cleaning recipes were studied, using the so called cleaning tests with compatible mixtures of different juices and infusion from indigenes plants, that were freshly done and odorless. A low alkaline 95% ethyl alcohol solution, combined with a few drops of ammoniac 25%, was used as a reference system, due to its compatibility with the greasy deposits found on the polychrome layer and on the wood. The cleaning capacity of the new systems used, in comparison with the standard solution, was analyzed through modern analytical methods of evaluating the degree of cleaning, more exactly by means of visible and UV reflectography, CIE L*a*b* colorimetry by reflection assisted by SEM-EDX and IR spectroscopy.


Assuntos
Detergentes/química , Microscopia Eletrônica de Varredura , Pinturas , Cor , Pintura , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
14.
Microsc Res Tech ; 77(11): 918-27, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25092177

RESUMO

Our article presents the results of the analyses we performed by corroborating the Optical Microscopy, Scanning Electron Microscopy, Energy Dispersive Xray Analysis and micro Fourier Transformed InfraRed Analysis techniques to identify the archaeo-metallurgic casting and ornamentation procedure of a decorated disk-butted axe, which was discovered recently east of the Carpathian mountains, in the Moldavian Plateau. There are few known axes of that type found (A1, according to the usual typologies), as they are specific to the Middle Bronze Age period west of the Carpathians-the Wietenberg, Suciu de Sus, and Otomani-Füzesabony cultures. The experimental data on the item under study revealed the fact that after casting it in molds made from porous silicone-based stone, the object was coated with a thin layer, by immersing it in a lightly fusible tin alloy, whose main alloy component was copper and arsenic and iron as secondary components. After refining the shiny white layer, they applied a beautiful decoration pattern made by incision and engraving. This battle axe was an indication of higher status, such items usually being owned by community leaders. This important fact proves that the ancient metallurgic craftsmen were able to elaborate and manufacture various alloys from which they made beautiful objects and it also offers a new insight into the social and symbolic function of certain antique bronze items.

15.
Microsc Res Tech ; 76(6): 564-71, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23495175

RESUMO

The article studies thermal resistance variation by analyzing the colorimetric parameters correlated with the optical microscopy data of two groups of ceramic pigments obtained by co-precipitation in aqueous medium of phosphate anion and of a mixture of chromium phosphate with various chromophore cations. This research enabled us to reveal the thermal thresholds/domains within which significant color changes occur, thus allowing the choice of pigments compatible with the thermal varnishing-glazing processes involved in the manufacture of tesserae for mosaic and stained glass and of colored materials for floor tiles, wall tiles and painted porcelain.

16.
Microsc Res Tech ; 76(2): 209-18, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23174822

RESUMO

Consolidation of frail, degraded wood is a key issue of wooden cultural heritage conservation. Paraloid B72 is one of the most often used consolidant in conservation practice. The present research aimed at formulating stable consolidation solutions of Paraloid B72 with ZnO nano-additives and at determining the influence of these additives on the penetration pathways, retention of the consolidation material into wood and on the water behavior of the treated wood. The experiments were performed on sound samples of aspen (Populus tremula). The addition of nano-ZnO slightly increased the uptake and retention of the consolidant within the wooden structure and led to hydrophobic surfaces. However, the influence of nano-ZnO additives to the water absorption was not conclusive. Scanning Electron Microscope coupled with an EDX Detector investigation proved vessels, fibers, and interconnecting pits as main pathways of consolidant penetration into the wooden structure as well as the presence and distribution of nano-ZnO.


Assuntos
Quimioterapia de Consolidação/métodos , Nanoestruturas , Doenças das Plantas/terapia , Madeira/efeitos dos fármacos , Óxido de Zinco/metabolismo , Microscopia Eletrônica de Varredura , Populus , Espectrometria por Raios X
17.
Microsc Res Tech ; 75(12): 1711-6, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23033318

RESUMO

This article presents the SEM-EDX and microFTIR study and the corrosion behavior of new five types of phosphated coatings obtained by coprecipitation in acid aqueous medium of some metal cations, pursuing the influence of the addition of other cations and a moderator of precipitation, on the uniformity and compactness of the layers and on the morphology of dendritic structure of Zn(II) and Fe(II) phosphates.

18.
Microsc Res Tech ; 75(12): 1646-52, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22865394

RESUMO

The article presents the experimental results obtained by combining noninvasive techniques (OM, SEM/EDX, XRF) to analyze three artifacts made of copper alloys discovered in a inhumation tomb (2) and in the soil profile (1) in archaeological sites from Neamt County Romania. To uncover the mechanism of alteration thereof during their longtime underground stay in specific chemical conditions and under the influence of other pedological factors, the corrosion products must be identified. The excess of the chloride ion, from burial site, disturbs the Liesegang effect, transforming the bulk in a stratified sponge structure with chlorapatite and hydroxyapatite. Some of the compounds from primary and secondary patina can be found on the surface of the bulk, as color stains. The presence of alloy components (Cu, Sn, Pb, Zn, Fe, etc.) and of the underground contamination components, allowed us to establish the origin of the ore, the manufacture technology and we identified other materials which affected the artifacts after abandonment.

19.
Microsc Res Tech ; 75(11): 1467-74, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22718441

RESUMO

This article presents the atypical formations in the structure of the corrosion crust and in the partially mineralized metallic core, which resulted during the underground stay of a bronze shield, dated between the 1st century B.C. and the 1st century A.D. For our study, we choose a representative fragment from the rim of the shield, which was analyzed by optical microscopy and by electron microscopy coupled with energy-dispersive X-ray spectroscopy, to study its morphology, its composition, and the location of chemical compounds on the surface and inside the bulk formed during the underground stay, by processes of chemical and physical alteration, assisted by contamination with structural elements from the site. Those processes, by monolithization and mineralization formed a series of structures consisting of congruent elements and phases with a complex composition. Those formations, defined as surface effects generated by exogenous factors and endogenous factors inside the bulk, are frequently found in ancient bronze objects (such as the exterior flat mole formations and the Liesegang effect in the stratigraphic structure of the bulk). Some of those structures have atypical characteristics as regards their structure, composition, and formation mechanism, which may be used in archeometry. Moreover, that includes the object in the category of special cases, in terms of artifact evolution during underground stay and of the atypical formations resulted from the action of pedological and environmental factors.

20.
J Colloid Interface Sci ; 358(2): 621-5, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21477807

RESUMO

The focus of the present article is the study of the influence of gravity on the particle deposition profiles on a solid substrate during the evaporation of sessile, hanging and sandwiched hanging drops of colloidal particle suspensions. For concentrations of nanoparticles in the colloidal solutions in the range 0.0001-1 wt.%, highly diluted suspensions will preferentially form rings while concentrated suspensions will preferentially form spots in both sessile and hanging drop evaporation. For intermediary concentrations, the particle deposition profiles will depend on the nanoparticle aggregation dynamics in the suspension during the evaporation process, gravity and on the detailed evaporation geometry. The evaporation of a drop of toluene/carbon nanoparticle suspension hanging from a pendant water drop will leave on the substrate a circular spot with no visible external ring. By contrast, a clear external ring is formed on the substrate by the sessile evaporation of a similar drop of suspension sandwiched between a water drop and the substrate. From the application viewpoint, these processes can be used to create preferential electrical conductive carbon networks and contacts for arrays of self-assembled nanostructures fabricated on solid substrates as well as on flexible polymeric substrates.

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